This file was created by the TYPO3 extension publications --- Timezone: CEST Creation date: 2026-04-09 Creation time: 03:35:34 --- Number of references 2993 article Li2026 Article 2026 10.1016/j.cretres.2025.106201 Cretaceous Research 177 https://www.scopus.com/inward/record.uri?eid=2-s2.0-105012125200&doi=10.1016%2fj.cretres.2025.106201&partnerID=40&md5=bd8b362fe2ba4a1b3ca389c70affd3f9 Cited by: 0 Shan Li Huaichun Wu Qiang Fang Runjian Chu Meinan Shi Guang Yang Yuan Gao Xiaojuan Ma Youfeng Gao Chengshan Wang article Lubbe2026 Article 2026 10.5194/sd-35-39-2026 Scientific Drilling 35 39--53 https://sd.copernicus.org/articles/35/39/2026/ R. Lubbe A. J. Allwright S. S. Lange F Roelofse article Lemke2026 Article 2026 10.1016/j.geothermics.2025.103564 Geothermics 136 https://www.scopus.com/inward/record.uri?eid=2-s2.0-105030205449&doi=10.1016%2fj.geothermics.2025.103564&partnerID=40&md5=a86940241932fe17e497fb8516b1e854 Cited by: 0; All Open Access, Hybrid Gold Open Access Kim Lemke György Hetényi Alexia Secrétan Junjian Li Andrew Greenwood Eva Caspari Christoph Schmidt Georgina King Ueli Schärli Ludovic Baron Othmar Müntener article Lin2026 Article 2026 10.1016/j.cretres.2025.106217 Cretaceous Research 178 https://www.scopus.com/inward/record.uri?eid=2-s2.0-105016339670&doi=10.1016%2fj.cretres.2025.106217&partnerID=40&md5=47b8a06f9d115c406d7729c8f5d0690c Cited by: 0 Miaoqin Lin Jianguo Li Yixiao Wu Tan Tan Yigang Xu article FAN2026105284 The terminal Ediacaran (ca. 551–533 Ma) was characterized by profound biological innovations and environmental upheavals, in which phosphorus (P)—the ultimate limiting nutrient for marine productivity—is postulated to have played a key role. However, P availability in the terminal Ediacaran ocean remains uncertain due to the lack of an appropriate proxy record. To better reconstruct seawater P levels during this time interval, we analyzed carbonate-associated phosphate [CAP; expressed as CAP/(Ca + Mg)], a new proxy for P availability in ancient oceans, in three upper Ediacaran successions: the Nama Group (Namibia), the Shibantan Member of the Dengying Formation (Wuhe, South China), and the Algal Dolomite, Gaojiashan and Beiwan members of the Dengying Formation (Gaojiashan, South China). Our results reveal consistently low CAP/(Ca + Mg) values (range: 0.02–0.69 mmol/mol, mean: 0.13 ± 0.01 mmol/mol, 2σ, the same below) for all study sections, falling at the lower end of modern marine carbonate values. Lithofacies, carbonate oxygen isotopes, Mn/Sr and Mg/(Mg + Ca) ratios indicate possible influences from release of Fe-bound P, meteoric diagenesis, recrystallization or dolomitization. The low CAP/(Ca + Mg) values thus represent a maximum estimate for the seawater P availability. The low CAP values from two geographically separated cratons likely reflect a generally small oceanic inorganic P reservoir at least in shelves. This study provides insights into the interplay between nutrient cycling, redox dynamics, and biological evolution during one of the most pivotal transitional periods in Earth history. 2026 0921-8181 https://doi.org/10.1016/j.gloplacha.2026.105284 Global and Planetary Change 258 105284 Redox conditions, Nama Assemblage, Biomineralization, Oxygen level, Marine productivity, South China https://www.sciencedirect.com/science/article/pii/S0921818126000056 Yonghan Fan Meng Cheng Xinyang Chen Catherine Rose Haiyang Wang Zihu Zhang Thomas J. 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Lane Clive Oppenheimer Céline-Marie Vidal Christina J. Manning Francesca Forni Hendrik Vogel Satria Bijaksana James M. Russell article Akkiraju2025 Article 2025 10.1016/j.ijrmms.2025.106273 International Journal of Rock Mechanics and Mining Sciences 195 https://www.scopus.com/inward/record.uri?eid=2-s2.0-105016784376&doi=10.1016%2fj.ijrmms.2025.106273&partnerID=40&md5=c57f547680bca72962aa1c52a7694237 Cited by: 0 Vyasulu V. Akkiraju Deepjyoti Goswami Jochem Kueck Gerd Klee Brijesh K. Bansal Sukanta Roy article Confal2025 Article 2025 10.4401/ag-9279 Annals of Geophysics 68 5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-105025251083&doi=10.4401%2fag-9279&partnerID=40&md5=5ab419c9f251bfaf5fa1093594bd68b7 Cited by: 2; All Open Access, Gold Open Access Judith M. Confal Simone Salimbeni Adriano Cavaliere Stefania Danesi Irene Molinari Maddalena Errico Ludovic Baron Steffen Uhlmann György Hetényi Silvia Pondrelli article Merseburger2025 Article 2025 10.1016/j.lithos.2025.108261 Lithos 516-517 https://www.scopus.com/inward/record.uri?eid=2-s2.0-105016850910&doi=10.1016%2fj.lithos.2025.108261&partnerID=40&md5=fc74efc8fb2f072bf2b300e2857a1642 Cited by: 0 Sven Merseburger Felix Marxer Ingo Horn Dieter Garbe-Schönberg Ulrike Westernströer Sandrin T. Feig Andreas B. Kaufmann François Holtz Jürgen Koepke article Bowyer2025 Review 2025 10.1016/j.earscirev.2025.105169 Earth-Science Reviews 268 https://www.scopus.com/inward/record.uri?eid=2-s2.0-105006603327&doi=10.1016%2fj.earscirev.2025.105169&partnerID=40&md5=b5194e3156879c66347080ba771fc812 Cited by: 3; All Open Access, Green Open Access, Hybrid Gold Open Access Fred T. Bowyer Fabio Messori Rachel Wood Ulf Linnemann Esther Rojo-Perez Mandy Zieger-Hofmann Johannes Zieger Junias Ndeunyema Martin Shipanga Bontle Mataboge Dan Condon Catherine V. Rose Collen-Issia Uahengo Sean P. Gaynor Inigo A. Müller Gerd Geyer Torsten Vennemann Joshua H.F.L. Davies Maria Ovtcharova article Kearney2025 Article 2025 10.1016/j.quascirev.2024.109165 Quaternary Science Reviews 352 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85216572198&doi=10.1016%2fj.quascirev.2024.109165&partnerID=40&md5=9745bf6100316fbf1caafeaff2ca8d7e Cited by: 2; All Open Access, Hybrid Gold Open Access Rebecca J. Kearney Jeremy Goff Victoria Smith Markus J. Schwab Yavuz Özdemir Özgür Karaoǧlu Matthew Thirlwall Dan N. Barfod Oona Appelt Christina Günter Jan Fietzke Nadine Pickarski Ina Neugebauer Rik Tjallingii Achim Brauer article Collins20253931 Article 2025 10.5194/bg-22-3931-2025 Biogeosciences 22 3931 – 3948 15 https://www.scopus.com/inward/record.uri?eid=2-s2.0-105013248373&doi=10.5194%2fbg-22-3931-2025&partnerID=40&md5=d155856489454fab7d29eecee9770947 Cited by: 0 Evan R. Collins Troy M. Ferland Isla S. Castañeda R. Bernhart Owen Tim K. Lowenstein Andrew S. Cohen Robin W. Renaut Molly D. O’Beirne Josef P. Werne article Mngadi202533 Article 2025 10.17159/2411-9717/3445/2025 Journal of the Southern African Institute of Mining and Metallurgy 125 33 – 42 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85217887529&doi=10.17159%2f2411-9717%2f3445%2f2025&partnerID=40&md5=5d60f228e9eba0d26e9f3c13f825fde8 Cited by: 0; All Open Access, Gold Open Access S.B. Mngadi M.S.D. Manzi N.Z. Nkosi R.J. Durrheim H. Ogasawara Y. Yabe article Löwe2025405 Article 2025 10.1093/gji/ggaf046 Geophysical Journal International 241 405 – 436 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85218474170&doi=10.1093%2fgji%2fggaf046&partnerID=40&md5=b78daef0d3b00982d9531651b8b85e0d Cited by: 0; All Open Access, Gold Open Access R. Löwe J. Renner C. Pascal B. Adl-Zarrabi N. Balling T.S. Bording M. Long G. Schwarz J. Sundberg article Michibayashi2025 Article 2025 10.1016/j.lithos.2025.107970 Lithos 496-497 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85216491816&doi=10.1016%2fj.lithos.2025.107970&partnerID=40&md5=3aa14442fc5f6ffb7131e84e37e217e7 Cited by: 0; All Open Access, Green Open Access, Hybrid Gold Open Access Katsuyoshi Michibayashi Yuki Kakihata Itsuki Natsume Takeo Okuwaki Marguerite Godard Peter Kelemen article Dutoit2025 Article 2025 10.1029/2025GC012168 Geochemistry, Geophysics, Geosystems 26 5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-105004812171&doi=10.1029%2f2025GC012168&partnerID=40&md5=2926d4cd958633216ac0b094ee62f394 Cited by: 0 H. Dutoit L. Truche F.V. Donzé T. Wiersberg M.L. Doan J. Li A. Greenwood E. Caspari N. Lefeuvre J. Dominique S. Auclair L. Masci G. Hetényi M. Venier O. Müntener article Ferruginous conditions prevailed through Earth’s early oceans history, yet our understanding of biogeochemical cycles in anoxic iron-rich, sulfate-poor sediments remains elusive in terms of redox processes and organic matter remineralization. Using comprehensive geochemistry, cell counts and metagenomic data, we investigated the taxonomic and functional distribution of the microbial subsurface biosphere in Lake Towuti, a stratified ferruginous analogue. Below the zone in which pore water becomes depleted in electron acceptors, cell densities exponentially decreased while microbial assemblages shifted from iron- and sulfate-reducing bacterial populations to fermentative anaerobes and methanogens, mostly selecting Bathyarchaeia below the sulfate reduction zone. Bathyarchaeia encode metabolic machinery to cycle and assimilate polysulfides via sulfhydrogenase, sulfide dehydrogenase and heterodisulfide reductase, using dissimilatory sulfite reductase subunit E and rubredoxin as carriers. Their metagenome-assembled genomes showed that carbon fixation could proceed through the complete methyl-branch Wood-Ljungdahl pathway, conducting (homo)acetogenesis in the absence of methyl coenzyme M reductase. Further, their partial carbonyl-branch, assumed to act in tetrahydrofolate interconversions of C1 and C2 compounds, could support close interactions with methylotrophic methanogens in the fermentation zone. Thus, Bathyarchaeia appeared capable of coupling sulfur-redox reactions with fermentative processes, using electron bifurcation in a redox-conserving (homo)acetogenic Wood-Ljungdahl pathway, and revealing geochemical ferruginous conditions at the transition between the sulfate reduction and fermentation zone as their preferential niche. 2024 09 2730-6151 10.1093/ismeco/ycae112 ISME Communications https://doi.org/10.1093/ismeco/ycae112 Fatima Ruiz-Blas Alexander Bartholomäus Sizhong Yang Dirk Wagner Cynthia Henny James M Russell Jens Kallmeyer Aurèle Vuillemin article leu2024 2024 07 10.1127/nos/2024/0803 Newsletters on Stratigraphy 57 Schweizerbart Science Publishers

Stuttgart, Germany

257-282 3 http://dx.doi.org/10.1127/nos/2024/0803 Katharina Leu Christian Zeeden Arne Ulfers Mehrdad Sardar Abadi Mathias Vinnepand Micha Ruhl Stephen Hesselbo Thomas Wonik article Scarponi20241089 Article 2024 10.1093/gji/ggad470 Geophysical Journal International 236 1089 – 1105 2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85181769204&doi=10.1093%2fgji%2fggad470&partnerID=40&md5=282def27ec1d0a88ff43858c4a0792fe Cited by: 1; All Open Access, Hybrid Gold Open Access M. Scarponi J. Kvapil J. Plomerová S. Solarino G. Hetényi article Tenuta2024 Article 2024 10.1016/j.lithos.2024.107841 Lithos 488-489 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85207665138&doi=10.1016%2fj.lithos.2024.107841&partnerID=40&md5=3e01bf0f529a95bf6bcd90d554744a20 Cited by: 1; All Open Access, Hybrid Gold Open Access Stefano Tenuta Katy A. Evans Steven M. Reddy David W. Saxey Tommaso Tacchetto Denis Fougerouse Xiao Sun article WOS:001178154800006 Article 2024 10.1130/B36547.1 GEOLOGICAL SOCIETY OF AMERICA BULLETIN 136 GEOLOGICAL SOC AMER, INC 307-328 1-2 Bruno Daniel Leite Mendes Agnes Kontny Michael Poelchau Lennart A. Fischer Ksenia Gaus Katarzyna Dudzisz Bonny W. M. Kuipers Mark J. Dekkers article item_5025555 All datasets provided in the operational dataset (Heubeck et al., 2024) of the ICDP project BASE (ICDP 5069) consist of metadata, data and/or images. Here, a summary of explanations of the tables, data and images exported from the database of the project (mDIS BASE) are given and are complemented by additional information on data from measurements done in the laboratory prior to the sampling party. Finally, the sampling data from the first two sampling parties are added. Some basic definitions of identifiers used in ICDP, depths corrections and measurements are also introduced. The BASE (Barberton Archean Surface Environments) scientific drilling project focused on recovering unweathered continuous core through strata of the Paleoarchean Moodies Group (ca. 3.2 Ga), central Barberton Greenstone Belt (BGB), South Africa. They comprise some of the oldest well-preserved sedimentary strata on Earth, deposited within only a few million years in alluvial, fluvial, coastal-deltaic, tidal, and prodeltaic settings; they represent a very-high-resolution record of Paleoarchean surface conditions and processes. Moodies Group strata consist of polymict conglomerates, widespread quartzose, lithic and arkosic sandstones, siltstones, shales, and rare BIFs and jaspilites, interbedded with tuffs and several thin lavas. This report describes operations from preparations to the sampling workshop and complements the related scientific report. Eight inclined boreholes between 280 and 495 m length, drilled during November 2021 through July 2022, obtained a total of 2903 m of curated core of variable quality through steeply to subvertically dipping, in part overturned stratigraphic sections. All drilling objectives were reached. Boreholes encountered a variety of conglomerates, diverse and abundant, mostly tuffaceous sandstones, rhythmically laminated shale-siltstone and banded-iron formations, and several horizons of early-diagenetic sulfate concretions. Oxidative weathering reached far deeper than expected; fracturing was more intense, and BIFs and jaspilites were thicker than anticipated. Two km-long mine adits and a water tunnel, traversing four thick stratigraphic sections within the upper Moodies Group in the central BGB, were also sampled. All boreholes were logged by geophysical instruments. Core was processed (oriented, slabbed, photographed, described, and archived) in a large, publicly accessible hall in downtown Barberton. An exhibition provided background explanations for visitors and related the drilling objectives to the recently established Barberton-Makhonjwa Mountains World Heritage Site. A substantial education, outreach and publicity program addressed the information needs of the local population and of local and regional stakeholders. ICDP Dataset 2024 eng 10.5880/ICDP.5069.001 International Continental Scientific Drilling Program, GFZ German Research Centre for Geosciences International Continental Scientific Drilling Program, GFZ German Research Centre for Geosciences International Continental Scientific Drilling Program, GFZ German Research Centre for Geosciences GFZ data services

Potsdam

C. Heubeck N. Beukes M. Homann E. J. Javaux T. Kakegawa S. Lalonde P. Mason M. Tice P. Mashele D. Paprika C. Rippon Rodney Tucker Ryan Tucker V. Ndazamo A. Christianson Cindy Kunkel article item_5025554 The BASE (Barberton Archean Surface Environments) scientific drilling project focused on recovering unweathered continuous core through strata of the Paleoarchean Moodies Group (ca. 3.2 Ga), central Barberton Greenstone Belt (BGB), South Africa. They comprise some of the oldest well-preserved sedimentary strata on Earth, deposited within only a few million years in alluvial, fluvial, coastal-deltaic, tidal, and prodeltaic settings and represent a very-high-resolution record of Paleoarchean surface conditions and processes. Moodies Group strata consist of polymict conglomerates, widespread quartzose, lithic and arkosic sand-stones, siltstones, shales, and rare BIFs and jaspilites, interbedded with tuffs and several thin lavas. This report describes operations from preparations to the sampling workshop and complements the related scientific report. Eight inclined boreholes between 280 and 495 m length, drilled during November 2021 through July 2022, obtained a total of 2903 m of curated core of variable quality through steeply to subvertically dipping, in part overturned stratigraphic sections. All drilling objec-tives were reached. Boreholes encountered a variety of conglomerates, diverse and abun-dant, mostly tuffaceous sandstones, rhythmically laminated shale-siltstone and banded-iron formations, and several horizons of early-diagenetic sulfate concretions. Oxidative weather-ing reached far deeper than expected; fracturing was more intense, and BIFs and jaspilites were thicker than anticipated. Two km-long mine adits and a water tunnel, traversing four thick stratigraphic sections within the upper Moodies Group in the central BGB, were also sampled. All boreholes were logged by geophysical instruments. Core was processed (ori-ented, slabbed, photographed, described, and archived) in a large, publicly accessible hall in downtown Barberton. An exhibition provided background explanations for visitors and relat-ed the drilling objectives to the recently established Barberton-Makhonjwa Mountains World Heritage Site. A substantial education, outreach and publicity program addressed the information needs of the local population and of local and regional stakeholders. ICDP Operational Report 2024 eng 10.48440/ICDP.5069.001 International Continental Scientific Drilling Program, GFZ German Research Centre for Geosciences International Continental Scientific Drilling Program, GFZ German Research Centre for Geosciences GFZ data services

Potsdam

74 C. Heubeck N. Beukes M. Homann E. J. Javaux T. Kakegawa S. Lalonde P. Mason M. Tice P. Mashele D. Paprika C. Rippon Rodney Tucker Ryan Tucker V. Ndazamo A. Christianson Cindy Kunkel article Rapprich2024113 The sequence of alkaline basaltic lavas and associated pyroclastic deposits that fill Bažina maar in western Bohemia is transected by a vein of apatite-dominated rock revealed in the S4 borehole. Aside from solid vein fill, apatite also impregnates a significant part of the drilled volcanic sequence. In the main body (depth 60.00–66.60 m), apatite occurs in two texturally distinct types: common cauliflower-type apatite (type 1) is transected by veinlets of coarser (0.2 mm long) apatite crystals (type 2). Both types have grown into open spaces suggesting precipitation from fluids rather than crystallization from melt, which is consistent with generally low trace element contents with slight enrichment in Cs, Sr, U and Pb. Relative to other local Plio-Pleistocene volcanic rocks, apatite vein-fill is shifted in87Sr/86Sr towards more radiogenic values (0.7053–0.7054). This suggests that fluids carrying mantle-derived ions mixed with groundwater interacting with granitic country-rock, as also evidenced by the purely crustal character of noble gases trapped in apatite. Unlike the mofettes occurring along the Mariánské Lázně Fault on the eastern margin of the Cheb Basin, the4He/3He ratios from Bažina apatite do not indicate mantle noble gas contribution. According to our model, the originally Sr–P-rich fluids with low87Sr/86Sr mixed with Cs–U-enriched groundwater circulating in country-rock granites with radiogenic 87 Sr/86Sr. Therefore, present-day CO2 outgassing through mofettes related mainly to the Mariánské Lázně Fault (eastern margin of the Cheb Basin) is likely independent of, and unrelated to, volcanism of the Cheb–Domažlice Graben. © 2024, Czech Geological Survey. All rights reserved. Article 2024 10.3190/jgeosci.392 Journal of Geosciences (Czech Republic) 69 Czech Geological Survey 113 – 127 2 Czech Republic; apatite; enrichment; igneous geochemistry; maar; noble gas; penetration; Pleistocene; precipitation (chemistry); strontium isotope; volcaniclastic deposit https://www.scopus.com/inward/record.uri?eid=2-s2.0-85202567467&doi=10.3190%2fjgeosci.392&partnerID=40&md5=f7345350702859456751e61d5ad6b7a5 Cited by: 0 Vladislav Rapprich Tomáš Vylita Kata Molnár John M. Hora Zsolt Benkó Michal Čurda Tomáš Magna Magdaléna Koubová Ondřej Pour Pavla Hrubcová Tomáš J. Fischer article Kitoga2024 Article 2024 10.1016/j.chemgeo.2024.122407 Chemical Geology 670 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85205665959&doi=10.1016%2fj.chemgeo.2024.122407&partnerID=40&md5=dc9dc460807a2a3b8daf470656a97084 Cited by: 0; All Open Access, Hybrid Gold Open Access L.S. Kitoga D. Zakharov J. Marin-Carbonne M. Boyet J.-F. Moyen T. Di Rocco A. Pack N. Olivier G. Stevens article Robinson202447 The release of over 4500 Gt (gigatonnes) of carbon at the Paleocene–Eocene boundary provides the closest geological analog to modern anthropogenic CO2 emissions. The cause(s) of and responses to the resulting Paleocene–Eocene Thermal Maximum (PETM) and attendant carbon isotopic excursion (CIE) remain enigmatic and intriguing despite over 30 years of intense study. CIE records from the deep sea are generally thin due to its short duration and slow sedimentation rates, and they are truncated due to corrosive bottom waters dissolving carbonate sediments. In contrast, PETM coastal plain sections along the US mid-Atlantic margin are thick, generally having an expanded record of the CIE. Drilling here presents an opportunity to study the PETM onset to a level of detail that could transform our understanding of this important event. Previous drilling in this region provided important insights, but existing cores are either depleted or contain stratigraphic gaps. New core material is needed for well-resolved marine climate records. To plan new drilling, members of the international scientific community attended a multi-staged, hybrid scientific drilling workshop in 2022 designed to maximize not only scientifically and demographically diverse participation but also to protect participants’ health and safety during the global pandemic and to reduce our carbon footprint. The resulting plan identified 10 sites for drill holes that would penetrate the Cretaceous–Paleogene (K–Pg) boundary, targeting the pre-onset excursion (POE), the CIE onset, the rapidly deposited Marlboro Clay that records a very thick CIE body, and other Eocene hyperthermals. The workshop participants developed several primary scientific objectives related to investigating the nature and the cause(s) of the CIE onset as well as the biotic effects of the PETM on the paleoshelf. Additional objectives focus on the evidence for widespread wildfires and changes in the hydrological cycle, shelf morphology, and sea level during the PETM as well as the desire to study both underlying K–Pg sediments and overlying post-Eocene records of extreme hyperthermal climate events. All objectives address our overarching research question: what was the Earth system response to a rapid carbon cycle perturbation? © Author(s) 2024. Conference paper 2024 10.5194/sd-33-47-2024 Scientific Drilling 33 Copernicus Publications 47 – 65 1 Carbon footprint; Coremaking; Earth system models; Infill drilling; Stratigraphy; Anthropogenics; Carbon injections; CO 2 emission; Coastal plain; Deep sea; Ecosystem response; Paleocene-Eocene boundaries; Paleocene-eocene thermal maximums; Paleogene; Short durations; Sea level https://www.scopus.com/inward/record.uri?eid=2-s2.0-85189492609&doi=10.5194%2fsd-33-47-2024&partnerID=40&md5=250ab95af544d446605e44134e4d580f Cited by: 1; All Open Access, Gold Open Access Marci M. Robinson Kenneth G. Miller Tali L. Babila Timothy J. Bralower James V. Browning Marlow J. Cramwinckel Monika Doubrawa Gavin L. Foster Megan K. Fung Sean Kinney Maria Makarova Peter P. McLaughlin Paul N. Pearson Ursula Röhl Morgan F. Schaller Jean M. Self-Trail Appy Sluijs Thomas Westerhold James D. Wright James C. Zachos article Zhang2024 Article 2024 10.1016/j.palaeo.2024.112214 Palaeogeography, Palaeoclimatology, Palaeoecology 647 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85192315585&doi=10.1016%2fj.palaeo.2024.112214&partnerID=40&md5=325142193f76767b3865d719c95143bb Cited by: 3 Li Zhang Yongdong Wang Micha Ruhl Emma Blanka Kovács Yuanyuan Xu Yanbin Zhu Ning Lu Hongyu Chen article Zhao2024 Article 2024 10.1016/j.epsl.2023.118507 Earth and Planetary Science Letters 626 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85179136507&doi=10.1016%2fj.epsl.2023.118507&partnerID=40&md5=ce4c430726a63bc6f3357c2da3a78006 Cited by: 3 Jiawei Zhao Xiang Zhang Long Xiao Aaron J. Cavosie Nicholas E. Timms Alexander Nemchin Zhiyong Xiao Wentao Hu Yuqing Chang Jinfu Shu Qi He Shanrong Zhao Jiang Wang Jiannan Zhao article Grant2024 Here we present a method for using the spatial x–y coordinate of an image cropped from the cylindrical surface of digital 3D drill core images and demonstrate how this spatial metadata can be used to improve unsupervised machine learning performance. This approach is applicable to any data set with known spatial context, however, here it is used to classify 400 m of drillcore imagery into 12 distinct classes reflecting the dominant rock types and alteration features in the core. We modified two unsupervised learning models to incorporate spatial metadata and an average improvement of 25% was achieved over equivalent models that did not utilize metadata. Our semi-supervised workflow involves unsupervised network training followed by semi-supervised clustering where a support vector machine uses a subset of M expert labeled images to assign a pseudolabel to the entire data set. Fine-tuning of the best performing model showed an f1 (macro average) of 90%, and its classifications were used to estimate bulk fresh and altered rock abundance downhole. Validation against the same information gathered manually by experts when the core was recovered during the Oman Drilling Project revealed that our automatically generated data sets have a significant positive correlation (Pearson's r of 0.65–0.72) to the expert generated equivalent, demonstrating that valuable geological information can be generated automatically for 400 m of core with only ∼24 hr of domain expert effort. © 2024 The Authors. Earth and Space Science published by Wiley Periodicals LLC on behalf of American Geophysical Union. Article 2024 10.1029/2023EA003220 Earth and Space Science 11 John Wiley and Sons Inc 3 Oman; coordinate; data set; drilling; image analysis; machine learning; rock; satellite imagery; support vector machine https://www.scopus.com/inward/record.uri?eid=2-s2.0-85187869703&doi=10.1029%2f2023EA003220&partnerID=40&md5=ab7ef4b1f846866dfd08f48dec510521 Cited by: 1; All Open Access, Gold Open Access Lewis J. C. Grant Miquel Massot-Campos Rosalind M. Coggon Blair Thornton Francesca C. Rotondo Michelle Harris Aled D. Evans Damon A. H. Teagle article Ageli2024 Article 2024 10.1016/j.jglr.2023.09.001 Journal of Great Lakes Research 50 3 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85171973485&doi=10.1016%2fj.jglr.2023.09.001&partnerID=40&md5=d134f86bcff08204cd9cb420f17e14f1 Cited by: 1 Mariam K. Ageli Paul B. Hamilton Andrew J. Bramburger James Russell Hendrik Vogel Satria Bijaksana G. Douglas Haffner article Lipus2024 Article 2024 10.1186/s40793-024-00651-9 Environmental Microbiome 19 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85212844735&doi=10.1186%2fs40793-024-00651-9&partnerID=40&md5=4a52e594919b818c2f50d86a3e38ad67 Cited by: 0; All Open Access, Gold Open Access Daniel Lipus Zeyu Jia Megan Sondermann Robert Bussert Alexander Bartholomäus Sizhong Yang Dirk Wagner Jens Kallmeyer article Jackson20243527 Characterization of 2017 drill core samples from Surtsey, an oceanic island produced by 1963–1967 eruptions in the offshore extension of Iceland’s east rift zone, reveals highly heterogeneous microstructural, physical, and mechanical properties in subaerial, submarine, and subseafloor basaltic deposits. The connected porosity varies from 42% in weakly consolidated lapilli tuff in a submarine inflow zone to 21% in strongly lithified lapilli tuff in upper subseafloor deposits near the explosively excavated conduit. Permeability, however, varies over six orders of magnitude, from 10−18 m2 to 10−13 m2. Uniaxial compressive strength, P-wave velocity, and thermal conductivity are also highly variable: 10–70 MPa, 1.48–3.74 km·s−1, and 0.472–0.862 W·m−1·K−1, respectively. Synchrotron X-ray microdiffraction analyses integrated with major-element geochemistry and quantitative X-ray powder diffraction analyses describe the initial alteration of fresh glass, incipient consolidation of a fine-ash matrix, and partial closure of pores with mineral cements. Permeability, micromechanical, and thermal property modeling highlight how porosity and pore size in eruptive fabrics—modified through diverse cementing microstructures—influence the physical properties of the pyroclastic deposits. Borehole temperatures, 25–141 °C (measured from 1980 to 2018), do not directly correlate with rock strength properties; rather, the abundance and consolidation of a binding fine-ash matrix appears to be a primary factor. Analytical results integrated with archival data from 1979 drill core samples provide reference parameters for geophysical and heat transfer studies, the physical characteristics of pyroclastic deposits that lithify on a decadal scale, and the stability and survival of oceanic islands over time. For permission to copy, contact editing@geosociety.org © 2024 Geological Society of America Article 2024 10.1130/B37037.1 Bulletin of the Geological Society of America 136 Geological Society of America 3527 – 3552 9-10 Iceland; Surtsey; Basalt; Clay alteration; Drilling rigs; Pore size; Scale (deposits); Submarine geology; Underwater mineral resources; X ray diffraction analysis; Drill core; Fine ashes; Icelands; matrix; Mechanical; Oceanic islands; Property; Pyroclastic deposits; Sub-seafloor; Thermal; basalt; decadal variation; mechanical property; pyroclastic deposit; underwater environment; X-ray diffraction; Compressive strength https://www.scopus.com/inward/record.uri?eid=2-s2.0-85187454396&doi=10.1130%2fB37037.1&partnerID=40&md5=668aac63a23b6f1653690ba0a543a6e2 Cited by: 3; All Open Access, Green Open Access M.D. Jackson M.J. Heap G. Vola M. Ardit J.M. Rhodes J.G. Peterson N. Tamura M.T. Gudmundsson article RN96 2024 10.22498/pages.32.2.124 Past Global Changes Magazine 32 124-125 2 Camille Thomas J. Wang J. Berg T. Haberzettl R. Kipfer H. Vogel article RN96 2024 10.22498/pages.32.2.88 Past Global Changes Magazine 32 88-89 2 Christian Zeeden Huaichun Wu Qiang Fang Simona Pierdominici Mathias Vinnepand M. Sardar Abadi Arne Ulfers article RN96 2024 10.22498/pages.32.2.88 Past Global Changes Magazine 32 88-89 2 Christian Zeeden Huaichun Wu Qiang Fang Simona Pierdominici Mathias Vinnepand M. Sardar Abadi Arne Ulfers article Wang2024511 Over the past century global temperatures continue to rise, and the Earth may enter a greenhouse period in the future with no ice at the poles. The Cretaceous was a typical greenhouse period in deep time, and thus understanding the Cretaceous climate is significant for interpreting past climate changes and predicting future trends. The International Continental Scientific Drilling Project of the Songliao Basin is the world's first continental scientific drilling project to penetrate the Cretaceous continental strata within the framework of the ICDP. This project is aimed to investigate Cretaceous terrestrial climate and environmental changes, and to explore the mechanisms of massive terrestrial organic matter accumulation and enrichment. Spanning 16 years, this project achieves a continuous and complete 8187-meter core with a recovery rate exceeding 97%, establishes a high-precision chronostratigraphic framework for the Cretaceous continental strata in the Songliao Basin, reconstructs multi-temporal-scale terrestrial climate cycles and climate events during the Cretaceous period, reveals the mechanisms of Cretaceous sea-level fluctuations, and confirms marine incursion events in the Songliao Basin. The International Continental Scientific Drilling Project of the Songliao Basin has promoted global collaboration among geologists to study Cretaceous greenhouse climates, leading to a series of high-impact research achievements. It has provided crucial scientific support for the sustainable development of oil and gas exploration in the Songliao Basin, and has generated significant social benefits and substantial international and domestic influence. The International Continental Scientific Drilling Project of the Songliao Basin represents a milestone stage in exploring deep-time Earth, and it is foreseeable that in the future, humans will continue enhancing the understanding of deep-time climate and environmental evolution with the aid of scientific drilling. © 2024 Science Frontiers editorial department. All rights reserved. Article 2024 10.13745/j.esf.sf.2024.1.4-en Earth Science Frontiers 31 Science Frontiers editorial department 511 – 534 1 Climate change; Earth (planet); Infill drilling; Petroleum prospecting; Sea level; Sustainable development; Basin; Chronostratigraphic framework; Continental scientific drillings; Cretaceous; Drilling projects; International continental scientific drilling program; Marine incursion; Marine incursion event; Pa-leoclimate; Songliao; Greenhouses https://www.scopus.com/inward/record.uri?eid=2-s2.0-85188158333&doi=10.13745%2fj.esf.sf.2024.1.4-en&partnerID=40&md5=e54f11e8127bddbf5201803396b0090f Cited by: 3 Chengshan Wang Yuan Gao Pujun Wang Huaichun Wu Qingtian Lü Yongyi Zhu Xiaoqiao Wan Changchun Zou Yongjian Huang Youfeng Gao Dangpeng Xi Wenshi Wang Huaiyu He Zihui Feng Guang Yang Chenglong Deng Laiming Zhang Tiantian Wang Bin Hu Liwei Cui Cheng Peng Enxiao Yu He Huang Liu Yang Zhengxuan Wu article Giaccio2024249 Article 2024 10.5194/sd-33-249-2024 Scientific Drilling 33 249 – 266 2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85213425043&doi=10.5194%2fsd-33-249-2024&partnerID=40&md5=02626eafc933b015c60002a9bc587f3c Cited by: 1; All Open Access, Gold Open Access Biagio Giaccio Bernd Wagner Giovanni Zanchetta Adele Bertini Gian Paolo Cavinato Roberto De Franco Fabio Florindo David A. Hodell Thomas A. Neubauer Sébastien Nomade Alison Pereira Laura Sadori Sara Satolli Polychronis C. Tzedakis Paul Albert Paolo Boncio Cindy De Jonge Alexander Francke Christine Heim Alessia Masi Marta Marchegiano Helen M. Roberts Anders Noren Vitor Azevedo Leoan Clarke Giulia Cheli Edi Chiarini Angelo Cipriani Sandro Conticelli Deniz Cukur Grisha Fedorov Luigi Improta Niklas Leicher Martin Danisik Julieta Massaferro Elizabeth Niespolo Jose E. Ortiz Menendez Alice Paine Sofia Pechlivanidou Ivan Razum Eleonora Regattieri Camille Thomas Mathias Vinnepand Dustin White article Sayyadi2024 Article 2024 10.1016/j.jvolgeores.2024.108096 Journal of Volcanology and Geothermal Research 451 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85193858209&doi=10.1016%2fj.jvolgeores.2024.108096&partnerID=40&md5=1777e1d6005374baed241702b1e140c1 Cited by: 0; All Open Access, Green Open Access, Hybrid Gold Open Access Sara Sayyadi Magnus T. Gudmundsson James D.L. White Thorsteinn Jónsson Maxwell C. Brown Marie D. Jackson article Wang2024 Article 2024 10.1016/j.marpetgeo.2024.107042 Marine and Petroleum Geology 168 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85200148612&doi=10.1016%2fj.marpetgeo.2024.107042&partnerID=40&md5=00f4deff696e4eb5f23ce7786cd1513c Cited by: 0 Pujun Wang Zhuolong Yang Youfeng Gao Xuejiao Qu Haibo Liu Yongkang Yin Chengshan Wang Xiaoqiao Wan Shumin Chen article Martínez-Abarca2024 Article 2024 10.1016/j.quascirev.2024.108985 Quaternary Science Reviews 344 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85206321128&doi=10.1016%2fj.quascirev.2024.108985&partnerID=40&md5=ff7b25c6b15689d2d57e662497e0457a Cited by: 0; All Open Access, Hybrid Gold Open Access Rodrigo Martínez-Abarca Liseth Pérez Thorsten Bauersachs Frederik Schenk Steffen Kutterolf Mark Brenner Thomas Guilderson Alex Correa-Metrio Flavio S. Anselmetti Robert Brown Daniel Ariztegui Laura Macario-González Esmeralda Cruz-Silva Juan Carlos Beltran-Martinez Mark Bush Mona Stockhecke Jason Curtis Antje Schwalb article Li2024 Abstract The first borehole 5071_1_B of the ICDP-Drilling the Ivrea-Verbano zonE (DIVE) project in Italy, which intersects the Massone antiform, provides a unique opportunity to integrate downhole geophysical measurements with observations from 100% recovered drill core in rarely drilled lithologies. The objective of this study is to petrophysically and structurally characterize the rock mass and constrain factors influencing the seismic velocity in the lower continental crust. A comprehensive data set, comprising core, well log and vertical seismic profiling data, was collected. The structural analysis indicates that the axial plane of the intersected tightly folded antiform is slightly tilted at the borehole location and thus the borehole intersects the hinge zone at the top and its limb in the lower part of 5071_1_B. Numerous open natural fractures with variable dips and two dominant dip azimuthal orientations are identified along the borehole, which affect the electrical and acoustic properties. The velocities at the core, well log and seismic scale are consistent but lower than intrinsic seismic velocities of the lower continental crust, since they are not only affected by fractures but also by micro cracks at the 5071_1_B in situ conditions. A systematic lithology correlation is not evident for these properties. However, a cluster analysis of gamma ray and magnetic susceptibility logs shows an excellent agreement with the logged core lithologies in the presence of remarkable spatial variability. Furthermore, the main lithologies are grouped into three distinct clusters, suggesting two types of kinzigites with distinct magnetic and radiogenic properties. Article 2024 10.1029/2024GC011707 Geochemistry, Geophysics, Geosystems 25 e2024GC011707 12 rock physics, well logging, Ivrea-Verbano zone, rock mass characterization, lower continental crust https://www.scopus.com/inward/record.uri?eid=2-s2.0-85212442154&doi=10.1029%2f2024GC011707&partnerID=40&md5=de71304bfdd073c26bd4c1f6c25fa625 Cited by: 2; All Open Access, Gold Open Access J. Li E. Caspari A. Greenwood S. Pierdominici K. Lemke M. Venier J. Kück L. Baron M. Pistone B. Petri L. Ziberna G. Hetényi article Koeberl2024 Article 2024 10.1016/j.precamres.2024.107511 Precambrian Research 411 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85199011245&doi=10.1016%2fj.precamres.2024.107511&partnerID=40&md5=22998621e16fab640511fd8ef4648ec4 Cited by: 0; All Open Access, Hybrid Gold Open Access Christian Koeberl Toni Schulz Matthew S. Huber article Qin2024168 Article 2024 10.12143/j.ztgc.2024.04.005 Drilling Engineering 51 31 – 37 4 H. Zhang L. Cao W. Wang J. Yan S. Shi Y. Wang Q. Xue article RN96 2024 10.22498/pages.32.2.104 Past Global Changes Magazine 32 104-105 2 Y. Sun Y. Song L. Ai X. Liu Z. An article Martin-Jones2024 Regional tephrostratigraphic frameworks connect palaeoclimate, archaeological and volcanological records preserved in soils or lake sediments via shared volcanic ash (tephra) layers. In eastern Africa, tracing of tephra isochrons between geoarchaeological sequences is an established chronostratigraphic approach. However, to date, few long tephra records exist from sites with continuous depositional sequences, such as lake sediments, which offer the potential to connect local and discontinuous sequences at the regional scale. Long lake sediment sequences may also capture more complete eruptive histories of understudied volcanic centres. Here, we present and date the tephrostratigraphic record of a >250,000-year (>250-kyr) continuous sediment sequence extracted from Lake Chala, a crater lake on the Kenya-Tanzania border near Mt Kilimanjaro. Single-grain glass major and minor element analyses of visible and six cryptotephra layers reveal compositions ranging from mafic foidites and basanites to more evolved tephri-phonolites, phonolites, trachytes and a single rhyolite. Of these, nine are correlated to scoria cone eruptions of neighbouring Mt Kilimanjaro or the Chyulu volcanic field ∼60 km to the north; seven are correlated to phonolitic eruptions of Mt Meru, ∼100 km to the west; and four to voluminous trachytic eruptions of Central Kenyan Rift (CKR) volcanoes located ∼350 km to the north. The only rhyolitic tephra layer, a cryptotephra, correlates to the 73.7-ka BP (before present, taken as 1950 CE) Younger Toba Tuff (YTT) from Sumatra. Two of the CKR tephra layers provide direct ties with terrestrial sequences relevant to Middle Stone Age archaeology of the eastern Lake Victoria basin in Kenya. Absolute age estimates obtained by direct 40Ar/39Ar dating of 10 tephra layers are combined with six 210Pb and 162 14C dates covering the last 25-kyr and the well-constrained known age of the YTT to build a first absolute chronology for the full Lake Chala sediment sequence. The uninterrupted >250-kyr Lake Chala sedimentary archive represents a unique tephrostratotype sequence for eastern Africa, optimising the chronological value of tephra correlations in regional palaeoenvironmental, archaeological and volcanological research. Further study of cryptotephra in the Lake Chala sequence and additional geochemical characterisation and dating of ancient volcanic eruptions from nearby and further afield may eventually produce a regionally connected and detailed tephrostratigraphic framework for eastern equatorial Africa. © 2024 The Authors Article 2024 10.1016/j.quascirev.2023.108476 Quaternary Science Reviews 326 Elsevier Ltd Africa; East African Lakes; Lake Victoria; Argon; Geochemistry; Geochronology; Sediments; Volcanoes; Africa; Argon dating; East African Rift; East african rift system; Holocenes; Lake chala; Lake sediments; Palaeoclimate; Pleistocene; Rift systems; Tephrochronology; archaeology; chronology; crater lake; geochemistry; geochronology; Holocene; lacustrine deposit; Mesolithic; paleoclimate; tephrochronology; volcanic ash; Lakes https://www.scopus.com/inward/record.uri?eid=2-s2.0-85182891635&doi=10.1016%2fj.quascirev.2023.108476&partnerID=40&md5=7a433adf9112ece8ad25f1b4ba150a53 Cited by: 0; All Open Access, Hybrid Gold Open Access Catherine Martin-Jones Christine S. Lane Maarten Blaauw Darren F. Mark Dirk Verschuren Thijs Meeren Maarten Van Daele Hannah Wynton Nick Blegen Mary Kisaka Melanie J. Leng Philip Barker article Wang2024377 Article 2024 10.13745/j.esf.sf.2023.11.38 Earth Science Frontiers 31 377 – 390 2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85193901712&doi=10.13745%2fj.esf.sf.2023.11.38&partnerID=40&md5=196f9973e2db0b04b838322e2d5f83cf Cited by: 0 Bin Wang Dongsheng Sun Awei Li Yuehui Yang Qunce Chen article sd-33-207-2024 2024 10.5194/sd-33-207-2024 Scientific Drilling 33 207--218 2 A. Foubert D. Keir B. Atnafu T. Kidane Consortium article Lozhkin2024 Palynological analysis of sediments from El'gygytgyn Lake document vegetation changes in the Eastern Arctic from early marine isotope stage (MIS) 74 to late MIS 80 (c.2.1–1.9 MA) and close the last remaining gap in the El'gygytgyn pollen record. Cooler climates were characterized by a mix of Larix forest-tundra, shrub Betula tundra, and herb-dominated communities. During interglaciations, Larix forests with tree Betula and Alnus, and perhaps with a minor component of Picea and tree Pinus, characterized areas that today are tundra. These forests included a rich shrub understory of Betula, Duschekia, Salix, and Pinus pumila. Although MIS 77 has been considered a “super” interglaciation, the data do not indicate that this stage was exceptionally warm. Interstadial conditions are denoted by pollen assemblages that indicate the regional vegetation was dominated by Larix forest -tundra and an absence of Pinus pumila. The palynological results from this Early Pleistocene interval demonstrate the need to: 1) modify the El'gygytgyn age model; 2) reevaluate the relationship of sediment facies to climate change; and 3) reconsider the occurrence and/or definition of “super” interglaciations. © 2023 Article 2024 10.1016/j.revpalbo.2024.105094 Review of Palaeobotany and Palynology 324 Elsevier B.V. Arctic; Chukchi; Elgygytgyn Lake; Russian Federation; climate change; glaciation; interglacial; isotopic analysis; marine isotope stage; paleobotany; palynology; Pleistocene; pollen; vegetation cover https://www.scopus.com/inward/record.uri?eid=2-s2.0-85188703790&doi=10.1016%2fj.revpalbo.2024.105094&partnerID=40&md5=7860df4b8eeffc6032507dbaa1a2955d Cited by: 0 Anatoly V. Lozhkin Patricia M. Anderson Julia A. Korzun Ekaterina Yu. Nedorubova article Lodowski202487 Article 2024 10.7306/VJ.22.6 Volumina Jurassica 22 87 – 116 https://www.scopus.com/inward/record.uri?eid=2-s2.0-105006886593&doi=10.7306%2fVJ.22.6&partnerID=40&md5=a42ebfc658ec5c0a3cad564aa6e868ff Cited by: 0 Damian G. Lodowski Mathieu Martinez Stephen P. Hesselbo Marta Hodbod Melanie J. Leng Grzegorz Pieńkowski Paweł Brański Robyn Pointer article Shervais20244252 Article 2024 10.1130/B37413.1 Bulletin of the Geological Society of America 136 4252 – 4262 9-10 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85203428546&doi=10.1130%2fB37413.1&partnerID=40&md5=7b5eb80263bc760efed910071a7bcaec Cited by: 0 John W. Shervais Katherine E. Potter article RN96 2024 10.22498/pages.32.2.76 Past Global Changes Magazine 32 76-77 2 A. C. G. Henderson J. Wang L. Zhu T. Haberzettl J. Ju H. Vogel L. Clarke article Magson2024 Article 2024 10.1007/s00410-024-02155-8 Contributions to Mineralogy and Petrology 179 7 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85196707147&doi=10.1007%2fs00410-024-02155-8&partnerID=40&md5=8e3e20b8dbbbc604e12dce59c28848d3 Cited by: 1; All Open Access, Hybrid Gold Open Access Justine Magson Frederick Roelofse Grant Bybee Robert Bolhar article RN96 2024 10.22498/pages.32.2.96 Past Global Changes Magazine 32 96-97 2 Nicolas Waldmann M. Stein DSDDP Scientific Party article Lehnert2024134 Article 2024 10.3176/earth.2024.13 Estonian Journal of Earth Sciences 73 134 – 140 2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85208604776&doi=10.3176%2fearth.2024.13&partnerID=40&md5=1e9be94c8232875533d7650b143f47f5 Cited by: 1; All Open Access, Gold Open Access Oliver Lehnert Bjarne Almqvist Mark Anderson Jenny Andersson Simon Cuthbert Mikael Calner Isabel Carter Riccardo Callegari Christopher Juhlin Henning Lorenz Claudio Madonna Guido Meinhold Luca Menegon Iwona Klonowska Christophe Pascal Markus Rast Nick M. W. Roberts Jonas B. Ruh Grzegorz Ziemniak article Hofmann2024 Article 2024 10.1016/j.precamres.2024.107584 Precambrian Research 414 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85206607366&doi=10.1016%2fj.precamres.2024.107584&partnerID=40&md5=cd37089721556ddea30f3ce99d259349 Cited by: 1; All Open Access, Hybrid Gold Open Access A. Hofmann article Buechi2024 Article 2024 10.1016/j.quascirev.2024.108970 Quaternary Science Reviews 344 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85205137314&doi=10.1016%2fj.quascirev.2024.108970&partnerID=40&md5=5b060323e5498409c4e14bf654096184 Cited by: 0; All Open Access, Hybrid Gold Open Access Marius W. Buechi Angela Landgraf Herfried Madritsch Daniela Mueller Maria Knipping Franziska Nyffenegger Frank Preusser Sebastian Schaller Michael Schnellmann Gaudenz Deplazes article Nisson2024 Article 2024 10.1093/ismeco/ycae138 ISME Communications 4 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-105009719003&doi=10.1093%2fismeco%2fycae138&partnerID=40&md5=66be5f2b6107918f60e24c8869872a0e Cited by: 1; All Open Access, Gold Open Access, Green Open Access Devan M. Nisson Thomas L. Kieft Julio Castillo Scott M. Perl Tullis C. Onstott article Qin2024168 Article 2024 10.12143/j.ztgc.2024.04.003 Drilling Engineering 51 14-22 04 Z. Zhang H. Ran Y. Zhang S. Chen D. Liu article RN97 2024 10.1093/femsec/fiae140 FEMS Microbiol Ecol https://www.ncbi.nlm.nih.gov/pubmed/39384533 A. Vuillemin F. Ruiz-Blas S. Yang A. Bartholomaus C. Henny J. Kallmeyer conference Pálsson20242974 Conference paper 2024 Transactions - Geothermal Resources Council 48 2974 – 2983 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85214263568&partnerID=40&md5=e291566c1e82137d92826803043f2448 Cited by: 0 Bjarni Pálsson article RN96 Article 2024 10.1038/s41467-024-47921-1 Nat Commun 15 https://www.ncbi.nlm.nih.gov/pubmed/38714681 M. H. Trauth A. Asrat M. L. Fischer P. O. Hopcroft V. Foerster S. Kaboth-Bahr K. Kindermann H. F. Lamb N. Marwan M. A. Maslin F. Schaebitz P. J. Valdes article Leong2024 Article 2024 10.1016/j.lithos.2024.107828 Lithos 488-489 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85205934617&doi=10.1016%2fj.lithos.2024.107828&partnerID=40&md5=0db1de0876a160ffeb978217d610a58a Cited by: 0; All Open Access, Hybrid Gold Open Access James Andrew Leong Juan Carlos Obeso Thomas Sharp Everett Shock Peter Kelemen article Suzuki2024 Article 2024 10.1007/s00248-024-02434-8 Microbial Ecology 87 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85205527060&doi=10.1007%2fs00248-024-02434-8&partnerID=40&md5=fa08572ab8f00a84e4d6962a58e6750a Cited by: 2; All Open Access, Hybrid Gold Open Access Yohey Suzuki Susan J. Webb Mariko Kouduka Hanae Kobayashi Julio Castillo Jens Kallmeyer Kgabo Moganedi Amy J. Allwright Reiner Klemd Frederick Roelofse Mabatho Mapiloko Stuart J. Hill Lewis D. Ashwal Robert B. Trumbull article Fischer2024 Eastern Africa and Arabia were major hominin hotspots and critical crossroads for migrating towards Asia during the late Pleistocene. To decipher the role of spatiotemporal environmental change on human occupation and migration patterns, we remeasured the marine core from Meteor Site KL 15 in the Gulf of Aden and reanalyzed its data together with the aridity index from ICDP Site Chew Bahir in eastern Africa and the wet-dry index from ODP Site 967 in the eastern Mediterranean Sea using linear and nonlinear time series analysis. These analyses show major changes in the spatiotemporal paleoclimate dynamics at 400 and 150 ka BP (thousand years before 1950), presumably driven by changes in the amplitude of the orbital eccentricity. From 400 to 150 ka BP, eastern Africa and Arabia show synchronized wet-dry shifts, which changed drastically at 150 ka BP. After 150 ka BP, an overall trend to dry climate states is observable, and the hydroclimate dynamics between eastern Africa and Arabia are negatively correlated. Those spatio-temporal variations and interrelationships of climate potentially influenced the availability of spatial links for human expansion along those vertices. We observe positively correlated network links during the supposed out-of-Africa migration phases of H. sapiens. Furthermore, our data do not suggest hominin occupation phases during specific time intervals of humid or stable climates but provide evidence of the so far underestimated potential role of climate predictability as an important factor of hominin ecological competitiveness. © 2024 The Authors Article 2024 10.1016/j.qsa.2024.100174 Quaternary Science Advances 14 Elsevier Ltd https://www.scopus.com/inward/record.uri?eid=2-s2.0-85188696294&doi=10.1016%2fj.qsa.2024.100174&partnerID=40&md5=2b87a7d9c02be9c2e22ab24426d61b17 Cited by: 2; All Open Access, Gold Open Access Markus L. Fischer Philipp M. Munz Asfawossen Asrat Verena Foerster Stefanie Kaboth-Bahr Norbert Marwan Frank Schaebitz Wolfgang Schwanghart Martin H. Trauth article Schuster2024191 Article 2024 10.5194/sd-33-191-2024 Scientific Drilling 33 191 – 206 2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85197588168&doi=10.5194%2fsd-33-191-2024&partnerID=40&md5=19c59c48d224db0569eff0363c74d069 Cited by: 9; All Open Access, Gold Open Access, Green Open Access Bennet Schuster Lukas Gegg Sebastian Schaller Marius W. Buechi David C. Tanner Ulrike Wielandt-Schuster Flavio S. Anselmetti Frank Preusser article Pasiecznik20241612 Article 2024 10.1093/gji/ggae239 Geophysical Journal International 238 1612 – 1625 3 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85199217089&doi=10.1093%2fgji%2fggae239&partnerID=40&md5=48567ce345adf6497b52b04882eae8fa Cited by: 0; All Open Access, Hybrid Gold Open Access Damian Pasiecznik Andrew Greenwood Florian Bleibinhaus György Hetényi article WOS:001228045000001 2024 10.1021/acsomega.4c00832 ACS OMEGA 9 21097-21115 19 Shuangbiao Han Xin Du Yufei He Chengshan Wang Mengxia Huo Xiaoyan Mu Ye Wang Jie Huang Chenxin Zhang article Qin2024168 Article 2024 10.1016/j.gca.2024.09.031 Geochimica et Cosmochimica Acta 384 168 – 177 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85205439369&doi=10.1016%2fj.gca.2024.09.031&partnerID=40&md5=72bea26d383ebda34ae4af727085f4d6 Cited by: 0 Zheng Qin Jingao Liu Huan Cui Kurt O. Konhauser He Huang Dongtao Xu Yuan Gao Huaichun Wu Chengshan Wang article Wu2024431 Article 2024 10.13745/j.esf.sf.2024.1.22 Earth Science Frontiers 31 431 – 445 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85188175839&doi=10.13745%2fj.esf.sf.2024.1.22&partnerID=40&md5=2e2fae76adab60a9ba8914f6fee313ab Cited by: 2 Huaichun Wu Shan Li Chengshan Wang Runjian Chu Pujun Wang Yuan Gao Xiaoqiao Wan Huaiyu He Chenglong Deng Guang Yang Yongjian Huang Youfeng Gao Dangpeng Xi Tiantian Wang Qiang Fang Tianshui Yang Shihong Zhang article Hollaar20242795 Present-day fire frequency is related to a productivity-aridity gradient on regional and global scales. Optimum fire conditions occur at times of intermediate productivity and aridity, whereas fire is limited at the high productivity (moisture) and aridity (no fuel) endmembers. However, the current global fire activity pattern is reinforced by the predominant burning of grasslands. Here we test the intermediate fire-productivity hypothesis for a period on Earth before the evolution of grasses, the Early Jurassic, and explore the fire regime of two contrasting climatic states: the cooling of the Late Pliensbachian Event (LPE) and the warming of the Sinemurian-Pliensbachian Boundary (SPB). Palaeo-fire records are reconstructed from fossil charcoal abundance, and changes in the hydrological cycle are tracked via clay mineralogy, which allows inference of changes in fuel moisture status. Large fluctuations in the fossil charcoal on an eccentricity timescale indicate two modes of fire regime at the time. Wildfires were moisture-limited in a high-productivity ecosystem during eccentricity minima for both the SPB and the LPE. During eccentricity maxima fires increased, and an optimum fire window was reached, in which periodically greater seasonality in rainfall and temperatures led to intermediate states of productivity and aridity. The LPE experienced more extreme climatic endmembers compared to the SPB, with the fire regime edging closer to "moisture limitation"during eccentricity minima, and experienced more pronounced seasonality during eccentricity maxima, explained by the overall cooler climate at the time. This study illustrates that the intermediate-productivity gradient holds up during two contrasting climatic states in the Jurassic. © 2024 Copernicus Publications. All rights reserved. Article 2024 10.5194/bg-21-2795-2024 Biogeosciences 21 Copernicus Publications 2795 – 2809 11 aridity; grass; grassland; Jurassic; paleoecology; paleoenvironment; rainfall; seasonality; wildfire https://www.scopus.com/inward/record.uri?eid=2-s2.0-85196197724&doi=10.5194%2fbg-21-2795-2024&partnerID=40&md5=e9474fdfdb733225879ac7634a072059 Cited by: 0 Teuntje P. Hollaar Claire M. Belcher Micha Ruhl Jean-François Deconinck Stephen P. Hesselbo article Alexander2024 Article 2024 10.1029/2023EA003383 Earth and Space Science 11 5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85192465319&doi=10.1029%2f2023EA003383&partnerID=40&md5=82264c2d665c1720752de3073f2efb0c Cited by: 2 Amanda M. Alexander Simone Marchi Brandon C. Johnson Sean E. Wiggins David A. Kring article Firla2024 Overdeepened valleys are structures scoured into the underlying substrate by glaciers that have been subsequently filled with sediment, which recorded the environmental history of the adjacent landscape. Investigated here is an overdeepened structure that was formed beneath the Salzach Paleoglacier west of Freilassing, Bavaria (southern Germany). In a previous study, infinite infrared stimulated luminescence (IRSL) ages have been determined for the lower part of the core using a multi-grain approach. Applying single-grain feldspar luminescence dating allows to identify the unsaturated signals, previously masked by multi-grain signal averaging. Identification of the normally distributed leading edge in equivalent dose (De) distributions allows for the dismissal of low value De (LOVED) grains that appear to reflect underestimating outliers. Measurement of eleven samples distributed along the entire length of the core yielded two distinct age clusters, for which fading corrected IRSL50 and uncorrected pIRIR225 ages agree within uncertainties. Whereas the younger age cluster at the top of the sequence is attributed to Marine Isotope Stage (MIS) 3, the older age cluster is assigned to MIS 6. It is shown that single grain pIRIR measurements will allow to resolve the infill chronology of overdeepened structures in the Alps, at least for the last ca. 200 ka. Overall, the present study represents a further step towards understanding and handling complex De distributions often encountered in single grain feldspar luminescence dating. This contributes to better understand the frequently observed age offset between single grain and single-aliquot measurements. © 2024 The Authors Article 2024 10.1016/j.quageo.2024.101627 Quaternary Geochronology 85 Elsevier B.V. https://www.scopus.com/inward/record.uri?eid=2-s2.0-85205438388&doi=10.1016%2fj.quageo.2024.101627&partnerID=40&md5=c1865dfe53cad1339c1a660a57b57f25 Cited by: 0; All Open Access, Hybrid Gold Open Access Gustav Firla Christopher Lüthgens Stephanie Neuhuber Clemens Schmalfuss Ernst Kroemer Frank Preusser Markus Fiebig article Lazar2024 The application of geophysical methods in saline environments is limited in their ability to discern shallow subsurface geology and tectonics due to the high subsurface conductivity, which can play havoc with the geophysical signal. Recent changes in the hypersaline Dead Sea provided the opportunity to demonstrate the effectiveness and adequacy of the terrestrial frequency domain electromagnetic (henceforth FDEM) method in such settings. Since the International Continental Drilling Program (ICDP) 5017-3-C borehole was cored in 2011 in a water depth of ~2.1 m, the lake level has dropped by almost 15 m, exposing some 320 m of a new, salt-encrusted shore. An FDEM survey was carried out on what is now land across the borehole. The results of the survey were compared to downhole gamma ray logging data. Three lithologies were found based on gamma-ray cutoff values, and they are in agreement with changes in apparent electric conductivity. The FDEM survey supplied additional spatial information on the subsurface geology, highlighting areas of fluid flow and fracturing, which were found to be aligned with the trend of small strike-slip faults and earthquake clusters from previous studies. The FDEM method is a reliable way of discerning shallow subsurface geology, even in harsh conditions where other geophysical methods are limited. © 2024 by the authors. Article 2024 10.3390/rs16111978 Remote Sensing 16 Multidisciplinary Digital Publishing Institute (MDPI) 11 Boreholes; C (programming language); Flow of fluids; Frequency domain analysis; Geophysics; Structural geology; Continental tectonics; Dead sea; Downhole methods; Extreme environment; Geophysical methods; Neotectonics; Saline environment; Shallow subsurface; Strike-slip and transform; Subsurface geology; Strike-slip faults https://www.scopus.com/inward/record.uri?eid=2-s2.0-85195995699&doi=10.3390%2frs16111978&partnerID=40&md5=5d917738dd88b8edce2287414c2af219 Cited by: 0; All Open Access, Gold Open Access Michael Lazar Linjing Cheng Uri Basson article RN96 2024 10.22498/pages.32.2.80 Past Global Changes Magazine 32 80-81 2 Rodrigo Martínez-Abarca Liseth Pérez Mark Brenner Frederik Schenk Jonathan Obrist-Farner Alex Correa-Metrio Thorsten Bauersachs Antje Schwalb article RN96 2024 10.22498/pages.32.2.82 Past Global Changes Magazine 32 82-83 2 L. Pérez-Cruz J. Urrutia-Fucugauchi article WOS:001194368500001 2024 10.1002/nsg.12293 NEAR SURFACE GEOPHYSICS 22 298-312 3 borehole; seismic array; tomography; traveltime Nikolaus Rein Marius P. Isken Dorina Domigall Matthias Ohrnberger Katrin Hannemann Frank Krueger Michael Korn Torsten Dahm article 2024 10.1038/s42003-024-07027-2 Commun Biol 7 1332 1 G. Westmeijer F. van Dam Riikka Kietäväinen C. Gonzalez-Rosales Stefan Bertilsson H. Drake Mark Dopson article sd-33-67-2024 2024 10.5194/sd-33-67-2024 Scientific Drilling 33 67--88 1 https://sd.copernicus.org/articles/33/67/2024/ C. Massiot L. Adam E. S. Boyd S. C. Cary D. R. Colman A. Cox E. Hughes G. Kilgour M. Lelli D. Liotta K. G. Lloyd T. Marr D. D. McNamara S. D. Milicich C. A. Miller S. Misra A. R. L. Nichols S. Pierdominici S. M. Rooyakkers D. R. Schmitt A. Stefánsson J. Stix M. B. Stott C. Thomas P. Villamor P. Wang S. J. Zarrouk participants article Heubeck2024129 The BASE (Barberton Archean Surface Environments) scientific drilling project aimed at recovering an unweathered continuous core from the Paleoarchean Moodies Group (ca. 3.2Ga), central Barberton Greenstone Belt (BGB), South Africa. These strata comprise some of the oldest well-preserved sedimentary strata on Earth, deposited within only a few million years in alluvial, fluvial, coastal-deltaic, tidal, and prodeltaic settings. They represent a very-high-resolution record of Paleoarchean surface conditions and processes. Moodies Group strata consist of polymict conglomerates, widespread quartzose, lithic and arkosic sandstones, siltstones, shales, and rare banded-iron formations (BIFs) and jaspilites, interbedded with tuffs and several thin lavas. This report describes objectives, drilling, and data sets; it supplements the operational report. Eight inclined boreholes between 280 and 495m length, drilled from November 2021 through July 2022, obtained a total of 2903m of curated core of variable quality through steeply to subvertically dipping, in part overturned stratigraphic sections. All drilling objectives were reached. Boreholes encountered a variety of conglomerates, diverse and abundant, mostly tuffaceous sandstones, rhythmically laminated shale-siltstone and banded-iron formations, and several horizons of early-diagenetic silicified sulfate concretions. Oxidative weathering reached far deeper than expected. Fracturing was more intense, and BIFs and jaspilites were thicker than anticipated. Two ca. 1km long mine adits and a water tunnel, traversing four thick stratigraphic sections within the upper Moodies Group in the central BGB, were also sampled. All boreholes were logged by downhole wireline geophysical instruments. The core was processed (oriented, slabbed, photographed, described, and archived) in a large, publicly accessible hall in downtown Barberton. A geological exhibition provided background explanations for visitors and related the drilling objectives to the recently established Barberton Makhonjwa Mountains World Heritage Site. A substantial education, outreach, and publicity program addressed the information needs of the local population and of local and regional stakeholders. © 2024 Christoph Heubeck et al. Article 2024 English 18168957 10.5194/sd-33-129-2024 Scientific Drilling 33 Copernicus Publications 129 – 172 2 Boreholes; Infill drilling; Iron; Shale; Stratigraphy; Sulfur compounds; Weathering; Archaean; Banded iron formations; Banded iron-formations; Banded-iron formations; Barberton; Greenstone belts; Paleoarchean; Scientific drilling; Siltstones; Surface environments; Sandstone https://www.scopus.com/inward/record.uri?eid=2-s2.0-85196639312&doi=10.5194%2fsd-33-129-2024&partnerID=40&md5=15015337e05e1c85ed9add006e99654e Cited by: 0; All Open Access, Gold Open Access Christoph Heubeck Nic Beukes Michiel De Kock Martin Homann Emmanuelle J. Javaux Takeshi Kakegawa Stefan Lalonde Paul Mason Phumelele Mashele Dora Paprika Chris Rippon Mike Tice Rodney Tucker Ryan Tucker Victor Ndazamo Astrid Christianson Cindy Kunkel article Yirenkyi2024 Article 2024 10.1038/s41598-024-62959-3 Scientific Reports 14 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85196481901&doi=10.1038%2fs41598-024-62959-3&partnerID=40&md5=0369e91c4999092a548b2360e503658d Cited by: 0; All Open Access, Gold Open Access Steven Yirenkyi Cyril D. Boateng Emmanuel Ahene Sylvester K. Danuor article Baxter2024 Branched glycerol monoalkyl glycerol tetraethers (brGMGTs), a relatively understudied group of bacterial membrane lipids structurally similar to branched glycerol dialkyl glycerol tetraethers (brGDGTs), appear to be strongly influenced by temperature in terrestrial settings. In surficial bottom sediments of East African lakes, the abundance of brGMGTs relative to the sum of brGMGTs and brGDGTs (%brGMGT) and brGMGT distribution are strongly related to local mean annual air temperature (MAAT), stimulating development of new paleothermometers. However, applications of these methods to lake-sediment records are currently lacking. Here we investigate brGMGT concentrations and distributions in 916 samples throughout the 250,000-year (250-kyr) sediment sequence from Lake Chala, a presently fresh and permanently stratified (meromictic) tropical crater lake. All seven previously identified brGMGTs occur abundantly, reflected in a relatively high average %brGMGT of 19%. BrGMGTs and brGDGTs concentrations throughout the sequence are strongly correlated (R = 0.83, p < 0.001), suggesting that their producers and/or associated ecological niches substantially overlap. Clear distinction can be made between brGMGTs produced predominantly in the bottom sediments (H1034a and H1034c) versus the anoxic lower water column (H1020a-c and H1034b). Although a 17-month monitoring study of Lake Chala suggested brGMGTs are primarily produced in the sediments, down-core data assign greater importance to aquatic production than previously estimated. Instead of reflecting temperature, %brGMGT variations showed greatest similarity to GDGT proxies reflecting lake depth and/or mixing regime. BrGMGT-based temperature models produce ambiguous reconstructions, showing little similarity to known global temperature trends or the brGDGT-based mean summer temperature (MST) reconstruction from the same sediments. © 2024 The Authors Article 2024 10.1016/j.orggeochem.2024.104812 Organic Geochemistry 195 Elsevier Ltd East Africa; Glycerol; Lipids; Surficial sediments; Branched glycerol dialkyl glycerol tetraether; Branched glycerol monoalkyl glycerol tetraether; DeepCHALLA; East Africa; H-shaped; H-shaped GDGT; ICDP; Lake chala; Lake sediments; Paleoclimates; Tetraethers; air temperature; crater lake; lipid; paleoclimate; relative abundance; sediment transport; water column; Lakes https://www.scopus.com/inward/record.uri?eid=2-s2.0-85199247952&doi=10.1016%2fj.orggeochem.2024.104812&partnerID=40&md5=423a1277759f8f5e3b327d9ec44cbffb Cited by: 0; All Open Access, Hybrid Gold Open Access A.J. Baxter F. Peterse D. Verschuren J.S. Sinninghe Damsté article Reinhardt2024 Microbial life on Earth was well established in the Paleoarchean, but insight into early ecosystem diversity and thus, the complexity of the early biological carbon cycle is limited. Here we investigated four carbonaceous chert samples from the lower platform facies of the ca. 3.42-billion-year-old Buck Reef Chert, Barberton greenstone belt. The analysis on multiple scales revealed exceptionally well-preserved carbonaceous matter, even on molecular level (aliphatic and aromatic hydrocarbons), resulting from rapid silicification. Geochemical evidence from stable carbon and multiple sulfur isotopes supports the presence of different microbial metabolisms in the Paleoarchean ecosystem. The local biological carbon cycle was dominated by photoautotrophs, but autotrophic sulfate reducers and methane- or acetate-producing microbes were also present. In areas of microbial methane or acetate release, methanotrophs or acetotrophs contributed to the overall biomass. These results highlight the metabolic diversity in the lower platform environment of the Buck Reef Chert, and underline that an advanced biological carbon cycle already existed in the early Archean. © 2024 The Authors Article 2024 10.1016/j.precamres.2024.107289 Precambrian Research 402 Elsevier B.V. Archean; carbon cycle; chert; geochemistry; greenstone belt; marine ecosystem; metabolism; paleoecology; species diversity https://www.scopus.com/inward/record.uri?eid=2-s2.0-85182576861&doi=10.1016%2fj.precamres.2024.107289&partnerID=40&md5=a98f04b076257aec9987de00a4345ece Cited by: 9; All Open Access, Green Open Access, Hybrid Gold Open Access M. Reinhardt V. Thiel J.-P. Duda A. Hofmann D. Bajnai W. Goetz A. Pack J. Reitner M. Schanofski J. Schönig M.J. Whitehouse H. Drake article Vinnepand2024 Situated within a 1.07 million-year-old meteorite crater, Lake Bosumtwi in Ghana stands as a pivotal location for comprehending climatic, ecological and environmental fluctuations within the sub-Saharan region of West Africa. The region's susceptibility to seasonal environmental shifts and climate oscillations is heightened by the annual movements of the tropical rain belt driven by atmospheric circulation. Yet, there is no satisfying age-depth model available for the entire sedimentary sequence strongly limiting our understanding of changes in this circulation pattern and associated (broad-scale) environmental responses during the last million years in the local to regional context of Lake Bosumtwi. To overcome this, we statistically examine the cyclicity in total natural gamma ray (NGR) data on a core from the lake's centre and create a cyclostratigraphic age-depth model. The calculated maximum age of 946 ka agrees well with the meteorite impact age (∼10 % offset). In order to refine this purely statistical approach, we also perform a correlative age-depth model using 33 tie points accounting for the complexity of climatic and environmental imprints to the NGR record that may exceed direct insolation related effects. Special attention is paid to the core's robustly dated (14C, OSL, U/Th) uppermost part covering the last 200 ka. Here, high NGR and co-varying K counts coincide with warm periods (except of the water-saturated and unconsolidated Holocene part) and the inverse for glacials and stadials. Based on this, we define tie points for correlating our NGR data to the age-depth model of a NE Atlantic SST record. Comparing our results to the correlation target, other global climate records and Sahara dust flux data reveals striking similarities and supports a proxy understanding with increased in wash of K-enriched terrigenous material from the crater rims in warm and moist periods (high NGR) and K-depleted dust input in stadials possibly contributing to low NGR values in addition to reduced input of K-enriched sediments from the crater rims. Our correlative age model results in precession amplitudes matching eccentricity well, providing further support especially because an over-tuning is unlikely with the used 33 tie points. Overall we provide crucial chronological context to numerous datasets along with environmental constrains that can be used to study the potential habitat availability of early anatomically modern humans in West Africa. © 2023 Article 2024 10.1016/j.quascirev.2023.108478 Quaternary Science Reviews 325 Ashanti; Ghana; Lake Bosumtwi; Sahara; Climate change; Climate models; Dust; Gamma rays; Meteorites; Rain; Sediments; Tropics; Climate dynamics; Depth models; Environmental change; ICDP; Lake bosumtwi; Natural gamma ray; Quaternary; Tie points; West Africa; Western africa; atmospheric circulation; climate variation; crater; environmental change; gamma radiation; potash; Quaternary; sedimentary sequence; Lakes https://www.scopus.com/inward/record.uri?eid=2-s2.0-85181056438&doi=10.1016%2fj.quascirev.2023.108478&partnerID=40&md5=40f1b179c6315358518740ce5462b8fe Cited by: 1 Mathias Vinnepand Christian Zeeden Thomas Wonik William Gosling Anders Noren Jochem Kück Simona Pierdominici Silke Voigt Mehrdad Sardar Abadi Arne Ulfers Sylvester Danour Kweku Afrifa Stefanie Kaboth-Bahr article Trauth2024 The directly dated RRMarch2021 age model (Roberts et al., 2021) for the ∼293 m long composite core from Chew Bahir, southern Ethiopia, has provided a valuable chronology for long-term climate changes in northeastern Africa. However, the age model has limitations on shorter time scales (less than 1–2 precession cycles), especially in the time range <20 kyr BP (kiloyears before present or thousand years before 1950) and between ∼155 and 428 kyr BP. To address those constraints we developed a partially orbitally tuned age model. A comparison with the ODP Site 967 record of the wetness index from the eastern Mediterranean, 3300 km away but connected to the Ethiopian plateau via the River Nile, suggests that the partially orbitally tuned age model offers some advantages compared to the exclusively directly dated age model, with the limitation of the reduced significance of (cross) spectral analysis results of tuned age models in cause-effect studies. The availability of this more detailed age model is a prerequisite for further detailed spatiotemporal correlations of climate variability and its potential impact on the exchange of different populations of Homo sapiens in the region. © 2024 The Authors Article 2024 10.1016/j.qsa.2024.100208 Quaternary Science Advances 15 Elsevier Ltd https://www.scopus.com/inward/record.uri?eid=2-s2.0-85197024154&doi=10.1016%2fj.qsa.2024.100208&partnerID=40&md5=94d0360430dd64038edb7385859abd3a Cited by: 0; All Open Access, Hybrid Gold Open Access Martin H. Trauth Asfawossen Asrat Markus L. Fischer Verena Foerster Stefanie Kaboth-Bahr Henry F. Lamb Norbert Marwan Helen M. Roberts Frank Schaebitz article Qin2024168 Article 2024 10.11928/j.issn.1001-7410.2024.05.08 Quaternary Sciences 44 1188-1204 5 L. Yang Y. Gao Z. Wu Q. Zhang article Greenwood2024219 Drilling target locations of the International Continental Scientific Drilling Program (ICDP) project Drilling the Ivrea-Verbano zonE (DIVE) have been initially proposed based on geological knowledge of surface outcrops and the structural context of the Ivrea-Verbano zone (IVZ) and of the Insubric Line. For the determination of the exact locations of drilling sites as well as for drilling geometry planning, we have carried out a series of active seismic experiments to image the subsurface at high resolution. The two drilling sites of project DIVE in Ossola Valley, one near Ornavasso and the other in Megolo di Mezzo, in the central part of the Ivrea-Verbano zone have been surveyed with site-specific velocity models and a seismic data processing chain. The findings have been interpreted in relation with the outcropping structures. These suggest a reasonable continuity from the surface. They also guide the planned borehole orientations: near-vertical at DT-1B (Ornavasso) into the tightly folded Massone Antiform and at 15-20° from the vertical in Megolo across a flank of the broad Proman Anticline. The seismic surveys indicate that the sedimentary overburden is up to 50 m deep at the specific drill sites and can be minimized by relocating the proposed locations. The seismic surveys also indicate that the center of the Ossola Valley contains about 550 m of sedimentary infill, defining the interface of bedrock and Quaternary glacial sediments at about 300 m below sea level. © 2024 Andrew Greenwood et al. Article 2024 10.5194/sd-33-219-2024 Scientific Drilling 33 Copernicus Publications 219 – 236 2 Geological surveys; Glacial geology; Glaciers; Hydrogeology; Jurassic; Miocene; Seismic prospecting; Seismic response; Structural geology; Active seismic; Continental scientific drillings; Drilling projects; Drilling targets; High resolution; Phase I; Seismic surveys; Site-specific; Target characterization; Target location; Sedimentology https://www.scopus.com/inward/record.uri?eid=2-s2.0-85203127304&doi=10.5194%2fsd-33-219-2024&partnerID=40&md5=7299119018368c96f1d5e0874521b098 Cited by: 0; All Open Access, Gold Open Access Andrew Greenwood György Hetényi Ludovic Baron Alberto Zanetti Othmar Müntener Nicolò Barago Davide Berno Florian Bleibinhaus Mattia Bonazzi Lorenzo Candioti Steve Henchoz Gerado Maurizio Valentin Métraux Alexis Neven Gerald Raymond Alberto Roselli Matteo Scarponi Edith Sotelo Thomas Tsaner article Lavallée2024412 Article 2024 10.1017/S1062798724000292 European Review 32 412 – 434 4 https://www.scopus.com/inward/record.uri?eid=2-s2.0-105001086928&doi=10.1017%2fS1062798724000292&partnerID=40&md5=2ac281f3a8bb1594fc283a7802538f5e Cited by: 0; All Open Access, Hybrid Gold Open Access Yan Lavallee Jackie E. Kendrick John C. Eichelberger Paolo Papale Freysteinn Sigmundsson Donald B. Dingwell article Ogasawara2024817 Article 2024 10.2320/matertrans.MT-Z2024004 Materials Transactions 65 817 – 823 7 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85197348178&doi=10.2320%2fmatertrans.MT-Z2024004&partnerID=40&md5=e3d474d90888c376a38c81426fb3c385 Cited by: 0; All Open Access, Gold Open Access Hiroshi Ogasawara Yoshihiro Mima Akimasa Ishida Siyanda Mngadi Mitsuya Higashi Yasuo Yabe Akio Funato Takatoshi Ito Masao Nakatani Raymond Durrheim article Jin2024Q1 Article 2024 10.1190/geo2023-0340.1 Geophysics 89 Q1 – Q12 4 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85195423626&doi=10.1190%2fgeo2023-0340.1&partnerID=40&md5=992f0d28789ceead862c8a5b9a69d1d9 Cited by: 1 Zhong-Yuan Jin Zhan-Wu Lu Wei Fu He-Sheng Hou article RN71 Studying past ecosystems from ancient environmental DNA preserved in lake sediments (sedaDNA) is a rapidly expanding field. This research has mainly involved Holocene sediments from lakes in cool climates, with little known about the suitability of sedaDNA to reconstruct substantially older ecosystems in the warm tropics. Here, we report the successful recovery of chloroplast trnL (UAA) sequences (trnL-P6 loop) from the sedimentary record of Lake Towuti (Sulawesi, Indonesia) to elucidate changes in regional tropical vegetation assemblages during the lake's Late Quaternary paleodepositional history. After the stringent removal of contaminants and sequence artifacts, taxonomic assignment of the remaining genuine trnL-P6 reads showed that native nitrogen-fixing legumes, C3 grasses, and shallow wetland vegetation (Alocasia) were most strongly associated with >1-million-year-old (>1 Ma) peats and silts (114–98.8 m composite depth; mcd), which were deposited in a landscape of active river channels, shallow lakes, and peat-swamps. A statistically significant shift toward partly submerged shoreline vegetation that was likely rooted in anoxic muddy soils (i.e., peatland forest trees and wetland C3 grasses (Oryzaceae) and nutrient-demanding aquatic herbs (presumably Oenanthe javanica)) occurred at 76 mcd (~0.8 Ma), ~0.2 Ma after the transition into a permanent lake. This wetland vegetation was most strongly associated with diatom ooze (46–37 mcd), thought to be deposited during maximum nutrient availability and primary productivity. Herbs (Brassicaceae), trees/shrubs (Fabaceae and Theaceae), and C3 grasses correlated with inorganic parameters, indicating increased drainage of ultramafic sediments and laterite soils from the lakes' catchment, particularly at times of inferred drying. Downcore variability in trnL-P6 from tropical forest trees (Toona), shady ground cover herbs (Zingiberaceae), and tree orchids (Luisia) most strongly correlated with sediments of a predominantly felsic signature considered to be originating from the catchment of the Loeha River draining into Lake Towuti during wetter climate conditions. However, the co-correlation with dry climate-adapted trees (i.e., Castanopsis or Lithocarpus) plus C4 grasses suggests that increased precipitation seasonality also contributed to the increased drainage of felsic Loeha River sediments. This multiproxy approach shows that despite elevated in situ temperatures, tropical lake sediments potentially comprise long-term archives of ancient environmental DNA for reconstructing ecosystems, which warrants further exploration. © 2024 The Authors. Geobiology published by John Wiley & Sons Ltd. Article 2024 10.1111/gbi.12599 Geobiology 22 John Wiley and Sons Inc e12599 3 Greater Sunda Islands; Indonesia; Lake Towuti; Malili Lakes; South Sulawesi; Sulawesi; Sulawesi; Sunda Isles; catchment; ground cover; Holocene; landscape ecology; nutrient availability; ooze; paleoecology; paleoenvironment; peatland; seasonality; tropical forest https://www.ncbi.nlm.nih.gov/pubmed/38745401 Cited by: 0; All Open Access, Hybrid Gold Open Access M. A. Ekram M. Campbell S. H. Kose C. Plet R. Hamilton S. Bijaksana K. Grice J. Russell J. Stevenson H. Vogel M. J. L. Coolen article Parisi2024 Article 2024 10.1016/j.palaeo.2024.112483 Palaeogeography, Palaeoclimatology, Palaeoecology 655 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85203411862&doi=10.1016%2fj.palaeo.2024.112483&partnerID=40&md5=94cd534929b784cf363580b29a4da45b Cited by: 1; All Open Access, Hybrid Gold Open Access R. Parisi T.M. Cronin G. Aiello D. Barra D.L. Danielopol D.J. Horne I. Mazzini article DiChiara2024 Article 2024 10.1029/2023GC011092 Geochemistry, Geophysics, Geosystems 25 3 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85186867348&doi=10.1029%2f2023GC011092&partnerID=40&md5=5bac85ec99c54f68fcbaad10376cabeb Cited by: 1; All Open Access, Gold Open Access, Green Open Access A. Di Chiara M.W. Hounslow B.A. Maher V. Karloukovski M. Van Daele M. Blaauw D. Verschuren article Beraus2024237 Article 2024 10.5194/sd-33-237-2024 Scientific Drilling 33 237 – 248 2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85206495700&doi=10.5194%2fsd-33-237-2024&partnerID=40&md5=1b6f9240b1b2bafa9e1a50b90df32fc8 Cited by: 0 Sarah Beraus Thomas Burschil Hermann Buness Daniel Köhn Thomas Bohlen Gerald Gabriel article RN96 2024 10.22498/pages.32.2.118 Past Global Changes Magazine 32 118-119 2 T. H. Donders D. Oliviera M.-F. Sánchez Goñi Laura Sadori article Kearney2024 Article 2024 10.1038/s41598-024-59639-7 Scientific Reports 14 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85194900143&doi=10.1038%2fs41598-024-59639-7&partnerID=40&md5=54b0214098801fcfcc1a21a3e355e819 Cited by: 0; All Open Access, Gold Open Access Rebecca J. Kearney Markus J. Schwab Daniel Redant Ina Neugebauer Oona Appelt Cécile Blanchet Jan Fietzke Christina Günter Daniela J. M. Müller Rik Tjallingii Achim Brauer article Martell2024 With several upcoming sample return missions, such as the Mars Sample Return Campaign, non-destructive methods will be key to maximizing their scientific output. In this study, we demonstrate that the combination of neutron and X-ray tomography provides an important tool for the characterization of such valuable samples. These methods allow quantitative analyses of internal sample features and also provide a guide for further destructive analyses with little to no sample treatment, which maintains sample integrity, including minimizing the risk of potential contamination. Here, we present and review the results from four case studies of terrestrial impactites and meteorites along with their analytical setup. Using combined X-ray and neutron tomography, a Ni-Fe silicide spherule, that is, projectile material, was located within a Libyan Desert Glass sample and the distribution of hydrous phases was pinpointed in selected impactite samples from the Chicxulub IODP-ICDP Expedition 364 drill core and the Luizi impact structure, as well as in the Miller Range 03346 Martian meteorite. © 2024. The Authors. Review 2024 10.1029/2023JE008222 Journal of Geophysical Research: Planets 129 John Wiley and Sons Inc 2 impact structure; iron; Mars; meteorite; nickel; spherule; X-ray tomography https://www.scopus.com/inward/record.uri?eid=2-s2.0-85184929812&doi=10.1029%2f2023JE008222&partnerID=40&md5=5c306321fd38f66de738d4e447de63f2 Cited by: 1; All Open Access, Hybrid Gold Open Access J. Martell C. Alwmark R. Woracek S. Alwmark S. Hall L. Ferrière L. Daly C. Bender Koch J. Hektor S. Johansson L. Helfen A. Tengattini D. Mannes article sd-33-173-2024 2024 10.5194/sd-33-173-2024 Scientific Drilling 33 173--190 2 https://sd.copernicus.org/articles/33/173/2024/ L. Chiaraluce R. Bennett D. Mencin W. Johnson M. R. Barchi M. Bohnhoff P. Baccheschi A. Caracausi C. Calamita A. Cavaliere A. Gualandi E. Mandler M. T. Mariucci L. Martelli S. Marzorati P. Montone D. Pantaleo S. Pucci E. Serpelloni M. Supino S. Stramondo C. Hanagan L. Van Boskirk M. Gottlieb G. Mattioli M. Urbani F. Mirabella A. Akimbekova S. Pierdominici T. Wiersberg C. Marone L. Palmieri L. Schenato article Westmeijer2024591 Scientific drilling expeditions offer a unique opportunity to characterize microbial communities in the subsurface that have long been isolated from the surface. With subsurface microbial biomass being low in general, biological contamination from the drilling fluid, sample processing, or molecular work is a major concern. To address this, characterization of the contaminant populations in the drilling fluid and negative extraction controls are essential for assessing and evaluating such sequencing data. Here, rock cores down to 2250m depth, groundwater-bearing fractures, and the drilling fluid were sampled for DNA to characterize the microbial communities using a broad genomic approach. However, even after removing potential contaminant populations present in the drilling fluid, notorious contaminants were abundant and mainly affiliated with the bacterial order Burkholderiales. These contaminant microorganisms likely originated from the reagents used for isolating DNA despite stringent quality standards during the molecular work. The detection of strictly anaerobic sulfate reducers such as Candidatus Desulforudis audaxviator suggested the presence of autochthonous deep biosphere taxa in the sequenced libraries, yet these clades represented only a minor fraction of the sequence counts (<0.1 %), hindering further ecological interpretations. The described methods and findings emphasize the importance of sequencing extraction controls and can support experimental design for future microbiological studies in conjunction with continental drilling operations. © 2024 George Westmeijer et al. Article 2024 10.5194/bg-21-591-2024 Biogeosciences 21 Copernicus Publications 591 – 604 2 Sweden; bacterium; bedrock; biomass; biosphere; DNA; drilling fluid; microbiology https://www.scopus.com/inward/record.uri?eid=2-s2.0-85184077946&doi=10.5194%2fbg-21-591-2024&partnerID=40&md5=2ca1bd5a9879232b51f567b9c4472a9e Cited by: 0 George Westmeijer Cristina Escudero Claudia Bergin Stephanie Turner Magnus Ståhle Maliheh Mehrshad Prune Leroy Moritz Buck Pilar López-Hernández Jens Kallmeyer Ricardo Amils Stefan Bertilsson Mark Dopson article RN96 2024 10.22498/pages.32.2.122 Past Global Changes Magazine 32 122-123 2 A. Endeshaw Anneleen Foubert H. Negga Balemwal Atnafu V. Rime Derek Keir Tesfaye Kidane ADD-On Team article Owen2024 The South Kenya Rift is comprised of a series of N-S-oriented grabens with sediments that preserve an approximate one-million-year environmental history that reflects the interplay of climate, tectonism and volcanism. This study attempts to disentangle the relative roles of these major controls by comparing the geochemical records preserved in three sedimentary basins. The study focuses on the Koora Basin using bulk geochemical data in a 139-m-long core. This record is then compared with geochemical data and environmental histories from a 196-m-long core at Magadi and outcrops in the Olorgesailie Basin. Four climatic phases (1000–850; 850–470; 470–400; 400–0 ka) are recognised at Koora, which can also be distinguished in the Magadi and Olorgesailie Basins. However, inter-basin contrasts also suggest that additional, non-climatic factors influenced these geochemical histories, particularly during four intervals. These include 1) the Magadi Transition (MT; ∼770–700 ka), 2) the Magadi Tectonic Event (MTE; ∼540 ka), 3) the Koora Instability Period (KIP; ∼325–180 ka), and 4) the Trona Precipitation Period (TPP; ∼105–0 ka). Prior to the MT, Zr/TiO2, La/Lu, Mo, As, V and Na/Ca in Magadi and Koora cores were similar but afterwards diverged. Major reductions in transition metals at Magadi during the MTE reflect tectonically-induced cross-rift drainage diversion. This contrasts with the Koora and Olorgesailie basins where these metals were constant from ∼1000 to 300 ka. The KIP represents a significant increase in volcanic inputs to the Koora Basin and increased geochemical variability. Bromine (Br), which reflects peralkaline volcanic activity and/or evaporative concentration, is elevated during the KIP at Koora but is below detection limits in the rest of the Koora core. Br in the Magadi core does not correlate with that in the Koora record, suggesting contrasting accumulation processes. The TPP represents a phase of trona precipitation at Magadi but not at Koora. This difference partly reflects increased magmatic CO2 rising along faults in the Magadi basin during a period of increasing aridity. Rare-earth element patterns indicate a major change at Magadi with many anomalies after about 325 ka to the present, caused by the development of hypersaline waters, which did not occur at Koora or Olorgesailie. The geochemical data from the three basins help to partially separate climatic controls from those related to volcanism, tectonism and local geomorphology. © 2023 Article 2024 10.1016/j.palaeo.2023.111986 Palaeogeography, Palaeoclimatology, Palaeoecology 637 Elsevier B.V. East African Rift; Kenya; Kenya Rift; environmental history; geochemistry; mineralogy; paleolimnology; Quaternary; volcanism; volcanology https://www.scopus.com/inward/record.uri?eid=2-s2.0-85181115776&doi=10.1016%2fj.palaeo.2023.111986&partnerID=40&md5=ffddec60e6a74cadaacc58fea70b1f09 Cited by: 1 R. Bernhart Owen Nathan Rabideaux Jordon Bright Carolina Rosca Robin W. Renaut Richard Potts Anna K. Behrensmeyer Alan L. Deino Andrew S. Cohen Veronica Muiruri René Dommain article sd-33-21-2024 2024 10.5194/sd-33-21-2024 Scientific Drilling 33 21--31 1 https://sd.copernicus.org/articles/33/21/2024/ M. A. Berke D. J. Peppe Team article sd-33-93-2024 2024 10.5194/sd-33-93-2024 Scientific Drilling 33 93--108 2 https://sd.copernicus.org/articles/33/93/2024/ C. C. Beck M. Berke C. S. Feibel V. Foerster L. Olaka H. M. Roberts C. A. Scholz K. Cantner A. Noren G. M. Kiptoo J. Muirhead the Deep Drilling in the Turkana Basin (DDTB) project team article RN96 2024 10.22498/pages.32.2.106 Past Global Changes Magazine 32 106-107 2 Christoph Heubeck Nic Beukes article Kaskes2024 Article 2024 10.1093/pnasnexus/pgad414 PNAS Nexus 3 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85182567708&doi=10.1093%2fpnasnexus%2fpgad414&partnerID=40&md5=1da0b1f6695b6952198db5e78492bdfe Cited by: 0; All Open Access, Gold Open Access Pim Kaskes Marta Marchegiano Marion Peral Steven Goderis Philippe Claeys article Shervais2024 Article 2024 10.1016/j.geothermics.2023.102865 Geothermics 117 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85177873679&doi=10.1016%2fj.geothermics.2023.102865&partnerID=40&md5=a2d359cf012aadc5a477ef1d831e88da Cited by: 8; All Open Access, Gold Open Access, Green Open Access John W. Shervais Jacob DeAngelo Jonathan M. Glen Dennis L. Nielson Sabodh Garg Patrick Dobson Erika Gasperikova Eric Sonnenthal Lee M. Liberty Dennis L. Newell Drew Siler James P. Evans article Peng2024 Review 2024 10.1016/j.earscirev.2024.104735 Earth-Science Reviews 252 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85188517238&doi=10.1016%2fj.earscirev.2024.104735&partnerID=40&md5=1fc93f35cf46bdd7282915d0260aa2be Cited by: 2 Cheng Peng Changchun Zou Shuxia Zhang Jiangbo Shu Chengshan Wang article Montone20241385 Article 2024 10.5194/se-15-1385-2024 Solid Earth 15 1385 – 1406 11 https://www.scopus.com/inward/record.uri?eid=2-s2.0-105002704580&doi=10.5194%2fse-15-1385-2024&partnerID=40&md5=c99e900fd209793e9f526bd56bbc2a72 Cited by: 0; All Open Access, Gold Open Access Paola Montone Simona Pierdominici M. Teresa Mariucci Francesco Mirabella Marco Urbani Assel Akimbekova Lauro Chiaraluce Wade Johnson Massimiliano Rinaldo Barchi article Han2024741 Article 2024 10.1016/j.petsci.2023.10.031 Petroleum Science 21 741 – 751 2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85187412189&doi=10.1016%2fj.petsci.2023.10.031&partnerID=40&md5=56c619057039f5e75efb9e6c54e24cad Cited by: 3; All Open Access, Gold Open Access Shuang-Biao Han Chao-Han Xiang Xin Du Lin-Feng Xie Jie Huang Cheng-Shan Wang article RN96 2024 10.22498/pages.32.2.72 Past Global Changes Magazine 32 72-73 2 A. C. Gebhardt J. Brigham-Grette I. Castaneda M. Melles P. Minyuk V Wennrich article Ninard202425 Article 2024 10.7306/VJ.22.3 Volumina Jurassica 22 25 – 34 https://www.scopus.com/inward/record.uri?eid=2-s2.0-105004006293&doi=10.7306%2fVJ.22.3&partnerID=40&md5=d6a0057ce7737f0443666216b390caf5 Cited by: 0; All Open Access, Green Open Access Krzysztof Ninard Alfred Uchman Grzegorz Pieńkowski Stephen P. Hesselbo article DeAngelo2024 Article 2024 10.1016/j.geothermics.2023.102882 Geothermics 117 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85178654658&doi=10.1016%2fj.geothermics.2023.102882&partnerID=40&md5=03ed63a75ae826765523ef55c0c2a1e1 Cited by: 5; All Open Access, Green Open Access, Hybrid Gold Open Access Jacob DeAngelo John W. Shervais Jonathan M. Glen Dennis Nielson Sabodh Garg Patrick F. Dobson Erika Gasperikova Eric Sonnenthal Lee M. Liberty Drew L. Siler James P. Evans article Menegoni20243961 Article 2024 10.1016/j.jrmge.2024.03.012 Journal of Rock Mechanics and Geotechnical Engineering 16 3961 – 3981 10 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85198113673&doi=10.1016%2fj.jrmge.2024.03.012&partnerID=40&md5=e86b25f1770d8a8f5f647b146dcb9ff9 Cited by: 3; All Open Access, Gold Open Access Niccolò Menegoni Yuri Panara Andrew Greenwood Davide Mariani Alberto Zanetti György Hetényi article RN96 2024 10.22498/pages.32.2.126 Past Global Changes Magazine 32 126-127 2 Christian Koeberl article Suzuki2024 The deep mafic magmatic staging chambers of layered mafic intrusions have been conjectured but not imaged. Their existence has long been postulated from geochemical models which require multiple magma injections from staging chambers to account for their multi-scale igneous layering and variations in sources and degrees of crustal contamination. For the Bushveld Complex of southern Africa, the world's largest layered mafic intrusion, seismic receiver functions identify a diffuse crust-mantle transition beneath the Complex that suggests high velocity lower crust and/or uppermost lithospheric mantle. Here we present 3D gravity modelling of the Bushveld Complex that includes dense material at the crust-mantle boundary, imaging for the first time, remnants of magma staging chambers. They underlie the whole Bushveld Complex and extend westwards to the Molopo Farms Complex in Botswana. Feeders to the Bushveld Complex coincide with intersections of major faults like the Thabazimbi-Murchison Lineament and Sugarbush Fault with the staging chamber. This identification of magmatic staging chambers beneath the Bushveld relates to similar geophysically imaged lower crustal features beneath the Duluth and Stillwater Complexes. Comparison of seismic and gravity data with geochemical models from other complexes aid in development of models for the magmatic architecture of layered mafic intrusions in general. © 2024 Elsevier B.V. Article 2024 10.1007/s00248-024-02434-8 Microbial Ecology 87 https://link.springer.com/article/10.1007/s00248-024-02434-8?utm_source=rct_congratemailt&utm_medium=email&utm_campaign=oa_20241002&utm_content=10.1007/s00248-024-02434-8 Cited by: 2 Yohey Suzuki Susan J. Webb Mariko Kouduka Hanae Kobayashi Julio Castillo Jens Kallmeyer Kgabo Moganedi Amy J. Allwright Reiner Klemd Frederick Roelofse Mabatho Mapiloko Stuart J. Hill Robert B. Ashwal article item_5026155 All datasets provided in the operational dataset (Heubeck et al., 2024) of the ICDP project BASE (ICDP 5069) consist of metadata, data and/or images. Here, a summary of explanations of the tables, data and images exported from the database of the project (mDIS BASE) are given and are complimented by additional information on data from measurements done in the laboratory prior to the sampling party. Finally, the sampling data from the first two sam-pling parties are added. Some basic definitions of identifiers used in ICDP, depths corrections and measurements are also introduced. Article 2024 eng 10.48440/ICDP.5069.002 International Continental Scientific Drilling Program, GFZ German Research Centre for Geosciences International Continental Scientific Drilling Program, GFZ German Research Centre for Geosciences GFZ data services

Potsdam

30 C. Heubeck N. Beukes M. Kock M. Homann E. J. Javaux T. Kakegawa S. Lalonde P. Mason M. Tice P. Mashele D. Paprika C. Rippon Rodney Tucker Ryan Tucker V. Ndazamo A. Christianson Cindy Kunkel article Quraish2024 In 2016, IODP-ICDP Expedition 364 recovered an 829-meter-long core within the peak ring of the Chicxulub impact crater (Yucatán, Mexico), allowing us to investigate the post-impact recovery of the heat-sterilized deep continental microbial biosphere at the impact site. We recently reported increased cell biomass in the impact suevite, which was deposited within the first few hours of the Cenozoic, and that the overall microbial communities differed significantly between the suevite and the other main core lithologies (i.e., the granitic basement and the overlying Early Eocene marine sediments; Cockell et al., 2021). However, only seven rock intervals were previously analyzed from the geologically heterogenic and impact-deformed 587-m-long granitic core section below the suevite interval. Here, we used 16S rRNA gene profiling to study the microbial community composition in 45 intervals including (a) 31 impact-shocked granites, (b) 7 non-granitic rocks (i.e., consisting of suevite and impact melt rocks intercalated into the granites during crater formation and strongly serpentinized pre-impact sub-volcanic, ultramafic basanite/dolerite), and (c) 7 cross-cut mineral veins of anhydride and silica. Most recovered microbial taxa resemble those found in hydrothermal systems. Spearman correlation analysis confirmed that the borehole temperature, which gradually increased from 47 to 69°C with core depth, significantly shaped a subset of the vertically stratified modern microbial community composition in the granitic basement rocks. However, bacterial communities differed significantly between the impoverished shattered granites and nutrient-enriched non-granite rocks, even though both lithologies were at similar depths and temperatures. Furthermore, Spearman analysis revealed a strong correlation between the microbial communities and bioavailable chemical compounds and suggests the presence of chemolithoautotrophs, which most likely still play an active role in metal and sulfur cycling. These results indicate that post-impact microbial niche separation has also occurred in the granitic basement lithologies, as previously shown for the newly formed lithologies. Moreover, our data suggest that the impact-induced geochemical boundaries continue to shape the modern-day deep biosphere in the granitic basement underlying the Chicxulub crater. © 2023 The Authors. Geobiology published by John Wiley & Sons Ltd. Article 2024 10.1111/gbi.12583 Geobiology 22 John Wiley and Sons Inc 1 Bacteria; Microbiota; RNA, Ribosomal, 16S; Silicon Dioxide; Mexico [North America]; Yucatan; acid anhydride; chemical compound; mineral; RNA 16S; silicon dioxide; sulfur; basement rock; bioavailability; borehole; cell; crater; granitoid; hydrothermal system; marine sediment; microbial activity; microbial community; separation; sulfur cycle; article; bioavailability; biogeochemical cycling; biomass; biosphere; chemolithoautotroph; correlation analysis; granite; Mexico; microbial community; nonhuman; Paleozoic; rock; sediment; temperature; Ypresian https://www.scopus.com/inward/record.uri?eid=2-s2.0-85181216283&doi=10.1111%2fgbi.12583&partnerID=40&md5=d3c2e59f7ea05b2995eb1152a00a3ee5 Cited by: 0; All Open Access, Hybrid Gold Open Access Sohaib Naseer Quraish Charles Cockell Cornelia Wuchter David Kring Kliti Grice Marco J. L. Coolen article mashele2024 2024 10.3389/frym.2024.1252881 Frontiers for Young Minds 12 P Mashele C Heubeck article Baxter20242877 High-resolution paleoclimate records from tropical continental settings are greatly needed to advance understanding of global climate dynamics. The International Continental Scientific Drilling Program (ICDP) project DeepCHALLA recovered a 214.8 m long sediment sequence from Lake Chala, a deep and permanently stratified (meromictic) crater lake in eastern equatorial Africa, covering the past ca. 250 000 years (250 kyr) of continuous lacustrine deposition since the earliest phase of lake-basin development. Lipid biomarker analyses on the sediments of Lake Chala can provide quantitative records of past variation in temperature and moisture balance from this poorly documented region. However, the degree to which climate proxies derived from aquatically produced biomarkers are affected by aspects of lake developmental history is rarely considered, even though it may critically influence their ability to consistently register a particular climate variable through time. Modern-system studies of Lake Chala revealed crucial information about the mechanisms underpinning relationships between proxies based on isoprenoid (iso-) and branched (br-) glycerol dialkyl glycerol tetraethers (GDGTs) and the targeted climate variables, but the persistence of these relationships in the past remains unclear. Here we assess the reliability of long-term climate signals registered in the sediments of Lake Chala by comparing downcore variations in GDGT distributions with major phases in lake-system evolution as reflected by independent proxies of lake depth, mixing regime and nutrient dynamics: seismic reflection data, lithology and fossil diatom assemblages. Together, these records suggest that during early lake history (before ca. 180-200 ka) the distinct mixing-related depth zones with which specific GDGT producers are associated in the modern-day lake were not yet formed, likely due to more open lake hydrology and absence of chemical water-column stratification. Consequently absolute GDGT concentrations dating to this period are relatively low, proxies sensitive to water-column stratification (e.g., branched versus isoprenoid tetraether (BIT) index) display highly irregular temporal variability, and correlations between proxies are dissimilar to expectations based on modern-system understanding. A sequence of lake-system changes between ca. 180-200 and ca. 80 ka first established and then strengthened the chemical density gradient, promoting meromictic conditions despite the overall decrease in lake depth due to the basin gradually being filled up with sediments. From ca. 180 ka onward some GDGTs and derived proxies (e.g., crenarchaeol concentration, BIT index and IR6Me) display strong ∼ 23 kyr periodicity, likely reflecting the predominantly precession-driven insolation forcing of Quaternary climate variability in low-latitude regions. Our results suggest that GDGT-based temperature and moisture-balance proxies in Lake Chala sediments reflect the climate history of eastern equatorial Africa from at least ca. 160 ka onwards, i.e., covering the complete last glacial-interglacial cycle and the penultimate glacial maximum. This work confirms the potential of lacustrine GDGTs for elucidating the climate history of tropical regions at Quaternary timescales, provided they are applied to suitably high-quality sediment archives. Additionally, their interpretation should incorporate a broader understanding of the extent to which lake-system evolution limits the extrapolation back in time of proxy-climate relationships established in the modern system. © 2024 Copernicus Publications. All rights reserved. Article 2024 10.5194/bg-21-2877-2024 Biogeosciences 21 Copernicus Publications 2877 – 2908 11 Arequipa [Peru]; Chala; Peru; biomarker; climate variation; crater lake; ether; glacial-interglacial cycle; lacustrine deposit; paleoclimate; proxy climate record; seismic reflection; stratification https://www.scopus.com/inward/record.uri?eid=2-s2.0-85196263552&doi=10.5194%2fbg-21-2877-2024&partnerID=40&md5=17a3af88d40ef461463988be3c6b5d5a Cited by: 1 Allix J. Baxter Francien Peterse Dirk Verschuren Aihemaiti Maitituerdi Nicolas Waldmann Jaap S. Sinninghe Damsté article Fu2024 Article 2024 10.1016/j.jseaes.2023.105913 Journal of Asian Earth Sciences 259 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85176332010&doi=10.1016%2fj.jseaes.2023.105913&partnerID=40&md5=62a6feb90e8dbc7d2f2d7d3e25569ae1 Cited by: 1 Yu Fu Rihui Cheng Youfeng Gao Yang Zhou Zhongjie Xu article Zhang2024429 Article 2024 10.12097/gbc.2021.09.018 Geological Bulletin of China 43 429 – 442 2-3 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85189082202&doi=10.12097%2fgbc.2021.09.018&partnerID=40&md5=56f455bcdc224d9f1b4839276e52d1a5 Cited by: 0 Dejun Zhang Yuejuan Zheng Shuqin Zhang Jian Zhang Xin Huang Shuwang Chen Lei Sun article Pieńkowski2024 The Cardigan Bay Basin (UK) may have functioned as a deep and narrow strait, and thereby influenced Early Jurassic oceanic circulation through the northern and southern Laurasian Seaway, and between Boreal and Peri-Tethys domains. Toarcian hemipelagic deposits of the basin in the Mochras borehole show strongly bioturbated contourite facies. Trace fossils are strongly dominated by Phycosiphon incertum (represented by four morphotypes), which was produced by opportunistic colonizers. Thalassinoides, Schaubcylindrichnus and Trichichnus are common (the latter is a deep-tier trace fossil produced by filamentous sulfide-oxidizing bacteria with a high tolerance for dysoxia), accompanied by less common Zoophycos, Planolites, Palaeophycus, Teichichnus, Rhizocorallium, Chondrites, and dwelling and resting structures, such as cf. Polykladichnus, Siphonichnus, Skolithos, Arenicolites, Monocraterion and Lockeia. Ichnological and lithological signals suggest repetitive fluctuations in benthic conditions attributed to a hierarchy of orbital cycles (precession and obliquity [4th order], short eccentricity [3rd order], long eccentricity [2nd order] and Earth–Mars secular resonance [1st order]). The Pliensbachian–Toarcian transition appears to be a significant palaeoceanographic turning point in the Cardigan Bay Basin, starting a CaCO3 decline, and with the most severe oxygen crisis of the Tenuicostatum Zone (here dysoxic but not anoxic) ending at the onset, in the early Serpentinum Zone (Exaratum Subzone), of the Toarcian negative carbon isotope excursion (To-CIE—linked with the Toarcian Oceanic Anoxic Event occurring in the lower part in the Serpentinum Zone). This trend contrasts with the prevalence of anoxia synchronous with the To-CIE in many other settings. Minor dysoxia returned to the Mochras setting in the latest Thouarsense to Dispansum zone interval. Extreme climate warming during the To-CIE may have enhanced and caused a reversal in the direction of deep marine circulation, improving oxygenation of the sea floor. Spectral analysis of binary data on ichnotaxa appearances gives high confidence in orbital signals and allows refined estimation of ammonite zones and the duration of the Toarcian (minimum ~ 9.4 Myr). (Figure presented.) © The Author(s) 2024. Article 2024 10.1186/s40645-024-00612-3 Progress in Earth and Planetary Science 11 Springer Science and Business Media Deutschland GmbH 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85188924463&doi=10.1186%2fs40645-024-00612-3&partnerID=40&md5=610c50abccae5af0603c1a98fdc4ed4b Cited by: 6; All Open Access, Gold Open Access, Green Open Access Grzegorz Pieńkowski Alfred Uchman Krzysztof Ninard Kevin N. Page Stephen P. Hesselbo article Trauth2024 Article 2024 10.1038/s41467-024-47921-1 Nature Communications 15 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85192235913&doi=10.1038%2fs41467-024-47921-1&partnerID=40&md5=e34d4275002ef654cfe951967b01386b Cited by: 5; All Open Access, Gold Open Access, Green Open Access Martin H. Trauth Asfawossen Asrat Markus L. Fischer Peter O. Hopcroft Verena Foerster Stefanie Kaboth-Bahr Karin Kindermann Henry F. Lamb Norbert Marwan Mark A. Maslin Frank Schaebitz Paul J. Valdes article Prause2024 Erratum 2024 10.1016/j.jvolgeores.2024.108135 Journal of Volcanology and Geothermal Research 452 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85198191576&doi=10.1016%2fj.jvolgeores.2024.108135&partnerID=40&md5=f0c94a34f31897a169386a45ef659a37 Cited by: 0 Simon Prause Tobias B. Weisenberger Barbara I. Kleine-Marshall Patrick Monien Concetta Rispoli Andri Stefánsson article WOS:000949573100037 2023 10.1029/2022GL101258 GEOPHYSICAL RESEARCH LETTERS 50 3 seismicity catalog; sea level change; hydrothermal region; strain; strainmeter; solid Earth tides P. Martínez-Garzón G. C. Beroza G. M. Bocchini M. Bohnhoff article Cohen2023 Article 2023 10.1016/j.quascirev.2023.108284 Quaternary Science Reviews 317 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85169614588&doi=10.1016%2fj.quascirev.2023.108284&partnerID=40&md5=1e22ea569972b7c69f374e184bb4fc8b Cited by: 3; All Open Access, Green Open Access Andrew S. Cohen Julia Manobianco David L. Dettman Bryan A. Black Catherine Beck Craig S. Feibel Josephine C. Joordens Bert Van Bocxlaer Hubert Vonhof article Han20231503 Article 2023 10.1111/1755-6724.15023 Acta Geologica Sinica (English Edition) 97 1503 – 1522 5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85175015513&doi=10.1111%2f1755-6724.15023&partnerID=40&md5=8e9007b5968d06323b43a0fca5d58265 Cited by: 1 Shuangbiao Han Jie Huang Chengshan Wang Jiayi Cui article Baxter2023336 Article 2023 10.1038/s41586-023-06272-5 Nature 620 336 – 343 7973 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85167528794&doi=10.1038%2fs41586-023-06272-5&partnerID=40&md5=8e53516a7526b366c7607694baf832b6 Cited by: 35; All Open Access, Green Open Access, Hybrid Gold Open Access A.J. Baxter D. Verschuren F. Peterse D.G. Miralles C.M. Martin-Jones A. Maitituerdi T. Meeren M. Van Daele C.S. Lane G.H. Haug D.O. Olago J.S. Sinninghe Damsté article Avendaño2023 Lake Chalco, in Central Mexico, has a long diatom record which provides an excellent opportunity to document the biotic and hydrological responses of this ecosystem to orbital- and millennial-scale climatic variability during the last 150 ka. Detrended correspondence analysis was used to evaluate the ecological turnover and to identify diatom species associations throughout the sequence. Millennial-scale climatic fluctuations were identified as peaks in freshwater (mostly small Fragilariaceae spp.) or as peaks in salt-tolerant species. At orbital scales, species turnover involved changes between freshwater assemblages dominated by Stephanodiscus spp. – small Fragilariaceae spp. – Cocconeis placentula, present during low-evaporation, cool intervals [late Marine Isotope Stage (MIS)6, MIS5d, MIS2] against salt-tolerant taxa, dominated by Stephanocyclus and Cyclotella spp., in higher evaporation, higher salinity conditions (MIS5e, MIS5c–a, MIS4, MIS3, early MIS1). Comparatively, MIS6 and MIS5d seem to have been cooler (~ −6 to −7 °C) and wetter than MIS2 (~ − 4 to −5 °C). In contrast, MIS5e and early MIS1 (11.5–6 ka) had similar warmer, low lake level, saline conditions. In addition, MIS5 was a period of intense climatic change associated with wide-amplitude orbital forcing that favored a Stephanocyclus–Cyclotella spp. ecological succession (S. meneghinianus, C. tlalocii, C. poyeka, S. quillensis). In contrast, smaller temperature changes were inferred during MIS4 and MIS3. © 2023 The Authors Journal of Quaternary Science Published by John Wiley & Sons Ltd. 2023 English 02678179 10.1002/jqs.3507 Journal of Quaternary Science John Wiley and Sons Ltd Posgrado de Ciencias de la Tierra, Instituto de Geofísica, Universidad Nacional Autónoma de México, Ciudad Universitaria, Ciudad de México, Mexico; Laboratorio de Paleolimnología, Instituto de Geofísica, Universidad Nacional Autónoma de México, Ciudad Universitaria, Ciudad de México, Mexico; Instituto de Geología, Universidad Nacional Autónoma de México, Ciudad Universitaria, Ciudad de México, Mexico https://www.scopus.com/inward/record.uri?eid=2-s2.0-85148423211&doi=10.1002%2fjqs.3507&partnerID=40&md5=0762f5ecd06019a136b1ec7e61275950 cited By 0 D. Avendaño M. Caballero B. Ortega-Guerrero S. Lozano-García article Guillerm2023 The lake level of the Dead Sea, Southern Levant, has fluctuated with an amplitude of ∼250 m in response to the last glacial-interglacial cycle. This exceptional sensitivity to climate change, and the availability of long sedimentary archives, make the Dead Sea a benchmark for long quantitative paleohydrological reconstructions. However, discontinuities and chronological uncertainties in the marginal sedimentary record have hampered the reconstruction of Dead Sea lake levels beyond the Last Glacial (70–14 ka before present, BP). Here, we apply a two-pronged methodology. First, we measure the lake water density along ICDP deep core 5017-1-A using a new method, Brillouin spectroscopy on two-phase halite fluid inclusions; we combine it with the composition of pore water and the thickness of halite layers in the core to reconstruct lake level, volume, mass balance and subsidence rate. Second, we tune the chronology of lake levels from outcrops by matching it to the chronology of the deep core. The resulting lake level reconstruction, spanning 237–70 ka BP, is validated by the excellent agreement between outcrop- and mass balance-based methodologies. It shows a long-term recession of the lake, its level decreasing from one interglacial to the other, down to a Holocene record low. There are two reasons for this lake level fall. First, with an average rate of 2.65 ± 0.15 m/ka, subsidence has outpaced sedimentation at least over the last ∼130 ka. Second, by reducing the solute inventory of the lake, massive halite precipitation events such as that of 131–116 ka BP have durably increased surface water activity and evaporation, and thus lowered the lake level, up to today. Conversely, our analysis suggests that, during 191–11 ka BP, the dissolution of Mount Sedom salt diapir and freshwater inflows provided to the lake about three times the mass of solute NaCl contained in the modern Dead Sea (in 1985). This massive solute influx, occurring mainly during glacial highstands, strongly contributed to lowering surface water activity and evaporation and, therefore, to increasing the lake volume. Our results suggest that Dead Sea lake levels are more accurately interpreted in terms of climatic change if surface water activity is taken into account. © 2023 Elsevier Ltd 2023 English 02773791 10.1016/j.quascirev.2023.107964 Quaternary Science Reviews 303 Elsevier Ltd Univ Lyon, Univ Lyon 1, ENSL, CNRS, LGL-TPE, Villeurbanne, F-69622, France; Institut Lumiére Matiére, Université de Lyon, Université Claude Bernard Lyon 1, CNRS, Institut Universitaire de France, Villeurbanne, 69622, France; The Dr. Moses Strauss Department of Marine Geosciences, Charney School of Marine Sciences, University of Haifa, Mount Carmel, Haifa, 31905, Israel; Department of Earth Sciences, University of Geneva, Rue des Maraîchers 13, Geneva, Switzerland; GFZ German Research Centre for Geosciences, Section Climate Dynamics and Landscape Evolution, Telegrafenberg, Potsdam, 14473, Germany; BRGM, 3 Avenue C. Guillemin, Orléans, 45000, France Chloride minerals; Climate change; Evaporation; Fluid inclusion; Glacial geology; Lakes; Mineralogy; Sedimentology; Subsidence, Dead sea; Eastern Mediterranean; Fluid inclusion; Lake levels; Last glacial; Late quaternary; Mass balance; Southern levants; Water activity; Water evaporation, Sodium chloride, chronology; climate change; diapir; evaporation; freshwater; halite; Holocene; interglacial; lake level; lake water; Last Glacial; mass balance; sedimentation; solute; spectroscopy, Dead Sea; Israel; Levant; Mediterranean Region; Mount Sedom; Southern District https://www.scopus.com/inward/record.uri?eid=2-s2.0-85148943981&doi=10.1016%2fj.quascirev.2023.107964&partnerID=40&md5=1886084ab493d2796ab9b99692e78e41 cited By 0 E. Guillerm V. Gardien N.D. Waldmann N.S. Brall D. Ariztegui M.J. Schwab I. Neugebauer A. Lach F. Caupin article Zhang2023 Article 2023 10.1016/j.cretres.2023.105543 Cretaceous Research 149 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85158838254&doi=10.1016%2fj.cretres.2023.105543&partnerID=40&md5=d631ee24f213b511bef16d2dbabe7bb5 Cited by: 3 Li Zhang Yongdong Wang Micha Ruhl Yanbin Zhu Haijun Li article Nisson20236163 Investigations of abiotic and biotic contributions to dissolved organic carbon (DOC) are required to constrain microbial habitability in continental subsurface fluids. Here we investigate a large (101-283 mg C/L) DOC pool in an ancient (>1Ga), high temperature (45-55 °C), low biomass (102-104 cells/mL), and deep (3.2 km) brine from an uranium-enriched South African gold mine. Excitation-emission matrices (EEMs), negative electrospray ionization (-ESI) 21 tesla Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR MS), and amino acid analyses suggest the brine DOC is primarily radiolytically oxidized kerogen-rich shales or reefs, methane and ethane, with trace amounts of C3-C6 hydrocarbons and organic sulfides. δ2H and δ13C of C1-C3 hydrocarbons are consistent with abiotic origins. These findings suggest water-rock processes control redox and C cycling, helping support a meagre, slow biosphere over geologic time. A radiolytic-driven, habitable brine may signal similar settings are good targets in the search for life beyond Earth. © 2023. Springer Nature Limited. Article 2023 English 20411723 10.1038/s41467-023-41900-8 Nature communications 14 NLM (Medline) 6163 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85173033706&doi=10.1038%2fs41467-023-41900-8&partnerID=40&md5=44971859742f636e33b15fa70f7022fc Cited by: 0; All Open Access, Gold Open Access Devan M. Nisson Clifford C. Walters Martha L. Chacón-Patiño Chad R. Weisbrod Thomas L. Kieft Barbara Sherwood Lollar Oliver Warr Julio Castillo Scott M. Perl Errol D. Cason Barry M. Freifeld Tullis C. Onstott article Luethje2023 Increasing surface air temperatures and human influences (e.g., agriculture, livestock grazing, tourism) are altering lacustrine ecosystems in the South American Andean páramo, and these influences are evident in changes in the diatom-species composition in sediment cores from the region that span the last ~ 150 years. Existing studies are limited by their short temporal scales and limited spatial extent. We analyzed two sediment cores spanning the last two millennia from the northern (Laguna Piñan) and southern (Laguna Fondococha) Andean páramo of Ecuador to provide a longer-term perspective on lake dynamics. Both lakes show shifts in the dominant diatoms through time. Fondococha diatoms shifted in dominance between two Aulacoseira species and in the planktic to benthic ratio, and these shifts are interpreted as evidence of changing lake level. The inferred shifts are corroborated by changes in sediment geochemistry. Piñan shows a directional shift in the diatom assemblage over the period of the record, from benthic diatoms tolerant of high dissolved organic carbon (DOC), low pH, and low nutrients, to an assemblage characteristic of lower DOC, Melina use only one higher for pH, nutrients and lake levels. Shifts in Piñan’s diatoms are correlated with tephra layers in the sediment, suggesting that local volcanic deposition may have been responsible for altering the catchment and lake geochemistry. This is supported by relatively high δ13C values in organic matter associated with tephra layers, which become more negative up-section. Our study suggests that remote lakes in spatially heterogenous montane regions act as sentinels of different facets of environmental change and provide insights into Andean ecosystem responses to environmental perturbations. © 2023, The Author(s), under exclusive licence to Springer Nature B.V. Article 2023 10.1007/s10933-022-00274-5 Journal of Paleolimnology https://www.scopus.com/inward/record.uri?eid=2-s2.0-85146337930&doi=10.1007%2fs10933-022-00274-5&partnerID=40&md5=bf4291475529a62f502fccd301c6c446 Cited by: 1 Melina Luethje Xavier Benito Tobias Schneider Pablo V. Mosquera Paul Baker Sherilyn C. Fritz article sd-32-85-2023 2023 10.5194/sd-32-85-2023 Scientific Drilling 32 85-100 J. Obrist-Farner A. Eckert P. M. J. Douglas L. Pérez A. Correa-Metrio B. L. Konecky T. Bauersachs S. Zimmerman S. Scheidt M. Brenner S. Kutterolf J. Maurer O. Flores C. M. Burberry A. Noren A. Myrbo M. Lachniet N. Wattrus D. Gibson the LIBRE scientific team article Decrausaz2023171 Earth's long-term cycling of carbon is regulated from mid-ocean ridges to convergent plate boundaries by mass transfers involving mantle rocks. Here we examine the conversion of peridotite to listvenite (magnesite + quartz rock) during CO2 metasomatism along the basal thrust of the Semail Ophiolite (Fanja, Sultanate of Oman). At the outcrop scale, this transformation defines reaction zones, from serpentinized peridotites to carbonated serpentinites and listvenites. Based on a detailed petrological and chemical study, we show that carbonation progressed through three main stages involving the development of replacive textures ascribed to early stages, whilst carbonate (± quartz) veining becomes predominant in the last stage. The pervasive replacement of serpentine by magnesite is characterized by the formation of spheroids, among which two types are identified based on the composition of their core regions: Fe-core and Mg-core spheroids. Fe zoning is a type feature of matrix and vein magnesite formed during the onset carbonation (Stage 1). While Fe-rich magnesite is predicted to form at low fluid XCO2 from a poorly to moderately oxidized protolith, our study evidences that the local non-redox destabilization of Fe oxides into Fe-rich magnesite is essential to the development of Fe-core spheroids. The formation of Fe-core spheroids is followed by the pervasive (over-)growth of Mg-rich spheroids and aggregates (Stage 2) at near-equilibrium conditions in response to increasing fluid XCO2. Furthermore, the compositions of carbonates indicate that most siderophile transition elements released by the dissolution of primary minerals are locally trapped in carbonate and oxides during matrix carbonation, while elements with a chalcophile affinity are the most likely to be leached out of reaction zones. © 2023 Thierry Decrausaz et al. Article 2023 10.5194/ejm-35-171-2023 European Journal of Mineralogy 35 Copernicus Publications 171 – 187 2 Oman; Semail Ophiolite; Iron oxides; Magnesite; Quartz; Serpentine; Textures; Zoning; Chemical zoning; Convergent plate boundaries; Last stage; Mantle rocks; matrix; Mid-ocean-ridge; Quartz rocks; Reaction zones; Serpentinized peridotites; Sultanate of Oman; carbonate; iron; manganese; metasomatism; mid-ocean ridge; peridotite; quartz vein; ultramafic rock; Carbonation https://www.scopus.com/inward/record.uri?eid=2-s2.0-85151426343&doi=10.5194%2fejm-35-171-2023&partnerID=40&md5=7f83598ece0fedfe26332025aca776bf Cited by: 5; All Open Access, Gold Open Access Thierry Decrausaz Marguerite Godard Manuel D. Menzel Fleurice Parat Emilien Oliot Romain Lafay Fabrice Barou article Lozhkin2023 Palynological analysis of Early Pleistocene sediments from Lake El'gygytgyn indicate that climate was warmer than present between c. 1.2860 and 1.6975 Ma (late Gelisian–early Calabrian ages), although variations in the paleovegetation indicate fluctuations between relatively cool and warm conditions. During the coolest intervals, the vegetation on the Anadyr Plateau was a mix of Betula-Salix shrub tundra and Larix forest-tundra. Larix forests, which probably included trees species of Betula and Alnus, characterized the regional vegetation during the warmest times. Slightly cooler interglaciations are indicated by the presence of Larix-forest tundra. Pinus pumila pollen is not consistently present in all interglaciations, indicating that variations in the extent and/or duration of snow cover occurred during these warm intervals. The absence of pollen from this evergreen shrub contrasts with Holocene and Late Pleistocene assemblages, where the taxon is a hallmark of warm conditions. During the Early Pleistocene, Betula pollen indicates the plant's presence during warm and cool intervals, in contrast to Late and Middle Pleistocene spectra where shrub Betula is absent or rare. The pollen data from MIS 55 suggest that it was the coolest of the Pleistocene “super” interglaciations and that the MIS 43 climate was as warm as that of MIS 55. The El'gygytgyn palynological record is a powerful reminder that the distribution of arctic communities can be vastly reduced or eradicated during warm Earth scenarios. © 2023 Elsevier B.V. Article 2023 10.1016/j.revpalbo.2023.104904 Review of Palaeobotany and Palynology 315 Elsevier B.V. Anadyr; Arctic; Chukchi; Elgygytgyn Lake; Russian Federation; Calabrian; paleoclimate; palynology; plant community; Pleistocene; pollen; shrub; vegetation history https://www.scopus.com/inward/record.uri?eid=2-s2.0-85159775840&doi=10.1016%2fj.revpalbo.2023.104904&partnerID=40&md5=00be69ce45e02906b2c8c61e56a79c5d Cited by: 1; All Open Access, Bronze Open Access Anatoly V. Lozhkin Patricia M. Anderson article McHenry202396 The eastern branch of the East African Rift System hosts many shallow modern lakes and paleolakes, which can be sensitive recorders of changing climate conditions (complicated by tectonics) during the past few million years. However, many of such lakes are saline–alkaline (salty and high pH), and these conditions do not easily preserve pollen and other biologically derived paleoclimate indicators. Fortunately, some preserved minerals that formed in these extreme environments reflect subtle shifts in lake water chemistry (controlled by changes in climate conditions) and therefore provide a continuous record of local and regional climate change. We present two different mineral proxies (zeolites and clays) from two different paleolake basins (Olduvai Gorge, Tanzania, and Chew Bahir, Ethiopia) as examples. © 2023 Mineralogical Society of America. All rights reserved. Article 2023 10.2138/gselements.19.2.96 Elements 19 Mineralogical Society of America 96 – 103 2 East African Rift; Alkalinity; Climate change; Lakes; Zeolites; Alkalines; Changing climate; Climate; Climate condition; Condition; East African Rift; Eastern Africa; High pH; Paleolake; Rift systems; clay mineral; climate change; lake water; paleoclimate; paleoenvironment; water chemistry; zeolite; Clay minerals https://www.scopus.com/inward/record.uri?eid=2-s2.0-85164968949&doi=10.2138%2fgselements.19.2.96&partnerID=40&md5=3a96dc4973c0abbcc950c54c8170ad80 Cited by: 2 Lindsay J. McHenry Verena Foerster Daniel Gebregiorgis article WOS:000965176200001 2023 10.1016/j.gloplacha.2023.104058 GLOBAL AND PLANETARY CHANGE 222 Mesozoic -Paleogene; Hyperthermal events; Climate change; Paleoenvironment Tianchen He David B. Kemp Juan Li Micha Ruhl article Akamatsu2023 Article 2023 10.1029/2022GC010792 Geochemistry, Geophysics, Geosystems 24 6 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85163692922&doi=10.1029%2f2022GC010792&partnerID=40&md5=f8272e40077da840d9e187196ee444cb Cited by: 2; All Open Access, Gold Open Access Y. Akamatsu I. Katayama K. Okazaki K. Michibayashi article Verhagen2023 Article 2023 10.3390/min13030353 Minerals 13 3 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85152396344&doi=10.3390%2fmin13030353&partnerID=40&md5=78ec2df264b41083ea2c422bb305a1dd Cited by: 1; All Open Access, Gold Open Access Christina M. Verhagen Ji-In Jung Sonia M. Tikoo Axel Wittmann David A. Kring Stefanie Brachfeld Laying Wu Dale H. Burns Sean P. S. Gulick article Paulsen2023 Article 2023 10.1002/spp2.1489 Papers in Palaeontology 9 2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85153760457&doi=10.1002%2fspp2.1489&partnerID=40&md5=0803202743c4d4224dc5e30897511b8c Cited by: 3; All Open Access, Hybrid Gold Open Access Maria Paulsen Nicolas Thibault article WOS:000904613800008 2023 10.1016/j.epsl.2022.117959 EARTH AND PLANETARY SCIENCE LETTERS 602 Wenhan Chen David B. Kemp Tianchen He Robert J. Newton Yijun Xiong Hugh C. Jenkyns Kentaro Izumi Tenichi Cho Chunju Huang Simon W. Poulton article WOS:000921452700001 2023 10.1016/j.quascirev.2022.107935 QUATERNARY SCIENCE REVIEWS 301 Quaternary geochronology; Zircon; (UeTh)/He; SIMS; Central America; 40Ar/39Ar A. Cisneros Leon M. Danisik J. C. Schindlbeck-Belo S. Kutterolf A. K. Schmitt A. Freundt J. Kling K. -L. Wang H. -Y. Lee article WOS:000969084500001 2023 10.1029/2023JB026677 JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH 128 4 Peter B. Kelemen Jurg M. Matter Damon A. H. Teagle Jude A. Coggon Marguerite Godard Katsuyoshi Michibayashi Eiichi Takazawa Alexis S. Templeton Ken Williams Zaher Al Sulaimani article Gao2023425 The internationally recognized absolute isotopic age of the Upper-Lower Cretaceous stratigraphic boundary is 100.5 Ma, and the Global Boundary Stratotype Section and Points (GSSP) for the boundary is placed in marine strata; however, there have been no reports of GSSP ("golden spikes") for terrestrial boundaries anywhere in the world. The terrestrial Upper-Lower Cretaceous stratigraphic boundary is of great value in understanding the evolution of paleogeography, paleoenvironment and paleoclimate on land under the greenhouse conditions in the Middle Cretaceous, and the ideal geological records for studying this boundary may be found in the Songliao Basin, northeastern China, where a complete set of Cretaceous continental strata are developed. Here, we investigated the rock types, lithologic sequence and sedimentary facies in the core section of International Continental Scientific Drilling Program (ICDP) borehole SK-3, southern Songliao Basin. Based on the core description, gray and gray-green rhyolitic lithic crystalline tuffite deposit is found in the coastal-shallow lacustrine sedimentary sequences of the upper part of the second member of the Quantou Formation at 1191. 6 m depth. The tuffite deposit, according to zircon U-Pb dating of its syndepositional magmatic components, has an zircon age of (96.8±2.9) Ma and belongs to the Middle-Cenomanian period. Combined with previous data, the deposition rate for the Quantou-Denglouku Formations in the study area is 90. 54-110 m/Ma, and we conclude accordingly that the Upper-Lower Cretaceous stratigraphic boundary is located in the middle of the first member of the Quantou Formation in borehole SK-3 (at 1526.6-1598. 6 m depth). Considering analytical errors in the age-dating results, the Upper-Lower Cretaceous stratigraphic boundary in borehole SK-3 is independently calculated to be between the middle of the second member of the Quantou Formation and the upper part of the fourth member of the Denglouku Formation (at 1279. 6-1917. 6 m depth). Other researchers have tentatively placed the boundary in the Denglouku Formation based on the chronological data of ICDP borehole SK-1 and SK-2, northern Songliao Basin. The continuous coring data reveal continuous fluvial-lacustrine sedimentary sequences in the Denglouku - Quantou Formations in borehole SK-3; while results of seismic horizon matching further suggest the Denglouku - Quantou Formations are widely developed across the Songliao Basin and sedimentary records of continuous deposition are widespread. Therefore, the Denglouku - Quantou Formations across the basin should provide the geological record of continuous deposition of the Upper-Lower Cretaceous stratigraphic boundary. And this paper provides the basic dataset and exploration direction to find the "golden spikes" for the Upper and Lower Cretaceous continental stratigraphic boundary in the Songliao Basin and adjacent areas. © 2023 Science Frontiers editorial department. All rights reserved. Article 2023 Chinese 10052321 10.13745/j.esf.sf.2023.1.28 Earth Science Frontiers 30 Science Frontiers editorial department 425 – 440 3 Binary alloys; Boreholes; Deposits; Geochronology; Infill drilling; Isotopes; Lead alloys; Sedimentary rocks; Sedimentology; Stratigraphy; Zircon; Continental scientific drillings; Cretaceous denglouku - quantou formation; Denglouku formations; Drilling projects; International continental scientific drilling program borehole SK-3; Lower Cretaceous; Potential global boundary stratotype section and point golden spike in terrestrial stratum; Songliao basin; Upper and low cretaceous stratigraphic boundary; Upper Cretaceous; Deposition rates https://www.scopus.com/inward/record.uri?eid=2-s2.0-85159090720&doi=10.13745%2fj.esf.sf.2023.1.28&partnerID=40&md5=8683ea2043558af11933780d188c708d Cited by: 0 Hang Gao Pujun Wang Youfeng Gao Xiaoqiao Wan Guang Yang Jingsong Hu Huaichun Wu article Xu2023 Article 2023 10.1016/j.chemgeo.2023.121790 Chemical Geology 642 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85178892134&doi=10.1016%2fj.chemgeo.2023.121790&partnerID=40&md5=87eec4ff10d4e563da6f7f17ef46bd2d Cited by: 6 Yilun Xu Dandan Li Yuan Gao Menghan Li Lilin Sun Xiaolin Zhang Chengshan Wang Yanan Shen article sd-32-61-2023 2023 10.5194/sd-32-61-2023 Scientific Drilling 32 61-72 A. J. Smith E. Ito N. Burls L. Clarke T. Donders R. Hatfield S. Kuehn A. Koutsodendris T. Lowenstein D. McGee P. Molnar A. Prokopenko K. Snell B. Valero Garcés J. Werne C. Zeeden Consortium article sd-32-73-2023 2023 10.5194/sd-32-73-2023 Scientific Drilling 32 73-84 S. Kutterolf M. Brenner R. A. Dull A. Freundt J. Kallmeyer S. Krastel S. Katsev E. Lebas A. Meyer L. Pérez J. Rausch A. Saballos A. Schwalb W. Strauch article WOS:001073435900001 2023 10.1016/j.marpetgeo.2023.106493 MARINE AND PETROLEUM GEOLOGY 157 Yingcheng formation; Strike-slip faulting; Songliao basin; End of continental rifting; Early cretaceous; SK-2 Ye Wang Rihui Cheng Yanjie Shen Yu Fu Zhongjie Xu Youfeng Gao article Pickarski2023 Article 2023 10.1038/s43247-023-00827-0 Communications Earth and Environment 4 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85159680680&doi=10.1038%2fs43247-023-00827-0&partnerID=40&md5=139a30871657284ed406c2ab4fd9802a Cited by: 5; All Open Access, Gold Open Access Nadine Pickarski Ola Kwiecien Thomas Litt article Damaschke202377 Article 2023 10.1144/SP527-2022-58 Geological Society Special Publication 527 77 – 94 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85178654829&doi=10.1144%2fSP527-2022-58&partnerID=40&md5=b8d4c92d7f509d3e950336102cc2c832 Cited by: 8; All Open Access, Hybrid Gold Open Access M. Damaschke M.W. Fellgett M.P.A. Howe C.J. Watson article Boateng2023 Review 2023 10.1016/j.sciaf.2023.e01893 Scientific African 21 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85171385124&doi=10.1016%2fj.sciaf.2023.e01893&partnerID=40&md5=783073e1966dd8cbce25c22a7c967e11 Cited by: 2; All Open Access, Gold Open Access Cyril D. Boateng Christopher A. Akurugu David D. Wemegah Sylvester K. Danuor article WOS:001042207400001 2023 10.1029/2023EA003009 EARTH AND SPACE SCIENCE 10 8 maar-diatreme volcano; magnetometry; electrical resistivity tomography; drilling; gravity survey; Eger Rift Pavla Hrubcová Tomáš Fischer Vladislav Rapprich Jan Valenta Petr Tábořík Jan Mrlina Torsten Dahm Tomáš Vylita Roman Beranek Radek Klanica Josef Vlček Veronika Turjaková article Sohn2023 Article 2023 10.1016/j.hydroa.2023.100163 Journal of Hydrology X 21 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85173040843&doi=10.1016%2fj.hydroa.2023.100163&partnerID=40&md5=4786b0ec97f6e9c70fcf03357efe2824 Cited by: 1; All Open Access, Gold Open Access R.A. Sohn J.M. Matter article Qin2024168 Article 2023 10.3975/cagsb.2022.121901 Acta Geoscientica Sinica 44 21-32 01 G. Wang F. Ma H. Hou G. Jiang X. Zhang R. Yuan C. Li article Bassez20231 Article 2023 10.1007/s11084-023-09638-x Origins of Life and Evolution of Biospheres 53 1 – 41 1-2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85168101645&doi=10.1007%2fs11084-023-09638-x&partnerID=40&md5=c98c48e68b6751c833b95745209ec3e8 Cited by: 0; All Open Access, Hybrid Gold Open Access Marie-Paule Bassez article Garroni2023834 Carbonates from the impact melt-bearing breccia in the 2016 IODP/ICDP Expedition 364 drill core at Site M0077 were systematically documented and characterized petrographically and geochemically. Calcite, the only carbonate mineral present, is abundant throughout this deposit as five distinct varieties: (1) subangular carbonate clasts (Type A); (2) subround/irregular carbonate clasts with clay altered rims (Type B); (3) fine-crystalline matrix calcite (Type C); (4) void-filling sparry calcite (Type D); and (5) microcrystalline carbonate with flow textures (Type E). Quantitative geochemical analysis shows that calcite in all carbonate varieties are low in elemental impurities (<2.0 cumulative wt% on average); however, relative concentrations of MgO and MnO vary, which provides distinction between each variety: MgO is highest in calcite from Types A, B, and C carbonates (0.2–0.8 wt% on average); MnO is highest in calcite from Types B, C, and D carbonates (0.2–1.3 wt% on average); and calcite from Type E carbonate is most pure (<0.1 wt% on average MgO and MnO, cumulatively). Based on textural and geochemical variations between carbonate types, we interpret that some of the carbonate target rocks melted during impact and were immiscible within the silicate-dominated melt sheet prior to the resurgence of seawater. Type B clasts were formed by molten fuel–coolant interaction, as the incoming seawater eroded through the melt sheet and encountered carbonate melt (Type E). Post-impact meteoric-dominated hydrothermal activity produced the Mn-elevated calcite from Type C and D carbonates, and altered the Type B clasts to be elevated in Mn and host a clay-rich rim. © 2023 The Authors. Meteoritics & Planetary Science published by Wiley Periodicals LLC on behalf of The Meteoritical Society. Article 2023 10.1111/maps.13993 Meteoritics and Planetary Science 58 University of Arkansa 834 – 854 6 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85159801790&doi=10.1111%2fmaps.13993&partnerID=40&md5=d015aab37a5d37b12929852e8299cd96 Cited by: 1; All Open Access, Hybrid Gold Open Access Nicolas D. Garroni Gordon R. Osinski article Wagner20231 Studies of the upper 447 m of the DEEP site sediment succession from central Lake Ohrid, Balkan Peninsula, North Macedonia and Albania provided important insights into the regional climate history and evolutionary dynamics since permanent lacustrine conditions established at 1.36 million years ago (Ma). This paper focuses on the entire 584-m-long DEEP sediment succession and a comparison to a 197-m-long sediment succession from the Pestani site ~5 km to the east in the lake, where drilling ended close to the bedrock, to unravel the earliest history of Lake Ohrid and its basin development. 26Al/10Be dating of clasts from the base of the DEEP sediment succession implies that the sedimentation in the modern basin started at c. 2 Ma. Geophysical, sedimentological and micropalaeontological data allow for chronological information to be transposed from the DEEP to the Pestani succession. Fluvial conditions, slack water conditions, peat formation and/or complete desiccation prevailed at the DEEP and Pestani sites until 1.36 and 1.21 Ma, respectively, before a larger lake extended over both sites. Activation of karst aquifers to the east probably by tectonic activity and a potential existence of neighbouring Lake Prespa supported filling of Lake Ohrid. The lake deepened gradually, with a relatively constant vertical displacement rate of ~0.2 mm a−1 between the central and the eastern lateral basin and with greater water depth presumably during interglacial periods. Although the dynamic environment characterized by local processes and the fragmentary chronology of the basal sediment successions from both sites hamper palaeoclimatic significance prior to the existence of a larger lake, the new data provide an unprecedented and detailed picture of the geodynamic evolution of the basin and lake that is Europe’s presumed oldest extant freshwater lake. © 2022 The Authors. Boreas published by John Wiley & Sons Ltd on behalf of The Boreas Collegium. Article 2023 English 03009483 10.1111/bor.12601 Boreas 52 John Wiley and Sons Inc 1 – 26 1 Balkan; Lake Ohrid; Turkmenistan; clast; displacement; geodynamics; lacustrine deposit; lake evolution; limnology; sedimentation; sedimentology https://www.scopus.com/inward/record.uri?eid=2-s2.0-85141222203&doi=10.1111%2fbor.12601&partnerID=40&md5=200d6189548dbe39bb8ed48002df5cc4 Cited by: 2; All Open Access, Green Open Access, Hybrid Gold Open Access Bernd Wagner Paul Tauber Alexander Francke Niklas Leicher Steven A. Binnie Aleksandra Cvetkoska Elena Jovanovska Janna Just Jack H. Lacey Zlatko Levkov Katja Lindhorst Katerina Kouli Sebastian Krastel Konstantinos Panagiotopoulos Arne Ulfers Dušica Zaova Timme H. Donders Andon Grazhdani Andreas Koutsodendris Melanie J. Leng Laura Sadori Mirko Scheinert Hendrik Vogel Thomas Wonik Giovanni Zanchetta Thomas Wilke article Simpson2023554 Article 2023 10.1093/gji/ggad237 Geophysical Journal International 235 554 – 565 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85164534524&doi=10.1093%2fgji%2fggad237&partnerID=40&md5=5bd90bdbd75e7c6fdb6bade70ef4fe9c Cited by: 2; All Open Access, Hybrid Gold Open Access Jonathan Simpson Alison E. Malcolm Kasper Wijk article deGraaff2023 Impact events that create complex craters excavate mid- to lower-crustal rocks, offering a unique perspective on the interior composition and internal dynamics of planetary bodies. On the Yucatán Peninsula, Mexico, the surface geology mainly consists of ∼3 km thick sedimentary rocks, with a lack of exposure of crystalline basement in many areas. Consequently, current understanding of the Yucatán subsurface is largely based on impact ejecta and drill cores recovered from the 180–200-km-diameter Chicxulub impact structure. In this study, we present the first apatite and titanite U–Pb ages for pre-impact dacitic, doleritic, and felsitic magmatic dikes preserved in Chicxulub's peak ring sampled during the 2016 IODP-ICDP Expedition 364. Dating yielded two age groups, with Carboniferous dacites (328–318 Ma) and a felsite (330± 9 Ma) overlapping in age with most of the granitoid basement sampled in the Expedition 364 drill core, as well as Jurassic dolerites (169–159 Ma) and a felsite (158 ± 19 Ma) that represent the first in situ sampling of Jurassic-age magmatic intrusions for the Yucatán Peninsula. Further investigation of the Nd, Sr, and Hf isotopic compositions of these pre-impact lithologies and impact melt rocks from the peak ring structure suggest that dolerites generally contributed up to ∼10 vol% of the Chicxulub impact melt rock sampled in the peak ring. This percentage implies that the dolerites comprised a large part of the Yucatán subsurface by volume, representing a hitherto unsampled pervasive Jurassic magmatic phase. We interpret this magmatic phase to be related to the opening of the Gulf of Mexico, representing the first physical sampling of lithologies associated with the southern extension of the opening of the Gulf of Mexico and likely constraining its onset to the Late Middle Jurassic. © 2022 Elsevier B.V. 2023 10.1016/j.lithos.2022.106953 Lithos 436-437 Research Unit: AMGC, Department of Chemistry, Vrije Universiteit Brussel, Pleinlaan 2, Brussels, 1050, Belgium; Laboratoire G-Time, Université Libre de Bruxelles, ULB, Av. F.D. Roosevelt 50, Brussels, 1050, Belgium; Institute for Geophysics & Department of Geological Sciences, Jackson School of Geosciences, University of Texas at Austin, Austin, TX 78758, United States; Department of Lithospheric Research, University of Vienna, Althanstrasse 14, Vienna, A-1090, Austria; Center for Planetary Systems Habitability, University of Texas at Austin, Austin, TX 78712, United States; Natural History Museum Vienna, Burgring 7, Vienna, A-1010, Austria https://www.scopus.com/inward/record.uri?eid=2-s2.0-85144048390&doi=10.1016%2fj.lithos.2022.106953&partnerID=40&md5=bfb7cf67afebeed12f538bf2ec24382f cited By 0 S.J. Graaff C.H. Ross J.-G. Feignon P. Kaskes S.P.S. Gulick S. Goderis T. Déhais V. Debaille L. Ferrière C. Koeberl N. Mattielli D.F. Stockli P. Claeys article Beccaletto2023163 Article 2023 10.5802/crgeos.246 Comptes Rendus - Geoscience 355 163 – 190 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85187526345&doi=10.5802%2fcrgeos.246&partnerID=40&md5=8d47a0fab063a0e0c7de9713f0527c87 Cited by: 1; All Open Access, Gold Open Access, Green Open Access Laurent Beccaletto Sylvie Bourquin article Wang2023 Organic carbon (OC) burial in lakes has been identified as an efficient sink in the global carbon cycle. Abundant input of terrestrial-derived OC leads to high variability in OC origin and type, but its role in determining organic-rich sediments has been overlooked in prior studies. Here, we investigated the OC source and concentration of the Lower Cretaceous (Middle Aptian to Lower Albian) Shahezi Formation (Songliao Basin, NE Asia) to reveal the burial of terrestrial OC in relation to syn-rift lake evolution and paleoclimate change. The sequence stratigraphic framework of fan-deltaic and lacustrine successions was established by identifying depositional facies and sequence boundaries. The lacustrine-dominated interval was further subdivided into four facies associations (i.e., lake shore to littoral siltstones, shallow-littoral mudstones, sublittoral, and profundal) and a few cyclic, parasequence-order packages, using 90 m of continuous cores and high sampling frequency of RoqSCAN SEM-EDS. Multiple independent proxies (macerals identified using correlative light and electron microscopy, pyrolysis indices, Ro, TOC/TN, and δ13Corg) suggest that the organic fraction of the highly mature mudstones was predominantly contributed by terrestrial-derived OC (gas-prone type III/IV kerogen). A direct correlation between depositional facies, chemical weathering proxies (CIA, CIAcorr, and Ln(Al2O3/Na2O)), and OC burial (TOC and HI) has been established. A steep syn-rift slope, a warm–humid climate, abundant vegetation, and the subaqueous transport of OC-bearing sediments (e.g., massive mud-rich conglomerates and sand- to pebble-bearing mudstones), may have jointly promoted the high input of terrestrial OC. A comparison between two Lower Cretaceous terrestrial records from high and low paleolatitudes suggests that the shift from the syn-rift to post-rift phase was accompanied by an increase in TOC concentration and a change toward Type I kerogen of aquatic origin. The tectonically-controlled evolution of rift basins might be an important forcing function for the change of OC sources and concentrations, which is responsible for long-term OC burial in hinterland environments. © 2023 Article 2023 10.1016/j.sedgeo.2023.106472 Sedimentary Geology 455 Elsevier B.V. China; Songliao Basin; Alumina; Aluminum oxide; Deposition; Kerogen; Lakes; Oil shale; Stratigraphy; Weathering; Carbon concentrations; Carbon source; Chemical weathering; Littorals; Lower Cretaceous; Mudstone; Organic carbon burial; Paleoclimates; Rift basin; Syn-rift; chemical weathering; climate variation; correlation; Cretaceous; depositional sequence; lacustrine deposit; lake evolution; mudstone; organic carbon; paleoclimate; sequence stratigraphy; Organic carbon https://www.scopus.com/inward/record.uri?eid=2-s2.0-85169617226&doi=10.1016%2fj.sedgeo.2023.106472&partnerID=40&md5=78e9eae25d760fa017b82a33eb47fe35 Cited by: 1 Qianyou Wang Yaohua Li James E.P. Utley Joe Gardner Bei Liu Jianfang Hu Longyi Shao Xin Wang Fenglin Gao Dadong Liu Haibin Li Zhenxue Jiang Richard H. Worden article Qin2024168 Article 2023 10.12143/j.ztgc.2023.S1.019 Exploration Engineering 50 126-134 S1 L. Sun X. Ling D. Guan Q. Zhou Z. Fan B. Liu article Plümper2023165 Olivine is the main component of the Earth’s upper mantle, on which our tectonic plates rest. As such, olivine has been studied since the dawn of geology and is regarded as the storyteller of the Earth’s interior. Its physical and chemical properties provide insight into its creation in magmas and its voyage through the upper mantle. However, when olivine is exposed to aqueous fluids, it adopts a more rebellious, rock star–like disposition. Here, we show that the discord, or disequilibrium, between olivine, its reaction products, and fluids containing water and carbon dioxide is so significant that it has been instrumental in changing the Earth throughout the planet’s history and will continue to do so well into the future. © 2023 Mineralogical Society of America. All rights reserved. Article 2023 10.2138/gselements.19.3.165 Elements 19 Mineralogical Society of America 165 – 172 3 Carbon dioxide; Earth (planet); Olivine; Stars; Alteration; Aqueous fluids; Exposed to; Physical and chemical properties; Star-like; Tectonic plates; Upper mantle; carbon dioxide; chemical alteration; olivine; serpentine; upper mantle; Serpentine https://www.scopus.com/inward/record.uri?eid=2-s2.0-85173609187&doi=10.2138%2fgselements.19.3.165&partnerID=40&md5=3cc68f775bb654b43797d7724f0a6fca Cited by: 2; All Open Access, Green Open Access Oliver Plümper Juerg Matter article WOS:000976645200001 2023 10.3389/fmicb.2023.1138656 FRONTIERS IN MICROBIOLOGY 14 subsurface; serpentinite; recombination; evolution; geographic isolation; parapatric speciation; dispersal limitation; competitive exclusion Mason Munro-Ehrlich Daniel B. Nothaft Elizabeth M. Fones Juerg M. Matter Alexis S. Templeton Eric S. Boyd article Martínez-Abarca20231409 Lake Petén Itzá (Guatemala) possesses one of the longest lacustrine sediment records in the northern Neotropics, which enabled study of paleoclimate variability in the region during the last ∼400000 years. We used geochemical (Ti, Ca/(Ti+Fe) and Mn/Fe) and mineralogical (carbonates, gypsum, quartz, clay) data from sediment core PI-2 to infer past changes in runoff, lake evaporation, organic matter sources and redox conditions in the water column, caused by hydrological changes in the northern Neotropics during Marine Isotope Stages (MISs) 3-2. From 59 to 39 cal ka BP climate conditions were relatively wet, and the lake was marked by higher primary productivity and anoxic bottom waters. This wet environment was interrupted for two periods of possible low water level at 52 and 46 cal ka BP, when our data suggest higher evaporation, high terrestrial organic matter input and persistent oxic conditions. Between 39 and 23 cal ka BP, evaporation and input of terrestrial organic matter increased considerably, lake level declined, and lake bottom waters generally became oxic. These conditions reversed during the Last Glacial Maximum (23.5-18.0 cal ka BP), when runoff and lake productivity increased, and rising lake level caused bottom waters to again become anoxic. Comparison of our hydrologic proxy data with sea surface temperature anomalies between the eastern Pacific and the Caribbean suggests that changes in the intensity of the Caribbean Low-Level Jet (CLLJ) may have influenced long-term changes in runoff during MISs 3-2. Higher intensity of the CLLJ during the onset of MIS 3 and the LGM might have led to greater runoff into the lake, whereas the MIS 3-2 transition experienced a weaker CLLJ and consequently less runoff. A refined, high-resolution age-depth model for the PI-2 sediment core enabled us to identify millennial-scale Greenland interstadials (GIs) 14-2, Greenland stadials (GSs) 14-2 and Heinrich stadials (HSs) 5-1. In general, HSs and GSs were characterized by drier conditions. In contrast to GSs and HSs, GIs were characterized by greater runoff and overall wetter conditions, with the most pronounced GI peaks between 40 and 30 cal ka BP. Whereas GSs 9, 8, 7 and 6 began with abrupt increases in evaporation and ended with gradual increases in humidity, GSs 11 and 10 showed reversed patterns. The Lake Petén Itzá paleohydrology record, along with other regional paleoclimate records, led us to conclude that shifts in the position of the Intertropical Convergence Zone (ITCZ) altered moisture delivery to the lake on millennial timescales. During GSs and HSs, high evaporation from Petén Itzá (dry climate conditions) was associated with a more southerly position of the ITCZ, whereas wetter GIs prevailed during a more northerly ITCZ position. Although abrupt millennial-scale shifts in ITCZ and hydroclimate between GSs/HSs and GIs can be linked to instabilities in the Atlantic Meridional Overturning Circulation (AMOC), longer-term changes were additionally influenced by changes in atmospheric convection linked to modulations of the CLLJ in response to ΔSST between the equatorial Pacific and tropical Atlantic. © 2023 Rodrigo Martínez-Abarca et al. Article 2023 10.5194/cp-19-1409-2023 Climate of the Past 19 Copernicus Publications 1409 – 1434 7 Atlantic Ocean; Atlantic Ocean (Tropical); Guatemala [Central America]; Lake Peten Itza; Pacific Ocean; Pacific Ocean (Equatorial); Peten; Atlantic Multidecadal Oscillation; atmospheric convection; climate conditions; climate variation; hydrological change; intertropical convergence zone; lacustrine deposit; marine isotope stage; Neotropical Region; overturn; paleoclimate; primary production; redox conditions; sediment core https://www.scopus.com/inward/record.uri?eid=2-s2.0-85169905724&doi=10.5194%2fcp-19-1409-2023&partnerID=40&md5=4cce60068015bdb1e83c4241b83a4565 Cited by: 0 Rodrigo Martínez-Abarca Michelle Abstein Frederik Schenk David Hodell Philipp Hoelzmann Mark Brenner Steffen Kutterolf Sergio Cohuo Laura Macario-González Mona Stockhecke Jason Curtis Flavio S. Anselmetti Daniel Ariztegui Thomas Guilderson Alexander Correa-Metrio Thorsten Bauersachs Liseth Pérez Antje Schwalb article RN10 Located at the triple junction of the Pacific, Eurasian and Sunda plates, the Island of Sulawesi in Indonesia is one of the most tectonically active places on Earth. This is highlighted by the recurrence of devastating earthquakes such as the 2018 Mw 7.5 earthquake that damaged the city of Palu and caused several thousand fatalities in central Sulawesi. The majority of large-magnitude earthquakes on Sulawesi are related to stress release along major strike-slip faults such as the Palu-Koro Fault and its southern extensions, the Matano and Lawanopo Faults. To date, information on the frequency and magnitude of past major events on these faults is limited to instrumental records and historical sources restricted to the last century, whereas information from natural archives is completely lacking. Lake-sediment records can fill this gap, but a detailed assessment of the various factors that influence the sensitivity of sediment successions to past earthquakes is required to evaluate their suitability. Lake Towuti, situated in Eastern Sulawesi, is known for its paleoclimate record and also promises to be a key site to generate a paleoseismology record for Sulawesi. The lake lies close to the highly active Matano and Lawanopo strike-slip faults and thereby is an ideal archive for past earthquakes that have occurred in the surrounding area. Here we combine high-resolution chirp seismic data with lithostratigraphic and petrophysical data of sediment piston cores to assess the recurrence of seismically generated mass-transport and turbidite deposits. Three major seismic-stratigraphic units are distinguished in the upper ∼10 m of the sediment succession and linked to differences in the frequency of mass-wasting during the past 60 kyrs. The evidence of a more turbidite-prone period between 12 and 40 ka is roughly coincident with a dry phase and associated lake-level lowstand during the last glacial period at Lake Towuti. Hence, we suggest that climate strongly influences the sensitivity of slopes to fail during seismic shaking in this tropical setting as a consequence of lowstand-forced sediment redeposition from the shelves onto the slopes and into the basins. As climate significantly impacts the sensitivity of the lacustrine sediments to record earthquake-related mass wasting deposits, we suggest that the frequency of mass-transport deposits can additionally be employed as a quantitative indicator for past changes in hydroclimate in these tropical settings. © 2023 The Authors Article 2023 English 02773791 10.1016/j.quascirev.2023.108015 Quaternary Science Reviews 305 Elsevier Ltd Catchments; Earth system models; Earthquakes; Fault slips; Sediments; Stratigraphy; Strike-slip faults; Tropics; Indonesia; Lake level changes; Lake sediments; Late Pleistocene; Mass transport deposit; Mass wasting; Paleoclimates; Paleoseismology; Seismic stratigraphy; Sulawesi/indonesia; Lakes https://www.scopus.com/inward/record.uri?eid=2-s2.0-85149434395&doi=10.1016%2fj.quascirev.2023.108015&partnerID=40&md5=999ae654fcd6bf6c1b23f876f358e095 Cited by: 0; All Open Access, Hybrid Gold Open Access Nicolas Tournier Stefano C. Fabbri Flavio S. Anselmetti Sri Yudawati Cahyarini Satria Bijaksana Nigel Wattrus James M. Russell Hendrik Vogel article sd-32-27-2023 2023 10.5194/sd-32-27-2023 Scientific Drilling 32 27-42 S. Schaller M. W. Buechi B. Schuster F. S. Anselmetti article Zou20231 Article 2023 10.19657/j.geoscience.1000-8527.2022.101 Geoscience 37 1 – 14 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85168809912&doi=10.19657%2fj.geoscience.1000-8527.2022.101&partnerID=40&md5=6d40d28c19ac3e47daa93872702a4ab6 Cited by: 5 Changchun Zou Chengshan Wang Cheng Peng Caowei Wu Yuan Gao article Zhang20231342 As the largest petroliferous basin in northeast (NE) China, Songliao Basin preserves continuous Cretaceous sedimentary-volcanic records, providing an excellent opportunity to recover the palaeo-environment. The Yingcheng Formation in the Songliao Basin contains ample gas reservoirs that attract widespread attention. Whereas the timing, petrogenesis and geodynamic mechanism of the volcanic rocks in the Yingcheng Formation are still controversial, which largely constrain our understanding of the formation and evolution of the Songliao Basin. Here, we present an integrated investigation of zircon U–Pb ages and Hf isotope, as well as whole-rock elements and Sr-Nd isotopes data for a suite of rhyolites of Yingcheng Formation from the SK2 Borehole of NE China. Zircon U–Pb age dating results of nine samples have yielded a concentrated age of ~110 Ma. These Yingcheng rhyolites are characterized by high SiO2 (66–78 wt%) and alkali (Na2O + K2O = 7.80–11.70 wt%) content, high 10000*Ga/Al (1.26–3.82, mostly >2.6) and FeOT/(FeOT + MgO) ratios (0.81–0.95), which show geochemical affinities with A-type rhyolites. They have relatively low Y/Nb (0.69–1.78, average 1.19) and Rb/Nb (1.58–6.52, average 4.34) ratios, suggesting that the Yingcheng volcanic samples belong to A1-type rhyolites which formed in an intraplate environment. These Yingcheng rhyolites show depleted Nd-Hf isotopic compositions (εNd(t) = 2.43–4.87 and zircon εHf(t) = 4.22–9.88) comparable with the Early Cretaceous A-type and I-type rhyolites in the Songliao Basin, suggesting that they were originated from a juvenile continental crust. They were most likely derived from the partial melting of anhydrous lower crust instead of differentiation of mantle-derived or mixing with alkaline basaltic magma, due to their low Mg# and absence of the coeval mafic rocks. Combined with the previous studies, A-type rhyolites in the Yingcheng Formation erupted lasting at least 10 Myr and were widely distributed in the rifts of the Songliao Basin. We propose that the Yingcheng rhyolites were most likely generated from the rollback of the Palaeo-Pacific Plate in the Early Cretaceous, thus highlighting the significance of the subduction of the Palaeo-Pacific Plate during the secular evolution of the Songliao Basin. © 2022 John Wiley & Sons Ltd. Article 2023 English 00721050 10.1002/gj.4662 Geological Journal 58 John Wiley and Sons Ltd 1342 – 1365 State Key Laboratory of Geological Processes and Mineral Resources and School of Earth Science and Resources, China University of Geosciences, Beijing, China; Guangxi Key Laboratory of Hidden Metallic Ore Deposits Exploration, Guilin University of Technology, Guilin, China; Shandong Provincial No. 4 Institute of Geological and Mineral Survey, Weifang, China 4 China; Songliao Basin; borehole; Cretaceous; geodynamics; hafnium; isotopic composition; neodymium isotope; petrogenesis; rhyolite; strontium isotope; uranium-lead dating; volcanic rock https://www.scopus.com/inward/record.uri?eid=2-s2.0-85144014016&doi=10.1002%2fgj.4662&partnerID=40&md5=656a564920fefec31b3f16b8252130b5 Cited by: 0 Zhao Zhang Feng Huang Jifeng Xu Xijun Liu Liying Zhang Man Zhang Xuli Yang Yunchuan Zeng Qian Liu article jeanneret_deciphering_2023 The Seve Nappe Complex is a subduction-related high-grade metamorphic unit that was emplaced onto the margin of Baltica during Caledonian orogenesis. In this paper, the tectonometamorphic evolution of the Lower Seve Nappe in the Scandinavian Caledonides was characterized with the help of the continuous Collisional Orogeny in the Scandinavian Caledonides (COSC-1) drill core, using a combination of various P–T estimation techniques based on garnet–quartz mineral pairs (quartz-in-garnet and Ti-in-quartz [QuiG–TiQ]), conventional thermobarometry and thermodynamic modelling of phase equilibria. This multi-method approach yields complementary results and delivers critical data to constrain a comprehensive pressure–temperature–deformation–time (P–T–D–t) evolutionary path for the metasedimentary rocks of the Lower Seve Nappe. In the garnetiferous metasedimentary rocks, quartz inclusions in garnet preserve the P–T conditions of three distinct garnet growth stages corresponding to three metamorphic stages Ms1 to Ms3, including prograde and peak metamorphic conditions. Ms1 and Ms2 stages were constrained via quartz inclusions in garnet core and mantle. They are relatively close in the P–T space and could be considered as one single continuous prograde event occurring at epidote–amphibolite facies conditions of 460–520°C and 0.6–0.85 GPa. The growth of the garnet outermost rim defines the Ms3 stage at amphibolite facies conditions of 590–610°C and 1.13–1.18 GPa and corresponds to the peak metamorphic conditions. The microstructural analysis shows that the finite ductile strain pattern of the Lower Seve Nappe results from the superposition of four deformation phases. The initial phase D1 is defined by the S1 foliation that is still preserved as a curved inclusion trail in the garnet core. The D2 phase initiated contemporaneously with garnet core growth and the development of muscovite–biotite–plagioclase S2 foliation. Garnet outermost rim growth marks the end of the prograde path and peak metamorphic conditions. This stage is overprinted by the D3 phase and Ms4 stage associated with the development of the main regional metamorphic and mylonitic fabric S3 associated with C′-type shear bands along the retrograde path. Ms4 stage, which was constrained using traditional thermobarometric techniques, corresponds to the chemical re-equilibration of the metasedimentary minerals and occurred under amphibolite facies conditions at 570–610°C and 0.78–1.00 GPa. The D3 phase is then generally weakly to strongly overprinted by later lower grade deformation D4 phase at greenschist facies conditions (Ms5). 40Ar/39Ar ages of syn-kinematic white mica and biotite indicate that the final stage of the thrusting of the Lower Seve Nappe and thus the timing of its emplacement onto the Offerdal Nappe occurred at c. 423 Ma. Collectively, these results are consistent with previous estimates of the timing and conditions of metamorphism derived from the Lower Seve Nappe especially in west-central Jämtland. However, application of QuiG–TiQ thermobarometry demonstrated that quartz inclusions in garnet can preserve different aspects of garnet growth, which are not accessible by traditional methods especially in complex terranes, and therefore provided new significant insights into the Lower Seve prograde evolution. 2023 en 1525-1314 10.1111/jmg.12693 Journal of Metamorphic Geology n/a n/a 40Ar/39Ar dating, Scandinavian Caledonides, P–T–D–t evolution, quartz-in-garnet, Ti-in-quartz thermobarometry https://onlinelibrary.wiley.com/doi/abs/10.1111/jmg.12693 \_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1111/jmg.12693 Pauline Jeanneret Iwona Klonowska Christopher Barnes Jarosław Majka Johanna Holmberg Mattia Gillio William Nachlas Matteo Alvaro Karolina Kośmińska Henning Lorenz Thomas Zack Anna Ladenberger Hemin Koyi article WOS:001022757300001 2023 10.1029/2022JB026130 JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH 128 6 electrical resistivity; elastic wave velocity; oceanic crust; crack; Oman drilling Project; IODP hole 1256D Y. Akamatsu K. Nagase N. Abe K. Okazaki K. Hatakeyama I. Katayama article Loukola-Ruskeeniemi2023 Black shales host critical raw materials such as graphite and cobalt and occur in the vicinity of many types of sulphide deposits. We report the procedure for country-wide mapping of graphite- and sulphide-rich rocks and the chemical and petrophysical data of 319 samples we selected from sulphide occurrences and mines in Finland. Even though black shales are rarely outcropped in glaciated and deeply weathered terrains, they can be traced with geophysical surveys. In the Precambrian of Finland, where the metamorphic grade varies from greenschist to granulite facies, systematic airborne geophysical surveys revealed stratigraphy-related, coupled magnetic and electrically conductive patterns. Electrical conductivity was related to the graphite and sulphide contents, producing continuous and bending electromagnetic anomaly patterns. The magnetic anomalies, if present, resulted from ferrimagnetic monoclinic pyrrhotite. The petrophysical properties of black shales varied in our sample set. The densities were mainly between 2700 and 3000 kg/m3, with the mean density ~ 2800 kg/m3, where the amount of graphite had a reducing effect on density whereas sulphides increased it. The average magnetic susceptibilities were about 6000·10−6 (SI), but they showed wide variation, depending on the abundance of ferrimagnetic monoclinic pyrrhotite. The electrical conductivity of black shales appeared to be positively related to the abundance of monoclinic pyrrhotite. Conductivity variation, 1–105 1/Ωm was based on laboratory determinations of apparent resistivities. We correlated an airborne magnetic and electromagnetic survey with petrophysical and chemical data from altogether 319 drill core samples containing >1 % graphitic C and >1 % S. The samples were selected during 2009–2011 from 102 drill cores all over Finland except for the Talvivaara–Outokumpu region, which was studied during previous projects. The black-shale-hosted Talvivaara Ni–Zn–Co–Cu deposit is currently being mined. The maximum graphite concentration in the country-wide sample set was 34.3 %, and the median value was 5.7 %, a lower value than reported from the Talvivaara black-shale-hosted sulphide deposit (7.6 %). S, Co, Cu, Fe and Ni concentrations were also lower in our sample set on average than in the Talvivaara ore. However, the maximum concentration in our sample set was 397 mg/kg for Co, 0.36 % for Cu, 40.8 % for Fe and 0.28 % for Ni. The developed black shale mapping procedure can be directly applied in other parts of the world in terrains with greenschist to granulite facies regional metamorphism. Information on basic petrophysical properties, i.e., density, magnetic and electric properties, are needed to explain geophysical anomalies. If the metamorphic grade is lower than greenschist facies and there is no graphite, sulphides will increase the electromagnetic properties. If ferrimagnetic pyrrhotite exists, susceptibility increases, as well as remanence. The black shale database covering the whole of Finland is used not only in exploration and bedrock mapping, but also in regional planning and for environmental risk analyses, because sulphide-rich black shales may cause acid rock drainage when exposed to weathering and the quality of surface water and groundwater may suffer from black shale bedrock and glacial till. The scale limitations given by airborne geophysics may request detailed studies in selected sites. © 2022 The Author(s) Article 2023 English 03756742 10.1016/j.gexplo.2022.107123 Journal of Geochemical Exploration 244 Elsevier B.V. Core drilling; Deposits; Electric conductivity; Geological surveys; Geophysics; Graphite; Infill drilling; Magnetic susceptibility; Oil shale; Sampling; Stratigraphy; Airborne geophysics; Black shales; Ferrimagnetics; Finland; Geophysical measurements; Greenschist; Monoclinics; Sample sets; Sulphide; Sulphide deposits; graphite; host rock; hydrocarbon exploration; hydrocarbon generation; petrography; shale; sulfide; Sulfur compounds https://www.scopus.com/inward/record.uri?eid=2-s2.0-85142126826&doi=10.1016%2fj.gexplo.2022.107123&partnerID=40&md5=e017ed42fa9292f6037cef0c108b99d4 Cited by: 1 Kirsti Loukola-Ruskeeniemi Eija Hyvönen Meri-Liisa Airo Jouni Lerssi Hilkka Arkimaa article Wu2023712 The Earth’s geologic record of Milankovitch cycles closely tracks Solar System solutions for the past 50 million years. Prior to 50 million years ago (Ma), however, the solutions lose accuracy rapidly due to chaotic behavior of the Solar System. Here we reconstruct a 10.173 million year-long record from 82.358 Ma to 92.531 Ma of Earth’s orbital parameters from a continental lacustrine sequence in the Songliao Basin, China, constrained by four in situ high-resolution radioisotopic U-Pb ages and magnetic reversal stratigraphy. Analysis of thorium and ostracode shell abundance records from the Songliao Basin reveal evidence for two chaotic secular resonance transitions in the orbital motions of Earth and Mars from 85.2 Ma to 91.55 Ma. The evidence validates similar observations in western North American marine stratigraphy. A unique phasing between the observed orbital eccentricity and obliquity modulations may explain the anoxic events that occurred in both marine and continental environments during this time. Taken together, the continental and marine stratigraphic evidence demonstrates a strong global reach of Late Cretaceous Milankovitch cycles, and provides an important constraint on Solar System chaoticity and the calculation of accurate orbital solutions prior to 50 Ma. © 2022 Geological Society of America Article 2023 English 00167606 10.1130/B36340.1 Bulletin of the Geological Society of America 135 Geological Society of America 712 – 724 3-4 China; Songliao Basin; Binary alloys; Earth (planet); Lead alloys; Orbits; Uranium alloys; Chaotic behaviour; High resolution; Lacustrine sequence; Late cretaceous; Magnetic reversal; Milankovitch cycle; Orbital parameters; Songliao basin; System solution; U-Pb ages; age determination; chaotic dynamics; Cretaceous; Earth; Mars; reconstruction; solar cycle; solar system; stratigraphy; uranium-lead dating; Stratigraphy https://www.scopus.com/inward/record.uri?eid=2-s2.0-85137554418&doi=10.1130%2fB36340.1&partnerID=40&md5=e9dc03cdd9b5afe9fd86adc84c82ad85 Cited by: 17; All Open Access, Green Open Access Huaichun Wu Linda A. Hinnov Shihong Zhang Ganqing Jiang Tianshui Yang Haiyan Li Dangpeng Xi Xiaojuan Ma Chengshan Wang article magson2023constraints 2023 Contributions to Mineralogy and Petrology 178 Springer 14 3 Justine Magson Frederick Roelofse Grant Bybee Robert Bolhar article Jurikova2023 Well-known for their geological and natural singularity, the Dead Sea brines evolved from a marine ingression of the Mediterranean during the Pliocene. Dead Sea brines are currently almost ten times more concentrated than seawater and have a unique chemical composition with high boron isotope values (δ11Bbrine = ∼57‰). However, little is known on how these values were attained and their underlaying driving processes. Here we use boron isotopes (δ11B) combined with B/Ca and B/Li of lacustrine authigenic aragonites from the deep basin drill-core ICDP 5017-1, and Ein Gedi and Masada profiles to reconstruct past brine conditions. Comparing reconstructed δ11Bbrine from two key periods of contrasting hydro-climatic regimes we find that the brines of the late Holocene Dead Sea were enriched in 11B (δ11Bbrine = ∼60‰) relative to its glacial precursor Lake Lisan (∼57‰). With the aid of boron cycle modelling, we quantify the main boron fluxes in the basin. We show that the post-glacial δ11Bbrine enrichment is best explained by overall reduction of freshwater inflow to the lake and coeval increase in 10B sink through boron co-precipitation in evaporitic deposits and boron loss in atmospheric water vapour, consistent with the onset of warmer and drier climate in the Eastern Mediterranean during the Holocene. On geological time scales, adsorption of 10B on clastic sediments has acted as an important 10B sink and can explain the evolution of the high δ11Bbrine values. © 2023 The Author(s) Article 2023 10.1016/j.epsl.2023.118403 Earth and Planetary Science Letters 622 Elsevier B.V. Budget control; Glacial geology; Infill drilling; Isotopes; Lakes; Seawater; Authigenic; Boron cycle; Boron isotope budget; Boron isotopes; Lacustrine authigenic aragonite; Pleistocene; Pleistocene lake lisan; Pliocene; Pliocene sedom lagoon; Seawater evolution; aragonite; authigenic mineral; boron; brine; concentration (composition); geochemistry; lacustrine environment; seawater; Boron https://www.scopus.com/inward/record.uri?eid=2-s2.0-85172727894&doi=10.1016%2fj.epsl.2023.118403&partnerID=40&md5=2fef2ad527e726ff88ffc30bcf0b7f84 Cited by: 4; All Open Access, Green Open Access, Hybrid Gold Open Access Hana Jurikova Simon J. Ring Michael J. Henehan Ina Neugebauer Birgit Schröder Daniela Müller Markus J. Schwab Rik Tjallingii Achim Brauer Cécile Blanchet article Li2023164 Article 2023 10.1016/j.gr.2023.03.016 Gondwana Research 119 164 – 171 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85151832947&doi=10.1016%2fj.gr.2023.03.016&partnerID=40&md5=6a067844bded85d332f4a19e01b5d719 Cited by: 5 Ming-Rui Li Rui Gao Jian-Bo Zhou Simon A Wilde He-Sheng Hou Xiao-Fan Deng article Haberland2023 We apply a transdimensional, hierarchical Markov chain Monte Carlo sampling algorithm (McMC) for 2-D cross-hole travel-time tomography in transversely isotropic media with vertical symmetry axis. The McMC approach has several advantages compared to classical inversion approaches: It is a global search, the high number of tested models allows the statistical analysis including the calculation of a reference model as well as uncertainty estimation, no initial models or regularization parameters are needed, the amount of data noise is automatically determined, and the model parametrization is data dependent and self-adjusting. For the forward solution a FD Fast Marching method utilizing second-order Godunov schemes is used. The performance of the approach is first tested on synthetic datasets to evaluate the potential and possible limitation to recover anisotropic models. We have shown that the recovery of models described by 2 anisotropic parameters (Thomsen parameters) and the vertical velocity is possible for observation scenarios with good distribution of sources and receivers. For more realistic observational geometries (i.e. cross-hole experiments), the recovery of the 3 parameters is limited, but still possible for example for the elliptical anisotropic case (ε = δ) or regarding the horizontal velocity. Finally we applied the McMC approach to a well-studied real cross-hole data set from the MALLIK 2002 research program and compared the results with previous conventional inversions. © 2022 2023 English 09269851 10.1016/j.jappgeo.2022.104917 Journal of Applied Geophysics 209 Elsevier B.V. Helmholtz Centre Potsdam GFZ German Research Centre for Geosciences, Potsdam, Germany; University of Helsinki, Helsinki, Finland Gas hydrates; Markov processes; Monte Carlo methods; Recovery; Seismology; Uncertainty analysis, Algorithm approaches; Bayesian; Cross hole; Finite difference; Markov chain monte carlo samplings; Monte carlo; Monte carlo sampling algorithms; Seismic; Transversal isotropy; Transversely isotropic medias, Anisotropy, algorithm; Bayesian analysis; data inversion; data set; finite difference method; gas hydrate; Markov chain; model test; Monte Carlo analysis; seismic tomography; seismic velocity; seismic wave; transverse isotropy; travel time https://www.scopus.com/inward/record.uri?eid=2-s2.0-85145773441&doi=10.1016%2fj.jappgeo.2022.104917&partnerID=40&md5=bd4779a5a71010167f3075da54d14613 cited By 0 C. Haberland T. Ryberg M. Riedel K. Bauer article WOS:001177567400001 2023 10.7185/geochemlet.2339 GEOCHEMICAL PERSPECTIVES LETTERS 28 20-26 A. Vuillemin M. Morlock A. Paskin L. G. Benning C. Henny J. Kallmeyer J. M. Russell H. Vogel article WOS:001136279200005 2023 10.1038/s41598-023-47439-4 SCIENTIFIC REPORTS 13 1 Giovanna Montesano Concetta Rispoli Paola Petrosino Marie D. Jackson Tobias B. Weisenberger Magnus T. Gudmundsson Piergiulio Cappelletti article Yin2023205 Lithology identification is an important task in oil and gas exploration. In recent years, machine learning methods have become a powerful tool for intelligent lithology identification. To address the redundancy of conventional logging data and unbalanced distribution among formation lithology classes due to the complexity of depositional environment and inhomogeneity of subsurface space, this paper investigates the affiliation-weighted one-to-one support vector machine (WOVOSVM) lithology identification method based on geochemical logging data. This method uses geochemical logging data, which can directly reflect the formation lithology information, as input, and achieves intelligent and accurate lithology classification under the calculation of WOVOSVM. In this study, Shahezi Formation of Songke 2 Well in Songliao Basin, China is taken as the experimental object, and two data sets with different distribution characteristics are selected as the input. Use WOVOSVM, Adaboost, random forest (RF) and traditional support vector machine (SVM) to identify lithology, and compare and analyze the results. The results are as follows: (1) Accuracy metrics of most of the four classification models were above 60%, indicating the geochemical logging data can effectively reflect the formation lithology information, which is a reliable indicator for the intelligent identification of logging lithology. (2) When the data set has a strong imbalance, the lithology recognition performance of WOVOSVM is better than other methods, the average value of accuracy metrics is more than 72%, F1 value is 8.77% to 14.56% higher than other models, especially in the small sample lithology category recognition, 70% of the samples are correctly classified. © 2023, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature. Article 2023 English 18650473 10.1007/s12145-022-00932-2 Earth Science Informatics 16 Springer Science and Business Media Deutschland GmbH 205 – 220 1 China; Songliao Basin; geochemical method; identification method; lithology; logging (geophysics); machine learning; support vector machine; weight https://www.scopus.com/inward/record.uri?eid=2-s2.0-85146039359&doi=10.1007%2fs12145-022-00932-2&partnerID=40&md5=c75291f59ddf2f144432b80382888411 Cited by: 2 Shitao Yin Xiaochun Lin Yongjian Huang Zhifeng Zhang Xiang Li article Vuillemin2023504 Ancient iron formations hold important records of environmental conditions during the Precambrian eons. Reconstructions of past oceanic systems require investigation of modern ferruginous analogs to disentangle water column and diagenetic signals recorded in iron-bearing minerals. We analyzed oxygen, iron, and carbon isotopes in siderite, a ferrous carbonate phase commonly used as an environmental proxy, from a 100-m-long record spanning a 1 Ma depositional history in ferruginous Lake Towuti, Indonesia. Combining bulk sediment and pore water geochemistry, we traced processes controlling siderite isotope signatures. We show that siderite oxygen isotope compositions (δ18O) reflect in-lake hydrological and depositional conditions. Low iron isotope values (δ56Fe) record water column oxygenation events over geological timescales, with minor diagenetic partitioning of Fe isotopes by microbial iron reduction after deposition. The carbon isotope compositions (δ13C) reflect the incorporation of biogenic HCO3 –, which is consistent with sediment organic matter remineralization lasting over ca. 200 ka after burial. Positive δ13C excursions indicate an increased production of biogenic methane that escaped the sediment during low lake levels. Diffusion across the sediment–water interface during initial formation of siderites tends to align the isotope signatures of bottom waters to those of pore waters. As microbial reduction of ferric iron and oxidation of organic matter proceed and saturate pore water conditions with respect to siderite, overgrowth on nuclei partially mutes the environmental signal inherited from past bottom waters over ca. 1 Ma. Because high depositional fluxes of ferric iron and organic matter in early oceans would have promoted similar microbial processes in ferruginous deposits prior to lithification, the environmental record contained in siderite grains can successively integrate depositional and early diagenetic signals over short geological timescales. © 2022 Geological Society of America Article 2023 English 00167606 10.1130/B36211.1 Bulletin of the Geological Society of America 135 Geological Society of America 504 – 522 1-2 Greater Sunda Islands; Lake Towuti; Malili Lakes; South Sulawesi; Sulawesi; Sunda Isles; Biogeochemistry; Deposition; Geology; Iron; Iron ores; Isotopes; Organic compounds; Oxygen; Sediments; Water; Biogenics; Bottom water; Diagenetics; Geological timescales; Iron isotopes; Isotope record; Isotope signatures; Pore waters; Water columns; δ13C; carbon isotope; depositional environment; iron; isotopic composition; oxygen; oxygenation; Precambrian; sediment chemistry; sediment-water interface; siderite; Lakes https://www.scopus.com/inward/record.uri?eid=2-s2.0-85143396496&doi=10.1130%2fB36211.1&partnerID=40&md5=8445726b48462a7e05fb31da2b295465 Cited by: 1; All Open Access, Green Open Access Aurèle Vuillemin Christoph Mayr Jan A. Schuessler André Friese Kohen W. Bauer Andreas Lücke Verena B. Heuer Clemens Glombitza Cynthia Henny Friedhelm Blanckenburg James M. Russell Satria Bijaksana Hendrik Vogel Sean A. Crowe Jens Kallmeyer article Schiferl2023 Article 2023 10.1038/s41467-023-43231-0 Nature Communications 14 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85176766328&doi=10.1038%2fs41467-023-43231-0&partnerID=40&md5=d77b9f59528c896f87a1cb8772663a73 Cited by: 7; All Open Access, Gold Open Access, Green Open Access J. Schiferl M. Kingston C.M. Åkesson B.G. Valencia A. Rozas-Davila D. McGee A. Woods C.Y. Chen R.G. Hatfield D.T. Rodbell M.B. Abbott M.B. Bush article WOS:000988166900005 2023 10.1093/gji/ggad182 GEOPHYSICAL JOURNAL INTERNATIONAL 234 1985-1998 3 Europe; Controlled source seismology; Seismic tomography; Continental tectonics: compressional; Crustal structure Trond Ryberg Christian Haberland Britta Wawerzinek Manfred Stiller Klaus Bauer Alberto Zanetti Luca Ziberna Gyoergy Hetenyi Othmar Müntener Michael M. Weber Charlotte M. Krawczyk article Qin2024168 Article 2023 10.19826/j.cnki.1009-3850.2023.08010 Sedimentary Geology and Tethyan Geology L. Luo M. Yu Q. Li Z. Wu Y. Huang article Liu2023 Article 2023 10.3390/min13010005 Minerals 13 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85146670146&doi=10.3390%2fmin13010005&partnerID=40&md5=cac2c6be9db96a26b4d65e4915bc80e3 Cited by: 4; All Open Access, Gold Open Access Zhenwu Liu Yuke Liu Xuejia Du Dan Lyu Huaichun Wu Huajian Wang article Qin2024168 Article 2023 10.11928/j.issn.1001-7410.2023.06.06 Quaternary Sciences 43 1573-1583 6 X. Ma S. Li R. Chu Q. Fang M. Shi H. Wu article Woith2023 Mofettes are gas emission sites where high concentrations of CO2 ascend through conduits from as deep as the mantle to the Earth’s surface and as such provide direct windows to processes at depth. The Hartoušov mofette, located at the western margin of the Eger Graben, is a key site to study interactions between fluids and swarm earthquakes. The mofette field (10 mofettes within an area of 100 m × 500 m and three wells of 28, 108, and 239 m depth) is characterized by high CO2 emission rates (up to 100 t/d) and helium signatures with (3He/4He)c up to 5.8 Ra, indicating mantle origin. We compiled geological, geophysical, geochemical, and isotopic data to describe the mofette system. Fluids in the Cheb basin are mixtures between shallow groundwater and brine (>40 g/L at a depth of 235 m) located at the deepest parts of the basin fillings. Overpressured CO2-rich mineral waters are trapped below the mudstones and clays of the sealing Cypris formation. Drilling through this sealing layer led to blow-outs in different compartments of the basin. Pressure transients were observed related to natural disturbances as well as human activities. External (rain) and internal (earthquakes) events can cause pressure transients in the fluid system within hours or several days, lasting from days to years and leading to changes in gas flux rates. The 2014 earthquake swarm triggered an estimated excess release of 175,000 tons of CO2 during the following four years. Pressure oscillations were observed at a wellhead lasting 24 h with increasing amplitudes (from 10 to 40 kPa) and increasing frequencies reaching five cycles per hour. These oscillations are described for the first time as a potential natural analog to a two-phase pipe–relief valve system known from industrial applications. © 2022 by the authors. Article 2023 English 20763263 10.3390/geosciences13010002 Geosciences (Switzerland) 13 MDPI 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85146749742&doi=10.3390%2fgeosciences13010002&partnerID=40&md5=44c99376ec52eefb4b9cb40f3691b295 Cited by: 0; All Open Access, Gold Open Access, Green Open Access Heiko Woith Josef Vlček Tomáš Vylita Torsten Dahm Tomáš Fischer Kyriaki Daskalopoulou Martin Zimmer Samuel Niedermann Jessica A. Stammeier Veronika Turjaková Martin Lanzendörfer article WOS:000927333300001 2023 10.1016/j.tecto.2023.229725 TECTONOPHYSICS 848 Fault zone; Downhole geophysical logs; Recurrent earthquakes; Scientific drilling; Koyna; India Nagaraju Podugu Deepjyoti Goswami Vyasulu V. Akkiraju Sukanta Roy article WOS:001053792900001 2023 10.1016/j.epsl.2023.118189 EARTH AND PLANETARY SCIENCE LETTERS 614 rifting; East Africa; Afar Stratoid Series; magmatism Tyrone O. Rooney Eric L. Brown Ian D. Bastow J. Ramón Arrowsmith Christopher J. Campisano article Jia2023 Article 2023 10.3389/fmicb.2023.1105259 Frontiers in Microbiology 14 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85161200278&doi=10.3389%2ffmicb.2023.1105259&partnerID=40&md5=94b72dda4a22c5ca095d81e00ac5436b Cited by: 6; All Open Access, Gold Open Access, Green Open Access Zeyu Jia Daniel Lipus Oliver Burckhardt Robert Bussert Megan Sondermann Alexander Bartholomäus Dirk Wagner Jens Kallmeyer conference Eichelberger20232868 Conference paper 2023 Transactions - Geothermal Resources Council 47 2868 – 2882 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85182023916&partnerID=40&md5=50dda0630f0b6adec23abb03648c9245 Cited by: 0 John Eichelberger Yan Lavallee Anette Mortensen Paolo Papale Freysteinn Sigmundsson article Jin2023 Owing to their cost-effectiveness, environmental friendliness, and high-efficiency, passive seismic methods are widely used in geophysical exploration. However, field passive seismic data suffer from low signal-to-noise ratio, as well as the fact that different types of seismic waves are naturally mixed together, which can affect the accuracy of subsurface imaging results and the subsequent geological interpretation. In this paper, we demonstrate that these problems can be addressed and present a case study on passive seismic detection in sedimentary basin areas adjacent to Well Songke-2 in Songliao Basin. To obtain accurate and reliable imaging results of the sedimentary strata, a detailed practical scheme is proposed, where fundamental and higher mode surface wave dispersion curves are inverted for obtaining the near-surface S-wave velocity profile, and the body wave component of ambient noise is utilized to retrieve the reflection wavefield information. The obtained profiles from surface wave inversion and reflection wavefield retrieval illustrate similar underground structures. The marker boundaries T2 (1.5 s) and T4 (2.1 s) are well demonstrated, and a low velocity stratum (0.4 s) is detected at a shallow depth of around 400–600 m. Further, the results are highly consistent with the data obtained from borehole logging of Well Songke-2 and the deep reflection seismic profile adjacent to this area, which indicates that the surface wave and body wave in passive seismic data can be utilized together to contribute to a detailed and accurate subsurface imaging and interpretation. Overall, this study investigated and validated the reliability and accuracy of the combination use of passive seismic methods for geological structure exploration, which can further boost their applications for geological interpretation in sedimentary basin areas. © 2022 Elsevier B.V. Article 2023 English 09269851 10.1016/j.jappgeo.2022.104898 Journal of Applied Geophysics 208 Elsevier B.V. China; Songliao Basin; Acoustic noise; Cost effectiveness; Sedimentology; Seismic prospecting; Seismic response; Shear waves; Signal to noise ratio; Surface waves; Underground structures; Wave energy conversion; Wave propagation; Ambient noise; Ambient noise seismic interferometry; Geological interpretation; High-mode surface wave inversion; Higher mode; Sedimentary basin; Sedimentary basin geological interpretation; Seismic interferometries; Songliao basin; Surface wave inversion; Well songke-2; ambient noise; sedimentary basin; seismic reflection; seismic wave; surface wave; wave field; Seismic waves https://www.scopus.com/inward/record.uri?eid=2-s2.0-85144053113&doi=10.1016%2fj.jappgeo.2022.104898&partnerID=40&md5=c74e899b8a9694b8e580f2b70e29a136 Cited by: 0 Zhong-Yuan Jin He-Sheng Hou Wei Fu Pan Zhang Dong-Zhao An Yong Hu article WOS:000915946900001 The nitrogen isotopic composition of organic matter is controlled by metabolic activity and redox speciation and has therefore largely been used to uncover the early evolution of life and ocean oxygenation. Specifically, positive delta N-15 values found in well-preserved sedimentary rocks are often interpreted as reflecting the stability of a nitrate pool sustained by water column partial oxygenation. This study adds much-needed data to the sparse Paleoarchean record, providing carbon and nitrogen concentrations and isotopic compositions for more than fifty samples from the 3.4 Ga Buck Reef Chert sedimentary deposit (BRC, Barberton Greenstone Belt). In the overall anoxic and ferruginous conditions of the BRC depositional environment, these samples yield positive delta N-15 values up to +6.1% . We argue that without a stable pool of nitrates, these values are best explained by non-quantitative oxidation of ammonium via the Feammox pathway, a metabolic co-cycling between iron and nitrogen through the oxidation of ammonium in the presence of iron oxides. Our data contribute to the understanding of how the nitrogen cycle operated under reducing, anoxic, and ferruginous conditions, which are relevant to most of the Archean. Most importantly, they invite to carefully consider the meaning of positive delta N-15 signatures in Archean sediments. Article 2023 10.1111/gbi.12540 GEOBIOLOGY 21 WILEY

111 RIVER ST, HOBOKEN 07030-5774, NJ USA

277-289 Pellerin, A (Corresponding Author), Univ Bourgogne Franche Comte, CNRS, Lab Biogeosci, UMR 6282, Dijon, France. Pellerin, Alice; Thomazo, Christophe; Vennin, Emmanuelle, Univ Bourgogne Franche Comte, CNRS, Lab Biogeosci, UMR 6282, Dijon, France. Thomazo, Christophe, Inst Univ France IUF, Paris, France. Ader, Magali, Univ Paris Cite, CNRS, Inst Phys Globe Paris, Paris, France. Marin-Carbonne, Johanna; Alleon, Julien, Univ Lausanne, Inst Sci Terre, Lausanne, Switzerland. Alleon, Julien, Univ Lyon, Univ Lyon 1, ENS Lyon, CNRS,LGL TPE, Lyon, France. Hofmann, Axel, Univ Johannesburg, Dept Geol, Johannesburg, South Africa. 3 ammonium oxidation; biogeochemistry; Buck Reef Chert; Feammox; ferruginous ocean; nitrogen isotopes; Paleoarchean Alice Pellerin Christophe Thomazo Magali Ader Johanna Marin-Carbonne Julien Alleon Emmanuelle Vennin Axel Hofmann article Han2023 The maturity of sedimentary organic matter is a key parameter for evaluating oil and gas resources. Existing maturity indicators have different evaluation principles and application scopes. This study investigated samples of high to overmature lacustrine source rocks (Ro = 1.33%–4.24%) from the deep Shahezi formation in the Songliao basin, including the zone of catagenesis and metagenesis. Various methods, including vitrinite reflectance, Tmax, laser Raman spectroscopy, and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) were used to evaluate the samples' maturity. Through laser Raman analysis of representative samples from the Shahezi formation, most laser Raman parameters showed an inflection point or reversal when the thermal evolution of deep source rocks in the Shahezi formation reaches a certain stage. The variation trend of some Raman parameters and Ro has strong regularity (1.33% < Ro < 3.52%). Based on FT-ICR MS, this research analyzed the relative content and molecular composition of polycyclic and heterocyclic aromatic compounds in soluble organic matter of lake source rock samples and comparison samples (marine shale). Quantitative maturity evaluation of organic matter was performed by converting the signal intensity of each compound. The fitting results of maturity parameter based on FT-ICR MS and Tmax indicated that the maturity parameter of the samples have high coefficient of correlations with maturity in the vitrinite reflectance (Ro) range of 1.33%–2.5% and the Tmax range of 420 °C–600 °C. The maturity parameter values decreased as Ro exceeded 2.5% and Tmax exceeded 600 °C. These findings are attributed to the thermal stability of organic compounds and the formation of pyrobitumen and graphite. The parameters of laser Raman spectroscopy also confirmed the growth of aromatic rings reflected by the maturity parameters of FT-ICR MS. These two methods revealed the structural changes of organic matter in the thermal evolution process from multiple perspectives and provided insights for the maturity evaluation of deep source rocks. © 2022 Article 2023 English 01665162 10.1016/j.coal.2022.104153 International Journal of Coal Geology 265 Elsevier B.V. China; Songliao Basin; Aromatic compounds; Energy resources; Mass spectrometry; Organic lasers; Petroleum deposits; Raman spectroscopy; Reflection; Fourier transform ion cyclotron resonance mass spectrometry; Fourier-transform ion cyclotron resonance mass spectrometry; Laser Raman; Laser Raman spectroscopy; Maturity parameters; Raman parameters; Shahezi formations; Songliao basin; Source rocks; Vitrinite reflectance; Fourier transform; hydrocarbon resource; lithostratigraphy; mass spectrometry; organic compound; organic matter; Raman spectroscopy; source rock; vitrinite reflectance; Thermodynamic stability https://www.scopus.com/inward/record.uri?eid=2-s2.0-85143344719&doi=10.1016%2fj.coal.2022.104153&partnerID=40&md5=b1c4d6ce7a967201a1968937ed2599f1 Cited by: 2 Shuangbiao Han Linfeng Xie Xin Du Chaohan Xiang Jie Huang Zhiyuan Tang Chengshan Wang Brian Horsfield Nicolaj Mahlstedt article sd-32-1-2023 2023 10.5194/sd-32-1-2023 Scientific Drilling 32 1--25 S. P. Hesselbo A. Al-Suwaidi S. J. Baker G. Ballabio C. M. Belcher A. Bond I. Boomer R. Bos C. J. Bjerrum K. Bogus R. Boyle J. V. Browning A. R. Butcher D. J. Condon P. Copestake S. Daines C. Dalby M. Damaschke S. E. Damborenea J.-F. Deconinck A. J. Dickson I. M. Fendley C. P. Fox A. Fraguas J. Frieling T. A. Gibson T. He K. Hickey L. A. Hinnov T. P. Hollaar C. Huang A. J. L. Hudson H. C. Jenkyns E. Idiz M. Jiang W. Krijgsman C. Korte M. J. Leng T. M. Lenton K. Leu C. T. S. Little C. MacNiocaill M. O. Mance\~nido T. A. Mather E. Mattioli K. G. Miller R. J. Newton K. N. Page J. P\'alfy G. Pie\'nkowski R. J. Porter S. W. Poulton A. C. Riccardi J. B. Riding A. Roper M. Ruhl R. L. Silva M. S. Storm G. Suan D. Szűcs N. Thibault A. Uchman J. N. Stanley C. V. Ullmann B. Schootbrugge M. L. Vickers S. Wadas J. H. Whiteside P. B. Wignall T. Wonik W. Xu C. Zeeden K. Zhao article WOS:000930327800001 2023 10.1111/jmg.12713 JOURNAL OF METAMORPHIC GEOLOGY 41 5 epidote; lower oceanic crust; olivine gabbro; Oman ophiolite; prehnite; serpentinization Toshio Nozaka Yamato Tateishi article WOS:001126644000001 2023 10.1111/pala.12684 PALAEONTOLOGY 66 Ginkgo; epidermal cell; micro-character; machine learning; palaeoclimate parameter Li Zhang Yongdong Wang Micha Ruhl Yuanyuan Xu Yanbin Zhu Pengcheng An Hongyu Chen Defei Yan article Nuppunen-Puputti2023 Microbial life in the deep subsurface occupies rock surfaces as attached communities and biofilms. Previously, epilithic Fennoscandian deep subsurface bacterial communities were shown to host genetic potential, especially for heterotrophy and sulfur cycling. Acetate, methane, and methanol link multiple biogeochemical pathways and thus represent an important carbon and energy source for microorganisms in the deep subsurface. In this study, we examined further how a short pulse of low-molecular-weight carbon compounds impacts the formation and structure of sessile microbial communities on mica schist surfaces over an incubation period of ∼3.5 years in microcosms containing deep subsurface groundwater from the depth of 500 m, from Outokumpu, Finland. The marker gene copy counts in the water and rock phases were estimated with qPCR, which showed that bacteria dominated the mica schist communities with a relatively high proportion of epilithic sulfate-reducing bacteria in all microcosms. The dominant bacterial phyla in the microcosms were Proteobacteria, Firmicutes, and Actinobacteria, whereas most fungal genera belonged to Ascomycota and Basidiomycota. Dissimilarities between planktic and sessile rock surface microbial communities were observed, and the supplied carbon substrates led to variations in the bacterial community composition. Copyright © 2023 Nuppunen-Puputti, Kietäväinen, Kukkonen and Bomberg. Article 2023 English 1664302X 10.3389/fmicb.2023.1054084 Frontiers in Microbiology 14 Frontiers Media S.A. acetic acid; carbon; ground water; methane; methanol; mica; RNA 16S; Actinobacteria; archaeon; Article; Ascomycetes; Basidiomycetes; bedrock; biofilm; Desulfobulbus; DNA extraction; Escherichia coli; Firmicutes; fungal community; gene sequence; microbial community; microbial diversity; microcosm; nonhuman; Proteobacteria; real time polymerase chain reaction https://www.scopus.com/inward/record.uri?eid=2-s2.0-85148343336&doi=10.3389%2ffmicb.2023.1054084&partnerID=40&md5=92b28b53725263693ec36163f2e707c3 Cited by: 0; All Open Access, Gold Open Access, Green Open Access Maija Nuppunen-Puputti Riikka Kietäväinen Ilmo Kukkonen Malin Bomberg article Peng2023 Article 2023 10.1016/j.palaeo.2023.111428 Palaeogeography, Palaeoclimatology, Palaeoecology 614 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85149679723&doi=10.1016%2fj.palaeo.2023.111428&partnerID=40&md5=36f4ec22c10146ac453d4d705439298d Cited by: 2 Cheng Peng Changchun Zou Huaichun Wu Shuxia Zhang Kouamelan Serge Kouamelan Chengshan Wang article NISSON202365 Geochemical and isotopic fluid signatures from a 2.9–3.2 km deep, 45–55 °C temperature, hypersaline brine from Moab Khotsong gold and uranium mine in the Witwatersrand Basin of South Africa were combined with radiolytic and water–rock isotopic exchange models to delineate brine evolution over geologic time, and to explore brine conditions for habitability. The Moab Khotsong brines were hypersaline (Ca-Na-Cl) with 215–246 g/L TDS, and Cl− concentrations up to 4 mol/L suggesting their position as a hypersaline end-member significantly more saline than any previously sampled Witwatersrand Basin fluids. The brines revealed low DIC (∼0.266–∼1.07 mmol/L) with high (∼8.49–∼23.6 mmol/L) DOC pools, and several reduced gaseous species (up to 46 % by volume H2) despite microoxic conditions (Eh = 135–161 mV). Alpha particle radiolysis of water to H2, H2O2, and O2 along with anhydrous-silicate-to-clay alteration reactions predicted 4 mol/L Cl− brine concentration and deuterium enrichment in the fracture waters over a period > 1.00 Ga, consistent with previously reported 40Ar noble gas-derived residence times of 1.20 Ga for this system. In addition, radiolytic production of 7–26 nmol/(L × yr) H2, 3–11 nmol/(L × yr) O2, and 1–8 nmol/(L × yr) H2O2 was predicted for 1–100μ g/g 238U dosage scenarios, supporting radiolysis as a significant source of H2 and oxidant species to deep brines over time that are available to a low biomass system (102–103 cells/mL). The host rock lithology was predominately Archaean quartzite, with minerals exposed on fracture surfaces that included calcite, pyrite, and chlorite. Signatures of δ18Ocalcite, δ13Ccalcite, Δ33Spyrite, δ34Spyrite and 87Sr/86Sr obtained from secondary ion mass spectrometry (SIMS) microanalyses suggest several discrete fluid events as the basin cooled from peak greenschist conditions to equilibrium with present-day brine temperatures. The brine physiochemistry, geochemistry, and cellular abundances were significantly different from those of a younger, shallower, low salinity dolomitic fluid in the same mine, and both were different from the mine service water. These results indicate the discovery of one of few long-isolated systems that supports subsurface brine formation via extended water–rock interaction, and an example of a subsurface brine system where abiotic geochemistry may support a low biomass microbial community. 2023 0016-7037 https://doi.org/10.1016/j.gca.2022.11.015 Geochimica et Cosmochimica Acta 340 65-84 Groundwater, Brine, Radiolysis, Isotope geochemistry, Deep biosphere https://www.sciencedirect.com/science/article/pii/S0016703722006226 D.M. Nisson T.L. Kieft H. Drake O. Warr B. Sherwood Lollar H. Ogasawara S.M. Perl B.M. Friefeld J. Castillo M.J. Whitehouse E. Kooijman T.C. Onstott article Guédron2023 Holocene climate in the high tropical Andes was characterized by both gradual and abrupt changes, which disrupted the hydrological cycle and impacted landscapes and societies. High-resolution paleoenvironmental records are essential to contextualize archaeological data and to evaluate the sociopolitical response of ancient societies to environmental variability. Middle-to-Late Holocene water levels in Lake Titicaca were reevaluated through a transfer function model based on measurements of organic carbon stable isotopes, combined with high-resolution profiles of other geochemical variables and paleoshoreline indicators. Our reconstruction indicates that following a prolonged low stand during the Middle Holocene (4000 to 2400 BCE), lake level rose rapidly ~15 m by 1800 BCE, and then increased another 3 to 6 m in a series of steps, attaining the highest values after ~1600 CE. The largest lake-level increases coincided with major sociopolitical changes reported by archaeologists. In particular, at the end of the Formative Period (500 CE), a major lake-level rise inundated large shoreline areas and forced populations to migrate to higher elevation, likely contributing to the emergence of the Tiwanaku culture. Copyright © 2023 the Author(s). Article 2023 10.1073/pnas.2215882120 Proceedings of the National Academy of Sciences of the United States of America 120 2 Climate; Lakes; Water; biological marker; organic carbon; water; Andes; archeology; Article; cultural anthropology; environmental parameters; geochemical analysis; geographic and geological phenomena; geographic elevation; Holocene; human; lake; lake basin; lake sediment; lake water level; Late Holocene; Middle Holocene; paleoecology; paleoeshoreline; politics; population migration; scientist; shoreline; social evolution; stable isotope labeling; chemistry; climate https://www.scopus.com/inward/record.uri?eid=2-s2.0-85145428330&doi=10.1073%2fpnas.2215882120&partnerID=40&md5=9d4e65969f07bbb692b2849031fe62dc Cited by: 0; All Open Access, Green Open Access, Hybrid Gold Open Access Stéphane Guédron Christophe Delaere Sherilyn C. Fritz Julie Tolu Pierre Sabatier Anne-Lise Devel Carlos Heredia Claire Vérin Eduardo Q. Alves Paul A. Baker article Zhang2023 SK-2 borehole in Songliao Basin provides unprecedented geological materials for investigating the Early Cretaceous continental paleoenvironment and paleoclimate in northeastern China. The lacustrine successions of the lower Shahezi (K1sh) Formation at the depth from 4,542 to 5,695 m was systematically studied using environmental magnetism and cyclostratigraphy in this study. Magnetic analysis reveals an inverse correlation between magnetic susceptibility (MS) and lithological ranks in fine clastic sediments, with the highest values in mudstones and the lowest in sandstones. The main magnetism carriers in the lower K1sh are pseudo-single-domain (PSD) and/or multi-domain (MD) magnetite with minor presence of hematite. MS was used to further explore the genesis of the environmental and climatic variations through cyclostratigraphic analysis. Sedimentary cycles of 113 m, 34 m, 13 m and 6 m can be identified in the power spectrum, which were interpreted as long and short eccentricity, obliquity, and precession cycles, demonstrating the impact of astronomical cyclicity on sedimentary rhythmicity. Floating astronomical time scale (FATS) of 4,090 kyr and 4,148 kyr were established by tuning the inferred long and short eccentricity cycles to the artificial 405-kyr and 105-kyr orbital eccentricity curves respectively. The estimated sediment accumulation rate around 28 cm/kyr confirms the rapid deposition process within the faulted lacustrine basin. Based on this study, the lake level oscillations in Songliao Basin are assumed to be shaped by long and short eccentricity, precession and semi-precession cycles during Early Cretaceous. This study also indicates that the sand-mudstone alternations deposition in K1sh is most likely driven by the seasonal discrepancies of summer insolation during semi-precession periods. Copyright © 2023 Zhang, Wu, Zhang, Yang, Li, Fang and Shi. Article 2023 English 22966463 10.3389/feart.2023.1077787 Frontiers in Earth Science 11 Frontiers Media S.A. China; Songliao Basin; Cretaceous; cyclostratigraphy; geomagnetism; hierarchical system; lacustrine deposit; Milankovitch cycle; paleoclimate; paleoenvironment https://www.scopus.com/inward/record.uri?eid=2-s2.0-85149664921&doi=10.3389%2ffeart.2023.1077787&partnerID=40&md5=e75a85b50849d25fc05b2926240241aa Cited by: 1; All Open Access, Gold Open Access Shujing Zhang Huaichun Wu Shihong Zhang Tianshui Yang Haiyan Li Qiang Fang Meinan Shi article Hollaar2023979 The Late Pliensbachian Event (LPE), in the Early Jurassic, is associated with a perturbation in the global carbon cycle (positive carbon isotope excursion (CIE) of ∼2‰), cooling of ∼5C, and the deposition of widespread regressive facies. Cooling during the late Pliensbachian has been linked to enhanced organic matter burial and/or disruption of thermohaline ocean circulation due to a sea level lowstand of at least regional extent. Orbital forcing had a strong influence on the Pliensbachian environments and recent studies show that the terrestrial realm and the marine realm in and around the Cardigan Bay Basin, UK, were strongly influenced by orbital climate forcing. In the present study we build on the previously published data for long eccentricity cycle E459±1 and extend the palaeoenvironmental record to include E458±1. We explore the environmental and depositional changes on orbital timescales for the Llanbedr (Mochras Farm) core during the onset of the LPE. Clay mineralogy, X-ray fluorescence (XRF) elemental analysis, isotope ratio mass spectrometry, and palynology are combined to resolve systematic changes in erosion, weathering, fire, grain size, and riverine influx. Our results indicate distinctively different environments before and after the onset of the LPE positive CIE and show increased physical erosion relative to chemical weathering. We also identify five swings in the climate, in tandem with the 405kyr eccentricity minima and maxima. Eccentricity maxima are linked to precessionally repeated occurrences of a semi-arid monsoonal climate with high fire activity and relatively coarser sediment from terrestrial runoff. In contrast, 405kyr minima in the Mochras core are linked to a more persistent, annually wet climate, low fire activity, and relatively finer-grained deposits across multiple precession cycles. The onset of the LPE positive CIE did not impact the expression of the 405kyr cycle in the proxy records; however, during the second pulse of heavier carbon (13C) enrichment, the clay minerals record a change from dominant chemical weathering to dominant physical erosion. © 2023 Teuntje P. Hollaar et al. Article 2023 10.5194/cp-19-979-2023 Climate of the Past 19 Copernicus Publications 979 – 997 5 Cardigan Bay; United Kingdom; Wales; carbon cycle; chemical weathering; climate forcing; environmental change; orbital forcing; organic matter; paleoenvironment; palynology; Pliensbachian; thermohaline circulation https://www.scopus.com/inward/record.uri?eid=2-s2.0-85160956356&doi=10.5194%2fcp-19-979-2023&partnerID=40&md5=fb54a3176859845c384a8a079b2eb9e6 Cited by: 5; All Open Access, Gold Open Access, Green Open Access Teuntje P. Hollaar Stephen P. Hesselbo Jean-François Deconinck Magret Damaschke Clemens V. Ullmann Mengjie Jiang Claire M. Belcher article Jiang2023 Article 2023 10.1029/2023GL103055 Geophysical Research Letters 50 8 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85158927924&doi=10.1029%2f2023GL103055&partnerID=40&md5=181e2d69dd15efe0791ff1b81a2cb2f2 Cited by: 9; All Open Access, Gold Open Access Guangzheng Jiang Yuntao Tian Qingtian Lv Mike Sandiford Yizuo Shi Changchun Zou Feng Ma Chenglong Deng Lijuan He Shengbiao Hu article Yang20231296 Based on the deep cores of Well Songke-2 (SK-2), uniaxial compression tests of deep rock from 8 different depths in the 4900–6830 m range were carried out, and deformation and failure characteristics were analyzed in detail. It was found that in the range of 4900–6830 m, the mechanical parameters of uniaxial compression tests of rocks changed nonlinearly with depth, and the strength was positively correlated with the hard mineral content. Comparing the rock failure of these samples with the 4500–7000 m core disc segment in SK-2, it was found that the failure of magmatic rock samples in both cases was smoother than that of sedimentary rock, indicating that deep magmatic rocks more easily released energy during the failure process. From depths of 4900–6000 m, prepeak characteristic stresses increased with increasing depth, while from depths of 6000–6830 m, they decreased with increasing depth. Fracture closure stress was used to characterize rock sampling damage at depths of 1000–6830 m, and it was found that sampling damage varied linearly with burial depth in sedimentary strata, while in igneous strata, sampling damage remained stable with increasing burial depth. © 2023, Central South University. Article 2023 English 20952899 10.1007/s11771-023-5310-z Journal of Central South University 30 Central South University of Technology 1296 – 1310 4 Minerals; Sedimentary rocks; Sedimentology; Burial depths; Characteristic stress; Deep rocks; Deformation and failures; Different depth; Magmatic rock; Mechanical behavior; Sampling damage; Uni-axial compression tests; Well songke-2; Compression testing https://www.scopus.com/inward/record.uri?eid=2-s2.0-85160213574&doi=10.1007%2fs11771-023-5310-z&partnerID=40&md5=7498e89445e9dcb0af433417e0feb1f2 Cited by: 0 Ming-qing Yang Jia-nan Li Ming-zhong Gao Ling Chen Cong Li Zhi-qiang He Zi-jie Wei He-ping Xie article mandende2023hyperspectral 2023 Journal of the Southern African Institute of Mining and Metallurgy 123 The Southern African Institute of Mining and Metallurgy 81--92 2 H Mandende C Ndou T Mothupi article Steinhoff20221191 Article 2022 10.1017/RDC.2022.34 Radiocarbon 64 1191 – 1207 5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85140070520&doi=10.1017%2fRDC.2022.34&partnerID=40&md5=45a26e518bdae10d6c6cbe0b28ec7e27 Cited by: 2; All Open Access, Hybrid Gold Open Access Christoph Steinhoff Nadine Pickarski Thomas Litt Irka Hajdas Caroline Welte Peter Wurst David Kühne Andreas Dolf Maximilian Germer Jens Kallmeyer article deGraaff2022293 This study presents petrographic and geochemical characterization of 46 pre-impact rocks and 32 impactites containing and/ or representing impact melt rock from the peak ring of the Chicxulub impact structure (Yucatán, Mexico). The aims were both to investigate the components that potentially contributed to the impact melt (i.e., the preimpact lithologies) and to better elucidate impact melt rock emplacement at Chicxulub. The impactites presented here are subdivided into two sample groups: the lower impact melt rock-bearing unit, which intrudes the peak ring at different intervals, and the upper impact melt rock unit, which overlies the peak ring. The geochemical characterization of five identified pre-impact lithologies (i.e., granitoid, dolerite, dacite, felsite, and limestone) was able to constrain the bulk geochemical composition of both impactite units. These pre-impact lithologies thus likely represent the main constituent lithologies that were involved in the formation of impact melt rock. In general, the composition of both impactite units can be explained by mixing of the primarily felsic and mafic lithologies, but with varying degrees of carbonate dilution. It is assumed that the two units were initially part of the same impact-produced melt, but discrete processes separated them during crater formation. The lower impact melt rock-bearing unit is interpreted to represent impact melt rock injected into the crystalline basement during the compression/excavation stage of cratering. These impact melt rock layers acted as delamination surfaces within the crystalline basement, accommodating its displacement during peak ring formation. This movement strongly comminuted the impact melt rock layers present in the peak ring structure. The composition of the upper impact melt rock unit was contingent on the entrainment of carbonate components and is interpreted to have stayed at the surface during crater development. Its formation was not finalized until the modification stage, when carbonate material would have reentered the crater. © 2022 Geological Society of Amer. All Rights Reserved. 2022 10.1130/B35795.1 Bulletin of the Geological Society of America 134 293-315 Analytical, Environmental & Geo-Chemistry Research Unit, Department of Chemistry, Vrije Universiteit Brussel, AMGC-WE-VUB, Pleinlaan 2, Brussels, 1050, Belgium; Laboratoire G-Time, Université Libre de Bruxelles, ULB, Avenue F.D. Roosevelt 50, Brussels, 1050, Belgium; Institute for Geophysics & Department of Geological Sciences, Jackson School of Geosciences, University of Texas at Austin, Austin, TX 78758, United States; Center for Planetary Systems Habitability, University of Texas at Austin, Austin, TX 78712, United States; Department of Lithospheric Research, University of Vienna, Althanstrasse 14, Vienna, A-1090, Austria; Natural History Museum, Burgring 7, Vienna, A-1010, Austria; Department of Earth Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1085, HV, Amsterdam, 1081, Netherlands 1-2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85125720004&doi=10.1130%2fB35795.1&partnerID=40&md5=afc34e8e75b06844aea68c953123480f cited By 10 S.J. Graaff P. Kaskes T. Déhais S. Goderis V. Debaille C.H. Ross S.P.S. Gulick J.-G. Feignon L. Ferrière C. Koeberl J. Smit N. Mattielli P. Claeys article hong2022new 2022 Journal of Geophysical Research: Solid Earth 127 Wiley Online Library e2022JB024379 7 Gilbert Hong Jessica Lynn Till Annika Greve Sang-Mook Lee Oman Drilling Project Phase 2 Science Party article Arz2022415 Book chapter 2022 10.1130/2022.2557(20) Special Paper of the Geological Society of America 557 415 – 448 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85143871178&doi=10.1130%2f2022.2557%2820%29&partnerID=40&md5=8f572b09c87918a4626fbc9f52079de2 Cited by: 9 José A. ARZ I. Arenillas J.M. Grajales-Nishimura C.L. Liesa A.R. Soria R. Rojas T. Calmus V. Gilabert article Li2022 The Mackenzie Delta (MD) is a permafrost-bearing region along the coasts of the Canadian Arctic which exhibits high sub-permafrost gas hydrate (GH) reserves. The GH occurring at the Mallik site in the MD is dominated by thermogenic methane (CH4), which migrated from deep conventional hydrocarbon reservoirs, very likely through the present fault systems. Therefore, it is assumed that fluid flow transports dissolved CH4 upward and out of the deeper overpressurized reservoirs via the existing polygonal fault system and then forms the GH accumulations in the Kugmallit–Mackenzie Bay Sequences. We investigate the feasibility of this mechanism with a thermo– hydraulic–chemical numerical model, representing a cross section of the Mallik site. We present the first simulations that consider permafrost formation and thawing, as well as the formation of GH accumulations sourced from the upward migrating CH4-rich formation fluid. The simulation results show that temperature distribution, as well as the thickness and base of the ice-bearing permafrost are consistent with corresponding field observations. The primary driver for the spatial GH distribution is the permeability of the host sediments. Thus, the hypothesis on GH formation by dissolved CH4 originating from deeper geological reservoirs is successfully validated. Furthermore, our results demonstrate that the permafrost has been substantially heated to 0.8–1.3 °C, triggered by the global temperature increase of about 0.44 °C and further enhanced by the Arctic Amplification effect at the Mallik site from the early 1970s to the mid-2000s. © 2022 by the authors. Licensee MDPI, Basel, Switzerland. 2022 English 19961073 10.3390/en15144986 Energies 15 MDPI GFZ German Research Centre for Geosciences, Potsdam, 14473, Germany; Institute of Geosciences, University of Potsdam, Potsdam, 14476, Germany; Institute of Chemistry, University of Potsdam, Potsdam, 14476, Germany 14 Flow of fluids; Gas hydrates; Hydration; Methane; Numerical models; Permafrost; Proven reserves, Canadian Arctic; CH 4; Conventional hydrocarbons; Dissolved CH; Fault; Fault system; Gas hydrates formation; Hydrate accumulations; Mallik; Thermogenic methane, Climate change https://www.scopus.com/inward/record.uri?eid=2-s2.0-85133769521&doi=10.3390%2fen15144986&partnerID=40&md5=52ccd192651a7a678ea2f1fd08041259 cited By 1 Z. Li E. Spangenberg J.M. Schicks T. Kempka article Zhang2022 The mechanisms of short-term (105–106 years) and high-magnitude (>20 m) sea-level oscillations have long been debated involving glacio- and aquifer-eustasy, largely owing to the sparse robust evidence for the presence and significance of aquifer-eustasy, and lack of knowledge about the hydrological dynamics behind it. Non-marine/continental greenhouse archives (e.g., lake level) and their temporal correlation to marine successions (e.g., sea level) could provide clues to aquifer-eustasy. The Songliao Basin (SLB) in Northeast China is one of the largest Mesozoic terrestrial inland basins and provides a terrestrial archive of nearly all Cretaceous successions. The greenhouse late Santonian–early Campanian lower Nenjiang Formation (K2n1+2), recovered from three boreholes in the SLB, provides a unique opportunity for validating and decoding aquifer-eustasy. Initially, the cyclostratigraphy of logging gamma ray (GR) and thorium (Th) series from three boreholes was implemented, which in conjunction with precise geochronological (U/Pb zircon) ages renewed the chronology framework of the SLB. Using the astronomically tuned GR and Th datasets, the lake level of the SLB, which was recovered from sedimentary noise modeling and presented as a proxy for the water table of the groundwater reservoir, showed a clear out-of-phase relationship with the coeval sea level, validating the aquifer-eustasy hypothesis. The lake level of SLB shows prominent ∼1.2 Myr cycles and a well-coupled relationship with sea level and obliquity modulation, indicating that orbital obliquity drove the lake level and modulated water exchange between ocean and continent during the Cretaceous greenhouse period. Strong precipitation events indicated by negative excursions of ostracod δ18O correlate well with high lake levels, high obliquity, and low sea level, suggesting that more moisture was precipitated into the high-latitude continents during obliquity modulation maxima, consequently recharging the aquifer and raising the lake level while drawing down the sea level and vice versa. The close correlation between the reported marine incursion layers and the lowstand of sea level casts a doubt on the marine incursion hypothesis in the SLB; thus, more work is needed to reconcile this paradox. Overall, this study provides the first robust geological evidence for aquifer-eustasy and decodes its role in Cretaceous short-term eustasy. © 2022 Elsevier B.V. Article 2022 English 0012821X 10.1016/j.epsl.2022.117800 Earth and Planetary Science Letters 596 Elsevier B.V. Boreholes; Gamma rays; Geochronology; Greenhouses; Groundwater resources; Lakes; Modulation; Reservoirs (water); Sea level; Zircon; Aquifer-eustasy; Cretaceous; Eustasy; Gamma-rays; Lake levels; Marine incursion; Nenjiang formation; Obliquity; The songliao basin; Aquifers https://www.scopus.com/inward/record.uri?eid=2-s2.0-85134320958&doi=10.1016%2fj.epsl.2022.117800&partnerID=40&md5=497e006cecc5322eba153e2b283b0ab0 Cited by: 7 Zhifeng Zhang Yongjian Huang Mingsong Li Xiang Li Pengcheng Ju Chengshan Wang article Lupien2022 Article 2022 10.1038/s41598-022-06826-z Scientific Reports 12 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85125336367&doi=10.1038%2fs41598-022-06826-z&partnerID=40&md5=f6b25b13ded84c28d1e06bcdeffddcb0 Cited by: 28; All Open Access, Gold Open Access, Green Open Access Rachel L. Lupien James M. Russell Emma J. Pearson Isla S. Castañeda Asfawossen Asrat Verena Foerster Henry F. Lamb Helen M. Roberts Frank Schäbitz Martin H. Trauth Catherine C. Beck Craig S. Feibel Andrew S. Cohen article Liu2022 In this study, we discuss the methods and results for the tectonolayer of a hydrocarbon basin using airborne gravity and magnetic data in the Qijia-Gulong area of the Songliao Basin. Using the latest airborne gravity and magnetic data combined with seismic and drilling data, we determined the density and magnetic measurement data of strata (rocks) in the study area. Next, density and structural stratifications were conducted. The structural sections of the strata-structure-magmatic rocks in the shallow, middle, and deep strata of the basin were determined, and a three-dimensional framework with multiple levels of the basin was constructed. Combining qualitative analysis and quantitative calculation, we explained the depths of the bottom of the Cenozoic layer, the bottom of the Upper Cretaceous layer, the bottom of the Mesozoic layer, and the top of the magnetic basement. We also determined the thicknesses of the Cenozoic layer, the Upper Cretaceous layer, the Upper Jurassic-Lower Cretaceous layer, and the Upper Paleozoic layer. These provide important achievements for the new petroliferous strata survey of regional Upper Paleozoic and Upper Jurassic-Lower Cretaceous strata. At the same time, it provides a new exploration method for studying are as with magmatic rocks and unclear deep seismic reflections. The results show that the new Upper Paleozoic strata (with a thickness of 0–9200 m) are mainly distributed in the central and eastern regions but absent in the western region. This yields significant differences in different regions of the study area. The thickness and depth of the Upper Jurassic-lower Cretaceous layer were different between the eastern and western regions; thicker and deeper in the middle eastern region but thinner and shallower in the western region. © 2022, The Editorial Department of APPLIED GEOPHYSICS. All rights reserved. 2022 English 16727975 10.1007/s11770-022-0970-2 Applied Geophysics Higher Education Press Limited Company China Aero Geophysical Survey and Remote Sensing Center for Nature Resources, 31 Xueyuan Road, Haidian District, Beijing, 100083, China; College of Geo-Exploration Science and Technology, Jilin University, Changchun, 130021, China; Oil and Gas Engineering Research Institute of Jilin Oilfield Company, Jilin Jilin, 138000, China https://www.scopus.com/inward/record.uri?eid=2-s2.0-85131597101&doi=10.1007%2fs11770-022-0970-2&partnerID=40&md5=0e43f709a812f1f1206f12886962fdeb cited By 2 Y.-X. Liu W.-Y. Li G.-Q. Ma A.-Q. Cao S. Gao N. Wang W.-F. Lu L.-J. Wang C. Yang article kelemen2022ongoing 2022 Authorea Preprints Authorea Peter B Kelemen James A Leong Juan Carlos Obeso Juerg Matter Eric T Ellison Alexis S Templeton Daniel B Nothaft Alireza Eslami Katy Evans Marguerite Godard others article Deocampo202242 Article 2022 10.1130/G49140.1 Geology 50 42 – 47 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85122596874&doi=10.1130%2fG49140.1&partnerID=40&md5=a7bca3beeb55a547588c81c789d911d5 Cited by: 5; All Open Access, Green Open Access D.M. Deocampo R.B. Owen T.K. Lowenstein R.W. Renaut N.M. Rabideaux A. Billingsley A. Cohen A.L. Deino M.J. Sier S. Luo C.-C. Shen D. Gebregiorgis C. Campisano A. Mbuthia article Li2022 The International Continental Scientific Drilling Project of Cretaceous Songliao Basin has recovered a complete Cretaceous terrestrial sedimentary record in northeastern China, providing a unique opportunity to understand the terrestrial climate change during the Cretaceous period. In this study, we present high-resolution geochemical records from Members 3 and 4 of the Quantou Formation in the SK-1 South borehole. The findings show that samples from Members 3 and 4 of the Quantou Formation originated from a source area of a homogeneous composition. Most of the samples were sediments that underwent the first round of weathering. The geochemical proxies (Th, CIA, CIW, τNa) and average value of the CIA proxy indicate that the strata have been subjected to moderate chemical weathering. The weathering intensity trend was divided into four evolutionary stages based on the CIA proxy: the steady lower part (1915–1878 m), the slowly rising lower and middle part (1878–1815 m), the middle and upper part (1815–1800 m) showing the highest values, and the gently fluctuating upper part (1800–1783 m). Precession, obliquity, and short-eccentricity signals were recognized in the proxies of Th, τNa, corrected CIA, and corrected CIW from Members 3 and 4 of the Quantou Formation, including about seven short-eccentricity cycle periods with a duration of ∼700 ka. The high peaks in short-eccentricity correspond to the high values of Th, corrected CIA, and corrected CIW proxies, and are consistent with the amplitudes of precession signals preserved in τNa during humid periods. During strong precession, the enhanced seasonal contrasts increased humidity, which intensified chemical weathering. The paleoclimatic pattern of interaction between the monsoon-like system and westerlies in the Cretaceous Songliao Basin may be the underlying interpretation that causes cyclic variation in the chemical weathering proxies in Members 3 and 4 of the Quantou Formation. © 2022 Elsevier B.V. Article 2022 English 09218181 10.1016/j.gloplacha.2022.103982 Global and Planetary Change 218 Elsevier B.V. China; Songliao Basin; Climate change; Geochemistry; Chemical weathering; Continental scientific drillings; Drilling projects; Late cretaceous; Orbital forcing; Paleoclimate change; Paleoclimatic pattern; Quantou formation; Sedimentary records; Songliao basin; chemical weathering; Cretaceous; orbital forcing; paleoclimate; seasonal variation; Weathering https://www.scopus.com/inward/record.uri?eid=2-s2.0-85141223954&doi=10.1016%2fj.gloplacha.2022.103982&partnerID=40&md5=49472791b4d84601740706b1a111f43f Cited by: 1 Xiang Li Yongjian Huang Zhifeng Zhang Chengshan Wang Tianshui Yang article WOS:000831563400008 Article 2022 10.1016/j.epsl.2022.117589 EARTH AND PLANETARY SCIENCE LETTERS 589 biomarker; C/N/S-stable isotopes; TEX86; primary productivity; paleosalinity; pigments Bettina Schaefer Lorenz Schwark Michael E. Böttcher Vann Smith Marco J. L. Coolen Kliti Grice article LeBer2022 A new set of physical property measurements was undertaken on 29 peak-ring samples from the IODP-ICDP Expedition 364. Among the studied lithologies, the dominant one recovered in the peak ring consists of shocked granitoid rocks (19 samples). Porosity measurements with two independent methods (triple weight and 14C-PMMA porosity mapping) concur and bring new observations on the intensity and distribution of fracturing and porosity in these shocked target rocks. Characterization of the porous network is taken a step further with two other independent methods (electrical and permeability measurements). Electrical properties such as the cementation exponent (1.59 &lt; m &lt; 1.87) and the formation factor (21 &lt; F &lt; 103) do not compare with other granites from the published literature; they point at a type of porosity closer to clastic sedimentary rocks than to crystalline rocks. Permeabilities of the granitoid rocks range from 0.1 to 7.1 mD under an effective pressure of ∼10 MPa. Unlike other fresh to deformed and altered granitoid rocks from the literature compared in this study, this permeability appears to be relatively insensitive to increasing stress (up to ∼40 MPa), with implications for the nature of the porous network, again, behaving more like cemented clastic rocks than fractured crystalline rocks. Other analyzed lithologies include suevite and impact melt rocks. Relatively low permeability (10−3 mD) measured in melt-rich facies suggest that, at the matrix scale, these lithologies cutting through more permeable peak-ring granitoid rocks may have been a barrier to fluid flow, with implications for hydrothermal systems. © 2022 The Authors. 2022 10.1029/2021JB023801 Journal of Geophysical Research: Solid Earth 127 Géosciences Montpellier, Université de Montpellier (UMR5243), CNRS, Montpellier, France; Lunar and Planetary Institute, Universities Space Research Association, Houston, TX, United States; Institut de Chimie des Milieux et des Matériaux de Poitiers (IC2MP), Université de Poitiers, Poitiers, France; Department of Chemistry, University of Helsinki, Helsinki, Finland 5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85134075567&doi=10.1029%2f2021JB023801&partnerID=40&md5=99cc2f0b0feff8d5307192e98b684049 cited By 0 E. Le Ber D. Loggia N. Denchik J. Lofi D.A. Kring P. Sardini M. Siitari-Kauppi P. Pezard G. Olivier IODP-ICDP Expedition 364 Science Party article Mesimeri2022334 On 2020 December 23, a seismic crisis initiated in the western Corinth Gulf offshore Marathias, lasted several months, and generated thousands of small magnitude earthquakes. The Gulf of Corinth is well known for earthquake swarm occurrence and short-lived burst-like earthquake sequences, mostly triggered by crustal fluids. Here, we perform a detailed seismic analysis aiming to identifying earthquake clusters within the seismic crisis and define their spatial and temporal characteristics. Thanks to the dense seismic station coverage in the area, operated by the Hellenic Unified Seismological Network and Corinth Rift Laboratory, we relocate shallow seismicity and compile a high-resolution earthquake catalogue containing ∼1400 earthquakes spanning the first two months of the seismic crisis. We identify 19 earthquake clusters by applying spatio-temporal criteria and define the geometry (strike and dip) using principal component analysis for 11 of them. Our results are consistent with moment tensor solutions computed for the largest earthquake in each cluster. A striking feature of the seismic activity is the west-towards-east migration with a notable increase in Vp/Vs values for each cluster and a slight increase of the dip angle for the identified fault segments. Furthermore, we find that each cluster contains several burst-like, short interevent time, repeating earthquakes, which could be related to aseismic slip or fluid migration. Overall, we show that the 2020-2021 seismic crisis consists of earthquake clusters that bifurcate between swarm-like and main shock-aftershock-like sequences and ruptured both north- and south-dipping high-angle fault segments. The 2020-2021 seismic activity is located between 5 to 8 km, shallower than the low angle north-dipping (∼10°) seismic zone which hosts long-lived repeating sequences at ∼9-10 km depth. This study supports a hypothesis that the low-angle north-dipping seismicity defines the brittle-ductile transition in the western Corinth Gulf, with seismic bursts occurring at shallower depths in the crust. © 2022 The Author(s) 2022. Published by Oxford University Press on behalf of The Royal Astronomical Society. Article 2022 English 0956540X 10.1093/gji/ggac081 Geophysical Journal International 230 Oxford University Press 334 – 348 1 Greece; Gulf of Corinth; Ionian Sea; Mediterranean Sea; Faulting; Offshore oil well production; Principal component analysis; Continental tectonics: Extensional; Fault strain; Fracture strain; Fracture, fault, and high strain deformation zone; High strain deformation zones; Multi-segment; Offshores; Seismic activity; Seismicity and tectonics; Small-magnitude earthquakes; deformation; extensional tectonics; fault; fracture zone; P-wave; rupture; S-wave; seismicity; strain analysis; Earthquakes https://www.scopus.com/inward/record.uri?eid=2-s2.0-85127866988&doi=10.1093%2fgji%2fggac081&partnerID=40&md5=f4ddf4ee04e0e3fc8e96219000f90298 Cited by: 5 Maria Mesimeri Athanassios Ganas Kristine L Pankow article Müller2022 Article 2022 10.1038/s41598-022-10217-9 Scientific Reports 12 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85128908758&doi=10.1038%2fs41598-022-10217-9&partnerID=40&md5=6a0f4f9158bb51f6ab827081eb545e2b Cited by: 10; All Open Access, Gold Open Access, Green Open Access Daniela Müller Ina Neugebauer Yoav Ben Dor Yehouda Enzel Markus J. Schwab Rik Tjallingii Achim Brauer article burschil2022near 2022 Near Surface Geophysics 20 Wiley Online Library 331--348 4 Thomas Burschil Hermann Buness Cedric Schmelzbach article Han20223271 With large cumulative thickness and obvious gas-bearing characteristics, the Songliao Continental Scientific Drilling SK-2 Well has many anomalous gas logging intervals in deep Shahezi formation, revealing that the deep lacustrine shale strata has good prospects for exploration in the Songliao Basin. Using conventional and special logging methods, combined with the core test data, shale reservoir evaluation was carried out in 3 700 − 4 500 m interval of Shahezi formation,logging curve overlay and intersection graph methods were used to identify shale gas reservoirs, the parameters of total organic carbon mass fraction(w(TOC)), porosity, permeability, brittleness and total gas content of shale reservoirs were analyzed quantitatively and interpretation models and calculation methods were established. The results show that the deep lacustrine Shahezi shale gas reservoirs show the characteristics of high natural gamma, high resistivity, low uranium(U), low sonic differential time, low density and low compensation neutrons. The w(TOC) is high in part intervals of 3 700−4 500 m, and the average w(TOC) of some intervals is above 2%. The porosity is between 0.28% − 8.45%, the permeability is (0.002 − 0.509) ×10−3 μm2, the brittleness index is in the range of 19.86%−67.87%, and the total gas content is 1.79−2.57 m3/t. Generally, the deep lacustrine shale reservoirs are characterized by low porosity and low permeability in Songliao Basin and there are many gas-bearing intervals. The 3 722−3 762 m, 3 820−3 860 m, 4 100−4 150 m and 4 400−4 460 m intervals are classified as Type I gas-bearing reservoirs, and the 3 890−3 940 m, 4 220−4 280 m and 4 320−4 360 m intervals are Type II gas-bearing reservoirs, which have the potential for shale gas resource development. © 2022 Central South University of Technology. All rights reserved. Article 2022 Chinese 16727207 10.11817/j.issn.1672-7207.2022.09.001 Zhongnan Daxue Xuebao (Ziran Kexue Ban)/Journal of Central South University (Science and Technology) 53 Central South University of Technology 3271 – 3286 9 Brittleness; Energy resources; Fracture mechanics; Gas permeability; Gases; Low permeability reservoirs; Oil bearing formations; Organic carbon; Petroleum prospecting; Petroleum reservoir evaluation; Petrophysics; Plasticity; Shale gas; Well logging; Bearing characteristic; Case-studies; Continental scientific drillings; Gas content; Lacustrine shale; Logging evaluation; Shahezi formations; Shale gas reservoirs; SK-2 well; Songliao basin; Porosity https://www.scopus.com/inward/record.uri?eid=2-s2.0-85140354588&doi=10.11817%2fj.issn.1672-7207.2022.09.001&partnerID=40&md5=e76647d40e8d4544d06e8d3d355e3c06 Cited by: 0 Shuangbiao Han Xin Du Songtao Bai Chengshan Wang article Horsfield202216750 Free hydrogen detected in the Songke-2 well (Songliao Basin, China) has a strong crustal contribution. Here we evaluate whether the source could be the organic matter in Lower Cretaceous coals and shales, and extend our findings regionally. We could establish the rapid growth of aromatic ring systems, forming hydrogen, methane and pyrobitumen, using high resolution mass spectrometry. Molecular hydrogen is generated after late hydrocarbon gas generation is complete, concluding at Rr = 5.0%. The kinetic parameters of molecular hydrogen formation were constructed by subtracting the hydrogen associated with hydrocarbon formation from the total hydrogen, as measured by extensive open system pyrolysis experiments. This new insight was achieved using a CH4–H2 stoichiometric balance. Generalised calculations indicate that the yield per unit rock volume closely resembles that of economic shale gas in the Barnett Shale, though storage in organic matrices is unlikely in this depositional setting. While the prolific generation of hydrogen from organic sources appears to be a reality in the Songliao basin, the free H2 in the Songke-2 mudstream coming from this source must most likely have migrated into the basement rocks mainly from lateral equivalents of the Shahezi rather than from the drilled section itself. © 2022 Hydrogen Energy Publications LLC 2022 English 03603199 10.1016/j.ijhydene.2022.02.208 International Journal of Hydrogen Energy 47 Elsevier Ltd 16750-16774 GEOS4 GmbH, Peter-Huchel-Chaussee 88, Michendorf, 14552, Germany; State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing, China; College of Geoscience and Surveying Engineering, China University of Mining and Technology, Beijing, China; Bundesanstalt für Geowissenschaften und Rohstoffe (BGR) Geozentrum Hannover, Stilleweg 2, Hannover, 30655, Germany; Chair of Petroleum Geology, Montanuniversitaet LeobenA-8700, Austria; German Research Centre for Geosciences (GFZ), Telegrafenberg, Potsdam, Germany 38 Hydrogen storage; Kinetic theory; Molecular physics, Aromatization and cracking; Hydrogen trapping; Hydrogen trapping and storage; Kinetic models; Molecular hydrogen; Natural maturity series; Natural organic hydrogen; Natural organics; Organic sources; Songliao basin, Mass spectrometry https://www.scopus.com/inward/record.uri?eid=2-s2.0-85129771924&doi=10.1016%2fj.ijhydene.2022.02.208&partnerID=40&md5=e5a1dd4f7a17c18f146a593d94ebee20 cited By 5 B. Horsfield N. Mahlstedt P. Weniger D. Misch S. Vranjes-Wessely S. Han C. Wang article Wetzel2022885 The western Snake River Plain (WSRP) in southwest Idaho has been characterized as an intracontinental rift basin but differs markedly in topography and style from other Cordilleran extensional structures and structurally from the down-warped lava plain of the eastern Snake River Plain. To investigate mechanisms driving extension and topographic evolution, we sampled granitoid bedrock from Cretaceous and Eocene-aged plutons from the mountainous flanks of the WSRP to detail their exhumation history with apatite (U-Th)/He (AHe) thermochronometry. AHe cooling dates from seventeen samples range from 7.9 ± 1.4 Ma to 55 ± 10 Ma. Most cooling dates from Cretaceous plutons adjacent to the WSRP are Eocene, while Eocene intrusions from within the Middle Fork Boise River canyon ~35 km NE of the WSRP yield Miocene cooling dates. The AHe dates provide evidence of exhumation of the Idaho batholith during the Eocene, supporting a high relief landscape at that time, followed by decreasing relief. The Miocene AHe dates show rapid cooling along the Middle Fork Boise River that we take to indicate focused river incision due to base level fall in the WSRP. Eocene AHe dates limit magnitudes of exhumation and extension on the flanks of the WSRP during Miocene rift formation. This suggests extension was accommodated by magmatic intrusions and intrabasin faults rather than basin-bounding faults. We favor a model where WSRP extension was related to Columbia River Flood Basalt eruption and enhanced by later eruption of the Bruneau-Jarbidge and Twin Falls volcanic fields, explaining the apparent difference with other Cordilleran extensional structures. © 2022. The Authors. All Rights Reserved. 2022 English 1553040X 10.1130/GES02453.1 Geosphere 18 Geological Society of America 885-909 Department of Geography and Geological Sciences, University of Idaho, 875 Perimeter Drive, MS3022, Moscow, ID 83844, United States 2 Apatite; Basalt; Cooling; Tectonics; Topography, Idaho Batholith; Magmatic intrusions; Magmatic process; Miocene; Plutons; Rapid cooling; Rift basin; Snake river plains; Thermochronometry; U-Th/He thermochronology, Rivers, apatite; bedrock; exhumation; granitoid; magmatism; pluton; relief; rift zone; thermochronology; uranium series dating, Idaho; Snake River Plain; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-85129728710&doi=10.1130%2fGES02453.1&partnerID=40&md5=bb65e9f963aa59b4fce762e52de58c39 cited By 0 K.F. Wetzel J.R. Stanley article Foerster2022805 Article 2022 10.1038/s41561-022-01032-y Nature Geoscience 15 805 – 811 10 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85138766380&doi=10.1038%2fs41561-022-01032-y&partnerID=40&md5=34ff1276ea68c9b4e61c315ff680cee7 Cited by: 36; All Open Access, Green Open Access, Hybrid Gold Open Access Verena Foerster Asfawossen Asrat Christopher Bronk Ramsey Erik T. Brown Melissa S. Chapot Alan Deino Walter Duesing Matthew Grove Annette Hahn Annett Junginger Stefanie Kaboth-Bahr Christine S. Lane Stephan Opitz Anders Noren Helen M. Roberts Mona Stockhecke Ralph Tiedemann Céline M. Vidal Ralf Vogelsang Andrew S. Cohen Henry F. Lamb Frank Schaebitz Martin H. Trauth article Zhang2022448 The Cretaceous has been considered a “high-fire” world accompanied by widespread by-products of combustion in the rock record. The mid-Cretaceous oceanic anoxic event 1b (OAE1b) is marked by one of the major perturbations in the global carbon cycle characterized by deposition of organic-rich sediments in both marine and terrestrial settings. However, our understanding is still limited on changes in wildfire activity during OAE1b period. Here, we carried out a comprehensive analysis, including organic carbon isotope (δ13Corg), total organic carbon (TOC), coal petrology, trace elements, and pyrolytic polycyclic aromatic hydrocarbons (pyroPAHs), of coal seams of the middle Aptian to early Albian Shahezi Formation from borehole SK-2 in Songliao Basin, Northeast China. Two negative δ13Corg excursions in the Shahezi Formation can be corresponded with the 113/Jacob and Kilian sub-events of OAE1b. Moreover, the intensive peatland wildfires have been identified during the sub-event periods of OAE1b based on the co-occurrence of high abundance of charcoal and pyroPAHs at that time. In addition, Sr/Ba, Sr/Cu and Sr/Rb ratios demonstrate that enhanced peatland wildfires were controlled by dryer climate conditions owing to episodic northward migration of arid zones in East Asia related with rising global temperature during the sub-events of OAE1b. The climate-driven extensive wildfire activity in the mid-latitude terrestrial ecosystems can be a contributing factor for OAE1b through the increased flux of nutrients fuelling primary producers in the lake and marine environments and leading to more speculative anoxia to allow the deposition of organic-rich sediments. Our results provide essential understanding of the importance of wildfires in driving mechanism of oceanic anoxic events (OAEs) in Earth's history. © 2022 The Author(s) 2022 English 20953836 10.1016/j.jop.2022.06.002 Journal of Palaeogeography 11 Elsevier B.V. 448-467 Shandong Provincial Key Laboratory of Depositional Mineralization and Sedimentary Minerals, College of Earth Sciences and Engineering, Shandong University of Science and Technology, Shandong Province, Qingdao, 266590, China; Institute of Earth Sciences, China University of Geosciences, Beijing, 100083, China; School of Earth Sciences and Resources, China University of Geosciences, Beijing, 100083, China; Chinese Academy of Geological Sciences, Beijing, 100037, China 3 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85133760989&doi=10.1016%2fj.jop.2022.06.002&partnerID=40&md5=475829a643bbb2af68906806b84d8df3 cited By 0 Z.-H. Zhang D.-W. Lü T.-T. Wang D.-Z. An H.-Y. Liu D.-D. Wang C.-S. Wang article Gupta2022 Abstract: Anthropogenic activities such as gold and coal mining, oil and gas production, filling of artificial water reservoirs, harnessing of geothermal energy, etc., have induced/triggered earthquakes. Koyna dam, located in the Deccan volcanic province of India, was impounded in 1962, and soon after tremors were reported from the vicinity of Koyna dam. The largest triggered earthquake of magnitude (M) 6.3 occurred on 10 December 1967. The triggered earthquakes have continued until now and the region has experienced 22 events of an M~5, over 200 events of an M~4 and several thousand smaller events. The reservoir-triggered seismicity has continued until 2021, which is unique. Some of the early investigations, leading to drilling of a 3 km deep pilot borehole at Koyna for near-field studies of earthquakes, and a few recent results are summarised in this paper. Research highlights: Koyna, located near the west coast of India, in the Deccan volcanic province is one of the most prominent sites of artificial water reservoir-triggered seismicity (RTS). Triggered earthquakes started soon after the impoundment of Shivaji Sagar lake created by Koyna dam in 1962 and have continued until now.Unlike other RTS sites where triggered earthquakes did not continue for long, Koyna is still active, and it is estimated that RTS may continue for another one to two decades.Detailed field work and analyses of earthquake data demonstrated that Koyna is a very suitable site for near-field studies of earthquakes: an observation that is much needed to validate earthquake genesis models.International Continental Drilling Programme sponsored workshops and participation of experts from all over the world helped in deciding to dig a 3 km deep pilot borehole. The borehole was completed in June 2017.Recent research studies further demonstrated that the Koyna region is under critical stress.Studies under progress would help in designing the proposed ~7 km deep borehole laboratory. © 2022, Indian Academy of Sciences. 2022 English 23474327 10.1007/s12040-021-01780-2 Journal of Earth System Science 131 Springer CSIR-National Geophysical Research Institute, Telangana, Hyderabad, 500 007, India 1 borehole geophysics; earthquake event; human activity; laboratory method; reservoir; seismicity, India; Koyna Dam; Maharashtra https://www.scopus.com/inward/record.uri?eid=2-s2.0-85121444731&doi=10.1007%2fs12040-021-01780-2&partnerID=40&md5=a952c8bcbef0a06be8b25abd8c1a87ac cited By 1 H.K. Gupta article lescoutre_large-scale_2022 The Fennoscandian Shield in central Sweden displays a complex structural and compositional architecture that is mainly related to the Proterozoic history of the Baltica paleocontinent. In its western parts, the Precambrian basement is covered by the allochthonous rocks of the Caledonide orogen, and direct information about the underlying crust is restricted to a few unevenly distributed basement windows in western Sweden and Norway. In this study, we use preliminary results from the second borehole of the Collisional Orogeny in the Scandinavian Caledonides project (COSC-2), new gravity data, forward gravity, and magnetic modeling and interpretation of seismic reflection profiles to assess the 3-D architecture of the basement. Our results reveal a wide (∼100 km) and dense network of mainly flat-lying and saucer-shaped dolerites intruding the volcanic and granitic upper crustal rocks of the Transscandinavian Igneous Belt. Similar intrusion geometries related to 1.2 Ga dolerites can be recognized in the Fennoscandian Shield. We discuss that the formation of these sill complexes occurred in a lithologically and structurally heterogeneous crust during transtension, which is in disagreement with the current understanding of sill emplacement that involves crustal shortening, layering, or anisotropy of the host rock. Our seismic interpretation and the structural observations from the COSC-2 drilling show that part of the Caledonian-related basement deformation was localized along the margins of the dolerite sheets. We propose that the dolerite intrusion geometry, akin to a flat-ramp geometry, guided the basement deformation during the Caledonian orogeny. 2022 mar 0016-7606 10.1130/B36202.1 GSA Bulletin https://doi.org/10.1130/B36202.1 Rodolphe Lescoutre Bjarne Almqvist Hemin Koyi Théo Berthet Peter Hedin Olivier Galland Sonia Brahimi Henning Lorenz Christopher Juhlin article Tierney2022 The eastern Mediterranean is projected to experience increases in drought and extreme rainfall in response to rising greenhouse gas emissions. Paleoclimate records from this region are crucial to further constrain the response of the water cycle to a globally warmer climate. Of these, the Dead Sea lacustrine record, collected by the Dead Sea Deep Drilling Project (DSDDP), provides a detailed history of climate change over the past 200,000 years and documents large-magnitude changes in regional water balance. Here, we analyze leaf wax isotopes (δDwax, δ13Cwax) on DSDDP 5017-1 and compare results to other proxies analyzed on the same core. The δDwax record closely resembles the speleothem δ18O record from nearby Soreq Cave, suggesting that both record a regionally coherent signature of glacial-interglacial cycles and the interplay between winter season rainfall and large-scale expansion and contraction of the Afro-Asian monsoon system. Principal components analysis of the pollen and core lithology shows that the first-order driver of variability in the Dead Sea paleoclimate record is global temperature, which controls effective moisture by modulating atmospheric evaporative demand. Leaf wax, pollen, and core lithology all suggest radical changes in the annual cycle of precipitation during the peak of the Last Interglacial. We hypothesize that the Dead Sea Basin experienced a dual-rainfall regime during this time, with intensified winter storms and a summer monsoon season. While these changes were driven by the Earth's precessional cycle, model simulations suggest a similar expansion of the African monsoon domain into the Arabian Peninsula under elevated CO2 levels. The Last Interglacial climate of the DSB provides a glimpse of what future climate in the southeastern Mediterranean region could look like. © 2022 Elsevier Ltd 2022 English 02773791 10.1016/j.quascirev.2022.107613 Quaternary Science Reviews 289 Elsevier Ltd Department of Geosciences, The University of Arizona, 1040 E 4th St., Tucson, AZ 85721, United States; The Fredy & Nadine Herrmann Institute of Earth Sciences, The Hebrew University of Jerusalem, Jerusalem, 91904, Israel; Interuniversity Institute for Marine Sciences, Eilat, 88103, Israel; Department of Earth Sciences, Syracuse University, Syracuse, NY 13210, United States Atmospheric thermodynamics; Climate change; Expansion; Gas emissions; Greenhouse gases; Lithology; Principal component analysis; Rain; Storms, Dead sea; Deep drilling; Drilling projects; Isotope of precipitation; Last interglacial; Leaf wax; Levant climate; Paleoclimate records; Pollen; δD, Isotopes, annual cycle; climate change; drought; greenhouse gas; historical record; hydrological cycle; hydrometeorology; Last Interglacial; paleoclimate; pollen; precipitation (chemistry); Quaternary; speleothem; wax, Arabian Peninsula; Dead Sea; Israel; Jerusalem [Israel]; Levant; Mediterranean Region; Soreq Cave https://www.scopus.com/inward/record.uri?eid=2-s2.0-85132811081&doi=10.1016%2fj.quascirev.2022.107613&partnerID=40&md5=c6cf1c6df269962adf3e26ebf98c31c8 cited By 1 J.E. Tierney A. Torfstein T. Bhattacharya article Rodríguez-Tovar2022 To fully assess the resilience and recovery of life in response to the Cretaceous-Paleogene (K-Pg) boundary mass extinction ~ 66 million years ago, it is paramount to understand biodiversity prior to the Chicxulub impact event. The peak ring of the Chicxulub impact structure offshore the Yucatán Peninsula (México) was recently drilled and extracted a ~ 100 m thick impact-generated, melt-bearing, polymict breccia (crater suevite), which preserved carbonate clasts with common biogenic structures. We pieced this information to reproduce for the first time the macrobenthic tracemaker community and marine paleoenvironment prior to a large impact event at the crater area by combining paleoichnology with micropaleontology. A variable macrobenthic tracemaker community was present prior to the impact (Cenomanian–Maastrichtian), which included soft bodied organisms such as annelids, crustaceans and bivalves, mainly colonizing softgrounds in marine oxygenated, nutrient rich, conditions. Trace fossil assemblage from these upper Cretaceous core lithologies, with dominant Planolites and frequent Chondrites, corresponds well with that in the overlying post-impact Paleogene sediments. This reveals that the K-Pg impact event had no significant effects (i.e., extinction) on the composition of the macroinvertebrate tracemaker community in the Chicxulub region. © 2022, The Author(s). 2022 10.1038/s41598-022-15566-z Scientific Reports 12 Departamento de Estratigrafía y Paleontología, Universidad de Granada, Granada, Spain; Research Unit: Analytical, Environmental and Geo-Chemistry, Department of Chemistry, Vrije Universiteit Brussel, AMGC-WE-VUB, Pleinlaan 2, Brussels, 1050, Belgium; Laboratoire G-Time, Université Libre de Bruxelles, Av. F.D. Roosevelt 50, Brussels, 1050, Belgium; Centro de Astrobiologia CSIC-INTA, Torrejon de Ardoz, Spain; Institute for Geophysics, Jackson School of Geosciences, University of Texas at Austin, Austin, United States; Department of Geological Sciences, Jackson School of Geosciences, University of Texas at Austin, Austin, United States; Center for Planetary Systems Habitability, University of Texas at Austin, Austin, United States; Department of Geosciences, University of Alaska Fairbanks, Fairbanks, AK, United States; Department of Geosciences, The Pennsylvania State University, College town, United States; Faculty of Sciences (FALW), Vrije Universiteit Amsterdam, Amsterdam, Netherlands; Department of Geosciences, Auburn University, Auburn, AL, United States 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85133415149&doi=10.1038%2fs41598-022-15566-z&partnerID=40&md5=47c7880c77a3fe31a9f2153bf9693c3e cited By 0 F.J. Rodríguez-Tovar P. Kaskes J. Ormö S.P.S. Gulick M.T. Whalen H.L. Jones C.M. Lowery T.J. Bralower J. Smit Jr. King S. Goderis P. Claeys article kelemen2022listvenite This paper provides an overview of research on core from Oman Drilling Project Hole BT1B and the surrounding area, plus new data and calculations, constraining processes in the Tethyan subduction zone beneath the Samail ophiolite. The area is underlain by gently dipping, broadly folded layers of allochthonous Hawasina pelagic sediments, the metamorphic sole of the Samail ophiolite, and Banded Unit peridotites at the base of the Samail mantle section. Despite reactivation of some faults during uplift of the Jebel Akdar and Saih Hatat domes, the area preserves the tectonic “stratigraphy” of the Cretaceous subduction zone. Gently dipping listvenite bands, parallel to peridotite banding and to contacts between the peridotite and the metamorphic sole, replace peridotite at and near the basal thrust. Listvenites formed at less than 200°C and (poorly constrained) depths of 25–40 km by reaction with CO2-rich, aqueous fluids migrating from greater depths, derived from devolatilization of subducting sediments analogous to clastic sediments in the Hawasina Formation, at 400°–500°. Such processes could form important reservoirs for subducted CO2. Listvenite formation was accompanied by ductile deformation of serpentinites and listvenites—perhaps facilitated by fluid-rock reaction—in a process that could lead to aseismic subduction in some regions. Addition of H2O and CO2 to the mantle wedge, forming serpentinites and listvenites, caused large increases in the solid mass and volume of the rocks. This may have been accommodated by fractures formed as a result of volume changes, mainly at a serpentinization front. © 2022. American Geophysical Union. All Rights Reserved. 2022 English 21699313 10.1029/2021JB022352 Journal of Geophysical Research: Solid Earth 127 Wiley Online Library e2021JB022352 Lamont Doherty Earth Observatory, Columbia University, Palisades, NY, United States; Department of Geosciences, University of Calgary, Calgary, AB, Canada; Géosciences Montpellier, Université de Montpellier, CNRS, Montpellier, France; Kochi Institute for Core Sample Research, JAMSTEC, Kochi, India; Department of Earth & Planetary Sciences, McGill University, Montreal, QC, Canada; Department of Earth, Planetary & Space Sciences, University of California, Los Angeles, CA, United States; Department of Geological Sciences, University of Colorado, Boulder, CO, United States; Tectonics & Geodynamics, RWTH Aachen University, Aachen, Germany; Department of Earth, Environmental and Planetary Sciences, Brown University, Providence, RI, United States; Department of Earth Science, University of California, Santa Barbara, CA, United States; Department of Geological Sciences, University of Texas, Austin, TX, United States; Department of Earth Science, University of Bergen, Bergen, Norway; Department of Ocean & Earth Science, National Oceanography Centre Southampton, Southampton, United Kingdom; Alara Resources Ltd., Muscat, Oman; School of Geography, Earth and Environmental Sciences, University of Plymouth, Plymouth, United Kingdom; Department of Earth & Planetary Sciences, Nagoya University, Nagoya, Japan; Department of Geology, Niigata University & VERC IMG JAMSTEC, Niigata, Japan; Oman Water Society & Middle East Desalination Research Center, Muscat, Oman; Department of Earth and Environmental Sciences, Columbia University, New York, NY, United States; School of Ocean and Earth Science, University of Southampton, Southampton, United Kingdom; Geography, Earth and Environmental Sciences, Plymouth University, Plymouth, United Kingdom; School of Earth and Ocean Sciences, Cardiff University, Cardiff, United Kingdom; Department of Petrology, Center de Recherches Pétrographiques et Géochimiques (CRPG), Vandœuvre-lés-Nancy, France; Department of Geosciences, CRPG-CNRS Université de Lorraine, France; Department of Earth Sciences, Federal Institute of Technology, Zurich, Switzerland; Institute of Geosciences, Christian-Albrecht University of Kiel, Kiel, Germany; Department of Géosciences, CNRS Université de Montpellier, Montpellier, France; Department of Applied Geosciences, German University of Technology in Oman, Oman; Department of Earth, Planetary and Space Sciences, University of California, Los Angeles, CA, United States; Institute for Mineralogy, Leibniz University of Hanover, Hanover, Germany; Institute of Geosciences, Kiel University, Kiel, Germany; Department of Geosciences, Université de Montpellier, Montpellier, France; Department of Geological Sciences, University of Colorado, Boulder, CO, United States; Department of Earth Sciences, Kanazawa University, Kanazawa, Japan; Department of Geosciences, CNRS Université de Montpellier, Montpellier, France; Earth, Ocean and Atmospheric Sciences, University of British Columbia, Vancouver, BC, Canada 2 carbon cycle; drilling; ductile deformation; mantle; mass transfer; ophiolite; subduction zone; ultramafic rock, Oman https://www.scopus.com/inward/record.uri?eid=2-s2.0-85131513917&doi=10.1029%2f2021JB022352&partnerID=40&md5=33a9a1a01c09c7008cae841a58027261 cited By 5 Peter B Kelemen Juan Obeso James A Leong Marguerite Godard Keishi Okazaki Alissa J Kotowski Craig E Manning Eric T Ellison Manuel D Menzel Janos L Urai others article Chen2022 Deep-time records from greenhouse climate periods (e.g., the Late Cretaceous) provide a reference point for understanding how high atmospheric CO2 concentrations influence precipitation in the mid-latitude Northern Hemisphere (e.g., East Asia). In this study, we quantitatively reconstruct mean annual precipitation (MAP) in East Asia during the latest Cretaceous through the earliest Paleogene (~76–65.5 Ma), based on a well-studied paleosol sequence from the Sifangtai and Mingshui Formations from the SK-1n scientific borehole in the Songliao Basin, northeastern China. We use several proxies, including sedimentary-based observational proxies (e.g., depth to the calcic horizon, DTC) and elemental geochemistry proxies in the paleosol B horizon (e.g., the chemical index of alteration minus potassium, CIA-K; the calcium‑magnesium weathering index, CALMAG), which show the consistency with weathering proxies and previously published isotopic records. Changes in the MAP are associated with warming and cooling events. In the warciaming period (e.g., at ~69.5–68.5 Ma), an increase in the land-sea thermal contrast led to an expanded, enhanced, poleward-shifted thermal low-pressure system over the East Asian continent, which triggered an enhanced hydrological cycle and increasing MAP in the Songliao Basin. During the cooling period (e.g., at ~72.5–69.5 Ma and ~68.5–66.5 Ma), weakened East Asian monsoon and strengthened equatorward-shifted westerlies allowed for colder and arid air masses to encroach upon the Songliao Basin, which led to decreased MAP. Changes in MAP across the K-Pg boundary coincide with climate fluctuations and catastrophic geological events. Furthermore, our work compares three warming intervals in deep-time (middle Maastrichtian, late Maastrichtian and earliest Paleogene) with Shared Socio-economic Pathway scenarios used by the IPCC for the end of the 21st century, and indicates MAP increases in East Asia with ongoing anthropogenic CO2 emissions. © 2022 Elsevier B.V. Article 2022 English 09218181 10.1016/j.gloplacha.2022.103900 Global and Planetary Change 216 Elsevier B.V. China; Songliao Basin; Carbon dioxide; Greenhouses; Cretaceous; East Asia; Greenhouse climates; Late cretaceous; Mean annual precipitation; Midlatitudes; Palaeosols; Paleogene; Songliao basin; Time records; air mass; carbon dioxide; concentration (composition); cooling; Cretaceous; hydrological cycle; low pressure system; Northern Hemisphere; paleosol; precipitation (climatology); proxy climate record; warming; Weathering https://www.scopus.com/inward/record.uri?eid=2-s2.0-85135345767&doi=10.1016%2fj.gloplacha.2022.103900&partnerID=40&md5=de7da9654d6610d6df513b902c6a426d Cited by: 2 Jiquan Chen Yuan Gao Daniel E. Ibarra Jianming Qin Chengshan Wang article Han2022 Multi-type unconventional gas-bearing reservoirs with different lithologies and gas accumulation potential occur in the deep part of the Songliao basin. However, the reservoirs are non-homogeneous, the gas components differ substantially, and not all types of gas-bearing reservoirs have been identified or evaluated. The International Continental Scientific Drilling Program (ICDP) is used as an example to conduct qualitative and quantitative evaluations of deep multi-type unconventional gas-bearing reservoirs using conventional and specialized logging data. The core test data are used to determine the physical properties. The porosity and permeability are compared and analyzed using different methods and models. The results show that the reservoirs have low to ultra-low porosity and ultra-low permeability. Based on the comparison of the rock mechanical parameters and mineral composition, brittleness evaluation parameters are proposed for different types of deep reservoirs in the study region. The mineral brittleness index is highly consistent with the brittleness index based on rock mechanics. An identification method for deep multi-type gas-bearing reservoir and a classification approach for different gas properties are established based on the logging response and parameter interpretation. The methane gas reservoirs have low density (DEN) and low compensated neutron logging (CNL) values and high acoustic (AC) time difference and high resistivity (RT) values. The CO2 gas reservoirs have lower RT values and higher CNL values than the hydrocarbon gas reservoirs. The comprehensive analysis of deep gas source rock conditions and of the source-reservoir relationship provides insights for the evaluation of deep multi-type unconventional gas reservoirs. The discovery of high hydrogen content is of significant importance for developing new areas for deep natural gas exploration. © 2022 China University of Geosciences (Beijing) and Peking University Article 2022 English 16749871 10.1016/j.gsf.2022.101451 Geoscience Frontiers 13 Elsevier B.V. College of Geoscience and Surveying Engineering, China University of Mining and Technology, Beijing, 100083, China; State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum, Beijing, 102249, China; China Petroleum Logging Co. Ltd, Xi'an, 710077, China; State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing, 100083, China 6 China; Songliao Basin; drilling; hydrocarbon exploration; hydrocarbon reservoir; logging (geophysics); natural gas; reservoir characterization https://www.scopus.com/inward/record.uri?eid=2-s2.0-85136114571&doi=10.1016%2fj.gsf.2022.101451&partnerID=40&md5=03867a5a25307a89512458778d54394f Cited by: 4; All Open Access, Gold Open Access Shuangbiao Han Chaohan Xiang Xin Du Linfeng Xie Songtao Bai Chengshan Wang article Tusch2022 Article 2022 10.1073/pnas.2120241119 Proceedings of the National Academy of Sciences of the United States of America 119 18 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85129778446&doi=10.1073%2fpnas.2120241119&partnerID=40&md5=73f9a2d52aeb21cc4d8cf4d027711168 Cited by: 25; All Open Access, Hybrid Gold Open Access Jonas Tusch J. Elis Hoffmann Eric Hasenstab Mario Fischer-Gödde Chris S. Marien Allan H. Wilson Carsten Münker article Shen2022 We developed an integrated chronology for the non-marine Upper Cretaceous Nenjiang Formation based on high-resolution magnetostratigraphic results and previously published secondary ion mass spectrometry (SIMS) U–Pb zircon analyses of the eastern borehole of the Cretaceous Continental Scientific Drilling (CCSD-SK-II) borehole and two outcrop sections located in different structural provinces of the Songliao Basin, China. Detailed rock magnetic results demonstrated that pseudo-single-domain magnetite and single-domain greigite coexisted in the lacustrine black shales of the Nenjiang Formation, with the latter dominating remanence carriers. The reliable primary remanent magnetizations were isolated, which passed a class A positive reversal test and positive bootstrap reversal test, after correction for inclination shallowing, yielding a high-quality paleopole of 79.6°N/208.4°E, A95 = 2.3°. The borehole sequence and outcrop sections were stratigraphically correlated by combining lithostratigraphy, biostratigraphy, and SIMS U–Pb zircon geochronology. The correlation of the recognized magnetic polarity sequences to the geomagnetic polarity timescale suggests that the Nenjiang Formation from the CCSD-SK-II borehole sequence and the two outcrop sections span from very late chron C34n to very early chron C33r. Furthermore, the age of the Cretaceous Normal Superchron (CNS) termination can be constrained to 82.7 ± 0.6 Ma based on magnetostratigraphy, radiometric dating, and the perfect/typical averaged sediment accumulation rate for Member 1 of the Nenjiang Formation of the borehole sequence. The estimated age obtained in this study accurately represents the age at CNS termination. © 2022 Elsevier Ltd 2022 English 01956671 10.1016/j.cretres.2022.105213 Cretaceous Research 135 Academic Press State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, 100029, China; College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China; Innovation Academy for Earth Science, Chinese Academy of Sciences, Beijing, 100029, China; Key Laboratory of Vertebrate Evolution and Human Origin of Chinese Academy of Sciences, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing, 100044, China; CAS Centre for Excellence in Life and Paleoenvironment, Beijing, 100044, China accuracy assessment; age determination; borehole geophysics; chronostratigraphy; Cretaceous; error correction; geochronology; lithostratigraphy; magnetic susceptibility; magnetostratigraphy; uranium; uranium-lead dating, China; Songliao Basin https://www.scopus.com/inward/record.uri?eid=2-s2.0-85127358163&doi=10.1016%2fj.cretres.2022.105213&partnerID=40&md5=43db93aa377ea684b537bb6e5f445cf8 cited By 3 Z. Shen Z. Yu H. Ye C. Deng H. He article WOS:000853336000003 2022 10.1016/j.gloplacha.2022.103884 GLOBAL AND PLANETARY CHANGE 215 Early Toarcian; Panthalassic Ocean; Sulfur cycle; Pyrite sulfur isotope; Local sedimentary environment Wenhan Chen David B. Kemp Robert J. Newton Tianchen He Chunju Huang Tenichi Cho Kentaro Izumi article Weisenberger2022MeasurementsOT 2022 10.33112/surtsey.15.9 Surtsey research 15 121-126 https://api.semanticscholar.org/CorpusID:253620732 Tobias B. Weisenberger Magnús Tumi Guðmundsson Bjarni Steinar Gunnarsson Steffen L. Jørgensen M.D. Jackson article Lima-Zaloumis2022 Article 2022 10.1038/s43247-022-00551-1 Communications Earth and Environment 3 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85139513072&doi=10.1038%2fs43247-022-00551-1&partnerID=40&md5=3363dc94720b1cc50a24362ac9692c9e Cited by: 9; All Open Access, Gold Open Access, Green Open Access Jon Lima-Zaloumis Anna Neubeck Magnus Ivarsson Maitrayee Bose Rebecca Greenberger Alexis S. Templeton Andrew D. Czaja Peter B. Kelemen Tomas Edvinsson article Nkosi2022 Petrophysical properties of cylindrical core specimens from three boreholes from the International Continental Scientific Drilling Program, the DSeis project, measured at ambient pressure and room temperature conditions in various laboratories are presented and compared with downhole petrophysical data (sonic and density). The measured properties are from sixty-six rock specimens constituting metasediments, metabasalts and intrusives. Seismic velocities were measured using 0.5 MHz P- and S-wave transducers. To investigate the source of seismic reflectivity observed on the 2D legacy seismic data, we computed synthetic seismograms for adjacent rock units using downhole petrophysical data and compared them with seismic reflections from the reflection seismic profile. The experimental measurements show that the metasediments exhibit lower bulk densities and seismic velocities than the metabasalts and intrusive specimens. The porosity was found to be less than 2% for all the samples. No clear trends emerge when the Poisson's ratio is plotted against the P-wave velocities and porosities of the samples. A positive relationship is observed between the bulk modulus and P-wave velocities of the rock samples. The highest calculated reflection coefficients (RC) are associated with the metasediment-intrusive interfaces in all three boreholes. The intrusive-metabasalt and the metasediment-metabasalt interfaces exhibit low RC. Synthetic seismograms reveal strong reflections that coincide with high RC calculated using the bulk density and velocity data. The synthetic seismograms also revealed additional strong reflections that were not identified using the reflection coefficients calculated from the rock specimens, due to core loss in some lithological units. Successful correlations are carried out between the synthetic seismic data and the real seismic data, enabling us to correlate the stratigraphic sequence drilled in the boreholes to the seismic reflections observed on the legacy 2D reflection seismic data. © 2022 Elsevier Ltd Article 2022 English 13651609 10.1016/j.ijrmms.2022.105082 International Journal of Rock Mechanics and Mining Sciences 155 Elsevier Ltd 105082 School of Geosciences, University of the Witwatersrand, Johannesburg, South Africa; Council for Scientific and Industrial Research, Cnr Carlow and Rustenburg Rd, Auckland Park, Johannesburg, South Africa; Ritsumeikan University, Kusatsu, Japan; ETH, Zurich, Switzerland; Moab Khotsong mine, South Africa; Princeton University, United States South Africa; Acoustic wave velocity; Boreholes; Earthquakes; Geophysical prospecting; Infill drilling; Petrophysics; Porosity; Reflection; Rocks; Seismic response; Seismic waves; Shear waves; Stratigraphy; Wave propagation; Well logging; Downholes; Metabasalts; Mining induced earthquake; P-wave velocity; Petrophysical datum; S-wave velocity; Seismic datas; Seismic reflectivity; Sonic logs; Synthetic seismogram; gold mine; mining-induced seismicity; P-wave; physical property; S-wave; seismic reflection; seismic velocity; seismic zone; seismogram; ultrasonics; Lithology https://www.scopus.com/inward/record.uri?eid=2-s2.0-85130462900&doi=10.1016%2fj.ijrmms.2022.105082&partnerID=40&md5=64b73abe4e5ddfe9969bffc149386509 Cited by: 3; All Open Access, Bronze Open Access Nomqhele Z. Nkosi Musa S.D. Manzi Michael Westgate Dave Roberts Raymond J. Durrheim Hiroshi Ogasawara Martin Ziegler Michael Rickenbacher Bennie Liebenberg Tullis C. Onstott article Hernández-Terrones2022 The aim of the study is to evaluate fluids circulation through the Chicxulub crater, and to determine the composition of hydrothermal fluids after the impact. Rock-Eval pyrolysis and fluid inclusion micro-thermometry analyses were performed. The technique has been routinely used for about fifteen years and has become a standard tool for hydrocarbon exploration. Rock-Eval pyrolysis reveals the distribution of organic and mineral carbon affected by the impact and later affected by hydrothermal activity. All measured inclusions are primary and were found in basement samples only. Both the fluid inclusions data and Rock-Eval pyrolysis show that composition and temperature of the fluids changed as the fluids migrated though crater rocks. An evolution of temperatures occurs (vertical, horizontal, or both), from the surface and from the center of the crater; this spatial evolution is consistent with model of Abramov and Kring, showing a thermal evolution of temperature with depth in the crater as well as its influence on the hydrothermal system. Post-impact fluid circulation modifies the temperature distribution. © 2022 Elsevier Ltd 2022 10.1016/j.apgeochem.2021.105194 Applied Geochemistry 137 Universidad Del Caribe, L-1, Mz 1, Esq. Fracc. Tabachines SM 78, Cancún, Quintana Roo CP 77528, Mexico; Institut de Physique Du Globe de Strasbourg, UMR [7516 Ou 7517], CNRS-Université, de Strasbourg EOST, 1 Rue Blessig, Strasbourg Cedex, 67084, France; Unidad de Investigación en Ciencias de La Tierra Campus UNAM Juriquilla, A.P. # 15 JuriquillaQro, Mexico; Dept. of Earth Science and Engineering, Imperial College London SW7 2AZUK, United Kingdom; Institute for Geophysics Jackson School of Geosciences, University of Texas at Austin, Austin, TX 78758, United States; Dept. of Geological Sciences, Jackson School of Geosciences, University of Texas at Austin, Austin, TX 78758, United States; Center for Planetary Systems Habitability, University of Texas at Austin, Austin, TX 78712, United States; SM 312, Mza 7, Chipre 5, Resid. Isla Azul, Cancun, Quintana Roo, Mexico; Lunar and Planetary Institute, USRA, Houston, TX 77058, United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-85122938042&doi=10.1016%2fj.apgeochem.2021.105194&partnerID=40&md5=ccdd2a3f41f463634e3e32404aa27eac cited By 0 L. Hernández-Terrones L. Martínez J. Szamotulski E. González-Partida J.V. Morgan C.M. Lowery S.P.S. Gulick M. Rebolledo-Vieyra D. Kring article Qin2024168 Article 2022 10.3981/j.issn.1000-7857.2022.13.003 Science & Technology Review 40 27-35 13 Z. Wang W. Wang L. Zhang Z. Xi D. An H. Yin J. Yan article green_post-caledonian_2022 The evolution of Fennoscandia following the early Devonian collapse of the Caledonian mountains is a matter of debate, due largely to the scarcity of post-Caledonian cover rocks. The preserved geological record therefore provides only partial documentation of the geological evolution. A more complete understanding is obtained by also considering evidence of rocks that were formerly present but have since been removed. We report apatite fission track data and associated thermal history constraints in 331 samples of Precambrian basement, younger sedimentary cover, Paleozoic and Mesozoic igneous rocks from outcrops and boreholes (up to 6 km depth) across Fennoscandia, which define thirteen phases of cooling (each representing kilometre-scale exhumation) over the last 1100 Myr. Key post-Caledonian episodes began in the intervals 311–307 Ma (late Carboniferous), 245–244 Ma (Middle Triassic), 170–167 Ma (Middle Jurassic), 102–92 Ma (mid-Cretaceous) and 23–21 Ma (early Miocene). These episodes, varying in magnitude, are recognised across Fennoscandia, and their effects are documented in the stratigraphic record and as prominent regional peneplains. The results define a history involving repeated episodes of regional burial and exhumation. Major offsets in Mesozoic paleotemperatures over short distances define kilometre-scale differential vertical displacements, emphasising the tectonic nature of the history. Results from Finland record the same events recognised in Norway and Sweden (though less pronounced), and are not consistent with long-term cratonic stability. The lack of preserved Phanerozoic sedimentary cover in Finland is interpreted to be due to complete removal during multiple episodes of denudation. In southern Norway and Sweden, early Miocene exhumation led to creation of a peneplain, which in Pliocene times was uplifted and dissected, producing the modern landscape. Post-Caledonian exhumation episodes defined here are broadly synchronous with similar events in Greenland, the British Isles and North America. Far-field transmission of plate-tectonic stress and/or mantle processes may explain the vertical movements described here. 2022 jul en 1342-937X 10.1016/j.gr.2022.03.007 Gondwana Research 107 201--234 Exhumation, AFTA, Craton, Missing section, Peneplain https://www.sciencedirect.com/science/article/pii/S1342937X22000892 Paul F. Green Peter Japsen Johan M. Bonow James A. Chalmers Ian R. Duddy Ilmo T. Kukkonen article Lu2022617 Sharp changes in lithology and increases in grain size and sedimentation rate of sedimentary sequences from tectonically active basins are often used to indicate regional neotectonic activity. However, these conventional methods have been challenged by others who argue that the sedimentary evidence used to infer tectonism could be climatically induced. Therefore, some form of independent evidence or sedimentary criteria are required to discriminate between these two alternatives. Seismites, sedimentary structures preserved in lacustrine or marine stratigraphic sequences caused by seismic shaking, are reliable indicators of regional neotectonic activity. Lacustrine/Marine paleoseismology, an emerging cross-field, can extend the record of strong earthquakes and deepen the understanding of fault zone activity by studying seismites preserved in subaqueous sedimentary sequences. In this paper, we use the Dead Sea Basin and Qaidam Basin as examples to understand regional neotectonic activity from the perspective of subaqueous paleoseismology. The Dead Sea Basin is the deepest and largest continental tectonic structure in the world. A 457 m deep core(ICDP Core 5017-1)was recovered from the Dead Sea depocenter(31°30′29″N, 35°28′16″E) during 2010~2011. The bottom of the core was dated back to 220 ka. In situ folded layers and intraclast breccia layer in the core are identified as earthquake indicators, based on their resemblance to the lake outcrop observations of seismites that are known to be earthquake-induced. Based on the Kelvin-Helmholtz instability, we model the ground acceleration needed to produce each seismite by using the physical properties of the Dead Sea deposits. We invert acceleration for earthquake magnitude by considering regional earthquake ground motion attenuation, fault geometry, and other constraints. Based on the magnitude constraints, we develop a 220 ka-long record of MW ≥7 earthquakes. The record comprises 151 MW ≥7 events. The record shows a clustered earthquake recurrence pattern and a group-fault temporal clustering model, and reveals an unexpectedly high seismicity rate on a slow-slipping plate boundary. The Qaidam Basin is the largest topographic depression on the Tibetan Plateau that was formed by the ongoing India-Asia collision. The northeastward growth of the Tibetan Plateau formed a series of sub-parallel NW-SE-trending folds over a distance of ca. 300 km in the western Qaidam Basin. A 723 m deep core was drilled in the basin on the crest of one such fold, the Jianshan Anticline(38°21′9.46″N, 92°16′24.72″E) during 2010~2011. In this study, we focus on the upper 260 m of the core. Paleomagnetic dating constrains the age of the studied core interval to ca. 3.6~1.6 Ma. Sedimentological analysis reveals micro-faults, soft-sediment deformation, slumps, and detachment surfaces preserved in the core interval, which we interpret as paleoearthquake indicators. We recover a 2-Ma seismite sequence comprising 164 MW ≥5 events. The seismite sequence is relatively more complete during 3.6~2.7 Ma, which comprises 126 events and five seismite clusters. This suggests that the rate of tectonic strain accommodated by the folds/thrusts in the region varies in time and thus reveals episodic local deformation. During the clusters, regional deformation is concentrated more in the fold-and-thrust system than along regional major strike-slip faults. © 2022, Science Press (China). All rights reserved. 2022 Chinese 10017410 10.11928/j.issn.1001-7410.2022.03.01 Quaternary Sciences 42 Science Press (China) 617-636 Department of Geology, University of Innsbruck, Innsbruck, 6020, Austria; Geological Survey of Israel, Jerusalem, 9692100, Israel; Department of Geophysics, Tel Aviv University, Tel Aviv, 6997801, Israel; State Key Laboratory of Tibetan Plateau Earth System, Resources and Environment, Institute of Tibetan Plateau Research(TPESRE), Chinese Academy of Sciences, Beijing, 100101, China; Key Laboratory of Continental Collision and Plateau Uplift, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, 100101, China 3 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85136778232&doi=10.11928%2fj.issn.1001-7410.2022.03.01&partnerID=40&md5=c7b30250e81c500efcc3cdb0e3dd461a cited By 0 Y. Lu N. Wetzler S. Marco X. Fang article kleine2022sulfate 2022 10.1016/j.gca.2021.10.016 Geochimica et Cosmochimica Acta 317 Elsevier 65--90 Barbara I Kleine Andri Stefánsson Robert A Zierenberg Heejin Jeon Martin J Whitehouse Kristján Jónasson Gudmundur ‪Ó Fridleifsson Tobias B Weisenberger article Song2022 Article 2022 10.1016/j.gsf.2022.101377 Geoscience Frontiers 13 3 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85126981449&doi=10.1016%2fj.gsf.2022.101377&partnerID=40&md5=de1d71dfa99c306bd23adcf42791c3af Cited by: 18; All Open Access, Hybrid Gold Open Access Ying Song Jianye Ren Keyu Liu Dawei Lyu Xinjie Feng Yuan Liu Andrei Stepashko article Shi2022962 Heat flow data are essential for understanding lithospheric dynamics. As a petroliferous basin, a large number of boreholes have been drilled during hydrocarbon exploration and production in the northern part of Songliao Basin, Northeast China. Meanwhile, the data on crustal structures, core samples and formation temperatures have been accumulated, which provide an opportunity for understanding the thermal state of the basin. Based on the temperature data from both Drilling Stem Test and continuous steady-state logging profiles, together with the systematic analysis of the thermal properties of rock samples, we present a new heat flow map of the northern Songliao Basin with significantly increased number of heat flow sites. The northern Songliao Basin is characterized by relatively high geothermal gradients and high heat flow for sedimentary basins. The heat flow values range from 44.4 to 95.0 mW m-2 with an average of 67.2 ± 12.8 mW m-2, and the geothermal gradients range from 21 to 59 °C km-1 with an overall average of 41.7 °C km-1. Heat production from sedimentary covers accounts for about 4.5 mW m-2 at the site of Well SK-2. Furthermore, based on the crustal structures revealed by previous seismic studies, lithospheric thermal structures are analysed and compared among different structural units of the basin. A thinned thermal lithosphere with a thickness of ∼65 km is found beneath the Central downwarp and the Southeast uplift in which a large part of the heat flow is mantle derived. The Western Slope exhibits a moderate heat flow value and a thicker thermal lithosphere with thickness greater than 110 km. From the perspective of the geothermal state of the lithosphere, the regional geodynamics related to the Mesozoic lithosphere stretching and the subduction of the Pacific Plate are discussed. © 2021 The Author(s). 2022 English 0956540X 10.1093/gji/ggab500 Geophysical Journal International 229 Oxford University Press 962-983 Research Institute of Petroleum Exploration and Development, CNPC, Beijing, 100081, China; College of Energy, Chengdu University of Technology, Chengdu, Sichuan, 610059, China; School of Earth Sciences, Northeast Petroleum University, Daqing, Heilongjiang, 163318, China; School of Mines, China University of Mining and Technology, Xuzhou, Jiangsu, 221116, China; Institute of Geology and Geophysics, Chinese Academy of Science, Beijing, 100029, China 2 Geodynamics; Geothermal energy; Infill drilling; Petroleum prospecting; Sedimentology; Structural geology, Asia; Composition and structure of the continental crust; Dynamics of lithosphere and mantles; Heat generation and transports; Heat-flow; Lithospheric; Northeast China; Sedimentary basin process; Songliao basin, Heat transfer, continental crust; crustal structure; geodynamics; heat flow; heat transfer; lithosphere; mantle; sedimentary basin, China; Songliao Basin https://www.scopus.com/inward/record.uri?eid=2-s2.0-85131666910&doi=10.1093%2fgji%2fggab500&partnerID=40&md5=4194709aa0cab53b8cff465484990859 cited By 1 Y. Shi G. Jiang S. Shi Z. Wang S. Wang S. Hu article WOS:000781695800001 The extinction of the dinosaurs and around three-quarters of all living species was almost certainly caused by a large asteroid impact 66 million years ago. Seismic data acquired across the impact site in Mexico have provided spectacular images of the approximately 200-kilometre-wide Chicxulub impact structure. In this Review, we show how studying the impact site at Chicxulub has advanced our understanding of formation of large craters and the environmental and palaeontological consequences of this impact. The Chicxulub crater’s asymmetric shape and size suggest an oblique impact and an impact energy of about 1023 joules, information that is important for quantifying the climatic effects of the impact. Several thousand gigatonnes of asteroidal and target material were ejected at velocities exceeding 5 kilometres per second, forming a fast-moving cloud that transported dust, soot and sulfate aerosols around the Earth within hours. These impact ejecta and soot from global wildfires blocked sunlight and caused global cooling, thus explaining the severity and abruptness of the mass extinction. However, it remains uncertain whether this impact winter lasted for many months or for more than a decade. Further combined palaeontological and proxy studies of expanded Cretaceous–Palaeogene transitions should further constrain the climatic response and the precise cause and selectivity of the extinction. © 2022, Springer Nature Limited. Review 2022 10.1038/s43017-022-00283-y NATURE REVIEWS EARTH & ENVIRONMENT 3 338-354 Department of Earth Science and Engineering, Imperial College London, London, United Kingdom; Department of Geosciences, Pennsylvania State University, University Park, PA, United States; Senckenberg Biodiversity and Climate Research Centre, Frankfurt am Main, Germany; Earth System Analysis, Potsdam Institute for Climate Impact Research, Member of the Leibniz Association, Potsdam, Germany; Museum für Naturkunde, Leibniz Institute for Evolution and Biodiversity Science, Berlin, Germany; Institute of Geological Sciences, Planetary Sciences and Remote Sensing, Freie Universität Berlin, Berlin, Germany 5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85128065124&doi=10.1038%2fs43017-022-00283-y&partnerID=40&md5=9e926e9d3dc36571643f8a5c616ba5b1 cited By 6 Joanna Morgan Timothy J. Bralower Julia Brugger Kai Wuennemann article Khajehdehi2022 Article 2022 10.1029/2021GL095199 Geophysical Research Letters 49 4 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85125789823&doi=10.1029%2f2021GL095199&partnerID=40&md5=d1efd6bc396106b41994d5457f728424 Cited by: 6; All Open Access, Bronze Open Access Omid Khajehdehi Kamran Karimi Jörn Davidsen conference Supakulopas2022 During impact events, planetary crusts experience high pressures that can impart rocks with shock remanent magnetisation (SRM) if an ambient magnetic field or demagnetise rocks if a field is absent. If rocks experience substantial impact heating or are pressurised above ~40 GPa (inducing melting and recrystallisation) they may instead record a thermo-viscous remanent magnetisation (TVRM) as they cool below their Curie temperatures. Understanding impact re-magnetisation is crucial for studying terrestrial impact craters, but also unraveling the history of long-lived core dynamo fields on other planetary bodies. In this research we studied impact-related re-magnetisation recorded in natural rock samples from the Chesapeake Bay impact crater, Virginia. As a case study, here we discuss the natural remanent magnetisation (NRM) of two samples of different rock types: a suevite (sample I9-UI, depth 1.40 km beneath the ground) and a schist (sample S32, depth 1.67 km beneath the ground) using thermal and alternating field demagnetisation. The suevite represents a sample that contains material that experience impact remelting, whereas the schist represents an unmelted rock. From the NRM spectra, we found that the sample ITH9-UI was remagnetised by TVRM due to impact-related heating, while the sample STH32 shows the indication of shock deformation of magnetic minerals. © 2022 Institute of Physics Publishing. All rights reserved. 2022 English 17426588 10.1088/1742-6596/2145/1/012051 Journal of Physics: Conference Series 2145 IOP Publishing Ltd Chatthong B., Buranachai C., Kalasuwan P., Rakkapao S., Putson C., Soonthornthum B., Aukkaravittayapun S. Division of Physical Science, Faculty of Science, Prince of Songkla University, Songkhla, Hat Yai, 90110, Thailand; Department of Geophysics, Stanford University, Stanford, CA 94305, United States; Department of Earth and Planetary Science, Rutgers University, Piscataway, NJ 08854, United States 1 Rocks, Chesapeake Bay; High pressure; Impact craters; Impact events; Impact heating; Natural remanent magnetization; Planetary bodies; Recrystallisation; Remanent magnetization; Virginia, Magnetization https://www.scopus.com/inward/record.uri?eid=2-s2.0-85123710828&doi=10.1088%2f1742-6596%2f2145%2f1%2f012051&partnerID=40&md5=d41bc5d8f87147e0f8c8bf5e7afcb32f cited By 0 R. Supakulopas S.M. Tikoo article Lu2022 In lakes and oceans, links between modern sediment density flow processes and deposits preserved in long-term geological records are poorly understood. Consequently, it is unclear whether, and if so how, long-term climate changes affect the magnitude/frequency of sediment density flows. One approach to answering this question is to analyze a comprehensive geological record that comprises deposits that can be reliably linked to modern sediment flow processes. To address this question, we investigated the unique ICDP Core 5017-1 from the Dead Sea (the largest and deepest hypersaline lake on the Earth) depocenter covering MIS 7-1. Based on an understanding of modern sediment density flow processes in the lake, we link homogeneous muds in the core to overflows (surface flood plumes, ρflow&lt;ρwater), and link graded turbidites and debrites to underflows (ρflow&gt;ρwater). Our dataset reveals (1) overflows are more prominent during interglacials, while underflows are more prominent during glacials; (2) orbital-scale climate changes affected the flow magnitude/frequency via changing salinity and density profile of lake brine, lake-level, and source materials. © 2022 The Author(s) 2022 English 0012821X 10.1016/j.epsl.2022.117723 Earth and Planetary Science Letters 594 Elsevier B.V. Institute of Geology, University of Innsbruck, Innsbruck, 6020, Austria; Department of Geography, Durham University, Durham, DH1 3LE, United Kingdom; Dr. Moses Strauss Department of Marine Geosciences, University of Haifa, Haifa, 3498838, Israel; Institute of Earth Sciences, Hebrew University of Jerusalem, Jerusalem, 91904, Israel; Department of Geophysics, Tel Aviv University, Tel Aviv, 6997801, Israel Climate change; Deposits; Floods; Glacial geology; Orbits; Sediment transport; Stratigraphy, Dead sea; Flash-floods; Flood plumes; Flow process; Geological record; Hypersaline lakes; Sediment density flows; Sediment transport process; Turbidite; Underflows, Lakes, climate change; density; flash flood; geological record; hypersaline environment; lake level; plume; salinity; sediment transport; stratigraphy; turbidite, Dead Sea https://www.scopus.com/inward/record.uri?eid=2-s2.0-85134696043&doi=10.1016%2fj.epsl.2022.117723&partnerID=40&md5=88c5f0404460bae8eeaca46c16e6c0c8 cited By 1 Y. Lu E.L. Pope J. Moernaut R. Bookman N. Waldmann A. Agnon S. Marco M. Strasser article grambling2022thermal We investigate the cooling histories of peridotites and gabbros from localities that expose oceanic lithosphere formed beneath two fast seafloor spreading centers: Hess Deep as recovered from IODP Expedition 345 and ODP Leg 147, and the Oman Ophiolite as sampled by the Oman Drilling Project, ICDP Expedition 5057 (OmanDP). At these locations, relict crust-mantle transition zones are directly sampled, enabling characterization of the thermal history of the crust-mantle transition, and by inference, the depth extent of hydrothermal circulation beneath spreading centers. We measured major and trace element abundances in crustal gabbros and mantle peridotites from Hess Deep and OmanDP, and applied major and trace element-based thermometers. Geospeedometric interpretation of the temperatures suggests similar cooling histories at both locations; cooling rates ranged from 0.02 to 2.6 °C/y from peak temperatures up to 1,350°C. The rates are consistent on either side of the paleo-Moho (i.e., in the crust and mantle). Models for conductive cooling of the lower oceanic crust predict rates more than two orders of magnitude slower at the crust-mantle transition zone, while thermal models that invoke deep and efficient hydrothermal circulation throughout the entire crustal section predict rates consistent with our observations. We infer that hydrothermal cooling extended to or near the petrologic Moho beneath the East Pacific Rise and the OmanDP paleo-spreading center, consistent with the Sheeted Sills model for crustal accretion. Comparison with previously published rates recalculated using the methods we employed suggests the oceanic lower crust is cooled hydrothermally in some places and by conduction at others. © 2021. American Geophysical Union. All Rights Reserved. 2022 English 21699313 10.1029/2021JB022696 Journal of Geophysical Research: Solid Earth 127 Wiley Online Library e2021JB022696 Department of Earth and Planetary Sciences, University of Tennessee, Knoxville, TN, United States; Department of Geological Sciences, University of Texas at Austin, Austin, TX, United States; Department of Earth, Environmental and Planetary Sciences, Brown University, Providence, RI, United States; Leibniz Universität Hannover, Institut für Mineralogie, Hannover, Germany; Western Colorado University, Gunnison, CO, United States; Lamont Doherty Earth Observatory, Columbia University, New York, NY, United States 1 gabbro; hydrothermal alteration; mantle source; ophiolite; seafloor spreading; temperature anomaly; thermometry; trace element, East Pacific Rise; Hess Deep; Pacific Ocean https://www.scopus.com/inward/record.uri?eid=2-s2.0-85124075477&doi=10.1029%2f2021JB022696&partnerID=40&md5=29ba2009a0cf81bb0211776533045cf9 cited By 3 Nadine L Grambling Nicholas Dygert Beau Boring Marlon M Jean Peter B Kelemen article Fones2022 Article 2022 10.1111/1462-2920.16041 Environmental Microbiology https://www.scopus.com/inward/record.uri?eid=2-s2.0-85130352571&doi=10.1111%2f1462-2920.16041&partnerID=40&md5=74cc74bc6c69d5336b2a8539cf66a73b Cited by: 7 Elizabeth M. Fones Alexis S. Templeton David W. Mogk Eric S. Boyd article Wu2022 Article 2022 10.1016/j.cretres.2022.105193 Cretaceous Research 135 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85128187323&doi=10.1016%2fj.cretres.2022.105193&partnerID=40&md5=e583a0b2a38caea5e31a4ec4bc766025 Cited by: 1 Yixiao Wu Jianguo Li Miaoqin Lin Eva Koppelhus article Lozano-García2022 A new detailed pollen record of the penultimate glacial–interglacial–glacial cycle corresponding to the late marine isotopic stages (MISs) 6–3 (146–35 ka ago) has been obtained from Lake Chalco, in the Basin of Mexico. This record provides an insight into vegetation dynamics and climate variability at the northern limit of the American tropics. The pollen record displays a high temporal resolution with a mean sampling interval of ∼230 years. The changes in plant composition were reconstructed by pollen analysis and differences in plant composition between distinct periods were established. The wettest cold stage, indicated by a combination of diverse open vegetation and mesophytic taxa correlates with the penultimate late glacial MIS 6 (146–130 ka), when Lake Chalco was a deep freshwater lake. The penultimate interglacial MIS 5e (126.5–123.6 ka) shows a dominance of Pinus forests, with tropical taxa suggesting warmer than present conditions; environmental proxies indicate drier conditions and that the lake transitioned into a saline water body. Open communities and Pinus and Quercus forests with mesophytic taxa and, during the stadial periods, MIS 5 d, 5c, and 5 b (125–90 ka), with tropical taxa, characterize the record of interstadials. Pinus-dominated forests characterize the landscape during MIS 5a. MIS 5c to MIS 3 showed lower and variable evenness and palynological richness, along with an increase in fire activity. During MIS 4 and 3, a trend towards drier conditions was also recorded with enhanced carbonate precipitation and proxies indicating saline conditions. Tree-line changes in response to climate change and taxa migration were documented. A comparison with long records from the Greenland ice cores, the marine Cariaco Basin and insolation parameters revealed that the pollen data and the Pinus pollen accumulation rates evidence the response of the vegetation to glacial and interglacial changes and to millennial-scale variability. Wetter conditions were inferred to exist during the Greenland interstadials, while drier conditions persisted during Heinrich events. © 2022 Elsevier Ltd 2022 English 02773791 10.1016/j.quascirev.2022.107830 Quaternary Science Reviews 297 Elsevier Ltd Universidad Nacional Autónoma de México, Instituto de Geología, Ciudad de México, 04510, Mexico; Universidad de Guadalajara, Centro Universitario de La Costa Sur, Jalisco48900, Mexico; Universidad Nacional Autónoma de México, Instituto de Geofísica, Ciudad de México, 04510, Mexico Forestry; Glacial geology; Lakes; Saline water; Tropics; Vegetation, Basin of mexico; Dry condition; Last glacial; Marine isotopic stages; Me-xico; Millennial-scale variability; Penultimate interglacial; Plant diversity; Pollen analysis; Vegetation dynamics, Climate change, climate change; climate variation; coniferous forest; glacial-interglacial cycle; Last Glacial; late glacial; marine isotope stage; Neotropical Region; palynology; reconstruction; vegetation dynamics; vegetation history, Arctic; Atlantic Ocean; Cariaco Basin; Caribbean Sea; Greenland; Lake Chalco; Mexico [North America]; Valley of Mexico https://www.scopus.com/inward/record.uri?eid=2-s2.0-85140807059&doi=10.1016%2fj.quascirev.2022.107830&partnerID=40&md5=f131b185af7806968c279ca3020e137e cited By 1 S. Lozano-García E. Torres-Rodríguez B. Figueroa-Rangel M. Caballero S. Sosa-Nájera B. Ortega-Guerrero C. Acosta-Noriega article Lipus2024 Article 2022 10.33799/jokull2021.72.021 Jökull 72 21-34 S. Sayyadi M. T. Gudmundsson P. Einarsson article 2022 10.25131/geobulletin.65.1 Geobulletin 65 18-21 Christoph Heubeck Nick Beukes BASE Onsite Geoscience Team article Yabe20221679 In December 2007, an Mw2.2 earthquake occurred in a gabbroic dike at 3.3 km depth in a deep gold mine in South Africa. The fore- and aftershock activity was analyzed in an effort to understand the preparation and generation processes of earthquakes; these findings have already been published. The present paper focuses on the stress state in the source region of the mainshock. A 90-m-long borehole across the mainshock fault was drilled ~ 1.5 years after the mainshock and logged by an optical televiewer. The fault can be identified by severe damage to the borehole wall at the point where the borehole intersected the aftershock cluster. Except for a 10-m section in the hanging wall of the fault, borehole cores were fully recovered. Borehole breakout (BO) and core disking (CD) were found to occur. Two stress measurement techniques [Deformation Rate Analysis (DRA) and Diametrical Core Deformation Analysis (DCDA)] were applied to the borehole cores. By combining their results with occurrence criteria for BO and CD, the principal stress state in the source region of the mainshock was determined. The principal directions in the hanging wall of the fault were nearly identical to the virgin stress state, while it was significantly disturbed in the footwall. The vertical stresses were 106 MPa and 40 MPa in the hanging wall and footwall, respectively. The significant difference in the vertical stress between the two sides of the fault can be explained by the stress redistribution associated with a nonuniform slip on a nonplanar fault. © 2022, The Author(s). 2022 English 00334553 10.1007/s00024-022-02999-w Pure and Applied Geophysics 179 Birkhauser 1679-1700 Research Center for Prediction of Earthquakes and Volcanic Eruptions, Graduate School of Science, Tohoku University, 6-6 Aramaki aza Aoba, Aoba-ku, Miyagi, Sendai, 980-8579, Japan; AngloGold Ashanti, Gauteng, South Africa; School of Mining Engineering, University of the Witwatersrand, Gauteng, Johannesburg, South Africa; College of Science and Engineering, Ritsumeikan University, Shiga, Kusatsu, Japan; Institute of Fluid Science, Tohoku University, Miyagi, Sendai, Japan; Fukada Geological Institute, Tokyo, Japan; Earthquake Research Institute, The University of Tokyo, Tokyo, Japan; Disaster Prevention Research Institute, Kyoto University, Kyoto, Uji, Japan; School of Geoscience, University of the Witwatersrand, Johannesburg, South Africa; Kokusai Kogyo Co., Ltd, Chiyoda, Tokyo, Japan; SibanyeStillwater, Carletonville, South Africa; Rock Mechanics Laboratory CC, Gauteng, Johannesburg, South Africa 5 Deformation; Earthquakes; Faulting; Gold mines; Infill drilling, Deep mine in south africa; Deep-mines; Deformation analysis; Deformation rate analyse; Deformation rate analysis; Diametrical core deformation analyse; Drilling intersecting a seismogenic fault; Earthquake source; Seismogenic faults; Source region; South Africa; Stress in earthquake source region, Boreholes, aftershock; borehole stability; deformation mechanism; drilling; earthquake event; earthquake magnitude; gabbro; gold mine, South Africa https://www.scopus.com/inward/record.uri?eid=2-s2.0-85127564479&doi=10.1007%2fs00024-022-02999-w&partnerID=40&md5=7d37fad5df28e36d30386f2b78c4917d cited By 0 Y. Yabe S. Abe G. Hofmann D. Roberts H. Yilmaz H. Ogasawara T. Ito A. Funato M. Nakatani M. Naoi article Rospabé202275 The Oman Drilling Project (OmanDP), performed under the International Continental Scientific Drilling Program (ICDP), is an international scientific research project that undertook drilling at a range of sites in the Semail ophiolite (Oman) to collect core samples spanning the stratigraphy of the ophiolite, from the upper oceanic crust down to the basal thrust. The cores were logged to International Ocean Discovery Program (IODP) standards aboard the D/V Chikyu. During ChikyuOman2018 Leg 3 (July-August 2018), participants described cores from the crust-mantle transition (CM) sites. The main rock types recovered at these sites were gabbros, dunites and harzburgites, rocks typically forming the base of the oceanic crust and the shallow mantle beneath present-day spreading centres. In addition to the core description, selected samples were analysed by X-ray fluorescence spectrometry (XRF) for their chemical compositions, including major, minor and some trace elements. To complement these standard procedures, we developed new approaches to measure ultra-trace element concentrations using a procedure adapted from previous works to prepare fine-grained pressed powder pellets coupled with laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS) analysis using instrumentation aboard the D/V Chikyu. First, three (ultra)mafic reference materials were investigated to test and validate our procedure (BHVO-2, BIR-1a and JP-1), and then the procedure was applied to a selection of gabbro and dunite samples from the CM cores to explore the limitations of the method in its current stage of development. The obtained results are in good agreement with preferred values for the reference materials and with subsequent solution replicate analyses of the same samples performed in shore-based laboratories following Leg 3 for the CM samples. We describe this procedure for the determination of 37 minor and (ultra-)trace elements (transition elements and Ga, Li and Large-Ion Lithophile Elements (LILE), Rare Earth Elements (REE), High-Field-Strength Elements (HFSE), U, Th, and Pb) in mafic and ultramafic rocks. The presented method has the major advantage that it allows the determination at sea of the (ultra-)trace element concentrations in a "dry", safe way, without using acid reagents. Our new approach could be extended for other elements of interest and/or be improved to be adapted to other rock materials during future ocean drilling operations aboard the D/V Chikyu and other platforms. © 2022 Mathieu Rospabé et al. 2022 English 18168957 10.5194/sd-30-75-2022 Scientific Drilling 30 Copernicus GmbH 75-99 Research Institute for Marine Geodynamics (IMG), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima, Kanagawa, Yokosuka, 237-0061, Japan; Géosciences Environnement Toulouse (GET), Observatoire Midi-Pyrénées, Université de Toulouse, CNRS, IRD, 14 avenue E. Belin, Toulouse, 31400, France; Institute of Earth Sciences, Academia Sinica, Academia Road, Nangang, Taipei, 11529, Taiwan; Department of Sciences, College of Science and Engineering, Kanazawa University, Kanazawa, Ishikawa, 920-1192, Japan; Department of Geology, Faculty of Science, Niigata University, Niigata, Niigata, 950-2181, Japan; Instituto Andaluz de Ciencias de la Tierra (IACT), Consejo Superior de Investigaciones Científicas-Universidad de Granada, Avd. Palmeras 4, Armilla, Granada, 18100, Spain; School of Ocean and Earth Science, National Oceanography Centre Southampton, University of Southampton, European Way, Southampton, SO14-3ZH, United Kingdom; Géosciences Montpellier, CNRS, Université Montpellier, Place E. Bataillon, Montpellier, 34095, France; Department of Geology, Trinity College Dublin, Dublin 2, Ireland; Mantle Drilling Promotion Office, Institute for Marine-Earth Exploration and Engineering (MarE3), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 3173-25 Showa-machi, Kanazawa-ku, Kanagawa, Yokohama, 236-0001, Japan; Institute for Marine-Earth Exploration and Engineering (MarE3), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima, Kanagawa, Yokosuka, 237-0061, Japan Exploratory geochemistry; Fluorescence spectroscopy; Inductively coupled plasma; Inductively coupled plasma mass spectrometry; Infill drilling; Laser ablation; Pelletizing; Petrology; Preferred numbers; Rare earths; Rocks; Stratigraphy, Crust mantle; Drilling projects; Laser-ablation inductively-coupled plasma mass spectrometry; Mass spectrometry analysis; New approaches; Oceanic crust; Pressed powder pellets; Trace elements concentration; Traces elements; Ultratraces, Trace elements https://www.scopus.com/inward/record.uri?eid=2-s2.0-85125994511&doi=10.5194%2fsd-30-75-2022&partnerID=40&md5=315c7ac77a0fde9f666b4d46f0825e9e cited By 1 M. Rospabé F. Kourim A. Tamura E. Takazawa M. Giampouras S. Chatterjee K. Ishii M.J. Cooper M. Godard E. Carter N. Abe K. Moe D.A.H. Teagle Oman Drilling Project "ChikyuOman2018 Leg 3"Science Team article Menzel20221191 The reaction of serpentinized peridotite with CO2-bearing fluids to form listvenite (quartz-carbonate rock) requires massive fluid flux and significant permeability despite an increase in solid volume. Listvenite and serpentinite samples from Hole BT1B of the Oman Drilling Project help to understand mechanisms and feedbacks during vein formation in this process. Samples analyzed in this study contain abundant magnesite veins in closely spaced, parallel sets and younger quartz-rich veins. Cross-cutting relationships suggest that antitaxial, zoned magnesite veins with elongated grains growing from a median zone towards the wall rock are among the earliest structures to form during carbonation of serpentinite. Their bisymmetric chemical zoning of variable Ca and Fe contents, a systematic distribution of SiO2 and Fe-oxide inclusions in these zones, and cross-cutting relations with Fe oxides and Cr spinel indicate that they record progress of reaction fronts during replacement of serpentine by carbonate in addition to dilatant vein growth. Euhedral terminations and growth textures of magnesite vein fill, together with local dolomite precipitation and voids along the vein-wall rock interface, suggest that these veins acted as preferred fluid pathways allowing infiltration of CO2-rich fluids necessary for carbonation to progress. Fracturing and fluid flow were probably further enabled by external tectonic stress, as indicated by closely spaced sets of subparallel carbonate veins. Despite widespread subsequent quartz mineralization in the rock matrix and veins, which most likely caused a reduction in the permeability network, carbonation proceeded to completion within listvenite horizons. © 2022 Manuel D. Menzel et al. 2022 English 18699510 10.5194/se-13-1191-2022 Solid Earth 13 Copernicus GmbH 1191-1218 Tectonics and Geodynamics, RWTH Aachen University, Lochnerstrasse 4-20, Aachen, 52056, Germany; Bureau of Economic Geology, The University of Texas at Austin, Austin, TX, United States; Géosciences Montpellier, CNRS, Université de Montpellier, Montpellier, France 8 Carbon dioxide; Flow of fluids; Iron oxides; Magnesia; Magnesite; Mineralogy; Quartz; Rocks; Serpentine; Textures, Carbonate rock; Cross-cutting; Drilling projects; Fe oxide; Fluid fluxes; Quartz + carbonates; Serpentinite; Serpentinized peridotites; Solid volumes; Vein formation, Carbonation, mineralization; ophiolite; peridotite; quartz; serpentinite; serpentinization; zoning, Oman https://www.scopus.com/inward/record.uri?eid=2-s2.0-85135632552&doi=10.5194%2fse-13-1191-2022&partnerID=40&md5=4f073b16e5b5b17664442b223bf829d4 cited By 0 M.D. Menzel J.L. Urai E. Ukar T. Decrausaz M. Godard article Zheng20222075 Well Songke−2 is the main hole of the Continental Scientific Drilling Project of Songliao Basin, China, and its bottom hole temperature is estimated to exceed 240°C in the fourth spud at the well depth of 5800 m. To ensure that the drilling fluid could meet the demand of high temperature resistance, different components, including clay, filtration reducers and anti−collapse additives, of the high–temperature drilling fluid system were optimized through thermal stability tests. Comprehensive test results suggested that the optimal bentonite content to be 4% (w/v). Compared with other materials of the same type, polymer filtration reducers SO−1 and HLW−1, as well as sulfonation additive LOCKSEAL were demonstrated to have stronger resistance to high temperature. The proposed high temperature drilling fluid formula exhibited good thermal stability, rheological behaviour, anti−contamination capacity and shale inhibition property. Finally, a great success of the formula was practically obtained in the field application during the following−up core drilling project. © 2022 Taylor & Francis Group, LLC. 2022 English 15567036 10.1080/15567036.2019.1649323 Energy Sources, Part A: Recovery, Utilization and Environmental Effects 44 Taylor and Francis Ltd. 2075-2087 School of Engineering, China University of Geosciences (Wuhan, Wuhan, China; College of Geoscience and Surveying Engineering, China University of Mining Technology (Beijing), Beijing, China 1 Additives; Bentonite; Drilling fluids; Infill drilling; Thermodynamic stability, Bottom hole temperatures; Continental scientific drillings; Drilling fluid systems; High temperature resistance; High temperature stability; Research and application; Rheological behaviour; Songliao basin, Core drilling https://www.scopus.com/inward/record.uri?eid=2-s2.0-85070465069&doi=10.1080%2f15567036.2019.1649323&partnerID=40&md5=b500da8a21f4dacac58367f4da1f368b cited By 3 W. Zheng X. Wu Y. Huang article Lei20222273 Natural gas hydrate (NGH) is a clean and efficient energy resource with extensive distribution in the permafrost regions and marine sediments. A few short-term production tests focusing on reservoir depressurization have been conducted in recent years. However, the long-term production performance and the transient evolution characteristics of reservoir properties are not well known. In this work, a more realistic hydrate-reservoir model that considers the heterogeneity of permeability, porosity and hydrate saturation is constructed, according to the available geological data at the Mallik site. The model is validated by reproducing the field depressurization test. The main purposes of this work are to evaluate the long-term gas production performance and to analyze the unique multiphase flow behaviors from the validated geologically descriptive hydrate-reservoir model. The results indicate that the long-term gas production through depressurization from hydrate reservoirs at the Mallik site is technically feasible, but the gas production efficiency is generally modest. The hydrate dissociation front in HBS is strongly affected by the reservoir heterogeneity and shows a unique dissociation front. The vertically heterogeneous HBS is beneficial for depressurization production compared to the massive hydrate reservoirs. Furthermore, the vertically heterogeneous hydrate-reservoir with low permeability of clay-layer can effectively block methane gas diffusion in the vertical direction. These emphasize that constructing realistic reservoir models is very important to accurately predict the hydrate production performance. At the end of 1-year depressurization, a total of 1.80 × 106 ST m3 of methane gas can be produced from the validated hydrate-reservoir, while which is far from the commercial value. In addition, reducing the production pressure in the wellbore is beneficial for increasing gas production volume, but is not conducive to improving the hydrate production efficiency at the Mallik site. © 2022 The Author(s) 2022 English 23524847 10.1016/j.egyr.2022.01.170 Energy Reports 8 Elsevier Ltd 2273-2287 State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan, 430071, China; Hubei Key Laboratory of Geotechnical and Structural Engineering Safety, School of Civil Engineering, Wuhan University, Wuhan 430072, Hubei, China; Key Laboratory of Groundwater Resources and Environment, Ministry of Education, Jilin University, Changchun, 130021, China; Engineering Research Center of Geothermal Resources Development Technology and Equipment, Ministry of Education, Jilin University, Changchun, 130026, China Dissociation; Energy resources; Gases; Hydration; Methane; Natural gas; Natural gas deposits; Petroleum reservoir engineering; Petroleum reservoirs; Submarine geology, Depressurizations; Gas productions; Heterogeneous; Mallik site; Methane gas; Natural gas hydrates; Natural gas-hydrates; Production efficiency; Production performance; Reservoir models, Gas hydrates https://www.scopus.com/inward/record.uri?eid=2-s2.0-85123882564&doi=10.1016%2fj.egyr.2022.01.170&partnerID=40&md5=39876b06a9580d06301a0353839b60a2 cited By 5 H. Lei Z. Yang Y. Xia Y. Yuan article Fu20222346 Well SK-2 is located in the Songliao Basin. Core samples from this well indicate that the Early Cretaceous Shahezi Formation has a length of 2,359.01 m and is in direct contact with the basin basement of the Middle Triassic, missing the Huoshiling Formation. This paper is focused on the lowest sequence 1 (S1, at the bottom of the Shahezi Formation, interval of 5,450.72–5,695.00 m, a length of 244.28 m) of the Cretaceous basin fills. It was found that the volcanic components contributed important parts in the sequence of basin fills, and the start of the rifting resulted from the combination of regional extensional tectonics and volcanism. Based on the centimetre-scale description of the continuous core samples, we propose a model to delineate the interaction between tectonics, volcanism, and pyroclastic deposition. The study shows the tectonic-volcanism in the earliest rifting stages and its control on sedimentary filling. These results also have common sense for the initial rifting process of a continental half-graben basin. Sequence 1 of the Shahezi Formation in well SK-2 shows a typical volcanic- sedimentary sequence. During the lowstand stage, the weathering-depositional system was controlled by extension; during the transgressive and highstand stages, the transitional weathering-depositional system and the mixed volcanic and weathering depositional system were controlled by transtension. © 2022 John Wiley & Sons Ltd. 2022 English 00721050 10.1002/gj.4414 Geological Journal 57 John Wiley and Sons Ltd 2346-2364 College of Earth Sciences, Jilin University, Changchun, China; Key Laboratory of Mineral Resources Evaluation in Northeast Asia, Ministry of Natural Resources, Changchun, China; Paleontology and Stratigraphy Research Center, Jilin University, Changchun, China 6 Cretaceous; graben; lithofacies; provenance; pyroclastic deposit; tectonics; transtension; Triassic; volcanism; weathering, China; Songliao Basin https://www.scopus.com/inward/record.uri?eid=2-s2.0-85124623900&doi=10.1002%2fgj.4414&partnerID=40&md5=ad23605e91a2335352c46729ad54a20f cited By 1 Y. Fu R. Cheng Y. Gao Y. Zhou Z. Xu article Zhao2022915 The 3.6-Myr sedimentary record of Lake El'gygytgyn is crucial for understanding the response of the sensitive ecosystems in the Arctic to Quaternary climate variations at orbital timescales. In this study, we synthesize previously published pollen records and biome reconstructions and perform pollen diversity analysis of the deep-drilling core ICDP 5011-1 from Lake El'gygytgyn for periods during the Early Pleistocene (MIS 82 – MIS 79), Early–Middle Pleistocene (MIS 31 – MIS 18) and late Middle Pleistocene (MIS 7e – MIS 6f). The results indicate that the predominance of herb tundra in the regional vegetation was most characteristic during glacials/stadials. Interglacials, in contrast, can be distinguished by the expansion of shrub communities mainly composed of birch, alder and willow. The expansion of forest biomes in the region was influenced by peaks in obliquity values, which led to increases in daylight length, which was essential for plant growth in high latitudes. An apparent long-term decreasing trend in the tree and shrub population, accompanied by a reduction in floristic richness, was induced by stepwise cooling and drying since the Mid-Pleistocene Transition (MPT), which is linked to the modulation of extended global ice volume during the MPT via strong snow- and ice-albedo feedback effects. © 2022 John Wiley & Sons, Ltd. 2022 English 02678179 10.1002/jqs.3408 Journal of Quaternary Science 37 John Wiley and Sons Ltd 915-927 School of Geographic Science, Nantong University, Nantong, 226007, China; Alfred Wegener Institute Helmholtz Center for Polar and Marine Research, Research Unit Potsdam, Potsdam, 14473, Germany; Kazan Federal University, Kazan, 420018, Russian Federation; Institute of Geology and Mineralogy, University of Cologne, Cologne, 50674, Germany; Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, China; University of the Chinese Academy of Sciences, Beijing, 100049, China 5 albedo; environmental change; glacial-interglacial cycle; ice; Milankovitch cycle; Pleistocene; pollen; snow; vegetation, Chukchi; Elgygytgyn Lake; Russian Federation https://www.scopus.com/inward/record.uri?eid=2-s2.0-85122734106&doi=10.1002%2fjqs.3408&partnerID=40&md5=e2bd9418f0d524a13e17bcb0f6c2e32a cited By 1 W. Zhao A.A. Andreev V. Wennrich Q. Li M. Melles article Cohen2022451 Paleoanthropologists have long speculated about the role of environmental change in shaping human evolution in Africa. In recent years, drill cores of late Neogene lacustrine sedimentary rocks have yielded valuable high-resolution records of climatic and ecosystem change. Eastern African Rift sediments (primarily lake beds) provide an extraordinary range of data in close proximity to important fossil hominin and archaeological sites, allowing critical study of hypotheses that connect environmental history and hominin evolution. We review recent drill-core studies spanning the Plio-Pleistocene boundary (an interval of hominin diversification, including the earliest members of our genus Homo and the oldest stone tools), and the Mid-Upper Pleistocene (spanning the origin of Homo sapiens in Africa and our early technological and dispersal history). Proposed drilling of Africa's oldest lakes promises to extend such records back to the late Miocene. squf High-resolution paleoenvironmental records are critical for understanding external drivers of human evolution. squf African lake basin drill cores play a critical role in enhancing hominin paleoenvironmental records given their continuity and proximity to key paleoanthropological sites. squf The oldest African lakes have the potential to reveal a comprehensive paleoenvironmental context for the entire late Neogene history of hominin evolution. © 2022 by Annual Reviews. All rights reserved. Review 2022 English 00846597 10.1146/annurev-earth-031920-081947 Annual Review of Earth and Planetary Sciences 50 Annual Reviews Inc. 451 – 476 Africa; Core drilling; Drills; Infill drilling; Sedimentary rocks; Stratigraphy; Continental scientific drillings; Drill core; East African Rift; Eastern Africa; Environmental contexts; High resolution; Hominins; Human evolution; Late Neogene; Paleoclimates; environmental change; environmental history; human evolution; Neogene; paleoclimate; Pleistocene; Lakes https://www.scopus.com/inward/record.uri?eid=2-s2.0-85128712352&doi=10.1146%2fannurev-earth-031920-081947&partnerID=40&md5=90ef154d59093a09e28aa29a9a3cf030 Cited by: 2 Andrew S. Cohen Christopher J. Campisano J. Ramo acute n Arrowsmith Asfawossen Asrat Catherine C. Beck Anna K. Behrensmeyer Alan L. Deino Craig S. Feibel Verena Foerster John D. Kingston Henry F. Lamb Tim K. Lowenstein Rachel L. Lupien Veronica Muiruri Daniel O. Olago R. Bernhart Owen Richard Potts James M. Russell Frank Schaebitz Jeffery R. Stone Martin H. Trauth Chad L. Yost article Cohen2022451 Review 2022 10.1146/annurev-earth-031920-081947 Annual Review of Earth and Planetary Sciences 50 451 – 476 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85128712352&doi=10.1146%2fannurev-earth-031920-081947&partnerID=40&md5=90ef154d59093a09e28aa29a9a3cf030 Cited by: 10; All Open Access, Bronze Open Access Andrew S. Cohen Christopher J. Campisano J. Ramo acute n Arrowsmith Asfawossen Asrat Catherine C. Beck Anna K. Behrensmeyer Alan L. Deino Craig S. Feibel Verena Foerster John D. Kingston Henry F. Lamb Tim K. Lowenstein Rachel L. Lupien Veronica Muiruri Daniel O. Olago R. Bernhart Owen Richard Potts James M. Russell Frank Schaebitz Jeffery R. Stone Martin H. Trauth Chad L. Yost article WOS:000911968500013 2022 10.1126/sciadv.abo0866 SCIENCE ADVANCES 8 Micha Ruhl Stephen P. Hesselbo Hugh C. Jenkyns Weimu Xu Ricardo L. Silva Kara J. Matthews Tamsin A. Mather Conall Mac Niocaill James B. Riding article Wu2022992 The bottom simulating reflection (BSR) characteristics of reflected seismic waves are an important sign of gas hydrate. Although they can indicate the bottom of hydrate, they can hardly be used for quantitative interpretation of hydrate content. The rapid development of the gas hydrate exploration technology in recent years results in an understanding that the "blank" zone of seismic amplitude above BSR, directly related to the absorption and attenuation of seismic waves, can be used as an indicator of gas hydrate distribution and quantification. This paper reviews the seismic wave absorption and attenuation characteristics of various hydrate exploration areas around the world (the Mallik permafrost area in Canada, the Nankai Trough in Japan, the Makran accretionary wedge in the Arabian Sea, the Gulf of Mexico, and the Shenhu area in the South China Sea) and artificial hydrate-bearing rock samples. The results show that for different hydrate exploration areas, hydrate-bearing samples, and data used, seismic waves show different attenuation characteristics. Then, the possible attenuation mechanisms and related petrophysical theories are summarized for hydrate reservoirs, mainly including global flow attenuation (the Leclaire model), squirt flow (the improved Leclaire model, the hydrate effective grain (HEG) model for submicron hydrate particle squirt, or the hydrate-bearing effective sediment (HBES) model for micron flow squirt), skeleton friction attenuation (the improved Leclaire model). At present, the main problem is that although the hydrate-bearing strata in many areas demonstrate obvious absorption and attenuation characteristics, the relationships of absorption and attenuation variation with hydrate saturation remain unknown due to the varied hydrate formation conditions and geological environments and different occurrence states of hydrate in sediments of different areas. In addition, the frequency band ranges of the current measured observation data and those petrophysical experiments test are limited, so the characteristics of attenuation variation with frequency are not fully reflected. Therefore, petrophysical experimental studies need to be further conducted, and available data from actual exploration areas and the making and experimental measurement results of artificial cores shall be well utilized, thereby studying the additional effect of the microstructure of the hydrate reservoir on the attenuation mechanism in depth. After the reasons of seismic wave attenuation in hydrate reservoirs are clarified, a quantitative seismic interpretation method for hydrate saturation can be developed. © 2022, Editorial Department OIL GEOPHYSICAL PROSPECTING. All right reserved. 2022 Chinese 10007210 10.13810/j.cnki.issn.1000-7210.2022.04.026 Shiyou Diqiu Wuli Kantan/Oil Geophysical Prospecting 57 Science Press 992-1008 College of Geophysics, China University of Petroleum (Beijing), Beijing, 102249, China 4 Gas hydrates; Gases; Hydration; Microstructure; Petroleum prospecting; Petrophysics; Seismology, Attenuation characteristics; Bottom simulating reflection; Exploration technologies; Gas hydrate reservoir; Hydrate saturation; Petrophysical; Petrophysics; Quantitative interpretation; Reflection characteristics; Seismic attenuation, Seismic waves https://www.scopus.com/inward/record.uri?eid=2-s2.0-85134836876&doi=10.13810%2fj.cnki.issn.1000-7210.2022.04.026&partnerID=40&md5=c2b503cd18422ad74561eea149cc1975 cited By 0 C. Wu F. Zhang X. Li article patterson2022sensitivity 2022 Scientific Drilling 30 Copernicus GmbH 101--112 Molly O Patterson Richard H Levy Denise K Kulhanek Tina Flierdt Huw Horgan Gavin B Dunbar Timothy R Naish Jeanine Ash Darcy Mandeno others article Déhais2022 This work presents isotopic data for the non-traditional isotope systems Fe, Cu, and Zn on a set of Chicxulub impactites and target lithologies with the aim of better documenting the dynamic processes taking place during hypervelocity impact events, as well as those affecting impact structures during the post-impact phase. The focus lies on material from the recent IODP-ICDP Expedition 364 Hole M0077A drill core obtained from the offshore Chicxulub peak ring. Two ejecta blanket samples from the UNAM 5 and 7 cores were used to compare the crater lithologies with those outside of the impact structure. The datasets of bulk Fe, Cu, and Zn isotope ratios are coupled with petrographic observations and bulk major and trace element compositions to disentangle equilibrium isotope fractionation effects from kinetic processes. The observed Fe and Cu isotopic signatures, with δ56/54Fe ranging from −0.95‰ to 0.58‰ and δ65/63Cu from −0.73‰ to 0.14‰, mostly reflect felsic, mafic, and carbonate target lithology mixing and secondary sulfide mineral formation, the latter associated to the extensive and long-lived (&gt;105 years) hydrothermal system within Chicxulub structure. On the other hand, the stable Zn isotope ratios provide evidence for volatility-governed isotopic fractionation. The heavier Zn isotopic compositions observed for the uppermost part of the impactite sequence and a metamorphic clast (δ66/64Zn of up to 0.80‰ and 0.87‰, respectively) relative to most basement lithologies and impact melt rock units indicate partial vaporization of Zn, comparable to what has been observed for Cretaceous-Paleogene boundary layer sediments around the world, as well as for tektites from various strewn fields. In contrast to previous work, our data indicate that an isotopically light Zn reservoir (δ66/64Zn down to −0.49‰), of which the existence has previously been suggested based on mass balance considerations, may reside within the upper impact melt rock (UIM) unit. This observation is restricted to a few UIM samples only and cannot be extended to other target or impact melt rock units. Light isotopic signatures of moderately volatile elements in tektites and microtektites have previously been linked to (back-)condensation under distinct kinetic regimes. Although some of the signatures observed may have been partially overprinted during post-impact processes, our bulk data confirm impact volatilization and condensation of Zn, which may be even more pronounced at the microscale, with variable degrees of mixing between isotopically distinct reservoirs, not only at proximal to distal ejecta sites, but also within the lithologies associated with the Chicxulub impact crater. © 2022 China University of Geosciences (Beijing) and Peking University 2022 10.1016/j.gsf.2022.101410 Geoscience Frontiers 13 Analytical, Environmental and Geo-Chemistry, Vrije Universiteit Brussel, Brussels, Belgium; Laboratoire G-Time, Université Libre de Bruxelles, Brussels, Belgium; Department of Chemistry, Atomic & Mass Spectrometry, Ghent University, Ghent, Belgium 5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85131909400&doi=10.1016%2fj.gsf.2022.101410&partnerID=40&md5=a7de8ed71f6bbaf59e490315722ee5de cited By 0 T. Déhais S.M. Chernonozhkin P. Kaskes S.J. Graaff V. Debaille F. Vanhaecke P. Claeys S. Goderis article Tian20223543 Article 2022 10.3799/dqkx.2022.248 Diqiu Kexue - Zhongguo Dizhi Daxue Xuebao/Earth Science - Journal of China University of Geosciences 47 3543 – 3568 10 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85141677454&doi=10.3799%2fdqkx.2022.248&partnerID=40&md5=7363bd8a45ecd6589ad50e46e8a722f6 Cited by: 17; All Open Access, Gold Open Access Jun Tian Huaichun Wu Chunju Huang Mingsong Li Chao Ma Pinxian Wang article bergsten2022rhodothermus 2022 10.1099/ijsem.0.005214 International Journal of Systematic and Evolutionary Microbiology 72 Microbiology Society 005214 1 Pauline Bergsten Pauline Vannier Alan Mougeolle Louise Rigaud Viggó Thór Marteinsson article Feignon202274 Constraining the degree of preservation of a meteoritic signature within an impact structure provides vital insights in the complex pathways and processes that occur during and after an impact cratering event, providing information on the fate of the projectile. The IODP-ICDP Expedition 364 drilling recovered a ∼829 m continuous core (M0077A) of impactites and basement rocks within the ∼200-km diameter Chicxulub impact structure peak ring. No highly siderophile element (HSE) data have been reported for any of the impact melt rocks of this drill core to date. Previous work has shown that most Chicxulub impactites contain less than 0.1% of a chondritic component. Only few impact melt rock samples in previous drill cores recovered from the Chicxulub might contain such a signal. Therefore, we analyzed impact melt rock and suevite samples, as well as pre-impact lithologies of the Chicxulub peak ring, with a focus on the HSE concentrations and Re–Os isotopic compositions. Similar to the concentrations of the other major and trace elements, those of the moderately siderophile elements (Cr, Co, Ni) of impact melt rock samples primarily reflect mixing between a mafic (dolerite) and felsic (granite) components, with the incorporation of carbonate material in the upper impact melt rock unit (from 715.60 to 747.02 meters below seafloor). The HSE concentrations of the impact melt rocks and suevites are generally low (&lt;39 ppt Ir, &lt;96 ppt Os, &lt;149 ppt Pt), comparable to the values of the average upper continental crust, yet three impact melt rock samples exhibit an enrichment in Os (125–410 ppt) and two of them also in Ir (250–324 ppt) by one order of magnitude relative to the other investigated samples. The 187Os/188Os ratios of the impact melt rocks are highly variable, ranging from 0.18 to 2.09, probably reflecting heterogenous target rock contributions to the impact melt rocks. The significant amount of mafic dolerite (mainly ∼20–60% and up to 80–90%), which is less radiogenic (187Os/188Os ratio of 0.17), within the impact melt rocks makes an unambiguous identification of an extraterrestrial admixture challenging. Granite samples have unusually low 187Os/188Os ratios (0.16 on average), while impact melt rocks and suevites broadly follow a mixing trend between upper continental crust and chondritic/mantle material. Only one of the investigated samples of the upper impact melt rock unit could also be interpreted in terms of a highly diluted (∼0.01–0.05%) meteoritic component. Importantly, the impact melt rocks and pre-impact lithologies were affected by post-impact hydrothermal alteration processes, probably remobilizing Re and Os. The mafic contribution, explaining the least radiogenic 187Os/188Os values, is rather likely. The low amount of meteoritic material preserved within impactites of the Chicxulub impact structure may result from a combination of the assumed steeply-inclined trajectory of the Chicxulub impactor (enhanced vaporization, and incorporation of projectile material within the expansion plume), the impact velocity, and the volatile-rich target lithologies. © 2022 The Author(s) 2022 10.1016/j.gca.2022.02.006 Geochimica et Cosmochimica Acta 323 74-101 Department of Lithospheric Research, University of Vienna, Althanstrasse 14, Vienna, A-1090, Austria; Institute for Geology and Mineralogy, University of Cologne, Zülpicher Strasse 49b, Cologne, 50674, Germany; Natural History Museum, Burgring 7, Vienna, 1010, Austria; Research Unit: Analytical, Environmental & Geo-Chemistry, Department of Chemistry, Vrije Universiteit Brussel, AMGC-WE-VUB, Pleinlaan 2, Brussels, 1050, Belgium; Laboratoire G-Time, Université Libre de Bruxelles, Av. F.D. Roosevelt 50, Brussels, 1050, Belgium https://www.scopus.com/inward/record.uri?eid=2-s2.0-85125716964&doi=10.1016%2fj.gca.2022.02.006&partnerID=40&md5=bc1dea5f378ee1172610c64f5dc8a0e0 cited By 2 J.-G. Feignon T. Schulz L. Ferrière S. Goderis S.J. Graaff P. Kaskes T. Déhais P. Claeys C. Koeberl article Zawacki2022 Detrital zircons from two major rift basins within the East African Rift System (EARS) provide a means to evaluate not only sediment provenance and landscape dynamics in sedimentary basins, but also the timing of the silicic volcano-tectonic evolution of the rift system. We sampled from drill cores collected by the Hominin Sites and Paleolakes Drilling Project (HSPDP) in Ethiopia and Kenya to study the detrital mineral records of the Northern Awash (NA; 3.3–2.9 Ma) and West Turkana (WTK; 1.9–1.4 Ma) drill cores. We performed (U-Th)/He and U/Pb analyses on detrital zircons using single crystal laser ablation double dating (LADD) techniques. Analyses of four NA samples yielded zircon 206Pb/238U dates younger than ∼45 Ma, consistent with derivation from silicic volcanic rocks associated with EARS activity. Most of these samples lack zircon 206Pb/238U dates from ∼22–13 Ma, due to a decrease in silicic volcanism and a watershed configuration limiting delivery of silicic source materials to the sample site. NA zircon 206Pb/238U dates imply a sedimentary source from the western Afar margin, with a transition to more localized sediment reworking within the Afar Depression after a major regional tectonic reorganization and formation of a disconformity at ∼2.9 Ma. The WTK sample yielded many zircons with Cenozoic 206Pb/238U dates similar to those from the NA core, but the WTK sample also sources a small population of Neoproterozoic zircons associated with rocks from the Mozambique Belt and reworked sedimentary deposits. Despite being recorders of predominantly silicic activity, the detrital zircon U/Pb dates from both drill sites track the established timing of major volcanic phases in the EARS. A subset of zircons from both sites has concordant 206Pb/238U and (U-Th)/He dates, indicating a short duration between zircon crystallization and eruption of the host volcanic rock, but the majority of zircon (U-Th)/He dates are significantly younger than the 206Pb/238U dates for the same zircon. Some (U-Th)/He dates are even younger than the depositional age of the sedimentary sample from which it was collected. The observed spread in zircon (U-Th)/He dates likely reflects partial resetting associated with late mafic volcanism and/or hydrothermal activity within this dynamic rift environment. © 2022 Elsevier B.V. Article 2022 English 0012821X 10.1016/j.epsl.2022.117375 Earth and Planetary Science Letters 580 Elsevier B.V. East African Rift; Clay alteration; Core drilling; Drills; Infill drilling; Sedimentary rocks; Sedimentology; Single crystals; Tectonics; Volcanic rocks; Volcanoes; Zircon; Detrital zircon; Double dating; Drill core; East African Rift; Hydrothermal alterations; Laser ablation double dating; Lasers ablations; Rift systems; Sediment provenance; Tectonic evolution; dating method; detrital deposit; helium isotope; hydrothermal alteration; provenance; sediment analysis; tectonic evolution; uranium series dating; uranium-lead dating; zircon; Laser ablation https://www.scopus.com/inward/record.uri?eid=2-s2.0-85123289646&doi=10.1016%2fj.epsl.2022.117375&partnerID=40&md5=4d74590c037cc9a14bc3ded91554da64 Cited by: 2 Emily E. Zawacki Matthijs C. Soest Kip V. Hodges Jennifer J. Scott Mélanie Barboni Manfred R. Strecker Craig S. Feibel Christopher J. Campisano J. Ramón Arrowsmith article Yang20222080 For more extensive and efficient sea-level and lake-level reconstructions and correlations in siliciclastic systems, this paper presents a new tool called SediRate-Fischer plot (SR-Fischer plot). In SR-Fischer plots, the linear-corrected sedimentary rate of each terrigenous sedimentary cycle is plotted from the top of the previous cycle to the top of the current cycle. This process is repeated cycle by cycle, constructing curves of cumulative departure from mean sedimentary rate (CDMR). Based on the assumption that relative sea-level and lake-level changes may control sedimentary rates of subaqueous terrigenous sediments within basins, the CDMR could change inversely with relative sea or lake level. Thus, this tool could be interpreted as an indicator of relative sea-level and lake-level changes in terrigenous successions. SediRate-Fischer plots can be obtained from either lithological or proxy cycles formed by sea-level and lake-level changes in the case of availability of orbitally tuned data. The SR-Fischer plots constructed based on different materials are compared with other methods in two cases, as follows: first for the lacustrine Mingshui Formation of the Songliao Basin in China; and second for the deep-marine Arcillas de Gibraleón Formation of the Guadalquivir Basin in Spain. The SR-Fischer plots of the Mingshui Formation exhibit low and high CDMR values for shallow-lake intervals and lakeshore intervals, respectively, and vary inversely with the lake-level curves derived from changes in sedimentary facies. For the Arcillas de Gibraleón Formation, the CDMR values illustrated by the SR-Fischer plots exhibit opposite variations with sea-level curves indicated by dinocyst/pollen ratios. The negative Z-scores derived from runs tests indicate that these SR-Fischer plots are not randomly stacked and are minimally influenced by different cycle-splitting strategies. Thus, the results of comparison with other methods and runs tests demonstrate the validity of this method. Nonetheless, the other allogenic inflows (tectonics and climates) may limit interpretations of SR-Fischer plots. © 2022 International Association of Sedimentologists. Article 2022 English 00370746 10.1111/sed.12983 Sedimentology 69 John Wiley and Sons Inc 2080 – 2098 5 Andalucia; China; Guadalquivir Basin; Songliao Basin; Spain; Lakes; Lithology; Sea level; Fischer plot; Guadalquivir basin; Lake level changes; Lake levels; Orbital tuning; Relative sea level; Run test; Sedimentary cycles; Sedimentary rate; Songliao basin; facies; lake level; lithology; sea level change; terrigenous deposit; Sedimentology https://www.scopus.com/inward/record.uri?eid=2-s2.0-85127230939&doi=10.1111%2fsed.12983&partnerID=40&md5=af4e0826f2a19fcdea4231c6c0902f21 Cited by: 2 Daming Yang Yongjian Huang Chengshan Wang article Levy2022518 The hypersaline Dead Sea and its sediments are natural laboratories for studying extremophile microorganism habitat response to environmental change. In modern times, increased freshwater runoff to the lake surface waters resulted in stratification and dilution of the upper water column followed by microbial blooms. However, whether these events facilitated a microbial response in the deep lake and sediments is obscure. Here we investigate archived evidence of microbial processes and changing regional hydroclimate conditions by reconstructing deep Dead Sea chemical compositions from pore fluid major ion concentration and stable S, O, and C isotopes, together with lipid biomarkers preserved in the hypersaline deep Dead Sea ICDP-drilled core sediments dating to the early Holocene (ca. 10,000 years BP). Following a significant negative lake water balance resulting in salt layer deposits at the start of the Holocene, there was a general period of positive net water balance at 9500–8300 years BP. The pore fluid isotopic composition of sulfate exhibit evidence of intensified microbial sulfate reduction, where both (Formula presented.) and (Formula presented.) of sulfate show a sharp increase from estimated base values of 15.0‰ and 13.9‰ to 40.2‰ and 20.4‰, respectively, and a (Formula presented.) vs. (Formula presented.) slope of 0.26. The presence of the n-C17 alkane biomarker in the sediments suggests an increase of cyanobacteria or phytoplankton contribution to the bulk organic matter that reached the deepest parts of the Dead Sea. Although hydrologically disconnected, both the Mediterranean Sea and the Dead Sea microbial ecosystems responded to increased freshwater runoff during the early Holocene, with the former depositing the organic-rich sapropel 1 layer due to anoxic water column conditions. In the Dead Sea prolonged positive net water balance facilitated primary production and algal blooms in the upper waters and intensified microbial sulfate reduction in the hypolimnion and/or at the sediment–brine interface. © 2022 The Authors. Geobiology published by John Wiley & Sons Ltd. 2022 English 14724677 10.1111/gbi.12493 Geobiology 20 John Wiley and Sons Inc 518-532 Department of Earth and Environmental Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel; Geological Survey of Israel, Jerusalem, Israel; Department of Climate Geochemistry, Max Planck Institute for Chemistry, Mainz, Germany; Department of Earth Sciences, University of Geneva, Geneva, Switzerland; The Interuniversity Institute for Marine Sciences in Eilat, Eilat, Israel; Department of Earth Sciences, University of Cambridge, Cambridge, United Kingdom; Laboratoire de Géologie de Lyon, Univ. Lyon 1, CNRS, ENSL, Villeurbanne, France 4 biomarker; cyanobacterium; Holocene; isotopic composition; lipid; microbial activity; phytoplankton; reduction; sapropel; stable isotope; sulfate, Dead Sea; Mediterranean Sea, benzopyran derivative; sapropel; sulfate; water, chemistry; ecosystem; humic substance; lake; sediment, Benzopyrans; Ecosystem; Geologic Sediments; Humic Substances; Lakes; Sulfates; Water https://www.scopus.com/inward/record.uri?eid=2-s2.0-85127735070&doi=10.1111%2fgbi.12493&partnerID=40&md5=15613359a3d0b86f5bb4a41459a70ae8 cited By 0 E.J. Levy C. Thomas G. Antler I. Gavrieli A. Turchyn V. Grossi D. Ariztegui O. Sivan article Rull2022 Review 2022 10.1016/j.aca.2021.339003 Analytica Chimica Acta 1209 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85114369523&doi=10.1016%2fj.aca.2021.339003&partnerID=40&md5=f342fbcd4979d422030cdddf63ab6ede Cited by: 16; All Open Access, Hybrid Gold Open Access Fernando Rull Marco Veneranda Jose Antonio Manrique-Martinez Aurelio Sanz-Arranz Jesus Saiz Jesús Medina Andoni Moral Carlos Perez Laura Seoane Emmanuel Lalla Elena Charro Jose Manuel Lopez Luis Miguel Nieto Guillermo Lopez-Reyes article engelhardt2022icdp 2022 European Journal of Mineralogy 34 Copernicus GmbH 603--626 6 Artur Engelhardt Jürgen Koepke Chao Zhang Dieter Garbe-Schönberg Ana Patr{\'\i}cia Jesus article Lindberg2022559 The Mid-Pleistocene Transition (MPT) is a widely recognized global climate shift occurring between approximately 1250 and 700ka. At this time, Earth's climate underwent a major transition from dominant 40kyr glacial-interglacial cycles to quasi-100kyr cycles. The cause of the MPT remains a puzzling aspect of Pleistocene climate. Presently, there are few, if any, continuous MPT records from the Arctic, yet understanding the role and response of the high latitudes to the MPT is required to better evaluate the causes of this climatic shift. Here, we present new continental biomarker records of temperature and vegetation spanning 1142 to 752ka from Lake El'gygytgyn (Far East Russia). We reconstruct warm-season temperature variations across the MPT based on branched glycerol dialkyl glycerol tetraethers (brGDGTs). The new Arctic temperature record does not display an overall cooling trend during the MPT but does exhibit strong glacial-interglacial cyclicity. Spectral analysis demonstrates persistent obliquity and precession pacing over the study interval and reveals substantial sub-orbital temperature variations at 1/4900ka during the first "skipped"interglacial. Interestingly, Marine Isotope Stage (MIS) 31, which is widely recognized as a particularly warm interglacial, does not exhibit exceptional warmth in the Lake El'gygytgyn brGDGT record. Instead, we find that MIS 29, 27, and 21 were as warm or warmer than MIS 31. In particular, MIS 21 (1/4870 to 820ka) stands out as an especially warm and long interglacial in the continental Arctic while MIS 25 is a notably cold interglacial. Throughout the MPT, Lake El'gygytgyn pollen data exhibit a long-term drying trend, with a shift to an increasingly open landscape noted after around 900ka (Zhao et al., 2018), which is also reflected in our higher plant leaf wax (n-alkane) distributions. Although the mechanisms driving the MPT remain a matter of debate, our new climate records from the continental Arctic exhibit some similarities to changes noted around the North Pacific region. Overall, the new organic geochemical data from Lake El'gygytgyn contribute to expanding our knowledge of the high-latitude response to the MPT. © 2022 Kurt R. Lindberg et al. 2022 English 18149324 10.5194/cp-18-559-2022 Climate of the Past 18 Copernicus GmbH 559-577 University of Massachusetts Amherst, Amherst, MA 01003, United States; University at Buffalo, Buffalo, NY 14260, United States 3 biomarker; climate change; glacial-interglacial cycle; Pleistocene; vegetation cover; warming, Chukchi; Elgygytgyn Lake; Russian Federation https://www.scopus.com/inward/record.uri?eid=2-s2.0-85127722762&doi=10.5194%2fcp-18-559-2022&partnerID=40&md5=feca29161aac4e0d4d57ad4f90789a72 cited By 3 K.R. Lindberg W.C. Daniels I.S. Castañeda J. Brigham-Grette article Ying2022909 As a method for acquiring the velocity structure of underground strata and hidden structural faults, microtremor surveying is very popular for shallow exploration in cities and villages because of its advantages of no active source, convenient survey process, and strong anti-interference ability. To explore the deep geothermal resource potential of the northern Songliao Basin in greater detail, the subsurface fine velocity structure within the burial depth range from the Nenjiang Formation to the Denglouku Formation at the bottom of the depression was obtained by using the micro motion detection method in and around Songke Well No. 2 (SK-2) south of Anda City, Heilongjiang Province. Based on the spatial autocorrelation method (SPAC), the S-wave dispersion curve was extracted from the vertical component of the micro motion signal and transformed into the apparent S-wave velocity curve. Finally, through interpolation and smooth calculation, a two-dimensional underground S-wave velocity structure section spanning 9 km and reaching 4000 m beneath the surface was obtained. Analysis of the micro motion profile revealed that the subsurface S-wave velocity generally shows a trend of high velocity in the west and low velocity in the east. There are three obvious low-speed anomaly zones with depths ranging from 1400 m to 2800-100 m in the west, 2300 m in the east, and 3700 m to the east of well SK-2-indicating that there are likely faults or hidden fault structures at these locations. By combining these data with the stratigraphic data, the Quantou and Denglouku Formations were determined as the main units in this depth range, and the lithology is mostly interbedded sandstone and mudstone. These are suitable units for hydrothermal storage. The study shows that the lateral low-velocity anomaly of the surface wave results can be used as a basis of discrimination for identifying deep geothermal water storage structures and can provide direction for further clean energy investigation in this area. © 2022, Science Press. All right reserved. Article 2022 Chinese 10063021 10.3975/cagsb.2022.053001 Acta Geoscientica Sinica 43 Science Press 909 – 916 6 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85143508983&doi=10.3975%2fcagsb.2022.053001&partnerID=40&md5=c9c5e337b7b4b014e933304740e6d4d2 Cited by: 1 Heng-Cheng Ying Hong-Qiang Li Yu-Min Zhang Zhong-Yuan Jin Jia-Duo Zhang Wei Fu Lei Gao Dong-Zhao An Zong-Dong Pan Wei Wang He-Sheng Hou article Daniels2022900 Isoprenoid glycerol dialkyl glycerol tetraethers (iGDGTs) are commonly preserved molecular biomarkers of archaea whose distributions can be used to reconstruct past temperature, and possibly, methane and nitrogen cycling. To date, iGDGT systematics have not been widely investigated in Arctic lacustrine environments. Here, we analyze iGDGTs in sediments of Lake El'gygytgyn, located in the Russian Arctic, to reconstruct the paleoenvironmental conditions from the Pliocene to today using TEX86 and other indices. The TEX86-inferred temperature history shows a long-term warming trend, in stark contrast to other Arctic records and other proxies from Lake El'gygytgyn, suggesting that non-temperature factors obfuscate the use of TEX86 at this site. Other GDGT-based indices including the BIT Index, ΔRing Index, Methane Index and the GDGT-0/crenarchaeol ratio suggest that TEX86 is strongly influenced by archaeal community changes. The most significant community shifts are observed c. 2.4 Ma and record an increase in Euryarchaeota production and/or a decrease in Thaumarchaeota production, which was driven by the establishment of permafrost and perennial lake ice during the early Pleistocene. Overall, this study demonstrates an important interpretative framework for iGDGTs in lacustrine systems and describes variations in Arctic climate and lake biogeochemistry over timescales of thousands to millions of years. © 2021 John Wiley & Sons, Ltd. 2022 English 02678179 10.1002/jqs.3347 Journal of Quaternary Science 37 John Wiley and Sons Ltd 900-914 University of Massachusetts, Amherst, MA, United States 5 biogeochemistry; biomarker; climate variation; isoprenoid; lacustrine environment; lake water; lipid; microbial ecology; paleoclimate; paleoenvironment; permafrost; Pliocene; Pliocene-Pleistocene boundary; proxy climate record; timescale, Chukchi; Elgygytgyn Lake; Russian Federation https://www.scopus.com/inward/record.uri?eid=2-s2.0-85111034835&doi=10.1002%2fjqs.3347&partnerID=40&md5=3d3799a52ded88de9befcf289507f349 cited By 3 W.C. Daniels I.S. Castañeda J.M. Salacup M.H. Habicht K.R. Lindberg J. Brigham-Grette article Gupta2022619 Abstract: Under certain suitable geological conditions, anthropogenic seismicity due to gold/coal mining, geothermal and natural gas/oil production, filling of artificial water reservoirs, and high-pressure fluid injection has been reported globally. The reservoir-triggered seismicity (RTS) is most prominent, having been reported from hundreds of with at least five sites where earthquakes exceeding M 6 occurred, claiming human lives and destruction of properties. The most important correlate for RTS to occur is the height of water column in the reservoir. Certain common characteristics of the RTS sequences have been identified, which discriminate them from normal earthquake sequences. Factors influencing RTS include the highest water levels reached in the reservoir, duration of the retention of high-water levels and rate of loading/unloading. The mechanism of RTS is reviewed. The absence of knowledge of physical properties of rocks and fluids in the fault zone does not permit us to comprehend the RTS mechanism. Koyna, India, is found to be a very suitable site for such investigations as the earthquakes have been occurring in a small region of 20 × 30 km, at shallow depths (mostly within 8 km), with no other seismic source in the vicinity, and the region being accessible for all kinds of observation and investigations. The suitability of Koyna for setting up of a deep borehole laboratory was discussed during International Continental Drilling Program (ICDP) workshop in 2011 and accepted. Suggestions were made for some additional scientific works, which were completed during 2011–2014. The second ICDP workshop in 2014 approved of going ahead. A 3-km-deep Pilot Borehole has been completed in the vicinity of Donachiwada fault that hosted the main 10 December 1967 M 6.3 earthquake and several earthquakes of M ~ 5. The investigations being carried out are providing the necessary input to set up the proposed ~ 7-km-deep borehole laboratory. In this article, an overview of RTS globally and at Koyna, India, specifically is focused. Article Highlights: Global review of the reservoir-triggered seismicity (RTS) sitesFactors influencing RTS, their common characteristics and mechanismContinued seismicity at Koyna, India, and near-field studies © 2021, The Author(s), under exclusive licence to Springer Nature B.V. 2022 English 01693298 10.1007/s10712-021-09675-z Surveys in Geophysics 43 Springer Science and Business Media B.V. 619-659 CSIR, National Geophysical Research Institute, Hyderabad, 500007, India 2 Boreholes; Diffusion in liquids; Earthquakes; Faulting; Induced Seismicity; Petroleum reservoir engineering; Pore pressure; Stresses, Anthropogenics; Artificial water; Coal-mining; Deep boreholes; Drilling projects; Geological conditions; High water; Permeability; Reservoir-triggered seismicity; Water reservoir level, Abstracting, diffusion; earthquake magnitude; environmental stress; fault zone; permeability; pore pressure; seismicity, India; Koyna; Maharashtra https://www.scopus.com/inward/record.uri?eid=2-s2.0-85123101146&doi=10.1007%2fs10712-021-09675-z&partnerID=40&md5=e67f2e15a8351969a235fe9cf8598d47 cited By 3 H.K. Gupta article Ageli2022 Many large, ancient lakes support primarily planktonic-driven food webs. In contrast, the lowest trophic levels of the Malili Lakes of Sulawesi Island, Indonesia are dominated by benthic diatom communities composed mainly of endemic species. Centric diatoms are not observed in the current diatom assemblage and pennate pelagic species are rare. Using two deep drill-cores from Lake Towuti, we investigated whether the lake has always been dominated by benthic primary production. Despite the ultra-oligotrophic conditions observed in the lake today, we observed state changes characterized by productive planktonic communities and less productive, benthic-dominated diatom assemblages. Two periods of planktonic production, each lasting approximately 50 kyr, were dominated by a complex mixture of Aulacoseira spp., with valve densities >1.0 × 109 valves/g with a maximum biovolume of 3.5 × 1012 μm3/g. A similar planktonic assemblage was observed at much lower abundances (<107valves/g) in the deeper sediments (>1 Ma), during the earliest stages of lake formation. Two periods of increased benthic primary production of approximately ~11 kyr in duration, originating from the littoral zone of the lake, were also observed, one between the two planktonic phases and one above the last planktonic maxima. The benthic periods were dominated by Cymbopleura spp., with valve densities of approximately 2.0 × 108 valves/g and a maximum biovolume of 1.2 × 1011 μm3/g. Nonmetric multidimensional scaling analysis of sediment chemistry revealed that the benthic and pelagic states clustered with distinct chemical environments. The benthic phases were associated with well-mixed conditions in the lake whereas the planktonic phases were related to rapidly reoccurring water column mixing followed by intense stratification that generate nutrient recycling events. We conclude that lake mixing and nutrient cycling regimes regulated, in part, the switch between benthic and pelagic states in Lake Towuti. © 2022 Article 2022 English 00310182 10.1016/j.palaeo.2022.110937 Palaeogeography, Palaeoclimatology, Palaeoecology 594 Elsevier B.V. Greater Sunda Islands; Lake Towuti; Malili Lakes; South Sulawesi; Sulawesi; Sunda Isles; benthic-pelagic coupling; plankton; primary production; sediment chemistry; trophic level https://www.scopus.com/inward/record.uri?eid=2-s2.0-85127109089&doi=10.1016%2fj.palaeo.2022.110937&partnerID=40&md5=c3d1e956aa984d029a95e099469dca2f Cited by: 0 Mariam K. Ageli Paul B. Hamilton Andrew J. Bramburger R. Paul Weidman Zhuoyan Song James Russell Satria Bijaksana G. Douglas Haffner article Papale2022 Volcano science has been deeply developing during last decades, from a branch of descriptive natural sciences to a highly multi-disciplinary, technologically advanced, quantitative sector of the geosciences. While the progress has been continuous and substantial, the volcanological community still lacks big scientific endeavors comparable in size and objectives to many that characterize other scientific fields. Examples include large infrastructures such as the LHC in Geneva for sub-atomic particle physics or the Hubble telescope for astrophysics, as well as deeply coordinated, highly funded, decadal projects such as the Human Genome Project for life sciences. Here we argue that a similar big science approach will increasingly concern volcano science, and briefly describe three examples of developments in volcanology requiring such an approach, and that we believe will characterize the current decade (2020–2030): the Krafla Magma Testbed initiative; the development of a Global Volcano Simulator; and the emerging relevance of big data in volcano science. © 2022, The Author(s). 2022 English 02588900 10.1007/s00445-022-01524-0 Bulletin of Volcanology 84 Springer Science and Business Media Deutschland GmbH Istituto Nazionale Di Geofisica E Vulcanologia, Sezione Di Pisa, Via Cesare Battisti 53, Pisa, 56125, Italy 3 magma; volcano; volcanology https://www.scopus.com/inward/record.uri?eid=2-s2.0-85124949145&doi=10.1007%2fs00445-022-01524-0&partnerID=40&md5=a35501e0b53ee0b4f5ec90fa380f6374 cited By 1 P. Papale D. Garg article carter2022bimodal 2022 Journal of Geophysical Research: Solid Earth 127 Wiley Online Library e2021JB022669 1 Elliot J Carter Brian O’Driscoll Ray Burgess Patricia L Clay James Hepworth Oman Drilling Project Science Team article Ulfers2022 Robust age-depth models are essential for developing sophisticated interpretations of the sedimentological history in lake basins. In most cases, such models are created using an integrated geoscientific approach, including biostratigraphy, magnetostratigraphy and radiometric dating. In this study, we present an approach to construct age-depth models based on integrating downhole logging and seismic survey data when there are no samples available for dating. An example of this method is shown using data from Lake Ohrid (North Macedonia/Albania). First, we interpret seismic data and correlate downhole logging data from three sites - DEEP, Pestani and Cerava - to the LR04 benthic stack. We cross-check the resulting age-depth models using cyclostratigraphic methods, which deliver sedimentation rates that are on the same order of magnitude. The maximum age of the investigated sediments is based on lacustrine seismic marker horizons and is approximately 1 million years at DEEP/Pestani and 0.6 million years at Cerava. In the second step, we construct an artificial lithological log based on cluster analysis using the physical properties of the sediments and integrate it with the age-depth model. This allows an initial interpretation of the sedimentological history at Cerava and Pestani. Our methodological approach cannot substitute classical sediment core investigations, but we suggest that this two-step approach be applied to future projects of the International Continental Scientific Drilling Program. It can rapidly provide preliminary results on age and sediment type and is particularly useful when datable material is not available. © 2021 The Authors Article 2022 English 02773791 10.1016/j.quascirev.2021.107295 Quaternary Science Reviews 276 Elsevier Ltd Albania; Lake Ohrid; Macedonia; Cluster analysis; Lakes; Lithology; Seismic response; Seismic waves; Time series analysis; Albania; Borehole logging; Cyclostratigraphy; Depth models; Downhole methods; Downholes; Lake Ohrid; Macedonia; Sediment properties; Seismic interpretation; borehole logging; cluster analysis; magnetostratigraphy; modeling; sediment core; sedimentation; seismic data; seismic survey; Sediments https://www.scopus.com/inward/record.uri?eid=2-s2.0-85120755701&doi=10.1016%2fj.quascirev.2021.107295&partnerID=40&md5=a1ac3c11965f4684df2ae039e0827caa Cited by: 7; All Open Access, Hybrid Gold Open Access A. Ulfers C. Zeeden B. Wagner S. Krastel H. Buness T. Wonik article 2022 West-China Exploration Engineering 34 74-77+79 C Li B. Cheng S. Zhang H. Zhang article Nixon2022 We conducted a vertical seismic profile (VSP) in the borehole of International Ocean Discovery Program/International Continental Scientific Drilling Program Expedition 364 Site M0077 to better understand the nature of the seismic reflectivity and the in situ seismic properties associated with the Chicxulub impact structure peak ring. Extraction of the up-going wavefield from the VSP shows that a strong seismic reflection event imaged in seismic reflection data results from discontinuities in the elastic impedance Z (the product of density and wave speed) at the top and bottom of a zone of hydrothermally altered melt-bearing polymict breccia (suevite) that are characterized by anomalously low Z. Below this strong carbonate/suevite reflection event, the upgoing seismic wavefield is chaotic, indicating high levels of scattering from the suevites and underlying melt rocks and shocked granitoids of the peak ring, in contrast to the clear coherent reflections throughout the overlying Cenozoic sediments. We extract shear wave speeds, which, together with those provided from the complementary sonic log and densities from core scanning, allowed determination of VP/VS and Poisson's ratio v. These values are anomalously high relative to comparable terrestrial lithologies. We also calculate a variety of damage parameters for the disrupted peak ring granitoids. These values may assist in linking seismic observations to shock levels that are necessary to calibrate current impact models and may also be useful in assessing levels of fracturing within major fault zones. © 2022. The Authors. 2022 10.1029/2021GC009959 Geochemistry, Geophysics, Geosystems 23 Department of Physics, University of Alberta, Edmonton, AB, Canada; Department of Earth, Atmospheric and Planetary Science, Purdue University, West Lafayette, IN, United States; Géosciences Montpellier, Université de Montpellier, Montpellier, France; Institute for Geophysics, Jackson School of Geosciences, University of Texas at Austin, Austin, TX, United States; Department of Geological Sciences, Jackson School of Geosciences, University of Texas at Austin, Austin, TX, United States; Center for Planetary Systems Habitability, University of Texas at Austin, Austin, TX, United States; Lunar and Planetary Institute, Houston, TX, United States 3 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85127271273&doi=10.1029%2f2021GC009959&partnerID=40&md5=89bbbebeffbdfb758c298d435ddc4461 cited By 0 C.G. Nixon R. Kofman J. Lofi S.P.S. Gulick S. Saustrup G.L. Christeson D.A. Kring article https://doi.org/10.1029/2022GL098745 Abstract Cores recovered during the International Continental Scientific Drilling Program project “Drilling into Seismogenic zones of M2.0 to M5.5 earthquakes in deep South African Gold Mines” include fault breccia from within the aftershock cloud of the 2014 Orkney earthquake (M5.5). The breccia and surrounding intrusive rocks, probably lamprophyres rich in talc, biotite, calcite, and amphibole, had high magnetic susceptibilities owing to the presence of magnetite. All of these characteristics can be attributed to fluid-related alteration. Both the breccia and the lamprophyres had low friction coefficients and showed evidence of velocity strengthening, which is inconsistent with the occurrence of earthquakes. Variable amounts of talc, biotite, calcite, and amphibole within the lamprophyres might have produced complex frictional properties and spatial heterogeneity of fault stability. The altered lamprophyres may be the host rocks of the 2014 Orkney earthquake, but frictional complexity may have governed the magnitudes of the main- and aftershocks and their distributions. 2022 https://doi.org/10.1029/2022GL098745 Geophysical Research Letters 49 e2022GL098745 14 earthquake, fault drilling, lamprophyre https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2022GL098745 e2022GL098745 2022GL098745 T. Miyamoto T. Hirono Y. Yokoyama S. Kaneki Y. Yamamoto T. Ishikawa A. Tsuchiyama I. Katayama Y. Yabe R. J. Durrheim H. Ogasawara article Li2022 The Songliao Basin (SLB) in Northeast China has a succession of terrestrial sedimentary deposits that span much of the Cretaceous. The sedimentary records recovered from SLB allow us to investigate the relationship between astronomically forced climate and clastic sediment accumulation in a terrestrial setting from the mid to high latitudes. Here, we compiled high-resolution X-Ray Fluorescence (XRF) datasets (K/Ti, Rb/Sr, Ca/Ti), and gamma ray (GR) logging data from Member 2 of the Nenjiang Formation in the SK-1n borehole. Power spectral analysis of the GR data revealed that sedimentary cycles had wavelengths of 27.4 m, 6.56 m, 2.60 m, and 1.27 m. These wavelengths are interpreted as the orbital cycles of long-eccentricity, short-eccentricity, obliquity, and precession, respectively. We established an astronomical time scale by assuming that the 27.4 m cycles represent ~405 kyr eccentricity. We also applied correlation coefficient (COCO) analysis to identify the astronomical forcing periods. The chemical weathering history was classified by the relative changes of Rb/Sr and K/Ti ratios. The lower Rb/Sr and higher K/Ti values correspond to weak weathering, interpreted as arid periods, and vice versa. Ca/Ti ratios correlate with the humid periods and we attribute this correspondence to a salinity control on Ca/Ti. Furthermore, the unconventional 173-kyr obliquity cycle associated with the secular frequency interference of orbital inclinations between Earth and Saturn was recognized and manifested by humid/arid cliamtic oscillations, suggesting that high obliquity contributed to strengthening the hydrological cycles in SLB and bringing more precipitation and runoff towards the basin. The unique paleogeographic location and the existing paleoclimate simulations of SLB further demonstrated the existence of paleomonsoon variations in East Asia during the Late Cretaceous. © 2022 Article 2022 English 00310182 10.1016/j.palaeo.2022.111130 Palaeogeography, Palaeoclimatology, Palaeoecology 601 Elsevier B.V. China; Songliao Basin; chemical weathering; clastic sediment; correlation; Cretaceous; hydrological cycle; paleoclimate; spectral analysis https://www.scopus.com/inward/record.uri?eid=2-s2.0-85134357006&doi=10.1016%2fj.palaeo.2022.111130&partnerID=40&md5=f051d0a8250cf79e5ab2f0827eb35bd2 Cited by: 3 Xiang Li Yongjian Huang Zhifeng Zhang Chengshan Wang article Urrutia-Fucugauchi20222735 Modeling gravity and magnetic anomalies over the Chicxulub crater are used to constrain the structure, stratigraphy, and asymmetries. Chicxulub is a multiring ~ 200 km rim diameter structure with a central uplift and well-preserved peak ring. The low relief terrain and physical property contrasts have facilitated geophysical modeling of the structure and impactite deposits. Nevertheless, contrasting models have been obtained due to data resolution limitations, uneven coverage, non-uniqueness solutions, boundary conditions, and heterogeneous/anisotropic media. We employ a multi-technique approach based on regional–residual separation, spectral analysis, first and second derivatives, upward and downward analytical continuations, horizontal gradients, analytical signal, Euler deconvolution, reduction to the pole, and forward modeling to constraint the anomaly sources, geometry and depths. Forward modeling of gravity anomaly favors central uplift flat-top models, whereas magnetic models show irregular shapes with a peak towards the NE, at 4–5 km depth. Analysis shows the effects of intersecting regional anomalies in the semicircular pattern that limit the definition of asymmetries, which constrains impact angle and trajectory, crater structure and pre-existing target features. Models link lateral–vertical density and magnetic property contrasts, distinguishing non-magnetic pre-and post-impact carbonates and carbonate-rich breccias from melt and basement rich breccias, and displaced, fractured impactites and basement uplift. © 2022, The Author(s), under exclusive licence to Springer Nature Switzerland AG. 2022 10.1007/s00024-022-03074-0 Pure and Applied Geophysics 179 2735-2756 Programa Universitario de Perforaciones en Océanos y Continentes, Instituto de Geofísica, Universidad Nacional Autónoma de México, Ciudad Universitaria, Mexico City, 04510, Mexico; Instituto de Investigación Científica y Estudios Avanzados Chicxulub, Parque Científico y Tecnológico de Yucatán, Sierra Papacal, Yucatán, Merida, 97302, Mexico; Grupo KB de Mexico SA de CV, Av. Rio Mixocac 66-101, Colonia del Valle, Mexico City, 03100, Mexico; Coordinación de Plataformas Oceanográficas, Coordinación de la Investigación Científica, Universidad Nacional Autónoma de México, Ciudad Universitaria, Mexico City, 04510, Mexico 8 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85131535563&doi=10.1007%2fs00024-022-03074-0&partnerID=40&md5=7d22a5ca14f23c2a27150a03272833ed cited By 0 J. Urrutia-Fucugauchi O. Arellano-Catalán L. Pérez-Cruz I.A. Romero-Galindo article Jiskra2022346 Mercury (Hg) records in sediment archives inform past patterns of Hg deposition and the anthropogenic contribution to global Hg cycling. Natural climate variations complicate the interpretation of past Hg accumulation rates (HgARs), warranting additional research. Here, we investigated Hg stable isotopes in a ca. 8k year-long sediment core of Lake Titicaca and combined isotopic data with organic biomarkers and biogeochemical measurements. A wet period in the early Holocene (8000-7300 BP) induced strong watershed erosion, leading to a high HgAR (20.2 ± 6.9 μg m-2 year-1), which exceeded the 20th century HgAR (8.4 ± 1.0 μg m-2 year-1). Geogenic Hg input dominated during the early Holocene (fgeog = 79%) and played a minor role during the mid- to late Holocene (4500 BP to present; fgeog = 20%) when atmospheric Hg deposition dominated. Sediment Δ200Hg values and the absence of terrestrial lignin biomarkers suggest that direct lake uptake of atmospheric Hg(0), and subsequent algal scavenging of lake Hg, represented an important atmospheric deposition pathway (42%) during the mid- to late Holocene. During wet episodes of the late Holocene (2400 BP to present), atmospheric Hg(II) deposition was the dominant source of lake sediment Hg (up to 82%). Sediment Δ199Hg values suggest that photochemical reduction and re-emission of Hg(0) occurred from the lake surface. Hg stable isotopes show promise as proxies for understanding the history of Hg sources and transformations and help to disentangle anthropogenic and climate factors influencing HgAR observed in sediment archives. © 2022 The Authors. Published by American Chemical Society Article 2022 10.1021/acsearthspacechem.1c00304 ACS Earth and Space Chemistry 6 346 – 357 2 Lake Titicaca; atmospheric deposition; biogeochemistry; biomarker; climate change; erosion; geological record; Holocene; mercury (element); sediment core; stable isotope https://www.scopus.com/inward/record.uri?eid=2-s2.0-85124042506&doi=10.1021%2facsearthspacechem.1c00304&partnerID=40&md5=11a9695229e9de98c0b9e4d253c0444f Cited by: 4; All Open Access, Green Open Access Martin Jiskra Stéphane Guédron Julie Tolu Sherilyn C. Fritz Paul A. Baker Jeroen E. Sonke article Davison2022 Almost all meteorite impacts occur at oblique incidence angles, but the effect of impact angle on crater size is not well understood, especially for large craters. To improve oblique impact crater scaling, we present a suite of simulations of complex crater formation on Earth and the Moon over a range of impact angles, velocities and impactor sizes. We show that crater diameter is larger than predicted by existing scaling relationships for oblique impacts; there is little dependence on obliquity for impacts steeper than 45° from the horizontal. Crater depth, volume and diameter depend on impact angle in different ways—relatively shallower craters are formed by more oblique impacts. Our simulation results have implications for how crater populations are determined from impactor populations and vice-versa. They suggest that existing approaches to account for impact obliquity may underestimate the number of complex craters larger than a given size by as much as one-third. © 2022. The Authors. 2022 10.1029/2022GL101117 Geophysical Research Letters 49 Department of Earth Science and Engineering, Impacts & Astromaterials Research Centre, Imperial College London, London, United Kingdom 21 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85141934192&doi=10.1029%2f2022GL101117&partnerID=40&md5=362a3e22f57c5a248ed8538f88e698be cited By 0 T.M. Davison G.S. Collins article Chong20221151 Artificial neural network-trained models were used to predict gas hydrate saturation distributions in permafrost-associated deposits in the Eileen Gas Hydrate Trend on the Alaska North Slope (ANS), USA and at the Mallik research site in the Beaufort-Mackenzie Basin, Northwest Territories, Canada. The database of Logging-While-Drilling (LWD) and wireline logs collected at five wells (Mount Elbert, Iġnik Sikumi, and Kuparuk 7–11–12 wells at ANS, plus 2L-38 and 5L-38 wells at the Mallik research site) includes more than 10,000 depth points, which were used for training, validation, and testing the machine learning (ML) models. Data used in training the ML models include the well logs of density, porosity, electrical resistivity, gamma radiation, and acoustic wave velocity measurements. Combinations of two or three out of these five well logs were found to reliably predict the gas hydrate saturation with accuracy varying between 80 and 90% when compared to the gas hydrate saturations derived from Nuclear Magnetic Resonance (NMR)-based technique. The ML models trained on data from three ANS wells achieved high fidelity predictions of gas hydrate saturation at the Mallik site. The results obtained in this study indicate that ML models trained on data from one geological basin can successfully predict key reservoir parameters for permafrost-associated gas hydrate accumulations within another basin. A generalized approach for selecting a well log combination that can improve model accuracy is discussed. Overall, the study outcome supports earlier work demonstrating that ML models trained on non-NMR well logs are a viable alternative to physics-driven methods for predicting gas hydrate saturations. © 2022, The Author(s), under exclusive licence to Springer Nature Switzerland AG. 2022 English 14200597 10.1007/s10596-022-10151-9 Computational Geosciences 26 Springer Science and Business Media Deutschland GmbH 1151-1165 National Energy Technology Laboratory, 626 Cochrans Mill Road, P.O. Box 10940, Pittsburgh, PA 15236, United States; NETL Support Contractor, 626 Cochrans Mill Road, P.O. Box 10940, Pittsburgh, PA 15236, United States; National Energy Technology Laboratory, 3610 Collins Ferry Road, Morgantown, WV 26507, United States; NETL Support Contractor, 3610 Collins Ferry Road, Morgantown, WV 26507, United States; National Energy Technology Laboratory, 1450 Queen Avenue SW, Albany, OR 97321, United States; NETL Support Contractor, 1450 Queen Avenue SW, Albany, OR 97321, United States 5 artificial neural network; gas hydrate; hydrocarbon reservoir; hydrocarbon resource; machine learning; nuclear magnetic resonance, Canada; Mackenzie Delta; Northwest Territories https://www.scopus.com/inward/record.uri?eid=2-s2.0-85132604181&doi=10.1007%2fs10596-022-10151-9&partnerID=40&md5=d44b75dfe2403cdf266d576a0dbf9b6e cited By 1 L. Chong H. Singh C.G. Creason Y. Seol E.M. Myshakin article Platz2022 The region of West Bohemia and Upper Palatinate belongs to the West Bohemian Massif. The study area is situated at the junction of three different Variscan tectonic units and hosts the ENE-WSW trending Ohře Rift as well as many different fault systems. The entire region is characterized by ongoing magmatic processes in the intra-continental lithospheric mantle expressed by a series of phenomena, including e.g. the occurrence of repeated earthquake swarms and massive degassing of mantle derived CO2 in form of mineral springs and mofettes. Ongoing active tectonics is mainly manifested by Cenozoic volcanism represented by different Quaternary volcanic structures. All these phenomena make the Ohře Rift a unique target area for European intra-continental geo-scientific research. With magnetotelluric (MT) measurements we image the subsurface distribution of the electrical resistivity and map possible fluid pathways. Two-dimensional (2D) inversion results by Muñoz et al. (2018) reveal a conductive channel in the vicinity of the earthquake swarm region that extends from the lower crust to the surface forming a pathway for fluids into the region of the mofettes. A second conductive channel is present in the south of their model; however, their 2D inversions allow ambiguous interpretations of this feature. Therefore, we conducted a large 3D MT field experiment extending the study area towards the south. The 3D inversion result matches well with the known geology imaging different fluid/magma reservoirs at crust-mantle depth and mapping possible fluid pathways from the reservoirs to the surface feeding known mofettes and spas. A comparison of 3D and 2D inversion results suggests that the 2D inversion results are considerably characterized by 3D and off-profile structures. In this context, the new results advocate for the swarm earthquakes being located in the resistive host rock surrounding the conductive channels; a finding in line with observations e.g. at the San Andreas Fault, California. © 2022 The Authors Article 2022 English 00401951 10.1016/j.tecto.2022.229353 Tectonophysics 833 Elsevier B.V. Bohemian Massif; Electric conductivity; Magnetotellurics; Strike-slip faults; Structural geology; Volcanoes; 2-d inversions; Conductive channels; Earthquake swarms; Fluid pathways; Fluid/magma reservoir; Inversion results; Magma reservoirs; Ohře rift; Study areas; Volcanic structures; earthquake swarm; electrical resistivity; magnetotelluric method; Quaternary; rift zone; three-dimensional modeling; volcanism; volcanology; Earthquakes https://www.scopus.com/inward/record.uri?eid=2-s2.0-85129433829&doi=10.1016%2fj.tecto.2022.229353&partnerID=40&md5=4a99639dfcf40b15fc518d9144df8ff4 Cited by: 2; All Open Access, Green Open Access, Hybrid Gold Open Access Anna Platz Ute Weckmann Josef Pek Světlana Kováčiková Radek Klanica Johannes Mair Basel Aleid article lorenz_cosc-2_2022 {\textless}p{\textgreater}{\textless}strong class="journal-contentHeaderColor"{\textgreater}Abstract.{\textless}/strong{\textgreater} The Collisional Orogeny in the Scandinavian Caledonides (COSC) scientific drilling project aims to characterise the structure and orogenic processes involved in a major collisional mountain belt by multidisciplinary geoscientific research. Located in western central Sweden, the project has drilled two fully cored deep boreholes into the bedrock of the deeply eroded Early Paleozoic Caledonide Orogen. COSC-1 (2014) drilled a subduction-related allochthon and the associated thrust zone. COSC-2 (2020, this paper) extends this section deeper through the underlying nappes (Lower Allochthon), the main Caledonian décollement, and the upper kilometre of basement rocks. COSC-2 targets include the characterisation of orogen-scale detachments, the impact of orogenesis on the basement below the detachment, and the Early Paleozoic palaeoenvironment on the outer margin of palaeocontinent Baltica. This is complemented by research on heat flow, groundwater flow, and the characterisation of the microbial community in the present hard rock environment of the relict mountain belt. COSC-2 successfully, and within budget, recovered a continuous drill core to 2276 m depth. The retrieved geological section is partially different from the expected geological section with respect to the depth to the main décollement and the expected rock types. Although the intensity of synsedime{\textless}span id="page44"/{\textgreater}ntary deformation in the rocks in the upper part of the drill core might impede the analysis of the Early Paleozoic palaeoenvironment, the superb quality of the drill core and the borehole will facilitate research on the remaining targets and beyond. Protocols for sampling in the hard rock environment and subsequent sample preservation were established for geomicrobiological research and rock mechanical testing. For the former, a sparse sample series along the entire drill core was taken, while the target of the latter was the décollement. COSC-2 was surveyed by a comprehensive post-drilling downhole logging campaign and a combined borehole/land seismic survey in autumn 2021. This paper provides an overview of the COSC-2 (International Continental Scientific Drilling Project – ICDP 5054\_2\_A and 5054\_2\_B boreholes) operations and preliminary results. It will be complemented by a detailed operational report and data publication.{\textless}/p{\textgreater} 2022 feb English 1816-8957 10.5194/sd-30-43-2022 Scientific Drilling 30 43--57 https://sd.copernicus.org/articles/30/43/2022/ Publisher: Copernicus GmbH Henning Lorenz Jan-Erik Rosberg Christopher Juhlin Iwona Klonowska Rodolphe Lescoutre George Westmeijer Bjarne S. G. Almqvist Mark Anderson Stefan Bertilsson Mark Dopson Jens Kallmeyer Jochem Kück Oliver Lehnert Luca Menegon Christophe Pascal Simon Rejkjær Nick N. W. Roberts article Simpson2022 The peak-ring of the 66 Ma, ~180 km Chicxulub impact structure in the northern Yucatán peninsula and southern Gulf of Mexico was sampled during the International Ocean Discovery Program and International Continental Scientific Drilling Program (IODP–ICDP) Expedition 364 at Site M0077 (21.45° N, 89.95° W). Secondary clay minerals are pervasive throughout the upper peak-ring lithologies as a product of ubiquitous altered glass present throughout the impact melt and melt-bearing breccia sequence. Here we present the first detailed study of the clay mineralogy (microprobe, pXRD, spectral reflectance from 350 to 2500 nm) and isotope geochemistry (δ2H and δ18O) of the &lt;0.2 μm size-fraction from upper peak-ring lithologies. The clay mineralogy is dominated by smectitic clay minerals, whose composition varies with stratigraphic position. Trioctahedral Mg[sbnd]Fe smectite (var. saponite) is most common in Units or Subunits 2A, 2C, 3 and 4, while a section of Subunit 2B contains a more dioctahedral, Al-rich smectite. Higher porosity regions of the lower to mid, dioctahedral smectite-dominated intervals have higher δ18O (+14.2 to +18.6‰) whereas intervals dominated by trioctahedral smectite have lower δ18O (+10.4 to +14.1‰). The range of smectite δ2H (−105 to −87‰), in comparison to that of oxygen isotopes, is proportionally much less variable and unrelated to smectite mineralogy. When combined, the oxygen and hydrogen isotope compositions of the smectitic clay minerals suggest low temperature (~20 to 50 °C) formation from meteoric water-dominated fluids. The lower end of this temperature range is below current ambient conditions, which conceivably could suggest smectite formation before much of the overlying sedimentary rocks were deposited (~56 Ma?). Calculated temperatures are generally lower than those associated with impact-generated hydrothermal alteration. Calculated δ18O and δ2H of meteoric water-dominated fluids associated with low-temperature formation of these clay minerals are lower than known for modern meteoric water in the Yucatán region. The simplest explanation for the source of these ancient fluids is meteoric water-dominated Gulf Coast brines. A more remote possibility is orogenically-driven, long-distance transport of groundwater from highlands to the east via an artesian aquifer formed in part by fractured Mesozoic rocks extending laterally beneath the impact structure. © 2021 Elsevier B.V. 2022 10.1016/j.chemgeo.2021.120639 Chemical Geology 588 Department of Earth Sciences, The University of Western OntarioON N6A 3K7, Canada; Institute for Earth and Space Exploration, The University of Western OntarioON N6A 3K7, Canada; NASA Johnson Space Center, Universities Space Research Association, Houston, TX 77058, United States; Lunar and Planetary Institute, Universities Space Research Association, Houston, TX 77058, United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-85120414325&doi=10.1016%2fj.chemgeo.2021.120639&partnerID=40&md5=c3858c4e22d05a57283419069c66fa46 cited By 0 S.L. Simpson F.J. Longstaffe G.R. Osinski C.M. Caudill D.A. Kring article RN261 Journal Article 2022 1816-3459 10.5194/sd-31-31-2022 Scientific Drilling 31 31-49 Tomáš Fischer Pavla Hrubcová Torsten Dahm Heiko Woith Tomáš Vylita Matthias Ohrnberger Josef Vlček Josef Horálek Petr Dědeček Martin P. Lipus Jens Kallmeyer Frank Kruger Katrin Hannemann Michael Korn Horst Kämpf Thomas Reinsch Jakub Klicpera Daniel Vollmer Kyriaki Daskalopoulou article Rodbell2022301 Our understanding of the climatic teleconnections that drove ice-age cycles has been limited by a paucity of well-dated tropical records of glaciation that span several glacial–interglacial intervals. Glacial deposits offer discrete snapshots of glacier extent but cannot provide the continuous records required for detailed interhemispheric comparisons. By contrast, lakes located within glaciated catchments can provide continuous archives of upstream glacial activity, but few such records extend beyond the last glacial cycle. Here a piston core from Lake Junín in the uppermost Amazon basin provides the first, to our knowledge, continuous, independently dated archive of tropical glaciation spanning 700,000 years. We find that tropical glaciers tracked changes in global ice volume and followed a clear approximately 100,000-year periodicity. An enhancement in the extent of tropical Andean glaciers relative to global ice volume occurred between 200,000 and 400,000 years ago, during sustained intervals of regionally elevated hydrologic balance that modified the regular approximately 23,000-year pacing of monsoon-driven precipitation. Millennial-scale variations in the extent of tropical Andean glaciers during the last glacial cycle were driven by variations in regional monsoon strength that were linked to temperature perturbations in Greenland ice cores1; these interhemispheric connections may have existed during previous glacial cycles. © 2022, The Author(s). Article 2022 English 00280836 10.1038/s41586-022-04873-0 Nature 607 Nature Research 301 – 306 7918 Greenland; Ice Cover; Temperature; Amazon River; Arctic; Greenland; glaciation; monsoon; Pleistocene; teleconnection; article; glaciation; Greenland; information center; periodicity; precipitation; ice cover; temperature https://www.scopus.com/inward/record.uri?eid=2-s2.0-85133993341&doi=10.1038%2fs41586-022-04873-0&partnerID=40&md5=53751a36b337ca6f5e930ee15338265f Cited by: 2; All Open Access, Green Open Access, Hybrid Gold Open Access D.T. Rodbell R.G. Hatfield M.B. Abbott C.Y. Chen A. Woods J.S. Stoner D. McGee P.M. Tapia M. Bush B.L. Valero-Garcés S.B. Lehmann S.Z. Mark N.C. Weidhaas A.L. Hillman D.J. Larsen G. Delgado S.A. Katz K.E. Solada A.E. Morey M. Finkenbinder B. Valencia A. Rozas-Davila N. Wattrus S.M. Colman M.G. Bustamante J. Kück S. Pierdominici article Hinz20227103 A four-phase flow model is developed to capture the unconsolidated flow of gas, water, hydrate, and sand. The solid phase models are an extension of granular flow theory to unconsolidated hydrate-bearing sediment. A solid viscosity constitutive model is developed to model the frictional and cohesive contributions to the solid shear stress. In part 2 of this paper series, the model is validated against the Mallik 2007/2008 production tests. © 2022 American Chemical Society. All rights reserved. 2022 English 08885885 10.1021/acs.iecr.2c00211 Industrial and Engineering Chemistry Research 61 American Chemical Society 7103-7113 ThermoAnalytics Inc., 23440 Airpark Blvd., Calumet, MI 49913, United States; Department of Chemical and Biological Engineering, Wanger Institute for Sustainable Energy Research (WISER), Illinois Institute of Technology, Chicago, IL 60616, United States 20 Confined flow; Gas hydrates; Granular materials; Shear stress, Flow modelling; Four-phase; Gas sands; Gas-water; Granular flows; Methane production; Model development; Phase flow; Phase model; Solid phase models, Hydration https://www.scopus.com/inward/record.uri?eid=2-s2.0-85130744827&doi=10.1021%2facs.iecr.2c00211&partnerID=40&md5=dd0c1202605efbcec2ff7010e1b21c1c cited By 0 D. Hinz H. Arastoopour J. Abbasian article Hinz20227114 In this paper, the Mallik production tests are simulated using our four-phase flow model for an unconsolidated methane hydrate reservoir. Model development was outlined in part 1 of this paper series. The simulations suggest that the unconsolidated hydrate reservoir with sand production behaves like a naturally fracking reservoir. Solid deformation and the resultant permeability have a substantial effect on the gas production from an unconsolidated hydrate reservoir whether sand is produced or not. © 2022 American Chemical Society. All rights reserved. 2022 English 08885885 10.1021/acs.iecr.2c00212 Industrial and Engineering Chemistry Research 61 American Chemical Society 7114-7129 ThermoAnalytics Inc., 23440 Airpark Blvd., Calumet, MI 49913, United States; Department of Chemical and Biological Engineering, Wanger Institute for Sustainable Energy Research (WISER), Illinois Institute of Technology, Chicago, IL 60616, United States 20 Gas hydrates; Hydration; Petroleum reservoir engineering, Flow modelling; Four-phase; Methane hydrates; Methane production; Model development; Phase flow; Phase model; Production test; Sand production; Solid deformation, Methane https://www.scopus.com/inward/record.uri?eid=2-s2.0-85130715390&doi=10.1021%2facs.iecr.2c00212&partnerID=40&md5=c2812197ef364669eb916f1af2c474ba cited By 0 D. Hinz H. Arastoopour J. Abbasian article Rasmussen2022 The Upper Triassic Chinle Formation, cropping out in and around Petrified Forest National Park (PFNP) in northern Arizona, U.S.A., preserves an important non-marine biotic and sedimentologic record of Late Triassic key Earth-life events. In 2013, the Colorado Plateau Coring Project (CPCP) obtained a 520-m-long core of the Triassic strata at PFNP to study this sedimentary record in unequivocal superposition and, among other goals, to test hypotheses about the paleoenvironmental and biotic changes preserved in the Sonsela Member of the Chinle Formation, and specifically their link to the Manicouagan impact and the Adamanian-Revueltian biotic turnover event (A-R transition). We sampled the Sonsela Member of CPCP core 1A for bulk organic material and for pedogenic carbonates to establish the δ13Corg, δ13Ccarb, and δ18Ocarb records. Throughout much of the Sonsela Member, the stable isotope record is characterized by a relatively narrow range of values (δ13Corg = ~ −25 to −30‰; δ13Ccarb = ~ −7 to −10‰; and δ18Ocarb = ~ −5 to −8‰). Based on these data, we estimate mean annual precipitation and correlate our isotope record to two previously developed, high resolution, multi-proxy age models for the CPCP core. Our new data set supports three main conclusions based on these observations: (1) whereas the A-R transition and the Manicouagan impact event might correlate in time, establishing a causal relationship between those two events remains challenging; (2) the Manicouagan impact as well as the A-R transition are not linked to a clear geochemical perturbation preserved in the CPCP core; and (3) multiple proxies agree the climate became more arid throughout the Sonsela Member, possibly contributing to the Adamanian-Revueltian biotic turnover. © 2022 Elsevier B.V. 2022 English 00310182 10.1016/j.palaeo.2022.111060 Palaeogeography, Palaeoclimatology, Palaeoecology 601 Elsevier B.V. Department of Geology & Geophysics, University of Utah, Salt Lake City, UT 84112-0102, United States; Natural History Museum of Utah, University of Utah, Salt Lake City, UT 84108-1214, United States; Institute for Geophysics, Jackson School of Geosciences, University of Texas at Austin, Austin, TX 78758, United States; Berkeley Geochronology Center, Berkeley, CA 94709, United States; Earth and Environmental Sciences, Rensselaer Polytechnic Institute, Troy, NY 12180, United States; Department of Earth and Planetary Sciences, University of New Mexico, Albuquerque, NM 87131, United States; Department of Geosciences, University of Texas at Dallas, Richardson, TX 75080, United States; Department of Resource Management and Science, Petrified Forest National Park, Petrified Forest, AZ 86028, United States; School of Earth, Environment and Society, Bowling Green State University, Bowling Green, OH 43403, United States; Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY 10964, United States geochronology; historical record; paleoclimate; paleoenvironment; preservative; proxy climate record; stable isotope; Triassic, Arizona; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-85133408062&doi=10.1016%2fj.palaeo.2022.111060&partnerID=40&md5=dc24c32c1e195ffd71d9703666cc8556 cited By 0 C. Rasmussen R.B. Irmis R. Mundil M.F. Schaller J. Geissman W.G. Parker C.J. Lepre P.E. Olsen article Chávez-Lara2022 We present a palaeohydrological reconstruction of Lake Chalco from 70 to 11.5 ka BP based on ostracod records consisting of three species: Limnocytherina axalapasco, Candona patzcuaro, and Cypridopsis vidua. Overall, the presence of these species helped investigate Lake Chalco water level fluctuations, and thus water salinity variations. Moreover, this work helped improve our knowledge of L. axalapasco and Candona alchichica, two endemic species of Central Mexico, the latter of which was replaced by C. patzcuaro after the cold and dry MIS4. Five ostracod zones reflect the main environmental changes that occurred during the Late Pleistocene. During 70–62 ka BP (Zone 5), shallow and very variable salinity conditions were inferred with a possible occupancy of submerged macrophytes. The Lake Chalco water level increased from 62 to 49 ka BP (Zone 4) and relatively less saline conditions were inferred. The warmer period from of 49–39 ka BP (Zone 3) was characterised by lower lake levels and a gradually increasing salinity. The evaporation rates continued to increase during 39–27 ka BP (Zone 2). However, a higher runoff input helped maintain a relatively high lake level. Later on, cold and dry conditions from 27 to 11.5 ka BP (Zone 1) inhibited the ostracod occupancy in Lake Chalco. © 2022 Elsevier Ltd 2022 English 08959811 10.1016/j.jsames.2022.103944 Journal of South American Earth Sciences 119 Elsevier Ltd Instituto de Geofísica, Universidad Nacional Autónoma de Mexico, Ciudad Universitaria, CP, Ciudad de Mexico, 04510, Mexico; Instituto de Geología, Universidad Nacional Autónoma de Mexico, Ciudad Universitaria, CP, Ciudad de Mexico, 04510, Mexico; Posgrado en Ciencias de la Tierra, Universidad Nacional Autónoma de Mexico, Ciudad Universitaria, CP, Ciudad de Mexico, 04510, Mexico environmental change; evapotranspiration; ostracod; paleohydrology; Pleistocene; salinity; warming; water level, Lake Chalco; Mexico [North America] https://www.scopus.com/inward/record.uri?eid=2-s2.0-85137371288&doi=10.1016%2fj.jsames.2022.103944&partnerID=40&md5=13adccdbed3b5867d03da3f6de5c5abc cited By 2 C.M. Chávez-Lara S. Lozano-García B. Ortega-Guerrero D. Avendaño M. Caballero-Miranda article Garbe-Schönberg2022 Due to its inaccessibility, no complete and coherent data set exists for the composition of modern fast-spreading oceanic crust. We sampled outcrops through 6,500 m of fossil oceanic crust in the Oman Ophiolite (Wadi Gideah Transect) that is regarded as best analogue of fast-spreading crust on land. Here we report a complete set of whole-rock major and trace element data displaying systematic and contrasting compositional trends in lower and upper gabbros being correlated with stratigraphic depth. A significant discontinuity in crystallization regime is observed at ∼3,525 m above the mantle-crust boundary: gabbros below ∼3,525 m have in general very low incompatible element mass fractions which develop upwards in a barely noticeable way to more differentiated compositions while Mg# decreases. More pronounced trends indicating progressive fractionation of ascending melts can be observed for incompatible elements and their element ratios as a consequence of in situ crystallization. Locally, more variable compositions within narrow depth intervals testify for advanced differentiation in situ within individual sills. Gabbros above ∼3,525 m become significantly more evolved and show considerable variations in composition. Fractional crystallization and mixing processes in a transient axial melt lens control the composition of isotropic “varitextured” gabbros and sheeted dike basalts where fractionation of high field strength elemental ratios is minor. New average compositions of fast-spread (paleo) oceanic crust are reported for major and 38 trace elements. Comparison with new data from Wadi Khafifah close to Wadi Gideah suggests robustness of crustal accretion processes in both space and time. © 2022. The Authors. 2022 English 21699313 10.1029/2021JB022734 Journal of Geophysical Research: Solid Earth 127 John Wiley and Sons Inc Institute of Geosciences, Kiel University, Kiel, Germany; Department of Physics and Earth Sciences, Jacobs University Bremen, Bremen, Germany; Institute of Mineralogy, Leibniz University Hannover, Hannover, Germany 6 gabbro; geochemistry; oceanic crust; seafloor spreading; trace element; transect, Oman; Semail Ophiolite https://www.scopus.com/inward/record.uri?eid=2-s2.0-85132874756&doi=10.1029%2f2021JB022734&partnerID=40&md5=dfc8fa5cd05fdcbe4cbfd5fa04a8342e cited By 1 D. Garbe-Schönberg J. Koepke S. Müller D. Mock T. Müller article Han2022449 There are multiple gas logging anomalies in the Shahezi Formation, Songliao Basin, indicating its tight gas potential. However, deep tight reservoirs in the area have strong heterogeneity, thin thickness, interlayer development and various types. Based on the analysis of conventional well log of well SK-2, we used elemental capture spectroscopy (ECS) well logging to finely retrieve the mineral component content for accurate lithology identification, and subsequently identified five types of reservoirs by crossplot analysis. Combined with petrophysical experimental data, we further obtained the reservoir evaluation parameters such as variable skeleton porosity, brittleness index, and organic carbon content, which allowed us to categorize the reservoirs into three groups based on the well logging data and comprehensive evaluation indexes. In the Shahezi Formation (3730-4500 m), the porosity values range between 5%-9%, and the brittleness indexes range between 45%-60%. TOC of adjacent source rock is generally high, with relatively large accumulative thickness, and depth intervals at 3798-3831, 3950-3990 and 4150-4200 m show favorable tight gas potential for exploration and development. We demonstrated in this paper that, ECS well logging can accurately evaluate tight gas reservoirs so as to provide a reference basis for fracturing optimization in tight reservoirs. © 2022, Editorial Office of Earth Science Frontiers. All right reserved. Article 2022 Chinese 10052321 10.13745/j.esf.sf.2021.1.60 Earth Science Frontiers 29 Science Frontiers editorial department 449 – 458 1 Brittleness; Fracture mechanics; Gases; Lithology; Organic carbon; Petroleum reservoir evaluation; Petroleum reservoirs; Plasticity; Porosity; Well logging; Brittleness index; Case-studies; Conventional well logs; Elemental capture spectroscopy; Gas logging; Gas potential; Shahezi formations; Songliao basin; Strong heterogeneities; Tight reservoir; Tight gas https://www.scopus.com/inward/record.uri?eid=2-s2.0-85124895933&doi=10.13745%2fj.esf.sf.2021.1.60&partnerID=40&md5=28cce9c69d9381040e96b0795d7ebd5e Cited by: 2 Shuangbiao Han Zhiyuan Tang Songtao Bai Lei Wan Yurun Rui Yuan Gao Yongjian Huang Chengshan Wang article Gosling2022 Article 2022 10.1126/science.abg4618 Science 376 6593 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85129370139&doi=10.1126%2fscience.abg4618&partnerID=40&md5=849b73ea845ae6d71283eedf2c51e1e2 Cited by: 22; All Open Access, Bronze Open Access William D. Gosling Charlotte S. Miller Timothy M. Shanahan Philip B. Holden Jonathan T. Overpeck Frank Langevelde article Zhang2022654 The SK-2 of China Continental Scientific Drilling Project (CCSD) in the Songliao Basin recorded the Cretaceous continental sedimentary data. The continuous, multi-parameter, high-resolution geophysical logging data provided an opportunity to study the variation in sedimentation rate in the Songliao Basin. In this study, we used GR, Th, K, and Th/K logging data to calculate the sedimentation rate using the astronomical cycle method and discussed the main controlling factors affecting sediment formation. Spectral analysis results of various logging data showed that the Denglouku Formation has recorded the information of the great Milankovitch cycle information, and the sedimentation process is affected by the driving force of the astronomical orbit. Th data are highly sensitive to astronomical period information, and comprehensively considering the results of various logging data, a continuous and relatively accurate sedimentation rate has been obtained. The sedimentation rate showed a trend from high to low with depth from bottom to top. Sedimentation of the second to third members of the Denglouku Formation was mainly controlled by the faulting activities of the basin, and the overall sedimentation rate was high, reaching a maximum of 16.2 cm/ka. From then on to the fourth member of the Denglouku Formation, the basin transformed into a regional depression structure owing to the gradual weakening of the rifting activity, and the formation had a low sedimentation rate; the lowest rate was 5.9 cm/ka. This study established a continuous sedimentation rate profile of the Denglouku Formation from CCSD SK-2, which provided logging evidence for revealing the geological law of the transition from rifting activity to depression activity in the Songliao Basin. © 2022, Science Press. All right reserved. 2022 Chinese 10063021 10.3975/cagsb.2022.061602 Acta Geoscientica Sinica 43 Science Press 654-664 Key Laboratory of Geo-detection, Ministry of Education, China University of Geosciences (Beijing), Beijing, 100083, China; School of Geophysics and Information Technology, China University of Geosciences (Beijing), Beijing, 100083, China; Well-Tech Department of China Oilfield Services Limited, Langfang, 065201, China 5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85138637251&doi=10.3975%2fcagsb.2022.061602&partnerID=40&md5=d8b9a7c66522f4a9e059f56df213dad0 cited By 0 H.-D. Zhang C.-C. Zou C. Peng Y.-Q. Yang article Ogasawara2022259 Article 2022 10.2472/jsms.71.259 Zairyo/Journal of the Society of Materials Science, Japan 71 259 – 264 3 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85128490409&doi=10.2472%2fjsms.71.259&partnerID=40&md5=672ad2365b3e3320766b2ff4531bcf94 Cited by: 0; All Open Access, Gold Open Access Hiroshi Ogasawara Yoshihiro Mima Akimasa Ishida Siyanda Mngadi Mitsuya Higashi Yasuo Yabe Akio Funato Takatoshi Ito Masao Nakatani Raymond Durrheim article Prause2022 Low-temperature hydrothermal alteration of basaltic glass on the seafloor has important implications on the chemical evolution of the oceanic crust and seawater composition. However, mass fluxes resulting from seawater-glass interaction in this type of environment remain poorly understood. This study presents new results on element mobilities for the palagonitization of basaltic glass and bulk rock hydrothermal alteration at Surtsey volcano, Iceland over a time period of ~50-years. Assessments of element mobilities were based on 1) immobile trace element isocon mass balance for palagonitization, 2) the assumption of large scale TiO2 immobility during bulk rock alteration and 3) chemical analyses of pore fluids and authigenic minerals. Element mobilities of glass alteration vary between initial palagonitization and subsequent palagonite maturation: Initially, palagonitization of sideromelane leaches SiO2, Al2O3, MgO, CaO, Na2O, K2O from the glass. Following this, the maturation of the palagonitized glass causes re-uptake of all of the abovementioned elements except for CaO, which shows either no change or slight uptake, and Na2O, which continues to be lost from the palagonitized glass. Among major elements TiO2 and FeO can be considered immobile during palagonitization, but not during the subsequent aging process of palagonitized glass. Among trace elements Hf, Ta, Zr, Nb, Y and REE were found to be immobile at all stages of the alteration. On the bulk rock scale, comprising both glass alteration and the formation of authigenic phases, early-stage alteration at Surtsey releases SiO2, Al, Mg and Ca to the fluid, whereas late-stage alteration poses a sink of SiO2, Al, Mg, Ca and Na. Net element budgets during early- and late-stage alteration indicate that chemical exchange between basaltic tuffs and seawater derived fluids at Surtsey acts as a long-term source of dissolved Ca, Al and SiO2 for seawater as well as a long-term sink for seawater Mg and Na. © 2022 Elsevier B.V. 2022 English 03770273 10.1016/j.jvolgeores.2022.107581 Journal of Volcanology and Geothermal Research 429 Elsevier B.V. Institute of Earth Sciences, University of Iceland, Reykjavík, Iceland; Research Centre Breiðdalsvík, University of Iceland, Breiðdalsvík, Iceland; University of Bremen, Department of Geosciences, Bremen, Germany; Università degli Studi di Napoli Federico II, Dipartimento di Scienze della Terra, dell'Ambiente e delle Risorse (DiSTAR), Naples, Italy Alumina; Aluminum oxide; Basalt; Budget control; Calcium; Chemical analysis; Clay alteration; Glass; Iron oxides; Magnesia; Nanocomposites; Seawater; Silica; Silicon; Sodium compounds; Temperature; Titanium dioxide; Trace elements, Basaltic glass; Bulk rocks; Element mobility; Hydrothermal alterations; ICDP; Icelands; Mass balance; Palagonitization; Surtsey volcano; SUSTAIN, Volcanoes, basalt; glass; hydrothermal alteration; hydrothermal system; mass balance; oceanic crust; seawater; trace element, Iceland; Surtsey https://www.scopus.com/inward/record.uri?eid=2-s2.0-85133443087&doi=10.1016%2fj.jvolgeores.2022.107581&partnerID=40&md5=44d9be155b03fc808d2ee90e49a96541 cited By 0 S. Prause T.B. Weisenberger B.I. Kleine P. Monien C. Rispoli A. Stefánsson article SardarAbadi2022 Understanding the moisture history of low latitudes from the most recent glacial period of the latest Pleistocene to post-glacial warmth in continental tropical regions is hampered by the lack of continuous time series. We conducted downhole spectral gamma (γ) ray and magnetic susceptibility logs over 300 m of lacustrine deposits of Lake Chalco (Mexico City) to reconstruct an age-depth model using an astronomical and correlative approach, and to reconstruct long-term moisture availability. Our results suggest that the Lake Chalco sediments contain several rhythmic alternations with a quasi-cyclic pattern comparable to the Pleistocene benthic stack. This allows us to calculate a time span of about 500,000 years for this sediment deposition. We developed proxies for moisture, detrital input, and salinity, all based on the physical properties of γ-ray spectroscopy and magnetic susceptibility. Our results indicate that Lake Chalco formed during Marine Isotope Stage 13 (MIS13) and the lake level gradually increased over time until the interglacial MIS9. Moisture content is generally higher during interglacials than during glacials. However, two periods, namely MIS6 and MIS4, have higher moisture contents. We developed a model by comparing the obtained moisture proxy with climatic drivers, to understand how different climate systems drove effective moisture availability in the Chalco sub-basin over the past 500,000 years. Carbon dioxide, eccentricity, and precession are all key drivers of the moisture content of Lake Chalco over the past 500,000 years. © 2022 The Authors 2022 English 02773791 10.1016/j.quascirev.2022.107739 Quaternary Science Reviews 294 Elsevier Ltd LIAG, Leibniz Institute for Applied Geophysics, Stilleweg 2, Hannover, 30655, Germany Carbon dioxide; Climate models; Continuous time systems; Gamma rays; Glacial geology; Lakes; Magnetic susceptibility; Magnetism; Moisture determination; Sediments; Tropics, %moisture; Authigenic; Authigenic urania; Cyclostratigraphy; Depth models; Milankovitch cycle; Palaeoclimatology; Quaternary; Spectral gamma rays; Tropical north america, Moisture, astronomy; borehole logging; interglacial; lacustrine deposit; lake level; magnetic susceptibility; moisture content; paleoclimate; Pleistocene; Postglacial; precession; reconstruction; uranium, Federal District [Mexico]; Lake Chalco; Mexico City; Mexico [North America] https://www.scopus.com/inward/record.uri?eid=2-s2.0-85138817916&doi=10.1016%2fj.quascirev.2022.107739&partnerID=40&md5=42779e5a48290b7909df06c828116dc1 cited By 0 M. Sardar Abadi C. Zeeden A. Ulfers T. Wonik article Chávez-Lara2022359 A sediment record from Lake Chalco, Basin of Mexico, revealed the presence of two endemic ostracod species during the latter part of Marine Isotope Stages (MIS) 6 (146–130 ka) and MIS5 (130–72 ka), namely Candona alchichica and Limnocytherina axalapasco. Higher abundance of C. alchichica was found during MIS6, when prevailing conditions were cold, lake waters were fresh, and relatively deep bottom waters were anoxic. The species is typically associated with saline environments today, consistent with its presence in MIS5 sediments. The Chalco record, however, reveals that it coexisted with freshwater diatom species during MIS6. Thus, we suggest that C. alchichica had a wider salinity tolerance, ranging from freshwater to more saline environments. Examination of MIS5 substages provides further insights into ostracod species responses to changing lake conditions. During MIS5e, the lake water level declined and salinity and dissolved oxygen in the water column increased, thereby favouring L. axalapasco productivity, whereas C. alchichica productivity decreased. Enhanced runoff and lower than average evaporation during MIS5d coincided with the increasing abundance of C. alchichica, suggesting a period of relatively high lake level and more dilute waters. These environmental conditions, however, changed during MIS5c when lake stage dropped once again and L. axalapasco abundance increased. Shallow conditions during this substage were optimal for L. axalapasco. Subsequently, as the lake level continued to decline during MIS5b, both ostracod species disappeared from the sediment record. Finally, during MIS5a, runoff increased and both ostracod species reappeared in the record, with L. axalapasco dominating, suggesting another period of lake level recovery. Increased evaporation rates during the last part of this substage (75–72 cal ka BP) may have led to disappearance of ostracods from the sediment record. Overall, during MIS5, we detected higher L. axalapasco, which represent relatively shallow lake conditions. © 2022, The Author(s), under exclusive licence to Springer Nature B.V. 2022 English 09212728 10.1007/s10933-022-00237-w Journal of Paleolimnology 67 Springer Science and Business Media B.V. 359-373 Instituto de Geología, Universidad Nacional Autónoma de Mexico, Ciudad Universitaria, Mexico, 04510, Mexico; Instituto de Geofísica, Universidad Nacional Autónoma de Mexico, Ciudad Universitaria, Mexico, 04510, Mexico; Posgrado en Ciencias de la Tierra, Universidad Nacional Autónoma de Mexico, Ciudad Universitaria, Mexico, 04510, Mexico; Large Lakes Observatory &, Department of Earth and Environmental Sciences, University of Minnesota Duluth, Duluth, MN 55812, United States 4 dissolved oxygen; environmental conditions; lake level; lake water; marine isotope stage; ostracod; paleoecology; runoff; seawater, Lake Chalco; Mexico [North America]; Valley of Mexico https://www.scopus.com/inward/record.uri?eid=2-s2.0-85125750119&doi=10.1007%2fs10933-022-00237-w&partnerID=40&md5=55775fb1716c2acef5c2f08b878604a4 cited By 4 C.M. Chávez-Lara S. Lozano-García B. Ortega-Guerrero M. Caballero-Miranda D. Avendaño E.T. Brown article Kästner202266 Strong anisotropy of seismic velocity in the Earth's crust poses serious challenges for seismic imaging. Where in situ seismic properties are not available, the anisotropy can be determined from velocity analysis of surface and borehole seismic profiles. This is well established for dense, long-offset reflection seismic data. However, it is unknown how applicable this approach is for sparse seismic reflection data with low fold and short offsets in anisotropic metamorphic rocks. Here, we show that anisotropy parameters can be determined from a sparse 3-D data set at the COSC-1 borehole site in the Swedish Caledonides and that the results agree well with the seismic anisotropy parameters determined from seismic laboratory measurements on core samples. Applying these anisotropy parameters during 3-D seismic imaging improves the seismic image of the high-amplitude reflections especially in the vicinity of the lower part of the borehole. Strong reflections in the resulting seismic data show good correlation with the borehole-derived lithology. Our results aid the interpretation and extrapolation of the seismic stratigraphy of the Lower Seve Nappe in Jämtland and other parts in the Caledonides. Article 2022 jan 0956-540X 10.1093/gji/ggab339 Geophysical Journal International 228 66 – 77 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85116561589&doi=10.1093%2fgji%2fggab339&partnerID=40&md5=953ebafe73044d2db97c4b99005abc76 Cited by: 2; All Open Access, Hybrid Gold Open Access Felix Kästner Dirk Klaeschen Christian Berndt Simona Pierdominici Peter Hedin article Simakin2022 Article 2022 10.1093/petrology/egac074 Journal of Petrology 63 8 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85160756713&doi=10.1093%2fpetrology%2fegac074&partnerID=40&md5=a3966fa4fab8fa77d0e3b4b7598f0ed1 Cited by: 5 A.G. Simakin I.N. Bindeman article Warr2022 Deep within the Precambrian basement rocks of the Earth, groundwaters can sustain subsurface microbial communities, and are targets of investigation both for geologic storage of carbon and/or nuclear waste, and for new reservoirs of rapidly depleting resources of helium. Noble gas-derived residence times have revealed deep hydrological settings where groundwaters are preserved on millions to billion-year timescales. Here we report groundwaters enriched in the highest concentrations of radiogenic products yet discovered in fluids, with an associated 86Kr excess in the free fluid, and residence times &gt;1 billion years. This brine, from a South African gold mine 3 km below surface, demonstrates that ancient groundwaters preserved in the deep continental crust on billion-year geologic timescales may be more widespread than previously understood. The findings have implications beyond Earth, where on rocky planets such as Mars, subsurface water may persist on long timescales despite surface conditions that no longer provide a habitable zone. © 2022, The Author(s). 2022 English 20411723 10.1038/s41467-022-31412-2 Nature Communications 13 Nature Research Department of Earth Sciences, University of Toronto, Toronto, ON M5S 3B1, Canada; Department of Earth Sciences, University of Oxford, Oxford, OX1 3AN, United Kingdom; Department of Geosciences, Princeton University, Princeton, NJ 08544, United States; Biology Department, New Mexico Institute of Mining and Technology, Socorro, NM 87801, United States; IPGP, Sorbonne Paris Cité, 1 rue Jussieu, Paris, 75005, France 1 ground water; helium; helium 4; inert gas; krypton 86; neon; radioisotope; unclassified drug; uranium; xenon; xenon 136; inert gas, basement rock; concentration (composition); groundwater resource; helium; microbial community; Precambrian, air pollution; Article; astronomy; chemical composition; concentration (parameter); controlled study; geological time; gold mining; hydrosphere; Precambrian; sediment; South Africa; surface property; water residence time; water supply; geology; microflora, South Africa, Earth, Planet; Geology; Groundwater; Microbiota; Noble Gases https://www.scopus.com/inward/record.uri?eid=2-s2.0-85133137290&doi=10.1038%2fs41467-022-31412-2&partnerID=40&md5=6b3c0e403955ab1b367bf965edb44c4e cited By 2 O. Warr C.J. Ballentine T.C. Onstott D.M. Nisson T.L. Kieft D.J. Hillegonds B. Sherwood Lollar article bergsten2022culturable 2022 10.3390/ microorganisms10061177 Microorganisms 10 MDPI 1177 6 Pauline Bergsten Pauline Vannier Julie Frion Alan Mougeolle Viggó Thór Marteinsson article Ulfers2022 Article 2022 10.1016/j.quascirev.2022.107413 Quaternary Science Reviews 280 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85124627552&doi=10.1016%2fj.quascirev.2022.107413&partnerID=40&md5=4abf0f72771ab12c6dd9d926ea144d89 Cited by: 19; All Open Access, Hybrid Gold Open Access Arne Ulfers Christian Zeeden Silke Voigt Mehrdad Sardar Abadi Thomas Wonik article Kaskes2022895 This study presents a new classification of a ~100-m-thick crater suevite sequence in the recent International Ocean Discovery Program (IODP)-International Continental Scientific Drilling Program (ICDP) Expedition 364 Hole M0077A drill core to better understand the formation of suevite on top of the Chicxulub peak ring. We provide an extensive data set for this succession that consists of whole-rock major and trace element compositional data (n = 212) and petrographic data supported by digital image analysis. The suevite sequence is subdivided into three units that are distinct in their petrography, geochemistry, and sedimentology, from base to top: the ~5.6-m-thick non-graded suevite unit, the ~89-m-thick graded suevite unit, and the ~3.5-m-thick bedded suevite unit. All of these suevite units have isolated Cretaceous planktic foraminifera within their clastic groundmass, which suggests that marine processes were responsible for the deposition of the entire M0077A suevite sequence. The most likely scenario describes that the first ocean water that reached the northern peak ring region entered through a N-NE gap in the Chicxulub outer rim. We estimate that this ocean water arrived at Site M0077 within 30 minutes after the impact and was relatively poor in rock debris. This water caused intense quench fragmentation when it interacted with the underlying hot impact melt rock, and this resulted in the emplacement of the ~5.6-m-thick hyaloclastite-like, non-graded suevite unit. In the following hours, the impact structure was flooded by an ocean resurge rich in rock debris, which caused the phreatomagmatic processes to stop and the ~89-m-thick graded suevite unit to be deposited. We interpret that after the energy of the resurge slowly dissipated, oscillating seiche waves took over the sedimentary regime and formed the ~3.5-m-thick bedded suevite unit. The final stages of the formation of the impactite sequence (estimated to be <20 years after impact) were dominated by resuspension and slow atmospheric settling, including the final deposition of Chicxulub impactor debris. Cumulatively, the Site M0077 suevite sequence from the Chicxulub impact site preserved a high-resolution record that provides an unprecedented window for unravelling the dynamics and timing of proximal marine cratering processes in the direct aftermath of a large impact event. © 2021 The Authors. Gold Open Access 2022 10.1130/B36020.1 Bulletin of the Geological Society of America 134 895-927 Research Unit: Analytical, Environmental & Geo-Chemistry, Department of Chemistry, Vrije Universiteit Brussel, AMGC-WE-VUB, Pleinlaan 2, Brussels, 1050, Belgium; Laboratoire G-Time, Université Libre de Bruxelles, ULB, Av. F.D. Roosevelt 50, Brussels, 1050, Belgium; Department of Lithospheric Research, University of Vienna, Althanstrasse 14, Vienna, A-1090, Austria; Natural History Museum, Burgring 7, Vienna, A-1010, Austria; Department of Earth Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1085, Amsterdam, 1081 HV, Netherlands; Eyring Materials Center, Arizona State University, Tempe, AZ 85287, United States; Institute for Geophysics & Department of Geological Sciences, Jackson School of Geosciences, University of Texas at Austin, Austin, TX 78758, United States; Center for Planetary Systems Habitability, University of Texas at Austin, Austin, TX 78712, United States 3-4 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85113288682&doi=10.1130%2fB36020.1&partnerID=40&md5=77a53069f3320d8fecfb282dbd3ce529 cited By 11 P. Kaskes S.J. Graaff J.-G. Feignon T. Déhais S. Goderis L. Ferrière C. Koeberl J. Smit A. Wittmann S.P.S. Gulick V. Debaille N. Mattielli P. Claeys article Scuderi2022290 Observations of slow earthquakes and tremor have raised fundamental questions about the physics of quasi-dynamic rupture and the underlying fault zone processes. The presence of serpentinite at P-T conditions characteristic of deep tremor and slow earthquakes suggests that it plays an important role in controlling complex fault slip behaviour. Here, we report on experiments designed to investigate the frictional behaviour of serpentinite sampled from outcrop exposures (SO1 and SO2) of altered ultramafic rocks present at depth, and recovered from the SAFOD borehole (G27). XRD analyses reveal the presence of chrisotyle, lizardite, kaolinite, talc in SO1; lizardite, clinochlore and magnetite in SO2; and lizardite, quartz and calcite in G27. We sheared fault gouge in a double-direct shear configuration using a true triaxial deformation apparatus. The effective normal stress was varied from 2 to 40 MPa. We conducted velocity stepping tests and slide-hold-slide (SHS) tests in each experiment to characterize frictional stability and healing. At the end of each experiment, post-shear permeability was measured and the samples were recovered for microstructural analysis. The steady-state friction coefficient was μ = 0.17 for SO1, μ = 0.33 for SO2 and μ = 0.53 for G27. Overall, the gouges exhibit velocity strengthening behaviour, and become nearly velocity neutral at 40 MPa effective normal stress. SHS tests show positive healing rates for SO2 and G27, whereas SO1 exhibits zero or negative healing rates. Permeability decreases with increasing σn', with SO1 (k = 10-20 m2) showing the lowest values. Microstructural observations reveal a well-developed R-Y-P fabric in SO1, which is not observed in SO2 and G27. We posit that the development of shear fabric controlled by mineralogy governs frictional and hydrological properties. In this context, when serpentinite is associated with other weak phyllosilicate minerals, frictional stability and hydrological properties can vary greatly, with a potential control on the mode of fault failure. © 2022 The Author(s) 2022. Published by Oxford University Press on behalf of The Royal Astronomical Society. 2022 English 0956540X 10.1093/gji/ggac188 Geophysical Journal International 231 Oxford University Press 290-305 Department of Geosciences and Energy, Institute Center for Geomechanics Geofluids and Geohazards, Pennsylvania State University, University Park, PA 16802, United States; Dipartimento di Scienze della Terra, Università degli studi La Sapienza, Rome, 00185, Italy; School of Geosciences, University of Oklahoma, Norman, OK 73019, United States 1 Calcite; Earthquakes; Elasticity; Fault slips; Kaolinite; Magnesite; Magnetite; Shear flow, Effective normal stress; Fault gouge; Fault zone; Fault zone rheology; Frictional stability; Hydrological properties; Lizardite; Permeability and porosities; Rheology and friction of fault zones; Serpentinite, Friction, deformation mechanism; earthquake rupture; experimental study; fault gouge; fault slip; fault zone; friction; hydromechanics; microstructure; mineralogy; P-T conditions; permeability; phyllosilicate; porosity; rheology; serpentinite; structural control; triaxial test https://www.scopus.com/inward/record.uri?eid=2-s2.0-85133665960&doi=10.1093%2fgji%2fggac188&partnerID=40&md5=0c91d73e37b7e7e77d3535efcb102612 cited By 1 M.M. Scuderi B.M. Carpenter article Aiken2022 Serpentinization and carbonation of mantle rocks (peridotite alteration) are fundamentally important processes for a spectrum of geoscience topics, including arc volcanism, earthquake processes, chemosynthetic biological communities, and carbon sequestration. Data from a hydrophone array deployed in the Multi-Borehole Observatory (MBO) of the Oman Drilling Project demonstrates that free gas generated by peridotite alteration and/or microbial activity migrates through the formation in discrete bursts of activity. We detected several, minutes-long, swarms of gas discharge into Hole BA1B of the MBO over the course of a 9 month observation interval. The episodic nature of the migration events indicates that free gas accumulates in the permeable flow network, is pressurized, and discharges rapidly into the borehole when a critical pressure, likely associated with a capillary barrier at a flow constriction, is reached. Our observations reveal a dynamic mode of fluid migration during serpentinization, and highlight the important role that free gas can play in modulating pore pressure, fluid flow, and alteration kinetics during peridotite weathering. © 2022. The Authors. 2022 English 00948276 10.1029/2022GL100395 Geophysical Research Letters 49 John Wiley and Sons Inc Njord Centre, Departments of Physics and Geosciences, University of Oslo, Oslo, Norway; Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, MA, United States; CNRS, IRD, ISTerre, University Grenoble Alpes, Grenoble INP, University Savoie Mont Blanc, University Gustave Eiffel, Grenoble, France; School of Ocean and Earth Science, University of Southampton, Southampton, United Kingdom; Lamont Doherty Earth Observatory, Columbia University, Palisades, NY, United States 21 Acoustics; Boreholes; Flow of fluids; Gases; Groundwater; Rocks; Weathering, Arc volcanism; Earthquake process; Free gas; Gas migration; Geosciences; Mantle rocks; Peridotite alterations; Reaction-driven crackings; Serpentinization; Spectra's, Hydrogeology, borehole; earthquake; hydrogeology; hydrophone; migration; serpentinization, Oman https://www.scopus.com/inward/record.uri?eid=2-s2.0-85141938258&doi=10.1029%2f2022GL100395&partnerID=40&md5=5020b68ffc4fb4d52c7a81fd33753204 cited By 0 J.M. Aiken R.A. Sohn F. Renard J. Matter P. Kelemen B. Jamtveit article Kourim2022 The transition from the gabbroic oceanic crust to the residual mantle harzburgites of the Oman ophiolite has been drilled at Holes CM1A and CM2B (Wadi Tayin massif) during Phase 2 of the International Continental Scientific Drilling Program Oman Drilling Project (November 2017–January 2018). In order to unravel the formation processes of ultramafic rocks in the Wadi Tayin massif crust-mantle transition zone and deeper in the mantle sections beneath oceanic spreading centers, our study focuses on the whole rock major and trace element compositions (together with CO2 and H2O concentrations) of these ultramafic rocks (56 dunites and 49 harzburgites). Despite extensive serpentinization and some carbonation, most of the trace element contents (REE, HFSE, Ti, Th, U) record high temperature, magmatic process-related signatures. Two major trends are observed, with good correlations between (a) Th and U, Nb and LREE on one hand, and between (b) heavy REE, Ti and Hf on the other hand. We interpret the first trend as the signature of late melt/peridotite interactions as LREE are known to be mobilized by such processes (‘‘lithospheric process’’) and the second trend as the signature of the initial mantle partial melting (‘‘asthenospheric process’’), with little or no overprint from melt/rock reaction events. © 2022. American Geophysical Union. All Rights Reserved. 2022 English 21699313 10.1029/2021JB022694 Journal of Geophysical Research: Solid Earth 127 John Wiley and Sons Inc Institute of Earth Sciences, Academia Sinica, Taipei, Taiwan; Research Institute for Marine Geodynamics (IMG), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokosuka, Japan; Department of Earth & Planetary Sciences, University of Tennessee, Knoxville, TN, United States; Department of Geology, Faculty of Science, Niigata University, Niigata, Japan; Department of Earth Sciences, National Taiwan University, Taipei, Taiwan; Géosciences Montpellier, CNRS, Université Montpellier, Montpellier, France; Géosciences Environnement Toulouse (GET), Observatoire Midi-Pyrénées, Université de Toulouse, CNRS, IRD, Toulouse, France; Instituto Andaluz de Ciencias de la Tierra (IACT), Consejo Superior de Investigaciones Científicas, Universidad de Granada, Granada, Spain; School of Ocean & Earth Science, National Oceanography Centre Southampton, University of Southampton, Southampton, United Kingdom; Lamont–Doherty Earth Observatory, Columbia University, Palisades, NY, United States 4 crust-mantle boundary; drilling; dunite; geochemistry; harzburgite; partial melting; serpentinization; transition zone, Oman https://www.scopus.com/inward/record.uri?eid=2-s2.0-85128721983&doi=10.1029%2f2021JB022694&partnerID=40&md5=0aa7c03846c80d9ec32cf6a22d6c4288 cited By 0 F. Kourim M. Rospabé N. Dygert S. Chatterjee E. Takazawa K.-L. Wang M. Godard M. Benoit M. Giampouras K. Ishii D.A.H. Teagle M.-J. Cooper P. Kelemen article Ullmann2022 The Llanbedr (Mochras Farm) core (Wales, UK) yielded a >1300 m long mudrock sequence that has excellent potential for establishing an integrated stratigraphic scheme for the entire Early Jurassic Epoch. Lithological variations in the core are predominantly driven by hierarchical changes in the carbonate content. These changes also dominate – or may impact upon – many geochemical and physical properties of the core. The bulk carbonate C isotope record displays systematic fluctuations, the largest of which correspond to previously identified phases of environmental perturbation. The magnitudes of negative C isotope excursions in carbonate are inflated compared with equivalents previously described elsewhere as a result of diagenesis and the concomitant loss of primary carbonate. The marine macrofossil record of Mochras reveals biological and isotopic patterns that are generally comparable with other UK basins. Potentially significant differences between the Cleveland and Cardigan Bay basins are observed in the Pliensbachian and Toarcian fossils. This different expression may be related to different habitat structures or palaeoceanographic and water depth differences between these basins. Minima in macrofossil δ18 O values generally coincide with peaks in macrofossil wood abundance and sea-level lowstands inferred from sequence stratigraphic interpretation of other UK sections. This relationship suggests a possible relative sea-level control on the observed O isotope records and sediment provenance. © 2021 The Author(s). Article 2022 English 00167649 10.1144/jgs2021-018 Journal of the Geological Society 179 Geological Society of London 1 Cardigan Bay; United Kingdom; Wales; Binary alloys; Calcite; Geochemistry; Infill drilling; Isotopes; Lithology; Sea level; Stratigraphy; Bulk carbonates; Bulk rocks; Carbonate content; Drill core; Early Jurassic; Early Jurassic Epoch; Geochemicals; Isotope record; Macrofossils; Mudrocks; calcite; depositional environment; fossil; geochemistry; Jurassic; mudstone; sequence stratigraphy; Carbonation https://www.scopus.com/inward/record.uri?eid=2-s2.0-85116887216&doi=10.1144%2fjgs2021-018&partnerID=40&md5=1c7b0506dfcea2e44da5ff2e5c99007c Cited by: 2; All Open Access, Green Open Access, Hybrid Gold Open Access Clemens V. Ullmann Dominika Szűcs Mengjie Jiang Alexander J.L. Hudson Stephen P. Hesselbo article Xia2022434 Natural gas hydrate (NGH) is regarded as an important alternative future energy resource. In recent years, a few short-term production tests have been successfully conducted with both permafrost and marine sediments. However, long-term hydrate production performance and the potential geomechanical problems are not very clear. According to the available geological data at the Mallik site, a more realistic hydrate reservoir model that considers the heterogeneity of porosity, permeability, and hydrate saturation was developed and validated by reproducing the field depressurization test. The coupled multiphase and heat flow and geomechanical response induced by depressurization were fully investigated for long-term gas production from the validated hydrate reservoir model. The results indicate that long-term gas production through depressurization from a vertically heterogeneous hydrate reservoir is technically feasible, but the production efficiency is generally modest, with the low average gas production rate of 4.93 × 103 ST m3/d (ST represents the standard conditions) over a 1-year period. The hydrate dissociation region is significantly affected by the reservoir heterogeneity and reveals a heterogeneous dissociation front in the reservoir. The depressurization production results in significant increase of shear stress and vertical compaction in the hydrate reservoir. The response of shear stress indicates that the potential region of sand migration is mainly in the sand-dominant layer during gas production from the hydraulically heterogeneous hydrate reservoir (e.g., sand layers interbedded with clay layers). The maximum subsidence is approximately 78 mm and occurred at the 72nd day, whereas the final subsidence is slowly dropped to 63 mm after 1-year of depressurization production. The vertical subsidence is greatly dependent on the elastic properties and the permeability anisotropy. In particular, the maximum subsidence increased by approximately 81% when the ratio of permeability anisotropy was set at 5:1. Furthermore, the potential shear failure in the hydrate reservoir is strongly correlated to the in-situ stress state. For the normal fault stress regime, the greater the initial horizontal stress is, the less likely the hydrate reservoir is to undergo shear failure during depressurization production. Copyright © 2022 Society of Petroleum Engineers 2022 English 1086055X 10.2118/206746-PA SPE Journal 27 Society of Petroleum Engineers (SPE) 434-451 Jilin University, China 1 Anisotropy; Dissociation; Energy resources; Gas hydrates; Gases; Hydration; Petroleum deposits; Petroleum reservoir engineering; Shear stress; Submarine geology; Subsidence, Depressurizations; Gas productions; Gas-water; Multiphase gas; Natural gas hydrates; Natural gas-hydrates; Permeability anisotropy; Reservoir models; Shear failure; Water flows, Geomechanics https://www.scopus.com/inward/record.uri?eid=2-s2.0-85126098007&doi=10.2118%2f206746-PA&partnerID=40&md5=3bed2f35089b2fcf344c25532b25725b cited By 3 Y. Xia T. Xu Y. Yuan X. Xin article Frumkin2022 The southern Levant region at the fringe of the Saharan-Arabian deserts is particularly vulnerable to warming and desertification, therefore reconstruction of the hydroclimate conditions of this region during periods of past climate change provide important insight on what may occur in the future. Here we report on high temporal resolution 87Sr/86Sr, δ13C and δ18O isotope data of a stalagmite from the Har Nof cave in Jerusalem, demonstrating major climate changes during the last interglacial MIS5e between ~131–116 ka. We combine also data from other caves in Israel and the ICDP Dead Sea deep drill core. The following palaeoenvironmental history is observed: • At 131–127.5 ka, Jerusalem experienced moderate Mediterranean climate conditions. Desert dust accumulated above the cave, while salt deposition occurred in the Dead Sea. • At 127.5–122 ka, across the MIS5e insolation peak and Sapropel S5 interval in the Mediterranean, highly negative speleothem δ18O indicate both Mediterranean and southern (tropical) derived rains. Surface cover diminished, and by 122 ka the 87Sr/86Sr and δ13C values indicate complete soil removal above the cave. Very high temperatures and intensive fires caused the removal of C3 vegetation. The rainfall season shifted from winter to summer with tropical-sourced precipitation. • At 122–120.5 ka, the 87Sr/86Sr ratios indicate contributions of sea salts. Extremely high speleothem δ13C values indicate no vegetation. • At ~120.5–118 ka there was higher rainfall and lower temperatures, associated with re-establishment of vegetation, including savannah-like C4 pioneer grasses that appeared on soil patches. • At 118–116 ka, the sedimentation rate of Har Nof AF12 stalagmite is extremely low, indicating regional aridity, coinciding with massive salt deposition in the Dead Sea. © 2021 Elsevier B.V. 2022 English 00310182 10.1016/j.palaeo.2021.110761 Palaeogeography, Palaeoclimatology, Palaeoecology 586 Elsevier B.V. Institute of Earth Sciences, The Hebrew University of Jerusalem91904, Israel; Geological Survey of Israel, 32 Yesha'ayahu Leibowitz, Jerusalem, 9371234, Israel; Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY 10964, United States; Department of Earth and Environmental Sciences, Columbia University, Palisades, NY 10964, United States climate change; environmental conditions; interglacial; isotopic ratio; Last Interglacial; precipitation (climatology); rainfall; reconstruction; sedimentation; sedimentation rate; speleothem; stalagmite, Dead Sea; Israel; Jerusalem [Israel]; Levant; Mediterranean Region, Poaceae https://www.scopus.com/inward/record.uri?eid=2-s2.0-85120318066&doi=10.1016%2fj.palaeo.2021.110761&partnerID=40&md5=17badeb966dccc5b7c16125a3bb2dd8c cited By 1 A. Frumkin M. Stein S.L. Goldstein article Rodrigues2022 Article 2022 10.3389/feart.2022.888443 Frontiers in Earth Science 10 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85134526599&doi=10.3389%2ffeart.2022.888443&partnerID=40&md5=a837f8db8ba50177b8d511459a122059 Cited by: 2; All Open Access, Gold Open Access Fernanda Costa G. Rodrigues Naomi Porat Thays Desiree Mineli Ian Del Río Pontien Niyonzima Luciana Nogueira Fabiano do Nascimento Pupim Cleverson Guizan Silva Paul Baker Sherilyn Fritz Ingo Wahnfried Gustavo Kiefer André Oliveira Sawakuchi article Wang2022 The Songliao Basin in Northeast Asia is the largest and longest-lived rift basin and preserves a near-continuous continental succession of the most of the Cretaceous period, providing great material to investigate the adaption of the terrestrial systems to the Cretaceous greenhouse climate and tectonic events. However, the paucity of precise and accurate radioisotopic ages from the Early Cretaceous strata of the Songliao Basin has greatly held back the temporal and causal correlation of the continental records to the global Early Cretaceous records. Three tuff layers intercalated in the Yingcheng Formation have been intercepted by the SK-2 borehole, which offer excellent materials for radioisotopic dating and calibration of the chronostratigraphy of the Lower Cretaceous sequence of Songliao Basin. Moreover, the Yingcheng Formation recorded the largest and the last of the two major volcanic events in Songliao Basin, which also represents a turning point in the basin evolution history of Songliao from syn-rift stage to post-rift stage. Here we report high-precision U–Pb zircon geochronology by the CA-ID-TIMS technique on three tuff samples from the Yingcheng Formation of the SK-2 borehole in the Songliao Basin to construct a greatly improved, absolute age framework for the Yingcheng Formation and provide crucial age constraints for the Songliao Lower Cretaceous Strata. The new CA-ID-TIMS geochronology constrained the Yingcheng Formation at 102.571 + 0.320/−2.346 Ma to ca. 113 Ma, correlating to the Albian Stage. Combined with the previous published Songliao geochronology, the Quantou Formation is constrained to between 96.442 + 0.475/−0.086 Ma and 91.923 + 0.475/−0.086 Ma; the Denglouku Formation is constrained to between 102.571 + 0.320/−2.346 Ma and 96.442 + 0.475/−0.086 Ma; the age of the Shahezi Formation is estimated at ca. 113 Ma to ca. 118 Ma, which could extend to ca. 125 Ma in some locations in Songliao Basin. The major unconformity between the Yingcheng Formation and the Denglouku Formation, which represents the transition of the basin from syn-rift to post-rift is thus confined to between 102.571 + 0.320/−2.346 Ma and 96.442 + 0.475/−0.086 Ma. This is roughly contemporaneous with the change in the direction of the paleo-Pacific plate motion from west-southwest to north or northwest in mid-Cretaceous, suggesting their possible connections. © 2022 China University of Geosciences (Beijing) and Peking University 2022 English 16749871 10.1016/j.gsf.2022.101386 Geoscience Frontiers 13 Elsevier B.V. State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing, 100083, China; Institute of Earth Sciences, China University of Geosciences, Beijing, 100083, China; School of Earth Sciences and Resources, China University of Geosciences, Beijing, 100083, China; Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, United States; Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, 100029, China; College of Earth Sciences, Jilin University, Changchun, 130061, China; School of Ocean Sciences, China University of Geosciences, Beijing, 100083, China 4 chronostratigraphy; correlation; Cretaceous; geochronology; precision; uranium-lead dating, China; Songliao Basin https://www.scopus.com/inward/record.uri?eid=2-s2.0-85128253704&doi=10.1016%2fj.gsf.2022.101386&partnerID=40&md5=df0085c22e811b6e1d06da7c3d9b61e2 cited By 3 T. Wang C. Wang J. Ramezani X. Wan Z. Yu Y. Gao H. He H. Wu article Chunli2022555 High-resolution shallow crustal structure beneath the Songliao basin of Northeast （NE） China has obvious economic and scientific significance. To constrain the sediment and crustal structure of the Songliao basin，H-β grid search method based on wavefield downward continuation and decomposition is used with teleseismic data recorded from portable broadband seismic arrays in the NE China. The results show that the estimated sediment thickness is 0.2−2.5 km，and becomes thinner from the central depression toward the margin of the basin，with the thinnest sediment in the southwestern region. The crustal thickness varies from 24 km to 34 km，and its lateral variation correlates with the distribution of sedimentary thicknesses to a certain extent. The crustal stretching factor is calculated from the sedimentary and crustal thicknesses，with an average close to the lithospheric stretching estimation from previous receiver function studies. Thus，we infer that the thinning of the crust and lithosphere is dominated by pure shear mode during the extensional process of the Songliao basin. Moreover，the Songliao basin has a high crustal vP/vS ratio，indicating possible magmatic underplating during the lithospheric extension beneath the Songliao basin. © 2022 Acta Seismologica Sinica Press. All rights reserved. 2022 Chinese 02533782 10.11939/jass.20210108 Acta Seismologica Sinica 44 Acta Seismologica Sinica Press 555-566 Institute of Geophysics, China Earthquake Administration, Beijing, 100081, China; Key Laboratory of Seismic Observation and Geophysical Imaging, China Earthquake Administration, Beijing, 100081, China 4 broadband data; crustal structure; crustal thickness; crustal thinning; decomposition analysis; extensional tectonics; lithospheric structure; P-wave; S-wave; sediment thickness; seismic survey; teleseismic wave; wave field, China; Songliao Basin https://www.scopus.com/inward/record.uri?eid=2-s2.0-85137768878&doi=10.11939%2fjass.20210108&partnerID=40&md5=daa7dfdb62b1406a50e1058dc734e280 cited By 0 K. Chunli Z. Ruiqing C. Chengfeng L. Jiadong inproceedings trumbull2022bushveld 2022 EGU General Assembly Conference Abstracts EGU22--8339 Robert B Trumbull Ilya V Veksler Wilhelm Nikonov Dieter Rammlmair article Han20221003 2022 English 20959273 10.1016/j.scib.2022.02.008 Science Bulletin 67 Elsevier B.V. 1003-1006 College of Geoscience and Surveying Engineering, China University of Mining and Technology, Beijing, 100083, China; State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing, 100083, China; German Research Centre for Geosciences, Potsdam14473, Germany 10 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85126824312&doi=10.1016%2fj.scib.2022.02.008&partnerID=40&md5=1ad28fb40911ba9e84cece7eac85d33e cited By 4 S. Han Z. Tang C. Wang B. Horsfield T. Wang N. Mahlstedt article García-Garnica202299 Based on geochemical and magnetic susceptibility analyses, maximum warming events (hyperthermal) in the Palaeogene are recognized in the carbonate rocks of the Santa Elena borehole (SEB) in the Yucatan Peninsula, the Palaeocene-Eocene Thermal Maximum (PETM) and the Eocene Thermal Maximum 2 (ETM-2). The site records the continental shelf marine response during these global events. Major and trace element records (Al, Ba, Ca, Fe, K, Si, and Ti), Ca/Fe, Si/Al ratios, and magnetic susceptibility are used as proxies of terrigenous input, and Ba/Al ratio as a proxy of palaeoproductivity. The hyperthermal events are characterized by the dilution and/or dissolution of biogenic carbonates. The high input of terrigenous materials is linked to extreme precipitation, common during these warming events. Our records suggest a decrease in palaeoproductivity associated with a nutrients gradient in a shallow ecosystem, with deeper thermocline and stratified column water. The PETM is characterized by high eustatic sea-level conditions, with a high contribution of detrital material, indicating sedimentary condensation and marked increase in precipitation, calcite dilution and/or dissolution, and low productivity. The ETM-2 event is less extreme than the PETM, with high precipitation, although evaporation could also play an important role, as evidenced by the presence of evaporites in this interval. These changes might affect the higher trophic levels of the shelf sea ecosystem, declining productivity. The study contributes to our understanding of the global and regional effects of these past warming events and the future climate change. © 2021 John Wiley & Sons Ltd. 2022 10.1002/gj.4285 Geological Journal 57 99-113 Posgrado en Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, Ciudad de México, Mexico; Instituto de Geofísica, Universidad Nacional Autónoma de México, Ciudad de México, Mexico; Instituto de Investigación Científica y Estudios Avanzados Chicxulub, Mérida, Mexico 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85116842306&doi=10.1002%2fgj.4285&partnerID=40&md5=031388feb5ee04bfe541298f8b1a3afb cited By 0 E.M. García-Garnica L. Pérez-Cruz article Buness2022 Article 2022 10.1016/j.jappgeo.2022.104614 Journal of Applied Geophysics 200 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85126938106&doi=10.1016%2fj.jappgeo.2022.104614&partnerID=40&md5=d5ca25b176e80043e1fd0ed06efb68bb Cited by: 3; All Open Access, Hybrid Gold Open Access Hermann Buness David Colin Tanner Thomas Burschil Gerald Gabriel Ulrike Wielandt-Schuster article WOS:000864016300001 The structure of a caldera may influence its activity, making its understanding crucial for hazard assessment. Here, we analysed high-resolution seismic profiles in the Campi Flegrei (southern Italy) offshore sector. We recognised two main fault systems, including those associated with the formation of the caldera and those affecting the resurgent dome. The former system comprises three broadly concentric fault zones (inner, medial and outer ring fault zones) depicting a nested caldera geometry. Considering the relations between faults and seismic units that represent the marine and volcaniclastic successions filling the caldera, all ring faults were formed during the Campanian Ignimbrite eruption (40 ka) and subsequently reactivated during the Neapolitan Yellow Tuff eruption (15 ka). In this last caldera-forming event, the inner and medial fault zones accommodated most of the collapse and were episodically reactivated during the younger volcano-tectonic activity. The second fault system occurs in the apical zone of the resurgent dome and comprises dominantly high-angle normal faults that are mainly related to the volcano -tectonic collapse that followed the Agnano-Monte Spina Plinian eruption (4.55 ka). Finally, we provide a volcano-tectonic evolutionary model of the last 40 kyr, considering the interplay among ring and dome faults activity, volcaniclastic sedimentation, ground deformation and sea-level changes. Article 2022 10.1016/j.jsg.2022.104723 JOURNAL OF STRUCTURAL GEOLOGY 163 PERGAMON-ELSEVIER SCIENCE LTD Jacopo Natale Giovanni Camanni Luigi Ferranti Roberto Isaia Marco Sacchi Volkhard Spiess Lena Steinmann Stefano Vitale article stueken2022hydrothermal 2022 Astrobiology Mary Ann Liebert, Inc., publishers 140 Huguenot Street, 3rd Floor New~… Eva E Stüeken Kalle Kirsimäe Aivo Lepland Anthony R Prave article Yang2022 Deep earth science is the basic of deep resource exploitation, and the research on the physical and mechanical characteristics of deep rock is a research hotspot at present. In order to study the physical characteristics of deep rock at different depths, based on the cores at different depths of 4900-6830 m in Songke Well 2 (SK-2), Songliao Basin, this paper carried out the study including the rock characteristics of mineral, wave velocity, density, and pore, the variation law of physical characteristics of deep rock with depth is studied, and the relationship between different physical parameters of deep rocks is explored. It is found that the core composition minerals of SK-2 at the depth of 4900-6830 m vary greatly with the depth, in which the quality of hard phase minerals accounts for a large proportion. After entering the basement stratum, the mineral content of different phases tends to be close. With the increase of depth, the wave velocity, density, and dynamic elastic modulus of rocks show a linear increase trend, and there is a positive correlation between density and wave velocity. In the range of 4900-6830 m depth, the porosity generally shows a downward trend with the increase of depth. In the range of 6000-6830 m, the porosity tends to be close to 7% with the increase of depth, indicating that formation compaction has little impact on the development of igneous pores in this formation. There is a negative correlation between wave velocity and porosity, and the empirical formula is fitted. This study can provide a reference for the exploration of deep geoscience and deep engineering practice. © 2022 Mingqing Yang et al. Article 2022 English 14688115 10.1155/2022/6070683 Geofluids 2022 Hindawi Limited China; Songliao Basin; density; depth; experimental study; mineral; physical property; porosity; rock property; wave velocity https://www.scopus.com/inward/record.uri?eid=2-s2.0-85130575059&doi=10.1155%2f2022%2f6070683&partnerID=40&md5=431f11db0a981277ec3f6e1530cb1682 Cited by: 1; All Open Access, Gold Open Access Mingqing Yang Zhiqiang He Cong Li Bengao Yang Guikang Liu Chenghang Fu Tianyu Wang Zijie Wei inproceedings anselmetti2022drilling 2022 EGU General Assembly Conference Abstracts EGU22--3165 Flavio Anselmetti Marius Buechi article Gu2022 The Cretaceous-Paleogene (K-Pg) boundary mass extinction is commonly attributed to the Chicxulub impact and/or the Deccan Traps (DT) volcanism, but the underlying trigger remains uncertain. The lack of detailed identification of the DT eruptive pluses impedes the full assessment of their relationship to the K-Pg boundary mass extinction. Here we present the first mercury (Hg) chemostratigraphy records on the paleo Asian plate, coupled with climatic and biotic data, to constrain the effects of the DT on the Late Cretaceous climate change and mass extinction. In northern China, a total Hg (THg) spike follows warming caused by the DT volcanism and corresponds to the significant species losses. Our study suggests that this most intense pulse of the DT (~50 kyr duration) occurred just before the K-Pg boundary and suggests that it contributed to the end-Cretaceous mass extinction in northern China. © 2022 Elsevier B.V. 2022 English 09218181 10.1016/j.gloplacha.2022.103772 Global and Planetary Change 210 Elsevier B.V. State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences (Beijing), Beijing, 100083, China; School of Earth Sciences and Resources, China University of Geosciences (Beijing), Beijing, 100083, China; State Key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550002, China; Geological Survey of Canada, Calgary Natural Resources Canada, 3303 33rd Street NW, Calgary, AB T2L 2A7, Canada Boundary mass; Chemostratigraphy; Deccan trap volcanism; End-cretaceous mass extinction; Hg chemostratigraphy; Hg isotope; K-pg boundaries; Mass extinction; Northern China; Volcanic activities, Climate change, chemostratigraphy; climate change; Cretaceous; Cretaceous-Paleogene boundary; Deccan Traps; mass extinction; volcanism, China https://www.scopus.com/inward/record.uri?eid=2-s2.0-85124808935&doi=10.1016%2fj.gloplacha.2022.103772&partnerID=40&md5=bbc965d61a36b23605c587ec70291618 cited By 2 X. Gu L. Zhang R. Yin S.E. Grasby H. Yao J. Tan C. Wang article Isken2022944 Article 2022 10.1093/gji/ggac229 Geophysical Journal International 231 944 – 949 2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85135204437&doi=10.1093%2fgji%2fggac229&partnerID=40&md5=e0f5207d9c623baad96d980d36e07f9b Cited by: 12; All Open Access, Green Open Access Marius Paul Isken Hannes Vasyura-Bathke Torsten Dahm Sebastian Heimann article de2022deep 2022 Journal of Geophysical Research: Solid Earth 127 Wiley Online Library e2021JB022704 1 Juan Carlos Obeso Peter B Kelemen James M Leong Manuel D Menzel Craig E Manning Marguerite Godard Yue Cai Louise Bolge Oman Drilling Project Phase 1 Science Party article Maitituerdi2022 Sediments deposited in Lake Chala (Kenya/Tanzania) constitute a high-resolution archive of past climate and environmental change in equatorial East Africa spanning two glacial-interglacial cycles. To correctly interpret the proxy records it contains, it is crucial to understand the evolution of lacustrine sedimentation in this volcanic crater basin. Building on previous seismic stratigraphic analysis by Moernaut et al. (2010) of a dense grid of 37 km high-resolution seismic reflection profiles with up to 270 ms two-way travel time (ca. 210 m depth) of sub-bottom penetration, this study presents a seismic-based reconstruction of the complete depositional history of Lake Chala as well as a first-order age model for the major documented stages in lake evolution. The seismic stratigraphic sequence comprises 16 distinct and finely-stratified units (U1-U16, youngest to oldest), grouped into five major depositional stages. Stage I (U16, ca. 249-212 ka) marks the initiation of sedimentation in an originally ring-shaped depositional area surrounding two central tuff cones emerging from the basin floor. Stage II (U15-U12, ca. 212-114 ka) represents the onset of basinwide sedimentation above the tuff cones, implying a gradual rise in lake depth and shift to more strictly hemipelagic sedimentation. Stage III (U11-U8, ca. 114-97 ka) represents the development of a relatively flat lake floor during a period of significantly reduced lake depth. Stage IV (U7-U4, ca. 97–20.5 ka) is again characterized by largely undisturbed hemipelagic sedimentation under mostly high lake-depth conditions. Stage V (U3-U1, 20.5 ka BP to Present) represents the establishment of the present-day, very broad and flat basin floor under fluctuating lake level. Reassessing the Moernaut et al. (2010) suggestion of a minor disconformity at ca. 100 m sub-bottom depth, we here interpret this seismic feature as a thick turbidite related to a mass wasting event. Consequently we can affirm continuity of lacustrine sedimentation in the depocenter of Lake Chala throughout the past ca. 250,000 years. © 2022 Elsevier Ltd 2022 English 1464343X 10.1016/j.jafrearsci.2022.104499 Journal of African Earth Sciences 189 Elsevier Ltd Dr. Moses Strauss Department of Marine Geosciences, Leon H. Charney School of Marine Sciences, University of Haifa, Mount Carmel3498838, Israel; Renard Centre of Marine Geology (RCMG), Department of Geology, Ghent University, Krijgslaan 281/S8, Gent, B-9000, Belgium; Limnology Unit, Department of Biology, Ghent University, K. L. Ledeganckstraat 35, Gent, B-9000, Belgium deposition; environmental change; glacial-interglacial cycle; lacustrine deposit; lake; mass wasting; reconstruction; sediment; seismic stratigraphy, Kilimanjaro [Kilimanjaro (RGA)]; Kilimanjaro [Tanzania]; Tanzania https://www.scopus.com/inward/record.uri?eid=2-s2.0-85126588424&doi=10.1016%2fj.jafrearsci.2022.104499&partnerID=40&md5=8bfdaf5994bedbea5a3dbd3e36d2e5d1 cited By 3 A. Maitituerdi M. Van Daele D. Verschuren M. De Batist N. Waldmann article Zaova20221 Article 2022 10.1016/j.quaint.2022.03.002 Quaternary International 622 1 – 9 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85126326444&doi=10.1016%2fj.quaint.2022.03.002&partnerID=40&md5=e4b52e8f0ed2e1e7c8e6cd88726c0e1a Cited by: 2 Dušica Zaova Aleksandra Cvetkoska Bernd Wagner Alexander Francke Hendrik Vogel Zlatko Levkov Elena Jovanovska article Zhang20221756 A continuous sedimentary-volcanic core of Songliao Basin has been obtained through ultra-deep drilling of the SK2 borehole, which provides excellent materials for systematically investigating the formation of the Songliao Basin and the tectonic evolution history of Northeast China. In this study, we conducted a combined study of zircon U-Pb dating, whole-rock geochemical and Sr-Nd isotopic analysis on basaltic andesite samples from SK2 borehole with depths ranging from -6035m to -6084m. These SK2 basaltic andesite samples belong to Huoshiling Formation and they were formed at Early Cretaceous (141.6±1.4Ma) according to the zircon U-Pb dating results. The SK2 basaltic andesites are enriched in large ion lithophile elements, depleted in high field strength elements, and their geochemical signatures are consistent with arc magmas. These rocks show depleted Sr-Nd isotope characteristics ((87Sr/86Sr)i=0.70496~0.70478, ϵNd(t)=1.05~1.61), suggesting a depleted mantle source. In the Early Cretaceous, the evolution of Northeast China was mainly controlled by the southward subduction of the Mongol-Okhotsk oceanic plate and the western subduction of the Paleo-Pacific Plate. Previous study has shown that the subduction of Mongolia-Okhotsk Ocean induced coeval magmatism in the Great Xing'an Range, however, it is not clear whether its influence extends into the Songliao Basin. The initial subduction of Paleo-Pacific lithosphere may induce Late Mesozoic magmatism in the west of Songliao Basin. The Early Cretaceous formation and evolution of Songliao Basin were mainly affected by the activities of Mongolia Okhotsk Ocean or Paleo-Pacific lithosphere remains controversial. The Th/Hf (1.10~2.87) and Zr/Y ratios (10.1~18.7) of the SK2 basaltic andesites are similar to the within-plate basaltic magmas, we therefore suggest that SK2 samples belong to intraplate magmatism. The samples also show higher Zr, Hf and Ti contents, higher Nb/Ta ratios and more depleted Nd isotope compositions than the coeval mafic rocks in the Great Xing'an Range, indicating the SK2 samples formed in a different tectonic background. Accordingly, the Early Cretaceous volcanic rocks in Songliao Basin are most likely occurred by rollback of the subducting Paleo-Pacific Plate, while incidental lithospheric extension may promote the formation of Songliao Basin. © 2022 Science Press. All rights reserved. Article 2022 Chinese 10000569 10.18654/1000-0569/2022.06.14 Yanshi Xuebao/Acta Petrologica Sinica Science Press 1756 – 1770 6 Basalt; Binary alloys; Boreholes; Geochemistry; Geochronology; Lead alloys; Neodymium alloys; Strontium alloys; Tectonics; Uranium alloys; Zircon; Basaltic andesite; Early Cretaceous; Magmatisms; Northeast China; Okhotsk; Pacific plates; Rollback of the paleo-pacific plate; SK2 borehole; Songliao basin; Zircon U-Pb dating; Isotopes https://www.scopus.com/inward/record.uri?eid=2-s2.0-85136173338&doi=10.18654%2f1000-0569%2f2022.06.14&partnerID=40&md5=2bff93cc377823b7d57db937976523a4 Cited by: 2; All Open Access, Hybrid Gold Open Access Zhao Zhang Feng Huang Jifeng Xu Yunchuan Zeng Liying Zhang Xuli Yang Man Zhang article Mingzhong2022 Understanding in-situ stresses is the foundation for investigating deep rock mechanics. In practice, the fracture morphology of a disced core can often reflect its in-situ environment and disturbance-induced fracture process to some extent. In this study, three-dimensional dynamic scanning technology is used to reconstruct the fracture morphology of the disced cores extracted from Songke-2 as well as part of the Chinese Continental Scientific Drilling Project. The roughness of various regions of the fracture surfaces of the cores is investigated. Additionally, a parametric system is developed for the quantitative study of the integrity coefficient of the disced rock samples. Furthermore, the mechanisms and characteristics of the fractures along the stress paths are investigated. According to the findings, when shallow cores undergo discing, they have notable saddle-shaped coarse fractures, which may be related to the properties of the cores at these depths. Deep cores demonstrate discing behavior, but the generated discs are relatively thick. Deep core fracture surfaces are mostly smooth and straight, possibly propagating from the outside to the inside. Under excavation disturbance in the hydrostatic state, the extreme values of the maximum tensile stress at the core stubs show a saddle-shaped distribution. In general, the results of this study can serve as a theoretical foundation for the quantitative assessment of the intactness of disced cores. Furthermore, because disc patterns and characteristics are associated with stress states, this approach can be used to evaluate in-situ stress environments. © 2021 Elsevier Ltd 2022 English 13651609 10.1016/j.ijrmms.2021.104976 International Journal of Rock Mechanics and Mining Sciences 149 Elsevier Ltd Guangdong Provincial Key Laboratory of Deep Earth Sciences and Geothermal Energy Exploitation and Utilization, Institute of Deep Earth Sciences and Green Energy, College of Civil and Transportation Engineering, Shenzhen University, Shenzhen, 518060, China; State Key Lab. of Hydraulics and Mountain River Eng., College of Water Resource & Hydropower, Sichuan Univ., Chengdu, 610065, China; Zhensha Hydropower Construction Management Branch of Guoneng Dadu River Basin Hydropower Development Co., Ltd. LeshanSichuan 614700, China; State Key Laboratory for Geomechanics and Deep Underground Engineering, China University of Mining and Technology, 1 Daxue Road, Xuzhou, Jiangsu 221116, China Fracture; Morphology; Rock mechanics; Rocks; Stresses, Deep rocks; Discing; Fracture morphology; Fracture process; Fracture surfaces; Insitu stress; Integrity coefficient of disced rock sample; Integrity coefficients; Rock sample; Songke-2 well, Fractal dimension, fracture; in situ stress; rock mechanics; surface roughness; tensile stress https://www.scopus.com/inward/record.uri?eid=2-s2.0-85120906082&doi=10.1016%2fj.ijrmms.2021.104976&partnerID=40&md5=0f250acbc8098a85649e0f079dec7c4f cited By 53 G. Mingzhong H. Haichun X. Shouning L. Tong C. Pengfei G. Yanan X. Jing Y. Bengao X. Heping article Anselmetti202251 The sedimentary infill of glacially overdeepened valleys (i.e., structures eroded below the fluvial base level) is an excellent but yet underexplored archive with regard to the age, extent, and nature of past glaciations. The ICDP project DOVE (Drilling Overdeepened Alpine Valleys) Phase 1 investigates a series of drill cores from glacially overdeepened troughs at several locations along the northern front of the Alps. All sites will be investigated with regard to several aspects of environmental dynamics during the Quaternary, with focus on the glaciation, vegetation, and landscape history. Geophysical methods (e.g., seismic surveys), for example, will explore the geometry of overdeepened structures to better understand the process of overdeepening. Sedimentological analyses combined with downhole logging, analysis of biological remains, and state-of-the-art geochronological methods, will enable us to reconstruct the erosion and sedimentation history of the overdeepened troughs. This approach is expected to yield significant novel data quantifying the extent and timing of Middle and Late Pleistocene glaciations of the Alps. In a first phase, two sites were drilled in late 2021 into filled overdeepenings below the paleolobe of the Rhine Glacier, and both recovered a trough filling composed of multiphase glacial sequences. Fully cored Hole 5068_1_C reached a depth of 165m and recovered 10m molasse bedrock at the base. This hole will be used together with two flush holes (5068_1_A, 5068_1_B) for further geophysical cross-well experiments. Site 5068_2 reached a depth of 255m and bottomed out near the soft rock-bedrock contact. These two sites are complemented by three legacy drill sites that previously recovered filled overdeepenings below the more eastern Alpine Isar-Loisach, Salzach, and Traun paleoglacier lobes (5068_3, 5068_4, 5068_5). All analysis and interpretations of this DOVE Phase 1 will eventually lay the ground for an upcoming Phase 2 that will complete the pan-Alpine approach. This follow-up phase will investigate overdeepenings formerly occupied by paleoglacier lobes from the western and southern Alpine margins through drilling sites in France, Italy, and Slovenia. Available geological information and infrastructure make the Alps an ideal area to study overdeepened structures; however, the expected results of this study will not be restricted to the Alps. Such features are also known from other formerly glaciated mountain ranges, which are less studied than the Alps and more problematic with regards to drilling logistics. The results of this study will serve as textbook concepts to understand a full range of geological processes relevant to formerly glaciated areas all over our planet. © Copyright: 2022 English 18168957 10.5194/sd-31-51-2022 Scientific Drilling 31 Copernicus Publications 51-70 Institute of Geological Sciences, Oeschger Centre for Climate Change Research, University of Bern, Bern, 3012, Switzerland; Geological Survey of Slovenia, Ljubljana, 1000, Slovenia; Department of Geology, Université Savoie Mont Blanc, Université Grenoble Alpes, CNRS, IRD, ISTerre, Chambéry, France; Department of Civil Engineering and Natural Hazards, Institute of Applied Geology, University of Natural Resources and Life Sciences, Vienna (BOKU), Vienna, 1190, Austria; Department 1: Seismics, Gravimetry & Magnetics, Leibniz Institute for Applied Geophysics, Hanover, 30655, Germany; Institute of Geology, Leibniz University Hanover, Hanover, 30167, Germany; Institute of Earth and Environmental Sciences, University of Freiburg, Freiburg, 79104, Germany; CNR - Institute of Environmental Geology and Geoengineering (IGAG), Milan, 20126, Italy; Univ. of Geneva, Geneva, Switzerland; LIAG Hanover, Hanover, Germany; Univ. Hanover, Hanover, Germany; Univ. Bern, Bern, Switzerland; LIAG, Hanover, Germany; BGR Hanover, Hanover, Germany; ENSI, Brugg, Switzerland; Nagra, Wettingen, Switzerland; GBA, Vienna, Austria; BOKU Vienna, Vienna, Austria; Univ. Freiburg, Freiburg, Germany; Dr. von Moos AG, Gächlingen, Switzerland; ICDP-OSG, Potsdam, Germany; Eawag, Dübendorf, Switzerland; LfU, Augsburg, Germany; CNR-IGG, Padova, Italy; CNR-IGAG, Milan, Italy; Univ. Salzburg, Salzburg, Austria; ETH Zürich, Zürich, Switzerland; Univ. Leoben, Leoben, Austria; Univ. Illinois, Champaign, United States; Univ. Geneva, Geneva, Switzerland; LGRB, Freiburg, Germany Core drilling; Drills; Environmental impact; Geochronology; Glacial geology; Infill drilling; Landforms, Alpine valleys; Downholes; Drill core; Environmental dynamics; Fluvials; Geophysical methods; Phase 1; Sedimentary infill; Sedimentological analysis; Seismic surveys, Recovery https://www.scopus.com/inward/record.uri?eid=2-s2.0-85141937567&doi=10.5194%2fsd-31-51-2022&partnerID=40&md5=584a0194d41bc87e376fcf3a5277c0c2 cited By 0 F.S. Anselmetti M. Bavec C. Crouzet M. Fiebig G. Gabriel F. Preusser C. Ravazzi D. Ariztegui S. Beraus A.-C. Brandt M. Buechi H. Buness T. Burschil G. Deplazes G. Götzl G. Firla L. Gegg H.R. Graf K. Heeschen R. Kipfer E. Kroemer C. Lüthgens G. Monegato S. Neuhuber R. Pini J. Reitner B. Salcher S. Schaller C. Schmalfuss C. Schmelzbach R. Scholger B. Schuster A. Stumpf D.C. Tanner C. Thomas Y. Tomonaga U. Wieland-Schuster T. Wonik Dove Scientific Team article WOS:000812995300021 2022 10.1038/s41467-022-31049-1 NATURE COMMUNICATIONS 13 1 Manuel D. Menzel Janos L. Urai Estibalitz Ukar Greg Hirth Alexander Schwedt Andras Kovacs Lidia Kibkalo Peter B. Kelemen article Barbacka2022 Article 2022 10.1002/spp2.1425 Papers in Palaeontology 8 2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85128716742&doi=10.1002%2fspp2.1425&partnerID=40&md5=cc6c8df8d49566dd1b55395802ef4bd1 Cited by: 8; All Open Access, Green Open Access Maria Barbacka Artur Górecki Grzegorz Pacyna Grzegorz Pieńkowski Marc Philippe Károly Bóka Jadwiga Ziaja Agata Jarzynka Martin Qvarnström Grzegorz Niedźwiedzki article Pacyna2022 Article 2022 10.7306/gq.1660 Geological Quarterly 66 3 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85141794975&doi=10.7306%2fgq.1660&partnerID=40&md5=78e0ce2a705cfbf8c9ebbd8334adc356 Cited by: 6; All Open Access, Gold Open Access, Green Open Access Grzegorz Pacyna Jadwiga Ziaja Maria Barbacka Grzegorz Pieńkowski Agata Jarzynka Grzegorz Niedźwiedzki article RN256 Journal Article 2022 10.1126/science.abq5220 Science Advances 376 228-229 P. Voosen article Benito2022S23 Little is known about whether changes in lake ecosystem structure over the past 150 years are unprecedented when considering longer timescales. Similarly, research linking environmental stressors to lake ecological resilience has traditionally focused on a few sentinel sites, hindering the study of spatially synchronous changes across large areas. Here, we studied signatures of paleolimnological resilience by tracking change in diatom community composition over the last 2000 years in four Ecuadorian Andean lakes with contrasting ecoregions. We focused on climate and anthropogenic change, and the type of biological responses that these changes induced: gradual, elastic, or threshold. We combined multivariate ordination techniques with nonlinear time-series methods (hierarchical generalized additive models) to characterize trajectories of community responses in each lake, and coherence in such trajectories across lakes. We hypothesized that remote, high-elevation lakes would exhibit synchronous trends due to their shared climatic constraints, whereas lower elevation lakes would show less synchronous trends as a consequence of human density and land-cover alteration. We found that gradual and elastic responses dominated. Threshold-type responses, or regime shifts, were only detected in the less remote lake, after a long period of gradual and elastic changes. Unexpected synchrony was observed in diatom assemblages from geographically distant and human-impacted lakes, whereas lakes under similar broad-scale environmental factors (climate and ecoregion) showed asynchronous community trajectories over time. Our results reveal a complex ecological history and indicate that Andean lakes in Ecuador can gradually adapt and recover from a myriad of disturbances, exhibiting resilience over century to millennial timescales. © 2021 Association for the Sciences of Limnology and Oceanography. Article 2022 10.1002/lno.11747 Limnology and Oceanography 67 S23 – S37 S1 Ecuador; anthropogenic effect; community composition; community response; diatom; ecosystem structure; lacustrine deposit; lacustrine environment; lake ecosystem; paleolimnology; tracking; tropical environment https://www.scopus.com/inward/record.uri?eid=2-s2.0-85104123020&doi=10.1002%2flno.11747&partnerID=40&md5=e5a25104f1156f051067f3a9618eff26 Cited by: 3 Xavier Benito Melina Luethje Tobias Schneider Sherilyn C. Fritz Paul A. Baker Eric J. Pedersen Pierre Gaüzère Majoi Novaes Nascimento Mark Bush Albert Ruhi article Huber2022 The timescale of the modification stage of basin-sized impact structures is not well understood. Owing to ca. 10 km of erosion since its formation, the Vredefort impact structure, South Africa, is an ideal testing ground for deciphering post-impact modification. Here, we present geophysical and geochemical evidence from the Vredefort Granophyre Dikes, which were derived from the - now eroded - Vredefort impact melt sheet. The dikes have been studied mostly in terms of their composition, while the timing and duration of their emplacement remain controversial. We examined the modern depth extent of five dikes, with three from the inner crystalline core of the central uplift, and two from the boundary between the core and the supracrustal collar of the central uplift, using two-dimensional electrical resistivity tomography. We found that the core dikes terminate near the present erosion surface (i.e., &lt;5 m depth). In contrast, the dikes at the core-collar boundary extend to a depth ≥ 9 m. These observations suggest that the core dikes are exposed near their lowermost terminus. In addition, we obtained bulk geochemical composition of the dikes, finding that the andesitic composition phase is present in the core-collar dikes that is not found in the core dikes. The presence of this phase indicates the episodic emplacement of impact melt into subvertical crater floor fractures. We conclude that the dike formation was protracted and occurred over a time span of at least 104 years. The sequential formation of the Vredefort Granophyre Dikes points to horizontal extension of crust below the impact melt sheet above a kinematic velocity discontinuity, a crustal instability resulting from the dynamic collapse of the transient cavity. © 2021 Elsevier Inc. 2022 10.1016/j.icarus.2021.114812 Icarus 374 Department of Earth Sciences, University of the Western Cape, Robert Sobukwe Road, Bellville, 7535, South Africa; Department of Geology, University of the Free State, 205 Nelson Mandela Drive, Bloemfontein, 9300, South Africa; Institut für Geologie, Universität Hamburg, Bundesstraße 55, Hamburg, 20146, Germany; Institute for Groundwater Studies, University of the Free State, 205 Nelson Mandela Drive, Bloemfontein, 9300, South Africa https://www.scopus.com/inward/record.uri?eid=2-s2.0-85119893631&doi=10.1016%2fj.icarus.2021.114812&partnerID=40&md5=156a5e1c7822afa57711526f9dd50ca9 cited By 1 M.S. Huber E. Kovaleva M.D. Clark U. Riller F.D. Fourie article Ross2022241 Determining the nature and age of the 200-km-wide Chicxulub impact target rock is an essential step in advancing our understanding of the Maya Block basement. Few age constraints exist for the northern Maya Block crust, specifically the basement underlying the 66 Ma, 200 km-wide Chicxulub impact structure. The International Ocean Discovery Program-International Continental Scientific Drilling Program Expedition 364 core recovered a continuous section of basement rocks from the Chicxulub target rocks, which provides a unique opportunity to illuminate the pre-impact tectonic evolution of a terrane key to the development of the Gulf of Mexico. Sparse published ages for the Maya Block point to Mesoproterozoic, Ediacaran, Ordovician to Devonian crust are consistent with plate reconstruction models. In con- trast, granitic basement recovered from the Chicxulub peak ring during Expedition 364 yielded new zircon U-Pb laser ablation-in-ductively coupled plasma-mass spectrometry (LA-ICP-MS) concordant dates clustering around 334 ± 2.3 Ma. Zircon rare earth element (REE) chemistry is consistent with the granitoids having formed in a continental arc setting. Inherited zircon grains fall into three groups: 400-435 Ma, 500-635 Ma, and 940-1400 Ma, which are consistent with the incorporation of Peri-Gondwanan, PanAfrican, and Grenvillian crust, respectively. Carboniferous U-Pb ages, trace element compositions, and inherited zircon grains indicate a pre-collisional continental volcanic arc located along the Maya Block’s northern margin before NW Gondwana collided with Laurentia. The existence of a continental arc along NW Gondwana suggests southward-directed subduction of Rheic oceanic crust beneath the Maya Block and is similar to evidence for a continental arc along the northern margin of Gondwana that is documented in the Suwannee terrane, Florida, USA, and Coahuila Block of NE México. © 2022 Geological Society of America. All Rights Reserved. 2022 10.1130/B35831.1 Bulletin of the Geological Society of America 134 241-260 Department of Geological Sciences, Jackson School of Geosciences, University of Texas at Austin, 22275 Speedway Stop C9000, Austin, TX 78712, United States; Institute for Geophysics, J.J. Pickle Research Campus, Building ROC, University of Texas at Austin, 10100 Burnet Road (R2200), Austin, TX 78758, United States; Center for Planetary Systems Habitability, University of Texas at Austin, Austin, TX 78712, United States; Analytical, Environmental and Geo-Chemistry, Department of Chemistry, Vrije Universiteit Brussel, AMGC-WE-VUB, Pleinlaan 2, Brussels, 1050, Belgium; Laboratoire G-Time, Université Libre de Bruxelles, Av. F.D. Roosevelt 50, Brussels, 1050, Belgium; State Key Laboratory of Geological Processes and Mineral Resources, Planetary Science Institute, School of Earth Sciences, China University of Geosciences, Wuhan, China; State Key Laboratory of Space Science Institute, Lunar and Planetary Science, Macau University of Science and Technology, Macau, Taipa, Macau; School of Geographical and Earth Sciences, University of Glasgow, Glasgow, G12 8QQ, United Kingdom; NERC Argon Isotope Facility, Scottish Universities Environmental Research Centre (SUERC), Glasgow, United Kingdom; Center for Lunar Science and Exploration, Lunar and Planetary Institute, Houston, TX 77058, United States; Eyring Materials Center, Arizona State University, Tempe, AZ 85281, United States; Department of Earth Science and Engineering, Imperial College London, London, SW7 2AZ, United Kingdom 1-2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85109154731&doi=10.1130%2fB35831.1&partnerID=40&md5=0baa371434419788c182b46335e2c16d cited By 9 C.H. Ross D.F. Stockli C. Rasmussen S.P.S. Gulick S.J. Graaff P. Claeys J. Zhao L. Xiao A.E. Pickersgill M. Schmieder D.A. Kring A. Wittmann J.V. Morgan article cvetkoska2021pdcf In 2013 a coring campaign was carried out as part of the project Scientific Collaboration on Past Speciation Conditions in Lake Ohrid (SCOPSCO) and under the umbrella of the International Continental Scientific Drilling Program (ICDP). A 584 m sediment succession was retrieved from the central part (DEEP site) of ancient Lake Ohrid at a water depth of 243 m. The upper 446.65 mcd that represent the entire lacustrine history back to ca. 1.363 Ma contain a remarkably well-preserved record, especially of planktonic diatoms. We here present the count data of planktonic diatoms from core ICDP5045-1 spanning the period from 1.363 Ma until present. Diatom count data were generated from 350 sediment samples taken at a temporal resolution of 2.0{\textendash}4.0 ka and each slide was analysed across random transects to count 200{\textendash}400 diatom valves. 2021 10.1594/PANGAEA.934402 PANGAEA PANGAEA https://doi.org/10.1594/PANGAEA.934402 Aleksandra Cvetkoska Elena Jovanovska article Chatterjee2021170 Oxidation states within the planetary interior are intrinsically linked with the broad scale tectonism; however, it is difficult to estimate the actual oxidation conditions. Orthopyroxene-magnetite symplectite formed by olivine oxidation may provide a significant clue into such oxidation events. Here we report detailed mineralogical and petrological synthesis of such orthopyroxene-magnetite symplectites from olivine gabbros of Oman Ophiolite (Hole GT2A, ICDP Oman Drilling Project). In order to understand how oxidation affects different olivine compositions, we employed a phase equilibria approach and computed several temperature-composition diagrams at a fixed pressure (1 kbar). Our experiments predict the coexistence of olivine with Fo75-76 and Fo71 with the orthopyroxene (En79 and En76), respectively, which is remarkably similar to the mineral chemistry obtained from the Oman lower crustal gabbros. From the magnetite content, we also infer that the symplectite formation may have taken place over a range of temperatures (600-1000 °C) via subsolidus olivine oxidation and/or melt (oxidizing)-olivine interaction. The latter is more probable, considering the partial occurrence of orthopyroxene and clinopyroxene rim adjacent to the symplectites. © 2021. All Rights Reserved. 2021 English 13456296 10.2465/jmps.201130f Journal of Mineralogical and Petrological Sciences 116 Tohoku University 170-175 Department of Geology, Faculty of Science, Niigata University, Niigata, 950-2181, Japan; Department of Geology, University of North Bengal, Darjeeling, 734013, India; Department of Geology, University of Calcutta, Kolkata, 700019, India; Japan Agency for Marine-earth Science and Technology, Yokosuka, 237-0061, Japan; Graduate School of Environmental Studies, Nagoya University, Nagoya, 464-8602, Japan 3 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85111248434&doi=10.2465%2fjmps.201130f&partnerID=40&md5=c271395bb3cd26bbcfa68d7166fdb61c cited By 0 S. Chatterjee D. Bandyopadhyay E. Takazawa K. Michibayashi article Smith2021283 Palynological analysis of Site M0077A in the Chicxulub impact crater has yielded a record of the immediate Cretaceous/Paleogene (K/Pg) recovery from ground zero of the end-Cretaceous mass extinction, followed by a record of the Paleocene–Eocene Thermal Maximum (PETM) and later Ypresian (Eocene), including the Early Eocene Climatic Optimum (EECO). Eight specimens of the dinoflagellate cyst Trithyrodinium evittii have been observed near the base of the K/Pg transitional unit; these likely represent a post-impact dinoflagellate disaster recovery assemblage deposited within several days following the impact, although the possibility that some or all of the T. evittii specimens are reworked Maastrichtian cysts cannot be fully excluded. Despite high-resolution sampling of the lowermost Paleocene successions, the oldest identifiable terrestrial palynomorphs observed in the Site M0077A core, two specimens of Deltoidospora fern spores, occur at least ∼200,000 years after the impact. Other than these occurrences, the Paleocene section is nearly barren in terms of palynomorphs, likely a result of poor preservation of organic material combined with a long recovery time for vegetation in the vicinity of the crater. Pollen and fungal spore concentrations spike in an anoxic dark shale deposited during the PETM around 56 Ma, with a diverse pollen assemblage indicating the presence of a coastal shrubby tropical forest in the geographic vicinity, likely in the Yucatán Peninsula to the south. In the marine realm, this interval is characterized by thermophilic assemblages of dinoflagellate cysts. Stratigraphically constrained cluster analysis identified four statistically robust sample clusters in the lower Eocene successions, with Malvacipollis spp. and Milfordia spp. abundances driving the highest average dissimilarity between clusters. A second notable spike in palynological concentrations above the PETM section may represent another early Eocene hyperthermal event. Pollen and plant spore concentrations generally increased during the EECO, associated with increases in terrestrial input during basin infilling. © 2020 AASP–The Palynological Society. 2021 10.1080/01916122.2020.1813826 Palynology 45 283-299 Department of Geology and Geophysics, Louisiana State University, Baton Rouge, LA, United States; Museum of Natural Science, Louisiana State University, Baton Rouge, LA, United States; Department of Earth and Environmental Sciences, Division of Geology, KU Leuven, Heverlee, Belgium; Analytical, Environmental and Geochemistry (AMGC), Vrije Universiteit Brussel, Brussels, Belgium; Department of Palaeobiology, Swedish Museum of Natural History, Stockholm, Sweden; Université Lyon, UMR5023 Ecologie des Hydrosystèmes Naturels et Anthropisés, ENTPE, CNRS, Université Lyon 1, Lyon, France; Paleobotany and Paleoecology Department, Cleveland Museum of Natural History, Cleveland, OH, United States 2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85091140595&doi=10.1080%2f01916122.2020.1813826&partnerID=40&md5=4e215d80043bb69494282f7ddb2bf5b6 cited By 3 V. Smith S. Warny J. Vellekoop V. Vajda G. Escarguel D.M. Jarzen article Sun2021812 Abundant evidence from marine, ice-core and terrestrial records demonstrates that Earth’s climate has experienced co-evolution of orbital- and millennial-scale variability through the Pleistocene. The varying magnitude of millennial climate variability (MCV) was linked to orbitally paced glacial cycles over the past 800 kyr. Before this interval, global glaciations were less pronounced but more frequent, yet scarcity of a long-term integration of high-resolution continental and marine records hampers our understanding of the evolution and dynamics of MCV before the mid-Pleistocene transition. Here we present a synthesis of four centennial-resolved elemental time series, which we interpret as proxies for MCV, from North Atlantic, Iberian margin, Balkan Peninsula (Lake Ohrid) and Chinese Loess Plateau. The proxy records reveal that MCV was pervasive and persistent over the mid-latitude Northern Hemisphere during the past 1.5 Myr. Our results suggest that the magnitude of MCV is not only strongly modulated by glacial boundary conditions on Earth after the mid-Pleistocene transition, but also persistently influenced by variations in precession and obliquity through the Pleistocene. The combination of these four proxies into a new MCV stack offers a credible reference for further assessing the dynamical interactions between orbital and millennial climate variability. © 2021, The Author(s), under exclusive licence to Springer Nature Limited. Article 2021 English 17520894 10.1038/s41561-021-00794-1 Nature Geoscience 14 Nature Research 812 – 818 11 Atlantic Ocean; Atlantic Ocean (North); Balkans; China; Lake Ohrid; Loess Plateau; boundary condition; climate variation; glaciation; ice core; Northern Hemisphere; obliquity; Pleistocene https://www.scopus.com/inward/record.uri?eid=2-s2.0-85118391266&doi=10.1038%2fs41561-021-00794-1&partnerID=40&md5=c4c642cd9b2de0bb73861f6380343a09 Cited by: 26 Youbin Sun Jerry F. McManus Steven C. Clemens Xu Zhang Hendrik Vogel David A. Hodell Fei Guo Ting Wang Xingxing Liu ZhiSheng An article Salge2021207 A combined petrographic and chemical study of ejecta particles from the Cretaceous- Paleogene boundary sequence of El Guayal, Tabasco, Mexico (520 km SW of Chicxulub crater), was carried out to assess their formation conditions and genetic relation during the impact process. The reaction of silicate ejecta particles with hot volatiles during atmospheric transport may have induced alteration processes, e.g., silicification and cementation, observed in the ejecta deposits. The various microstructures of calcite ejecta particles are interpreted to reflect different thermal histories at postshock conditions. Spherulitic calcite particles may represent carbonate melts that were quenched during ejection. A recrystallized microstructure may indicate short, intense thermal stress. Various aggregates document particleparticle interactions and intermixing of components from lower silicate and upper sedimentary target lithologies. Aggregates of recrystallized calcite with silicate melt indicate the consolidation of a hot suevitic component with sediments at > 750°C. Accretionary lapilli formed in a turbulent, steam-condensing environment at ∼100°C by aggregation of solid, ash-sized particles. Concentric zones with smaller grain sizes of accreted particles indicate a recurring exchange with a hotter environment. Our results suggest that during partial ejecta plume collapse, hot silicate components were mixed with the fine fraction of local surface-derived sediments, the latter of which were displaced by the preceding ejecta curtain. These processes sustained a hot, gas-driven, lateral basal transport that was accompanied by a turbulent plume at a higher level. The exothermic back-reaction of CaO from decomposed carbonates and sulfates with CO2 to form CaCO3 may have been responsible for a prolonged release of thermal energy at a late stage of plume evolution. © 2021, The Trustees of the Natural History Museum, London. 2021 10.1130/2021.2550(08) Special Paper of the Geological Society of America 550 207-233 Natural History Museum, Imaging and Analysis Centre, Cromwell Road, London, SW7 5BD, United Kingdom; Museum für Naturkunde, Leibniz-Institut für Evolutions- und Biodiversitätsforschung, Invalidenstrasse 43, Berlin, 10115, Germany; Bruker Nano GmbH, Am Studio 2d, Berlin, 12489, Germany; Institut für Geologische Wissenschaften, Freie Universität Berlin, Malteserstraße 74-100, Berlin, 12249, Germany https://www.scopus.com/inward/record.uri?eid=2-s2.0-85126354171&doi=10.1130%2f2021.2550%2808%29&partnerID=40&md5=0d36a9723b7a22cac2d6252d738312f2 cited By 1 T. Salge R. Tagle R.-T. Schmitt L. Hecht article Yost2021 As part of the Hominin Sites and Paleolakes Drilling Project (HSPDP), phytoliths, pollen, and microcharcoal were examined from the 228 m (3.29 to 2.56 Ma) Baringo-Tugen Hills-Barsemoi drill core (BTB13). A total of 652 samples were collected at ~10 to 32 cm intervals, corresponding to sub-millennial to millennial scale temporal resolution. Microcharcoal was well-preserved throughout the core and often peaked in abundance ~5 kyr before and after insolation peaks. Phytolith preservation varied between excellent to total dissolution in alternating intervals throughout the core. Pollen was rarely preserved. These combined datasets indicate that prior to ~3.1 Ma, woody cover fluctuated between open savanna (< 40% cover), woodland (40–80% cover), and forest (> 80% cover) at typically precessional (19–23 kyr) periodicities. During the mid-Piacenzian Warm Period (MPWP; 3.26–3.01 Ma), intervals with exceptionally high microcharcoal abundance suggest that regional turnover from wooded to open habitats was driven in part by fire. After ~3.1 Ma, low-elevation woody cover likely never exceeded 40%, with oscillations between mesic tall-grass vs. xeric short-grass savanna at precessional periodicities. Mesic C4 tall-grass (Panicoideae) peaked in abundance during insolation maxima, whereas xeric C4 short-grass (Chloridoideae) peaked during insolation minima. The onset of Northern Hemisphere glaciation (NHG) at ~2.75 Ma coincided with the appearance of deep lake phases and increases in grass density and fire frequency. Spectral analysis and intervals with well-preserved phytoliths indicate that precession and interhemispheric insolation gradients influenced vegetation via their effects on equatorial precipitation and fire. This study fills a crucial gap in Pliocene vegetation reconstructions from the East African Rift Valley and its associated hominin localities. It also provides orbitally resolved regional vegetation data useful in paleodata–model comparisons for the onset of the MPWP (which is often used as an analog for future warming) and NHG. © 2020 Elsevier B.V. Article 2021 English 00310182 10.1016/j.palaeo.2020.109779 Palaeogeography, Palaeoclimatology, Palaeoecology 570 Elsevier B.V. Baringo; East African Rift; Kenya; Tugen Hills; Chloridoideae; Panicoideae; abundance; glaciation; Northern Hemisphere; phytolith; Pliocene; Pliocene-Pleistocene boundary; pollen; precipitation (climatology); savanna; woodland https://www.scopus.com/inward/record.uri?eid=2-s2.0-85085044777&doi=10.1016%2fj.palaeo.2020.109779&partnerID=40&md5=1604eeed9cad7bc8662ccdec44b66739 Cited by: 13 Chad L. Yost Sarah J. Ivory Alan L. Deino Nathan M. Rabideaux John D. Kingston Andrew S. Cohen article Guédron2021 Copper, silver, and gold exploitation has been a foundation of economic and socio-cultural development of Andean societies, at least for the last three millennia. The main centers of pre-colonial metallurgy are well-known from archeological artifacts, but temporal gaps inherent in this record handicap a finer understanding of the modalities of ore exploitation by succeeding civilizations. A continuous record over time of trace metals emitted during ore smelting operations make lake sediments excellent candidates to fill those gaps. Two millennia of metallurgy were reconstructed from atmospherically derived metals together with lead (Pb) isotope ratios in two dated sediment cores from Lake Titicaca. The first evidence for metallurgy is found during the apogee of the Tiwanaku state (AD 800–1150), with a higher copper (Cu) accumulation that can be attributed to the smelting of local Cu ores, based on Pb isotopic fingerprinting. During the Late Intermediate Period (AD 1150–1450), recorded peaks in metal deposition that persisted for ∼ twenty years show that mining activities were intensive but discontinuous. Pb isotope ratios suggest diversified extractive activities, mainly located in the southern part of the central Altiplano. Finally, the most intense mining epoch began during the Inca Empire (ca. AD 1500) and lasted until the end of the Colonial Period (AD 1830), with unprecedented metal deposition over this interval. Pb isotope fingerprinting shows that mining operations occurred mainly in the Lake Titicaca and Potosi areas and were responsible for metal emissions recorded in the entire Altiplano, as evidenced by other studies. © 2021 Elsevier Ltd Article 2021 10.1016/j.ancene.2021.100288 Anthropocene 34 South America; copper; extraction method; isotopic composition; lacustrine deposit; lead isotope; silver; trace metal https://www.scopus.com/inward/record.uri?eid=2-s2.0-85103733079&doi=10.1016%2fj.ancene.2021.100288&partnerID=40&md5=066d98529e4aa4642461e861bd854cc2 Cited by: 7; All Open Access, Green Open Access S. Guédron J. Tolu C. Delaere P. Sabatier J. Barre C. Heredia E. Brisset S. Campillo R. Bindler S.C. Fritz P.A. Baker D. Amouroux article bazargan_pressure_2021 As a petrofabric indicator, anisotropy of magnetic susceptibility (AMS) can potentially be used to infer seismic properties of rocks, and in particular seismic anisotropy. To evaluate the link between AMS and seismic anisotropy we present laboratory measurements of elastic wave velocities and anisotropy of magnetic susceptibility (AMS) for eight samples from the deep drilling investigation forming a part of the Collisional Orogeny in the Scandinavian Caledonides (COSC) project. The samples consist of a representative suite of mid crustal, deformed rock types, namely felsic and biotite-rich gneisses, and amphibolites (mafic gneisses). Compressional (P) and shear (S) waves were measured at confining pressures from room pressure to 600 MPa and temperature from room condition to 600 °C. Seismic anisotropy changes with increasing temperature and pressure, where the effect of pressure is more significant than temperature. Increasing pressure, considering the range of samples, results in an increase in mean wave speed values from 4.52 to 7.86 km/s for P waves and from 2.75 to 4.09 km/s for S waves. Biotite gneiss and amphibolite exhibit the highest anisotropy with P wave anisotropy (AVp) in the ranges of {\textasciitilde}9% to {\textasciitilde}20%, and maximum S- wave anisotropy exceeds 10%. In contrast, Felsic gneisses are significantly less anisotropic, with AVp of {\textless}7% and AVs of {\textless}6%. Up to 20% anisotropy may be generated by microcracks at 600 MPa and 600 °C, which is likely originating from thermal expansion of anisotropic minerals. An agreement is found between AMS and seismic anisotropy, although this is only a case if mean magnetic susceptibility (kmean) ranges between {\textasciitilde}1 × 10−5 to {\textasciitilde}1 × 10−3 [SI]. Such kmean values are common in rocks dominated by paramagnetic matrix minerals. Based on our results we propose that such samples are the most likely to be useful for the prediction of seismic anisotropy based on their AMS. 2021 dec en 0040-1951 10.1016/j.tecto.2021.229113 Tectonophysics 820 229113 Amphibolite, Anisotropy of magnetic susceptibility, Gneiss, Petrophysics, Scandinavian Caledonites, Seismic anisotropy https://www.sciencedirect.com/science/article/pii/S0040195121003954 Mohsen Bazargan Hem Bahadur Motra Bjarne Almqvist Sandra Piazolo Christoph Hieronymus article ask2021proposed 2021 10.1017/9781108779906.012 Cambridge University Press Maria Ask Ilmo Kukkonen Odleiv Olesen Björn Lund {\AA}ke Fagereng Jonny Rutqvist Jan-Erik Rosberg Henning Lorenz article Stoll2021 Article 2021 10.1016/j.precamres.2020.106041 Precambrian Research 354 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85098990181&doi=10.1016%2fj.precamres.2020.106041&partnerID=40&md5=fc3f25ac939ef717c0fa95df97e4922a Cited by: 8 Emily Stoll Nadja Drabon Donald R. Lowe article france2021quantifying At oceanic spreading centers, the interactions between the igneous system that builds the crust, and the hydrothermal system that cools it govern the plumbing system architecture and its thermokinetic evolution. At fast-spreading centers, most of those interactions occur around the axial magma lens (AML) that feeds the upper crust, and possibly part of the underlying mushy igneous reservoir. Heat extracted from crystallizing AML is transferred through a conductive boundary layer to the overlying hydrothermal system. Quantifying the AML physical and thermal evolutions and its interactions with hydrothermal system is therefore essential to understand oceanic accretion. Those general issues were the rationale of drilling ICDP OmanDP Hole GT3A, and we present herein the geological, structural, and petrological data that were used as a site survey to select its location. GT3 area enables observations in three dimensions of fossilized AMLs and overlying dikes. The new field data and corresponding mineral compositions are used together with thermokinetic and thermodynamic models to deliver an integrated dynamic model for the AML/hydrothermal system interactions. Results attest that the isotropic gabbro interval is composite, with gabbro bodies intruding and reheating both gabbros and dikes (up to 1,040°C). We show that AMLs should be considered as transient igneous bodies that likely crystallize from primitive MORBs in decades, releasing heat to the intruded hosts, and feeding high temperature vents on the seafloor. We show for the first time that the thermal gradient recorded in AML roof is consistent with the heat fluxes reported at active hydrothermal vents. © 2021. The Authors. 2021 English 21699313 10.1029/2020JB021496 Journal of Geophysical Research: Solid Earth 126 Wiley Online Library e2020JB021496 Université de Lorraine, CNRS, CRPG, Nancy, France; Laboratoire Magmas et Volcans, Université Clermont Auvergne - CNRS - IRD, OPGC, Aubière, France; Université de Paris, Institut de Physique du Globe de Paris, CNRS, Paris, France; Institut fuer Mineralogie, Universitaet Hannover, Hannover, Germany; Géosciences Montpellier, Université de Montpellier, CNRS, Montpellier, France; Institute of Earth Sciences, University of Lausanne, Lausanne, Switzerland 5 dike; drilling; gabbro; heat flux; hydrothermal system; hydrothermal vent; magma chamber; seafloor; spreading center; thermal evolution https://www.scopus.com/inward/record.uri?eid=2-s2.0-85106885820&doi=10.1029%2f2020JB021496&partnerID=40&md5=141a88568266015580847fc29e676407 cited By 5 Lyderic France Maéva Lombard Christian Nicollet Carole Berthod Baptiste Debret Juergen Koepke Benoit Ildefonse Aurore Toussaint article Morlock20211040 Continental and marine sediments are composed of a mixture from different sources and are influenced by a variety of environmental factors and transport processes prior to deposition. For analysis and interpretation, these sources and processes are often challenging to disentangle. We show that end-member modelling of X-ray fluorescence (XRF) core-scanning data helps to overcome these challenges by unmixing different environmental signals from high-resolution sediment geochemical records. We apply this approach to a 100 m long lacustrine succession from Lake Towuti, Indonesia, to separate the regional climate and tectonic history from local ecological and diagenetic processes. The resulting six end-members (EMs) are interpreted to represent changes in ecological (EM1), climatic (EMs 2–4), tectonic (EM 5) and geomorphic (EM6) processes determining changes in sediment composition. Because end-member analysis allows for the tracking of transient and overlapping processes, climatic changes can be followed throughout the 100 m-long succession, suggesting alternating wet and dry periods in Central Sulawesi over long (several 100 000 years) time scales. We show that end-member analysis on elemental data sets offers a detailed and objective means to disentangle depositional processes in sedimentary successions resulting from varying tectonic and environmental factors involved in sediment formation and deposition. © 2021 John Wiley & Sons, Ltd. Article 2021 English 02678179 10.1002/jqs.3338 Journal of Quaternary Science 36 John Wiley and Sons Ltd 1040 – 1051 6 Greater Sunda Islands; Lake Towuti; Malili Lakes; South Sulawesi; Sulawesi; Sunda Isles; data set; depositional environment; environmental change; geochemistry; marine sediment; Quaternary; sediment analysis; sediment transport; X-ray fluorescence https://www.scopus.com/inward/record.uri?eid=2-s2.0-85110376909&doi=10.1002%2fjqs.3338&partnerID=40&md5=176711daa48b6cea40181303e99cf223 Cited by: 4 Marina A. Morlock James M. Russell Satria Bijaksana article Yilmaz2021 The nature of sub-volcanic alteration is usually only observable after erosion and exhumation at old inactive volcanoes, via geochemical changes in hydrothermal fluids sampled at the surface, via relatively low-resolution geophysical methods or can be inferred from erupted products. These methods are spatially or temporally removed from the real subsurface and thus provide only indirect information. In contrast, the ICDP deep drilling of the Mt Unzen volcano subsurface affords a snapshot into the in situ interaction between the dacitic dykes that fed dome-forming eruptions and the sub-volcanic hydrothermal system, where the most recent lava dome eruption occurred between 1990 and 1995. Here, we analyse drill core samples from hole USDP-4, constraining their degree and type of alteration. We identify and characterize two clay alteration stages: (1) an unusual argillic alteration infill of fractured or partially dissolved plagioclase and hornblende phenocryst domains with kaolinite and Reichweite 1 illite (70)-smectite and (2) propylitic alteration of amphibole and biotite phenocrysts with the fracture-hosted precipitation of chlorite, sulfide and carbonate minerals. These observations imply that the early clay-forming fluid was acidic and probably had a magmatic component, which is indicated for the fluids related to the second chlorite-carbonate stage by our stable carbon and oxygen isotope data. The porosity in the dyke samples is dominantly fracture-hosted, and fracture-filling mineralization is common, suggesting that the dykes were fractured during magma transport, emplacement and cooling, and that subsequent permeable circulation of hydrothermal fluids led to pore clogging and potential partial sealing of the pore network on a timescale of ~ 9 years from cessation of the last eruption. These observations, in concert with evidence that intermediate, crystal-bearing magmas are susceptible to fracturing during ascent and emplacement, lead us to suggest that arc volcanoes enclosed in highly fractured country rock are susceptible to rapid hydrothermal circulation and alteration, with implications for the development of fluid flow, mineralization, stress regime and volcanic edifice structural stability. We explore these possibilities in the context of alteration at other similar volcanoes. © 2021, The Author(s). 2021 English 02588900 10.1007/s00445-021-01450-7 Bulletin of Volcanology 83 Springer Science and Business Media Deutschland GmbH Department of Earth and Environmental Sciences, Ludwig-Maximilians-Universität München (LMU), Theresienstrasse 41/III, Munich, 80333, Germany; Department of Earth Sciences, Durham University, Durham, DH1 3LE, United Kingdom; Division: Engineering Geology, Technical University of Munich (TUM), Arcisstr. 21, Munich, 80333, Germany; Grant Institute, University of Edinburgh, King’s Buildings, West Mains Road, Edinburgh, EH9 3JW, United Kingdom; Department of Earth, Ocean and Ecological Sciences, University of Liverpool, 4 Brownlow Street, Liverpool, L69 3GP, United Kingdom; Department of Geosciences, Environment and Society, Université Libre de Bruxelles, Avenue Franklin Roosevelt 50, Brussels, 1050, Belgium; National Research Institute for Earth Science and Disaster Resilience, Tennodai, Tsukuba, 305-0006, Japan 5 clay mineral; dike; emplacement; hydrothermal alteration; lava dome; permeability; porosity; volcanic arc; volcanic eruption, Japan; Kyushu; Nagasaki [Kyushu]; Unzen Volcano https://www.scopus.com/inward/record.uri?eid=2-s2.0-85104515398&doi=10.1007%2fs00445-021-01450-7&partnerID=40&md5=cdb1bd3d11057a3f3bd336fb82407912 cited By 5 T.I. Yilmaz F.B. Wadsworth H.A. Gilg K.-U. Hess J.E. Kendrick P.A. Wallace Y. Lavallée J. Utley J. Vasseur S. Nakada D.B. Dingwell article Trauth2021 Article 2021 10.1016/j.quascirev.2020.106777 Quaternary Science Reviews 266 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85108830755&doi=10.1016%2fj.quascirev.2020.106777&partnerID=40&md5=bf1e8ca9c2357ab30d976f9690539ddc Cited by: 20; All Open Access, Green Open Access Martin H. Trauth Asfawossen Asrat Andrew S. Cohen Walter Duesing Verena Foerster Stefanie Kaboth-Bahr K. Hauke Kraemer Henry F. Lamb Norbert Marwan Mark A. Maslin Frank Schäbitz article McCall2021 Hypervelocity impact cratering is an important geologic process but the rarity of large terrestrial impact craters on Earth and the limited technical options to study cratering processes in the laboratory hinders our understanding of large-scale impact processes. Drill core recovered from the peak ring of the Chicxulub impact crater during International Ocean Discovery Program (IODP)/International Continental scientific Drilling Program (ICDP) Expedition 364 provides an opportunity to examine target rock deformation and thus, to assess cratering models in this regard. Using oriented computer tomography (CT) scans and line scan images of the core, we present the orientations of mm-to-cm-scale planar cataclasite and ultracataclasite zones in the deformed granitoid target rock of the peak ring. In the upper 470 m of the target rock, the cataclasite zones dip towards the crater center, whereas the dip directions for the ultracataclasite zones are approximately tangential to the peak ring. These two orientations are consistent with deformation expected from hydrocode-modeled principal stress directions for the outward movement of rocks as the transient crater develops, and the inward movement of rocks associated with collapse of the transient crater. Near the base of the core is a 96 m-thick interval of highly-deformed target rock with impact melt rock and rock fragments not observed elsewhere in the core; this interval has previously been interpreted as an imbricate thrust zone within the peak ring. The cataclasite zones below this thrust zone have different orientations than those in the 470 m-thick block above. This observation implies a differential rotation from the overlying block during the final stages of peak-ring formation. Our results support an acoustic fluidization process, wherein blocks that vibrate or slide relative to each other allow the target rock to flow during transient crater collapse, and that the size of coherent rock blocks increases over the course of crater modification as the target rock regains its cohesive strength and acoustic fluidization decreases. © 2021 2021 10.1016/j.epsl.2021.117236 Earth and Planetary Science Letters 576 University of Texas at Austin, Jackson School of Geosciences, Institute for Geophysics, Department of Geological Sciences, J.J. Pickle Research Campus, Austin, TX 78758, United States; Center for Planetary Systems Habitability, University of Texas at Austin, Austin, TX, United States; Enthought, Inc., Austin, TX, United States; Institute of Earth and Environmental Sciences—Geology, Albert-Ludwigs Universität Freiburg, Albertstrasse 23b, Freiburg, 79110, Germany; Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EQ, United Kingdom; Institut für Geologie, Universität Hamburg, Bundesstrasse 55, Hamburg, 20146, Germany; Géosciences Montpellier, Université de Montpellier, CNRS, France; Department of Earth Science and Engineering, Imperial College LondonSW7 2AZ, United Kingdom https://www.scopus.com/inward/record.uri?eid=2-s2.0-85117124335&doi=10.1016%2fj.epsl.2021.117236&partnerID=40&md5=cd6b733a8d2a5d872b00c64c2a13f623 cited By 1 N. McCall S.P.S. Gulick A.S.P. Rae M.H. Poelchau U. Riller J. Lofi J.V. Morgan article Kuzmicheva2021795 Abstract—The formation of impact craters on the Earth’s surface is accompanied by the effect of shock waves on rocks. The shock wave compression results in rocks heating up to the point of melting and evaporation during unloading. The direct mechanical action of shock compression and residual heating change the magnetic properties of rocks. Geophysical modeling is used to determine the sources of the magnetic anomaly by interpreting the fields measured on the surface, but such modeling does not take into account the impact demagnetization of rocks. This work gives an example of analysis of the magnetic anomaly over the well-studied Bosumtwi crater (Ghana, 10.5 km diameter, 1 million years old), including the numerical modeling of the crater formation process and the construction of a magnetic anomaly model based on the simulated shock compression parameters and crater drilling data. It is shown that the morphological features of the crater— the crater rim and the central uplift—form positive magnetic anomalies around and inside the crater. © 2021, Pleiades Publishing, Ltd. Article 2021 English 10693513 10.1134/S1069351321050128 Izvestiya, Physics of the Solid Earth 57 Pleiades journals 795 – 804 5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85118729610&doi=10.1134%2fS1069351321050128&partnerID=40&md5=e74b9cd9f31164d62ed601ab671ad9d7 Cited by: 0 M. Yu. Kuzmicheva B.A. Ivanov article Friese2021 Article 2021 10.1038/s41467-021-22453-0 Nature Communications 12 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85104316745&doi=10.1038%2fs41467-021-22453-0&partnerID=40&md5=d90e3f0bf3f2ae016577ce5836e19a88 Cited by: 46; All Open Access, Gold Open Access, Green Open Access André Friese Kohen Bauer Clemens Glombitza Luis Ordoñez Daniel Ariztegui Verena B. Heuer Aurèle Vuillemin Cynthia Henny Sulung Nomosatryo Rachel Simister Dirk Wagner Satria Bijaksana Hendrik Vogel Martin Melles James M. Russell Sean A. Crowe Jens Kallmeyer inproceedings planke2021mid 2021 EGU General Assembly Conference Abstracts EGU21--15114 Sverre Planke Ritske Huismans Laurent Gernigon Stefan Buenz Jan Inge Faleide Morgan T Jones Henrik H Svensen Dougal A Jerram John M Millett others article Christeson2021 We integrate high-resolution full-waveform velocity models with seismic reflection images to map the peak ring and impactite stratigraphy at the Chicxulub structure. International Ocean Discovery Program/International Continental scientific Drilling Program Site M0077 provides ground truth for our interpretations. The peak ring is narrower (∼10 km width) where it is high relief (600–700 m below seafloor) and wider (∼15 km width) where it is lower relief (1,000–1,200 m below seafloor). Both target asymmetry and angle of impact could have contributed to observed differences in peak ring morphology. We interpret a layer of lowered velocities as a resurge layer formed from the ocean resurge, seiche, and returning tsunami flowing into the newly formed impact basin. This graded suevite layer has an average thickness of 187 ± 58 m with only local thickness differences within the annular trough, peak ring, and central basin. These observations suggest that the returning ocean was of substantial height and energetic enough to carry debris across the entire topographic peak ring. We map impact melt rock throughout the crater, with a thick impact melt sheet in the central basin (>500 m), thin intermittent melt rock capping the peak ring, and a ∼500-m thick layer of melt rock in the annular trough near the peak ring that thins toward the crater rim. We estimate that ∼70%–75% of the melt rock volume is in the central basin. We image features above and adjacent to the central basin melt sheet that we interpret as upflow zones associated with a long-lasting hydrothermal system. © 2021. American Geophysical Union. All Rights Reserved. 2021 10.1029/2021JE006938 Journal of Geophysical Research: Planets 126 Jackson School of Geosciences, Institute for Geophysics, University of Texas at Austin, Austin, TX, United States; Department of Earth Science and Engineering, Imperial College London, London, United Kingdom; Department of Geological Sciences, Jackson School of Geosciences, University of Texas at Austin, Austin, TX, United States; Center for Planetary Systems Habitability, University of Texas at Austin, Austin, TX, United States 8 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85113741472&doi=10.1029%2f2021JE006938&partnerID=40&md5=07f7d40d0fe3a17cefa6922354461584 cited By 5 G.L. Christeson J.V. Morgan S.P.S. Gulick article Li2021 The global climate during the latest Cretaceous became variable, with several global warming and cooling trends in a context of a greenhouse Earth. The responses of marine ecosystems to these climate events are relatively well known worldwide; however, lacustrine responses are poorly known due to the less frequent and discontinuous terrestrial fossil records. The relative changes in charophyte diversity in continuous lacustrine sedimentary sequences from two basins in East Asia, i.e., Songliao and Jiaolai, are considered here for the first time to establish their correlation with global climate changes during the Late Cretaceous and K/Pg boundary, compared with the well-studied south European Ibero-Armorican Island. Lacustrine deposits correlated with the Campanian–Maastrichtian Boundary Event (CMBE), related to a long cooling period provided a relatively low diversity in East Asia. In contrast, we detected a diverse charophyte flora in lacustrine deposits correlated with the Mid-Maastrichtian Event (MME) in East Asia in a global warming trend. A higher charophyte diversity was further found in the end-Cretaceous global warming event due to speciation under the background of latest Maastrichtian warming event (LMWE). During the LMWE, Characeae species such as Microchara cristata reduced its size significantly due to environmental stress probably related to the Deccan volcanism. On the other hand, a general tendency of increasing the gyrogonite size in new Characeae taxa has been detected in populations extracted from lower Danian deposits, probably related to stable palaeoenvironmental conditions in a global cooling context. This study represents the first attempt to correlate the response of the charophyte flora to global climate changes in permanent lacustrine systems during the three main Late Cretaceous–early Danian climatic turnovers. © 2020 Elsevier B.V. 2021 English 09218181 10.1016/j.gloplacha.2020.103400 Global and Planetary Change 197 Elsevier B.V. State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, 39 East Beijing Road, Nanjing, 210008, China; Nanjing Institute of Geology and Palaeontology, Centre for Excellence in Life and Paleoenvironment, Chinese Academy of Sciences, 39 East Beijing Road, Nanjing, 210008, China; Department of Geology, American University of Beirut-AUB, Beirut, 11-0236, Lebanon; Departament de Dinàmica de la Terra i de l'Oceà, Facultat de Ciències de la Terra, Institut de Recerca de la Biodiversitat (IRBio) Universitat de Barcelona-UB, Barcelona, Catalonia 08028, Spain; State Key Laboratory of Biogeology and Environmental Geology, School of Earth Sciences and Resources, China University of Geosciences, Beijing, 100083, China Deposits; Ecosystems; Global warming, Environmental stress; Global climate changes; Global climates; Lacustrine deposits; Lacustrine systems; Late cretaceous; Sedimentary sequence; Terrestrial fossils, Earth (planet), Characeae https://www.scopus.com/inward/record.uri?eid=2-s2.0-85098162872&doi=10.1016%2fj.gloplacha.2020.103400&partnerID=40&md5=ea78e8ddee096c57f2e3b9aca8c51c1e cited By 2 S. Li J. Sanjuan Q. Wang X. Wan article Xie2021701 The mechanical behavior of brittle-ductile transition in rocks is one of the essential components of deep rock mechanics, as well as a key factor that impacts the safe and efficient implementation of deep rock engineering projects.To study the differences in the mechanical behaviors of brittle-ductile transition in deep rocks, the sandstones, conglomerates and andesites at different occurrence depths (1 000-6 400 m) from the Songliao Basin are taken as research objects, and a number of conventional triaxial tests are carried out on rocks at an identical depth but under different stress levels, rocks at different depths but under an identical stress level, and rocks under different stress levels and at different depths.The brittleness characteristics of rocks are analyzed by using the pre-peak and the post-peak brittleness index.A preliminary understanding of the key influencing factors and differences in the mechanical behaviors of brittle-ductile transition in deep rocks at different depths has been achieved.The research results show that rather than an instantaneous brittle-ductile transition in rocks at different depths, a stress zone exists in progressive transition from brittleness to ductility.The brittleness of rocks at an identical depth but under different stress levels are mainly affected by the confining pressure.For sandstones at a depth of 1 600 m, its brittleness generally decreases with the increase of confining pressure, and there is a transition from its brittleness, ductility to strain hardening, its post-peak plasticity gradually increases until it shows a complete plasticity after the peak.The stress level range of 50 MPa to 70 MPa is the brittle-ductile transition zone of sandstones at the depth of 1 600 m.The brittle ductility characteristics of rocks at different depths under the same confining pressure are mainly affected by their own mineral components.For the rock samples from the Songliao Basin, their content of hard phase minerals and middle phase minerals generally increase with the increase of depths, which causes their brittleness to go up with depth increases, exhibiting a shallow to deep characteristic of transition from brittleness to ductility to brittleness.The post-peak characteristics of in-situ rock stress levels at different depths show different characteristics as the depth increases: the sandstones at depths from 1 000 m to 3 500 m depth show post-peak straining softening, post peak brittleness is found in sandstones at the depth of 4 800 m and conglomerates from depths at 5 100 m to 5 600 m, while the andesites at the depth of 6 400 m manifest the characteristic of post-peak plastic flow.Many factors affect the brittleness and ductility of rocks.Among them, game phenomenon exists in the impact on the brittleness and ductility of rocks between the mineral composition and stress environment.As the depth increases, the increase of hard phase minerals and middle phase minerals will cause the brittleness to increase, and the increase in the loading stress level will inhibit the brittleness of the rocks.The research results are expected to guide the scientific explorations and efficient implementation of the deep rock engineering. © 2021, Editorial Office of Journal of China Coal Society. All right reserved. Article 2021 Chinese 02539993 10.13225/j.cnki.jccs.YT21.0157 Meitan Xuebao/Journal of the China Coal Society 46 China Coal Society 701 – 715 3 Brittleness; Ductility; Fracture mechanics; Mineral exploration; Plasticity; Plastics industry; Rock mechanics; Rock pressure; Sandstone; Strain; Strain hardening; Stress analysis; Brittle ductile transitions; Brittle-ductile transition zone; Brittleness and ductility; Conventional triaxial test; Ductility characteristics; Efficient implementation; Key influencing factors; Scientific exploration; Minerals https://www.scopus.com/inward/record.uri?eid=2-s2.0-85104526853&doi=10.13225%2fj.cnki.jccs.YT21.0157&partnerID=40&md5=f798b7bebebb950546dd4a84ab965c3e Cited by: 29 Heping Xie Mingzhong Gao Chenghang Fu Yiqiang Lu Mingqing Yang Jianjun Hu Bengao Yang article Li2021 Review 2021 10.1016/j.earscirev.2020.103471 Earth-Science Reviews 218 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85100546662&doi=10.1016%2fj.earscirev.2020.103471&partnerID=40&md5=2b6f0c9ee34ea8027e48517d17acf89b Cited by: 50 Zhong-Quan Li Jun-Liang Chen Hao Zou Cheng-Shan Wang Qi-An Meng Heng-Lin Liu Shi-Ze Wang article Kaskes2021171 Quantitative insights into the geochemistry and petrology of proximal impactites are fundamental to understand the complex processes that affected target lithologies during and after hypervelocity impact events. Traditional analytical techniques used to obtain major- and trace-element data sets focus predominantly on either destructive whole-rock analysis or laboratory-intensive phase-specific micro-analysis. Here, we present micro–X-ray fluorescence (µXRF) as a state-of-the-art, time-efficient, and nondestructive alternative for major- and trace-element analysis for both small and large samples (up to 20 cm wide) of proximal impactites. We applied µXRF element mapping on 44 samples from the Chicxulub, Popigai, and Ries impact structures, including impact breccias, impact melt rocks, and shocked target lithologies. The µXRF mapping required limited to no sample preparation and rapidly generated high-resolution major- and trace-element maps (~1 h for 8 cm2, with a spatial resolution of 25 µm). These chemical distribution maps can be used as qualitative multi-element maps, as semiquantitative single-element heat maps, and as a basis for a novel image analysis workflow quantifying the modal abundance, size, shape, and degree of sorting of segmented components. The standardless fundamental parameters method was used to quantify the µXRF maps, and the results were compared with bulk powder techniques. Concentrations of most major elements (Na2O-CaO) were found to be accurate within 10% for thick sections. Overall, we demonstrate that μXRF is more than only a screening tool for heterogeneous impactites, because it rapidly produces bulk and phase-specific geochemical data sets that are suitable for various applications within the earth sciences. © 2021 The Authors. 2021 10.1130/2021.2550(07) Special Paper of the Geological Society of America 550 171-206 Analytical, Environmental & Geo-Chemistry Research Unit, Department of Chemistry, Vrije Universiteit Brussel (AMGC-WE-VUB), Pleinlaan 2, Brussels, 1050, Belgium; Laboratoire G-Time, Université Libre de Bruxelles, Avenue F.D. Roosevelt 50, Brussels, 1050, Belgium https://www.scopus.com/inward/record.uri?eid=2-s2.0-85111935442&doi=10.1130%2f2021.2550%2807%29&partnerID=40&md5=b8c1f8cc3ea17d0ac2f2924f20afc403 cited By 10 P. Kaskes T. Déhais S.J. Graaff S. Goderis P. Claeys article Kring2021103 Target lithologies and post-impact hydrothermal mineral assemblages in a new 1.3 km deep core from the peak ring of the Chicxulub impact crater indicate sulfate reduction was a potential energy source for a microbial ecosystem (Kring et al., 2020). That sulfate was metabolized is confirmed here by microscopic pyrite framboids with δ34S values of -5 to -35 ‰ and ΔSsulfate-sulfide values between pyrite and source sulfate of 25 to 54 ‰, which are indicative of biologic fractionation rather than inorganic fractionation processes. These data indicate the Chicxulub impact crater and its hydrothermal system hosted a subsurface microbial community in porous permeable niches within the crater's peak ring. © David A. Kring et al., 2021; Published by Mary Ann Liebert, Inc. 2021. 2021 10.1089/ast.2020.2286 Astrobiology 21 103-114 Lunar and Planetary Institute, Universities Space Research Association, 3600 Bay Area Blvd., Houston, TX 77058-1113, United States; Department of Geosciences, Swedish Museum of Natural History, Stockholm, Sweden; HNU-Neu-Ulm University of Applied Sciences, Neu-Ulm, Germany 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85099136093&doi=10.1089%2fast.2020.2286&partnerID=40&md5=8ab6220dd61a88923bebc3afc69cd434 cited By 10 D.A. Kring M.J. Whitehouse M. Schmieder article Muiruri2021315 Article 2021 10.1007/s10933-020-00173-7 Journal of Paleolimnology 65 315 – 333 3 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85100211155&doi=10.1007%2fs10933-020-00173-7&partnerID=40&md5=5fcc585c0c891b0acd8ee316a931017b Cited by: 5 Veronica M. Muiruri Richard Bernhart Owen Gijs Cort Robin W. Renaut Nathan M. Rabideaux Tim K. Lowenstein Kennie Leet Mark Sier Andrew Cohen Dan Deocampo Christopher J. Campisano Anne Billingsley Anthony Mbuthia article Huang2021 Earth's climate system is complex and inherently nonlinear, which can induce some extraneous cycles in paleoclimatic proxies at orbital time scales. The paleoenvironmental consequences of these extraneous cycles are debated owing to their complex origin. Here, we compile high-resolution datasets of total organic carbon (TOC) and stable carbon isotope (δ13Corg) datasets to investigate organic carbon burial processes in middle to high latitudes. Our results document a robust cyclicity of ∼173 thousand years (ka) in both TOC and δ13Corg. The ∼173-ka obliquity-related forcing signal was amplified by internal climate feedbacks of the carbon cycle under different geographic and climate conditions, which control a series of sensitive climatic processes. In addition, our new and compiled records from multiple proxies confirm the presence of the obliquity amplitude modulation (AM) cycle during the Mesozoic and Cenozoic and indicate the usefulness of the ∼173-ka cycle as geochronometer and for paleoclimatic interpretation. Copyright © 2021 The Authors, some rights reserved. 2021 English 23752548 10.1126/sciadv.abf9489 Science Advances 7 American Association for the Advancement of Science State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences (Beijing), Beijing, 100083, China; School of Earth Sciences and Resources, China University of Geosciences (Beijing), Beijing, 100083, China; State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Institute of Sedimentary Geology, Chengdu University of Technology, Chengdu, 610059, China; Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI 48109, United States; Leibniz Institute for Applied Geophysics, Stilleweg 2, Hannover, 30655, Germany; Department of Earth and Planetary Science, University of California, Berkeley, Berkeley, CA 94720, United States; Institute at Brown for Environment and Society, Department of Earth, Environmental and Planetary Sciences, Brown University, Providence, RI 02912, United States; School of Ocean Sciences, China University of Geosciences (Beijing), Beijing, 100083, China 28 Earth (planet); Orbits, Climate condition; Climatic process; High-resolution datasets; Internal climate; Multiple proxies; Organic carbon burial; Stable carbon isotopes; Total Organic Carbon, Organic carbon https://www.scopus.com/inward/record.uri?eid=2-s2.0-85110183512&doi=10.1126%2fsciadv.abf9489&partnerID=40&md5=226bbbfc9f5bface9eac236636301e70 cited By 18 H. Huang Y. Gao C. Ma M.M. Jones C. Zeeden D.E. Ibarra H. Wu C. Wang article Dong2021 The Songliao Basin in northeastern China is one of the largest and longest-lived Cretaceous sedimentary basins enriched in petroleum and geothermal resources worldwide. Although the modern Songliao Basin has a high geothermal gradient, the geological thermal history of the basin has not been well constrained. The SK-2 drilling program, as the second stage of the International Continental Drilling Project of Cretaceous Songliao Basin, is for recovering extensive Early Cretaceous terrestrial strata and providing valuable materials for decoding the mineralogical evolution and the paleoenvironmental changes. Here, we present whole-rock and clay mineralogical analysis on 72 core samples covering 3346–5705 m of the Shahezi Formation in the SK-2 borehole. The whole-rock minerals mainly include clay minerals, quartz, plagioclase, as well as some calcite, K-feldspar, siderite, and pyrite. The clay mineral assemblages include illite, chlorite, and illite– smectite interlayer minerals. Above 4500 m, clay minerals are dominated by illite and illite–smectite interlayers. Below 4500 m, more plagioclase, K-feldspar, and calcite are present, while illite–smectite interlayers are completely replaced by illite. The whole-rock and clay mineralogical evolution of the Shahezi Formation is primarily controlled by thermal diagenesis, although paleoenvironmental change may act as a minor contribution. Combined with published data from the Upper Cretaceous in SK-1 cores, we infer that Cretaceous greenhouse climatic and environmental changes left finger-prints on whole-rock and clay mineralogical assemblages and that the Songliao Basin reached a maximum burial depth and a peak of thermal evolution at the end of the Cretaceous. © 2021 by the authors. Licensee MDPI, Basel, Switzerland. 2021 English 2075163X 10.3390/min11101101 Minerals 11 MDPI State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences (Beijing), Beijing, 100083, China; School of Earth Science and Resources, China University of Geosciences (Beijing), Beijing, 100083, China 10 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85116579259&doi=10.3390%2fmin11101101&partnerID=40&md5=80b0d5660e3d16f8a98392728b14e948 cited By 2 T. Dong Y. Gao H. Huang X. Tian Q. Yang Y. Li L. Niu Y. Cao article Duesing2021 Article 2021 10.3389/feart.2021.594047 Frontiers in Earth Science 9 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85102883934&doi=10.3389%2ffeart.2021.594047&partnerID=40&md5=02b13457b35cbef0d6dd7d9b5ec8f9fb Cited by: 10; All Open Access, Gold Open Access, Green Open Access Walter Duesing Nadine Berner Alan L. Deino Verena Foerster K. Hauke Kraemer Norbert Marwan Martin H. Trauth article Liu2021411 2021 English 20959273 10.1016/j.scib.2020.12.002 Science Bulletin 66 Elsevier B.V. 411-413 Key Laboratory for Evolution of Past Life and Environment in Northeast Asia, Ministry of Education, Jilin University, Changchun, 130026, China; College of Earth Sciences, Jilin University, Changchun, 130061, China; Research Center of Palaeontology and Stratigraphy, Jilin University, Changchun, 130026, China; Chinese Academy of Geological Sciences, Beijing, 100037, China; College of Paleontology, Shenyang Normal University, Shenyang, 110034, China 5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85098526142&doi=10.1016%2fj.scib.2020.12.002&partnerID=40&md5=a120a5c029037ea61175c038d04588da cited By 8 H. Liu P. Wang Y. Gao H. Hou Y. Yin H. Li Y. Feng article Trauth2021 Article 2021 10.1016/j.quascirev.2021.107095 Quaternary Science Reviews 268 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85113270595&doi=10.1016%2fj.quascirev.2021.107095&partnerID=40&md5=4edccdcc48b4d5abf287b727121a7d22 Cited by: 32; All Open Access, Green Open Access Martin H. Trauth Asfawossen Asrat Nadine Berner Faysal Bibi Verena Foerster Matt Grove Stefanie Kaboth-Bahr Mark A. Maslin Manfred Mudelsee Frank Schäbitz article Schulte20212619 Core from Hole M0077 from IODP/ICDP Expedition 364 provides unprecedented evidence for the physical processes in effect during the interaction of impact melt with rock-debris-laden seawater, following a large meteorite impact into waters of the Yucatán shelf. Evidence for this interaction is based on petrographic, microstructural and chemical examination of the 46.37-m-thick impact melt rock sequence, which overlies shocked granitoid target rock of the peak ring of the Chicxulub impact structure. The melt rock sequence consists of two visually distinct phases, one is black and the other is green in colour. The black phase is aphanitic and trachyandesitic in composition and similar to melt rock from other sites within the impact structure. The green phase consists chiefly of clay minerals and sparitic calcite, which likely formed from a solidified water–rock debris mixture under hydrothermal conditions. We suggest that the layering and internal structure of the melt rock sequence resulted from a single process, i.e., violent contact of initially superheated silicate impact melt with the ocean resurge-induced water–rock mixture overriding the impact melt. Differences in density, temperature, viscosity, and velocity of this mixture and impact melt triggered Kelvin–Helmholtz and Rayleigh–Taylor instabilities at their phase boundary. As a consequence, shearing at the boundary perturbed and, thus, mingled both immiscible phases, and was accompanied by phreatomagmatic processes. These processes led to the brecciation at the top of the impact melt rock sequence. Quenching of this breccia by the seawater prevented reworking of the solidified breccia layers upon subsequent deposition of suevite. Solid-state deformation, notably in the uppermost brecciated impact melt rock layers, attests to long-term gravitational settling of the peak ring. © 2021, The Author(s). 2021 10.1007/s00531-021-02008-w International Journal of Earth Sciences 110 2619-2636 Institut Für Geologie, Universität Hamburg, Bundesstraße 55, Hamburg, 20146, Germany; Eyring Materials Center, Arizona State UniversityAZ, United States; Mineralogisch-Petrographisches Institut, Universität Hamburg, Grindelallee 48, Hamburg, 20146, Germany; Department of Earth Science and Engineering, Imperial College London, London, SW7 2AZ, United Kingdom; Institute of Geophysics and Department of Geological Sciences, University of Texas at Austin, Austin, TX 78758, United States; Center for Planetary Systems Habitability, University of Texas at Austin, Austin, TX 78712, United States; Lunar and Planetary Institute, Houston, TX 77058, United States; Department of Earth Sciences, University of Western Ontario, London, ON N6A 5B7, Canada; Institute for Earth and Space Exploration, University of Western Ontario, London, ON N6A 5B7, Canada 7 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85113794003&doi=10.1007%2fs00531-021-02008-w&partnerID=40&md5=1296ec1be952508891f64d48b100e173 cited By 4 F.M. Schulte A. Wittmann S. Jung J.V. Morgan S.P.S. Gulick D.A. Kring R.A.F. Grieve G.R. Osinski U. Riller T.J. Bralower E. Chenot G.L. Christeson P. Claeys C.S. Cockell M.J.L. Coolen L. Ferrière C. Gebhardt K. Goto S. Green H. Jones E. LeBer J. Lofi C.M. Lowery R. Ocampo-Torres L. Pérez-Cruz A.E. Pickersgill M.H. Poelchau A.S.P. Rae C. Rasmussen M. Rebolledo-Vieyra H. Sato D. Schmitt J. Smit S.M. Tikoo N. Tomioka J. Urrutia-Fucugauchi M.T. Whalen L. Xiao K.E. Yamaguchi IODP-ICDP Expedition 364 Science Party article Lu2021 Article 2021 10.1029/2021GL093391 Geophysical Research Letters 48 14 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85111502839&doi=10.1029%2f2021GL093391&partnerID=40&md5=4c22dd648eb969687a9ab6658995ef13 Cited by: 13; All Open Access, Green Open Access, Hybrid Gold Open Access Yin Lu Jasper Moernaut Nicolas Waldmann Revital Bookman G. Ian Alsop Aurélia Hubert-Ferrari Michael Strasser Amotz Agnon Shmuel Marco article Boyet2021141 Komatiites and sedimentary rocks sampled during the International Continental Drilling Program (BARB1-2–3-4–5) in the Barberton greenstone belt, South Africa, were analyzed for 146Sm-142Nd systematics. Resolved negative μ142Nd values (down to −7.7 ± 2.8) were identified in komatiites from the 3.48 Ga Komati Formation and this signature correlates with low Hf/Sm ratios measured in these samples. The negative μ142Nd point to a source with subchondritic Sm/Nd ratio which formed during the Hadean. No analytically resolvable 142Nd anomalies were measured in crustal detritus-rich, Si-rich, Ca-Fe-rich sediments and cherts from the Buck Reef (3.42 Ga) and the Fig Tree Group (3.23–3.28 Ga). Our new measurements are incorporated into a larger set of 147Sm-143Nd and 176Lu-176Hf data to better understand the 142,143Nd-176Hf isotope signatures in the mantle source at the time of komatiite crystallization. Our calculations show that the 142,143Nd-176Hf isotope signatures and Hf/Sm ratios cannot be produced by recycling into the komatiite source of detrital sediments like those sampled in the Barberton area. Only cherts have the required trace element characteristics – low Hf/Sm, radiogenic ε176Hf –but the trace element concentrations in the cherts are so low that unrealistic amounts of chert would need to be added. We propose a four-stage model for the formation of these rocks. Negative μ142Nd and low Hf/Sm ratios developed during the crystallization of a deep magma ocean soon after Earth accretion. The material that ultimately became the source of komatiites was a residual liquid produced by 50% crystallization leaving a bridgmanite/ferropericlase/Ca-perovskite cumulate. The Lu-Hf and Sm-Nd isotope systems were decoupled at this stage. After extinction of 146Sm around 4 Ga, parent/daughter ratios fractionated during a melt extraction event. With this model we explain the positive ε176Hf and slightly negative ε143Nd in these samples. The 3.55 Ga Schapenburg komatiites in another part of the Barberton belt share similar chemical signatures, supporting our model of fractionation in a deep magma ocean early in Earth's history. © 2021 Elsevier Ltd Article 2021 English 00167037 10.1016/j.gca.2021.04.020 Geochimica et Cosmochimica Acta 304 Elsevier Ltd 141 – 159 Barberton Greenstone Belt; crystallization; detrital deposit; drilling; Hadean; isotopic ratio; komatiite; magma; mantle source; neodymium isotope; samarium https://www.scopus.com/inward/record.uri?eid=2-s2.0-85107680053&doi=10.1016%2fj.gca.2021.04.020&partnerID=40&md5=e8d494597a11915e86e8f18fb0c02a90 Cited by: 9; All Open Access, Bronze Open Access, Green Open Access M. Boyet M. Garçon N. Arndt R.W. Carlson Z. Konc article Saubin20211815 The unexpected intersection of rhyolitic magma and retrieval of quenched glass particles at the Iceland Deep Drilling Project-1 geothermal well in 2009 at Krafla, Iceland, provide unprecedented opportunities to characterize the genesis, storage, and behavior of subsurface silicic magma. In this study, we analyzed the complete time series of glass particles retrieved after magma was intersected, in terms of distribution, chemistry, and vesicle textures. Detailed analysis of the particles revealed them to represent bimodal rhyolitic magma compositions and textures. Early-retrieved clear vesicular glass has higher SiO2, crystal, and vesicle contents than later-retrieved dense brown glass. The vesicle size and distribution of the brown glass also reveal several vesicle populations. The glass particles vary in δD from −120‰ to −80‰ and have dissolved water contents spanning 1.3−2 wt%, although the majority of glass particles exhibit a narrower range. Vesicular textures indicate that volatile overpressure release predominantly occurred prior to late-stage magma ascent, and we infer that vesiculation occurred in response to drilling-induced decompression. The textures and chemistry of the rhyolitic glasses are consistent with variable partial melting of host felsite. The drilling recovery sequence indicates that the clear magma (lower degree partial melt) overlays the brown magma (higher degree partial melt). The isotopes and water species support high temperature hydration of these partial melts by a mixed meteoric and magmatic composition fluid. The textural evidence for partial melting and lack of crystallization imply that magma production is ongoing, and the growing magma body thus has a high potential for geothermal energy extraction. In summary, transfer of heat and fluids into felsite triggered variable degrees of felsite partial melting and produced a hydrated rhyolite magma with chemical and textural heterogeneities that were then enhanced by drilling perturbations. Such partial melting could occur extensively in the crust above magma chambers, where complex intrusive systems can form and supply the heat and fluids required to re-melt the host rock. Our findings emphasize the need for higher resolution geophysical monitoring of restless calderas both for hazard assessment and geothermal prospecting. We also provide insight into how shallow silicic magma reacts to drilling, which could be key to future exploration of the use of magma bodies in geothermal energy. © 2021 Geological Society of America 2021 English 00167606 10.1130/B35598.1 Bulletin of the Geological Society of America 133 Geological Society of America 1815-1830 School of Earth and Environment, University of Canterbury, Christchurch, New Zealand; Lancaster Environment Centre, Lancaster University, Lancaster, United Kingdom; Department of Earth Sciences, University of Oregon, Eugene, Oregon, 97403, United States; Mineralogical Museum, Moscow, Russian Federation; Landsvirkjun National Power Company of Iceland, Reykjavik, Iceland; School of Geography, Environment and Earth Sciences, Victoria University of Wellington, New Zealand; Department of Earth Sciences, Lower Mountjoy, Durham University, Durham, DH1 3LE, United Kingdom; Earth and Planetary Sciences, University of California, Davis, California 95616, United States; Chair for Subsurface Engineering, Montanuniversität Leoben, Austria 9-10 Chemical analysis; Geothermal power plants; Geothermal prospecting; Geothermal wells; Glass; Hydration; Infill drilling; Melting; Particle size analysis; Silica; Textures, Geophysical monitoring; Glass particles; Hazard Assessment; High temperature; Higher resolution; Iceland deep drilling projects; Rhyolitic melts; Textural heterogeneities, Geothermal energy, drilling; geochemistry; glass; magma; melt; rhyolite; texture; time series analysis, Iceland; Krafla https://www.scopus.com/inward/record.uri?eid=2-s2.0-85115211895&doi=10.1130%2fB35598.1&partnerID=40&md5=e2067847ba9ba5a5510abd91a4053189 cited By 2 E. Saubin B. Kennedy H. Tuffen A.R.L. Nichols I. Bindeman A. Mortensen C.I. Schipper F.B. Wadsworth T. Watson R. Zierenberg article Somma2021 Unconventional geothermal resource development can contribute to increase power generation from renewable energy sources in countries without conventional hydrothermal reservoirs, which are usually associated with magmatic activity and extensional faulting, as well as to expand the generation in those regions where conventional resources are already used. Three recent drilling experiences focused on the characterization of unconventional resources are described and compared: the Campi Flegrei Deep Drilling Project (CFDDP) in Italy, the United Downs Deep Geothermal Power (UDDGP) project in the United Kingdom, and the DEEP Earth Energy Production in Canada. The main aspects of each project are described (geology, drilling, data collection, communication strategies) and compared to discuss challenges encountered at the tree sites considered, including a scientific drilling project (CFDDP) and two industrial ones (UDDGP and DEEP). The first project, at the first stage of pilot hole, although not reaching deep supercritical targets, showed extremely high, very rare thermal gradients even at shallow depths. Although each project has its own history, as well as social and economic context, the lessons learned at each drilling site can be used to further facilitate geothermal energy development. © 2021 by the authors. Licensee MDPI, Basel, Switzerland. Article 2021 English 19961073 10.3390/en14113306 Energies 14 MDPI AG 11 Geothermal fields; Geothermal power plants; Renewable energy resources; Resource valuation; Trees (mathematics); Communication strategy; Energy development; Energy productions; Extensional faulting; Geothermal resources; Power generation from renewable; Scientific drilling; Unconventional resources; Infill drilling https://www.scopus.com/inward/record.uri?eid=2-s2.0-85108514269&doi=10.3390%2fen14113306&partnerID=40&md5=37073f9e0e1862f8317209ce37d8db18 Cited by: 6; All Open Access, Gold Open Access, Green Open Access Renato Somma Daniela Blessent Jasmin Raymond Madeline Constance Lucy Cotton Giuseppe De Natale Alessandro Fedele Maria Jose Jurado Kirsten Marcia Mafalda Miranda Claudia Troise Thomas Wiersberg article Andreev2021 Upper Pliocene sediments from a number of fluvial outcrops in central Chukotka, northeastern Russian Arctic, along the Enmyvaam, Mechekrynnetveem, and Chanuvenvaam Rivers, have been newly studied for pollen, non-pollen-palynomorphs and, for the first time for Pliocene sediments in Eurasia, charcoals. The sediments have survived the El’gygytgyn meteorite impact event at ∼3.58 Ma. The stratigraphy of the studied outcrops suggests that the lowermost sediments were accumulated shortly before the impact event, between ∼3.60 and 3.58 Ma. At that time, coniferous forests with spruces, pines, firs, birches, larches, and alders dominated in the area. Some relatively thermophilic broad-leaved taxa (Corylus, Carpinus, Ulmus, and Myrica) might also have grown in local forests. Summer temperatures were at least 10°C warmer than today. Charcoal concentrations and composition suggest the presence of high intensity fires. Periods of rather wet climate and soil conditions are marked by common shrubby and boggy habitats with ericaceous plants and Sphagnum, and are associated with less, and probably low-intensity surface fires with less charcoal. The impact event caused widespread fires reflected by up to 4 times higher charcoal concentrations in the sediments. The sediments found above the so-called “chaotic horizon” (sediments accumulated synchronously or very shortly after the impact event) contain late Pliocene pollen assemblages comparable to those in Lake El’gygytgyn, reflecting that pine-spruce forests with some firs, birches, larches, and alder dominated in the study area. Some thermophilic taxa might also still have grown in the area. However, the age control for the sediments above the so-called chaotic horizon is poor. The uppermost sediments from the studied sections can be attributed with certainty to the Late Pleistocene and Holocene according to their stratigraphic positions and pollen assemblages. The combined pollen and charcoal analysis allowed correlating hardly datable fluvial sediments and points to varying fire regimes in warmer-than-present climates, when forest extended further north compared to today. © Copyright © 2021 Andreev, Dietze, Glushkova, Smirnov, Wennrich and Melles. 2021 English 22966463 10.3389/feart.2021.636983 Frontiers in Earth Science 9 Frontiers Media S.A. Alfred Wegener Institute, Research Unit Potsdam, Polar Terrestrial Environmental Systems, Potsdam, Germany; Institute of Geology and Mineralogy, University of Cologne, Cologne, Germany; Institute of Geology and Petroleum Technologies, Kazan Federal University, Kazan, Russian Federation; Northeastern Interdisciplinary Scientific Research Institute, Far East Branch of the Russian Academy of Sciences, Magadan, Russian Federation Charcoal; Fires; Forestry; Lakes; Meteorites; Plants (botany); Sediments; Stratigraphy, Charcoal analysis; Coniferous forests; Fluvial sediment; Meteorite impact; Pine-spruce forest; Pliocene sediments; Pollen assemblage; Summer temperature, Meteor impacts, charcoal; fluvial deposit; impact structure; meteorite; outcrop; palynology; Pliocene; sedimentary rock, Chukchi; Russian Federation https://www.scopus.com/inward/record.uri?eid=2-s2.0-85105183248&doi=10.3389%2ffeart.2021.636983&partnerID=40&md5=0140faf14a39fcd7431e044e89bcfbf3 cited By 0 A. Andreev E. Dietze O. Glushkova V. Smirnov V. Wennrich M. Melles article Haque2021 The Colorado Plateau Coring Project Phase 1 (CPCP-1) acquired three continuous drill cores from Petrified Forest National Park (PFNP), Arizona, U.S.A., two of which (CPCP-PFNP13-1A and CPCP-PFNP13-2B) intersected the Upper Triassic Chinle Formation, Lower(?)-Middle Triassic Moenkopi Formation (MF) and Permian Coconino Sandstone. We examined both cores to construct a high-resolution magnetostratigraphy of MF strata, and progressive demagnetization data yield well-defined, interpretable paleomagnetic results. Each lithostratigraphic member of the MF (Wupatki, Moqui, and Holbrook members) contains authigenic and detrital hematite as the dominant magnetic carrier with distinguishing rock magnetic characteristics. Magnetostratigraphy of MF strata in both CPCP-1 cores consists of six normal and six reverse polarity magnetozones, from the youngest to the oldest, MF1n to MF6r. Recent single-crystal chemical abrasion–thermal ionization mass spectrometry (CA-TIMS) U-Pb data from a sample in magnetozone MF1n yield a latest Anisian/earliest Ladinian (241.38 ± 0.43 Ma) age. Correlation of the CA-TIMS-calibrated magnetostratigraphy with the astronomically tuned polarity timescale for the Middle Triassic deep-marine Guandao (GD) section of South China ties the magnetozone MF1n with GD8 and MF6r with GD2r, and implies that the MF spans, at most, the earliest Anisian (Aegean) to latest Anisian (Illyrian)/earliest Ladinian stages (ca. 246.8 to 241.5 Ma). This age estimate for the MF suggests that the timespan of the regional, pre-Norian disconformity is about 17 Ma, which demonstrates that MF vertebrate fossil assemblages in east-central Arizona are millions of years (minimally 3–4 Ma) younger than previously suggested and are all Anisian in age, with no indications of substantial hiatuses in the MF section. © 2021. American Geophysical Union. All Rights Reserved. 2021 English 21699313 10.1029/2021JB021899 Journal of Geophysical Research: Solid Earth 126 John Wiley and Sons Inc Department of Geosciences, University of Texas at Dallas, Richardson, TX, United States; Department of Earth & Planetary Sciences, University of New Mexico, Albuquerque, NM, United States; Department of Geology & Geophysics, University of Utah, Salt Lake City, UT, United States; Natural History Museum of Utah, University of Utah, Salt Lake City, UT, United States; Lamont-Doherty Earth Observatory of Columbia University, Palisades, NY, United States; Earth & Planetary Sciences, Rutgers University, Piscataway, NJ, United States; Berkeley Geochronology Center, Berkeley, CA, United States; Petrified Forest National Park, Petrified Forest, AZ, United States; Institute for Geophysics, Jackson School of Geosciences, University of Texas at Austin, Austin, TX, United States; Department of Geosciences, University of Arizona, Tucson, AZ, United States 9 Anisian; biostratigraphy; demagnetization; fossil assemblage; lithostratigraphy; magnetostratigraphy; vertebrate, Arizona; China; Colorado Plateau; Petrified Forest National Park; United States, Vertebrata https://www.scopus.com/inward/record.uri?eid=2-s2.0-85115752723&doi=10.1029%2f2021JB021899&partnerID=40&md5=1e06c12cfcd306ac2d67d07bdaf1ce36 cited By 5 Z. Haque J.W. Geissman R.B. Irmis P.E. Olsen C. Lepre H. Buhedma R. Mundil W.G. Parker C. Rasmussen G.E. Gehrels article Billingsley2021 The carbon isotopic ratios of organic matter in fish fossils from diatomites and other lake beds in the HSPDP drill core from Tugen Hills, Kenya (2.56–3.29 Ma) reflect trophic resource uses and can indicate the dietary habitats of fish in the paleolake. This information offers insight into how fish communities responded to lake-level fluctuations during the Plio-Pleistocene in the East African Rift Valley. We have compared this record with fish fossil isotopes from both a previously published study of a Lake Malawi drill core (139 ka - present) and core top (modern ca 1978) samples collected at the water/sediment boundary from Lake Turkana (Kenya) of known environmental provenance. Both the Lake Malawi drill core fossils (−7.2‰ to −27.5‰ VPDB) and modern Lake Turkana samples (−16‰ to −24.6‰ VPDB) have δ13C values indicating a mix of near-shore and deep-water pelagic species. In contrast, the δ13C values for the Tugen Hills core fossils vary only between −20‰ and −27‰ VPDB. The absence of δ13C values greater than −19‰ suggests none of these fossils are derived from near-shore benthic habitats. The lack of shallow water, benthic lacustrine fish fossils through the Tugen Hills lake cycles may indicate that the rate of change from low-lake stands to deeper lake phases was very rapid, and shallow water communities were not established for long enough to leave a fish fossil record at the core site. These results strongly suggest that lake-level responses to climate variability in the Baringo Basin of the East African Rift were very abrupt during the Plio-Pleistocene transition. © 2019 Article 2021 English 00310182 10.1016/j.palaeo.2019.109466 Palaeogeography, Palaeoclimatology, Palaeoecology 570 Elsevier B.V. Baringo; East African Lakes; East African Rift; Kenya; Lake Malawi; Lake Turkana; Malawi; Tugen Hills; Turkana; carbon isotope; community structure; diatomite; environmental indicator; fossil record; organic matter; paleoenvironment; paleohydrology; sediment-water interface; trophic structure; water level https://www.scopus.com/inward/record.uri?eid=2-s2.0-85080047179&doi=10.1016%2fj.palaeo.2019.109466&partnerID=40&md5=0be9eae58f4f929f8435a9d3b87a2d5e Cited by: 1; All Open Access, Bronze Open Access Anne L. Billingsley Peter Reinthal David L. Dettman John D. Kingston Alan L. Deino Kevin Ortiz Benjamin Mohler Andrew S. Cohen article Hollaar2021 Article 2021 10.1038/s43247-021-00307-3 Communications Earth and Environment 2 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85130219929&doi=10.1038%2fs43247-021-00307-3&partnerID=40&md5=0171974f519e118fd33112d8a440121a Cited by: 28; All Open Access, Gold Open Access, Green Open Access Teuntje P. Hollaar Sarah J. Baker Stephen P. Hesselbo Jean-François Deconinck Luke Mander Micha Ruhl Claire M. Belcher article koepke2021wet 2021 Tectonophysics 817 Elsevier 229051 J Koepke ST Feig J Berndt DA Neave Oman Drilling Project Science Team others article Lupien2021 Article 2021 10.1016/j.palaeo.2019.109426 Palaeogeography, Palaeoclimatology, Palaeoecology 570 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85076830505&doi=10.1016%2fj.palaeo.2019.109426&partnerID=40&md5=639f6d980d022fa81b90426b6571229e Cited by: 23 Rachel L. Lupien James M. Russell Chad L. Yost John D. Kingston Alan L. Deino Jon Logan Anna Schuh Andrew S. Cohen article Roberts2021 Article 2021 10.1016/j.quascirev.2021.107025 Quaternary Science Reviews 266 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85109216574&doi=10.1016%2fj.quascirev.2021.107025&partnerID=40&md5=6cfaa174224afe051cee134941a2b0d6 Cited by: 21; All Open Access, Green Open Access Helen M. Roberts Christopher Bronk Ramsey Melissa S. Chapot Alan L. Deino Christine S. Lane Céline Vidal Asfawossen Asrat Andrew Cohen Verena Foerster Henry F. Lamb Frank Schäbitz Martin H. Trauth Finn A. Viehberg article Kouamelan202123 The Cretaceous interval is marked by several important geological changes whose prints are buried in both continental and marine sytems. Although significant paleoenvironmental details of this period have been inferred from biological and geochemical indicators, little is known about the physical proxies. Through scientific borehole data, petrophysical properties of Upper Cretaceous Songliao Basin (SB) in NE China and Goban Spur Basin (GSB) in NW Europe were intercorrelated to investigate the critical geological paleoenvironmental shifts and their petrophysical responses, through statistical, wavelet and spectral approaches. The results demonstrated that petrophysical features, particularly gamma-ray and resistivity reactivities, were responsive to past environmental changes in both terrestrial and marine systems. Shifts in organic-rich shale deposition and brine bearing shale showed a correlation to a probable period of seawater incursion in SB, while the gamma log, resistivity and density reactivities were interrelated to the basin paleo-structuration. At GSB, the gamma-ray and resistivity reactivities are tied-up to the Mid-Atlantic seabed motion, marine-water level shifts and paleoceanographic instabilities. In both paleo-basins, a decrease in the gamma-ray reactivity occurred from Turonian to Maastrichtian and is consistent with a regional or global increase in hydrodynamic energy. The oceanic/lacustrine anoxic events related to low sedimentation rate occurred in both basins and are associated with high gamma-ray and resistivity signals (SB); high gamma-ray and low resistivity signals (GSB). These changes correlated with geochemical evidence, suggesting that gamma-ray and resistivity can represent alternative means for marine and continental paleoenvironmental comparison. © 2021 Oxford University Press. All rights reserved. 2021 English 17422132 10.1093/jge/gxaa066 Journal of Geophysics and Engineering 18 Oxford University Press 23-46 School of Geophysics and Information Technology, China University of Geosciences, Beijing, 100083, China; Institute of Earth Sciences, China University of Geosciences, Beijing, 100083, China; School of Earth Sciences and Resources, China University of Geosciences, Beijing, 100083, China 1 Cretaceous; environmental change; facies analysis; lacustrine deposit; marine environment; marine sediment; paleoenvironment; physicochemical property; sedimentation rate, Atlantic Ocean; China; Goban Spur; Songliao Basin https://www.scopus.com/inward/record.uri?eid=2-s2.0-85127047845&doi=10.1093%2fjge%2fgxaa066&partnerID=40&md5=f3332e4f067d6179e3f66da8d18c59e5 cited By 0 K.S. Kouamelan C. Zou K.R. Assie C. Peng K.A. N'Dri O.R. Mondah article Ashwal2021bushveld 2021 Geobulletin 64 24--26 3 L Ashwal F Roelofse R Trumbull S Webb D Khoza article Rasmussen2021539 The Upper Triassic Chinle Formation is a critical non-marine archive of lowpaleolatitude biotic and environmental change in southwestern North America. The well-studied and highly fossiliferous Chinle strata at Petrified Forest National Park (PFNP), Arizona, preserve a biotic turnover event recorded by vertebrate and palynomorph fossils, which has been alternatively hypothesized to coincide with tectonically driven climate change or with the Manicouagan impact event at ca. 215.5 Ma. Previous outcrop-based geochronologic age constraints are difficult to put in an accurate stratigraphic framework because lateral facies changes and discontinuous outcrops allow for multiple interpretations. A major goal of the Colorado Plateau Coring Project (CPCP) was to retrieve a continuous record in unambiguous superposition designed to remedy this situation. We sampled the 520-m-long core 1A of the CPCP to develop an accurate age model in unquestionable superposition by combining U-Pb zircon ages and magnetostratigraphy. From 13 horizons of volcanic detritus-rich siltstone and sandstone, we screened up to ~300 zircon crystals per sample using laser ablation–inductively coupled plasma–mass spectrometry and subsequently analyzed up to 19 crystals of the youngest age population using the chemical abrasion–isotope dilution–thermal ionization mass (CA-IDTIMS) spectrometry method. These data provide new maximum depositional ages for the top of the Moenkopi Formation (ca. 241 Ma), the lower Blue Mesa Member (ca. 222 Ma), and the lower (ca. 218 to 217 Ma) and upper (ca. 213.5 Ma) Sonsela Member. The maximum depositional ages obtained for the upper Chinle Formation fall well within previously proposed age constraints, whereas the maximum depositional ages for the lower Chinle Formation are relatively younger than previously proposed ages from outcrop; however, core to outcrop stratigraphic correlations remain uncertain. By correlating our new ages with the magnetostratigraphy of the core, two feasible age model solutions can be proposed. Model 1 assumes that the youngest, coherent U-Pb age clusters of each sample are representative of the maximum depositional ages and are close to (<1 Ma difference) the true time of deposition throughout the Sonsela Member. This model suggests a significant decrease in average sediment accumulation rate in the mid-Sonsela Member. Hence, the biotic turnover preserved in the mid-Sonsela Member at PFNP is also middle Norian in age, but may, at least partially, be an artifact of a condensed section. Model 2 following the magnetostratigraphic-based age model for the CPCP core 1A suggests instead that the ages from the lower and middle Sonsela Member are inherited populations of zircon crystals that are 1–3 Ma older than the true depositional age of the strata. This results in a model in which no sudden decrease in sediment accumulation rate is necessary and implies that the base of the Sonsela Member is no older than ca. 216 Ma. Independent of these alternatives, both age models agree that none of the preserved Chinle Formation in PFNP is Carnian (>227 Ma) in age, and hence the biotic turnover event cannot be correlated to the Carnian–Norian boundary but is rather a mid-Norian event. Our age models demonstrate the powers, but also the challenges, of integrating detrital CA-ID-TIMS ages with magnetostratigraphic data to properly interpret complex sedimentary sequences. © 2020 Geological Society of America 2021 English 00167606 10.1130/B35485.1 Bulletin of the Geological Society of America 133 Geological Society of America 539-558 Department of Geology & RLS Geophysics, University of Utah, Salt Lake City, Utah 84112-0102, United States; Natural History Museum of Utah, University of Utah, Salt Lake City, Utah 84108-1214, United States; Institute for Geophysics, Jackson School of Geosciences, University of Texas at Austin, Austin, Texas 78758, United States; Berkeley Geochronology Center, Berkeley, California 94709, United States; Department of Geosciences, University of Arizona, Tucson, Arizona 85721, United States; Lamont-Doherty Earth Observatory, Columbia University, Palisades, New York 10964, United States; Department of Earth and Planetary Sciences, Rutgers University, Piscataway, New Jersey 08854, United States; Department of Geosciences, University of Texas at Dallas, Richardson, Texas 75080, United States; Department of Earth and Planetary Sciences, University of New Mexico, Albuquerque, New Mexico 87131-0001, United States; Division of Science and Resource Management, Petrified Forest National Park, Petrified Forest, Arizona 86028, United States Binary alloys; Chemical analysis; Climate change; Crystals; Deposition; Forestry; Geochronology; Inductively coupled plasma; Laser ablation; Mass spectrometers; Mass spectrometry; Silicate minerals; Stratigraphy; Zircon, Environmental change; Multiple interpretations; Paleoenvironmental change; Sediment accumulation; Sedimentary sequence; Stratigraphic correlation; Stratigraphic framework; U-pb zircon geochronologies, Lead alloys, accumulation rate; depositional environment; environmental change; geochronology; inductively coupled plasma method; magnetostratigraphy; paleoecology; paleoenvironment; stratigraphic correlation; Triassic; uranium-lead dating; zircon, Arizona; Petrified Forest National Park; United States, Vertebrata https://www.scopus.com/inward/record.uri?eid=2-s2.0-85109845370&doi=10.1130%2fB35485.1&partnerID=40&md5=1a75cd17daa2bc3bc629161cc0d643fb cited By 25 C. Rasmussen R. Mundil R.B. Irmis D. Geisler G.E. Gehrels P.E. Olsen D.V. Kent C. Lepre S.T. Kinney J.W. Geissman W.G. Parker article li_timing_2021 Recent studies in the context of the International Continental Scientific Drilling Project “Collisional Orogeny in the Scandinavian Caledonides” have focused on the importance of the Seve Nappe Complex (SNC) for understanding the subduction history of the Baltoscandian margin during closure of the Iapetus Ocean. In the classical Åre area of western central Jämtland, granulite facies migmatites and leucogranites of the Åreskutan Nappe provide evidence of Early Silurian (c. 440 Ma) high temperature metamorphism and a previous prograde, ultra-high pressure history, with microdiamonds. New LA-ICPMS zircon isotope age investigations of the underlying amphibolite facies Lower Seve Nappes, reported here, have also identified an Early Silurian tectonothermal history with pegmatitic leucogranite (c. 443 Ma) and, at lower structural levels, another felsic intrusion of earliest Middle Ordovician age (c. 469 Ma). The latter intrudes isoclinally folded host rock amphibolites and calcareous psammitic paragneisses and is itself tightly folded. Zircons in an amphibolite proved to be highly discordant but indicate Early Silurian metamorphism during isoclinal folding. Detrital zircons in a paragneiss are dominated by Sveconorwegian populations, but also include a range of younger Neoproterozoic grains down to the Early Ediacaran (c. 600 Ma). This new evidence of early Caledonian deformation and metamorphism indicates that, as farther north in the orogen, the Seve tectonothermal history in central Jämtland probably started early in the Ordovician, or before. Subduction and accretion along the Baltoscandian outer margin occurred prior to Scandian continent-continent collision, with Siluro-Devonian emplacement of the SNC across the foreland basins onto the Baltoscandian platform. 2021 jan 1103-5897 10.1080/11035897.2020.1858341 GFF 143 55--70 1 Scandinavian Caledonides, amphibolite, hf isotopes, leucogranite, lower Seve, paragneiss, u-Pb geochronology https://doi.org/10.1080/11035897.2020.1858341 Publisher: Taylor & Francis \_eprint: https://doi.org/10.1080/11035897.2020.1858341 Yuan Li David G. Gee Anna Ladenberger Håkan Sjöström article Chavarria2021770 Vertical seismic profiling (VSP) technology is increasingly being used in the fields of earthquake seismology and tectonics. This is motivated in part by the growing number of oil field microseismic monitoring surveys, but more so by projects that involve drilling deep wells for monitoring crustal activity at depth. Examples of these projects are the San Andreas Fault Observatory at Depth (SAFOD), the Nankai Trough Seismogenic Zone Experiment, the Gulf of Corinth Rift Laboratory, and the Taiwan Chelungpu Fault Drilling Project, and other projects by the International Continental and Ocean Drilling Programs (ICDP and IODP). These projects require instrumentation and surveying in deep and possibly hot borehole environments. With higher resolution than surface seismic data, images from 2D and 3D VSP data contribute to better characterization and interpretation of complex reservoirs at smaller scales. The location of receivers in the low-noise borehole environment yields higher signal-to-noise ratios, higher frequency content due to less detrimental propagation effects from the overburden, and direct correlation of data at seismic frequencies with well logs. © 2007 Society of Exploration Geophysicists. 2021 English 1070485X 10.1190/1.2748495 The Leading Edge 26 Society of Exploration Geophysicists 770-776 Paulsson Geophysical Services (P/GSI), Brea, CA, United States 6 Boreholes; Earthquakes; Monitoring; Oil fields; Oil well drilling; Tectonics, Earthquake seismology; Fault zone; Oil field microseismic monitoring surveys; Vertical seismic profiling (VSP), Seismology, borehole; fault zone; Ocean Drilling Program; oil field; San Andreas Fault; seismic data; seismology; vertical seismic profile, Gulf of Corinth; Ionian Sea; Mediterranean Sea; Nankai Trough; Pacific Ocean https://www.scopus.com/inward/record.uri?eid=2-s2.0-84995345824&doi=10.1190%2f1.2748495&partnerID=40&md5=0c7a2416381e9b7b633371c4b9911451 cited By 13 A.J. Chavarria A. Goertz M. Karrenbach B. Paulsson P. Milligan V. Soutyrine A. Hardin D. Dushman L. LaFlame inproceedings brandt2021shape 2021 EGU General Assembly Conference Abstracts EGU21--5996 Anna-Catharina Brandt David C Tanner Hermann Buness Thomas Burschil Gerald Gabriel article Bruno2021131 Investigations of how past human societies managed during times of major climate change can inform our understanding of potential human responses to ongoing environmental change. In this study, we evaluate the impact of environmental variation on human communities over the last four millennia in the southern Lake Titicaca basin of the Andes, known as Lake Wiñaymarka. Refined paleoenvironmental reconstructions from new diatom-based reconstructions of lake level together with archaeological evidence of animal and plant resource use from sites on the Taraco Peninsula, Bolivia, reveal frequent climate and lake-level changes within major cultural phases. We posit that climate fluctuations alone do not explain major past social and political transformations but instead that a highly dynamic environment contributed to the development of flexible and diverse subsistence practices by the communities in the Titicaca Basin. © 2021, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature. Article 2021 10.1007/s10745-021-00222-3 Human Ecology 49 131 – 145 2 Lake Titicaca; Peru; Bacillariophyta; archaeological evidence; climate variation; economic diversification; environmental change; Holocene; human settlement; hydrological change; lake water; nature-society relations; paleoclimate; paleoenvironment; subsistence; water level https://www.scopus.com/inward/record.uri?eid=2-s2.0-85102423996&doi=10.1007%2fs10745-021-00222-3&partnerID=40&md5=712efbaa5e9a4e620a0812e27515520c Cited by: 7 Maria C. Bruno José M. Capriles Christine A. Hastorf Sherilyn C. Fritz D. Marie Weide Alejandra I. Domic Paul A. Baker article BenDor2021 Article 2021 10.1016/j.chemgeo.2021.120261 Chemical Geology 576 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85104955540&doi=10.1016%2fj.chemgeo.2021.120261&partnerID=40&md5=995516923ec8640748325fb166657d7d Cited by: 14 Yoav Ben Dor Tomer Flax Itamar Levitan Yehouda Enzel Achim Brauer Yigal Erel article MNGADI2021104454 The presence of fault gouge and the generation of wear material between two sliding rock surfaces plays a critical role in slip weakening and propagation of ruptures along underground brittle shear fractures forming ahead of tabular excavations in deep and high stress gold mining. We performed two types of friction experiments: one with a fault gouge layer between two sliding surfaces, and the other without a fault gouge layer ‘rock-on-rock’, both under room dry conditions at slip velocities ranging from ~1.0 mm/s to 1200 mm/s. These friction experiments revealed a remarkable difference in the frictional weakening behaviour, e.g., rock-on-rock friction experiments show weakening behaviour at lower slip velocity (~5 mm/s) and generally has lower frictional strength than those with the intervening fault gouge between sliding surfaces. This study shows that the existence of the fault gouge layer between sliding rock surfaces delays the onset of fault weakening (i.e., slip weakening displacement of gouge layer experiments is larger compared to rock-on-rock experiments). It is proposed that flash heating may be the main active weakening mechanism within both our gouge and rock-on-rock experiments, and provides a feasible account for the observed weakening. The observed slip weakening displacement (Dc) differences may be attributed to the presence of a gouge layer between sliding surfaces, which has many more contacts during sliding compared to rock-on-rock experiments, thus reducing the average slip velocity per contact, consequently, the potential for activation of flash heating which delays the onset of weakening. Here we suggest that we may be able to describe brittle shear fracture rupture propagation process along underground brittle shear zones by conducting low, intermediate and high slip velocity friction experiments with and without an intervening fault gouge between sliding rock surfaces. These findings should have important implications for the modelling of rupture propagation processes in underground shear zones, a phenomenon that influences the severity of rockbursts, and hence the safety of mine workers and mining operations. 2021 1365-1609 https://doi.org/10.1016/j.ijrmms.2020.104454 International Journal of Rock Mechanics and Mining Sciences 137 104454 Shear zones, Brittle shear fracture, Rupture propagation, Severity of rockbursts, Slip velocity friction experiments, Fault weakening behaviour https://www.sciencedirect.com/science/article/pii/S1365160920308236 S.B. Mngadi A. Tsutsumi Y. Onoe M.S.D. Manzi R.J. Durrheim Y. Yabe H. Ogasawara S. Kaneki N. Wechsler A.K. Ward M. Naoi H. Moriya M. Nakatani article Nuppunen-Puputti20211 Fungi have an important role in nutrient cycling in most ecosystems on Earth, yet their ecology and functionality in deep continental subsurface remain unknown. Here, we report the first observations of active fungal colonization of mica schist in the deep continental biosphere and the ability of deep subsurface fungi to attach to rock surfaces under in situ conditions in groundwater at 500 and 967 m depth in Precambrian bedrock. We present an in situ subsurface biofilm trap, designed to reveal sessile microbial communities on rock surface in deep continental groundwater, using Outokumpu Deep Drill Hole, in eastern Finland, as a test site. The observed fungal phyla in Outokumpu subsurface were Basidiomycota, Ascomycota, and Mortierellomycota. In addition, significant proportion of the community represented unclassified Fungi. Sessile fungal communities on mica schist surfaces differed from the planktic fungal communities. The main bacterial phyla were Firmicutes, Proteobacteria, and Actinobacteriota. Biofilm formation on rock surfaces is a slow process and our results indicate that fungal and bacterial communities dominate the early surface attachment process, when pristine mineral surfaces are exposed to deep subsurface ecosystems. Various fungi showed statistically significant cross-kingdom correlation with both thiosulfate and sulfate reducing bacteria, e.g., SRB2 with fungi Debaryomyces hansenii. © 2020 by the authors. Licensee MDPI, Basel, Switzerland. Article 2021 English 20762607 10.3390/microorganisms9010064 Microorganisms 9 MDPI AG 1 – 29 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85098596898&doi=10.3390%2fmicroorganisms9010064&partnerID=40&md5=140c81e7b9749904d7730d8ee3a9dcd0 Cited by: 8; All Open Access, Gold Open Access, Green Open Access Maija Nuppunen-Puputti Riikka Kietäväinen Lotta Purkamo Pauliina Rajala Merja Itävaara Ilmo Kukkonen Malin Bomberg article Wittmann2021 Zircon is a precise chronometer and prominent recorder of impact deformation. However, many impact-induced features in zircon are poorly calibrated, sometimes due to contradicting experimental data, in other instances due to the lack of systematic studies of impact-deformed zircon. To resolve issues with the shock petrographic use of zircon, we classified impact deformation features in 429 zircon grains in a continuous drill core of uplifted, granitic bedrock in the peak ring of the 200-km-diameter K-Pg Chicxulub impact structure. Following initial identification in backscattered electron (BSE) images, Raman spectroscopy and electron backscatter diffraction confirmed one reidite-bearing zircon grain. Quartz-based shock barometry indicates the host rock of this zircon-reidite grain experienced an average shock pressure of 17.5 GPa. A survey of BSE images of 429 ZrSiO4 grains found brittle deformation features are ubiquitous, with planar fractures in one to five sets occurring in 23% of all zircon grains. Our survey also reveals a statistically significant correlation of the occurrence of planar fractures in zircon with the types of host materials. Compared to zircon enclosed in mafic, higher density mineral hosts, felsic, low-density minerals show a much higher incidence of zircon with planar fractures. This finding suggests amplification of pressure due to shock impedance contrasts between zircon and its mineral hosts. Using the impedance matching method, we modeled the shock impedance pressure amplification effect for zircon inclusions in Chicxulub granitic hosts. Our modeling indicates shock impedance could have amplified the average 17.5 GPa shock pressure in a zircon inclusion in quartz or feldspar in the Chicxulub granitic rocks to 24 ± 1 GPa, suggesting that reidite in these rocks formed between 17.5 and 25 GPa. In essence, our study of impedance-induced shock pressure amplification in zircon assemblages, including the onset of reidite formation, details how shock impedance in mineral associations can be quantified to refine shock pressure estimates. © 2021 The Author(s) 2021 10.1016/j.epsl.2021.117201 Earth and Planetary Science Letters 575 Eyring Materials Center, Arizona State University, 1001 S. McAllister Avenue, Tempe, AZ 85287-8301, United States; Space Science and Technology Centre, School of Earth and Planetary Sciences, Curtin University, GPO Box U1987, Perth, Western Australia 6845, Australia; Natural History Museum, Burgring 7, Vienna, 1010, Austria; Institute of Earth and Environmental Sciences - Geology, Albert-Ludwigs Universität Freiburg, Freiburg, Germany; Department of Earth Sciences, University of Cambridge, Cambridge, UK, United Kingdom; Institute for Geophysics, Jackson School of Geosciences, University of Texas at AustinTX 78758-4445, United States; Department of Geological Sciences, Jackson School of Geosciences, University of Texas at Austin, 22275 Speedway Stop C9000, Austin, TX 78712, United States; HNU Neu-Ulm University of Applied Sciences, Neu-Ulm, Germany; Lunar and Planetary Institute, Houston, TX, United States; State Key Laboratory of Geological Processes and Mineral Resources, Planetary Science Institute, School of Earth Sciences, China University of Geosciences, Wuhan, China; Chinese Academy of Sciences, Center for Excellence in Comparative Planetology, Hefei, 230026, China; Department of Earth Science and Engineering, Imperial College LondonUK, United Kingdom; Center for Planetary Systems Habitability, University of Texas at Austin, Austin, TX, United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-85115630556&doi=10.1016%2fj.epsl.2021.117201&partnerID=40&md5=3e515abbaab9310683e401769afc64be cited By 5 A. Wittmann A.J. Cavosie N.E. Timms L. Ferrière A. Rae C. Rasmussen C. Ross D. Stockli M. Schmieder D.A. Kring J. Zhao L. Xiao J.V. Morgan S.P.S. Gulick IODP-ICDP Expedition 364 Scientists article Martínez-Abarca20212519 Lake Chalco lies south of the Basin of Mexico and has been the subject of studies related to Late Quaternary climate variability. In 2016, the International Continental Scientific Drilling Program “MexiDrill Project” recovered a 520-m sediment record from Lake Chalco. Magnetic susceptibility measurements revealed substantial changes in sediment physical properties between 343 and 285 m depth, suggesting changes in composition associated with fluctuations in the depositional environment. We targeted sediments in the 343–285 m interval for high-resolution facies analysis, to develop a model of Lake Chalco formation. We identified three facies associations, using sediment composition, texture, mineralogy and micro-morphological characteristics: (1) detrital facies, consisting of laminated silt, massive sand, stratified silty sand, clast-supported gravel and matrix-supported gravel; (2) biogenic facies, which include diatom ooze and bivalve coquina; and (3) volcaniclastic facies, represented by clast-supported pumice deposits. We propose that formation of Lake Chalco occurred in four stages, which we identified by changes in sediment characteristics. The first stage was an alluvial delta environment, in which debris and hyper-concentrated flows were the main sediment transport agents. The second was characterized by turbulent flows in a fluvial deltaic environment, which alternated with laminar flows associated with floodplains. The third stage was a time of fluvio-lacustrine transition in the basin, with formation of the previously identified Paleo-Chalco-I Lake, in response to wet conditions. During the fourth stage, a deep eutrophic lake formed (Paleo-Chalco-II), with an origin that appears to have been related to regional volcanism. Our working age-depth model indicates establishment of the lake at ca. 400 ± 46 ka. This paper presents the only available record of the transition from alluvial to lacustrine sedimentation of Lake Chalco. Our results allow us to establish (1) how the lake was formed and what the phases of its development were, (2) how a major volcanic event altered and transformed the lacustrine sedimentation, and (3) which climatic conditions dominated during the lake formation. The age for the onset of the lacustrine sedimentation in Chalco is for the first time constrained to around 400 ka. This enables to expand our knowledge of the climate for a time for which there is no information from terrestrial records of tropical North America. © 2021, Geologische Vereinigung e.V. (GV). 2021 English 14373254 10.1007/s00531-020-01964-z International Journal of Earth Sciences 110 Springer Science and Business Media Deutschland GmbH 2519-2539 Posgrado en Ciencias de La Tierra, Universidad Nacional Autónoma de México, Mexico City, CP. 04510, Mexico; Instituto de Geofísica, Universidad Nacional Autónoma de México, Mexico City, CP. 04510, Mexico; Instituto de Geología, Universidad Nacional Autónoma de México, Mexico City, CP. 04510, Mexico; Instituto Pirenaico de Ecología – CSIC, Apdo 13034, Zaragoza, 50080, Spain; Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, United States; Large Lakes Observatory & Dept. of Earth and Environmental Sciences, University of Minnesota Duluth, Duluth, MN 55812, United States; School of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom 7 climate conditions; climate variation; depositional environment; facies analysis; fluvial deposit; lacustrine deposit; Quaternary; sedimentation; stratigraphy; volcanism, Lake Chalco; Mexico [North America]; Valley of Mexico, Bacillariophyta; Bivalvia https://www.scopus.com/inward/record.uri?eid=2-s2.0-85099255072&doi=10.1007%2fs00531-020-01964-z&partnerID=40&md5=c4212c41d77b885c8ae5f3d9e52b327d cited By 5 R. Martínez-Abarca B. Ortega-Guerrero S. Lozano-García M. Caballero B. Valero-Garcés D. McGee E.T. Brown M. Stockhecke A.G.E. Hodgetts article sayyadi2021seismic 2021 10.1007/s00445-021-01481-0 Bulletin of Volcanology 83 Springer 1--14 8 Sara Sayyadi Páll Einarsson Magnus T Gudmundsson article almqvist_seismic_2021 We report compositional, microstructural and seismic properties from 24 samples collected from the Middle Allochthon (Seve Nappe) of the central Scandinavian Caledonides, and its bounding shear zones. The samples stem both from field outcrops and the continental drilling project COSC-1 and include quartzofeldspathic gneisses, hornblende gneisses, amphibolites, marbles, calc-silicates, quartzites and mica schists, of medium to high-strain. Seismic velocities and anisotropy of P (AVp) and S (AVs) waves of these samples were calculated using microstructural and crystal preferred orientation data obtained from Electron Backscatter Diffraction analysis (EBSD). Mica-schist exhibits the highest anisotropy (AVP {\textasciitilde} 31%; max AVs {\textasciitilde}34%), followed by hornblende-dominated rocks (AVp {\textasciitilde}5–13%; max AVs 5–10%) and quartzites (AVp {\textasciitilde}6.5–10.5%; max AVs {\textasciitilde}7.5–12%). Lowest anisotropy is found in calc-silicate rocks (AVp {\textasciitilde}4%; max AVs 3–4%), where the symmetry of anisotropy is more complex due to the contribution to anisotropy from several phases. Anisotropy is attributed to: 1) modal mineral composition, in particular mica and amphibole content, 2) CPO intensity, 3) crystallization of anisotropic minerals from fluids circulating in the shear zone (calc-silicates and amphibolites), and to a lesser extent 4) compositional banding of minerals with contrasting elastic properties and density. Our results link observed anisotropy to the rock composition and strain in a representative section across the Central Scandinavian Caledonides and indicate that the entire Seve Nappe is seismically anisotropic. Strain has partitioned on the nappe scale, and likely on the microstructural scale. High- strain shear zones that develop at boundaries of the allochthon and internally within the allochthon show higher anisotropy than a more moderately strained interior of the nappe. The Seve Nappe may be considered as a template for deforming, ductile and flowing middle crust, which is in line with general observations of seismic anisotropy in mid-crustal settings. 2021 nov en 0040-1951 10.1016/j.tecto.2021.229045 Tectonophysics 819 229045 Strain, Seismic anisotropy, Shear zone, Scandinavian Caledonides, Orogeny https://www.sciencedirect.com/science/article/pii/S0040195121003279 Bjarne S. G. Almqvist Daria Cyprych Sandra Piazolo article Aupart2021 Article 2021 10.1016/j.epsl.2021.117137 Earth and Planetary Science Letters 574 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85114125693&doi=10.1016%2fj.epsl.2021.117137&partnerID=40&md5=27829988feae3c539522f2330848ef2a Cited by: 15; All Open Access, Green Open Access, Hybrid Gold Open Access Claire Aupart Luiz Morales Marguerite Godard Bjørn Jamtveit article Guzmán-Hidalgo2021 Fifty-four 2D seismic profiles and 13 boreholes were used to describe pre-impact and post-impact deposits in the Yucatán Shelf. Previous work has identified a pre-impact basin in the northwest portion of the Chicxulub structure. The geometry of seismic reflectors associated with the Mesozoic Era shows that this pre-impact depression, here named Yucatán Trough, extends from the southern part of the Yucatán Peninsula to the northern face of the Campeche Escarpment. Stratigraphic data from boreholes of the Yucatán Platform suggest that the main sedimentary fills of the Yucatán Trough are a thin series of Upper Jurassic-Lower Cretaceous red beds, followed by the evaporite-dominated Lower Cretaceous and the carbonate-dominated Upper Cretaceous sedimentary successions. Mapping of the Cretaceous-Paleogene (K/Pg) deposits allowed us to observe the morphology of the Yucatán Shelf by the time of the Chicxulub impact event. The two-way seismic time K/Pg deposits map in conjunction with the free-air gravity anomaly map of the northern Yucatán Block reveals that, before the impact, the carbonate platform was divided into two blocks by a ~ 95–205 km wide and ~ 470-km long trough-shaped depression, probably a rift-basin with a north-south orientation, in which the central structure of Chicxulub impact crater is contained. The seismic reflectors overlying the top of the K/Pg deposits show that, during the Cenozoic Era, both the Yucatán Trough and impact basin were filled by progradational sequences which flattened the surface completely until the current block of the Yucatán Platform was configured. © 2021 Elsevier B.V. 2021 10.1016/j.margeo.2021.106594 Marine Geology 441 Posgrado en Ciencias de la Tierra, Instituto de Geología, Universidad Nacional Autónoma de México, Cd. Universitaria, Coyoacán, Ciudad de México, C. P. 04510, Mexico; Seminario Universitario sobre Investigación en Hidrocarburos and Instituto de Geología, Universidad Nacional Autónoma de México, Cd. Universitaria, Coyoacán, Ciudad de México, C. P. 04510, Mexico; Rosenstiel School of Marine and Atmospheric Science, University of Miami, Florida, 33149-1031, United States; Facultad de Ingeniería, Universidad Nacional Autónoma de México, Cd. Universitaria, Coyoacán, Ciudad de México, C. P. 04510, Mexico; Instituto de Geofísica, Universidad Nacional Autónoma de México, Cd. Universitaria, Coyoacán, Ciudad de México, C. P. 04510, Mexico https://www.scopus.com/inward/record.uri?eid=2-s2.0-85113350278&doi=10.1016%2fj.margeo.2021.106594&partnerID=40&md5=9e93bd277f736f7f90aaf77b6dbd9064 cited By 0 E. Guzmán-Hidalgo J.M. Grajales-Nishimura G.P. Eberli J.E. Aguayo-Camargo J. Urrutia-Fucugauchi L. Pérez-Cruz article Cockell2021 We report on the effect of the end-Cretaceous impact event on the present-day deep microbial biosphere at the impact site. IODP-ICDP Expedition 364 drilled into the peak ring of the Chicxulub crater, México, allowing us to investigate the microbial communities within this structure. Increased cell biomass was found in the impact suevite, which was deposited within the first few hours of the Cenozoic, demonstrating that the impact produced a new lithological horizon that caused a long-term improvement in deep subsurface colonization potential. In the biologically impoverished granitic rocks, we observed increased cell abundances at impact-induced geological interfaces, that can be attributed to the nutritionally diverse substrates and/or elevated fluid flow. 16S rRNA gene amplicon sequencing revealed taxonomically distinct microbial communities in each crater lithology. These observations show that the impact caused geological deformation that continues to shape the deep subsurface biosphere at Chicxulub in the present day. © Copyright © 2021 Cockell, Schaefer, Wuchter, Coolen, Grice, Schnieders, Morgan, Gulick, Wittmann, Lofi, Christeson, Kring, Whalen, Bralower, Osinski, Claeys, Kaskes, de Graaff, Déhais, Goderis, Hernandez Becerra, Nixon and IODP-ICDP Expedition 364 Scientists. 2021 10.3389/fmicb.2021.668240 Frontiers in Microbiology 12 UK Centre for Astrobiology, School of Physics and Astronomy, University of Edinburgh, Edinburgh, United Kingdom; WA-Organic and Isotope Geochemistry Centre (WA-OIGC), School of Earth and Planetary Sciences, The Institute for Geoscience Research, Curtin University, Bentley, WA, Australia; MARUM-Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany; Department of Earth Science and Engineering, Imperial College London, London, United Kingdom; Institute for Geophysics, Jackson School of Geosciences, University of Texas at Austin, Austin, TX, United States; Department of Geological Sciences, Jackson School of Geosciences, University of Texas at Austin, Austin, TX, United States; Center for Planetary Systems Habitability, University of Texas at Austin, Austin, TX, United States; Arizona State University, Eyring Materials Center, Tempe, AZ, United States; Géosciences Montpellier, Université de Montpellier, CNRS, Montpellier, France; Lunar and Planetary Institute, Houston, TX, United States; Department of Geosciences, University of Alaska Fairbanks, Fairbanks, AK, United States; Department of Geosciences, Pennsylvania State University, University Park, PA, United States; Institute for Earth and Space Exploration and Department of Earth Sciences, University of Western Ontario, London, ON, Canada; Environmental and Geo-Chemistry, Vrije Universiteit Brussel, Brussels, Belgium; Department of Earth and Environmental Sciences, University of Manchester, Manchester, IN, United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-85109762410&doi=10.3389%2ffmicb.2021.668240&partnerID=40&md5=ab7628f5005cc36ae73afb10c6612615 cited By 4 C.S. Cockell B. Schaefer C. Wuchter M.J.L. Coolen K. Grice L. Schnieders J.V. Morgan S.P.S. Gulick A. Wittmann J. Lofi G.L. Christeson D.A. Kring M.T. Whalen T.J. Bralower G.R. Osinski P. Claeys P. Kaskes S.J. Graaff T. Déhais S. Goderis N. Hernandez Becerra S. Nixon IODP-ICDP Expedition 364 Scientists article Zhao2021755 Large impact structures with peak rings are common landforms across the solar system, and their formation has implications for both the interior structure and thermal evolution of planetary bodies. Numerical modeling and structural studies have been used to simulate and ground truth peak-ring formative mechanisms, but the shock metamorphic record of minerals within these structures remains to be ascertained. We investigated impact-related microstructures and high-pressure phases in zircon from melt-bearing breccias, impact melt rock, and granitoid basement from the Chicxulub peak ring (Yucatán Peninsula, Mexico), sampled by the International Ocean Discovery Program (IODP)/International Continental Drilling Project (IODP-ICDP) Expedition 364 Hole M0077A. Zircon grains exhibit shock features such as reidite, zircon twins, and granular zircon including “former reidite in granular neoblastic” (FRIGN) zircon. These features record an initial high-pressure shock wave (>30 GPa), subsequent relaxation during the passage of the rarefaction wave, and a final heating and annealing stage. Our observed grain-scale deformation history agrees well with the stress fields predicted by the dynamic collapse model, as the central uplift collapsed downward-then-outward to form the peak ring. The occurrence of reidite in a large impact basin on Earth represents the first such discovery, preserved due to its separation from impact melt and rapid cooling by the resurging ocean. The coexistence of reidite and FRIGN zircon within the impact melt–bearing breccias indicates that cooling by seawater was heterogeneous. Our results provide valuablen information on when different shock microstructures form and how they are modified according to their position in the impact structure, and this study further improves on the use of shock barometry as a diagnostic tool in understanding the cratering process. © 2021 Geological Society of America. For permission to copy, contact editing@geosociety.org. 2021 10.1130/G48278.1 Geology 49 755-760 State Key Laboratory of Geological Processes and Mineral Resources, Planetary Science Institute, School of Earth Sciences, China University of Geosciences, Wuhan, 430074, China; Chinese Academy of Sciences Center for Excellence in Comparative Planetology, Hefei, 230026, China; Planetary Environmental and Astrobiological Research Laboratory, School of Atmospheric Sciences, Sun Yat-sen University, Zhuhai, 519082, China; Department of Earth Science and Engineering, Imperial College London, London, SW7 2BP, United Kingdom; Department of Earth Sciences, University of Western Ontario, London, ON N6A 5B7, Canada; Institute for Earth and Space Exploration, University of Western Ontario, London, ON N6A 5B7, Canada; Department of Civil Engineering and Geological Sciences, University of Notre Dame, Notre Dame, Indiana 46556, United States; Institute for Geophysics & Department of Geological Sciences, Jackson School of Geosciences, University of Texas at Austin, Austin, Texas 78758-4445, United States; Center for Planetary Systems Habitability, University of Texas at Austin, Austin, Texas 78758-4445, United States; Institut für Geologie, Universität Hamburg, Hamburg, 20146, Germany; Analytical, Environmental and Geo-Chemistry, Vrije Universiteit Brussel, Pleinlaan 2, Brussels, 1050, Belgium; Centre for Earth Evolution and Dynamics, University of Oslo, Oslo, NO-0315, Norway; Department of Applied Geology, The Institute for Geoscience Research, Curtin University, GPO Box U1987, Perth, WA 6845, Australia; State Key Laboratory of Lunar and Planetary Sciences, Macau University of Science and Technology, Macau, China 7 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85109462138&doi=10.1130%2fG48278.1&partnerID=40&md5=9d9c6422882283b5b86ceac0e685d77c cited By 5 J. Zhao L. Xiao Z. Xiao J.V. Morgan G.R. Osinski C.R. Neal S.P.S. Gulick U. Riller P. Claeys S. Zhao N.C. Prieur A. Nemchin S. Yu article Gao2021 From the latest Cretaceous (late Campanian to Maastrichtian, ~75–66 Ma) to the earliest Paleogene, fluctuations in greenhouse climate, inferred primarily from marine sediments, have been linked to volcanism, the Chicxulub asteroid impact, and the Cretaceous-Paleogene (K-Pg) mass extinction. In this paper, we summarize terrestrial climate records in mid-latitude East Asia during the latest Cretaceous and across the K-Pg boundary, based on a multi-proxy approach from the geochronologically well-constrained Sifangtai and Mingshui formations (SMF), accessed by scientific drilling of the Songliao Basin in northeastern China. Evolution of sedimentary environments is characterized by five depositional units of fluvial-deltaic-lacustrine facies. Development of four types of paleosols, including Inceptisols, Aridisols, Vertisols and Alfisols, is interpreted to primarily reflect climatic changes. Correlations among sedimentary facies, paleosol features, illite chemistry index, chemical index of alteration, as well as stable and clumped isotopes of pedogenic carbonates and clay minerals of the SMF validate their reliability for paleoclimate reconstruction, and indicate significant fluctuations in terrestrial climate and sedimentary environment. During global warming intervals possibly triggered by volcanism (e.g. ~69.5–68.5 Ma), the Songliao Basin experienced a warmer and wetter climate with stronger terrestrial chemical weathering and more monsoon-derived moisture sourced from the Pacific. In contrast, during global cooling intervals (e.g. ~70.5–69.5 Ma and ~ 68.5–66.5 Ma), the SMF record a cooler and drier climate with less intensive chemical weathering and more westerlies-derived moisture. Across the K-Pg boundary, dramatic changes in land temperatures and hydroclimate correspond to the latest Maastrichtian warming episode (~66.4–66.1 Ma), the transient cooling preceding the K-Pg boundary (~66.1–66.0 Ma), and the earliest Paleogene warming interval (~66.0–65.7 Ma). Temporal correlation of weathering index changes with the Deccan Traps volcanism suggests that volcanism and subsequent intensified weathering played a major role for climatic changes across the K-Pg boundary. The integrated records of sedimentological and geochemical datasets from the Songliao Basin robustly demonstrate that the terrestrial climate of mid-latitude East Asia responded strongly to greenhouse climate changes and to the catastrophic geological events from the latest Cretaceous to the earliest Paleogene. © 2021 Elsevier B.V. 2021 English 00128252 10.1016/j.earscirev.2021.103572 Earth-Science Reviews 216 Elsevier B.V. State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences (Beijing), Beijing, 100083, China; School of Earth Sciences and Resources, China University of Geosciences (Beijing), Beijing, 100083, China; Department of Geological Sciences, Stanford University, Stanford, CA 94305, United States; Department of Earth and Planetary Science, University of California, Berkeley, CA 94720, United States; Institute at Brown for Environment and Society and the Department of Earth, Environmental and Planetary Science, Brown University, Providence, RI 02912, United States; Max Planck Institute for Meteorology, Hamburg, 20146, Germany; Senckenberg Biodiversity and Climate Research Center, Frankfurt, 60325, Germany; Key Lab for the Evolution of Past Life and Environment in Northeast Asia, Ministry of Education, Jilin University, Changchun, 130026, China; School of Ocean Sciences, China University of Geosciences (Beijing), Beijing, 100083, China; Department of Geoscience, University of Wisconsin–Madison, Madison, WI 53706, United States Cretaceous; depositional environment; fluvial deposit; lacustrine deposit; midlatitude environment; Paleogene; proxy climate record; terrestrial environment, China; Songliao Basin, Asteroidea https://www.scopus.com/inward/record.uri?eid=2-s2.0-85104955210&doi=10.1016%2fj.earscirev.2021.103572&partnerID=40&md5=9b13123051cefb05cc90af6198cf40b1 cited By 16 Y. Gao D.E. Ibarra J.K. Caves Rugenstein J. Chen T. Kukla K. Methner H. Huang Z. Lin L. Zhang D. Xi H. Wu A.R. Carroll S.A. Graham C.P. Chamberlain C. Wang article Simpson2021 Article 2021 10.1029/2021GL093862 Geophysical Research Letters 48 14 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85111474139&doi=10.1029%2f2021GL093862&partnerID=40&md5=e874533b369e1619f8b0210fe5838df7 Cited by: 8 Jonathan Simpson Kasper Wijk Ludmila Adam article Li2021261 In this article, we review our previous research for spatial and temporal characterizations of the San Andreas Fault (SAF) at Parkfield, using the fault-zone trapped wave (FZTW) since the middle 1980s. Parkfield, California has been taken as a scientific seismic experimental site in the USA since the 1970s, and the SAF is the target fault to investigate earthquake physics and forecasting. More than ten types of field experiments (including seismic, geophysical, geochemical, geodetic and so on) have been carried out at this experimental site since then. In the fall of 2003, a pair of scientific wells were drilled at the San Andreas Fault Observatory at Depth (SAFOD) site; the main-hole (MH) passed a ~200-m-wide low-velocity zone (LVZ) with highly fractured rocks of the SAF at a depth of ~3.2 km below the wellhead on the ground level (Hickman et al., 2005; Zoback, 2007; Lockner et al., 2011). Borehole seismographs were installed in the SAFOD MH in 2004, which were located within the LVZ of the fault at ~3-km depth to probe the internal structure and physical properties of the SAF. On September 28 2004, a M6 earthquake occurred ~15 km southeast of the town of Parkfield. The data recorded in the field experiments before and after the 2004 M6 earthquake provided a unique opportunity to monitor the co-mainshock damage and post-seismic heal of the SAF associated with this strong earthquake. This retrospective review of the results from a sequence of our previous experiments at the Parkfield SAF, California, will be valuable for other researchers who are carrying out seismic experiments at the active faults to develop the community seismic wave velocity models, the fault models and the earthquake forecasting models in global seismogenic regions. © The Seismological Society of China and Institute of Geophysics, China Earthquake Administration 2021. 2021 English 16744519 10.29382/eqs-2021-0014 Earthquake Science 34 Earthquake Science 261-285 Department of Earth Sciences, University of Southern California, Los Angeles, 90089, United States 3 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85117065096&doi=10.29382%2feqs-2021-0014&partnerID=40&md5=f07d4bb6af51e95768e69f70d41816ce cited By 2 Y.-G. Li article kotowski2021structural 2021 Journal of Geophysical Research: Solid Earth 126 Wiley Online Library e2021JB021702 12 Alissa J Kotowski Mark Cloos Daniel F Stockli Eytan Bos Orent article Gupta20211556 Anthropogenic seismicity has been observed due to filling of artificial water reservoirs, geothermal and natural oil/gas production, and gold/coal mining under favorable geological conditions. Among these, artificial water reservoir triggered seismicity (RTS) is most prominent, with over 200 sites globally where RTS has been observed, including 5 sites where earthquakes exceeding M 6 magnitude occurred. Koyna, located near the west coast of India in stable Deccan Volcanic Province is the most prominent site where the largest RTS event of M 6.3 occurred in 1967, and the RTS has continued till now, for near field study of earthquakes. Here we present a summary of (a) global RTS, (b) scientific work carried in the Koyna region, (c) characterizing RTS, and (d) establishing a 3 km deep Pilot Borehole laboratory as a precursor to setting up of a ∼ 7 km deep bore hole laboratory. The work being carried out is providing necessary inputs for the design of the ∼ 7 km deep borehole laboratory for the near field studies of RTS and shed light on the geneses of earthquakes in general and RTS. © 2021, GEOL. SOC. INDIA. 2021 English 00167622 10.1007/s12594-021-1913-x Journal of the Geological Society of India 97 Springer 1556-1564 CSIR-National Geophysical Research Institute, Hyderabad, 500 007, India 12 earthquake magnitude; earthquake trigger; geothermal energy; geothermal power; hydrocarbon reservoir; seismicity, India; Koyna; Maharashtra https://www.scopus.com/inward/record.uri?eid=2-s2.0-85121464911&doi=10.1007%2fs12594-021-1913-x&partnerID=40&md5=f539c7dd344fb2826c34a5dcd310e6f0 cited By 0 H.K. Gupta article Stockhecke2021 Article 2021 10.1016/j.palaeo.2021.110535 Palaeogeography, Palaeoclimatology, Palaeoecology 577 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85109014988&doi=10.1016%2fj.palaeo.2021.110535&partnerID=40&md5=bf804fb544f148d02a666ad59bfb3ded Cited by: 11; All Open Access, Green Open Access, Hybrid Gold Open Access Mona Stockhecke Achim Bechtel Francien Peterse Typhaine Guillemot Carsten J. Schubert article deOliveira2021297 Early Archean spherule layers, widely accepted to represent distal ejecta deposits from large-scale impact events onto the early Earth, have been described from several stratigraphic levels of the Barberton greenstone belt in South Africa. Recently, exploration drilling at the Fairview Gold Mine (25°43'53'S, 31°5'59'E) in the northern domain of the belt resulted in the discovery of a new set of spherule layer intersections. The Fairview spherule layers in drill cores BH5901, BH5907, BH5911, and BH5949 were intersected just a few meters apart, at about the same stratigraphic position within the transition from the Onverwacht Group to the Fig Tree Group. The Fairview spherule layers have petrographic and chemical similarities to at least three other well-known Barberton spherule layers (S2-S4), and multiple spherule layer bed intersections in drill cores BARB5 and CT3, all from about the same stratigraphic position. They are not uniform in composition, in particular with respect to abundances of highly siderophile elements. The highest concentrations of moderately (Cr, Co, Ni) and highly siderophile (Ir) elements are within the range of concentrations for chondrites and, thus, reinforce the impact hypothesis for the generation of the Fairview spherule layers. Iridium peak concentrations and Cr/Ir interelement ratios for spherule layer samples from drill cores BH5907, BH5911, and BH5949 suggest admixtures of 50%-60% chondritic material, whereas for the BH5901 spherule layer, only an admixture of 1% chondritic material is indicated. We discuss whether these four Fairview spherule layers represent the same impact event, and whether they can be correlated to any of the S2-S4, CT3, and BARB5 intersections. © 2021 The Geological Society of America. Article 2021 English 00721077 10.1130/2021.2550(12) Special Paper of the Geological Society of America 550 Geological Society of America 297 – 331 Barberton Greenstone Belt; Core drilling; Economic geology; Gold deposits; Gold mines; Infill drilling; Stratigraphy; Admixture; Archaean; Barberton; Chemical component; Drill core; Greenstone belts; Impact events; Impact spherules; Large-scale impacts; South Africa; Archean; chemical composition; chondrite; concentration (composition); drilling; iridium; mine; petrography; spherule; Drills https://www.scopus.com/inward/record.uri?eid=2-s2.0-85126281105&doi=10.1130%2f2021.2550%2812%29&partnerID=40&md5=91b76e9eb0eab1983c9df039c8ef67e7 Cited by: 0 Grace Juliana Gonçalves Oliveira Wolf Uwe Reimold Alvaro Penteado Crósta Natalia Hauser Christian Koeberl Dieter Mader Ralf-Thomas Schmitt Tanja Mohr-Westheide article okazaki2021major We quantified mineral proportions in listvenite (completely carbonated peridotite) in Hole BT1B drilled across the basal thrust of the Samail ophiolite by the International Continental Scientific Drilling Project Oman Drilling Project using 3D X-ray Computed Tomography (XCT). We analyzed &gt;250,000 XCT images from a continuous ∼200 m listvenite core. Histograms of the intensity of X-ray attenuation of each XCT core-slice image were fitted assuming that the listvenites are composed of magnesite, quartz, and dolomite. The XCT mineral peaks were confirmed by comparison with chemical mapping data obtained using an X-ray fluorescence (XRF) core scanner. Listvenite matrix is composed almost entirely of magnesite and quartz, consistent with discrete XRD and XRF data. Veins are composed mostly of dolomite. The mean abundance of dolomite in listvenite from BT1B is 11 vol.%, whereas that in core sections within 15 m of the basal thrust is &gt;50 vol.%, suggesting the basal thrust acted as a source of Ca- and CO2-rich fluids. The SiO2:MgO:CaO molar ratio in the entire core from BT1B is 42:52:6, similar to that of onboard XRF data for discrete samples (41:54:5), whereas average Oman peridotites have ratios of (39:60:1), indicating Ca addition perhaps during carbonation. P- and S-wave velocities and density of listvenite are close to those of peridotite and are higher than those of serpentinites. These results suggest that limited material transfer during carbonation and hydration of the Samail ophiolite, except for Ca, CO2, and H2O. Listvenites formed in the mantle wedge above subduction zones may be an overlooked reservoir for carbon in the Earth's interior. © 2021. American Geophysical Union. All Rights Reserved. 2021 English 21699313 10.1029/2021JB022719 Journal of Geophysical Research: Solid Earth 126 Wiley Online Library e2021JB022719 Kochi Institute for Core Sample Research, X-star, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Kochi, Japan; Department of Earth and Planetary Sciences, Graduate School of Environmental Studies, Nagoya University, Nagoya, Japan; Research Institute for Marine Geodynamics, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokosuka, Japan; Department of Education, Meisei University, Tokyo, Japan; Department of Earth and Planetary Systems Science, Hiroshima University, Hiroshima, Japan; Mantle Drilling Promotion Office, MarE3, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokosuka, Japan; Division of Natural System, Graduate School of Natural Science & Technology, Kanazawa University, Kanazawa, Japan; Department of Geology and Geophysics, University of Hawai'i at Mānoa, Honolulu, HI, United States; Marine Geology and Geophysics Division of Ocean Sciences, National Science Foundation, Alexandria, VA, United States; Lamont Doherty Earth Observatory, Columbia University, New York, NY, United States 12 carbon storage; mantle structure; mineral; ophiolite; peridotite; physical property; tectonic plate; X-ray tomography https://www.scopus.com/inward/record.uri?eid=2-s2.0-85129487914&doi=10.1029%2f2021JB022719&partnerID=40&md5=f037e3d0fc5d65cfe4cf064dcdc79add cited By 4 Keishi Okazaki Katsuyoshi Michibayashi Kohei Hatakeyama Natsue Abe Kevin TM Johnson Peter B Kelemen Oman Drilling Project Science Team article Sier2021 The principal objective of the Hominin Sites and Paleolakes Drilling project (HSPDP) is to study the relationship between climate and environmental change and the implications on human evolution in eastern Africa. For this purpose, HSPDP has recovered a 228 m core in the Chemeron Formation of the Baringo Basin (Kenya). The Chemeron Formation spans approximately 3.7 Myr, from around 1.6 to 5.3 Ma, and has yielded many vertebrate fossils, including fossil hominins. The magnetostratigraphy of the Baringo core contributes to the chronological framework. A total of 567 individual paleomagnetic samples were collected from 543 levels at regular intervals throughout the core and 264 were processed using thermal and alternative field stepwise demagnetizations. In most samples, distinct Low-Temperature (LT; 20–150 °C) and High-Temperature (HT; 150–550 °C) Characteristic Remanent Magnetization (ChRM) could be determined. Typical demagnetization behaviors and some rock magnetic experiments suggest titanomagnetite acts as the main carrier of the HT ChRM with pervasive secondary overprints in normal polarity expressed by the LT component. Normal and reversed polarities were identified based on the secondary overprints LT ChRM directions, either parallel or antiparallel to the HT ChRM directions respectively. Our study identified four paleomagnetic reversals interpreted as the Matuyama-Gauss, Gauss-Kaena, Kaena-Gauss and the Gauss-Mammoth transitions. These boundaries provide chronostratigraphic tie-points that can be combined with those derived from 40Ar/39Ar dating of tuffs (Deino et al., 2020) and together indicate that the HSPDP Baringo core has an age range of ~3.3 Ma to ~2.6 Ma. The consistent paleomagnetic and radioisotopic age constraints are incorporated into a Bayesian age model of the core (Deino et al., 2020). © 2021 Elsevier B.V. Article 2021 English 00310182 10.1016/j.palaeo.2020.110190 Palaeogeography, Palaeoclimatology, Palaeoecology 570 Elsevier B.V. Baringo; Kenya; Tugen Hills; Vertebrata; chronostratigraphy; demagnetization; environmental change; fossil record; hominid; human evolution; magnetostratigraphy; paleohydrology; paleomagnetism; titanomagnetite https://www.scopus.com/inward/record.uri?eid=2-s2.0-85100681118&doi=10.1016%2fj.palaeo.2020.110190&partnerID=40&md5=70a9b2bee97812d45ba3aefdd05e49bf Cited by: 1; All Open Access, Green Open Access Mark J. Sier Guillaume Dupont-Nivet Cor Langereis Alan L. Deino John D. Kingston Andrew S. Cohen article ellison2021low 2021 Journal of Geophysical Research: Solid Earth 126 Wiley Online Library e2021JB021981 6 Eric T Ellison Alexis S Templeton Spencer D Zeigler Lisa E Mayhew Peter B Kelemen Juerg M Matter Oman Drilling Project Science Party article Niu2021 The Songliao Basin (SLB) is a large terrestrial petroliferous basin located in northeastern China. The Nenjiang Formation represents excellent hydrocarbon source rocks for the Daqing oil field. Previous studies have indicated that the oil shale intervals from the first (K2n1 ) and second (K2n2 ) members of the Nenjiang Formation were formed in different depositional settings. In this study, we provide a new high-resolution (1 m interval) record from SK-1s core and compile three sets of published datasets from two drilling holes (Zk3389 and LY-1) and a composite outcrop section. According to the total organic carbon (TOC) chemostratigraphy, we have divided three variation cycles spanning from K2n1 to K2n2 and detected three potential oil shale intervals in the Nenjiang Formation. Combined with the productivity, salinity, and oxygenation proxies, we discuss the paleolimnological environmental changes during deposition of the Nenjiang Formation. Our new and compiled records support the model that excellent preservation conditions were associated with the formation of organic-rich sediments in the K2n1, while the productivity was the major controlling factor for organic matter enrichment in the K2n2 . © 2021 by the authors. Licensee MDPI, Basel, Switzerland. 2021 English 19961073 10.3390/en14164783 Energies 14 MDPI AG State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences (Beijing), Beijing, 100083, China; School of Earth Science and Resources, China University of Geosciences (Beijing), Beijing, 100083, China; Laboratory for Marine Geology, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, 266237, China 16 Deposition; Oil fields; Oil shale; Productivity, Depositional setting; Environmental change; Hydrocarbon source rocks; Organic carbon burial; Organic-rich sediment; Petroliferous basins; Preservation condition; Total Organic Carbon, Organic carbon https://www.scopus.com/inward/record.uri?eid=2-s2.0-85112325238&doi=10.3390%2fen14164783&partnerID=40&md5=8c93cc98d9f8996d1ec477a07644e5e8 cited By 1 L. Niu Y. Gao H. Huang X. Tian T. Dong Q. Yang X. Cao C. Wang article Feignon20211243 The IODP-ICDP Expedition 364 drilling recovered a 829 m core from Hole M0077A, sampling ~600 m of near continuous crystalline basement within the peak ring of the Chicxulub impact structure. The bulk of the basement consists of pervasively deformed, fractured, and shocked granite. Detailed geochemical investigations of 41 granitoid samples, that is, major and trace element contents, and Sr-Nd isotopic ratios are presented here, providing a broad overview of the composition of the granitic crystalline basement. Mainly granite but also granite clasts (in impact melt rock), granite breccias, and aplite were analyzed, yielding relatively homogeneous compositions between all samples. The granite is part of the high-K, calc-alkaline metaluminous series. Additionally, they are characterized by high Sr/Y and (La/Yb)N ratios, and low Y and Yb contents, which are typical for adakitic rocks. However, other criteria (such as Al2O3 and MgO contents, Mg#, K2O/Na2O ratio, Ni concentrations, etc.) do not match the adakite definition. Rubidium–Sr errorchron and initial 87Sr/86Srt=326Ma suggest that a hydrothermal fluid metasomatic event occurred shortly after the granite formation, in addition to the postimpact alteration, which mainly affected samples crosscut by shear fractures or in contact with aplite, where the fluid circulation was enhanced, and would have preferentially affected fluid-mobile element concentrations. The initial (ɛNd)t=326Ma values range from −4.0 to 3.2 and indicate that a minor Grenville basement component may have been involved in the granite genesis. Our results are consistent with previous studies, further supporting that the cored granite unit intruded the Maya block during the Carboniferous, in an arc setting with crustal melting related to the closure of the Rheic Ocean associated with the assembly of Pangea. The granite was likely affected by two distinct hydrothermal alteration events, both influencing the granite chemistry: (1) a hydrothermal metasomatic event, possibly related to the first stages of Pangea breakup, which occurred approximately 50 Myr after the granite crystallization, and (2) the postimpact hydrothermal alteration linked to a long-lived hydrothermal system within the Chicxulub structure. Importantly, the granites sampled in Hole M0077A are unique in composition when compared to granite or gneiss clasts from other drill cores recovered from the Chicxulub impact structure. This marks them as valuable lithologies that provide new insights into the Yucatán basement. © 2021 The Authors. Meteoritics & Planetary Science published by Wiley Periodicals LLC on behalf of The Meteoritical Society (MET) 2021 10.1111/maps.13705 Meteoritics and Planetary Science 56 1243-1273 Department of Lithospheric Research, University of Vienna, Althanstrasse 14, Vienna, A-1090, Austria; Research Unit: Analytical, Environmental & Geo-Chemistry, Department of Chemistry, Vrije Universiteit Brussel, AMGC-WE-VUB, Pleinlaan 2, Brussels, 1050, Belgium; Laboratoire G-Time, Université Libre de Bruxelles, Av. F.D. Roosevelt 50, Brussels, 1050, Belgium; Natural History Museum, Burgring 7, Vienna, A-1010, Austria 7 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85111937863&doi=10.1111%2fmaps.13705&partnerID=40&md5=7b181a4562612d56d0a5dfaa9a5d409e cited By 3 J.-G. Feignon S.J. Graaff L. Ferrière P. Kaskes T. Déhais S. Goderis P. Claeys C. Koeberl article Deino2021 The Baringo-Tugen Hills-Barsemoi 2013 drillcore (BTB13), acquired as part of the Hominin Sites and Paleolakes Drilling Project, recovered 228 m of fluvio-lacustrine sedimentary rocks and tuffs spanning a ~3.29–2.56 Ma interval of the highly fossiliferous and hominin-bearing Chemeron Formation, Tugen Hills, Kenya. Here we present a Bayesian stratigraphic age model for the core employing chronostratigraphic control points derived from 40Ar/39Ar dating of tuffs from core and outcrop, 40Ar/39Ar age calibration of related outcrop diatomaceous units, and core magnetostratigraphy. The age model reveals three main intervals with distinct sediment accumulation rates: an early rapid phase from 3.2–2.9 Ma; a relatively slow phase from 2.9–2.7 Ma; and the highest rate of accumulation from 2.7–2.6 Ma. The intervals of rapid accumulation correspond to periods of high Earth orbital eccentricity, whereas the slow accumulation interval corresponds to low eccentricity at 2.9–2.7 Ma, suggesting that astronomically mediated climate processes may be responsible for the observed changes in sediment accumulation rate. Lacustrine transgression-regression events, as delineated using sequence stratigraphy, dominantly operate on precession scale, particularly within the high eccentricity periods. A set of erosively based fluvial conglomerates correspond to the 2.9–2.7 Ma interval, which could be related to either the depositional response to low eccentricity or to the development of unconformities due to local tectonic activity. Age calibration of core magnetic susceptibility and gamma density logs indicates a close temporal correspondence between a shift from high- to low-frequency signal variability at ~3 Ma, approximately coincident the end of the mid-Piacenzian Warm Period, and the beginning of the cooling of world climate leading to the initiation of Northern Hemispheric glaciation c. 2.7 Ma. BTB13 and the Baringo Basin records may thus provide evidence of a connection between high-latitude glaciation and equatorial terrestrial climate toward the end of the Pliocene. © 2019 Elsevier B.V. Article 2021 English 00310182 10.1016/j.palaeo.2019.109519 Palaeogeography, Palaeoclimatology, Palaeoecology 570 Elsevier B.V. Baringo; Kenya; Tugen Hills; Bayesian analysis; chronostratigraphy; dating method; eccentricity; magnetic susceptibility; magnetostratigraphy; modeling; outcrop; sedimentary rock; sequence stratigraphy https://www.scopus.com/inward/record.uri?eid=2-s2.0-85076833758&doi=10.1016%2fj.palaeo.2019.109519&partnerID=40&md5=55fe390e5e973bc19e2fe76bc6186652 Cited by: 8; All Open Access, Green Open Access Alan L. Deino Mark J. Sier Dominique I. Garello C. Brenhin Keller John D. Kingston Jennifer J. Scott Guillaume Dupont-Nivet Andrew S. Cohen article Gao2021 From the latest Cretaceous (late Campanian to Maastrichtian, ~76-66 Ma) through the earliest Paleogene, changes of greenhouse climate were linked to catastrophic geological events and massive biotic extinction and were primarily derived from marine records. Here we present a high-resolution, tightly age-constrained, clay mineralogical record from the Sifangtai and Mingshui formations of the terrestrial Songliao Basin, northeast China. Smectite and illite are the dominant clay species and are derived from the weathering of parent rocks and/or pedogenesis in paleosols. We use the percentage ratio of smectite and illite, the illite chemistry index, and the percentage ratio of phyllosilicate clay minerals and quartz in clay fractions for paleoclimatic reconstruction. Our results show that from the latest Cretaceous through the earliest Paleogene, values of all three clay mineralogical proxies in the Songliao Basin are generally higher during warming intervals than those during cooling intervals. This dataset suggests that warming caused strengthened moisture delivery from the Pacific, increasing precipitation and intensified chemical weathering, whereas cooling was accompanied by increasing dryness and physical weathering. Across the Cretaceous-Paleogene boundary, the warming likely related to Deccan volcanism, the transient cooling afterwards, and the warming in the earliest Paleogene are characterized by changes in the illite chemistry index and paleosol carbonate stable isotopic excursions as shown in previously published records, reflecting fluctuations in hydroclimate and weathering intensity. Our work demonstrates that terrestrial climate and weathering intensity in the mid-latitude Songliao Basin fluctuated during the latest Cretaceous through the earliest Paleogene and sensitively responded to global climate changes. © 2021 Elsevier Ltd 2021 English 01956671 10.1016/j.cretres.2021.104827 Cretaceous Research 124 Academic Press State Key Laboratory of Biogeology and Environmental Geology, School of Earth Sciences and Resources, China University of Geosciences (Beijing), Beijing, 100083, China; Key Lab for the Evolution of Past Life and Environment in Northeast Asia, Ministry of Education, Jilin University, Changchun, 130026, China; Department of Earth and Planetary Science, University of California, Berkeley, CA 94720, United States; Institute at Brown for Environment and Society and the Department of Earth, Environmental and Planetary Science, Brown University, Providence, RI 02912, United States; Department of Earth and Environmental Science, University of Michigan, Ann Arbor, MI 48109, United States; State Key Laboratory of Marine Geology, Tongji University, Shanghai, 200092, China clay mineral; climate variation; Cretaceous-Paleogene boundary; midlatitude environment; paleoclimate; terrestrial environment; weathering, China; Songliao Basin https://www.scopus.com/inward/record.uri?eid=2-s2.0-85104066955&doi=10.1016%2fj.cretres.2021.104827&partnerID=40&md5=e70b7d109a9ec554b54bad5dd6b2ac4d cited By 6 Y. Gao D.E. Ibarra X. Du T. Dong Z. Liu C. Wang article Ebert2021479 During hypervelocity impacts, target rocks are subjected to shock wave compression with high pressures and differential stresses. These differential stresses cause microscopic shear-induced deformation, which can be observed in the form of kinking, twinning, fracturing, and shear faulting in a range of minerals. The orientation of these shear-induced deformation features can be used to constrain the maximum shortening axis. Under the assumption of pure shear deformation, the maximum shortening axis is parallel to the maximum principal axis of stress, σ1, which gives the propagation direction of the shock wave that passed through a rock sample. In this study, shocked granitoids cored from the uppermost peak ring of the Chicxulub crater (International Ocean Discovery Program [IODP]/International Continental Drilling Project [ICDP] Expedition 364) were examined for structures formed by shearing. Orientations of kink planes in biotite and basal planar deformation features (PDFs) in quartz were measured with a U-stage and compared to a previous study of feather feature orientations in quartz from the same samples. In all three cases, the orientations of the shortening axis derived from these measurements were in good agreement with each other, indicating that the shear deformation features all formed in an environment with similar orientations of the maximum principal axis of stress. These structures formed by shearing are useful tools that can aid in understanding the deformational effects of the shock wave, as well as constraining shock wave propagation and postshock deformation during the cratering process. © 2021 The Geological Society of America. 2021 10.1130/2021.2550(21) Special Paper of the Geological Society of America 550 479-493 Institute of Earth and Environmental Sciences-Geology, Universität Freiburg, Albertstraße 23B, Freiburg, 79104, Germany; Center for Planetary Systems Habitability, Jackson School of Geosciences, Institute for Geophysics, Department of Geological Sciences, University of Texas at Austin, 10100 Burnet Road Building ROC, Austin, TX 78758, United States; Enthought Inc., Austin, TX 78701, United States; Géosciences Montpellier, Université de Montpellier, Centre National de la Recherche Scientifique, Université des Antilles, Place E. Bataillon, Montpellier cedex 5, 34095, France; Department of Earth Sciences, University of Cambridge, Cambridge, CB2 3EQ, United Kingdom https://www.scopus.com/inward/record.uri?eid=2-s2.0-85126303789&doi=10.1130%2f2021.2550%2821%29&partnerID=40&md5=d3797a32e28345969beb11584ad30f9e cited By 0 M. Ebert M.H. Poelchau T. Kenkmann S.P.S. Gulick J. Lofi N. McCall A.S.P. Rae article Xie2021217 Deep earth science is the basic of deep resource exploitation. One critical challenge is to ascertain the physical and mechanical behaviours of rocks from different depths under in situ geological conditions. Rock mechanical experiments and theoretical studies suitable for shallow resource mining are difficult to consider the effects of deep in situ geological conditions of different buried depths on the rock physical and mechanical characteristics and engineering. This paper puts forward the concept and research content of"deep in situ rock mechanics". Using rock cores collected from 10 different depths(1 000 m to 6 400 m) of Songke second well, the different characteristics of rock mechanical behaviors at different buried depths are studied. An in situ stress restoration and reconstruction method is proposed to approximately simulate the influence of in situ geostress on rock physical and mechanical parameters. Uniaxial compression tests indicate that rock mechanical parameters increase nonlinearly with increasing the buried depth and hence, cannot be treated as constants. Triaxial compression experimental results manifest that rock mechanical parameters vary more obviously with the buried depth due to the geostress, which is different from those under uniaxial compression. Rock mechanical tests retaining the in situ geological condition suggest that the rock mechanical parameters can present more obvious nonlinear behaviors with increasing the buried depth in the case of geostress restoration and reconstruction. The peak strength and Young's modulus in the in situ stress restoration and reconstruction tests, showing a logarithmic function relationship with the buried depth, are larger than the results in the triaxial compression tests. Also, the post peak strain softening behavior in the in situ stress restoration and reconstruction tests is more obvious than that in the triaxial compression tests. Especially, when the burial depth exceeds 4 800 m, the influences of in situ stress restoration and reconstruction on Poisson's ratio, strain hardening modulus and post peak are more remarkable. This research can provide support for exploring deep scientific laws and improving deep resource acquisition capabilities. © 2021, Science Press. All right reserved. Article 2021 Chinese 10006915 10.13722/j.cnki.jrme.2020.0317 Yanshilixue Yu Gongcheng Xuebao/Chinese Journal of Rock Mechanics and Engineering 40 Biodiversity Research Center, Academia Sinica 217 – 232 2 Compression testing; Elastic moduli; Geology; Restoration; Rock mechanics; Strain hardening; Stresses; Logarithmic functions; Mechanical characteristics; Restoration and reconstruction; Rock mechanical parameters; Strain-hardening modulus; Tri-axial compression tests; Uni-axial compression; Uni-axial compression tests; Rocks https://www.scopus.com/inward/record.uri?eid=2-s2.0-85101070741&doi=10.13722%2fj.cnki.jrme.2020.0317&partnerID=40&md5=d12215d68a2c0678f430e3ce9950a110 Cited by: 48 Heping Xie Cunbao Li Mingzhong Gao Ru Zhang Feng Gao Jianbo Zhu article zhou2021contamination 2021 Geology 49 Geological Society of America 1272--1276 11 Haoyang Zhou Robert B Trumbull Ilya V Veksler Ilya N Bindeman Johannes Glodny Felix ED Kaufmann Dieter Rammlmair article elger_core-log-seismic_2021 Continental collision causes deformation in the crust along shear zones. However, the physical and chemical conditions at which these zones operate and the deformation processes that enable up to hundreds of km of tectonic transport are still unclear because of the depth at which they occur and the challenges in imaging them. Ancient exhumed collision zones allow us to investigate these processes much better, for example at the COSC-1 borehole in the central Scandinavian Caledonides. This study combines data from the COSC-1 borehole with different seismic measurements to provide constraints on the spatial lithological and textural configuration of the Seve Nappe Complex. This is one of the few studies that shows that core-log-seismic integration in metamorphic rocks allows to identify the spatial distribution of major lithological units. Especially gamma ray logs in combination with density data are powerful tools to distinguish between mafic and felsic lithologies in log-core correlation. Our results indicate that reflections along the borehole are primarily caused by compositional rather than textural changes. Reflections in the Seve Nappe Complex are not as distinct as in greater depths but continuous and several of them can be linked to magmatic intrusions, which have been metamorphically overprinted. Their setting indicates that the Seve Nappe Complex consists of the remnants of a volcanic continental margin. Our results suggest that ductile-deformed middle crustal reflectivity is primarily a function of pre-orogenic lithological variations which has to be considered when deciphering mountain building processes. 2021 en 1525-2027 https://doi.org/10.1029/2020GC009376 Geochemistry, Geophysics, Geosystems 22 e2020GC009376 3 central Scandinavian Caledonides, core-log-seismic integration, COSC-1 https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2020GC009376 \_eprint: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2020GC009376 Judith Elger Christian Berndt Felix Kästner Simona Pierdominici Jochem Kück Bjarne S. G. Almqvist Christopher Juhlin Henning Lorenz article ternieten2021carbon A large part of the hydrated oceanic lithosphere consists of serpentinites exposed in ophiolites. Serpentinites constitute reactive chemical and thermal systems and potentially represent an effective sink for CO2. Understanding carbonation mechanisms within ophiolites are almost exclusively based on studies of outcrops, which can limit the interpretation of fossil hydrothermal systems. We present stable and radiogenic carbon isotope data that provide insights into the isotopic trends and fluid evolution of peridotite carbonation in ICDP Oman Drilling Project drill holes BA1B (400-m deep) and BA3A (300-m deep). Geochemical investigations of the carbonates in serpentinites indicate formation in the last 50 kyr, implying a distinctly different phase of alteration than the initial oceanic hydration and serpentinization of the Samail Ophiolite. The oldest carbonates (∼31 to &gt;50 kyr) are localized calcite, dolomite, and aragonite veins, formed between 26°C and 43°C and related to focused fluid flow. Subsequent pervasive small amounts of dispersed carbonate precipitated in the last 1,000 years. Macroscopic brecciation and veining of the peridotite indicate that carbonation is influenced by tectonic features allowing infiltration of fluids over extended periods and at different structural levels such as along fracture planes and micro-fractures and grain boundaries, causing large-scale hydration of the ophiolite. The formation of dispersed carbonate is related to percolating fluids with δ18O lower than modern ground and meteoric water. Our study shows that radiocarbon investigations are an essential tool to interpret the carbonation history and that stable oxygen and carbon isotopes alone can result in ambiguous interpretations. © 2021 The Authors. 2021 English 21699313 10.1029/2021JB022712 Journal of Geophysical Research: Solid Earth 126 Wiley Online Library e2021JB022712 Department of Earth Sciences, ETH Zurich, Zurich, Switzerland 12 carbon cycle; carbon sequestration; carbonate; drilling; hydrothermal system; radiocarbon dating; serpentinization; temperature anomaly, Oman https://www.scopus.com/inward/record.uri?eid=2-s2.0-85121720934&doi=10.1029%2f2021JB022712&partnerID=40&md5=725bab7f2eee23c048657803579e9a19 cited By 3 Lotta Ternieten Gretchen L Früh-Green Stefano M Bernasconi inproceedings jones2021coring 2021 EGU General Assembly Conference Abstracts EGU21--15570 Morgan Jones Ella Stokke Sverre Planke Lars Augland Henrik Svensen Christian Tegner Appy Sluijs Joost Frieling Tamsin Mather Ritske Huismans article lorenz_cosc-2_2021 2021 https://doi.org/10.5880/ICDP.5054.002 GFZ German Research Centre for Geosciences https://doi.org/10.5880/ICDP.5054.003 H. Lorenz C. Juhlin J.E. Rosberg M. Bazargan I. Klonowska R. Lescoutre S. Rejkjær G. Westmeijer G. Ziemniak article Wagner2021 Article 2021 10.1016/j.chemgeo.2021.120121 Chemical Geology 576 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85106326432&doi=10.1016%2fj.chemgeo.2021.120121&partnerID=40&md5=6bd2be8bd0df0dbc7afe8b63c88ad5f5 Cited by: 19 Luise J. Wagner Ilka C. Kleinhanns Nadja Weber Michael G. Babechuk Axel Hofmann Ronny Schoenberg article katayama2021crack To assess the geometry of cracks in highly altered peridotites, we analyzed the ultrasonic velocity of serpentinized dunites and harzburgites collected by the Oman Drilling Project (Holes BA1B, 3A, and 4A). First, we estimated the hydrated fraction from grain density to obtain the porosity-free matrix velocity, which indicated complete serpentinization at shallow depths and decreasing hydration at greater depths. We assume that the difference between the solid matrix and measured onboard ultrasonic velocity is attributed to cracks with a spheroidal shape in the samples. Application of the effective medium theory to onboard data, such as P-wave velocity and porosity, indicates that the average pore aspect ratio is mostly between 0.1 and 0.01, and crack density varies from 0.58 to 0.02. We found a positive relationship between aspect ratio and hydrated fraction, suggesting a change in crack shape related to dissolution–precipitation processes during hydration. The relatively high aspect ratio and hence high fluid flux at shallow depths are also consistent with the onboard resistivity data and present-day hydration processes inferred from the borehole fluid chemistry. The inversion of ultrasonic data provides a series of elastic moduli that can be used to make a rough approximation of Poisson's ratio from the onboard data, which is a key physical property for interpreting geophysical observations in the oceanic lithosphere. © 2021 The Authors 2021 English 00401951 10.1016/j.tecto.2021.228978 Tectonophysics 814 Elsevier 228978 Department of Earth and Planetary Systems Science, Hiroshima University, Hiroshima, 739-8526, Japan; Mantle Drilling Promotion Office, MarE3, JAMSTECKanagawa 236-0001, Japan; Kochi Institute for Core Sample Research, X-star, JAMSTEC, Kochi, 783-8502, Japan; Graduate School of Environmental Studies, Department of Earth and Planetary Sciences, Nagoya UniversityAichi 464-8602, Japan; Géosciences Montpellier, CNRS, Université de Montpellier, Montpellier, 34095, France; Lamont Doherty Earth Observatory, Columbia University, New York, 10964, United States Boreholes; Hydration; Infill drilling; Matrix algebra; Porosity; Seismic waves; Ultrasonic velocity; Wave propagation, Effective medium theories; Geophysical observations; High aspect ratio; Hydration process; Oceanic lithosphere; Precipitation process; Rough approximations; Serpentinized peridotites, Aspect ratio, cracking (fracture); dunite; fracture geometry; harzburgite; hydration; Poisson ratio; serpentinization; ultrasonics; wave velocity, Oman https://www.scopus.com/inward/record.uri?eid=2-s2.0-85114063954&doi=10.1016%2fj.tecto.2021.228978&partnerID=40&md5=9772e84d84f548f6de37dd72a63a13b9 cited By 1 Ikuo Katayama Natsue Abe Keishi Okazaki Kohei Hatakeyama Yuya Akamatsu Katsuyoshi Michibayashi Marguerite Godard Peter Kelemen The Oman Drilling Project Phase Science Party article kastner_cross-scale_2021 Metamorphic and deformed rocks in thrust zones show particularly high seismic anisotropy causing challenges for seismic imaging and interpretation. A good example is the Seve Nappe Complex in central Sweden, an old exhumed orogenic thrust zone that is characterized by a strong but incoherent seismic reflectivity and considerable seismic anisotropy. However, only little is known about their origin in relation to composition and structural influences on measurements at different seismic scales. Here, we present a new integrative study of cross-scale seismic anisotropy analyses combining mineralogical composition, microstructural analyses, and seismic laboratory experiments from the COSC-1 borehole, which sampled a 2.5-km-deep section of metamorphic rocks deformed in an orogenic root now preserved in the Lower Seve Nappe. While there is strong crystallographic preferred orientation in most samples in general, variations in anisotropy depend mostly on bulk mineral composition and dominant core lithology as shown by a strong correlation between these. This relationship enables to identify three distinct seismic anisotropy facies providing a continuous anisotropy profile along the borehole. Moreover, comparison of laboratory seismic measurements and electron-backscatter diffraction data reveals a strong scale dependence, which is more pronounced in the highly deformed, heterogeneous samples. This highlights the need for comprehensive cross-validation of microscale anisotropy analyses with additional lithological data when integrating seismic anisotropy over seismic scales. 2021 en 2169-9356 10.1029/2020JB021154 Journal of Geophysical Research: Solid Earth 126 e2020JB021154 5 COSC, core measurements, electron-backscatter diffraction, seismic anisotropy https://onlinelibrary.wiley.com/doi/abs/10.1029/2020JB021154 \_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2020JB021154 Felix Kästner Simona Pierdominici Alba Zappone Luiz F. G. Morales Franziska D. H. Wilke Christian Berndt article Neugebauer2021844 Due to a lack of visible tephras in the Dead Sea record, this unique palaeoenvironmental archive is largely unconnected to the well-established Mediterranean tephrostratigraphy. Here we present first results of the ongoing search for cryptotephras in the International Continental Drilling Program (ICDP) sediment core from the deep Dead Sea basin. This study focusses on the Lateglacial (~15–11.4 cal. ka BP), when Lake Lisan – the precursor of the Dead Sea – shrank from its glacial highstand to the Holocene low levels. We developed a glass shard separation protocol and counting procedure that is adapted to the extreme salinity and sediment recycling of the Dead Sea. Cryptotephra is abundant in the Dead Sea record (up to ~100 shards cm-3), but often glasses are physically and/or chemically altered. Six glass samples from five tephra horizons reveal a heterogeneous geochemical composition, with mainly rhyolitic and some trachytic glasses potentially sourced from Italian, Aegean and Anatolian volcanoes. Most shards likely originate from the eastern Anatolian volcanic province and can be correlated using major element analyses with tephra deposits from swarm eruptions of the Süphan Volcano ~13 ka BP and with ashes from Nemrut Volcano, presumably the Lake Van V-16 volcanic layer at ~13.8 ka BP. In addition to glasses that match the TM-10-1 from Lago Grande di Monticchio (15 820±790 cal. a BP) tentatively correlated with the St. Angelo Tuff of Ischia, we further identified a cryptotephra with glass analyses which are chemically identical with those of the PhT1 tephra in the Philippon peat record (13.9–10.5 ka BP), and also a compositional match for the glass analyses of the Santorini Cape Riva Tephra (Y-2 marine tephra, 22 024±642 cal. a BP). These first results demonstrate the great potential of cryptotephrochronology in the Dead Sea record for improving its chronology and connecting the Levantine region to the Mediterranean tephra framework. © 2021 The Authors. Boreas published by John Wiley & Sons Ltd on behalf of The Boreas Collegium. 2021 English 03009483 10.1111/bor.12516 Boreas 50 John Wiley and Sons Inc 844-861 Section Climate Dynamics and Landscape Evolution, GFZ German Research Centre for Geosciences, Telegrafenberg, Potsdam, 14473, Germany; Institute of Geosciences, University of Potsdam, Karl-Liebknecht-Str. 24–25, Potsdam, 14476, Germany; Department of Geography, Royal Holloway, University of London, Egham, TW20 0EX, United Kingdom; Department of Geography, University of Cambridge, Cambridge, CB2 3EN, United Kingdom; School of the Environment, Geography and Geosciences, University of Portsmouth, Portsmouth, PO1 3HE, United Kingdom; Section Chemistry and Physics of Earth Materials, GFZ German Research Centre for Geosciences, Telegrafenberg, Potsdam, 14473, Germany 3 geological record; Holocene; KTB borehole; late glacial; paleoenvironment; sediment core; tephra; tephrochronology, Dead Sea https://www.scopus.com/inward/record.uri?eid=2-s2.0-85101821823&doi=10.1111%2fbor.12516&partnerID=40&md5=38ce84aa56ff87a1629cf0f73ac85a5a cited By 3 I. Neugebauer D. Müller M.J. Schwab S. Blockley C.S. Lane S. Wulf O. Appelt A. Brauer article Duesing2021 Article 2021 10.1016/j.quascirev.2021.107219 Quaternary Science Reviews 273 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85118473788&doi=10.1016%2fj.quascirev.2021.107219&partnerID=40&md5=753dc298620a92e4f142f57f8f8d3c79 Cited by: 11 Walter Duesing Stefanie Kaboth-Bahr Asfawossen Asrat Andrew S. Cohen Verena Foerster Henry F. Lamb Frank Schaebitz Martin H. Trauth Finn Viehberg article bergsten2021basalt 2021 10.3389/fmicb.2021.728977 Frontiers in microbiology 12 Frontiers Media SA Pauline Bergsten Pauline Vannier Alexandra Maria Klonowski Stephen Knobloch Magnús Tumi Gudmundsson Marie Dolores Jackson Viggó Thór Marteinsson article Ulfers2021377 Lake Towuti is located on central Sulawesi/Indonesia, within the Indo Pacific Warm Pool, a globally important region for atmospheric heat and moisture budgets. In 2015 the Towuti Drilling Project recovered more than 1000 m of drill core from the lake, along with downhole geophysical logging data from two drilling sites. The cores constitute the longest continuous lacustrine sediment succession from the Indo Pacific Warm Pool. We combined lithological descriptions with borehole logging data and used multivariate statistics to better understand the cyclic sequence, paleoenvironments, and geochronology of these sediments. Accurate chronologies are crucial to analyze and interpret paleoclimate records. Astronomical tuning can help build age-depth models and fill gaps between age control points. Cyclostratigraphic investigations were conducted on a downhole magnetic susceptibility log from the lacustrine facies (10–98 m below lake floor) from a continuous record of sediments in Lake Towuti. This study provides insights into the sedimentary history of the basin between radiometric ages derived from dating a tephra layer (~ 797 ka) and C14-ages (~ 45 ka) in the cores. We derived an age model that spans from late marine isotope stage (MIS) 23 to late MIS 6 (903 ± 11 to 131 ± 67 ka). Although uncertainties caused by the relatively short record and the small differences in the physical properties of sediments limited the efficacy of our approach, we suggest that eccentricity cycles and/or global glacial-interglacial climate variability were the main drivers of local variations in hydroclimate in central Indonesia. We generated the first nearly complete age-depth model for the lacustrine facies of Lake Towuti and examined the potential of geophysical downhole logging for time estimation and lithological description. Future lake drilling projects will benefit from this approach, since logging data are available just after the drilling campaign, whereas core descriptions, though more resolved, only become available months to years later. © 2021, The Author(s). Article 2021 English 09212728 10.1007/s10933-020-00171-9 Journal of Paleolimnology 65 Springer Science and Business Media B.V. 377 – 392 4 Greater Sunda Islands; Lake Towuti; Malili Lakes; South Sulawesi; Sulawesi; Sunda Isles; borehole logging; cyclostratigraphy; eccentricity; facies analysis; lacustrine deposit; magnetic susceptibility; marine isotope stage; moisture content; paleoclimate; proxy climate record; tephra; warm pool https://www.scopus.com/inward/record.uri?eid=2-s2.0-85100995329&doi=10.1007%2fs10933-020-00171-9&partnerID=40&md5=5a081a525c5d24340e0c426e30322de6 Cited by: 3; All Open Access, Green Open Access, Hybrid Gold Open Access A. Ulfers K. Hesse C. Zeeden J.M. Russell H. Vogel S. Bijaksana T. Wonik article Takazawa2021507 The ICDP Oman Drilling Project carried out onshore drilling of the world's largest ophiolite, the Oman ophiolite (also known as Samail ophiolite). This drilling project provided an opportunity to explore major key boundaries of the oceanic lithosphere, represented by the Oman ophiolite, by drilling cores and boreholes. Below the layered gabbro at the bottom of the crustal section is the Moho Transition Zone(MTZ), which is mainly composed of dunite with small amounts of gabbroic sills. By drilling at the Wadi Zeeb CM site in the Wadi Tayin massif, cores were successfully collected from a 150 m MTZ. Also collected were fragile altered rocks from wadi outcrops that are easily lost. The core description campaign was carried out aboard deep-sea scientific drilling vessel “Chikyu” anchored at Shimizu Port. The core observations were performed and described according to the IODP procedure, and the analysis was conducted using many instruments. The resulting data provide important insights and will contribute to future drilling of the Mohorovicic discontinuity in the ocean. The most striking fact is that MTZ dunites are strongly influenced by serpentinization. In particular, the upper part of the MTZ just below the boundary with the lower crustal gabbro was most strongly altered, and a fracture zone was also developed. Understanding when and how these alterations occurred at the boundary between the crust and the mantle is an important future task. © 2021. All Rights Reserved. 2021 English 0022135X 10.5026/JGEOGRAPHY.130.507 Journal of Geography (Chigaku Zasshi) 130 Tokyo Geographical Society 507-525 Department of Geology, Faculty of Science, Niigata University, Niigata, 950-2181, Japan; Volcanoes and Earth's Interior Research Center, Research Institute for Marine Geodynamics, Japan Agency for Marine-Earth Science and Technology, Yokosuka, 237-0061, Japan 4 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85117418644&doi=10.5026%2fJGEOGRAPHY.130.507&partnerID=40&md5=d2aa6db1c9df9761f53e4d4c76a697d4 cited By 2 E. Takazawa article Muiruri2021 This study examines a one-million-year pollen record from a 194-m-long Lake Magadi core (HSPDP-MAG14-2A) in the south Kenya Rift Valley. The pollen indicate a general trend through the last 740 kyr from wetter conditions to generally drier environments. Grassland dominated with less common Podocarpus and Cyperaceae in a sparse flora between 1000 and 740 ka. Poaceae, woodland and herbaceous plants are common through the remaining core and abundant between 740 and 528 ka and after 200 ka. Pollen diversity increased after 200 ka. Podocarpus and Cyperaceae reached a peak abundance at ~575 ka with a subsequent decline that suggests a progressive increase in aridity, interrupted by wetter intervals. Podocarpus-dominated forests expanded and contracted many times during the Quaternary and document an anti-phased relationship with data from Lake Malawi. Similar anti-phased correlations are noted for herbaceous plants, suggesting that the two basins responded differently to the same climate or were influenced by contrasting climate regimes. Increases in macrocharcoal correlate with increasing pollen abundance and suggest wetter conditions. Data from the Magadi, Koora and Olorgesailie basins indicate similar trends and a dominant climate control on vegetation and habitats. Large lakes characterised all three basins at 740–528 ka with climate subsequently becoming drier, but with many wetter intervals. At various times the lakes expanded, contracted and dried out, except at Lake Magadi where spring inflows maintained lacustrine conditions through the late Quaternary. Faulting also contributed to fragmentation of the landscape and formation of a mosaic of habitats. An especially intense period of aridity at ~528–392 ka coincided with extinction of many large-bodied mammals and may have helped to drive a change from the use of Acheulean hand axes to the production of Middle Stone Age tools by 320 ka. After 200 ka pollen diversity increased substantially with a mix of montane, riparian and dry forest associations that were present in varying amounts through to ~4.2 ka at the core top. © 2021 Elsevier B.V. Article 2021 English 00310182 10.1016/j.palaeo.2021.110247 Palaeogeography, Palaeoclimatology, Palaeoecology 567 Elsevier B.V. East African Lakes; East African Rift; Kajiado; Kenya; Kenya Rift; Lake Magadi; Lake Malawi; Rift Valley; Cyperaceae; Mammalia; Poaceae; Podocarpus; Acheulean; dry forest; extinction; grassland; habitat fragmentation; habitat mosaic; historical record; mammal; Mesolithic; paleoenvironment; pollen; vegetation history https://www.scopus.com/inward/record.uri?eid=2-s2.0-85100722464&doi=10.1016%2fj.palaeo.2021.110247&partnerID=40&md5=e456cb4aab5178dd1b17d7c2047c7b71 Cited by: 7 Veronica M. Muiruri R. Bernhart Owen Tim K. Lowenstein Robin W. Renaut Robert Marchant Stephen M. Rucina Andrew Cohen Alan L. Deino Mark J. Sier Shangde Luo Kennie Leet Christopher Campisano Nathan M. Rabideaux Daniel Deocampo Chuan-Chou Shen Anthony Mbuthia Brant C. Davis Wadha Aldossari Chenyu Wang article Lu2021 The seismic origin of turbidites is verified either by correlating such layers to historic earthquakes, or by demonstrating their synchronous deposition in widely spaced, isolated depocenters. A historic correlation could thus constrain the seismic intensity required for triggering turbidites. However, historic calibration is not applicable to prehistoric turbidites. In addition, the synchronous deposition of turbidites is difficult to test if only one deep core is drilled in a depocenter. Here, we propose a new approach that involves analyzing the underlying in situ deformations of prehistoric turbidites, as recorded in a 457 m-long core from the Dead Sea center, to establish their seismic origin. These in situ deformations have been verified as seismites and could thus authenticate the trigger for each overlying turbidite. Moreover, our high-resolution chemical and sedimentological data validate a previous hypothesis that soft-sediment deformation in the Dead Sea formed at the sediment-water interface. © 2020. The Authors. 2021 English 00948276 10.1029/2020GL090947 Geophysical Research Letters 48 Blackwell Publishing Ltd Department of Geography, University of Liege, Liège, Belgium; Department of Geology, University of Innsbruck, Innsbruck, Austria; Dr. Moses Strauss Department of Marine Geosciences, University of Haifa, Haifa, Israel; Geological Survey of Israel, Jerusalem, Israel; The Neev Center for Geoinfomatics, Institute of Earth Sciences, Hebrew University of Jerusalem, Jerusalem, Israel; Department of Geophysics, Tel Aviv University, Tel Aviv, Israel; Department of Geology & Geophysics, University of Aberdeen, Scotland, United Kingdom 3 Deformation; Deposition, Dead sea basins; High resolution; Sediment water interface; Sedimentological data; Seismic intensity; Seismic origin; Situ deformation; Soft-sediment deformation, Earthquakes https://www.scopus.com/inward/record.uri?eid=2-s2.0-85100961710&doi=10.1029%2f2020GL090947&partnerID=40&md5=9213e6d48716e1fbe08566cb64319e47 cited By 14 Y. Lu J. Moernaut R. Bookman N. Waldmann N. Wetzler A. Agnon S. Marco G.I. Alsop M. Strasser A. Hubert-Ferrari article Yang2021 Fischer plots are widely used in paleoenvironmental research as graphic representations of sea- and lake-level changes through mapping linearly corrected variation of accumulative cycle thickness over cycle number or stratum depth. Some kinds of paleoenvironmental proxy data (especially subsurface data, such as natural gamma-ray logging data), which preserve continuous cyclic signals and have been largely collected, are potential materials for constructing Fischer Plots. However, it is laborious to count the cycles preserved in these proxy data manually and map Fischer plots with these cycles. In this paper, we introduce an original open-source Python code “PyFISCHERPLOT” for constructing Fischer Plots in batches utilizing paleoenvironmental proxy data series. The principle of constructing Fischer plots based on proxy data, the data processing and usage of the PyFISCHERPLOT code and the application cases of the code are presented. The code is compared with existing methods for constructing Fischer plots. © 2021, The Author(s). 2021 English 20452322 10.1038/s41598-021-90017-9 Scientific Reports 11 Nature Research State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing, 100083, China; School of the Earth Sciences and Resources, China University of Geosciences, Beijing, 100083, China; Exploration and Development Research Institute of Daqing Oil Field Corporation, Daqing, Heilongjiang 163712, China 1 article https://www.scopus.com/inward/record.uri?eid=2-s2.0-85105993065&doi=10.1038%2fs41598-021-90017-9&partnerID=40&md5=6a1b5c6027696871bab68cee92801d64 cited By 2 D. Yang Y. Huang Z. Chen Q. Huang Y. Ren C. Wang article ma2021review 2021 Earthquake Geology and Tectonophysics around Eastern Tibet and Taiwan Springer 63-82 Kuo-Fong Ma article Arp2021 Since its recognition as an impact structure 60 years ago, no volcanics were anticipated in the circular depression of the 14.8 Ma old Nördlinger Ries. Here, we describe for the first time a volcanic ash-derived clinoptilolite-heulandite-buddingtonite bed within the 330 m thick Miocene lacustrine crater fill. Zircon U-Pb ages of 14.20 ± 0.08 Ma point to the source of the volcanic ash in the Pannonian Basin, 760 km east of the Ries. The diagenetically derived zeolite-feldspar bed occurs in laminated claystones of the Ries soda-lake stage and represents the first unequivocal stratigraphic marker bed in this basin, traceable from marginal surface outcrops to 218 m below surface in the crater center. These relationships demonstrate a deeply bowl-shaped geometry of crater fill sediments, not explainable by sediment compaction and corresponding stratigraphic backstripping alone. Since most of the claystones formed at shallow water depths, the bowl-shaped geometry must reflect 134 +23/−49 m of sagging of the crater floor. We attribute the sagging to compaction and closure of the dilatant macro-porosity of the deeply fractured and brecciated crater floor during basin sedimentation and loading, a process that lasted for more than 0.6 Myr. As a result, the outcrop pattern of the lithostratigraphic crater-fill units in its present erosional plane forms a concentric pattern. Recognition of this volcanic ash stratigraphic marker in the Ries crater provides insights into the temporal and stratigraphic relationships of crater formation and subsidence that have implications for impact-hosted lakes on Earth and Mars. © 2021. The Authors. 2021 10.1029/2020JE006764 Journal of Geophysical Research: Planets 126 Geoscience Center, Georg-August-University, Göttingen, Germany; Geological Survey, Bavarian Environment Agency, Hof/Saale, Germany; MTA-ELTE Volcanology Research Group, Budapest, Hungary; Department of Earth, Environmental and Planetary Sciences, Brown University, Providence, RI, United States 4 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85104590683&doi=10.1029%2f2020JE006764&partnerID=40&md5=505e70dbb1e5e615f49eb400ff114452 cited By 4 G. Arp I. Dunkl D. Jung V. Karius R. Lukács L. Zeng A. Reimer III Head article templeton2021accessing 2021 Journal of Geophysical Research: Biogeosciences 126 Wiley Online Library e2021JG006315 10 Alexis S Templeton Eric T Ellison Clemens Glombitza Yuki Morono Kaitlin R Rempfert Tori M Hoehler Spencer D Zeigler Emily A Kraus John R Spear Daniel B Nothaft others article Zierenberg2021 Article 2021 10.1029/2021GC009747 Geochemistry, Geophysics, Geosystems 22 11 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85119882731&doi=10.1029%2f2021GC009747&partnerID=40&md5=81e828e42ded15d28f9ff8e0ba0f5b88 Cited by: 6; All Open Access, Hybrid Gold Open Access Robert A. Zierenberg Guðmundur Ó. Friðleifsson Wilfred A. Elders Peter Schiffman Andrew P. G. Fowler article Ormö2021 The rim wall of water formed from even a modestly-sized marine impact may be kilometers in height. Although modeling has shown that this wave swiftly breaks and relatively rapidly loses energy during outwards travel from the impact site, the portion of the rim wall that collapses inwards may generate a resurge flow with tremendous transport energy. Here we compare the deposits generated by this ocean resurge inside one of the largest marine-target craters on Earth, the 200-km wide Chicxulub crater, Yucatán Peninsula, México, with resurge deposits (breccias) in eight drill cores from five other marine-target craters in Sweden and the United States. Examination of the wide range of cored locations within the craters, and target water depths (H) relative to modeled projectile diameters (d) reveal a high correlation between location, average clast frequency (〈N〉), and d/H from which any of the four variables can be obtained. The relationship shown here may provide an important tool for diagnosing marine impact cratering processes where there is limited understanding of crater size and/or paleobathymetry. © 2021 The Authors 2021 10.1016/j.epsl.2021.116915 Earth and Planetary Science Letters 564 Centro de Astrobiologia (INTA-CSIC), Ctra Torrejon a Ajalvir km4, Torrejon de Ardoz, 28850, Spain; Inst. for Geophysics, Dept. of Geological Sciences, Jackson School of Geosciences, Univ. of Texas at Austin, 10100 Burnet Rd Bldg. ROC, Austin, TX 78758, United States; Center for Planetary Systems Habitability, Univ. of Texas at Austin, Austin, TX 78712, United States; Dept. of Geosciences, University of Alaska Fairbanks, United States; Dept. of Geosciences, Auburn University, 2058 Memorial Coliseum, Auburn, AL 36849, United States; Earth Sciences Centre, Univ. of Gothenburg, Sweden; Dept. of Earth Science and Engineering, Imperial College London, United Kingdom https://www.scopus.com/inward/record.uri?eid=2-s2.0-85104366669&doi=10.1016%2fj.epsl.2021.116915&partnerID=40&md5=394b9686c2db99a3b56fdbf5cf243b5a cited By 8 J. Ormö S.P.S. Gulick M.T. Whalen Jr. King E. Sturkell J. Morgan article Arnold2021 Article 2021 10.3389/feart.2021.606588 Frontiers in Earth Science 9 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85109213796&doi=10.3389%2ffeart.2021.606588&partnerID=40&md5=632b140220d5a1dad24df341d0b01413 Cited by: 8; All Open Access, Gold Open Access Gabriele E. Arnold Verena Foerster Martin H. Trauth Henry Lamb Frank Schaebitz Asfawossen Asrat Claudia Szczech Christina Günter inproceedings foubert2021afar 2021 EGU General Assembly Conference Abstracts EGU21--14486 Anneleen Foubert Tesfaye Kidane Derek Keir Balemwal Atnafu others article Wang202136 2021 English 00963941 10.1029/2021eo158455 Eos (United States) 102 American Geophysical Union 36-41 State Key Laboratory of Biogeology and Environmental Geology, School of Earth Sciences and Resources, China University of Geosciences, Beijing, China; Department of Geological Sciences, Stanford University, Stanford, CA, United States; Department of Earth and Planetary Science, University of California, Berkeley, United States; Institute at Brown for Environment and Society and the Department of Earth, Environmental and Planetary Science, Brown University, Providence, RI, United States; State Key Laboratory of Biogeology and Environmental Geology, School of Ocean Sciences, China University of Geosciences, Beijing, China; College of Earth Sciences, Jilin University, Changchun, China 7 climate variation; Cretaceous; future prospect; paleoclimate, China https://www.scopus.com/inward/record.uri?eid=2-s2.0-85116514842&doi=10.1029%2f2021eo158455&partnerID=40&md5=a04fa67265dcfaa7deb6944694754c27 cited By 8 C. Wang Y. Gao D.E. Ibarra H. Wu P. Wang article Qin2024168 Article 2021 10.12143/j.ztgc.2021.04.001 Drilling Engineering 48 1-10 04 J. Liang J. Zhao C. Wang X. He H. Yin article 2021 10.16452/j.cnki.sdkjzk.2021.05.001 Journal of Shandong University of Science and Technology (Natural Science) 40 1-9 T. Wang Y. Huang Z. Zhang C. Wang article nothaft2021aqueous 2021 Journal of Geophysical Research: Biogeosciences 126 Wiley Online Library e2021JG006319 9 Daniel B Nothaft Alexis S Templeton Eric S Boyd Juerg M Matter Martin Stute Amelia N Paukert Vankeuren Oman Drilling Project Science Team article Gupta20211415 Article 2021 Current Science 120 1415 – 1416 9 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85108144301&partnerID=40&md5=75db57dad07a42bc91b8d966971ea6fa Cited by: 3 Harsh K. Gupta article crotteau2021characterizing Although ocean crust covers over 60% of Earth's surface, the processes that form, cool, and alter the ocean crust are not completely understood. We utilize shortwave infrared micro-imaging spectroscopy of ∼1.2 km of rock cored by the International Continental Scientific Drilling Program's Oman Drilling Project to quantify hydration of basaltic dikes and gabbros from the Samail ophiolite as a function of depth, mineralogy and deformation. We develop a regression (R2 = 0.66) between area of the ∼1,350–1,650 nm OH/H2O absorption and measurements of loss on ignition of samples and apply this relationship to generate quantitative ∼250 μm/pixel hydration maps for all cores. The lowest mean hydration is observed in the most pervasively altered dike-gabbro boundary (GT3A, H2Omean = 2.1 ± 1.6 wt%), consistent with the low H2O content of the dominant alteration minerals, amphibole and epidote. The highest H2O content occurs in deeper foliated and layered gabbros (GT2A, H2Omean = 3.2 ± 3.0 wt%) and layered gabbros (GT1A, H2Omean = 2.8 ± 3.1 wt%). The greater prevalence with depth of zeolite alteration as opposed to lower wt% H2O amphibole at shallow stratigraphic depths, as well as the occurrence of zones of intensive hydration associated with fault zones (H2Omean = 5.7 ± 4.0 wt%) lead to greater hydration of the lower ocean crust. This new approach provides an objective quantification of hydration in these cores, enabling an improved understanding of quantities and characteristics of ocean crust hydration. It highlights the importance of specific phases and faulting in controlling hydration, which has implications for ocean crust cooling, rheological properties, and the role of alteration in global biogeochemical cycling. © 2021. The Authors. 2021 English 21699313 10.1029/2021JB022676 Journal of Geophysical Research: Solid Earth 126 Wiley Online Library e2021JB022676 Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, United States; Now at Department of Earth Science, University of California Santa Barbara, Santa Barbara, CA, United States; School of Geography, Earth and Environmental Sciences, Plymouth University, Plymouth, United Kingdom; Department of Earth & Environmental Sciences, Columbia University, Lamont–Doherty Earth Observatory, Palisades, NY, United States; School of Ocean and Earth Science, National Oceanography Centre Southampton, University of Southampton, Southampton, United Kingdom 11 dike; drilling; gabbro; hydration; infrared spectroscopy; oceanic crust; ophiolite; shortwave radiation https://www.scopus.com/inward/record.uri?eid=2-s2.0-85134022652&doi=10.1029%2f2021JB022676&partnerID=40&md5=de43cdd3706ac56462a336d287a33086 cited By 0 Molly A Crotteau Rebecca N Greenberger Bethany L Ehlmann George R Rossman Michelle Harris Peter B Kelemen Damon AH Teagle Oman Drilling Project Phase 1 Science Party article Cavosie2021201 High-pressure minerals provide records of processes not normally preserved in Earth's crust. Reidite, a quenchable polymorph of zircon, forms at pressures >20 GPa during shock compression. However, there is no broad consensus among empirical, experimental, and theoretical studies on the nature of the polymorphic transformation. Here we decipher a multistage history of reidite growth recorded in a zircon grain in distal impact ejecta (offshore northeastern United States) from the ca. 35 Ma Chesapeake Bay impact event which, remarkably, experienced near-complete conversion (89%) to reidite. The grain displays two distinctive reidite habits: (1) intersecting sets of planar lamellae that are dark in cathodoluminescence (CL); and (2) dendritic epitaxial overgrowths on the lamellae that are luminescent in CL. While the former is similar to that described in literature, the latter has not been previously reported. A two-stage growth model is proposed for reidite formation at >40 GPa in Chesapeake Bay impact ejecta: formation of lamellar reidite by shearing during shock compression, followed by dendrite growth, also at high pressure, via recrystallization. The dendritic reidite is interpreted to nucleate on lamellae and replace damaged zircon adjacent to lamellae, which may be amorphous ZrSiO4 or possibly an intermediate phase, all before quenching. These results provide new insights on the microstructural evolution of the high-pressure polymorphic transformation over the microseconds-long interval of reidite stability during meteorite impact. Given the formation conditions, dendritic reidite may be a unique indicator of distal ejecta. © 2020 Geological Society of America. 2021 English 00917613 10.1130/G47860.1 Geology 49 Geological Society of America 201-205 Space Science and Technology Centre, Institute for Geoscience Research, School of Earth and Planetary Science, Curtin University, Perth, Western Australia 6102, Australia; School of Earth and Space Exploration, Arizona State University, Tempe, Arizona 85287, United States; GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, 24148, Germany; U.S. Geological Survey, 926A National Center, Reston, Virginia 20192, United States; Department of Lithospheric Research, University of Vienna, Althanstrasse 14, Vienna, A-1090, Austria 2 Offshore drilling; Offshore oil well production; Semiconductor insulator boundaries; Silicate minerals; Structural geology; Zircon, Epitaxial overgrowth; Formation condition; Intermediate phase; Meteorite impact; Ocean drilling programs; Polymorphic transformation; Shock compressions; Theoretical study, Meteor impacts, ejecta; high pressure; microstructure; mineral resource; Ocean Drilling Program; zircon, Chesapeake Bay; United States, Indicator indicator https://www.scopus.com/inward/record.uri?eid=2-s2.0-85100380573&doi=10.1130%2fG47860.1&partnerID=40&md5=2ca2398ac6b5c496a76392cebc1bf9a0 cited By 4 A.J. Cavosie M.B. Biren K.V. Hodges J.-A. Wartho J.W. Horton Jr. C. Koeberl article Daskalopoulou2021 The Cheb Basin (Czech Republic) is characterized by emanations of magma-derived gases and repeated occurrences of mid-crustal earthquake swarms with small to intermediate magnitudes (ML < 4.5). Associated intense mantle degassing occurs at the Hartoušov Mofette, a representative site for the Cheb Basin. Here, we performed 14 sampling campaigns between June 2019 and March 2020. Gas samples of fluids ascending in two boreholes (F1, ∼28 m depth and F2, ∼108 m depth) and from a nearby natural mofette were analyzed for their chemical (CO2, N2, O2, Ar, He, CH4, and H2) and isotope compositions (noble gases and CO2). CO2 concentrations were above 99.1% in most samples, while O2 and N2 were below 0.6%. He ranged from 19 to 34 μmol/mol and CH4 was mostly below 12 μmol/mol. Isotope compositions of helium and carbon in CO2 ranged from 5.39 to 5.86 RA and from −2.4 to −1.3 ‰ versus VPDB, respectively. Solubility differences of the investigated gases resulted in fluctuations of their chemical compositions. These differences were accompanied by observed changes of gas fluxes in the field and at the monitoring station for F1. Variations in solubilities and fluxes also impacted the chemical concentration of the gases and the δ13C values that were also likely influenced by Fischer-Tropsch type reactions. The combination of (a) the Bernard ratio, (b) CH4/3He distributions, (c) P-T conditions, (d) heat flow, and (e) the sedimentary regime led to the hypothesis that CH4 may be of mixed biogenic and volcanic/geothermal origin with a noticeable atmospheric contribution. The drilling of a third borehole (F3) with a depth of ∼238 m in August 2019 has been crucial for providing insights into the complex system of Hartoušov Mofette. © Copyright © 2021 Daskalopoulou, Woith, Zimmer, Niedermann, Barth, Frank, Vieth-Hillebrand, Vlček, Bağ and Bauz. Article 2021 English 22966463 10.3389/feart.2021.615766 Frontiers in Earth Science 9 Frontiers Media S.A. Cheb Basin; Czech Republic; Karlovarsky; Atmospheric movements; Boreholes; Chemical analysis; Earthquakes; Inert gases; Isotopes; Solubility; Atmospheric contributions; Chemical compositions; Chemical concentrations; CO2 concentration; Crustal earthquakes; Isotope compositions; Monitoring stations; Sampling campaigns; carbon; carbon dioxide; carbon flux; concentration (composition); degassing; helium; isotopic composition; magma; mantle structure; solubility; Carbon dioxide https://www.scopus.com/inward/record.uri?eid=2-s2.0-85104633463&doi=10.3389%2ffeart.2021.615766&partnerID=40&md5=cc9df0aed8ef6b1d4e6b3ec7da6cac66 Cited by: 3; All Open Access, Gold Open Access, Green Open Access Kyriaki Daskalopoulou Heiko Woith Martin Zimmer Samuel Niedermann Johannes A. C. Barth Alexander H. Frank Andrea Vieth-Hillebrand Josef Vlček Cemile Dilara Bağ Ralf Bauz article Schaebitz2021 Article 2021 10.1038/s43247-021-00195-7 Communications Earth and Environment 2 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85116444064&doi=10.1038%2fs43247-021-00195-7&partnerID=40&md5=b5503d710f2f4ef71e1adf387da693f9 Cited by: 47; All Open Access, Gold Open Access, Green Open Access Frank Schaebitz Asfawossen Asrat Henry F. Lamb Andrew S. Cohen Verena Foerster Walter Duesing Stefanie Kaboth-Bahr Stephan Opitz Finn A. Viehberg Ralf Vogelsang Jonathan Dean Melanie J. Leng Annett Junginger Christopher Bronk Ramsey Melissa S. Chapot Alan Deino Christine S. Lane Helen M. Roberts Céline Vidal Ralph Tiedemann Martin H. Trauth article Kring20211547 A sulfate-reducing population of thermophiles grew in porous, permeable niches within glass-bearing impact breccias of the Chicxulub impact crater. The microbial community grew in an impact-generated hydrothermal system that vented on the seafloor several hundred meters beneath the sea surface. Potential electron donors for that metabolism are hydrocarbons, although a strong C-isotope signature of that source does not exist. Model calculations explored here suggest that alteration of glass within the impact breccias may have produced H2 in sufficient quantities for population growth as the hydrothermal system cooled through thermophilic temperatures, although it is sensitive to the oxidation state of iron in the melt rock prior to hydrothermal alteration and the secondary mineral assemblage. At high water-to-rock ratios and temperatures below 45°C, H2 yields are insufficient to maintain a population of hydrogenotrophic sulfate-reducing bacteria, but yields double with a higher proportion of ferrous iron between 45 and 65°C. The most reduced rocks (i.e., highest proportion of ferrous iron) that are allowed to form andradite, which is observed in core samples, produce copious amounts of H2 in the temperature window for thermophiles and hyperthermophiles. Mixtures of melt rock and carbonate, which is observed in breccia matrices, produce somewhat less H2, and the onset of massive H2 production is shifted to higher temperatures (i.e., lower W/R). © Copyright 2021, Mary Ann Liebert, Inc., publishers 2021. 2021 10.1089/ast.2021.0045 Astrobiology 21 1547-1564 Lunar and Planetary Institute, Universities Space Research Association, Houston, Texas, United States; Geoscience Department and MARUM, Center for Marine Environmental Sciences, Universität Bremen, Bremen, Germany 12 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85121355110&doi=10.1089%2fast.2021.0045&partnerID=40&md5=967ef120fc982d73f5dff3bd1f3658a2 cited By 1 D.A. Kring W. Bach article Rinat2021917 Article 2021 10.5194/nhess-21-917-2021 Natural Hazards and Earth System Sciences 21 917 – 939 3 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85102368181&doi=10.5194%2fnhess-21-917-2021&partnerID=40&md5=ade02ff218d9ab591c8e41c474fb24d1 Cited by: 25; All Open Access, Gold Open Access, Green Open Access Yair Rinat Francesco Marra Moshe Armon Asher Metzger Yoav Levi Pavel Khain Elyakom Vadislavsky Marcelo Rosensaft Efrat Morin article greenberger2021hydrothermal Processes for formation, cooling, and altering Earth's ocean crust are not yet completely understood due to challenges in access and sampling. Here, we use contiguous micro-imaging infrared spectroscopy to develop complete-core maps of mineral occurrence and investigate spatial patterns in the hydrothermal alteration of 1.2 km of oceanic crust recovered from Oman Drilling Project Holes GT1A, GT2A, and GT3A drilled in the Samail Ophiolite, Oman. The imaging spectrometer shortwave infrared sensor measured reflectance of light at wavelengths 1.0–2.6 μm at 250–260 μm/pixel, resulting in >1 billion independent measurements. We map distributions of nine key primary and secondary minerals/mineral groups—clinopyroxene, amphibole, calcite, chlorite, epidote, gypsum, kaolinite/montmorillonite, prehnite, and zeolite—and find differences in their spatial occurrences and pervasiveness. Accuracy of spectral mapping of occurrence is 68%–100%, established using X-ray diffraction measurements from the core description. The sheeted dikes and gabbros of upper oceanic crust Hole GT3A show more pervasive alteration and alteration dominated by chlorite, amphibole, and epidote. The foliated/layered gabbros of GT2A from intermediate crustal depths have similarly widespread chlorite but more zeolite and little amphibole and epidote. The layered gabbros of the lower oceanic crust (GT1A) have remnant pyroxene and 2X less chlorite, but alteration is extensive within and surrounding major fault zones with widespread occurrences of amphibole. The results indicate greater distribution of higher temperature alteration minerals in the upper oceanic crust relative to deeper gabbros and highlight the importance of fault zones in hydrothermal convection in the lower ocean crust. © 2021. The Authors. 2021 English 21699313 10.1029/2021JB021976 Journal of Geophysical Research: Solid Earth 126 Wiley Online Library e2021JB021976 Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, United States; School of Geography, Earth, and Environmental Sciences, Plymouth University, Plymouth, United Kingdom; Department of Earth & Environmental Sciences, Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY, United States; Department of Earth, Planetary, and Space Sciences, University of California, Los Angeles, CA, United States; School of Ocean and Earth Science, National Oceanography Centre Southampton, University of Southampton, Southampton, United Kingdom 8 dike; gabbro; hydrothermal alteration; imaging method; infrared spectroscopy; mineralization; multispectral image; oceanic crust, Oman https://www.scopus.com/inward/record.uri?eid=2-s2.0-85113707133&doi=10.1029%2f2021JB021976&partnerID=40&md5=5a190e54bd64b6846029a4400c00e8c4 cited By 3 Rebecca N Greenberger Michelle Harris Bethany L Ehlmann Molly A Crotteau Peter B Kelemen Craig E Manning Damon AH Teagle Oman Drilling Project Science Team article Ortiz-Aleman202155 Large impact structures are characterized by peak ring and central uplifts with lateral/vertical mass transport during late formation stages. Here we investigate the Chicxulub crater, which has been surveyed by an array of marine, aerial and land-borne geophysical methods. Seismic reflection surveys in its central sector have shown lack of resolution, making it difficult to image the central uplift. We develop an integrated seismic and gravity model for the structural elements, imaging the central uplift and melt and breccia units. The 3D velocity model built from interpolation of seismic data is validated using perfectly matched layer seismic acoustic wave propagation modeling, optimized at grazing incidence using the shift in the frequency domain. Modeling shows that lack of illumination relates to seismic energy that remains trapped in an upper low-velocity zone corresponding to the carbonate sediments, upper melt/breccias and surrounding faulted blocks. After conversion of seismic velocities into a volume of density values, we apply parallel forward gravity modeling to constrain the size and shape of the central uplift, which has a ~ 40 km diameter concave upwards top lying at ~ 3.5–4.5 km depth. The preferred model provides a high-resolution image of crater units and structure. The gravity response of modeled units shows asymmetries in structure and the distribution of breccias, melt and target carbonates. Finally, we apply an adjoint reverse time migration approach for seismic imaging using the density and velocity models built for the acoustic wave propagation and gravity modeling, which allows improved modeling of the crater structure. © 2021, Springer Nature Switzerland AG. 2021 10.1007/s00024-020-02638-2 Pure and Applied Geophysics 178 55-77 Litoteca Nacional de Hidrocarburos Sede Merida, Parque Cientifico y Tecnologico de Yucatan, Sierra Papacal, Mérida, Yucatán, Mexico; Laboratoire GET/Géosciences Environnement Toulouse, UMR CNRS 5563, Observatoire Midi Pyrénées, Université Paul Sabatier, 14 avenue Edouard Belin, Toulouse, 31400, France; Programa de Perforaciones en Océanos y Continentes, Instituto de Geofisica, Universidad Nacional Autónoma de Mexico, Coyoacan, Mexico City, 04510, Mexico; Instituto de Investigaciòn Cientìfica y Estudios Avanzados Chicxulub, Parque Cientifico y Tecnologico de Yucatan, Sierra Papacal, Mérida, Yucatán 97302, Mexico; Tecnológico Nacional de México/IT de Mérida, Departamento de Sistemas y Computación, Mérida, Yucatán, Mexico 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85099082352&doi=10.1007%2fs00024-020-02638-2&partnerID=40&md5=85a68c903744118862c97f6fe41568be cited By 2 C. Ortiz-Aleman R. Martin J. Urrutia-Fucugauchi M.O. Castillo M. Nava-Flores article kelemen2021initial 2021 Journal of Geophysical Research: Solid Earth 126 Wiley Online Library e2021JB022729 12 Peter B Kelemen James A Leong Juan Obeso Jürg M Matter Eric T Ellison Alexis Templeton Daniel B Nothaft Alireza Eslami Katy Evans Marguerite Godard others article Sheppard2021 Iron is the most abundant redox-sensitive element on the Earth's surface, and the oxidation state, mineral host, and crystallinity of Fe-rich phases in sedimentary systems can record details of water-rock interactions and environmental conditions. However, we lack a complete understanding of how these Fe-rich materials are created, maintained, and oxidized or reduced in sedimentary environments, particularly those with mafic sources. The catchment of Lake Towuti, Indonesia, is known to contain a wide range of abundant crystalline Fe oxide, and the lake has a long sedimentary history. Here, we study a ∼100 m long drill core from the lake to understand patterns of sedimentation and how young iron-rich sediments are affected by diagenesis through geologic time. We use visible/near infrared and Mössbauer spectroscopy, X-ray diffraction, bulk chemistry measurements, and statistical cluster analysis to characterize the core sediment. We find that the core sediment can be divided into three statistically different zones dominated by Mg serpentine, Al clay minerals, and Fe2+ carbonate, respectively. The entire core is rich in nanophase Fe, and elemental correlations and Fe mineralogy vary between these zones. The nanophase Fe is highly complex with both ferrous and ferric components, and contributes to, but does not dictate, variations in sediment color. We propose that the distinctive zones are the result of structural basin changes (notably river capture and shifting drainage patterns), and diagenetic overprinting caused by deep burial of reactive Fe. This complex record has implications for disentangling depositional and diagenetic trends in other mafic lacustrine systems. © 2021. American Geophysical Union. All Rights Reserved. Article 2021 English 15252027 10.1029/2020GC009582 Geochemistry, Geophysics, Geosystems 22 John Wiley and Sons Inc 8 Greater Sunda Islands; Lake Towuti; Malili Lakes; South Sulawesi; Sulawesi; Sunda Isles; Catchments; Chemical analysis; Cluster analysis; Crystallinity; Drills; Infill drilling; Iron oxides; Lakes; Nanocrystalline materials; Runoff; Sedimentary rocks; Sedimentology; Sediments; Serpentine; Drainage patterns; Environmental conditions; Lacustrine systems; Redox sensitives; Sedimentary environment; Sedimentary systems; Visible/near infrared; Water rock interactions; diagenesis; iron oxide; lacustrine deposit; mineralogy; sediment chemistry; sediment core; sedimentation; Core drilling https://www.scopus.com/inward/record.uri?eid=2-s2.0-85113753437&doi=10.1029%2f2020GC009582&partnerID=40&md5=20c2e0e060f5681bfadd583832697d3a Cited by: 0; All Open Access, Bronze Open Access, Green Open Access Rachel Y. Sheppard Ralph E. Milliken James M. Russell Elizabeth C. Sklute M. Darby Dyar Satria Bijaksana Ascelina K. M. Hasberg Marina A. Morlock article klaessens2021highly Dunites in ophiolites form by pyroxene dissolution and olivine precipitation during melt-peridotite interaction. We present structural and geochemical data on peridotites from the Batin region (Wadi Tayin massif) of the Oman ophiolite, where an exceptionally large (∼9.5 km long) dunite body was sampled by the ICDP Oman Drilling Project (BA4A borehole). 900–1,200 m beneath the petrological Moho, this dunite is overlain by harzburgite hosting pyroxene-depleted and pyroxene-rich bands. Highly siderophile elements (HSEs) and Os isotopes, excellent tracers of melt flow through peridotites, were measured in dunites and interspersed harzburgites from BA4A borehole. The Batin dunite is structurally and chemically distinct from dunites from the Moho Transition Zone and basal section of the ophiolite, resembling instead sparse dunite veins in the main mantle section. Batin dunites have fairly uniform Os, Ir, and Ru abundances, but Pd and Pt contents increasing with depth. One deep dunite sample has initial 187Os/188Os more radiogenic than MORB. Though the limited number of data demands prudence, we suggest that the Batin dunite formed from a large pulse of radiogenic melts, whose flow was impeded ∼1,200 m below the Moho. As these melts ascended, they may have lost their radiogenic character and relative Pt and Pd enrichment through interaction with peridotites, which have much higher HSE contents than melts. Such interaction would also diminish the under-saturation in pyroxene of the melts, eliminating their capacity to sufficiently dissolve the pyroxene of the host harzburgite to form dunite, thus explaining the upper limit of the dunite at ∼900 m. © 2021. American Geophysical Union. All Rights Reserved. 2021 English 21699313 10.1029/2021JB021977 Journal of Geophysical Research: Solid Earth 126 Wiley Online Library e2021JB021977 Centre de Recherches Pétrographiques et Géochimiques, UMR 7358 CNRS - Université de Lorraine, Vandoeuvre-lès-Nancy, France 10 dunite; mantle structure; ophiolite; osmium isotope; siderophile element https://www.scopus.com/inward/record.uri?eid=2-s2.0-85118436454&doi=10.1029%2f2021JB021977&partnerID=40&md5=874d823a1f7285f042ee993403e2b572 cited By 0 Delphine Klaessens Laurie Reisberg David Jousselin Oman Drilling Project Science Team article Leet20211137 Sedimentary cherts, with well-preserved microfossils, are known from the Archean to the present, yet their origins remain poorly understood. Lake Magadi, Kenya, has been used as a modern analog system for understanding the origins of nonbiogenic chert. We present evidence for synsedimentary formation of Magadi cherts directly from siliceous gels. Petrographic thin-section analysis and field-emission scanning electron microscopy of cherts from cores drilled in Lake Magadi during the Hominin Sites and Paleolakes Drilling Project in 2014 led to the discovery of two-dimensional branching “labyrinth patterns” in chert, which are a type of fractal “squeeze” pattern formed at air-liquid interfaces. Labyrinth patterns preserved in chert from Lake Magadi cores indicate invasion of air along planes in dewatering gels. These patterns support the precipitation of silica gels in the saline-alkaline Lake Magadi system and syndepositional drying of gels in contact with air as part of chert formation. Recognizing cherts as syndepositional has been critical for our use of them for U-Th dating. Identification of labyrinth patterns in ancient cherts can provide a better understanding of paleoenvironmental and geochemical conditions in the past © 2021 Geological Society of America. For permission to copy, contact editing@geosociety.org. Article 2021 English 00917613 10.1130/G48774.1 Geology 49 Geological Society of America 1137 – 1142 9 Kajiado; Kenya; Lake Magadi; Binary alloys; Field emission microscopes; Infill drilling; Lakes; Phase interfaces; Scanning electron microscopy; Silica; Silica gel; Thorium alloys; Thorium metallography; Uranium alloys; Uranium metallography; Air liquid interfaces; Analog systems; Drilling projects; Field emission scanning electron microscopy; Geochemical conditions; Microfossils; Synsedimentary; Thin section; Archean; chert; depositional environment; microfossil; paleolimnology; petrography; precipitation (chemistry); silica; Gels https://www.scopus.com/inward/record.uri?eid=2-s2.0-85114425508&doi=10.1130%2fG48774.1&partnerID=40&md5=437f85741566bb804901d9533cd01588 Cited by: 4; All Open Access, Green Open Access Kennie Leet Tim K. Lowenstein Robin W. Renaut R. Bernhart Owen Andrew Cohen article Leicher2021 Data paper 2021 10.1038/s41597-021-01013-7 Scientific Data 8 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85114508324&doi=10.1038%2fs41597-021-01013-7&partnerID=40&md5=b9632a4f54653e00b96a636c6bf2d158 Cited by: 20; All Open Access, Gold Open Access, Green Open Access Niklas Leicher Biagio Giaccio Giovanni Zanchetta Roberto Sulpizio Paul G. Albert Emma L. Tomlinson Markus Lagos Alexander Francke Bernd Wagner article Vakhrameeva2021 Direct correlations between terrestrial and marine climate-proxy records are essential in order to determine potential lead/lag relationships in the response of the terrestrial and marine realms to climate forcing. In the Eastern Mediterranean region, such land-sea correlations have not yet been established beyond c. 200 ka. To explore the potential of tephra layers for Late and Middle Pleistocene land-sea correlations in the Eastern Mediterranean region, we have revisited yet unconfirmed tephra layers previously reported from Ocean Drilling Program (ODP) Site 964 (Ionian Basin) for the past c. 800 kyr in order to identify their origin and examine potential terrestrial counterparts. Using major- and trace-element glass analyses, we confirmed the presence of seven visible tephra layers with ages from 623 to 38 ka. These tephra layers represent known tephra isochrons from Italian volcanic centers (Y-5, Y-7, X-6, and V-0) and three yet unknown eruptions from Etna (623 ka), the Campanian Volcanic Zone (CVZ; 238 ka), and Pantelleria (238 ka). Because the majority of the previously reported tephra layers from ODP Site 964 were identified as clastic layers of non-volcanic origin, cryptotephra analyses were carried out for cores spanning Marine Isotope Stages (MIS) 13 to 9 (500–320 ka). This effort yielded 19 cryptotephra layers originating from Santorini volcano, the CVZ, possibly Roccamonfina volcano, and an undefined source in either the Aeolian Islands or the South Aegean Volcanic Arc. Two tephra layers are correlated with potential equivalents from terrestrial archives on the Italian and Balkan Peninsulas, including tephra isochrons SC5/A7/OH-DP-1966 (c. 493 ka; Mercure basin, Acerno basin, and Lake Ohrid) and TP09–65.95 (c. 359 ka; Tenaghi Philippon) that represent an unknown eruption of Roccamonfina and the Cape Therma 1 eruption of Santorini, respectively. Direct linking of the marine record from ODP Site 964 with the terrestrial records from Tenaghi Philippon, Lake Ohrid, and the Acerno basin via tephra tie points allowed us to circumvent shortcomings of the individual age models, and to obtain a comprehensive picture of climate variability in the greater Eastern Mediterranean region for the MIS 13–9 interval. © 2021 Elsevier Ltd Article 2021 English 02773791 10.1016/j.quascirev.2021.106811 Quaternary Science Reviews 255 Elsevier Ltd Balkans; Catania [Sicily]; Central Macedonia; Cyclades; Etna; Greece; Italy; Lake Ohrid; Lipari Islands; Messina [Sicily]; Pantelleria; Santorin; Santorini [Southern Aegean]; Serrai [Central Macedonia]; Sicily; Southern Aegean; Tenaghi Philippon; Trapani; Lakes; Trace elements; Volcanoes; Climate variability; Eastern Mediterranean; Land-sea correlations; Major and trace elements; Marine isotope stages; Middle Pleistocene; Ocean drilling programs; South Aegean volcanic arc; Campanian; marine record; Mediterranean environment; Ocean Drilling Program; proxy climate record; tephra; tephrochronology; volcanic eruption; volcanic glass; volcanic island; Climate models https://www.scopus.com/inward/record.uri?eid=2-s2.0-85100519027&doi=10.1016%2fj.quascirev.2021.106811&partnerID=40&md5=f61a833ff881cf0cc484a59ef073cae1 Cited by: 6; All Open Access, Green Open Access Polina Vakhrameeva Andreas Koutsodendris Sabine Wulf Maxim Portnyagin Oona Appelt Thomas Ludwig Mario Trieloff Jörg Pross article Allstädt2021177 Marked by the expansion of ice sheets in the high latitudes, the intensification of Northern Hemisphere glaciation across the Plio/Pleistocene transition at ~ 2.7 Ma represents a critical interval of late Neogene climate evolution. To date, the characteristics of climate change in North America during that time and its imprint on vegetation has remained poorly constrained because of the lack of continuous, highly resolved terrestrial records. We here assess the vegetation dynamics in northwestern North America during the late Pliocene and early Pleistocene (c. 2.8–2.4 Ma) based on a pollen record from a lacustrine sequence from paleo-Lake Idaho, western Snake River Plain (USA) that has been retrieved within the framework of an International Continental Drilling Program (ICDP) coring campaign. Our data indicate a sensitive response of forest ecosystems to glacial/interglacial variability paced by orbital obliquity across the study interval, and also highlight a distinct expansion of steppic elements that likely occurs during the first strong glacial of the Pleistocene, i.e. Marine Isotope Stage 100. The pollen data document a major forest biome change at ~ 2.6 Ma that is marked by the replacement of conifer-dominated forests by open mixed forests. Quantitative pollen-based climate estimates suggest that this forest reorganisation was associated with an increase in precipitation from the late Pliocene to the early Pleistocene. We attribute this shift to an enhanced moisture transport from the subarctic Pacific Ocean to North America, confirming the hypothesis that ocean-circulation changes were instrumental in the intensification of Northern Hemisphere glaciation. © 2021, The Author(s). 2021 English 18671594 10.1007/s12549-020-00460-1 Palaeobiodiversity and Palaeoenvironments 101 Springer Science and Business Media Deutschland GmbH 177-195 Institute of Earth Sciences, Heidelberg University, Im Neuenheimer Feld 234–236, Heidelberg, 69120, Germany; Department of Geosciences, University of Tübingen, Hölderlinstraße 12, Tübingen, 72074, Germany; Department of Geosciences, University of Connecticut, 354 Mansfield Road, Storrs, CT 06269, United States; Institute of Geosciences, University of Potsdam, Karl-Liebknecht-Straße 24-26, Potsdam-Golm, 14467, Germany; Institute of Geology and Mineralogy, University of Cologne, Zülpicherstr. 49a, Cologne, 50674, Germany 1 climate effect; climate variation; drilling; glaciation; ice sheet; Neogene; palynology; Pliocene-Pleistocene boundary; proxy climate record; vegetation dynamics, Idaho; North America; Pacific Ocean; Snake River Plain; United States, Coniferophyta https://www.scopus.com/inward/record.uri?eid=2-s2.0-85099108452&doi=10.1007%2fs12549-020-00460-1&partnerID=40&md5=6a1c414e97ff9df8f59b81129feccbfe cited By 4 F.J. Allstädt A. Koutsodendris E. Appel W. Rösler T. Reichgelt S. Kaboth-Bahr A.A. Prokopenko J. Pross article Qin2024168 Article 2021 10.12143/j.ztgc.2021.12.001 Drilling Engineering 48 1-6 12 Q. Xue N. Liang L. Han S. Ma K. Wang article Huang2021 Subduction of the Paleo-Pacific and Mongol–Okhotsk oceanic plates is widely believed to have caused extensive Mesozoic magmatism and lithospheric deformation in East Asia. However, it remains unclear how the two tectonic domains affected NE China, and whether a boundary exists between them, because the Songnen Block in central NE China is covered by sedimentary rocks and the related mafic magmatism has been rarely discovered. Here we report a suite of Early Jurassic (ca. 175 Ma) mafic volcanic rocks (including basalt and basaltic andesite) from the Sk2 Borehole, Songliao Basin, NE China. The Sk2 mafic rocks are characterized by high Th/U, Zr/Y and Ti/Y ratios, and their geochemical signatures are consistent with formation in a back-arc extensional setting, rather than an arc setting. The rocks show depleted zircon εHf(t) and whole-rock εNd(t) values, which are comparable to mafic rocks located on the east of the Songliao Basin. This suggests that they both have a depleted mantle source, unlike the mafic rocks on the west of the Songliao Basin with relatively enriched Nd and Hf isotopes. Early–Middle Jurassic mafic rocks are distributed in the Erguna Block, &gt;500 km to the west from the Sk2 Borehole, whereas coeval mafic rocks are widely distributed in the nearby eastern Heilongjiang and Jilin provinces. These intraplate-like mafic rocks and the Early Jurassic bimodal rocks within the Lesser Xing'an and Zhangguangcai ranges likely formed in response to lithospheric extension that was triggered by subduction of the Paleo-Pacific Plate. The Early Jurassic mafic rocks directly underlie the oldest sedimentary rocks (the Huoshiling Formation) in the Songliao Basin, which suggests that basin formation was probably initiated by lithospheric extension. © 2020 Elsevier B.V. Article 2021 English 00244937 10.1016/j.lithos.2020.105871 Lithos 380-381 Elsevier B.V. State Key Laboratory of Geological Processes and Mineral Resources, and School of Earth Science and Resources, China University of Geosciences, Beijing, 100083, China; Guangxi Key Laboratory of Hidden Metallic Ore Deposits Exploration, Guilin University of Technology, Guilin, 541004, China; Key Lab of Submarine Geosciences and Prospecting Techniques, MOE, College of Marine Geosciences, Ocean University of China, Qingdao, 266100, China; State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Wuhan, 430074, China; State Key Laboratory of Geological Processes and Mineral Resources, Institute of Earth Sciences, China University of Geosciences, Beijing, 100083, China borehole; deformation mechanism; extensional tectonics; intraplate process; Jurassic; lithospheric structure; Pacific plate; paleogeography; plate tectonics; subduction zone; tectonic evolution; tectonic setting; volcanic rock, China; Mongol-Okhotsk Fold Belt; Songliao Basin https://www.scopus.com/inward/record.uri?eid=2-s2.0-85096496849&doi=10.1016%2fj.lithos.2020.105871&partnerID=40&md5=ab42adc8efa30f76b12431eb74494edf Cited by: 26; All Open Access, Bronze Open Access Feng Huang Zhao Zhang Jifeng Xu Xiyao Li Yunchuan Zeng Rong Xu Xijun Liu Liying Zhang Man Zhang Changqi Yang Liangliang Zhang Hongxia Yu Xuli Yang article crotteau2021hydration 2021 CaltechDATA Molly A Crotteau Rebecca N Greenberger Bethany L Ehlmann George R Rossman Michelle Harris Peter B Kelemen Damon AH Teagle others article Pieńkowski2021 Article 2021 10.1016/j.gloplacha.2021.103648 Global and Planetary Change 207 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85116900018&doi=10.1016%2fj.gloplacha.2021.103648&partnerID=40&md5=d54ba925e33a113f7f1d4105e2e1dcc5 Cited by: 17; All Open Access, Green Open Access Grzegorz Pieńkowski Alfred Uchman Krzysztof Ninard Stephen P. Hesselbo article Liu2021 A high-resolution seismic reflection survey has been conducted across the Insubric Line from the Sesia Zone into the Ivrea-Verbano Zone (IVZ), where a remarkably complete cross-section of lower continental crust is exposed. The survey was carried out in preparation for the DIVE (Drilling the Ivrea-Verbano zonE) project, which was recently approved by the International Continental Scientific Drilling Program (ICDP). DIVE aims to gain new insights into the characteristics of the lower continental crust through targeted drilling, sampling, and borehole logging. A key borehole is planned near the Insubric Line at Balmuccia, where the deepest parts of the lower continental crust are exposed. As such, the primary objective of this seismic survey was to explore whether the sub-vertical structures prevailing at the surface can be expected to continue at depth or whether there are any indications for major flattening or fault-related offsets. Correspondingly, the acquisition and processing of the seismic reflection data were geared towards revealing weak backscattered events from local heterogeneities associated with the prevailing sub-vertical structural grain. The migrated sections, contain coherent backscattered events to a depth of ~1 km, which form numerous short lineaments that seem to align sub-vertically. To substantiate this observation, we have generated synthetic seismic reflection surveys for canonical models of sub-vertical structures associated with Gaussian- and binary-distributed heterogeneities. Both the observed and synthetic seismic data were then subjected to energy-based attribute analysis as well as geostatistical estimations of the structural aspect ratios and the associated dips. The results of these quantitative interpretation approaches are indicative of the overall consistency between the synthetic and the observed seismic data and, hence, support the original qualitative interpretation of the latter in that the sub-vertical structural grain evident at the surface seems to prevail throughout the imaged part of the upper crust. © 2021 The Authors Article 2021 English 00401951 10.1016/j.tecto.2021.229035 Tectonophysics 816 Elsevier B.V. Italy; Ivrea-Verbano Zone; Aspect ratio; Boreholes; Geological surveys; Infill drilling; Seismic prospecting; Seismic response; Well logging; Continental scientific drillings; Geostatistical estimation; High resolution seismic; Local heterogeneity; Quantitative interpretation; Seismic reflection data; Seismic reflection survey; Vertical structures; fault zone; geostatistics; hard rock; seismic reflection; seismic response; seismic survey; structural response; Seismic waves https://www.scopus.com/inward/record.uri?eid=2-s2.0-85113688936&doi=10.1016%2fj.tecto.2021.229035&partnerID=40&md5=6b597d2d54dd1586b2b3ed490492b72f Cited by: 1; All Open Access, Green Open Access, Hybrid Gold Open Access Yu Liu Andrew Greenwood György Hetényi Ludovic Baron Klaus Holliger conference Guglielmi2021 Conference paper 2021 55th U.S. Rock Mechanics / Geomechanics Symposium 2021 5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85123352503&partnerID=40&md5=463ea1a31bc52cdb588642e1f874c250 Cited by: 3 Y. Guglielmi P. Cook F. Soom P. Dobson T. Kneafsey B. Valley M. Kakurina A. Niemi C.F. Tsang A. Tatomir C. Juhlin F. Basirat article Westover2021 Kenya's Baringo-Tugen Hills-Barsemoi drill site is one of six localities across Kenya and Ethiopia from which the Hominin Sites and Paleolakes Drilling Project has obtained sediment cores in an effort to investigate the role of environmental forcing in shaping human evolution. The Baringo Basin site features extensive exposures of the Chemeron Formation, which contains >100 fossil vertebrate localities including five hominin sites. The 228-m drill core, dating from ~3.29 to 2.56 Ma, is characterized by fluvio-lacustrine sediments, including multiple diatomites, with evidence of variable degrees of later pedogenic modification. In the lower part of the core (~3.29–3.04 Ma), diatoms were preserved only in very low abundance, consistent with predominantly fluvial or lake marginal environments. In contrast, five diatomites and two additional diatom-rich intervals were deposited after ~3.04 Ma, reflecting a major shift in the basin hydrology. Planktonic freshwater species dominated these diatom-rich intervals, whereas periphytic taxa were present in proportions less than 2%, suggesting that these intervals represent open-water deposition during lake highstands. Littoral or saline assemblages are largely absent throughout the core. Instead, we observed a pattern of increasing diatom frustule dissolution at the tops and bottoms of diatomite units, indicating increased alkalinity during the transgressive/regressive phases. A Na-bearing zeolite (analcime) indicative of saline waters precipitated in clastic-dominated intervals between diatomites, suggesting extreme environmental variability between lake highstands and lowstands. Diatom assemblages were consistently dominated by a few species belonging to the genera Aulacoseira and Stephanodiscus, which were at times co-dominant. We infer that assemblages dominated by Aulacoseira represent a well-mixed lake with abundant supply of silica. When Stephanodiscus was dominant, which occurred more frequently in the later freshwater phases, we infer incomplete mixing and reduced silica flux to the epilimnion (upper water layer). © 2019 Elsevier B.V. Article 2021 English 00310182 10.1016/j.palaeo.2019.109382 Palaeogeography, Palaeoclimatology, Palaeoecology 570 Elsevier B.V. Baringo; Ethiopia; Kenya; Tugen Hills; Aulacoseira; Bacillariophyta; Stephanodiscus; Vertebrata; alkalinity; diatom; diatomite; fluvial deposit; fossil assemblage; lacustrine deposit; paleolimnology; Pliocene; sediment core https://www.scopus.com/inward/record.uri?eid=2-s2.0-85076866115&doi=10.1016%2fj.palaeo.2019.109382&partnerID=40&md5=caf7c1c432cbca104504483365814e6c Cited by: 6; All Open Access, Bronze Open Access Karlyn S. Westover Jeffery R. Stone Chad L. Yost Jennifer J. Scott Andrew S. Cohen Nathan M. Rabideaux Mona Stockhecke John D. Kingston article Goderis2021 The Cretaceous-Paleogene (K-Pg) mass extinction is marked globally by elevated concentrations of iridium, emplaced by a hypervelocity impact event 66 million years ago. Here, we report new data from four independent laboratories that reveal a positive iridium anomaly within the peak-ring sequence of the Chicxulub impact structure, in drill core recovered by IODP-ICDP Expedition 364. The highest concentration of ultrafine meteoritic matter occurs in the post-impact sediments that cover the crater peak ring, just below the lowermost Danian pelagic limestone. Within years to decades after the impact event, this part of the Chicxulub impact basin returned to a relatively low-energy depositional environment, recording in unprecedented detail the recovery of life during the succeeding millennia. The iridium layer provides a key temporal horizon precisely linking Chicxulub to K-Pg boundary sections worldwide. Copyright © 2021 The Authors, some rights reserved. 2021 10.1126/sciadv.abe3647 Science Advances 7 Analytical, Environmental, and Geochemistry, Vrije Universiteit Brussel, Brussels, Belgium; Department of Geosciences, University of Padova, Padova, Italy; Sub-marine Resources Research Center, Research Institute for Marine Resources Utilization, Japan Agency for Marine-Earth Science and Technology, Kanagawa, Japan; Natural History Museum, Vienna, Austria; Astrogeobiology Laboratory, Division of Nuclear Physics, Department of Physics, Lund University, Lund, Sweden; Depart-ment of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, IN, United States; Laboratoire G-Time, Université Libre de Bruxelles, Brussels, Belgium; Department of Geology, KU Leuven, Leuven, Belgium; Eyring Materials Center, Arizona State University, Tempe, AZ, United States; Department of Lithospheric Research, University of Vienna, Vienna, Austria; Institut für Geologie und Mineralogie, Universität zu Köln, Köln, Germany; Atomic and Mass Spectrometry-A&MS research group, Department of Chemistry, Ghent University, Ghent, Belgium; Department of Earth Sciences, Utrecht University, Utrecht, Netherlands; Depart-ment of Earth and Planetary Sciences, Tokyo Institute of Technology, Tokyo, Japan; Department of Earth, Ocean and Atmospheric Science and National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL, United States; HNU Neu-Ulm University of Applied Sciences, Neu-Ulm, Germany; Lunar and Planetary Institute-USRA, Houston, TX, United States; Department of Earth Sciences, Durham University, Durham, United Kingdom; Department of Geosciences, Pennsylvania State University, University Park, PA, United States; Institute for Geophysics, University of Texas at Austin, Austin, TX, United States; Department of Geological Sciences, University of Texas at Austin, Austin, TX, United States; Center for Planetary Systems Habitability, University of Texas, Austin, TX, United States; Department of Earth Science and Engineering, Imperial College London, London, United Kingdom; Department of Earth Sciences, Vrije Universiteit Amsterdam, Amsterdam, Netherlands; Depart-ment of Geosciences, University of Alaska Fairbanks, Fairbanks, AK, United States 9 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85102098183&doi=10.1126%2fsciadv.abe3647&partnerID=40&md5=4c9345ae7f6088338602dfb83ae92121 cited By 24 S. Goderis H. Sato L. Ferrière B. Schmitz D. Burney P. Kaskes J. Vellekoop A. Wittmann T. Schulz S.M. Chernonozhkin P. Claeys S.J. Graaff T. Déhais N.J. Winter M. Elfman J.-G. Feignon A. Ishikawa C. Koeberl P. Kristiansson C.R. Neal J.D. Owens M. Schmieder M. Sinnesael F. Vanhaecke S.J.M. Malderen T.J. Bralower S.P.S. Gulick D.A. Kring C.M. Lowery J.V. Morgan J. Smit M.T. Whalen IODP-ICDP Expedition 364 Scientists article Cvetkoska2021 Article 2021 10.1016/j.quascirev.2021.107046 Quaternary Science Reviews 265 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85109072846&doi=10.1016%2fj.quascirev.2021.107046&partnerID=40&md5=249ba53eb1524150d6e27c8661df7583 Cited by: 7; All Open Access, Green Open Access, Hybrid Gold Open Access Aleksandra Cvetkoska Elena Jovanovska Torsten Hauffe Timme H. Donders Zlatko Levkov Dedmer B. Waal Jane M. Reed Alexander Francke Hendrik Vogel Thomas Wilke Bernd Wagner Friederike Wagner-Cremer article hatakeyama2021effects 2021 Journal of Geophysical Research: Solid Earth 126 Wiley Online Library e2021JB021923 11 Kohei Hatakeyama Ikuo Katayama Natsue Abe Keishi Okazaki Katsuyoshi Michibayashi Oman Drilling Project Science Party article Zhao2021 Class II hydrate deposits are characterized by a mobile water zone (WZ) underneath the hydrate-bearing layer (HBL) and are encountered in permafrost and deep-sea sediments. In this work, an efficient method of depressurization combining low-frequency electric heating under dual horizontal wells is proposed to exploit Class II hydrate deposits, in which two parallel horizontal wells are arranged in the HBL and the WZ. Based on the geological parameters in the Mallik deposit, the energy recovery behaviors are studied through a numerical simulation approach. Electric heating significantly improves hydrate dissociation and gas production compared with the depressurization method. However, gas production lags electric heating for a long time, and the energy efficiency ratio decreases with time in the later stage. To address these shortcomings, two additional electric heating schemes are designed and optimized. The results show that the additional wellbore heating at the beginning of production accelerates the dissociation of hydrates near the production well, thus greatly reducing the lag time. When electric heating is terminated after the 800th day, the cumulative gas production is reduced by 9.1%, but the energy efficiency ratio is improved as high as 48.71, which confirms the great potential of the proposed method. © 2021 Elsevier Ltd 2021 English 03605442 10.1016/j.energy.2021.121137 Energy 233 Elsevier Ltd Key Laboratory of Unconventional Oil & Gas Development (China University of Petroleum (East China)), Ministry of Education, Qingdao, 266580, China; Laboratory for Marine Mineral Resources, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237, China; School of Petroleum Engineering, China University of Petroleum (East China), Qingdao, 266580, China Dissociation; Electric heating; Energy efficiency; Gas hydrates; Horizontal wells; Hydration, Class II; Depressurizations; Electrical heating; Energy; Energy recovery; Gas productions; Hydrate deposit; Lower frequencies; Thermal stimulation; Water zone, Deposits, energy efficiency; gas hydrate; gas production; numerical model; optimization; permafrost; simulation https://www.scopus.com/inward/record.uri?eid=2-s2.0-85107815547&doi=10.1016%2fj.energy.2021.121137&partnerID=40&md5=25afa891fa2354a57e36b0725678a722 cited By 11 E. Zhao J. Hou Y. Ji Y. Liu Y. Bai article Martínez-Abarca2021 The responses of lake productivity, vegetation, and fire events in the Basin of Mexico to orbital changes from late MIS 6 to MIS 3 (146–35 ka) have been studied based on geochemical (Ti, TIC, TOC, C/N), charcoal (CHAR) and pollen data of the sediment core CHA08 from Lake Chalco. The paleoenvironmental reconstruction identifies the MIS 6 as a wetter period with episodes of dry conditions, low forest cover and low fire activity. A sudden change from wetter to dry environments with low to high forest cover and fire activity episodes characterized the end of the MIS 6 (132–130 ka) coincident with high spring insolation. Variations in vegetation composition, with a tendency towards higher forest cover, fire-activity, runoff, and organic matter availability, are recorded during the MIS 5, MIS 4, and MIS 3. However, a reduction in the fire-activity was recorded for the cold and dry MIS 4. Spectral analysis based on the titanium concentration record of Lake Chalco suggests a precessional forcing on runoff variations. We explored the impact of the Intertropical Convergence Zone latitudinal migrations which have been related to the summer insolation at 65° N by comparing runoff data with other sedimentary records from North and Central America. Our results highlight the sensitivity of the high altitude tropical basin to climate variations. © 2021 Elsevier Ltd 2021 English 08959811 10.1016/j.jsames.2021.103231 Journal of South American Earth Sciences 109 Elsevier Ltd Instituto de Geología, Universidad Nacional Autónoma de Mexico, Ciudad Universitaria, Ciudad de Mexico, CP 04510, Mexico; Instituto de Geofísica, Universidad Nacional Autónoma de Mexico, Ciudad Universitaria, Ciudad de Mexico, CP 04510, Mexico; Large Lakes Observatory & Dept. of Earth and Environmental Sciences, University of Minnesota Duluth, Duluth, MN 55812, United States; Posgrado en Ciencias Biológicas, Universidad Nacional Autónoma de Mexico, Ciudad Universitaria, Ciudad de Mexico, CP 04510, Mexico environmental change; fire history; glacial-interglacial cycle; paleoenvironment; palynology; reconstruction; vegetation dynamics, Lake Chalco; Mexico [North America] https://www.scopus.com/inward/record.uri?eid=2-s2.0-85102044799&doi=10.1016%2fj.jsames.2021.103231&partnerID=40&md5=c24a118b593709563e6502627abc786f cited By 11 L.R. Martínez-Abarca S. Lozano-García B. Ortega-Guerrero C.M. Chávez-Lara E. Torres-Rodríguez M. Caballero E.T. Brown S. Sosa-Nájera C. Acosta-Noriega V. Sandoval-Ibarra article Deino2021 The Publisher regrets that this article is an accidental duplication of an article that has already been published in, https://doi.org/10.1016/j.palaeo.2019.109519. The duplicate article has therefore been withdrawn. The full Elsevier Policy on Article Withdrawal can be found at https://www.elsevier.com/about/our-business/policies/article-withdrawal. © 2019 Elsevier B.V. Erratum 2021 English 00310182 10.1016/j.palaeo.2019.109535 Palaeogeography, Palaeoclimatology, Palaeoecology 571 Elsevier B.V. https://www.scopus.com/inward/record.uri?eid=2-s2.0-85079753298&doi=10.1016%2fj.palaeo.2019.109535&partnerID=40&md5=dbd3b5e762fdb05ff8899ae256da845a Cited by: 0 Alan L. Deino article Qin2024168 Article 2021 10.12143/j.ztgc.2021.01.003 Drilling Engineering 48 7-14 01 H. Ran J. Liang N. Liang Q. Xue S. Ma article Yanev202145 The described exotic rock block (60×80×13-15 cm) was found at 290 m depth in a lower.middle Badenian gypsum layer in the Koshava mine, NW Bulgaria, near the Danube River. It is greyish-black, granular, with layered structure and layers composed of α-quartz rosettes covered with organic matter (kerogen-like type with high contents of Ge, Mo and B), wood relicts with chalcedony replacement, and porous lenses with compact accumulation of organic matter. The block is coated with quartz crust, up to 2 cm thick, with regmaglypt-like forms, also replaced by quartz. Aside from the surface, melting phenomena were also observed inside the quartz rosettes and especially in the wood relicts and porous lenses. The melted drops are actually crystallized chalcedony. The organic matter accumulations contain Si-organic zoned micrometre-sized spherules. Fe silicides were found in the organic matter of all parts of the block, in which hapkeite was determined by X-ray analysis. Other detected minerals include graphite, cristobalite, coesite, skeletal and framboidal pyrite, moassanite, magnetite, suessite, sphalerite and minerals formed in the gypsum lagoon (gypsum, celestine, barite, calcite, halite and clays). The geological position of the block in the gypsum without any other sediments, the extensive melting phenomena with melted spherules, crushed quartz, its enrichment in 18O isotope and the presence of coesite suggest that it is shock ejecta, in certain aspects resembling the large Muong Nong-type tektites, but its characteristics could be the basis for distinguishing it as a new tektite type. The fact that it was found in a gypsum layer of early.middle Badenian age points to its probable association with the Ries-Steinheim impact event, despite the long distance between them (~1100 km). © 2021 Geological Institute â€Strashimir Dimitrovâ€, Bulgarian Academy of Sciences. 2021 10.52321/GeolBalc.50.1.45 Geologica Balcanica 50 45-65 Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, Sofia, 1113, Bulgaria; University of Stuttgart, Stuttgart, 70569, Germany; Institute of Geology of Ore Deposits, Mineralogy, Petrography and Geochemistry (IGEM), Russian Academy of Sciences, 35/1 Staromonetnyi pereulok, Moscow, 119017, Russian Federation; Bulgarian Geological Society, Bulgaria 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85123594717&doi=10.52321%2fGeolBalc.50.1.45&partnerID=40&md5=0894f71d491415e900af44a7f60ea39b cited By 1 Y. Yanev A. Benderev N. Zotov E. Dubinina I. Iliev S. Georgiev I. Ilieva I. Sergeeva article Tian20211496 The Songliao Basin in NE China is a large rift basin filled with Cretaceous terrestrial sediments. Lacustrine mudstones of the Nenjiang Formation form an important source rock in the Cretaceous Songliao Basin. These shales are commonly thought to have been deposited in deep, quiet, and anoxic environments. Samples obtained from the core of the SK-2 scientific borehole provide critical insights to understand the hydrodynamic and hydroclimatic environments, which are, however, different from the traditional views regarding the deposition of these rocks. By following a mudstone description guide, five different mudstone lithofacies (LF) transported and deposited by muddy hyperpycnal flows and muddy debris flows were recognized. They are laminated fine mudstone (LF1), laminated medium mudstone (LF2), and laminated coarse mudstone (LF3) showing pairs of inverse grading (Ha) and normal grading (Hb) under the microscope, graded coarse mudstone (LF4) and massive coarse mudstone (LF5). We found that mudstones of the First Member of the Nenjiang Formation are dominated by siliciclastic detritus and argillaceous components and show frequent variations in grain size. Because large-scale sub-lacustrine channels travelling long distance (>80 km) were widely distributed in the Songliao palaeolake during the deposition of the Nenjiang Formation, fluctuations in mudstone grain size might have been caused by velocity fluctuations in flows. Sedimentary structures and textures preserved in mudstones of the First Member of the Nenjiang Formation indicate that the majority of these lithofacies were accumulated by muddy hyperpycnal flows and muddy debris flows. Therefore, a depositional model dominantly influenced by muddy hyperpycnal flows and debris flows is proposed. This work not only provides a new view for the depositional process of mudstones of the Songliao Basin, NE China, but also give insights to understand lacustrine palaeoenvironment and terrestrial palaeoclimate. © 2020 John Wiley & Sons Ltd 2021 English 00721050 10.1002/gj.4017 Geological Journal 56 John Wiley and Sons Ltd 1496-1509 State Key Laboratory of Biogeology and Environmental Geology, School of Earth Sciences and Resources, China University of Geosciences (Beijing), Beijing, China; School of Earth Science and Resources, China University of Geosciences (Beijing), Beijing, China; Department of Earth and Atmospheric Sciences, Indiana University, Bloomington, IN, United States; GCS Argentina SRL, Florida 1600, Bahía Blanca, Argentina; Departamento de Geología, Universidad Nacional del Sur, Bahía Blanca, Argentina 3 borehole; Cretaceous; debris flow; gravity flow; hydrocarbon reservoir; lacustrine deposit; lithofacies; mudstone; reservoir characterization; shale; source rock, China; Songliao Basin https://www.scopus.com/inward/record.uri?eid=2-s2.0-85092058396&doi=10.1002%2fgj.4017&partnerID=40&md5=a0752ceade5ab3230ed43d6c0dcf73f6 cited By 2 X. Tian Y. Gao Z. Li Z. Carlos Z. Chen Y. Huang E. Yu C. Wang article godard2021geochemical The transition from the Semail ophiolite mantle to the underlying metamorphic sole was drilled at ICDP OmanDP Hole BT1B. We analyzed the bulk major, volatile and trace element compositions of the mantle-derived listvenite series and metamorphic rocks, with the aim to constrain chemical transfers associated with peridotite carbonation along the ophiolite basal thrust. The listvenite series comprise variously carbonated serpentinites and (fuchsite-bearing) listvenites. They have high CO2 (up to 43 wt.%) and variable H2O (0–12 wt.%). Yet, they have compositions close to that of the basal banded peridotites for most major and lithophile trace elements, with fuchsite-bearing listvenites overlapping in composition with amphibole-bearing basal lherzolites (e.g., Al2O3 = 0.1–2.2 wt.%; Yb = 0.05–1 x CI-chondrite). The protolith of the listvenite series was likely similar in structure and composition to serpentinized banded peridotites which immediately overlie the metamorphic sole elsewhere in Oman. The listvenite series are enriched in fluid mobile elements (FME) compared to Semail peridotites (up to ∼103–104 x Primitive Mantle), with concentrations similar to the underthrusted metabasalts and/or metasediments for Cs, Sr and Ca and sometimes even higher for Pb, Li, As, and Sb (e.g., Li up to 130 μg/g; As up to 170 μg/g). We also observe a decoupling between Sr-Ca enrichments and other FME, indicating interactions with several batches of deep CO2-rich fluids transported along the basal thrust. These results suggest that peridotite carbonation could represent one of the major trap-and-release mechanisms for carbon, water and FME along convergent margins. © 2021. American Geophysical Union. All Rights Reserved. 2021 English 21699313 10.1029/2021JB022733 Journal of Geophysical Research: Solid Earth 126 Wiley Online Library e2021JB022733 Géosciences Montpellier, CNRS, Université de Montpellier, Montpellier, France; Department of Earth and Environmental Sciences, The University of Manchester, Manchester, United Kingdom; Department of Geology, Trinity College Dublin, Dublin, Ireland; School of Earth and Ocean Sciences, Cardiff University, Cardiff, United Kingdom; Academia Sinica, Institute of Earth Science, Taipei, Taiwan; LDEO, Columbia University, Palisades, NY, United States; Department of Earth and Planetary Sciences, Graduate School of Environmental Studies, Nagoya University, Nagoya, Japan; School of Geography, Earth and Environmental Sciences, Plymouth University, Plymouth, United Kingdom; School of Ocean & Earth Science, University of Southampton, Southampton, United Kingdom 12 drilling; metasediment; ophiolite; peridotite; petrogenesis; petrography; serpentinite; serpentinization, Oman https://www.scopus.com/inward/record.uri?eid=2-s2.0-85131386210&doi=10.1029%2f2021JB022733&partnerID=40&md5=905c0708dfe8bda517cc2a0e43f1b5f0 cited By 7 Marguerite Godard EJ Carter T Decrausaz R Lafay E Bennett F Kourim J-C Obeso K Michibayashi M Harris JA Coggon others article nothaft2021geochemical 2021 Journal of Geophysical Research: Biogeosciences 126 Wiley Online Library e2020JG006025 10 Daniel B Nothaft Alexis S Templeton Jeemin H Rhim David T Wang Jabrane Labidi Hannah M Miller Eric S Boyd Juerg M Matter Shuhei Ono Edward D Young others article Holmes2021 Core samples obtained from scientific drilling could provide large volumes of direct mi-crostructural and compositional data, but generating results via the traditional treatment of such data is often time-consuming and inefficient. Unifying microstructural data within a spatially referenced Geographic Information System (GIS) environment provides an opportunity to readily locate, visual-ize, correlate, and apply remote sensing techniques to the data. Using 26 core billet samples from the San Andreas Fault Observatory at Depth (SAFOD), this study developed GIS-based procedures for: 1. Spatially referenced visualization and storage of various microstructural data from core billets; 2. 3D modeling of billets and thin section positions within each billet, which serve as a digital record after irreversible fragmentation of the physical billets; and 3. Vector feature creation and unsuper-vised classification of a multi-generation calcite vein network from cathodluminescence (CL) imagery. Building on existing work which is predominantly limited to the 2D space of single thin sections, our results indicate that a GIS can facilitate spatial treatment of data even at centimeter to nanometer scales, but also revealed challenges involving intensive 3D representations and complex matrix transformations required to create geographically translated forms of the within-billet coordinate systems, which are suggested for consideration in future studies. © 2021 by the authors. Licensee MDPI, Basel, Switzerland. 2021 English 22209964 10.3390/ijgi10050332 ISPRS International Journal of Geo-Information 10 MDPI AG Department of Geography and Geosciences, University of Louisville, Louisville, KY 40208, United States 5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85107208468&doi=10.3390%2fijgi10050332&partnerID=40&md5=69c6d68479ca89fe7c4e7f3e0b60547e cited By 0 E.M. Holmes A.E. Gaughan D.J. Biddle F.R. Stevens J. Hadizadeh article Krueger2021 Eastern Africa has been a prime target for scientific drilling because it is rich in key paleoanthropological sites as well as in paleolakes, containing valuable paleoclimatic information on evolutionary time scales. The Hominin Sites and Paleolakes Drilling Project (HSPDP) explores these paleolakes with the aim of reconstructing environmental conditions around critical episodes of hominin evolution. Identification of biological taxa based on their sedimentary ancient DNA (sedaDNA) traces can contribute to understand past ecological and climatological conditions of the living environment of our ancestors. However, sedaDNA recovery from tropical environments is challenging because high temperatures, UV irradiation, and desiccation result in highly degraded DNA. Consequently, most of the DNA fragments in tropical sediments are too short for PCR amplification. We analyzed sedaDNA in the upper 70 m of the composite sediment core of the HSPDP drill site at Chew Bahir for eukaryotic remnants. We first tested shotgun high throughput sequencing which leads to metagenomes dominated by bacterial DNA of the deep biosphere, while only a small fraction was derived from eukaryotic, and thus probably ancient, DNA. Subsequently, we performed cross-species hybridization capture of sedaDNA to enrich ancient DNA (aDNA) from eukaryotic remnants for paleoenvironmental analysis, using established barcoding genes (cox1 and rbcL for animals and plants, respectively) from 199 species that may have had relatives in the past biosphere at Chew Bahir. Metagenomes yielded after hybridization capture are richer in reads with similarity to cox1 and rbcL in comparison to metagenomes without prior hybridization capture. Taxonomic assignments of the reads from these hybridization capture metagenomes also yielded larger fractions of the eukaryotic domain. For reads assigned to cox1, inferred wet periods were associated with high inferred relative abundances of putative limnic organisms (gastropods, green algae), while inferred dry periods showed increased relative abundances for insects. These findings indicate that cross-species hybridization capture can be an effective approach to enhance the information content of sedaDNA in order to explore biosphere changes associated with past environmental conditions, enabling such analyses even under tropical conditions. © Copyright © 2021 Krueger, Foerster, Trauth, Hofreiter and Tiedemann. Article 2021 English 22966463 10.3389/feart.2021.683010 Frontiers in Earth Science 9 Frontiers Media S.A. Ethiopia; Bacteria (microorganisms); Chlorophyta; Eukaryota; Gastropoda; Hexapoda; archaeological evidence; biosphere; core analysis; DNA; hominid; human settlement; hybridization; irradiation; paleoclimate; paleoecology; paleoenvironment; paleolimnology; reconstruction; timescale; tropical environment; ultraviolet radiation https://www.scopus.com/inward/record.uri?eid=2-s2.0-85116487254&doi=10.3389%2ffeart.2021.683010&partnerID=40&md5=a8b2b7d679113d1a53788ef00bb5b517 Cited by: 2; All Open Access, Gold Open Access, Green Open Access Johanna Krueger Verena Foerster Martin H. Trauth Michael Hofreiter Ralph Tiedemann article giuntoli_protracted_2020 During continental collision, large tracts of crust are mobilized along major shear zones. The metamorphic conditions at which these zones operate, the duration of thrusting, and the deformation processes that facilitated hundreds of km of tectonic transport are still unclear. In the Scandinavian Caledonides, the Lower Seve Nappe displays a main mylonitic foliation with thickness of 1 km. This foliation is overprinted by a brittle-to-ductile deformation pattern localized in C- and C′-type shear bands proximal to the tectonic contact with the underlying Särv Nappe. Thermobarometry of amphibolites and micaschists suggests a first high-pressure stage at 400–500°C and 1–1.3 GPa recorded in mineral relics. The main mylonitic foliation developed under epidote amphibolite facies conditions along the retrograde path from 600°C and 1 GPa to 500°C and 0.5 GPa. Age dating of synkinematic titanite grains in the amphibolites indicates that this mylonitic fabric formed at around 417 ± 9 Ma but older ages spanning 460–430 Ma could represent earlier stages of mylonitization. The shear bands developed at lower metamorphic conditions of 300–400°C and 0.3 GPa. In the micaschists, the recrystallized grain size of quartz decreases toward the shear bands. Monomineralic quartz layers are eventually dismembered to form polyphase aggregates deforming by dominant grain size sensitive creep accompanied by slip in muscovite and chlorite. Plagioclase zoning truncations suggest that the shear bands originated by fracturing followed by ductile deformation. The results suggest protracted and long-lasting shearing under amphibolite to greenschist facies conditions during the juxtaposition, stacking, and exhumation of the Lower Seve Nappe. 2020 en 1944-9194 10.1029/2020TC006267 Tectonics 39 e2020TC006267 9 U-Pb dating, Caledonides, electron backscatter diffraction, deformation mechanisms, petrochronology, thrusting, U-Pb dating https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2020TC006267 \_eprint: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2020TC006267 Francesco Giuntoli Luca Menegon Clare J. Warren James Darling Mark W. Anderson article Cao2020 Shale oil is hosted in nanopores of organic-rich shales, so pore characteristics are significant for shale oil accumulation. Here we analyzed pore characteristics of 39 lacustrine shale samples of the Late Cretaceous Qingshankou Formation (K2qn) in the Songliao Basin, which is one of the main shale oil resource basins in China, using field emission-scanning electron microscopy (FE-SEM), and low-pressure nitrogen adsorption. We accomplished fractal analysis, correlation analysis using correlation matrix and multidimensional scaling (MDS), and prediction of fractal dimensions, which is the first time to predict pore fractal dimensions of shales. Interparticle pores are highly developed in K2qn. These shales have mesoporous nature and slit-shaped pores. Compared with the second and third members (K2qn2,3), the first member of the Qingshankou Formation (K2qn1) has a larger average pore diameter, much smaller surface area, fewer micropores, simpler pore structure and surface indicated by smaller fractal dimensions. In terms of pore characteristics, K2qn1 is better than K2qn2,3 as a shale oil reservoir. When compared with marine Bakken Formation shales, lacustrine shales of the Qingshankou Formation have similar complexity of pore structure, but much rougher pore surface. This research can lead to an improved understanding of the pore system of lacustrine shales. © 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/). 2020 English 19961073 10.3390/en13082027 Energies 13 MDPI AG State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing, 100083, China; School of Earth Sciences and Resources, China University of Geosciences, Beijing, 100083, China; Research Institute of Petroleum Exploration and Development, PetroChina, Beijing, 100083, China; College of Geoscience and Surveying Engineering, China University of Mining and Technology, Beijing, 100083, China; Geological Engineering and Geomatics, Chang'an University, Xi'an, 710054, China 8 Enamels; Field emission microscopes; Fractal dimension; Gas adsorption; Petroleum reservoir engineering; Petroleum reservoirs; Pore structure; Scanning electron microscopy; Shale oil, Correlation analysis; Correlation matrix; Field emission scanning electron microscopy; Fractal analysis; Multi-dimensional scaling; Nitrogen adsorption; Organic-rich shales; Pore characteristics, Nanopores https://www.scopus.com/inward/record.uri?eid=2-s2.0-85084064890&doi=10.3390%2fen13082027&partnerID=40&md5=a60ab599ce4fcb79a573b40b0079f07e cited By 7 X. Cao Y. Gao J. Cui S. Han L. Kang S. Song C. Wang article Stranghoener2020 The potential for the mobilization of Fe from secondary phases within subsurface basaltic rocks of the Hawaii Scientific Drilling Project Phase2 (HSDP2) drill core was investigated to elucidate the possible contribution of volcanic islands to the Fe budget of nearby ocean surface waters. Rock specific parameters governing Fe mobilization, such as Fe redox state, specific surface area (SSA), and connected porosity were determined. A four-step sequential extraction procedure using solutions with increasing strength of the extractants was applied to characterize different states of chemical bonding of Fe in secondary phases of the basaltic rocks, a controlling parameter for its release to oceanic water. The sequential extraction results were then used as a measure for the reactivity of secondary Fe-bearing phases and the mobilizable Fe from these rocks. Basaltic rocks with different degrees of weathering showed elevated Fe(III) contents up to 58% total Fe as Fe(III), compared to 11–18% in fresh basalts. SSAs increased with depth, with maximum values of 70 m2/g observed for hyaloclastites. Both parameters depended mainly on the alteration state of the basalt, which was more strongly affected by the fluid chemistry (freshwater ↔ seawater) than by the age of the rocks. The sequential extractions revealed the presence of highly reactive secondary Fe-bearing phases in submarine rocks exposed to seawater whereas observations for rocks altered in freshwater point to better crystallized phases with lower mobilizable Fe contents. In seawater, aging of secondary Fe-bearing phases was most probably suppressed by the adsorption of silica and multivalent anions. Comparing different types of rock, hyaloclastites and pillow basalts showed the highest mobilizable Fe with up to 19% and 16%, respectively, of the total Fe of the bulk rock. The potential for high amounts of mobilizable Fe from basaltic rocks altered under seawater dominated conditions suggests that the submarine part of volcanic ocean islands represent an underestimated source of Fe supply to ocean surface waters. © 2020 Elsevier Ltd 2020 English 08832927 10.1016/j.apgeochem.2020.104705 Applied Geochemistry 121 Elsevier Ltd Institute of Mineralogy, Leibniz Universität Hannover, Callinstr. 3, Hannover, 30167, Germany; Institute of Soil Science, Leibniz Universität Hannover, Herrenhäuser Str. 2, Hannover, 30419, Germany; Geomicrobiology, Federal Institute for Geosciences and Natural Resources, Stilleweg 2, Hannover, 30655, Germany Basalt; Budget control; Chemical bonds; Core drilling; Extraction; Infill drilling; Positive ions; Seawater; Silica; Submarines; Surface waters; Volcanoes; Weathering, Chemical bondings; Controlling parameters; Scientific drilling; Secondary phasis; Sequential extraction; Sequential extraction procedure; Specific surface area (SSA); Volcanic ocean island, Iron compounds, adsorption; basalt; chemical bonding; mobilization; seawater; sequential extraction; silica; surface water; volcanic island, Hawaii https://www.scopus.com/inward/record.uri?eid=2-s2.0-85089266795&doi=10.1016%2fj.apgeochem.2020.104705&partnerID=40&md5=29128762b3e411d9dcde53f2204f9f15 cited By 1 M. Stranghoener S. Dultz H. Behrens A. Schippers article Noah2020 The construction and reliable application of maturation indices is extremely important in deep Earth exploration, yet predicting levels of maturation on a molecular level, especially at overmature stages, is still a major challenge. Here, we report robust, broad ranging and precise maturity parameters that were developed using a continuous core of thermally overmature lacustrine deposits (Shahezi Fm.) from the deep Songke-2 Well (SK-2), Songliao Basin, China, augmented by shallow cores of lower maturity marine deposits (Posidonia Shale) from the Hils Syncline, Germany. The novel indices presented here are based on the general process of thermally-induced cyclization, aromatization and aliphatic chain cracking of hundreds to thousands of compounds during maturation. The newly developed parameters, with an extremely broad dynamic range extending from catagenesis and into metagenesis (vitrinite reflectances (Ro) range from 0.9% to 2.2%), are based on polycyclic and heterocyclic aromatic compounds measured using Fourier transform-ion cyclotron resonance-mass spectrometry (FT-ICR-MS). The high coefficient of correlations between the new maturity parameters with Ro and Tmax demonstrate their utility for assessing precisely the thermal maturity of overmature shales. © 2020 Elsevier Ltd 2020 English 01466380 10.1016/j.orggeochem.2020.104099 Organic Geochemistry 148 Elsevier Ltd Helmholtz Centre Potsdam GFZ - German Research Centre for Geosciences, Department of Geochemistry, Section 3.2 Organic Geochemistry, Telegrafenberg, Potsdam, Germany; GEOS4 GmbH, D-14552 Michendorf, Germany; College of Geoscience and Surveying Engineering, China University of Mining and Technology, Beijing, China; State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing, China Aromatic compounds; Deposits; Mass spectrometry; Shale, Coefficient of correlation; Fourier transform ion cyclotron resonance mass spectrometry; Heterocyclic aromatic compounds; Lacustrine deposits; Maturity assessments; Maturity parameters; Thermally induced; Vitrinite reflectance, Aromatization, catagenesis; chemical alteration; cracking (chemistry); maturation; molecular analysis; PAH; precision; thermal maturity, China; Germany; Songliao Basin, Posidonia https://www.scopus.com/inward/record.uri?eid=2-s2.0-85089426122&doi=10.1016%2fj.orggeochem.2020.104099&partnerID=40&md5=ed4f1bc7a94feaa2da2d84f94db2b90a cited By 8 M. Noah B. Horsfield S. Han C. Wang article Pittarello20201082 Shocked quartz and feldspar grains commonly exhibit planar microstructures, such as planar fractures, planar deformation features, and possibly microtwins, which are considered to have formed by shock metamorphism. Their orientation and frequency are typically reported to be randomly distributed across a sample. The goal of this study is to investigate whether such microstructures are completely random within a given sample, or whether their orientation might also retain information on the direction of the local shock wave propagation. For this work, we selected samples of shatter cones, which were cut normal to the striated surface and the striation direction, from three impact structures (Keurusselkä, Finland, and Charlevoix and Manicouagan, Canada). These samples show different stages of pre-impact tectonic deformation. Additionally, we investigated several shocked granite samples, selected at different depths along the drill core recovered during the joint IODP-ICDP Chicxulub Expedition 364 (Mexico). In this case, thin sections were cut along two orthogonal directions, one parallel and one normal to the drill core axis. All the results refer to optical microscopy and universal-stage analyses performed on petrographic thin sections. Our results show that such shock-related microstructures do have a preferred orientation, but also that relating their orientation with the possible shock wave propagation is quite challenging and potentially impossible. This is largely due to the lack of dedicated experiments to provide a key to interpret the observed preferred orientation and to the lack of information on postimpact orientation modifications, especially in the case of the drill core samples. © 2020 The Authors. Meteoritics & Planetary Science published by Wiley Periodicals LLC on behalf of The Meteoritical Society (MET) 2020 10.1111/maps.13490 Meteoritics and Planetary Science 55 1082-1092 Natural History Museum Vienna, Burgring 7, Vienna, A-1010, Austria; Department of Lithospheric Research, University of Vienna, Althanstrasse 14, Vienna, A-1090, Austria; Department of Earth Sciences, University of Western Ontario, 1151 Richmond Street, London, ON N6A 5B7, Canada; Institute for Earth and Space Exploration, University of Western Ontario, 1151 Richmond Street, London, ON N6A 3K7, Canada 5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85085878809&doi=10.1111%2fmaps.13490&partnerID=40&md5=6fe7d790144d911c5696a5e4d3c36f86 cited By 7 L. Pittarello L. Ferrière J.-G. Feignon G.R. Osinski C. Koeberl article Kring2020 The ~180-km-diameter Chicxulub peak-ring crater and ~240-km multiring basin, produced by the impact that terminated the Cretaceous, is the largest remaining intact impact basin on Earth. International Ocean Discovery Program (IODP) and International Continental Scientific Drilling Program (ICDP) Expedition 364 drilled to a depth of 1335 m below the sea floor into the peak ring, providing a unique opportunity to study the thermal and chemical modification of Earth's crust caused by the impact. The recovered core shows the crater hosted a spatially extensive hydrothermal system that chemically and mineralogically modified ~1.4 × 105 km3 of Earth's crust, a volume more than nine times that of the Yellowstone Caldera system. Initially, high temperatures of 300° to 400°C and an independent geomagnetic polarity clock indicate the hydrothermal system was long lived, in excess of 106 years. © 2020 American Association for the Advancement of Science. All rights reserved. 2020 10.1126/sciadv.aaz3053 Science Advances 6 Universities Space Research Association, Lunar and Planetary Institute, 3600 Bay Area Boulevard, Houston, TX 77058, United States; Department of Earth and Planetary Sciences, Rutgers University New Brunswick, Piscataway Township, NJ 08854, United States; Institut fur Geologie, Universitat Hamburg, Bundesstrase 55, Hamburg, 20146, Germany; Departamento de Recursos Del Mar, CINVESTAV-MERIDA, Carret. Merida-Progreso, S/N, Merida, Yucatan, 97215, Mexico; Institute for Earth and Space Exploration and Department of Earth Sciences, University of Western Ontario, London, ON N6A 5B7, Canada; Institut Pour la Recherche et le Developpement, Aix Marseille Universite, CNRS, Coll France, INRA, Cerege, Aix-en-Provence, France; Eyring Materials Center, Arizona State University, Tempe, AZ 85287-8301, United States; Centre for Astrobiology, School of Physics and Astronomy, University of Edinburgh, Edinburgh, EH9 3FD, United Kingdom; WA-Organic and Isotope Geochemistry Centre (WA-OIGC), School of Earth and Planetary Sciences, Curtin University, Bentley, WA 6102, Australia; Institute for Geophysics, Jackson School of Geosciences, University of Texas at Austin, Austin, TX 78758-4445, United States; Department of Earth Science and Engineering, Imperial College London, London, SW7 2AZ, United Kingdom; Department of Geosciences, Pennsylvania State UniversityPA 16802, United States; GeoRessources, Universite de Lorraine, Cnrs, Vandoeuvre-les-Nancy, 54 500, France; Analytical, Environmental and Geo-Chemistry, Vrije Universiteit Brussel, Pleinlaan 2, Brussels, 1050, Belgium; Natural History Museum, Burgring 7, Vienna, 1010, Austria; Alfred Wegener Institute Helmholtz Centre of Polar and Marine Research, Bremerhaven, 27568, Germany; Department of Earth and Planetary Science, University of Tokyo, Hongo 7-3-1, Tokyo, 113-0033, Japan; British Geological Survey, Edinburgh, United Kingdom; Geosciences Montpellier, Universite de Montpellier, Montpellier Cedex 05, 34095, France; Groupe de Physico-Chimie de l'Atmosphere, L'Institut de Chimie et Procedes Pour l'Energie, L'Environnement et la Sante (ICPEES), Umr 7515 Universite de Strasbourg-CNRS, 1 rue Blessig, Strasbourg, 67000, France; Instituto de Geofisica, Universidad Nacional Autonoma de Mexico, Cd. Universitaria, Coyoacan, Ciudad de Mexico, C. P. 04510, Mexico; School of Geographical and Earth Sciences, University of Glasgow, Gregory, Lilybank Gardens, Glasgow, G12 8QQ, United Kingdom; University of Freiburg, Geology, Albertstrase 23b, Freiburg, 79104, Germany; Department of Geology and Geophysics, University of Utah, 115 S 1460 E (FASB), Salt Lake City, UT 84112, United States; Ocean Resources Research Center for Next Generation, Chiba Institute of Technology, 2-17-1, Tsudanuma, Narashino-city, Chiba275-0016, Japan; Faculty of Earth and Life Sciences (FALW), Vrije Universiteit Amsterdam, de Boelelaan 1085, Amsterdam, 1018HV, Netherlands; Kochi Institute for Core Sample Research, Japan Agency for Marine-Earth Science and Technology, 200 Monobe Otsu, Nankoku, Kochi, 783-8502, Japan; Department of Geosciences, University of Alaska Fairbanks, 1930 Yukon Drive, Fairbanks, AK 99775, United States; Planetary Science Institute, School of Earth Sciences, China University of Geosciences (Wuhan), 388 Lumo Rd. Hongshan Dist., Wuhan, China; Department of Chemistry, Toho University, Funabashi, Chiba, 274-8510, Japan 22 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85086355179&doi=10.1126%2fsciadv.aaz3053&partnerID=40&md5=ec98d66c05f8bd266193849788c99e8f cited By 49 D.A. Kring S.M. Tikoo M. Schmieder U. Riller M. Rebolledo-Vieyra S.L. Simpson G.R. Osinski J. Gattacceca A. Wittmann C.M. Verhagen C.S. Cockell M.J.L. Coolen F.J. Longstaffe S.P.S. Gulick J.V. Morgan T.J. Bralower E. Chenot G.L. Christeson P. Claeys L. Ferrière C. Gebhardt K. Goto S.L. Green H. Jones J. Lofi C.M. Lowery R. Ocampo-Torres L. Pérez-Cruz A.E. Pickersgill M.H. Poelchau A.S.P. Rae C. Rasmussen H. Sato J. Smit N. Tomioka J. Urrutia-Fucugauchi M.T. Whalen L. Xiao K.E. Yamaguchi article Lü2020153 Article 2020 10.31035/cg2020001 China Geology 3 153 – 172 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85107635137&doi=10.31035%2fcg2020001&partnerID=40&md5=e6353c8c8dd8b3e34de0f99f0ecb250d Cited by: 4; All Open Access, Gold Open Access Qing-tian Lü Jia-yong Yan Xuan-hua Chen He-Sheng Hou Wen-shi Wang Yu-le Hu article Süer20201655 This study presents the results of a real-time gas monitoring experiment conducted, via the use of a quadrupole mass spectrometer, in a mofette field within the Tekke Hamam geothermal site in western Anatolia (Turkey), a tectonically active region hosting several east–west trending grabens. The study is aimed to establish a baseline gas profile of the region. Within the framework of the experiment, gas compositions (CO2, N2, O2, H2, H2S, CH4, He, and Ar) and flow rate of a mofette were monitored during two observation periods: November 2007–January 2008 and April–July 2008. During the course of monitoring, the major gas component was CO2 with concentration changing around 96 volume percent. Other gases, from the most abundant to the least, were N2, CH4, O2, H2S, Ar, H2, and He. The study produced a short-term, baseline gas profile of the region with daily/diurnal variations and temporal gas fluctuations appearing as instant signals. Although the temporal gas fluctuations did not reach the anomaly level (variations staying within the mean ± 2σ), some of the variations in more than one parameter in the gas compositions (exceeding the mean ± 1σ), accompanied by changes in the diurnal gas pulses lasting for long durations, were correlated with the seismic events selected according to the adopted seismic event elimination criteria. The variations were mainly attributed to changing gas mixing ratios in relation to porosity/permeability modifications possibly related to seismicity. Studies involving the continuous monitoring of meteorological parameters are necessary to assign these variations to geogenic events. © 2020, Springer Nature B.V. 2020 English 0921030X 10.1007/s11069-020-04238-8 Natural Hazards 104 Springer Science and Business Media B.V. 1655-1678 Department of Geological Engineering, Middle East Technical University, Ankara, 06800, Turkey; Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences, Potsdam, 14473, Germany; Department of Petroleum and Natural Gas Engineering, Middle East Technical University, Ankara, 06800, Turkey; Central Laboratory, Middle East Technical University, Ankara, 06800, Turkey 2 concentration (composition); environmental monitoring; gas flow; geothermal system; mass spectrometry; mixing ratio; real time; seismic method; seismicity, Anatolia; Turkey https://www.scopus.com/inward/record.uri?eid=2-s2.0-85089975052&doi=10.1007%2fs11069-020-04238-8&partnerID=40&md5=a29a0227c331214b61fd1059a1fcf1fb cited By 1 S. Süer T. Wiersberg N. Güleç J. Erzinger M. Parlaktuna article Pan2020 Numerous models have been developed for prediction of gas hydrate saturation based on the microstructural relationship between gas hydrates and sediment grains. However, quantification of hydrate saturation and morphology from elastic properties has been hindered by failing to account for complex hydrate distributions. Here, we develop a generalized effective medium model by applying the modified Hashin-Shtrikman bounds to a newly developed cementation theory. This model is validated by experimental data for synthetic methane and tetrahydrofuran hydrates. Good comparison of model predictions with experimental measurements not only reveals its ability to merge the results of contact cementation theory and effective medium theory, but also indicates its feasibility for characterizing complex morphologies. Moreover, the results of inverting acoustic measurements quantitatively confirm that for synthetic samples in “excess-gas” condition gas hydrates mainly occur as a hybrid-cementing morphology with a low percentage of pore-filling morphology, whereas for pressure-core hydrate-bearing sediments in natural environments they exist as matrix-supporting and pore-filling morphologies with a very low percentage of hybrid-cementing morphology. The hydrate saturations estimated from sonic and density logs in several regions including northern Cascadia margin (Integrated Ocean Drilling Program Expedition 311, Hole U1326D and Hole U1327E), Alaska North Slope (Mount Elbert test well) and Mackenzie Delta (Mallik 5L-38), are comparable to the referenced hydrate saturations derived from core data and resistivity, and/or nuclear magnetic resonance log data, confirming validity and applicability of our model. Furthermore, our results indicate that ~8% hybrid-cementing, ~33% matrix-supporting and ~59% pore-filling hydrates may coexist in the fine-grained and clay-rich marine sediments on the northern Cascadia margin, whereas ~10% hybrid-cementing, ~54% matrix-supporting and ~36% pore-filling hydrates may coexist in the coarse-grained and sand-dominated terrestrial sediments of the Alaska North Slope and Mackenzie Delta. © 2019 The Authors 2020 English 02648172 10.1016/j.marpetgeo.2019.104166 Marine and Petroleum Geology 113 Elsevier Ltd Department of Geophysical Technology, Research Institute of Petroleum Exploration and Development, Beijing, 100083, China; Seismic Anisotropy Group, Department of Geosciences, The University of Tulsa, Tulsa, 74104, United States; GEOMAR, Helmhotz Center for Ocean Research, Kiel, Germany; Geotek Ltd., 4 Sopwith Way, Daventry, NN11 8PB, United Kingdom Cementing (shafts); Elastic waves; Filling; Gases; Hydration; Matrix algebra; Morphology; Nuclear magnetic logging; Radioactivity logging; Sediments; Software testing; Submarine geology, Effective medium model; Effective medium theories; Elastic wave velocity; Hydrate bearing sediments; Hydrate saturation; Integrated ocean drilling programs; Modified cementation theory; Nuclear magnetic resonance logs, Gas hydrates, cementation; elastic wave; gas hydrate; marine sediment; model validation; quantitative analysis; saturation; wave velocity, Alaska; Alaska Peninsula; Canada; Cascadia Margin; Mackenzie Delta; Northwest Territories; Pacific Ocean; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-85076492717&doi=10.1016%2fj.marpetgeo.2019.104166&partnerID=40&md5=89b94e6d2b49d822671142a58fb99081 cited By 10 H. Pan H. Li J. Chen M. Riedel M. Holland Y. Zhang S. Cai article Weber20201453 Article 2020 10.1017/RDC.2020.28 Radiocarbon 62 1453 – 1473 5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85095988340&doi=10.1017%2fRDC.2020.28&partnerID=40&md5=394068751f112624ae21c870df24d8d1 Cited by: 1 Nurit Weber Boaz Lazar Ofra Stern George Burr Ittai Gavrieli Mark Roberts Mark D Kurz Yoseph Yechieli Mordechai Stein article Yang2020 Cretaceous terrestrial sedimentary records are crucial for our understanding of geological systems’ responses to past climate change under greenhouse condition. Numerous publications have documented that Milankovitch cycles were a dominant climate driver over multi-millennial timescales. However, most of these orbital signals were derived from marine records obtained during the Cenozoic geological period, whereas knowledge of Milankovitch cycles preserved in lacustrine sediments prior to the Cenozoic is limited due to the lack of a precise chronological framework, poor preservation rate of terrestrial sediments, limited records, and fewer experts in this research area. This paper reports high-resolution X-ray fluorescence (XRF) elemental records of K, Ti, Rb, Sr, Zr, Zr/Rb, Rb/Sr, and K/Ti from Member 1 (k2n1) and Member 2 (k2n2) of the Nenjiang Formation, which were obtained from a near-continuous SK-2 East (SK-2e) borehole drilled in the Songliao Basin (SB) of northeastern (NE) China. Variations of the elemental records reveal a humid-arid-humid-semiarid climatic evolution throughout the deposition of k2n1 and a humid-arid-humid-arid climatic variation throughout the deposition of k2n2. In this context, K2n1 experienced a relatively longer humid period and more pronounced climatic fluctuation than K2n2. A method of average spectral misfit (ASM) was adopted to successfully identify two optimal sedimentation rates of 6.577 and 8.369 cm/ka for K2n1 and K2n2, respectively. Based on these two sedimentation rates, nearly all significant Milankovitch cycles preserved in the Rb/Sr record were recognized. It is suggested that westerly wind was the main climatic driving factor of climate evolution in the SB under the forcing of Milankovitch cycles. The collectively regulation of obliquity and precession increased the seasonal contrasts during humid periods in the Nenjiang Formation and thereby amplified the paleomonsoon effect, thus bringing more moisture towards the SB and lead to enhanced rainfall. © 2019 Elsevier Ltd 2020 English 13679120 10.1016/j.jseaes.2019.104183 Journal of Asian Earth Sciences 194 Elsevier Ltd Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, China; University of Chinese Academy of Sciences, Beijing, 100049, China; State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing, 100083, China; School of the Earth Sciences and Resources, China University of Geosciences, Beijing, 100083, China; Department of Computer Science, University of Idaho, Moscow, ID 83843, United States arid environment; climate variation; Cretaceous; deposition; humid environment; lacustrine deposit; Milankovitch cycle; paleoclimate; X-ray fluorescence, China; Songliao Basin https://www.scopus.com/inward/record.uri?eid=2-s2.0-85076516855&doi=10.1016%2fj.jseaes.2019.104183&partnerID=40&md5=e7b55cec9053cbcb56c0fb36db0856c6 cited By 14 H. Yang Y. Huang C. Ma Z. Zhang C. Wang article Dietze2020799 Landscapes in high northern latitudes are assumed to be highly sensitive to future global change, but the rates and long-term trajectories of changes are rather uncertain. In the boreal zone, fires are an important factor in climate-vegetation interactions and biogeochemical cycles. Fire regimes are characterized by small, frequent, lowintensity fires within summergreen boreal forests dominated by larch, whereas evergreen boreal forests dominated by spruce and pine burn large areas less frequently but at higher intensities. Here, we explore the potential of the monosaccharide anhydrides (MA) levoglucosan, mannosan and galactosan to serve as proxies of low-intensity biomass burning in glacial-to-interglacial lake sediments from the high northern latitudes. We use sediments from Lake El'gygytgyn (cores PG 1351 and ICDP 5011-1), located in the far northeast of Russia, and study glacial and interglacial samples of the last 430 kyr (marine isotope stages 5e, 6, 7e, 8, 11c and 12) that had different climate and biome configurations. Combined with pollen and non-pollen palynomorph records from the same samples, we assess how far the modern relationships between fire, climate and vegetation persisted during the past, on orbital to centennial timescales. We find that MAs attached to particulates were well-preserved in up to 430 kyr old sediments with higher influxes from low-intensity biomass burning in interglacials compared to glacials. MA influxes significantly increase when summergreen boreal forest spreads closer to the lake, whereas they decrease when tundra-steppe environments and, especially, Sphagnum peatlands spread. This suggests that lowtemperature fires are a typical characteristic of Siberian larch forests also on long timescales. The results also suggest that low-intensity fires would be reduced by vegetation shifts towards very dry environments due to reduced biomass availability, as well as by shifts towards peatlands, which limits fuel dryness. In addition, we observed very low MA ratios, which we interpret as high contributions of galactosan and mannosan from biomass sources other than those currently monitored, such as the moss-lichen mats in the understorey of the summergreen boreal forest. Overall, sedimentary MAs can provide a powerful proxy for fire regime reconstructions and extend our knowledge of long-term natural fire-climate-vegetation feedbacks in the high northern latitudes. © Author(s) 2020. 2020 English 18149324 10.5194/cp-16-799-2020 Climate of the Past 16 Copernicus GmbH 799-818 Polar Terrestrial Environmental Systems, Alfred Wegener Institute for Polar and Marine Research, Research Unit Potsdam, Potsdam, Telegrafenberg, 14473, Germany; GFZ German Research Centre for Geosciences, Helmholtz Centre Potsdam, Organic Geochemistry, Potsdam, Telegrafenberg, 14473, Germany; Institute of Geology and Petroleum Technologies, Kazan Federal University, Kremlyovskaya Street 4/5, Kazan, 420008, Russian Federation; Department of Marine Microbiology and Biogeochemistry, Royal Netherlands Institute for Sea Research (NIOZ), Utrecht University, Texel, Netherlands; GFZ, German Research Centre for Geosciences, Helmholtz Centre Potsdam, Geomorphology, Surface Organic Geochemistry Lab, Potsdam, Telegrafenberg, 14473, Germany; University of Cologne, Institute of Geology and Mineralogy, Zülpicher Str. 49a, Cologne, 50674, Germany; Institute of Environmental Sciences and Geography, University of Potsdam, Karl-Liebknecht-Str. 24-25, Potsdam, 14476, Germany; Institute of Biochemistry and Biology, University of Potsdam, Karl-Liebknecht-Str. 24-25, Potsdam, 14476, Germany 2 biomass burning; boreal forest; Boreal Kingdom; climate feedback; evergreen forest; fire; global change; interglacial; lacustrine deposit; late glacial; long-term change; low temperature; monosaccharide; paleoclimate; proxy climate record; reconstruction; vegetation history, Chukchi; Elgygytgyn Lake; Russian Federation; Russian Federation; Siberia, Bryophyta; Larix; Picea; Sphagnum https://www.scopus.com/inward/record.uri?eid=2-s2.0-85084609944&doi=10.5194%2fcp-16-799-2020&partnerID=40&md5=036b51e1b3223a01a53e4b1f98468399 cited By 10 E. Dietze K. Mangelsdorf A. Andreev C. Karger L.T. Schreuder E.C. Hopmans O. Rach D. Sachse V. Wennrich U. Herzschuh article Meyer2020 Grain-size analysis and end-member modeling of the clastic fraction of the 25-kyr sediment sequence from Lake Chala, a meromictic crater lake on the lower east slope of Mt. Kilimanjaro, reveal crucial aspects of climate-driven environmental change in equatorial East Africa since the Last Glacial Maximum. The finely laminated sediments of Lake Chala contain only up to 40% of clastic components, the rest are mainly diatom frustules and amorphous organic matter. Measured grain-size distributions were split into six statistically meaningful end members, of which four could be linked to a distinct source and transport mechanism of clastic mineral input: fine aeolian dust from distal sources (EM1), fine catchment runoff (EM2), coarser aeolian dust from proximal sources (EM5) and coarse erosive material from the upper crater slopes (EM6). The two other end members (EM3 and EM4) represented frustules of the two most common diatom taxa in Lake Chala, Afrocymbella barkeri and Nitzschia fabiennejansseniana, which had (partly) survived sample pre-treatment. Temporal variation in normalized abundance of the two dust-derived end members are valuable proxies for past changes in monsoon circulation over equatorial East Africa. During Northern Hemisphere cold periods (e.g., Last Glacial Maximum and Younger Dryas) the Inter-Tropical Convergence Zone shifted southward, enhancing northeasterly monsoon winds in the Lake Chala area and increasing advection of fine dust from the dry Horn of Africa region. Simultaneously, more modest continental heating reduced the prevalence of small-scale atmospheric turbulence, and thus the occurrence of dust devils, resulting in reduced influx of coarse dust from drylands nearby. Conversely, abrupt intensification of the southeasterly monsoon at the onset of the Holocene is recorded by an abrupt increase in the amount of coarse dust delivered to Lake Chala. Temporal variation in the end members representing catchment run-off (EM2) and erosion (EM6) mainly reflect changes in lacustrine sedimentation dynamics associated with major lake-level fluctuation, as evidenced by other paleoenvironmental proxies. Overall this study shows that subdivision of the clastic fraction of lacustrine sediments into statistically robust grain-size end members can provide multiple independent and quantitative proxies which help constrain reconstructions of a region's multi-faceted climate history. © 2020 The Authors Article 2020 English 02773791 10.1016/j.quascirev.2020.106574 Quaternary Science Reviews 247 Elsevier Ltd Bourgogne-Franche-Comte; France; Horn of Africa; Jura [Bourgogne-Franche-Comte]; Kilimanjaro [Kilimanjaro (RGA)]; Kilimanjaro [Tanzania]; Lake Chalain; Tanzania; Bacillariophyta; Nitzschia; Atmospheric thermodynamics; Atmospheric turbulence; Catchments; Climate change; Dust; Glacial geology; Grain size and shape; Lakes; Runoff; Size distribution; Amorphous organic matters; Grain size distribution; Intertropical convergence zone; Lacustrine sedimentations; Lacustrine sediments; Lake level fluctuations; Northern Hemispheres; Small-scale atmospheric turbulence; crater lake; diatom; environmental change; eolian deposit; grain size; lacustrine deposit; Last Glacial Maximum; paleoenvironment; proxy climate record; sedimentation; Sediments https://www.scopus.com/inward/record.uri?eid=2-s2.0-85090738058&doi=10.1016%2fj.quascirev.2020.106574&partnerID=40&md5=0d31a2c9e470b8dee6ca5ed473ee06f8 Cited by: 9; All Open Access, Green Open Access, Hybrid Gold Open Access Inka Meyer Maarten Van Daele Niels Tanghe Marc De Batist Dirk Verschuren techreport greenwood2020reflection 2020 Copernicus Meetings Andrew Greenwood Ludovic Baron Yu Liu György Hetényi Klaus Holliger Mattia Pistone Alberto Zanetti Luca Ziberna Othmar Müntener article jackson2020petrograpic 2020 10.33112/surtsey.14.4 Surtsey Res 14 47--62 Marie D Jackson article Heap2020 The physical properties and mechanical behaviour of impactites are an important parameter in fluid flow models and slope stability and landscape evolution assessments for heavily impacted planetary bodies. We first present porosity, permeability, Young's modulus, and uniaxial compressive strength measurements for three suevites from the Ries impact crater (Germany). Porosity ranges from 0.18 to 0.43, permeability from 5.8 × 10− 16 to 5.1 × 10− 14 m2, Young's modulus from 1.4 to 8.1 GPa, and uniaxial compressive strength from 7.3 to 48.6 MPa. To explore their mechanical behaviour, we performed triaxial deformation experiments on these samples at a range of confining pressures. The brittle–ductile transition for the lowest (0.25) and highest (0.38) porosity suevite samples was at a confining pressure of ~30 and ~10 MPa, respectively (corresponding to, for example, depths of ~1 and ~4 km on Mars, respectively). Microstructural observations show that the dominant deformation micromechanism during brittle deformation is microcracking, and during ductile deformation is distributed cataclastic pore collapse. We show that a theoretically grounded permeability model for welded granular media accurately captures the permeability of the studied suevites, and we use micromechanical models to glean insight as to their mechanical behaviour. Finally, we upscale our laboratory measurements to provide physical property values for length scales more relevant for large-scale models, and we compare these data with those for basalt (a lithology representative of the surface of the inner Solar System bodies). These analyses show how macroscopic fractures serve to increase the permeability and decrease the strength and Young's modulus of suevite and basalt. We also find, for example, that basalt can be a factor of 2–5 stronger than suevite in the shallow crust. Our study suggests, therefore, that the rock masses comprising older, bombarded crusts are substantially weaker and more porous and permeable than the younger plains material on these bodies. These findings should be considered in large-scale fluid flow modelling and when providing crustal strength estimates or slope stability assessments for planetary bodies on which protracted records of impact bombardment are preserved. © 2020 Elsevier Inc. 2020 10.1016/j.icarus.2020.113873 Icarus 349 Géophysique Expérimentale, Institut de Physique de Globe de Strasbourg (UMR 7516 CNRSUniversité de Strasbourg/EOST), 5 rue René Descartes, Strasbourg cedex, 67084, France; Lehrstuhl für Ingenieurgeologie, Technische Universität München, Munich, Germany; Department of Marine, Earth, and Atmospheric Sciences, North Carolina State University, Raleigh, NC, United States; Department of Earth Sciences, Science Labs, Durham University, Durham, DH1 3LE, United Kingdom https://www.scopus.com/inward/record.uri?eid=2-s2.0-85085599886&doi=10.1016%2fj.icarus.2020.113873&partnerID=40&md5=d1c6d7d3cb6c9e3b002692c1a832b571 cited By 3 M.J. Heap H.A. Gilg P.K. Byrne F.B. Wadsworth T. Reuschlé article malvoisin2020measurement 2020 Journal of Geophysical Research: Solid Earth 125 Wiley Online Library e2019JB018877 5 Benjamin Malvoisin Chang Zhang Othmar Müntener Lukas P Baumgartner Peter B Kelemen Oman Drilling Project Science Party article Oliveira2020 The oldest known evidence of large impacts in Early Earth history are Archaean to Palaeoproterozoic impact spherule layers of the Barberton Greenstone Belt in South Africa and the Pilbara craton in Western Australia. Four drill core sections (BH5901, BH5907, BH5911 and BH5949) containing spherule layers were intersected in exploration drilling at Fairview Gold Mine in the northern Barberton Greenstone Belt. Here, we provide a first detailed mineralogical study of these new spherule layer intersections. The spherule layers are densely packed with sand-sized, spherical to ovoid, i.e., in part strongly deformed, “beads”. They generally have morphological and textural features similar to other 3.4–3.2 Ga old spherule layers of the Barberton Greenstone Belt. The Fairview spherule layers are stratigraphically positioned at the contact between the silicified volcanic tuff of the uppermost unit of the Onverwacht Group and the lowermost siliciclastic rocks of the Fig Tree Group, like the S2 and S4 layers in the southern, and S3 layer in the northern, domain of the greenstone belt. Micro-XRF scanning allowed (i) to distinguish spherule layers from their host rocks by their major element distribution, and (ii) to characterize secondary alteration and micro-deformation features in the SL and host rocks. Ni–Cr spinel, the only primary mineral in evidence in these sections, is not distributed uniformly along a spherule layer intersection, and occurrences can not be stratigraphically correlated between the four layer intersections either. Spinel crystals vary with respect to Ni, Cr, Fe and Zn contents and respective zonation patterns for these elements. Zinc abundances are likely related to post-depositional hydrothermal overprint. The results of this investigation comprising geological, petrographic, semiquantitative micro-X-ray fluorescence spectrometry, and quantitative electron microprobe analysis on spinel support a complex and heterogeneous genetic process that must have taken place during spherule formation in an impact vapor plume and in post-depositional times. The Fairview spherule layers are thought to possibly represent the product of a single impact event. They represent fallout into deep-water conditions, as they lack evidence for reworking or sorting by current or wave action. The heterogeneous Ni–Cr spinel concentrations are similar to what has been reported for spinel occurrences in the S3 layer, but considering the complex tectonic overprint on this lithostratigraphic sequence at the changeover from the Onverwacht to the Fig Tree Group it is not possible to conclude whether or not these spherule layers represent the same impact event. © 2019 Elsevier Ltd Article 2020 English 1464343X 10.1016/j.jafrearsci.2019.103718 Journal of African Earth Sciences 162 Elsevier Ltd Australia; Barberton Greenstone Belt; Pilbara Block; Western Australia; Ficus (angiosperm); Archean; host rock; lithostratigraphy; mineralogy; petrography; Proterozoic; siliciclastic deposit; spinel; tuff; X-ray fluorescence https://www.scopus.com/inward/record.uri?eid=2-s2.0-85076193591&doi=10.1016%2fj.jafrearsci.2019.103718&partnerID=40&md5=b2352f6036f944e61e52e791182b23b6 Cited by: 2 Grace Juliana Gonçalves de Oliveira Wolf Uwe Reimold Alvaro Penteado Crósta Natalia Hauser Tanja Mohr-Westheide Roald Tagle Douglas Galante Felix Kaufmann article Prader2020 Pollen of middle Oligocene to early Miocene age from core sediments from the New Jersey Shallow Shelf (Atlantic Coastal Plain: IODP-Expedition 313, Site M0027A), was analyzed using light- and scanning electron microscopy, and a pollen-based bioclimatic analysis was performed. The microflora is dominated by Quercus pollen. Pollen ornamentations indicate that Quercus pollen most likely originated from species of sections Quercus, Lobatae, Quercus/Lobatae and aff. section Protobalanus. Eotrigonobalanus, an extinct Fagaceae lineage, was present in the coastal plain. Relative abundances of several tree taxa (e.g., Carya) did not change significantly between the Oligocene warm phases, but contrast to late middle Miocene (comprising most of the Langhian and Serravallian) records from the same area. By assigning terrestrial palynomorphs to paleovegetation units, topographic movements of these units were identified. The mesophytic forest was the most widespread and zonal vegetation type in the hinterland through the analyzed interval. Periodic changes in the relative abundances of paleovegetation units suggest altitudinal vegetation movements responding to global climate change. Observed movement signals are generally weak, but increases in bisaccate pollen, representing spread of high- and mid-latitude forest, probably reflect the onset of cold intervals such as cooling phases at ~ 29.1, ~ 28.5, and 23.5 Ma. Spread of edaphically controlled forest formations during regression phases also indicates climate change. The onset of the Mi-1 event at ~ 23.03 Ma is probably reflected by a decrease in pollen-inferred paleotemperatures, although the event itself occurred during a sedimentation hiatus. Pollen-based paleoclimate reconstructions indicate long-term stability in temperature and precipitation within the humid warm temperate zone. © 2020 Elsevier B.V. 2020 English 00346667 10.1016/j.revpalbo.2020.104224 Review of Palaeobotany and Palynology 279 Elsevier B.V. Center for Natural History, Hamburg University, Bundesstraße 55, Hamburg, D-20146, Germany; Institute of Geology, University of Hamburg, Bundesstraße 55, Hamburg, D-20146, Germany; Department of Biology, Brandon University, 270 18th Street, Brandon, Manitoba R7A 6A9, Canada; Department of Earth Sciences, Brock University, 1812 Sir Isaac Brock Way, St. Catharines, Ontario L2S 3A1, Canada; Center for Earth System Research and Sustainability, Hamburg University, Bundesstraße 55, Hamburg, D-20146, Germany; Palaeoecology, Department of Physical Geography, Heidelberglaan 2, Utrecht, 3584 CS, Netherlands climate variation; deciduous tree; dominance; fossil record; Miocene; Neogene; Oligocene; paleobotany; Paleogene; paleotemperature; palynomorph; pollen; relative abundance; sediment core; topography, New Jersey; North America; United States, Carya; Fagaceae; Quercus https://www.scopus.com/inward/record.uri?eid=2-s2.0-85083504676&doi=10.1016%2fj.revpalbo.2020.104224&partnerID=40&md5=fc1200aa83b33bf79632a69037d1d616 cited By 6 S. Prader U. Kotthoff D.R. Greenwood F.M.G. McCarthy G. Schmiedl T.H. Donders article Goldstein2020 The Dead Sea Deep Drilling Project drilled 456 meters into the deepest floor of the Dead Sea and recovered a record of the past ∼220 kyr of the Levant hydroclimate history, that is, Marine Isotope Stages 1–7, including the last three interglacials and the last two glacials. We present an updated chronology of the core from DSDDP Hole 5017-1-A, from the Dead Sea's deepest basin, that refines our previous chronology (Torfstein et al. 2015) based on new information. The updated chronology uses the following approaches: (1) radiocarbon ages of Kitagawa et al. (2017); (2) correlation of specific layers in the core with U–Th-dated sediments on the Dead Sea margin, particularly during the interval of glacial Lake Lisan (MIS 2,3,4); (3) tuning of the δ18O data of DSDDP core aragonite to the U–Th dated oxygen isotopes of regional cave speleothems; and (4) tuning of the DSDDP aragonite δ18O data to summer insolation curves when the cave δ18O chronology is less clear. The updated chronology reveals a strong relationship between the sedimentary facies comprising the core and Northern Hemisphere summer insolation variations. It shows that sequences of sediments marking drier/wetter/drier climate conditions in the lake's watershed (e.g., salt/muds/salt, respectively) appear across the flank/peak/flank segments of several summer insolation peaks. In particular, the transition from drier to wetter sedimentary facies during mid-latitude insolation peaks coincides with the intervals of sapropel conditions in the Mediterranean, reflecting enhanced Nile flow due to intense African monsoonal conditions, and marking the impact of the tropical precession cycles on Eastern Mediterranean hydroclimate. This pattern was lost during MIS 2,3,4, when mostly sequences of primary aragonite are punctuated by gypsum precipitation during Heinrich events, marking the strong impact of the North Atlantic on the last glacial Levant hydroclimate. © 2020 Elsevier Ltd 2020 English 02773791 10.1016/j.quascirev.2020.106460 Quaternary Science Reviews 244 Elsevier Ltd Lamont-Doherty Earth Observatory of Columbia University, 61 Route 9W, Palisades, NY 10964, United States; Department of Earth and Environmental Sciences, Columbia University, 61 Route 9W, Palisades, NY 10964, United States; Department of Earth and Planetary Sciences, Weizmann Institute of Science, Rehovot, Israel; The Fredy and Nadine Hermann Institute of Earth Sciences, The Hebrew University, Edmond J. Safra Campus, Jerusalem, 91904, Israel; The Interuniversity Institute for Marine Sciences, Coral Beach, Eilat, 88103, Israel; Graduate School of Environmental Studies, Nagoya University, Japan University of Nagoya, Chikusa-ku, Nagoya, 464-8601, Japan; Department of Geosciences, The University of Arizona, 1040 E 4th St, Tucson, AZ 85721, United States; Geological Survey of Israel, 32 Yashayahu Leibowitz St., Jerusalem, 95501, Israel Carbonate minerals; Caves; Driers (materials); Glacial geology; Incident solar radiation; Infill drilling; Isotopes; Lakes; Sedimentology, Climate condition; Eastern Mediterranean; Gypsum precipitation; Heinrich Events; Marine isotope stages; Northern Hemispheres; Oxygen isotopes; Sedimentary facies, Core drilling, aragonite; chronology; climate conditions; climate cycle; Deep Sea Drilling Project; hydrometeorology; insolation; marine isotope stage; Northern Hemisphere; watershed; wetting-drying cycle, Atlantic Ocean; Atlantic Ocean (North); Dead Sea; Mediterranean Sea; Mediterranean Sea (East) https://www.scopus.com/inward/record.uri?eid=2-s2.0-85089277951&doi=10.1016%2fj.quascirev.2020.106460&partnerID=40&md5=adaf008c3188a277cc71cdbaa6cdca0d cited By 18 S.L. Goldstein Y. Kiro A. Torfstein H. Kitagawa J. Tierney M. Stein article Liu2020 The Hartoušov mofette system is a natural CO2 degassing site in the central Cheb Basin (Eger Rift, Central Europe). In early 2016 a 108 m deep core was obtained from this system to investigate the impact of ascending mantle-derived CO2 on indigenous deep microbial communities and their surrounding life habitat. During drilling, a CO2 blow out occurred at a depth of 78.5 meter below surface (mbs) suggesting a CO2 reservoir associated with a deep low-permeable CO2-saturated saline aquifer at the transition from Early Miocene terrestrial to lacustrine sediments. Past microbial communities were investigated by hopanoids and glycerol dialkyl glycerol tetraethers (GDGTs) reflecting the environmental conditions during the time of deposition rather than showing a signal of the current deep biosphere. The composition and distribution of the deep microbial community potentially stimulated by the upward migration of CO2 starting during Mid Pleistocene time was investigated by intact polar lipids (IPLs), quantitative polymerase chain reaction (qPCR), and deoxyribonucleic acid (DNA) analysis. The deep biosphere is characterized by microorganisms that are linked to the distribution and migration of the ascending CO2-saturated groundwater and the availability of organic matter instead of being linked to single lithological units of the investigated rock profile. Our findings revealed high relative abundances of common soil and water bacteria, in particular the facultative, anaerobic and potential iron-oxidizing Acidovorax and other members of the family Comamonadaceae across the whole recovered core. The results also highlighted the frequent detection of the putative sulfate-oxidizing and CO2-fixating genus Sulfuricurvum at certain depths. A set of new IPLs are suggested to be indicative for microorganisms associated to CO2 accumulation in the mofette system. © Copyright © 2020 Liu, Adler, Lipus, Kämpf, Bussert, Plessen, Schulz, Krauze, Horn, Wagner, Mangelsdorf and Alawi. Article 2020 English 1664302X 10.3389/fmicb.2020.543260 Frontiers in Microbiology 11 Frontiers Media S.A. biological marker; carbon; carbon dioxide; carbon nitrogen sulfur monocycle; clario star; fluorescein sodium; ground water; organic carbon; organic nitrogen; RNA 16S; soil organic matter; urea; Acidobacteria; Actinobacteria; Alphaproteobacteria; Arabidopsis thaliana; Article; bacterial microbiome; Bacteroidetes; Betaproteobacteria; biogeography; bioinformatics; biosphere; calibration; carbon dioxide fixing bacterium; Chloroflexi; column chromatography; Comamonadaceae; community structure; Crenarchaeota; cyanobacterium; DNA extraction; DNA purification; electrospray mass spectrometry; Escherichia coli; freeze drying; Gallionella; Gammaproteobacteria; gene sequence; geochemical analysis; high performance liquid chromatography; homogenate; isotope analysis; lipid analysis; liquid chromatography; methanogenesis; Methanosaeta; Methanosarcina; microbial biomass; microbial community; microbial contamination; microbial diversity; migration; Miocene; multidimensional scaling; nonhuman; organisms by metabolism; population abundance; real time polymerase chain reaction; saponification; soil microflora; stratigraphy; sulfate oxidizing bacterium; Sulfuricurvum; thermal spring; total nitrogen content; total organic carbon; ultra performance liquid chromatography https://www.scopus.com/inward/record.uri?eid=2-s2.0-85098243597&doi=10.3389%2ffmicb.2020.543260&partnerID=40&md5=f4ea3e97ac30c6c68bb32263cc60ba01 Cited by: 4; All Open Access, Gold Open Access, Green Open Access Qi Liu Karsten Adler Daniel Lipus Horst Kämpf Robert Bussert Birgit Plessen Hans-Martin Schulz Patryk Krauze Fabian Horn Dirk Wagner Kai Mangelsdorf Mashal Alawi article Andreev2020 The 318-m long sediment record from Lake El'gygytgyn, NE Russia situated in the present-day herb tundra zone, provides a unique archive of high Arctic environmental changes since ca 3.6 million years ago (Ma). This paper focuses on pollen-derived vegetation change during the mid-Pliocene Warm Period (mPWP) and in particular during Marine Isotope Stage (MIS) M2, which is known to represent the coldest interval of the Pliocene. Building on initial pollen studies, we provide a more complete record and a more detailed discussion of climatically-driven vegetation and environmental changes in the northeastern Russian Arctic, spanning the 203-thousand-year interval between 3.383 and 3.180 Ma ago. Pine-spruce-fir-larch-Douglas fir forests dominated the area around Lake El'gygytgyn between 3.383 and 3.330 Ma (MIS MG4 - MIS MG2). Colder and drier climate caused a decrease of coniferous forests and widespread Sphagnum habitats around the lake between 3.370 and 3.357 Ma. After 3.3 Ma, the presence of spruce, fir and Douglas fir decreased again. A very pronounced cooling took place at the first half of MIS M2 (3.312–3.283 Ma), when treeless tundra- and steppe-like habitats became common in the regional vegetation. Climate conditions were similar or only slightly warmer and wetter to those of the Holocene. Numerous coprophilous fungi spores identified in the MIS M2 pollen samples suggest the presence of grazing mammals around the lake. Larch-pine forests with some spruce started to dominate the area again after ca. 3.282 Ma, thus pointing to a significant climate amelioration during the mPWP. However, the forested area decreased, while herb- and shrub-dominated vegetation spread again during MIS KM6 (especially 3.235–3.223 Ma), suggesting a noticeable climatic deterioration and relatively cold and dry conditions. © 2020 Elsevier B.V. 2020 English 09218181 10.1016/j.gloplacha.2019.103111 Global and Planetary Change 186 Elsevier B.V. Alfred Wegener Institute, Research Unit Potsdam, Telegrafenberg A43, Potsdam, 14473, Germany; Institute of Geology and Mineralogy, University of Cologne, Zülpicher 49a, Cologne, 50674, Germany; Institute of Geology and Petroleum Technologies, Kazan Federal University, Kremlyovskaya 18, Kazan, 420008, Russian Federation; Freie Universität Berlin, Institute of Geological Sciences, Paleontology, Malteserstr. 74-100, Building D, Berlin, 12249, Germany Deterioration; Ecosystems; Forestry; Lakes; Mammals, Coniferous forests; Environmental change; Marine isotope stages; Mid-Pliocene; Pollen; Russian Arctic; Vegetation change; Vegetation history, Vegetation, environmental change; fungus; grazing; Pliocene; pollen; vegetation history, Chukchi; Elgygytgyn Lake; Russian Federation, Abies; Fungi; Larix; Mammalia; Picea; Pseudotsuga; Pseudotsuga menziesii; Sphagnum https://www.scopus.com/inward/record.uri?eid=2-s2.0-85077502507&doi=10.1016%2fj.gloplacha.2019.103111&partnerID=40&md5=abcbde225ff0ddcc809ccb56fd56e40b cited By 4 A.A. Andreev P.E. Tarasov V. Wennrich M. Melles article Fischer2020983 Monitoring of CO2 degassing in seismoactive areas allows the study of correlations of gas release and seismic activity. Reliable continuous monitoring of the gas flow rate in rough field conditions requires robust methods capable of measuring gas flow at different types of gas outlets such as wet mofettes, mineral springs, and boreholes. In this paper we focus on the methods and results of the long-term monitoring of CO2 degassing in the West Bohemia/Vogtland region in central Europe, which is typified by the occurrence of earthquake swarms and discharge of carbon dioxide of magmatic origin. Besides direct flow measurement using flowmeters, we introduce a novel indirect technique based on quantifying the gas bubble contents in a water column, which is capable of functioning in severe environmental conditions. The method calculates the mean bubble fraction in a water-gas mixture from the pressure difference along a fixed depth interval in a water column. Laboratory tests indicate the nonlinear dependence of the bubble fraction on the flow rate, which is confirmed by empirical models found in the chemical and nuclear engineering literature. Application of the method in a pilot borehole shows a high correlation between the bubble fraction and measured gas flow rate. This was specifically the case for two coseismic anomalies in 2008 and 2014, when the flow rate rose during a seismic swarm to a multitude of the preseismic level for several months and was followed by a long-term flow rate decline. However, three more seismic swarms occurring in the same fault zone were not associated with any significant CO2 flow anomaly.We surmise that this could be related to the slightly farther distance of the hypocenters of these swarms compared to the two ones which caused the coseismic CO2 flow rise. Further long-term CO2- flow monitoring is required to verify the mutual influence of CO2 degassing and seismic activity in the area. © 2020 Cambridge University Press. All rights reserved. Article 2020 English 18699510 10.5194/se-11-983-2020 Solid Earth 11 Copernicus GmbH 983 – 998 3 Bohemia; Czech Republic; Boreholes; Carbon dioxide; Degassing; Earthquakes; Flow measurement; Flow of gases; Gases; Mineral springs; Bubble fractions; Continuous monitoring; Earthquake swarms; Environmental conditions; Field conditions; Long term monitoring; Nonlinear dependence; Pressure differences; carbon dioxide; coseismic process; crustal structure; degassing; discharge; earthquake hypocenter; earthquake swarm; flow velocity; gas flow; monitoring; Flow rate https://www.scopus.com/inward/record.uri?eid=2-s2.0-85086400975&doi=10.5194%2fse-11-983-2020&partnerID=40&md5=da43d9414beaa01569d3cda80dbc4adb Cited by: 6; All Open Access, Gold Open Access, Green Open Access Tomáš Fischer Josef Vlček Martin Lanzendörfer article Woith2020 Fluid anomalies were often considered as possible precursors before earthquakes. However, fluid properties at the surface can change for a variety of reasons, including environmental changes near the surface, the response of the superficial fluid system to loads associated with the mechanical nucleation of earthquake fractures, or as a result of transients in fluid flow from the depths. A key problem is to understand the origin of the anomaly and to distinguish between different causes. We present a new approach to monitor geochemical and geophysical fluid properties along a vertical profile in a set of drillings from a depth of a few hundred meters to the surface. This setup can provide hints on the origin of temporal variations, as the migration direction and speed of properties can be measured. In addition, potential admixtures of fluids from a deep crustal or mantle origin with meteoric fluids can be better quantified. A prototype of a multi-level gas monitoring system comprising flow and pressure probes, as well as monitoring of fluid-geochemical properties and stable isotopes is being implemented in a mofette field with massive CO2 (up to 97 tons per day) degassing. The mofette is believed a gas emission site where CO2 ascends through crustal-scale conduits from as deep as the upper mantle, and may therefore provide a natural window to ongoing magmatic processes at mantle depth. Fluids from three adjacent boreholes—30, 70, and 230 m deep—will be continuously monitored at high sampling rates. © Copyright © 2020 Woith, Daskalopoulou, Zimmer, Fischer, Vlček, Trubač, Rosberg, Vylita and Dahm. Article 2020 English 22966463 10.3389/feart.2020.585733 Frontiers in Earth Science 8 Frontiers Media S.A. Carbon dioxide; Earthquakes; Gas detectors; Geochemistry; Earthquake research; Environmental change; Gas monitoring systems; Geochemical properties; High sampling rates; Magmatic process; Temporal variation; Vertical profile; carbon dioxide; crustal structure; degassing; drilling; earthquake mechanism; earthquake swarm; fluid flow; fluid pressure; geochemistry; geophysics; hydrocarbon reservoir; monitoring; radon; Flow of fluids https://www.scopus.com/inward/record.uri?eid=2-s2.0-85095701694&doi=10.3389%2ffeart.2020.585733&partnerID=40&md5=4d18b65e05e23efba7c6dabf297cf33f Cited by: 4; All Open Access, Gold Open Access Heiko Woith Kyriaki Daskalopoulou Martin Zimmer Tomáš Fischer Josef Vlček Jakub Trubač Jan-Erik Rosberg Tomáš Vylita Torsten Dahm article Kouamelan2020 Limited to the Atlantic and its surrounding basins, the expression of the Coniacian–Santonian oceanic anoxic event (OAE3) was discovered in the non-marine Cretaceous Songliao Basin, Eastern Asia not long ago. In this study, based on spectral gamma ray logs data recorded in three basins, the self-similarity of the OAE3 was studied through the analysis of the scaling properties of thorium–potassium and thorium–uranium distributions both in marine and terrestrial environments using the multifractal detrending fluctuation analysis. The results indicate that, in both marine and terrestrial systems, the OAE3 intervals are characterized by their multifractal nature due to long-range correlation. However, the multifractal features of the studied OAE3 intervals are different in the three basins, although some common trends were observed. By comparing the degree of multifractality of the OAE3 deposits with the clay minerals and the redox conditions, it appears that the changes of the multifractal features are controlled by local changes such as clay mineralogy and redox conditions in both milieus under different sedimentation patterns. At all sites, the left side shortened spectrum of the thorium–potassium distribution suggests the presence of local fluctuations with minor amplitudes during the OAE3. Furthermore, the shortened singularity spectrum of the thorium–uranium distribution reflects the existence of small-scale fluctuations with large amplitudes at marine sites while in the non-marine Songliao Basin, the thorium–uranium distribution suggests the presence of local fluctuations with small amplitudes during the OAE3. Therefore, a more local behavior of the event is considered although the regional character is not neglected. © 2020, The Author(s). 2020 English 20452322 10.1038/s41598-020-71327-w Scientific Reports 10 Nature Research Key Laboratory of Geo-Detection (China University of Geosciences, Beijing), Ministry of Education, Beijing, 100083, China; School of Geophysics and Information Technology, China University of Geosciences, Beijing, 100083, China; Institute of Earth Sciences, China University of Geosciences, Beijing, 100083, China; School of Earth Science and Resources, China University of Geosciences, Beijing, 100083, China; Petroleum Engineering Department, Faculty of Mineral Resources Technology, University of Mines and Technology, Tarkwa, Ghana 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85090040119&doi=10.1038%2fs41598-020-71327-w&partnerID=40&md5=03cc21fd9c56249f725275fbb3302082 cited By 2 K.S. Kouamelan C. Zou C. Wang K.R. Assie C. Peng O.R. Mondah K.A. N’dri E.T. Brantson article Yu20201049 2020 English 20959273 10.1016/j.scib.2020.03.039 Science Bulletin 65 Elsevier B.V. 1049-1051 State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, 100029, China; College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China; Innovation Academy for Earth Science, Chinese Academy of Sciences, Beijing, 100029, China 13 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85083004425&doi=10.1016%2fj.scib.2020.03.039&partnerID=40&md5=dbe8d79c191e7f242ebc1936f1175de9 cited By 11 Z. Yu H. He C. Deng K. Lu Z. Shen Q. Li article katayama2020permeability Permeability profiles in the crust-mantle sequences of the Samail ophiolite were constructed based on onboard measurements of the electrical resistivity of cores recovered during the Oman Drilling Project. For each sample, we measured dry and brine-saturated resistivity during the description campaign on the drilling vessel Chikyu. Owing to the conductive brine in the pore space, wet resistivity is systematically lower than dry resistivity. The difference between dry and wet resistivity is attributed to the movement of dissolved ions in brine that occupies the pore space. We applied effective medium theory to calculate the volume fraction of pores that contribute to electrical transport. Using an empirical cubic law between transport porosity and permeability, we constructed permeability profiles for the crust-mantle transition zone and the serpentinized mantle sections in the Samail ophiolite. The results indicate that (1) the gabbro sequence has a markedly lower permeability than the underlying mantle sequence; (2) serpentinized dunites have higher permeability than serpentinized harzburgites; and (3) discrete sample permeability is correlated with ultrasonic velocity, suggesting that the permeability variations predominately reflect crack density and geometry. ©2020. American Geophysical Union. All Rights Reserved. 2020 English 21699313 10.1029/2019JB018698 Journal of Geophysical Research: Solid Earth 125 Wiley Online Library e2019JB018698 Department of Earth and Planetary Systems Science, Hiroshima University, Hiroshima, Japan; Mantle Drilling Promotion Office, MarE3, JAMSTEC, Kanagawa, Japan; Kochi Institute for Core Sample Research, JAMSTEC, Kochi, Japan; Department of Geosciences, University of Oslo, Oslo, Norway; Earth and Environmental Sciences, Seoul National University, Seoul, South Korea; Department of Geology, University of Maryland, College Park, MD, United States; Department of Earth and Planetary Sciences, Nagoya University, Aichi, Japan; Géosciences Montpellier, CNRS, Université de Montpellier, Montpellier, France; Lamont Doherty Earth Observatory, Columbia University, New York, NY, United States 8 crust-mantle boundary; dunite; electrical resistivity; gabbro; harzburgite; ophiolite; permeability; porosity; transition zone https://www.scopus.com/inward/record.uri?eid=2-s2.0-85089842179&doi=10.1029%2f2019JB018698&partnerID=40&md5=72c5ef576dc772bad94115a1121d4e9b cited By 9 Ikuo Katayama Natsue Abe Kohei Hatakeyama Yuya Akamatsu Keishi Okazaki Ole Ivar Ulven Gilbert Hong Wenlu Zhu Benoit Cordonnier Katsuyoshi Michibayashi others article Pieńkowski2020 Review 2020 10.1016/j.earscirev.2020.103383 Earth-Science Reviews 210 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85092530913&doi=10.1016%2fj.earscirev.2020.103383&partnerID=40&md5=8aca6c4b9e05684a972dedc167c38f51 Cited by: 26; All Open Access, Green Open Access, Hybrid Gold Open Access Grzegorz Pieńkowski Stephen P. Hesselbo Maria Barbacka Melanie J. Leng article Kummerow2020 Article 2020 10.1016/j.jvolgeores.2018.05.014 Journal of Volcanology and Geothermal Research 391 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85048866149&doi=10.1016%2fj.jvolgeores.2018.05.014&partnerID=40&md5=b849279c887c4cecadc7de81d48c3a3f Cited by: 8 Juliane Kummerow Siegfried Raab Jan A. Schuessler Romain Meyer article moore2020observations 2020 10.33112/surtsey.14.3 Surtsey Res 14 33--45 James G Moore Marie D Jackson article Lyons202025327 An asteroid impact in the Yucatán Peninsula set off a sequence of events that led to the Cretaceous-Paleogene (K-Pg) mass extinction of 76% species, including the nonavian dinosaurs. The impact hit a carbonate platform and released sulfate aerosols and dust into Earth's upper atmosphere, which cooled and darkened the planet - a scenario known as an impact winter. Organic burn markers are observed in K-Pg boundary records globally, but their source is debated. If some were derived from sedimentary carbon, and not solely wildfires, it implies soot from the target rock also contributed to the impact winter. Characteristics of polycyclic aromatic hydrocarbons (PAHs) in the Chicxulub crater sediments and at two deep ocean sites indicate a fossil carbon source that experienced rapid heating, consistent with organic matter ejected during the formation of the crater. Furthermore, PAH size distributions proximal and distal to the crater indicate the ejected carbon was dispersed globally by atmospheric processes. Molecular and charcoal evidence indicates wildfires were also present but more delayed and protracted and likely played a less acute role in biotic extinctions than previously suggested. Based on stratigraphy near the crater, between 7.5 × 1014and 2.5 × 1015g of black carbon was released from the target and ejected into the atmosphere, where it circulated the globe within a few hours. This carbon, together with sulfate aerosols and dust, initiated an impact winter and global darkening that curtailed photosynthesis and is widely considered to have caused the K-Pg mass extinction. © 2020 National Academy of Sciences. All rights reserved. 2020 10.1073/pnas.2004596117 Proceedings of the National Academy of Sciences of the United States of America 117 25327-25334 Department of Geosciences, Pennsylvania State University, University Park, PA 16802, United States; Western Australia Organic and Isotope Geochemistry Centre, School of Earth and Planetary Sciences, Institute for Geoscience Research, Curtin University, Perth, WA 6102, Australia; Institute for Geophysics, University of Texas at Austin, Austin, TX 78758, United States; Department of Geological Sciences, University of Texas at Austin, Austin, TX 78712, United States; Center for Planetary Systems Habitability, University of Texas at Austin, Austin, TX 78712, United States; Department of Earth Science and Engineering, Imperial College London, London, SW7 2AZ, United Kingdom 41 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85092914280&doi=10.1073%2fpnas.2004596117&partnerID=40&md5=a4ab4b648612480f4fe423fff4fa27fc cited By 24 S.L. Lyons A.T. Karp T.J. Bralower K. Grice B. Schaefer S.P.S. Gulick J.V. Morgan K.H. Freeman article Bralower2020 Microcrystalline calcite (micrite) dominates the sedimentary record of the aftermath of the Cretaceous–Paleogene (K–Pg) impact at 31 sites globally, with records ranging from the deep ocean to the Chicxulub impact crater, over intervals ranging from a few centimeters to more than seventeen meters. This micrite-rich layer provides important information about the chemistry and biology of the oceans after the impact. Detailed high-resolution scanning electron microscopy demonstrates that the layer contains abundant calcite crystals in the micron size range with a variety of forms. Crystals are often constructed of delicate, oriented agglomerates of sub-micrometer mesocrystals indicative of rapid precipitation. We compare the form of crystals with natural and experimental calcite to shed light on their origin. Close to the crater, a significant part of the micrite may derive from the initial backreaction of CaO vaporized during impact. In more distal sites, simple interlocking rhombohedral crystals resemble calcite precipitated from solution. Globally, we found unique calcite crystals associated with fossilized extracellular materials that strikingly resemble calcite precipitated by various types of bacteria in natural and laboratory settings. The micrite-rich layer contains abundant bacterial and eukaryotic algal biomarkers and most likely represents global microbial blooms initiated within millennia of the K–Pg mass extinction. Cyanobacteria and non-haptophyte microalgae likely proliferated as dominant primary producers in cold immediate post-impact environments. As surface-water saturation state rose over the following millennia due to the loss of eukaryotic carbonate producers and continuing river input of alkalinity, “whitings” induced by cyanobacteria replaced calcareous nannoplankton as major carbonate producers. We postulate that the blooms grew in supersaturated surface waters as evidenced by crystals that resemble calcite precipitates from solution. The microbial biomass may have served as a food source enabling survival of a portion of the marine biota, ultimately including life on the deep seafloor. Although the dominance of cyanobacterial and algal photosynthesis would have weakened the biological pump, it still would have removed sufficient nutrients from surface waters thus conditioning the ocean for the recovery of biota at higher trophic levels. © 2020 Elsevier B.V. 2020 10.1016/j.epsl.2020.116476 Earth and Planetary Science Letters 548 Department of Geosciences, Pennsylvania State University, University Park, PA 16802, United States; Department of Geosciences, Earth and Environmental Systems Institute, Pennsylvania State University, University Park, PA 16802, United States; Department of Earth Science and Engineering, Imperial College, London, United Kingdom; Department of Geology, The University of Kansas, Lawrence, KS 66045, United States; WA-Organic and Isotope Geochemistry Centre, The Institute for Geoscience Research, School of Earth and Planetary Science, Curtin University, Perth, WA, Australia; Institute of Geosciences, Friedrich-Schiller-University Jena, Burgweg 11, Jena, 07749, Germany; Earth and Planetary Sciences, University of California Santa Cruz, 1156 High Street, Santa Cruz, CA 95064, United States; Planetary Science Institute, Tucson, AZ, United States; Institute for Geophysics, Dept. of Geological Sciences, Jackson School of Geosciences, Center for Planetary Systems Habitability, University of Texas at Austin, United States; Institute for Geophysics, Jackson School of Geosciences, University of Texas at Austin, United States; Department of Geology and Geophysics, Yale University, New Haven, CT 06520, United States; Department of Earth & Environmental Sciences, Wesleyan University, Middletown, CT 06459, United States; Department of Palaeobiology, Swedish Museum of Natural History, Stockholm, Sweden https://www.scopus.com/inward/record.uri?eid=2-s2.0-85089102470&doi=10.1016%2fj.epsl.2020.116476&partnerID=40&md5=1eb387da505f135a88234d62fe83d75d cited By 20 T.J. Bralower J. Cosmidis P.J. Heaney L.R. Kump J.V. Morgan D.T. Harper S.L. Lyons K.H. Freeman K. Grice J.E. Wendler J.C. Zachos N. Artemieva S.A. Chen S.P.S. Gulick C.H. House H.L. Jones C.M. Lowery C. Nims B. Schaefer E. Thomas V. Vajda article Hatfield2020 Normalized remanence, a proxy for relative geomagnetic paleointensity, along with radiocarbon and U-Th age constraints, facilitates the generation of a well-constrained chronology for sediments recovered during International Continental Scientific Drilling Program (ICDP) coring of Lake Junín, Peru. The paleomagnetic record of the ∼88 m stratigraphic section from Lake Junín was studied, and rock magnetic variability constrained, through analysis of 109 u-channel samples and 56 discrete samples. Downcore variations in sediment lithology reflect climate and hydrological processes over glacial-interglacial time frames and these changes are strongly reflected in the bulk magnetic properties. Glacial sediments are characterized by higher detrital silt content, higher magnetic susceptibility and magnetic remanence values, and a magnetic coercivity that is characteristic of ferrimagnetic (titano)magnetite and/or maghemite. Interglacial sediments and low lake-level facies are dominated by carbonate lithologies and/or peat horizons that result in lower magnetic concentration values. Sediments with moderately high Natural Remanent Magnetization (NRM) intensity (&gt;1 × 10–3 A/m) have well resolved component directions and inclination values that vary around geocentric axial dipole expectations. This remanence value can be used as a threshold to filter the lowest quality paleomagnetic data from the record. Normalized NRM intensity values are also sensitive to lithologic variability, but following NRM remanence filtering, only the highest quality ferrimagnetic dominated data are retained which then show no coherence with bulk magnetic properties. Constrained by the existing radiocarbon based chronology over the last 50 kyrs and 18 U-Th age constraints that are restricted to five interglacial sediment packages, filtered normalized remanence parameters compare well with global relative paleointensity stacks, suggesting relative variations in geomagnetic intensity are preserved. By adjusting the existing age-depth model we improve the correlation between the Junín normalized intensity record and a well-dated RPI stack and RPI model. We then incorporate these paleomagnetic tie points with the existing radiometric dates using a modeling approach to assess uncertainty and refine the age-depth model for Lake Junín. In combining relative and radiometric dating, the new age-depth model captures glacial-interglacial variations in sedimentation rate and improves the orbital-scale age model for the sediments accumulated in Lake Junín basin over most of the Brunhes. © Copyright © 2020 Hatfield, Stoner, Solada, Morey, Woods, Chen, McGee, Abbott and Rodbell. 2020 English 22966463 10.3389/feart.2020.00147 Frontiers in Earth Science 8 Frontiers Media S.A. Department of Geological Sciences, University of Florida, Gainesville, FL, United States; College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR, United States; Department of Geology and Environmental Science, University of Pittsburgh, Pittsburgh, PA, United States; Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, United States; Department of Geology, Union College, Schenectady, NY, United States Binary alloys; Ferrimagnetism; Geomagnetism; Glacial geology; Lakes; Lithology; Magnetic susceptibility; Magnetite; Natural resources management; Radiometry; Remanence; Stratigraphy; Thorium alloys; Uncertainty analysis; Uranium alloys, Continental scientific drillings; Geomagnetic intensity; Hydrological process; Interglacial sediments; Magnetic coercivities; Magnetic concentration; Natural remanent magnetization; Relative paleointensity, Sediments, age determination; Brunhes chron; chronology; geomagnetism; lacustrine deposit; paleointensity; paleomagnetism; remanent magnetization; stratigraphy, Junin; Lake Junin; Peru https://www.scopus.com/inward/record.uri?eid=2-s2.0-85086510575&doi=10.3389%2ffeart.2020.00147&partnerID=40&md5=0297c6b1814dc403b33bb2f013e82327 cited By 7 R.G. Hatfield J.S. Stoner K.E. Solada A.E. Morey A. Woods C.Y. Chen D. McGee M.B. Abbott D.T. Rodbell article Chang2020 To better illuminate structural discontinuities around the San Andreas Fault Observatory at Depth (SAFOD) site, following the previous study of Zhang et al. (2009), we have extended the Generalized Radon Transform (GRT) method to jointly use scattered P and SH waves from abundant local earthquakes recorded by a local dense seismic network. A hybrid imaging condition is applied to extract consistent structures from scattered P and SH images. In this way, more robust structure information can be determined from separate images with potential artifacts. For the transverse component waveforms, coherent S-S scattered waves after the direct SH waves can be clearly identified, and they are less interfered with by other scattered and converted waves compared to scattered P-P waves on the vertical component. Similar to Zhang, Wang, et al. (2009), near-vertical reflectors are imaged on both sides of the San Andreas Fault (SAF) with scattered SH waves, which is generally consistent with the imaging results using scattered P-P waves from local earthquakes and a wide-angle active seismic reflection profile. Compared to the P-P scattering imaging result, the imaging result using scattered SH waves has higher resolution due to shorter S wavelength and cleaner S-S scattered waveforms, and the SAF, as well as other reflectors around it, is better resolved. Although the resolution of the joint image obtained by combining separate imaging results from different scattered waves may be degraded, it is able to more robustly characterize strong structure discontinuities using passive seismic sources. © 2020. American Geophysical Union. All Rights Reserved. 2020 English 21699313 10.1029/2019JB019017 Journal of Geophysical Research: Solid Earth 125 Blackwell Publishing Ltd Laboratory of Seismology and Physics of Earth Interior, School of Earth and Space Sciences, University of Science and Technology of China, Hefei, China; Mengcheng National Geophysical Observatory, University of Science and Technology of China, Hefei, China; CAS Center for Excellence in Comparative Planetology, University of Science and Technology of China, Hefei, China 9 P-wave; Radon transform; San Andreas Fault; seismic source; seismic tomography; SH-wave; structural geology; wave scattering, California; Parkfield; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-85091536384&doi=10.1029%2f2019JB019017&partnerID=40&md5=6132529ff74e50428f517f4d0dd86ee4 cited By 0 K. Chang H. Zhang article Soreghan202093 Chamberlin and Salisbury's assessment of the Permian a century ago captured the essence of the period: it is an interval of extremes yet one sufficiently recent to have affected a biosphere with near-modern complexity. The events of the Permian - the orogenic episodes, massive biospheric turnovers, both icehouse and greenhouse antitheses, and Mars-analog lithofacies - boggle the imagination and present us with great opportunities to explore Earth system behavior. The ICDP-funded workshops dubbed "Deep Dust," held in Oklahoma (USA) in March 2019 (67 participants from nine countries) and Paris (France) in January 2020 (33 participants from eight countries), focused on clarifying the scientific drivers and key sites for coring continuous sections of Permian continental (loess, lacustrine, and associated) strata that preserve high-resolution records. Combined, the two workshops hosted a total of 91 participants representing 14 countries, with broad expertise. Discussions at Deep Dust 1.0 (USA) focused on the primary research questions of paleoclimate, paleoenvironments, and paleoecology of icehouse collapse and the run-up to the Great Dying and both the modern and Permian deep microbial biosphere. Auxiliary science topics included tectonics, induced seismicity, geothermal energy, and planetary science. Deep Dust 1.0 also addressed site selection as well as scientific approaches, logistical challenges, and broader impacts and included a mid-workshop field trip to view the Permian of Oklahoma. Deep Dust 2.0 focused specifically on honing the European target. The Anadarko Basin (Oklahoma) and Paris Basin (France) represent the most promising initial targets to capture complete or near-complete stratigraphic coverage through continental successions that serve as reference points for western and eastern equatorial Pangaea. © 2020 Copernicus GmbH. All rights reserved. 2020 English 18168957 10.5194/sd-28-93-2020 Scientific Drilling 28 Copernicus GmbH 93-112 School of Geosciences, University of Oklahoma, Norman, OK 73019, United States; BRGM, Orléans, 45060, France; Geology and Geography, West Virginia University, Morgantown, VA 26506, United States; Université de Rennes, CNRS, Géosciences Rennes - UMR 6118, Rennes, 35000, France; Earth System Analysis, Potsdam Institute for Climate Impact Research, Potsdam, Germany; Department of Biology, Kyushu University, Fukuoka, 819-0395, Japan; Jack Satterly Geochronology Laboratory, University of Toronto, Toronto, ON M5S3B1, Canada; Space Sciences Institute, Boulder, CO 80301, United States; Atmospheric, Oceanic, and Earth Sciences, George Mason University, Fairfax, GA 22030, United States; Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, United States; Department of Integrative Biology, University of California-Berkeley, Berkeley, CA 94720, United States; Laboratoire de Planétologie, Géodynamique Université de Nantes, Nantes Cedex, 44322, France; Geology Department, Beloit College, Beloit, WI 53511, United States Biospherics; Geothermal energy; Greenhouses; Induced Seismicity; Site selection; Stratigraphy; Warehouses, Broader impacts; Continental climate; High resolution; Late Paleozoic; Paleoenvironments; Planetary science; Reference points; Research questions, Dust https://www.scopus.com/inward/record.uri?eid=2-s2.0-85097220861&doi=10.5194%2fsd-28-93-2020&partnerID=40&md5=d454a3dec132956d24f9845e5ec095d1 cited By 1 G.S. Soreghan L. Beccaletto K.C. Benison S. Bourquin G. Feulner N. Hamamura M. Hamilton N.G. Heavens L. Hinnov A. Huttenlocker C. Looy L.S. Pfeifer S. Pochat M. Sardar Abadi J. Zambito Deep Dust participants article Wu20203502 To solve the problem of drilling in severely cracked hard rock in deep high temperature and high pressure (HTHP) stratum of Well Songke-2, mechanical analysis and physical simulation experiment were used to clarify the factors affecting the thickness of the plugging layer in this study. The sealing effect of high-strength skeleton particles and HT deformable soften particles was verified through HTHP filtration test, and the on-site operation pressure was calculated and controlled. The self-locking mechanical model of the three-particle bridge group skeleton was established, and the anti-destructive ability formula of the single bridge group was derived. Compared with the blank formula, emulsified asphalt, oxidized asphalt and sulfonated asphalt can reduce the HTHP water loss volume by 56%, 44% and 48%, respectively. Particle size and strength, crack width and pressure difference have important influence on the thickness of the plugging layer. A quick blocking effect can be achieved by combining the rigid plugging agent with deformable plugging particles. Based on the above analysis and tests, the drilling pressure in the operation was effectively controlled in conjunction with the on-site technology, and the compaction and anti-collapse effect under moderate positive pressure difference was realized. With the techniques mentioned above, the fifth spud of Well Songke-2 was completed successfully with the open-hole section from 5 910 to 7 018 m. © 2020, Editorial Department of Earth Science. All right reserved. Article 2020 Chinese 10002383 10.3799/dqkx.2019.121 Diqiu Kexue - Zhongguo Dizhi Daxue Xuebao/Earth Science - Journal of China University of Geosciences 45 China University of Geosciences 3502 – 3508 9 Asphalt; Cracks; Deformation; Drilling fluids; Emulsification; Infill drilling; Musculoskeletal system; Particle size; Pressure effects; Drilling fluid systems; Emulsified asphalts; High temperature and high pressures (HTHP); Mechanical analysis; Physical simulation experiment; Positive pressure; Pressure differences; Wellbore stability; Particle size analysis https://www.scopus.com/inward/record.uri?eid=2-s2.0-85092652458&doi=10.3799%2fdqkx.2019.121&partnerID=40&md5=18d83be6423938999a26c2cc5042d893 Cited by: 0 Xiaoming Wu Wenlong Zheng Yuliang Zou article An202063 The Weihe Basin, enclosed by the Chinese Loess Plateau to the north and the Qinling Mountains to the south, is an outstanding, world-class continental site for obtaining high-resolution multi-proxy records that reflect environmental changes spanning most of the Cenozoic. Previous geophysical and sedimentary studies indicate that the basin hosts 6000-8000 m thick fluvial-lacustrine sedimentary successions spanning the Eocene to Holocene. This sedimentary record provides an excellent and unique archive to decipher long-term tectonic-climate interactions related to the uplift of the Tibetan Plateau, the onset/evolution of the Asian monsoon, and the development of the biogeography of East Asia. Owing to its location at the interface of the opposing westerly and Asian monsoon circulation systems, the Weihe Basin also holds enormous promise for providing a record of changes in these circulation systems in response to very different boundary conditions since the Eocene. To develop an international scientific drilling programme in the Weihe Basin, the Institute of Earth Environment, Chinese Academy of Sciences, organized a dedicated workshop with 55 participants from eight countries. The workshop was held in Xi'an, China, from 15 to 18 October 2019. Workshop participants conceived the key scientific objectives of the envisaged Weihe Basin Drilling Project (WBDP) and discussed technical and logistical aspects as well as the scope of the scientific collaboration in preparation for a full drilling proposal for submission to the International Continental Scientific Drilling Program (ICDP). Workshop participants mutually agreed to design a two-phase scientific drilling programme that will in a first phase target the upper 3000 m and in a second phase the entire up to 7500 m thick sedimentary infill of the basin. For the purpose of the 7500 m deep borehole, the world's only drill rig for ultra-deep scientific drilling on land, Crust 1, which previously recovered the entire continental Cretaceous sediments in the Songliao Basin, will be deployed in the WBDP. © 2020 Copernicus GmbH. All rights reserved. 2020 English 18168957 10.5194/sd-28-63-2020 Scientific Drilling 28 Copernicus GmbH 63-73 State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, 710061, China; CAS Center for Excellence in Quaternary Science and Global Change, Xi'an, 710061, China; School of Earth Sciences and Engineering, Sun Yat-Sen University, Guangzhou, 510275, China; Institute of Geological Sciences, Oeschger Centre for Climate Change Research, University of Bern, Bern, 3012, Switzerland; School of Earth, Atmospheric and Environmental Sciences, University of Wollongong, Wollongong, NSW 2522, Australia; GFZ German Research Centre for Geosciences, Potsdam, 14473, Germany; Earthquake Administration of Shaanxi Province, Xi'an, 710068, China; School of Geography and Ocean Science, Nanjing University, Nanjing, 210023, China Atmospheric thermodynamics; Sedimentology; Tectonics, Chinese Academy of Sciences; Chinese Loess Plateau; Continental scientific drillings; Different boundary condition; Environmental change; Scientific collaboration; Scientific objectives; Workshop participants, Infill drilling https://www.scopus.com/inward/record.uri?eid=2-s2.0-85097219324&doi=10.5194%2fsd-28-63-2020&partnerID=40&md5=f2b85552ce9b6ed2a059f54c4ad84d20 cited By 4 Z. An P. Zhang H. Vogel Y. Song J. Dodson T. Wiersberg X. Feng H. Lu L. Ai Y. Sun article Ruebsam2020 Article 2020 10.1016/j.epsl.2020.116417 Earth and Planetary Science Letters 546 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85087328494&doi=10.1016%2fj.epsl.2020.116417&partnerID=40&md5=0fab3e07acb09e677790a8c338006b3a Cited by: 32 Wolfgang Ruebsam Grzegorz Pieńkowski Lorenz Schwark article Russell2020 There is a paucity of long and continuous continental records from South East Asia suitable to inform on past changes and underlying causes of the region's climate and associated diverse ecosystem evolution during the late Quaternary. In 2015, the Towuti Drilling Project (TDP) collected a series of sedimentary drill cores from the tectonic, ferruginous, and highly biodiverse Lake Towuti, Sulawesi, one of Indonesia's oldest lakes. The drill cores contain ~1 Myr of uninterrupted lacustrine sedimentation to document long-term environmental and climatic change in the tropical western Pacific, the impacts of geological and environmental changes on the biological evolution of aquatic taxa, and the geomicrobiology and biogeochemistry of metal-rich, ultramafic-hosted lake sediment. Here we use lithostratigraphic, mineralogical, geochemical, and geochronological datasets to elucidate Lake Towuti's tectonic emergence and its biogeochemical responses to climatic and volcanic forcings since lake formation. Our data document that Lake Towuti emerged during a phase of accelerated tectonic subsidence from a landscape characterized by active river channels, shallow lakes and swamps into a permanent lake at ~1 Ma. The lacustrine sediments feature quasi-rhythmic alternations of green organic rich and red sideritic clay beds reflecting changes in lake mixing and biogeochemistry as a response to temperature and hydrological changes driven by orbital-scale changes in insolation and continental ice volume through the mid- to late Pleistocene. Clay deposition is interrupted by two beds of diatomaceous oozes composed primarily of planktonic diatoms that reflect phases of substantially increased primary productivity. The occurrence of these diatomaceous oozes in close association with multiple tephra beds suggests a trophic state change driven by the addition of volcanically sourced P, possibly in combination with a lake mixing state that supports recycling of P. Data on lake age and ontogeny are also in agreement with molecular-clock estimates of ~0.7 Ma (0.18–1.37 Ma) for the divergence of Lake Towuti's Telmatherinid fishes from a riverine ancestor. Our data therefore are compatible with an evolutionary model in which Lake Towuti's endemic fauna is a result of geographic speciation in the Malili Lakes, a set of large lakes in Southeast Sulawesi, driven by physical or chemical dispersal limits imposed by the regional rivers and lakes. More detailed chronological constraints and refined climate and environmental proxy datasets are currently in preparation and will help to paint a more detailed history of the region's climate and environmental history in future studies. © 2020 Elsevier B.V. Article 2020 English 00310182 10.1016/j.palaeo.2020.109905 Palaeogeography, Palaeoclimatology, Palaeoecology 556 Elsevier B.V. Far East; Greater Sunda Islands; Lake Towuti; Malili Lakes; Pacific Ocean; Pacific Ocean (West); South Sulawesi; Sulawesi; Sunda Isles; Bacillariophyta; Pisces; Telmatherinidae; biogeochemistry; climate variation; diatom; dispersal; lacustrine deposit; Pleistocene; Quaternary; speciation (biology); subsidence https://www.scopus.com/inward/record.uri?eid=2-s2.0-85087995636&doi=10.1016%2fj.palaeo.2020.109905&partnerID=40&md5=2a2ce03ed0a0376342b00a48e94c95db Cited by: 8; All Open Access, Green Open Access James M. Russell Satria Bijaksana Alan Deino Abdul Hafidz Doug Haffner Ascelina K.M. Hasberg Marina Morlock Thomas Rintelen Rachel Sheppard Björn Stelbrink Janelle Stevenson article Osinski2020 The origin of the Stac Fada Member has been debated for decades with several early hypotheses being proposed, but all invoking some connection to volcanic activity. In 2008, the discovery of shocked quartz led to the hypothesis that the Stac Fada Member represents part the continuous ejecta blanket of a meteorite impact crater, the location of which was, and remains, unknown. In this paper, we confirm the presence of shock-metamorphosed and-melted material in the Stac Fada Member; however, we also show that its properties are unlike any other confirmed and well documented proximal impact ejecta deposits on Earth. Instead, the properties of the Stac Fada Member are most similar to the Onaping Formation of the Sudbury impact structure (Canada) and impact melt-bearing breccias from the Chicxulub impact structure (Mexico). We thus propose that, like the Sudbury and Chicxulub deposits, Melt Fuel Coolant Interactions – akin to what occur during phreatomagmatic volcanic eruptions – played a fundamental role in the origin of the Stac Fada Member. We conclude that these rocks are not primary impact ejecta but instead were deposited beyond the extent of the continuous ejecta blanket as high-energy ground-hugging sediment gravity flows. © 2020 The Author(s). Published by The Geological Society of London. All rights reserved. 2020 10.1144/jgs2020-056 Journal of the Geological Society 178 Department of Earth Sciences, University of Western Ontario, London, ON N6A 5B7, Canada; Institute for Earth and Space Exploration, University of Western Ontario, London, ON N6A 5B7, Canada; Natural History Museum, Burgring 7, Vienna, A-1010, Austria; Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, AB T6G 2E3, Canada; School of Earth and Environmental Sciences, University of St Andrews, St Andrews, Fife, KY16 9AL, United Kingdom; Department of Earth Sciences, The Natural History Museum, Cromwell Road, London, SW7 5BD, United Kingdom; School of Geographical and Earth Sciences, University of Glasgow, Glasgow, G12 8QQ, United Kingdom 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85100491204&doi=10.1144%2fjgs2020-056&partnerID=40&md5=5d0f02264b99c26fc17b05a45f9788ee cited By 1 G.R. Osinski L. Ferrière P.J.A. Hill A.R. Prave L.J. Preston A. Singleton A.E. Pickersgill article Brüske2020 Article 2020 10.1016/j.precamres.2019.105583 Precambrian Research 338 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85077239124&doi=10.1016%2fj.precamres.2019.105583&partnerID=40&md5=2689ea016fb4f071739a6ca4c45b0919 Cited by: 27 A. Brüske A.N. Martin P. Rammensee S. Eroglu M. Lazarov G. Albut S. Schuth S. Aulbach R. Schoenberg N. Beukes A. Hofmann T. Nägler S. Weyer article Osinski20201121 The conditions, timing, and setting for the origin of life on Earth and whether life exists elsewhere in our solar system and beyond represent some of the most fundamental scientific questions of our time. Although the bombardment of planets and satellites by asteroids and comets has long been viewed as a destructive process that would have presented a barrier to the emergence of life and frustrated or extinguished life, we provide a comprehensive synthesis of data and observations on the beneficial role of impacts in a wide range of prebiotic and biological processes. In the context of previously proposed environments for the origin of life on Earth, we discuss how meteorite impacts can generate both subaerial and submarine hydrothermal vents, abundant hydrothermal-sedimentary settings, and impact analogues for volcanic pumice rafts and splash pools. Impact events can also deliver and/or generate many of the necessary chemical ingredients for life and catalytic substrates such as clays as well. The role that impact cratering plays in fracturing planetary crusts and its effects on deep subsurface habitats for life are also discussed. In summary, we propose that meteorite impact events are a fundamental geobiological process in planetary evolution that played an important role in the origin of life on Earth. We conclude with the recommendation that impact craters should be considered prime sites in the search for evidence of past life on Mars. Furthermore, unlike other geological processes such as volcanism or plate tectonics, impact cratering is ubiquitous on planetary bodies throughout the Universe and is independent of size, composition, and distance from the host star. Impact events thus provide a mechanism with the potential to generate habitable planets, moons, and asteroids throughout the Solar System and beyond. © G.R. Osinski et al., 2020; Published by Mary Ann Liebert, Inc. 2020. 2020 10.1089/ast.2019.2203 Astrobiology 20 1121-1149 Institute for Earth and Space Exploration, University of Western Ontario, London, Canada; Department of Earth Sciences, University of Western Ontario, 1151 Richmond Street, London, ON N6A 5B7, Canada; Uk Centre for Astrobiology, School of Physics and Astronomy, University of Edinburgh, Edinburgh, United Kingdom; Department of Biology, Georgetown University, Washington, DC, United States; Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, United States; Department of Earth Sciences, University of Southern California, Los Angeles, CA, United States 9 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85088226467&doi=10.1089%2fast.2019.2203&partnerID=40&md5=f7f9a825384539b81757ba1231ea024c cited By 34 G.R. Osinski C.S. Cockell A. Pontefract H.M. Sapers article Kleine2020 Surtsey is a young volcanic island in the offshore extension of Iceland's southeast rift zone that grew from the seafloor during explosive and effusive eruptions in 1963–1967. In 1979, a cored borehole (SE-1) was drilled to 181 m depth and in 2017 three cored boreholes (SE-2a, SE-2b and SE-3) were drilled to successively greater depths. The basaltic deposits host a low-temperature (40–141 °C) seawater-dominated geothermal system. Surtsey provides an ideal environment to study water-rock interaction processes in a young seawater geothermal system. Elemental concentrations (SiO2, B, Na, Ca, Mg, F, dissolved inorganic carbon, SO4, Cl) and isotope contents (δD, δ18O) in borehole fluids indicate that associated geothermal waters in submarine deposits originated from seawater modified by reactions with the surrounding basalt. These processes produce authigenic minerals in the basaltic lapilli tuff and a corresponding depletion of certain elements in the residual waters. Coupling of measured and modelled concentrations investigates the effect of temperature and associated abundance of authigenic minerals on chemical fluxes from and to the igneous oceanic crust during low-temperature alteration. The annual chemical fluxes calculated at 50–150 °C range from −0.01 to +0.1 × 1012 mol yr−1 for SiO2, +0.2 to +129 × 1012 mol yr−1 for Ca, −129 to −0.8 × 1012 mol yr−1 for Mg and −21 to +0.4 × 1012 mol yr−1 for SO4 where negative values indicate chemical fluxes from the ocean into the oceanic crust and positive values indicate fluxes from the oceanic crust to the oceans. These flux calculations reveal that water-rock interaction at varying water-rock ratios and temperatures produces authigenic minerals that serve as important sinks of seawater-derived SiO2, Mg and SO4. In contrast, water-rock interaction accompanied by dissolution of basaltic glass and primary crystal fragments provides a significant source of Ca. Such low-temperature alteration could effectively influence the elemental budget of the oceanic igneous crust and ocean waters. The modeling provides insights into water chemistries and chemical fluxes in low-temperature MOR recharge zones. Surtsey also provides a valuable young analogue for assessing the chemical evolution of fluid discharge over the life cycles of seamounts in ridge flank systems. © 2020 Elsevier B.V. 2020 English 00092541 10.1016/j.chemgeo.2020.119702 Chemical Geology 550 Elsevier B.V. Institute of Earth Sciences, University of Iceland, Reykjavík, Iceland; School of Engineering and Natural Sciences, University of Iceland, Reykjavík, Iceland; Iceland GeoSurvey, Reykjavík, Iceland; Department of Geology and Geophysics, University of Utah, Salt Lake City, United States Basalt; Boreholes; Budget control; Deposits; Geothermal fields; Geothermal wells; Infill drilling; Life cycle; Minerals; Offshore oil well production; Seawater; Silica; Silicon; Volcanoes, Authigenic minerals; Dissolved inorganic carbon; Effect of temperature; Effusive eruptions; Elemental concentrations; Low temperature alteration; Water rock interaction process; Water rock interactions, Temperature, analog model; authigenic mineral; chemical alteration; concentration (composition); dissolution; geothermal system; oceanic crust; rift zone; seamount; seawater; volcanic eruption; water-rock interaction, Iceland; Surtsey https://www.scopus.com/inward/record.uri?eid=2-s2.0-85086637414&doi=10.1016%2fj.chemgeo.2020.119702&partnerID=40&md5=803d7fb769821f3fcd7ea736e9048b32 cited By 9 B.I. Kleine A. Stefánsson R. Kjartansdóttir S. Prause T.B. Weisenberger H.I. Reynolds Á.E. Sveinbjörnsdóttir M.D. Jackson M.T. Gudmundsson article Wang2020 We conduct apatite fission-track analysis in the Songliao Basin to reveal the Cenozoic tectonic uplifts and determine how basin development was associated with the transformation from the Paleo-Pacific plate to the Pacific plate and the change of the Pacific plate velocity. Our results from the CCSD-SK1 boreholes in the northern Songliao Basin reveal three Cenozoic cooling (uplift) events:Paleocene (65–50 Ma), Oligocene (33–22 Ma), late Miocene–Pliocene (14–6 Ma) with the apparent mean exhumation rates of 0.08–0.09 mm/yr, 0.08–0.09 mm/yr and 0.11–0.24 mm/yr, respectively. The total removal of the sedimentary cover resulted from 3 cooling (uplift) events is about 1500 m, the removal by the extreme cooling (uplift) event (14–6 Ma) is about 900 m. In this paper, we infer that the transformation of the Paleo-Pacific plate (Izanagi plate) to the Pacific plate plays the first-order control on the first cooling event (65–50 Ma). The second (33–22 Ma) and third (14–6 Ma) cooling events are closely related to the steady and relatively high motion velocity of the Pacific plate. Since Oligocene, a large scale of tectonic uplifts widely happened not only in basins but also in the ranges around them in northeastern China. © 2020 Elsevier Ltd 2020 English 13679120 10.1016/j.jseaes.2020.104353 Journal of Asian Earth Sciences 195 Elsevier Ltd Tianjin Center, China Geological Survey, Tianjin, 300170, China; Key Laboratory of Uranium Geology, China Geological Survey, Tianjin, 300170, China apatite; borehole; Cenozoic; exhumation; fission track dating; historical perspective; plate tectonics; subduction; tectonic evolution, China; Songliao Basin https://www.scopus.com/inward/record.uri?eid=2-s2.0-85082846358&doi=10.1016%2fj.jseaes.2020.104353&partnerID=40&md5=1461f5765b5712c1f747e4a37a201c26 cited By 8 S. Wang Y. Cheng L. Zeng P. Miao R. Jin T. Zhang C. Li X. Zhang article Ebert2020814 The Chicxulub crater (Yucatan Peninsula, Mexico) is considered exceptional in many scientific aspects; morphologically it is the only known impact structure on Earth with a wellpreserved peak ring. Recent drilling (International Ocean Discovery Program-International Continental Scientific Drilling Program Expedition 364) into this topographic feature provides insights into the structural properties and complex formation of a peak ring. By means of U-stage microscopy on shocked quartz grains from the granitic section of the recovered drill core, orientations of feather features (FFs) were determined and local principal axis of stress (σ1) orientations of the shock wave were derived. The FF orientations are strongly confined to a radially outward trend (WNW) relative to the crater center, which emphasizes a link between FF formation and the direction of shock-wave propagation. Thus, FFs represent an excellent tool as a stress-orientation indicator for the shock wave. Our microstructural data set shows that the granitic basement of the peak ring between ~750 and ~1200 m below seafloor behaved as a semi-coherent block above an imbricate thrust zone, and underwent both rotation and local folding during cratering. This validates the block sizes of acoustic fluidization employed in most Chicxulub-scale impact simulations. The folding of the upper part of the granitic basement may have developed by either (1) compression of the crater wall at the transient cavity and/or (2) dragging by the centripetal flow of the overlying crater material. © 2020 Geological Society of America. 2020 10.1130/G47129.1 Geology 48 814-818 Department of Geology, University of Freiburg, Albertstraße 23b, Freiburg, 79104, Germany 8 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85089438030&doi=10.1130%2fG47129.1&partnerID=40&md5=c479ce75d7045d2f280a6cc11bc85173 cited By 5 M. Ebert M.H. Poelchau T. Kenkmann B. Schuster article Friðleifsson2020 The aim of the Iceland Deep Drilling Project is to drill into supercritical geothermal systems and examine their economic potential. The exploratory well IDDP-2 was drilled in the Reykjanes geothermal field in SW Iceland, on the landward extension of the Mid-Atlantic Ridge. The Reykjanes geothermal field produces from a &lt;300 °C reservoir at 1 to 2.5 km depth and is unusual because it is recharged by seawater. The well was cased to 3000 m depth, and then angled towards the main up-flow zone of the system, to a total slant depth of 4659 m (~4500 m vertical depth). Based on alteration mineral assemblages, joint inversion of wireline logging, and rate of heating measurements, the bottom hole temperature is estimated to be about 535 °C. The major problem encountered during drilling was the total loss of circulation below 3 km depth and continuing to the final depth. Drilling continued without recovering drill cuttings, consequently spot coring provided the only deep rock samples from the well. These cores are characteristic of a basaltic sheeted dike complex, with hydrothermal alteration mineral assemblages that range from greenschist to amphibolite facies, hornblende hornfels, and pyroxene hornfels, allowing the opportunity to investigate water-rock interaction in the active roots of an analog of a submarine hydrothermal system. As they have not yet been sampled, the composition of the deep fluids at Reykjanes is unknown at present. Cold water is currently being injected with the aim of enhancing permeability at depth, before allowing the well to heat up prior to flow tests planned for early 2019. The well has at least two fluid feed zones, a dominant one at 3.4 km depth and a second smaller one at 4.5 km. Extensive geophysical surveys of the Reykjanes Peninsula completed recently allow correlation of geophysical signals with rocks properties and in-situ conditions in the subsurface. Earthquake activity monitored with a local seismic network during drilling the IDDP-2 drilling detected abundant small earthquakes (ML ≤ 2) within the depth range of 3–5 km. A zone at 3–5 km depth below the producing geothermal field that was generally aseismic prior to drilling, but became seismically active during the drilling. The drilling of the IDDP-2 has achieved number of scientific and engineering firsts. It is the deepest and hottest drill hole so far sited on an active mid-ocean spreading center. It penetrated an active supercritical hydrothermal environment at depths analogous to those postulated as the high temperature reaction zones feeding black smoker systems. © 2018 Elsevier B.V. 2020 English 03770273 10.1016/j.jvolgeores.2018.08.013 Journal of Volcanology and Geothermal Research 391 Elsevier B.V. HS Orka, Svartsengi, Grindavík, 240, Iceland; Dept. of Earth Sciences, University of California, Riverside, CA 92521, United States; Dept. of Earth and Planetary Sciences, University of California, Davis, CA 95616, United States; Department of Earth Sciences, University of Minnesota, Minneapolis, United States; ÍSOR, Grensásvegur 9, Reykjavík, 108, Iceland; Statoil Research Centre, Trondheim, Norway; Géosciences Montpellier, Université de Montpellier, France; Université de Pau, France; University of Potsdam and GFZ, Potsdam, Germany Clay alteration; Drilling fluids; Earthquakes; Effluent treatment; Geothermal fields; Hydraulic structures; Mineral exploration; Rhenium compounds; Rock drills; Silicate minerals; Smoke; Supercritical fluids, Black smokers; Deep drilling; Geothermal; IDDP; Reykjanes, Infill drilling, amphibolite facies; analog model; black smoker; Deep Sea Drilling Project; drilling; exploration; flow field; geothermal system; greenschist facies; hydrothermal alteration; mineral alteration; spreading center; supercritical flow, Atlantic Ocean; Iceland; Mid-Atlantic Ridge; Reykjanes Peninsula https://www.scopus.com/inward/record.uri?eid=2-s2.0-85053010956&doi=10.1016%2fj.jvolgeores.2018.08.013&partnerID=40&md5=b752b14100c9498cbddf7133a8bbc07d cited By 29 G.Ó. Friðleifsson W.A. Elders R.A. Zierenberg A.P.G. Fowler T.B. Weisenberger K.G. Mesfin Ó. Sigurðsson S. Níelsson G. Einarsson F. Óskarsson E.Á. Guðnason H. Tulinius K. Hokstad G. Benoit F. Nono D. Loggia F. Parat S.B. Cichy D. Escobedo D. Mainprice article Stone2020270 Article 2020 10.11646/phytotaxa.436.3.5 Phytotaxa 436 270 – 282 3 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85086403365&doi=10.11646%2fphytotaxa.436.3.5&partnerID=40&md5=98e65071b636c9287073d179cf1aa56f Cited by: 0 Jeffery R. Stone J. Patrick Kociolek Karlyn S. Westover article Chen2020 Deep sediment cores from long-lived lake basins are fundamental records of paleoenvironmental history, but the power of these reconstructions has been often limited by poor age control. Uranium-thorium (U-Th) dating has the potential to fill a gap in current geochronological tools available for such sediment archives. We present our systematic approach to U-Th date carbonate-rich sediments from the ∼100m drill core from Lake Junín, Peru. The results form the foundation of an age-depth model spanning ∼700 kyrs. High uranium concentrations (0.3–4 ppm) of these sediments allow us to date smaller amounts of material, giving us the opportunity to improve sample selection by avoiding detrital contamination, the greatest factor limiting the success of previous U-Th dating efforts in other lake basins. Despite this advantage, the dates from 174 analyses on 55 bulk carbonate samples reveal significant scatter that cannot be resolved with traditional isochrons, suggesting that at least some of the sediments have not remained closed systems. To understand the source of noise in the geochronological data, we first apply threshold criteria that screen samples by their U/Th ratio, reproducibility, and δ234Uinitial value. We then compare these results with facies types, trace element concentrations, carbonate and total organic carbon content, color reflectance, mineralogy, and ostracode shell color to investigate the causes of open system behavior. Alongside simulations of the isotopic evolution of our samples, we find that the greatest impediment to U-Th dating of these sediments is not detrital contamination, but rather post-depositional remobilization of uranium. Examining U-Th data in these contexts, we identify samples that have likely experienced the least amount of alteration, and use dates from those samples as constraints for the age-depth model. Our work has several lessons for future attempts to U-Th date lake sediments, namely that geologic context is equally as important as the accuracy and precision of analytical measurements. In addition, we caution that significant geologic scatter may remain undetected if not for labor intensive tests of reproducibility achieved through replication. As a result of this work, the deep sediment core from Lake Junín is the only continuous record in the tropical Andes spanning multiple glacial cycles that is constrained entirely by independent radiometric dates. © 2020 Elsevier Ltd 2020 English 02773791 10.1016/j.quascirev.2020.106422 Quaternary Science Reviews 244 Elsevier Ltd Massachusetts Institute of Technology-Woods Hole Oceanographic Institution Joint Program in Oceanography, Cambridge, MA, United States; Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, United States; Department of Geology and Environmental Science, University of Pittsburgh, Pittsburgh, PA, United States; Institut für Geosysteme und Bioindikation, Technische Universität Braunschweig, Braunschweig, Germany; Department of Geological Sciences, University of Florida, Gainesville, FL, United States; College of Earth, Ocean, and Atmospheric Science, Oregon State University, Corvallis, OR, United States; Department of Earth and Environmental Sciences, University of Minnesota Twin Cities, Minneapolis, MN, United States; Institute of Global Environmental Change, Xi'an Jiaotong University, Xi'an, China; State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, China; Pyrenean Institute of Ecology, CSIC, Avda Montañana 1005, Zaragoza, 50059, Spain; Laboratorio Internacional en Cambio Global, CSIC-PUC-UFRJ, Zaragoza, Spain; Department of Earth Sciences, Syracuse University, Syracuse, NY, United States; Instituto Nacional de Investigación en Glaciares y Ecosistemas de Montañas, Huaraz, Ancash, Peru; Department of Geology, Union College, Schenectady, NY, United States Binary alloys; Carbonation; Core drilling; Geochronology; Lake pollution; Lakes; Minerals; Organic carbon; Sediments; Thorium compounds; Trace elements; Uranium alloys, Accuracy and precision; Color reflectance; Radiometric dates; Reproducibilities; System behaviors; Total organic carbon content; Trace element concentrations; Uranium concentration, Thorium alloys, biostratigraphy; color; core analysis; facies analysis; geochronology; lacustrine deposit; ostracod; paleoenvironment; remobilization; shell; total organic carbon; trace element; uranium series dating, Junin; Lake Junin; Peru, Ostracoda https://www.scopus.com/inward/record.uri?eid=2-s2.0-85089419593&doi=10.1016%2fj.quascirev.2020.106422&partnerID=40&md5=03bf80d83c88dc3d445e71e2602bd88d cited By 7 C.Y. Chen D. McGee A. Woods L. Pérez R.G. Hatfield R.L. Edwards H. Cheng B.L. Valero-Garcés S.B. Lehmann J.S. Stoner A. Schwalb I. Tal G.O. Seltzer P.M. Tapia M.B. Abbott D.T. Rodbell article beinlich2020ultramafic The occurrence of the quartz-carbonate alteration assemblage (listvenite) in ophiolites indicates that ultramafic rock represents an effective sink for dissolved CO2. However, the majority of earlier studies of ultramafic rock carbonation had to rely on the surface exposure of reaction textures and field relationships. Here we present the first observations on ultramafic rock alteration obtained from the 300 m deep BT1B drill hole, ICDP Oman Drilling Project, allowing for a continuous and high-resolution investigation. Hole BT1B recovered continuous drill core intersecting surface alluvium, 200 m of altered ultramafic rock comprising mainly listvenite and minor serpentinite bands at 90 and 180 m depth, and 100 m of the underlying metamorphic sole. Textural evidence suggests that the carbonation of fully serpentinized harzburgite commenced by non-equilibrium growth of spheroidal carbonate characterized by sectorial zoning resulting from radially oriented low-angle boundaries. In the serpentinite, carbonate spheroids are composed of alternating magnesite cores and dolomite rims, whereas texturally similar carbonate in the listvenite is composed of Fe-rich magnesite cores and Ca-Fe-rich magnesite rims. The distinct compositions and mineral inclusions indicate that the carbonation extent was controlled by fluid accessibility resulting in the simultaneous formation of limited carbonate in the serpentinite bands and complete carbonation in the listvenite parts of BT1B. The presence of euhedral magnesite overgrowing spheroidal carbonate in the listvenite suggests near-equilibrium conditions during the final stage of carbonation. The carbonate clumped isotope thermometry constrains carbonate crystallization between 50 °C and 250 °C, implying repeated infiltration of reactive fluids during ophiolite uplift and cooling. ©2020. The Authors. 2020 English 21699313 10.1029/2019JB019060 Journal of Geophysical Research: Solid Earth 125 Wiley Online Library e2019JB019060 Department of Earth Science, University of Bergen, Bergen, Norway; Department of Earth Sciences, Utrecht University, Utrecht, Netherlands; Institute of Earth Sciences, Academia Sinica, Taipei, Taiwan; Institute of Geology and Geoinformation, Geological Survey of Japan, The National Institute of Advanced Industrial Science and Technology, Ibaraki, Japan; Géosciences Montpellier, Université Montpellier, Montpellier, France; Lamont–Doherty Earth Observatory, Columbia University, Palisades, NY, United States 6 carbonate rock; chemical alteration; crystallization; geothermometry; ophiolite; texture; ultramafic rock, Oman https://www.scopus.com/inward/record.uri?eid=2-s2.0-85086498143&doi=10.1029%2f2019JB019060&partnerID=40&md5=1c04d8d80dd248467a8182d06c818b80 cited By 24 Andreas Beinlich Oliver Plümper Esmée Boter Inigo A Müller Fatma Kourim Martin Ziegler Yumiko Harigane Romain Lafay Peter B Kelemen Oman Drilling Project Science Team article Lu2020 With the development of deep energy resources, understanding variations in the physical and mechanical properties of rocks at different depths is significant. In this paper, core samples from ten different burial depths (1000 m, 1300 m, 1600 m, 1850 m, 2600 m, 3500 m, 4800 m, 5100 m, 5600 m, and 6400 m) were collected from the Songke No. 2 (SK-2) well and the Daqing Oilfield. To the best of our knowledge, this is the first study involving the physical property and uniaxial compression testing of rock cores from such a large range of burial depths. The experimental results show that the content of weak phase minerals decreases with increasing depth. The change in the hard phase minerals varies nonlinearly with depth. From 3500 to 5600 m, the content of hard phase minerals decreases, while the content of the middle phase minerals increases. The elastic modulus exponentially increases with increasing depth, while Poisson’s ratio decreases with increasing depth. Additionally, the uniaxial compressive strength displays a nonlinear logarithmic increase with increasing depth. Finally, the effects of petrophysical properties on the mechanical behavior of rock at different depths are discussed. The elastic modulus, Poisson’s ratio, and compressive strength all have a negative correlation with the content of weak phase minerals. These results have important value for studying the mechanics of rocks at different depths. © 2020, Springer Nature Switzerland AG. 2020 English 23638419 10.1007/s40948-020-00163-z Geomechanics and Geophysics for Geo-Energy and Geo-Resources 6 Springer Science and Business Media Deutschland GmbH Guangdong Provincial Key Laboratory of Deep Earth Sciences and Geothermal Energy Exploitation and Utilization, Institute of Deep Earth Sciences and Green Energy, College of Civil and Transportation Engineering, Shenzhen University, Shenzhen, 51806, China; Shenzhen Key Laboratory of Deep Underground Engineering Sciences and Green Energy, Shenzhen University, Shenzhen, 518060, China; MOE Key Laboratory of Deep Earth Science and Engineering, Sichuan University, Chengdu, 610065, China 3 Compression testing; Elastic moduli; Energy resources; Minerals; Petrophysics; Rocks, Daqing oilfields; Important value; Mechanical behavior; Negative correlation; Petrophysical properties; Physical and mechanical properties; Uniaxial compression testing; Uniaxial compressive strength, Compressive strength https://www.scopus.com/inward/record.uri?eid=2-s2.0-85087032199&doi=10.1007%2fs40948-020-00163-z&partnerID=40&md5=0269a3b61875d7dcdd27d538e27067c7 cited By 13 Y. Lu C. Li Z. He M. Gao R. Zhang H. Xie article Vuillemin20201955 Ferruginous lacustrine systems, such as Lake Towuti, Indonesia, are characterized by a specific type of phosphorus cycling in which hydrous ferric iron (oxyhydr) oxides trap and precipitate phosphorus to the sediment, which reduces its bioavailability in the water column and thereby restricts primary production. The oceans were also ferruginous during the Archean, thus understanding the dynamics of phosphorus in modern-day ferruginous analogues may shed light on the marine biogeochemical cycling that dominated much of Earth’s history. Here we report the presence of large crystals ( > 5 mm) and nodules (> 5 cm) of vivianite – a ferrous iron phosphate – in sediment cores from Lake Towuti and address the processes of vivianite formation, phosphorus retention by iron and the related mineral transformations during early diagenesis in ferruginous sediments. Core scan imaging, together with analyses of bulk sediment and pore water geochemistry, document a 30m long interval consisting of sideritic and non-sideritic clayey beds and diatomaceous oozes containing vivianites. Highresolution imaging of vivianite revealed continuous growth of crystals from tabular to rosette habits that eventually form large (up to 7 cm) vivianite nodules in the sediment. Mineral inclusions like millerite and siderite reflect diagenetic mineral formation antecedent to the one of vivianite that is related to microbial reduction of iron and sulfate. Together with the pore water profiles, these data suggest that the precipitation of millerite, siderite and vivianite in soft ferruginous sediments stems from the progressive consumption of dissolved terminal electron acceptors and the typical evolution of pore water geochemistry during diagenesis. Based on solute concentrations and modeled mineral saturation indices, we inferred vivianite formation to initiate around 20m depth in the sediment. Negative 56Fe values of vivianite indicated incorporation of kinetically fractionated light Fe2C into the crystals, likely derived from active reduction and dissolution of ferric oxides and transient ferrous phases during early diagenesis. The size and growth history of the nodules indicate that, after formation, continued growth of vivianite crystals constitutes a sink for P during burial, resulting in long-term P sequestration in ferruginous sediment. © Author(s) 2020. This work is distributed under the Creative Commons Attribution 4.0 License. Article 2020 English 17264170 10.5194/bg-17-1955-2020 Biogeosciences 17 Copernicus GmbH 1955 – 1973 7 Greater Sunda Islands; Lake Towuti; Malili Lakes; South Sulawesi; Sulawesi; Sunda Isles; diagenesis; electron; geochemistry; iron oxide; phosphate; phosphorus; porewater; saturation; sediment analysis; siderite; vivianite; water column https://www.scopus.com/inward/record.uri?eid=2-s2.0-85083457042&doi=10.5194%2fbg-17-1955-2020&partnerID=40&md5=d15dddd5415f1948dde1ece4c0385f52 Cited by: 15; All Open Access, Gold Open Access, Green Open Access Aurèle Vuillemin André Friese Richard Wirth Jan A. Schuessler Anja M. Schleicher Helga Kemnitz Andreas Lücke Kohen W. Bauer Sulung Nomosatryo Friedhelm Von Blanckenburg Rachel Simister Luis G. Ordoñez Daniel Ariztegui Cynthia Henny James M. Russell Satria Bijaksana Hendrik Vogel Sean A. Crowe Jens Kallmeyer article Koepke202021 The Oman ophiolite is regarded as best proxy for accreted oceanic crust from typical fast-spreading ridge systems on land. However, the Oman ophiolite is influenced by initial subduction zone initiation, and the nature of the details of the subduction zone setting is still under controversial debate. While a first magmatic phase shows features of magmatic accretion very similar to those known from the East Pacific Rise, except that the primary melts were slightly water-enriched, a second type of magmatism is characterized by an apparent subduction-zone related imprint, producing rocks like FAB basalts and boninites in the upper crust, as well as cross-cutting gabbronorites and wehrlites in the deeper crust. In this paper, we apply diverse experimental studies in wet tholeiitic and peridotitic systems performed at lower pressures (100 to 500 MPa) in the experimental lab of the University Hannover, in order to constrain the details of the magmatic processes proceeded at the Oman ophiolite paleoridge during the Cretaceous, with special focus on the influence of water on the phase stabilities and phase relations. The experiments were performed in vertically oriented internally heated pressure vessels (IHPV) (see Berndt et al., 2002; Fig. 1). This facility uses as pressure medium mixtures of Ar and H2 in order to adjust the required fH2 in the vessel, enabling us to control the redox conditions. The fH2 prevailing in the IHPV at high P and T was measured with a Shaw-membrane made of platinum. The overall variation in fO2 in all experimental series was in the range between ∼FMQ-1 and ∼FMQ+3.2, thus covering the range of oxygen fugacities prevailing in natural MORB magmas (Bezos and Humler, 2005). For understanding the magmatic processes during the Oman ophiolite paleoridge accretion, transects through the lower (GT1) and middle (GT2) crust have been drilled in the frame of ICDP (International Continental Scientific Drilling Program). Drill sites have been selected in the Wadi Tayin massif, which is known that the influence of magmatic phase 2 characterized by subduction-related primary melts is minimal. Details and progress obtained in the Oman Drilling Project (OmanDP) can be found here: (https://www.omandrilling.ac.uk/). Regarding the first magmatic phase of the processes at the Oman ophiolite paleoridge, a characteristic observation made during the description of the drilled cores GT1 (lower crust) and GT2 (mid-curst) was that quite often layers in the layered gabbro series occur which show the presence of clinopyroxene joining olivine instead of plagioclase (under near liquidus conditions). In terms of lithologies this could be interpreted as presence of wehrlitic crystal mushes as early cumulates instead of troctolitic, which are the typical ones for primary magmatism at typical fast-spreading ridges. This situation could be experimentally simulated by adding a moderate to high water activity to primitive MORB at pressures ≥ 200 MPa, resulting in a shift of the clinopyroxene-in curve to higher temperatures above the plagioclase-in curve (Feig et al. 2006; see Fig. 2). Regarding the second, late-stage magmatic phase, the formation of typical Oman high-Ca-boninites could be experimentally simulated by water-saturated partial melting of Oman harzburgite at 200 MPa and relatively low temperatures between 1100 and 1200°C. Depleted gabbronorites crosscutting layered gabbros of phase 1 magmatism can be regarded as cumulates formed in these boninitic melts. Late wehrlites crosscutting layered gabbro could be produced by accumulation of olivine and clinopyroxene at temperatures between 1040 and 1080°C in a hydrous gabbroic system at pressures &gt; 100 MPa with bulk water content of 2–3 wt%. © 2020 Geological Society of China 2020 English 10009515 10.1111/1755-6724.14439 Acta Geologica Sinica (English Edition) 94 John Wiley and Sons Inc 21-22 Leibniz University Hannover, Hannover, 30167, Germany; University of Tasmania, Hobart, TAS 700, Australia accretion; clinopyroxene; gabbro; geoaccumulation; harzburgite; magmatism; mid-ocean ridge basalt; olivine; ophiolite; partial melting; plagioclase; subduction zone; water content, Arabian Sea; East Pacific Rise; Germany; Gulf of Oman; Hannover; Indian Ocean; Lower Saxony; Pacific Ocean https://www.scopus.com/inward/record.uri?eid=2-s2.0-85095811722&doi=10.1111%2f1755-6724.14439&partnerID=40&md5=0166fe90cac564fbc1959356da340526 cited By 0 J. Koepke S.T. Feig article Whalen2020 The Chicxulub impact led to the formation of a ~ 200-km wide by ~1-km deep crater on México's Yucatán Peninsula. Over a period of hours after the impact the ocean re-entered and covered the impact basin beneath several hundred meters of water. A suite of impactites were deposited across the crater during crater formation, and by the resurge, tsunami and seiche events that followed. International Ocean Discovery Program/International Continental Scientific Drilling Program Expedition 364 drilled into the peak ring of the Chicxulub crater, and recovered ~130 m of impact deposits and a 75-cm thick, fine-grained, carbonate-rich “Transitional Unit”, above which normal marine sedimentation resumed. Here, we describe the results of analyses of the uppermost impact breccia (suevite) and the Transitional Unit, which suggests a gradual waning of energy recorded by this local K-Pg boundary sequence. The dominant depositional motif in the upper suevite and the Transitional Unit is of rapid sedimentation characterized by graded bedding, local cross bedding, and evidence of oscillatory currents. The lower Transitional Unit records the change from deposition of dominantly sand-sized to mainly silt to clay sized material with impact debris that decreases in both grain size and abundance upward. The middle part of the Transitional Unit is interrupted by a 20 cm thick soft sediment slump overlain by graded and oscillatory current cross-laminated beds. The uppermost Transitional Unit is also soft sediment deformed, contains trace fossils, and an increasing abundance of planktic foraminifer and calcareous nannoplankton survivors. The Transitional Unit, as with similar deposits in other marine target impact craters, records the final phases of impact-related sedimentation prior to resumption of normal marine conditions. Petrographic and stable isotopic analyses of carbon from organic matter provide insight into post-impact processes. δ13Corg values are between terrestrial and marine end members with fluctuations of 1–3‰. Timing of deposition of the Transitional Unit is complicated to ascertain. The repetitive normally graded laminae, both below and above the soft sediment deformed interval, record rapid deposition from currents driven by tsunami and seiches, processes that likely operated for weeks to potentially years post-impact due to subsequent continental margin collapse events. Highly siderophile element-enrichment at the top of the unit is likely from fine-grained ejecta that circulated in the atmosphere for several years prior to settling. The Transitional Unit is thus an exquisite record of the final phases of impact-related sedimentation related to one of the most consequential events in Earth history. © 2020 The Authors 2020 10.1016/j.margeo.2020.106368 Marine Geology 430 Dept. of Geosciences and Geophysical Institute, University of Alaska Fairbanks, Fairbanks, AK 99775, United States; Institute for Geophysics, Jackson School of Geosciences, University of Texas at Austin, Austin, TX 78758, United States; Department of Geological Sciences, Jackson School of Geosciences, University of Texas at Austin, Austin, TX 79712, United States; Center for Planetary Systems Habitability, University of Texas at Austin, Austin, TX 79712, United States; Department of Geosciences, Pennsylvania State University, University ParkPA 16801, United States; Department of Earth Science and Engineering, Imperial College London, London, SW7 2AZ, United Kingdom; Western Australian Organic and Isotope Geochemistry Centre, The Institute for Geoscience Research, School of Earth and Planetary Science, Curtin University, Perth, WA 6102, Australia; Faculty of Earth and Life Sciences (FALW), Vrije Universiteit Amsterdam, Amsterdam, 1081 HV, Netherlands; Centro de Astrobiología Instituto Nacional de Técnica Aeroespacial-Spanish National Research Council (INTA-CSIC), Instituto Nacional de Técnica Aeroespacial, Torrejon de Ardoz, 28850, Spain; Eyring Materials Center, Arizona State University, Tempe, AZ 85287-1704, United States; Lunar and Planetary Institute, Houston, TX 77058, United States; Analytical, Environmental and Geo-Chemistry, Vrije Universiteit Brussel, Brussels, Belgium https://www.scopus.com/inward/record.uri?eid=2-s2.0-85095704506&doi=10.1016%2fj.margeo.2020.106368&partnerID=40&md5=9062d5371f10f30888417b6040880eb2 cited By 14 M.T. Whalen S.P.S. Gulick C.M. Lowery T.J. Bralower J.V. Morgan K. Grice B. Schaefer J. Smit J. Ormö A. Wittmann D.A. Kring S. Lyons S. Goderis article Pham-Duc2020 Lake Chad, in the Sahelian zone of west-central Africa, provides food and water to ~50 million people and supports unique ecosystems and biodiversity. In the past decades, it became a symbol of current climate change, held up by its dramatic shrinkage in the 1980s. Despites a partial recovery in response to increased Sahelian precipitation in the 1990s, Lake Chad is still facing major threats and its contemporary variability under climate change remains highly uncertain. Here, using a new multi-satellite approach, we show that Lake Chad extent has remained stable during the last two decades, despite a slight decrease of its northern pool. Moreover, since the 2000s, groundwater, which contributes to ~70% of Lake Chad’s annual water storage change, is increasing due to water supply provided by its two main tributaries. Our results indicate that in tandem with groundwater and tropical origin of water supply, over the last two decades, Lake Chad is not shrinking and recovers seasonally its surface water extent and volume. This study provides a robust regional understanding of current hydrology and changes in the Lake Chad region, giving a basis for developing future climate adaptation strategies. © 2020, The Author(s). Article 2020 English 20452322 10.1038/s41598-020-62417-w Scientific Reports 10 Nature Research 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85082562160&doi=10.1038%2fs41598-020-62417-w&partnerID=40&md5=36563ed706c73e8cacfa5f72addc146e Cited by: 38; All Open Access, Gold Open Access, Green Open Access Binh Pham-Duc Florence Sylvestre Fabrice Papa Frédéric Frappart Camille Bouchez Jean-Francois Crétaux article Stein2020 2020 English 02773791 10.1016/j.quascirev.2020.106639 Quaternary Science Reviews 249 Elsevier Ltd Institute of Earth Sciences, The Hebrew University, Givat Ram, Jerusalem, 91904, Israel; Geological Survey of Israel, 32, Yesha'yahu Leibowitz, Street, Jerusalem, 95501, Israel; Lamont-Doherty Earth Observatory of Columbia University, 61 Route 9W, Palisades, NY 10964, United States; Department of Earth and Environmental Sciences, Columbia University, 61 Route 9W, Palisades, NY 10964, United States deep drilling; deep sea; maintenance; paleoenvironment; reconstruction https://www.scopus.com/inward/record.uri?eid=2-s2.0-85092914567&doi=10.1016%2fj.quascirev.2020.106639&partnerID=40&md5=cbd580cad6442bbb61ad887898151296 cited By 2 M. Stein S.L. Goldstein article An202063 The Weihe Basin, enclosed by the Chinese Loess Plateau to the north and the Qinling Mountains to the south, is an outstanding, world-class continental site for obtaining high-resolution multi-proxy records that reflect environmental changes spanning most of the Cenozoic. Previous geophysical and sedimentary studies indicate that the basin hosts 6000-8000 m thick fluvial-lacustrine sedimentary successions spanning the Eocene to Holocene. This sedimentary record provides an excellent and unique archive to decipher long-term tectonic-climate interactions related to the uplift of the Tibetan Plateau, the onset/evolution of the Asian monsoon, and the development of the biogeography of East Asia. Owing to its location at the interface of the opposing westerly and Asian monsoon circulation systems, the Weihe Basin also holds enormous promise for providing a record of changes in these circulation systems in response to very different boundary conditions since the Eocene. To develop an international scientific drilling programme in the Weihe Basin, the Institute of Earth Environment, Chinese Academy of Sciences, organized a dedicated workshop with 55 participants from eight countries. The workshop was held in Xi'an, China, from 15 to 18 October 2019. Workshop participants conceived the key scientific objectives of the envisaged Weihe Basin Drilling Project (WBDP) and discussed technical and logistical aspects as well as the scope of the scientific collaboration in preparation for a full drilling proposal for submission to the International Continental Scientific Drilling Program (ICDP). Workshop participants mutually agreed to design a two-phase scientific drilling programme that will in a first phase target the upper 3000 m and in a second phase the entire up to 7500 m thick sedimentary infill of the basin. For the purpose of the 7500 m deep borehole, the world's only drill rig for ultra-deep scientific drilling on land, Crust 1, which previously recovered the entire continental Cretaceous sediments in the Songliao Basin, will be deployed in the WBDP. © 2020 Copernicus GmbH. All rights reserved. 2020 English 18168957 10.5194/sd-28-63-2020 Scientific Drilling 28 Copernicus GmbH 63-73 State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, 710061, China; CAS Center for Excellence in Quaternary Science and Global Change, Xi'an, 710061, China; School of Earth Sciences and Engineering, Sun Yat-Sen University, Guangzhou, 510275, China; Institute of Geological Sciences, Oeschger Centre for Climate Change Research, University of Bern, Bern, 3012, Switzerland; School of Earth, Atmospheric and Environmental Sciences, University of Wollongong, Wollongong, NSW 2522, Australia; GFZ German Research Centre for Geosciences, Potsdam, 14473, Germany; Earthquake Administration of Shaanxi Province, Xi'an, 710068, China; School of Geography and Ocean Science, Nanjing University, Nanjing, 210023, China Atmospheric thermodynamics; Sedimentology; Tectonics, Chinese Academy of Sciences; Chinese Loess Plateau; Continental scientific drillings; Different boundary condition; Environmental change; Scientific collaboration; Scientific objectives; Workshop participants, Infill drilling https://www.scopus.com/inward/record.uri?eid=2-s2.0-85097219324&doi=10.5194%2fsd-28-63-2020&partnerID=40&md5=f2b85552ce9b6ed2a059f54c4ad84d20 cited By 4 Z. An P. Zhang H. Vogel Y. Song J. Dodson T. Wiersberg X. Feng H. Lu L. Ai Y. Sun article Hatfield202083 Sediment records from deep-drilling projects such as those carried out by the International Continental Scientific Drilling Program are often tens to hundreds of meters in length. To ensure the complete recovery of a stratigraphic section, a basin is usually cored multiple times in adjacent holes so that gaps between sequential cores, poorly recovered sections, or intervals affected by disturbance can be bridged or replaced with sediments from another hole. Stratigraphic correlation, the alignment of stratigraphically-equivalent horizons in cores from different holes in a common-depth scale, and splice generation, the integration of the most-representative core sections into a composite-stratigraphic section, are essential steps in this process to both evaluate and synthesize the recovered-sediment record and focus the scientific analyses. However, these undertakings can be complex and are inherently subjective, making the need for the development of a single robust stratigraphic section early in the project critical to its success. Despite this, the steps between core recovery and on-splice data generation are rarely published in sufficient detail to allow reconstruction, or refinement, of the composited record at a later date. To increase the transparency of how the composite record is created, and to provide a template for future projects, we detail the step-by-step approaches and decisions involved in generating the composite-depth scale and complete-stratigraphic splice following recovery of sediments from Lake Junín, Peru. We first explain the details and nuances of different drilling-depth scales before describing how we integrated different physical property records to generate the composite-depth scale and complete-stratigraphic splice. Here, we show that due to the complex stratigraphy in the Lake Junín sediments, high-resolution line-scan images of the cores offer millimeter-scale precision for construction of the primary-stratigraphic splice at a resolution not afforded by other physical property data. Finally, through comparison of the spliced record to physical-property records acquired in situ on the borehole, we demonstrate that the stratigraphic splice is an accurate representation of the sediment accumulated in the Lake Junín basin. © 2019, Springer Nature B.V. 2020 English 09212728 10.1007/s10933-019-00098-w Journal of Paleolimnology 63 Springer 83-100 College of Earth, Ocean, and Atmospheric Science, Oregon State University, Corvallis, OR 97330, United States; Department of Geological Sciences, University of Florida, Gainesville, FL 32611, United States; Geology and Environmental Science, University of Pittsburgh, Pittsburgh, PA 15260, United States; Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, United States; Helmholtz-Zentrum Potsdam, Deutsches GeoForschungsZentrum GFZ, Potsdam, Germany; Department of Geology, Union College, Schenectady, NY 12308, United States 1 deep drilling; historical record; lacustrine deposit; physical property; project assessment; reconstruction; recovery; scale effect; sediment core; stratigraphic correlation, Junin; Lake Junin; Peru https://www.scopus.com/inward/record.uri?eid=2-s2.0-85075369507&doi=10.1007%2fs10933-019-00098-w&partnerID=40&md5=fc4915b3e04a5b213b7a99d877d576df cited By 9 R.G. Hatfield A. Woods S.B. Lehmann N. Weidhaas C.Y. Chen S. Pierdominici J.S. Stoner M.B. Abbott D.T. Rodbell article Fu20202135 Denglouku Formation in Xujiaweizi area is an important field needing urgent breakthroughs for deep gas exploration in northern Songliao Basin. In order to clarify the distribution characteristics of sedimentary facies of Denglouku Formation in Xujiaweizi area, the isochronal framework is established and the sedimentary facies is comprehensively analyzed, by core observation of sedimentary facies, sedimentary cycle analysis by logging data and comprehensive analysis of seismic attribute slices. The results show that: The Denglouku Formation in Xujiaweizi area mainly develops 6 sedimentary facies from bottom to top, the alluvial fan and fan delta, the lake and braided river delta, the river and lake pan-plane, 10 sedimentary subfacies and 20 sedimentary microfacies. Vertically, the development of sedimentary system in the first member of Denglouku Formation is limited, which controlled by unconformity. The sedimentary facies system of Denglouku Formation is alluvial fan-fan delta-lake sedimentary system in the first member, braided river delta-intermittent lake depositional system in the second-third member, and fluvial sedimentary system in the fourth member. The fan delta front glutenite, braided delta distributary channel coarse sandstone and braided channel thick sandstone provide favorable reservoir space for gas accumulation. Accurate identification of fine sedimentary facies of Denglouku Formation in Xujiaweizi area provides an important basis for further exploration and deployment, and has positive exploration significance. © 2020, Springer Nature Singapore Pte Ltd. 2020 English 9789811524844 18668755 10.1007/978-981-15-2485-1_194 Springer Series in Geomechanics and Geoengineering Springer Lin J. 2135-2148 Exploration and Development, Research Institute of Daqing Oilfield Co Ltd., Daqing, 163712, China Deposition; Lakes; Petroleum prospecting; Rivers; Sandstone, Braided river deltas; Comprehensive analysis; Denglouku formations; Depositional system; Distributary channels; Distribution characteristics; Sedimentary micro-facies; Sedimentary systems, Sedimentology, alluvial fan; depositional environment; facies; fan delta; gas field; hydrocarbon exploration; seismic data; spatial distribution; unconformity; well logging, China; Heilongjiang; Songliao Basin; Xujiaweizi https://www.scopus.com/inward/record.uri?eid=2-s2.0-85088894808&doi=10.1007%2f978-981-15-2485-1_194&partnerID=40&md5=61dc2aec12800430abc4dbbf23a74431 cited By 0 X.-L. Fu Z.-W. Huo J. Wang K.-N. Cui M.-Y. Jin Z.-M. Zhu X.-J. Bai H. Liu B. Yue article Salguero-Hernández2020627 Chicxulub crater formed ~ 66 Ma ago by an asteroid impact on the Yucatan platform in the southern Gulf of Mexico. The crater has a ~ 200 km rim diameter and has been covered by carbonate sediments up to ~ 1.1 km thick in the central zone. Previous studies have identified the structure and major crater units through geophysical models from seismic reflection and potential field data, classified as the central uplift, terrace zone, outer and inner ring fault zones and impactite deposits. Impact produced a deep excavation cavity, with fragmentation and ejection of large volumes of crustal target rocks. Understanding the pre-existing structures, impact-induced deformation and post-impact processes requires high-resolution images of the crater and target zone. For this study, we use complex trace attributes of instantaneous phase, frequency, envelope amplitude and similarity, in an E-W seismic reflection profile crossing the crater in the marine sector. Geophysical logs and borehole lithological columns from the on-land drilling projects are used to constrain the petrophysical analysis. Seismic attributes aid to characterize the radial fault zones and physical property contrasts, revealing asymmetries in the crater structure. The reflector packages in the post-impact sediments and target Cretaceous sequence are identified in the frequency and phase attributes. The bottom crater reflectors, with the basal sediments filling the crater floor topography, are enhanced with the envelope amplitude attribute. A set of high-amplitude reflectors is shown in the similarity attribute, in which the reflector geometry is delineated on the target carbonate sequence. The offsets in the high-amplitude reflectors between the eastern and western sectors are possibly associated to target pre-impact asymmetries, impact deformation and effects of central crater collapse. © 2020, Institute of Geophysics, Polish Academy of Sciences & Polish Academy of Sciences. 2020 10.1007/s11600-020-00442-z Acta Geophysica 68 627-640 Facultad de Ingeniería, Universidad Autónoma del Carmen, Ciudad del Carmen, Campeche 24180, Mexico; Programa Universitario de Perforaciones en Océanos y Continentes, Instituto de Geofísica, Universidad Nacional Autónoma de México, Ciudad Universitaria, México, 04510, Mexico; Coordinación de Plataformas Oceanográficas, Coordinación de la Investigación Científica, Universidad Nacional Autónoma de México, Ciudad Universitaria, México, 04510, Mexico; Instituto de Investigación Científica y Estudios Avanzados Chicxulub, Parque Científico y Tecnológico de Yucatán, Sierra Papacal, Mérida, Yucatán 97302, Mexico 3 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85085291034&doi=10.1007%2fs11600-020-00442-z&partnerID=40&md5=402dc453e354caa5cea6d9ca96aa1d81 cited By 2 E. Salguero-Hernández L. Pérez-Cruz J. Urrutia-Fucugauchi conference Batir2020504 The Snake River Plain (SRP) terrestrial heat flow and subsurface thermal regime are not well understood but are important for assessing the local geothermal resource potential, both for conventional and for Enhanced Geothermal Systems (EGS) development in the region. Resource evaluation for the SRP is complicated by the disparate data density, along with the known lateral advection of heat in the Eastern Snake River Plain Aquifer and vertical heat transport by fluids in the bounding faults, primarily in the southwestern section. Fortunately, recent studies, e.g., the Snake River Plain Play Fairway Analysis, the Idaho FORGE site, and site-specific investigations, which included drilling within the Camas Prairie and on the Mountain Home Air Force Base, near Twin Falls, and in the Eastern Snake River Plain as part of the HOTSPOT Project, add both additional drilling and geophysical data. The SMU Geothermal Laboratory has conducted detailed studies of SRP tectonics and heat flow since the 1970's and used this knowledge as part of the EGS geothermal potential estimation for the conterminous United States in 2006 and again in 2011, calculating geothermal potential from 3.5 km to 10 km depth. Recent temperature modeling refined the calculation methodology to estimate shallow (1 km to 4 km) resource potential using an improved thermal conductivity model and incorporation of shallow groundwater flow. By incorporating the new SRP geology, geophysics, and 206 thermal data sites into the SMU thermal modeling methodology, this project updates the resource estimate for the SRP, and generates new temperature-at-depth maps for the shallow subsurface (1 km to 4 km). The project results highlight the EGS potential resource areas (≥150°C) and areas with more exploration risks based on minimal and/or low-quality data. The newest temperature modeling results suggest EGS potential is near five times greater in the SRP than previously estimated. © 2020 Geothermal Resources Council. All rights reserved. 2020 English 9781713822097 01935933 Transactions - Geothermal Resources Council 44 Geothermal Resources Council 504-534 Roy M. Huffington Department of Earth Sciences, Southern Methodist University, Dallas, TX, United States; National Renewable Energy Laboratory, Golden, CO, United States; Columbia Geoscience, Portland, OR, United States Aquifers; Geothermal fields; Geothermal prospecting; Geothermal wells; Groundwater flow; Heat transfer; Infill drilling; Landforms; Rivers; Thermal conductivity, Additional drillings; Enhanced geothermal systems; Geothermal potential; Geothermal resources; Subsurface thermal regime; Temperature modeling; Terrestrial heat flow; Thermal conductivity model, Groundwater resources https://www.scopus.com/inward/record.uri?eid=2-s2.0-85103451958&partnerID=40&md5=e5ece3938e5e78b51b65c095907e9822 cited By 1 J. Batir M. Richards M. Hornbach D. Blackwell A. Kolker A. Waibel article González-Flores2020 The shallow structures of the Chalco and Xochimilco sub-basins (southeastern Mexico Basin) are established based on a seismic line that stretches trough both depressions. Interpretation of the seismic line was constraint by the stratigraphic column cut by the approximately 3000 m deep Tulyehualco well. The seismic line was converted to depth based on a vertical transverse isotropy velocity model determined from the interval, and root mean square (rms) velocities of the geologic units as established at the Tulyehualco deep well. P-wave modelling confirmed the results. The volcano-sedimentary infill established is consistent with the stratigraphic column of the 502 m deep MexiDrill borehole. It was possible to establish 1) the base of the fine stratified lacustrine sediments, and 2) the top of the basalts along the Xochimilco and Chalco sub-basins. The Xochimilco and Chalco sub-basins are separated by a shallow structural high (interpreted as due volcanic flows) against which the lacustrine sediments abut. A conspicuous anticline shaped structural high (adjacent to Xico tuff ring) divides the Chalco sub-basin into two depressions. The top of the basaltic basement matches with the upper volcanic unit horizon. In the western trough, the basement gets deeper from east to west (from 336 m at the structural high, to 660 m to the west). Immediately east of the anticline-shaped structural high, the basement is located at 510 m. Beneath the Xochimilco trough (at 180 m approximately) the volcanic basement shallows up smoothly northwestwards. In the eastern part of the Xochimilco sub-basin, the shallow lacustrian sediments are relatively thin. Northwestwards of the Tulyehualco well, their thickness diminishes. This apparent thinning is accounted by the fact that there the seismic line occupies the northern rim of the depression. Reflections in the upper 300 m of the section are not continuous. Beneath the central part of Chalco lake the reflectors are horizontal with a slight westward dip. At both sides of this central zone, reflectors are inclined or have dome shapes. This indicates that deposition along the Chalco sub-basin has been deformed. The thickness of the reflections associated with the fine laminated to volcanoclastic material transition zone is approximately constant, but thins and finally abuts against the structural high. In the eastern trough, seismic reflections at the shallow first 300 m are not as fine as in the western trough. These low magnitude seismic reflections might be associated with coarse fluvial volcanoclastic material from nearby Popocatéptl volcano. Seismic amplification in these two tectonic depressions by numerical modelling of seismic wave propagation can be based on the structure here established. Between 8 and 9 high amplitude reflectors in the first 300 m of the infill sequence are interpreted as due to impedance contrasts between geological units. Density and velocity logs along the MexiDrill borehole support this interpretation. Shallow strata are approximately 30 m thick. Towards the basin base, the strata are thicker (70 m approximately). These thicknesses are consistent with the nature of the volcano-sedimentary infill cut by the MexiDrill borehole. In particular, each seismic reflection would represent a sedimentation cycle of approximately 30,000 years (corresponding to a mean thickness of 30 m). If a sedimentation rate of 0.8 mm per year holds along the first 200–300 m of the basin infill (i.e., neglecting compaction effects, etc.) then this upper sequence comprises a record of paleo-ambiental changes that affected the southern Mexico Basin during the last 250,000 to 375,000 years. © 2020 The Authors 2020 English 08959811 10.1016/j.jsames.2020.102722 Journal of South American Earth Sciences 103 Elsevier Ltd Posgrado en Ciencias de La Tierra, UNAM, Mexico City, Mexico; Instituto de Geofísica, UNAM, México City, Mexico; University of Texas at Austin Hildebrand Department of Petroleum and Geosystems Engineering, United States; Instituto Mexicano del Petróleo, Mexico City, Mexico; Petróleos Mexicanos Activo de Producción Samaria Luna Región Sur, Mexico City, Mexico basin analysis; data interpretation; P-wave; seismic data; stratigraphy; transverse isotropy; wave modeling; wave propagation, Chalco; Federal District [Mexico]; Mexico City; Mexico [Mexico (NTN)]; Mexico [North America]; Xochimilco https://www.scopus.com/inward/record.uri?eid=2-s2.0-85087706490&doi=10.1016%2fj.jsames.2020.102722&partnerID=40&md5=55daab76caba58ee4e9895613c0fa01d cited By 0 E. González-Flores J.O. Campos-Enríquez R.V. Wong C. Torres-Verdín D.E. Rivera-Recillas E. Camacho-Ramírez article Timms202012 Hydrothermal activity is a common phenomenon in the wake of impact events, yet identifying and dating impact hydrothermal systems can be challenging. This study provides the first detailed assessment of the effects of shock microstructures and impact-related alteration on the U-Pb systematics and trace elements of titanite (CaTiSiO5), focusing on shocked granite target rocks from the peak ring of the Chicxulub impact structure, Mexico. A &gt; 1 mm long, shock-twinned titanite grain preserves a dense network of irregular microcracks, some of which exploit shock twin interfaces. Secondary microcrystalline anatase and pyrite are heterogeneously distributed along some microcracks. In situ laser ablation multi-collector inductively-coupled plasma mass spectrometry (LA-MC-ICPMS) analysis reveals a mixture of three end-member Pb components. The Pb components are: 1) common Pb, consistent with the Pb isotopic signature of adjacent alkali feldspar; 2) radiogenic Pb accumulated since magmatic crystallization; and 3) a secondary, younger Pb signature due to impact-related complete radiogenic Pb loss. The youngest derived ages define a regression from common Pb that intersects Concordia at 67 ± 4 Ma, in agreement with the established age of 66.04 ± 0.05 Ma for the Chicxulub impact event. Contour maps of LA-MC-ICPMS data reveal that the young ages are spatially restricted to microstructurally-complex domains that correlate with significant depletion in trace elements (REE-Y-Zr-Nb-Mo-Sn-Th) and reduction in magnitude of the Eu/Eu* anomaly. Mapping by time-of-flight secondary ion mass spectrometry (ToF-SIMS) show that patterns of localised element depletion in titanite are spatially related to microcracks, which are enriched in Al. The spatial correlation of ages and trace element abundance is consistent with localised removal of Pb and other trace elements from a pervasive network of fast fluid pathways in fractured domains via a fluid-mediated element transport process associated with the impact event. Here we interpret the 67 ± 4 Ma U-Pb age to represent hydrothermal Pb-loss in the Chicxulub peak ring in the wake of the impact event. These results highlight the potential of our analytical approach using titanite geochronology and geochemistry for dating post-impact hydrothermal activity in impact structures elsewhere. © 2020 Elsevier Ltd 2020 10.1016/j.gca.2020.04.031 Geochimica et Cosmochimica Acta 281 12-30 The Institute for Geoscience Research (TIGeR), Curtin University, Perth, GPO Box U1987WA 6845, Australia; Space Science and Technology Centre, Curtin University, Perth, GPO Box U1987WA 6845, Australia; School of Earth and Planetary Sciences, Curtin University, Perth, GPO Box U1987WA 6845, Australia; Centre for Exploration Targeting – Curtin Node, Curtin University, Perth, GPO Box U1987WA 6845, Australia; John de Laeter Centre, Curtin University, Perth, GPO Box U1987WA 6845, Australia; Institute of Geology, Albert-Ludwigs-Universität, Freiburg, Albertstraße 23b, Freiburg, 79104, Germany; Jacobs – JETS, NASA Johnson Space Center, Astromaterials Research and Exploration Science Division, Mailcode XI3, 2101 NASA Parkway, Houston, TX, United States; Eyring Materials Center, Arizona State University, Tempe, AZ, United States; Natural History Museum, Burgring 7, 1010, Vienna, Austria; Department of Earth Science and Engineering, Imperial College London, London, United Kingdom; Center for Planetary Systems Habitability, Institute for Geophysics and Department of Geological Sciences, Jackson School of Geosciences, University of Texas at Austin, Austin, TX, United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-85084995397&doi=10.1016%2fj.gca.2020.04.031&partnerID=40&md5=b275e7ae541a27aacdc2dec1cf4b83ea cited By 16 N.E. Timms C.L. Kirkland A.J. Cavosie A.S.P. Rae W.D.A. Rickard N.J. Evans T.M. Erickson A. Wittmann L. Ferrière G.S. Collins S.P.S. Gulick article Cui2020 Article 2020 10.1007/s12517-020-05500-w Arabian Journal of Geosciences 13 13 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85086715274&doi=10.1007%2fs12517-020-05500-w&partnerID=40&md5=36f9169ae5b541a5e27f0c2d764d1c50 Cited by: 9 Jingwei Cui Rukai Zhu Chengshan Wang Yuan Gao Sen Li Lei Kang article Pierdominici2020 Knowledge of the in situ stress state of the Earth's crust plays a key role in understanding geological processes including plate tectonics, earthquakes, slope failure, and igneous emplacement. In this paper, we determine the in situ stress orientation from the PTA2 borehole on the island of Hawai'i, drilled into a lava flow dominated sequence between Mauna Kea and Mauna Loa. High-resolution acoustic images were collected from the open hole interval 886 m to 1,567 m. Based on identification of 371 borehole breakouts for a total length of 310 m, the mean orientation of the minimum horizontal principal stress is N106° and remains constant across different volcanic rock fabrics. Changes in borehole breakout shape are linked to the different strength of volcanic facies and intra-facies. The orientation of the present-day stress field at Mauna Kea deviates from the plate forces and regional tectonic stress field. We interpret the compressive stress regime at the PTA2 site as resulting from the competing gravitational fields of the large topographic highs of Mauna Kea and Mauna Loa. Our study reveals that the mass accumulation associated with shield volcano growth imparts significant local variations to the subsurface stress state on volcanic islands consisting of overlapping shield volcanoes. The results have significant implications for stress accumulation leading to brittle failure and flank collapse, along with potentially influencing magma accumulation and ascent pathways during volcanic island evolution. This study provides the first insights into the orientation of the present-day stress field between the major island forming shield volcanoes of Hawai'i. ©2020. The Authors. Article 2020 English 21699313 10.1029/2020JB019768 Journal of Geophysical Research: Solid Earth 125 Blackwell Publishing Ltd 8 Hawaii [(ISL) Hawaiian Islands]; Hawaii [United States]; Hawaiian Islands; Mauna Kea; Mauna Loa; borehole breakout; in situ stress; lava flow; shield volcano; stress field; volcanic island https://www.scopus.com/inward/record.uri?eid=2-s2.0-85089831311&doi=10.1029%2f2020JB019768&partnerID=40&md5=d8e21ec53f3ba5c08effa092746604e2 Cited by: 2; All Open Access, Green Open Access, Hybrid Gold Open Access John M. Millett Jochem K. M. Kück Donald Thomas Dougal A. Jerram Sverre Planke Eric Haskins Nicole Lautze Olivier Galland article cocomazzi2020formation 2020 Minerals 10 MDPI 167 2 Giuseppe Cocomazzi Giovanni Grieco Paola Tartarotti Micol Bussolesi Federica Zaccarini Laura Crispini Oman Drilling Project Science Team article Wang2020 The stress state down to the basement within sedimentary basins yet remains poorly understood. The anelastic strain recovery (ASR) method was employed to measure the stress state in the SK-II borehole in the Songliao Basin, Northeast China. The results show that the stress state differs significantly between the sedimentary cover and basement. In the sedimentary cover (6296–6335 m), the maximum principal stress σ1 is nearly vertical, which is in the normal faulting stress regime dominated by gravitation, in accordance with the normal faults observed on seismic reflection profiles within the sedimentary cover. In contrast, the basement (6646–6846 m) shows that σ1 is nearly horizontal, suggesting a strike-slip or reverse-faulting regime. The stress state of the basement is close to the reasonable stress condition for the Eurasian Plate far from a western Pacific plate subduction zone and consistent with the focal mechanisms of earthquakes (7–15 km) in the vicinity of ICDP SK-II borehole. The difference of stress state may imply that the far-field stress generated by the western Pacific plate has limited effects on the sedimentary cover, an increase in thickness correlates with an increasing influence of tectonic stress with depth. © 2020 Elsevier B.V. 2020 English 00401951 10.1016/j.tecto.2020.228337 Tectonophysics 777 Elsevier B.V. Key Laboratory of Active Tectonics and Crustal Stability Assessment, Institute of Geomechanics, Chinese Academy of Geological Sciences, Beijing, 100081, China; Graduate School of Engineering, Kyoto University, Kyoto, 615-8540, Japan Boreholes; Buildings; Sedimentology; Stresses; Strike-slip faults, Anelastic strain recovery; In-situ stress measurement; Insitu stress; Maximum principal stress; Scientific drilling; Seismic reflection profiles; Songliao basin; Stress state, Fault slips, anelasticity; basement rock; borehole; depth; drilling; in situ measurement; normal fault; Pacific plate; sedimentary basin; seismic reflection; strain analysis; stress field, China; Songliao Basin https://www.scopus.com/inward/record.uri?eid=2-s2.0-85079002476&doi=10.1016%2fj.tecto.2020.228337&partnerID=40&md5=78fbbfe8f075ebd719dae61384698335 cited By 4 B. Wang D. Sun Q. Chen W. Lin A.-W. Li H. Cao article Sharov2020253 Attempts to interpret the origin of seismic boundaries in the crystalline crust in the Fennoscandian Shield from deep drilling records and available geological and geophysical data were made by a number of authors. This article contains an overview of the most essential results reported so far. Deep drilling was conducted in several regions of the Fennoscandian Shield: Kola, Russia (SG-3), to a depth of 12,262 m (1970–1990); Gravberg (GR) and Stenberg-I, Central Sweden, to a depth of 6337 m (1986–1987); and 6529 m (1991–1992); Outokumpu (OU), SE Finland, to a depth of 2516 m (2004–2005); Pogranichnaya (P-1), Sredny Peninsula, Murmansk Region, Russia, to a depth of 5200 m (2004–2006); and Onega, Central Karelia, Russia (ON), to a depth of 3537 m (2007–2008). The results obtained were analyzed. They show considerable discrepancies between forecast seismic-geological models and the actual structure of the upper portion of the continental crust. Deep drilling has proved that heterogeneities in the upper portion of the crystalline crust, indicated by geophysical data, are due to changes in the composition and physical conditions of deep-seated rocks. Therefore, even approximate rock composition cannot be uniquely estimated from elastic wave velocities alone. Deep drilling showed the real pattern and origin of low-velocity zones in the upper portion of the crust and did not show that layers become more homogeneous with depth. The origin of intra-crustal seismic boundaries could be associated with various factors, such as variations in mineralogical composition, structural and textural differences between the rocks, and a thermodynamic setting. © 2020, Springer Nature Switzerland AG. Book chapter 2020 English 2524342X 10.1007/978-3-030-21788-4_21 Springer Proceedings in Earth and Environmental Sciences Springer Nature 253 – 261 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85125246957&doi=10.1007%2f978-3-030-21788-4_21&partnerID=40&md5=b40b0e8fdb4e7a3a6ccede2effd18300 Cited by: 3 N.V. Sharov article Zaova20201 Article 2020 10.5852/ejt.2020.670 European Journal of Taxonomy 2020 1 – 14 670 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85090735086&doi=10.5852%2fejt.2020.670&partnerID=40&md5=1f91d15d362f66d47a199e3524bf5459 Cited by: 2; All Open Access, Gold Open Access, Green Open Access Dušica Zaova Aleksandra Cvetkoska Danijela Mitic-Kopanja Elena Jovanovska Nadja Ognjanova-Rumenova Zlatko Levkov article Irurzun2020113 Article 2020 10.1017/qua.2020.15 Quaternary Research (United States) 95 113 – 128 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85084759468&doi=10.1017%2fqua.2020.15&partnerID=40&md5=8618d6b8169bf90fead52abfdf8c90e0 Cited by: 3 Mariá A. Irurzun Pedro Palermo Claudia S. G. Gogorza Ana M. Sinito Milagrosa Aldana Vincenzo Costanzo-Álvarez Christian Ohlendorf Bernd Zolitschka inproceedings webb2020bushveld 2020 AGU Fall Meeting Abstracts 2020 NS008--01 Susan Jane Webb Robert Bruce Trumbull Lewis D Ashwal Frederick Roelofse David Khoza Ben Hayes article Hamilton2020 Any palynologist who has worked in the tropics has undoubtedly dealt with the frustration of trying to classify small, tricolporate pollen into meaningful taxonomic groups. While this is not a significant issue where coarse-scale identifications represent similar habitat indicators or “unknown” types are rare, it poses a problem when one of these “unknowns” overwhelm the record. This is the case with unknown “type 69” – a small, tricolporate pollen grain encountered within a 60,000-year sediment sequence from Lake Towuti in Sulawesi, Indonesia. This type comprises up to 35% of the pollen count for some Last Glacial Maximum (LGM) samples (highlighting its climatic sensitivity) but could not be identified by experts in the field. This study thus aimed to compare the metrics of “type 69” with reference pollen from Sulawesi to aid with its identification. In doing so, we present a pollen atlas of 63 maritime southeast Asian pollen types. Our results show that “type 69” aligns with metrics taken from Saurauia pollen. While detailed ecological data on Saurauia species in Sulawesi are lacking, they appear to favor higher elevations and riverbank settings, and are post-disturbance colonizers. Proliferation of this pollen type during the LGM is therefore linked to a combination of downslope range expansion of Saurauia species under a cooler climate and potentially, out competition of upland everwet forest taxa. This study demonstrates an approach to managing important unknown fossil pollen types in tropical records and, through the ensuing pollen atlas, provides a tool for progressing palynology in southeast Asia. © 2019 Elsevier B.V. Article 2020 English 00346667 10.1016/j.revpalbo.2019.104146 Review of Palaeobotany and Palynology 273 Elsevier B.V. Greater Sunda Islands; Indonesia; Lake Towuti; Malili Lakes; South Sulawesi; Sulawesi; Sunda Isles; Saurauia; colonization; fossil record; Last Glacial Maximum; palynology; range expansion; river bank; sedimentary sequence https://www.scopus.com/inward/record.uri?eid=2-s2.0-85075997785&doi=10.1016%2fj.revpalbo.2019.104146&partnerID=40&md5=35e09bd5879c1ba2a0c9e4771da010a8 Cited by: 1 R. Hamilton J. Stevenson article Xu20201212 The Cretaceous nonmarine sedimentary strata are widespread in Songliao Basin, Northeast China. As the largest oil producer in China, an abundance of data has been generated by the petroleum industry, including sedimentology, seismology, geochemistry, and geochronology in the Songliao Basin. This article reviews the achievements in China Cretaceous Continental Scientific Drilling SK and presents the new results of the China Continental Geothermal Drilling SR1 in stratigraphy and geophysics. The results allow us to establish the relationships among SK-1, SK-2, and SR1, provide some constrains on the tectonic setting of Songliao Basin, and interpret the sedimentary facies and environmental evolution. After stratigraphic correlation of SK and SR boreholes, the result indicates that the geological boundary between the late Cretaceous Mingshui formation and the Paleogene Yi'an formation is at the depth of 115 m. The magnetotelluric sounding anomaly areas are corresponding with the unconformities, which are equivalent to seismic horizon T03, T1, T2, and T3, respectively. In addition, the typical "steer's-head"geometry in the magnetotellurics indicates that the SLB has experienced five evolution stages. © 2020 Zhihe Xu et al., published by De Gruyter 2020. Article 2020 English 23915447 10.1515/geo-2020-0188 Open Geosciences 12 De Gruyter Open Ltd 1212 – 1223 College of Earth Science and Engineering, Shandong University of Science and Technology, Qingdao, 266590, China; Hebei Geological Survey Institute, Hebei, 050000, China; Jilin Exploration Geophysics Institute, Changchun 130000, China; College of Earth Sciences, Taiyuan University of Technology, Taiyuan, 030000, China 1 China; Songliao Basin; Geochronology; Infill drilling; Magnetotellurics; Petroleum industry; Sedimentology; Seismology; Stratigraphy; Continental scientific drillings; Environmental evolution; Geological boundaries; Geothermal drilling; Magnetotelluric soundings; Sedimentary facies; Sedimentary strata; Stratigraphic correlation; borehole geophysics; Cretaceous; drilling; geometry; magnetotelluric method; stratigraphic correlation; tectonic setting; Petroleum geology https://www.scopus.com/inward/record.uri?eid=2-s2.0-85095833894&doi=10.1515%2fgeo-2020-0188&partnerID=40&md5=096c657292be343db7dbe9409ef0c3c9 Cited by: 0; All Open Access, Gold Open Access Zhihe Xu Qinglin Xu Aitao Liu Naichen Wang Guangxiang Li Chong Peng Leilei Yan Yongfei Su article Bauer2020 Burial of large quantities of magnetite (Fe(II)Fe(III)2O4) in iron formations (IFs) likely contributed to the protracted oxidation of Earth's surface during the Precambrian Eons. Magnetite can form through a diversity of biological and abiotic pathways and its preservation in IFs may thus be variably interpreted as the result of some combination of these processes. Such interpretations give rise to divergent pictures of the Precambrian Earth system and models for its evolution through time. New knowledge on the contribution of specific magnetite formation pathways is, therefore, needed to accurately tether our conceptual and numerical models to the geologic record. To constrain pathways of magnetite formation under ferruginous conditions, we conducted geochemical and multi-method microspectroscopic analyses on particles obtained from the water columns and sediments of ferruginous lakes Matano and Towuti, in Indonesia. We find that biologically reactive Fe(III) mineral phases are reduced in the anoxic waters of both lakes, causing the formation of primary authigenic magnetite, directly in the water column. This water column magnetite often takes conspicuous framboidal forms, which given the link to microbial Fe(III) reduction, may provide a biological signature on early Earth and by extension, other planetary bodies. The consumption of more biologically reactive forms of Fe(III) and the resulting delivery of primary magnetite to underlying sediments promotes the burial of oxidized equivalents and implies that primary magnetite formation could have been a principal pathway of Fe delivery to IFs. Combined, the removal of Fe from Earth's surface through biologically induced magnetite formation and subsequent burial in IFs, suggests that seawater chemistry and the microbially mediated reactions that cause magnetite formation played key roles in Earth system evolution and in setting the pace for planetary oxidation through the Precambrian Eons. © 2020 Article 2020 English 0012821X 10.1016/j.epsl.2020.116495 Earth and Planetary Science Letters 549 Elsevier B.V. Greater Sunda Islands; Lake Matano; Lake Towuti; Malili Lakes; South Sulawesi; Sulawesi; Sunda Isles; Biology; Biomineralization; Geologic models; Lakes; Magnetite; Ore reduction; Oxidation; Abiotic pathways; Biological signatures; Earth's surface; Magnetite formation; Mediated reactions; Planetary bodies; Precambrian eons; Seawater chemistry; biomineralization; early Earth; evolution; lacustrine deposit; magnetite; mass spectrometry; oxidation; Precambrian; water column; Iron compounds https://www.scopus.com/inward/record.uri?eid=2-s2.0-85089556687&doi=10.1016%2fj.epsl.2020.116495&partnerID=40&md5=29b4c47bce8584158d0568916a2c7765 Cited by: 6; All Open Access, Green Open Access K.W. Bauer J.M. Byrne P. Kenward R.L. Simister C.C. Michiels A. Friese A. Vuillemin C. Henny S. Nomosatryo J. Kallmeyer A. Kappler M.A. Smit R. Francois S.A. Crowe article Lu2020 Recording and analyzing how climate change impacts flood recurrence, basin erosion, and sedimentation can improve our understanding of these systems. The aragonite-detritus laminae couplets comprising the lacustrine formations that were deposited in the Dead Sea are considered as faithful monitors of the freshwater supply to the lakes. We count a total of ∼5600 laminae couplets deposited in the last 45 kyr (MIS3-MIS1) at the Dead Sea center, which encompass the upper 142 m of the ICDP Core 5017-1. The present study shows that aragonite and detritus laminae are thinner and occur at high frequency during MIS 3-2, while they are much thicker and less frequent during MIS 1. By analyzing multiple climate-connected factors, we propose that significant lake-level drops, enhanced dust input, and low vegetative cover in the drainage basin during the last deglaciation (22-11.6 ka) have considerably increased erodible materials in the Dead Sea watershed. We find a decoupling existed between the significant lake-level drop/lake size reduction and lamina thickness change during the last deglaciation. We argue that during the Last Glacial and the Holocene, the variation of lamina thickness at the multiple-millennium scale was not controlled directly by the lake-level/size change. We interpret this decoupling implying the transport capacity of flash-floods is low and might be saturated by the oversupply of erodible materials, and indicating a transport-limited regime during the time period. We suggest the observed thickness and frequency distribution of aragonite-detritus laminae points to the high frequency of small-magnitude floods during the Last Glacial, in contrast to low frequency, but large-magnitude floods during the Holocene. © 2019 Elsevier Ltd 2020 English 02773791 10.1016/j.quascirev.2019.106143 Quaternary Science Reviews 229 Elsevier Ltd Sedimentology and Marine Paleoenvironmental Dynamics Group, Institute of Earth Sciences, Heidelberg University, Heidelberg, 69120, Germany; Dr. Moses Strauss Department of Marine Geosciences, Leon H. Charney School of Marine Sciences, University of Haifa, Mount Carmel3498838, Israel; Department of Geophysics, Tel Aviv University, Tel Aviv, 6997801, Israel Carbonate minerals; Catchments; Drops; Erosion; Floods; Glacial geology; Lakes; Paleolimnology; Seawater, Aragonite-detritus laminae; Dead sea; Flash flood; Magnitude-frequency; Transport-limited regime, Climate change, basin analysis; climate change; climate effect; erosion; flash flood; flood; flood frequency; historical record; Holocene; Last Glacial; magnitude; marine isotope stage; paleolimnology; sedimentation, Dead Sea https://www.scopus.com/inward/record.uri?eid=2-s2.0-85076924820&doi=10.1016%2fj.quascirev.2019.106143&partnerID=40&md5=7927e1d5c8f48e9b3d2842b264a7a0aa cited By 13 Y. Lu R. Bookman N. Waldmann S. Marco article McPhie2020LithofaciesFT 2020 10.33112/surtsey.14.2 https://api.semanticscholar.org/CorpusID:225844014 Jocelyn McPhie James D. L. White Carolyn F. Gorny Marie D. Jackson Magnús Tumi Gudmundsson SAMANTHA COUPER article Liang2020 Undiscernible faults on seismic reflection profiles are referred to as subseismic faults. Although most subseismic faults are undetected, they play a significant role in understanding regional tectonic evolution and can influence the flow of oil and gas. The Songliao Basin in NE China is a typical Meso-Cenozoic continental petroliferous basin characterized by stable sedimentation, rift-depression dual structure, and large-scale oil and gas production. However, the characteristics of subseismic faults and their effect on petroleum resources remain not well understood. Here we reported findings from the SK-2 east borehole located in the Songliao Basin, which is the deepest (7018 m deep below ground surface) continental scientific drilling borehole in East Asia. We identified 46 subseismic faults at 2900-4200 m depth based on observations of core- scanning images, macro- and micro-structures, and well-logging data. Macro- and micro-structural analyses indicate that most of the subseismic faults in the borehole show normal slip. These observations suggest these subseismic faults may form in response to regional extension in the Shahezi (K1sh) period. The cross-cutting relationships among several groups of sheared fault planes or elongated veins filled in the fractures likely reflect multi-stage faulting. The subseismic faults are considered to be related to the nearby larger-scale faulting as interpreted on the seismic profile. Spatial correlation between the observed subseismic faults and elevated hydrocarbon concentrations documented by borehole mud gas logging suggests that the subseismic faults might have controlled gas migration in the study area. © 2020 Society of Exploration Geophysicists and American Association of Petroleum Geologists. Article 2020 English 23248858 10.1190/int-2019-0068.1 Interpretation 8 Society of Exploration Geophysicists 2 China; Songliao Basin; borehole; fault zone; gas flow; gas well; hydrocarbon migration; hydrocarbon resource; oil well; petroleum hydrocarbon; reservoir characterization; seismic reflection; tectonic evolution; tectonic setting; well logging https://www.scopus.com/inward/record.uri?eid=2-s2.0-85081207737&doi=10.1190%2fint-2019-0068.1&partnerID=40&md5=671997c042c72505a3ddcc39feabbe1d Cited by: 0 Shujun Liang Wei Gan Chengshan Wang article Peng2020 Continuous and high-resolution well logs from the SK-2 east (SK-2e) borehole in the Songliao Basin provide an opportunity to understand the relationship between astronomically forced climate and electrical responses in terrestrial Cretaceous strata. Here, we present well logs, mud logs, and core measurement data of lacustrine deposits in the Upper Cretaceous Qingshankou Fm and of fluvial/deltaic deposits in the Quantou Fm. The multiresolution resistivity logs used for the cyclostratigraphic analysis include deep laterolog resistivity logs, resistivity image logs, and array induction logs. The results show that the resistivity of strata in Quantou Fm mainly reflects changes in clay content, and that resistivity logs can be used as paleoenvironmental and paleoclimate proxies in cyclostratigraphic studies of the Quantou Fm. For the Qingshankou Fm, formation resistivity is mainly affected by clay minerals, which contribute to the overall electrical conductivity, as well as nonconductive organic carbon. Increasing clay and organic carbon contents usually correspond to wetter and warmer climatic conditions. The phase relationship between resistivity logs and astronomical cyclicity depends on factors that control resistivity. Spectral analyses of lithological changes and resistivity logs indicate the presence of eccentricity, obliquity, and precession cycles throughout the Quantou Fm. This provides strong evidence that climate was the dominant control on cyclic sedimentation in the Quantou Fm. The floating astronomical timescale, which was established by calibrating extracted 405-kyr cycles from resistivity logs, reveals that the duration of Quantou Fm was approximately 5.5 Myr. Comparative analysis of power spectra reveals that the sensitivity of resistivity logs with specific resolutions to Milankovitch cycles with different frequencies is variable. Comprehensive analysis of multiresolution resistivity logs is a new method in cyclostratigraphy analysis that has the potential to be effective in detecting signals of Milankovitch cycles in terrestrial deposits. © 2020 Elsevier B.V. 2020 English 00310182 10.1016/j.palaeo.2020.109858 Palaeogeography, Palaeoclimatology, Palaeoecology 555 Elsevier B.V. Key Laboratory of Geo-detection (China University of Geosciences, Beijing), Ministry of Education, Beijing, 100083, China; School of Geophysics and Information Technology, China University of Geosciences, Beijing, 100083, China; State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing, 100083, China; School of Ocean Sciences, China University of Geosciences, Beijing, 100083, China; Chinese Academy of Geological Sciences, Beijing, 100037, China borehole; Cretaceous; cyclic sedimentation; cyclostratigraphy; organic carbon; paleoclimate, China; Songliao Basin https://www.scopus.com/inward/record.uri?eid=2-s2.0-85086774149&doi=10.1016%2fj.palaeo.2020.109858&partnerID=40&md5=dc8f3f812ad14d038d2dac9582d05a5e cited By 7 C. Peng C. Zou S. Zhang H. Wu Q. Lü H. Hou C. Wang article Coianiz2020636 The Dead Sea is an extensional basin developing along a transform fault plate boundary. It is also a terminal salt basin. Without knowledge of precise stratigraphy, it is difficult to differentiate between the role of plate and salt tectonics on sedimentary accumulation and deformation patterns. While the environmental conditions responsible for sediment supply are reasonably constrained by previous studies on the lake margins, the current study focuses on deciphering the detailed stratigraphy across the entire northern Dead Sea basin as well as syn and post-depositional processes. The sedimentary architecture of the late Quaternary lacustrine succession was examined by integrating 851 km of seismic reflection data from three surveys with gamma ray and velocity logs and the stratigraphic division from an ICDP borehole cored in 2010. This allowed seismic interpretation to be anchored in time across the entire basin. Key surfaces were mapped based on borehole lithology and a newly constructed synthetic seismogram. Average interval velocities were used to calculate isopach maps and spatial and temporal sedimentation rates. Results show that the Amora Formation was deposited in a pre-existing graben bounded by two N-S trending longitudinal faults. Both faults remained active during deposition of the late Pleistocene Samra and Lisan Formations—the eastern fault continued to bound the basin while the western fault remained blind. On-going plate motion introduced a third longitudinal fault, increasing accommodation space westwards from the onset of deposition of the Samra Formation. During accumulation of these two formations, sedimentation rates were uniform over the lake and similar. High lake levels caused an increase in hydrostatic pressure. This led to salt withdrawal, which flowed to the south and southwest causing increased uplift of the Lisan and En Gedi diapirs and the formation of localized salt rim synclines. This induced local seismicity and slumping, resulting in an increased thickness of the Lisan succession within the lake relative to its margins. Sedimentation rates of the Holocene Ze'elim Fm were 4–5 times higher than before. The analysis presented here resolves central questions of spatial extent and timing of lithology, deposition rates and their variability across the basin, timing of faulting at and below the lake floor, and timing and extent of salt and plate tectonic phases and their effect on syn and post-depositional processes. Plate tectonics dictated the structure of the basin, while salt tectonics and sediment accumulation were primarily responsible for its fill architecture during the timeframe examined here. © 2019 The Authors. Basin Research © 2019 John Wiley & Sons Ltd, European Association of Geoscientists & Engineers and International Association of Sedimentologists 2020 English 0950091X 10.1111/bre.12387 Basin Research 32 Blackwell Publishing Ltd 636-651 Dr. Moses Strauss Department of Marine Geosciences, Leon H. Charney School of Marine Sciences, University of Haifa, Haifa, Israel; Department of Geophysics and Planetary Sciences, Tel-Aviv University, Tel-Aviv, Israel 4 deformation mechanism; neotectonics; plate boundary; plate motion; plate tectonics; Quaternary; salt tectonics; sedimentation rate; seismic reflection; stratigraphy; structural control; structural geology, Dead Sea https://www.scopus.com/inward/record.uri?eid=2-s2.0-85081317927&doi=10.1111%2fbre.12387&partnerID=40&md5=e1b3f1e51261492070f2d3e5e069dfbb cited By 2 L. Coianiz U. Schattner G. Lang Z. Ben-Avraham M. Lazar article Jordan202075 In January 2020, a scientific borehole planning workshop sponsored by the International Continental Scientific Drilling Program was convened at Cornell University in the northeastern United States. Cornell is planning to drill test wells to evaluate the potential to use geothermal heat from depths in the range of 2700-4500 m and rock temperatures of about 60 to 120 °C to heat its campus buildings. Cornell encourages the Earth sciences community to envision how these boreholes can also be used to advance high-priority subsurface research questions. Because nearly all scientific boreholes on the continents are targeted to examine iconic situations, there are large gaps in understanding of the "average" intraplate continental crust. Hence, there is uncommon and widely applicable value to boring and investigating a "boring" location. The workshop focused on designing projects to investigate the coupled thermal-chemical-hydrological-mechanical workings of continental crust. Connecting the practical and scientific goals of the boreholes are a set of currently unanswered questions that have a common root: the complex relationships among pore pressure, stress, and strain in a heterogeneous and discontinuous rock mass across conditions spanning from natural to human perturbations and short to long timescales. The need for data and subsurface characterization vital for decision-making around the prospective Cornell geothermal system provides opportunities for experimentation, measurement, and sampling that might lead to major advances in the understanding of hydrogeology, intraplate seismicity, and fluid/chemical cycling. Subsurface samples could also enable regional geological studies and geobiology research. Following the workshop, the U.S. Department of Energy awarded funds for a first exploratory borehole, whose proposed design and research plan rely extensively on the ICDP workshop recommendations. © 2020 Copernicus GmbH. All rights reserved. 2020 English 18168957 10.5194/sd-28-75-2020 Scientific Drilling 28 Copernicus GmbH 75-91 Earth and Atmospheric Sciences, Cornell University, Ithaca, NY 14853, United States; Chemical and Biomolecular Engineering, Cornell University, Ithaca, NY 14853, United States; Civil Engineering and Geosciences, Delft University of Technology, Delft, 2600, Netherlands; National Institute of Advanced Industrial Science and Engineering, Fukushina Renewable Energy Research Institute, Koriyama, Fukushima Prefecture, 963-0298, Japan; ICDP/Geomechanics and Scientific Drilling, GFZ German Research Centre for Geosciences, Potsdam, 14473, Germany; Physics and Astronomy, Purdue University, West Lafayette, IN 47907, United States; Earth, Atmospheric and Planetary Sciences, Purdue University, West Lafayette, IN 47907, United States; Geoscience and Engineering, Delft University of Technology, Delft, 2628 CN, Netherlands; Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences, Potsdam, 14473, Germany; Gulf Plains Prospecting Company, Kingwood, TX 77345, United States; Engineering Systems and Environment, University of Virginia, Charlottesville, VA 22904, United States Boring; Decision making; Geothermal fields; Groundwater; Hydrogeology; Infill drilling, Complex relationships; Continental scientific drillings; Discontinuous rock mass; Intraplate seismicity; Mechanical working; Subsurface characterizations; Subsurface research; U.S. Department of Energy, Exploratory boreholes https://www.scopus.com/inward/record.uri?eid=2-s2.0-85097253936&doi=10.5194%2fsd-28-75-2020&partnerID=40&md5=299eb4514fb875504253bcd944093d3b cited By 1 T. Jordan P. Fulton J. Tester D. Bruhn H. Asanuma U. Harms C. Wang D. Schmitt P.J. Vardon H. Hofmann T. Pasquini J. Smith Workshop Participants article menzel2020brittle 2020 Journal of Geophysical Research: Solid Earth 125 Wiley Online Library e2020JB020199 10 Manuel D Menzel Janos L Urai Juan Carlos Obeso Alissa Kotowski Craig E Manning Peter B Kelemen Michael Kettermann Ana P Jesus Yumiko Harigane Oman Drilling Project Phase 1 Science Team article Dorfler2020441 Depending on their sizes, impact craters have either simple or complex geometries. Peak-ring craters such as the Chicxulub impact structure possess a single interior ring of peaks and hills and a flat interior floor. The exact mechanisms leading to the formation of a morphological peak-ring are still a matter of debate. In this study, analog modeling was used to study the flow field of a collapsing central uplift. A 3-D-printed cast was used to bring the analog material in the shape of an overheightened central uplift that was based on numerical modeling. The cast was then quickly removed and the central peak collapsed, forming a flattened broad mound that spread out onto the annular moat of the crater cavity. A subwoofer was used to fluidize the granular target material. The kinematics of the collapse were analyzed with the aid of particle image velocimetry, revealing a downward and outward collapse of the central uplift. This mode of collapse is partly in agreement with numerical models, in particular for the initial and middle phases. The overthrusting of the collapsing central peak onto the inward moving crater floor predicted by numerical modeling was observed, though to a lesser degree. A peak-ring, however, could not be reproduced since the collapse came to a halt before the central peak was completely leveled. Nevertheless, the method provides qualitative insights into the kinematics of collapse phenomena. This experimental study provides independent support of the theory of acoustic fluidization, in addition to numerical simulations. © 2020 The Authors. Meteoritics & Planetary Science published by Wiley Periodicals, Inc. on behalf of The Meteoritical Society (MET) 2020 10.1111/maps.13442 Meteoritics and Planetary Science 55 441-456 Institut für Geo- und Umweltnaturwissenschaften, Geologie, Albert-Ludwigs-Universität Freiburg, Albertstrasse 23-B, Freiburg, 79104, Germany 2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85079047705&doi=10.1111%2fmaps.13442&partnerID=40&md5=6c9fd4bfe65a0e1131c1f44b254ed06a cited By 2 M.A. Dörfler T. Kenkmann article Feignon20202206 Planar deformation features (PDFs) in quartz are a commonly used and well-documented indicator of shock metamorphism in terrestrial rocks. The measurement of PDF orientations provides constraints on the shock pressure experienced by a rock sample. A total of 963 PDF sets were measured in 352 quartz grains in 11 granite samples from the basement of the Chicxulub impact structure’s peak ring (IODP-ICDP Expedition 364 drill core), with the aim to quantify the shock pressure distribution and a possible decay of the recorded shock pressure with depth, in the attempt to better constrain shock wave propagation and attenuation within a peak ring. The investigated quartz grains are highly shocked (99.8% are shocked), with an average of 2.8 PDF sets per grain; this is significantly higher than in all previously investigated drill cores recovered from Chicxulub and also for most K-Pg boundary samples (for which shocked quartz data are available). PDF orientations are roughly homogenous from a sample to another sample and mainly parallel to {10 (Formula presented.) 3} and {10 (Formula presented.) 4} orientations (these two orientations representing on average 68.6% of the total), then to {10 (Formula presented.) 2} orientation, known to form at higher shock pressure. Our shock pressure estimates are within a narrow range, between ~16 and 18 GPa, with a slight shock attenuation with increasing depth in the drill core. The relatively high shock pressure estimates, coupled with the rare occurrence of basal PDFs, i.e., parallel to the (0001) orientation, suggest that the granite basement in the peak ring could be one of the sources of the shocked quartz grains found in the most distal K-Pg boundary sites. © 2020 The Authors. Meteoritics & Planetary Science published by Wiley Periodicals LLC on behalf of The Meteoritical Society (MET) 2020 10.1111/maps.13570 Meteoritics and Planetary Science 55 2206-2223 Department of Lithospheric Research, University of Vienna, Althanstrasse 14, Vienna, A-1090, Austria; Natural History Museum, Burgring 7, Vienna, A-1010, Austria; Univ-Lille, CNRS, INRAE, Centrale Lille, UMR 8207 – UMET – Unité Matériaux et transformations, Villeneuve d'Ascq, 59655, France 10 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85091786850&doi=10.1111%2fmaps.13570&partnerID=40&md5=88b9ed7c55daad7634052fe26b2c905a cited By 11 J.-G. Feignon L. Ferrière H. Leroux C. Koeberl article Ortega-Guerrero2020 Sediments from Lake Chalco in central Mexico spanning from ca. 150 to 35 ka ago provide evidence of paleoclimatic variability in the North American tropics associated with the end of Marine Isotopic Stage (MIS) 6, the transition to the last interglacial (MIS 5.5, ca. 130-115 ka ago), and part of the last glacial (MIS 5.4 to early MIS 3, 115 to 35 ka ago). We applied a multiproxy approach based on the analysis of mineral magnetism, diatom assemblages and major elements geochemistry. The reconstructed paleoenvironmental history identify the end of the globally cool MIS 6 as wetter than present, with high lake level, and a subsequent change to drier climates at the onset of the last interglacial (ca. 130 ka). Large amplitude changes in most of the analyzed parameters from ca. 130 to 74 ka are approximately coincident with MIS 5 (130-71 ka). The amplitude of these changes decreases in MIS 4 (71-57 ka) and the early part of MIS 3 (57-35 ka). We proposed that the inferred climatic oscillations follow insolation variations during MIS 6 and part of MIS 5 (150-88 ka). Low summer and spring insolation and lower seasonality inhibited evaporation and favored high lake levels. Conversely, maxima in spring and summer insolation promoted dry conditions and low lake levels. The major wet-cold glacial and dry-warm interglacial relationship found in Lake Titicaca (Bolivia) and Lake Chalco records shows the sensitivity of high altitude tropical sites to climatic variability. © 2020 Elsevier Ltd 2020 English 02773791 10.1016/j.quascirev.2020.106163 Quaternary Science Reviews 230 Elsevier Ltd Universidad Nacional Autónoma de México, Instituto de Geofísica, Ciudad de México, 04150, Mexico; Universidad Nacional Autónoma de México, Posgrado en Ciencias de la Tierra, Ciudad de México, 04150, Mexico; Universidad Nacional Autónoma de México, Instituto de Geología, Ciudad de México, 04150, Mexico; University of Minnesota Duluth, Large Lakes Observatory and Department of Geological Sciences, Duluth, MN 55812, United States Glacial geology; Incident solar radiation; Magnetic properties; Magnetism; Minerals; Paleolimnology; Tropics, Climatic oscillations; Climatic variability; Interglacial(s); Magnetic mineralogy; Marine isotopic stages; Multiproxy approach; North America; Pleistocene, Lakes, interglacial; Last Glacial Maximum; Last Interglacial; magnetic property; marine isotope stage; mineralogy; paleoclimate; paleolimnology; Pleistocene; reconstruction; seasonal variation; seasonality, Bolivia; Lake Chalco; Lake Titicaca; Mexico [North America], Bacillariophyta https://www.scopus.com/inward/record.uri?eid=2-s2.0-85077947755&doi=10.1016%2fj.quascirev.2020.106163&partnerID=40&md5=72054372ef57a7a644474f59af867f5b cited By 12 B. Ortega-Guerrero D. Avendaño M. Caballero S. Lozano-García E.T. Brown A. Rodríguez B. García H. Barceinas A.M. Soler A. Albarrán conference Nixon2020 Anomalous values of in-situ compressional wave speeds (VP) and quality factors (Q), determined from analysis of borehole seismic measurements are found within the highly damaged rock mass in the peak ring materials of the K-Pg Chicxulub impact structure. The data is obtained from vertical seismic profiling of IODP/ICDP hole M0077A, drilled to 1335 m depth. VP, calculated by local slope regression, are ~4 km/s, only about 60% that for similar unshocked polycrystalline granite. Attenuation is quantified using the spectral ratios method that gives low Q factors of 10 to 35, values that are significantly less than expected for unshocked granites. Previous in-situ studies measuring physical properties of complex crater central uplifts remain rare; the extraordinary geo-mechanical results from these analyses are presented as impetus for future studies on the poorly understood physical properties and formation of impact basin peak rings as well as providing insight into seismic wave propagation through highly damaged rock masses. © 2020 ARMA, American Rock Mechanics Association 2020 54th U.S. Rock Mechanics/Geomechanics Symposium University of Alberta, Edmonton, AB, Canada; Purdue University, West Lafayette, IN, United States; University of Texas Institute for Geophysics, Austin, TX, United States; Université de Montpellier, Montpellier, Languedoc-Roussillon, France; Imperial College London, London, United Kingdom https://www.scopus.com/inward/record.uri?eid=2-s2.0-85097945980&partnerID=40&md5=8bae17c025d401e4a81952b079df529a cited By 0 C.G. Nixon R. Kofman S.P.S. Gulick G.L. Christeson S. Saustrup J. Lofi J.V. Morgan article Scheller2020 The western part of the Isidis basin structure hosts a well-characterized Early Noachian to Amazonian stratigraphy. The Noachian Basement comprises its oldest exposed rocks (Early to Mid-Noachian) and was previously considered a single low-Ca pyroxenes (LCP)- and Fe/Mg-smectite-bearing unit. Here, we divide the Noachian Basement Group into five distinct geological units (Stratified Basement Unit, Blue Fractured Unit, Mixed Lithology Plains Unit, LCP-bearing Plateaus Unit, and Fe/Mg-smectite-bearing Mounds Unit), two geomorphological features (megabreccia and ridges), and a mineral deposit (kaolinite-bearing bright materials), based on geomorphology, spectral characteristics, and stratigraphic relationships. Megabreccia contain four different pre-Isidis lithologies, possibly including deeper crust or mantle materials, formed through mass wasting associated with transient crater collapse during Isidis basin formation. The Fe/Mg-smectite-bearing Stratified Basement Unit and LCP-bearing Blue Fractured Unit likewise represent pre-Isidis units within the Noachian Basement Group. Multiple Fe/Mg-smectite-bearing geological units with different stratigraphic positions and younger kaolinite-bearing bright materials indicate several aqueous alteration episodes of different ages and styles. Units with slight changes in pyroxene spectral properties suggest a transition from low-Ca pyroxene-containing materials to those with higher proportions of pyroxenes higher in Ca and/or glass that could be related to different impact and/or igneous processes, or provenance. This long history of Noachian and potentially Pre-Noachian geological processes, including impact basin formation, aqueous alteration, and multiple igneous and sedimentary petrogeneses, records changing ancient Mars environmental conditions. All units defined by this study are available 20 km outside of Jezero crater for in situ analysis and sampling during a potential extended mission scenario for the Mars 2020 rover. ©2020. The Authors. 2020 10.1029/2019JE006190 Journal of Geophysical Research: Planets 125 Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, United States; Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, United States 7 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85088599065&doi=10.1029%2f2019JE006190&partnerID=40&md5=8fb5bf285b0909d7eb2496ff748f8217 cited By 16 E.L. Scheller B.L. Ehlmann article Jacob2020 We have investigated the laboratory-scale, high-strain rate tensile failure processes responsible for Mode-I breccia dike formation in impact structures. Brazilian disc experiments with granite (isotropic) and gneiss (foliated) samples were performed on a Split Hopkinson Pressure Bar, equipped with high-speed photography. For the gneiss samples, the gneissic foliation was oriented (θ) at 0, 45 and 90° to the compression direction. Time-series images show the transient states of tensile rupture localization and propagation, leading to in situ fragmentation of the rocks. Granite samples produced a single incipient tensile rupture, accommodating pulverized clasts, whereas the gneisses underwent failure by way of major fracture and a network of secondary tensile fractures, forming large elongate clasts. For gneisses, θ greatly influenced the secondary crack growth, forcing propagation trajectories to orient preferentially either along or across the foliation. The two types of target rocks produced contrasting clast geometry in the fracture zones. The granite had mostly small clasts (<10 mm), with average aspect ratios around 1:2, whereas the gneisses produced larger clasts (<40 mm) with aspect ratios, 1:5, 1:4 and 1:4 for θ = 0, 45 and 90°, respectively. This study demonstrates that monomict breccia dikes could form in situ, rather than by a tensile dilation followed by infilling. © 2020 Elsevier Ltd 2020 10.1016/j.jsg.2020.104148 Journal of Structural Geology 140 Department of Earth Sciences, IIT, Kanpur, Uttar Pradesh 208016, India; Department of Mechanical Engineering, IIT, Kanpur, Uttar Pradesh 208016, India; Department of Geological Sciences, Jadavpur University, Kolkata, 700032, India https://www.scopus.com/inward/record.uri?eid=2-s2.0-85089277522&doi=10.1016%2fj.jsg.2020.104148&partnerID=40&md5=368e1a1b5744e99f331f95fc4b335b4d cited By 1 B.J. Jacob S. Misra V. Parameswaran N. Mandal article Lied20201707 Tephra layers of the Mýtina Maar, Czech Republic, contain ferrimagnetic Mg–Al-rich titanomagnetite, which is suggested to originate from a fractionated alkaline CO2-rich lithospheric mantle melt. We investigated the magnetic mineralogy and Curie temperature (TC) from tephra deposits of two drill cores (< 9 m depth). TC calculated (208 ± 14 °C) from chemical composition (Fe2+0.8Mg0.5Fe3+1.1Al0.3Ti0.3O4) is in accordance with TC retrieved from cooling curves of temperature-dependent magnetic susceptibility measurements (195–232 °C). However, thermomagnetic curves are irreversible either with lower (type I) or higher (type II) TC in the heating curve. All curves show transition temperatures above ca. 390 °C, indicating maghemitization. We interpret the irreversibility of TC (∆TC) in terms of different degrees of cation ordering, overprinted or masked by different degrees of maghemitization, which is a low-temperature phenomenon. Negative ∆TC indicates that original deposited titanomagnetite has cooled faster and, therefore, has stored a lower degree of cation ordering compared to heating/cooling rate of 11 °C/min in the Kappabridge. Type II with positive ∆TC indicates higher degree of cation ordering, and, therefore, slower cooling rate. The central part of this deposit shows most severe maghemitization, indicating rather wet emplacement. We, therefore, suggest different eruption styles for deposition of type I pyroclastics with more phreatomagmatic and type II pyroclastics with more phreato-Strombolian eruption styles. Our study is a new approach to discriminate different cooling histories in maar deposits using the Curie temperature of titanomagnetite. We suggest that this method has the potential to discriminate different emplacement modes resulting from different eruption styles. © 2020, The Author(s). Article 2020 English 14373254 10.1007/s00531-020-01865-1 International Journal of Earth Sciences 109 Springer 1707 – 1725 5 Czech Republic; cooling; emplacement; mineral alteration; Pleistocene; pyroclastic deposit; tephra; volcanic eruption https://www.scopus.com/inward/record.uri?eid=2-s2.0-85084602885&doi=10.1007%2fs00531-020-01865-1&partnerID=40&md5=10681e60eb46f6b7fdac734d61a97678 Cited by: 6; All Open Access, Green Open Access, Hybrid Gold Open Access Philipp Lied Agnes Kontny Norbert Nowaczyk Jan Mrlina Horst Kämpf article kastner_correlation_2020 {\textless}p{\textgreater}{\textless}strong{\textgreater}Abstract.{\textless}/strong{\textgreater} Deeply rooted thrust zones are key features of tectonic processes and the evolution of mountain belts. Exhumed and deeply eroded orogens like the Scandinavian Caledonides allow us to study such systems from the surface. Previous seismic investigations of the Seve Nappe Complex have shown indications of a strong but discontinuous reflectivity of this thrust zone, which is only poorly understood. The correlation of seismic properties measured on borehole cores with surface seismic data can constrain the origin of this reflectivity. To this end, we compare seismic velocities measured on cores to in situ velocities measured in the borehole. For some intervals of the COSC-1 borehole, the core and downhole velocities deviate by up to 2&thinsp;km&thinsp;s{\textless}span class="inline-formula"{\textgreater}$^{\textrm{−1}}${\textless}/span{\textgreater}. These differences in the core and downhole velocities are most likely the result of microcracks mainly due to depressurization. However, the core and downhole velocities of the intervals with mafic rocks are generally in close agreement. Seismic anisotropy measured in laboratory samples increases from about 5&thinsp;% to 26&thinsp;% at depth, correlating with a transition from gneissic to schistose foliation. Thus, metamorphic foliation has a clear expression in seismic anisotropy. These results will aid in the evaluation of core-derived seismic properties of high-grade metamorphic rocks at the COSC-1 borehole and elsewhere.{\textless}/p{\textgreater} 2020 apr English 1869-9510 https://doi.org/10.5194/se-11-607-2020 Solid Earth 11 607--626 2 https://se.copernicus.org/articles/11/607/2020/ Publisher: Copernicus GmbH Felix Kästner Simona Pierdominici Judith Elger Alba Zappone Jochem Kück Christian Berndt techreport guglielmi_crystalline_2020 Within the Spent Fuel & Waste Science and Technology (SFWST) Program, research work continues further with the goal to better understand long-term performance of disposal systems in three main geologic rock types: clay/shale, salt, and crystalline rock. This report documents LBNL’s research activities related to investigations of crystalline host rock according to the scope of two work packages: SF-20LB01030207 “Crystalline International Collaborations – LBNL,” and SF-20LB01030203 “Crystalline Disposal R&D – LBNL.” These research activities correspond are related to key Features, Events, and Processes (FEPs), ranked in importance from medium to high, as listed in Table 7 of the Used Fuel Disposition Campaign Disposal Research and Development Roadmap (FCR&D-USED-2011-000065 REV0) (Nutt, 2011). Specifically, these research activities address FEP 2.2.01, Excavation Disturbed Zone (EZD). The results of these research activities provide important insights into understanding and predicting flow and transport processes that could occur in low-permeability crystalline rocks, in which fractures might serve as main conduits for fluid flow and radionuclide transport. The evolution of the EDZ during the excavation of the tunnel as well as the evolution of microcrack growth within the EDZ after the emplacement of backfill are critical for predicting the long- term behavior of the EDZ. A number of factors including stress, temperature, water activity, capillary pressure, chemistry, and mineralogy can affect the rock evolution, which require advanced experimental tools to study it. 2020 jul English 10.2172/1642697 Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States) LBNL-2001334 https://doi.org/10.2172/1642697 Yves Guglielmi Chun Chang Paul Cook Patrick Dobson Florian Soom Seiji Nakagawa Auli Niemi Chris Juhlin Henning Lorenz Jan-Erik Rosberg Benoît Dessirier Chinfu Tsang Alexandru Tatomir Farzad Basirat Emil Lundberg Bjarne Almqvist Sharon Borglin Christine Doughty Lian Zheng article Wilke2020 The scarcity of high-resolution empirical data directly tracking diversity over time limits our understanding of speciation and extinction dynamics and the drivers of rate changes. Here, we analyze a continuous species-level fossil record of endemic diatoms from ancient Lake Ohrid, along with environmental and climate indicator time series since lake formation 1.36 million years (Ma) ago. We show that speciation and extinction rates nearly simultaneously decreased in the environmentally dynamic phase after ecosystem formation and stabilized after deep-water conditions established in Lake Ohrid. As the lake deepens, we also see a switch in the macroevolutionary trade-off, resulting in a transition from a volatile assemblage of short-lived endemic species to a stable community of long-lived species. Our results emphasize the importance of the interplay between environmental/climate change, ecosystem stability, and environmental limits to diversity for diversification processes. The study also provides a new understanding of evolutionary dynamics in long-lived ecosystems. © 2020 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution NonCommercial License 4.0 (CC BY-NC). Article 2020 English 23752548 10.1126/sciadv.abb2943 Science Advances 6 American Association for the Advancement of Science 40 Biodiversity; Biological Evolution; Climate Change; Ecosystem; Fossils; Lakes; Dynamics; Economic and social effects; Lakes; Climate indicators; Ecosystem stability; Empirical data; Endemic species; Evolutionary dynamics; Extinction rates; High resolution; Lake formation; biodiversity; climate change; ecosystem; evolution; fossil; lake; Ecosystems https://www.scopus.com/inward/record.uri?eid=2-s2.0-85092477633&doi=10.1126%2fsciadv.abb2943&partnerID=40&md5=5d50ed0b0f58a70615f54f6c765b3240 Cited by: 18; All Open Access, Gold Open Access, Green Open Access Thomas Wilke Torsten Hauffe Elena Jovanovska Aleksandra Cvetkoska Timme Donders Klemens Ekschmitt Alexander Francke Jack H. Lacey Zlatko Levkov Charles R. Marshall Thomas A. Neubauer Daniele Silvestro Björn Stelbrink Hendrik Vogel Christian Albrecht Jens Holtvoeth Sebastian Krastel Niklas Leicher Melanie J. Leng Katja Lindhorst Alessia Masi Nadja Ognjanova-Rumenova Konstantinos Panagiotopoulos Jane M. Reed Laura Sadori Slavica Tofilovska Bert Van Bocxlaer Friederike Wagner-Cremer Frank P. Wesselingh Volkmar Wolters Giovanni Zanchetta Xiaosen Zhang Bernd Wagner article Francke2020 Article 2020 10.1016/j.chemgeo.2020.119698 Chemical Geology 550 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85086371127&doi=10.1016%2fj.chemgeo.2020.119698&partnerID=40&md5=621d4199eec4c7c8d6553b0da15a6fd1 Cited by: 14 Alexander Francke Anthony Dosseto Janna Just Bernd Wagner Brian G. Jones article Gupta2020 2020 English 13884360 10.1007/978-3-030-10475-7_15-1 Encyclopedia of Earth Sciences Series PartF4 Springer Science and Business Media B.V. National Geophysical Research Institute, Council of Scientific & Industrial Research, Hyderabad, India https://www.scopus.com/inward/record.uri?eid=2-s2.0-85133329403&doi=10.1007%2f978-3-030-10475-7_15-1&partnerID=40&md5=9a5f8cc0fcc94784899eacfd9dbaf0f3 cited By 0 H. Gupta article Liu202079 The working environment in hot dry rock boreholes, encountered in deep geothermal investigation drilling and ultra-deep geological drilling (up to 5000 m), is very difficult at the present stage. We have developed a drilling trajectory measuring instrumentation (DTMI), which is based on the interference fiber-optic gyro (FOG). This can work continuously, for 4 h, in an environment where the ambient temperature does not exceed 270 °C and the pressure does not exceed 120MPa. The DTMI is mainly divided into three parts: an external confining tube, a metal vacuum flask, and a FOG measurement probe. Here, we focus on the mechanical design, strength, and pressure field simulation analysis for the external tube, the structural design and temperature field simulation analysis for the vacuum flask, and the FOG Shupe error analysis and compensation in the temperature field. Finally, through the engineering applications of the SK-2 east borehole of the China Continental Scientific Drilling (CCSD) project and the geothermal well of Xingreguan-2, the data measurements of the drilling trajectory were used to analyze the stability of the DTMI. The instrument realizes long-duration, high-stability work in the process of making trajectory measurements in an ultra-deep hole. The instrument has the characteristic of anti-electromagnetic interference and enables work to be carried out in the blind zone of existing technologies and instrumentation. Therefore, DTMI has great potential in the promotion and development of geological drilling technology. © Author(s) 2020. 2020 English 21930856 10.5194/gi-9-79-2020 Geoscientific Instrumentation, Methods and Data Systems 9 Copernicus GmbH 79-104 Institute of Crustal Dyanmics, CEA, Beijing, 100085, China; School of Manufacturing Science and Engineering, Sichuan University, Chengdu, 610065, China; Institute of Exploration Technology of CAGS, Chengdu, 611730, China 1 Boreholes; Bottles; Electromagnetic pulse; Error compensation; Geology; Geothermal wells; Gyroscopes; Hot working; Infill drilling; Structural design; Temperature; Trajectories, Continental scientific drillings; Data measurements; Design and application; Engineering applications; Geological drilling; Temperature field simulation; Trajectory measurements; Working environment, Fiber optics, borehole geophysics; design method; drilling; fiber optics; geological survey; geothermal system; hot dry rock; instrumentation; measurement method; trajectory; well logging https://www.scopus.com/inward/record.uri?eid=2-s2.0-85082403416&doi=10.5194%2fgi-9-79-2020&partnerID=40&md5=9c8aea60b6587921000971b7bc4a9a2e cited By 1 Y. Liu C. Wang G. Luo W. Ji article Huang20201464 In the deep oil and gas drilling operations, estimation and prediction of the rheological properties for a drilling fluid are of crucial importance for precisely hydraulic calculating, cuttings carrying and wellbore stability controlling. Unfortunately, the existing well-known rheological models, such as Bingham Plastic, Power Law, Casson, and Herschel–Bulkley models neglect the effect of temperature on the apparent viscosity of water-based drilling fluid. In this paper, the rheological behavior of the poly-sulfonated drilling fluid applied to the Well SK-2 in Songliao basin, China, within a temperature range of 60–240°C, were experimentally determined using a FANN 50SL rheometer. Results showed that the apparent viscosity decreases with the increase of temperature, especially at the low shear rates. In the whole shear rate range, the rheology curve was divided into two parts. At low shear rates (&lt;170.3 s−1), the Herschel Bulkley model fitted well with the measured data, while at higher shear rates (&gt;170.3 s−1), the Bingham Plastic model got higher precision. Based on the viscosity equation recommended by the American Petroleum Institute, the temperature factor was introduced to modify the Herschel-Bulkley equation, and the apparent viscosity can be successfully predicted compared with the other commonly used rheological models. © 2019, © 2019 Taylor & Francis Group, LLC. 2020 English 15567036 10.1080/15567036.2019.1604861 Energy Sources, Part A: Recovery, Utilization and Environmental Effects 42 Taylor and Francis Inc. 1464-1475 College of Geoscience and Surveying Engineering, China University of Mining & Technology, Beijing, China; Remote sensing applied research laboratory, Chongqing Institute of Geology and Mineral Resources, Chongqing, China; School of Engineering, China University of Geosciences, Wuhan, China 12 Drilling fluids; Infill drilling; Oil wells; Rheology; Viscosity, American Petroleum Institute; Estimation and predictions; Herschel-Bulkley equations; High temperature; Modifying factors; Prediction model; Rheological property; Water based drilling fluids, Shear deformation https://www.scopus.com/inward/record.uri?eid=2-s2.0-85064486183&doi=10.1080%2f15567036.2019.1604861&partnerID=40&md5=67097a3a8cba130cf155741a86d34be1 cited By 15 Y. Huang W. Zheng D. Zhang Y. Xi article 10.1130/G46799.1 {The Chicxulub crater was formed by an asteroid impact at ca. 66 Ma. The impact is considered to have contributed to the end-Cretaceous mass extinction and reduced productivity in the world’s oceans due to a transient cessation of photosynthesis. Here, biomarker profiles extracted from crater core material reveal exceptional insights into the post-impact upheaval and rapid recovery of microbial life. In the immediate hours to days after the impact, ocean resurge flooded the crater and a subsequent tsunami delivered debris from the surrounding carbonate ramp. Deposited material, including biomarkers diagnostic for land plants, cyanobacteria, and photosynthetic sulfur bacteria, appears to have been mobilized by wave energy from coastal microbial mats. As that energy subsided, days to months later, blooms of unicellular cyanobacteria were fueled by terrigenous nutrients. Approximately 200 k.y. later, the nutrient supply waned and the basin returned to oligotrophic conditions, as evident from N2-fixing cyanobacteria biomarkers. At 1 m.y. after impact, the abundance of photosynthetic sulfur bacteria supported the development of water-column photic zone euxinia within the crater.} 2020 01 0091-7613 10.1130/G46799.1 Geology 48 328-332 4 https://doi.org/10.1130/G46799.1 Bettina Schaefer Kliti Grice Marco J.L. Coolen Roger E. Summons Xingqian Cui Thorsten Bauersachs Lorenz Schwark Michael E. Böttcher Timothy J. Bralower Shelby L. Lyons Katherine H. Freeman Charles S. Cockell Joanna V. Morgan Michael T. Whalen Christopher M. Lowery Vivi Vajda article Qin2024168 Article 2020 10.3969/j.issn.1673-9736.2020.01.05 Global Geology 23 38-70 1 Y. Gao Y. Jiao P. Wang R. Cheng G. Wang article Yang20201006 In order to deepen the understanding of the vertical change rule of the deep shale gas in the Songke 2 Well, the authors selected the 3500~5700 m section of the Shahezi Formation to carry out the X-ray 3D Computed Tomography (CT) imaging experiment. X-ray CT scan was performed on 19 pieces of 2 cm-diameter columnar cores to obtain non-destructive core scan data, and a three-dimensional image spatial structure with a core resolution of up to 15 μm was established. The pore morphology structure and space of the reconstructed core pore model were analyzed by comparative study of spatial distribution and coordination number, statistics of the vertical distribution of sample porosity and connectivity. This experiment proves that the digital core data have high resolution and rich information. The gray value information reflects different components in the sample. The skeleton and minerals are high gray values, and the pores and cracks are low gray values. Studies have shown that areas with large equivalent pore diameters have high porosity, and areas with large coordination numbers have good connectivity. The vertical distribution of porosity and connectivity is consistent with traditional knowledge and can be verified with logging information. It is believed that the digital core can be used as an important auxiliary method for deep core research in the future. © 2020, Science Press. All right reserved. Article 2020 Chinese 16712552 Geological Bulletin of China 39 China Geological Survey 1006 – 1014 7 mudstone; paleoenvironment; porosity; rock mechanics; shale gas; source rock; three-dimensional modeling https://www.scopus.com/inward/record.uri?eid=2-s2.0-85090074047&partnerID=40&md5=f486b5d12240742f57dc6490225d054a Cited by: 1 Jin Yang Hesheng Hou Wei Fu Rui Guo Zongdong Pan Jiaodong Zhang Huitao Zhang article Stebich2020 Palaeoecological evidence of intra-Saalian warm stages in Central Europe, which was strongly affected by glacial and periglacial processes during the major Middle and Late Pleistocene cold periods, is ambiguous so far. Recently, the first continuous sedimentary sequence of Central Europe containing the Saalian complex (MIS 8–6) with the Eemian interglacial in stratigraphic superposition was recovered from the newly discovered Neualbenreuth Maar (NE-Bavaria). Here we present palynological results from this record allowing us to critically discuss the available biostratigraphical evidence of alternating intra-Saalian warm-cold intervals from Central Europe. The new pollen record from the Neualbenreuth Maar comprises a continuous record of vegetation and climate changes encompassing four warm stages and five cold periods. The dominance of cold and dry tolerant herbs and the sparse representation of pioneer trees and shrubs during most parts of the sequence indicate open landscapes of steppe to woody-steppe character typical of late Middle and Late Pleistocene glacial periods in Central Europe. The pollen assemblages of the warm stage in the upper part of the core clearly support its correlation with the Eemian interglacial. The three pre-Eemian warm stages represent terrestrial analogues of the marine isotope stages (MIS) 7e, 7c, and 7a. During each of these intervals forests were established, but the reduced abundances and lower diversity of thermophilous and sub-oceanic elements in comparison to the Eemian attest to a weak interglacial character. Each of these interglacials shows a similar vegetation succession and only minor differences in the vegetation composition. The intervening stadial periods represent a strong (MIS 7d) and a moderate (MIS 7b) climate deterioration, respectively. The vegetation and climate succession during the Saalian glacial-interglacial complex of Neualbenreuth is broadly in line with the respective palynological signature from the Velay record (French Massif Central) and the Hoogeveen interstadial (The Netherlands). In contrast, there is only limited correspondence with most pollen records from northern and southern Central Europe, which were hitherto classified as MIS 7. © 2020 Elsevier Ltd Article 2020 English 02773791 10.1016/j.quascirev.2020.106681 Quaternary Science Reviews 250 Elsevier Ltd Europe; Climate change; Deterioration; Stratigraphy; Vegetation; Climate deterioration; Marine isotope stages; Middle Pleistocene; Periglacial process; Sedimentary sequence; Sparse representation; Vegetation composition; Vegetation successions; allostratigraphy; Eemian; interglacial; interstadial; paleoecology; palynology; Pleistocene; Pliocene-Pleistocene boundary; Saalian; stratigraphy; Glacial geology https://www.scopus.com/inward/record.uri?eid=2-s2.0-85096179678&doi=10.1016%2fj.quascirev.2020.106681&partnerID=40&md5=3d41827b4e6348f9f1280a947c7cb21b Cited by: 4 Martina Stebich Dana Höfer Jens Mingram Norbert Nowaczyk Johann Rohrmüller Jan Mrlina Horst Kämpf article Shang2020236 The formation mechanism of the oil shale developed in the 1st and 2nd members of Nenjiang Formation in Songliao Basin was studied by combining theoretical model with geological data such as total carbon content, sulfur isotope of pyrite, and whole rock element from the Songke-1 Well (south hole). Some conclusions have been reached: (1) It may not be fully correct to attribute the formation of oil shale to seawater intrusion into the lake basin. Although seawater invasion can lead to salinization of the lake and subsequent algae blooming, the change of bottom water redox condition caused by the invasion of oxygen-rich seawater into the bottom lake can inhibit the accumulation and preservation of organic matter in sediments; (2) The impact of seawater transgression on oil shale formation was mainly related to algae blooming caused by the continuous salinization of the lake water after transgression; (3) Volcanic tuff deposits are widely distributed in the Songliao basin and usually associated with oil shale deposits. The increase of productivity in ancient Songliao lake basin was directly related to nutrients such as phosphorus and iron brought by volcanic ash input; (4) The formation of oil shale in the Nenjiang Formation was controlled by a combination of mechanisms such as water eutrophication events induced by instantaneous mass input of volcanic ash and seawater invasion. It is concluded that organic matter enrichment in the oil shale is controlled by both water depth and the influence of sediment input from rivers. © 2020 Editorial Board of Geology in China. All rights reserved. Article 2020 Chinese 10003657 10.12029/gc20200119 Geology in China 47 Science Press 236 – 248 1 China; Songliao Basin; enrichment; eutrophication; hydrocarbon exploration; model; oil shale; organic matter; volcanic ash https://www.scopus.com/inward/record.uri?eid=2-s2.0-85092893782&doi=10.12029%2fgc20200119&partnerID=40&md5=5d557689c76109526a08d4a9ff1f5d48 Cited by: 13 Fei Shang Haiyan Zhou Yong Liu Xuexian Zhou Lan Wang He Bi Guochang Wang Li Song Ruiqian Chen article Xiaojuan202027 A continuous terrestrial succession was recovered from the Songke-2 (SK-2) borehole in the Songliao Basin, Northeastern China. This borehole provides a unique material for further research on the continental paleoclimate during Cretaceous greenhouse period, following a series of achievements of the Songke-1 (SK-1) core. In this study, thorium (Th) logging data were chosen as a paleoclimate proxy to conduct a detailed cyclostratigraphic analysis. The Th series varies quasi-periodically; power spectra and evolutionary fast Fourier transformation (FFT) analysis reveal significant cycles in the Quantou (K2q), Qingshankou (K2qn), Yaojia (Ky and Nenjiang (K2n) formations. The ratio of cycle wavelengths in these stratigraphic units is approximately 20:5:2:1, corresponding to long orbital eccentricity (405 kyr), short orbital eccentricity (100 kyr), obliquity (37 kyr), and precession cycles (22.5 kyr and 18.4 kyr). The durations of the K2n, K2y, K2qn and K2q are estimated as 6.97, 1.83, 5.30 and 4.52 Myr, respectively, based on the constructed ∼18.62 Myr “floating” astronomical time scale (ATS). Comparison of the durations between the SK-1 s and SK-2 boreholes exhibits a slight difference of 0.06 Myr and 0.459 Myr for K2qn and K2y. Nevertheless, our ATS of K2n supports the chronostratigraphic frame constructed by the CA-ID-TIMS data of the SK-1s borehole. This new “floating” ATS provides precise numerical ages for stratigraphic boundaries, biozones and geological events in the Songliao Basin, and can serve as a basis for correlation of strata and events between marine and terrestrial systems. © 2020 Geological Society of China 2020 English 10009515 10.1111/1755-6724.14497 Acta Geologica Sinica (English Edition) 94 John Wiley and Sons Inc 27-37 School of Ocean Sciences, China University of Geosciences, Beijing, 100083, China; State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing, 100083, China 1 borehole; Cretaceous; detection method; eccentricity; marine environment; paleoclimate; proxy climate record; terrestrial environment; thorium, China; Songliao Basin https://www.scopus.com/inward/record.uri?eid=2-s2.0-85083282420&doi=10.1111%2f1755-6724.14497&partnerID=40&md5=c0b89798bc66b453309834d97a1ca837 cited By 3 M.A. Xiaojuan W.U. Huaichun Q. Fang M. Shi S. Zhang T. Yang L.I. Haiyan C. Wang article Collins2020 The environmental severity of large impacts on Earth is influenced by their impact trajectory. Impact direction and angle to the target plane affect the volume and depth of origin of vaporized target, as well as the trajectories of ejected material. The asteroid impact that formed the 66 Ma Chicxulub crater had a profound and catastrophic effect on Earth’s environment, but the impact trajectory is debated. Here we show that impact angle and direction can be diagnosed by asymmetries in the subsurface structure of the Chicxulub crater. Comparison of 3D numerical simulations of Chicxulub-scale impacts with geophysical observations suggests that the Chicxulub crater was formed by a steeply-inclined (45–60° to horizontal) impact from the northeast; several lines of evidence rule out a low angle (<30°) impact. A steeply-inclined impact produces a nearly symmetric distribution of ejected rock and releases more climate-changing gases per impactor mass than either a very shallow or near-vertical impact. © 2020, The Author(s). 2020 10.1038/s41467-020-15269-x Nature Communications 11 Department Earth Science and Engineering, Imperial College London, London, SW7 2AZ, United Kingdom; Institute of Geology, University of Freiburg, Freiburg, 79104, Germany; Institute for Geophysics and Department of Geological Sciences, University of Texas at Austin, Austin, TX 78758, United States; Institute for Geophysics, University of Texas at Austin, Austin, TX, United States; Laboratoire GeoRessources, Université de Lorraine, Vandoeuvre-lés-Nancy, France; Analytical, Environmental and Geochemistry, Vrije Universiteit Brussel, Brussels, Belgium; UK Centre for Astrobiology, School of Physics and Astronomy, University of Edinburgh, Edinburgh, United Kingdom; Western Australia Organic and Isotope Geochemistry Centre, School of Earth and Planetary Sciences, Curtin University, Bentley, WA 6102, Australia; Natural History Museum, Vienna, Austria; Alfred Wegener Institute Helmholtz Centre of Polar and Marine Research, Bremerhaven, Germany; Department of Earth and Planetary Science, University of Tokyo, Tokyo, Japan; Department of Geosciences, Pennsylvania State University, University Park, PA, United States; Lunar and Planetary Institute, Houston, TX, United States; Géosciences Montpellier, CNRS, Université de Montpellier, Montpellier, France; Groupe de Physico-Chimie de l’Atmosphère, L’Institut de Chimie et Procédés pour l’Énergie, l’Environnement et la Santé, Université de Strasbourg, Strasbourg, France; Instituto de Geofísica, Universidad Nacional Autónoma De México, Ciudad De México, Mexico; School of Geographical and Earth Sciences, University of Glasgow, Glasgow, United Kingdom; Argon Isotope Facility, Scottish Universities Environmental Research Centre, East Kilbride, United Kingdom; Department of Geology and Geophysics, University of Utah, Salt Lake City, UT, United States; Unidad de Ciencias del Agua, Mérida, Mexico; Institut für Geologie, Universität Hamburg, Hamburg, Germany; Japan Agency for Marine-Earth Science and Technology, Kanagawa, Japan; Faculty of Earth and Life Sciences, Vrije Universiteit Amsterdam, Amsterdam, Netherlands; Department of Earth and Planetary Sciences, Rutgers University, Piscataway Township, NJ, United States; Department of Geophysics, Stanford University, Stanford, CA, United States; Kochi Institute for Core Sample Research, Japan Agency for Marine-Earth Science and Technology, Kochi, Japan; Department of Geosciences, University of Alaska Fairbanks, Fairbanks, AK, United States; Eyring Materials Center, Arizona State University, Tempe, AZ, United States; School of Earth Sciences, Planetary Science Institute, China University of Geosciences, Wuhan, China; Department of Chemistry, Toho University, Funabashi, Chiba, Japan; NASA Astrobiology Institute, Mountain View, CA, United States; Planetary Science Institute, Tucson, AZ, United States 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85085513257&doi=10.1038%2fs41467-020-15269-x&partnerID=40&md5=6b7520fd50e30e75f10f8f3affe95b2b cited By 40 G.S. Collins N. Patel T.M. Davison A.S.P. Rae J.V. Morgan S.P.S. Gulick G.L. Christeson E. Chenot P. Claeys C.S. Cockell M.J.L. Coolen L. Ferrière C. Gebhardt K. Goto H. Jones D.A. Kring J. Lofi C.M. Lowery R. Ocampo-Torres L. Pérez-Cruz A.E. Pickersgill M.H. Poelchau C. Rasmussen M. Rebolledo-Vieyra U. Riller H. Sato J. Smit S.M. Tikoo N. Tomioka J. Urrutia-Fucugauchi M.T. Whalen A. Wittmann L. Xiao K.E. Yamaguchi N. Artemieva T.J. Bralower IODP-ICDP Expedition 364 Science Party Third-Party Scientists article Woods2020 Abrupt warming events recorded in Greenland ice cores known as Dansgaard-Oeschger (DO) interstadials are linked to changes in tropical circulation during the last glacial cycle. Corresponding variations in South American summer monsoon (SASM) strength are documented, most commonly, in isotopic records from speleothems, but less is known about how these changes affected precipitation and Andean glacier mass balance. Here we present a sediment record spanning the last ~50 ka from Lake Junín (Peru) in the tropical Andes that has sufficient chronologic precision to document abrupt climatic events on a centennial-millennial time scale. DO events involved the near-complete disappearance of glaciers below 4700 masl in the eastern Andean cordillera and major reductions in the level of Peru’s second largest lake. Our results reveal the magnitude of the hydroclimatic disruptions in the highest reaches of the Amazon Basin that were caused by a weakening of the SASM during abrupt arctic warming. Accentuated warming in the Arctic could lead to significant reductions in the precipitation-evaporation balance of the southern tropical Andes with deleterious effects on this densely populated region of South America. © 2020, The Author(s). Article 2020 English 20411723 10.1038/s41467-020-19000-8 Nature Communications 11 Nature Research 1 Amazon Basin; Andes; Arctic; Greenland; Peru; cordillera; Dansgaard-Oeschger cycle; drought stress; glacier retreat; hydrometeorology; Last Glacial; monsoon; precipitation assessment; seasonality; Arctic; article; deglaciation; drought; evaporation; glacial period; Greenland; Peru; precipitation; sediment; summer; warming https://www.scopus.com/inward/record.uri?eid=2-s2.0-85092453814&doi=10.1038%2fs41467-020-19000-8&partnerID=40&md5=18b87956157dad37f021d9738d15d372 Cited by: 5; All Open Access, Gold Open Access, Green Open Access Arielle Woods Donald T. Rodbell Mark B. Abbott Robert G. Hatfield Christine Y. Chen Sophie B. Lehmann David McGee Nicholas C. Weidhaas Pedro M. Tapia Blas L. Valero-Garcés Mark B. Bush Joseph S. Stoner inproceedings chiaraluce2020strainmeter 2020 EGU General Assembly Conference Abstracts 19792 Lauro Chiaraluce Rick Bennett David Mencin Massimiliano Barchi Marco Bohnhoff article Pan2020 Good knowledge of hydrate morphology and accurate quantification of hydrate saturation are significant for reservoir characterization, resource exploitation and geohazards assessment. Although many of empirical or theoretical models have been developed to detect hydrate morphology and predict hydrate saturation from elastic-wave velocities, they either fail to hold true for complex morphologies or cannot provide accurate hydrate saturation estimate. In this study, we propose a unified contact cementation theory by applying the modified Hashin-Shtrikman upper and lower bounds to an extended cementation theory. By merging the cementation theory and effective medium theory, it can be used to account for four types of hydrate morphologies. Numerical modeling results provide some new insights into effects of normalized thickness of hydrate layer, friction coefficient and effective pressure on elastic-wave velocities for different morphologies, which will be helpful for analyzing the borehole stability and determining optimum production-related strategies. In addition, we propose a hydrate morphology-based inversion method by introducing the ratio of multiple hydrate morphologies from statistical analyses and apply it to the acoustic logs from the Mallik 5L-38 permafrost-related gas hydrate research well in Mackenzie Delta and other three marine wells in Nankai Trough and Hikurangi margin. The velocity-based gas hydrate saturation estimations are in good agreement with those predicted from resistivity log and Nuclear Magnetic Resonance measurement, as well as core data, confirming feasibility and applicability of our theory and inversion method, and indicating its potential in seismic characterization of gas hydrate reservoirs. © 2019 Elsevier Ltd 2020 English 02648172 10.1016/j.marpetgeo.2019.104146 Marine and Petroleum Geology 113 Elsevier Ltd Research Institute of Petroleum Exploration and Development, Beijing, 100083, China; Department of Geosciences, University of Tulsa, Tulsa, OK 74104, United States; Beijing Research Institute of Uranium Geology, Beijing, 100029, China; Research Institute of China National Offshore Oil Corporation, Beijing, China; Research Institute of Petroleum Exploration and Development of Huabei Oil Field Company, Renqiu, Hebei 062552, China Acoustic logging; Acoustics; Boreholes; Cementing (shafts); Elastic waves; Electric logging; Friction; Gases; Hydration; Morphology; Nuclear magnetic logging; Velocity, Accurate quantifications; Effective medium theories; Elastic wave velocity; Gas hydrate saturations; Hikurangi margin; Hydrate saturation; Reservoir characterization; Unified contact cementation theory, Gas hydrates, detection method; elastic wave; estimation method; gas hydrate; hydrocarbon exploration; hydrocarbon reservoir; morphology; wave velocity https://www.scopus.com/inward/record.uri?eid=2-s2.0-85076162705&doi=10.1016%2fj.marpetgeo.2019.104146&partnerID=40&md5=4d0ce5f1ee11d2d92d7e47d33c91ab80 cited By 12 H. Pan H. Li J. Chen Y. Zhang S. Cai Y. Huang Y. Zheng Y. Zhao J. Deng article Lupien2020 Article 2020 10.1016/j.quascirev.2020.106531 Quaternary Science Reviews 245 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85089363020&doi=10.1016%2fj.quascirev.2020.106531&partnerID=40&md5=249aa2eb40d3dfab6cb36c2d9f741875 Cited by: 24 Rachel L. Lupien James M. Russell Matt Grove Catherine C. Beck Craig S. Feibel Andrew S. Cohen article Jeppson2020 Article 2020 10.1016/j.tecto.2020.228410 Tectonophysics 781 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85082169908&doi=10.1016%2fj.tecto.2020.228410&partnerID=40&md5=b1cb6164da0958a35c7436d6165539c4 Cited by: 3 Tamara N. Jeppson Harold Tobin article prause2020alteration 2020 10.1016/j.jvolgeores.2019.106754 Journal of Volcanology and Geothermal Research 392 Elsevier 106754 Simon Prause Tobias Björn Weisenberger Piergiulio Cappelletti Carla Grimaldi Concetta Rispoli Kristján Jónasson Marie D Jackson Magnús Tumi Gudmundsson article Liu2020 Article 2020 10.1016/j.palaeo.2019.109555 Palaeogeography, Palaeoclimatology, Palaeoecology 541 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85077389114&doi=10.1016%2fj.palaeo.2019.109555&partnerID=40&md5=d80f73a9d8353ec6964bd7f1ca399cd7 Cited by: 15 Wei Liu Huaichun Wu Linda A. Hinnov M'bark Baddouh Pujun Wang Youfeng Gao Shihong Zhang Tianshui Yang Haiyan Li Chengshan Wang article Hu2020254 In order to solve the problem of the high mud content and easy hydration and dispersion of the Cretaceous sedimentary strata in well Songke-2, the bit balling is prone to occur in the water-based drilling fluid environment, which affects the drill bit ROP and induces downhole adhesion stuck, the paper combined the core drilling technology of well Songke-2, systematically analyzed of the causes of bit balling generated by the drill bit in the mudstone and water-based drilling fluid environment, provided a basis for the design of the anti-balling of the drill bit and the formulation of the anti-ball in drilling fluid, and proposed a drilling fluid formulation with excellent anti-balling performance. The results show that the mudstone drilled in well Songke-2 had the characteristics of high shale content and easy hydration and viscosity, it is very easy to induce the bit balling caused by the adhesion of cuttings and the mechanical “inlaying” of cuttings. Mechanical adhesion of drill bit and drill structure size, bottom hole hydraulic condition, bit material and surface condition, drilling procedure parameters and drilling fluid performance indicators are closely related. Adjusting the performance of the drilling fluid is an effective way to solve the bit balling problem at the drilling site. According to the technical characteristics of the high-temperature and high-pressure sections in the fourth opening of the well Songke-2,after repeated matching, the drilling fluid composition with excellent high temperature resistance and anti-adhesion performance was obtained. The test results of high temperature inhibition, water loss wall-building and the lubricity show that this drilling fluid has strong inhibition at high temperature(230℃), little water loss and good lubricity, it can solve the bit balling problem of the well Songke-2, effectively avoid the instability of the ROP and the occurrence of sticking stuck, the field application effect is ideal. © Meitiandizhi Yu Kantan/Coal Geology and Exploration 2020. Article 2020 Chinese 10011986 10.3969/j.issn.1001-1986.2020.05.032 Meitiandizhi Yu Kantan/Coal Geology and Exploration 48 Science Press 254 – 261+268 5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85113326859&doi=10.3969%2fj.issn.1001-1986.2020.05.032&partnerID=40&md5=b1110ff860bba89ba265e182e3664886 Cited by: 3 Yule Hu Chen Hu Hengchun Zhang Wenlong Zheng article Harms2020 2020 10.1007/978-3-030-10475-7_195-1 Encyclopedia of Earth Sciences Series PartF4 Scientific Drilling, German Research Centre for Geosciences GFZ, Potsdam, Germany; Department of Earth and Space Sciences, University of Washington, Seattle, WA, United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-85133938650&doi=10.1007%2f978-3-030-10475-7_195-1&partnerID=40&md5=e6fbf8ccf08e216e65cd1d69f73ab68d cited By 0 U. Harms H. Tobin article Prudencio20201677 Unrest at Long Valley caldera (California) during the past few decades has been attributed to the ascent of hydrothermal fluids or magma recharge. The difference is critical for assessing volcanic hazard. To better constrain subsurface structures in the upper crust and to help distinguish between these two competing hypotheses for the origin of unrest, we model the 3-D seismic attenuation structure because attenuation is particularly sensitive to the presence of melt. We analyse more than 47 000 vertical component waveforms recorded from January 2000 through November 2016 obtained from the Northern California Earthquake Data Center. We then inverted the S-to-coda energy ratios using the coda normalization method and obtained an average Q of 250. Low attenuation anomalies are imaged in the fluid-rich western and eastern areas of the caldera, one of which corresponds to the location of an earthquake swarm that occurred in 2014. From a comparison with other geophysical images (magnetotellurics, seismic tomography) we attribute the high attenuation anomalies to hydrothermal systems. Average to high attenuation values are also observed at Mammoth Mountain (southwest of the caldera), and may also have a hydrothermal origin. A large high attenuation anomaly within the caldera extends from the surface to the depths we can resolve at 9 km. Shallow rocks here are cold and this is where earthquakes occur. Together, these observations imply that the high attenuation region is not imaging a large magma body at shallow depths nor do we image any isolated high attenuation bodies in the upper ≈8 km that would be clear-cut evidence for partially molten bodies such as sills or other magma bodies. © 2019 The Author(s). Published by Oxford University Press on behalf of The Royal Astronomical Society. 2020 English 0956540X 10.1093/gji/ggz543 Geophysical Journal International 220 Oxford University Press 1677-1686 Department of Theoretical Physics and Cosmos Physics of the Earth Area, University of Granada, Profesor Clavera 12, Granada, 18071, Spain; Instituto Andaluz de Geofisica, University of Granada, Campus de Cartuja, Granada, Spain; Department of Earth and Planetary Science, University of California at Berkeley, 307 McCone Hall, Berkeley, CA 94720, United States; Berkeley Seismological Laboratory, University of California-Berkeley, 215 McCone Hall, Berkeley, CA 94720, United States 3 Landforms, Coda normalization method; Hydrothermal fluids; Hydrothermal system; Long valley caldera; Seismic attenuation; Seismic tomography; Subsurface structures; Vertical component, Earthquakes, caldera; crustal structure; earthquake event; earthquake magnitude; magma; seismic attenuation; seismic data; seismic source; seismicity; seismology; three-dimensional modeling; waveform analysis, California; Long Valley Caldera; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-85086011570&doi=10.1093%2fgji%2fggz543&partnerID=40&md5=fa91cac2cf82241fc7e2dcd81b931fef cited By 8 J. Prudencio M. Manga article Eichelberger20201 Article 2020 10.3390/geosciences10060212 Geosciences (Switzerland) 10 1 – 26 6 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85086126902&doi=10.3390%2fgeosciences10060212&partnerID=40&md5=68c2c001c338419e57723d70acc2619c Cited by: 21; All Open Access, Gold Open Access, Green Open Access John Eichelberger article Simpson2020 The 66 Ma, ∼180 km Chicxulub impact structure in the northern Yucatán peninsula and southern Gulf of Mexico is the best-preserved large impact crater on Earth with a well-developed peak ring. The most recent drilling campaign took place offshore during the joint International Ocean Discovery Program – International Continental Scientific Drilling Program (IODP–ICDP) Expedition 364 at site M0077A (21.45°N, 89.95°W) and recovered ∼830 m of continuous core. Initial examination revealed that the peak-ring comprises four main lithological units (from the base upwards): crystalline basement granitoid rocks (Unit 4); a thin layer of impact melt rocks (Units 3A and B); melt-bearing breccias (Units 2A–C); and post-impact sedimentary rocks (Unit 1). Preliminary analysis of the drill core indicated that hydrothermal alteration has affected all lithologies and is especially pervasive in the melt-bearing breccias of Unit 2 (721.6 to 617.33 meters below sea floor, mbsf). Here we present the first detailed investigation of hydrothermal alteration within the melt-bearing breccias. Alteration phases are predominantly Fe-Mg clay minerals, zeolites, alkali feldspars, calcite and minor sulfides, sulfates, opal and Fe-Ti oxides. Alteration is especially intense proximal to lithologic contacts, particularly at the base of subunit 2B where there is an abrupt increase in host rock porosity ∼30 m above the impact melt rocks. The pervasiveness of clay minerals and zeolites is attributed to the high amounts of devitrified silicate glass throughout Unit 2. The phases preserved here are consistent with the findings of previous hydrothermal studies in other areas of the Chicxulub structure, and suggest an evolving water-rock system that was alkaline-saline, comparable to seawater-volcanic glass alteration. © 2020 Elsevier B.V. 2020 10.1016/j.epsl.2020.116425 Earth and Planetary Science Letters 547 Department of Earth Sciences, Institute for Earth and Space Exploration, The University of Western OntarioON N6A 3K7, Canada; Lunar and Planetary Institute, Universities Space Research Association, Houston, TX 77058, United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-85088226608&doi=10.1016%2fj.epsl.2020.116425&partnerID=40&md5=4fe32f301e3861274f69391e1e6510de cited By 16 S.L. Simpson G.R. Osinski F.J. Longstaffe M. Schmieder D.A. Kring article Warnke2020 Density-driven mass movement deposits (MMDs) were mapped throughout the Quaternary sedimentary record of Lake El'gygytgyn (NE Siberia) using high-resolution acoustic data. Three different acoustic facies types were identified in the lake: (1) pelagic sediment, (2) plastic flow deposits and (3) turbidites. Deposits from plastic flows are dominantly present proximal to the lakes' slopes, whereas deposits from turbidity currents occur more spatially distributed. During glacial times, the distribution of MMDs was more uniform, while during interglacial periods, MMDs were deposited predominantly close to the slope of the northwestern area. Furthermore, the overall number of MMDs and accumulated sediment volume significantly varies between glacial/interglacial periods. About 1.6 times more MMDs were mapped during interglacials, contributing to a 3.5 times higher sediment volume. The main reason for this large difference is that a significant increase in plastic flows were formed during interglacials, which account for a much larger volume of sediments when compared with the glacial intervals characterized by increased amount of turbidites. It appears that the most important source areas for MMDs are located at the northern and western shores. Cycles of lake level changes caused by variations in climate conditions between glacials and interglacials are likely the main trigger mechanism for the generation of these MMDs. The climate-dependent genesis and partly erosive potential influencing the sedimentary record contain implications to consider for future paleo-environmental reconstructions in lacustrine settings. © 2019 Elsevier B.V. 2020 English 00310182 10.1016/j.palaeo.2019.109506 Palaeogeography, Palaeoclimatology, Palaeoecology 539 Elsevier B.V. Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Am Alten Hafen 26, Bremerhaven, 27515, Germany glacial-interglacial cycle; lacustrine deposit; lake level; mass movement; paleoclimate; paleoenvironment; Quaternary; reconstruction; slope failure; turbidity current, Chukchi; Elgygytgyn Lake; Russian Federation; Siberia https://www.scopus.com/inward/record.uri?eid=2-s2.0-85076180047&doi=10.1016%2fj.palaeo.2019.109506&partnerID=40&md5=568cf4993e895282aece7958253524ca cited By 0 F. Warnke C. Gebhardt F. Niessen article lods2020groundwater 2020 Journal of Hydrology 589 Elsevier 125152 Gérard Lods Delphine Roubinet Jürg M Matter Richard Leprovost Philippe Gouze Oman Drilling Project Science Team others article yao2020high 2020 Journal of Mineralogical and Petrological Sciences 115 Japan Association of Mineralogical Sciences 247--260 3 Yuan Yao Eiichi Takazawa Sayantani Chatterjee Antonin Richard Christophe Morlot Laura Creon Salim Al--Busaidi Katsuyoshi Michibayashi Oman Drilling Project Science Team others article Cox2020 2020 10.1111/maps.13541 Meteoritics and Planetary Science 55 Space Science and Technology Centre (SSTC), School of Earth and Planetary Science, Curtin University, Perth, WA 6102, Australia; Lunar and Planetary Institute (LPI)—USRA, 3600 Bay Area Boulevard, Houston, TX 77058, United States; Jacobs-JETS, Astromaterials Research and Exploration Science Division, NASA Johnson Space Center, Houston, TX 77058, United States; United States; United Kingdom; France; Belgium; Australia; Austria; Germany; Japan; Mexico; Netherlands; China 8 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85088926758&doi=10.1111%2fmaps.13541&partnerID=40&md5=7587801cade0a9fed2b6e7658ce3fe1d cited By 12 M.A. Cox T.M. Erickson M. Schmieder R. Christoffersen D.K. Ross A.J. Cavosie P.A. Bland D.A. Kring S. Gulick J.V. Morgan G. Carter E. Chenot G. Christeson P. Claeys C. Cockell M.J.L. Coolen L. Ferrière C. Gebhardt K. Goto H. Jones J. Lofi C. Lowery R. Ocampo-Torres L. Pérez-Cruz A. Pickersgill M. Poelchau A. Rae C. Rasmussen M. Rebolledo-Vieyra U. Riller H. Sato J. Smit S. Tikoo N. Tomioka M. Whalen A. Wittmann J. Urrutia-Fucugauchi L. Xiao K.E. Yamaguchi IODP-ICDP Expedition 364 Scientists article Martin-Jones2020245 Reconstructions of the timing and frequency of past eruptions are important to assess the propensity for future volcanic activity, yet in volcanic areas such as the East African Rift only piecemeal eruption histories exist. Understanding the volcanic history of scoria-cone fields, where eruptions are often infrequent and deposits strongly weathered, is particularly challenging. Here we reconstruct a history of volcanism from scoria cones situated along the eastern shoulders of the Kenya–Tanzania Rift, using a sequence of tephra (volcanic ash) layers preserved in the ~250-ka sediment record of Lake Chala near Mount Kilimanjaro. Seven visible and two non-visible (crypto-) tephra layers in the Lake Chala sequence are attributed to activity from the Mt Kilimanjaro (northern Tanzania) and the Chyulu Hills (southern Kenya) volcanic fields, on the basis of their glass chemistry, textural characteristics and known eruption chronology. The Lake Chala record of eruptions from scoria cones in the Chyulu Hills volcanic field confirms geological and historical evidence of its recent activity, and provides first-order age estimates for seven previously unknown eruptions. Long and well-resolved sedimentary records such as that of Lake Chala have significant potential for resolving regional eruption chronologies spanning hundreds of thousands of years. © 2019 The Authors. Journal of Quaternary Science Published by John Wiley & Sons Ltd 2020 English 02678179 10.1002/jqs.3140 Journal of Quaternary Science 35 John Wiley and Sons Ltd 245-255 Department of Geography, University of Cambridge, Cambridge, United Kingdom; Limnology Unit, Department of Biology, Ghent University, Gent, Belgium; Renard Centre of Marine Geology, Department of Geology, Ghent University, Gent, Belgium; Lancaster Environment Centre, University of Lancaster, Lancaster, United Kingdom; Department of Geology, Trinity College Dublin, Dublin, Ireland 1-2 geochemistry; historical perspective; lacustrine deposit; tephra; tephrochronology; volcanic eruption; volcanic glass; volcanism, East African Rift; East African Rift; Kenya; Kenya Rift; Kilimanjaro [Tanzania]; Lake Challa; Tanzania https://www.scopus.com/inward/record.uri?eid=2-s2.0-85071268499&doi=10.1002%2fjqs.3140&partnerID=40&md5=9164e0fd515ee4cb72fa21608be7b271 cited By 6 C. Martin-Jones C. Lane M. Van Daele T.V.D. Meeren C. Wolff H. Moorhouse E. Tomlinson D. Verschuren article Zoccatelli2020 Article 2020 10.1016/j.jhydrol.2020.124879 Journal of Hydrology 587 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85083334024&doi=10.1016%2fj.jhydrol.2020.124879&partnerID=40&md5=ab0e3da756b02e67827cba2276f8eb6e Cited by: 12 D. Zoccatelli F. Marra J. Smith D. Goodrich C. Unkrich M. Rosensaft E. Morin article qu2020hydrothermal 2020 Precambrian Research 343 Elsevier 105705 Yuangao Qu Mark A Zuilen Aivo Lepland article Kılıç2020375 Given its intense seismic activity and damaging earthquake generation potential, the western part of the North Anatolian Fault constitutes a serious natural hazard. As a result, the fault is monitored with a broad range of seismological and geodetic instrumentation making it a natural laboratory environment for scientific studies. One of the long-term projects in this region is GONAF (Geophysical Borehole Observatory at the North Anatolian Fault) which is the first borehole seismometer network project in Turkey. GONAF is a joint research project that started in 2011 as joint initiative of the Turkish Ministry of Interior, Disaster and Emergency Management Presidency AFAD and GFZ and the German Research Center for Geoscience Helmholtz Center Potsdam. The aim of GONAF is to detect, examine, and monitor the microseismic activity in the region and to observe the physical processes before, during and after a large Marmara earthquake (M > 7.0) that is expected to rupture the western part of the North Anatolian Fault, below the Marmara Sea along the Princes Islands segment or even further to the west. For this purpose, the permanent GONAF observatory was established consisting of 7 borehole seismometer arrays installed down to a depth of 300 m. In this paper, we report on regional stress changes in the western part of the North Anatolian Fault Zone (NAFZ) using instrumental data and the Coulomb stress method. We also present preliminary results of the observation and evaluation of microseismic activity obtained from the GONAF observatory. For the automatic evaluation of real-time data, Seiscomp3, RTQUAKE, and Earthworm Softwares were used. Within the scope of automatic earthquake detection studies, between March, 2016 and November, 2017, a total of 2568 earthquakes were detected using the RTQUAKE software. Of these, 1459 could be analyzed. While the magnitude of the analyzed earthquakes varies between 0.8 and 4.2, the depth of these events ranges from 2 to 30 km. © 2020, Springer Nature B.V. Article 2020 English 13834649 10.1007/s10950-020-09907-6 Journal of Seismology 24 Springer 375 – 395 2 Sea of Marmara; Turkey; borehole geophysics; Coulomb criterion; earthquake damage; earthquake magnitude; geophysical method; seismograph; seismology https://www.scopus.com/inward/record.uri?eid=2-s2.0-85081586883&doi=10.1007%2fs10950-020-09907-6&partnerID=40&md5=deffd2d113aa03d9bb0505bbc7107a9d Cited by: 2 Tuğbay Kılıç Recai F. Kartal Filiz T. Kadirioğlu Marco Bohnhoff Murat Nurlu Diğdem Acarel Patricia Martínez Garzon Vedat Özsarac article Russell202053 The Neogene and Quaternary are characterized by enormous changes in global climate and environments, including global cooling and the establishment of northern high-latitude glaciers. These changes reshaped global ecosystems, including the emergence of tropical dry forests and savannahs that are found in Africa today, which in turn may have influenced the evolution of humans and their ancestors. However, despite decades of research we lack long, continuous, well-resolved records of tropical climate, ecosystem changes, and surface processes necessary to understand their interactions and influences on evolutionary processes. Lake Tanganyika, Africa, contains the most continuous, long continental climate record from the mid-Miocene (∼ 10 Ma) to the present anywhere in the tropics and has long been recognized as a top-priority site for scientific drilling. The lake is surrounded by the Miombo woodlands, part of the largest dry tropical biome on Earth. Lake Tanganyika also harbors incredibly diverse endemic biota and an entirely unexplored deep microbial biosphere, and it provides textbook examples of rift segmentation, fault behavior, and associated surface processes. To evaluate the interdisciplinary scientific opportunities that an ICDP drilling program at Lake Tanganyika could offer, more than 70 scientists representing 12 countries and a variety of scientific disciplines met in Dar es Salaam, Tanzania, in June 2019. The team developed key research objectives in basin evolution, source-to-sink sedimentology, organismal evolution, geomicrobiology, paleoclimatology, paleolimnology, terrestrial paleoecology, paleoanthropology, and geochronology to be addressed through scientific drilling on Lake Tanganyika. They also identified drilling targets and strategies, logistical challenges, and education and capacity building programs to be carried out through the project. Participants concluded that a drilling program at Lake Tanganyika would produce the first continuous Miocene-present record from the tropics, transforming our understanding of global environmental change, the environmental context of human origins in Africa, and providing a detailed window into the dynamics, tempo and mode of biological diversification and adaptive radiations. © Author(s) 2020. This work is distributed under the Creative Commons Attribution 4.0 License. 2020 English 18168957 10.5194/sd-27-53-2020 Scientific Drilling 27 Copernicus GmbH 53-60 Department of Earth, Environmental, and Planetary Sciences, Brown University, Providence, RI, United States; Lancaster Environment Centre, Lancaster University, Lancaster, United Kingdom; Department of Geosciences, University of Arizona, Tucson, AZ, United States; Department of Geosciences, Penn State University, University Park, PA, United States; Tanzania Fisheries Research Institute, TAFIRI-Kigoma Centre, Kigoma, Tanzania; Department of Geography, Cambridge University, Cambridge, United Kingdom; British Geological Survey, Nottingham, United Kingdom; Tanzania Petroleum Development Corporation, Dar es Salaam, Tanzania; Department of Earth and Environmental Sciences, University of Kentucky, Lexington, KY, United States; Continental Scientific Drilling Coordination Office, University of Minnesota, Minneapolis, MN, United States; Center of Integrative Geosciences, University of Connecticut, Storrs, CT, United States; Zoological Institute, Department of Environmental Sciences, University of Basel, Basel, Switzerland; Department of Earth Sciences, Syracuse University, Syracuse, NY, United States; Unit of Evolutionary Biology/Systematic Zoology, University of Potsdam, Potsdam, Germany; University of Giessen, Germany; Petroleum Upstream Regulatory Authority, Tanzania; Arizona State University, United States; University of New Mexico, United States; University of Burundi, Burundi; University of Kiel, Germany; Hamilton College, United States; University of Notre Dame, United States; University of Houston, United States; Queen's University, United Kingdom; University of Minnesota, Duluth, United States; University of Massachusetts, United States; Rice University, United States; Berkeley Geochronology Center, United States; Tulane University, United States; US Geological Survey, United States; University of Cologne, Germany; University of Brussels, Belgium; Justus Liebig University, Germany; University of Tübingen, Germany; Potsdam University, Germany; Geoforschungszentrum, Germany; Tanzania Fisheries Institute, Tanzania; University of Rhode Island, United States; Washington University, United States; SUERC, United Kingdom; University of Wisconsin, United States; Natural History Museum, United Kingdom; University of Dar es Salaam, Tanzania; Hydrobiology Laboratory, Uvira, Democratic Republic Congo; Tanzania Wildlife Research Institute, Tanzania; University of Bern, Switzerland; University of Louisiana, United States; Geological Survey of Finland, Finland; University of Wyoming, United States; Aberystwyth University, United Kingdom; Lamont Doherty Earth Observatory, United States; Nanjing Institute of Geography and Limnology, China; CNIEH, Spain; University of Oklahoma, United States; University of Texas, Austin, United States; Durham University, United Kingdom; Glasgow University, SUERC, United Kingdom; Indiana State University, United States; University of Lille, France; Max Planck Institute, Germany; Nanjing Inst. Limnology, China; Leibniz Institute of Applied Geophysics, Germany Biology; Climate change; Ecosystems; Forestry; Geochronology; Infill drilling; Tropics, Continental climate; Environmental contexts; Evolutionary process; Global environmental change; Research objectives; Scientific discipline; Scientific drilling; Tropical dry forest, Lakes https://www.scopus.com/inward/record.uri?eid=2-s2.0-85085683873&doi=10.5194%2fsd-27-53-2020&partnerID=40&md5=85eea71cb40261ba4beddd3d334ecfe7 cited By 6 J.M. Russell P. Barker A. Cohen S. Ivory I. Kimirei C. Lane M. Leng N. Maganza M. McGlue E. Msaky A. Noren L.P. Boush W. Salzburger C. Scholz R. Tiedemann S. Nuru C. Albrecht R. Ali R. Arrowsmith D. Asanga Y. Asmerom C. Bakundukize T. Bauersachs C. Beck M. Berke E. Beverley M. Blaauw L. Boush E. Brown C. Campisano B. Carrapa I. Castaûeda S. Dee A. Deino C. Ebinger G. Ellis V. Foerster K. Fontijn G. Gehrels A. Indemaur E. Jovanovska A. Junginger S. Kaboth J. Kallmeyer J. King B. Konecky D. Mark P. McIntyre E. Michel D. Mkuu L. Morgan C. Mtetela N. Muderwha J. Muirhead C. Mumbi M. Muschick D. Nahimana V. Ngowi P. Njiko S. Nkenyeli H. Nkotagu G. Ntakimazi D. Oppo L. Purkamo J. Rick H. Roberts F. Ronco J. Russell C. Sangweni Y. Shaghude J. Shigela D. Shillington C.S. Sophia M. Sier M. Soreghan T. Spanbauer C. Spencer-Jones R. Staff J. Stone J. Todd M. Trauth B. Bocxlaer F. Viehberg H. Vogel H. Vonhof C. Wolff Q. Wu C. Yost C. Zeeden article wiersberg_identification_2020 On-line monitoring of drilling mud gas was for the first time applied during continuous wireline coring of the COSC-1 borehole (Jämtland, central Sweden) to analyse formation gases and to identify inflow gas zones. Nearly complete gas records were obtained with 3 m depth resolution from 662 m (installation of the separator for gas extraction) to 1709 m and 6 m resolution from 1709 m to 2490 m depth (COSC-1 final depth: 2496 m) for H2, CH4, CO2, and He. Between 662 m and 1400 m, both He and CH4 form broad peaks superimposed by several spike-like features. Zones with gas spikes coincide with high resistivity intervals from dual laterolog (DLL) geophysical borehole logging and show fractures in borehole televiewer (BHTV) images, drill core scans, and visual core inspection. Therefore, we assume gas inflow through open fractures where DLLd/DLLs ratios {\textgreater}1.5 imply the presence of free gas. The correlation between helium and DLLd/DLLs ratios no longer appears at depths greater than {\textasciitilde}1550 m, probably because the formation gases are dissolved in formation fluids at higher pressure. Below 1550 m depth, the He concentration drops significantly, whereas the CH4 concentration remains relatively high and H2 and CO2 reach maximum values. The high amount of H2 and CH4 at depths below 1616 m, from where friction between the casing and the drill string was reported, imply that these gases are most certainly artificially generated at depths below 1616 m and at least partly of artificial origin at shallower depths. 2020 mar en 0883-2927 10.1016/j.apgeochem.2019.104513 Applied Geochemistry 114 104513 COSC, Downhole logging, Drilling mud gas analysis, Formation fluids, Natural fractures http://www.sciencedirect.com/science/article/pii/S0883292719303221 Simona Pierdominici Henning Lorenz Bjarne Almqvist Iwona Klonowska article Kleine2020 Article 2020 10.1016/j.epsl.2020.116210 Earth and Planetary Science Letters 538 Elsevier 116210 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85081658343&doi=10.1016%2fj.epsl.2020.116210&partnerID=40&md5=46b063151004d070023bf21c561a4d02 Cited by: 11; All Open Access, Green Open Access B.I. Kleine A. Stefánsson S.A. Halldórsson J.D. Barnes article Goswami2020 Knowledge of the in situ stress regime is critical to investigate the genesis of recurrent triggered seismicity over the past five decades in the Koyna seismogenic zone. Orientations of in situ horizontal stresses are determined for the first time from analyses of image logs in a 3 km deep scientific borehole KFD1 in the area. KFD1 passed through 1,247 m thick Deccan Traps and continued 1,767 m in the granitic basement. Stress-induced wellbore failures, breakouts and drilling-induced tensile fractures, are identified in the acoustic and microresistivity images of the granitic basement. Additionally, tightly constrained focal mechanisms of 50 earthquakes of M ≥ 3.6, reported in literature, are inverted to constrain the stress regime. Salient results are as follows: (i) wellbore breakouts and drilling-induced tensile fractures constrain N9°W ± 17° orientation for maximum horizontal principal stress (SHmax); (ii) consistency with the regional NNW-SSE orientation of SHmax from inversion of earthquake focal mechanisms shows that the borehole data are representative for the Koyna region; (iii) breakout rotations at multiple depths below 2,100 m indicate that the borehole may have passed through localized fault damage zones; (iv) consistent strike azimuths of steeply dipping fractures with SHmax orientation indicate favorable conditions for strike-slip to normal transitional faulting environment; and (v) stress inversion of 50 well-determined earthquake focal mechanisms supports transitional faulting environment in the Koyna seismogenic zone. Thus, stress orientation and fracture information from borehole data, together with stress regime constrained from inversion of earthquake focal mechanisms, shed new light on the faulting environment in the region. ©2020. American Geophysical Union. All Rights Reserved. 2020 English 02787407 10.1029/2019TC005647 Tectonics 39 Blackwell Publishing Ltd Ministry of Earth Sciences, Borehole Geophysics Research Laboratory, Karad, India; Now at CSIR-National Geophysical Research Institute, Hyderabad, India 1 Boreholes; Buildings; Earthquakes; Fracture; Horizontal wells; Infill drilling; Oil field equipment; Seismographs; Stresses; Strike-slip faults; Well logging, Borehole breakouts; Drilling-induced tensile fractures; Principal stress; Seismogenic zones; Stress orientations; Stress rotation, Fault slips, borehole breakout; borehole logging; Deccan Traps; drilling; faulting; focal mechanism; fracture; in situ stress; induced response; seismicity, India https://www.scopus.com/inward/record.uri?eid=2-s2.0-85078501819&doi=10.1029%2f2019TC005647&partnerID=40&md5=bdd15b250e33a85266e4b2ac083a83bd cited By 12 D. Goswami P. Hazarika S. Roy article Panagiotopoulos2020 Article 2020 10.1016/j.quascirev.2019.106044 Quaternary Science Reviews 227 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85075153203&doi=10.1016%2fj.quascirev.2019.106044&partnerID=40&md5=cc46a83b844d90418e7021868a342c6a Cited by: 26; All Open Access, Green Open Access, Hybrid Gold Open Access Konstantinos Panagiotopoulos Jens Holtvoeth Katerina Kouli Elena Marinova Alexander Francke Aleksandra Cvetkoska Elena Jovanovska Jack H. Lacey Emma T. Lyons Connie Buckel Adele Bertini Timme Donders Janna Just Niklas Leicher Melanie J. Leng Martin Melles Richard D. Pancost Laura Sadori Paul Tauber Hendrik Vogel Bernd Wagner Thomas Wilke article Das20201097 Koyna region in western India experienced more than 1,00,000 earthquakes of different magnitudes (M ~ 1.0–6.3) in the past five decades. Earthquakes in this region are believed to be triggered by a change in fluid pressure due to the percolation of the reservoir (Koyna and Warna reservoir) water into the subsurface. A drilling program was set up by the Ministry of Earth Sciences, India and International Continental Scientific Drilling Program (ICDP) to study the deep subsurface lithology, structure, thermal attributes, etc. as the area is covered by ~ 950 m of thick Deccan basalts. This paper reviews all the hypotheses proposed by earlier workers to explain the mechanism of reservoir trigger causing earthquakes and summarizes such theories to a simple generic model. Slip tendency analysis was further carried out based on the proposed model to explain the dependence of fault slip on fault geometry, rock mechanical properties, stress and fluid gradients. Finally, faults at various depths were characterized (favourably oriented, unfavourably oriented and severely misoriented) based on their potential to go into failure. © 2020, Institute of Geophysics, Polish Academy of Sciences & Polish Academy of Sciences. 2020 English 18956572 10.1007/s11600-020-00457-6 Acta Geophysica 68 Springer 1097-1112 Indian Institute of Science Education and Research, Bhopal, MP 462066, India 4 Earthquakes; Infill drilling; Lithology; Reservoirs (water); Solvents, Continental scientific drillings; Fault geometry; Fluid pressures; Generic modeling; Subsurface lithology; Tendency analysis, Fault slips, decadal variation; earthquake event; earthquake magnitude; fault geometry; fault slip; literature review; rock mechanics; seismicity, India; Koyna; Maharashtra https://www.scopus.com/inward/record.uri?eid=2-s2.0-85087569434&doi=10.1007%2fs11600-020-00457-6&partnerID=40&md5=e2825c942f3415db5794b51284d7cfa0 cited By 5 D. Das J. Mallik article Allstädt2020754 Remagnetization is an important issue in palaeomagnetism. Here, we discuss an extraordinarily thick (∼74 m) dual-polarity transition zone between the Gauss and Matuyama Chrons. The studied succession is from a drill core through lacustrine sediments of palaeo-Lake Idaho (Snake River Plain, NW United States of America) that are intercalated with basalt units. We identified detrital Ti-rich titanomagnetite and magnetite in lamellar exsolutions as the main carriers of a primary remanence, likely derived from the basalts that erupted in the Snake River Plain. Stepwise thermal demagnetization revealed a single-component remanent magnetization with reversed and normal polarities above and below the transition zone, respectively. Based on rock-magnetic results, microscopic observations, and previously known events in the evolution of palaeo-Lake Idaho, the reversed-polarity component in the transition zone represents a secondary chemical remanent magnetization caused by magnetic mineral alteration or partial neo-formation of magnetite, in association with strong depletion of the primary detrital magnetic minerals that affected a wide depth range below the level where the remagnetization event occurred. This remagnetization event was most likely related to lake-level lowering and partial desiccation of palaeo-Lake Idaho. Understanding the nature and origin of the remagnetization allows to identify the polarity boundary in the unusual case of a secondary magnetization with reversed polarity produced downward in a sequence to an extraordinary large depth. Based on available age information, the observed reversal represents the Gauss/Matuyama boundary, which provides an important age constraint for palaeoclimatic interpretation of the succession. © 2020 The Author(s) 2020. Published by Oxford University Press on behalf of The Royal Astronomical Society. 2020 English 0956540X 10.1093/gji/ggaa165 Geophysical Journal International 222 Oxford University Press 754-768 Paleoenvironmental Dynamics Group, Institute of Earth Sciences, Heidelberg University, Im Neuenheimer Feld 234-236, Heidelberg, 69120, Germany; Department of Geosciences, University of Tübingen, Hölderlinstr. 12, Tübingen, 72074, Germany; Institute of Geology and Mineralogy, University of Cologne, Zülpicherstr. 49a, Cologne, 50674, Germany 2 Basalt; Core drilling; Demagnetization; Gaussian distribution; Geomagnetism; Lakes; Lithology; Magnetite; Magnetization; Minerals, Chemical remanent magnetization; Lacustrine sediments; Microscopic observations; Remanent magnetization; Single components; Snake river plains; Stepwise thermal demagnetization; United States of America, Magnetic polarity, basalt; geomagnetism; lacustrine deposit; magnetic mineral; paleomagnetism; remagnetization; remanent magnetization; titanomagnetite, Idaho; Snake River Plain; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-85086761818&doi=10.1093%2fgji%2fggaa165&partnerID=40&md5=a425f2e0c2810c2ed506487e427792aa cited By 1 F.J. Allstädt E. Appel W. Rösler A.A. Prokopenko U. Neumann T. Wenzel J. Pross article Bali20201221 Article 2020 10.1130/G47791.1 Geology 48 1221 – 1225 12 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85096411629&doi=10.1130%2fG47791.1&partnerID=40&md5=78df0f56a2c9cea6277bbef45ec2a280 Cited by: 21; All Open Access, Bronze Open Access, Green Open Access Enikő Bali Guðmundur H. Guðfinnsson László E. Aradi Ábel Szabó Csaba Szabó Robert Zierenberg Larryn W. Diamond Thomas Pettke Guðmundur Ó Friðleifsson article Gehrels2020257 Uranium-lead (U-Pb) geochronology was conducted by laser ablation - inductively coupled plasma mass spectrometry (LA-ICPMS) on 7175 detrital zircon grains from 29 samples from the Coconino Sandstone, Moenkopi Formation, and Chinle Formation. These samples were recovered from ∼520 m of drill core that was acquired during the Colorado Plateau Coring Project (CPCP), located in Petrified Forest National Park (Arizona). A sample from the lower Permian Coconino Sandstone yields a broad distribution of Proterozoic and Paleozoic ages that are consistent with derivation from the Appalachian and Ouachita orogens, with little input from local basement or Ancestral Rocky Mountain sources. Four samples from the Holbrook Member of the Moenkopi Formation yield a different set of Precambrian and Paleozoic age groups, indicating derivation from the Ouachita orogen, the East Mexico arc, and the Permo-Triassic arc built along the Cordilleran margin. A total of 23 samples from the Chinle Formation contain variable proportions of Proterozoic and Paleozoic zircon grains but are dominated by Late Triassic grains. LA-ICPMS ages of these grains belong to five main groups that correspond to the Mesa Redondo Member, Blue Mesa Member and lower part of the Sonsela Member, upper part of the Sonsela Member, middle part of the Petrified Forest Member, and upper part of the Petrified Forest Member. The ages of pre-Triassic grains also correspond to these chronostratigraphic units and are interpreted to reflect varying contributions from the Appalachian orogen to the east, Ouachita orogen to the southeast, Precambrian basement exposed in the ancestral Mogollon Highlands to the south, East Mexico arc, and Permian-Triassic arc built along the southern Cordilleran margin. Triassic grains in each chronostratigraphic unit also have distinct U and thorium (Th) concentrations, which are interpreted to reflect temporal changes in the chemistry of arc magmatism. Comparison of our LA-ICPMS ages with available chemical abrasion thermal ionization mass spectrometry (CA-TIMS) ages and new magnetostratigraphic data provides new insights into the depositional history of the Chinle Formation, as well as methods utilized to determine depositional ages of fluvial strata. For parts of the Chinle Formation that are dominated by fine-grained clastic strata (e.g., mudstone and siltstone), such as the Blue Mesa Member and Petrified Forest Member, all three chronometers agree (to within ∼ 1 Myr), and robust depositional chronologies have been determined. In contrast, for stratigraphic intervals dominated by coarse-grained clastic strata (e.g., sandstone), such as most of the Sonsela Member, the three chronologic records disagree due to recycling of older zircon grains and variable dilution of syn-depositional-age grains. This results in LA-ICPMS ages that significantly predate deposition and CA-TIMS ages that range between the other two chronometers. These complications challenge attempts to establish a well-defined chronostratigraphic age model for the Chinle Formation. © 2020 George Gehrels et al. 2020 English 26283735 10.5194/gchron-2-257-2020 Geochronology 2 Copernicus GmbH 257-282 Department of Geosciences, University of Arizona, Tucson, AZ 85721, United States; Lamont-Doherty Earth Observatory of Columbia University, Palisades, NY 10964, United States; Earth and Planetary Sciences, Rutgers University, Piscataway, NJ 08854, United States; Petrified Forest National Park, Petrified ForestAZ 86028, United States; Berkeley Geochronology Center, 2455 Ridge Rd., Berkeley, CA 94709, United States; Natural History Museum of Utah, Department of Geology and Geophysics, University of Utah, Salt Lake City, UT 84108, United States; Department of Geosciences, University of Texas at Dallas, Richardson, TX 75080, United States 2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85123292135&doi=10.5194%2fgchron-2-257-2020&partnerID=40&md5=73e22e865c75da505d8dc62fc5eecd3d cited By 9 G. Gehrels D. Giesler P. Olsen D. Kent A. Marsh W. Parker C. Rasmussen R. Mundil R. Irmis J. Geissman C. Lepre article drake_geochronology_2020 The deep biosphere hosted in fractured rocks within the upper continental crust is one of the least understood and studied ecological realms on Earth. Scarce knowledge of ancient life and paleo-fluid flow within this realm is owing to the lack of deep drilling into the crust. Here we apply microscale high spatial-resolution analytical techniques to fine-grained secondary minerals in a deep borehole (COSC-1) drilled into the Silurian-Devonian Scandinavian Caledonide mountain range in central Sweden. The aim is to detect and date signs of ancient microbial activity and low-temperature fluid circulation in micro-karsts (foliation-parallel dissolution cavities in the rock) and fractures at depth in the nappe system. Vein carbonates sampled at 684 to 2210 m show a decreased C isotope variability at depths below 1050 m; likely due to decreased influence of organic-C at great depth. Micro-karsts at 122\–178 m depth feature at least two generations of secondary calcite and pyrite growth in the voids as shown by secondary ion mass spectrometry analytical transects within individual grains. The younger of these two precipitation phases shows 34S-depleted &delta;34Spyrite values (&minus;19.8 &plusmn; 1.6&permil; vs. Vienna-Canyon Diablo Troilite (V-CDT)) suggesting microbial sulfate reduction in situ. The calcite of this late phase can be distinguished from the older calcite by higher &delta;18Ocalcite values that correspond to precipitation from ambient meteoric water. The late stage calcite gave two separate laser ablation inductively coupled mass spectrometry-derived U-Pb ages (9.6 &plusmn; 1.3 Ma and 2.5 &plusmn; 0.2 Ma), marking a minimum age for widespread micro-karst formation within the nappe. Several stages of fluid flow and mineral precipitation followed karst formation; with related bacterial activity as late as the Neogene-Quaternary; in structures presently water conducting. The results show that our combined high spatial-resolution stable isotope and geochronology approach is suitable for characterizing paleo-fluid flow in micro-karst; in this case, of the crystalline crust comprising orogenic nappe units. 2020 feb en 10.3390/geosciences10020056 Geosciences 10 56 2 stable isotopes, Caledonides, deep drilling (COSC-1), in situ U-Pb geochronology, secondary minerals https://www.mdpi.com/2076-3263/10/2/56 Henrik Drake Nick M. W. Roberts Martin J. Whitehouse article Lozhkin2020168 Article 2020 10.1111/bor.12413 Boreas 49 168 – 180 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85073987705&doi=10.1111%2fbor.12413&partnerID=40&md5=13fb3f710ec2f53cd07714d2777b9820 Cited by: 4 Anatoly V. Lozhkin Patricia M. Anderson Pavel S. Minyuk Julia A. Korzun Ekaterina Y. Nedorubova Mariana A. Kirillova article Stelbrink20201156 Ancient Lake Ohrid is the oldest and biologically most diverse freshwater lake in Europe. The recent deep-drilling campaign SCOPSCO provided detailed insights into the lake's limnological history over the past 1.36 my. However, it remains unclear what factors triggered the onset of radiations and whether diversification rates remained constant throughout their evolution. We therefore inferred time-calibrated molecular phylogenies for eight invertebrate groups endemic to Lake Ohrid and performed diversification-rate analyses for the four most species-rich groups. The molecular-clock analyses indicate that few groups possibly originated in springs or rivers in the ‘proto-Balkans’ during the pre-lake phase. The onset of all other radiations, however, can be correlated to one of the three limnological phases in the Ohrid Graben and in Lake Ohrid since 1.9 mya. We therefore assume that the onset of radiations was triggered by an increased ecological opportunity arising from massive environmental changes in the course of the lake deepening. The diversification-rate analyses further indicate that the groups examined diversified with a constant rate. Although the reconstruction of the early evolutionary history of these groups remains challenging, our data suggest that the relatively stable conditions in Lake Ohrid together with its high buffer capacity likely prevented significant changes in diversification rates over time. © 2020 International Association for Great Lakes Research Article 2020 English 03801330 10.1016/j.jglr.2020.06.012 Journal of Great Lakes Research 46 International Association of Great Lakes Research 1156 – 1161 5 Balkans; Lake Ohrid; Invertebrata; Mya; Ecology; Ancient lakes; Buffer capacity; Deep drilling; Environmental change; Evolutionary history; Fresh water lakes; Molecular clock; Molecular phylogeny; adaptive radiation; evolution; invertebrate; lacustrine environment; phylogenetics; phylogeny; Lakes https://www.scopus.com/inward/record.uri?eid=2-s2.0-85087507121&doi=10.1016%2fj.jglr.2020.06.012&partnerID=40&md5=c360769036156750b469d534e045941f Cited by: 6 Björn Stelbrink Thomas Wilke Christian Albrecht article Xia2020 Natural gas hydrate is considered as one of the best potential alternative resource to address the world's energy demand. The available geological data at the Mallik site of Canada indicates the vertical heterogeneities of hydrate reservoir petrophysical properties. According to the logging data and sample analysis results at the Mallik 2L-38 well, a 2D model of geologically descriptive hydrate-bearing sediments was established to investigate the multiphase flow behaviors in hydrate reservoir induced by gas recovery and the effects of perforation interval on gas production performance. Firstly, the constructed model with vertical heterogeneous structures of permeability, porosity, and hydrate saturation was validated by matching the measured data in the Mallik 2007 test. The excessive residual methane in the hydrate reservoir observed in simulated results indicates insufficient gas production efficiency. For more effective methane recovery from a hydrate reservoir, the effect of perforation interval on long-term gas production performance was investigated based on the validated reservoir model. The simulation results suggest that both the location and length of the perforation interval have significant impact on hydrate dissociation behavior, while the gas production performance is mainly affected by the length of the perforation interval. To be specific, an excellent gas release performance is found in situations where the perforation interval is set at the interface between a hydrate reservoir and an underlying water-saturated zone. By increasing the perforation interval lengths of 5 m, 8 m, and 10 m, the gas release volumes from hydrate dissociation and gas production volumes from production wells are increased by 34%, 52%, and 57% and 37%, 58%, and 62%, respectively. © 2020 Yingli Xia et al. 2020 English 14688115 10.1155/2020/8833884 Geofluids 2020 Hindawi Limited Key Laboratory of Groundwater Resources and Environment, Ministry of Education, Jilin University, Changchun, 130021, China bearing capacity; gas hydrate; gas production; gas supply; hydrocarbon reservoir; natural gas; permeability; porosity; reservoir characterization; two-dimensional modeling, Canada https://www.scopus.com/inward/record.uri?eid=2-s2.0-85087566872&doi=10.1155%2f2020%2f8833884&partnerID=40&md5=67873319660d398b61a86e783c5e8562 cited By 6 Y. Xia T. Xu Y. Yuan X. Xin article Kletetschka2020 Chicxulub impact (66 Ma) event resulted in deposition of spheroids and melt glass, followed by deposition of diamectite and carbonate ejecta represented by large polished striated rounded pebbles and cobbles, henceforth, called Albion Formation1 Pook’s Pebbles, name given from the first site identified in central Belize, Cayo District. Here we report that magnetic analysis of the Pook’s Pebbles samples revealed unique electric discharge signatures. Sectioning of Pook’s Pebbles from the Chicxulub ejecta from the Albion Formation at Belize showed that different parts of Pook’s Pebbles had not only contrasting magnetization directions, but also sharply different level of magnetizations. Such behavior is indicative of electric discharge taking place sometimes during the formation of the Chicxulub ejecta blanket. In addition, some of the Pook’s Pebbles’ surface had recrystallized down to 0.2 mm depth. This is evidence of localized extreme pressures and temperatures during the fluidized ejecta formation which was imprinted in the outer layer of Pook’s Pebbles. Recrystallization caused formation of nanophase iron along the surface, which was revealed by mapping of both natural remanent magnetization and of saturation remanence magnetization signatures. While the spheroids’ magnetization orientation is consistent with reversed magnetic field at the time of impact, the study of the Pook’s Pebbles provided, in addition, new evidence of electric charging during the vapor plume cloud processes. © 2020, The Author(s). 2020 10.1038/s41598-020-65974-2 Scientific Reports 10 Institute of Geology, Czech Academy of Sciences, Rozvojová 269, Prague 6, 16500, Czech Republic; Department of Applied Geophysics, Charles University, Albertov 6, Prague 2, 12843, Czech Republic; Geophysical Institute, University of Alaska, Fairbanks, 903 N Koyukuk Drive, Fairbanks, AK, United States; NASA Headquarters, Washington, DC 20546, United States; Department of Infectious Diseases, Virology, University of Heidelberg, Heidelberg, Germany 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85086007779&doi=10.1038%2fs41598-020-65974-2&partnerID=40&md5=a2b93c9d8ea0960b526302690fbcf10b cited By 6 G. Kletetschka A. Ocampo Uria V. Zila T. Elbra article Nono2020 Article 2020 10.1016/j.jvolgeores.2018.04.021 Journal of Volcanology and Geothermal Research 391 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85047402066&doi=10.1016%2fj.jvolgeores.2018.04.021&partnerID=40&md5=003cfac308bec4cef179fc9815ac3d77 Cited by: 29; All Open Access, Bronze Open Access, Green Open Access Franck Nono Benoit Gibert Fleurice Parat Didier Loggia Sarah B. Cichy Marie Violay article Zhao2020128 The Late Paleozoic tectono–magmatic history and basement of the Maya block are poorly understood due to the lack of exposures of coeval magmatic rocks in the region. Recently, IODP–ICDP Expedition 364 recovered drill core samples at borehole M0077A from the peak ring of the Chicxulub impact crater, offshore of the Yucatán peninsula in the Gulf of México, have been studied comprehensively. In the lowermost ~600 m of the drill core, impact–deformed granitoids, and minor felsite and dolerite dykes are intercalated with impact melts and breccias. Zircon U-Pb dating of granitoids yielded ages of around 326 ± 5 Ma, representing the first recovery of Late Paleozoic magmatic rocks from the Maya block, which could be genetically related to the convergence of Laurentia and Gondwana. The granitoids show the features of high K2O/Na2O, LaN/YbN and Sr/Y ratios, but very low Yb and Y contents, indicating an adakitic affinity. They are also characterized by slightly positive ԑNd(326Ma) of 0.17–0.68, intermediate initial 87Sr/86Sr(326Ma) of 0.7036–0.7047 and two–stage Nd model age (TDM2) of 1027–1069 Ma, which may indicate a less evolved crustal source. Thus, the adakitic granitoids were probably generated by partial melting of thickened crust, with source components similar to Neoproterozoic metagabbro in the Carolina block (Pan–African Orogeny materials) along Peri–Gondwana. Felsite dykes are shoshonitic with typical continental arc features that are sourced from a metasomatic mantle wedge by slab–fluids. Dolerite dykes display OIB–type features such as positive Nb and Ta anomalies and low ThNpm/NbNpm. In our interpretation, the Chicxulub adakitic granitoids of this study are formed by crustal anatexis due to asthenospheric upwelling resulting from slab breakoff. Through comparing sources and processes of Late Paleozoic magmatism along the Peri–Gondwanan realm, a tearing slab breakoff model may explain the discontinuous magmatism that appears to have occurred during the convergence of Laurentia and Gondwana. © 2020 International Association for Gondwana Research 2020 10.1016/j.gr.2019.12.003 Gondwana Research 82 128-150 State Key Laboratory of Geological Processes and Mineral Resources, Planetary Science Institute, School of Earth Sciences, China University of Geosciences, Wuhan, China; State Key Laboratory of Space Science Institute, Lunar and Planetary Science, Macau university of Science and Technology, Taipa, Macau, China; Institute for Geophysics, Jackson School of Geosciences, University of Texas at AustinTX 78758-4445, United States; Department of Earth Science and Engineering, Imperial College London, London, SW7 2BP, United Kingdom; Lunar and Planetary Institute, 3600 Bay Area Boulevard, Houston, TX 77058, United States; Instituto de Geofisica, Universidad Nacional Autónoma de México, México D.F., Mexico; Analytical, Environmental and Geo–Chemistry, Vrije Universiteit Brussel, Pleinlaan 2, Elsene, 1050, Belgium; Eyring Materials Center for Solid State Science, Physical Sciences, Arizona State University, Tempe, AZ 85287–8301, United States; School of Geographical and Earth Sciences, University of Glasgow, Gregory, Lilybank Gardens, Glasgow, G12 8QQ, United Kingdom; University of Utah, Department of Geology and Geophysics, 115 S 1460 E (FASB), Salt Lake City, UT 84112, United States; Department of Palaeobiology, Swedish Museum of Natural History, Stockholm, Sweden; Natural History Museum, Burgring 7, Vienna, 1010, Austria; Department of Lithospheric Research, University of Vienna, Althanstrasse 14, Vienna, A–1090, Austria; Biogéosciences, UMR 6282, CNRS, University of Bourgogne Franche–Comté, 6 boulevard Gabriel, Dijon, F–21000, France; Instituto de Geofísica, Universidad Nacional Autónoma de México, Cd. Universitaria, Coyoacán Ciudad de México, C. P. 04510, Mexico; Japan Agency for Marine–Earth Science and Technology, 2–15, Natsushima–cho, Yokosuka–city, Kanagawa 237–0061, Japan; Department of Chemistry, Toho University, Funabashi, Chiba, 274–8510, Japan; NERC Argon Isotope Facility, Scottish Universities Environmental Research Centre (SUERC), Rankine Avenue, East Kilbride G75 0QF, United Kingdom https://www.scopus.com/inward/record.uri?eid=2-s2.0-85079391651&doi=10.1016%2fj.gr.2019.12.003&partnerID=40&md5=1316c93044e567c4e04b8e4e9f4363b7 cited By 23 J. Zhao L. Xiao S.P.S. Gulick J.V. Morgan D. Kring J.U. Fucugauchi M. Schmieder S.J. Graaff A. Wittmann C.H. Ross P. Claeys A. Pickersgill P. Kaskes S. Goderis C. Rasmussen V. Vajda L. Ferrière J.-G. Feignon E. Chenot L. Pérez-Cruz H. Sato K. Yamaguchi IODP-ICDP Expedition 364 Scientists article Kelemen2020 Article 2020 10.1016/j.chemgeo.2020.119628 Chemical Geology 550 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85086503881&doi=10.1016%2fj.chemgeo.2020.119628&partnerID=40&md5=57f2d759208cf4aa81e35d9301de74dc Cited by: 187; All Open Access, Hybrid Gold Open Access Peter B. Kelemen Noah McQueen Jennifer Wilcox Phil Renforth Greg Dipple Amelia Paukert Vankeuren article Navarro2020 A plume of vaporized sediments and basement rocks was ejected to the top of atmosphere when a 10–15 km asteroid impacted on Yucatan in the Southern Gulf of Mexico about 66 million years ago. The Chicxulub impact-vapor plume emitted a flash of light that had clues on the chemistry and degree of vaporization of the target surface material. Here we simulate the asteroid impact by vaporizing marine carbonate sediments cored in the Yaxcopoil-1 borehole in the Chicxulub crater using an intense infrared laser pulse. We investigate two sedimentary layers that represent the most dominant mineral phases of the target sequence: carbonates and sulfates. Their main constituents are 86% calcite and 74% anhydrite, respectively. The laser-induced vapor plumes were produced from each layer in a background simulated late Cretaceus atmosphere (0.16% CO2, 30% O2, and 69.84% N2). Time-resolved spectroscopic analyses from the laser-induced plumes were carried out using experimental and synthetic spectra. The vapor plumes had similar temperatures (≥7800 K) at 1 μs and their spectra showed similar emissions. The spectra contained the following lines in nm: Ca+ (mostly at 393.4 and 396.9 with less prominence at 370.6 and 373.7), Ca (422.7, 430.3, 443.6, 445.5, 527.0, 560.3, 616.4, and 657.3), N (746.8 and 821.6), O (777.7), and C (794.5). Molecular bands were not conspicuous which indicated complete vaporization of the target material by the laser pulse. The contribution of the granitic basement was examined using synthetic spectra. The expected emissions according to their intensities are: Na (589.6), Ca+ (393.4), Al (396.2, 309.3), Ca+ (396.9), Ca (422.7), Na (819.5) and K (766.5, 769.9). The results suggest that the emission corresponded to Ca+ and Ca originated mostly from the volatilization of the marine sediments, and Na, Al, and K from the basement rocks. The physico-chemical evolution of the Chicxulub impact-vapor plume could be deduced by deciphering the temperature and electron density from the emission lines of Ca and Ca+. These physical parameters can be used in gas dynamic models to predict the fluxes and nature of gases, vapors and mineral phases that were introduced into the atmosphere and better assess their impact to the environment and the biosphere. © 2020 Elsevier Inc. 2020 10.1016/j.icarus.2020.113813 Icarus 346 Posgrado en Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, Avenida Ciudad Universitaria 3000, Ciudad de México, Coyoacán C.P. 04510, Mexico; Programa Universitario de Perforaciones en Océanos y Continentes, Instituto de Geofísica, Universidad Nacional Autónoma de México, Ciudad Universitaria, Ciudad de México, Coyoacán C.P. 04510, Mexico; Laboratorio de Química de Plasmas y Estudios Planetarios, Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, Circuito Exterior, Ciudad Universitaria, Ciudad de México, Coyoacán C.P. 04510, Mexico; Laboratorio de Fotofísica y Películas Delgadas, Instituto de Ciencias Aplicadas y Tecnología, Universidad Nacional Autónoma de México, Ciudad Universitaria, Ciudad de México, Coyoacán C.P. 04510, Mexico; Laboratorio de Difracción de Rayos X and Laboratorio Nacional de Geoquímica y Mineralogía, Instituto de Geología, Universidad Nacional Autónoma de México, Ciudad Universitaria, Ciudad de México, Coyoacán C.P. 04510, Mexico https://www.scopus.com/inward/record.uri?eid=2-s2.0-85084039851&doi=10.1016%2fj.icarus.2020.113813&partnerID=40&md5=af6bc22e6b517b3cdb6b8d2bda783489 cited By 2 K.F. Navarro J. Urrutia-Fucugauchi M. Villagran-Muniz C. Sánchez-Aké T. Pi-Puig L. Pérez-Cruz R. Navarro-González article Lozhkin2020 Article 2020 10.1016/j.revpalbo.2020.104242 Review of Palaeobotany and Palynology 279 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85083894880&doi=10.1016%2fj.revpalbo.2020.104242&partnerID=40&md5=da592676564d8d62ad6fcc1e6cd0ed14 Cited by: 3 Anatoly V. Lozhkin Patricia M. Anderson article Veneranda2020349 In the present work, near-infrared, laser-induced breakdown spectroscopy, Raman, and X-ray diffractometer techniques have been complementarily used to carry out a comprehensive characterization of a terrestrial analogue selected from the Chesapeake Bay impact structure (CBIS). The obtained data clearly highlight the key role of Raman spectroscopy in the detection of minor and trace compounds, through which inferences about geological processes occurred in the CBIS can be extrapolated. Beside the use of commercial systems, further Raman analyses were performed by the Raman laser spectrometer (RLS) ExoMars Simulator. This instrument represents the most reliable tool to effectively predict the scientific capabilities of the ExoMars/Raman system that will be deployed on Mars in 2021. By emulating the analytical procedures and operational restrictions established by the ExoMars mission rover design, it was proved that the RLS ExoMars Simulator can detect the amorphization of quartz, which constitutes an analytical clue of the impact origin of craters. Beside amorphized minerals, the detection of barite and siderite, compounds crystallizing under hydrothermal conditions, helps indirectly to confirm the presence of water in impact targets. Furthermore, the RLS ExoMars Simulator capability of performing smart molecular mappings was successfully evaluated. © Copyright 2020, Mary Ann Liebert, Inc., publishers 2020. 2020 10.1089/ast.2019.2095 Astrobiology 20 349-363 CSIC-CAB Associated Unit Erica, Department of Condensed Matter Physics, University of Valladolid, Boecillo, Spain; Department of Analytical Chemistry, University of the Basque Country (UPV/EHU), Leioa, Spain; Institut d'Astrophysique Spatiale, CNRS/Université Paris-Sud, Orsay, France; Department of Geosciences, CEED/GEO, University of Oslo, Oslo, Norway 3 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85081146972&doi=10.1089%2fast.2019.2095&partnerID=40&md5=b49739d9a3dfb978a78b45348cbcff03 cited By 14 M. Veneranda G. Lopez-Reyes J.A. Manrique J. Medina P. Ruiz-Galende I. Torre-Fdez K. Castro C. Lantz F. Poulet H. Dypvik S.C. Werner F. Rull article 2020 10.1029/2020EO148771 Eos 101 https://eos.org/science-updates/exploring-by-boring-geothermal-wells-as-research-tools T. Jordan P. Fulton J. Tester H. Asanuma D. Bruhn article Osinski2020108 The impact of asteroids and comets with planetary surfaces is one of the most catastrophic, yet ubiquitous, geological processes in the solar system. The Chicxulub impact event, which has been linked to the Cretaceous-Paleogene (K-Pg) mass extinction marking the beginning of the Cenozoic Era, is arguably the most significant singular geological event in the past 100 million years of Earth's history. The Chicxulub impact occurred in a marine setting. How quickly the seawater re-entered the newly formed basin after the impact, and its effects of it on the cratering process, remain debated. Here, we show that the explosive interaction of seawater with impact melt led to molten fuel-coolant interaction (MFCI), analogous to what occurs during phreatomagmatic volcanic eruptions. This process fractured and dispersed the melt, which was subsequently deposited subaqueously to form a series of well-sorted deposits. These deposits bear little resemblance to the products of impacts in a continental setting and are not accounted for in current classification schemes for impactites. The similarities between these Chicxulub deposits and the Onaping Formation at the Sudbury impact structure, Canada, are striking, and suggest that MFCI and the production of volcaniclastic-like deposits is to be expected for large impacts in shallow marine settings. © 2019 Geological Society of America. 2020 10.1130/G46783.1 Geology 48 108-112 Department of Earth Sciences, University of Western Ontario, London, ON N6A 5B7, Canada; Institute for Earth and Space Exploration, University of Western Ontario, London, ON N6A 5B7, Canada; School of Physics and Astronomy, University of Edinburgh, Edinburgh, EH9 3FD, United Kingdom; Institute for Geophysics, Jackson School of Geosciences, University of Texas at Austin, Austin, Texas, 78758, United States; Department of Geology, Universität Freiburg, Freiburg, 79085, Germany; Department of Geological Sciences, Jackson School of Geosciences, University of Texas at Austin, Austin, TX 78758, United States; Departments of Earth, Atmospheric, and Planetary Sciences, and Physics and Aerospace Engineering, Purdue University, West Lafayette, IN 47907, United States; Institute of Geology, Universität Hamburg, Hamburg, 20146, Germany; Department of Geophysics, Stanford University, Stanford, CA 95305, United States; Eyring Materials Center, Arizona State University, Tempe, AZ 85287, United States 2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85079774039&doi=10.1130%2fG46783.1&partnerID=40&md5=a44ef4b2ecea1068d95428dd5ab30eb0 cited By 21 G.R. Osinski R.A.F. Grieve P.J.A. Hill S.L. Simpson C. Cockell G.L. Christeson M. Ebert S. Gulick H.J. Melosh U. Riller S.M. Tikoo A. Wittmann article Li2020 The fossil record of Turonian to Santonian charophytes is very poor worldwide, probably due to the limited non-marine records from this age, when there was a global high stand in the relative sea level and, thus, a reduction in non-marine habitats. After this gap, the charophyte floras changed to their modern physiognomy, with dominance of the Characeae. Charophytes from the Turonian to Santonian in the Songliao Basin help to fill this significant gap in the evolution of charophytes. The recorded flora is formed by one member of the Clavatoraceae, Atopochara trivolvis var. restricta, and a greater diversity of Characeae, including Nodosochara (Turbochara) heilongjiangensis comb. nov., Lamprothamnium ellipticum, Lychnothamnus barbosai and Lychnothamnus quantouensis comb. nov. These findings showed that the Characeae began to dominate charophyte floras during the global sea level high stand, up to 8 Ma earlier than previously reported. The occurrence of the genus Lychnothamnus in the Turonian in the Songliao Basin represents the oldest record in Eurasia of this still-living genus. The occurrence of A. trivolvis var. restricta in the Turonian to Santonian in China in comparison with its previous records in the Albian?–Cenomanian in Europe indicates that this variety survived as a relict in North China, while the more-derived variety Atopochara trivolvis var. multivolvis had evolved elsewhere. The charophyte flora thrived in large, shallow, permanent freshwater lakes and sometimes in palustrine settings of the Quantou, Qingshankou and Yaojia formations, which explains its higher biodiversity in contrast with the other records that belong mainly to brackish settings. © 2019 Elsevier B.V. 2020 English 00346667 10.1016/j.revpalbo.2019.104154 Review of Palaeobotany and Palynology 274 Elsevier B.V. State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, 39 East Beijing Road, Nanjing, 210008, China; Nanjing Institute of Geology and Palaeontology, Centre for Excellence in Life and Paleoenvironment, Chinese Academy of Sciences, 39 East Beijing Road, Nanjing, 210008, China; China University of Geosciences, Beijing, 100083, China; State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing, 100083, China; Universitat de Barcelona-UB, Departament de Dinàmica de la Terra i de l'Oceà, Institut de Recerca de la Biodiversitat-IRBio, Martí i Franquès s/n, Barcelona, Catalonia 08028, Spain biodiversity; biogeography; charophyte; dominance; flora; fossil record; lacustrine environment; paleoecology; Santonian; sea level; sedimentology; species diversity; species occurrence; taphonomy; Turonian, China; Europe; Songliao Basin, Characeae; Charales; Clavatoraceae; Lamprothamnium; Lychnothamnus https://www.scopus.com/inward/record.uri?eid=2-s2.0-85077302064&doi=10.1016%2fj.revpalbo.2019.104154&partnerID=40&md5=abcb1a97ea7013cbf33fe736e83a8bfb cited By 1 S. Li Q. Wang Y. Zhang X. Wan C. Martín-Closas article Metzger2020 Article 2020 10.1016/j.jhydrol.2020.125254 Journal of Hydrology 590 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85088019197&doi=10.1016%2fj.jhydrol.2020.125254&partnerID=40&md5=f26aaf56e09b5097c3bee3b47e933d8b Cited by: 33 Asher Metzger Francesco Marra James A. Smith Efrat Morin article yoshida2020fluid 2020 Journal of Geophysical Research: Solid Earth 125 Wiley Online Library e2020JB020268 11 Kazuki Yoshida Atsushi Okamoto Hiroyuki Shimizu Ryosuke Oyanagi Noriyoshi Tsuchiya Oman Drilling Project Phase 2 Science Party article Hirono2020 Article 2020 10.1038/s43247-020-0004-z Communications Earth and Environment 1 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85103360895&doi=10.1038%2fs43247-020-0004-z&partnerID=40&md5=6998fab0290f96ea78b48108f0aa5510 Cited by: 7; All Open Access, Gold Open Access Tetsuro Hirono Shunya Kaneki Tsuyoshi Ishikawa Jun Kameda Naoya Tonoike Akihiro Ito Yuji Miyazaki article 10.1130/G46783.1 {The impact of asteroids and comets with planetary surfaces is one of the most catastrophic, yet ubiquitous, geological processes in the solar system. The Chicxulub impact event, which has been linked to the Cretaceous-Paleogene (K-Pg) mass extinction marking the beginning of the Cenozoic Era, is arguably the most significant singular geological event in the past 100 million years of Earth’s history. The Chicxulub impact occurred in a marine setting. How quickly the seawater re-entered the newly formed basin after the impact, and its effects of it on the cratering process, remain debated. Here, we show that the explosive interaction of seawater with impact melt led to molten fuel–coolant interaction (MFCI), analogous to what occurs during phreatomagmatic volcanic eruptions. This process fractured and dispersed the melt, which was subsequently deposited subaqueously to form a series of well-sorted deposits. These deposits bear little resemblance to the products of impacts in a continental setting and are not accounted for in current classification schemes for impactites. The similarities between these Chicxulub deposits and the Onaping Formation at the Sudbury impact structure, Canada, are striking, and suggest that MFCI and the production of volcaniclastic-like deposits is to be expected for large impacts in shallow marine settings.} 2019 11 0091-7613 10.1130/G46783.1 Geology 48 108-112 2 https://doi.org/10.1130/G46783.1 Gordon R. Osinski Richard A.F. Grieve Patrick J.A. Hill Sarah L. Simpson Charles Cockell Gail L. Christeson Matthias Ebert Sean Gulick H. Jay Melosh Ulrich Riller Sonia M. Tikoo Axel Wittmann article Maierhofer20192510 The 3.6 Ma El'gygytgyn impact structure, located in northeast Chukotka in Arctic Russia, was largely formed in acidic volcanic rocks. The 18 km diameter circular depression is today filled with Lake El'gygytgyn (diameter of 12 km) that contains a continuous record of lacustrine sediments of the Arctic from the past 3.6 Myr. In 2009, El'gygytgyn became the focus of the International Continental Scientific Drilling Program (ICDP) in which a total of 642.4 m of drill core was recovered. Lithostratigraphically, the drill cores comprise lacustrine sediment sequences, impact breccias, and deformed target rocks. The impactite core was recovered from 316.08 to 517.30 meters below lake floor (mblf). Because of the rare, outstanding recovery, the transition zone, ranging from 311.47 to 317.38 m, between the postimpact lacustrine sediments and the impactite sequences, was studied petrographically and geochemically. The transition layer comprises a mixture of about 6 m of loose sedimentary and volcanic material containing isolated clasts of minerals and melt. Shock metamorphic effects, such as planar fractures (PFs) and planar deformation features (PDFs), were observed in a few quartz grains. The discoveries of silica diaplectic glass hosting coesite, kinked micas and amphibole, lechatelierite, numerous impact melt shards and clasts, and spherules are associated with the impact event. The occurrence of spherules, impact melt clasts, silica diaplectic glass, and lechatelierite, about 1 m below the onset of the transition, marks the beginning of the more coherent impact ejecta layer. The results of siderophile interelement ratios of the transition layer spherules give indications of the relative contribution of the meteoritical component. © 2019 The Authors. Meteoritics & Planetary Science published by Wiley Periodicals, Inc. on behalf of The Meteoritical Society (MET). 2019 English 10869379 10.1111/maps.13243 Meteoritics and Planetary Science 54 University of Arkansas 2510-2531 Department of Lithospheric Research, University of Vienna, Althanstrasse 14, Vienna, A-1090, Austria; Natural History Museum, Burgring 7, Vienna, A-1010, Austria; Department of Geosciences, University of Massachusetts, Amherst, MA 01003, United States 10 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85062345071&doi=10.1111%2fmaps.13243&partnerID=40&md5=1270385f2b721aa2d39c6456468ab7e7 cited By 1 K. Maierhofer C. Koeberl J. Brigham-Grette article Hu20191161 The Continental Scientific Drilling Project in the Songliao Basin was aimed at solving a series of scientific problems involved in Cretaceous paleoclimate and paleoenvironmental research, the development of deep exploration techniques, and the earth's deep resource survey. As the main borehole of the scientific drilling project of Songliao Basin, SK- 2 has collected continuous and in- situ geophysical log data. In this paper, geophysical log data were used to reveal the range of petrophysical parameters of rocks in Huoshiling Formation. Combined with laboratory core NMR test analysis, the authors studied the pore structure characteristics of different igneous reservoirs. The results show that the Huoshiling Formation mainly consists of andesite, tuff, complex conglomerate and tuff mudstone. The igneous facies are dominated by the explosive facies and the effusion facies. The andesite and complex conglomerate are characterized by high resistivity and low acoustic wave time difference. The characteristics of the tuff are low resistivity and high acoustic time difference, and the tuff mudstone has the lowest resistivity. The reservoir has the characteristics of low porosity and low permeability, but the tuff reservoir has developed small and medium pores and has relatively good physical properties, and hence it is a favorable reservoir. The research results provide strong support for further evaluation of deep oil and gas resources and stratigraphic structure in the Songliao Basin. © 2019 Editorial Board of Geology in China. All rights reserved. 2019 Chinese 10003657 10.12029/gc20190516 Geology in China 46 Science Press 1161-1173 Key Laboratory of Geo-Detection, China University of Geosciences (Beijing), Ministry of Education, Beijing, 100083, China; School of Geophysics and Information Technology, China University of Geosciences, Beijing, 100083, China; Institute of Exploration Techniques, China Geological Survey, Hebei, Langfang, 065300, China; Chinese Academy of Geological Sciences, Beijing, 100037, China; Tianjin Branch, CNPC Logging, Tianjin, 300280, China; Cores and Samples Center of Natural Resources, China Geological Survey, Yanjiao, Hebei, 065201, China 5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85107649383&doi=10.12029%2fgc20190516&partnerID=40&md5=207874787dd5a1caca221a58d5500da8 cited By 3 D. Hu C. Zou C. Peng W. Wang Q. Lü H. Hou Y. Zhu J. Zhang Y. Ding F. Lin L. Cui R. Dou C. Xu K. Zhuo J. Yang article Hu20191161 The Continental Scientific Drilling Project in the Songliao Basin was aimed at solving a series of scientific problems involved in Cretaceous paleoclimate and paleoenvironmental research, the development of deep exploration techniques, and the earth's deep resource survey. As the main borehole of the scientific drilling project of Songliao Basin, SK- 2 has collected continuous and in- situ geophysical log data. In this paper, geophysical log data were used to reveal the range of petrophysical parameters of rocks in Huoshiling Formation. Combined with laboratory core NMR test analysis, the authors studied the pore structure characteristics of different igneous reservoirs. The results show that the Huoshiling Formation mainly consists of andesite, tuff, complex conglomerate and tuff mudstone. The igneous facies are dominated by the explosive facies and the effusion facies. The andesite and complex conglomerate are characterized by high resistivity and low acoustic wave time difference. The characteristics of the tuff are low resistivity and high acoustic time difference, and the tuff mudstone has the lowest resistivity. The reservoir has the characteristics of low porosity and low permeability, but the tuff reservoir has developed small and medium pores and has relatively good physical properties, and hence it is a favorable reservoir. The research results provide strong support for further evaluation of deep oil and gas resources and stratigraphic structure in the Songliao Basin. © 2019 Editorial Board of Geology in China. All rights reserved. Article 2019 Chinese 10003657 10.12029/gc20190516 Geology in China 46 Science Press 1161 – 1173 5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85107649383&doi=10.12029%2fgc20190516&partnerID=40&md5=207874787dd5a1caca221a58d5500da8 Cited by: 3 Dingyu Hu Changchun Zou Cheng Peng Wenshi Wang Qingtian Lü Hesheng Hou Yongyi Zhu Jinchang Zhang Hengchun Zhang Yujiao Ding Feng Lin Liwei Cui Rusheng Dou Changmin Xu Kun Zhuo Jinlei Yang article 2019 10.1029/2019EO125255 Eos 100 J. Eichelberger article Sinopoli201953 Our study aims to reconstruct climate changes that occurred at Lake Ohrid (south-western Balkan Peninsula), the oldest extant lake in Europe, between 160 and 70&thinsp;ka (covering part of marine isotope stage 6, MIS 6; all of MIS 5; and the beginning of MIS 4). A multi-method approach, including the "Modern Analog Technique" and the "Weighted Averaging Partial Least-Squares Regression", is applied to the high-resolution pollen sequence of the DEEP site, collected from the central part of Lake Ohrid, to provide quantitative estimates of climate and bioclimate parameters. This allows us to document climatic change during the key periods of MIS 6 and MIS 5 in southern Europe, a region where accurate climate reconstructions are still lacking for this time interval.</p> Our results for the penultimate glacial show cold and dry conditions, while the onset of the "last interglacial" is characterized by wet and warm conditions, with temperatures higher than today (by ca. 2&thinsp;<span classCombining double low line"inline-formula">ĝ</span>C). The Eemian also shows the well-known climatic tri-partition in the Balkans, with an initial pre-temperate phase of abrupt warming (128-121&thinsp;ka), a central temperate phase with decreasing temperatures associated with wet conditions (121-118&thinsp;ka), followed by a post-temperate phase of progressive change towards cold and dry conditions (118-112&thinsp;ka).</p> After the Eemian, an alternation of four warm/wet periods with cold/dry ones, likely related to the succession of Greenland stadials and cold events known from the North Atlantic, occurred. The observed pattern is also consistent with hydrological and isotopic data from the central Mediterranean.</p> The Lake Ohrid climate reconstruction shows greater similarity with climate patterns inferred from northern European pollen records than with southern European ones, which is probably due to its intermediate position and the mountainous setting. However, this hypothesis needs further testing as very few climate reconstructions are available for southern Europe for this key time period.</p>. © Author(s) 2019. 2019 English 18149324 10.5194/cp-15-53-2019 Climate of the Past 15 Copernicus GmbH 53-71 Dipartimento di Biologia Ambientale, Sapienza University of Rome, Rome, Italy; Dipartimento di Scienze della Terra, Sapienza University of Rome, Rome, Italy; Institut des Sciences de l'Evolution de Montpellier, University of Montpellier, CNRS, IRD, EPHE, Montpellier, France; Organic Geochemistry Unit, School of Chemistry, University of Bristol, Bristol, United Kingdom; Institute of Geology and Mineralogy, University of Cologne, Cologne, Germany; Wollongong Isotope Geochronology Laboratory, School of Earth and Environmental Sciences, University of Wollongong, Wollongong, Australia 1 climate variation; Eemian; marine isotope stage; paleoclimate; pollen; precipitation (climatology); temperature, Atlantic Ocean; Atlantic Ocean (North); Balkans; Lake Ohrid; Southern Europe https://www.scopus.com/inward/record.uri?eid=2-s2.0-85059940971&doi=10.5194%2fcp-15-53-2019&partnerID=40&md5=d73e79bb1ecaf7123dfdf12c08dac059 cited By 12 G. Sinopoli O. Peyron A. Masi J. Holtvoeth A. Francke B. Wagner L. Sadori article jia2019practice 2019 Drilling & Production Technology 42 31-34 1 Yan Jia Wang Wenshi Zhang Hengchun Xu Jie Cao Longlong article just2019rimo 2019 10.1594/PANGAEA.908116 PANGAEA PANGAEA https://doi.org/10.1594/PANGAEA.908116 Janna Just Leonardo Sagnotti Norbert R Nowaczyk Alexander Francke Bernd Wagner article Qin2024168 Article 2019 10.3969/J.ISSN.1006-768X.2019.01.10 Drilling & Production Technology 42 31-34+3 01 J. Yan W. Wang H. Zhang J. Xu L. Cao article Gao201973 2019 English 20959273 10.1016/j.scib.2018.12.017 Science Bulletin 64 Elsevier B.V. 73-75 State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences (Beijing), Beijing, 100083, China; School of Earth Sciences and Resources, China University of Geosciences (Beijing), Beijing, 100083, China; College of Earth Sciences, Jilin University, Changchun, 130026, China; Key Laboratory for Evolution of Past Life and Environment in Northeast Asia, Jilin University, Changchun, 130026, China; Research Center of Palaeontology and Stratigraphy, Jilin University, Changchun, 130026, China; School of Geophysics and Information Technology, China University of Geosciences (Beijing), Beijing, 100083, China 2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85059665857&doi=10.1016%2fj.scib.2018.12.017&partnerID=40&md5=42b843a817874c2e942be305b53361ab cited By 21 Y. Gao C. Wang P. Wang Y. Huang C. Zou article RN257 Journal Article 2019 Communications of the Geological Survey of Namibia 21 1-14 https://www.mme.gov.na/files/publications/78e_GSN%20Comms%2021_1_Rose%20et%20al%20GRIND-ECT.pdf C. V. Rose A.R. Prave K. D. Bergmann D. J. Condon S. A. Kasemann F. A. MacDonald K.-H. Hoffmann R. I. F. Trindade M. Zhu article Drabon20191 Article 2019 10.1016/j.precamres.2019.02.010 Precambrian Research 325 1 – 19 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85061905713&doi=10.1016%2fj.precamres.2019.02.010&partnerID=40&md5=ff0b77de89dcf3c980ce2340d18e6de3 Cited by: 30 Nadja Drabon Aleksandra Galić Paul R.D. Mason Donald R. Lowe article Guo20191137 When the seismic wave propagates in the underground media, the seismic wave energy will show a certain degree of attenuation. The quality factor Q is an important parameter for measuring the absorption and attenuation properties of the underground rock, and is of great significance for describing the lithological characteristics and predicting the oil and gas distribution. In this paper, the Q value analysis technique based on S transformation ratio method for deep seismic reflection data was developed, and the more accurate Q value was obtained. Taking the Shahezi Formation in the Songliao Basin as the main target layer, the authors calculated the Q value of the post-stack deep seismic reflection profile across Well SK-2, and then generated the Q value profile to summarize Q value distribution characteristics of the Shahezi Formation. The Q value distribution characteristics, combined with the logging, stratification and gas anomaly data of Well SK-2, suggest that the Shahezi Formation is a gas reservoir, and this discovery provides a way for the next deep reservoir prediction. This conclusion provides an idea for the further deep reservoir prediction and can serve the deep geological survey project in Northeast China. © 2019 Editorial Board of Geology in China. All rights reserved. Article 2019 Chinese 10003657 10.12029/gc20190514 Geology in China 46 Science Press 1137 – 1145 5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85107629646&doi=10.12029%2fgc20190514&partnerID=40&md5=91a6957c6b377f54f8eddccdba29259a Cited by: 1 Rui Guo Hesheng Hou Wei Fu Jin Yang Xuan Feng Zhanwu Lu Huailai Zhou article Caballero201962 Diatom-based transfer functions for salinity, precipitation and temperature were developed using a training set that included data from 40 sites along central Mexico. These transfer functions showed good performance parameters and were subsequently applied to the previously published diatom record from lake Chalco, southern Basin of Mexico. Heinrich stadials (HS-3 to HS-0) were reconstructed as cold and dry events, with HS-2 representing the coldest and driest conditions, while HS-1 shows a complex bimodal cooling pattern. Orbital scale variability is also recorded. High and variable lake salinities from ∼34 to 29 ka BP (marine isotope stage 3, MIS-3) corresponded with times of maximum summer insolation and evidences of frequent fires. MIS-2 was identified as a cold period, with low lake salinity associated with low evaporation, with two cold intervals during the minima in spring (∼25.5 ka BP) and summer (∼20 ka BP) insolation. The ∼20 ka BP cold event together with HS-2 (24-23 ka BP), defined a bimodal maximum cooling during the last glacial maximum (LGM: 24.5–19.5 ka BP) within the range of pollen-based estimates, further supporting a maximum tropical cooling of 4–5 °C for the LGM. The deglacial (19.5–11.5 ka BP) showed the highest precipitation anomalies with three peaks that closely correlated with glacier advances in the nearby mountains (Iztaccihuatl). The early Holocene marked a change towards high lake salinities and the highest positive temperature anomalies (+3.5 °C) during a peak in summer insolation. Even though at orbital scale Chalco showed a nearly opposite trend to the record from the more southerly lake Peten-Itza (Guatemala), at millennial scale it showed a common pattern of cold and dry conditions during HSs, comparable to other tropical latitude sites in the northern hemisphere and further supporting the idea that there is a strong coupling between tropical and higher latitudes climates, in particular with the North Atlantic. © 2018 Elsevier Ltd 2019 English 02773791 10.1016/j.quascirev.2018.12.002 Quaternary Science Reviews 205 Elsevier Ltd 62-75 Laboratorio de Paleolimnología, Instituto de Geofísica, Universidad Nacional Autónoma de México, Ciudad Universitaria, Coyoacán, Ciudad de México, CP 04510, Mexico; Instituto de Geología, Universidad Nacional Autónoma de México, Ciudad Universitaria, Coyoacán, Ciudad de México, CP 04510, Mexico Glacial geology; Incident solar radiation; Lakes; Paleolimnology; Tropics, Diatoms; Late Pleistocene; Micropaleontology; Monsoon; North America; Paleoclimatology, Transfer functions, climate variation; diatom; micropaleontology; monsoon; paleoclimate; paleolimnology; paleotemperature; Pleistocene; precipitation (climatology); quantitative analysis; salinity; transfer function, Atlantic Ocean; Atlantic Ocean (North); Guatemala [Central America]; Lake Peten Itza; Mexico [North America]; Peten; Valley of Mexico, Bacillariophyta https://www.scopus.com/inward/record.uri?eid=2-s2.0-85058506660&doi=10.1016%2fj.quascirev.2018.12.002&partnerID=40&md5=7503376714a91f5bb647f868343a1383 cited By 28 M. Caballero S. Lozano-García B. Ortega-Guerrero A. Correa-Metrio article BernhartOwen201997 Article 2019 10.1016/j.palaeo.2019.01.017 Palaeogeography, Palaeoclimatology, Palaeoecology 518 97 – 118 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85060103673&doi=10.1016%2fj.palaeo.2019.01.017&partnerID=40&md5=cfa6ed9e16d277f880783e4f069a02eb Cited by: 42 R. Bernhart Owen Robin W. Renaut Veronica M. Muiruri Nathan M. Rabideaux Tim K. Lowenstein Emma P. McNulty Kennie Leet Daniel Deocampo Shangde Luo Alan L. Deino Andrew Cohen Mark J. Sier Christopher Campisano Chuan-Chou Shen Anne Billingsley Anthony Mbuthia Mona Stockhecke article Urrutia-Fucugauchi201968 The IODP-ICDP Expedition 364 drilled into the Chicxulub crater, peering inside its well-preserved peak ring. The borehole penetrated a sequence of post-impact carbonates and a unit of suevites and clast-poor impact melt rock at the top of the peak ring. Beneath this sequence, basement rocks cut by pre-impact and impact dykes, with breccias and melt, were encountered at shallow depths. The basement rocks are fractured, shocked and uplifted, consistent with dynamic collapse, uplift and long-distance transport of weakened material during collapse of the transient cavity and final crater formation. © 2019 John Wiley & Sons Ltd, The Geologists' Association & The Geological Society of London 2019 10.1111/gto.12261 Geology Today 35 68-72 Universidad Nacional Autonoma de Mexico, Mexico; Coordinacion Plataformas Oceanograficas, UNAM, Mexico; Imperial College London, United Kingdom; University of Texas at Austin, United States; Arizona State University, United States; Montpellier University, France; United Kingdom; United States; France; Belgium; Australia; Japan; Germany; Mexico; Netherlands; China 2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85063648912&doi=10.1111%2fgto.12261&partnerID=40&md5=e60e9c51355824d5270d5baf7899c04c cited By 0 J. Urrutia-Fucugauchi L. Pérez-Cruz J. Morgan S. Gulick A. Wittmann J. Lofi J.V. Morgan S.P.S. Gulick E. Chenot G. Christeson P. Claeys C. Cockell M.J.L. Coolen L. Ferrière C. Gebhardt K. Goto H. Jones D.A. Kring C. Lowery C. Mellett R. Ocampo-Torres A. Pickersgill M. Poelchau A. Rae C. Rasmussen M. Rebolledo-Vieyra U. Riller H. Sato J. Smit S. Tikoo-Schantz N. Tomioka M. Whalen L. Xiao K.E. Yamaguchi T. Bralower G.S. Collins IODP-ICDP Expedition 364 Science Party article Lowery2019120 Extraterrestrial impacts that reshape the surfaces of rocky bodies are ubiquitous in the solar system. On early Earth, impact structures may have nurtured the evolution of life. More recently, a large meteorite impact off the Yucatán Peninsula in Mexico at the end of the Cretaceous caused the disappearance of 75% of species known from the fossil record, including non-avian dinosaurs, and cleared the way for the dominance of mammals and the eventual evolution of humans. Understanding the fundamental processes associated with impact events is critical to understanding the history of life on Earth, and the potential for life in our solar system and beyond. Scientific ocean drilling has generated a large amount of unique data on impact processes. In particular, the Yucatán Chicxulub impact is the single largest and most significant impact event that can be studied by sampling in modern ocean basins, and marine sediment cores have been instrumental in quantifying its environmental, climatological, and biological effects. Drilling in the Chicxulub crater has significantly advanced our understanding of fundamental impact processes, notably the formation of peak rings in large impact craters, but these data have also raised new questions to be addressed with future drilling. Within the Chicxulub crater, the nature and thickness of the melt sheet in the central basin is unknown, and an expanded Paleocene hemipelagic section would provide insights to both the recovery of life and the climatic changes that followed the impact. Globally, new cores collected from today’s central Pacific could directly sample the downrange ejecta of this northeast-southwest trending impact. Extraterrestrial impacts have been controversially suggested as primary drivers for many important paleoclimatic and environmental events throughout Earth history. However, marine sediment archives collected via scientific ocean drilling and geochemical proxies (e.g., osmium isotopes) provide a long-term archive of major impact events in recent Earth history and show that, other than the end-Cretaceous, impacts do not appear to drive significant environmental changes. © 2019 The Oceanography Society, Inc. 2019 10.5670/oceanog.2019.133 Oceanography 32 120-134 University of Texas Institute for Geophysics, Jackson School of Geosciences, Austin, TX, United States; Department of Earth Science and Engineering, Imperial College, London, United Kingdom; Department of Geosciences, Pennsylvania State University, University Park, PA, United States; University of Texas Institute for Geophysics, Jackson School of Geosciences, Austin, TX, United States 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85065918866&doi=10.5670%2foceanog.2019.133&partnerID=40&md5=f6cdf244574bb6d3971efec054ec6f2c cited By 4 C.M. Lowery J.V. Morgan S.P.S. Gulick T.J. Bralower G.L. Christeson E. Chenot P. Claeys C. Cockell M.J.L. Coolen L. Ferrière C. Gebhardt K. Goto S. Green H. Jones D.A. Kring J. Lofi C. Mellett R. Ocampo-Torres L. Pérez-Cruz A. Pickersgill M. Poelchau A. Rae C. Rasmussen M. Rebolledo-Vieyra U. Riller H. Sato J. Smit S. Tikoo N. Tomioka J. Urrutia-Fucugauchi M. Whalen A. Wittmann L. Xiao K. Yamaguchi Expedition 364 Scientists article Kaźmierczak2019 Article 2019 10.1016/j.precamres.2019.105357 Precambrian Research 331 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85066813779&doi=10.1016%2fj.precamres.2019.105357&partnerID=40&md5=c1bc726537ec15772c50c826be113740 Cited by: 3 Józef Kaźmierczak Barbara Kremer article Berndt201969 The northeast Atlantic encompasses archetypal examples of volcanic rifted margins. Twenty-five years after the last ODP (Ocean Drilling Program) leg on these volcanic margins, the reasons for excess melting are still disputed with at least three competing hypotheses being discussed. We are proposing a new drilling campaign that will constrain the timing, rates of volcanism, and vertical movements of rifted margins. This will allow us to parameterise geodynamic models that can distinguish between the hypotheses. Furthermore, the drilling-derived data will help us to understand the role of breakup magmatism as a potential driver for the Palaeocene-Eocene thermal maximum (PETM) and its influence on the oceanographic circulation in the earliest phase of the northeast Atlantic Ocean formation. Tackling these questions with a new drilling campaign in the northeast Atlantic region will advance our understanding of the long-term interactions between tectonics, volcanism, oceanography, and climate and the functioning of subpolar northern ecosystems and climate during intervals of extreme warmth. © Author(s) 2019. 2019 English 18168957 10.5194/sd-26-69-2019 Scientific Drilling 26 Copernicus GmbH 69-85 GEOMAR, Kiel, 24218, Germany; Centre for Earth Evolution and Dynamics, Department of Geosciences, University of Oslo, Oslo, 0315, Norway; VBPR, Oslo, 0349, Norway; School of Ocean and Earth Sciences, University of Southampton, Southampton, SO14 3ZH, United Kingdom; Department of Earth Science, University of Bergen, Bergen, 5007, Norway; Department of Earth Sciences, Utrecht University, Utrecht, 3584, Netherlands; DougalEARTH Ltd, Solihull, B91 3NU, United Kingdom; Department of Geoscience, University of Aarhus, Aarhus, 8000, Denmark; Department of Geological Sciences, Stockholm University, Stockholm, 106 91, Sweden; Geological Survey of Norway, Trondheim, 7040, Norway Geodynamics; Infill drilling; Volcanoes, Geodynamic models; Long-term interaction; North East Atlantic; Northeast Atlantic Ocean; Ocean drilling programs; Oceanographic circulation; Paleogene climate; Vertical movement, Climate change https://www.scopus.com/inward/record.uri?eid=2-s2.0-85076097338&doi=10.5194%2fsd-26-69-2019&partnerID=40&md5=f55f1ce6b7f0291a9f9da7370c01634e cited By 3 C. Berndt S. Planke D. Teagle R. Huismans T. Torsvik J. Frieling M.T. Jones D.A. Jerram C. Tegner J. Inge Faleide H. Coxall W.-L. Hong article Just201912445 Article 2019 10.1029/2019JB018297 Journal of Geophysical Research: Solid Earth 124 12445 – 12464 12 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85075158049&doi=10.1029%2f2019JB018297&partnerID=40&md5=e76e3efea70357c966b04a80c3d95f63 Cited by: 17; All Open Access, Green Open Access, Hybrid Gold Open Access J. Just L. Sagnotti N.R. Nowaczyk A. Francke B. Wagner article Hasberg2019675 Lake Towuti on Sulawesi Island, Indonesia, is located within the heart of the Indo-Pacific Warm Pool. This tropical lake is surrounded by ultramafic (ophiolitic) rocks and lateritic soils that create a unique ferruginous depositional setting. In order to understand modern sediment deposition in Lake Towuti, a set of 84 lake surface sediment samples was collected from across the entirety of the lake and samples were analyzed for their physical, chemical, mineralogical and biological constituents. End-member analyses were carried out to elucidate modern sediment origin, transport and depositional processes. This study found that allochthonous sediment, characterized by the concentrations of the elements Mg, Fe, Si and Al, as well as the clay and serpentine minerals, is dominated by fluvial supply from five distinct source areas. Granulometric data and the occurrence of organic matter of a terrestrial origin suggest that, in the southern and north-eastern parts of the lake the near-shore sediments may additionally be influenced by mass wasting. This is due at least partly to the particularly steep slopes in these areas. Furthermore, sediment composition suggests that sediment transport into deeper parts of the lake, particularly in the northern basin, is partly controlled by gravitational and density-driven processes such as turbidity currents. Directional sediment transport by persistent lake currents, in contrast, appears to be less important. Organic matter deposition in the ultra-oligotrophic lake, albeit limited, is dominated by autochthonous production, but with some contribution of fluvial and gravitational supply. Biogenic silica deposition, primarily from diatom frustules and sponge spicules, is very limited and is concentrated in only a few areas close to the shoreline that are characterized by shallow waters, but away from the areas of high suspension loads at the mouths of the major inlets. The results of this study build upon current and published work on short piston cores from Lake Towuti. Conversely, the results will support the interpretation of the depositional history and past climatic and environmental conditions derived from the composition of much longer records, which were obtained by the Towuti Drilling Project in May 2015 and are currently under investigation. © 2018 The Authors. Sedimentology © 2018 International Association of Sedimentologists Article 2019 English 00370746 10.1111/sed.12503 Sedimentology 66 Blackwell Publishing Ltd 675 – 698 2 Greater Sunda Islands; Lake Towuti; Malili Lakes; South Sulawesi; Sulawesi; Sunda Isles; Bacillariophyta; Biogeochemistry; Biological materials; Chemical analysis; Gravitation; Ocean currents; Organic compounds; Sediment transport; Sedimentation; Serpentine; Silica; Silicate minerals; Surficial sediments; Suspensions (fluids); Depositional process; Environmental conditions; Pacific warm pool; Provenance analysis; Redox condition; Sediment composition; Sedimentation process; Tropical lakes; depositional environment; lacustrine deposit; provenance; redox conditions; sediment transport; sedimentation; shallow water; Lakes https://www.scopus.com/inward/record.uri?eid=2-s2.0-85052403974&doi=10.1111%2fsed.12503&partnerID=40&md5=f4a62f810d995f41dfae24a779bc0f74 Cited by: 18; All Open Access, Green Open Access Ascelina K. M. Hasberg Satria Bijaksana Peter Held Janna Just Marina A. Morlock Stephan Opitz James M. Russell article Levy2019 During the late Quaternary several hypersaline lakes occupied the tectonic depression of the Dead Sea Basin, depositing sequences of primary-evaporitic mineral phases: aragonite (CaCO3), gypsum (CaSO4·2H2O) and halite (NaCl). Aragonite and gypsum were the dominant primary mineral phases during the glacial periods and their formation required significant import of bicarbonate (HCO3 −) and sulfate (SO4 2−) ions to the lake. While bicarbonate was likely derived from dissolution of calcite in the watershed, the sources of sulfate remained elusive. Here we investigate and quantify the long-term sulfate reservoir changes in the deep waters (hypolimnion) of Lake Lisan (the last glacial Dead Sea) using concentrations and stable isotopes of sulfur in pore-fluids from the cores that were drilled at the lake floor (2010–11) by ICDP (International Continental Drilling Program). From ca. 117ka, pore-fluid sulfate concentrations increased and the brine attained supersaturation with respect to gypsum, peaking during the last glacial maximum (LGM; ca. 20ka). Stable isotopes of pore-fluid sulfate (δ34S and δ18O) are similar to the values found in bulk sulfate minerals from the nearby Mount Sedom salt diapir. We suggest that relatively diluted and cool paleo-epilimnion water facilitated dissolution of halite and anhydrite (CaSO4) of the Mt. Sedom salt diapir, resulting in a localized increase in solution density. Subsequently, this solution sank and mixed with saline hypolimnion water, simultaneously replenishing chloride, sodium and sulfate reservoirs, while diluting it with respect to other solutes. The mixing of the calcium-rich gypsum saturated hypolimnion and the sulfate-rich sinking brine from above resulted in gypsum supersaturation. © 2019 Elsevier Ltd 2019 English 02773791 10.1016/j.quascirev.2019.105871 Quaternary Science Reviews 221 Elsevier Ltd Department of Geological & Environmental Sciences, Ben-Gurion University of the Negev, Beer Sheva, 8410501, Israel; Geological Survey of Israel, 32 Yesha'ayahu Leibowitz St., Jerusalem, 9692100, Israel; Institute of Earth Sciences, The Hebrew University of Jerusalem, Givat Ram, Jerusalem, 91904, Israel; Department of Hydrology and Microbiology, Zuckerberg Center, Ben-Gurion University of the Negev, Sede Boker, Israel Calcite; Calcium carbonate; Carbonate minerals; Chloride minerals; Dissolution; Drilling fluids; Glacial geology; Gypsum; Infill drilling; Isotopes; Lakes; Reservoirs (water); Saline water; Salt tectonics; Sodium chloride; Supersaturation, Dead sea; Hypersaline lakes; Last glacial; Last Glacial Maximum; Mt. Sedom diapir; Pore fluids; Solution density; Sulfate concentrations, Sulfur compounds, diapir; gypsum; isotopic analysis; Last Glacial; porewater; sulfate; supersaturation, Dead Sea; Israel; Mount Sedom; Southern District https://www.scopus.com/inward/record.uri?eid=2-s2.0-85071047767&doi=10.1016%2fj.quascirev.2019.105871&partnerID=40&md5=48e19754d5df6325369f2e568933d882 cited By 10 E.J. Levy O. Sivan G. Antler B. Lazar M. Stein Y. Yechieli I. Gavrieli article Yu2019160 The Nenjiang Formation in the Songliao Basin, northeastern China, is of great significance because it records a series of geological, geodynamical and paleoenvironmental events, such as lake transgression events, lake anoxic events, sea water incursion events, Cretaceous Normal Superchron, and important stratigraphic boundaries. Here we report a chronology for the non-marine Upper Cretaceous Nenjiang Formation based on secondary ion mass spectrometry (SIMS) U–Pb zircon analyses from the east borehole of the Cretaceous Continental Scientific Drilling and two outcrop sections, which are located in different structural provinces of the Songliao Basin. Stratigraphic correlation between the borehole sequence and the exposed outcrop sections is achieved by combining lithostratigraphy, biostratigraphy, and SIMS U–Pb zircon geochronology. Two bentonite layers are recognized in the Nenjiang Formation: the older occurs at the formational contact between the Yaojia and Nenjiang Formations; the younger occurs between Members 1 and 2 of the Nenjiang Formation. SIMS U–Pb zircon dating yields ages of 85.1–85.2 Ma and 83.0–83.3 Ma, respectively, representing ages of the boundaries of the Yaojia/Nenjiang Formations and Members 1/2 of the Nenjiang Formation, as well as ages of lake transgression events and associated lake anoxic events, and two of the sea water incursion events. Furthermore, the age of Cretaceous Normal Superchron termination can be estimated at 82.5–82.8 Ma. © 2019 Elsevier Ltd 2019 English 01956671 10.1016/j.cretres.2019.05.006 Cretaceous Research 102 Academic Press 160-169 State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, 100029, China; College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China; Institutions of Earth Science, Chinese Academy of Sciences, Beijing, 100029, China; China University of Geosciences, Beijing, 100083, China Cretaceous; geochronology; mass spectrometry; paleoenvironment; uranium-lead dating; zircon, China; Songliao Basin https://www.scopus.com/inward/record.uri?eid=2-s2.0-85068502817&doi=10.1016%2fj.cretres.2019.05.006&partnerID=40&md5=e84c180e76d64de26009ba062518ba80 cited By 17 Z. Yu H. He C. Deng D. Xi Z. Qin X. Wan C. Wang R. Zhu article Timms2019 Accessory mineral geochronometers such as apatite, baddeleyite, monazite, xenotime and zircon are increasingly being recognized for their ability to preserve diagnostic microstructural evidence of hypervelocity-impact processes. To date, little is known about the response of titanite to shock metamorphism, even though it is a widespread accessory phase and a U–Pb geochronometer. Here we report two new mechanical twin modes in titanite within shocked granitoid from the Chicxulub impact structure, Mexico. Titanite grains in the newly acquired core from the International Ocean Discovery Program Hole M0077A preserve multiple sets of polysynthetic twins, most commonly with composition planes (K1) = ~ { 1 ¯ 11 } , and shear direction (η1) = &lt; 110 &gt; , and less commonly with the mode K1 = {130}, η1 = ~ &lt;522 &gt;. In some grains, {130} deformation bands have formed concurrently with the deformation twins, indicating dislocation slip with Burgers vector b = &lt; 341 &gt; can be active during impact metamorphism. Titanite twins in the modes described here have not been reported from endogenically deformed rocks; we, therefore, propose this newly identified twin form as a result of shock deformation. Formation conditions of the twins have not been experimentally calibrated, and are here empirically constrained by the presence of planar deformation features in quartz (12 ± 5 and ~ 17 ± 5 GPa) and the absence of shock twins in zircon (&lt; 20 GPa). While the lower threshold of titanite twin formation remains poorly constrained, identification of these twins highlight the utility of titanite as a shock indicator over the pressure range between 12 and 17 GPa. Given the challenges to find diagnostic indicators of shock metamorphism to identify both ancient and recent impact evidence on Earth, microstructural analysis of titanite is here demonstrated to provide a new tool for recognizing impact deformation in rocks where other impact evidence may be erased, altered, or did not manifest due to generally low (&lt; 20 GPa) shock pressure. © 2019, Springer-Verlag GmbH Germany, part of Springer Nature. 2019 10.1007/s00410-019-1565-7 Contributions to Mineralogy and Petrology 174 The Institute for Geoscience Research (TIGeR), Space Science and Technology Centre, School of Earth and Planetary Sciences, Curtin University, GPO Box U1987, Perth, WA 6845, Australia; CSIRO Mineral Resources, Australian Resources Research Centre, 26 Dick Perry Avenue, Kensington, WA 6151, Australia; Jacobs-JETS, NASA Johnson Space Center, Astromaterials Research and Exploration Science Division, Mailcode XI3, 2101 NASA Parkway, Houston, TX 77058, United States; Department of Earth Science and Engineering, Imperial College London, London, United Kingdom; Institut für Geo- und Umweltnaturwissenschaften, Albert-Ludwigs-Universität, Freiburg, Albertstraße 23b, Freiburg, 79104, Germany; Department of Earth and Ocean Sciences, University of Liverpool, Liverpool, L69 3GP, United Kingdom; Eyring Materials Center, Arizona State University, Tempe, AZ, United States; Natural History Museum, Burgring 7, Vienna, 1010, Austria; Kochi Institute for Core Sample Research, Japan Agency for Marine-Earth Science and Technology, Kochi, Japan; Institute for Geophysics and Department of Geological Sciences, Jackson School of Geosciences, University of Texas at Austin, Austin, TX, United States 5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85065307578&doi=10.1007%2fs00410-019-1565-7&partnerID=40&md5=509f1d3079d4816026936f190bd7f097 cited By 18 N.E. Timms M.A. Pearce T.M. Erickson A.J. Cavosie A.S.P. Rae J. Wheeler A. Wittmann L. Ferrière M.H. Poelchau N. Tomioka G.S. Collins S.P.S. Gulick C. Rasmussen J.V. Morgan E. Chenot G.L. Christeson P. Claeys C.S. Cockell M.J.L. Coolen C. Gebhardt K. Goto S. Green H. Jones D.A. Kring J. Lofi C.M. Lowery R. Ocampo-Torres L. Pérez-Cruz A.E. Pickersgill M. Rebolledo-Vieyra U. Riller H. Sato J. Smit S.M. Tikoo J. Urrutia-Fucugauchi M.T. Whalen L. Xiao K.E. Yamaguchi IODP-ICDP Expedition 364 Scientists article Kämpf2019 This study presents the results of gas flux measurements of cold, mantle-derived CO2 release at the Bublák mofette field (BMF), located inside of the N-S directed Počátky Plesná fault zone (PPFZ). The PPFZ is presently seismically active, located in the eastern part of the Cheb Basin, western Eger Rift, Central Europe. The goal of the work was to identify the linkage between tectonics and gas flux. The investigated area has a size of 0,43 km2 in which 1.115 locations have been measured. Besides classical soil CO2 gas flux measurements using the closed chamber method (West Systems), drone-based orthophotos were used in combination with knowledge of plant zonation to find zones of high degassing in the agriculturally unused part of the BMF. The highest observed soil CO2 gas flux is 177.926,17 g m-2 d-1, and the lowest is 0,28 g m-2 d-1. Three statistical methods were used for the calculation of the gas flux: arithmetic mean, kriging, and trans-Gaussian kriging. The average CO2 soil degassing of the BMF is 30 t d-1 for an area of 0,43 km2. Since the CO2 soil degassing of the Hartoušov mofette field (HMF) amounts to 23 t d-1 for an area of 0,35 km2, the average dry degassing values of the BMF and HMF are in the same magnitude of order. The amount of CO2 flux from wet mofettes is 3 t d-1 for the BMF and 0,6 t d-1 for the HMF. It was found that the degassing in the BMF and HMF is not in accordance with the pull-apart basin interpretation, based on the direction of degassing as well as topography and sediment fill of the suggested basins. En-echelon faults inside of the PPFZ act as fluid channels to depth (CO2 conduits). These structures inside the PPFZ show beginning faulting and act as tectonic control of CO2 degassing. © 2019 Horst Kämpf et al. Article 2019 English 14688115 10.1155/2019/4852706 Geofluids 2019 Hindawi Limited Cheb Basin; Czech Republic; Karlovarsky; carbon dioxide; carbon emission; degassing; flux measurement; rift zone; tectonics https://www.scopus.com/inward/record.uri?eid=2-s2.0-85075134293&doi=10.1155%2f2019%2f4852706&partnerID=40&md5=6494ee1b0111bb038a75e5c75126780e Cited by: 6; All Open Access, Gold Open Access, Green Open Access Horst Kämpf Alena Sophie Broge Pouria Marzban Masoud Allahbakhshi Tobias Nickschick article Jankowski2019106 The irregular distribution of sand injections, traditionally termed “dykes" in the Polish geological literature, within individual Carpathian units and within individual lithofacies were observed during long-lasting field works. Injectites have been observed in the Magura Beds and in the Inoceramian Beds of the Polish and Romanian Carpathians, and in the Central Carpathian Paleogene deposits. However, they are most common in the Oligocene-Miocene Menilite Beds, where they are typical and abundant, particularly in the Skole Unit. Two clastic injectite types were distinguished: sedimentary (S-type) and tectonized (T-type). Based on the occurrence and interpretation of these injectites a new two-stage conceptual model is proposed for the Polish segment of the progressive Oligocene-Miocene Carpathian orogenic belt evolution. Type S clastic injectites are interpreted as having formed in the compressional stage, during foredeep basin migration while depositional slope changes were taking place in the Late Oligocene to Early Miocene. Type T injectites are interpreted as having formed by reactivation of S-type injectites in the last, mainly strike-slip, phases of Carpathian orogenic belt formation. © 2019, Polish Geological Institute. All rights reserved. 2019 10.7306/gq.1460 Geological Quarterly 63 106-125 Polish Geological Institute – National Research Institute, Rakowiecka 4, Warszawa, 00-975, Poland; University of Warsaw, Faculty of Geology, Żwirki i Wigury 93, Warszawa, 02-089, Poland 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85067936758&doi=10.7306%2fgq.1460&partnerID=40&md5=b1842bfd87f1b8794231a912bc7bf029 cited By 8 L. Jankowski A. Wysocka article Zeng2019126 2019 English 10009515 10.1111/1755-6724.14220 Acta Geologica Sinica (English Edition) 93 John Wiley and Sons Inc 126-130 Zhejiang Normal University, Jinhua, Zhejiang 321004; Institute of Earth and Environment, Chinese Academy of Sciences, Xi'an, Shaanxi 710061 S2 Cenozoic; clay mineral; detritus; lacustrine deposit; paleoclimate; paleoenvironment; sediment chemistry, China; Qinghai; Qinghai Lake https://www.scopus.com/inward/record.uri?eid=2-s2.0-85066462334&doi=10.1111%2f1755-6724.14220&partnerID=40&md5=42cb693a98bc1664b0536b820b62e4c0 cited By 0 M. Zeng Y. Song Y. Sheng article Qin2024168 Article 2019 10.19800/j.cnki.aps.2019.02.009 Acta Palaeontologica Sinica 58 232-248 2 Y. Wu J. Li H. Zhu article weisenberger2019operational 2019 https://doi.org/10.2312/ICDP.5059.001 GFZ German Research Centre for Geosciences Tobias Björn Weisenberger Magnús Tumi Gudmundsson Marie Dolores Jackson Carolyn F Gorny Andreas Türke Barbara Irene Kleine Beau Marshall Steffen Leth Jørgensen Viggó Thór Marteinsson Andri Stefánsson others article Zhang2019119 The second continental scientific drilling (SKII east) borehole in the Songliao Basin has been planned to be the deepest borehole to drill through the Cretaceous continental strata under the framework of the International Continental Scientific Drilling Program (ICDP) up to date. This borehole was designed not only to explore the potential relationships between dinosaur extinction and climate environment during the Cretaceous but also to achieve new breakthroughs in oil and gas exploration. The high hydrocarbon (oil and gas) potential of a source rock is highly dependent on its organic content. We used geophysical log data of Borehole SKII east to evaluate the organic content of organic-rich source rock. In the period of the first member in the Qingshankou Formation (K2qn1) from the study area, high accommodation space and anoxic environment could promote organic matter deposition. Firstly, based on geological information and abundant geophysical log data, the basic geophysical characteristics (including petrophysical, lithological, mineralogical, and sedimentary properties) of the Qingshankou Formation in Borehole SKII east were studied. Secondly, geophysical log response characteristics (including resistivity, porosity, radioactivity, mineral and element) of organic-rich source rocks were analyzed. Thirdly, we tried to obtain suitable methods to predict total organic carbon (TOC) content of the target formation with geophysical log data. The laboratorymeasured TOC values of core samples from Borehole SKI south were used to make calibrations with calculated TOC values from geophysical logs. Results from improved ΔlogR technique and Dual_Vsh method are consistent, and indicate that these two methods are effective in this formation. The calculated TOC values from these two methods are relatively desirable, and show that the organic-rich source rocks with high TOC content occurred in the K2qn1 (1646.00~1669.00 m). The highest TOC content can reach 9.15%. The bed thicknesses of organic-rich source rocks are totally up to 7.88 m. These organic-rich source rocks can be considered as excellent. This study demonstrated that improve ΔlogR technique can be applied to evaluate source rocks in the formations without maturity data, and the new method Dual_Vsh is also valid in the Qingshankou Formation. The organic-rich source rock evaluation results could promote further exploration and development of oil and gas resources in the upper Cretaceous formations, Songliao Basin. © 2019, The Association of Korean Geoscience Societies and Springer-Verlag GmbH Germany, part of Springer Nature. 2019 English 12264806 10.1007/s12303-018-0013-4 Geosciences Journal 23 Korean Association of Geoscience Societies 119-135 School of Geophysics and Information Technology, China University of Geosciences (Beijing), No. 29 Xueyuan Road, Haidian District, Beijing, 100083, China; Institute of Geophysics and Geomatics, China University of Geosciences, Wuhan, 430074, China; Development and research center, China Geological Survey, Beijing, 100037, China 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85046042430&doi=10.1007%2fs12303-018-0013-4&partnerID=40&md5=84267cdd0c2788f69ef62f1ea57abd4b cited By 4 X. Zhang C. Zou J. Zhao N. Li S. Zhang K.S. Kouamelan L. Xiao H. Ma Y. Niu article Armon201958 Article 2019 10.1016/j.quascirev.2019.06.005 Quaternary Science Reviews 216 58 – 73 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85067013433&doi=10.1016%2fj.quascirev.2019.06.005&partnerID=40&md5=b7e9bada52b2f49f1fd76b15d7256264 Cited by: 35 Moshe Armon Efrat Morin Yehouda Enzel inproceedings jesus2019oxide 2019 Geophysical Research Abstracts 21 Ana P Jesus Juergen Koepke João Mata others article Guillemot2019 Article 2019 10.1016/j.quascirev.2019.105997 Quaternary Science Reviews 225 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85073726369&doi=10.1016%2fj.quascirev.2019.105997&partnerID=40&md5=40dacbae3718a82687a32fbe7cd8a9c5 Cited by: 8 T. Guillemot M. Stockhecke A. Bechtel S.N. Ladd D.B. Nelson C.J. Schubert article Tillberg2019 Impact-generated hydrothermal systems have been suggested as favourable environments for deep microbial ecosystems on Earth, and possibly beyond. Fossil evidence from a handful of impact craters worldwide have been used to support this notion. However, as always with mineralized remains of microorganisms in crystalline rock, certain time constraints with respect to the ecosystems and their subsequent fossilization are difficult to obtain. Here we re-evaluate previously described fungal fossils from the Lockne crater (458 Ma), Sweden. Based on in-situ Rb/Sr dating of secondary calcite-albite-feldspar (356.6 ± 6.7 Ma) we conclude that the fungal colonization took place at least 100 Myr after the impact event, thus long after the impact-induced hydrothermal activity ceased. We also present microscale stable isotope data of13C-enriched calcite suggesting the presence of methanogens contemporary with the fungi. Thus, the Lockne fungi fossils are not, as previously thought, related to the impact event, but nevertheless have colonized fractures that may have been formed or were reactivated by the impact. Instead, the Lockne fossils show similar features as recent findings of ancient microbial remains elsewhere in the fractured Swedish Precambrian basement and may thus represent a more general feature in this scarcely explored habitat than previously known. © 2019 by the authors. Licensee MDPI, Basel, Switzerland. 2019 10.3390/geosciences9050202 Geosciences (Switzerland) 9 Department of Biology and Environmental Science, Linnaeus University, Kalmar, 392 31, Sweden; Department of Earth Sciences, University of Gothenburg, Box 460, Göteborg, 40530, Sweden; Department of Biology, University of Southern Denmark, Campusvej 55, Odense, 5230, Denmark; Department of Paleobiology, Swedish Museum of Natural History, Box 50 007, Stockholm, 104 05, Sweden; Department of Geosciences, Swedish Museum of Natural History, Box 50 007, Stockholm, 104 05, Sweden 5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85067627284&doi=10.3390%2fgeosciences9050202&partnerID=40&md5=057fef97b6a1e9d6544c97d47265fbac cited By 6 M. Tillberg M. Ivarsson H. Drake M.J. Whitehouse E. Kooijman M. Schmitt inproceedings teagle2019tethyan 2019 Geophysical Research Abstracts 21 Damon Teagle Matthew Cooper Michelle Harris Laura Crispini Peter Kelemen others article Thomas2019479 Article 2019 10.1130/G45801.1 Geology 47 479 – 482 5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85065547896&doi=10.1130%2fG45801.1&partnerID=40&md5=f9010bbada7dc99ae599fe98ef89fb9c Cited by: 12; All Open Access, Bronze Open Access, Green Open Access Camille Thomas Vincent Grossi Ingrid Antheaume Daniel Ariztegui article Rasmussen2019356 The zircon U-Pb system is one of the most robust geochronometers, but during an impact event individual crystals can be affected differently by the passage of the shock wave and impact generated heat. Unraveling the potentially complex thermal history recorded by zircon crystals that experienced variable levels of shock and heating, as well as additioanl pre- and post-impact thermal events, has been difficult using classical geochronological methods. The existing high-precision 40Ar/39Ar age constraints for the K-Pg Chicxulub event, and the previous U-Pb dating of the basement rocks from the impact site, make Chicxulub an ideal location to study impact-induced effects on the zircon U-Pb systematics and to evaluate potential 'memory effects' of pre-impact U-Pb signatures preserved within those individual zircon crystals. Recent IODP-ICDP drilling of the Chicxulub impact structure recovered 580 m of uplifted shocked granitoid and 130 m of melt and suevite, providing an unprecedented opportunity to study zircon crystals subjected to a range of shock pressures, thermal, and deformational histories. Zircon morphologies were classified using scanning electron microscopy (SEM) imaging and then samples were depth profiled using laser ablation inductively coupled plasma mass-spectrometry (LA-ICP-MS) to document the range of preserved age domains from rim-to-center within individual crystals. The results show U-Pb ages range from 66 to 472 Ma, which are consistent with both inherited Carboniferous and Late Paleozoic basement ages as well as Pb loss ages in response to the K-Pg impact event. While the bulk of the zircon grains preserve Paleozoic ages, high U (metamict) zones within fractured zircon crystals exhibited an age within uncertainty (66 ± 6.2 Ma) of the impact age (66.038 ± 0.049 Ma), indicating that inherited intragrain U-Pb kinetics and/or hydrothermal fluid flow may have controlled age resetting those zircon crystals rather than impact-induced shock and heating alone. Moreover, the calculated α-decay doses suggest that the zircon crystals experienced Stage 1 or early Stage 2 radiation damage accumulation. Therefore, we suggest that the lowered crystal annealing temperature in crystals that previoulsy experienced radiation damage make the zircon U-Pb clock either more susceptible to the relatively short heat pulse of the impact event, the moderate pressure and temperature conditions in the peak ring, and/or to hot-fluid flow in the long-lasting post impact hydrothermal system. © 2019 Elsevier B.V. 2019 10.1016/j.chemgeo.2019.07.029 Chemical Geology 525 356-367 Institute for Geophysics and Department of Geological Sciences, Jackson School of Geosciences, University of Texas at Austin, Austin, TX, United States; School of Geographical and Earth Sciences, University of Glasgow, Glasgow, United Kingdom; Argon Isotope Facility, Scottish Universities Environmental Research Centre (SUERC), East Kilbride, United Kingdom; Center for Lunar Science and Exploration, Universities Space Research Association Lunar and Planetary Institute, Houston, TX, United States; Eyring Materials Center, Arizona State University, Tempe, AZ, United States; Department of Earth Science and Engineering, Imperial College LondonSW7 2AZ, United Kingdom https://www.scopus.com/inward/record.uri?eid=2-s2.0-85070198430&doi=10.1016%2fj.chemgeo.2019.07.029&partnerID=40&md5=2441976b9bacd28edadd72562b906e11 cited By 13 C. Rasmussen D.F. Stockli C.H. Ross A. Pickersgill S.P. Gulick M. Schmieder G.L. Christeson A. Wittmann D.A. Kring J.V. Morgan IODP-ICDP Expedition 364 Science Party book Snedden20191 The Gulf of Mexico Basin is one of the most prolific hydrocarbon-producing basins in the world, with an estimated endowment of 200 billion barrels of oil equivalent. This book provides a comprehensive overview of the basin, spanning the US, Mexico and Cuba. Topics covered include conventional and unconventional reservoirs, source rocks and associated tectonics, basin evolution from the Mesozoic to Cenozoic Era, and different regions of the basin from mature onshore fields to deep-water subsalt plays. Cores, well logs and seismic lines are all discussed providing local, regional and basin-scale insights. The scientific implications of seminal events in the basin’s history are also covered, including sedimentary effects of the Chicxulub Impact. Containing over 200 color illustrations and 50 stratigraphic cross-sections and paleogeographic maps, this is an invaluable resource for petroleum industry professionals, as well as graduate students and researchers interested in basin analysis, sedimentology, stratigraphy, tectonics and petroleum geology. © John W. Snedden and William E. Galloway 2019. 2019 10.1017/9781108292795 The Gulf of Mexico Sedimentary Basin: Depositional Evolution and Petroleum Applications 1-326 Institute for Geophysics, University of Texas at Austin, United States; Department of Geological Sciences, Institute for Geophysics, University of Texas at Austin, United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-85092173394&doi=10.1017%2f9781108292795&partnerID=40&md5=fd9886c8a177e2594b03e346830f9739 cited By 47 J.W. Snedden W.E. Galloway article Koutsodendris2019 Characterised by a maximum expansion of continental ice sheets in the Northern Hemisphere, Marine Isotope Stage (MIS) 12 (∼478–424 ka before present) was one of the strongest glacials of the Quaternary. Because the information currently available on MIS 12 is predominantly derived from marine records, the imprint of this extreme glaciation on the terrestrial realm – and notably on terrestrial ecosystems – has remained poorly constrained. Here we present a new, centennial-scale-resolution pollen record from Lake Ohrid (Balkan Peninsula, SE Europe) augmented by pollen-based quantitative temperature and precipitation estimates. Our dataset, which spans the period from 488 to 420 ka, shows that the forest cover around Lake Ohrid decreased substantially over the course of MIS 12; this decrease was associated with a gradual lowering of winter and mean annual temperatures (and to a lesser extent of summer temperatures) as well as mean annual precipitation. Superimposed on this long-term development, abrupt changes in regional forest cover indicate a pronounced millennial-scale climate variability that bears strong resemblance to the interstadial and stadial events of the Last Glacial. This variability is expressed by repeated high-amplitude forest expansions and contractions around Lake Ohrid during MIS 12c and the oldest part of 12b substage (i.e., from ∼477 to 448 ka). The forest oscillations can be correlated to previously documented episodes of surface-water variability and ice-rafted debris deposition in the North Atlantic. This pattern suggests a coupling between the climatically forced tree-population changes in SE Europe and the variability of the Atlantic Meridional Ocean Circulation during MIS 12c and partially 12b on millennial timescales. In contrast, the youngest part of MIS 12b and MIS 12a (i.e., from ∼448 to 424 ka) lack high-amplitude forest expansions and contractions around Lake Ohrid. Comparison with sea-level reconstructions for MIS 12 suggests that millennial-scale vegetation variability in Lake Ohrid was strongest when sea level was between 30 and 100 m lower than today, whereas it was absent when sea level was lower than 100 m relative to the present. © 2019 Elsevier Ltd Article 2019 English 02773791 10.1016/j.quascirev.2019.105873 Quaternary Science Reviews 221 Elsevier Ltd Balkans; Lake Ohrid; Mediterranean Sea; Mediterranean Sea (East); Expansion; Forestry; Glacial geology; Isotopes; Lakes; Sea level; Vegetation; Climate variability; Eastern Mediterranean; Lake Ohrid; Middle Pleistocene; Quantitative climate estimates; Vegetation dynamics; climate change; climate variation; forest cover; glaciation; ice sheet; ice-rafted debris; interstadial; Last Glacial; marine isotope stage; meridional circulation; Pleistocene; sea level; terrestrial ecosystem; vegetation dynamics; Climate change https://www.scopus.com/inward/record.uri?eid=2-s2.0-85071264309&doi=10.1016%2fj.quascirev.2019.105873&partnerID=40&md5=092e2c0f283fe2305bf40d93c4b81d4d Cited by: 14 Andreas Koutsodendris Ilias Kousis Odile Peyron Bernd Wagner Jörg Pross inproceedings matter2019oman 2019 Geophysical Research Abstracts 21 Juerg Matter Peter Kelemen Damon Teagle Jude Coggon article Ledevin2019 The Buck Reef is a 250–400 m thick sequence of banded black and white (B&W) cherts deposited ca. 3416 Ma ago in a shallow basin. We provide field, petrological and geochemical constraints on the chert-forming process and the origin of the banding. White layers consist of nearly pure microquartz, while black layers are mixed with detrital carbonaceous matter, quartz grains and carbonaceous microlaminae, interpreted as remnants of microbial mats. The circulation of Si-rich fluid is recorded by abundant chert veins and pervasive silicification. However, the high purity of the white layers, their lack of internal structures and extremely low Al, Ti and high-field-strength elements preclude an origin by silicification of sedimentary or volcanic precursors. Moreover, their reworking at the surface into slab conglomerates, and sediment-like contacts with black layers rule out a diagenetic origin. We propose a new model whereby the white layers were periodically deposited as precipitates of pure silica; and the micro-layering within the black layers formed by annual temperature fluctuations, favouring microbial activity in summer and inorganic silica precipitation in winter. Outcrop-scale alternation of B&W layers was associated with major, thousand-year-long climate events: white cherts represent massive silica precipitation resulting from changes in ocean circulation and temperature during cold intervals. © 2019 by the authors. Licensee MDPI, Basel, Switzerland. Article 2019 English 20763263 10.3390/geosciences9100424 Geosciences (Switzerland) 9 MDPI AG 10 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85073451902&doi=10.3390%2fgeosciences9100424&partnerID=40&md5=485230dc6fb0c315b84c85de2ca60329 Cited by: 5; All Open Access, Gold Open Access, Green Open Access Morgane Ledevin Nicholas Arndt Catherine Chauvel Etienne Jaillard Alexandre Simionovici article Yang20192133 Natural gas hydrate (NGH) has been widely considered as an alternative form of energy with huge potential, due to its tremendous reserves, cleanness and high energy density. Several countries involving Japan, Canada, India and China have launched national projects on the exploration and exploitation of gas hydrate resources. At the beginning of this century, an early trial production of hydrate resources was carried out in Mallik permafrost region, Canada. Japan has conducted the first field test from marine hydrates in 2013, followed by another trial in 2017. China also made its first trial production from marine hydrate sediments in 2017. Yet the low production efficiency, ice/hydrate regeneration, and sand problems are still commonly encountered; the worldwide progress is far before commercialization. Up to now, many gas production techniques have been proposed, and a few of them have been adopted in the field production tests. Nevertheless, hardly any method appears really promising; each of them shows limitations at certain conditions. Therefore, further efforts should be made on the economic efficiency as well as sustainability and environmental impacts. In this paper, the investigations on NGH exploitation techniques are comprehensively reviewed, involving depressurization, thermal stimulation, chemical inhibitor injection, CO2–CH4 exchange, their combinations, and some novel techniques. The behavior of each method and its further potential in the field test are discussed. The advantages and limitations of laboratory studies are also analyzed. The work could give some guidance in the future formulation of exploitation scheme and evaluation of gas production behavior from hydrate reservoirs. © 2019 Elsevier B.V. 2019 English 10049541 10.1016/j.cjche.2019.02.028 Chinese Journal of Chemical Engineering 27 Materials China 2133-2147 Key Laboratory of Ocean Energy Utilization and Energy Conservation of Ministry of Education, Dalian University of Technology, Dalian, 116024, China; Guangzhou Marine Geological Survey, Guangzhou, 510075, China; China Ship Design & Research Center Co., Ltd., Dalian, 116001, China 9 Carbon dioxide; Environmental impact; Gas industry; Gases; Hydration; Ice problems; Natural gas; Petroleum reservoir evaluation; Production; Proven reserves; Sustainable development, CO2 exchange; Depressurizations; Exploitation techniques; Exploration and exploitation; Gas production technique; Production efficiency; Production techniques; Thermal stimulation, Gas hydrates https://www.scopus.com/inward/record.uri?eid=2-s2.0-85066497415&doi=10.1016%2fj.cjche.2019.02.028&partnerID=40&md5=be9bb9d34c1d06ec19913f2e37dc3db7 cited By 72 L. Yang Y. Liu H. Zhang B. Xiao X. Guo R. Wei L. Xu L. Sun B. Yu S. Leng Y. Li article Wang20191126 收稿日期：2019-04-03；改回日期：2019-09-16 基金项目：中国地质调查局地质调查项目（DD20160207）；国家重点研发专项（2017YFC0601305）及国家自然科学基金青年科学基金项目(41504076)联合资助。作者简介：王天琪，女，1994年生，硕士生，主要从事综合地球物理调查研究工作；E-mail：641149482 @qq.com。通讯作者：韩江涛，男，1982年生，副教授，主要从事深部地球物理勘查工作；E-mail：hanjt@jlu.edu.cn。Abstract: Songliao Basin is a Meso-Cenozoic continental sedimentary basin in Northeast China. Based on a detailed analysis of the Paleozoic stratigraphic characteristics, sedimentary environment and tectonic evolution in Northeast China, the authors conducted the interpretation of the comprehensive geophysical data across Well SK- 2 to investigate the properties and geophysical characteristics of the basement in this paper. On the SN profile, the authors have found some phenomena: the Bouguer gravity anomaly in Well SK-2 is high in the middle and low on both sides; the magnetic anomaly shows a negative correlation with gravity anomaly; magnetotelluric properties are characterized by partial layers and high-low resistance crossover in the shallow part and partial regions in the deep part. On the EW profile, the gravity anomaly curve has the trend high in the west and low in the east; the magnetic anomaly curve is“bowl-shaped”; there exists a high resistance structure compared with features of the SN-trending profile. Combining geophysical characteristics with lithofacies palaeogeography, the authors have reached the following conclusions: 1. From the Late Carboniferous to Late Permian in the Upper Paleozoic, there were many sedimentary environments such as shallow marine facies, continental facies, rivers and lakes. The corresponding lithologic combinations had different physical characteristics; 2. The geomagnetic characteristics of the gravity, magnetic method and magnetotelluric sounding's results reveal that the basement of the study area is mainly composed of mudstone, marble and intrusive rocks, and the burial depth of the roof of the basement is about 7km. The base of the study area is formed by the Upper Paleozoic and intrusive rocks. 3. The location and orientation of the Binzhou fault zone, the Sunwu-Shuangliao fault zone, the Helen-Renmin fault zone and the deep fault system are identified. The fault structures are mainly dominated by SN and EW trending structures. They are important components of the Paleozoic structural skeleton and control the migration and storage of deep oil and gas. © 2019 Editorial Board of Geology in China. All rights reserved. Article 2019 Chinese 10003657 10.12029/gc20190513 Geology in China 46 Science Press 1126 – 1136 5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85104542494&doi=10.12029%2fgc20190513&partnerID=40&md5=a44f66ee925829f3c9d2094e1b85fdc7 Cited by: 4 Tianqi Wang Jiangtao Han Hesheng Hou Wenyu Liu Yanwu Guan Guoqing Ma Zikun Zhou article Jerram201915 To help understand volcanic facies in the subsurface, data sets that enable detailed comparisons between down-hole geophysical data and cored volcanic intervals are critical. However, in many cases, the collection of extended core intervals within volcanic sequences is rare and often incomplete due to challenging coring conditions. In this contribution we outline and provide initial results from borehole logging operations within two fully cored lava-dominated borehole sequences, PTA2 and KMA1, on the Big Island of Hawai`i. Data for spectral gamma, magnetic susceptibility, dipmeter resistivity, sonic, total magnetic field, temperature and televiewer wireline logs were successfully acquired for the open hole interval ca. 889 m to 1567 m within the PTA2 borehole. Spectral gamma was also collected from inside the casing of both wells, extending the coverage for PTA2 to the surface and covering the interval from ca. 300 to 1200 m for KMA1. High-quality core material was available for both boreholes with almost complete recovery which enabled high-resolution core-to-log integration. Gamma data are generally low commonly in the range ca. 7-20 gAPI but are shown to increase up to API of ca. 60 with some intrusions and with increases in hawaiite compositions in the upper part of PTA2. Velocity data are more variable due to alteration within porous volcanic facies than with burial depth, with a general degrease down-hole. The high-resolution televiewer data have been compared directly to the core, enabling a comprehensive analysis of the variations in the televiewer responses. This has enabled the identification of key features including individual vesicles, vesicle segregations, strained vesicles, chilled margins, rubble zones, intrusive contacts and pāhoehoe lobe morphologies, which can be confidently matched between the televiewer data and the full diameter core. The data set and results of this study include findings which should enable improved borehole facies analysis through volcanic sequences in the future, especially where down-borehole data and images but no core are available. © Author(s) 2019. 2019 English 18168957 10.5194/sd-25-15-2019 Scientific Drilling 25 Copernicus GmbH 15-33 CEED, University of Oslo, Oslo, Norway; DougalEARTH, Solihull, United Kingdom; VBPR - Volcanic Basin Petroleum Research, Oslo, Norway; Department of Geology and Petroleum Geology, University of Aberdeen, Aberdeen, United Kingdom; Helmholtz-Zentrum Potsdam, Deutsches GeoForschungsZentrum, Potsdam, Germany; University of Hawai'i at Hilo, 200 W. Kawili St., Hilo, HI 96720-4091, United States; Hawaii Groundwater and Geothermal Resources Center, University of Hawai'i at Manoa, 1680 East West Road, Honolulu, HI 96822, United States; Earth, Environmental and Biological Sciences, Queensland University of Technology, Brisbane, QLD, Australia Coremaking; Image enhancement; Magnetic susceptibility; Thermal logging; Volcanoes, Borehole logging; Comprehensive analysis; Facies analysis; Full diameter core; Geophysical data; High resolution; Volcanic facies; Wireline logging, Boreholes https://www.scopus.com/inward/record.uri?eid=2-s2.0-85067228279&doi=10.5194%2fsd-25-15-2019&partnerID=40&md5=27c65b145c196ae40cda7d0d26191bbe cited By 17 D.A. Jerram J.M. Millett D. Thomas S. Planke E. Haskins N. Lautze S. Pierdominici article Zhang2019147 Latitudinal temperature gradients are a defining characteristic of the climate system. Using thermometric indicators, including δ18O, plant and animal fossils, glycerol dialkyl glycerol tetraether (GDGT) proxies, and clumped isotope estimates, we document marine and terrestrial temperature gradients for the latest Cretaceous, Late Paleocene-Early Eocene, Early Oligocene, Pliocene, and Recent. The changes in gradients reflect the transition greenhouse to icehouse conditions. The evolution of latitudinal temperature gradients in marine and terrestrial realms are similar but has some distinctive differences. Marine temperatures are generally warmer than those on land. Except for the Late Paleocene-Early Eocene, the marine records show distinct inflection points at ~30° and ~50° latitude indicating the existence of frontal systems in the ocean. Except for the Late Paleocene-Early Eocene, the marine records show an increasingly steeper trend, from latest Cretaceous through Recent, being most pronounced after the Early Oligocene greenhouse-icehouse transition. This trend reflects the increasing intensity of high-latitude and polar cooling as the icehouse state developed. During the Late Paleocene-Early Eocene the oceans were characterized by slightly warmer tropics and much warmer higher latitudes than at present. The continents have generally had tropical temperatures like those of today, varying by &lt;5 °C. Higher latitude temperatures cooled during the latest Cretaceous, became much warmer during the Late Paleocene-Early Eocene, then cooled during the Early Oligocene and have become increasingly colder since then. The results suggest that there is a climate thermostat mechanism, probably related to greenhouse gas concentrations, that ameliorates tropical warming by redistributing warmth to the poles in the greenhouse world. That mechanism broke down as greenhouse gas concentrations declined resulting in the conversion from greenhouse to icehouse conditions. © 2019 Elsevier B.V. 2019 English 00128252 10.1016/j.earscirev.2019.01.025 Earth-Science Reviews 189 Elsevier B.V. 147-158 State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences (Beijing), Beijing100083, China; School of Earth Sciences and Resources, China University of Geosciences (Beijing), Beijing100083, China; Department of Geological Sciences and University Museum, University of Colorado at Boulder, 2045 Windcliff Dr, Estes Park, CO 80517, United States climate variation; Cretaceous; glacial-interglacial cycle; greenhouse gas; Oligocene; paleoceanography; Paleocene-Eocene boundary; paleoclimate; Pliocene; temperature gradient; thermometry, Animalia https://www.scopus.com/inward/record.uri?eid=2-s2.0-85060761902&doi=10.1016%2fj.earscirev.2019.01.025&partnerID=40&md5=59b1c3b1251ab72811305de8e7ad5c63 cited By 28 L. Zhang W.W. Hay C. Wang X. Gu article BenDor2019173 The sedimentary record of the Dead Sea provides an exceptional high-resolution archive of past climate changes in the drought-sensitive eastern Mediterranean-Levant, a key region for the development of humankind at the boundary of global climate belts. Moreover, it is the only deep hypersaline lake known to have deposited long sequences of finely laminated, annually deposited sediments (i.e. varves) of varied compositions, including aragonite, gypsum, halite and clastic sediments. Vast efforts have been made over the years to decipher the environmental information stored in these evaporitic-clastic sequences spanning from the Pleistocene Lake Amora to the Holocene Dead Sea. A general characterisation of sediment facies has been derived from exposed sediment sections, as well as from shallow- and deep-water sediment cores. During high lake stands and episodes of positive water budget, mostly during glacial times, alternating aragonite and detritus laminae (‘aad’ facies) were accumulated, whereas during low lake stands and droughts, prevailing during interglacials, laminated detritus (‘ld’ facies) and laminated halite (‘lh’ facies) dominate the sequence. In this paper, we (i) review the three types of laminated sediments of the Dead Sea sedimentary record (‘aad’, ‘ld’ and ‘lh’ facies), (ii) discuss their modes of formation, deposition and accumulation, and their interpretation as varves, and (iii) illustrate how Dead Sea varves are utilized for palaeoclimate reconstructions and for establishing floating chronologies. © 2019 Elsevier Ltd 2019 English 02773791 10.1016/j.quascirev.2019.04.011 Quaternary Science Reviews 215 Elsevier Ltd 173-184 The Hebrew University of Jerusalem, The Fredy and Nadine Herrmann Institute of Earth Sciences, Givat Ram, Jerusalem, 91904, Israel; GFZ German Research Centre for Geosciences, Section Climate Dynamics and Landscape Evolution, Telegrafenberg, Potsdam, 14473, Germany; University of Geneva, Department of Earth Sciences, Rue des Maraichers 13, Geneva, CH-1205, Switzerland; Potsdam University, Department of Earth Sciences, Karl-Liebknecht-Straße 24/25, Potsdam, 14476, Germany Budget control; Carbonate minerals; Chloride minerals; Climate change; Deposition; Drought; Lakes; Sedimentology; Sodium chloride, Deep drilling; Evaporitic varves; Hypersaline lakes; Lacustrine sediments; Palaeoclimate reconstruction; Varve chronologies, Sediments, chronology; deep drilling; drought; global climate; historical record; hypersaline environment; lacustrine deposit; marine sediment; paleoclimate; Pleistocene; reconstruction; sediment core; varve; water budget, Dead Sea; Levant; Mediterranean Region https://www.scopus.com/inward/record.uri?eid=2-s2.0-85066102108&doi=10.1016%2fj.quascirev.2019.04.011&partnerID=40&md5=80dea6b87f37f885c6dcd9632ea3f0b8 cited By 26 Y. Ben Dor I. Neugebauer Y. Enzel M.J. Schwab R. Tjallingii Y. Erel A. Brauer article Hou2019943 With the maturation of oil and gas exploration and development in Songliao basin, it is urgent to expand strategic replacement areas for oil and gas storage and production. In this task，deep oil and gas seem to be an important direction. Roof gas logging with continuous sampling in the whole well section of Well SK-2 obtained 6042 groups of light hydrocarbon composition data containing 103 monomers，and fully demonstrated vertical variation characteristics of light hydrocarbon components in the deep part of Well SK-2，which shows obvious segmentation. As a whole, it can be divided into 6 sections: section I (470-1000 m in well section), which has a small peak area, a small number of peak outfalls, and a low heavy hydrocarbon content, showing the characteristics of shallow and low-mature oil and gas; Section II (well section 1000-2800 m) has a large peak area, a large number of peaks and a high heavy hydrocarbon content. It is a mature type I source rock and a conventional oil and gas section dominated by oil generation; Section III (2800-3320 m in well section) has fewer and scattered peaks, low content of heavy hydrocarbon and no hydrocarbon source rocks, which are characteristic of reservoirs; Section IV (3320- 5940 m in well section) is the upper unconventional gas section of Shahezi Formation, with a large peak area and a large number of peak outputs, high content of heavy hydrocarbon, being Type III source rocks with large thickness in the maturation - over-maturation stage, and sandstone interbeds can form various types of unconventional natural gas, suggesting an important section for future exploration; Section V (5940-6200 m in well section) is the lower part of Shahezi Formation and Huoshiling Formation, and the peak area and peak number of roof gas are scattered within the section which is considered to be in the stage of over-maturation; Section VI (6200-7108 m in well section) is volcanic rock and basement segment, and the peak area and number of peaks are generally low. However, the peak area of top gas in 7000-7100 m well segment shows that the light hydrocarbon parameters are different from those of section V, and it is inferred that there may be gas sources of type II-III organic matter in the deep part. These characteristics show that the vertical distribution of light hydrocarbon components reflects the different characteristics among Jurassic, Cretaceous and the basal formations in oil and gas formation, maturation, gas content and oil and gas sources. The results obtained by the authors reveal the potential of deep unconventional gas resource, and provide an important foundation for Songliao Basin's exploration shift from conventional oil and gas exploration and tight conglomerate gas exploration at the edge of fault depression to deep trough zone for the exploration and expansion of unconventional natural gas. © 2019 Editorial Board of Geology in China. All rights reserved. 2019 Chinese 10003657 10.12029/gc20190501 Geology in China 46 Science Press 943-953 Chinese Academy of Geological Sciences, Beijing, 100037, China; Institute of Exploration Technology, Chinese Academy of Geological Sciences, Hebei, Langfang, 065000, China; Oil and Gas Survey Center of China Geological Survey, Beijing, 100083, China; Key Laboratory of Unconventional Oil and Gas Geology, China Geological Survey, Beijing, 100083, China; No. 1 Logging Company, Daqing Drilling Engineering Co., Ltd., Heilongjiang, Daqing, 163000, China 5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85107629551&doi=10.12029%2fgc20190501&partnerID=40&md5=136c4a56536b37d099c737e8952c29b6 cited By 1 H. Hou J. Zhang W. Wang L. Yang G. Xiao W. Fu H. Miao S. Xu Q. Zeng X. Liu D. Wang W. Zhang article Potter2019736 The Snake River Plain of central Idaho represents the world's best example of a mantle hotspot track impinging upon continental crust and provides a record of bimodal volcanism extending over 12 Ma to the present. Project Hotspot recovered almost 2 km of continuous drill core from the Kimama borehole, located in central Idaho on the axial volcanic zone. The Kimama drill core represents the most complete record of mafic volcanism along the Yellowstone-Snake River Plain hotspot track. A total of 432 basalt flow units, representing 183 basalt flows, 78 basalt flow groups, and 34 super groups, along with 42 sediment interbeds are recognized using volcanic facies observations, stratigraphic relationships, borehole geophysical logs, and paleosecular variation in magnetostratigraphy. Rhyolite and other non-basaltic volcanic materials were not encountered in the drill core. Ages for six basalt lava flows were determined by 40Ar/39 using incremental heating experiments. Paleomagnetic inclination was measured on over 1200 samples collected at roughly 2-m-depth intervals, yielding mean values of paleosecular variation between ±50° to ±70° in Kimama flow groups, close to the expected 61° axial dipole average for the Kimama borehole location. Twenty-three magnetic reversals were identified and correlated to dated geomagnetic chrons and subchrons and compared with the 40Ar/39 radiometric ages. A linear fit to 40Ar/39Ar dates, geomagnetic chron and subchron boundaries, and volcanogenic zircon U-Pb ages defines a mean accumulation rate of ~320 m/m.y. and extrapolates to a bottom hole age of 6.3 Ma. Average thicknesses of lithologic units increase from 2.7 m (sediment), 4 m (flow units), 10 m (flows), 23 m (flow groups), to 53 m (super groups). On average, one lava flow inundated the Kimama borehole location every 33 k.y. Intercalated sediments, ranging from 0.06 to 24.5 m thick, make up roughly 6% of the drill core and indicate lulls in local volcanic activity that may have lasted up to 77 k.y. Neutron and gamma-ray logs supplement observations from the drill cores: neutron logs document individual flow units through the contrast between massive flow interiors and more porous flow surfaces, and gamma-ray logs document the depth and thickness of sedimentary interbeds and high-K-Fe basalts. The 5.8 m.y. duration of basaltic volcanism in the Kimama drill core implies a steady rate of volcanism, indicating a relatively stable rate of mantle upflow along the lithosphere-mantle boundary in the wake of Yellowstone-Snake River Plain plume volcanism. © 2019 The Authors. Article 2019 English 1553040X 10.1130/GES01679.1 Geosphere 15 Geological Society of America 736 – 758 Department of Geology, Utah State University, Logan, UT 84321, United States; Volcano Science Center, U.S. Geological Survey, 345 Middlefield Road, Menlo Park, CA 94025, United States; College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR 97331, United States 3 Idaho; Snake River Plain; United States; Basalt; Binary alloys; Boreholes; Boring; Drills; Gamma rays; Geomagnetism; Infill drilling; Lead alloys; Neutron logging; Plastic flow; Rivers; Sediments; Silicate minerals; Stratigraphy; Uranium alloys; Volcanoes; Zircon; Accumulation rates; Basaltic volcanism; Heating experiment; Lithosphere mantle; Magnetostratigraphy; Paleosecular variations; Snake river plains; Volcanic activities; basalt; borehole; continental crust; facies; lava flow; lithology; magnetic reversal; magnetostratigraphy; paleomagnetism; volcanism; Core drilling https://www.scopus.com/inward/record.uri?eid=2-s2.0-85066821515&doi=10.1130%2fGES01679.1&partnerID=40&md5=ad25ec54bb2b205a9799d084d665e9db Cited by: 3; All Open Access, Gold Open Access, Green Open Access Katherine E. Potter Duane E. Champion Robert A. Duncan John W. Shervais article Billingsley2019 The carbon isotopic ratios of organic matter in fish fossils from diatomites and other lake beds in the HSPDP drill core from Tugen Hills, Kenya (2.56–3.29 Ma) reflect trophic resource uses, and can indicate the dietary habitats of fish in the paleolake. This information offers insight into how fish communities responded to lake-level fluctuations during the Plio-Pleistocene in the East African Rift Valley. We have compared this record with fish fossil isotopes from both a previously published study of a Lake Malawi drill core (139 ka–present) and core top (modern ca 1978) samples collected at the water/sediment boundary from Lake Turkana (Kenya) of known environmental provenance. Both the Lake Malawi drill core fossils (−7.2‰ to −27.5‰ VPDB) and modern Lake Turkana samples (−16‰ to −24.6‰ VPDB) have δ13C values indicating a mix of near-shore and deep-water pelagic species. In contrast, the δ13C values for the Tugen Hills core fossils vary only between −20‰ and −27‰ VPDB. The absence of δ13C values greater than −19‰, suggests none of these fossils are derived from near-shore benthic habitats. The lack of shallow water, benthic lacustrine fish fossils through the Tugen Hills lake cycles may indicate that the rate of change from low-lake stands to deeper lake phases was very rapid, and shallow water communities were not established for long enough to leave a fish fossil record at the core site. These results strongly suggest that lake level responses to climate variability in the Baringo basin of the East African Rift were very abrupt during the Plio-Pleistocene transition. © 2019 Elsevier B.V. Article 2019 English 00310182 10.1016/j.palaeo.2019.109320 Palaeogeography, Palaeoclimatology, Palaeoecology 534 Elsevier B.V. Baringo; East African Lakes; East African Lakes; East African Rift; Kenya; Lake Malawi; Lake Turkana; Tugen Hills; carbon isotope; climate variation; ecosystem response; fish; fossil record; habitat type; lake level; organic matter; paleoclimate; paleoecology; paleoenvironment; Pliocene-Pleistocene boundary; shallow water https://www.scopus.com/inward/record.uri?eid=2-s2.0-85071076934&doi=10.1016%2fj.palaeo.2019.109320&partnerID=40&md5=9c875d6b823477268a227ae8d2013b5c Cited by: 1 Anne L. Billingsley Peter Reinthal David L. Dettman John D. Kingston Alan L. Deino Kevin Ortiz Benjamin Mohler Andrew S. Cohen article 2019 2019 中国地质 46 中国地质 1200-1208 5 李立鑫 张丰琰 张恒春 汪伟 张毅 胡郁乐 article Fedorov2019516 Article 2019 10.1111/bor.12367 Boreas 48 516 – 533 2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85058865359&doi=10.1111%2fbor.12367&partnerID=40&md5=e29915a35f4cdc69de06aa7ef7341ea2 Cited by: 8 Grigory Fedorov Andrei A. Andreev Elena Raschke Volker Wennrich Georg Schwamborn Olga Y. Glushkova Olaf Juschus Anja Zander Martin Melles article Gulick201919342 Highly expanded Cretaceous-Paleogene (K-Pg) boundary section from the Chicxulub peak ring, recovered by International Ocean Discovery Program (IODP)-International Continental Scientific Drilling Program (ICDP) Expedition 364, provides an unprecedented window into the immediate aftermath of the impact. Site M0077 includes ∼130 m of impact melt rock and suevite deposited the first day of the Cenozoic covered by <1 m of micrite-rich carbonate deposited over subsequent weeks to years. We present an interpreted series of events based on analyses of these drill cores. Within minutes of the impact, centrally uplifted basement rock collapsed outward to forma peak ring capped in melt rock. Within tens of minutes, the peak ring was covered in ∼40 m of brecciated impact melt rock and coarsegrained suevite, including clasts possibly generated by melt-water interactions during ocean resurge. Within an hour, resurge crested the peak ring, depositing a 10-m-thick layer of suevite with increased particle roundness and sorting.Within hours, the full resurge deposit formed through settling and seiches, resulting in an 80-m-thick fining-upward, sorted suevite in the flooded crater. Within a day, the reflected rim-wave tsunami reached the crater, depositing a cross-bedded sand-to-fine gravel layer enriched in polycyclic aromatic hydrocarbons overlain by charcoal fragments. Generation of a deep crater open to the ocean allowed rapid flooding and sediment accumulation rates among the highest known in the geologic record. The high-resolution section provides insight into the impact environmental effects, including charcoal as evidence for impactinduced wildfires and a paucity of sulfur-rich evaporites from the target supporting rapid global cooling and darkness as extinction mechanisms. © 2019 National Academy of Sciences. All rights reserved. 2019 10.1073/pnas.1909479116 Proceedings of the National Academy of Sciences of the United States of America 116 19342-19351 Institute for Geophysics, Jackson School of Geosciences, University of Texas at Austin, Austin, TX 78758, United States; Department of Geological Sciences, Jackson School of Geosciences, University of Texas at Austin, Austin, TX 79712, United States; Department of Geosciences, Pennsylvania State University, University Park, PA 16801, United States; Centro de Astrobiologia Instituto Nacional de Tecnica Aeroespacial-Spanish National Research Council, Instituto Nacional de Técnica Aeroespacial, Torrejon de Ardoz, 28850, Spain; Enthought, Inc., Austin, TX 78701, United States; Western Australian Organic and Isotope Geochemistry Centre, Institute for Geoscience Research, School of Earth and Planetary Science, Curtin University, Perth, WA 6102, Australia; Department of Earth Science and Engineering, Imperial College London, London, SW7 2AZ, United Kingdom; Planetary Science Institute, Tucson, AZ 85719-2395, United States; Analytical, Environmental and Geo-Chemistry, Vrije Universiteit Brussel, Pleinlaan 2, Brussels, B-1050, Belgium; Department of Geosciences, University of Alaska Fairbanks, Fairbanks, AK 99775, United States; Department of Earth and Planetary Sciences, Rutgers University, New Brunswick, NJ 08854, United States; International Research Institute of Disaster Science, Tohoku University, Sendai, 980-8572, Japan; Department of Earth Sciences, University of Western Ontario, London, ON N6A 3K7, Canada; Institut für Geologie, Universität Hamburg, Hamburg, 20146, Germany; Faculty of Earth and Life Sciences (FALW), Vrije Universiteit Amsterdam, Amsterdam, 1081 HV, Netherlands; Swedish Museum of Natural History, Stockholm, 114 18, Sweden; Eyring Materials Center, Arizona State University, Tempe, AZ 85287-1704, United States 39 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85072638126&doi=10.1073%2fpnas.1909479116&partnerID=40&md5=9e9ef9ec1b056adbd8f5d307962f49bb cited By 79 S.P.S. Gulick T.J. Bralower J. Ormö K. Grice B. Schaefer S. Lyons K.H. Freeman J.V. Morgan N. Artemieva P. Kaskes S.J. De Graaff M.T. Whalen G.S. Collins S.M. Tikoo C. Verhagen G.L. Christeson P. Claeys M.J.L. Coolen S. Goderis K. Goto R.A.F. Grieve N. McCall G.R. Osinski A.S.P. Rae U. Riller J. Smit V. Vajda A. Wittmann article francke2019tgfl Geochemical finger print data (in wt. {%}) of individual glass shards from 3 three previously described cryptotephra layer in the Late Glacial to Holocene sediments of the DEEP site sequence. FeO? is reported for both Fe${^2}$? and Fe${^3}$? (University of Cologne, Germany , University of Pisa, Italy). 2019 10.1594/PANGAEA.899325 PANGAEA PANGAEA https://doi.org/10.1594/PANGAEA.899325 In supplement to: Francke, A et al. (2019): Sediment residence time reveals Holocene shift from climatic to vegetation control on catchment erosion in the Balkans. Global and Planetary Change, 177, 186-200, https://doi.org/10.1016/j.gloplacha.2019.04.005 Alexander Francke Anthony Dosseto Konstantinos Panagiotopoulos Niklas Leicher Jack H Lacey Styliani Kyrikou Bernd Wagner Giovanni Zanchetta Katerina Kouli Melanie J Leng article McCormack2019167 Oxygen and carbon isotope (δ 18 O and δ 13 C) data from bulk carbonates are widely applied proxies for temperature, the precipitation/evaporation ratio and productivity in lacustrine palaeohydrology and palaeoclimatology. In case of the terminal and alkaline Lake Van, however, previous studies have shown that bulk oxygen isotope compositions are in disagreement with other proxies when interpreted in a conventional manner. Similarly, the reports on the nature and the timing and site of carbonate precipitation in Lake Van are inconsistent. This study provides evidence on the mineralogy (X-ray powder diffraction analysis, scanning electron microscope imaging, confocal Raman microscopy, electron microprobe analysis) and isotope composition (δ 18 O and δ 13 C) of non-skeletal carbonate minerals in a Lake Van sedimentary profile spanning the last ca. 150 kyr. Carbonate phases present in the sediment include aragonite, low-Mg calcite, and calcian dolomite. Dolomite forms as an early diagenetic phase and occurs episodically in high concentrations driving the bulk isotope record towards the higher dolomite δ 18 O and varying δ 13 C values. Aragonite and low-Mg calcite precipitate in the surface water and are present in the sediments in varying amounts (relative aragonite to calcite content for dolomite-poor samples Ar/(Ar + Cc) of 93 to 41 wt%). In an attempt to explain this variation, we revised a precipitation model based on annually laminated sediments containing both aragonite and calcite spatially separated in light and dark coloured laminae, respectively. According to our model, spring calcite precipitation, under close-to-freshwater conditions, is followed by evapoconcentration-driven aragonite precipitation in late summer. The precipitation of these carbonate polymorphs from chemically differing surface waters (i.e. freshwater-influenced and evapoconcentrated) leads to distinctly different oxygen and carbon isotope signatures between sedimentary penecontemporaneous aragonite and calcite. The δ 18 O and δ 13 C values of aragonite relative to calcite are significantly higher by several per mille than inferred from aragonite-calcite fractionation factors alone, suggesting that the generalised assumption of sedimentary coeval calcite and aragonite precipitating from water with the same isotopic composition is flawed. The here proposed revised hydrologically-separated carbonate precipitation model is not only taking (i) differences in the isotopic fractionation between carbonate minerals into account, but also (ii) considering the hydrological conditions and the processes favouring the precipitation of a given mineral and ultimately controlling its isotopic composition. If mixed mineralogies are present, this mineralogy-specific approach has the potential of refining environmental reconstructions and reconciling apparently equivocal interpretations of different proxy records. © 2019 The Authors 2019 English 00092541 10.1016/j.chemgeo.2019.03.014 Chemical Geology 513 Elsevier B.V. 167-183 Department of Geology, Mineralogy and Geophysics, Ruhr University Bochum, Bochum, 44801, Germany; Alfred Wegener Institut, Helmholtz Zentrum für Polar und Meeresforschung, Bremerhaven, 27570, Germany Calcite; Carbon; Carbonation; Electron probe microanalysis; Isotopes; Lakes; Oxygen; Refining; Repair; Scanning electron microscopy; Sedimentology; Sediments; Water; X ray powder diffraction, Carbonate precipitation; Confocal Raman microscopy; Diagenetics; Environmental reconstruction; Isotopic fractionations; Lake vans; Oxygen isotope composition; Palaeoenvironmental reconstruction, Carbonate minerals, aragonite; calcite; carbon isotope; carbonate; diagenesis; dolomite; isotopic composition; lacustrine deposit; mineralogy; oxygen isotope; paleoenvironment; reconstruction; sediment chemistry, Lake Van; Turkey https://www.scopus.com/inward/record.uri?eid=2-s2.0-85063198079&doi=10.1016%2fj.chemgeo.2019.03.014&partnerID=40&md5=bd89ff8a1867259f7e458b1780cf340d cited By 18 J. McCormack G. Nehrke N. Jöns A. Immenhauser O. Kwiecien article Francke2019186 Understanding the evolution of soil systems on geological time scales has become fundamentally important to predict future landscape development in light of rapid global warming and intensifying anthropogenic impact. Here, we use an innovative uranium isotope-based technique combined with organic carbon isotopes and elemental ratios of sediments from Lake Ohrid (North Macedonia/Albania) to reconstruct soil system evolution in the lake's catchment during the last ~16,000 cal yr BP. Uranium isotopes are used to estimated the paleo-sediment residence time, defined as the time elapsed between formation of silt and clay sized detrital matter and final deposition. The chronology is based on new cryptotephra layers identified in the sediment sequence. The isotope and elemental data are compared to sedimentary properties and pollen from the same sample material to provide a better understanding of past catchment erosion and landscape evolution in the light of climate forcing, vegetation development, and anthropogenic land use. During the Late Glacial and the Early Holocene, when wide parts of the catchment were covered by open vegetation, wetter climates promoted the mobilisation of detrital matter with a short paleo-sediment residence time. This is explained by erosion of deeper parts of the weathering horizon from thin soils. Detrital matter with a longer paleo-sediment residence time, illustrating shallow erosion of thicker soils is deposited in drier climates. The coupling between climatic variations and soil erosion terminates at the Early to Mid-Holocene transition as evidenced by a pronounced shift in uranium isotope ratios indicating that catchment erosion is dominated by shallow erosion of thick soils only. This shift suggests a threshold is crossed in hillslope erosion, possibly as a result of a major change in vegetation cover preventing deep erosion of thin soils at higher elevation. The threshold in catchment erosion is not mirrored by soil development over time, which gradually increases in response to Late Glacial to Holocene warming until human land use during the Late Holocene promotes reduced soil development and soil degradation. Overall, we observe that soil system evolution is progressively controlled by climatic, vegetation, and eventually by human land use over the last ~16,000 years. © 2019 Elsevier B.V. 2019 English 09218181 10.1016/j.gloplacha.2019.04.005 Global and Planetary Change 177 Elsevier B.V. 186-200 Wollongong Isotope Geochronology Laboratory, School of Earth, Atmospheric and Life Sciences, University of Wollongong, Wollongong, NSW 2522, Australia; GeoQuEST Research Centre, School of Earth, Atmospheric and Life Sciences, University of Wollongong, Wollongong, NSW 2522, Australia; Institute of Geology and Mineralogy, University of Cologne, Cologne, 50674, Germany; NERC Stable Isotope Facility, British Geological Survey, Nottingham, NG12 5GG, United Kingdom; Department of Geology and Geoenvironment, National and Kapodistrian University of Athens, Athens, 15784, Greece; Deparment of Earth Sciences, University of Pisa, Pisa, 56126, Italy; Centre for Environmental Geochemistry, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, LE12 5RD, United Kingdom Catchments; Erosion; Geomorphology; Glacial geology; Global warming; Isotopes; Lakes; Land use; Nuclear fuels; Organic carbon; Runoff; Sediments; Uranium; Vegetation, Balkan peninsulas; Human impact; Lake Ohrid; Landscape evolutions; Paleoclimates; Residence time; Soil systems; Tephrochronology; Uranium isotopes, Soils, catchment; detrital deposit; geomorphology; global warming; Holocene; landscape evolution; organic carbon; residence time; sediment analysis; soil erosion; tephrochronology; uranium isotope; vegetation cover; weathering rate, Albania; Balkans; Greece; Lake Ohrid; Macedonia [Greece] https://www.scopus.com/inward/record.uri?eid=2-s2.0-85064183230&doi=10.1016%2fj.gloplacha.2019.04.005&partnerID=40&md5=c136e8f3b26f68f271e28816860b4ba3 cited By 21 A. Francke A. Dosseto K. Panagiotopoulos N. Leicher J.H. Lacey S. Kyrikou B. Wagner G. Zanchetta K. Kouli M.J. Leng article Smith2019137 This paper presents a detailed record of volcanism extending back to ∼80 kyr BP for southern South America using the sediments of Laguna Potrok Aike (ICDP expedition 5022; Potrok Aike Maar Lake Sediment Archive Drilling Project - PASADO). Our analysis of tephra includes the morphology of glass, the mineral componentry, the abundance of glass-shards, lithics and minerals, and the composition of glass-shards in relation to the stratigraphy. Firstly, a reference database of glass compositions of known eruptions in the region was created to enable robust tephra correlations. This includes data published elsewhere, in addition to new glass-shard analyses of proximal tephra deposits from Hudson (eruption units H1 and H2), Aguilera (A1), Reclus (R1, R2-3), Mt Burney (MB1, MB2, MBx, MB1910) and historical Lautaro/Viedma deposits. The analysis of the ninety-four tephra layers observed in the Laguna Potrok Aike sedimentary sequence reveals that twenty-five tephra deposits in the record are the result of primary fallout and are sourced from at least three different volcanoes in the Austral Andean Volcanic Zone (Mt Burney, Reclus, Lautaro/Viedma) and one in the southernmost Southern Volcanic Zone (Hudson). One new correlation to the widespread H1 eruption from Hudson volcano at 8.7 (8.6–9.0) cal ka BP during the Quaternary is identified. The identification of sixty-five discrete deposits that were predominantly volcanic ashes (glass and minerals) with subtle characteristics of reworking (in addition to three likely reworked tephra, and one unknown layer) indicates that care must be taken in the analysis of both visible and invisible tephra layers to decipher their emplacement mechanisms. © 2019 The Authors Article 2019 10.1016/j.quascirev.2019.06.001 Quaternary Science Reviews 218 137 – 156 Argentina; Laguna Potrok Aike; Patagonia; Santa Cruz [Argentina]; Southern Volcanic Zone; Deposits; Geochemistry; Glass; Minerals; Sedimentology; Stratigraphy; Lacustrine; PASADO; Patagonia; Quaternary; South America; Tephrochronology; Volcanic ash; emplacement; geochemistry; lacustrine environment; Quaternary; reworking; sediment chemistry; sedimentary sequence; stratigraphy; tephrochronology; volcanic ash; volcanic eruption; volcanism; volcano; Volcanoes https://www.scopus.com/inward/record.uri?eid=2-s2.0-85067901780&doi=10.1016%2fj.quascirev.2019.06.001&partnerID=40&md5=0afe91df0b53c38bfb1ea5b72da75afc Cited by: 8; All Open Access, Green Open Access, Hybrid Gold Open Access Rebecca E. Smith Victoria C. Smith Karen Fontijn Stefan Wastegård Bernd Zolitschka Christian Ohlendorf Charles Stern Christoph Mayr article Gurov20192532 Remnants of paleoflora were discovered in impact melt rocks from the El'gygytgyn crater, Chukotka, Russia. El'gygytgyn is a 3.58 Ma, 18 km diameter impact structure in Chukotka, northeastern Russia. A circular crater basin is surrounded by an uplifted rim. The crater floor is occupied by the El'gygytgyn Lake, 12 km in diameter, surrounded by lacustrine terraces up to 80 m in height. Impactites found at the El'gygytgyn crater include impact melt rocks, glass bombs, and shock metamorphosed volcanic rocks. Most impact melt rocks occur only in redeposited state in the terrace lake deposits. Floral remnants were discovered in impact melt rocks from various locations in the terrace deposits. The floral remnants include fragments of leaves, cell tissue, and undetermined organic matter that occur in vesicles within glassy melt rocks and impact melt breccias. After the discovery of floral remnants in impact melt breccias from upper Miocene strata in Argentina, and the description of floral imprints in the Dakhleh Glass of proposed impact origin in Egypt, the detection of paleoflora remnants in impact melt rocks of the El'gygytgyn structure is the first such occurrence in a confirmed impact crater on Earth. © 2019 The Authors. Meteoritics & Planetary Science published by Wiley Periodicals, Inc. on behalf of The Meteoritical Society (MET). 2019 English 10869379 10.1111/maps.13241 Meteoritics and Planetary Science 54 University of Arkansas 2532-2540 Institute of Geological Sciences, National Academy of Sciences of Ukraine, Gontchara Str., 55b, Kiev, Ukraine; Department of Lithospheric Research, University of Vienna, Althanstrasse 14, Vienna, A-1090, Austria; Natural History Museum, Burgring, Vienna, A-1010, Austria 10 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85060552517&doi=10.1111%2fmaps.13241&partnerID=40&md5=64fdd3f902f26b8658d4efbde4c03dd4 cited By 3 E.P. Gurov V.V. Permiakov C. Koeberl article Hu20191193 Well Songke-2 is the deepest continental scientific drilling carried out by Asian countries. The logging temperature of Well Songke-2 Songke-2 was 241 °C after drilling for 38 hours, which created the highest well temperature application record of drilling engineering in China. The parameters of Well Songke-2 are mainly tested in two ways: one is integrated logging before casing, whereas the other is downhole parameter measurement while drilling which does not affect normal drilling work. Timely grasping the information such as the temperature while drilling plays a key supporting role in the adjustment of high temperature mud performance and the application of power tools. The authors carried out a series of researches on the problem of high temperature in Well Songke-2, and developed a storage type measurement while drilling instrument. The instrument was improved and designed through multiple rounds of research and finally it has been successfully applied to Well Songke-2. © 2019 Editorial Board of Geology in China. All rights reserved. Article 2019 Chinese 10003657 10.12029/gc20190519 Geology in China 46 Science Press 1193 – 1199 5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85107682202&doi=10.12029%2fgc20190519&partnerID=40&md5=cdd64dfdc84d70712bb8ac29d2e884b5 Cited by: 3 Yule Hu Naipeng Liu Wei Wang Hengchun Zhang article Palermo2019204 Article 2019 10.1016/j.jsames.2018.11.028 Journal of South American Earth Sciences 90 204 – 215 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85058949433&doi=10.1016%2fj.jsames.2018.11.028&partnerID=40&md5=221f1e780c8de5c553cf074960ff05b0 Cited by: 7 Pedro Palermo Mariá A. Irurzun Claudia S.G. Gogorza Ana M. Sinito Christian Ohlendorf Bernd Zolitschka article Gulick2019157 Shorelines are ephemeral features, yet many science problems cross this ever-moving boundary and require sampling on both its dry and wet sides. The logistics of working on land and at sea are distinct, such that funding agencies in many countries divide their research programs at the shoreline. Similarly, scientific drilling is split between the International Ocean Discovery Program (IODP) in the ocean and the International Continental Scientific Drilling Program (ICDP) on land. Here, we discuss three examples of drilling projects that effectively coordinated activities between IODP and ICDP and highlight the need for increasing cooperation and coordination across the shoreline. We end by casting an eye toward the future of scientific drilling, where truly amphibious projects are now possible. © 2019 The Oceanography Society, Inc. 2019 English 10428275 10.5670/oceanog.2019.139 Oceanography 32 Oceanography Society 157-159 Institute for Geophysics, Department of Geological Sciences, Jackson School of Geosciences, The University of Texas at Austin, Austin, TX, United States; Department of Earth and Planetary Sciences, Rutgers University, Piscataway, NJ, United States; Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY, United States; Department of Earth Science and Engineering, Imperial College London, London, United Kingdom; Géosciences Rennes, Université de Rennes 1, Rennes, France; Department of Geology, Faculty of Science, Niigata University, Research and Development Center for Ocean Drilling Science, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Japan 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85066038967&doi=10.5670%2foceanog.2019.139&partnerID=40&md5=161ad26af297d7363c834c5e3041dcca cited By 1 S.P.S. Gulick K. Miller P. Kelemen J. Morgan J.-N. Proust E. Takazawa article Brown20191 The primary scientific objective of MexiDrill, the Basin of Mexico Drilling Program, is development of a continuous, high-resolution <span classCombining double low line"inline-formula ∼4400kyr lacustrine record of tropical North American environmental change. The field location, in the densely populated, water-stressed Mexico City region gives this record particular societal relevance. A detailed paleoclimate reconstruction from central Mexico will enhance our understanding of long-term natural climate variability in the North American tropics and its relationship with changes at higher latitudes. The site lies at the northern margin of the Intertropical Convergence Zone (ITCZ), where modern precipitation amounts are influenced by sea surface temperatures in the Pacific and Atlantic basins. During the Last Glacial Maximum (LGM), more winter precipitation at the site is hypothesized to have been a consequence of a southward displacement of the mid-latitude westerlies. It thus represents a key spatial node for understanding large-scale hydrological variability of tropical and subtropical North America and is at an altitude (2240 a.s.l.), typical of much of western North America. In addition, its sediments contain a rich record of pre-Holocene volcanic history; knowledge of the magnitude and frequency relationships of the area's explosive volcanic eruptions will improve capacity for risk assessment of future activity. Explosive eruption deposits will also be used to provide the backbone of a robust chronology necessary for full exploitation of the paleoclimate record. Here we report initial results from, and outreach activities of, the 2016 coring campaign. © Author(s) 2019. 2019 English 18168957 10.5194/sd-26-1-2019 Scientific Drilling 26 Copernicus GmbH 1-15 Large Lakes Observatory and Dept. of Earth and Environmental Sciences, University of Minnesota Duluth, Duluth, MN 55812, United States; Instituto de Geofísica, Universidad Nacional Autónoma de México, Mexico City, 04510, Mexico; Department of Earth and Planetary Science, University of New Mexico, Albuquerque, NM 87131, United States; Instituto de Geología, Universidad Nacional Autónoma de México, Mexico City, 04510, Mexico; Institut für Geosysteme und Bioindikation, Technische Universität Braunschweig, Braunschweig, 38106, Germany; Research Laboratory for Archaeology and the History of Art, University of Oxford, Oxford, OX1 3TG, United Kingdom; Instituto Pirenaico de Ecología, Agencia Consejo Superior de Investigaciones Científicas, Avda Montañana 1005, Zaragoza, 50059, Spain; School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, B15 2TT, United Kingdom; Department of Geology and Environmental Science, University of Pittsburgh, Pittsburgh, PA 15260, United States; Leibniz-Institut für Angewandte Geophysik, Stilleweg 2, Hannover, 30655, Germany; LacCore and Continental Scientific Drilling Coordination Office, Department of Earth Sciences, University of Minnesota Twin Cities, Minneapolis, MN 55455, United States; Instituto de Geología, Universidad Nacional Autónoma de México, Cd. de México, 04510, Mexico; Instituto de Geofísica, Universidad Nacional Autónoma de México, Cd. de México, 04510, Mexico; Large Lakes Observatory and Dept of Earth and Environmental Sciences, University of Minnesota Duluth, Duluth, MN 55812, United States; Department of Geosciences, Pennsylvania State University, University Park, PA 16802, United States; Leibniz Institute of Applied Geophysics, Stilleweg 2, Hannover, 30655, Germany; Deutsches GeoForschungsZentrum, Helmholtz-Zentrum Potsdam, Geomikrobiologie, Potsdam, 14473, Germany; Department of Geosciences, University of Arizona, Tucson, AZ 85719, United States; Institut für Geo-und Umweltnaturwissenschaften, Albert-Ludwigs-Universität Freiburg, Freiburg, 79104, Germany; Department of Earth Sciences, University of Oxford, Oxford, OX1 3AN, United Kingdom Explosives; Infill drilling; Oceanography; Risk assessment; Surface waters; Volcanoes, Environmental change; Hydrological variability; Intertropical convergence zone; Natural climate variabilities; Paleoclimate reconstruction; Paleoclimate records; Scientific objectives; Sea surface temperature (SST), Tropics https://www.scopus.com/inward/record.uri?eid=2-s2.0-85076097631&doi=10.5194%2fsd-26-1-2019&partnerID=40&md5=868fbde0b595a248576347b1b13030a2 cited By 11 E.T. Brown M. Caballero E. Cabral Cano P.J. Fawcett S. Lozano-García B. Ortega L. Pérez A. Schwalb V. Smith B.A. Steinman M. Stockhecke B. Valero-Garcés S. Watt N.J. Wattrus J.P. Werne T. Wonik A.E. Myrbo A.J. Noren R. O'Grady D. Schnurrenberger R.M. Abarca A.O. Beltrán C. Caballero L. Cappio R. Cossio T. Ferland K. Hesse J. Kallmeyer D. Kumar S.G. Leon I. Martínez C.A. Noriega F. Preusser H. Rawson A.M. Soler S. Sosa-Nájera D.A. Villeda C. Zeeden article Riedel201917 Numerical modelling of fluid flow and transport processes relies on a well-constrained geological model, which is usually provided by seismic reflection surveys. In the New Jersey shelf area a large number of 2D seismic profiles provide an extensive database for constructing a reliable geological model. However, for the purpose of modelling groundwater flow, the seismic data need to be depth-converted which is usually accomplished using complementary data from borehole logs. Due to the limited availability of such data in the New Jersey shelf, we propose a two-stage processing strategy with particular emphasis on reflection tomography and pre-stack depth imaging. We apply this workflow to a seismic section crossing the entire New Jersey shelf. Due to the tomography-based velocity modelling, the processing flow does not depend on the availability of borehole logging data. Nonetheless, we validate our results by comparing the migrated depths of selected geological horizons to borehole core data from the IODP expedition 313 drill sites, located at three positions along our seismic line. The comparison yields that in the top 450 m of the migrated section, most of the selected reflectors were positioned with an accuracy close to the seismic resolution limit (≈ 4 m) for that data. For deeper layers the accuracy still remains within one seismic wavelength for the majority of the tested horizons. These results demonstrate that the processed seismic data provide a reliable basis for constructing a hydrogeological model. Furthermore, the proposed workflow can be applied to other seismic profiles in the New Jersey shelf, which will lead to an even better constrained model. © 2018, Springer Science+Business Media B.V., part of Springer Nature. 2019 English 00253235 10.1007/s11001-018-9360-9 Marine Geophysical Research 40 Springer Netherlands 17-32 Department of Geosciences and Geography, University of Helsinki, P.O. Box 68, Helsinki, 00014, Finland; Institute for Applied Geophysics and Geothermal Energy, RWTH Aachen University, Mathieustraße 10, Aachen, 52074, Germany; Institute of Geophysics and Geoinformatics, Technische Universität Bergakademie Freiberg, Gustav-Zeuner-Straße 12, Freiberg, 09596, Germany 1 Geologic models; Geophysical prospecting; Groundwater; Groundwater flow; Seismic response; Tomography; Well logging, Complementary data; Geological modeling; Groundwater modelling; Hydrogeological models; Seismic imaging; Seismic reflection survey; Seismic resolution; Two-stage processing, Seismic waves, borehole logging; groundwater flow; imaging method; numerical model; Ocean Drilling Program; seismic data; seismic tomography; seismic velocity, Atlantic Ocean; New Jersey Shelf https://www.scopus.com/inward/record.uri?eid=2-s2.0-85047916542&doi=10.1007%2fs11001-018-9360-9&partnerID=40&md5=18b3a7584c6ffcb65620c99c4f023d3c cited By 4 M. Riedel S. Reiche K. Aßhoff S. Buske article Jackson201935 The 2017 Surtsey Underwater volcanic System for Thermophiles, Alteration processes and INnovative concretes (SUSTAIN) drilling project at Surtsey volcano, sponsored in part by the International Continental Scientific Drilling Program (ICDP), provides precise observations of the hydrothermal, geochemical, geomagnetic, and microbiological changes that have occurred in basaltic tephra and minor intrusions since explosive and effusive eruptions produced the oceanic island in 1963-1967. Two vertically cored boreholes, to 152 and 192m below the surface, were drilled using filtered, UV-sterilized seawater circulating fluid to minimize microbial contamination. These cores parallel a 181m core drilled in 1979. Introductory investigations indicate changes in material properties and whole-rock compositions over the past 38 years. A Surtsey subsurface observatory installed to 181m in one vertical borehole holds incubation experiments that monitor in situ mineralogical and microbial alteration processes at 25-124 °C. A third cored borehole, inclined 55° in a 264° azimuthal direction to 354m measured depth, provides further insights into eruption processes, including the presence of a diatreme that extends at least 100m into the seafloor beneath the Surtur crater. The SUSTAIN project provides the first time-lapse drilling record into a very young oceanic basaltic volcano over a range of temperatures, 25-141 °C from 1979 to 2017, and subaerial and submarine hydrothermal fluid compositions. Rigorous procedures undertaken during the drilling operation protected the sensitive environment of the Surtsey Natural Preserve. © Author(s) 2019. 2019 English 18168957 10.5194/sd-25-35-2019 Scientific Drilling 25 Copernicus GmbH 35-46 Department of Geology and Geophysics, University of Utah, Salt Lake City, UT, United States; Nordvulk, Institute of Earth Sciences, University of Iceland, Reykjavík, Iceland; ÍSOR, Iceland GeoSurvey, Reykjavík, Iceland; Department of Geosciences, University of Massachusetts, Amherst, MA, United States; Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences, Potsdam, Germany; Matís, Exploration and Utilization of Genetic Resources, Reykjavík, Iceland; Faculty of Food Science and Nutrition, University of Iceland, Reykjavík, Iceland; Department of Geosciences and MARUM, University of Bremen, Bremen, Germany; Geothermal Research Cluster (GEORG), Reykjavik, Iceland; Faculty of Life and Environmental Sciences, University of Iceland, Reykjavík, Iceland; University of New Hampshire, Durham, NH, United States; Dipartimento di Scienze della Terra, Dell'Ambiente e delle Risorse (DiSTAR), University FEDERICO II, Naples, Italy; Jartaeknistofan, (GEOICE Geological Services Ltd), Hafnarfjörur, Iceland; K.G. Jebsen Centre for Deep Sea Research, Department of Earth Science, University of Bergen, Bergen, Norway; Collections and Systematics Department, Icelandic Institute of Natural History, Gardabaer, Iceland; DOSECC Exploration Services, Salt Lake City, UT, United States; School of Natural Sciences, University of Tasmania, Hobart, Australia; U.S. Geological Survey, Menlo Park, CA, United States; Verkís Consulting Engineers, Reykjavík, Iceland; Geology Department, University of Otago, Dunedin, New Zealand; Institut für Geographie und Geologie, Universität Würzburg, Würzburg, Germany Boreholes; Boring; Geomagnetism; Infill drilling; Volcanoes, Azimuthal direction; Circulating fluids; Continental scientific drillings; Drilling operation; Effusive eruptions; Hydrothermal fluids; Microbial contamination; Vertical borehole, Core drilling https://www.scopus.com/inward/record.uri?eid=2-s2.0-85067234867&doi=10.5194%2fsd-25-35-2019&partnerID=40&md5=9443f9b2fad29113ee485c819dfd8013 cited By 13 M.D. Jackson M.T. Gudmundsson T.B. Weisenberger J. Michael Rhodes A. Stefánsson B.I. Kleine P.C. Lippert J.M. Marquardt H.I. Reynolds V.T. Marteinsson P. Vannier W. Bach A. Barich P. Bergsten J.G. Bryce P. Cappelletti S. Couper M.F. Fahnestock C.F. Gorny C. Grimaldi M. Groh Á. Gudmundsson Á.T. Gunnlaugsson C. Hamlin T. Högnadóttir K. Jónasson S.S. Jónsson S.L. Jørgensen A.M. Klonowski B. Marshall E. Massey J. McPhie J.G. Moore E.S. Ólafsson S.L. Onstad V. Perez S. Prause S.P. Snorrason A. Türke J.D. White B. Zimanowski article Lellouch20196931 Structural imaging and event location require an accurate estimation of the seismic velocity. However, active seismic surveys used to estimate it are expensive and time-consuming. During the last decade, fiber-optic-based distributed acoustic sensing has emerged as a reliable, enduring, and high-resolution seismic sensing technology. We show how downhole distributed acoustic sensing passive records from the San Andreas Fault Observatory at Depth can be used for seismic velocity estimation. Using data recorded from earthquakes propagating near-vertically, we compute seismic velocities using first-break picking as well as slant stack decomposition. This methodology allows for the estimation of both P and S wave velocity models. We also use records of the ambient seismic field for interferometry and P wave velocity model extraction. Results are compared to a regional model obtained from surface seismic as well as a conventional downhole geophone survey. We find that using recorded earthquakes, we obtain the highest P wave model resolution. In addition, it is the only method that allows for S wave velocity estimation. Computed P and S models unravel three distinct areas at the depth range of 50-750 m, which were not present in the regional model. In addition, we find high VP/VS values near the surface and a possible VP/VS anomaly about 500 m deep. We confirm its existence by observing a strong S-P mode conversion at that depth. ©2019. American Geophysical Union. All Rights Reserved. 2019 English 21699313 10.1029/2019JB017533 Journal of Geophysical Research: Solid Earth 124 Blackwell Publishing Ltd 6931-6948 Department of Geophysics, Stanford University, Stanford, CA, United States; Now at Earthquake Research Institute, The University of Tokyo, Tokyo, Japan 7 acoustic survey; borehole geophysics; estimation method; geophone; P-wave; S-wave; San Andreas Fault; seismic velocity, California; San Andreas; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-85069939400&doi=10.1029%2f2019JB017533&partnerID=40&md5=ab4848f914466d2ea7532baaee9dbf79 cited By 40 A. Lellouch S. Yuan Z. Spica B. Biondi W.L. Ellsworth article Martínez-Garzón2019209 We analyze a large transient strainmeter signal recorded at 62.5 m depth along the southern shore of the eastern Sea of Marmara region in northwestern Turkey. This region represents a passage of stress transfer from the Izmit rupture to the Marmara seismic gap. The strain signal was recorded at the Esenkoy site by one of the ICDP-GONAF (International Continental Drilling Programme – Geophysical Observatory at the North Anatolian Fault) strainmeters on the Armutlu peninsula with a maximum amplitude of 5 microstrain and lasting about 50 days. The onset of the strain signal coincided with the origin time of a M W 4.4 earthquake offshore Yalova, which occurred as part of a seismic sequence including eight M W ≥3.5 earthquakes. The M W 4.4 event occurred at a distance of about 30 km from Esenkoy on June 25th 2016 representing the largest earthquake in this region since 2008. Before the event, the maximum horizontal strain was subparallel to the regional maximum horizontal stress derived from stress inversion of local seismicity. During the strain transient, we observe a clockwise rotation in the local horizontal strain field of about 20°. The strain signal does not correlate with known environmental parameters such as annual changes of sea level, rainfall or temperature. The strain signal could indicate local slow slip on the Cinarcik fault and thus a transfer of stress to the eastern Marmara seismic gap. © 2019 Elsevier B.V. Article 2019 English 0012821X 10.1016/j.epsl.2019.01.001 Earth and Planetary Science Letters 510 Elsevier B.V. 209 – 218 Armutlu Peninsula; Istanbul [Istanbul (PRV)]; Istanbul [Turkey]; Sea of Marmara; Turkey; Earthquakes; Offshore oil well production; Sea level; Strain measurement; Transform faults; Sea of Marmara; Seismic hazards; slow slip; Strain transients; Strain-meter; amplitude; earthquake event; earthquake rupture; fault slip; seismic hazard; strain; stress; transform fault; Fault slips https://www.scopus.com/inward/record.uri?eid=2-s2.0-85060524398&doi=10.1016%2fj.epsl.2019.01.001&partnerID=40&md5=d528516a0d81f96ff0d7739b323a8f52 Cited by: 12 Patricia Martínez-Garzón Marco Bohnhoff David Mencin Grzegorz Kwiatek Kathleen Hodgkinson Murat Nurlu Filiz Tuba Kadirioglu Recai Feyiz Kartal article Coianiz201915 The sedimentary sequences that accumulated within various lakes that occupied the Dead Sea Basin since the Pliocene, contain a detailed record of the climate and tectonic history of the area. Until recently, most of the information about these paleo-lakes was derived from exposures along the marginal terraces of the current Dead Sea (lake), focusing mainly on the last Glacial Lake Lisan and the Holocene-modern Dead Sea. The International Continental Drilling Program (ICDP) recovered a series of cores in the northern Dead Sea Basin, both in the deep depocenter (300 m water depth) and in shallower waters near the current shore. Here, we present downhole logging measurements that were used to provide continuous records of petrophysical properties at depth and to reconstruct lithological profiles. The study highlights how logging data can overcome gaps in drilled-core recovery and be used to examine subsurface geology on a regional scale. Gamma ray, resistivity and velocity wire logs were examined to infer a log-derived lithofacies. The reconstructed profiles presented in this study constitute a first attempt to link deep central settings of the basin with marginal sedimentary sequences. Three main facies were identified in the boreholes including: (Bartov et al., 2002) Finely laminated sequences of mudstones interbedded with siltstones to sandstones; (Bartov et al., 2003) Medium to thick bedded mudstone to sandstone: and (Bartov et al., 2007) Evaporites (e.g. halite and gypsum with some intervals of detrital sediments). The formations that were previously defined along the marginal terraces of the Dead Sea: the Holocene Ze'elim Formation, the last Glacial Lisan Formation, the last interglacial Samra Formation and the early to mid-Pleistocene Amora Formation are identified in the boreholes. A spatial correlation is established providing the stratigraphic architecture of the sedimentary structure beneath the Dead Sea during the late Quaternary. This paper combines geophysical and lithological data and provides the base for subsequent studies on facies interpretation. © 2018 Elsevier B.V. 2019 English 09269851 10.1016/j.jappgeo.2018.11.002 Journal of Applied Geophysics 160 Elsevier B.V. 15-27 Dr. Mosses Strauss Department of Marine Geosciences, Leon H. Charney School of Marine Sciences, University of Haifa, Mount Carmel, 3498838, Israel; Mediterranean Sea Research Centre of Israel (MERCI), University of Haifa, Haifa, 3498838, Israel; Department of Geophysics and Planetary Sciences, Tel-Aviv University, Ramat-Aviv, Tel-Aviv, 69978, Israel; Geological Survey of Israel, 30 Malkhe Israel Street, Jerusalem, 95501, Israel; The Institute of Earth Sciences, The Hebrew University of Jerusalem, Givat Ram, Jerusalem, 91904, Israel Boreholes; Boring; Gamma rays; Geophysics; Glacial geology; Infill drilling; Lakes; Lithology; Sandstone; Sodium chloride; Stratigraphy; Well logging, Dead sea basins; Downholes; Geophysical properties; ICDP; Petrophysical properties; Sedimentary structure; Stratigraphic architecture; Well logs, Sedimentology, facies analysis; lacustrine deposit; lithofacies; lithology; mudstone; Quaternary; reconstruction; sediment core; sedimentary sequence; sedimentary structure; siltstone; spatial analysis; temporal analysis; well logging, Dead Sea https://www.scopus.com/inward/record.uri?eid=2-s2.0-85056696395&doi=10.1016%2fj.jappgeo.2018.11.002&partnerID=40&md5=709de8675f700d925895f19d170a697a cited By 10 L. Coianiz Z. Ben-Avraham M. Stein M. Lazar conference Ogasawara201939 Conference paper 2019 10.1201/9780429327933-5 Rock Dynamics Summit - Proceedings of the 2019 Rock Dynamics Summit, RDS 2019 39 – 44 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85091657747&doi=10.1201%2f9780429327933-5&partnerID=40&md5=a3569cec87104380e609cfe6919ba7a0 Cited by: 0 H. Ogasawara A. Ishida K. Sugimura Y. Yabe S. Abe T. Ito A. Funato H. Kato B. Liebenberg G. Hofmann L. Scheepers R.J. Durrheim article Rae2019396 Deformation is a ubiquitous process that occurs to rocks during impact cratering; thus, quantifying the deformation of those rocks can provide first-order constraints on the process of impact cratering. Until now, specific quantification of the conditions of stress and strain within models of impact cratering has not been compared to structural observations. This paper describes a methodology to analyze stress and strain within numerical impact models. This method is then used to predict deformation and its cause during peak-ring formation: a complex process that is not fully understood, requiring remarkable transient weakening and causing a significant redistribution of crustal rocks. The presented results are timely due to the recent Joint International Ocean Discovery Program and International Continental Scientific Drilling Program drilling of the peak ring within the Chicxulub crater, permitting direct comparison between the deformation history within numerical models and the structural history of rocks from a peak ring. The modeled results are remarkably consistent with observed deformation within the Chicxulub peak ring, constraining the following: (1) the orientation of rocks relative to their preimpact orientation; (2) total strain, strain rates, and the type of shear during each stage of cratering; and (3) the orientation and magnitude of principal stresses during each stage of cratering. The methodology and analysis used to generate these predictions is general and, therefore, allows numerical impact models to be constrained by structural observations of impact craters and for those models to produce quantitative predictions. ©2019. American Geophysical Union. All Rights Reserved. 2019 10.1029/2018JE005821 Journal of Geophysical Research: Planets 124 396-417 Department of Earth Science and Engineering, Imperial College London, London, United Kingdom; Institut für Geo- und Umweltnaturwissenschaften, Albert-Ludwigs-Universität Freiburg, Geologie, Freiburg, Germany; Institut für Geologie, Universität Hamburg, Hamburg, Germany; Department of Earth Sciences/Centre for Planetary Science and Exploration, Western University, London, ON, Canada 2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85061564680&doi=10.1029%2f2018JE005821&partnerID=40&md5=66c0622c1c42f72ecffa147d91189719 cited By 25 A.S.P. Rae G.S. Collins M. Poelchau U. Riller T.M. Davison R.A.F. Grieve G.R. Osinski J.V. Morgan E. Iodp-Icdp article Fu20191052 During implementation of the Deep Continental Scientific Drilling Engineering Project Well SK-2 in Songliao Basin, the most integrated core data of Shahezi Formation was obtained. And 43 abnormal strata of deep shale gas were preliminarily identified, with a cumulative thickness of 102 meters, indicating that Shahezi Formation has good deep energy prospect. For further analysis of oil and gas resources potential of Shahezi Formation in Songliao basin, in this paper, on the basis of previous studies and in combination with well logging, core data of Well SK-2 and the newly acquired 2-d seismic data in the north-south direction crossing Well SK-2, the spatial distribution and sequence characteristics of Shahezi formation in the vicinity of Well SK-2 well were analyzed. At the same time, based on gas abnormal data acquired form logging during drilling, the authors studied logging and seismic responses of oil and gas perspective reservoirs in Shahezi Formation. It is shown that the Shahezi Formation adjacent to Well SK-2 has large thickness but small lateral extension, and hence the authors divided it into 4 stratigraphic sequences based on well logging as well as seismic and core data, i.e., SQ1, SQ2, SQ3 and SQ4. Among the 4 stratigraphic sequences, SQ4 has a better energy prospect. Its lithology is dominated by mudstone and has the characteristics of high porosity and low wave impedance on logging curves, with continuous strong amplitude on seismic section. Impedance inversion section shows the characteristics of large wave impedance alternated with many smaller wave impedances. Thus, the occurrence conditions of deep natural gas resources of Shahezi Formation in this area are revealed. © 2019 Editorial Board of Geology in China. All rights reserved. Article 2019 Chinese 10003657 10.12029/gc20190507 Geology in China 46 Science Press 1052 – 1060 5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85107642493&doi=10.12029%2fgc20190507&partnerID=40&md5=bcc115183da2b3ba582f825644560339 Cited by: 4 Wei Fu Hesheng Hou Jiaodong Zhang Cai Liu Xuan Feng Zhanwu Lu article Palchan2019395 The mineralogical, grain size and geochemical properties (e.g., Nd and Sr isotopes, Mg/Al ratios) of fine detritus that accumulated in the Dead Sea during the late Glacial to early Holocene time (∼22–7 ka) are used to identify its sources and modes of transport and to reconstruct the hydroclimate conditions in the Dead Sea watershed. Samples were retrieved from the DSDDP -5017-1A core that was drilled in the deep floor of the lake, and from various exposures of surface cover in the lake's watershed. The data show that during most of the late glacial, detrital particles were either directly blown mostly from the north Sahara Desert or were washed from the surface cover (loessial soils) of the north Negev Desert and Judea Desert. This picture changed during the end of the last glacial to the early Holocene (∼14 - 7 ka) when the fine detritus showed evidence for contribution from surface cover that contained basaltic soils. The contribution of basaltic soils to the fine detritus inventory of the Dead Sea and to terraces in the Jordan Valley, indicates a period of intense erosion in the northern highlands of the Dead Sea watershed, at an interval that partly coincides with Sapropel S1. In contrast, during the last interglacial Sapropel S5, fine detritus was mostly mobilized to the lake from southern and eastern region of the watershed. The formation and accumulation of terraces from this basaltic-derived material could be an important factor in the establishment of early agriculture settlements in the Jordan Valley. © 2019 Elsevier Ltd 2019 English 02773791 10.1016/j.quascirev.2019.05.028 Quaternary Science Reviews 218 Elsevier Ltd 395-405 Institute of Earth Sciences, The Hebrew University of Jerusalem, Givat Ram, Jerusalem, Israel; Geological Survey of Israel, 30 Malkhe Israel St., Jerusalem, Israel Basalt; Glacial geology; Lakes; Seawater; Soils; Watersheds, Basaltic soils; Dead sea basins; Derived materials; Early Holocene; Eastern regions; Geochemical properties; Jordan valley; Last interglacial, Landforms, basalt; detritus; fine grained sediment; grain size; Holocene; late glacial; mobilization; sapropel; seafloor; submarine terrace, Dead Sea; Israel; Jordan Valley; Negev; Sahara; Southern District https://www.scopus.com/inward/record.uri?eid=2-s2.0-85068875659&doi=10.1016%2fj.quascirev.2019.05.028&partnerID=40&md5=ed2cb6dbdbb78897820fb7db062e0cbb cited By 12 D. Palchan Y. Erel M. Stein article Martínez-Garzón2019 Quantifying regional earthquake cluster style is essential for providing a context for studies of seismicity patterns and earthquake interactions. Here, we identify clusters of seismicity in the Sea of Marmara region of the North Anatolian Fault, NW Turkey, using a recently derived high-resolution seismicity catalog and the nearest-neighbor earthquake cluster approach. The detected earthquake clusters are utilized for (1) determining spatial distribution of mainshock and aftershock rates and estimating the proximity to failure on different fault segments, (2) identifying fault sections having earthquake repeaters, and (3) finding areas with enhanced foreshock activity. About 6%, 70% and 24% of the events are identified as foreshocks, mainshocks and aftershocks, respectively, with the largest concentration of aftershocks and foreshocks located along the Western High and the Cinarcik Fault, respectively. The method successfully identifies regions where previous studies reported earthquake repeaters as indicator for fault creep and suggests additional repeater areas in the Gulf of Gemlik. The largest proportion of mainshocks with associated foreshocks and aftershocks are along the Western High and Cinarcik Fault segments, potentially indicating that these segments are closer to failure and have increased susceptibility to seismic triggering. Continuing studies can contribute to monitoring possible preparation phase of a large (M > 7) earthquake in the Marmara region near the Istanbul Metropolitan region. © 2019 Elsevier B.V. 2019 English 00401951 10.1016/j.tecto.2019.228176 Tectonophysics 768 Elsevier B.V. Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences, Section 4.2: Geomechanics and Scientific Drilling, Telegrafenberg, Potsdam, 14473, Germany; University of Southern California, Department of Earth Sciences, Los Angeles, CA 90089-0740, United States; University of Nevada, Reno, Department of Mathematics and Statistics, Reno, NV 89557, United States; Institute of Geological Sciences, Free University of Berlin, Berlin, Germany Faulting, Earthquake dynamics; Earthquake process; Fault segmentation; Metropolitan regions; North Anatolian Fault; Regional earthquakes; Seismicity clusters; Seismicity pattern, Earthquakes, aftershock; cluster analysis; earthquake catalogue; earthquake event; earthquake mechanism; earthquake trigger; fault; foreshock; North Anatolian Fault; seismicity, Gulf of Gemlik; Istanbul [Istanbul (PRV)]; Istanbul [Turkey]; Sea of Marmara; Turkey https://www.scopus.com/inward/record.uri?eid=2-s2.0-85070879394&doi=10.1016%2fj.tecto.2019.228176&partnerID=40&md5=b3ab7349182ee9562ef359ec2d3ad567 cited By 10 P. Martínez-Garzón Y. Ben-Zion I. Zaliapin M. Bohnhoff article Wagner2019256 Article 2019 10.1038/s41586-019-1529-0 Nature 573 256 – 260 7773 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85072099808&doi=10.1038%2fs41586-019-1529-0&partnerID=40&md5=ac9177f2941e1ddae1ad8fae224211d8 Cited by: 142; All Open Access, Green Open Access Bernd Wagner Hendrik Vogel Alexander Francke Tobias Friedrich Timme Donders Jack H. Lacey Melanie J. Leng Eleonora Regattieri Laura Sadori Thomas Wilke Giovanni Zanchetta Christian Albrecht Adele Bertini Nathalie Combourieu-Nebout Aleksandra Cvetkoska Biagio Giaccio Andon Grazhdani Torsten Hauffe Jens Holtvoeth Sebastien Joannin Elena Jovanovska Janna Just Katerina Kouli Ilias Kousis Andreas Koutsodendris Sebastian Krastel Markus Lagos Niklas Leicher Zlatko Levkov Katja Lindhorst Alessia Masi Martin Melles Anna M. Mercuri Sébastien Nomade Norbert Nowaczyk Konstantinos Panagiotopoulos Odile Peyron Jane M. Reed Leonardo Sagnotti Gaia Sinopoli Björn Stelbrink Roberto Sulpizio Axel Timmermann Slavica Tofilovska Paola Torri Friederike Wagner-Cremer Thomas Wonik Xiaosen Zhang article Deino2019 The Baringo-Tugen-Barsemoi 2013 drillcore (BTB13), acquired as part of the Hominin Sites and Paleolakes Drilling Project, recovered 228 m of fluviolacustrine sedimentary rocks and tuffs spanning a ~3.29–2.56 Ma interval of the highly fossiliferous and hominin-bearing Chemeron Formation, Tugen Hills, Kenya. Here we present a Bayesian stratigraphic age model for the core employing chronostratigraphic control points derived from 40Ar/39Ar dating of tuffs from core and outcrop, 40Ar/39Ar age calibration of related outcrop diatomaceous units, and core magnetostratigraphy. The age model reveals three main intervals with distinct sediment accumulation rates: an early rapid phase from 3.2 to 2.9 Ma; a relatively slow phase from 2.9 to 2.7 Ma; and the highest rate of accumulation from 2.7 to 2.6 Ma. The intervals of rapid accumulation correspond to periods of high Earth orbital eccentricity, whereas the slow accumulation interval corresponds to low eccentricity at 2.9–2.7 Ma, suggesting that astronomically mediated climate processes may be responsible for the observed changes in sediment accumulation rate. Lacustrine transgression-regression events, as delineated using sequence stratigraphy, dominantly operate on precession scale, particularly within the high eccentricity periods. A set of erosively based fluvial conglomerates correspond to the 2.9–2.7 Ma interval, which could be related to either the depositional response to low eccentricity or to the development of unconformities due to local tectonic activity. Age calibration of core magnetic susceptibility and gamma density logs indicates a close temporal correspondence between a shift from high- to low-frequency signal variability at ~3 Ma, approximately coincident the end of the mid-Piacenzian Warm Period, and the beginning of the cooling of world climate leading to the initiation of Northern Hemispheric glaciation c. 2.7 Ma. BTB13 and the Baringo Basin records may thus provide evidence of a connection between high-latitude glaciation and equatorial terrestrial climate toward the end of the Pliocene. © 2019 Elsevier B.V. Article 2019 English 00310182 10.1016/j.palaeo.2019.109258 Palaeogeography, Palaeoclimatology, Palaeoecology 532 Elsevier B.V. accumulation rate; age determination; Bayesian analysis; chronostratigraphy; core logging; dating method; eccentricity; magnetostratigraphy; modeling; outcrop; paleoclimate; paleolimnology; Pliocene; precession; sequence stratigraphy; tephrochronology https://www.scopus.com/inward/record.uri?eid=2-s2.0-85069751249&doi=10.1016%2fj.palaeo.2019.109258&partnerID=40&md5=43dc8b54e738a22fe5f16c08c909c0d0 Cited by: 2; All Open Access, Green Open Access A.L. Deino M.J. Sier D. Garello B. Keller J. Kingston J. Scott G. Dupont-Nivet A. Cohen article Leicher2019 Article 2019 10.1016/j.quascirev.2019.106021 Quaternary Science Reviews 226 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85074263615&doi=10.1016%2fj.quascirev.2019.106021&partnerID=40&md5=06d43a5dc41c0acd23c1d271620bff2a Cited by: 30 Niklas Leicher Biagio Giaccio Giovanni Zanchetta Bernd Wagner Alexander Francke Danilo M. Palladino Roberto Sulpizio Paul G. Albert Emma L. Tomlinson article ZhengYuejuan 2019 1000-3657 10.12029/gc20190527 Geology in China 46 1245-1246 5 /article/id/5fdc5ee1ed73f80a08606525 Zheng Yuejuan Chen Shuwang Zhang Dejun Huang Xin article Sheppard201911 Sediments collected from Lake Towuti, an ultramafic-hosted lake in Indonesia, preserve a visible alternating pattern of red and green sediments due to variations in clay mineral and Fe-oxide composition and abundance consistent with changes in iron oxidation state through time. Spectral, mineralogical, and chemical analyses on soils, river, and sediment samples from across the lake and its catchment were carried out to better understand the starting composition of these sediments and the processes that affected them before and after deposition. Despite high Fe abundances in all samples and abundant Fe oxides in lateritic source regions, mineralogical analyses (X-ray diffraction (XRD) and Mössbauer spectroscopy) of the modern lake sediment show almost no well-crystalline iron oxides. In addition, sequential Fe extractions suggest an increasing proportion of easily extractable, poorly crystalline (X-ray amorphous) material with burial depth. XRD, bulk chemistry, and visible-near infrared (VNIR) spectral reflectance measurements demonstrate that clay mineralogy and bulk chemistry can be inferred from VNIR data. These results provide evidence for variations in Fe mineralogy and crystallinity based on location in this source to sink system. Understanding how the mineralogy and chemistry of sediments within a ferruginous lake basin are affected by transport, chemical alteration, physical alteration, and deposition from source to sink on Earth, and the degree to which these trends and underlying processes can be inferred from chemical and spectral properties, may provide useful direction in assessing paleoenvironmental conditions in other terrestrial lakes as well as ancient lacustrine environments preserved in the stratigraphic record of Mars. © 2019 Elsevier B.V. Article 2019 English 00092541 10.1016/j.chemgeo.2019.02.029 Chemical Geology 512 Elsevier B.V. 11 – 30 Greater Sunda Islands; Lake Towuti; Malili Lakes; South Sulawesi; Sulawesi; Sunda Isles; Catchments; Chemical analysis; Clay minerals; Crystalline materials; Crystallinity; Deposition; Infrared devices; Lakes; Sedimentation; Sediments; Stratigraphy; X ray diffraction; Fe oxide; Mars analogue; Mineralogical analysis; Modern lake sediments; Spectral reflectance measurements; Ssbauer spectroscopies; Stratified lakes; Stratigraphic records; iron oxide; lacustrine deposit; Mars; paleoenvironment; redox conditions; sediment analysis; sediment chemistry; sedimentation; X-ray diffraction; Iron oxides https://www.scopus.com/inward/record.uri?eid=2-s2.0-85062414349&doi=10.1016%2fj.chemgeo.2019.02.029&partnerID=40&md5=6691785ad26224a94f0ade0ccac63ee5 Cited by: 10; All Open Access, Bronze Open Access Rachel Y. Sheppard Ralph E. Milliken James M. Russell M. Darby Dyar Elizabeth C. Sklute Satria Bijaksana Marina A. Morlock Ascelina K.M. Hasberg article Li201947 Charophyte assemblages from the mid-Campanian and lower Paleocene of the SK-1(North) borehole in the Songliao Basin (NE China) are here re-studied. Four charophyte biozones and one superzone are defined in the Sifangtai and Mingshui formations and correlated to the Geomagnetic Polarity Time Scale. These include a mid–late Campanian Atopochara trivolvis ulanensis Zone, a latest Campanian – early Maastrichtian Microchara gobica Zone, a late Maastrichtian Microchara prolixa Zone, and an earliest Danian Peckichara sinuolata Zone. The latter three zones are grouped within the Microchara cristata Superzone, which allows intra- and intercontinental correlation with other basins in China and Europe. Peckichara sinuolata first appears in chron C29r (upper Mingshui Formation) and is proposed as the basal marker of the Paleocene. The biozonation of the K/Pg interval proposed for the Songliao Basin differs from a previous biozonation proposed in the Pingyi Basin since it represents a different biogeographical and palaeoecological context. In the mid-Campanian to Maastrichtian, the flora was limited to freshwater lakes in northern China and Mongolia, whereas in the Pingyi Basin, brackish water dominated. In the Paleocene, the Songliao Basin contained a diverse flora consisting of nine species that thrived in terrigenous and temporary lakes, whereas the flora in the Pingyi Basin was dominated by one species inhabiting permanent alkaline lakes. The species common to the two basins are widely distributed in Eurasia and constitute a useful tool for long-distance correlations, but serve as a less-precise tool for detailed biostratigraphical subdivision within one specific basin. © The Palaeontological Association 2019 English 20562802 10.1002/spp2.1225 Papers in Palaeontology 5 Wiley-Blackwell Publishing Ltd 47-81 CAS Key Laboratory of Economic Stratigraphy & Palaeogeography, Nanjing Institute of Geology & Palaeontology, Centre for Excellence in Life & Paleoenvironment, Chinese Academy of Sciences, 39 East Beijing Road, Nanjing, 210008, China; Nanjing Institute of Geology & Palaeontology, Centre for Excellence in Life & Paleoenvironment, Chinese Academy of Sciences, 39 East Beijing Road, Nanjing, 210008, China; State Key Laboratory of Palaeobiology & Stratigraphy, Nanjing Institute of Geology & Palaeontology, Center for Excellence in Life & Paleoenvironment, Chinese Academy of Sciences, 39 East Beijing Road, Nanjing, 210008, China; State Key Laboratory of Biogeology & Environmental Geology, China University of Geosciences, Beijing, 100083, China; Departament de Dinàmica de la Terra i de l'Oceà, Facultat de Ciències de la Terra, Universitat de Barcelona, Barcelona, Catalonia 08028, Spain 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85051059740&doi=10.1002%2fspp2.1225&partnerID=40&md5=6cbcc0f522e80100553e8f002bda2fae cited By 18 S. Li Q. Wang X. Wan C. Martín-Closas article Podugu2019 A 3 km deep research borehole KFD1 was drilled in the Koyna reservoir-triggered seismicity region, Western India, between December 2016 and May 2017. The 1967 M 6.3 Koyna earthquake had generated a NNE-SSW trending surface fissure zone in the Nanel-Donichawadi-Kadoli sector. KFD1 is located 5 km south of Kadoli along the trend of the Donichawadi fault zone. Online gas monitoring was carried out during drilling of KFD1 from 1315 m to 2831 m depth to sample and study the composition of crustal gases. Formation gases CO2, CH4, H2, and He were only observed during water flushing of 100 m intervals following coring runs. Laboratory analyses of gas samples collected between 1737 m and 2831 m depth revealed concentrations of up to 1200 ppmv CO2, 186 ppmv CH4, 139 ppmv H2, and 12.8 ppmv He. Zones enriched in gases are mostly below the 2100 m depth with significant He enhancement ranging from 4.6 to 7.6 ppmv above the atmospheric value. The He-rich zones correlate well with the zones of anomalous physical and mechanical properties identified from geophysical logs and are characterized by high fracture density as revealed from borehole images, indicating that the borehole punctured multiple fracture zones. The helium concentrations are consistent with those previously observed over the surface fissures near Kadoli, suggesting a southward extension of the Donichawadi fault zone up to the KFD1 site and confirming that the fault zone is permeable even after 50 years of the 1967 Koyna earthquake.3He/4He ratios of eleven gas samples fall between 0.426±0.022 and 0.912±0.059 Ra, with 4He/20Ne values between 0.3449±0.0091 and 0.751±0.020. Air-corrected helium isotope ratios indicate that helium is a mixture of atmospheric and crustal radiogenic components but no mantle contribution within 2σ analytical uncertainties. © 2019 Nagaraju Podugu et al. 2019 English 14688115 10.1155/2019/1078942 Geofluids 2019 Hindawi Limited Ministry of Earth Sciences, Borehole Geophysics Research Laboratory, Karad, 415 114, India; GFZ German Research Centre for Geosciences, Telegrafenberg, Potsdam, 14473, Germany borehole; carbon dioxide; concentration (composition); drilling; earthquake magnitude; earthquake mechanism; enrichment; fracture zone; gas flow; helium; isotopic composition; isotopic ratio; methane; noble gas; research; reservoir-induced seismicity; source rock, India; Koyna; Maharashtra https://www.scopus.com/inward/record.uri?eid=2-s2.0-85072962263&doi=10.1155%2f2019%2f1078942&partnerID=40&md5=f03e1e9f504d7042f22ccc870fc11e56 cited By 10 N. Podugu S. Mishra T. Wiersberg S. Roy article Deino2019213 The Olorgesailie Drilling Project and the related Hominin Sites and Paleolakes Drilling Project in East Africa were initiated to test hypotheses and models linking environmental change to hominin evolution by drilling lake basin sediments adjacent to important archeological and paleoanthropological sites. Drill core OLO12-1A recovered 139 m of sedimentary and volcaniclastic strata from the Koora paleolake basin, southern Kenya Rift, providing the opportunity to compare paleoenvironmental influences over the past million years with the parallel record exposed at the nearby Olorgesailie archeological site. To refine our ability to link core-to-outcrop paleoenvironmental records, we institute here a methodological framework for deriving a robust age model for the complex lithostratigraphy of OLO12-1A. Firstly, chronostratigraphic control points for the core were established based on 40Ar/39Ar ages from intercalated tephra deposits and a basal trachyte flow, as well as the stratigraphic position of the Brunhes-Matuyama geomagnetic reversal. This dataset was combined with the position and duration of paleosols, and analyzed using a new Bayesian algorithm for high-resolution age-depth modeling of hiatus-bearing stratigraphic sections. This model addresses three important aspects relevant to highly dynamic, non-linear depositional environments: 1)correcting for variable rates of deposition, 2)accommodating hiatuses, and 3)quantifying realistic age uncertainty with centimetric resolution. Our method is applicable to typical depositional systems in extensional rifts as well as to drill cores from other dynamic terrestrial or aquatic environments. We use the core age model and lithostratigraphy to examine the interconnectivity of the Koora Basin to adjacent areas and sources of volcanism. © 2019 Elsevier Ltd Article 2019 English 02773791 10.1016/j.quascirev.2019.05.009 Quaternary Science Reviews 215 Elsevier Ltd 213 – 231 East Africa; East African Rift; Kenya; Kenya Rift; Bayesian networks; Deposition; Drills; Geologic models; Geomagnetism; Infill drilling; Paleolimnology; Sedimentology; Stratigraphy; Bayesian model; East Africa; Kenya rift; Magnetostratigraphy; paleosol; Pleistocene; Radiogenic isotopes; Tephrostratigraphy; algorithm; archaeology; Bayesian analysis; chronostratigraphy; depositional environment; drill bit; drilling; environmental change; extensional tectonics; historical record; hominid; human evolution; hypothesis testing; isotopic analysis; lacustrine deposit; lithostratigraphy; magnetic reversal; magnetostratigraphy; numerical model; paleoenvironment; paleohydrology; paleolimnology; paleosol; Pleistocene; sedimentation rate; sedimentology; tectonostratigraphy; volcaniclastic deposit; volcanism; Core drilling https://www.scopus.com/inward/record.uri?eid=2-s2.0-85067949023&doi=10.1016%2fj.quascirev.2019.05.009&partnerID=40&md5=ad5f646719139ccc871604d2949efd16 Cited by: 12; All Open Access, Bronze Open Access A.L. Deino R. Dommain C.B. Keller R. Potts A.K. Behrensmeyer E.J. Beverly J. King C.W. Heil M. Stockhecke E.T. Brown J. Moerman P. deMenocal inproceedings 1952_28_Ogasawara In 2014, a M5.5 earthquake ruptured the range of depths between 3.5 km and 7 km near Orkney, South Africa. The main and aftershocks were very well monitored in the nearfield by dense, surface, strong motion meters and a dense underground seismic network in the deep gold mines. The mechanism of this M5.5 earthquake was left-lateral strike-slip faulting, differing from typical mining-induced earthquakes with normal-faulting mechanisms on the mining horizons shallower than 3.5 km depth. To understand why such an unusual event took place, the aftershock zone was probed by full-core NQ drilling during 2017-2018, with a total length of about 1.6 km, followed by in-hole geophysical logging, core logging, core testing, and monitoring in the drilled holes. These holes also presented a rare opportunity to investigate deep life. In addition, seismogenic zones of M2–M3 earthquakes were probed on mine horizons that were also very well monitored by acoustic emission networks. This paper reviews the early results of the project. 2019 10.36487/ACG_rep/1952_28_Ogasawara Deep Mining 2019: Proceedings of the Ninth International Conference on Deep and High Stress Mining The Southern African Institute of Mining and Metallurgy Joughin W 375-384 https://papers.acg.uwa.edu.au/p/1952_28_Ogasawara/ H Ogasawara B Liebenberg M Rickenbacher M Ziegler H Esterhuizen TC Onstott MSD Durrheim S Mngadi Y Yabe S Kaneki E Cason J-G Vermeuren E Heerden T Wiersberg M Zimmer C Kujawa R Conze G Aswegen N Wechsler AK Ward S Enslin S Tau MS Bucibo article Pieńkowski2019449 Article 2019 10.7306/gq.1480 Geological Quarterly 63 449 – 459 3 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85075082891&doi=10.7306%2fgq.1480&partnerID=40&md5=b545a068672f5f95c106af7373a08b31 Cited by: 1; All Open Access, Gold Open Access Grzegorz Pieńkowski Michelangelo Martini Mildred Zepeda-Martínez article Trauth20192557 The Chew Bahir Drilling Project (CBDP) aims to test possible linkages between climate and evolution in Africa through the analysis of sediment cores that have recorded environmental changes in the Chew Bahir basin. In this statistical project we consider the Chew Bahir palaeolake to be a dynamical system consisting of interactions between its different components, such as the waterbody, the sediment beneath lake, and the organisms living within and around the lake. Recurrence is a common feature of such dynamical systems, with recurring patterns in the state of the system reflecting typical influences. Identifying and defining these influences contributes significantly to our understanding of the dynamics of the system. Different recurring changes in precipitation, evaporation, and wind speed in the Chew Bahir basin could result in similar (but not identical) conditions in the lake (e.g., depth and area of the lake, alkalinity and salinity of the lake water, species assemblages in the water body, and diagenesis in the sediments). Recurrence plots (RPs) are graphic displays of such recurring states within a system. Measures of complexity were subsequently introduced to complement the visual inspection of recurrence plots, and provide quantitative descriptions for use in recurrence quantification analysis (RQA). We present and discuss herein results from an RQA on the environmental record from six short (< 17 m) sediment cores collected during the CBDP, spanning the last 45 kyrs. The different types of variability and transitions in these records were classified to improve our understanding of the response of the biosphere to climate change, and especially the response of humans in the area. © 2019, Springer-Verlag GmbH Germany, part of Springer Nature. 2019 English 09307575 10.1007/s00382-019-04641-3 Climate Dynamics 53 Springer Verlag 2557-2572 Institute of Geosciences, University of Potsdam, Potsdam, Germany; School of Earth Sciences, Addis Ababa University, Addis Ababa, Ethiopia; Institute of Geography Education, University of Cologne, Cologne, Germany; Potsdam Institute for Climate Impact Research, Potsdam, Germany; Department of Geography, University College London, London, United Kingdom 5-6 atmospheric dynamics; climate change; Holocene; paleoclimate; Pleistocene; recurrence interval; time series analysis, Ethiopia https://www.scopus.com/inward/record.uri?eid=2-s2.0-85061043150&doi=10.1007%2fs00382-019-04641-3&partnerID=40&md5=f17f6c2728b3d929241dea35682f57cd cited By 23 M.H. Trauth A. Asrat W. Duesing V. Foerster K.H. Kraemer N. Marwan M.A. Maslin F. Schaebitz article Deconinck20192769 Article 2019 10.1111/sed.12610 Sedimentology 66 2769 – 2783 7 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85067349190&doi=10.1111%2fsed.12610&partnerID=40&md5=5d47b6ff4dac8df4ac2ef79c8c0f258e Cited by: 42; All Open Access, Green Open Access, Hybrid Gold Open Access Jean-François Deconinck Stephen P. Hesselbo Pierre Pellenard article Morlock2019279 Humid tropical landscapes are subject to intense weathering and erosion, which strongly influence sediment mobilisation and deposition. In this setting, we aimed to understand how geomorphology and hydroclimate altered the style and intensity of erosion and sediment composition in a tropical lake and its tectonically active catchment. Lake Towuti (2.75°S, 121.5°E) is one of the oldest and deepest lakes in Indonesia, with uninterrupted lacustrine sedimentation over several glacial–interglacial cycles. Here we present results from a novel set of Lake Towuti surface sediment, bedrock and soil samples from the catchment, and two existing sediment cores that extend to 30,000 and 60,000 years before present. We studied the catchment morphology, soil properties, geochemistry, and clay and bulk mineralogy. Results from several river long profiles show clear signs of tectonic activity, which enhances river incision, favours mass movement processes, and together with remobilisation of fluvial deposits, strongly influences modern sedimentation in the lake. Material from the Mahalona River, the lake’s largest inflow, dominates modern sediment composition in Towuti’s northern basin. The river transports Al-poor and Mg-rich sediments (mainly serpentines) to the lake, indicating river incision into the Mg-rich serpentinised peridotite bedrock. Relatively small, but important additional contributions of material, come from direct laterite-derived input and the Loeha River, which both provide Al-rich and Mg-poor sediment to the lake. Over time, the Al/Mg and kaolinite-to-serpentine ratios varied strongly, primarily in response to lake-level fluctuations driven by hydroclimatic changes. In the past 60,000 years, both the Al/Mg and kaolinite-to-serpentine ratios showed variations sensitive to changes in climate boundary conditions across glacial-interglacial cycles, while tectonic activity had less influence on changes in sediment composition on these short time-scales. © 2018, Springer Nature B.V. Article 2019 English 09212728 10.1007/s10933-018-0059-3 Journal of Paleolimnology 61 Springer Netherlands 279 – 295 3 Greater Sunda Islands; Lake Towuti; Malili Lakes; South Sulawesi; Sulawesi; Sunda Isles; bank erosion; bedrock; catchment; climate effect; geomorphology; hydrological regime; lacustrine deposit; lake level; paleoclimate; peridotite; sedimentation rate; source-sink dynamics; tectonic setting; tropical region; weathering rate https://www.scopus.com/inward/record.uri?eid=2-s2.0-85055054448&doi=10.1007%2fs10933-018-0059-3&partnerID=40&md5=14b79789fe5aaf9e2b5b6c13f68b006b Cited by: 10; All Open Access, Green Open Access Marina A. Morlock Valentin Nigg Luis Ordoñez Ascelina K. M. Hasberg James M. Russell Satria Bijaksana article Belmaker2019 The laminated sequences of the Holocene Dead Sea (DS) and its late Pleistocene precursor Lake Lisan comprise primary aragonite and fine detritus that record the hydro-climate conditions of the late Quaternary Levant. Several studies suggested that the primary aragonite precipitated due to mixing between runoff that brought bicarbonate to the lake and the lake's Ca-chloride brine. However, the factors controlling the aragonite precipitation were not robustly established. Here, we addressed this issue by measuring the chemical composition (pH, Na+, K+, Ca2+, Mg2+, Sr2+, Cl−, Br−, B, alkalinity) of flood plumes where the mixing occurs. The results indicate that: (a) Na+, Mg2+, K+ and Cl− are conservative during the floodwater-brine mixing whereas Ca2+ and Sr2+ adsorb on flood's suspended sediments; (b) Boron (an important alkalinity species in the DS) adsorption on flood's suspended load enabled the bicarbonate that entered the lake via runoff to react with the Ca2+ thus facilitating aragonite precipitation (c) Dissolution of calcite dust blown from the Sahara during winter storm is the source of bicarbonate which is required for aragonite precipitation. These observations explain the occurrence of aragonite laminae both during the wet last glacial period and during the dry last 3000yr. Although the water input during these two periods was completely different, they both were characterized by high dust fluxes and a stratified lake configuration in which the boron concentrations in the epilimnion were low enough to enable the bicarbonate that entered the lake via runoff to react with the lake brine Ca2+ and precipitate aragonite. © 2019 Elsevier Ltd 2019 English 02773791 10.1016/j.quascirev.2019.105876 Quaternary Science Reviews 221 Elsevier Ltd Dr. Strauss Department of Marine Geosciences, Charney School of Marine Sciences, University of Haifa, Mount Carmel, Haifa, Israel; The Fredy & Nadine Hermann Institute of Earth Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel; Geological Survey of Israel, 32 Yesha'ayahu Leibowitz St., Jerusalem, 9692100, Israel Alkalinity; Boron; Brines; Calcite; Chlorine compounds; Dust; Floods; Lakes; Mixing; pH; Runoff; Storms; Suspended sediments, Boron concentrations; Carbonate alkalinity; Chemical compositions; Dead sea; Flood plumes; Geochemical measurements; Last glacial period; Primary aragonite, Carbonate minerals, alkalinity; aragonite; borate; brine; carbonate; chemical composition; climate conditions; dissolution; dust; epilimnion; flood; geochemistry; Holocene; hydrometeorology; measurement method; Pleistocene; precipitation (chemistry), Dead Sea https://www.scopus.com/inward/record.uri?eid=2-s2.0-85070567363&doi=10.1016%2fj.quascirev.2019.105876&partnerID=40&md5=5711d744139c5f8d996a0c56a11b443f cited By 19 R. Belmaker B. Lazar M. Stein N. Taha R. Bookman article Yang2019212 In situ stress measurement at seismogenic depth is critically important for deciphering fault zone processes. In this study, we conducted a second active-source crosswell field experiment at the Parkfield San Andreas Fault Observatory at Depth (SAFOD) drill site to investigate the detectability of stress-induced seismic velocity changes at the top part of the seismogenic zone. We employed the same configuration of our previous experiments, which deployed a piezoelectric source and a three-component (3C) accelerometer at 1 km deep inside the pilot and main holes, respectively. We also added a hydrophone, which is attached to the source, to monitor the repeatability of the source waveforms. Over a 40-day recording period, we confirmed an ∼0:04% travel-time variation in S wave and coda that roughly follows the fluctuation of barometric pressure. We attributed this correlation to stress sensitivity of seismic velocity and the stress sensitivity is estimated to be 2:0 × 10 −7 Pa −1 , which is approximately two orders of magnitude higher than those measured in laboratory with dry rock samples, but is consistent with our previous results. Our results confirm the hypothesis that substantial cracks and/or pore spaces exist at seismogenic depths and thus may be used to monitor the subsurface stress field with active-source crosswell seismic. © 2019 Seismological Society of America. All Rights Reserved. 2019 English 08950695 10.1785/0220180080 Seismological Research Letters 90 Seismological Society of America 212-218 Department of Earth, Environmental, and Planetary Sciences, Rice University, 6100 Main Street, Houston, TX 77005, United States; Earth Science Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, United States; Berkeley Seismological Laboratory, University of California, 219 McCone Hall, Berkeley, CA 94720, United States 1 Atmospheric pressure; Seismic waves; Seismology; Shear waves; Stresses; Strike-slip faults, Barometric pressure; Continuous measurements; In-situ stress measurement; Orders of magnitude; San Andreas fault; Seismic velocities; Stress sensitivity; Sub-surface stress field, Traffic control, fault zone; in situ measurement; in situ stress; San Andreas Fault; seismic velocity; seismic zone; seismology; travel time; waveform analysis, California; Parkfield; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-85062921101&doi=10.1785%2f0220180080&partnerID=40&md5=697d56a43548215184f4470c4e6c9023 cited By 2 C. Yang F. Niu T.M. Daley T. Taira article Zoccatelli20192665 Article 2019 10.5194/hess-23-2665-2019 Hydrology and Earth System Sciences 23 2665 – 2678 6 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85067873341&doi=10.5194%2fhess-23-2665-2019&partnerID=40&md5=29b9192f2f7c168940a2e13b94727ace Cited by: 33; All Open Access, Gold Open Access, Green Open Access Davide Zoccatelli Francesco Marra Moshe Armon Yair Rinat James A. Smith Efrat Morin article Qin2024168 Article 2019 10.3969/j.issn.2095-1132.2019.01.008 Natural Gas Technology and Economy 13 34-38+82 01 X. Liu H. Wu X. Yan Y. Li article Jackson20193751 Micrometer-scale maps of authigenic microstructures in submarine basaltic tuff from a 1979 Surtsey volcano, Iceland, drill core acquired 15 years after eruptions terminated describe the initial alteration of oceanic basalt in a low-temperature hydrothermal system. An integrative investigative approach uses synchrotron source X-ray microdiffraction, microfluoresence, micro-computed tomography, and scanning transmission electron microscopy coupled with Raman spectroscopy to create finely resolved spatial frameworks that record a continuum of alteration in glass and olivine. Microanalytical maps of vesicular and fractured lapilli in specimens from 157.1-, 137.9-, and 102.6-m depths and borehole temperatures of 83, 93.9, and 141.3 °C measured in 1980, respectively, describe the production of nanocrystalline clay mineral, zeolites, and Al-tobermorite in diverse microenvironments. Irregular alteration fronts at 157.1-m depth resemble microchannels associated with biological activity in older basalts. By contrast, linear microstructures with little resemblance to previously described alteration features have nanocrystalline clay mineral (nontronite) and zeolite (amicite) texture. The crystallographic preferred orientation rotates around an axis parallel to the linear feature. Raman spectra indicating degraded and poorly ordered carbonaceous matter of possible biological origin are associated with nanocrystalline clay mineral in a crystallographically oriented linear microstructure in altered olivine at 102.6 m and with subcircular nanoscale cavities in altered glass at 137.9-m depth. Although evidence for biotic processes is inconclusive, the integrated analyses describe the complex organization of previously unrecognized mineral texture in very young basalt. They provide a foundational mineralogical reference for longitudinal, time-lapse characterizations of palagonitized basalt in oceanic environments. ©2019. American Geophysical Union. All Rights Reserved. 2019 English 15252027 10.1029/2019GC008304 Geochemistry, Geophysics, Geosystems 20 Blackwell Publishing Ltd 3751-3773 Department of Geology and Geophysics, University of Utah, Salt Lake City, UT, United States; NIF and Photon Science, Livermore National Laboratory, Livermore, CA, United States; Department of Biology and Nordic Center for Earth Evolution, University of Southern Denmark, Odense, Denmark; Department of Palaeobiology, Swedish Museum of Natural History, Stockholm, Sweden; Department of Mechanical Engineering, University of Utah, Salt Lake City, UT, United States; Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, United States; U.S. Geological Survey, Menlo Park, CA, United States 7 Basalt; Bioactivity; Clay alteration; Clay minerals; Computerized tomography; Drills; Glass; High resolution transmission electron microscopy; Infill drilling; Micrometers; Nanocrystals; Olivine; Photodegradation; Raman spectroscopy; Scanning electron microscopy; Submarines; Temperature; Textures; Volcanoes; X ray diffraction; X rays; Zeolites, Borehole temperature; Crystallographic preferred orientations; Glass alteration; Microcomputed tomography; Micrometer scale; Scanning transmission electron microscopy; Submarine basalt; X ray microdiffraction, Core drilling, basalt; glass; hydrothermal alteration; hydrothermal system; mineral deposit; Raman spectroscopy; tuff; underwater environment; X-ray diffraction, Iceland; Surtsey https://www.scopus.com/inward/record.uri?eid=2-s2.0-85070113178&doi=10.1029%2f2019GC008304&partnerID=40&md5=f16db305b98af20ed8b3d4ed54dd66d3 cited By 8 M.D. Jackson S. Couper C.V. Stan M. Ivarsson M.W. Czabaj N. Tamura D. Parkinson L.M. Miyagi J.G. Moore techreport guglielmi_crystalline_2019 2019 en Lawrence Berkeley National Laboratory (LBNL)

Berkeley

47 Yves Guglielmi Paul Cook Patrick Dobson Seiji Nakagawa Liange Zheng Auli Niemi Chris Juhlin Henning Lorenz Jan-Erik Rosberg Benoît Dessirier Chin-Fu Tsang Alexandru Tatomir Farzad Basirat Emil Lundberg Bjarne Almqvist Sharon Borglin Chris Doughty article Miebach201998 The southern Levant is a key region for studying vegetation developments in relation to climate dynamics and hominin migration processes in the past due to the sensitivity of the vegetation to climate variations and the long history of different anthropogenic occupation phases. However, paleoenvironmental conditions in the southern Levant during the Late Pleistocene were still insufficiently understood. Therefore, we investigated the vegetation and fire history of the Dead Sea region during the last glacial period. We present a new palynological study conducted on sediments of Lake Lisan, the last glacial precursor of the Dead Sea. The sediments were recovered from the center of the modern Dead Sea within an ICDP campaign. The palynological results suggest that Irano-Turanian steppe and Saharo-Arabian desert vegetation prevailed in the Dead Sea region during the investigated period (ca. 88,000–14,000 years BP). Nevertheless, Mediterranean woodland elements significantly contributed to the vegetation composition, suggesting moderate amounts of available water for plants. The early last glacial was characterized by dynamic climate conditions with pronounced dry phases and high but unstable fire activity. Anatomically modern humans entered the southern Levant during a climatically stable phase (late MIS 4–MIS 3)with diverse habitats, constant moisture availability, and low fire activity. MIS 2 was the coldest phase of the investigated timeframe, causing changes in woodland composition and a widespread occurrence of steppe. We used a biome modeling approach to assess regional vegetation patterns under changing climate conditions and to evaluate different climate scenarios for the last glacial Levant. The study provides new insights into the environmental responses of the Dead Sea region to climate variations through time. It contributes towards our understanding of the paleoenvironmental conditions in the southern Levant, which functioned as an important corridor for human migration processes. © 2019 Elsevier Ltd 2019 English 02773791 10.1016/j.quascirev.2019.04.033 Quaternary Science Reviews 214 Elsevier Ltd 98-116 Institute of Geosciences and Meteorology, Section Palaeontology, University of Bonn, Nussallee 8, Bonn, 53115, Germany; Institute of Geodesy and Geoinformation, University of Bonn, Nussallee 17, Bonn, 53115, Germany; Institute of Geosciences and Meteorology, Section Meteorology, University of Bonn, Auf dem Hügel 20, Bonn, 53121, Germany Charcoal; Fires; Glacial geology; Lakes; Sensitivity analysis, Anatomically modern humans; Deep drilling; Eastern Mediterranean; Fire history; Late Pleistocene; Paleoclimates; Vegetation dynamics, Vegetation, anatomy; biome; charcoal; ecological modeling; fire history; hominid; Last Glacial; marine isotope stage; paleoclimate; paleoenvironment; palynology; vegetation dynamics, Dead Sea; Levant; Mediterranean Region https://www.scopus.com/inward/record.uri?eid=2-s2.0-85065576356&doi=10.1016%2fj.quascirev.2019.04.033&partnerID=40&md5=c36c0d1abab20acd378a285eaa14c69e cited By 24 A. Miebach S. Stolzenberger L. Wacker A. Hense T. Litt article Kushnir2019 This paper examines the hydroclimate history of the Eastern Mediterranean (EM) region during the 10th to 14th centuries C.E., a period known as the Medieval Climate Anomaly (MCA), a time of significant historical turmoil and change in the region. The study assembles several regional hydroclimatic archives, primarily the Dead Sea reconstructed lake level curve together with the recently extracted deep-lake sediment record, the Soreq Cave speleothem record and its counterpart, the EM marine sediment record and the Cairo Nilometer record of annual maximum summer flood levels in lower Egypt. The Dead Sea record is a primary indicator of the intensity of the EM cold-season storm activity while the Nilometer reflects the intensity of the late summer monsoon rains over Ethiopia. These two climate systems control the annual rainfall amounts and water availability in the two regional breadbaskets of old, in Mesopotamia and Egypt. The paleoclimate archives portray a variable MCA in both the Levant and the Ethiopian Highlands with an overall dry, early-medieval climate that turned wetter in the 12th century C.E. However, the paleoclimatic records are markedly punctuated by episodes of extreme aridity. In particular, the Dead Sea displays extreme low lake levels and significant salt deposits starting as early as the 9th century C.E. and ending in the late 11th century. The Nile summer flood levels were particularly low during the 10th and 11th centuries, as is also recorded in a large number of historical chronicles that described a large cluster of droughts that led to dire human strife associated with famine, pestilence and conflict. During that time droughts and cold spells also affected the northeastern Middle East, in Persia and Mesopotamia. Seeking an explanation for the pronounced aridity and human consequences across the entire EM, we note that the 10th-11th century events coincide with the medieval Oort Grand Solar Minimum, which came at the height of an interval of relatively high solar irradiance. Bringing together other tropical and Northern Hemisphere paleoclimatic evidence, we argue for the role of long-term variations in solar irradiance in shaping the early MCA in the EM and highlight their relevance to the present and near-term future. © 2019 by the authors. 2019 English 20734433 10.3390/atmos10010029 Atmosphere 10 MDPI AG Lamont-Doherty Earth Observatory, Columbia University, 61 Route 9W, Palisades, NY 10964, United States; Institute of Earth Sciences, The Hebrew University of Jerusalem, Givat Ram, Jerusalem, Israel; Geological Survey of Israel, Givat Ram, Jerusalem, Israel 1 Chloride minerals; Drought; Floods; Food supply; Lakes; Rain; Solar radiation; Submarine geology, Climate variability; Eastern Mediterranean; Extreme events; Lake-sediment records; Medieval Climate Anomaly (MCA); Mediterranean; Northern Hemispheres; Paleoclimatic record, Climate change, aridity; climate change; climate variation; extreme event; lacustrine deposit; marine sediment; monsoon; paleoclimate; speleothem, Dead Sea; Ethiopia; Mediterranean Region https://www.scopus.com/inward/record.uri?eid=2-s2.0-85060031954&doi=10.3390%2fatmos10010029&partnerID=40&md5=4e4b1762f1c5999b94d4345a88970569 cited By 11 Y. Kushnir M. Stein article Umlauft20191550 Presently ongoing geodynamic processes within the intracontinental lithospheric mantle give rise to different natural phenomena in the NW Bohemia/Vogtland region (Czech Republic, Germany), amongst others: earthquake swarms, mineral springs and degassing zones of mantle-derived fluids as well as highly concentrated CO2 (mofettes). Their interaction mechanisms and relations are not yet fully understood, but fluid pathways within the crust are assumed, that allow efficient fluid transport between the main hypocentral swarm quake region and the degassing areas at the surface. Here, we focus on the location of the presumed fluid channels as well as on the investigation of their near-surface spatio-temporal variability, targeting a depth of a few hundreds of metmetres. We applied a 3-D matched field processing (MFP) approach in the frequency band of 10?20 Hz considering the fluid flow as seismic noise source. Within three campaigns in 2015/2016, we recorded continuous seismic noise data on the Hartoušov Mofette Field within the Cheb Basin (NW Bohemia, CZ), which is a key site to study fluid flow as it is characterized by strong and continuous surface degassing of CO2.We used temporary arrays varying in extent (70-600 m aperture) and in the amount of stations (25?95 units). Assuming a homogeneous velocity model and applying conventional MFP phase-matching over a 3-D grid search, we located two channel-like structures beneath the test site, which could be traced down to a common source area down to 2000 m depth. We thereby evaluated the influence of amplitude normalization of the measured noise signal on the MFP location considering water-filled or dry mofette channels. Additionally, a spatiotemporal analysis using time windows with a length of 10 min during 5 hr of noise record shows variability of fluid flow activity in space and time and hence, its migration beneath the test site on a short timescale. © 2019. Published by Oxford University Press on behalf of The Royal Astronomical Society. Article 2019 English 0956540X 10.1093/gji/ggz385 Geophysical Journal International 219 Oxford University Press 1550 – 1561 3 Bohemia; Czech Republic; Germany; Vogtland; Degassing; Earthquakes; Flow of fluids; Location; Mineral springs; Numerical models; Phase matching; Time series analysis; Continuous surface; Geodynamic process; Interaction mechanisms; Lithospheric mantle; Matched field processing; Seismic noise; Spatiotemporal analysis; Spatiotemporal variability; carbon dioxide; degassing; earthquake hypocenter; earthquake swarm; flow field; fluid flow; geodynamics; lithospheric structure; mantle structure; numerical model; seismic migration; seismic noise; seismic velocity; spatiotemporal analysis; three-dimensional modeling; time series analysis; Transport properties https://www.scopus.com/inward/record.uri?eid=2-s2.0-85072770056&doi=10.1093%2fgji%2fggz385&partnerID=40&md5=b2db1f1f0eb6a71acc192e5b76866571 Cited by: 8 J. Umlauft M. Korn article AssisFernandes2019289 This study presents 40Ar-39Ar step heating ages of four North American tektites (three bediasites and one georgiaite) and of two groundmass samples extracted at different depths from clast-rich impact melt rocks (CB-W61 and CB-W84) recovered by the USGS-ICDP Eyreville B drill-core about 9 km from the centre of the Chesapeake Bay impact structure. Radiometric age determination on both North American tektites and impact melt rocks from within Chesapeake Bay crater offers the first possibility to confirm the origin of these tektites. For this aim, argon isotopic data from 13 samples/aliquots of tektite rims, cores and bulk, and 4 samples/aliquots from two impact melt rocks were obtained over 15 to 26 step heating extractions. Age spectra of all tektite samples show plateaux comprising 62–98% of the 39Ar release over consecutive intermediate and high temperature heating steps. Few low temperature extractions indicate excess 40Ar. Inverse isochron 40Ar/36Ar intercepts of tektite samples are indistinguishable from air (295.5). However, impact melt rock spectra presented complex Ar-release affecting primarily the low temperature heating-steps. Inverse isochrones indicate excess argon from which the 40Ar/36Ar intercept was used to correct the age calculation. CB-W61 and CB-W61-2 40Ar/36Ar intercepts are 354.5 ± 2.5 and 327.2 ± 6.3, respectively, and those for CB-W84 and CB-W84-2 are 332.0 ± 7.3 and 329.6 ± 5.6, respectively. The inverse isochron weighted mean age (according to currently suggested K-decay constants revisions by Schwarz et al. (2011) and Renne et al. (2011)) for all four tektites is 34.86 ± 0.25 Ma (MSWD = 0.96, P = 0.41; n = 4) and for the two impact melt rocks is 37.16 ± 3.65 Ma (MSWD = 0.83, P = 0.36). The combined tektite and impact melt rocks isochron mean age of 34.86 ± 0.23 (0.32) Ma (MSWD = 0.87, P = 0.43) is slightly – though not significantly – higher than the plateau mean age of 34.55 ± 0.27 (0.36) Ma (MSWD = 0.66, P = 0.62). Placing this age in the Global Stratotype Section and Point (GSSP) marine section exposed at Massignano, Italy, it falls below the Eocene/Oligocene (E/O) boundary overlapping with the 10.28 m Ir-anomaly. These results agree within errors with previously reported ages of 35.20 ± 0.54 Ma, especially those derived from K-Ar and Ar-Ar total fusion analysis. An age of 34.86 ± 0.32 Ma sets the Chesapeake Bay impact event close to the youngest of the three Ir anomalies at ∼35.0 Ma in the case the impactor was Ir-rich (e.g, a chondrite, primitive achondrite, stony-iron or iron meteorite). The concordance with the E/O boundary at ∼33.9 Ma seems only marginally possible, and only if the Ir contribution from the ejecta were, potentially, due either to its small amount becoming diluted in the geologic record or the impactor being Ir poor, e.g., of differentiated achondritic composition. This study also brings to front the need to re-establish the stratigraphic and palaeo-magnetic correlations across the globe for the Ir-anomalies and the magneto-stratigraphy during the mid- to late-Eocene and early-Oligocene, and the need to re-evaluate the markers for the Eocene-Oligocene boundary. © 2019 Elsevier Ltd 2019 English 00167037 10.1016/j.gca.2019.03.004 Geochimica et Cosmochimica Acta 255 Elsevier Ltd 289-308 Museum für Naturkunde, Leibniz-Institute for Evolution and Biodiversity Research, Invalidenstraße 43, Berlin, 10115, Germany; School of Earth and Environmental Sciences, University of Manchester, Oxford Road, Manchester, M13 9PL, United Kingdom; Instituto Dom Luiz, University of Lisbon, Lisbon, 1749-016, Portugal; Klaus-Tschira-Labor für Kosmochemie, Institut für Geowissenschaften, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 234-236, Heidelberg, 69120, Germany; Saalbau Weltraum Projekt, Liebigstrasse 6, Heppenheim, 64646, Germany; Zentrum für Rieskrater und Impaktforschung (ZERIN), Nördlingen, Vordere Gerbergasse 3, Nördlingen, 86720, Germany; Florida Institute of Technology, Melbourne, FL 32901, United States argon-argon dating; Eocene-Oligocene boundary; geochronology; impact structure; magnetostratigraphy; melt; meteorite; paleomagnetism; tektite, Ascoli Piceno; Chesapeake Bay; Italy; Marche; Massignano; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-85063349910&doi=10.1016%2fj.gca.2019.03.004&partnerID=40&md5=a88b722be178770fe56331e4a1c9004b cited By 9 V. Assis Fernandes J. Hopp W.H. Schwarz J.P. Fritz M. Trieloff H. Povenmire article AssisFernandes2019289 This study presents 40Ar-39Ar step heating ages of four North American tektites (three bediasites and one georgiaite) and of two groundmass samples extracted at different depths from clast-rich impact melt rocks (CB-W61 and CB-W84) recovered by the USGS-ICDP Eyreville B drill-core about 9 km from the centre of the Chesapeake Bay impact structure. Radiometric age determination on both North American tektites and impact melt rocks from within Chesapeake Bay crater offers the first possibility to confirm the origin of these tektites. For this aim, argon isotopic data from 13 samples/aliquots of tektite rims, cores and bulk, and 4 samples/aliquots from two impact melt rocks were obtained over 15 to 26 step heating extractions. Age spectra of all tektite samples show plateaux comprising 62–98% of the 39Ar release over consecutive intermediate and high temperature heating steps. Few low temperature extractions indicate excess 40Ar. Inverse isochron 40Ar/36Ar intercepts of tektite samples are indistinguishable from air (295.5). However, impact melt rock spectra presented complex Ar-release affecting primarily the low temperature heating-steps. Inverse isochrones indicate excess argon from which the 40Ar/36Ar intercept was used to correct the age calculation. CB-W61 and CB-W61-2 40Ar/36Ar intercepts are 354.5 ± 2.5 and 327.2 ± 6.3, respectively, and those for CB-W84 and CB-W84-2 are 332.0 ± 7.3 and 329.6 ± 5.6, respectively. The inverse isochron weighted mean age (according to currently suggested K-decay constants revisions by Schwarz et al. (2011) and Renne et al. (2011)) for all four tektites is 34.86 ± 0.25 Ma (MSWD = 0.96, P = 0.41; n = 4) and for the two impact melt rocks is 37.16 ± 3.65 Ma (MSWD = 0.83, P = 0.36). The combined tektite and impact melt rocks isochron mean age of 34.86 ± 0.23 (0.32) Ma (MSWD = 0.87, P = 0.43) is slightly – though not significantly – higher than the plateau mean age of 34.55 ± 0.27 (0.36) Ma (MSWD = 0.66, P = 0.62). Placing this age in the Global Stratotype Section and Point (GSSP) marine section exposed at Massignano, Italy, it falls below the Eocene/Oligocene (E/O) boundary overlapping with the 10.28 m Ir-anomaly. These results agree within errors with previously reported ages of 35.20 ± 0.54 Ma, especially those derived from K-Ar and Ar-Ar total fusion analysis. An age of 34.86 ± 0.32 Ma sets the Chesapeake Bay impact event close to the youngest of the three Ir anomalies at ∼35.0 Ma in the case the impactor was Ir-rich (e.g, a chondrite, primitive achondrite, stony-iron or iron meteorite). The concordance with the E/O boundary at ∼33.9 Ma seems only marginally possible, and only if the Ir contribution from the ejecta were, potentially, due either to its small amount becoming diluted in the geologic record or the impactor being Ir poor, e.g., of differentiated achondritic composition. This study also brings to front the need to re-establish the stratigraphic and palaeo-magnetic correlations across the globe for the Ir-anomalies and the magneto-stratigraphy during the mid- to late-Eocene and early-Oligocene, and the need to re-evaluate the markers for the Eocene-Oligocene boundary. © 2019 Elsevier Ltd 2019 English 00167037 10.1016/j.gca.2019.03.004 Geochimica et Cosmochimica Acta 255 Elsevier Ltd 289-308 Museum für Naturkunde, Leibniz-Institute for Evolution and Biodiversity Research, Invalidenstraße 43, Berlin, 10115, Germany; School of Earth and Environmental Sciences, University of Manchester, Oxford Road, Manchester, M13 9PL, United Kingdom; Instituto Dom Luiz, University of Lisbon, Lisbon, 1749-016, Portugal; Klaus-Tschira-Labor für Kosmochemie, Institut für Geowissenschaften, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 234-236, Heidelberg, 69120, Germany; Saalbau Weltraum Projekt, Liebigstrasse 6, Heppenheim, 64646, Germany; Zentrum für Rieskrater und Impaktforschung (ZERIN), Nördlingen, Vordere Gerbergasse 3, Nördlingen, 86720, Germany; Florida Institute of Technology, Melbourne, FL 32901, United States argon-argon dating; Eocene-Oligocene boundary; geochronology; impact structure; magnetostratigraphy; melt; meteorite; paleomagnetism; tektite, Ascoli Piceno; Chesapeake Bay; Italy; Marche; Massignano; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-85063349910&doi=10.1016%2fj.gca.2019.03.004&partnerID=40&md5=a88b722be178770fe56331e4a1c9004b cited By 9 V. Assis Fernandes J. Hopp W.H. Schwarz J.P. Fritz M. Trieloff H. Povenmire article Yang20193106 The basic principle of diametrical core deformation analysis method(DCDA) in-situ stress testing method, core diameter testing instrument and testing process based on laser rangefinder were introduced, and the method was applied on the in-situ stress measurement of igneous rock strata on the base of 6 645-6 846 m in SK2. The results show that the core diameter curves after stress relief are sinusoidal with a periodic change of π, and the long axis and the short axis of the ellipse are nearly orthogonal. The test results conform with the theory results of DCDA method and can reflect the in-situ stress information. The direction of the elliptical long axis of core section is the direction of the maximum horizontal principal stress. According to the results of core paleomagnetic orientation, the maximum horizontal principal stress direction of 6 645-6 845 m in SK2 is determined to NE72°-83°. By taking into account the core elastic modulus and Poisson's ratio, the horizontal principal stress difference of 6 645 m in SK2 is determined to be about 35 MPa, and the horizontal principal stress difference of 6 845-6 846 m is about 55 MPa, which are almost consistent with the results of ASR in situ stress measurement. The successful application of DCDA method in the field of 6 645-6 846 m in SK2 well provides a new way to obtain the information of the deep in-situ stress, especially in the complex geological conditions of ultra deep or high temperature drilling and relatively broken formation. In this case, when the stress relief method and hydraulic fracturing method are difficult to implement, while the method can still obtain more reliable in-situ stress data. At the same time, this method is not limited by the depth and temperature environment of the borehole, and only needs nearly homogeneous and isotropic cylindrical core, and does not involve cutting and grinding the core, which is conducive to the reuse of the deep precious core. © 2019, Central South University Press. All right reserved. Article 2019 Chinese 16727207 10.11817/j.issn.1672-7207.2019.12.020 Zhongnan Daxue Xuebao (Ziran Kexue Ban)/Journal of Central South University (Science and Technology) 50 Central South University of Technology 3106 – 3113 12 Deformation; Igneous rocks; Indium compounds; Instrument testing; Range finders; Stress measurement; Stresses; Complex geological condition; Core diameters; Homogeneous and isotropic; Hydraulic fracturing methods; In-situ stress measurement; Insitu stress; Maximum horizontal principal stress; Temperature environments; Stress relief https://www.scopus.com/inward/record.uri?eid=2-s2.0-85079549089&doi=10.11817%2fj.issn.1672-7207.2019.12.020&partnerID=40&md5=fe5c948f5986125f8e24445451ed3f91 Cited by: 5 Yuehui Yang Dongsheng Sun Xiuhua Zheng Weiren Lin Awei Li article Hinz2019 Numerous experimental studies have shown that hydrate dissociation can result in significant strength reduction leading to sediment failure and unconsolidated flow behavior. In this work, a constitutive model for the effective permeability is developed that is capable of accurately modeling the evolution of permeability in hydrate reservoirs exhibiting unconsolidated behavior. A production phase that promotes sand production from an unconsolidated hydrate reservoir will result in a significant increase in permeability, such that the reservoir essentially behaves like a naturally fracking reservoir. Furthermore, installation of a sand screen to prevent sand production will throttle gas production due to the significant decrease in permeability as solids accumulate and compact at the sand screen. Our model was developed and verified using experimental data from the Mallik 2007/2008 production tests and can be applied in simulations of the coupled hydrodynamics, heat transfer, mass transfer, and geomechanics in the unconsolidated hydrate reservoir. © 2019 Elsevier B.V. 2019 English 18755100 10.1016/j.jngse.2019.103033 Journal of Natural Gas Science and Engineering 72 Elsevier B.V. Department of Chemical and Biological Engineering, Wanger Institute for Sustainable Energy Research (WISER), Illinois Institute of Technology, Chicago, IL, United States Gas industry; Heat transfer; Hydrates; Hydration; Mass transfer; Sand, Effective permeability; Gas productions; Hydrate dissociation; Mallik; Production phase; Simulation; Strength reduction; Unconsolidated, Petroleum reservoir engineering https://www.scopus.com/inward/record.uri?eid=2-s2.0-85073981373&doi=10.1016%2fj.jngse.2019.103033&partnerID=40&md5=1053d477fb9fea30670aa03498a03101 cited By 11 D. Hinz H. Arastoopour J. Abbasian article Sacchi201929 Large calderas are among the Earth's major volcanic features. They are associated with large magma reservoirs and elevated geothermal gradients. Caldera-forming eruptions result from the withdrawal and collapse of the magma chambers and produce large-volume pyroclastic deposits and later-stage deformation related to post-caldera resurgence and volcanism. Unrest episodes are not always followed by an eruption; however, every eruption is preceded by unrest. The Campi Flegrei caldera (CFc), located along the eastern Tyrrhenian coastline in southern Italy, is close to the densely populated area of Naples. It is one of the most dangerous volcanoes on Earth and represents a key example of an active, resurgent caldera. It has been traditionally interpreted as a nested caldera formed by collapses during the 100-200 km3 Campanian Ignimbrite (CI) eruption at ∼ 39 ka and the 40 km3 eruption of the Neapolitan Yellow Tuff (NYT) at ∼ 15 ka. Recent studies have suggested that the CI may instead have been fed by a fissure eruption from the Campanian Plain, north of Campi Flegrei. A MagellanPlus workshop was held in Naples, Italy, on 25-28 February 2017 to explore the potential of the CFc as target for an amphibious drilling project within the International Ocean Discovery Program (IODP) and the International Continental Drilling Program (ICDP). It was agreed that Campi Flegrei is an ideal site to investigate the mechanisms of caldera formation and associated post-caldera dynamics and to analyze the still poorly understood interplay between hydrothermal and magmatic processes. A coordinated onshore-offshore drilling strategy has been developed to reconstruct the structure and evolution of Campi Flegrei and to investigate volcanic precursors by examining (a) the succession of volcanic and hydrothermal products and related processes, (b) the inner structure of the caldera resurgence, (c) the physical, chemical, and biological characteristics of the hydrothermal system and offshore sediments, and (d) the geological expression of the phreatic and hydromagmatic eruptions, hydrothermal degassing, sedimentary structures, and other records of these phenomena. The deployment of a multiparametric in situ monitoring system at depth will enable near-real-time tracking of changes in the magma reservoir and hydrothermal system. © Author(s) 2019. 2019 English 18168957 10.5194/sd-26-29-2019 Scientific Drilling 26 Copernicus GmbH 29-46 Istituto di Scienze Marine (ISMAR), Consiglio Nazionale Delle Ricerche (CNR), Calata Porta di Massa, Naples, 80133, Italy; Istituto Nazionale di Geofisica e Vulcanologia (INGV), Sezione di Napoli, Via Diocleziano, 328, Naples, 80124, Italy; Faculty of Geosciences, University of Bremen, Klagenfurter Str., Bremen, 28359, Germany; Dipartimento di Scienze Geologiche, Università degli Studi Roma Tre, Largo S.L. Murialdo, 1, Rome, 00146, Italy; Dipartimento di Scienze della Terra e Del Mare (DiSTeM), Università degli Studi di Palermo, Via Archirafi, 22, Palermo, 90123, Italy; College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR 97331, United States; Dipartimento di Scienze della Terra, dell'Ambiente e Delle Risorse (DiSTAR), Università degli Studi di Napoli Federico II, Via Cinthia, 21, Naples, 80126, Italy; Geological Survey of Japan, National Institute of Advanced Industrial Science and Technology, AIST Tsukuba Central 7, 1-1-1 Higashi, Tsukuba, Ibaraki, 305-8567, Japan; UCL Hazard Centre, Department of Earth Sciences, University College London, Gower Street, London, WC1E 6BT, United Kingdom; Institut de Ciències de la Terra Jaume Almera, Consejo Superior de Investigaciones Científicas (CSIC), C/Lluís Solé i Sabarís s/n, Barcelona, 08028, Spain; Istituto di Scienze dell'Alimentazione (ISA), Consiglio Nazionale Delle Ricerche (CNR), Via Roma, 64, Avellino, 83100, Italy; GEOMAR Helmholtz Centre for Ocean Research Kiel, Wischhofstr. 1-3, Kiel, 24148, Germany; Istituto Nazionale di Geofisica e Vulcanologia (INGV), Via di Vigna Murata, 605, Rome, 00143, Italy Biology; Infill drilling; Offshore oil well production; Sedimentology; Volcanoes, Biological characteristic; Caldera-forming eruption; Campanian Ignimbrite; Geothermal gradients; Hydromagmatic eruptions; Hydrothermal products; Neapolitan yellow tuffs; Sedimentary structure, Offshore drilling https://www.scopus.com/inward/record.uri?eid=2-s2.0-85076110893&doi=10.5194%2fsd-26-29-2019&partnerID=40&md5=d8803c633f6b569ceca00b2cdd727f59 cited By 5 M. Sacchi G. De Natale V. Spiess L. Steinmann V. Acocella M. Corradino S. De Silva A. Fedele L. Fedele N. Geshi C. Kilburn D. Insinga M.-J. Jurado F. Molisso P. Petrosino S. Passaro F. Pepe S. Porfido C. Scarpati H.-U. Schmincke R. Somma M. Sumita S. Tamburrino C. Troise M. Vallefuoco G. Ventura article Dhulipudi2019 Analysis and comparison of geophysical logs from seven exploratory boreholes of 1–1.5 km depth in the Koyna-Warna region of India illustrate variations in physical properties and structural characteristics of the basalts and underlying granite-gneiss basement in and around the seismogenic zone. In the north, south of the Koyna reservoir, densities are higher, gamma values are lower, fractures dip at high angles with low fracture permeabilities. To the south, around the Warna reservoir, densities are lower, gamma values higher, and resistivity values are low. In the southernmost borehole at Khadi, basement is highly fractured, and there are significant amounts of water outflow associated with the fracture system. The fracture density increases to the south, with fracture dips ranging from medium to low angles with permeability values two orders of magnitude higher than in the northern boreholes. These variations in physical and structural properties resulting in a highly heterogeneous crust, reflect the cumulative effect of episodes of tectonic activity over millions of years that this region has undergone. © 2019 Elsevier B.V. 2019 English 00319201 10.1016/j.pepi.2019.106311 Physics of the Earth and Planetary Interiors 296 Elsevier B.V. CSIR-National Geophysical Research Institute, Hyderabad, India Boreholes; Buildings; Exploratory boreholes; Fracture; Geophysics; Reservoirs (water); Structural geology, ATV images; Crustal heterogeneity; Fracture pattern; Geophysical logs; Koyna-Warna, Well logging, assessment method; borehole; fracture propagation; geophysical method; heterogeneity; permeability; tectonic setting, Deccan; India, Ambystoma tigrinum stebbensi virus https://www.scopus.com/inward/record.uri?eid=2-s2.0-85073733125&doi=10.1016%2fj.pepi.2019.106311&partnerID=40&md5=a52d7ce6f98f6cd4346767f2a932fa00 cited By 3 G. Dhulipudi S. Nittala K. Arora S.R. Mannepalli S. K.N.S.S.S S. Yadavally S.V.K. Potharaju S. H.V.S. article Marra2019280 Article 2019 10.1016/j.advwatres.2019.04.002 Advances in Water Resources 127 280 – 290 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85063991138&doi=10.1016%2fj.advwatres.2019.04.002&partnerID=40&md5=02b5972b7f8d51b50ece317079a2b268 Cited by: 77 Francesco Marra Davide Zoccatelli Moshe Armon Efrat Morin article Cevallos-Ferriz2019193 A fragment of mummified wood collected from a Quaternary sedimentary sequence of Lake Chalco, Central Mexico, in the depocenter of the Basin (19°15'26"N, 98°58'32"W), has anatomical characteristics of Abies. Identification is based on the presence of a warty layer in the walls of the tracheids, prismatic crystals in ray cells, taxodioid pits in the cross-fields, and lack of ray tracheids and normal intercellular canals, among other well-preserved characteristics. This specimen represents the first macrofossil evidence of the genus in this region and suggests that by the late Quaternary it was already established in the surroundings of Lake Chalco, and most probably in what is now central Mexico. Unfortunately, as with morphological and genetic characteristics, the anatomical attributes of the wood of the genus have not been useful for the delimitation of species. Most wood characteristics have been considered of little diagnostic value. However, comparison of available anatomical descriptions of fossil and living species highlight differences among them, even with Abies religiosa wood, which is the closest species to Lake Chalco. Other characteristics or plant organs are needed to assemble a whole plant that can be used to establish phylogenetic relationships and clarify the evolutionary history of the genus. Meanwhile this wood is assigned to a new fossil taxon, Abies cuitlahuacii Cevallos-Ferriz, Ríos-Santos & Lozano-García. © Boletín de la Sociedad Geológica Mexicana 2019. 2019 English 14053322 10.18268/BSGM2019v71n1a10 Boletin de la Sociedad Geologica Mexicana 71 Instituto de Geología, Universidad Nacional Autónoma de México 193-206 Instituto de Geología, Universidad Nacional Autónoma de México, Ciudad Universitaria, Circuito de la Investigación Científica, Coyoacán CDMX, 04510, Mexico; Posgrado en Ciencias Biológicas, Instituto de Geología, Universidad Nacional Autónoma de México, Ciudad Universitaria, Circuito de la Investigación Científica, Coyoacán CDMX, 04510, Mexico 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85067013155&doi=10.18268%2fBSGM2019v71n1a10&partnerID=40&md5=405f531eeb1da4535ace3a8fbd1af4bc cited By 1 S.R.S. Cevallos-Ferriz C. Ríos-Santos S. Lozano-García article Lahti2019351 The Outokumpu belt in eastern Finland is known for numerous polymetallic (Cu-Co-Zn-Ni-Ag-Au) sulphide ore deposits and it is a potential area for new discoveries. Audiomagnetotelluric (AMT) data have recently been collected to image the subsurface conductivity structure of the belt. The data were acquired along five profiles aiming to explore deep conductors, study their geometry and investigate the deep conductivity structure of the belt.The acquired AMT data were mostly adequate for 2D inversion, as the survey area is characterised by thin, laterally extensive conductors indicated by airborne electromagnetic data, deep drillings and regional strike analysis of the impedance tensor data. 2D smooth inversion was carried out jointly for transverse electric and transverse magnetic data. The results show southeast-dipping and sub-horizontal continuous conductors southeast of the Outokumpu old mine, suggesting the presence of prospective Outokumpu assemblage rocks. One ∼ 1 km deep sub-horizontal conductor is verified by a deep drill-hole located ∼ 8 km southeast of the mine. The results demonstrate a similar southeast-dipping structure in the Vuonos mine area, which is located ∼ 7 km northeast of the Outokumpu old mine. An eastwards-dipping conductor detected in the Miihkali serpentinite area indicates deep exploration potential in this area. Besides the smooth 2D inversion, a sharp-boundary 2D inversion was performed and the resulting model was assessed with the existing geological interpretation of the Miihkali area. In the area of the Sotkuma gneiss inlier, conductors are absent from the uppermost ∼ 6 km. This feature may represent an uplifted fault block rather than a thin thrust sheet of Archaean basement rocks. © 2019 Australian Society of Exploration Geophysics. Article 2019 English 08123985 10.1080/08123985.2019.1606200 Exploration Geophysics 50 Taylor and Francis 351 – 363 4 Finland; Outokumpu; Pohjois-Karjala; Gold compounds; Gold deposits; Infill drilling; Magnesite; Magnetotellurics; Sulfur compounds; Surveys; Zinc deposits; 2D modelling; Airborne electromagnetic; Conductivity structures; Exploration potential; Geological interpretation; Horizontal conductors; Transverse electrics; Transverse magnetic; Archean; basement rock; fault zone; geometry; gneiss; mineral exploration; mining industry; ore body; serpentinite; Mineral exploration https://www.scopus.com/inward/record.uri?eid=2-s2.0-85066971435&doi=10.1080%2f08123985.2019.1606200&partnerID=40&md5=d3a462f1cca18710c5ebe7617771144f Cited by: 2 Ilkka Lahti Asko Kontinen Vesa Nykänen article Ma2019350 Thermal conductivity is an important parameter to study the deep thermal structure of the sedimentary basin. The traditional way to obtain the thermal conductivity by measurement of deep core test is limited by funding, sampling conditions and some other factors. Meanwhile, due to the reason that geothermal wells are affected by temperature and pressure conditions, indoor test results cannot represent the in-situ thermal conductivity of the rocks. In this study, the measured thermal conductivity and logging parameters of cores from 3 289 to 4 536 meters in the third spudding of well Songke 2 are obtained, and the relationship between thermal conductivity of sandstone, mudstone and rhyolite and logging parameters was analyzed. The results show that correlation between porosity, wave velocity and thermal conductivity of sandstone logging parameters is obvious, but the correlation for mudstone and rhyolite is not high. On such a basis, the authors analyzed the influence of temperature and pressure on the thermal conductivity of the Songliao Basin. It is concluded that the thermal conductivity of the third spudding of well Songke 2 in Songliao Basin is reduced by about 30% due to temperature effect, and the thermal conductivity is increased by about 10% due to pressure effect compared with 36the measured values in laboratory. The results of this study can provide a new idea for the acquisition of deep thermal conductivity and geothermal flow value of basins in China, especially for some abandoned wells with logging dates but can not obtain deep cores. © 2019, Science Press. All right reserved. Article 2019 Chinese 10063021 10.3975/cagsb.2019.021101 Acta Geoscientica Sinica 40 Science Press 350 – 360 2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85067111690&doi=10.3975%2fcagsb.2019.021101&partnerID=40&md5=80c8bd4c06f5e15b8b02890bb9fbdf8d Cited by: 7 Feng Ma Gui-Ling Wang Zhan-Xue Sun Wei Zhang He-Sheng Hou Xiao-Yang Guo article Kelemen2019 Review 2019 10.3389/fclim.2019.00009 Frontiers in Climate 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85123282754&doi=10.3389%2ffclim.2019.00009&partnerID=40&md5=343e04c6b34e8153ade416eb6bbd5148 Cited by: 407; All Open Access, Gold Open Access Peter Kelemen Sally M. Benson Hélène Pilorgé Peter Psarras Jennifer Wilcox article simon_anisotropic_2019 SUMMARY. A remarkably well preserved representation of a deeply eroded Palaeozoic orogen is found in the Scandinavian Caledonides, formed by the collision of t 2019 oct en 0956-540X 10.1093/gji/ggz286 Geophysical Journal International 219 66--79 1 https://academic.oup.com/gji/article/219/1/66/5522608 Publisher: Oxford Academic H. Simon P. Hedin C. Juhlin F. Krauß R. Giese article Lowe201934 Article 2019 10.1016/j.precamres.2019.02.024 Precambrian Research 327 34 – 46 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85062402999&doi=10.1016%2fj.precamres.2019.02.024&partnerID=40&md5=38780e6d8a5b223f56bb2d68056c90b4 Cited by: 14; All Open Access, Bronze Open Access Donald R. Lowe Nadja Drabon Gary R. Byerly article Li20191200 Deep-well combined drill string technology has become one of the most important scheme to solve the super-long drill string used for ultra-deep drilling project, which is related to equipment capacity, material property, drilling conditions and string mechanics. In this paper, the application and development of combined drill string technology in geological drilling are summarized systematically, the design scheme and its limitation length are discussed in detail on the basis of strength theory. The results show that the drilling mission with the depth of 13000m could not be finished by simply using pure steel combined drill string with the final borehole diameter being 216mm. By using drill string consisting of V150 steel drill pipe & titanium alloy drill pipe and S135 steel drill pipe & aluminum alloy drill pipe, the limitation depth and the weight of each combined drill string are respectively 13484m, 18783m and 360.5, 324.3t; in this way both of them own application reliability and advantage. These results have reference significance to the design and selection of deep-well combined drill string used for ultra-deep drilling project. © 2019 Editorial Board of Geology in China. All rights reserved. 2019 Chinese 10003657 10.12029/gc20190520 Geology in China 46 Science Press 1200-1208 Chinese Academy of Geological Sciences, Beijing, 100037, China; China Deep Exploration Center, China Geological Survey, Chinese Academy of Geological Sciences, Beijing, 100037, China; Institute of Exploration Techniques, CAGS, Hebei, Langfang, 065000, China; China University of Geosciences (Wuhan), Hubei, Wuhan, 430074, China 5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85113281700&doi=10.12029%2fgc20190520&partnerID=40&md5=4ba670f469722b81c357bd05e78d8098 cited By 1 L. Li F. Zhang W. Wang Y. Zhang Y. Hu article Goswami20196101 Delineation of subsurface faults and damage zones is a major goal of scientific drilling projects in seismically active areas. Geophysical logs acquired in a 3-km deep scientific borehole KFD1 in the Koyna seismogenic zone, a site of recurrent reservoir triggered seismicity over the past 55 years, provide an unprecedented opportunity to investigate the rock properties and delineate the fault zones. KFD1 passed through 1,247-m thick Deccan traps and continued for 1,767 m into the underlying granitic basement rocks that host the seismic activity in the depth range 2–10 km. We have studied the physical properties and acoustic behavior of basement granitoids from the analysis of geophysical logs from 1,500 to 3,000 m. Salient results are as follows. (1) Seven anomalous zones are identified below 2,100-m depth based on electrical resistivity, caliper, density, neutron porosity, self-potential, and sonic data. (2) The anomalous zones are characterized by significant shear wave velocity anisotropy (up to 25%), as revealed by cross-dipole sonic data. (3) Dispersion analysis of dipole flexural modes confirms that the anisotropy is primarily stress induced; fast polarized shear wave azimuth (FSA) therefore indicates the orientation of maximum horizontal compressive stress SHmax. (4) Comparison of FSA with independent estimates of SHmax orientations obtained from drilling induced tensile fractures and strike of inclined fractures in the anisotropic zones shows that FSA is controlled mainly by the stress regime. Therefore, the stress rotations inferred from anisotropy analyses in the anomalous zones indicate their association with subsurface fault damage zones. ©2019. American Geophysical Union. All Rights Reserved. 2019 English 21699313 10.1029/2018JB017257 Journal of Geophysical Research: Solid Earth 124 Blackwell Publishing Ltd 6101-6120 Ministry of Earth Sciences, Borehole Geophysics Research Laboratory, Karad, Maharashtra, India 6 acoustic logging; damage; fault zone; granitoid; reservoir-induced seismicity; rock property; seismic anisotropy; seismic zone; sonic boom; stress field; structural control, India; Koyna; Maharashtra https://www.scopus.com/inward/record.uri?eid=2-s2.0-85068168197&doi=10.1029%2f2018JB017257&partnerID=40&md5=407fc4287915c4c4522ee84b04e85b93 cited By 14 D. Goswami S. Roy V.V. Akkiraju article Nickschick20191951 <p>The Cheb Basin, a region of ongoing swarm earthquake activity in the western Czech Republic, is characterized by intense carbon dioxide degassing along two known fault zones - the N-S-striking Počatky-Plesná fault zone (PPZ) and the NW-SE-striking Mariánské Lázne fault zone (MLF). The fluid pathways for the ascending <span classCombining double low line"inline-formula">CO2</span> of mantle origin are one of the subjects of the International Continental Scientific Drilling Program (ICDP) project "Drilling the Eger Rift" in which several geophysical surveys are currently being carried out in this area to image the topmost hundreds of meters to assess the structural situation, as existing boreholes are not sufficiently deep to characterize it.</p> <p>As electrical resistivity is a sensitive parameter to the presence of conductive rock fractions as liquid fluids, clay minerals, and also metallic components, a large-scale dipole-dipole experiment using a special type of electric resistivity tomography (ERT) was carried out in June 2017 in order to image fluid-relevant structures. We used permanently placed data loggers for voltage measurements in conjunction with moving high-power current sources to generate sufficiently strong signals that could be detected all along the 6.5&thinsp;<span classCombining double low line"inline-formula">km</span> long profile with 100 and 150&thinsp;<span classCombining double low line"inline-formula">m</span> dipole spacings. After extensive processing of time series for voltage and current using a selective stacking approach, the pseudo-section is inverted, which results in a resistivity model that allows for reliable interpretations depths of up than 1000&thinsp;<span classCombining double low line"inline-formula">m</span>.</p> <p>The subsurface resistivity image reveals the deposition and transition of the overlying Neogene Vildštejn and Cypris formations, but it also shows a very conductive basement of phyllites and granites that can be attributed to high salinity or rock alteration by these fluids in the tectonically stressed basement. Distinct, narrow pathways for <span classCombining double low line"inline-formula">CO2</span> ascent are not observed with this kind of setup, which hints at wide degassing structures over several kilometers within the crust instead. We also observed gravity and GPS data along this profile in order to constrain ERT results. A gravity anomaly of ca. <span classCombining double low line"inline-formula">-9</span>&thinsp;<span classCombining double low line"inline-formula">mGal</span> marks the deepest part of the Cheb Basin where the ERT profile indicates a large accumulation of conductive rocks, indicating a very deep weathering or alteration of the phyllitic basement due to the ascent of magmatic fluids such as <span classCombining double low line"inline-formula">CO2</span>. We propose a conceptual model in which certain lithologic layers act as caps for the ascending fluids based on stratigraphic records and our results from this experiment, providing a basis for future drillings in the area aimed at studying and monitoring fluids.</p>. © Author(s) 2019. 2019 English 18699510 10.5194/se-10-1951-2019 Solid Earth 10 Copernicus GmbH 1951-1969 Institute for Geophysics and Geology, Leipzig University, Talstrasse 35, Leipzig, 04103, Germany; Leibniz Institute for Applied Geophysics, Stilleweg 2, Hanover, 30655, Germany; Institute of Geophysics CAS, Boční II 1401, Prague, 141 31, Czech Republic 6 Buildings; Carbon dioxide; Degassing; Drilling fluids; Electric conductivity; Geophysics; Global positioning system; Infill drilling; Stratigraphy; Weathering, Continental scientific drillings; Earthquake activity; Electric resistivity tomography; Electrical resistivity tomography; Geophysical surveys; Resistivity modeling; Sensitive parameter; Stratigraphic records, Electric lines, carbon dioxide; degassing; earthquake swarm; electrical resistivity; fault zone; monitoring; tomography, Cheb Basin; Czech Republic; Karlovarsky https://www.scopus.com/inward/record.uri?eid=2-s2.0-85075055625&doi=10.5194%2fse-10-1951-2019&partnerID=40&md5=4b9a0e021e789ab0a50916d1fce58fa5 cited By 7 T. Nickschick C. Flechsig J. Mrlina F. Oppermann F. Löbig article trumbull2029bushveld 2019 Geobulletin 62 31--32 4 R Trumbull D Khoza F Roelofse S Webb R Klemd L Ashwal article sd-25-63-2019 2019 10.5194/sd-25-63-2019 Scientific Drilling 25 63--70 https://sd.copernicus.org/articles/25/63/2019/ T. Haberzettl G. Daut N. Schulze V. Spiess J. Wang L. Zhu Party article Rae20191960 Porosity and its distribution in impact craters has an important effect on the petrophysical properties of impactites: seismic wave speeds and reflectivity, rock permeability, strength, and density. These properties are important for the identification of potential craters and the understanding of the process and consequences of cratering. The Chicxulub impact structure, recently drilled by the joint International Ocean Discovery Program and International Continental scientific Drilling Program Expedition 364, provides a unique opportunity to compare direct observations of impactites with geophysical observations and models. Here, we combine small-scale petrographic and petrophysical measurements with larger-scale geophysical measurements and numerical simulations of the Chicxulub impact structure. Our aim is to assess the cause of unusually high porosities within the Chicxulub peak ring and the capability of numerical impact simulations to predict the gravity signature and the distribution and texture of porosity within craters. We show that high porosities within the Chicxulub peak ring are primarily caused by shock-induced microfracturing. These fractures have preferred orientations, which can be predicted by considering the orientations of principal stresses during shock, and subsequent deformation during peak ring formation. Our results demonstrate that numerical impact simulations, implementing the Dynamic Collapse Model of peak ring formation, can accurately predict the distribution and orientation of impact-induced microfractures in large craters, which plays an important role in the geophysical signature of impact structures. ©2019. American Geophysical Union. All Rights Reserved. 2019 10.1029/2019JE005929 Journal of Geophysical Research: Planets 124 1960-1978 Department of Earth Science and Engineering, Imperial College London, London, United Kingdom; Institut für Geo- und Umweltnaturwissenschaften, Albert-Ludwigs-Universität Freiburg, Geologie, Freiburg, Germany; Imaging and Analysis Centre, Natural History Museum, London, United Kingdom; Institute for Geophysics and Department of Geological Sciences, Jackson School of Geosciences, University of Texas at Austin, Austin, TX, United States; Gèosciences Montpellier, Universitè de Montpellier, Montpellier, France; Institut für Geologie, Universität Hamburg, Hamburg, Germany; Alfred Wegener Institute, Helmholtz Centre of Polar and Marine Research, Bremerhaven, Germany; Department of Earth Sciences/Centre for Planetary Science and Exploration, Western University, London, ON, Canada 7 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85070207698&doi=10.1029%2f2019JE005929&partnerID=40&md5=6440580a2a4ab3c7d2bca7e6d22e8598 cited By 17 A.S.P. Rae G.S. Collins J.V. Morgan T. Salge G.L. Christeson J. Leung J. Lofi S.P.S. Gulick M. Poelchau U. Riller C. Gebhardt R.A.F. Grieve G.R. Osinski book WangChengshan2019Iroc 2019 eng 9780128129289 Initial report of continental scientific drilling project of the Cretaceous Songliao Basin (SK-1) in China Elsevier

Amsterdam, The Netherlands ; Cambridge, MA

Boring -- China -- Heilongjiang Sheng; Boring -- China -- Jilin Sheng; Boring -- China -- Liaoning Sheng Chengshan Wang article Mngadi201979 Article 2019 10.1016/j.ijrmms.2018.10.003 International Journal of Rock Mechanics and Mining Sciences 114 79 – 91 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85059346741&doi=10.1016%2fj.ijrmms.2018.10.003&partnerID=40&md5=91e21c98f3e1dbe76a089d1958554ddc Cited by: 24 S.B. Mngadi R.J. Durrheim M.S.D. Manzi H. Ogasawara Y. Yabe H. Yilmaz N. Wechsler G. Van Aswegen D. Roberts A.K. Ward M. Naoi H. Moriya M. Nakatani A. Ishida SATREPS Team ICDP DSeis Team article Gupta2019469 The Koyna earthquake of M 6.3 on December 10, 1967 is the largest artificial water reservoir triggered earthquake globally. It claimed ∼ 200 human lives and devastated the Koyna township. Before the impoundment of the Shivaji Sagar Lake created by the Koyna Dam, there were no earthquakes reported from the region. Initially a few stations were operated in the region by the CentralWater and Power Research Station (CWPRS). The seismic station network grew with time and currently the National Geophysical Research Institute (NGRI), Hyderabad is operating 23 broadband seismographs and 6 bore hole seismic stations. Another reservoir, Warna, was created in 1985, which provided a further impetus to Reservoir Triggered Seismicity (RTS). Every year following the monsoon, water levels rise in the two reservoirs and there is an immediate increase in triggered earthquakes in the vicinity of Koyna-Warna reservoirs in the months of August–September. Peak RTS is observed in September and later during December.Another spurt in triggered earthquakes is observed during the draining of the reservoirs in the months of April- May. A comparative study of RTS earthquake sequences and the ones occurring in nearby regions made it possible to identify four common characteristics of RTS sequences that discriminate them from normal earthquake sequences. As the RTS events continue to occur at Koyna in a large number in a limited area of 20 km x 30 km, at shallow depths (mostly 2 to 9 km), the region being accessible for all possible observations and there being no other source of earthquakes within 100 km of Koyna Dam, it was suggested to be an ideal site for near field observations of earthquakes. This suggestion was discussed by the global community at an ICDP sponsored workshop held at Hyderabad and Koyna in 2011. There was an unanimous agreement about the suitability of the site for deep scientific drilling; however, a few additional observations/experiments were suggested. These were carried out in the following three years and another ICDP workshop was held in 2014, which totally supported setting up a borehole laboratory for near field investigations at Koyna. Location of a Pilot Bore-hole was decided on the basis of seismic activity and other logistics. The 3 km deep Pilot Borehole was spudded on December 20, 2016 and completed on June 11, 2017. © 2017, Geological Society of India. Review 2019 English 00167622 10.1007/S12594-017-0771-2 Proceedings of the Indian National Science Academy 85 Geological Society of India 469 – 480 CSIR- National Geophysical Research Institute, Hyderabad, 500 007, India 2 comparative study; earthquake event; earthquake trigger; reservoir; reservoir-induced seismicity; seismic discrimination; seismograph; site investigation, India; Koyna Dam; Maharashtra https://www.scopus.com/inward/record.uri?eid=2-s2.0-85087000299&doi=10.1007%2fS12594-017-0771-2&partnerID=40&md5=88389dc8fda8a9a7e6a94a74c90b260a Cited by: 3 Harsh K. Gupta article Coianiz2019175 Sequence architecture and depositional sequences of the Quaternary lacustrine succession deposited in the northern Dead Sea sub-basin were examined using logging data collected during the 2010-2011 ICDP campaign. Methods borrowed from sequence stratigraphy techniques were used to investigate the characteristics of sediments deposited in the central part of the northern lake. High resolution wire logging data combined with a detailed lithological description of the ICDP 5017-1-A deep borehole were used to examine depositional systems and related processes controlling their formation. Analysis of sedimentary stacking patterns and stratal surfaces within the late Pleistocene-Holocene lacustrine succession revealed 10 depositional sequences. It was possible to identify key stratal boundaries and to discern between three sedimentary stacking patterns interpreted here as representing lowstand systems tracts (LST), transgressive systems tracts (TST) and highstand systems tracts (HST). Examined together, they may be interpreted in terms of relative lake level changes. On the basis of the stratigraphic analysis complemented with new age dating, this article presents a record of the sediment accumulation pattern and a relative lake level curve reconstructed for the last ca 225 ka. Results show that stratigraphic units and depositional and erosional surfaces examined in the deep 5017-1-A borehole can be correlated to the proximal area of the basin. This means that changes in relative lake levels were generally synchronous and uniform across the Dead Sea basin. The creation of accommodation space in the northern Dead Sea was found to generally be in phase with paleoclimatic modulating lake levels, and not due to tectonics. © 2019 Elsevier Ltd 2019 English 02773791 10.1016/j.quascirev.2019.03.009 Quaternary Science Reviews 210 Elsevier Ltd 175-189 Dr. Moses Strauss Department of Marine Geosciences, Leon H. Charney School of Marine Sciences, University of Haifa, Mt. Carmel, 31905, Israel; Department of Geophysics and Planetary Sciences, Faculty of Exact Sciences, Tel Aviv University, Ramat Aviv, 69978, Israel; Mediterranean Sea Research Centre of Israel (MERCI), University of Haifa, Haifa, 3498838, Israel Boreholes; Deposition; Lakes; Lithology; Sedimentology, Depositional sequences; High resolution sequence stratigraphy; Highstand systems tract; Late Pleistocene-Holocene; Sequence architectures; Sequence stratigraphy; Stratigraphic analysis; Transgressive systems tracts, Stratigraphy, data set; depositional environment; depositional sequence; lacustrine deposit; lake level; paleoclimate; Pleistocene-Holocene boundary; Quaternary; reconstruction; sequence stratigraphy, Dead Sea https://www.scopus.com/inward/record.uri?eid=2-s2.0-85062832348&doi=10.1016%2fj.quascirev.2019.03.009&partnerID=40&md5=1b58c2834616eeb54a29eb395b7e9865 cited By 5 L. Coianiz O.M. Bialik Z. Ben-Avraham M. Lazar article Cosgrove20191291 Trajectories of successive clinoform rollovers are widely applied to predict patterns of spatio-temporal sand distribution. However, the detailed internal architecture of individual clinothems is rarely documented. Understanding the textural complexities of complete topset-foreset-bottomset clinothem sequences is a key factor in understanding how and when sediment is transferred basinward. This study used high-resolution, core-based analyses of 267 samples from three research boreholes from quasi-coeval topset, foreset, and bottomset deposits of a single Miocene intrashelf clinothem recovered during Integrated Ocean Drilling Program (IODP) Expedition 313, offshore New Jersey, USA. Topset deposits were subdivided into three sedimentary packages based on grain character and facies analysis, consisting of upper and lower river-dominated topset process-regime packages separated by a middle wave- and storm-dominated process-regime package. Temporal variability in topset process regime exerts a quantifiable effect on grain character across the complete depositional profile, which was used here to correlate topset deposits with time-equivalent sedimentary packages in foreset and bottomset positions. River-dominated sedimentary packages have higher sand-to-mud ratios; however, the grain character of river-dominated sedimentary packages is texturally less mature than that of wave- and storm-dominated deposits. Differences in grain character between packages dominated by different process regimes increase basinward. The novel use of quantitative grain-character data allows intraclinothem time lines to be established at a higher resolution than is possible using chronostratigraphic techniques. Additionally, stratigraphic changes in grain character were used to refine the placement of the basal sequence boundary. These results challenge the idea that clinoform trajectories and stacking patterns are sufficient to describe spatio-temporal sand-body evolution across successive clinothems. © 2019 The Authors. 2019 English 1553040X 10.1130/GES02046.1 Geosphere 15 Geological Society of America 1291-1322 School of Earth and Environment, University of Leeds, Leeds, LS2 9JT, United Kingdom 4 Deposits; Offshore boreholes; Offshore oil well production; Rivers; Sedimentology; Storms; Stratigraphy, Higher resolution; Integrated ocean drilling programs; Internal architecture; Sand distribution; Sedimentary packages; Stratigraphic changes; Temporal variability; Textural complexity, Sand, chronostratigraphy; correlation; deposition; facies analysis; Miocene; Ocean Drilling Program; offshore application; resolution; sand; sedimentary structure, New Jersey; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-85070791459&doi=10.1130%2fGES02046.1&partnerID=40&md5=66f6b138649dd2fcae52dadc4d71ce4a cited By 3 G.I.E. Cosgrove D.M. Hodgson N.P. Mountney W.D. McCaffrey article DeCort2019279 Article 2019 10.1007/s10933-019-00092-2 Journal of Paleolimnology 62 279 – 300 3 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85072051045&doi=10.1007%2fs10933-019-00092-2&partnerID=40&md5=a9b9a6475fe1c599028d9e9a2763f0d1 Cited by: 11 Gijs De Cort Florias Mees Robin W. Renaut Matthias Sinnesael Thijs Meeren Steven Goderis Edward Keppens Anthony Mbuthia Dirk Verschuren conference Andika2019 Multiple attenuation effect study in Lake Towuti seismic data is based on limited offset recording. The goal of this study is to better understand the sediments structure of Lake Towuti that layered above East Sulawesi ophiolitic and metamorphic rocks for stratigraphic interpretation. Surface-related multiple and internal multiple are a common noise signal that recorded in this seismic data, alongside the primary signal from the sediments layer. In order to get a representative subsurface image of the lake, a combination of some de-multiple method to suppress this noise signal has been applied in previous study. However, the line seismic that used in this seismic recording is less than 100 m. From our perspective, this limited offset line fact have to be considered carefully. It's because some application of de-multiple method in this case will not effectively suppress the noise. In this study, we give an alternative combination method in function to put out the surface-related multiple of the case. First, we enhance the S/N ratio and velocity analysis of the data by Common Reflection Surface (CRS) method. From this enhancement, CRS can give a direct advantage when applying some de-multiple method, especially in Predictive Deconvolution and SRME method. Moreover, we combine the application of de-multiple theory with the strict arrangement of Predictive Deconvolution, Surface-Related Multiple Elimination (SRME), and the last is F-K filter. Those combination methods precisely give a better imaging of Lake Towuti sediments layer in this seismic processing study. © 2019 Published under licence by IOP Publishing Ltd. Conference paper 2019 English 17551307 10.1088/1755-1315/279/1/012033 IOP Conference Series: Earth and Environmental Science 279 Institute of Physics Publishing Azis M.I. 1 Metamorphic rocks; Sediments; Seismic prospecting; Seismic response; Seismic waves; Stratigraphy; Combination method; Common reflection surfaces; Multiple attenuation; Predictive deconvolution; Seismic processing; Seismic recording; Subsurface images; Surface-related multiple elimination; Lakes https://www.scopus.com/inward/record.uri?eid=2-s2.0-85072639481&doi=10.1088%2f1755-1315%2f279%2f1%2f012033&partnerID=40&md5=acd394e15740c12592d71ce5edbab714 Cited by: 0; All Open Access, Bronze Open Access Ryan Bobby Andika Wahyu Triyoso Satria Bijaksana Abd. Hafidz James M. Russell Nigel Watruss article ZHAOJinhuan <p>In order to conduct long-term deep observation, fluid experiments and investigate volcanic events in Songliao basin, the authors carried out lithological evaluation of volcanic rocks in Yingcheng Formation by using abundant and complete geophysical logs from SK-2 east borehole. The log response analysis of volcanic rocks shows that the radioactivity and electric conductivity of tuffs are the strongest. Agglomeratic lavas have low density because of high porosity. The density of rhyolites is the highest and the electric conductivity is the weakest. Volcanic rocks of Yingcheng Formation along SK-2 east borehole consist of rhyolites, transitional tuffl lavas, agglomeratic lavas and a little tuffs by using cross plots and imaging models. A volcanic eruptive gap may exist, as evidenced by tuff with high GR, low RD and low DEN. Rhyolites are characterized by high alkali, high Si, low Fe and low clay mineral. T₂ analysis suggests that the rhyolites are favorable for carrying out long-term observations and fluid experiments. The results provide a reference of interpretation for subsequent volcanic rock in Huoshilin Formation and research of volcanic rocks in the whole basin.</p> 2019 1000-3657 10.12029/gc20190517 Geology in China 46 1174-1183 5 deep exploration engineering, SK-2 east borehole, volcanic rocks, log response characteristics, lithological evaluation /article/id/5fdc5ee1ed73f80a08606528 Jinhuan ZHAO Changchun Zou Wenshi Wang Xiaohuan ZHANG Yongyi Zhu Jinchang Zhang Hengchun Zhang Yujiao Ding Feng Lin Yuxing QIN Hai ZHOU Wenlong SUN article merz_magnetic_2019 The COSC-1 project drilled the several hundred meters thick basal shear zone of the Lower Seve nappe with mylonites in mica schists, amphibole schists and gneisses. In zones of high magnetic susceptibility from 1910 to 2450 m we studied magnetic and petrographic fabrics, and magnetic mineralogy. Borehole imaging allowed for geographic reorientation of the samples and offered the opportunity to study anisotropy of magnetic susceptibility (AMS) in relation to tectonic evolution of the Seve thrust. We measured AMS at room temperature, added low-temperature and field-dependent AMS for a subset of samples, and compared magnetic with petrographic fabrics. Triaxial and prolate magnetic fabrics with degree of anisotropy (P′) up to 3.2 together with abundant S-C fabrics and strain partitioning around porphyroclasts indicate dominant simple shear until 2300 m. Magnetite and ilmenohematite mimic the rock fabric due to fabric parallel alignment and/or magnetic interaction and either contribute to increase or decrease of P′, depending on the dominating rock fabric elements. Field-dependency of pyrrhotite and magnetite in kmax-direction further increases P′. Homogeneous and oblate petrographic and magnetic fabrics in the greenschist-grade overprinted rocks below 2300 m with subhorizontal kmax-kint-girdle distributions indicate dominant flattening. AMS depicts shear fabrics including magnetite and ilmenohematite, and is additionally increased by retrograde magnetite-rutile intergrowth in ilmenohematites. We interpret that shape and degree of AMS are controlled by (a) tectonic deformation and strain, (b) alteration and magnetic grain interaction, and (c) field-dependency of deformed pyrrhotite and/or magnetite. We observed that all petrographic and magnetic subfabrics are coaxial, and lineations are mainly E-W to SE-NW directed confirming the transport direction of the Caledonian allochthonous. From our microstructural and AMS results we suggest that thrusting of the Lower Seve unit commenced under simple shear conditions at higher metamorphic grades and subsequently switched to more pure shear under greenschist-grade conditions. 2019 jan en 0040-1951 10.1016/j.tecto.2018.12.018 Tectonophysics 751 212--228 Anisotropy of magnetic susceptibility (AMS), Crustal shear zone, Magnetic fabric, Seve nappe complex http://www.sciencedirect.com/science/article/pii/S0040195118304311 Lena Merz Bjarne S. G. Almqvist Jens C. Grimmer Agnes Kontny article Kent20194654 Article 2019 10.1029/2019GC008474 Geochemistry, Geophysics, Geosystems 20 4654 – 4664 11 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85074779240&doi=10.1029%2f2019GC008474&partnerID=40&md5=08e33200a86fa035ba2cf35625d8b207 Cited by: 28; All Open Access, Bronze Open Access Dennis V. Kent Paul E. Olsen Christopher Lepre Cornelia Rasmussen Roland Mundil George E. Gehrels Dominique Giesler Randall B. Irmis John W. Geissman William G. Parker article Türke201957 Surtsey, the youngest of the islands of Vestmannaeyjar, is an oceanic volcano created by explosive basaltic eruptions during 1963-1967 off the southern coast of Iceland. The subsurface deposits of the volcano were first sampled by a cored borehole in 1979. In summer 2017, three cored boreholes were drilled through the active hydrothermal system of the volcano by the International Continental Scientific Drilling Program (ICDP) SUSTAIN Expedition 5059. These cores are expected to provide the first glimpse of microbial life in very young and native basaltic tuff of the oceanic crust. To reduce the contamination of the subsurface environment, seawater circulating fluid was filtered and passed through two UV-sterilizing treatments. One of the boreholes has been equipped with a subsurface observatory dedicated in situ experiments for monitoring water-rock interactions and microbial processes in sterile, artificial basaltic glass and in olivine granules. With temperatures ranging from 25 to 125 °C, the subsurface observatory provides a precise geothermal window into an active hydrothermal system and thus represents an exceptional natural laboratory for studying fluid-rock-microbe interactions at different temperature regimes and facilitates experimental validation of active submarine microbial processes at the limit of functional life, about 121 °C. Comparisons with the 1979 and 2019 drill cores will provide time-lapse observations of hydrothermal processes over a 50-year timescale. Here, we present the technical design of the observatory and the incubation chamber experiments deployed from September 2017 to summer 2019. © Author(s) 2019. 2019 English 18168957 10.5194/sd-25-57-2019 Scientific Drilling 25 Copernicus GmbH 57-62 Department of Geosciences and MARUM, University of Bremen, Bremen, 28357, Germany; Department of Geology and Geophysics, University of Utah, Salt Lake City, UT 84102, United States; L3 Technologies Inc., Communications and Networked Systems, Salt Lake City, UT 84116, United States; DOSECC Exploration Services, Salt Lake City, UT 84101, United States; Nordvulk, Institute of Earth Sciences, University of Iceland, Reykjavík, Iceland; K.G. Jebsen Centre for Deep Sea Research, Department of Earth Science, University of Bergen, Bergen, Norway Basalt; Boreholes; Boring; Infill drilling; Microorganisms; Observatories; Silicate minerals; Volcanoes, Chamber experiments; Continental scientific drillings; Experimental validations; Hydrothermal process; Hydrothermal system; Natural laboratories; Subsurface environment; Water rock interactions, Core drilling https://www.scopus.com/inward/record.uri?eid=2-s2.0-85067240544&doi=10.5194%2fsd-25-57-2019&partnerID=40&md5=7ac5818ba44d0e9149da870e1ea34528 cited By 3 A. Türke M.D. Jackson W. Bach W.-A. Kahl B. Grzybowski B. Marshall M.T. Gudmundsson S.L. Jørgensen article Xu20191184 The completion depth of Well Songke 2 is 7108.88 m. At the time 38h after the well completion, the bottom hole temperature was 241℃. Three kinds of drilling fluids were investigated in laboratory according to the formation and temperature conditions, and they respectively are the potassium chloride-polysulfonate system which is resistant to temperature of 180℃, the polymer drilling fluid which is resistant to 230℃ and formate-polymer drilling fluid which is resistant to 250℃. The experimental data show that these drilling fluids have good high temperature stability and low HTHP filtration loss. Through detecting the quality of drilling fluid real time, the predicted problems could happen through over- temperature detection, which make indoor experiments to guide in- site maintenance in the project construction, ensure the stability performance at high temperature interval, and guarantee the coring operation smoothly. In addition, the drilling fluid of each system achieves a safe and smooth transition during the conversion, without any waste slurry, which greatly saves the cost. The logging and casing running before cementing could be successfully completed at one time, which further proves that the drilling fluid used has good high temperature stability. © 2019 Editorial Board of Geology in China. All rights reserved. Article 2019 Chinese 10003657 10.12029/gc20190518 Geology in China 46 Science Press 1184 – 1193 5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85107618279&doi=10.12029%2fgc20190518&partnerID=40&md5=e29fba26f4b18a703433fd0d2a047646 Cited by: 3 Jie Xu Yongyi Zhu Xiaoming Wu Wenshi Wang Hengchun Zhang Jia Yan Longlong Cao Lin Xu Linsheng Zhang Wenlong Zheng article Somma2019 Monitoring volcanic phenomena is a key question, for both volcanological research and for civil protection purposes. This is particularly true in densely populated volcanic areas, like the Campi Flegrei caldera, which includes part of the large city of Naples (Italy). Borehole monitoring of volcanoes is the most promising way to improve classical methods of surface monitoring, although not commonly applied yet. Fiber optics technology is the most practical and suitable way to operate in such high temperature and aggressive environmental conditions. In this paper, we describe a fiber optics Distributed Temperature Sensing (DTS) sensor, which has been designed to continuously measure temperature all along a 500 m. deep well drilled in the west side of Naples (Bagnoli area), lying in the Campi Flegrei volcanic area. It has then been installed as part of the international ‘Campi Flegrei Deep Drilling Project’, and is continuously operating, giving insight on the time variation of temperature along the whole borehole depth. Such continuous monitoring of temperature can in turn indicate volcanic processes linked to magma dynamics and/or to changes in the hydrothermal system. The developed monitoring system, working at bottom temperatures higher than 100 ◦ C, demonstrates the feasibility and effectiveness of using DTS for borehole volcanic monitoring. © 2019 by the authors. Licensee MDPI, Basel, Switzerland. Article 2019 English 14248220 10.3390/s19051009 Sensors (Switzerland) 19 MDPI AG 5 Boreholes; Boring; Environmental technology; Fiber optics; Fibers; Infill drilling; Temperature sensors; Volcanoes; Well drilling; Campi Flegrei; Continuous monitoring; Distributed temperature sensing; Environmental conditions; Hydrothermal system; Long term monitoring; Temperature calibration; Volcanic monitoring; Monitoring https://www.scopus.com/inward/record.uri?eid=2-s2.0-85062428559&doi=10.3390%2fs19051009&partnerID=40&md5=c306b05e2be37ea1777f67fedcde2433 Cited by: 10; All Open Access, Gold Open Access, Green Open Access Renato Somma Claudia Troise Luigi Zeni Aldo Minardo Alessandro Fedele Maurizio Mirabile Giuseppe De Natale article Siegert20192409 Impact melt-bearing clastic deposits (suevites) are one of the most important records of the impact cratering process. A deeper understanding of their composition and formation is therefore essential. This study focuses on impact melt particles in suevite at Ries, Germany. Textures and chemical evidence indicate that the suevite contains three melt types that originate from different shock levels in the target. The most abundant melt type (“melt type 1”) represents well-mixed whole-rock melting of crystalline basement and includes incompletely mixed mafic melt schlieren (“melt type 1 mafic”). Polymineralic melt type 2 comprises mixes between monomineralic melt types 3 and melt type 1. Melt types 2 and 3 are located within melt type 1 as small patches or schlieren but also isolated within the suevite matrix. The main melt type 1 is heterogeneous with respect to trace elements, varying geographically around the crater: in the western sector, it has lower values in trace elements, e.g., Ba, Zr, Th, and Ce, than in the eastern sector. The west–east zoning likely reflects the heterogeneous nature of crystalline basement target rocks with lower trace element contents, e.g., Ba, Zr, Th, and Ce, in the west compared to the east. The chemical zoning pattern of suevite melt type 1 indicates that mixing during ejection and emplacement occurred only on a local (hundreds of meters) scale. The incomplete larger scale mixing indicated by the preservation of these local chemical signatures, and schlieren corroborate the assumption that mixing, ejection, and quenching were very rapid, short-lived processes. © The Meteoritical Society, 2018. 2019 10.1111/maps.13210 Meteoritics and Planetary Science 54 2409-2447 Museum für Naturkunde, Leibniz-Institut für Evolutions- und Biodiversitätsforschung, Invalidenstraße 43, Berlin, 10115, Germany; Freie Universität Berlin, Institut für Geologische Wissenschaften, Malteserstraße 74-100, Berlin, 12249, Germany 10 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85057114107&doi=10.1111%2fmaps.13210&partnerID=40&md5=d8aed236041dd6a9b3dc39b7c67365db cited By 4 S. Siegert L. Hecht article Kriegerowski2019317 We develop an amplitude spectral ratio method for event couples from clustered earthquakes to estimate seismic wave attenuation (<span classCombining double low line"inline-formula"><i>Q</i>ĝ'1</span>) in the source volume. The method allows to study attenuation within the source region of earthquake swarms or aftershocks at depth, independent of wave path and attenuation between source region and surface station. We exploit the high-frequency slope of phase spectra using multitaper spectral estimates. The method is tested using simulated full wave-field seismograms affected by recorded noise and finite source rupture. The synthetic tests verify the approach and show that solutions are independent of focal mechanisms but also show that seismic noise may broaden the scatter of results. We apply the event couple spectral ratio method to northwest Bohemia, Czech Republic, a region characterized by the persistent occurrence of earthquake swarms in a confined source region at mid-crustal depth. Our method indicates a strong anomaly of high attenuation in the source region of the swarm with an averaged attenuation factor of <span classCombining double low line"inline-formula"><i>Q</i>p&lt;100</span>. The application to S phases fails due to scattered P-phase energy interfering with S phases. The <span classCombining double low line"inline-formula"><i>Q</i>p</span> anomaly supports the common hypothesis of highly fractured and fluid saturated rocks in the source region of the swarms in northwest Bohemia. However, high temperatures in a small volume around the swarms cannot be excluded to explain our observations. © 2019. This work is distributed under the Creative Commons Attribution 4.0 License. Article 2019 English 18699510 10.5194/se-10-317-2019 Solid Earth 10 Copernicus GmbH 317 – 328 1 Bohemia; Czech Republic; Transport properties; Amplitude spectral ratio; Attenuation factors; Earthquake swarms; High frequency HF; High temperature; Seismic wave attenuations; Spectral estimate; Spectral ratios; aftershock; earthquake swarm; seismic attenuation; seismic source; seismic wave; spectral analysis; Earthquake effects https://www.scopus.com/inward/record.uri?eid=2-s2.0-85061316174&doi=10.5194%2fse-10-317-2019&partnerID=40&md5=fa53aaab622308e907582c603bbebdf8 Cited by: 6; All Open Access, Gold Open Access, Green Open Access Marius Kriegerowski Simone Cesca Matthias Ohrnberger Torsten Dahm Frank Kruger article Oryan2019103 Numerical simulations emulating the formation of the Dead Sea Basin (DSB) infer that it could not have been formed as a pull-apart basin with a surface heat flow lower than 50[Formula presented]. However, previous measurements determined values of 32−40[Formula presented]. This contradiction is known as the “Dead Sea heat flow paradox”. Here we set to re-examine the “paradox” by analyzing heat flow data in boreholes drilled by the ICDP (International Continental Drilling Program) in the northern DSB. The boreholes and the extracted sediment cores offer a unique opportunity to re-measure the heat flow in the DSB and assess the “paradox”. Heat flow was determined by obtaining in situ temperature profiles from the boreholes and conducting 469 thermal conductivity measurements on the cores. The newly computed values are in agreement with those previously obtained for the DSB and fall below the threshold of 50[Formula presented]. Different explanations proposed to justify higher heat flow seem to fail leaving the “Dead Sea heat flow paradox” unresolved. Heat flow values and the sedimentation corrections determined in this research are consistent with the Ginzburg and Ben-Avraham subsurface model for the DSB, suggesting deeper sediment filling in the southern part of the basin. © 2019 Elsevier Ltd 2019 English 02773791 10.1016/j.quascirev.2019.02.016 Quaternary Science Reviews 210 Elsevier Ltd 103-112 Department of Geophysics, Tel Aviv University, Tel Aviv, 69978, Israel; Department of Geosciences, University of Bremen, Klagenfurter Strasse 2, Bremen, 28359, Germany; Department of Marine Geosciences, Leon H. Charney School of Marine Sciences, University of Haifa, Mount Carmel31905, Israel; Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences, Section Climate Dynamics and Landscape Evolution, Telegrafenberg, Potsdam, D-14473, Germany; Department of Earth Sciences, University of Geneva, Rue des Maraichers 13, Geneva, CH-1205, Switzerland Boreholes; Boring; Chloride minerals; Heat transfer; Infill drilling; Thermal conductivity, Dead sea basins; Deep drilling; In-situ temperature; International continental drilling program (ICDP); Salt diapirs; Subsurface model; Surface heat flow; Thermal conductivity measurements, Flow measuring instruments, borehole; correction; Deep Sea Drilling Project; diapir; heat flow; saline lake; sediment core; sedimentation; thermal conductivity, Calluna vulgaris https://www.scopus.com/inward/record.uri?eid=2-s2.0-85062811782&doi=10.1016%2fj.quascirev.2019.02.016&partnerID=40&md5=d0064288f898e235c22b5647c98b3a5e cited By 3 B. Oryan H. Villinger M. Lazar M.J. Schwab I. Neugebauer Z. Ben-Avraham article Valdez201917 Temperature is widely believed to act as a primary control on fault rheology, and therefore on the distribution of seismicity along plate boundary faults. However, there are few detailed measurements of the frictional strength and stability of natural fault gouges at elevated temperatures. Here, we report on a suite of shearing experiments designed to investigate the frictional behavior of fault rocks sampled from depths of 111.5–142.9 m along the Alpine Fault in New Zealand obtained by the International Continental Scientific Drilling Program (ICDP) Deep Fault Drilling Project (DFDP). We tested five samples from the DFDP-1B pilot hole: two hanging wall chloritic cataclasites, two footwall granitic cataclasites, and a fault gouge from the principal slip zone (PSZ-1). Each sample was sheared at a range of temperatures from 23 to 500 °C and at an effective normal stress of 80 MPa. The wall rock cataclasites exhibit an increase in the friction coefficient (μ) with temperature, from μ = 0.45–0.64 at 23 °C to μ = 0.87 at 500 °C. The PSZ-1 gouge exhibits lower friction coefficient values than the wall rock at temperatures ≤180 °C (μ = 0.35–0.46 vs 0.45–0.65), but comparable values (μ = 0.87–0.90) at 500 °C. The variation in frictional strength is accompanied by a transition from velocity-strengthening to velocity-weakening behavior at temperatures ≥180 °C for all materials. Extrapolation of the experimentally defined rheological critical stiffness of the fault material and the estimated in situ stiffness of the surrounding crust suggests upper and lower stability boundaries at ~1.8–2.5 km and ~8.5–8.8 km depth, respectively. The upper stability boundary is also consistent with the observed depth-frequency distribution of earthquakes. © 2019 2019 English 00401951 10.1016/j.tecto.2019.04.022 Tectonophysics 762 Elsevier B.V. 17-27 Department of Geosciences and Center for Geomechanics, Geofluids, and Geohazards, The Pennsylvania State University, Deike Building, University Park, PA 16802, United States; Center for Tectonophysics and Department of Geology and Geophysics, Texas A&M University, MS 3115, College Station, TX 77843, United States Earthquakes; Friction; Infill drilling; Stiffness; Temperature, Continental scientific drillings; Effective normal stress; Effects of temperature; Frequency distributions; Friction coefficients; High temperature; Scientific drilling; Stability boundaries, Faulting, cataclasite; drilling; earthquake; fault gouge; fault zone; friction; high temperature; rheology; stiffness; temperature effect, Alpine Fault Zone; New Zealand; South Island https://www.scopus.com/inward/record.uri?eid=2-s2.0-85064917047&doi=10.1016%2fj.tecto.2019.04.022&partnerID=40&md5=09e286cc123609a860697bc59cab7a30 cited By 5 II Valdez H. Kitajima D.M. Saffer article Yin2019644 2019 English 20959273 10.1016/j.scib.2019.03.020 Science Bulletin 64 Elsevier B.V. 644-646 Key Laboratory for Evolution of Past Life and Environment in Northeast Asia, Ministry of Education, Jilin University, Changchun, 130026, China; College of Earth Sciences, Jilin University, Changchun, 130026, China; Research Center of Palaeontology and Stratigraphy, Jilin University, Changchun, 130026, China; School of Petroleum Engineering, Chongqing University of Science and Technology, Chongqing, 401331, China 10 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85063965953&doi=10.1016%2fj.scib.2019.03.020&partnerID=40&md5=90837d1e8cd677c03e082790a1e6a090 cited By 12 Y. Yin Y. Gao P. Wang X. Qu H. Liu article Coldwell2019209 Potassium feldspar present in global mineral aerosol (<5%) plays a disproportionate role in modulating the microphysics of mixed-phase cloud. Via exceptional ice nucleation properties, it is capable of changing cloud properties and behaviour. Here we identify times of substantial and abrupt change in the global availability of potassium feldspar since 600 Ma. Normally, weathering and vegetation cover contribute to low availability, with clay dominating mineral aerosol. Periods of maximum availability are reasoned to follow the emplacement and remobilization of ejecta blankets from major meteorite impact events, before returning to background after some hundreds to thousands of years. We review the 44 largest confirmed craters and evaluate the potassium feldspar content of their target rocks, which range from c. 0 to >30%. By combining crater size and tectonic reconstructions, we are able to provide a quantitative and self-consistent assessment of changes to global potassium feldspar availability. Considerable differences in potassium feldspar availability following meteorite impact events are revealed. Different impact events generated dust containing different amounts of potassium feldspar. Differing levels of influence upon climate are hypothesized, and should now be tested by looking at stratigraphic records of these events to reveal the sensitivity of climate to different dust mineralogy. © 2018 The Author(s). 2019 10.1144/jgs2018-084 Journal of the Geological Society 176 209-224 Instituto Tecnológico y de Energías Renovables (ITER), Granadilla de Abona, Santa Cruz de Tenerife 38600, Spain; Instituto Volcanológico de Canarias (INVOLCAN), Calle Álvaro Martín Díaz 1, San Cristóbal de La Laguna, Santa Cruz de Tenerife 38320, Spain; School of Materials, University of Manchester, Manchester, M13 9PJ, United Kingdom; Research Complex at Harwell, Harwell Campus, Didcot, OX11 0FA, United Kingdom; School of Earth and Environment, University of Leeds, Leeds, LS2 9JT, United Kingdom 2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85063353451&doi=10.1144%2fjgs2018-084&partnerID=40&md5=72ba72c040095c8bca3dec26864cb7e2 cited By 1 B.C. Coldwell M.J. Pankhurst article Merey2019855 Gas hydrates are crystalline ice-like structures formed from water and gas molecules at high pressure and low temperature conditions. They are considered as near-future energy resources. Recently, there have been many drilling activities in gas hydrates in both permafrost regions (mainly Mallik wells, Canada; Ignik Sikumi #1 well, Alaska; Mount Elbert #1, Alaska) and marine sediments (the wells drilled in Gulf of Mexico and India drilling expeditions). In this study, it is aimed to evaluate and analyze logging-while drilling data (LWD) and other drilling data of these drilling activities. Initially, all drilling parameters (i.e. rate of penetration, weight on bit, torques, mud logs, etc.) of these wells were collected and drawn to see the change in parameters with depths. In order to indicate the changes in drilling parameters in the sediments containing gas hydrates, gas hydrate saturations were estimated from resistivity logs and NMR logs in this study. High resistivity log values and methane peaks in drilling fluid were good indicators of gas hydrate existence. During the drilling of permafrost formations and gas hydrates deposited in coarse sands as pore filling, the rate of penetration generally decreased. Differently, there was not almost any change in the rate of penetration during the drilling of fracture-filling gas hydrates within silts/clay in India. Borehole enlargements (washouts) were commonly seen in the wells drilled in marine sediments (Gulf of Mexico and Indian expeditions). However, this effect was minimum during the drilling of the wells in permafrost regions. This difference is due to the loose sediments in marine environment. Furthermore, gamma and density logs were seriously affected by washouts, mainly in marine sediments. It was observed that pore-filling gas hydrates affect the rate of penetration and keep the sediments stable because well collapses mainly occurred in the sediments without any gas hydrates. However, the temperature of drilling fluid should be close to the temperature of gas hydrate zones to reduce the effect of drilling on gas hydrate dissociation for the wells both in permafrost and marine sediments. In Gulf Mexico and Indian drilling expeditions, riser and wellhead equipment were not used. However, the usage of surface casing might decrease the risk of borehole collapses due to very loose sediments close to sea floor. Another important outcome of this study is that the pressure gradient follows hydrostatic pressure gradients according to the pressure analysis within gas hydrate stability zones of marine sediments. Finally, the analyses of drilling parameters revealed that drilling through gas hydrate bearing strata is not as risky as it might have been considered. The key is hidden in appropriate drilling design. © 2018 Elsevier B.V. 2019 English 09204105 10.1016/j.petrol.2018.08.079 Journal of Petroleum Science and Engineering 172 Elsevier B.V. 855-877 Batman University, Department of Petroleum and Natural Gas Engineering, Batman, Turkey Boring; Drilling; Drilling equipment; Drilling fluids; Electric logging; Filling; Gases; Hydration; Hydrostatic pressure; Infill drilling; Methane; Nuclear magnetic logging; Parameter estimation; Permafrost; Petroleum prospecting; Petroleum reservoir evaluation; Pressure gradient; Radioactivity logging; Renewable energy resources; Sediments; Submarine geology; Temperature; Well drilling, Borehole enlargements; Drilling of permafrost; Gas hydrate exploration wells; Gas hydrate saturations; Gas hydrate stability zones; Logging while drilling; Low temperature conditions; Methane hydrates, Gas hydrates, borehole; drilling; exploration; gas hydrate; gas well; marine sediment; methane; permafrost; pressure gradient, Atlantic Ocean; Gulf of Mexico; India https://www.scopus.com/inward/record.uri?eid=2-s2.0-85053061090&doi=10.1016%2fj.petrol.2018.08.079&partnerID=40&md5=4551dd54a7e624adfbe40984631f1f49 cited By 25 Ş. Merey article Lachmar2019 A geothermal exploration corehole was drilled to a total depth of 1821.5 m on the Mountain Home Air Force Base near Mountain Home, Idaho. The corehole was used to collect an unusually large amount of data, including uniaxial compressive stress (UCS) experiments on core samples, to evaluate the geothermal potential of the western Snake River Plain. In addition, unlike many exploration holes in this region, a fluid entry was encountered at 1745.3 m and flowed artesian to the surface. A maximum temperature of 149.4 °C was calculated for the entry. A temperature log run on the corehole from 3 to 1675 m is nearly linear with little variation. The average geothermal gradient is 73 °C/km, and the average heat flow between 200 and 1500 m is 102 ± 15 mW/m2. Chemical analyses of a sample from the fluid entry suggest that a significant proportion of the water is not meteoric. Five geothermometers show equilibrium temperature in the range of 133–157 °C. Furthermore, based on the unconfined UCS experiments on basalt core samples, a brittle unit was found to comprise the fractured reservoir that the geothermal water flows from, while an overlying ductile unit acts as a hydrothermal caprock. This implies that the reservoir/caprock pair may be a target for future exploration wells drilled to delineate the extent of the potential resource and the boundaries of the connected fracture network. © 2019, The Author(s). 2019 English 21959706 10.1186/s40517-019-0142-7 Geothermal Energy 7 SpringerOpen Department of Geosciences, Utah State University, Logan, UT 84322-4505, United States; Department of Earth Sciences, Southern Methodist University, P.O. Box 750395, Dallas, TX 75275, United States; DOSECC Exploration Services, LLC, 2057 Pioneer Road, Salt Lake City, UT 84104, United States; Department of Physics, University of Alberta, 4-181 CCIS, Edmonton, AB T6G 2E1, Canada; Department of Earth, Atmospheric, and Planetary Sciences, Purdue University, West Lafayette, IN 47907-2051, United States 1 Basalt; Chemical analysis; Core samples; Geothermal prospecting; Heat transfer; Infill drilling; Landforms; Thermal logging, Equilibrium temperatures; Geothermal exploration; Geothermal gradients; Geothermal potential; Geothermometers; Potential resources; Temperature log; Uniaxial compressive, Geothermal energy, basalt; compressive strength; experimental study; geothermal energy; geothermal power; geothermometry; heat flow; temperature effect; uniaxial strength, Idaho; Snake River Plain; United States, Calluna vulgaris https://www.scopus.com/inward/record.uri?eid=2-s2.0-85071910583&doi=10.1186%2fs40517-019-0142-7&partnerID=40&md5=b35ccfbd7f9245c5ebcb42d23da4af66 cited By 3 T.E. Lachmar T.G. Freeman J.A. Kessler J.F. Batir J.P. Evans D.L. Nielson J.W. Shervais X. Chen D.D. Blackwell article Ordoñez201932 Qualitative and quantitative changes of organic and carbonate carbon in sedimentary records are frequently used to reconstruct past environments, paleoproductivity and sediment provenance. Amongst the most commonly used proxies are Total Organic Carbon (TOC), Mineral Carbon (MinC), as well as Hydrogen (HI) and Oxygen Indices (OI) of organic matter (OM). Rock Eval pyrolysis enables the assessment of these quantitative and qualitative parameters with a single analysis. This is achieved through transient pyrolysis of the samples up to 650 °C followed by combustion up to 850 °C, with hydrocarbons, CO and CO2 measured during the thermal decomposition of both OM and carbonate minerals. Carbonate minerals with low thermal cracking temperatures, such as siderite (<400 °C), can induce significant matrix effects which bias the TOC, MinC and OI Rock-Eval parameters. Here we assess the applicability of End-Member Analysis (EMA) as a means of correcting Rock-Eval thermograms for siderite matrix effects. For this, we performed Rock-Eval pyrolysis on sideritic sediments of Lake Towuti (Indonesia). New thermal boundaries were constrained in Rock-Eval thermograms using EMA to limit siderite matrix effects and improve TOC, MinC and OI calculations. Our approach allowed us to: (1) evaluate the influence of siderite matrix effects on Rock-Eval thermograms; (2) properly exploit a Rock-Eval dataset to characterize the type and sources of OM in siderite-rich sediments and (3) identify the OM behind degradation and mineralization processes. The Rock-Eval dataset revealed sediments with a substantial amount of refractory OM, especially in those where TOC is high and HI characteristic of autochthonous biomass. These results, associated to alternative indices used to assess OM preservation, suggest that refractory OM is residually enriched following strong degradation of labile compounds. Finally, relatively labile and refractory organic fractions may be consumed in the formation of siderite during this sequential process of OM mineralization. © 2019 The Authors Article 2019 English 01466380 10.1016/j.orggeochem.2019.05.002 Organic Geochemistry 134 Elsevier Ltd 32 – 44 Greater Sunda Islands; Lake Towuti; Malili Lakes; South Sulawesi; Sulawesi; Sunda Isles; Biogeochemistry; Biological materials; Carbonate minerals; Carbonation; Iron ores; Lakes; Mineralogy; Organic carbon; Pyrolysis; Refractory materials; Sediments; Temperature measuring instruments; Thermoanalysis; Thermography (temperature measurement); Endmembers; Mineralization process; Qualitative parameters; Quantitative changes; Rock-Eval pyrolysis; Siderite; Total Organic Carbon; Tropical lakes; degradation; lacustrine deposit; lacustrine environment; mineralization; organic matter; paleoproductivity; provenance; pyrolysis; sediment chemistry; siderite; thermal decomposition; total organic carbon; Rocks https://www.scopus.com/inward/record.uri?eid=2-s2.0-85066755224&doi=10.1016%2fj.orggeochem.2019.05.002&partnerID=40&md5=ad1c6c2c3d863f52257d7ae994768b67 Cited by: 11; All Open Access, Green Open Access, Hybrid Gold Open Access Luis Ordoñez David Sebag Daniel Ariztegui Thierry Adatte James M. Russell Jens Kallmeyer Aurèle Vuillemin André Friese Sean A. Crowe Kohen W. Bauer Rachel Simister Cynthia Henny Sulung Nomosatryo Satria Bijaksana article Salge20192334 Drill core UNAM-7, obtained 126 km from the center of the Chicxulub impact structure, outside the crater rim, contains a sequence of 126.2 m suevitic, silicate melt-rich breccia on top of a silicate melt-poor breccia with anhydrite megablocks. Total reflection X-ray fluorescence analysis of altered silicate melt particles of the suevitic breccia shows high concentrations of Br, Sr, Cl, and Cu, which may indicate hydrothermal reaction with sea water. Scanning electron microscopy and energy-dispersive spectrometry reveal recrystallization of silicate components during annealing by superheated impact melt. At anhydrite clasts, recrystallization is represented by a sequence of comparatively large columnar, euhedral to subhedral anhydrite grains and smaller, polygonal to interlobate grains that progressively annealed deformation features. The presence of voids in anhydrite grains indicates SOx gas release during anhydrite decomposition. The silicate melt-poor breccia contains carbonate and sulfate particles cemented in a microcrystalline matrix. The matrix is dominated by anhydrite, dolomite, and calcite, with minor celestine and feldspars. Calcite-dominated inclusions in silicate melt with flow textures between recrystallized anhydrite and silicate melt suggest a former liquid state of these components. Vesicular and spherulitic calcite particles may indicate quenching of carbonate melts in the atmosphere at high cooling rates, and partial decomposition during decompression at postshock conditions. Dolomite particles with a recrystallization sequence of interlobate, polygonal, subhedral to euhedral microstructures may have been formed at a low cooling rate. We conclude that UNAM-7 provides evidence for solid-state recrystallization or melting and dissociation of sulfates during the Chicxulub impact event. The lack of anhydrite in the K-Pg ejecta deposits and rare presence of anhydrite in crater suevites may indicate that sulfates were completely dissociated at high temperature (T &gt; 1465 °C)—whereas ejecta deposited near the outer crater rim experienced postshock conditions that were less effective at dissociation. © The Trustees of the Natural History Museum, London, 2019. 2019 10.1111/maps.13283 Meteoritics and Planetary Science 54 2334-2356 Natural History Museum, Imaging and Analysis Centre, Cromwell Road, London, SW7 5BD, United Kingdom; Museum für Naturkunde, Leibniz-Institut für Evolutions- und Biodiversitätsforschung, Invalidenstrasse 43, Berlin, 10115, Germany; Bruker Nano GmbH, Am Studio, Berlin, 12489, Germany; Dipertimento Disputer, Università G. d'Annunzio, Chieti, 66100, Italy; Institut für Geologische Wissenschaften, Freie Universität Berlin, Malteserstraße 74-100, Berlin, 12249, Germany; Laboratory of Geochronology, Instituto de Geociências, Universidade de Brasília, Brasília, DF 70910 900, Brazil 10 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85063860385&doi=10.1111%2fmaps.13283&partnerID=40&md5=457457f70366179870d7ce3fadba827b cited By 3 T. Salge H. Stosnach G. Rosatelli L. Hecht W.U. Reimold article Manzi201989 Article 2019 10.3997/1365-2397.n0050 First Break 37 89 – 96 8 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85072603317&doi=10.3997%2f1365-2397.n0050&partnerID=40&md5=2ccfb03198ed221ea3ad5ce7a6265aaf Cited by: 19 Musa Manzi Alireza Malehmir Raymond Durrheim article basin2019fine 2019 Songliao Basin Shuo LIU You-feng GAO Yong-kang YIN Hai-bo LIU Hong-hao LI Pu-jun WANG article Fu20191349 In order to reveal the fine structure of the lithosphere adjacent to Well SK-2, a deep seismic reflection profile crossing Well SK-2 was laid out in the Songliao Basin (SB), with the trend north to south. Data acquisition was featured in the shooting technique of multi-scale explosive source and data reception by large offset with smaller trace distance in key area. Besides, processing flow of high fidelity and amplitude-preservation was undertaken to get the pre-stack migrated seismic reflection profile with high resolution and high signal-to-noise ratio. As the result, the profile shows strong reflections from settled layers alternate with and weak reflections of igneous rock beneath T4 reflector, and two residuals of upper Paleozoic stratums are distinguished out, one is beneath Well SK-2 (TWT, 3.5~4 s), the other is beneath the Renmin-Yong'an Terrace (CDP, 3500~4500, TWT, 3.5~4 s). Some paralleled seismic patterns dipping north can be observed in the middle and lower crust, as well as some strong but short lenticular reflectors are observed beneath Zhonghe Fault Depression, and the overall contour of these lenticular reflectors is like a mushroom cloud, we interpret this phenomenon as the hot material from downward in the lithosphere extension environment. The Moho in the north part shows strong near-horizontal continuous reflection, while the Moho in the Xujiaweizi Fault Depression in the south shows weak reflection. Three types of upper mantle reflections are distinguished on the deep seismic profile, including inclined mantle reflections, near-horizontal mantle reflections and super-deep reflections in the mantle. It is inferred that they are the early subduction relics, bottom of early thickened crust and the present lithosphere-asthenosphere boundary (LAB). Based on the latest results of deep seismic profile detecting crossing Well SK-2, this paper study structure features preserved in the lithosphere of Songnen Massif with tectonic superposition of Palo-Asia Ocean regime, Mongol-Okhotsk regime and Palo-Pacific regime, thus providing a new perspective for the discussion of the formation cause, tectonic background and dynamic factors of Songliao Basin. © 2019, Science Press. All right reserved. 2019 Chinese 00015733 10.6038/cjg2019M0370 Acta Geophysica Sinica 62 Science Press 1349-1361 College of Geo-exploration Science and Technology, Jilin University, Changchun, 130026, China; Chinese Academy of Geological Sciences, Beijing, 100037, China; School of Earth Science and Engineering, Sun Yat-Sen University, Guangzhou, 510275, China; Key Laboratory of Deep-Earth Dynamics of Ministry of Natural Resources, Institute of Geology, Chinese Academy of Geological Sciences, Beijing, 100037, China 4 Atomic physics; Data acquisition; Faulting; Igneous rocks; Reflection; Seismic waves; Seismology; Signal to noise ratio, Deep seismic reflection profiles; Deep seismic reflections; Lithosphere-asthenosphere boundary; Mantle reflections; Moho; Seismic reflection profiles; Songliao basin; Xujiaweizi Fault Depression, Structural geology, fault zone; igneous rock; lithospheric structure; mantle structure; Moho; Paleozoic; seismic reflection; signal-to-noise ratio; subduction; upper mantle, China; Fujian; Heilongjiang; Mongol-Okhotsk Fold Belt; Songliao Basin; Xujiaweizi; Yongan, Basidiomycota https://www.scopus.com/inward/record.uri?eid=2-s2.0-85066424100&doi=10.6038%2fcjg2019M0370&partnerID=40&md5=effa11e8d062e1ce1ba122c6c688b9bd cited By 7 W. Fu H. Hou R. Gao C. Liu J. Yang R. Guo article Vuillemin2019540 Ferruginous conditions prevailed in the world's deep oceans during the Archean and Proterozoic Eons. Sedimentary iron formations deposited at that time may provide an important record of environmental conditions, yet linking the chemistry and mineralogy of these sedimentary rocks to depositional conditions remains a challenge due to a dearth of information about the processes by which minerals form in analogous modern environments. We identified siderites in ferruginous Lake Towuti, Indonesia, which we characterized using high-resolution microscopic and spectroscopic imaging combined with microchemical and geochemical analyses. We infer early diagenetic growth of siderite crystals as a response to sedimentary organic carbon degradation and the accumulation of dissolved inorganic carbon in pore waters. We suggest that siderite formation proceeds through syntaxial growth on preexisting siderite crystals, or possibly through aging of precursor carbonate green rust. Crystal growth ultimately leads to spar-sized ( > 50 μm) mosaic single siderite crystals that form twins, bundles, and spheroidal aggregates during burial. Early-formed carbonate was detectable through microchemical zonation and the possible presence of residual phases trapped in siderite interstices. This suggests that such microchemical zonation and mineral inclusions may be used to infer siderite growth histories in ancient sedimentary rocks including sedimentary iron formations. © 2019 Geological Society of America. Article 2019 English 00917613 10.1130/G46100.1 Geology 47 Geological Society of America 540 – 544 6 Greater Sunda Islands; Lake Towuti; Malili Lakes; South Sulawesi; Sulawesi; Sunda Isles; Analytical geochemistry; Iron; Iron ores; Organic carbon; Sedimentology; Depositional condition; Diagenetic growth; Dissolved inorganic carbon; Environmental conditions; Geochemical analysis; Mineral inclusions; Proterozoic eons; Spectroscopic imaging; diagenesis; dissolved inorganic carbon; formation mechanism; iron; mineralogy; organic carbon; porewater; sediment analysis; sediment chemistry; sedimentary rock; siderite; Sedimentary rocks https://www.scopus.com/inward/record.uri?eid=2-s2.0-85066434739&doi=10.1130%2fG46100.1&partnerID=40&md5=4eff5b8101f8d25ca5b2040986aa53d6 Cited by: 27; All Open Access, Green Open Access, Hybrid Gold Open Access Aurèle Vuillemin Helga Kemnitz André Friese Kohen W. Bauer Rachel Simister Sulung Nomosatryo Luis Ordoñez Daniel Ariztegui Cynthia Henny Sean A. Crowe Liane G. Benning Jens Kallmeyer James M. Russell Satria Bijaksana The Towuti Drilling Project Science Team conference Collett2019 Since their initial discovery in the 1960's, gas hydrates have been considered to be an important potential source of unconventional natural gas. Significant progress has been made relative to our understanding of the geologic and engineering controls on the ultimate energy potential of gas hydrate; however, more work is required to realize the promise of gas hydrates as a future energy source. Gas hydrates have been encountered, recovered or inferred to exist in numerous sedimentary basins in Arctic permafrost settings, regions of alpine permafrost, marine sediments of outer continental margins and in deep lakes. Despite the great abundance of potential gas hydrate resources in the world, a large portion of these resources reside in clay-rich sediments and fracture dominated reservoir systems, and are not generally considered producible with existing technology, but may have future potential with the emergence of new technologies. For a large portion of the world, gas hydrate in sand reservoirs have become a viable production target and the focus of the first production testing efforts. Production tests in Arctic Canada (Mackenzie Delta) and Alaska have shown that gas can be produced from highly-concentrated gas hydrate accumulations in coarse-grained (i.e., sand rich) reservoir systems with conventional production technologies. Production can be achieved through the depressurization method and by more complex methods such as molecular substitution (e.g., CO2-CH4 exchange). In 2013, the gas hydrate production test was conducted in a marine setting in the offshore of Japan. An additional test was conducted in Japan in 2017 to further evaluate alternative well completion technologies. Also in 2018, China initiated a 60-day gas hydrate production test in the Shenhu region of the South China Sea. This report reviews the results of gas hydrate engineering and production testing studies associated with the Mallik, Mount Elbert, and Iġnik Sikumi projects in northern Canada and Alaska. The results of the marine gas hydrate producing testing efforts in the Nankai Trough (Japan) and in the South China Sea (China) are also summarized. © 2019 Offshore Technology Conference. All rights reserved. 2019 English 9781613996416 01603663 10.4043/29516-ms Proceedings of the Annual Offshore Technology Conference 2019-May Offshore Technology Conference U.S. Geological Survey, United States Gas engineering; Gases; Hydration; Offshore oil well production; Offshore technology; Permafrost; Renewable energy resources; Submarine geology; Well completion, Completion technology; Depressurization methods; Engineering controls; Gas-hydrate production; Hydrate accumulations; Molecular substitution; Production technology; Unconventional natural gas, Gas hydrates https://www.scopus.com/inward/record.uri?eid=2-s2.0-85066611678&doi=10.4043%2f29516-ms&partnerID=40&md5=178f52768e10f7715cfb25f8b98c8b62 cited By 20 T.S. Collett article Drabon2019849 Article 2019 10.2110/jsr.2019.46 Journal of Sedimentary Research 89 849 – 874 9 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85075675350&doi=10.2110%2fjsr.2019.46&partnerID=40&md5=a10534e8d763733e0f7a950681f8b3ce Cited by: 19 Nadja Drabon Christoph E. Heubeck Donald R. Lowe incollection 10.1130/2018.2537 {The late Eocene Chesapeake Bay impact structure was formed in a multilayered target of seawater underlain sequentially by a sediment layer and a rock layer in a continental-shelf environment. Impact effects in the “brim” (annular trough) surrounding and adjacent to the transient crater, between the transient crater rim and the outer margin, primarily were limited to the target-sediment layer. Analysis of published and new lithostratigraphic, biostratigraphic, sedimentologic, petrologic, and mineralogic studies of three core holes, and published studies of a fourth core hole, provided information for the interpretation of the impact processes, their interactions and relative timing, their resulting products, and sedimentation in the brim.Most studies of marine impact-crater materials have focused on those found in the central crater. There are relatively few large, complex marine craters, of which most display a wide brim around the central crater. However, most have been studied using minimal data sets. The large number of core holes and seismic profiles available for study of the Chesapeake Bay impact structure presents a special opportunity for research.The physical and chronologic records supplied by study of the sediment and rock cores of the Chesapeake Bay impact indicate that the effects of the initial, short-lived contact and compression and excavation stages of the impact event primarily were limited to the transient crater. Only secondary effects of these processes are evident in the brim. The preserved record of the brim was created primarily in the subsequent modification stage.In the brim, the records of early impact processes (e.g., outgoing tsunamis, overturned flap collapse) were modified or removed by later processes. Transported and rotated, large and small clasts of target sediments, and intervals of fluidized sands indicate that seismic shaking fractured and partially fluidized the Cretaceous and Paleogene target sediments, which led to their inward transport by collapse and lateral spreading toward the transient crater. The succeeding inward seawater-resurge flow quickly overtook and interacted with the lateral spreading, further facilitating sediment transport across the brim and into the transient crater. Variations in the cohesion and relative depth of the target sediments controlled their degree of disaggregation and redistribution during these events. Melt clasts and shocked and unshocked rock clasts in the resurge sediments indicate fallout from the ejecta curtain and plume.Basal parautochthonous remnant sections of target Cretaceous sediments in the brim thin toward the collapsed transient crater. Overlying seawater-resurge deposits consist primarily of diamictons that vary laterally in thickness, and vertically and laterally in maximum grain size. After cessation of resurge flow and re-establishment of pre-impact sea level, sandy sediment gravity flows moved from the margin to the center of the partially filled impact structure (shelf basin). The uppermost unit consists of stratified sediments deposited from suspension. Postimpact clayey silts cap the crater fill and record the return to shelf sedimentation at atypically large paleodepths within the shelf basin.An unresolved question involves a section of gravel and sand that overlies Neoproterozoic granite in the inner part of the brim in one core hole. This section may represent previously unrecognized, now parautochthonous Cretaceous sediments lying nonconformably above basement granite, or it may represent target sediments that were moved significant distances by lateral spreading above basement rocks or above a granite megaclast from the overturned flap.The Chesapeake Bay impact structure is perhaps the best documented example of the small group of multilayer, marine-target impacts formed in continental shelves or beneath epeiric seas. The restriction of most impact effects to the target-sediment layer in the area outside the transient cavity, herein called the brim, and the presence of seawater-resurge sediments are characteristic features of this group. Other examples include the Montagnais (offshore Nova Scotia, Canada) and Mjølnir (offshore Norway) impact structures.} 2018 11 9780813725376 10.1130/2018.2537 {Chesapeake Bay Impact Structure—Development of “Brim” Sedimentation in a Multilayered Marine Target} Geological Society of America https://doi.org/10.1130/2018.2537 Henning Dypvik Gregory S. Gohn Lucy E. Edwards Jr. Horton David S. Powars Ronald J. Litwin article Baranyi2018775 Fossil plant assemblages including spores and pollen grains provide useful information on past ecosystems and the response of terrestrial biotas to various environmental perturbations. New quantitative palynological data from the Chinle Formation of the American Southwest suggest that a floral turnover occurred in the middle Norian (between 217 and 213 Ma). Analysis of plant communities reveals that this turnover was followed by a complete reorganization of the riparian vegetation, driven by changes in fluvial styles and the tectonic regime of the basin, as well as a gradual transition toward a more arid climate. Marked increases in Klausipollenites gouldii, Patinasporites spp., and Froelichsporites traversei are probable indicators of environmental stress, such as increased aridity, perturbations of atmospheric pCO2, acid rain, and atmospheric aerosol accumulation due to volcanism in connection with the Pangean rifting and uplift of the Cordilleran arc. Comparison of the vegetation turnover with younger assemblages from the Chinle Formation in New Mexico revealed similar floral turnover patterns, suggesting two distinct drier periods as a result of multiple climatic oscillations. The climate-induced floral turnover may have contributed to the vertebrate faunal turnover as the loss of wetland habitat space and an increase in xerophytic plants may have dwindled the supply of palatable vegetation for herbivores. The onset of the floral turnover in Arizona roughly corresponds to the Manicouagan impact event, but a direct causal link is still speculative. © 2017 Geological Society of America. 2018 English 00167606 10.1130/B31673.1 Bulletin of the Geological Society of America 130 Geological Society of America 775-795 Department of Geosciences, University of Oslo, P.O. Box 1047, Blindern, Oslo, 0316, Norway; Lamont-Doherty Earth Observatory, 61 Route 9W, P.O. Box 1000, Palisades, NY 10964-8000, United States; Division of Resource Management, Petrified Forest National Park, 1 Park Road, #2217, Petrified Forest, AZ 86028, United States 5-6 Acid rain; Atmospheric aerosols; Ecosystems, Climatic oscillations; Environmental change; Environmental perturbations; Environmental stress; Gradual transition; Plant communities; Riparian vegetation; Vegetation history, Vegetation, aridity; environmental change; Norian; paleoclimate; paleoenvironment; paleogeography; palynology; plant community; vegetation history, Arizona; Petrified Forest National Park; United States, Klausipollenites; Vertebrata https://www.scopus.com/inward/record.uri?eid=2-s2.0-85041313171&doi=10.1130%2fB31673.1&partnerID=40&md5=79f3b4c5b6624fbc81c8ea54aee80b50 cited By 25 V. Baranyi T. Reichgelt P.E. Olsen W.G. Parker W.M. Kürschner article Weber2018393 We summarize and then build on the three decades of geological mapping and analyses done by Ray Gutschick at the Newton County (Kentland) quarry. We present our own new data and ideas on the kinematics and significance of radial faults, shock metamorphism, petrography and diagenesis of impact breccia dikes, impactite geochemistry, and a preliminary new paleomagnetically determined Jurassic age for the crater. We list and describe the stops for this field excursion. © 2018 The Geological Society of America. 2018 10.1130/2018.0051(15) GSA Field Guides 51 393-407 Department of Geology, Grand Valley State University, Allendale, MI 49401, United States; School of Geology and Geophysics, University of Oklahoma, Norman, OK, United States; Department of Lithospheric Research, University of Vienna, Althanstrasse 14, Vienna, A-1090, Austria; Natural History Museum, Burgring 7, Vienna, A-1010, Austria; Department of Geology and Geophysics, Texas A and M University, College Station, TX 77843-3115, United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-85062097963&doi=10.1130%2f2018.0051%2815%29&partnerID=40&md5=e827ffa77e5d6305a7e7fe11b0c19110 cited By 0 J.C. Weber R. Douglas Elmore C. Hamilton A. Alder C. Koeberl M. Pope article Colón20181 We present new high-precision CA-ID-TIMS and in situ U–Pb ages together with Hf and O isotopic analyses (analyses performed all on the same grains) from four tuffs from the 15−10 Ma Bruneau–Jarbidge center of the Snake River Plain and from three rhyolitic units from the Kimberly borehole in the neighboring 10−6 Ma Twin Falls volcanic center. We find significant intrasample diversity in zircon ages (ranges of up to 3 Myr) and in δ18 O (ranges of up to 6‰) and εHf (ranges of up to 24 ε units) values. Zircon rims are also more homogeneous than the associated cores, and we show that zircon rim growth occurs faster than the resolution of in situ dating techniques. CA-ID-TIMS dating of a subset of zircon grains from the Twin Falls samples reveals complex crystallization histories spanning 104 –106 years prior to some eruptions, suggesting that magma genesis was characterized by the cyclic remelting of buried volcanic rocks and intrusions associated with previous magmatic episodes. Age-dependent trends in zircon isotopic compositions show that rhyolite production in the Yellowstone hotspot track is driven by the mixing of mantle-derived melts (normal δ18 O and εHf) and a combination of Precambrian basement rock (normal δ18 O and εHf down to − 60) and shallow Mesozoic and Cenozoic age rocks, some of which are hydrothermally altered (to low δ18 O values) by earlier stages of Snake River Plain magmatism. These crustal melts hybridize with juvenile basalts and rhyolites to produce the erupted rhyolites. We also observe that the Precambrian basement rock is only an important component in the erupted magmas in the first eruption at each caldera center, suggesting that the accumulation of new intrusions quickly builds an upper crustal intrusive body which is isolated from the Precambrian basement and evolves towards more isotopically juvenile and lower-δ18 O compositions over time. © Springer-Verlag GmbH Germany, part of Springer Nature 2018. 2018 English 00107999 10.1007/s00410-017-1437-y Contributions to Mineralogy and Petrology 173 Springer Science and Business Media Deutschland GmbH 1-18 University of Oregon, Eugene, OR, United States; Department of Earth Sciences, Institute of Geochemistry and Petrology, ETH Zürich, Zurich, Switzerland; Brigham Young University, Provo, UT, United States; University of Alberta, Edmonton, AB, Canada 2 geochronology; hafnium; isotopic analysis; magma; oxygen isotope; rhyolite; tuff; uranium-lead dating; zircon, Idaho; Snake River Plain; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-85044293111&doi=10.1007%2fs00410-017-1437-y&partnerID=40&md5=ea35dcee789b198e52d51cab12785f64 cited By 20 D.P. Colón I.N. Bindeman J.-F. Wotzlaw E.H. Christiansen R.A. Stern article Sinopoli2018177 In this article, we present new, high-resolution, pollen results obtained from the DEEP site sequence recovered from Lake Ohrid (Albania/FYROM) for the Last Interglacial Complex (LIC), corresponding to Marine Isotope Stage 5 (MIS 5) of the marine isotope stratigraphy. LIC covers the period between 130 and 70 ka and includes the Eemian (Last Interglacial, LI) and the succession of stadial and interstadial phases of the Early Last Glacial. During the LIC, the pollen record shows an alternation of periods characterized by forest and open vegetation, clearly resembling the well-known vegetational succession of other European records. Our results reveal three key phases for the LI: a first period (128-125 ka) with a rapid increase in temperature and precipitation, a central phase (125–118.5 ka) characterized by a slight cooling, and a late phase (118.5–112 ka), with a decline both in temperatures and precipitation. Besides the LI, we identify four more forested periods dominated by mesophilous trees and intercalated by colder and drier steppe phases, during which, however, most arboreal taxa never disappear. During the Early Last Glacial we also identify several abrupt events that can be correlated to the succession of cold events recorded in the Greenland ice core records, associated to a weakening of the North Atlantic Meridional Overturning Circulation. The new high-resolution record indicates that Lake Ohrid is an important site to understand the response of vegetation to fluctuations in regional moisture availability and temperature changes, and thus provides new evidence for the connection between the Mediterranean Region and Northern Hemisphere climate oscillations. © 2017 Elsevier Ltd 2018 English 02773791 10.1016/j.quascirev.2017.11.013 Quaternary Science Reviews 180 Elsevier Ltd 177-192 Department of Earth Sciences, Sapienza University of Rome, Piazzale Aldo Moro 5, Roma, 00185, Italy; Department of Environmental Biology, Sapienza University of Rome, Piazzale Aldo Moro 5, Roma, 00185, Italy; ISEM, University of Montpellier, CNRS, IRD, EPHE, 163 Rue Auguste Broussonnet, Montpellier, 34090, France; Department of Earth Sciences, University of Pisa, Via S. Maria 53, Pisa, 56126, Italy; Institute of Earth Sciences and Earth Resources, National Research Council, IGG-CNR, Via Moruzzi 1, Pisa, 56126, Italy; Institute of Geology and Mineralogy, University of Cologne, Zülpicher Str. 49a, Cologne, 50674, Germany; Wollongong Isotope Geochronology Laboratory, School of Earth and Environmental Sciences, University of Wollongong, Wollongong, NSW 2522, Australia Climatology; Convolution; Forestry; Glacial geology; Isotopes; Stratigraphy; Vegetation, Albania; Lake Ohrid; Last interglacial; Palaeoclimatology; Palynology; Vegetation change, Lakes, cooling; Eemian; forest-steppe; ice core; interstadial; Last Glacial; Last Interglacial; marine isotope stage; meridional circulation; Northern Hemisphere; paleoclimate; paleoenvironment; paleotemperature; palynology; pollen; precipitation (climatology); vegetation dynamics, Albania; Arctic; Atlantic Ocean; Atlantic Ocean (North); Greenland; Greenland Ice Sheet; Lake Ohrid; Mediterranean Region https://www.scopus.com/inward/record.uri?eid=2-s2.0-85036456621&doi=10.1016%2fj.quascirev.2017.11.013&partnerID=40&md5=d43728001bc8a47dd0ec29ed7e4c5238 cited By 32 G. Sinopoli A. Masi E. Regattieri B. Wagner A. Francke O. Peyron L. Sadori article Kontny2018921 We studied the effect of 973 K heating in argon atmosphere on the magnetic and structural properties of a magnetite-bearing ore, which was previously exposed to laboratory shock waves between 5 and 30 GPa. For this purpose magnetic properties were studied using temperature-dependent magnetic susceptibility, magnetic hysteresis and low-temperature saturation isothermal remanent magnetization. Structural properties of magnetite were analyzed using X-ray diffraction, high-resolution scanning electron microscopy and synchrotron-assisted X-ray absorption spectroscopy. The shock-induced changes include magnetic domain size reduction due to brittle and ductile deformation features and an increase in Verwey transition temperature due to lattice distortion. After heating, the crystal lattice is relaxed and apparent crystallite size is increased suggesting a recovery of lattice defects documented by a mosaic recrystallization texture. The structural changes correlate with modifications in magnetic domain state recorded by temperature-dependent magnetic susceptibility, hysteresis properties and low-temperature saturation isothermal remanent magnetization. These alterations in both, magnetic and structural properties of magnetite can be used to assess impact-related magnetic anomalies in impact structures with a high temperature overprint. © 2018. American Geophysical Union. All Rights Reserved. 2018 10.1002/2017GC007331 Geochemistry, Geophysics, Geosystems 19 921-931 Institute of Applied Geosciences, Karlsruhe Institute of Technology, Karlsruhe, Germany; SLAC National Accelerator Laboratory, Stanford Synchrotron Radiation Lightsource (SSRL), Menlo Park, CA, United States; Synchrotron Radiation Facility ANKA, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany 3 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85044219734&doi=10.1002%2f2017GC007331&partnerID=40&md5=8de02fa1cf1a17cf1390cc580d43ec72 cited By 9 A. Kontny B. Reznik A. Boubnov J. Göttlicher R. Steininger article Hughes201889 Physical and compositional measurements are made at the ~ 7 km-long (~ 2200 years B.P.) Kings Bowl basaltic fissure system and surrounding lava field in order to further understand the interaction of fissure-fed lavas with phreatic explosive events. These assessments are intended to elucidate the cause and potential for hazards associated with phreatic phases that occur during basaltic fissure eruptions. In the present paper we focus on a general understanding of the geological history of the site. We utilize geospatial analysis of lava surfaces, lithologic and geochemical signatures of lava flows and explosively ejected blocks, and surveys via ground observation and remote sensing. Lithologic and geochemical signatures readily distinguish between Kings Bowl and underlying pre-Kings Bowl lava flows, both of which comprise phreatic ejecta from the Kings Bowl fissure. These basalt types, as well as neighboring lava flows from the contemporaneous Wapi lava field and the older Inferno Chasm vent and outflow channel, fall compositionally within the framework of eastern Snake River Plain olivine tholeiites. Total volume of lava in the Kings Bowl field is estimated to be ~ 0.0125 km3, compared to a previous estimate of 0.005 km3. The main (central) lava lake lost a total of ~ 0.0018 km3 of magma by either drain-back into the fissure system or breakout flows from breached levees. Phreatic explosions along the Kings Bowl fissure system occurred after magma supply was cut off, leading to fissure evacuation, and were triggered by magma withdrawal. The fissure system produced multiple phreatic explosions and the main pit is accompanied by others that occur as subordinate pits and linear blast corridors along the fissure. The drop in magma supply and the concomitant influx of groundwater were necessary processes that led to the formation of Kings Bowl and other pits along the fissure. A conceptual model is presented that has relevance to the broader range of low-volume, monogenetic basaltic fissure eruptions on Earth, the Moon and other planetary bodies. © 2018 Elsevier B.V. 2018 English 03770273 10.1016/j.jvolgeores.2018.01.001 Journal of Volcanology and Geothermal Research 351 Elsevier B.V. 89-104 Department of Geosciences, Idaho State University, 921 South 8th Avenue, Stop 8072, Pocatello, ID 83209, United States; NASA Ames Research Center, Mountain View, CA 94035, United States; Bay Area Environmental Research Institute, Petaluma, CA 94952, United States; NASA Goddard Space Flight Center, Geology, Geophysics and Geochemistry Lab, Greenbelt, MD 20771, United States; Department of Geological Sciences, Brigham Young University, Provo, UT 84602, United States; Mars Space Flight Facility, Arizona State University, Tempe, AZ 85287, United States Basalt; Geochemical surveys; Geochemistry; Groundwater; Lakes; Moon; Remote sensing; Silicate minerals, Fissure eruptions; Geo-spatial analysis; Geochemical signatures; Geological history; Ground observations; Phreatic explosions; Pit craters; Snake river plains, Explosions, basalt; crater; fissure; lava flow; magma; volcanic eruption, Idaho; Snake River Plain; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-85044639442&doi=10.1016%2fj.jvolgeores.2018.01.001&partnerID=40&md5=fed97740432e480174b8c49a860e1352 cited By 8 S.S. Hughes S.E. Kobs Nawotniak D.W.G. Sears C. Borg W.B. Garry E.H. Christiansen C.W. Haberle D.S.S. Lim J.L. Heldmann article sadori2018pdot data set 2018 10.1594/PANGAEA.892362 PANGAEA PANGAEA https://doi.org/10.1594/PANGAEA.892362 Laura Sadori Andreas Koutsodendris Konstantinos Panagiotopoulos Alessia Masi Adele Bertini Nathalie Combourieu-Nebout Alexander Francke Katerina Kouli Ilias Kousis S\'{e}bastien Joannin Anna Maria Mercuri Odile Peyron Paola Torri Bernd Wagner Giovanni Zanchetta Gaia Sinopoli Timme H Donders article Faulkner2018226 The strength of fault zones is strongly dependent on pore fluid pressures within them. Moreover, transient changes in pore fluid pressure can lead to a variety of slip behavior from creep to unstable slip manifested as earthquakes or slow slip events. The frictional properties of low-permeability fault gouge in nature and experiment can be affected by pore fluid pressure development through compaction within the gouge layer, even when the boundaries are drained. Here the conditions under which significant pore fluid pressures develop are analyzed analytically, numerically, and experimentally. Friction experiments on low-permeability fault gouge at different sliding velocities show progressive weakening as slip rate is increased, indicating that faster experiments are incapable of draining the pore fluid pressure produced by compaction. Experiments are used to constrain the evolution of the permeability and pore volume needed for numerical modeling of pore fluid pressure build up. The numerical results are in good agreement with the experiments, indicating that the principal physical processes have been considered. The model is used to analyze the effect of pore fluid pressure transients on the determination of the frictional properties, illustrating that intrinsic velocity-strengthening behavior can appear velocity weakening if pore fluid pressure is not given sufficient time to equilibrate. The results illustrate that care must be taken when measuring experimentally the frictional characteristics of low-permeability fault gouge. The contribution of compaction-induced pore fluid pressurization leading to weakening of natural faults is considered. Cyclic pressurization of pore fluid within fault gouge during successive earthquakes on larger faults may reset porosity and hence the capacity for compaction weakening. ©2017. The Authors. 2018 English 21699313 10.1002/2017JB015130 Journal of Geophysical Research: Solid Earth 123 Blackwell Publishing Ltd 226-241 Rock Deformation Laboratory, Department of Earth, Ocean and Ecological Sciences, University of Liverpool, Liverpool, United Kingdom; Departamento de Geología y CEACTierra, Unidad Asociada IACT (CSIC-UGR), Universidad de Jaén, Jaén, Spain; Now at School of Geography, Environment, and Earth Sciences, Victoria University of Wellington, Wellington, New Zealand 1 deformation mechanism; experimental study; fault gouge; fault zone; fluid pressure; friction; permeability; pore pressure; slip rate; theoretical study https://www.scopus.com/inward/record.uri?eid=2-s2.0-85040719553&doi=10.1002%2f2017JB015130&partnerID=40&md5=6a58855ab44d145af6485bb85d7f16b0 cited By 70 D.R. Faulkner C. Sanchez-Roa C. Boulton S.A.M. Hartog article Spanbauer201889 High levels of biodiversity and endemism in ancient lakes have motivated research on evolutionary processes in these systems. Drill-core records from Lake Titicaca (Bolivia, Peru), an ancient lake in the high-elevation Altiplano, record the history of climate, landscape dynamics, and diatom evolution. That record was used to examine the patterns and drivers of morphological evolution of an endemic species complex of diatoms in the lake, the Cyclostephanos andinus complex. In an attempt to delineate species within the complex based on morphology, no discernible evidence was found for species separation based on an ordination analysis of multiple characters, but multiple populations were detected based on the distribution of valve size in individual samples. Likelihood modeling of phyletic evolution showed that size evolved through punctuated change. Correlation of size trends with environmental variables indicates that C. andinus size responded to regional environmental change driven by global processes that influenced Lake Titicaca by affecting lake level and thermal stratification. © 2018 The Paleontological Society. All rights reserved. Article 2018 10.1017/pab.2017.27 Paleobiology 44 89 – 100 1 Altiplano; Bolivia; Lake Titicaca; Peru; Bacillariophyta; Cyclostephanos andinus; biodiversity; diatom; endemic species; endemism; environmental change; fossil record; lake level; morphology; paleoenvironment; species complex https://www.scopus.com/inward/record.uri?eid=2-s2.0-85047106447&doi=10.1017%2fpab.2017.27&partnerID=40&md5=fedc9622d4e3f0593f63ebb194d8f3b8 Cited by: 10 Trisha L. Spanbauer Sherilyn C. Fritz Paul A. Baker article Lacey2018109 We investigate the modern hydrology of Lake Ohrid (Macedonia/Albania) using a combined hydrological and isotope-based modelling approach and present a new evaluation of contemporary water balance and palaeoclimate estimates. The combined model is able to estimate hydrological components that cannot be directly measured, and indicates that sublacustrine spring inflow is in the order of 50% higher than previous estimates and groundwater outflow comprises approximately a third of overall water outflow. In combination with sediment core oxygen isotope data, we used the combined model to quantitatively reconstruct past climate, in particular precipitation, during the early Holocene and last glacial period. Calculated precipitation in the early Holocene was higher than the value for present day and was approximately 44% lower than present during the last glacial, assuming the majority of precipitation fell as snow. The estimated amount of precipitation in the last glacial would have been high enough to provide refugial conditions at Lake Ohrid and to support the continuous existence of arboreal vegetation in the catchment. The improved understanding of the modern isotope hydrology of Lake Ohrid is fundamental for explaining the systematics of past isotope variation and providing context for extended sediment records from the lake, which will provide longer-term palaeoclimate reconstructions covering multiple glacial-interglacial cycles. © 2018 Elsevier Ltd 2018 English 02773791 10.1016/j.quascirev.2018.09.007 Quaternary Science Reviews 202 Elsevier Ltd 109-121 NERC Isotope Geosciences Facilities, British Geological Survey, Keyworth, Nottingham, United Kingdom; School of Geography, University of Nottingham, Nottingham, United Kingdom Catchments; Glacial geology; Groundwater; Isotopes; Lakes; Models; Precipitation (chemical); Salinity measurement, Balkan peninsulas; Glacial-interglacial cycles; Isotope variation; Lake Ohrid; Last glacial period; Palaeoclimate reconstruction; Stable isotopes; Water balance, Climate models, chemical mass balance; glacial-interglacial cycle; Holocene; hydrological modeling; hydrology; inflow; isotopic analysis; Last Glacial; outflow; oxygen isotope; paleoclimate; precipitation (climatology); quantitative analysis; reconstruction; sediment core; stable isotope; water budget, Albania; Balkans; Lake Ohrid; Macedonia [Southern Europe] https://www.scopus.com/inward/record.uri?eid=2-s2.0-85053726791&doi=10.1016%2fj.quascirev.2018.09.007&partnerID=40&md5=f87f1e23ac257dd01c9738094e3fff90 cited By 10 J.H. Lacey M.D. Jones article Lowery2018288 The Cretaceous/Palaeogene mass extinction eradicated 76% of species on Earth 1,2. It was caused by the impact of an asteroid 3,4 on the Yucatán carbonate platform in the southern Gulf of Mexico 66 million years ago 5, forming the Chicxulub impact crater 6,7. After the mass extinction, the recovery of the global marine ecosystem - measured as primary productivity - was geographically heterogeneous 8 ; export production in the Gulf of Mexico and North Atlantic-western Tethys was slower than in most other regions 8-11, taking 300 thousand years (kyr) to return to levels similar to those of the Late Cretaceous period. Delayed recovery of marine productivity closer to the crater implies an impact-related environmental control, such as toxic metal poisoning 12, on recovery times. If no such geographic pattern exists, the best explanation for the observed heterogeneity is a combination of ecological factors - trophic interactions 13, species incumbency and competitive exclusion by opportunists 14 - and 'chance' 8,15,16. The question of whether the post-impact recovery of marine productivity was delayed closer to the crater has a bearing on the predictability of future patterns of recovery in anthropogenically perturbed ecosystems. If there is a relationship between the distance from the impact and the recovery of marine productivity, we would expect recovery rates to be slowest in the crater itself. Here we present a record of foraminifera, calcareous nannoplankton, trace fossils and elemental abundance data from within the Chicxulub crater, dated to approximately the first 200 kyr of the Palaeocene. We show that life reappeared in the basin just years after the impact and a high-productivity ecosystem was established within 30 kyr, which indicates that proximity to the impact did not delay recovery and that there was therefore no impact-related environmental control on recovery. Ecological processes probably controlled the recovery of productivity after the Cretaceous/Palaeogene mass extinction and are therefore likely to be important for the response of the ocean ecosystem to other rapid extinction events. © 2018 Macmillan Publishers Ltd., part of Springer Nature. 2018 10.1038/s41586-018-0163-6 Nature 558 288-291 Institute for Geophysics, Jackson School of Geosciences, University of Texas at Austin, Austin, TX, United States; Department of Geosciences, Pennsylvania State University, University Park, PA, United States; Department of Earth, Ocean and Atmospheric Science, National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL, United States; Departamento de Estratigrafía y Paleontología, Universidad de Granada, Granada, Spain; Faculty of Earth and Life Sciences (FALW), Vrije Universiteit Amsterdam, Amsterdam, Netherlands; Department of Geosciences, University of Alaska Fairbanks, Fairbanks, AK, United States; Analytical, Environmental and Geo-Chemistry, Vrije Universiteit Brussel, Brussels, Belgium; Division of Geological and Planetary Sciences, California Institute of Technology, MS 170-25, Pasadena, CA, United States; Department of Earth Science and Engineering, Imperial College London, London, United Kingdom; British Geological Survey, Edinburgh, United Kingdom; Biogéosciences Laboratory, Université de Bourgogne-Franche Comté, Dijon, France; UK Centre for Astrobiology, School of Physics and Astronomy, University of Edinburgh, Edinburgh, United Kingdom; School of Earth and Planetary Sciences, WA-Organic and Isotope Geochemistry Centre (WA-OIGC), Curtin University, Bentley, WA, Australia; Natural History Museum, Vienna, Austria; Alfred Wegener Institute, Helmholtz Centre of Polar and Marine Research, Bremerhaven, Germany; International Research Institute of Disaster Science, Tohoku University, Sendai, Japan; Lunar and Planetary Institute, Houston, TX, United States; Géosciences Montpellier, CNRS, Université de Montpellier, Montpellier, France; Groupe de Physico-Chimie de ĹAtmosphère, Institut de Chimie et Procédés pour l'Énergie, l'Environnement et la Sante, Université de Strasbourg, Strasbourg, France; Instituto de Geofísica, Universidad Nacional Autónoma De México, Mexico City, Mexico; School of Geographical and Earth Sciences, University of Glasgow, Glasgow, United Kingdom; Argon Isotope Facility, Scottish Universities Environmental Research Centre (SUERC), East Kilbride, United Kingdom; Department of Geology, University of Freiburg, Frieburg, Germany; Cancun, Mexico; Institut für Geologie, Universität Hamburg, Hamburg, Germany; Ocean Resources Research Center for Next Generation, Chiba Institute of Technology, Chiba, Japan; Earth and Planetary Sciences, Rutgers University, New Brunswick, NJ, United States; Kochi Institute for Core Sample Research, Japan Agency for Marine-Earth Science and Technology, Kochi, Japan; LeRoy Eyring Center for Solid State Science, Physical Sciences, Arizona State University, Tempe, AZ, United States; Planetary Science Institute, School of Earth Sciences, China University of Geosciences, Wuhan, China; Department of Chemistry, Toho University, Chiba, Japan; NASA, Astrobiology Institute, Mountain View, CA, United States; CNRS, Institut pour la Recherche et le Développement, Aix Marseille University, Marseille, France 7709 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85048588275&doi=10.1038%2fs41586-018-0163-6&partnerID=40&md5=6e85bc0855bc8e749ce2dc49f7f91dc0 cited By 86 C.M. Lowery T.J. Bralower J.D. Owens F.J. Rodríguez-Tovar H. Jones J. Smit M.T. Whalen P. Claeys K. Farley S.P.S. Gulick J.V. Morgan S. Green E. Chenot G.L. Christeson C.S. Cockell M.J.L. Coolen L. Ferrière C. Gebhardt K. Goto D.A. Kring J. Lofi R. Ocampo-Torres L. Pérez-Cruz A.E. Pickersgill M.H. Poelchau A.S.P. Rae C. Rasmussen M. Rebolledo-Vieyra U. Riller H. Sato S.M. Tikoo N. Tomioka J. Urrutia-Fucugauchi J. Vellekoop A. Wittmann L. Xiao K.E. Yamaguchi W. Zylberman article Nuppunen-Puputti2018 The deep biosphere contains a large portion of the total microbial communities on Earth, but little is known about the carbon sources that support deep life. In this study, we used Stable Isotope Probing (SIP) and high throughput amplicon sequencing to identify the acetate assimilating microbial communities at 2260 m depth in the bedrock of Outokumpu, Finland. The long-term and short-term effects of acetate on the microbial communities were assessed by DNA-targeted SIP and RNA targeted cell activation. The microbial communities reacted within hours to the amended acetate. Archaeal taxa representing the rare biosphere at 2260 m depth were identified and linked to the cycling of acetate, and were shown to have an impact on the functions and activity of the microbial communities in general through small key carbon compounds. The major archaeal lineages identified to assimilate acetate and metabolites derived from the labelled acetate were Methanosarcina spp., Methanococcus spp., Methanolobus spp., and unclassified Methanosarcinaceae. These archaea have previously been detected in the Outokumpu deep subsurface as minor groups. Nevertheless, their involvement in the assimilation of acetate and secretion of metabolites derived from acetate indicated an important role in the supporting of the whole community in the deep subsurface, where carbon sources are limited. © 2018 by the authors. Licensee MDPI, Basel, Switzerland. Article 2018 English 20763263 10.3390/geosciences8110418 Geosciences (Switzerland) 8 MDPI AG 11 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85056812256&doi=10.3390%2fgeosciences8110418&partnerID=40&md5=a1d5c3c27e99504453497dc73653bc3c Cited by: 11; All Open Access, Gold Open Access, Green Open Access Maija Nuppunen-Puputti Lotta Purkamo Riikka Kietäväinen Mari Nyyssönen Merja Itävaara Lasse Ahonen Ilmo Kukkonen Malin Bomberg article song2018morphology 2018 Diqiu Kexue 43 Gai Kan Bianjibu 1997-2006 6 Y Song Z Qian J Zhang S Andrei article Schmincke2018 The Incekaya hyaloclastite cone (eastern Anatolia, Turkey), the focal point along a major eruptive fissure, was the main source of an unusually large explosive basaltic eruption. The ca. 80 ka-old eruption began onshore with scoria cones from a 5 km N-S fracture propagating toward Lake Van (surface area of 3755 km2). At the intersection with the fault-bounded lake basin, a ca. 400-m-high subaerial hyaloclastite edifice formed, which can be crudely subdivided into a main lower massive bulk of hydrothermally altered lithic-rich hyaloclastites (CL) topped unconformably by a &gt; 30-m-thick, well-bedded fallout tephra (CU). The CU tephras are correlated with (1) widespread onshore hyaloclastite fallout deposits mostly west-southwest of the cone and (2) a ca. 2-m-thick, ca 80-ka-old bedded hyaloclastite (V-60), part of a 220 m ICDP (International Continental Scientific Drilling Program) core, drilled in Lake Van, 27 km N of Incekaya. The hyaloclastite unit was seismically identified as being the most widespread and well-defined reflector throughout much of western Lake Van. A minimum volume of &gt; 9 km3 fallout hyaloclastite tephra is estimated when the area of the seismic reflector is extrapolated to the coast and 2 km inland. Seismic reflectors also suggest at least two (hyaloclastite?) intralake cones rising up to 388 m above the lake sediment surface 1.5 km NW off Incekaya cone and were possibly erupted along the same fracture. The total volume of hyaloclastites includes (a) subaerial Incekaya cone, (b) the inferred subaqueous continuation of the cone(s), (c) the bedded intralake and onshore deposits, and, tentatively, (d) a widespread (seismically defined) mass flow deposits directly beneath Incekaya reflector of roughly 20 km3 and may represent the deposits of explosively erupted basaltic magma. Sideromelane shards, the main clast type, are dominantly angular, and most show ≪ 50 vol.% vesicles. Less common tachylite clasts are poorly vesicular (&lt; 50 vol.%). Structural transitions and interlayering between tachylite and sideromelane are ubiquitous. Fluidal and pumiceous lapilli are present in the basal massive facies. Bulk rock and glass compositions indicate constant composition of the slightly evolved Al-rich basalt magma. Olivine (Fo78–82) and plagioclase (An70–80) microphenocrysts, many skeletal with growth features, and microlites make up &lt; 1 vol.% and suggest rapid magma ascent. The high explosive energy of the eruption is interpreted to be due to (1) high magma discharge rates and shearing in the eruptive jet and (2) magma-water interaction conditions. Approximate temporal coincidences with the Incekaya eruption include the following: (a) an abrupt cessation in the supply of evolved tephra from the adjacent Süphan Volcano to the lake sediments, which ended abruptly for ca. 60 ky, (b) an extreme fall in lake level by ca. 150 m, and (c) a drastic increase in pore water salinity (Na+ and Cl− (g/L)) and pH. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature. 2018 English 02588900 10.1007/s00445-018-1257-6 Bulletin of Volcanology 80 Springer Verlag GEOMAR Helmholtz Centre for Ocean Research Kiel, Wischhofstr. 1-3, Kiel, 24148, Germany; Korea Institute of Geoscience and Mineral Resources (KIGAM), 124 Gwahak-ro, Yuseong-gu, Daejeon 34132, South Korea 12 fissure; hyaloclastite; phreatomagmatism; plinian eruption; pyroclastic deposit; volcanic eruption; volcanism, Lake Van; Turkey https://www.scopus.com/inward/record.uri?eid=2-s2.0-85056118270&doi=10.1007%2fs00445-018-1257-6&partnerID=40&md5=cafc8c93f618a9f921538beb98955f6d cited By 0 H.-U. Schmincke M. Sumita D. Cukur article Bräuer2018131 We report new data of the regional distribution pattern of total gas compositions as well as He and CO2 isotopic compositions from 25 gas exhalations in the western Eger Rift and its surroundings. Additionally, the first time-series data from gas exhalations in a clay pit within the Cheb Basin (CB) are given. At 21 degassing locations, the first data were obtained >20 years ago. From 7 locations within the degassing center CB and from 3 degassing sites belonging to the Mariánské Lázně (ML) degassing center, neon and argon isotope compositions were determined also. CO2 is the major component at all degassing sites. The δ13C values display a small range (−1.7 to −5.1‰) and the 3He/4He ratios vary from 1.9 to 5.9 Ra. The highest 3He/4He ratios are found at locations along the Počatky-Plesná Fault Zone, followed by the degassing site in the clay pit on the Nová Ves Fault and the locations on the ML fault at the edge of the CB. Although gas flow and CO2 concentrations in all degassing centers are very high, the fractions of mantle-derived helium are different, with presently up to 94% (in relation to the SCLM 3He/4He of 6.32 Ra) in the CB, up to 73% in the ML and up to 35% in the Karlovy Vary degassing center. At the locations in the eastern part of the CB a clear, progressive increase of the 3He/4He ratio has been observed since the first sampling campaigns there in 1993 and 1994, whereas at the other degassing sites the helium isotope ratio remained essentially the same. The progressive increase of the 3He/4He ratio in the eastern part of the CB, together with further short-time increases up to 6.3 Ra at one location (Bublák) before both the 2000 and 2008 earthquake swarms, indicate an ongoing magmatic process beneath this area, which seems to be associated with the occurrence of seismicity. The CB is located close to the Nový Kostel focal zone where since the beginning of our investigations four strong periods of seismicity (with magnitudes >3) occurred. The latest gas data confirm our earlier findings: time-series studies showed that in relation with seismic events, decreased 3He/4He ratios were repeatedly observed due to admixed seismically released crustal helium. Presently, the eastern part of the CB is the most active non-volcanic region in the European Cenozoic Rift System, with gas signatures similar to those found in free mantle-derived gases from the East African Rift system. © 2018 Elsevier B.V. Article 2018 English 00092541 10.1016/j.chemgeo.2018.02.017 Chemical Geology 482 Elsevier B.V. 131 – 145 Cheb Basin; Czech Republic; Karlovarsky; Carbon; Carbon dioxide; Degassing; Flow of gases; Gases; Helium; Inert gases; Isotopes; Location; Seismology; Time series; Earthquake swarms; Eger Rift; Isotopic composition; Magmatic CO2; Regional distribution; Sampling campaigns; SCLM; ^3He/^4He ratios; carbon dioxide; carbon isotope; helium isotope; isotopic composition; isotopic ratio; magmatism; monitoring; noble gas; rift zone; seismicity; Earthquakes https://www.scopus.com/inward/record.uri?eid=2-s2.0-85042048926&doi=10.1016%2fj.chemgeo.2018.02.017&partnerID=40&md5=c66091ee56dcfaabe987f88772ace1a3 Cited by: 19 Karin Bräuer Horst Kämpf Samuel Niedermann Gerhard Strauch article Schuck2018172 The Alpine Fault is capable of generating large (MW &gt; 8) earthquakes and is the main geohazard on South Island, NZ, and late in its 250–291-year seismic cycle. To minimize its hazard potential, it is indispensable to identify and understand the processes influencing the geomechanical behavior and strength-evolution of the fault. High-resolution microstructural, mineralogical and geochemical analyses of the Alpine Fault's core demonstrate wall rock fragmentation, assisted by mineral dissolution, and cementation resulting in the formation of a fine-grained principal slip zone (PSZ). A complex network of anastomosing and mutually cross-cutting calcite veins implies that faulting occurred during episodes of dilation, slip and sealing. Fluid-assisted dilatancy leads to a significant volume increase accommodated by vein formation in the fault core. Undeformed euhedral chlorite crystals and calcite veins that have cut footwall gravels demonstrate that these processes occurred very close to the Earth's surface. Microstructural evidence indicates that cataclastic processes dominate the deformation and we suggest that powder lubrication and grain rolling, particularly influenced by abundant nanoparticles, play a key role in the fault core's velocity-weakening behavior rather than frictional sliding. This is further supported by the absence of smectite, which is reasonable given recently measured geothermal gradients of more than 120 °C km−1 and the impermeable nature of the PSZ, which both limit the growth of this phase and restrict its stability to shallow depths. Our observations demonstrate that high-temperature fluids can influence authigenic mineral formation and thus control the fault's geomechanical behavior and the cyclic evolution of its strength. © 2018 Elsevier Ltd 2018 English 01918141 10.1016/j.jsg.2018.03.001 Journal of Structural Geology 110 Elsevier Ltd 172-186 Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences, Section 4.2: Geomechanics and Rheology, Telegrafenberg, Potsdam, 14473, Germany; Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences, Section 3.1: Inorganic and Isotope Geochemistry, Telegrafenberg, Potsdam, 14473, Germany; Department of Geology, University of Otago, P.O. Box 56, Dunedin, 9045, New Zealand; University of Potsdam, Institute of Earth and Environmental Sciences, Potsdam, Germany Analytical geochemistry; Calcite; Complex networks; Deformation; Earthquakes; Faulting; Geomechanics; Hazards; Microstructure; Rock bursts; Structural geology, Alpine Faults; Authigenic minerals; Brittle deformation; Fault rock; Fluid-rock interaction, Minerals, authigenic mineral; brittle deformation; fault; fluid-structure interaction; microstructure; nanoparticle; rock mechanics, New Zealand; South Island https://www.scopus.com/inward/record.uri?eid=2-s2.0-85043468569&doi=10.1016%2fj.jsg.2018.03.001&partnerID=40&md5=753d052854ccf2297c7561aebe22f87b cited By 6 B. Schuck C. Janssen A.M. Schleicher V.G. Toy G. Dresen article Malin2018 Article 2018 10.1038/s41598-018-34563-9 Scientific Reports 8 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85055907317&doi=10.1038%2fs41598-018-34563-9&partnerID=40&md5=d7ee2cf1f3e5b2e42d8b1e7f252bf193 Cited by: 21; All Open Access, Gold Open Access, Green Open Access Peter E. Malin Marco Bohnhoff Felix Blümle Georg Dresen Patricia Martínez-Garzón Murat Nurlu Ulubey Ceken Filiz Tuba Kadirioglu Recai Feyiz Kartal Tuğbay Kiliç Kenan Yanik article Vuillemin2018 Article 2018 10.1093/femsec/fiy029 FEMS Microbiology Ecology 94 4 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85043793404&doi=10.1093%2ffemsec%2ffiy029&partnerID=40&md5=41e2c4bc2c8f0b3be87c29a25bf1a707 Cited by: 45; All Open Access, Green Open Access, Hybrid Gold Open Access Aurèle Vuillemin Daniel Ariztegui Fabian Horn Jens Kallmeyer William Orsi Flavio Anselmetti Hugo Corbella Pierre Francus Andreas Lücke Nora I. Maidana Christian Ohlendorf Bernd Zolitschka Frank Schäbitz Stefan Wastegård article Zhu2018187 Songke Well No.2, one of the main part of the scientific drilling project in Songliao Basin, which was drilled 7018 m and acquired the part of cores continuously from the Low Cretaceous to the Carboniferous and the Permian from the 2843 m deep, can be considered as the deepest continental drilling project in Asia. Aiming at the features of longer well sections, larger diameters and multiple spud-ins for coring of Songke Well No.2, this project broke through the “coring in small diameter and reaming in large diameter” spud-in drilling-completion procedures which are always used in large-diameter-well coring for continental scientific drilling projects in domestic and overseas and the drilling method of short-single-cylinder roundtrip footage. At the same time, “coring in the same diameter and completing drilling at one single diameter” was achieved at all φ311 mm and φ216 mm coring sections of more than one thousand meters long, high-efficient operation with “drilling long footage with drill tools combined in multi-cylinders” was achieved at deep coring section. Four world drilling records were created which include more than a thousand meters continuous coring at φ311 mm, and the footage per roundtrip footage at φ311 mm, φ216 mm and φ152 mm is all more than 30 m, all of these breakthroughs reduced at least 300 days for this project; moreover, considering the characteristics of formations that the geothermal gradient is high in the drilled sections and the inside-well temperature is over 240°C after drilling completion, a formate-polymer water-based mud system was developed by compounding attapulgite and sodium bentonite and by adding independently developed high-temperature stabilizer, which can provide critical technical support for successful well completion at 7018 m in the super-high-temperature environment It is the first time that the water-based mud is operated at the working temperature higher than 240°C in China; Besides, considering the high-quality requirement on cores imposed by the project, the method “mechanical cored is charge” to discharge core nondestructively on the ground was worked out, and more than 4000 m scatheless cores were discharged out of the drill pipes while maintaining original stratum structures. © 2019 Elsevier B.V. 2018 English 20965192 10.31035/cg2018031 China Geology 1 KeAi Communications Co. 187-201 Institute of Exploration Techniques, China Geological Survey, Langfang, 065000, China; China University of Geosciences (Wuhan), Wuhan, 430074, China 2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85059667717&doi=10.31035%2fcg2018031&partnerID=40&md5=0ab07e870be4e7d8b73fad0d651a26f7 cited By 10 Y.-Y. Zhu W.-S. Wang X.-M. Wu H.-C. Zhang J. Xu J. Yan L.-L. Cao H.-Q. Ran J.-C. Zhang article Xu2018594 The Lower Jurassic Toarcian Stage (c. 183–174 Ma) is marked by one of the largest global exogenic carbon-cycle perturbations of the Phanerozoic, which is associated with the early Toarcian Oceanic Anoxic Event (T-OAE; c. 183 Ma). Climatic and environmental change at the T-OAE is reasonably well constrained in the marine realm, with marine anoxic or euxinic conditions developing locally across both hemispheres, at the same time as the T-OAE negative carbon-isotope excursion. However, high-resolution stratigraphic comparison between different palaeo-ocean basins and with the continental realm can be complicated. Palaeomagnetic reversals can provide a precise and accurate stratigraphic correlation tool between marine and continental sedimentary archives, and even between sedimentary and igneous successions. Here, we present a high-resolution magnetostratigraphic record for the Toarcian Stage in the biostratigraphically complete and expanded Llanbedr (Mochras Farm) Borehole, Cardigan Bay Basin, Wales. This study provides the first geomagnetic polarity reversal scale that is integrated with high-resolution biostratigraphy and carbon-isotope stratigraphy for the entire Toarcian Stage. This stratigraphic framework also provides a new, precise correlation with the basalt lava sequence of the Karoo–Ferrar Large Igneous Province, linking the Pliensbachian– Toarcian boundary and T-OAE climatic and environmental perturbations directly to this episode of major volcanic activity. © 2018 The Author(s). Article 2018 English 00167649 10.1144/jgs2017-120 Journal of the Geological Society 175 Geological Society of London 594 – 604 4 United Kingdom; Wales; Carbon; Geomagnetism; Isotopes; Sedimentology; Volcanoes; Carbon isotope stratigraphy; Environmental perturbations; Geomagnetic polarity reversal; Large igneous provinces; Negative carbon isotope excursions; Precise correlations; Stratigraphic correlation; Stratigraphic framework; carbon cycle; climate variation; environmental change; magnetostratigraphy; paleoclimate; paleoenvironment; paleomagnetism; Toarcian; Stratigraphy https://www.scopus.com/inward/record.uri?eid=2-s2.0-85049010557&doi=10.1144%2fjgs2017-120&partnerID=40&md5=48d50481f1d61f4699de65226792a716 Cited by: 29; All Open Access, Green Open Access, Hybrid Gold Open Access Weimu Xu Conall Mac Niocaill Micha Ruhl Hugh C. Jenkyns James B. Riding Stephen P. Hesselbo article Yang2018138 In contrast to glacio-eustasy, which is mainly controlled by the waxing and waning of continental ice sheets during icehouse climate stages, the concept of aquifer or limno-eustasy suggests that the effects of groundwater storage and release may have been the main driver of short-term (10s kyr to a few Myr) sea-level changes in the Cretaceous ice-free world. Presumably climate-controlled hydrological cycling could change the water volumes of continental reservoirs and oceans by transporting water between continents and oceans, resulting in out-of-phase relation between lake and sea levels. In the present study, we present lake-level fluctuations in Members 1 and 2 of the Nenjiang Formation (late Santonian-early Campanian) in the Songliao Basin that are indicated by basin-scale correlations of Fischer Plots based on natural gamma-ray logging data. Meanwhile, the Al/K ratios of the SK1 core indicate that changes in precipitation forced lake-level fluctuations in the basin. Compared to global sea-level changes, lake-level fluctuations show an out-of-phase relation with sea-level variations in the lacustrine phase of the basin, suggesting that climate-driven water transport between continents and oceans controlled short-term sea-level changes in the late Santonian-early Campanian. During the phase of marine-lake connectivity (basal Nenjiang Member 1), although the marine regression-driven decrease in lake-level corresponds to salinity stratification and strongly reducing water conditions, increasing precipitation in the basin implies that the hydrological cycle transported more water from the oceans toward continents. Based on the results we suggest that limno-eustasy controlled water levels in the Songliao basin in the late Santonian-early Campanian. © 2018 Elsevier Ltd 2018 English 01956671 10.1016/j.cretres.2018.07.008 Cretaceous Research 92 Academic Press 138-149 State Key Laboratory of Biogeology and Environmental Geology, China University of GeosciencesBeijing 100083, China; School of the Earth Sciences and Resources, China University of GeosciencesBeijing 100083, China; School of Geophysics and Information Technology, China University of GeosciencesBeijing 100083, China; Exploration and Development Research Institute of Daqing Oil Field Corporation, Daqing, Heilongjiang 163712, China Campanian; eustacy; hydrological cycle; lake level; limnology; Santonian, China; Songliao Basin https://www.scopus.com/inward/record.uri?eid=2-s2.0-85051949962&doi=10.1016%2fj.cretres.2018.07.008&partnerID=40&md5=3063ac1ed7234ff8966378f15786810d cited By 10 D. Yang Y. Huang Q. Huang Y. Ren C. Wang article Qin2024168 Article 2018 10.3969/j.issn.1672-7428.2018.10.032 Drilling Engineering 45 171-176 10 H. Zhang J. Yan X. Tan Q. Meng W. Wang L. Cao Y. Zhu J. Xu article 2018 Exploration Engineering (Rock &, Soil Drilling and Tunneling) 45 171-176 10 H. Zhang J. Yan X. Tan Q. Meng W. Wang L. Cao Y. Zhu J. Xu conference Eichelberger20182396 The Krafla Magma Testbed (KMT), Krafla Caldera, Iceland, is proposed to be the first magma observatory, an international multi-borehole facility where teams will conduct scientific experiments and engineering tests focused on the magma-hydrothermal interface in a superhot geothermal systems (SHGS). Objectives are to: 1) Core and monitor from the roots of the hydrothermal system to the top of the magma body; 2) Provide ground-truth testing of surface-based techniques for locating magma; 3) Perturb the deep system to understand signals interpreted as volcano “unrest”; 4) Advance drilling and completion technology so that superhot and supercritical fluids can be produced from the magma roof zone; and 5) Advance sensor technology so that magma bodies can be monitored directly, vastly improving the eruption warnings important to 10% of Earth's population. KMT will provide a vanguard view of magma and hydrothermal circulation as the single system that it is. It will integrate the separate communities of practice of geothermal energy, which relies heavily on direct drilling observations; and volcanology, which relies on surface observations and theoretical models. The driving force is that geothermal drilling hit magma in Iceland, Kenya, and Hawaii, revealing how close to the surface magma exists and how closely connected magma is to the hydrothermal system. KMT is a 3 rd path in efforts to expand geothermal use. One path is to go deeper in cooler places, the Enhanced Geothermal System (EGS) concept, relying on advances in drilling and reservoir stimulation for economic viability, e.g. Frontier Observatory for Research in Geothermal Energy (FORGE) of the U.S. Department of Energy. Another, within SHGS, is to drill to conditions where fluids should be supercritical, e.g. IDDP-2 of Iceland Deep Drilling Program (IDDP) at Reykjanes. The 3 rd , also SHGS and pursued by KMT, is to access the vicinity of a magma body. This takes advantage of magma's high energy density due to latent heat of crystallization and delivered by convection to sustain high power output. Not only have SHGS wells proximal to magma at Krafla Caldera, Iceland, exhibited high flow rates equivalent to >100 MWt, but the expected efficiency of conversion to electricity is ~30% vs. ~10% for conventional geothermal. When combined with the new efficiencies of High Voltage Direct Current (HVDC) tranmission, the economic balance could shift from low-grade geothermal sources near the consumer to high-grade sources farther from the consumer. © 2018 International Journal of Caring Sciences. All rights reserved. Conference paper 2018 English 0934412235 01935933 Transactions - Geothermal Resources Council 42 Geothermal Resources Council 2396 – 2405 Effluent treatment; Geothermal fields; Geothermal wells; Heat convection; HVDC power transmission; Infill drilling; Latent heat; Observatories; Power markets; Quenching; Supercritical fluids; Testbeds; Geothermal; High temperature; Hydrothermal; Magma; Volcanology; Drilling fluids https://www.scopus.com/inward/record.uri?eid=2-s2.0-85059892122&partnerID=40&md5=d2d6049a282566c7dbc0d67715621d0e Cited by: 5 John Eichelberger Hjalti Pall Ingolfsson Charles Carrigan Yan Lavallee Jefferson William Tester Sigurdur H. Markusson conference Hólmgeirsson20182422 Preparations are underway for drilling well KMT-1 of the Krafla Magma Testbed at Krafla, Iceland to sample and instrument the margin of a rhyolite magma body. The project is driven by the need to understand magmatic systems, to improve volcano monitoring strategies, and to develop next-generation, high-enthalpy geothermal energy. The planned depth of the well is 2100 m with cemented casings to 2040 m and a 8 ½” open hole section for coring to 2010 m. The geology for KMT-1 is well known and the well will be located close to IDDP-1 where magma was unexpectedly intersected at 2102 m depth in 2009. © 2018 International Journal of Caring Sciences. All rights reserved. Conference paper 2018 English 0934412235 01935933 Transactions - Geothermal Resources Council 42 Geothermal Resources Council 2422 – 2434 Commerce; Drilling; Geothermal energy; Geothermal fields; Power markets; Testbeds; Coring; Engineering challenges; Magma; Magma bodies; Magmatic systems; Open holes; Volcano monitoring; Well design; Infill drilling https://www.scopus.com/inward/record.uri?eid=2-s2.0-85059896182&partnerID=40&md5=79759bce5701edfcd9a183bc118caeae Cited by: 2 Sveinbjörn Hólmgeirsson Hjalti Pall Ingolfsson John Eichelberger Stephen Pye Randy Normann Gunnar Skúlason Kaldal Doug Blankenship Anette Mortensen Sigurður Markússon Sigrun Nanna Karlsdóttir Sunna Ólafsdóttir Wallevik Sigurður Magnús Garðarsson Jefferson Tester Yan Lavallee article Capitani2018 Article 2018 10.1007/s12665-018-7692-z Environmental Earth Sciences 77 13 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85049590889&doi=10.1007%2fs12665-018-7692-z&partnerID=40&md5=b371fafc6fd6ac385d91e187b15ba7a7 Cited by: 6 Giancarlo Capitani Nobuyoshi Miyajima Roberto Sulpizio Maria D’Addabbo Lucia Galimberti Massimo Guidi Giovanni B. Andreozzi article Macario-González201820 A three-step integrative taxonomy approach combining molecular, morphological and ecological methods was successfully used to delimit species boundaries within three freshwater ostracode taxa of the Yucatán Peninsula (Mexico): Darwinulidae, Cypretta and Cypridopsis. These species groups were selected because they are well-suited paleobioindicators for late Pleistocene-early Holocene climatic reconstructions in the region, but their high inter-population morphological variability in recent communities represents a challenge for accurate transfer of information to fossil assemblages. As a first step, we analyzed the congruence of two genes of different inheritance, the mitochondrial COI (cytochrome c-oxidase subunit 1), and the nuclear 18S rDNA (small-subunit rDNA). Second, we tested the lineages discriminated for concordant differentiation in morphology, using morphometry of the carapace and typological analysis of the appendages. The third step assessed the association of occurrences and abundances of lineages to environmental variables. The integration of these methods revealed six hidden species within clades previously considered as a single widely distributed nominal species. Of these, Cypretta elongata sp. nov. and Alicenula yucatanensis sp. nov. are herein formally named and described given their morphological distinctness. Three species of Cypridopsis: Cypridopsis sp. [Ca1 ECO-CH-Z-09396], Cypridopsis sp. [Ca2 ECO-CH-Z-09398], Cypridopsis sp. [Ca3 ECO-CH-Z-09401] and a species that may represent a new genus, Cyprididae sp. [Ca1 ECO-CH-Z-09402], are allocated to a confirmed candidate full species status. Cypretta maya and Cypretta sp., considered a priori as separate species, are recognized as a single species with phenotypic plasticity, attributed to its broad ecological tolerances. For paleoenvironmental reconstructions these results have relevance because the particular carapace morphology of the new species can be correlated with specific ecological traits, thus constituting a potential tool for refining interpretations of fossil assemblages. © 2018 Elsevier GmbH Article 2018 English 00445231 10.1016/j.jcz.2018.04.002 Zoologischer Anzeiger 275 Elsevier GmbH 20 – 36 Yucatan Peninsula; Alicenula; Crustacea; Cypretta; Cyprididae; Cypridopsis; Darwinulidae; Ostracoda; crustacean; DNA; fossil assemblage; gene expression; Neotropical Region; paleoecology; paleoenvironment; reconstruction; taxonomy https://www.scopus.com/inward/record.uri?eid=2-s2.0-85049071632&doi=10.1016%2fj.jcz.2018.04.002&partnerID=40&md5=082d5b431ce8b0f1b66854ac03b72aa4 Cited by: 11 Laura Macario-González Sergio Cohuo Manuel Elías-Gutiérrez Miguel Vences Liseth Pérez Antje Schwalb article Muñoz20181 The West Bohemia/Vogtland region, characterized by the intersection of the Eger (Ohře) Rift and the Mariánské Lázně fault, is a geodynamically active area exhibiting repeated occurrence of earthquake swarms, massive CO2 emanations and mid Pleistocene volcanism. The Eger Rift is the only known intra-continental region in Europe where such deep seated, active lithospheric processes currently take place. We present an image of electrical resistivity obtained from two-dimensional inversion of magnetotelluric (MT) data acquired along a regional profile crossing the Eger Rift. At the near surface, the Cheb basin and the aquifer feeding the mofette fields of Bublák and Hartoušov have been imaged as part of a region of very low resistivity. The most striking resistivity feature, however, is a deep reaching conductive channel which extends from the surface into the lower crust spatially correlated with the hypocentres of the seismic events of the Nový Kostel Focal Zone. This channel has been interpreted as imaging a pathway from a possible mid-crustal fluid reservoir to the surface. The resistivity model reinforces the relation between the fluid circulation along deep-reaching faults and the generation of the earthquakes. Additionally, a further conductive channel has been revealed to the south of the profile. This other feature could be associated to fossil hydrothermal alteration related to Mýtina and/or Neualbenreuth Maar structures or alternatively could be the signature of a structure associated to the suture between the Saxo-Thuringian and Teplá-Barrandian zones, whose surface expression is located only a few kilometres away. © 2018 Elsevier B.V. Article 2018 English 00401951 10.1016/j.tecto.2018.01.012 Tectonophysics 727 Elsevier B.V. 1 – 11 Bohemia; Czech Republic; Germany; Vogtland; Aquifers; Clay alteration; Faulting; Fluids; Magnetotellurics; Conductive channels; Earthquake swarms; Hydrothermal alterations; Lithospheric process; Resistivity modeling; Surface expression; Vogtland; West Bohemia; earthquake swarm; electrical resistivity; fault; hydrothermal alteration; lower crust; magnetotelluric method; Earthquakes https://www.scopus.com/inward/record.uri?eid=2-s2.0-85044308798&doi=10.1016%2fj.tecto.2018.01.012&partnerID=40&md5=bb4963829596b2fa7887c45c697e0477 Cited by: 8 Gerard Muñoz Ute Weckmann Josef Pek Světlana Kováčiková Radek Klanica article Kagan20182806 Article 2018 10.1002/2017JB014117 Journal of Geophysical Research: Solid Earth 123 2806 – 2824 4 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85044845067&doi=10.1002%2f2017JB014117&partnerID=40&md5=e3cee88272af2507b947cd9a201f7fe8 Cited by: 39 Elisa Kagan Mordechai Stein Shmuel Marco article Rohrmüller20181381 After a comprehensive geophysical prospecting the Quaternary Mýtina Maar, located on a line between the two Quaternary scoria cones Komorní hůrka/Kammerbühl and Železná hůrka/Eisenbühl, could be revealed by a scientific drilling at the German–Czech border in 2007. Further geophysical field investigations led to the discovery of another geological structure about 2.5 km ESE of the small town Neualbenreuth (NE-Bavaria, Germany), inferred to be also a maar structure, being the fourth volcanic feature aligned along the NW–SE trending Tachov fault zone. It is only faintly indicated as a partial circular rim in the digital elevation model. Though not expressed by a clear magnetic anomaly, geoelectric and refraction seismic tomography strongly indicates a bowl-shaped depression filled with low-resistivity and low-velocity material, correlating well with the well-defined negative gravity anomaly of − 2.5 mGal. Below ca. 15 m-thick debris layer, successions of mostly laminated sediments were recovered in a 100 m-long sediment core in 2015. Sections of finely laminated layers, likely varves, rich in organic matter and tree pollen, were recognized in the upper (22–30 m) and lower (70–86 m) part of the core, respectively, interpreted as interglacials, whereas mostly minerogenic laminated deposits, poor in organic matter, and (almost) barren of tree pollen are interpreted as clastic glacial deposits. According to a preliminary age model based on magnetostratigraphy, palynology, radiocarbon dating, and cyclostratigraphy, the recovered sediments span the time window from about 85 ka back to about 270 ka, covering marine isotope stages 5–8. Sedimentation rates are in the range of 10 cm ka−1 in interglacials and up to 100 cm ka−1 in glacial phases. The stratigraphic record resembles the one from Mýtina Maar, with its eruption date being derived from a nearby tephra deposit at 288 ± 17 ka, thus supporting the age model of the inferred Neualbenreuth Maar. © 2017, Springer-Verlag GmbH Germany. Article 2018 English 14373254 10.1007/s00531-017-1543-0 International Journal of Earth Sciences 107 Springer Verlag 1381 – 1405 Bayerisches Landesamt für Umwelt/Bavarian Environment Agency, Leopoldstraße 30, Marktredwitz, 95615, Germany; GFZ German Research Centre for Geosciences, Section 3.2, Telegrafenberg, Potsdam, 14473, Germany; Bayerisches Landesamt für Umwelt/Bavarian Environment Agency, Haunstetter Straße 112, Augsburg, 86161, Germany; GFZ German Research Centre for Geosciences, Section 5.2, Telegrafenberg, Potsdam, 14473, Germany; Institute of Earth and Environmental Science, University of Potsdam, Potsdam, Germany; Institute of Geophysics CAS, Bocni II 1401, Praha 4, 141 31, Czech Republic; Senckenberg Research Station of Quaternary Palaeontology Weimar, Weimar, 99423, Germany; Institute of Geography and Geology, University of Greifswald, Greifswald, 17489, Germany 4 Bavaria; Bohemian Massif; Czech Republic; Eger; Germany; Heves; Hungary; digital elevation model; fault zone; geophysical method; maar; magnetostratigraphy; paleoclimate; palynology; Quaternary; radiocarbon dating; tephra; volcanism https://www.scopus.com/inward/record.uri?eid=2-s2.0-85030854959&doi=10.1007%2fs00531-017-1543-0&partnerID=40&md5=786412ed77f31fe322053de74511e21e Cited by: 18 J. Rohrmüller H. Kämpf E. Geiß J. Großmann I. Grun J. Mingram J. Mrlina B. Plessen M. Stebich C. Veress A. Wendt N. Nowaczyk article Sun2018277 A hydraulic top drive is a high-power gyrator used in oil or scientific drilling rigs, whose shaft is connected to drill pipe when it drives drilling tools to excavate well. The output speed of top drive determines the speed of drill bit directly. Load acting on the top drive shaft fluctuates randomly, which will cause top drive output speed hard to be in consistent with the setting value. This paper presents a main transmission system of a hydraulic top drive designed for deep continental scientific drilling, which was built with a multi-stage mechanical structure and a closed circuit hydraulic system with variable displacement pumps and motors. Electro-hydraulic proportional control was applied to vary the speed of the hydraulic top drive. A theoretical model is detailed for the hydraulic top drive main transmission system. Among the new techniques proposed in this paper is a simulation model for studying the performance of hydraulic top drive and capturing speed characteristics under fluctuant load. A drilling experiment of the hydraulic top drive was performed on the CRUST-I drilling rig in CCSD-SK-II well site. This paper concludes by comparing the results of the simulation model with theoretical results and drilling experimental data gathered in the hydraulic top drive possessing the same architecture, components, and control methods used within the simulation model. The drilling experiment and the analysis result showed that the hydraulic top drive could meet the requirements of deep continental scientific drilling and that the speed could be output according to the setting speed with very small oscillation. The simulation model can be used for several applications such as hydraulic top drive design and performance analysis of various drilling conditions. © 2018 Elsevier B.V. 2018 English 09204105 10.1016/j.petrol.2018.04.003 Journal of Petroleum Science and Engineering 167 Elsevier B.V. 277-286 College of Construction Engineering, Jilin University, Changchun, China; Key Laboratory of Drilling and Exploitation Technology in Complex Conditions of Ministry Land Resources, Jilin University, Changchun, China; College of Mechanical Science and Engineering, Jilin University, Changchun, China Digital storage; Drilling rigs; Drills; Electric power transmission; Hydraulic tools; Oil well drilling; Speed, Continental scientific drillings; Electro-hydraulic proportional control; Fluctuating loads; Main transmission systems; Mechanical structures; Speed characteristics; Theoretical modeling; Variable displacement, Transmissions, acceleration; deep drilling; drilling rig; loading; numerical model; performance assessment; velocity https://www.scopus.com/inward/record.uri?eid=2-s2.0-85045577066&doi=10.1016%2fj.petrol.2018.04.003&partnerID=40&md5=64b2cca612b00c00c4306c7288b464db cited By 8 Y. Sun Y. Shi Q. Wang Z. Yao article giuntoli_replacement_2018 The deformation of the middle to lower crust in collisional settings occurs via deformation mechanisms that vary with rock composition, fluid content, pressure, and temperature. These mechanisms are responsible for the accommodation of large tectonic transport distances during nappe stacking and exhumation. Here, we show that fracturing and fluid flow triggered coupled dissolution–precipitation and dissolution–precipitation creep processes, which were responsible for the formation of a mylonitic microstructure in amphibolites. This fabric is developed over a crustal thickness {\textgreater}500 m in the Lower Seve Nappe (Scandinavian Caledonides). Amphibolites display a mylonitic foliation that wraps around albite porphyroclasts appearing dark in panchromatic cathodoluminescence (CL). The albite porphyroclasts were dissected and fragmented by fractures preferentially developed along the (001) cleavage planes and display lobate edges with embayments and peninsular features. Two albite/oligoclase generations, bright in CL, resorbed and overgrew the porphyroclasts, sealing the fractures. Electron backscattered diffraction shows that the two albite/oligoclase generations grew both pseudomorphically and topotaxially at the expense of the albite porphyroclasts and epitaxially around them. These two albite/oligoclase generations also grew as neoblasts elongated parallel to the mylonitic foliation. The amphibole crystals experienced a similar microstructural evolution, as evidenced by corroded ferrohornblende cores surrounded by ferrotschermakite rims that preserve the same crystallographic orientation of the cores. Misorientation maps highlight how misorientations in amphibole are related to displacement along fractures perpendicular to its c-axis. No crystal plasticity is observed in either mineral species. Plagioclase and amphibole display a crystallographic preferred orientation that is the result of topotaxial growth on parental grains and nucleation of new grains with a similar crystallographic orientation. Amphibole and plagioclase thermobarometry constrains the mylonitic foliation development to the epidote amphibolite facies (˜600°C, 0.75–0.97 GPa). Our results demonstrate that at middle to lower crustal levels, the presence of H2O-rich fluid at grain boundaries facilitates replacement reactions by coupled dissolution–precipitation and favours deformation by dissolution–precipitation creep over dislocation creep in plagioclase and amphibole. 2018 en 1525-1314 10.1111/jmg.12445 Journal of Metamorphic Geology 36 1263--1286 9 Caledonides, dissolution–precipitation processes, electron backscatter diffraction, replacement reactions, X-ray mapping https://onlinelibrary.wiley.com/doi/abs/10.1111/jmg.12445 \_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1111/jmg.12445 Francesco Giuntoli Luca Menegon Clare J. Warren article Palchan2018123 The sediments deposited at the depocenter of the Dead Sea comprise high-resolution archive of hydrological changes in the lake's watershed and record the desert dust transport to the region. This paper reconstructs the dust transport to the region during the termination of glacial Marine Isotope Stage 6 (MIS 6; ∼135–129 ka) and the last interglacial peak period (MIS5e, ∼129–116 ka). We use chemical and Nd and Sr isotope compositions of fine detritus material recovered from sediment core drilled at the deepest floor of the Dead Sea. The data is integrated with data achieved from cores drilled at the floor of the Red Sea, thus, forming a Red Sea-Dead Sea transect extending from the desert belt to the Mediterranean climate zone. The Dead Sea accumulated flood sediments derived from three regional surface cover types: settled desert dust, mountain loess-soils and loess-soils filling valleys in the Dead Sea watershed termed here “Valley Loess”. The Valley Loess shows a distinct 87Sr/86Sr ratio of 0.7081 ± 1, inherited from dissolved detrital calcites that originate from dried waterbodies in the Sahara and are transported with the dust to the entire transect. Our hydro-climate and synoptic conditions reconstruction illustrates the following history: During glacial period MIS6, Mediterranean cyclones governed the transport of Saharan dust and rains to the Dead Sea watershed, driving the development of both mountain soils and Valley Loess. Then, at Heinrich event 11, dry western winds blew Saharan dust over the entire Red Sea - Dead Sea transect marking latitudinal expansion of the desert belt. Later, when global sea-level rose, the Dead Sea watershed went through extreme aridity, the lake retreated, depositing salt and accumulating fine detritus of the Valley Loess. During peak interglacial MIS 5e, enhanced flooding activity flushed the mountain soils and fine detritus from all around the Dead Sea and Red Sea, marking a significant “contraction” of the desert belt. At the end of MIS 5e the effect of the regional precipitation diminished and the Dead Sea and Red Sea areas re-entered sever arid conditions with extensive salt deposition at the Dead Sea. © 2017 Elsevier Ltd 2018 English 02773791 10.1016/j.quascirev.2017.09.004 Quaternary Science Reviews 179 Elsevier Ltd 123-136 The Fredy & Nadine Herrmann Institute of Earth Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel; Geological Survey of Israel, Jerusalem, Israel; Lamont-Doherty Earth Observatory and Department of Earth and Environmental Sciences, Columbia University, Palisades, NY, United States Binary alloys; Chloride minerals; Climatology; Dust; Floods; Floors; Glacial geology; Isotopes; Lakes; Landforms; Neodymium; Neodymium alloys; Sea level; Seawater; Soils; Storms; Strontium; Strontium alloys; Watersheds, Dead sea; Dust sources; Late quaternary; Levant; Loess; Nd-Sr isotopes; Paleo-climate; Paleo-synoptic; Red sea, Sediments, depocenter; dust; flood; flooding; Heinrich event; hydrological change; isotopic composition; Last Interglacial; loess; marine isotope stage; Mediterranean environment; paleoclimate; particle size; precipitation (climatology); Quaternary; sea level change; sediment core; strontium; strontium isotope; watershed, Dead Sea; Indian Ocean; Levantine Sea; Mediterranean Sea; Red Sea [Indian Ocean]; Sahara https://www.scopus.com/inward/record.uri?eid=2-s2.0-85034644909&doi=10.1016%2fj.quascirev.2017.09.004&partnerID=40&md5=cfc6b9cadd7793658ae13efdcb11a3f6 cited By 15 D. Palchan M. Stein S.L. Goldstein A. Almogi-Labin O. Tirosh Y. Erel article Ahlborn2018425 Identifying climates favoring extreme weather phenomena is a primary aim of paleoclimate and paleohydrological research. Here, we present a well-dated, late Holocene Dead Sea sediment record of debris flows covering 3.3 to 1.9 cal ka BP. Twenty-three graded layers deposited in shallow waters near the western Dead Sea shore were identified by microfacies analysis. These layers represent distal subaquatic deposits of debris flows triggered by torrential rainstorms over the adjacent western Dead Sea escarpment. Modern debris flows on this escarpment are induced by rare rainstorms with intensities exceeding &gt;30 mm h-1 for at least one hour and originate primarily from the Active Red Sea Trough synoptic pattern. The observed late Holocene clustering of such debris flows during a regional drought indicates an increased influence of Active Red Sea Troughs resulting from a shift in synoptic atmospheric circulation patterns. This shift likely decreased the passages of eastern Mediterranean cyclones, leading to drier conditions, but favored rainstorms triggered by the Active Red Sea Trough. This is in accord with present-day meteorological data showing an increased frequency of torrential rainstorms in regions of drier climate. Hence, this study provides conclusive evidence for a shift in synoptic atmospheric circulation patterns during a late Holocene drought. Copyright © University of Washington. Published by Cambridge University Press, 2018. 2018 English 00335894 10.1017/qua.2018.9 Quaternary Research (United States) 89 Cambridge University Press 425-431 Section 5.2: Climate Dynamics and Landscape Evolution, GFZ German Research Centre for Geosciences, Telegrafenberg, Potsdam, D-14473, Germany; Fredy and Nadine Herrmann Institute of Earth Sciences, Hebrew University of Jerusalem, Edmond J. Safra Campus - Givat Ram, Jerusalem, 9190401, Israel; Department of Earth Sciences, University of Geneva, Rue des Maraîchers 13, Genève, CH-1205, Switzerland; Earth and Environmental Sciences Department, Al-Quds University, Abu-Dis, P.O. Box: 89, Jerusalem, Israel 2 Climatology; Debris; Drought; Floods, Dead sea; Debris flows; Holocenes; Lake sediments; Levant; Paleoclimates; Red sea, Thunderstorms, atmospheric circulation; cyclone; debris flow; drought; facies analysis; flood; geological record; Holocene; lacustrine deposit; microfacies; paleoclimate; paleohydrology; rainstorm; trough, Dead Sea; Indian Ocean; Levant; Mediterranean Region; Red Sea [Indian Ocean] https://www.scopus.com/inward/record.uri?eid=2-s2.0-85045001361&doi=10.1017%2fqua.2018.9&partnerID=40&md5=f11bf3bfa7b6d7cf6a4af32a3bd8e612 cited By 15 M. Ahlborn M. Armon Y. Ben Dor I. Neugebauer M.J. Schwab R. Tjallingii J.H. Shoqeir E. Morin Y. Enzel A. Brauer article jie2018ultra The well Songke-2 is a high temperature deep scientific exploration well deployed in the Songliao Basin, its purpose is to penetrate the Cretaceous formations to obtain the records of basal continental deposit. The bottom hole temperature has been predicted to be over 220 ℃. Measures for preventing borehole wall collapse are especially important in drilling the fourth and fifth intervals since borehole wall collapse has occurred previously in drilling the interbedded mudstone and sandstone in the Shahezi formation, and the broken tuff, mudstone and coal seam in the Huoshiling formation, which were to be penetrated by the fourth and fifth intervals of the well. Continuous coring was to be conducted in the fourth and fifth intervals, and frequent tripping of drill string gave a big challenge to borehole wall stabilization because of long time contact of the open hole with drilling fluid. The adoption of different drilling techniques in turn gave a challenge to drilling fluid. A high temperature polymer drilling fluid has been formulated to deal with these challenges. The composition of the drilling fluid is as follows: 1.0% bentonite + 2% attapulgite +0.2%KOH +(0.5%-1.0%) high MW filter loss reducer +1% moderate MW filter loss reducer + 2.5% filming agent + (2%-4%)SMC +2%FT +3%KCl + 2%NaCOOH +3% white oil. At the beginning of the fourth interval, the mud left over from the third interval was evaluated and converted for re-use in the fourth interval based on large amount of pilot tests. In the fifth interval, the property of the mud was greatly modified because of the needs for dealing with downhole troubles. When the downhole troubles were resolved, the mud property was gradually adjusted to a stable state. In field application the mud property was adjusted at all times in accordance with the requirements of drilling operations. The mud had good rheology at high temperatures and good high temperature stability. High temperature resistance of the mud formulation was 240 ℃ based on laboratory test. The mud property was still satisfactory even after hot rolling for 72 ℃, providing strong technical support for the success of drilling operation. The drilling fluid technology used in drilling the well Songke-2 is of guiding significance in improving job quality of drilling and reducing exploration cost. © 2018, The Editorial Board of Drilling Fluid & Completion Fluid. All right reserved. Article 2018 Chinese 10015620 10.3969/j.issn.1001-5620.2018.02.004 钻井液与完井液 35 钻井液与完井液 29-34 2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85055041483&doi=10.3969%2fj.issn.1001-5620.2018.02.004&partnerID=40&md5=9cc87b1721143da78dabd5d51e18c7e6 Cited by: 8 Xu Jie Wu Xiaoming Wang Wenshi Yan Jia Zhang Hengchun Cao Longlong article Mohr-Westheide20181516 The oldest known large bolide impacts onto Earth are represented by approximately 3.47–3.2 Ga old Archean spherule layers of the Barberton Greenstone Belt (BGB) in South Africa and the Pilbara craton in West Australia. These layers were recognized as impact deposits by their excessively high platinum group element (PGE) contents that are indicative of an extraterrestrial component. This was followed by measurements of extraterrestrial Cr isotopic ratios, in some cases. Recently, the extraterrestrial PGE signature in Archean spherule layers from the BGB was localized and positively associated with the presence of submicrometer PGE alloy micronuggets associated with Ni,Cr-rich spinel. The actual formation of these platinum group mineral (PGM) phases has, however, not yet been resolved. Primary meteoritic particles from the impacting body, the products of impact melting, or condensation from impact vapor plumes have all been proposed as possible genetic process. Resolving this requires detailed microanalytical investigation of the internal microchemical and microstructural compositions, textural characteristics, and crystallographic relationships between the different phases. Here, we report the results of a first transmission electron microscopy (TEM) study of six such PGE microparticles enclosed in Ni-Cr spinel or occurring in groundmass of Barberton spherule layers from the BARB5 ICDP drill core and from the CT3 exploration core. Results include a variety of chemical and structural PGM compositions that are difficult to explain by a single process, leading to the conclusion that several processes may have been involved in the formation of PGMs in Archean spherule layers from the BGB. There is evidence supporting formation of these PGMs by exsolution from the spinel host phase, precipitation from a melt phase, and condensation from a gas phase (of the impact vapor plume). © The Meteoritical Society, 2018. Article 2018 English 10869379 10.1111/maps.13109 Meteoritics and Planetary Science 53 University of Arkansas 1516 – 1536 7 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85046454491&doi=10.1111%2fmaps.13109&partnerID=40&md5=3a8e670b05e87c05230e942d0e4b7853 Cited by: 3; All Open Access, Bronze Open Access T. Mohr-Westheide A. Greshake R. Wirth W.U. Reimold article Foerster2018111 Deciphering paleoclimate from lake sediments is a challenge due to the complex relationship between climate parameters and sediment composition. Here we show the links between potassium (K) concentrations in the sediments of the Chew Bahir basin in the Southern Ethiopian Rift and fluctuations in the catchment precipitation/evaporation balance. Our micro-X-ray fluorescence and X-ray diffraction results suggest that the most likely process linking climate with potassium concentrations is the authigenic illitization of smectites during episodes of higher alkalinity and salinity in the closed-basin lake, due to a drier climate. Whole-rock and clay size fraction analyses suggest that illitization of the Chew Bahir clay minerals with increasing evaporation is enhanced by octahedral Al-to-Mg substitution in the clay minerals, with the resulting layer charge increase facilitating potassium-fixation. Linking mineralogy with geochemistry shows the links between hydroclimatic control, process and formation of the Chew Bahir K patterns, in the context of well-known and widely documented eastern African climate fluctuations over the last 45,000 years. These results indicate characteristic mineral alteration patterns associated with orbitally controlled wet-dry cycles such as the African Humid Period (~15–5 ka) or high-latitude controlled climate events such as the Younger Dryas (~12.8–11.6 ka) chronozone. Determining the impact of authigenic mineral alteration on the Chew Bahir records enables the interpretation of the previously established μXRF-derived aridity proxy K and provides a better paleohydrological understanding of complex climate proxy formation. © 2018 2018 English 00310182 10.1016/j.palaeo.2018.04.009 Palaeogeography, Palaeoclimatology, Palaeoecology 501 Elsevier B.V. 111-123 Institute of Geography Education, University of Cologne, Köln, Germany; Department of Geosciences, Georgia State University, Atlanta, GA 30303, United States; Addis Ababa University, School of Earth Sciences, Addis Ababa, Ethiopia; Institute of Earth and Environmental Science, University of Potsdam, Potsdam, Germany; Senckenberg Center for Human Evolution and Palaeoenvironment (HEP), Department of Geosciences, University of Tübingen, Tübingen, Germany; Potsdam Institute for Climate Impact Research (PIK), Potsdam, Germany; German Research Centre for Geosciences (GFZ), Potsdam, Germany alkalinity; authigenic mineral; catchment; clay mineral; climate variation; concentration (composition); evaporation; illitization; lacustrine deposit; mineral alteration; paleoclimate; potassium; precipitation (climatology); proxy climate record; salinity; wetting-drying cycle; Younger Dryas; zeolite, East African Rift; Ethiopian Rift https://www.scopus.com/inward/record.uri?eid=2-s2.0-85046138136&doi=10.1016%2fj.palaeo.2018.04.009&partnerID=40&md5=e0f496813f6f8a6767e27e93c6897003 cited By 25 V. Foerster D.M. Deocampo A. Asrat C. Günter A. Junginger K.H. Krämer N.A. Stroncik M.H. Trauth article Upton20181 It is notoriously difficult to characterise the strength and stress states of major plate boundaries. By taking advantage of the well-constrained stress contribution of topography adjacent to a segmented section of the Alpine Fault, New Zealand, we have identified a mechanical mix that produces the distinct fault segmentation pattern seen in field observations. Slope-generated shear and normal stresses rotate the principal stresses relative to the regional tectonically derived stress state and under certain strength states influence the displacement pattern. Three-dimensional models show that the scale and form of the near-surface partitioning depend on both topographic relief and local fault strength relative to the bedrock. The models suggest the Alpine Fault is weak to moderately weak relative to the bedrock and is a single structure to within c. 500 m of the surface, above which segmentation occurs. Adjacent to the Alpine Fault, the stress state is highly variable. The intermediate principal stress, σ2, is rotated from tectonically dominated, near-vertical beneath ridges to near-horizontal beneath large valleys. Individual segments along the Alpine Fault dominated by strike-slip faulting, oblique thrusting or thrusting, can be identified by extracting the topographic contribution to the stress state from numerical models. © 2017 The Royal Society of New Zealand. 2018 English 00288306 10.1080/00288306.2017.1397706 New Zealand Journal of Geology and Geophysics 61 Taylor and Francis Asia Pacific 1-8 GNS, Lower Hutt, New Zealand; School of Earth and Climate Sciences, University of Maine, Orono, ME, United States; Climate Change Institute, University of Maine, Orono, ME, United States 1 bedrock; fault; mechanical property; numerical model; plate boundary; strain partitioning; strength; stress field; tectonics; topographic effect, Alpine Fault Zone; New Zealand; South Island; West Coast [South Island]; Whataroa https://www.scopus.com/inward/record.uri?eid=2-s2.0-85034636558&doi=10.1080%2f00288306.2017.1397706&partnerID=40&md5=c21744b18acb16ea5c894bb0ef74406d cited By 10 P. Upton B.R. Song P.O. Koons article Brindle2018230 Three novel species of Bacillariophyta (diatom) are described from the sediments of Paleolake Lorenyang, a large lake that existed in the Turkana Basin, Kenya during the Gelasian age of the Pleistocene Epoch. Sediment cores extracted as part of the Hominin Sites and Paleolakes Drilling Project (HSPDP) were sampled to provide a diatom-based paleoecological record of Paleolake Lorenyang. Preliminary results of the paleoecological analysis unearthed three novel species of diatoms belonging to Surirella and Thalassiosira in the Natoo Member of the Nachukui Formation. Comparisons of Surirella from Paleolake Lorenyang are made to previous reports of Surirella from modern lakes in East Africa and comparisons of Thalassiosira species from the paleolake are made to modern and fossil species reported from East Africa. This is a first report of diatoms in the Natoo Member, which has previously been described as a floodplain deposit, and thus provides evidence of the last occurrence of Paleolake Lorenyang within the Turkana Basin. Herein we describe a new species of Surirella and two Thalassiosira with remarks on morphology and evolution of East African Surirella and Thalassiosira. © 2018 Magnolia Press. Article 2018 English 11793155 10.11646/phytotaxa.371.3.6 Phytotaxa 371 Magnolia Press 230 – 240 3 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85055259850&doi=10.11646%2fphytotaxa.371.3.6&partnerID=40&md5=85176a4dc3ca110855005c4d8b9ddd80 Cited by: 2 Matthew Brindle Joseph Mohan Catherine Beck Jeffery R. Stone article Glikson201861 As distinct from small to medium-size impact events, large asteroid impacts producing explosions more powerful than 107 TNT-equivalent, represented by craters and rebound domes larger than about 100 km in diameter have major consequences including the triggering of major seismic events, tsunami events and extinction episodes. Such events are manifested by the Archaean ~3.25–3.24 Ga impact cluster and associated transformation from greenstone-granite terrains to semi-continental assemblages (Glikson AY, Vickers J, Earth Planet Sci Lett 241:11–20, 2006). These impact events are considered in Chap. 6. The oldest identified mega-impact is the ~3 Ga Maniitsoq structure in southwest Greenland, while younger mega-impact structures &gt;100 km in diameter include the Vredefort and Sudbury structures. Phanerozoic mega-impacts include the Woodleigh impact structure, Warburton twin structures, Chicxulub and Popigai structures. The global tectonic consequences of some of these mega-impacts are yet to be elucidated. © 2018, Springer International Publishing AG. 2018 10.1007/978-3-319-74545-9_3 Modern Approaches in Solid Earth Sciences 14 61-78 Planetary Science Institute, Australian National University, Canberra, ACT, Australia; Centre for Exploration Targeting, The University of Western Australia, Crawley, WA, Australia https://www.scopus.com/inward/record.uri?eid=2-s2.0-85044166424&doi=10.1007%2f978-3-319-74545-9_3&partnerID=40&md5=f19b4ec783e27cadedd0c1d676eaab12 cited By 0 A.Y. Glikson F. Pirajno article Glikson201861 As distinct from small to medium-size impact events, large asteroid impacts producing explosions more powerful than 107 TNT-equivalent, represented by craters and rebound domes larger than about 100 km in diameter have major consequences including the triggering of major seismic events, tsunami events and extinction episodes. Such events are manifested by the Archaean ~3.25–3.24 Ga impact cluster and associated transformation from greenstone-granite terrains to semi-continental assemblages (Glikson AY, Vickers J, Earth Planet Sci Lett 241:11–20, 2006). These impact events are considered in Chap. 6. The oldest identified mega-impact is the ~3 Ga Maniitsoq structure in southwest Greenland, while younger mega-impact structures &gt;100 km in diameter include the Vredefort and Sudbury structures. Phanerozoic mega-impacts include the Woodleigh impact structure, Warburton twin structures, Chicxulub and Popigai structures. The global tectonic consequences of some of these mega-impacts are yet to be elucidated. © 2018, Springer International Publishing AG. 2018 10.1007/978-3-319-74545-9_3 Modern Approaches in Solid Earth Sciences 14 61-78 Planetary Science Institute, Australian National University, Canberra, ACT, Australia; Centre for Exploration Targeting, The University of Western Australia, Crawley, WA, Australia https://www.scopus.com/inward/record.uri?eid=2-s2.0-85044166424&doi=10.1007%2f978-3-319-74545-9_3&partnerID=40&md5=f19b4ec783e27cadedd0c1d676eaab12 cited By 0 A.Y. Glikson F. Pirajno article Sylvestre201871 At present, Lake Chad ( ~13°0 N, ~14° E) is a shallow freshwater lake located in the Sahel/Sahara region of central northern Africa. The lake is primarily fed by the Chari-Logone river system draining a ~600 000 km2 watershed in tropical Africa. Discharge is strongly controlled by the annual passage of the intertropical convergence zone (ITCZ) and monsoon circulation leading to a peak in rainfall during boreal summer. During recent decades, a large number of studies have been carried out in the Lake Chad Basin (LCB). They have mostly focused on a patchwork of exposed lake sediments and outcrops once inhabited by early hominids. A dataset generated from a 673m long geotechnical borehole drilled in 1973, along with outcrop and seismic reflection studies, reveal several hundred metres of Miocene-Pleistocene lacustrine deposits. CHADRILL aims to recover a sedimentary core spanning the Miocene-Pleistocene sediment succession of Lake Chad through deep drilling. This record will provide significant insights into the modulation of orbitally forced changes in northern African hydroclimate under different climate boundary conditions such as high CO2 and absence of Northern Hemisphere ice sheets. These investigations will also help unravel both the age and the origin of the lake and its current desert surrounding. The LCB is very rich in early hominid fossils (Australopithecus bahrelghazali; Sahelanthropus tchadensis) of Late Miocene age. Thus, retrieving a sediment core from this basin will provide the most continuous climatic and environmental record with which to compare hominid migrations across northern Africa and has major implications for understanding human evolution. Furthermore, due to its dramatic and episodically changing water levels and associated depositional modes, Lake Chad's sediments resemble maybe an analogue for lake systems that were once present on Mars. Consequently, the study of the subsurface biosphere contained in these sediments has the potential to shed light on microbial biodiversity present in this type of depositional environment. We propose to drill a total of ~1800m of poorly to semi-consolidated lacustrine, fluvial, and eolian sediments down to bedrock at a single on-shore site close to the shoreline of present-day Lake Chad. We propose to locate our drilling operations on-shore close to the site where the geotechnical Bol borehole (13°280 N, 14°440 E) was drilled in 1973. This is for two main reasons: (1) nowhere else in the Chad Basin do we have such detailed information about the lithologies to be drilled; and (2) the Bol site is close to the depocentre of the Chad Basin and therefore likely to provide the stratigraphically most continuous sequence. © Author(s) 2018. Article 2018 English 18168957 10.5194/sd-24-71-2018 Scientific Drilling 24 Copernicus GmbH 71 – 78 Biodiversity; Boring; Deposition; Infill drilling; Lakes; Sediments; Water levels; Continuous sequences; Depositional environment; Environmental records; Intertropical convergence zone; Microbial biodiversity; Monsoon circulations; Pleistocene sediments; Subsurface biosphere; Climate change https://www.scopus.com/inward/record.uri?eid=2-s2.0-85055480862&doi=10.5194%2fsd-24-71-2018&partnerID=40&md5=fc11976c17b0dce8247881797ce1066a Cited by: 2; All Open Access, Gold Open Access, Green Open Access Florence Sylvestre Mathieu Schuster Moussa Abdheramane Daniel Ariztegui Ulrich Salzmann Nicolas Waldmann Olusegun Adeaga Dave Ahounta Mike Akaegbobi Izuchukwu Likius Andossa Simon Armitage Laurent Augustin Doris Barboni Edouard Bard Melissa Berke Camille Bouchez Didier Bourlès Charles Bristow Eric Brown Christopher Campisano Françoise Chalié Leon Clarke Camille Contoux Martine Couapel Doriane Delanghe Pierre Deschamps Jean-Claude Doumnang Rachel Flecker Uli Harms Jonathan Holmes Reuben Ikhane Phillips Moussa Isseini Guillaume Jouve Juan Larrasoana Anne-Elisabeth Lebatard Suzanne Leroy Youssouf Mahamoud Abdheramane Moussa Dennis Nielson François Nguetsop Reginald C. Njokuocha Anders Noren Naomi Porat Poulin Chloé Lisa Schüler-Goldbach Kazuyo Tachikawa Nicolas Thouveny Benjamin Tutolo Dirk Verschuren Laurence Vidal Finn Viehberg article Weber2018242 Article 2018 10.1016/j.epsl.2018.04.027 Earth and Planetary Science Letters 493 242 – 261 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85046821299&doi=10.1016%2fj.epsl.2018.04.027&partnerID=40&md5=612d72e42ea3e956936df36e2fdbe82d Cited by: 20; All Open Access, Green Open Access Nurit Weber Yoseph Yechieli Mordechai Stein Reika Yokochi Ittai Gavrieli Jake Zappala Peter Mueller Boaz Lazar article Massiot20182492 Ultrasonic image logs acquired in the DFDP-2B borehole yield the first continuous, subsurface description of the transition from schist to mylonite in the hangingwall of the Alpine Fault, New Zealand, to a depth of 818 m below surface. Three feature sets are delineated. One set, comprising foliation and foliation-parallel veins and fractures, has a constant orientation. The average dip direction of 145° is subparallel to the dip direction of the Alpine Fault, and the average dip magnitude of 60° is similar to nearby outcrop observations of foliation in the Alpine mylonites that occur immediately above the Alpine Fault. We suggest that this foliation orientation is similar to the Alpine Fault plane at ∼1 km depth in the Whataroa valley. The other two auxiliary feature sets are interpreted as joints based on their morphology and orientation. Subvertical joints with NW-SE (137°) strike occurring dominantly above ∼500 m are interpreted as being formed during the exhumation and unloading of the Alpine Fault's hangingwall. Gently dipping joints, predominantly observed below ∼500 m, are interpreted as inherited hydrofractures exhumed from their depth of formation. These three fracture sets, combined with subsidiary brecciated fault zones, define the fluid pathways and anisotropic permeability directions. In addition, high topographic relief, which perturbs the stress tensor, likely enhances the slip potential and thus permeability of subvertical fractures below the ridges, and of gently dipping fractures below the valleys. Thus, DFDP-2B borehole observations support the inference of a large zone of enhanced permeability in the hangingwall of the Alpine Fault. ©2018. American Geophysical Union. All Rights Reserved. 2018 English 15252027 10.1029/2017GC007368 Geochemistry, Geophysics, Geosystems 19 Blackwell Publishing Ltd 2492-2515 GNS Science, Avalon, Lower Hutt, New Zealand; SGEES, Victoria University of Wellington, Wellington, New Zealand; Géosciences Montpellier, Université de Montpellier, CNRS, Montpellier, France; Univ. Grenoble Alpes, Univ. Savoie Mont Blanc, CNRS, IRD, IFSTTAR, ISTerre, Grenoble, France; School of Natural Sciences, University of Ireland, Galway, Ireland; Department of Geology, University of Otago, Dunedin, New Zealand; School of Earth and Ocean Sciences, Cardiff University, Cardiff, United Kingdom; Department of Physics, University of Alberta, Edmonton, AB, Canada 8 Anisotropy; Boreholes; Fracture; Stress relief; Ultrasonic imaging; Unloading, Alpine Faults; Anisotropic permeability; Enhanced permeability; Fluid pathways; foliation; Hydrofractures; Slip potential; Stress tensors, Well logging, anisotropy; borehole logging; fault zone; foliation; fracture zone; hanging wall; image analysis; mylonite; outcrop; permeability; structural geology; ultrasonics; well logging, Alpine Fault Zone; New Zealand; South Island https://www.scopus.com/inward/record.uri?eid=2-s2.0-85048900357&doi=10.1029%2f2017GC007368&partnerID=40&md5=aa1b11085031a4f78f860928dddc3ff1 cited By 14 C. Massiot B. Célérier M.-L. Doan T.A. Little J. Townend D.D. McNamara J. Williams D.R. Schmitt V.G. Toy R. Sutherland L. Janku-Capova P. Upton P.A. Pezard article Kirilova2018205 Graphitization in fault zones is associated both with fault weakening and orogenic gold mineralization. We examine processes of graphitic carbon emplacement and deformation in the active Alpine Fault Zone, New Zealand by analysing samples obtained from Deep Fault Drilling Project (DFDP) boreholes. Optical and scanning electron microscopy reveal a microtextural record of graphite mobilization as a function of temperature and ductile then brittle shear strain. Raman spectroscopy allowed interpretation of the degree of graphite crystallinity, which reflects both thermal and mechanical processes. In the amphibolite-facies Alpine Schist, highly crystalline graphite, indicating peak metamorphic temperatures up to 640°C, occurs mainly on grain boundaries within quartzo-feldspathic domains. The subsequent mylonitization process resulted in the reworking of graphite under lower temperature conditions (500-600°C), resulting in clustered (in protomylonites) and foliation-aligned graphite (in mylonites). In cataclasites, derived from the mylonitized schists, graphite is most abundant ( < 50% as opposed to < 10% elsewhere), and has two different habits: inherited mylonitic graphite and less mature patches of potentially hydrothermal graphitic carbon. Tectonic-hydrothermal fluid flow was probably important in graphite deposition throughout the examined rock sequences. The increasing abundance of graphite towards the fault zone core may be a significant source of strain localization, allowing fault weakening. © 2018 The Author(s). 2018 English 03058719 10.1144/SP453.13 Geological Society Special Publication 453 Geological Society of London 205-223 Department of Geology, University of Otago, PO Box 56, Dunedin, 9054, New Zealand; Department of Applied Geology, Western Australian School of Mines, Curtin University of Technology, Bentley, WA 6102, Australia; Microscopy and Microanalysis Facility, John de Laeter Centre, Curtin University, Perth, WA 6854, Australia; Ocean and Earth Science, National Oceanography Centre Southampton, University of Southampton, Southampton, SO14 3ZH, United Kingdom; Institut de Minéralogie de Physique des Matériaux et de Cosmochimie, CNRS-UMP, 4 Place Jussieu, Paris, 75005, France; School of Geography, Environment and Earth Sciences, Victoria University of Wellington, PO Box 600, Wellington, 6140, New Zealand; Department of Earth and Ocean Sciences, University of Liverpool, 4 Brownlow Street, Liverpool, L69 3GP, United Kingdom; School of Geology and Geophysics, University of Oklahoma, Norman, OK 73019, United States; ScopeM - ETH Zürich, HPT D 9, Auguste-Piccard-Hof 1, Zurich, 8093, Switzerland; Faculty of Science, Shinshu University, 3-1-1 Asahi, Matsumoto, Nagano, 390-8621, Japan; Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences, Telegrafenberg, Potsdam, 14473, Germany 1 active fault; carbon; emplacement; fault zone; grain boundary; graphite; mobilization; plate boundary; strain; tectonic setting; texture, Alpine Fault Zone; New Zealand; South Island https://www.scopus.com/inward/record.uri?eid=2-s2.0-85033662326&doi=10.1144%2fSP453.13&partnerID=40&md5=b237b9a4a0fd2dfd26fe949b8a42bb49 cited By 17 M. Kirilova V.G. Toy N. Timms A. Halfpenny C. Menzies D. Craw O. Beyssac R. Sutherland J. Townend C. Boulton B.M. Carpenter A. Cooper J. Grieve T. Little L. Morales C. Morgan H. Mori K.M. Sauer A.M. Schleicher J. Williams L. Craw article Armon20181077 Article 2018 10.1175/JHM-D-18-0013.1 Journal of Hydrometeorology 19 1077 – 1096 6 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85048027669&doi=10.1175%2fJHM-D-18-0013.1&partnerID=40&md5=70a6a7568905b569836c596f387897c2 Cited by: 56 Moshe Armon Elad Dente James A. Smith Yehouda Enzel Efrat Morin article Kirilova2018223 Graphitization, or the progressive maturation of carbonaceous material, is considered an irreversible process. Thus, the degree of graphite crystallinity, or its structural order, has been calibrated as an indicator of the peak metamorphic temperatures experienced by the host rocks. However, discrepancies between temperatures indicated by graphite crystallinity versus other thermometers have been documented in deformed rocks. To examine the possibility of mechanical modifications of graphite structure and the potential impacts on graphite thermometry, we performed laboratory deformation experiments. We sheared highly crystalline graphite powder at normal stresses of 5 and 25 megapascal (MPa) and aseismic velocities of 1, 10 and 100μms1. The degree of structural order both in the starting and resulting materials was analyzed by Raman microspectroscopy. Our results demonstrate structural disorder of graphite, manifested as changes in the Raman spectra. Microstructural observations show that brittle processes caused the documented mechanical modifications of the aggregate graphite crystallinity. We conclude that the calibrated graphite thermometer is ambiguous in active tectonic settings. © Author(s) 2018. This work is distributed under the Creative Commons Attribution 4.0 License. 2018 English 18699510 10.5194/se-9-223-2018 Solid Earth 9 Copernicus GmbH 223-231 Department of Geology, University of Otago, P.O. Box 56, Dunedin, 9054, New Zealand; Department of Chemistry, University of Otago, P.O. Box 56, Dunedin, 9054, New Zealand; Dipartimento di Scienze della Terra, Università degli Studi la Sapienza, Rome, Italy; Faculty of Science, Earth and Planetary Sciences, Hokkaido University, Sapporo, Japan 1 Calibration; Metamorphic rocks; Statistical mechanics; Thermometers, Active tectonic settings; Carbonaceous materials; Crystalline graphite; Degree of structural order; Irreversible process; Micro-structural observations; Raman microspectroscopy; Structural disorders, Graphite, crystal structure; crystallinity; crystallography; experimental mineralogy; graphite; thermometry https://www.scopus.com/inward/record.uri?eid=2-s2.0-85042686131&doi=10.5194%2fse-9-223-2018&partnerID=40&md5=eb9f7539c58a0fd5b8e4e13fd9e768e3 cited By 28 M. Kirilova V. Toy J.S. Rooney C. Giorgetti K.C. Gordon C. Collettini T. Takeshita article Podugu2018120 2018 English 00167622 10.1007/S12594-018-0845-6 Journal of the Geological Society of India 91 Springer 120-124 Borehole Geophysics Research Laboratory (BGRL), Ministry of Earth Sciences,Government of India, India; CSIR-National Geophysical Research Institute, Hyderabad, 500 007, India 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85057112245&doi=10.1007%2fS12594-018-0845-6&partnerID=40&md5=aeb9539fc74a9a728fa77433cd2969f2 cited By 7 N. Podugu A. Yadav K. Mallika D. Goswami M.U. Anuradha article Cvetkoska2018197 The extraordinary diversity in long-lived lakes is largely driven by distinct eco-evolutionary processes. With their unique biota and numerous endemic taxa, these lakes are key settings for fundamental studies related to ecology, diversity, and evolution. Here, we test how the environment shapes diatom diversity and community patterns over space in ancient Lake Ohrid. By applying Bray–Curtis similarity analyses of diatom community data, including widespread and endemic taxa, we identified two major zones: littoral and sublittoral. The latter one is being characterized with higher endemic diversity. The α and β diatom diversity and community distribution in the northern and eastern part of the lake are influenced by the presence of vertical (bathymetrical) and horizontal barriers. The zonation of the diatom communities appears driven by two large-scale factors: (i) water depth, and (ii) water chemistry, primarily, the concentration of total phosphorus, nitrogen ammonia, and conductivity. Both drivers appear to equally influence diatom diversity and community patterns. We present initial data on diatom–environment relations, where the results support earlier ecological studies emphasizing the relevance of ongoing human-induced eutrophication in the northern lake area. This study provides background information on the role of the environment in structuring contemporary diatom diversity. However, future research needs to focus on the biotic component including species competition in order to reveal the mechanisms driving spatial community dynamics in Lake Ohrid. © 2018, The Author(s). Article 2018 English 00188158 10.1007/s10750-018-3637-5 Hydrobiologia 819 Springer International Publishing 197 – 215 1 Bacillariophyta https://www.scopus.com/inward/record.uri?eid=2-s2.0-85048259178&doi=10.1007%2fs10750-018-3637-5&partnerID=40&md5=6b8497418ad874bb072bf9ba2b4e43a2 Cited by: 16; All Open Access, Green Open Access, Hybrid Gold Open Access Aleksandra Cvetkoska Aleksandar Pavlov Elena Jovanovska Slavica Tofilovska Saul Blanco Luc Ector Friederike Wagner-Cremer Zlatko Levkov article Vellekoop2018683 The Chicxulub asteroid impact at the Cretaceous-Paleogene (K-Pg) boundary resulted in one of the most abrupt global warming events in the past 100 m.y., presenting an analogue to current global warming. Here, we present high-resolution geochemical, micropaleontological, and palynological records of the Brazos-1 (Texas, USA), Stevns Klint (Denmark), and Caravaca (Spain) K-Pg boundary sections to assess the rapid environmental changes during the global warming following the brief K-Pg boundary impact winter. Warming during the first millennia after the impact is associated with hypoxic bottom waters at the studied shelf sites, as indicated by molybdenum enrichments, causing major stress for benthic communities. We attribute this decline in dissolved oxygen to a combination of decreased gas solubility and ocean ventilation resulting from the warming of the sea water, and increased oxygen demand in shelf bottom waters due to increased nutrient inputs and associated high productivity. © 2018 Geological Society of America. 2018 10.1130/G45000.1 Geology 46 683-686 Department of Earth and Environmental Sciences, KU Leuven, Heverlee, 3001, Belgium; Analytical, Environmental and Geo-Chemistry (AMGC), Vrije Universiteit Brussel, Brussels, B-1050, Belgium; Department of Earth Sciences, Utrecht University, Utrecht, 3508 TA, Netherlands; Department of Earth, Life and Environmental Sciences, University of Urbino 'Carlo Bo', Urbino, 61029, Italy; Department of Sedimentology and Marine Geology, VU University Amsterdam, Amsterdam, 1018HV, Netherlands 8 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85050501777&doi=10.1130%2fG45000.1&partnerID=40&md5=f8835f60e053533d1a9b1063ecb4b11c cited By 25 J. Vellekoop L. Woelders N.A.G.M. Helmond S. Galeotti J. Smit C.P. Slomp H. Brinkhuis P. Claeys R.P. Speijer article Moore20184515 An exposure of a creeping segment of the Bartlett Springs Fault (BSF), part of the San Andreas Fault system in northern California, is a ~1.5-m-wide zone of serpentinite-bearing fault gouge cutting through Late Pleistocene fluvial deposits. The fault gouge consists of porphyroclasts of antigorite serpentinite, talc, chlorite, and tremolite-actinolite, along with some Franciscan metamorphic rocks, in a matrix of the same materials. The Mg-mineral assemblage is stable at temperatures above 250–300 °C. The BSF gouge is interpreted to have been tectonically incorporated into the fault from depths near the base of the seismogenic zone and to have risen buoyantly to the surface where it is now undergoing right-lateral displacement. The ultramafic-rich composition, frictional properties, and inferred mode of emplacement of the BSF serpentinitic gouge correspond to those of the creeping traces of the San Andreas Fault identified in the SAFOD (San Andreas Fault Observatory at Depth) drill hole. This suggests a common origin for creep at both locations. A tectonic model for the source of the ultramafic-rich materials in the BSF is proposed that potentially could explain the distribution of creep throughout the northernmost San Andreas Fault system. Published 2018. This article is a US Government work and is in the public domain in the USA. 2018 English 02787407 10.1029/2018TC005307 Tectonics 37 Blackwell Publishing Ltd 4515-4534 U. S. Geological Survey, Menlo Park, CA, United States 12 Creep; Kaolinite; Magnesite; Metamorphic rocks; Serpentine; Strike-slip faults, Fault creep; Metasomatic rocks; SAFOD; San Andreas fault; Serpentinite, Structural geology, comparative study; data interpretation; displacement; emplacement; fault gouge; San Andreas Fault; seismic hazard; seismic zone; serpentinite, California; San Andreas; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-85058217106&doi=10.1029%2f2018TC005307&partnerID=40&md5=6527f968b3267ed5fda3ef6063d6afb5 cited By 4 D.E. Moore R.J. McLaughlin J.J. Lienkaemper article Canales-García2018215 Chicxulub Crater, formed ~66Ma ago by an asteroid impact on the southern Gulf of Mexico, is the best preserved of the three large multi-ring basins in the terrestrial record. The crater structure is characterized by a semi-circular concentric ring pattern, marking the crater basin, peak ring, terrace zone and basement uplift. Analysis of a grid of 19 seismic reflection profiles using seismic attributes, marker horizons, contour surfaces and 3-D views is used to investigate the stratigraphy of the central zone. We used interactive software and routine applications to map the impact breccias, breccia-carbonate contact and post-impact carbonates. Four horizons marked by high-amplitude reflectors representing high-impedance contrasts were identified and laterally correlated in the seismic images. Complex trace attribute analysis was applied for petrophysical characterization. Surface contour maps of base and top of stratigraphic packages were constructed, which mapped the impactites and post-and pre-impact carbonate stratigraphy. Basin floor, marked by the contact between the impact breccias and overlying carbonates is shown by laterally discontinuous high-amplitude reflectors. Discontinuous scattered reflectors interpreted as the upper breccias beneath the crater floor, have an average thickness of ~300msm. The Paleogene sedimentary units are characterized by multiple reflectors with lateral continuity, which contrast with the seismic response of underlying breccias. The basal Paleocene sediments follow the basin floor relief. Upwards in the section, the carbonate strata are characterized by horizontal reflectors, which are interrupted by a regional unconformity. Onlap/downlap packages over the unconformity record a period of sea level change. ©I. Canales-García, J. Urrutia-Fucugauchi, E. Aguayo-Camargo, 2018 CC BY-SA. 2018 10.1344/GeologicaActa2018.16.2.6 Geologica Acta 16 215-235 Universidad Nacional Autónoma de México, Ciudad Universitaria, Delegación Coyoacán, México, 04510, Mexico; Instituto de Geofísica, Universidad Nacional Autónoma de México, Departamento de Geomagnetismo y Exploración, Ciudad Universitaria, Delegación Coyoacán, México, 04510, Mexico; Facultad de Ingeniería, Universidad Nacional Autónoma de México, Departamento de Geología, Ciudad Universitaria, Delegación Coyoacán, México, 04510, Mexico 2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85051627567&doi=10.1344%2fGeologicaActa2018.16.2.6&partnerID=40&md5=abb4ebcc5d820b9b65393f9191b1ae52 cited By 4 I. Canales-García J. Urrutia-Fucugauchi E. Aguayo-Camargo article Meyer201892 This study presents the merit of visible-spectrum scanning reflectance spectroscopy (VIS-RS) as a rapid technique for determining the concentration of chlorophyll a (Chl a) and its derivatives in lake sediments. In a 25,000-yr sediment record from Lake Challa, in East Africa, we found that VIS-RS values correlate with Chl a concentrations measured by High Performance/Pressure Liquid Chromatography. Observed variation in sedimentary values of RABD660;670 appears linked to proxies of climatic moisture balance as well as to a seismically-derived lake-level reconstruction over this period, indicating that VIS-RS can be used as a proxy for long-term paleo-hydrological change. Changes in the reflectance of Lake Challa sediments are likely related to differences in the preservation/degradation of algal pigments in response to changes in water-column depth and the stability of stratification. The connecting mechanism may be that during lake lowstands, more frequent injection of oxygen to (near-) bottom waters enhance the breakdown of labile organic compounds before permanent burial. We suggest that fast and inexpensive VIS-RS scanning, although less specific than HPLC in quantifying individual pigments, provides accurate data on down-core variations in the concentration of Chl a and its derivatives in lake sediments, hence allows to reconstruct long-term changes in the hydrology of climate-sensitive lakes. The main prerequisite for its successful application is that temporal variation in lake hydrology over the period of interest has not appreciably affected sedimentation dynamics at the core site, since major changes in sediment texture and organic content are likely to create confounding effects in the VIS-RS signature. © 2017 Association for the Sciences of Limnology and Oceanography 2018 English 15415856 10.1002/lom3.10230 Limnology and Oceanography: Methods 16 Wiley Blackwell 92-105 Renard Centre of Marine Geology (RCMG), Department of Geology, Ghent University, Gent, Belgium; PProGRess/UGCT – Department of Geology, Ghent University, Ghent, Belgium; Protistology and Aquatic Ecology, Department of Biology, Ghent University, Gent, Belgium; Limnology Unit, Department of Biology, Ghent University, Gent, Belgium 2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85042356651&doi=10.1002%2flom3.10230&partnerID=40&md5=0e7ddf519ff2b045ad5d755d3d364965 cited By 9 I. Meyer M. Van Daele G. Fiers E. Verleyen M. De Batist D. Verschuren article Hamdani2018155 Article 2018 10.1016/j.jhydrol.2018.04.057 Journal of Hydrology 562 155 – 167 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85046664238&doi=10.1016%2fj.jhydrol.2018.04.057&partnerID=40&md5=c65d43ca872ff264f3e60c2f0fb1ab92 Cited by: 43 I. Hamdani S. Assouline J. Tanny I.M. Lensky I. Gertman Z. Mor N.G. Lensky article Zou2018679 The Continental Scientific Drilling Project in the Songliao Basin, a major scientific project, was aimed at solving a variety of scientific problems involved in resources on deep strata, paleoclimate and paleoenvironment. As the main borehole of this project, the SK-2 East Borehole was designed to reach a depth of 6 400 m to penetrate the Cretaceous strata until reaching the base of the basin. Geophysical logs played an important role in the subsequent geoscience researches because very few core samples were recovered over the Upper Cretaceous intervals (i.e., Spud 1 and Spud 2). After the borehole was officially drilled, 4 uncased and cased hole logging operations were carried out in the Upper Cretaceous intervals using advanced imaging logging tools. Comprehensive log evaluation was implemented systematically. The preliminary scientific results were summarized as follows: (1) Abundant logs including conventional logs special logs and CBL logs (more than 20 parameters) were obtained in situ, and continuous and standard petrophysical parameters profiles of the Upper Cretaceous interval were established; (2) Stratigraphic division, lithological identification and fine interpretation of sediments and structures were completed; (3) Hydrocarbon reservoirs in the Quantou Formation, source rocks in the Nenjiang and Qingshankou Formation, abnormally high radioactivity interval in the Nenjiang Formation, and potential geothermal development layers over the Upper Cretaceous strata were identified; (4) Favorable geophysical log indexes for paleoclimate analysis in the Qingshankou Formation were studied; (5) The key drilling engineering information including accurate temperature, caliper, borehole trajectory and cementing quality was provided in time. The scientific results are crucial for establishing the scientific scale of geophysical exploration in the Songliao Basin, investigating paleoclimate and paleoenvironment, and implementing drilling engineering, which have established good foundations for achieving the whole scientific goals of this drilling project. © 2018, Science Press. All right reserved. 2018 Chinese 10063021 10.3975/cagsb.2018.101602 Acta Geoscientica Sinica 39 Science Press 679-690 School of Geophysics and Information Technology, China University of Geosciences, Beijing, 100083, China; Key Laboratory of Geo-detection (China University of Geosciences, Beijing), Ministry of Education, Beijing, 100083, China; Development and Research Center, China Geological Survey, Beijing, 100037, China; Tianjin Branch, CNPC Logging, Tianjin, 300280, China 6 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85063251207&doi=10.3975%2fcagsb.2018.101602&partnerID=40&md5=45febe1702a40b19d1c66b6e33eedce2 cited By 8 C.-C. Zou X.-H. Zhang J.-H. Zhao C. Peng S.-X. Zhang N. Li L. Xiao Y.-X. Niu Y.-J. Ding Y.-X. Qin F. Lin conference Bullock2018 Acoustic image logs from a borehole located at Kimama, Idaho in the Snake River Province were interpreted using WellCAD™ to match and generate orientation data of the natural fractures intersected. One well known problem with such data, however, is the bias imposed towards perpendicular features from linear ‘scanline’ sampling along the borehole axis. This leads to an inaccurate representation of the one-dimensional (1-D) fracture intensity (P10). To correct for this bias, the methodology relies on the assumption that the borehole is truly vertical. An analysis using the Terzaghi, 1965 correction gives 3% of all fracture orientations to be sub-parallel, 41% sub-horizontal and to demonstrate a uniform-biased distribution. The Fouché, 2004 correction yields the highest weighting factor of ~ 9 for a sub-parallel set, in comparison to ~ 14 using the Terzaghi, 1965 method. The chi-squared (χ2) test proves independence between observed and expected fracture distributions. The Kolmogorov-Smirnov (two-sample KS) test shows a substantial mismatch between the cumulative distribution functions (cdf) of the observed and modeled distribution for any sample chosen from the population. Results corroborate the scanline theory, but despite stronger theoretical justifications these methods do not substantially change the corrected statistics for the borehole. Copyright © 2018 ARMA, American Rock Mechanics Association. 2018 English 52nd U.S. Rock Mechanics/Geomechanics Symposium American Rock Mechanics Association (ARMA) Department of Physics, UWI, Trinidad and Tobago; Inst. for Geophysical Research, Dept. of Physics, University of Alberta, Edmonton, AB T6G 2E1, Canada; Earth, Atmospheric, and Planetary Sciences Department, Purdue University, West Lafayette, IN, United States Boreholes; Distribution functions; Rock mechanics; Well logging, Cumulative distribution function; Fracture distributions; Fracture orientations; Kolmogorov-Smirnov; Natural fracture; Orientation data; Snake river plains; Weighting factors, Fracture https://www.scopus.com/inward/record.uri?eid=2-s2.0-85053479689&partnerID=40&md5=78f964ad4595927ac06aa7f8aa594859 cited By 0 E.A.L. Bullock I. Haraksingh article qu2018sample 2018 Precambrian Research 315 Elsevier 222--231 Yuangao Qu Aivo Lepland Mark A Zuilen Martin Whitehouse Alenka E {\v{C}}rne Anthony E Fallick article Levy2018127 The chemical composition and δ37Cl of pore fluids from the ICDP core drilled in the deepest floor of the terminal and hypersaline Dead Sea, and halites from the adjacent Mount Sedom salt diapir, are used to establish the dynamics of halite precipitation and dissolution during the last interglacial and glacial periods. Between ∼132 and 116 thousand years ago (ka) halites precipitated in the lake resulting in the expulsion of Na+ and Cl− from the residual solution. Over 50% of the Cl− reservoir was removed, resulting in a decrease in the Na/Cl ratio from 0.57 to 0.19. This process was accompanied by a decrease in δ37Cl values in the precipitating halites and the associated residual Cl− in the lake. The observed decrease fits a Rayleigh distillation curve with a fractionation factor of Δ(NaCl–Dead Sea solution) = +0.32‰ (±0.12) determined in the present study. This behavior implies negligible contribution of external sources of Cl− to the lake during the main peak of the last interglacial, MIS5e. Subsequently, during the last glacial (ca. 117 to 17 ka) dissolution of halite took place, the Na+ and Cl− inventory were replenished, accompanied by an increase in Na/Cl from 0.21 to 0.55 and in the δ37Cl values from −0.46‰ to −0.12‰. While the lake underwent significant dilution during that time, the decrease in salinity was somewhat suppressed by the dissolution of the halite which was mostly derived from Mount Sedom salt diapir. © 2018 Elsevier B.V. 2018 English 0012821X 10.1016/j.epsl.2018.02.003 Earth and Planetary Science Letters 487 Elsevier B.V. 127-137 Department of Geological and Environmental Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel; Geological Survey of Israel, 30 Malkhe Israel St., Jerusalem, 95501, Israel; Department of Hydrology and Microbiology, Zuckerberg Center, Ben-Gurion University of the Negev, Sede Boker, Israel; Institute of Earth Sciences, The Hebrew University, Givat Ram, Jerusalem, 91904, Israel; Lamont-Doherty Earth Observatory, 61 Route 9W, PO Box 1000, Palisades, NY 10964, United States Curve fitting; Dissolution; Distillation; Glacial geology; Lakes; Precipitation (chemical); Reservoirs (water); Salt tectonics; Sodium chloride, Chemical compositions; Dead sea; Fractionation factors; ICDP; Rayleigh distillation; Residual solutions; Salt diapirs; Salt precipitation, Chloride minerals, chemical composition; chlorine isotope; dissolution; fluid composition; fractionation; halite; hydrochemistry; precipitation (chemistry); Quaternary; reservoir; salt dome, Dead Sea; Israel; Mount Sedom; Southern District https://www.scopus.com/inward/record.uri?eid=2-s2.0-85044732582&doi=10.1016%2fj.epsl.2018.02.003&partnerID=40&md5=8a760a5d05440b5ab1ac90c44f9796dd cited By 13 E.J. Levy Y. Yechieli I. Gavrieli B. Lazar Y. Kiro M. Stein O. Sivan article Riller2018511 Large meteorite impact structures on the terrestrial bodies of the Solar System contain pronounced topographic rings, which emerged from uplifted target (crustal) rocks within minutes of impact. To flow rapidly over large distances, these target rocks must have weakened drastically, but they subsequently regained sufficient strength to build and sustain topographic rings. The mechanisms of rock deformation that accomplish such extreme change in mechanical behaviour during cratering are largely unknown and have been debated for decades. Recent drilling of the approximately 200-km-diameter Chicxulub impact structure in Mexico has produced a record of brittle and viscous deformation within its peak-ring rocks. Here we show how catastrophic rock weakening upon impact is followed by an increase in rock strength that culminated in the formation of the peak ring during cratering. The observations point to quasi-continuous rock flow and hence acoustic fluidization as the dominant physical process controlling initial cratering, followed by increasingly localized faulting. © 2018, Springer Nature Limited. 2018 10.1038/s41586-018-0607-z Nature 562 511-518 Institut für Geologie, Universität Hamburg, Hamburg, Germany; Department of Geology, Universität Freiburg, Freiburg, Germany; Department of Earth Science and Engineering, Imperial College London, London, United Kingdom; Department of Earth, Atmospheric and Planetary Sciences, Purdue University, West Lafayette, IN, United States; Centre for Planetary Science and Exploration, Western University, London, ON, Canada; Institute for Geophysics, University of Texas, Austin, TX, United States; Department of Geological Sciences, Jackson School of Geosciences, University of Texas, Austin, TX, United States; Géosciences Montpellier, CNRS, Université de Montpellier, Montpellier, France; Universities Space Research Association, Lunar and Planetary Institute, Houston, TX, United States; British Geological Survey, The Lyell Centre, Research Avenue South, Edinburgh, United Kingdom; Université de Bourgogne-CNRS, Biogeosciences Laboratory, Dijon, France; Analytical, Environmental and Geochemistry (AMGC), Vrije Universiteit Brussel (VUB), Brussels, Belgium; School of Physics and Astronomy, UK Center for Astrobiology, University of Edinburgh, Edinburgh, United Kingdom; Western Australia Organic and Isotope Geochemistry Centre, School of Earth and Planetary Sciences, Curtin University, Bentley, WA, Australia; Natural History Museum, Vienna, Austria; Alfred Wegener Institute Helmholtz Centre of Polar and Marine Research, Bremerhaven, Germany; International Research Institute of Disaster Science, Tohoku University, Sendai, Japan; Pennsylvania State University, University Park, PA, United States; China University of Geosciences (Wuhan), School of Earth Sciences, Planetary Science Institute, Wuhan, China; National Center of Scientific Research (CNRS), Groupe de Physico-Chimie de l’Atmosphère, Institut de Chimie et Procédés pour l’Energie, l’Environnement et la Santé ICPEES, Université de Strasbourg, Strasbourg, France; Instituto de Geofísica, Universidad Nacional Autónoma De México, México City, Mexico; School of Geographical and Earth Sciences, University of Glasgow, Glasgow, United Kingdom; Argon Isotope Facility, Scottish Universities Environmental Research Centre (SUERC), East Kilbride, United Kingdom; Department of Geology, University of Freiburg, Freiburg, Germany; Department of Earth Science and Engineering, Imperial College London, London, United Kingdom; Unidad de Ciencias del Agua, Mérida, Mexico; Japan Agency for Marine-Earth Science and Technology, Yokosuka, Japan; Faculty of Earth and Life Sciences, Amsterdam, Netherlands; Earth and Planetary Sciences, Rutgers University—New Brunswick, Piscataway, NJ, United States; Japan Agency for Marine-Earth Science and Technology, Kochi Institute for Core Sample Research, Kochi, Japan; Department of Geosciences, University of Alaska Fairbanks, Fairbanks, AK, United States; Eyring Materials Center, Arizona State University, Tempe, AZ, United States; Department of Chemistry, Tohu University, Funabashi, Japan; NASA Astrobiology Institute, Mountain View, CA, United States 7728 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85055416559&doi=10.1038%2fs41586-018-0607-z&partnerID=40&md5=53993392074e42eeda2f50f11a27862e cited By 52 U. Riller M.H. Poelchau A.S.P. Rae F.M. Schulte G.S. Collins H.J. Melosh R.A.F. Grieve J.V. Morgan S.P.S. Gulick J. Lofi A. Diaw N. McCall D.A. Kring S.L. Green E. Chenot G.L. Christeson P. Claeys C.S. Cockell M.J.L. Coolen L. Ferrière C. Gebhardt K. Goto H. Jones L. Xiao C.M. Lowery R. Ocampo-Torres L. Pérez-Cruz A.E. Pickersgill C. Rasmussen M. Rebolledo-Vieyra H. Sato J. Smit S.M. Tikoo-Schantz N. Tomioka M.T. Whalen A. Wittmann K. Yamaguchi T.J. Bralower J.U. Fucugauchi IODP-ICDP Expedition 364 Science Party article Gupta20182907 Reservoir triggered seismicity (RTS) is an anthropogenic effect of creating artificial water reservoirs. Worldwide, the biggest RTS earthquake of magnitude M 6.3 occurred on 10 December 1967 at Koyna, India. From among RTS sites globally, at four sites destructive earthquakes exceeding magnitude 6 occurred. RTS at Koyna has continued until now, whereas at other sites it ceased in a year to a few years. Detailed studies of RTS sequences carried out in 1970s led to delineating common characteristics of RTS events that also help in differentiating RTS sequences from normal earthquake sequences. Association of water level changes in the Koyna and Warna reservoirs and RTS in the Koyna region has been well established. The part played by reservoirs in triggering the earthquakes is not well understood, due to lack of near-field studies. Koyna is found to be a very suitable site for such studies. The suitability of the Koyna site for setting up a deep borehole laboratory and the scientific work to be carried out were discussed in an International Continental Drilling Program (ICDP) supported workshop held in India in 2011. The suggested additional work to be carried out was undertaken from 2011 to 2014 and discussed in the second ICDP Workshop held in 2014. A go-ahead was given for putting up a pilot borehole of 3000-m depth. The pilot borehole drilling started in December 2016 and was completed in June 2017, along with necessary observations and studies. These were presented in the Post Operation Workshop held during October 2017. A few salient features of the work carried out in the last 50 yrs are presented here. © 2018, Seismological Society of America. All rights reserved. 2018 English 00371106 10.1785/0120180019 Bulletin of the Seismological Society of America 108 Seismological Society of America 2907-2918 National Geophysical Research Institute, Uppal Road, Hyderabad, 500007, India 5 Boreholes; Boring; Infill drilling; Reservoirs (water); Water levels, Anthropogenic effects; Artificial water; Borehole drilling; Deep boreholes; Earthquake sequences; Near field study; Salient features; Water level changes, Earthquakes, anthropogenic effect; earthquake magnitude; earthquake trigger; reservoir-induced seismicity; trigger mechanism; water level, India; Koyna; Maharashtra https://www.scopus.com/inward/record.uri?eid=2-s2.0-85057109687&doi=10.1785%2f0120180019&partnerID=40&md5=9c1077f5068caebf048d7ae583f482c2 cited By 19 H.K. Gupta article liwei2018research 2018 CHINA MINING MAGAZINE 27 China Mining Magazine Co., Ltd 159-163 8 CUI Liwei ZHANG Chenguang ZHANG Sujiang JIANG Ailing LIU Guiyun article Liu2018 The Cheb Basin (CZ) is a shallow Neogene intracontinental basin filled with fluvial and lacustrine sediments that is located in the western part of the Eger Rift. The basin is situated in a seismically active area and is characterized by diffuse degassing of mantle-derived CO2 in mofette fields. The Hartoušov mofette field shows a daily CO2 flux of 23-97 tons of CO2 released over an area of 0.35 km2 and a soil gas concentration of up to 100% CO2. The present study aims to explore the geo-bio interactions provoked by the influence of elevated CO2 concentrations on the geochemistry and microbial community of soils and sediments. To sample the strata, two 3-m cores were recovered. One core stems from the center of the degassing structure, whereas the other core was taken 8 m from the ENE and served as an undisturbed reference site. The sites were compared regarding their geochemical features, microbial abundances, and microbial community structures. The mofette site is characterized by a low pH and high TOC/sulfate contents. Striking differences in the microbial community highlight the substantial impact of elevated CO2 concentrations and their associated side effects on microbial processes. The abundance of microbes did not show a typical decrease with depth, indicating that the uprising CO2-rich fluid provides sufficient substrate for chemolithoautotrophic anaerobic microorganisms. Illumina MiSeq sequencing of the 16S rRNA genes and multivariate statistics reveals that the pH strongly influences microbial composition and explains around 38.7% of the variance at the mofette site and 22.4% of the variance between the mofette site and the undisturbed reference site. Accordingly, acidophilic microorganisms (e.g., OTUs assigned to Acidobacteriaceae and Acidithiobacillus) displayed a much higher relative abundance at the mofette site than at the reference site. The microbial community at the mofette site is characterized by a high relative abundance of methanogens and taxa involved in sulfur cycling. The present study provides intriguing insights into microbial life and geo-bio interactions in an active seismic region dominated by emanating mantle-derived CO2-rich fluids, and thereby builds the basis for further studies, e.g., focusing on the functional repertoire of the communities. However, it remains open if the observed patterns can be generalized for different time-points or sites. © 2018 Frontiers Media S.A. All Rights Reserved. Article 2018 English 1664302X 10.3389/fmicb.2018.02787 Frontiers in Microbiology 9 Frontiers Media S.A. NOV carbon dioxide; RNA 16S; Acidithiobacillus; amplicon; Article; bioinformatics; DNA extraction; DNA purification; dsrB gene; gasification; gene; gene amplification; geochemical analysis; microbial community; nonhuman; pH; population abundance; real time polymerase chain reaction; stratigraphy https://www.scopus.com/inward/record.uri?eid=2-s2.0-85057591088&doi=10.3389%2ffmicb.2018.02787&partnerID=40&md5=9c203f01ec923ff7eee0334137edc18b Cited by: 4; All Open Access, Gold Open Access, Green Open Access Qi Liu Horst Kämpf Robert Bussert Patryk Krauze Fabian Horn Tobias Nickschick Birgit Plessen Dirk Wagner Mashal Alawi article kelemen2018situ 2018 Energy Procedia 146 Elsevier 92--102 Peter B Kelemen Roger Aines Emma Bennett Sally M Benson Emma Carter Jude A Coggon Juan C De Obeso Ondati Evans Greeshma Gadikota Gregory M Dipple others article Kousis201820 To better understand climate variability during Marine Isotope Stage (MIS) 11, we here present a new, centennial-scale-resolution pollen record from Lake Ohrid (Balkan Peninsula) derived from sediment cores retrieved during an International Continental Scientific Drilling Program (ICDP) campaign. Our palynological data, augmented by quantitative pollen-based climate reconstructions, provide insight into the vegetation dynamics and thus also climate variability in SE Europe during one of the best orbital analogues for the Holocene. Comparison of our palynological results with other proxy data from Lake Ohrid as well as with regional and global climate records shows that the vegetation in SE Europe responded sensitively both to long- and short-term climate change during MIS 11. The chronology of our palynological record is based on orbital tuning, and is further supported by the detection of a new tephra from the Vico volcano, central Italy, dated to 410 ± 2 ka. Our study indicates that MIS 11c (∼424–398 ka) was the warmest interval of MIS 11. The younger part of the interglacial (i.e., MIS 11b–11a; ∼398–367 ka) exhibits a gradual cooling trend passing over into MIS 10. It is characterized by considerable millennial-scale variability as inferred by six abrupt forest-contraction events. Interestingly, the first forest contraction occurred during full interglacial conditions of MIS 11c; this event lasted for ∼1.7 kyrs (406.2–404.5 ka) and was characterized by substantial reductions in winter temperature and annual precipitation. Most notably, it occurred ∼7 ka before the end of MIS 11c and ∼15 ka before the first strong ice-rafted debris event in the North Atlantic. Our findings suggest that millennial-scale climate variability during MIS 11 was established in Southern Europe already during MIS 11c, which is earlier than in the North Atlantic where it is registered only from MIS 11b onwards. © 2018 Elsevier Ltd Article 2018 English 02773791 10.1016/j.quascirev.2018.04.014 Quaternary Science Reviews 190 Elsevier Ltd 20 – 38 Paleoenvironmental Dynamics Group, Institute of Earth Sciences, Heidelberg University, Im Neuenheimer Feld 234, Heidelberg, 69120, Germany; ISEM, Université de Montpellier, CNRS, IRD, EPHE, Montpellier, France; Institute of Geology and Mineralogy, University of Cologne, Zülpicher Str. 49a, Cologne, 50674, Germany; Wollongong Isotope Geochronology Laboratory, School of Earth and Environmental Sciences, University of Wollongong, Wollongong, NSW 2522, Australia; Istituto di Geologia Ambientale e Geoingegneria, CNR, Via Salaria km 29.300, Monterotondo, Rome 00115, Italy; Institute of Botany, University of Hohenheim, Garbenstr. 30, Stuttgart, 70599, Germany Atlantic Ocean; Atlantic Ocean (North); Balkans; Europe; Italy; Lake Ohrid; Lazio; Mediterranean Sea; Mediterranean Sea (East); Vico; Forestry; Glacial geology; Isotopes; Lakes; Repair; Vegetation; Abrupt climate change; Balkan peninsulas; Climate reconstruction; Eastern Mediterranean; Lake Ohrid; Marine isotope stages; Southern Europe; Tephrostratigraphy; Terrestrial ecosystems; Vico tephra; chronology; climate change; climate variation; global climate; ice-rafted debris; interglacial; marine isotope stage; paleoclimate; palynology; pollen; precipitation (climatology); reconstruction; sediment core; tephra; vegetation dynamics; Climate change https://www.scopus.com/inward/record.uri?eid=2-s2.0-85046695082&doi=10.1016%2fj.quascirev.2018.04.014&partnerID=40&md5=2a8dbba5b3964f7538e927c2b5a27bcb Cited by: 28 Ilias Kousis Andreas Koutsodendris Odile Peyron Niklas Leicher Alexander Francke Bernd Wagner Biagio Giaccio Maria Knipping Jörg Pross article honghao2018characteristics 2018 Global Geology 37 838-849 3 Li Honghao WangPujun GaoYoufeng Qu Xuejiao Gao Xiang Chen Haichao article Hou2018173 The Songke No.2 well (eastern hole) (referred to as Well SK-2), one of the “two wells and four holes” of the Deep Continental Scientific Drilling Engineering Project in the Songliao Basin, is in Anda City, Heilongjiang Province, and was officially completed on May 26, 2018. The scientific goals of Well SK-2 cover four aspects: paleoclimate research, resource and energy exploration, primary geological research, and development of deep earth exploration techniques. Since the official commencement of drilling in 2014, the Well SK-2 scientific drilling engineering team has organized and implemented drilling for coring, in situ logging, chemical analysis of core elements, and deep structural exploration around the well. Currently, the following preliminary scientific research progress has been made: 4334.81 m in situ core data has been obtained; the centimeter-level high-resolution characterization of the most complete and continuous Cretaceous continental strata ever unearthed has been completed, and the standard profile of continental strata has been initially established; the unconventional natural gas resources and basin-type hot dry rocks in the deep Songliao Basin were found to have good prospects for exploration and development; the climatic evolutionary history of the Cretaceous continental strata was rebuilt for the first time, covering hundreds of thousands to millions of years, and the major events of Cretaceous climate fluctuations have been discovered; all these reveal strong evidence for the subduction and aggregation of paleo-ocean plates, providing a theoretical basis for the re-recognition of the genesis of the Songliao Basin and for deep earth oil and gas exploration. The implementation of the Deep Continental Scientific Drilling Engineering Project in the Songliao Basin is of great significance for exploring the mysteries of the Earth and solving major problems such as those related to the deep energy environment. It is a solid step along the road of “going deep into the Earth”. © 2019 Elsevier B.V. 2018 English 20965192 10.31035/cg2018036 China Geology 1 KeAi Communications Co. 173-186 Chinese Academy of Geological Sciences, Beijing, 100037, China; China University of Geosciences (Beijing), Beijing, 100083, China; Oil and Gas Survey, China Geological Survey, Beijing, 100029, China; Institute of Hydrogeology and Environmental Geology, Chinese Academy of Geological Sciences, Shijiazhuang, 050061, China; Jilin University, Changchun, 130061, China 2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85065516061&doi=10.31035%2fcg2018036&partnerID=40&md5=4001a447c813e987664861372f67d206 cited By 16 H.-S. Hou C.-S. Wang J.-D. Zhang F. Ma W. Fu P.-J. Wang Y.-J. Huang C.-C. Zou Y.-F. Gao Y. Gao L.-M. Zhang J. Yang R. Guo article Hou2018641 The eastern borehole of Well SK-2, among the "two wells and four boreholes" of the deep continental scientific drilling engineering in Songliao Basin, is situated in Anda of Heilongjiang Province and was finished officially on May 26th, 2018. Well SK- 2 mainly focused on four scientific objections, i.e., paleoclimate research, resource and energy exploration, basic geological research and development of deep exploration technology. During the process if drilling which began in 2014, drilling, coring, logging, analysis of chemical element and structural exploration of surrounding areas were carried out during the SK-2 drilling engineering, and some preliminary progresses were made in scientific research: 4134.8 m-long in-situ core data were acquired, and the most complete and continuous continental strata of the cretaceous were described with high resolution of centimeter-level, thus building the standard continental stratigraphic profile. Besides, evolution history of the continental facies in the Cretaceous period from scale of one million to one hundred thousand years was reconstructed for the first time, and an important climatic event of the Cretaceous was found. Apart from these achievements, evidence of Paleo- Pacific plate subduction and convergence in the deep was found, which contributes to genetic re- recognition and deep hydrocarbon exploration in Songliao basin. The implementation of deep continental scientific drilling engineering in Songliao Basin is of great significance in exploring the earth's mystery, seeking for deep energy and solving environmental problems. It is considered to be a solid step in the way of heading deep of the earth. © 2018 Editorial Board of Geology in China. All rights reserved. 2018 Chinese 10003657 10.12029/gc20180401 Geology in China 45 Editorial Board of Geology in China 641-657 Chinese Academy of Geological Sciences, Beijing, 100037, China; China University of Geosciences, Beijing, J00083, China; Center for Oil and Gas Survey, China Geological Survey, Beijing, 100029, China; Institute of Hydrogeology and Environmental Geology, Chinese Academy of Geological Science, Shijiazhuang, Hebei, 050061, China; Jilin University, Changchun, Jilin, 130061, China 4 Cretaceous; drilling; Earth science; energy resource; geographical research; hydrocarbon exploration; Pacific plate; paleoclimate, China; Heilongjiang; Songliao Basin https://www.scopus.com/inward/record.uri?eid=2-s2.0-85057354737&doi=10.12029%2fgc20180401&partnerID=40&md5=4e339ad6ddf185c45fada1bc89a5069f cited By 33 H. Hou C. Wang J. Zhang F. Ma W. Fu P. Wang Y. Huang C. Zou Y. Gao L. Zhang J. Yang R. Guo article Zhang2018271 Evaluating the terrestrial climate record provides a critical test of the roles of Chicxulub impact and Deccan Traps volcanism during the Cretaceous-Paleogene (K-Pg) mass extinction. Most evidence came from marine records, but our new clumped isotopes data from paleosol carbonates in the Songliao Basin provide a terrestrial climate history from northern China. This reveals there was a pre-impact warming caused by the onset of Deccan Traps volcanism, whereas the following short-term cooling then another warming episode were likely caused by Chicxulub impact and post-boundary volcanism. Our study suggests that the pCO2 levels were probably the main control on the latest Cretaceous cooling and the climatic fluctuations across the K-Pg boundary interval in northern China. In the Songliao Basin, the pre-impact Deccan Traps volcanism links to losses of half of the lacustrine algae species (charophytes) and almost all of the lacustrine ostracodes; this suggests that the Deccan Traps volcanism had already destabilized the ecosystem and caused extinctions prior to the Chicxulub impact. © 2018 Geological Society of America. 2018 English 00917613 10.1130/G39992.1 Geology 46 Geological Society of America 271-274 State Key Laboratory of Biogeology and Environmental Geology, School of Earth Sciences and Resources, China University of Geosciences Beijing, Beijing, 100083, China; School of Earth and Environment, University of Leeds, Leeds, LS2 9JT, United Kingdom; Institut für Umweltphysik, Universität Heidelberg, Im Neuenheimer Feld 229, Heidelberg, 69120, Germany; School of Energy Resources, China University of Geosciences Beijing, Beijing, 100083, China; China Huadian Green Energy Co., Ltd., Beijing, 100160, China 3 Chicxulub impact; Climate history; Climate record; Climatic fluctuations; Clumped isotopes; K-pg boundaries; Mass extinction; Temperature rise, Geology, carbon dioxide; Cretaceous-Paleogene boundary; mass extinction; paleosol; volcanism, China; Songliao Basin, algae; Characeae; Ostracoda https://www.scopus.com/inward/record.uri?eid=2-s2.0-85042492280&doi=10.1130%2fG39992.1&partnerID=40&md5=2f756317e1b69f427cbcc79b166f59ef cited By 40 L. Zhang C. Wang P.B. Wignall T. Kluge X. Wan Q. Wang Y. Gao article Chen201815 The paleoclimate of the southern Levant, especially during the last interglacial (LIG), is still under debate. Reliable paleovegetation information for this period, as independent evidence to the paleoenvironment, was still missing. In this study, we present a high-resolution pollen record encompassing 147–89 ka from the Dead Sea deep drilling core 5017-1A. The sediment profile is marked by alternations of laminated marl deposits and thick massive halite, indicating lake-level fluctuations. The pollen record suggests that steppe and desert components predominated in the Dead Sea surroundings during the whole investigated interval. The late penultimate glacial (147.3–130.9 ka) and early last glacial (115.5–89.1 ka) were cool and relatively dry, with sub-humid conditions confined to the mountains that sustained moderate amounts of deciduous oaks. Prior to the LIG optimum, a prevalence of desert components and a concomitant increase in frost-sensitive pistachio trees demonstrate the occurrence of an arid initial warming phase (130.9–124.2 ka). The LIG optimum (124.2 ka–115.5 ka) was initiated by an abrupt grass expansion that was followed by a rapid spread of woodlands in the mountains due to increased moisture availability. The remarkable sclerophyllous expansion points to a strong seasonal moisture deficit. These results contradict previous Dead Sea lake-level investigations that suggested pluvial glacials and a warm, dry LIG in the southern Levant. Prominent discrepancies between vegetation and Dead Sea lake stands are also registered at 128–115 ka, and the potential causes are discussed. In particular, while the pollen spectra mirror increased effective moisture during the LIG optimum, the massive halite deposition is indicative of an extremely low lake level. Given that the climate amelioration triggered the migration of early modern humans to the southern Levant, we speculate that the diverse ecosystems in the region provided great potential for their residence. Across the eastern Mediterranean region, an analogous vegetation succession pattern is observed. © 2018 Elsevier Ltd 2018 English 02773791 10.1016/j.quascirev.2018.03.029 Quaternary Science Reviews 188 Elsevier Ltd 15-27 School of Geographic Science, Nantong University, Tongjingdadao 999, Nantong, 226007, China; Steinmann Institute for Geology, Mineralogy, and Paleontology, University of Bonn, Nussallee 8, Bonn, 53115, Germany Chloride minerals; Fertilizers; Glacial geology; Landforms; Moisture; Sodium chloride; Vegetation, Eastern Mediterranean; Human migration; Lake levels; Last interglacial; Paleovegetation, Lakes, deciduous tree; deep drilling; desert; dicotyledon; grass; interglacial; lake level; Last Glacial; marine isotope stage; migration; paleobotany; paleoclimate; paleoenvironment; pollen; sediment analysis; steppe; warming, Dead Sea; Levant; Mediterranean Region; Mediterranean Sea; Mediterranean Sea (East), Pistacia vera; Quercus https://www.scopus.com/inward/record.uri?eid=2-s2.0-85044538478&doi=10.1016%2fj.quascirev.2018.03.029&partnerID=40&md5=aed38a4736053656daf09d63e32f0ce6 cited By 23 C. Chen T. Litt article Masotta2018603 Article 2018 10.1016/j.chemgeo.2018.03.031 Chemical Geology 483 603 – 618 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85044331691&doi=10.1016%2fj.chemgeo.2018.03.031&partnerID=40&md5=60aad59f566190ef80223f2e1f62cc14 Cited by: 21 M. Masotta S. Mollo M. Nazzari V. Tecchiato P. Scarlato P. Papale O. Bachmann article Iovine2018199 The origin of large variations in stable and radiogenic isotope compositions of magmas erupted from the Neapolitan volcanoes, including Somma-Vesuvius and Campi Flegrei (Southern Italy), has always been contentious. Indeed, the role and relative importance of sediment subduction versus crustal assimilation to explain the chemical and isotopic variations of the erupted magmas remain unclear. Isotopic disequilibrium between minerals and their host indicate that bulk rock analyses are incapable of constraining the isotopic composition of the source. Therefore, we use isotopic (87Sr/86Sr, 18O/16O and 17O/16O) data on separated minerals (feldspar, clinopyroxene and olivine phenocrysts) from pyroclastic successions and lava flows of the Neapolitan volcanic area (Phlegrean Volcanic District and Somma-Vesuvius complex) to better constrain magmatic oxygen and strontium isotope ratios. Magmatic values recalculated from δ18O of olivine and clinopyroxene phenocrysts range from typical mantle values of 5.2‰ to almost 9‰ relative to SMOW. These compositions are very different from those of typical mantle sources. In order to assess the degree of magma evolution from which these minerals formed, the Mg# of clinopyroxene and olivine were converted into host melt Mg#, resulting in the range 44 to 76. Simple assimilation of silicic crustal rocks is difficult to reconcile with the mafic nature of these estimated host magma compositions. This indicates that some mafic, mantle-derived magmas, having unusually heavy oxygen isotope (up to ~9‰) and high Sr isotope compositions (0.7050 to 0.7085), must exist. Crustal assimilation of carbonates can be excluded by the lack of a link between isotopes and major and trace element signatures. Assimilation of either Hercynian-like crust or altered pyroclastic rocks, however, cannot be ruled out completely. However, assimilation of partial melts from a Hercynian-like crust would have to be ~12% and ~21% to explain the heavy oxygen isotope values of Campi Flegrei and Somma-Vesuvius, respectively. Such degrees of assimilation are unlikely since the magmas are either too mafic or too alkaline to be consistent with such high proportion of crustal components. Other, less mafic Campi Flegrei, Somma-Vesuvius and Ischia magmas with more typical mantle oxygen isotopes, have been possibly generated in a mantle source affected by minor contamination by pelagic and carbonate sediments and subsequent assimilation of Hercynian-like crust. Sr-O mixing models indicate that such magmas were derived from a mantle source that was contaminated by up to 10% of a 1:1 mixture of pelagic and carbonate sediments. These findings together demonstrate the highly complex and varied magma sources in the Campania volcanic district. Triple oxygen isotope variations (Δ17O), based on measurements of both 18O/16O and 17O/16O ratios in potential assimilants are in agreement with these conclusions. © 2018 Elsevier B.V. Article 2018 English 00244937 10.1016/j.lithos.2018.07.009 Lithos 316-317 Elsevier B.V. 199 – 211 Campania [Italy]; Campi Flegrei; Italy; Napoli [Campania]; Somma Vesuviana; crustal structure; isotopic composition; magma; mantle structure; oxygen isotope; stable isotope; strontium isotope; volcano https://www.scopus.com/inward/record.uri?eid=2-s2.0-85050411758&doi=10.1016%2fj.lithos.2018.07.009&partnerID=40&md5=0e67c676db2437953c38d6bef5247413 Cited by: 12 Raffaella Silvia Iovine Fabio Carmine Mazzeo Gerhard Wörner Carlo Pelullo Gianluca Cirillo Ilenia Arienzo Andreas Pack Massimo D'Antonio article Konno2018662 The authors would like to replace the section 1. 1ntroduction (pp. 425) with the following: Introduction Methane hydrate, which is a crystalline compound formed from methane and water, is found in arctic and marine continental margin sediments worldwide (Sloan and Koh, 2008). The P-wave velocity of hydrate-bearing sediments is higher than that of hydrate-free unconsolidated sediments (e.g., Yuan et al., 1996), and laboratory experiments have shown that there is a strong relationship between the P-wave velocity and hydrate saturation (e.g., Berge et al., 1999). Through the comparison with model predictions such as those of Dvorkin et al. (2000), it was found that this relationship depends on the hydrate morphology, such as grain coating, cementing, pore-filling, and sediment frame component (or load-bearing) within the pore space (M. Lee et al., 1996; Berge et al., 1999; Reister, 2003; Yun et al., 2005; Priest et al., 2009; J. Lee et al., 2010; Hu et al., 2010, Li et al., 2011; Best et al., 2013; Kim et al., 2013a). This suggests that the P-wave velocity obtained from logging and seismic surveys can be used to estimate the in situ hydrate saturation if the hydrate morphology in actual reservoirs is revealed. P-wave velocity changes during CH4eCO2 replacement in hydrates have also been studied to estimate the sediment stiffness (Espinoza and Santamarina, 2011; Liu et al., 2013). It is therefore important to understand the relationship between the P-wave velocity, hydrate saturation, and hydrate morphology because these properties are deeply linked to the physical properties of hydrate-bearing sediments, such as their permeability, thermal properties, electrical conductivity, and shear strength (Waite et al., 2009; Santamarina and Ruppel, 2010). Quantitative detection of methane hydrate in natural sediments has been attempted over the years. Wood et al. (1994) analyzed seismic interval velocities at the Blake Ridge for quantitative detection of methane hydrate. Chand et al. (2004) compared P- wave velocities predicted by four models and field data from the Mallik field in the Mackenzie Delta and the Blake Ridge. At the Mallik field, Carcione and Gei (2004) estimated hydrate saturation from well logging data and vertical seismic profiles by assuming that the hydrate filled pore space (pore-filling). Dash and Spence (2011) estimated hydrate saturation at the northern Cascadia margin using P-wave and S-wave velocities. They concluded that the hydrate is distributed as part of the load-bearing matrix. For other areas, such as the Nankai Trough, Mount Elbert, the KrishnaeGodavari basin, the Tsushima Basin, and the Shenhu area of the South China Sea, estimations of hydrate saturation have also been conducted (Inamori et al., 2010; Lee and Collett, 2011; Kim et al., 2013b; Shankar and Riedel, 2011; Lee and Collett, 2013; Wang et al., 2014). Hydrate morphology was estimated as load-bearing at the Nankai Trough, Mount Elbert, and the KrishnaeGodavari basin, whereas it was estimated to be pore-filling at the Tsushima Basin. Winters et al. (2004) reported that the mildly-disturbed samples recovered from the 2L-38 well at the Mallik field are best modeled as part of the sediment frame (load-bearing). Laboratory experiments using artificial cores have also provided insight into the relationship between P-wave velocity and hydrate saturation; however, there are some limitations to the use of artificial cores in estimating hydrate saturation in natural sediments. One of the reasons is that it is difficult to control hydrate morphology in such a way as to mimic natural features in artificial cores. Hydrate formed in a gas-rich environment, which is a conventional method used in laboratory studies, generally shows a cementing morphology (Winters et al., 2004; Priest et al., 2005, 2006). In contrast, hydrate formed from methane dissolved in the pore fluid, which is considered as common in natural environments, may not show a cementing morphology (Spangenberg et al., 2005, 2008; Winters et al., 2007). Using a non-methane hydrate former, Yun et al. (2005) and Lee et al. (2010) documented a transition between pore-filling and load-bearing hydrates at saturation of ~40%e50% of pore space. Gas hydrate morphology in natural sediments is depends on the hydrate occurrence mechanism; however, it is difficult to know the occurrence mechanism for each reservoir. Analysis of logging data seems to be effective in estimating the actual relationship between P-wave velocity, hydrate saturation, and hydrate morphology in natural sediments. However, the spatial resolution of P-wave velocity data and hydrate saturation data, as estimated from resistivity logging, is larger than that of core data, and the various datasets are not usually entirely coincident. Thus, cross-plots of P- wave velocity and hydrate saturation are often so scattered that it is difficult to accurately constrain the hydrate morphology. In addition, the frequency used for in situ exploration is much lower than that used in laboratory experiments, which results in differences in the depth and spatial resolution of measurements. In situ exploration data are spatially-averaged and appropriate for the determination of the hydrate distribution in bulk sediments. However, such data are difficult to apply to the investigation of local properties, such as the pore space hydrate morphology. Consequently, high frequency laboratory experiments using natural sediments are more favorable for the analysis of pore space hydrate morphology. Pressure core analysis technologies now enable the study of relatively undisturbed samples recovered from hydrate-bearing natural sediments, and pressure core analyses of P-wave veloc ities have been conducted for hydrate-bearing natural sediments (Yun et al., 2006, 2010, 2011; Schultheiss et al., 2011). Lee et al. (2013) successfully determined the relationship between P-wave velocity and hydrate saturation from pressure cores recovered from the Tsuhima Basin. They concluded that the hydrate morphology is pore-filling at low hydrate saturations, but gradually deviates from pore-filling toward cementation as hydrate saturation increases, in accordance with studies of Yun et al. (2005) and Lee et al. (2010). They used the Pressure Core Analysis and Transfer System (PCATS) developed by Geotek Ltd. (Schultheiss et al., 2011) to measure P- wave velocity through the core liner at high resolution. However, the study noted that the data resolving hydrate saturation was much lower than that of P-wave velocity because hydrate saturation was calculated based on a dissociation experiment conducted on the whole core including both high and low P-wave velocity sections (Lee et al., 2013). In this study, a newly developed pressure core cutting, manipulating, and analyzing system was used to overcome the discrepancy of data resolution between P-wave velocity and hydrate saturation. P-wave velocity was measured by the PCATS at a high resolution using pressure cores recovered from the Eastern Nankai Trough offshore Japan. After the P-wave velocity measurements, the cores were cut into pieces under pressure for separate P-wave velocity intervals on the basis of visual observation enabled by our pressure core system. To obtain high resolution hydrate-saturation data, each sub-sampled core was depressurized and the gas volume was measured. By comparing experimental data with physical model predictions, hydrate morphology in pore space was studied in detail. The authors would like to apologise for any inconvenience caused. DOI of original article: dx.doi.org/10.1016/j.marpetgeo.2015.02.021 © 2018 2018 English 02648172 10.1016/j.marpetgeo.2018.02.022 Marine and Petroleum Geology 91 Elsevier Ltd 662-663 Methane Hydrate Research Center (MHRC), National Institute of Advanced Industrial Science and Technology (AIST), 2-17-2-1 Tsukisamu-Higashi, Toyohira-Ku, Sapporo, 062-8517, Japan; MHRC, AIST, 16-1 Onogawa, Tsukuba, Ibaraki, 305-8569, Japan; Methane Hydrate Research & Development Division, Japan Oil, Gas and Metals National Corporation (JOGMEC), 1-2-2 Hamada, Mihama-ku, Chiba-city, Chiba, 261-0025, Japan https://www.scopus.com/inward/record.uri?eid=2-s2.0-85045074980&doi=10.1016%2fj.marpetgeo.2018.02.022&partnerID=40&md5=691c5d7cc663fa7dc3297ebbbabaf816 cited By 0 Y. Konno Y. Jin J. Yoneda M. Kida K. Egawa T. Ito K. Suzuki J. Nagao article se94692018 Three datasets are used to quantify fracture density, orientation, and fill in the foliated hanging wall of the Alpine Fault: (1) X-ray computed tomography (CT) images of drill core collected within 25gm of its principal slip zones (PSZs) during the first phase of the Deep Fault Drilling Project that were reoriented with respect to borehole televiewer images, (2) field measurements from creek sections up to 500gm from the PSZs, and (3) CT images of oriented drill core collected during the Amethyst Hydro Project at distances of ĝ1/4 g0.7-2gkm from the PSZs. Results show that within 160gm of the PSZs in foliated cataclasites and ultramylonites, gouge-filled fractures exhibit a wide range of orientations. At these distances, fractures are interpreted to have formed at relatively high confining pressures and/or in rocks that had a weak mechanical anisotropy. Conversely, at distances greater than 160gm from the PSZs, fractures are typically open and subparallel to the mylonitic or schistose foliation, implying that fracturing occurred at low confining pressures and/or in rocks that were mechanically anisotropic. Fracture density is similar across the g1/4 g500gm width of the field transects. By combining our datasets with measurements of permeability and seismic velocity around the Alpine Fault, we further develop the hierarchical model for hanging-wall damage structure that was proposed by Townend et al. (2017). The wider zone of foliation-parallel fractures represents an outer damage zone that forms at shallow depths. The distinct g160gm wide interval of widely oriented gouge-filled fractures constitutes an inner damage zone. This zone is interpreted to extend towards the base of the seismogenic crust given that its width is comparable to (1) the Alpine Fault low-velocity zone detected by fault zone guided waves and (2) damage zones reported from other exhumed large-displacement faults. In summary, a narrow zone of fracturing at the base of the Alpine Fault's hanging-wall seismogenic crust is anticipated to widen at shallow depths, which is consistent with fault zone flower structure models. © Author(s) 2018. 2018 English 18699510 10.5194/se-9-469-2018 Solid Earth 9 Copernicus GmbH 469--489 Department of Geology, University of Otago, P.O. Box 56, Dunedin, 9054, New Zealand; School of Geography, Environment, and Earth Sciences, Victoria University of Wellington, P.O. Box 600, Wellington, 6012, New Zealand; GNS Science, P.O. Box 30-368, Lower Hutt, 5040, New Zealand; Department of Earth and Ocean Sciences, NUI Galway, University Road, Galway, Ireland; Department of Computer Science, University of Otago, P.O. Box 56, Dunedin, 9054, New Zealand; School of Earth and Ocean Sciences, Cardiff University, Cardiff, CF10 3AT, United Kingdom 2 Anisotropy; Core drilling; Damage detection; Drills; Fracture; Guided electromagnetic wave propagation; Hierarchical systems; Rock pressure, Fault zone structures; High confining pressure; Large displacements; Low confining pressure; Low velocity zones; Mechanical anisotropy; Parallel fractures; X-ray computed tomography, Computerized tomography, brittle fracture; data set; fault zone; foliation; fracture orientation; hanging wall; permeability; seismic velocity, Alpine Fault Zone; New Zealand; South Island https://se.copernicus.org/articles/9/469/2018/ cited By 13 J. N. Williams V. G. Toy C. Massiot D. D. McNamara S. A. F. Smith S. Mills article Torrente20182283 The paper by De Natale et al. (2016, https://doi.org/10.1002/2015GC006183) reported new stratigraphic and geochronological data for a borehole located at Campi Flegrei volcanic area. The authors failed to mention several significant articles on the geological evolution of the region and proposed an interpretation of their data according to the caldera model. Herein, we provide tectonic and stratigraphic data to support a fault model of ignimbrite emission. This comment will also show the inconsistency of the proposed Campi Flegrei caldera. ©2018. American Geophysical Union. All Rights Reserved. Note 2018 English 15252027 10.1029/2017GC007297 Geochemistry, Geophysics, Geosystems 19 Blackwell Publishing Ltd 2283 – 2288 7 Geochronology; Stratigraphy; Caldera; Campi Flegrei; Deep drilling; Fault model; Geological evolution; Southern Italy; Stratigraphic data; Volcanic areas; Faulting https://www.scopus.com/inward/record.uri?eid=2-s2.0-85050753827&doi=10.1029%2f2017GC007297&partnerID=40&md5=8e3f5fa0be69c984877914b395c3abf6 Cited by: 3; All Open Access, Bronze Open Access Maurizio M. Torrente Alfonsa Milia article Olsen201815 Phase 1 of the Colorado Plateau Coring Project (CPCP-I) recovered a total of over 850m of stratigraphically overlapping core from three coreholes at two sites in the Early to Middle and Late Triassic age largely fluvial Moenkopi and Chinle formations in Petrified Forest National Park (PFNP), northeastern Arizona, USA. Coring took place during November and December of 2013 and the project is now in its post-drilling science phase. The CPCP cores have abundant detrital zircon-producing layers (with survey LA-ICP-MS dates selectively resampled for CA-ID-TIMS U-Pb ages ranging in age from at least 210 to 241 Ma), which together with their magnetic polarity stratigraphy demonstrate that a globally exportable timescale can be produced from these continental sequences and in the process show that a prominent gap in the calibrated Phanerozoic record can be filled. The portion of core CPCP-PFNP13-1A for which the polarity stratigraphy has been completed thus far spans ~ 215 to 209Ma of the Late Triassic age, and strongly validates the longer Newark-Hartford Astrochronostratigraphic-calibrated magnetic Polarity Time-Scale (APTS) based on cores recovered in the 1990s during the Newark Basin Coring Project (NBCP). Core recovery was ~ 100% in all holes (Table 1). The coreholes were inclined ~ 60-75° approximately to the south to ensure azimuthal orientation in the nearly flat-lying bedding, critical to the interpretation of paleomagentic polarity stratigraphy. The two longest of the cores (CPCP-PFNP13-1A and 2B) were CT-scanned in their entirety at the University of Texas High Resolution X-ray CT Facility in Austin, TX, and subsequently along with 2A, all cores were split and processed at the CSDCO/LacCore Facility, in Minneapolis, MN, where they were scanned for physical property logs and imaging. While remaining the property of the Federal Government, the archive half of each core is curated at the NSF-sponsored LacCore Core Repository and the working half is stored at the Rutgers University Core Repository in Piscataway, NJ, where the initial sampling party was held in 2015 with several additional sampling events following. Additional planned study will recover the rest of the polarity stratigraphy of the cores as additional zircon ages, sedimentary structure and paleosol facies analysis, stable isotope geochemistry, and calibrated XRF core scanning are accomplished. Together with strategic outcrop studies in Petrified Forest National Park and environs, these cores will allow the vast amount of surface paleontological and paleoenvironmental information recorded in the continental Triassic of western North America to be confidently placed in a secure context along with important events such as the giant Manicouagan impact at ~ 215:5 Ma (Ramezani et al., 2005) and long wavelength astronomical cycles pacing global environmental change and trends in atmospheric gas composition during the dawn of the dinosaurs. © Author(s) 2018. 2018 English 18168957 10.5194/sd-24-15-2018 Scientific Drilling 24 Copernicus GmbH 15-40 Lamont-Doherty Earth Observatory of Columbia University, Palisades, NY 10964, United States; Department of Geosciences, University of Texas at Dallas, Richardson, TX 75080, United States; Earth and Planetary Sciences, Rutgers University, Piscataway, NJ 08854, United States; Department of Geosciences, University of Arizona, Tucson, AZ 85721, United States; Berkeley Geochronology Center, 2455 Ridge Rd., Berkeley, CA 94709, United States; Natural History Museum of Utah and Department of Geology and Geophysics, University of Utah, Salt Lake City, UT 84108, United States; Petrified Forest National Park, Petrified Forest, AZ 86028, United States; Department of Earth and Atmospheric Sciences, Central Michigan University, Mount Pleasant, MI 48859, United States; Department of Geosciences, University of Oslo, P.O. Box 1047, Blindern, Oslo, 0316, Norway; MARUM Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany; Earth and Environmental Sciences, Rensselaer Polytechnic Institute (RPI), Troy, NY 12180, United States; National Oceanography Centre, Southampton, University of Southampton, Southampton, SO17 1BJ, United Kingdom; Continental Scientific Drilling Coordination Office and LacCore Facility, N.H. Winchell School of Earth Sciences, University of Minnesota, Minneapolis, MN 55455, United States; University of Texas High Resolution X-ray CT Facility, The University of Texas at Austin, Austin, TX 78712, United States; Centro de Geociencias, Universidad Nacional Autónoma de México (UNAM), Boulevard Juriquilla No. 3001, Querétaro, 76230, Mexico; Martin-Luther-Universität, Halle-Wittenberg, Institut für Geowissenschaften, Von-Seckendorff-Platz 3, Halle (Saale), 06120, Germany; State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Paleontology and Center for Excellence in Life and Paleoenvironment, Nanjing, 210008, China Computerized tomography; Exploratory geochemistry; Forestry; Lead alloys; Recovery; Sedimentology; Silicate minerals; Stratigraphy; Thallium alloys; Zircon, Additional sampling; Azimuthal orientation; Environmental change; Federal governments; Global environmental change; Rutgers University; Sedimentary structure; University of Texas, Magnetic polarity https://www.scopus.com/inward/record.uri?eid=2-s2.0-85055482770&doi=10.5194%2fsd-24-15-2018&partnerID=40&md5=ad9459c47e8c131b4e9f4f83ea406f92 cited By 17 P.E. Olsen J.W. Geissman D.V. Kent G.E. Gehrels R. Mundil R.B. Irmis C. Lepre C. Rasmussen D. Giesler W.G. Parker N. Zakharova W.M. Kürschner C. Miller V. Baranyi M.F. Schaller J.H. Whiteside D. Schnurrenberger A. Noren K.B. Shannon R. O'Grady M.W. Colbert J. Maisano D. Edey S.T. Kinney R. Molina-Garza G.H. Bachman J. Sha G. Bachman R. Blakey K. Brady Shannon H. Buhedma M. Colbert G. Gehrels J. Geissman Z. Haque R. Irmis D. Kent S. Kinney W. Kürschner P. Olsen W. Parker M. Schaller J. Whiteside J. MacIntosh article Gao2018327 The first and second members of the Nenjiang Formation (K2n1+2) in the Songliao Basin, northeast China, are an interval of dark-colored mudstone. Paleoenvironmental studies of these strata are useful for understanding the terrestrial environment under a greenhouse climate and hydrocarbon accumulation in lake basins. In this study, clay mineralogy of the K2n1+2 from four borehole or outcrop sections is investigated to understand terrestrial paleoenvironment during the depositional period in the Late Cretaceous. In the mudstone samples, smectite and illite are the predominant clay minerals, and were derived from weathering of parent rocks in a temperate, sub-humid to sub-arid climate; kaolinite and chlorite are minor clay species. The difference in the clay-mineral assemblages between the eastern and western margins of the basin was primarily controlled by provenance lithology, and the high smectite content in the western basin resulted from alteration of volcanic rocks exposed in the Greater Xing’an Range area. The increasing illite content and ratio of illite/smectite percentages in the upper part of the first member of the Nenjiang Formation indicate paleoenvironmental change. This temporal change in the clay-mineral composition was primarily caused by a regionally cooler and drier paleoclimate, consistent with previous paleoenvironmental reconstructions. © 2017, Science China Press and Springer-Verlag GmbH Germany, part of Springer Nature. 2018 English 16747313 10.1007/s11430-017-9110-9 Science China Earth Sciences 61 Science in China Press 327-338 State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing, 100083, China; School of Earth Sciences and Resources, China University of Geosciences, Beijing, 100083, China; State Key Laboratory of Marine Geology, Tongji University, Shanghai, 3200092, China 3 Clay alteration; Kaolinite; Lithology; Minerals; Sedimentary rocks; Volcanic rocks; Weathering, Clay mineral assemblages; Clay mineral compositions; Late cretaceous; Nenjiang Formation; Paleo-environment; Paleoenvironmental change; Paleoenvironmental reconstruction; Songliao basin, Clay minerals, clay mineral; Cretaceous; illite; lithology; mudstone; paleoenvironment; parent body; smectite; weathering, China; Songliao Basin https://www.scopus.com/inward/record.uri?eid=2-s2.0-85032025076&doi=10.1007%2fs11430-017-9110-9&partnerID=40&md5=fb13ef9cd8957a16df25c70a8a959b91 cited By 11 Y. Gao D.P. Xi Z.H. Qin P.F. Ma C.S. Wang article Damcı201829 The Lake Van is the largest Lake in Turkey and the fourth largest soda lake in the World. High resolution (HR) seismic data acquired during 2012 reveals sub-lacustrine terraces, delta clinoforms, channel-networks, active faults and volcanic edifices. The seismic data were correlated with the cores recovered during the 2008 coring and 2010 ICDP PaleoVan drilling campaigns, using synthetic seismograms produced from the MSCL data of the age-modelled cores, thus allowing to date seismic reflector surfaces and to discuss the temporal evolution of the some of the morphological features and structures. Sub-lacustrine channel-network systems are well developed on the shelf areas connect with the river drainage systems on land and extend to water depths of more than 100 m. These drainage systems developed during the major low-stand periods of Lake Van, the last two of which occurred during 15 ka BP and the Younger Dryas with water levels at −200 m and −70 m, respectively. High lake levels similar to today during the early Holocene were followed by lake level oscillations with some low-stands during the Late Holocene. The low stands are characterized by terraces and berms located at 15 m below lake surface (mbls), 25 mbls, 35 mbls and 60 mbls, 70 mbls and 105 mbls. They were most likely related to the rapid climate change (RCC) events such as the 4.2 ka aridity event, Dark Age Cold Period, Medieval Warm Period and Little Ice. The volcanic features are located along the Southern Boundary Fault (SBF). A significant NW-SE trending active fault in the eastern shelf left-laterally offsets a channel by about 500 m and has a small reverse component in the HR seismic profiles. This fault is considered to be the source of Mw = 5.7 Edremit Earthquake of 9 November 2011. NW-SE trending normal faults with a right-lateral strike slip component north of the Northern Basin provides extension in the area. Normal faults are also dominant in the Erciş Strait. Using ages of reflector surfaces we estimate a vertical slip rate of 0.40 mm/yr to ∼0.5 mm/yr on the normal faults in the shelf areas over the last 2–3 ka. © 2017 Elsevier Ltd and INQUA 2018 English 10406182 10.1016/j.quaint.2017.12.047 Quaternary International 486 Elsevier Ltd 29-43 Istanbul Technical University, Eurasia Institute of Earth Sciences, Ayazağa Yerleşkesi, Istanbul, 34469, Turkey; Istanbul Technical University, EMCOL, Department of Geological Engineering, Faculty of Mining, Ayazağa Yerleşkesi, İstanbul, 34469, Turkey active fault; chronology; climate variation; correlation; geomorphology; Holocene; paleoclimate; seismic data; seismic reflection; seismogram; tectonic setting, Lake Van; Turkey https://www.scopus.com/inward/record.uri?eid=2-s2.0-85039904921&doi=10.1016%2fj.quaint.2017.12.047&partnerID=40&md5=c4fc13084b6cc009554927643d025602 cited By 2 E. Damcı M.N. Çağatay article BenDor2018 Floods comprise a dominant hydroclimatic phenomenon in aridlands with significant implications for humans, infrastructure, and landscape evolution worldwide. The study of short-term hydroclimatic variability, such as floods, and its forecasting for episodes of changing climate therefore poses a dominant challenge for the scientific community, and predominantly relies on modeling. Testing the capabilities of climate models to properly describe past and forecast future short-term hydroclimatic phenomena such as floods requires verification against suitable geological archives. However, determining flood frequency during changing climate is rarely achieved, because modern and paleoflood records, especially in arid regions, are often too short or discontinuous. Thus, coeval independent climate reconstructions and paleoflood records are required to further understand the impact of climate change on flood generation. Dead Sea lake levels reflect the mean centennial-millennial hydrological budget in the eastern Mediterranean. In contrast, floods in the large watersheds draining directly into the Dead Sea, are linked to short-term synoptic circulation patterns reflecting hydroclimatic variability. These two very different records are combined in this study to resolve flood frequency during opposing mean climates. Two 700-year-long, seasonally-resolved flood time series constructed from late Pleistocene Dead Sea varved sediments, coeval with significant Dead Sea lake level variations are reported. These series demonstrate that episodes of rising lake levels are characterized by higher frequency of floods, shorter intervals between years of multiple floods, and asignificantly larger number of years that experienced multiple floods. In addition, floods cluster into intervals of intense flooding, characterized by 75% and 20% increased frequency above their respective background frequencies during rising and falling lake-levels, respectively. Mean centennial precipitation in the eastern Mediterranean is therefore coupled with drastic changes in flood frequencies. These drastic changes in flood frequencies are linked to changes in the track, depth, and frequency of mid-latitude eastern Mediterranean cyclones, determining mean climatology resulting in wetter and drier regional climatic episodes. © 2018 The Author(s). 2018 English 20452322 10.1038/s41598-018-25969-6 Scientific Reports 8 Nature Publishing Group Fredy and Nadine Herrmann Institute of Earth Sciences, Hebrew University of Jerusalem, Jerusalem, Israel; Section 5.2: Climate Dynamics and Landscape Evolution, GFZ German Research Centre for Geosciences, Potsdam, Germany 1 article; budget; climate change; flooding; human; hurricane; latitude; precipitation; sediment; time series analysis; Upper Pleistocene; watershed; Dead Sea https://www.scopus.com/inward/record.uri?eid=2-s2.0-85048001902&doi=10.1038%2fs41598-018-25969-6&partnerID=40&md5=2f54d790a2742f3d05bb8fe3cf69f60f cited By 19 Y. Ben Dor M. Armon M. Ahlborn E. Morin Y. Erel A. Brauer M.J. Schwab R. Tjallingii Y. Enzel article Chang20181323 Core samples from the Chicxulub impact structure provide insights into the formation processes of a shallow-marine-target, complex crater. Although previous studies investigated the impactites (generally suevitic and polymict breccias) of the Yaxcopoil-1 (YAX-1) drill core in the Chicxulub impact structure, the interpretation of its deposition remains controversial. Here, we analyze planar deformation features (PDFs), grain size, and abundance of shocked quartz throughout the YAX-1 impactite sequence (794–895 m in depth). PDF orientations of most quartz grains in YAX-1 impactites show a distribution of both low angles ({10 (Formula presented.) 4}, {10 (Formula presented.) 3}, {10 (Formula presented.) 2}) and high angles (orientations higher than 55° to c-axis), while the lower part of the impactite sequence contains quartz showing only PDF orientations of low angles. High-abundance, coarse-grained shocked quartz is found from the lower to middle parts of the impactites, whereas it abruptly changes to low-abundance, fine-grained shocked quartz within the upper part. In the uppermost part of the impactites, repeated oscillations in contents of these two components are observed. PDF orientation pattern suggests most of the shocked quartz grains experienced a range of shock pressure, except two samples in the lower part of impactites, which experienced only a high level of shock. We suggest that the base and lower part of the impactite sequence were formed by ejecta curtain and melt surge deposits, respectively. Our results are also consistent with the interpretation that the middle part of the impactite sequence is fallback ejecta from the impact plume. Additionally, we support the contention that massive seawater resurges into the crater occurred during the deposition of the upper and uppermost part of the impactites. © The Meteoritical Society, 2018. 2018 10.1111/maps.13082 Meteoritics and Planetary Science 53 1323-1340 Department of Earth and Planetary Science, The University of Tokyo, Faculty of Science Bldg. 1, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8654, Japan; International Research Institute of Disaster Science, Tohoku University, 468-1 Aramaki Aza-Aoba, Aoba-ku, Sendai, 980-0845, Japan 7 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85045465497&doi=10.1111%2fmaps.13082&partnerID=40&md5=d10de74b3d85f81ca1bf50daf44f02af cited By 2 Y. Chang K. Goto Y. Sekine E. Tajika conference Elders20181914 Conference paper 2018 Transactions - Geothermal Resources Council 42 1914 – 1927 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85059884523&partnerID=40&md5=37772d677a7436332586a6484f9d84e4 Cited by: 7 Wilfred A. Elders James Shnell Guðmundur Ó. Friðleifsson Albert Albertsson Robert A. Zierenberg article shaoli2018cementing A cement slurry used to deal with difficulties cementing the exploratory well Songke-2 in main land China, has been formulated with a quadripolymer filter loss reducer and a terpolymer phosphonate retarding agent to improve its thermal stability and avoid the risks of “thermal thinning” of the cement slurry. The filter loss and thickening time of the cement slurry were controlled to satisfy the needs of cementing ultra-high temperature wells by adjusting the concentrations of the two additives. Meanwhile, based on particle sizing and the close-packing principle, the particle sizes and concentration of silica sand were optimized, adjusting the ratio of silicon over calcium closing to 1, thereby preventing the decaying of the late-stage strength of set cement at ultra-high temperatures. Furthermore, an elastic tough material developed with particles and fibers was used to enhance the elasticity and toughness of the cement slurry. By optimizing the ratio of these additives, a cement slurry able to tolerate 260 ℃ well temperature was designed. This cement slurry has good stability, density difference between the upper and the lower parts of the cement slurry less than 0.03 g/cm3, thickening time between 200 min and 420 min, filter loss less than 100 mL, 48 h compressive strength greater than 20 MPa, and 7 d compressive strength greater than 38 MPa. The late-stage strength of the set cement is not declining. By optimizing the liner hanging and cementing techniques, and strictly controlling cement slurry density, the integrity of the formations penetrated by the well was maintained, without being fractured during cementing operations. Using high temperature high efficiency flushing spacers, the displacing efficacy was increased, and job safety and cementing job quality were ensured. Well cementing has been performed successfully with high job quality on the Well Songke-2, whose static bottom hole temperature is 260 ℃, and circulating bottom hole temperature 210 ℃. © 2018, The Editorial Board of Drilling Fluid & Completion Fluid. All right reserved. Article 2018 Chinese 10015620 10.3969/j.issn.1001-5620.2018.02.015 钻井液与完井液 35 钻井液与完井液 92-97 2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85055031129&doi=10.3969%2fj.issn.1001-5620.2018.02.015&partnerID=40&md5=7a7aa73bf28c6c6bf76eab06afcff285 Cited by: 3 LI Shaoli SONG Shaoguang article Menzies2018305 Collisional mountain building influences the global carbon cycle through release of CO2 liberated by metamorphic reactions and promoting mechanical erosion that in turn increases chemical weathering and drawdown of atmospheric CO2. The Southern Alps is a carbonate-poor, siliciclastic mountain belt associated with the active Australian Pacific plate boundary. On-going, rapid tectonic uplift, metamorphism and hydrothermal activity are mobilising carbon. Here we use carbon isotope measurements of hot spring fluids and gases, metamorphic host rocks, and carbonate veins to establish a metamorphic carbon budget. We identify three major sources for CO2 within the Southern Alps: (1) the oxidation of graphite; (2) consumption of calcite by metamorphic reactions at the greenschist–amphibolite facies boundary, and (3) the dissolution of groundmass and vein-hosted calcite. There is only a minor component of mantle CO2 arising on the Alpine Fault. Hot springs have molar HCO3 −/Ca2+ ∼9, which is substantially higher than produced by the dissolution of calcite indicating that deeper metamorphic processes must dominate. The total CO2 flux to the near surface environment in the high uplift region of the Southern Alps is estimated to be ∼6.4 × 108 mol/yr. Approximately 87% of this CO2 is sourced from coupled graphite oxidation (25%) and disseminated calcite decarbonation (62%) reactions during prograde metamorphism. Dissolution of calcite and mantle-derived CO2 contribute ∼10% and ∼3% respectively. In carbonate-rich orogens CO2 production is dominated by metamorphic decarbonation of limestones. The CO2 flux to the atmosphere from degassing of hot springs in the Southern Alps is 1.9 to 3.2 × 108 mol/yr, which is 30–50% of the flux to the near surface environment. By contrast, the drawdown of CO2 through surficial chemical weathering ranges between 2.7 and 20 × 109 mol/yr, at least an order of magnitude greater than the CO2 flux to the atmosphere from this orogenic belt. Thus, siliciclastic mountain belts like the Southern Alps are net sinks for atmospheric CO2, in contrast to orogens involving abundant carbonate rocks, such as the Himalaya, that are net CO2 sources. © 2017 The Author(s) 2018 English 0012821X 10.1016/j.epsl.2017.10.010 Earth and Planetary Science Letters 481 Elsevier B.V. 305-315 Ocean and Earth Science, National Oceanography Centre Southampton, University of Southampton, Southampton, SO14 3ZH, United Kingdom; Department of Geology, University of Otago, Dunedin, 9016, New Zealand; Department of Earth and Environmental Science, The University of Michigan, 1100 North University Avenue, Ann Arbor, MI 48109-1005, United States; GNS Science, Private Bag 1930, Dunedin, 9054, New Zealand; Department of Geological Sciences, Stockholm University, Stockholm, SE-10691, Sweden Atmospheric chemistry; Budget control; Calcite; Carbonation; Dissolution; Geochemistry; Graphite; Hot springs; Isotopes; Landforms; Metamorphic rocks; Weathering, Carbon cycles; Carbon isotopes; Chemical weathering; metamorphism; Mountain building, Carbon dioxide, carbon budget; carbon cycle; carbon dioxide; carbon isotope; chemical weathering; host rock; metamorphism; orogeny; siliciclastic deposit; thermal spring; vein (geology), New Zealand; South Island; Southern Alps https://www.scopus.com/inward/record.uri?eid=2-s2.0-85033678533&doi=10.1016%2fj.epsl.2017.10.010&partnerID=40&md5=05101a62d27223beb2345e35f215a789 cited By 9 C.D. Menzies S.L. Wright D. Craw R.H. James J.C. Alt S.C. Cox I.K. Pitcairn D.A.H. Teagle article Glikson2018173 In this chapter we discuss hydrothermal and metasomatic processes that have taken place in impact structures, subsequent to the collapse of the transient cavity and the cooling of the melt sheet and melt rocks. Most of what follows is drawn from Pirajno et al. (Aust J Earth Sci 50:775–796, 2003), Pirajno (Aust J Earth Sci 52:587–620, 2005) and Pirajno and Van Kranendonk (Aust J Earth Sci 52:329–352, 2005), particularly for the Australian examples. The flow of hot aqueous solutions commonly results in the formation of mineral deposits. Therefore, knowledge of post-impact hydrothermal activity is important because it may have resulted in economic mineral deposits. The world-class and widely known Sudbury mineral deposits (Ni, Cu, PGE, Pb, Zn, Au) are perhaps the best and most celebrated expression of mineralization directly related to a meteorite impact (Lightfoot, Nickel sulfide ores and impact melts – origin of the Sudbury Igneous Complex. Elsevier, Amsterdam, 662pp, 2016). Several lines of evidence suggest that the giant gold deposits of the Witwatersrand in South Africa may have been reworked or even enhanced by the effects of the large Vredefort impact structure. These cases will be examined briefly in the sections that follow. Hydrothermal circulation systems associated with impact events have been reported from the Ries (Germany), Puchezh-Katunki (Russia), Jämtland (Sweden), Roter Kamm (Namibia), Manson (USA), the above-mentioned Vredefort, Kärdla (Estonia), Sudbury and Haughton (Canada) structures (Newsom et al., J Geophys Res 91:E239–E251, 1986; Koeberl et al., Geoch Cosmo Acta 53:2113–2118, 1989; Naumov, Meteoritics 28:408–409, 1993; Sturkel et al., Eur J Miner 10: 589–609, 1998; Ames et al., Geology 26: 447–450, 1998; McCarville and Crossey, Geol Soc Am Sp Pap 302:347–379, 1996); Grieve and Thierriault, Annu Rev Earth Planet Sci 28: 305–338, 2000; Osinski et al., Meteor Planet Sci 36:731–745, 2001; Molnár et al., Econ Geol 96:1645–1670, 2001; Puura et al., Impact-induced replacement of plagioclase by K-feldspar in granitoids and amphibolites at the Kärdla crater, Estonia. In: Gilmour I, Koeberl C (eds) Impacts and the early earth. Springer-Verlag, Berlin, pp 417–445, 2000 and Geochemistry of K-enriched impactites, based on drillings into the Kärdla Crater, Estonia. Geol Soc Am Abs with Programs, Denver, Oct. 2002, p 341, 2002). Recently, aspects of hydrothermal alteration in the Chicxulub impact structure have been published in Meteoritic and Space Science (Lüders and Rickers, Meteor Planet Sci 39:1187–1198, 2004; Zürcher and Kring, Meteor Planet Sci 39:1199–1222, 2004; Goto et al., Meteor Planet Sci 39:1233–1247, 2004). © 2018, Springer International Publishing AG. 2018 10.1007/978-3-319-74545-9_7 Modern Approaches in Solid Earth Sciences 14 173-205 Planetary Science Institute, Australian National University, Canberra, ACT, Australia; Centre for Exploration Targeting, The University of Western Australia, Crawley, WA, Australia https://www.scopus.com/inward/record.uri?eid=2-s2.0-85044126254&doi=10.1007%2f978-3-319-74545-9_7&partnerID=40&md5=00dcdc50750e9dbaa378e32946cd11c4 cited By 0 A.Y. Glikson F. Pirajno article Cook20182069 Accurately quantifying the amount of naturally occurring gas hydrate in marine and permafrost environments is important for assessing its resource potential and understanding the role of gas hydrate in the global carbon cycle. Electrical resistivity well logs are often used to calculate gas hydrate saturations, Sh, using Archie's equation. Archie's equation, in turn, relies on an empirical saturation parameter, n. Though n = 1.9 has been measured for ice-bearing sands and is widely used within the hydrate community, it is highly questionable if this n value is appropriate for hydrate-bearing sands. In this work, we calibrate n for hydrate-bearing sands from the Canadian permafrost gas hydrate research well, Mallik 5L-38, by establishing an independent downhole Sh profile based on compressional-wave velocity log data. Using the independently determined Sh profile and colocated electrical resistivity and bulk density logs, Archie's saturation equation is solved for n, and uncertainty is tracked throughout the iterative process. In addition to the Mallik 5L-38 well, we also apply this method to two marine, coarse-grained reservoirs from the northern Gulf of Mexico Gas Hydrate Joint Industry Project: Walker Ridge 313-H and Green Canyon 955-H. All locations yield similar results, each suggesting n ≈ 2.5 ± 0.5. Thus, for the coarse-grained hydrate bearing (Sh &gt; 0.4) of greatest interest as potential energy resources, we suggest that n = 2.5 ± 0.5 should be applied in Archie's equation for either marine or permafrost gas hydrate settings if independent estimates of n are not available. ©2018. American Geophysical Union. All Rights Reserved. 2018 English 21699313 10.1002/2017JB015138 Journal of Geophysical Research: Solid Earth 123 Blackwell Publishing Ltd 2069-2089 School of Earth Science, The Ohio State University, Columbus, OH, United States; U.S. Geological Survey, Woods Hole, MA, United States 3 carbon cycle; electrical resistivity; gas hydrate; hydrocarbon reservoir; marine environment; natural gas; permafrost; saturation; wave velocity, Atlantic Ocean; Gulf of Mexico https://www.scopus.com/inward/record.uri?eid=2-s2.0-85045830707&doi=10.1002%2f2017JB015138&partnerID=40&md5=ce4a46746d7b239ee480f056a990fea9 cited By 76 A.E. Cook W.F. Waite article North2018119 Ancient lake sediments provide opportunities to reconstruct aquatic ecosystems during previous interglacials. In the summer of 2010, the ICDP project PALEOVAN drilled a complete succession of the lacustrine sedimentary sequence deposited during the last ~600,000 years in Lake Van, eastern Anatolia (Turkey). Previous palaeolimnological analysis of the Lake Van sediment record has shown diatoms to be absent over most of the sequence apart from a short interval during the Holocene. Here, we demonstrate the preservation of additional fragmentary diatom records during Marine Isotope Stage (MIS) 7 (243,000–191,000 years ago; Lisiecki and Raymo in Paleoceanography 20:PA1003, 2005; Jouzel et al. in Science 317:793–796, 2007) and MIS5e (130,000–116,000 years ago; Lisiecki and Raymo 2005; Jouzel et al. 2007), each spanning no more than a few thousand years. Although brief, the presence of contrasting diatom assemblages between these two interglacials provide a snapshot of varying water depth and, by inference, climate. Analysis of MIS7e samples suggests that lake water levels were low after a period when the lake was open (i.e., high lake levels with the presence of an outflow present), resulting in higher salinities and possibly less stable bottom waters, which switched between anoxic and oxic states more frequently. By contrast, the diatom assemblages during MIS5e are characteristic of fresh, relatively nutrient rich waters. This suggests that lake levels were high, that the lake was hydrologically open with an outlet, and that the bottom waters were anoxic for long periods of time. Furthermore, our palaeoconductivity estimates and modelling of the past lake volumes with respect to its salt content support the presence of an outflow. © 2017, The Author(s). 2018 English 09212728 10.1007/s10933-017-9973-z Journal of Paleolimnology 59 Springer Netherlands 119-133 Department of Life Sciences, Imperial College London, Silwood Park Campus, London, SL5 7PY, United Kingdom; Geological Institute, Swiss Federal Institute of Technology (ETH), Zurich, Switzerland; Large Lakes Observatory, University of Minnesota, Duluth, MN, United States; Department of Water Resources and Drinking Water, Eawag, Swiss Federal Institute of Aquatic Science and Technology, Überlandstrasse 133, Dübendorf, 8600, Switzerland; Institute of Geological Sciences, University of Bern, Baltzerstrasse 1+3, Bern, 3012, Switzerland; Environmental Change Research Centre, Department of Geography, UCL, London, United Kingdom 1 biostratigraphy; chemical environmental conditions; deposition; depositional environment; diatom; dissolution; fossil record; Holocene; interglacial; lacustrine deposit; lake ecosystem; lake level; marine isotope stage; paleohydrology; paleolimnology; project assessment; salinity; sedimentary sequence; water depth, Anatolia; Lake Van; Turkey, Bacillariophyta https://www.scopus.com/inward/record.uri?eid=2-s2.0-85020688154&doi=10.1007%2fs10933-017-9973-z&partnerID=40&md5=0060ec808c5bdc0584a03b4c0a078507 cited By 10 S.M. North M. Stockhecke Y. Tomonaga A.W. Mackay article Trauth2018321 We used a change point analysis on a late Pleistocene-Holocene lake-sediment record from the Chew Bahir basin in the southern Ethiopian Rift to determine the amplitude and duration of past climate transitions. The most dramatic changes occurred over 240 yr (from 15,700 to 15,460 yr) during the onset of the African Humid Period (AHP), and over 990 yr (from 4875 to 3885 yr) during its protracted termination. The AHP was interrupted by a distinct dry period coinciding with the high-latitude Younger Dryas stadial, which had an abrupt onset (less than 100 yr) at 13,260 yr and lasted until 11,730 yr. Wet-dry-wet transitions prior to the AHP may reflect the high-latitude Dansgaard-Oeschger cycles, as indicated by cross-correlation of the potassium record with the NorthGRIP ice core record between 45-20 ka. These findings may contribute to the debates regarding the amplitude, and duration and mechanisms of past climate transitions, and their possible influence on the development of early modern human cultures. © University of Washington. Published by Cambridge University Press, 2018. 2018 English 00335894 10.1017/qua.2018.30 Quaternary Research (United States) 90 Cambridge University Press 321-330 Institute of Earth and Environmental Science, University of Potsdam, Karl-Liebknecht-Str. 24-25, Potsdam, 14476, Germany; Institute of Geography Education, University of Cologne, Gronewaldstraße 2, Köln, 50931, Germany; Senckenberg Center for Human Evolution and Palaeoenvironment (HEP), Department of Geosciences, University of Tübingen, Hölderlinstrasse 12, Tübingen, 72074, Germany; Addis Ababa University, School of Earth Sciences, P.O. Box 1176, Addis Ababa, Ethiopia; Aberystwyth University, Department of Geography and Earth Sciences, Aberystwyth, SY23 3DB, United Kingdom 2 Hierarchical systems; Principal component analysis, Change-point analysis; Dansgaard-Oeschger cycles; Holocenes; Humid periods; Late Pleistocene; Paleoclimatology; Southern Ethiopian Rift; Younger Dryas, Climate change https://www.scopus.com/inward/record.uri?eid=2-s2.0-85046574708&doi=10.1017%2fqua.2018.30&partnerID=40&md5=1d15c2b8fa47c349f12af7c2e410a7e3 cited By 19 M.H. Trauth V. Foerster A. Junginger A. Asrat H.F. Lamb F. Schaebitz article Zhang20184712 SK-2 East Borehole (SK-2e) is the main borehole of Continental Scientific Drilling Project of Cretaceous Songliao Basin, which is designed to acquire the geophysical log data in the whole borehole, to provide accurate, comprehensive geophysical information for resource exploration and research on paleoclimate and paleoenvironment. Among various well logging methods, natural gamma-ray logging and natural gamma-ray spectral logging can measure natural gamma-ray intensity and uranium (U), thorium (Th), potassium (K) contents, and are effectively applied to radioactive deposit exploration, especially to uranium exploration and research. Conventional logging (including resistivity, acoustic, density and neutron logging) and special logging (including nuclear magnetic resonance, resistivity imaging and elemental capture spectroscopy logging) can obtain lithologic and physical parameters of strata, offering strong support for uranium exploration. In this study, the natural gamma-ray log data was used to identify abnormally high natural radioactivity zones. Based on conventional log data, special log data and previous geological research achievements, the characteristics and genesis of radioactive abnormality were analyzed. The results show that two abnormally high natural radioactivity zones are located in deep-seated Yingcheng Formation. And their depths are 3096.8~3102.8m (Layer I) and 3168.3~3170.9 m (Layer II) respectively. According to the comprehensive analysis of various log data and core data, Layer I is conglomerate, with the maximum gamma of 360 API and high uranium content (20.5~29.3 ppm). Therefore, Layer I has uranium mineralization potential. Analysis shows that tectonic conditions and epigenetic alteration are probably the key factors affecting uranium enrichment which causes abnormally high gamma-ray intensity. It was speculated that fault movements, volcanic activity, and the basin's uplift and erosion provide uranium-bearing groundwater, oil and gas with the migration channel to I layer. The epigenetic reduction of oil and gas eventually leads to uranium enrichment of Layer I. Layer II consists of agglomerate lava and tuff, with the maximum gamma of 250 API, high thorium content (22.4~37.3 ppm) and high uranium content (5.9~11.0 ppm). The rhyolitic components of high thorium content and uranium adsorption by clay minerals may cause the abnormally high gamma-ray intensity in Layer II. The abnormally high radioactivity zones of Yingcheng Formation in SK-2e are characterized by deep burial depths and high uranium contents, indicating uranium prospecting potential in deep zones of Songliao Basin. © 2018, Science Press. All right reserved. 2018 Chinese 00015733 10.6038/cjg2018L0210 Acta Geophysica Sinica 61 Science Press 4712-4728 Key Laboratory of Geo-detection, China University of Geosciences, Beijing, Ministry of Education, Beijing, 100083, China; School of Geophysics and Information Technology, China University of Geosciences, Beijing, 100083, China; Institute of Geophysics and Geomatics, China University of Geosciences, Wuhan, 430074, China; Development and Research Center, China Geological Survey, Beijing, 100037, China 11 Acoustic logging; Acoustic spectroscopy; Boreholes; Boring; Core analysis; Gamma rays; Geophysics; Groundwater; Infill drilling; Neutron logging; Nuclear magnetic logging; Nuclear magnetic resonance spectroscopy; Petroleum prospecting; Radioactivity; Uranium, Continental scientific drillings; Elemental capture spectroscopy; Genesis; Geophysical information; Log response; Natural radioactivity; Songliao basin; Uranium mineralization, Oil well logging, abnormality; adsorption; borehole; Cretaceous; geophysical survey; mineralization; nutrient enrichment; paleoclimate; potassium; radioactivity; radionuclide; thorium; uranium; well logging, China; Songliao Basin https://www.scopus.com/inward/record.uri?eid=2-s2.0-85062673061&doi=10.6038%2fcjg2018L0210&partnerID=40&md5=f505982afc140a87d2b690d978d5b86a cited By 5 S. Zhang C. Zou C. Peng J. Zhao N. Li X. Zhang H. Ma Y. Niu article Terry2018MR317 A unified effective medium model is developed to incorporate the endpoints of perfectly smooth and infinitely rough sphere components and to allow partitioning between rough and smooth grains. We incorporate the unified model into the framework for gas hydrates in unconsolidated sediments using pore-fluid and rock-matrix configurations for grain placement, while reviewing other developments that have taken place in the past four decades. The unified rock-matrix model is validated with data available from the 2002 Mallik gas hydrates project well 5L-38. Gas-hydrate saturation and neutron-porosity logs from this well are used to generate synthetic P- and S-wave velocity models for several values of the friction coefficient. First, we overlaid crossplots of P- versus S-wave velocities for synthetic and measured velocities, and we compared the match until a good choice was found for the friction coefficient. Second, we plotted the synthetic velocities as separate logs of P- and S-wave velocities for each friction coefficient; the synthetic velocity logs were then overlaid on the measured velocities calculated from the sonic logs. Results of a direct comparison of the synthetic and measured velocity logs provide valuable insights into the validation of the unified effective medium model. Recognizing the significance of the Hertz-Mindlin-type effective medium models for gas hydrates in unconsolidated sediments, we incorporate the previous efforts into a single "unified" model and define a common nomenclature. Although we attempt to assign a single friction coefficient value to each hydrate window, it is not surprising that in a real and heterogeneous environment, the value might vary with depth, as it does here at the larger spatial scales. We determine and quantitatively estimate that gas hydrates in sediments are well-predicted with a friction coefficient closer to a smooth sphere model than a rough sphere model. © 2018 Society of Exploration Geophysicists. All rights reserved. 2018 English 00168033 10.1190/geo2017-0513.1 Geophysics 83 Society of Exploration Geophysicists MR317-MR332 University of South Carolina, School of the Earth, Ocean, and Environment, Columbia, SC 29208, United States 6 Algorithms; Elastic moduli; Friction; Gases; Hydration; Models; Neutron logging; Sediments; Shear waves; Spheres; Velocity; Wave propagation, Effective medium model; Friction coefficients; Gas hydrate saturations; Heterogeneous environments; Neutron porosity logs; P- and S-wave velocities; Rock physics; Unconsolidated sediment, Gas hydrates, algorithm; bulk modulus; gas hydrate; numerical model; P-wave; S-wave; sediment analysis; shear modulus; surface roughness; wave velocity https://www.scopus.com/inward/record.uri?eid=2-s2.0-85054152907&doi=10.1190%2fgeo2017-0513.1&partnerID=40&md5=aabfa7db7c0080e4f98806277f8a25f3 cited By 8 D.A. Terry C.C. Knapp article Hadizadeh201814 Previous studies of the San Andreas Fault damage-zone samples from the San Andreas Fault Observatory at Depth (SAFOD) have identified a variety of tectonic microstructures including pressure solution cleavage, calcite-sealed fractures vein fabric, and pyrite and anhydrite hydrothermal fracture sealing. Understanding the deformation provenance of the damage zone rocks and operative deformation mechanism(s) based on preserved microstructures provide insight into overall deformation behavior of the entire seismogenic zone in the creeping section of this transform fault. We analysed the deformation of hydrothermal secondary pyrite in connection with network of calcite veins in a sample of foliated ultracataclasites bordering the actively creeping Southwestern Deforming Zone (SDZ), using SEM, EBSD and CL microscopy. The results show that calcite veins associated with the pressure solution cleavage are crosscut by the secondary pyrite deformed under a range of P-T conditions. Relatively undeformed secondary pyrite is found sealing implosion microbreccia. Our review of previously available data indicates that the damage zone rocks may represent a collage of structural and compositional domains from both locked and creeping sections of the SAF. This interpretation together with results of this study suggest that weak-clay frictional deformation mechanism(s) is likely to be the predominant aseismic creep mechanism at depths below the SAFOD. © 2018 2018 English 01918141 10.1016/j.jsg.2018.09.005 Journal of Structural Geology 117 Elsevier Ltd 14-26 Department of Geography & Geosciences, University of Louisville, Louisville, KY 40292, United States; Department of Earth Ocean & Ecological Sciences, University of Liverpool, Liverpool, United Kingdom Calcite; Microstructure; Pyrites; Strike-slip faults; Structural geology; Transform faults, Aseismic creep in the SAF; Calcite veins; Creep deformation mechanisms; Deformation behavior; Deformation mechanism; Pressure solution; SAFOD; Seismogenic zones, Creep, calcite; cathodoluminescence; creep; deformation mechanism; pressure solution; pyrite; vein (geology) https://www.scopus.com/inward/record.uri?eid=2-s2.0-85053423219&doi=10.1016%2fj.jsg.2018.09.005&partnerID=40&md5=f952112ec8c1631e9c0b15f84a4c9828 cited By 2 J. Hadizadeh A.P. Boyle article Gallant2018895 We present a new probabilistic lava flow hazard assessment for the U.S. Department of Energy's Idaho National Laboratory (INL) nuclear facility that (1) explores the way eruptions are defined and modeled, (2) stochastically samples lava flow parameters from observed values for use in MOLASSES, a lava flow simulator, (3) calculates the likelihood of a new vent opening within the boundaries of INL, (4) determines probabilities of lava flow inundation for INL through Monte Carlo simulation, and (5) couples inundation probabilities with recurrence rates to determine the annual likelihood of lava flow inundation for INL. Results show a 30% probability of partial inundation of the INL given an effusive eruption on the eastern Snake River Plain, with an annual inundation probability of 8.4 × 10-5 to 1.8 × 10-4. An annual probability of 6.2 × 10-5 to 1.2 × 10-4 is estimated for the opening of a new eruptive center within INL boundaries. © 2018 Geological Society of America. 2018 English 00917613 10.1130/G45123.1 Geology 46 Geological Society of America 895-898 School of Geosciences, University of South Florida, 4202 E. Fowler Avenue, Tampa, FL 33620, United States; Planetary Geology, Geophysics and Geochemistry Laboratory, NASA Goddard Space Flight Center, 8800 Greenbelt Road, Greenbelt, MD 20771, United States; Department of Astronomy, University of Maryland, College Park, MD 20742, United States 10 Floods; Intelligent systems; Monte Carlo methods; Probability, Annual probabilities; Effusive eruptions; Hazard Assessment; Idaho national laboratories; Nuclear facilities; Recurrence rates; Snake river plains; U.S. Department of Energy, Hazards https://www.scopus.com/inward/record.uri?eid=2-s2.0-85054126074&doi=10.1130%2fG45123.1&partnerID=40&md5=227aa23c0300c0c73e26ee341c5a7d7d cited By 15 E. Gallant J. Richardson C. Connor P. Wetmore L. Connor article Regattieri201839 Article 2018 10.1016/j.gloplacha.2018.01.003 Global and Planetary Change 162 39 – 52 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85040327384&doi=10.1016%2fj.gloplacha.2018.01.003&partnerID=40&md5=98e221fc3550388fbc6527c0e44b0714 Cited by: 30; All Open Access, Green Open Access Eleonora Regattieri Giovanni Zanchetta Ilaria Isola Petra Bajo Natale Perchiazzi Russell N. Drysdale Chiara Boschi John C. Hellstrom Alexander Francke Bernd Wagner article Lupien2018225 Article 2018 10.1016/j.quascirev.2018.03.012 Quaternary Science Reviews 186 225 – 235 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85043450674&doi=10.1016%2fj.quascirev.2018.03.012&partnerID=40&md5=b4325030617c7c425cc758b8b9becacb Cited by: 46 R.L. Lupien J.M. Russell C. Feibel C. Beck I. Castaneda A. Deino A.S. Cohen article Tong2018215 The Songliao Basin (SLB) located in northeastern China is one of the largest Cretaceous continental sedimentary basins in the world. The SLB is filled with sediments deposited in the Upper Jurassic, the Lower Cretaceous and the Upper Cretaceous epochs. The Nenjiang Formation (K2n) is subdivided into five members, where Member 2 (K2n2) was deposited in the late Santonian in the lower part of the Nenjiang Formation. This member is characterized by a thick succession of organic-rich source rocks. However, the complexity of the depositional environment raises questions about the specific factors that drove this accumulation of organic material. Here, we present data on the total organic carbon (TOC) contents and their stable carbon isotope values (δ13Corg), as well as biomarker data from 50 outcrop samples collected from the Yuewangcheng (YWC) section, in the southeastern SLB. According to the variations of the bulk organic parameters (TOC and δ13Corg) and biomarker indices, the profile could be divided into three stages (stages I–III). The distribution of biomarkers (n-alkanes, steranes and hopanes) and δ13Corg values indicate that the organic matter (OM) in the Lower K2n2 is derived largely from algae and macrophytes, with a minor input from bacteria and land plants. The water column was stratified, as indicated by the presence of gammacerane. Variations in the pristane/phytane (Pr/Ph) and aryl isoprenoids relative to phenanthrene ratio (A-i/P) suggest that bottom waters were anoxic during Stage I (31.5–26.0 m) and Stage II (26.0–16.3 m), with the anoxic layer impinging on the euphotic zone and a relative oxic environment at Stage III (16.3–0 m). This brackish environment persisted in the water over the interval represented by the section, as reflected by methytrimethyltridecyl chromans (MTTCs) Index (MTTCI) and α-MTTC/γ-MTTC ratios. Marine transgressions, with subsequent seawater incursions, can be detected with the presence of 24-n-propyl-cholestanes and 24-isopropyl-cholestanes in the Lower K2n2 sediments, especially during Stage I. These seawater incursions are closely correlated with anoxic conditions and the deposition of organic-rich source rocks. © 2018 Elsevier Ltd 2018 English 01466380 10.1016/j.orggeochem.2018.07.018 Organic Geochemistry 124 Elsevier Ltd 215-227 State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, 510640, China; State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing, 100083, China; University of Chinese Academy of Sciences, Beijing, 100049, China Analytical geochemistry; Biomarkers; Deposition; Paraffins; Seawater; Sediments, Depositional environment; Lacustrine source rocks; Marine transgression; Organic-rich sediment; Organic-rich source rock; Santonian; Stable carbon isotopes; Water columns, Organic carbon, anoxic conditions; biomarker; carbon isotope; Cretaceous; depositional environment; estuarine environment; euphotic zone; Jurassic; macrophyte; organic geochemistry; organic matter; outcrop; phenanthrene; Santonian; seawater; sediment chemistry; sedimentary basin; source rock; total organic carbon; water column, China; Songliao Basin, algae; Embryophyta https://www.scopus.com/inward/record.uri?eid=2-s2.0-85051684042&doi=10.1016%2fj.orggeochem.2018.07.018&partnerID=40&md5=a7412f566036a5a6c4c1ca638543909d cited By 31 X. Tong J. Hu D. Xi M. Zhu J. Song P. Peng article 2018 10.12075/j.issn.1004-4051.2018.S2.019 China Mining Magazine 27 268-271 S2 X. Liu L. Cui H. Guo Z. Wang K. Chen article Greco201859 Article 2018 10.4435/BSPI.2018.04 Bollettino della Societa Paleontologica Italiana 57 59 – 74 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85047527946&doi=10.4435%2fBSPI.2018.04&partnerID=40&md5=b104cd16a9b0b25241f3f1645c6b42b9 Cited by: 13 Francesco Greco Barbara Cavalazzi Axel Hofmann Keyron Hickman-Lewis article Stranghoener2018 The interaction of a single bacterial species (Burkholderia fungorum) with basaltic rocks from the ICDP HSDP2 drill core and synthetic basaltic glasses was investigated in batch laboratory experiments to better understand the role of microbial activity on rock alteration and Fe mobilization. Incubation experiments were performed with drill core basaltic rock samples to investigate differences in the solution chemistry during biotic and abiotic alteration. Additionally, colonization experiments with synthetic basaltic glasses of different Fe redox states and residual stresses were performed to evaluate their influence on microbial activity and surface attachment of cells. In biotic incubation experiments bacterial growth was observed and the release of Fe and other major elements from drill core basaltic rocks to solution exceeded that of abiotic controls only when the rock sample assay was nutrient depleted. The concentration of dissolved major elements in solution in biotic colonization experiments with synthetic basaltic glasses increased with increasing residual stress and Fe(II) content. Furthermore, the concentration of dissolved Fe and Al increased similarly in biotic colonization experiments indicating that their dissolution might be triggered by microbial activity. Surface morphology imaging by SEM revealed that cells on basaltic rocks in incubation experiments were most abundant on the glass and surfaces with high roughness and almost absent on minerals. In colonization experiments, basaltic glasses with residual stress and high Fe(II) content were intensely covered with a cellular biofilm. In contrast, glasses with high Fe(III) content and no residual stress were sparsely colonized. We therefore conclude that structurally bound Fe is most probably used by B. fungorum as a nutrient. Furthermore, we assume that microbial activity overall increased rock dissolution as soon as the environment becomes nutrient depleted. Our results show that besides compositional effects, other factors such as redox state and residual stress can control microbial alteration of basaltic glasses. © 2018 Stranghoener, Schippers, Dultz and Behrens. 2018 English 1664302X 10.3389/fmicb.2018.01252 Frontiers in Microbiology 9 Frontiers Media S.A. Institute of Mineralogy, Leibniz Universität Hannover, Hanover, Germany; Geomicrobiology, Federal Institute for Geosciences and Natural Resources, Hanover, Germany; Institute of Soil Science, Leibniz Universität Hannover, Hanover, Germany JUN glass, abiotic stress; Article; bacterial growth; biotic stress; chemical analysis; glucose intake; Gram negative bacterium; Hawaii; incubation time; microbial activity; microbial colonization; microbial growth; organismal interaction; pH; scanning electron microscopy https://www.scopus.com/inward/record.uri?eid=2-s2.0-85048595587&doi=10.3389%2ffmicb.2018.01252&partnerID=40&md5=b607429350a3cf0aec45533efbb92808 cited By 13 M. Stranghoener A. Schippers S. Dultz H. Behrens article 2018 Acta Geologica Sinica 92 1971-1984 10 Y. Zhu W. Wang H. Zhang J. Yan L. Cao J. Xu Q. Meng X. Tan article Burschil2018593 Article 2018 10.1002/nsg.12011 Near Surface Geophysics 16 593 – 610 6 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85062991714&doi=10.1002%2fnsg.12011&partnerID=40&md5=9f6efc56e3dcb74ba36d92c5783ea640 Cited by: 21; All Open Access, Hybrid Gold Open Access Thomas Burschil Hermann Buness David C. Tanner Ulrike Wielandt-Schuster Dietrich Ellwanger Gerald Gabriel article Zhao2018137 A continuous pollen record from Lake El'gygytgyn (northeastern Russian Arctic) provides detailed information concerning the regional vegetation and climate history during the Mid-Pleistocene Transition (MPT), between 1091 ka (end of Marine Isotope Stage (MIS) 32) and 715 ka (end of MIS 18). Pollen-based qualitative vegetation reconstruction along with biome reconstruction indicate that the interglacial regional vegetation history during the MPT is characterized by a gradual replacement of forest and shrub vegetation by open herbaceous communities (i.e. tundra/cold steppe). The pollen spectra reveal seven vegetation successions that have clearly distinguishable glacial-interglacial cycles. These successions are represented by the intervals of cold deciduous forest (CLDE) biome scores changing from high to low, which are basically in phase with the variations of obliquity from maxima to minima. The dominating influence of obliquity forcing on vegetation successions contradicts with the stronger power of eccentricity, as demonstrated by the result of wavelet analysis based on landscape openness reconstruction. This discrepancy shows that a single index is insufficient for catching signals of all the impacting factors. Comparisons with vegetation and environmental changes in the Asian interior suggest that global cooling during the MPT was probably the key force driving long-term aridification in the Arctic region. The accelerated aridification after MIS 24–22 was probably caused by the additional effect of the Tibetan Plateau uplift, which played an important role on intensification of the Siberian High and westerly jet systems. © 2017 Collegium Boreas. Published by John Wiley & Sons Ltd 2018 English 03009483 10.1111/bor.12262 Boreas 47 Blackwell Publishing Inc. 137-149 Institute of Geology and Mineralogy, University of Cologne, Cologne, 50674, Germany; Institute of Geological Sciences, Palaeonotology Section, Free University of Berlin, Berlin, 12249, Germany; Northeast Interdisciplinary Research Institute, Far East Branch Russian Academy of Sciences, Magadan, 685000, Russian Federation; Earth and Space Sciences, Quaternary Research Center, University of Washington, Seattle, WA 98195, United States; Institute of Geology and Petroleum Technologies, Kazan Federal University, Kazan, 420008, Russian Federation 1 biome; climate variation; forest; herb; paleoclimate; palynology; Pleistocene; shrub; uplift; vegetation, Arctic; China; Chukchi; Elgygytgyn Lake; Qinghai-Xizang Plateau; Russian Federation https://www.scopus.com/inward/record.uri?eid=2-s2.0-85019579600&doi=10.1111%2fbor.12262&partnerID=40&md5=721d59d18886acc78965c03e23c13e2d cited By 13 W. Zhao P.E. Tarasov A.V. Lozhkin P.M. Anderson A.A. Andreev J.A. Korzun M. Melles E.Y. Nedorubova V. Wennrich article Carlino201823 The heat flow and distribution of temperatures at depth in the Campania region were analysed and correlated with the volcanism and tectonics of the area. The temperature data, a part of the inventory of the AGIP, SAFEN and ENEL Companies (Inventario delle Risorse Geotermiche Nazionali), were gathered during drilling campaigns that began in 1940. The Campania region is characterised by the presence of two active and high-risk volcanic districts (the Campi Flegrei, Ischia and Vesuvius) emerging at the western boundary of the Campania Plain structural graben, and by the outcropping of the carbonate basement along the borders of the plain. The thermal anomalies have been correlated to different processes: the rising of the upper mantle (at about 20 km depth), the heat flow mass transport due to advection of hot fluids above magma reservoirs and the pure conductive heat transport of deeper crust. Furthermore, the presence of the carbonate basement has possibly buffered the deeper crustal thermal processes. The data also provided an estimation of the brittle-ductile transition zone that has been compared with the seismicity cut-off depth of the area. © 2018 Elsevier B.V. Article 2018 English 03770273 10.1016/j.jvolgeores.2018.10.015 Journal of Volcanology and Geothermal Research 365 Elsevier B.V. 23 – 37 Campania [Italy]; Italy; Calluna vulgaris; Buildings; Heat transfer; Tectonics; Transport properties; Brittle-ductile transition zone; Campania; Distribution of temperature; Geothermal gradients; Magma reservoirs; Thermal anomalies; Volcanic district; Volcanism; geothermal gradient; heat flow; magma chamber; mass transport; tectonic evolution; temperature gradient; thermal convection; volcanism; Geothermal energy https://www.scopus.com/inward/record.uri?eid=2-s2.0-85055128038&doi=10.1016%2fj.jvolgeores.2018.10.015&partnerID=40&md5=fc13f139eee5912ee3282c87eb2cf2fe Cited by: 15 Stefano Carlino article Byerly2018967 Article 2018 10.1130/G45276.1 Geology 46 967 – 970 11 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85055909624&doi=10.1130%2fG45276.1&partnerID=40&md5=76f46934e57685b28f0fee12e0d96316 Cited by: 29 Benjamin L. Byerly Donald R. Lowe Nadja Drabon Matthew A. Coble Dale H. Burns Gary R. Byerly article Géli2018 Understanding micro-seismicity is a critical question for earthquake hazard assessment. Since the devastating earthquakes of Izmit and Duzce in 1999, the seismicity along the submerged section of North Anatolian Fault within the Sea of Marmara (comprising the "Istanbul seismic gap") has been extensively studied in order to infer its mechanical behaviour (creeping vs locked). So far, the seismicity has been interpreted only in terms of being tectonic-driven, although the Main Marmara Fault (MMF) is known to strike across multiple hydrocarbon gas sources. Here, we show that a large number of the aftershocks that followed the M 5.1 earthquake of July, 25th 2011 in the western Sea of Marmara, occurred within a zone of gas overpressuring in the 1.5-5 km depth range, from where pressurized gas is expected to migrate along the MMF, up to the surface sediment layers. Hence, gas-related processes should also be considered for a complete interpretation of the micro-seismicity (~M &lt; 3) within the Istanbul offshore domain. © 2018 The Author(s). 2018 English 20452322 10.1038/s41598-018-23536-7 Scientific Reports 8 Nature Publishing Group Ifremer, Département Ressources Physiques et Ecosystèmes de Fond de Mer (REM), Plouzané, F-29280, France; CEREGE, Aix Marseille Univ., CNRS, IRD, INRA, Coll. France, Aix-Marseille, France; Lamont-Doherty Earth Observatory, Palisades, NY, United States; Universidad de Los Andes, Bogotà, Colombia; ALomax Scientific, Mouans-Sartoux, 06370, France; Kandilli Observatory and Earthquake Research Institute, Boǧaziçi University, Istanbul, Turkey; Istanbul Technical University, Istanbul, Turkey; Ocean and Earth Science, National Oceanography Centre, Southampton, United Kingdom; School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, United Kingdom; Mineral Research and Exploration General Directorate, MTA, Ankara, Turkey; Institute for Marine Science and Technology, Dokuz Eyiul Universitesi, Izmir, Turkey; Helmholtz-Centre Potsdam German Centre for Geosciences GFZ, Section 4.2 Geomechanics and Rheology, Telegrafenberg, Potsdam, 14473, Germany; Freie Universität Berlin, Department of Earth Sciences, Malteser Strasse 74-100, Berlin, 12249, Germany; Institute of Marine Science, ISMAR-CNR, Bologna, Italy; Istituto Nazionale di Geofisica e Vulcanologia, INGV, Roma, Italy; Faculty of Environmental Science and Engineering, Babes-Bolyai University, Cluj-Napoca, Romania 1 article; earthquake; sediment; Turkey (republic); Marmara Sea https://www.scopus.com/inward/record.uri?eid=2-s2.0-85046363781&doi=10.1038%2fs41598-018-23536-7&partnerID=40&md5=b6cd6460e388083d7538e68a8f64e9b6 cited By 17 L. Géli P. Henry C. Grall J.-B. Tary A. Lomax E. Batsi V. Riboulot E. Cros C. Gürbüz S.E. Işlk A.M.C. Sengor X. Le Pichon L. Ruffine S. Dupré Y. Thomas D. Kalafat G. Bayrakci Q. Coutellier T. Regnier G. Westbrook H. Saritas G. Çifçi M.N. Çağatay M.S. Özeren N. Görür M. Tryon M. Bohnhoff L. Gasperini F. Klingelhoefer C. Scalabrin J.-M. Augustin D. Embriaco G. Marinaro F. Frugoni S. Monna G. Etiope P. Favali A. Bécel article Pilles2018224 Hypervelocity impacts frequently result in the formation of dikes in the crater floor and central uplift. Impact melt-bearing dikes in large terrestrial impact basins – such as the Offset Dikes at the Sudbury impact structure – occur at a large scale, often tens of meters wide and several kilometers in length. The Offset Dikes host significant Ni–Cu–PGE deposits, which include several well-known mines, such as Totten and Copper Cliff that have been mined for nearly 100 years. The Offset Dikes typically consist of a clast- and sulfide-rich core and clast-poor margins. Their formation has been a subject of debate for decades. The most widely proposed model is the early emplacement of clast-poor impact melt shortly after the impact event, followed by the later emplacement of clast- and sulfide-rich impact melt in the center of the dike. An alternative hypothesis is that a single pulse of clast-rich impact melt flowed into the fractured target rocks and flow differentiation resulted in a clast-rich core and a clast-poor margin. In this study, we examine field and petrographic relationships of the Foy Offset Dike to better understand its emplacement. Our results show that the characteristics of the Foy Offset Dike – namely the gradational nature of the contact between the clast-rich and clast-poor phases, the alignment of clasts sub-parallel to this contact, the geochemical similarities and the presence of sulfides within both phases of the dike – are more consistent with the single injection and flow differentiation hypothesis. © 2018 Elsevier B.V. 2018 10.1016/j.epsl.2018.05.023 Earth and Planetary Science Letters 495 224-233 Department of Earth Sciences, Centre for Planetary Science and Exploration, University of Western Ontario, London, Ontario N6A 5B7, Canada; Department of Physics and Astronomy, University of Western Ontario, London, Ontario N6A 5B7, Canada; Wallbridge Mining Company Limited, 129 Fielding Road, Sudbury, ON P3Y 1L7, Canada https://www.scopus.com/inward/record.uri?eid=2-s2.0-85047251885&doi=10.1016%2fj.epsl.2018.05.023&partnerID=40&md5=9746303574732dafc5534de6fcc518b7 cited By 10 E.A. Pilles G.R. Osinski R.A.F. Grieve D. Smith J. Bailey article Janku-Capova20182631 Sixteen temperature logs were acquired during breaks in drilling of the 893m-deep DFDP-2B borehole, which is in the Alpine Fault hanging-wall. The logs record various states of temperature recovery after thermal disturbances induced by mud circulation. The long-wavelength temperature signal in each log was estimated using a sixth-order polynomial, and residual (reduced) temperature logs were analyzed by fitting discrete template wavelets defined by depth, amplitude, and width parameters. Almost two hundred wavelets are correlated between multiple logs. Anomalies generally have amplitudes &lt;1°C, and downhole widths &lt;20m. The largest amplitudes are found in the first day after mud circulation stops, but many anomalies persist with similar amplitude for up to 15 days. Our models show that thermal and hydraulic diffusive processes are dominant during the first few days of re-equilibration after mud circulation stops, and fluid advection of heat in the surrounding rock produces temperature anomalies that may persist for several weeks. Models indicate that the fluid flux normal to the borehole within fractured zones is of order 10−7 to 10−6 m s−1, which is 2–3 orders of magnitude higher than the regional flux. Our approach could be applied more widely to boreholes, as it uses the thermal re-equilibration phase to derive useful information about the surrounding rock mass and its fluid flow regime. ©2018. American Geophysical Union. All Rights Reserved. 2018 English 15252027 10.1029/2017GC007317 Geochemistry, Geophysics, Geosystems 19 Blackwell Publishing Ltd 2631-2646 School of Geography, Environment and Earth Sciences, Victoria University of Wellington, PO Box 600, Wellington, New Zealand; Univ. Grenoble Alpes, Univ. Savoie Mont Blanc, CNRS, IRD, IFSTTAR, ISTerre, Grenoble, 38000, France; GNS Science, Lower Hutt, Wellington, New Zealand; Ocean and Earth Science, National Oceanography Centre Southampton, University of Southampton, European Way, Southampton, SO14 3ZH, United Kingdom; Géosciences Montpellier, Université de Montpellier, CNRS, Montpellier, France 8 Aquifers; Boreholes; Flow of fluids; Fracture; Groundwater; Groundwater resources; Hydrogeology; Mechanical permeability; Rocks, Diffusive process; geothermal; Orders of magnitude; Surrounding rock mass; Temperature anomaly; Temperature recovery; Temperature signal; Thermal disturbance, Thermal logging, aquifer; borehole logging; fluid flow; fractured medium; geothermal system; groundwater; hanging wall; hydrogeology; permeability; rock mechanics; temperature gradient, Alpine Fault Zone; New Zealand; South Island https://www.scopus.com/inward/record.uri?eid=2-s2.0-85052405949&doi=10.1029%2f2017GC007317&partnerID=40&md5=77d021772f41f5d7a9571957b7b66cd4 cited By 6 L. Janku-Capova R. Sutherland J. Townend M.-L. Doan C. Massiot J. Coussens B. Célérier article Carlino2018276 We report combined measurements of petrophysical and geophysical parameters for a 501-m deep borehole located on the eastern side of the active Campi Flegrei caldera (Southern Italy), namely (i) in situ permeability by pumping tests, (ii) laboratory-determined permeability of the drill core, and (iii) thermal gradients by distributed fiber optic and thermocouple sensors. The borehole was drilled during the Campi Flegrei Deep Drilling Project (in the framework of the International Continental Scientific Drilling Program) and gives information on the least explored caldera sector down to pre-caldera deposits. The results allow comparative assessment of permeability obtained from both borehole (at depth between 422 a 501 m) and laboratory tests (on a core sampled at the same depth) for permeability values of ~10−13 m2 (borehole test) and ~10−15 m2 (laboratory test) confirm the scale-dependency of permeability at this site. Additional geochemical and petrophysical determinations (porosity, density, chemistry, mineralogy and texture), together with gas flow measurements, corroborate the hypothesis that discrepancies in the permeability values are likely related to in-situ fracturing. The continuous distributed temperature profile points to a thermal gradient of about 200 °C km−1. Our findings (i) indicate that scale-dependency of permeability has to be carefully considered in modelling of the hydrothermal system at Campi Flegrei, and (ii) improve the understanding of caldera dynamics for monitoring and mitigation of this very high volcanic risk area. © 2018 Elsevier B.V. Article 2018 English 03770273 10.1016/j.jvolgeores.2018.05.003 Journal of Volcanology and Geothermal Research 357 Elsevier B.V. 276 – 286 Istituto Nazionale di Geofisica e Vulcanologia, sezione di Napoli “Osservatorio Vesuviano”, Via Diocleziano 328, Naples, 80124, Italy; Department of Earth and Environmental Sciences, Ludwig-Maximilians-Universität, Munich Theresienstrasse 41/III, Munich, 80333, Germany; School of Environment, University of Auckland, 23 Symonds Street, Auckland, 1142, New Zealand Campania [Italy]; Campi Flegrei; Italy; Napoli [Campania]; Boreholes; Core drilling; Drilling; Fiber optic sensors; Flow of gases; Mechanical permeability; Minerals; Risk assessment; Temperature; Thermal gradients; Thermocouples; Volcanoes; Campi Flegrei; Combined measurements; Comparative assessment; Continental scientific drillings; Geophysical parameters; Petrophysics; Temperature profiles; Thermocouple sensors; borehole; caldera; crustal structure; deep drilling; hydrothermal system; permeability; temperature profile; volcano; Boring https://www.scopus.com/inward/record.uri?eid=2-s2.0-85047065989&doi=10.1016%2fj.jvolgeores.2018.05.003&partnerID=40&md5=aae041483ae8954f6d7dbc0615659660 Cited by: 12 Stefano Carlino Monica Piochi Anna Tramelli Angela Mormone Cristian Montanaro Bettina Scheu Mayer Klaus article Proust20181564 Understanding the history, causes, and impact of sea-level changes is a challenge for our societies that face accelerated global sea-level rise. In this context, improvement of our knowledge of sea-level changes and shoreline migration at geological time scales is critical. The preserved, laterally correlative sedimentary record of continental erosion on passive margins has been used to reconstruct past sea level. However, the detailed nature of a basic clinothem progradational pattern observed on many of these margins is still poorly known. This paper describes the sedimentary facies and interprets the depositional environments and the architecture of the clinothems of the New Jersey shelf (offshore northeastern USA) to depict the origin and controls of the distribution of the sediment on the margin. We analyze 612 cores totaling 1311 m in length collected at three sites 60 km offshore Atlantic City, New Jersey, during International Ocean Discovery Program-International Continental Scientific Drilling Program (IODP-ICDP) Expedition 313. The three sites sampled the lower to middle Miocene passive margin sediments of the New Jersey shelf clinothems. We also collected wireline logs at the three sites and tied the sedimentary architecture to the geometry observed on seismic profiles. The observed sediment distribution in the clinoform complex differs from that of current models based on seismic data, which predict a progressive increase in mud and decrease in sand contents in a seaward direction. In contrast, we observe that the clinoforms are largely composed of muds, with sands and coarser material concentrated at the rollover, the bottomset, and the toe of the slope. The shelf clinothem topsets are storm-influenced mud whereas the foreset slope is composed of a mud wedge largely dominated by density current deposits (e.g., low-density turbidites and debrites). The architecture of the clinothem complex includes a composite stack of ~30-m-thick clinothem units each made up of four systems tracts (Transgressive, Highstand, Forced- Regressive, and Lowstand Systems Tract) building individual transgressiveregressive sequences. The presence of mud-rich facies deposited during highstands on the topset of the clinoform, 40-60 km offshore from the sand-prone shoreface deposit (observed in the New Jersey onshore delta plain), and the lack of subaerial erosion (and continental depositional environments) point to a depositional model involving a subaerial delta (onshore) feeding a distant subaqueous delta. During forced regressions, shelf-edge deltas periodically overstep the stacks of flood-influenced, offshore-marine mud wedges of the New Jersey subaqueous delta, bringing sand to the rollover and building up the large-scale shelf-prism clinothems. The clinothem complex develops on a gently dipping platform with a ramp-like morphology (apparent dip of 0.75°-0.5°) below mean storm wave base, in 30-50 m of water depth, 40-60 km seaward of the coastal area. Its shape depends on the balance between accommodation and sedimentation rates. Subaqueous deltas show higher accumulation rates than their subaerial counterparts and prograde three times further and faster than their contemporaneous shoreline. The increase in the intensity of waves (height and recurrence intervals) favors the separation between subaqueous and subaerial deltas, and as a consequence, the formation of a flat topset geometry, a decrease in flood events and fluvial discharge, an overall progressive decrease in sediment grain size (from sequence m5.45, ca. 17.8-17.7 Ma, onwards), as well as an increase in sedimentation rates on the foresets of the clinoforms. All of these are recognized as preliminary signals that might characterize the entry into the Neogene icehouse world. © 2018 The Authors. 2018 English 1553040X 10.1130/GES01545.1 Geosphere 14 Geological Society of America 1564-1591 Geosciences, CNRS, University of Rennes, Rennes, 35042, France; Department of Earth Science, College of Science, Ibaraki University, Bunkyo Mito, 310-8512, Japan; Camborne School of Mines, University of Exeter, Penryn Campus, Penryn, Cornwall, TR10 9FE, United Kingdom; School of Earth and Environment, University of Leeds, Leeds, LS2 9JT, United Kingdom; Géosciences, CNRS, University of Montpellier, Montpellier, 34090, France; Géosciences Océan, CNRS, Institut Universitaire Européen de La Mer, Plouzané, 29280, France; New Jersey Geological Survey, Trenton, NJ 08638, United States 4 Deposits; Erosion; Floods; Sand; Sea level; Sedimentology; Seismic waves; Seismology; Storms; Tectonics, Continental scientific drillings; Depositional environment; Depositional models; Facies architecture; Global sea level rise; Recurrence intervals; Sediment distribution; Sedimentary architecture, Sediments, continental margin; depositional environment; facies analysis; Miocene; passive margin; progradation; reconstruction; sea level change; spatial distribution, Atlantic Ocean; New Jersey Shelf https://www.scopus.com/inward/record.uri?eid=2-s2.0-85051137615&doi=10.1130%2fGES01545.1&partnerID=40&md5=e363d248d76d5ded08d4967aa327a334 cited By 8 J.-N. Proust H. Pouderoux H. Ando S.P. Hesselbo D.M. Hodgson J. Lofi M. Rabineau P.J. Sugarman article jackson2018extreme 2018 Am. Ceram. Soc. Bull 97 22--28 5 Marie D Jackson John P Oleson Juhyuk Moon Yi Zhang Heng Chen Magnus T Gudmundsson article Christeson20181 Joint International Ocean Discovery Program and International Continental Scientific Drilling Program Expedition 364 drilled into the peak ring of the Chicxulub impact crater. We present P-wave velocity, density, and porosity measurements from Hole M0077A that reveal unusual physical properties of the peak-ring rocks. Across the boundary between post-impact sedimentary rock and suevite (impact melt-bearing breccia) we measure a sharp decrease in velocity and density, and an increase in porosity. Velocity, density, and porosity values for the suevite are 2900–3700 m/s, 2.06–2.37 g/cm3, and 20–35%, respectively. The thin (25 m) impact melt rock unit below the suevite has velocity measurements of 3650–4350 m/s, density measurements of 2.26–2.37 g/cm3, and porosity measurements of 19–22%. We associate the low velocity, low density, and high porosity of suevite and impact melt rock with rapid emplacement, hydrothermal alteration products, and observations of pore space, vugs, and vesicles. The uplifted granitic peak ring materials have values of 4000–4200 m/s, 2.39–2.44 g/cm3, and 8–13% for velocity, density, and porosity, respectively; these values differ significantly from typical unaltered granite which has higher velocity and density, and lower porosity. The majority of Hole M0077A peak-ring velocity, density, and porosity measurements indicate considerable rock damage, and are consistent with numerical model predictions for peak-ring formation where the lithologies present within the peak ring represent some of the most shocked and damaged rocks in an impact basin. We integrate our results with previous seismic datasets to map the suevite near the borehole. We map suevite below the Paleogene sedimentary rock in the annular trough, on the peak ring, and in the central basin, implying that, post impact, suevite covered the entire floor of the impact basin. Suevite thickness is 100–165 m on the top of the peak ring but 200 m in the central basin, suggesting that suevite flowed downslope from the collapsing central uplift during and after peak-ring formation, accumulating preferentially within the central basin. © 2018 Elsevier B.V. 2018 10.1016/j.epsl.2018.05.013 Earth and Planetary Science Letters 495 1-11 University of Texas Institute for Geophysics, Jackson School of Geosciences, Austin, United States; Department of Geological Sciences, Jackson School of Geosciences, Austin, United States; Department of Earth Science and Engineering, Imperial College, London, United Kingdom; Alfred Wegener Institute Helmholtz Centre of Polar and Marine Research, Bremerhaven, Germany; Lunar and Planetary Institute, Houston, United States; Department of Geology, University of Leicester, United Kingdom; Géosciences Montpellier, Université de Montpellier, France; Department of Physics, University of Alberta, Canada; Department of Geology, University of Freiburg, Germany; SM 312, Mza 7, Chipre 5, Resid. Isla Azul, Cancun, Quintana Roo, Mexico; Institut für Geologie, Universität Hamburg, Germany; Eyring Materials Center, Arizona State University, Tempe, United States; Department of Geosciences, Pennsylvania State University, University Park, United States; Biogéosciences Laboratory, Université de Bourgogne-Franche Comté, France; Analytical, Environmental and Geo-Chemistry, Vrije Universiteit Brussel, Brussels, Belgium; School of Physics and Astronomy, University of Edinburgh, United Kingdom; Department of Chemistry, WA-Organic and Isotope Geochemistry Centre (WA-OIGC), Curtin University, Bentley, Australia; Natural History Museum, Vienna, Austria; British Geological Survey, Edinburgh, United Kingdom; International Research Institute of Disaster Science, Tohoku University, Sendai, Japan; United Kingdom Hydrographic Office, Taunton, United Kingdom; Groupe de Physico-Chimie de l'Atmosphère, L'Institut de Chimie et Procédés pour l'Énergie, l'Environnement et la Santé (ICPEES), Université de Strasbourg, France; Instituto de Geofísica, Universidad Nacional Autónoma De México, Ciudad de México, Mexico; School of Geographical and Earth Sciences, University of Glasgow, United Kingdom; Argon Isotope Facility, Scottish Universities Environmental Research Centre (SUERC), East Kilbride, United Kingdom; Department of Geology and Geophysics, University of Utah, Salt Lake City, United States; Japan Agency for Marine–Earth Science and Technology, Kanagawa, Japan; Faculty of Earth and Life Sciences (FALW), Vrije Universiteit, Amsterdam, Netherlands; Earth and Planetary Sceinces, Rutgers University, New Brunswick, United States; Kochi Institute for Core Sample Research, Japan Agency for Marine–Earth Science and Technology, Kochi, Japan; Department of Geosciences, University of Alaska, Fairbanks, United States; School of Earth Sciences, Planetary Science Institute, China University of Geosciences (Wuhan), China; Department of Chemistry, Toho University, Chiba, Japan; NASA Astrobiology Institute, United States; Department of Earth, Atmospheric, and Planetary Sciences, Purdue University, United States; University of Texas Institute for Geophysics, Jackson School of Geosciences, Austin, United States; Ocean Resources Research Center for Next Generation, Chiba Institute of Technology, Chiba, Japan https://www.scopus.com/inward/record.uri?eid=2-s2.0-85047062192&doi=10.1016%2fj.epsl.2018.05.013&partnerID=40&md5=5f49ee7757f4f43bed4cd388b01f3f95 cited By 46 G.L. Christeson S.P.S. Gulick J.V. Morgan C. Gebhardt D.A. Kring E. Le Ber J. Lofi C. Nixon M. Poelchau A.S.P. Rae M. Rebolledo-Vieyra U. Riller A. Wittmann T.J. Bralower E. Chenot P. Claeys C.S. Cockell M.J.L. Coolen L. Ferrière S. Green K. Goto H. Jones C.M. Lowery C. Mellett R. Ocampo-Torres L. Pérez-Cruz A.E. Pickersgill C. Rasmussen H. Sato J. Smit S.M. Tikoo N. Tomioka J. Urrutia-Fucugauchi M.T. Whalen L. Xiao K.E. Yamaguchi article Dutta2018 Scientific deep drilling at Koyna, western India provides a unique opportunity to explore microbial life within deep biosphere hosted by ~65 Myr old Deccan basalt and Archaean granitic basement. Characteristic low organic carbon content, mafic/felsic nature but distinct trend in sulfate and nitrate concentrations demarcates the basaltic and granitic zones as distinct ecological habitats. Quantitative PCR indicates a depth independent distribution of microorganisms predominated by bacteria. Abundance of dsrB and mcrA genes are relatively higher (at least one order of magnitude) in basalt compared to granite. Bacterial communities are dominated by Alpha-, Beta-, Gammaproteobacteria, Actinobacteria and Firmicutes, whereas Euryarchaeota is the major archaeal group. Strong correlation among the abundance of autotrophic and heterotrophic taxa is noted. Bacteria known for nitrite, sulfur and hydrogen oxidation represent the autotrophs. Fermentative, nitrate/sulfate reducing and methane metabolising microorganisms represent the heterotrophs. Lack of shared operational taxonomic units and distinct clustering of major taxa indicate possible community isolation. Shotgun metagenomics corroborate that chemolithoautotrophic assimilation of carbon coupled with fermentation and anaerobic respiration drive this deep biosphere. This first report on the geomicrobiology of the subsurface of Deccan traps provides an unprecedented opportunity to understand microbial composition and function in the terrestrial, igneous rock-hosted, deep biosphere. © 2018, The Author(s). 2018 English 20452322 10.1038/s41598-018-35940-0 Scientific Reports 8 Nature Publishing Group Environmental microbiology and genomics laboratory, Department of Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur, 721302, India; School of Bioscience, Indian Institute of Technology Kharagpur, Kharagpur, 721302, India; School of Environmental Science and Engineering, Indian Institute of Technology Kharagpur, Kharagpur, 721302, India; Ministry of Earth Sciences, Borehole Geophysics Research Laboratory, Karad, 415114, India; CSIR-National Geophysical Research Institute, Hyderabad, 500007, India; Department of Geology and Geophysics, Indian Institute of Technology Kharagpur, Kharagpur, 721302, India 1 RNA 16S, biodiversity; biology; environmental microbiology; genetics; India; metagenome; metagenomics; microbiology; microflora; procedures; sediment, Biodiversity; Computational Biology; Environmental Microbiology; Geologic Sediments; India; Metagenome; Metagenomics; Microbiota; RNA, Ribosomal, 16S https://www.scopus.com/inward/record.uri?eid=2-s2.0-85057525609&doi=10.1038%2fs41598-018-35940-0&partnerID=40&md5=11fd0f12a199be11e4cd9a6f76e22800 cited By 33 A. Dutta S. Dutta Gupta A. Gupta J. Sarkar S. Roy A. Mukherjee P. Sar article Xu2018396 The late Early Jurassic Toarcian Stage represents the warmest interval of the Jurassic Period, with an abrupt rise in global temperatures of up to ∼7 °C in mid-latitudes at the onset of the early Toarcian Oceanic Anoxic Event (T-OAE; ∼183 Ma). The T-OAE, which has been extensively studied in marine and continental successions from both hemispheres, was marked by the widespread expansion of anoxic and euxinic waters, geographically extensive deposition of organic-rich black shales, and climatic and environmental perturbations. Climatic and environmental processes following the T-OAE are, however, poorly known, largely due to a lack of study of stratigraphically well-constrained and complete sedimentary archives. Here, we present integrated geochemical and physical proxy data (high-resolution carbon-isotope data (δ13C), bulk and molecular organic geochemistry, inorganic petrology, mineral characterisation, and major- and trace-element concentrations) from the biostratigraphically complete and expanded entire Toarcian succession in the Llanbedr (Mochras Farm) Borehole, Cardigan Bay Basin, Wales, UK. With these data, we (1) construct the first high-resolution biostratigraphically calibrated chemostratigraphic reference record for nearly the complete Toarcian Stage, (2) establish palaeoceanographic and depositional conditions in the Cardigan Bay Basin, (3) show that the T-OAE in the hemipelagic Cardigan Bay Basin was marked by the occurrence of gravity-flow deposits that were likely linked to globally enhanced sediment fluxes to continental margins and deeper marine (shelf) basins, and (4) explore how early Toarcian (tenuicostatum and serpentinum zones) siderite formation in the Cardigan Bay Basin may have been linked to low global oceanic sulphate concentrations and elevated supply of iron (Fe) from the hinterland, in response to climatically induced changes in hydrological cycling, global weathering rates and large-scale sulphide and evaporite deposition. © 2017 The Authors Article 2018 English 0012821X 10.1016/j.epsl.2017.12.037 Earth and Planetary Science Letters 484 Elsevier B.V. 396 – 411 Cardigan Bay; United Kingdom; Wales; Carbon; Deposits; Geochemistry; Iron deposits; Iron ores; Isotopes; Sedimentology; Sulfur compounds; Trace elements; Weathering; Carbon isotope stratigraphy; Early Jurassic; Global weathering rates; Gravity flows; Oceanic anoxic events; siderite; biostratigraphy; carbon cycle; carbon isotope; deposition; depositional environment; evaporite; global climate; paleoceanography; paleotemperature; siderite; stratigraphy; sulfide; Toarcian; weathering; Stratigraphy https://www.scopus.com/inward/record.uri?eid=2-s2.0-85044768889&doi=10.1016%2fj.epsl.2017.12.037&partnerID=40&md5=651d1f0f30fe35bed87527811ccdde64 Cited by: 101; All Open Access, Green Open Access, Hybrid Gold Open Access Weimu Xu Micha Ruhl Hugh C. Jenkyns Jennifer M. Huggett Daniel Minisini Clemens V. Ullmann James B. Riding Johan W.H. Weijers Marisa S. Storm Lawrence M.E. Percival Erdem F. Idiz Erik W. Tegelaar Stephen P. Hesselbo article li2018design 2018 Exploration Engineering (Rock & Soil Drilling and Tunneling) 45 56-60 2 C Li LN Shen article Avice201882 We have analyzed ancient atmospheric gases trapped in fluid inclusions contained in minerals of Archean (3.3 Ga) to Paleozoic (404 Ma) rocks in an attempt to document the evolution of the elemental composition and isotopic signature of the atmosphere with time. Doing so, we aimed at understanding how physical and chemical processes acted over geological time to shape the modern atmosphere. Modern atmospheric xenon is enriched in heavy isotopes by 30–40‰ u−1 relative to Solar or Chondritic xenon. Previous studies demonstrated that, 3.3 Ga ago, atmospheric xenon was isotopically fractionated (enriched in the light isotopes) relative to the modern atmosphere, by 12.9 ± 1.2 (1σ) ‰ u−1, whereas krypton was isotopically identical to modern atmospheric Kr. Details about the specific and progressive isotopic fractionation of Xe during the Archean, originally proposed by Pujol et al. (2011), are now well established by this work. Xe isotope fractionation has evolved from 21‰ u−1 at 3.5 Ga to 12.9‰ u−1 at 3.3 Ga. The current dataset provides some evidence for stabilization of the Xe fractionation between 3.3 and 2.7 Ga. However, further studies will be needed to confirm this observation. After 2.7 Ga, the composition kept evolving and reach the modern-like atmospheric Xe composition at around 2.1 Ga ago. Xenon may be the second atmospheric element, after sulfur, to show a secular isotope evolution during the Archean that ended shortly after the Archean-Proterozoic transition. Fractionation of xenon indicates that xenon escaped from Earth, probably as an ion, and that Xe escape stopped when the atmosphere became oxygen-rich. We speculate that the Xe escape was enabled by a vigorous hydrogen escape on the early anoxic Earth. Organic hazes, scavenging isotopically heavy Xe, could also have played a role in the evolution of atmospheric Xe. For 3.3 Ga-old samples, Ar-N2 correlations are consistent with a partial pressure of nitrogen (pN2) in the Archean atmosphere similar to, or lower than, the modern one, thus requiring other processes than a high pN2 to keep the Earth's surface warm despite a fainter Sun. The nitrogen isotope composition of the atmosphere at 3.3 Ga was already modern-like, attesting to inefficient nitrogen escape to space since that time. © 2018 The Authors Article 2018 English 00167037 10.1016/j.gca.2018.04.018 Geochimica et Cosmochimica Acta 232 Elsevier Ltd 82 – 100 Archean; atmospheric chemistry; fluid inclusion; isotopic composition; isotopic fractionation; nitrogen isotope; paleoatmosphere; Proterozoic; xenon https://www.scopus.com/inward/record.uri?eid=2-s2.0-85046634100&doi=10.1016%2fj.gca.2018.04.018&partnerID=40&md5=c9c15af7a45ae34a563becb53ff0585c Cited by: 69; All Open Access, Green Open Access, Hybrid Gold Open Access G. Avice B. Marty R. Burgess A. Hofmann P. Philippot K. Zahnle D. Zakharov article Potter2018 Basalts erupted in the Snake River Plain of central Idaho and sampled in the Kimama drill core link eruptive processes to the construction of mafic intrusions over 5.5Ma. Cyclic variations in basalt composition reveal temporal chemical heterogeneity related to fractional crystallization and the assimilation of previously-intruded mafic sills. A range of compositional types are identified within 1,912m of continuous drill core: Snake River olivine tholeiite (SROT), low K SROT, high Fe-Ti, and evolved and high K-Fe lavas similar to those erupted at Craters of the Moon National Monument. Detailed lithologic and geophysical logs document 432 flow units comprising 183 distinct lava flows and 78 flowgroups. Each lava flowrepresents a single eruptive episode, while flow groups document chemically and temporally related flows that formed over extended periods of time. Temporal chemical variation demonstrates the importance of source heterogeneity and magma processing in basalt petrogenesis. Low-K SROT and high Fe-Ti basalts are genetically related to SROT as, respectively, hydrothermally-altered and fractionated daughters. Cyclic variations in the chemical composition of Kimama flow groups are apparent as 21 upward fractionation cycles, six recharge cycles, eight recharge-fractionation cycles, and five fractionation-recharge cycles. We propose that most Kimama basalt flows represent typical fractionation and recharge patterns, consistent with the repeated influx of primitive SROT parental magmas and extensive fractional crystallization coupled with varying degrees of assimilation of gabbroic to ferrodioritic sills at shallow to intermediate depths over short durations. Trace element models show that parental SROT basalts were generated by 5–10% partial melting of enriched mantle at shallow depths above the garnet-spinel lherzolite transition. The distinctive evolved and high K-Fe lavas are rare. Found at four depths, 319, 1045, 1,078, and 1,189m, evolved and high K-Fe flows are compositionally unrelated to SROT magmas and represent highly fractionated basalt, probably accompanied by crustal assimilation. These evolved lavas may be sourced from the Craters of the Moon/Great Rift system to the northeast. The Kimama drill core is the longest record of geochemical variation in the central Snake River Plain and reinforces the concept of magma processing in a layered complex. © 2018 Potter, Shervais, Christiansen and Vetter. 2018 English 22966463 10.3389/feart.2018.00010 Frontiers in Earth Science 6 Frontiers Media S.A. Department of Geology, Utah State University, Logan, UT, United States; Department of Geological Sciences, Brigham Young University, Provo, UT, United States; Department of Geology, Centenary College of Louisiana, Shreveport, LA, United States Basalt; Binary alloys; Drills; Infill drilling; Iron alloys; Moon; Olivine; Petrology; Rivers; Titanium alloys; Trace elements, Chemical compositions; Chemical heterogeneities; Drill core; Fractional crystallization; Geochemical variations; Mid-crustal sill complex; Snake river plains; Tholeiite, Core drilling, basalt; crystal structure; data assimilation; fractional crystallization; hydrothermal alteration; magma; petrogenesis; petrology; tholeiitic basalt, Idaho; Snake River Plain; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-85043571691&doi=10.3389%2ffeart.2018.00010&partnerID=40&md5=210aa79559b5fc4730547b0a04474401 cited By 14 K.E. Potter J.W. Shervais E.H. Christiansen S.K. Vetter article Zanchetta2018154 In the DEEP core from the Lake Ohrid ICDP drilling project, the carbon isotope composition of bulk organic matter (δ13CTOC) over the last 516 ka shows a negative correlation with total organic carbon (TOC) and total inorganic carbon (TIC). This relationship is marked by periods of lower δ13CTOC values corresponding to higher TIC and TOC. Along with TOC/TN, the correlation between δ13CTOC and δ13CTIC suggests that most of the organic matter in the core is from aquatic primary production within the lake. The combination of TOC, TIC, and δ13CTOC is able to disentangle long-term glacial/interglacial cycles and, to a lesser extent, millennial scale climate variability. Over the longer term, δ13CTOC shows modest variability, indicating that the δ13C of the dissolved inorganic carbon (DIC) pool is stabilised by the supply of karst spring water characterised by δ13CDIC influenced by the bedrock δ13C value, and the long residence time of the lake water and well mixed upper water column promoting equilibration with atmospheric CO2. However, comparison between arboreal pollen (AP%), TIC and TOC data indicates that the δ13CTOC signal is modulated by the leaching of soil CO2 through runoff and spring discharge, changes in primary productivity, and recycling of organic matter within the lake, all affecting δ13CDIC. Exceptionally low δ13CTOC during some interglacial periods (e.g. MIS7 and MIS9) possibly indicate rapid intensification of organic matter recycling and/or increasing stratification and enhanced methanogenesis, even if the latter process is not supported by the sedimentological data. © 2018 Elsevier Ltd Article 2018 English 02773791 10.1016/j.quascirev.2018.10.022 Quaternary Science Reviews 202 Elsevier Ltd 154 – 165 Dipartimento di Scienze della Terra, University of Pisa, Pisa, 56126, Italy; Istituo Nazionale di Geofisica e Vulcanologia, Roma, Italy; Istituto di Geoscienze e Georisorse-CNR (IGG-CNR), Pisa, 56100, Italy; School of Earth and Environmental Sciences, University of Wollongong, Wollongong, NSW 2522, Australia; Institute of Geology and Mineralogy, University of Cologne, Köln, Germany; NERC Isotope Geosciences Facilities, British Geological Survey, Keyworth, Nottingham, NG7 2RD, United Kingdom; Centre for Environmental Geochemistry, School of Biosciences, Sutton Bonington Campus, University of Nottingham, Loughborough, LE12 5RD, United Kingdom; Institute of Geological Sciences & Oeschger Centre for Climate Change Research, University of Bern, Bern, 3012, Switzerland; Università di Roma La Sapienza, Dipartimento di Biologia Ambientale, piazzale A. Moro 5, Roma, Italy Balkans; Lake Ohrid; Biogeochemistry; Biological materials; Carbon dioxide; Groundwater; Isotopes; Lakes; Paleolimnology; Recycling; Springs (components); Springs (water); Carbon isotope composition; Dissolved inorganic carbon; Europe; Lake Ohrid; Organic matter recycling; Pleistocene; Stable isotopes; Total inorganic carbon; carbon cycle; carbon isotope; freshwater environment; glacial-interglacial cycle; isotopic composition; karst; lacustrine environment; lake water; methanogenesis; paleolimnology; Pleistocene; primary production; spring water; stratification; Organic carbon https://www.scopus.com/inward/record.uri?eid=2-s2.0-85055115207&doi=10.1016%2fj.quascirev.2018.10.022&partnerID=40&md5=111dd5ab3ec5b8a2f9ebca22e2e1f69a Cited by: 13; All Open Access, Green Open Access Giovanni Zanchetta Ilaria Baneschi Alexander Francke Chiara Boschi Eleonora Regattieri Bernd Wagner Jack H. Lacey Melanie J. Leng Hendrik Vogel Laura Sadori article Jones201841 Expansive Late Cretaceous lacustrine deposits of East Asia offer unique stratigraphic records to better understand regional responses to global climate events, such as oceanic anoxic events (OAEs), and terrestrial organic carbon burial dynamics. This study presents bulk organic carbon isotopes (δ13Corg), elemental concentrations (XRF), and initial osmium ratios (187Os/188Os, Osi) from the Turonian–Coniacian Qingshankou Formation, a ∼5 Ma lacustrine mudstone succession in the Songliao Basin of northeast China. A notable δ13Corg excursion (∼+2.5‰) in organic carbon-lean Qingshankou Members 2–3 correlates to OAE3 in the Western Interior Basin (WIB) of North America within temporal uncertainty of high-precision age models. Decreases in carbon isotopic fractionation (Δ13C) through OAE3 in the WIB and Songliao Basin, suggest that significantly elevated global rates of organic carbon burial drew down pCO2, likely cooling climate. Despite this, Osi chemostratigraphy demonstrates no major changes in global volcanism or weathering trends through OAE3. Identification of OAE3 in a lake system is consistent with lacustrine records of other OAEs (e.g., Toarcian OAE), and underscores that terrestrial environments were sensitive to climate perturbations associated with OAEs. Additionally, the relatively radiogenic Osi chemostratigraphy and XRF data confirm that the Qingshankou Formation was deposited in a non-marine setting. Organic carbon-rich intervals preserve no compelling Osi evidence for marine incursions, an existing hypothesis for generating Member 1's prolific petroleum source rocks. Based on our results, we present a model for water column stratification and source rock deposition independent of marine incursions, detailing dominant biogeochemical cycles and lacustrine organic carbon burial mechanisms. © 2017 Elsevier B.V. 2018 English 0012821X 10.1016/j.epsl.2017.11.046 Earth and Planetary Science Letters 484 Elsevier B.V. 41-52 Department of Earth and Planetary Sciences, Northwestern University, Evanston, IL 60208, United States; Department of Earth System Science, Stanford University, Stanford, CA 94305, United States; State Key Laboratory of Biogeology and Environmental Geology, School of Earth Sciences and Resources, China University of Geosciences, Beijing, China; Department of Earth Sciences, Durham University, Durham, DH1 3LE, United Kingdom; Department of Geological Sciences, Stanford University, Stanford, CA 94305, United States Biogeochemistry; Isotopes; Lakes; Petroleum geology; Stratigraphy; Weathering, Biogeochemical cycling; Chemostratigraphy; Oceanic Anoxic Event; Osmium isotopes; Paleoclimates; Songliao basin, Organic carbon, anoxic conditions; biogeochemical cycle; carbon isotope; chemostratigraphy; Cretaceous; lacustrine deposit; mudstone; organic carbon; osmium isotope; paleoclimate; paleoenvironment, China; Songliao Basin; Western Interior https://www.scopus.com/inward/record.uri?eid=2-s2.0-85040671880&doi=10.1016%2fj.epsl.2017.11.046&partnerID=40&md5=5282b0c5935b54c98b805ec361592c57 cited By 36 M.M. Jones D.E. Ibarra Y. Gao B.B. Sageman D. Selby C.P. Chamberlain S.A. Graham article Viehberg2018139 Archaeological findings, numerical human dispersal models and genome analyses suggest several time windows in the past 200 kyr (thousands of years ago) when anatomically modern humans (AMH) dispersed out of Africa into the Levant and/or Arabia. From close to the key hominin site of Omo-Kibish, we provide near continuous proxy evidence for environmental changes in lake sediment cores from the Chew Bahir basin, south Ethiopia. The data show highly variable hydroclimate conditions from 116 to 66 kyr BP with rapid shifts from very wet to extreme aridity. The wet phases coincide with the timing of the North African Humid Periods during MIS5, as defined by Nile discharge records from the eastern Mediterranean. The subsequent record at Chew Bahir suggests stable regional hydrological setting between 58 and 32 kyr (MIS4 and 3), which facilitated the development of more habitable ecosystems, albeit in generally dry climatic conditions. This shift, from more to less variable hydroclimate, may help account for the timing of later dispersal events of AMH out of Africa. © 2018 The Authors Article 2018 English 02773791 10.1016/j.quascirev.2018.09.008 Quaternary Science Reviews 202 Elsevier Ltd 139 – 153 Institute for Geology and Mineralogy, University of Cologne, Zülpicher Straße 49A, Cologne, 50674, Germany; NERC Isotope Geosciences Facilities, British Geological Survey, Nottingham, NG12 5GG, United Kingdom; School of Environmental Sciences, University of HullHU6 7RX, United Kingdom; Centre for Environmental Geochemistry, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Leicestershire, LE12 5RD, United Kingdom; Steinmann Institute for Geology, Mineralogy, and Palaeontology, University of Bonn, Nussallee 8, Bonn, 53115, Germany; Institute of Geography, University of Cologne, Albertus-Magnus-Platz, Cologne, 50923, Germany; Max Planck Institute for Meteorology, Bundesstr. 53, Hamburg, 20146, Germany; Institute of Geophysics and Meteorology, University of Cologne, Pohligstraße 3, Cologne, 50969, Germany; Institute for Meteorology and Climate Research, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, Eggenstein-Leopoldshafen, 76344, Germany; School of Earth Sciences, Addis Ababa University, P.O. Box 1176, Addis Ababa, Ethiopia; Department of Geography and Earth Sciences, Aberystwyth University, Aberystwyth, SY23 3DB, United Kingdom; Minerals and Waste Directorate, British Geological Survey, Nottingham, NG12 5GG, United Kingdom; Institute of Geography Education, University of Cologne, Gronewaldstraße 2, Cologne, 50931, Germany Geology, Archaeological findings; Climatic conditions; Eastern Mediterranean; Environmental change; Genome analysis; Humid periods; Lake sediment cores; Rapid shifts, Natural sciences, anatomy; archaeology; aridity; climate conditions; dispersal; environmental change; horn; lacustrine deposit; marine isotope stage; sediment core, Arabian Sea; Ethiopia; Indian Ocean; Levantine Sea; Mediterranean Sea; Mediterranean Sea (East), Homo sapiens https://www.scopus.com/inward/record.uri?eid=2-s2.0-85054097526&doi=10.1016%2fj.quascirev.2018.09.008&partnerID=40&md5=d9639709eb7d34107181b80f7c3e203c Cited by: 30; All Open Access, Green Open Access, Hybrid Gold Open Access Finn A. Viehberg Janna Just Jonathan R. Dean Bernd Wagner Sven Oliver Franz Nicole Klasen Thomas Kleinen Patrick Ludwig Asfawossen Asrat Henry F. Lamb Melanie J. Leng Janet Rethemeyer Antoni E. Milodowski Martin Claussen Frank Schäbitz article Duverger2018196 We analyse the complete earthquake archive of the western Corinth Rift using both crosscorrelations between pairs of event waveforms and accurate differential traveltimes observed at common stations, in order to identify small-scale fault structures at depth. The waveform database was generated by the dense Corinth Rift Laboratory network and includes about 205 000 events between 2000 and 2015. Half of them are accurately relocated using doubledifference techniques. The novelty of this relocated catalogue is the integration of the recent westernmost earthquakes due to the extension of the network in 2010 to the western extremity of the Corinth Rift and the consideration of the whole database over more than 15 yr. The total relocated seismicity exhibits well-defined clusters at the root of the main normal faults mainly between 5 and 10 km depth in the middle of the gulf and illuminates thin active structure planes dipping north about 20° under the northern coast. Some seismicity is observed in the footwall of the main active faults, along theWest and East Helike faults.We also built a multiplet database based on waveform similarity taking into account cross-correlation coefficients weighted by signal-to-noise ratios. Short-termmultiplets are concentrated in the middle of the gulf along the Kamarai fault system, in a 1-2 km thick layer at 6-8 km depth, interpreted as a highly fractured geological layer. They are often associated to slow seismic migration velocities occurring in this zone during strong swarm episodes and are thus likely to be triggered by pore pressure variations. On the other hand, most long-term and regular multiplets are located deeper (7- 10 km), under the northern coast, within a layer less than 0.3 km thick. They occur at the border of nearly planar structures with low seismicity rate, which we identify as fault planes, and they may be explained by aseismic slip on the fault surface around them. This supports the existence of an immature structure growing downdip towards the north at the base of the active geological layer, which possibly connects to the ductile middle crust around 15 km depth, as suggested by the occurrence of deeper events in the continuity of the 1995-fault plane. The different migration velocities (from 0.05 km d-1 to several km d-1) highlighted during the western 2014-swarms indicate that both pore pressure and creep diffusion are operating in the fault zone. The fast migrations observed in the Psathopyrgos fault zone, where a slow slip event was detected by dilatometers in 2002, compare with that for creeping faults. To the west, from spatial distribution of events, we show that the Rion-Patras fault connecting the western extremity of the Corinth Rift fault system to the Patras Rift, is dipping around 60° north-west with a rake angle of -115°. Finally, we identified two new areas within the central active zone which may correspond to large scale, locked asperities on active fault surfaces, similar in size to the main asperity broken during the 1995, MW 6.3, Aigion earthquake. © The Author(s) 2018. Article 2018 English 0956540X 10.1093/gji/ggy264 Geophysical Journal International 215 Oxford University Press 196 – 221 1 Corinth Rift; Greece; Ionian Sea; Mediterranean Sea; Database systems; Earthquakes; Pore pressure; Signal to noise ratio; Cross-correlation coefficient; Double-difference technique; Earthquake dynamics; Europe; Pressure variations; Seismicity and tectonics; Transient deformation; Waveform similarity; deformation; earthquake mechanism; normal fault; rift zone; seismic migration; seismicity; signal-to-noise ratio; tectonics; wave velocity; waveform analysis; Fault slips https://www.scopus.com/inward/record.uri?eid=2-s2.0-85056608760&doi=10.1093%2fgji%2fggy264&partnerID=40&md5=b620fbbb8069d1e40729140e1cb93422 Cited by: 30; All Open Access, Green Open Access C. Duverger S. Lambotte P. Bernard H. Lyon-Caen A. Deschamps A. Nercessian article Lofi20181 Expedition 364 was a joint IODP and ICDP mission-specific platform (MSP) expedition to explore the Chicxulub impact crater buried below the surface of the Yucatán continental shelf seafloor. In April and May 2016, this expedition drilled a single borehole at Site M0077 into the crater's peak ring. Excellent quality cores were recovered from ~ 505 to ~1335m below seafloor (m b.s.f.), and high-resolution open hole logs were acquired between the surface and total drill depth. Downhole logs are used to image the borehole wall, measure the physical properties of rocks that surround the borehole, and assess borehole quality during drilling and coring operations. When making geological interpretations of downhole logs, it is essential to be able to distinguish between features that are geological and those that are operation-related. During Expedition 364 some drilling-induced and logging-related features were observed and include the following: effects caused by the presence of casing and metal debris in the hole, logging-tool eccentering, drilling-induced corkscrew shape of the hole, possible re-magnetization of low-coercivity grains within sedimentary rocks, markings on the borehole wall, and drilling-induced changes in the borehole diameter and trajectory. © Author(s) 2018. 2018 10.5194/sd-24-1-2018 Scientific Drilling 24 1-13 Géosciences Montpellier, University of Montpellier, CNRS, University of Antilles, Montpellier, France; British Geological Survey, Edinburgh, United Kingdom; DOSECC Exploration Services, Salt Lake City, UT, United States; Department of Geology, University of Leicester, United Kingdom; Department of Earth and Planetary Sciences, Rutgers UniversityNJ, United States; Centre Européen de Recherche et d'Enseignement des Géosciences de l'Environnement, Aix-en-Provence, France; Department of Physics, University of Alberta, Canada; Department of Earth, Atmospheric and Planetary Sciences, Purdue UniversityIN, United States; Institute for Geophysics and Department of Geological Sciences, Jackson School of Geosciences, University of Texas at Austin, Austin, TX, United States; Department of Earth Science and Engineering, Imperial College London, London, United Kingdom; Biogéosciences Laboratory, Université de Bourgogne-Franche Comté, Dijon, France; Analytical, Environmental and Geo-Chemistry, Vrije Universiteit Brussel, Brussels, Belgium; Centre for Astrobiology, School of Physics and Astronomy, University of Edinburgh, Edinburgh, United Kingdom; Department of Chemistry, WA-Organic and Isotope Geochemistry Centre, Curtin University, Perth, WA, Australia; Natural History Museum, Vienna, Austria; Alfred Wegener Institute Helmholtz Centre of Polar and Marine Research, Bremerhaven, Germany; International Research Institute of Disaster Science, Tohoku University, Sendai, Japan; Department of Geosciences, Pennsylvania State University, University Park, PA, United States; Lunar and Planetary Institute, Houston, TX, United States; ICPEES, Université de Strasbourg, Strasbourg, France; Instituto de Geofísica, Universidad Nacional Autónoma De México, Mexico City, Mexico; School of Geographical and Earth Sciences, University of Glasgow, Glasgow, United Kingdom; Department of Geology, University of Freiburg, Freiberg, Germany; Independent consultant, Cancun, Mexico; Institut für Geologie, Universität Hamburg, Hamburg, Germany; Japan Agency for Marine-Earth Science and Technology, Kanagawa, Japan; Faculty of Earth and Life Sciences FALW, Vrije Universiteit Amsterdam, Amsterdam, Netherlands; Kochi Institute for Core Sample Research, Japan Agency for Marine-Earth Science and Technology, Kochi, Japan; Department of Geosciences, University of Alaska Fairbanks, Fairbanks, AK, United States; LeRoy Eyring Center for Solid State Science, Arizona State University, Tempe, AZ, United States; School of Earth Sciences, Planetary Science Institute, China University of Geosciences, Wuhan, China; Department of Chemistry, Toho University, Chiba, Japan https://www.scopus.com/inward/record.uri?eid=2-s2.0-85055514599&doi=10.5194%2fsd-24-1-2018&partnerID=40&md5=be1f05cf2d1a0fbe00532464fb4900ee cited By 4 J. Lofi D. Smith C. Delahunty E. Le Ber L. Brun G. Henry J. Paris S. Tikoo W. Zylberman P.A. Pezard B. Célérier C. Nixon S.P.S. Gulick J.V. Morgan E. Chenot G.L. Christeson P. Claeys C.S. Cockell M.J.L. Coolen L. Ferrière C. Gebhardt K. Goto S. Green H. Jones D.A. Kring C.M. Lowery C. Mellett R. Ocampo-Torres L. Pérez-Cruz A.E. Pickersgill M. Poelchau A.S.P. Rae C. Rasmussen M. Rebolledo-Vieyra U. Riller H. Sato J. Smit N. Tomioka J. Urrutia-Fucugauchi M.T. Whalen A. Wittmann L. Xiao K.E. Yamaguchi T.J. Bralower article Lensky2018150 Article 2018 10.1002/2017WR021536 Water Resources Research 54 150 – 160 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85040597750&doi=10.1002%2f2017WR021536&partnerID=40&md5=d81ae538e54ebf06d8e89f711e855603 Cited by: 33; All Open Access, Bronze Open Access N.G. Lensky I.M. Lensky A. Peretz I. Gertman J. Tanny S. Assouline article Makaroğlu201844 Detailed magnetic analysis of the four sediment cores from Lake Van, Eastern Turkey dating back to 9.4 cal ka BP were carried out for discriminating and correlating tephras and laminated sediments in four different cores. Six tephra units (T0, T1, T2, T3, T4 and T5) with distinct magnetic properties were identified in the cores. The tephra units are characterized by ferrimagnetic material, with a grain size in the pseudo single domain (PSD) range. There is no significant correlation between magnetic susceptibility peaks of the different tephra units except for the tephra T1 and T2. On the contrary ARM profiles show significant correlations as remanent magnetization indicators. The tephra units T1 and T2, have a higher magnetic susceptibility and a higher intensity of remanent magnetization, and finer grain size than the other tephra units. The results suggest that there is a clear difference between the magnetic properties of the different tephra units and the lake sediments. Our findings show that also differential deposition of volcanic material including magnetic mineral occurs during the transport with distance from the volcanic source. © 2018 Elsevier Ltd and INQUA 2018 English 10406182 10.1016/j.quaint.2018.03.012 Quaternary International 486 Elsevier Ltd 44-56 Istanbul University, Faculty of Engineering, Department of Geophysical Engineering, Avcilar, Istanbul 34320, Turkey; Istanbul Technical University, Eastern Mediterranean Centre for Oceanography and Limnology EMCOL and Faculty of Mines, Department of Geological Engineering, Maslak, Istanbul 34469, Turkey; Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences, Section 5.2 – Paleoclimate and Landscape Evolution, Potsdam, 14473, Germany; University of Helsinki, Department of Physics, Division of Geophysics and Astronomy, Helsinki, FIN-00014, Finland geochemistry; Holocene; lacustrine deposit; magnetic mineral; magnetic susceptibility; remanent magnetization; sediment core; tephra, Lake Van; Turkey https://www.scopus.com/inward/record.uri?eid=2-s2.0-85044507473&doi=10.1016%2fj.quaint.2018.03.012&partnerID=40&md5=71af34ee8b14c83898756ba2fae473b7 cited By 5 Ö. Makaroğlu M.N. Çağatay N.R. Nowaczyk L.J. Pesonen N. Orbay article Mohammadmoradi2018786 The identification of methane hydrate behavior in porous media is one of the most challenging yet rewarding pore-level visualization and simulation tasks. The hydrate morphology influences the physical characteristics of the host sediments as during the hydrate formation and dissociation processes the pore space and flow pathways constantly evolve. Here, a direct three-phase pore morphological simulation approach is proposed, verified and utilized to simulate hydrate deformities and predict fluid occupancies and absolute and effective permeabilities of hydrate-bearing geological formations. The proposed technique simulates capillary-dominant displacements by applying a set of geomaterial rules directly to the pixels of pore-level porous media images. The case studies are sandy microstructures generated based on the particle size distributions of the Mallik gas hydrate deposit. The fluid occupancy profiles, absolute permeability, and hydraulic tortuosity curves are comparable with the experimental datasets. The sensitivity analysis shows that although the gas relative permeability is less sensitive to the hydrate specifications, the porosity, grain size distribution, and hydrate content and occupancy remarkably influence the rock absolute permeability. © 2017 Elsevier Ltd 2018 English 02648172 10.1016/j.marpetgeo.2017.11.016 Marine and Petroleum Geology 89 Elsevier Ltd 786-798 University of Calgary, Canada Dissociation; Gas permeability; Grain size and shape; Hydration; Methane; Particle size; Porous materials; Sensitivity analysis; Size distribution, Absolute permeability; Effective permeability; Gas relative permeabilities; Geometrical simulations; Grain size distribution; Morphological simulation; Physical characteristics; Visualization and simulation, Gas hydrates, displacement; hydrocarbon reservoir; methane; microstructure; permeability; pore space; porous medium; sensitivity analysis https://www.scopus.com/inward/record.uri?eid=2-s2.0-85033802254&doi=10.1016%2fj.marpetgeo.2017.11.016&partnerID=40&md5=60119c252c34c2bd2ac90435e8731ebd cited By 20 P. Mohammadmoradi A. Kantzas article 2018 10.1029/2018EO104123 Eos 99 L. Joel article Lüdecke201813330 New geochemical data from the Malawi Rift (Chiwondo Beds, Karonga Basin) fill a major spatial gap in our knowledge of hominin adaptations on a continental scale. Oxygen (δ 18 O), carbon (δ 13 C), and clumped (Δ 47 ) isotope data on paleosols, hominins, and selected fauna elucidate an unexpected diversity in the Pleistocene hominin diet in the various habitats of the East African Rift System (EARS). Food sources of early Homo and Paranthropus thriving in relatively cool and wet wooded savanna ecosystems along the western shore of paleolake Malawi contained a large fraction of C 3 plant material. Complementary water consumption reconstructions suggest that ca. 2.4 Ma, early Homo (Homo rudolfensis) and Paranthropus (Paranthropus boisei) remained rather stationary near freshwater sources along the lake margins. Time-equivalent Paranthropus aethiopicus from the Eastern Rift further north in the EARS consumed a higher fraction of C 4 resources, an adaptation that grew more pronounced with increasing openness of the savanna setting after 2 Ma, while Homo maintained a high versatility. However, southern African Paranthropus robustus had, similar to the Malawi Rift individuals, C 3 -dominated feeding strategies throughout the Early Pleistocene. Collectively, the stable isotope and faunal data presented here document that early Homo and Paranthropus were dietary opportunists and able to cope with a wide range of paleohabitats, which clearly demonstrates their high behavioral flexibility in the African Early Pleistocene. © 2018 National Academy of Sciences. All Rights Reserved. Article 2018 English 00278424 10.1073/pnas.1809439115 Proceedings of the National Academy of Sciences of the United States of America 115 National Academy of Sciences 13330 – 13335 52 Adaptation, Physiological; Animals; Biological Evolution; Carbon Isotopes; Dental Enamel; Diet; Ecosystem; Environment; Feeding Behavior; Fossils; History, Ancient; Hominidae; carbon; adaptation; Article; C3 plant; diet; ecosystem; enamel; evolution; feeding behavior; fluid intake; fossil hominin; habitat; Homo rudolfensis; isotope analysis; Malawi; nonhuman; Paranthropus boisei; Pleistocene; priority journal; animal; chemistry; diet; environment; fossil; history; hominid; metabolism; physiology https://www.scopus.com/inward/record.uri?eid=2-s2.0-85059214057&doi=10.1073%2fpnas.1809439115&partnerID=40&md5=2107c0532544fc2ba036af9756f7c2f3 Cited by: 21; All Open Access, Green Open Access, Hybrid Gold Open Access Tina Lüdecke Ottmar Kullmer Ulrike Wacker Oliver Sandrock Jens Fiebig Friedemann Schrenk Andreas Mulch article Stelbrink20181969 Due to the ubiquity and high dispersal capacity of unicellular eukaryotes, their often extraordinary diversity found in isolated and long-lived ecosystems such as ancient lakes is typically attributed to multiple colonization events rather than to in situ speciation. However, respective evolutionary studies are very scarce and the often high number of species flocks in ancient lakes across multicellular taxa raises the question whether unicellular species, such as diatoms, may radiate as well. Here, we use an integrative approach that includes molecular data from benthic diatom species of the genus Aneumastus endemic to ancient Lake Ohrid, fossil data obtained from the sediment record of a recent deep-drilling project and biogeographical information to test if this group, indeed, constitutes a species flock. Molecular-clock and phylogenetic analyses indicate a young monophyletic group of several endemic species. Molecular, fossil and biogeographical data strongly suggest a rapid intralacustrine diversification, which was possibly triggered by the emergence of novel habitats. This finding is the first evidence for a species flock in diatoms and suggests that in situ speciation is also a relevant evolutionary process for unicellular eukaryotes in isolated ecosystems. © 2018 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2018 European Society For Evolutionary Biology Article 2018 English 1010061X 10.1111/jeb.13368 Journal of Evolutionary Biology 31 Blackwell Publishing Ltd 1969 – 1975 12 Diatoms; Evolution, Molecular; Fossils; Fresh Water; Genetic Variation; Phylogeny; Time Factors; Lake Ohrid; Aneumastus; Bacillariophyta; Protista; fresh water; biogeography; colonization; diatom; endemic species; eukaryote; evolutionary biology; fossil record; freshwater environment; habitat type; molecular analysis; phylogenetics; sediment analysis; species flock; diatom; fossil; genetic variation; genetics; molecular evolution; phylogeny; physiology; time factor https://www.scopus.com/inward/record.uri?eid=2-s2.0-85052797074&doi=10.1111%2fjeb.13368&partnerID=40&md5=515268d12f4e361ebe3d67605326d89a Cited by: 15; All Open Access, Bronze Open Access Björn Stelbrink Elena Jovanovska Zlatko Levkov Nadja Ognjanova-Rumenova Thomas Wilke Christian Albrecht article Kirana20189 Past changes in the Earth's magnetic field can be highlighted through reconstructions of magnetic paleointensity. Many magnetic field variation features are global, and can be used for the detailed correlation and dating of sedimentary records. On the other hand, sedimentary magnetic records also exhibit features on a regional, rather than a global scale. Therefore, the development of regional scale magnetic field reconstructions is necessary to optimize magnetic paleointensity dating. In this paper, a 60 thousand year (kyr) paleointensity record is presented, using the core TOW10-9B of Lake Towuti, located in the island of Sulawesi, Indonesia, as a part of the ongoing research towards understanding the Indonesian environmental history, and reconstructing a high-resolution regional magnetic record from dating the sediments. Located in the East Sulawesi Ophiolite Belt, the bedrock surrounding Lake Towuti consists of ultramafic rocks that render the lake sediments magnetically strong, creating challenges in the reconstruction of the paleointensity record. These sediment samples were subject to a series of magnetic measurements, followed by testing the obtained paleointensity records resulting from normalizing natural remanent magnetization (NRM) against different normalizing parameters. These paleointensity records were then compared to other regional, as well as global, records of magnetic paleointensity. The results show that for the magnetically strong Lake Towuti sediments, an anhysteretic remanent magnetization (ARM) is the best normalizer. A series of magnetic paleointensity excursions are observed during the last 60 kyr, including the Laschamp excursion at 40 kyr BP, that provide new information about the magnetic history and stratigraphy of the western tropical Pacific region. We conclude that the paleointensity record of Lake Towuti is reliable and in accordance with the high-quality regional and global trends. © 2017 Elsevier B.V. Article 2018 English 00319201 10.1016/j.pepi.2017.12.007 Physics of the Earth and Planetary Interiors 275 Elsevier B.V. 9 – 18 Greater Sunda Islands; Lake Towuti; Malili Lakes; South Sulawesi; Sulawesi; Sulawesi; Sunda Isles; Geomagnetism; Lakes; Lithology; Magnetic fields; Magnetization; Repair; Sedimentology; Sediments; Stratigraphy; Anhysteretic remanent magnetizations; Earth's magnetic field; Environmental history; Laschamp excursions; Magnetic field variations; Natural remanent magnetization; Normalizing parameters; Relative paleointensity; geological record; geomagnetic field; lacustrine deposit; magnetic intensity; ophiolite; paleoenvironment; paleointensity; paleomagnetism; reconstruction; stratigraphic correlation; Magnetism https://www.scopus.com/inward/record.uri?eid=2-s2.0-85040597017&doi=10.1016%2fj.pepi.2017.12.007&partnerID=40&md5=6f6281912666780ac5eb7aef8b091d27 Cited by: 3 Kartika Hajar Kirana Satria Bijaksana John King Gerald Hendrik Tamuntuan James Russell La Ode Ngkoimani Darharta Dahrin Silvia Jannatul Fajar article 10.1785/0220170095 The Deep Fault Drilling Project (DFDP) is a multinational scientific drilling effort to study the evolution, structure, and seismogenesis of the Alpine fault, New Zealand, via in situ measurements of fault rock properties. The second phase of drilling (DFDP‐2), undertaken in the Whataroa Valley in late 2014, was intended to intersect the Alpine fault at a depth of around 1 km. In conjunction with the drilling and on‐site science activities, a real‐time seismic monitoring scheme and traffic‐light response protocol were established to detect, locate, and if necessary respond to seismicity within 30 km of the drill site. This network was operated around the clock between late August 2014 and early January 2015, and we detected and located 493 earthquakes of ML 0.6–4.2. None of these earthquakes occurred within 3 km of the drill site, and nor did any of the seismicity detected require changes to drilling operations. The monitoring was undertaken using open‐source software operated by an international team of 16 seismologists (including eight postgraduate students) working in 7 institutions and 3 countries to provide rapid on‐ and off‐site manual checking and relocating of events. The team’s standard response time between detection and final location was less than 30 min under normal background seismicity conditions and up to 1 hr during swarm activity and for low‐priority, distant (≥30  km epicentrally from the drill site) earthquakes. This article documents the methodology, infrastructure, protocols, outcomes, and key lessons of this monitoring. 2017 09 0895-0695 10.1785/0220170095 Seismological Research Letters 88 1443-1454 6 https://doi.org/10.1785/0220170095 Calum J. Chamberlain Carolin M. Boese Jennifer D. Eccles Martha K. Savage Laura‐May Baratin John Townend Anton K. Gulley Katrina M. Jacobs Adrian Benson Sam Taylor‐Offord Clifford Thurber Bin Guo Tomomi Okada Ryota Takagi Keisuke Yoshida Rupert Sutherland Virginia G. Toy inbook stein_goldstein_2017 2017 10.1017/9781316106754.012 Quaternary of the Levant: Environments, Climate Change, and Humans Cambridge University Press Enzel, Yehouda and Bar-Yosef, OferEditors 107–114 Mordechai Stein Steven L. Goldstein article Allen20176160 The Alpine Fault, a transpressional plate boundary between the Australian and Pacific plates, is known to rupture quasiperiodically with large magnitude earthquakes (Mw ~8). The hydraulic and elastic properties of fault zones are thought to vary over the seismic cycle, influencing the nature and style of earthquake rupture and associated processes. We present a suite of laboratory permeability and P (Vp) and S (Vs) wave velocity measurements performed on fault lithologies recovered during the first phase of the Deep Fault Drilling Project (DFDP-1), which sampled principal slip zone (PSZ) gouges, cataclasites, and fractured ultramylonites, with all recovered lithologies overprinted by abundant secondary mineralization, recording enhanced fluid-rock interaction. Core material was tested in three orthogonal directions, orientated relative to the down-core axis and, when present, foliation. Measurements were conducted with pore pressure (H2O) held at 5 MPa over an effective pressure (Peff) range of 5–105 MPa. Permeabilities and seismic velocities decrease with proximity to the PSZ with permeabilities ranging from 10−17 to 10−21 m2 and Vp and Vs ranging from 4400 to 5900 m/s in the ultramylonites/cataclasites and 3900 to 4200 m/s at the PSZ. In comparison with intact country rock protoliths, the highly variable cataclastic structures and secondary phyllosilicates and carbonates have resulted in an overall reduction in permeability and seismic wave velocity, as well as a reduction in anisotropy within the fault core. These results concur with other similar studies on other mature, tectonic faults in their interseismic period. ©2017. The Authors. 2017 English 21699313 10.1002/2017JB014355 Journal of Geophysical Research: Solid Earth 122 Blackwell Publishing Ltd 6160-6179 Department of Earth Ocean and Ecological Sciences, University of Liverpool, Liverpool, United Kingdom; Department of Geological Sciences, University of Canterbury, Christchurch, New Zealand 8 deep drilling; elastic property; fault zone; hydraulic property; laboratory method; permeability; seismic anisotropy; seismic velocity, Alpine Fault Zone; New Zealand; South Island https://www.scopus.com/inward/record.uri?eid=2-s2.0-85027690011&doi=10.1002%2f2017JB014355&partnerID=40&md5=77ed6dadf802813cba26ab4b59d17c1e cited By 18 M.J. Allen D. Tatham D.R. Faulkner E. Mariani C. Boulton article Chamberlain20171443 The Deep Fault Drilling Project (DFDP) is a multinational scientific drilling effort to study the evolution, structure, and seismogenesis of the Alpine fault, New Zealand, via in situ measurements of fault rock properties. The second phase of drilling (DFDP-2), undertaken in the Whataroa Valley in late 2014, was intended to intersect the Alpine fault at a depth of around 1 km. In conjunction with the drilling and on-site science activities, a real-time seismic monitoring scheme and traffic-light response protocol were established to detect, locate, and if necessary respond to seismicity within 30 km of the drill site. This network was operated around the clock between late August 2014 and early January 2015, and we detected and located 493 earthquakes of ML 0.6-4.2. None of these earthquakes occurred within 3 km of the drill site, and nor did any of the seismicity detected require changes to drilling operations. The monitoring was undertaken using open-source software operated by an international team of 16 seismologists (including eight postgraduate students) working in 7 institutions and 3 countries to provide rapid on- and off-site manual checking and relocating of events. The team's standard response time between detection and final location was less than 30 min under normal background seismicity conditions and up to 1 hr during swarm activity and for low-priority, distant (≥30 km epicentrally from the drill site) earthquakes. This article documents the methodology, infrastructure, protocols, outcomes, and key lessons of this monitoring. © 2017 by the Seismological Society of America. 2017 English 08950695 10.1785/0220170095 Seismological Research Letters 88 Seismological Society of America 1443-1454 School of Geography, Environment and Earth Sciences, Victoria University of Wellington, P.O. Box 600, Wellington, 6140, New Zealand; Institute of Earth Science and Engineering, University of Auckland, Auckland, 1010, New Zealand; Science Centre, University of Auckland, 23 Symonds Street, Auckland, 1010, New Zealand; GNS Science, P.O. Box 30-368, Lower Hutt, 5040, New Zealand; Department of Geoscience, University of Wisconsin-Madison, 1215W Dayton Street, Madison, WI 53706, United States; Research Center for Prediction of Earthquakes and Volcanic Eruptions, Graduate School of Science, Tohoku University, Sendai, 980-8578, Japan; National Research Institute for Earth Science and Disaster Prevention, 3-1, Tennodai, Tsukuba Ibaraki, 305-0006, Japan; Department of Geology, University of Otago, Dunedin, 9054, New Zealand; Goethe University Frankfurt, Institute of Geosciences, Altenhöferallee 1, Frankfurt, 60438, Germany 6 Drills; Faulting; Geophysics; Open source software; Open systems; Rock drilling; Software engineering, Drilling operation; Earthquake monitoring; In-situ measurement; International team; Postgraduate students; Science activities; Scientific drilling; Seismic monitoring, Earthquakes, drilling; earthquake magnitude; earthquake swarm; fault; seismicity, Alpine Fault Zone; New Zealand; South Island; West Coast [South Island]; Whataroa https://www.scopus.com/inward/record.uri?eid=2-s2.0-85034091878&doi=10.1785%2f0220170095&partnerID=40&md5=7e82143d3126d3323e8961e08cab5486 cited By 2 C.J. Chamberlain C.M. Boese J.D. Eccles M.K. Savage L.-M. Baratin J. Townend A.K. Gulley K.M. Jacobs A. Benson S. Taylor-Offord C. Thurber B. Guo T. Okada R. Takagi K. Yoshida R. Sutherland V.G. Toy article Torfstein2017 We report the δ34 S and δ18 O(SO4) measured in gypsum, pyrite, and elemental sulfur through a 456-m thick sediment core from the center of the Dead Sea, representing the last ∼200 kyrs, as well as from the exposed glacial outcrops of the Masada M1 section located on the margins of the modern Dead Sea. The results are used to explore and quantify the evolution of sulfur microbial metabolism in the Dead Sea and to reconstruct the lake’s water column configuration during the late Quaternary. Layers and laminae of primary gypsum, the main sulfur-bearing mineral in the sedimentary column, display the highest δ34 S and δ18 O(SO4) in the range of 13–28 and 13–30%, respectively. Within this group, gypsum layers deposited during interglacials display lower δ34 S and δ18 O(SO4) relative to those associated with glacial or deglacial stages. The reduced sulfur phases, including chromiumreducible sulfur, andsecondary gypsumcrystals are characterizedby extremely low δ34 S in the range of −27 to +7%. The δ18 O(SO4) of the secondary gypsum in the M1 outcrop ranges from 8 to 14%. The relationship between δ34 S and δ18 O(SO4) of primary gypsumsuggests that the rate of microbial sulfate reduction was lower during glacial relative to interglacial times. This suggests that the freshening of the lake during glacial wet intervals, and the subsequent rise in sulfate concentrations, slowed the rate of microbial metabolism. Alternatively, this could imply that sulfate-driven anaerobic methane oxidation, the dominant sulfur microbial metabolism today, is a feature of the hypersalinity in the modern Dead Sea. Sedimentary sulfides are quantitatively oxidized during epigenetic exposure, retaining the lower δ34 S signature; the δ18 O(SO4) of this secondary gypsum is controlled by oxygen atoms derived equally from atmospheric oxygen and from water, which is likely a unique feature in this hyperarid environment. © 2017 Torfstein and Turchyn. 2017 English 22966463 10.3389/feart.2017.00062 Frontiers in Earth Science 5 Frontiers Media S.A. Institute of Earth Sciences, Hebrew University of Jerusalem, Jerusalem, Israel; Interuniversity Institute for Marine Sciences, Eilat, Israel; Department of Earth Sciences, University of Cambridge, Cambridge, United Kingdom Glacial geology; Gypsum; Lakes; Metabolism; Oxidation; Oxygen; Paleolimnology; Pyrites; Sedimentology, Dead sea; Isotope fractionation; Sulfate reduction; Sulfates; Sulfide oxidation, Sulfur compounds, gypsum; outcrop; oxygen isotope; pyrite; sediment core; sulfate-reducing bacterium; sulfur, Dead Sea https://www.scopus.com/inward/record.uri?eid=2-s2.0-85027696689&doi=10.3389%2ffeart.2017.00062&partnerID=40&md5=0949aaef73b47be8a010e0a9d703b6f0 cited By 6 A. Torfstein A.V. Turchyn article Kitagawa2017383 This study establishes the chronological framework of the sedimentary sequence deposited Dead Sea, ICDP 5017-1, Radiocarbon chronology during the past 50 ka at the deepest part of the Dead Sea (the ICDP 5017-1 site), which was recovered by the Dead Sea Deep Drilling Project (DSDDP) under the auspices of the International Continental Scientific Drilling Program (ICDP). The age-depth model is constructed using 3814C dates of terrestrial plant remains in a composite 150-m-long profile, generated by anchoring 32 marker layers identified in five cores. The sedimentary records at the ICDP 5017-1 site fills gaps in those obtained from the exposed sections at the high margins of the lake, particularly in times of lake-level retreat, and allows for a high-resolution comparison between the lake’s margins and deepest floor. © 2017 by the Arizona Board of Regents on behalf of the University of Arizona. 2017 English 00338222 10.1017/RDC.2016.120 Radiocarbon 59 Cambridge University Press 383-394 Graduate School of Environmental Studies, Nagoya University, Chikusa-ku, Nagoya, 464-8601, Japan; Institute for Space-Earth Environmental Research (ISEE), Nagoya University, Nagoya, Japan; Geological Survey of Israel, 30 Malkhe Israel St., Jerusalem, 95501, Israel; Lamont-Doherty Earth Observatory and Department of Earth and Environmental Sciences, Columbia University, 61 Route 9W, Palisades, NY 10964, United States; The Fredy and Nadine Hermann Institute of Earth Sciences, The Hebrew University, Edmond J. Safra Campus, Jerusalem, 91904, Israel 2 carbon isotope; chronology; Deep Sea Drilling Project; lacustrine environment; lake level; radiocarbon dating; sedimentary sequence; terrestrial environment, Dead Sea https://www.scopus.com/inward/record.uri?eid=2-s2.0-85018412638&doi=10.1017%2fRDC.2016.120&partnerID=40&md5=9f889af078009bbdd1183ba58e0e59ae cited By 27 H. Kitagawa M. Stein S.L. Goldstein T. Nakamura B. Lazar DSDDP Scientific Party article Artemieva201710 Potentially hazardous asteroids and comets have hit Earth throughout its history, with catastrophic consequences in the case of the Chicxulub impact. Here we reexamine one of the mechanisms that allow an impact to have a global effect—the release of climate-active gases from sedimentary rocks. We use the SOVA hydrocode and model ejected materials for a sufficient time after impact to quantify the volume of gases that reach high enough altitudes (&gt; 25 km) to have global consequences. We vary impact angle, sediment thickness and porosity, water depth, and shock pressure for devolatilization and present the results in a dimensionless form so that the released gases can be estimated for any impact into a sedimentary target. Using new constraints on the Chicxulub impact angle and target composition, we estimate that 325 ± 130 Gt of sulfur and 425 ± 160 Gt CO2 were ejected and produced severe changes to the global climate. ©2017. American Geophysical Union. All Rights Reserved. 2017 10.1002/2017GL074879 Geophysical Research Letters 44 10,180-10,188 Planetary Science Institute, Tucson, AZ, United States; Department of Earth Science and Engineering, Imperial College London, London, United Kingdom 20 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85034048486&doi=10.1002%2f2017GL074879&partnerID=40&md5=9b0a881b45d734a2174e2d5e08b3ed7c cited By 60 N. Artemieva J. Morgan Expedition 364 Science Party article Galić2017135 Multiple sulfur isotope variability in Archean sedimentary rocks provides constraints on the composition of the Earth's earliest atmosphere. The magnitude and sign of mass-independent anomalies reflect not only atmospheric processes, but also transformations due to the Archean marine sulfur cycle prior to preservation into sedimentary pyrite. The processes affecting the Archean marine sulfur cycle and the role of microbial or abiotic redox reactions during pyrite formation remain unclear. Here we combine iron (Fe) and multiple sulfur (S) isotope data in individual pyrite grains with petrographic information and a one-dimensional reactive transport model, to investigate the sources of Fe and S in pyrite formed in a Paleoarchean sedimentary basin. Pyrites were selected from mudstones, sandstones and chert obtained from a drill core in the ca. 3.2 Ga Mapepe and Mendon Formations of the Fig Tree and Onverwacht Groups, respectively, in the Barberton Greenstone Belt, Kaapvaal Craton, South Africa. Pyrite textures and δ56Fe distinguish early-diagenetic pyrite formed with pore-water ferrous iron (disseminated grains with average δ56Fepyrite = 0‰) from late-diagenetic pyrite formed through sulfidation of iron oxide minerals (layered and aggregate forms with average δ56Fepyrite = + 1‰). Mass dependent S isotope variability in pyrite was small (δ34Spyrite ranged from − 1.1 to + 3.3‰) with a correspondingly minor spread in Δ33Spyrite (ranging from + 0.3 to + 2.1‰) and Δ36Spyrite (ranging from − 3.08 to + 0.27‰) that indicates a lack of post-depositional re-working with other distinct sulfur sources. Our combined Fe and S isotope data are most readily explained with pyrite sulfide derived from microbial-reworking of solid elemental S. Iron oxide minerals were necessary to buffer sulfide concentrations and provide favorable conditions for microbial sulfur disproportionation to proceed. The lack of a negative Δ33S signal indicates that pyrite from relatively deep marine diagenetic environments only partially records the products of atmospheric photolysis, consistent with low sulfate concentrations in the Paleoarchean ocean. © 2016 Article 2017 English 00092541 10.1016/j.chemgeo.2016.12.006 Chemical Geology 449 Elsevier B.V. 135 – 146 Barberton Greenstone Belt; Kaapvaal Craton; Ficus (angiosperm); Earth atmosphere; Iron; Iron oxides; Isotopes; Oxide minerals; Photolysis; Redox reactions; Sedimentary rocks; Sedimentology; Sulfur; Sulfur compounds; Composition of the Earth; Fe isotopes; Greenstone belts; Low sulfate concentrations; Multiple sulfur isotopes; Paleoarchean; Reactive transport modeling; S isotopes; Archean; iron; isotopic fractionation; pyrite; sediment chemistry; sedimentary rock; sulfate; sulfur; sulfur isotope; Pyrites https://www.scopus.com/inward/record.uri?eid=2-s2.0-85008214294&doi=10.1016%2fj.chemgeo.2016.12.006&partnerID=40&md5=973ba24b13c01b9d629a776f96b9cdc7 Cited by: 21; All Open Access, Green Open Access Aleksandra Galić Paul R.D. Mason José M. Mogollón Mariëtte Wolthers Pieter Z. Vroon Martin J. Whitehouse article Gao2017229 Today climate change has caused extensive concern of the whole society. Paleoclimate change studies in geological time (including Quaternary and “Deep Time”), in which continental scientific drilling plays a significant role, provide important references to the current climate change. This paper reviews scientific progresses in the study of paleoclimate change in continental scientific drilling projects. In advantage of the continuous sedimentary records acquired by the continental scientific drilling projects, high-resolution chronostratigraphic framework is established and multiple paleoclimatic proxies are applied. With the aim to decipher the process and mechanism of climate change, progresses have been achieved on paleoclimatic reconstructions on different timescales, detailed studies on rapid climate changes, and precise correlation between marine and terrestrial paleoclimatic records. It is predictable that continental scientific drilling will be more influential in the paleoclimate studies in future, especially in deep-time greenhouse climate studies. © 2017, Editorial Office of Earth Science Frontiers. All right reserved. Review 2017 Chinese 10052321 10.13745/j.esf.2017.01.015 Earth Science Frontiers 24 Science Frontiers editorial department 229 – 241 1 Greenhouses; Sedimentology; Continental scientific drillings; Greenhouse climates; Paleoclimate studies; Paleoclimates; Paleoclimatic reconstruction; Paleoclimatic record; Rapid climate change; Sedimentary records; Climate change https://www.scopus.com/inward/record.uri?eid=2-s2.0-85014311391&doi=10.13745%2fj.esf.2017.01.015&partnerID=40&md5=03e0f61ce9aa4d2df9d80de0ea173622 Cited by: 10 Yuan Gao Chengshan Wang Yongjian Huang Bin Hu article Vuillemin2017 Extracellular DNA is ubiquitous in soil and sediment and constitutes a dominant fraction of environmental DNA in aquatic systems. In theory, extracellular DNA is composed of genomic elements persisting at different degrees of preservation produced by processes occurring on land, in the water column and sediment. Extracellular DNA can be taken up as a nutrient source, excreted or degraded by microorganisms, or adsorbed onto mineral matrices, thus potentially preserving information from past environments. To test whether extracellular DNA records lacustrine conditions, we sequentially extracted extracellular and intracellular DNA from anoxic sediments of ferruginous Lake Towuti, Indonesia. We applied 16S rRNA gene Illumina sequencing on both fractions to discriminate exogenous from endogenous sources of extracellular DNA in the sediment. Environmental sequences exclusively found as extracellular DNA in the sediment originated from multiple sources. For instance, Actinobacteria, Verrucomicrobia, and Acidobacteria derived from soils in the catchment. Limited primary productivity in the water column resulted in few sequences of Cyanobacteria in the oxic photic zone, whereas stratification of the water body mainly led to secondary production by aerobic and anaerobic heterotrophs. Chloroflexi and Planctomycetes, the main degraders of sinking organic matter and planktonic sequences at the water-sediment interface, were preferentially preserved during the initial phase of burial. To trace endogenous sources of extracellular DNA, we used relative abundances of taxa in the intracellular DNA to define which microbial populations grow, decline or persist at low density with sediment depth. Cell lysis became an important additional source of extracellular DNA, gradually covering previous genetic assemblages as other microbial genera became more abundant with depth. The use of extracellular DNA as nutrient by active microorganisms led to selective removal of sequences with lowest GC contents. We conclude that extracellular DNA preserved in shallow lacustrine sediments reflects the initial environmental context, but is gradually modified and thereby shifts from its stratigraphic context. Discrimination of exogenous and endogenous sources of extracellular DNA allows simultaneously addressing in-lake and post-depositional processes. In deeper sediments, the accumulation of resting stages and sequences from cell lysis would require stringent extraction and specific primers if ancient DNA is targeted. © 2017 Vuillemin, Horn, Alawi, Henny, Wagner, Crowe and Kallmeyer. Article 2017 English 1664302X 10.3389/fmicb.2017.01440 Frontiers in Microbiology 8 Frontiers Media S.A. JUL cell DNA; RNA 16S; Acidobacteria; Actinobacteria; Alphaproteobacteria; Article; cell count; Chloroflexi; controlled study; cytolysis; Deltaproteobacteria; DNA base composition; DNA extraction; DNA sequence; high throughput sequencing; hydrothermal vent species; Nitrospirae; nonhuman; phylogenetic tree; phylogeny; Planctomycetes; polymerase chain reaction; population abundance; preservation; sediment; Thaumarchaeota; Thermoplasmatales; Verrucomicrobia https://www.scopus.com/inward/record.uri?eid=2-s2.0-85026413976&doi=10.3389%2ffmicb.2017.01440&partnerID=40&md5=b5b219e03dab07bda04a33cac0e4e707 Cited by: 42; All Open Access, Gold Open Access, Green Open Access Aurèle Vuillemin Fabian Horn Mashal Alawi Cynthia Henny Dirk Wagner Sean A. Crowe Jens Kallmeyer conference Zierenberg20171599 The Iceland Deep Drilling Project (IDDP) well IDDP-2 was drilled to 4,659 m in the seawaterrecharged and basalt-hosted Reykjanes geothermal system in Iceland. Spot drill cores were recovered between drilling depths of 3,648.00 m and 4,657.58 m. Temperature and pressure conditions at the base of IDDP-2 were over 426°C and 340 bar immediately following drilling, exceeding the critical point of seawater (406°C and 298 bar). The IDDP-2 cores are the first samples ever recovered from the supercritical roots of an active basalt-hosted hydrothermal system. We provide some preliminary hand sample descriptions, supplemented where possible by thin section petrography and mineral composition analyses for the IDDP-2 drill cores. The cores recovered between 3,648 m and the bottom of the hole at 4,659 m are from a sheeted dike complex and are generally pervasively altered. Despite the extensive alteration, veining is relatively minor and open space veins are very rare. Veins tend to be discontinuous and anastomosing and lack sharp wall rock contacts. They are interpreted as hydrothermal replacement veins formed in the transition zone between brittle and ductile deformation. Important initial findings include the transition from epidote-actinolite alteration to hornblende hornfels alteration at approximately 3,650 m, and the development of hydrothermal biotite in rocks below ∼4,250 m. Felsic (plagiogranite) segregation veins are not common on the Reykjanes peninsula west of the Hengill volcanic system, but are present in minor amounts in most of the dikes cored below ∼4,300 m. Detailed petrographic and geochemical analysis of the samples is on-going. We have also sampled what appears to be hypersaline supercritical/magmatic brine trapped in pore spaces of porous felsite veins and adjacent wall rock, which manifests as a yellow potassium-iron chloride salt that precipitates on the cut edge of the core as pore fluid evaporates. Some of the core at these depths was stained by hematite that formed on the outer core surface by oxidation of ferrous iron in the formation fluid reacting at elevated temperature with oxygenated surface water used as drilling fluid. Further evidence for supercritical brine is apparent in complex fluid inclusions within quartz that contain multiple solid phases. The drill core samples are of immense scientific value for studying chemical conditions in the supercritical roots of high-enthalpy geothermal resources and submarine hydrothermal systems, with implications for improved understanding of ore-forming processes. Conference paper 2017 English 0934412227 01935933 Transactions - Geothermal Resources Council 41 Geothermal Resources Council 1599 – 1615 Department of Earth and Planetary Sciences, University of California, Davis, CA, United States; HS Orka, Orkubraut 3, Svartsengi, Grindavík, 240, Iceland; Department of Earth Sciences, University of California, Riverside, CA, United States; ÍSOR (Iceland GeoSurvey), Grensávegur 9, Reykjavík, 108, Iceland Analytical geochemistry; Basalt; Chlorine compounds; Core drilling; Drilling fluids; Drills; Geothermal fields; Geothermal wells; Hematite; Hydraulic structures; Hydrochemistry; Levees; Lithology; Mica; Petrography; Potassium chloride; Recovery; Silicate minerals; Surface waters; Wall rock, Alteration; Drill core; Enhanced geothermal systems; Geothermal systems; Iceland deep drilling projects; Supercritical, Core samples https://www.scopus.com/inward/record.uri?eid=2-s2.0-85041071902&partnerID=40&md5=8f3731cc71242b3a05aff0690c098400 Cited by: 13 Robert A. Zierenberg Andrew P. G. Fowler Gudmundur Ó. Fridleifsson Wilfred A. Elders TobiaS. B. Weisenberger article Qu2017257 The designed depth of SK2 is 6400 m, which is the deepest scientific drilling in the East Asia. Previous studies shows that the Xujiaweizi Fault Depression is located in the high geotemperature area. However the high geotemperature and possible abnormal pressure are the main challenges for continental scientific drilling. Based on a great deal of geological and geophysical data including regional geological survey, petroleum exploration and exploitation and scientific achievements in the Songliao Basin, we predicted the bottom hole temperature, formation pressure and formation fracture pressure of target strata of SK2. According to the relationship between depth and present geotemperatures, geothermal gradients, we predicted the bottom hole geotemperature of SK2 probably range from 238.83℃ to 265.11℃. According to the relationship between depth and formation pressures, and calculated results using DrillWorks, we estimated the formation pressure of Yingcheng Formation, Shahezi Formation and Huoshiling Formation to the bottom of the hole in the range of 30.54-37.72 MPa, 33.22-59.52 MPa, 59.52-67.18 MPa, respectively; and the formation fracture pressure range from 52.35 MPa to 58.62 MPa, from 61.88 MPa to 105.68 MPa, from 104.57 MPa to 118.03 MPa, respectively. © 2017, Editorial Office of Earth Science Frontiers. All right reserved. Article 2017 Chinese 10052321 10.13745/j.esf.2017.01.017 Earth Science Frontiers 24 Science Frontiers editorial department 257 – 264 1 Forecasting; Geology; Petroleum prospecting; Bottom hole; Bottom hole temperatures; Continental scientific drillings; Cretaceous; Formation pressure; Scientific achievements; Songliao basin; Xujiaweizi Fault Depression; Fracture https://www.scopus.com/inward/record.uri?eid=2-s2.0-85014401003&doi=10.13745%2fj.esf.2017.01.017&partnerID=40&md5=9c86f8c011e4bb72b795a5aa2791af26 Cited by: 8 Xuejiao Qu Liwei Yang Xuan Xue Youfeng Gao Pujun Wang conference Kessler20171474 Empirical, core-based, predictive correlations for the calculation of uniaxial compressive strength (UCS) were developed from compressive sonic velocity measurements (55 whole core samples) and porosity, density, and unconfined compressive tests (110 whole core samples). The samples were collected at 55 different depths in a 550 m (1800 ft) interval of core from the MH-2 borehole located in southern Idaho, USA. The western Snake River Plain is a known region of high heat flow and the borehole was drilled into a potential geothermal reservoir characterized by artesian flow of high-temperature (~140°C) fluids from fractured basalt. The UCS values were measured in unconfined compressive tests, density and porosity were measured using a He-pycnometer, and p-wave velocities were measured in a pressure vessel under variable confining pressures. We use correlations between density and p-wave velocity (R2 = 0.91), UCS and porosity (R2 = 0.78), and UCS and p-wave velocity (R2 = 0.79) in a method to calculate calibrated UCS from wireline logs. The impact of this predictive correlation is that UCS can be calculated from as little as a bulk density log when sonic logs and core are not available, greatly increasing the number of wells in which we can obtain a local UCS estimate. © 2017 ARMA, American Rock Mechanics Association. 2017 English 9781510857582 51st US Rock Mechanics / Geomechanics Symposium 2017 2 American Rock Mechanics Association (ARMA) 1474-1482 Occidental Petroleum Corporation, Houston, TX, United States; University of Alberta, Edmonton, Canada; Utah State University, Logan, UT, United States Acoustic wave velocity; Core samples; Geothermal fields; Porosity; Radioactivity logging; Rock mechanics; Seismic waves; Wave propagation, Compressive tests; Empirical relationships; Geothermal reservoir; Predictive correlation; Snake river plains; Ultrasonic P-wave velocity; Uniaxial compressive strength; Variable confining pressures, Compressive strength https://www.scopus.com/inward/record.uri?eid=2-s2.0-85047922964&partnerID=40&md5=71b07a2437a1a1cf62e0a1317221a728 cited By 0 J.A. Kessler X. Chen J.P. Evans J.W. Shervais article Tomonaga2017 In closed-basin lakes, sediment porewater salinity can potentially be used as a conservative tracer to reconstruct past fluctuations in lake level. However, until now, porewater salinity profiles did not allow quantitative estimates of past lake-level changes because, in contrast to the oceans, significant salinity changes (e.g., local concentration minima and maxima) had never been observed in lacustrine sediments. Here we show that the salinity measured in the sediment pore water of Lake Van (Turkey) allows straightforward reconstruction of two major transgressions and a major regression that occurred during the last 250 ka. We observed strong changes in the vertical salinity profiles of the pore water of the uppermost 100 m of the sediments in Lake Van. As the salinity balance of Lake Van is almost at steady-state, these salinity changes indicate major lake-level changes in the past. In line with previous studies on lake terraces and with seismic and sedimentological surveys, we identify two major transgressions of up to +105 m with respect to the current lake level at about 135 ka BP and 248 ka BP starting at the onset of the two previous interglacials (MIS5e and MIS7), and a major regression of about-200 m at about 30 ka BP during the last ice age. © 2017 The Author(s). 2017 English 20452322 10.1038/s41598-017-00371-w Scientific Reports 7 Nature Publishing Group Eawag Swiss Federal Institute of Aquatic Science and Technology, Department of Water Resources and DrinkingWater, Überlandstrasse 133, Dübendorf, 8600, Switzerland; Atmosphere and Ocean Research Institute, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa-shi, Chiba, 277-8564, Japan; Institute of Geological Sciences, University of Bern, Baltzerstrasse 1+3, Bern, 3012, Switzerland; Geological Institute, Swiss Federal Institute of Technology (ETH), Zürich, 8092, Switzerland; Ruhr-University Bochum, Universitätstrasse 150, Bochum, 44801, Germany; Eawag Swiss Federal Institute of Aquatic Science and Technology, Department Surface Water Research and Management, Seestrasse 79, Kastanienbaum, 6047, Switzerland; Institute of Biogeochemistry and Pollutant Dynamics, Swiss Federal Institute of Technology (ETH), Zürich, 8092, Switzerland; Eawag Swiss Federal Institute of Aquatic Science and Technology, Department Surface Water Research and Management, Überlandstrasse 133, Dübendorf, 8600, Switzerland; Oeschger Centre for Climate Change Research, University of Bern, Falkenplatz 16, Bern, 3012, Switzerland; Institute of Geochemistry and Petrology, Swiss Federal Institute of Technology (ETH), Zurich, 8092, Switzerland 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85017145585&doi=10.1038%2fs41598-017-00371-w&partnerID=40&md5=8ba26f64512e89710a91e3356178d953 cited By 21 Y. Tomonaga M.S. Brennwald D.M. Livingstone O. Kwiecien M.-E. Randlett M. Stockhecke K. Unwin F.S. Anselmetti J. Beer G.H. Haug C.J. Schubert M. Sturm R. Kipfer article Zhao2017915 As the main borehole of the China Cretaceous Continental Scientific Drilling Project, the SK-2 east borehole was drilled to obtain in-situ multi-information of geophysics and investigate the paleoclimatic and environmental changes. A study based on continuous geophysical logs facilitates achievement of scientific goals, such as the establishment of the typical petrophysical properties for Songliao basin and other similar basins, analysis of sedimentary environment, resource exploration, geothermal system research, and long-term observation and fluid experiments on deep strata. Both conventional logs and microresistivity imaging logs of the Cretaceous Quantou formation have been acquired. Porosity spectra from microresistivity imaging logs are obtained by using the Archie equation. Based on analysis of porosity spectrum features, we divide the porosity spectra of K1q in the SK-2 east borehole into twelve configurations according to the location and combination of peaks to characterize different pore structure. The porosity spectra of K1q in the SK-2 east borehole are dominated by unimodal distribution indicating more primary porosity. Five layers dominated by unimodal distribution are considered for performing long-term observations and fluid experiments on aspects of depth, thickness or petrophysical properties. By comparing spectrum features, porosity spectrum can be used to reflect the heterogeneity and analyze the pore structure of clastic strata. Layered strata will produce complicated porosity spectra as secondary porosity will. It is better to combine porosity spectra with microresistivity image to study secondary porosity. The decline of the porosity heterogeneity in the SK-2 east borehole is demonstrated by two parameters, φvk and W from porosity spectra, which can indicate the sedimentary environment. Moreover, porosity spectra in clastic strata is favorable for determining lithology and sedimentary environment when combined with microresistivity images. © 2017 Elsevier B.V. 2017 English 09204105 10.1016/j.petrol.2017.09.067 Journal of Petroleum Science and Engineering 159 Elsevier B.V. 915-926 Key Laboratory of Geo-detection (China University of Geosciences, Beijing), Ministry of Education, Beijing, 100083, China; School of Geophysics and Information Technology, China University of Geosciences, Beijing, 100083, China; Research Institute of Petroleum Exploration & Development, PetroChina, Beijing, 100083, China; Development and Research Center, China Geological Survey, Beijing, 100037, China Boring; Geophysics; Geothermal fields; Geothermal logging; Lithology; Pore structure; Porosity; Sedimentology; Spectrum analysis; Structural geology, Clastic strata; Continental scientific drillings; Imaging log; Long term observations; Petrophysical properties; Pore structure characterizations; Sedimentary environment; Songliao basin, Well logging, borehole logging; clastic rock; drilling; environmental change; lithology; paleoclimate; porosity, China; Songliao Basin https://www.scopus.com/inward/record.uri?eid=2-s2.0-85042182466&doi=10.1016%2fj.petrol.2017.09.067&partnerID=40&md5=72c7ac2e5c1e9ad5b62975cadcdf1b1b cited By 6 J. Zhao C. Zou H. Fu L. Xiao C. Peng Y. Niu article Levy2017315 Pore fluids extracted from a 456 m sediment core, recovered within the framework of a multinational and International Continental Scientific Drilling Program (ICDP) co-sponsored effort at the bottom of the terminal Dead Sea, recorded the chemical variations in the deep lake over the past 220 k.y. Mg2+ and Br- were shown to be conservative in the pore fluids, increasing in concentration during interglacial periods, diluting during glacials, and providing excellent proxies for deep lake net water balance changes. Furthermore, the Na/Cl ratio recorded the process of halite precipitation and dissolution induced by these hydrological changes. Mg2+ and Br- records follow a glacialinterglacial pattern, such as observed in atmospheric CO2 concentrations and global sea-surface temperatures, albeit with a phase offset. At the end of the last interglacial (ca. 116 ka), there is a delay in onset of dilution of the deep lake, most likely due to the limnological transition from holomictic to meromictic conditions. The increase in deep lake concentrations at Last Glacial Termination I is delayed as a result of freshwater input into the deep lake during the cooler Younger Dryas period. There is a persistent relationship between precipitation in the watershed and North Atlantic sea-surface temperatures, similar to conditions observed over the past instrumental record. Deviations from the long-term trends occurred during interglacial periods, Marine Isotope Stages MIS 5e and MIS 1, when the deep Dead Sea was significantly diluted, and coincided with Mediterranean sapropel layers S5 and S1. © 2017 The Authors. 2017 English 00917613 10.1130/G38685.1 Geology 45 Geological Society of America 315-318 Department of Geological and Environmental Sciences, Ben-Gurion University of the Negev, Beer Sheva, 8410501, Israel; Geological Survey of Israel, 30 Malkhe Israel Street, Jerusalem, 95501, Israel; The Fredy and Nadine Herrmann Institute of Earth Sciences, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat Ram, Jerusalem, 91904, Israel; Department of Hydrology and Microbiology, Zuckerberg Center, Ben-Gurion University of the Negev, Sede Boker, 8499000, Israel 4 Atmospheric temperature; Bromine; Carbon dioxide; Climate change; Drilling fluids; Glacial geology; Magnesium; Oceanography; Submarine geophysics; Surface properties; Surface waters, Chemical variations; Continental scientific drillings; Global climate changes; Hydrological changes; Interglacial periods; Last glacial terminations; Marine isotope stages; Sea surface temperature (SST), Lakes, climate variation; Last Glacial; paleoclimate; porewater; precipitation (climatology); sediment core; water budget; water chemistry, Dead Sea https://www.scopus.com/inward/record.uri?eid=2-s2.0-85015207606&doi=10.1130%2fG38685.1&partnerID=40&md5=ea14e0e90bd9f5286e895b818a1a8b76 cited By 16 E.J. Levy M. Stein B. Lazar I. Gavrieli Y. Yechieli O. Sivan article Townend20174709 Fault rock assemblages reflect interaction between deformation, stress, temperature, fluid, and chemical regimes on distinct spatial and temporal scales at various positions in the crust. Here we interpret measurements made in the hanging-wall of the Alpine Fault during the second stage of the Deep Fault Drilling Project (DFDP-2). We present observational evidence for extensive fracturing and high hanging-wall hydraulic conductivity (∼10−9 to 10−7 m/s, corresponding to permeability of ∼10−16 to 10−14 m2) extending several hundred meters from the fault's principal slip zone. Mud losses, gas chemistry anomalies, and petrophysical data indicate that a subset of fractures intersected by the borehole are capable of transmitting fluid volumes of several cubic meters on time scales of hours. DFDP-2 observations and other data suggest that this hydrogeologically active portion of the fault zone in the hanging-wall is several kilometers wide in the uppermost crust. This finding is consistent with numerical models of earthquake rupture and off-fault damage. We conclude that the mechanically and hydrogeologically active part of the Alpine Fault is a more dynamic and extensive feature than commonly described in models based on exhumed faults. We propose that the hydrogeologically active damage zone of the Alpine Fault and other large active faults in areas of high topographic relief can be subdivided into an inner zone in which damage is controlled principally by earthquake rupture processes and an outer zone in which damage reflects coseismic shaking, strain accumulation and release on interseismic timescales, and inherited fracturing related to exhumation. © 2017. American Geophysical Union. All Rights Reserved. Article 2017 English 15252027 10.1002/2017GC007202 Geochemistry, Geophysics, Geosystems 18 Blackwell Publishing Ltd 4709 – 4732 School of Geography, Environment and Earth Sciences, Victoria University of Wellington, Wellington, New Zealand; GNS Science, Lower Hutt, New Zealand; Department of Geology, University of Otago, Dunedin, New Zealand; Université Grenoble-Alpes, Université Savoie Mont Blanc, CNRS, IRD, IFSTTAR, ISTerre, Grenoble, France; Géosciences Montpellier, Université de Montpellier, CNRS, Montpellier, France; Department of Ocean & Earth Science, University of Southampton, Southampton, United Kingdom; Department of Geoscience, University of Wisconsin-Madison, Madison, WI, United States; Department of Physics, University of Alberta, Edmonton, AB, Canada; School of Environmental Sciences, University of Liverpool, Liverpool, United Kingdom; Department of Earth Sciences, University of California, Riverside, CA, United States; Department of Physics, University of Auckland, Auckland, New Zealand; School of Geology and Geophysics, University of Oklahoma, Norman, OK, United States; School of Environment, University of Auckland, Auckland, New Zealand; GNS Science, Dunedin, New Zealand; Schlumberger Fiber-Optic Technology CentreHampshire, United Kingdom; Department of Earth and Space Science, Osaka University, Osaka, Japan; Department of Geosphere Sciences, Yamaguchi University, Yamaguchi, Japan; Kochi Institute for Core Sample Research, Japan Agency for Marine-Earth Science and Technology, Kochi, Japan; Graduate School of Engineering, Kyoto University, Kyoto, Japan; Department of Earth and Planetary Sciences, McGill University, Montreal, QC, Canada; Curtin University, Perth, WA, Australia; ETH Zurich, Zurich, Switzerland; Department of Geology, Shinshu University, Matsumoto, Japan; Faculty of Geosciences, HPT Laboratory, Utrecht University, Utrecht, Netherlands; Department of Earth Science and Technology, Akita University, Akita City, Japan; GFZ German Research Centre for Geosciences, Telegrafenberg, Potsdam, Germany; Geological Survey of Japan, AIST, Tsukuba, Japan; Department of Geosciences, Pennsylvania State University, University Park, PA, United States 12 Earthquakes; Fracture; Geophysics; Groundwater; Hydrogeology; Topography; Transport properties, Damage zones; Earthquake rupture process; Fault zone; Petrophysical datum; Petrophysics; Seismogenesis; Spatial and temporal scale; Strain accumulations, Faulting, coseismic process; earthquake rupture; exhumation; fault zone; heat transfer; hydrogeology; petrochemistry; seismogram; topography, Alpine Fault Zone; New Zealand; South Island https://www.scopus.com/inward/record.uri?eid=2-s2.0-85039555576&doi=10.1002%2f2017GC007202&partnerID=40&md5=cf411868bab0fd6e2c3df519cae0f670 Cited by: 36; All Open Access, Bronze Open Access, Green Open Access John Townend Rupert Sutherland Virginia G. Toy Mai-Linh Doan Bernard Célérier Cécile Massiot Jamie Coussens Tamara Jeppson Lucie Janku-Capova Léa Remaud Phaedra Upton Douglas R. Schmitt Philippe Pezard Jack Williams Michael John Allen Laura-May Baratin Nicolas Barth Leeza Becroft Carolin M. Boese Carolyn Boulton Neil Broderick Brett Carpenter Calum J. Chamberlain Alan Cooper Ashley Coutts Simon C. Cox Lisa Craw Jennifer D. Eccles Dan Faulkner Jason Grieve Julia Grochowski Anton Gulley Arthur Hartog Gilles Henry Jamie Howarth Katrina Jacobs Naoki Kato Steven Keys Martina Kirilova Yusuke Kometani Rob Langridge Weiren Lin Tim Little Adrienn Lukacs Deirdre Mallyon Elisabetta Mariani Loren Mathewson Ben Melosh Catriona Menzies Jo Moore Luis Morales Hiroshi Mori André Niemeijer Osamu Nishikawa Olivier Nitsch Jehanne Paris David J. Prior Katrina Sauer Martha K. Savage Anja Schleicher Norio Shigematsu Sam Taylor-Offord Damon Teagle Harold Tobin Robert Valdez Konrad Weaver Thomas Wiersberg Martin Zimmer article Kliem2017110 Lacustrine sediments retrieved from Laguna Potrok Aike in the framework of the Potrok Aike Maar Lake Sediment Archive Drilling Project (PASADO) offer the possibility to investigate climate variations of the past ~51 cal ka BP in Southern Hemispheric midlatitudes, Argentinean Patagonia. This study focuses on short-term cyclicities in the Ca and magnetic susceptibility data sets between 51 and 15 cal ka BP. The record yields a climate pattern with a periodicity of 1.5 ka during Marine Oxygen Isotope Stage 2 (MIS 2) detected in the Southern Hemisphere from 31 to 17 cal ka BP for the first time. MIS 2 is known for constantly cold temperatures, whereas prominent climate variations paced by a 1.5 ka periodicity occurred during MIS 3. Our study documents that minor latitudinal oscillations of the Southern Hemispheric westerlies and the polar easterlies with a 1.5 ka periodicity also took place during MIS 2. However, we assume that because of a major northward displacement of the Southern Hemispheric westerlies, these oscillations did not sufficiently affect the zone of Circumpolar Deep Waters and an increased greenhouse effect by upwelling of CO2-rich deep waters did not occur. This mechanism illustrates why prominent climate events fail to appear during MIS 2. Copyright © University of Washington. Published by Cambridge University Press, 2017. Article 2017 10.1017/qua.2017.13 Quaternary Research (United States) 88 110 – 120 1 Argentina; Patagonia; Greenhouse effect; Lakes; Magnetic susceptibility; Dansgaard-oeschger events; Frequency Analysis; Laguna potrok aike; Lake sediments; PASADO; Patagonia; climate variation; frequency analysis; lacustrine deposit; marine isotope stage; paleoclimate; Southern Hemisphere; westerly; Sediments https://www.scopus.com/inward/record.uri?eid=2-s2.0-85054518791&doi=10.1017%2fqua.2017.13&partnerID=40&md5=7107acca806e0ae0e15a597f69e7ef68 Cited by: 1; All Open Access, Bronze Open Access Pierre Kliem Henrike Baumgarten Catalina Gebhardt Annette Hahn Christian Ohlendorf Bernd Zolitschka article Albini20171663 The area of the western Gulf of Corinth around the city of Aigio (Achaea, northwest Peloponnese, Greece) represents an international pilot site for continuous monitoring and multidisciplinary research on earthquake processes. In the framework of the ANR-SISCOR Corinth Rift Laboratory project (2011–2014), a thorough reappraisal of the five largest (Mw >6) eighteenth–nineteenth century earthquakes was performed, namely those of 14 May 1748, 23 August 1817, 26 December 1861, 9 September 1888, and 25 August 1889. Written observations of earthquake effects were looked into in their original version and language and were placed in the context from which they originated, to avoid the translations and digests on which previous seismological studies had relied. Earthquake records were traced for 108 different localities, and 143 macroseismic intensities in European Macroseismic Scale 1998 (EMS-98) have been assigned. Earthquake-related geological phenomena have been identified and carefully mapped, to be used as a further constraint of the location and magnitude of the associated earthquakes. Finally, new parameters for the studied earthquakes have been assessed with two separate and independent strategies to quantify epistemic uncertainties. In conclusion, the 1748, 1817, and 1888 earthquakes were located in the area of Aigio; the 1861 earthquake is reckoned to be the largest in the area, with an epicentral location at sea; whereas the 1889 earthquake has been relocated to the northwest in mainland Greece, well outside the Gulf of Corinth. © 2017, Seismological Society of America. All rights reserved. Article 2017 English 00371106 10.1785/0120160181 Bulletin of the Seismological Society of America 107 Seismological Society of America 1663 – 1687 4 Achaea; Egion; Greece; Gulf of Corinth; Ionian Sea; Mediterranean Sea; Western Greece; Achaea; Geophysics; Location; Uncertainty analysis; Continuous monitoring; Earthquake process; Earthquake records; Epistemic uncertainties; Laboratory project; Macroseismic intensity; Multi-disciplinary research; New parameters; earthquake epicenter; earthquake event; earthquake magnitude; earthquake mechanism; eighteenth century; nineteenth century; paleoseismicity; seismicity; seismology; structural geology; Earthquakes https://www.scopus.com/inward/record.uri?eid=2-s2.0-85030184822&doi=10.1785%2f0120160181&partnerID=40&md5=23f8e67332484245cc617e5dd1be6979 Cited by: 11; All Open Access, Green Open Access Paola Albini Andrea Rovida Oona Scotti Hélène Lyon-Caen article Sangode2017769 A 1248 m long core (KBH 07, 17°18′07″ N; 73°47′28.2″E, 960m above msl) drilled up to basement in the Deccan traps from Koyna region was sampled at ∼10m interval for magnetic mineralogical studies.Analysis of routine rock magnetic parameters (mass specific magnetic susceptibility: χlf, frequency dependence of susceptibility: χfd, susceptibility of anhysteretic remanance: χARM, saturation isothermal remanance: SIRM, remanance coercivty: B(0)CR, SoftIRM, HardIRM, S-Ratio, SIRM/χlf, χARM/χlf) and density (σ, gm/cc) depicted significant higher order temporal variation. The χlf varies between 13 and 309 x 10-8m3/kg and is independent of density variation. The χARM, B(0)CR and S-Ratios indicate majority of SD-PSD ferrimagnets with episodes of MD ferrimagnetic concentration and few hard coercivity components. The giant plagioclase lath bearing (GPB) horizons show highest variability of ferrimagnetic concentration marked by anomalous peaks. Overall the variability of rock magnetic parameters independent of lava flow units suggest that the changeover in magnetic mineral concentration, composition and domain size occur at major episodes in magma composition (e.g., primary source, crustal contamination and fractional crystallization). The studied parameters are therefore examined to mark intervals of (i) magma compositional changes, (ii) zones of oxidative conditions and (iii) rapid/slow cooling intervals demanding detailed petrologic studies. We identified one I order trend, four II order cycles and eight III order cycles for the purpose of correlation. Notable peak in χlf at 650–700m, the changeover in rock magnetic parameters at ∼930 m and ∼280 m can facilitate marker intervals while several higher order variations can be adopted for high resolution correlation to other boreholes in the region. The complex variation in rock magnetic parameters independent of flow units reflect temporal magnitudes of compositional variability, cooling and emplacement history that needs detailed petro-mineralogical attempts; and the present data is useful for high order inter-core correlations under the deep drilling program. © 2017, Geological Society of India. 2017 English 00167622 10.1007/s12594-017-0789-2 Journal of the Geological Society of India 90 Geological Society of India 769-775 Department of Geology, Savitribai Phule Pune University, Pune, 411 007, India; CSIR-National Geophysical Research Institute, Hyderabad, 500 007, India 6 basalt; borehole; Deccan Traps; deep drilling; magnetic mineral; mineralogy, India; Koyna; Maharashtra https://www.scopus.com/inward/record.uri?eid=2-s2.0-85039442337&doi=10.1007%2fs12594-017-0789-2&partnerID=40&md5=5f014cee521a64c21aa9fe2725fa51c5 cited By 7 S.J. Sangode M. Venkateshwarulu R. Mahajan V. Randive article Holtvoeth2017 The impact of past global climate change on local terrestrial ecosystems and their vegetation and soil organic matter (OM) pools is often non-linear and poorly constrained. To address this, we investigated the response of a temperate habitat influenced by global climate change in a key glacial refuge, Lake Ohrid (Albania, Macedonia). We applied independent geochemical and palynological proxies to a sedimentary archive from the lake over the penultimate glacial-interglacial transition (MIS 6-5) and the following interglacial (MIS 5e-c), targeting lake surface temperature as an indicator of regional climatic development and the supply of pollen and biomarkers from the vegetation and soil OM pools to determine local habitat response. Climate fluctuations strongly influenced the ecosystem, however, lake level controls the extent of terrace surfaces between the shoreline and mountain slopes and hence local vegetation, soil development and OM export to the lake sediments. There were two phases of transgressional soil erosion from terrace surfaces during lake-level rise in the MIS 6-5 transition that led to habitat loss for the locally dominant pine vegetation as the terraces drowned. Our observations confirm that catchment morphology plays a key role in providing refuges with low groundwater depth and stable soils during variable climate. © 2017 The Author(s). Article 2017 English 20452322 10.1038/s41598-017-08101-y Scientific Reports 7 Nature Publishing Group 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85027450543&doi=10.1038%2fs41598-017-08101-y&partnerID=40&md5=25e07dcc5d43b3b85b497a35041b90c7 Cited by: 14; All Open Access, Gold Open Access, Green Open Access Jens Holtvoeth Hendrik Vogel Verushka Valsecchi Katja Lindhorst Stefan Schouten Bernd Wagner George A. Wolff article Brounce20178997 The behavior of C, H, and S in the solid Earth depends on their oxidation states, which are related to oxygen fugacity (fO2). Volcanic degassing is a source of these elements to Earth’s surface; therefore, variations in mantle fO2 may influence the fO2 at Earth’s surface. However, degassing can impact magmatic fO2 before or during eruption, potentially obscuring relationships between the fO2 of the solid Earth and of emitted gases and their impact on surface fO2. We show that low-pressure degassing resulted in reduction of the fO2 of Mauna Kea magmas by more than an order of magnitude. The least degassed magmas from Mauna Kea are more oxidized than midocean ridge basalt (MORB) magmas, suggesting that the upper mantle sources of Hawaiian magmas have higher fO2 than MORB sources. One explanation for this difference is recycling of material from the oxidized surface to the deep mantle, which is then returned to the surface as a component of buoyant plumes. It has been proposed that a decreasing pressure of volcanic eruptions led to the oxygenation of the atmosphere. Extension of our findings via modeling of degassing trends suggests that a decrease in eruption pressure would not produce this effect. If degassing of basalts were responsible for the rise in oxygen, it requires that Archean magmas had at least two orders of magnitude lower fO2 than modern magmas. Estimates of fO2 of Archean magmas are not this low, arguing for alternative explanations for the oxygenation of the atmosphere. © 2017, National Academy of Sciences. All rights reserved. 2017 English 00278424 10.1073/pnas.1619527114 Proceedings of the National Academy of Sciences of the United States of America 114 National Academy of Sciences 8997-9002 Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, United States; Department of Earth Sciences, University of California, Riverside, CA 92521, United States 34 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85027855971&doi=10.1073%2fpnas.1619527114&partnerID=40&md5=67d568a9d044f7bfcc2a02f11c1573d1 cited By 88 M. Brounce E. Stolper J. Eiler article Gao2017242 The simulated stratigraphic column of SK2 is the main reference for the whole scientific drilling process bases on the experience of SK1. First of all, the depth of the main formation boundaries was predicted according to structural maps, seismic profiles and adjacent wells. Secondly, we predicted the detail lithology of each member or formation, based on regional stratigraphic-lithologic characteristics, geophysical data, and well Songshen3 and other adjacent wells. Finally, the designed coring horizon, contents, oil, gas and water bearing layers, probable drilling failures etc. were integrated into the comprehensive simulated stratigraphic column of SK2. The depth of the main formation boundaries of SK2 is predicted as below: the top of the 2nd member of Nenjiang Formation (T06) is 950 m, the top of Yaojia Formation (T1) is 1245 m, the top of Quantou Formation (T2) is 1680 m, the top of Denglouku Formation (T3) is 2530 m, the top of Yingcheng Formation (T4) is 2965 m, the top of Shahezi Formation (T4-1) is 3320 m, the top of Huoshiling Formation (T4-2) is 5670 m, and the top of basement (T5) is 6240 m. The lithology of main target strata of SK2 are predicted as follows. Yingcheng Formation can be divided into two parts, and the upper part consists mostly of coarse sand, conglomerate, and glutinite, with mudstone as interlayers, and massive tuff, andesite-basalt and rhyolite, dominated in the lower part. The Shahezi Formation is composed mostly of dark mudstone, with sand, siltstone, silty mudstone, and coal streak as interlayers. The lithology of Huoshiling Formation possibly corresponds to regional stratigraphic-lithologic characteristics, and the upper part is mainly composed of tuff, mudstone, and dacite and andesite, while the lower part consists mostly of dark mudstone, with fine-siltstone and coal streak as interlayers. The basement probably composed of conglomerate and permian-carboniferous “metamorphic rock”, which are probably very high diagenesis or very low-grade metamorphism sedimentary rocks. © 2017, Editorial Office of Earth Science Frontiers. All right reserved. Article 2017 Chinese 10052321 10.13745/j.esf.2017.01.016 Earth Science Frontiers 24 Science Frontiers editorial department 242 – 256 1 Buildings; Lithology; Metamorphic rocks; Sedimentology; Stratigraphy; Well drilling; Continental scientific drillings; Denglouku formations; Low-grade metamorphism; Scientific drilling; Shahezi formations; Songliao basin; Stratigraphic columns; Stratigraphic interfaces; Sedimentary rocks https://www.scopus.com/inward/record.uri?eid=2-s2.0-85014312278&doi=10.13745%2fj.esf.2017.01.016&partnerID=40&md5=af15e34f7e8523647e369be4712d8ad8 Cited by: 12 Youfeng Gao Xuejiao Qu Lijun Jiang Shuxue Wang Pujun Wang article Gupta2017133 Artificial water reservoir triggered earthquakes are now known to have occurred at over 120 sites globally. The part played by the reservoirs in triggering is not exactly known due to lack of near field observations of triggered earthquakes. Koyna, located near the west coast of India, where triggered earthquakes have been occurring since 1962 provides an excellent site for near field observations of the target M ≥ 2 earthquakes. A 6 borehole seismic network has been deployed recently in the Koyna region at depths of 981–1522 m to improve the hypocenter locations. During May–December 2015, a total of 1039 earthquakes of ML ≥ 0.5 were located using the borehole seismic network. The region is also monitored through a dense network of 23 surface broad-band stations. Our analysis indicates a significant improvement in the estimation of absolute locations of earthquakes with errors of the order of ± 300 m, combining both the networks. Based on seismicity, and logistics, a block of 2 × 2 km2 area has been chosen for drilling the first pilot borehole of ~ 3 km depth, where M ≥ 2 earthquakes have been occurring frequently since 2005. © 2016 International Association for Gondwana Research 2017 English 1342937X 10.1016/j.gr.2016.10.014 Gondwana Research 42 Elsevier Inc. 133-139 Council of Scientific and Industrial Research-National Geophysical Research Institute (CSIR-NGRI), Uppal Road, Hyderabad, 500007, India borehole geophysics; borehole logging; broadband data; detection method; drilling; earthquake hypocenter; earthquake magnitude; error analysis; estimation method; reservoir-induced seismicity; site investigation; trigger mechanism, India; Koyna; Maharashtra https://www.scopus.com/inward/record.uri?eid=2-s2.0-85009064333&doi=10.1016%2fj.gr.2016.10.014&partnerID=40&md5=0c9cf091fe670d282fdcf56db2c68196 cited By 20 H.K. Gupta D. Shashidhar C.R. Mahato H.V.S. Satyanarayana K. Mallika N.P. Rao B.S. Maity K. Navitha article Grieve20171 The current record of large-scale impact on Earth consists of close to 200 impact structures and some 30 impact events recorded in the stratigraphic record, only some of which are related to known structures. It is a preservation sample of a much larger production population, with the impact rate on Earth being higher than that of the moon. This is due to the Earth’s larger physical and gravitational cross-sections, with respect to asteroidal and cometary bodies entering the inner solar system. While terrestrial impact structures have been studied as the only source of ground-truth data on impact as a planetary process, it is becoming increasingly acknowledged that large-scale impact has had its effects on the geologic history of the Earth, itself. As extremely high energy events, impacts redistribute, disrupt and reprocess target lithologies, resulting in topographic, structural and thermal anomalies in the upper crust. This has resulted in many impact structures being the source of natural resources, including some worldclass examples, such as gold and uranium at Vredefort, South Africa, Ni-Cu-PGE sulphides at Sudbury, Canada and hydrocarbons from the Campeche Bank, Mexico. Large-scale impact also has the potential to disrupt the terrestrial biosphere. The most devastating known example is the evidence for the role of impact in the Cretaceous-Paleocene (K-Pg) mass extinction event and the formation of the Chicxulub structure, Mexico. It also likely had a role in other, less dramatic, climatic excursions, such as the Paleocene-Eocene-Thermal Maximum (PETM) event. The impact rate was much higher in early Earth history and, while based on reasoned speculation, it is argued that the early surface of the Hadean Earth was replete with massive impact melt pools, in place of the large multiring basins that formed on the lower gravity moon in the same time-period. These melt pools would differentiate to form more felsic upper lithologies and, thus, are a potential source for Hadean-aged zircons, without invoking more modern geodynamic scenarios. The Earth-moon system is unique in the inner solar system and currently the best working hypothesis for its origin is a planetary-scale impact with the proto-Earth, after core formation at ca. 4.43 Ga. Future large-scale impact is a low probability event but with high consequences and has the potential to create a natural disaster of proportions unequalled by other geologic processes and threaten the extended future of human civilization, itself. © 2017 GAC/AGC®. 2017 10.12789/geocanj.2017.44.113 Geoscience Canada 44 1-26 Department of Earth Sciences, University of Western Ontario, 1151 Richmond Street, London, ON N6A 5B7, Canada 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85018348620&doi=10.12789%2fgeocanj.2017.44.113&partnerID=40&md5=170a6a51f561730602fb072c911155a8 cited By 5 R.A.F. Grieve article sharkov2017magmatic 2017 Geoscience Frontiers 8 Elsevier 621--640 4 E Sharkov M Bogina A Chistyakov article Li2017143 Rock magnetic records have been achieved from the Nenjiang Formation of the Songke-1 south core (SK-1s) in the Songliao Basin (972.46-1060.24 m). According to the magnetic records, this sequence is divided into three sections, termed A (972.46-979 m), B (979-1025 m) and C (1025-1060.24 m), respectively. Magnetic susceptibility (MS) and remanence of section A are both controlled by magnetite; while MS of sections B and C is controlled by paramagnetic minerals and their remanence is mainly carried by magnetite. Among the three sections, the concentration of magnetite of section A is the most and that of section B is the least; while the magnetite particles of section A are the coarsest and those of section C are the finest. The magnetic records of the Nenjiang Formation from SK-1s has deciphered the information of the uplift of the basin and the paleoclimatic changes of this area, although reductive diagenesis plays an effect on the sediments of sections B and C and thus produces the A/B boundary. On the one hand, the fluctuation of the magnetic parameters have recorded the periodical paleoclimatic changes. On the other hand, the abrupt variation of the magnetic parameters at the B/C boundary may be related to the alteration of detrital provenances resulting from the uplift of the eastern basin, from south-north to east-west. © 2017, Editorial Office of Earth Science Frontiers. All right reserved. Article 2017 Chinese 10052321 10.13745/j.esf.2017.01.008 Earth Science Frontiers 24 Science Frontiers editorial department 143 – 153 1 Lithology; Magnetic susceptibility; Magnetite; Remanence; Sedimentology; Detrital provenance; Lake level fluctuations; Nenjiang Formation; Reductive diagenesis; Rock magnetism; Songke-1 south core (SK-1s); Magnetism https://www.scopus.com/inward/record.uri?eid=2-s2.0-85014305176&doi=10.13745%2fj.esf.2017.01.008&partnerID=40&md5=f323608dc462ed34200868a773acb0ef Cited by: 1 Haiyan Li Tinghong Zhou Shihong Zhang Guanghong Liu Huaichun Wu Tianshui Yang Kunling Zhao conference Zhang2017 For seismically active fault with relative dense seismic network, seismic tomography using first arrival times from earthquakes is routinely applied to image fault zone structures. To characterize structure discontinuities around the active fault, seismic scattering imaging using scattered waves can be applied. This technique has been extensively used with active seismic sources, especially in oil/gas industry. However, scattering imaging using waveforms from earthquakes is rare. Here we present the imaging results using scattered SH waves from earthquakes around the SAFOD, California. Near vertical reflectors are clearly imaged around the San Andreas fault (SAF), similar to results obtained using scattered P-P waves. However, for strike-slip focal mechanisms for earthquakes along the SAF, first arrival polarities for P waves are different at different regions. In comparison, SH waves have the same polarities. Because wavelength for P waves is longer than S waves, making the resolution of the imaging result is higher when using scattered S waves. For this study, we found coherent phases (scattered SH waves) after direct SH waves. Overall, the imaging results using different types of waves are bery similar, thus supporting the reliability and usefulness of using passive seismic events to image structure discontinuities. 2017 English 9789462822191 10.3997/2214-4609.201701685 79th EAGE Conference and Exhibition 2017 - Workshops European Association of Geoscientists and Engineers, EAGE University of Science and Technology of China, China Petroleum industry; Seismic waves; Shear waves; Strike-slip faults; Structural geology, Earthquake waveforms; Image Structures; Oil/gas industry; San Andreas fault; Scattering imaging; Seismic networks; Seismic tomography; Seismically active faults, Earthquakes https://www.scopus.com/inward/record.uri?eid=2-s2.0-85088771683&doi=10.3997%2f2214-4609.201701685&partnerID=40&md5=2e60891bc29f990bd1d112070be21b07 cited By 0 H. Zhang K. Chang article Krauze2017 The Cheb Basin (NW Bohemia, Czech Republic) is a shallow, neogene intracontinental basin. It is a non-volcanic region which features frequent earthquake swarms and large-scale diffuse degassing of mantle-derived CO2 at the surface that occurs in the form of CO2-rich mineral springs and wet and dry mofettes. So far, the influence of CO2 degassing onto the microbial communities has been studied for soil environments, but not for aquatic systems. We hypothesized, that deep-trenching CO2 conduits interconnect the subsurface with the surface. This admixture of deep thermal fluids should be reflected in geochemical parameters and in the microbial community compositions. In the present study four mineral water springs and two wet mofettes were investigated through an interdisciplinary survey. The waters were acidic and differed in terms of organic carbon and anion/cation concentrations. Element geochemical and isotope analyses of fluid components were used to verify the origin of the fluids. Prokaryotic communities were characterized through quantitative PCR and Illumina 16S rRNA gene sequencing. Putative chemolithotrophic, anaerobic and microaerophilic organisms connected to sulfur (e.g., Sulfuricurvum, Sulfurimonas) and iron (e.g., Gallionella, Sideroxydans) cycling shaped the core community. Additionally, CO2-influenced waters form an ecosystem containing many taxa that are usually found in marine or terrestrial subsurface ecosystems. Multivariate statistics highlighted the influence of environmental parameters such as pH, Fe2+ concentration and conductivity on species distribution. The hydrochemical and microbiological survey introduces a new perspective on mofettes. Our results support that mofettes are either analogs or rather windows into the deep biosphere and furthermore enable access to deeply buried paleo-sediments. © 2017 Krauze, Kämpf, Horn, Liu, Voropaev, Wagner and Alawi. Article 2017 English 1664302X 10.3389/fmicb.2017.02446 Frontiers in Microbiology 8 Frontiers Media S.A. DEC carbon dioxide; helium; hydrogen; iron; mineral water; organic carbon; Actinobacteria; aquatic environment; Article; chromatography by stationary phase; controlled study; correlation analysis; Czech Republic; earthquake; electrical conductivity parameters; environmental factor; freshwater environment; geochemical analysis; hypoxia; isotope analysis; limit of quantitation; mass spectrometry; microbial community; microbiology; multivariate analysis; nonhuman; Proteobacteria; reverse transcription polymerase chain reaction; sequence analysis; soil analysis https://www.scopus.com/inward/record.uri?eid=2-s2.0-85037736645&doi=10.3389%2ffmicb.2017.02446&partnerID=40&md5=1f1be753f5037ec265557da76df0765f Cited by: 17; All Open Access, Gold Open Access, Green Open Access Patryk Krauze Horst Kämpf Fabian Horn Qi Liu Andrey Voropaev Dirk Wagner Mashal Alawi article Schulz2017322 Archean spherule layers, resulting from impacts by large extraterrestrial objects, to date represent the only remnants of the early meteorite, asteroid, and comet bombardment of the Earth. Only few Archean impact debris layers have been documented, all of them embedded in the 3.23–3.47 billion year old successions of the Barberton Greenstone Belt (BGB) in South Africa and the Pilbara Craton in Western Australia. Some of them might be correlated with each other. Given the scarcity of Archean spherule deposits, four spherule layer intersections from the recently recovered BARB5 drill core from the central Barberton Greenstone Belt, analyzed in this study, provide an opportunity to gain new insight into the early terrestrial impact bombardment. Despite being hydrothermally overprinted, siderophile element abundance signatures of spherule-rich samples from the BARB5 drill core, at least in part, retained a meteoritic fingerprint. The impact hypothesis for the generation of the BARB5 spherule layers is supported by correlations between the abundances of moderately (Cr, Co, Ni) and highly siderophile (Re, Os, Ir, Pt, Ru and Pd) elements, whose peak concentrations and interelement ratios are within the range of those for chondrites. Rhenium-Osmium isotope evidence further support the impact hypothesis. Collectively, this study provides evidence for extraterrestrial admixtures ranging between ∼40 and up to 100% to three of the four analyzed BARB5 spherule layers, and a scenario for their genesis involving (i) impact of a chondritic bolide into a sedimentary target, (ii) varying admixtures of meteoritic components to target materials, (iii) spherule formation via condensation in an impact vapor plume, (iv) transportation of the spherules and sedimentation under submarine conditions, followed by (v) moderate post-impact remobilization of transition metals and highly siderophile elements. © 2017 Elsevier Ltd Article 2017 English 00167037 10.1016/j.gca.2017.05.040 Geochimica et Cosmochimica Acta 211 Elsevier Ltd 322 – 340 Australia; Barberton Greenstone Belt; Pilbara Block; Western Australia; Archean; Earth; geochemistry; impact; meteorite; Ocean Drilling Program; remobilization; rhenium-osmium dating; siderophile element; spherule https://www.scopus.com/inward/record.uri?eid=2-s2.0-85020705751&doi=10.1016%2fj.gca.2017.05.040&partnerID=40&md5=19aff9fd4e1ff958a4e64e382810dc5d Cited by: 12 Toni Schulz Christian Koeberl Ambre Luguet David Acken Tanja Mohr-Westheide Seda Ozdemir Wolf Uwe Reimold article Palchan2017168 The drilled Inter-Continental Drilling Project core at the deeps of the Dead Sea reveals thick sequences of halite deposits from the last interglacial period, reflecting prevailing arid conditions in the lake's watershed. Here, we examine sequences of intercalating evaporates (halite or gypsum) and fine-detritus laminae and apply petrographic, micro-X-ray fluorescence, and statistical tools to establish in high-temporal resolution the hydroclimatic controls on the sedimentation in the last interglacial Dead Sea. The time series of the thickness of the best-recovered core sections of the layered halite, detritus, and gypsum reveals periodicities of ~11, 7-8, and 4-5 yr, pointing to a North Atlantic control and possibly solar influence on the hydrology of the Dead Sea watershed during the regionally arid period of the last interglacial period. Similar periodicities were detected in the last glacial and modern sedimentary sequences of the Dead Sea and other archives of the central Levant, indicating a persistent impact of the solar cycles on regional hydrology, possibly through the effects of the North Atlantic Oscillation. © University of Washington. Published by Cambridge University Press, 2017. 2017 English 00335894 10.1017/qua.2016.10 Quaternary Research (United States) 87 Cambridge University Press 168-179 Fredy and Nadine Herrmann Institute of Earth Sciences, Hebrew University, Jerusalem, Givat Ram, 91904, Israel; Geological Survey of Israel, 30 Malkei Israel St., Jerusalem, 95501, Israel; GFZ German Research Center for Geosciences, Section 5.2 Climate Dynamics and Landscape Evolution, Potsdam, 14473, Germany; Department of Marine Geosciences, Charney School of Marine Sciences, University of Haifa, 31905 Mt. Carmel, Haifa, 3498838, Israel 1 Atmospheric pressure; Chloride minerals; Gypsum; Hydrology; Seawater; Sodium chloride; Statistical mechanics; Watersheds, Dead sea; ICDP core; Interglacial; Laminated sediments; Levant; North Atlantic oscillations; Paleoclimates; Solar cycle, Oceanography, deposition; drilling; halite; Last Glacial; Last Interglacial; marine isotope stage; North Atlantic Oscillation; paleoclimate; periodicity; sedimentary sequence; solar cycle, Atlantic Ocean; Atlantic Ocean (North); Dead Sea; Levant; Mediterranean Region https://www.scopus.com/inward/record.uri?eid=2-s2.0-85028867652&doi=10.1017%2fqua.2016.10&partnerID=40&md5=6553d745b429c07fa78a45f3665cd784 cited By 16 D. Palchan I. Neugebauer Y. Amitai N.D. Waldmann M.J. Schwab P. Dulski A. Brauer M. Stein Y. Erel Y. Enzel article Kaneko2017162 Recent laboratory shear-slip experiments conducted on a nominally flat frictional interface reported the intriguing details of a two-phase nucleation of stick-slip motion that precedes the dynamic rupture propagation. This behavior was subsequently reproduced by a physics-based model incorporating laboratory-derived rate-and-state friction laws. However, applying the laboratory and theoretical results to the nucleation of crustal earthquakes remains challenging due to poorly constrained physical and friction properties of fault zone rocks at seismogenic depths. Here we apply the same physics-based model to simulate the nucleation process of crustal earthquakes using unique data acquired during the San Andreas Fault Observatory at Depth (SAFOD) experiment and new and existing measurements of friction properties of SAFOD drill core samples. Using this well-constrained model, we predict what the nucleation phase will look like for magnitude ∼2 repeating earthquakes on segments of the San Andreas Fault at a 2.8 km depth. We find that despite up to 3 orders of magnitude difference in the physical and friction parameters and stress conditions, the behavior of the modeled nucleation is qualitatively similar to that of laboratory earthquakes, with the nucleation consisting of two distinct phases. Our results further suggest that precursory slow slip associated with the earthquake nucleation phase may be observable in the hours before the occurrence of the magnitude ∼2 earthquakes by strain measurements close (a few hundred meters) to the hypocenter, in a position reached by the existing borehole. ©2016. American Geophysical Union. All Rights Reserved. 2017 English 00948276 10.1002/2016GL071569 Geophysical Research Letters 44 Blackwell Publishing Ltd 162-173 GNS Science, Lower Hutt, New Zealand; School of Geology and Geophysics, University of Oklahoma, Norman, OK, United States; Istituto Nazionale di Geofisica e Vulcanologia, Rome, Italy; Department of Earth Sciences, University of Durham, Durham, United Kingdom 1 Core drilling; Drills; Faulting; Friction; Geophysics; Laboratories; Nucleation; Numerical models; Phase meters; Plates (structural components); Slip forming; Stick-slip; Strike-slip faults; Tectonics; Tribology, Earthquake nucleation; Friction parameters; Frictional interface; Physics-based modeling; Rate and state friction; Repeating earthquake; Slow rupture front; Two-phase nucleation, Earthquakes, active fault; earthquake hypocenter; earthquake magnitude; earthquake rupture; experimental study; fault zone; friction; laboratory method; nucleation; numerical model; San Andreas Fault https://www.scopus.com/inward/record.uri?eid=2-s2.0-85010661370&doi=10.1002%2f2016GL071569&partnerID=40&md5=cd009227ad9af728a6846f09735f5306 cited By 7 Y. Kaneko B.M. Carpenter S.B. Nielsen article Cohuo20175 Freshwater ostracodes from the Neotropical-Caribbean region are potentially excellent tools for evolutionary and paleoenvironmental studies but their use is limited, because integrated data in taxonomy, environmental, and geographical preferences of the species at large scale remain unknown. A total of 118 species were recorded in the Neotropical-Caribbean region based on existing literature and results from fieldwork. About 74% of the species are restricted to the region and most of them show limited distributional areas as a consequence of environmental heterogeneity. Based on Parsimony Analysis of Endemicity, five areas of endemism were identified: (1) southern Florida, (2) southern Mexico-northern Central America, (3) Cuba, (4) Lesser Antilles, and (5) northern Venezuela-Aruba-Curacao-Trinidad. The conservation status of these areas was revised and lake ecosystems with endemic taxa were proposed to be included in environmental protection initiatives. Biogeographical analysis showed a strong differentiation between the ostracode faunas of the Neotropical-Caribbean region and the Neotropical-Neogen region. Few exchanges of species were attributed to ecological and geographical barriers such as volcanism and irregular orography. Faunal affinities within the Neotropical-Caribbean region indicated closer relationship between southern Mexico, southern Florida and the Antilles suggesting a common biogeographical history. Middle Central America and Chiapas-Guatemala highlands were discriminated as isolated regions. © 2016, Springer International Publishing Switzerland. Article 2017 English 00188158 10.1007/s10750-016-2747-1 Hydrobiologia 786 Springer International Publishing 5 – 21 1 Crustacea; Ostracoda https://www.scopus.com/inward/record.uri?eid=2-s2.0-84962713883&doi=10.1007%2fs10750-016-2747-1&partnerID=40&md5=d9c193e6de29dcd661b533197058a25e Cited by: 17 Sergio Cohuo Laura Macario-González Liseth Pérez Antje Schwalb article Cai20178664 In this study, we collected samples from subaerial basaltic glassy margins from the second Hawaii Scientific Drilling Project (HSDP2) core. We employed the rigorous “IZZI” method during the paleointensity experiment combined with the stringent “CCRIT” criteria for data selection to obtain 21 robust paleointensity estimates recorded by glassy margins from 20 lava flows. We compared our new results to published paleointensities from the interiors of the lava flows from HSDP2 and found that our data are systematically lower than those from the interiors of the same lava flows. The reasons for the discrepancy in intensity are still unclear, but one possibility that could not be absolutely excluded is the effect of cooling rate on the more slowly cooled lava flow interiors. Although our new data from the glassy margins are lower than those from the lava flow interiors, they are still overall higher than the expected field of the study site calculated from a geocentric axial dipole model with an ancient average field of 42 ZAm2, either because of a long-term local anomaly of the field in Hawaii or an insufficient age distribution of our new data (e.g., missing the time period with low field intensities). ©2017. American Geophysical Union. All Rights Reserved. Article 2017 English 21699313 10.1002/2017JB014683 Journal of Geophysical Research: Solid Earth 122 Blackwell Publishing Ltd 8664 – 8674 11 Hawaii [United States]; United States; basalt; drilling; glass; lava flow https://www.scopus.com/inward/record.uri?eid=2-s2.0-85033592177&doi=10.1002%2f2017JB014683&partnerID=40&md5=bed9bb5f35b83bbca8909bfa2ab56a88 Cited by: 7; All Open Access, Bronze Open Access, Green Open Access S. Cai L. Tauxe G. Cromwell article Lu20178305 Article 2017 10.1002/2017JB014342 Journal of Geophysical Research: Solid Earth 122 8305 – 8325 10 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85033215233&doi=10.1002%2f2017JB014342&partnerID=40&md5=005c892a389697daa1d406873f830f05 Cited by: 40; All Open Access, Bronze Open Access, Green Open Access Yin Lu Nicolas Waldmann G. Ian Alsop Shmuel Marco article Lozhkin20171 Article 2017 10.1016/j.revpalbo.2017.06.004 Review of Palaeobotany and Palynology 246 1 – 13 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85020948133&doi=10.1016%2fj.revpalbo.2017.06.004&partnerID=40&md5=a402c75d43aced9ba3b27d8a6592db78 Cited by: 9 Anatoly V. Lozhkin Pavel S. Minyuk Patricia M. Anderson Ekaterina Yu. Nedorubova Julya V. Korzun article Kiro2017211 Thick halite intervals recovered by the Dead Sea Deep Drilling Project cores show evidence for severely arid climatic conditions in the eastern Mediterranean during the last three interglacials. In particular, the core interval corresponding to the peak of the last interglacial (Marine Isotope Stage 5e or MIS 5e) contains ∼30 m of salt over 85 m of core length, making this the driest known period in that region during the late Quaternary. This study reconstructs Dead Sea lake levels during the salt deposition intervals, based on water and salt budgets derived from the Dead Sea brine composition and the amount of salt in the core. Modern water and salt budgets indicate that halite precipitates only during declining lake levels, while the amount of dissolved Na+ and Cl− accumulates during wetter intervals. Based on the compositions of Dead Sea brines from pore waters and halite fluid inclusions, we estimate that ∼12–16 cm of halite precipitated per meter of lake-level drop. During periods of halite precipitation, the Mg2+ concentration increases and the Na+/Cl− ratio decreases in the lake. Our calculations indicate major lake-level drops of ∼170 m from lake levels of 320 and 310 m below sea level (mbsl) down to lake levels of ∼490 and ∼480 mbsl, during MIS 5e and the Holocene, respectively. These lake levels are much lower than typical interglacial lake levels of around 400 mbsl. These lake-level drops occurred as a result of major decreases in average fresh water runoff, to ∼40% of the modern value (pre-1964, before major fresh water diversions), reflecting severe droughts during which annual precipitation in Jerusalem was lower than 350 mm/y, compared to ∼600 mm/y today. Nevertheless, even during salt intervals, the changes in halite facies and the occurrence of alternating periods of halite and detritus in the Dead Sea core stratigraphy reflect fluctuations between drier and wetter conditions around our estimated average. The halite intervals include periods that are richer and poorer in halite, indicating (based on the sedimentation rate) that severe dry conditions with water availability as low as ∼20% of the present day, continued for periods of decades to centuries, and fluctuated with wetter conditions that spanned centuries to millennia when water availability was ∼50–100% of the present day. These conclusions have potential implications for the coming decades, as climate models predict greater aridity in the region. © 2017 Elsevier B.V. 2017 English 0012821X 10.1016/j.epsl.2017.01.043 Earth and Planetary Science Letters 464 Elsevier B.V. 211-226 Lamont–Doherty Earth Observatory of Columbia University, 61 Route 9W, Palisades, NY 10964, United States; Department of Earth and Environmental Sciences, Columbia University, 61 Route 9W, Palisades, NY 10964, United States; Serveis Cientificotècnics, Universitat de Barcelona, Barcelona, 08028, Spain; Department of Geological and Environmental Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel; Geological Survey of Israel, 30 Malkhe Israel Street, Jerusalem, 95501, Israel; Institute of Earth Sciences, The Hebrew University, Jerusalem, 91904, Israel Brines; Budget control; Climate change; Climate models; Drops; Drought; Flood control; Isotopes; Lakes; Sea level; Sodium chloride; Stratigraphy; Water, Annual precipitation; Climatic conditions; Dead sea; Eastern Mediterranean; Interglacial; Lake levels; Marine isotope stages; Sedimentation rates, Chloride minerals, aridity; drought; extreme event; halite; interglacial; lake level; marine isotope stage; paleoclimate; Quaternary; salt; water budget, Dead Sea; Mediterranean Region https://www.scopus.com/inward/record.uri?eid=2-s2.0-85013782986&doi=10.1016%2fj.epsl.2017.01.043&partnerID=40&md5=a4d5ad356b2e40e4a2fb913649c1e8f4 cited By 39 Y. Kiro S.L. Goldstein J. Garcia-Veigas E. Levy Y. Kushnir M. Stein B. Lazar article Cao2017205 The data of rock-eval and biomarkers in the samples of the Lijiatuozi Section were analyzed for better understanding the paleo-lake environment of the Lower Member 2 of the Qingshankou Formation(K2qn2)in the Songliao Basin. The organic matters (OMs) were mainly originated from aquatic organisms according to plot of hydrogen index (210-773 mg HC/g TOC) and oxygen index (2-188 mg CO2/g TOC) in low maturity source rock. The evolution of paleo-lake environment could be divided into three stages based on geochemical data. In the stage I, low values of gammacerane index and aryl isoprenoid/phenanthrene ratio, corresponding with low ratios of diasterane/sterane and the plot of pristane/phytane and dehydroxyl vitamin-E index, parameters mentioned above all indicated that the lake was considered as being anoxic and brackish water conditions. In the stage II, the occurrence of short time marine incursion was defined by variable contents of 24-n-propyl-cholestanes and 24-i-propyl-cholestanes, leading to semi-deep or deep water environment; seawater intrusion with sea creatures, oxygen, nutrition, organic matter and sulfurous substances, which were helpful with formation of increasing salinity for brackish water and salt water; abundant composition of aryl isoprenoid displayed that stratified lake water was rich in free state of H2S with euphotic zone of anoxia and upward chemocline during this period. However, the lake was dominantly given priority to fresh water to the brackish water deposition with increasing oxygen content at the same time, which suggested that fresh water input increased in the latter stages of stage II. The lake was in high salinity water, anoxia, and the shallow chemocline due to being influenced by semi-arid climate conditions during the sedimentary period of stage III, and turbulent water body was against growth of green sulfur bacteria and preservation of free H2S. © 2017, Editorial Office of Earth Science Frontiers. All right reserved. Article 2017 Chinese 10052321 10.13745/j.esf.2017.01.013 Earth Science Frontiers 24 Science Frontiers editorial department 205 – 215 1 Aquatic organisms; Bacteria; Biogeochemistry; Biological materials; Biology; Biomarkers; Carbon dioxide; Lakes; Lipids; Organic compounds; Oxygen; Water; Anoxic conditions; Geochemical data; Green sulfur bacteria; Salinity; Semi-arid climate; Songliao basin; Stratified waters; Variable content; Salt water intrusion https://www.scopus.com/inward/record.uri?eid=2-s2.0-85014405388&doi=10.13745%2fj.esf.2017.01.013&partnerID=40&md5=9a5c236deed3eeacdc82c721cc77c877 Cited by: 7 Huairen Cao Jianfang Hu Ping'an Peng Dangpeng Xi article Shanmugam201712 At present, there are no criteria to distinguish soft-sediment deformation structures (SSDS) formed by earthquakes from SSDS formed by the other 20 triggering mechanisms (see a companion paper in Vol. 5, No. 4 of this journal by Shanmugam, 2016). Even if one believes that earthquakes are the true triggering mechanism of SSDS in a given case, the story is still incomplete. This is because earthquakes (seismic shocks) are induced by a variety of causes: 1) global tectonics and associated faults (i.e., mid-ocean ridges, trenches, and transform faults); 2) meteorite-impact events; 3) volcanic eruptions; 4) post-glacial uplift; 5) tsunami impact; 6) cyclonic impact; 7) landslides (mass-transport deposits); 8) tidal activity; 9) sea-level rise; 10) erosion; and 11) fluid pumping. These different causes are important for developing SSDS. Breccias are an important group of SSDS. Although there are many types of breccias classified on the basis of their origin, five types are discussed here (fault, volcanic, meteorite impact, sedimentary-depositional, sedimentary-collapse). Although different breccia types may resemble each other, distinguishing one type (e.g., meteorite breccias) from the other types (e.g., fault, volcanic, and sedimentary breccias) has important implications. 1) Meteorite breccias are characterized by shock features (e.g., planar deformation features in mineral grains, planar fractures, high-pressure polymorphs, shock melts, etc.), whereas sedimentary-depositional breccias (e.g., debrites) do not. 2) Meteorite breccias imply a confined sediment distribution in the vicinity of craters, whereas sedimentary-depositional breccias imply an unconfined sediment distribution, variable sediment transport, and variable sediment provenance. 3) Meteorite, volcanic, and fault breccias are invariably subjected to diagenesis and hydrothermal mineralization with altered reservoir quality, whereas sedimentary-depositional breccias exhibit primary (unaltered) reservoir quality. And finally, 4) sedimentary-collapse breccias are associated with economic mineralization (e.g., uranium ore), whereas sedimentary-depositional breccias are associated with petroleum reservoirs. Based on this important group of SSDS with breccias, the current practice of interpreting all SSDS as “seismites” is inappropriate. Ending this practice is necessary for enhancing conceptual clarity and for advancing this research domain. © 2016 China University of Petroleum (Beijing) 2017 10.1016/j.jop.2016.09.001 Journal of Palaeogeography 6 12-44 Department of Earth and Environmental Sciences, The University of Texas at Arlington, Arlington, TX 76019, United States 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85016238193&doi=10.1016%2fj.jop.2016.09.001&partnerID=40&md5=f5a66895c1ed986c488c1d5cf345eb37 cited By 15 G. Shanmugam article Fridleifsson20171 The Iceland Deep Drilling Project research well RN-15/IDDP-2 at Reykjanes, Iceland, reached its target of supercritical conditions at a depth of 4.5 km in January 2017. After only 6 days of heating, the measured bottom hole temperature was 426 °C, and the fluid pressure was 34MPa. The southern tip of the Reykjanes peninsula is the landward extension of the Mid-Atlantic Ridge in Iceland. Reykjanes is unique among Icelandic geothermal systems in that it is recharged by seawater, which has a critical point of 406 °C at 29.8MPa. The geologic setting and fluid characteristics at Reykjanes provide a geochemical analog that allows us to investigate the roots of a mid-ocean ridge submarine black smoker hydrothermal system. Drilling began with deepening an existing 2.5 km deep vertical production well (RN-15) to 3 km depth, followed by inclined drilling directed towards the main upflow zone of the system, for a total slant depth of 4659m (~4.5 km vertical depth). Total circulation losses of drilling fluid were encountered below 2.5 km, which could not be cured using lost circulation blocking materials or multiple cement jobs. Accordingly, drilling continued to the total depth without return of drill cuttings. Thirteen spot coring attempts were made below 3 km depth. Rocks in the cores are basalts and dolerites with alteration ranging from upper greenschist facies to amphibolite facies, suggesting that formation temperatures at depth exceed 450 °C. High-permeability circulation-fluid loss zones (feed points or feed zones) were detected at multiple depth levels below 3 km depth to bottom. The largest circulation losses (most permeable zones) occurred between the bottom of the casing and 3.4 km depth. Permeable zones encountered below 3.4 km accepted less than 5% of the injected water. Currently, the project is attempting soft stimulation to increase deep permeability. While it is too early to speculate on the energy potential of this well and its economics, the IDDP-2 is a milestone in the development of geothermal resources and the study of hydrothermal systems. It is the first well that successfully encountered supercritical hydrothermal conditions, with potential high-power output, and in which on-going hydrothermal metamorphism at amphibolite facies conditions can be observed. The next step will be to carry out flow testing and fluid sampling to determine the chemical and thermodynamic properties of the formation fluids. © Author(s) 2017. 2017 English 18168957 10.5194/sd-23-1-2017 Scientific Drilling 23 Copernicus GmbH 1-12 HS Orka, Svartsengi, Grindavík, 240, Iceland; Department of Earth Sciences, University of California, Riverside, CA 92521, United States; Department of Earth and Planetary Sciences, University of California, Davis, CA 95616, United States; ÍSOR, Grensásvegur 9, Reykjavík, 108, Iceland Drilling fluids; Economics; Geothermal energy; Geothermal fields; Geothermal wells; Seawater; Thermodynamic properties, Bottom hole temperatures; Formation temperature; Geothermal resources; Hydrothermal system; Iceland deep drilling projects; Supercritical condition; Supercritical hydrothermal; Total circulation loss, Rhenium compounds https://www.scopus.com/inward/record.uri?eid=2-s2.0-85036665131&doi=10.5194%2fsd-23-1-2017&partnerID=40&md5=6c3f2329598f2dcb59e984f6eee789f9 cited By 62 G.Ó. Fridleifsson W.A. Elders R.A. Zierenberg A.P. Fowler T.B. Weisenberger B.S. Hararson K.G. Mesfin article Avice2017 Xenon (Xe) is an exceptional tracer for investigating the origin and fate of volatile elements on Earth. The initial isotopic composition of atmospheric Xe remains unknown, as do the mechanisms involved in its depletion and isotopic fractionation compared with other reservoirs in the solar system. Here we present high precision analyses of noble gases trapped in fluid inclusions of Archean quartz (Barberton, South Africa) that reveal the isotopic composition of the paleo-atmosphere at ≈3.3 Ga. The Archean atmospheric Xe is mass-dependently fractionated by 12.9±2.4 ‰ u-1 (± 2σ, s.d.) relative to the modern atmosphere. The lower than today 129 Xe excess requires a degassing rate of radiogenic Xe from the mantle higher than at present. The primordial Xe component delivered to the Earth's atmosphere is distinct from Solar or Chondritic Xe but similar to a theoretical component called U-Xe. Comets may have brought this component to the Earth's atmosphere during the last stages of terrestrial accretion. © 2017 The Author(s). Article 2017 English 20411723 10.1038/ncomms15455 Nature Communications 8 Nature Publishing Group Barberton; Mpumalanga; South Africa; argon; chlorine; inert gas; xenon; atmospheric chemistry; degassing; isotopic composition; isotopic fractionation; noble gas; paleoatmosphere; quartz; solar system; tracer; xenon; Archean; Article; astronomy; atmosphere; comparative study; fractionation; irradiation; thermodynamics; thermogenesis; volumetry https://www.scopus.com/inward/record.uri?eid=2-s2.0-85019584995&doi=10.1038%2fncomms15455&partnerID=40&md5=e0cd3f4dcecf1fcf9eb33f097fe9b4b3 Cited by: 48; All Open Access, Gold Open Access, Green Open Access Guillaume Avice Bernard Marty Ray Burgess inbook waldmann_2017 2017 10.1017/9781316106754.011 Quaternary of the Levant: Environments, Climate Change, and Humans Cambridge University Press Enzel, Yehouda and Bar-Yosef, OferEditors 99–106 Nicolas Waldmann article Toker2017165 This study analyzed multi-channel seismic reflection data from Lake Van, Eastern Anatolia, to provide key information on the structural elements, deformational patterns and overall tectonic structure of the Lake Van basin. The seismic data reveal three subbasins (the Tatvan, northern and Ahlat subbasins) separated by structural ridges (the northern and Ahlat ridges). The Tatvan basin is a tilted wedge-block in the west, it is a relatively undeformed and flat-lying deep basin, forming a typical example of strike-slip sedimentation. Seismic sections reveal that the deeper sedimentary sections of the Tatvan basin are locally folded, gently in the south and more intensely further north, suggesting a probable gravitational “wedge-block” instability, oblique to the northern margin. The northern subbasin, bounded by normal oblique faults, forms a basin-margin graben structure that is elongated in a northeast-southwest direction. The east-west trending Ahlat ridge forms a fault-wedged sedimentary ridge and appears to offset by reverse oblique faults forming as a push-up rhomb horst structure. The Ahlat subbasin is a fault-wedged trough fill that is elongated in the west-east direction and appears as a horst-foot graben formed by the normal oblique faults. The northeast-southwest directed northern ridge is a faulted crestal terrace of a sublacustrine basement block. Its step-like morphology, in response to the downfaulting of the Tatvan basin, as well as its backthrusted appearance, indicates the normal oblique nature of the bounding faults. The lacustrine shelf and slope show distinctive stratigraphic features; progradational deltas, submerged fluvial channels, distorted and collapsed beddings and soft sediment deformation structures, characterizing a highly unstable nature of shelf caused by strong oblique faulting and related earthquakes. The faulting caused uplift of the Çarpanak spur zone, together with the northeastern Erek delta, deformation of deltaic structures and subsequently exposing the shelf and slope areas. The exposed areas are evident in the angular unconformity surface of the Çarpanak basement block with the northeastern Erek delta and thinned sediments. The uplift resulted in the asymmetric depositional emplacement of the southeastern delta that is controlled by a series of ramp anticlines/low angle reverse faults. The Deveboynu subbasin and Varis spur zone form wide fault-controlled depressions with thick sediments that are elongated in the north-south direction. These subbasins appear as a small pull-apart boundary formed by normal oblique faults at the western end of the southeastern delta. © 2017 Elsevier Ltd 2017 English 1464343X 10.1016/j.jafrearsci.2017.01.002 Journal of African Earth Sciences 129 Elsevier Ltd 165-178 Yuzuncu Yıl University, Department of Geophysical Engineering, Zeve Campus, Van, 65080, Turkey; University of Oulu, Sodankylä Geophysical Observatory (SGO-Oulu unit), POB 3000, Oulu, 90014, Finland; Istanbul Technical University, Eurasia Institute of Earth Sciences, Ayazaga Campus, Maslak-Istanbul, Turkey; University of Bremen, Department of Geosciences, Bremen, Germany; Istanbul Technical University, Department of Geophysical Engineering, Ayazaga Campus, Maslak-Istanbul, Turkey; Korea Institute of Geoscience and Mineral Resources (KIGAM), Petroleum and Marine Research Division, Daejeon, 305-305, South Korea; Alfred Wegener Institute for Polar and Marine Research, Bremerhaven, 27515, Germany deformation; graben; normal fault; reverse fault; sedimentation; seismic data; seismic reflection; strike-slip fault; tectonic structure; uplift; vertical seismic profile, Lake Van; Turkey https://www.scopus.com/inward/record.uri?eid=2-s2.0-85009080899&doi=10.1016%2fj.jafrearsci.2017.01.002&partnerID=40&md5=b36f1284d04d122429936e5355346d87 cited By 19 M. Toker A.M.C. Sengor F. Demirel Schluter E. Demirbag D. Cukur C. Imren PaleoVan-Working Group article Sier2017117 One of the major challenges in understanding the evolution of our own species is identifying the role climate change has played in the evolution of hominin species. To clarify the influence of climate, we need long and continuous high-resolution paleoclimate records, preferably obtained from hominin-bearing sediments, that are well-dated by tephro- and magnetostratigraphy and other methods. This is hindered, however, by the fact that fossil-bearing outcrop sediments are often discontinuous, and subject to weathering, which may lead to oxidation and remagnetization. To obtain fresh, unweathered sediments, the Hominin Sites and Paleolakes Drilling Project (HSPDP) collected a ∼216-meter core (WTK13) in 2013 from Early Pleistocene Paleolake Lorenyang deposits in the western Turkana Basin (Kenya). Here, we present the magnetostratigraphy of the WTK13 core, providing a first age model for upcoming HSPDP paleoclimate and paleoenvrionmental studies on the core sediments. Rock magnetic analyses reveal the presence of iron sulfides carrying the remanent magnetizations. To recover polarity orientation from the near-equatorial WTK13 core drilled at 5°N, we developed and successfully applied two independent drill-core reorientation methods taking advantage of (1) the sedimentary fabric as expressed in the Anisotropy of Magnetic Susceptibility (AMS) and (2) the occurrence of a viscous component oriented in the present day field. The reoriented directions reveal a normal to reversed polarity reversal identified as the top of the Olduvai Subchron. From this excellent record, we find no evidence for the ‘Vrica Subchron’ previously reported in the area. We suggest that outcrop-based interpretations supporting the presence of the Vrica Subchron have been affected by the oxidation of iron sulfides initially present in the sediments -as evident in the core record- and by subsequent remagnetization. We discuss the implications of the observed geomagnetic record for human evolution studies. © 2017 Article 2017 English 18711014 10.1016/j.quageo.2017.08.004 Quaternary Geochronology 42 Elsevier B.V. 117 – 129 Kenya; Turkana; core analysis; hominid; human evolution; iron sulfide; magnetic reversal; magnetostratigraphy; Olduvai event; paleolimnology; Pleistocene; remagnetization https://www.scopus.com/inward/record.uri?eid=2-s2.0-85029446255&doi=10.1016%2fj.quageo.2017.08.004&partnerID=40&md5=389c304c9e7701e08c93d03801c735b4 Cited by: 14 Mark J. Sier Cor G. Langereis Guillaume Dupont-Nivet Craig S. Feibel Josephine C.A. Joordens Jeroen H.J.L. Lubbe Catherine C. Beck Daniel Olago Andrew Cohen article Iovine2017 Barium diffusion chronometry applied to sanidine phenocrysts from the trachytic Agnano-Monte Spina eruption (∼4.7 ka) constrains the time between reactivation and eruption of magma batches in the Campi Flegrei caldera. Backscattered electron imaging and quantitative electron microprobe measurements on 50 sanidine phenocrysts from representative pumice samples document core-to-rim compositional zoning. We focus on compositional breaks near the crystal rims that record magma mixing processes just prior to eruption. Diffusion times were modeled at a magmatic temperature of 930 °C using profiles based on quantitative BaO point analyses, X-ray scans, and grayscale swath profiles, yielding times ≤60 years between mixing and eruption. Such short timescales are consistent with volcanological and geochronological data that indicate that at least six eruptions occurred in the Agnano-San Vito area during few centuries before the Agnano-Monte Spina eruption. Thus, the short diffusion timescales are similar to time intervals between eruptions. Therefore, the rejuvenation time of magma residing in a shallow reservoir after influx of a new magma batch that triggered the eruption, and thus pre-eruption warning times, may be as short as years to a few decades at Campi Flegrei caldera. © 2017, Springer-Verlag Berlin Heidelberg. Article 2017 English 02588900 10.1007/s00445-017-1101-4 Bulletin of Volcanology 79 Springer Verlag 2 Campania [Italy]; Campi Flegrei; Italy; Napoli [Campania]; backscatter; caldera; electron probe analysis; geochronology; magmatism; phenocryst; sanidine; timescale; trigger mechanism; volcanic eruption https://www.scopus.com/inward/record.uri?eid=2-s2.0-85010868081&doi=10.1007%2fs00445-017-1101-4&partnerID=40&md5=8e90aa78702502c73f1aaeed7a3bc32c Cited by: 23 Raffaella Silvia Iovine Lorenzo Fedele Fabio Carmine Mazzeo Ilenia Arienzo Andrea Cavallo Gerhard Wörner Giovanni Orsi Lucia Civetta Massimo D’Antonio article Gulley2017964 Synthetic fault-zone trapped wave (FZTW) dispersion curves and amplitude responses for FL (Love) and FR (Rayleigh) type phases are analysed in transversely isotropic 1-D elastic models. We explore the effects of velocity gradients, anisotropy, source location and mechanism. These experiments suggest: (i) A smooth exponentially decaying velocity model produces a significantly different dispersion curve to that of a three-layer model, with the main difference being that Airy phases are not produced. (ii) The FZTW dispersion and amplitude information of a waveguide with transverse-isotropy depends mostly on the Shear wave velocities in the direction parallel with the fault, particularly if the fault zone to country-rock velocity contrast is small. In this low velocity contrast situation, fully isotropic approximations to a transversely isotropic velocity model can be made. (iii) Fault-aligned fractures and/or bedding in the fault zone that cause transverse-isotropy enhance the amplitude and wave-train length of the FR type FZTW. (iv) Moving the source and/or receiver away from the fault zone removes the higher frequencies first, similar to attenuation. (v) In most physically realistic cases, the radial component of the FR type FZTW is significantly smaller in amplitude than the transverse. © The Authors 2017. 2017 English 0956540X 10.1093/gji/ggx200 Geophysical Journal International 210 Oxford University Press 964-978 Department of Mathematics and Dodd-Walls Centre, University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand; School of Environment, University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand; Department of Applied Physics, University of Eastern Finland, P.O. Box 1627, Kuopio, FI-70211, Finland; Department of Physics, University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand; GFZ German Research Center for Geosciences, Telegrafenberg, Potsdam, D-14473, Germany 2 Anisotropy; Dispersion (waves); Faulting; Fracture; Guided electromagnetic wave propagation; Numerical models; Shear waves; Velocity; Water waves, Amplitude information; Fault-zone trapped waves; High strain deformation zones; Higher frequencies; Seismic anisotropy; Shear wave velocity; Transverse isotropy; Transversely isotropic, Shear flow, deformation mechanism; fault zone; faulting; fracture zone; numerical model; seismic anisotropy; seismic attenuation; seismic velocity; strain analysis https://www.scopus.com/inward/record.uri?eid=2-s2.0-85029361547&doi=10.1093%2fgji%2fggx200&partnerID=40&md5=6253640024fe996aab963855dc4ba3c0 cited By 7 A.K. Gulley J.D. Eccles J.P. Kaipio P.E. Malin article DeNatale20172004 Naples and its hinterland in Southern Italy are one of the most urbanized areas in the world under threat from volcanic activity. The region lies within range of three active volcanic centers: Vesuvius, Campi Flegrei, and Ischia. The Campi Flegrei caldera, in particular, has been in unrest for six decades. The unrest followed four centuries of quiescence and has heightened concern about an increased potential for eruption. Innovative modeling and scientific drilling are being used to investigate Campi Flegrei, and the results highlight key directions for better understanding the mechanisms of caldera formation and the roles of magma intrusion and geothermal activity in determining the volcano's behavior. They also provide a framework for evaluating and mitigating the risk from this caldera and other large ones worldwide. © 2017. American Geophysical Union. All Rights Reserved. Note 2017 English 15252027 10.1002/2017GC006972 Geochemistry, Geophysics, Geosystems 18 Blackwell Publishing Ltd 2004 – 2008 5 Volcanoes; Caldera formation; Geothermal activity; Innovative models; Magma intrusion; Scientific drilling; Volcanic activities; Volcanic centers; Volcanic hazards; Hazards https://www.scopus.com/inward/record.uri?eid=2-s2.0-85019073802&doi=10.1002%2f2017GC006972&partnerID=40&md5=f5c68dffd8303bd3d648caa91f167710 Cited by: 13; All Open Access, Green Open Access Giuseppe De Natale Claudia Troise Christopher R. J. Kilburn Renato Somma Roberto Moretti article Reinsch2017 Supercritical geothermal systems are very high-temperature geothermal systems that are located at depths near or below the brittle–ductile transition zone in the crust where the reservoir fluid is assumed to be in the supercritical state, that is for pure water, temperature and pressure are, respectively, in excess of 374 °C and 221 bar. These systems have garnered attention in recent years as a possible type of unconventional geothermal resource due to their very high enthalpy fluids. Supercritical conditions are often found at the roots of volcanic-hosted hydrothermal systems. More than 25 deep wells drilled in geothermal fields such as The Geysers, Salton Sea, and on Hawaii (USA), Kakkonda (Japan), Larderello (Italy), Krafla (Iceland), Los Humeros (Mexico), and Menengai (Kenya) have encountered temperatures in excess of 374 °C, and in some cases have encountered magma. Although fluid entries were documented for some of these wells, it remains an open question if permeability can be maintained at high enthalpy conditions. The IDDP-1 well at Krafla encountered magma, and ended up producing very high enthalpy fluids; however, these fluids were very corrosive and abrasive. Innovative drilling and well completion techniques are therefore needed to deal with the extreme temperatures and aggressive fluid chemistry compositions of these systems. New efforts are underway in Japan (northern Honshu), Italy (Larderello), Iceland (Reykjanes peninsula and Krafla), Mexico (Los Humeros), USA (Newberry), and New Zealand (Taupo Volcanic Zone) to investigate supercritical systems. Here, we review past studies, describe current research efforts, and outline the challenges and potential opportunities that these systems provide for international collaboration to ultimately utilize supercritical geothermal systems as a geothermal energy resource. © 2017, The Author(s). 2017 English 21959706 10.1186/s40517-017-0075-y Geothermal Energy 5 SpringerOpen GFZ German Research Centre for Geosciences, Telegrafenberg, Potsdam, Germany; Energy Geosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States; Fukushima Renewable Energy Institute, AIST, Koriyama, Fukushima, Japan; Istituto Nazionale di Oceanografia e di Geofisica Sperimentale - OGS, Trieste, Italy; Direction des Géoressources, Bureau de Recherches Géologiques et Minières, Orléans, France 1 Energy resources; Enthalpy; Geothermal energy; Geothermal wells; International cooperation; Volcanoes; Well completion, Extreme temperatures; Geothermal resources; Geothermal systems; International collaborations; Supercritical condition; Supercritical systems; Taupo Volcanic Zone; Temperature and pressures, Geothermal fields, chemical composition; enthalpy; geothermal system; high temperature; hydrothermal system; permeability; reservoir; transition zone; well completion, California; Geysers; Hawaii [United States]; Honshu; Iceland; Italy; Iwate; Japan; Kakkonda Geothermal Field; Kenya; Krafla; Larderello; Los Humeros; Menengai Volcano; Mexico [North America]; Nakuru; New Zealand; Newberry Volcano; North Island; Oregon; Pisa [Tuscany]; Puebla [Mexico]; Reykjanes Peninsula; Salton Sea; Taupo Volcanic Zone; Tohoku; Tuscany; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-85029441941&doi=10.1186%2fs40517-017-0075-y&partnerID=40&md5=c4a96742d995c1a8f726d51687e7721b cited By 114 T. Reinsch P. Dobson H. Asanuma E. Huenges F. Poletto B. Sanjuan article conze_utilizing_2017 Article: Utilizing the International Geo Sample Number Concept in Continental Scientific Drilling During ICDP Expedition COSC-1 2017 jan en 1683-1470 10.5334/dsj-2017-002 Data Science Journal 16 1 http://datascience.codata.org/articles/10.5334/dsj-2017-002/ Henning Lorenz Damian Ulbricht Kirsten Elger Thomas Gorgas article Raub2017232 We studied spatiotemporal b-value variations along the North Anatolian Fault Zone (NAFZ) in northwestern Turkey with a focus on the combined 1999 Izmit and Düzce rupture and the eastern Sea of Marmara. We used a local seismicity catalog of the Izmit-Düzce region covering a time span from 2.5 years prior to the Izmit until 14 months after the Düzce mainshock and a four-year hypocenter catalog in the eastern Sea of Marmara. We consistently calculated moment magnitudes to ensure a homogeneous dataset and applied strict quality criteria. This allows studying variations of b-values throughout the region and at different stages of the seismic cycle. With a standard gridding technique b-value maps, depth sections and time series were calculated which reveal a very heterogeneous b-value distribution in the study area. The variety of b-value observations cannot be interpreted unambiguously, given that the b-value most likely depends on a combination of fault-zone characteristics like local stress conditions, heterogeneity of the crust and damage distribution. By presenting a comprehensive set of possible interpretations we point out that a biased discussion of the results towards stress or another individual parameter may lead to erroneous conclusions. Furthermore, the applied data discretization scheme influences the appearance of the final b-value distribution leading to potential misinterpretations. © 2017 Elsevier B.V. 2017 English 00401951 10.1016/j.tecto.2017.05.028 Tectonophysics 712-713 Elsevier B.V. 232-248 Helmholtz Centre Potsdam GFZ German Research Centre for Geosciences, Section 4.2: Geomechanics and Rheology, Telegrafenberg, Potsdam, Germany; Free University Berlin, Dpt. of Earth Sciences, Malteserstrasse 74-100, Berlin, 12249, Germany Geophysics; Physics, B value; B-value analysis; Damage distribution; Data discretization; North Anatolian Fault Zone; Northwestern Turkey; Sea of Marmara; Turkey, Seismology, earthquake catalogue; earthquake hypocenter; earthquake magnitude; earthquake rupture; fault zone; seismicity; spatiotemporal analysis, Anatolia; Sea of Marmara; Turkey https://www.scopus.com/inward/record.uri?eid=2-s2.0-85020018377&doi=10.1016%2fj.tecto.2017.05.028&partnerID=40&md5=19c1df075981262c5667883dc537c16b cited By 8 C. Raub P. Martínez-Garzón G. Kwiatek M. Bohnhoff G. Dresen article Gao2017265 China Cretaceous Continental Scientific Drilling in the Songliao Basin, called SK2 project, has collected 365.32 m of the lower Cretaceous Yingcheng Formation whose age is estimated as Aptian-Albian. The borehole got a highly continuous core section with recovery of 98.47%, which is the most complete and precise geological records up to now for the stratum of continental non-marine Cretaceous in the world. The diameter of core is 214 mm which is among the largest diameter concerning coring engineering. We first described the volcanic-sedimentary succession in centimeter scale and studied the volcanic and sedimentary facies. Considering the sedimentary and volcanic rocks as a whole sequence, we recognized seventeen rock types from drilling core of the Yingcheng Formation. There are nine types of sedimentary rocks, including conglomerate, coarse sandstone, medium sandstone, fine sandstone, siltstone, silty mudstone, mudstone, breccia tuffaceous sandstone, and breccia-bearing tuffaceous sandstone. There are eight types of volcanic rocks including rhyolite, rhyolitic tuff/pyroclastics/agglomerate, rhyolitic welded tuff, crypto-explosive breccia, andesitic tuff, and tuffite. Sedimentary facies is fan delta dominant which includes five sedimentary microfacies of distributary channels, back swamp between delta, subaqueous distributary channels, subaqueous mouth bar and mudstone of still water. Volcanic facies are explosive facies and effusive facies dominant, which include four volcanic subfacies of air-fall, pyroclastic flow deposits, middle and upper flow subfacies of the effusive one. According to detailed description of the Yingcheng sequence, we first recognized three periodic sedimentary and volcanic cycles in the Yingcheng Formation, which have been numbered sedimentary I-volcanic I, sedimentary II-volcanic II, and sedimentary III-volcanic III in ascending order. This is a new discovery concerning the vertical features of of the Yingcheng Formation. The centimeter scale description on the core sections from the SK2 may provide some other useful information for related researches in the future. © 2017, Editorial Office of Earth Science Frontiers. All right reserved. 2017 Chinese 10052321 10.13745/j.esf.2017.01.018 Earth Science Frontiers 24 Science Frontiers editorial department 265-275 College of Earth Sciences, Jilin University, Changchun, 130061, China; Research Center of Palaeontology & Stratigraphy, Jilin University, Changchun, 130026, China; Chongqing University of Science & Technology, Chongqing, 401331, China 1 Boring; Explosives; Rock drilling; Rocks; Sandstone; Sedimentology; Volcanic rocks; Volcanoes, Aptian to Albian; Sedimentary facies; Songliao basin; Volcanic facies; Volcanic-sedimentary succession and cycle; Yingcheng Formation, Sedimentary rocks https://www.scopus.com/inward/record.uri?eid=2-s2.0-85014328929&doi=10.13745%2fj.esf.2017.01.018&partnerID=40&md5=2a8be7d4c70b303e4b7f872b1b3a4ede cited By 5 X. Gao Y. Gao X. Qu H. Li T. Chen P. Wang article Costanzo2017278 Shear wave velocities (VS) are defined in the uppermost 1–2 km of the Campi Flegrei caldera through the non-linear inversion of the group velocity dispersion curves of fundamental-mode Rayleigh waves extracted from ambient noise cross-correlations between two receivers. Noise recordings, three months long, at 12 seismic stations are cross-correlated between all couples of stations. The experiment provided successful results along 54 paths (inter-stations distance), of which 27 sampled a depth > 1 km. VS contour lines are drawn from 0.06 km b.s.l. to 1 km depth b.s.l. and show difference between the offshore (gulf of Pozzuoli and coastline) and the onshore areas. At 0.06 km b.s.l., the gulf of Pozzuoli and the coastline are characterized by VS of 0.3–0.5 km/s and of 0.5–0.7 km/s, respectively. Such velocities are typical of Neapolitan pyroclastic soils and fractured or altered tuffs. The inland shows VS in the range 0.7–0.9 km/s, typical of Neapolitan compact tuffs. Velocities increase with depth and, at 1 km depth b.s.l., velocities lower than 1.5 km/s are still present in the gulf and along the coastline while velocities higher than 1.9 km/s characterize the eastern sector (grossly coincident with the Neapolitan Yellow Tuff caldera rim), the S. Vito plain and the area between Solfatara and SW of Astroni. Such features are much more evident along two cross-sections drawn in the offshore and onshore sectors by integrating our VS models with literature data. Our models join previous noise cross-correlation studies at greater scale at depths of 0.7–0.8 km, hence the picture of the Campi Flegrei caldera is shown up to a depth of 15 km. VS of about 1.7 km/s, corresponding to compression velocities (VP) of about 3 km/s (computed by using the VP/VS ratio resulted in the inversion), are found at depths of 1.1 km, in the centre of the gulf of Pozzuoli, and at a depth of about 0.7 km b.s.l. onshore. An increment of VS velocity (~ 1.9–2.0 km/s) is locally observed onshore which might be attributed to a layer of tuffs and tuffites interbedded with thin lava beds, according to the correlation of VS with stratigraphies in the deep drillings of S. Vito. © 2017 Elsevier B.V. Article 2017 English 03770273 10.1016/j.jvolgeores.2017.09.020 Journal of Volcanology and Geothermal Research 347 Elsevier B.V. 278 – 295 Campania [Italy]; Campi Flegrei; Italy; Napoli [Campania]; Acoustic noise; Group velocity dispersion; Landforms; Rayleigh waves; Shear waves; Velocity; Cross correlations; Fundamental modes; Group velocity dispersion curve; Neapolitan yellow tuffs; Non linear inversion; Pyroclastic soils; Seismic station; Shear wave velocity; ambient noise; caldera; correlation; crustal structure; drilling; Rayleigh wave; S-wave; seismic velocity; tuff; Shear flow https://www.scopus.com/inward/record.uri?eid=2-s2.0-85030460928&doi=10.1016%2fj.jvolgeores.2017.09.020&partnerID=40&md5=2f88ee78f2359c64e0ff21c358fb0744 Cited by: 4 M.R. Costanzo C. Nunziata R. Strollo article Wagner20172033 This study reviews and synthesises existing information generated within the SCOPSCO (Scientific Collaboration on Past Speciation Conditions in Lake Ohrid) deep drilling project. The four main aims of the project are to infer (i) the age and origin of Lake Ohrid (Former Yugoslav Republic of Macedonia/Republic of Albania), (ii) its regional seismotectonic history, (iii) volcanic activity and climate change in the central northern Mediterranean region, and (iv) the influence of major geological events on the evolution of its endemic species. The Ohrid basin formed by transtension during the Miocene, opened during the Pliocene and Pleistocene, and the lake established de novo in the still relatively narrow valley between 1.9 and 1.3 Ma. The lake history is recorded in a 584 m long sediment sequence, which was recovered within the framework of the International Continental Scientific Drilling Program (ICDP) from the central part (DEEP site) of the lake in spring 2013. To date, 54 tephra and cryptotephra horizons have been found in the upper 460 m of this sequence. Tephrochronology and tuning biogeochemical proxy data to orbital parameters revealed that the upper 247.8 m represent the last 637 kyr. The multi-proxy data set covering these 637 kyr indicates long-term variability. Some proxies show a change from generally cooler and wetter to drier and warmer glacial and interglacial periods around 300 ka. Short-term environmental change caused, for example, by tephra deposition or the climatic impact of millennial-scale Dansgaard-Oeschger and Heinrich events are superimposed on the long-term trends. Evolutionary studies on the extant fauna indicate that Lake Ohrid was not a refugial area for regional freshwater animals. This differs from the surrounding catchment, where the mountainous setting with relatively high water availability provided a refuge for temperate and montane trees during the relatively cold and dry glacial periods. Although Lake Ohrid experienced significant environmental change over the last 637 kyr, preliminary molecular data from extant microgastropod species do not indicate significant changes in diversification rate during this period. The reasons for this constant rate remain largely unknown, but a possible lack of environmentally induced extinction events in Lake Ohrid and/or the high resilience of the ecosystems may have played a role. © Author(s) 2017. Review 2017 English 17264170 10.5194/bg-14-2033-2017 Biogeosciences 14 Copernicus GmbH 2033 – 2054 8 Albania; Lake Ohrid; Macedonia [Southern Europe]; Mediterranean Region; Animalia; catchment; climate variation; data set; deep drilling; environmental change; environmental history; extinction; gastropod; glacial-interglacial cycle; Heinrich event; historical record; lake; Miocene; paleoclimate; Pleistocene; Pliocene; project assessment; proxy climate record; seismotectonics; tephra https://www.scopus.com/inward/record.uri?eid=2-s2.0-85018509513&doi=10.5194%2fbg-14-2033-2017&partnerID=40&md5=186cf4992bac12d77115112fa7ccfd0c Cited by: 46; All Open Access, Gold Open Access, Green Open Access Bernd Wagner Thomas Wilke Alexander Francke Christian Albrecht Henrike Baumgarten Adele Bertini Nathalie Combourieu-Nebout Aleksandra Cvetkoska Michele D'Addabbo Timme H. Donders Kirstin Föller Biagio Giaccio Andon Grazhdani Torsten Hauffe Jens Holtvoeth Sebastien Joannin Elena Jovanovska Janna Just Katerina Kouli Andreas Koutsodendris Sebastian Krastel Jack H. Lacey Niklas Leicher Melanie J. Leng Zlatko Levkov Katja Lindhorst Alessia Masi Anna M. Mercuri Sébastien Nomade Norbert Nowaczyk Konstantinos Panagiotopoulos Odile Peyron Jane M. Reed Eleonora Regattieri Laura Sadori Leonardo Sagnotti Bjöern Stelbrink Roberto Sulpizio Slavica Tofilovska Paola Torri Hendrik Vogel Thomas Wagner Friederike Wagner-Cremer George A. Wolff Thomas Wonik Giovanni Zanchetta Xiaosen S. Zhang article Wilke2017789 The position of the cotectic curve separating quartz and feldspar stability fields in the rhyolite system Qz-Ab-Or(-An-H2O) depends on pressure, making it a potential geobarometer applicable to high-silica volcanic products if melt water contents (H2Omelt) are known. Until recently, the applicability of this geobarometer has been limited because pressure effects can be largely obscured by the effects of nearly ubiquitous normative anorthite (An, CaAl2Si2O8) in rhyolitic melts. In this study, we present new phase equilibria data that allow us to constrain the position of thermal minima and quartz-sanidine-plagioclase triple points on the quartz-feldspar cotectic curves at various pressures and melt normative An contents. Data were derived by conducting crystallization experiments to determine phase relations at the following conditions: 200 MPa, 1·4wt%H2Omelt, 3·5wt% An; 200 MPa, 1·3wt % H2Omelt, 7 wt % An; 500 MPa, 3wt % H2Omelt, 3·5wt % An; 500 MPa, 1·4wt % H2Omelt, 3·5wt % An; 500 MPa, 1·3wt%H2Omelt, 7 wt % An. Using this dataset with published phase equilibria results, we present a geobarometer based on the main parameters influencing cotectic compositions in the rhyolitic system: pressure, H2Omelt and melt An content. Our new geobarometer DERP (DEtermining Rhyolite Pressures) is calibrated to calculate pressures of magma storage from cotectic glass compositions with up to 7wt % normative melt An. DERP is calibrated for any H2Omelt in the pressure range 50-500 MPa. Its application is restricted to high-silica rhyolitic systems saturated with respect to quartz and feldspar(s). DERP was tested against various independent methods for estimating rhyolite pressures available in the literature (with an overall error of less than 100 MPa). Comparing pressures estimated with DERP and rhyolite-MELTS, which are based on the same approach, suggests that rhyolite-MELTS underestimates the effect of An. © The Author 2017. Published by Oxford University Press. All rights reserved. 2017 English 00223530 10.1093/petrology/egx034 Journal of Petrology 58 Oxford University Press 789-818 Leibniz Universität Hannover, Institut für Mineralogie, Callinstraße 3, Hannover, 30167, Germany 4 anorthite; crystallization; feldspar; geobarometry; magma; meltwater; petrology; phase equilibrium; quartz; rhyolite https://www.scopus.com/inward/record.uri?eid=2-s2.0-85027138383&doi=10.1093%2fpetrology%2fegx034&partnerID=40&md5=f7933973ad95715250b4c48909558ebb cited By 27 S. Wilke F. Holtz D.A. Neave R. Almeev article Bohnhoff2017332 Discriminating between a creeping and a locked status of active faults is of central relevance to characterize potential rupture scenarios of future earthquakes and the associated seismic hazard for nearby population centres. In this respect, highly similar earthquakes that repeatedly activate the same patch of an active fault portion are an important diagnostic tool to identify and possibly even quantify the amount of fault creep. Here, we present a refined hypocentre catalogue for the Marmara region in northwestern Turkey, where a magnitude M up to 7.4 earthquake is expected in the near future. Based on waveform cross-correlation for selected spatial seismicity clusters, we identify two magnitude M ~ 2.8 repeater pairs. These repeaters were identified as being indicative of fault creep based on the selection criteria applied to the waveforms. They are located below the western part of the Marmara section of the North Anatolian Fault Zone and are the largest reported repeaters for the larger Marmara region. While the eastern portion of the Marmara seismic gap has been identified to be locked, only sparse information on the deformation status has been reported for its western part. Our findings indicate that the western Marmara section deforms aseismically to a substantial extent, which reduces the probability for this region to host a nucleation point for the pending Marmara earthquake. This is of relevance, since a nucleation of the Marmara event in the west and subsequent eastward rupture propagation towards the Istanbul metropolitan region would result in a substantially higher seismic hazard and resulting risk than if the earthquake would nucleate in the east and thus propagate westward away from the population centre Istanbul. © The Authors 2017. 2017 English 0956540X 10.1093/gji/ggx169 Geophysical Journal International 210 Oxford University Press 332-339 GFZ German Research Centre for Geosciences, Section 4.2 'Geomechanics and Rheology', Potsdam, D-14473, Germany; Department of Earth Sciences, Free University Berlin, Berlin, D-12249, Germany; Bestec GmbH, Landau, D-76829, Germany 1 Creep; Faulting; Geophysics; Hazards; Locks (fasteners); Nucleation; Seismic response; Seismology; Transform faults, Earthquake hazard; Metropolitan regions; North Anatolian Fault Zone; Northwestern Turkey; Nucleation points; Rupture propagation; Selection criteria; Waveform cross correlation, Earthquakes, active fault; creep; earthquake catalogue; earthquake magnitude; earthquake rupture; fault zone; seismic hazard; seismicity; transform fault, Marmara [Turkey]; Sea of Marmara; Turkey https://www.scopus.com/inward/record.uri?eid=2-s2.0-85037094140&doi=10.1093%2fgji%2fggx169&partnerID=40&md5=7e0ba7bff71e3d26320c08be28b95a14 cited By 39 M. Bohnhoff C. Wollin D. Domigall L. Küperkoch P. Martínez-Garzón G. Kwiatek P.E. Malin article Vavryčuk20173701 The occurrence and specific properties of earthquake swarms in geothermal areas are usually attributed to a highly fractured rock and/or heterogeneous stress within the rock mass being triggered by magmatic or hydrothermal fluid intrusion. The increase of fluid pressure destabilizes fractures and causes their opening and subsequent shear-tensile rupture. The spreading and evolution of the seismic activity are controlled by fluid flow due to diffusion in a permeable rock (fluid-diffusion model) and/or by redistribution of Coulomb stress (intrusion model). These models, however, are not valid universally. We provide evidence that none of these models is consistent with observations of swarm earthquakes in West Bohemia, Czech Republic. Full seismic moment tensors of microearthquakes in the 2008 swarm in West Bohemia indicate that fracturing at the starting phase of the swarm was not associated with fault openings caused by pressurized fluids but rather with fault compactions. This can physically be explained by a fault-weakening model, when the essential role in the swarm triggering is attributed to degradation of fault strength due to long-lasting chemical and hydrothermal fluid-rock interactions in the focal zone. Since the rock is exposed to circulating hydrothermal, CO2-saturated fluids, the walls of fractures are weakened by dissolving and altering various minerals. The porosity of the fault gauge increases, and the fault weakens. If fault strength lowers to a critical value, the seismicity is triggered. The fractures are compacted during failure, the fault strength recovers, and a new cycle begins. ©2017. American Geophysical Union. All Rights Reserved. Article 2017 English 21699313 10.1002/2017JB013958 Journal of Geophysical Research: Solid Earth 122 Blackwell Publishing Ltd 3701 – 3718 5 Bohemia; Czech Republic; earthquake swarm; erosion; fault; fluid pressure; hydrothermal fluid; intraplate process; microearthquake; moment tensor; seismology https://www.scopus.com/inward/record.uri?eid=2-s2.0-85018379667&doi=10.1002%2f2017JB013958&partnerID=40&md5=bfd4a443930d10ddb23e55ffcf5e319b Cited by: 31; All Open Access, Hybrid Gold Open Access Václav Vavryčuk Pavla Hrubcová article Pistone201747 The Ivrea-Verbano Zone is the most complete, time-integrated crust-upper mantle archive in the world. It is a unique target for assembling data on the deep crust and the Moho transition zone and testing several hypotheses of formation, evolution, and modification of the continental crust through space and time across the Earth. The ICDP workshop Drilling the Ivrea-Verbano zonE (DIVE), held in Baveno, Italy, from 1 to 5 May 2017, focused on the scientific objectives and the technical aspects of drilling and sampling in the Ivrea- Verbano Zone at depth. A total of 47 participants from 9 countries with a wide variety of scientific and/or drilling expertise attended the meeting. Discussion on the proposed targets sharpened the main research lines and led to working groups and the necessary technical details to compile the full drilling proposal. The participants of the workshop concluded that four drilling operations in the Val Sesia and Val d'Ossola crustal sections represent the scientifically most promising solution to achieve the major goals within DIVE to unravel the physico-chemical properties and architecture of the lower continental crust towards the crust-mantle (Moho) transition zone. © Author(s) 2017. Article 2017 English 18168957 10.5194/sd-23-47-2017 Scientific Drilling 23 Copernicus GmbH 47 – 56 Chemical operations; Continental crusts; Drilling operation; Physicochemical property; Scientific objectives; Space and time; Technical aspects; Technical details; Transition zones; Earth (planet) https://www.scopus.com/inward/record.uri?eid=2-s2.0-85036665753&doi=10.5194%2fsd-23-47-2017&partnerID=40&md5=82e3e18bd779c6c8e359f89e926bb71d Cited by: 12; All Open Access, Gold Open Access, Green Open Access Mattia Pistone Othmar Müntener Luca Ziberna György Hetényi Alberto Zanetti article Goswami2017182 Reservoir triggered earthquakes have been occurring in the Koyna area, western India for the past five decades. Triaxial tests carried out on 181 core samples of Archaean granitoids underlying the Deccan Traps provide valuable constraints on rock strength properties in the Koyna seismogenic zone for the first time. The data include measurements on granite gneiss, granite, migmatitic gneiss and mylonitised granite gneiss obtained from boreholes KBH-3, KBH-4A, KBH-5 and KBH-7 located in the western and eastern margins of the seismic zone. Salient results are as follows. (i) Increase of rock strength with increasing confining pressure allow determination of the linearized failure envelopes from which the cohesive strength and angle of internal friction are calculated. (ii) Variable differential stresses at different depths are the manifestations of deformation partitioning in close association of fault zone(s) or localized fracture zones. (iii) Fractures controlled by naturally developed weak planes such as cleavage and fabric directly affect the rock strength properties, but the majority of failure planes developed during triaxial tests is not consistent with the orientations of pre-existing weak planes. The failure planes may, therefore, represent other planes of weakness induced by ongoing seismic activity. (iv) Stress-strain curves confirm that axial deformation is controlled by the varying intensity of pre-existing shear in the granitoids, viz., mylonite, granite gneiss and migmatitic gneiss. (v) Frequent occurrences of low magnitude earthquakes may be attributed to low and variable rock strength of the granitoids, which, in turn, is modified by successive seismic events. © 2017 Elsevier B.V. 2017 English 00401951 10.1016/j.tecto.2017.05.029 Tectonophysics 712-713 Elsevier B.V. 182-192 Borehole Geophysics Research Laboratory, Ministry of Earth Sciences, Karad, 415 114, India; CSIR-National Geophysical Research Institute, Uppal Road, Hyderabad, 500 007, India; CSIR-Central Institute for Mining and Fuel Research, Dhanbad, 826 001, India; Ministry of Earth Sciences, New Delhi, 110 003, India Buildings; Deformation; Granite; Infill drilling; Seismographs; Stress-strain curves, Failure criteria; Granitoids; India; Rock strength; Scientific drilling; Seismic zones, Earthquakes, Archean; basement rock; drilling; failure mechanism; granitoid; rock mechanics; seismic zone; seismicity; strength; stress-strain relationship https://www.scopus.com/inward/record.uri?eid=2-s2.0-85020000079&doi=10.1016%2fj.tecto.2017.05.029&partnerID=40&md5=3a8bd835b17cdc75959292a7f2c8f432 cited By 13 D. Goswami V.V. Akkiraju S. Misra S. Roy S.K. Singh A. Sinha H. Gupta B.K. Bansal S. Nayak article Violante:2017::265 In this study, marine geophysical investigations were utilized to recognize, compare and classify seafloor features related to volcanic activity in the Naples Bay, southern Italy. The dataset includes swath bathymetry, side-scan sonar records, as well as single-channel and multichannel reflection seismics. Ground truth was provided by detailed analysis of gravity cores. By integrating these data, large portions of the seafloor were mapped, providing important information for geohazard assessment. 2017 9780906940570 doi:10.3723/OSIG17.265 Offshore Site Investigation Geotechnics 8th International Conference Proceeding 265-275 https://www.ingentaconnect.com/content/sut/1hzvzd/2017/00000001/00000001/art00014 Crescenzo Violante Marco Sacchi Volkhard Spiess Lena Steinmann inbook waldmann_neugebauer_palchan_hadzhiivanova_taha_brauer_enzel_2017 2017 10.1017/9781316106754.009 Quaternary of the Levant: Environments, Climate Change, and Humans Cambridge University Press Enzel, Yehouda and Bar-Yosef, OferEditors 83–90 Nicolas Waldmann Ina Neugebauer Daniel Palchan Elitsa Hadzhiivanova Nimer Taha Achim Brauer Yehouda Enzel article Hodgson201795 Drilling of intrashelf Miocene clinothems onshore and offshore New Jersey has provided better understanding of their topset and foreset deposits, but the sedimentology and stratigraphy of their bottomset deposits have not been documented in detail. Three coreholes (Sites M27-M29), collected during Integrated Ocean Drilling Program (IODP) Expedition 313, intersect multiple bottomset deposits, and their analysis helps to refine sequence stratigraphic interpretations and process response models for intrashelf clinothems. At Site M29, the most downdip location, chronostratigraphically well-constrained bottomset deposits follow a repeated stratigraphic motif. Coarse-grained glauconitic quartz sand packages abruptly overlie deeply burrowed surfaces. Typically, these packages coarsen then fine upwards and pass upward into bioturbated siltstones. These coarse sand beds are amalgamated and poorly sorted and contain thin-walled shells, benthic foraminifera, and extrabasinal clasts, consistent with an interpretation of debrites. The sedimentology and mounded seismic character of these packages support interpretation as debrite-dominated lobe complexes. Farther updip, at Site M28, the same chronostratigraphic units are amalgamated, with the absence of bioturbated silts pointing to more erosion in proximal locations. Graded sandstones and dune-scale cross-bedding in the younger sequences in Site M28 indicate deposition from turbidity currents and channelization. The sharp base of each package is interpreted as a sequence boundary, with a period of erosion and sediment bypass evidenced by the burrowed surface, and the coarse-grained debritic and turbiditic deposits representing the lowstand systems tract. The overlying fine-grained deposits are interpreted as the combined transgressive and highstand systems tract deposits and contain the deepwater equivalent of the maximum flooding surface. The variety in thickness and grain-size trends in the coarse-grained bottomset packages point to an autogenic control, through compensational stacking of lobes and lobe complexes. However, the large-scale stratigraphic organization of the bottomset deposits and the coarse-grained immature extrabasinal and reworked glauconitic detritus point to external controls, likely a combination of relative sea-level fall and waxing- and-waning cycles of sediment supply. This study demonstrates that large amounts of sediment gravity-flow deposits can be generated in relatively shallow (~100-200 m deep) and low-gradient (~1°-4°) clinothems that prograded across a deep continental shelf. This physiography likely led to the dominance of debris flow deposits due to the short transport distance limiting transformation to low-concentration turbidity currents. © 2017 The Authors. 2017 English 1553040X 10.1130/GES01530.1 Geosphere 14 Geological Society of America 95-114 Stratigraphy Group, School of Earth and Environment, University of Leeds, Leeds, LS2 9JT, United Kingdom; Department of Earth and Planetary Sciences, Rutgers University, Piscataway, NJ 08854, United States; Camborne School of Mines, University of Exeter, Penryn Campus, Penryn, Cornwall, TR10 9FE, United Kingdom; Department of Geosciences, University of Oslo, Oslo, 0371, Norway; Géosciences Rennes, CNRS, Université de Rennes, Campus de Beaulieu, Rennes, 35042, France 1 Erosion; Ocean currents; Offshore drilling; Sea level; Sediment transport; Sedimentology; Sediments; Stratigraphy; Thin walled structures; Turbidity, Benthic foraminifera; Compensational stacking; Highstand systems tract; Integrated ocean drilling programs; Maximum flooding surfaces; Sediment gravity flow; Sequence-stratigraphic interpretation; Stratigraphic organizations, Deposits, chronostratigraphy; debris flow; Miocene; quartz; sediment transport; sedimentology, New Jersey; United States, Foraminifera https://www.scopus.com/inward/record.uri?eid=2-s2.0-85041464062&doi=10.1130%2fGES01530.1&partnerID=40&md5=ab562085ccc23354f8fa105321a5a9e2 cited By 26 D.M. Hodgson J.V. Browning K.G. Miller S.P. Hesselbo M. Poyatos-Moré G.S. Mountain J.-N. Proust conference Burschil2017 A high-resolution P-wave vibroseis reflection survey and PSDM processing are used to image the structure of the Tannwald Basin, a 250 m-deep, distal branch basin of the Rhine Glacier. The basin substratum, the basin base, as well as the basin infill could be identified. The subglacial deposits (e.g. till) can be clearly distinguished from basin fines (e.g. marl, silt and sand). We identified five seismic facies as well as a number of subfacies. Internal features of the basin comprises an allochthonous Molasse block and a system of eskers in section. The interpretation will be used to locate a drill site for the ICDP-project DOVE and provides information for S-wave and multi-component processing. 2017 English 9789462822238 10.3997/2214-4609.201702101 23rd European Meeting of Environmental and Engineering Geophysics European Association of Geoscientists and Engineers, EAGE Liang, Sweden Fertilizers; Seismic waves; Seismology; Shear waves, Drill sites; High resolution; Internal features; Multicomponents; P waves; S-waves; Seismic facies; Vibroseis, Infill drilling https://www.scopus.com/inward/record.uri?eid=2-s2.0-85088410688&doi=10.3997%2f2214-4609.201702101&partnerID=40&md5=d36c6b840f371c0a6cfbfbb257a5e460 cited By 2 T. Burschil H. Buness D. Tanner G. Gabriel C. Krawczyk article Iovine20171 Geochemical and isotopic (87Sr/86Sr and 18O/16O) data have been acquired on whole rock and separated mineral samples from volcanic products of the 1302 AD Arso eruption, Ischia volcanic island (Gulf of Naples, Southern Italy), to investigate magmatic processes. Our results highlight petrographic and isotopic disequilibria between phenocrysts and their host rocks. Similar disequilibria are observed also for more mafic volcanic rocks from Ischia and in the Phlegraean Volcanic District in general. Moreover, 87Sr/86Sr and 18O/16O values suggest mixing between chemically and isotopically distinct batches of magma, and crystals cargo from an earlier magmatic phase. The radiogenic Sr isotope composition suggests that the mantle source was enriched by subduction-derived sediments. Furthermore, magmas extruded during the Arso eruption were affected by crustal contamination as suggested by high oxygen isotope ratios. Assimilation and fractional crystallization modelling of the Sr-O isotope compositions indicates that not more than ~ 7% of granodioritic rocks from the continental crust have been assimilated by a mantle-derived mafic magma. Hence the recent volcanic activity of Ischia has been fed by distinct batches of magma, variably contaminated by continental crust, that mixed during their ascent towards the surface and remobilized phenocrysts left from earlier magmatic phases. © 2016 Elsevier B.V. Article 2017 English 03770273 10.1016/j.jvolgeores.2016.08.008 Journal of Volcanology and Geothermal Research 331 Elsevier B.V. 1 – 15 Campania [Italy]; Ischia; Italy; Napoli [Campania]; Geochemistry; Isotopes; Minerals; Rock products; Volcanic rocks; Volcanoes; Crustal contamination; Ischia island; Magmatic plumbing system; Mingling/mixing; Stable isotopes; crustal contamination; igneous geochemistry; lava; magmatism; mixing; oxygen isotope; point source; source rock; stable isotope; strontium isotope; volcanic eruption; volcanology; Strontium compounds https://www.scopus.com/inward/record.uri?eid=2-s2.0-84995519396&doi=10.1016%2fj.jvolgeores.2016.08.008&partnerID=40&md5=48c8dbda6417476d005825c07e94c056 Cited by: 13 Raffaella Silvia Iovine Fabio Carmine Mazzeo Ilenia Arienzo Massimo D'Antonio Gerhard Wörner Lucia Civetta Zeudia Pastore Giovanni Orsi conference Stefánsson2017512 Conference paper 2017 Transactions - Geothermal Resources Council 41 512 – 522 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85038214846&partnerID=40&md5=d696bf73686675fdca8b0f63a9fb0f13 Cited by: 7 Ari Stefánsson Pór Gíslason Ómar Sigurdsson Gudmundur Ó. Fridleifsson article Cukur2017239 The structural evolution of Lake Van Basin, eastern Turkey, was reconstructed based on seismic reflection profiles through the sedimentary fill as well as from newly acquired multibeam echosounder data. The major sub-basins (Tatvan Basin and Northern Basin) of Lake Van, bound by NE-trending faults with normal components, formed during the past ~600 ka probably due to extensional tectonics resulting from lithospheric thinning and mantle upwelling related to the westward escape of Anatolia. Rapid extension and subsidence during early lake formation led to the opening of the two sub-basins. Two major, still active volcanoes (Nemrut and Süphan) grew close to the lake basins approximately synchronously, their explosive deposits making up >20 % of the drilled upper 220 m of the ca. 550-m-thick sedimentary fill. During basin development, extension and subsidence alternated with compressional periods, particularly between ~340 and 290 ka and sometime before ~14 ka, when normal fault movements reversed and gentle anticlines formed as a result of inversion. The ~14 ka event was accompanied by widespread uplift and erosion along the northeastern margin of the lake, and substantial erosion took place on the crests of the folds. A series of closely spaced eruptions of Süphan volcano occurred synchronously suggesting a causal relationship. Compression is still prevalent inside and around Lake Van as evidenced by recent faults offsetting the lake floor and by recent devastating earthquakes along their onshore continuations. New, high-resolution bathymetry data from Lake Van reveal the morphology of the Northern Ridge and provide strong evidence for ongoing transpression on a dextral strike-slip fault as documented by the occurrence of several pop-up structures along the ridge. © 2016, Springer-Verlag Berlin Heidelberg. 2017 English 14373254 10.1007/s00531-016-1312-5 International Journal of Earth Sciences 106 Springer Verlag 239-253 Petroleum and Marine Research Division, Korea Institute of Geoscience and Mineral Resources (KIGAM), 124 Gwahang-no, Yuseong-gu, Daejeon, 305-350, South Korea; Institute of Geosciences, Kiel University, Otto-Hahn-Platz 1, Kiel, 24118, Germany; Atmosphere and Ocean Research Institute, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa-shi, Chiba, 277-8564, Japan; Department of Water Resources and Drinking Water, Eawag, Swiss Federal Institute of Aquatic Science and Technology, Ueberlandstrasse 133, Duebendorf, 8600, Switzerland; GEOMAR Helmholtz Centre for Ocean Research Kiel, Wischhofstr. 1-3, Kiel, 24148, Germany; Department of Geological Engineering, Van Yüzüncü Yıl University, Van, Turkey; Department of Geological Engineering, Istanbul Technical University, EMCOL, Maslak, Istanbul, 34469, Turkey; Department of Geophysical Engineering, Van Yüzüncü Yıl University, Van, Turkey 1 basin evolution; compression; extensional tectonics; mantle upwelling; seismic data; seismic reflection; spectral resolution; volcanism, Lake Van; Turkey https://www.scopus.com/inward/record.uri?eid=2-s2.0-84960347031&doi=10.1007%2fs00531-016-1312-5&partnerID=40&md5=960a65711079ebc4c8376b869807bbc5 cited By 21 D. Cukur S. Krastel Y. Tomonaga H.-U. Schmincke M. Sumita A.F. Meydan M.N. Çağatay M. Toker S.-P. Kim G.-S. Kong S. Horozal conference Fridleifsson20171095 The Iceland Deep Drilling Project (IDDP) passed a significant milestone in January 2017 when its IDDP-2 well penetrated a supercritical reservoir at a depth of 4.5 km. After only 6 days of heating, the temperature measured at the bottom of the well was ∼426°C, with fluid pressure of 340 bars, with indications of permeability at depth. The IDDP is a project of a consortium of Icelandic energy companies, National Energy Authority of Iceland and Statoil, aimed at greatly increasing the production of usable geothermal energy by drilling deep enough to reach the supercritical zone beneath high-temperature geothermal fields. Modeling indicates that, because of the higher enthalpy of supercritical fluid, and more favorable flow properties, a well producing supercritical water could produce an order of magnitude more usable energy than that produced from conventional high-temperature geothermal wells. The IDDP-2 well is located in the Reykjanes geothermal field which lies near the southern tip of the Reykjanes Peninsula, the landward extension of the Mid-Atlantic Ridge. At Reykjanes, some 34 production and injection wells supply a 100 MWe power plant, producing from a < 300°C reservoir at 1 to 2.5 km depth. It is unique among Icelandic geothermal systems because its reservoir is recharged by seawater, which has a critical point of the 406°C at 298 bars. Drilling the IDDP-2 began by using an existing 2.5 km deep production well, RN-15, that was deepened and cased to 3,000 m depth and then angled towards the main upflow zone of the system for a total slant depth of 4,659 m (∼4.5 km vertical depth). Total circulation losses were encountered below 3 km depth which could not be cured by lost circulation materials or by multiple cement jobs. Accordingly, drilling continued "blind" to total depth, without return of drill cuttings. We attempted 13 core runs below 3 km depth, only 9 of which recovered some core. The cores are basalts and dolerites in a sheeted dike swarm with alteration ranging from lower greenschist facies to lower amphibolite facies, suggesting formation temperatures >450°C, but with low water/rock ratios. A perforated liner was inserted to 4,620 m and the well subsequently logged for temperature, pressure and injectivity. The T-log showed the main permeable zones to be at above 3380 m, with smaller feed zones at 3,820 m, 3,990 m, 4,100, 4,200 m, 4,375 m, and 4,550 m depths. The deeper feed zones accepted ∼5% of the injected water. This year we will attempt to enhance the deeper permeability by massive soft stimulation, and then carry out flow tests to determine the thermodynamic and chemical properties of the fluid produced. Conference paper 2017 English 0934412227 01935933 Transactions - Geothermal Resources Council 41 Geothermal Resources Council 1095 – 1107 HS Orka, Orkubraut 3, Svartsengi, Grindavík, 240, Iceland; Dept. of Earth Sciences, University of California, Riverside, CA 92521, United States Effluent treatment; Geothermal wells; Hydraulic structures; Rhenium compounds; Supercritical fluids; Temperature; Well drilling; Well stimulation, DEEPEGS; Formation temperature; Iceland deep drilling projects; Lost circulation materials; National energy authorities; Reykjanes; Supercritical; Total circulation loss, Geothermal fields https://www.scopus.com/inward/record.uri?eid=2-s2.0-85041042063&partnerID=40&md5=30c093d9908d7a3d2866d6ad08b90e0a Cited by: 16 Gudmundur Ó. Fridleifsson Wilfred A. Elders article Wan201718 Northeast China offers a unique opportunity to perceive Cretaceous stratigraphy and climate of terrestrial settings. The sediments contain variegated clastic and volcanic rocks, diverse terrestrial fossils, and important coal and oil resources. Four Cretaceous biotas of Jehol, Fuxin, Songhuajiang and Jiayin occurred in ascending order. For scientific purpose, a coring program (SK1) provides significant material for Cretaceous research. The SK1 presents a continuous section of Upper Cretaceous non-marine fossils, magnetochron successions and chronostratigraphic events. These events are integrated with marine events by an X/Y graphic plot between the core data and a global database of GSSP and key reference sections. More precisely, age interpolation based on CA-ID-TIMS U-Pb zircon dates and the calibrated cyclostratigraphy places the end of the Cretaceous Normal Superchon at 83.07±0.15 Ma. This date also serves as an estimate for the Santonian-Campanian stage boundary. It also places the K/Pg boundary within the upper part of the Mingshui Formation. The terrestrial and marine life and the analysis of elemental composition, δ13Corg, biomarkers show that lake water salinity changed along with a Coniacian-Santonian marine incursion. High lake-level coincides with the sea transgression during the time. High salinity resulted in the development of periodic anoxic environments of the basin. One of these times of deposition of organic-rich mud correlates with the magnetochron of C34n/C33r and Coniacian-Santonian planktic foraminifera. This marine flooding correlates with OAE 3 and it is possible that the global oceanic anoxic event may have influenced organic carbon burial in the Songliao Basin for this brief period. The evolution of 4 biotas corresponds to the Cretaceous climate change. We tentatively interpret the terrestrial record to reflect the changes in both global climate and regional basin evolution. © 2017, Editorial Office of Earth Science Frontiers. All right reserved. Article 2017 Chinese 10052321 10.13745/j.esf.2017.01.002 Earth Science Frontiers 24 Science Frontiers editorial department 18 – 31 1 Carbon; Coal deposits; Lakes; Lead; Organic carbon; Petroleum deposits; Silicate minerals; Stratigraphy; Volcanic rocks; Cretaceous; Elemental compositions; NE China; Oceanic Anoxic Event; Organic carbon burial; Paleoclimates; Planktic foraminifera; Terrestrial biota; Climate change https://www.scopus.com/inward/record.uri?eid=2-s2.0-85014335623&doi=10.13745%2fj.esf.2017.01.002&partnerID=40&md5=bc3da6e9e4ee55bfde192543516ae3a1 Cited by: 24 Xiaoqiao Wan Huaichun Wu Dangpeng Xi Meiyu Liu Zuohuan Qin inbook torfstein_2017 2017 10.1017/9781316106754.010 Quaternary of the Levant: Environments, Climate Change, and Humans Cambridge University Press Enzel, Yehouda and Bar-Yosef, OferEditors 91–98 Adi Torfstein article deNatale2017443 The recent investigation carried out on the west bound of the Naples metropolitan area and inside the Campi Flegrei caldera as part of the Campi Flegrei Deep Drilling Project provided new insight in order to reconstruct the volcano-tectonic evolution of this extremely populated area. Campi Flegrei represents the highest risk volcanic areas in the world, although its volcano-tectonic structure, eruptive history and eruptive style of the largest eruptions are intensely debatedby scientists since several decades. We present here a summary of stratigraphic and geochronological dating (40Ar/39Ar) allowing to define the age of intra-caldera deposits belonging to the two highest magnitude caldera-forming eruptions (i.e. Campania Ignimbrite, 39÷40 ka, and Neapolitan Yellow Tuff, 14.9 ka) and to evaluate the amount of collapse of the eastern sector of the caldera. These results point out: (i) a reduction of the area affected by caldera collapse, which appears to not include the city of Naples; (ii) a small volume of the infilling caldera deposits, particularly for the CI; and (iii) the need for reassessment of the collapse amounts and mechanisms related to larger eruptions. Our results also imply a revaluation of volcanic risk for the eastern caldera area, including the city of Naples. The results of this study point out that large calderas are characterised by complex collapse mechanisms and dynamics, whose understanding needs more robust constraints, which can be obtained from scientific drilling. © 2017 WIT Press, Article 2017 English 20419031 10.2495/SAFE-V7-N3-443-448 International Journal of Safety and Security Engineering 7 WITPress 443 – 448 3 Campania [Italy]; Campi Flegrei; Italy; Napoli [Campania]; Deposits; Geochronology; Hazards; Stratigraphy; Tectonics; Volcanoes; Caldera-forming eruption; Campi Flegrei; Collapse mechanism; Neapolitan yellow tuffs; Scientific drilling; Tectonic evolution; Tectonic structure; Volcanic hazards; caldera; collapse; dating method; geochronology; hazard; metropolitan area; project assessment; reconstruction; tectonic evolution; tectonic structure; volcanic eruption; Infill drilling https://www.scopus.com/inward/record.uri?eid=2-s2.0-85054032482&doi=10.2495%2fSAFE-V7-N3-443-448&partnerID=40&md5=e5b018b1f16dcc760b83e72b7b2f6899 Cited by: 0; All Open Access, Bronze Open Access Giuseppe Natale Troise Claudia Somma Renato Giovanni Perillo article simon_derivation_2017 2017 sep 0956-540X 10.1093/gji/ggx223 Geophysical Journal International 210 1332--1346 3 https://academic.oup.com/gji/article/210/3/1332/3837696/The-derivation-of-an-anisotropic-velocity-model H. Simon F. Krauß R. Giese P. Hedin C. Juhlin article Gupta2017151 Koyna, located in the Deccan Volcanic Province in western India, is the most significant site of reservoir triggered seismicity (RTS) globally. The largest RTS event of M 6.3 occurred here on December 10,1967. RTS at Koyna has continued. This includes 22 M&gt; 5.0 and thousands of smaller events over the past 50 years. The annual loading and unloading cycles of the Koyna Reservoir and the nearby Warna Reservoir influence RTS. Koyna provides an excellent natural laboratory to comprehend the mechanism of RTS because earthquakes here occur in a small area, mostly at depths of 2-7 km, which are accessible for monitoring. A deep borehole laboratory is therefore planned to study earthquakes in the near-field to understand their genesis, especially in an RTS environment. Initially, several geophysical investigations were carried out to characterize the seismic zone, including 5000 line kilometres of airborne gravity gradiometry and magnetic surveys, high-quality magnetotelluric data from 100 stations, airborne LiDAR surveys over 1064 km2, drilling of 8 boreholes of approximately 1500 m depth and geophysical logging. To improve the earthquake locations a unique network of borehole seismometers was installed in six of these boreholes. These results, along with a pilot borehole drilling plan, are presented here. © 2017 The Author(s). Published by The Geological Society of London. 2017 English 03058719 10.1144/SP445.11 Geological Society Special Publication 445 Geological Society of London 151-188 CSIR, National Geophysical Research Institute, Hyderabad, India; Borehole Geophysical Research Laboratory, Maharashtra, India; National Centre for Earth Science Studies, Thiruvananthapuram, India; Ministry of Earth Sciences, New Delhi, India 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85020047252&doi=10.1144%2fSP445.11&partnerID=40&md5=bfc4c5620ac15fa739e613060629d520 cited By 61 H.K. Gupta K. Arora N.P. Rao S. Roy V.M. Tiwari P.K. Patro H.V.S. Satyanarayana D. Shashidhar C.R. Mahato K.N.S.S.S. Srinivas M. Srihari N. Satyavani Y. Srinu D. Gopinadh H. Raza M. Jana V.V. Akkiraju D. Goswami D. Vyas C.P. Dubey D.C.V. Raju U. Borah K. Raju K.C. Reddy N. Babu B.K. Bansal S. Nayak article Pickarski2017689 A new detailed pollen and oxygen isotope record of the penultimate interglacial-glacial cycle, corresponding to the marine isotope stage (MIS) 7-6, has been generated from the Ahlat Ridge (AR) sediment core at Lake Van, Turkey. The presented Lake Van pollen record (ca. 250.2-128.8 ka) displays the highest temporal resolution in this region with a mean sampling interval of ĝ1/4 540 years. The integration of all available proxies shows three temperate intervals of high effective soil moisture availability. This is evidenced by the predominance of steppe-forested landscapes (oak steppe-forest) similar to the present interglacial vegetation in this sensitive semiarid region between the Black Sea, the Caspian Sea, and the Mediterranean Sea. The wettest and warmest stage, as indicated by highest temperate tree percentages, can be broadly correlated with MIS 7c, while the amplitude of the tree population maximum during the oldest penultimate interglacial (MIS 7e) appears to be reduced due to warm but drier climatic conditions. The detailed comparison of the penultimate interglacial complex (MIS 7) to the last interglacial (Eemian, MIS 5e) and the current interglacial (Holocene, MIS 1) provides a vivid illustration of possible differences in the successive climatic cycles. Intervening periods of treeless vegetation can be correlated with MIS 7d and 7a, in which open landscapes favor local erosion and detrital sedimentation. The predominance of steppe elements (e.g., Artemisia, Chenopodiaceae) during MIS 7d indicates very dry and cold climatic conditions. In contrast, the occurrence of higher temperate tree percentages (mainly deciduous Quercus) throughout MIS 7b points to relatively humid and mild conditions, which is in agreement with other pollen sequences in southern Europe. Despite the general dominance of dry and cold desert-steppe vegetation during the penultimate glacial (broadly equivalent to MIS 6), this period can be divided into two parts: an early stage (ca. 193-157 ka) with higher oscillations in tree percentages and a later stage (ca. 157-131 ka) with lower tree percentages and subdued oscillations. This subdivision of the penultimate glacial is also seen in other pollen records from southern Europe (e.g., MD01-2444 and I-284; Margari et al., 2010; Roucoux et al., 2011). The occurring vegetation pattern is analogous to the division of MIS 3 and MIS 2 during the last glacial in the same sediment sequence. Furthermore, we are able to identify the MIS 6e event (ca. 179-159 ka) as described in marine pollen records, which reveals clear climate variability due to rapid alternation in the vegetation cover. In comparison with long European pollen archives, speleothem isotope records from the Near East, and global climate parameters (e.g., insolation, atmospheric CO2 content), the new high-resolution Lake Van record presents an improved insight into regional vegetation dynamics and climate variability in the eastern Mediterranean region. © Author(s) 2017. 2017 English 18149324 10.5194/cp-13-689-2017 Climate of the Past 13 Copernicus GmbH 689-710 University of Bonn, Steinmann Institute for Geology, Mineralogy and Paleontology, Bonn, Germany 6 climate variation; core analysis; forest-steppe; glacial-interglacial cycle; marine isotope stage; oxygen isotope; paleoecology; paleoenvironment; palynology; proxy climate record; soil moisture; vegetation history, Black Sea; Caspian Sea; Lake Van; Mediterranean Sea; Turkey, Amaranthaceae; Artemisia; Quercus https://www.scopus.com/inward/record.uri?eid=2-s2.0-85020498493&doi=10.5194%2fcp-13-689-2017&partnerID=40&md5=a2b328bc8258274588ba34f297fa16c7 cited By 26 N. Pickarski T. Litt article Rezaee20171727 A new approach is described to allow conditioning to both hard data (HD) and soft data for a patch- and distance-based multiple-point geostatistical simulation. The multinomial logistic regression is used to quantify the link between HD and soft data. The soft data is converted by the logistic regression classifier into as many probability fields as there are categories. The local category proportions are used and compared to the average category probabilities within the patch. The conditioning to HD is obtained using alternative training images and by imposing large relative weights to HD. The conditioning to soft data is obtained by measuring the probability–proportion patch distance. Both 2D and 3D cases are considered. Synthetic cases show that a stationary TI can generate non-stationary realizations reproducing the HD, keeping the texture indicated by the TI and following the trends identified in probability maps obtained from soft data. A real case study, the Mallik methane-hydrate field, shows perfect reproduction of HD while keeping a good reproduction of the TI texture and probability trends. © 2016, Springer-Verlag Berlin Heidelberg. 2017 English 14363240 10.1007/s00477-016-1277-8 Stochastic Environmental Research and Risk Assessment 31 Springer New York LLC 1727-1745 Department of Civil, Geological and Mining, Polytechnique Montréal, C.P. 6079 Succ. Centre-ville, Montreal, QC H3C 3A7, Canada 7 Facsimile; Gas hydrates; Hydration; Regression analysis, Distance functions; Geostatistical simulation; Logistic regression classifier; Methane hydrates; Multinomial logistic regression; Multiple-point geostatistics; Patch based; Soft data, Probability, computer simulation; data set; gas hydrate; geostatistics; methane; probability; regression analysis https://www.scopus.com/inward/record.uri?eid=2-s2.0-84976321931&doi=10.1007%2fs00477-016-1277-8&partnerID=40&md5=6b4589372bfa12ddb1ca0b6772ff6d8f cited By 9 H. Rezaee D. Marcotte article Kallmeyer201761 Drilling is an integral part of subsurface exploration. Because almost all drilling operations require the use of a drill fluid, contamination by infiltration of drill fluid into the recovered core material cannot be avoided. Because it is impossible to maintain sterile conditions during drilling the drill fluid will contain surface microbes and other contaminants. As contamination cannot be avoided, it has to be tracked to identify those parts of the drill core that were not infiltrated by the drill fluid. This is done by the addition of tracer compounds. A great variety of tracers is available, and the choice depends on many factors. This review will first explain the basic principles of drilling before presenting the most common tracers and discussing their strengths and weaknesses. The final part of this review presents a number of key questions that have to be addressed in order to find the right tracer for a particular drilling operation. © 2017 Elsevier Inc. Article 2017 English 00652164 10.1016/bs.aambs.2016.09.003 Advances in Applied Microbiology 98 Academic Press Inc. 61 – 91 Bacteria; Ecosystem; Extraction and Processing Industry; Geologic Sediments; Humans; fluorescent dye; fluorocarbon; microsphere; tracer; Article; drill; ecological procedures; extended core barrel; gravity; hydraulic piston coring; microbial contamination; nonhuman; rotary drilling; tube; wireline coring; bacterium; chemistry; devices; ecosystem; genetics; growth, development and aging; human; isolation and purification; microbiology; mining; procedures; sediment https://www.scopus.com/inward/record.uri?eid=2-s2.0-85005991804&doi=10.1016%2fbs.aambs.2016.09.003&partnerID=40&md5=cf94c86c1e4af01a4407c6a5b4b9b682 Cited by: 10; All Open Access, Green Open Access J. Kallmeyer article Pierre2017537 The New Jersey continental shelf extends 150 km off the shoreline. During IODP Expedition 313, siliciclastic deposits of late Eocene to late Pleistocene age were drilled down to 631, 669 and 755 m below seafloor at sites 27A, 28A and 29A respectively in very shallow waters (33.5 to 36 m depth). Pore water salinities display multilayered brackish-salty-brine units 10 to 170 m thick, where low-salinity water is preferentially stored in fine-grained sediments. The sharp boundaries of these buried aquifers are often marked by cemented layers a few centimetres thick. The mineralogy and scanning electron microscope observations of these layers show two phases of cementation by authigenic minerals: (1) the early carbonate cement is frequently associated with pyrite, and (2) the late silicate cement infills the residual porosity. The isotopic compositions of the carbonate cements vary widely: −2.4 &lt; δ18O ‰ VPDB &lt; +2.8; −15.1 &lt; δ13C ‰ VPDB &lt; +15.6. The δ18O values indicate that the carbonate cements precipitated with pore waters comprising variable mixtures of seawater and 18O-depleted fresh water originating from submarine groundwater discharge. The δ13C values of the carbonate cements are related to organic matter diagenesis, providing 13C-depleted dissolved inorganic carbon during bacterial sulphate reduction and anaerobic oxidation of methane, and 13C-rich dissolved inorganic carbon during methanogenesis. The diagenetic cementation processes included chemical weathering of reactive silicate minerals by the CO2-rich pore waters issued from organic matter diagenesis that released bicarbonate, cations and dissolved silica, which were further precipitated as carbonate and silicate cements. The estimated range of temperature (18±4 °C) during carbonate precipitation is consistent with carbonate cementation at moderate burial depths; however, silicate cementation occurred later during diagenesis at deeper burial depths. © 2017, Springer-Verlag Berlin Heidelberg. 2017 English 02760460 10.1007/s00367-017-0506-6 Geo-Marine Letters 37 Springer Verlag 537-547 UPMC-Sorbonne Universités, LOCEAN, 4 place Jussieu, Paris Cedex 05, 75252, France; MNHN-Sorbonne Universités, CR2P, 57 rue Cuvier, Paris, 75005, France; UPMC-Sorbonne Universités, ISTEP, 4 place Jussieu, Paris Cedex 05, 75252, France; Geosciences Montpellier, Université Montpellier, Montpellier Cedex 5, 34095, France 6 Aquifers; Biogeochemistry; Biological materials; Carbon; Carbon dioxide; Carbonation; Cementing (shafts); Discharge (fluid mechanics); Dissolution; Groundwater; Groundwater resources; Hydrogeology; Minerals; Organic compounds; Organic minerals; Scanning electron microscopy; Sedimentology; Silicate minerals; Silicates; Submarines; Water; Weathering, Anaerobic oxidation of methanes; Bacterial sulphate reductions; Carbonate precipitation; Dissolved inorganic carbon; Fine-grained sediment; Pore water salinities; Siliciclastic sediments; Submarine groundwater discharge, Cements, carbonate sediment; cementation; chemical weathering; continental shelf; discharge; groundwater; Ocean Drilling Program; organic matter; silicate mineral; siliciclastic deposit; underwater environment, Atlantic Ocean; New Jersey Shelf, Bacteria (microorganisms) https://www.scopus.com/inward/record.uri?eid=2-s2.0-85017156984&doi=10.1007%2fs00367-017-0506-6&partnerID=40&md5=bbd8001cb936f14dba670691b81563d9 cited By 3 C. Pierre M.-M. Blanc-Valleron O. Boudouma J. Lofi article Kremer2017117 Article 2017 10.1016/j.precamres.2017.04.023 Precambrian Research 295 117 – 129 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85018649596&doi=10.1016%2fj.precamres.2017.04.023&partnerID=40&md5=cb3e2bf17710234c0022174a648e3ba8 Cited by: 21 Barbara Kremer Józef Kaźmierczak article Kring20174 The Chicxulub crater is the only wellpreserved peak-ring crater on Earth and linked, famously, to the K-T or K-Pg mass extinction event. For the first time, geologists have drilled into the peak ring of that crater in the International Ocean Discovery Program and International Continental Scientific Drilling Program (IODP-ICDP) Expedition 364. The Chicxulub impact event, the environmental calamity it produced, and the paleobiological consequences are among the most captivating topics being discussed in the geologic community. Here we focus attention on the geological processes that shaped the ~200-km-wide impact crater responsible for that discussion and the expedition's first year results. Copyright 2017, The Geological Society of America. 2017 10.1130/GSATG352A.1 GSA Today 27 4-8 Lunar and Planetary Institute, Houston, TX 77058, United States; Analytical, Environmental and Geo-Chemistry, Vrije Universiteit Brussel, Pleinlaan 2, Brussels, 1050, Belgium; Institute for Geophysics, Dept. of Geological Sciences, Jackson School of Geosciences, University of Texas at Austin, Austin, TX 78758, United States; Dept. of Earth Science and Engineering, Imperial College LondonSW7 2AZ, United Kingdom; United States; France; United Kingdom; Australia; Austria; Germany; Japan; Mexico; Netherlands; China 10 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85032494931&doi=10.1130%2fGSATG352A.1&partnerID=40&md5=c2c21bc59483ee15f51e32b66ed72013 cited By 19 D.A. Kring P. Claeys S.P.S. Gulick J.V. Morgan G.S. Collins T. Bralower E. Chenot G. Christeson C. Cockell M.J.L. Coolen L. Ferrière C. Gebhardt K. Goto H. Jones J. Lofi C. Lowery C. Mellett R. Ocampo-Torres L. Pérez-Cruz A. Pickersgill M. Poelchau A. Rae C. Rasmussen M. Rebolledo-Vieyra U. Riller H. Sato J. Smit S. Tikoo N. Tomioka J. Urrutia-Fucugauchi M. Whalen A. Wittmann L. Xiao K.E. Yamaguchi W. Zylberman IODP-ICDP Expedition 364 Science Party article mougel2017chromium 2017 Earth and Planetary Science Letters 460 Elsevier 105--111 Bérengère Mougel Frédéric Moynier Christa Göpel inbook stein_lazar_torfstein_goldstein_2017 2017 10.1017/9781316106754.008 Quaternary of the Levant: Environments, Climate Change, and Humans Cambridge University Press Enzel, Yehouda and Bar-Yosef, OferEditors 75–82 Mordechai Stein Boaz Lazar Adi Torfstein Steven L. Goldstein article Jouve201733 Article 2017 10.1016/j.palaeo.2017.02.020 Palaeogeography, Palaeoclimatology, Palaeoecology 472 33 – 50 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85013018756&doi=10.1016%2fj.palaeo.2017.02.020&partnerID=40&md5=d5b39e238e519b8563fc6cb03b923d0e Cited by: 4; All Open Access, Green Open Access Guillaume Jouve Agathe Lisé-Pronovost Pierre Francus Arnaud S. De Coninck article Kallmeyer201761 Drilling is an integral part of subsurface exploration. Because almost all drilling operations require the use of a drill fluid, contamination by infiltration of drill fluid into the recovered core material cannot be avoided. Because it is impossible to maintain sterile conditions during drilling the drill fluid will contain surface microbes and other contaminants. As contamination cannot be avoided, it has to be tracked to identify those parts of the drill core that were not infiltrated by the drill fluid. This is done by the addition of tracer compounds. A great variety of tracers is available, and the choice depends on many factors. This review will first explain the basic principles of drilling before presenting the most common tracers and discussing their strengths and weaknesses. The final part of this review presents a number of key questions that have to be addressed in order to find the right tracer for a particular drilling operation. © 2017 Elsevier Inc. 2017 English 00652164 10.1016/bs.aambs.2016.09.003 Advances in Applied Microbiology 98 Academic Press Inc. 61-91 GFZ German Research Centre for Geosciences, Potsdam, Germany fluorescent dye; fluorocarbon; microsphere; tracer, Article; drill; ecological procedures; extended core barrel; gravity; hydraulic piston coring; microbial contamination; nonhuman; rotary drilling; tube; wireline coring; bacterium; chemistry; devices; ecosystem; genetics; growth, development and aging; human; isolation and purification; microbiology; mining; procedures; sediment, Bacteria; Ecosystem; Extraction and Processing Industry; Geologic Sediments; Humans https://www.scopus.com/inward/record.uri?eid=2-s2.0-85005991804&doi=10.1016%2fbs.aambs.2016.09.003&partnerID=40&md5=cf94c86c1e4af01a4407c6a5b4b9b682 cited By 10 J. Kallmeyer article Moyer20171333 Article 2017 10.1785/0220160218 Seismological Research Letters 88 1333 – 1338 5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85028305769&doi=10.1785%2f0220160218&partnerID=40&md5=19f0e04ef33a5265b0a229b4219107d1 Cited by: 3 Pamela A. Moyer Margaret S. Boettcher William L. Ellsworth Hiroshi Ogasawara Artur Cichowicz Denver Birch Gerhard Van Aswegen article 2017 10.19509/j.cnki.dzkq.2017.0437 Geological Science and Technology Information 36 271-276 4 N. Li C. Zou C. Peng J. Zhao Y. Niu article Chamberlain201763 The Alpine Fault is inferred on paleoseismological grounds to produce magnitude 8 earthquakes approximately every 330 yrs and to have last ruptured almost 300 yrs ago in 1717 AD. Despite approximately 90% of its typical interseismic period having elapsed since the last major earthquake, the Alpine Fault exhibits little present-day microseismicity and no geodetic evidence for shallow creep. Determining the mechanical state of the fault ahead of a future earthquake is a key objective of several studies, including the Deep Fault Drilling Project (DFDP). Here we use a network of borehole seismometers installed in conjunction with DFDP to detect and characterise low-magnitude seismicity adjacent to the central section of the Alpine Fault. We employ matched-filter detection techniques, automated cross-correlation phase picking, and singular value decomposition-derived magnitude estimation to construct a high-precision catalogue of 283 earthquakes within 5 km of the fault trace in an otherwise seismically quiet zone. The newly recognised seismicity occurs in non-repeating, spatially and temporally limited sequences, similar to sequences previously documented using standard methods but at significantly lower magnitudes of ML&lt;1.8. These earthquakes are not clustered on a single distinctive structure, and we infer that they are distributed throughout a highly fractured zone surrounding the Alpine Fault. Focal mechanisms computed for 13 earthquakes using manual polarity picks exhibit predominantly strike-slip faulting, consistent with focal mechanisms observed further from the fault. We conclude that the Alpine Fault is locked and accumulating strain throughout the seismogenic zone at this location. © 2016 Elsevier B.V. 2017 English 0012821X 10.1016/j.epsl.2016.09.061 Earth and Planetary Science Letters 457 Elsevier B.V. 63-72 School of Geography, Environment and Earth Sciences, Victoria University of Wellington, PO Box 600, Wellington, 6012, New Zealand; International Earth Sciences IESE Ltd, PO Box 68795, Newton, Auckland, 1145, New Zealand Fault detection; Locks (fasteners); Matched filters; Seismic waves; Seismographs; Signal detection; Singular value decomposition; Strike-slip faults, Alpine Faults; Earthquake swarms; Inter-seismic periods; Magnitude estimation; Matched filter detections; Microseismicity; South Westland , New Zealand; Strike slip faulting, Earthquakes, detection method; earthquake magnitude; earthquake swarm; fault zone; focal mechanism; seismicity; singular value decomposition, Alpine Fault Zone; New Zealand; South Island https://www.scopus.com/inward/record.uri?eid=2-s2.0-84995780851&doi=10.1016%2fj.epsl.2016.09.061&partnerID=40&md5=b550635ef061afb311a7a03922b56802 cited By 17 C.J. Chamberlain C.M. Boese J. Townend article Dergachev2017877 An inhomogeneous time series of measurements of the percentage content of biogenic silica in the samples of joint cores BDP-96-1 and BDP-96-2 from the bottom of Lake Baikal drilled at a depth of 321 m under water has been analyzed. The composite depth of cores is 77 m, which covers the Pleistocene Epoch to 1.8 Ma. The time series was reduced to a regular form with a time step of 1 kyr, which allowed 16 distinct quasi-periodic components with periods from 19 to 251 kyr to be revealed in this series at a significance level of their amplitudes exceeding 4σ. For this, the combined spectral periodogram (a modification of the spectral analysis method) was used. Some of the revealed quasi-harmonics are related to the characteristic cyclical oscillations of the Earth’s orbital parameters. Special focus was payed to the temporal change in the parameters of the revealed quasi-harmonic components over the Pleistocene Epoch, which was studied by constructing the spectral density of the analyzed data in the running window of 201 and 701 kyr. © 2017, Pleiades Publishing, Ltd. Article 2017 English 00167932 10.1134/S0016793217070052 Geomagnetism and Aeronomy 57 Maik Nauka-Interperiodica Publishing 877 – 885 7 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85042514067&doi=10.1134%2fS0016793217070052&partnerID=40&md5=945f766e2412ac49e03468d1bc12b82d Cited by: 0 V.A. Dergachev P.B. Dmitriev inbook torfstein_enzel_2017 2017 10.1017/9781316106754.013 Quaternary of the Levant: Environments, Climate Change, and Humans Cambridge University Press Enzel, Yehouda and Bar-Yosef, OferEditors 115–126 Adi Torfstein Yehouda Enzel article Lozano-García2017299 This paper presents a short description of the coring operations undertaken to recover the full lacustrine sedimentary sequence from Chalco. Geophysical techniques were used to determine the distribution and thickness of the sediments in order to select the drilling site. Resonance frequencies determined from H/V spectral ratios were used to determine an area where lake sediments reached 300 m thickness. Electromagnetic survey showed two changes in electric resistivity which were related to changes in sediment composition, the first from 100 to 120 m, related to an increase in volcanoclastic sediments and the second from 330 to 400 m related to the presence of a basaltic flows. Three wells were drilled with continuous recovery, reaching depths of 420 m in well A, 310 in B and 520 in C. Samples for geomicrobiological and metagenomics studies were collected during drilling operations. A total of 1152 m of core sediments were recovered reaching a maximum depth of 520 m. Recovery percentages were between 88 and 92 % in the three wells. Magnetic susceptibility analyses in the three sequences show that the first 260 m are mostly lake sediments, between 260 and 300 m sediments are coarser and below 300 m they are mostly volcaniclastic. Analysis of the sedimentary sequence of Lake Chalco that covers the last ~300000 years will allow documenting and extending the knowledge of climate variability in area, the paleoenvironmental history, basin closure history, lacustrian system development and volcanic activity recurrence. Studies of the physical properties of this sequence will be important for seismic propagation and basin structure modeling, and also will improve modeling of the subsidence process that this region experiences. 2017 English; Spanish 14053322 10.18268/BSGM2017v69n2a2 Boletin de la Sociedad Geologica Mexicana 69 Instituto de Geología, Universidad Nacional Autónoma de México 299-311 Instituto de Geología, Universidad Nacional Autónoma de México, Ciudad Universitaria, Ciudad de México, C.P. 04510, Mexico; University of Minnesota, Large Lakes Observatory, Duluth, MN 55812, United States; Instituto de Geofísica, Universidad Nacional Autónoma de México, Ciudad Universitaria, Ciudad de México, C.P. 04510, Mexico; University of Pittsburgh, Department of Geology and Environmental SciencePA 15260, United States; University of New Mexico, Department of Earth and Planetary SciencesNM 87131, United States; Institute of Geosystem and Bioindication, Technical University of Braunschweig, Braunschweig, 38106, Germany; Instituto Pirenaíco de Ecología, Avda. Montaña 1005, Zaragoza, 50059, Spain; CSDCO/LacCore, University of Minnesota MinneapolisMN 55455, United States; Departmento de Geofísica, Instituto Steinmann, Universidad de Bonn, Meckenheimer Allee 176, Bonn, Alemania, 53115, Germany; Grupo de Geofísica, Departmento de Gedesia y Geoinformation, Viena Universidad de Tecnología, Gußhausstr. 25-29, Viena, 1040, Austria; Leibniz-Institut für Angewandte Geophysik LIAG, Hannover, Germany; University of Birmingham, School of Geography, Earth and Environmental Sciences, United Kingdom 2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85028953927&doi=10.18268%2fBSGM2017v69n2a2&partnerID=40&md5=1c258cef699f14fb8251fe9d04698bcb cited By 19 S. Lozano-García E.T. Brown B. Ortega M. Caballero J. Werne P.J. Fawcett A. Schwalb B.L. Valero-Garcés D. Schnurrenberger R. O'Grady M. Stockhecke B. Steinman E. Cabral-Cano C. Caballero S. Sosa-Nájera A.M. Soler L. Pérez A. Noren A. Myrbo M. Bücker N. Wattrus A. Arciniega T. Wonik S. Watt D. Kumar C. Acosta I. Martínez R. Cossio T. Ferland F. Vergara-Huerta article Branscombe201741 Note 2017 English 00963941 10.1029/2017eo067075 Eos (United States) 98 American Geophysical Union 41 4 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85029424437&doi=10.1029%2f2017eo067075&partnerID=40&md5=0b1bf70beeff649bd1ccab55c3aa2d43 Cited by: 0; All Open Access, Gold Open Access Alexandra Branscombe article Yoshino2017352 We recovered a Campanian–Maastrichtian palynological record in transitional succession from the Sifangtai to Mingshui formations of the Songke Core-1 (North) (SK1 (N)) in the Songliao Basin, Northeast China. These formations are composed mainly of various colored mudstones and sandstones. The lithofacies variation suggests that the paleoenvironment changed from flood plain to lake. Most of the palynomorph assemblages are dominated by gymnosperm pollen, followed by spore of pteridophyte, and angiosperm pollen. On the basis of the first occurrences of marker genera within the succession, we identified four palynomorph interval zones (in ascending order): the Jianghanpollis, Chenopodipollis, Toroisporis, and Betulaceoipollenites interval zones. The first two interval zones are found from flood plain and levee deposits. The third one is recognized from lake basin plain–lake basin slope deposits. The last one is found in delta deposits within lakeshore. We consider that environmental changes are the major factors that formed component of Campanian–Maastrichtian assemblage in the Songliao Basin. In addition, the Jianghanpollis and Chenopodipollis interval zones are assigned to the Campanian, whereas the Toroisporis and Betulaceoipollenites interval zones date as the Maastrichtian. Thus, the Chenopodipollis/Toroisporis zonal boundary approximates the C/M boundary. Triprojectate pollen such as Aquilapollenites is regarded as marker taxa in the study section and other areas within the Aquilapollenites Province during the Campanian–Maastrichtian. However, Wodehouseia spp. have yet been confirmed within the study section, although this genus has appeared in Campanian–Maastrichtian deposits in other areas. This is one of the important clues to understand regional difference of local flora in these ages. © 2016 Elsevier B.V. and Nanjing Institute of Geology and Palaeontology, CAS 2017 English 1871174X 10.1016/j.palwor.2016.10.001 Palaeoworld 26 Elsevier B.V. 352-368 State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing, 100083, China; Graduate School of Science and Technology, Niigata University, Niigata, 950-2181, Japan; Department of Geological Engineering, Qinghai University, Xining, 810016, China; Department of Geology, Faculty of Science, Niigata University, Niigata, 950-2181, Japan 2 angiosperm; biostratigraphy; Campanian; core analysis; flora; gymnosperm; lacustrine deposit; levee; lithofacies; lithostratigraphy; Maastrichtian; mudstone; paleoenvironment; palynology; palynomorph; pollen; pteridophyte; sandstone; terrestrial deposit, China; Songliao Basin, Gymnospermae; Magnoliophyta; Pteridophyta https://www.scopus.com/inward/record.uri?eid=2-s2.0-85006240155&doi=10.1016%2fj.palwor.2016.10.001&partnerID=40&md5=12a84f4c57720d2a46c86624f3edfc9a cited By 8 K. Yoshino X.-Q. Wan D.-P. Xi W. Li A. Matsuoka article Randlett2017571 Lipid biomarkers were analyzed in Lake Van sediments covering the last 600 ka, with a focus on the period between 110 and 10 ka, when a broad maximum in pore water salinity as a relict from the past suggests dry conditions. The occurrence and distribution of biomarkers indicative for terrestrial plants (long-chain n-alkane C29), haptophyte algae (methyl alkenones C37) and halophilic archaea (archaeol) all point toward a dry climate in Lake Van region during this time interval. The hydrogen isotopic composition of C29 n-alkanes (δDC29) and C37 alkenones (δDC37) is enriched between MIS 4 and MIS 2, which is interpreted as a decrease in the regional ratio of precipitation to evaporation. Similarly, the low abundance of the acyclic glycerol dialkyl glycerol tetraether GDGT-0 relative to archaeol, quantified by the Archaeol and Caldarchaeol Ecometric (ACE) is assumed to reflect the presence of halophilic euryarchaeota adapted to high salinity water. The climate around Lake Van appears in phase with the Yammouneh basin 800 km southwest and Lake Urmia 250 km southeast of Lake Van over the last two glacial periods. The results highlight the potential of combining ACE, δDC29, and δDC37 for reconstructing salinity changes and regional precipitation to evaporation ratio from lake sediments. © 2017. American Geophysical Union. All Rights Reserved. 2017 English 15252027 10.1002/2016GC006621 Geochemistry, Geophysics, Geosystems 18 Blackwell Publishing Ltd 571-583 Eawag, Swiss Federal Institute of Aquatic Science and Technology, Department of Surface Waters – Research and Management, Kastanienbaum, Switzerland; ETH Zurich, Institute of Biogeochemistry and Pollutant Dynamics, Zurich, Switzerland; Chair in Petroleum Geology, Montanuniversität, Leoben, Austria; NIOZ Royal Netherlands Institute for Sea Research and Utrecht University, Department of Marine Microbiology and Biogeochemistry, 't Horntje (Texel), Netherlands; Department of Earth Sciences, Utrecht University, Utrecht, Netherlands; Steinmann Institute of Geology, Mineralogy and Palaeontology, University of Bonn, Bonn, Germany; Ruhr-Universität Bochum, Institut für Sediment- und Isotopengeologie, Bochum, Germany; Eawag, Department of Surface Water - Research and Management, Dübendorf, Switzerland; Large Lakes Observatory, University of Minnesota Duluth, Duluth, MN, United States 2 Evaporation; Glycerol; Isotopes; Lakes; Paraffins; Sediments, ACE index; Halophilic archaea; Hydrogen isotope; Hydrogen isotopic composition; Lake vans; Long chain n-alkanes; Occurrence and distribution; Pore water salinities, Biomarkers, biomarker; hydrogen isotope; isotopic composition; lacustrine deposit; lipid; paleoclimate; porewater; salinity, Anatolia; Lake Van; Turkey, algae; Euryarchaeota https://www.scopus.com/inward/record.uri?eid=2-s2.0-85013301833&doi=10.1002%2f2016GC006621&partnerID=40&md5=8082cd340625cc67a378bbc9c8131c21 cited By 19 M.-E. Randlett A. Bechtel M.T.J. Meer F. Peterse T. Litt N. Pickarski O. Kwiecien M. Stockhecke B. Wehrli C.J. Schubert article Kind201719 We used S-receiver functions (i.e. S-to-P converted signals) to study seismic discontinuities in the upper mantle between the Moho and the 410 km discontinuity beneath central Europe. This was done by using c. 49,000 S-receiver functions from c. 700 permanent and temporary broadband stations made available by the open EIDA Archives. Below Phanerozoic Europe we observed expected discontinuities like the Moho, the lithosphere-asthenosphere boundary (LAB), the Lehmann discontinuity and the 410 km discontinuity with an additional overlying low velocity zone. Below the East European Craton (EEC), we observed the Mid-Lithospheric Discontinuity (MLD) at c. 100 km depth as well as the controversial cratonic LAB at c. 200 km depth. At the boundary of the EEC but still below the Phanerozoic surface, we observed downward velocity reductions below the LAB in the following regions: the North German-Polish Plain at about 200 km depth; the Bohemian Massive, north-west dipping from 200 to 300 km depth; the Pannonian Basin, north-east dipping from 150 to 200 km depth underneath the western Carpathians and the EEC. We named this newly observed structure Sub-Lithospheric Discontinuity (SLD). At the northern edge of the Bohemian Massive, we see a sharp vertical step of about 100 km between the SLD below the Bohemian Massive and the North German-Polish Plain. This step follows the surface trace of the Rheic Suture between the continental Saxo-Thuringian and Rheno-Herzynian zones of the Variscan orogen. A preliminary interpretation of these features is that a prong of the cratonic mantle lithosphere penetrated the Phanerozoic asthenosphere during the continental collision at the western and south-western edges of the EEC. © 2017 Elsevier B.V. Article 2017 English 00401951 10.1016/j.tecto.2017.02.002 Tectonophysics 700-701 Elsevier B.V. 19 – 31 Bohemian Massif; East European Craton; Pannonian Basin; Laboratories; Bohemian massifs; East-European craton; Lithosphere-asthenosphere boundary; Lithospheric; Pannonian basin; S-receiver functions; asthenosphere; craton; discontinuity; lithosphere; Moho; seismograph; upper mantle; Structural geology https://www.scopus.com/inward/record.uri?eid=2-s2.0-85013127722&doi=10.1016%2fj.tecto.2017.02.002&partnerID=40&md5=d96198b0cacdf922cdd3f2ed5a420b9c Cited by: 17 Rainer Kind Mark R. Handy Xiaohui Yuan Thomas Meier Horst Kämpf Riaz Soomro article Gulley2017919 We develop a computationally efficient approach to compute the waveforms and the dispersion curves for fault-zone trapped waves guided by arbitrary transversely isotropic across-fault velocity models. The approach is based on a Green's function type representation for FL and FR type fault-zone trapped waves. The model can be used for simulation of the waveforms generated by both infinite line sources (2-D) and point sources (3-D). The numerical scheme is based on a high order finite element approximation and, to increase computational efficiency, we make use of absorbing boundary conditions and mass lumping of finite element matrices. © The Authors 2017. 2017 English 0956540X 10.1093/gji/ggx199 Geophysical Journal International 210 Oxford University Press 919-930 Department of Mathematics and Dodd-Walls Centre, University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand; Department of Applied Physics, University of Eastern Finland, P.O. Box 1627, Kuopio, FI-70211, Finland; School of Environment, University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand; Department of Physics, University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand; GFZ German Research Center for Geosciences, Telegrafenberg, Potsdam, D-14473, Germany 2 Finite element method; Guided electromagnetic wave propagation; Water waves, Absorbing boundary condition; Computationally efficient; Fault-zone trapped waves; Finite element matrices; High-order finite elements; Numerical approximations and analysis; Numerical solution; Seismic anisotropy, Computational efficiency, boundary condition; fault zone; finite element method; Green function; numerical model; seismic anisotropy; transverse isotropy; trapped wave; wave generation; waveform analysis https://www.scopus.com/inward/record.uri?eid=2-s2.0-85037127289&doi=10.1093%2fgji%2fggx199&partnerID=40&md5=f58d629352b82c5b86992065fe167ba1 cited By 7 A.K. Gulley J.P. Kaipio J.D. Eccles P.E. Malin article Guo2017935 The Deep Fault Drilling Project (DFDP) on the central Alpine Fault, South Island, New Zealand, has motivated a broad range of geophysical and geological studies intended to characterize the fault system in the locality of the drill site at various scales. In order to better understand the structural features of the central Alpine Fault, we have developed 3-D P- and S-wave velocity (VP and VS) models of the region by double-difference tomography using data sets from multiple seismic networks. In previous work, the quality of the S-wave model has been poor due to the small number of available S-wave picks. We have utilized a new high-accuracy automatic S-wave picker to increase the number of usable S-wave arrivals by more than a factor of two, thereby substantially improving the VS model. Compared to previous studies, our new higher-resolution VP model based on more observations shows a clear VP contrast (higher VP on the southeast hanging wall side) at depths of 5-10 km near the DFDP drill sites. With our better resolved VS model, in the same region, we detect a sharply defined high VS body (VS > 3.7 km s-1) within the hanging wall. Our earthquake relocations reveal the presence of clusters within and around low-velocity zones in the hanging wall southeast of the Alpine Fault. Together with the improved earthquake locations, the P- and S-wave tomography results reveal the Alpine Fault to be marked by a velocity contrast throughout most of the study region. The fault dips southeastwards at about 50° from 5 to 15 km depth, as inferred from the velocity structure, seismicity and observations of fault zone guided waves. © 2017 The Authors 2017. Published by Oxford University Press on behalf of The Royal Astronomical Society. 2017 English 0956540X 10.1093/gji/ggx059 Geophysical Journal International 209 Oxford University Press 935-947 Department of Geoscience, University of Wisconsin-Madison, 1215W Dayton St, Madison, WI 53706, United States; Earth and Environmental Sciences, Rensselaer Polytechnic Institute, 110 Eighth Street, Troy, NY 12180, United States; School of Geography Environment, and Earth Sciences, Victoria University of Wellington, P.O. Box 600, Wellington, 6140, New Zealand; GNS Science, P.O. Box 30-368, Lower Hutt, 5040, New Zealand; School of Environment, University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand 2 Acoustic wave velocity; Drills; Earthquakes; Faulting; Guided electromagnetic wave propagation; Infill drilling; Tomography, Double-difference tomography; Earthquake location; Earthquake relocation; P- and S-wave velocities; South Island , New Zealand; Structural feature; Velocity contrasts; Velocity structure, Shear waves https://www.scopus.com/inward/record.uri?eid=2-s2.0-85040695871&doi=10.1093%2fgji%2fggx059&partnerID=40&md5=83d4363b43fe13422f45dd44a6ed8350 cited By 8 B. Guo C.H. Thurber S.W. Roecker J. Townend C. Rawles C.J. Chamberlain C.M. Boese S. Bannister J. Feenstra J.D. Eccles article Gupta2017641 2017 English 00167622 10.1007/s12594-017-0770-0 Journal of the Geological Society of India 90 Geological Society of India 641-644 CSIR- National Geophysical Research Institute, Hyderabad, 500 007, India 6 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85039438089&doi=10.1007%2fs12594-017-0770-0&partnerID=40&md5=5fc2e73fd628b651bf2e305e32d8e551 cited By 6 H.K. Gupta article Weide2017179 A multidecadal-scale lake-level reconstruction for Lago Wiñaymarca, the southern basin of Lake Titicaca, has been generated from diatom species abundance data. These data suggest that ~6500 cal yr BP Lago Wiñaymarca was dry, as indicated by a sediment unconformity. At ~4400 cal yr BP, the basin began to fill, as indicated by the dominance of shallow epiphytic species. It remained somewhat saline with extensive wetlands and abundant aquatic plants until ~3800 cal yr BP, when epiphytic species were replaced by planktic saline-indifferent species, suggesting a saline shallow lake. Wiñaymarca remained a relatively shallow lake that fluctuated on a multidecadal scale until ~1250 cal yr BP, when freshwater planktic species increased, suggesting a rise in lake level with a concomitant decrease in salinity. The lake became gradually fresher, dominated by deep, freshwater species from ~850 cal yr BP. By ~80 cal yr BP, saline-tolerant species were rare, and the lake was dominated by freshwater planktic diatoms, resembling the fresh and deep lake of today. These results reveal a more dynamic and chronologically specific record of lake-level fluctuations and associated ecological conditions that provide important new data for paleoclimatologists and archaeologists, to better understand human-environmental dynamics during the mid- to late Holocene. Copyright © University of Washington. Published by Cambridge University Press, 2017. Article 2017 10.1017/qua.2017.49 Quaternary Research (United States) 88 179 – 192 2 Bacillariophyta; Phytoplankton; Water; Concomitant decrease; Ecological conditions; Environmental dynamics; Holocenes; Lake level fluctuations; Lake levels; Mid to late Holocene; Tropical Andes; Lakes https://www.scopus.com/inward/record.uri?eid=2-s2.0-85053732457&doi=10.1017%2fqua.2017.49&partnerID=40&md5=180c0c4de1c8b3e886d5a69207a5fbcc Cited by: 26 D. Marie Weide Sherilyn C. Fritz Christine A. Hastorf Maria C. Bruno Paul A. Baker Stéphane Guédron Wout Salenbien article Mishra2017788 A 1251 m thick succession of Deccan lava flows has been recovered by scientific drilling in the Koyna region, western part of the Deccan Volcanic Province (DVP). Forty-six lava flows, starting with the first flow overlying the granitic basement in the region, have been identified through mesoscopic studies of cores obtained from a 1500 m deep borehole KBH7 in Panchgani village of Patan sub-division. Mesoscopic observations supported by petrographic studies bring out the characteristics of the basaltic pile. The salient findings are as follows. The thickness of Deccan trap in the Panchgani area is 1251.20 m, comprising a succession of 40 simple lava flows and 6 compound lava flows. The contact with the underlying granitic basement occurs over a short span of 90 cm. Infra-trappean sediments are absent. Overall, ∼74% of the basaltic pile is constituted of massive basalt and ∼24% vesicular/amygdaloidal basalt. Red bole horizons are observed in 7 flows. Nine giant plagioclase basalt (GPB) flows are identified in the single vertical section. The long basalt core may serve as a model Deccan trap section for correlation with the flows exposed at the surface in the Koyna and surrounding region and support detailed investigations to constrain the duration of Deccan volcanism. © 2017, Geological Society of India. 2017 English 00167622 10.1007/s12594-017-0792-7 Journal of the Geological Society of India 90 Geological Society of India 788-794 Borehole Geophysics Research Laboratory (BGRL), Ministry of Earth Sciences, Karad, 415 114, India; CSIR-National Geophysical Research Institute, Hyderabad, 500 007, India 6 basement rock; Deccan Traps; drilling; flood basalt; lava flow; petrography; plagioclase; volcanism; volcanology, India; Koyna; Maharashtra https://www.scopus.com/inward/record.uri?eid=2-s2.0-85039461106&doi=10.1007%2fs12594-017-0792-7&partnerID=40&md5=791eabdb679ec115ca55804c00882fed cited By 16 S. Mishra S. Misra D. Vyas D. Nikalje A. Warhade S. Roy article Lu2017199 Article 2017 10.1016/j.gloplacha.2017.04.003 Global and Planetary Change 152 199 – 208 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85018876049&doi=10.1016%2fj.gloplacha.2017.04.003&partnerID=40&md5=f576dae2f6e4a55c2a993003402c9bd9 Cited by: 21 Yin Lu Nicolas Waldmann Dani Nadel Shmuel Marco article Yan20171465 Article 2017 0956-540X 10.1093/gji/ggw457 Geophysical Journal International 208 1465 – 1489 3 inverse theory, Magnetotellurics, Europe, Downhole methods, Continental tectonics https://www.scopus.com/inward/record.uri?eid=2-s2.0-85014384679&doi=10.1093%2fgji%2fggw457&partnerID=40&md5=390b9d27000d3f817619b4eebec29808 Cited by: 19; All Open Access, Green Open Access Ping Yan Maria A. Garcia Juanatey Thomas Kalscheuer Christopher Juhlin Peter Hedin Alexandros Savvaidis Henning Lorenz Jochem Kück article Friese2017200 Subsurface exploration relies on drilling. Normally drilling requires a drilling fluid that will infiltrate into the drill core. Drilling fluid contains non-indigenous materials and microbes from the surface, so its presence renders a sample unsuitable for microbiological and many other analyses. Because infiltration cannot be avoided, it is of paramount importance to assess the degree of contamination to identify uncontaminated samples for geomicrobiological investigations. To do this, usually a tracer is mixed into the drilling fluid. In past drilling operations a variety of tracers have been used, each has specific strengths and weaknesses. For microspheres the main problem was the high price, which limited their use to spot checks or drilling operations that require only small amounts of drilling fluid. Here, we present a modified microsphere tracer approach that uses an aqueous fluorescent pigment dispersion with a similar concentration of fluorescent particles as previously used microsphere tracers. However, it costs four orders of magnitude less, allowing for a more liberal use even in large operations. Its applicability for deep drilling campaigns was successfully tested during two drilling campaigns of the International Continental Drilling Program (ICDP) at Lake Towuti, Sulawesi, Indonesia, and Lake Chalco, Mexico. Quantification of the tracer requires only a fluorescence microscope or a flow cytometer. The latter allowing for high-resolution data to be obtained directly on-site within minutes and with minimal effort, decreasing sample processing times substantially relative to traditional tracer methods. This approach offers an inexpensive, rapid, but powerful alternative technique for contamination assessment during drilling campaigns. © 2017 Association for the Sciences of Limnology and Oceanography. Article 2017 English 15415856 10.1002/lom3.10159 Limnology and Oceanography: Methods 15 Wiley Blackwell 200 – 211 2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85012942108&doi=10.1002%2flom3.10159&partnerID=40&md5=3510ecc7a8321f77eb30ea0e69c59c51 Cited by: 19; All Open Access, Green Open Access, Hybrid Gold Open Access André Friese Jens Kallmeyer Jan Axel Kitte Ivan Montaño Martínez Satria Bijaksana Dirk Wagner article Toy2017497 During the second phase of the Alpine Fault, Deep Fault Drilling Project (DFDP) in the Whataroa River, South Westland, New Zealand, bedrock was encountered in the DFDP-2B borehole from 238.5–893.2 m Measured Depth (MD). Continuous sampling and meso- to microscale characterisation of whole rock cuttings established that, in sequence, the borehole sampled amphibolite facies, Torlesse Composite Terrane-derived schists, protomylonites and mylonites, terminating 200–400 m above an Alpine Fault Principal Slip Zone (PSZ) with a maximum dip of 62°. The most diagnostic structural features of increasing PSZ proximity were the occurrence of shear bands and reduction in mean quartz grain sizes. A change in composition to greater mica:quartz + feldspar, most markedly below c. 700 m MD, is inferred to result from either heterogeneous sampling or a change in lithology related to alteration. Major oxide variations suggest the fault-proximal Alpine Fault alteration zone, as previously defined in DFDP-1 core, was not sampled. © 2017 The Royal Society of New Zealand. 2017 English 00288306 10.1080/00288306.2017.1375533 New Zealand Journal of Geology and Geophysics 60 Taylor and Francis Asia Pacific 497-518 Department of Geology, University of Otago, Dunedin, New Zealand; Hokkaido University - Earth and Planetary System Science, Department of Natural History Sciences, Graduate School of Sciences, Sapporo, Japan; School of Geography, Environment, and Earth Sciences, Victoria University of Wellington, Wellington, New Zealand; Department of Earth and Ocean Sciences, University of Liverpool, Liverpool, United Kingdom; Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI, United States; School of Geology & Geophysics, University of Oklahoma, Norman, OK, United States; GNS Science Ltd, Dunedin, New Zealand; Institute of Earth and Environmental Science, Universität Potsdam, Potsdam, Germany; Microscopy & Microanalysis Facility, John de Laeter Centre, Curtin University, Perth, Australia; Department of Geological Sciences, Central Washington University, Ellensburg, WA, United States; Department of Science, Osaka University, Toyonaka, Osaka, Japan; Department of Geosphere Sciences, Yamaguchi University, Yamaguchi, Japan; Ube Industrial Corporation, Yamaguchi, Japan; US Geological Survey, Menlo Park, CA, United States; Department of Earth & Planetary Sciences, McGill University, Montreal, QC, Canada; Ocean & Earth Science, National Oceanography Centre Southampton, University of Southampton, Southampton, United Kingdom; ScopeM - ETH Zürich, Zurich, Switzerland; Faculty of Science, Shinshu University, Nagano, Japan; Department of Geosciences, University of Utrecht, Utrecht, Netherlands; Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences, Potsdam, Germany; Geological Survey of Japan, Ibaraki, Japan; Department of Geoscience, University of Wisconsin–Madison, Madison, WI, United States; Rock and Sediment Laboratory, Pennsylvania State University, University Park, PA, United States; Department of Earth Sciences, University of California, Riverside, CA, United States; School of Environment, University of Auckland, Auckland, New Zealand; CNRS, Université de Montpellier, Montpellier, Languedoc-Roussillon, France; ISTerre, Université Grenoble Alpes, Saint-Martin-d'Heres, Rhône-Alpes, France; Department of Geoscience Madison, University of Wisconsin Madison, Wisconsin, United States; Department of Physics, University of Alberta, Edmonton, AB, Canada; Faculty of Science, Macquarie University, Macquarie Park, New South Wales, Australia; Graduate School of International Resource Sciences, Department of Earth Resource Science, Akita University, Akita, Japan; Antarctic Research Centre, Victoria University of Wellington, Wellington, New Zealand; Institute of Geophysics, Victoria University of Wellington, Wellington, New Zealand; DFDP-2 Science Team, c/- International Continental Scientific Drilling Program (ICDP), Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences, Telegrafenberg, Potsdam, D-14473, Germany 4 bedrock; cataclasite; core analysis; drilling; fault zone; mylonite; sedimentary sequence; shear band; slip rate; structural geology, Alpine Fault Zone; New Zealand; South Island https://www.scopus.com/inward/record.uri?eid=2-s2.0-85031489907&doi=10.1080%2f00288306.2017.1375533&partnerID=40&md5=5aed5ba39ad828aa4571f18bbf518435 cited By 22 V.G. Toy R. Sutherland J. Townend M.J. Allen L. Becroft A. Boles C. Boulton B. Carpenter A. Cooper S.C. Cox C. Daube D.R. Faulkner A. Halfpenny N. Kato S. Keys M. Kirilova Y. Kometani T. Little E. Mariani B. Melosh C.D. Menzies L. Morales C. Morgan H. Mori A. Niemeijer R. Norris D. Prior K. Sauer A.M. Schleicher N. Shigematsu D.A.H. Teagle H. Tobin R. Valdez J. Williams S. Yeo L.-M. Baratin N. Barth A. Benson C. Boese B. Célérier C.J. Chamberlain R. Conze J. Coussens L. Craw M.-L. Doan J. Eccles J. Grieve J. Grochowski A. Gulley J. Howarth K. Jacobs L. Janku-Capova T. Jeppson R. Langridge D. Mallyon R. Marx C. Massiot L. Mathewson J. Moore O. Nishikawa B. Pooley A. Pyne M.K. Savage D. Schmitt S. Taylor-Offord P. Upton K.C. Weaver T. Wiersberg M. Zimmer DFDP-2 Science Team article Friese2017200 Subsurface exploration relies on drilling. Normally drilling requires a drilling fluid that will infiltrate into the drill core. Drilling fluid contains non-indigenous materials and microbes from the surface, so its presence renders a sample unsuitable for microbiological and many other analyses. Because infiltration cannot be avoided, it is of paramount importance to assess the degree of contamination to identify uncontaminated samples for geomicrobiological investigations. To do this, usually a tracer is mixed into the drilling fluid. In past drilling operations a variety of tracers have been used, each has specific strengths and weaknesses. For microspheres the main problem was the high price, which limited their use to spot checks or drilling operations that require only small amounts of drilling fluid. Here, we present a modified microsphere tracer approach that uses an aqueous fluorescent pigment dispersion with a similar concentration of fluorescent particles as previously used microsphere tracers. However, it costs four orders of magnitude less, allowing for a more liberal use even in large operations. Its applicability for deep drilling campaigns was successfully tested during two drilling campaigns of the International Continental Drilling Program (ICDP) at Lake Towuti, Sulawesi, Indonesia, and Lake Chalco, Mexico. Quantification of the tracer requires only a fluorescence microscope or a flow cytometer. The latter allowing for high-resolution data to be obtained directly on-site within minutes and with minimal effort, decreasing sample processing times substantially relative to traditional tracer methods. This approach offers an inexpensive, rapid, but powerful alternative technique for contamination assessment during drilling campaigns. © 2017 Association for the Sciences of Limnology and Oceanography. 2017 English 15415856 10.1002/lom3.10159 Limnology and Oceanography: Methods 15 Wiley Blackwell 200-211 GFZ German Research Center For Geosciences, Section 5.3. Geomicrobiology, Potsdam, 14473, Germany; Department of Geoarchives, Laboratorio de Paleolimnologia, Instituto de Geofísica, UNAM, Mexico City, Mexico; Faculty of Mining and Petroleum Engineering, Institut Teknologi Bandung, Bandung, Indonesia 2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85012942108&doi=10.1002%2flom3.10159&partnerID=40&md5=3510ecc7a8321f77eb30ea0e69c59c51 cited By 18 A. Friese J. Kallmeyer J.A. Kitte I.M. Martínez S. Bijaksana D. Wagner ICDP Lake Chalco Drilling Science Team Team article Hrubcová20172846 The Eger Rift is an active element of the European Cenozoic Rift System associated with intense Cenozoic intraplate alkaline volcanism and system of sedimentary basins. The intracontinental Cheb Basin at its western part displays geodynamic activity with fluid emanations, persistent seismicity, Cenozoic volcanism, and neotectonic crustal movements at the intersections of major intraplate faults. In this paper, we study detailed geometry of the crust/mantle boundary and its possible origin in the western Eger Rift. We review existing seismic and seismological studies, provide new interpretation of the reflection profile 9HR, and supplement it by new results from local seismicity. We identify significant lateral variations of the high-velocity lower crust and relate them to the distribution and chemical status of mantle-derived fluids and to xenolith studies from corresponding depths. New interpretation based on combined seismic and isotope study points to a local-scale magmatic emplacement at the base of the continental crust within a new rift environment. This concept of magmatic underplating is supported by detecting two types of the lower crust: a high-velocity lower crust with pronounced reflectivity and a high-velocity reflection-free lower crust. The character of the underplated material enables to differentiate timing and tectonic setting of two episodes with different times of origin of underplating events. The lower crust with high reflectivity evidences magmatic underplating west of the Eger Rift of the Late Variscan age. The reflection-free lower crust together with a strong reflector at its top at depths of ~28–30 km forms a magma body indicating magmatic underplating of the late Cenozoic (middle and upper Miocene) to recent. Spatial and temporal relations to recent geodynamic processes suggest active magmatic underplating in the intracontinental setting. ©2017. American Geophysical Union. All Rights Reserved. Article 2017 English 02787407 10.1002/2017TC004710 Tectonics 36 Blackwell Publishing Ltd 2846 – 2862 12 Eger; Heves; Hungary; Alkalinity; Reflection; Seismology; Velocity; Alkaline volcanism; Continental crusts; Eger Rift; Geodynamic process; Lateral variations; Lower crust; Magma bodies; Underplating; crust-mantle boundary; crustal movement; geodynamics; intraplate process; magmatic differentiation; rift zone; seismic reflection; underplating; Geodynamics https://www.scopus.com/inward/record.uri?eid=2-s2.0-85040814317&doi=10.1002%2f2017TC004710&partnerID=40&md5=370c3f891f5e385841d66a0772395b7e Cited by: 21; All Open Access, Green Open Access Pavla Hrubcová Wolfram H. Geissler Karin Bräuer Václav Vavryčuk Čestmír Tomek Horst Kämpf article Giannopoulos2017284 Three years of continuous waveform data recorded at 22 stations from the Corinth Rift Laboratory and the Hellenic Unified Seismological Network are used to perform an ambient noise surface wave tomography of the western Corinth Rift. All available vertical component time-serieswere cross-correlated to extract empirical Rayleigh-wave Green's functions. Group velocity dispersion curves were measured for each station-pair by applying frequency-time analysis and then inverted to build 2-D group velocity maps between 1 and 6 s period. Finally, we locally inverted these velocity maps using a neighbourhood algorithm to assess the 3-D shear-velocity model of the shallow crustal structure of the western Corinth Rift. Across all studied periods the southern coast of the Corinth Gulf is generally imaged as a region of lower velocities compared to the northern coast. At periods up to 3 s, the spatial variation of the group velocities is correlated with the surface geology of the area. Lower velocities are observed in areas where mostly Plio-Quaternary syn-rift sediments are present, such as offshore regions of the rift, the Mornos delta and the largest part of the southern coast. Higher velocities are observed in pre-rift basement structures which are dominated mostly by carbonates. At periods above 3 s, where Rayleigh-waves begin to sense deeper structures below the sediments within the underlying basement, our study highlights the presence of a distinct zone of lower velocities across the southern part of the rift with an elongation in the WNW-ESE direction. The interpretation of this low velocity includes two arguments, the present-day active tectonic regime and the possible involvement of fluids circulation processes at depth within a highly fractured upper crust in the vicinity of the major faults zones. In general, the results demonstrate good agreement with the major geological and tectonic features of the area, as well as with previous local earthquake tomography studies and support the assumption of fluid circulations at depth. This work intends to be the base for further investigations towards the study of the Corinth Rift structure using long-time series of ambient noise data. © The Authors 2017. Article 2017 English 0956540X 10.1093/GJI/GGX298 Geophysical Journal International 211 Oxford University Press 284 – 299 1 Corinth Rift; Greece; Gulf of Corinth; Ionian Sea; Mediterranean Sea; Acoustic noise; Buildings; Coastal engineering; Group velocity dispersion; Interferometry; Light velocity; Rayleigh waves; Seismology; Surface waves; Tectonics; Three dimensional computer graphics; Ambient noise tomographies; Continuous waveforms; Crustal structure; Group velocity dispersion curve; Neighbourhood algorithms; Seismic tomography; Shear velocity models; Surface-wave tomography; algorithm; ambient noise; crustal structure; Green function; Rayleigh wave; seismic velocity; seismology; tomography; Shear flow https://www.scopus.com/inward/record.uri?eid=2-s2.0-85032625182&doi=10.1093%2fGJI%2fGGX298&partnerID=40&md5=27343f9953364f611744591dec22585d Cited by: 6; All Open Access, Green Open Access Dimitrios Giannopoulos Diane Rivet Efthimios Sokos Anne Deschamps Aurelien Mordret Hélène Lyon-Caen Pascal Bernard Paraskevas Paraskevopoulos G-Akis Tselentis article Peng2017865 The Chinese Continental Scientific Drilling Project of the Cretaceous Songliao Basin (CCSD-SK) provides an excellent opportunity to understand the response of terrestrial environments to greenhouse climate change in the Cretaceous. We conducted a palaeoenvironmental study of the Late Cretaceous Qingshankou Formation (K2qn) based on geochemical log data from the SK-2 east borehole. According to the characteristic of Ti mainly from terrigenous minerals, the content of authigenic elements was calculated. Correlation space was proposed to study the variation of the correlation between two log curves along the depth. Palaeoenvironmental proxies were selected from log data to study the evolution of the climate and lake, productivity of the paleolake, and organic matter deposition. The results demonstrate that the productivity of the paleolake was driven by chemical weathering in K2qn, in which the first section of the Qingshankou Formation (K2qn1) has higher productivity than the second and third sections of the Qingshankou Formation (K2qn2+3). The high content of pyrite in several thin layers reveals lake water of high sulfate concentration. This may have been caused by acid rain related to large volcanic activity. In K2qn2+3, several periods of high productivity without the formation of source rocks and high organic matter content were identified. This may show that organic matter deposition was limited by low accommodation space or oxidation environment. Therefore, the preservation condition is suggested as the main controlling factor of organic matter deposition in K2qn. © 2017 Sinopec Geophysical Research Institute. Article 2017 English 17422132 10.1088/1742-2140/aa6b2f Journal of Geophysics and Engineering 14 Institute of Physics Publishing 865 – 877 Key Laboratory of Geo-detection, China University of Geosciences, Ministry of Education, Beijing, 100083, China; School of Geophysics and Information Technology, China University of Geosciences, Beijing, 100083, China; ConocoPhillips School of Geology and Geophysics, University of OklahomaOK 73019, United States; Development and Research Center, China Geological Survey, Beijing, 100037, China 4 China; Songliao Basin; borehole; Chinese Continental Scientific Drilling Project; Cretaceous; deposition; environmental research; geochemistry; organic matter; paleoenvironment; productivity; proxy climate record; source rock; terrigenous deposit https://www.scopus.com/inward/record.uri?eid=2-s2.0-85021651443&doi=10.1088%2f1742-2140%2faa6b2f&partnerID=40&md5=c3fd56880124eec088b00066f4692675 Cited by: 8; All Open Access, Bronze Open Access Cheng Peng Changchun Zou Li Pan Yixiong Niu article Nickschick20172915 The Hartoušov mofette field in NW Bohemia, Czech Republic, is characterized by strong CO2 degassing from the Lithospheric Mantle. In a test survey using electrical resistivity tomography, we observed changes over time in the subsurface structure beneath heavily CO2 degassing spots to depths of about 40 m and compared them to CO2 gas flux and soil gas mappings from previous studies. Changes in the electrical resistivity were measured between September 2012 and October 2013 at irregular intervals and highlight large variations in the resistivity distribution where the CO2 degassing was strongest (56 × 103 g m−2 day−1), indicating a fluid-induced change of properties of the underlying clayey sediments. Positive and negative anomalies in the electric self-potential parallel to the ERTs can be found where CO2 degassing occurs which indicates varying ascent or descent of fluids within these spots. Some degassing spots seem not to be actively degassing continuously over time, which can also be observed by other studies in the same area. We suggest that future gas mappings are accompanied by methods that observe the state of fluid systems at subsurface over time, e.g. electric resistivity tomography and self potential. © 2017, Springer-Verlag Berlin Heidelberg. 2017 English 14373254 10.1007/s00531-017-1470-0 International Journal of Earth Sciences 106 Springer Verlag 2915-2926 Institute for Geophysics and Geology, University of Leipzig, Talstrasse 35, Leipzig, 04103, Germany; German Research Centre for Geosciences GFZ Potsdam, Section 4.3 Telegrafenberg, Potsdam, 14473, Germany; Institute of Geophysics, Academy of Sciences of the Czech Republic, Bocˇní II, Praha 4, 141 31, Czech Republic 8 carbon dioxide; carbon flux; degassing; electrical resistivity; fumarole; mantle structure; mapping; temporal variation; tomography, Bohemia; Cheb Basin; Czech Republic; Karlovarsky https://www.scopus.com/inward/record.uri?eid=2-s2.0-85016045453&doi=10.1007%2fs00531-017-1470-0&partnerID=40&md5=acd19025974be7143993fda13e486fa9 cited By 6 T. Nickschick C. Flechsig C. Meinel J. Mrlina H. Kämpf article Melles201743 Lake Elgygytgyn in the north-eastern Russian Arctic became the target of extensive international site surveys in the late 1990s, with complex geoscientific fieldwork conducted in 1998, 2000, and 2003. The surveys strongly supported the hypothesis that the lake hosts a nearly continuous sediment record, which is highly sensitive to climatic and environmental changes and covers the time since the lake formation by a meteorite impact some 3.6 Ma ago. These promising findings led to deep drilling operations within the scope of the International Continental Scientific Drilling Program (ICDP) in 2008 and 2009, during which 141 m of permafrost deposits in the catchment, the 318 m thick lake sediment succession in the lake centre, and about 200 m of impact rocks underneath were drilled. Palaeoenvironmental and palaeoclimatological research on the Quaternary part of the lake sediment record revealed that full glacial conditions, with mean annual air temperatures at least 3.3 ±0.9 °C lower than today, first commenced at the Pliocene/ Pleistocene boundary 2.6 Ma ago. They gradually increased in frequency from ca. 2.3 to 1.8 Ma, eventually concurring with all global glacials and several stadials. The interglacials at Lake Elgygytgyn significantly differ in intensity. So-called super interglacials irregularly occurred throughout the Quaternary, including Marine Isotope Stages 11.3 and 31, when mean temperatures of the warmest month and annual precipitation were up to 4-5 °C and ~300 mm higher than today, respectively. According to climate modelling these climatic settings cannot in all cases be traced back to orbital forcing or greenhouse gas concentrations. They are, at least partly, the result of other processes and feedbacks in the climate system. A remarkable coincidence of the super interglacials with diatomite layers in the Antarctic ANDRILL 1B record suggests that they were associated with considerable retreats of the West Antarctic Ice Sheet. The ice decay may have caused reductions in Antarctic Bottom Water formation, its transport to the Pacific Ocean, and its upwelling in the north-western Pacific, and potentially increased warm-water intrusions through the Bering Strait into the Arctic Ocean. © Alfred Wegener Institut fur Polar- und Meeresforschung. All rights reserved. 2017 English 00322490 10.2312/polarforschung.87.1.43 Polarforschung 87 Alfred Wegener Institut fur Polar- und Meeresforschung 43-60 University of Cologne, Institute of Geology and Mineralogy, Zölpicher Str. 49a, Cologne, D-50674, Germany 1 climate variation; environmental change; glacial-interglacial cycle; lacustrine deposit; paleoclimate; paleoenvironment; paleolimnology; Quaternary, Chukchi; Elgygytgyn Lake; Russian Federation https://www.scopus.com/inward/record.uri?eid=2-s2.0-85055843734&doi=10.2312%2fpolarforschung.87.1.43&partnerID=40&md5=c6cba7d5779c380b3a2b9340737c4e33 cited By 0 M. Melles V. Wennrich article Mousavi201764 We present a three-dimensional (3-D) P-wave attenuation (Qp) model for the geodynamically active swarm earthquake area of West Bohemia/Vogtland in the Czech/German border region. Path-averaged attenuation t* is calculated from amplitude spectra of time windows around the P-wave arrivals of local earthquakes. Average t/t* value or Qp for stations close to Nový Kostel are very low (< 150) compared to that of stations located further away from the focal zone (increases up to 500 within 80 km distance). The SIMUL2000 tomography scheme is used to invert the t* for P-wave attenuation perturbation. Analysis of resolution shows that our model is well-resolved in the vicinity of earthquake swarm hypocenters. The prominent features of the model are located around Nový Kostel focal zone and its northern vicinity. Beneath Nový Kostel a vertically stretched (down to depth of 11 km) and a highly attenuating body is observed. We believe that this is due to fracturing and high density of cracks inside the weak earthquake swarm zone in conjunction with presence of free gas/fluid. Further north of Nový Kostel two highly attenuating bodies are imaged which could represent fluid channels toward the surface. The eastern anomaly shows a good correlation with the fluid accumulation area which was suggested in 9HR seismic profile. © 2016 Elsevier B.V. 2017 English 00401951 10.1016/j.tecto.2016.12.010 Tectonophysics 695 Elsevier B.V. 64-75 Institute of Geophysics and Geology, University of Leipzig, Talstr. 35, Leipzig, D-4103, Germany; GFZ German Research Centre for Geosciences, Telegrafenberg, Potsdam, D-14473, Germany; Research School of Earth Sciences, Australian National University, Canberra, 2601, Australia Seismic waves, Body waves; Earthquake swarms; Europe; Seismic attenuation; Seismic tomography, Earthquakes, amplitude; body wave; earthquake hypocenter; earthquake swarm; P-wave; seismic attenuation; seismic tomography; seismicity; structural geology, Bohemia; Czech Republic; Germany; Vogtland https://www.scopus.com/inward/record.uri?eid=2-s2.0-85006172660&doi=10.1016%2fj.tecto.2016.12.010&partnerID=40&md5=9f1730f6627f01f2df7f18546df9aceb cited By 13 S. Mousavi C. Haberland B. Hejrani M. Korn article 2017 10.1126/science.aan6905 Science P. Voosen article Williams201735 It is now commonplace for non-destructive X-ray computed tomography (CT) scans to be taken of core recovered during a drilling project. However, other forms of tomographic scanning are available, and these may be particularly useful for core that does not possess significant contrasts in density and/or atomic number to which X-rays are sensitive. Here, we compare CT and neutron tomography (NT) scans of 85mm diameter core recovered during the first phase of the Deep Fault Drilling Project (DFDP-1) through New Zealand's Alpine Fault. For the instruments used in this study, the highest resolution images were collected in the NT scans. This allows clearer imaging of some rock features than in the CT scans. However, we observe that the highly neutron beam attenuating properties of DFDP-1 core diminish the quality of images towards the interior of the core. A comparison is also made of the suitability of these two scanning techniques for a drilling project. We conclude that CT scanning is far more favourable in most circumstances. Nevertheless, it could still be beneficial to take NT scans over limited intervals of suitable core, where varying contrast is desired. © Author(s) 2017. 2017 English 18168957 10.5194/sd-22-35-2017 Scientific Drilling 22 Copernicus GmbH 35-42 Department of Geology, University of Otago, PO Box 56, Dunedin, 9054, New Zealand; Australian Centre for Neutron Scattering, Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW 2234, Australia Atoms; Neutrons; Recovery; Scanning; Tomography, Atomic numbers; Drilling projects; Highest resolutions; Neutron tomography; Non destructive; Scanning techniques; Tomographic scanning; X-ray computed tomography, Computerized tomography https://www.scopus.com/inward/record.uri?eid=2-s2.0-85020113625&doi=10.5194%2fsd-22-35-2017&partnerID=40&md5=763e5e11e7c24ee60df4c2de86c73e31 cited By 3 J.N. Williams J.J. Bevitt V.G. Toy article Drabon2017803 Article 2017 10.1130/G39255.1 Geology 45 803 – 806 9 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85028516716&doi=10.1130%2fG39255.1&partnerID=40&md5=e60730039b9cff9f7bc24bb472101ced Cited by: 36 Nadja Drabon Donald R. Lowe Gary R. Byerly Jacob A. Harrington article Misra2017776 The Koyna region, located in the Deccan Flood Basalt Province of western peninsular India has been experiencing reservoir triggered seismicity since the impoundment of the Shivajisagar water reservoir in 1962. Scientific drilling carried out to 1522 m depth in the vicinity of the seismogenic zone exposed the granitic basement that lay below the Deccan Traps and provided a unique opportunity to study the rock types, petrological characteristics and microstructures. Cores obtained from drilling at four sites considered to be representative of the Koyna region, were studied. The boreholes include KBH-1 (Rasati) in the northern part, KBH-5 (Phansavle) in the western part, KBH-6 (Ukhalu) and KBH-7 (Panchgani) in the eastern part of the region. Each borehole penetrates the entire pile of Deccan basalt and pass through a few hundred metres of the granitic basement. The salient results are as follows: (i) The basement granitoids are dominantly composed of granite-gneiss, granite and migmatitic gneiss, typical of cratonic gneiss exposed in peninsular India. (ii) Petrology and microstructure study confirm the occurrence of strained quartz and unstrained plagioclase feldspars in the basement granitoids. (iii) Localized fault zones within the basement section, with prominent evidences of fault breccia, fault gouge, slicken lines with slickensides and pseudotachylite veins are observed in the individual boreholes. (iv) Anastomosing fracture network within these fault zones are good pathways for water channelization, which is supported by the higher abundances of ferruginous and siliceous secondary precipitations following the fractures. © 2017, Geological Society of India. 2017 English 00167622 10.1007/s12594-017-0790-9 Journal of the Geological Society of India 90 Geological Society of India 776-782 Borehole Geophysics Research Laboratory (BGRL), Ministry of Earth Sciences, Karad, 415114, India; CSIR-National Geophysical Research Institute, Hyderabad, 500007, India 6 basalt; basement rock; Deccan Traps; drilling; gneiss; granite; microstructure; petrology; seismic zone, India; Koyna; Maharashtra https://www.scopus.com/inward/record.uri?eid=2-s2.0-85039452603&doi=10.1007%2fs12594-017-0790-9&partnerID=40&md5=c6c5d1ed23696d33e7ec55fedd369314 cited By 22 S. Misra V. Bartakke G. Athavale V.V. Akkiraju D. Goswami S. Roy article Kessler2017476 Project HOTSPOT, the Snake River Scientific Drilling Project (International Continental Scientific Drilling Program), tested for deep geothermal resources and examined the petrology of volcanic rocks with three drillholes in the central and western Snake River Plain (western USA). The MH-2 drillhole targeted fractured crystalline and hydrothermally altered basalt in the area of the Mountain Home Air Force Base (Idaho) to a total depth of 1821 m. At 1745 m depth the drillhole encountered flowing artesian hydrothermal fluids of at least 150 °C. We integrate geological analyses of core, image log, and borehole geophysical data, and in situ stress analyses to describe the structural environment that produces permeability for artesian flow. The rocks in the lower 540 m of the drillhole consist of basalt flows as much as 30 m thick, altered basalt, and thin sedimentary horizons. The mechanical stratigraphy is defined by nine mechanical horizons that are in three ranges of rock strength on the basis of experimentally determined strength data, core logging, and geophysical log signatures. Hydrothermal alteration products and mineralization in the core are associated with three highly faulted sections; the lowermost section is associated with the zone of flowing thermal water. Shear slip indicators on faults observed in core indicate slip ranging from pure strike slip to normal failure mechanisms in the stronger horizons. The borehole breakouts indicate that the maximum horizontal stress, SH, is oriented 047° ± 7°, and drilling-induced tensile fractures indicate that SH is oriented at 67° ± 21°.The in situ stress orientations exhibit little variation over the depth of the measured interval, but the SH magnitude varies with depth, and is best explained by an oblique normal fault stress regime.The geomechanical model indicates that if pore pressures at depth are elevated above the normal hydrostatic gradient, as observed here, the system has the potential to deform by mixed normal and strike-slip failure. Our observations and interpretations suggest that the MH-2 borehole was drilled into oblique normal faults that intersect a buried 300°-trending fault block masked by the basaltic volcanic complex. These data indicate that the transition from the central to western Snake River Plain is characterized by complex structures developed in response to a transitional stress state related to Snake River Plain and western Basin and Range stress regimes. The western Basin and Range stress and tectonic regime may extend from northern Nevada into western Idaho and may enhance the potential for geothermal resources by creating interconnected fracture and fault-related permeability at depth. © 2017 Geological Society of America. Article 2017 English 19418264 10.1130/L609.1 Lithosphere 9 Geological Society of America 476 – 498 Department of Geology, Utah State University, 4505 Old Main Hill, Logan, UT 84322, United States; Department of Physics, University of Alberta, 4-181 CCIS, Edmonton, AB T6G 2E1, Canada; Occidental Petroleum Corporation, 5 Greenway Plaza, Houston, TX 77046, United States; Anadarko Petroleum Company, 1201 Lake Robbins Drive, The Woodlands, TX 77380, United States 3 Idaho; Snake River Plain; United States; Air; Basalt; Boreholes; Boring; Clay alteration; Core analysis; Faulting; Fracture; Geology; Geophysics; Geothermal fields; Geothermal prospecting; Horizontal drilling; Rivers; Rock drills; Sedimentary rocks; Software testing; Stratigraphy; Stresses; Strike-slip faults; Structural geology; Volcanic rocks; Volcanoes; Well logging; Continental scientific drillings; Drilling-induced tensile fractures; Geothermal exploration; Hydrostatic gradients; Hydrothermal alterations; Mechanical stratigraphy; Sedimentary horizons; Structural environment; artesian well; borehole geophysics; geological survey; geomechanics; geothermal system; hydrothermal activity; hydrothermal fluid; in situ stress; petrology; strike-slip fault; Fault slips https://www.scopus.com/inward/record.uri?eid=2-s2.0-85019883682&doi=10.1130%2fL609.1&partnerID=40&md5=98f280eff23cf4b3e1bafa8596f7e582 Cited by: 9; All Open Access, Bronze Open Access, Green Open Access J.A. Kessler K.K. Bradbury J.P. Evans M.A. Pulsipher J.W. Shervais F.E. Rowe J. Varriale article He2017368 Marine gas hydrate is an important resource of clean energy for the future, but its exploitation requires not only the innovation of development techniques but also serious consideration of protection of marine environment. For a timely response to production process, monitoring of the dynamic change of gas hydrate reservoir in real time is a basic requirement for a successful exploitation. However, in previous successful gas hydrate production experiments, either in terrestrial permafrost area (Mallik of Canada and Ignik Sikumi of USA) or on continental slope in deep sea (Nankai Trough of Japan), monitoring was carried out mainly through the instruments installed in the two or three observation wells which were only tens of meters away from the production well, and consequently the monitoring might have covered only a limited area. At the present the monitoring technique for large-scale monitoring of gas hydrate reservoir has not been established worldwide, even systematic discussion and scheme design are absent. Based on the acoustic and electrical responses to the saturation change and granular contact mode of gas hydrate layer, several seismic and electromagnetic exploration methods have been compared to see their feasibility and merits and drawbacks for large-scale monitoring of marine gas hydrate development, and an advanced geophysical monitoring scheme is proposed for the upcoming gas hydrate experimental production in South China Sea and future commercial exploitation. The integrated geophysical monitoring system is comprised of (1) a set of geophysical sensors to be installed in the observation wells, which will continuously collect the key physical parameters as temperature, pressure, electrical resistivity, streaming potential, heat flux, etc.; (2) a high sensitive and endurable full fiber 4-component ocean bottom seismic cable system to record the time lapse variations of reservoir acoustic properties of both compressive and shear waves; (3) a net of multifunctional ocean bottom nodes around the production well to measure the seafloor surface deformation/depression during production, and to directly detect and visually observe possible methane leakage. On a well designed protocol, this monitoring system can quantitatively measure the key geophysical variations associated with gas hydrate dissociation, and the data to be acquired will provide scientific basis for production optimization, environment protection and risk assessment for marine gas hydrate exploitation. © 2017, Editorial Office of Earth Science Frontiers. All right reserved. 2017 Chinese 10052321 10.13745/j.esf.yx.2016-11-27 Earth Science Frontiers 24 Science Frontiers editorial department 368-382 School of Earth and Space Sciences, Peking University, Key Laboratory of Orogenic Belts and Crustal Evolution, Beijing, 100871, China; Department of Energy & Resources Engineering, College of Engineering, Peking University, Beijing, 100871, China; Institute of Ocean Research, Peking University, Beijing, 100871, China; Guangzhou Marine Geological Survey, China Geological Survey, Guangzhou, 510760, China 5 Acoustic properties; Deformation; Earthquake effects; Electromagnetic prospecting; Gas hydrates; Gases; Geophysics; Heat flux; Hydration; Risk assessment; Seismology; Shear flow; Shear waves, Commercial exploitation; Gas-hydrate production; Geophysical monitoring; MCSEM; Production optimization; Reservoir monitoring; Seafloor deformation; Seismic system, Monitoring https://www.scopus.com/inward/record.uri?eid=2-s2.0-85029622267&doi=10.13745%2fj.esf.yx.2016-11-27&partnerID=40&md5=9a932a1d6253eadc0c7f868359c75165 cited By 13 T. He H. Lu J. Lin Y. Dong J. He conference Shervais20172328 Play Fairway Analysis (PFA) is a methodology adapted from the petroleum industry that integrates data at the regional or basin scale to define favorable plays for exploration in a systematic fashion. Phase 2 of our Play Fairway Analysis of the Western Snake River Plain (WSRP) province in southern Idaho had three primary goals: first, to fill data gaps in critical areas in order to better define potential prospects, second, to integrate these data into new thermal and structural models, and finally, to infer the location of potential resources and drilling targets that could be validated during Phase 3. Prospects in the WSRP identified as potential target resources for Phase 3 validation include the Mountain Home region close to the Air Force Base, and the Camas Prairie. The Mountain Home region represents a blind geothermal resource in an area of high heat flow and young volcanism. The Camas Prairie is a, structurally controlled resource in an area with indicators of magmatic heat. New geophysical data acquired at these sites includes reflection seismic, gravity and magnetic surveys, and a magnetotelluric field survey. New geochemical data collection focused on the Camas Prairie, and included the aqueous and isotope geochemistry of hot springs, cold springs, and wells (geothermal, groundwater, and irrigation). New field mapping, sampling, and basalt flow chronology was also conducted at Camas Prairie. Integrated results from Phase 1 and 2 studies suggest that the system near the Mountain Home Air Force Base is located at ∼1.5-2.3 km depth, and the structurallycontrolled system at Camas Prairie is shallower, with upper reservoir depths perhaps only ∼0.5-0.7 km. 2017 English 0934412227 01935933 Transactions - Geothermal Resources Council 41 Geothermal Resources Council 2328-2345 Utah State University, Logan, UT, United States; US Geological Survey, Menlo Park, CA, United States; DOSECC Exploration Services, Salt Lake City, UT, United States; Leidos, San Diego, CA, United States; Boise State University, Boise, ID, United States; Lawrence Berkeley National Laboratory, Berkeley, CA, United States; Idaho National Laboratory, Idaho Falls, ID, United States; National Renewable Energy Lab (NREL), Golden, CO, United States Exploratory geochemistry; Geographic information systems; Geothermal fields; Groundwater; Groundwater geochemistry; Hot springs; Landforms; Military aviation; Petroleum industry; Petroleum prospecting; Risk assessment; Rivers; Surveys, Geothermal Play Fairway Analysis; Geothermal resources; Heat sources; Isotope geochemistry; Potential resources; Potential targets; Reflection seismic; Snake river plains, Geothermal springs https://www.scopus.com/inward/record.uri?eid=2-s2.0-85041048587&partnerID=40&md5=3091e014f108dd57b1a1fb57cfcb8377 cited By 5 J.W. Shervais J.M.G. Glen D.L. Nielson S. Garg L.M. Liberty D. Siler P. Dobson E. Gasperikova E. Sonnenthal G. Neupane J. Deangelo D.L. Newell J.P. Evans N. Snyder article Hofmann201747 Article 2017 10.1016/j.epsl.2017.01.008 Earth and Planetary Science Letters 462 47 – 54 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85010298650&doi=10.1016%2fj.epsl.2017.01.008&partnerID=40&md5=cb26fea0b20d5c80a194da2fd3d53863 Cited by: 12 Axel Hofmann Iain Pitcairn Allan Wilson article Bohnhoff201719 The Marmara section of the North Anatolian Fault Zone (NAFZ) runs under water and is located less than 20 km from the 15-million-person population center of Istanbul in its eastern portion. Based on historical seismicity data, recurrence times forecast an impending magnitude M > 7 earthquake for this region. The permanent GONAF (Geophysical Observatory at the North Anatolian Fault) has been installed around this section to help capture the seismic and strain activity preceding, during, and after such an anticipated event. © Author(s) 2017. 2017 English 18168957 10.5194/sd-22-19-2017 Scientific Drilling 22 Copernicus GmbH 19-28 GFZ German Research Centre for Geosciences, Section 4.2 'Geomechanics and Rheology', Potsdam, 14473, Germany; Free University Berlin, Department of Earth Sciences, Berlin, 12249, Germany; AFAD Disaster and Emergency Management Presidency, Earthquake Department, Ankara, 06510, Turkey; Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokohama, 236-0001, Japan; UNAVCO, Boulder, CO 80301, United States Earthquakes; Geophysics, Historical seismicity; Istanbul; North Anatolian Fault; North Anatolian Fault Zone; Population centers; Recurrence time; Sea of Marmara; Under water, Observatories https://www.scopus.com/inward/record.uri?eid=2-s2.0-85020071261&doi=10.5194%2fsd-22-19-2017&partnerID=40&md5=e4e0d68689713ac4e38dd786936bedf6 cited By 13 M. Bohnhoff G. Dresen U. Ceken F.T. Kadirioglu R.F. Kartal T. Kilic M. Nurlu K. Yanik D. Acarel F. Bulut H. Ito W. Johnson P.E. Malin D. Mencin article Phillips20175789 The San Andreas Fault Observatory at Depth (SAFOD) drilling project directly sampled a transitional (between creeping and locked) segment of the San Andreas Fault at 2.7 km depth. At the site, changes in strain rate occur between periods of coseismic slip (&gt;10−7 s−1) and interseismic creep (10−10 s−1) over decadal scales (~30 years). Microstructural observations of core retrieved from the SAFOD site show throughgoing fractures and gouge-rich cores within the fractures, evidence of predominantly brittle deformation mechanisms. Within the gouge-rich cores, strong phases show evidence of deformation by pressure solution once the grain size is reduced to a critical effective grain size. Models of pressure solution-accommodated creep for quartz-phyllosilicate mixtures indicate that viscous weakening of quartz occurs during the interseismic period once a critical effective grain size of 1 μm is achieved, consistent with microstructural observations. This causes pronounced weakening, as the strength of the mixture is then controlled by the frictional properties of the phyllosilicate phases. These results have pronounced implications for the internal deformation of fault zones in the shallow crust, where at low strain rates, deformation is accommodated by both viscous and brittle deformation mechanisms. As strain rates increase, the critical effective grain size for weakening decreases, localizing deformation into the finest-grained gouges until deformation can no longer be accommodated by viscous processes and purely brittle failure occurs. ©2017. American Geophysical Union. All Rights Reserved. 2017 English 21699313 10.1002/2016JB013828 Journal of Geophysical Research: Solid Earth 122 Blackwell Publishing Ltd 5789-5812 Department of Earth Sciences, University of New Brunswick, Fredericton, NB, Canada; Department of Earth and Planetary Sciences, McGill University, Montréal, QC, Canada 7 brittle deformation; coseismic process; creep; crust; deformation mechanism; fault gouge; grain size; phyllosilicate; pressure; San Andreas Fault; slip; strain rate; strength https://www.scopus.com/inward/record.uri?eid=2-s2.0-85027843395&doi=10.1002%2f2016JB013828&partnerID=40&md5=56028a704278d579d2606b77b09a0d3c cited By 5 N.J. Phillips J.C. White article Tiwari2017795 A high-resolution, optical core scan laboratory has been set up at Borehole Geophysics Research Laboratory (BGRL), Ministry of Earth Sciences (MoES), Karad. The facility provides a DMT® CoreScan3 optical core scanner and digital drill core data management system for core logging and analysis since July 2016. High resolution images are being produced in 360° mode for detailed unwrapped full circumference of drill core or plane mode for top surface image of slabbed drill core. Planar images of fractured cores and cuttings are also obtained. Image resolution ranges from 5 pix/mm (∼16 megapixel equivalent) to 40 pix/mm (∼1024 megapixel equivalent) for mapping of ultra high resolution data. The scanned core images are combined to create a digital core library. The facility helps in core sample analysis, structural analysis, textural and grain-size analysis, geotechnical studies, and integration with geophysical log data. © 2017, Geological Society of India. 2017 English 00167622 10.1007/s12594-017-0793-6 Journal of the Geological Society of India 90 Geological Society of India 795-797 Borehole Geophysics Research Laboratory (BGRL), Ministry of Earth Sciences, Karad, 415 114, India 6 core logging; data management; digital image; grain size; image resolution; mapping; pixel; texture, India; Karad; Maharashtra https://www.scopus.com/inward/record.uri?eid=2-s2.0-85039444255&doi=10.1007%2fs12594-017-0793-6&partnerID=40&md5=dca72002e46ee13ac5a1bdf1a8b1dd8f cited By 3 S. Tiwari S. Mishra G. Srihariprasad D. Vyas A. Warhade D. Nikalje V. Bartakke B. Mahesh P. Tembhurnikar S. Roy article Pati2017722 The Paleoproterozoic Dhala structure with an estimated diameter of ~11 km is a confirmed complex impact structure located in the central Indian state of Madhya Pradesh in predominantly granitic basement (2.65 Ga), in the northwestern part of the Archean Bundelkhand craton. The target lithology is granitic in composition but includes a variety of meta-supracrustal rock types. The impactites and target rocks are overlain by ~1.7 Ga sediments of the Dhala Group and the Vindhyan Supergroup. The area was cored in more than 70 locations and the subsurface lithology shows pseudotachylitic breccia, impact melt breccia, suevite, lithic breccias, and postimpact sediments. Despite extensive erosion, the Dhala structure is well preserved and displays nearly all the diagnostic microscopic shock metamorphic features. This study is aimed at identifying the presence of an impactor component in impact melt rock by analyzing the siderophile element concentrations and rhenium-osmium isotopic compositions of four samples of impactites (three melt breccias and one lithic breccia) and two samples of target rock (a biotite granite and a mafic intrusive rock). The impact melt breccias are of granitic composition. In some samples, the siderophile elements and HREE enrichment observed are comparable to the target rock abundances. The Cr versus Ir concentrations indicate the probable admixture of approximately 0.3 wt.% of an extraterrestrial component to the impact melt breccia. The Re and Os abundances and the 187Os/188Os ratio of 0.133 of one melt breccia specimen confirm the presence of an extraterrestrial component, although the impactor type characterization still remains inconclusive. © The Meteoritical Society, 2017. 2017 10.1111/maps.12826 Meteoritics and Planetary Science 52 722-736 Department of Earth and Planetary Sciences, Nehru Science Centre, University of Allahabad, Allahabad, 211 002, India; National Center of Experimental Mineralogy and Petrology, University of Allahabad, 14 Chatham Lines, Allahabad, 211 002, India; National Research Center for Geoanalysis, 26 Baiwanzhuang Dajie, Xicheng District, Beijing, 100037, China; Department of Lithospheric Research, University of Vienna, Althanstrasse 14, Vienna, A-1090, Austria; Natural History Museum, Burgring 7, Vienna, A-1010, Austria; Museum für Naturkunde – Leibniz Institute for Evolution and Biodiversity Science, Invalidenstrasse 43, Berlin, 10115, Germany; Humboldt-Universität zu Berlin, Unter den Linden 6, Berlin, 10099, Germany; Geochronology Laboratory, University of Brasilia, Brasilia, Brazil 4 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85012996321&doi=10.1111%2fmaps.12826&partnerID=40&md5=248bc8d4f7dd1491af61f26aeaaa18fc cited By 15 J.K. Pati W.J. Qu C. Koeberl W.U. Reimold M. Chakarvorty R.T. Schmitt article Boulton201771 The Alpine Fault in New Zealand is a major plate-bounding structure that typically slips in ∼M8 earthquakes every c. 330 years. To investigate the near-surface, high-velocity frictional behavior of surface- and borehole-derived Alpine Fault gouges and cataclasites, twenty-one rotary shear experiments were conducted at 1 MPa normal stress and 1 m/s equivalent slip velocity under both room-dry and water-saturated (wet) conditions. In the room-dry experiments, the peak friction coefficient (μp = τp/σn) of Alpine Fault cataclasites and fault gouges was consistently high (mean μp = 0.67 ± 0.07). In the wet experiments, the fault gouge peak friction coefficients were lower (mean μp = 0.20 ± 0.12) than the cataclasite peak friction coefficients (mean μp = 0.64 ± 0.04). All fault rocks exhibited very low steady-state friction coefficients (μss) (room-dry experiments mean μss = 0.16 ± 0.05; wet experiments mean μss = 0.09 ± 0.04). Of all the experiments performed, six experiments conducted on wet smectite-bearing principal slip zone (PSZ) fault gouges yielded the lowest peak friction coefficients (μp = 0.10–0.20), the lowest steady-state friction coefficients (μss = 0.03–0.09), and, commonly, the lowest specific fracture energy values (EG = 0.01–0.69 MJ/m2). Microstructures produced during room-dry and wet experiments on a smectite-bearing PSZ fault gouge were compared with microstructures in the same material recovered from the Deep Fault Drilling Project (DFDP-1) drill cores. The near-absence of localized shear bands with a strong crystallographic preferred orientation in the natural samples most resembles microstructures formed during wet experiments. Mechanical data and microstructural observations suggest that Alpine Fault ruptures propagate preferentially through water-saturated smectite-bearing fault gouges that exhibit low peak and steady-state friction coefficients. © 2017 The Authors 2017 English 01918141 10.1016/j.jsg.2017.02.003 Journal of Structural Geology 97 Elsevier Ltd 71-92 Department of Geological Sciences, University of Canterbury, Christchurch, New Zealand; School of Environmental Sciences, University of Liverpool, Liverpool, United Kingdom; State Key Laboratory of Earthquake Dynamics, Institute of Geology, China Earthquake Administration, Beijing, China; School of Geography Environmental and Earth Sciences, Victoria University of Wellington, Wellington, New Zealand; Department of Geology, University of Otago, Dunedin, New Zealand; GNS Science, Lower Hutt, New Zealand Bearings (machine parts); Core drilling; Data flow analysis; Fracture energy; Friction; Infill drilling; Microstructure; Shear bands; Shear flow; Velocity, Alpine Faults; Crystallographic preferred orientations; Friction coefficients; Frictional properties; High-velocity frictions; Micro-structural observations; Microstructural analysis; Rupture propagation, Fault slips, fault; microstructure; rock mechanics; rupture; shear band, Alpine Fault Zone; New Zealand; South Island https://www.scopus.com/inward/record.uri?eid=2-s2.0-85014070983&doi=10.1016%2fj.jsg.2017.02.003&partnerID=40&md5=c9420fca81a504bd11d7332d515ed4bd cited By 35 C. Boulton L. Yao D.R. Faulkner J. Townend V.G. Toy R. Sutherland S. Ma T. Shimamoto article Wang2017216 The Continental Scientific Drilling in the Songliao Basin has been done since 2005, which include the SK1, having finished in 2007, and the SK2 that started drilling in 2014 and is expected to finish in 2017. The purposes of the project are as followings, to drilling through the whole Cretaceous sequence of the Songliao Basin, to obtain continuous high resolution continental geological records by the means of the so-called “2 wells 4 holes drilling procedures”, to research the Cretaceous greenhouse climate changes in order to be better prepared with the challenge caused by the nowadays global warming event. According to the goals above we proposed the rules for the site selection of the SK2 as follows. Firstly, stratigraphic sedimentary records should be continuous. Secondly, sedimentary rocks are preferred, especially the lacustrine fine clastic rocks. Thirdly, thickness of the overburden cap rocks should be as thin as possible. Fourthly, faults should be avoided of. At last, ground conditions should be as good as possible such as roads, electric power, water supply, and so forth. We finally chose the site of SK2 in the Songzhan area where the lacustrine mudstone is well developed in the Xujiaweizi faulted depression of the Songliao Basin. The major target drilling succession is the Lower Cretaceous, namely, Yingcheng, Shahezi, and Huoshiling Formations. The strata under drilling are interbedding sequence of sandstone, siltstone, mudstone and coal, which are intercalated with volcanic rocks and pyroclastic rocks. They are mainly dark rocks of lacustrine facies which reflect the reduced environment. We shall drill through the top boundary (T4) and bottom boundary (T5) of rift fill successions, the boundary between the Upper and Lower Cretaceous, the boundary between Cretaceous and Jurassic (K/J). All these boundaries indicate important geological events which reflect changes of regional tectonics and basin filling styles. With the continuous coring section, we can also obtain some other important geological records with global meanings such as the Cretaceous normal polarity superchron (CNS) and oceanic anoxic event (OAE-1). © 2017, Editorial Office of Earth Science Frontiers. All right reserved. 2017 Chinese 10052321 10.13745/j.esf.2017.01.014 Earth Science Frontiers 24 Science Frontiers editorial department 216-228 College of Earth Sciences, Jilin University, Changchun, 130061, China; Research Institute of Exploration and Development, Daqing Oilfield Company Ltd., Daqing, 163712, China; State Key Laboratory of Biogeology and Environmental Geology, School of Earth Sciences and Resources, China University of Geosciences(Beijing), Beijing, 100083, China; No.1 Geo-logging Company, Daqing Drilling and Exploration Engineering Company, Daqing, 163411, China; Chongqing University of Science & Technology, Chongqing, 401331, China; Research Center of Palaeontology & Stratigraphy, Jilin University, Changchun, 130026, China 1 Climate change; Geology; Global warming; Greenhouses; Rocks; Sedimentology; Site selection; Stratigraphy; Tectonics; Volcanic rocks; Water supply, Continental scientific drillings; Greenhouse climates; Oceanic Anoxic Event; Regional tectonics; Sedimentary records; Sedimentary sequence; Songliao basin; Tithonian to Albian, Sedimentary rocks https://www.scopus.com/inward/record.uri?eid=2-s2.0-85014382176&doi=10.13745%2fj.esf.2017.01.014&partnerID=40&md5=107d188c52121b6731ca89a7a2508277 cited By 24 P. Wang H. Liu Y. Ren X. Wan S. Wang X. Qu Q. Meng Y. Huang Q. Huang Y. Gao C. Wang article Keisling2017136 The Pliocene epoch represents an analog for future climate, with atmospheric carbon dioxide concentrations and continental configurations similar to present. Although the presence of multiple positive feedbacks in polar regions leads to amplified climatic changes, conditions in the Pliocene terrestrial Arctic are poorly characterized. High latitude sedimentary records indicate that dramatic glacial advance and decay occurred in the Pliocene Arctic, with attendant effects on global sea-level. Understanding these deposits and their implications for Earth's future requires developing a sense of climatic evolution across the Pliocene–Pleistocene transition and during the intensification of Northern Hemisphere Glaciation (iNHG) ∼2.7 million yr ago (Ma). Here we reconstruct Arctic terrestrial environmental change from 2.82–2.41 Ma (Marine Isotope Stages (MIS) G10–95) using the distribution of branched glycerol dialkyl glycerol tetraethers (brGDGTs) and the isotopic composition of plant leaf waxes (δDwax) in a sedimentary archive from Lake El'gygytgyn, Northeast Russia. Our records reveal changes in proxy behavior across this interval that we attribute to changing boundary conditions, including sea level, sea ice, vegetation and pCO2 during different MISs. We find that brGDGT temperatures and δDwax are decoupled for most of the record, although both show an increasing range of glacial–interglacial variability following iNHG. δDwax is stable from MIS G10–G4 despite changes in vegetation and temperature, suggesting different sources or pathways for moisture to Lake El'gygytgyn during the Late Pliocene. © 2016 Elsevier B.V. 2017 English 0012821X 10.1016/j.epsl.2016.09.058 Earth and Planetary Science Letters 457 Elsevier B.V. 136-148 Department of Geosciences, University of Massachusetts Amherst, 233 Morrill Science Center, 611 North Pleasant St, Amherst, MA 01002, United States Atmospheric chemistry; Carbon dioxide; Climate change; Glycerol; Isotopes; Lakes; Paraffins; Sea ice; Sea level; Sedimentology; Vegetation, arctic; branched GDGT; Hydrogen isotope; Northern hemisphere glaciations; Palaeoclimate; Pliocene, Glacial geology, alkane; glaciation; hydrogen isotope; hydrological change; Northern Hemisphere; paleoclimate; Pliocene; temperature, Arctic; Chukchi; Elgygytgyn Lake; Russian Federation; Siberia https://www.scopus.com/inward/record.uri?eid=2-s2.0-84995739641&doi=10.1016%2fj.epsl.2016.09.058&partnerID=40&md5=df9aefff5999583d46cc5fb8ca4688ba cited By 13 B.A. Keisling I.S. Castañeda J. Brigham-Grette article wenning_image_2017 Stress-induced borehole deformation analysis in the Collisional Orogeny in the Scandinavian Caledonide deep scientific borehole establishes in situ stress orientation in a poorly characterized region in central Sweden. Two acoustic televiewer logging campaigns, with more than 1 year between campaigns, provide detailed images along the full length of the 2.5 km deep borehole for breakout, drilling-induced tensile fracture (DITF), and natural occurring structural analysis. Borehole breakouts occur in 13 distinct zones along total length of 22 m, indicating an average maximum horizontal stress, SHmax, orientation of 127° ± 12°. Infrequent DITFs are constrained within one zone from 786 to 787 m depth (SHmax orientation: 121° ± 07°). These SHmax orientations are in agreement with the general trend in Scandinavia and are in accordance with many mechanisms that generate crustal stress (e.g., ridge push, topographic loading, and mantel driven stresses). The unique acquisition of image logs in two successions allows for analysis of time-dependent borehole deformation, indicating that six breakout zones have crept, both along the borehole axis and radially around the borehole. Strong dynamic moduli measured on core samples and an inferred weak in situ stress anisotropy inhibit the formation of breakouts and DITFs. Natural fracture orientation below 800 m is congruent to extensional or hybrid brittle shear failure along the same trend as the current SHmax. Analysis of foliation in the image logs reinforces the interpretation that the discontinuous seismic reflectors with fluctuating dip observed in seismic profiles are due to recumbent folding and boudinage. 2017 en 2169-9356 10.1002/2016JB013776 Journal of Geophysical Research: Solid Earth 122 3999--4019 5 breakout growth, elastic properties, foliation and fracture, in situ stress, time dependency https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1002/2016JB013776 \_eprint: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1002/2016JB013776 Quinn C. Wenning Théo Berthet Maria Ask Alba Zappone Jan-Erik Rosberg Bjarne S. G. Almqvist article Neugebauer2017269 Here we report on the first findings of a cryptotephra in the Holocene lacustrine sediment records of the Dead Sea and Tayma palaeolake (NW Arabian Peninsula). The major element glass composition of this rhyolitic tephra is identical to the distal ‘S1’ tephra layer identified in the Yammoûneh palaeolake (Lebanon), in a marine sediment record from the SE Levantine basin and in the Sodmein Cave archaeological site in Egypt. The S1 tephra corresponds to the early Holocene ‘Dikkartın’ dome eruption of the Erciyes Dağ volcano in central Anatolia (Turkey) and has been dated in the marine record at 8830 ± 140 cal yr BP. We present new age estimates of the S1 tephra based on radiocarbon dating of terrestrial plant remains and pollen concentrates revealing ages of 8939 ± 83 cal yr BP in the Dead Sea sediments and 9041 ± 254 cal yr BP in Tayma. The precise date from the Dead Sea allows refining the early Holocene marine reservoir age in the SE Levantine Sea to ca. 320 ± 50 years. Synchronisation of marine and terrestrial palaeoclimate records in the eastern Mediterranean region using the S1 tephra further suggests a time-transgressive expansion of the early Holocene humid period. © 2017 Elsevier Ltd 2017 English 02773791 10.1016/j.quascirev.2017.06.020 Quaternary Science Reviews 170 Elsevier Ltd 269-275 GFZ German Research Centre for Geosciences, Section 5.2 – Climate Dynamics and Landscape Evolution, Telegrafenberg, Potsdam, D-14473, Germany; University of Geneva, Department of Earth Sciences, Rue des Maraichers 13, Geneva, CH-1205, Switzerland; GFZ German Research Centre for Geosciences, Section 5.1 – Geomorphology, Telegrafenberg, Potsdam, D-14473, Germany; Heidelberg University, Institute of Earth Sciences, Im Neuenheimer Feld 234, Heidelberg, D-69120, Germany; GFZ German Research Centre for Geosciences, Section 4.3 – Chemistry and Physics of Earth Materials, Telegrafenberg, Potsdam, D-14473, Germany Plants (botany); Reservoirs (water); Submarine geology, Early Holocene; Eastern Mediterranean; Lake sediments; Marine reservoir age; NW Arabian Peninsula; Palaeoclimate; S1 tephra; Tephrochronology, Sediments, age determination; Holocene; lacustrine deposit; marine environment; marine record; marine sediment; paleoclimate; radiocarbon dating; tephra; tephrochronology; volcano, Anatolia; Arabian Peninsula; Dead Sea; Egypt; Lebanon; Levantine Sea; Mediterranean Region; Mediterranean Sea; Red Sea [(GVR) Egypt]; Saudi Arabia; Sodmein Cave; Tabuk [Saudi Arabia]; Tayma; Turkey https://www.scopus.com/inward/record.uri?eid=2-s2.0-85021281813&doi=10.1016%2fj.quascirev.2017.06.020&partnerID=40&md5=a7615e201a770b5c55e0e84b5c10b5ac cited By 11 I. Neugebauer S. Wulf M.J. Schwab J. Serb B. Plessen O. Appelt A. Brauer article Bussert201713 Microbial life in the continental "deep biosphere" is closely linked to geodynamic processes, yet this interaction is poorly studied. The Cheb Basin in the western Eger Rift (Czech Republic) is an ideal place for such a study because it displays almost permanent seismic activity along active faults with earthquake swarms up to ML 4.5 and intense degassing of mantle-derived CO2 in conduits that show up at the surface in form of mofettes. We hypothesize that microbial life is significantly accelerated in active fault zones and in CO2 conduits, due to increased fluid and substrate flow. To test this hypothesis, pilot hole HJB-1 was drilled in spring 2016 at the major mofette of the Hartoušov mofette field, after extensive pre-drill surveys to optimize the well location. After drilling through a thin caprock-like structure at 78.5 m, a CO2 blowout occurred indicating a CO2 reservoir in the underlying sandy clay. A pumping test revealed the presence of mineral water dominated by Na+, Ca2+, HCO3-, SO42- (Na-Ca-HCO3-SO4 type) having a temperature of 18.6 °C and a conductivity of 6760 μScm-1. The high content of sulfate (1470 mg L-1) is typical of Carlsbad Spa mineral waters. The hole penetrated about 90 m of Cenozoic sediments and reached a final depth of 108.50m in Palaeozoic schists. Core recovery was about 85 %. The cored sediments are mudstones with minor carbonates, sandstones and lignite coals that were deposited in a lacustrine environment. Deformation structures and alteration features are abundant in the core. Ongoing studies will show if they result from the flow of CO2-rich fluids or not. © Author(s) 2017. 2017 English 18168957 10.5194/sd-23-13-2017 Scientific Drilling 23 Copernicus GmbH 13-27 Institute of Applied Geosciences, Technische Universität Berlin, Berlin, 13355, Germany; GFZ German Research Centre for Geosciences, Section 3.2: Organic Geochemistry, Potsdam, 14473, Germany; Institute for Geophysics and Geology, University of Leipzig, Leipzig, 04103, Germany; Leibniz Institute for Applied Geophysics, Hannover, 30655, Germany; GFZ German Research Centre for Geosciences, Section 5.3: Geomicrobiology, Potsdam, 14473, Germany; Balneological Institute, Karlovy Vary, 360 01, Czech Republic Beverages; Calcium; Carbon dioxide; Drilling fluids; Earthquakes; Faulting; Geodynamics; Reservoirs (water); Sodium; Sodium compounds; Sulfur compounds; Water, Cenozoic sediments; Czech Republic; Deformation structure; Earthquake swarms; Geodynamic process; Microbial life; Seismic activity; Well location, Calcium compounds https://www.scopus.com/inward/record.uri?eid=2-s2.0-85036612565&doi=10.5194%2fsd-23-13-2017&partnerID=40&md5=3e475b2abf298cd02f5860e8748eb64e cited By 16 R. Bussert H. Kämpf C. Flechsig K. Hesse T. Nickschick Q. Liu J. Umlauft T. Vylita D. Wagner T. Wonik H.E. Flores M. Alawi article Bücker2017279 Paleolimnological studies require a broad understanding of the geometry and depth of the sedimentary fill of lake basins prior to coring campaigns. Seismic methods are routinely employed for the indirect characterization of lake-bottom sediments. However, the use of seismic methods might occasionally be limited due to surface conditions or poor seismic contrasts between the stratigraphic units, which lead to data quality that is too poor to provide sufficient information for the selection of drill sites. Sources of cultural noise are one of the main reasons why seismic methods fail in study areas near or within large cities, such as Mexico City. Under certain conditions, electrical and electromagnetic methods might be a suitable substitute or complement to seismic exploration, as they respond to different physical properties of the subsurface. To evaluate the applicability of such methods, here we present two recent case studies from the desiccated lakes Chalco and Xochimilco both located in urban areas within the Basin of Mexico where electrical resistivity tomography (ERT), transient electromagnetic (TEM) and magnetotelluric (MT) soundings were conducted for the characterization of lake basement and lacustrine sediments. In both examples, the results of the geophysical exploration contributed valuable stratigraphic information for the following drilling and core recovery, which highlights the potential of electrical and electromagnetic methods in paleolimnological studies. 2017 English 14053322 10.18268/BSGM2017v69n2a1 Boletin de la Sociedad Geologica Mexicana 69 Instituto de Geología, Universidad Nacional Autónoma de México 279-298 Fachbereich Geophysik, Steinmann-Institut, Universität Bonn, Meckenheimer Allee 176, Bonn, 53115, Germany; Forschungsgruppe Geophysik, Department für Geodäsie und Geoinformation, TU-Wien, Gußhausstr. 25-29, Wien, 1040, Austria; Instituto de Geología, Universidad Nacional Autónoma de México, Ciudad Universitaria, Ciudad de México, C.P. 04510, Mexico; Instituto de Geofísica, Universidad Nacional Autónoma de México, Ciudad Universitaria, Ciudad de México, C.P. 04510, Mexico; Departamento de Física, Facultad de Ciencias, Universidad Nacional Autónoma de México, Ciudad Universitaria, Ciudad de México, C.P. 04510, Mexico; Geotem Ingeniería S.A. de C.V., AlheliMz.7 Lt.13-A, Col. Ejidos San Pedro Mártir, Ciudad de México, C.P. 14640, Mexico; Large Lakes Observatory and Department of Earth and Environmental Sciences, University of Minnesota Duluth, 2205 E. 5th St., Research Laboratory Building 207, Duluth, MN 55812, United States; Department of Geology and Environmental Sciences, University of Pittsburgh, 505 SRCC, 4107 O'Hara Street, Pittsburgh, PA 15260, United States; Instituto Pirenaico de Ecología - CSIC, Avda. Montañana 1005, Zaragoza, 50059, Spain; Institut für Geosysteme und Bioindikation, Technische Universität Braunschweig, Langer Kamp 19c, Braunschweig, 38106, Germany; Fachbereich Geophysik, Steinmann-Institut, Universität Bonn, Meckenheimer Allee 176, Bonn, 53115, Germany; Departamento de Sismotectónica y Exploración Geofísica, Gerencia de Estudios de Ingeniería Civil, Comisión Federal de Electricidad, Augusto Rodin 265, Col. Noche Buena, Del. Benito Juarez, Ciudad de México, C.P. 03820, Mexico 2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85028992372&doi=10.18268%2fBSGM2017v69n2a1&partnerID=40&md5=ef8258cf71af43aa8248c9feaffa0fad cited By 9 M. Bücker S.L. García B.O. Guerrero M. Caballero L. Pérez L. Caballero C.P. Paz A. Sánchez-Galindo F.J. Villegas A.F. Orozco E. Brown J. Werne B.V. Garcés A. Schwalb A. Kemna E. Sánchez-Alvaro N. Launizar-Martínez A. Valverde-Placencia F. Garay-Jiménez article Witze2017387 2017 English 00280836 10.1038/nature.2017.22340 Nature 547 Nature Publishing Group 387-388 7664 hot water; mineral; sea water, biosphere; drilling fluid; microbial community; microorganism; pristine environment; project assessment; sea level change; seafloor; seawater; volcanic eruption; volcanic island; volcanic rock, biosphere; biotechnology; contamination; drill; Iceland; island (geological); nuclear waste; organismal interaction; priority journal; rock; sea level; seashore; Short Survey; volcano; animal; bird; ecosystem; history; microbiology; microflora; physiology; plant; sediment, Atlantic Ocean; Atlantic Ocean (North); Heimaey; Iceland; New Zealand; North Island; Surtsey; Taupo; Waikato, Animals; Birds; Ecosystem; Geologic Sediments; History, 20th Century; History, 21st Century; Iceland; Islands; Microbiota; Plants; Volcanic Eruptions https://www.scopus.com/inward/record.uri?eid=2-s2.0-85026351529&doi=10.1038%2fnature.2017.22340&partnerID=40&md5=82c0578e07582c82d5c21220f1fa221e cited By 1 A. Witze article Boulton2017238 Oblique dextral motion on the central Alpine Fault in the last circa 5 Ma has exhumed garnet-oligoclase facies mylonitic fault rocks from ∼35 km depth. During exhumation, deformation, accompanied by fluid infiltration, has generated complex lithological variations in fault-related rocks retrieved during Deep Fault Drilling Project (DFDP-1) drilling at Gaunt Creek, South Island, New Zealand. Lithological, geochemical, and mineralogical results reveal that the fault comprises a core of highly comminuted cataclasites and fault gouges bounded by a damage zone containing cataclasites, protocataclasites, and fractured mylonites. The fault core-alteration zone extends ∼20–30 m from the principal slip zone (PSZ) and is characterized by alteration of primary phases to phyllosilicate minerals. Alteration associated with distinct mineral phases occurred proximal the brittle-to-plastic transition (T ≤ 300–400°C, 6–10 km depth) and at shallow depths (T = 20–150°C, 0–3 km depth). Within the fault core-alteration zone, fractures have been sealed by precipitation of calcite and phyllosilicates. This sealing has decreased fault normal permeability and increased rock mass competency, potentially promoting interseismic strain buildup. © 2016. American Geophysical Union. All Rights Reserved. 2017 English 15252027 10.1002/2016GC006588 Geochemistry, Geophysics, Geosystems 18 Blackwell Publishing Ltd 238-265 Department of Geological Sciences, University of Canterbury, Christchurch, New Zealand; School of Environmental Sciences, University of Liverpool, Liverpool, L69 3GP, United Kingdom; Ocean and Earth Science, National Oceanography Centre Southampton, University of Southampton, Southampton, SO14 3ZH, United Kingdom; Department of Geology, University of Otago, Dunedin, New Zealand; School of Geography, Environment, and Earth Sciences, Victoria University of Wellington, Wellington, New Zealand; GNS Science, Lower Hutt, New Zealand 1 Geochemistry; Lithology; Mechanical permeability; Microstructure; Mineralogy; Minerals; Sealing (finishing); Silicates, Alpine Faults; alteration; Fault rock; New zealand; seismic cycle, Rocks, chemical alteration; deformation; fault zone; geochemistry; lithology; microstructure; neotectonics; permeability; seismicity; slip rate; strain rate, Alpine Fault Zone; New Zealand; South Island https://www.scopus.com/inward/record.uri?eid=2-s2.0-85013250247&doi=10.1002%2f2016GC006588&partnerID=40&md5=e9192b7e21f53bc207fe8b18051569ea cited By 19 C. Boulton C.D. Menzies V.G. Toy J. Townend R. Sutherland article NoAuthor2017vi When this paper was first published online the secondary affiliation for the author Virginia Gail Toy was omitted. The affiliation should have read: Hokkaido University - Earth and Planetary System Science, Department of Natural History Sciences, Graduate School of Sciences, Sapporo, Japan The supplemental data for this paper is also available at http://doi.org/10.5880/ICDP.5052.003. Taylor and Francis apologizes for these errors. © 2017 The Royal Society of New Zealand. 2017 English 00288306 10.1080/00288306.2017.1396882 New Zealand Journal of Geology and Geophysics 60 Taylor and Francis Asia Pacific vi 4 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85032921262&doi=10.1080%2f00288306.2017.1396882&partnerID=40&md5=4528672b64059d3130adbeb71e0b3f72 cited By 0 article Fischer201760 The West Bohemia/Vogtland region is characterized by earthquake swarm activity and degassing of CO2 of mantle origin. A fast increase of CO2 flow rate was observed 4 days after a ML 3.5 earthquake in May 2014 in the Hartoušov mofette, 9 km from the epicentres. During the subsequent 150 days the flow reached sixfold of the original level, and has been slowly decaying until present. Similar behavior was observed during and after the swarm in 2008 pointing to a fault-valve mechanism in long-term. Here, we present the results of simulation of gas flow in a two dimensional model of Earth's crust composed of a sealing layer at the hypocentre depth which is penetrated by the earthquake fault and releases fluid from a relatively low-permeability lower crust. This simple model is capable of explaining the observations, including the short travel time of the flow pulse from 8 km depth to the surface, long-term flow increase and its subsequent slow decay. Our model is consistent with other analyse of the 2014 aftershocks which attributes their anomalous character to exponentially decreasing external fluid force. Our observations and model hence track the fluid pressure pulse from depth where it was responsible for aftershocks triggering to the surface where a significant long-term increase of CO2 flow started 4 days later. © 2016 Elsevier B.V. Article 2017 English 0012821X 10.1016/j.epsl.2016.12.001 Earth and Planetary Science Letters 460 Elsevier B.V. 60 – 67 Bohemia; Czech Republic; Germany; Vogtland; Carbon dioxide; Faulting; Flow of gases; Structural geology; crustal CO2; Earthquake fault; Earthquake swarms; Enhanced permeability; Fault-valve; Fluid pressure pulse; Low permeability; Two dimensional model; carbon dioxide; degassing; earthquake epicenter; earthquake magnitude; earthquake mechanism; earthquake swarm; lower crust; permeability; trigger mechanism; Earthquakes https://www.scopus.com/inward/record.uri?eid=2-s2.0-85006921244&doi=10.1016%2fj.epsl.2016.12.001&partnerID=40&md5=7ae0105dadfa0b007dabd88d5f073f42 Cited by: 39 T. Fischer C. Matyska J. Heinicke article Williams2017151 The Alpine Fault has a <50 m wide geochemically distinct hanging-wall alteration zone. Using a combination of petrological and cathodoluminescence (CL) microscopy, Energy Dispersive Spectroscopy and X-ray diffraction, we document the habitat and mineralising phases of macro- and micro-fractures within the alteration zone using samples derived from outcrop and the Deep Fault Drilling Project. Veins predominantly contain calcite, chlorite, K-feldspar or muscovite. Gouge-filled fractures are also observed and reflect filling from mechanical wear and chlorite mineralisation. CL imaging suggests that each calcite vein was opened and sealed in one episode, possibly corresponding to a single seismic cycle. The thermal stability of mineralising phases and their mutually cross-cutting relationships indicates a cyclic history of fracture opening and mineralisation that extends throughout the seismogenic zone. Cataclasites contain intragranular veins that are hosted within quartzofeldspathic clasts, as well as veins that cross-cut clasts and the surrounding matrix. Intragranular calcite veins formed prior to or during cataclasis. Cross-cutting veins are interpreted to have formed by fracturing of relatively indurated cataclasites after near-surface slip localisation within the Alpine Fault's principal slip zone gouges (PSZs). These observations clearly demonstrate that shear strain is most localised in the shallowest part of the seismogenic zone. © 2017 Elsevier Ltd 2017 English 01918141 10.1016/j.jsg.2017.09.011 Journal of Structural Geology 103 Elsevier Ltd 151-166 Department of Geology, University of Otago, PO Box 56, Dunedin, 9054, New Zealand; School of Environmental Sciences, University of Liverpool, Liverpool, L69 3GP, United Kingdom; School of Geography, Environment, and Earth Sciences, Victoria University of Wellington, PO Box 600, Wellington, 6012, New Zealand Calcite; Earthquakes; Energy dispersive spectroscopy; Fracture; Mica; Seismographs; Seismology; Shear strain; Thermodynamic stability; X ray diffraction, Alpine Faults; Alteration zones; Drilling projects; Fault structure; Fluid-rock interaction; Mineralisation; Seismogenic zones; Surrounding matrix, Mineralogy, cataclasite; fault zone; fracture; mineralization; seismic method; shear strain; slip, Alpine Fault Zone; New Zealand; South Island https://www.scopus.com/inward/record.uri?eid=2-s2.0-85032021352&doi=10.1016%2fj.jsg.2017.09.011&partnerID=40&md5=77a147690a3c4f27e01b3d08bfac27ed cited By 20 J.N. Williams V.G. Toy S.A.F. Smith C. Boulton conference Ogasawara2017237 While mining-induced earthquakes in the deep gold mines of South Africa pose a risk to mines, mineworkers, and the public, they also provide an unusual opportunity to study the physics of earthquakes. The source zone of a M5.5 earthquake that occurred near Orkney, South Africa on 5 August 2014 was well-defined by tens of thousands of aftershocks recorded by instruments deployed as part of a Japanese - South African research project. The upper edge of the M5.5 rupture is located several hundred metres below the mining horizon. A proposal to drill into the M5.5 source zone, as well as several other active faults in other deep mines, was approved by the International Continental scientific Drilling Programme (ICDP) in August 2016. Here we describe the scope and objectives of the project, and the selection and preparation of the principal drilling sites. In addition to the studies of earthquake phenomena, some of the holes will be used by geomicrobiologists to investigate deep microbiological activity fuelled by hydrogen released by seismic rupture to address questions about early life on planet Earth. © 2017 International Society for Rock Mechanics. All Rights Reserved. Conference paper 2017 English 978-192041099-5 ISRM AfriRock - Rock Mechanics for Africa 2017-October International Society for Rock Mechanics 237 – 248 Ritsumeikan University, Kusatsu, Japan; University of the Witwatersrand, Johannesburg, South Africa; Tohoku University, Japan; Institute of Mine Seismology Ltd, South Africa; Council for Geoscience, South Africa; Fukada Geology Institute, Japan; ETH, Switzerland; Seismogen CC, South Africa; Anglogold Ashanti, South Africa; University of New Hampshire, United States; University of Western Australia, Australia; Stanford University, United States; Independent consultant, South Africa; Tel Aviv University, Israel; Princeton University, United States Earth (planet); Earthquakes; Economic geology; Faulting; Gold mines; Rock mechanics; Active fault; African gold mine; Continental scientific drillings; Deep gold mines; Deep-mines; Drilling projects; Microbiological activity; Seismogenic zones; Source zone; South Africa; Infill drilling https://www.scopus.com/inward/record.uri?eid=2-s2.0-85048589628&partnerID=40&md5=d5a56f800a680bc4a854b4dc670d434b Cited by: 7 H. Ogasawara R.J. Durrheim Y. Yabe T. Ito G. Aswegen M. Grobbelaar A. Funato A. Ishida S. Mngadi M.S.D. Manzi M. Ziegler A.K. Ward G. Hofmann P. Moyer M. Boettcher P. Dight W. Ellsworth B. Liebenberg N. Wechsler T. Onstott N. Berset article Liu2017446 This study has examined the potential improvement of the lubricating properties of drilling fluid by adding graphene and graphene oxide (GO). The effects of different concentrations of graphene and GO addition on lubricating properties and friction reduction of drilling fluid have been studied by using an extreme pressure lubrication device and a pin-on-disk tester. In pin-on-disk tests, the pin material was AISI316 steel (casing material) and the disk material was 7075 aluminum alloy (drill pipe material). The pin-on-disk friction and wear tests were carried out under the condition that the pin and disk are immerged in drilling fluid. Results indicated that the lubricating properties of drilling fluid significantly improved by adding appropriate amount of GO materials, while, on the other hand, addition of graphene had limited effect on the lubricating properties of drilling fluid. The lubricating factor of drilling fluid dropped 12.6% by an addition of 0.075 wt% GO. The coefficient of friction between the friction pairs dropped 19.8% by an addition of 0.075 wt% GO. Moreover, the wear volume (WV) of aluminum alloy disc decreased to the minimum value of 0.32 mm3 by an addition of 0.075 wt% GO. On the basis of experimental results, 0.075 wt% GO was added to the oil-based drilling fluids used in an SK-II well, a scientific continental drilling project in the Cretaceous Songliao Basin of Northeast China. Results showed that the lubricating factor of the drilling fluid was reduced by 15.6%, the friction coefficient reduction rate was increased by 24.3% and the aluminum disc wear volume decreased by 20.5%. © 2017 American Scientific Publishers All rights reserved. 2017 English 19414900 10.1166/nnl.2017.2334 Nanoscience and Nanotechnology Letters 9 American Scientific Publishers 446-452 College of Construction Engineering, Jilin University, Changchun, 130061, China; Key Lab of Drilling and Exploitation Technology in Complex Conditions, Ministry of Land and Resources, Changchun, 130061, China; State Key Laboratory of Superhard Materials, Jilin University, Changchun, 130021, China 4 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85019063732&doi=10.1166%2fnnl.2017.2334&partnerID=40&md5=e1d843c0b857c64e06164c9fcee39c69 cited By 18 S.Q. Liu Z.R. Chen Q.N. Meng H.L. Zhou C. Li B.C. Liu article Kontny2017162 The aim of this study was to investigate the effect of meteorite impacts on magnetic properties including magnetic susceptibility and the Verwey transition of Ti-poor titanomagnetite of volcanic rocks from the 3.6 Ma old El’gygytgyn impact structure located in the Okhotsk-Chukotka volcanic belt in north-eastern Russia. The target rocks consist mainly of rhyolite with some andesites, and is a rare example of impact structures within volcanic target rocks on Earth. 27 samples from outside the crater, the crater rim and from the depth interval 316 to 517 m below lake bottom (mblb) of the El’gygytgyn ICDP drilling were studied. A significant decrease of the average specific magnetic susceptibility by around 90% was observed between felsic volcanic rocks from the surface (18.1 × 10-6 m3/kg) and the drill cores from near the crater central uplift (1.9 × 10-6 m3/kg). Ferrimagnetic Fe-Ti oxide assemblages (Verwey transition temperature, TV: -161 to -150°C, Curie temperature, TC: 451 to 581°C), occurring in all studied samples, differ significantly. At the surface titanomaghemite is ubiquitously associated with titanomagnetite. The drill cores lack titanomaghemite, but either show a transformation into titanomagnetite and ilmenite or a strong fragmentation associated with a second TV between -172 and -188°C. Reversible curves of temperature dependence of magnetic susceptibility in the suevite indicate high depositional temperatures of at least 500°C. In the polymict and monomict impact breccia mechanical deformation of titanomagnetite and temperatures of at least 200-350°C related to the shock are suggested from temperature dependent magnetic susceptibility cycling. Lowtemperature oxidation along strongly brecciated grain surfaces in titanomagnetite is suggested to cause the lower TV and we suggest that this phenomenon is related to postimpact hydrothermal activity. The strong magnetic susceptibility decrease at El’gygytgyn is mainly influenced by shock, and post-impact hydrothermalism causes a significant additional depletion. These observations explain why magnetic lows are a ubiquitous phenomenon over impact structures. © 2017, Institute of Geophysics of the ASCR, v.v.i. 2017 English 00393169 10.1007/s11200-016-0819-3 Studia Geophysica et Geodaetica 61 Springer Netherlands 162-183 Institute of Applied Geosciences, Division of Structural Geology, Karlsruhe Institute of Technology, Karlsruhe, Germany 1 impact structure; magnetic susceptibility; meteorite; oxidation; pressure effect; temperature effect; titanomagnetite; volcanic rock, Okhotsk-Chukotka Volcanic Belt; Russian Federation https://www.scopus.com/inward/record.uri?eid=2-s2.0-84994731819&doi=10.1007%2fs11200-016-0819-3&partnerID=40&md5=9b78d3b5833fab125ab79b0a12d7de76 cited By 13 A. Kontny L. Grothaus article Garçon2017216 Knowing the composition, nature and amount of crust at the surface of the early Earth is crucial to understanding the early geodynamics of our planet. Yet our knowledge of the Hadean-Archean crust is far from complete, limited by the poor preservation of Archean terranes, and the fact that less attention has been paid to the sedimentary record that tracks erosion of these ancient remnants. To address this problem and get a more comprehensive view of what an Archean continent may have looked like, we investigated the trace element and Sm-Nd, Lu-Hf isotopic records of Archean metasedimentary rocks from South Africa. We focused our study on sandstone and mudstone from drill core in the Fig Tree Group (3.23–3.26 Ga) of the Barberton granite-greenstone belt, but also analyzed the 3.4 Ga Buck Reef cherts and still older (3.5–3.6 Ga) meta-igneous rocks from the Ancient Gneiss Complex, Swaziland. Based on principal component analysis of major and trace element data, the Fig Tree metasedimentary rocks can be classified into three groups: crustal detritus-rich sediments, Si-rich sediments and Ca-, Fe-rich sediments. The detritus-rich sediments have preserved the Sm-Nd and Lu-Hf isotopic signatures of their continental sources, and hence can be used to constrain the composition of crust eroded in the Barberton area in the Paleoarchean period. Based on Sm/Nd ratios, we estimate that this crust was more mafic than today, with an average SiO2 content of 60.5 ± 2 wt.%. This composition is further supported by isotopic mixing calculations suggesting that the sedimentary source area contained equal proportions of mafic-ultramafic and felsic rocks. This implies that the Archean crust exposed to weathering was more mafic than today but does not exclude a more felsic composition at depth. Neodymium and Hf crustal residence ages show that the eroded crust was, on average, ∼300–400 Ma older than the deposition age of the sediments, which highlights the importance of intracrustal reworking of older crust at ∼3.2 Ga in the Barberton area. The Si-rich sediments have slightly positive εNd (t=3.23Ga) but extremely radiogenic εHf (t=3.23Ga), up to +11. Based on analyses of 3.4 Ga Buck Reef cherts, we suggest that the radiogenic Hf isotopic signature of the Si-rich sediments can be accounted for by the old chert clasts or detrital silicified rock fragments present in the rocks. The latter have extremely high Lu/Hf ratios such that their εHf values would increase dramatically, by about +100 epsilon units every 100 Ma. In the Ca-, Fe-rich sediments, one sample contains carbonate that preserves the typical rare-earth element features of seawater precipitates. The initial Nd isotopic composition of this sample (εNd (t=3.23Ga) = +1.7) is within the range of previous estimates for Archean anoxic seawater. © 2017 Elsevier Ltd Article 2017 English 00167037 10.1016/j.gca.2017.03.006 Geochimica et Cosmochimica Acta 206 Elsevier Ltd 216 – 235 South Africa; Ficus (angiosperm); Archean; chert; continental crust; erosion; hafnium; lutetium; mudstone; neodymium isotope; samarium; sandstone; sedimentary rock https://www.scopus.com/inward/record.uri?eid=2-s2.0-85015881338&doi=10.1016%2fj.gca.2017.03.006&partnerID=40&md5=406ccb7c2f4643597a72cb526a1b79f7 Cited by: 22; All Open Access, Green Open Access M. Garçon R.W. Carlson S.B. Shirey N.T. Arndt M.F. Horan T.D. Mock article Lachmar2017 A 1912-m exploration corehole was drilled along the axis of the eastern Snake River Plain, Idaho. Two temperature logs run on the corehole display an obvious inflection point at about 960 m. Such behavior is indicative of downward fluid flow in the wellbore. The geothermal gradient above 935 m is 4.5 °C/km, while the gradient is 72–75 °C/km from 980 to 1440 m. Projecting the higher gradients upward to where they intersect the lower gradient on the temperature logs places the bottom of the cold, freshwater Snake River Plain aquifer, which suppresses the geothermal gradient at this location, at least 860 m below the surface. The average heat flow for the corehole between 983 and 1550 m is 132 mW/m2. Although the maximum bottom-hole temperature extrapolated from a measured time–temperature curve was only 59.3 °C, geothermometers suggest an equilibrium temperature on the order of 125–140 °C based on a single fluid sample from 1070 m. Furthermore, below 960 m the basalt core shows obvious signs of alteration, including a distinct color change, the formation of smectite clay, and the presence of secondary minerals filling vesicles and fracture zones. This alteration boundary could act as an effective cap or seal for a hot-water geothermal system. © 2017, The Author(s). 2017 English 21959706 10.1186/s40517-017-0086-8 Geothermal Energy 5 SpringerOpen Department of Geology, Utah State University, Logan, UT 84322-4505, United States; Department of Earth Sciences, Syracuse University, Syracuse, NY 13244, United States; Department of Earth Science & Geography, Vassar College, Poughkeepsie, NY 12604, United States; Department of Earth Sciences, Southern Methodist University, Dallas, TX 75275-0395, United States; DOSECC Exploration Services, LLC, 2075 Pioneer Road, Salt Lake City, UT 84104, United States 1 Aquifers; Basalt; Clay alteration; Flow of fluids; Geothermal fields; Geothermal logging; Rivers; Water; X ray diffraction, Bottom hole temperatures; Corehole; Equilibrium temperatures; Freshwater aquifer; Geothermal gradients; Geothermal potential; Geothermometers; Temperature log, Thermal logging, aquifer; basalt; geothermal system; geothermometry; heat flow; temperature gradient; thermal alteration; X-ray diffraction, Idaho; Snake River Plain; United States, Calluna vulgaris https://www.scopus.com/inward/record.uri?eid=2-s2.0-85038103911&doi=10.1186%2fs40517-017-0086-8&partnerID=40&md5=bd74d4c9eef37ed62bf07cab26bfe4e9 cited By 5 T.E. Lachmar T.G. Freeman C.J. Sant J.R. Walker J.F. Batir J.W. Shervais J.P. Evans D.L. Nielson D.D. Blackwell article DasGupta201751 The ∼1.88 km diameter Lonar impact crater formed ∼570 ka ago and is an almost circular depression hosted entirely in the Poladpur suite of the ∼65 Ma old basalts of the Deccan Traps. To understand the effects of impact cratering on basaltic targets, commonly found on the surfaces of inner Solar System planetary bodies, major and trace element concentrations as well as Nd and Sr isotopic compositions were determined on a suite of selected samples composed of: basalts, a red bole sample, which is a product of basalt alteration, impact breccia, and impact glasses, either in the form of spherules (&lt;1 mm in diameter) or non-spherical impact glasses (&gt;1 mm and &lt;1 cm). These data include the first highly siderophile element (HSE) concentrations for the Lonar spherules. The chemical index of alteration (CIA) values for the basalts and impact breccia (36.4–42.7) are low while the red bole sample shows a high CIA value (55.6 in the acid-leached sample), consistent with its origin by aqueous alteration of the basalts. The Lonar spherules are classified into two main groups based on their CIA values. Most spherules show low CIA values (Group 1: 34.7–40.5) overlapping with the basalts and impact breccia, while seven spherules show significantly higher CIA values (Group 2: &gt;43.0). The Group 1 spherules are further subdivided into Groups 1a and 1b, with Group 1a spherules showing higher Ni and mostly higher Cr compared to the Group 1b spherules. Iridium and Cr concentrations of the spherules are consistent with the admixture of 1–8 wt% of a chondritic impactor to the basaltic target rocks. The impactor contribution is most prominent in the Group 1a and Group 2 spherules, which show higher Ni/Co, Ni/Cr and Cr/Co ratios compared to the target basalts. In contrast, the Group 1b spherules show major and trace element compositions that overlap with those of the impact breccia and are characterized by high EFTh (Enrichment Factor for Th defined as the Nb-normalized concentration of Th relative to that of the average basalt) as well as fractionated La/Sm(N), and higher large ion lithophile element (LILE) concentrations compared to the basalts. The relatively more radiogenic Sr and less radiogenic Nd isotopic composition of the impact breccia and non-spherical impact glasses compared to the target basalts are consistent with melting and mixing of the Precambrian basement beneath the Deccan basalt with up to 15 wt% contribution of the basement to these samples. Variations in the moderately siderophile element (MSE) concentration ratios of the impact breccia as well as all the spherules are best explained by contributions from three components – a chondritic impactor, the basaltic target rocks at Lonar and the basement underlying the Deccan basalts. The large variations in concentrations of volatile elements like Zn and Cu and correlated variations of EFCu-EFZn, EFPb-EFZn, EFK-EFZn and EFNa-EFZn, particularly in the Group 1a spherules, are best explained by evaporation-condensation effects during impact. While most spherules, irrespective of their general major and trace element composition, show a loss in volatile elements (e.g., Zn and Cu) relative to the target basalts, some spherules, mainly of Group 1, display enrichments in these elements that are interpreted to reflect the unique preservation of volatile-rich vapour condensates resulting from geochemical fractionation in a vertical direction within the vapour cloud. © 2017 Elsevier Ltd 2017 10.1016/j.gca.2017.07.022 Geochimica et Cosmochimica Acta 215 51-75 Centre for Earth Sciences, Indian Institute of Science, Bangalore, 560012, India; Vrije Universiteit Brussel, Analytical-, Environmental- & Geo-Chemistry, Pleinlaan 2, Brussels, 1050, Belgium; Ghent University, Department of Analytical Chemistry, Campus Sterre, Krijgslaan, 281 – S12, Ghent, 9000, Belgium https://www.scopus.com/inward/record.uri?eid=2-s2.0-85026498285&doi=10.1016%2fj.gca.2017.07.022&partnerID=40&md5=7153de6833c6a68026675473f838e2f9 cited By 13 R. Das Gupta A. Banerjee S. Goderis P. Claeys F. Vanhaecke R. Chakrabarti article Xu20171 Continental scientific drilling can be regarded as "a telescope into the Earth's interior" because it provides process insight and uncompromised samples of rocks, fluids, and even sampled from the deep biosphere from the Earth's surface to great depths. As one of the three founding members of the International Continental Scientific Drilling Program (ICDP), ICDP China has made great achievements in many scientific drilling-related research fields. Based on the ICDP participation it attracted global attention of scientists and set up not only the Chinese Continental Scientific Drilling (CCSD) Program in 2001 but also a growing number of ambitious drilling projects in the country. The 5158m deep borehole of the CCSD project at Donghai County in the Sulu ultrahigh-pressure metamorphic terrain demonstrates that large amounts of crustal rocks of the South China Block have been subducted to at least 120 km, followed by rapid uplift. After successful completion of drilling at Donghai, several continental scientific drilling projects were conducted with funding of the Chinese government and partially with support of ICDP, resulting in a total drilling depth of more than 35 000 m. These projects encompass the Continental Environmental Scientific Drilling Program of China, the Scientific Drilling Project of Wenchuan Earthquake Fault Zone, the Continental Scientific Drilling Project of Cretaceous Songliao Basin, and the Program of Selected Continental Scientific Drilling and Experiments. On the occasion of the 20th anniversary of the ICDP and the 15th anniversary of the CCSD Program, this paper reviews the history and major progress of the CCSD Program. © Author(s) 2017. 2017 English 18168957 10.5194/sd-22-1-2017 Scientific Drilling 22 Copernicus GmbH 1-18 State Key Laboratory for Mineral Deposits Research, School of Earth Sciences and Engineering, Nanjing University, Nanjing, 210023, China; Laboratory for Continental Tectonics and Dynamics, Institute of Geology, Chinese Academy of Geological Sciences, Beijing, 100037, China; School of Earth Sciences and Resources, China University of Geosciences, Beijing, 100083, China; State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, 710061, China Earthquakes; Metamorphic rocks, Chinese Government; Continental scientific drillings; Drilling projects; Earth's interior; Scientific drilling; South China block; Ultrahigh-pressure metamorphic; Wenchuan Earthquake, Drilling fluids https://www.scopus.com/inward/record.uri?eid=2-s2.0-85020083040&doi=10.5194%2fsd-22-1-2017&partnerID=40&md5=d36b862aef8b48651b4d04158f792ecf cited By 2 Z. Xu J. Yang C. Wang Z. An H. Li Q. Wang D. Su article Sutherland2017137 Temperature and fluid pressure conditions control rock deformation and mineralization on geological faults, and hence the distribution of earthquakes. Typical intraplate continental crust has hydrostatic fluid pressure and a near-surface thermal gradient of 31 ± 15 degrees Celsius per kilometre. At temperatures above 300-450 degrees Celsius, usually found at depths greater than 10-15 kilometres, the intra-crystalline plasticity of quartz and feldspar relieves stress by aseismic creep and earthquakes are infrequent. Hydrothermal conditions control the stability of mineral phases and hence frictional-mechanical processes associated with earthquake rupture cycles, but there are few temperature and fluid pressure data from active plate-bounding faults. Here we report results from a borehole drilled into the upper part of the Alpine Fault, which is late in its cycle of stress accumulation and expected to rupture in a magnitude 8 earthquake in the coming decades. The borehole (depth 893 metres) revealed a pore fluid pressure gradient exceeding 9 ± 1 per cent above hydrostatic levels and an average geothermal gradient of 125 ± 55 degrees Celsius per kilometre within the hanging wall of the fault. These extreme hydrothermal conditions result from rapid fault movement, which transports rock and heat from depth, and topographically driven fluid movement that concentrates heat into valleys. Shear heating may occur within the fault but is not required to explain our observations. Our data and models show that highly anomalous fluid pressure and temperature gradients in the upper part of the seismogenic zone can be created by positive feedbacks between processes of fault slip, rock fracturing and alteration, and landscape development at plate-bounding faults. © 2017 Macmillan Publishers Limited, part of Springer Nature. All rights reserved. 2017 English 00280836 10.1038/nature22355 Nature 546 Nature Publishing Group 137-140 GNS Science, PO Box 30368, Lower Hutt, New Zealand; SGEES, Victoria University of Wellington, PO Box 600, Wellington, New Zealand; Department of Geology, University of Otago, PO Box 56, Dunedin, 9054, New Zealand; Department of Ocean and Earth Science, University of Southampton, Southampton, SO14 3ZH, United Kingdom; School of Environmental Sciences, University of Liverpool, Liverpool, L69 3GP, United Kingdom; Department of Earth Sciences, University of California, Riverside, CA 92521, United States; Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI 48109, United States; University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand; School of Geology and Geophysics, University of Oklahoma, Norman, OK 73019, United States; CNRS, Université de Montpellier, Montpellier, 34095, France; GNS Science, Private Bag 1930, Dunedin, 9054, New Zealand; Universit Grenoble-Alpes, Universit Savoie Mont Blanc, CNRS, IRD, IFSTTAR, ISTerre, Grenoble, F-38000, France; Schlumberger Fiber-Optic Technology Centre, Romsey, Hampshire, SO51 9DL, United Kingdom; Department of Geoscience, University of Wisconsin-Madison, Madison, WI 53706, United States; Department of Earth and Space Science, Osaka University, Osaka, 565-0871, Japan; Department of Geosphere Sciences, Yamaguchi University, Yamaguchi, 753-8511, Japan; Graduate School of Engineering, Kyoto University, Kyoto, 615-8540, Japan; Kochi Institute for Core Sample Research, Japan Agency for Marine-Earth Science and Technology, Kochi, 783-8502, Japan; Department of Physics, University of Alberta, Edmonton, AB T6G 2R3, Canada; Department of Earth and Planetary Sciences, McGill University, Montreal, QC H3A 0G4, Canada; Department of Earth and Planetary Sciences, Macquarie University, Sydney, NSW 2109, Australia; ScopeM, ETH, Zürich, 8093, Switzerland; Department of Geology, Shinshu University, Asahi 3-1-1, Matsumoto, Japan; Faculty of Geosciences, HPT Laboratory, Utrecht University, Utrecht, 3584 CD, Netherlands; Department of Earth Science and Technology, Akita University, Akita City, 010-8502, Japan; GFZ German Research Centre for Geosciences, Telegrafenberg, Potsdam, 14473, Germany; Geological Survey of Japan, AIST, Tsukuba, Japan; Department of Geosciences, Pennsylvania State University, University Park, PA 16802, United States 7656 active fault; deformation; earthquake magnitude; earthquake rupture; fluid dynamics; heating; hydrostatic pressure; hydrothermal activity; hydrothermal system; movement; plate boundary; pressure effect; seismic zone; temperature effect; temperature gradient; topography, Article; earthquake; environmental temperature; heat; heating; hydrostatic pressure; pressure gradient; priority journal; rock; shear stress; topography https://www.scopus.com/inward/record.uri?eid=2-s2.0-85020188195&doi=10.1038%2fnature22355&partnerID=40&md5=c62982ed0f3b74e83c993a796fbeea43 cited By 75 P. Upton J. Coussens M. Allen L.-M. Baratin N. Barth L. Becroft A. Boles N.G.R. Broderick L. Janku-Capova B.M. Carpenter B. Célérier A. Cooper A. Coutts L. Craw M.-L. Doan J. Eccles D. Faulkner J. Grieve J. Grochowski A. Gulley A. Hartog K. Jacobs T. Jeppson N. Kato S. Keys Y. Kometani W. Lin A. Lukacs D. Mallyon C. Massiot L. Mathewson B. Melosh C. Menzies J. Moore L. Morales C. Morgan H. Mori A. Niemeijer O. Nishikawa D. Prior M. Savage A. Schleicher N. Shigematsu S. Taylor-Offord D. Teagle H. Tobin R. Valdez K. Weaver T. Wiersberg N. Woodman M. Zimmer article Engelhardt2017144 Volcaniclastic fall deposits in ICDP drilling cores from Lake Van, Turkey, contain sodium-rich sanidine and calcium-rich anorthoclase, which both comprise a variety of textural zoning and inclusions. An age model records the lake's history and is based on climate-stratigraphic correlations, tephrostratigraphy, paleomagnetics, and earlier 40Ar/39Ar analyses (Stockhecke et al., 2014b). Results from total fusion and stepwise heating 40Ar/39Ar analyses presented in this study allow for the comparison of radiometric constraints from texturally diversified feldspar and the multi-proxy lacustrine age model and vice versa. This study has investigated several grain-size fractions of feldspar from 13 volcaniclastic units. The feldspars show textural features that are visible in cathodoluminescence (CL) or back-scattered electron (BSE) images and can be subdivided into three dominant zoning-types: (1) compositional zoning, (2) round pseudo-oscillatory zoning and (3) resorbed and patchy zoning (Ginibre et al., 2004). Round pseudo-oscillatory zoning records a sensitive alternation of Fe and Ca that also reflects resorption processes. This is only visible in CL images. Compositional zoning reflects anticorrelated anorthite and orthoclase contents and is visible in BSE. Eleven inverse isochron ages from total fusion and three from stepwise heating analyses fit the age model. Four experiments resulted in older inverse isochron ages that do not concur with the model within 2σ uncertainties and that deviate from 1 ka to 17 ka minimum. C- and R-type zoning are interpreted as representing growth in magma chamber cupolas, as wall mushes, or in narrow conduits. Persistent compositions of PO-type crystals and abundant surfaces recording dissolution features correspond to formation within a magma chamber. C-type zoning and R-type zoning have revealed an irregular incorporation of melt and fluid inclusions. These two types of zoning in feldspar are interpreted as preferentially contributing either heterogeneously distributed excess 40Ar or inherited 40Ar to the deviating 40Ar/39Ar ages that are discussed in this study. © 2017 Elsevier Ltd 2017 English 00167037 10.1016/j.gca.2017.07.039 Geochimica et Cosmochimica Acta 217 Elsevier Ltd 144-170 Institut für Erd- und Umweltwissenschaften, Universität Potsdam, Karl-Liebknecht-Str. 24-25, Potsdam, 14476, Germany; Large Lakes Observatory, University of Minnesota, 2205 E. 5th Street, Duluth, MN 55812-3024, United States argon-argon dating; feldspar; grain size; lacustrine deposit; radiocarbon dating; sediment core; volcaniclastic deposit, Lake Van; Turkey https://www.scopus.com/inward/record.uri?eid=2-s2.0-85028721559&doi=10.1016%2fj.gca.2017.07.039&partnerID=40&md5=62261f60f0c4fdaf5cc4d207996ab4a8 cited By 4 J.F. Engelhardt M. Sudo M. Stockhecke R. Oberhänsli article Xu20171 Continental scientific drilling can be regarded as "a telescope into the Earth's interior" because it provides process insight and uncompromised samples of rocks, fluids, and even sampled from the deep biosphere from the Earth's surface to great depths. As one of the three founding members of the International Continental Scientific Drilling Program (ICDP), ICDP China has made great achievements in many scientific drilling-related research fields. Based on the ICDP participation it attracted global attention of scientists and set up not only the Chinese Continental Scientific Drilling (CCSD) Program in 2001 but also a growing number of ambitious drilling projects in the country. The 5158m deep borehole of the CCSD project at Donghai County in the Sulu ultrahigh-pressure metamorphic terrain demonstrates that large amounts of crustal rocks of the South China Block have been subducted to at least 120 km, followed by rapid uplift. After successful completion of drilling at Donghai, several continental scientific drilling projects were conducted with funding of the Chinese government and partially with support of ICDP, resulting in a total drilling depth of more than 35 000 m. These projects encompass the Continental Environmental Scientific Drilling Program of China, the Scientific Drilling Project of Wenchuan Earthquake Fault Zone, the Continental Scientific Drilling Project of Cretaceous Songliao Basin, and the Program of Selected Continental Scientific Drilling and Experiments. On the occasion of the 20th anniversary of the ICDP and the 15th anniversary of the CCSD Program, this paper reviews the history and major progress of the CCSD Program. © Author(s) 2017. Article 2017 English 18168957 10.5194/sd-22-1-2017 Scientific Drilling 22 Copernicus GmbH 1 – 18 Earthquakes; Metamorphic rocks; Chinese Government; Continental scientific drillings; Drilling projects; Earth's interior; Scientific drilling; South China block; Ultrahigh-pressure metamorphic; Wenchuan Earthquake; Drilling fluids https://www.scopus.com/inward/record.uri?eid=2-s2.0-85020083040&doi=10.5194%2fsd-22-1-2017&partnerID=40&md5=d36b862aef8b48651b4d04158f792ecf Cited by: 2; All Open Access, Gold Open Access, Green Open Access Zhiqin Xu Jingsui Yang Chengshan Wang ZhiSheng An Haibing Li Qin Wang Dechen Su article Xu20171 Continental scientific drilling can be regarded as "a telescope into the Earth's interior" because it provides process insight and uncompromised samples of rocks, fluids, and even sampled from the deep biosphere from the Earth's surface to great depths. As one of the three founding members of the International Continental Scientific Drilling Program (ICDP), ICDP China has made great achievements in many scientific drilling-related research fields. Based on the ICDP participation it attracted global attention of scientists and set up not only the Chinese Continental Scientific Drilling (CCSD) Program in 2001 but also a growing number of ambitious drilling projects in the country. The 5158m deep borehole of the CCSD project at Donghai County in the Sulu ultrahigh-pressure metamorphic terrain demonstrates that large amounts of crustal rocks of the South China Block have been subducted to at least 120 km, followed by rapid uplift. After successful completion of drilling at Donghai, several continental scientific drilling projects were conducted with funding of the Chinese government and partially with support of ICDP, resulting in a total drilling depth of more than 35 000 m. These projects encompass the Continental Environmental Scientific Drilling Program of China, the Scientific Drilling Project of Wenchuan Earthquake Fault Zone, the Continental Scientific Drilling Project of Cretaceous Songliao Basin, and the Program of Selected Continental Scientific Drilling and Experiments. On the occasion of the 20th anniversary of the ICDP and the 15th anniversary of the CCSD Program, this paper reviews the history and major progress of the CCSD Program. © Author(s) 2017. 2017 English 18168957 10.5194/sd-22-1-2017 Scientific Drilling 22 Copernicus GmbH 1-18 State Key Laboratory for Mineral Deposits Research, School of Earth Sciences and Engineering, Nanjing University, Nanjing, 210023, China; Laboratory for Continental Tectonics and Dynamics, Institute of Geology, Chinese Academy of Geological Sciences, Beijing, 100037, China; School of Earth Sciences and Resources, China University of Geosciences, Beijing, 100083, China; State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, 710061, China Earthquakes; Metamorphic rocks, Chinese Government; Continental scientific drillings; Drilling projects; Earth's interior; Scientific drilling; South China block; Ultrahigh-pressure metamorphic; Wenchuan Earthquake, Drilling fluids https://www.scopus.com/inward/record.uri?eid=2-s2.0-85020083040&doi=10.5194%2fsd-22-1-2017&partnerID=40&md5=d36b862aef8b48651b4d04158f792ecf cited By 2 Z. Xu J. Yang C. Wang Z. An H. Li Q. Wang D. Su article Sutherland2017137 Temperature and fluid pressure conditions control rock deformation and mineralization on geological faults, and hence the distribution of earthquakes. Typical intraplate continental crust has hydrostatic fluid pressure and a near-surface thermal gradient of 31 ± 15 degrees Celsius per kilometre. At temperatures above 300-450 degrees Celsius, usually found at depths greater than 10-15 kilometres, the intra-crystalline plasticity of quartz and feldspar relieves stress by aseismic creep and earthquakes are infrequent. Hydrothermal conditions control the stability of mineral phases and hence frictional-mechanical processes associated with earthquake rupture cycles, but there are few temperature and fluid pressure data from active plate-bounding faults. Here we report results from a borehole drilled into the upper part of the Alpine Fault, which is late in its cycle of stress accumulation and expected to rupture in a magnitude 8 earthquake in the coming decades. The borehole (depth 893 metres) revealed a pore fluid pressure gradient exceeding 9 ± 1 per cent above hydrostatic levels and an average geothermal gradient of 125 ± 55 degrees Celsius per kilometre within the hanging wall of the fault. These extreme hydrothermal conditions result from rapid fault movement, which transports rock and heat from depth, and topographically driven fluid movement that concentrates heat into valleys. Shear heating may occur within the fault but is not required to explain our observations. Our data and models show that highly anomalous fluid pressure and temperature gradients in the upper part of the seismogenic zone can be created by positive feedbacks between processes of fault slip, rock fracturing and alteration, and landscape development at plate-bounding faults. © 2017 Macmillan Publishers Limited, part of Springer Nature. All rights reserved. 2017 English 00280836 10.1038/nature22355 Nature 546 Nature Publishing Group 137-140 GNS Science, PO Box 30368, Lower Hutt, New Zealand; SGEES, Victoria University of Wellington, PO Box 600, Wellington, New Zealand; Department of Geology, University of Otago, PO Box 56, Dunedin, 9054, New Zealand; Department of Ocean and Earth Science, University of Southampton, Southampton, SO14 3ZH, United Kingdom; School of Environmental Sciences, University of Liverpool, Liverpool, L69 3GP, United Kingdom; Department of Earth Sciences, University of California, Riverside, CA 92521, United States; Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI 48109, United States; University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand; School of Geology and Geophysics, University of Oklahoma, Norman, OK 73019, United States; CNRS, Université de Montpellier, Montpellier, 34095, France; GNS Science, Private Bag 1930, Dunedin, 9054, New Zealand; Universit Grenoble-Alpes, Universit Savoie Mont Blanc, CNRS, IRD, IFSTTAR, ISTerre, Grenoble, F-38000, France; Schlumberger Fiber-Optic Technology Centre, Romsey, Hampshire, SO51 9DL, United Kingdom; Department of Geoscience, University of Wisconsin-Madison, Madison, WI 53706, United States; Department of Earth and Space Science, Osaka University, Osaka, 565-0871, Japan; Department of Geosphere Sciences, Yamaguchi University, Yamaguchi, 753-8511, Japan; Graduate School of Engineering, Kyoto University, Kyoto, 615-8540, Japan; Kochi Institute for Core Sample Research, Japan Agency for Marine-Earth Science and Technology, Kochi, 783-8502, Japan; Department of Physics, University of Alberta, Edmonton, AB T6G 2R3, Canada; Department of Earth and Planetary Sciences, McGill University, Montreal, QC H3A 0G4, Canada; Department of Earth and Planetary Sciences, Macquarie University, Sydney, NSW 2109, Australia; ScopeM, ETH, Zürich, 8093, Switzerland; Department of Geology, Shinshu University, Asahi 3-1-1, Matsumoto, Japan; Faculty of Geosciences, HPT Laboratory, Utrecht University, Utrecht, 3584 CD, Netherlands; Department of Earth Science and Technology, Akita University, Akita City, 010-8502, Japan; GFZ German Research Centre for Geosciences, Telegrafenberg, Potsdam, 14473, Germany; Geological Survey of Japan, AIST, Tsukuba, Japan; Department of Geosciences, Pennsylvania State University, University Park, PA 16802, United States 7656 active fault; deformation; earthquake magnitude; earthquake rupture; fluid dynamics; heating; hydrostatic pressure; hydrothermal activity; hydrothermal system; movement; plate boundary; pressure effect; seismic zone; temperature effect; temperature gradient; topography, Article; earthquake; environmental temperature; heat; heating; hydrostatic pressure; pressure gradient; priority journal; rock; shear stress; topography https://www.scopus.com/inward/record.uri?eid=2-s2.0-85020188195&doi=10.1038%2fnature22355&partnerID=40&md5=c62982ed0f3b74e83c993a796fbeea43 cited By 75 R. Sutherland J. Townend V. Toy P. Upton J. Coussens M. Allen L.-M. Baratin N. Barth L. Becroft C. Boese A. Boles C. Boulton N.G.R. Broderick L. Janku-Capova B.M. Carpenter B. Célérier C. Chamberlain A. Cooper A. Coutts S. Cox L. Craw M.-L. Doan J. Eccles D. Faulkner J. Grieve J. Grochowski A. Gulley A. Hartog J. Howarth K. Jacobs T. Jeppson N. Kato S. Keys M. Kirilova Y. Kometani R. Langridge W. Lin T. Little A. Lukacs D. Mallyon E. Mariani C. Massiot L. Mathewson B. Melosh C. Menzies J. Moore L. Morales C. Morgan H. Mori A. Niemeijer O. Nishikawa D. Prior K. Sauer M. Savage A. Schleicher D.R. Schmitt N. Shigematsu S. Taylor-Offord D. Teagle H. Tobin R. Valdez K. Weaver T. Wiersberg J. Williams N. Woodman M. Zimmer article Doughty2017501 Article 2017 10.1007/s10040-016-1497-5 Hydrogeology Journal 25 501 – 517 2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85000443571&doi=10.1007%2fs10040-016-1497-5&partnerID=40&md5=f751598f66a12c91f8d3914ab489f27c Cited by: 10; All Open Access Christine Doughty Chin-Fu Tsang Jan-Erik Rosberg Christopher Juhlin Patrick F. Dobson Jens T. Birkholzer article 10.1130/B31357.1 {Thick sequences of salt (halite) have been recovered in a 456-m-long core drilled at the deepest floor of the Dead Sea by the Dead Sea Deep Drilling Project and extending ∼200 k.y. back in time. The salt sequences were precipitated in the ancient lake that occupied the Dead Sea Basin during the last three interglacials during intervals of extreme aridity in the lake’s watershed. The salt layers alternate with “mud” layers that indicate wetter periods in the watershed, when floods transported fine detritus matter to the lake. The salt sources include brine discharge and freshwater runoff that dissolved halite units. Dissolved salts accumulated in the lake during glacials and relatively wet periods when the lake expanded, and precipitated during interglacials when the lake levels dropped.This study establishes for the first time the evaporite facies and sedimentological features of the deep Dead Sea brine during interglacial periods, by using the modern precipitation of halite in the Dead Sea as an analogue for past halite depositional periods as recorded in the drill core. The halite intervals provide a record of facies characterizing a deep-water evaporitic environment. The halite layers consist mainly of two types of crystals: small cumulate crystals containing halite rafts, which indicate precipitation from the surface brine of the lake (epilimnion), and bottom-growth (usually large) halite crystals that precipitated on the lake floor (hypolimnion). The layers of small halite crystals formed during drier periods as compared to the bottom-growth crystals. The bottom-growth halite crystals contain variable quantities of detritus and show mild dissolution structures at the contact between the mud and the halite crystals. These two main types of halite, in combination with “muds” and gypsum, comprise seven categories of salt facies that reflect the hydrological conditions (dry-to-wet), and that display a cyclic (decadal to millennial) pattern along the sampled core intervals. Frequent alternation of these two salt crystal types suggests seasonal changes, whereby the small cumulate crystals were formed during the summer, and the bottom-growth crystals were formed during the winter, when the surface temperatures of the lake were low, and the surface water was less saline and less likely to be saturated with respect to halite. Comparison of the last interglacial halite with the modern halite facies, together with the absence of significant dissolution features within the halite and the cyclic nature of the facies, indicates that the lake was continuously deep (&gt;100 m) during the last 200 k.y.} 2016 05 0016-7606 10.1130/B31357.1 GSA Bulletin 128 824-841 5-6 https://doi.org/10.1130/B31357.1 Yael Kiro Steven L. Goldstein Boaz Lazar Mordechai Stein article Kring2016 The Schrödinger basin on the lunar farside is â ;1/4320 km in diameter and the best-preserved peak-ring basin of its size in the Earth-Moon system. Here we present spectral and photogeologic analyses of data from the Moon Mineralogy Mapper instrument on the Chandrayaan-1 spacecraft and the Lunar Reconnaissance Orbiter Camera (LROC) on the LRO spacecraft, which indicates the peak ring is composed of anorthositic, noritic and troctolitic lithologies that were juxtaposed by several cross-cutting faults during peak-ring formation. Hydrocode simulations indicate the lithologies were uplifted from depths up to 30 km, representing the crust of the lunar farside. Through combining geological and remote-sensing observations with numerical modelling, we show that a Displaced Structural Uplift model is best for peak rings, including that in the K-T Chicxulub impact crater on Earth. These results may help guide sample selection in lunar sample return missions that are being studied for the multi-Agency International Space Exploration Coordination Group. © The Author(s) 2016. 2016 10.1038/ncomms13161 Nature Communications 7 Center for Lunar Science and Exploration, Lunar and Planetary Institute, Universities Space Research Association, 3600 Bay Area Boulevard, Houston, TX 77058, United States; Impacts and Astromaterials Research Centre, Department of Earth Science and Engineering, Imperial College London, London, SW7 2AZ, United Kingdom; Department of Geosciences, University of Alaska, Fairbanks, AK 99775, United States; Department of Earth, Environmental and Planetary Sciences, Brown University Providence, Rhode Island, 02912, United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-84992437254&doi=10.1038%2fncomms13161&partnerID=40&md5=5032a69faec571de4d14ff16f9f84282 cited By 33 D.A. Kring G.Y. Kramer G.S. Collins R.W.K. Potter M. Chandnani article joosu2016petrography 2016 Geochimica et Cosmochimica Acta 186 Elsevier 135--153 Lauri Joosu Aivo Lepland Timmu Kreitsmann Kärt Üpraus Nick MW Roberts Päärn Paiste Adam P Martin Kalle Kirsimäe article Farber2016639 The 3.33 to 3.26 Ga Mendon Formation in the Palaeoarchaean Barberton greenstone belt, South Africa, forms the uppermost unit of the Onverwacht Group. It is dominated by ultramafic volcanic rocks interbedded with thin layers of cherty sediments that show pervasive alteration, including widespread serpentinisation, silicification and chert and quartz veining. The BARB4 drill core of the ICDP Barberton drilling project exposes a unique section through the Mendon Formation in the Manzimnyama Syncline. The komatiites are pervasively altered to an assemblage comprising quartz, chlorite, carbonate, talc, biotite, and, locally, plagioclase, K-feldspar, muscovite, amphibole, stilpnomelane and ankerite. The overlying sediments are made up of banded iron formations and rare beds of siliciclastic rocks. Though the altered komatiites are pervasively silicified, SiO, contents do not exceed 58 wt.%, and their major and trace element geochemistry is similar to other komatiitic rocks of the Mendon Formation, particularly those of the M2v-member. Quartz veins and, less commonly, quartz-carbonate and quartz-carbonate-plagioclase veins are found throughout the core. Overall, composition and texture of the veins differ from primary and early diagenetic veins found in silicified komatiites elsewhere in the Barberton greenstone belt. In the BARB4 drill core, the veins are generally coarse-grained, and the immediate wall rocks are locally foliated along the vein margins. In addition, the δ18O values of vein quartz range from 14.1 to 15.3%o, significantly lower than the values typically found in veins on the modern seafloor that formed during low temperature hydrothermal seafloor alteration (∼22 to 32%o). Fluid inclusions in vein quartz are homogeneous two-phase (L+V) aqueous inclusions that occur in trans- and intragranular trails and clusters. Intragranular and isolated fluid inclusions have a similar homogenisation temperature (Th) of 130 to 200°C, with most data ranging between 145 and 175°C. Salinities cluster in three different groups of high (20 to 27wt.% NaCl equiv.), medium (10 to 15wt.% NaCl equiv.) and low salinity (0.3 to 1.5wt.% NaCl equiv.). The composition and microthermometric characteristics of the fluid inclusions analysed within the drill core show similarities to those found in quartz veins in silicified komatiites of the Mendon Formation, which are interpreted to have been entrapped during metamorphism. P-T calculations based on fluid inclusion microthermometry reveal conditions of 230 to 400 MPa and 250 to 400°C. Similar conditions of 240 to 270°C have been obtained using oxygen isotope thermometry, assuming a metamorphic fluid with a δ180 value of 6%o. Collectively, the δ18O values, together with the texture and composition of the veins, are interpreted to indicate a metamorphic origin of the veins. The presence of high salinity inclusions indicates the occurrence of a highly saline fluid that locally mixed with the dominant lower salinity fluids. The high salinity might have been derived from fluid circulation through evaporites. © 2016 December Geological Society of South Africa. Article 2016 English 10120750 10.2113/gssajg.119.4.639 South African Journal of Geology 119 Geological Society of South Africa 639 – 654 4 Barberton Greenstone Belt; banded iron formation; fluid inclusion; greenstone belt; komatiite; metamorphism; petrology; quartz vein; ultramafic rock https://www.scopus.com/inward/record.uri?eid=2-s2.0-85029700084&doi=10.2113%2fgssajg.119.4.639&partnerID=40&md5=1719e6002af7abf711c7995aff9cffc7 Cited by: 6 K. Farber A. Dziggel F.M. Meyer C. Harris article Sadori20161423 Lake Ohrid is located at the border between FYROM (Former Yugoslavian Republic of Macedonia) and Albania and formed during the latest phases of Alpine orogenesis. It is the deepest, the largest and the oldest tectonic lake in Europe. To better understand the paleoclimatic and paleoenvironmental evolution of Lake Ohrid, deep drilling was carried out in 2013 within the framework of the Scientific Collaboration on Past Speciation Conditions (SCOPSCO) project that was funded by the International Continental Scientific Drilling Program (ICDP). Preliminary results indicate that lacustrine sedimentation of Lake Ohrid started between 1.2 and 1.9 Ma ago. Here we present new pollen data (selected percentage and concentration taxa/groups) of the uppermost ∼ 200 m of the 569 m long DEEP core drilled in the depocentre of Lake Ohrid. The study is the fruit of a cooperative work carried out in several European palynological laboratories. The age model of this part of the core is based on 10 tephra layers and on tuning of biogeochemical proxy data to orbital parameters. According to the age model, the studied sequence covers the last ∼ 500 000 years at a millennial-scale resolution ( ∼ 1.6 ka) and records the major vegetation and climate changes that occurred during the last 12 (13 only pro parte) marine isotope stages (MIS). Our results indicate that there is a general good correspondence between forested/non-forested periods and glacial-interglacial cycles of the marine isotope stratigraphy. The record shows a progressive change from cooler and wetter to warmer and drier interglacial conditions. This shift in temperature and moisture availability is visible also in vegetation during glacial periods. The period corresponding to MIS11 (pollen assemblage zone OD-10, 428-368 ka BP) is dominated by montane trees such as conifers. Mesophilous elements such as deciduous and semi-deciduous oaks dominate forest periods of MIS5 (PASZ OD-3, 129-70 ka BP) and MIS1 (PASZ OD-1, 14 ka BP to present). Moreover, MIS7 (PASZ OD-6, 245-190 ka) shows a very high interglacial variability, with alternating expansions of montane and mesophilous arboreal taxa. Grasslands (open vegetation formations requiring relatively humid conditions) characterize the earlier glacial phases of MIS12 (PASZ OD-12, 488-459 ka), MIS10 (corresponding to the central part of PASZ OD-10, 428-366 ka) and MIS8 (PASZ OD-7, 288-245 ka). Steppes (open vegetation formations typical of dry environments) prevail during MIS6 (OD-5 and OD-4, 190-129 ka) and during MIS4-2 (PASZ OD-2, 70-14 ka). Our palynological results support the notion that Lake Ohrid has been a refugium area for both temperate and montane trees during glacials. Closer comparisons with other long southern European and Near Eastern pollen records will be achieved through ongoing high-resolution studies. © 2016 Author(s). Article 2016 English 17264170 10.5194/bg-13-1423-2016 Biogeosciences 13 Copernicus GmbH 1423 – 1437 Dipartimento di Biologia Ambientale, Università di Roma 'La Sapienza', Rome, Italy; Paleoenvironmental Dynamics Group, Institute of Earth Sciences, Heidelberg University, Heidelberg, Germany; Institute of Geography and Education, University of Cologne, Cologne, Germany; Dipartimento di Scienze della Terra, Università di Firenze, Florence, Italy; HNHP - Histoire Naturelle de l'Homme Préhistorique, UMR 7194 CNRS, Département de Préhistoire, Muséum National d'Histoire Naturelle, Institut de Paléontologie Humaine, Paris, France; Institute for Geology and Mineralogy, University of Cologne, Cologne, Germany; Faculty of Geology and Geoenvironment, National and Kapodistrian University of Athens, Athens, Greece; CNRS UMR 5554, Institut des Sciences de l'Evolution de Montpellier, Université de Montpellier, Montpellier, France; Dipartimento di Scienze della Vita, Laboratorio di Palinologia e Paleobotanica, Università di Modena e Reggio Emilia, Modena, Italy; Dipartimento di Scienze della Terra, University of Pisa, Pisa, Italy; Palaeoecology, Department of Physical Geography, Utrecht University, Utrecht, Netherlands 5 Albania; Lake Ohrid; Macedonia [Southern Europe]; Coniferophyta; Quercus; Alpine orogeny; biogeochemical cycle; biostratigraphy; climate variation; core analysis; deep drilling; interglacial; marine isotope stage; montane forest; paleobotany; paleoclimate; paleoenvironment; palynology; proxy climate record; refugium; tephra; vegetation dynamics https://www.scopus.com/inward/record.uri?eid=2-s2.0-84960332255&doi=10.5194%2fbg-13-1423-2016&partnerID=40&md5=863f1a44918d84c93d1c7d84c878415f Cited by: 116; All Open Access, Gold Open Access, Green Open Access Laura Sadori Andreas Koutsodendris Konstantinos Panagiotopoulos Alessia Masi Adele Bertini Nathalie Combourieu-Nebout Alexander Francke Katerina Kouli Sebastien Joannin Anna Maria Mercuri Odile Peyron Paola Torri Bernd Wagner Giovanni Zanchetta Gaia Sinopoli Timme H. Donders article Heise201611 In clinical trials investigating human health and in the analysis of microbial communities in cultures and natural environments, it is a substantial challenge to differentiate between living, potentially active communities and dead cells. The DNA-intercalating dye propidium monoazide (PMA) enables the selective masking of DNA from dead, membrane-compromised cells immediately before DNA extraction. In the present study, we evaluated for the first time a PMA treatment for methanogenic archaea in cultures and particle-rich environmental samples. Using microscopic analyses, we confirmed the applicability of the LIVE/DEAD® BacLight™ kit to methanogenic archaea and demonstrated the maintenance of intact cell membranes of methanogens in the presence of PMA. Although strain-specific differences in the efficiency of PMA treatment to methanogenic archaea were observed, we developed an optimal procedure using 130μM PMA and 5min of photo-activation with blue LED light. The results showed that the effectiveness of the PMA treatment strongly depends on the texture of the sediment/soil: silt and clay-rich sediments represent a challenge at all concentrations, whereas successful suppression of DNA from dead cells with compromised membranes was possible for low particle loads of sandy soil (total suspended solids (TSS)≤200mgmL-1). Conclusively, we present two strategies to overcome the problem of insufficient light activation of PMA caused by the turbidity effect (shielding) in particle-rich environmental samples by (i) dilution of the particle-rich sample and (ii) detachment of the cells and the free DNA from the sediment prior to a PMA treatment. Both strategies promise to be usable options for distinguishing living cells and free DNA in complex environmental samples. © 2015 Elsevier B.V. 2016 English 01677012 10.1016/j.mimet.2015.12.002 Journal of Microbiological Methods 121 Elsevier 11-23 GFZ German Research Centre for Geosciences, Helmholtz Centre Potsdam, Section Geomicrobiology, Telegrafenberg, Potsdam, 14473, Germany; Department of Environmental Microbiology, Technical University Berlin, Ernst-Reuter-Platz 1, Berlin, 10587, Germany DNA; dye; propidium monoazide; unclassified drug; azide; bacterial DNA; humic substance; intercalating agent; propidium iodide; propidium monoazide; soil, Article; bacterial strain; cell membrane; cell viability; clay rich sediment; controlled study; culture technique; denaturing gradient gel electrophoresis; diagnostic kit; environment; feasibility study; fluorescence; humic substance; led light; light; membrane permeability; methanogenic archaeon; microscopy; nonhuman; particle rich environmental sample; particle size; photoactivation; polymerase chain reaction; priority journal; quantitative analysis; sandy soil; sediment; silt sediment; soil texture; suspended particulate matter; turbidity; analogs and derivatives; analysis; chemistry; classification; drug effects; Euryarchaeota; fluorescence microscopy; genetics; humic substance; isolation and purification; microbial viability; microbiological examination; microbiology; procedures; soil, Azides; Bacteriological Techniques; DNA, Bacterial; Environmental Microbiology; Euryarchaeota; Humic Substances; Intercalating Agents; Microbial Viability; Microscopy, Fluorescence; Polymerase Chain Reaction; Propidium; Soil; Soil Microbiology https://www.scopus.com/inward/record.uri?eid=2-s2.0-84949685292&doi=10.1016%2fj.mimet.2015.12.002&partnerID=40&md5=cf17d2211c9c8dff6845599c6bf42b6c cited By 25 J. Heise M. Nega M. Alawi D. Wagner article Wilke2016118 Sedimentary sequences in ancient or long-lived lakes can reach several thousands of meters in thickness and often provide an unrivalled perspective of the lake's regional climatic, environmental, and biological history. Over the last few years, deep-drilling projects in ancient lakes became increasingly multi- and interdisciplinary, as, among others, seismological, sedimentological, biogeochemical, climatic, environmental, paleontological, and evolutionary information can be obtained from sediment cores. However, these multi- and interdisciplinary projects pose several challenges. The scientists involved typically approach problems from different scientific perspectives and backgrounds, and setting up the program requires clear communication and the alignment of interests. One of the most challenging tasks, besides the actual drilling operation, is to link diverse datasets with varying resolution, data quality, and age uncertainties to answer interdisciplinary questions synthetically and coherently. These problems are especially relevant when secondary data, i.e., datasets obtained independently of the drilling operation, are incorporated in analyses. Nonetheless, the inclusion of secondary information, such as isotopic data from fossils found in outcrops or genetic data from extant species, may help to achieve synthetic answers. Recent technological and methodological advances in paleolimnology are likely to increase the possibilities of integrating secondary information. Some of the new approaches have started to revolutionize scientific drilling in ancient lakes, but at the same time, they also add a new layer of complexity to the generation and analysis of sediment-core data. The enhanced opportunities presented by new scientific approaches to study the paleolimnological history of these lakes, therefore, come at the expense of higher logistic, communication, and analytical efforts. Here we review types of data that can be obtained in ancient lake drilling projects and the analytical approaches that can be applied to empirically and statistically link diverse datasets to create an integrative perspective on geological and biological data. In doing so, we highlight strengths and potential weaknesses of new methods and analyses, and provide recommendations for future interdisciplinary deep-drilling projects. © 2016 Elsevier B.V. Review 2016 English 09218181 10.1016/j.gloplacha.2016.05.005 Global and Planetary Change 143 Elsevier B.V. 118 – 151 Biology; Geology; Paleolimnology; Analytical approach; Ancient lakes; Deep drilling; Evolutionary biology; Evolutionary information; Interdisciplinary project; Methodology; Sedimentary sequence; biological survey; core analysis; data quality; deep drilling; evolutionary biology; fossil record; geological theory; integrated approach; lacustrine environment; outcrop; paleolimnology; technological change; Lakes https://www.scopus.com/inward/record.uri?eid=2-s2.0-84975523752&doi=10.1016%2fj.gloplacha.2016.05.005&partnerID=40&md5=65b5fcf6cccc099d292cd51ee6749ff8 Cited by: 29; All Open Access, Bronze Open Access, Green Open Access Thomas Wilke Bernd Wagner Bert Van Bocxlaer Christian Albrecht Daniel Ariztegui Diana Delicado Alexander Francke Mathias Harzhauser Torsten Hauffe Jens Holtvoeth Janna Just Melanie J. Leng Zlatko Levkov Kirsty Penkman Laura Sadori Alister Skinner Björn Stelbrink Hendrik Vogel Frank Wesselingh Thomas Wonik article Vuillemin20162475 Article 2016 10.5194/bg-13-2475-2016 Biogeosciences 13 2475 – 2492 8 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84966425171&doi=10.5194%2fbg-13-2475-2016&partnerID=40&md5=1eb33421f3b5f2b79cacce210875a06b Cited by: 19; All Open Access, Gold Open Access, Green Open Access Aurèle Vuillemin Daniel Ariztegui Peter R. Leavitt Lynda Bunting Flavio Anselmetti Hugo Corbella Pierre Francus Andreas Lücke Nora I. Maidana Christian Ohlendorf Frank Schäbitz Stefan Wastegård Bernd Zolitschka article 2016 10.7605/gdlxb.2016.05.065 Journal of Palaeogeography 18 857-864 5 Y. Cha X. Wu D. Yu article Wilke2016118 Sedimentary sequences in ancient or long-lived lakes can reach several thousands of meters in thickness and often provide an unrivalled perspective of the lake's regional climatic, environmental, and biological history. Over the last few years, deep-drilling projects in ancient lakes became increasingly multi- and interdisciplinary, as, among others, seismological, sedimentological, biogeochemical, climatic, environmental, paleontological, and evolutionary information can be obtained from sediment cores. However, these multi- and interdisciplinary projects pose several challenges. The scientists involved typically approach problems from different scientific perspectives and backgrounds, and setting up the program requires clear communication and the alignment of interests. One of the most challenging tasks, besides the actual drilling operation, is to link diverse datasets with varying resolution, data quality, and age uncertainties to answer interdisciplinary questions synthetically and coherently. These problems are especially relevant when secondary data, i.e., datasets obtained independently of the drilling operation, are incorporated in analyses. Nonetheless, the inclusion of secondary information, such as isotopic data from fossils found in outcrops or genetic data from extant species, may help to achieve synthetic answers. Recent technological and methodological advances in paleolimnology are likely to increase the possibilities of integrating secondary information. Some of the new approaches have started to revolutionize scientific drilling in ancient lakes, but at the same time, they also add a new layer of complexity to the generation and analysis of sediment-core data. The enhanced opportunities presented by new scientific approaches to study the paleolimnological history of these lakes, therefore, come at the expense of higher logistic, communication, and analytical efforts. Here we review types of data that can be obtained in ancient lake drilling projects and the analytical approaches that can be applied to empirically and statistically link diverse datasets to create an integrative perspective on geological and biological data. In doing so, we highlight strengths and potential weaknesses of new methods and analyses, and provide recommendations for future interdisciplinary deep-drilling projects. © 2016 Elsevier B.V. Review 2016 English 09218181 10.1016/j.gloplacha.2016.05.005 Global and Planetary Change 143 Elsevier B.V. 118 – 151 Biology; Geology; Paleolimnology; Analytical approach; Ancient lakes; Deep drilling; Evolutionary biology; Evolutionary information; Interdisciplinary project; Methodology; Sedimentary sequence; biological survey; core analysis; data quality; deep drilling; evolutionary biology; fossil record; geological theory; integrated approach; lacustrine environment; outcrop; paleolimnology; technological change; Lakes https://www.scopus.com/inward/record.uri?eid=2-s2.0-84975523752&doi=10.1016%2fj.gloplacha.2016.05.005&partnerID=40&md5=65b5fcf6cccc099d292cd51ee6749ff8 Cited by: 30; All Open Access, Bronze Open Access, Green Open Access Thomas Wilke Bernd Wagner Bert Van Bocxlaer Christian Albrecht Daniel Ariztegui Diana Delicado Alexander Francke Mathias Harzhauser Torsten Hauffe Jens Holtvoeth Janna Just Melanie J. Leng Zlatko Levkov Kirsty Penkman Laura Sadori Alister Skinner Björn Stelbrink Hendrik Vogel Frank Wesselingh Thomas Wonik article Wilke2016118 Sedimentary sequences in ancient or long-lived lakes can reach several thousands of meters in thickness and often provide an unrivalled perspective of the lake's regional climatic, environmental, and biological history. Over the last few years, deep-drilling projects in ancient lakes became increasingly multi- and interdisciplinary, as, among others, seismological, sedimentological, biogeochemical, climatic, environmental, paleontological, and evolutionary information can be obtained from sediment cores. However, these multi- and interdisciplinary projects pose several challenges. The scientists involved typically approach problems from different scientific perspectives and backgrounds, and setting up the program requires clear communication and the alignment of interests. One of the most challenging tasks, besides the actual drilling operation, is to link diverse datasets with varying resolution, data quality, and age uncertainties to answer interdisciplinary questions synthetically and coherently. These problems are especially relevant when secondary data, i.e., datasets obtained independently of the drilling operation, are incorporated in analyses. Nonetheless, the inclusion of secondary information, such as isotopic data from fossils found in outcrops or genetic data from extant species, may help to achieve synthetic answers. Recent technological and methodological advances in paleolimnology are likely to increase the possibilities of integrating secondary information. Some of the new approaches have started to revolutionize scientific drilling in ancient lakes, but at the same time, they also add a new layer of complexity to the generation and analysis of sediment-core data. The enhanced opportunities presented by new scientific approaches to study the paleolimnological history of these lakes, therefore, come at the expense of higher logistic, communication, and analytical efforts. Here we review types of data that can be obtained in ancient lake drilling projects and the analytical approaches that can be applied to empirically and statistically link diverse datasets to create an integrative perspective on geological and biological data. In doing so, we highlight strengths and potential weaknesses of new methods and analyses, and provide recommendations for future interdisciplinary deep-drilling projects. © 2016 Elsevier B.V. 2016 English 09218181 10.1016/j.gloplacha.2016.05.005 Global and Planetary Change 143 Elsevier B.V. 118-151 Department of Animal Ecology and Systematics, Justus Liebig University Giessen, Giessen, Germany; Institute of Geology and Mineralogy, University of Cologne, Cologne, Germany; Collaborative Research Center 806 - Our Way to Europe, University of Cologne, Cologne, Germany; Limnology Research Unit, Ghent University, Ghent, Belgium; Museum für Naturkunde - Leibniz Institute for Evolution and Biodiversity Science, Berlin, Germany; Department of Earth Sciences, University of Geneva, Geneva, Switzerland; Geological-Paleontological Department, Natural History Museum Vienna, Vienna, Austria; School of Chemistry, University of Bristol, Bristol, United Kingdom; Centre for Environmental Geochemistry, School of Geography, University of Nottingham, Nottingham, United Kingdom; NERC Isotope Geosciences Facilities, British Geological Survey, Keyworth, Nottingham, United Kingdom; Institute of Biology, University Ss Cyril and Methodius, Skopje, North Macedonia; Department of Chemistry, University of York, York, United Kingdom; Dipartimento di Biologia Ambientale, Università di Roma La Sapienza, Rome, Italy; ACS Core Services, Edinburgh, United Kingdom; Institute of Geological Sciences and Oeschger Centre for Climate Change Research, University of Bern, Bern, Switzerland; Naturalis Biodiversity Center, Leiden, Netherlands; Leibniz Institute for Applied Geophysics, Hannover, Germany Biology; Geology; Paleolimnology, Analytical approach; Ancient lakes; Deep drilling; Evolutionary biology; Evolutionary information; Interdisciplinary project; Methodology; Sedimentary sequence, Lakes, biological survey; core analysis; data quality; deep drilling; evolutionary biology; fossil record; geological theory; integrated approach; lacustrine environment; outcrop; paleolimnology; technological change https://www.scopus.com/inward/record.uri?eid=2-s2.0-84975523752&doi=10.1016%2fj.gloplacha.2016.05.005&partnerID=40&md5=65b5fcf6cccc099d292cd51ee6749ff8 cited By 29 T. Wilke B. Wagner B. Van Bocxlaer C. Albrecht D. Ariztegui D. Delicado A. Francke M. Harzhauser T. Hauffe J. Holtvoeth J. Just M.J. Leng Z. Levkov K. Penkman L. Sadori A. Skinner B. Stelbrink H. Vogel F. Wesselingh T. Wonik article Wilke2016118 Sedimentary sequences in ancient or long-lived lakes can reach several thousands of meters in thickness and often provide an unrivalled perspective of the lake's regional climatic, environmental, and biological history. Over the last few years, deep-drilling projects in ancient lakes became increasingly multi- and interdisciplinary, as, among others, seismological, sedimentological, biogeochemical, climatic, environmental, paleontological, and evolutionary information can be obtained from sediment cores. However, these multi- and interdisciplinary projects pose several challenges. The scientists involved typically approach problems from different scientific perspectives and backgrounds, and setting up the program requires clear communication and the alignment of interests. One of the most challenging tasks, besides the actual drilling operation, is to link diverse datasets with varying resolution, data quality, and age uncertainties to answer interdisciplinary questions synthetically and coherently. These problems are especially relevant when secondary data, i.e., datasets obtained independently of the drilling operation, are incorporated in analyses. Nonetheless, the inclusion of secondary information, such as isotopic data from fossils found in outcrops or genetic data from extant species, may help to achieve synthetic answers. Recent technological and methodological advances in paleolimnology are likely to increase the possibilities of integrating secondary information. Some of the new approaches have started to revolutionize scientific drilling in ancient lakes, but at the same time, they also add a new layer of complexity to the generation and analysis of sediment-core data. The enhanced opportunities presented by new scientific approaches to study the paleolimnological history of these lakes, therefore, come at the expense of higher logistic, communication, and analytical efforts. Here we review types of data that can be obtained in ancient lake drilling projects and the analytical approaches that can be applied to empirically and statistically link diverse datasets to create an integrative perspective on geological and biological data. In doing so, we highlight strengths and potential weaknesses of new methods and analyses, and provide recommendations for future interdisciplinary deep-drilling projects. © 2016 Elsevier B.V. 2016 English 09218181 10.1016/j.gloplacha.2016.05.005 Global and Planetary Change 143 Elsevier B.V. 118-151 Department of Animal Ecology and Systematics, Justus Liebig University Giessen, Giessen, Germany; Institute of Geology and Mineralogy, University of Cologne, Cologne, Germany; Collaborative Research Center 806 - Our Way to Europe, University of Cologne, Cologne, Germany; Limnology Research Unit, Ghent University, Ghent, Belgium; Museum für Naturkunde - Leibniz Institute for Evolution and Biodiversity Science, Berlin, Germany; Department of Earth Sciences, University of Geneva, Geneva, Switzerland; Geological-Paleontological Department, Natural History Museum Vienna, Vienna, Austria; School of Chemistry, University of Bristol, Bristol, United Kingdom; Centre for Environmental Geochemistry, School of Geography, University of Nottingham, Nottingham, United Kingdom; NERC Isotope Geosciences Facilities, British Geological Survey, Keyworth, Nottingham, United Kingdom; Institute of Biology, University Ss Cyril and Methodius, Skopje, North Macedonia; Department of Chemistry, University of York, York, United Kingdom; Dipartimento di Biologia Ambientale, Università di Roma La Sapienza, Rome, Italy; ACS Core Services, Edinburgh, United Kingdom; Institute of Geological Sciences and Oeschger Centre for Climate Change Research, University of Bern, Bern, Switzerland; Naturalis Biodiversity Center, Leiden, Netherlands; Leibniz Institute for Applied Geophysics, Hannover, Germany Biology; Geology; Paleolimnology, Analytical approach; Ancient lakes; Deep drilling; Evolutionary biology; Evolutionary information; Interdisciplinary project; Methodology; Sedimentary sequence, Lakes, biological survey; core analysis; data quality; deep drilling; evolutionary biology; fossil record; geological theory; integrated approach; lacustrine environment; outcrop; paleolimnology; technological change https://www.scopus.com/inward/record.uri?eid=2-s2.0-84975523752&doi=10.1016%2fj.gloplacha.2016.05.005&partnerID=40&md5=65b5fcf6cccc099d292cd51ee6749ff8 cited By 24 T. Wilke B. Wagner B. Van Bocxlaer C. Albrecht D. Ariztegui D. Delicado A. Francke M. Harzhauser T. Hauffe J. Holtvoeth J. Just M.J. Leng Z. Levkov K. Penkman L. Sadori A. Skinner B. Stelbrink H. Vogel F. Wesselingh T. Wonik article WILKE2016118 Sedimentary sequences in ancient or long-lived lakes can reach several thousands of meters in thickness and often provide an unrivalled perspective of the lake's regional climatic, environmental, and biological history. Over the last few years, deep-drilling projects in ancient lakes became increasingly multi- and interdisciplinary, as, among others, seismological, sedimentological, biogeochemical, climatic, environmental, paleontological, and evolutionary information can be obtained from sediment cores. However, these multi- and interdisciplinary projects pose several challenges. The scientists involved typically approach problems from different scientific perspectives and backgrounds, and setting up the program requires clear communication and the alignment of interests. One of the most challenging tasks, besides the actual drilling operation, is to link diverse datasets with varying resolution, data quality, and age uncertainties to answer interdisciplinary questions synthetically and coherently. These problems are especially relevant when secondary data, i.e., datasets obtained independently of the drilling operation, are incorporated in analyses. Nonetheless, the inclusion of secondary information, such as isotopic data from fossils found in outcrops or genetic data from extant species, may help to achieve synthetic answers. Recent technological and methodological advances in paleolimnology are likely to increase the possibilities of integrating secondary information. Some of the new approaches have started to revolutionize scientific drilling in ancient lakes, but at the same time, they also add a new layer of complexity to the generation and analysis of sediment-core data. The enhanced opportunities presented by new scientific approaches to study the paleolimnological history of these lakes, therefore, come at the expense of higher logistic, communication, and analytical efforts. Here we review types of data that can be obtained in ancient lake drilling projects and the analytical approaches that can be applied to empirically and statistically link diverse datasets to create an integrative perspective on geological and biological data. In doing so, we highlight strengths and potential weaknesses of new methods and analyses, and provide recommendations for future interdisciplinary deep-drilling projects. 2016 0921-8181 https://doi.org/10.1016/j.gloplacha.2016.05.005 Global and Planetary Change 143 118-151 Ancient lake, Long-lived lake, Deep drilling, Evolutionary biology, Methodology, Paleolimnology https://www.sciencedirect.com/science/article/pii/S0921818115300746 Thomas Wilke Bert {Van Bocxlaer} Christian Albrecht Daniel Ariztegui Diana Delicado Alexander Francke Mathias Harzhauser Torsten Hauffe Jens Holtvoeth Janna Just Zlatko Levkov Kirsty Penkman Laura Sadori Alister Skinner Björn Stelbrink Hendrik Vogel Frank Wesselingh Thomas Wonik article Wilke2016118 Sedimentary sequences in ancient or long-lived lakes can reach several thousands of meters in thickness and often provide an unrivalled perspective of the lake's regional climatic, environmental, and biological history. Over the last few years, deep-drilling projects in ancient lakes became increasingly multi- and interdisciplinary, as, among others, seismological, sedimentological, biogeochemical, climatic, environmental, paleontological, and evolutionary information can be obtained from sediment cores. However, these multi- and interdisciplinary projects pose several challenges. The scientists involved typically approach problems from different scientific perspectives and backgrounds, and setting up the program requires clear communication and the alignment of interests. One of the most challenging tasks, besides the actual drilling operation, is to link diverse datasets with varying resolution, data quality, and age uncertainties to answer interdisciplinary questions synthetically and coherently. These problems are especially relevant when secondary data, i.e., datasets obtained independently of the drilling operation, are incorporated in analyses. Nonetheless, the inclusion of secondary information, such as isotopic data from fossils found in outcrops or genetic data from extant species, may help to achieve synthetic answers. Recent technological and methodological advances in paleolimnology are likely to increase the possibilities of integrating secondary information. Some of the new approaches have started to revolutionize scientific drilling in ancient lakes, but at the same time, they also add a new layer of complexity to the generation and analysis of sediment-core data. The enhanced opportunities presented by new scientific approaches to study the paleolimnological history of these lakes, therefore, come at the expense of higher logistic, communication, and analytical efforts. Here we review types of data that can be obtained in ancient lake drilling projects and the analytical approaches that can be applied to empirically and statistically link diverse datasets to create an integrative perspective on geological and biological data. In doing so, we highlight strengths and potential weaknesses of new methods and analyses, and provide recommendations for future interdisciplinary deep-drilling projects. © 2016 Elsevier B.V. 2016 English 09218181 10.1016/j.gloplacha.2016.05.005 Global and Planetary Change 143 Elsevier B.V. 118-151 Department of Animal Ecology and Systematics, Justus Liebig University Giessen, Giessen, Germany; Institute of Geology and Mineralogy, University of Cologne, Cologne, Germany; Collaborative Research Center 806 - Our Way to Europe, University of Cologne, Cologne, Germany; Limnology Research Unit, Ghent University, Ghent, Belgium; Museum für Naturkunde - Leibniz Institute for Evolution and Biodiversity Science, Berlin, Germany; Department of Earth Sciences, University of Geneva, Geneva, Switzerland; Geological-Paleontological Department, Natural History Museum Vienna, Vienna, Austria; School of Chemistry, University of Bristol, Bristol, United Kingdom; Centre for Environmental Geochemistry, School of Geography, University of Nottingham, Nottingham, United Kingdom; NERC Isotope Geosciences Facilities, British Geological Survey, Keyworth, Nottingham, United Kingdom; Institute of Biology, University Ss Cyril and Methodius, Skopje, North Macedonia; Department of Chemistry, University of York, York, United Kingdom; Dipartimento di Biologia Ambientale, Università di Roma La Sapienza, Rome, Italy; ACS Core Services, Edinburgh, United Kingdom; Institute of Geological Sciences and Oeschger Centre for Climate Change Research, University of Bern, Bern, Switzerland; Naturalis Biodiversity Center, Leiden, Netherlands; Leibniz Institute for Applied Geophysics, Hannover, Germany Biology; Geology; Paleolimnology, Analytical approach; Ancient lakes; Deep drilling; Evolutionary biology; Evolutionary information; Interdisciplinary project; Methodology; Sedimentary sequence, Lakes, biological survey; core analysis; data quality; deep drilling; evolutionary biology; fossil record; geological theory; integrated approach; lacustrine environment; outcrop; paleolimnology; technological change https://www.scopus.com/inward/record.uri?eid=2-s2.0-84975523752&doi=10.1016%2fj.gloplacha.2016.05.005&partnerID=40&md5=65b5fcf6cccc099d292cd51ee6749ff8 cited By 26 T. Wilke B. Wagner B. Van Bocxlaer C. Albrecht D. Ariztegui D. Delicado A. Francke M. Harzhauser T. Hauffe J. Holtvoeth J. Just M.J. Leng Z. Levkov K. Penkman L. Sadori A. Skinner B. Stelbrink H. Vogel F. Wesselingh T. Wonik conference Buness2016 Overdeepened valleys and basin can be found in glaciated regions worldwide. Due to their geological, ecological, and societal relevance they constitute a relevant geoscientific target. In preparation for an ICDP project (Drilling Overdeepened Alpine Valleys, DOVE), we carried out several reflection seismic surveys using high-resolution P-wave, horizontally pola¬ri¬zed SH-wave, and multi-component (SV-And SH-wave sources, 3-component re¬ceiver) techniques at a test site in the Tannwald basin north of Lake Constance. The first results of the P-And SH-wave reflection profiles are presented here. The seismic sections image well the internal valley structure of the Tannwald Basin; different facies are also distinguishable in the glacial sediments. The combined inter¬pretation of P-wave and SH-wave reflection seismics reveal more details than just one technique on its own by providing complementary information. P-wave seismics show a more coherent image with a higher penetration depth, while SHwave seismics partly resolve more details due to their higher resolution. The combination promises to be an enhanced tool to investigate sedimentary successions in advance of scientific drilling. 2016 English 22nd European Meeting of Environmental and Engineering Geophysics, Near Surface Geoscience 2016 European Association of Geoscientists and Engineers, EAGE Leibniz Institute for Applied Geophysics (LIAG), Germany Geology; Geophysics; Landforms; Seismic waves; Seismology, Coherent images; Glacial sediments; High resolution; Higher resolution; Multicomponents; Reflection seismic; Scientific drilling; Seismic sections, Shear waves https://www.scopus.com/inward/record.uri?eid=2-s2.0-85007363519&partnerID=40&md5=e314ca6b510deb4b69c0bd8b9d885383 cited By 0 H. Buness T. Burschil G. Gabriel article Andreev2016245 The sediment record of Lake El'gygytgyn (67°30′N, 172°05′E) spans the past 3.6 Ma and provides unique opportunities for qualitative and quantitative reconstructions of the regional paleoenvironmental history of the terrestrial Arctic. Millennial-scale pollen studies of the sediments that accumulated during the Late Pliocene and Early Pleistocene (ca. 2.7 to 2.5 Ma) demonstrate orbitally-driven vegetation and climate changes during this transitional interval. Pollen spectra show a significant vegetation shift at the Pliocene/Pleistocene boundary that is, however, delayed by a few thousand years compared to lacustrine response. About 2.70–2.68 Ma the vegetation at Lake El'gygytgyn, currently a tundra area was mostly dominated by larch forests with some shrub pine, shrub alder and dwarf birch in understory. During the marine isotope stages G3 and G1, ca. 2.665–2.647 and 2.625–2.617 Ma, some spruce trees grew in the local larch-pine forests, pointing to relatively warm climate conditions. At the beginning of the Pleistocene, around 2.588 Ma, a prominent climatic deterioration led to a change from larch-dominated forests to predominantly treeless steppe- and tundra-like habitats. Between ca. 2.56–2.53 Ma some climate amelioration is reflected by the higher presence of coniferous taxa (mostly pine and larch, but probably also spruce) in the area. After 2.53 Ma a relatively cold and dry climate became dominant again, leading to open steppe-like and shrubby environments followed by climate amelioration between ca. 2.510 and 2.495 Ma, when pollen assemblages show that larch forests with dwarf birch and shrub alder still grew in the lake's vicinity. Increased contents of green algae colonies (Botryococcus) remains and Zygnema cysts around 2.691–2.689, 2.679–2.677, 2.601–2.594, 2.564–2.545, and 2.532–2.510 Ma suggest a spread of shallow-water environments most likely due to a lake-level lowering. These events occurred simultaneously with dry climate conditions inferred from broad distribution of steppe habitats with Artemisia and other herbs. © 2016 Elsevier Ltd 2016 English 02773791 10.1016/j.quascirev.2016.03.030 Quaternary Science Reviews 147 Elsevier Ltd 245-258 Institute of Geology and Mineralogy, University of Cologne, Zülpicher Str. 49a, Cologne, 50674, Germany; Institute of Geology and Petroleum Technologies, Kazan Federal University, Kremlyovskaya Str. 18, Kazan, 420008, Russian Federation; Free University Berlin, Institute of Geological Sciences, Palaeontology, Malteserstr. 74-100, Building D, Berlin, 12249, Germany Algae; Climate change; Ecosystems; Forestry; Vegetation, Early pleistocene; Marine isotope stages; North-easter Russian Arctic; Pliocene; Pollen assemblage; Pollen record; Shallow water environment; Vegetation change, Lakes, climate variation; coniferous tree; fossil record; herb; lacustrine deposit; lake level; marine isotope stage; paleobotany; paleoenvironment; palynology; Pliocene-Pleistocene boundary; shrub; vegetation dynamics, Arctic; Russian Federation, Alnus; Artemisia; Betula nana; Botryococcus; Chlorophyta; Larix; Picea; Zygnema https://www.scopus.com/inward/record.uri?eid=2-s2.0-84970016781&doi=10.1016%2fj.quascirev.2016.03.030&partnerID=40&md5=63865b8829853a165c872bd5ce58dcf0 cited By 19 A.A. Andreev P.E. Tarasov V. Wennrich M. Melles article Liu201613007 In the context of well drilling and during the process of drilling down and tripping out of drill string, it is the inevitable contact and friction between drill pipe and casing that causes the wear of the drill pipe and casing tube, especially in the case of drilling deep, ultra-deep, and horizontal wells. Compared with steel drill pipe, the wear of aluminum alloy drill pipe appears to be more serious. Nanoparticles as additives in drilling fluids could potentially reduce mechanical friction, greatly enhancing the lubricating properties of drilling fluids and subsequently reducing the drill pipe and casing materials surface losses. Within this study an attempt has been made to improve the lubricating properties of drilling fluid with regard to deep, complicated drilling conditions by adding oxide nanoparticles to the fluid. Spherical alumina (Al2O3), titania (TiO2), silica (SiO8) and diamond nanoparticles were selected as drilling fluid additives. Effects of different types and concentrations of oxide nanoparticle additives on lubricating properties and friction reduction of drilling fluid have been studied by using an extreme pressure lubrication device and a pin-on-disk tester. In pin-on-disk tests, the pin material was AISI316 steel (casing material) and the disk material was 7075 aluminum alloy (drill pipe material). The pin-on-disk friction and wear tests were carried out under the condition that the pin and disk were immerged in drilling fluid. Results indicated that the lubricating properties of waterbased drilling fluid significantly improved upon adding an appropriate amount of SiO2 nanoparticles, meanwhile TiO2, Al2O3 and diamond nanoparticles had limited effects on the lubricating properties of drilling fluid. The LR (lubricating factor reduce rate) of drilling fluid increased to the maximum value of 16.6% at 0.5 wt% SiO2 nanoparticles addition. The WV (wear volume) of aluminum alloy disc decreased to the minimum value of 0.31 mm3 at 0.4 wt% SiO2 nanoparticles addition. On the basis of the above experimental results, 0.4 wt% SiO2 nanoparticles were added to the oil based drilling fluids used in SK-II well drilling, which is a scientific continental drilling project in the Cretaceous Songliao Basin of northeast China. Results showed that the lubricating coefficient of the drilling fluid was reduced by 20.3%, the friction factor reduction rate was increased by 29.7%, and the aluminum disc wear volume decreased by 26.3%. Copyright © 2016 American Scientific Publishers All rights reserved. 2016 English 15334880 10.1166/jnn.2016.13849 Journal of Nanoscience and Nanotechnology 16 American Scientific Publishers 13007-13013 College of Construction Engineering, Jilin University, Changchun, 130061, China; Key Lab. of Drilling and Exploitation Technology in Complex Conditions, Ministry of Land and Resources, Changchun, 130061, China; State Key Laboratory of Superhard Materials, Jilin University, Changchun, 130021, China 12 Alumina; Aluminum alloys; Aluminum oxide; Diamond drilling; Diamonds; Drill pipe; Drill strings; Drilling fluids; Drills; Friction; Horizontal drilling; Horizontal wells; Silica nanoparticles; Titanium dioxide; Tribology; Wear resistance, Diamond nano-particles; Drilling fluid additives; Lubricating properties; Lubrication devices; Oil-based drilling fluid; Pin on disk; Pin on disk friction; Water-based drilling fluid, Oil well drilling https://www.scopus.com/inward/record.uri?eid=2-s2.0-84994667718&doi=10.1166%2fjnn.2016.13849&partnerID=40&md5=70a42db1827c03863633c644a37e9f59 cited By 7 B.C. Liu S.Q. Liu Z.R. Chen Q.N. Meng C. Li article Stelbrink20161 Background: Ancient Lake Ohrid, located on the Albania-Macedonia border, is the most biodiverse freshwater lake in Europe. However, the processes that gave rise to its extraordinary endemic biodiversity, particularly in the species-rich gastropods, are still poorly understood. A suitable model taxon to study speciation processes in Lake Ohrid is the pulmonate snail genus Acroloxus, which comprises two morphologically distinct and ecologically (vertically) separated endemic species. Using a multilocus phylogenetic framework of Acroloxus limpets from the Euro-Mediterranean subregion, together with molecular-clock and phylogeographic analyses of Ohrid taxa, we aimed to infer their geographic origin and the timing of colonization as well as the role of geography and ecology in intra-lacustrine diversification. Results: In contrast to most other endemic invertebrate groups in Lake Ohrid, the phylogenetic relationships of the endemic Ohrid Acroloxus species indicate that the Balkan region probably did not serve as their ancestral area. The inferred monophyly and estimated divergence times further suggest that these freshwater limpets colonized the lake only once and that the onset of intra-lacustrine diversification coincides with the time when the lake reached deep-water conditions ca 1.3 Mya. However, the difference in vertical distribution of these two ecologically distinct species is not reflected in the phylogeographic pattern observed. Instead, western and eastern populations are genetically more distinct, suggesting a horizontal structure. Conclusions: We conclude that both geography and ecology have played a role in the intra-lacustrine speciation process. Given the distinct morphology (sculptured vs. smooth shell) and ecology (littoral vs. sublittoral), and the timing of intra-lacustrine diversification inferred, we propose that the onset of deep-water conditions initially triggered ecological speciation. Subsequent geographic processes then gave rise to the phylogeographic patterns observed today. However, the generally weak genetic differentiation observed suggests incipient speciation, which might be explained by the comparatively young age of the lake system and thus the relatively recent onset of intra-lacustrine diversification. © 2016 The Author(s). Article 2016 English 14712148 10.1186/s12862-016-0826-6 BMC Evolutionary Biology 16 BioMed Central 1 – 13 1 Animals; Biodiversity; DNA, Mitochondrial; Ecosystem; Europe; Genetic Speciation; Lakes; Models, Biological; Phylogeny; Phylogeography; Sequence Analysis, DNA; Snails; Albania; Balkan; Lake Ohrid; Macedonia [Southern Europe]; Turkmenistan; Acroloxidae; Acroloxus; Gastropoda; Invertebrata; Mya; Patellidae; mitochondrial DNA; biodiversity; divergence; endemic species; genetic differentiation; lacustrine environment; molecular ecology; morphology; origin of life; phylogenetics; phylogeny; phylogeography; snail; speciation (biology); vertical distribution; animal; biodiversity; biological model; DNA sequence; ecosystem; Europe; genetics; lake; phylogeny; phylogeography; snail; species differentiation https://www.scopus.com/inward/record.uri?eid=2-s2.0-85005939711&doi=10.1186%2fs12862-016-0826-6&partnerID=40&md5=71379cbf05f48ce403cf11524453ea2c Cited by: 17; All Open Access, Gold Open Access, Green Open Access Björn Stelbrink Alena A. Shirokaya Kirstin Föller Thomas Wilke Christian Albrecht article Lacey20161801 Lake Ohrid (Macedonia/Albania) is an ancient lake with unique biodiversity and a site of global significance for investigating the influence of climate, geological, and tectonic events on the generation of endemic populations. Here, we present oxygen (δ18O) and carbon (δ13C) isotope data from carbonate over the upper 243 m of a composite core profile recovered as part of the Scientific Collaboration on Past Speciation Conditions in Lake Ohrid (SCOPSCO) project. The investigated sediment succession covers the past ca. 637 ka. Previous studies on short cores from the lake (up to 15 m, &lt; 140 ka) have indicated the total inorganic carbon (TIC) content of sediments to be highly sensitive to climate change over the last glacial-interglacial cycle. Sediments corresponding to warmer periods contain abundant endogenic calcite; however, an overall low TIC content in glacial sediments is punctuated by discrete bands of early diagenetic authigenic siderite. Isotope measurements on endogenic calcite (δ18Oc and δ13Cc) reveal variations both between and within interglacials that suggest the lake has been subject to palaeoenvironmental change on orbital and millennial timescales. We also measured isotope ratios from authigenic siderite (δ18Os and δ13Cs) and, with the oxygen isotope composition of calcite and siderite, reconstruct δ18O of lake water (δ18Olw) over the last 637 ka. Interglacials have higher δ18Olw values when compared to glacial periods most likely due to changes in evaporation, summer temperature, the proportion of winter precipitation (snowfall), and inflow from adjacent Lake Prespa. The isotope stratigraphy suggests Lake Ohrid experienced a period of general stability from marine isotope stage (MIS) 15 to MIS 13, highlighting MIS 14 as a particularly warm glacial. Climate conditions became progressively wetter during MIS 11 and MIS 9. Interglacial periods after MIS 9 are characterised by increasingly evaporated and drier conditions through MIS 7, MIS 5, and the Holocene. Our results provide new evidence for long-term climate change in the northern Mediterranean region, which will form the basis to better understand the influence of major environmental events on biological evolution within Lake Ohrid. © Author(s) 2016. 2016 English 17264170 10.5194/bg-13-1801-2016 Biogeosciences 13 Copernicus GmbH 1801-1820 Centre for Environmental Geochemistry, School of Geography, University of Nottingham, Nottingham, NG7 2RD, United Kingdom; NERC Isotope Geosciences Facilities, British Geological Survey, Keyworth, Nottingham, NG12 5GG, United Kingdom; Institute of Geology and Mineralogy, University of Cologne, Cologne, 50674, Germany; British Geological Survey, Keyworth, Nottingham, NG12 5GG, United Kingdom; Institute of Geological Sciences, Oeschger Centre for Climate Change Research, University of Bern, Bern, 3012, Switzerland; Leibniz Institute for Applied Geophysics, Hannover, 30655, Germany; Dipartimento di Scienze della Terra, University of Pisa, Pisa, Italy 6 calcite; carbon isotope; climate variation; core analysis; glacial-interglacial cycle; long-term change; marine isotope stage; Mediterranean environment; oxygen isotope; paleoenvironment; reconstruction; siderite; stable isotope, Lake Mikri Prespa; Lake Ohrid https://www.scopus.com/inward/record.uri?eid=2-s2.0-84963995224&doi=10.5194%2fbg-13-1801-2016&partnerID=40&md5=3d455c62e05f8a34b29243460371def6 cited By 31 J.H. Lacey M.J. Leng A. Francke J.H. Sloane A. Milodowski H. Vogel H. Baumgarten G. Zanchetta B. Wagner article Fritz20162441 A Paleoarchean impact spherule-bearing interval of the 763 m long International Continental Scientific Drilling Program (ICDP) drill core BARB5 from the lower Mapepe Formation of the Fig Tree Group, Barberton Mountain Land (South Africa) was investigated using nondestructive analytical techniques. The results of visual observation, infrared (IR) spectroscopic imaging, and micro-X-ray fluorescence (μXRF) of drill cores are presented. Petrographic and sedimentary features, as well as major and trace element compositions of lithologies from the micrometer to kilometer-scale, assisted in the localization and characterization of eight spherule-bearing intervals between 512.6 and 510.5 m depth. The spherule layers occur in a strongly deformed section between 517 and 503 m, and the rocks in the core above and below are clearly less disturbed. The μXRF element maps show that spherule layers have similar petrographic and geochemical characteristics but differences in (1) sorting of two types of spherules and (2) occurrence of primary minerals (Ni-Cr spinel and zircon). We favor a single impact scenario followed by postimpact reworking, and subsequent alteration. The spherule layers are Al2O3-rich and can be distinguished from the Al2O3-poor marine sediments by distinct Al-OH absorption features in the short wave infrared (SWIR) region of the electromagnetic spectrum. Infrared images can cover tens to hundreds of square meters of lithologies and, thus, may be used to search for Al-OH-rich spherule layers in Al2O3-poor sediments, such as Eoarchean metasediments, where the textural characteristics of the spherule layers are obscured by metamorphism. © The Meteoritical Society, 2016. 2016 10.1111/maps.12736 Meteoritics and Planetary Science 51 2441-2458 Saalbau Weltraum Projekt, Wilhelmstrasse 38, Heppenheim, 64646, Germany; Museum für Naturkunde—Leibniz Institute for Evolution and Biodiversity Science, Invalidenstrasse 43, Berlin, 10115, Germany; Bruker-Nano GmbH, Am Studio 2D, Berlin, 12489, Germany; GeoSpectral Imaging, Office E6 Block E, Somerset Office Estate, 604 Kudu Street, Allens Nek, Johannesburg, 1737, South Africa; Department of Geology, University of Johannesburg, PO Box 524, Auckland Park, Johannesburg, 2006, South Africa; Centre de Recherches Pétrographiques et Géochimiques, CRPG UMR 7358 CNRS-UL, 15 rue Notre Dame des Pauvres, Vandœuvre les Nancy, 54500, France; Institut für Erd und Umweltwissenschaften, Universität Potsdam, Karl-Liebknecht-Str. 24-25, Potsdam-Golm, 14476, Germany; Department of Lithospheric Research, University of Vienna, Althanstrasse 14, Vienna, 1090, Austria; Institut für Geologische Wissenschaften, Freie Universität Berlin (FU Berlin), Malteserstrasse 74-100, Berlin, D-12249, Germany; Natural History Museum, Burgring 7, Vienna, 1010, Austria 12 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84990866317&doi=10.1111%2fmaps.12736&partnerID=40&md5=3619380019ac2201d6de67f714f91807 cited By 14 J. Fritz R. Tagle L. Ashworth R.T. Schmitt A. Hofmann B. Luais P.D. Harris D. Hoehnel S. Özdemir T. Mohr-Westheide C. Koeberl article Fritz20162441 A Paleoarchean impact spherule-bearing interval of the 763 m long International Continental Scientific Drilling Program (ICDP) drill core BARB5 from the lower Mapepe Formation of the Fig Tree Group, Barberton Mountain Land (South Africa) was investigated using nondestructive analytical techniques. The results of visual observation, infrared (IR) spectroscopic imaging, and micro-X-ray fluorescence (μXRF) of drill cores are presented. Petrographic and sedimentary features, as well as major and trace element compositions of lithologies from the micrometer to kilometer-scale, assisted in the localization and characterization of eight spherule-bearing intervals between 512.6 and 510.5 m depth. The spherule layers occur in a strongly deformed section between 517 and 503 m, and the rocks in the core above and below are clearly less disturbed. The μXRF element maps show that spherule layers have similar petrographic and geochemical characteristics but differences in (1) sorting of two types of spherules and (2) occurrence of primary minerals (Ni-Cr spinel and zircon). We favor a single impact scenario followed by postimpact reworking, and subsequent alteration. The spherule layers are Al2O3-rich and can be distinguished from the Al2O3-poor marine sediments by distinct Al-OH absorption features in the short wave infrared (SWIR) region of the electromagnetic spectrum. Infrared images can cover tens to hundreds of square meters of lithologies and, thus, may be used to search for Al-OH-rich spherule layers in Al2O3-poor sediments, such as Eoarchean metasediments, where the textural characteristics of the spherule layers are obscured by metamorphism. © The Meteoritical Society, 2016. Article 2016 English 10869379 10.1111/maps.12736 Meteoritics and Planetary Science 51 University of Arkansas 2441 – 2458 12 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84990866317&doi=10.1111%2fmaps.12736&partnerID=40&md5=3619380019ac2201d6de67f714f91807 Cited by: 14; All Open Access, Bronze Open Access Jörg Fritz Roald Tagle Luisa Ashworth Ralf Thomas Schmitt Axel Hofmann Béatrice Luais Phillip D. Harris Desirée Hoehnel Seda Ozdemir Tanja Mohr-Westheide Christian Koeberl article Hopp2016 We present the first comprehensive noble gas study on eclogites. The four eclogite samples were recovered during the Chinese Continental Scientific Drilling and are from two distinct profile depth sections differing in their degree of interaction with meteoric water, based on their δ18O-values (surface related and of mantle-type). Hence, noble gas analyses offer the potential to further discriminate between shallow (meteoric) and deep (mantle) fluid sources. Noble gas compositions reveal typical crustal fluid compositions, characterized by a variable mixture of atmospheric gases with significant contributions of nucleogenic neon, radiogenic 4He*, radiogenic 40Ar*, fissiogenic 131–136Xe, and presumably bariogenic 131Xe, but no significant addition of mantle gases. This signature can be also considered to represent one endmember component of eclogitic diamonds. Concentrations of non-radiogenic noble gases are rather low, with depletion of light relative to the heavier noble gases. Eclogites from lower depth which experienced a higher degree of interaction with meteoric water also showed higher contributions of atmospheric gas compared with eclogites recovered from greater depth. This is interpreted to result from interaction with high-salinity fluids during ultrahigh pressure (UHP). It demonstrates that the atmospheric noble gas abundance is a proxy for interaction with surface related fluids. 40Ar/39Ar (inverse) isochron ages of two phengite separates (241.2 ± 0.4 Ma and 275.0 ± 1.8 Ma, 1σ-errors) predate the main phase of UHP metamorphism (ca. 220 Ma). Biotite yields an integrated age of about 1100 Ma. These age values are interpreted to reflect the likely addition of excess 40Ar without any chronological meaning. © 2016, Springer-Verlag Berlin Heidelberg. Article 2016 English 00107999 10.1007/s00410-016-1290-4 Contributions to Mineralogy and Petrology 171 Springer Verlag 10 argon-argon dating; chemical composition; Chinese Continental Scientific Drilling Project; concentration (composition); eclogite; fluid composition; meteoric water; noble gas; ultrahigh pressure metamorphism https://www.scopus.com/inward/record.uri?eid=2-s2.0-84984911020&doi=10.1007%2fs00410-016-1290-4&partnerID=40&md5=cc5c5861951e31295f1496cb2fdcb078 Cited by: 1 Jens Hopp Winfried H. Schwarz Mario Trieloff Hans-Peter Meyer Michael Hanel Rainer Altherr article Stockhecke201677 Millennial to orbital-scale rainfall changes in the Mediterranean region and corresponding variations in vegetation patterns were the result of large-scale atmospheric reorganizations. In spite of recent efforts to reconstruct this variability using a range of proxy archives, the underlying physical mechanisms have remained elusive. Through the analysis of a new high-resolution sedimentary section from Lake Van (Turkey) along with climate modeling experiments, we identify massive droughts in the Eastern Mediterranean for the past four glacial cycles, which have a pervasive link with known intervals of enhanced North Atlantic glacial iceberg calving, weaker Atlantic Meridional Overturning Circulation and Dansgaard-Oeschger cold conditions. On orbital timescales, the topographic effect of large Northern Hemisphere ice sheets and periods with minimum insolation seasonality further exacerbated drought intensities by suppressing both summer and winter precipitation. © 2015 Elsevier Ltd. 2016 English 02773791 10.1016/j.quascirev.2015.12.016 Quaternary Science Reviews 133 Elsevier Ltd 77-95 Large Lakes Observatory, University of Minnesota Duluth, 10 University Drive 206 RLB, Duluth, MN 55812-2496, United States; Geological Institute, Swiss Federal Institute of Technology (ETH), Sonneggstrasse 5, Zürich, 8092, Switzerland; Eawag, Swiss Federal Institute of Aquatic Science and Technology, Department of Surface Waters Research and Management, Überlandstrasse 133, Dübendorf, 8600, Switzerland; IPRC, and Department of Oceanography, SOEST, University of Hawaii, 1680 East-West Road, Honolulu, HI 96822, United States; Eawag, Swiss Federal Institute of Aquatic Science and Technology, Department of Water Resources and Drinking Water, Überlandstrasse 133, Dübendorf, 8600, Switzerland; Institute of Biogeochemistry and Pollutant Dynamics, Swiss Federal Institute of Technology (ETH), Universitätstrasse 16, Zürich, 8092, Switzerland; Institute of Geochemistry and Petrology, Swiss Federal Institute of Technology (ETH), Clausiusstrasse 25, Zürich, 8092, Switzerland; Ruhr-University Bochum, Universitätsstrasse 150, Bochum, 44801, Germany; CCRC, University of New South Wales, Matthews Building Level 4, Sydney, NSW 2052, Australia; ARC Centre of Excellence for Climate System Science, Australia; Steinmann Institute of Geology, Mineralogy and Paleontology, Bonn University, Nussallee 8, Bonn, 53115, Germany; Institute of Geological Sciences, University of Bern, Baltzerstrasse 1+3, Bern, 3012, Switzerland; Oeschger Centre for Climate Change Research (OCCR), University of Bern, Switzerland Glacial geology; Lakes; Sea ice, Atlantic meridional overturning circulations; Atmospheric reorganization; Dansgaard-Oeschger variability; Eastern Mediterranean; ICDP PALEOVAN; Insolation seasonality; Lake vans; Milankovitch cycle, Drought, climate change; climate modeling; Dansgaard-Oeschger cycle; drought; ice sheet; iceberg calving; Last Glacial-Interglacial; Mediterranean environment; Northern Hemisphere; paleoclimate; precipitation (climatology); seasonality; sediment analysis, Atlantic Ocean; Atlantic Ocean (North); Lake Van; Turkey https://www.scopus.com/inward/record.uri?eid=2-s2.0-84952838092&doi=10.1016%2fj.quascirev.2015.12.016&partnerID=40&md5=2da3181f03ab58af613e18a2aba2313c cited By 68 M. Stockhecke A. Timmermann R. Kipfer G.H. Haug O. Kwiecien T. Friedrich L. Menviel T. Litt N. Pickarski F.S. Anselmetti article Knott20161121 The 1.95-km-thick Cassia Formation, defined in the Cassia Hills at the southern margin of the Snake River Plain, Idaho, consists of 12 refined and newly described rhyolitic members, each with distinctive field, geochemical, mineralogical, geochronological, and paleomagnetic characteristics. It records voluminous high-temperature, Snake River-type explosive eruptions between ca. 11.3 Ma and ca. 8.1 Ma that emplaced intensely welded rheomorphic ignimbrites and associated ash-fall layers. One ignimbrite records the ca. 8.1 Ma Castleford Crossing eruption, which was of supereruption magnitude (~1900 km3). It covers 14,000 km2 and exceeds 1.35 km thickness within a subsided, proximal caldera-like depocenter. Majorand trace-element data define three successive temporal trends toward less-evolved rhyolitic compositions, separated by abrupt returns to more-evolved compositions. These cycles are thought to reflect increasing mantle- derived basaltic intraplating and hybridization of a midcrustal region, coupled with shallower fractionation in upper-crustal magma reservoirs. The onset of each new cycle is thought to record renewed intraplating at an adjacent region of crust, possibly as the North American plate migrated westward over the Yellowstone hotspot. A regional NE-trending monocline, here termed the Cassia monocline, was formed by synvolcanic deformation and subsidence of the intracontinental Snake River basin. Its structural and topographic evolution is reconstructed using thickness variations, offlap relations, and rheomorphic transport indicators in the successive dated ignimbrites. The subsidence is thought to have occurred in response to incremental loading and modification of the crust by the mantle-derived basaltic magmas. During this time, the area also underwent NW-trending faulting related to opening of the western Snake River rift and E-W Basin and Range extension. The large eruptions probably had different source locations, all within the subsiding basin. The proximal Miocene topography was thus in marked contrast to the more elevated present-day Yellowstone plateau. © 2016 Geological Society of America. 2016 English 00167606 10.1130/B31324.1 Bulletin of the Geological Society of America 128 Geological Society of America 1121-1146 Department of Geology, University of Leicester, Leicester, LE1 7RH, United Kingdom; Earth and Planetary Science Department, University of California, Santa Cruz, CA 95064, United States; Quaternary Dating Laboratory, Natural History Museum of Denmark, University of Copenhagen, Copenhagen, 2100, Denmark; Scottish Universities Environmental Research Centre, East Kilbride, G75 0QF, United Kingdom; Department of Geosciences, Idaho State University, Pocatello, ID 83209, United States 7 Explosives; Geochronology; Subsidence; Trace elements, Explosive eruption; Explosive volcanism; Miocene topography; North american plates; Snake river plains; Thickness variation; Transport indicators; Yellowstone hotspot, Rivers, explosive volcanism; geochemistry; geochronology; mineralogy; Miocene; paleomagnetism; rhyolite; subsidence; hot spot; ignimbrite; trace element; volcanology, Idaho; Snake River Plain; United States; Wyoming; Yellowstone Caldera https://www.scopus.com/inward/record.uri?eid=2-s2.0-84977485066&doi=10.1130%2fB31324.1&partnerID=40&md5=9c1e1b32a2e212549be4f86d3d2d4572 cited By 25 T.R. Knott M.J. Branney M.K. Reichow D.R. Finn R.S. Coe M. Storey D. Barfod M. McCurry article Janssen201662 We have examined microstructures, mineralogical composition, geochemical alteration, and texture of four selected fault rock samples from the Deep Geodynamical Laboratory (DGLab) Gulf of Corinth project using optical microscopy, cathodoluminescence microscopy (CL), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and synchrotron X-ray diffraction measurements. The fault core is composed of red and gray clayey gouge material and surrounded by a damage zone of brecciated limestones. Pressure solution features, calcite veins and calcite clasts in the breccia and gouge material attest the presence of paleo-fluids and fluid-driven mass transfer during deformation. Differences in CL-colors between the matrix and calcite vein cement and inside the vein cement suggest repeated infiltration of fluids with different composition from various sources (formation water and meteoric water). Twin lamellae densities estimated in calcite veins are used as paleo-piezometer. The deduced differential stress is ~140 ± 70 MPa for the older vein generation and appears to be higher than stress for the youngest veins (45 ± 23 MPa). In spite of the relatively small clay content in both samples, newly formed clay minerals have been observed in gray as well as red clayey gouge material. Differences between gray and red clay gouge material are found in fault rock composition, porosity and clay fabric. The proportion of chlorite in the red gouge is significantly less than that in the gray gouge whereas the initial porosity is significantly higher than in the gray gouge material. The detection of a well-oriented clay fabric in red clay gouge samples is unique in comparison to other major fault zones. © 2016 Elsevier Ltd. Article 2016 English 01918141 10.1016/j.jsg.2016.03.008 Journal of Structural Geology 86 Elsevier Ltd 62 – 74 Gulf of Corinth; Ionian Sea; Mediterranean Sea; Calcite; Cements; Electron microscopy; High resolution transmission electron microscopy; Mass transfer; Microstructure; Porosity; Rocks; Scanning electron microscopy; Stainless steel; Transmission electron microscopy; X ray diffraction; Clay fabrics; Dissolution precipitations; EBSD; Fault rock; Fluid-rock interaction; Gulf of Corinth; Microstructure analysis; core analysis; deformation mechanism; dissolution; fault slip; fault zone; faulting; microstructure; precipitation (chemistry); stress field; water-rock interaction; Structural geology https://www.scopus.com/inward/record.uri?eid=2-s2.0-84962521294&doi=10.1016%2fj.jsg.2016.03.008&partnerID=40&md5=3b0cb26d3af92c6b050e8d3dfd62eb94 Cited by: 9; All Open Access, Bronze Open Access C. Janssen H.-R. Wenk R. Wirth L. Morales H. Kemnitz J. Sulem G. Dresen conference Wuestefeld20162765 The demand on the versatility of microseismic monitoring networks is increasing rapidly. In early projects, being able to locate any triggers was considered a success. These early successes lead to a better understanding of how to extract value from microseismic results. Operators, regulators, and service providers must work closely together to find the optimum network design to meet various requirements. In this article we discuss three aspects that are of concern in the design phase of modern microseismic monitoring networks: 1) Detection Limits; 2) Location accuracy; 3) Ground-motion hazard. We determine the location error using both conventional "phase-picking" inversion scheme, and a novel method, based on Point Spread functions, to evaluate the accuracy "migration-style" location schemes. Using the well-documented example region around the San Andreas Fault Observatory at Depth (SAFOD) located north of Parkfield, California, we present several approaches to these sometimes competing requirements. Modelling these parameters prior to installation of a sensor network, helps to identify the potential challenges to meet the survey objectives and thus appropriate changes to the design can be implemented. We use the detailed velocity model of Thurber et al. (2004) which covers an area of 26.2x21.2km around the SAFOD drill site with a resolution of 200m for both P-and S-wave velocity (Figure 1). We are modelling the performance of several hypothetical sensor networks within the area. To highlight the importance of using the correct velocity model, we then compare these performance predictions with those for a simplistic 1D velocity model, commonly the only available source of velocity for hydraulic fracturing projects. © 2016 SEG. 2016 English 10523812 10.1190/segam2016-13944667.1 SEG Technical Program Expanded Abstracts 35 Society of Exploration Geophysicists Sicking C., FergusonSicking J. 2765-2769 NORSAR, Norway https://www.scopus.com/inward/record.uri?eid=2-s2.0-85019083452&doi=10.1190%2fsegam2016-13944667.1&partnerID=40&md5=1b5348fb371b5ca7c61dada74da5fff1 cited By 0 A. Wuestefeld T. Kaschwich K. Iranpour article Thomas2016118 A study of an International Continental Drilling Program core recovered from the middle of the modern Dead Sea has identified microbial traces within this subsurface hypersaline environment. A comparison with an active microbial mat exhibiting similar evaporative processes characterized iron-sulphur mineralization and exopolymeric substances resulting from microbial activity. Exopolymeric substances were identified in the drilled sediment but unlike other hypersaline environments, it appears that they have a limited effect on the precipitation of calcium carbonate in the sedimentary column. Sulphate reduction, however, plays a role in all types of evaporative facies, leading to the formation of diagenetic iron sulphides in glacial and interglacial intervals. Their synthesis seems to occur under progressive sulphidation that generally stops at greigite because of incomplete sulphate reduction. The latter may be caused by a lack of suitable organic matter in this hypersaline, hence energy-demanding, environment. Pyrite may be found in periods of high lake productivity, when more labile organic matter is available. The carbon and sulphur cycles are thus influenced by microbial activity in the Dead Sea environment and this influence results in diagenetic transformations in the deep sediment. © 2016 The Authors. The Depositional Record published by John Wiley & Sons Ltd on behalf of International Association of Sedimentologists. 2016 English 20554877 10.1002/dep2.16 Depositional Record 2 John Wiley and Sons Inc 118-138 Department of Earth Sciences, University of Geneva, rue des Maraichers 13, Geneva, CH 1205, Switzerland; Institute of Earth Sciences, Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat Ram, Jerusalem, IL 91904, United States; Lamont-Doherty Earth Observatory, Columbia University, 61 Rt. 9W, Palisades, NY 10964, United States; Geological Survey of Israel, 30 Malkhe Israel St., Jerusalem, IL 95501, United States; UMR 42 CARRTEL, Alpine Research Center on Lake Food Webs, University of Savoie Mont-Blanc, Le Bourget du Lac, 73376, France 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85027698601&doi=10.1002%2fdep2.16&partnerID=40&md5=e4ccb2e03f5c40a42825b769e1b86fe1 cited By 12 C. Thomas Y. Ebert Y. Kiro M. Stein D. Ariztegui techreport eriksson_methods_2016 2016 SKB report R-16-09 p 61 SKB report R-16-09 p 61 http://www.skb.com/publication/2484526/R-16-09.pdf Lena Eriksson Johanna Edlund Linda Johansson Lisa Rabe Andreas Bengtsson Karsten Pedersen article Cao2016866 The Songliao Basin is the largest non-marine oil-bearing basin in China. Due to the absence of sufficient evidence, the hypothesis of seawater incursion(s) into the Songliao Basin remains controversial. Marine fossil materials can provide direct explanations. More recently, a few calcareous nannofossils were discovered from units 1 and 2 of the Nenjiang Formation in drill hole SK-1. In these fossils, some taxa have been positively identified, namely Calculites obscurus, Calculites ovalis, Quadrum sp., and Micula sp. They were distributed in marine environment of the Cretaceous. Based on comparisons of the calcareous nannofossil assemblages from global records, the age of units 1 of the Nenjiang Formation seems to have spanned from the latest Turonian to Maastrichtian. The nannofossils from the Songliao Basin have the marine origin, characterized by common diversity and abundance. The distribution and paleoecology of the calcareous nannofossils as well as the co-existing foraminifera in the SK-1 provide further evidence for seawater incursion events in the Songliao Basin. The authors hold that periodical seawater incursion(s) brought calcareous nannofossils and foraminifera into the Songliao Basin during sedimentation of units 1 and 2 of the Nenjiang Formation, when both lake and sea were at high level. © 2016, Science Press. All right reserved. Article 2016 Chinese 16712552 Geological Bulletin of China 35 China Geological Survey 866 – 871 6 China; Nen Basin; Songliao Basin; Calculites (nannofossil); Foraminifera; Micula; abundance; Cretaceous; foraminifera; fossil assemblage; geological record; marine environment; nanofossil; paleoecology; seawater; sedimentation; species diversity https://www.scopus.com/inward/record.uri?eid=2-s2.0-84976508989&partnerID=40&md5=ea378728952c50257d0b52db0ac7ffa6 Cited by: 4 Wenxin Cao Dangpeng Xi Qinghua Huang Yi Cheng Haiying Qu Lianfeng Gao Xiaoqiao Wan article Batten201640 The composite SK-1 borehole drilled in the Songliao Basin, north-east China penetrated non-marine rocks of Late Cretaceous age, some of which yielded assemblages of Ghoshispora. Species of this megaspore genus have palaeoenvironmental and potentially also biostratigraphic significance. Their value as determinants of age is, however, currently limited because many are difficult if not impossible to differentiate as our appraisal of their morphological characters reveals. This review helped to put the specimens recovered from the SK-1 borehole into context and led to the identification of a few of the specimens as Ghoshispora kondinskayae (Srivastava et Binda) Srivastava, G. sp. cf. G. bella (Kondinskaya) subsp. deltoidea Kutluk et al., and G. sp. cf. G. rara (Kondinskaya) Srivastava. Several revealed characters under the scanning electron microscope that differ from those of previously published species: two of these are described as new, namely Ghoshispora zhaoi sp. nov. and G. bulbosa sp. nov. Owing to a lack of sufficient specimens six other morphotypes have had to be identified in open nomenclature as G. sp. A-F. It is likely that the parent plants of all of the species grew in and/or close to standing water. The comparatively large number of very small specimens in association with, and having some of the characters of, the larger representatives of G. zhaoi suggests that a few might be the microspores of this species rather than incompletely developed megaspores. © 2016 Elsevier B.V. 2016 English 00346667 10.1016/j.revpalbo.2016.05.001 Review of Palaeobotany and Palynology 232 Elsevier B.V. 40-60 Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing, 210008, China; School of Earth, Atmospheric and Environmental Sciences, The University of Manchester, Oxford Road, Manchester, M13 9PL, United Kingdom; Department of Geography and Earth Sciences, Aberystwyth University, Penglais, Aberystwyth, SY23 3DB, United Kingdom; University of Chinese Academy of Sciences, Beijing, 100049, China biogenic deposit; biostratigraphy; Cretaceous; fern; fossil assemblage; geographical distribution; identification method; morphology; morphotype; nomenclature; paleoenvironment; palynology; scanning electron microscopy; spore; taxonomy, China; Songliao Basin https://www.scopus.com/inward/record.uri?eid=2-s2.0-84973367361&doi=10.1016%2fj.revpalbo.2016.05.001&partnerID=40&md5=f96e6682ed08d6ff83df7545b8802330 cited By 3 D.J. Batten J. Li J. Peng article Wilke2016118 Sedimentary sequences in ancient or long-lived lakes can reach several thousands of meters in thickness and often provide an unrivalled perspective of the lake's regional climatic, environmental, and biological history. Over the last few years, deep-drilling projects in ancient lakes became increasingly multi- and interdisciplinary, as, among others, seismological, sedimentological, biogeochemical, climatic, environmental, paleontological, and evolutionary information can be obtained from sediment cores. However, these multi- and interdisciplinary projects pose several challenges. The scientists involved typically approach problems from different scientific perspectives and backgrounds, and setting up the program requires clear communication and the alignment of interests. One of the most challenging tasks, besides the actual drilling operation, is to link diverse datasets with varying resolution, data quality, and age uncertainties to answer interdisciplinary questions synthetically and coherently. These problems are especially relevant when secondary data, i.e., datasets obtained independently of the drilling operation, are incorporated in analyses. Nonetheless, the inclusion of secondary information, such as isotopic data from fossils found in outcrops or genetic data from extant species, may help to achieve synthetic answers. Recent technological and methodological advances in paleolimnology are likely to increase the possibilities of integrating secondary information. Some of the new approaches have started to revolutionize scientific drilling in ancient lakes, but at the same time, they also add a new layer of complexity to the generation and analysis of sediment-core data. The enhanced opportunities presented by new scientific approaches to study the paleolimnological history of these lakes, therefore, come at the expense of higher logistic, communication, and analytical efforts. Here we review types of data that can be obtained in ancient lake drilling projects and the analytical approaches that can be applied to empirically and statistically link diverse datasets to create an integrative perspective on geological and biological data. In doing so, we highlight strengths and potential weaknesses of new methods and analyses, and provide recommendations for future interdisciplinary deep-drilling projects. © 2016 Elsevier B.V. Review 2016 English 09218181 10.1016/j.gloplacha.2016.05.005 Global and Planetary Change 143 Elsevier B.V. 118 – 151 Biology; Geology; Paleolimnology; Analytical approach; Ancient lakes; Deep drilling; Evolutionary biology; Evolutionary information; Interdisciplinary project; Methodology; Sedimentary sequence; biological survey; core analysis; data quality; deep drilling; evolutionary biology; fossil record; geological theory; integrated approach; lacustrine environment; outcrop; paleolimnology; technological change; Lakes https://www.scopus.com/inward/record.uri?eid=2-s2.0-84975523752&doi=10.1016%2fj.gloplacha.2016.05.005&partnerID=40&md5=65b5fcf6cccc099d292cd51ee6749ff8 Cited by: 26; All Open Access, Bronze Open Access, Green Open Access Thomas Wilke Bert Van Bocxlaer Christian Albrecht Daniel Ariztegui Diana Delicado Alexander Francke Mathias Harzhauser Torsten Hauffe Jens Holtvoeth Janna Just Zlatko Levkov Kirsty Penkman Laura Sadori Alister Skinner Björn Stelbrink Hendrik Vogel Frank Wesselingh Thomas Wonik article Steinmann2016361 To date, the origin of the Campi Flegrei caldera is still under debate and may be related to (1) a single caldera collapse associated with the Neapolitan Yellow Tuff (NYT) eruption, (2) two subsequent caldera collapses associated with the NYT and the preceding Campanian Ignimbrite (CI) eruptions forming a nested-caldera complex, or (3) not related to a caldera collapse after all. Here, we study the submerged portion of the caldera, which has favored a marine depositional setting and, thus, represents an ideal location for the reconstruction of its formation history, utilizing multichannel seismic data. Volcanic deposits and edifices were seismically distinguished from sedimentary successions, and the stratigraphy could be refined and extended back to the Campanian Ignimbrite eruption at ~ 39 ka. High-resolution multichannel reflection seismic data revealed the existence of a nested-caldera complex formed during the CI eruption at ~ 39 ka and the more recent NYT eruption at ~ 15 ka. A ring-fault bounding an inner caldera collapse structure was clearly imaged. It appears that this inner ring-fault was initially activated during the CI caldera collapse and later reactivated during the NYT caldera collapse with different amounts of subsidence. The NYT caldera probably formed during an asymmetrical collapse with a maximum subsidence of ~ 75 m in the offshore portion. The vertical displacement related to the CI caldera collapse may be significantly larger. The submerged caldera depression accommodates post-eruption sediments. Within this high-resolution archive, two major unconformities developed at ~ 8.6 ka and 5 ka, when resurgence-related uplift exceeded the rate of sea-level rise concurrent with the emersion of the La Starza terrace. A previously unknown post-collapse submarine volcanic mound located between Nisida Island and Nisida Bank probably formed between 4.8 and 3.7 ka. Also, the Penta Palummo Bank appears to be constructed of at least two monogenetic volcanic edifices, the Penta Palummo volcano formed at ~ 100 ka and a younger mushroom-shaped unit formed between 39 and 15 ka. The main outcome of this study is a conceptual evolutionary model, providing novel insights on the formation of the Campi Flegrei nested caldera in the course of two large-scale eruptions (CI and NYT) with associated caldera collapses along mutual (i.e. reactivated) faults and subsequent caldera resurgence. As both the genesis and subsurface architecture of the Campi Flegrei caldera are still hotly debated topics in literature, our discoveries can be regarded as a substantial advancement in the understanding of the Campi Flegrei volcanic area. © 2016 Elsevier B.V. Article 2016 English 03770273 10.1016/j.jvolgeores.2016.09.001 Journal of Volcanology and Geothermal Research 327 Elsevier B.V. 361 – 374 Campania [Italy]; Campi Flegrei; Italy; Napoli [Campania]; Basidiomycota; Buildings; Seismic response; Seismic waves; Seismology; Stratigraphy; Subsidence; Volcanoes; Caldera formation; Caldera resurgence; Campi Flegrei; Fault system; Nested calderas; Reflection seismics; caldera; Campanian; collapse; formation mechanism; ignimbrite; landform evolution; sea level change; seismic reflection; volcanic eruption; Sea level https://www.scopus.com/inward/record.uri?eid=2-s2.0-84994493618&doi=10.1016%2fj.jvolgeores.2016.09.001&partnerID=40&md5=82ad66c0f6689dc6393785a35dd14f1c Cited by: 20 Lena Steinmann Volkhard Spiess Marco Sacchi article Sato201636 Positive platinum group element (PGE) concentration and negative Os isotope anomalies reported from a claystone layer in the Upper Triassic bedded chert succession of the Sakahogi section, Mino Belt, central Japan, are thought to have been derived from an impact event. Stratigraphic variations and concentrations of PGE were examined in the Sakahogi section to determine the type of the impactor. Upper Triassic claystone layers, where PGE anomalies have been newly discovered in bedded chert successions in southwest Japan, were also examined. These include (i) the Unuma section in the Inuyama area, Mino Belt; (ii) the Hisuikyo section in the Kamiaso area, Mino Belt; and (iii) the Enoura section in the Tsukumi area, Chichibu Belt. Radiolarian and conodont biostratigraphic data indicate that these claystone layers are of upper-middle Norian age. Reconstruction of bedded chert in these sections suggests that they originate from open-ocean pelagic deep-sea sediments deposited in the Panthalassa Ocean.The relatively flat CI chondrite-normalized patterns of the least mobile PGEs (Ir, Ru, and Rh) and the Ru/Ir ratio determined by linear regression analysis suggest that a chondritic impactor is the source of the PGE anomalies preserved in claystone samples from the study sections. Although Ru/Ir ratios cannot conclusively distinguish chondrites from iron meteorites, the Cr/Ir ratios of the claystone layers range from 104 to 105, clearly indicating contribution from chondritic materials. The chondritic impactor of the suggested size (3.3-7.8km in diameter) implies that a large amount of debris and/or climatically active gasses (e.g., sulfur oxides) would have been released from the impactor, which would have had a marked effect on the environment. © 2015 Elsevier B.V. 2016 10.1016/j.palaeo.2015.11.015 Palaeogeography, Palaeoclimatology, Palaeoecology 442 36-47 Department of Earth and Planetary Sciences, Kyushu University, Fukuoka, 812-8581, Japan; Department of Chemistry, Tokyo Metropolitan University, Tokyo, 192-0397, Japan; Department of Earth and Environmental Sciences, Kumamoto University, Kumamoto, 860-8555, Japan; Japan Agency for Marine-Earth Science and Technology, Yokosuka, 237-0061, Japan https://www.scopus.com/inward/record.uri?eid=2-s2.0-84949239143&doi=10.1016%2fj.palaeo.2015.11.015&partnerID=40&md5=3a2efff68d43dd82735e4860f06014db cited By 8 H. Sato N. Shirai M. Ebihara T. Onoue S. Kiyokawa article DeNatale20164836 The 501 m deep hole of the Campi Flegrei Deep Drilling Project, located west of the Naples metropolitan area and inside the Campi Flegrei caldera, gives new insight to reconstruct the volcano-tectonic evolution of this highly populated volcano. It is one of the highest risk volcanic areas in the world, but its tectonic structure, eruptive history, and size of the largest eruptions are intensely debated in the literature. New stratigraphic and 40Ar/39Ar geochronological dating allow us to determine, for the first time, the age of intracaldera deposits belonging to the two highest magnitude caldera-forming eruptions (i.e., Campanian Ignimbrite, CI, 39 ka, and Neapolitan Yellow Tuff, NYT, 14.9 ka) and to estimate the amount of collapse. Tuffs from 439 m of depth yield the first 40Ar/39Ar age of ca. 39 ka within the caldera, consistent with the CI. Volcanic rocks from the NYT were, moreover, detected between 250 and 160 m. Our findings highlight: (i) a reduction of the area affected by caldera collapse, which appears to not include the city of Naples; (ii) a small volume of the infilling caldera deposits, particularly for the CI, and (iii) the need for reassessment of the collapse amounts and mechanisms related to larger eruptions. Our results also imply a revaluation of volcanic risk for the eastern caldera area, including the city of Naples. The results of this study point out that large calderas are characterized by complex collapse mechanisms and dynamics, whose understanding needs more robust constraints, which can be obtained from scientific drilling. © 2016. The Authors. Article 2016 English 15252027 10.1002/2015GC006183 Geochemistry, Geophysics, Geosystems 17 Blackwell Publishing Ltd 4836 – 4847 12 Campania [Italy]; Campi Flegrei; Italy; Naples; Napoli [Campania]; Deposits; Geochronology; Hazards; Stratigraphy; Tectonics; Volcanic rocks; Caldera-forming eruption; Campanian Ignimbrite; Campi Flegrei; Collapse mechanism; Neapolitan yellow tuffs; Scientific drilling; Tectonic structure; Volcanic hazards; argon-argon dating; caldera; deep drilling; geochronology; reconstruction; tectonic evolution; volcanic eruption; Volcanoes https://www.scopus.com/inward/record.uri?eid=2-s2.0-85006489601&doi=10.1002%2f2015GC006183&partnerID=40&md5=2d497bf52ab196d9681f4bf2f4c6a8ff Cited by: 55; All Open Access, Hybrid Gold Open Access Giuseppe De Natale Claudia Troise Darren Mark Angela Mormone Monica Piochi Mauro A. Di Vito Roberto Isaia Stefano Carlino Diana Barra Renato Somma article Lindhorst2016291 Lake Ohrid (LO), a transboundary lake shared by Macedonia and Albania on the Balkan Peninsula, is not only considered to be the oldest lake in Europe (~2 Ma) but has a long and continuous sedimentary history. An advantage at LO is the availability of hydroacoustic data sets of good quality covering the entire lake basin. The tectonically formed basin is filled with thick undisturbed sediments. However, the overall internal structure of LO is characterized by numerous faults, clinoform structures, and several Mass Transport Deposits (MTDs). By using a seismic chronology model (SCM) correlating seismic reflector packages with Marine Isotope Stages (MIS) we estimate the occurrence of the deepest MTD detected in the southern basin at the transition of MIS9 to MIS8 (~300 ka) defining the onset of the sliding history in LO that is still ongoing today. In general, MTDs are widespread within the basin but they do cluster at active faults. Two large MTDs occurred in the early MIS7 (~230 ka, ~220 ka) and after a quiesence period of about ~70 ka two additional large MTDs have been detected in the late penultimate glacial period MIS6 (~150 ka, 130 ka). MIS5 seemed to be another quiet period with respect to mass wasting. In the younger sedimentary history mass movement is a common process with several large and mid-sized deposits mapped at all stratigraphic levels. The youngest slide deposits are estimated to occur within the last 2,000 years. The main outcome of this paper is a model for the spatial and temporal distribution of mass wasting for Lake Ohrid. © Springer International Publishing Switzerland 2016. 2016 English 18789897 10.1007/978-3-319-20979-1_29 Advances in Natural and Technological Hazards Research 41 Springer Netherlands 291-300 Institute of Geosciences, Christian-Albrechts-University at Kiel, Kiel, Germany; Leibniz- Institute for Applied Geophysics (LIAG), Stilleweg 2, Hannover, 30655, Germany https://www.scopus.com/inward/record.uri?eid=2-s2.0-85013993530&doi=10.1007%2f978-3-319-20979-1_29&partnerID=40&md5=fb03dcaa38b908c9bb32bc55db6e7c95 cited By 2 H. Baumgarten article McLing2016144 A map of groundwater temperatures from the Eastern Snake River Plain (ESRP) regional aquifer can be used to identify and interpret important features of the aquifer, including aquifer flow direction, aquifer thickness, and potential geothermal anomalies. The ESRP is an area of high heat flow, yet most of this thermal energy fails to reach the surface, due to the heat being swept downgradient by the aquifer to the major spring complexes near Thousand Springs, ID, a distance of 300 km. Nine deep boreholes that fully penetrate the regional aquifer display three common features: (1) high thermal gradients beneath the aquifer, corresponding to high conductive heat flow in low-permeability hydrothermally-altered rocks; (2) isothermal temperature profiles within the aquifer, characteristic of an actively flowing groundwater; and (3) moderate thermal gradients in the vadose zone with values that indicate that over half of the geothermal heat flow is removed by advective transport in the regional aquifer system. This study utilized temperature data from 250 ESRP aquifer wells to evaluate regional aquifer flow direction, aquifer thickness, and potential geothermal anomalies. Because the thermal gradients are typically low in the aquifer, any measurement of groundwater temperature is a reasonable estimate of temperature throughout the aquifer thickness, allowing the construction of a regional aquifer temperature map for the ESRP. Mapped temperatures are used to identify cold thermal plumes associated with recharge from tributary valleys and adjacent uplands, and warm zones associated with geothermal input to the aquifer. Warm zones in the aquifer can have various causes, including local circulation of groundwater through the deep conductively dominated region, slow groundwater movement in low-permeability regions, or localized heat flow from deeper thermal features. © 2015 Elsevier B.V. 2016 English 03770273 10.1016/j.jvolgeores.2016.04.006 Journal of Volcanology and Geothermal Research 320 Elsevier B.V. 144-155 Idaho National Laboratory, P.O. Box 1625, Idaho Falls, ID 83415-2107, United States; The Center for Advanced Energy Studies, 995 University Blvd, Idaho Falls, ID 83401, United States; Smith Geologic and Photographic Services, LLC, Nathrop, CO 81236, United States; University of Idaho, Moscow, ID 83844, United States; Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM 87545, United States Aquifers; Boreholes; Geothermal energy; Geothermal heating; Groundwater; Groundwater flow; Heat transfer; Rivers; Temperature distribution; Thermal gradients, Advective transport; Geothermal potential; Ground water movement; Groundwater temperatures; Hydrothermally altered rocks; Isothermal temperature; Snake river plains; Thermal groundwater, Groundwater resources, aquifer; flow modeling; groundwater; heat flow; permeability; temperature profile; tracer, Idaho; Snake River Plain; United States, Calluna vulgaris https://www.scopus.com/inward/record.uri?eid=2-s2.0-84965053138&doi=10.1016%2fj.jvolgeores.2016.04.006&partnerID=40&md5=05fdc3b4dcecd0d63439ee1e025113fd cited By 9 T.L. McLing R.P. Smith R.W. Smith D.D. Blackwell R.C. Roback A.J. Sondrup article López-Merino201649 Lacustrine laminated sediments are often varves representing annual rhythmic deposition. The Dead Sea high-stand laminated sections consist of mm-scale alternating detrital and authigenic aragonite laminae. Previous studies assumed these laminae were varves deposited seasonally. However, this assumption has never been robustly validated. Here we report an examination of the seasonal deposition of detrital-aragonite couplets from two well-known Late Holocene laminated sections at the Ze'elim fan-delta using palynology and grain-size distribution analyses. These analyses are complemented by the study of contemporary flash-flood samples and multivariate statistical analysis. Because transport affects the pollen preservation state, well-preserved (mostly) air-borne transported pollen was analysed separately from badly-preserved pollen and fungal spores, which are more indicative of water transport and reworking from soils. Our results indicate that (i) both detrital and aragonite laminae were deposited during the rainy season; (ii) aragonite laminae have significantly lower reworked and fungal spore concentrations than detrital and flash-flood samples; and (iii) detrital laminae are composed of recycling of local and distal sources, with coarser particles that were initially deposited in the Dead Sea watershed and later transported via run-off to the lake. This is in line with previous carbon balance studies that showed that aragonite precipitation occurs after the massive input of TCO2 associated with run-off episodes. Consequently, at least for the Holocene Ze'elim Formation, laminated sediments cannot be considered as varves. Older Quaternary laminated sequences should be re-evaluated. © 2016 The Authors. 2016 English 02773791 10.1016/j.quascirev.2016.03.024 Quaternary Science Reviews 140 Elsevier Ltd 49-66 Institute of Environment, Health and Societies, Brunel University London, Uxbridge, UB8 3PH, United Kingdom; The Ted Arisson Airborne Allergens Monitoring Laboratory, Tel Aviv University, Tel Aviv, 69978, Israel; Dr Strauss Department of Marine Geosciences, Charney School of Marine Sciences, University of Haifa, Mount Carmel, Haifa, 31905, Israel Deposition; Floods; Fungi; Grain size and shape; Multivariant analysis; Particle size analysis; Seawater; Sediments, Air borne; Aragonite; Dead sea; Flash flood; Laminated sediments; Reworked pollen, Carbonate minerals, aragonite; carbon balance; flash flood; fungus; Holocene; lacustrine deposit; lamination; palynology; reworking; runoff; spore; varve; watershed, Dead Sea https://www.scopus.com/inward/record.uri?eid=2-s2.0-84961990942&doi=10.1016%2fj.quascirev.2016.03.024&partnerID=40&md5=9ac261d56af1ef441f3ed47e008cad30 cited By 21 L. López-Merino S.A.G. Leroy A. Eshel V. Epshtein R. Belmaker R. Bookman article Hockun2016110 When using biomarkers such as n-alkanes as tools for paleo-environmental reconstructions, it is imperative to determine their specific sources for each setting. Toward that goal, we analyzed a set of various potential organic matter (OM) sources such as aquatic and terrestrial plants, dust, and soils from Laguna Potrok Aike (LPA) and surrounding areas in southern Patagonia. We determined chain length distributions and hydrogen (δD) and carbon (δ13C) isotopic compositions of n-alkanes of different OM sources in order to quantify their relative contributions to lake sediments. Our results reveal that the mid-chain n-alkane, n-C23, is predominantly produced by submerged aquatic plants, whereas long-chain n-alkanes (n-C29–n-C31) are derived from various terrestrial sources. We estimated their relative contributions to the sediment using two approaches, i.e., based on the n-alkane distributions and their δD and δ13C values. Both approaches result in similar estimates of aquatic and terrestrial contributions for mid- and long-chain n-alkanes to the sediment. 62–73% of the mid-chain n-C23 alkanes originate from aquatic sources while 66–77% of the long-chain n-alkanes originate from dust and 14–30% from terrestrial plants. Our study shows that mid-chain n-alkanes such as the n-C23 alkane in LPA are derived mainly from aquatic macrophytes and thus have the potential to record changes in lake-water isotopic composition. In contrast, the n-C29 alkane reflects the isotopic signal of various terrestrial sources from southern Patagonia. © 2016 Elsevier Ltd Article 2016 10.1016/j.orggeochem.2016.10.001 Organic Geochemistry 102 110 – 119 Argentina; Laguna Potrok Aike; Patagonia; Santa Cruz [Argentina]; Biogeochemistry; Biological materials; Chains; Dust; Isotopes; Lakes; Sediments; Chain length distribution; Environmental reconstruction; ICDP; Isotopic composition; Long chain n-alkanes; n-Alkanes; PASADO; Relative contribution; alkane; biomarker; carbon isotope; hydrogen isotope; isotopic composition; lacustrine deposit; macrophyte; organic matter; paleoenvironment; reconstruction; sediment chemistry; spatial distribution; stable isotope; submerged vegetation; Paraffins https://www.scopus.com/inward/record.uri?eid=2-s2.0-84995752879&doi=10.1016%2fj.orggeochem.2016.10.001&partnerID=40&md5=8f884b34ac3a22c04773cd469bed5ce6 Cited by: 25; All Open Access, Green Open Access Katja Hockun Gesine Mollenhauer Sze Ling Ho Jens Hefter Christian Ohlendorf Bernd Zolitschka Christoph Mayr Andreas Lücke Enno Schefuß article Fallick2016224 A variety of carbonates of different geneses, as indicated by petrography and geochemistry, are found throughout 400 m of the volcano-sedimentary rocks of the Zaonega Formation of Palaeoproterozoic age in the Onega basin of Fennoscandia. Following intensive sampling and analysis of varied calcites from drillcore recovered during the ICDP FAR-DEEP program, we report a highly unusual depth distribution of calcite oxygen isotope values (δ18Ocal). Unprecedentedly for such rocks, the δ18Ocal values over the full depth interval of 400 m are strongly linearly correlated with depth (r2 = 0.9015, n = 178). We propose that this is the result of major oxygen isotope resetting through water–rock interaction with a fluid of relatively constant oxygen isotopic composition (δ18Ow). In this model, the observed linear δ18Ocal-depth relationship is then a consequence of the increase in temperature with depth because of the background geothermal gradient. Minor deviations from the overall linear trend are likely due to bed-scale geological factors including locally high impermeability, and oxygen isotope modification of δ18Ow by comparatively intense water–rock interaction. Were the observed δ18Ocal values to have been reset during the greenschist facies Svecofennian metamorphism which affected the rocks at c. 1800 Ma, the implied geothermal gradient of ∼560 °C km−1 is geologically unreasonable and, accordingly, this hypothesis is ruled out. Rather, the δ18Ocal variation of 5‰ over 400 m implies a near-surface depth for the rocks during fluid interaction, and this is consistent with a surface-derived origin of the infiltrating fluid (δ18Ow ∼−13.6‰ for a surface temperature of 15 °C and geothermal gradient of ∼52 °C km−1). It is speculated that the fluid accessed the carbonates from the basin edge by bed-parallel rather than cross-formational flow. There is an intriguing distribution of Na in the sedimentary rocks of the Zaonega Formation. Sodium is relatively abundant in rocks below a certain depth (the lowermost dolostone at ∼258 m), but rare in shallower sequences. It is argued that this distribution did not originate with the basin-scale fluid–rock interaction documented above, but may rather be the result of evaporite dissolution, and subsequent redistribution of soluble elements during fluid flow associated with the syndepositional emplacement of basin-wide igneous rocks. © 2016 Elsevier B.V. Article 2016 English 03019268 10.1016/j.precamres.2016.06.001 Precambrian Research 281 Elsevier B.V. 224 – 235 Isotope Geosciences Unit, SUERC, Rankine Avenue, East Kilbride G75 0QF, Scotland, United Kingdom; Norwegian Geological Survey, Leif Eirikssons vei 39, Trondheim, N-4791, Norway; School of Geosciences, Meston Building, University of Aberdeen, Old Aberdeen AB24 3UE, Scotland, United Kingdom; Department of Earth and Environmental Sciences, St. Andrews University, St. Andrews, Fife KY16 9ALScotland, United Kingdom calcite; carbonate; diagenesis; geothermal gradient; oxygen isotope; Proterozoic; water-rock interaction, Arkhangelsk [Russian Federation]; Fennoscandia; Onega Basin; Russian Federation https://www.scopus.com/inward/record.uri?eid=2-s2.0-84991641456&doi=10.1016%2fj.precamres.2016.06.001&partnerID=40&md5=b9507d0407235e6ff3cec62dade7994a Cited by: 6 A.E. Fallick V.A. Melezhik A.T. Brasier A.R. Prave article Tofilovska2016218 Lake Ohrid is the oldest existing lake in Europe and it is known for its high diversity with around 200 endemic or relict diatom species recognized. In order to understand this phenomenon, a large project on deep drilling was performed and a core with maximum sediment depth of 569 m which spans > 1.2 million years was recovered. Two new species of Cyclotella were discovered in the core samples, which are described here as Cyclotella cavitata sp. nov. and Cyclotella sollevata sp. nov. The species have been studied with light and scanning electron microscopes, their morphological features and their relevance to other members of the genus Cyclotella are discussed. Cyclotella cavitata sp. nov. is characterized by round to elliptical shape; elliptic and tangentially undulate central area with one to three papillae on the elevated side. Central fultoportulae are absent while marginal fultoportulae internally are located on slightly depressed costae, with short tube openings with two satellite pores surrounded by cowlings. Satellite pores are situated circumferentially. Internally the rimoportula is situated in the marginal area with a sessile labium. Cyclotella sollevata sp. nov. is characterized by round valves with convex or concave central area which is uneven, colliculate, with papillae and granules. Central fultoportulae are present with variable number (9-21), internally with short tube openings with two satellite pores, which are surrounded by cowlings; Internally marginal fultoportulae are located on depressed costae and have short tube openings with two satellite pores situated circumferentially, surrounded by cowlings. The rimoportulae are located in the marginal area with a sessile labium variably orientated. Cyclotella sollevata and Cyclotella cavitata have been observed only in the fossil sediments of Lake Ohrid. Comments on the position of rimoportula, used as synapomorphic character to separate Lindavia from Cyclotella sensu lato are provided. © Czech Phycological Society (2016). Article 2016 English 18025439 10.5507/fot.2016.003 Fottea 16 Czech phycological Society 218 – 233 2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84991581714&doi=10.5507%2ffot.2016.003&partnerID=40&md5=bbab30568ce2fbc9ac4285e25ea65748 Cited by: 4; All Open Access, Bronze Open Access Slavica Tofilovska Aleksandra Cvetkoska Elena Jovanovska Nadja Ognjanova-Rumenova Zlatko Levkov article Kruse2016101 Siberian boreal forests are expected to expand northwards in the course of global warming. However, processes of the treeline ecotone transition, as well astiming and related climate feedbacks are still not understood. Here, we present ‘Larix Vegetation Simulator’ LAVESI, an individual-based spatially-explicit model that can simulate Larix gmelinii (Rupr.) Rupr. stand dynamics in an attempt to improve our understanding about past and future treeline movements under changing climates. The relevant processes (growth, seed production and dispersal, establishment and mortality) are incorporated and adjusted to observation data mainly gained from the literature. Results of a local sensitivity analysis support the robustness of the model's parameterization by giving relatively small sensitivity values. We tested the model by simulating tree stands under modern climate across the whole Taymyr Peninsula, north-central Siberia (c. 64–80° N; 92–119° E). We find tree densities similar to observed forests in the northern to mid-treeline areas, but densities are overestimated in the southern parts of the simulated region. Finally, from a temperature-forcing experiment, we detect that the responses of tree stands lag the hypothetical warming by several decades, until the end of 21st century. With our simulation experiments we demonstrate that the newly-developed model captures the dynamics of the Siberian latitudinal treeline. © 2016 2016 English 03043800 10.1016/j.ecolmodel.2016.08.003 Ecological Modelling 338 Elsevier B.V. 101-121 Department of Periglacial Research, Alfred-Wegener-Institute, Helmholtz Centre for Polar and Marine Research (AWI), Potsdam, D-14473, Germany; Institute of Biochemistry and Biology, University of Potsdam, Potsdam-Golm, D-14476, Germany; Institute of Earth and Environmental Science, University of Potsdam, Potsdam-Golm, D-14476, Germany; ZALF, Leibniz-Centre for Agricultural Landscape Research, Eberswalder Str. 84, MünchebergD-15374, Germany; Berlin-Brandenburg Institute of Advanced Biodiversity Research (BBIB), Berlin, D-14195, Germany Climate models; Dynamics; Ecology; Global warming; Sensitivity analysis, Forest change; Individual based model; Larix gmelinii; Local sensitivity analysis; Model description; Sensitivity values; Spatially explicit modeling; Time-lag effect, Forestry, boreal forest; climate change; climate effect; coniferous forest; ecological modeling; ecotone; experimental study; forest ecosystem; global warming; literature review; permafrost; sensitivity analysis; treeline; twenty first century, Krasnoyarsk [Russian Federation]; Russian Federation; Siberia; Taymyr Peninsula, Larix; Larix gmelinii https://www.scopus.com/inward/record.uri?eid=2-s2.0-84982124884&doi=10.1016%2fj.ecolmodel.2016.08.003&partnerID=40&md5=b399d76eff4e75554604c1bc270c6251 cited By 28 S. Kruse M. Wieczorek F. Jeltsch U. Herzschuh article Mohan2016235 Paleolake Hadar was an expansive lake in the lower Awash Valley of Ethiopia’s Afar Depression that existed periodically through the Late Pliocene. The sedimentary deposits from this ancient lake (Hadar Formation) have broad importance because a significant number of hominin fossils have been recovered from the formation. Samples of the Hadar Formation lacustrine sequence were collected from sediment cores extracted as part of the Hominin Sites and Paleolakes Drilling Project (HSPDP). A paleoecological study of the HSPDP Northern Awash (Hadar Formation) material has unearthed three novel species of Bacillariophyta (diatoms) from diatomites that appear periodically in the cores. The Hadar Formation assemblage represents a newly revealed excerpt from the evolutionary history of freshwater diatoms in East Africa during the Piacenᴢian age (2.59-3.60 Ma). The HSPDP Northern Awash diatom species are compared to previously reported diatoms from Pliocene outcrops, modern and fossil core material from Lake Malawi, and extant species. Here we describe two new species of Aulacoseira and one of Lindavia. Taxonomic treatment of two diatom varieties reported by previous researchers as Melosira are transferred into Aulacoseira herein. © 2016 Magnolia Press. Article 2016 English 11793155 10.11646/phytotaxa.272.4.1 Phytotaxa 272 Magnolia Press 235 – 247 4 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84986882133&doi=10.11646%2fphytotaxa.272.4.1&partnerID=40&md5=5e89066f36e08b6d660e155cfc38ffc2 Cited by: 2; All Open Access, Bronze Open Access Joseph Mohan Jeffery R. Stone Christopher J. Campisano article Mahabadi20163099 The water retention curve and relative permeability are critical to predict gas and water production from hydrate-bearing sediments. However, values for key parameters that characterize gas and water flows during hydrate dissociation have not been identified due to experimental challenges. This study utilizes the combined techniques of micro-focus X-ray computed tomography (CT) and pore-network model simulation to identify proper values for those key parameters, such as gas entry pressure, residual water saturation, and curve fitting values. Hydrates with various saturation and morphology are realized in the pore-network that was extracted from micron-resolution CT images of sediments recovered from the hydrate deposit at the Mallik site, and then the processes of gas invasion, hydrate dissociation, gas expansion, and gas and water permeability are simulated. Results show that greater hydrate saturation in sediments lead to higher gas entry pressure, higher residual water saturation, and steeper water retention curve. An increase in hydrate saturation decreases gas permeability but has marginal effects on water permeability in sediments with uniformly distributed hydrate. Hydrate morphology has more significant impacts than hydrate saturation on relative permeability. Sediments with heterogeneously distributed hydrate tend to result in lower residual water saturation and higher gas and water permeability. In this sense, the Brooks-Corey model that uses two fitting parameters individually for gas and water permeability properly capture the effect of hydrate saturation and morphology on gas and water flows in hydrate-bearing sediments. © 2016. American Geophysical Union. All Rights Reserved. 2016 English 15252027 10.1002/2016GC006372 Geochemistry, Geophysics, Geosystems 17 Blackwell Publishing Ltd 3099-3110 School of Sustainable Engineering and the Built Environment, Arizona State University, Tempe, AZ, United States; School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, GA, United States; National Energy Technology Laboratory, Morgantown, WV, United States; Department of Civil and Environmental Engineering, Yonsei University, Seoul, South Korea 8 Computerized tomography; Curve fitting; Dissociation; Flow of water; Gas permeability; Gases; Hydration; Hydraulics; Morphology; Sediments, Brooks-Corey model; Hydrate bearing sediments; Pore-network modeling; Relative permeability; Van Genuchten model; Water retention curve, Gas hydrates, gas hydrate; gas production; hydrocarbon reservoir; numerical model; permeability; porosity; water retention https://www.scopus.com/inward/record.uri?eid=2-s2.0-84982803665&doi=10.1002%2f2016GC006372&partnerID=40&md5=c33fb617e8266ead9dd1030b8bbee488 cited By 114 N. Mahabadi S. Dai Y. Seol T. Sup Yun J. Jang article mangwegape2016sr 2016 Journal of African Earth Sciences 113 Elsevier 95--100 Mpho Mangwegape Frederick Roelofse Timothy Mock Richard W Carlson article Darlington20162416 The Lawn Hill Impact Structure (LHIS) is located 250 km N of Mt Isa in NW Queensland, Australia, and is marked by a highly deformed dolomite annulus with an outer diameter of ~18 km, overlying low metamorphic grade siltstone, sandstone, and shale, along the NE margin of the Georgina Basin. This study provides detailed field observations from sections of the Lawn Hill annulus and adjacent areas that demonstrate a clear link between the deformation of the dolomite and the Lawn Hill impact. 40Ar-39Ar dating of impact-related melt particles provides a time of impact in the Ordovician (472 ± 8 Ma) when the Georgina Basin was an active depocenter. The timing and stratigraphic thickness of the dolomite sequence in the annulus suggest that there was possibly up to 300 m of additional sedimentary rocks on top of the currently exposed Thorntonia Limestone at the time of impact. The exposed annulus is remarkably well preserved, with preservation attributed to postimpact sedimentation. The LHIS has an atypical crater morphology with no central uplift. The heterogeneous target materials at Lawn Hill were probably low-strength, porous, and water-saturated, with all three properties affecting the crater morphology. The water-saturated nature of the carbonate unit at the time of impact is thought to have influenced the highly brecciated nature of the annulus, and restricted melt production. The impact timing raises the possibility that the Lawn Hill structure may be a member of a group of impacts resulting from an asteroid breakup that occurred in the mid-Ordovician (470 ± 6 Ma). © The Meteoritical Society, 2016. 2016 10.1111/maps.12734 Meteoritics and Planetary Science 51 2416-2440 College of Science and Engineering, James Cook University, Townsville, QLD, Australia; School of Earth and Ocean Science, Cardiff University, Cardiff, United Kingdom; School of Geosciences, Monash University, Melbourne, VIC, Australia 12 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84992359610&doi=10.1111%2fmaps.12734&partnerID=40&md5=4709c73cd17046ae21c56c4b730cfae3 cited By 13 V. Darlington T. Blenkinsop P. Dirks J. Salisbury A. Tomkins article Cohen20161 The role that climate and environmental history may have played in influencing human evolution has been the focus of considerable interest and controversy among paleoanthropologists for decades. Prior attempts to understand the environmental history side of this equation have centered around the study of outcrop sediments and fossils adjacent to where fossil hominins (ancestors or close relatives of modern humans) are found, or from the study of deep sea drill cores. However, outcrop sediments are often highly weathered and thus are unsuitable for some types of paleoclimatic records, and deep sea core records come from long distances away from the actual fossil and stone tool remains. The Hominin Sites and Paleolakes Drilling Project (HSPDP) was developed to address these issues. The project has focused its efforts on the eastern African Rift Valley, where much of the evidence for early hominins has been recovered.We have collected about 2 km of sediment drill core from six basins in Kenya and Ethiopia, in lake deposits immediately adjacent to important fossil hominin and archaeological sites. Collectively these cores cover in time many of the key transitions and critical intervals in human evolutionary history over the last 4 Ma, such as the earliest stone tools, the origin of our own genus Homo, and the earliest anatomically modern Homo sapiens. Here we document the initial field, physical property, and core description results of the 2012-2014 HSPDP coring campaign. © Author(s) 2016. Article 2016 English 18168957 10.5194/sd-21-1-2016 Scientific Drilling 21 Copernicus GmbH 1 – 16 Core drilling; Deposits; Drills; Environmental protection; Lakes; Sediments; Archaeological site; Drilling projects; Environmental contexts; Environmental history; Evolutionary history; Human evolution; Lake deposits; Paleoclimatic record; Deepwater drilling https://www.scopus.com/inward/record.uri?eid=2-s2.0-84958769593&doi=10.5194%2fsd-21-1-2016&partnerID=40&md5=353363f454af8d712dc228049c649085 Cited by: 72; All Open Access, Gold Open Access, Green Open Access A. Cohen C. Campisano R. Arrowsmith A. Asrat A.K. Behrensmeyer A. Deino C. Feibel A. Hill R. Johnson J. Kingston H. Lamb T. Lowenstein A. Noren D. Olago R.B. Owen R. Potts K. Reed R. Renaut F. Schäbitz J.J. Tiercelin M.H. Trauth J. Wynn S. Ivory K. Brady R. O'Grady J. Rodysill J. Githiri J. Russell V. Foerster R. Dommain S. Rucina D. Deocampo A. Billingsley C. Beck G. Dorenbeck L. Dullo D. Feary D. Garello R. Gromig T. Johnson A. Junginger M. Karanja E. Kimburi A. Mbuthia T. McCartney E. McNulty V. Muiruri E. Nambiro E.W. Negash D. Njagi J.N. Wilson N. Rabideaux T. Raub M.J. Sier P. Smith J. Urban M. Warren M. Yadeta C. Yost B. Zinaye article Menzies2016125 Fluids play a key role in modifying the chemical and physical properties of fault zones, which may prime them for repeated rupture by the generation of high pore fluid pressures and precipitation of commonly weak, secondary minerals. Fluid flow paths, sources and fluxes, and the permeability evolution of fault zones throughout their seismic cycles remain poorly constrained, despite their importance to understanding fault zone behaviour. Here we use geochemical tracers of fluid-rock exchange to determine budgets for meteoric, metamorphic and mantle fluids on a major compressional tectonic plate boundary.The Alpine Fault marks the transpressional Pacific-Australian plate boundary through South Island, New Zealand and appears to fail in regular (329±68 yrs) large earthquakes (Mw~8) with the most recent event in 1717 AD. Significant convergent motion has formed the Southern Alps and elevated geothermal gradients in the hangingwall, which drive crustal fluid flow. Along the Alpine Fault the Alpine Schist of the Pacific Plate is thrust over radiogenic metasedimentary rocks on the Australian plate. The absence of highly radiogenic (87Sr/86Sr &gt; 0.7200) strontium isotope ratios of hangingwall hot springs and hydrothermal minerals formed at a range of depths in the Alpine Fault damage zone indicates that the fluid flow is restricted to the hangingwall by a cross-fault fluid flow barrier throughout the seismogenic crust. Helium isotope ratios measured in hot springs near to the Alpine Fault (0.15-0.81 RA) indicate the fault is a crustal-scale feature that acts as a conduit for fluids from the mantle. Rock-exchanged oxygen, but meteoric water-like hydrogen isotope signatures of hydrothermal veins indicate that partially rock-exchanged meteoric fluids dominate down to the top of the brittle to ductile transition zone at ∼6 km. Geochemical tracer transport modelling suggests only ∼0.02 to 0.05% of total rainfall west of the Main Divide penetrates to depth, yet this recharge flux is sufficient to overwhelm other fluid contributions. Calculated mantle fluid fluxes of CO2 and H2O (0.2 and 3 to 13 mol/m2/yr respectively) and metamorphic H2O fluxes (4 to 750 mol/m2/yr) are considerably lower than the focused meteoric water discharge flux up the Alpine Fault (4 × 103 to 7 × 104 mol/m2/yr), driven by the &gt;3000 m hydrologic head of the Southern Alps. Meteoric waters are primarily responsible for modifying fault zone permeability during fluid-rock interactions and may facilitate the generation of high pore fluid pressures that could assist episodic earthquake rupture. © 2016 The Authors. 2016 English 0012821X 10.1016/j.epsl.2016.03.046 Earth and Planetary Science Letters 445 Elsevier B.V. 125-135 Ocean and Earth Science, National Oceanography Centre Southampton, University of SouthamptonSO14 3ZH, United Kingdom; Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences, Telegrafenberg, Potsdam, 14473, Germany; GNS Science, Private Bag 1930, Dunedin, 9054, New Zealand; Department of Geology, University of Otago, Dunedin, 9016, New Zealand Budget control; Carbon dioxide; Earthquakes; Faulting; Flow of fluids; Geochemistry; Geochronology; Geophysics; Helium; Hot springs; Isotopes; Metamorphic rocks; Rocks, Alpine Faults; Fault seal; Fluid fluxes; Helium isotopes; Mantle CO2; Meteoric waters, Transport properties, carbon dioxide; earthquake magnitude; earthquake rupture; fault zone; helium isotope; mantle source; meteoric water; Pacific plate; permeability; plate boundary, Alpine Fault Zone; New Zealand; South Island https://www.scopus.com/inward/record.uri?eid=2-s2.0-84979724290&doi=10.1016%2fj.epsl.2016.03.046&partnerID=40&md5=79c9aac287264e600c45011f9336af07 cited By 38 C.D. Menzies D.A.H. Teagle S. Niedermann S.C. Cox D. Craw M. Zimmer M.J. Cooper J. Erzinger article Puchtel20162168 Article 2016 10.1002/2016GC006324 Geochemistry, Geophysics, Geosystems 17 2168 – 2193 6 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84977541987&doi=10.1002%2f2016GC006324&partnerID=40&md5=4418a515b19f4d81585d07e8a773f454 Cited by: 109; All Open Access, Green Open Access Igor S. Puchtel Janne Blichert-Toft Mathieu Touboul Mary F. Horan Richard J. Walker article Schultze2016323 Impact melt rocks from the 1.9 km diameter, simple bowl-shaped Tenoumer impact crater in Mauritania have been analyzed chemically and petrologically. They are heterogeneous and can be subdivided into three types based on melt matrix color, occurrence of lithic clast components, amount of vesiculation (melt degassing), different proportions of carbonate melt mingled into silicate melt, and bulk rock chemical composition. These heterogeneities have two main causes (1) due to the small size of the impact crater, there was probably no coherent melt pool where a homogeneous mixture of melts, derived from different target lithologies, could be created; and (2) melt rock heterogeneity occurring at the thin section scale is due to fast cooling during and after the dynamic ejection and emplacement process. The overall period of crystal growth from these diverse melts was extremely short, which provides a further indication that complete chemical equilibration of the phases could not be achieved in such short time. Melt mixing processes involved in the generation of impact melts are, thus, recorded in nonequilibrium growth features. Variable mixing processes between chemically different melt phases and the formation of hybrid melts can be observed even at millimeter scales. Due to extreme cooling rates, different mixing and mingling stages are preserved in the varied parageneses of matrix minerals and in the mineral chemistry of microlites. 40Ar39Ar step-heating chronology on specimens from three melt rock samples yielded five concordant inverse isochron ages. The inverse isochron plots show that minute amounts of inherited 40Ar* are present in the system. We calculated a weighted mean age of 1.57 ± 0.14 Ma for these new results. This preferred age represents a refinement from the previous range of 21 ka to 2.5 Ma ages based on K/Ar and fission track dating. © 2016 The Meteoritical Society. 2016 10.1111/maps.12593 Meteoritics and Planetary Science 51 323-350 Museum für Naturkunde-Leibniz-Institute of Evolution and Biodiversity Research, Invalidenstrasse 43, Berlin, 10115, Germany; Technische Universität Berlin, Institut für Mineralogie-Petrologie, Ackerstrasse 76, Berlin, 13355, Germany; JdL Centre and Department of Applied Geology, Curtin University-Western Australian Argon Isotope Facility, GPO Box U1987, Perth, WA 6845, Australia; Humboldt Universität zu Berlin, Unter den Linden 6, Berlin, 10099, Germany 2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84957960639&doi=10.1111%2fmaps.12593&partnerID=40&md5=e010e496e497fe2ed43a58af654eb926 cited By 12 D.S. Schultze F. Jourdan L. Hecht W.U. Reimold R.-T. Schmitt article Francke20161179 Lake Ohrid (Macedonia, Albania) is thought to be more than 1.2 million years old and host more than 300 endemic species. As a target of the International Continental scientific Drilling Program (ICDP), a successful deep drilling campaign was carried out within the scope of the Scientific Collaboration on Past Speciation Conditions in Lake Ohrid (SCOPSCO) project in 2013. Here, we present lithological, sedimentological, and (bio-)geochemical data from the upper 247.8 m composite depth of the overall 569 m long DEEP site sediment succession from the central part of the lake. According to an age model, which is based on 11 tephra layers (first-order tie points) and on tuning of bio-geochemical proxy data to orbital parameters (second-order tie points), the analyzed sediment sequence covers the last 637 kyr. The DEEP site sediment succession consists of hemipelagic sediments, which are interspersed by several tephra layers and infrequent, thin (< 5 cm) mass wasting deposits. The hemipelagic sediments can be classified into three different lithotypes. Lithotype 1 and 2 deposits comprise calcareous and slightly calcareous silty clay and are predominantly attributed to interglacial periods with high primary productivity in the lake during summer and reduced mixing during winter. The data suggest that high ion and nutrient concentrations in the lake water promoted calcite precipitation and diatom growth in the epilimnion during MIS15, 13, and 5. Following a strong primary productivity, highest interglacial temperatures can be reported for marine isotope stages (MIS) 11 and 5, whereas MIS15, 13, 9, and 7 were comparably cooler. Lithotype 3 deposits consist of clastic, silty clayey material and predominantly represent glacial periods with low primary productivity during summer and longer and intensified mixing during winter. The data imply that the most severe glacial conditions at Lake Ohrid persisted during MIS16, 12, 10, and 6, whereas somewhat warmer temperatures can be inferred for MIS14, 8, 4, and 2. Interglacial-like conditions occurred during parts of MIS14 and 8. © Author(s) 2016. Article 2016 English 17264170 10.5194/bg-13-1179-2016 Biogeosciences 13 Copernicus GmbH 1179 – 1196 Institute of Geology and Mineralogy, University of Cologne, Cologne, Germany; Leibniz Institute for Applied Geophysics (LIAG), Hannover, Germany; Institute of Geological Sciences, Oeschger Centre for Climate Change Research, University of Bern, Bern, Switzerland; Centre for Environmental Geochemistry, School of Geography, University of Nottingham, Nottingham, United Kingdom; NERC Isotope Geosciences Facilities, British Geological Survey, Keyworth, Nottingham, United Kingdom; Dipartimento di Biologia Ambientale, Università di Roma La Sapienza, Rome, Italy; Dipartimento di Scienze della Terra, University of Pisa, Pisa, Italy; Dipartimento di Scienze della Terra e Geoambientali, University of Bari, Bari, Italy; Istituto per la Dinamica dei Processi Ambientali (IDPA) CNR, Milan, Italy; Istituto di Geologia Ambientale e Geoingegneria - CNR, Rome, Italy 4 Albania; Greece; Lake Ohrid; Macedonia [Greece]; Bacillariophyta; calcite; deep drilling; diatom; endemic species; epilimnion; geochemistry; lacustrine environment; lithotype; marine isotope stage; pelagic deposit; precipitation (chemistry); primary production; seasonal variation; silty clay; tephra https://www.scopus.com/inward/record.uri?eid=2-s2.0-84959333193&doi=10.5194%2fbg-13-1179-2016&partnerID=40&md5=5665be7f73c59b1c89582f78c0e9abf1 Cited by: 86; All Open Access, Gold Open Access, Green Open Access Alexander Francke Bernd Wagner Janna Just Niklas Leicher Raphael Gromig Henrike Baumgarten Hendrik Vogel Jack H. Lacey Laura Sadori Thomas Wonik Melanie J. Leng Giovanni Zanchetta Roberto Sulpizio Biagio Giaccio article Wang201682 Recent ICDP drilling and deep basin volcanic exploration of 3000 m below the surface in the Songliao Basin (SB) have highlighted the 3-D delineation of the basin. The integrated new data led us to reevaluate the basin tectonics, for which the basin type, basin evolution and a number of geodynamic aspects have been controversial topics. We outline the position of a main lithospheric scale detachment fault beneath the SB, based on apparent crustal scale displacements, Moho breaks, the thinning of the Moho transition zone beneath the SB and the changing mantle thickness. This fault interpretation is consistent with simple shear as the rift mechanism. Based on a comprehensive analysis of the tectonic setting, underlying crust, structural style, sequence stratigraphy, subsidence history and volcanism, we propose an active continental margin model for the SB which shows some similarities to aulacogens but also notable differences. Situated between two Late Mesozoic active continental margins, the northern/northwestern Mongol-Okhotsk and the eastern Sikhote-Alin orogenic belts, the Cretaceous basin evolved on a pre-Triassic structurally weak basement mosaic. Its development began with regional mega-rifting from 150 to 105 Ma, followed by significant sagging between 105 and 79.1 Ma and ended with regional uplift and basin inversion from 79.1 to 64 Ma. Three regional angular unconformities separate the basin fill into three respective tectono-stratigraphic sequences. (1) The syn-rift stage is characterized by widespread fault-bounded grabens and volcanogenic successions, corresponding upward to the Huoshiling, Shahezi and Yingcheng Formations. (2) The post-rift stage includes the Denglouku, Quantou, Qignshankou, Yaojia and Nenjiang Formations. It is a special feature that the subsidence rate is abnormally high (mean of 103 m/Ma), and that flood basalt erupted along an axial wrench fault zone, associated with several marine intervals from the mid-Turonian to early Campanian (K2qn to K2n), possibly (not certainly) indicating incipient sea floor spreading characterized by Moho breaks along the basin axis in the SB around 88 Ma. Stretching stopped abruptly at approximately 79.1 Ma and was followed by uplift and rapid erosion (-145 m/Ma). (3) Recorded by the Sifangtai and Mingshui Formations the structural inversion stage included a continuous depocenter migration to the northwest. The basin was shrinking to demise as a result of changing subduction parameters of the Pacific subduction zone. In addition to the three tectonic basin cycles, a cyclic basin fill pattern exists with three volcanic basin fill intervals of Huoshiling, Yingcheng, and upper Qingshankou Formations that alternate with sedimentary basin fill intervals of Shahezi, Dengloukou-Quantou, and Yaojia-Nenjiang Formations.When determining the subsidence rates, we observed not only anomalously fast subsidence but also found an intricate link between the subsidence rate and type of basin fill. After each volcanic interval, the subsidence rates increased in a cyclic fashion during the sedimentary intervals. Thus, there is a system of three different types of important, basin-wide geological cycles that controlled the evolution of the SB. The subsidence rate was especially high (up to 199 m/Ma) after the last volcanic episode at 88 Ma. In addition to thermal subsidence and loading by the basin fill as causative processes, we also consider magmatic processes related to asthenospheric upwelling beneath the SB. They involve the roof collapse of shallow, depleted magma chambers, the igneous accretion of initially hot, dense, basic rocks, and lithospheric delamination beneath the SB. The difference in the subsidence rates during the volcanic and sedimentary intervals may in part also have been due to heating-related uplift during the volcanic intervals. The particularly high subsidence during the Late Cretaceous sedimentary cycles was partly increased by transtension. We put forward a general model for active continental margin basins. They are generally similar to aulacogens but display the following differences. In active continental margin basins, rifting depends on the subduction parameters that may cause strong to mild extension in the giant marginal region. The geochemical composition of the volcanic rocks is more calc-alkaline in nature because they are suprasubduction-related. These basins will eventually enter a post-rift sag stage that involves thermal subsidence. However, the basin will still be near an active continental margin, and, thus, some dip- and/or strike-slip faulting may occur coevally, depending on the subduction parameters. Sag cycles in active continental margin basins will likely include volcanism. Basin inversion will after all affect active continental margin basins. Such basins strike parallel to the respective continental margin. Thus, basin inversion by subduction/collision may be more intense than in the case of aulacogens, which do not tend to strike parallel to the continental margin. Basin inversion may also precede a collision due to changing subduction parameters. Subsidence behavior may also differ because many aspects of subsidence may be at work. Subsidence curves in active continental margin basins may be fairly individual. The application of our model only requires settings with the presence of one Pacific margin type. © 2016 The Authors. 2016 English 00128252 10.1016/j.earscirev.2016.05.004 Earth-Science Reviews 159 Elsevier B.V. 82-102 College of Earth Sciences and Key-Lab for Evolution of Past Life and Environment in NE Asia, Jilin University, Changchun, 130061, China; Department of Earth Science, Sultan Qaboos University, Muscat, Oman; YuA. Kosygin Institute of Tectonics and Geophysics, Far Eastern Branch of Russian Academy of Sciences, Khabarovsk, Russian Federation; Institute of Exploration and Development of Daqing Oilfield Company Ltd., Daqing, 163712, China; Department of Geoscience, University of Wisconsin-Madison, 1215 W. Dayton St., Madison, WI 57706, United States collision zone; continental margin; detachment fault; Moho; Pacific plate; rift zone; subduction; tectonic evolution; tectonic setting; three-dimensional modeling; transition zone, China; Songliao Basin https://www.scopus.com/inward/record.uri?eid=2-s2.0-84971382164&doi=10.1016%2fj.earscirev.2016.05.004&partnerID=40&md5=d04a4531fb4118ece4423a0c524620d4 cited By 149 P.-J. Wang F. Mattern N.A. Didenko D.-F. Zhu B. Singer X.-M. Sun article Montinaro2016177 Sedimentary and magmatic rocks and their distinct sulphur isotopic signatures indicate the sources and processes of sulphur cycling, in particular through the analysis of all four stable sulphur isotopes (32S, 33S, 34S and 36S). Research over the past 15 years has substantially advanced our understanding of sulphur cycling on the early Earth, most notably through the discovery of mass-independently fractionated sulphur isotopic signatures. A strong atmospheric influence on the early Archean global sulphur cycle is apparent, much in contrast to the modern world. Diverse microbially driven sulphur cycling is clearly discernible, but its importance for Earth surface environments remains to be quantified. © 2016 Cambridge University Press. Article 2016 English 14735504 10.1017/S1473550415000531 International Journal of Astrobiology 15 Cambridge University Press 177 – 185 3 Archean; magma; pyrite; sedimentary rock; stable isotope; sulfate; sulfur cycle; sulfur isotope https://www.scopus.com/inward/record.uri?eid=2-s2.0-84962128075&doi=10.1017%2fS1473550415000531&partnerID=40&md5=371e260cceee80debb0954123e5b0492 Cited by: 2 A. Montinaro H. Strauss article Kaldal20161 Flow testing of IDDP-1, the first Icelandic Deep Drilling Project (IDDP) well drilled in the Krafla geothermal field in Iceland, demonstrated promising results by producing superheated steam. During an unavoidable quenching of the well the innermost casing failed presumably due to tensile stresses caused by thermal contraction. Since the structural integrity of casings is essential for utilization of high temperature geothermal wells, the well has not been discharged again. In this paper, the casings of the well are analyzed structurally with a nonlinear finite-element model. The load history of the casings is followed from installation and through several thermal cycles, but the well was discharged at least six times before it was quenched with cold water. The results show that changes in stiffness due to the presence of casing shoes and changes in casing thickness have an effect on the stress and strain formations in neighboring casings. The results illustrate that during each thermal cycle, the wellbore thermal load is more severe for the production casing than for the external casings that are somewhat protected, provided that cementing in between is adequate. © 2016 Elsevier Ltd. 2016 English 03756505 10.1016/j.geothermics.2016.02.002 Geothermics 62 Elsevier Ltd 1-11 Faculty of Industrial Engineering, Mechanical Engineering and Computer Science, University of Iceland, Hjardarhagi 2-6, Reykjavik, IS-107, Iceland Geothermal fields; Geothermal wells; Shoe manufacture; Structural analysis; Thermal cycling, High temperature; IDDP; Krafla geothermal field; Non-linear finite element model; Production casings; Steel casing; Structural modeling; Thermal contraction, Finite element method, finite element method; geothermal energy; geothermal power; numerical model; structural analysis, Iceland https://www.scopus.com/inward/record.uri?eid=2-s2.0-84960351589&doi=10.1016%2fj.geothermics.2016.02.002&partnerID=40&md5=dec1188ca9991a53d47e1a00d851ebfd cited By 14 G.S. Kaldal M.T. Jonsson H. Palsson S.N. Karlsdottir article Wegner20162347 Article 2016 10.1111/maps.12731 Meteoritics and Planetary Science 51 2347 – 2365 12 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84991051789&doi=10.1111%2fmaps.12731&partnerID=40&md5=827eb8005b6736ce25e6c58b13862df5 Cited by: 2; All Open Access, Bronze Open Access Wencke Wegner Christian Koeberl article Powell2016109 Site investigation borehole cores and temporary shaft exposures at the Toll House Pumping Station shaft site, Castle Hill, Scarborough, North Yorkshire, have revealed new data on the Callovian to Lower Oxfordian (Jurassic) succession. The condensed transgressive marine unit, the Lower Callovian Cornbrash Formation, rich in berthierine ooids and abundant shelly fossils, and the attenuated Cayton Clay Formation represent the Early Callovian marine transgression that flooded the low-gradient alluvial plain, which is represented by the underlying Scalby Formation. The Callovian Osgodby Formation (Red Cliff Rock and Langdale members) is an extensively bioturbated, silty sandstone with abundant berthierine-pyrite ooids in the lower part. It was deposited in lower- to upper-shoreface settings. Slow sedimentation rates, with long sediment residence time, resulted in a diverse ichnofauna and a high bioturbation index. Framboidal pyrite ooids in the lower Osgodby Formation sandstones are interpreted as being formed in anoxic lagoons in the nearshore zone; ooids were subsequently swept offshore during storm surge-ebb events. Cold water dinoflagellate cysts of Boreal affinity such as Gonyaulacysta dentata in the lower part of the Oxford Clay Formation indicate an Early Oxfordian age. This is confirmed by the presence of the zonal ammonite species Quenstedoceras mariae and is consistent with a relatively cold, but warming, palaeoclimate at this time. Shaft excavations revealed a new major fault, the Toll House Fault, which is interpreted to be a splay fault bifurcating off the main Castle Hill Fault. Together, the Toll House and Castle Hill faults form the western bounding faults of the Peak Trough, a graben-like structure that extends northwards, offshore.Supplementary material: Supplementary data 1 (Macrofossil identifications from the Toll House shaft) and Supplementary data 2 (List of macropalaeontological specimens from the Toll House Boreholes) are available at https://dx.doi.org/10.6084/m9.figshare.c.3469968. © 2016 The Author(s). Published by The Geological Society of London for the Yorkshire Geological Society. All rights reserved. Article 2016 English 00440604 10.1144/pygs2016-365 Proceedings of the Yorkshire Geological Society 61 Geological Society of London 109 – 133 2 England; North Yorkshire; Scarborough [North Yorkshire]; United Kingdom; Ammonoidea; Dinophyceae; bioturbation; Callovian; Oxfordian; sandstone; sedimentation rate; sedimentology; storm surge; stratigraphy; transgression https://www.scopus.com/inward/record.uri?eid=2-s2.0-84999700147&doi=10.1144%2fpygs2016-365&partnerID=40&md5=70224495142221c3f04f712a83c3899e Cited by: 5; All Open Access, Green Open Access John H. Powell James B. Riding article Moody2016115 Geothermal energy depends on high subsurface temperature, adequate permeability and fracture volume, and accessible groundwater supply to support heat exchange with surrounding rock. Some regions may have adequate thermal resources but lack the necessary permeability or deep circulating water. Exploitation of such areas for geothermal energy could occur if permeability can be enhanced enough to provide the necessary heat exchange. These improvements to the geothermal reservoir would produce what is termed an "enhanced geothermal system" (EGS). The Snake River Plain (SRP) in southern Idaho is a geological region with high heat flux (~110 mW/m2) that has been recommended as an EGS target. In this study, we consider how the geologic and thermal history of the SRP might influence its EGS potential. We describe the fracture distribution (mean = 28.63 fractures/10 m) in a welded tuff core recovered from one of the few deep boreholes located on the SRP and provide a preliminary discussion of the likely geomechanical behavior under in situ stress. Spatial autocorrelation of fracture features is defined with geostatistical techniques and used in a stochastic simulation of possible structures in other welded tuff reservoirs. Autocorrelation scales for the continuous date are on the order of 70 meters with high subsample scale variability (56 m). Results should aid in designing criteria for a hydraulic fracturing plan that would augment the permeability and connectivity of an SRP reservoir's preexisting fracture network. © 2016 The Geological Society of America. All rights reserved. 2016 English 9780813725192 00721077 10.1130/2016.2519(08) Special Paper of the Geological Society of America 519 Geological Society of America Dowling C.B., Florea L.J., Neumann K. 115-136 Department of Geological Sciences, University of Idaho, 875 Perimeter Drive, MS 3022, Moscow, ID 83844, United States; Idaho National Laboratory, Earth Resources Recovery and Sustainability, 2525 Fremont Avenue, Idaho Falls, ID, United States Autocorrelation; Boreholes; Fracture; Geothermal fields; Geothermal wells; Groundwater; Heat exchangers; Heat flux; Hydraulic fracturing; Petroleum reservoir engineering; Stochastic models; Stochastic systems; Welding, Enhanced geothermal systems; Fracture distributions; Geomechanical behavior; Geostatistical techniques; Preexisting fracture; Spatial autocorrelations; Stochastic simulations; Subsurface temperature, Geothermal energy, fracture network; geothermal power; geothermal system; groundwater exploration; heat flux; hydraulic fracturing; permeability; reservoir; surface temperature, Idaho; Idaho; Snake River Plain; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-84971377828&doi=10.1130%2f2016.2519%2808%29&partnerID=40&md5=d964eb00f94fcbdea8329227ccdbfb45 cited By 0 A. Moody J. Fairley M. Plummer article Preuss2016859 Melt degassing by bubble nucleation and growth is a driving mechanism of magma ascent. Therefore, decompression experiments with hydrous silicate melts were used to investigate the onset and the dynamics of H2O degassing. Nominally H2O undersaturated trachytic Campi Flegrei and phonolitic Vesuvius melts representative for the magma compositions of the Campi Flegrei volcanic system were decompressed at a super-liquidus temperature of 1050°C from 200 MPa to final pressures (Pfinal) of 100, 75, and 60 MPa using continuous decompression rates of 0.024 and 0.17 MPa/s. Experiments started from either massive glass cylinders or glass powder to demonstrate the infl of the starting material on melt degassing. Glass powder can be used to shorten the equilibration time (teq) prior to decompression for dissolution of H2O in the melt. The decompressed samples were quenched and compared in terms of bubble number density (NV), porosity, and residual H2O content in the melt. Decompression of all glass cylinder samples led to homogeneous bubble nucleation with high NV of ∼105 mm-3. The supersaturation pressures for homogeneous bubble nucleation were estimated to be <76 MPa for the trachytic and <70 MPa for the phonolitic melt. In contrast to glass cylinders, the usage of glass powder equilibrated for 24 h before decompression prevented homogeneous bubble nucleation during decompression. We suggest that trapped air in the powder pore space resulted in the formation of tiny H2O-N2 bubbles throughout the samples prior to decompression. Degassing of these glass powder samples was facilitated by diffusive growth of these pre-existing bubbles and thus did not require signifi H2O supersaturation of the melt. This is evidenced by several orders of magnitude lower NV and lower residual H2O contents at correspondingly higher porosities compared to the glass cylinder samples. However, a signifi extension of teq to 96 h in the glass powder experiments led to degassing results comparable to the glass cylinder samples. This effect is probably due to Ostwald ripening, coalescence, and the ascent of the pre-existing bubbles during the extended teq prior to decompression. The NV of the glass cylinder samples were used to test the applicability of the vesiculation model provided by Toramaru (2006). For the applied decompression rates, the experimental NV are up to 5 orders of magnitude higher than the values predicted by the model. This may be mainly attributed to the usage of the macroscopic surface tension and the total H2O diffusivity in the model to describe the molecular process of bubble nucleation. A signifi increase in modeled NV can be achieved by application of a reduced surface tension in combination with the lower diffusivity of network formers as a limiting parameter for the formation of a bubble nucleus. This study demonstrates that the investigation of homogeneous bubble nucleation necessitates an optimized experimental protocol. We strongly recommend performing experiments with massive glass cylinders as starting material. The timescale of decompression is a limiting parameter and must be short enough to minimize the opportunity for a reduction of NV by bubble coalescence. Considering our comparably high NV, the samples of many previous experimental studies that were used to calibrate models for homogeneous bubble nucleation were probably subject to signifi NV reduction. Newly derived data from optimized experiments will require improved models for homogeneous bubble nucleation during magma ascent. © 2016 by Walter de Gruyter Berlin/Boston. Article 2016 English 0003004X 10.2138/am-2016-5480 American Mineralogist 101 Walter de Gruyter GmbH 859 – 875 4 Campania [Italy]; Campi Flegrei; Italy; Napoli [Campania]; Vesuvius; Coalescence; Crystallization; Cylinders (shapes); Degassing; Nucleation; Porosity; Silicates; Supersaturation; Surface tension; Bubble nucleation; Bubble number densities; Campi Flegrei; Decompression experiments; Magma ascents; bubble; decompression; degassing; magma; melt; volcanic glass; Glass https://www.scopus.com/inward/record.uri?eid=2-s2.0-84964938395&doi=10.2138%2fam-2016-5480&partnerID=40&md5=7d42fc264aa1439949dc8aa9f0b8e683 Cited by: 19 Oliver Preuss Holger Marxer Sarah Ulmer Wolf Johannes Marcus Nowak article Mortimer201662 The evolution of through-going normal-fault arrays from initial nucleation to growth and subsequent interaction and mechanical linkage is well documented in many extensional provinces. Over time, these processes lead to predictable spatial and temporal variations in the amount and rate of displacement accumulated along strike of individual fault segments, which should be manifested in the patterns of footwall exhumation. Here, we investigate the along-strike and vertical distribution of low-temperature apatite (U–Th)/He (AHe) cooling ages along the bounding fault system, the Livingstone fault, of the Karonga Basin of the northern Malawi Rift. The fault evolution and linkage from rift initiation to the present day has been previously constrained through investigations of the hanging wall basin fill. The new cooling ages from the footwall of the Livingstone fault can be related to the adjacent depocentre evolution and across a relay zone between two palaeo-fault segments. Our data are complimented by published apatite fission-track (AFT) data and reveal significant variation in rock cooling history along-strike: the centre of the footwall yields younger cooling ages than the former tips of earlier fault segments that are now linked. This suggests that low-temperature thermochronology can detect fault interactions along strike. That these former segment boundaries are preserved within exhumed footwall rocks is a function of the relatively recent linkage of the system. Our study highlights that changes in AHe (and potentially AFT) ages associated with the along-strike displacement profile can occur over relatively short horizontal distances (of a few kilometres). This is fundamentally important in the assessment of the vertical cooling history of footwalls in extensional systems: temporal differences in the rate of tectonically driven exhumation at a given location along fault strike may be of greater importance in controlling changes in rates of vertical exhumation than commonly invoked climatic fluctuations. © 2016 Elsevier B.V. 2016 English 0012821X 10.1016/j.epsl.2016.08.040 Earth and Planetary Science Letters 455 Elsevier B.V. 62-72 Institut für Erd- und Umweltwissenschaften Universität Potsdam, Potsdam, Germany; School of Earth and Environment, University of Leeds, Woodhouse Lane, Leeds, United Kingdom; School of Geosciences, University of Edinburgh, West Mains Road, Edinburgh, EH9 3FE, United Kingdom; Isotope Geosciences Unit, Scottish Universities Environmental Research Centre, East Kilbride, Scotland, United Kingdom Apatite; Cooling systems; Fission reactions; Geologic models; Phosphate minerals; Tectonics; Temperature, Apatite fission tracks; Climatic fluctuations; Displacement profiles; East African Rift; Normal faults; Spatial and temporal variation; Thermochronology; Vertical distributions, Fault slips, fault scarp; fault zone; footwall; hanging wall; normal fault; segmentation; spatiotemporal analysis; thermochronology, East African Rift https://www.scopus.com/inward/record.uri?eid=2-s2.0-84992386089&doi=10.1016%2fj.epsl.2016.08.040&partnerID=40&md5=a1759aebc85d984604d9f88d4c6e04c0 cited By 20 E. Mortimer L.A. Kirstein F.M. Stuart M.R. Strecker article Walker2016691 The MH-2B borehole, a part of Project HOTSPOT, was drilled to a depth of 1821 m in late Cenozoic basalts, hyaloclastites and interbedded lake sediments, on the Mountain Home Air Force Base in southern Idaho, USA. Drillers encountered hot water (145°C) under artesian pressure at 1745 m in a narrow zone of highly fractured rock associated with a major sub-surface fault. X-ray diffraction (XRD) analysis identified corrensite (with and without smectite) between 1700 and 1800 m, but only smectite above 1700 m and below 1800 m. This corrensite horizon contains a relatively narrow zone of fracturing and hot artesian water near its centre but for the most part occurs in relatively massive basalt flows. No evidence was found for randomly interstratified chlorite-smectite. © 2016 by Walter de Gruyter Berlin/Boston. 2016 English 00098558 10.1180/claymin.2016.051.4.10 Clay Minerals 51 Mineralogical Society 691-696 Department of Earth Science and Geography, Vassar College, Poughkeepsie, NY, United States 4 X ray diffraction analysis, Air Force Base; Artesian pressure; Corrensite; Hyaloclastites; Lake sediments; Project hotspot; Smectites; Snake river plains, Basalt, artesian well; basalt; borehole breakout; Cenozoic; corrensite; hyaloclastite; hydrothermal alteration; lacustrine deposit; smectite, Idaho; Snake River Plain; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-85008192160&doi=10.1180%2fclaymin.2016.051.4.10&partnerID=40&md5=0e56fac4dc6d518043f4168b0c491dc1 cited By 2 J. Walker J. Wheeler article Hrubcová2016881 The waveforms of microearthquakes are of high frequency and complicated. They contain many phases secondarily generated at crustal interfaces and at small-scale inhomogeneities. They are highly sensitive to focal mechanisms and thus very different for each station of local networks. However, with a large number of microearthquakes, the scattered waves present in the waveforms can serve for identifying the prominent crustal discontinuities and for determining their depth. In this paper, we develop a new approach for extracting information on crustal structure from such waveforms and apply it for determining depth and lateral variations of crustal discontinuities. We show that strong dependence of microseismic waveforms on radiation pattern requires good station coverage and knowledge of focal mechanisms of the microearthquakes. Analysis of real observations is supported by waveform modeling and by analysis of radiation patterns of scattered waves. The robustness of the inversion for depth of crustal interfaces is achieved by stacking of a large number of waveforms and by applying a grid search algorithm. The method is demonstrated on two microseismic data sets of different origin: microseismicity induced during the Continental Super-Deep Drilling Project (KTB) 2000 fluid injection experiment and natural seismicity in the West Bohemia swarm region. High-frequency conversions at the KTB site indicate a prominent interface at depths of 2.3-4.1 km consistent with previous interpretations. Geologically, it may represent the contact of granitoids with much faster metabasites underneath. Seismicity in West Bohemia indicates a strong-contrast interface at depths of 3.5-6.0 km. This interface is in agreement with previous profiling and might be related to trapping of fluid emanations ascending from the mantle. ©2016. American Geophysical Union. All Rights Reserved. Article 2016 English 21699313 10.1002/2015JB012548 Journal of Geophysical Research: Solid Earth 121 Blackwell Publishing Ltd 881 – 902 2 Bohemian Massif; crustal structure; discontinuity; earthquake swarm; focal mechanism; microearthquake; seismic wave; waveform analysis https://www.scopus.com/inward/record.uri?eid=2-s2.0-84959420235&doi=10.1002%2f2015JB012548&partnerID=40&md5=391354c786c8354e37f6d0bebf5c3f43 Cited by: 11; All Open Access, Green Open Access, Hybrid Gold Open Access Pavla Hrubcová Václav Vavryčuk Alena Boušková Marco Bohnhoff article Bohnhoff2016132 The North Anatolian Fault Zone (NAFZ) in NW Turkey as one of the most active and best studied strike-slip faults provides a unique opportunity to study earthquake related relaxation processes through analyzing co- and postseismic deformation. We study the spatial and temporal distributions of seismicity related to the two consecutive 1999 M > 7 Izmit and Düzce earthquakes. A high-resolution aftershock catalogue including ~ 10,000 hypocenters extending along the combined rupture zone and extending from prior to the Izmit event to after the Düzce event is studied. Spatial and temporal distributions of events allow to identify distinct seismically active and inactive fault patches. Their location is related to the co- and postseismic deformation within and below the seismogenic layer, respectively. Four seismically inactive patches extending 30–50 km along the rupture zone and down to 10 km depth are identified with a systematic spatial shift between them introduced by the Düzce mainshock. The cumulative distribution of sub-areas hosting coseismic slip, aftershock clusters and postseismic creep shows that the entire upper (seismogenic) and lower (ductile) portions of the crust along the combined Izmit and Düzce rupture zone are activated between rupture initiation and a two-year postseismic period. This observation was only achieved due to the subsequent occurrence of two adjacent M > 7 strike-slip earthquakes in combination with a distinct local seismic and geodetic monitoring. Our findings suggest that a coseismically introduced lateral and vertical slip deficit is systematically compensated postseismically in both the brittle and ductile portions of the crust. © 2016 Elsevier B.V. 2016 English 00401951 10.1016/j.tecto.2016.07.029 Tectonophysics 686 Elsevier B.V. 132-145 Helmholtz Centre Potsdam GFZ German Research Centre for Geosciences, Section 4.2: Geomechanics and Rheology, Telegrafenberg, Potsdam, Germany; Free University Berlin, Department of Earth Sciences, Malteser Strasse 74-100, Berlin, 12249, Germany Creep; Strike-slip faults, Earthquake dynamics; NW Turkey; Postseismic creeps; Seismic cycle; Seismicity; Seismicity and tectonics; Seismotectonics; Spatial analysis, Earthquakes, coseismic process; creep; earthquake rupture; Kocaeli earthquake 1999; postseismic process; seismicity; seismotectonics; slip rate; spatial analysis; spatial distribution; spatial variation; temporal distribution; temporal variation, Duzce [Turkey]; Izmit; Kocaeli [Turkey]; Turkey https://www.scopus.com/inward/record.uri?eid=2-s2.0-84983027911&doi=10.1016%2fj.tecto.2016.07.029&partnerID=40&md5=e6cc3cd34b48f65f1811a02c0c94fd72 cited By 15 M. Bohnhoff M. Ickrath G. Dresen article Raub2016912 Using the first dataset available from the downhole Geophysical Observatory of the North Anatolian Fault, we investigated near-surface seismic-wave propagation on the Tuzla Peninsula, Istanbul, Turkey. We selected a dataset of 26 seismograms recorded at Tuzla at sensor depths of 0, 71, 144, 215, and 288 m. To determine near-surface velocities and attenuation structures, the waveforms from all sensors were pairwise deconvolved and stacked. This produced low-noise empirical Green’s functions for each borehole depth interval. From the Green’s functions, we identified reflections from the free surface and a low-velocity layer between ∼90 and ∼140 m depth. The presence of a low-velocity zone was also confirmed by a sonic log run in the borehole. This structure, plus high near-surface P- and S-wave velocities of ∼3600–4100 and ∼1800 m=s, lead to complex interference effects between upgoing and downgoing waves. As a result, the determination of quality factors (Q) with standard spectral ratio techniques was not possible. Instead, we forward modeled the Green’s functions in the time domain to determine effective Q values and to refine our velocity estimates. The effective QPvalues for the depth intervals of 0–71, 0–144, 0–215, and 0–288 m were found to be 19, 35, 39, and 42, respectively. For the S waves, we obtained an effective QS of 20 in the depth interval of 0–288 m. Considering the assumptions made in our modeling approach, it is evident that these effective quality factors are biased by impedance contrasts between our observation points. Our results show that, even after correcting for a free-surface factor of 2, the motion at the surface was found to be 1.7 times greater than that at 71 m depth. Our efforts also illustrate some of the difficulties of dealing with site effects in a strongly heterogeneous subsurface. © 2016, Seismological Society of America. All rights reserved. Article 2016 English 00371106 10.1785/0120150216 Bulletin of the Seismological Society of America 106 Seismological Society of America 912 – 927 3 Istanbul [Turkey]; Turkey; Tuzla [Istanbul]; Seismic waves; Seismology; Shear waves; Time domain analysis; Wave propagation; Well logging; Impedance contrast; Interference effects; Istanbul , Turkey; Low velocity layers; Low velocity zones; North Anatolian Fault; Observation point; P- and S-wave velocities; Green function; North Anatolian Fault; P-wave; S-wave; seismic wave; seismogram; shallow water; wave propagation; wave velocity; Velocity https://www.scopus.com/inward/record.uri?eid=2-s2.0-85011960981&doi=10.1785%2f0120150216&partnerID=40&md5=993696c90cd17045892ceabb07420b66 Cited by: 9; All Open Access, Green Open Access Christina Raub Marco Bohnhoff Bojana Petrovic Stefano Parolai Kenan Yanik Recai Feyiz Kartal Tuğbay Kiliç article juhlin_seismic_2016 2016 may en 1869-9529 10.5194/se-7-769-2016 Solid Earth 7 769--787 3 http://www.solid-earth.net/7/769/2016/ Christopher Juhlin Peter Hedin David G. Gee Henning Lorenz Thomas Kalscheuer Ping Yan article wenning_seismic_2016 Recent drilling of the first Collisional Orogeny in the Scandinavian Caledonides scientific borehole (COSC-1) near Åre, Sweden permitted a laboratory investigation of seismic anisotropy on high metamorphic grade and highly deformed core samples. The 2.5km deep borehole crosscuts the amphibolite-grade Lower Seve Nappe and intersects a high-strain shear zone in the lowermost 800m. Measurements of ultrasonic compressional (Vp) and shear (Vs) velocities are conducted at room temperature and pressures ranging from room conditions up to 260MPa on six core sections that represent the most abundant lithologies in the borehole. The core sections consist of two amphibolites, a calc-silicate gneiss, a felsic gneiss, an amphibole-rich gneiss, and a garnet-bearing micaschist from the shear zone. Three mutually perpendicular samples were taken to characterize the anisotropy induced by the clear foliation and lineation. The intrinsic (crack-free velocities) Vp0 and Vs0 in the direction perpendicular to foliation ranges from 5.51 to 6.67km/s and 3.31 to 4.13km/s, respectively. In the direction parallel to foliation the Vp0 and Vs0 ranges from 6.31 to 7.25km/s and 3.53 to 4.35km/s, respectively. Vp anisotropy ranges from 3% in the calc-silicate gneiss to 19% in the micaschist. In the upper crustal seismic reflection survey around the COSC-1 borehole, reflection coefficient analysis suggests that reflectors occur due to impedance contrast between commonly occurring amphibolites and gneisses in the upper 1800m and the micaschists below. When extrapolated to mid-crustal levels the analysis indicates that both rock types can produce reflection coefficients between adjacent lithologies in excess of 0.1. Similarities in lithologies, shear zone thickness, and reflectivity pattern in the Central Scandinavian Caledonides compared to other orogens (e.g., the Himalaya) demonstrate the importance of these measurements as a proxy for in-situ strongly anisotropic shear zones in the middle crust. 2016 dec 0040-1951 10.1016/j.tecto.2016.07.002 Tectonophysics 692 {SI}:{Crustal} seismology 14--28 Shear zone, Seismic anisotropy seismic velocity, Caledonian orogen, Middle crust reflectivity, Deep scientific drilling http://www.sciencedirect.com/science/article/pii/S0040195116302529 Quinn C. Wenning Bjarne S. G. Almqvist Peter Hedin Alba Zappone article Bohnhoff2016147 Constraining the maximum likely magnitude of future earthquakes on continental transform faults has fundamental consequences for the expected seismic hazard. Since the recurrence time for those earthquakes is typically longer than a century, such estimates rely primarily on well-documented historical earthquake catalogs, when available. Here we discuss the maximum observed earthquake magnitudes along different sections of the North Anatolian Fault Zone (NAFZ) in relation to the age of the fault activity, cumulative offset, slip rate and maximum length of coherent fault segments. The findings are based on a newly compiled catalog of historical earthquakes in the region, using the extensive literary sources that exist owing to the long civilization record. We find that the largest M7.8-8.0 earthquakes are exclusively observed along the older eastern part of the NAFZ that also has longer coherent fault segments. In contrast, the maximum observed events on the younger western part where the fault branches into two or more strands are smaller. No first-order relations between maximum magnitudes and fault offset or slip rates are found. The results suggest that the maximum expected earthquake magnitude in the densely populated Marmara-Istanbul region would probably not exceed M7.5. The findings are consistent with available knowledge for the San Andreas Fault and Dead Sea Transform, and can help in estimating hazard potential associated with different sections of large transform faults. © 2016 The Authors. 2016 English 00401951 10.1016/j.tecto.2016.02.028 Tectonophysics 674 Elsevier B.V. 147-165 Helmholtz-Centre Potsdam GFZ German Centre for Geosciences, Telegrafenberg, Potsdam, 14473, Germany; Department of Earth Sciences, Free University Berlin, Malteser Strasse 74-100, Berlin, 12249, Germany; Department of Earth Sciences, University of Southern California, Los Angeles, CA 90089-0740, United States Earthquakes; Hazards; Seismology; Strike-slip faults; Structural geology; Transform faults, Continental transform; Earthquake magnitudes; Fault zone; Historical seismicity; North Anatolian Fault Zone, Fault slips, continental margin; earthquake catalogue; earthquake magnitude; fault zone; hazard assessment; North Anatolian Fault; San Andreas Fault; seismic source; seismicity; seismology; transform fault, Dead Sea; Istanbul [Turkey]; Marmara [Turkey]; Turkey https://www.scopus.com/inward/record.uri?eid=2-s2.0-84959922037&doi=10.1016%2fj.tecto.2016.02.028&partnerID=40&md5=b549247ada651bd06909b427f8ba32b9 cited By 67 M. Bohnhoff P. Martínez-Garzón F. Bulut E. Stierle Y. Ben-Zion article Kominz20161437 Onshore drilling by Ocean Drilling Program (ODP) Legs 150X and 174AX and offshore drilling by Integrated Ocean Drilling Program (IODP) Expedition 313 provides continuous cores and logs of seismically imaged Lower to Middle Miocene sequences. We input ages and paleodepths of these sequences into one-dimensional backstripping equations, progressively accounting for the effects of compaction, Airy loading, and thermal subsidence. The resulting difference between observed subsidence and theoretical thermal subsidence provide relative sea-level curves that reflect both global average sea level and non-thermal subsidence. In contrast with expectations, backstripping suggests that the relative sea-level maxima in proximal onshore sites were lower than correlative maxima on the shelf. This requires that the onshore New Jersey coastal plain has subsided relative to the shelf, which is consistent with models of relative epeirogeny due to subduction of the Farallon plate. These models predict subsidence of the coastal plain relative to the shelf. Although onshore and offshore sea-level estimates are offset by epeirogeny, the amplitude of million-year-scale Early to Middle Miocene sea-level changes seen at the New Jersey margin is generally 5-20 m and occasionally as great as 50 m. These events are interpreted to represent eustatic variations, because they occur on a shorter time frame than epeirogenic influences. Correction for epeirogenic effects largely reconciles differences between onshore and offshore relative sea-level estimates and suggests that backstripping provides a testable eustatic model for the Early to Middle Miocene. 2016 English 1553040X 10.1130/GES01241.1 Geosphere 12 Geological Society of America 1437-1456 Department of Geosciences, Western Michigan University, 1186 Rood Hall, 1903 West Michigan Avenue, Kalamazoo, MI 49008, United States; Department of Earth and Planetary Sciences, Institute of Earth, Oceans, and Atmospheric Sciences, Rutgers, The State University of New Jersey, 610 Taylor Road, Piscataway, NJ 08854-8066, United States; Department of Earth and Planetary Sciences, Rutgers, The State University of New Jersey, 610 Taylor Road, Piscataway, NJ 08854-8066, United States; Department of Earth and Environmental Sciences, Rensselaer Polytechnic Institute, 110 8th Street, Troy, NY 12180, United States 5 Offshore drilling; Submarine geology; Subsidence; Tectonics, Continental shelves; Integrated ocean drilling programs; Middle Miocene; Ocean drilling programs; Offshore sea level; Onshore drilling; Relative sea level; Sealevel change, Sea level, coastal plain; continental shelf; eustacy; Miocene; Ocean Drilling Program; paleoceanography, New Jersey; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-84993967985&doi=10.1130%2fGES01241.1&partnerID=40&md5=429a4c7ca9a661f7d42fba0c2c016699 cited By 26 M.A. Kominz K.G. Miller J.V. Browning M.E. Katz G.S. Mountain article Estrella2016327 The NW Bohemia/Vogtland region is characterized by currently ongoing geodynamic processes within the intracontinental lithospheric mantle. Among others, this activity results in the occurrence of mid-crustal earthquake swarms and CO2 degassing zones called mofettes. These two natural phenomena are related to each other since it is considered that fluid flow and fluid-induced effective stress can trigger earthquake swarms. At the Earth's surface, they appear spatially separated, but their connection could be explained by the existence of pathways within the crust that allow efficient and permanent fluid transport. However, neither the structure nor the position of such pathways has been imaged yet. With this background, we used a matched field processing analysis within the NW Bohemia/Vogtland region to locate mofettes and investigate their characteristics. Considering the CO2 degassing process as a high-frequency noise source, we chose two different test sites: the Dolní Částkov Borehole, which is an artificial mofette that we used to validate the method, and the South Hartoušov mofette field, a natural CO2 degassing area. On both sites, we measured seismic noise in a continuous mode for several hours (7 hours to 9 hours), with a sampling frequency of 250 samples/second, in multiple campaigns using an array of about 60 × 60 m2 with approximately 30 randomly distributed stations. For the matched field processing computation, the phase velocity c(□) of the study area is required, which we obtained from active seismic experiments with vertical hammer-blow as the source. The phase velocity varies between 200 m/s and 420 m/s for Dolní Částkov and between 100 m/s and 280 m/s for South Hartoušov, both in a frequency range of 7 Hz-60 Hz. With the matched field processing analysis at the artificial mofette in Dolní Částkov, we could relocate the noise source successfully. In the South Hartoušov mofette field, we detected one dominant vertically extended noise source, probably a fluid pathway, as well as a small matched field processing maxima at the surface that can be related to a dry mofette. © 2016 European Association of Geoscientists & Engineers. Article 2016 English 15694445 10.3997/1873-0604.2016024 Near Surface Geophysics 14 EAGE Publishing BV 327 – 335 4 Bohemia; Czech Republic; Germany; Vogtland; array; borehole; degassing; earthquake event; earthquake swarm; effective stress; fluid flow; phase velocity; seismic noise https://www.scopus.com/inward/record.uri?eid=2-s2.0-85020474020&doi=10.3997%2f1873-0604.2016024&partnerID=40&md5=db6a8a6d0da7c9ce55df87b9778602c7 Cited by: 9 Hortencia Flores Estrella Josefine Umlauft Andreas Schmidt Michael Korn article Hauffe20162901 The Balkan Lake Ohrid is the oldest and most diverse freshwater lacustrine system in Europe. However, it remains unclear whether species community composition, as well as the diversification of its endemic taxa, is mainly driven by dispersal limitation, environmental filtering, or species interaction. This calls for a holistic perspective involving both evolutionary processes and ecological dynamics, as provided by the unifying framework of the "metacommunity speciation model". The current study used the species-rich model taxon Gastropoda to assess how extant communities in Lake Ohrid are structured by performing process-based metacommunity analyses. Specifically, the study aimed (1) to identifying the relative importance of the three community assembly processes and (2) to test whether the importance of these individual processes changes gradually with lake depth or discontinuously with eco-zone shifts. Based on automated eco-zone detection and processspecific simulation steps, we demonstrated that dispersal limitation had the strongest influence on gastropod community composition. However, it was not the exclusive assembly process, but acted together with the other two processes - environmental filtering and species interaction. The relative importance of the community assembly processes varied both with lake depth and eco-zones, though the processes were better predicted by the latter. This suggests that environmental characteristics have a pronounced effect on shaping gastropod communities via assembly processes. Moreover, the study corroborated the high importance of dispersal limitation for both maintaining species richness in Lake Ohrid (through its impact on community composition) and generating endemic biodiversity (via its influence on diversification processes). However, according to the metacommunity speciation model, the inferred importance of environmental filtering and biotic interaction also suggests a small but significant influence of ecological speciation. These findings contribute to the main goal of the Scientific Collaboration on Past Speciation Conditions in Lake Ohrid (SCOPSCO) deep drilling initiative - inferring the drivers of biotic evolution - and might provide an integrative perspective on biological and limnological dynamics in ancient Lake Ohrid. © Author(s) 2016. Review 2016 English 17264170 10.5194/bg-13-2901-2016 Biogeosciences 13 Copernicus GmbH 2901 – 2911 Department of Animal Ecology and Systematics, Justus Liebig University, Giessen, Germany 10 Balkan; Lake Ohrid; Turkmenistan; Gastropoda; assembly rule; biodiversity; biozonation; community dynamics; dispersal; ecozone; evolutionary biology; gastropod; holistic approach; lacustrine environment; relative abundance; speciation (biology); species richness https://www.scopus.com/inward/record.uri?eid=2-s2.0-84975467532&doi=10.5194%2fbg-13-2901-2016&partnerID=40&md5=95337217a2e60e86231c96800630645e Cited by: 15; All Open Access, Gold Open Access, Green Open Access Torsten Hauffe Christian Albrecht Thomas Wilke article Jovanovska2016031 A new diatom genus, Cribrionella gen. nov., is described from Quaternary sediments of Lake Ohrid. Cribrionella comprises distinct morphological features, such as: i) presence of submarginal alveoli followed by regularly or irregularly arranged areolae, ii) cribra on external areolar openings, iii) absence of silicate layers on internal areolar openings, but presence of thick and inwardly raised circumferential silica trabeculae, iv) rimoportulae positioned on costae, and v) absence of central fultoportulae. Detailed light and scanning electron microscope analyses were undertaken and used for comparison to morphologically related genera. The typus generis Cribrionella ohridana is compared to species from its morphologically closest genus Cyclotella sensu stricto (e.g., C. atomus, C. delicatula, C. bifacialis). Cribrionella ohridana has not been reported from the extant diatom flora of Lake Ohrid, nor in the nearby Lake Prespa. The discovery of a new genus in Lake Ohrid confirms again the importance of the lake, not only in light of species richness and endemicity, but also in evolutionary history of the family Stephanodiscaceae. © 2016 Magnolia Press. Article 2016 English 11793155 10.11646/phytotaxa.252.1.3 Phytotaxa 252 Magnolia Press 031 – 042 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84960194768&doi=10.11646%2fphytotaxa.252.1.3&partnerID=40&md5=5984acb01c850b71122733c9d3732ff2 Cited by: 3 Elena Jovanovska Aleksandra Cvetkoska Slavica Tofilovska Nadja Ognjanova-Rumenova Zlatko Levkov article vanBree2016132 We studied the high-resolution and well-dated 25,000 year sedimentary record of Lake Challa, a deep tropical crater lake in equatorial East Africa, to explore new proxies for paleoenvironmental and paleohydrological change. Sedimentary biomarker analysis revealed the presence of des-A-triterpenoids with oleanane, ursane and lupane carbon skeletons, microbial degradation products of angiosperm plant triterpenoids. Their increased influx from 16,000 years ago corresponds with previously documented changes in the terrestrial vegetation of the Lake Challa basin during postglacial warming, in particular the relative increase in C3/C4 plant ratio inferred from the stable carbon isotopic signature (δ13C) of sedimentary n-alkanes derived from plant leaf waxes. In contrast to this n-alkane δ13C signature, the δ13C of des-A-lupane maintains a constant value of −27.4 ± 1.1‰ across the glacial–interglacial transition. Since des-A-lupane is derived from C3 plants, its δ13C signature is here proposed to represent a novel and independent proxy for the time-variable carbon isotopic composition of local terrestrial C3 plants, which can improve estimates of the C3/C4 plant ratio based on two-end member mixing models of n-alkane δ13C values. © 2016 Elsevier Ltd 2016 English 01466380 10.1016/j.orggeochem.2016.09.003 Organic Geochemistry 101 Elsevier Ltd 132-139 NIOZ Royal Netherlands Institute for Sea Research, Department of Marine Microbiology and Biogeochemistry, Utrecht University, PO Box 59, AB Den Burg, 1790, Netherlands; Utrecht University, Faculty of Geosciences, Department of Earth Sciences, PO Box 80.115, TC Utrecht, 3508, Netherlands; Department of Botany and Microbiology, Addiriyah Chair for Environmental Studies, College of Science, King Saud University, P.O. Box 2455, Riyadh, 11451, Saudi Arabia; Ghent University, Limnology Unit, K.L. Ledeganckstraat 35, Gent, B-9000, Belgium Biodegradation; Degradation; Isotopes; Lakes; Sedimentology; Vegetation, Carbon isotopic composition; Des-A-lupane; East Africa; Interglacial transitions; Lacustrine sediments; Microbial degradation; Terrestrial vegetation; Triterpenoids, Paraffins, alkane; angiosperm; C3 plant; C4 plant; carbon isotope; isotopic ratio; lacustrine deposit; leaf; microbial activity; paleoenvironment; paleohydrology; Postglacial; reconstruction; stable isotope; terpene; warming; wax, Kilimanjaro [Tanzania]; Lake Challa; Tanzania, Magnoliophyta https://www.scopus.com/inward/record.uri?eid=2-s2.0-84988939092&doi=10.1016%2fj.orggeochem.2016.09.003&partnerID=40&md5=b53a6f65480aba981180fb2bec9c4f50 cited By 11 L.G.J. Bree W.I.C. Rijpstra N.A. Al-Dhabi D. Verschuren J.S. Sinninghe Damsté J.W. Leeuw techreport dobson_deep_2016 2016 Lawrence Berkeley National Laboratory (LBNL)

Berkeley, CA (United States)

124 http://www.osti.gov/scitech/biblio/1306290 Patrick Dobson Chin-Fu Tsang Timothy Kneafsey Sharon Borglin Yvette Piceno Gary Andersen Seiji Nakagawa Kurt Nihei Jonny Rutqvist Christine Doughty others article Williams201676 X-ray computed tomography (CT) scans of drill-core, recovered from the first phase of the Deep Fault Drilling Project (DFDP-1) through New Zealand's Alpine Fault, provide an excellent opportunity to study the damage zone of a plate-bounding continental scale fault, late in its interseismic cycle. Documentation of the intermediate-macro scale damage zone structures observed in the CT images show that there is no increase in the density of these structures towards the fault's principal slip zones (PSZs), at least within the interval sampled, which is 30 m above and below the PSZs. This is in agreement with independent analysis using borehole televiewer data. Instead, we conclude the density of damage zone structures to correspond to lithology. We find that 72% of fractures are fully healed, by a combination of clays, calcite and quartz, with an additional 24% partially healed. This fracture healing is consistent with the Alpine Fault's late interseismic state, and the fact that the interval of damage zone sampled coincides with an alteration zone, an interval of extensive fluid-rock interaction. These fractures do not impose a reduction of P-wave velocity, as measured by wireline methods. Outside the alteration zone there is indirect evidence of less extensive fracture healing. © 2016 Elsevier Ltd 2016 English 01918141 10.1016/j.jsg.2016.07.006 Journal of Structural Geology 90 Elsevier Ltd 76-94 Department of Geology, University of Otago, PO Box 56, Dunedin, 9054, New Zealand; School of Geography, Environment, and Earth Sciences, Victoria University of Wellington, PO Box 600, Wellington, 6012, New Zealand; GNS Science, PO Box 30-368, Lower Hutt, 5040, New Zealand; Department of Mathematics and Statistics, University of Otago, PO Box 56, Dunedin, 9054, New Zealand Fracture; Lithology; Seismic waves; Wave propagation, Alpine Faults; Continental scale; Damage zones; DFDP; Fluid-rock interaction; Fracture density; Independent analysis; X-ray computed tomography, Computerized tomography, earthquake damage; fault zone; fracture; lithology; P-wave; plate boundary; slip; wave velocity, Alpine Fault Zone; New Zealand; South Island https://www.scopus.com/inward/record.uri?eid=2-s2.0-84979787946&doi=10.1016%2fj.jsg.2016.07.006&partnerID=40&md5=df6dd4d3773e735488ed8b06731fdff1 cited By 27 J.N. Williams V.G. Toy C. Massiot D.D. McNamara T. Wang article Sánchez-Pastor2016271 Article 2016 10.1016/j.gca.2015.12.006 Geochimica et Cosmochimica Acta 175 271 – 281 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84953225342&doi=10.1016%2fj.gca.2015.12.006&partnerID=40&md5=b8d8b330080fb6d6341f8e6ccb00393f Cited by: 38; All Open Access, Green Open Access N. Sánchez-Pastor Markus Oehlerich José Manuel Astilleros Melanie Kaliwoda Christoph C. Mayr Lurdes Fernández-Díaz Wolfgang W. Schmahl article Luetkemeyer2016174 The San Andreas Fault Observatory at Depth (SAFOD), near Parkfield, California, is a borehole drilled through two active deforming zones of the San Andreas fault, the Southwest Deforming Zone (SDZ) and the Central Deforming Zone (CDZ). These zones accommodate displacement by seismic slip and aseismic creep. Elevated fluid pressures and fluid–rock interactions have been proposed to explain the low apparent strength and aseismic creep observed, but the origin of the fluids and existence of high fluid pressures remains uncertain. We use clumped-isotope thermometry and δ18O–δ13C compositions of calcite in veins to constrain the origin of paleofluids and compare these results to the isotopic composition of modern-day pore fluids from the SAFOD borehole and nearby areas. We observe that: (1) calcite vein temperatures vary from 81 to 134 °C, which overlaps the current ambient borehole temperatures of 110–115 °C at sampled depths; (2) vein calcite is not in carbon isotope equilibrium with modern-day pore fluids; (3) the δ18O values of paleofluids close to the SDZ and CDZ, calculated from vein δ18O and temperature data, are not in equilibrium with local modern-day pore waters but approach equilibrium with modern pore waters far from these zones; and (4) syntectonic vein calcite is only in C- and O-isotopic equilibrium with their host rocks within the SDZ and CDZ. Spatial patterns of δ18O and δ13C show little evidence for across-fault fluid-flow. Clumped isotope temperatures are consistent with locally-derived fluid sources, but not with continuous or episodic replenishment of fluids from shallow sedimentary brines or deep fluid sources. Our findings are compatible with flow of meteoric fluids from the southwestern damage zone into the SDZ and CDZ, which would have favored the formation of weak phyllosilicates and contributed to the present day weakness of the two actively deforming zones. © 2016 Elsevier B.V. 2016 English 00401951 10.1016/j.tecto.2016.05.024 Tectonophysics 690 Elsevier B.V. 174-189 Department of Earth and Atmospheric Sciences, Saint Louis University, 205 O'Neil Hall, 3642 Lindell Blvd, Saint Louis, MO 63108, United States; Department of Earth and Space Sciences, University of Washington, Seattle, WA 98195, United States; Department of Geology and Geophysics, Texas A & M University, College Station, TX 77843, United States; Department of Geology, Utah State University, Logan, UT 84322-4505, United States Calcite; Carbon; Creep; Deformation; Faulting; Fluids; Isotopes; Observatories; Silicates; Strike-slip faults; Thermometers; Water, Borehole temperature; Calcite veins; Clumped isotopes; Fluid-rock interaction; Isotopic composition; SAFOD; San Andreas fault; Syn-tectonic veins, Flow of fluids, borehole geophysics; calcite; carbonate rock; fault zone; fracture flow; hydrogeology; isotopic composition; meteoric water; San Andreas Fault; vein (geology); water-rock interaction, California; Parkfield; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-84971597832&doi=10.1016%2fj.tecto.2016.05.024&partnerID=40&md5=e110e67c29fa1be2bf4ae1ad21fa672a cited By 13 P.B. Luetkemeyer D.L. Kirschner K.W. Huntington J.S. Chester F.M. Chester J.P. Evans article Huang2016182 Geochemical analyses of stratigraphic sequences of lava flows are necessary to understand how a volcano works. Typically one sample from each lava flow is collected and studied with the assumption that this sample is representative of the flow composition. This assumption may not be valid. The thickness of flows ranges from &lt;1 to &gt;100 m. Geochemical heterogeneity in thin flows may be created by interaction with the surficial environment whereas magmatic processes occurring during emplacement may create geochemical heterogeneities in thick flows. The Hawaii Scientific Drilling Project (HSDP) cored ∼3.3 km of basalt erupted at Mauna Kea Volcano. In order to determine geochemical heterogeneities in a flow, multiple samples from four thick (9.3–98.4 m) HSDP flow units were analyzed for major and trace elements. We found that major element abundances in three submarine flow units are controlled by the varying proportion of olivine, the primary phenocryst phase in these samples. Post-magmatic alteration of a subaerial flow led to loss of SiO2, CaO, Na2O, K2O and P2O5, and as a consequence, contents of immobile elements, such as Fe2O3 and Al2O3, increase. The mobility of SiO2 is important because Mauma Kea shield lavas divide into two groups that differ in SiO2 content. Post-magmatic mobility of SiO2 adds complexity to determining if these groups reflect differences in source or process. The most mobile elements during post-magmatic subaerial and submarine alteration are K and Rb, and Ba, Sr and U were also mobile, but their abundances are not highly correlated with K and Rb. The Ba/Th ratio has been used to document an important role for a plagioclase-rich source component for basalt from the Galapagos, Iceland and Hawaii. Although Ba/Th is anomalously high in Hawaiian basalt, variation in Ba abundance within a single flow shows that it is not a reliable indicator of a deep source component. In contrast, ratios involving elements that are typically immobile, such as La/Nb, La/Th, Nb/Th, Ce/Pb, Sr/Nd, La/Sm, Sm/Yb, Nb/Zr, Nb/Y and La/Yb, are uniform within the units, and they can be used to constrain petrogenetic processes. Nevertheless all elements are mobile under some conditions. For example, a surprising result is that relative to other samples, the uppermost sample collected from subaerial flow Unit 70, less than 1 m below the flow surface, is depleted in P, HREE and Y relative to all other samples from this flow unit. This result is complementary to the P, REE and Y enrichment found in subaerial lava flows from several Hawaiian shields, e.g., Kahoolawe and Koolau Volcanoes. These enrichments require mobilization of REE and followed by deposition a P-rich mineral. © 2016 Elsevier Ltd Article 2016 English 00167037 10.1016/j.gca.2016.01.015 Geochimica et Cosmochimica Acta 185 Elsevier Ltd 182-197 Department of Geoscience, University of Nevada, Las Vegas, United States; Department of Geosciences, University of Massachusetts Amherst, United States; Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, United States; School of Earth and Space Sciences, University of Science and Technology of China, China chemical composition; core analysis; element mobility; enrichment; igneous geochemistry; lava flow; sequence stratigraphy; shield volcano; trace element; volcanic rock, Hawaii [(ISL) Hawaiian Islands]; Hawaii [United States]; Hawaiian Islands; Mauna Kea https://www.scopus.com/inward/record.uri?eid=2-s2.0-84958576544&doi=10.1016%2fj.gca.2016.01.015&partnerID=40&md5=2b0512f6e7e083113ffe1015fcd726be cited By 6 S. Huang M.J. Vollinger F.A. Frey J.M. Rhodes Q. Zhang article Zhang20161351 Lake Ohrid (Macedonia and Albania) is a rare example of a deep, ancient Mediterranean lake and is a key site for palaeoclimate research in the northeastern Mediterranean region. This study conducts the analysis of diatoms as a proxy for Lateglacial and Holocene climate and environmental change in Lake Ohrid at a higher resolution than in previous studies. While Lake Ohrid has the potential to be sensitive to water temperature change, the data demonstrate a highly complex diatom response, probably comprising a direct response to temperature-induced lake productivity in some phases and an indirect response to temperaturerelated lake stratification or mixing and epilimnetic nutrient availability in others. The data also demonstrate the possible influence of physical limnological (e.g. the influence of wind stress on stratification or mixing) and chemical processes (e.g. the influence of catchment dynamics on nutrient input) in mediating the complex response of diatoms. During the Lateglacial (ca. 12 300-11 800 cal yr BP), the low-diversity dominance of hypolimnetic Cyclotella fottii indicates low lake productivity, linked to low water temperature. Although the subsequent slight increase in small, epilimnetic C. minuscula during the earliest Holocene (ca. 11 800-10 600 cal yr BP) suggests climate warming and enhanced stratification, diatom concentration remains as low as during the Lateglacial, suggesting that water temperature increase was muted across this major transition. The early Holocene (ca. 10 600-8200 cal yr BP) is characterised by a sustained increase in epilimnetic taxa, with mesotrophic C. ocellata indicating high water-temperature-induced productivity between ca. 10 600-10 200 cal yr BP and between ca. 9500-8200 cal yr BP and with C. minuscula in response to low nutrient availability in the epilimnion between ca. 10 200-9500 cal yr BP. During the middle Holocene (ca. 8200-2600 cal yr BP), when sedimentological and geochemical proxies provide evidence for maximum Holocene water temperature, anomalously low C. ocellata abundance is probably a response to epilimnetic nutrient limitation, almost mimicking the Lateglacial flora apart from the occurrence of mesotrophic Stephanodiscus transylvanicus in the hypolimnion. During the late Holocene (ca. 2600 cal yr BP-present), high abundance and fluctuating composition of epilimnetic taxa are probably a response more to enhanced anthropogenic nutrient input, particularly nitrogen enrichment, than to climate. Overall, the data indicate that previous assumptions concerning the linearity of diatom response in this deep, ancient lake are invalid, and multi-proxy analysis is essential to improve understanding of palaeolimnological dynamics in future research on the long, Quaternary sequence. © Author(s) 2016. 2016 English 17264170 10.5194/bg-13-1351-2016 Biogeosciences 13 Copernicus GmbH 1351-1365 Institute of Loess Plateau, Shanxi University, Taiyuan, China; Department of Geography, Environment and Earth Sciences, University of Hull, Hull, United Kingdom; Centre for Environmental Geochemistry, School of Geography, University of Nottingham, Nottingham, United Kingdom; NERC Isotope Geosciences Facilities, British Geological Survey, Nottingham, United Kingdom; Institute of Geology and Mineralogy, University of Cologne, Cologne, Germany; Institute of Biology, Faculty of Natural Sciences, Ss. Cyril and Methodius University, Skopje, North Macedonia 4 butterfly; diatom; environmental change; epilimnion; Holocene; late glacial; nutrient availability; oligotrophic environment; paleolimnology; perciform; proxy climate record; water temperature, Albania; Lake Ohrid; Macedonia [Southern Europe], Bacillariophyta; Cyclotella; Cyclotella ocellata; Stephanodiscus https://www.scopus.com/inward/record.uri?eid=2-s2.0-84960075843&doi=10.5194%2fbg-13-1351-2016&partnerID=40&md5=03b8d5777cab8051ec40609ea44af554 cited By 9 X.S. Zhang J.M. Reed J.H. Lacey A. Francke M.J. Leng Z. Levkov B. Wagner article Schwarz2016307 High resolution 40Ar-39Ar step heating dating of australites and indochinites, representing a large area of the Australasian strewn field, and more recently discovered tektite-like glasses from Central America (Belize) and Western Canada, were carried out. Precise plateau ages were obtained in all cases, yielding indistinguishable ages of 789 ± 9 ka for four australites, 783 ± 5 ka for four indochinites, 783 ± 17 ka for one Western Canadian and 769 ± 16 ka for one Belize impact glass. Concerning major elements and REEs, australites and the Western Canadian impact glass are indistinguishable. If the Western Canadian sample was transported by impact ejection and belongs to the Australasian strewn field, this implies extremely far ballistic transport of 9000 km distance, assuming a source crater in southern Asia. The distinct major element and REE composition of the Belize impact glass suggests formation in another separate impact event. We conclude that the Australasian/Western Canadian impact glasses formed 785 ± 7 ka ago in a single event and Belize impact glass in a separate event 769 ± 16 ka ago. The two impact events forming these two strewn fields occurred remarkably closely related in time, i.e., separated by &lt;30 ka. © 2016 Elsevier Ltd. 2016 English 00167037 10.1016/j.gca.2015.12.037 Geochimica et Cosmochimica Acta 178 Elsevier Ltd 307-319 Institut für Geowissenschaften, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 234-236, Heidelberg, 69120, Germany; Klaus-Tschira-Labor für Kosmochemie, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 234-236, Heidelberg, 69120, Germany; Museum für Naturkunde - Berlin, Leibniz-Institut für Evolutions- und Biodiversitätsforschung, Invalidenstrasse 43, Berlin, D-10115, Germany; 7560 Greenboro Drive, #4, West Melbourne, FL 32904, United States; Institut für Planetologie, Universität Münster, Wilhelm Klemm Straße 10, Münster, 48419, Germany; Department of Lithospheric Research, University of Vienna, Althanstrasse 14, Vienna, 1090, Austria; Natural History Museum, Burgring 7, Vienna, 1010, Austria argon-argon dating; impact structure; Quaternary; rare earth element; tektite, Belize [Central America]; Canada https://www.scopus.com/inward/record.uri?eid=2-s2.0-84958535124&doi=10.1016%2fj.gca.2015.12.037&partnerID=40&md5=d37adcb77e5db6b454f4b506ad783662 cited By 27 W.H. Schwarz M. Trieloff K. Bollinger N. Gantert V.A. Fernandes H.-P. Meyer H. Povenmire E.K. Jessberger M. Guglielmino C. Koeberl article Jackson2016946 The occurrence of coesite in suevites from the Chesapeake Bay impact structure is confirmed within a variety of textural domains in situ by Raman spectroscopy for the first time and in mechanically separated grains by X-ray diffraction. Microtextures of coesite identified in situ investigated under transmitted light and by scanning electron microscope reveal coesite as micrometer-sized grains (1-3 μm) within amorphous silica of impact-melt clasts and as submicrometer-sized grains and polycrystalline aggregates within shocked quartz grains. Coesite-bearing quartz grains are present both idiomorphically with original grain margins intact and as highly strained grains that underwent shock-produced plastic deformation. Coesite commonly occurs in plastically deformed quartz grains within domains that appear brown (toasted) in transmitted light and rarely within quartz of spheroidal texture. The coesite likely developed by a mechanism of solid-state transformation from precursor quartz. Raman spectroscopy also showed a series of unidentified peaks associated with shocked quartz grains that likely represent unidentified silica phases, possibly including a moganite-like phase that has not previously been associated with coesite. © 2016 The Meteoritical Society. 2016 English 10869379 10.1111/maps.12638 Meteoritics and Planetary Science 51 University of Arkansas 946-965 U.S. Geological Survey, Reston, VA 20192, United States; Sanya Institute of Deep-Sea Science and Engineering, Sanya, China 5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84961825632&doi=10.1111%2fmaps.12638&partnerID=40&md5=78ab203a4ca643a2524806d387bf4d66 cited By 7 J.C. Jackson Jr. Horton I.-M. Chou H.E. Belkin article Kim20161910 Finite-source inversions are performed using small earthquake waveforms as empirical Green's functions (eGf) to investigate the rupture process of repeating earthquakes along the San Andreas Fault in Parkfield, California. The eGf waveform inversion method is applied to a repeating Mw 2.1 Parkfield earthquake sequence using three-component velocity waveforms recorded by an array of borehole seismometers. The obtained models show a circular slip distribution with a ~20 m radius, a 3.0-4.2 cm average slip of the main asperity, and peak displacement of 10.6-13.5 cm. The static stress drop distribution shows that the main asperity has a peak stress drop of 69.5-94.7 MPa. The inversion results support an earlier finding by Dreger et al. (2007) that high-strength asperities exist in the rupture areas of the Mw 2.1 events at Parkfield. In addition, notable temporal peak slip and stress drop reduction was observed after the 2004 Parkfield event while the average value remains constant (~12 MPa) over time. These events may represent mechanically strong sections of the fault, surrounded by regions that are undergoing continuous deformation (creep), Given repeated loading of the strong asperities, it would be expected that these similar repeating earthquakes should also have very similar slip distributions since surrounding regions are deforming aseismically. There are small differences in the waveforms of these repeating earthquakes, and this could be because of rupture nucleation points not being in exactly the same location within the region of the fault that is capable of stick-slip behavior. Our result indicates that waveform slip inversion is needed to reveal spatial and temporal variations of the stress drop within the rupture area to improve understanding of fault healing and rupture mechanics. ©2016. American Geophysical Union. All Rights Reserved. 2016 English 21699313 10.1002/2015JB012562 Journal of Geophysical Research: Solid Earth 121 Blackwell Publishing Ltd 1910-1926 Department of Materials System Science, Yokohama City University, Yokohama, Japan; Berkeley Seismological Laboratory, University of California, Berkeley, CA, United States 3 earthquake magnitude; earthquake prediction; earthquake rupture; fault displacement; Green function; inverse problem; San Andreas Fault; seismograph; stick-slip; stress; wave velocity, California; Parkfield; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-84961588774&doi=10.1002%2f2015JB012562&partnerID=40&md5=eec7135f66a5aa54ce84b24bbeeedf3c cited By 29 A. Kim D.S. Dreger T. Taira R.M. Nadeau article Thomas2016157 Lake Qinghai, located on the northeastern Tibetan Plateau north of the modern maximum summer monsoon extent, is well situated to record northward advances of the summer monsoon. Existing paleoclimate records contain conflicting evidence for the timing of summer monsoon advance into this region: an early arrival pre-Younger Dryas or a late arrival at the beginning of the Holocene. A 30-kyr-long leaf wax hydrogen isotope (n-alkanoic acid, δ2Hwax) record from Lake Qinghai helps to address this discrepancy by elucidating changes in the three main moisture sources in this region: southerly (summer monsoon), northwesterly, and local precipitation. Lake Qinghai δ2Hwax indicates that the arid glacial period was dominated by northwesterly moisture. Extremely arid conditions prevailed from 15 to 14 ka, likely because westerly winds were weakening and the summer monsoon had not yet reached this region. This arid period ended by 13.6 ka when small amounts of summer monsoon precipitation reached Lake Qinghai. Summer monsoon moisture subsequently retreated off of the northeastern Tibetan Plateau during the Younger Dryas and re-advanced in the early Holocene. Summer monsoon precipitation decreased progressively throughout the Holocene in response to decreasing summer insolation, and the modern northwesterly- and local-dominated moisture regime was attained ca. 2.6 ka. Lake Qinghai δ2Hwax demonstrates that the summer monsoon extent was dynamic during the past 30 kyr, responding dramatically to insolation and North Atlantic circulation changes. Moreover, Lake Qinghai δ2Hwax demonstrates that local and northwesterly air masses are important moisture sources to the northeastern Tibetan Plateau, and should be considered when reconstructing past hydroclimate in this region. © 2015 Elsevier Ltd. 2016 English 02773791 10.1016/j.quascirev.2015.11.003 Quaternary Science Reviews 131 Elsevier Ltd 157-167 Department of Earth, Environmental, and Planetary Sciences, Brown University, Providence, RI 02912, United States; Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, 710061, China; Large Lakes Observatory, University of Minnesota, Duluth, MN 55812, United States; Cooperative Institute for Research in Environmental Sciences, University of Colorado and NOAA's National Centers for Environmental Information, Boulder, CO 80305, United States Incident solar radiation; Isotopes; Lakes; Moisture; Solar radiation, Holocenes; Hydrogen isotope; Monsoon; Tibetan Plateau; Westerlies; Younger Dryas, Atmospheric thermodynamics, Holocene; hydrogen isotope; moisture content; monsoon; paleoclimate; precipitation (climatology); Quaternary; wax; westerly, China; Qinghai; Qinghai Lake; Qinghai-Xizang Plateau https://www.scopus.com/inward/record.uri?eid=2-s2.0-84946781112&doi=10.1016%2fj.quascirev.2015.11.003&partnerID=40&md5=3bf44a291215dd1c5784393eda57d2d3 cited By 75 E.K. Thomas Y. Huang S.C. Clemens S.M. Colman C. Morrill P. Wegener J. Zhao article Shashidhar2016661 The Koyna region located near the west coast of India has been continuously having artificial water-reservoir-triggered earthquakes since the impoundment of Koyna Dam in 1962. To improve the accuracy of locations of these triggered earthquakes, a unique network of eight borehole seismometers surrounding the seismicity was designed. Five of these have been installed at depths varying from 1134 to 1522 m, well below the Deccan basalt cover. As it is difficult to install the borehole seismometers with desired orientation of the horizontal components, amplitudes of P waves were used to decipher the true orientations after installation. Analysis of data for the period March-June 2015 demonstrated that there is a remarkable increase in the number of earthquakes located with the help of borehole seismometers. Using the existing network of 21 broadband surface seismometers, 184 earthquakes of ML ≥ 0:5 were located; however, with the borehole seismometers, the number of the located events increased to 888 such events. The data also indicate an increase in seismic activity corresponding to the period of increase in the rate of emptying of the Koyna and Warna reservoirs. 2016 English 08950695 10.1785/0220150210 Seismological Research Letters 87 Seismological Society of America 661-667 Seismology Division, Council of Scientific and Industrial Research-National Geophysical Research Institute (CSIR-NGRI), Cyber Building Uppal Road, Hyderabad, Telangana, 500007, India 3 Geophysics; Reservoirs (water); Seismic waves; Seismographs; Seismology, Analysis of data; Artificial water; P waves; Seismic activity; Seismic networks; Triggered Earthquakes; West coast, Earthquakes, borehole geophysics; earthquake mechanism; P-wave; reservoir impoundment; reservoir-induced seismicity; seismicity; seismograph; trigger mechanism, India; Koyna Dam; Maharashtra https://www.scopus.com/inward/record.uri?eid=2-s2.0-84975873869&doi=10.1785%2f0220150210&partnerID=40&md5=492e398f1c94370ff669e5094d165bd9 cited By 20 D. Shashidhar H.V.S. Satyanarayana C.R. Mahato K. Mallika N.P. Rao H.K. Gupta article Najdahmadi2016931 We image velocity contrast (bimaterial) interfaces along the Karadere Fault of the North Anatolian Fault Zone, toward the eastern part of the 1999 Izmit Mw 7.4 rupture in NW Turkey, using waveforms recorded by a local seismic network. Applying an automatic procedure for identification and picking of fault zone head waves (FZHW) and direct P arrivals, and manually revising the picks through particle motion analysis, we identify two different groups of FZHW as well as fault zone reflected waves (FZRW). The first group of FZHW has a moveout with respect to the direct P arrivals with distance traveled along the fault, indicating a deep bimaterial interface down to the base of the seismogenic crust with an average velocity contrast of ~3.4%. The second group of FZHW has a constant time difference from the direct P arrivals and is associated with a shallow local interface bounding a low-velocity damage zone or basin structure that extends to a depth of 4-5 km. While the first group of FZHW exists on the slower crustal block, the second group of FZHW and the FZRW are present generally on both sides of the fault. These phases add to the richness and complexity of the early P waveforms observed at stations close to a large fault. The relatively low velocity contrast across the Karadere Fault compared to values to the west may have helped stopping the Izmit rupture. ©2016. American Geophysical Union. All Rights Reserved. 2016 English 21699313 10.1002/2015JB012601 Journal of Geophysical Research: Solid Earth 121 Blackwell Publishing Ltd 931-950 Geomechanics and Rheology, Helmholtz-Centre Potsdam, GFZ German Centre for Geosciences, Potsdam, Germany; Institute of Geological Sciences, Free University Berlin, Berlin, Germany; Department of Earth Sciences, University of Southern California, Los Angeles, CA, United States 2 fault zone; North Anatolian Fault; P-wave; wave reflection; waveform analysis, Turkey https://www.scopus.com/inward/record.uri?eid=2-s2.0-84959097882&doi=10.1002%2f2015JB012601&partnerID=40&md5=c7c04b4e755d5f6c76d05371737e9269 cited By 26 B. Najdahmadi M. Bohnhoff Y. Ben-Zion article Wang201698 Volcanism is a natural climate force that causes variations in temperatures. The Aptian Oceanic Anoxic Event 1a (OAE-1a) was preceded by a prominent negative C-isotope excursion attributed to major volcanism of the Ontong Java plateau (OJP), which presumably resulted in a pCO2 increase and a climatic change. However, the OJP alone may not adequately explain some important isotopic signatures such as the negative strontium-isotope excursion from 125 Ma to 113 Ma that is recorded in the corresponding marine deposits. We present an independent and hitherto undocumented case, the giant Aptian volcanism in the Songliao Basin and northeast Asia (SB-V) on the Cretaceous active continental margin between the Eurasian and the Pacific plates, which covered an area of ca. 2.3 × 106 km2, nearly matching the simultaneous case of the OJP. Intensive strong, explosive volcanic eruptions of the SB-V occurred at 121-109 Ma and introduced a large volume of fine-grained volcanic ash and degassing volatiles into the atmosphere. The Aptian isotopic ratios (87Sr/86Sr, 206Pb/204Pb, 207Pb/204Pb, and 208Pb/204Pb) of marine carbonates from the Mid-Pacific shift in values between their Barremian pre-excursion high values and the negative magmatic values of the SB-V. The transient global cooling at the onset of the OAE-1a coincided with the beginning of the violent acidic eruption of the SB-V (119.9-120.2 Ma). We therefore infer that the SB-V must have played a role in the Aptian global climatic changes and OAE-1a through the heavy fall of volcanic dust and the outgassing of aerosol and greenhouse gases. © 2015 Elsevier Ltd. 2016 English 01956671 10.1016/j.cretres.2015.09.021 Cretaceous Research 62 Academic Press 98-108 College of Earth Sciences, Jilin University, Changchun, 130061, China aerosol; anoxic conditions; Aptian; climate change; explosive volcanism; global change; greenhouse gas; isotopic analysis; volcanic ash; volcanic eruption, China; Northeast Asia; Ontong Java Plateau; Pacific Ocean; Songliao Basin https://www.scopus.com/inward/record.uri?eid=2-s2.0-84960812738&doi=10.1016%2fj.cretres.2015.09.021&partnerID=40&md5=246da79d3f65f1bf9f3070c5f44ff3e5 cited By 20 P. Wang C. Chen H. Liu article Jovanovska20161149 Ancient lakes, such as lakes Ohrid and Prespa on the Balkan Peninsula, have become model systems for studying the link between geological and biotic evolution. Recently, the scientific deep-drilling project Scientific Collaboration on Past Speciation Conditions in Lake Ohrid (SCOPSCO) was initiated to better understand the environmental, climatic, and limnological evolution of the lake. It revealed that Lake Ohrid experienced a number of environmental disturbances during its ca. 2.0 million year long history. These are comprised of disturbances that lasted over longer periods of time ("press events") such as glacial-interglacial cycles and Heinrich events, as well as sudden and short disturbances ("pulse events") like the deposition of landslides, earthquakes, and volcanic ash depositions. The latter includes one of the most severe volcanic episodes during the Late Pleistocene: the eruption of the Campanian Ignimbrite (known as Y-5 marine tephra layer) from the Campi Flegrei caldera, dated to 39.6 ± 0.1 thousand years ago. The event is recorded by the deposition of a ca. 15 cm thick tephra layer in sediment cores of lakes Ohrid (DEEP-5045-1) and Prespa (Co1204). Coincidently, this pulse event is superimposed by the Heinrich H4 event, 40.4-38.4 thousand years ago. In the current paper, diatoms were used as proxies to compare the responses of these lakes to the Y-5 (pulse) and the H4 (press) disturbances. Based on stratigraphically constrained incremental sum of squares cluster (CONISS) and unconstrained Partitioning Around Medoids (PAM) analyses, we found little evidence that diatom community compositions in either lake responded to the H4 event. However, the Y-5 influx caused clear and rapid diatom community changes. After the initial response, community compositions in Lake Ohrid and, to a lesser extent, in Lake Prespa slowly returned to their quasi pre-disturbance state. Moreover, there is no evidence for disturbance-related extinction events. The combined evidence from these findings suggests that lakes Ohrid and Prespa likely did not experience regime shifts. It is therefore concluded that both lakes show resilience to environmental disturbance. However, it seems that Lake Ohrid is more resilient than Lake Prespa, as the recovery of diatom communities is more pronounced and its estimated recovery time is only ca. 1100 years vs. ca. 4000 years in Lake Prespa. The reasons for the differential responses remain largely unknown, but differences in geology, lake age, limnology, and intrinsic parameters of the diatom proxies may play an important role. © Author(s) 2016. Article 2016 English 17264170 10.5194/bg-13-1149-2016 Biogeosciences 13 Copernicus GmbH 1149 – 1161 Department of Animal Ecology and Systematics, Justus Liebig University, Giessen, Germany; Palaeoecology, Department of Physical Geography, Faculty of Geosciences, Utrecht University, Utrecht, Netherlands; Institute of Biology, University Ss. Cyril and Methodius, Skopje, North Macedonia; Institute of Geology and Mineralogy, University of Cologne, Cologne, Germany; Dipartimento di Scienze della Terra e Geoambientali, Bari, Italy; IDPA-CNR, Milan, Italy 4 Balkans; Campania [Italy]; Campi Flegrei; Italy; Lake Mikri Prespa; Lake Ohrid; Napoli [Campania]; Bacillariophyta; Campanian; community composition; diatom; ecosystem resilience; environmental disturbance; glacial-interglacial cycle; Heinrich event; paleoclimate; Pleistocene; sediment core; speciation (biology) https://www.scopus.com/inward/record.uri?eid=2-s2.0-84959432923&doi=10.5194%2fbg-13-1149-2016&partnerID=40&md5=230af728b82e1c7689989850959fbd5c Cited by: 28; All Open Access, Gold Open Access, Green Open Access Elena Jovanovska Aleksandra Cvetkoska Torsten Hauffe Zlatko Levkov Bernd Wagner Roberto Sulpizio Alexander Francke Christian Albrecht Thomas Wilke incollection medvedev2016application Paleoproterozoic (2.0–2.2 Ga) stromatolites from drill cores of the ICDP Project FAR DEEP were studied by Raman spectroscopy and inductively coupled plasma mass spectrometry with laser ablation (LA-ICP MS) methods. Morphological features of the studied Paleoproterozoic stromatolites together with identification of synsedimentary carbonaceous matter by Raman spectroscopy are strong argument for biogenic origin of these carbonate buildups. Precision geochemical analysis of the stromatolite laminae composition links to sedimentary settings and environmental conditions of the microbialite formation. © 2016, Springer International Publishing Switzerland. 2016 English 21938571 10.1007/978-3-319-24987-2_26 Biogenic—Abiogenic Interactions in Natural and Anthropogenic Systems Lecture Notes in Earth System Sciences Springer 329--341 Institute of Geology, Karelian Research Centre, Russian Academy of Sciences, Petrozavodsk, Russian Federation 9783319249858 carbonate sediment; environmental conditions; geochemistry; inductively coupled plasma method; microbialite; Proterozoic; Raman spectroscopy; stromatolite, Baltic Shield; East European Craton https://www.scopus.com/inward/record.uri?eid=2-s2.0-85031924397&doi=10.1007%2f978-3-319-24987-2_26&partnerID=40&md5=61a51529fa2738c9bec6b15e8d33fbc9 cited By 1 Pavel V Medvedev Svetlana Y Chazhengina Sergey A Svetov article Sun2016222 This paper presents the earth science program SinoProbe in China, especially the deep continental scientific drilling equipment: "Crust 1" 10k ultra-deep scientific drilling rig and 4 indigenous key equipment: Topdrive system, Pipe handler, Hydraulic catwalk and Iron roughneck. These equipment can save auxiliary time, improve drilling efficiency and reduce labor intensity. Components and technical parameters were also introduced. "Crust 1" was deployed to drill through the Cretaceous continental strata of continental scientific drilling well: Songliao Basin Drilling Project (CCSD-SKII), which is the deepest scientific drilling program in China. Casing program was also introduced in this paper. Automated equipment performs a critical function in CCSD-SKII, the application can provide experience for furthermore scientific drilling program with designed well depth over 10,000 m in China. © 2016 Elsevier B.V.. 2016 English 09204105 10.1016/j.petrol.2016.04.003 Journal of Petroleum Science and Engineering 145 Elsevier B.V. 222-229 College of Construction Engineering, Jilin University, Changchun, 130026, China; Laboratory of Open Research on Complex Conditions Drilling, Jilin University, Changchun, 130026, China Application programs; Auxiliary equipment; Drilling rigs; Equipment; Hydraulic machinery, Catwalk; Crust 1; Drilling projects; Iron roughneck; Topdrive; Ultra-deep drilling, Drilling equipment, Chinese Continental Scientific Drilling Project; Cretaceous; drilling; drilling rig; hydrocarbon exploration, China; Songliao Basin https://www.scopus.com/inward/record.uri?eid=2-s2.0-84963944095&doi=10.1016%2fj.petrol.2016.04.003&partnerID=40&md5=4a8e233d415b01bab86aa60b1fc65c19 cited By 17 Y. Sun F. Zhang Q. Wang K. Gao article Sun20161016 Seismic attenuation and velocity dispersion are potentially able to reveal the rock physical properties of the subsurface. Conventionally, a frequency-independent quality factor (Q) is measured. This Q is equivalent to the total velocity dispersion in a seismic record and is inadequate for analysing the attenuation mechanism or rock physical properties. Here a new method is proposed to extract the velocity dispersion curves so that more attributes can be obtained from full-waveform multichannel sonic logging data, especially the critical frequency (fc) if it is within the bandwidth of the data. This method first decomposes the seismic data into a series of frequency components, computes the semblance of each frequency component for different velocity values, cross-correlates the semblance matrices of adjacent frequency components to get the velocity gradients, and finally integrates to obtain a velocity dispersion curve. Results of this method are of satisfactory accuracy and robustness. This method is applied to the data acquired in Mallik 5L-38 gas hydrate research well in Mackenzie Delta, Northwest Territories, Canada. The observed P-wave velocity dispersion compares well with the geological setting. In the gas hydrate zone (about 900 m–1100 m), high concentration of gas hydrate causes very strong velocity dispersion and a distinct fc at about 15 kHz, likely due to strong scattering of centimetre-scale inclusions of gas hydrate; concurrently, water flow in connected cracks in some ranges of this zone adds a large part of velocity dispersion and a dimmer fc at about 9.5 kHz. Immediate underneath the gas hydrate zone, abundant free water in weakly laminated sediments causes quite strong velocity dispersion and an fc at about 6.5 kHz. Velocity dispersion is mild and without an obvious fc in sediments above the gas hydrate zone. © 2016 European Association of Geoscientists & Engineers 2016 English 00168025 10.1111/1365-2478.12410 Geophysical Prospecting 64 Blackwell Publishing Ltd 1016-1029 State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum-Beijing, Beijing, 102249, China; Department of Earth Sciences, University of Toronto, Toronto, ON M5S 3B1, Canada; Department of Geological Sciences, University of Texas at Austin, Austin, TX 78712, United States 4 Acoustic logging; Flow of water; Gas hydrates; Gases; Hydration; Physical properties; Seismic waves; Seismology; Velocity; Wave propagation, Critical frequencies; Frequency components; Frequency independent; Geological setting; Laminated sediments; Rock physical properties; Seismic attenuation; Velocity dispersion, Dispersion (waves), data acquisition; gas hydrate; logging (geophysics); P-wave; Q factor; rock property; seismic attenuation; seismic velocity; wave dispersion; waveform analysis, Canada; Mackenzie Delta; Northwest Territories https://www.scopus.com/inward/record.uri?eid=2-s2.0-84977559993&doi=10.1111%2f1365-2478.12410&partnerID=40&md5=be1720ff72057437823d0632c479edf8 cited By 4 L.F. Sun B. Milkereit N. Tisato article Sharma20161549 Over the last two decades, the flowing fluid electric conductivity (FFEC) logging method has been applied in boreholes in the well-testing mode to evaluate the transmissivity, hydraulic head, and formation water electrical conductivity as a function of depth with a resolution of about 10–20 cm. FFEC profiles along the borehole are obtained under both shut-in and pumping conditions in a logging procedure that lasts only 3 or 4 days. A method for analyzing these FFEC logs has been developed and successfully employed to obtain formation parameters in a number of field studies. The present paper concerns the analysis of a unique set of FFEC logs that were taken from a deep borehole reaching down to 2.5 km at Outokumpu, Finland, over a 6-year time period. The borehole intersects paleoproterozoic metasedimentary, granitoid, and ophiolite-derived rocks. After the well was drilled, completed, and cleaned up, FFEC logs were obtained after 7, 433, 597, 948, and 2036 days. In analyzing these five profiles, we discovered the need to account for salinity diffusion from water in the formation to the borehole. Analysis results include the identification of 15 hydraulically conducting zones along the borehole, the calculation of flow rates associated with these 15 zones, as well as the estimation of the variation of formation water electrical conductivity as a function of depth. The calculated flow rates were used to obtain the tentative hydraulic conductivity values at these 15 depth levels. © 2015, Springer-Verlag Berlin Heidelberg. Article 2016 English 14373254 10.1007/s00531-015-1268-x International Journal of Earth Sciences 105 Springer Verlag 1549 – 1562 5 Finland; Outokumpu; Pohjois-Karjala; borehole logging; deep drilling; diffusion; electrical conductivity; formation water; hydraulic conductivity; hydraulic structure; monitoring; salinity; well logging https://www.scopus.com/inward/record.uri?eid=2-s2.0-84946762962&doi=10.1007%2fs00531-015-1268-x&partnerID=40&md5=c4f1a82fb2ce682c77f659588ac65df1 Cited by: 8 Prabhakar Sharma Chin-Fu Tsang Ilmo T. Kukkonen Auli Niemi article Bertini2016201 Lake Ohrid (Balkan peninsula) is the oldest European extant lake and one of the deepest and largest. Such a unique, terrestrial natural archive is especially relevant for both paleoenvironmental and paleoclimatic reconstructions but also for genetic studies. In the frame of the International Continental Scientific Drilling Program (ICDP), a deep drilling campaign was carried out within the scope of the Scientific Collaboration on Past Speciation Conditions in Lake Ohrid (SCOPSCO) project in 2013. Here, we present the summary of palynological analyses carried out in the upper 200 m of the overall 569 m long DEEP site sediment succession from the central part of the lake. These studies, performed by an international palynological team, document the main floristic, vegetation and climate changes during the last ca 500 kyr, at a millennial-scale resolution (~1.6 kyr). The continuous sediment infill permitted to trace multiple non-forested/ forested phases as a response to Glacial/Interglacial cycles as well as to sub-Milankovitch climate changes. The pollen record, corresponding with marine isotope stages MIS 13 to MIS 1, points to a progressive change from cooler and wetter to warmer and drier interglacials. New palynological studies are underway to reconstruct vegetational and climatic conditions over older intervals as well as to obtain high resolution data for some key intervals such as MIS 5-6, MIS 11-12, MIS 35-42. The complete record of changes in flora composition and vegetation during both glacials and interglacials will furnish indispensable insights for understanding the role of refugia, ecosystem resilience and maintenance of terrestrial biodiversity in the Mediterranean area. Article 2016 English 22797327 Alpine and Mediterranean Quaternary 29 AIQUA - Associazione Italiana per lo Studio del Quaternario 201 – 210 Dipartimento di Scienze della Terra, Università di Firenze, Firenze, Italy; Dipartimento di Biologia Ambientale, Università di Roma La Sapienza, Roma, Italy; Département de Préhistoire, Muséum national d'Histoire naturelle, Institut de Paléontologie Humaine, Paris, France; Palaeoecology, Department of Physical Geography, Utrecht University, Utrecht, Netherlands; Faculty of Geology and Geoenvironment, National and Kapodistrian University of Athens, Athens, Greece; Institute of Earth Sciences, Heidelberg University, Heidelberg, Germany; CNRS UMR 5554, Institut des Sciences de l'Evolution, Université de Montpellier, Montpellier, France; Dipartimento di Scienze della Vita, Università di Modena e Reggio Emilia, Modena, Italy; Institute of Geology and Mineralogy, University of Cologne, Cologne, Germany; Dipartimento di Scienze della Terra, University of Pisa, Pisa, Italy 2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85006894243&partnerID=40&md5=ea50e2df06681fa4ea789f852cd51450 Cited by: 10 Adele Bertini Laura Sadori Nathalie Combourieu-Nebout Timme H. Donders Katerina Kouli Andreas Koutsodendris Sebastien Joannin Alessia Masi Anna Maria Mercuri Konstantinos Panagiotopoulos Odile Peyron Gaia Sinopoli Paola Torri Giovanni Zanchetta Alexander Francke Bernd Wagner article Zanchetta20162757 The DEEP site sediment sequence obtained during the ICDP SCOPSCO project at Lake Ohrid was dated using tephrostratigraphic information, cyclostratigraphy, and orbital tuning through the marine isotope stages (MIS) 15-1. Although this approach is suitable for the generation of a general chronological framework of the long succession, it is insufficient to resolve more detailed palaeoclimatological questions, such as leads and lags of climate events between marine and terrestrial records or between different regions. Here, we demonstrate how the use of different tie points can affect cyclostratigraphy and orbital tuning for the period between ca. 140 and 70 ka and how the results can be correlated with directly/indirectly radiometrically dated Mediterranean marine and continental proxy records. The alternative age model presented here shows consistent differences with that initially proposed by Francke et al. (2015) for the same interval, in particular at the level of the MIS6-5e transition. According to this new age model, different proxies from the DEEP site sediment record support an increase of temperatures between glacial to interglacial conditions, which is almost synchronous with a rapid increase in sea surface temperature observed in the western Mediterranean. The results show how a detailed study of independent chronological tie points is important to align different records and to highlight asynchronisms of climate events. Moreover, Francke et al. (2016) have incorporated the new chronology proposed for tephra OH-DP-0499 in the final DEEP age model. This has reduced substantially the chronological discrepancies between the DEEP site age model and the model proposed here for the last glacial-interglacial transition. © 2016 Author(s). Article 2016 English 17264170 10.5194/bg-13-2757-2016 Biogeosciences 13 Copernicus GmbH 2757 – 2768 Dipartimento di Scienze della Terra, University of Pisa, Pisa, Italy; Institute of Environmental Geology and Geoengineering, IGAG-CNR, Montelibretti, Rome, Italy; Institute of Geology and Mineralogy, University of Cologne, Cologne, Germany; Dipartimento di Scienze della Terra e Geoambientali, University of Bari, Bari, Italy; Institute of Geological Sciences and Oeschger, Centre for Climate Change Research, University of Bern, Bern, Switzerland; Dipartimento di Biologia Ambientale, University of Roma 'La Sapienza', Roma, Italy; Centre for Environmental Geochemistry, School of Geography, University of Nottingham, Nottingham, United Kingdom; NERC Isotope Geosciences Facilities, British Geological Survey, Keyworth, Nottingham, United Kingdom 9 Lake Ohrid; Mediterranean Sea; age determination; cyclostratigraphy; glacial-interglacial cycle; marine isotope stage; marine record; Ocean Drilling Program; paleoclimate; proxy climate record; radiometric method; tephra; tephrochronology https://www.scopus.com/inward/record.uri?eid=2-s2.0-84969761382&doi=10.5194%2fbg-13-2757-2016&partnerID=40&md5=adaecfb39d6458abc6357ecf486c9f39 Cited by: 28; All Open Access, Gold Open Access, Green Open Access Giovanni Zanchetta Eleonora Regattieri Biagio Giaccio Bernd Wagner Roberto Sulpizio Alex Francke Hendrik Vogel Laura Sadori Alessia Masi Gaia Sinopoli Jack H. Lacey Melanie J. Leng Niklas Leicher article Hainzl20162575 The West Bohemia/Vogtland region, central Europe, is well known for its repeating swarm activity. However, the latest activity in 2014, although spatially overlapping with previous swarm activity, consisted of three classical aftershock sequences triggered by ML3.5, 4.4, and 3.5 events. To decode the apparent system change from swarm-type to mainshock-aftershock characteristics, we have analyzed the details of the major ML4.4 sequence based on focal mechanisms and relocated earthquake data. Our analysis shows that the mainshock occurred with rotated mechanism in a step over region of the fault plane, unfavorably oriented to the regional stress field. Most of its intense aftershock activity occurred in-plane with classical characteristics such as (i) the maximum magnitude of the aftershocks is significantly less than the mainshock magnitude and (ii) the decay can be well fitted by the Omori-Utsu law. However, the absolute number of aftershocks and the fitted Omori-Utsu c and p parameters are much larger than for typical sequences. By means of the epidemic-type aftershock sequence model, we show that an additional aseismic source with an exponentially decaying strength triggered a large fraction of the aftershocks. Corresponding pore pressure simulations with an exponentially decreasing flow rate of the fluid source show a good agreement with the observed spatial migration front of the aftershocks extending approximately with log(t). Thus, we conclude that the mainshock opened fluid pathways from a finite fluid source into the fault plane explaining the unusual high rate of aftershocks, the migration patterns, and the exponential decrease of the aseismic signal. ©2016. American Geophysical Union. All Rights Reserved. Article 2016 English 21699313 10.1002/2015JB012582 Journal of Geophysical Research: Solid Earth 121 Blackwell Publishing Ltd 2575 – 2590 4 Bohemia; Czech Republic; Germany; Vogtland; aftershock; earthquake magnitude; earthquake swarm; fault plane; focal mechanism; stress field https://www.scopus.com/inward/record.uri?eid=2-s2.0-84963647496&doi=10.1002%2f2015JB012582&partnerID=40&md5=85b48ca52c4eb8069206deca2a37ba3d Cited by: 41; All Open Access, Green Open Access S. Hainzl T. Fischer H. Čermáková M. Bachura J. Vlček article Lay20168792 The plate-bounding Alpine Fault in New Zealand is an 850 km long transpressive continental fault zone that is late in its earthquake cycle. We have acquired and processed reflection seismic data to image the subsurface around the main drill site of the Deep Fault Drilling Project (DFDP-2). The resulting velocity models and seismic images of the upper 5 km show complex subsurface structures around the Alpine Fault zone. The most prominent feature is a strong reflector at depths of 1.5–2.2 km with an apparent dip of 48° to the southeast below the DFDP-2 borehole, which we assume to be the main trace of the Alpine Fault. Above the main reflector, parallel reflectors suggest the presence of a ∼600 m wide damage zone. Additionally, subparallel reflectors are imaged that we interpret as secondary branches of the main fault zone. Conjugate faults imaged by the data show the complexity of the subsurface. The derived P wave velocity model reveals a 300–600 m thick sedimentary layer with velocities of ∼2.3 km/s above a schist basement with velocities of 4.5–5.5 km/s. A low-velocity layer can be observed within the basement at 0.8–2 km depth. A small-scale low-velocity anomaly appears at the top of the basement that can be correlated to the fault zone. The results provide a reliable basis for a seismic characterization of the DFDP-2 drill site that can be used for further structural and geological investigations of the architecture of the Alpine Fault in this area. ©2016. American Geophysical Union. All Rights Reserved. 2016 English 21699313 10.1002/2016JB013534 Journal of Geophysical Research: Solid Earth 121 Blackwell Publishing Ltd 8792-8812 Institute of Geophysics and Geoinformatics, TU Bergakademie Freiberg, Freiberg, Germany; Department of Geology, University of Otago, Dunedin, New Zealand; GNS Science, Lower Hutt, New Zealand; Department of Physics, University of Alberta, Edmonton, AB, Canada 12 fault zone; P-wave; prestack migration; seismic data; seismic reflection; seismic tomography; seismic velocity; structural geology; transpression, Alpine Fault Zone; New Zealand; South Island; West Coast [South Island]; Whataroa https://www.scopus.com/inward/record.uri?eid=2-s2.0-85007004345&doi=10.1002%2f2016JB013534&partnerID=40&md5=0e0a6fc98d3c2033abb581da5e8f5526 cited By 16 V. Lay S. Buske A. Lukacs A.R. Gorman S. Bannister D.R. Schmitt article Johnson2016220 African climate is generally considered to have evolved towards progressively drier conditions over the past few million years, with increased variability as glacial-interglacial change intensified worldwide. Palaeoclimate records derived mainly from northern Africa exhibit a 100,000-year (eccentricity) cycle overprinted on a pronounced 20,000-year (precession) beat, driven by orbital forcing of summer insolation, global ice volume and long-lived atmospheric greenhouse gases. Here we present a 1.3-million-year-long climate history from the Lake Malawi basin (10°-14° S in eastern Africa), which displays strong 100,000-year (eccentricity) cycles of temperature and rainfall following the Mid-Pleistocene Transition around 900,000 years ago. Interglacial periods were relatively warm and moist, while ice ages were cool and dry. The Malawi record shows limited evidence for precessional variability, which we attribute to the opposing effects of austral summer insolation and the temporal/spatial pattern of sea surface temperature in the Indian Ocean. The temperature history of the Malawi basin, at least for the past 500,000 years, strongly resembles past changes in atmospheric carbon dioxide and terrigenous dust flux in the tropical Pacific Ocean, but not in global ice volume. Climate in this sector of eastern Africa (unlike northern Africa) evolved from a predominantly arid environment with high-frequency variability to generally wetter conditions with more prolonged wet and dry intervals. © 2016 Macmillan Publishers Limited, part of Springer Nature. 2016 English 00280836 10.1038/nature19065 Nature 537 Nature Publishing Group 220-224 Large Lakes Observatory, Department of Earth and Environmental Sciences, University of Minnesota Duluth, Duluth, MN 55812, United States; Department of Geosciences, University of Massachusetts Amherst, Amherst, MA 01003, United States; Department of Geology and Planetary Science, University of Pittsburgh, Pittsburgh, PA 15260, United States; Department of Earth and Planetary Sciences, Faculty of Science and Engineering, Macquarie University, Sydney, NSW 2109, Australia; Department of Civil and Environmental Engineering, University of Notre Dame, 257 Fitzpatrick Hall, Notre Dame, IN 46556, United States; Departamento de Química Ambiental, Centro de Investigación en Biodiversidad y Ambientes Sustentables, Universidad Católica de la Santísima Concepción, Casilla, 297, Chile; Berkeley Geochronology Center, 2455 Ridge Road, Berkeley, CA 94709, United States; Earth Sciences Department, Syracuse University, Heroy Geology Laboratory, Syracuse, NY 13244, United States; NIOZ Netherlands Institute for Sea Research, Department of Marine Microbiology and Biogeochemistry, Utrecht University, PO Box 591790, Netherlands; Faculty of Geosciences, Department of Earth Sciences, Utrecht University, PO Box 80.0213508, Netherlands; Chevron Corporation, 1400 Smith Street, Houston, TX 77002, United States 7619 carbon dioxide; rain; alkane; calcium; carbon dioxide; dust; ice; rain; wax, arid environment; carbon dioxide; climate conditions; glacial-interglacial cycle; global climate; greenhouse gas; insolation; orbital forcing; paleoclimate; proxy climate record; sea surface temperature; spatiotemporal analysis; terrigenous deposit, Article; climate; climate change; Indian Ocean; interglacial; lake sediment; Malawi; Northern Hemisphere; paleoclimate; priority journal; sea surface temperature; summer; sunlight; thermoregulation; Africa; analysis; atmosphere; chemistry; desert climate; dust; history; lake; plant; plant leaf; season; temperature, East Africa; East African Lakes; Indian Ocean; Lake Malawi; Pacific Ocean, Africa, Eastern; Alkanes; Atmosphere; Calcium; Carbon Dioxide; Climate; Desert Climate; Dust; History, Ancient; Ice; Indian Ocean; Lakes; Malawi; Plant Leaves; Plants; Rain; Seasons; Temperature; Waxes https://www.scopus.com/inward/record.uri?eid=2-s2.0-84984661286&doi=10.1038%2fnature19065&partnerID=40&md5=a9ecdd27d64949e12065454dd4a6ec0e cited By 67 T.C. Johnson J.P. Werne E.T. Brown A. Abbott M. Berke B.A. Steinman J. Halbur S. Contreras S. Grosshuesch A. Deino C.A. Scholz R.P. Lyons S. Schouten J.S.S. Damsté article Ikari20161660 The evolution of fault strength during the seismic cycle plays a key role in the mode of fault slip, nature of earthquake stress drop, and earthquake nucleation. Laboratory-based rate- and state-dependent friction (RSF) laws can describe changes in fault strength during slip, but the connections between fault strength and the mechanisms that dictate the mode of failure, from aseismic creep to earthquake rupture, remain poorly understood. The empirical nature of RSF laws remains a drawback to their application in nature. Here we analyze an extensive data set of friction constitutive parameters with the goal of illuminating the microphysical processes controlling RSF. We document robust relationships between: (1) the initial value of sliding (or kinetic) friction, (2) RSF parameters, and (3) the time rates of frictional strengthening (aging). We derive a microphysical model based on asperity contact mechanics and show that these relationships are dictated by: (1) an activation energy that controls the rate of asperity growth by plastic creep, and (2) an inverse relationship between material hardness and the activation volume of plastic deformation. Collectively, our results illuminate the physics expressed by the RSF parameters, and which describe the absolute value of frictional strength and its dependence on time and slip rate. Moreover, we demonstrate that seismogenic fault behavior may be dictated by the interplay between grain properties and ambient conditions controlling the local shear strength of grain-scale asperity contacts. © 2016. American Geophysical Union. All Rights Reserved. 2016 English 15252027 10.1002/2016GC006286 Geochemistry, Geophysics, Geosystems 17 Blackwell Publishing Ltd 1660-1677 MARUM, Center for Marine Environmental Sciences, University of Bremen, Bremen, D-28359, Germany; Department of Geosciences, Pennsylvania State University, University Park, PA, United States; School of Geology and Geophysics, University of Oklahoma, Norman, OK, United States 5 Activation energy; Chemical activation; Creep; Deformation; Earthquakes; Faulting; Friction; Geophysics; Shear strength; Tribology, Ambient conditions; Constitutive parameters; Earthquake nucleation; Frictional strength; Inverse relationship; Microphysical models; Microphysical process; Seismogenic faults, Fault slips, asperity; creep; earthquake mechanism; earthquake rupture; fault gouge; fault slip; fault zone; plastic deformation; shear strength; tectonic evolution; tectonic setting https://www.scopus.com/inward/record.uri?eid=2-s2.0-84966415526&doi=10.1002%2f2016GC006286&partnerID=40&md5=c542bae26ad4dd71b430127b8df45544 cited By 64 M.J. Ikari B.M. Carpenter C. Marone article deWet201656 Previous periods of extreme warmth in Earth's history are of great interest in light of current and predicted anthropogenic warming. Numerous so called "super interglacial" intervals, with summer temperatures significantly warmer than today, have been identified in the 3.6 million year (Ma) sediment record from Lake El'gygytgyn, northeast Russia. To date, however, a high-resolution paleotemperature reconstruction from any of these super interglacials is lacking. Here we present a paleotemperature reconstruction based on branched glycerol dialkyl glycerol tetraethers (brGDGTs) from Marine Isotope Stages (MIS) 35 to MIS 29, including super interglacial MIS 31. To investigate this period in detail, samples were analyzed with an unprecedented average sample resolution of 500 yrs from MIS 33 to MIS 30. Our results suggest the entire period currently defined as MIS 33-31 (~1114-1062 kyr BP) was characterized by generally warm and highly variable conditions at the lake, at times out of phase with Northern Hemisphere summer insolation, and that cold "glacial" conditions during MIS 32 lasted only a few thousand years. Close similarities are seen with coeval records from high southern latitudes, supporting the suggestion that the interval from MIS 33 to MIS 31 was an exceptionally long interglacial (Teitler et al., 2015). Based on brGDGT temperatures from Lake El'gygytgyn (this study and unpublished results), warming in the western Arctic during MIS 31 was matched only by MIS 11 during the Pleistocene. © 2016 Elsevier B.V. 2016 English 0012821X 10.1016/j.epsl.2015.12.021 Earth and Planetary Science Letters 436 Elsevier 56-63 Department of Geosciences, University of Massachusetts Amherst, Amherst, MA 01003, United States Glacial geology; Glycerol; Isotopes, Arctic; Branched GDGT; Marine isotope stages; Paleoclimatology; Super interglacial, Lakes, interglacial; marine isotope stage; Northern Hemisphere; paleoclimate; paleotemperature; Pleistocene, Arctic; Chukchi; Elgygytgyn Lake; Russian Federation https://www.scopus.com/inward/record.uri?eid=2-s2.0-84953439336&doi=10.1016%2fj.epsl.2015.12.021&partnerID=40&md5=26410fe7f023129281e736e5d911beba cited By 22 G.A. Wet I.S. Castañeda R.M. DeConto J. Brigham-Grette article hedin_3d_2016 2016 oct en 00401951 10.1016/j.tecto.2015.12.013 Tectonophysics 689 40--55 http://linkinghub.elsevier.com/retrieve/pii/S0040195115006769 Peter Hedin Bjarne Almqvist Théo Berthet Christopher Juhlin Helge Simon Rüdiger Giese Felix Krauß Jan-Erik Rosberg Per-Gunnar Alm article Qin2024168 Article 2016 Acta Geologica Sinica 90 2109-2122 09 Z. Xu W. Yang J. Yang Z. An C. Wang H. Li J. Liu D. Su B. He D. Wang W. Zhang X. Zhang article Xi2016172 The Songliao Basin is the largest non-marine oil-bearing basin in China. Because of the absence of substantial evidence, the hypothesis of seawater incursion events into the Songliao Basin remains controversial. The presence of marine fossils could provide direct proof to support this supposition. Here, we report new discoveries of foraminifera, calcareous nannofossils, brackish dinoflagellates, and other marine and brackish-water fossils to support the suggestion of seawater incursion events in the Songliao Basin. Relatively abundant benthic and planktonic foraminifera, calcareous nannofossils, marine and brackish-water dinoflagellates, fish, and bivalves have been discovered in Members 1 and 2 of the Nenjiang Formation, a few foraminifera and brackish-water dinoflagellates have been found in the lower Qingshankou Formation, and just a few brackish-water bivalves have been found in the uppermost Qingshankou Fm. Based on the presence of marine molecular fossils and other evidence, we suggest that relatively large seawater incursion events occurred during the sedimentation of the lower Nenjiang Fm., relatively smaller seawater incursions occurred during the deposition of the lower Qingshankou Fm., and possibly a very small seawater incursion occurred during the sedimentation of the uppermost Qingshankou Fm. These seawater incursion events in the Songliao Basin were controlled by regional tectonic activity, evolution of the palaeo Songliao Lake, and global sea level change. These periodic seawater incursions brought marine biota into the palaeo Songliao Lake. © 2015 Elsevier Ltd. 2016 English 01956671 10.1016/j.cretres.2015.10.025 Cretaceous Research 62 Academic Press 172-182 State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences (Beijing), Xueyuan Lu 29, Haidian District, Beijing, 100083, China; State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, 39 East Beijing Road, Nanjing, Jiangsu, 210008, China; Exploration and Development Research Institute of Daqing Oil Field Corporation, Daqing, Heilongjiang, 163712, China; Universidade de Brasília, Instituto de Geociências, Campus Universitário Darcy Ribeiro, Brasília, DF, CEP 70.910-900, Brazil; Guangzhou Marine Geological Survey, Guangzhou, 510075, China biostratigraphy; bivalve; Cretaceous; dinoflagellate; fish; foraminifera; lacustrine environment; nanofossil; paleoenvironment; seawater, China; Songliao Basin, Bivalvia; Dinophyceae; Foraminifera https://www.scopus.com/inward/record.uri?eid=2-s2.0-84960813942&doi=10.1016%2fj.cretres.2015.10.025&partnerID=40&md5=b50263fc4834e6ada8de1855a46dfabb cited By 40 D. Xi W. Cao Q. Huang D.A. Do Carmo S. Li X. Jing Y. Tu J. Jia H. Qu J. Zhao X. Wan article Lin2025 Article 2016 10.16816/j.cnki.ksjx.2016.02.008 Mining & Processing Equipment 44 31-34+41 02 Y. Hu X. Yu H. Zhang X. Zhu M. Xiang article Kutterolf2016200 Lake Petén Itzá, northern Guatemala, lies within a hydrologically closed basin in the south-central area of the Yucatán Peninsula, and was drilled under the auspices of the International Continental Scientific Drilling Program (ICDP) in 2006. At 16°55′N latitude, the lake is ideally located for study of past climate and environmental conditions in the Neotropical lowlands. Because of its great depth (>160 m), Lake Petén Itzá has a record of continuous sediment accumulation that extends well into the late Pleistocene. A key obstacle to obtaining long climate records from the region is the difficulty of establishing a robust chronology beyond ∼40 ka, the limit of 14C dating. Tephra layers within the Lake Petén Itzá sediments, however, enable development of age/depth relations beyond 40 ka. Ash beds from large-magnitude, Pleistocene-to-Holocene silicic eruptions of caldera volcanoes along the Central American Volcanic Arc (CAVA) were found throughout drill cores collected from Lake Petén Itzá. These ash beds were used to establish a robust chronology extending back 400 ka. We used major- and trace-element glass composition to establish 12 well-constrained correlations between the lacustrine tephra layers in Lake Petén Itzá sediments and dated deposits at the CAVA source volcanoes, and with their marine equivalents in eastern Pacific Ocean sediments. The data also enabled revision of eight previous determinations of erupted volumes and masses, and initial estimates for another four eruptions, as well as the designation of source areas for 14 previously unknown eruptions. The new and revised sedimentation rates for the older sediment successions identify the interglacial of MIS5a between 84 and 72 ka, followed by a stadial between 72 and 59 ka that corresponds to MIS4. We modified the age models for the Lake Petén Itzá sediment sequences, extended the paleoclimate and paleoecological record for this Neotropical region to ∼400 ka, and determined the magnitude and timing of CAVA eruptions. © 2016 Elsevier Ltd Article 2016 English 02773791 10.1016/j.quascirev.2016.08.023 Quaternary Science Reviews 150 Elsevier Ltd 200 – 220 GEOMAR Helmholtz Center for Ocean Research Kiel, Kiel, 24148, Germany; Institute of Geological Sciences and Oeschger Centre for Climate Change Research, University of Bern, Switzerland; Department of Earth Sciences, University of Geneva, Rue des Maraichers 13, Geneva, 1205, Switzerland; Department of Geological Sciences and Land Use and Environmental Change Institute (LUECI), University of Florida, Gainesville, FL 32611, United States; Department of Earth Sciences, University of Cambridge, United Kingdom; Swiss Federal Institute of Technology, ETH, Zurich, 8092, Switzerland; Institute of Geology, Universidad Nacional Autónoma de México, Mexico; Institute of Geosystems and Bioindication (IGeo), Technische Universität Braunschweig, Germany; Institute of Earth Sciences, Academia Sinica, Taipei, 11529, Taiwan Guatemala [Central America]; Lake Peten Itza; Pacific Ocean; Pacific Ocean (East); Peten; Yucatan Peninsula; Sediments; Trace elements; Volcanoes; CAVA; Explosive volcanism; ICDP; Paleoclimates; Tephrochronology; caldera; drilling; explosive volcanism; island arc; lowland environment; Neotropical Region; paleoclimate; Pleistocene; sediment analysis; sedimentation; tephrochronology; volcanic eruption; Lakes https://www.scopus.com/inward/record.uri?eid=2-s2.0-84984621696&doi=10.1016%2fj.quascirev.2016.08.023&partnerID=40&md5=fd7408c4491b6322e26e1c2dc71bdb49 Cited by: 36; All Open Access, Bronze Open Access S. Kutterolf J.C. Schindlbeck F.S. Anselmetti D. Ariztegui M. Brenner J. Curtis D. Schmid D.A. Hodell A. Mueller L. Pérez W. Pérez A. Schwalb M. Frische K.-L. Wang article 2016 10.13712/j.cnki.dzykt.2016.05.014 Geology and Exploration 52 931-936 5 W. Zheng X. Wu Y. Huang W. Wang D. Wu H. Huang article Liu201641 Grain-size compositions of lake sediments can provide direct information on changes in transporting mechanism and sedimentary environment. Various grain-size parameters have been employed to reconstruct hydrological conditions within the lake and dust influx from outside the lake. Here we present the grain-size results of a 5-m core retrieved from Lake Qinghai, northeastern Tibetan Plateau in order to address the links between Holocene depositional process and climatic change. Our results indicate that two parameters (skewness and grain-size ratio of 8-50/2-8 μm) are sensitive to hydrodynamic changes in Lake Qinghai, which are further linked to the strength of the Asian summer monsoon. Variations of these two parameters reveal that summer monsoon intensity weakened gradually from early to late Holocene, superimposed by persistent centennial variability with dominant periods at 0.35, 0.23 and 0.12 kyr. Comparison of grain-size variations with solar activities and North Atlantic cooling events reveals that solar forcing likely plays an important role in driving centennial monsoon variability. © 2016 Elsevier B.V. Article 2016 English 00310182 10.1016/j.palaeo.2016.02.005 Palaeogeography, Palaeoclimatology, Palaeoecology 449 Elsevier B.V. 41 – 51 Atlantic Ocean; Atlantic Ocean (North); China; Qinghai; Qinghai Lake; climate change; depositional environment; grain size; Holocene; hydrodynamics; lacustrine deposit; monsoon; reconstruction; solar activity https://www.scopus.com/inward/record.uri?eid=2-s2.0-84959227439&doi=10.1016%2fj.palaeo.2016.02.005&partnerID=40&md5=50164af5d344c1bcdc8fdf19b4f9a003 Cited by: 87; All Open Access, Bronze Open Access Xingxing Liu Jef Vandenberghe ZhiSheng An Ying Li Zhangdong Jin Jibao Dong Youbin Sun article Schuessler20168548 We investigated the iron isotope signatures of dissolved Fe in the water of the Wettinquelle mineral spring (Bad Brambach, Germany) by time series sampling covering seismically active periods related to tectonic activity near the Eger Rift system in central Europe. Our objective was to test whether Fe isotopes trace earthquake-induced abiotic and biotic changes in the fluid/rock interaction of the deep, fissured, granitic aquifer. We found that the dissolved Fe isotope signatures in spring water are distinct from the granitic source signature (δ56Fe = +0.09‰). Particularly, we discovered that water δ56Fe values are remarkably stable (−0.01 ± 0.11‰, 2SD, n = 4) before and during a strong seismic swarm period in 2000 (local magnitudes ML > 3), while O2 and H2 concentrations in water decrease and dissolved Fe content increases. Later, recurring events of lower δ56Fe values down to −0.3‰ are observed in the period from 2001 to 2003 with intermittent seismic events (1 < ML < 3.2). The observations indicate a time lag between tectonic forcing and Fe isotope response. The role of abiotic fluid/rock interaction and Fe-utilizing bacteria identified in the mineral spring water on Fe isotope fractionation is discussed. We explain recurring changes toward isotopically lighter values by a combination of Fe dissolution from deep granite and admixture of isotopically light Fe generated by a complex combination of abiotic and biotic processes operating in the aquifer when disturbed by swarm earthquakes events. We propose a conceptual model scenario of earthquake-triggered changes in biogeochemical processes. ©2016. American Geophysical Union. All Rights Reserved. Article 2016 English 21699313 10.1002/2016JB013408 Journal of Geophysical Research: Solid Earth 121 Blackwell Publishing Ltd 8548 – 8568 12 Central Europe; Germany; aquifer; biochemistry; earthquake swarm; iron; isotopic fractionation; spring water; time series analysis https://www.scopus.com/inward/record.uri?eid=2-s2.0-85007035459&doi=10.1002%2f2016JB013408&partnerID=40&md5=4a38cb44ef09e58937003e146505e833 Cited by: 29; All Open Access, Bronze Open Access, Green Open Access Jan A. Schuessler Horst Kämpf Ulrich Koch Mashal Alawi article Niemeijer2016624 The Alpine Fault, New Zealand, is a major plate-bounding fault that accommodates 65-75% of the total relative motion between the Australian and Pacific plates. Here we present data on the hydrothermal frictional properties of Alpine Fault rocks that surround the principal slip zones (PSZ) of the Alpine Fault and those comprising the PSZ itself. The samples were retrieved from relatively shallow depths during phase 1 of the Deep Fault Drilling Project (DFDP-1) at Gaunt Creek. Simulated fault gouges were sheared at temperatures of 25, 150, 300, 450, and 600°C in order to determine the friction coefficient as well as the velocity dependence of friction. Friction remains more or less constant with changes in temperature, but a transition from velocity-strengthening behavior to velocity-weakening behavior occurs at a temperature of T = 150°C. The transition depends on the absolute value of sliding velocity as well as temperature, with the velocity-weakening region restricted to higher velocity for higher temperatures. Friction was substantially lower for low-velocity shearing (V < 0.3 μm/s) at 600°C, but no transition to normal stress independence was observed. In the framework of rate-and-state friction, earthquake nucleation is most likely at an intermediate temperature of T = 300°C. The velocity-strengthening nature of the Alpine Fault rocks at higher temperatures may pose a barrier for rupture propagation to deeper levels, limiting the possible depth extent of large earthquakes. Our results highlight the importance of strain rate in controlling frictional behavior under conditions spanning the classical brittle-plastic transition for quartzofeldspathic compositions. ©2016. The Authors. 2016 English 21699313 10.1002/2015JB012593 Journal of Geophysical Research: Solid Earth 121 Blackwell Publishing Ltd 624-647 Faculty of Geosciences, HPT Laboratory, Utrecht University, Utrecht, Netherlands; Geology and Geophysics, School of Environmental Sciences, University of Liverpool, Liverpool, United Kingdom; Department of Geology, University of Otago, Dunedin, New Zealand; School of Geography, Environment and Earth Sciences, Victoria University of Wellington, Wellington, New Zealand; GNS Science, Lower Hutt, New Zealand 2 earthquake rupture; fault; fault displacement; fault gouge; friction; hydrothermal system; plate tectonics; strain rate, Alpine Fault Zone; New Zealand; South Island https://www.scopus.com/inward/record.uri?eid=2-s2.0-84975691303&doi=10.1002%2f2015JB012593&partnerID=40&md5=031f2b796a9e14295cd2de0a853d713a cited By 34 A.R. Niemeijer C. Boulton V.G. Toy J. Townend R. Sutherland article Carpenter20161183 Interseismic recovery of fault strength (healing) following earthquake failure is a fundamental requirement of the seismic cycle and likely plays a key role in determining the stability and slip behavior of tectonic faults. We report on laboratory measurements of time- and slip-dependent frictional strengthening for natural and synthetic gouges to evaluate the role of mineralogy in frictional strengthening. We performed slide-hold-slide (SHS) shearing experiments on nine natural fault gouges and eight synthetic gouges at conditions of 20 MPa normal stress, 100% relative humidity (RH), large shear strain (~15), and room temperature. Phyllosilicate-rich rocks show the lowest rates of frictional strengthening. Samples rich in quartz and feldspar exhibit intermediate rates of frictional strengthening, and calcite-rich gouges show the largest values. Our results show that (1) the rates of frictional strengthening and creep relaxation scale with frictional strength, (2) phyllosilicate-rich fault gouges have low strength and healing characteristics that promote stable, aseismic creep, (3) most natural fault gouges exhibit intermediate rates of frictional strengthening, consistent with a broad range of fault slip behaviors, and (4) calcite-rich fault rocks show the highest rates of frictional strengthening, low values of dilation upon reshear, and high frictional strengths, all of which would promote seismogenic behavior. ©2016. American Geophysical Union. All Rights Reserved. 2016 English 21699313 10.1002/2015JB012136 Journal of Geophysical Research: Solid Earth 121 Blackwell Publishing Ltd 1183-1201 School of Geology and Geophysics, University of Oklahoma, Norman, OK, United States; Department of Geosciences and Energy Institute Center for Geomechanics, Geofluids, and Geohazards, Pennsylvania State University, University Park, PA, United States; MARUM, Center for Marine and Environmental Science, University of Bremen, Bremen, Germany 2 earthquake event; fault; fault gouge; friction; mineralogy; observational method; relative humidity; slip; stress https://www.scopus.com/inward/record.uri?eid=2-s2.0-84975763703&doi=10.1002%2f2015JB012136&partnerID=40&md5=67c0d815b6bee2faff738e6ee133c424 cited By 67 B.M. Carpenter M.J. Ikari C. Marone article Holtvoeth2016795 We present elemental, lipid biomarker and, in the supplement, compound-specific isotope (δ13C, δ2H) data for soils and leaf litter collected in the catchment of Lake Ohrid (Albania, Macedonia), as well as macrophytes, particulate organic matter and sediments from the lake itself. Lake Ohrid provides an outstanding archive of continental environmental change of at least 1.2 million years and the purpose of our study is to ground truth organic geochemical proxies that we developed in order to study past changes in the terrestrial biome. We show that soils dominate the lipid signal of the lake sediments rather than the vegetation or aquatic biomass. There is a strong imprint of suberin monomers on the composition of total lipid extracts and chain-length distributions of n-alkanoic acids, n-alcohols, ω-hydroxy acids and α, ω-dicarboxylic acids. Our end-member survey identifies that ratios of mid-chain length suberin-derived to long-chain length cuticular-derived alkyl compounds as well as their average chain length distributions can be used as new molecular proxies of organic matter sources to the lake. We tested these for the 8.2 ka event, a pronounced and widespread Holocene climate fluctuation. In SE Europe climate became drier and cooler in response to the event, as is clearly recognisable in the carbonate and organic carbon records of Lake Ohrid sediments. Our new proxies indicate biome modification in response to hydrological changes, identifying two phases of increased soil organic matter (OM) supply, first from soils with moderately degraded OM and then from more degraded soils. Our study demonstrates that geochemical fingerprinting of terrestrial OM should focus on the main lipid sources, rather than the living biomass. Both can exhibit climate-controlled variability, but are generally not identical. © Author(s) 2016. Article 2016 English 17264170 10.5194/bg-13-795-2016 Biogeosciences 13 Copernicus GmbH 795 – 816 3 Albania; Lake Ohrid; Macedonia [Southern Europe]; biomarker; biome; catchment; climate effect; environmental change; geochemistry; Holocene; inorganic carbon; leaf litter; paleoenvironment; sediment analysis; soil organic matter; vegetation history https://www.scopus.com/inward/record.uri?eid=2-s2.0-84958999351&doi=10.5194%2fbg-13-795-2016&partnerID=40&md5=5f1d86c87feee5267562c92833ee84de Cited by: 26; All Open Access, Gold Open Access, Green Open Access J. Holtvoeth D. Rushworth H. Copsey A. Imeri M. Cara H. Vogel T. Wagner G.A. Wolff article Mortimer2016110 The Cenozoic East African Rift System (EARS) is an exceptional example of active continental extension, providing opportunities for furthering our understanding of hydrocarbon plays within rifts. It is divided into structurally distinct western and eastern branches. The western branch comprises deep rift basins separated by transfer zones, commonly localised onto pre-existing structures, offering good regional scale hydrocarbon traps. At a basin-scale, local discrete inherited structures might also play an important role on fault localisation and hydrocarbon distribution. Here, we consider the evolution of the Central basin of the Malawi Rift, in particular the influence of pre-existing structural fabrics.Integrating basin-scale multichannel 2D, and high resolution seismic datasets we constrain the border, Mlowe-Nkhata, fault system (MNF) to the west of the basin and smaller Mbamba fault (MF) to the east and document their evolution. Intra basin structures define a series of horsts, which initiated as convergent transfers, along the basin axis. The horsts are offset along a NE-SW striking transfer fault parallel to and along strike of the onshore Karoo (Permo-Triassic) Ruhuhu graben. Discrete pre-existing structures probably determined its location and, oriented obliquely to the extension orientation it accommodated predominantly strike-slip deformation, with more slowly accrued dip-slip.To the north of this transfer fault, the overall basin architecture is asymmetric, thickening to the west throughout; while to the south, an initially symmetric graben architecture became increasingly asymmetric in sediment distribution as strain localised onto the western MNF. The presence of the axial horst increasingly focussed sediment supply to the west. As the transfer fault increased its displacement, so this axial supply was interrupted, effectively starving the south-east while ponding sediments between the western horst margin and the transfer fault. This asymmetric bathymetry and partitioned sedimentation continues to the present-day, overprinting the early basin symmetry and configuration. Sediments deposited earlier become increasingly dissected and fault juxtapositions changed at a small (10-100 m) scale. The observed influence of basin-scale transfer faults on sediment dispersal and fault compartmentalization due to pre-existing structures oblique to the extension orientation is relevant to analogous exploration settings. © 2016 Elsevier Ltd. 2016 English 02648172 10.1016/j.marpetgeo.2015.12.018 Marine and Petroleum Geology 72 Elsevier Ltd 110-121 Basin Structure Group, School of Earth and Environment, University of Leeds, Leeds, United Kingdom; Department of Earth Sciences, 011a Heroy Geology Laboratory, University of SyracuseNY 13244, United States; Institut f. Geowissenschaften, Universität Potsdam, Postdam, 14476, Germany Geologic models; Hydrocarbons; Sediments; Strike-slip faults, East African Rift; Existing structure; High resolution seismic; Hydrocarbon distribution; Normal faults; Sediment distribution; Strike-slip deformation; Structural inheritance, Fault slips, basin evolution; compartmentalization; deformation; extensional tectonics; hydrocarbon; normal fault; rift zone; sediment transport; strike-slip fault, East African Rift https://www.scopus.com/inward/record.uri?eid=2-s2.0-84955613486&doi=10.1016%2fj.marpetgeo.2015.12.018&partnerID=40&md5=74578c94e50a8e8b44c291f8b8b3153d cited By 21 E.J. Mortimer D.A. Paton C.A. Scholz M.R. Strecker article Wennrich2016221 Lake El'gygytgyn in Far East Russia is a 3.6 Myr old impact crater lake. Located in an area that has never been affected by Cenozoic glaciations nor desiccation, the unique sediment record of the lake represents the longest continuous sediment archive of the terrestrial Arctic. The surrounding crater is the only impact structure on Earth developed in mostly acid volcanic rocks. Recent studies on the impactite, permafrost, and sediment sequences recovered within the framework of the ICDP “El'gygytgyn Drilling Project” and multiple pre-site surveys yielded new insight into the bedrock origin and cratering processes as well as permafrost dynamics and the climate and environmental history of the terrestrial Arctic back to the mid-Pliocene. Results from the impact rock section recovered during the deep drilling clearly confirm the impact genesis of the El'gygytgyn crater, but indicate an only very reduced fallback impactite sequence without larger coherent melt bodies. Isotope and element data of impact melt samples indicate a F-type asteroid of mixed composition or an ordinary chondrite as the likely impactor. The impact event caused a long-lasting hydrothermal activity in the crater that is assumed to have persisted for c. 300 kyr. Geochemical and microbial analyses of the permafrost core indicate a subaquatic formation of the lower part during lake-level highstand, but a subaerial genesis of the upper part after a lake-level drop after the Allerød. The isotope signal and ion compositions of ground ice is overprinted by several thaw-freeze cycles due to variations in the talik underneath the lake. Modeling results suggest a modern permafrost thickness in the crater of c. 340 m, and further confirm a pervasive character of the talik below Lake El'gygytgyn. The lake sediment sequences shed new leight into the Pliocene and Pleistocene climate and environmental evolution of the Arctic. During the mid-Pliocene, significantly warmer and wetter climatic conditions in western Beringia than today enabled dense boreal forests to grow around Lake El'gygytgyn and, in combination with a higher nutrient flux into the lake, promoted primary production. The exceptional warmth during the mid-Pliocene is in accordance with other marine and terrestrial records from the Arctic and indicates a period of enhanced “Arctic amplification”. The favourable conditions during the mid-Pliocene were repeatedly interrupted by climate deteriorations, e.g., during Marine Isotope Stage (MIS) M2, when pollen data and sediment proxies indicate a major cooling and the onset of local permafrost around the lake. A gradual vegetation change after c. 3.0 Ma points to the onset of a long-term cooling trend during the Late Pliocene that culminated in major temperature drops, first during MIS G6, and later during MIS 104. These cold events coincide with the onset of an intensified Northern Hemisphere (NH) glaciation and the largest extent of the Cordilleran Ice Sheet, respectively. After the Pliocene/Pleistocene transition, local vegetation and primary production in Lake El'gygtygyn experienced a major change from relatively uniform conditions to a high-amplitude glacial-to-interglacial cyclicity that fluctuated on a dominant 41 kyr obliquity band, but changed to a 100 kyr eccentricity dominance during the Middle Pleistocene transition (MPT) at c. 1.2–0.6 Ma. Periods of exceptional warming in the Pleistocene record of Lake El'gygytgyn with dense boreal forests around and peaks of primary production in the lake are assigned to so-called “super-interglacial” periods. The occurrence of these super-interglacials well corresponds to collapses of the West Antarctic Ice Sheet (WAIS) recorded in ice-free periods in the ANDRILL core, which suggests strong intrahemispheric teleconnections presumably driven by changes in the thermocline ocean circulation. © 2016 Elsevier Ltd 2016 English 02773791 10.1016/j.quascirev.2016.03.019 Quaternary Science Reviews 147 Elsevier Ltd 221-244 Institute of Geology and Mineralogy, University of Cologne, Zuelpicher Str. 49a, Cologne, 50674, Germany; Institute of Geology and Petroleum Technologies, Kazan Federal University, Kremlyovskaya Str. 18, Kazan, 420008, Russian Federation; Free University Berlin, Institute of Geological Sciences, Palaeontology Section, Malteser Str. 74-100, Building D, Berlin, 12249, Germany; Arctic and Antarctic Research Institute, Bering Street 38, St. Petersburg, 199397, Russian Federation; St. Petersburg State University, Institute of Earth Sciences, 10 Line V.O., 33, St. Petersburg, 199178, Russian Federation; Alfred Wegener Institute for Polar and Marine Research, Am Alten Hafen 26, Bremerhaven, 27568, Germany; Department of Ecology and Environmental Science, Umeå University, Umeå, SE-901 87, Sweden; Department of Geology, Bowling Green State University, Bowling Green, OH 43403, United States; Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences, Telegrafenberg, Potsdam, 14473, Germany; Alfred Wegener Institute for Polar and Marine Research, Telegrafenberg A43, Potsdam, 14473, Germany; Earth and Space Sciences and Quaternary Research Center, University of Washington, Seattle, 98195-1310, United States; Northeast Interdisciplinary Scientific Research Institute, Far East Branch, Russian Academy of Sciences, Portovaya Street 16, Magadan, 685000, Russian Federation; Department of Lithospheric Research, University of Vienna, Althanstrasse 14, Vienna, 1090, Austria; Natural History Museum, Burgring 7, Vienna, 1010, Austria Amplification; Climate change; Drops; Dynamics; Fluorine; Forestry; Glacial geology; Glaciers; Ice; Isotopes; Permafrost; Rock drilling; Sediments; Structural geology; Vegetation; Volcanic rocks, Environmental evolution; Environmental variability; ICDP; Interglacial cyclicity; Interglacials; Mid-Pliocene; Pliocene; West antarctic ice sheets, Lakes, arctic environment; Beringia; climate variation; Cordilleran Ice Sheet; crater lake; environmental change; glacial-interglacial cycle; historical ecology; isotopic analysis; marine isotope stage; nutrient dynamics; paleoenvironment; permafrost; Pliocene-Pleistocene boundary; vegetation dynamics; warming, Chukchi; Elgygytgyn Lake; Russian Federation https://www.scopus.com/inward/record.uri?eid=2-s2.0-84962862643&doi=10.1016%2fj.quascirev.2016.03.019&partnerID=40&md5=bd2549582e59f23be42b025c3520ad5f cited By 23 V. Wennrich A.A. Andreev P.E. Tarasov G. Fedorov W. Zhao C.A. Gebhardt C. Meyer-Jacob J.A. Snyder N.R. Nowaczyk G. Schwamborn B. Chapligin P.M. Anderson A.V. Lozhkin P.S. Minyuk C. Koeberl M. Melles article Moore2016153 We compare frictional strengths in the temperature range 25-250 °C of fault gouge from SAFOD (CDZ and SDZ) with quartzofeldspathic wall rocks typical of the central creeping section of the San Andreas Fault (Great Valley sequence and Franciscan Complex). The Great Valley and Franciscan samples have coefficients of friction, μ > 0.35 at all experimental conditions. Strength is unchanged between 25° and 150 °C, but μ increases at higher temperatures, exceeding 0.50 at 250 °C. Both samples are velocity strengthening at room temperature but show velocity-weakening behavior beginning at 150 °C and stick-slip motion at 250 °C. These rocks, therefore, have the potential for unstable seismic slip at depth. The CDZ gouge, with a high saponite content, is weak (μ = 0.09-0.17) and velocity strengthening in all experiments, and μ decreases at temperatures above 150 °C. Behavior of the SDZ is intermediate between the CDZ and wall rocks: μ < 0.2 and does not vary with temperature. Although saponite is probably not stable at depths greater than ~3 km, substitution of the frictionally similar minerals talc and Mg-rich chlorite for saponite at higher temperatures could potentially extend the range of low strength and stable slip down to the base of the seismogenic zone. © 2016. 2016 English 01918141 10.1016/j.jsg.2016.06.005 Journal of Structural Geology 89 Elsevier Ltd 153-167 U.S. Geological Survey, Earthquake Science Center, 345 Middlefield Road, Mail Stop 977, Menlo Park, CA 94025, United States Landforms; Rocks; Slip forming; Stick-slip; Strike-slip faults, Franciscan Complex; Frictional strength; Great Valley sequence; SAFOD; San Andreas fault; Saponite, Minerals, creep; fault gouge; friction; rock; San Andreas Fault; saponite; seismic zone; slip; strength; strike-slip fault; temperature, California; Central Valley [California]; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-84975498333&doi=10.1016%2fj.jsg.2016.06.005&partnerID=40&md5=1a737f13c543a481f5b380fd011aa48e cited By 25 D.E. Moore D.A. Lockner S. Hickman article tsang_hydrologic_2016 Drilling of a deep borehole does not normally allow for hydrologic testing during the drilling period. It is only done when drilling experiences a large loss (or high return) of drilling fluid due to penetration of a large-transmissivity zone. The paper proposes the possibility of conducting flowing fluid electrical conductivity (FFEC) logging during the drilling period, with negligible impact on the drilling schedule, yet providing important information on depth locations of both high- and low-transmissivity zones and their hydraulic properties. The information can be used to guide downhole fluid sampling and post-drilling detailed testing of the borehole. The method has been applied to the drilling of a 2,500-m borehole at Åre, central Sweden, firstly when the drilling reached 1,600 m, and then when the drilling reached the target depth of 2,500 m. Results unveil eight hydraulically active zones from 300 m down to borehole bottom, with depths determined to within the order of a meter. Further, the first set of data allows the estimation of hydraulic transmissivity values of the six hydraulically conductive zones found from 300 to 1,600 m, which are very low and range over one order of magnitude. 2016 apr en 1431-2174, 1435-0157 10.1007/s10040-016-1405-z Hydrogeology Journal 24 1333--1341 6 http://link.springer.com/article/10.1007/s10040-016-1405-z Chin-Fu Tsang Jan-Erik Rosberg Prabhakar Sharma Théo Berthet Christopher Juhlin Auli Niemi article Adhikari2016 Subsurface microbial communities undertake many terminal electron-accepting processes, often simultaneously. Using a tritium-based assay, we measured the potential hydrogen oxidation catalyzed by hydrogenase enzymes in several subsurface sedimentary environments (Lake Van, Barents Sea, Equatorial Pacific, and Gulf of Mexico) with different predominant electron-acceptors. Hydrogenases constitute a diverse family of enzymes expressed by microorganisms that utilize molecular hydrogen as a metabolic substrate, product, or intermediate. The assay reveals the potential for utilizing molecular hydrogen and allows qualitative detection of microbial activity irrespective of the predominant electron-accepting process. Because the method only requires samples frozen immediately after recovery, the assay can be used for identifying microbial activity in subsurface ecosystems without the need to preserve live material. We measured potential hydrogen oxidation rates in all samples from multiple depths at several sites that collectively span a wide range of environmental conditions and biogeochemical zones. Potential activity normalized to total cell abundance ranges over five orders of magnitude and varies, dependent upon the predominant terminal electron acceptor. Lowest per-cell potential rates characterize the zone of nitrate reduction and highest per-cell potential rates occur in the methanogenic zone. Possible reasons for this relationship to predominant electron acceptor include (i) increasing importance of fermentation in successively deeper biogeochemical zones and (ii) adaptation of H2ases to successively higher concentrations of H2 in successively deeper zones. © 2016 Adhikari, Glombitza, Nickel, Anderson, Dunlea, Spivack, Murray, D'Hondt and Kallmeyer. 2016 English 1664302X 10.3389/fmicb.2016.00008 Frontiers in Microbiology 7 Frontiers Media S.A. MARUM - Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany; Geomicrobiology Group, Institute of Earth and Environmental Science, University of Potsdam, Potsdam, Germany; Center for Geomicrobiology, Department of Bioscience, Aarhus University, Aarhus C, Denmark; Helmholtz-Centre Potsdam - GFZ German Research Centre for Geosciences, Potsdam, Germany; Department of Earth and Environment, Boston University, Boston, MA, United States; Graduate School of Oceanography, University of Rhode Island, Kingston, RI, United States JAN hydrogen; hydrogenase; iron; manganese; sulfate, Article; ecosystem; enzyme assay; Gulf of Mexico; metabolic activity assay; microbial activity; microbial community; nonhuman; Pacific Ocean; radioactivity; sediment; temperature; Turkey (republic); water analysis https://www.scopus.com/inward/record.uri?eid=2-s2.0-84957954218&doi=10.3389%2ffmicb.2016.00008&partnerID=40&md5=4e2684f27d2246dc4f721d005bef0e1a cited By 14 R.R. Adhikari C. Glombitza J.C. Nickel C.H. Anderson A.G. Dunlea A.J. Spivack R.W. Murray S. D'Hondt J. Kallmeyer article Neugebauer201675 The new sediment record from the deep Dead Sea basin (ICDP core 5017-1) provides a unique archive for hydroclimatic variability in the Levant. Here, we present highresolution sediment facies analysis and elemental composition by micro-X-ray fluorescence (ìXRF) scanning of core 5017-1 to trace lake levels and responses of the regional hydroclimatology during the time interval from ca. 117 to 75 ka, i.e. the transition between the last interglacial and the onset of the last glaciation. We distinguished six major micro-facies types and interpreted these and their alterations in the core in terms of relative lake level changes. The two end-member facies for highest and lowest lake levels are (a) up to several metres thick, greenish sediments of alternating aragonite and detrital marl laminae (aad) and (b) thick halite facies, respectively. Intermediate lake levels are characterised by detrital marls with varying amounts of aragonite, gypsum or halite, reflecting lower-amplitude, shorter-term variability. Two intervals of pronounced lake level drops occurred at ∼110-1085 and ∼93-87±7 ka. They likely coincide with stadial conditions in the central Mediterranean (Melisey I and II pollen zones in Monticchio) and low global sea levels during Marine Isotope Stage (MIS) 5d and 5b. However, our data do not support the current hypothesis of an almost complete desiccation of the Dead Sea during the earlier of these lake level low stands based on a recovered gravel layer. Based on new petrographic analyses, we propose that, although it was a low stand, this well-sorted gravel layer may be a vestige of a thick turbidite that has been washed out during drilling rather than an in situ beach deposit. Two intervals of higher lake stands at ∼108-93±6 and ∼87-75±7 ka correspond to interstadial conditions in the central Mediterranean, i.e. pollen zones St. Germain I and II in Monticchio, and Greenland interstadials (GI) 24C23 and 21 in Greenland, as well as to sapropels S4 and S3 in the Mediterranean Sea. These apparent correlations suggest a close link of the climate in the Levant to North Atlantic and Mediterranean climates during the time of the build-up of Northern Hemisphere ice shields in the early last glacial period. © 2016 Author(s). 2016 English 18149324 10.5194/cp-12-75-2016 Climate of the Past 12 Copernicus GmbH 75-90 GFZ German Research Centre for Geosciences, Section 5.2, Climate Dynamics and Landscape Evolution, Telegrafenberg, Potsdam, 14473, Germany; University of Haifa, Department of Marine Geosciences, Leon H. Charney School of Marine Sciences, Mount Carmel, 31905, Israel; GFZ German Research Centre for Geosciences, Section 3.1, Inorganic and Isotope Geochemistry, Telegrafenberg, Potsdam, 14473, Germany; Hebrew University of Jerusalem, Fredy and Nadine Herrmann Institute of Earth Sciences, Givat Ram, Jerusalem, 91904, Israel; University of Potsdam, Institute of Earth and Environmental Science, Karl-Liebknecht-Str. 24-25, Potsdam-Golm, 14476, Germany 1 climate variation; core analysis; deep-sea sediment; interstadial; lake level; Last Glacial; last glaciation; Last Interglacial; marine isotope stage; marl; microfacies; Northern Hemisphere; petrography; sapropel; turbidite, Arctic; Atlantic Ocean; Atlantic Ocean (North); Dead Sea; Greenland; Levant; Mediterranean Region; Mediterranean Sea https://www.scopus.com/inward/record.uri?eid=2-s2.0-84956618731&doi=10.5194%2fcp-12-75-2016&partnerID=40&md5=e2b72dac578603b39d78e6de9e2c1d99 cited By 28 I. Neugebauer M.J. Schwab N.D. Waldmann R. Tjallingii U. Frank E. Hadzhiivanova R. Naumann N. Taha A. Agnon Y. Enzel A. Brauer article Wang201637 The Cretaceous continental sedimentary records are essential to our understanding of how the terrestrial geologic and ecologic systems responded to past climate fluctuations under greenhouse conditions and our ability to forecast climate change in the future. The Songliao Basin of Northeast China preserves a near-complete, predominantly lacustrine, Cretaceous succession, with sedimentary cyclicity that has been tied to Milankocitch forcing of the climate. Over 900 meters of drill-core recovered from the Upper Cretaceous (Turonian to Campanian) of the Songliao Basin has provided a unique opportunity for detailed analyses of its depositional and paleoenvironmental records through integrated and high-resolution cyclostratigraphic, magnetostratigraphic and geochronologic investigations.Here we report high-precision U-Pb zircon dates (CA-ID-TIMS method) from four interbedded bentonites from the drill-core that offer substantial improvements in accuracy, and a ten-fold enhancement in precision, compared to the previous U-Pb SIMS geochronology, and allow a critical evaluation of the Songliao astrochronological time scale. The results indicate appreciable deviations of the astrochronologic model from the absolute radioisotope geochronology, which more likely reflect cyclostratigraphic tuning inaccuracies and omitted cycles due to depositional hiatuses, rather than suspected limitations of astronomical models applied to distant geologic time.Age interpolation based on our new high-resolution geochronologic framework and the calibrated cyclostratigraphy places the end of the Cretaceous Normal Superchon (C34n-C33r chron boundary) in the Songliao Basin at 83.07. ±. 0.15 Ma. This date also serves as a new and improved estimate for the global Santonian-Campanian stage boundary. © 2016 Elsevier B.V. 2016 English 0012821X 10.1016/j.epsl.2016.04.007 Earth and Planetary Science Letters 446 Elsevier B.V. 37-44 State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing, 100083, China; School of the Earth Sciences and Resources, China University of Geosciences, Beijing, 100083, China; Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, United States; School of Ocean Sciences, China University of Geosciences, Beijing, 100083, China; Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, 100029, China Climate change; Core drilling; Deposition; Drills; Geologic models; Geomagnetism; Sedimentology; Silicate minerals, China; Cyclostratigraphy; Magnetostratigraphy; Santonian-Campanian boundary; Songliao basin; U-Pb geochronology, Geochronology, Cretaceous; cyclostratigraphy; geochronology; magnetic reversal; magnetostratigraphy; uranium-lead dating, China; Songliao Basin https://www.scopus.com/inward/record.uri?eid=2-s2.0-84964910279&doi=10.1016%2fj.epsl.2016.04.007&partnerID=40&md5=1ace3e1713c50237fba12fe1fdde7f23 cited By 65 T. Wang J. Ramezani C. Wang H. Wu H. He S.A. Bowring article Zhang2016112 A large body of evidence suggests that there were extensive coastal mountains along the East Asian margin during the Late Cretaceous. However, current knowledge of the paleo-mountains — the period, range, and elevation — is limited. Therefore, direct paleoaltimetry is needed to validate and evaluate the paleo-mountains in East Asia. Our study area is Jiaolai Basin, which is located at the East Asian continental margin. We estimate the paleoelevation of Jiaolai Basin during the Late Cretaceous using carbonate clumped isotope paleothermometry. After correcting for seasonal preference, latitudinal difference, and secular climate change, we conclude that the paleoelevation of Jiaolai Basin was almost certainly ≥2.0 km at ∼80 Ma. Combined with the evidence from stratigraphy, paleogeography, and paleoclimatology, our results suggest that the existence of coastal mountains along East Asia during the Late Cretaceous is likely and the model of Okhotomorsk–East Asia collision is preferred. © 2016 Elsevier B.V. 2016 English 0012821X 10.1016/j.epsl.2016.09.034 Earth and Planetary Science Letters 456 Elsevier B.V. 112-123 State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing, 100083, China; School of the Earth Science and Resources, China University of Geosciences, Beijing, 100083, China; The Key Laboratory of Marine Hydrocarbon Resources and Environment Geology, Qingdao Institute of Marine Geology, Qingdao, 266071, China Climate change; Isotopes; Stratigraphy, Clumped isotopes; coastal mountains; East Asia; Jiaolai Basin; Late cretaceous; Paleoelevation, Landforms, continental margin; Cretaceous; elevation; paleoclimate; paleogeography; stratigraphy, China; Jiaolai Basin; Shandong https://www.scopus.com/inward/record.uri?eid=2-s2.0-84994336862&doi=10.1016%2fj.epsl.2016.09.034&partnerID=40&md5=be6a73aa36b5e2a8ded22c8c4873391f cited By 66 L. Zhang C. Wang K. Cao Q. Wang J. Tan Y. Gao article Espinosa-Cardeña2016135 Along an east-west profile crossing the Chicxulub impact structure in northern Yucatán, México, Curie depths were obtained from statistical-spectral analysis of a grid of aeromagnetic data (256 km wide and 600 km long). These depths were corrected for flight height and depth to the sea floor to determine the geothermal gradient, assuming a temperature of 580 °C for the Curie temperature. Heat flow was then calculated from the geothermal gradients using a value of 2.67 W/m-for the mean crustal thermal conductivity. The results show a conspicuous heat flow high above on the impact basin. In this location, the heat flow is 80 mW/m2 approximately. Available offshore estimates of the depth to the crustal magnetic source bases, on the northern Yucatán platform, and onshore heat flow determination on 8 shallow bore holes, and in a 1511 m deep one, support the existence of this major high heat flow anomaly associated with the impact crater. This high heat flow might be related to the impact through: (1) an uplift of the crystalline basement rocks in the center of the crater; and (2) impact induced radioactive element concentration into the crust below the impact structure. Higher thermal conductivities at the lower crust might also play a key role. Available seismological and thermal property data are compatible with these mechanisms. © 2016 Elsevier B.V. 2016 10.1016/j.jvolgeores.2015.12.013 Journal of Volcanology and Geothermal Research 311 135-149 División de Ciencias de la Tierra, CICESE, Ensenada, Baja California, Mexico; Instituto de Geofísica, Universidad Nacional Autónoma de México, D.F. México, Mexico; University of Alberta, Canada https://www.scopus.com/inward/record.uri?eid=2-s2.0-84957916324&doi=10.1016%2fj.jvolgeores.2015.12.013&partnerID=40&md5=3882a548ca146c62b8dabc3b3f5c04ca cited By 4 J.M. Espinosa-Cardeña J.O. Campos-Enríquez M. Unsworth article Peng2016119 The morphology and ultrastructure of Gyrosigma peisonis var. major var. nov., a new variety of Gyrosigma peisonis found in Lake Qinghai (China), are described here on the basis of light and scanning electron microscopy. Most of the morphological features of this new variety are identical to those of the nominal variety Gyrosigma peisonis var. peisonis, but the variety major differs in its distinctly larger cell size and its higher value for the longitudinal/transverse stria density ratio, however. The seasonal variation of this taxon, which was investigated by a sediment-trap study is also discussed. © 2016 Magnolia Press. Article 2016 English 11793155 10.11646/phytotaxa.245.2.3 Phytotaxa 245 Magnolia Press 119 – 128 2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84957587454&doi=10.11646%2fphytotaxa.245.2.3&partnerID=40&md5=178a1df0b6fccc53588b1d1084bda1df Cited by: 7 Yumei Peng Patrick Rioual Zhangdong Jin Frithjof A. S. Sterrenburg conference Heinonen201626 The Kylylahti copper mine is located in the Outokumpu Cu-Co-Zn-Ni ore district in eastern Finland. We used high resolution reflection seismic profiles imaging the subsurface structures down to depth of 5 km and ZTEM (Z-axis Tipper Electromagnetic) inversion results revealing deep conductivity anomalies to study the deep exploration potential of the Kylylahti area. Regional interpretation of these deep penetrating data suggest that peridotite body of Kylylahti has substantial down plunge extend towards south and underneath the current mine. Additionally to regional interpretation, we have interpolated the densities measured in laboratory from drill-core samples to create a 3D-subsurface density distribution grid and compared it with the seismic reflection data. Overall correlation of reflectivity and density patterns is excellent: high density values correlate particularly well with high amplitude reflections while no prominent reflectivity is observed in the areas where density is uniformly low. The combination of reflectivity and interpolated density distribution suggest that the high density rock units possibly hosting the sulfide ore occur in a steeply dipping feature continuing northwest from the Kylylahti mine along the seismic profile. Results of this study highlight the deep exploration potential of the rock volumes below currently drilled depths in the Kylylahti area. Conference paper 2016 English 978-151082247-4 10.3997/2214-4609.201600032 EAGE/DGG Workshop on Deep Mineral Exploration 2016: Chasing Both Land and Sea Deposits European Association of Geoscientists and Engineers, EAGE 26 – 30 Cobalt alloys; Copper alloys; Copper mines; Core drilling; Deposits; Infill drilling; Potassium alloys; Reflection; Seismic waves; Seismology; Sulfur compounds; Zinc alloys; Conductivity anomalies; Density distributions; Exploration potential; High resolution reflection seismic; Inversion results; Seismic reflection data; Subsurface density; Subsurface structures; Mineral exploration https://www.scopus.com/inward/record.uri?eid=2-s2.0-84973897667&doi=10.3997%2f2214-4609.201600032&partnerID=40&md5=43cd6eb29c6ca9b25bf2e50b42c682c4 Cited by: 0 S. Heinonen A. Kontinen P. Sorjonen-Ward S. Aatos article Herzschuh2016 Broad-scale climate control of vegetation is widely assumed. Vegetation-climate lags are generally thought to have lasted no more than a few centuries. Here our palaeoecological study challenges this concept over glacial-interglacial timescales. Through multivariate analyses of pollen assemblages from Lake El'gygytgyn, Russian Far East and other data we show that interglacial vegetation during the Plio-Pleistocene transition mainly reflects conditions of the preceding glacial instead of contemporary interglacial climate. Vegetation-climate disequilibrium may persist for several millennia, related to the combined effects of permafrost persistence, distant glacial refugia and fire. In contrast, no effects from the preceding interglacial on glacial vegetation are detected. We propose that disequilibrium was stronger during the Plio-Pleistocene transition than during the Mid-Pliocene Warm Period when, in addition to climate, herbivory was important. By analogy to the past, we suggest today's widespread larch ecosystem on permafrost is not in climate equilibrium. Vegetation-based reconstructions of interglacial climates used to assess atmospheric CO 2-Temperature relationships may thus yield misleading simulations of past global climate sensitivity. 2016 English 20411723 10.1038/ncomms11967 Nature Communications 7 Nature Publishing Group Periglacial Research Section, Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Telegraphenberg A43, Potsdam, 14473, Germany; Institute of Earth and Environmental Sciences, Faculty of Sciences, University Potsdam, Potsdam-Golm, 14479, Germany; Department of Biology, University of Bergen, Postboks 7803, Bergen, 5020, Norway; Bjerknes Centre for Climate Research, Bergen, Norway; Environmental Change Research Centre, University College London, London, WC1E 6BT, United Kingdom; Institute of Geology and Mineralogy, Faculty of Mathematics and Natural Sciences, University of Cologne, Köln Cologne, 50674, Germany; Institute of Geology and Petroleum Technologies, Faculty of Natural Sciences, Kazan Federal University, Kazan, 420008, Russian Federation; Department of Geosciences, University of Massachusetts Amherst, Amherst, MA 01003-9297, United States atmospheric gas; climate change; detection method; disequilibrium; glacier dynamics; historical record; interglacial; paleoclimate; paleoecology; paleoenvironment; permafrost; Pliocene; Pliocene-Pleistocene boundary; reconstruction; vegetation dynamics, ecosystem; Far East; global climate; herbivory; interglacial; Larix; multivariate analysis; permafrost; Pleistocene; Pliocene; refugium; vegetation, Chukchi; Elgygytgyn Lake; Far East; Russian Far East; Russian Federation, Larix https://www.scopus.com/inward/record.uri?eid=2-s2.0-84976370863&doi=10.1038%2fncomms11967&partnerID=40&md5=a59dee9aaff646ffa2efd215156e9c6d cited By 53 U. Herzschuh H.J.B. Birks T. Laepple A. Andreev M. Melles J. Brigham-Grette article Just20162093 The bulk magnetic mineral record from Lake Ohrid, spanning the past 637 kyr, reflects large-scale shifts in hydrological conditions, and, superimposed, a strong signal of environmental conditions on glacial-interglacial and millennial timescales. A shift in the formation of early di-agenetic ferrimagnetic iron sulfides to siderites is observed around 320 ka. This change is probably associated with variable availability of sulfide in the pore water. We propose that sulfate concentrations were significantly higher before ∼ 320 ka, due to either a higher sulfate flux or lower dilution of lake sulfate due to a smaller water volume. Diagenetic iron minerals appear more abundant during glacials, which are generally characterized by higher Fe/Ca ratios in the sediments. While in the lower part of the core the ferrimagnetic sulfide signal overprints the primary detrital magnetic signal, the upper part of the core is dominated by variable proportions of high- to low-coercivity iron oxides. Glacial sediments are characterized by high concentration of high-coercivity magnetic minerals (hematite, goethite), which relate to enhanced erosion of soils that had formed during preceding interglacials. Superimposed on the glacial-interglacial behavior are millennial-scale oscillations in the magnetic mineral composition that parallel variations in summer insolation. Like the processes on glacial-interglacial timescales, low summer insolation and a retreat in vegetation resulted in enhanced erosion of soil material. Our study highlights that rock-magnetic studies, in concert with geochemical and sedimentological investigations, provide a multi-level contribution to environmental reconstructions, since the magnetic properties can mirror both environmental conditions on land and intra-lake processes. © Author(s) 2016. 2016 English 17264170 10.5194/bg-13-2093-2016 Biogeosciences 13 Copernicus GmbH 2093-2109 Institute of Geology and Mineralogy, University of Cologne, Cologne, Germany; Collaborative Research Centre, University of Cologne, 806 - Our Way to Europe, Cologne, Germany; Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences, Potsdam, Germany; Istituto Nazionale di Geofisica e Vulcanologia, Rome, Italy; Institute of Geological Sciences, Oeschger Centre for Climate Change Research, University of Bern, Bern, Switzerland; NERC Isotope Geosciences Facilities, British Geological Survey, Nottingham, United Kingdom 7 concentration (composition); dilution; environmental conditions; glacial deposit; iron oxide; iron sulfide; magnetic mineral; sediment chemistry; siderite; sulfate; timescale, Balkans; Lake Ohrid https://www.scopus.com/inward/record.uri?eid=2-s2.0-84964403161&doi=10.5194%2fbg-13-2093-2016&partnerID=40&md5=d6c6e42be918b3ef130c4d400422df17 cited By 18 J. Just N.R. Nowaczyk L. Sagnotti A. Francke H. Vogel J.H. Lacey B. Wagner article Vuillemin2016 Lake Towuti is a tectonic basin, surrounded by ultramafic rocks. Lateritic soils form through weathering and deliver abundant iron (oxy)hydroxides but very little sulfate to the lake and its sediment. To characterize the sediment biogeochemistry, we collected cores at three sites with increasing water depth and decreasing bottom water oxygen concentrations. Microbial cell densities were highest at the shallow site-a feature we attribute to the availability of labile organic matter (OM) and the higher abundance of electron acceptors due to oxic bottom water conditions. At the two other sites, OM degradation and reduction processes below the oxycline led to partial electron acceptor depletion. Genetic information preserved in the sediment as extracellular DNA (eDNA) provided information on aerobic and anaerobic heterotrophs related to Nitrospirae, Chloroflexi, and Thermoplasmatales. These taxa apparently played a significant role in the degradation of sinking OM. However, eDNA concentrations rapidly decreased with core depth. Despite very low sulfate concentrations, sulfate-reducing bacteria were present and viable in sediments at all three sites, as confirmed by measurement of potential sulfate reduction rates. Microbial community fingerprinting supported the presence of taxa related to Deltaproteobacteria and Firmicutes with demonstrated capacity for iron and sulfate reduction. Concomitantly, sequences of Ruminococcaceae, Clostridiales, and Methanomicrobiales indicated potential for fermentative hydrogen and methane production. Such first insights into ferruginous sediments showed that microbial populations perform successive metabolisms related to sulfur, iron, and methane. In theory, iron reduction could reoxidize reduced sulfur compounds and desorb OM from iron minerals to allow remineralization to methane. Overall, we found that biogeochemical processes in the sediments can be linked to redox differences in the bottom waters of the three sites, like oxidant concentrations and the supply of labile OM. At the scale of the lacustrine record, our geomicrobiological study should provide a means to link the extant subsurface biosphere to past environments. © 2016 Vuillemin, Friese, Alawi, Henny, Nomosatryo, Wagner, Crowe and Kallmeyer. Article 2016 English 1664302X 10.3389/fmicb.2016.01007 Frontiers in Microbiology 7 Frontiers Research Foundation JUN organic matter; organic nitrogen; oxidizing agent; anoxia; Article; atomic absorption spectrometry; biogeochemistry; biosphere; Chloroflexi; Clostridiales; controlled study; Deltaproteobacteria; denaturing gradient gel electrophoresis; Firmicutes; fluorescent lighting; gene sequence; ion chromatography; lake sediment; Methanomicrobiales; microbial community; Nitrospirae; nonhuman; nucleic acid analysis; oxidation reduction reaction; oxygen concentration; phylogeny; polymerase chain reaction; Ruminococcaceae; sulfate reducing bacterium; Thermoplasmatales; total organic carbon https://www.scopus.com/inward/record.uri?eid=2-s2.0-84980398286&doi=10.3389%2ffmicb.2016.01007&partnerID=40&md5=97c709482982702e15c9d16888a4b992 Cited by: 27; All Open Access, Gold Open Access, Green Open Access Aurèle Vuillemin André Friese Mashal Alawi Cynthia Henny Sulung Nomosatryo Dirk Wagner Sean A. Crowe Jens Kallmeyer article Cvetkoska20163147 We reconstruct the aquatic ecosystem interactions since the last interglacial period in the oldest, most diverse, hydrologically connected European lake system, by using palaeolimnological diatom and selected geochemistry data from Lake Ohrid "DEEP site" core and equivalent data from Lake Prespa core, Co1215. Driven by climate forcing, the lakes experienced two adaptive cycles during the last 92 ka: "interglacial and interstadial" and "glacial" cycle. The shortterm ecosystems reorganizations, e.g. regime shifts within these cycles substantially differ between the lakes, as evident from the inferred amplitudes of variation. The deeper Lake Ohrid shifted between ultra oligo- and oligotrophic regimes in contrast to the much shallower Lake Prespa, which shifted from a deeper, (oligo-) mesotrophic to a shallower, eutrophic lake and vice versa. Due to the high level of ecosystem stability (e.g. trophic state, lake level), Lake Ohrid appears relatively resistant to external forcing, such as climate and environmental change. Recovering in a relatively short time from major climate change, Lake Prespa is a resilient ecosystem. At the DEEP site, the decoupling between the lakes' response to climate change is marked in the prolonged and gradual changes during the MIS 5/4 and 2/1 transitions. These response differences and the lakes' different physical and chemical properties may limit the influence of Lake Prespa on Lake Ohrid. Regime shifts of Lake Ohrid due to potential hydrological change in Lake Prespa are not evident in the data presented here. Moreover, a complete collapse of the ecosystems functionality and loss of their diatom communities did not happen in either lake for the period presented in the study. © 2016 Author(s). 2016 English 17264170 10.5194/bg-13-3147-2016 Biogeosciences 13 Copernicus GmbH 3147-3162 Department of Physical Geography, Utrecht University, Palaeoecology, Utrecht, Netherlands; Department of Animal Ecology and Systematics, Justus Liebig University, Giessen, Germany; Institute of Geology and Mineralogy, University of Cologne, Cologne, Germany; Institute of Biology, University Ss Cyril and Methodius, Skopje, North Macedonia; Institute of Geological Sciences, Oeschger Centre for Climate Change Research, University of Bern, Bern, Switzerland 10 aquatic ecosystem; climate change; climate forcing; diatom; ecosystem resilience; fossil record; hydrological change; lacustrine environment; Last Interglacial; microbial community; micropaleontology; paleoclimate; paleoecology; paleolimnology; physicochemical property; reconstruction, Lake Mikri Prespa; Lake Ohrid, Bacillariophyta https://www.scopus.com/inward/record.uri?eid=2-s2.0-84973574852&doi=10.5194%2fbg-13-3147-2016&partnerID=40&md5=03ec85b8bd3ef3707333a02a44508b46 cited By 21 A. Cvetkoska E. Jovanovska A. Francke S. Tofilovska H. Vogel Z. Levkov T.H. Donders B. Wagner F. Wagner-Cremer article Wojewódka2016151 Cladocera species composition was analyzed in surface sediments of 29 lakes in Central America (Guatemala, El Salvador and Honduras). The material studied was collected with an Ekman grab in autumn 2013 from lakes located in lowland, highland and mountain regions. The study revealed high variability in qualitative and quantitative composition of subfossil Cladocera. A total of 31 Cladocera species (5 planktonic and 26 littoral) were identified, as well as 4 morphotypes that could not be identified (NRR 1-4). Planktonic Bosminidae and Daphniidae were the most abundant families. Daphniidae were restricted to water bodies in mountain regions, whereas Bosminidae were widely distributed in lakes with different abiotic conditions. Moreover, Bosminidae species also occurred in highly mineralized waters (> 900 μS cm–1). The great majority of the identified Cladocera species belonged to the littoral family Chydoridae. Chydorus cf. sphaericus was the most common species (found in 20 lakes), which probably reflects its tolerance to a wide spectrum of habitat conditions. Cluster analysis discriminated 6 groups of Cladocera species with a high correlation level within groups (≥0.8), which showed different types of correlation with lake characteristics and environmental variables. Canonical correspondence analysis (CCA) showed that altitude and secondly water electrical conductivity were the most important drivers of Cladocera species composition in the region studied. Furthermore, CCA analysis indicated lowland lakes with low water transparency were also characterized by peculiar species assemblages. © 2016, Page Press Publications. All rights reserved. Article 2016 English 19475721 10.4081/aiol.2016.6266 Advances in Oceanography and Limnology 7 Page Press Publications 151 – 162 2 El Salvador [Central America]; Guatemala [Central America]; Honduras; Bosminidae; Chydoridae; Chydorus sphaericus; Cladocera; Daphniidae; cluster analysis; crustacean; fossil assemblage; lacustrine deposit; morphotype; paleoecology; paleontology; plankton https://www.scopus.com/inward/record.uri?eid=2-s2.0-85054003587&doi=10.4081%2faiol.2016.6266&partnerID=40&md5=dae9834831d490ac9200cb46b4c5f7a5 Cited by: 11; All Open Access, Gold Open Access, Green Open Access Marta Wojewódka Edyta Zawisza Sergio Cohuo Laura Macario-González Antje Schwalb Izabela Zawiska Liseth Pérez article Fowler20164772 Hydrothermal activity results in element exchanges between seawater and oceanic crust that contribute to many aspects of ocean chemistry; therefore, improving knowledge of the associated chemical processes is of global significance. Hydrothermally altered basaltic drill core samples from the seawater-recharged Reykjanes geothermal system in Iceland record elemental gains and losses similar to those observed in samples of hydrothermally altered oceanic crust. At Reykjanes, rocks originally emplaced on the seafloor were buried by continued volcanism and subsided to the current depths (>2250 m below surface). These rocks integrate temperature-dependent elemental gains and losses from multiple stages of hydrothermal alteration that correspond to chemical exchanges observed in rocks from different crustal levels of submarine hydrothermal systems. Specifically, these lithologies have gained U, Mg, Zn, and Pb and have lost K, Rb, Ba, Cu, and light rare earth elements (La through Eu). Alteration and elemental gains and losses in lithologies emplaced on the seafloor can only be explained by a complex multistage hydrothermal alteration history. Reykjanes dolerite intrusions record alteration similar to that reported for the sheeted dike section of several examples of oceanic crust. Specifically, Reykjanes dolerites have lost K, Rb, Ba, and Pb, and gained Cu. The Reykjanes drill core samples provide a unique analog for seawater-oceanic crust reactions actively occurring at high temperatures (275–345°C) beneath a seafloor hydrothermal system. © 2016. American Geophysical Union. All Rights Reserved. 2016 English 15252027 10.1002/2016GC006595 Geochemistry, Geophysics, Geosystems 17 Blackwell Publishing Ltd 4772-4801 Department of Earth and Planetary Sciences, University of California, Davis, CA, United States 11 Clay alteration; Core drilling; Core samples; Drills; Europium compounds; Geothermal fields; Hydraulic structures; Hydrochemistry; Lithology; Magnesium; Rubidium; Seawater; Uranium, Drill core; Hydrothermal alterations; ICDP; Oceanic crust; Reykjanes, Europium, emplacement; geothermal system; hydrothermal alteration; hydrothermal system; lithology; oceanic crust; recharge; seawater; temperature effect; volcanism, Iceland https://www.scopus.com/inward/record.uri?eid=2-s2.0-85005807547&doi=10.1002%2f2016GC006595&partnerID=40&md5=7eabe4a2313379daf7f70e4cae3804b0 cited By 9 A.P.G. Fowler R.A. Zierenberg article Ikari2016164 The central San Andreas Fault in California is known as a creeping fault, however recent studies have shown that it may be accumulating a slip deficit and thus its seismogenic potential should be seriously considered. We conducted laboratory friction experiments measuring time-dependent frictional strengthening (healing) on fault zone and wall rock samples recovered during drilling at the San Andreas Fault Observatory at Depth (SAFOD), located near the southern edge of the creeping section and in the direct vicinity of three repeating microearthquake clusters. We find that for hold times of up to 3000 s, frictional healing follows a log-linear dependence on hold time and that the healing rate is very low for a sample of the actively shearing fault core, consistent with previous results. However, considering longer hold times up to ∼350,000 s, the healing rate accelerates such that the data for all samples are better described by a power law relation. In general, samples having a higher content of phyllosilicate minerals exhibit low log-linear healing rates, and the notably clay-rich fault zone sample also exhibits strong power-law healing when longer hold times are included. Our data suggest that weak faults, such as the creeping section of the San Andreas Fault, can accumulate interseismic shear stress more rapidly than expected from previous friction data. Using the power-law dependence of frictional healing on hold time, calculations of recurrence interval and stress drop based on our data accurately match observations of discrete creep events and repeating Mw=2 earthquakes on the San Andreas Fault. © 2016 Elsevier B.V. 2016 English 0012821X 10.1016/j.epsl.2016.06.036 Earth and Planetary Science Letters 450 Elsevier B.V. 164-172 MARUM, Center for Marine Environmental Sciences, University of Bremen, Germany; Istituto Nazionale di Geofisica e Vulcanologia, Rome, Italy; School of Geology and Geophysics, University of Oklahoma, Norman, OK, United States; Central Laboratory for Crystallography and Applied Material Sciences, Crystallography Group, Geosciences, University of Bremen, Germany Clay minerals; Earthquakes; Friction; Rock drilling; Shear stress; Strike-slip faults; Tribology, Creeping faults; Friction experiments; Linear dependence; Power law relation; Power-law dependences; Recurrence intervals; SAFOD; San Andreas fault, Structural geology, drilling; earthquake recurrence; fault zone; friction; microearthquake; recurrence interval; San Andreas Fault, California; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-84976636936&doi=10.1016%2fj.epsl.2016.06.036&partnerID=40&md5=a29c20b66df0fa14fa2ab18d16fb0939 cited By 15 M.J. Ikari B.M. Carpenter A.J. Kopf article Dultz201671 For an understanding of the effect of solution composition on the dissolution rate of basaltic glass detailed knowledge of surface chemistry is important. Here the zeta potential (ζ) as a characteristic parameter of the magnitude of surface charge at the solid-liquid interface was used to determine ionic effects on surface chemistry in initial stages of basaltic glass dissolution. In a systematic approach powdered synthetic basaltic glass was dispersed in solutions of different cations (NO3- salts of Na+, K+, Mg2+, Ca2+, Ba2+, Zn2+, and Al3+) and anions (Na+ salts of F-, Cl-, I-, NO3-, SO42-, C2O42-, HPO42-), each in concentrations of 0.1, 0.5, 1.0, 2.5, and 5.0 mmol/L. ζ was traced in time sequences up to 12,000 h at ideally circumneutral pH. Ion affinities to glass surfaces were characterized by sorption isotherms. A change of glass chemical composition by the formation of altered layers was determined by depth profiling using secondary neutral mass spectrometry (SNMS). The dissolution of the glass was quantified by the amount of Si released after 4000 h.A marked decrease of ζ in deionized water within the first 3 h reaction time is assigned to the desorption of alkali and alkaline earth metal cations from the glass surface and formation of negatively charged SiO- sites. The addition of anions resulted in stronger negative initial ζ values in comparison with the experiment in deionized H2O indicating marked anion adsorption on surface sites, most obvious for F-, C2O42- and HPO42-. The initial ζ was increased upon the addition of divalent cations indicating neutralization of negatively charged surface sites. Over time a striking shift from negative to positive ζ was obtained, most markedly for Ca2+ and Zn2+. The addition of trivalent Al3+ resulted directly in positive ζ indicating a strong adsorption on glass surfaces. With the progress of the experiment the sign of ζ reversed to negative values again. The reason for charge reversal is not fully understood and might be related with cation adsorption exceeding the negative surface charge and a concentration of Fe oxides at the glass surface. After an ~2000 h reaction time ζ adjusted for most electrolyte additions to slightly negative ζ until the end of the experiment, indicating that a final state in the composition of surface sites was reached. The presence of monovalent Na+ and K+ in solution suppressed Si release from the glass, whereas it is accelerated by bivalent cations. It appears that the neutralization of deprotonated ≡Si-O- sites by monovalent cations - their preferential binding is also indicated by chemical analysis - favors polymerization resulting in slower Si release. Upon the addition of Al3+ it is likely that ≡Si-O-Al-O-Si≡ bonds are formed, which can suppress Si release. The presence of F-, C2O42-, and HPO42- clearly enhances glass dissolution, most probably by increasing the coordination of network forming cations, hereby weakening bonds. The observed generation of positive ζ on basaltic glass surfaces is remarkable, and can improve in natural systems the adsorption capability of the basaltic glass surface for negatively charged compounds from pore solution, anions, dissolved organic matter and also bacterial cell walls. © 2016 Elsevier B.V. 2016 English 00092541 10.1016/j.chemgeo.2016.01.027 Chemical Geology 426 Elsevier 71-84 Institute of Mineralogy, Leibniz Universität Hannover, Callinstr. 3, Hannover, D-30167, Germany; Institute of Non-Metallic Materials, Clausthal University of Technology, Zehntnerstraße 2a, Clausthal-Zellerfeld, D-38678, Germany Adsorption; Alkalinity; Aluminum; Basalt; Binding sites; Biological materials; Calcium; Cell membranes; Chemical analysis; Deionized water; Depth profiling; Dissolution; Electrolytes; Geochemistry; Ions; Mass spectrometry; Negative ions; Phase interfaces; Positive ions; Salts; Silicon; Surface chemistry; Zeta potential; Zinc, Alkaline Earth metal cations; Basaltic glass; Charge reversal; Dissolved organic matters; Electrolyte effect; Negative surface charges; Negatively charged surfaces; Secondary neutral mass spectrometry, Glass, concentration (composition); dissolution; electrolyte; experimental study; igneous geochemistry; silicon, Bacteria (microorganisms) https://www.scopus.com/inward/record.uri?eid=2-s2.0-84957899504&doi=10.1016%2fj.chemgeo.2016.01.027&partnerID=40&md5=aedb041748dc45d30eb524e65b457794 cited By 9 S. Dultz H. Behrens G. Helsch J. Deubener article Wojatschke20163865 The presence of smectite (saponite) in fault gouge from the Central Deforming Zone of the San Andreas Fault at Parkfield, CA has been linked to low mechanical strength and aseismic slip. However, the precise relationship between clay mineral structure, fabric development, fault strength, and the stability of frictional sliding is not well understood. We address these questions through the integration of laboratory friction tests and FIB-SEM analysis of fault rock recovered from the San Andreas Fault Observatory at Depth (SAFOD) borehole. Intact fault rock was compared with experimentally sheared fault gouge and different proportions of either quartz clasts or SAFOD clasts extracted from the sample. Nano-textural measurements show the development of localized clay particle alignment along shear folia developed within synthetic gouges; such slip planes have multiples of random distribution (MRD) values of 3.0–4.9. The MRD values measured are higher than previous estimates (MRD 1.5) that show lower degrees of shear localization and clay alignment averaged over larger volumes. The intact fault rock exhibits less well-developed nano-clay fabrics than the experimentally sheared materials, and MRD values decrease with smectite content. We show that the abundance, strength, and shape of clasts all influence fabric evolution via strain localization: quartz clasts yield more strongly developed clay fabrics than serpentine-dominated SAFOD clasts. Our results suggest that (1) both clay abundance and the development of nano-scale fabrics play a role in fault zone weakening and (2) aseismic creep is promoted by slip along clay shears with >20 wt % smectite content and MRD values ≥2.7. © 2016. American Geophysical Union. All Rights Reserved. 2016 English 15252027 10.1002/2016GC006500 Geochemistry, Geophysics, Geosystems 17 Blackwell Publishing Ltd 3865-3881 Institut of Geography and Geology, Ernst-Moritz-Arndt-University Greifswald, Greifswald, Germany; Dipartimento di Scienze della Terra, Università degli Studi La Sapienza, Rome, Italy; ConocoPhilips School of Geology and Geophysics, University of Oklahoma, Norman, OK, United States; Department of Geosciences and Center for Geomechanics, Geofluids and Geohazards, Pennsylvania State University, University Park, PA, United States 10 Clay minerals; Deformation; Friction; Nanotechnology; Quartz; Serpentine; Silicate minerals; Strike-slip faults; Structural geology; Tectonics, Different proportions; Fabric development; Fault zone; Frictional behavior; Frictional sliding; Random distribution; Shear localizations; Strain localizations, Fault slips, clay mineral; deformation; experimental study; fault gouge; fault zone; friction; petrofabric; San Andreas Fault; slip, California; Parkfield; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-84991051995&doi=10.1002%2f2016GC006500&partnerID=40&md5=6724f9bf452e160e5d118f74569e6ebc cited By 11 J. Wojatschke M.M. Scuderi L.N. Warr B.M. Carpenter D. Saffer C. Marone article Zou2016279 CCSD-SK-2 East Borehole is the main borehole of China Continental Scientific Drilling Project in Songliao Basin, which is designed to reach a depth of 6400 m to penetrate Cretaceous strata. Its implementation is important for the research of the Cretaceous sedimentary environment and climate, for the achievement of new breakthroughs in oil and gas exploration, for the enhancement of the deep-drilling level and geophysical logging techniques, etc. Based on the scientific objectives and tasks of this project, combined with the design of drilling engineering and the characteristics of well conditions, the authors carried out the logging design of CCSD-SK-2 East-Borehole,intending to adopt the most advanced equipment to acquire log data. The adopted logging suits include comprehensive logging in openhole and cement-evaluation logging in cased hole. Based on the situation of drilling times and programs, eight times of comprehensive logging and five times of cement-evaluation logging are designed respectively, and comprehensive logging suits in different drilling times are different; taking into account the challenge of high temperature under the depth of 4500 m, logging items are designed including both required and selected ones. This logging design not only seeks to completely acquire all kinds of log data, but also conduces to flexibly deal with complex conditions of the borehole, which would be beneficial to the achievement of scientific goals. © 2016, Editorial Office of Earth Science Frontiers. All right reserved. Article 2016 Chinese 10052321 10.13745/j.esf.2016.03.031 Earth Science Frontiers 23 Science Frontiers editorial department 279 – 287 3 Cements; Deep oil well drilling; Density measurement (specific gravity); Geophysics; Oil well drilling; Oil well drilling equipment; Petroleum prospecting; Well logging; Continental scientific drillings; Cretaceous; Drilling engineering; Geophysical logging; Oil and gas exploration; Scientific objectives; Sedimentary environment; Songliao basin; Boring https://www.scopus.com/inward/record.uri?eid=2-s2.0-84971281741&doi=10.13745%2fj.esf.2016.03.031&partnerID=40&md5=34c1bbd2f4b6eaefeee10ccbcb553a61 Cited by: 14 Changchun Zou Liang Xiao Yixiong Niu Jie Hou Cheng Peng article Leicher20162151 A tephrostratigraphic record covering the Marine Isotope Stages (MIS) 1-15 was established for the DEEP site record of Lake Ohrid (Macedonia and Albania). Major element analyses (energy dispersive spectroscopy (EDS) and wavelength-dispersive spectroscopy (WDS)) were carried out on juvenile fragments extracted from 12 tephra layers (OH-DP-0115 to OH-DP-2060). The geochemical analyses of the glass shards of all of these layers suggest an origin in the Italian volcanic provinces. They include the Y-3 (OH-DP-0115, 26.68-29.42 ka cal BP), the Campanian Ignimbrite-Y-5 (OH-DP-0169, 39.6±0.1 ka), and the X- 6 (OH-DP-0404, 109±2 ka) from the Campanian volcanoes, the P-11 of Pantelleria (OH-DP-0499, 133.5±2 ka), the Vico B (OH-DP-0617, 162±6 ka) from the Vico volcano, the Pozzolane Rosse (OH-DP-1817, 457±2 ka) and the Tufo di Bagni Albule (OH-DP-2060, 527±2 ka) from the Colli Albani volcanic district, and the Fall A (OH-DP- 2010, 496±3 ka) from the Sabatini volcanic field. Furthermore, a comparison of the Ohrid record with tephrostratigraphic records of mid-distal archives related to the Mediterranean area allowed the recognition of the equivalents of other less known tephra layers, such as the TM24a-POP2 (OH-DP-0404, 102±2 ka) recognized in the Lago Grande di Monticchio and the Sulmona Basin, the CF-V5-PRAD3225 (OH-DP-0624, ca. 163±22 ka) identified in the Campo Felice Basin and the Adriatic Sea, the SC5 (OH-DP-1955, 493.1±10.9 ka) recognized in the Mercure Basin, and the A11/12 (OH-DP-2017, 511±6 ka) sampled at the Acerno Basin, whose specific volcanic sources are still poorly constrained. Additionally, one cryptotephra (OH-DP-0027) was identified by correlation of the potassium X-ray flourescence (XRF) intensities from the DEEP site with those from a short core of a previous study from Lake Ohrid. In these cores, a maximum in potassium is caused by glass shards, which were correlated with the Mercato tephra (8.43-8.63 ka cal BP) from Somma-Vesuvius. The tephrostratigraphic work presented here allows, for the first time, the extension of a consistent part of the Middle Pleistocene tephrostratigraphy of Italian volcanoes as far as the Balkans. The establishment of the tephrostratigraphic framework for the Lake Ohrid record provides important, independent tie points for the age-depth model of the DEEP site sequence, which is a prerequisite for palaeoclimatic and palaeoenvironmental reconstructions. Furthermore, this age-depth model will help to improve and re-evaluate the chronology of other, both undated and dated tephra layers from other records. Thus, the Lake Ohrid record may potentially become the template for the central Mediterranean tephrostratigraphy, especially for the hitherto poorly known and explored lower Middle Pleistocene period. © 2016 Author(s). 2016 English 17264170 10.5194/bg-13-2151-2016 Biogeosciences 13 Copernicus GmbH 2151-2178 Institute of Geology and Mineralogy, University of Cologne, Zuelpicher Str. 49a, Cologne, Germany; Dipartimento di Scienze della Terra, University of Pisa, Via S. Maria 53, Pisa, Italy; Dipartimento di Scienze della Terra e Geoambientali, University of Bari, Via Orabona 4, Bari, Italy; Istituto per la Dinamica Dei Processi Ambientali (IDPA), CNR, Via M. Bianco 9, Milan, Italy; Istituto di Geologia Ambientale e Geoingegneria, CNR, Via Salaria km 29 300, Monterotondo, Rome, Italy; Laboratoire des Sciences du Climat et de l'Environnement, UMR 8212, CEA/CNRS/UVSQ, Université Paris-Saclay, Gif-sur-Yvette, France; Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Pisa, Via della Faggiola 32, Pisa, Italy 7 biostratigraphy; Campanian; geochemical method; marine environment; paleoclimate; paleoenvironment; Pleistocene; tephra; tephrochronology; volcanic soil, Abruzzi; Adriatic Sea; Alban Hills; Albania; Apennines; Balkans; Basilicata; Campania [Italy]; Italy; L'Aquila; Lago Grande di Monticchio; Lake Ohrid; Lazio; Macedonia [Southern Europe]; Mediterranean Sea; Mount Somma; Napoli [Campania]; Potenza; Sulmona Basin; Vesuvius; Vico https://www.scopus.com/inward/record.uri?eid=2-s2.0-84964407338&doi=10.5194%2fbg-13-2151-2016&partnerID=40&md5=48e37f6d4e8e8a692983dccb824e9df2 cited By 61 N. Leicher G. Zanchetta R. Sulpizio B. Giaccio B. Wagner S. Nomade A. Francke P. Del Carlo article doughty_flowing_2016 Flowing fluid electrical conductivity (FFEC) logging is a hydrogeologic testing method that is usually conducted in an existing borehole. However, for the 2,500-m deep COSC-1 borehole, drilled at Åre, central Sweden, it was done within the drilling period during a scheduled 1-day break, thus having a negligible impact on the drilling schedule, yet providing important information on depths of hydraulically conductive zones and their transmissivities and salinities. This paper presents a reanalysis of this set of data together with a new FFEC logging data set obtained soon after drilling was completed, also over a period of 1 day, but with a different pumping rate and water-level drawdown. Their joint analysis not only results in better estimates of transmissivity and salinity in the conducting fractures intercepted by the borehole, but also yields the hydraulic head values of these fractures, an important piece of information for the understanding of hydraulic structure of the subsurface. Two additional FFEC logging tests were done about 1 year later, and are used to confirm and refine this analysis. Results show that from 250 to 2,000 m depths, there are seven distinct hydraulically conductive zones with different hydraulic heads and low transmissivity values. For the final test, conducted with a much smaller water-level drawdown, inflow ceased from some of the conductive zones, confirming that their hydraulic heads are below the hydraulic head measured in the wellbore under non-pumped conditions. The challenges accompanying 1-day FFEC logging are summarized, along with lessons learned in addressing them. 2016 nov en 1431-2174, 1435-0157 10.1007/s10040-016-1497-5 Hydrogeology Journal 1--17 http://link.springer.com/article/10.1007/s10040-016-1497-5 Christine Doughty Chin-Fu Tsang Jan-Erik Rosberg Christopher Juhlin Patrick F. Dobson Jens T. Birkholzer article Zhou2016279 We report here on a previously unpublished sediment core from Qinghai Lake, China, that preserves a continuous record of sedimentation for the past 40 ka. A striking feature of the record is a set of distinct meltwater events recorded at 35, 19 and 14 ka respectively. These events are manifest as distinct pulses of relatively old organic radiocarbon in the sediments. We interpret these as a signal of glacial melting in the Qinghai Lake watershed. The meltwater signals are closely correlated to temperature and precipitation records associated with deglaciation. The events at 19 ka and 14 ka correspond to well-established high latitude Melt Water Pulse (MWP) events during Marine Isotope Stage (MIS) 2, and the 35 ka event corresponds to a period of pervasive high lake levels in western China during late MIS 3. We interpret these anomalous dates as the result of relatively old carbon that was destabilized by the glaciers, and released into the lake as the glaciers melted. The data indicate that this process takes thousands of years. We expect that the approach employed here to identify these events is generally applicable to any lake system with a significant glacial meltwater component. © 2016 Elsevier Ltd Article 2016 English 02773791 10.1016/j.quascirev.2016.08.005 Quaternary Science Reviews 149 Elsevier Ltd 279 – 287 China; Qinghai; Qinghai Lake; Carbon; Glacial geology; Organic carbon; Carbon effects; Lacustrine record; Meltwater event; Radiocarbon dating; Total Organic Carbon; core analysis; deglaciation; lacustrine environment; marine isotope stage; meltwater; precipitation assessment; radiocarbon dating; sedimentation; total organic carbon; watershed; Lakes https://www.scopus.com/inward/record.uri?eid=2-s2.0-84981303285&doi=10.1016%2fj.quascirev.2016.08.005&partnerID=40&md5=f2586f125fd5e33150387a10864d0989 Cited by: 34 Weijian Zhou Taibei Liu Hao Wang ZhiSheng An Peng Cheng Yizhi Zhu G.S. Burr inproceedings fischer2016fe 2016 Papers and Proceedings of the Royal Society of Tasmania 150 15--22 1 LA Fischer Q Yuan article Heeschen20166210 Gas hydrate production is still in the test phase. It is only now that numerical models are being developed to describe data and production scenarios. Laboratory experiments are carried out to test the rationale of the conceptual models and deliver input data. Major experimental challenges include (I) the simulation of a natural three-phase system of sand-hydrate-liquid with known and high hydrate saturations and (II) the simulation of transport behavior as deduced from field data. The large-scale reservoir simulator (LARS; 210 L sample) at the GFZ has met these challenges and allowed for the first simulation of the gas production test from permafrost hydrates at the Mallik drill site (Canada) via multistage depressurization. At the starting position, hydrate saturation was as high as 90%, formed from dissolved methane only. Whereas gas hydrate dissociation determined the flow patterns in the early pressure stages, the importance of different transport behaviors increased at lower pressure stages and increasing water content. Gas flow patterns as observed in Mallik were recorded. While the conceptual model for the experimental data does agree with the model proposed for Mallik at moderate and low gas production, it is different at high gas production rates. © 2016 American Chemical Society. 2016 English 08870624 10.1021/acs.energyfuels.6b00297 Energy and Fuels 30 American Chemical Society 6210-6219 GFZ German Research Centre for Geosciences, Telegrafenberg, Potsdam, 14473, Germany 8 Flow of gases; Flow patterns; Gases; Hydration; Methane, Gas production test; Gas-hydrate production; Hydrate dissociation; Laboratory experiments; Laboratory simulation; Reservoir simulator; Three phase system; Transport behavior, Gas hydrates https://www.scopus.com/inward/record.uri?eid=2-s2.0-84983670449&doi=10.1021%2facs.energyfuels.6b00297&partnerID=40&md5=a224d8f5a496b788fbbdbb44e22935d2 cited By 73 K.U. Heeschen S. Abendroth M. Priegnitz E. Spangenberg J. Thaler J.M. Schicks article 10.1127/ejm/2015/0027-2423 {The effect of the normative anorthite content on the position of cotectic curves in the Qz–Ab–Or–An system has been investigated at 200 MPa and a water activity of 0.5. To simulate compositions as close as possible to those of natural high-silica rhyolites, all investigated compositions also contained ~ 1 wt\% FeO and 0.2 wt\% TiO2. The position of the cotectic curves was deduced from crystallization experiments carried out between 790 and 850°C and using fourteen starting glass compositions containing ~ 3 wt\% H2O. The liquidus phase of the different starting materials was used to constrain the primary fields of quartz, plagioclase and sanidine. The compositions of residual melts coexisting with solid phases were used to define the position of cotectic curves. Compared to the haplogranite system, the eutectic point is shifted away from the Ab apex, and its composition is estimated to be Qz42Ab21Or37 when projected onto the haplogranite system. The implications for the estimation of the depth of magma storage conditions are discussed on the basis of an example from the Snake River Plain high-silica rhyolites.} 2015 03 0935-1221 10.1127/ejm/2015/0027-2423 European Journal of Mineralogy 27 147-159 2 https://doi.org/10.1127/ejm/2015/0027-2423 Sören Wilke Carolin Klahn Torsten Bolte Renat Almeev François Holtz article Jeppson20154983 The San Andreas Fault (SAF), like other mature brittle faults, exhibits a zone of low seismic velocity hypothesized to result from fluid pressure effects and/or development of a damage zone. To address the relative contributions of these mechanisms in developing low-velocity zones, we measured P and S wave velocities ultrasonically at elevated confining and pore pressures on core samples from the San Andreas Fault Observatory at Depth (SAFOD). We compared those data to wireline and seismic-scale velocities to examine the scale dependence of acoustic properties of the fault core and damage zone. Average laboratory P and S wave velocities of the fault gouge at estimated in situ conditions are 3.1 and 1.5 km/s, respectively, consistent with the sonic log from the same intervals. These data show that fault core has intrinsically low velocity, even if no anomalous pore pressure is assumed, due to alteration and mechanical damage. In contrast, laboratory average P and S wave velocities for the damage zone are 4.7 and 2.5 km/s, up to 41% greater than the sonic log in the damage zone. This scale dependence indicates that stress conditions or macroscale features dominate the damage zone's acoustic properties, although velocity dispersion could play a role. Because no pressure anomaly was detected while drilling the SAFOD borehole, we infer that damage at a scale larger than core samples controls the elastic properties of the broader damage zone. This result bolsters other independent lines of evidence that the SAF does not contain major pore fluid overpressure at SAFOD. ©2015. American Geophysical Union. All Rights Reserved. 2015 English 21699313 10.1002/2015JB012043 Journal of Geophysical Research: Solid Earth 120 Blackwell Publishing Ltd 4983-4997 Geoscience Department, University of Wisconsin-Madison, Madison, WI, United States 7 acoustic property; elastic modulus; fault zone; laboratory method; P-wave; S-wave; San Andreas Fault; seismic velocity; ultrasonics; velocity structure; wave velocity https://www.scopus.com/inward/record.uri?eid=2-s2.0-84939250077&doi=10.1002%2f2015JB012043&partnerID=40&md5=f22ddf32214342ab99ac44251dc4baab cited By 19 T.N. Jeppson H.J. Tobin article Lisé-Pronovost201572 The sedimentary archive from Laguna Potrok Aike is the only continuous record reaching back to the last Glacial period in continental southeastern Patagonia. Located in the path of the Southern Hemisphere westerly winds and in the source region of dust deposited in Antarctica during Glacial periods, southern Patagonia is a vantage point to reconstruct past changes in aeolian activity. Here we use high-resolution rock-magnetic and physical grain size data from site 2 of the International Continental scientific Drilling Program (ICDP) Potrok Aike maar lake Sediment Archive Drilling prOject (PASADO) in order to develop magnetic proxies of dust and wind intensity at 52°S since 51,200 cal BP. Rock-magnetic analysis indicates the magnetic mineral assemblage is dominated by detrital magnetite. Based on the estimated flux of magnetite to the lake and comparison with distal dust records from the Southern Ocean and Antarctica, kLF is interpreted as a dust indicator in the dust source of southern Patagonia at the millennial time scale, when ferrimagnetic grain size and coercivity influence are minimal. Comparison to physical grain-size data indicates that the median destructive field of isothermal remanent magnetization (MDFIRM) mostly reflects medium to coarse magnetite bearing silts typically transported by winds for short-term suspension. Comparison with wind-intensity proxies from the Southern Hemisphere during the last Glacial period and with regional records from Patagonia since the last deglaciation including marine, lacustrine and peat bog sediments as well as speleothems reveals similar variability with MDFIRM up to the centennial time scale. MDFIRM is interpreted as a wind-intensity proxy independent of moisture changes for southeastern Patagonia, with stronger winds capable of transporting coarser magnetite bearing silts to the lake. © 2014 Elsevier B.V. Article 2015 10.1016/j.epsl.2014.11.007 Earth and Planetary Science Letters 411 72 – 86 Argentina; Laguna Potrok Aike; Santa Cruz [Argentina]; Dust; Glacial geology; Grain size and shape; Infill drilling; Lakes; Lithology; Magnetism; Magnetite; Minerals; Rocks; Salinity measurement; Silt; Wind; Lake sediments; PASADO; Rock magnetism; Westerly winds; Wind intensity; dust; grain size; lacustrine deposit; Last Glacial; magnetic property; magnetite; remanent magnetization; rock property; Southern Hemisphere; westerly; wind field; Sediments https://www.scopus.com/inward/record.uri?eid=2-s2.0-84918839701&doi=10.1016%2fj.epsl.2014.11.007&partnerID=40&md5=614e44a37d57463b7df4f18aceec2056 Cited by: 15 Agathe Lisé-Pronovost Guillaume St-Onge Claudia Gogorza Torsten Haberzettl Guillaume Jouve Christian Ohlendorf Catalina Gebhardt Bernd Zolitschka article Hu2015 Many large paleo-lakes in North China were formed after the Triassic Era. Seawater incursion events (SWIEs) in these lakes have been extensively discussed in the literature, yet lack reliable methodology and solid evidence, which are essential for reconstructing and confirming SWIEs. The present study employs specific marine biological markers (24-n-propyl and 24-isopropyl cholestanes) to trace SWIEs in a dated core taken from the Songliao Basin (SLB). Two SWIEs were identified. The first SWIE from 91.37 to 89.00 Ma, was continuous and variable but not strong, while the second SWIE from 84.72 to 83.72 Ma was episodic and strong. SWIEs caused high total organic carbon (TOC) and negative δ13Corg values in the sediments, which were interpreted as an indication of high productivity in the lake, due to the enhancement of nutrient supplies as well as high levels of aqueous CO2, due to the mixing of alkaline seawater and acidic lake water. The SWIEs in SLB were controlled by regional tectonic activity and eustatic variation. Movement direction changes of the Izanagi/Kula Plate in 90 Ma and 84 Ma created faults and triggered SWIEs. A high sea level, from 90 to 84 Ma, also facilitated the occurrence of SWIEs in SLB. 2015 English 20452322 10.1038/srep09508 Scientific Reports 5 Nature Publishing Group State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, 510640, China; State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing, 100083, China biological marker; carbon; sea water, China; lake, Biomarkers; Carbon; China; Lakes; Seawater https://www.scopus.com/inward/record.uri?eid=2-s2.0-84929193257&doi=10.1038%2fsrep09508&partnerID=40&md5=944740a309163009ed803165e3f81163 cited By 51 J.F. Hu P.A. Peng M.Y. Liu D.P. Xi J.Z. Song X.Q. Wan C.S. Wang article Delgadillo-Peralta2015145 Results of a paleomagnetic and magnetic fabrics study of the basal suevitic breccias in the Chicxulub impact crater, Yucatán platform, Gulf of Mexico are presented. The breccias were cored in the Yaxcopoil-1 borehole, which is located at about 62 km radial distance from the crater center. The impactite sequence in the Yaxcopoil-1 borehole is ~100 m thick and formed by six subunits with distinct petrographic and geochemical characteristics. Here we investigate the basal subunit interpreted as: a ground surge in the transient cavity, a melt breccia with clastic material, or an excavation flow from the ejecta curtain interacting with the ejecta plume collapse. Characterization of the magnetic fabrics using rock magnetics and anisotropy of magnetic susceptibility (AMS) are used to investigate on the emplacement mechanism of the suevites. Magnetic hysteresis and k-T curves show that the magnetic mineralogy is dominated by low-Ti titanomagnetites and magnetite. The AMS fabrics record mixtures of oblate and prolate ellipsoids and principal susceptibility axial distributions with relatively high angular scatter, related to turbulent high temperature conditions during ejecta emplacement. Magnetic fabric parameters and principal susceptibility axial distributions correlate with modal composition, relative contents and orientation of melt particles. Results are interpreted in terms of an emplacement mode as an early excavation flow that incorporated ground surge components. 2015 Revista Mexicana de Ciencias Geologicas 32 145-155 Laboratorio de Paleomagnetismo y Paleoambientes, Instituto de Geofísica, Universidad Nacional Autónoma de México, Coyoacán México D.F., 04510, Mexico 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84930145698&partnerID=40&md5=ef25a10ddea591278abef6f363f4c831 cited By 3 M. Delgadillo-Peralta J. Urrutia-Fucugauchi L. Pérez-Cruz M. Velasco-Villarreal conference Koeberl2015310 The first 2.5 billion years of the terrestrial impact history are not documented by any impact structures. Only a few spherule layers of impact origin are known, most of them of late Archean to early Proterozoic age. In the Barberton Greenstone Belt (South Africa), several spherule horizons (layers S1 to S4, possibly up to S8, with ages between ∼3.5 and ∼3.2 Ga) are amongst the oldest deposits from large bolide impacts onto Earth. Impact evidence is limited to (highly) elevated siderophile element contents and Cr isotopic compositions. Other isotope tools, such as the 187Re-188Os radionuclide system in combination with high-precision concentration data for siderophile elements, might be useful to confirm the propositions regarding the presence of meteoritic components made so far. Two recently recovered drill cores from the central and northern Barberton area (CT3 and BARB5) with as many as 18 spherule layer intersections of Paleoarchean age (some of which may be due to tectonic duplication, some might correlate with the S2 to S4 layers) provide an outstanding opportunity to gain new insight into the early impact bombardment of Earth. We present new mineralogical, chemical, and 187Re-188Os isotope data on CT3 and BARB5 drill core samples. Spherules in most layers exhibit undeformed shapes and include vesicles. Sulfides frequently are present in both matrix and spherules. Osmium data reveal a trend between the spherule-free horizons (intercalating the spherule layers) and spherule-matrix aggregates. Whereas the former typically exhibit elevated 187Os/188Os ratios of up to ∼1.2 and low Os and Ir concentrations below several hundred ppt, spherule-matrix aggregates tend to be less radiogenic (down to subchondritic present day 187Os/188Os ratios) with Os and Ir concentrations as high as in chondrites. Chromium-Ir correlations for CT3 and BARB5 samples mirror earlier results on S1 to S4 layers and can be interpreted in favor of an impact origin of the here investigated spherule horizons. © 2015 The Authors. Conference paper 2015 English 18777058 10.1016/j.proeng.2015.04.052 Procedia Engineering 103 Elsevier Ltd Schonberg W.P. 310 – 317 Aggregates; Core drilling; Deposits; Drills; Iridium; Isotopes; Meteorites; Osmium; Archean; Greenstone belts; Highly siderophile elements; Osmium isotopes; spherules; Matrix algebra https://www.scopus.com/inward/record.uri?eid=2-s2.0-84991328147&doi=10.1016%2fj.proeng.2015.04.052&partnerID=40&md5=29574d04e0062b2c880d6de4140b0cfb Cited by: 11; All Open Access, Bronze Open Access Christian Koeberl Toni Schulz W. Uwe Reimold article Rajala201517 Microorganisms in the deep biosphere are believed to conduct little metabolic activity due to low nutrient availability in these environments. However, destructive penetration to long-isolated bedrock environments during construction of underground waste repositories can lead to increased nutrient availability and potentially affect the long-term stability of the repository systems, Here, we studied how microorganisms present in fracture fluid from a depth of 500 m in Outokumpu, Finland, respond to simple carbon compounds (C-1 compounds) in the presence or absence of sulphate as an electron acceptor. C-1 compounds such as methane and methanol are important intermediates in the deep subsurface carbon cycle, and electron acceptors such as sulphate are critical components of oxidation processes. Fracture fluid samples were incubated in vitro with either methane or methanol in the presence or absence of sulphate as an electron acceptor. Metabolic response was measured by staining the microbial cells with fluorescent dyes that indicate metabolic activity and transcriptional response with RT-qPCR. Our results show that deep subsurface microbes exist in dormant states but rapidly reactivate their transcription and respiration systems in the presence of C-1 substrates, particularly methane. Microbial activity was further enhanced by the addition of sulphate as an electron acceptor. Sulphate-and nitrate-reducing microbes were particularly responsive to the addition of C-1 compounds and sulphate. These taxa are common in deep biosphere environments and may be affected by conditions disturbed by bedrock intrusion, as from drilling and excavation for long-term storage of hazardous waste. © 2015 by the authors; licensee MDPI, Basel, Switzerland. Article 2015 English 20762607 10.3390/microorganisms3010017 Microorganisms 3 MDPI AG 17 – 33 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84937149116&doi=10.3390%2fmicroorganisms3010017&partnerID=40&md5=f3f50844f63d003e2e063a46d3fee4b3 Cited by: 30; All Open Access, Gold Open Access, Green Open Access Pauliina Rajala Malin Bomberg Riikka Kietäväinen Ilmo Kukkonen Lasse Ahonen Mari Nyyssönen Merja Itävaara article Lindhorst201584 Lake Ohrid, located on the Balkan Peninsula within the Dinaride-Albanide-Hellenide mountain belt, is a tectonically active graben within the South Balkan Extensional Regime (SBER). Interpretation of multichannel seismic cross sections and bathymetric data reveals that Lake Ohrid formed during two main phases of deformation: (1) a transtensional phase which opened a pull-apart basin, and (2) an extensional phase which led to the present geometry of Lake Ohrid. After the initial opening, a symmetrical graben formed during the Late Miocene, bounded by major normal faults on each side in a pull-apart type basin. The early-stage geometry of the basin has a typical rhomboidal shape restricted by two sets of major normal faults. Thick undisturbed sediments are present today at the site where the acoustic basement is deepest, illustrating that Lake Ohrid is a potential target for drilling a long and continuous sediment core for studying environmental changes within the Mediterranean region. Neotectonic activity since the Pliocene takes place along the roughly N-S-striking Eastern and Western Major Boundary Normal Faults that are partly exposed at the present lake floor. The tectono-sedimentary structure of the basin is divided into three main seismic units overlying the acoustic basement associated with fluvial deposits and lacustrine sediments. A seismic facies analysis reveals a prominent cyclic pattern of high- and low-amplitude reflectors. We correlate this facies cyclicity with vegetation changes within the surrounding area that are associated with glacial/interglacial cycles. A clear correlation is possible back to ca. 450 kyrs. Extrapolation of average sedimentation rates for the above mentioned period results in age estimate of ca. 2 Myrs for the oldest sediments in Lake Ohrid. © 2014 The Authors. Article 2015 English 0950091X 10.1111/bre.12063 Basin Research 27 84 – 101 1 Albania; Lake Ohrid; Macedonia [Southern Europe]; facies analysis; neotectonics; normal fault; sedimentary structure; sedimentation rate; tectonic evolution https://www.scopus.com/inward/record.uri?eid=2-s2.0-84920941884&doi=10.1111%2fbre.12063&partnerID=40&md5=dc61452043c893d62df12cb147f28e4d Cited by: 54 Katja Lindhorst S. Krastel K. Reicherter M. Stipp B. Wagner T. Schwenk article Cvetkoska2015215 Lake Prespa, in the Balkans, contains an important palaeo-archive in a key location for understanding Quaternary climate variability in the transition between Mediterranean and central European climate zones. Previous palaeoenvironmental research on sediment cores indicates that the lake is highly sensitive to climate change and that diatoms are likely to be strong palaeohydrological proxies. Here, we present new results from diatom analysis of a ca. 91 ka sequence, core Co1215, which spans the time from the end of the last interglacial to the present. Fluctuations in the diatom data were driven primarily by changes in lake level, as a function of shifts in moisture availability. Warmer interglacial (MIS 5, MIS 1) and interstadial (MIS 3) phases exhibit higher lake levels in spite of enhanced evaporative concentration, underlining the importance of changes in precipitation regimes over time. Low lake levels during glacial phases indicate extreme aridity, common to all Mediterranean lakes. Evidence for fluctuations in trophic status is linked, in part, to lake-level change, but also reflects nutrient enrichment from catchment processes. MIS 5a is characterized by the highest lake productivity in the sequence, but low lake levels, which are ascribed primarily to very low precipitation. On a suborbital timescale, the diatoms provide evidence for correlation to the millennial-scale variability recorded in the Greenland oxygen isotope records and clearly reflect the impact of the Heinrich H6, H5 and H3–1 ice-rafting events, suggesting the dominant influence of North Atlantic forcing in this region. Although the highest-amplitude shift in the diatom assemblages occurs during the time of H4 (40–38 ka), it may be superimposed upon the impact of the 39.28 cal ka BP Campanian Ignimbrite volcanic eruption. Diatoms from Lake Prespa core Co1215 display the first strong evidence for the impact of Italian volcanic activity on lacustrine biota in this region. Results emphasize the complexity of diatom response thresholds in different studies across the region. In the case of Lake Prespa, the results highlight the important role of precipitation for maintaining the hydrological balance of the lake, and indirectly, its biodiversity. © 2014, Springer Science+Business Media Dordrecht. 2015 English 09212728 10.1007/s10933-014-9821-3 Journal of Paleolimnology 53 Kluwer Academic Publishers 215-231 Institute of Biology, Ss Cyril and Methodius University, Arhimedova 3, Skopje, 1000, North Macedonia; Department of Geography, Environment and Earth Sciences, University of Hull, Hull, United Kingdom; Institute of Geology and Mineralogy, University of Cologne, Cologne, Germany; Seminar of Geography and Education, University of Cologne, Cologne, Germany; Centre for Environmental Geochemistry, School of Geography, University of Nottingham, Nottingham, United Kingdom; NERC Isotope Geosciences Facility, British Geological Survey, Nottingham, United Kingdom; Department of Geology, University of Leicester, Leicester, United Kingdom 2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84925542974&doi=10.1007%2fs10933-014-9821-3&partnerID=40&md5=7651b899872d1eea82d39bbca4a9c3a5 cited By 14 A. Cvetkoska Z. Levkov J.M. Reed B. Wagner K. Panagiotopoulos M.J. Leng J.H. Lacey article Ibarra2015781 Lake systems are important paleoclimate archives that preserve ecosystem and hydrologic responses to critical periods in Earth history, such as carbon cycle perturbations and glacial-interglacial cycles. Geochemical measurements of biogenic carbonate (for example, δ18O, δ13C, 87Sr/86Sr, [Li], [U], [Sr], and [Mg]) are indicators of hydrologic variability in lake systems throughout the geologic record. In this study, we present a new closed-basin lake modeling approach, HyBIM (the Hydrologic Balance Inverse Model) that employs a system of total differential equations and uses the measured δ18O, Sr/Ca, and Mg/Ca of biogenic carbonate to determine changes in temperature, runoff, and lake evaporation. Using equally-spaced time steps, these equations are simultaneously solved to constrain the hydrologic parameters of the lake as recorded in biogenic carbonate. We use a Monte Carlo approach to account for uncertainty in the input parameters, such as δ18O temperature relationships, partition coefficient uncertainty, and watershed solute chemistry. For illustrative purposes, we apply the model to two ostracod valve datasets covering different timescales: (1) the Cretaceous Songliao Basin, northeast China, and (2) Holocene Lake Miragoane, Haiti. Modern water measurements of water isotopes and cation concentrations from each location are required as model inputs. We compare our modeling results with author interpretations and geologic observations. The modeling approach presented in this study can be applied to other closed-basin lake records, can be modified for other calcifying species (for example, gastropods or mollusks) or with calibration to inorganic lacustrine carbonate. In addition, this approach holds promise for extension with additional proxy measurements (that is, δD, U/Ca or Li/Ca) and changing source area on tectonic timescales using proxies that reflect changing source lithology (that is, Sr and Pb isotopes). Future incorporation of age model uncertainty in the Monte Carlo approach will also provide utility by quantifying temporal uncertainty on the hydrologic response recorded by lake sediments. 2015 English 00029599 10.2475/09.2015.01 American Journal of Science 315 Yale University 781-808 Department of Earth System Science, Stanford University, 473 Via Ortega, Stanford, CA 94305-4216, United States 9 lacustrine deposit; lake water; oxygen isotope; paleoclimate; paleohydrology; trace element; water chemistry; water quality; water temperature, Gastropoda; Mollusca; Ostracoda https://www.scopus.com/inward/record.uri?eid=2-s2.0-84954305645&doi=10.2475%2f09.2015.01&partnerID=40&md5=35246d0d8754e4a869150b219d0abfcc cited By 9 D.E. Ibarra C.P. Chamberlain article Lin2025 Article 2015 Chinese Journal of Nature 37 79-85 02 Y. Huang C. Wang article Ariztegui20151655 Review 2015 10.1007/s00531-015-1148-4 International Journal of Earth Sciences 104 1655 – 1665 6 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84940958158&doi=10.1007%2fs00531-015-1148-4&partnerID=40&md5=0af1c04e97299773cc0ebbf26995db8d Cited by: 22; All Open Access, Green Open Access, Hybrid Gold Open Access Daniel Ariztegui Camille Thomas Aurèle Vuillemin article Ariztegui20151655 Recently, the discovery of active microbial life in deep-sea sediments has triggered a rapid development of the field known as the “deep biosphere.” Geomicrobiological investigations in lacustrine basins have also shown a substantial microbial impact on lake sediments similar to that described for the marine record. Although only 30 % of the lake sites drilled by the International Continental Drilling Program (ICDP) have included microbial investigations, these lakes cover a relatively wide range of salinities (from 0.15 to 33.8 %), pH (from 6.0 to 9.8) and environmental conditions (from very arid to humid subtropical conditions). Here, we analyze results of very recent ICDP lake sites including subsurface biosphere research from southern Patagonia (Laguna Potrok Aike) to the Levantine area (Dead Sea) as well as the East Anatolian high plateau (Lake Van) and Macedonia (Lake Ohrid). These various settings allow the examination of the impact of contrasting environments on microbial activity and their subsequent role during early diagenesis. Furthermore, they permit the identification of biosignatures of former microbial activity recorded in the sediments as well as investigating the impact of microbes in biogeochemical cycles. One of the general outcomes of these preliminary investigations is data to support the hypothesis that microbes react to climatically driven environmental changes that have a direct impact on their subsurface distribution and diversity. This is clear at conspicuous levels associated with well-known climatic periods such as the Medieval Climatic Anomaly or the Little Ice Age. Although more research is needed, this relationship between prevailing microbial assemblages and different climatic settings appears to dominate the lacustrine sites studied until to date. © 2015, The Author(s). 2015 English 14373254 10.1007/s00531-015-1148-4 International Journal of Earth Sciences 104 Springer Verlag 1655-1665 Department of Earth Sciences, University of Geneva, rue des Maraichers 13, Geneva, 1205, Switzerland; Section 4.5 Geomicrobiology, Helmholtz Centre Potsdam, GFZ German Research for Geosciences, Potsdam, 14473, Germany 6 biosphere; deep-sea sediment; diagenesis; drilling; environmental change; genomics; geological record; geomicrobiology; lacustrine deposit; microbial activity; paleoclimate; sedimentary basin, Argentina; Dead Sea; Laguna Potrok Aike; Lake Ohrid; Lake Van; Levantine Sea; Mediterranean Sea; Patagonia; Santa Cruz [Argentina]; Turkey https://www.scopus.com/inward/record.uri?eid=2-s2.0-84940958158&doi=10.1007%2fs00531-015-1148-4&partnerID=40&md5=0af1c04e97299773cc0ebbf26995db8d cited By 18 D. Ariztegui C. Thomas A. Vuillemin article Zhou2015399 There is ongoing debate over how the water level and composition of the water in Lake Qinghai changed in the past and might change in future. This study of the microchemistry of otoliths from ancient naked carp explores the chemistry of a relict lake isolated from Lake Qinghai during the Little Ice Age (LIA). A close correlation between the ages measured on fish bone and otoliths by AMS-14C, and by optically stimulated luminescence on overlying sediments, confirms a high water level in Lake Qinghai before 680-300years ago. The contrasting compositions of the ancient otoliths relative to modern otoliths and waters indicate that the relict lake became enriched in 18O, Mg, Li, B and to a lesser extent Ba, but depleted in 13C, owing to strong evaporation, authigenic carbonates precipitation, (micro-)organism activity, and less fresh water input after it was isolated. If there were long-term fresh water input, however, a reverse trend might occur. The most important observation is that, because the waters have been supersaturated with respect to carbonates, authigenic carbonate precipitation would result in low but consistent Sr/Ca ratios in the lakes, as recorded by both the ancient and modern otoliths. The geochemical records of ancient versus modern biogenic carbonates provide insights into the long-term hydroclimatic evolution processes of an inland water body. © 2015 Elsevier Ltd. Article 2015 English 13679120 10.1016/j.jseaes.2015.02.006 Journal of Asian Earth Sciences 105 Elsevier Ltd 399 – 407 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84930962877&doi=10.1016%2fj.jseaes.2015.02.006&partnerID=40&md5=2b7da426d3250a2e696b1f7c2271adcd Cited by: 1 Ling Zhou Zhangdong Jin Chia-Hui Wang Fuchun Li Yujiao Wang Xulong Wang Fei Zhang Liumei Chen Jinhua Du article Ariztegui20151655 Recently, the discovery of active microbial life in deep-sea sediments has triggered a rapid development of the field known as the “deep biosphere.” Geomicrobiological investigations in lacustrine basins have also shown a substantial microbial impact on lake sediments similar to that described for the marine record. Although only 30 % of the lake sites drilled by the International Continental Drilling Program (ICDP) have included microbial investigations, these lakes cover a relatively wide range of salinities (from 0.15 to 33.8 %), pH (from 6.0 to 9.8) and environmental conditions (from very arid to humid subtropical conditions). Here, we analyze results of very recent ICDP lake sites including subsurface biosphere research from southern Patagonia (Laguna Potrok Aike) to the Levantine area (Dead Sea) as well as the East Anatolian high plateau (Lake Van) and Macedonia (Lake Ohrid). These various settings allow the examination of the impact of contrasting environments on microbial activity and their subsequent role during early diagenesis. Furthermore, they permit the identification of biosignatures of former microbial activity recorded in the sediments as well as investigating the impact of microbes in biogeochemical cycles. One of the general outcomes of these preliminary investigations is data to support the hypothesis that microbes react to climatically driven environmental changes that have a direct impact on their subsurface distribution and diversity. This is clear at conspicuous levels associated with well-known climatic periods such as the Medieval Climatic Anomaly or the Little Ice Age. Although more research is needed, this relationship between prevailing microbial assemblages and different climatic settings appears to dominate the lacustrine sites studied until to date. © 2015, The Author(s). 2015 English 14373254 10.1007/s00531-015-1148-4 International Journal of Earth Sciences 104 Springer Verlag 1655-1665 Department of Earth Sciences, University of Geneva, rue des Maraichers 13, Geneva, 1205, Switzerland; Section 4.5 Geomicrobiology, Helmholtz Centre Potsdam, GFZ German Research for Geosciences, Potsdam, 14473, Germany 6 biosphere; deep-sea sediment; diagenesis; drilling; environmental change; genomics; geological record; geomicrobiology; lacustrine deposit; microbial activity; paleoclimate; sedimentary basin, Argentina; Dead Sea; Laguna Potrok Aike; Lake Ohrid; Lake Van; Levantine Sea; Mediterranean Sea; Patagonia; Santa Cruz [Argentina]; Turkey https://www.scopus.com/inward/record.uri?eid=2-s2.0-84940958158&doi=10.1007%2fs00531-015-1148-4&partnerID=40&md5=0af1c04e97299773cc0ebbf26995db8d cited By 18 D. Ariztegui C. Thomas A. Vuillemin article Ariztegui20151655 Recently, the discovery of active microbial life in deep-sea sediments has triggered a rapid development of the field known as the “deep biosphere.” Geomicrobiological investigations in lacustrine basins have also shown a substantial microbial impact on lake sediments similar to that described for the marine record. Although only 30 % of the lake sites drilled by the International Continental Drilling Program (ICDP) have included microbial investigations, these lakes cover a relatively wide range of salinities (from 0.15 to 33.8 %), pH (from 6.0 to 9.8) and environmental conditions (from very arid to humid subtropical conditions). Here, we analyze results of very recent ICDP lake sites including subsurface biosphere research from southern Patagonia (Laguna Potrok Aike) to the Levantine area (Dead Sea) as well as the East Anatolian high plateau (Lake Van) and Macedonia (Lake Ohrid). These various settings allow the examination of the impact of contrasting environments on microbial activity and their subsequent role during early diagenesis. Furthermore, they permit the identification of biosignatures of former microbial activity recorded in the sediments as well as investigating the impact of microbes in biogeochemical cycles. One of the general outcomes of these preliminary investigations is data to support the hypothesis that microbes react to climatically driven environmental changes that have a direct impact on their subsurface distribution and diversity. This is clear at conspicuous levels associated with well-known climatic periods such as the Medieval Climatic Anomaly or the Little Ice Age. Although more research is needed, this relationship between prevailing microbial assemblages and different climatic settings appears to dominate the lacustrine sites studied until to date. © 2015, The Author(s). Review 2015 English 14373254 10.1007/s00531-015-1148-4 International Journal of Earth Sciences 104 Springer Verlag 1655 – 1665 Department of Earth Sciences, University of Geneva, rue des Maraichers 13, Geneva, 1205, Switzerland; Section 4.5 Geomicrobiology, Helmholtz Centre Potsdam, GFZ German Research for Geosciences, Potsdam, 14473, Germany 6 Argentina; Dead Sea; Laguna Potrok Aike; Lake Ohrid; Lake Van; Levantine Sea; Mediterranean Sea; Patagonia; Santa Cruz [Argentina]; Turkey; biosphere; deep-sea sediment; diagenesis; drilling; environmental change; genomics; geological record; geomicrobiology; lacustrine deposit; microbial activity; paleoclimate; sedimentary basin https://www.scopus.com/inward/record.uri?eid=2-s2.0-84940958158&doi=10.1007%2fs00531-015-1148-4&partnerID=40&md5=0af1c04e97299773cc0ebbf26995db8d Cited by: 18; All Open Access, Green Open Access, Hybrid Gold Open Access Daniel Ariztegui Camille Thomas Aurèle Vuillemin article Quek20152303 The Bukit Bunuh in Malaysia has recently been identified as an impact structure after the discovery of possible impact-melt-like rocks and impact breccias from this area. The impact event is believed to have occurred around 1.34-1.84 Ma. Twelve impact-related rocks from this suspected impact structure were analysed in the present study for platinum group of element (PGE) content. The sample population includes proximal impactites (two impact-melt rocks and three impact breccias) and possible impact-related rocks (four mylonites) and basement granite (three in number). The results showed no observable clear distinction between the impactites and basement granite. Compared to other asteroid impact sites in the world, the impactites and impact-related rocks in the Bukit Bunuh structure clearly contain a lower concentration of PGEs. Even though previous studies reported possible evidences of shock metamorphism in the Bukit Bunuh structure and electrical resistivity survey favoured the presence of asteroid impact structure in this area as well, the absence of a clear projectile signature in our study on PGE hinders further discussion on the existence and nature of the impact. We suggest that the absence of any PGE signature in the Bukit Bunuh impactites could be indicative either of (1) an achondrite projectile, or (2) an oblique impact or (3) the presence of a volatile-rich layer. 2015 10.18520/v109/i12/2303-2308 Current Science 109 2303-2308 Department of Geology, University of Malaya, Kuala Lumpur, 50603, Malaysia; Centre for Global Archaeological Research, Universiti Sains Malaysia, Penang, 11800, Malaysia; Institute of Petroleum Engineering, Heriot-Watt University Precinct 2, Putrajaya, 62100, Malaysia 12 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84953397795&doi=10.18520%2fv109%2fi12%2f2303-2308&partnerID=40&md5=e575bd065591609be464969ae3595296 cited By 0 L.X. Quek A.A. Ghani M.H. Badruldin M. Saidin Z.Z.T. Harith M.H. Roselee article Wittmann2015326 The Northwest Africa (NWA) 7475 meteorite is one of the several stones of paired regolith breccias from Mars based on petrography, oxygen isotope, mineral compositions, and bulk rock compositions. Its inventory of lithic clasts is dominated by vitrophyre impact melts that were emplaced while they were still molten. Other clast types include crystallized impact melt rocks, evolved plutonic rocks, possible basalts, contact metamorphosed rocks, and siltstones. Impact spherules and vitrophyre shards record airborne transport, and accreted dust rims were sintered on most clasts, presumably during residence in an ejecta plume. The clast assemblage records at least three impact events, one that formed an impact melt sheet on Mars ≤4.4 Ga ago, a second that assembled NWA 7475 from impactites associated with the impact melt sheet at 1.7-1.4 Ga, and a third that launched NWA 7475 from Mars ~5 Ma ago. Mildly shocked pyroxene and plagioclase constrain shock metamorphic conditions during launch to >5 and <15 GPa. The mild postshock-heating that resulted from these shock pressures would have been insufficient to sterilize this water-bearing lithology during launch. Magnetite, maghemite, and pyrite are likely products of secondary alteration on Mars. Textural relationships suggest that calcium-carbonate and goethite are probably of terrestrial origin, yet trace element chemistry indicates relatively low terrestrial alteration. Comparison of Mars Odyssey gamma-ray spectrometer data with the Fe and Th abundances of NWA 7475 points to a provenance in the ancient southern highlands of Mars. Gratteri crater, with an age of ~5 Ma and an apparent diameter of 6.9 km, marks one possible launch site of NWA 7475. © The Meteoritical Society, 2015. 2015 10.1111/maps.12425 Meteoritics and Planetary Science 50 326-352 Department of Earth and Planetary Sciences, Washington University in St. Louis, Campus Box 1169, 1 Brookings Dr., St. Louis, MI 63130-4899, United States; Department of Earth and Space Sciences, University of Washington, 4000 15 Avenue NE, Seattle, WA 98195, United States; Department of Earth Sciences, University of Western Ontario, 1151 Richmond Street N., London, ON N6A 5B7, Canada; Geophysical Laboratory, Carnegie Institution of Washington, Washington, DC 20015, United States 2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84923028390&doi=10.1111%2fmaps.12425&partnerID=40&md5=7a2cb49f9dd5e88fa4100f3ad6e9cff6 cited By 76 A. Wittmann R.L. Korotev B.L. Jolliff A.J. Irving D.E. Moser I. Barker D. Rumble article Macdonald20151 Nemrut volcano, adjacent to Lake Van (Turkey), is one of the most important peralkaline silicic centres in the world, where magmatism for ~570,000 years has been dominated by peralkaline trachytes and rhyolites. Using onshore and Lake Van drill site tephra samples, we document the phenocryst and glass matrix compositions, confirming a complete spectrum from very rare mafic to dominantly silicic magmas. Magma mixing has been common and, along with the multi-lineage nature of the magmas, indicates that Nemrut has been a very open system where, nevertheless, compositionally zoned caps developed during periods of relative eruptive quiescence. Geothermometry suggests that the intermediate-silicic magmas evolved in an upper crustal magma reservoir at temperatures between 1100 and 750 °C, at fO2 close to the FMQ buffer. The silicic magmas either were halogen poor or exsolved a halogen-rich phase prior to or during eruption. An unusual Pb-rich phase, with up to 98.78 wt% PbO, is interpreted as having exsolved from the intermediate-rhyolitic magmas. © 2015, The Author(s). 2015 English 00107999 10.1007/s00410-015-1127-6 Contributions to Mineralogy and Petrology 169 Springer Verlag 1-22 IGMP Faculty of Geology, University of Warsaw, Żwirki i Wigury 93, Warsaw, 02-089, Poland; Environment Centre, Lancaster University, Lancaster, LA1 4YQ, United Kingdom; Geomar Helmholtz Centre for Ocean Research Kiel, Wischhofstr. 1, Kiel, 24148, Germany; Department of Geography and Geology, Eastern Kentucky University, Richmond, KY 40475, United States 4 felsic rock; geothermometry; glass; magmatism; peralkaline rock; phenocryst; rhyolite; tephra; trachyte, Bitlis; Lake Van; Nemrut; Turkey, Trachytes https://www.scopus.com/inward/record.uri?eid=2-s2.0-84925719387&doi=10.1007%2fs00410-015-1127-6&partnerID=40&md5=48df4b3690f2f4556618e4ca01bcdb33 cited By 18 R. Macdonald M. Sumita H.-U. Schmincke B. Bagiński J.C. White S.S. Ilnicki article Montinaro2015311 Mass-dependent and mass-independent sulfur isotope fractionation archived in volcanic and sedimentary rocks from the Barberton Greenstone Belt (3550-3215. Ma), South Africa, provide constraints for sulfur cycling on the early Earth. Four different sample suites were studied: komatiites and tholeiites, barite, massive and disseminated sulfide ores, and non-mineralized black shales.Variable but generally slightly positive δ34S values between -0.7 and +5.2‰, negative δ33S values between -0.50 and -0.09‰, and a negative correlation between δ34S and δ33S as well as between δ33S and δ36S for komatiites and tholeiites from the Komati Formation and from the Weltevreden Formation are outside the expected range of unfractionated juvenile sulfur. Instead, results suggest alteration of oceanic crustal rock sulfur through interactions with fluids that most likely derived their sulfur from seawater.Barite from the Mapepe Formation displays positive δ34S values between +3.1 and +8.1‰ and negative δ33S values between -0.77 and -0.34‰. The mass-independent sulfur isotope fractionation indicates an atmospheric sulfur source, notably photolytic sulfate, whereas the positive δ34S values suggest bacterial sulfate reduction of the marine sulfate reservoir.Non-mineralized black shale samples from the presumed stratigraphic equivalent of the Mapepe Formation show positive δ34S values between 0.0 and +1.3‰ and positive δ33S values between +0.59 and +2.45‰. These results are interpreted to result from the reduction of photolytic elemental sulfur, carrying a positive δ33S signature.Positive δ34S values ranging from +0.7 to +3.5‰ and slightly negative δ33S values between -0.17 and -0.12‰ characterize massive and disseminated sulfides from the Bien Venue Prospect. Results suggest unfractionated juvenile magmatic sulfur source as the primary sulfur source, but a contribution from recycled seawater sulfate, which would be indicative of submarine hydrothermal activity, cannot be ruled out.Massive and disseminated sulfides from the M'hlati prospect are distinctly different from massive and disseminated sulfide from the Bien Venue Prospect. They show negative δ34S values between -1.2 and -0.1‰ and positive δ33S values between +2.66 and +3.17‰, thus, displaying a sizeable mass-independent sulfur isotopic fractionation. Again, these samples clearly exhibit the incorporation of an atmospheric MIF-S signal. The source of sulfur for these samples has positive δ33S values, suggesting a connection with photolytic elemental sulfur.In conclusion, the sulfur isotope signatures in Paleoarchean rocks from the Barberton Greenstone Belt are diverse and indicate the incorporation of different sources of sulfur. For komatiites and tholeiites, barite and massive and possibly also disseminated sulfides from Bien Venue, multiple sulfur isotopes are related to ambient seawater sulfate and its photolytic origin, while massive and disseminated sulfides from M'hlati and non-mineralized black shales are related to a second (photolytic elemental sulfur) end member. © 2015 Elsevier B.V. Article 2015 English 03019268 10.1016/j.precamres.2015.06.008 Precambrian Research 267 Elsevier 311 – 322 Barberton Greenstone Belt; Bacteria (microorganisms); Archean; black shale; hydrochemistry; isotopic fractionation; komatiite; oceanic crust; paleoceanography; reduction; seawater; sulfate; sulfur isotope https://www.scopus.com/inward/record.uri?eid=2-s2.0-84937920693&doi=10.1016%2fj.precamres.2015.06.008&partnerID=40&md5=cfbdbdc9eacfee8adddb68282340b1ea Cited by: 26; All Open Access, Bronze Open Access, Green Open Access Alice Montinaro Harald Strauss Paul R.D. Mason Desiree Roerdink Carsten Münker Ulrich Schwarz-Schampera Nicholas T. Arndt James Farquhar Nicolas J. Beukes Jens Gutzmer Marc Peters article lorenz_h._operational_2015 2015 10.2312/ICDP.2015.002 55 https://doi.org/10.2312/ICDP.2015.002 00000 H. Lorenz J. E. Rosberg C. Juhlin L. Bjelm B. Almquist T. Berthet R. Conze D. Gee I. Klonowska C. Pascal K. Pedersen N. Roberts C. F. Tsang article Yabe20155574 Using a network of sensitive high-frequency acoustic emission sensors, we observed foreshock activity of an Mw 2.2 earthquake (main shock) in a deep gold mine in South Africa. Foreshock activity, which selectively occurred on a part of the rupture plane of the forthcoming main shock, lasted for at least 6 months until the main shock. Rock samples recovered from the main shock source region showed evidence of ancient hydrothermal alteration on the main shock rupture plane, suggesting that the foreshock activity occurred on a preexisting weakness. The foreshocks during 3 months before the main shock were concentrated in three clusters (F1-F3), which we interpret as representing localized preslip at multiple sites. While the location of mining area, the source of stress perturbations, changed with time, the locations of foreshock clusters did not change, suggesting that the preslip patches were controlled by strength heterogeneity rather than stress distribution. Activity over the entire foreshock area was generally constant, but the largest cluster (F2) showed accelerated activity starting at least 7 days before the main shock, while mining stress did not increase in this period. The main shock initiated at a point close to F1, away from F2. All the six foreshocks during the final 41 h occurred in F1 and F2 and in-between. These suggest that in the last stage of the preparation process of the main shock, preslip patches interacted with each other through the stress concentration ahead of the expanding preslip patch (F2), which should be the only driving force of the preparation process under the constant external load. ©2015. American Geophysical Union. All Rights Reserved. 2015 English 21699313 10.1002/2014JB011680 Journal of Geophysical Research: Solid Earth 120 Blackwell Publishing Ltd 5574-5594 Research Center for Prediction of Earthquakes and Volcanic Eruptions, Graduate School of Science, Tohoku University, Sendai, Japan; Earthquake Research Institute, University of Tokyo, Tokyo, Japan; Department of Civil and Earth Resource Engineering, Graduate School of Engineering, Kyoto University, Kyoto, Japan; GMuG Gesellschaft für Materialprüfung und Geophysik, Bad Nauheim, Germany; GFZ German Research Centre for Geosciences Helmholtz Centre Potsdam, Potsdam, Germany; Now at Japan Atomic Energy Agency, Ibaraki, Japan; College of Science and Engineering, Ritsumeikan University, Kusatsu, Japan; Now at Hitachi Solutions Ltd., Tokyo, Japan 8 acoustic emission; earthquake magnitude; earthquake rupture; fault; foreshock; gold mine; hydrothermal alteration; mining-induced seismicity; nucleation, South Africa https://www.scopus.com/inward/record.uri?eid=2-s2.0-84942552528&doi=10.1002%2f2014JB011680&partnerID=40&md5=dac2840bf08cc545ea9f6de0e2557497 cited By 22 Y. Yabe M. Nakatani M. Naoi J. Philipp T. Watanabe T. Katsura H. Kawakata D. Georg H. Ogasawara article martin2015multiple 2015 Earth and Planetary Science Letters 424 Elsevier 226--236 Adam P Martin AR Prave DJ Condon Aivo Lepland Anthony E Fallick AE Romashkin PV Medvedev DV Rychanchik article Nuhn201565 The ~31.7-km-diameter Betio crater (23.15°S, 281.38°E), located within the Hesperian-aged Ridged Plains material in Thaumasia Planum, Mars, contains a wellpreserved asymmetrical central floor pit (~10.8 km NW-SE and ~8.8 km NE-SW in diameter) covering an area of ~67 km2 that exposes discrete megablocks of layered bedrock and preserves a variety of impact-generated deposits. High-resolution images taken by the Mars Reconnaissance Orbiter (MRO) are combined with other data sets to study and map the morphology and structure of the central floor pit. The excellent bedrock exposure of the floor pit enables the comparison of mapped structures with observations from terrestrial craters. Our mapping of the central uplift has revealed a variety of faults, folds (likely radial transpression ridges), and many breccia dikes, in addition to different types of impactites (e.g., breccias, impact melt deposits, and uplifted bedrock [i.e., parautochthonous bedrock]). Through structural mapping, we show that the central portion of the central uplift is characterized by smaller (~60- 300 m in diameter) blocks with high dips of ~45°-85°, and the outer sections of the floor pit have larger (>800 m in diameter) blocks with shallow dip angles of ~5°-15°. Our work shows that extensive brittle deformation and brecciation increase toward the center of the crater and particularly in the SW sector of the central pit. There is also an overall decrease in block size toward the center of the crater. © 2015 The Geological Society of America. All rights reserved. 2015 10.1130/2015.25184 Special Paper of the Geological Society of America 518 65-83 Department of Earth Sciences, Centre for Planetary Science and Exploration, University of Western Ontario, London, ON N6A 5B7, Canada; Department of Physics and Astronomy, University of Western Ontario, London, ON N6A 5B7, Canada; Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721, United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-84948459145&doi=10.1130%2f2015.25184&partnerID=40&md5=0cdca396b8477759c3a5fe24dd25e556 cited By 4 A.M. Nuhn L.L. Tornabene G.R. Osinski A.S. McEwen article Larsen2015103 The origin of clays and clay minerals in the Paleocene Clayton (CF) and Porters Creek (PCF) Formations within the Mississippi embayment of central North America has been debated for more than 50 years. X-ray diffraction and petrographic analysis of samples of the CF and PCF from a mine in southeastern Missouri are used to evaluate contributions from Cretaceous-Paleogene (K-Pg) impact debris and the role of sediment diagenesis in the fine-grained sediment. Expandable clay minerals increase in abundance relative to illite and kaolinite above the K-Pg unconformity in the CF and PCF, and include dioctahedral smectite, vermiculite, and minor mixed-layered clay components, along with trioctahedral smectitic clays in the CF and lowermost PCF. Additional diagenetic phases include clinoptilolite (in the CF and lower PCF), pyrite, siderite, and opal CT (mainly in the PCF). The results of the petrographic analysis show no evidence for volcanic ash contributing directly to the sediment in the PCF. The detrital silicate minerals are mainly quartz, muscovite, biotite, and metamorphic minerals, consistent with an ancestral Appalachian Mountains source rather than volcanic ash or a Cretaceous western interior sediment source. The illite, kaolinite, dioctahedral smectite, and ordered illite-smectite mixed-layered clays are present in varying quantities in Cretaceous through Paleogene marine and nonmarine mudstones from the Mississippi embayment, and appear to be detrital in origin. Trioctahedral smectite and clinoptilolite in the CF and lowermost PCF are argued to derive from alteration of glassy impact debris; clasts in the basal CF contain microtektites replaced by trioctahedral smectitic mixed-layered clay with randomly interstratified illite. The X-ray diffraction characteristics of the vermiculite in the PCF indicate a hydroxyl-interlayered aluminous variety that is argued to have a diagenetic origin, formed by clay mineral reactions under variably anoxic conditions in the PCF sediments during early diagenesis. Throughout the CF and PCF, pyrite precipitated under reducing conditions during diagenesis, locally along with siderite replacement of micritic carbonate. In addition, opal-CT precipitated as a result of silicate reactions and dissolution of diatoms under alkaline conditions and replaced matrix and calcitic microfossils throughout much of the upper PCF. © 2015 The Geological Society of America. All rights reserved. 2015 10.1130/2015.2515(06) Special Paper of the Geological Society of America 515 103-123 Department of Earth Sciences, University of Memphis, Memphis, TN 38152, United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-84941754174&doi=10.1130%2f2015.2515%2806%29&partnerID=40&md5=a3f0b2042e9fa3ce38b371b36325411a cited By 0 D. Larsen D.J. Ashe J. Gustavson article Mormone201539 A 506. m drill-hole has been recently drilled in the framework of the Campi Flegrei Deep Drilling Project (CFDDP) and the International Continental Scientific Drilling Program (ICDP) with the intention of coring the subsurface in the eastern sector of the Campi Flegrei caldera. The borehole, located in the western district of the Neapolitan city (Bagnoli Plain) 3. km to the east of the most active volcanic area and about 5. m above sea level, is now targeted for monitoring purposes.This paper reports the results obtained from the analysis of two short cores collected at depths of -443 and -506m below the ground level. The cores sampled two pre-caldera tuffs. Observations performed by optical and scanning electron microscopy, energy dispersive spectroscopy and powder X-ray diffraction were used to achieve data on the primary lithology, both primary and secondary mineralogical assemblages, and the relationship between texture and secondary mineralization. Sr isotope ratios were determined on selected primary feldspars, whereas δ13C and δ18O analyses were performed on carbonates from veins and filled-voids in tuffs.Our results provide information on the hydrothermal system in the eastern sector of the caldera that was not among the goals in the previous drilling programs. Secondary mineralization suggests a saline hydrothermal environment characterized by fluids that progressively evolved from boiling toward more alkaline and cooler conditions. A paleo-temperature of ca. 160. °C has been inferred from authigenic mineral occurrences and calculated on the basis of equilibria between cored calcites and fluids presently emitted at the surface, by using carbon and oxygen isotope data. The temperature measured at the bottom of the drilling is about 80. °C. © 2014 The Authors. Review 2015 English 03770273 10.1016/j.jvolgeores.2014.12.003 Journal of Volcanology and Geothermal Research 290 Elsevier 39 – 52 Istituto Nazionale di Geofisica e Vulcanologia, Osservatorio Vesuviano, Naples, Italy; Dipartimento di Scienze della Terra, Dell'Ambiente e delle Risorse, Università Federico II, Naples, Italy; GeoZentrum Nordbayern, University of Erlangen-Nuremberg, Erlangen, Germany Bagnoli; Campania [Italy]; Campi Flegrei; Italy; Naples; Napoli [Campania]; C (programming language); Core samples; Drills; Energy dispersive spectroscopy; Geothermal fields; Isotopes; Lithology; Mineralogy; Rock drills; Scanning electron microscopy; Sea level; Strontium; Volcanoes; X ray diffraction; Authigenic minerals; Campi Flegrei; Carbon and oxygen isotopes; Continental scientific drillings; Hydrothermal activity; Hydrothermal environment; Pilot holes; Powder X ray diffraction; borehole; caldera; deep drilling; geothermal system; hydrothermal activity; hydrothermal system; isotopic ratio; mineralization; strontium isotope; temperature; tuff; Boreholes https://www.scopus.com/inward/record.uri?eid=2-s2.0-84921314458&doi=10.1016%2fj.jvolgeores.2014.12.003&partnerID=40&md5=4ecc1e886fba62b4eca2de0a6c8efa27 Cited by: 22; All Open Access, Hybrid Gold Open Access A. Mormone C. Troise M. Piochi G. Balassone M. Joachimski G. De Natale article Liberty2015919 Hotspot: The Snake River Geothermal Drilling Project was undertaken to better understand geothermal systems across the Snake River Plain volcanic province. A series of surface and borehole seismic profiles were obtained to provide insights into volcanic stratigraphy and test the capabilities of engineering-scale seismic imaging in such terranes. The Kimberly site drilled through 1.9 km of mostly rhyolite, with thin sedimentary interbeds in the upper part of the section. The Kimama site drilled through 1.9 km of mostly basalt with sedimentary interbeds at ∼200 m depth and 1700 m depth. The Mountain Home site contained numerous sediment and volcanic rock layers. Downhole and surface vibroseis seismic results suggest sedimentary interbeds at depth correspond with low-velocity, high-temperature zones that relate to reflections on seismic profiles. Our results suggest that eruption flow volumes can be estimated and flow boundaries can be imaged with surface seismic methods using relatively high-fold and wide-angle coverage. High-frequency attenuation is observed at all sites, and this deficit may be countered by acquisition design and a focus on signal processing steps. Separation of surface and body waves was obtained by muting, and the potential for large static effects was identified and addressed in processing. An accurate velocity model and lithology contacts derived from borehole information improved the confidence of our seismic interpretations. © 2015 European Association of Geoscientists & Engineers. 2015 English 00168025 10.1111/1365-2478.12277 Geophysical Prospecting 63 919-936 Boise State University, Department of Geosciences, 1910 University Drive, Boise, ID 83725-1536, United States; Institute for Geophysical Research, Department of Physics, University of Alberta, Edmonton, AB T6G 2E1, Canada; Department of Geology, Utah State University, 4505 Old Main Hill, Logan, UT 843224905, United States 4 Boreholes; Geothermal fields; Geothermal wells; Infill drilling; Lithology; Rivers; Sedimentology; Seismic waves; Seismology; Signal processing; Stratigraphy; Volcanoes, Geothermal; Geothermal drilling; Geothermal systems; High frequency attenuation; High temperature zones; Seismic imaging; Seismic interpretation; Snake river plains, Volcanic rocks, body wave; borehole; data interpretation; geothermal system; imaging method; seismology; signal processing; volcanic rock, Idaho; Snake River Plain; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-84937978127&doi=10.1111%2f1365-2478.12277&partnerID=40&md5=b9b7f5079d15f25c6e9f5c05d1eba720 cited By 3 L.M. Liberty J.W. Shervais article Gao2015287 The Late Cretaceous (late Campanian to Maastrichtian) was characterized by a variable greenhouse climate, with evidence for cooling and/or glaciation and warming events. Most of these climatic signals are derived from marine records, and knowledge of the terrestrial climate, especially in the mid-latitudes, is limited due to fragmentary geological records on continents. Here we report mid-latitude terrestrial stable oxygen and carbon isotope data from pedogenic carbonates in the nearly continuous Late Cretaceous age SK-1 core drilled in the Songliao Basin, northeastern China. Our data indicate a punctuated, mid-latitude terrestrial climate in the Late Cretaceous. We interpret the negative excursion of pedogenic carbonate δ18O in the early Maastrichtian to be the result of decreasing temperature and/or strengthened westerlies during global cooling and possible glaciation, providing valuable mid-latitude terrestrial evidence for this event. The negative δ13C isotopic excursion ca. 66 Ma is modeled as higher primary productivity caused by increasing temperature and precipitation in response to a warming climate in the latest Cretaceous. Our continuous stable isotopic records in the Songliao Basin are in accordance with previously published global Late Cretaceous records of climate variability from marine and terrestrial regions, and demonstrate the sensitivity of mid-latitude terrestrial climate in a greenhouse world. © 2015 Geological Society of America. 2015 English 00917613 10.1130/G36427.1 Geology 43 Geological Society of America 287-290 State Key Laboratory of Biogeology and Environmental Geology, School of Earth Sciences and Resources, China University of Geosciences (Beijing), Beijing, 100083, China; Department of Environmental Earth System Science, Stanford University, Stanford, CA 94305, United States; Department of Geological and Environmental Sciences, Stanford University, Stanford, CA 94305, United States; State Key Laboratory of Biogeology and Environmental Geology, School of Ocean Sciences, China University of Geosciences (Beijing), Beijing, 100083, China 4 Greenhouses; Isotopes; Temperature, Carbon isotopes; Climate variability; Climatic signals; Greenhouse climates; Increasing temperatures; Pedogenic carbonates; Primary productivity; Warming climate, Glacial geology, carbon isotope; carbonate; climate variation; Cretaceous; global climate; midlatitude environment; oxygen isotope; paleoclimate; stable isotope, China; Far East; Songliao Basin https://www.scopus.com/inward/record.uri?eid=2-s2.0-84939121346&doi=10.1130%2fG36427.1&partnerID=40&md5=7e1830be70d982e5a5528aff44fa4d3b cited By 66 Y. Gao D.E. Ibarra C. Wang J.K. Caves C.P. Chamberlain S.A. Graham H. Wu article Mullick2015105 The western Eger rift at the Czech-German border in central Europe is an important geodynamically active area within the European Cenzoic rift system (ECRS) in the forelands of the Alps. Along with two other active areas of the ECRS, the French Massif Central and the east and west Eifel volcanic fields, it is characterized by numerous CO2-rich fluid emission points and frequent micro-seismicity. Existence of a plume(s) is indicated in the upper mantle which may be responsible for these observations. Here we reprocess a pre-existing deep seismic reflection profile '9HR' and interpret the subsurface structures as mapped by seismic reflectivity with previous findings, mainly from seismological and geochemical studies, to investigate the geodynamic activity in the subsurface. We find prominent hints of pathways which may allow magmatic fluids originating in the upper mantle to rise through the crust and cause the observed fluid emanations and earthquake activity. © 2015 Elsevier B.V. Article 2015 English 00401951 10.1016/j.tecto.2015.02.010 Tectonophysics 647 Elsevier B.V. 105 – 111 Alps; Bohemian Massif; Eger; Eifel; France; Germany; Heves; Hungary; Massif Central; Rhineland-Palatinate; Earthquakes; Bohemian massifs; Crustal fluids; Deep seismic reflection profiles; Earthquake activity; Eger rift; Rift systems; Seismic reflectivity; Subsurface structures; Cenozoic; earthquake swarm; geodynamics; rift zone; seismic reflection; seismicity; seismology; upper mantle; Geodynamics https://www.scopus.com/inward/record.uri?eid=2-s2.0-84925966301&doi=10.1016%2fj.tecto.2015.02.010&partnerID=40&md5=215c26146a16ea6ed3b7716d39c29287 Cited by: 11 N. Mullick S. Buske P. Hrubcová B. Ruzek S. Shapiro P. Wigger T. Fischer article article 2015 01 10.18307/2015.0122 Journal of Lake Sciences 27 190-194 Meiyu Liu Jianfang Hu Wan Xiaoqiao article Mousavi20151113 The region of West Bohemia/Vogtland in the Czech-German border area is well known for the repeated occurrence of earthquake swarms, CO2 emanations and mofette fields. We present a local earthquake tomography study undertaken to image the Vp and Vp/Vs structure in the broader area of earthquake swarm activity. In comparison with previous investigations, more details of the near-surface geology, potential fluid pathways and features around and below the swarm focal zone could be revealed. In the uppermost crust, for the first time the Cheb basin and the Bublák/Hartoušov mofette fields were imaged as distinct anomalies of Vp and Vp/Vs. The well-pronounced low-Vp anomaly of the Cheb basin is not continuing into the Eger rift indicating a particular role of the basin within the rift system. A steep channel of increased Vp/Vs is interpreted as the pathway for fluids ascending from the earthquake swarm focal zone up to the Bublák/Hartoušov mofette fields. As a new feature, a mid-crustal body of high Vp and increased Vp/Vs is revealed just below and north of the earthquake swarm focal zone. It may represent a solidified intrusive body which emplaced prior or during the formation of the rift system. We speculate that enhanced fluid flow into the focal zone and triggering of earthquakes could be driven by the presence of the intrusive body if cooling is not fully completed. We consider the assumed intrusive structure as a heterogeneity leading to higher stress particularly at the junction of the rift system with the basin and prominent fault structures. This may additionally contribute to the triggering of earthquakes. © The Authors 2015. Article 2015 English 0956540X 10.1093/gji/ggv338 Geophysical Journal International 203 Oxford University Press 1113 – 1127 2 Germany; Vogtland; Flow of fluids; Seismographs; Body waves; Earthquake swarms; Europe; Fault structure; Fluid pathways; Near-surface geology; Seismic tomography; Seismicity and tectonics; body wave; earthquake swarm; seismic tomography; seismic velocity; seismicity; tectonics; Earthquakes https://www.scopus.com/inward/record.uri?eid=2-s2.0-84966711865&doi=10.1093%2fgji%2fggv338&partnerID=40&md5=37cf0b6092b42b1bacb3080fb8460cb7 Cited by: 20; All Open Access, Bronze Open Access, Green Open Access Sima Mousavi Klaus Bauer Michael Korn Babak Hejrani article Ji2015226 A palynological record recovered from successions of Coniacian to early Campanian age (89.1-83.5Ma) was obtained from the lacustrine sequences of the SK-I south core (SK-Is) in the Songliao Basin, northeastern China. The palynoflora is dominated by bisaccate gymnosperm pollen, followed by spores of pteridophytes, and just minor amounts of angiosperm pollen. Based on the relative abundance of the different spore and pollen taxa through the core, the succession was subdivided into three palynological assemblages. The results indicate two opposite trends for climate change, a minor warming trend (from 89.1 to 85.7Ma) followed by a rapid cooling trend (85.7-83.5Ma). The first warming trend reached its maximum at 85.7Ma, which is inconsistent with results from the marine realm (which instead show a minor cooling trend based on several proxy records). However, the second cooling phase is consistent with global changes from various and abundant palaeoclimate proxies from marine deposits. We interpret the climatic changes within the studied interval (89.1-83.5Ma) as a consequence of the shifting climate from a hot/super greenhouse to a temperate greenhouse. © 2015 Elsevier Ltd. 2015 English 01956671 10.1016/j.cretres.2015.04.006 Cretaceous Research 56 Academic Press 226-236 Key Laboratory of Petroleum Resources, Gansu Province/Key Laboratory of Petroleum Resources Research, Institute of Geology and Geophysics, Chinese Academy of Sciences, Lanzhou, 730000, China; State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, 510640, China Campanian; climate variation; Coniacian; flora; geological record; paleoclimate; palynology; proxy climate record; sequence stratigraphy; temperate environment, China; Songliao Basin, Gymnospermae; Magnoliophyta; Pteridophyta https://www.scopus.com/inward/record.uri?eid=2-s2.0-84936753652&doi=10.1016%2fj.cretres.2015.04.006&partnerID=40&md5=0dbce41de8dc7209e5273c7ca7eb1a31 cited By 12 L. Ji M. Zhang Z. Song article Lacey201513427 Lake Ohrid (Macedonia/Albania) is an ancient lake with a unique biodiversity and a site of global significance for investigating the influence of climate, geological and tectonic events on the generation of endemic populations. Here, we present oxygen (δ18O) and carbon (δ13C) isotope data on carbonate from the upper ca. 248 m of sediment cores recovered as part of the Scientific Collaboration on Past Speciation Conditions in Lake Ohrid (SCOPSCO) project, covering the past 640 ka. Previous studies on short cores from the lake (up to 15 m, < 140 ka) have indicated the Total Inorganic Carbon (TIC) content of sediments to be highly sensitive to climate change over the last glacial-interglacial cycle, comprising abundant endogenic calcite through interglacials and being almost absent in glacials, apart from discrete bands of early diagenetic authigenic siderite. Isotope measurements on endogenic calcite(δ18Oc and δ13Cc) reveal variations both between and within interglacials that suggest the lake has been subject to hydroclimate fluctuations on orbital and millennial timescales. We also measured isotopes on authigenic siderite (δ18Os and δ13Cs) and, with the δ18OCc and δ18Os, reconstruct δ18O of lakewater (δ18Olw) through the 640 ka. Overall, glacials have lower δ18Olw when compared to interglacials, most likely due to cooler summer temperatures, a higher proportion of winter precipitation (snowfall), and a reduced inflow from adjacent Lake Prespa. The isotope stratigraphy suggests Lake Ohrid experienced a period of general stability through Marine Isotope Stage (MIS) 15 to MIS 13, highlighting MIS 14 as a particularly warm glacial, and was isotopically freshest during MIS 9. After MIS 9, the variability between glacial and interglacial δ18Olw is enhanced and the lake became increasingly evaporated through to present day with MIS 5 having the highest average δ18Olw. Our results provide new evidence for long-term climate change in the northern Mediterranean region, which will form the basis to better understand the influence of major environmental events on biological evolution within the lake. © Author(s) 2015. Article 2015 English 18106277 10.5194/bgd-12-13427-2015 Biogeosciences Discussions 12 Copernicus GmbH 13427 – 13481 16 Lake Mikri Prespa; Lake Ohrid; Mediterranean Region; biodiversity; calcite; carbon isotope; endemic species; glacial-interglacial cycle; lacustrine deposit; lake water; Mediterranean environment; oxygen isotope; Pleistocene; population structure; sediment core; siderite; stable isotope; temperature effect https://www.scopus.com/inward/record.uri?eid=2-s2.0-85031984646&doi=10.5194%2fbgd-12-13427-2015&partnerID=40&md5=8e4e32ba360229b7bd1653cff3a1e904 Cited by: 6; All Open Access, Green Open Access J.H. Lacey M.J. Leng A. Francke H.J. Sloane A. Milodowski H. Vogel H. Baumgarten B. Wagner article kraus_zero-offset_2015 2015 Geophysical Research Abstracts 17 EGU2015--3255 http://meetingorganizer.copernicus.org/EGU2015/EGU2015-3255.pdf 00000 Felix Krauß Helge Simon Rüdiger Giese Peter Hedin Christopher Juhlin Henning Lorenz article Puchtel20152369 The start of plate tectonics on Earth is one of the most controversial issues in modern geology, with proposed timings covering almost the entire history of our planet. On page 2387 of this issue (vol. 100, 2015), Blichert-Toft and co-authors report Sm-Nd and Lu-Hf isotopic and lithophile trace element data for early Archean komatiites from the Barberton Greenstone Belt (GB) in South Africa, and argue for the onset of plate tectonics on Earth as early as 3.5 Ga. The studied komatiites show a large decoupling of the two isotopic systems and lithophile trace element signatures that are most consistent with deep-water, pelagic sediments being present in the lower-mantle source of these lavas. Their conclusions have far-reaching implications for advancing our understanding of how the Earth system operated in the distant geological past. © Walter de Gruyter Berlin/Boston 2015. Article 2015 English 0003004X 10.2138/am-2015-5468 American Mineralogist 100 Walter de Gruyter GmbH 2369 – 2370 11-12 Barberton Greenstone Belt; Belt conveyors; Binary alloys; Earth (planet); Isotopes; Lutetium alloys; Neodymium alloys; Samarium alloys; Tectonics; Trace elements; Barberton; Conveyor belts; Element signatures; Greenstone belts; Hf isotope; Isotopic systems; Pelagic sediments; subduction; greenstone belt; hafnium; isotopic analysis; komatiite; lutetium; neodymium; plate tectonics; samarium-neodymium dating; subduction; Hafnium alloys https://www.scopus.com/inward/record.uri?eid=2-s2.0-84948823083&doi=10.2138%2fam-2015-5468&partnerID=40&md5=6f20fa7d73830bb0ea97cb1ef1f8f6c5 Cited by: 1 Igor S. Puchtel article Fanara20152284 The solubility of H2O- and CO2-bearing fluids in trachytic and trachybasaltic melts from erupted magmas of the Campi Flegrei Volcanic District has been investigated experimentally at 1100 and 1200 °C, respectively, and at 100, 200, 300, 400, and 500 MPa. The solubility of H2O in the investigated melts varies between 3.48 ± 0.07 wt% at 100 MPa to 10.76 ± 0.12 wt% at 500 MPa in trachytic melts and from 3.49 ± 0.07 wt% at 100 MPa to 9.10 ± 0.11 wt% at 500 MPa in trachybasaltic melts. The content of dissolved CO2 in melts coexisting with the most CO2-rich fluid phase increases from 281 ± 24 ppm at 100 MPa to 2710 ± 99 ppm at 500 MPa in trachyte, and from 727 ± 102 ppm at 100 MPa to 3565 ± 111 ppm at 500 MPa in trachybasalt. Natural samples from the Campanian Ignimbrite eruption (trachyte) and from the Solchiaro eruption (trachybasalt) were collected around the city of Naples and on Procida Island. Deuterium/hydrogen (D/H) ratios were analyzed in natural pumices pre-heated at different temperatures to remove water adsorbed and/or imprinted by glass alteration processes. It has been determined that heating of the glass to 350 °C efficiently removes most of secondary water and the remaining concentrations represent primary magmatic water preserved in the erupted material. Hydrogen isotope composition (with δD values ranging between -70‰ and -110‰) and its correlation with bulk water content in selected pumice samples of the Campanian Ignimbrite eruption are consistent with isotopic fractionation between magmatic fluid and melt during degassing of erupting magma. Hence, the H2O and CO2 contents in natural glasses from pumice samples are considered as minimum estimates on volatile concentrations in the melt just prior to the eruption or at the fragmentation event. The water contents in natural glasses vary from 0.83 ± 0.07 to 3.74 ± 0.06 wt% for trachytes from the Campanian Ignimbrite eruption and from 1.96 ± 0.06 to 3.47 ± 0.07 wt% for trachybasalts from the Solchiaro eruption. The CO2 contents vary from 78 ± 120 ppm CO2 to 1743 ± 274 ppm for trachytes from the Campanian Ignimbrite eruption and from 240 ± 293 to 1213 ± 250 ppm for trachybasalts from the Solchiaro eruption. A combination of natural and experimental data provides minimum pressure estimates for the storage and ascent conditions of magmas. The Campanian Ignimbrite magma could have been stored or ponded during its rising path at two different levels: a deeper one corresponding to depth of about 8 to 15 km and a shallower one at about 1 to 8 km. Trachybasalts from Solchiaro erupted from the deepest level of about 11 km with a storage or ponding level at around 2 to 8 km depth. Although an uncertainty of at least a kilometer has to be considered in estimating storage or ponding depths, these estimates point to significantly deeper magmatic sources for both eruptions as those considered previously. © 2015 by Walter de Gruyter Berlin/Boston. Article 2015 English 0003004X 10.2138/am-2015-5033 American Mineralogist 100 Walter de Gruyter GmbH 2284 – 2297 10 Campania [Italy]; Campi Flegrei; Italy; Napoli [Campania]; Trachytes; Carbon dioxide process; Digital storage; Glass; Isotopes; Ponding; Solubility; Storage (materials); Uncertainty analysis; Volcanoes; Water; Campanian Ignimbrite; Hydrogen isotope; Solchiaro eruption; trachybasalt; trachyte; Volcanic district; Campanian; carbon dioxide; hydrogen isotope; ignimbrite; isotopic fractionation; magma chemistry; solubility; trachyte; volatile substance; volcanic eruption; water content; Carbon dioxide https://www.scopus.com/inward/record.uri?eid=2-s2.0-84943530641&doi=10.2138%2fam-2015-5033&partnerID=40&md5=77161ef51085f932e043c45a959f13c8 Cited by: 27 Sara Fanara Roman E. Botcharnikov Danilo M. Palladino Franziska Adams Julia Buddensieck Andreas Mulch Harald Behrens article Pickarski2015145 A high-resolution multi-proxy record from Lake Van, eastern Anatolia, derived from a lacustrine sequence cored at the 357m deep Ahlat Ridge (AR), allows a comprehensive view of paleoclimate and environmental history in the continental Near East during the last interglacial (LI). We combined paleovegetation (pollen), stable oxygen isotope (δ18Obulk) and XRF data from the same sedimentary sequence, showing distinct variations during the period from 135 to 110ka ago leading into and out of full interglacial conditions. The last interglacial plateau, as defined by the presence of thermophilous steppe-forest communities, lasted ca. 13.5ka, from ~129.1-115.6ka BP.The detailed palynological sequence at Lake Van documents a vegetation succession with several climatic phases: (I) the Pistacia zone (ca. 131.2-129.1. ka BP) indicates summer dryness and mild winter conditions during the initial warming, (II) the Quercus-. Ulmus zone (ca. 129.1-127.2. ka BP) occurred during warm and humid climate conditions with enhanced evaporation, (III) the Carpinus zone (ca. 127.2-124.1. ka BP) suggest increasingly cooler and wetter conditions, and (IV) the expansion of Pinus at ~. 124.1. ka BP marks the onset of a colder/drier environment that extended into the interval of global ice growth. Pollen data suggest migration of thermophilous trees from refugial areas at the beginning of the last interglacial. Analogous to the current interglacial, the migration documents a time lag between the onset of climatic amelioration and the establishment of an oak steppe-forest, spanning 2.1. ka. Hence, the major difference between the last interglacial compared to the current interglacial (Holocene) is the abundance of Pinus as well as the decrease of deciduous broad-leaved trees, indicating higher continentality during the last interglacial. Finally, our results demonstrate intra-interglacial variability in the low mid-latitudes and suggest a close connection with the high-frequency climate variability recorded in Greenland ice cores. © 2015 Elsevier B.V. 2015 English 00310182 10.1016/j.palaeo.2015.06.015 Palaeogeography, Palaeoclimatology, Palaeoecology 435 Elsevier 145-158 University of Bonn, Steinmann Institute for Geology, Mineralogy and Paleontology, Nussallee 8, Bonn, D-53115, Germany; Ruhr-University Bochum, Institute for Geology, Mineralogy and Geophysics, Universitätsstrasse 150, Bochum, D-44801, Germany; Institut Méditerranéen de Biodiversite et d'Ecologie marine et continentale (IMBE), UMR CNRS 7263/IRD 237, Aix-Marseille Université, Technopôle de l'Environnement Arbois-Méditerranée, BP 80, Aix-en-Provence cedex 04, F-13545, France abundance; climate conditions; climate variation; community structure; coniferous tree; data set; deciduous tree; environmental change; environmental history; lacustrine deposit; Last Interglacial; oxygen isotope; paleoecology; palynology; pollen; proxy climate record; resolution; stable isotope; steppe; succession; temperature effect; vegetation structure; X-ray fluorescence, Anatolia; Arctic; Greenland; Greenland Ice Sheet; Lake Van; Turkey, Carpinus; Pistacia; Quercus; Ulmus https://www.scopus.com/inward/record.uri?eid=2-s2.0-84934914233&doi=10.1016%2fj.palaeo.2015.06.015&partnerID=40&md5=be68b8f603b0f7dfc24fe52911a4a0c2 cited By 39 N. Pickarski O. Kwiecien M. Djamali T. Litt article Tamuntuan2015163 We investigated the mineral-magnetic behavior of sediments from Lake Towuti located in the Eastern Sulawesi Ophiolite belt, Indonesia. Rock magnetic analysis supplemented by X-ray diffraction and scanning electron microscopy analysis were performed on sediment core TOW10-9B from the north basin of Lake Towuti to give insights on the environmental and sedimentary processes controlling the magnetic properties of the sediment and its paleoclimatic significance. The results show that the core has three distinct zones of varying magnetic properties. Careful examination demonstrates that these zones correspond to varying levels of iron oxide dissolution and magnetite precipitation that are climatically and environmentally dependent. The magnetically strongest zone is characterized by weak iron oxide dissolution and intense magnetite precipitation, likely driven by changes in the stratification and/or water level of the lake during dry conditions in Marine Isotope Stage 2 (MIS2) period, whereas the two magnetically weaker zones are characterized by signs of dissolution and correspond to relatively wet conditions, respectively, during Marine Isotope Stage 3 (MIS3) and the Holocene. Although our data show that major changes in concentration dependent parameters, such as magnetic susceptibility and saturation isothermal remanent magnetization (SIRM), in Lake Towuti sediment correlate with changes in regional rainfall, many of the concentration changes are more strongly affected by in situ chemical processes than by changes in erosion and terrestrial sediment supply. These findings urge caution in the interpretation of magnetic mineral concentration profiles as indicators of clastic sediment inputs. © 2014 Elsevier B.V. Article 2015 English 00310182 10.1016/j.palaeo.2014.12.008 Palaeogeography, Palaeoclimatology, Palaeoecology 420 Elsevier 163 – 172 Greater Sunda Islands; Lake Towuti; Malili Lakes; South Sulawesi; Sulawesi; Sunda Isles; clastic sediment; core analysis; depositional environment; dissolution; Holocene; lacustrine deposit; magnetic mineral; magnetic property; marine isotope stage; ophiolite; paleoclimate; sediment property https://www.scopus.com/inward/record.uri?eid=2-s2.0-84920896688&doi=10.1016%2fj.palaeo.2014.12.008&partnerID=40&md5=fe3642ee04d5cf20b2ebfe4eedbd7a98 Cited by: 30 Gerald Tamuntuan Satria Bijaksana John King James Russell Umar Fauzi Khoiril Maryunani Nurul Aufa La Ode Safiuddin article Baker201541 This article presents the scientific rationale for an ambitious ICDP drilling project to continuously sample Late Cretaceous to modern sediment in four different sedimentary basins that transect the equatorial Amazon of Brazil, from the Andean foreland to the Atlantic Ocean. The goals of this project are to document the evolution of plant biodiversity in the Amazon forests and to relate biotic diversification to changes in the physical environment, including climate, tectonism, and the surface landscape. These goals require long sedimentary records from each of the major sedimentary basins across the heart of the Brazilian Amazon, which can only be obtained by drilling because of the scarcity of Cenozoic outcrops. The proposed drilling will provide the first long, nearly continuous regional records of the Cenozoic history of the forests, their plant diversity, and the associated changes in climate and environment. It also will address fundamental questions about landscape evolution, including the history of Andean uplift and erosion as recorded in Andean foreland basins and the development of west-to-east hydrologic continuity between the Andes, the Amazon lowlands, and the equatorial Atlantic. Because many modern rivers of the Amazon basin flow along the major axes of the old sedimentary basins, we plan to locate drill sites on the margin of large rivers and to access the targeted drill sites by navigation along these rivers. © Author(s) 2015. 2015 English 18168957 10.5194/sd-20-41-2015 Scientific Drilling 20 Copernicus GmbH 41-49 Earth and Ocean Sciences, Duke University, Durham, NC 27708, United States; Yachay Tech University, San Miguel de Urcuquí, Imbabura, Ecuador; Earth and Atmospheric Sciences, University of Nebraska - Lincoln, Lincoln, NE 68588-0340, United States; Departamento de Geologia, Universidade Federal Fluminense, Niterói, Brazil; Department of Geological Sciences, East Carolina University, Greenville, NC, United States; Instituto Nacional de Pesquisas da Amazônia, Manaus, Brazil; School of Arts, Sciences and Humanities, Universidade de São Paulo, São Paulo, Brazil; Geoarte Consultoria Geológica e Artística Ltda, Belém, Brazil; Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, United States; Department of Earth Sciences, University of Southern California, Los Angeles, CA, United States; OGX Oil and Gas, Brazil; Department of Geosciences, Pennsylvania State University, State CollegePA, United States; Institute for Biodiversity and Ecosytem Dynamics, University of Amsterdam, Amsterdam, Netherlands; Smithsonian Tropical Research Institute, Panama City, Panama; Department of Geography, University of Texas, Austin, TX, United States; Institut de Recherche pour le Développement, Université de Montpellier, Montpellier, France; Dipartimento di Geoscienze, Universitá Degli Studi di Padova, Padua, Italy; Limnological Research Center, University of Minnesota - Twin Cities, Minneapolis, MN, United States; Institute of Earth Sciences, Universität Graz, Graz, Austria; Museu Paraense Emílio Goeldi, Pára, Brazil; Faculdade de Oceanografia, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, Brazil; Departamento de Geociências, Universidade Federal do Amazonas, Manaus, Brazil; US Geological Survey, Reston, VA, United States Biodiversity; Drills; Plants (botany); Rivers; Sedimentology; Settling tanks, Brazilian Amazon; Cenozoic history; Drilling projects; Landscape evolutions; Physical environments; Plant diversity; Sedimentary basin; Sedimentary records, Forestry https://www.scopus.com/inward/record.uri?eid=2-s2.0-84951921499&doi=10.5194%2fsd-20-41-2015&partnerID=40&md5=365d1b9954c02b9dcd4791c05bacf6c1 cited By 9 P.A. Baker S.C. Fritz C.G. Silva C.A. Rigsby M.L. Absy R.P. Almeida M. Caputo C.M. Chiessi F.W. Cruz C.W. Dick S.J. Feakins J. Figueiredo K.H. Freeman C. Hoorn C. Jaramillo A.K. Kern E.M. Latrubesse M.P. Ledru A. Marzoli A. Myrbo A. Noren W.E. Piller M.I.F. Ramos C.C. Ribas R. Trnadade A.J. West I. Wahnfried D.A. Willard article Farber2015134 Pervasive silicification is a common phenomenon in Early Archaean volcano-sedimentary sequences, reflecting the interaction between Si-rich fluids and the Archaean oceanic crust. In the Palaeoarchaean Barberton greenstone belt, South Africa, the silicified zones locally contain abundant tourmaline. In order to constrain the source of fluids responsible for the alteration, six tourmaline-bearing samples from the 3.3. Ga Mendon Formation were investigated by in-situ analyses of mineral chemistry and boron isotopes. The samples comprise a silicified, finely laminated sedimentary chert and five highly altered and silicified komatiites. Electron microprobe analysis (EMPA) indicates that tourmaline is mostly dravitic, with one sample between dravite and Mg-foitite. Tourmaline has a weakly-developed patchy colour- and chemical zonation, with variations in Al, Fe and Mg composition. Some samples show strong zoning in Cr-concentration with Cr enrichment in the core, and locally the high-Cr domains are at contacts with other Cr-rich phases such as magnesiochromite and chromian muscovite ("fuchsite").Overall, the boron isotope composition (δ11B) ranges from -20.7 to +10.2‰. Two groups of tourmaline are distinguished based on the variation in δ11B ratios within single samples: 1) those with small (<4‰) range in δ11B values (spinifex-textured komatiites and silicified sediment), and 2) those with a large range in δ11B values of up to 18‰ (brecciated and foliated samples). Positive boron isotope values (+6 to +10‰) are found in one spinifex-textured komatiite and are interpreted as being derived from seawater interacting with Archaean oceanic crust in shallow hydrothermal systems. The intermediate boron isotope values (-5 to -8‰) found in all other samples are similar to MORB and may represent boron derived from the Archaean oceanic crust. The rare and exceptionally light boron isotope values (-10 to -21‰) were found in rims of group 2 tourmaline. These values cannot be produced by fractionation alone, and point to the presence of another fluid source. The source of the light boron has yet to be identified, but possible candidates are remobilized boron either derived from granitic crust or from marine evaporites that precipitated from seawater enriched in 10B. In any case, the isotopically light boron appears to have been present during seafloor hydrothermal alteration and deposition of the Mendon Formation at ca. 3.3Ga. © 2015 Elsevier B.V. Article 2015 English 00092541 10.1016/j.chemgeo.2015.10.009 Chemical Geology 417 Elsevier 134 – 147 Barberton Greenstone Belt; Chemical analysis; Clay alteration; Electron probe microanalysis; Isotopes; Magnesium; Mica; Microanalysis; Seawater; Secondary ion mass spectrometry; Sedimentology; Silicate minerals; Zoning; Boron isotopes; Greenstone belts; Hydrothermal alterations; Hydrothermal system; Marine evaporites; Mendon Formation; Tourmaline; Volcano-sedimentary sequences; Archean; boron isotope; concentration (composition); evaporite; hydrothermal alteration; igneous geochemistry; isotopic composition; isotopic fractionation; komatiite; oceanic crust; tourmaline; tracer; Boron https://www.scopus.com/inward/record.uri?eid=2-s2.0-84945118316&doi=10.1016%2fj.chemgeo.2015.10.009&partnerID=40&md5=0fd48e0c9def483071d211db33f23038 Cited by: 15 Katja Farber Annika Dziggel Robert B. Trumbull F. Michael Meyer Michael Wiedenbeck article Jackson201551 A new International Continental Drilling Program (ICDP) project will drill through the 50-year-old edifice of Surtsey Volcano, the youngest of the Vestmannaeyjar Islands along the south coast of Iceland, to perform interdisciplinary time-lapse investigations of hydrothermal and microbial interactions with basaltic tephra. The volcano, created in 1963-1967 by submarine and subaerial basaltic eruptions, was first drilled in 1979. In October 2014, a workshop funded by the ICDP convened 24 scientists from 10 countries for 3 and a half days on Heimaey Island to develop scientific objectives, site the drill holes, and organize logistical support. Representatives of the Surtsey Research Society and Environment Agency of Iceland also participated. Scientific themes focus on further determinations of the structure and eruptive processes of the type locality of Surtseyan volcanism, descriptions of changes in fluid geochemistry and microbial colonization of the subterrestrial deposits since drilling 35 years ago, and monitoring the evolution of hydrothermal and biological processes within the tephra deposits far into the future through the installation of a Surtsey subsurface observatory. The tephra deposits provide a geologic analog for developing specialty concretes with pyroclastic rock and evaluating their long-term performance under diverse hydrothermal conditions. Abstracts of research projects are posted at http://surtsey. icdp-online.org. © Author(s) 2015. 2015 English 18168957 10.5194/sd-20-51-2015 Scientific Drilling 20 Copernicus GmbH 51-58 Department of Civil and Environmental Engineering, University of California, Berkeley, CA, United States; Nordvulk, Institute of Earth Sciences, University of Iceland, Reykjavík, Iceland; University of Bremen, Department of Geosciences, Bremen, Germany; Dipartimento di Scienze della Terra, dell'Ambiente e delle Risorse (DiSTAR), University FEDERICO II, Naples, Italy; Department of Pharmaceutical, Chemical and Environmental Science, University of Greenwich, Kent, United Kingdom; Department of Palaeobiology, Swedish Museum of Natural History, Stockholm, Sweden; Icelandic Institute of Natural History, Gardabaer, Iceland; Centre for Geobiology, Department of Biology, University of Bergen, Norway; Matís, Food Safety, Environment and Genetics, Reykjavík, Iceland; Agricultural University of Iceland, Hvanneyri, Borgarnes, 311, Iceland; Department of Earth Sciences, University of Tasmania, Hobart, Australia; U.S. Geological Survey, Menlo Park, CA, United States; DOSECC Exploration Services, 2075 Pioneer Rd., Salt Lake City, UT, United States; Department of Geosciences, University of Massachusetts, Amherst, United States; Department of Geology, University of California, Davis, CA, United States; Stanford Rock Physics Laboratory, Geophysics Department, Stanford, CA, United States; ÍSOR, Iceland GeoSurvey, Reykjavík, Iceland; Geology Department, University of Otago, Dunedin, New Zealand; Institut für Geographie und Geologie, Universität Würzburg, Würzburg, Germany Biology; Deposits; Drills; Volcanoes, Basaltic eruptions; Environment Agency; Hydrothermal conditions; Logistical support; Long term performance; Microbial colonization; Microbial interactions; Scientific objectives, Basalt https://www.scopus.com/inward/record.uri?eid=2-s2.0-84951973508&doi=10.5194%2fsd-20-51-2015&partnerID=40&md5=de8a864c39c0aa822696816a0455e48d cited By 12 M.D. Jackson M.T. Gudmundsson W. Bach P. Cappelletti N.J. Coleman M. Ivarsson K. Jónasson S.L. Jørgensen V. Marteinsson J. McPhie J.G. Moore D. Nielson J.M. Rhodes C. Rispoli P. Schiffman A. Stefánsson A. Türke T. Vanorio T.B. Weisenberger J.D.L. White R. Zierenberg B. Zimanowski article just2015tmoi 2015 10.1594/PANGAEA.848638 Institute of Geology and Mineralogy, University of Cologne PANGAEA PANGAEA https://doi.org/10.1594/PANGAEA.848638 Janna Just Norbert R Nowaczyk Alexander Francke Leonardo Sagnotti Bernd Wagner conference Welhan2015363 Data on temperature and chemistry of thermally-influenced ground water in the eastern Snake River Plain aquifer were examined to determine how such information could be used to inform on heat transport from the hot rhyolitic rocks that underlie the aquifer. The U.S. Geological Survey's NWIS database reveals the existence of several thermally-influenced areas located near the margins of the aquifer, where ground water temperatures are associated with distinctive water chemistry. The associated enrichments in F, Li and B in these waters are diagnostic of water-rock chemical reactions with felsic rocks under thermal conditions. The chemistry of thermal waters sampled in a deep borehole drilled into rhyodacite and welded tuff beneath the Idaho National Laboratory (INL) to a depth of 3.2 km bears the geochemical fingerprint of such interaction with hot felsic rock. Based on an analysis of temperature data in a thermal anomaly located in the central ESRP aquifer south of the INL, an estimate of the thermal water flux through the base of the aquifer, derived via a two-component mixing model, is incompatible with core-scale data on hydraulic conductivity (K) of the rhyolite. This suggests that advective heat transport from the rhyolite is not spatially uniform but focused in localized, high-K preferential flow paths within the rhyolite and mineralized basalts that overlie the rhyolite. This interpretation is consistent with data on the fracture-flow characteristics of rhyolitic basement and sheds new light on the spatial distribution of thermally influenced ground water near the margins of the ESRP aquifer in the area of the INL. 2015 English 9781510817241 01935933 Transactions - Geothermal Resources Council 39 Geothermal Resources Council 363-375 Idaho Geological Survey, Idaho State University, Pocatello, ID, United States Aquifers; Fluorine; Geothermal fields; Granite; Groundwater; Groundwater flow; Groundwater resources; Heat transfer; Rocks; Trace elements, Chemical tracers; Conceptual model; ESRP; Rhyolite; Thermal waters, Hydrochemistry https://www.scopus.com/inward/record.uri?eid=2-s2.0-84962866769&partnerID=40&md5=9d2729f2508d461cbf55bcd9aa21d9ce cited By 0 J.A. Welhan article Ledevin2015253 In the Barberton Greenstone Belt, South Africa, a 100-250 m thick complex of carbonaceous chert dikes marks the transition from the Mendon Formation to the Mapepe Formation (3260 Ma). The sub-vertical-to vertical position of the fractures, the abundance of highly shattered zones with poorly rotated angular fragments and common jigsaw fit, radial structures, and multiple injection features point to repetitive hydraulic fracturing that released overpressured fluids trapped within the shallow crust. The chemical and isotopic compositions of the chert favour a model whereby seawater-derived fluids circulated at low temperature (< 100-150 °C) within the shallow crust. From the microscopic structure of the chert, the injected material was a slurry of abundant clay-sized, rounded particles of silica, carbonaceous matter and minor clay minerals, all suspended in a siliceous colloidal solution. The dike geometry and characteristics of the slurry concur on that the chert was viscoelastic, and most probably thixotropic at the time of injection: the penetration of black chert into extremely fine fractures is evidence for low viscosity at the time of injection and the suspension of large country rock fragments in the chert matrix provides evidence of high viscosity soon thereafter. We explain the rheology by the particulate and colloidal structure of the slurry, and by the characteristic of silica suspensions to form cohesive 3-D networks through gelation. <br><br> Our results provide valuable information about the compositions, physical characteristics and rheological properties of the fluids that circulated through Archean volcano-sedimentary sequences, which is an additional step to understand conditions on the floor of Archean oceans, the habitat of early life. Article 2015 English 18699510 10.5194/se-6-253-2015 Solid Earth 6 Copernicus GmbH 253 – 269 1 Barberton Greenstone Belt; Complex networks; Fracture; Fracturing fluids; Gelation; Hydraulic fracturing; Hydraulic structures; Levees; Silica; Temperature; Viscosity; Colloidal structures; Isotopic composition; Microscopic structures; Multiple injections; Physical characteristics; Rheological behaviour; Rheological property; Volcano-sedimentary sequences; Archean; chert; dike; fracture; greenstone belt; isotopic composition; rheology; viscosity; Suspensions (fluids) https://www.scopus.com/inward/record.uri?eid=2-s2.0-84923332286&doi=10.5194%2fse-6-253-2015&partnerID=40&md5=ef1ddfa1609be50788d12b2b08dc99b1 Cited by: 9; All Open Access, Gold Open Access, Green Open Access M. Ledevin N. Arndt A. Davaille R. Ledevin A. Simionovici article Zhao2015167 The 318-m-thick sediment record from Lake El'gygytgyn provides unique opportunities for a detailed examination of environmental changes during the Réunion Subchron polarity reversal event (2.1384-2.1216. Myr. BP) in the northeastern Russian Arctic. The paper describes vegetation and climate fluctuations between ~. 2.15 and 2.10. Myr. BP as inferred from palynological data. Biome reconstructions indicate that throughout this interval the tundra (TUND) biome generally has higher affinity scores as compared to cold steppe (STEP) or cold deciduous forest (CLDE). An exception is the climatic optimum between ~. 2.139 and 2.131. Myr. BP, coinciding with Marine Isotope Stage 81 (approximately the Réunion Subchron), when the CLDE biome has the highest scores. Landscape-openness indices suggest that more closed vegetation characterized most of the interval between 2.146 and 2.127. Myr. BP, when deciduous forest and shrubs expanded in the regional vegetation and climate was relatively warm and wet. Peaks in green algal colonies (Botryococcus) and Zygnema-type spores ~. 2.150-2.146, ~. 2.131-2.123, and ~. 2.112-2.102. Myr. BP indicate expansions of shallow-water habitats and lowered lake levels. Comparisons with biome reconstructions from other interglacial intervals at Lake El'gygytgyn suggest that precession-related summer insolation intensity and obliquity-related duration of summer daylight are major controls on the onset of interglaciations, whereas obliquity probably plays a more significant role on vegetation succession at northern high latitudes during the Pleistocene. © 2015 Elsevier B.V. 2015 English 00310182 10.1016/j.palaeo.2015.06.047 Palaeogeography, Palaeoclimatology, Palaeoecology 436 Elsevier 167-177 Institute of Geology and Mineralogy, University of Cologne, Cologne, 50674, Germany; Institute of Geology and Petroleum Technologies, Kazan Federal University, Kazan, 420008, Russian Federation; Institute of Geological Sciences, Palaeontology Section, Free University of Berlin, Malteserstrae 74-100, Building D, Berlin, 12249, Germany; Earth and Space Sciences, Quaternary Research Center, University of Washington, Seattle, WA 98195, United States; Northeast Interdisciplinary Research Institute, Far East Branch Russian Academy of Sciences, Magadan, 685000, Russian Federation biome; climate variation; environmental change; interglacial; lake ecosystem; paleoclimate; paleoecology; paleoenvironment; palynology; Pleistocene; regional pattern; succession; vegetation history; deciduous forest; green alga; marine isotope stage; orbital forcing; precession; reconstruction; steppe, Chukchi; Elgygytgyn Lake; Mascarene Islands; Reunion; Russian Federation; Arctic https://www.scopus.com/inward/record.uri?eid=2-s2.0-84937891650&doi=10.1016%2fj.palaeo.2015.06.047&partnerID=40&md5=68dc8935b60b6b67955f8956e8e21e6f cited By 11 W.W. Zhao A.A. Andreev V. Wennrich P.E. Tarasov P. Anderson A.V. Lozhkin M. Melles article cao2015distribution 2015 Geochimica 44 536-545 XX Cao Y Li L Wang Q Yin ZG Song DF Zhao article Ikari20151523 The Alpine Fault is a major plate-boundary fault zone that poses a major seismic hazard in southern New Zealand. The initial stage of the Deep Fault Drilling Project has provided sample material from the major lithological constituents of the Alpine Fault from two pilot boreholes. We use laboratory shearing experiments to show that the friction coefficient µ of fault-related rocks and their precursors varies between 0.38 and 0.80 depending on the lithology, presence of pore fluid, effective normal stress, and temperature. Under conditions appropriate for several kilometers depth on the Alpine Fault (100 MPa, 160 °C, fluid-saturated), a gouge sample located very near to the principal slip zone exhibits µ = 0.67, which is high compared with other major fault zones targeted by scientific drilling, and suggests the capacity for large shear stresses at depth. A consistent observation is that every major lithological unit tested exhibits positive and negative values of friction velocity dependence. Critical nucleation patch lengths estimated using representative values of the friction velocity-dependent parameter a−b and the critical slip distance Dc, combined with previously documented elastic properties of the wall rock, may be as low as ~3 m. This small value, consistent with a seismic moment Mo = ~4 × 1010 for an Mw = ~1 earthquake, suggests that events of this size or larger are expected to occur as ordinary earthquakes and that slow or transient slip events are unlikely in the approximate depth range of 3–7 km. © 2015, The Author(s). 2015 English 14373254 10.1007/s00531-014-1115-5 International Journal of Earth Sciences 104 Springer Verlag 1523-1535 MARUM, Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany; Istituto Nazionale di Geofisica e Vulcanologia, Rome, Italy 6 borehole; drilling; fault zone; friction; seismic hazard; seismic moment; shear stress; slip rate, Alpine Fault Zone; New Zealand; South Island https://www.scopus.com/inward/record.uri?eid=2-s2.0-84940954040&doi=10.1007%2fs00531-014-1115-5&partnerID=40&md5=96a5360201521a57f77b5c6fa6e27de2 cited By 13 M.J. Ikari S. Trütner B.M. Carpenter A.J. Kopf inproceedings simon_derivation_2015 The project COSC (Collisional Orogeny in the Scandinavian Caledonides) focuses on the mid Paleozoic Caledonide Orogen in Scandinavia in order to better understand orogenic processes, from the past and in recent active mountain belts. The Scandinavian Caledonides provide a well preserved example of a Paleozoic continent-continent collision, where the surface geology in combination with geophysical data provide control of the geometry of the Caledonian structure. In 2014 the COSC-1 borehole was successfully drilled through the Seve Nappe Complex (SNC) to {\textasciitilde} 2.5 km depth near the town of Åre (central Sweden). Subsequently a major seismic survey was conducted in and around the COSC-1 borehole which comprised both seismic reflection and transmission experiments. This will allow extrapolation of results from core analysis and downhole logging to the structures around the borehole. The survey consisted of three simultaneous experiments: 1) a high-resolution zero-offset Vertical Seismic Profile (VSP), 2) a multi-azimuthal walkaway VSP in combination with three long offset surface receiver lines, and 3) a limited 3D seismic survey. In this study data from the multi-azimuthal walkaway VSP experiment and the long offset surface lines were used to derive a detailed velocity model around the borehole from the inversion of first arrival traveltimes. The P-wave velocity profile at the borehole obtained by this tomography approach correlates in general with sonic velocities measured during borehole logging and with interval velocities calculated from the zero-offset VSP data, however the absolute values are always significantly higher. This is probably due to the presence of significant seismic anisotropy in the SNC which has also been observed in ultrasonic lab measurements. The obtained anisotropic velocity model serves as the basis for the ongoing application of imaging approaches like pre-stack depth migration techniques. 2015 American Geophysical Union

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H11B--1327 https://agu.confex.com/agu/fm15/meetingapp.cgi/Paper/71897 00000 Helge Simon Felix Krauß Peter Hedin Rüdiger Giese Christopher Juhlin article Wang201599 On the basis of the new results of the CCSD (China Cretaceous Continental Scientific Drilling) and the integrated information concerning tectonic basin classification and 3-D description of the Songliao Basin (SB), we reevaluate the type, tectonic evolution, and geodynamics of the SB according to systematical analysis of tectonic setting and basin fillings. The SB is on the northeast marginal zone of Mongolia-North China Plate. It is united with the Siberian Plate by the Mongolia-Okhotsk suture belt to the north, and connected with the Pacific Plate by Sikhote-Alin accretionary belt to the east. The vertical filling successions of the SB can be subdivided into three tectono-stratigraphic units by two regional unconformities which are on the top boundaries of the Yingcheng (K1y) (ca. 110 Ma) and Nenjiang (K2n) (ca. 79.1 Ma) Formations, respectively. The three tectono-stratigraphic units are block faulting (Huoshiling to Yingcheng Formations), interior sag (Denglouku to Nenjiang Formations), and structural inversion (Sifangtai to Yi'an Formations) sequences. The block faulting sequence is a kind of volcanic rift basin, and the latter two all belong to the type of interior sag basin. In the block faulting period (150-110 Ma), syn-rift volcanogenic successions were formed under the impact of regional extension that may be caused by the Plate reorganization from two sides, the northern and eastern active continental margins. The post-rift basin fills (110-79.1 Ma) may result from the superimposed subsidence of both post volcanic thermal declining and regional strike-slip pull-apart effect. Widespread and thick source rocks deposited because of the high rate and under-compensation of sedimentation in this period. In the structural inversion period (79.1-40 Ma), depocenter of the SB migrated northwestward, and the basin was shrinking to demise. This was a result of the regional compression that should be caused by the Pacific Plate subduction under the eastern margin of the Eurasian Plate in the Mid-Cretaceous to the Middle Eocene. ©, 2015, The Editorial Office of Earth Science Frontiers. All right reserved. 2015 Chinese 10052321 10.13745/j.esf.2015.03.009 Earth Science Frontiers 22 Science Frontiers editorial department 99-117 College of Earth Sciences, Jilin University, Changchun, 130061, China; Exploration and Development Research Institute of Daqing Oilfield Company Ltd., Daqing, 163712, China; Research Center of Palaeontology & Stratigraphy, Jilin University, Changchun, 130026, China 3 Classification (of information); Faulting; Geodynamics; Stratigraphy; Volcanoes, Continental scientific drillings; Integrated informations; North China; Songliao basin; Stratigraphic units; Systematical analysis; Tectonic evolution; Volcanic rifts, Plates (structural components) https://www.scopus.com/inward/record.uri?eid=2-s2.0-84930425321&doi=10.13745%2fj.esf.2015.03.009&partnerID=40&md5=4ca975df6aa8e94fa95f4a4545dca1b3 cited By 37 P. Wang R. Zhao Q. Meng X. Qu D. Zhu Y. Gao article Wang2015 2015 English 21979545 Springer Geology Springer Engineering Center of Chinese Continental Scientific Drilling Project, Beijing, China https://www.scopus.com/inward/record.uri?eid=2-s2.0-85067971013&partnerID=40&md5=61103f2056f2fd9cc5f6e93f55c29498 cited By 0 Da Wang Wei Zhang Xiaoxi Zhang Guolong Zhao Ruqiang Zuo Jialu Ni Gansheng Yang Jun Jia Kaihua Yang Yongyi Zhu others article li2015carbon 2015 Geochimica 44 337-347 4 WANG Li CAO Xinxing LI Yan others article Bolte2015 The magma storage conditions of the 6.62 Ma Blacktail Creek Tuff eruption, belonging to the Heise volcanic field (6.62–4.45 Ma old) of the Yellowstone hotspot system, have been investigated by combining thermobarometric and experimental approaches. The results from different geothermometers (e.g., Fe–Ti oxides, feldspar pairs, apatite and zircon solubility, and Ti in quartz) indicate a pre-eruptive temperature in the range 825–875 °C. The temperature estimated using two-pyroxene pairs varies in a range of 810–950 °C, but the pyroxenes are probably not in equilibrium with each other, and the analytical results of melt inclusion in pyroxenes indicate a complex history for clinopyroxene, which hosts two compositionally different inclusion types. One natural Blacktail Creek Tuff rock sample has been used to determine experimentally the equilibrium phase assemblages in the pressure range 100–500 MPa and a water activity range 0.1–1.0. The experiments have been performed at fluid-present conditions, with a fluid phase composed of H2O and CO2, as well as at fluid-absent conditions. The stability of the quartzo-feldspathic phases is similar in both types of experiments, but the presence of mafic minerals such as biotite and clinopyroxene is strongly dependent on the experimental approach. Possible explanations are given for this discrepancy which may have strong impacts on the choice of appropriate experimental approaches for the determination of magma storage conditions. The comparison of the composition of natural phases and of experimentally synthesized phases confirms magma storage temperatures of 845–875 °C. Melt water contents of 1.5–2.5 wt% H2O are required to reproduce the natural Blacktail Creek Tuff mineral assemblage at these temperatures. Using the Ti-in-quartz barometer and the Qz–Ab–Or proportions of natural matrix glasses, coexisting with quartz, plagioclase and sanidine, the depth of magma storage is estimated to be in a pressure range between 130 and 250 MPa. © 2015, Springer-Verlag Berlin Heidelberg. 2015 English 00107999 10.1007/s00410-015-1112-0 Contributions to Mineralogy and Petrology 169 Springer Verlag Institute of Mineralogy, Leibniz University of Hannover, Callinstraße 3, Hannover, 30167, Germany; Department of Geology and Geophysics, University of Utah, Salt Lake City, UT 84112-011, United States 2 clinopyroxene; hot spot; melt inclusion; meltwater; plagioclase; quartz; rhyolite; sanidine; temperature, Idaho; Snake River Plain; United States; Yellowstone Volcanic Plateau, Gymnocephalus cernuus https://www.scopus.com/inward/record.uri?eid=2-s2.0-84922252893&doi=10.1007%2fs00410-015-1112-0&partnerID=40&md5=542deb402f6566256c2512e26a5f1b91 cited By 28 T. Bolte F. Holtz R. Almeev B. Nash article DiMaggio2015234 The Pliocene Hadar Formation, exposed throughout the lower Awash Valley, Ethiopia, chronicles the evolution and paleoenvironmental context of early hominins. Deposition of the Hadar Formation continued until at least 2.94 Ma, but what transpired in the Hadar Basin after this time remains poorly documented due to an erosional event that truncated the formation throughout much of the valley. Here we present geologic mapping and stratigraphic analysis of a 26 m-thick section of sedimentary rocks and tephras exposed in the Ledi-Geraru project area in the region of Gulfaytu. The section contains Hadar Formation strata younger than 2.94 Ma, and sediments that we interpret are Busidima Formation in age, <2.7 Ma. We use this record to place additional constraints on depositional environments and the tectonic and paleogeomorphic history of the region. The lower ~20 m of section contains lacustrine deposits that conformably overly a 2.94 Ma marker bed (BKT-2U) that previously served as the uppermost dated tephra in the Hadar Formation. We identified seven post-BKT-2U tephras; three were analyzed for glass chemistry, and one yielded an 40Ar/39Ar age of 2.931 ± 0.017 Ma (1σ). Based on these analyses, the newly mapped deposits at Gulfaytu extend the top of the Hadar Formation, representing ca. 20 kyr of post-BKT-2 sedimentation. The Hadar Basin remained depositional following the BKT-2 eruptions, and paleolake Hadar was present at Gulfaytu at this time. An erosional surface marked by a conglomerate truncates the Hadar strata suggesting that the Gulfaytu region was also was influenced by significant changes to basin architecture well-documented elsewhere in the lower Awash Valley. In addition, geophysical models suggest that central Ledi Geraru hosts a thick subsurface lacustrine sedimentary record within the Hadar Basin. The results of this paper provide the outcrop and near surface characterization for the Hominin Sites and Paleolakes Drilling Project (HSPDP) effort at Gulfaytu. © 2015 Elsevier Ltd. Article 2015 English 1464343X 10.1016/j.jafrearsci.2015.09.018 Journal of African Earth Sciences 112 Elsevier Ltd 234 – 250 Afar; depositional environment; geological mapping; hominid; lithostratigraphy; paleoenvironment; Pliocene; tephra; tephrochronology https://www.scopus.com/inward/record.uri?eid=2-s2.0-84943748041&doi=10.1016%2fj.jafrearsci.2015.09.018&partnerID=40&md5=cc1c61efcb676af027c4e4bb4f8ca347 Cited by: 4; All Open Access, Bronze Open Access Erin N. DiMaggio J Ramón Arrowsmith Christopher J. Campisano Roy Johnson Alan L. Deino Mark Warren Shimeles Fisseha Andrew S. Cohen article Carlino201523 Article 2015 English 0012821X 10.1016/j.epsl.2015.03.035 Earth and Planetary Science Letters 420 Elsevier 23 – 29 Campania [Italy]; Campi Flegrei; Italy; Napoli [Campania]; Drilling; Risk assessment; Stresses; Borehole measurements; Caldera unrest; Campi Flegrei; Extensional stress; Improved forecast; Leak-off tests; Principal stress; Volcanic eruptions; caldera; deep drilling; geoaccumulation; stress field; structural geology; tectonic evolution; tectonic setting; uplift; volcanic eruption; volcanology; Volcanoes https://www.scopus.com/inward/record.uri?eid=2-s2.0-84961368077&doi=10.1016%2fj.epsl.2015.03.035&partnerID=40&md5=6123fd676f4f0d265033e7b92e6c4653 Cited by: 21; All Open Access, Green Open Access Stefano Carlino Christopher R.J. Kilburn Anna Tramelli Claudia Troise Renato Somma Giuseppe De Natale article Cvetkoska2015179 Surirella is a polyphyletic and highly diverse diatom genus with more than 500 species described worldwide. Within a study of its diversity and distribution in the Republic of Macedonia, ancient Lake Prespa has been investigated, as “sister” to Lake Ohrid and part of a unique lake system with extraordinary age, biodiversity and number of endemic species. During the study, two new Surirella species have been identified and their LM and SEM based formal descriptions and differential diagnoses are provided herein. Surirella prespanensis sp. nov. has been observed in the contemporary and the fossil diatom flora of the lake. It can be distinguished from other similar taxa by its valve outline, size, shape of the median ridge and the presence of silica grooves along the raphe. Surirella hinziae sp. nov. is known only from the fossil diatom flora of Lake Prespa and can be recognized by its valve outline, size, shape of the median ridge and the presence of helictoglossa-like processes. © Czech Phycological Society (2015). Article 2015 English 18025439 10.5507/fot.2015.018 Fottea 15 Czech phycological Society 179 – 189 2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84943154428&doi=10.5507%2ffot.2015.018&partnerID=40&md5=1b2d57d8565ebf30bffaaed0873de5fb Cited by: 2; All Open Access, Bronze Open Access Aleksandra Cvetkoska Paul B. Hamilton Zlatko Levkov article Marks201534 The Iceland Deep Drilling Program well RN-17 was drilled 3km into a section of hydrothermally altered basaltic crust in the Reykjanes geothermal system in Iceland. The system is located on the landward extension of the Mid-Atlantic Ridge, and the circulating hydrothermal fluid is modified seawater, making Reykjanes a useful analog for mid-oceanic ridge hydrothermal systems. We have determined whole-rock Sr and O isotope compositions, and Sr isotope compositions of epidote grains from the RN-17 cuttings and RN-17B core. Whole rock oxygen isotope ratios range from -0.13 to 3.61‰ V-SMOW, and are isotopically lighter than fresh MORB (5.8±0.2‰). The concentrations of Sr in the altered basalt range from well below to well above concentrations in fresh rock, and appear to be strongly correlated with the dominant alteration mineralogy. Whole rock Sr isotope ratios ranged from 0.70329 in the least altered crystalline basalt, to 0.70609 in the most altered hyaloclastite samples; there is no correlation with depth. Sr isotope ratios in epidote grains measured by laser ablation MC-ICP-MS ranged from 0.70360 to 0.70731. Three depth intervals, at 1000m, 1350m, and 1650m depth, have distinctive isotopic signatures, where 87Sr/86Sr ratios are elevated (mean value>0.7050) relative to background levels (mean altered basalt value ~0.7042). These areas are proximal to geothermal feed zones, and the 1350m interval directly overlies the transition from dominantly extrusive to dominantly intrusive lithologies. Oxygen isotope measurements yield integrated water/rock ratios of 0.4 to 4.3, and suggest that hydrothermal fluids must have formerly had a component of meteoric water. Strontium isotopic measurements provide a more sensitive indication of seawater interaction and require significant exchange with seawater strontium. Both isotopic systems indicate that the greenschist-altered basalts were in equilibrium with hydrothermal fluids at a relatively high mean water/rock (Wt.) ratio ranging from about 0.5 to 4. These ratios are higher than estimates from ODP Hole 504B and IODP Hole 1256D, but are consistent with values inferred from vent fluids from 21° and 13°N on the East Pacific Rise (Albarède et al., 1981; Michard et al., 1984; Alt et al., 1996; Harris et al., 2015). © 2015 Elsevier B.V. 2015 English 00092541 10.1016/j.chemgeo.2015.07.006 Chemical Geology 412 Elsevier 34-47 Department of Geology, University of California, DavisCA 95616, United States Aluminum; Basalt; Crystalline rocks; Geothermal fields; Isotopes; Laser ablation; Minerals; Oxygen; Rocks; Seawater; Silicate minerals, Alteration; Geothermal; Hydrothermal; Icelands; Oxygen isotopes; Reykjanes; Strontium isotopes, Strontium, concentration (composition); geothermal system; hydrothermal alteration; hydrothermal fluid; hydrothermal vent; isotopic composition; mid-ocean ridge basalt; oceanic crust; oxygen isotope; strontium isotope, East Pacific Rise; Iceland; Pacific Ocean; Reykjanes Peninsula https://www.scopus.com/inward/record.uri?eid=2-s2.0-84938090234&doi=10.1016%2fj.chemgeo.2015.07.006&partnerID=40&md5=bbb4285c0d4bc181faff8317b465e9dd cited By 18 N. Marks R.A. Zierenberg P. Schiffman article Chen2015113 To advance the understanding of the spatial variability of sediment composition and its controlling factors in a large hydrologically closed lake, the spatial distributions in the mineralogy and geochemistry of 18 surface sediment samples along three transects across the deepest part of Lake Qinghai on the northeastern Tibetan Plateau were investigated. The data show (1) that the surface lake sediments are almost the same in the XRD patterns, (2) that the sediments do not have considerable changes in geochemical compositions along three transects and (3) that the standard deviations of the lake sediments are low in grain size, elemental abundances, δ13C and δ18O values of carbonates, and total organic carbon and nitrogen, with the exception of one sample (QH-11) from the westernmost part of the northern sub-basin. These characteristics indicate that the spatial variability of the surface sediment across Lake Qinghai is very low in geochemical and silicate mineralogical compositions, with limited differences in the chemical composition of carbonates associated with river water dilution. Sample QH-11 has anomalously high levels of MgO, a high carbonate content, and positive δ13C and δ18O values in bulk and fine-grained carbonates, probably because of the effect of calcareous tufa. Spatial uniformity in the mineralogical and geochemical compositions of surface sediments in Lake Qinghai can be attributed to the flat topography of the lakebed and stable sediment provenances, the latter dominated by dust deposition and authigenic carbonates. The spatial uniformity and dominance of dust and authigenic aragonite of surface sediments across Lake Qinghai provide a potential record of the hydroclimate in the past, which is associated with changes in the Westerlies and the summer monsoons. © 2015, The Japanese Society of Limnology. Article 2015 English 14398621 10.1007/s10201-015-0448-5 Limnology 16 Springer-Verlag Tokyo 113 – 125 2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84939985199&doi=10.1007%2fs10201-015-0448-5&partnerID=40&md5=141a5dd4392cba0f68ad08f7eaeec239 Cited by: 8 Liu-Mei Chen Zhangdong Jin Dejun Wan Fei Zhang article Abed20154025 Twenty-seven samples from Waqf as Suwwan structure in the southeastern desert of Jordan were analyzed for their petrography, mineralogy, and geochemistry. All three types of analysis failed to show any evidence supporting the structure as an impact crater, but they cannot be used as an evidence discrediting the structure as an impact crater. This is because of the presence of shatter cones and rare shock metamorphic features. Shatter cones are well established in the Waqf as Suwwan structures and are accepted internationally as a criterion for impact craters. Shock metamorphic features reported in previous works are extremely rare and atypical. Planar features (PFs) were reported in one single quartz grain taken from a 30-m-thick Kurnub sandstone horizon. They are also reported from one single loose chert nodule, despite the extremely abundant bedded and loose chert within the structure. The PFs in the chert nodule are questioned because they are possibly due to diagenesis. More important is the complete absence of any type of breccias, lithic, melt, or suevitic and ejecta within and around the structure. The "deep erosion of the crater" used by advocates cannot stand for rigorous discussion on the amount of erosion in the desert environment in southeastern Jordan. Given the exact age of the cratering event is not yet known, and an approximate long-term rate of erosion of 1 m/Ma breccias and ejecta should be present in and/or around the structure. © 2014, Saudi Society for Geosciences. 2015 10.1007/s12517-014-1427-6 Arabian Journal of Geosciences 8 4025-4037 Department of Geology, The University of Jordan, Amman, 11942, Jordan; Department of Earth and Environmental Sciences, The Hashemite University, Zarqa, Jordan 6 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84930183291&doi=10.1007%2fs12517-014-1427-6&partnerID=40&md5=dfe31e2b07cf48ab20314af91279d51a cited By 3 A.M. Abed B.S. Amireh K. Al Zghoul article Shervais2015761 The Snake River volcanic province (SRP) overlies a thermal anomaly that extends deep into the mantle; it represents one of the highest heat flow provinces in North America. Our goals for this Phase 1 study are to: (1) adapt the methodology of Play Fairway Analysis for geothermal exploration to create a formal basis for its application to geothermal systems, (2) assemble relevant data for the SRP from publicly available and private sources, and (3) build a geothermal play fairway model for the SRP and identify the most promising plays, using software tools that are standard in the petroleum industry. The success of play fairway analysis in geothermal exploration depends critically on defining a systematic methodology that is grounded in theory (as developed within the petroleum industry over the last two decades) and within the geologic and hydrologic framework of real geothermal systems. Our preliminary assessment of the data suggests that important undiscovered geothermal resources may be located in several areas of the SRP, including the western SRP (associated with buried lineaments defined by gravity or magnetic anomalies, and capped by extensive deposits of lacustrine sediment), at lineament intersections in the central SRP (along the Banbury-Hagerman trend N W of Twin Falls, and along the northern margin of the Mt Bennett Hills-Camas Prairie area), and along the margins of the eastern SRP. Additional high temperature resources are likely associated with rhyolite domes and crypto-domes in the eastern SRP, but are masked by shallow groundwater flow leading to low upper crustal heat flow values. These blind resources may be exploitable with existing deep drilling technology. Groundwater modeling planned for later phases of the PFA project will address whether temperatures at viable producing depths are sufficient to support electricity production. © Copyright (2015) by Geothermal Resources Council All rights reserved. 2015 English 9781510817241 01935933 Transactions - Geothermal Resources Council 39 Geothermal Resources Council 761-769 Department of Geology, Utah State University, Logan, UT, United States; US Geological Survey, Menlo Park, CA, United States; Center for Geophysical Investigation of Shallow Subsurface, Boise State University, Boise, ID, United States; Lawrence Berkeley National Laboratory, Berkeley, CA, United States; National Renewable Energy Laboratory, Golden, CO, United States; DOSECC Exploration Services, LLC., Salt Lake City, UT, United States; Leidos, Inc., San Diego, CA, United States; US Geological Survey, Portland, OR, United States Application programs; Domes; Geothermal fields; Geothermal wells; Groundwater; Groundwater flow; Groundwater resources; Heat transfer; Petroleum industry; Petroleum prospecting; Rivers; Structural geology, Electricity production; Geothermal exploration; Groundwater modeling; Idaho; Play fairway analysis; Preliminary assessment; Snake river plains; Systematic methodology, Geothermal prospecting https://www.scopus.com/inward/record.uri?eid=2-s2.0-84963994586&partnerID=40&md5=009779353fb4453be8913e6ebea395de cited By 3 J.W. Shervais J.M. Glen L.M. Liberty P. Dobson E. Gasperikova E. Sonnenthal C. Visser D. Nielson S. Garg J.P. Evans D. Siler J. Deangelo N. Athens E. Burns book Malde2015255 The vast lowland, known as the Snake River Plain, that stretches across southern Idaho is a Pliocene structural trough filled with a complex sequence of basaltic lava and intercalated detrital deposits more than a kilometer in thickness, much of which is of Quaternary age. The trough at the western end is outlined by a northwest-trending graben 50 km broad, the site of a basin fill of lake and stream deposits rich in molluscan and vertebrate fossils. The eastern plain, on the other hand, a monotonous tract of lava diversified only by numerous subdued volcanic vents, is structurally more like a downwarp. Canyon cutting in the western basin to a depth of 150-300 m gives excellent exposures of the Quaternary deposits and their physiographic relations. A widespread unit of Blancan provincial age at least 600 m thick, characterized by moderately faulted fine-grained sedimentary facies indicative of adjoining environments of lakes, river channels, and swampy flood plains, is beveled by undeformed lower Pleistocene sand and gravel 180-250 m above the present Snake River. A subsequent canyon 250 m deep was filled in middle Pleistocene time by lava flows and by sediments trapped in lakes behind lava dams. These deposits were then beveled by pediment gravel 170 m above the river. Entrenchment of the present Snake River canyon, regarded as a late Pleistocene event, coincided with eruption of the surface lava flows in the eastern plain, which apparently forced the Snake River into its course along the southern margin. Two gravel terraces 120 m and 60 m above the river, which were built between lava eruptions as cutting progressed, include abundant constituents from glaciated mountains in central Idaho and possibly represent glacial outwash. Still younger gravel on the canyon floor, distinguished by enormous boulders heaped in huge bars as much as 90 m high, is attributed to catastrophic overflow of Lake Bonneville about 30,000 years ago. © 1965, by Princeton University Press. All Rights Reserved. 2015 English 9781400876525; 9780691624426 The Quaternary of the U.S. Princeton University Press 255-263 U.S. Geological Survey, Federal Center, Denver, CO, United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-84958656675&partnerID=40&md5=7b8c3ca77a527ee3da747737f42a950d cited By 9 H.E. Malde article French2015827 We report the strength and constitutive behavior of gouge sampled from the Central Deforming Zone (CDZ) of the San Andreas Fault. Layers of flaked CDZ gouge were sheared in the triaxial saw cut configuration using the stress relaxation technique to measure the gouge strength over 4 orders of magnitude in shear strain rate and at rates as low as 5 × 10-10s-1 and within an order of magnitude of in situ rates. Deformation conditions correspond to the in situ effective normal stress (100 MPa) and temperature (65 to 120C) at the sampling depth of 2.7 km. Gouge was sheared dry and with brine pore fluid at 25 MPa pore pressure. Dry gouge is stronger and more rate strengthening than brine-saturated gouge. Brine-saturated CDZ gouge strengthens with increasing strain rate and decreasing temperature, and the dependencies of strength on strain rate and temperature increase at rates below ∼5 × 10-9s-1. At strain rates greater than ∼5 × 10-9s-1, the rate dependence is consistent with previous studies on the CDZ gouge conducted at even higher rates. The increase in rate dependence below ∼5 × 10-9s-1 indicates a change in the rate-controlling deformation mechanism. The magnitude of the friction rate dependence parameter, a, and the temperature sensitivity of a are consistent with crystal plasticity of the phyllosilicates. We hypothesize a micromechanical model for the CDZ gouge whereby a transition from fracture and delamination-accommodated frictional flow to crystal plasticity-accommodated frictional flow occurs with decreasing strain rate. © 2015. American Geophysical Union. All Rights Reserved. 2015 English 21699313 10.1002/2014JB011496 Journal of Geophysical Research: Solid Earth 120 Blackwell Publishing Ltd 827-849 Department of Geology and Geophysics, Center for Tectonophysics, Texas A and M University, College Station, TX, United States; Department of Geology, University of Maryland, College Park, MD, United States 2 clay; creep; deformation mechanism; fault gouge; fault zone; micromechanics; microstructure; San Andreas Fault; strain rate; stress field, California; San Andreas; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-85027948655&doi=10.1002%2f2014JB011496&partnerID=40&md5=b5b21297b826aff0b5b4b4c3fc0c386e cited By 35 M.E. French F.M. Chester J.S. Chester article Kallmeyer20151667 The ICDP “PaleoVan” drilling campaign at Lake Van, Turkey, provided a long (>100 m) record of lacustrine subsurface sedimentary microbial cell abundance. After the ICDP campaign at Potrok Aike, Argentina, this is only the second time deep lacustrine cell counts have been documented. Two sites were cored and revealed a strikingly similar cell distribution despite differences in organic matter content and microbial activity. Although shifted towards higher values, cell counts from Lake Potrok Aike, Argentina, reveal very similar distribution patterns with depth. The lacustrine cell count data are significantly different from published marine records; the most probable cause is differences in sedimentary organic matter composition with marine sediments containing a higher fraction of labile organic matter. Previous studies showed that microbial activity and abundance increase centimetres to metres around geologic interfaces. The finely laminated Lake Van sediment allowed studying this phenomenon on the microscale. We sampled at the scale of individual laminae, and in some depth intervals, we found large differences in microbial abundance between the different laminae. This small-scale heterogeneity is normally overlooked due to much larger sampling intervals that integrate over several centimetres. However, not all laminated intervals exhibit such large differences in microbial abundance, and some non-laminated horizons show large variability on the millimetre scale as well. The reasons for such contrasting observations remain elusive, but indicate that heterogeneity of microbial abundance in subsurface sediments has not been taken into account sufficiently. These findings have implications not just for microbiological studies but for geochemistry as well, as the large differences in microbial abundance clearly show that there are distinct microhabitats that deviate considerably from the surrounding layers. © 2015, The Author(s). 2015 English 14373254 10.1007/s00531-015-1219-6 International Journal of Earth Sciences 104 Springer Verlag 1667-1677 GFZ German Research Centre for Geosciences, Telegrafenberg, Potsdam, 14473, Germany; Earth and Environmental Sciences, University of Potsdam, Karl-Liebknecht Straße, Potsdam, 14476, Germany; Center for Geomicrobiology, Aarhus University, Ny Munkegade 114, Århus C, 8000, Denmark 6 biosphere; lacustrine deposit; microbial activity; microbial community; microbial ecology; relative abundance, Lake Van; Turkey https://www.scopus.com/inward/record.uri?eid=2-s2.0-84940963557&doi=10.1007%2fs00531-015-1219-6&partnerID=40&md5=a75517f084f8dfe188e7cf64a1526c52 cited By 9 J. Kallmeyer S. Grewe C. Glombitza J.A. Kitte article Wiesmaier20151007 In order to explore the materials' complexity induced by bubbles rising through mixing magmas, bubble-advection experiments have been performed, employing natural silicate melts at magmatic temperatures. A cylinder of basaltic glass was placed below a cylinder of rhyolitic glass. Upon melting, bubbles formed from interstitial air. During the course of the experimental runs, those bubbles rose via buoyancy forces into the rhyolitic melt, thereby entraining tails of basaltic liquid. In the experimental run products, these plume-like filaments of advected basalt within rhyolite were clearly visible and were characterised by microCT and high-resolution EMP analyses. <br><br> The entrained filaments of mafic material have been hybridised. Their post-experimental compositions range from the originally basaltic composition through andesitic to rhyolitic composition. Rheological modelling of the compositions of these hybridised filaments yield viscosities up to 2 orders of magnitude lower than that of the host rhyolitic liquid. Importantly, such lowered viscosities inside the filaments implies that rising bubbles can ascend more efficiently through pre-existing filaments that have been generated by earlier ascending bubbles. MicroCT imaging of the run products provides textural confirmation of the phenomenon of bubbles trailing one another through filaments. This phenomenon enhances the relevance of bubble advection in magma mixing scenarios, implying as it does so, an acceleration of bubble ascent due to the decreased viscous resistance facing bubbles inside filaments and yielding enhanced mass flux of mafic melt into felsic melt via entrainment. In magma mixing events involving melts of high volatile content, bubbles may be an essential catalyst for magma mixing. <br><br> Moreover, the reduced viscosity contrast within filaments implies repeated replenishment of filaments with fresh end-member melt. As a result, complex compositional gradients and therefore diffusion systematics can be expected at the filament-host melt interface, due to the repetitive nature of the process. However, previously magmatic filaments were tacitly assumed to be of single-pulse origin. Consequently, the potential for multi-pulse filaments has to be considered in outcrop analyses. As compositional profiles alone may remain ambiguous for constraining the origin of filaments, and as 3-D visual evidence demonstrates that filaments may have experienced multiple bubbles passages even when featuring standard diffusion gradients, therefore, the calculation of diffusive timescales may be inadequate for constraining timescales in cases where bubbles have played an essential role in magma mixing. Data analysis employing concentration variance relaxation in natural samples can distinguish conventional single-pulse filaments from advection via multiple bubble ascent advection in natural samples, raising the prospect of yet another powerful application of this novel petrological tool. © 2015 Author(s). 2015 English 18699510 10.5194/se-6-1007-2015 Solid Earth 6 Copernicus GmbH 1007-1023 Dept. of Earth and Environmental Sciences, Ludwig-Maximilians-Universität München, Münich, 80333, Germany; GEOVOL, Universidad de Las Palmas de Gran Canaria, Las Palmas de Gran Canaria, 35017, Spain; Department of Physics and Geology, University of Perugia, Perugia, 06100, Italy; Research School of Earth Sciences, Australian National University, Canberra, ACT 0200, Australia; Earth Ocean and Ecological Sciences, University of Liverpool, Liverpool, L69 3GP, United Kingdom 3 Advection; Basalt; Cylinders (shapes); Glass; Mixing; Silicates; Viscosity, Compositional gradients; Diffusion gradients; Magmatic temperatures; Orders of magnitude; Reduced viscosity; Rheological modelling; Viscous resistance; Volatile contents, Computerized tomography, advection; bubble; chemical alteration; chemical composition; entrainment; experimental study; igneous geochemistry; magma assimilation; mixing; rhyolite; silicate melt https://www.scopus.com/inward/record.uri?eid=2-s2.0-84940029526&doi=10.5194%2fse-6-1007-2015&partnerID=40&md5=b2e077761c9c6882732b703f784e33dd cited By 15 S. Wiesmaier D. Morgavi C.J. Renggli D. Perugini C.P. De Campos K.-U. Hess W. Ertel-Ingrisch Y. Lavallée D.B. Dingwell article Wang201568 Stable carbon isotopic composition of organic matter (δ13Corg) and compound-specific δ13C values of biomarkers from 15 lacustrine source rocks were analyzed to identify the original paleoenvironment and source organisms. The δ13C values of hopanes (δ13Chop) ranged from -68.7‰ to -32‰ and exhibit strongly 13C-depleted values in the lower part of Member 1 of the Nenjiang Formation (K2n1, up to -68.7‰), suggesting an origin from predominantly methanotrophic bacteria. 13C-enriched δ13CGa values and significantly 13C-depleted δ13Chop in K2n1, which coincide with water stratification and an intermittent anoxic photic zone, represents a shallow chemocline. The presence of an intermittent anoxic photic zone, which means that the anoxia expanded into the euphotic zone, is beneficial for OM preservation and results in high values of TOC and HI in this section. However, the absence of gammacerane and 13C-enrichment of δ13Chop in Member 2 of Nenjiang Formation (K2n2) reflect a deeper chemocline, corresponding to relatively oxidizing conditions and low values of TOC and HI. Moreover, the negative correlation of TOC vs δ13Corg and HI vs δ13Corg reflects the control of OM formation by sedimentary environments rather than productivity in the water column. Thus, the depth of the chemocline not only controls the abundance of OM but also affects the development of the microbial community, such as chemoautotrophic bacteria in the deep chemocline and chemoautotrophic and methanotrophic bacteria in the shallow chemocline. Moreover, δ13CGa and δ13C values for 4-methyl steranes are related to water salinity, with a higher salinity accompanied by 13C-enrichment in gammacerane and 4-methyl steranes. © 2015 Elsevier Ltd. 2015 English 01466380 10.1016/j.orggeochem.2015.07.011 Organic Geochemistry 87 Elsevier Ltd 68-77 State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, 510640, China; University of Chinese Academy of Sciences, Beijing, 100049, China Bacteria; Gallium; Isotopes, Carbon isotopes; Chemocline; Nenjiang Formation; Paleo-environment; Upper Cretaceous, Biomarkers, anoxic conditions; carbon isotope; chemoautotrophy; Cretaceous; economic geology; hydrocarbon; isotopic composition; lacustrine environment; microbial community; paleoenvironment; source rock; stratification, China; Nen Basin; Songliao Basin https://www.scopus.com/inward/record.uri?eid=2-s2.0-84939622486&doi=10.1016%2fj.orggeochem.2015.07.011&partnerID=40&md5=feeeaf00d60dee2263f6fa972af6d18b cited By 16 L. Wang Z. Song X. Cao Y. Li article wenlong2015drilling 2015 石油钻采工艺 37 石油钻采工艺 32-35 3 ZHENG Wenlong Wu Xiaoming ZHU Yongyi Wang Wenshi ZHANG Linsheng Xu Jie article Prevedel20151537 Downhole sensors of different types and in various environments provide substantial benefit to signal quality. They also add the depth dimension to measurements performed at the Earths’ surface. Sensor types that particularly benefit from downhole installation due to the absence of near-surface noise include piezometers, seismometers, strainmeters, thermometers, and tiltmeters. Likewise, geochemical and environmental measurements in a borehole help eliminate near-surface weathering and cultural effects. Installations from a few hundred meter deep to a few kilometer deep dramatically reduce surface noise levels—the latter noticeably also reduces the hypocentral distance for shallow microearthquakes. The laying out of a borehole network is always a compromise of local boundary conditions and the involved drilling costs. The installation depth and procedure for a long-term downhole observatory can range from time limited installations, with a retrieval option, to permanently cemented sensors. Permanently cemented sensors have proven to be long-term stable with non-deteriorating coupling and borehole integrity. However, each type needs to be carefully selected and planned according to the research aims. A convenient case study is provided by a new installation of downhole seismometers along the shoreline of the eastern Marmara Sea in Turkey. These stations are being integrated into the regional net for monitoring the North Anatolian Fault Zone. Here we discuss its design, installation, and first results. We conclude that, despite the logistical challenges and installation costs, the superior quality of downhole data puts this technique at the forefront of applied and fundamental research. © 2015, The Author(s). 2015 English 14373254 10.1007/s00531-015-1147-5 International Journal of Earth Sciences 104 Springer Verlag 1537-1547 Helmholtz-Centre Potsdam GFZ German Centre for Geosciences, Telegrafenberg, Potsdam, 14473, Germany; Department of Earth Sciences, Free University Berlin, Malteser Strasse 74-100, Berlin, 12249, Germany; AFAD, Disaster and Emergency Management Presidency, Ankara, Turkey; IESE, University of Aukland, Aukland, New Zealand; TÜBITAK Marmara Research Center, Gebze, Turkey 6 earthquake hypocenter; earthquake mechanism; fault zone; microearthquake; North Anatolian Fault; piezometer; seismic noise; seismograph, Sea of Marmara; Turkey https://www.scopus.com/inward/record.uri?eid=2-s2.0-84940954063&doi=10.1007%2fs00531-015-1147-5&partnerID=40&md5=f3429336fb115bd9d5a14f7e0d10c2d3 cited By 12 B. Prevedel F. Bulut M. Bohnhoff C. Raub R.F. Kartal F. Alver P.E. Malin article Qiu20151185 2015 English 00368075 10.1126/science.348.6240.1185 Science 348 American Association for the Advancement of Science 1185 Beijing, China 6240 biostratigraphy; climate variation; dinosaur; fossil record; Jurassic; paleoenvironment; skeleton; taphonomy, biota; climate; Cretaceous; dinosaur; geological time; greenhouse effect; Jurassic; lake sediment; Maastrichtian; mass extinction; nonhuman; Paleocene; priority journal; Short Survey; temperature; animal; China; climate; greenhouse effect; lake; sediment; species extinction; temperature, Dinosauria, Animals; China; Climate; Dinosaurs; Extinction, Biological; Geologic Sediments; Global Warming; Greenhouse Effect; Lakes; Temperature https://www.scopus.com/inward/record.uri?eid=2-s2.0-84936103189&doi=10.1126%2fscience.348.6240.1185&partnerID=40&md5=262dee2ca42f51bc1469c9da6dca3b07 cited By 0 J. Qiu article Recasens2015309 Southern South America is a key site to study climate variability in the Southern Hemisphere, allowing for a wide variety of climatic archives. Recently, several investigations using lacustrine sediments have provided an enormous amount of information to reconstruct past environmental changes. In the framework of the Potrok Aike Maar Lake Sediment Archive Drilling Project (PASADO) more than 500. m of sediment cores were retrieved from the center of this lake.This contribution is centered in the diatom record of a core covering over the last 50. cal. ka BP. Nine statistically significant zones were determined based on changes in the assemblages of more than 200 species of diatoms, showing changes in productivity throughout time. Although it appears that the presence of mass waste events may have triggered some peaks in productivity, large fluctuations in diatom abundance and changes in species assemblages coincide with distinctive Antarctic warm events, A2 and A1, described for Antarctic ice cores at around 44.5 and 38.5 kyr BP respectively (Blunier and Brook, 2001). Furthermore, a smaller diatom peak may account for the A3 event compatible with a new OSL-based chronological model. Up to now they have only been described for Antarctica, but the fact that these events are recorded in southern Patagonia indicates their magnitude and importance for climate in the Southern Hemisphere. © 2014 Elsevier B.V. Article 2015 10.1016/j.palaeo.2014.09.021 Palaeogeography, Palaeoclimatology, Palaeoecology 417 309 – 319 Argentina; Laguna Potrok Aike; Patagonia; Santa Cruz [Argentina]; Bacillariophyta; bioindicator; climate variation; diatom; hydrological change; lacustrine deposit; maar; paleoclimate; Pleistocene; Southern Hemisphere https://www.scopus.com/inward/record.uri?eid=2-s2.0-84918575207&doi=10.1016%2fj.palaeo.2014.09.021&partnerID=40&md5=2834f79b66f176a216063b62da424993 Cited by: 20 Cristina Recasens Daniel Ariztegui Nora I. Maidana Bernd Zolitschka article Gao2015469 Sedimentary and diagenetic processes control the distribution of clay minerals in sedimentary basins, although these processes have seldom been studied continuously in continental sedimentary basins. The Songliao Basin, northeast China, is a large continental, petroleum-bearing basin, and provides a unique study site to understand the sedimentary and diagenetic processes that influence clay assemblages. In this paper, the clay mineralogy of a 2500 m-thick Late Cretaceous (late Turonian to Maastrichtian) terrestrial sedimentary succession (SK-1s and SK-1n cores), retrieved by the International Continental Scientific Drilling Program in the Songliao Basin, was examined. The objective was to determine the diagenetic and paleoenvironmental variations that controlled the formation of clay mineral assemblages, and to determine the thermal and paleoenvironmental evolution of the basin. The results from both cores show that illite is ubiquitous through the succession, smectite is frequently encountered in the upper strata, and ordered mixed-layer illite-smectite (I-S), chlorite, and kaolinite are abundant in the lower strata. Burial diagenesis is the primary control on the observed decrease of smectite and increasing illite, I-S, and chlorite with depth. Observations of clay-mineral diagenesis are used to reconstruct the paleotemperatures and maximum burial depths to which the sediments were subjected. The lowermost sediments could have reached a maximum burial of ~1000 m deeper than today and temperatures ~50ºC higher than today in the latest Cretaceous. The transition of smectite to I-S in the SK-1 cores and the inferred paleotemperatures provide new constraints for basin modeling of oil maturation at elevated temperatures in the Songliao Basin. Authigenic kaolinite and smectite are enriched in sandstones with respect to the coeval mudstones from the SK-1n core, as a result of early diagenesis with the participation of primary aluminosilicates and pore fluids. In the upper part of both SK-1 cores, variations in smectite and illite were controlled primarily by paleoenvironmental changes. Increases in smectite and decreases in illite from the late Campanian to Maastrichtian are interpreted as resulting from increasing humidity, a conclusion consistent with previous paleoenvironmental interpretations. © 2015, Clays and Clay Minerals. All rights reserved. 2015 English 00098604 10.1346/CCMN.2015.0630605 Clays and Clay Minerals 63 Clay Minerals Society 469-484 State Key Laboratory of Biogeology and Environmental Geology, School of Earth Sciences and Resources, China University of Geosciences (Beijing), Beijing, 100083, China; State Key Laboratory of Marine Geology, Tongji University, Shanghai, 200092, China; Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI 48109, United States; Department of Earth System Science, Stanford University, Stanford, CA 94305-4216, United States 6 Kaolinite; Minerals; Petroleum deposits; Process control; Sedimentology; Settling tanks, China; Diagenesis; Late cretaceous; Paleo-environment; Songliao basin; Thermal evolution, Clay minerals, aluminosilicate; Campanian; diagenesis; kaolinite; Maastrichtian; paleoenvironment; sedimentary basin; smectite, China; Songliao Basin https://www.scopus.com/inward/record.uri?eid=2-s2.0-84959499216&doi=10.1346%2fCCMN.2015.0630605&partnerID=40&md5=79d1b47a6a2c7e4624db5fe652d12843 cited By 16 Y. Gao C. Wang Z. Liu X. Du D.E. Ibarra article Ickrath20152120 We investigate spatiotemporal variations of the crustal stress field orientation along the rupture zones of the 1999 August Izmit Mw 7.4 and November Düzce Mw 7.1 earthquakes at the North Anatolian Fault zone (NAFZ) in NW Turkey. Our primary focus is to elaborate on the relation between the state of the crustal stress field and distinct seismotectonic features as well as variations of coseismic slip within the seismogenic layer of the crust. To achieve this, we compile an extensive data base of hypocentres and first-motion polarities including a newly derived local hypocentre catalogue extending from 2 yr prior (1997) to 2 yr after (2001) the Izmit and Düzce main shocks. This combined data set allows studying spatial and temporal variations of stress field orientation along distinct fault segments for the pre- and post-seimic phase of the two large earthquakes in detail. Furthermore, the occurrence of two M &gt; 7 earthquakes in rapid succession gives the unique opportunity to analyse the 87-d-long 'inter-seismic phase' between them. We use the MOTSI (first MOTion polarity Stress Inversion) procedure directly inverting first-motion polarities to study the stress field evolution of nine distinct segments. In particular, this allows to determine the stress tensor also for the pre- and post-seismic phases when no stable single-event focal mechanisms can be determined. We observe significantly different stress field orientations along the combined 200-km-long rupture in accordance with lateral variations of coseismic slip and seismotectonic setting. Distinct vertical linear segments of the NAFZ show either pure-strike slip behaviour or transtensional and normal faulting if located near pull-apart basins. Pull-apart structures such as the Akyazi and Düzce basins show a predominant normal faulting behaviour along the NAFZ and reflect clearly different characteristic from neighbouring strike-slip segments. Substantial lateral stress field heterogeneity following the two main shocks is observed that declines with time towards the post-seismic period that rather reflects the regional right-lateral strike-slip stress field. © The Authors 2015. Published by Oxford University Press on behalf of The Royal Astronomical Society. All rights reserved. 2015 English 0956540X 10.1093/gji/ggv273 Geophysical Journal International 202 Oxford University Press 2120-2132 Helmholtz Centre Potsdam GFZ German Research Centre for Geosciences, Section 3.2: Geomechanics and Rheology, Telegrafenberg, Potsdam, Germany; Free University Berlin, Department of Earth Sciences, Malteser Strasse 74-100, Berlin, D-12249, Germany; AFAMResearch Center, IstanbulAydinUniversity, Istanbul, 34295, Turkey 3 Earthquake effects; Earthquakes; Faulting; Geophysics; Seismology; Stresses; Strike-slip faults, Earthquake dynamics; Earthquake source observations; North Anatolian Fault Zone; Seismicity and tectonics; Seismotectonic settings; Spatial and temporal variation; Spatio-temporal variation; Stress-field orientation, Fault slips, coseismic process; earthquake catalogue; earthquake rupture; focal mechanism; inverse problem; Kocaeli earthquake 1999; seismic data; seismic source; seismicity; spatiotemporal analysis; stress field; tectonics, Anatolia; Turkey https://www.scopus.com/inward/record.uri?eid=2-s2.0-84940093600&doi=10.1093%2fgji%2fggv273&partnerID=40&md5=e76b0dccf85e559e1fa20ceefe00487f cited By 14 M. Ickrath M. Bohnhoff G. Dresen P. Martínez-Garzón F. Bulut G. Kwiatek O. Germer article Vogel2015359 Lake Towuti (2.5°S, 121.5°E) is a long-lived, tectonic lake located on the Island of Sulawesi, Indonesia, and in the center of the Indo-Pacific warm pool (IPWP). Lake Towuti is connected with upstream lakes Matano and Mahalona through the Mahalona River, which constitutes the largest inlet to the lake. The Mahalona River Delta is prograding into Lake Towuti’s deep northern basin thus exerting significant control on depositional processes in the basin. We combine high-resolution seismic reflection and sedimentological datasets from a 19.8-m-long sediment piston core from the distal edge of this delta to characterize fluctuations in deltaic sedimentation during the past ~29 kyr BP and their relation to climatic change. Our datasets reveal that, in the present, sedimentation is strongly influenced by deposition of laterally transported sediments sourced from the Mahalona River Delta. Variations in the amount of laterally transported sediments, as expressed by coarse fraction amounts in pelagic muds and turbidite recurrence rates and cumulative thicknesses, are primarily a function of lake-level induced delta slope instability and delta progradation into the basin. We infer lowest lake-levels between ~29 and 16, a gradual lake level rise between ~16 and 11, and high lake-levels between ~11 and 0 kyr BP. Periods of highest turbidite deposition, ~26 to 24 and ~18 to 16 kyr BP coincide with Heinrich events 2 and 1, respectively. Our lake-level reconstruction therefore supports previous observations based on geochemical hydroclimate proxies of a very dry last glacial and a wet Holocene in the region, and provides new evidence of millennial-scale variations in moisture balance in the IPWP. © 2015, Springer Science+Business Media Dordrecht. Article 2015 English 09212728 10.1007/s10933-015-9857-z Journal of Paleolimnology 54 Kluwer Academic Publishers 359 – 377 4 Greater Sunda Islands; Lake Mahalona; Lake Matano; Lake Towuti; Malili Lakes; South Sulawesi; Sulawesi; Sulawesi; Sunda Isles; climate change; deltaic sedimentation; depositional environment; Heinrich event; Holocene; lacustrine deposit; Last Glacial; pool; reconstruction; sedimentology; turbidity https://www.scopus.com/inward/record.uri?eid=2-s2.0-84945448673&doi=10.1007%2fs10933-015-9857-z&partnerID=40&md5=eef60ceaf1d31a38b9457d2a5d449f11 Cited by: 25; All Open Access, Green Open Access James M. Russell Sri Yudawati Cahyarini Satria Bijaksana Nigel Wattrus Janet Rethemeyer article Torfstein2015235 Sediment cores recovered by the Dead Sea Deep Drilling Project (DSDDP) from the deepest basin of the hypersaline, terminal Dead Sea (lake floor at ~725 m below mean sea level) reveal the detailed climate history of the lake's watershed during the last interglacial period (Marine Isotope Stage 5; MIS5). The results document both a more intense aridity during MIS5 than during the Holocene, and the moderating impacts derived from the intense MIS5e African Monsoon. Early MIS5e (~133-128 ka) was dominated by hyperarid conditions in the Eastern Mediterranean-Levant, indicated by thick halite deposition triggered by a lake-level drop. Halite deposition was interrupted however, during the MIS5e peak (~128-122 ka) by sequences of flood deposits, which are coeval with the timing of the intense precession-forced African monsoon that generated Mediterranean sapropel S5. A subsequent weakening of this humidity source triggered extreme aridity in the Dead Sea watershed and resulting in the biggest known lake level drawdown in its history, reflected by the deposition of thick salt layers, and a capping pebble layer corresponding to a hiatus at ~116-110 ka. The DSDDP core provides the first evidence for a direct association of the African monsoon with mid subtropical latitude climate systems effecting the Dead Sea watershed. Combined with coeval deposition of Arabia and southern Negev speleothems, Arava travertines, and calcification of Red Sea corals, the evidence points to a climatically wet corridor that could have facilitated homo sapiens migration "out of Africa" during the MIS5e peak. The hyperaridity documented during MIS5e may provide an important analogue for future warming of arid regions of the Eastern Mediterranean-Levant. © 2014 Elsevier B.V.All rights reserved. 2015 English 0012821X 10.1016/j.epsl.2014.12.013 Earth and Planetary Science Letters 412 Elsevier 235-244 Lamont-Doherty Earth Observatory of Columbia University, 61 Rt. 9W, Palisades, NY 10964, United States; Institute of Earth Sciences, Hebrew University of Jerusalem, Jerusalem, 91904, Israel; Interuniversity Institute of Marine Sciences, Eilat, 88103, Israel; Department of Earth and Environmental Sciences, Columbia University, 61 Rt. 9W, Palisades, NY 10964, United States; ETH Zürich, Geologisches Institut, NO G 51.1, Sonneggstrasse 5, Zürich, 8092, Switzerland; Geological Survey of Israel, 30 Malkhe Israel Street, Jerusalem, 95501, Israel Arid regions; Atmospheric thermodynamics; Biomineralization; Deposition; Glacial geology; Isotopes; Lakes; Sea level; Seawater; Watersheds, African monsoons; Dead sea; Last interglacial; Levant; Paleoclimates; Sapropel, Chloride minerals, aridity; deposition; drawdown; flood deposit; Holocene; humidity; Last Interglacial; monsoon; paleoclimate; sapropel, Dead Sea; Levant; Mediterranean Region; Mediterranean Sea; Mediterranean Sea (East), Anthozoa; Homo sapiens https://www.scopus.com/inward/record.uri?eid=2-s2.0-84920911815&doi=10.1016%2fj.epsl.2014.12.013&partnerID=40&md5=ab516780fc03f928c45a8f02b7929ef1 cited By 95 A. Torfstein S.L. Goldstein Y. Kushnir Y. Enzel G. Haug M. Stein article Baumgarten20151639 A deep drilling campaign was performed at Lake Van (Turkey) to enhance the understanding of the paleoenvironmental conditions of the Middle East. Cores were collected, and the sediments are mainly composed of clayey silts and tephra deposits. Spectral gamma ray data were acquired (0–210 m below lake floor), and the uranium data were used for cyclostratigraphic studies to estimate the sedimentation rates and the time of deposition. Detection and analysis of climate cycles require continuous sedimentation and cannot be applied to these sediments which include numerous tephra layers. Therefore, these layers were removed, and a synthetic log was created (cumulative thickness of the tephra ≈50 m; remaining lacustrine sediments ≈160 m). High amplitudes were detected and correlated to Milanković cycles. Their evolution was analyzed using the sliding window technique. The sedimentation rates varied from 22 to 33 cm/ka in the upper section. The sediments between the lake floor and a depth of 210 m were deposited over a period of 587 ka. Our results agree with core interpretations (e.g., correlation of total organic carbon with marine isotope stages) which suggest a time span of deposition of 600 ka. High-frequency cycles were detected and correlated with interstadials from the North Greenland δ18O record for the past 75 ka. The two datasets agreed closely. We conclude that climate signals, even on sub-Milanković scale, are imprinted in uranium of these sediments, and cyclostratigraphic methods are applicable if event layers are subtracted from the sediment record. © 2014, The Author(s). 2015 English 14373254 10.1007/s00531-014-1082-x International Journal of Earth Sciences 104 Springer Verlag 1639-1654 Leibniz Institute for Applied Geophysics (LIAG), Stilleweg 2, Hannover, 30655, Germany 6 cyclostratigraphy; lacustrine deposit; logging (geophysics); Milankovitch cycle; paleoclimate; paleoenvironment; Quaternary; sediment core; sedimentation rate; tephra; uranium, Arctic; Greenland; Lake Van; Middle East; Turkey https://www.scopus.com/inward/record.uri?eid=2-s2.0-84940957014&doi=10.1007%2fs00531-014-1082-x&partnerID=40&md5=a3a685bbd079c0b97203db27c6d4872a cited By 12 H. Baumgarten T. Wonik article Premović2015721 Remarkably high arsenic (As) contents have been reported in numerous Cretaceous-Paleogene boundary (KPB) clays worldwide including those from Spain (at Caravaca and Agost) and New (N.) Zealand (at Woodside Creek). Two interpretations have been offered to explain this anomaly. The first one suggests that this As was generated by the combustion of fossil fuels (such as crude oil, coal or oil shales) near the Chicxulub impact site and the second interpretation proposes the post-impact combustion of the global biomass at the KPB. Both types of combustion were presumably triggered by the Chicxulub impactor. This report shows that the estimated surface densities of As in Spain and N. Zealand strongly contradict the fossil fuel hydrocarbons/biomass hypotheses. In addition, we also show that previously reported global abundances of As at KPB are greatly overestimated. The high abundances of iron (Fe) in the ejecta layers from Spain and N. Zealand lead us to a working hypothesis that a major fraction of their anomalous As was adsorbed from seawater by the Fe-oxides. These oxides were mainly derived of Fe from the vaporized carbonaceous chondrite impactor. These were originally deposited on the local (topographically high) oxic soils in Spain and N. Zealand and then laterally transported to the KPB sites by the impactinduced surface waters. © 2015 Pavle I. Premović 2015. 2015 10.1515/geo-2015-0052 Open Geosciences 7 721-731 Laboratory for Geochemistry, Cosmochemistry and Astrochemistry, University of Niš, P.O. Box 224, Nis, 18000, Serbia 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84949201109&doi=10.1515%2fgeo-2015-0052&partnerID=40&md5=f0bad5d1207df62b48203c9837fa9623 cited By 2 P.I. Premović article lorenz_h._cosc-1_2015 2015 https://doi.org/10.1594/GFZ.SDDB.ICDP.5054.2015 GFZ German Research Centre for Geosciences https://doi.org/10.5880/ICDP.5054.002 00000 H. Lorenz J.-E. Rosberg Christopher Juhlin L. Bjelm B.S.G. Almqvist T. Berthet R. Conze D. G. Gee I. Klonowska C. Pascal K. Pedersen N. Roberts C.F. Tsang article lorenz_cosc-1_2015 2015 may 1816-3459 10.5194/sd-19-1-2015 Scientific Drilling 19 1--11 http://www.sci-dril.net/19/1/2015/ 00000 Henning Lorenz J.-E. Rosberg C. Juhlin L. Bjelm B. S. G. Almqvist T. Berthet R. Conze D. G. Gee I. Klonowska C. Pascal K. Pedersen N. M. W. Roberts C.-F. Tsang article Lyons201515568 The transport of moisture in the tropics is a critical process for the global energy budget and on geologic timescales, has markedly influenced continental landscapes, migratory pathways, and biological evolution. Here we present a continuous, first-of-its-kind 1.3-My record of continental hydroclimate and lake-level variability derived from drill core data from Lake Malawi, East Africa (9-15° S). Over the Quaternary, we observe dramatic shifts in effective moisture, resulting in large-scale changes in one of the world's largest lakes and most diverse freshwater ecosystems. Results show evidence for 24 lake level drops of more than 200 m during the Late Quaternary, including 15 lowstands when water levels were more than 400 m lower than modern. A dramatic shift is observed at the Mid-Pleistocene Transition (MPT), consistent with far-field climate forcing, which separates vastly different hydroclimate regimes before and after ∼800,000 years ago. Before 800 ka, lake levels were lower, indicating a climate drier than today, and water levels changed frequently. Following the MPT high-amplitude lake level variations dominate the record. From 800 to 100 ka, a deep, often overfilled lake occupied the basin, indicating a wetter climate, but these highstands were interrupted by prolonged intervals of extreme drought. Periods of high lake level are observed during times of high eccentricity. The extreme hydroclimate variability exerted a profound influence on the Lake Malawi endemic cichlid fish species flock; the geographically extensive habitat reconfiguration provided novel ecological opportunities, enabling new populations to differentiate rapidly to distinct species. 2015 English 00278424 10.1073/pnas.1512864112 Proceedings of the National Academy of Sciences of the United States of America 112 National Academy of Sciences 15568-15573 Department of Earth Sciences, Syracuse University, Syracuse, NY 13244, United States; Department of Geosciences, University of Arizona, Tucson, AZ 85721, United States; Graduate School of Oceanography, University of Rhode Island, Narragansett, RI 02882, United States; Large Lakes Observatory, Department of Earth and Environmental Sciences, University of Minnesota, Duluth, MN 55812, United States; Institute at Brown for the Study of the Environment and Society, Brown University, Providence, RI 02912, United States; Berkeley Geochronology Center, Berkeley, CA 94709, United States; Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ 85721, United States; Department of Earth and Environmental Sciences, University of Kentucky, Lexington, KY 40506, United States; Chevron Corporation, Houston, TX 77002, United States; BP L48, Onshore, Houston, TX 77079, United States 51 water, Article; atmospheric moisture; biodiversity; catchment; cichlid; climate change; clinical effectiveness; East African; freshwater environment; hydroclimate; lake; Middle Pleistocene; molecular evolution; nonhuman; paleoclimate; priority journal; species diversity; tropic climate; Africa; animal; climate; ecosystem; evolution; history; paleontology; time factor, Africa, Eastern; Animals; Biodiversity; Biological Evolution; Cichlids; Climate; Climate Change; Ecosystem; History, Ancient; Lakes; Paleontology; Time Factors https://www.scopus.com/inward/record.uri?eid=2-s2.0-84952684824&doi=10.1073%2fpnas.1512864112&partnerID=40&md5=13f4bc8c908d5027581c476536c082d5 cited By 86 R.P. Lyons C.A. Scholz A.S. Cohen J.W. King E.T. Brown S.J. Ivory T.C. Johnson A.L. Deino P.N. Reinthal M.M. McGlue M.W. Blome article Bradbury20151053 We examine the fine-scale variations in mineralogical composition, geochemical alteration, and texture of the fault-related rocks from the Phase 3 whole-rock core sampled between 3,187.4 and 3,301.4 m measured depth within the San Andreas Fault Observatory at Depth (SAFOD) borehole near Parkfield, California. This work provides insight into the physical and chemical properties, structural architecture, and fluid-rock interactions associated with the actively deforming traces of the San Andreas Fault zone at depth. Exhumed outcrops within the SAF system comprised of serpentinite-bearing protolith are examined for comparison at San Simeon, Goat Rock State Park, and Nelson Creek, California. In the Phase 3 SAFOD drillcore samples, the fault-related rocks consist of multiple juxtaposed lenses of sheared, foliated siltstone and shale with block-in-matrix fabric, black cataclasite to ultracataclasite, and sheared serpentinite-bearing, finely foliated fault gouge. Meters-wide zones of sheared rock and fault gouge correlate to the sites of active borehole casing deformation and are characterized by scaly clay fabric with multiple discrete slip surfaces or anastomosing shear zones that surround conglobulated or rounded clasts of compacted clay and/or serpentinite. The fine gouge matrix is composed of Mg-rich clays and serpentine minerals (saponite ± palygorskite, and lizardite ± chrysotile). Whole-rock geochemistry data show increases in Fe-, Mg-, Ni-, and Cr-oxides and hydroxides, Fe-sulfides, and C-rich material, with a total organic content of >1 % locally in the fault-related rocks. The faults sampled in the field are composed of meters-thick zones of cohesive to non-cohesive, serpentinite-bearing foliated clay gouge and black fine-grained fault rock derived from sheared Franciscan Formation or serpentinized Coast Range Ophiolite. X-ray diffraction of outcrop samples shows that the foliated clay gouge is composed primarily of saponite and serpentinite, with localized increases in Ni- and Cr-oxides and C-rich material over several meters. Mesoscopic and microscopic textures and deformation mechanisms interpreted from the outcrop sites are remarkably similar to those observed in the SAFOD core. Micro-scale to meso-scale fabrics observed in the SAFOD core exhibit textural characteristics that are common in deformed serpentinites and are often attributed to aseismic deformation with episodic seismic slip. The mineralogy and whole-rock geochemistry results indicate that the fault zone experienced transient fluid–rock interactions with fluids of varying chemical composition, including evidence for highly reducing, hydrocarbon-bearing fluids. © 2014, Springer Basel. 2015 English 00334553 10.1007/s00024-014-0896-6 Pure and Applied Geophysics 172 Birkhauser Verlag AG 1053-1078 Geology Department, Utah State University, Logan, UT 84322-4505, United States 5 Deformation; Geochemistry; Kaolinite; Lithology; Minerals; Nickel; Oil bearing formations; Petroleum deposits; Serpentine; Silicate minerals; Strike-slip faults; Structural geology; Sulfide minerals; Textures; X ray diffraction, Coast range ophiolites; Fluid-rock interaction; Mineralogical compositions; Physical and chemical properties; Structural architecture; Textural characteristic; Total organic contents; Whole-rock geochemistries, Rocks, chemical composition; deformation mechanism; fault zone; hydrochemistry; mineralization; protolith; San Andreas Fault; saponite; serpentinite; water-rock interaction, California; Parkfield; San Simeon; United States, Capra hircus https://www.scopus.com/inward/record.uri?eid=2-s2.0-84926179721&doi=10.1007%2fs00024-014-0896-6&partnerID=40&md5=782699c2cf82c5ae243a0feaf235a9bc cited By 23 K.K. Bradbury C.R. Davis J.W. Shervais S.U. Janecke J.P. Evans article Duncan2015172 New evidence suggests that seismic waves from the Chicxulub meteorite impact doubled the eruption rate of lavas on the opposite side of the planet - a combination that led to the mass extinction at the end of the Cretaceous period. © 2015 Macmillan Publishers Limited. All rights reserved. 2015 10.1038/527172a Nature 527 172-173 College of Earth, Ocean and Atmospheric Sciences, Oregon State University, Corvallis, OR 97331, United States 7577 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84946898798&doi=10.1038%2f527172a&partnerID=40&md5=bdcd6237b27d0820738fa9ce9e548116 cited By 0 R. Duncan article Nickschick20152107 Strong, subcontinental mantle-dominated CO2 degassing occurs in the Hartoušov and Bublák mofette fields in the western Eger Rift. The combination of CO2 gas flux and soil gas measurements as well as gravity and geoelectric surveys provides insight into the surface and subsurface of this unique mofette area. CO2 soil gas and gas flux measurements reveal that large amounts of carbon dioxide are released via channels with diameters below 1 m. Carbon dioxide emissions of several tens and up to more than 100 kg day−1 are ejected via these small seeps. Measurements with small spacings are necessary to account for the point like, focused gas discharge in the lesser degassing surrounding. We estimate that between 23 and 97 tons of CO2 are released over an area of about 350,000 m2 each day in the Hartoušov mofette field. The application of widely used geostatistical tools leads to estimations of the CO2 discharge with very high standard deviations due to the strong positive skewness of the data distribution. Geophysical investigations via electrical resistivity tomography and gravity measurements were carried out over areas of strong seepage and reveal distinct anomalies in the subsurface below mofettes, indicating rock and sediment alterations and/or sediment transport by pressurised, ascending CO2 and water mobilised by it. This study reveals that the gas emanations only occur west of a morphological step which is related to a N–S-oriented fault zone, the Počatky-Plesná fault zone. The results of CO2 mapping and the geophysical studies can track the course of this fault zone in this area. Our results fit into a tectonic model in which the mofette fields are in the centres of two independent pull-apart basin-like structures. We hypothesise that the sinistral strike-slip movement of the Počatky-Plesná fault zone leads to a pull-apart basin-like opening, at which the strong, mantle-derived CO2 degassing occurs nowadays. Since the Hartoušov and Bublák mofette fields only illustrate examples along the N–S-striking Počatky-Plesná fault zone, its role and other N–S-striking faults’ roles of the Regensburg–Leipzig–Rostock zone for upper mantle degassing might have been underestimated previously. © 2015, Springer-Verlag Berlin Heidelberg. Article 2015 English 14373254 10.1007/s00531-014-1140-4 International Journal of Earth Sciences 104 Springer Verlag 2107 – 2129 8 Cheb Basin; Czech Republic; Karlovarsky; carbon dioxide; carbon emission; carbon flux; degassing; electrical method; electrical resistivity; gravity survey https://www.scopus.com/inward/record.uri?eid=2-s2.0-84945459789&doi=10.1007%2fs00531-014-1140-4&partnerID=40&md5=8fe19a5ebecd6c18d611e6aab81e8352 Cited by: 34 Tobias Nickschick Horst Kämpf Christina Flechsig Jan Mrlina Jens Heinicke article Schleicher201513 Clay minerals are increasingly recognised as important controls on the state and mechanical behaviour of fault systems in the upper crust. Samples retrieved by shallow drilling from two principal slip zones within the central Alpine Fault, South Island, New Zealand, offer an excellent opportunity to investigate clay formation and fluid-rock interaction in an active fault zone. Two shallow boreholes, DFDP-1A (100.6 m deep) and DFDP-1B (151.4 m) were drilled in Phase 1 of the Deep Fault Drilling Project (DFDP-1) in 2011. We provide a mineralogical and textural analysis of clays in fault gouge extracted from the Alpine Fault. Newly formed smectitic clays are observed solely in the narrow zones of fault gouge in drill core, indicating that localised mineral reactions are restricted to the fault zone. The weak preferred orientation of the clay minerals in the fault gouge indicates minimal strain-driven modification of rock fabrics. While limited in extent, our results support observations from surface outcrops and faults systems elsewhere regarding the key role of clays in fault zones and emphasise the need for future, deeper drilling into the Alpine Fault in order to understand correlative mineralogies and fabrics as a function of higher temperature and pressure conditions. © 2015 The Royal Society of New Zealand. 2015 English 00288306 10.1080/00288306.2014.979841 New Zealand Journal of Geology and Geophysics 58 Taylor and Francis Asia Pacific 13-21 Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI, United States; GNS Science, Lower Hutt, New Zealand; School of Geography, Environment and Earth Sciences, Victoria University of Wellington, Wellington, New Zealand; Department of Geology, University of Otago, Dunedin, New Zealand; Helmholtz-Zentrum Potsdam, Deutsches GeoForschungsZentrum, Telegrafenberg, Potsdam, 14473, Germany 1 active fault; borehole; clay mineral; fault gouge; fault zone; mineralogy; smectite; water-rock interaction, Alpine Fault Zone; New Zealand; South Island https://www.scopus.com/inward/record.uri?eid=2-s2.0-84924595592&doi=10.1080%2f00288306.2014.979841&partnerID=40&md5=39d21915ba9c83353a0f7bb43ed08e54 cited By 26 A.M. Schleicher R. Sutherland J. Townend V.G. Toy B.A. Van Der Pluijm article Weber2015253 We tested the use of visible to near-infrared (VNIR) reflectance spectroscopy to characterize the relative abundances of clay minerals in sediments from Lake Towuti, a large tectonic lake in Sulawesi, Indonesia. We measured VNIR spectra of lake and river sediments from Lake Towuti and its catchment to identify clay minerals, fit major VNIR absorption features with a modified Gaussian model to estimate relative abundances of these minerals, and compared these absorptions to the samples’ chemistry to test the utility of VNIR spectroscopy to characterize sediment compositional variations. We found that major absorptions are caused by vibrations of Al–OH in kaolinite (2.21 μm), Fe–OH in nontronite (2.29 μm), Mg–OH in saponite and serpentine (2.31 μm), and Mg–OH in serpentine (2.34 μm). This was confirmed with X-ray diffraction data. The correlations between absorption band areas for Fe–OH, Al–OH, and Mg–OH vibrations and Fe, Al and Mg concentrations, respectively, are statistically significant, varying between r = 0.51 and r = 0.90, and spatial variations in inferred clay mineralogy within the lake are consistent with variations in the geology of the catchment. We conclude that VNIR spectroscopy is an effective way to characterize the clay mineralogy of lake sediments, and can be used to investigate changes in mineral inputs to lake deposits. © 2015, Springer Science+Business Media Dordrecht. Article 2015 English 09212728 10.1007/s10933-015-9844-4 Journal of Paleolimnology 54 Kluwer Academic Publishers 253 – 261 2-3 Greater Sunda Islands; Lake Towuti; Malili Lakes; South Sulawesi; Sulawesi; Sulawesi; Sunda Isles; clay mineral; fluvial deposit; lacustrine deposit; paleolimnology; relative abundance; spatial variation; spectroscopy https://www.scopus.com/inward/record.uri?eid=2-s2.0-84941416465&doi=10.1007%2fs10933-015-9844-4&partnerID=40&md5=378488154e33dc6021afb8c421f0f478 Cited by: 6 Andrea K. Weber James M. Russell Timothy A. Goudge Mark R. Salvatore John F. Mustard Satria Bijaksana article Cox2015216 Thermal springs in the Southern Alps, New Zealand, originate through penetration of fluids into a thermal anomaly generated by rapid uplift and exhumation on the Alpine Fault. Copland hot spring (43.629S, 169.946E) is one of the most vigorously flowing, hottest of the springs, discharging strongly effervescent CO2-rich 56-58°C water at 6 ± 1 l sec-1. Shaking from the Mw7.8 Dusky Sound (Fiordland) 2009 and Mw7.1 Darfield (Canterbury) 2010 earthquakes, 350 and 180 km from the spring, respectively, resulted in a characteristic approximately 1°C delayed cooling over 5 days. A decrease in conductivity and increase in pH were measured following the Mw7.1 Darfield earthquake. Earthquake-induced decreases in Cl, Li, B, Na, K, Sr and Ba concentrations and an increase in SO4 concentration reflect higher proportions of shallow-circulating meteoric fluid mixing in the subsurface. Shaking at amplitudes of approximately 0.5% g Peak Ground Acceleration (PGA) and/or 0.05-0.10 MPa dynamic stress influences Copland hot spring temperature, which did not respond during the Mw6.3 Christchurch 2011 aftershock or other minor earthquakes. Such thresholds should be exceeded every 1-10 years in the central Southern Alps. The characteristic cooling response at low shaking intensities (MM III-IV) and seismic energy densities (approximately 10-1 J m-3) from intermediate-field distances was independent of variations in spectral frequency, without the need for post-seismic recovery. Observed temperature and fluid chemistry responses are inferred to reflect subtle changes in the fracture permeability of schist mountains adjacent to the spring. Permanent 10-7-10-6 strains recorded by cGPS reflect opening or generation of fractures, allowing greater quantities of relatively cool near-surface groundwater to mix with upwelling hot water. Active deformation, tectonic and topographic stress in the Alpine Fault hanging wall, where orographic rainfall, uplift and erosion are extreme, make the Southern Alps hydrothermal system particularly susceptible to earthquake-induced transient permeability. © 2014 The Authors Geofluids Published by John Wiley & Sons Ltd. 2015 English 14688115 10.1111/gfl.12093 Geofluids 15 Blackwell Publishing Ltd 216-239 GNS Science, Dunedin, New Zealand; Ocean and Earth Science, National Oceanography Centre Southampton, University of Southampton, Southampton, United Kingdom; GNS Science, Lower Hutt, New Zealand; School of Surveying, University of Otago, Dunedin, New Zealand; School of Geography, Environment and Earth Sciences, Victoria University of Wellington, Wellington, New Zealand 1-2 earthquake; exhumation; fluid flow; geothermal system; hanging wall; hydrogeology; permeability; temperature anomaly; thermal spring; uplift, Alpine Fault Zone; New Zealand; South Island; Southern Alps https://www.scopus.com/inward/record.uri?eid=2-s2.0-84923130393&doi=10.1111%2fgfl.12093&partnerID=40&md5=87fefde6456c025a12a6bca860060517 cited By 60 S.C. Cox C.D. Menzies R. Sutherland P.H. Denys C. Chamberlain D.A.H. Teagle article melezhik2015carbonate Several deep drillholes were made in the Onega palaeobasin by the Fennoscandian Arctic Russia-Drilling Early Earth Project (FAR-DEEP) of the International Continental Scientific Drilling Program (ICDP). These provided fresh core material documenting the Lomagundi-Jatuli Isotopic Event (LJIE), its termination, and the start of the Shunga Event (SHE) of an enhanced accumulation of organic matter. The cored section represents the most complete known record of the end of the LJIE.The late phase of the LJIE, recorded in FAR-DEEP Core 11A, is represented by the upper part of the Tulomozero Formation (TF), a 300-m-thick unit composed of variegated dolostones, siltstones and shales. Accumulated under oxic conditions on a shallow-water carbonate platform, the TF hosts the earliest known thick formations of halite and massive anhydrite. Low-temperature greenschist facies metamorphism caused partial recrystallisation of the rocks; however, a primary carbonate phase, the dolomite, exhibits a negligible degree of post-depositional alteration of the carbon isotope system. The dataset of 46 bulk-carbonate analyses of carbon and oxygen isotopes yielded δ13Ccarb ranging between +6.8 and +11.8‰, and revealed a positive excursion from +8 to +11.8‰ followed by a decline to +8‰ towards the top of the 300-m-thick succession.The cored part of the overlying Zaonega Formation (ZF) recovered in holes 12AB and 13A is an 800-m-thick unit composed of mixed siliciclastic-carbonate facies with numerous mafic lava flows and tuff beds intruded by gabbro sills. The formation represents an unprecedented episode of enhanced accumulation of organic-rich rocks and preserves the earliest known supergiant, petrified oilfield, all typifying the SHE. The sedimentological, petrographic, geochemical and C- and O-isotopic study of over 800m of core throughout the ZF suggests that the initial carbonate deposition occurred in a lacustrine environment, then rapidly proceeding through a lagoonal setting to a rifted deepwater shelf, and finally to a carbonate platform. Both the deepwater shelf and the platformal settings are marked by organic-rich environments. The primary dolomite was potentially exposed to syn- and post-depositional hydrothermal/metasomatic alterations, organic matter diagenesis, metamorphic mineral reactions, CO2 degassing, and finally a low-temperature, post-metamorphic calcitisation resulting in overall large fluctuations of δ13Ccarb between -22 and +8‰. The dataset of over 413 bulk-carbonate analyses of carbon and oxygen isotopes, screened petrographically and geochemically against post-depositional alteration, revealed 28 least-altered samples within three stratigraphic intervals, suggesting multiple positive and negative δ13Ccarb excursions throughout over 1000m of stratigraphy. A shift from +5 to +9‰ followed by a drop to near zero values marks the lower part of the ZF. A δ13Ccarb decline from +8‰ to below zero in the middle and upper part of the ZF defines the end of the LJIE. A subsequent prominent negative excursion down to -6‰ does not show convincing isotopic evidence for influence of methanogenesis, and hence appears to be of primary depositional origin. An erratic positive excursion in the uppermost part of the drilled section indicates return of δ13Ccarb to a near normal marine value. © 2015 Elsevier B.V. 2015 English 00128252 10.1016/j.earscirev.2015.05.005 Earth-Science Reviews 147 Elsevier 65--98 Geological Survey of Norway, Postboks 6315 Slupen, Trondheim, NO-7491, Norway; Scottish Universities Environmental Research Centre, Rankine Avenue, East Kilbride, Scotland, G75 0QF, United Kingdom; University of Aberdeen, Department of Geology and Petroleum Geology, Meston Building, Scotland, AB24 3UE, United Kingdom bitumen; carbon isotope; carbonate platform; depositional environment; dolomite; lithostratigraphy; organic matter; Proterozoic; sediment core, Arkhangelsk [Russian Federation]; Fennoscandia; Onega Basin; Russian Federation https://www.scopus.com/inward/record.uri?eid=2-s2.0-84930225434&doi=10.1016%2fj.earscirev.2015.05.005&partnerID=40&md5=06df153c1676b4786b9faf481f77f453 cited By 26 Victor A Melezhik Anthony E Fallick Alexander T Brasier Aivo Lepland article sjoqvist_innovative_2015 2015 may 1816-3459 10.5194/sd-19-13-2015 Scientific Drilling 19 13--16 http://www.sci-dril.net/19/13/2015/ 00000 A. S. L. Sjöqvist M. Arthursson A. Lundström E. Calderón Estrada A. Inerfeldt H. Lorenz article Baumgarten20157453 Gamma ray (GR) fluctuations and potassium (K) values from downhole logging data obtained in the sediments of Lake Ohrid from 0 to 240 m below lake floor (b.l.f). correlate with fluctuations in δ18O values from the global benthic isotope stack LR04 (Lisiecki and Raymo, 2005). GR and K values are considered a reliable proxy to depict glacial-interglacial cycles, with high clastic input during cold and/or drier periods and high carbonate precipitation during warm and/or humid periods at Lake Ohrid. Spectral analysis was applied to investigate the climate signal and evolution over the length of the borehole. Linking downhole logging data with orbital cycles was used to estimate sedimentation rates and the effect of compaction was compensated for. Sedimentation rates increase on average by 14 % after decompaction of the sediment layers and the mean sedimentation rates shift from 45 cm kyr-1 between 0 and 110 m to 30 cm kyr-1 from 110 to 240 m b.l.f. Tuning of minima and maxima of gamma ray and potassium values versus LR04 extrema, in combination with eight independent tephrostratigraphical tie points, allows establishing of a robust age model for the downhole logging data over the past 630 kyr. © Author(s) 2015. Article 2015 English 17264170 10.5194/bg-12-7453-2015 Biogeosciences 12 Copernicus GmbH 7453 – 7465 Leibniz Institute for Applied Geophysics, Section Rock Physics and Borehole Geophysics, Hanover, Germany; University of Cologne, Institute for Geology and Mineralogy, Cologne, Germany; University of Pisa, Dipartimento di Scienze della Terra, Pisa, Italy; University of Bari Aldo Moro, Dipartimento di Scienze della Terra e Geoambientali, Bari, Italy; Instituto di Geologia Ambientale e Geoingegneria - CNR, Rome, Italy; Laboratoire des Sciences du Climat et de l'Environnement, IPSL, Laboratoire CEA/CNRS/UVSQ, Gif-Sur-Yvette, France 24 Lake Ohrid; age determination; benthos; carbonate; climate signal; cyclostratigraphy; gamma ray radiation; glacial-interglacial cycle; lacustrine deposit; oxygen isotope; potassium; precipitation (chemistry); sedimentation rate https://www.scopus.com/inward/record.uri?eid=2-s2.0-84951815976&doi=10.5194%2fbg-12-7453-2015&partnerID=40&md5=a9a30c4086f5223e94fa8aab53367b99 Cited by: 23; All Open Access, Gold Open Access, Green Open Access H. Baumgarten T. Wonik D.C. Tanner A. Francke B. Wagner G. Zanchetta R. Sulpizio B. Giaccio S. Nomade article Condon201517 2015 English 18168957 10.5194/sd-19-17-2015 Scientific Drilling 19 Copernicus GmbH 17-25 NERC Isotope Geoscience Facilities, British Geological Survey, Nottingham, United Kingdom; Instituto de Geociências, Universidade de São Paulo, São Paulo, Brazil; Department of Earth and Planetary Sciences, Washington UniversityWA, United States; Department of Earth and Planetary Sciences, McGill University, Montreal, Canada; Department of Geosciences, University of Bremen, Bremen, Germany; Department of Earth and Planetary Sciences, Harvard University, Cambridge, United States; Department of Earth and Environmental Sciences, University of St Andrews, St Andrews, United Kingdom; State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing, China Energy resources; Mechanical engineering, Neoproterozoic; Scientific drilling, Drilling https://www.scopus.com/inward/record.uri?eid=2-s2.0-84930403996&doi=10.5194%2fsd-19-17-2015&partnerID=40&md5=a64ef5596da10477bab5a1df8581307c cited By 5 D.J. Condon P. Boggiani D. Fike G.P. Halverson S. Kasemann A.H. Knoll F.A. Macdonald A.R. Prave M. Zhu article Pickarski20151491 Detailed analyses of the Lake Van pollen, Ca / K ratio, and stable oxygen isotope record allow the identification of millennial-scale vegetation and environmental changes in eastern Anatolia throughout the last glacial (∼ 111.5-11.7 ka BP). The climate of the last glacial was cold and dry, indicated by low arboreal pollen (AP) levels. The driest and coldest period corresponds to Marine Isotope Stage (MIS) 2 (∼ 28-14.5 ka BP), which was dominated by highest values of xerophytic steppe vegetation. <br><br> Our high-resolution multi-proxy record shows rapid expansions and contractions of tree populations that reflect variability in temperature and moisture availability. These rapid vegetation and environmental changes can be related to the stadial-interstadial pattern of Dansgaard-Oeschger (DO) events as recorded in the Greenland ice cores. Periods of reduced moisture availability were characterized by enhanced occurrence of xerophytic species and high terrigenous input from the Lake Van catchment area. Furthermore, the comparison with the marine realm reveals that the complex atmosphere-ocean interaction can be explained by the strength and position of the westerlies, which are responsible for the supply of humidity in eastern Anatolia. Influenced by the diverse topography of the Lake Van catchment, more pronounced DO interstadials (e.g., DO 19, 17-16, 14, 12 and 8) show the strongest expansion of temperate species within the last glacial. However, Heinrich events (HE), characterized by highest concentrations of ice-rafted debris (IRD) in marine sediments, cannot be separated from other DO stadials based on the vegetation composition in eastern Anatolia. In addition, this work is a first attempt to establish a continuous microscopic charcoal record for the last glacial in the Near East. It documents an immediate response to millennial-scale climate and environmental variability and enables us to shed light on the history of fire activity during the last glacial. © Author(s) 2015. 2015 English 18149324 10.5194/cp-11-1491-2015 Climate of the Past 11 Copernicus GmbH 1491-1505 University of Bonn, Steinmann Institute for Geology, Mineralogy, and Paleontology, Bonn, Germany; Ruhr-University Bochum, Sediment and Isotope Geology, Bochum, Germany; Tel Aviv University, Institute of Archaeology, Tel Aviv, Israel 11 carbon isotope; catchment; charcoal; climate variation; concentration (composition); Dansgaard-Oeschger cycle; GRIP; humidity; marine sediment; moisture; proxy climate record; stable isotope, Anatolia; Arctic; Greenland; Greenland Ice Sheet; Lake Van; Turkey https://www.scopus.com/inward/record.uri?eid=2-s2.0-84946546917&doi=10.5194%2fcp-11-1491-2015&partnerID=40&md5=74153686cc6d8ed336f638b857b576d9 cited By 41 N. Pickarski O. Kwiecien D. Langgut T. Litt book Haapala20151 Historically documented mining in Finland started in the 1530s when the area formed part of Sweden. The post of commissioner of mines was founded in 1638. The Swedish government activated mineral exploration in Finland in the seventeenth century and, during the Age of Utility, in the eighteenth century. Numerous small iron, copper, and lead occurrences were found, as well as the larger Orijärvi copper deposit. During 1809-1917 when Finland was a Grand Duchy within the Russian Empire, exploration was reorganized and strengthened. New, generally small iron deposits were discovered to supply iron works. Deposits found in the Pitkäranta area were mined for copper, tin, zinc, and iron. The Geological Survey of Finland was established in 1885. The large and rich Outokumpu copper deposit was discovered in 1910 as a result of scientific exploration by Otto Trüstedt of the Geological Survey. Since then, boulder tracing (later also till geochemistry), geophysical measurements, and diamond drilling have been the standard exploration methods. After Finland declared independence in 1917, mineral exploration was considered important for the development of domestic industry. In 1921 the Geological Survey discovered the nickel-copper ore field of Petsamo, and by the end of the 1930s, several other deposits, including the Otanmäki iron-titanium-vanadium deposit, were discovered. After the Second World War, the Geological Survey was reorganized and strengthened, and in the following decades it discovered numerous important ore deposits, including the Vihanti zinc-copper deposit (1951) and the Kemi chromium deposit (1960). The state-owned mining companies Outokumpu Oy and Rautaruukki Oy established their own exploration departments in the 1950s. Outokumpu Oy discovered the Kotalahti (1956), Vammala, and Kylmäkoski nickel-copper deposits, the Pyhäsalmi copper-zinc deposit (1958), the Vuonos (1965) and Kylylahti (1984) Outokumpu-type deposits, and several gold deposits. Otanmäki Oy/Rautaruukki Oy discovered several iron deposits in Lapland, as well as the large apatite-rich Sokli carbonatite complex. Rautaruukki Oy terminated their exploration activities in 1985 and Outokumpu Oy in 2003. Finnish private companies also carried out successful mineral exploration. After becoming a member of the European Union in 1995, the role of international mining and exploration companies has strongly increased in Finland, the main interest being in precious metal deposits. © 2015 Elsevier Inc. All rights reserved. Book chapter 2015 English 978-012410476-1; 978-012410438-9 10.1016/B978-0-12-410438-9.00001-7 Mineral Deposits of Finland Elsevier Inc. 1 – 38 Copper nickel deposits; Copper zinc deposits; Deposits; Diamond drilling; Economic geology; Geological surveys; History; Iron deposits; Military operations; Mineral exploration; Mineral industry; Natural resources exploration; Nickel; Nickel deposits; Ore deposits; Ores; Phosphate minerals; Tin deposits; Titanium deposits; Vanadium deposits; Domestic industries; Exploration company; Exploration methods; Finland; Geophysical measurements; Outokumpu Oy; Rautaruukki Oy; Scientific exploration; Gold deposits https://www.scopus.com/inward/record.uri?eid=2-s2.0-84939785457&doi=10.1016%2fB978-0-12-410438-9.00001-7&partnerID=40&md5=6300126fb0e1e454d46f3c82b01e80a0 Cited by: 8 I. Haapala H. Papunen article Lacey20151623 Lake Ohrid (Macedonia/Albania) is the oldest extant lake in Europe and exhibits an outstanding degree of endemic biodiversity. Here, we provide new high-resolution stable isotope and geochemical data from a 10 m core (Co1262) through the Late Glacial to Holocene and discuss past climate and lake hydrology (TIC, δ13Ccalcite, δ18Ocalcite) as well as the terrestrial and aquatic vegetation response to climate (TOC, TOC/N, δ13Corganic, Rock Eval pyrolysis). The data identifies 3 main zones: (1) the Late Glacial–Holocene transition represented by low TIC and TOC contents, (2) the early to mid-Holocene characterised by high TOC and increasing TOC/N and (3) the Late Holocene–Present which shows a marked decrease in TIC and TOC. In general, an overall trend of increasing δ18Ocalcite from 9 ka to present suggests progressive aridification through the Holocene, consistent with previous records from Lake Ohrid and the wider Mediterranean region. Several proxies show commensurate excursions that imply the impact of short-term climate oscillations, such as the 8.2 ka event and the Little Ice Age. This is the best-dated and highest resolution archive of past Late Glacial and Holocene climate from Lake Ohrid and confirms the overriding influence of the North Atlantic in the north-eastern Mediterranean. The data presented set the context for the International Continental scientific Drilling Program Scientific Collaboration On Past Speciation Conditions in Lake Ohrid project cores recovered in spring–summer 2013, potentially dating back into the Lower Pleistocene, and will act as a recent calibration to reconstruct climate and hydrology over the entire lake history. © 2014, Springer-Verlag Berlin Heidelberg. Article 2015 English 14373254 10.1007/s00531-014-1033-6 International Journal of Earth Sciences 104 Springer Verlag 1623 – 1638 6 Albania; Lake Ohrid; Macedonia [Southern Europe]; Mediterranean Region; climate oscillation; environmental change; geochemistry; Holocene; late glacial; paleoclimate; paleoenvironment; paleolimnology; sediment core; stable isotope https://www.scopus.com/inward/record.uri?eid=2-s2.0-84940954305&doi=10.1007%2fs00531-014-1033-6&partnerID=40&md5=41768ba3623786f013bc69a09bb6942e Cited by: 39; All Open Access, Green Open Access, Hybrid Gold Open Access Jack H. Lacey Alexander Francke Melanie J. Leng Christopher H. Vane Bernd Wagner article Morrow20158240 The San Andreas Fault Observatory at Depth (SAFOD) scientific drill hole near Parkfield, California, crosses the San Andreas Fault at a depth of 2.7 km. Downhole measurements and analysis of core retrieved from Phase 3 drilling reveal two narrow, actively deforming zones of smectite-clay gouge within a roughly 200 m wide fault damage zone of sandstones, siltstones, and mudstones. Here we report electrical resistivity and permeability measurements on core samples from all of these structural units at effective confining pressures up to 120 MPa. Electrical resistivity (~10 Ω-m) and permeability (10-21 to 10-22 m2) in the actively deforming zones were 1 to 2 orders of magnitude lower than the surrounding damage zone material, consistent with broader-scale observations from the downhole resistivity and seismic velocity logs. The higher porosity of the clay gouge, 2 to 8 times greater than that in the damage zone rocks, along with surface conduction were the principal factors contributing to the observed low resistivities. The high percentage of fine-grained clay in the deforming zones also greatly reduced permeability to values low enough to create a barrier to fluid flow across the fault. Together, resistivity and permeability data can be used to assess the hydrogeologic characteristics of the fault, key to understanding fault structure and strength. The low resistivities and strength measurements of the SAFOD core are consistent with observations of low resistivity clays that are often found in the principal slip zones of other active faults making resistivity logs a valuable tool for identifying these zones. © Published 2015. This article is a U.S. Government work and is in the public domain in the USA. 2015 English 21699313 10.1002/2015JB012214 Journal of Geophysical Research: Solid Earth 120 Blackwell Publishing Ltd 8240-8258 U.S. Geological Survey, Menlo Park, CA, United States 12 active fault; deformation; electrical resistivity; fault gouge; permeability; porosity; San Andreas Fault; sediment core; shear zone, California; Parkfield; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-84957847021&doi=10.1002%2f2015JB012214&partnerID=40&md5=6da25f74f7bc85f2db0af6ea595d49e2 cited By 8 C. Morrow D.A. Lockner S. Hickman article Coletti2015979 Until now, the lack of time-continuous, terrestrial paleoenvironmental data from the Pleistocene Arctic has made model simulations of past interglacials difficult to assess. Here, we compare climate simulations of four warm interglacials at Marine Isotope Stages (MISs) 1 (9 ka), 5e (127 ka), 11c (409 ka) and 31 (1072 ka) with new proxy climate data recovered from Lake El'gygytgyn, NE Russia. Climate reconstructions of the mean temperature of the warmest month (MTWM) indicate conditions up to 0.4, 2.1, 0.5 and 3.1 °C warmer than today during MIS 1, 5e, 11c and 31, respectively. While the climate model captures much of the observed warming during each interglacial, largely in response to boreal summer (JJA) orbital forcing, the extraordinary warmth of MIS 11c compared to the other interglacials in the Lake El'gygytgyn temperature proxy reconstructions remains difficult to explain. To deconvolve the contribution of multiple influences on interglacial warming at Lake El'gygytgyn, we isolated the influence of vegetation, sea ice and circum-Arctic land ice feedbacks on the modeled climate of the Beringian interior. Simulations accounting for climate-vegetation-land-surface feedbacks during all four interglacials show expanding boreal forest cover with increasing summer insolation intensity. A deglaciated Greenland is shown to have a minimal effect on northeast Asian temperature during the warmth of stages 11c and 31 (Melles et al., 2012). A prescribed enhancement of oceanic heat transport into the Arctic Ocean does have some effect on Lake El'gygytgyn's regional climate, but the exceptional warmth of MIS l1c remains enigmatic compared to the modest orbital and greenhouse gas forcing during that interglacial. © Author(s) 2015. 2015 English 18149324 10.5194/cp-11-979-2015 Climate of the Past 11 Copernicus GmbH 979-989 Department of Geosciences, University of Massachusetts, Amherst, MA 01003, United States; Institute of Geology and Mineralogy, University of Cologne, Zülpicher Strasse 49a, Cologne, 50674, Germany 7 boreal forest; climate forcing; climate modeling; greenhouse gas; heat transfer; lake ecosystem; land surface; marine isotope stage; paleoclimate; paleoenvironment; Pleistocene; proxy climate record, Arctic Ocean; Chukchi; Elgygytgyn Lake; Russian Federation; Russian Federation https://www.scopus.com/inward/record.uri?eid=2-s2.0-84937035355&doi=10.5194%2fcp-11-979-2015&partnerID=40&md5=d0b89744372ad865594ae5e3488be35c cited By 14 A.J. Coletti R.M. DeConto J. Brigham-Grette M. Melles article trumbull2015drilling 2015 Scientific Drilling 19 Copernicus GmbH 33--37 RB Trumbull LD Ashwal SJ Webb IV Veksler article Föller20157209 Ancient lakes represent key ecosystems for endemic freshwater species. This high endemic biodiversity has been shown to be mainly the result of intra-lacustrine diversification. Whereas the principle role of this mode of diversification is generally acknowledged, actual diversification rates in ancient lakes remain little understood. At least four types are conceivable. Diversification rates may be constant over time, they may fluctuate, rates may be higher in the initial phase of diversification, or there may be a pronounced lag phase between colonization and subsequent diversification. As understanding the tempo of diversification in ancient lake environments may help reveal the underlying processes that drive speciation and extinction, we here use the Balkan Lake Ohrid as a model system and the largest species flock in the lake, the non-pyrgulinid Hydrobiidae, as a model taxon to study changes in diversification rates over time together with the respective drivers. Based on phylogenetic, molecular-clock, lineage-through-time plot, and diversification-rate analyses we found that this potentially monophyletic group is comparatively old and that it most likely evolved with a constant diversification rate. Preliminary data of the SCOPSCO (Scientific Collaboration On Past Speciation Conditions in Lake Ohrid) deep-drilling program do indicate signatures of severe environmental/climatic perturbations in Lake Ohrid. However, so far there is no evidence for the occurrence of catastrophic environmental events. We therefore propose that the constant diversification rate observed in endemic gastropods has been caused by two factors: (i) a potential lack of catastrophic environmental events in Lake Ohrid and/or (ii) a probably high ecosystem resilience, buffering environmental changes. Parameters potentially contributing to the lake's high ecosystem resilience are its distinct bathymetry, ongoing tectonic activities, and karst hydrology. The current study not only contributes to one of the overall goals of the SCOPSCO deep-drilling program - inferring the driving forces for biotic evolution in Lake Ohrid. It might also enhance our understanding of how ecosystem resilience, in general, may promote relatively constant diversification rates in isolated ecosystems. However, we encourage future studies testing hypotheses about the lack of catastrophic events in Lake Ohrid. These studies should be based on high-resolution data for the entire geological history of the lake, and they should potentially involve information from the sediment fossil record, not only for gastropods but also for other groups with a high share of endemic taxa. © 2015 Author(s). Article 2015 English 17264170 10.5194/bg-12-7209-2015 Biogeosciences 12 Copernicus GmbH 7209 – 7222 Department of Animal Ecology and Systematics, Justus Liebig University Giessen, Heinrich-Buff-Ring 26-32, Giessen, 35392, Germany 23 Lake Ohrid; Gastropoda; Hydrobiidae; biodiversity; catastrophic event; ecosystem resilience; endemic species; evolution; gastropod; lake ecosystem; phylogeny https://www.scopus.com/inward/record.uri?eid=2-s2.0-84949651050&doi=10.5194%2fbg-12-7209-2015&partnerID=40&md5=4dc45c1bd1b383854206b08e570a06d9 Cited by: 25; All Open Access, Gold Open Access, Green Open Access K. Föller B. Stelbrink T. Hauffe C. Albrecht T. Wilke article Foerster2015333 Our understanding of the impact of climate-driven environmental change on prehistoric human populations is hampered by the scarcity of continuous paleoenvironmental records in the vicinity of archaeological sites. Here we compare a continuous paleoclimatic record of the last 20 ka before present from the Chew Bahir basin, southwest Ethiopia, with the available archaeological record of human presence in the region. The correlation of this record with orbitally-driven insolation variations suggests a complex nonlinear response of the environment to climate forcing, reflected in several long-term and short-term transitions between wet and dry conditions, resulting in abrupt changes between favorable and unfavorable living conditions for humans. Correlating the archaeological record in the surrounding region of the Chew Bahir basin, presumably including montane and lake-marginal refugia for human populations, with our climate record suggests a complex interplay between humans and their environment during the last 20 ka. The result may contribute to our understanding of how a dynamic environment may have impacted the adaptation and dispersal of early humans in eastern Africa. © 2015 Elsevier Ltd. 2015 English 02773791 10.1016/j.quascirev.2015.10.026 Quaternary Science Reviews 129 Elsevier Ltd 333-340 University of Potsdam, Institute of Earth and Environmental Science, Karl-Liebknecht-Str. 24-25, Potsdam, 14476, Germany; University of Cologne, Institute of Prehistoric Archaeology, Bernhard-Feilchenfeld-Str. 11, Cologne, 50969, Germany; Eberhard Karls Universität Tuebingen, Department of Earth Sciences, Senckenberg Center for Human Evolution and Palaeoenvironment (HEP-Tuebingen), Hölderlinstrasse 12, Tübingen, 72074, Germany; Addis Ababa University, School of Earth Sciences, P. O. Box 1176, Addis Ababa, Ethiopia; Aberystwyth University, Department of Geography and Earth Sciences, Aberystwyth, SY23 3DB, United Kingdom; University of Cologne, Seminar for Geography and Education, Gronewaldstrasse 2, Cologne, 50931, Germany Geology; Natural sciences, Adaption; Archeology; Chew Bahir; Foragers; Humid periods; Hunter-gatherers; Migration; Paleoclimates; Pastoralism; Push factor, Climate change, adaptation; archaeological evidence; climate forcing; climate variation; environmental change; historical time (human history); migration; paleoclimate; paleoenvironment; pastoralism, Africa; Ethiopia; Kenya https://www.scopus.com/inward/record.uri?eid=2-s2.0-84946401492&doi=10.1016%2fj.quascirev.2015.10.026&partnerID=40&md5=12b70211dfc84dee08f9ae083faca1af cited By 42 V. Foerster R. Vogelsang A. Junginger A. Asrat H.F. Lamb F. Schaebitz M.H. Trauth article Wang2015895 The Sifangtai and Mingshui formations were continuously cored in the SK-1n borehole (China Cretaceous Continental Scientific Drilling-SongKe1-the north borehole). The core is 767.96 m long, and the recovery is 94.7%. The ages of the formations range from middle Campanian to Danian. The sequence and process of lithology-lithofacies and cyclic stratigraphy were described in detail. Eight litho-types compose the Sifangtai Formation, and 15 litho-types compose the Mingshui Formation. Deposition was predominantly in meandering river and lacustrine environments, including 10 microfacies in the Sifangtai Formation and 15 microfacies in the Mingshui Formation. The complete sequence is composed of 535 m-scale cycles (sixth-order cycle), 152 fifth-order cycles, 42 fourth-order cycles and five third-order cycles. The centimeter-scale description of the section revealed some previously unknown horizons such as a special type of mudstone, marl, volcanic ash and favorable sand reservoirs in the formations. The new-found evidence is very important for the interpretation of the evolution of the basin, conditions such as lake oxic events, the K/Pg boundary, tectonism in the late sag basin stage, and the reservoir-cap rock assemblages in the shallow stratigraphy. © 2015 China University of Geosciences (Beijing) and Peking University. 2015 English 16749871 10.1016/j.gsf.2015.02.003 Geoscience Frontiers 6 Elsevier B.V. 895-912 Research Institute of Petroleum Exploration and Development-Northwest (NWGI), PetroChina, Lanzhou, 730020, China; College of Earth Sciences, Jilin University, Changchun, 130061, China; Research Center of Palaeontology and Stratigraphy, Jilin University, Changchun, 130026, China; School of Earth Sciences and Resources, China University of GeosciencesBeijing 100083, China; Institute of Exploration and Development, Daqing Oilfield Company Ltd., Daqing, Heilongjiang 163712, China 6 age determination; basin evolution; borehole; Campanian; Danian; drilling; facies analysis; geological record; lithofacies; lithology; sedimentary structure; stratigraphy; tectonic setting, China; Songliao Basin https://www.scopus.com/inward/record.uri?eid=2-s2.0-84946474115&doi=10.1016%2fj.gsf.2015.02.003&partnerID=40&md5=ad6a5871bbe1c8983b5c29bb685cf5ac cited By 14 G. Wang R. Cheng P. Wang Y. Gao C. Wang Y. Ren Q. Huang article Oehlerich2015189 First results of strontium, calcium, carbon and oxygen isotope analyses of bulk carbonates from a 106m long sediment record of Laguna Potrok Aike, located in southern Patagonia are presented. Morphological and isotopic investigations of μm-sized carbonate crystals in the sediment reveal an endogenic origin for the entire Holocene. During this time period the calcium carbonate record of Laguna Potrok Aike turned out to be most likely ikaite-derived. As ikaite precipitation in nature has only been observed in a narrow temperature window between 0 and 7°C, the respective carbonate oxygen isotope ratios serve as a proxy of hydrological variations rather than of palaeotemperatures. We suggest that oxygen isotope ratios are sensitive to changes of the lake water balance induced by intensity variations of the Southern Hemisphere Westerlies and discuss the role of this wind belt as a driver for climate change in southern South America. In combination with other proxy records the evolution of westerly wind intensities is reconstructed. Our data suggest that weak SHW prevailed during the Lateglacial and the early Holocene, interrupted by an interval with strengthened Westerlies between 13.4 and 11.3kacalBP. Wind strength increased at 9.2kacalBP and significantly intensified until 7.0kacalBP. Subsequently, the wind intensity diminished and stabilised to conditions similar to present day after a period of reduced evaporation during the "Little Ice Age". Strontium isotopes (87Sr/86Sr ratio) were identified as a potential lake-level indicator and point to a lowering from overflow conditions during the Glacial (~17kacalBP) to lowest lake levels around 8kacalBP. Thereafter the strontium isotope curve resembles the lake-level curve which is stepwise rising until the "Little Ice Age". The variability of the Ca isotope composition of the sediment reflects changes in the Ca budget of the lake, indicating higher degrees of Ca utilisation during the period with lowest lake level. © 2015 Elsevier Ltd. Article 2015 10.1016/j.quascirev.2015.02.006 Quaternary Science Reviews 114 189 – 202 Argentina; Laguna Potrok Aike; Patagonia; Santa Cruz [Argentina]; Budget control; Calcite; Calcium; Calcium carbonate; Carbon; Carbonation; Climate change; Glacial geology; Isotopes; Lakes; Oxygen; Sediments; Calcium isotopes; Carbon isotopes; ICDP; Ikaite; Lake sediments; Oxygen isotopes; PASADO; Southern south america; Strontium isotopes; carbonate; climate variation; evaporation; Holocene; ikaite; isotopic composition; lacustrine deposit; late glacial; oxygen isotope; paleoclimate; paleotemperature; proxy climate record; strontium isotope; westerly; Strontium https://www.scopus.com/inward/record.uri?eid=2-s2.0-84924232224&doi=10.1016%2fj.quascirev.2015.02.006&partnerID=40&md5=0dead064d49658e62990ecf4dccbcb2a Cited by: 16 M. Oehlerich C. Mayr N. Gussone A. Hahn S. Hölzl A. Lücke C. Ohlendorf S. Rummel B.M.A. Teichert B. Zolitschka article Trauth201521 Article 2015 10.1016/j.jhevol.2015.03.011 Journal of Human Evolution 87 21 – 31 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84944174753&doi=10.1016%2fj.jhevol.2015.03.011&partnerID=40&md5=ae529983af830e2e904d7f18894db6c0 Cited by: 29 Martin H. Trauth Andreas G.N. Bergner Verena Foerster Annett Junginger Mark A. Maslin Frank Schaebitz article Zimmermann201520 Article 2015 10.1016/j.palaeo.2015.03.006 Palaeogeography, Palaeoclimatology, Palaeoecology 427 20 – 31 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84961362678&doi=10.1016%2fj.palaeo.2015.03.006&partnerID=40&md5=f1601a2513e23c9a06285de679190485 Cited by: 4; All Open Access, Green Open Access Claudia Zimmermann Guillaume Jouve Reinhard Pienitz Pierre Francus Nora I. Maidana article Jin201563 Geochemistry of basin sediments from semi-arid regions is valuable to understand past hydroclimatic changes. Here, we investigate the links of sedimentary geochemistry (Rb, Sr, Ca/Zr, TOC, and %CaCO3), carbonate mineralogy and ostracod shell δ18O of Lake Qinghai, a basin proximal to major dust production centers at mid-latitudes of the Northern Hemisphere, to changes in depositional conditions and hydroclimate during the past 32ka. Surface lacustrine sediments are characterized by low-Rb, high-Sr, low-Rb/Sr, high-%CaCO3 and high-Ca/Zr values, in contrast to the chemical compositions of eolian loess (high-Rb, low-Sr, high-Rb/Sr, low-%CaCO3, and low-Ca/Zr). A direct comparison of soluble Ca and Sr in two short cores with instrumental water discharge data suggests that lacustrine precipitates in Lake Qinghai are dominated by authigenic aragonite formed under Ca2+-limited water conditions, and that the accumulation rate of aragonite dominantly depends on solute fluxes into the lake during the rainy seasons (late May to September). Our high-resolution down-core records show that sediments during the last glacial (~32-19.8ka) had high-Rb, low-Sr, low-%CaCO3, and low-Ca/Zr, indicating eolian dust (loess) accumulation in a desiccated basin under dry glacial conditions, further supported by grain size and pollen results. This type of sedimentation was maintained during the last deglacial (~19.8-11.5ka), but interrupted by episodic lacustrine precipitates with high-Sr, high-%CaCO3, high-Ca/Zr, and low-Rb. At ~11.5ka, sedimentary Rb/Sr, Ca/Zr, %CaCO3 and TOC show dramatic and permanent changes, implying an abrupt shift in the atmospheric circulation at the onset of the Holocene in the Lake Qinghai region. Lacustrine precipitates have persisted throughout the Holocene with a maximum during the early to mid-Holocene (~10.5-8.0ka). Since ~8.0ka, the gradual and significant decreases in aragonite and Sr accumulations in tandem with increasing dust deposit and more positive ostracod δ18O may be linked to a weakening of Asian summer monsoons during the mid-to-late Holocene. Overall, our records appear to show a high sensitivity of sediment development and geochemistry in Lake Qinghai to the regional hydroclimate changes since the last glacial. © 2015 Elsevier Ltd. 2015 English 02773791 10.1016/j.quascirev.2015.05.015 Quaternary Science Reviews 122 Elsevier Ltd 63-73 State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, 710075, China; Institute of Global Environmental Change, Xi'an Jiaotong University, Xi'an, 710049, China; Research School of Earth Sciences, The Australian National University, Canberra, ACT 0200, Australia; College Resources and Environmental Science, Nanjing Agricultural University, Nanjing, 210095, China Animals; Arid regions; Calcium; Carbonate minerals; Dust; Geochemistry; Glacial geology; Lakes; Minerals; Precipitates; Rubidium; Sedimentology, Asian dust; Hydroclimate; Lake Qinghai; Lake waters; Sediment geochemistries, Sediments, aragonite; calcium carbonate; chemical composition; climate variation; eolian process; lacustrine deposit; Last Glacial; Northern Hemisphere; ostracod; paleoclimate; sediment chemistry; semiarid region; shell, China; Qinghai; Qinghai Lake, Ostracoda https://www.scopus.com/inward/record.uri?eid=2-s2.0-84930932715&doi=10.1016%2fj.quascirev.2015.05.015&partnerID=40&md5=f8021dc85717cd55118558fb67b0115e cited By 74 Z. Jin Z. An J. Yu F. Li F. Zhang article Xu201510 A high temperature water base drilling fluid was formulated with sodium bentonite and attapulgite, and a high temperature water-in-oil stabilizer, MG-H2 which is synthesized through emulsion polymerization. Laboratory evaluation of the drilling fluid showed that, after aging at 240 °C, the drilling fluid still retained satisfactory rheology and filtration properties. It had good inhibitive capacity and was resistant to contamination caused by the introduction of 10% clay, or a combination of 5% NaCl and 1% CaCl2. It also had good lubricity at high temperature. The formulation of this high temperature drilling fluid lays the foundation for the formulation of an ultra-high temperature drilling fluid, say, 260 °C, for the drilling of the Well Songke-2. Article 2015 Chinese 10015620 10.3969/j.issn.1001-5620.2015.01.003 Drilling Fluid and Completion Fluid 32 North China Petroleum Administration Drilling Technology Research Institute 10–13 and 97 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84932100495&doi=10.3969%2fj.issn.1001-5620.2015.01.003&partnerID=40&md5=19acc47a170bd5eb3b1b0b18df4ba469 Cited by: 11 Jie Xu Xiaoming Wu Yongyi Zhu V.F. Chikhotkin Mingbiao Xu Chuan Wu Wenlong Zheng article Bennington20151033 We present jointly inverted models of P-wave velocity (Vp) and electrical resistivity for a two-dimensional profile centered on the San Andreas Fault Observatory at Depth (SAFOD). Significant structural similarity between main features of the separately inverted Vp and resistivity models is exploited by carrying out a joint inversion of the two datasets using the normalized cross-gradient constraint. This constraint favors structurally similar Vp and resistivity images that adequately fit the seismic and magnetotelluric (MT) datasets. The new inversion code, tomoDDMT, merges the seismic inversion code tomoDD and the forward modeling and sensitivity kernel subroutines of the MT inversion code OCCAM2DMT. TomoDDMT is tested on a synthetic dataset and demonstrates the code’s ability to more accurately resolve features of the input synthetic structure relative to the separately inverted resistivity and velocity models. Using tomoDDMT, we are able to resolve a number of key issues raised during drilling at SAFOD. We are able to infer the distribution of several geologic units including the Salinian granitoids, the Great Valley sequence, and the Franciscan Formation. The distribution and transport of fluids at both shallow and great depths is also examined. Low values of velocity/resistivity attributed to a feature known as the Eastern Conductor (EC) can be explained in two ways: the EC is a brine-filled, high porosity region, or this region is composed largely of clay-rich shales of the Franciscan. The Eastern Wall, which lies immediately adjacent to the EC, is unlikely to be a fluid pathway into the San Andreas Fault’s seismogenic zone due to its observed higher resistivity and velocity values. © 2014, Springer Basel. 2015 English 00334553 10.1007/s00024-014-1002-9 Pure and Applied Geophysics 172 Birkhauser Verlag AG 1033-1052 University of Wisconsin-Madison, Madison, WI, United States; Laboratory of Seismology and Physics of the Earth’s Interior, School of Earth and Space Sciences, University of Science and Technology of China, Hefei, China; U.S. Geological Survey, Denver, CO, United States 5 Codes (symbols); Magnetotellurics; Seismic waves; Seismographs; Strike-slip faults; Tectonics; Transport properties; Velocity; Wave propagation, Inverse theory; Joint inversion; Magnetotelluric data; Resistivity images; Seismic tomography; Sensitivity kernels; Structural similarity; Two-dimensional profiles, Seismology, data inversion; data set; electrical resistivity; gradient analysis; inverse analysis; magnetotelluric method; San Andreas Fault; seismic data; seismic tomography; seismic zone; velocity structure https://www.scopus.com/inward/record.uri?eid=2-s2.0-84926167005&doi=10.1007%2fs00024-014-1002-9&partnerID=40&md5=e9559bc10b1a3120e538fd44cdf425fd cited By 41 N.L. Bennington H. Zhang P.A. Bedrosian article Gupta20151511 Artificial water reservoir-triggered earthquakes have continued at Koyna in the Deccan Traps province, India, since the impoundment of the Shivaji Sagar reservoir in 1962. Existing models, to comprehend the genesis of triggered earthquakes, suffer from lack of observations in the near field. To investigate further, scientific deep drilling and setting up a fault zone observatory at depth of 5–7 km is planned in the Koyna area. Prior to undertaking deep drilling, an exploratory phase of investigations has been launched to constrain subsurface geology, structure and heat flow regime in the area that provide critical inputs for the design of the deep borehole observatory. Two core boreholes drilled to depths of 1,522 and 1,196 m have penetrated the Deccan Traps and sampled the granitic basement in the region for the first time. Studies on cores provide new and direct information regarding the thickness of the Deccan Traps, the absence of infra-Trappean sediments and the nature of the underlying basement rocks. Temperatures estimated at a depth of 6 km in the area, made on the basis of heat flow and thermal properties data sets, do not exceed 150 °C. Low-elevation airborne gravity gradient and magnetic data sets covering 5,012 line km, together with high-quality magnetotelluric data at 100 stations, provide both regional information about the thickness of the Deccan Traps and the occurrence of localized density heterogeneities and anomalous conductive zones in the vicinity of the hypocentral zone. Acquisition of airborne LiDAR data to obtain a high-resolution topographic model of the region has been completed over an area of 1,064 km2 centred on the Koyna seismic zone. Seismometers have been deployed in the granitic basement inside two boreholes and are planned in another set of six boreholes to obtain accurate hypocentral locations and constrain the disposition of fault zones. © 2014, Springer-Verlag Berlin Heidelberg. 2015 English 14373254 10.1007/s00531-014-1128-0 International Journal of Earth Sciences 104 Springer Verlag 1511-1522 National Disaster Management Authority, New Delhi, India; CSIR-National Geophysical Research Institute, Hyderabad, India; Ministry of Earth Sciences, New Delhi, India 6 borehole; deep drilling; earthquake; earthquake hypocenter; fault zone; heat flow; lidar; reservoir; seismic zone; seismicity; trigger mechanism, Deccan; India; Koyna; Maharashtra, Calluna vulgaris https://www.scopus.com/inward/record.uri?eid=2-s2.0-84940961358&doi=10.1007%2fs00531-014-1128-0&partnerID=40&md5=dcc1ce1290012760f6d9cec1270f0616 cited By 69 H. Gupta N. Purnachandra Rao S. Roy K. Arora V.M. Tiwari P.K. Patro H.V.S. Satyanarayana D. Shashidhar K. Mallika V.V. Akkiraju D. Goswami D. Vyas G. Ravi K.N.S.S.S. Srinivas M. Srihari S. Mishra C.P. Dubey D.C.V. Raju U. Borah K. Chinna Reddy N. Babu S. Rohilla U. Dhar M. Sen Y.J. Bhaskar Rao B.K. Bansal S. Nayak article Abercrombie20154263 I use a well-recorded earthquake sequence to investigate the uncertainties of earthquake stress drops calculated using an empirical Green’s function (EGF) approach. The earthquakes in the largest (M~ 2.1) repeating sequence targeted by the San Andreas Observatory at Depth (SAFOD), Parkfield, California, are recorded by multiple borehole stations and have simple sources, well-constrained stress drops, and abundant smaller earthquakes to use as EGFs. I perform three tests to estimate quantitatively the likely uncertainties to arise in less optimal settings. I use EGF earthquakes with a range of cross-correlation values and separation distances fromthe main earthquakes. The stress dropmeasurements decrease by a factor of 3 as the quality of the EGF assumption decreases; a good EGF must be located within approximately one source dimension of the large earthquake, with high cross correlation. I subsample the large number ofmeasurements for the main earthquakes to investigate the expected stress drop uncertainties in studies where fewer stations or EGFs are available. If only one measurement is available, the uncertainties are likely to be at least 50%. The uncertainties decrease to <20% with five ormore measurements; usingmultiple EGFs is a good alternative to multiple stations. To investigate the effects of limited frequency bandwidth, I recalculate the corner frequencies after progressively decimating the sample rate. Decreasing the high-frequency limit of the bandwidth decreases the estimate of the corner frequency (and stress drop). The corner frequency may be underestimated if it is within a factor of 3 of the maximum frequency of the signal. © 2015. American Geophysical Union. All Rights Reserved. 2015 English 21699313 10.1002/2015JB011984 Journal of Geophysical Research: Solid Earth 120 Blackwell Publishing Ltd 4263-4277 Department of Earth and Environment, Boston University, Boston, MA, United States 6 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84930532967&doi=10.1002%2f2015JB011984&partnerID=40&md5=7c13a8fd013160f67bff1cd32f6dc64b cited By 109 R.E. Abercrombie article Flechsig20152087 The Mýtina maar is the first known Quaternary maar in the Bohemian Massif. Based on the results of Mrlina et al. (J Volcanol Geother Res 182:97–112, 2009), a multiparametric geophysical (electrical resistivity tomography, gravimetry, magnetometry, seismics) and geological/petrochemical research study had been carried out. The interpretation of the data has provided new information about the inner structure of the volcanic complex: (1) specification of the depth of post-volcanic sedimentary fill (up to ~100 m) and (2) magnetic and resistivity signs of one (or two) hidden volcanic structures interpreted as intrusions or remains of a scoria cone. The findings at the outer structure of the maar incorporate the (1) evidence of circular fracture zones outside the maar, (2) detection and distribution of volcanic ejecta and tephra-fall deposits at the surface, and (3) indications from electrical resistivity tomography and gravity data in the area between the Mýtina maar and Železná hůrka scoria cone, interpreted as a palaeovalley, filled by volcaniclastic rocks, and aligned along the strike line (NW–SE) of the Tachov fault zone. These findings are valuable contributions to extend the knowledge about structure of maar volcanoes in general. Because of ongoing active magmatic processes in the north-east part of the Cheb Basin (ca. 15–30 km north of the investigation area), the Mýtina maar-diatreme volcano and surroundings is a suitable key area for research directed to reconstruction of the palaeovolcanic evolution and assessment of possible future hazard potential in the Bohemian Massif. © 2015, Springer-Verlag Berlin Heidelberg. Article 2015 English 14373254 10.1007/s00531-014-1136-0 International Journal of Earth Sciences 104 Springer Verlag 2087 – 2105 8 Bohemian Massif; Cheb Basin; Czech Republic; Karlovarsky; geological survey; geophysical survey; maar; Quaternary; reconstruction; volcanism https://www.scopus.com/inward/record.uri?eid=2-s2.0-84945491128&doi=10.1007%2fs00531-014-1136-0&partnerID=40&md5=c60ec72595e852f74ae274b3647d07f8 Cited by: 17 Christina Flechsig Jens Heinicke Jan Mrlina Horst Kämpf Tobias Nickschick Alina Schmidt Tomáš Bayer Thomas Günther Carsten Rücker Elisabeth Seidel Michal Seidl article Chan20151549 The availability of a deep borehole in northeastern Alberta provides an unprecedented opportunity to study the in situ metamorphic craton rocks. This borehole reaches a depth of 2.4 km, with 1.8 km in the crystalline rocks, and is the only known borehole allowing access into the deeper rocks of the metamorphic Canadian Shield. In 2011, a zero-offset vertical seismic profile (VSP) was acquired to assist in the interpretation of seismic reflection data and geophysical logs. Three sets of upgoing tube waves interpreted from the raw profile correspond to the small-scale fluctuations in the borehole diameters and fracture zone in the crystalline rocks. A comparison between sonic log velocities and VSP velocities reveals a zone with increased velocity that could be due to the change in rock composition and texture in the basement rocks. The final processed profile is used to generate corridor stacks for differentiating between primary reflections and multiples in the seismic reflection profile. Analysis of the zero-offset VSP verifies existing log interpretation on the presence of fractures and the possible lithological changes in the metamorphic rocks of the Canadian Shield. © 2014, The Author(s). Article 2015 English 14373254 10.1007/s00531-014-1110-x International Journal of Earth Sciences 104 Springer Verlag 1549 – 1562 6 Alberta; Canada; Canadian Shield; borehole; craton; metamorphic rock; seismic reflection; seismic velocity; vertical seismic profile https://www.scopus.com/inward/record.uri?eid=2-s2.0-84940959788&doi=10.1007%2fs00531-014-1110-x&partnerID=40&md5=1f312df547f362767159541c1a79e9ec Cited by: 7; All Open Access, Hybrid Gold Open Access Judith Chan Douglas R. Schmitt article Chan20151549 The availability of a deep borehole in northeastern Alberta provides an unprecedented opportunity to study the in situ metamorphic craton rocks. This borehole reaches a depth of 2.4 km, with 1.8 km in the crystalline rocks, and is the only known borehole allowing access into the deeper rocks of the metamorphic Canadian Shield. In 2011, a zero-offset vertical seismic profile (VSP) was acquired to assist in the interpretation of seismic reflection data and geophysical logs. Three sets of upgoing tube waves interpreted from the raw profile correspond to the small-scale fluctuations in the borehole diameters and fracture zone in the crystalline rocks. A comparison between sonic log velocities and VSP velocities reveals a zone with increased velocity that could be due to the change in rock composition and texture in the basement rocks. The final processed profile is used to generate corridor stacks for differentiating between primary reflections and multiples in the seismic reflection profile. Analysis of the zero-offset VSP verifies existing log interpretation on the presence of fractures and the possible lithological changes in the metamorphic rocks of the Canadian Shield. © 2014, The Author(s). Article 2015 English 14373254 10.1007/s00531-014-1110-x International Journal of Earth Sciences 104 Springer Verlag 1549 – 1562 6 Alberta; Canada; Canadian Shield; borehole; craton; metamorphic rock; seismic reflection; seismic velocity; vertical seismic profile https://www.scopus.com/inward/record.uri?eid=2-s2.0-84940959788&doi=10.1007%2fs00531-014-1110-x&partnerID=40&md5=1f312df547f362767159541c1a79e9ec Cited by: 7; All Open Access, Hybrid Gold Open Access Judith Chan Douglas R. Schmitt article Thomas2015546 A long sedimentary core has been recently retrieved from the Dead Sea Basin (DSB) within the framework of the ICDP-sponsored Dead Sea Deep Drilling Project. Contrasting climatic intervals were evident by distinctive lithological facies such as laminated aragonitic muds and evaporites. A geomicrobiological investigation was conducted in representative sediments of this core. To identify the microbial assemblages present in the sediments and their evolution with changing depositional environments through time, the diversity of the 16S rRNA gene was analyzed in gypsum, aragonitic laminae, and halite samples. The subsurface microbial community was largely dominated by the Euryarchaeota phylum (Archaea). Within the latter, Halobacteriaceae members were ubiquitous, probably favored by their 'high salt-in' osmotic adaptation which also makes them one of the rare inhabitants of the modern Dead Sea. Bacterial community members were scarce, emphasizing that the 'low salt-in' strategy is less suitable in this environment. Substantial differences in assemblages are observed between aragonitic sediments and gypsum-halite ones, independently of the depth and salinity. The aragonite sample, deposited during humid periods when the lake was stratified, consists mostly of the archaeal MSBL1 and bacterial KB1 Candidate Divisions. This consortium probably relies on compatible solutes supplied from the lake by halotolerant species present in these more favorable periods. In contrast, members of the Halobacteriaceae were the sole habitants of the gypsum-halite sediments which result from a holomictic lake. Although the biomass is low, these variations in the observed subsurface microbial populations appear to be controlled by biological conditions in the water column at the time of sedimentation, and subsequently by the presence or absence of stratification and dilution in the lake. As the latter are controlled by climatic changes, our data suggest a relationship between local lacustrine subsurface microbial assemblages and large-scale climatic variations over the Dead Sea Basin. © 2015 John Wiley & Sons Ltd. 2015 English 14724677 10.1111/gbi.12151 Geobiology 13 Blackwell Publishing Ltd 546-561 Department of Earth Sciences, University of Geneva, Geneva, Switzerland; Leibniz Institute for Freshwater Ecology and Inland Fisheries, Stechlin, Germany 6 climate variation; halite; lacustrine deposit; lithology; microbial community; paleoclimate; salinity; sediment core; sedimentation rate, Dead Sea, Archaea; Bacteria (microorganisms); Euryarchaeota; Halobacteriaceae, archaeal DNA; RNA 16S; salt water, archaeon; classification; climate; DNA sequence; Euryarchaeota; genetics; isolation and purification; Israel; Jordan; microbiology; molecular genetics; phylogeny; sediment, Archaea; Climate; DNA, Archaeal; Euryarchaeota; Geologic Sediments; Israel; Jordan; Molecular Sequence Data; Phylogeny; RNA, Ribosomal, 16S; Saline Waters; Sequence Analysis, DNA https://www.scopus.com/inward/record.uri?eid=2-s2.0-84944145632&doi=10.1111%2fgbi.12151&partnerID=40&md5=10c4d45160776d89c4c0e7f2acd7bdd3 cited By 14 C. Thomas D. Ionescu D. Ariztegui The team article Costa2015467 The Indo-Pacific Warm Pool (IPWP) is an important driver of global climate, but its response to and involvement in paleoclimate change is poorly constrained. We generated a new record of sediment geochemistry from Lake Towuti (2.5°S, 121.5°E), Indonesia, located in the heart of the IPWP, to investigate changes in hydrological connectivity with upstream lakes and the extent of lake mixing and oxygenation during paleoclimate changes over the last 60,000. years BP (60. ka). Lake Towuti is located at the downstream end of the Malili Lakes, a chain of large, ancient, and biologically diverse tectonic lakes occupying a geologically heterogeneous terrain in central Sulawesi, Indonesia. Major and trace element data from river and lake sediments suggest no changes in sediment provenance during the Last Glacial Maximum (LGM), indicating that some of the Malili Lakes remained hydrologically open despite a regionally drier climate. However, samples from the LGM are uniformly less enriched in trace elements than samples from the Holocene and Marine Isotope Stage 3 (MIS3), which suggests a decrease in weathering intensity during the LGM, likely in response to decreased precipitation and temperature. Changes in Fe and other redox-sensitive trace element concentrations indicate changes in water column oxygenation, with the highest oxygen availability occurring during the LGM (15-35. ka) likely due to more frequent and/or deeper mixing of Lake Towuti's water column. The glacial-interglacial trend in lake oxygenation corresponds with changes in regional precipitation and associated changes in the seasonal cycle. The high degree of faunal endemism in these lakes may be related to changes in the lake geochemistry associated with glacial-interglacial environmental variability driven by changing inputs and redox variability. © 2014 Elsevier B.V. Article 2015 English 00310182 10.1016/j.palaeo.2014.10.009 Palaeogeography, Palaeoclimatology, Palaeoecology 417 Elsevier 467 – 475 Greater Sunda Islands; Lake Towuti; Malili Lakes; South Sulawesi; Sulawesi; Sunda Isles; climate variation; connectivity; glacial-interglacial cycle; mixing; oxygenation; paleoclimate; paleolimnology; provenance; seasonal variation; trace element https://www.scopus.com/inward/record.uri?eid=2-s2.0-84918508289&doi=10.1016%2fj.palaeo.2014.10.009&partnerID=40&md5=c2a9befb55919ad23eb144f81dd8fc13 Cited by: 38 K.M. Costa J.M. Russell H. Vogel S. Bijaksana article Pollitz20152835 A series of near-surface chemical explosions conducted at the San Andreas Fault Observatory at Depth (SAFOD) were recorded by high-frequency downhole receiver arrays in separate experiments in November 2003 and May 2005. The 2003 experiment involved ~100 kg shots detonated along a 46-km-long line (Hole–Ryberg line) centered on SAFOD and recorded by 32 three-component geophones in the pilot hole between 0.8 and 2.0 km depth. The 2005 experiment involved ~36 kg shots detonated at Parkfield Area Seismic Observatory (PASO) stations (at ~1–8 km offset) recorded by 80 three-component geophones in the main hole between the surface and 2.4 km depth. These data sample the downgoing seismic wavefield and constrain the shallow velocity and attenuation structure, as well as the first-order characteristics of the source. Using forward modeling on a velocity structure designed for the near field, both observed P- and S-wave energy for the PASO shots are identified with the travel times expected for direct and/or reflected phases. Larger-offset recordings from shots along the Hole–Ryberg line reveal substantial SVand SH energy, especially southwest of SAFOD from the source as indicated by P-to-S amplitude ratios. The generated SV energy is interpreted to arise chiefly from P-to-S conversions at subhorizontal discontinuities. This provides a simple mechanism for often-observed low P-to-S amplitude ratios from nuclear explosions in the far field, as originating from strong near-field wave conversions. © 2015, Seismological Society of America. All rights reserved. 2015 English 00371106 10.1785/0120140242 Bulletin of the Seismological Society of America 105 Seismological Society of America 2835-2851 U.S. Geological Survey, 345 Middlefield Road, MS 977, Menlo Park, CA 94025, United States 6 Explosions; Nuclear explosions; Observatories; Seismology; Strike-slip faults; Wave energy conversion, Amplitude ratios; Downhole receivers; Forward modeling; High frequency HF; Reflected phasis; San Andreas fault; Seismic wavefields; Velocity structure, Shear waves, explosion; geophone; S-wave; seismic discrimination; seismic velocity; wave generation, California; Parkfield; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-84949257201&doi=10.1785%2f0120140242&partnerID=40&md5=b965f7b62d7a2190e3172753b5cfdfe9 cited By 0 F.F. Pollitz W. Ellsworth J. Rubinstein book Werner2015327 Impact craters on terrestrial planets are key to studying planetary geology and geophysics as well as the planetary evolution remaining as geologic features at a planet's surface. To best use the cratering record history and interpret the planetary evolution, one needs to combine a wide set of processes and parameters. This chapter reviews impact cratering processes, estimates of average impact velocities, and impact probabilities for terrestrial planets. The basics of the impact crater scaling are outlined at an up-to-date level, describing the correlation of a measured impact crater diameter and the mass and size of a body that created the impact structure. Scaling laws for large impact craters are compared with the results of the direct numerical modeling of impact cratering.The accumulation rate for impact craters on terrestrial planets is univocally considered to be constant (within a factor of 2) during the youngest 3. Ga of the solar system history, while crater-forming projectile flux evolution for the very earliest phase is debated and relates to the preferred solar system evolution concept. The intermediate flux is constrained by observations from the Earth's Moon. Different cratering chronology models are described. Measuring the number of accumulated craters at predefined sizes in a geologically outlined area of interest, one can estimate the relative and model absolute ages of the visible surface, assuming older surfaces accumulate larger number of craters. Possible challenges for this technique and the interpretation of measured size-frequency distributions of impact craters are discussed, including secondary cratering, atmospheric breakup, geologic activity, and target properties, which all modify the cratering record. © 2015 Elsevier B.V. All rights reserved. 2015 10.1016/B978-0-444-53802-4.00170-6 Treatise on Geophysics: Second Edition 10 327-365 University of Oslo, Oslo, Norway; Institute for Dynamics of Geospheres, Moscow, Russian Federation https://www.scopus.com/inward/record.uri?eid=2-s2.0-84984927548&doi=10.1016%2fB978-0-444-53802-4.00170-6&partnerID=40&md5=346c5913dfcf2112e9f5774c5f21670f cited By 26 S.C. Werner B.A. Ivanov article Blichert-Toft20152396 To constrain the origin of komatiites from the Barberton Greenstone Belt, South Africa, we measured 147Sm-143Nd and 176Lu-176Hf compositions for 18 komatiites from core obtained during the International Continental Drilling Program in the Komati Formation of the Barberton Belt, as well as 33 komatiites from surface outcrops of the Komati, Hooggenoeg, and Weltevreden Formations, these latter for purposes of comparison between core and surface samples. Magmatic clinopyroxene from surface samples near the drill site was also analyzed. For the Lu-Hf isotope system, the Komati Formation core and surface samples including the clinopyroxene define a linear array whose slope corresponds to an age of 3426 ± 16 Ma (MSWD = 118; εHf(T) = +2.2), which is slightly younger than the accepted age of the rocks (3.48 Ga). The Sm-Nd isotope data for the same set of samples likewise fall along a linear array also yielding a younger age of 3339 ± 12 Ma (MSWD = 42; εNd(T) = +2.8). The high MSWD for both isotope systems indicate substantial scatter at variance with normal magmatic processes, likely implying element mobility disturbing even these relatively robust isotopic systems shortly after eruption of the lavas. The average initial εNd and εHf of the core samples at 3.48 Ga are +0.45 and +1.4, respectively, in overall accordance with the positive errorchron intercepts and a depleted mantle source at 3.5 Ga. In contrast, the clinopyroxene and their host rocks have strongly positive εHf(T) of about +5 and negative εNd(T) of about -2. Given the overall scatter of the whole-rock data, the most robust constraint on the composition of the komatiite source comes from the clinopyroxene. Their positive εHf(T) is in line with, though somewhat higher than other results from komatiites from the Komati Formation, but their negative εNd(T) is unexpected in that it indicates a source with long-term low Sm/Nd, which is at odds with its long-term high Lu/Hf. This signature is also found in the trace element compositions of some of the komatiites, such as moderately enriched LREE, negative Hf anomalies, and low Hf/Sm ratios. The origin of these features is uncertain but one possibility is that the discordance between the Hf and Nd isotope systems reflects the presence of deepsea sediments in the source of some of the Barberton komatiites. The possible presence of a surface component in an ancient deep mantle source has wide-ranging implications for mantle-crust interaction and dynamics in the early Earth and for constraining a minimum age for the onset of plate tectonics. © Walter de Gruyter Berlin/Boston 2015. Article 2015 English 0003004X 10.2138/am-2015-5325 American Mineralogist 100 Walter de Gruyter GmbH 2396 – 2411 11-12 Barberton Greenstone Belt; Binary alloys; Core samples; Gallium alloys; Hafnium; Infill drilling; Isotopes; Lutetium alloys; Neodymium; Samarium alloys; Trace elements; chert; Clinopyroxenes; Deep sea sediment; Greenstone belts; Hf isotope; International Continental Drilling Program; Invited Centennial article; Komatiites; Sm-Nd isotope; Archean; chert; clinopyroxene; deep-sea sediment; drilling; hafnium; isotopic composition; komatiite; neodymium; research program; Neodymium alloys https://www.scopus.com/inward/record.uri?eid=2-s2.0-84948776885&doi=10.2138%2fam-2015-5325&partnerID=40&md5=3310f90d2aacb0c1baf6bab6712e631a Cited by: 41 Janne Blichert-Toft Nicholas T. Arndt Allan Wilson Grace Coetzee phdthesis hedin_geophysical_2015 The Collisional Orogeny in the Scandinavian Caledonides (COSC) project aims to provide a deeper understanding of mountain belt dynamics through scientific deep drilling in the central parts of the ... Ph.{D}. thesis 2015 eng Uppsala University

Uppsala, Sweden

http://uu.diva-portal.org/smash/record.jsf?pid=diva2:849748 Peter Hedin article Raschke20151071 The complex impact structure El'gygytgyn (age 3.6 Ma, diameter 18 km) in northeastern Russia was formed in ~88 Ma old volcanic target rocks of the Ochotsk-Chukotsky Volcanic Belt (OCVB). In 2009, El'gygytgyn was the target of a drilling project of the International Continental Scientific Drilling Program (ICDP), and in summer 2011 it was investigated further by a Russian-German expedition. Drill core material and surface samples, including volcanic target rocks and impactites, have been investigated by various geochemical techniques in order to improve the record of trace element characteristics for these lithologies and to attempt to detect and constrain a possible meteoritic component. The bedrock units of the ICDP drill core reflect the felsic volcanics that are predominant in the crater vicinity. The overlying suevites comprise a mixture of all currently known target lithologies, dominated by felsic rocks but lacking a discernable meteoritic component based on platinum group element abundances. The reworked suevite, directly overlain by lake sediments, is not only comparatively enriched in shocked minerals and impact glass spherules, but also contains the highest concentrations of Os, Ir, Ru, and Rh compared to other El'gygytgyn impactites. This is-to a lesser extent-the result of admixture of a mafic component, but more likely the signature of a chondritic meteoritic component. However, the highly siderophile element contribution from target material akin to the mafic blocks of the ICDP drill core to the impactites remains poorly constrained. © The Meteoritical Society, 2015. 2015 English 10869379 10.1111/maps.12455 Meteoritics and Planetary Science 50 University of Arkansas 1071-1088 Museum für Naturkunde Berlin, Leibniz Institute for Evolution and Biodiversity Science, Invalidenstraße 43, Berlin, 10115, Germany; Freie Universität Berlin, Institut für Geologische Wissenschaften, Malteser Str. 74-100, Berlin, 12249, Germany; School of Earth and Ocean Sciences, Cardiff University, Cardiff, CF10 3YE, United Kingdom; Humboldt-Universität zu Berlin, Unter den Linden 6, Berlin, 10099, Germany; Department of Lithospheric Research, Center for Earth Sciences, University of Vienna, Althanstrasse 14, Vienna, 1090, Austria; Natural History Museum, Burgring 7, Vienna, 1010, Austria 6 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84929936606&doi=10.1111%2fmaps.12455&partnerID=40&md5=1f3879ae428bc3dd6423f292ec950220 cited By 3 U. Raschke R.T. Schmitt I. Mcdonald W.U. Reimold D. Mader C. Koeberl article Wan201511 Faithfully tracing sources of sediment and then quantifying the flux of each source are the first-order basis for reconstructing paleoclimate and paleoenvironment using lake sediments. The budget of various sources contributing to lake sediment in Lake Qinghai, the largest lake on the Tibetan Plateau, is controversial. In the previous study, the flux of the dust deposition to the modern lake sediment was obtained through 2-year observations, but estimations of other sources have some uncertainties due to inadequate data. In this study our new estimations for the modern Lake Qinghai sediment using new measured data show (1) that contribution (22.1 ± 5.2 %) of the fluvial particulate matter is of second significance, only about one-third of the dust deposition, to the modern lake sediment, when its quick deposition near river mouths is not considered, (2) that lacustrine organisms contribute only 5.2 ± 1.1 % of the sediment, but account for ~70 % of the organic matter in sediment, and (3) that authigenic carbonates contribute 21.0 ± 8.6 % of the sediment and 63.6 % of the total carbonates in the lake sediment, respectively, which is due to a direct precipitation of both Ca2+ and Mg2+ in the modern Ca2+-limited lake. These quantifications are instructive to understand the particulate fluxes to sediment pools in Lake Qinghai under the present conditions and to reconstruct paleoclimate and paleoenvironment via physical and geochemical proxies using past sediments. © 2014, The Japanese Society of Limnology. Article 2015 English 14398621 10.1007/s10201-014-0434-3 Limnology 16 Springer Japan 11 – 20 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84939886590&doi=10.1007%2fs10201-014-0434-3&partnerID=40&md5=afe76c053e3e2eaea82f8ab4c138016d Cited by: 7 Dejun Wan Zhangdong Jin Fei Zhang Hongyun Chen Liumei Chen Lei Song Chao Song article Kämpf20151909 Editorial 2015 English 14373254 10.1007/s00531-015-1252-5 International Journal of Earth Sciences 104 Springer Verlag 1909 – 1912 8 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84945468911&doi=10.1007%2fs00531-015-1252-5&partnerID=40&md5=4a86ff2b0160647dc0b12f677301c522 Cited by: 0; All Open Access, Bronze Open Access Horst Kämpf Karoly Németh Jacek Puziewicz Jan Mrlina Wolfram H. Geissler article Carpenter20155273 We present results from a comprehensive laboratory study of the frictional strength and constitutive properties for all three active strands of the San Andreas Fault penetrated in the San Andreas Observatory at Depth (SAFOD). The SAFOD borehole penetrated the Southwest Deforming Zone (SDZ), the Central Deforming Zone (CDZ), both of which are actively creeping, and the Northeast Boundary Fault (NBF). Our results include measurements of the frictional properties of cuttings and core samples recovered at depths of ~2.7 km. We find that materials from the two actively creeping faults exhibit low frictional strengths (μ = ~0.1), velocity-strengthening friction behavior, and near-zero or negative rates of frictional healing. Our experimental data set shows that the center of the CDZ is the weakest section of the San Andreas Fault, with μ = ~0.10. Fault weakness is highly localized and likely caused by abundant magnesium-rich clays. In contrast, serpentine from within the SDZ, and wall rock of both the SDZ and CDZ, exhibits velocity-weakening friction behavior and positive healing rates, consistent with nearby repeating microearthquakes. Finally, we document higher friction coefficients (μ > 0.4) and complex rate-dependent behavior for samples recovered across the NBF. In total, our data provide an integrated view of fault behavior for the three active fault strands encountered at SAFOD and offer a consistent explanation for observations of creep and microearthquakes along weak fault zones within a strong crust. ©2015. American Geophysical Union. All Rights Reserved. 2015 English 21699313 10.1002/2015JB011963 Journal of Geophysical Research: Solid Earth 120 Blackwell Publishing Ltd 5273-5289 Istituto Nazionale di Geofisica e Vulcanologia, Rome, Italy; Department of Geosciences and Energy, Institute Center for Geomechanics, Geofluids, and Geohazards, Pennsylvania State University, University Park, PA, United States 7 active fault; creep; fault slip; fault zone; friction; microearthquake; San Andreas Fault, California; San Andreas; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-84939214772&doi=10.1002%2f2015JB011963&partnerID=40&md5=a9c0d6ff3c99ae78171feca0063fb26a cited By 64 B.M. Carpenter D.M. Saffer C. Marone article Morris2015206 2015 English 19418264 10.1130/L395.1 Lithosphere 7 Geological Society of America 206-206 2 Caledonian orogeny; detrital deposit; foreland basin; geochronology; lithosphere; lithostratigraphy; orogenic belt; zircon, Arctic; Greenland https://www.scopus.com/inward/record.uri?eid=2-s2.0-84928232364&doi=10.1130%2fL395.1&partnerID=40&md5=79f6a0a6e4e11daabbc38ccd79df4127 cited By 0 G.A. Morris C.L. Kirkland V. Pease article Farber2015150 In recent years, the role of Archaean seawater and hydrothermal fluid in the extensive silicification of Palaeoarchaean volcano-sedimentary successions has been a matter of considerable debate. In an attempt to constrain the conditions of silica precipitation, and the sources and chemical composition of the interacting fluids, we used fluid inclusion microthermometry, bulk crush-leach and oxygen isotope analyses of chert and quartz veins in silicified komatiites and sediments from the Barberton greenstone belt, South Africa. Chert vein margins consist of microcrystalline quartz and carbonaceous matter, whereas the vein centres are often filled with macrocrystalline quartz that contains abundant fluid inclusions.Oxygen isotope ratios of vein chert and macrocrystalline quartz vary from 18 to 21‰, with the macrocrystalline quartz having slightly higher δ18O values (0.7±0.3‰). The data are consistent with silica precipitation during low-temperature (≤100°C) hydrothermal processes on the Archaean seafloor. Macrocrystalline quartz contains homogeneous 2-phase (L+V) inclusions at room temperature with a relatively constant vapour fraction. The inclusions have a salinity of 3-11wt.% NaCl equiv. and homogenisation temperatures (Th) of 150-200°C. Whereas some of the inclusions form intragranular fluid inclusion clusters that appear to be primary, other inclusions form transgranular fluid inclusion trails and are clearly secondary. Both types of inclusions share the same microthermometric characteristics, indicating that fluid entrapment occurred during a later metamorphic event and not near the seafloor. The event likely coincided with regional deformation and metamorphism at 3.23Ga. Chlorite thermometry from vein host rocks reveals peak conditions of ~257±31°C. In conjunction with microthermometry, the data correspond to a crustal depth of 3-6km. A secondary origin of fluid inclusions is also consistent with the Cl/Br, Na/Cl and Na/K ratios of the macrocrystalline veins, which are similar to those found in metamorphic quartz veins. The fluid inclusions thus do not provide information on the conditions and temperatures during chert formation. While the fluids potentially carry the geochemical signature of modified Archaean seawater (i.e. hydrothermal fluid), characterised by low Cl/Br and Na/K ratios, and low Mg-contents, the fluid composition was likely modified during regional metamorphism. © 2015 Elsevier B.V. Article 2015 English 03019268 10.1016/j.precamres.2015.05.020 Precambrian Research 266 Elsevier 150 – 164 Barberton Greenstone Belt; Archean; chert; deformation mechanism; fluid inclusion; hydrothermal alteration; hydrothermal fluid; isotopic ratio; oceanic crust; oxygen isotope; paleoceanography; quartz vein; seawater; silicification https://www.scopus.com/inward/record.uri?eid=2-s2.0-84930674700&doi=10.1016%2fj.precamres.2015.05.020&partnerID=40&md5=b83af565e37104e974f5037738f97ec4 Cited by: 16 Katja Farber Annika Dziggel F. Michael Meyer Walter Prochaska Axel Hofmann Chris Harris article Eccles20155736 Fault Zone Guided Waves (FZGWs) have been observed for the first time within New Zealand's transpressional continental plate boundary, the Alpine Fault, which is late in its typical seismic cycle. Ongoing study of these phases provides the opportunity to monitor interseismic conditions in the fault zone. Distinctive dispersive seismic codas (~7-35Hz) have been recorded on shallow borehole seismometers installed within 20m of the principal slip zone. Near the central Alpine Fault, known for low background seismicity, FZGW-generating microseismic events are located beyond the catchment-scale partitioning of the fault indicating lateral connectivity of the low-velocity zone immediately below the near-surface segmentation. Initial modeling of the low-velocity zone indicates a waveguide width of 60-200m with a 10-40% reduction in S wave velocity, similar to that inferred for the fault core of other mature plate boundary faults such as the San Andreas and North Anatolian Faults. © 2015. American Geophysical Union. All Rights Reserved. 2015 English 00948276 10.1002/2015GL064208 Geophysical Research Letters 42 5736-5743 School of Environment, University of Auckland, Auckland, New Zealand; Department of Mathematics, University of Auckland, Auckland, New Zealand; Department of Physics, University of Auckland, Auckland, New Zealand; International Earth Sciences IESE Ltd., Auckland, New Zealand; School of Geography, Environment and Earth Sciences, Victoria University of Wellington, Wellington, New Zealand; GNS Science, Lower Hutt, New Zealand 14 Catchments; Guided electromagnetic wave propagation; Seismology; Shear waves, Alpine Faults; Drilling projects; Fault zone; Low velocity zones; Microseismic events; North Anatolian Fault; Shallow boreholes; Waveguide widths, Faulting, catchment; fault zone; plate boundary; S-wave; segmentation; seismograph; seismology; slip; slip rate, Anatolia; California; New Zealand; San Andreas; Turkey; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-84938966297&doi=10.1002%2f2015GL064208&partnerID=40&md5=e786fa3cb8cc7d8fab428422d3d7cfcf cited By 28 J.D. Eccles A.K. Gulley P.E. Malin C.M. Boese J. Townend R. Sutherland article Toy2015155 The first phase of the Deep Fault Drilling Project (DFDP-1) yielded a continuous lithological transect through fault rock surrounding the Alpine fault (South Island, New Zealand). This allowed micrometer-to decimeter-scale variations in fault rock lithology and structure to be delineated on either side of two principal slip zones intersected by DFDP-1A and DFDP-1B. Here, we provide a comprehensive analysis of fault rock lithologies within 70 m of the Alpine fault based on analysis of hand specimens and detailed petrographic and petrologic analysis. The sequence of fault rock lithologies is consistent with that inferred previously from outcrop observations, but the continuous section afforded by DFDP-1 permits new insight into the spatial and genetic relationships between different lithologies and structures. We identify principal slip zone gouge, and cataclasite-series rocks, formed by multiple increments of shear deformation at up to coseismic slip rates. A 20-30-m-thick package of these rocks (including the principal slip zone) forms the fault core, which has accommodated most of the brittle shear displacement. This deformation has overprinted ultramylonites deformed mostly by grain-size-insensitive dislocation creep. Outside the fault core, ultramylonites contain low-displacement brittle fractures that are part of the fault damage zone. Fault rocks presently found in the hanging wall of the Alpine fault are inferred to have been derived from protoliths on both sides of the present-day principal slip zone, specifically the hanging-wall Alpine Schist and footwall Greenland Group. This implies that, at seismogenic depths, the Alpine fault is either a single zone of focused brittle shear that moves laterally over time, or it consists of multiple strands. Ultramylonites, cataclasites, and fault gouge represent distinct zones into which deformation has localized, but within the brittle regime, particularly, it is not clear whether this localization accompanies reductions in pressure and temperature during exhumation or whether it occurs throughout the seismogenic regime. These two contrasting possibilities should be a focus of future studies of fault zone architecture. © 2015 Geological Society of America. 2015 English 19418264 10.1130/L395.1 Lithosphere 7 Geological Society of America 155-173 Department Of Geology, University Of Otago, P.O. Box 56, Dunedin, 9054, New Zealand; Geological Sciences, University Of Canterbury, Private Bag 4800, Christchurch, 8140, New Zealand; GNS Science, P.O. Box 30-368, Lower Hutt, 5040, New Zealand; School Of Geography, Environment, and Earth Sciences, Victoria University Of Wellington, P.O. Box 600, Wellington, 6140, New Zealand; School Of Environmental Sciences, University Of Liverpool, Liverpool, L69 3GP, United Kingdom; Ocean and Earth Science, National Oceanography Centre Southampton, University Of Southampton, Waterfront Campus, European Way, Southampton, SO14 3ZH, United Kingdom; Istituto Nazionale Di Geofisica E Vulcanologia, Rome 1 Section, Via Di Vigna Murata, 605, Rome, 00143, Italy 2 Brittle fracture; Creep; Lithology; Rock drilling; Rocks, Comprehensive analysis; Fault zone architecture; Genetic relationships; Grain size insensitive dislocation creeps; Pressure and temperature; Seismogenic regimes; Shear displacement; South Island , New Zealand, Structural geology, alpine environment; cataclasite; deep drilling; fault zone; lithology; outcrop; petrography, Alpine Fault Zone; New Zealand; South Island https://www.scopus.com/inward/record.uri?eid=2-s2.0-84928235643&doi=10.1130%2fL395.1&partnerID=40&md5=e9e507317ce93707c40dea9cff6cda17 cited By 65 V.G. Toy C.J. Boulton R. Sutherland J. Townend R.J. Norris T.A. Little D.J. Prior E. Mariani D. Faulkner C.D. Menzies H. Scott B.M. Carpenter article Cukur2015329 In Lake Van of eastern Turkey, the fourth largest soda lake in the world, high-resolution subbottom profiles and bathymetric data acquired in 2004 and 2012 revealed several hundreds of topographic mounds in shallow waters (<130 m) off the historical town of Adilcevaz in the northern lake sector. These structures are characterized by strong top reflections of transparent internal character, and are 10–300 m wide and 0.5–20 m high. Consistent with previous work, they are interpreted as carbonate mounds formed by precipitation from CO2-rich groundwater discharge into the highly alkaline lake. Their age remains to be determined but their alignment along faults suggests tectonic control on their growth. Several sublacustrine channel networks were observed on the eastern shelf of the lake, which connects with onshore rivers. The channels are up to 500 m wide and 20 m deep, and plausibly were formed by fluvial processes during the major lake level drop reported to have occurred by 14 ka in earlier publications. Erosion is common on the channel walls flanked by levees. The channels are presently inactive or abandoned. At a water depth of 100 m, they all merge into a single larger channel; this channel has a sinuous course initially trending southwestward and then northwestward at a water depth of 130 m. Numerous closely spaced small channels (~10–200 m wide, 1–10 m deep) are also seen on the eastern lacustrine shelf, interpreted as denditric and parallel channel systems formed during lake level fall terminating at ~14 ka. Bathymetric data provide evidence of numerous sublacustrine canyons on the western slope of the lake’s northern basin, most likely remnants of relict rivers formed during this lowstand. © 2015, Springer-Verlag Berlin Heidelberg. 2015 English 02760460 10.1007/s00367-015-0410-x Geo-Marine Letters 35 Springer Verlag 329-340 Petroleum and Marine Research Division, Korea Institute of Geoscience and Mineral Resources (KIGAM), Daejeon, 305-350, South Korea; Institute of Geosciences, Kiel University, Otto-Hahn-Platz 1, Kiel, 24118, Germany; EMCOL and Department of Geological Engineering, Istanbul Technical University, Maslak, Istanbul, 34469, Turkey; Department of Geological Engineering, Van Yüzüncü Yıl University, Van, 65080, Turkey 5 Bathymetry; Channel flow; Groundwater; Hydrographic surveys, Bathymetric data; Carbonate mounds; Chirp sub bottoms; Ground water discharge; Multibeam echo sounder; Parallel channel; Sub-bottom profiles; Tectonic control, Lakes, carbonate platform; fluvial process; lacustrine environment; levee; multibeam sonar; profiler; shallow water, Lake Van; Turkey https://www.scopus.com/inward/record.uri?eid=2-s2.0-84941174888&doi=10.1007%2fs00367-015-0410-x&partnerID=40&md5=71a56fda93fcf871ac1c7f2fe75981c5 cited By 18 D. Cukur S. Krastel M.N. Çağatay E. Damcı A.F. Meydan S.-P. Kim article Fowler201547 We describe the lithology and present spatially resolved geochemical analyses of samples from the hydrothermally altered Iceland Deep Drilling Project (IDDP) drill core RN-17B. The 9.3m long RN-17B core was collected from the seawater-dominated Reykjanes geothermal system, located on the Reykjanes Peninsula, Iceland. The nature of fluids and the location of the Reykjanes geothermal system make it a useful analog for seafloor hydrothermal processes, although there are important differences. The recovery of drill core from the Reykjanes geothermal system, as opposed to drill cuttings, has provided the opportunity to investigate evolving geothermal conditions by utilizing in-situ geochemical techniques in the context of observed paragenetic and spatial relationships of alteration minerals. The RN-17B core was returned from a vertical depth of ~2560m and an in-situ temperature of ~345°C. The primary lithologies are basaltic in composition and include hyaloclastite breccia, fine-grained volcanic sandstone, lithic breccia, and crystalline basalt. Primary igneous phases have been entirely pseudomorphed by calcic plagioclase+magnesium hornblende+chlorite+titanite+albitized plagioclase+vein epidote and sulfides. Despite the extensive hydrothermal metasomatism, original textures including hyaloclastite glass shards, lithic clasts, chilled margins, and shell-fragment molds are superbly preserved. Multi-collector LA-ICP-MS strontium isotope ratio (87Sr/86Sr) measurements of vein epidote from the core are consistent with seawater as the dominant recharge fluid. Epidote-hosted fluid inclusion homogenization temperature and freezing point depression measurements suggest that the RN-17B core records cooling through the two-phase boundary for seawater over time to current in-situ measured temperatures. Electron microprobe analyses of hydrothermal hornblende and hydrothermal plagioclase confirm that while alteration is of amphibolite-grade, it is in disequilibrium and the extent of alteration is dependent upon protolith type and water/rock ratio. Alteration in the RN-17B core bares many similarities to that of Type II basalts observed in Mid-Atlantic Ridge samples. © 2015 Elsevier B.V. 2015 English 03770273 10.1016/j.jvolgeores.2015.06.009 Journal of Volcanology and Geothermal Research 302 Elsevier 47-63 Department of Earth and Planetary Sciences, University of California, DavisCA 95616, United States; Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA 94550, United States; HS Orka, hf, Reykjanesbaer, Iceland Analytical geochemistry; Basalt; Core drilling; Drills; Electron probe microanalysis; Feldspar; Geochemistry; Geothermal fields; Isotopes; Lithology; Microanalysis; Mineralogy; Rock drilling; Rocks; Seawater; Silicate minerals; Strontium, Drill core; Epidote; Geothermal; Hydrothermal alterations; Icelands; Reykjanes, Core samples, deep drilling; epidote; geochemistry; geothermal system; hydrothermal alteration; lithology; paragenesis; seawater, Iceland; Reykjanes Peninsula https://www.scopus.com/inward/record.uri?eid=2-s2.0-84933073486&doi=10.1016%2fj.jvolgeores.2015.06.009&partnerID=40&md5=d6e1cbaadb3794b302b5d1a518eabcb2 cited By 15 A.P.G. Fowler R.A. Zierenberg P. Schiffman N. Marks G.O. Frileifsson article Neugebauer20151358 Laminated lake sediments from the Dead Sea basin provide high-resolution records of climatic variability in the eastern Mediterranean region, which is especially sensitive to changing climatic conditions. In this study, we aim on detailed reconstruction of climatic fluctuations and related changes in the frequency of flood and dust deposition events at ca. 3300 and especially at 2800 cal. yr BP from high-resolution sediment records of the Dead Sea basin. A ca. 4-m-thick, mostly varved sediment section from the western margin of the Dead Sea (DSEn – Ein Gedi profile) was analysed and correlated to the new International Continental Scientific Drilling Program (ICDP) Dead Sea Deep Drilling Project core 5017-1 from the deep basin. To detect even single event layers, we applied a multi-proxy approach of high-resolution microscopic thin section analyses, micro-X-ray fluorescence (µ-XRF) element scanning and magnetic susceptibility measurements, supported by grain size data and palynological analyses. Based on radiocarbon and varve dating, two pronounced dry periods were detected at ~3500–3300 and ~3000–2400 cal. yr BP which are differently expressed in the sediment records. In the shallow-water core (DSEn), the older dry period is characterised by a thick sand deposit, whereas the sedimentological change at 2800 cal. yr BP is less pronounced and characterised mainly by an enhanced frequency of coarse detrital layers interpreted as erosion events. In the 5017-1 deep-basin core, both dry periods are depicted by halite deposits. The onset of the younger dry period coincides with the Homeric Grand Solar Minimum at ca. 2800 cal. yr BP. Our results suggest that during this period, the Dead Sea region experienced an overall dry climate, superimposed by an increased occurrence of flash floods caused by a change in synoptic weather patterns. © The Author(s) 2015. 2015 English 09596836 10.1177/0959683615584208 Holocene 25 SAGE Publications Ltd 1358-1371 Section 5.2 – Climate Dynamics and Landscape Evolution, GFZ German Research Centre for Geosciences Potsdam, Germany; Dr. Strauss Department of Marine Geosciences, Leon H. Charney School of Marine Sciences, University of Haifa, Israel; Graduate School of Environmental Studies, Nagoya University, Japan; Steinmann Institute of Geology, Mineralogy and Paleontology, University of Bonn, Germany 8 dust; extreme event; flash flood; Holocene; lacustrine deposit; marine sediment; microfacies; paleoclimate; palynology; temporal period; varve, Dead Sea; Mediterranean Region https://www.scopus.com/inward/record.uri?eid=2-s2.0-84936804520&doi=10.1177%2f0959683615584208&partnerID=40&md5=8ee7ac11b8e3a6f5369fa1d15a62d72e cited By 43 I. Neugebauer A. Brauer M.J. Schwab P. Dulski U. Frank E. Hadzhiivanova H. Kitagawa T. Litt V. Schiebel N. Taha N.D. Waldmann article osti_1236394 2014 2 10.2172/1236394 Report to Department of Energy Geothermal Technology Office https://www.osti.gov/biblio/1236394 John W. Shervais James P. Evans Lee M. Liberty David D. Blackwell article Kietäväinen2014159 Noble gas residence times of saline groundwaters from the 2516m deep Outokumpu Deep Drill Hole, located within the Precambrian crystalline bedrock of the Fennoscandian Shield in Finland, are presented. The accumulation of radiogenic (4He, 40Ar) and nucleogenic (21Ne) noble gas isotopes in situ together with the effects of diffusion are considered. Fluid samples were collected from depths between 180 and 2480m below surface, allowing us to compare the modelled values with the measured concentrations along a vertical depth profile. The results show that while the concentrations in the upper part are likely affected by diffusion, there is no indication of diffusive loss at or below 500m depth. Furthermore, no mantle derived gases were found unequivocally. Previous studies have shown that distinct vertical variation occurs both in geochemistry and microbial community structuring along the drill hole, indicating stagnant waters with no significant exchange of fluids between different fracture systems or with surface waters. Therefore in situ accumulation is the most plausible model for the determination of noble gas residence times. The results show that the saline groundwaters in Outokumpu are remarkably old, with most of the samples indicating residence times between ~20 and 50Ma. Although being first order approximations, the ages of the fluids clearly indicate that their formation must predate more recent events, such as Quaternary glaciations. Isolation within the crust since the Eocene-Miocene epochs has also direct implications to the deep biosphere found at Outokumpu. These ecosystems must have been isolated for a long time and thus very likely rely on energy and carbon sources such as H2 and CO2 from groundwater and adjacent bedrock rather than from the ground surface. © 2014 Elsevier Ltd. Article 2014 English 00167037 10.1016/j.gca.2014.09.012 Geochimica et Cosmochimica Acta 145 Elsevier Ltd 159 – 174 Baltic Shield; East European Craton; Finland; Outokumpu; Pohjois-Karjala; bedrock; carbon dioxide; diffusion; groundwater; hydrochemistry; hydrogen; isotopic composition; noble gas; residence time https://www.scopus.com/inward/record.uri?eid=2-s2.0-84908361183&doi=10.1016%2fj.gca.2014.09.012&partnerID=40&md5=fd4d141c3d16769d7903030f81ff7fa2 Cited by: 32; All Open Access, Green Open Access Riikka Kietäväinen Lasse Ahonen Ilmo T. Kukkonen Samuel Niedermann Thomas Wiersberg conference Yamamoto20141802 In March 2013, the world's first field trial of gas production from marine methane hydrate deposits was conducted in the Daini Atsumi Knoll area of the Eastern Nankai Trough off the Pacific coast of Japan as a process to bring gas hydrates under seafloor to valuable energy resource. The technique used to dissociate the ice-like material was "depressurization method" that had been applied in the previous production test in Mallik site, the Northwest Territories, Canada in 2007-2008. Japan Oil, Gas and Metals National Corporation (JOGMEC) as a part of MH21, the Research Consortium for Methane Hydrate Resources in Japan planed and supervised the project with the funding of the Ministry of Economy, Trade and Industry (METI), and scientific supports from the National Institute of Advance Industrial Science and Technology (AIST). One production well with two monitoring boreholes were drilled in the test site for the test. Along with the flow test operation, intensive data acquisition program was planned and implemented to understand behavior of methane hydrate dissociation-bearing sediments against depressurization. To realize high degree of drawdown in relatively shallow formation below deepwater, several downhole devices were designed and installed. The flow test started in the morning of March 12 and lasted until severe sand production forced to terminate the operation six days later. During the stable production term, gas flow rate was approximately 20,000m3 under atmospheric condition, and gas liquid ratio was larger than 100. A lot of data including formation temperatures, fluid pressure and temperature, and physical property changes in the formation were obtained. The data taken are under studies to verify applicability of the depressurization technique as a methane hydrate production technologies. Copyright 2014, Offshore Technology Conference. 2014 English 9781632665287; 9781632663870 01603663 10.4043/25243-ms Proceedings of the Annual Offshore Technology Conference 3 Offshore Technology Conference 1802-1812 Japan Oil, Gas and Metals National Corporation, Japan; Japan Petroleum Exploration Co. Ltd., Japan; Japan Drilling Company, Japan; Schlumberger KK, Japan Atmospheric movements; Data acquisition; Energy resources; Flow of gases; Gases; Hydration; Industrial research; Methane; Offshore oil well production; Offshore oil wells; Offshore technology; Software testing, Acquisition programs; Atmospheric conditions; Depressurization methods; Formation temperature; Methane hydrate dissociation; Methane hydrate productions; Ministry of economy , trade and industries; Science and Technology, Gas hydrates https://www.scopus.com/inward/record.uri?eid=2-s2.0-84945188738&doi=10.4043%2f25243-ms&partnerID=40&md5=9f1bc5354865a9619100c7d29db89564 cited By 240 K. Yamamoto Y. Terao T. Fujii T. Ikawa M. Seki M. Matsuzawa T. Kanno article Tomonaga2014117 Sediment samples acquired in 2010 from the long cores of the International Continental Scientific Drilling Program (ICDP) PaleoVan drilling project on Lake Van for noble-gas analysis in the pore water allow determination of the local terrestrial He-gradient as a function of depth within a sediment column of more than 200m. These measurements yield first insights into the physical transport mechanisms of terrigenic He through the uppermost part of unconsolidated lacustrine sediments overlying the continental crust.In line with our previous work on the spatial distribution of the terrigenic He release into Lake Van, we identify a high He concentration gradient in the uppermost 10m of the sediment column. The He concentration gradient decreases below this depth down to approx. 160. m following in general the expectations of the modelling of radiogenic He production and transport in a sediment column with homogeneous fluid transport properties. Overall the in-situ radiogenic He production due to the decay of U and Th in the mineral phases of the sediments accounts for about 80% of the He accumulation. At approx. 190. m we observe a very high He concentration immediately below a large lithological unit characterised by strong deformations. We speculate that this local enrichment is the result of the lower effective diffusivities in the pore space that relate to the abrupt depositional history of this deformed unit. This particular lithological unit seems to act as a barrier that limits the transport of solutes in the pore space and hence might "trap" information on the past geochemical conditions in the pore water of Lake Van.The dissolved concentrations of atmospheric noble gases in the pore waters of the ICDP PaleoVan cores are used to geochemically reconstruct salinity on the time scale of 0-55kaBP. Higher salinities in the pore water at a depth of about 20m suggest a significantly lower lake level of Lake Van in the past. © 2014 Elsevier Ltd. 2014 English 02773791 10.1016/j.quascirev.2014.09.005 Quaternary Science Reviews 104 Elsevier Ltd 117-126 Eawag, Swiss Federal Institute of Aquatic Science and Technology, Water Resources and Drinking Water, Duebendorf, Switzerland; Department of Geological Engineering, Yuzuncu Yil University, Van, Turkey; Institute of Biogeochemistry and Pollutant Dynamics, Swiss Federal Institute of Technology, Zurich, Switzerland; Institute of Geochemistry and Petrology, Swiss Federal Institute of Technology, Zurich, Switzerland Inert gases; Infill drilling; Lakes; Lithology; Mineral industry; Solute transport; Water, Concentration gradients; Continental scientific drillings; Deep drilling; Dissolved concentrations; ICDP; Palaeo-salinity; Palaeoenvironmental reconstruction; PaleoVan, Sediments, continental crust; deep drilling; helium; lacustrine deposit; lithology; mineral; noble gas; paleoenvironment; paleosalinity; porewater; reconstruction; sediment analysis; sediment chemistry; solute transport, Lake Van; Turkey https://www.scopus.com/inward/record.uri?eid=2-s2.0-84909580967&doi=10.1016%2fj.quascirev.2014.09.005&partnerID=40&md5=393326873e0c2c87ae342bddfdefd662 cited By 19 Y. Tomonaga M.S. Brennwald A.F. Meydan R. Kipfer conference Popov20143263 The present work summarizes the results of analysis of unique experimental data on vertical heat flow variations in different geological structures obtained from 15 scientific supper-deep and deep boreholes drilled to the depths of 1600-12 262 m within Russian and ICDP programs. The new workflow was applied for the heat flow estimation which is based on (1) precise and detailed thermal conductivity measurements on more than 30 000 cores with the new emerging technologies, (2) usage of more than 100 equilibrium and non-equilibrium temperature logs, and (3) determination of conductive heat flow component within 20-100 m intervals along every borehole studied. The data on conductive heat flow variations provides an estimate of vertical variations in the convective heat flow component. The latter reflects the information on variations in reservoir and formation properties and heat- and mass transfer processes in reservoirs and formations. It was established that a conductive component of the heat flow varies between 70 and 100% for the boreholes studied with essential (up to 100%) increase in heat flow within upper depth intervals of 2-4 km in some cases. Terrestrial heat flow values established from the measurements in deep and super-deep boreholes exceed the previous experimental heat flow estimates by 30...130% depending on a region of drilling. During the previous estimates the heat flow values were obtained from the measurements in shallow boreholes and heat flow was determined from averaging temperature gradient and thermal conductivity along boreholes. The established heat flow variations play an important role in the improvement of reliability of basin and petroleum system modeling and prediction of temperatures below the borehole depths. The use of calibrated heat flow distributions is shown to increase the confidence of such studies. Copyright © 2014, International Petroleum Technology Conference. 2014 10.2523/iptc-18095-ms Society of Petroleum Engineers - International Petroleum Technology Conference 2014, IPTC 2014 - Innovation and Collaboration: Keys to Affordable Energy 4 3263-3274 Schlumberger, Venezuela https://www.scopus.com/inward/record.uri?eid=2-s2.0-84934287259&doi=10.2523%2fiptc-18095-ms&partnerID=40&md5=b934f12a34f138fe85239cd848770b2a cited By 1 Yu. Popov E. Popov D. Miklashevskiy D. Korobkov article Cvetkoska2014313 Several taxa from the genus Cyclotella observed in two ancient sister lakes, Prespa and Ohrid were studied and compared to the regionally common species Cyclotella ocellata. Two new species are described from Lake Prespa and additionally Cyclotella thienemannii var. minuscula from Lake Ohrid is formally transferred to Cyclotella minuscula (Jurilj) Cvetkoska stat. nov. Cyclotella paraocellata sp. nov. is compared to C. ocellata and is characterized by a large morphological variability in the fossil and recent diatom assemblages. Cyclotella prespanensis sp. nov. is described and distinguished as a separate taxon by its valve size range, colliculate central area, stria density and number and position of marginal fultoportulae and rimoportulae. The investigation reveals C. ocellata and C. minuscula as the only taxa of the genus Cyclotella present in fossil and contemporary diatom assemblages from both Lake Ohrid and Lake Prespa. © 2014 J. Cramer in Gebr. Borntraeger Verlagsbuchhandlung, Stuttgart. Germany. Article 2014 English 00295035 10.1127/0029-5035/2014/0154 Nova Hedwigia 98 Gebruder Borntraeger Verlagsbuchhandlung 313 – 340 3-4 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84898038965&doi=10.1127%2f0029-5035%2f2014%2f0154&partnerID=40&md5=386b12212bce88b724c2d8c67ae512a3 Cited by: 21 Aleksandra Cvetkoska Paul B. Hamilton Nadja Ognjanova-Rumenova Zlatko Levkov article Çağatay201497 Sedimentary, geochemical and mineralogical analyses of the ICDP cores recovered from the Northern Basin (NB) of Lake Van provide evidence of lake level and climatic changes related to orbital and North Atlantic climate system over the last 90ka. High lake levels are generally observed during the interglacial and interstadial periods, which are marked by deposition of varved sediments with high total organic carbon (TOC), total inorganic carbon (TIC), low detrital influx (high Ca/F) and high δ18O and δ13C values of authigenic carbonate. During the glacial and stadial periods of 71-58kaBP (Marine Isotope Stage 4, MIS4) and end of last glaciation-deglaciation (30-14.5kaBP; MIS3) relatively low lake levels prevailed, and grey homogeneous to faintly laminated clayey silts were deposited at high sedimentation and low organic productivity rates.Millennial-scale variability of the proxies during 60-30kaBP (MIS3 is correlated with the Dansgaard-Oeschger (D-O)) and Holocene abrupt climate events in the Atlantic. These events are characterized by laminated sediments, with high TOC, TIC, Ca/Fe, δ18O and δ13C values. The Lake Van NB records correlate well in the region with the climate records from the lakes Zeribar and Urmia in Iran and the Sofular Cave in NW Anatolia, but are in general in anti-phase to those from the Dead Sea Basin (Lake Lisan) in the Levant. The relatively higher δ18O values (0 to-0.4‰) for the interglacial and interstadial periods in the Lake Van NB section are due to the higher temperature and seasonality of precipitation and higher evaporation, whereas the lower values (-0.8 to-2‰) during the glacial and stadial periods are caused mainly by relative decrease in both temperature and seasonality of precipitation. The high δ18O values (up to 4.2‰) during the Younger Dryas, together with the presence of dolomite and low TOC contents, supports evaporative conditions and low lake level. A gradual decrease in the δ18O values from an average of-0.4‰ during the humid early Holocene to an average of-3.5‰ during the more arid late Holocene suggests an increasing contribution of winter precipitation. The changes in the seasonality of precipitation in eastern Anatolia are probably caused by changes in the temperatures of North Atlantic and Mediterranean and in the strength of Siberian High. © 2014 Elsevier Ltd. 2014 English 02773791 10.1016/j.quascirev.2014.09.027 Quaternary Science Reviews 104 Elsevier Ltd 97-116 Istanbul Technical University, Eastern Mediterranean Centre for Oceanography and Limnology (EMCOL), Ayazağa Kampusu, Maslak, Istanbul, 34469, Turkey; Istanbul Technical University, Faculty of Mines, Geological Engineering Department, Turkey; Istanbul Technical University, Eurasia Institute of Earth Sciences, Turkey; Eawag, Swiss Federal Institute of Aquatic Science and Technology, Department of Surface Waters Research and Management, Switzerland; ETH, Geological Institute, Zurich Universitaetsstrasse 5, Zurich, 8092, Switzerland; Firat University, Department of Geological Engineering, Elaziğ, Turkey Climate record; ICDP PaleoVan; Lake levels; Lake vans; Multproxy analyses; Northern basins, authigenesis; climate variation; Dansgaard-Oeschger cycle; Holocene; interstadial; lake level; marine isotope stage; paleoclimate; precipitation (climatology); proxy climate record, Anatolia; Atlantic Ocean; Iran; Kordestan; Lake Urmia; Lake Van; Lake Zeribar; Levant; Mediterranean Region; Turkey https://www.scopus.com/inward/record.uri?eid=2-s2.0-84909599486&doi=10.1016%2fj.quascirev.2014.09.027&partnerID=40&md5=45d48abb11b99b381346a3ee8fb940b6 cited By 73 M.N. Çağatay N. Öğretmen E. Damci M. Stockhecke Ü. Sancar K.K. Eriş S. Özeren article cp-10-1381-2014 The 3.6 Ma sediment record of Lake El'gygytgyn/NE Russia, Far East Russian Arctic, represents the longest continuous climate archive of the terrestrial Arctic. Its elemental composition as determined by X-ray fluorescence scanning exhibits significant changes since the mid-Pliocene caused by climate-driven variations in primary production, postdepositional diagenetic processes, and lake circulation as well as weathering processes in its catchment. <br><br> During the mid-to late Pliocene, warmer and wetter climatic conditions are reflected by elevated Si/Ti ratios, indicating enhanced diatom production in the lake. Prior to 3.3 Ma, this signal is overprinted by intensified detrital input from the catchment, visible in maxima of clastic-related proxies, such as K. In addition, calcite formation in the early lake history points to enhanced Ca flux into the lake caused by intensified weathering in the catchment. A lack of calcite deposition after ca. 3.3 Ma is linked to the development of permafrost in the region triggered by cooling in the mid-Pliocene. After ca. 3.0 Ma the elemental data suggest a gradual transition to Pleistocene-style glacial-interglacial cyclicity. In the early Pleistocene, the cyclicity was first dominated by variations on the 41 kyr obliquity band but experienced a change to a 100 kyr eccentricity dominance during the middle Pleistocene transition (MPT) at ca. 1.2-0.6 Ma. This clearly demonstrates the sensitivity of the Lake El'gygytgyn record to orbital forcing. A successive decrease of the baseline levels of the redox-sensitive Mn/Fe ratio and magnetic susceptibility between 2.3 and 1.8 Ma reflects an overall change in the bottom-water oxygenation due to an intensified occurrence of pervasive glacial episodes in the early Pleistocene. The coincidence with major changes in the North Pacific and Bering Sea paleoceanography at ca. 1.8 Ma implies that the change in lake hydrology was caused by a regional cooling in the North Pacific and the western Beringian landmass and/or changes in the continentality. Further increases in total organic carbon and total nitrogen content after ca. 1.6 Ma are attributed to reduced organic matter decay in the sediment during prolonged anoxic periods. This points to more extensive periods of perennial ice coverage, and thus, to a progressive shifts towards more intense peak glacial periods. In the course of the Pleistocene glacial-interglacial sequence eight so-called "super-interglacials" occur. Their exceptionally warm conditions are reflected by extreme Si/Ti peaks accompanied by lows in Ti, K, and Fe, thus indicating extraordinary high lake productivity. © 2014 Author(s). 2014 English 18149324 10.5194/cp-10-1381-2014 Climate of the Past 10 Copernicus GmbH 1381-1399 University of Cologne, Institute of Geology and Mineralogy, Cologne, Germany; Russian Academy of Sciences, Northeast Interdisciplinary Scientific Research Institute, Magadan, Russian Federation; Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences, Potsdam, Germany; University of Massachusetts, Department of Geosciences, United States 4 https://cp.copernicus.org/articles/10/1381/2014/ cited By 44 V. Wennrich P. S. Minyuk V. Borkhodoev A. Francke B. Ritter N. R. Nowaczyk M. A. Sauerbrey J. Brigham-Grette M. Melles article Schwamborn20141109 The continuous sediment record from Lake El'gygytgyn in the northeastern Eurasian Arctic spans the last 3.6 Ma and for much of this time permafrost dynamics and lake level changes have likely played a crucial role for sediment delivery to the lake. Changes in the ground-ice hydrochemical composition (δ18O, δD, pH, electrical conductivity, Na+, Mg2+, Ca2+, K+, HCO3-, Cl-, SO4-) of a 141 m long permafrost record from the western crater plain are examined to reconstruct repeated periods of freeze and thaw at the lake edge. Stable water isotope and major ion records of ground ice in the permafrost reflect both a synsedimentary palaeo-precipitation signal preserved in the near-surface permafrost (0.0-9.1 m core depth) and a post-depositional record of thawing and refreezing in deeper layers of the core (9.1-141.0 m core depth). These lake marginal permafrost dynamics were controlled by lake level changes that episodically flooded the surfaces and induced thaw in the underlying frozen ground. During times of lake level fall these layers froze over again. At least three cycles of freeze and thaw are identified and the hydrochemical data point to a vertical and horizontal talik refreezing through time. Past permafrost thaw and freeze may have destabilised the basin slopes of Lake El'gygytgyn and this has probably promoted the release of mass movements from the lake edge to the deeper basin as known from frequently occurring turbidite layers in the lake sediment column. © Author(s) 2014. 2014 English 18149324 10.5194/cp-10-1109-2014 Climate of the Past 10 Copernicus GmbH 1109-1123 Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Telegrafenberg A43, 14473 Potsdam, Germany; Arctic and Antarctic Research Institute, Bering Street 38, 199397 St. Petersburg, Russian Federation; St. Petersburg State University, 10 line V.O., 33, 199178 St. Petersburg, Russian Federation 3 data set; freeze-thaw cycle; lacustrine deposit; mass movement; metal; permafrost; precipitation (climatology); sediment analysis; turbidity, Chukchi; Elgygytgyn Lake; Russian Federation https://www.scopus.com/inward/record.uri?eid=2-s2.0-84902292845&doi=10.5194%2fcp-10-1109-2014&partnerID=40&md5=3284db02fbf5015f4e2da9f16fb6d44d cited By 8 G. Schwamborn H. Meyer L. Schirrmeister G. Fedorov article VanBree201489 We studied the distribution of long-chain alkenes (n-C23 to n-C31) in well-dated sediments from Lake Challa, a deep crater lake near Mt. Kilimanjaro in equatorial East Africa, to reveal signatures of palaeo-environmental and palaeo-climatic changes affecting the production of these compounds during the last 25kyr. The apolar fractions of organic sediment extracts dated to the last 16kyr showed an unusual dominance of δ13C-depleted n-C25:1 and n-C27:1 alk-1-enes. These alkenes were not detected in soil and litter from near the shoreline and from the inner rim of the crater, pointing to an autochthonous, aquatic source. Analysis of suspended particulate matter indicated that the n-alk-1-enes are produced in the well-oxygenated upper 30m of the water column, indicating a phytoplanktonic origin. Sedimenting particles collected monthly from December 2006 to November 2007 showed increased fluxes of n-alk-1-enes following the locally prominent short rain season in November-December. Green algae and/or cyanobacteria were identified as candidate sources of these alkenes. Production of the n-C25:1 and n-C27:1 alkenes in Lake Challa was much reduced during the Last Glacial Maximum and early late-glacial period, suggesting a temperature or CO2 effect on habitat suitability. We explored the potential of n-alk-1-ene accumulation rates, and of a derived Alkene Index [n-C27:1]/([n-C25:1]+[n-C27:1]), to record longer-term climatic changes. The Alkene Index record of Lake Challa over the past 25kyr shows clear periodicity with a dominant frequency of ~2.3kyr, potentially indicative of monsoon variability directly or indirectly forced by variation in solar radiation. © 2014 Elsevier Ltd. 2014 English 00167037 10.1016/j.gca.2014.08.035 Geochimica et Cosmochimica Acta 145 Elsevier Ltd 89-102 NIOZ Royal Netherlands Institute for Sea Research, Department of Marine Organic Biogeochemistry, P.O. Box 59, AB Den Burg, 1790, Netherlands; Utrecht University, Faculty of Geosciences, Department of Earth Sciences, P.O. Box 80.021, TA Utrecht, 3508, Netherlands; National Botanic Garden of Belgium, Domein van Bouchout, Meise, B-1860, Belgium; Ghent University, Limnology Unit, K.L. Ledeganckstraat 35, Gent, B-9000, Belgium; Department of Botany and Microbiology, Addiriyah Chair for Environmental Studies, College of Science, King Saud University, P.O. Box 245511451 Riyadh, Saudi Arabia accumulation rate; alkene; climate variation; cyanobacterium; geological record; green alga; lacustrine deposit; Last Glacial Maximum; monsoon; paleoclimate; paleoenvironment; solar radiation; suspended particulate matter, Kilimanjaro [Kilimanjaro (RGA)]; Kilimanjaro [Tanzania]; Lake Challa; Tanzania https://www.scopus.com/inward/record.uri?eid=2-s2.0-84908192035&doi=10.1016%2fj.gca.2014.08.035&partnerID=40&md5=5d5efd353a206eaf2f9c8c7ce625f06f cited By 16 L.G.J. Van Bree W.I.C. Rijpstra C. Cocquyt N.A. Al-Dhabi D. Verschuren J.S. Sinninghe Damsté J.W. Leeuw article Vuillemin2014101 Article 2014 10.1007/s00027-013-0317-4 Aquatic Sciences 76 101 – 114 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84891648336&doi=10.1007%2fs00027-013-0317-4&partnerID=40&md5=0537648b112f488df732a8d85118f1d7 Cited by: 14 Aurèle Vuillemin Daniel Ariztegui Andreas Lücke Christoph Mayr article Vigliotti201418 In the framework of the PALEOVAN project, a high-resolution paleomagnetic and rock magnetic study was carried out on a 149m sedimentary sequence recovered from Ahlat Ridge in the deepest part of the Lake Van (Eastern Turkey; ICDP Site 5034-2). High sedimentation rates (average ~30cm/ka) allow high-resolution measurements of natural remanent magnetization (NRM), magnetic susceptibility (κ), anhysteretic remanence (ARM) and hence of anhysteretic susceptibility (κARM) over the last 350ka. The carrier of the remanence is detrital titanomagnetite largely from volcanic sources, based on the similarity of magnetite grain size of tephra layers and the other lacustrine lithologies observed in a plot of the κ versus κARM. Bulk magnetic parameters often covary with paleoclimatic signals in the Lake Van sediments. A correlation exists between variations of κ and ARM intensity and glacial-interglacial marine isotopic stages, as well as dust flux and temperatures observed in ice cores from Greenland and Antarctica. The quality of the paleomagnetic record is compromised by weak NRM intensities, as well as by the presence of tephra and turbidites throughout the sequence. Nonetheless, a correlation is observed between the relative paleointensity (RPI) record, based on NRM/ARM, and the calibrated PISO RPI stack, that supports the independently derived age model for the site. © 2014 Elsevier Ltd. 2014 English 02773791 10.1016/j.quascirev.2014.09.028 Quaternary Science Reviews 104 Elsevier Ltd 18-29 Istituto di Scienze Marine, ISMAR-CNR, Bologna, Italy; Department of Geological Sciences, University of Florida, Gainesville, FL 32611, United States; Eawag, Swiss Federal Institute of Aquatic Science and Technology, Dept. of Surface Waters Dübendorf, Switzerland; ETH Zurich, Geological Institute, Zurich, Switzerland Lacustrine sediments; Lake vans; Late quaternary; Paleoclimates; Paleomagnetism, grain size; lacustrine deposit; magnetic intensity; magnetic susceptibility; natural remanent magnetization; paleoclimate; paleoenvironment; paleomagnetism; Quaternary; sedimentary sequence; sedimentation rate; tephra, Lake Van; Turkey https://www.scopus.com/inward/record.uri?eid=2-s2.0-84909633301&doi=10.1016%2fj.quascirev.2014.09.028&partnerID=40&md5=3c7286d9bafe6cdef194b79434db494f cited By 25 L. Vigliotti J.E.T. Channell M. Stockhecke article cp-10-1109-2014 2014 10.5194/cp-10-1109-2014 Climate of the Past 10 1109-1123 3 https://cp.copernicus.org/articles/10/1109/2014/ G. Schwamborn H. Meyer L. Schirrmeister G. Fedorov article HAUKSSON201476 Material tests and scrubbing experiments were carried out at the IDDP-1 well in the Krafla geothermal field in Iceland. The 450°C superheated steam contained acid gas (approx. 90mg/kg HCl and 7mg/kg HF) and was highly corrosive when it condensed making it unsuitable for utilization without scrubbing. The acid gas could effectively be scrubbed from the steam with water. The steam contained gasous sulfur compond (80–100mg/kgS), which could only be scrubbed from the steam with alkaline water. The steam contained both silica dust and dissolved silica which was effectively washed from the steam with wet scrubbing. Experiments on corrosion and erosion resistance of metals and alloys were problematic to run because of equipment clogging by silica dust. 2014 0375-6505 https://doi.org/10.1016/j.geothermics.2013.07.003 Geothermics 49 76-82 Steam scrubbing, Acid, Sulfur, Silica dust https://www.sciencedirect.com/science/article/pii/S0375650513000515 Iceland Deep Drilling Project:The first well, IDDP-1, drilled into Magma Trausti Hauksson Sigurdur Markusson Kristján Einarsson Sigrun Nanna Karlsdóttir Ásbjörn Einarsson Aðalsteinn Möller Þorsteinn Sigmarsson article hanski2014new 2014 Precambrian Research 245 Elsevier 51--65 Eero J Hanski Hannu Huhma Victor A Melezhik article Jackson2014488 Surtsey, an isolated oceanic island and a World Heritage Site of the United Nations Educational, Scientific and Cultural Organization, is a uniquely well-documented natural laboratory for investigating processes of rift zone volcanism, hydrothermal alteration of basaltic tephra, and biological colonization and succession in surface and subsurface pyroclastic deposits. Deposits from Surtsey's eruptions from 1963 to 1967 were first explored via a 181-meter hole drilled in 1979 by the U.S. Geological Survey and Icelandic Museum of Natural History. © 2014. American Geophysical Union. All Rights Reserved. 2014 English 00963941 10.1002/2014EO510006 Eos (United States) 95 Blackwell Publishing Ltd 488 Department of Civil and Environmental Engineering, University of California, Berkeley, United States 51 colonization; conference proceeding; drilling; hydrothermal alteration; microbial activity; mineral; pyroclastic deposit; rift zone; tephra; volcanic eruption; volcanism; World Heritage Site, Iceland; Surtsey https://www.scopus.com/inward/record.uri?eid=2-s2.0-84919719342&doi=10.1002%2f2014EO510006&partnerID=40&md5=db55288812b346ff84403c093c4c6d6a cited By 2 M.D. Jackson article Qu2014786 Cretaceous non-marine deposits are widespread in China and have been studied comprehensively. The Songliao Basin in northeast China is thought to be well suited for investigation of Cretaceous biostratigraphy. However, despite much research having been conducted in the basin, little is known about its Late Cretaceous biostratigraphy and paleoenvironment. Here, we establish a high-resolution biostratigraphy of the Late Cretaceous based on ostracods from borehole SK1(n) in the Songliao Basin, northeast China. As part of the present study, 45 species assigned to 20 genera have been recovered, with one new species (Ilyocypris bisulcata n. sp.) and five ostracod assemblages: the Cypridea gunsulinensis-Mongolocypris magna assemblage, which is marked by the first occurrence (F.O.) of Ilyocyprimorpha with nodes and spines; the Ilyocyprimorpha-Limnocypridea sunliaonensis-Periacanthella assemblage, which ranges from the F.O. of Ilyocyprimorpha with nodes and spines to the F.O. of Strumosia sp.; the Strumosia inandita assemblage from the F.O. of Strumosia sp. to the lower occurrence (L.O.) of Strumosia inandita; the Talicypridea amoena-Metacypris kaitunensis-Ziziphocypris simakovi assemblage from the F.O. of Mongolocypris apiculata (Cea) and Talicypridea amoena to the F.O. of Ilyocypris sp.; and the Ilyocypris assemblage from the F.O. of Ilyocypris sp. to the L.O. of Ilyocypris bisulcata n. sp. Moreover, the zonal fossil Ilyocypris bisulcata n. sp. of Zone 5 is here described for the first time from the upper Mingshui Formation, and Paleocene charophyte genera including Neochara and Grovesicahra have been found to coexist with the Zone 5 fauna. The age of the Ilyocypris Assemblage is assigned to the latest Maastrichtian to the earliest Danian. Copyright © 2014, The Paleontological Society. 2014 English 00223360 10.1666/13-076 Journal of Paleontology 88 Paleontological Society 786-798 State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences (Beijing), Xueyuanlu 29, Haidian District, Beijing 100083, China; State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, 39 East Beijing Road, Nanjing, Jiangsu 210008, China; Impasse des Biroulayres, 33610 Cestas, France; University of Lisbon, Faculty of Sciences, Centre of Geology, Campo Grande, C6, 3, 1749-016 Lisboa, Portugal; Exploration and Development Research Institute of Daqing Oil Field Corporation Ltd., Daqing Heilongjiang 163712, China 4 biostratigraphy; community structure; Cretaceous; Danian; fossil record; Maastrichtian; new species; ostracod; Paleocene; paleoenvironment; taxonomy, China; Songliao Basin https://www.scopus.com/inward/record.uri?eid=2-s2.0-84904103740&doi=10.1666%2f13-076&partnerID=40&md5=6f8a7681d29e4ecbc15e1bf259846918 cited By 29 H. Qu D. Xi S. Li J.P. Colin Q. Huang X. Wan article Peng2014061 A new medium-sized species of Hippodonta (Bacillariophyceae) is described from Lake Qinghai, China. The morphology and ultrastructure of Hippodonta qinghainensis sp. nov. are described using light and scanning electron microscopy. This new species is compared with similar species of Hippodonta using conventional and geometric morphometric analyses. Hippodonta qinghainensis can be separated from the other species of Hippodonta by a unique combination of characters that include an elliptic-lanceolate to rhombic-lanceolate valve shape, non protracted apices, the absence of fascia, relatively coarse, uniseriate striae and the presence of two rows of lineolae around the valves apices. © 2014 Magnolia Press. Article 2014 English 11793155 10.11646/phytotaxa.186.2.1 Phytotaxa 186 Magnolia Press 061 – 074 2 Bacillariophyceae; Bacillariophyta; Hippodonta https://www.scopus.com/inward/record.uri?eid=2-s2.0-84911460773&doi=10.11646%2fphytotaxa.186.2.1&partnerID=40&md5=210e013ef399cde944904833600071d1 Cited by: 13 Yumei Peng Patrick Rioual Zlatko Levkov David M Wiliams Zhangdong Jin article Neugebauer2014149 The sedimentary sections that were deposited from the Holocene Dead Sea and its Pleistocene precursors are excellent archives of the climatic, environmental and seismic history of the Levant region. Yet, most of the previous work has been carried out on sequences of lacustrine sediments exposed at the margins of the present-day Dead Sea, which were deposited only when the lake surface level rose above these terraces (e.g. during the Last Glacial period) and typically are discontinuous due to major lake level variations in the past. Continuous sedimentation can only be expected in the deepest part of the basin and, therefore, a deep drilling has been accomplished in the northern basin of the Dead Sea during winter of 2010-2011 within the Dead Sea Deep Drilling Project (DSDDP) in the framework of the ICDP program. Approximately 720m ofsediment cores have been retrieved from two deep and several short boreholes. The longest profile (5017-1), revealed at a water depth of ~300m, reaches 455m below the lake floor (blf, i.e. to ~1175m below global mean sea level) and comprises approximately the last 220-240ka. The record covers the upper part of the Amora (penultimate glacial), the Last Interglacial Samra,the Last Glacial Lisan and the Holocene Ze'elim Formations and, therewith, two entire glacial-interglacial cycles. Thereby, for the first time, consecutive sediments deposited during the MIS 6/5, 5/4 and 2/1 transitions were recovered from the Dead Sea basin, which are not represented in sediments outcropping on the present-day lake shores. In this paper, we present essential lithological data including continuous magnetic susceptibility and geochemical scanning data and the basic stratigraphy including first chronological data of the long profile (5017-1) from the deep basin. The results presented here (a) focus on the correlation of the deep basin deposits with main on-shore stratigraphic units, thus providing a unique comprehensive stratigraphic framework for regional paleoenvironmental reconstruction, and (b) highlight the outstanding potential of the Dead Sea deep sedimentary archive to record hydrological changes during interglacial, glacial and transitional intervals. © 2014 Elsevier Ltd. 2014 English 02773791 10.1016/j.quascirev.2014.08.013 Quaternary Science Reviews 102 Elsevier Ltd 149-165 Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences, Section 5.2 - Climate Dynamics and Landscape Evolution, Telegrafenberg, Potsdam, D-14473, Germany; Department of Marine Geosciences, Leon H. Charney School of Marine Sciences, University of Haifa, Mount Carmel, 31905, Israel; Department of Earth Science, University of Bergen, Allégaten 41, Bergen, 5007, Norway; The Fredy and Nadine Herrmann Institute of Earth Sciences, The Hebrew University of Jerusalem, Givat Ram, Jerusalem, 91904, Israel; Graduate School of Environmental Studies, Nagoya University, Chikusa-ku, Nagoya, 464-8601, Japan; The Interuniversity Institute for Marine Sciences of Eilat, Eilat, 88103, Israel; Department of Earth Sciences, University of Geneva, Rue des Maraichers 13, Geneva, CH-1205, Switzerland; Department of Geophysical, Atmospheric and Planetary Sciences, Tel Aviv University, Tel Aviv, 69978, Israel; Leon H. Charney School of Marine Sciences, University of Haifa, Mount Carmel, 31905, Israel; Lamont-Doherty Earth Observatory and Department of Earth and Environmental Sciences, Columbia University, 61 Route 9W, Palisades, NY 10964, United States; Geological Survey of Israel, 30 Malkhe Israel St., Jerusalem, 95501, Israel Glacial geology; Infill drilling; Lakes; Lithology; Magnetic susceptibility; Salinity measurement; Sea level; Sedimentology; Stratigraphy, Deep drilling; Hypersaline lakes; Laminated sediments; Paleoclimates; Sediment facies, Sediments, deep drilling; depositional sequence; facies; Holocene; hypersaline environment; lithology; magnetic susceptibility; ocean basin; outcrop; paleoclimate; paleoenvironment; sediment core; sedimentation; sequence stratigraphy; water depth, Dead Sea https://www.scopus.com/inward/record.uri?eid=2-s2.0-84908166752&doi=10.1016%2fj.quascirev.2014.08.013&partnerID=40&md5=a64030e7bcbe347ee93f60a163f97504 cited By 86 I. Neugebauer A. Brauer M.J. Schwab N.D. Waldmann Y. Enzel H. Kitagawa A. Torfstein U. Frank P. Dulski A. Agnon D. Ariztegui Z. Ben-Avraham S.L. Goldstein M. Stein DSDDP Scientific Party article Lepland201420 All known forms of life require phosphorus, and biological processes strongly influence the global phosphorus cycle. Although the record of life on Earth extends back to 3.8 billion years ago and the advent of biological phosphate processing can be tracked to at least 3.5 billion years ago, the earliest known P-rich deposits appeared only 2 billion years ago. The onset of P deposition has been attributed to the rise of atmospheric oxygen 2.4-2.3 billion years ago and the related profound biogeochemical shifts, which increased the riverine input of phosphate to the ocean and boosted biological productivity and phosphogenesis. However, the P-rich deposits post-date the rise of oxygen by about 300 million years. Here we use microfabric, trace element and carbon isotope analyses to assess the environmental setting and redox conditions of the 2-billion-year-old P-rich deposits of the vent-or seep-influenced Zaonega Formation, northwest Russia. We identify phosphatized microorganism fossils that resemble modern methanotrophic archaea and sulphur-oxidizing bacteria, analogous to organisms found in modern seep settings and upwelling zones with a sharp redoxcline. We therefore propose that the P-rich deposits in the Zaonega Formation were formed by phosphogenesis mediated by sulphur bacteria, similar to modern sites, and by the precipitation of calcium phosphate minerals on microbial templates during early diagenesis. © 2014 Macmillan Publishers Limited. 2014 English 17520894 10.1038/ngeo2005 Nature Geoscience 7 20-24 Geological Survey of Norway, 7491 Trondheim, Norway; Tallinn University of Technology, Institute of Geology, 19086 Tallinn, Estonia, Estonia; Centre for Arctic Gas Hydrate, Environment and Climate, University of Tromsø, 9037 Tromsø, Norway; University of Tartu, Department of Geology, 50411 Tartu, Estonia; Department of Earth and Environmental Sciences, University of St Andrews, St-Andrews-KY16-9AL, United Kingdom; Institute of Geology, Karelian Science Centre, Pushkinskaya 11, 185610 Petrozavodsk, Russian Federation; Ivan Rakovec Institute of Paleontology, ZRC, SAZU, SI-1000 Ljubljana, Slovenia; NERC Isotope Geosciences Laboratory, British Geological Survey, Keyworth, Nottingham NG12 5GG, United Kingdom; Scottish Universities, Environmental Research Centre, Scottish Enterprise Technology Park, Rankine Avenue, East Kilbride, G75 0QF, United Kingdom; Géobiosphère Actuelle et Primitive, Institut de Physique du Globe de Paris, Université Paris Diderot, 1 rue Jussieu, 75238 Paris cedex 5, France; GeoForschungsZentrum Potsdam, Telegrafenberg, Chemistry and Physics of Earth Materials, D-14473 Potsdam, Germany; GNS Science, Private Bag 1930, 9054 Dunedin, New Zealand 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84893853853&doi=10.1038%2fngeo2005&partnerID=40&md5=87a1aa53dcd7d3f8c7840e4250e27adc cited By 44 A. Lepland L. Joosu K. Kirsimäe A.R. Prave A.E. Romashkin A.E. Črne A.E. Fallick P. Somelar K. Üpraus K. Mänd N.M.W. Roberts M.A. Van Zuilen A. Schreiber article Litt20141 A complete succession of the lacustrine sediment sequence deposited during the last ~600,000 years in Lake Van, Eastern Anatolia (Turkey) was drilled in 2010 supported by the International Continental Scientific Drilling Program (ICDP). Based on a detailed seismic site survey, two sites at a water depth of up to 360m were drilled in summer 2010, and cores were retrieved from sub-lake-floor depths of 140m (Northern Basin) and 220m (Ahlat Ridge). To obtain a complete sedimentary section, the two sites were multiple cored in order to investigate the paleoclimate history of a sensitive semi-arid region between the Black, Caspian, and Mediterranean seas. This introductory paper provides background information of the deep drilling project and an overview of the studies presented in this special volume by the PALEOVAN science team dealing with chronology, paleomagnetism, paleoenvironmental proxies, geophysical and petrophysical investigations as well as pore-water and fluid transport. © 2014 Elsevier Ltd. 2014 English 02773791 10.1016/j.quascirev.2014.09.026 Quaternary Science Reviews 104 Elsevier Ltd 1-7 University of Bonn, Steinmann Institute of Geology, Mineralogy and Paleontology, Nussallee 8, Bonn, 53115, Germany; Institute of Geological Sciences and Oeschger Centre for Climate Change Research, University of Bern, Baltzerstrasse 1-3, Bern, 3012, Switzerland Deep drilling; Lake vans; Long continental record; Near East; Quaternary, deep drilling; lacustrine deposit; paleoclimate; Quaternary; sediment core; seismic survey; semiarid region, Lake Van; Turkey https://www.scopus.com/inward/record.uri?eid=2-s2.0-84909643137&doi=10.1016%2fj.quascirev.2014.09.026&partnerID=40&md5=926d58105fc64bb301f18c9b94357564 cited By 33 T. Litt F.S. Anselmetti article Zhao20142985 Cretaceous climate was warmer than today. The Songliao Basin contains one of the most important Late Cretaceous non-marine deposits in China for the research of the paleoenvironment and paleoclimate. This research is based on core samples from the SK1(S) borehole. The strata sampled are the upper part of the Quantou Formation to member 2 of the Nenjiang Formation, where spores, pollen, dinoflagellates, and other microfossils are abundantly preserved. Based on analysis of the spores and pollen fossils from the core samples, the following six fossil assemblage zones have been recognized in ascending order: The Cicatricosisporites-Cyathidites-Pinuspollenites, Schizaeoisporites-Cyathidites-Classopollis, Cyathidites-Schizaeoisporites, Schizaeoisporites-Cyathidites-Proteacidites, Proteacidites-Cyathidites-Dictyotriletes, and the Lythraites-Callistipollenites-Schizaeoisporites zones. The six fossil zones range from the late Cenomanian to early Campanian. The Late Cretaceous dinoflagellate cysts in the Songliao Basin are of high abundance and low diversity. Specific phytoplankton types reflect salinity changes of the Songliao Lake. Paleoecology of the dinoflagellates suggests that sediments of members 2 and 3 of the Yaojia Formation (K2y2+3) were deposited in a freshwater environment, whereas members 2 and 3 of the Qingshankou Formation (K2q2+3) and members 1 and 2 of the Nenjiang Formation (K2n1+2) were deposited in freshwater to brackish water environments. Combined with the paleoecology of dinoflagellates and the palynomorph biozones, valuable information of the paleoclimate was provided. The quantitative analyses of spores and pollen fossils, such as vegetation type, climate type, and humidity type, diversity and dominance, indicate a relatively sub-humid, mid-subtropical paleoclimate, with slight climatic fluctuation and/or temporal change. © 2014, Science China Press and Springer-Verlag Berlin Heidelberg. 2014 English 16747313 10.1007/s11430-014-4975-4 Science China Earth Sciences 57 Science Press (China) 2985-2997 State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing, 100083, China; Exploration and Development Research Institute of Huabei Oil Field Corporation Ltd., Renqiu, 062552, China; Guangzhou Marine Geological Survey, Guangzhou, 510075, China; Exploration and Development Research Institute of Daqing Oil Field Corporation Ltd., Daqing, 163712, China 12 Climate change; Ecology; Water, dinoflagellate; Late cretaceous; Paleoclimates; Songliao basin; spores and pollen, Core samples, borehole; climate variation; Cretaceous; dinoflagellate cyst; dominance; fossil assemblage; microfossil; paleoclimate; paleoecology; paleoenvironment; palynology; sediment core; species diversity; warming, China; Songliao Basin, Dinophyceae https://www.scopus.com/inward/record.uri?eid=2-s2.0-84916236887&doi=10.1007%2fs11430-014-4975-4&partnerID=40&md5=f94415601c614c4078e3222db1f3817b cited By 32 J. Zhao X.Q. Wan D.P. Xi X. Jing W. Li Q.H. Huang J.Y. Zhang article Kotthoff20141523 We investigated the palynology of sediment cores from Site M0027 of IODP (Integrated Ocean Drilling Program) Expedition 313 on the New Jersey shallow shelf to examine vegetation and climate dynamics on the east coast of North America between 33 and 13 million years ago and to assess the impact of over-regional climate events on the region. Palynological results are complemented with pollen-based quantitative climate reconstructions. Our results indicate that the hinterland vegetation of the New Jersey shelf was characterized by oak-hickory forests in the lowlands and conifer-dominated vegetation in the highlands from the early Oligocene to the middle Miocene. The Oligocene witnessed several expansions of conifer forest, probably related to cooling events. The pollen-based climate data imply an increase in annual temperatures from ∼11.5 °C to more than 16 °C during the Oligocene. The Mi-1 cooling event at the onset of the Miocene is reflected by an expansion of conifers and mean annual temperature decrease of ∼4 °C, from ∼16 °C to ∼12 °C around 23 million years before present. Relatively low annual temperatures are also recorded for several samples during an interval around ∼20 million years before present, which may reflect the Mi-1a and the Mi-1aa cooling events. Generally, the Miocene ecosystem and climate conditions were very similar to those of the Oligocene. Miocene grasslands, as known from other areas in the USA during that time period, are not evident for the hinterland of the New Jersey shelf, possibly reflecting moisture from the proto-Gulf Stream. The palaeovegetation data reveal stable conditions during the mid-Miocene climatic optimum at ∼15 million years before present, with only a minor increase in deciduous-evergreen mixed forest taxa and a decrease in swamp forest taxa. Pollen-based annual temperature reconstructions show average annual temperatures of ∼14 °C during the mid-Miocene climatic optimum, ∼2 °C higher than today, but ∼1.5 °C lower than preceding and following phases of the Miocene. We conclude that vegetation and regional climate in the hinterland of the New Jersey shelf did not react as sensitively to Oligocene and Miocene climate changes as other regions in North America or Europe due to the moderating effects of the North Atlantic. An additional explanation for the relatively low regional temperatures reconstructed for the mid-Miocene climatic optimum could be an uplift of the Appalachian Mountains during the Miocene, which would also have influenced the catchment area of our pollen record. © Author(s) 2014. 2014 English 18149324 10.5194/cp-10-1523-2014 Climate of the Past 10 1523-1539 Institut für Geologie, Centrum für Erdsystemforschung und Nachhaltigkeit, Universität Hamburg, Bundesstraße 55, 20146 Hamburg, Germany; Department of Biology, Brandon University, 270 18th Street, Brandon, MN, R7A 6A9, Canada; Department of Earth Sciences, Brock University, 500 Glenridge Avenue, St. Catharines, ON, L2S 3A1, Canada; Camborne School of Mines, College of Engineering, Mathematics and Physical Sciences, University of Exeter, Treliever Road, Penryn, Cornwall TR10 9FE, United Kingdom 4 climate variation; Eocene; Miocene; paleoclimate; palynology; reconstruction; regional climate; sediment core, Atlantic Coastal Plain; New Jersey; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-84936933799&doi=10.5194%2fcp-10-1523-2014&partnerID=40&md5=75a88e0e41af19d6009695be3182d56e cited By 29 U. Kotthoff D.R. Greenwood F.M.G. McCarthy K. Müller-Navarra S. Prader S.P. Hesselbo article Cvetkoska201422 Lake Prespa (Macedonia/Albania/Greece) occupies an important location between Mediterranean and central European climate zones. Although previous multi-proxy research on the Late Glacial to Holocene sequence, core Co1215 (320cm; ca. 17cal ka BP to present), has demonstrated its great value as an archive of Quaternary palaeoclimate data, some uncertainty remains in the interpretation of climate change. With the exception of oxygen stable isotope data, previous palaeolimnological interpretation has relied largely on proxies for productivity. Here, existing interpretation is strengthened by the addition of diatom data. Results demonstrate that shifts in diatom assemblage composition are driven primarily by lake-level changes and thus permit more confident interpretation of shifts in moisture availability over time, while corroborating previous interpretation of catchment- and climate-induced productivity shifts. An inferred cold, arid shallow lake phase between ca. 17.1 and 15.7cal ka BP is not only followed by a high-productivity phase from ca. 15.7cal ka BP with Late Glacial warming, but also is the first evidence for a gradual increase in lake level, in line with other regional records. Clear evidence for a Younger Dryas climate reversal between ca. 13.1 and 12.3cal ka BP is followed by an unusually gradual transition to the Holocene and deeper, oligotrophic-mesotrophic lake conditions are reached by ca. 11.0cal ka BP. In contrast to the arid episode from ca. 10.0 to 8.0ka inferred from positive 18δOcalcite values, rapid diatom-inferred lake-level increase after the start of the Holocene suggests high moisture availability, in line with palynological evidence, but with only very subtle evidence for the impact of an 8.2ka cold event. The maintenance of high lake levels until 1.9cal ka BP, and the peak of inferred humidity from ca. 7.9 to 6.0cal ka BP, matches the oxygen stable isotope profile and confirms that the latter is driven primarily by evaporative concentration rather than reflecting regional shifts in precipitation sources over time. During the Late Holocene progressive eutrophication is inferred between 1.9 and present. Two shallow phases at ca. 1.0cal ka BP and at ca. 100years ago probably represent an aridity response which is added to increase human impact in the catchment. Overall, the study is important in confirming previous tentative inferences that Late Glacial to Holocene moisture availability has strong affinity with other sites in the Eastern Mediterranean. It also tracks the pattern of North Atlantic forcing. © 2014 Elsevier B.V. Article 2014 English 00310182 10.1016/j.palaeo.2014.04.010 Palaeogeography, Palaeoclimatology, Palaeoecology 406 Elsevier 22 – 32 Albania; Greece; Lake Mikri Prespa; Macedonia [Greece]; anthropogenic effect; aridity; climate variation; community composition; diatom; Holocene; lake level; late glacial; Mediterranean environment; moisture content; paleoclimate; paleoecology; paleolimnology; paleoproductivity; palynology; Younger Dryas https://www.scopus.com/inward/record.uri?eid=2-s2.0-84900544601&doi=10.1016%2fj.palaeo.2014.04.010&partnerID=40&md5=2cd49d2fa17f5ea08869fcedfdbdbd2c Cited by: 25; All Open Access, Green Open Access Aleksandra Cvetkoska Zlatko Levkov Jane M. Reed Bernd Wagner article cp-10-1017-2014 The 318m thick lacustrine sediment record from Lake El'gygytgyn, northeastern Russian Arctic cored by the international El'gygytgyn Drilling Project provides unique opportunities for the time-continuous reconstruction of the regional paleoenvironmental history for the past 3.6 Myr. Pollen studies of the lower 216m of the lacustrine sediments demonstrate their value as an excellent archive of vegetation and climate changes during the Late Pliocene and Early Pleistocene. About 3.5-3.35 Myr BP, the vegetation at Lake El'gygytgyn, now an area of tundra was dominated by spruce-larch-fir-hemlock forests. After ca. 3.35 Myr BP dark coniferous taxa gradually disappeared. A very pronounced environmental change took place ca. 3.31-3.28 Myr BP, corresponding to the Marine Isotope Stage (MIS) M2, when treeless tundra- and steppe-like habitats became dominant in the regional vegetation. Climate conditions were similar to those of Late Pleistocene cold intervals. Numerous coprophilous fungi spores identified in the pollen samples suggest the presence of grazing animals around the lake. Following the MIS M2 event, larch-pine forests with some spruce mostly dominated the area until ca. 2.6 Myr BP, interrupted by colder and drier intervals ca. 3.043-3.025, 2.935-2.912, and 2.719-2.698 Myr BP. At the beginning of the Pleistocene, ca. 2.6 Myr BP, noticeable climatic deterioration occurred. Forested habitats changed to predominantly treeless and shrubby environments, which reflect a relatively cold and dry climate. Peaks in observed green algae colonies (Botryococcus) around 2.53, 2.45, 2.32-2.305, 2.20 and 2.16-2.15 Myr BP suggest a spread of shallow water environments. A few intervals (i.e., 2.55-2.53, ca. 2.37, and 2.35-2.32 Myr BP) with a higher presence of coniferous taxa (mostly pine and larch) document some relatively shortterm climate ameliorations during Early Pleistocene glacial periods. © Author(s) 2014. 2014 English 18149324 10.5194/cp-10-1017-2014 Climate of the Past 10 European Geosciences Union 1017-1039 Institute of Geology and Mineralogy, University of Cologne, Zülpicherstr. 49a, 50674 Cologne, Germany; Free University Berlin, Institute of Geological Sciences, Paleontology Section, Malteserstr. 74-100, Haus D, 12249 Berlin, Germany; Arctic and Antarctic Research Institute, Bering St. 38, 199397 St. Petersburg, Russian Federation; Alfred Wegener Institute for Polar and Marine Research, Telegrafenberg A43, 14473 Potsdam, Germany; Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences, Section 5.2 - Climate Dynamics and Landscape Evolution, Telegrafenberg, 14473 Potsdam, Germany; Department of Geosciences, University of Massachusetts, 611 North Pleasant Str., Amherst, MA 01003, United States 3 climate variation; coniferous forest; glacial history; green alga; lacustrine deposit; marine isotope stage; paleoenvironment; palynology; Pleistocene; Pliocene; reconstruction; sediment analysis; spore; vegetation history, Arctic; Chukchi; Elgygytgyn Lake; Russian Federation https://cp.copernicus.org/articles/10/1017/2014/ cited By 36 A. A. Andreev P. E. Tarasov V. Wennrich E. Raschke U. Herzschuh N. R. Nowaczyk J. Brigham-Grette M. Melles article Lazar201494 The geological evolution of the unique Dead Sea Ca-chloride brine has been the focus of many research efforts for several decades. These studies relied on the information obtained from sedimentary exposures of the marginal terraces of the modern Dead Sea, mostly documenting the history of the surface lake brine during its high stands periods. The present study is the first attempt to establish the history of the deepest part of the lake by direct measurements of the chemical and isotopic composition of pore-fluids that were extracted from cores drilled during 2011 by ICDP in the deep basin of the Dead Sea at water depth of 300 m. The vertical profiles of chloride (Cl-) and oxygen isotopes (δO18) in pore brines reveal a substantial decrease in the salinity of the hyper-saline lake during the last glacial and particularly during MIS2 (~31-17 kaBP). The Cl- concentration of the deep brine in the lake decreased gradually, reaching a minimum of less than 2/3 of its present value while the δO18 increased to maximum of ~7‰ (3‰ higher than today). The low Cl- indicates significant dilution of the bottom water mass (hypolimnion) of Lake Lisan (the last glacial predecessor of the modern Dead Sea) during its highest stand period. Beforehand, during the interglacial and later during the post-glacial and the Holocene the Cl- concentrations and δO18 values were similar to those of the modern Dead Sea. The slow dilution of the deep Ca-chloride brine was caused probably by continuous turbulent mixing of the hypolimnion with the less saline high δO18 epilimnetic brine, across the epilimnion/hypolimnion interface (EHI). While the increase in δO18 during the salinity decrease of Lake Lisan is a result of "normal" evaporation of the less saline epilimnetic brine, the post-glacial δO18 decrease (contemporaneous with salinity increase) is attributed to the "reversed" behavior of δO18 during evaporation of high salinity brine. During the long freshening period the hypolimnion was enriched with dissolved sulfate supplied by the freshwater and transported by the turbulent mixing across the EHI until reaching gypsum saturation that commenced massive gypsum deposition at the end of this period, when full overturn took place. © 2014 Elsevier B.V. 2014 English 0012821X 10.1016/j.epsl.2014.03.019 Earth and Planetary Science Letters 400 Elsevier 94-101 Fredy and Nadine Herrmann Institute of Earth Sciences, The Hebrew University, Edmond J. Safra Campus, Givat Ram, Jerusalem 91904, Israel; Department of Geological and Environmental Sciences, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel; Geological Survey of Israel, 30 Malkhe Israel St., Jerusalem 95501, Israel; Department of Earth Sciences, University of Cambridge, Cambridge CB2 3EQ, United Kingdom Calcium; Chlorine; Chlorine compounds; Evaporation; Glacial geology; Gypsum; Isotopes; Lakes; Mixing; Oxygen; Paleolimnology; Shock tubes; Turbulent flow, Chloride; Dead sea; Oxygen isotopes; Pore brine profiles; Quarter-nary, Brines, brine; Chinese Continental Scientific Drilling Project; chloride; isotopic composition; oxygen isotope; paleolimnology; Quaternary, Dead Sea https://www.scopus.com/inward/record.uri?eid=2-s2.0-84901838098&doi=10.1016%2fj.epsl.2014.03.019&partnerID=40&md5=26585071502ac4171b5cc6f9a7e6f6bd cited By 24 B. Lazar O. Sivan Y. Yechieli E.J. Levy G. Antler I. Gavrieli M. Stein article Wagner201425 Continental scientific drilling is an important tool for exploring natural and anthropogenic processes on Earth. In past decades the results obtained from lake drilling projects contributed significantly to a better understanding of short-term and long-term climate change and natural hazards. ©2014. American Geophysical Union. All Rights Reserved. Short survey 2014 English 00963941 10.1002/2014EO030001 Eos 95 American Geophysical Union 25 – 26 3 Lake Ohrid; climate variation; core analysis; deep drilling; lacustrine deposit; natural hazard; paleoclimate; paleolimnology; paleontology; stratigraphic correlation; Earth https://www.scopus.com/inward/record.uri?eid=2-s2.0-84899094924&doi=10.1002%2f2014EO030001&partnerID=40&md5=eb091c15780d483c878e405e0e4b892c Cited by: 16; All Open Access, Bronze Open Access Bernd Wagner Thomas Wilke Sebastian Krastel Giovanni Zanchetta Roberto Sulpizio Klaus Reicherter Melanie Leng Andon Grazhdani Sasho Trajanovski Zlatko Levkov Jane Reed Thomas Wonik article Kontny2014224 The Outokumpu (OKU) assemblage was studied in drill cores from the 2516m deep OKU Deep Drill Hole, Finland, and we observed that the strongest magnetic anomalies found in borehole measurements are related to three ferrimagnetic metaperidotite units with magnetic susceptibilities of up to 93×10-3SI separated by paramagnetic rock units. The main ferrimagnetic minerals are magnetite and minor pyrrhotite. Magnetic fabric studies were done in order to examine deformation within the OKU assemblage during the collisional deformation event 1.9Ga ago. Well-defined magnetic axes (kmax, kmin) and nearly horizontal magnetic foliation subparallel to the macroscopic foliation occur at the top and the bottom of the OKU formation. Low- and high-field AMS measurements showed that ferri- and paramagnetic subfabrics are coaxial. Paramagnetic units intercalated between the ferrimagnetic units show mostly triaxial magnetic fabrics, and low degrees of magnetic anisotropy values (P'<1.3) with a high variation of the shape factor (T) from prolate to oblate shapes. P' of the ferrimagnetic metaperidotite is high and range between 1.3 and 3.6 and T tends to more oblate shapes (T>0). Ferrimagnetic unit 2 shows the highest magnetic susceptibility and P' up to 5.6, which is related to a high amount of magnetite and pyrrhotite mostly concentrated in huge aggregates and veins. Alignment of magnetic minerals parallel with the structural foliation and the high P' values in the ferrimagnetic metaperidotite indicate that magnetic fabric was acquired in a high strain zone. The magnetic fabrics represent shear zone (SC) fabrics, which have been formed during early obduction-related deformation of the Svecofennian orogeny. The stacked sequence of the ferri- and paramagnetic metaperidotite bodies can be interpreted as a thrust system with an imbricate fan, in which three individual listric thrust sheets occur. This interpretation is in accordance with previous tectonic models of the Outokumpu area. © 2014 Elsevier B.V. Article 2014 English 00401951 10.1016/j.tecto.2014.04.011 Tectonophysics 629 Elsevier B.V. 224 – 237 Finland; Outokumpu; Pohjois-Karjala; Deformation; Drills; Ferrimagnetism; Horizontal wells; Infill drilling; Iron ores; Magnetic anisotropy; Magnetic susceptibility; Magnetite; Paramagnetism; Core drilling; Magnetism; Tectonics; Borehole measurements; Deep drilling; Ferrimagnetic minerals; Finland; Magnetic anomalies; Magnetic fabrics; Magnetic foliation; Outokumpu area; High-strain zones; Magnetic minerals; crustal structure; deformation; magnetic anisotropy; magnetic anomaly; magnetic fabric; magnetic mineral; magnetic susceptibility; peridotite; shear zone; deep drilling; geomagnetism; petrofabric; tectonic setting; Core drilling; Magnetic anisotropy https://www.scopus.com/inward/record.uri?eid=2-s2.0-84922777844&doi=10.1016%2fj.tecto.2014.04.011&partnerID=40&md5=c14374c7656a43dbd44d9aa3aee19aec Cited by: 2 Agnes Kontny Frank Dietze article Urrutia-Fucugauchi2014100 Magnetic susceptibility logging is used to study the impact breccias in the Chicxulub crater. The basic premise is that the high contrasts in magnetic properties can be used to characterize the breccias. The Santa Elena borehole was drilled 110 km radial distance from crater center and sampled a 172 m thick sequence of impact breccias, between 332 and 504 m depth. Breccia units are distinguished from differences in composition, size, and relative contents of clasts, type of matrix and textural and lithological assemblages, which can be resolved in the susceptibility logs. The whole-core log shows characteristic variation patterns with high, intermediate and low susceptibilities. High resolution logging of matrix and clasts records the heterogeneous nature of impactites, with higher variability at smaller spatial scales. Measurements confirm that diamagnetic susceptibilities characterize the carbonate clasts, high susceptibilities the basement granitic clasts and intermediate values the silicate melt-rich and silicate-poor matrix. Intermediate variable susceptibilities characterize breccias rich in melt particles. Correlation of matrix and clast logs with whole-core log shows that signal is controlled by the matrix. Logs for clast shows a discrete distribution with peaks of intermediate to high values, which correlate with large clast distributions. The ejecta blanket includes the fallback suevites rich in silicate melt particles and shocked minerals, the high temperature vapor deposits from ejecta curtain collapse and high velocity basal flows, and the carbonate rich deposits from lateral basal flows and secondary cratering. Late fallback suevites record minor turbulent conditions resulting from progressive cooling of the ejecta plume. © 2013 Institute of Geophysics of the ASCR, v.v.i. 2014 10.1007/s11200-013-0803-0 Studia Geophysica et Geodaetica 58 100-120 Programa Universitario de Perforaciones en Océanos y Continentes, Instituto de Geofisica, Universidad Nacional Autónoma de México, Ciudad Universitaria, Coyoacan, 04510 D.F, Mexico 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84893714213&doi=10.1007%2fs11200-013-0803-0&partnerID=40&md5=ab8793c484c4f4842a526175de98d4ec cited By 6 J. Urrutia-Fucugauchi L. Pérez-Cruz S.E. Campos-Arriola E. Escobar-Sánchez M. Velasco-Villarreal article cp-10-623-2014 Paleomagnetic measurements were performed on sediments drilled from ICDP Site 5011-1 in Lake El'gygytgyn (67°30' N, 172°05' E) located in Far East Russian Arctic. The lake partly fills a crater formed by a meteorite impact 3.58 ± 0.04 Ma ago. Sediments from three parallel cores (5011-1A, 5011-1B and 5011-1C), recovered from the middle part of the lake, yield a total of 355 m of sediment. Sediments are characterized by a variable lithology, where intervals of homogenous and laminated sediments alternate, and mass movement deposits occur frequently along the sediment profile. Mineral magnetic investigation made on sediments enclosed in core catchers suggests that magnetic carrier in these sediments is partly maghemitized Ti-rich pseudo-single domain magnetite. Its detrital origin can be shown by mineral magnetic measurements and SEM-EDS analyses performed on mini-sized cylindrical rock samples, polished rock sections and creek sediments. The intensity of the natural remanent magnetization in the sediments is high with a range from about 1 to 1000 mA mg-1. Most of the sediments carry a stable magnetization interpreted as primary depositional remanent magnetization. Characteristic inclination data show alternating intervals of steep positive and negative inclinations that are used to assign magnetic polarity to the lake sediment profile. This is a rather straightforward procedure owing to the mainly high quality of data. The Matuyama/Gauss (M/G) (2.608 Ma) and Brunhes/Matuyama (B/M) (0.780 Ma) reversals were recognized in the sediments. The Mammoth and Kaena reversed subchrons were identified during the Gauss chron, and the Olduvai and Jaramillo normal subchrons as well as the Réunion and Cobb Mountain cryptochrons were identified during the Matuyama chron. Sediments also provide a record of the Olduvai precursor and Intra-Jaramillo geomagnetic excursions. Sediment deposition rate is highest at the base of the sequence laid down in the early Gauss chron, when the deposition rate is approximately 44 cm kyr-1. Sediment deposition decelerates upcore and it is an order of magnitude lower during the Brunhes chron in comparison with the early Gauss chron. Decrease in sediment deposition in the late Pliocene probably relates to atmospheric and oceanic reorganization heralding the onset of Quaternary climate change. The high-quality magnetostratigraphy reconstructed from Lake El'gygytgyn sediments provides 12 first-order tie points to pin down the age of the longest paleoclimate record from the continental Arctic. © 2014 Author (s). 2014 English 18149324 10.5194/cp-10-623-2014 Climate of the Past 10 European Geosciences Union 623-642 Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences, Section 5.2 Climate Dynamics and Landscape Evolution, Telegrafenberg, 14473 Potsdam, Germany; University of Turku, Department of Geography and Geology, Section of Geology, 20014 Turku, Finland 2 climate variation; crater; deposition; lacustrine deposit; lamination; magnetite; magnetostratigraphy; mass movement; paleoclimate; paleomagnetism; Pliocene; proxy climate record; remanent magnetization; scanning electron microscopy; sediment core, Arctic; Chukchi; Elgygytgyn Lake; Russian Far East; Russian Federation https://cp.copernicus.org/articles/10/623/2014/ cited By 16 E. M. Haltia N. R. Nowaczyk article Lindhorst2014497 We study potential tsunami hazards associated with submarine landslides in Lake Ohrid, Macedonia/Albania. The transboundary Lake Ohrid located on the Balkan Peninsula shared by Macedonia and Albania is considered to be the oldestcontinuously existing lake in Europe (2–5 Ma), though the age and the origin are not completely unraveled to date. Previous studies by means of hydroacoustic methods have shown that the western margin of Lake Ohrid has a long history of mass wasting. Based on seismic data, slide deposits are found in different stratigraphic levels as well as on the lake floor where they have affected a large area. This study is focused on the well-studied Udenisht Slide Complex covering an area of 27 km2 within the southwestern part of Lake Ohrid. The Udenisht slide is by far the largest mass movement with an average thickness of 30–40 m and an estimated volume of about 0.11 km3. It is therefore well within the limits of submarine landslides that are known to be capable of triggering tsunamis. Using numerical modeling, the propagation of a landslide-generated tsunami with an initial wave height of more than 5 m has been calculated. Run-up heights estimated for coastal communities around the lake are moderate in the north (2–3 m) can reach up to 10 m directly at the site where the slide initiated. This study is a first generation of landslide tsunami hazard assessment for Lake Ohrid and further detailed modeling is recommended for the region. © Springer International Publishing Switzerland 2014. Book chapter 2014 English 18789897 10.1007/978-3-319-00972-8_44 Advances in Natural and Technological Hazards Research 37 Springer Netherlands 497 – 506 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85019624298&doi=10.1007%2f978-3-319-00972-8_44&partnerID=40&md5=19ad1eb81ee0c11e36a214b8ddb69089 Cited by: 5 Katja Lindhorst Sebastian Krastel Cord Papenberg Mohammed Heidarzadeh article AXELSSON201449 The transient temperature conditions near the bottom of well IDDP-1 in Krafla, which was drilled into a magma intrusion, have been simulated by some simple models of: (i) evolution of temperature conditions at the magma intrusion, (ii) cooling of the producing zone, a permeable layer above the intrusion, due to circulation losses during drilling and subsequent injection, (iii) reheating of the permeable layer after drilling and (iv) temperature evolution during the early phases of discharge testing in 2010. The modelling is not definitive, and does not consider later, more long-term flow testing (2011–2012), because the necessary down-hole data are lacking. However, results indicate that the evolution of the temperature conditions can be explained by these models. If the magma was emplaced during the most recent Krafla volcanic episode 25–35 years ago, the intrusion must have a thickness of at least 50–100m. The effective thickness of the permeable layer is estimated to be about 45m and its equilibrium temperature to be 390–400°C. No direct contact of the fluid with the magma is needed to explain the superheated steam discharged by the well. The situation near the bottom of the well clearly warrants further study, both through more advanced modelling and input of further data. The IDDP-1 well had to be quenched in July 2012. Whether it can maintain in the long-term the high energy output (15–40MWe), achieved during discharge testing, depends on sufficient recharge and efficient heat-exchange, if it can be rehabilitated. Carefully executed reinjection may be the solution if long-term recharge is not sufficient. 2014 0375-6505 https://doi.org/10.1016/j.geothermics.2013.05.003 Geothermics 49 49-57 Geothermal, Krafla, IDDP-1, Magma intrusion, Temperature conditions, Modelling, Superheated steam https://www.sciencedirect.com/science/article/pii/S0375650513000400 Iceland Deep Drilling Project:The first well, IDDP-1, drilled into Magma Gudni Axelsson Thorsteinn Egilson Sigrídur Sif Gylfadóttir article https://doi.org/10.4319/lo.2014.59.5.1621 From November 2006 to January 2010, a sediment trap that was cleared monthly was deployed in Lake Challa, a deep stratified freshwater lake on the eastern slope of Mt. Kilimanjaro in southern Kenya. Geochemical data from sediment trap samples were compared with a broad range of limnological and meteorological parameters to characterize the effect of single parameters on productivity and sedimentation processes in the crater basin. During the southern hemisphere summer (November—March), when the water temperature is high and the lake is biologically productive (nondiatom algae), calcite predominated in the sediment trap samples. During the “long rain” season (March—May) a small amount of organic matter and lithogenic material caused by rainfall appeared. This was followed by the cool and windy months of the southern hemisphere winter (June—October) when diatoms were the main component, indicating a diatom bloom initiated by improvement of nutrient availability related to upwelling processes. The sediment trap data support the hypothesis that the light—dark lamination couplets, which are abundant in Lake Challa cores, reflect seasonal delivery to the sediments of diatom-rich particulates during the windy months and diatom-poor material during the wet season. However, interannual and spatial variability in upwelling and productivity patterns, as well as El Niño—Southern Oscillation (ENSO)-related rainfall and drought cycles, exert a strong influence on the magnitude and geochemical composition of particle export to the hypolimnion of Lake Challa. 2014 https://doi.org/10.4319/lo.2014.59.5.1621 Limnology and Oceanography 59 1621-1636 5 https://aslopubs.onlinelibrary.wiley.com/doi/abs/10.4319/lo.2014.59.5.1621 Christian Wolff Iris Kristen-Jenny Georg Schettler Birgit Plessen Hanno Meyer Peter Dulski Rudolf Naumann Achim Brauer Dirk Verschuren Gerald H. Haug article Song20141 The T11 unconformity lies between the Qingshankou and Yaojia Formations in the post-rifting sequence of the Cretaceous Songliao Basin, NE China. It is intimately associated with petroleum reservoirs and considered to be a disconformity forming in the tectonic quiet stage. We present the interpretations from new seismic surveys and cored sections of the Cretaceous Continental Scientific Drilling borehole (CCSD-SK-1) in order to resolve the nature and origin of T11 unconformity. The T11 is often a low-angle unconformity with underlying Qingshankou Formation having been deformed and eroded prior to deposition of the Yaojia Formation. In the post-rift evolution of the basin it marks an abrupt change from a deep lake to shallow lake or subaerial environment, documented by reddening of the lacustrine mudstone, extinction of the ostracod assemblages and a great increase of coarse detrital inputs. The sharp change of depositional environment, the truncation of gentle folds and the cluster of volcanic and paleoearthquake activities, all happened simultaneously, immediately before the development of T11 unconformity, indicating a significant regional compressional uplift event in the basin. The timing of the T11 unconformity formation is within the interval 88-86.2. Ma. Correlations with coeval unconformities in other Cretaceous sedimentary basins in eastern Asia indicate that this compressional uplift coincided with an episode of global plate reorganization between the Eurasian and Paleo-Pacific plates that culminated at 88-87. Ma. During this short interval the northeast Asian margin, in eastern China, South Korea, Japan and Russian Far East experienced widespread violent volcanic and granite emplacement activity triggered by compression resulting from rapid and orthogonal slab subduction. The post-rift basin tectonic inversion occurred during T11 (Coniacian) time; thereafter the basin again evolved in an extension regime. Two subsidence phases in post-rift history took place as the direct consequence of Coniacian compression peak, which defined the distribution of oil sources and reservoirs. © 2014 Elsevier B.V. 2014 English 00401951 10.1016/j.tecto.2014.07.023 Tectonophysics 634 Elsevier B.V. 1-18 Department of Geology, China University of Petroleum (East China), China; Department of Marine Science, China University of Geoscience (Wuhan), China; Kosygin Institute of Tectonics and Geophysics, Far Eastern Branch, Russian Academy of Sciences, Khabarovsk, Russian Federation; Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (Nanjing), China Deposition; Geodynamics; Lakes; Petroleum reservoirs; Structural geology; Tectonics; Volcanoes, Basin inversions; Northeast Asia; Post-rift; Songliao basin; Unconformity, Petroleum reservoir engineering, Coniacian; depositional environment; depositional sequence; geodynamics; lacustrine deposit; paleoenvironment; plate tectonics; rifting; sedimentary basin; tectonic reconstruction; unconformity, China; Songliao Basin, Ostracoda https://www.scopus.com/inward/record.uri?eid=2-s2.0-84920546586&doi=10.1016%2fj.tecto.2014.07.023&partnerID=40&md5=3aca8eedd25b7b94c93896d3eddfec85 cited By 66 Y. Song J. Ren A.A. Stepashko J. Li article cp-10-1041-2014 Ash layers from explosive volcanic eruptions (i.e., tephra) represent isochronous surfaces independent from the environment in which they are deposited and the distance from their source. In comparison to eastern Beringia (nonglaciated Yukon and Alaska), few Plio-Pleistocene distal tephra are known from western Beringia (non-glaciated arctic and subarctic eastern Russia), hindering the dating and correlation of sediments beyond the limit of radiocarbon and luminescence methods. The identification of eight visible tephra layers (T0-T7) in sediment cores extracted from Lake El'gygytgyn, in the Far East Russian Arctic, indicates the feasibility of developing a tephrostratigraphic framework for this region. These tephra range in age from ca 45 ky to 2.2My old, and each is described and characterized by its major-, minor-, trace-element and Pb isotope composition. These data show that subduction-zone-related volcanism from the Kurile-Kamchatka-Aleutian Arc and Alaska Peninsula is the most likely source, with Pb isotope data indicating a Kamchatkan volcanic source for tephra layers T0-T5 and T7, while a source in the Aleutian Arc is possible for tephra T6. The location of Lake El'gygytgyn relative to potential source volcanoes (>1000 km) suggests these tephra are regionally distributed over a large area. These deposits provide a unique opportunity to correlate the highresolution paleoenvironmental records of Lake El'gygytgyn to other terrestrial paleoenvironmental archives from western Beringia and marine records from the western North Pacific and Bering Sea, and to move towards the development of a robust integrated framework between the continuous paleoclimatic records of Lake El'gygytgyn and other terrestrial and marine records in NE Eurasia. © Author(s) 2014. 2014 English 18149324 10.5194/cp-10-1041-2014 Climate of the Past 10 European Geosciences Union 1041-1062 GEOMAR Helmholtz-Zentrum für Ozeanforschung Kiel, Wischhofstr. 1-3, 24148 Kiel, Germany; Department of Earth and Atmospheric Sciences, 1-26 Earth Sciences Building, University of Alberta, Edmonton, AB T6G 2E3, Canada; Department of Geography and Earth Sciences, Aberystwyth University, Llandinam Building, Aberystwyth, SY23 3DB, United Kingdom; Institute of Volcanology and Seismology, Petropavlovsk-Kamchatsky, Russian Federation; University of Cologne, Institute for Geology and Mineralogy, Cologne, Germany; School of Geography, Archaeology and Palaeoecology, Queen's University, Belfast, United Kingdom 3 Beringia; chronostratigraphy; core analysis; explosive volcanism; lead isotope; luminescence; paleoclimate; paleoenvironment; Pleistocene; Pliocene; tephra; tephrochronology; volcanic ash; volcanic eruption, Alaska; Aleutian Islands; Arctic; Bering Sea; Canada; Chukchi; Elgygytgyn Lake; Kamchatka; Kuril Islands; Pacific Ocean; Pacific Ocean (Northwest); Russian Far East; Russian Federation; Sakhalin; United States; Yukon Territory https://cp.copernicus.org/articles/10/1041/2014/ cited By 11 C. Bogaard B. J. L. Jensen N. J. G. Pearce D. G. Froese M. V. Portnyagin V. V. Ponomareva V. Wennrich article FRIDLEIFSSON2014119 Preparation has begun for drilling the second deep IDDP well into the saline Reykjanes high-temperature field in SW-Iceland. The site selection for the IDDP-2 drillhole is under review and the prime candidate is essentially the same as the 1st priority site suggested for the Reykjanes field in 2003. More recent drillhole data and new MT surveys have amplified the justification for selecting that site. Deep drilling to 4–5km depth is an important part of the HS Orka exploration strategy for enhanced power production, either by direct use of high energy steam, or by attempting to enhance the field performance by re-injecting geothermal fluid deep into very hot rocks. Pending on several decisions and development in Iceland, outside the control of the IDDP energy consortium, the IDDP-2 well might possibly be drilled to 4–5km depth as early as 2014. 2014 English 0375-6505 https://doi.org/10.1016/j.geothermics.2013.05.006 Geothermics 49 119-126 HS Orka hf, Brekkustígur 36, 260 Reykjanesbær, Iceland; ISOR, Iceland GeoSurvey, Grensásvegur 9, 108 Reykjavík, Iceland; Department of Earth Sciences, University of California, Riverside, CA 92521-0423, United States Supercritical fluids, Iceland Deep Drilling Project, IDDP-2 well at Reykjanes, Black smoker analog https://www.sciencedirect.com/science/article/pii/S0375650513000436 Iceland Deep Drilling Project:The first well, IDDP-1, drilled into Magma G.Ó. Friðleifsson O. Sigurdsson D. Þorbjörnsson R. Karlsdóttir Þ. Gíslason A. Albertsson W.A. Elders article Wagner201419 The Scientific Collaboration on Past Speciation Conditions in Lake Ohrid (SCOPSCO) project is an international research initiative to study the influence of major geological and environmental events on the biological evolution of lake taxa. SCOPSCO drilling campaigns were carried out in 2011 and 2013. In 2011 we used gravity and piston coring at one of the five proposed drill sites, and in 2013 we undertook deep drilling with the Deep Lake Drilling System (DLDS) of Drilling, Observation and Sampling of the Earth's Continental Crust (DOSECC). In April and May 2013, a total of 2100m sediments were recovered from four drill sites with water depths ranging from 125 to 260 m. The maximum drill depth was 569m below the lake floor in the centre of the lake. By retrieving overlapping sediment sequences, 95% of the sediment succession was recovered. Initial data from borehole logging, core logging and geochemical measurements indicate that the sediment succession covers > 1.2 million years (Ma) in a quasi-continuous sequence. These early findings suggest that the record from Lake Ohrid will substantially improve the knowledge of long-term environmental change and short-term geological events in the northeastern Mediterranean region, which forms the basis for improving understanding of the influence of major geological and environmental events on the biological evolution of endemic species. © Author(s) 2014. Article 2014 English 18168957 10.5194/sd-17-19-2014 Scientific Drilling Integrated Ocean Drilling Program 19 – 29 17 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84900450565&doi=10.5194%2fsd-17-19-2014&partnerID=40&md5=54b32b0af1187a0f3bb6ff3099eb9d36 Cited by: 56; All Open Access, Gold Open Access, Green Open Access B. Wagner T. Wilke S. Krastel G. Zanchetta R. Sulpizio K. Reicherter M.J. Leng A. Grazhdani S. Trajanovski A. Francke K. Lindhorst Z. Levkov A. Cvetkoska J.M. Reed X. Zhang J.H. Lacey T. Wonik H. Baumgarten H. Vogel article Kenkmann2014156 The formation of impact craters is a highly dynamic and complex process that subjects the impacted target rocks to numerous types of deformation mechanisms. Understanding and interpreting these styles of micro-, meso- and macroscale deformation has proved itself challenging for the field of structural geology. In this paper, we give an overview of the structural inventory found in craters of all size ranges on Earth, and look into the structures of craters on other planetary bodies. Structural features are discussed here that are caused by i) extremely high pressures and temperatures that occur during the initial passage of the shock wave through the target rock and projectile, ii) the resulting flow field in the target that excavates and ejects rock materials, and iii) the gravitationally induced modification of the crater cavity into the final crater form. A special focus is put on the effects that low-angle impacting bodies have on crater formation. We hope that this review will help both planetary scientists and structural geologists understand the deformation processes and resulting structures generated by meteorite impact. © 2014. 2014 10.1016/j.jsg.2014.01.015 Journal of Structural Geology 62 156-182 Institut für Geo- und Umweltnaturwissenschaften - Geologie, Albert-Ludwigs-Universität Freiburg, Albertstraße 23-B, D-79104 Freiburg, Germany https://www.scopus.com/inward/record.uri?eid=2-s2.0-84896866618&doi=10.1016%2fj.jsg.2014.01.015&partnerID=40&md5=4d34785764a78d1ccfcd4471a83f9006 cited By 124 T. Kenkmann M.H. Poelchau G. Wulf article Cvetkoska2014145 The genus Surirella is highly diverse and many taxa are reported as endemic, especially from ancient lakes and tropical continental regions. In ancient Lake Ohrid, 25 different Surirella species have been identified by different authors, five are considered to be endemic for the lake. In contrast, research on its sister Lake Prespa has been less rigorous and data for recent and fossil species of Surirella is very sparse. The number of Surirella taxa reported from Lake Prespa is 11; only one is considered an endemic for both lakes, Ohrid and Prespa. In this study, taxa from the genus Surirella were observed in a number of recent and fossil samples from Lake Prespa. Two taxa possess unique characters that distinguish them from known species. Their formal descriptions, based on detailed LM and SEM observations, are presented here. Surirella subrotunda sp. nov. is differentiated from other similar species by its valve outline, size, and shape of median area; it has been observed only in fossil diatom samples from core Co1215 recovered from Lake Prespa. Surirella parahelvetica sp. nov. is distinguished by its size, valve outline, number of alar canals and stria density. © 2014 Magnolia Press. Article 2014 English 11793155 10.11646/phytotaxa.156.3.5 Phytotaxa 156 Magnolia Press 145 – 155 3 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84901921174&doi=10.11646%2fphytotaxa.156.3.5&partnerID=40&md5=8305453713fd98a98e3aa00e98446022 Cited by: 4 Aleksandra Cvetkoska Zlatko Levkov Paul B. Hamilton article Raschke2014978 El'gygytgyn is a 3.6 Ma, 18 km diameter, impact crater formed in an approximately 88 Ma old volcanic target in Northeast Siberia. The structure has been the subject of a recent ICDP drilling project. In parallel to those efforts, a Russian-German expedition was undertaken in summer 2011 to investigate the permafrost soil, lake terraces, and the volcanic rocks of the southern and eastern crater rim. This provided the unique opportunity for mapping and sampling of the volcanic target rocks around a large part of this complex impact structure. Samples from 43 outcrops were collected and analyzed petrographically and geochemically. The results were combined with earlier mapping outcomes to create a new geological map of this impact structure and its immediate environs, at the scale of 1:50,000. Compositions of our rock suites are compared with the lithologies of the 2009 ICDP drill core. The ignimbrite described as lower bedrock in the ICDP drill core shows petrographically and chemically strong similarities to the rhyolitic and rhyodacitic ignimbrites observed on surface. The suevite sequence exposed in the ICDP drill core is a mixture of all observed target rocks at their respective proportions in the area. In contrast to previous studies, the calculated average target composition of El'gygytgyn takes the contribution of the basic target rocks into consideration: mafic and intermediate rocks approximately 7.5%, and felsic rocks approximately 92.5%. © The Meteoritical Society, 2014. 2014 English 10869379 10.1111/maps.12306 Meteoritics and Planetary Science 49 University of Arkansas 978-1006 Museum für Naturkunde Berlin, Invalidenstraße 43, Berlin, 10115, Germany; Humboldt-Universität zu Berlin, Unter den Linden 6, Berlin, 10099, Germany 6 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84902269191&doi=10.1111%2fmaps.12306&partnerID=40&md5=1130e940216cb8edfc9d05071c27e569 cited By 6 U. Raschke P.T. Zaag R.T. Schmitt W.U. Reimold article Glombick2014872 Geological and geophysical evidence is presented for a newly discovered, probable remnant complex impact structure. The structure, located near Bow City, southern Alberta, has no obvious morphological expression at surface. The geometry of the structure in the shallow subsurface, mapped using downhole geophysical well logs, is a semicircular structural depression approximately 8 km in diameter with a semicircular uplifted central region. Detailed subsurface mapping revealed evidence of localized duplication of stratigraphic section in the central uplift area and omission of strata within the surrounding annular region. Field mapping of outcrop confirmed an inlier of older rocks present within the center of the structure. Evidence of deformation along the eastern margin of the central uplift includes thrust faulting, folding, and steeply dipping bedding. Normal faults were mapped along the northern margin of the annular region. Isopach maps reveal that structural thickening and thinning were accommodated primarily within the Belly River Group. Evidence from legacy 2-D seismic data is consistent with the subsurface mapping and reveals additional insight into the geometry of the structure, including a series of listric normal faults in the annular region and complex faulting within the central uplift. The absence of any ejecta blanket, breccia, suevite, or melt sheet (based on available data) is consistent with the Bow City structure being the remnant of a deeply eroded, complex impact structure. Accordingly, the Bow City structure may provide rare access and insight into zones of deformation remaining beneath an excavated transient crater in stratified siliciclastic target rocks. © The Meteoritical Society, 2014. 2014 10.1111/maps.12296 Meteoritics and Planetary Science 49 872-895 Alberta Geological Survey, Alberta Energy Regulator, 402 Twin Atria Building, 4999 - 98 Avenue, Edmonton, Alberta, T6B 2X3, Canada; Department of Physics, Institute for Geophysical Research, CCIS 4-183, University of Alberta, Edmonton, Alberta, T6G 2E1, Canada; OptaSense Canada, 10911 - 50 Street SE, Calgary, Alberta, T2C 3E5, Canada; Schlumberger Information Solutions, Kirkhill House, Aberdeen Business Park, Dyce, Aberdeen, United Kingdom; Box 1403, Fort Macleod, Alberta, T0L 0Z0, Canada 5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84900542313&doi=10.1111%2fmaps.12296&partnerID=40&md5=0b2383e1935863659cd5f9b5b6ba85f4 cited By 5 P. Glombick W. Xie T. Bown B. Hathway C. Banks article FRIDLEIFSSON20142 Calculations discussed in the Iceland Deep Drilling Project feasibility study in 2003 indicated that, for same volumetric flow rate of steam, a geothermal well producing from natural supercritical fluid would have the potential to generate power outputs an order of magnitude greater than from conventional high-temperature wells (240–340°C). To reach supercritical hydrous fluid conditions in natural geothermal systems requires deep drilling to a minimum depth of some 3.5–5km were temperature conditions can be expected to range between 400 and 600°C in reasonably active high-temperature fields. Three geothermal fields in Iceland, Reykjanes, Hengill and Krafla, were selected as suitable locations for deep drilling to test this concept in search of natural supercritical geothermal fluid systems. 2014 0375-6505 https://doi.org/10.1016/j.geothermics.2013.03.004 Geothermics 49 2-8 Iceland Deep Drilling Project, Supercritical geothermal fluid systems https://www.sciencedirect.com/science/article/pii/S0375650513000217 Iceland Deep Drilling Project:The first well, IDDP-1, drilled into Magma G.Ó. Friðleifsson W.A. Elders A. Albertsson article Junginger20141 The water-level record from the 300. m deep paleo-lake Suguta (Northern Kenya Rift) during the African Humid Period (AHP, 15-5. ka BP) helps to explain decadal to centennial intensity variations in the West African Monsoon (WAM) and the Indian Summer Monsoon (ISM). This water-level record was derived from three different sources: (1) grain size variations in radiocarbon dated and reservoir corrected lacustrine sediments, (2) the altitudes and ages of paleo-shorelines within the basin, and (3) the results of hydro-balance modeling, providing important insights into the character of water level variations (abrupt or gradual) in the amplifier paleo-Lake Suguta. The results of these comprehensive analyses suggest that the AHP highstand in the Suguta Valley was the direct consequence of a northeastwards shift in the Congo Air Boundary (CAB), which was in turn caused by an enhanced atmospheric pressure gradient between East Africa and India during a northern hemisphere insolation maximum. Rapidly decreasing water levels of up to 90. m over less than a hundred years are best explained by changes in solar irradiation either reducing the East African-Indian atmospheric pressure gradient and preventing the CAB from reaching the study area, or reducing the overall humidity in the atmosphere, or a combination of both these effects. In contrast, although not well documented in our record we hypothesize a gradual end of the AHP despite an abrupt change in the source of precipitation when a decreasing pressure gradient between Asia and Africa prevented the CAB from reaching the Suguta Valley. The abruptness was probably buffered by a contemporaneous change in precession producing an insolation maximum at the equator during October. Whether or not this is the case, the water-level record from the Suguta Valley demonstrates the importance of both orbitally-controlled insolation variations and short-term changes in solar irradiation as factors affecting the significant water level variations in East African rift lakes. © 2013 Elsevier B.V. Article 2014 English 00310182 10.1016/j.palaeo.2013.12.007 Palaeogeography, Palaeoclimatology, Palaeoecology 396 1 – 16 Atlantic Ocean; Congo Margin; Kenya; Rift Valley; Suguta Valley; Congo; East African Rift; Kenya; Kenya Rift; Rift Valley; Suguta Valley; atmospheric pressure; irradiation; migration determinant; paleoatmosphere; paleolimnology; pressure gradient; radiocarbon dating; shoreline; solar radiation; water level; atmospheric pressure; grain size; highstand; insolation; irradiation; monsoon; Northern Hemisphere; pressure gradient; rift zone; summer; water level https://www.scopus.com/inward/record.uri?eid=2-s2.0-84893006703&doi=10.1016%2fj.palaeo.2013.12.007&partnerID=40&md5=7a04c40bea0b1aaf38dd48011c0448e0 Cited by: 58 Annett Junginger Sybille Roller Lydia A. Olaka Martin H. Trauth article salminen2014travertine 2014 Precambrian Research 255 Elsevier 181--201 PE Salminen AT Brasier JA Karhu VA Melezhik article Wang20142512 Otoliths are biogenic carbonate minerals in the inner ear of teleost fish, whose compositions can record the physical and chemical conditions of the ambient water environment inhabited by individual fish. In this research, the fishbones and otoliths of naked carp sampled near the Bird Island, offshore Lake Qinghai, were dated and analyzed for mineralogy and microchemical compositions. Comparing the microchemical compositions of ancient otoliths with those of modern otoliths, we conclude that the ancient naked carps inhabited a relict lake formed when the lake shrank from a high lake level, by combining with the AMS-14C ages of fishbones and otoliths, the stratigraphy and surrounding topography of the sample site. AMS-14C dating results of ancient fishbones and otoliths show that these naked carps lived from 680 to 300 years ago, i.e. during the Ming Dynasty of China. The X-ray diffraction (XRD) patterns demonstrate that the ancient lapillus is composed of pure aragonite, identical to modern one, indicating that the mineral of lapillus didn’t change after a long time burial and that the ancient lapillus is suitable for comparative analysis thereafter. Microchemical results show that both ratios of Mg/Ca ((70.12±18.50)×10−5) and δ18O ((1.76±1.03)‰) of ancient lapilli are significantly higher than those of modern lapilli (average Mg/Ca=(3.11±0.41)× 10−5 and δ18O=(−4.82±0.96)‰). This reflects that the relict water body in which the ancient naked carp lived during the Ming Dynasty was characterized by higher Mg/Ca and δ18O ratios than modern Lake Qinghai, resulting from strong evaporation after being isolated from the main lake, similar to today’s Lake Gahai. Based upon the stratigraphy and altitude of naked carp remains, it can be inferred that the altitude of lake level of Lake Qinghai reached at least 3202 m with a lake area of 4480 km2 during the Ming Dynasty, approximately ∼5% larger than it is today. © 2014, Science China Press and Springer-Verlag Berlin Heidelberg. Article 2014 English 16747313 10.1007/s11430-014-4836-1 Science China Earth Sciences 57 Science Press (China) 2512 – 2521 10 Carbonate minerals; Fish; Offshore oil well production; Stratigraphy; Topography; Water levels; Fishbone; Lake levels; Lake Qinghai naked carps; lapillus; Oxygen isotopes; Lakes https://www.scopus.com/inward/record.uri?eid=2-s2.0-84920256247&doi=10.1007%2fs11430-014-4836-1&partnerID=40&md5=de1787606bcfaabf1dd3a960a02c1d8f Cited by: 10 Yujiao Wang Zhangdong Jin Ling Zhou Fuchun Li Fei Zhang Liumei Chen XinNing Qiu RuGui Qi article HJARTARSON201483 When a dry steam containing volatile chloride cools to saturation temperature, the compound dissolves in the condensate and forms hydrochloric acid. This can have tremendous consequences for equipment as hydrochloric acid aggressively attacks steel and other metals, causing severe pitting corrosion, crystalline corrosion and stress corrosion cracking of stainless steel components. The Icelandic Deep Drilling Project is dealing with extreme circumstances with high enthalpy, superheated steam possibly containing hydrogen chloride. Successful corrosion mitigation is essential for the feasibility of the development. The goal of this work is to examine different technologies to utilize such a steam, with regard to exergy conservation. 2014 0375-6505 https://doi.org/10.1016/j.geothermics.2013.08.008 Geothermics 49 83-89 IDDP, Volatile chloride, Corrosion mitigation, Superheated geothermal steam https://www.sciencedirect.com/science/article/pii/S0375650513000709 Iceland Deep Drilling Project:The first well, IDDP-1, drilled into Magma Steindór Hjartarson Guðrún Sævarsdóttir Kristinn Ingason Bjarni Pálsson William S. Harvey Halldór Pálsson article Cukur2014201 Sediments of Lake Van, Turkey, preserve one of the most complete records of continental climate change in the Near East since the Middle Pleistocene. We used seismic reflection profiles to infer past changes in lake level and discuss potential causes related to changes in climate, volcanism, and regional tectonics since the formation of the lake ca. 600 ka ago. Lake Van’s water level ranged by as much as 600 m during the past ~600 ka. Five major lowstands occurred, at ~600, ~365–340, ~290–230, ~150–130 and ~30–14 ka. During Stage A, between about 600 and 230 ka, lake level changed dramatically, by hundreds of meters, but phases of low and high stands were separated by long time intervals. Changes in the lake level were more frequent during the past ~230 ka, but less dramatic, on the order of a few tens of meters. We identified period B1 as a time of stepwise transgressions between ~230 and 150 ka, followed by a short regression between ca. 150 and 130 ka. Lake level rose stepwise during period B2, until ~30 ka. During the past ~30 ka, a regression and a final transgression occurred, each lasting about 15 ka. The major lowstand periods in Lake Van occurred during glacial periods, suggesting climatic control on water level changes (i.e. greatly reduced precipitation led to lower lake levels). Although climate forcing was the dominant cause for dramatic water level changes in Lake Van, volcanic and tectonic forcing factors may have contributed as well. For instance, the number of distinct tephra layers, some several meters thick, increases dramatically in the uppermost ~100 m of the sediment record (i.e. the past ~230 ka), an interval that coincides largely with low-magnitude lake level fluctuations. Tectonic activity, highlighted by extensional and/or compressional faults across the basin margins, probably also affected the lake level of Lake Van in the past. © 2014, Springer Science+Business Media Dordrecht. 2014 English 09212728 10.1007/s10933-014-9788-0 Journal of Paleolimnology 52 Kluwer Academic Publishers 201-214 GEOMAR Helmholtz Centre for Ocean Research Kiel, Wischhofstr. 1-3, Kiel, 24148, Germany; Institute of Geosciences, Christian-Albrechts-Universität zu Kiel, Otto-Hahn-Platz 1, Kiel, 24118, Germany; Department of Water Resources and Drinking Water, Eawag, Swiss Federal Institute of Aquatic Science and Technology, Überlandstrasse 133, Dübendorf, 8600, Switzerland; Atmosphere and Ocean Research Institute, The University of Tokyo, 5-1-5 Kashiwa-noha, Kashiwa-shi, Chiba 277-8564, Japan; EMCOL and Department of Geological Engineering, Istanbul Technical University, Maslak, Istanbul, 34469, Turkey 3 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84939882522&doi=10.1007%2fs10933-014-9788-0&partnerID=40&md5=2d8aaa3104e927a925417007214154c3 cited By 32 D. Cukur S. Krastel H.U. Schmincke M. Sumita Y. Tomonaga M. Namık Çağatay article Li201425 Lake Qinghai, the largest saline lake in China, is a closed-basin lake with a salinity of 16. g/L and is situated in the sensitive semi-arid zone between the Asian monsoon-controlled area and the westerly jet stream-influenced area. With the support of the International Continental Drilling Program (ICDP), Lake Qinghai was drilled in 2005 using the ICDP GLAD800 drilling system. Two ostracod species, i.e., Limnocythere inopinata and Eucypris mareotica, were found only in the upper 5.15. m of the drilled core 1F, covering 12. ka, where the depths of 5.15 to 3.15. m (12.0-7.4. ka) are dominated by E. mareotica and the depths of 3.15 to 0. m (7.4. ka-present) are dominated by L. inopinata.The presence of the ostracod Eucypris mareotica was related to the high salinity of the water (exceeding 30g/L), and the dominant species of ostracod (Limnocythere inopinata) was related to the brackish water (3-16g/L) in the Lake Qinghai area (Li et al., 2010). The changes in the carbon isotope in the modern ostracod shells were related to the water salinity and productivity on the lake bottom in Lake Qinghai (Li et al., 2012). On this basis, this study evaluated the changes in lake salinity and productivity and their relation to climatic change using changes in the relative abundances of ostracod fossil species assemblages and the stable carbon isotope in ostracod shells from core 1F and other published data (e.g., total organic carbon content, δ13CTOC and ice core δ18O).The single occurrence of ostracod Eucypris mareotica and the highest average δ13C values (-0.2‰) in their shells indicated that the lake salinity and productivity were very high, a phenomenon that was related to the high temperature and low lake level (caused by intense evaporation even though the precipitation increased sharply) in the early Holocene. The deceased abundance of ostracod E. mareotica and the lowest average δ13C values (-2.0‰) in ostracod shells showed that the lake salinity and productivity decreased because of the increased lake level and decreased temperatures in the middle Holocene. Finally, the lake level decreased, but the water salinity and the lake productivity gradually increased because of the high E/I ratio related to the increased temperature in the late Holocene. © 2014 Elsevier B.V. Article 2014 English 00310182 10.1016/j.palaeo.2014.04.017 Palaeogeography, Palaeoclimatology, Palaeoecology 407 Elsevier 25 – 33 China; Qinghai; Qinghai Lake; Qinghai-Xizang Plateau; brackish water; carbon isotope; climate variation; drilling; fossil assemblage; Holocene; jet stream; lake level; monsoon; ostracod; primary production; saline lake; salinity; semiarid region; temperature effect; westerly https://www.scopus.com/inward/record.uri?eid=2-s2.0-84900791373&doi=10.1016%2fj.palaeo.2014.04.017&partnerID=40&md5=7f9dba28fcb82966946c694eea5a4757 Cited by: 38 Xiangzhong Li Weiguo Liu article THORHALLSSON201416 The aim of the Iceland Deep Drilling Projects (IDDP) was to drill to a depth of 4–5km in known high-temperature areas to investigate their roots. The paper describes the design of the “generic” IDDP well and what the plans were. The challenges are to drill a large well with five cemented casing strings to 4500m into a reservoir which can have a temperature of 400–600°C. In 2009 well IDDP-1 was drilled according to these plans but could not reach below 2100m due to the intersection of magma, as will be described in other papers in this special issue of Geothermics. The paper is thus for the historical record of the original design premises and intentions. 2014 0375-6505 https://doi.org/10.1016/j.geothermics.2013.08.004 Geothermics 49 16-22 Iceland Deep Drilling, Well design, Supercritical steam https://www.sciencedirect.com/science/article/pii/S0375650513000606 Iceland Deep Drilling Project:The first well, IDDP-1, drilled into Magma S. Thórhallsson B. Pálsson S. Hólmgeirsson K. Ingason M. Matthíasson H.Á. Bóasson H. Sverrisson article Jean2014119 The Snake River Plain represents 17 m.y. of volcanic activity that took place as the North American continent migrated over a relatively fixed magma source, or hotspot. We present new Pb, Sr, and Nd data for a suite of 25 basalts collected from Western and Central Snake River Plain (SRP). The new isotope data, combined with previously published data from the SRP, provide a traverse of the Wyoming craton margin, from the 87Sr/86Sr = 0.706 line boundary of western SRP with Phanerozoic accreted terranes, east through the central and eastern SRP, to the Yellowstone Plateau. Low-K basalts from the western SRP, overlain by high-K basalts, provide a temporal record of regional source variation from ~16.8 to 0.2 Ma. Principal Component Analysis (PCA) of the new and previously published SRP basalt Pb isotopes reveals that &gt;97% of the total variability is accounted for by mixing between three end-members and is consistent with a sublithospheric Yellowstone hotspot mantle source with a radiogenic isotope composition similar to the mantle source of the early Columbia River Basalt Group (CRBG) and two continental lithosphere end-members, heterogeneous in age and composition. We use the SRP Pb, Sr, and Nd isotope data to model the Yellowstone Hotspot-continental lithosphere interaction by three component mixing between two continental lithospheric components, Archean lithosphere (CL1) that represents older lithosphere underlying the Yellowstone Plateau in the east, and Paleoproterozoic lithosphere (CL2) representing the younger lithosphere underlying the SRP in the west near the craton margin, and a sublithospheric end-member, representing the Yellowstone hotspot (PL). The results suggest a continuous flow of PL material westward as the NA continental lithosphere migrated over the upwelling hotspot along a shoaling gradient in the sub-continental mantle lithosphere. The model shows a decrease in Total Lithosphere end-members (CL1 + CL2) and the Lithosphere Ratio (CL1/CL2), from the craton interior at Yellowstone toward its western margin, consistent with geologic and geophysical evidence that the continental lithosphere beneath the SRP decreases in age and thickness from east to west. The Lithosphere Ratio shows step-like decreases from Yellowstone in the east to the 87Sr/86Sr = 0.706 line in the west, indicating that the SRP cuts across geochemically distinct parcels of lithospheric mantle, consistent with terrane accretion models for the craton margin. In the western SRP, young high-K basalts have a lower mass fraction of Total Lithospheric compared to the underlying low-K tholeiites, but the same Lithosphere Ratio, consistent with a recent (700-900 ka) decrease in lithosphere contribution between eruption of early low- and younger high-K basalts. © 2013 Elsevier B.V. 2014 English 0012821X 10.1016/j.epsl.2013.12.012 Earth and Planetary Science Letters 389 119-131 Department of Geology, Utah State University, 4505 Old Main Hill, Logan, UT 84322-4500, United States; Department of Geological Sciences, San Diego State University, San Diego, CA 92182-1020, United States; Institut für Mineralogie, Leibniz Universität, Hannover, 30167, Germany Columbia river basalts; Continental lithosphere; Geophysical evidence; Plume dynamics; Snake river plains; Total variabilities; Volcanic activities; Yellowstones, Basalt; Isotopes; Lead; Lithology; Mixing; Principal component analysis; Rivers, Strontium, alkali basalt; continental lithosphere; craton; hot spot; igneous geochemistry; isotopic analysis; isotopic composition; lead isotope; neodymium isotope; plume; strontium isotope; terrane; tholeiitic basalt, Idaho; Snake River Plain; United States; Wyoming; Yellowstone Volcanic Plateau https://www.scopus.com/inward/record.uri?eid=2-s2.0-84892174388&doi=10.1016%2fj.epsl.2013.12.012&partnerID=40&md5=060460e1f77f9c5696587e73d525495b cited By 24 M.M. Jean B.B. Hanan J.W. Shervais article Zhang20143013 We incorporate body-wave arrival time and surface-wave dispersion data into a joint inversion for three-dimensional P-wave and S-wave velocity structure of the crust surrounding the site of the San Andreas Fault Observatory at Depth. The contributions of the two data types to the inversion are controlled by the relative weighting of the respective equations. We find that the trade-off between fitting the two data types, controlled by the weighting, defines a clear optimal solution. Varying the weighting away from the optimal point leads to sharp increases in misfit for one data type with only modest reduction in misfit for the other data type. All the acceptable solutions yield structures with similar primary features, but the smaller-scale features change substantially. When there is a lower relative weight on the surface-wave data, it appears that the solution over-fits the body-wave data, leading to a relatively rough Vs model, whereas for the optimal weighting, we obtain a relatively smooth model that is able to fit both the body-wave and surface-wave observations adequately. © 2014, Springer Basel. 2014 English 00334553 10.1007/s00024-014-0806-y Pure and Applied Geophysics 171 Birkhauser Verlag AG 3013-3022 Laboratory of Seismology and Earth’s Interior, School of Earth and Space Sciences, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026, China; Earth and Environmental Sciences, Los Alamos National Laboratory, Los Alamos, NM 87545, United States; ISTerre, CNRS, IRD, Université Joseph Fourier, Saint-Martin-d’Hères, France; Department of Geoscience, University of Wisconsin-Madison, Madison, WI 53706, United States 11 Economic and social effects; Seismic waves; Shear waves; Strike-slip faults; Surface waves; Wave propagation, Optimal solutions; Optimal weighting; Relative weights; S-wave velocity structure; San Andreas fault; Seismic structure; Surface wave data; Surface wave dispersion, Dispersion (waves), arrival time; body wave; inverse problem; P-wave; S-wave; San Andreas Fault; surface wave; three-dimensional modeling; velocity structure; wave dispersion https://www.scopus.com/inward/record.uri?eid=2-s2.0-84911444202&doi=10.1007%2fs00024-014-0806-y&partnerID=40&md5=f686fc48b1cc1c18245e06c6a57c0266 cited By 35 H. Zhang M. Maceira P. Roux C. Thurber article MORTENSEN201431 The stratigraphy, alteration mineralogy and temperature conditions in well IDDP-1 were established through drill cutting analyses and geophysical logs. The stratigraphy comprises basaltic lava and hyaloclastite sequences extending to 1362m succeeded by an intrusive complex. Intrusions comprise basaltic dykes, dolerites and below 2020m, granophyre and felsites. Rhyolitic magma was intersected below 2100m. Alteration reflects cooling in the upper ∼1500m of the reservoir. Below 1600m temperature follows the boiling-point-depth curve. Alteration minerals are scarce in vicinity to the feed zone at 2035–2080m correlating with a superheated steam zone above the magma, but estimated bottom-hole temperature is ∼500°C. 2014 0375-6505 https://doi.org/10.1016/j.geothermics.2013.09.013 Geothermics 49 31-41 IDDP-1, Krafla, Alteration, Magma, Superheated conditions https://www.sciencedirect.com/science/article/pii/S0375650513000874 Iceland Deep Drilling Project:The first well, IDDP-1, drilled into Magma A.K. Mortensen Þ. Egilson B. Gautason S. Árnadóttir Á. Guðmundsson article Buckles2014106 The MBT/CBT palaeotemperature proxy uses the distribution of branched glycerol dialkyl glycerol tetraethers (brGDGTs), membrane lipids that are supposed to derive from soil bacteria, to reconstruct mean annual air temperature (MAAT). Applied successfully in coastal marine sediments, its extension to lake-sediment records with potentially high time resolution would greatly expand its utility. Over the last years, however, studies have indicated the presence of additional sources of brGDGTs within lake systems. To constrain the factors influencing the MBT/CBT palaeotemperature proxy in lakes, detailed investigation of brGDGT fluxes in a modern lake system is necessary to identify their potential sources. This study concentrates on Lake Challa, a permanently stratified crater lake in equatorial East Africa with limited catchment area. An almost 3-year time series of approximately monthly samples of settling particles, supplemented with a depth profile of suspended particulate matter (SPM) and sets of profundal surface-sediment and catchment soil samples, were analysed for both the 'living' intact polar lipids (IPLs) and 'fossil' core lipids (CLs) of GDGTs. We found that brGDGTs are produced in oxic, suboxic and anoxic zones of the water column, and in substantial amounts compared to influxes from catchment soils. Additional in situ production within the lake sediments is most probable, but cannot be definitely confirmed at this time. These lacustrine brGDGTs display a different response to temperature variation than soil-derived brGDGTs, signifying either a different physiological adaptation to changing conditions within the water column and/or a different composition of the respective bacterial communities. Using this specific relationship with temperature, a local calibration based on brGDGT distributions in SPM generates relatively accurate water temperature estimates from settling particles but fails for surface sediments. © 2014 Elsevier Ltd. Article 2014 English 00167037 10.1016/j.gca.2014.04.042 Geochimica et Cosmochimica Acta 140 Elsevier Ltd 106 – 126 Kilimanjaro [Tanzania]; Lake Challa; Tanzania; Bacteria (microorganisms); core analysis; lacustrine deposit; lacustrine environment; lipid; membrane; microbial community; paleotemperature; soil biota; suspended particulate matter; water temperature https://www.scopus.com/inward/record.uri?eid=2-s2.0-84902329365&doi=10.1016%2fj.gca.2014.04.042&partnerID=40&md5=492afc3ee3392a7e2ca7e1e2d31c6389 Cited by: 78; All Open Access, Green Open Access Laura K. Buckles Johan W.H. Weijers Dirk Verschuren Jaap S. Sinninghe Damsté article Gupta20145 We report here the salient features of the recently concluded International Continental Scientific Drilling Program (ICDP) workshop in Koyna, India. This workshop was a sequel to the earlier held ICDP workshop in Hyderabad and Koyna in 2011. A total of 49 experts (37 from India and 12 from 8 other countries) spent 3 days reviewing the work carried out during the last 3 years based on the recommendations of the 2011 workshop and suggesting the future course of action, including detailed planning for a full deep drilling proposal in Koyna, India. It was unanimously concluded that Koyna is one of the best sites anywhere in the world to investigate genesis of triggered earthquakes from near-field observations. A broad framework of the activities for the next phase leading to deep drilling has been worked out. 2014 English 18168957 10.5194/sd-18-5-2014 Scientific Drilling 18 Copernicus GmbH 5-9 National Disaster Management Authority, New Delhi, India; Ministry of Earth Sciences (MoES), Prithvi Bhavan, Lodi Road, New Delhi, 110003, India; Earthquake Science Center, U.S. Geological Survey, Menlo Park, CA, United States; CSIR-National Geophysical Research Institute, Hyderabad, 500007, India; National Center for Antarctic and Ocean Research, MoES, Goa, 403804, India Drilling; Energy resources, Continental scientific drillings; Course of action; Deep drilling; Detailed planning; Near fields; Salient features; Scientific deep-drilling; Triggered Earthquakes, Earthquakes https://www.scopus.com/inward/record.uri?eid=2-s2.0-84926341111&doi=10.5194%2fsd-18-5-2014&partnerID=40&md5=71c8b811e10d55f0cf059c4e861c61cc cited By 9 H. Gupta S. Nayak Y.J.B. Rao S. Rajan B.K. Bansal N. Purnachandra Rao S. Roy K. Arora R. Mohan V.M. Tiwari H.V.S. Satyanarayana P.K. Patro D. Shashidhar K. Mallika article Lisé-Pronovost2014110 A 106-m long sediment sequence from the maar lake Laguna Potrok Aike in southern Patagonia was recovered in the framework of the International Continental Scientific Drilling Program (ICDP) Potrok Aike maar lake Sediment Archive Drilling prOject (PASADO). About half of the sedimentary sequence is composed of mass movement deposits (MMDs) and the event-corrected record reaches back to 51,200calBP. Here we present a high-resolution rock-magnetic study revealing two sedimentary facies associated with MMDs and characterized by two different types of spurious gyroremanent magnetization (GRM) acquired during static alternating field demagnetization. The first rock-magnetic signature is detected in MMDs composed of reworked sand and tephra material. The signature consists of GRM acquired during demagnetization of the natural remanent magnetization (NRM) and other rock-magnetic properties typical of iron sulfides such as greigite. We interpret these intervals as authigenic formation of iron sulfides in suboxic conditions within the MMD. The second rock-magnetic signature consists of a series of 10 short intervals located on the top of MMDs characterized by GRM acquisition during demagnetization of the isothermal remanent magnetization (IRM). Based on geological, limnological, stratigraphic and climatic evidence these layers are interpreted as reflecting pedogenic hematite and/or goethite brought to the lake by runoff events related to precipitation and permafrost melt. The pedogenic iron minerals mobilized from the catchment most likely settled out of suspension on top of MMDs after a rapid remobilization event. The series of runoff events corresponds to periods of increased lacustrine productivity in Laguna Potrok Aike and are coeval within the limit of the chronology to warm periods of the Last Glacial as recorded in Antarctica, the deglaciation in the mid-latitudes of the Southern Hemisphere and enhanced precipitation during the Early Holocene in southeastern Patagonia. © 2014 Elsevier Ltd. Article 2014 10.1016/j.quascirev.2014.05.029 Quaternary Science Reviews 98 110 – 125 Argentina; Laguna Potrok Aike; Patagonia; Santa Cruz [Argentina]; Catchments; Demagnetization; Deposits; Geomagnetism; Iron; Lakes; Magnetization; Runoff; Sedimentology; Sediments; Stratigraphy; Lacustrine sediments; Laguna potrok aike; Mass movement; Paleo-environment; Rock magnetism; facies; geochronology; hematite; isotherm; lacustrine deposit; last glaciation; magnetization; paleoenvironment; precipitation (climatology); runoff; sedimentary sequence; sulfide; Sedimentary rocks https://www.scopus.com/inward/record.uri?eid=2-s2.0-84902986374&doi=10.1016%2fj.quascirev.2014.05.029&partnerID=40&md5=9c803f06f52f8358fea1d231957d4d3a Cited by: 14 A. Lisé-Pronovost G. St-Onge C. Gogorza G. Jouve P. Francus B. Zolitschka article Miller20147 Terrestrial fossil pollen records are frequently used to reveal the response of vegetation to changes in both regional and global climate. Here we present a fossil pollen record from sediment cores extracted from Lake Bosumtwi (West Africa). This record covers the last c. 520 thousand years (ka) and represents the longest terrestrial pollen record from Africa published to date. The fossil pollen assemblages reveal dynamic vegetation change which can be broadly characterized as indicative of shifts between savannah and forest. Savannah formations are heavily dominated by grass (Poaceae) pollen (>55%) typically associated with Cyperaceae, Chenopodiaceae-Amaranthaceae and Caryophyllaceae. Forest formations are palynologically more diverse than the savannah, with the key taxa occurring in multiple forest zones being Moraceae, Celtis, Uapaca, Macaranga and Trema. The fossil pollen data indicate that over the last c. 520ka the vegetation of lowland tropical West Africa has mainly been savannah; however six periods of forest expansion are evident which most likely correspond to global interglacial periods. A comparison of the forest assemblage composition within each interglacial suggests that the Holocene (11-0ka) forest occurred under the wettest climate, while the forest which occurred at the time of Marine Isotope Stage 7 probably occurred under the driest climate. © 2013 The Authors. Review 2014 English 02773791 10.1016/j.quascirev.2013.10.027 Quaternary Science Reviews 84 Elsevier Ltd 7 – 25 Forestry; Isotopes; Lakes; Plants; Pollen; Ashanti; Georgia; Ghana; Lake Bosumtwi; Savannah; United States; West Africa; Amaranthaceae; Caryophyllaceae; Celtis; Cyperaceae; Macaranga; Moraceae; Poaceae; Trema; Uapaca; Isotopes; Lakes; Vegetation; Assemblage composition; Ghana; Interglacial periods; Marine Isotope Stage 7; Pollen; Quaternary; Terrestrial pollen records; West Africa; forest; fossil record; global climate; Holocene; interglacial; marine isotope stage; pollen; Quaternary; savanna; vegetation; Forestry https://www.scopus.com/inward/record.uri?eid=2-s2.0-84889046774&doi=10.1016%2fj.quascirev.2013.10.027&partnerID=40&md5=6cbdcaa0fc3f8cdbbddfb43253686a5e Cited by: 48; All Open Access, Green Open Access, Hybrid Gold Open Access Charlotte S. Miller William D. Gosling article Lorenschat2014139 Ancient lakes, which are important centres of biodiversity and endemism, are threatened by a wide variety of human impacts. To assess environmental impact on ancient Lake Ohrid we have taken short sediment cores from two contrasting site locations, comprising a site of urban pollution and an apparently pristine area. Recent impacts on water quality and ecology were assessed using sediment, geochemical, ostracode, and diatom data derived from analysis of two 210Pb-dated sediment cores spanning the period from 1918 to 2009. According to the index of geoaccumulation, sediments were often moderately contaminated with As. Fe and Ni concentrations often exceeded reported maximum limits above which harmful effects on sediment-dwelling organisms are expected. Productivity in the (pristine) south-eastern part of Lake Ohrid (Sveti Naum) is generally lower than in the north, probably due to the strong influence of spring discharge. Low ostracode and diatom concentrations, low abundance of the epilimnetic diatom Cyclotellaocellata, and low values of TOC and TIC indicate a lower productivity from the early 1920s to the late 1980s. Since the mid 1970s, increased relative abundance of C. ocellata and increasing diatom concentration indicate increasing productivity in the south-eastern part. Rising numbers of ostracode valves and higher TIC and TOC contents in both sediment cores indicate an increase in productivity during the late 1980s. A slight increase in productivity near Sveti Naum continued from the early 1990s until 2009, witnessed by rising TC, TIC, and TOC content and a generally high number of ostracode valves and ostracode diversity. The area near the City of Struga (site of urban pollution) is also characterized by rising TOC and TIC contents and, furthermore, by increasing Cu, Fe, Pb, and Zn concentrations since the early 1990s. The recent reduction in the number of ostracode valves and ostracode diversity is probably caused by a higher heavy metal load into the lake. This suggests that living conditions for the endemic species in Lake Ohrid have become less favourable in the northern part of the lake, which might threaten the unique flora and fauna of Lake Ohrid. © 2014, Springer Science+Business Media Dordrecht. Article 2014 English 09212728 10.1007/s10933-014-9783-5 Journal of Paleolimnology 52 Kluwer Academic Publishers 139 – 154 3 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84926426996&doi=10.1007%2fs10933-014-9783-5&partnerID=40&md5=2cb517f64a462a24873103a1949d5fad Cited by: 7; All Open Access, Green Open Access Julia Lorenschat Xiaosen Zhang Flavio S. Anselmetti Jane M. Reed Martin Wessels Antje Schwalb article Stierle20141869 We perform a detailed synthetic study on the resolution of non-double-couple (non-DC) components in the seismic moment tensors from short-period data observed at regional networks designed typically for monitoring aftershock sequences of large earthquakes. In addition, we test two different inversion approaches-a linear full moment tensor inversion and a nonlinear moment tensor inversion constrained to a shear-tensile source model. The inversions are applied to synthetic first-motion P- and S-wave amplitudes, which mimic seismic observations of aftershocks of the 1999 Mw = 7.4 Izmit earthquake in northwestern Turkey adopting a shear-tensile source model. To analyse the resolution capability for the obtained non-DC components inverted, we contaminate synthetic amplitudes with random noise and incorporate realistic uncertainties in the velocity model as well as in the hypocentre locations. We find that the constrained moment tensor inversion yields significantly smaller errors in the non-DC components than the full moment tensor inversion. In particular, the errors in the compensated linear vector dipole (CLVD) component are reduced if the constrained inversion is applied. Furthermore, we show that including the S-wave amplitudes in addition to P-wave amplitudes into the inversion helps to obtain reliable non-DC components. For the studied station configurations, the resolution remains limited due to the lack of stations with epicentral distances less than 15 km. Assuming realistic noise in waveform data and uncertainties in the velocity model, the errors in the non-DC components are as high as ±15 per cent for the isotropic and CLVD components, respectively, thus being non-negligible in most applications. However, the orientation of P- and T-axes is well determined even when errors in the modelling procedure are high. © The Authors 2014. Published by Oxford University Press on behalf of The Royal Astronomical Society. 2014 English 0956540X 10.1093/gji/ggt502 Geophysical Journal International 196 1869-1877 Helmholtz-Centre, Potsdam German Research Centre for Geosciences (GFZ), Telegrafenberg, D-14473 Potsdam, Germany; Institute of Geophysics, Academy of Sciences of the Czech Republic, Bocni II/1401, Cz-14131 Prague, Czech Republic; Department of Earth Sciences, Free University Berlin, Malteser Strasse 74-100, D-12249 Berlin, Germany 3 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84894083144&doi=10.1093%2fgji%2fggt502&partnerID=40&md5=b9a33e74396b368bade08bede4eff29d cited By 55 E. Stierle V. Vavryčuk J. Šílený M. Bohnhoff article Stierle20141878 We study potential non-double-couple (non-DC) components in aftershocks of the 1999 Izmit earthquake. The Izmit earthquake ruptured a ~140-km-long segment of the North Anatolian Fault Zone in northwestern Turkey and was followed by the Mw = 7.1 Düzce earthquake that extended the rupture further to the east. Focal mechanisms of Izmit aftershocks clearly indicate a segmentation of the rupture into several segments, one of which is the Akyazi Plain, a pull-apart structure, where significant non-DC components might be observed. The analysed earthquake catalogue containswaveforms ofmore than 4000 accurately located events observed at 35 three-component short-period seismic stations. To ensure high-quality datawith good focal coverage, we apply strict quality criteria to the aftershock catalogue reducing the number of events to only 33 aftershocks for which stable moment tensors were calculated using P-and S-wave amplitudes. The moment tensors of the 33 analysed aftershocks display significant differences in the percentage of the non-DC components for the three distinct fault segments: the Izmit-Sapanca, Karadere-Düzce and the Akyazi segments. Events located in the Izmit-Sapanca and Karadere-Düzce segments exhibit only small percentages of the non-DC components and if existent they are mainly positive. This correlates well with the predominant strike-slip stress regime along these segment and also with the main shock rupture being rightlateral strike-slip. In contrary, we found a substantial percentage of non-DC components for events below the Akyazi Plain where the Sapanca Fault splits into the Mudurnu and Karadere faults. There, the observed non-DC components are entirely positive indicating a tensional regime and ranging from 20 to 48 per cent, clearly exceeding the defined error bounds found in a synthetic study. This observation is in accordance with the post-seismic setting following the Izmit main shock that left a remarkable slip deficit of 3.5 m below the Akyazi bend. 2014 English 0956540X 10.1093/gji/ggt503 Geophysical Journal International 196 1878-1888 Potsdam German Research Centre for Geosciences (GFZ), Telegrafenberg, D-14473 Potsdam, Germany; Department of Earth Sciences, Free University Berlin, Malteser Strasse 74-100, D-12249 Berlin, Germany; Institute of Geophysics, Academy of Sciences of the Czech Republic, Boční II/1401, CZ-14131 Prague, Czech Republic 3 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84894091998&doi=10.1093%2fgji%2fggt503&partnerID=40&md5=4f316585dbf98463bfc931260dae643b cited By 43 E. Stierle M. Bohnhoff V. Vavryčuk conference Saeki20143821 The world's first offshore gas production test from methane hydrate deposits was conducted in March 2013, at the test site located on the margin of Daini Atsumi Knoll, off the coasts of Atsumi and Shima peninsulas, in the easten Nankai Trough, of Japan. Approximately 120, 000 cubic meters of methane gas was produced in 6 days using the depressurization technique. The test was a significant advance in Japan's national program to construct the technical base for future commertial methane hydrate resource development. A series of researches for more than 10 years, including two times of onshore production tests in Mallik field and explorations in eastern Nankai Trough, were required to reach the test. This report reviews Japan's research history for methane hydrates. Copyright © 2014, Offshore Technology Conference. 2014 English 9781632665287 01603663 10.4043/25451-ms Proceedings of the Annual Offshore Technology Conference 5 Offshore Technology Conference 3821-3827 Japan Oil, Gas and Metals National Corporation, Japan Hydration; Methane; Offshore oil well production; Offshore technology; Software testing; Testing, Depressurizations; Gas production test; Methane hydrates; Nankai troughs; National program; Production test; Research history; Resource development, Gas hydrates https://www.scopus.com/inward/record.uri?eid=2-s2.0-84944549758&doi=10.4043%2f25451-ms&partnerID=40&md5=4d4afb9284e1c6f91f31001575e3259a cited By 17 T. Saeki article Richard20148132 Creep processes may relax part of the tectonic stresses in active faults, either by continuous or episodic processes. The aim of this study is to obtain a better understanding of these creep mechanisms and the manner in which they change in time and space. Results are presented from microstructural studies of natural samples collected from San Andreas Fault Observatory at Depth borehole drilled through the San Andreas Fault, which reveal the chronology of the deformation within three domain types. (i) A relatively undeformed zone of the host rock reflects the first step of the deformation process with fracturing and grain indentations showing the coupling between fracturing and pressure solution. (ii) Shear deformation development that associates fracturing and solution cleavage processes leads to profound changes in rock composition and behavior with two types of development depending on the ratio between the amount of dissolution and deposition: abundant mineral precipitation strengthens some zones while pervasive dissolution weakens some others, (iii) zones with mainly dissolution trended toward the present-day creeping zones thanks to both the passive concentration of phyllosilicates and their metamorphic transformation into soft minerals such as saponite. This study shows how interactions between brittle and viscous mechanisms lead to widespread transformation of the rocks and how a shear zone may evolve from a zone prone to earthquakes and postseismic creep to a zone of steady state creep. In parallel, the authors discuss how the creeping mechanism, mainly controlled by the very low friction of the saponite in the first 3-4 km depth, may evolve with depth. ©2014. American Geophysical Union. All Rights Reserved. 2014 English 21699313 10.1002/2014JB011489 Journal of Geophysical Research: Solid Earth 119 Blackwell Publishing Ltd 8132-8153 ISTERRE, Université Grenoble Alpes, CNRS, Grenoble, France; Physics of Geological Processes, University of Oslo, Oslo, Norway 11 active fault; brittle deformation; creep; fault zone; metamorphic rock; rock microstructure; San Andreas Fault; tectonic setting; viscosity https://www.scopus.com/inward/record.uri?eid=2-s2.0-84919477317&doi=10.1002%2f2014JB011489&partnerID=40&md5=a5c962ffc25d88341709b731ce64dfaa cited By 31 J. Richard J.-P. Gratier M.-L. Doan A.-M. Boullier F. Renard article 2014 10.16509/j.georeview.2014.01.003 Geological review 60 145-158 1 X. Ding M. Han S. Zhang M. Fu Y. Wan article FRIDLEIFSSON20149 This paper describes the site selection for the IDDP-1 well within the Krafla volcano in 2008. In a feasibility study in 2003, 12 potential well sites within three geothermal areas were suggested and prioritized to meet the goal of finding supercritical temperatures and pressures together with high permeability. In 2006 one of these priority sites was selected within the Krafla field, but in autumn 2007 due to its proximity to the Krafla power plant a new location had to be selected only a few months before drilling. Choice of that new site was justified by new MT-resistivity survey data, seismic data and information from an earlier nearby production well, K-36. 2014 0375-6505 https://doi.org/10.1016/j.geothermics.2013.06.001 Geothermics 49 9-15 IDDP-1 well site at Krafla, Superheated and supercritical reservoir conditions, MT-resistivity data https://www.sciencedirect.com/science/article/pii/S037565051300045X Iceland Deep Drilling Project:The first well, IDDP-1, drilled into Magma G.Ó. Friðleifsson H. Ármannsson Á. Guðmundsson K. Árnason A.K. Mortensen B. Pálsson G.M. Einarsson article Wei20141793 Marine Isotope Stage 11 has been proposed as an analogue for the present interglacial interval; yet, terrestrial climate records from both this region and time interval are rare. The sediments deposited at Lake El'gygytgyn (67°30′N, 172°5′E) in Far East Russia contain a 3·56 Ma record of climate variability. This study presents a high-resolution record of sediment colour change from Marine Isotope Stage 8 to 12 (ca 275 to 475 ka) and demonstrates the link between lake catchment processes and climate variability. The hue colour parameter, calculated from data collected via colour reflectance spectroscopy in the visible spectrum (380 to 720 nm), exhibits correspondence with global climate records. Determining the source of sediment colour changes was achieved through detailed mineralogical and sedimentological methods, and linked to colour changes through a series of colour sensitivity tests. Mineralogical data, measured by X-ray diffraction, reveal fluctuations in concentrations of clay minerals corresponding to colour changes. Further analyses of the clay mineral assemblages show no change in relative clay mineral abundances, yet demonstrate a lake catchment dominated by physical weathering processes. Using measured mineral abundances, reconstructions of sediment colour based on colour reflectance mineral standards link mineral and clay mineral content to overall sediment colour. Colour sensitivity tests demonstrate the ability of iron oxide minerals to stain sediments red. Additionally, colour sensitivity to organic matter content was tested, suggesting that organic content drives variability in the red portion of the spectrum and darkens the overall colour signal. Sediment colour is then ultimately linked to physical weathering of bedrock minerals, with small amounts of chemical weathering producing iron oxides during wet intervals. Fluctuations in the sediment colour reveal a high-resolution record of wet/dry cycles, and provide new information about wet periods for the Russian Arctic region not yet understood from other lake proxy records. © 2014 The Authors. Sedimentology © 2014 International Association of Sedimentologists. 2014 English 00370746 10.1111/sed.12116 Sedimentology 61 Blackwell Publishing Ltd 1793-1811 Climate Systems Research Center and Department of Geosciences, University of Massachusetts Amherst, Amherst, MA 01003, United States; Helmholtz Centre Potsdam, GFZ German Research Centre for Geoscience, Section 5.2, Climate Dynamics and Landscape Evolution, Telegrafenberg, C 321, Potsdam, D-14473, Germany 6 Catchments; Climate change; Color; Digital storage; Erosion; Glacial geology; Iron oxides; Isotopes; Lakes; Oxide minerals; Rare earths; Reflection; Runoff; Sediments; Spectroscopy; Weathering, Chemical weathering; Clay mineral assemblages; Clay mineralogy; High resolution; Marine isotope stages; Organic matter content; Palaeoclimate; Reflectance spectroscopy, Clay minerals https://www.scopus.com/inward/record.uri?eid=2-s2.0-84908501360&doi=10.1111%2fsed.12116&partnerID=40&md5=005988c8fdeeb3ba6a599461388086bb cited By 13 J.H. Wei D.B. Finkelstein J. Brigham-Grette I.S. Castañeda N. Nowaczyk article Stockhecke20141830 The lithostratigraphic framework of Lake Van, eastern Turkey, has been systematically analysed to document the sedimentary evolution and the environmental history of the lake during the past ca 600 000 years. The lithostratigraphy and chemostratigraphy of a 219 m long drill core from Lake Van serve to separate global climate oscillations from local factors caused by tectonic and volcanic activity. An age model was established based on the climatostratigraphic alignment of chemical and lithological signatures, validated by 40Ar/39Ar ages. The drilled sequence consists of ca 76% lacustrine carbonaceous clayey silt, ca 2% fluvial deposits, ca 17% volcaniclastic deposits and 5% gaps. Six lacustrine lithotypes were separated from the fluvial and event deposits, such as volcaniclastics (ca 300 layers) and graded beds (ca 375 layers), and their depositional environments are documented. These lithotypes are: (i) graded beds frequently intercalated with varved clayey silts reflecting rising lake levels during the terminations; (ii) varved clayey silts reflecting strong seasonality and an intralake oxic-anoxic boundary, for example, lake-level highstands during interglacials/interstadials; (iii) CaCO3-rich banded sediments which are representative of a lowering of the oxic-anoxic boundary, for example, lake level decreases during glacial inceptions; (iv) CaCO3-poor banded and mottled clayey silts reflecting an oxic-anoxic boundary close to the sediment-water interface, for example, lake-level lowstands during glacials/stadials; (v) diatomaceous muds were deposited during the early beginning of the lake as a fresh water system; and (vi) fluvial sands and gravels indicating the initial flooding of the lake basin. The recurrence of lithologies (i) to (iv) follows the past five glacial/interglacial cycles. A 20 m thick disturbed unit reflects an interval of major tectonic activity in Lake Van at ca 414 ka bp. Although local environmental processes such as tectonic and volcanic activity influenced sedimentation, the lithostratigraphic pattern and organic matter content clearly reflect past global climate changes, making Lake Van an outstanding terrestrial archive of unprecedented sensitivity for the reconstruction of the regional climate over the last 600 000 years. © 2014 The Authors Sedimentology © 2014 International Association of Sedimentologists. 2014 English 00370746 10.1111/sed.12118 Sedimentology 61 Blackwell Publishing Ltd 1830-1861 Department of Surface Waters Research and Management, Swiss Federal Institute of Aquatic Science and Technology, Eawag, Ueberlandstrasse 133, P.O. Box 611, Dübendorf, 8600, Switzerland; Geological Institute, Swiss Federal Institute of Technology (ETH), Sonneggstrasse 5, Zurich, 8092, Switzerland; GEOMAR Helmholtz Centre for Ocean Research Kiel, Wischhofstr. 1-3, Kiel, 24148, Germany; Swiss Federal Institute of Aquatic Science and Technology, Water Resources and Drinking Water, Eawag, Ueberlandstrasse 133, P. O. Box 611, Dübendorf, 8600, Switzerland; Institute of Biogeochemistry and Pollutant Dynamics, Swiss Federal Institute of Technology (ETH), Universitaetstrasse 16, Zurich, 8092, Switzerland; Institute of Geochemistry and Petrology, Swiss Federal Institute of Technology (ETH), Clausiusstrasse 25, Zurich, 8092, Switzerland; Institute of Geological Sciences and Oeschger Centre for Climate Change Research, University of Bern, Baltzerstrasse 1-3, Bern, 3012, Switzerland 6 Argon; Calcium carbonate; Climate change; Deposits; Environmental protection; Glacial geology; Lakes; Lithology; Oxic sediments; Sedimentology; Silt; Tectonics; Volcanoes, Continental archive; Eastern Anatolia; Glacial/interglacial climate; ICDP project PALEOVAN; Lake sediments; Palaeoenvironmental reconstruction, Anoxic sediments https://www.scopus.com/inward/record.uri?eid=2-s2.0-84907838297&doi=10.1111%2fsed.12118&partnerID=40&md5=9ec0ee07b1b95d9fc173585319b480f0 cited By 80 M. Stockhecke M. Sturm I. Brunner H.-U. Schmincke M. Sumita R. Kipfer D. Cukur O. Kwiecien F.S. Anselmetti article Uddin2014250 The delineation of the Mallik gas hydrate field has utilized extensive well logging and substantial 3D seismic testing and interpretation. This study explores the use of seismic data to quantify the areally heterogeneous gas hydrate distribution. The available Mallik 3D seismic data was compiled and compared/contrasted with available well log data from two adjacent wells. Based on the seismic information, two areally variable (i.e. non-homogeneous) scenarios for gas hydrate distributions are considered: Scenario I having the same initial total hydrate amount as our earlier model areally uniform (homogeneous) distribution, and Scenario II with significantly less overall total hydrate, but honouring the same relative distribution. The scenarios of variable gas hydrate distributions are used in dynamic simulations of the lower Mallik zone. Simulations of each were conducted with and without the role of geomechanics.In Scenario I, we observed multiple gas production peaks (which quite similar to 6 days production behaviour) with higher localized pressure pulses occurred due to strong gas hydrate heterogeneity. In Scenario II, this drastic change in gas production rate was not observed (due to faster pressure evolution in the reservoir). In both Scenarios, the overall reservoir gas production peak is delayed compared to the homogeneous case. This is further delayed by the role of geomechanics. More interestingly, all simulation cases show a very similar overall production trend. This is probably a unique for the Mallik gas hydrate production using single vertical well, including a gas production peak but terminating in a stabilized period of lower but significant gas production.With geomechanics, gas production in general and the gas production peak is shifted and delayed. The geomechanics effect is not purely compaction drive (as in conventional reservoirs, gas production increases with geomechanics). The simulations utilized two set of geomechanical parameters obtained from logs (dynamic parameters) and rocks testing (static parameters). Geomechanical responses based on dynamic parameters were essentially equivalent to simulations ignoring geomechanical effects. The geomechanics simulations indicate an essentially elastic reservoir response (i.e. no plastic failure) assuming a cased vertical well. The Mallik upper zone A and middle zone B are closer to the permafrost and nearer to plasticity limits should be explored. © 2014 . 2014 English 18755100 10.1016/j.jngse.2014.07.002 Journal of Natural Gas Science and Engineering 20 Elsevier B.V. 250-270 Alberta Innovates - Technology Futures, Edmonton, AB T6N 1E4, Canada; Geological Survey of Canada, Natural Resources Canada, Sidney, BC V8L 4B2, Canada; Computer Modeling Group Ltd., Calgary, AB T2L 2A6, Canada Digital storage; Dissociation; Failure (mechanical); Gas industry; Gases; Geomechanics; Geophysical prospecting; Hydration; Seismic response; Seismic waves; Well logging; Well testing, Depressurizations; Dynamic parameters; Gas-hydrate production; Hydrate dissociation; Hydrate distribution; Seismic; Seismic information; Simulation, Gas hydrates https://www.scopus.com/inward/record.uri?eid=2-s2.0-84904871897&doi=10.1016%2fj.jngse.2014.07.002&partnerID=40&md5=9f0f83dec43cbf2c6451a12199a41c02 cited By 10 M. Uddin F. Wright S. Dallimore D. Coombe article Cukur201463 More than 1500km of multi-channel seismic reflection profiles combined with ICDP (International Continental Scientific Drilling Program) drilling data, provide important insights into the stratigraphic evolution of Lake Van, eastern Turkey. Three major basins (Tatvan, Northern and the Deveboynu basins) comprise the main lake basin and are separated by morphological highs (Ahlat ridge and Northern ridge). Moreover, NE-SW faults, parallel to the general tectonic lineament of the area, dominate the entire basin and are in charge of creating graben and half-graben structures. Well-developed prograding deltaic sequences on top of the basement were recognized by seismic stratigraphy analysis. Most likely, they formed during the initial flooding of Lake Van ~600ka. The Tatvan basin sediments are dominated by mass-flow deposits of various origins alternating with undisturbed lacustrine sediments including distinct tephra layers. Faulting along the Tatvan basin margins may have triggered margin-wide slope failures. Ahlat ridge started to form between ca340ka-290ka. Since then, Ahlat ridge was sheltered from major mass-flows due to its elevation. Hence, slow lacustrine sedimentation has prevailed throughout lake history on Ahlat ridge, which was the location of the main drill site during the ICDP. Several lake level fluctuations are evident on the eastern slope area but the deep basins were permanently covered by water. A significant lake-level low stand (ca600kaBP) was found at ~610m below present lake level. The setting of the lake changed at about 30ka. Tectonic activity appears to have waned significantly as the mass-transport deposition decreased across the Tatvan basin while normal undisturbed lacustrine sedimentation prevailed. A different setting is found in the Northern basin from ca90ka to Present, especially due to the strong influx of mostly volcaniclastic turbidites causing sedimentation rates to be about 3.5 times higher (drill Site 1), than at Site 2 (Ahlat ridge). © 2014 Elsevier Ltd. 2014 English 02773791 10.1016/j.quascirev.2014.07.016 Quaternary Science Reviews 104 Elsevier Ltd 63-84 GEOMAR Helmholtz Centre for Ocean Research Kiel, Wischhofstr. 1-3, Kiel, 24148, Germany; Kiel University, Institute of Geosciences, Otto-Hahn-Platz 1, Kiel, 24118, Germany; Istanbul Technical University, EMCOL and Department of Geological Engineering, Maslak, Istanbul, 34469, Turkey; Van Yüzüncü Yil Univ., Department of Geological Engineering, Van, Turkey; Eawag, Swiss Federal Institute of Aquatic Science and Technology, Department of Water Resources and Drinking Water, Überlandstrasse 133, Dübendorf, CH-8600, Switzerland; ETH Zurich, Climate Geology, Sonneggstrasse 5, Zurich, 8092, Switzerland Drills; Faulting; Infill drilling; Mass transfer; Sedimentation; Seismic waves; Seismology; Stratigraphy, Ahlat ridge; Lake vans; Northern basins; Seismic reflections; Tatvan basin, Lakes, delta; drilling; fault; geomorphology; lacustrine deposit; lake evolution; sedimentation; seismic reflection; seismic stratigraphy; turbidity, Lake Van; Turkey https://www.scopus.com/inward/record.uri?eid=2-s2.0-84909636466&doi=10.1016%2fj.quascirev.2014.07.016&partnerID=40&md5=16e7366ec1bbd55cc26c074cb24ff4c5 cited By 27 D. Cukur S. Krastel H.-U. Schmincke M. Sumita M.N. Çağatay A.F. Meydan E. Damci M. Stockhecke article Hillers2014121 Using seismic noise based monitoring techniques we find that seismic velocity variations (dv/v) observed with the borehole array of the Taiwan Chelungpu-fault Drilling Project (TCDP) are controlled by strong precipitation events associated with the Madden-Julian Oscillation (MJO), a dynamic intraseasonal atmospheric pattern in the tropical atmosphere. High-frequency noise (>1 Hz) excited by steady anthropogenic activity in the vicinity of the TCDP allows daily resolution of dv/v time series. Relatively large fluid discharge properties control the equilibration of the ground water table and hence seismic velocities on time scales smaller than the average precipitation recurrence interval. This leads to the observed synchronous 50-80 day periodicity in dv/v and rainfall records in addition to the dominant annual component. Further evidence for the governing role of hydraulic properties is inferred from the similarity of observed dv/v timing, amplitude, and recovery properties with dv/v synthetics generated by a combined model of ground water table changes and diffusive propagation of seismic energy. The lapse time (τ) dependent increase of dv/v amplitudes is controlled by the sensitivity of the diffuse wave field sampled at 1100 m depth to shallower water level fluctuations. The significant vertical offset between stations and water level explains the direct τ dependence which is opposite to the trend previously inferred from measurements at the surface. © 2014 Elsevier B.V. 2014 English 0012821X 10.1016/j.epsl.2014.01.040 Earth and Planetary Science Letters 391 121-127 Institut des Sciences de la Terre, Université Joseph Fourier, CNRS, Grenoble, France; Department of Earth Sciences, National Central University, Jhongli City, Taiwan https://www.scopus.com/inward/record.uri?eid=2-s2.0-84893931995&doi=10.1016%2fj.epsl.2014.01.040&partnerID=40&md5=b1bd39720e14a649b5831cc07bfd0a97 cited By 45 G. Hillers M. Campillo K.-F. Ma article Bräuer20145613 The Vogtland and NW Bohemia region is known for its earthquake swarms; the most intensive swarm since 1985/86 occurred in October 2008. To find further indications for the interaction of ascending mantle-derived fluids and the occurrence of earthquake swarms, detailed fortnightly studies of gas compositions (CO2, N2, Ar, He, H2, and CH 4) and isotope ratios (δ13C, δ15N, and 3He/4He) were carried out between October 2008 and April 2011 at four locations close to the Nový Kostel focal zone and at the Wettinquelle spring (Bad Brambach). From the start of the 2008 earthquake swarm seismically induced isotope-geochemical anomalies were recorded at locations along the Počatky-Plesná fault zone (PPZ) and were, for the first time, also found at degassing locations on the Mariánské LáznÄ• fault zone (MLF). Variations were observed in both the temporal and spatial distributions of the anomalies as well in anomaly strengths, probably due to the positions of these fault zones relative to the focal zone, and to differences in fluid migration pathways. Prior to both the 2000 and 2008 swarms, 3He/4He ratios>6Ra were recorded at the Bublák mofette. These anomalous pre-seismic 3He/ 4He ratios suggest that both the 2000 and 2008 swarms may have been associated with the supply of fresh magma from a less degassed reservoir in the lithospheric mantle. The temporal δ13CCO2 pattern from detailed studies at Bublák between 2005 and 2011 indicates progressive magma degassing, as well as seismically induced variations in the δ13C, providing additional support to the interpretation derived from the 3He/4He ratios. Key Points Isotope anomalies detected in gases from different faults after earthquakes A pre-seismic increase in 3He/4He (> 6 Ra) indicates magma ascent from mantle Isotope monitoring is an excellent way to track active geodynamic processes ©2014. American Geophysical Union. All Rights Reserved. Article 2014 English 21699313 10.1002/2014JB011044 Journal of Geophysical Research: Solid Earth 119 Blackwell Publishing Ltd 5613 – 5632 7 Bohemia; Czech Republic; Germany; Vogtland; carbon dioxide; carbon isotope; degassing; earthquake swarm; earthquake trigger; fault zone; geodynamics; helium isotope; igneous geochemistry; intraplate process; isotopic analysis; isotopic ratio; magmatism; nitrogen isotope; spatial distribution; temporal distribution https://www.scopus.com/inward/record.uri?eid=2-s2.0-84906074681&doi=10.1002%2f2014JB011044&partnerID=40&md5=c17119711e016780b2512a316e76a5a6 Cited by: 27; All Open Access, Green Open Access Karin Bräuer Horst Kämpf Gerhard Strauch article Çağatay201497 Sedimentary, geochemical and mineralogical analyses of the ICDP cores recovered from the Northern Basin (NB) of Lake Van provide evidence of lake level and climatic changes related to orbital and North Atlantic climate system over the last 90ka. High lake levels are generally observed during the interglacial and interstadial periods, which are marked by deposition of varved sediments with high total organic carbon (TOC), total inorganic carbon (TIC), low detrital influx (high Ca/F) and high δ18O and δ13C values of authigenic carbonate. During the glacial and stadial periods of 71-58kaBP (Marine Isotope Stage 4, MIS4) and end of last glaciation-deglaciation (30-14.5kaBP; MIS3) relatively low lake levels prevailed, and grey homogeneous to faintly laminated clayey silts were deposited at high sedimentation and low organic productivity rates.Millennial-scale variability of the proxies during 60-30kaBP (MIS3 is correlated with the Dansgaard-Oeschger (D-O)) and Holocene abrupt climate events in the Atlantic. These events are characterized by laminated sediments, with high TOC, TIC, Ca/Fe, δ18O and δ13C values. The Lake Van NB records correlate well in the region with the climate records from the lakes Zeribar and Urmia in Iran and the Sofular Cave in NW Anatolia, but are in general in anti-phase to those from the Dead Sea Basin (Lake Lisan) in the Levant. The relatively higher δ18O values (0 to-0.4‰) for the interglacial and interstadial periods in the Lake Van NB section are due to the higher temperature and seasonality of precipitation and higher evaporation, whereas the lower values (-0.8 to-2‰) during the glacial and stadial periods are caused mainly by relative decrease in both temperature and seasonality of precipitation. The high δ18O values (up to 4.2‰) during the Younger Dryas, together with the presence of dolomite and low TOC contents, supports evaporative conditions and low lake level. A gradual decrease in the δ18O values from an average of-0.4‰ during the humid early Holocene to an average of-3.5‰ during the more arid late Holocene suggests an increasing contribution of winter precipitation. The changes in the seasonality of precipitation in eastern Anatolia are probably caused by changes in the temperatures of North Atlantic and Mediterranean and in the strength of Siberian High. © 2014 Elsevier Ltd. 2014 English 02773791 10.1016/j.quascirev.2014.09.027 Quaternary Science Reviews 104 Elsevier Ltd 97-116 Istanbul Technical University, Eastern Mediterranean Centre for Oceanography and Limnology (EMCOL), Ayazağa Kampusu, Maslak, Istanbul, 34469, Turkey; Istanbul Technical University, Faculty of Mines, Geological Engineering Department, Turkey; Istanbul Technical University, Eurasia Institute of Earth Sciences, Turkey; Eawag, Swiss Federal Institute of Aquatic Science and Technology, Department of Surface Waters Research and Management, Switzerland; ETH, Geological Institute, Zurich Universitaetsstrasse 5, Zurich, 8092, Switzerland; Firat University, Department of Geological Engineering, Elaziğ, Turkey Climate record; ICDP PaleoVan; Lake levels; Lake vans; Multproxy analyses; Northern basins, authigenesis; climate variation; Dansgaard-Oeschger cycle; Holocene; interstadial; lake level; marine isotope stage; paleoclimate; precipitation (climatology); proxy climate record, Anatolia; Atlantic Ocean; Iran; Kordestan; Lake Urmia; Lake Van; Lake Zeribar; Levant; Mediterranean Region; Turkey https://www.scopus.com/inward/record.uri?eid=2-s2.0-84909599486&doi=10.1016%2fj.quascirev.2014.09.027&partnerID=40&md5=45d48abb11b99b381346a3ee8fb940b6 cited By 73 M.N. Çağatay N. Öğretmen E. Damci M. Stockhecke Ü. Sancar K.K. Eriş S. Özeren article Sandig20141421 Our study at this natural analog site contributes to the evaluation of methods within a hierarchical monitoring concept suited for the control of CO2 degassing. It supports the development of an effective monitoring concept for geological CO2 storage sites-carbon capture and storage as one of the pillars of the European climate change efforts. This study presents results of comprehensive investigations along a 500-m long profile within the Hartoušov (Czech Republic) natural CO2 degassing site and gives structural information about the subsurface and interaction processes in relation to parameters measured. Measurements of CO2 concentrations and investigation of the subsurface using electrical resistivity tomography and self-potential methods provide information about subsurface properties. For their successful application it is necessary to take seasonal variations (e.g., soil moisture, temperature, meteorological conditions) into consideration due to their influence on these parameters. Locations of high CO2 concentration in shallow depths are related to positive self-potential anomalies, low soil moistures and high resistivity distributions, as well as high δ13C values and increased radon concentrations. CO2 ascends from deep geological sources via preferential pathways and accumulates in coarser sediments. Repetition of measurements (which includes the effects of seasonal variations) revealed similar trends and allows us to identify a clear, prominent zone of anomalous values. Coarser unconsolidated sedimentary layers are beneficial for the accumulation of CO2 gas. The distribution of such shallow geological structures needs to be considered as a significant environmental risk potential whenever sudden degassing of large gas volumes occurs. © 2014 Springer-Verlag Berlin Heidelberg. Article 2014 English 18666280 10.1007/s12665-014-3242-5 Environmental Earth Sciences 72 Springer Verlag 1421 – 1434 5 Czech Republic; Carbon; Carbon capture; Climate change; Degassing; Electric conductivity; Geology; Moisture; Risk assessment; Soil moisture; Soils; Electrical resistivity tomography; Evaluation of methods; Meteorological condition; Permeable structures; Preferential pathways; Self potential; Self-potential anomalies; Structural information; carbon dioxide; carbon sequestration; climate change; comparative study; degassing; electrical resistivity; leakage; permeability; radon; risk assessment; underground storage; Carbon dioxide https://www.scopus.com/inward/record.uri?eid=2-s2.0-84901574265&doi=10.1007%2fs12665-014-3242-5&partnerID=40&md5=9d467d658530b16dc8297e3ff0562231 Cited by: 12 Claudia Sandig Uta Sauer Karin Bräuer Ulrich Serfling Claudia Schütze article Elders201435 Scientists, engineers, and policy makers gathered at a workshop in the San Bernardino Mountains of southern California in October 2013 to discuss the science and technology involved in developing high-enthalpy geothermal fields. A typical high-enthalpy geothermal well between 2000 and 3000m deep produces a mixture of hot water and steam at 200-300 °C that can be used to generate about 5-10MWe of electric power. The theme of the workshop was to explore the feasibility and economic potential of increasing the power output of geothermal wells by an order of magnitude by drilling deeper to reach much higher pressures and temperatures. Development of higher enthalpy geothermal systems for power production has obvious advantages; specifically higher temperatures yield higher power outputs per well so that fewer wells are needed, leading to smaller environmental footprints for a given size of power plant. Plans for resource assessment and drilling in such higher enthalpy areas are already underway in Iceland, New Zealand, and Japan. There is considerable potential for similar developments in other countries that already have a large production of electricity from geothermal steam, such as Mexico, the Philippines, Indonesia, Italy, and the USA. However drilling deeper involves technical and economic challenges. One approach to mitigating the cost issue is to form a consortium of industry, government and academia to share the costs and broaden the scope of investigation. An excellent example of such collaboration is the Iceland Deep Drilling Project (IDDP), which is investigating the economic feasibility of producing electricity from supercritical geothermal reservoirs, and this approach could serve as model for future developments elsewhere. A planning committee was formed to explore creating a similar initiative in the USA. 2014 English 18168957 10.5194/sd-18-35-2014 Scientific Drilling 18 Copernicus GmbH 35-42 Dept. of Earth Sciences, University of California, Riverside, CA 92521, United States; DOSECC Exploration Sciences, 2075 S. Pioneer Rd., Salt Lake City, UT 84104, United States; Dept. of Geology, University of California Davis, 1 Shields Avenue, Davis, CA 95616, United States; CalEnergy Operating Corp, 7030 Gentry Road, Calipatria, CA 92233, United States Electric power generation; Enthalpy; Geothermal energy; Geothermal wells; Well drilling, Economic challenges; Economic feasibilities; Environmental footprints; Geothermal reservoir; Iceland deep drilling projects; Resource assessments; Science and Technology; Southern California, Geothermal fields https://www.scopus.com/inward/record.uri?eid=2-s2.0-84926287342&doi=10.5194%2fsd-18-35-2014&partnerID=40&md5=f045a3ac57e3c14fb118c1ba1a531d46 cited By 4 W.A. Elders D. Nielson P. Schiffman Jr. Schriener article Popov2014896 We reanalyzed and compared unique data sets, which we obtained in the frame of combined petrophysical and geothermal investigations within scientific drilling projects on four impact structures: the Puchezh-Katunki impact structure (Vorotilovo borehole, Russia), the Ries impact structure (Noerdlingen-73 borehole, Germany), the Chicxulub impact structure (ICDP Yaxcopoil-1 borehole, Mexico), and the Chesapeake impact structure (ICDP-USGS-Eyreville borehole, USA). For a joined interpretation, we used the following previously published data: thermal properties, using the optical scanning technique, and porosities, both measured on densely sampled halfcores of the boreholes. For the two ICDP boreholes, we also used our previously published P-wave velocities measured on a subset of cores. We show that thermal conductivity, thermal anisotropy, porosity, and velocity can be correlated with shock metamorphism (target rocks of the Puchezh-Katunki and Ries impact structures), and confirm the absence of shock metamorphism in the samples taken from megablocks (Chicxulub and Chesapeake impact structure). The physical properties of the lithic impact breccias and suevites are influenced mainly by their impact-related porosity. Physical properties of lower porosity lithic impact breccias and suevites are also influenced by their chemical composition. These data allow for a distinction between different types of breccias due to differences concerning the texture and chemistry and the different amounts of melt and rock clasts. © The Meteoritical Society, 2014. Article 2014 English 10869379 10.1111/maps.12299 Meteoritics and Planetary Science 49 University of Arkansas 896 – 920 5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84900812435&doi=10.1111%2fmaps.12299&partnerID=40&md5=d9e395827c80b7e60ffcf7484bbd0884 Cited by: 5 Y. Popov S. Mayr R. Romushkevich H. Burkhardt H. Wilhelm article Kuzmin20141 Earlier reconstructions of climatic and environmental changes from data of deep-water drilling on the Akademichesky Ridge in Lake Baikal were based both on the content of biogenic silica or the abundance of diatom valves and on the results of X-ray diffraction (XRD) analysis of the sediment mineralogy. It was established that clay minerals are the main carrier of information about climatic variations in a drainage basin. The content of biogenic silica strictly correlates with two chrystallochemical parameters: the abundance of smectite beds in illite-smectite and the abundance of illite. However, detailed analysis of clay minerals calls for exclusive XRD techniques without mass determination of minerals in the sediments of long Baikal cores. We propose a new approach to determine the mineral composition of bottom sediments, based on their chemical composition. We compared the average chemical compositions of Pleistocene, Pliocene, and Miocene core sediments from the boreholes BDP-96 and BDP-98 and sediments of the Paleo-Barguzin River avandelta and recognized groups of chemical elements marking warm and cold climatic periods. However, the difference in the chemical compositions of sediments in warm and cold periods is insignificant. Since an XRD analysis of mineral composition is usually performed for short time intervals, it was necessary to identify cold and warm intervals by the mineral composition calculated from the chemical composition of sediments. The mineral contents were estimated using the Selektor software. Based on the average contents of chemical elements, we computed the mineral composition of the bottom sediments throughout the BDP-98 section and studied its warm and cold periods. We have established that feldspars weakly respond to climatic changes, their contents show minor variations in warm and cold epochs, whereas the contents of mica minerals change seriously. Thus, clay minerals, together with biogenic silica, are a good indicator of paleoclimatic environmental changes. © 2014 V.S. Sobolev IGM, Siberian Branch of the RAS. Article 2014 English 10687971 10.1016/j.rgg.2013.12.001 Russian Geology and Geophysics 55 1 – 17 1 Akademichesky Ridge; Barguzin River; Buryatia; Lake Baikal; Russian Federation; Bacillariophyta; borehole; chemical composition; clay mineral; climate variation; deep water; drainage basin; environmental change; environmental indicator; Miocene; Pleistocene; Pliocene; reconstruction; sediment chemistry; silica; stratigraphic correlation https://www.scopus.com/inward/record.uri?eid=2-s2.0-84893019865&doi=10.1016%2fj.rgg.2013.12.001&partnerID=40&md5=a5726c95f4be1b901391ad71015651a2 Cited by: 12 M.I. Kuz'min V.A. Bychinskii E.V. Kerber A.V. Oshchepkova A.V. Goreglyad E.V. Ivanov article Qu2014234 The chronostratigraphy, sequence and distribution of Huoshiling Formation (H-Form) in the Songliao Basin are discussed and summarized on the basis of biostratigraphy, isotopic dating, lithostratigraphy as well as magnetostratigraphy. The H-Form is the first rifting basin stage with the filling sequence of mainly volcanic rocks in northeastern China and adjacent areas. Laterally, it is characterized by the widespread distribution, remarkable variation in volcanic eruption time and scale between fault depressions. The H-Form yielded plant megafossils in a wide range of periods. The sporo-pollen assemblages show a blooming age of the early Cretaceous. Characteristic megaspore fossil and magnetostratigraphy indicate the age of the Jurassic. Overlying sequence of the H-Form is also concerned in order to constrain its time span. The bottom of Yingcheng Formation is 130 Ma, the duration of Shahezi Formation is about 10 Ma, so that the top age of the H-Form should be ca. 140 Ma. The minimum duration of H-Form is calculated ca. 8 Ma, and its bottom age ought to approach about 150 Ma. The isotopic age dating on the volcanic rocks of H-Form mainly ranges from 140 Ma to 150 Ma. All these evidences above suggest that the age of H-Form can be well constrained from the Tithonian to the Berriasian or to the bottom of the Valanginian. The Jurassic-Cretaceous boundary(J/K boundary) in the Songliao Basin probably exists inside the Huoshiling Formation. 2014 Chinese 10052321 10.13745/j.esf.2014.02.017 Earth Science Frontiers 21 Science Frontiers editorial department 234-250 College of Earth Science, Jilin University, Changchun 130061, China; Research Center of Paleontology and Stratigraphy, Jilin University, Changchun 130026, China; State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing 100083, China 2 Isotopes; Volcanic rocks, Chronostratigraphy; Huoshiling Formation; Jurassic-Cretaceous; Jurassic-Cretaceous boundary; Magnetostratigraphy; Shahezi formations; Songliao basin; Volcanic eruptions, Plants (botany) https://www.scopus.com/inward/record.uri?eid=2-s2.0-84898649437&doi=10.13745%2fj.esf.2014.02.017&partnerID=40&md5=1110ae4e953d947dfb714e635c8374cd cited By 19 X. Qu P. Wang Y. Gao X. Wan article Stockhecke20148 Lake Van sediment cores from the Ahlat Ridge and Northern Basin drill sites of the ICDP project PALEOVAN contain a wealth of information about past environmental processes. The sedimentary sequence was dated using climatostratigraphic alignment, varve chronology, tephrostratigraphy, argon-argon single-crystal dating, radiocarbon dating, magnetostratigraphy, and cosmogenic nuclides. Based on the lithostratigraphic framework, the different age constraints are compiled and a robust and precise chronology of the 600,000 year-old Lake Van record is constructed. Proxy records of total organic carbon content and sediment color, together with the calcium/potassium-ratios and arboreal pollen percentages of the 166-m-long event-corrected Ahlat Ridge record, mimic the Greenland isotope stratotype (NGRIP). Therefore, the proxy records are systematically aligned to the onsets of interstadials reflected in the NGRIP and synthesized Greenland ice-core stratigraphy. The chronology is constructed using 49 age control points derived from visual synchronization with the Greenland ice-core stratigraphy using the GICC05 timescale, an absolutely-dated speleothem timescale (e.g., Hulu, Sanbao, Linzhu cave) and the Epica Dome C timescale. In addition, the uppermost part of the sequence is complemented with four ages from Holocene varve chronology and three calibrated radiocarbon ages. Furthermore, nine argon-argon ages and a comparison of the relative paleointensity record of the magnetic field with reference curve PISO-1500 confirm the accuracy of the age model. Also the identification of the Laschamp event via measurements of 10Be in the sediment confirms the presented age model. The chronology of the Ahlat Ridge record is transferred to the 79-m-long event-corrected composite record from the Northern Basin and supplemented by additional radiocarbon dating on organic marco-remains. The basal age of the Northern Basin record is estimated at ~90ka. The variations of the time series of total organic carbon content, the Ca/K ratio, and the arboreal pollen percentages illustrate that the presented chronology links ice-marine-terrestrial stratigraphies and that the paleoclimate data are suited for reconstructions and modeling of the Quaternary and Pleistocene climate evolution in the Near East at millennial timescales. Furthermore, the chronology of the last 250ka can be used to test other dating techniques. © 2014 Elsevier Ltd. 2014 English 02773791 10.1016/j.quascirev.2014.04.008 Quaternary Science Reviews 104 Elsevier Ltd 8-17 Eawag, Swiss Federal Institute of Aquatic Science and Technology, Department of Surface Waters Research and Management, Ueberlandstrasse 133, P.O.Box 611, Dübendorf, 8600, Switzerland; ETH, Geological Institute, Zurich Universitaetsstrasse 5, Zurich, 8092, Switzerland; Ruhr-University Bochum, Universitaetstrasse 150, Bochum, 44801, Germany; Istituto di Scienze Marine, ISMAR-CNR, Bologna, Italy; Institute of Geological Sciences and Oeschger Centre for Climate Change Research, University of Bern, Baltzerstrasse 1-3, Bern, 3012, Switzerland; Department of Geological Engineering, Eastern Mediterranean Centre for Oceanography and Limnology, Istanbul Technical University, Maslak, Istanbul, 34469, Turkey; Department of Geological Sciences, University of Florida, Gainesville, FL 32611, United States; Swiss Federal Institute of Aquatic Science and Technology, Water Resources and Drinking Water, Eawag, Ueberlandstrasse 133, P. O. Box 611, D€ubendorf, 8600, Switzerland; Institute of Biogeochemistry and Pollutant Dynamics, Swiss Federal Institute of Technology (ETH), Universitaetstrasse 16, Zurich, 8092, Switzerland; Institute of Geochemistry and Petrology, Swiss Federal Institute of Technology (ETH), Clausiusstrasse 25, Zurich, 8092, Switzerland; Steinmann Institute of Geology, Mineralogy and Paleontology, Bonn University, Nussallee 8, Bonn, 53115, Germany Argon; Glacial geology; Ice control; Isotopes; Lakes; Organic carbon; Sediments; Single crystals; Stratigraphy, ICDP project PALEOVAN; Long terrestrial paleoenvironmental records; Magnetostratigraphy; Radiometric dating; Tephrostratigraphy, Ice, argon-argon dating; chronostratigraphy; lithostratigraphy; magnetostratigraphy; NorthGRIP; paleoclimate; Quaternary; radiometric method; sediment core; sediment property; sedimentary sequence; tephrochronology; total organic carbon, Lake Van; Turkey https://www.scopus.com/inward/record.uri?eid=2-s2.0-84909639499&doi=10.1016%2fj.quascirev.2014.04.008&partnerID=40&md5=298981880bee7258373606b9ab54c676 cited By 71 M. Stockhecke O. Kwiecien L. Vigliotti F.S. Anselmetti J. Beer M.N. Çağatay J.E.T. Channell R. Kipfer J. Lachner T. Litt N. Pickarski M. Sturm article Zeng20141846 Located at the northeastern margin of the Qinghai-Tibet Plateau (QTP) in the Asian interior, the Lake Qinghai is sensitive to environmental change and thus an outstanding site for studying paleoenvironmental changes. Thick deposits in the Lake Qinghai provide important geological archives for obtaining high-resolution records of continental environmental history. The longest drilling core obtained from the Lake Qinghai, named Erlangjian (ELJ), reached about 1109 m and was investigated to determine its clay mineral assemblage and grain size distributions. Clay mineralogical proxies, including type, composition, and their ratios, as well as the illite crystallinity (KI) and chemical index (CI), in combination with grain size data, were used for reconstructing the history of paleoenvironmental evolution since the late Miocene in the Lake Qinghai Basin. The clay mineral records indicate that the clay mainly comprise detritus originating from peripheral material and has experienced little or no diagenesis. The proportion of authigenic origin was minor. Illite was the most abundant clay mineral, followed by chlorite, kaolinite, and smectite. Variations of clay mineral indexes reflect the cooling and drying trends in the Lake Qinghai region, and the grain size distribution is coincided with the clay minerals indexes. The paleoclimatic evolution of the Lake Qinghai Basin since the late Miocene can be divided into five intervals. The climate was relatively warm and wet in the early of late Miocene, then long-term trends in climate change character display cooling and drying; later in the late Miocene until early Pliocene the climate was in a short relatively warm and humid period; since then the climate was relatively colder and drier. These results also suggest multiple tectonic uplift events in the northeastern QTP. © 2014 Science China Press and Springer-Verlag Berlin Heidelberg. Article 2014 English 16747313 10.1007/s11430-013-4817-9 Science China Earth Sciences 57 Science in China Press 1846 – 1859 8 China; Qinghai; Qinghai Lake; Qinghai-Xizang Plateau; Clay minerals; Climate change; Grain size and shape; Kaolinite; Tectonics; Clay mineral assemblages; Grain size distribution; Lake Qinghai; Paleoclimates; Paleoenvironmental change; Qinghai Tibet plateau; Tectonic uplift; Weathering conditions; clay mineral; grain size; Miocene; paleoclimate; paleoenvironment; proxy climate record; sediment core; uplift; weathering; Lakes https://www.scopus.com/inward/record.uri?eid=2-s2.0-84905008706&doi=10.1007%2fs11430-013-4817-9&partnerID=40&md5=6c0847132282106e1976de8b7a1e0a3d Cited by: 20 MengXiu Zeng YouGui Song ZhiSheng An Hong Chang Yue Li article Panagiotopoulos2014643 The transboundary Lake Prespa (Albania/former Yugoslav Republic of Macedonia/Greece) has been recognized as a conservation priority wetland. The high biodiversity encountered in the catchment at present points to the refugial character of this mountainous region in the southwestern Balkans. A lake sediment core retrieved from a coring location in the northern part of the lake was investigated through sedimentological, geochemical, and palynological analyses. Based on tephrochronology, radiocarbon and electron spin resonance (ESR) dating, and cross correlation with other Northern Hemisphere records, the age model suggests that the basal part of core Co1215 reaches back to 92 ka cal BP. Here we present the responses of this mid-altitude site (849 m a.s.l.) to climate oscillations during this interval and assess its sensitivity to millennial-scale variability. Endogenic calcite precipitation occurred in marine isotope stages (MIS) 5 and 1 and is synchronous with periods of increased primary production (terrestrial and/or lacustrine). Periods of pronounced phytoplankton blooms (inferred from green algae and dinoflagellate concentrations) are recorded in MIS 5 and MIS 1 and suggest that the trophic state and lake levels underwent substantial fluctuations. Three major phases of vegetation development are distinguished: the forested phases of MIS 5 and MIS 1 dominated by deciduous trees with higher temperatures and moisture availability, the open landscapes of MIS 3 with significant presence of temperate trees, and the pine-dominated open landscapes of MIS 4 and MIS 2 with lower temperatures and moisture availability. Our findings suggest significant changes in forest cover and landscape openness, as well as in the properties of the vegetation belts (composition and distribution) over the period examined. The study area most likely formed the upper limit of several drought-sensitive trees (temperate tree refugium) at these latitudes in the Mediterranean mountains. © Author(s) 2014. Article 2014 English 18149324 10.5194/cp-10-643-2014 Climate of the Past 10 European Geosciences Union 643 – 660 2 Balkan; Turkmenistan; algal bloom; climate variation; electron spin resonance dating; mountain region; Northern Hemisphere; paleoclimate; palynology; phytoplankton; primary production; radiocarbon dating; sediment core; tephrochronology; transboundary cooperation https://www.scopus.com/inward/record.uri?eid=2-s2.0-84897423832&doi=10.5194%2fcp-10-643-2014&partnerID=40&md5=18afe0e8d30f5c2c1f55205e66874963 Cited by: 53; All Open Access, Gold Open Access, Green Open Access K. Panagiotopoulos A. Böhm M.J. Leng B. Wagner F. Schäbitz article Moore201482 Creep in the San Andreas Fault Observatory at Depth (SAFOD) drillhole is localized to two foliated gouges, the central deforming zone (CDZ) and southwest deforming zone (SDZ). The gouges consist of porphyroclasts of serpentinite and sedimentary rock dispersed in a foliated matrix of Mg-smectite clays that formed as a result of shearing-enhanced reactions between the serpentinite and quartzofeldspathic rocks. The CDZ takes up most of the creep and exhibits differences in mineralogy and texture from the SDZ that are attributable to its higher shearing rate. In addition, a ~0.2-m-wide sector of the CDZ at its northeastern margin (NE-CDZ) is identical to the SDZ and may represent a gradient in creep rate across the CDZ. The SDZ and NE-CDZ have lower clay contents and larger porphyroclasts than most of the CDZ, and they contain veinlets and strain fringes of calcite in the gouge matrix not seen elsewhere in the CDZ. Matrix clays in the SDZ and NE-CDZ are saponite and corrensite, whereas the rest of the CDZ lacks corrensite. Saponite is younger than corrensite, reflecting clay crystallization under declining temperatures, and clays in the more actively deforming portions of the CDZ have better equilibrated to the lower-temperature conditions. © 2014. 2014 English 01918141 10.1016/j.jsg.2014.09.002 Journal of Structural Geology 68 Elsevier Ltd 82-96 U. S. Geological Survey, 345 Middlefield Road MS/977, Menlo Park, CA 94025, United States PA Corrensite; Fault gouge; SAFOD; San Andreas fault; Saponite; Shearing-enhanced reactions, corrensite; creep; damage; deformation; fault gouge; mineralogy; San Andreas Fault; saponite; sedimentary rock; serpentinite; shear zone; texture https://www.scopus.com/inward/record.uri?eid=2-s2.0-84907863573&doi=10.1016%2fj.jsg.2014.09.002&partnerID=40&md5=b98e68ae3c728aa7f1132446d9f5d20a cited By 19 D.E. Moore article Popov2014896 We reanalyzed and compared unique data sets, which we obtained in the frame of combined petrophysical and geothermal investigations within scientific drilling projects on four impact structures: the Puchezh-Katunki impact structure (Vorotilovo borehole, Russia), the Ries impact structure (Noerdlingen-73 borehole, Germany), the Chicxulub impact structure (ICDP Yaxcopoil-1 borehole, Mexico), and the Chesapeake impact structure (ICDP-USGS-Eyreville borehole, USA). For a joined interpretation, we used the following previously published data: thermal properties, using the optical scanning technique, and porosities, both measured on densely sampled halfcores of the boreholes. For the two ICDP boreholes, we also used our previously published P-wave velocities measured on a subset of cores. We show that thermal conductivity, thermal anisotropy, porosity, and velocity can be correlated with shock metamorphism (target rocks of the Puchezh-Katunki and Ries impact structures), and confirm the absence of shock metamorphism in the samples taken from megablocks (Chicxulub and Chesapeake impact structure). The physical properties of the lithic impact breccias and suevites are influenced mainly by their impact-related porosity. Physical properties of lower porosity lithic impact breccias and suevites are also influenced by their chemical composition. These data allow for a distinction between different types of breccias due to differences concerning the texture and chemistry and the different amounts of melt and rock clasts. © The Meteoritical Society, 2014. 2014 10.1111/maps.12299 Meteoritics and Planetary Science 49 896-920 Schlumberger Moscow Research Centre, Moscow, Russian Federation; Department Section Geophysics, Freie Universität Berlin, Berlin, Germany; Department of Applied Geosciences, Technische Universität Berlin, Berlin, Germany; Geophysical Institute, Karlsruhe Institute of Technology, Karlsruhe, Germany 5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84900812435&doi=10.1111%2fmaps.12299&partnerID=40&md5=d9e395827c80b7e60ffcf7484bbd0884 cited By 5 Y. Popov S. Mayr R. Romushkevich H. Burkhardt H. Wilhelm article Carlino20141 Article 2014 10.1007/s00445-014-0870-2 Bulletin of Volcanology 76 1 – 7 10 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84928900065&doi=10.1007%2fs00445-014-0870-2&partnerID=40&md5=72dff8cde8d1e61afa01c0a172ba3ea6 Cited by: 9 Stefano Carlino Anna Tramelli Renato Somma article Riedel2014292 Shear wave velocity data have been acquired at several marine gas hydrate drilling expeditions, including the India National Gas Hydrate Program Expedition 1 (NGHP-01), the Ocean Drilling Program (ODP) Leg 204, and Integrated Ocean Drilling Program (IODP) Expedition 311 (X311). In this study we use data from these marine drilling expeditions to develop an understanding of general grain-size control on the P- and S-wave properties of sediments. A clear difference in the downhole trends of P-wave (Vp) and S-wave (Vs) velocity and the Vp/Vs ratio from all three marine regions was observed: the northern Cascadia margin (IODP X311) shows the highest P-wave and S-wave velocity values overall and those from the India margin (Expedition NGHP-01) are the lowest. The southern Cascadia margin (ODP Leg 204) appears to have similar low P-wave and S-wave velocity values as seen off India. S-wave velocity values increase relative to the sites off India, but they are not as high as those seen on the northern Cascadia margin. Such regional differences can be explained by the amount of silt/sand (or lack thereof) occurring at these sites, with northern Cascadia being the region of the highest silt/sand occurrences. This grain-size control on P-wave and S-wave velocity and associated mineral composition differences is amplified when compared to the Arctic permafrost environments, where gas hydrate predominantly occurs in sand- and silt-dominated formations. Using a cross-plot of gamma ray values versus the Vp/Vs ratio, we compare the marine gas hydrate occurrences in these regions: offshore eastern India margin, offshore Cascadia margin, the Ignik-Sikumi site in Alaska, and the Mallik 5L-38 site in the Mackenzie Delta. The log-data from the Arctic permafrost regions show a strongly linear Vp-Vs relationship, similar to the previously defined empirical relationships by Greenberg and Castagna (1992). P- and S-wave velocity data from the India margin and ODP Leg 204 deviate strongly from these linear trends, whereas data from IODP X311 plot closer to the trend of the Arctic data sets and previously published relationships. Three new linear relationships for different grain size marine sediment hosts are suggested:. a)mud-dominated (Mahanadi Basin, ODP Leg 204 & NGHP-01-17): Vs=1.5854×Vp-2.1649b)silty-mud (KG Basin): Vs=0.8105×Vp-1.0223c)silty-sand (IODP X311): Vs=0.5316×Vp-0.4916We investigate the relationship of gas hydrate saturation determined from electrical resistivity on the Vp/Vs ratio and found that the sand-dominated Arctic hosts show a clearly decreasing trend of Vp/Vs ratio with gas hydrate saturation. Though limited due to lower overall GH saturations, a similar trend is seen for sites from IODP X311 and at the ash-dominated NGHP-01-17 sediment in the Andaman Sea. Gas hydrate that occurs predominantly in fractured clay hosts show a different trend where the Vp/Vs ratio is much higher than at sand-dominated sites and remains constant or increases slightly with increasing gas hydrate saturation. This trend may be the result of anisotropy in fracture-dominated systems, where P- and S-wave velocities appear higher and Archie-based saturations of gas hydrate are overestimated. Gas hydrate concentrations were also estimated in these three marine settings and at Arctic sites using an effective medium model, combining P- and S-wave velocities as equally weighted constraints on the calculation. The effective medium approach generally overestimates S-wave velocity in high-porosity, clay-dominated sediments, but can be accurately used in sand-rich formations. © 2014. 2014 English 02648172 10.1016/j.marpetgeo.2014.07.028 Marine and Petroleum Geology 58 Elsevier Ltd 292-320 Natural Resources Canada, Geological Survey of Canada - Pacific, 9860 West Saanich Road, Sidney, BC V8L4B2, Canada; Borehole Research Group, Lamont-Doherty Earth Observatory of Columbia University, Palisades, NY 10964, United States PA https://www.scopus.com/inward/record.uri?eid=2-s2.0-85027932674&doi=10.1016%2fj.marpetgeo.2014.07.028&partnerID=40&md5=bdd7df78039250edde67c9a5879e144f cited By 20 M. Riedel D. Goldberg G. Guerin article Acarel20144519 Monitoring coseismic velocity changes is a major challenge, since the Earth crust has to be uniformly sampled at preseismic, coseismic, and postseismic stages using repeating active or natural sources. Here we investigate the crustal response to the 2011 Van/Turkey earthquake using ambient noise, which provides the best possible temporal resolution. Combined recordings from the nearest five broadband stations are analyzed for a time period of 6 months framing the main shock. We observe a coseismic velocity decrease of up to 0.76% in the vicinity of the main shock in the frequency range of 0.05-0.3 Hz. The velocity drop is largest at close proximity to the earthquake hypocenter and decreases systematically with distance. We also find a correlation between coseismic velocity decrease and the amount of coseismic slip on the rupture plane. The observed velocity drop shows the drastic response of the brittle crust in response to a major earthquake. Key Points A coseismic velocity change The 2011 Van earthquake Scaling between the velocity change and slip ©2014. American Geophysical Union. All Rights Reserved. 2014 English 00948276 10.1002/2014GL060624 Geophysical Research Letters 41 Blackwell Publishing Ltd 4519-4526 GFZ German Research Centre for Geosciences, Potsdam, Germany; Institute of Geological Sciences, Free University Berlin, Berlin, Germany; Earthquake Department, Turkish Republic Disaster and Emergency Management Presidency, Ankara, Turkey 13 Acoustic noise; Drops; Earthquakes; Structural geology, 2011 Van earthquake/Turkey; Ambient noise; Broadband station; Close proximity; Coseismic slips; Frequency ranges; Temporal resolution; Velocity changes, Velocity https://www.scopus.com/inward/record.uri?eid=2-s2.0-84903861810&doi=10.1002%2f2014GL060624&partnerID=40&md5=df46322bafcb2f0d7f2624f93651eb67 cited By 10 D. Acarel F. Bulut M. Bohnhoff R. Kartal article Wu201482 The Songke-1 north (SK-1n) borehole recovered a continuous, 1541.66 m Late Santonian-Early Danian terrestrial succession in Songliao Basin (SB), northeastern China. It provides a unique record for improving our understanding of continental paleoclimate and ecological system in Cretaceous greenhouse world. Here we use thorium (Th) logging data as a paleoenvironmental and paleoclimatic proxy to conduct a detailed cyclostratigraphic study on the SK-1n core. Power spectra, evolutionary fast Fourier transformation and wavelet analysis all reveal significant decameter- to meter-scale sedimentary cycles in the Nenjiang (K2n), Sifangtai (K2s) and Mingshui (K2m) formations. The ratios of cycle wavelengths in these stratigraphic units are ~20:5:2:1, and are interpreted as Milankovitch cycles of 405 kyr and 100 kyr eccentricity, 38.4 kyr obliquity and 20 kyr precession cycles, respectively. An astronomical time scale (ATS) is established by tuning filtered 405 kyr eccentricity cycles to a target curve of the astronomical solution La2010d based on the magnetostratigraphic time framework of the SK-1n borehole. This ATS provides precise numerical ages for stratigraphic boundaries, biozones, geological and geophysical events, and serves as a basis for correlation of strata and events between marine and terrestrial systems. The Cretaceous/Paleogene (K/Pg), Campanian/Maastrichtian, Santonian/Campanian boundaries are estimated at core depths of 318 m, 752.8 m and 1751.1 m, respectively. A ~3.8 myr-long hiatus between the Nenjiang (K2n) and Sifangtai (K2s) formations occurs from 76.1 to 79.9 million years ago. The ages and durations of magnetochrons C33r to C30n are precisely estimated and provide new constraints on the Late Cretaceous Geomagnetic Polarity Time Scale (GPTS) and South Atlantic sea-floor spreading rates. © 2014 Elsevier B.V. 2014 English 0012821X 10.1016/j.epsl.2014.09.038 Earth and Planetary Science Letters 407 Elsevier 82-95 State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences (Beijing), Beijing, 100083, China; School of Ocean Sciences, China University of Geosciences (Beijing), Beijing, 100083, China; Department of Earth and Planetary Sciences, Johns Hopkins University, Baltimore, MD 21218, United States; Department of Geoscience, University of Nevada, Las Vegas, NV 89154, United States Astronomical time scale (ATS); Continental environments; Cyclostratigraphy; Late cretaceous; Songliao basin, borehole; cyclostratigraphy; Danian; eccentricity; geological record; magnetostratigraphy; paleoclimate; paleoecology; paleoenvironment; proxy climate record; Santonian; seafloor spreading; stratigraphic boundary; thorium; timescale, Atlantic Ocean; Atlantic Ocean (South); China; Songliao Basin https://www.scopus.com/inward/record.uri?eid=2-s2.0-84907994161&doi=10.1016%2fj.epsl.2014.09.038&partnerID=40&md5=784b34ae200fe2134deb8c6a7a9246c1 cited By 95 H. Wu S. Zhang L.A. Hinnov G. Jiang T. Yang H. Li X. Wan C. Wang article gartner2014dating 2014 Precambrian Research 246 Elsevier 281--295 Claudia Gärtner Heinrich Bahlburg Victor A Melezhik Jasper Berndt conference McLing2014143 In the coming summer (Summer 2014), we will have another sampling campaign. The composition of waters presented in Table 1 as well as compositions of waters yet to be collected will be used for temperature estimates with MEG and traditional geothermometers. In addition to the geothermometry, different mixing models will be applied to delineate areas with high potential for geothermal resources in the ESRP. As the project progresses, more detailed reports will be presented/published in appropriate venues. Copyright © (2014) by the Geothermal Resources Council All right reserved. 2014 English 9781634394673 01935933 Transactions - Geothermal Resources Council 38 Geothermal Resources Council 143-153 Idaho National Laboratory, United States; Idaho State University, United States; University of Idaho, United States; Ldaho Geological Survey, United States; Washington State University, United States Aquifers; Heat transfer, Aquifer model; Blackwell Session; Enhanced geothermal; Geothermal; Snake river plains; System, Geothermal fields https://www.scopus.com/inward/record.uri?eid=2-s2.0-84937842384&partnerID=40&md5=c5acf8a4f33884a24eca5bbf0aeea2fb cited By 2 T. McLing M. McCurry C. Cannon G. Neupane T. Wood R. Podgorney J. Welhan G. Mines E. Mattson R. Wood C. Palmer R. Smith conference Heinonen2014117 A network ofhigh resolution seismic reflection profiles was acquired in Outokumpu, Finland. Outokumpu is one of the most important mining regions in Finland where active sulphide exploration is ongoing. Over 5 km long spread with 402 active channels and nominal vibroseismic source point interval of 25 m guarantee high fold and good signal-to-noise ratio of the seismic data. These high quality data have been commercially processed by Vniigeofizika, Moscow with standard hardrock seismic processing flow including careful static corrections. Seismic sections were migrated and depth converted with constant velocity (5400 m/s) that corresponds approximately to the seismic P-wave velocity in the main lithology of the area, mica schist. Additionally to seismic velocities, also densities of the main lithologies have been measured from the 2.5 km long drill hole. This enables estimation of the main sources of reflectivity in the Outokumpu area. Encouragingly, typical ore hosting lithological assemblage was found to be brightly reflective both externally and internally due to interlayers ofhigh acoustic impedance skarns and low acoustic impedance serpentinites. All together nine interconnected seismic profiles combined with the drill hole logging data and other geophysical data, including ZTEM survey, enable the 3D-modeling of the Outokumpu subsurface structures. Conference paper 2014 English 978-163266695-6 10.3997/2214-4609.20140520 76th EAGE Conference and Exhibition 2014, Workshops EAGE Publishing BV 117 – 119 3D modeling; Acoustic impedance; Infill drilling; Lithology; Mica; Mineral exploration; Rock drills; Seismology; Signal to noise ratio; Sulfur compounds; Wave propagation; Constant velocities; High quality data; Seismic processing; Seismic reflection profiles; Seismic reflections; Seismic velocities; Static correction; Subsurface structures; Seismic waves https://www.scopus.com/inward/record.uri?eid=2-s2.0-84907346055&doi=10.3997%2f2214-4609.20140520&partnerID=40&md5=6ca6d352659aff15b2939247e04d80f6 Cited by: 0; All Open Access, Bronze Open Access, Green Open Access S.E. Heinonen S. Aatos P.J. Heikkinen N. Hellqvist M. Kurimo H. Levaniemi I.T. Kukkonen article Zhu2014212 Article 2014 10.1016/j.gca.2014.01.013 Geochimica et Cosmochimica Acta 130 212 – 228 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84894372938&doi=10.1016%2fj.gca.2014.01.013&partnerID=40&md5=463130c31fdfe5995dfe4a491b0e85e1 Cited by: 14 Jiayun Zhu Andreas Lücke Holger Wissel Christoph Mayr Christian Ohlendorf Bernd Zolitschka article nie2014biomarker 2014 Earth Sci. Front. 21 265-274 2 ZY Nie QH Huang DP Xi XQ Wan article INGASON201458 The initial discharge of IDDP-1 took place in March 2010 and the well was discharged intermittently until July 2012. In the beginning a mixture of steam and water flowed from the well but soon the fluid became superheated and enthalpy gradually increased, approaching 3200kJ/kg. The flow rate from the well was up to 50kg/s. The design condition at well head turned out to be challenging due to high pressure, temperature, corrosion and erosion. Valves, rated for higher pressure and temperature, failed during operation. Five different designs of discharge systems were installed. The well had to be quenched when the master valves failed. Plans for its future are still being evaluated. 2014 0375-6505 https://doi.org/10.1016/j.geothermics.2013.05.002 Geothermics 49 58-65 Krafla, IDDP-1, Geothermal well head, Geothermal well discharge, Geothermal superheated steam, Corrosion, Erosion https://www.sciencedirect.com/science/article/pii/S0375650513000394 Iceland Deep Drilling Project:The first well, IDDP-1, drilled into Magma K. Ingason V. Kristjánsson K. Einarsson article Litt201430 Lake Van is the fourth largest terminal lake in the world (38.5°N, 43°E, volume 607km3, area 3570km2, maximum water depth 460m), extending for 130km WSW-ENE on the eastern Anatolian high plateau, Turkey. The sedimentary record of Lake Van, partly laminated, obtains a long and continuous continental sequence that covers multiple interglacial-glacial cycles. Promoted by the potential of the sedimentary sequence for reconstructing the paleoecological and paleoclimate development of the Near East, a deep drilling operation was carried out in 2010 supported by the International Continental Scientific Drilling Program (ICDP). The 219m long continental pollen record presented here is based on a well-dated composite profile drilled on the so-called Ahlat Ridge in water depth of 360m encompassing the last 600,000 years. It is the longest continuous continental pollen record of the Quaternary in the entire Near East and central Asia obtained to date. The glacial-interglacial cycles and pronounced interstadials are clearly reflected in the vegetation development based on millennial-scale time resolution. In general, the glacial/stadial vegetation is characterized by dwarf-shrub steppe and desert steppe, whereas the climax vegetation of past interglacials can be described as oak steppe-forest similar to the present interglacial in this sensitive semi-arid region between the Black, Caspian, and Mediterranean Seas. By comparing the Lake Van pollen record with other western Asian and southern European long continental pollen sequences as well as marine and ice-core records, the regional variability of the climate signals is also discussed. © 2014. 2014 English 02773791 10.1016/j.quascirev.2014.03.017 Quaternary Science Reviews 104 Elsevier Ltd 30-41 University of Bonn, Steinmann Institute of Geology, Mineralogy and Paleontology, Nussallee 8, Bonn, 53115, Germany; Swiss Federal Institute of Technology Zurich (ETH), Climate Geology, Sonneggstr. 5, Zurich, 8092, Switzerland; Eawag, Swiss Federal Institute of Aquatic Science and Technology, Department of Surface Waters Research and Management, Ueberlandstrasse 133, Dübendorf, 8600, Switzerland; Department of Geography, University College London, London, United Kingdom Eastern Anatolia; Lake vans; Long continental pollen record; Near East; Paleoclimates, climax; deciduous tree; deep drilling; glacial-interglacial cycle; ice core; paleoclimate; paleoecology; palynology; Quaternary; sedimentary sequence; water depth, Black Sea; Caspian Sea; Lake Van; Mediterranean Sea; Turkey https://www.scopus.com/inward/record.uri?eid=2-s2.0-84909584452&doi=10.1016%2fj.quascirev.2014.03.017&partnerID=40&md5=efa73281f2c080bc4042679baeaf4802 cited By 108 T. Litt N. Pickarski G. Heumann M. Stockhecke P.C. Tzedakis conference Sun20143650 Velocity dispersion allows special insight into the physical properties of reservoir rocks. The total velocity dispersion may provide a link to rock physical properties, such as permeability and concentration of a certain material, but the shape of a velocity dispersion curve, including the critical frequency (fc), can provide more essential information, such as the existence of different attenuation mechanisms. For this purpose, continuous velocity measurement in a broad frequency band is desirable. In this study, we use broadband full-waveform multi-channel sonic logging data from Mallik gas hydrate research wells and measure the P wave velocity (Vp) dispersion curves with the filter-semblance-correlation (FiSCo) method. Profiles of Vp gradient and accumulated dispersion are obtained. In the profiles, the total Vp dispersion and fc are observed varying with several rock physical properties. The Biot's model is then applied to interpret the results. Also Biot's model can generally fit the results, more realistic models are needed to better describe the complicated geological condition of the gas hydrate reservoir. 2014 English 9781632666949 10.3997/2214-4609.20141029 76th European Association of Geoscientists and Engineers Conference and Exhibition 2014: Experience the Energy - Incorporating SPE EUROPEC 2014 EAGE Publishing BV 3650-3654 China University of Petroleum -Beijing, China; University of Toronto, Canada Acoustic logging; Acoustic wave velocity; Gas hydrates; Hydration; Physical properties; Seismic waves; Wave propagation, Accumulated dispersion; Complicated geological conditions; Critical frequencies; Dispersion curves; Gas hydrate reservoir; Reservoir characteristic; Rock physical properties; Velocity dispersion, Dispersion (waves) https://www.scopus.com/inward/record.uri?eid=2-s2.0-84907409357&doi=10.3997%2f2214-4609.20141029&partnerID=40&md5=18116eca736379c8c32695c61d8174c9 cited By 1 L.F. Sun B. Milkereit article Losiak2014394 Rocks from drill cores LB-07A (crater fill) and LB-08A (central uplift) into the Bosumtwi impact crater, Ghana, were analyzed for the presence of the cosmogenic radionuclide 10Be. The aim of the study was to determine the extent to which target rocks of various depths were mixed during the formation of the crater-filling breccia, and also to detect meteoric water infiltration within the impactite layer. 10Be abundances above background were found in two (out of 24) samples from the LB-07A core, and in none of five samples from the LB-08A core. After excluding other possible explanations for an elevated 10Be signal, we conclude that it is most probably due to a preimpact origin of those clasts from target rocks close to the surface. Our results suggest that in-crater breccias were well mixed during the impact cratering process. In addition, the lack of a 10Be signal within the rocks located very close to the lake sediment-impactite boundary suggests that infiltration of meteoric water below the postimpact crater floor was limited. This may suggest that the infiltration of the meteoric water within the crater takes place not through the aerial pore-space, but rather through a localized system of fractures. © The Meteoritical Society, 2014. Article 2014 English 10869379 10.1111/maps.12256 Meteoritics and Planetary Science 49 University of Arkansas 394 – 411 3 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84897022155&doi=10.1111%2fmaps.12256&partnerID=40&md5=e7312e686417090b078d22c67b6a7b34 Cited by: 3 Anna Losiak Eva Maria Wild Leonard Michlmayr Christian Koeberl article Zhou2014143 Radiocarbon accelerator mass spectrometry (AMS) techniques were used to date total organic carbon and plant seeds in the 1Fs core sequence (36°48′N, 100°08′E) from Qinghai Lake, China. This core was drilled ~18 m into Qinghai Lake sediments as part of an international cooperative research project, "Scientific Drilling at Qinghai Lake in the Northeastern Tibetan Plateau: High-Resolution Paleoenvironmental Records of Eastern Asia Linked to Global Change," which began in 2004. Based on the differences in lithology and total organic content (TOC) in core 1Fs, the core was divided into 3 sections for age-modeling purposes: the upper ~499 cm lacustrine silty clay to clay; the middle unit of silty clay with silt layers from 499-901 cm; and the lower 901-1861 cm silty clay, loess-like silt, and fine sand layers. Three different approaches are applied to the reservoir age problem. First, a simple linear regression gives an offset of 1342 yr. If the core is divided into three sections, linear regressions can be applied separately for the three segments, which results in an age estimate for the average hardwater effect of ~135 yr BP for the surface section up to 499 cm. If extrapolated for deeper sections, these results imply a higher reservoir offset for those two sections, which may be as much as 1143 and 2523 yr, but this assumes that there are no discontinuities in the core. A third approach using a wiggle-matching approach gave an offset of 196 yr. This study concludes that the reservoir age of Qinghai Lake is complex, but these new data add to our understanding of the 14C chronology of Qinghai Lake for the last 32 ka. © 2014 by the Arizona Board of Regents on behalf of the University of Arizona. Article 2014 English 00338222 10.2458/56.16470 Radiocarbon 56 143 – 155 1 China; Qinghai; Qinghai Lake; accelerator mass spectrometry; age determination; chronostratigraphy; lacustrine deposit; lake ecosystem; radiocarbon dating; reservoir; total organic carbon https://www.scopus.com/inward/record.uri?eid=2-s2.0-84896900415&doi=10.2458%2f56.16470&partnerID=40&md5=49cabab88516f25a54abaf4a79dae488 Cited by: 43 Weijian Zhou Peng Cheng A.J. Timothy Jull Xuefeng Lu ZhiSheng An Hao Wang Yizhi Zhu Zhenkun Wu article hedin_3d_2014 Skip to Next Section The scientific drilling project COSC (Collisional Orogeny in the Scandinavian Caledonides), designed to study key questions concerning orogenic processes, aims to drill two fully cored boreholes to depths of c. 2.5 km each at carefully selected locations in west-central Sweden. The first of these, COSC-1, is scheduled for start late spring 2014 and will target the Seve Nappe Complex, characterized by inverted metamorphism and with parts that have evidently been subjected to hot ductile extrusion. In this study available seismic sections have been combined with surface geology to produce a 3D interpretation of the tectonic structures in the vicinity of the COSC-1 borehole. Constrained 3D inverse gravity modelling over the same area supports the interpretation, and the high-density Seve Nappe Complex stands out clearly in the model. Interpretation and models show that the maximum depth extent of the Seve Nappe Complex is less than 2.5 km, consistent with reflection seismic data. The gravity modelling also requires underlying units to comprise low-density material, consistent with the Lower Allochthon, but the modelling is unable to discern the décollement separating the allochthons from the crystalline Precambrian basement. 2014 jan en 0305-8719, 2041-4927 10.1144/SP390.15 Geological Society, London, Special Publications 390 301--319 1 https://sp.lyellcollection.org/content/390/1/301 Publisher: Geological Society of London Section: Development of the Seve nappe complex and its position within the orogen Peter Hedin Alireza Malehmir David G. Gee Christopher Juhlin Dan Dyrelius article Warr2014234 The San Andreas Fault is one of the most studied earthquake-generating structures on Earth, but the reason that some sections are anomalously weak, and creep without apparent seismicity, remains poorly understood. Here, we present results from nanoscale (FIB-SEM) 3D microstructural observations of weak (friction coefficient of 0.095) SAFOD clay fault gouge containing serpentinite clasts, recovered from the active Central Deforming Zone at ~2.7km vertical depth. Our nanoscale observations confirm that frictional slip and extreme weakness occurvia deformation of smectite clay that forms a shear fabric within the fault zone. We infer that creep initiates by fracture-controlled, substrate growth of oriented Mg-smectite on R, P and Y shears, followed by clay smearing and ductile flow of an evolving and expanding clay matrix. At the crystal-scale, pervasive sliding occurs along hydrated smectite interlayers and surfaces occupied by exchangeable Mg- and Ca-ions, with slip typically spaced at 3-5 lattice layers apart. We conclude that the strength and seismic behaviour of major tectonic faults at shallow crustal levels evolves as clay fabric develops with accumulated fault slip. © 2014 Elsevier Ltd. 2014 English 01918141 10.1016/j.jsg.2014.10.006 Journal of Structural Geology 69 Elsevier Ltd 234-244 Institut für Geographie und Geologie, Ernst-Moritz-Arndt Universität Greifswald, F.L. Jahn-Str. 17a, Greifswald, 17487, Germany; INGV, Section, Via di Vigna Murata 605, Rome, 00143, Italy; Department of Geosciences Center for Geomechanics, Geofluids and Geohazards, The Pennsylvania State University, University Park, PA 16802, United States; Department of Earth and Environmental Sciences, University of Michigan, 1100 University Ave, Ann Arbor, MI 48109, United States PA Clay fabrics; SAFOD; San Andreas fault; SEM and TEM; Smectites, Creep, creep; deformation; fault gouge; fault zone; magnesium; San Andreas Fault; scanning electron microscopy; seismicity; smectite; transmission electron microscopy https://www.scopus.com/inward/record.uri?eid=2-s2.0-84909579317&doi=10.1016%2fj.jsg.2014.10.006&partnerID=40&md5=3afcb654bca961b37a130b3961fa5b13 cited By 24 L.N. Warr J. Wojatschke B.M. Carpenter C. Marone A.M. Schleicher B.A. Pluijm article Fornace2014263 A record of the hydrogen isotopic composition of terrestrial leaf waxes (δDwax) in sediment cores from Lake Titicaca provides new insight into the precipitation history of the Central Andes and controls of South American Summer Monsoon (SASM) variability since the last glacial period. Comparison of the δDwax record with a 19-kyr δD record from the nearby Illimani ice core supports the interpretation that precipitation δD is the primary control on δDwax with a lesser but significant role for local evapotranspiration and other secondary influences on δDwax. The Titicaca δDwax record confirms overall wetter conditions in the Central Andes during the last glacial period relative to a drier Holocene. During the last deglaciation, abrupt δDwax shifts correspond to millennial-scale events observed in the high-latitude North Atlantic, with dry conditions corresponding to the Bølling-Allerød and early Holocene periods and wetter conditions during late glacial and Younger Dryas intervals. We observe a trend of increasing monsoonal precipitation from the early to the late Holocene, consistent with summer insolation forcing of the SASM, but similar hydrologic variability on precessional timescales is not apparent during the last glacial period. Overall, this study demonstrates the relative importance of high-latitude versus tropical forcing as a dominant control on glacial SASM precipitation variability. © 2014 Elsevier B.V. Article 2014 10.1016/j.epsl.2014.10.024 Earth and Planetary Science Letters 408 263 – 271 Lake Titicaca; Central Andes; Holocenes; Hydrogen isotopic composition; Last glacial period; Stable hydrogen isotope; Summer monsoon; deglaciation; glacial lake; Holocene; hydrogen isotope; isotopic composition; Last Glacial Maximum; monsoon; precipitation (chemistry); sediment core; stable isotope; summer; Younger Dryas https://www.scopus.com/inward/record.uri?eid=2-s2.0-84910089298&doi=10.1016%2fj.epsl.2014.10.024&partnerID=40&md5=64814f33c1246a85b7de93af53a3091d Cited by: 31; All Open Access, Green Open Access Kyrstin L. Fornace Konrad A. Hughen Timothy M. Shanahan Sherilyn C. Fritz Paul A. Baker Sean P. Sylva article Anders20142871 The Heise and Picabo volcanic fields of eastern Idaho are part of the more extensive time-transgressive Yellowstone-Snake River Plain hotspot track. Calderas associated with these two silicic volcanic fields are buried under 1 to 3 km of younger basalt, so their locations and eruption record histories have been based on analysis of silicic units along the margins of the eastern Snake River Plain along with some limited geophysical data. A 1.5 km borehole penetrating through basalt into underlying silicic rocks provides new data we used to reassess caldera locations and the timing of eruptions of these volcanic fields. Using these new caldera locations, we calculate an extension-adjusted rate of 2.35 cm/yr for the North American plate over the last 6.66 m.y. and a velocity of 2.30 cm/yr over the 10.27 m.y. Recalculation of a previously determined plate velocity-based migration of the deformation field surrounding the eastern Snake River Plain yields an extension-adjusted rate of 2.38 ± 0.21 cm/yr. These migration rates all fall within the previously published range of North American plate velocities of 2.2 ± 0.8 cm/yr, 2.4 cm/yr, and 2.68 ± 0.78 cm/yr based on a global hot spot reference frame. The consistency of these rates suggest that over the last 10 m.y., the Yellowstone hot spot is fixed with respect to the motion of the North American plate and therefore consistent with a classical deep-sourced hotspot model. ©2014. American Geophysical Union. All Rights Reserved. 2014 English 21699313 10.1002/2013JB010483 Journal of Geophysical Research: Solid Earth 119 Blackwell Publishing Ltd 2871-2906 Department of Earth and Environmental Sciences and Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY, United States; Department of Geosciences, Idaho State University, Pocatello, ID, United States; Science Department, Red Hook High School, Red Hook, NY, United States; Department of Earth and Environmental Science, Long Island University, Brookville, NY, United States; U.S. Geological Survey, Menlo Park, CA, United States; Department of Geology, Brigham Young University Idaho, Rexburg, ID, United States; Department of Earth and Environment, Franklin and Marshall College, Lancaster, PA, United States 4 basalt; caldera; deformation; hot spot; ignimbrite; lithospheric structure; Neogene; North American plate; volcanic eruption; volcanic landform, Idaho; Snake River Plain; United States; Yellowstone River https://www.scopus.com/inward/record.uri?eid=2-s2.0-84901020438&doi=10.1002%2f2013JB010483&partnerID=40&md5=489f853cb6a6a54da01dded980e86d36 cited By 20 M.H. Anders D.W. Rodgers S.R. Hemming J. Saltzman V.J. Divenere J.T. Hagstrum G.F. Embree R.C. Walter article cp-10-209-2014 A number of studies have shown that Fourier transform infrared spectroscopy (FTIRS) can be applied to quantitatively assess lacustrine sediment constituents. In this study, we developed calibration models based on FTIRS for the quantitative determination of biogenic silica (BSi; <i>n</i> Combining double low line 420; gradient: 0.9-56.5%), total organic carbon (TOC; <i>n</i> Combining double low line 309; gradient: 0-2.9%), and total inorganic carbon (TIC; <i>n</i>Combining double low line 152; gradient: 0-0.4%) in a 318 m-long sediment record with a basal age of 3.6 million years from Lake El'gygytgyn, Far East Russian Arctic. The developed partial least squares (PLS) regression models yield high cross-validated (CV) <i>R</i>2CV Combining double low line 0.86-0.91 and low root mean square error of cross-validation (RMSECV) (3.1-7.0% of the gradient for the different properties). By applying these models to 6771 samples from the entire sediment record, we obtained detailed insight into bioproductivity variations in Lake El'gygytgyn throughout the middle to late Pliocene and Quaternary. High accumulation rates of BSi indicate a productivity maximum during the middle Pliocene (3.6-3.3 Ma), followed by gradually decreasing rates during the late Pliocene and Quaternary. The average BSi accumulation during the middle Pliocene was ∼3 times higher than maximum accumulation rates during the past 1.5 million years. The indicated progressive deterioration of environmental and climatic conditions in the Siberian Arctic starting at ca. 3.3 Ma is consistent with the first occurrence of glacial periods and the finally complete establishment of glacial-interglacial cycles during the Quaternary. ©Author(s) 2014. 2014 English 18149324 10.5194/cp-10-209-2014 Climate of the Past 10 209-220 Department of Ecology and Environmental Science, Umea University, 901 87 Umea, Sweden; Institute of Geology and Mineralogy, University of Cologne, Zuelpicher Str. 49a, 50674 Cologne, Germany; Institute of Geological Sciences and Oeschger Centre for Climate Change Research, University of Bern, Baltzerstrasse 1 + 3, 3012 Bern, Switzerland; Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Columbusstraße, 27515 Bremerhaven, Germany; Climate Impacts Research Centre (CIRC), Abisko Scientific Research Station, 981 07 Abisko, Sweden 1 accumulation rate; climate variation; FTIR spectroscopy; glacial-interglacial cycle; paleoclimate; Quaternary; regression analysis, Chukchi; Elgygytgyn Lake; Far East; Russian Federation https://cp.copernicus.org/articles/10/209/2014/ cited By 19 C. Meyer-Jacob H. Vogel A. C. Gebhardt V. Wennrich M. Melles P. Rosen article Johri20142057 We analyze fracture-density variations in subsurface fault-damage zones in two distinct geologic environments, adjacent to faults in the granitic SSC reservoir and adjacent to faults in arkosic sandstones near the San Andreas fault in central California. These damage zones are similar in terms of width, peak fracture or fault (FF) density, and the rate of FF density decay with distance from the main fault. Seismic images from the SSC reservoir exhibit a large basement master fault associated with 27 seismically resolvable second-order faults. A maximum of 5 to 6 FF/m (1.5 to 1.8 FF/ft) are observed in the 50 to 80 m (164 to 262 ft) wide damage zones associated with second-order faults that are identified in image logs from four wells. Damage zones associated with second-order faults immediately southwest of the San Andreas Fault are also interpreted using image logs from the San Andreas Fault Observatory at Depth (SAFOD) borehole. These damage zones are also 50-80 m wide (164 to 262 ft) with peak FF density of 2.5 to 6 FF/m (0.8 to 1.8 FF/ft). The FF density in damage zones observed in both the study areas is found to decay with distance according to a power law F = F0r-n. The fault constant F0 is the FF density at unit distance from the fault, which is about 10-30 FF/m (3.1-9.1 FF/ft) in the SSC reservoir and 6-17 FF/m (1.8-5.2 FF/ft) in the arkose. The decay rate n ranges from 0.68 to 1.06 in the SSC reservoir, and from 0.4 to 0.75 in the arkosic section. This quantification of damage-zone attributes can facilitate the incorporation of the geometry and properties of damage zones in reservoir flow simulation models. Copyright © 2014. The American Association of Petroleum Geologists. All rights reserved. 2014 English 01491423 10.1306/05061413173 AAPG Bulletin 98 American Association of Petroleum Geologists 2057-2079 Department of Geophysics, 397 Panama Mall, Stanford UniversityCA 94305, United States; BP America, 501 Westlake Park Blvd., Houston, TX 77079, United States; ConocoPhillips Technology and Projects, 600 N. Dairy Ashford, Houston, TX 77079, United States 10 Boreholes; Decay (organic); Well logging, Density decay; Fault damage zone; Fracture density; Geologic environment; Reservoir flow; San Andreas fault; Second orders; Seismic image, Strike-slip faults, damage mechanics; fault geometry; fault plane; fault propagation; fracture zone; sandstone; seismic stratigraphy; simulation, California; California; San Andreas; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-84916912288&doi=10.1306%2f05061413173&partnerID=40&md5=781cd0f5f4e45fee5e65caee0d4bdf3a cited By 53 M. Johri M.D. Zoback P. Hennings article Liu2014223 We inferred the climate history for Central Asia over the past 20,000 years, using sediments from core QH07, taken in the southeastern basin of Lake Qinghai, which lies at the northeastern margin of the Tibetan Plateau. Results from multiple environmental indicators are internally consistent and yield a clear late Pleistocene and Holocene climate record. Carbonate content and total organic carbon (TOC) in Lake Qinghai sediments are interpreted as indicators of the strength of the Asian summer monsoon. Warm and wet intervals, associated with increased monsoon strength, are indicated by increased carbonate and TOC content. During the glacial period (~20,000 to ~14,600 cal year BP), summer monsoon intensity remained low and relatively constant at Lake Qinghai, suggesting cool, dry, and relatively stable climate conditions. The inferred stable, cold, arid environment of the glacial maximum seems to persist through the Younger Dryas time period, and little or no evidence of a warm interval correlative with the Bølling-Allerød is found in the QH07 record. The transition between the late Pleistocene and the Holocene, about 11,500 cal year BP, was abrupt, more so than indicated by speleothems in eastern China. The Holocene (~11,500 cal year BP to present) was a time of enhanced summer monsoon strength and greater variability, indicating relatively wetter but more unstable climatic conditions than those of the late Pleistocene. The warmest, wettest part of the Holocene, marked by increased organic matter and carbonate contents, occurred from ~11,500 to ~9,000 cal year BP, consistent with maximum summer insolation contrast between 30°N and 15°N. A gradual reduction in precipitation (weakened summer monsoon) is inferred from decreased carbonate content through the course of the Holocene. We propose that changes in the contrast of summer insolation between 30°N and 15°N are the primary control on the Asian monsoon system over glacial/interglacial time scales. Secondary influences may include regional and global albedo changes attributable to ice-cover and vegetation shifts and sea level changes (distance from moisture source in Pacific Ocean). The abruptness of the change at the beginning of the Holocene, combined with an increase in variability, suggest a threshold for the arrival of monsoonal rainfall at the northeastern edge of the Tibetan Plateau. © 2013 Springer Science+Business Media Dordrecht. Article 2014 English 09212728 10.1007/s10933-013-9721-y Journal of Paleolimnology 51 Kluwer Academic Publishers 223 – 240 2 China; Qinghai; Qinghai Lake; Qinghai-Xizang Plateau; climate conditions; deglaciation; environmental indicator; Holocene; paleoclimate; precipitation (climatology); sediment analysis; timescale https://www.scopus.com/inward/record.uri?eid=2-s2.0-84895068029&doi=10.1007%2fs10933-013-9721-y&partnerID=40&md5=21b8fffb1dd8fdd3f79c74e6ff901257 Cited by: 33; All Open Access, Green Open Access Xiuju Liu Steven M. Colman Erik T. Brown Andrew C.G. Henderson Josef P. Werne Jonathan A. Holmes article Sun20145 Continental scientific drilling is an important scientific and engineering project that has been attracting world-wide attentions. Since International Continental Scientific Drilling Program (ICDP) was founded in 1996, great advances have been brought about in many fields of earth sciences by continental scientific drilling. As one of the three founding members of ICDP, China has also achieved a lot of developments in continental scientific drilling. This paper summarizes the continental scientific drilling projects in China, such as the Chinese Continental Scientific Drilling (CCSD), the Lake Qinghai Scientific Drilling Project(CESD), and the preliminary progresses of the third approved ICDP project of China--the Chinese Cretaceous Continental Scientific Drilling Project(SK-I,SK-II project). The implementing Wenchuan Fault Scientific Drilling Program (WFSD) is also included in the paper. Their scientific objectives, drilling and coring situations and drilling equipment used in the project are all introduced. © 2014 CAFET-INNOVA TECHNICAL SOCIETY. 2014 English 09745904 International Journal of Earth Sciences and Engineering 7 CAFET INNOVA Technical Society 5-15 College of Construction Engineering, Jilin University, Changchun, China 1 Engineering; Industrial engineering, Continental scientific drillings; Coring situation; Engineering project; Lake Qinghai; Scientific drilling; Scientific objectives, Drilling equipment; Drilling equipment, Chinese Continental Scientific Drilling Project; deep drilling; Earth science; regional geology; Earth structure; equipment; international organization, China https://www.scopus.com/inward/record.uri?eid=2-s2.0-84905008009&partnerID=40&md5=a24aff634cb29c1752ae17c42c319ff9 cited By 1 Y.H. Sun J.S. Mao B.C. Liu X.P. Fan article Sun20145 Continental scientific drilling is an important scientific and engineering project that has been attracting world-wide attentions. Since International Continental Scientific Drilling Program (ICDP) was founded in 1996, great advances have been brought about in many fields of earth sciences by continental scientific drilling. As one of the three founding members of ICDP, China has also achieved a lot of developments in continental scientific drilling. This paper summarizes the continental scientific drilling projects in China, such as the Chinese Continental Scientific Drilling (CCSD), the Lake Qinghai Scientific Drilling Project(CESD), and the preliminary progresses of the third approved ICDP project of China--the Chinese Cretaceous Continental Scientific Drilling Project(SK-I,SK-II project). The implementing Wenchuan Fault Scientific Drilling Program (WFSD) is also included in the paper. Their scientific objectives, drilling and coring situations and drilling equipment used in the project are all introduced. © 2014 CAFET-INNOVA TECHNICAL SOCIETY. 2014 English 09745904 International Journal of Earth Sciences and Engineering 7 CAFET INNOVA Technical Society 5-15 College of Construction Engineering, Jilin University, Changchun, China 1 Engineering; Industrial engineering, Continental scientific drillings; Coring situation; Engineering project; Lake Qinghai; Scientific drilling; Scientific objectives, Drilling equipment; Drilling equipment, Chinese Continental Scientific Drilling Project; deep drilling; Earth science; regional geology; Earth structure; equipment; international organization, China https://www.scopus.com/inward/record.uri?eid=2-s2.0-84905008009&partnerID=40&md5=a24aff634cb29c1752ae17c42c319ff9 cited By 1 Y.H. Sun J.S. Mao B.C. Liu X.P. Fan article Acarel20141954 We analyze the ambient seismic-noise field in order to investigate the crustal structure at the North Anatolian fault zone (NAFZ) in northwest Turkey. We focus on the eastern Sea of Marmara section, where the NAFZ is in the final phase of the seismic cycle prior to an expected major (M >7) earthquake. We apply crosscorrelation analysis of the seismic ambient noise to determine the spectral dependence of the seismic velocity in order to image the crustal structure at seismogenic depth. Time-domain cross correlations are calculated for available station pairs in the target area. Interstation distances span 0.3-90 km. Here, the vertical component is analyzed in order to recover fundamental-mode Rayleigh waves in the 0.05-1.1 Hz frequency range. Group velocity dispersion curves are obtained for selected correlation paths in particular to address the azimuthal dependence of the velocity field. In the frequency band of interest, average group velocities range between ~1:8 and 3:5 km=s. Dispersion curves corresponding to the north-south-trending paths crossing the main NAFZ fault branch below the eastern Sea of Marmara show low group velocities between ~1:5 and 1:8 km=s, which is well explained by the 3-4 km-deep Çi{dotless}narci{dotless}k basin, located between the two major fault branches, the Princes Islands and Armutlu fault segments. In contrast, ray paths restricted to within the mainland of Istanbul and the Armutlu peninsulas (primarily trending east-west) show higher group velocities up to 3:2 km=s. By averaging the dispersion curves, we determine an optimized 1D S-wave velocity model for the eastern Sea of Marmara region, allowing for a significant improvement in hypocenter determination for local seismicity. 2014 English 00371106 10.1785/0120130160 Bulletin of the Seismological Society of America 104 Seismological Society of America 1954-1963 GFZ German Research Center for Geosciences, Section 3.2 Geomechanics and Rheology, Telegrafenberg, 14473 Potsdam, Germany; Free University Berlin, Institute of Geological Sciences, Berlin, Germany 4 Acoustic noise; Frequency bands; Group velocity dispersion; Light velocity; Wave propagation, Azimuthal dependence; Cross correlations; Cross-correlation analysis; Group velocity dispersion curve; Low group velocity; North Anatolian Fault Zone; Seismic velocities; Spectral dependences, Earthquakes, ambient noise; crustal structure; dispersion; earthquake hypocenter; North Anatolian Fault; S-wave; seismic noise; seismic velocity; seismicity; spectral analysis, Sea of Marmara; Turkey https://www.scopus.com/inward/record.uri?eid=2-s2.0-84905675453&doi=10.1785%2f0120130160&partnerID=40&md5=63b88298b14aa2ce2073ba76568e77ba cited By 1 D. Acarel F. Bulut M. Bohnhoff article Whalen2014282 Stratigraphic analysis of the Yaxcopoil-1 core (Yax-1) and seismic analysis of offshore two-dimensional (2D) seismic data provide insight into the Paleogene history of the Chicxulub impact basin and Yucatàn platform development. Ten facies were identified based on core and petrographic analysis. Slope sediments include redeposited and background facies. The former are carbonate supportstones and finer-grained facies with evidence of soft sediment deformation deposited as gravity flows. Background facies are shales and mud-wackestone interpreted as sub-storm wave base suspension deposits. Depositional setting ranged from a steep bathyal slope inside the crater rim to neritic outer carbonate platform environments of the seaward prograding Yucatàn platform. Through sequence stratigraphic analysis of Yax-1, we documented five sequences based on identification of transgressive and maximum flooding surfaces and facies stacking patterns. Biostratigraphic ages are equivocal, but they imply that sequences 1 and 2 are Early Paleocene, sequences 3 and 4 are Early Eocene, and sequence 5 is Middle Eocene. Coarse-grained redeposited carbonates in lower sequences 1 to 4 indicate slope gravity flow processes. Upper sequence 3 records the first evidence of fine-grained turbidites, indicating progradation of the Yucatàn platform. By the top of sequence 4, facies indicate that the platform margin had prograded over the position of Yax-1. Seismic analysis identified six units, the lower five of which appear to correlate with cored Yax-1 sequences. The geometry and distribution of seismic units A and B indicate deposition confined to the western and central parts of the basin. Unit C, with two sets of clinoforms, records a major progradational event in the eastern part of the basin likely related to Yax-1 sequence 3 turbidites. Mainly parallel reflectors in seismic units D and E indicate relatively level bottom conditions similar to the environments of facies in upper sequence 4 and 5. The tops of units D and E, in proximal settings, are erosionally truncated. This unconformity marks the base of unit F, which is characterized by discontinuous reflectors and is restricted to the northeastern portion of the basin. Stratal patterns in seismic units C to E are more controlled by relative sea-level change, as suggested by the development of clinoforms and regional unconformities. If Chicxulub and others like the Chesapeake Bay structure are representative, large marine impacts in tectonically quiescent regions may dominate local depositional environments for millions to tens of millions of years postimpact before returning control to eustasy. Copyright © 2013 SEPM (Society for Sedimentary Geology). 2014 10.2110/sepmsp.105.04 SEPM Special Publications 105 282-304 Department of Geology and Geophysics, University of Alaska-Fairbanks, Fairbanks, AK 99775, United States; Institute for Geophysics, Jackson School of Geosciences, University of Texas at Austin, J.J. Pickle Research Campus, 10100 Burnet Road, Austin, TX 78758, United States; Scripps Institution of Oceanography, 301 Vaughan Hall, MS-0244, San Diego, CA 92093, United States; Instituto de Geofisica, Universidad Nacional Autónoma de México, Ciudad Universitaria, Mexico City, CP 04510, Mexico https://www.scopus.com/inward/record.uri?eid=2-s2.0-84957872527&doi=10.2110%2fsepmsp.105.04&partnerID=40&md5=39840355b7bf2b0c0c42d6786feea449 cited By 11 M.T. Whalen S.S.P. Gulick Z.F. Pearson R.D. Norris L.P. Cruz J.U. Fucugauchi article Morrow201499 The San Andreas Fault Observatory at Depth (SAFOD) scientific borehole near Parkfield, California crosses two actively creeping shear zones at a depth of 2.7km. Core samples retrieved from these active strands consist of a foliated, Mg-clay-rich gouge containing porphyroclasts of serpentinite and sedimentary rock. The adjacent damage zone and country rocks are comprised of variably deformed, fine-grained sandstones, siltstones, and mudstones. We conducted laboratory tests to measure the permeability of representative samples from each structural unit at effective confining pressures, Pe up to the maximum estimated in situ Pe of 120MPa. Permeability values of intact samples adjacent to the creeping strands ranged from 10-18 to 10-21m2 at Pe=10MPa and decreased with applied confining pressure to 10-20-10-22m2 at 120MPa. Values for intact foliated gouge samples (10-21-6×10-23m2 over the same pressure range) were distinctly lower than those for the surrounding rocks due to their fine-grained, clay-rich character. Permeability of both intact and crushed-and-sieved foliated gouge measured during shearing at Pe≥70MPa ranged from 2 to 4×10-22m2 in the direction perpendicular to shearing and was largely insensitive to shear displacement out to a maximum displacement of 10mm. The weak, actively-deforming foliated gouge zones have ultra-low permeability, making the active strands of the San Andreas Fault effective barriers to cross-fault fluid flow. The low matrix permeability of the San Andreas Fault creeping zones and adjacent rock combined with observations of abundant fractures in the core over a range of scales suggests that fluid flow outside of the actively-deforming gouge zones is probably fracture dominated. © 2013. 2014 English 01918141 10.1016/j.jsg.2013.09.009 Journal of Structural Geology 64 Elsevier Ltd 99-114 U.S. Geological Survey, 345 Middlefield Road, MS 977 Menlo Park, CA 94025, United States Clay minerals; Deformation; Flow of fluids; Fracture; Mechanical permeability; Observatories; Rock pressure; Shearing; Strike-slip faults, Confining pressures; Fault gouge; Low matrix permeability; Maximum displacement; Representative sample; SAFOD; San Andreas fault; Shear displacement, Core samples, confining pressure; country rock; displacement; fault gouge; permeability; San Andreas Fault; sedimentary rock; serpentinite; shear zone, California; San Andreas; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-84901266017&doi=10.1016%2fj.jsg.2013.09.009&partnerID=40&md5=a49b4a39f14de9484af63d65a49b50b8 cited By 33 C.A. Morrow D.A. Lockner D.E. Moore S. Hickman article Randlett201453 Fossil long-chain alkenones have been used for several decades to reconstruct past ocean surface water temperatures and gained recent interest as a paleotemperature proxy for continental lake settings. However, factors besides temperature can affect alkenone distributions in haptophyte algae, and alkenone compositions can differ between haptophyte species. Alkenone-biosynthesizing haptophyte algae are genetically much more diverse in lakes than in the marine realm, and species-level variations in alkenone compositions could have implications for alkenone paleothermometry. Here, we performed a paired analysis of alkenone distributions and haptophyte species compositions using ancient DNA in up to 270ka-old sediments of Lake Van in Turkey to reveal a possible species-effect on fossil alkenone distributions and paleotemperature estimates. The same predominant haptophyte in Lake Van today prevailed also since the last ~100ka. However, a calibration of alkenone paleotemperature especially in the oldest analyzed intervals is complicated due to a more complex haptophyte species composition predominated by a haptophyte (LVHap_6), which is phylogenetically different from sequences recovered from currently existing lakes including Lake Van and from haptophyte species existing in culture. The predominance of LVHap_6 coincided with the presence of alkenone MeC38:3 and relatively high MeC37:3/4 (2.4) and MeC38:4/5 ratios (3.0). Uk37 index values in the sediment core over the last 270ka reflect relative changes in past temperature and are additionally linked to haptophyte species composition. A sustained period of high salinity, as indicated by pore-water salinity measurements, could potentially have triggered the succession of haptophytes as sources of alkenones in Lake Van. © 2014 The Authors. 2014 English 02773791 10.1016/j.quascirev.2014.07.009 Quaternary Science Reviews 104 Elsevier Ltd 53-62 Eawag, Swiss Federal Institute of Aquatic Science and Technology, Department of Surface Waters - Research and Management, Kastanienbaum, 6047, Switzerland; ETH Zurich, Institute of Biogeochemistry and Pollutant Dynamics, Zurich, 8092, Switzerland; WHOI Woods Hole Oceanographic Institution, Marine Chemistry and Geochemistry Department, Woods Hole, MA 02543, United States; Eawag, Department of Surface Water - Research and Management, Dübendorf, 8600, Switzerland; University of Bonn, Steinmann Institute of Geology, Mineralogy and Paleontology, Bonn, 53115, Germany; Eawag, Water Resources and Drinking Water, Dübendorf, 8600, Switzerland Algae; Biomarkers; Lakes; Paleolimnology; Salinity measurement; Sediments, Alkenones; Haptophyte species; Lake vans; Long chain alkenones; Paleoproxy; Paleotemperature proxy; Paleotemperatures; Species composition, Population distribution, alga; alkenone; biomarker; fossil record; lacustrine deposit; paleolimnology; paleotemperature; reconstruction; spatial distribution; temperature effect, Lake Van; Turkey https://www.scopus.com/inward/record.uri?eid=2-s2.0-84909579815&doi=10.1016%2fj.quascirev.2014.07.009&partnerID=40&md5=46666f3d94df8cd717554da0f7778d25 cited By 59 M.-E. Randlett M.J.L. Coolen M. Stockhecke N. Pickarski T. Litt C. Balkema O. Kwiecien Y. Tomonaga B. Wehrli C.J. Schubert article French20141777 The strength of clay-rich gouge from the Central Deforming Zone (CDZ) of the San Andreas Fault (SAF) was measured using a high-speed rotary shear apparatus to evaluate the potential for unstable slip along the creeping segment of the SAF. Wet and dry gouge was sheared at 0.1-1.3 m/s, 0.5-1.5 MPa normal stress, and 1-20 m displacement. CDZ gouge is weaker wet than dry and exhibits displacement strengthening to peak friction followed by weakening to steady state strength that decreases with increasing velocity. A clay foliation (Unit 2) develops from the initial microstructure (Unit 1) during the first 1.5 m of slip coincident with increasing strength. Subsequent weakening occurs during shear within Unit 2, and subsequently with development of a localized foliated slip zone (Unit 4) and fluidized material (Unit 3). Displacement and dynamic weakening result from slip along clay foliation assisted by shear-heating pressurization of pore fluid in wet gouge and additional grain-size reduction and possible clay dehydration in dry gouge. Peak strength is proportional to normal stress, but steady state strength is insensitive to normal stress probably because pore pressure approaches the normal stress. As such, CDZ gouge is weak at coseismic rates relative to interseismic creep strength. The potential for sustaining rupture propagation into the CDZ from an adjacent seismic segment is sensitive to the relationship used to extrapolate the critical weakening displacement from experimental to in situ conditions. Rupture propagation from a microseismic patch within the CDZ is unlikely, but sustained propagation from a large earthquake (e.g., Parkfield event) may be possible. ©2014. American Geophysical Union. All Rights Reserved. 2014 English 21699313 10.1002/2013JB010757 Journal of Geophysical Research: Solid Earth 119 Blackwell Publishing Ltd 1777-1802 Department of Geology and Geophysics, Center for Tectonophysics, Texas A and M University, College Station, TX, United States; Geological Survey of Japan, National Institute of Advanced Industrial Science and Technology, Tsukuba, Japan; Kochi Institute for Core Sample Research, JAMSTEC, Nankoku, Japan 3 clay; coseismic process; dehydration; displacement; fault gouge; grain size; microstructure; pore pressure; San Andreas Fault; smectite; stress analysis, California; San Andreas; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-84923309339&doi=10.1002%2f2013JB010757&partnerID=40&md5=574bf0d05df2ef52d19933796b79bc17 cited By 32 M.E. French H. Kitajima J.S. Chester F.M. Chester T. Hirose article Menzies20141 Rapid tectonic uplift on the Alpine Fault, New Zealand, elevates topography, regional geothermal gradients, and the depth to the brittle ductile transition, and drives fluid flow that influences deformation and mineralisation within the orogen. Oxygen and hydrogen stable isotopes, fluid inclusion and Fourier Transform Infrared (FT-IR) analyses of quartz from veins which formed at a wide range of depths, temperatures and deformation regimes identify fluid sources and the depth of penetration of meteoric waters. Most veins formed under brittle conditions and with isotope signatures (δ18OH2O = -9.0 to +8.7‰VSMOW and δD = - 73 to - 45‰VSMOW) indicative of progressively rock-equilibrated meteoric waters. Two generations of quartz veins that post-date mylonitic foliation but endured further ductile deformation, and hence formation below the brittle to ductile transition zone (&gt;6-8 km depth), preserve included hydrothermal fluids with δD values between -84 and -52‰, indicating formation from meteoric waters. FT-IR analyses of these veins show no evidence of structural hydrogen release, precluding this as a source of low δD values. In contrast, the oxygen isotopic signal of these fluids has almost completely equilibrated with host rocks (δ18OH2O = +2.3 to +8.7‰). These data show that meteoric waters dominate the fluid phase in the rocks, and there is no stable isotopic requirement for the presence of metamorphic fluids during the precipitation of ductilely deformed quartz veins. This requires the penetration during orogenesis of meteoric waters into and possibly below the brittle to ductile transition zone. © 2014 The Authors. 2014 English 0012821X 10.1016/j.epsl.2014.04.046 Earth and Planetary Science Letters 399 Elsevier 1-13 Ocean and Earth Science, National Oceanography Centre Southampton, University of Southampton, Southampton SO14 3ZH, United Kingdom; Department of Geology, University of Otago, Dunedin, New Zealand; GNS Science, Private Bag 1930, Dunedin 9054, New Zealand; S.U.E.R.C., Scottish Enterprise Technology Park, Rankine Avenue, East Kilbride, Glasgow G75 0QF, United Kingdom; Isoprime Ltd., Isoprime House, Earl Road, Cheadle Hulme, Cheadle SK8 6PT, United Kingdom Digital storage; Flow of fluids; Hydrogen; Isotopes; Metamorphic rocks; Mineralogy; Oxygen; Quartz, Alpine Faults; Fluid inclusion; Meteoric waters; Southern Alps; Stable isotopes, Deformation https://www.scopus.com/inward/record.uri?eid=2-s2.0-84900859302&doi=10.1016%2fj.epsl.2014.04.046&partnerID=40&md5=b54e2cf74ea7954995c70be679f3ef84 cited By 79 C.D. Menzies D.A.H. Teagle D. Craw S.C. Cox A.J. Boyce C.D. Barrie S. Roberts incollection webb2014icdp 2014 SEG Technical Program Expanded Abstracts 2014 Society of Exploration Geophysicists 1736--1741 Susan J Webb* Lewis D Ashwal Robert Trumbull Ilya Veksler article ELDERS20141 2014 0375-6505 https://doi.org/10.1016/j.geothermics.2013.08.012 Geothermics 49 1 https://www.sciencedirect.com/science/article/pii/S0375650513000746 Iceland Deep Drilling Project:The first well, IDDP-1, drilled into Magma Wilfred A. Elders Guðmundur Ó. Friðleifsson Bjarni Pálsson article ARMANNSSON201466 The Leirbotnar field, where IDDP-01 is situated consists of an upper liquid dominated zone to 1000–1400m depth, 190–220°C, sulphate major anion, and a lower two phase zone, 300°C chloride main anion. The IDDP-01 fluid is dry steam, local origin, pH 3. The major anion is chloride (20–166mg/kg), probably of magmatic origin. The major metallic cations, Fe (5–100mg/kg), Cr (0–6mg/kg), Ni (0–5mg/kg) and Mn (0.1–0.8mg/kg) seem to be derived from the well casing and sampling equipment. The gas content is low (about 0.1%) and the gas is apparently not directly emitted from magma. 2014 0375-6505 https://doi.org/10.1016/j.geothermics.2013.08.005 Geothermics 49 66-75 IDDP, Krafla, Geochemistry, Acid well fluids https://www.sciencedirect.com/science/article/pii/S0375650513000618 Iceland Deep Drilling Project:The first well, IDDP-1, drilled into Magma Halldór Ármannsson Thráinn Fridriksson Gudmundur H. Gudfinnsson Magnús Ólafsson Finnbogi Óskarsson Dadi Thorbjörnsson article Bischoff2014107 Microbial permafrost communities play an important role in carbon cycling and greenhouse gas fluxes. Despite the importance of these processes, there is a lack of knowledge about how environmental and climatic changes affect the abundance and composition of microorganisms. Here, we investigated the changing distribution of permafrost microorganisms in response to climate and lake-level changes. The permafrost core was drilled at the near shore of Lake El'gygytgyn, Far East Russian Arctic, and a combined microbiological and lipid biomarker approach was applied. The lower part of the permafrost core, deposited under subaquatic conditions, contains only small amounts of microbial signals; total organic carbon (TOC) content is sparse. After exposure of the site to subaerial conditions during the Allerød, the abundance of Bacteria and Archaea started to increase and the lake-level change is especially evidenced by the relative proportion of archaeal biomarkers. This increase is supported by rising bacterial and archaeal 16S ribosomal ribonucleic acid (rRNA) gene copy numbers and significant amounts of TOC during the late Allerød. After a small decrease during the colder Younger Dryas, the TOC content and the microbial signals strongly increase during the Holocene, presumably stimulated by pedogenesis. The occurrence of intact phospholipids indicates the presence of living microorganisms in these deposits. Our data suggest that methane formation is mainly expected for the subaerial interval, especially the Holocene where methanogens were identified by fingerprinting. This study emphasises the role of the uppermost permafrost deposits as a hotspot of carbon cycling in arctic environments, especially in the light of expected future global warming. © 2014 John Wiley & Sons, Ltd. 2014 English 10456740 10.1002/ppp.1807 Permafrost and Periglacial Processes 25 John Wiley and Sons Ltd 107-116 Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Research Unit Potsdam, Potsdam, Germany; GFZ German Research Centre for Geosciences, Section 4.3 Organic Geochemistry, Telegrafenberg, Potsdam, Germany; GFZ German Research Centre for Geosciences, Section 4.5 Geomicrobiology, Telegrafenberg, Potsdam, Germany; School of Civil Engineering and Geosciences, Newcastle University, Newcastle upon Tyne, United Kingdom 2 abundance; arctic environment; biomarker; carbon cycle; climate change; Holocene; lake level; methane; microbial community; microbiology; microorganism; pedogenesis; permafrost; phospholipid; RNA; total organic carbon; Younger Dryas, Arctic; Chukchi; Elgygytgyn Lake; Russian Federation, Archaea; Bacteria (microorganisms) https://www.scopus.com/inward/record.uri?eid=2-s2.0-84901920929&doi=10.1002%2fppp.1807&partnerID=40&md5=264deadfd6e8fe84913beb2bfd0d29cd cited By 9 J. Bischoff K. Mangelsdorf G. Schwamborn D. Wagner article Schmincke2014195 Fifteen Lateglacial to Holocene rhyolitic, dominantly primary tephra layers piston-cored and drilled (ICDP Paleovan drilling project) in western Lake Van (eastern Anatolia, Turkey) were precisely correlated to either of the two adjacent and active large volcanoes Nemrut and Süphan based on shard textures, mineralogy and mineral and glass compositions. The young peralkaline (comenditic to pantelleritic) primary rhyolitic Nemrut tephras are characterized by anorthoclase, hedenbergitic to augitic clinopyroxene, fayalitic olivine, minor quartz, and rare accessory chevkinite and zircon. Phenocrysts in subalkaline primary rhyolitic Süphan tephras are chiefly oligoclase-labradorite, with minor K-rich sanidine in some, biotite, amphibole, hypersthene, rare augitic clinopyroxene, relatively common allanite and rare zircon.Two contrasting explosive eruptive modes are distinguished from each other: episodic (Süphan) and periodic (Nemrut). The Lateglacial Süphan tephra swarm covers a short time interval of ca. 338. years between ca. 13,078. vy BP and 12,740. vy BP, eruptions having occurred statistically every ca. 42. years with especially short intervals between V-11 (reworked) and V-14. Causes for the strongly episodic Süphan explosive behavior might include seismic triggering of a volcano-magma system unable to erupt explosively without the benefit of external triggering, as reflected in pervasive faulting preceding the Süphan tephra swarm. Seismic triggering may have caused the rise of more mafic ("trachyandesitic") parent magma, heating near-surface pockets of highly evolved magma - that might have formed silicic domes during this stage of volcano evolution - resulting in ascent and finally explosive fragmentation of magma essentially by external factors, probably significantly enhanced by magma-water/ice interaction.Explosive eruptions of the Nemrut volcano system, interpreted to be underlain by a large fractionating magma reservoir, follow a more periodic mode of (a) long-term relatively constant supply of parent magma, (b) evolution by low pressure crystal fractionation resulting in sporadic relatively low-volume eruption of trachytic and minor rhyolitic magmas, (c) evolution of a large magma reservoir to the point of highly explosive large-volume peralkaline rhyolitic Plinian eruptions at temporal intervals of ca. 20-40. ky, some accompanied by ignimbrites and inferred caldera collapse.A striking tephra gap between ca. 14. ka and ca. 30. ka, i.e. during glacial climate conditions, is postulated to be due to climate-forcing via lithosphere unloading following deglaciation. © 2014 Elsevier B.V. 2014 English 03770273 10.1016/j.jvolgeores.2014.08.015 Journal of Volcanology and Geothermal Research 285 Elsevier 195-213 GEOMAR Helmholtz Centre for Ocean Research Kiel, Wischhofstr. 1-3, Kiel, 24148, Germany Explosive activity; Lake vans; Tephra swarm; Tephrostratigraphy; Volcanic activities, climate forcing; earthquake trigger; explosive volcanism; Holocene; late glacial; stratigraphy; tephra; volcanic eruption, Anatolia; Bitlis; Lake Van; Nemrut; Turkey https://www.scopus.com/inward/record.uri?eid=2-s2.0-84907818833&doi=10.1016%2fj.jvolgeores.2014.08.015&partnerID=40&md5=786e9e367748740c3ccbbb33e85460e1 cited By 26 H.-U. Schmincke M. Sumita article Coble2014956 Along the central segment of the San Andreas Fault (SAF) near Parkfield, California, displacement occurs by a combination of aseismic creep and micro-earthquake slip. To constrain the strength and parametrize a constitutive relation for the creeping behaviour of the central segment of the SAF, we conducted friction experiments on clay-rich gouge retrieved by coring the Central Deforming Zone (CDZ) of the SAF at 2.7 km vertical depth. The gouge was flaked rather than powdered to preserve the natural scaly microfabric, and formed into 2-mm-thick layers that were sheared using a triaxial deformation apparatus. Experiments were conducted at in situ effective normal stress (100 MPa), pore pressure (25 MPa) and temperature (80-120 °C) conditions using brine pore fluid with the ionic composition of the in situ formation fluid. Velocity-stepping (0.006-0.6 μm s-1) and temperature-stepping experiments were conducted on brine-saturated gouge, and slide-hold-slide experiments were conducted on brine-saturated and room-dry gouge. Results are used to quantify the effects of rate, state, temperature and pore fluid on the strength of the CDZ gouge. We find that the gouge is extremely weak (μ &lt; 0.13) and rate-strengthening, consistent with findings of previous studies on the CDZ gouge. We also find that, in a rate and state friction framework, slip history has a negligible effect on strength (b ≈ 0) under both saturated and dry conditions. The CDZ gouge is temperature-weakening from 80 to 120 °C and weakens 17 per cent when saturated with brine compared to room-dry conditions. Employing the laboratory-derived friction constitutive parameters, and including the temperature weakening and the strain-rate strengthening effects, we determine an approximate in situ friction coefficient of μ ≈ 0.11. For μ ≈ 0.11, aseismic creep under normal pore fluid conditions is permitted for angles up to 79° between the maximum horizontal stress and the plane of the SAF, consistent with nearby stress orientation measurements., Copy; The Authors 2014. 2014 English 0956540X 10.1093/gji/ggu306 Geophysical Journal International 199 Oxford University Press 956-967 Center for Tectonophysics, Department of Geology and Geophysics, Texas A and M University, College Station, TX 77843-3115, United States; Institute of Earthquake and Volcano Geology, Geological Survey of Japan, Ibabraki, Japan 2 Creep; Geomechanics; Strain rate; Strike-slip faults, Constitutive parameters; Constitutive relations; Creep and deformations; Effective normal stress; Fault zone; Friction coefficients; Rate and state friction; Strain-rate strengthening effects, Friction, creep; deformation; displacement; fault gouge; fault zone; friction; geomechanics; rheology; San Andreas Fault, California; San Andreas; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-84924987089&doi=10.1093%2fgji%2fggu306&partnerID=40&md5=0ff2c059d6f16d3f9e40a5d80650d1cc cited By 22 C.G. Coble M.E. French F.M. Chester J.S. Chester H. Kitajima article Minyuk2014467 Geochemical analyses were performed on sediments recovered by deep drilling at Lake El'gygytgyn in central Chukotka, northeastern Russia (67 30' N; 172 05' E). Major and rare element concentrations were determined using X-ray fluorescence spectroscopy (XRF) on the &lt; 250 μm fraction from 617 samples dated to ca. 440 and 125 ka, which approximates marine isotope stages (MIS) 11 to 6. The inorganic geochemistry indicates significant variations in elemental composition between glaciations and interglaciations. Interglacial sediments are characterized by high contents of SiO2, Na2O, CaO, K 2O, and Sr and are depleted in Al2O3, Fe2O 3, TiO2, and MgO. An extreme SiO2 enrichment during MIS 11.3 and 9.3 was caused by an enhanced flux of biogenic silica (BSi). The geochemical structure of MIS 11 shows similar characteristics as seen in MIS 11 records from Lake Baikal (southeastern Siberia) and Antarctic ice cores, thereby arguing for the influence of global forcings on these records. High sediment content of TiO2, Fe2O3, MgO, Al 2O3, LOI, Ni, Cr, and Zr typifies glacial stages, with the most marked increases during MIS 7.4 and 6.6. Reducing conditions during glacial times are indicated by peaks in the Fe2O3 content and coinciding low Fe2O3/MnO ratios. This conclusion also is supported by P2O5 and MnO enrichment, indicating an increased abundance of authigenic, fine-grained vivianite. Elemental ratios (CIA, CIW, PIA, and Rb/Sr) indicate that glacial sediments are depleted in mobile elements, like Na, Ca, K and Sr. This depletion was caused by changes in the sedimentation regime and thus reflects environmental changes. © 2014 Author(s). 2014 English 18149324 10.5194/cp-10-467-2014 Climate of the Past 10 European Geosciences Union 467-485 North-East Interdisciplinary Scientific Research Institute, Far East Branch, Russian Academy of Science, Magadan, Russian Federation; University of Cologne, Institute for Geology and Mineralogy, Cologne, Germany 2 chemical composition; concentration (composition); data set; drilling; environmental change; glacial deposit; glaciation; interglacial; lacustrine deposit; marine isotope stage; sediment chemistry; sedimentation, Chukchi; Elgygytgyn Lake; Lake Baikal; Russian Federation; Siberia https://www.scopus.com/inward/record.uri?eid=2-s2.0-84896109828&doi=10.5194%2fcp-10-467-2014&partnerID=40&md5=fd17328c584144539f90a952de7e67f2 cited By 42 P.S. Minyuk V.Y. Borkhodoev V. Wennrich article SCHIFFMAN201442 A rhyolite magma body within the Krafla geothermal system that was encountered at a depth of 2.1km during drilling of the IDDP-1 borehole is producing high temperature metamorphism within a conductive boundary layer (CBL) in adjacent host rocks. Cuttings recovered during drilling within a few meters of the intrusive contact in IDDP-1 are mainly comprised of granoblastic hornfelses, the rock type which confirms the presence of the CBL at the base of the IDDP-1 bore hole. The two pyroxenes in these hornfelses record temperatures that are in the range of 800–950°C. The minimum heat flow across the CBL is 23Wm−2. Country rocks at distances beyond 30m of the intrusive contact are essentially unaltered, implying that they have been emplaced very recently and/or as yet unaffected by hydrothermal fluid flow. 2014 0375-6505 https://doi.org/10.1016/j.geothermics.2012.11.002 Geothermics 49 42-48 Krafla, IDDP-1, Geothermal, Contact metamorphism https://www.sciencedirect.com/science/article/pii/S0375650512000673 Iceland Deep Drilling Project:The first well, IDDP-1, drilled into Magma Peter Schiffman Robert A. Zierenberg Anette K. Mortensen Guðmundur Ó. Friðleifsson Wilfred A. Elders article cp-10-467-2014 2014 10.5194/cp-10-467-2014 Climate of the Past 10 467-485 2 https://cp.copernicus.org/articles/10/467/2014/ P. S. Minyuk V. Y. Borkhodoev V. Wennrich article Puchtel2014394 Article 2014 10.1016/j.gca.2013.10.013 Geochimica et Cosmochimica Acta 125 394 – 413 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84888085933&doi=10.1016%2fj.gca.2013.10.013&partnerID=40&md5=f701a8ca3a198094fd1826f10b16752d Cited by: 83 Igor S. Puchtel Richard J. Walker Mathieu Touboul Euan G. Nisbet Gary R. Byerly article Roelofse2014bushveld 2014 Geobulletin 57 17--18 4 F Roelofse article Fischer20141 Earthquake swarms and high CO2 flow of mantle origin are the characteristic features of West Bohemia/Vogtland (Central Europe). At present, the highest concentration of earthquake activity and CO2 degassing occurs in the area of the Cheb Basin at the intersection of the Eger Rift and Regensburg-Leipzig-Rostock Zone with three Quaternary active volcanoes. We review about 140 studies on structure, tectonics, volcanism, seismicity, earthquake source, triggering mechanisms, and gas-isotope geochemistry focused on the earthquake swarms from this area with the aim to build a complex image of the ongoing processes and find a possible link between activity of the mantle-derived fluids and the earthquake swarms. The so far unpublished data on the 2011 swarm and little known data on the 1824 swarm are presented, as well, showing that earthquake swarms activate a complex fault system and display long-term migration that differs from the occurrence of CO2 escapes. The activity of individual swarms is consistent with models involving high-pressure fluids; the isotopic signature of the rising gas proves its origin at depths below the hypocenters. We show that the earthquake swarms and degassing of CO2 of magmatic origin represent common result of the geodynamic activity of the area. Nevertheless, current knowledge does not preclude processes other than fluid-induced failure in triggering swarm seismicity. © 2013 Elsevier B.V. Review 2014 English 00401951 10.1016/j.tecto.2013.11.001 Tectonophysics 611 1 – 27 Bohemia; Cheb Basin; Czech Republic; Germany; Karlovarsky; Vogtland; Carbon dioxide; Degassing; Exploratory geochemistry; Fluids; Geodynamics; Isotopes; Complex fault system; Earthquake swarms; Earthquake triggering; High-pressure fluids; Isotopic signatures; Triggering mechanism; Vogtland; West Bohemia; carbon dioxide; degassing; earthquake hypocenter; earthquake swarm; earthquake trigger; geochemistry; geodynamics; seismic source; seismicity; seismotectonics; trigger mechanism; volcanism; Earthquakes https://www.scopus.com/inward/record.uri?eid=2-s2.0-84891556616&doi=10.1016%2fj.tecto.2013.11.001&partnerID=40&md5=e03105e5ecd2e1dfe20493a49dc73fdd Cited by: 146 T. Fischer J. Horálek P. Hrubcová V. Vavryčuk K. Bräuer H. Kämpf article Wagner2014261 The 74 (75) ka Toba eruption in Sumatra, Indonesia, is considered to be one of the largest volcanic events during the Quaternary. Tephra from the Toba eruption has been found in many terrestrial and marine sedimentary deposits, and acidity peaks related to the eruption have been used to synchronize ice core records from Greenland and Antarctica. Seismic profiles and sedimentological data from Lake Prespa on the Balkan Peninsula, SE Europe, indicate a lake level lowstand at 73.6 ± 7.7 ka based on ESR dating of shells. Tephrostratigraphy, radiocarbon dating and tuning of the total organic carbon content with the NGRIP isotope record, corroborate that the lake level lowstand was a short-term event superimposed on the general cooling trend at the end of MIS 5, most likely at the onset of the Greenland Stadial GS-20. Acknowledging that tectonic events or karst processes could have triggered this lake level lowstand, the chronological correspondence between the lowstand and the Toba eruption is intriguing. Therefore a Toba-driven short-term shift to aridity in the Balkan region, leading to lake level changes and triggering spatial expansion events in one of the lake's most abundant benthic species, the carino mussel Dreissena presbensis, cannot be excluded. © Author(s) 2014. Article 2014 English 18149324 10.5194/cp-10-261-2014 Climate of the Past 10 Copernicus GmbH 261 – 267 1 Arctic; Greater Sunda Islands; Greenland; Indonesia; Lake Mikri Prespa; Sumatra; Sunda Isles; Dreissena; benthos; bivalve; data set; dating method; ice core; karst; Quaternary; radiocarbon dating; sedimentology; tephrochronology; volcanic eruption https://www.scopus.com/inward/record.uri?eid=2-s2.0-84925504593&doi=10.5194%2fcp-10-261-2014&partnerID=40&md5=121e0be6e18684958b932bacf84261cf Cited by: 7; All Open Access, Gold Open Access, Green Open Access B. Wagner M.J. Leng T. Wilke A. Böhm K. Panagiotopoulos H. Vogel J.H. Lacey G. Zanchetta R. Sulpizio article Albrecht2014163 Species invasions into ancient lakes are an important but little understood phenomenon. At ancient Lake Ohrid, a systematic assessment of invasive mollusc species using morphological and genetic data was conducted from 2003 to 2012. Two globally invasive gastropod species, Physa acuta and Ferrissia fragilis, have recently been discovered at 4 out of 386 sites. These sites are anthropogenically impacted. The invasive species co-occur with endemics. Phylogenetic analyses of populations from native and invaded ranges of both species confirmed their identities and provided insights into their invasion histories. Accordingly, P. acuta is genetically more diverse than F. fragilis. Both species are currently present in a considerable number of lakes on the Balkan Peninsula. Possible future trends in Lake Ohrid and the Balkans are discussed and further spread of both species is likely. Given the ongoing environmental change in Lake Ohrid, the number of observations of non-indigenous or other widespread species will probably rise in the coming years and such species and their impact on native species should be carefully monitored. Moreover, ancient lakes with recurrent invasions of alien species might serve as interesting model systems for the study of important topics of invasion biology. © 2013, Springer Science+Business Media Dordrecht. Article 2014 English 00188158 10.1007/s10750-013-1724-1 Hydrobiologia 739 Kluwer Academic Publishers 163 – 174 1 Lake Ohrid; Ferrissia fragilis; Ferrissia wautieri; Gastropoda; Physa acuta; coexistence; endemism; gastropod; identification key; introduced species; invasive species; lake ecosystem; phylogenetics; species diversity https://www.scopus.com/inward/record.uri?eid=2-s2.0-84907545253&doi=10.1007%2fs10750-013-1724-1&partnerID=40&md5=77501c34d3941bf348f6ff9f9fcead12 Cited by: 29 Christian Albrecht Kirstin Föller Catharina Clewing Torsten Hauffe Thomas Wilke article Carpenter201445 We report on laboratory measurements of permeability and elastic wavespeed for a suite of samples obtained by drilling across the active Alpine Fault on the South Island of New Zealand, as part of the first phase of the Deep Fault Drilling Project (DFDP-1). We find that clay-rich cataclasite and principal slip zone (PSZ) samples exhibit low permeabilities (≤10-18m2), and that the permeability of hanging-wall cataclasites increases (from c. 10-18 m2 to 10-15 m2) with distance from the fault. Additionally, the PSZ exhibits a markedly lower P-wave velocity and Young's modulus relative to the wall rocks. Our laboratory data are in good agreement with in situ wireline logging measurements and are consistent with the identification of an alteration zone surrounding the PSZ defined by observations of core samples. The properties of this zone and the low permeability of the PSZ likely govern transient hydrologic processes during earthquake slip, including thermal pressurization and dilatancy strengthening. © 2013 Elsevier B.V. 2014 English 0012821X 10.1016/j.epsl.2013.12.023 Earth and Planetary Science Letters 390 45-51 Istituto Nazionale di Geofisica e Vulcanologia, Rome 1 Section, Via di Vigna Murata, 605, Rome 00143, Italy; Department of Geosciences, Center for Geomechanics, Geofluids and Geohazards, The Pennsylvania State University, 534 Deike Building, University Park, PA 16802, United States; Active Fault and Earthquake Research Center, National Institute of Advanced Industrial Science and Technology, AIST Central 7, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8567, Japan; GNS Science, PO Box 30368, Lower Hutt 5040, New Zealand; School of Geography, Environment and Earth Sciences, Victoria University of Wellington, PO Box 600, Wellington 6140, New Zealand; Geology Department, University of Otago, PO Box 56, Dunedin 9054, New Zealand Alpine Faults; Drilling projects; Fault mechanics; Hydrologic process; Laboratory measurements; Low permeability; Petrophysics; Thermal pressurization, Elastic moduli; Mechanical permeability; Research laboratories; Wave propagation, Acoustic properties, acoustic property; active fault; core analysis; drilling; fault zone; hydraulic property; permeability; well logging, Alpine Fault Zone; New Zealand; South Island https://www.scopus.com/inward/record.uri?eid=2-s2.0-84892505514&doi=10.1016%2fj.epsl.2013.12.023&partnerID=40&md5=098cf8c2dcf2108fac4eff4f203e4e95 cited By 48 B.M. Carpenter H. Kitajima R. Sutherland J. Townend V.G. Toy D.M. Saffer article Vuillemin2014285 Article 2014 10.1080/01490451.2013.824050 Geomicrobiology Journal 31 285 – 298 4 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84894386725&doi=10.1080%2f01490451.2013.824050&partnerID=40&md5=902a67e02c2ab4433f23b26c1973bbcd Cited by: 9; All Open Access, Green Open Access A. Vuillemin D. Ariztegui G. Nobbe C.J. Schubert article ASMUNDSSON201490 During the early years of the Iceland Deep Drilling Project (IDDP), development of three distinctive technological and scientific approaches were formalised and then carried out until 2010 within a European funded project called HiTI (high temperature instruments for supercritical geothermal reservoir characterisation and exploitation). These approaches were: (1) development of several downhole instruments allowing them to function up to 300°C and 400°C, (2) identification of two new Na/Li cation ratio geothermometric relationships valid at very high temperature, (3) tracer testing with high temperature tolerant organic isomers and finally and (4) basalt rock deformation and petrophysical properties laboratory investigations at high temperature and pressure conditions. 2014 0375-6505 https://doi.org/10.1016/j.geothermics.2013.07.008 Geothermics 49 90-98 High temperature, Supercritical, Downhole, Geothermometers, Televiewer, Basalt experiments https://www.sciencedirect.com/science/article/pii/S0375650513000564 Iceland Deep Drilling Project:The first well, IDDP-1, drilled into Magma Ragnar Ásmundsson Bernard Sanjuan Jan Henninges Jean-Luc Deltombe Nigel Halladay François Lebert Alain Gadalia Romain Millot Benoit Gibert Marie Violay Thomas Reinsch Jean-Marc Naisse Pierre Azaïs David Mainprice Costas Karytsas Colin Johnston article Wagreich2014115 For many years Eduard Suess dealt with the phenomenon of displaced shorelines and the search for explanations for their genesis and the controlling factors. In the year 1888 Suess introduced the term eustatic movements referring to the global synchroneity of marker events in marine successions of the Earth history. Since the times of Suess, rapid scientific progress has considerably widened our understanding of the processes involved in changing sea levels. Eustasy now describes global sea-level changes that play a major role in controlling the development, structure and distribution of marine sedimentary successions. Relative (regional and local) and global (eustatic) sea-level fluctuations are controlled by a variety of endogenic and exogenic processes. Mantle convection and resulting gravity anomalies and tectonism, and climate changes are the main drivers, and apply at different temporal and spatial scales. The long-term sea-level record, i.e. 1st to 2nd order cycles and stratigraphic sequences, occurring over millions to tens of millions of years, is mainly controlled by the internal dynamic history of the Earth, e.g., the changing rates of ocean crust production. Short-term eustatic sea-level changes during ice house phases of Earth's climate are clearly controlled by waxing and waning of continental ice sheets. However, significant short-term, i.e. 10s kyr to a few Myr (3rd to 4th order cycles), sea-level changes during greenhouse episodes of Earth history are still enigmatic. Such cycles are often explained by the presence of ephemeral ice sheets even during the hottest greenhouse phases ("hothouse periods") of the Phanerozoic climate history such as the mid-Cretaceous. We argue that the effect of groundwater storage and release on sea-level change, particularly important during ice-free greenhousephases, has been and is widely underestimated in its order of magnitude. It is considered to constitute a water volume that is about equivalent to today's ice volume, thus corresponding to a potential sea-level change of up to ca. 50 m applying isostatic adjustment. Groundwater storage, including both freshwater and saline pore waters, strongly exceeds lake and river storage capacities. We introduce the term "limno-eustatic" to describe the effect of water volumes that are bound to groundwater and lake storage on sea-level fluctuations and cycles during major greenhouse phases of Earth history. Based on these terms the dimension of purely ice-driven glacio-eustatic processes can be better differentiated. The limno-eustatic hypothesis may be testable given high-resolution stratigraphic correlations between marine and continental lake archives during supposed ice-free periods of Earth history. Lake-level and sea-level fluctuations should be in an out of phase relation, i.e. a major marine sea-level lowstand should correspond to a lake-level highstand, and vice versa. Preliminary tests using selected stratigraphic levels of the Late Cretaceous record of the long-lived lacustrine Songliao basin in China indicate such an outof- phase relation, and thus support the limno-eustatic hypothesis as a mechanism to explain significant short-term sea-level fluctuations during greenhouse climate phases. 2014 English 02517493 Austrian Journal of Earth Sciences 107 Austrian Geological Society 115-131 Department of Geodynamics and Sedimentology, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria 1 Cretaceous; eustacy; geodynamics; geological record; isostasy; limnology; mantle convection; paleoclimate; sedimentary structure; sequence stratigraphy; spatiotemporal analysis; stratigraphic correlation; tectonic setting, China; Songliao Basin https://www.scopus.com/inward/record.uri?eid=2-s2.0-84903780882&partnerID=40&md5=bebbe1da1494e36c712c06f43b30698e cited By 68 M. Wagreich R. Lein B. Sames article ELDERS2014111 Drilling deeper in high-temperature geothermal systems by the IDDP is aimed at increasing the power output of shallower high-temperature geothermal fields by an order of magnitude without increasing their environmental footprints. The main thrust of the IDDP is to develop deep supercritical systems, but an unexpected encounter with a shallow body of magma demonstrated that very high power outputs are also possible from the contact zone of an intrusion. In the future it may be feasible to produce energy directly from magma. Favorable environments to implement these concepts are likely worldwide wherever active volcanoes and young volcanic rocks occur. 2014 0375-6505 https://doi.org/10.1016/j.geothermics.2013.05.001 Geothermics 49 111-118 Magma energy, Supercritical geothermal energy, Krafla Iceland https://www.sciencedirect.com/science/article/pii/S0375650513000382 Iceland Deep Drilling Project:The first well, IDDP-1, drilled into Magma W.A. Elders G.Ó. Friðleifsson A. Albertsson article Russell20145100 The Indo-Pacific warm pool houses the largest zone of deep atmospheric convection on Earth and plays a critical role in global climate variations. Despite the region's importance, changes in Indo-Pacific hydroclimate on orbital timescales remain poorly constrained. Here we present high-resolution geochemical records of surface runoff and vegetation from sediment cores fromLake Towuti, on the island of Sulawesi in central Indonesia, that continuously span the past 60,000 y.We show that wet conditions and rainforest ecosystems on Sulawesi present during marine isotope stage 3 (MIS3) and the Holocene were interrupted by severe drying between ∼33,000 and 16,000 y B.P. when Northern Hemisphere ice sheets expanded and global temperatures cooled. Our record reveals little direct influence of precessional orbital forcing on regional climate, and the similarity between MIS3 and Holocene climates observed in Lake Towuti suggests that exposure of the Sunda Shelf has a weaker influence on regional hydroclimate and terrestrial ecosystems than suggested previously. We infer that hydrological variability in this part of Indonesia varies strongly in response to high-latitude climate forcing, likely through reorganizations of the monsoons and the position of the intertropical convergence zone. These findings suggest an important role for the tropical western Pacific in amplifying glacial-interglacial climate variability. Article 2014 English 00278424 10.1073/pnas.1402373111 Proceedings of the National Academy of Sciences of the United States of America 111 National Academy of Sciences 5100 – 5105 14 runoff; titanium; article; canopy; climate; climate change; ecosystem; geochemistry; glacial interglacial variability; glacial period; Holocene; hydroclimate; hydrology; ice sheet; Indonesia; interglacial; lake; marine isotope stage 3; Northern Hemisphere; paleoclimate; precipitation; priority journal; sea surface temperature; sediment; stratigraphy; tropical rain forest; vegetation https://www.scopus.com/inward/record.uri?eid=2-s2.0-84898053681&doi=10.1073%2fpnas.1402373111&partnerID=40&md5=15e48141ebdbc687d0dde5a656ca8b9a Cited by: 107; All Open Access, Bronze Open Access, Green Open Access James M. Russell Hendrik Vogel Bronwen L. Konecky Satria Bijaksana Yongsong Huang Nigel Wattrus Kassandra Costa John W. King article Shervais201485 The Yellowstone supervolcano erupted roughly 640,000 years ago, covering much of North America in a thick coat of ash. Material ejected from the volcano devastated the surrounding area, and particles injected into the atmosphere changed the Earth's climate. Over the past 18 million years the Yellowstone hot spot has powered a series of similar eruptions. In southern Idaho, the 640-kilometer-long Snake River Plain traces the path of the Yellowstone hot spot over this period. ©2014. American Geophysical Union. All Rights Reserved. 2014 English 00963941 10.1002/2014EO100001 Eos 95 American Geophysical Union 85-86 Utah State University, Logan, United States; University of Alberta, Edmonton, Canada; Brigham Young University, Provo, UT, United States; University of South Carolina, Columbia, United States 10 ash; climate change; drilling; hot spot; mantle plume; volcanic eruption; volcanic ash, Idaho; Snake River Plain; United States; Yellowstone Volcanic Plateau https://www.scopus.com/inward/record.uri?eid=2-s2.0-84899115855&doi=10.1002%2f2014EO100001&partnerID=40&md5=e892ceab8c63c614b7ac8379ea96fbc7 cited By 6 J.W. Shervais J.P. Evans E.H. Christiansen A. Prokopenko article PALSSON201423 The first well of three proposed by the Iceland Deep Drilling Project (IDDP) was drilled in the Krafla Geothermal Field in 2008–2009 by Landsvirkjun, the National Power Company of Iceland. The well was designed to reach supercritical conditions at 4500m, temperatures above 374°C and pressures above 22MPa. Drilling progress was as planned down to around 2000m when drilling became quite challenging, including becoming stuck at 2094 and 2095m depth, followed by twist offs and subsequent side tracking. Finally, drilling came to an end at 2096m depth in the third leg when cuttings of fresh glass indicated the presence of a magma body at the bottom. As the well had such a rigorous well design, the steering committee of the IDDP decided to complete and flow test the well, rather than abandoning it. The well was very powerful and the project has proved to be a valuable experience for drilling supercritical wells in the future and what happens when magma is encountered. Most importantly, it has been proven that it is possible to drill and complete a well in a very hot zone and produce fluid from an environment near a magma body. If sustained long term production proves possible, the drilling of well IDDP-1 will mark a new era in power production in Krafla. 2014 0375-6505 https://doi.org/10.1016/j.geothermics.2013.08.010 Geothermics 49 23-30 Iceland Deep Drilling Project, Drilling, Magma, Superheat https://www.sciencedirect.com/science/article/pii/S0375650513000722 Iceland Deep Drilling Project:The first well, IDDP-1, drilled into Magma B. Pálsson S. Hólmgeirsson Á. Guðmundsson H.Á. Bóasson K. Ingason H. Sverrisson S. Thórhallsson article Kwiecien201442 A well-dated suite of Lake Van climate-proxy data covering the last 360ka documents environmental changes over 4 glacial/interglacial cycles in Eastern Anatolia, Turkey. The picture of cold and dry glacials and warm and wet interglacials emerging from pollen, organic carbon, authigenic carbonate content, elemental profiling by XRF and lithological analyses is inconsistent with classical interpretation of oxygen isotopic composition of carbonates pointing to a more complex pattern in Lake Van region. Detailed analysis of glacial terminations allows for the constraining of a depositional model explaining different patterns observed in all the proxies. We hypothesize that variations in relative contribution of rainfall, snowmelt and glacier meltwater recharging the basin have a very important role for all sedimentary processes in Lake Van. Lake level of glacial Lake Van, predominantly fed by snowmelt, was low, the water column was oxic, and carbonates precipitating in the epilimnion recorded the light isotopic signature of inflow. During terminations, increasing rainfall and significant supply of mountain glaciers' meltwater contributed to lake level rise. Increased rainfall enhanced density gradients in the water column, and hindered mixing leading to development of bottom-water anoxia. Carbonates precipitating during terminations show large fluctuations in their isotopic composition. Full interglacial conditions in Lake Van are characterized by high or slowly falling lake level. Rainfall and snowmelt feed the lake but due tore-established mixing, the isotopic composition of authigenic carbonates is heavier and closer to that of evaporation-influenced lake water than that of runoff representing snowmelt and atmospheric precipitation. © 2014 Elsevier Ltd. 2014 English 02773791 10.1016/j.quascirev.2014.07.001 Quaternary Science Reviews 104 Elsevier Ltd 42-52 ETH Zurich, Climate Geology, Sonneggstrasse 5, Zurich, 8092, Switzerland; Eawag Dubendorf, Ueberlandstrasse 130, Duebendorf, 8600, Switzerland; Steinmann Institute of Geology, Mineralogy and Paleontology, Bonn University, Nussallee 8, Bonn, 53115, Germany; Institute of Geological Sciences and Oeschger Centre for Climate Change Research, University of Bern, Baltzerstrasse 1-3, Bern, 3012, Switzerland Carbonates; Glacial geology; Isotopes; Lithology; Mixing; Organic carbon; Rain; Snow melting systems, Eastern Mediterranean; Glacial/interglacial cycle; Lake vans; Multi proxies; Oxygen isotopes; Termination, Lakes, anoxia; carbonate; epilimnion; glacial environment; glacial-interglacial cycle; isotopic composition; lithology; numerical model; oxygen isotope; paleoclimate; proxy climate record; rainfall; runoff; snowmelt, Anatolia; Lake Van; Mediterranean Sea; Mediterranean Sea (East); Turkey https://www.scopus.com/inward/record.uri?eid=2-s2.0-84909598325&doi=10.1016%2fj.quascirev.2014.07.001&partnerID=40&md5=0d12c4a591b3dde8afac1e774afc753b cited By 45 O. Kwiecien M. Stockhecke N. Pickarski G. Heumann T. Litt M. Sturm F. Anselmetti R. Kipfer G.H. Haug article Lorenschat2014524 We carried out an intensive sampling survey in ancient Lake Ohrid (Macedonia/Albania), covering all seasons, to determine total species number, relative species abundances and spatial distribution of Ostracoda. We identified 32 living species that belong to seven families (Candonidae, Ilyocyprididae, Cyprididae, Leptocytheridae, Limnocytheridae, Cytherideidae, and Darwinulidae) and 15 genera (Candona, Fabaeformiscandona, Candonopsis, Cypria, Cyclocypris, Ilyocypris, Eucypris, Prionocypris, Bradleystrandesia, Herpetocypris, Dolerocypris, Amnicythere, Paralimnocythere, Cytherissa, and Darwinula). Six additional species were identified from empty carapaces and valves. Dominant families in Lake Ohrid were Candonidae and Limnocytheridae, representing 53% and 16% of all species, respectively. Prevalence of species flocks in these two families confirms the "young" ancient status of the lake. Amnicythere displays a preference for oligo-haline to meso-haline waters, but some species are found in saline environments, which suggests Lake Ohrid has a marine history. Recent studies, however, indicate fluvial/glaciofluvial deposition at the onset of Lake Ohrid sedimentation. Candona is the most diverse genus in Lake Ohrid, represented by 12 living species. Paralimnocythere is represented by five living species and all other genera are represented by one or two species. Reports of Candona bimucronata, Ilyocypris bradyi, Eucypris virens, Eucypris sp., Prionocypris zenkeri, Bradleystrandesia reticulate, Herpetocypris sp. 2, and Dolerocypris sinensis are firsts for this lake. Living ostracodes were collected at the maximum water depth (280 m) in the lake (Candona hadzistei, C. marginatoides, C. media, C. ovalis, C. vidua, Fabaeformiscandona krstici, Cypria lacustris, C. obliqua and Amnicythere karamani). Cypria lacustris was overall the most abundant species and Cypria obliqua displayed the highest abundance at 280 m water depth. Principal environmental variables that influence ostracode distributions in Lake Ohrid are water depth and conductivity. In general, species richness, diversity and evenness were greater in waters &#60;60 m deep, with highest values often found in the littoral zone, at depths &#60;30 m. Candonids, however, displayed highest diversity in the sublittoral (30-50 m) and profundal (50-280 m) zones. The most frequent species encountered are taxa endemic to the lake (14 living species), which have a wide depth range (≤280 m), and display higher abundance with greater water depth. Non-endemic species were rare, limited to water depths &#60;50 m, and were found mainly in the north part of the lake where anthropogenic pressure is high. Several cosmopolitan species were encountered for the first time, which suggests that these widespread species are new arrivals that may replace endemics as human impacts increase. © 2014 by the authors. Article 2014 English 14242818 10.3390/d6030524 Diversity 6 MDPI AG 524 – 550 3 Albania; Greece; Lake Ohrid; Macedonia [Greece]; Crustacea; Ostracoda; anthropogenic effect; biodiversity; endemism; human activity; intertidal environment; ostracod; spatial distribution; species diversity; species evenness; species richness; taxonomy; water depth https://www.scopus.com/inward/record.uri?eid=2-s2.0-84906900005&doi=10.3390%2fd6030524&partnerID=40&md5=54511cb54015635fff82bdbdc4ea5af6 Cited by: 15; All Open Access, Gold Open Access, Green Open Access Julia Lorenschat Liseth Pe´rez Alexander Correa-Metrio Mark Brenner Ullrich Bramann Antje Schwalb article Hahn2014349 During the lake deep drilling campaign PASADO in 2008, more than 500 m of lacustrine sediment was recovered from the maar lake Laguna Potrok Aike, Argentina. The major element composition was assessed at high resolution with an ITRAX X-ray fluorescence core scanner. The sharp boundary between a carbonate-bearing and a carbonate-free depositional system occurs at 13.5 cal. ka BP and marks the transition from glacial to Late Glacial sediments. Holocene and Late Glacial sediments can be distinguished by elements that are indicative of organic matter (Br, Cl) or calcite (Ca). Glacial sediments are characterized by elements that represent terrigenous clastic input (Fe, Ti, K, Si). Trace elements (Mn, Rb, V, Ni) accumulate with the bulk of lithogenic elements indicating frequent oxic conditions and rare diagenetic remobilization. Based on principal component analysis we interpret the scores of the first principle component as a summarizing indicator for climate-related variations of depositional conditions. During the Holocene climate changes mirror the total inorganic carbon profile, which was used as a proxy for lake-level reconstructions of the past 16 ka in previous studies. High scores in the first principle component probably reflect periods of increased chemical over mechanical weathering and developing soils and vegetation cover limiting sediment availability for erosional processes. These intervals often also show increases in total organic carbon values and total organic carbon/total nitrogen ratios, which are associated with periods of Antarctic warming in the last glacial. Geochemical variations of the clastic glacial sediments are explored by excluding carbonate-bearing sediments from principal component analysis. Although, in this lake, Ca is a purely clastic signal in carbonate-free sediments, it does not correlate with the bulk of indicators for terrigenous input. Instead Ca dominates a second principal component together with Sr. This component mainly distinguishes coarse grained layers from the remaining sediment. The main provenance of this coarse-grained material is suggested to be a basalt outcrop at the western shore. Low lake levels, high waves and flash-flood events may have increased the availability of basaltic sand during extremely cold, arid and windy conditions. High wind speeds and lack of vegetation may have facilitated the increased transport of coarse-grained material into the center of Laguna Potrok Aike. Decreases in the second principal component can be observed during Oxygen Isotope Stage 2 when increased dust input has been found in cores from Laguna Potrok Aike, the Southern Ocean and Antarctica. © 2014, Springer Science+Business Media Dordrecht. Article 2014 10.1007/s10933-014-9798-y Journal of Paleolimnology 52 349 – 366 4 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84921938721&doi=10.1007%2fs10933-014-9798-y&partnerID=40&md5=d61ecd5740a23ff28901aa0959dc8b86 Cited by: 22 Annette Hahn Pierre Kliem Markus Oehlerich Christian Ohlendorf Bernd Zolitschka article Pearson201413 We are currently developing a proposal for a new International Continental Scientific Drilling Program (ICDP) project to recover a stratigraphic and paleoclimatic record from the full succession of Eocene hemipelagic sediments that are now exposed on land in southern Tanzania. Funding for a workshop was provided by ICDP, and the project was advertised in the normal way. A group of about 30 delegates assembled in Dar-es-Salaam for 3 intensive days of discussion, project development, and proposal writing. The event was hosted by the Tanzania Petroleum Development Corporation (TPDC) and was attended by several geologists, geochemists, geophysicists, and micropaleontologists from TPDC and the University of Dar-es-Salaam. International delegates were from Canada, Germany, India, Ireland, Italy, the Netherlands, United Kingdom, and United States (and we also have project partners from Australia, Belgium, and Sweden who were not able to attend). Some of the scientists are veterans of previous scientific drilling in the area, but over half are new on the scene, mostly having been attracted by Tanzania's reputation for world-class paleoclimate archives. Here we outline the broad aims of the proposed drilling and give a flavor of the discussions and the way our proposal developed during the workshop. A video of the workshop with an introduction to the scientific goals and interviews of many of the participants is available at http://vimeo.com/107911777. 2014 English 18168957 10.5194/sd-18-13-2014 Scientific Drilling 18 Copernicus GmbH 13-17 School of Earth and Ocean Sciences, Cardiff University, Main Building, Park Place, Cardiff, CF10 3AT, United Kingdom; Tanzania Petroleum Development Corporation, Lumumba Street, Dar-es-Salaam, Tanzania Drilling; Energy resources, Continental scientific drillings; Hemipelagic sediments; Paleoclimatic record; Petroleum development; Project development; Scientific drilling; Southern Tanzania; Tropical climates, Stratigraphy https://www.scopus.com/inward/record.uri?eid=2-s2.0-84926312146&doi=10.5194%2fsd-18-13-2014&partnerID=40&md5=51db75ba69a25852351377560e03bb39 cited By 0 P.N. Pearson W. Hudson article Baumgarten201485 Lake Van (Turkey) is the 4th largest terminal lake in the world and is located at a key position for climatic reconstruction. The ICDP project 'PALEOVAN' is a deep-drilling campaign initiated in the summer of 2010 to enhance the understanding of paleoclimatic and paleoenvironmental conditions in the Middle East for a period of 550,000 years. Multiple coring of two sites (Northern Basin and Ahlat Ridge) at a water depth of up to 360m has been performed. The sedimentary record is mainly composed of clayey silts and tephra deposits that were supplied by four volcanic sources: 1) the Süphan volcano, located on the northern shore, 2) the Nemrut volcano, 15km west of the westernshore, 3) the Incekaya volcano, on the southwestern shore and 4) intralake eruptive centers. The dominant chemical composition of the volcanic sources is known from studies of land deposits.High-quality downhole logs have been acquired from both sites. To construct a continuous lithological profile, 180m of downhole logging data from the Ahlat Ridge have been analyzed by cluster analysis. To improve the differentiation of the sediments, two elemental intensity profiles from x-ray fluorescence core-scanning (calcium and zirconium) performed on the composite profile core material were added to the cluster analysis. Five cluster units were derived and transformed into three tephra and two clayey silt units. To compare the two clayey silt units with the composite profile from the visual core description (VCD) that showed 15 lithological units, the composite profile was classified into two major groups of lacustrine sediments: banded clayey silts (interpreted as glacial deposits) and laminated clayey silts (interpreted as interglacial deposits). Despite this simplification, no correlation between the two clayey silt units derived from cluster analysis and the banded and laminated clayey silts could be found. The following reasons are proposed: (a) the comparability of the datasets was limited by significant depth shifts of up to 2.5m between the composite profile based on the VCD and the downhole measurements in hole 2D of the Ahlat Ridge, (b) a correlation was difficult to ascertain from the vertical resolution of the downhole logging data and the extremely detailed core description in mm-scale, (c) mixed signals were obtained because of prevailing thin layers and intercalations of different lithotypes and (d) cluster analysis was difficult to perform because the contrast within the input data is too low (possibly background sedimentation) to distinguish between glacial and interglacial deposits. Tephra units are characterized by contrasting properties and differ mainly in their magnetic susceptibility, spectral gamma ray components (uranium, thorium and potassium) and XRF-intensities of calcium and zirconium. Tephra units have been linked to the dominant volcanic composition of the deposited tephra layers and partly to the volcanic sources. Depth trends are derived with prevailing basaltic deposits in the bottom part (128m-210m below lake floor) and are gradually outweighed by the highly differentiated (dacitic and rhyolitic/trachytic) products towards the top of the record. © 2014 Elsevier Ltd. 2014 English 02773791 10.1016/j.quascirev.2014.03.016 Quaternary Science Reviews 104 Elsevier Ltd 85-96 Leibniz Institute for Applied Geophysics (LIAG), Rock Physics and Borehole Geophysics, Stilleweg 2, Hannover, 30655, Germany Physical properties, Downholes; ICDP; Lake sediments; Paleoclimates; PALEOVAN; Quaternary; Tephra, Cluster analysis, basalt; chemical composition; clay; cluster analysis; depositional environment; facies; lacustrine deposit; paleoclimate; paleolimnology; physical property; Pleistocene; sediment core; sedimentation; silt; tephra; volcanic eruption; volcanogenic deposit; well logging, Lake Van; Turkey; Turkey https://www.scopus.com/inward/record.uri?eid=2-s2.0-84909585607&doi=10.1016%2fj.quascirev.2014.03.016&partnerID=40&md5=b8e3d209b32fd9d0a2033adedcf27532 cited By 10 H. Baumgarten T. Wonik O. Kwiecien conference Haldorsen20142288 The San Andreas Fault Observatory at Depth (SAFOD) is a deep borehole observatory constructed to investigate the source of recurring earthquakes at a specific location on the San Andreas Fault. Numerous geophysical datasets were acquired at the SAFOD site to characterize the subsurface environment. Among these, we collected three independent seismic datasets to characterize the local geologic structure. These datasets include VSP, drill-bit noise, and earthquake recordings. Initially, interferometric deconvolution was applied to the drill-bit noise using Schlumberger patented methods to determine the reference signal from rig-based receivers. Next, it was applied in a modified processing flow to determine the reference signal from downhole receivers. Finally, as a result of the application of the technique to earthquake data, we obtained high resolution imaging of the San Andreas Fault at depths exceeding 2.5 km. In conjunction with the other seismic datasets collected at the site, we interpret the complex system of faults and fractures to constitute a flower structure which is partially exposed at Middle Mountain northeast of the SAFOD site. © 2014 SEG. 2014 English 9781634394857 10523812 10.1190/segam2014-0013.1 SEG Technical Program Expanded Abstracts 33 Society of Exploration Geophysicists Birkelo B. 2288-2293 Read ASA, United States; Schlumberger PTS, United States; Miller Applied Science, United States Bits; Drills; Earthquakes; Infill drilling; Observatories; Seismic prospecting; Signal processing; Strike-slip faults, Downhole receivers; Earthquake recording; Fault delineations; Flower structures; Geologic structures; High-resolution imaging; San Andreas fault; Subsurface environment, Signal receivers https://www.scopus.com/inward/record.uri?eid=2-s2.0-85018459833&doi=10.1190%2fsegam2014-0013.1&partnerID=40&md5=3c9cd7a5a2741823c686fd9ffc9fe02d cited By 0 J.B.U. Haldorsen S. Taylor D.E. Miller article Janssen2014100 The microstructures, mineralogy and chemistry of representative samples collected from the cores of the San Andreas Fault drill hole (SAFOD) and the Taiwan Chelungpu-Fault Drilling project (TCDP) have been studied using optical microscopy, TEM, SEM, XRD and XRF analyses. SAFOD samples provide a transect across undeformed host rock, the fault damage zone and currently active deforming zones of the San Andreas Fault. TCDP samples are retrieved from the principal slip zone (PSZ) and from the surrounding damage zone of the Chelungpu Fault. Substantial differences exist in the clay mineralogy of SAFOD and TCDP fault gouge samples. Amorphous material has been observed in SAFOD as well as TCDP samples. In line with previous publications, we propose that melt, observed in TCDP black gouge samples, was produced by seismic slip (melt origin) whereas amorphous material in SAFOD samples was formed by comminution of grains (crush origin) rather than by melting. Dauphiné twins in quartz grains of SAFOD and TCDP samples may indicate high seismic stress. The differences in the crystallographic preferred orientation of calcite between SAFOD and TCDP samples are significant. Microstructures resulting from dissolution-precipitation processes were observed in both faults but are more frequently found in SAFOD samples than in TCDP fault rocks. As already described for many other fault zones clay-gouge fabrics are quite weak in SAFOD and TCDP samples. Clay-clast aggregates (CCAs), proposed to indicate frictional heating and thermal pressurization, occur in material taken from the PSZ of the Chelungpu Fault, as well as within and outside of the SAFOD deforming zones, indicating that these microstructures were formed over a wide range of slip rates. © 2014 Elsevier Ltd. 2014 English 01918141 10.1016/j.jsg.2014.04.004 Journal of Structural Geology 65 Elsevier Ltd 100-116 GeoForschungsZentrum Potsdam, Telegrafenberg, Potsdam 14473, Germany; Department of Earth and Planetary Science, University of California, Berkeley, CA 94720, United States; Department of Geosciences, National Taiwan University, P.O. Box 13-318, Roosevelt Road, Taipei 106, Taiwan Chemical analysis; Deformation; Grinding (comminution); Microstructure; Minerals; Quartz; Seismology; Strike-slip faults; Tectonics, CPO; EBSD; Fault rock; SAFOD; TCDP, Structural geology, active fault; amorphous medium; calcite; clay mineral; crystal structure; crystallography; deformation; fault gouge; faulting; host rock; melting; microstructure; quartz; San Andreas Fault; slip rate https://www.scopus.com/inward/record.uri?eid=2-s2.0-84900831848&doi=10.1016%2fj.jsg.2014.04.004&partnerID=40&md5=8e0d6271781b3ba26f38c38495db3d9a cited By 26 C. Janssen R. Wirth H.-R. Wenk L. Morales R. Naumann M. Kienast S.-R. Song G. Dresen article Boulton2014356 Principal slip zone gouges recovered during the Deep Fault Drilling Project (DFDP-1), Alpine Fault, New Zealand, were deformed in triaxial friction experiments at temperatures, T, of up to 350°C, effective normal stresses, σn′, of up to 156 MPa, and velocities between 0.01 and 3 μm/s. Chlorite/white mica-bearing DFDP-1A blue gouge, 90.62 m sample depth, is frictionally strong (friction coefficient, μ, 0.61-0.76) across all experimental conditions tested (T = 70-350°C, σn′ = 31.2-156 MPa); it undergoes a transition from positive to negative rate dependence as T increases past 210°C. The friction coefficient of smectite-bearing DFDP-1B brown gouge, 128.42 m sample depth, increases from 0.49 to 0.74 with increasing temperature and pressure (T = 70-210°C, σn′ = 31.2-93.6 MPa); the positive to negative rate dependence transition occurs as T increases past 140°C. These measurements indicate that, in the absence of elevated pore fluid pressures, DFDP-1 gouges are frictionally strong under conditions representative of the seismogenic crust. 2014 English 00948276 10.1002/2013GL058236 Geophysical Research Letters 41 American Geophysical Union 356-362 Department of Geological Sciences, University of Canterbury, Christchurch, New Zealand; U.S. Geological Survey, Menlo Park, CA, United States; Department of Geology, University of Otago, Dunedin, New Zealand; School of Geography, Environment and Earth Sciences, Victoria University of Wellington, Wellington, New Zealand; GNS Science, Lower Hutt, New Zealand 2 Friction; Mica deposits, Alpine Faults; Fault friction; Frictional stability; New zealand; Plate boundaries; strike-slip, Strike-slip faults, deep drilling; experimental study; fault zone; friction; pore pressure; stress field; temperature effect, Alpine Fault Zone; New Zealand; South Island https://www.scopus.com/inward/record.uri?eid=2-s2.0-84892971467&doi=10.1002%2f2013GL058236&partnerID=40&md5=92a667acc2bb41fed43860106d709d55 cited By 57 C. Boulton D.E. Moore D.A. Lockner V.G. Toy J. Townend R. Sutherland article Ikari20141 The Alpine Fault in southern New Zealand is a major plate-boundary fault zone that, according to various lines of evidence, may be nearing the end of its seismic cycle and approaching earthquake failure. In order to better characterize this fault and obtain a better understanding of its seismic potential, two pilot boreholes have been completed as part of a larger drilling project. Samples representative of the major lithologic subdivisions of the fault zone at shallow (~ 100. m) depths were recovered and investigated in laboratory friction experiments. We show here that materials from within and very near the principal slip zone (PSZ) tend to exhibit velocity strengthening frictional behavior, and restrengthen (heal) rapidly compared to samples of the wall rock recovered near the PSZ. Fluid saturation causes the PSZ to be noticeably weaker than the surrounding cataclasites (μ = 0.45), and eliminates the velocity-weakening behavior in these cataclasites that is observed in dry tests. Our results indicate that the PSZ has the ability to regain its strength in a manner required for repeated rupture, but its ability to nucleate a seismic event is limited by its velocity-strengthening nature. We suggest that seismogenic behavior at depth would require alteration of the PSZ material to become velocity weakening, or that earthquake nucleation occurs either within the wall rock or at the interface between the wall rock and the PSZ. Coseismic ruptures which propagate to the surface have been inferred for previous earthquakes on the Alpine Fault, and may be facilitated by the slightly weaker PSZ material and/or high rates of healing in the PSZ which support fault locking and eventual stress drops. © 2014 Elsevier B.V. 2014 English 00401951 10.1016/j.tecto.2014.05.005 Tectonophysics 630 Elsevier 1-8 MARUM, Center for Marine Environmental Sciences, University of Bremen, Germany; Istituto Nazionale di Geofisica e Vulcanologia, Rome, Italy; Department of Geosciences, The Pennsylvania State University, United States C Boreholes; Boring; Earthquakes; Friction; Interfaces (materials); Locks (fasteners); Seismology; Velocity, Alpine Faults; Earthquake nucleation; Friction experiments; Frictional behavior; Frictional strength; Scientific drilling; Seismicity; Velocity-weakening, Faulting, borehole; earthquake mechanism; earthquake rupture; failure mechanism; friction; lithology; plate boundary; saturation; seismicity, Alpine Fault Zone; New Zealand; South Island https://www.scopus.com/inward/record.uri?eid=2-s2.0-84920156105&doi=10.1016%2fj.tecto.2014.05.005&partnerID=40&md5=d419fe17e49dfcef847c9df0616b4eab cited By 19 M.J. Ikari B.M. Carpenter A.J. Kopf C. Marone conference Cannon2014425 The Eastern Snake River Plain (ESRP) is an area of high regional heat flux due the movement of the North American Plate over the Yellowstone Hotspot beginning ca. 16 Ma. Temperature gradients between 45-60 °C/km (up to double the global average) have been calculated from deep wells that penetrate the upper aquifer system (Blackwell 1989). Despite the high geothermal potential, thermal signatures from hot springs and wells are effectively masked by the rapid flow of cold groundwater through the highly permeable basalts of the Eastern Snake River Plain aquifer (ESRPA) (up to 500+ m thick). This preliminary study is part of an effort to more accurately predict temperatures of the ESRP deep thermal reservoir while accounting for the effects of the prolific cold water aquifer system above. This study combines the use of traditional geothermometry, mixing models, and a multicomponent equilibrium geothermometry (MEG) tool to investigate the geothermal potential of the ESRP. In March, 2014, a collaborative team including members of the University of Idaho, the Idaho National Laboratory, and the Lawrence Berkeley National Laboratory collected 14 thermal water samples from and adjacent to the Eastern Snake River Plain. The preliminary results of chemical analyses and geothermometry applied to these samples are presented herein. Copyright © (2014) by the Geothermal Resources Council All right reserved. 2014 English 9781634394673 01935933 Transactions - Geothermal Resources Council 38 Geothermal Resources Council 425-431 University of Idaho-Idaho Falls, Idaho Falls, ID, United States; Center for Advanced Energy Studies, Idaho Falls, ID, United States; Ldaho National Laboratory, Idaho Falls, ID, United States; Lawrence Berkeley National Laboratory, Berkeley, CA, United States Aquifers; Chemical analysis; Geochemistry; Geothermal fields; Geothermal prospecting; Geothermal springs; Groundwater; Groundwater geochemistry; Groundwater resources; Heat flux; Heat transfer; Hot springs; Rivers, Geothermal; Geothermometry; MEG; RTEst; Snake river plains, Geothermal energy https://www.scopus.com/inward/record.uri?eid=2-s2.0-84937839907&partnerID=40&md5=d09eed428716f56c292b5a3062633eac cited By 1 C. Cannon T. Wood G. Neupane T. McLing E. Mattson P. Dobson M. Conrad article Uddin201440 The Mallik gas hydrate deposit was found to consist of 3 distinct, highly concentrated, high quality zones of structure I hydrate with partial occupancy of 5.75-6.2. Earlier simulation studies focused on history matching the 6 days production test of the lower zone, assuming 100% hydrate occupancy. The focus of the current study is on a simulation comparison of the expected response of the three hydrate bearing zones (lower, middle and upper) of the Mallik well 2L-38 to a single vertical well depressurization test. Additionally, a revised history match of the bottom zone field test considering partial gas occupancy of the hydrate, and a further assessment of the kinetic dissociation model are studied. This study extends the previously developed model found to successfully represent the physical and thermodynamic mechanisms involved with hydrate dissociation in the Mallik field test.The simulation results indicate that hydrate production from the middle hydrate zone is feasible and attractive, while production from the upper zone is not, due to its low pressure/temperature condition. Generally speaking, all three zones showed a similar role of the bottom aquifer in determining the water and gas flows, and all three zones showed an upward gas migration block by different existing hydrate layers. This effect is contrary to gas production from conventional gas reservoirs and indicates that the use of horizontal wells in such reservoirs may not be attractive.This study has also explored the role of partial gas cavity occupancy in the lower zone production characteristics and a re-history match of the 6 days Mallik production test showed an improved match and some indication about partial occupancy close to 6.88. Finally an in-depth examination of a previously reported laboratory scale study of methane hydrate decomposition and some observations from even smaller scale molecular dynamics study gave exciting clues of how to further interpret and improve our kinetic gas hydrate model, to be used at multiple time and length scales. Such an improved model has been proposed and awaits further testing and matching of appropriate data. © 2014. 2014 English 18755100 10.1016/j.jngse.2014.07.027 Journal of Natural Gas Science and Engineering 21 Elsevier B.V. 40-63 Alberta Innovates - Technology Futures, Edmonton, AB T6N 1E4, Canada; Geological Survey of Canada, Natural Resources Canada, Sidney, BC V8L 4B2, Canada; Computer Modeling Group Ltd., Calgary, AB T2L 2A6, Canada Aquifers; Dissociation; Gas industry; Gases; Horizontal wells; Hydration; Molecular dynamics; Petroleum reservoirs, Depressurizations; Hydrate dissociation; Hydration number; Salinity; Simulation, Gas hydrates https://www.scopus.com/inward/record.uri?eid=2-s2.0-84906061751&doi=10.1016%2fj.jngse.2014.07.027&partnerID=40&md5=b1a7585369cda69488c84bc6152e3423 cited By 52 M. Uddin F. Wright S. Dallimore D. Coombe article 10.1130/GES00935.1 {Recent ocean-bottom geophysical surveys, dredging, and dives, which complement surface data and scientific drilling at the Island of Hawaii, document that evolutionary stages during volcano growth are more diverse than previously described. Based on combining available composition, isotopic age, and geologically constrained volume data for each of the component volcanoes, this overview provides the first integrated models for overall growth of any Hawaiian island. In contrast to prior morphologic models for volcano evolution (preshield, shield, postshield), growth increasingly can be tracked by age and volume (magma supply), defining waxing alkalic, sustained tholeiitic, and waning alkalic stages. Data and estimates for individual volcanoes are used to model changing magma supply during successive compositional stages, to place limits on volcano life spans, and to interpret composite assembly of the island. Volcano volumes vary by an order of magnitude; peak magma supply also varies sizably among edifices but is challenging to quantify because of uncertainty about volcano life spans. Three alternative models are compared: (1) near-constant volcano propagation, (2) near-equal volcano durations, (3) high peak-tholeiite magma supply. These models define inconsistencies with prior geodynamic models, indicate that composite growth at Hawaii peaked ca. 800–400 ka, and demonstrate a lower current rate. Recent age determinations for Kilauea and Kohala define a volcano propagation rate of 8.6 cm/yr that yields plausible inception ages for other volcanoes of the Kea trend. In contrast, a similar propagation rate for the less-constrained Loa trend would require inception of Loihi Seamount in the future and ages that become implausibly large for the older volcanoes. An alternative rate of 10.6 cm/yr for Loa-trend volcanoes is reasonably consistent with ages and volcano spacing, but younger Loa volcanoes are offset from the Kea trend in age-distance plots. Variable magma flux at the Island of Hawaii, and longer-term growth of the Hawaiian chain as discrete islands rather than a continuous ridge, may record pulsed magma flow in the hotspot/plume source.} 2013 10 1553-040X 10.1130/GES00935.1 Geosphere 9 1348-1383 5 https://doi.org/10.1130/GES00935.1 Peter W. Lipman Andrew T. Calvert article Pittarello20131160 El'gygytgyn in northeast Chukotka (Russia) is a 3.6 Ma, 18-km-diameter impact structure. The impact crater was recently drilled in the framework of a project sponsored by the International Continental Scientific Drilling Program (ICDP). Target rocks at the El'gygytgyn area are dominated by the felsic members of the Late Cretaceous Okhotsk-Chukotka Volcanic Belt (OCVB). Such a target lithology is unique among terrestrial impact craters, thereby providing the opportunity to study shock metamorphism in siliceous volcanic rocks. Here, we present a petrographic, geochemical, and isotopic study of the section of the drill core underneath the lacustrine sediments, extending from ∼316 m to 517 m below the lake bottom (blb). The drill core stratigraphy includes ∼80 m of suevite and a cross section through a volcanic suite, which consists of (1) a middle section (∼390-423 mblb) with dominant felsic tuffs and a few mafic members, and (2) a welded rhyolitic-dacitic ignimbrite (∼423-517 mblb). The melt fragments embedded in the suevite are interpreted as being impact-related by comparison with impact glasses from the crater and in opposition to the target rock, which does not include similar melts. A suevitic dyke crosscuts the lower section of the core at the depth 471.40 mblb. Evidence for shock metamorphism is concentrated in the upper 10 m of the drill core and almost limited to the suevitic breccia. The geochemical and isotope (Nd and Hf) composition of samples from the target and the drill core reveals relationships to the "Berlozhya magmatic assemblage" (BMA) arguing for similar source magmas. The primitive upper mantle (PUM)-normalized trace element plot of rocks investigated here confirms a subduction-related signature, as previously proposed for rocks from both OCVB and BMA. © The Meteoritical Society, 2013. 2013 English 10869379 10.1111/maps.12088 Meteoritics and Planetary Science 48 1160-1198 Department of Lithospheric Research, University of Vienna, Althanstrasse 14, Vienna, 1090, Austria; Institute of Mineralogy, University of Cologne, Zuelpicher Str. 49b, Cologne, 50674, Germany; Natural History Museum, Burgring 7, Vienna, 1010, Austria; Rheinische Friedrich Wilhelms-Universität Bonn, Steinmann-Institut für Geologie, Mineralogie und Paläontologie, Abt. Endogene Prozesse, Poppelsdorfer Schloss, Bonn, 53115, Germany 7 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84880167788&doi=10.1111%2fmaps.12088&partnerID=40&md5=486a9547827a75c46efa0d47d6fcd3c3 cited By 20 L. Pittarello T. Schulz C. Koeberl J.E. Hoffmann C. Münker article Wittmann20131199 El'gygytgyn is a 18km diameter, 3.6Ma old impact crater in NE Siberia. International Continental Scientific Drilling Program-El'gygytgyn hole 1C was drilled on the frozen crater lake, 2.3km from the crater center to a final depth of 517m below the lake floor. Petrographic and geochemical analyses of 26 drill core samples, three impact melt rocks from the surface, and seven glass spherules from surface deposits outside the crater are used to characterize the impactite inventory at El'gygytgyn. The bottom 98m of hole 1C intersected monomict brecciated, unshocked, rhyolitic ignimbrite with minor intercalations of polymict breccia and mafic inclusions. These lithologies are overlain by 89m of polymict breccia whose components occasionally exhibit scarce, low-degree shock metamorphic features. This unit is succeeded by 10m of suevite that contains about 1 vol% glassy impact melt shards <1cm in size and a low amount of shock metamorphosed lithic clasts. The suevite is capped by a reworked fallout deposit that constitutes a transition over 4m into lacustrine sedimentation. A higher abundance of shock metamorphosed lithic clasts, and glass spherules, some with Ni-rich spinel and admixture of an ultramafic component, characterize this unit. We tentatively interpret this impactite section as allochthonous breccia in the vicinity of El'gygytgyn's central ring uplift. The geochemical compositions of seven glass spherules from terrace deposits 2km outside the crater and eight spherules from the reworked fallout deposit in hole 1C show far greater variability than the composition of impact melt shards and impact melt rocks. Some of these spherules also show strong enrichments in siderophile elements. © The Meteoritical Society, 2013. 2013 10.1111/maps.12019 Meteoritics and Planetary Science 48 1199-1235 Department of Earth and Planetary Sciences, Washington University St. Louis, Campus Box 1169, 1 Brookings Dr., St. Louis, MO 63130-4899, United States; Lunar and Planetary Institute, 3600 Bay Area Boulevard, Houston, TX 77058, United States; Earth System Science, Department of Geology, Vrije Universiteit Brussel, Pleinlaan 2, BE-1050 Brussels, Belgium; Department of Analytical Chemistry, Ghent University, Krijgslaan 281-S12, BE - 9000 Ghent, Belgium; Institut für Planetologie (IfP), Westfälische Wilhelms-Universität Münster (WWU), Wilhelm-Klemm-Str. 10, D-48149 Münster, Germany 7 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84876407831&doi=10.1111%2fmaps.12019&partnerID=40&md5=cfe31d510535e499b160ba4116236e1b cited By 29 A. Wittmann S. Goderis P. Claeys F. Vanhaecke A. Deutsch L. Adolph article Wittmann20131199 El'gygytgyn is a 18km diameter, 3.6Ma old impact crater in NE Siberia. International Continental Scientific Drilling Program-El'gygytgyn hole 1C was drilled on the frozen crater lake, 2.3km from the crater center to a final depth of 517m below the lake floor. Petrographic and geochemical analyses of 26 drill core samples, three impact melt rocks from the surface, and seven glass spherules from surface deposits outside the crater are used to characterize the impactite inventory at El'gygytgyn. The bottom 98m of hole 1C intersected monomict brecciated, unshocked, rhyolitic ignimbrite with minor intercalations of polymict breccia and mafic inclusions. These lithologies are overlain by 89m of polymict breccia whose components occasionally exhibit scarce, low-degree shock metamorphic features. This unit is succeeded by 10m of suevite that contains about 1 vol% glassy impact melt shards <1cm in size and a low amount of shock metamorphosed lithic clasts. The suevite is capped by a reworked fallout deposit that constitutes a transition over 4m into lacustrine sedimentation. A higher abundance of shock metamorphosed lithic clasts, and glass spherules, some with Ni-rich spinel and admixture of an ultramafic component, characterize this unit. We tentatively interpret this impactite section as allochthonous breccia in the vicinity of El'gygytgyn's central ring uplift. The geochemical compositions of seven glass spherules from terrace deposits 2km outside the crater and eight spherules from the reworked fallout deposit in hole 1C show far greater variability than the composition of impact melt shards and impact melt rocks. Some of these spherules also show strong enrichments in siderophile elements. © The Meteoritical Society, 2013. 2013 English 10869379 10.1111/maps.12019 Meteoritics and Planetary Science 48 1199-1235 Department of Earth and Planetary Sciences, Washington University St. Louis, Campus Box 1169, 1 Brookings Dr., St. Louis, MO 63130-4899, United States; Lunar and Planetary Institute, 3600 Bay Area Boulevard, Houston, TX 77058, United States; Earth System Science, Department of Geology, Vrije Universiteit Brussel, Pleinlaan 2, BE-1050 Brussels, Belgium; Department of Analytical Chemistry, Ghent University, Krijgslaan 281-S12, BE - 9000 Ghent, Belgium; Institut für Planetologie (IfP), Westfälische Wilhelms-Universität Münster (WWU), Wilhelm-Klemm-Str. 10, D-48149 Münster, Germany 7 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84876407831&doi=10.1111%2fmaps.12019&partnerID=40&md5=cfe31d510535e499b160ba4116236e1b cited By 29 A. Wittmann S. Goderis P. Claeys F. Vanhaecke A. Deutsch L. Adolph article 2013 10.19839/j.cnki.dcxzz.2013.04.036 Journal of Stratigraphy 37 574-576 4 Y. Zhang article Raschke20131251 The 3.6 Ma old and 18 km diameter El'gygytgyn impact structure in NE Siberia was drilled in 2008/09 by ICDP (International Continental Scientific Drilling Program). A 517 m long core hole (D1c) was drilled into the outer flank of the central uplift structure, with an overall core recovery of approximately 63%. Thereby, approximately 315 m lake sediments and approximately 202 m impactites were recovered. Here, we present a detailed petrographic and geochemical assessment of the impact breccia and bedrock sections in this core. The 97 m long lower bedrock unit (517-420 m below lake floor [blf]) consists of an ignimbrite. In the overlying upper bedrock unit (420-390 mblf), the core recovered a sequence of similar ignimbrite and several decimeters of mafic rocks. We interpret these units as rocks that are located close to their former, preimpact position, but have been somewhat rotated due to collapse of the central uplift (i.e., it represents parautochthonous basement). From about 390 to 328 mblf occurs a suevite package with an impact melt poor, clast-dominated matrix, and lithic and mineral clasts that cover the entire range of volcanic target rocks known from the El'gygytgyn region. All stages of shock metamorphism (unshocked to melted) were observed in clasts, and in microclasts of the matrix, of suevite from different depths. Immediately below this package, at the contact to the underlying bedrock, occurs a 1 m wide sheared zone within vitrophyric ignimbrite, which we consider the actual crater floor. The uppermost approximately 12 m, from 328-316 mblf depth, seem to comprise reworked suevite, consisting of a mixture of sediments and suevite with more and, on average, stronger shocked minerals than found in the main suevite unit. This includes a small component of glassy spherules and impact melt fragments. Toward the top of this unit, lake sediments progressively become the dominant material in this section. We assume that this unit contains a fallback component from the ejecta plume that was mixed with the first sediments of the postimpact crater lake, and possibly some rocks that slumped off the inner crater wall-similar to a thin layer at the base of the sediment section of borehole LB-5A recovered in Lake Bosumtwi (Ghana). © The Meteoritical Society, 2013. 2013 English 10869379 10.1111/maps.12087 Meteoritics and Planetary Science 48 1251-1286 Museum für Naturkunde, Leibniz-Institut für Evolutions- und Biodiversitätsforschung, Invalidenstraße 43, Berlin, 10115, Germany; Humboldt-Universität zu Berlin, Unter den Linden 6, Berlin, 10099, Germany 7 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84876417937&doi=10.1111%2fmaps.12087&partnerID=40&md5=237bf44410e2e8c75eb43732d648b79a cited By 32 U. Raschke R.T. Schmitt W.U. Reimold article cp-9-119-2013 This study focuses on the temperature field observed in boreholes drilled as part of interdisciplinary scientific campaign targeting the El'gygytgyn Crater Lake in NE Russia. Temperature data are available from two sites: the lake borehole 5011-1 located near the center of the lake reaching 400 m depth, and the land borehole 5011-3 at the rim of the lake, with a depth of 140 m. Constraints on permafrost depth and past climate changes are derived from numerical simulation of the thermal regime associated with the lake-related talik structure. The thermal properties of the subsurface needed for these simulations are based on laboratory measurements of representative cores from the quaternary sediments and the underlying impact-affected rock, complemented by further information from geophysical logs and data from published literature. <br><br> The temperature observations in the lake borehole 5011-1 are dominated by thermal perturbations related to the drilling process, and thus only give reliable values for the lowermost value in the borehole. Undisturbed temperature data recorded over more than two years are available in the 140 m deep land-based borehole 5011-3. The analysis of these observations allows determination of not only the recent mean annual ground surface temperature, but also the ground surface temperature history, though with large uncertainties. Although the depth of this borehole is by far too insufficient for a complete reconstruction of past temperatures back to the Last Glacial Maximum, it still affects the thermal regime, and thus permafrost depth. This effect is constrained by numerical modeling: assuming that the lake borehole observations are hardly influenced by the past changes in surface air temperature, an estimate of steady-state conditions is possible, leading to a meaningful value of 14 ± 5 K for the post-glacial warming. The strong curvature of the temperature data in shallower depths around 60 m can be explained by a comparatively large amplitude of the Little Ice Age (up to 4 K), with low temperatures prevailing far into the 20th century. Other mechanisms, like varying porosity, may also have an influence on the temperature profile, however, our modeling studies imply a major contribution from recent climate changes. © Author(s) 2013. 2013 English 18149324 10.5194/cp-9-119-2013 Climate of the Past 9 119-133 Geophysica Beratungsgesellschaft MbH, Aachen, Germany; Alfred Wegener Institute for Polar and Marine Research, Potsdam, Germany; Department of Earth Sciences, Astronomy and Astrophysics, Faculty of Physical Sciences, Universidad Complutense de Madrid, Madrid, Spain 1 borehole; climate variation; crater lake; drilling; interdisciplinary approach; Last Glacial Maximum; Little Ice Age; paleoclimate; paleotemperature; permafrost; reconstruction; recovery plan; surface temperature; talik, Chukchi; Elgygytgyn Lake; Russian Federation https://cp.copernicus.org/articles/9/119/2013/ cited By 12 D. Mottaghy G. Schwamborn V. Rath article Katz20131488 Integrated Ocean Drilling Program (IODP) Expedition 313 drilled three holes (Sites M27, M28, and M29; 34-36 m present water depth) across a series of prograding clinothems from the inner continental shelf of the New Jersey (USA) margin, a region that is sensitive to sea-level change. We examined 702 late Eocene to Miocene samples for benthic foraminiferal assemblages and planktonic foraminiferal abundances. We integrate our results with lithofacies to reconstruct paleobathymetry. Biofacies at all three sites indicate a long-term shallowing-upward trend as clinothems built seaward and sediment fi lled accommodation space. Patterns in biofacies and lithofacies indicate shallowing-and deepening-upward successions within individual sequences, providing the basis to recognize systems tracts, and therefore sequence stratigraphic relationships in early to early-middle Miocene sequences (ca. 23-13 Ma). The clinothem bottomsets and the lower portions of the foresets, which contain the thickest parts of clinothems, yield the deepest water biofacies. Shallower bio facies characterize the sequences in the upper portions of the clinothem foresets and on the topsets. Topsets are characterized by transgressive (TST) and highstand systems tracts (HST). Foresets contain lowstand systems tracts (LST), TSTs, and HSTs. Flooding surfaces mark parasequence boundaries within LSTs, TSTs, and HSTs. Superimposed on the long-term trends, short-term variations in paleowater depth are likely linked to global sea-level changes indicated by global oxygen isotopic variations. 2013 English 1553040X 10.1130/GES00872.1 Geosphere 9 1488-1513 Department of Earth and Environmental Sciences, Rensselaer Polytechnic Institute, 110 8th Street, Troy New York 12180, United States; Department of Earth and Planetary Sciences, Rutgers University, Piscataway, New Jersey 08854, United States; New Jersey Geological Survey, PO Box 427, Trenton New Jersey 07640, United States; Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139-4307, United States 6 Accommodation space; Benthic foraminifera; Foraminiferal assemblages; Highstand systems tract; Individual sequences; Integrated ocean drilling programs; Sequence-stratigraphic interpretation; Short-term variations, Sea level; Stratigraphy; Tectonics, Coastal zones, benthic foraminifera; continental shelf; depositional sequence; Eocene; Miocene; Ocean Drilling Program; parasequence; sequence boundary; sequence stratigraphy; systems tract; transgression, Atlantic Ocean; New Jersey Shelf, Foraminifera https://www.scopus.com/inward/record.uri?eid=2-s2.0-84889675272&doi=10.1130%2fGES00872.1&partnerID=40&md5=bef354d5234c70286656595ece33203f cited By 23 M.E. Katz J.V. Browning K.G. Miller D.H. Monteverde G.S. Mountain R.H. Williams article Huang201395 A dramatic change in atmospheric composition has been postulated because of global carbon cycle disruption during the Cretaceous (K)-Tertiary (T) transition following the Chicxulub impact and Deccan Trap eruptions. Here, pedogenic carbonates were collected from drill core of a borehole (SK-1 (N)) straddling the Late Cretaceous and early Paleocene strata in the Songliao Basin, northeast China, to reconstruct atmospheric CO2 concentrations using a paleosol paleobarometer. Our estimates for atmospheric pCO2 from paleosol carbonates range between 277±115ppmv and 837±164ppmv between 67.8Ma and 63.1Ma. One large (~66-65.5Ma) and several small CO2 spikes (~64.7-~64.2Ma) during the latest Maastrichtian to earliest Danian are reported here and incorporated with previously published pCO2 estimates also estimated from paleosol carbonates. These CO2 spikes are attributed to one-million-year-long emplacement of the large Deccan flood basalts along with the extraterrestrial impact at the K-T boundary. © 2013 Elsevier B.V. 2013 English 00310182 10.1016/j.palaeo.2013.01.005 Palaeogeography, Palaeoclimatology, Palaeoecology 385 95-105 Department of Environmental Science and Engineering, Sichuan University, Chengdu, Sichuan 610065, China; Department of Geological Sciences, University of Oregon, Eugene, OR 97403, United States; School of Earth Science and Resources, China University of Geosciences, Beijing 100083, China; Exploration and Development Research Institute, Daqing Oilfield Company Ltd., Daqing, Helongjiang 163712, China atmospheric chemistry; borehole; carbon cycle; carbon dioxide; carbonate; crater; Cretaceous-Tertiary boundary; Danian; flood basalt; Maastrichtian; paleoatmosphere; paleoclimate; paleosol; pedogenesis; volcanic eruption, Atlantic Ocean; Bay of Campeche; Chicxulub Crater; China; Deccan; Gulf of Mexico; India; Mexico [North America]; Songliao Basin; Yucatan https://www.scopus.com/inward/record.uri?eid=2-s2.0-84879889356&doi=10.1016%2fj.palaeo.2013.01.005&partnerID=40&md5=bb244f1d3cdefaa6ca3ef888e7c5382b cited By 47 C. Huang G.J. Retallack C. Wang Q. Huang article Losiak2013297 The Bosumtwi crater is 10.5. km in diameter, 1.07. Ma old, well preserved impact structure located in Ghana (centered at 06°30'N, 01°25'W). It was excavated in rocks of the Early Proterozoic Birimian Supergroup, part of the West African craton. Here, we present a full and detailed characterization of the three granitoid complexes and one mafic dike in the vicinity of the Bosumtwi crater in terms of petrology, major and trace element geochemistry, geochronology, and isotopic composition. This allows us to characterize magmatic evolution of the West African Craton in this area and better understand the geological framework and target rocks of the impact.This study shows that the similar composition (strongly peraluminous muscovite granites and granodiorites) and age (between 2092. ±. 6. Ma and 2098. ±. 6. Ma) of all granitic intrusions in the proximity of the Bosumtwi crater suggest that they are co-genetic. Granitoids were probably formed as a result of anatexis of TTGs (or rocks derived from them) at relatively low pressure and temperature. We propose that the intrusions from the Bosumtwi area are genetically related to the Banso granite occurring to the east of the crater and can be classified as basin-type, late-stage granitoids. Also a mafic dike located to the NE of the Bosumtwi crater seems to be genetically related to those felsic intrusions. Based on those findings a revised version of the geological map of the Bosumtwi crater area is proposed. © 2013. Article 2013 English 00244937 10.1016/j.lithos.2013.06.002 Lithos 177 297 – 313 Ghana; geochronology; granite; granitoid; igneous geochemistry; igneous intrusion; impact structure; isotopic composition; magmatism; petrogenesis; petrology; Proterozoic; trace element https://www.scopus.com/inward/record.uri?eid=2-s2.0-84881500197&doi=10.1016%2fj.lithos.2013.06.002&partnerID=40&md5=147cdd6f1132cab881d301c7664c4b01 Cited by: 11 Anna Losiak Toni Schulz Robert Buchwaldt Christian Koeberl article Schäbitz2013175 Based on modern pollen samples from different vegetation units in southern Patagonia, showing a close relation to yearly amounts of precipitation and mean annual temperatures, different pollen-climate transfer functions are developed and tested. Comparing the performance of MAT (Modern Analogue Techniques), WA (Weighted Average), as well as WAPLS (Weighted Average Partial Least Square) statistical techniques, it is possible to determine the statistically most robust model (WAPLS for precipitation). This transfer function is then used to estimate palaeoprecipitation amounts based on Laguna Potrok Aike pollen results for the last 16,000 years. Generally, the results of the precipitation model indicate less precipitation during the Lateglacial and alternating wet and dry periods during the Holocene. The Holocene started with higher amounts of precipitation until about 8kacal.BP, followed by a period with lower amounts between 8 and 2.5kacal.BP, while the Late Holocene shows a general increase in precipitation. Comparisons with former shoreline reconstructions and carbonate concentrations in the sediments of Laguna Potrok Aike not always show similarities due to the complex environmental factors recorded by these proxies. Moreover, changes in the moisture availability due to the interplay of precipitation and temperature, cannot be reconstructed directly. Nevertheless, the general long-term trend of palaeoprecipitation is in accordance with the absolute moisture content in the air, which is determined mainly by temperature: during cold periods with less absolute moisture, the model shows less precipitation. Moreover, the model also points to a relation with the position and strength of the Southern Hemisphere Westerlies. © 2013 Elsevier Ltd. Article 2013 10.1016/j.quascirev.2012.12.006 Quaternary Science Reviews 71 175 – 190 Argentina; Laguna Potrok Aike; Patagonia; Santa Cruz [Argentina]; Moisture; Statistical methods; Transfer functions; ICDP-project PASADO; Late quaternary; Modern pollen samples; Palaeoclimate; Pollen; Precipitation reconstruction; Southern Hemisphere; carbonate; concentration (composition); environmental factor; Holocene; numerical model; pollen; precipitation (climatology); reconstruction; Southern Hemisphere; temperature effect; Lasers https://www.scopus.com/inward/record.uri?eid=2-s2.0-84878921228&doi=10.1016%2fj.quascirev.2012.12.006&partnerID=40&md5=07458a9862ea79d982cdc0398e922c9b Cited by: 42 Frank Schäbitz Michael Wille Jean-Pierre Francois Torsten Haberzettl Flavia Quintana Christoph Mayr Andreas Lücke Christian Ohlendorf Virginia Mancini Marta M. Paez Aldo R. Prieto Bernd Zolitschka article cp-9-1933-2013 Seismic profiles of Far East Russian Lake El'gygytgyn, formed by a meteorite impact some 3.6 million years ago, show a stratified sediment succession that can be separated into subunits Ia and Ib at approximately 167 m below lake floor (Combining double low line∼3.17 Ma). The upper (Ia) is well-stratified, while the lower is acoustically more massive and discontinuous. The sediments are intercalated with frequent mass movement deposits mainly in the proximal areas, while the distal region is almost free of such deposits at least in the upper part. In spring 2009, a long core drilled in the lake center within the framework of the International Continental Scientific Drilling Program (ICDP) penetrated the entire lacustrine sediment succession down to ∼320 m below lake floor and about 200 m farther into the meteorite-impact-related bedrock. Downhole logging data down to 390 m below lake floor show that the bedrock and the lacustrine part differ significantly in their petrophysical characteristics. The contact between the bedrock and the lacustrine sediments is not abrupt, but rather transitional with a variable mixture of impact-altered bedrock clasts in a lacustrine matrix. Physical and chemical proxies measured on the cores can be used to divide the lacustrine part into five different statistical clusters. These can be plotted in a redox-condition vs. input-type diagram, with total organic carbon content and magnetic susceptibility values indicating anoxic or oxic conditions and with the Si/Ti ratio representing more clastic or more biogenic input. Plotting the clusters in this diagram allows identifying clusters that represent glacial phases (cluster I), super interglacials (cluster II), and interglacial phases (clusters III and IV). © Author(s) 2013. 2013 English 18149324 10.5194/cp-9-1933-2013 Climate of the Past 9 1933-1947 Alfred Wegener Institute Helmholtz, Centre for Polar and Marine Research, Columbusstraße, 27515 Bremerhaven, Germany; University of Cologne, Institute of Geology and Mineralogy, Zülpicher Straße 49A, 50674 Cologne, Germany; German Research Centre for Geosciences, Telegrafenberg, 14473 Potsdam, Germany 4 bedrock; biogenic deposit; clastic sediment; diagram; drilling; interglacial; lacustrine deposit; mass movement; meteorite; petrology; physicochemical property; redox conditions, Chukchi; Elgygytgyn Lake; Russian Federation https://cp.copernicus.org/articles/9/1933/2013/ cited By 12 A. C. Gebhardt A. Francke J. Kück M. Sauerbrey F. Niessen V. Wennrich M. Melles article Miller201374 We used cores and logs from Integrated Ocean Drilling Program (IODP) Expedition 313 to generate biostratigraphic, lithofacies, biofacies, and geochemical data that constrain the ages and paleoenvironments of Pleistocene sequences. We integrate sequence stratigraphy on cores with new seismic stratigraphic data to interpret the Pleistocene history of the Hudson shelf valley and paleoenvironmental and sea-level changes on the inner to middle continental shelf. Improved age control compared to previous studies is provided by integrated calcareous nannofossil biostratigraphy, Sr isotopic stratigraphy, and amino acid racemization. We recognize four upper Pleistocene-Holocene sequences: sequence uP1 is correlated with Marine Isotope Chrons (MIC; "chron" is the correct stratigraphic term for a time unit, not "stage") 7 or 5e, sequence uP2 with MIC 5c, sequence uP3 with MIC 5a, and sequence uP4 with the latest Pleistocene to Holocene (MIC 1-2). However, within our age resolution it is possible that sequences uP2 and uP3 correlate with MIC 4-3c and 3a, respectively, as suggested by previous studies. Lower Pleistocene sequences lP1 and lP2 likely correlate with peak interglacials (e.g., MIC 31 and MIC 45 or 47, respectively). Thus, we suggest that preservation of sequences occurs only during peak eustatic events (e.g., MIC 45 or 47, MIC 31, and MIC 5), unless they are preserved in eroded valleys. The architecture of the Pleistocene deposits at Sites M27 and M29 is one of thin remnants of highstand and transgressive systems tracts, with lowstand deposits only preserved in the thalwegs of incised valleys. Incised valleys at the bases of sequences uP3 (IODP Site M27) and uP2 (IODP Site M29) document more southward courses of the paleo-Hudson valley, compared to the more southeastward course of the MIC 1-2 paleo-Hudson valley. The patchy distribution of Pleistocene sequences beneath the New Jersey inner-middle continental shelf is due to low accommodation during an interval of large eustatic changes; this predicts that sequences in such settings will be discontinuous, patchy, and difficult to correlate, consistent with previous studies in Virginia and North Carolina. © 2013 Geological Society of America. 2013 English 1553040X 10.1130/GES00795.1 Geosphere 9 74-95 Department of Earth and Planetary Sciences, Rutgers University, Piscataway, NJ 08854, United States; GNS Science, Department of Paleontology, PO Box 30368, Lower Hutt 5040, New Zealand; Department of Geology, University of Delaware, Penny Hall, Newark, DE 19716, United States 1 biofacies; biostratigraphy; continental shelf; eustacy; incised valley; integrated approach; lithofacies; marine isotope stage; nanofossil; Ocean Drilling Program; paleoceanography; paleoenvironment; Pleistocene; Pleistocene-Holocene boundary; sea level change; seismic stratigraphy; sequence stratigraphy; thalweg; transgression, New Jersey; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-84873511052&doi=10.1130%2fGES00795.1&partnerID=40&md5=b9f8e75d882e8026d3ae77b9f82ca41c cited By 19 K.G. Miller P.J. Sugarman J.V. Browning R.E. Sheridan D.K. Kulhanek D.H. Monteverde J.F. Wehmiller C. Lombardi M.D. Feigenson article Brigham-Grette20131421 Understanding the evolution of Arctic polar climate from the protracted warmth of the middle Pliocene into the earliest glacial cycles in the Northern Hemisphere has been hindered by the lack of continuous, highly resolved Arctic time series. Evidence from Lake El'gygytgyn, in northeast (NE) Arctic Russia, shows that 3.6 to 3.4 million years ago, summer temperatures were ∼8°C warmer than today, when the partial pressure of CO2 was ∼400 parts per million. Multiproxy evidence suggests extreme warmth and polar amplification during the middle Pliocene, sudden stepped cooling events during the Pliocene-Pleistocene transition, and warmer than present Arctic summers until ∼2.2 million years ago, after the onset of Northern Hemispheric glaciation. Our data are consistent with sea-level records and other proxies indicating that Arctic cooling was insufficient to support large-scale ice sheets until the early Pleistocene. 2013 English 00368075 10.1126/science.1233137 Science 340 American Association for the Advancement of Science 1421-1427 Department of Geosciences, University of Massachusetts, 611 North Pleasant Street, Amherst, MA 01003, United States; Institute of Geology and Mineralogy, University of Cologne, Zuelpicher Strasse 49a, D-50674 Cologne, Germany; North-East Interdisciplinary Scientific Research Institute, Far East Branch of the Russian Academy of Sciences, Portovaya Street 16, 685000 Magadan, Russian Federation; Free University Berlin, Institute of Geological Sciences, Haus D, Malteser Strasse 74-100, D-12249 Berlin, Germany; Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences, Telegrafenberg, D-14473 Potsdam, Germany; Department of Ecology and Environmental Science, Umeå University, SE-901 87 Umeå, Sweden; Department of Physical and Earth Sciences, Worcester State University, Worcester, MA 01602, United States; Alfred Wegener Institute for Polar and Marine Research, Am Handelshafen 12, D-27570 Bremerhaven, Germany; Department of Geology, Bowling Green State University, OH 43403, United States; Alfred Wegener Institute for Polar and Marine Research, Research Unit Potsdam, Telegrafenberg A43, D-14473 Potsdam, Germany; Department of Geology, Lund University, Sölvegatan 12, S-223 62 Lund, Sweden 6139 carbon dioxide, climate variation; cooling; ice sheet; Northern Hemisphere; paleoclimate; Pliocene-Pleistocene boundary; proxy climate record; sea level change, arctic climate; article; carbon dioxide tension; cooling; glacial period; glaciation; greenhouse gas; ice sheet; Pleistocene; Pliocene; priority journal; summer, Arctic Ocean; Russian Federation https://www.scopus.com/inward/record.uri?eid=2-s2.0-84879256879&doi=10.1126%2fscience.1233137&partnerID=40&md5=bd2e5d4102b83c49bdb72d7560e1e3d0 cited By 181 J. Brigham-Grette M. Melles P. Minyuk A. Andreev P. Tarasov R. DeConto S. Koenig N. Nowaczyk V. Wennrich P. Rosen E. Haltia T. Cook C. Gebhardt C. Meyer-Jacob J. SNYDER U. Herzschuh article cp-9-719-2013 2013 10.5194/cp-9-719-2013 Climate of the Past 9 719-733 2 https://cp.copernicus.org/articles/9/719/2013/ A. Zander A. Hilgers article cp-9-1455-2013 Modern process studies of the hydrologic balance of Lake El'gygytgyn, central Chukotka, and the sediment income from the catchment were carried out during a field campaign in spring and summer 2003. Despite high uncertainties due to the limited data, the results provide important first estimates for better understanding the modern and past sedimentation processes in this basin. Formed ca. 3.6 million years ago as a result of a meteorite impact, the basin contains one of the longest paleoclimate records in the terrestrial Arctic. Fluvial activity is concentrated over the short snowmelt period (about 20 days in second part of June). Underground outflow plays a very important role in the water balance and predominates over surface outflow. The residence time of the lake water is estimated to be about 100 yr. © 2013. CC Attribution 3.0 License. 2013 English 18149324 10.5194/cp-9-1455-2013 Climate of the Past 9 1455-1465 Arctic and Antarctic Research Institute, Bering Street 38, 199397 St.-Petersburg, Russian Federation; St. Petersburg State University, Faculty of Geography and Geoecology, 10 line V.O., 33, 199178, St.-Petersburg, Russian Federation; Water and Environmental Research Center, Institute of Northern Engineering, 306 Tanana Drive, Duckering Room 437, United States; University of Alaska Fairbanks, Fairbanks, AK 99775-5860, United States; Department of Geosciences, University of Massachusetts, P.O. Box 35820, Amherst, MA 01003-5820, United States; Alfred Wegener Institute for Polar and Marine Research, Telegrafenberg, 14471 Potsdam, Germany; Institute of Applied Geology, Technical University of Berlin, Ackerstrasse 76, 13355 Berlin, Germany 4 catchment; data acquisition; estimation method; fluvial deposit; outflow; paleoclimate; residence time; seasonal variation; terrestrial ecosystem; uncertainty analysis; water budget, Chukchi; Elgygytgyn Lake; Russian Federation https://cp.copernicus.org/articles/9/1455/2013/ cited By 16 G. Fedorov M. Nolan J. Brigham-Grette D. Bolshiyanov G. Schwamborn O. Juschus article Wang2013125 The study of sedimentary pyrite morphological characteristics provides useful information on depositional environments and early diagenic processes and can be used as an indicator of redox conditions in ancient lake bottom waters. The results of this study in the Songliao basin in northeastern China show that euhedral crystals and framboids are the dominant pyrite forms in the mudstones of the first member of the Qingshankou Formation (K2qn1). The framboidal size distribution indicates that during the deposition of K2qn1, redox conditions in the bottom water fluctuated from oxic-dysoxic to euxinic-anoxic to oxic-dysoxic. The presence of euxinic-anoxic bottom water suggests that an anoxic event developed in the Songliao ancient-lake and continued for 196ka. The development of an anoxic bottom environment was the most important factor in hydrocarbon source rock formation in the Songliao Basin. © 2012 Elsevier B.V. 2013 English 00310182 10.1016/j.palaeo.2012.09.027 Palaeogeography, Palaeoclimatology, Palaeoecology 385 125-136 Institute of Mineral Resources, Chinese Academy of Geological Sciences, Beijing 100037, China; China University of Geosciences, Beijing 100083, China; Exploration and Development Research Institute of the Daqing Oil Field Corporation Ltd., Daqing 163712, China anoxic conditions; bottom water; Cretaceous; depositional environment; diagenesis; hydrocarbon resource; lake water; mudstone; pyrite; redox conditions; size distribution; source rock, China; Songliao Basin https://www.scopus.com/inward/record.uri?eid=2-s2.0-84879874865&doi=10.1016%2fj.palaeo.2012.09.027&partnerID=40&md5=b53546f93855ed58208c9250de9fb25f cited By 54 P. Wang Y. Huang C. Wang Z. Feng Q. Huang article cp-9-1253-2013 2013 10.5194/cp-9-1253-2013 Climate of the Past 9 1253-1269 3 https://cp.copernicus.org/articles/9/1253/2013/ M. Nolan article Goderis2013417 The discovery over 30years ago at Gubbio (Italy) and Caravaca (Spain) of an enrichment in the concentrations of iridium (Ir) and the other platinum group elements (PGE) by up to four orders of magnitude (Irmax=0.10-87ng/g) compared to average continental crustal background levels remains one of the most important discoveries in the Earth sciences. Since then, similar anomalies have been detected in more than 120 Cretaceous-Paleogene (K-Pg) boundary sites worldwide. Highly elevated Ir and other siderophile element abundances in roughly chondritic ratios are considered strong indicators for the presence of a meteoritic contribution in impact-related lithologies (melt rocks, impact ejecta material, etc.), delivered when an extraterrestrial object strikes Earth. The presented work adds 113 unpublished PGE analyses of 38 K-Pg sections worldwide to the existing literature. The analytical protocol relied on for this purpose consisted of a combination of a nickel-sulfide fire assay pre-concentration technique and subsequent trace metal determination via inductively coupled plasma-mass spectrometry (ICP-MS). Through repeated determination of key siderophile elements (i.e., Cr, Co, Ni, and PGE), the importance of sampling, nugget effects, and analytical methodologies applied becomes more apparent. Even more critically, these analytical effects are superimposed by the local syn- and post-depositional conditions that have affected the pristine meteoritic signature of the K-Pg impactor, including potential fractionation during vaporization and condensation, dissimilar PGE carrier phases, terrestrial PGE input, sedimentation rate, reworking, diagenesis, bioturbation, and chemical diffusion. While chondrite-normalized PGE patterns of individual sites appear relatively flat (i.e., chondritic), strong variations in siderophile element content and inter-element ratios exist between K-Pg locations, inter-laboratory measurements, and replicate analyses, hampering a precise projectile identification using (highly) siderophile elements. Only when considering improved databases of siderophile element concentrations in meteorites, in combination with linear regression analysis to calculate inter-element ratios from a large suite of ejecta deposit sites, the nature of the K-Pg projectile can be resolved. Application of this methodology to an extensive data set of continental and marine sites, very proximal to distal to the Chicxulub impact structure, supports a carbonaceous chondritic impactor (type CM or CO). © 2013 Elsevier Ltd. 2013 10.1016/j.gca.2013.06.010 Geochimica et Cosmochimica Acta 120 417-446 Earth System Science, Vrije Universiteit Brussel, Pleinlaan 2, BE-1050 Brussels, Belgium; Department of Analytical Chemistry, Universiteit Gent, Krijgslaan 281-S12, BE-9000 Ghent, Belgium; Bruker Nano GmbH, Schwarzschildstrasse 12, 12489 Berlin, Germany; Department of Sedimentology, Vrije Universiteit Amsterdam, de Boelelaan 1085, 1081HV Amsterdam, Netherlands; Osservatorio Geologico di Coldigioco, Cda. Coldigioco 4, 62021 Apiro (MC), Italy; Helmholtz-Zentrum Potsdam Deutsches GeoForschungsZentrum GFZ, Telegrafenberg, D-14473 Potsdam, Germany https://www.scopus.com/inward/record.uri?eid=2-s2.0-84882729988&doi=10.1016%2fj.gca.2013.06.010&partnerID=40&md5=3014b4cd6b3f9a757ecb49ad01a13d3a cited By 61 S. Goderis R. Tagle J. Belza J. Smit A. Montanari F. Vanhaecke J. Erzinger P. Claeys article Perugini20138 The ability of chemical elements to diffuse in silicate melts is central to igneous processes. It controls the rates of phase transitions such as crystal growth and dissolution kinetics, the rate of homogenization of compositional gradients generated by fractional crystallization and assimilation of country rocks as well as one of the most intriguing processes of all, magma mixing.A very useful measure, commonly used to quantify the rate of homogenization of chemical elements in silicate melts, is the diffusion coefficient. It is widely approximated to be of a constant value (at a fixed pressure and temperature) for a melt with a given composition and rheology. When dealing with magma mixing processes, melts with different initial compositions and rheological properties (e.g. basalt and rhyolite) coexist in the same system. Under such circumstances, the compositional and rheological dependence of diffusion coefficients must be considered, leading to a considerable increase of complexity in the modeling of magma mixing. Yet, an additional and even more dramatic increase in complexity is due to the fact that the mixing of magmas is undoubtedly a very dynamic process. Scale-invariant distributions of filaments of different melts are generated by stretching and folding dynamics. This has a dual effect on the mobility of chemical elements. On the one hand their mobility increases because of an exponential increase of contact area. On the other hand, mobility can be buffered by the different diffusivities in the melts (larger in the low-viscosity than in the high-viscosity melt). Uphill diffusion of chemical elements is likely to develop at the interface between interacting magmas, further increasing the complexity of the process.Here we aim to understand chemical element mobility during melt homogenization in a magma mixing event under dynamic conditions. We have performed experiments by mixing phonolitic and alkali-basaltic melts. The mixing process was induced using a high-temperature centrifuge apparatus. The rotating speed and acceleration during all experiments were 1850. rpm and 1000. g, respectively. Experiments were performed for 5, 20 and 120. min. Samples were arranged in a buoyantly unstable geometry, with the denser material placed at the inner side of the rotating circle, resulting in injection of the mafic melt into the felsic melt during rotation. The temperature during experimental runs was 1200 (± 1)°C.From the resultant glasses, vortex-like structures generated by repeated stretching and folding dynamics were observed at the interface between the two melts. The concentrations of major and trace elements were then measured along interfaces by electron microprobe and LA-ICP-MS. The mobility of each element was next quantified by calculating the decrease (or relaxation) of concentration variance with time. The first notable result is that for major and trace elements, concentrations variance decays exponentially. The exponent of the exponential function is then chosen as a measure of element mobility. Our results show clearly that different chemical elements homogenize in the melt at differing rates. Amongst the major elements Na is the fastest element followed by Al, Mg, Ca, K and Si. The trace elements, Ba, Rb, Sr, Nb and Zr exhibit similar mobilities. The REE display the lowest mobility and they show a systematic decrease from light to heavy.The results from this study indicate that the decay of concentration variance is a robust tool for obtaining new insights into chemical exchanges during the mixing of silicate melts. Concentration variance includes in a single measure an expression of the influence of all possible factors (e.g. viscosity, composition, fluid-dynamic regime) controlling the mobility of chemical elements during the mixing of two liquids. A new parameter, the Relaxation of Concentration Variance (RCV), is proposed as an effective tool for quantifying the homogenization of chemical elements during the mixing of silicate melts. © 2012 Elsevier B.V. 2013 English 00092541 10.1016/j.chemgeo.2012.10.050 Chemical Geology 335 8-23 Department of Earth Sciences, University of Perugia, Italy; Department of Earth and Environmental Sciences, Ludwig-Maximilian-University, Germany Centrifuge experiments; Chemical exchange; Compositional gradients; Contact areas; Crystal growth and dissolution; Dual effect; Dynamic condition; Dynamic process; Effective tool; Electron microprobes; Element mobility; Exponential increase; Folding dynamics; Fractional crystallization; High temperature; High viscosities; Initial composition; La-ICP-MS; Magma mixing; Major and trace elements; Major elements; Mixing process; Natural melts; New parameters; Pressure and temperature; Rheological property; Rotating speed; Scale-invariant; Silicate melts; Up-hill diffusion, Barium; Centrifuges; Chemical elements; Crystal growth; Diffusion; Dynamics; Experiments; Mixing; Niobium; Rheology; Rubidium; Silicates; Sodium; Spectrometry; Viscosity; Zirconium, Process control, alkali basalt; centrifugal model test; concentration (composition); country rock; dissolution; element mobility; experimental study; fractional crystallization; igneous geochemistry; magma; P-T conditions; reaction kinetics; rheology; silicate melt; trace element https://www.scopus.com/inward/record.uri?eid=2-s2.0-84869871626&doi=10.1016%2fj.chemgeo.2012.10.050&partnerID=40&md5=5148ad116957e853ec311a2b572f31f7 cited By 28 D. Perugini C.P. De Campos D.B. Dingwell A. Dorfman article Mang20135195 We observed two different Verwey transition temperatures in fragments of crystalline basement rocks and impact sediments from the Chesapeake Bay impact structure, USA. Our study aims to the question if this feature can be used as shock indicator in impact craters. We distinguished three generations of magnetite. (1) Primary magnetite in crystalline basement rocks has average grain sizes up to several hundreds of micrometers and shows a regular TV at ≈ 121 K. (2) Shocked magnetite occurs in fragments of crystalline basement rocks and also in the suevite and impact breccia. These magnetites show two Verwey transitions - a regular one and a "lowerature transition" (LTV) at around 89 K. LTV is related to a small grain size fraction, whereas a larger grain size fraction (some hundreds of micrometers) causes the regular TV. The small grain size fraction contains a distinctly higher amount of superficially oxidized material due to the high surface/volume ratio, which causes a decrease of the Verwey transition temperature (LTV). (3) A secondary magnetite generation shows also two Verwey transition temperatures, one at 121 K and a LTV range between 91 and 105 K. The LTV in this generation is also linked to thin oxidized surface layers. This study shows that especially the Verwey transition temperature of small magnetite grains reacts very sensitively to surface oxidation and can therefore not be used as a reliable pressure indicator for impact structures on Earth. Key Points Reduction of Verwey transition due to nonstoichiometry Degree of nonstoichiometry triggered by grain size Surface/volume ratio crucial for reduction of Verwey transition ©2013. American Geophysical Union. All Rights Reserved. 2013 English 21699313 10.1002/jgrb.50291 Journal of Geophysical Research: Solid Earth 118 Blackwell Publishing Ltd 5195-5207 Institut für Angewandte Geowissenschaften, Karlsruher Institut für Technologie, Adenauerring 20, Geb. 50.41, Karlsruhe, D-76131, Germany 10 basement rock; breccia; crystalline rock; grain size; hysteresis; impact structure; low temperature; magnetite; oxidation; suevite; temperature gradient, Chesapeake Bay; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-84889009695&doi=10.1002%2fjgrb.50291&partnerID=40&md5=fb1a878d995dd75640733f1a885e6aaa cited By 9 C. Mang A. Kontny article pini2013report 2013 Alpine and Mediterranean Quaternary 26 vii--ix 1 Roberta Pini article Grosch2013142 This study presents the first multiple sulfur isotope dataset on sulfides from the ca. 3.5-3.2 Ga Onverwacht Group in the Paleoarchean Barberton Greenstone Belt (BGB) of South Africa. In situ δ34SCDT and δ33S values of pyrite (n = 568) are reported from a wide range of hydrothermal, volcanic and sedimentary environments and are used to explore Mid-Archean biogeochemical sulfur cycling. Samples are from fresh drill core collected by the Barberton Scientific Drilling Project that intercepted cherts, metabasalts and sheared ultramafics of the ~3.3-3.35 Ga Kromberg Formation; the sedimentary units of the ~3.432 Ga Noisy formation; and the unconformably underlying metabasaltic pillow lavas of the ~3.472 Ga Hooggenoeg Formation.Pyrite in quartz-carbonate-veins in the lower diamictite of the Noisy sequence records the largest range and most negative δ34SCDT values so far reported from an Archean terrain (δ34SCDT = - 55.04 to +27.46‰). The Noisy sediments also contain detrital and diagenetic pyrites with a significant variation in δ33S of between -0.62 to +1.4‰ and δ34SCDT of between -7.00 and +12.6‰, interpreted to reflect tectonic exposure of these early sediments to atmospheric - shallow marine conditions. Early marine pyrites from the Kromberg Cherts also display strong positive δ33S values up to +2.50‰ with narrow range in δ34SCDT values (-6.00 to +1.50‰), whereas hydrothermal veins in the basal ultramafic shear zones preserve magmatic values (~0‰). This study reveals a potential proto-tectonic control on atmospheric, geodynamic and hydrothermal environments available for early sulfate reducing and/or methanogenic microbes in the Paleoarchean.No evidence for microbial sulfate reduction or disproportionation was identified in the Kromberg Cherts, despite previous morphological claims for microbial life. Highly variable and negative δ34SCDT values were found in the Noisy turbidites and Hooggenoeg pillow lava breccia supporting the presence of microbial sulfate reduction in early tectono-sedimentary basins and in the Paleoarchean sub-seafloor, respectively. In light of current controversies surrounding sulfur isotope studies in similar-aged rocks of the Pilbara Craton (West Australia), we argue that microbial elemental sulfur disproportionation was not a preferred metabolic pathway on the Paleoarchean earth. © 2013 Elsevier B.V. Article 2013 English 0012821X 10.1016/j.epsl.2013.06.035 Earth and Planetary Science Letters 377-378 142 – 154 Australia; Barberton Greenstone Belt; Pilbara Block; Western Australia; Biogeochemistry; Gallium; Geodynamics; Isotopes; Pyrites; Quartz; Sedimentology; Sulfur compounds; Tectonics; Disproportionations; Greenstone belts; Hydrothermal environment; Multiple sulfur isotopes; Scientific drilling; Sedimentary environment; Sulfate reduction; Sulfur cycling; anoxic conditions; Archean; atmosphere-biosphere interaction; biogeochemistry; chert; detrital deposit; early Earth; metabasalt; pyrite; seafloor; sulfur cycle; sulfur isotope; tectonics; Sulfur https://www.scopus.com/inward/record.uri?eid=2-s2.0-84883653190&doi=10.1016%2fj.epsl.2013.06.035&partnerID=40&md5=3d893062a8d7e549e43f74d763a289bd Cited by: 16 Eugene G. Grosch Nicola McLoughlin article Jouve2013191 Article 2013 10.1016/j.quascirev.2012.06.003 Quaternary Science Reviews 71 191 – 204 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84878924540&doi=10.1016%2fj.quascirev.2012.06.003&partnerID=40&md5=a6df16e5909b688d8f93c01072037079 Cited by: 59 Guillaume Jouve Pierre Francus Scott Lamoureux Laurence Provencher-Nolet Annette Hahn Torsten Haberzettl David Fortin Laurence Nuttin article Mang20135195 We observed two different Verwey transition temperatures in fragments of crystalline basement rocks and impact sediments from the Chesapeake Bay impact structure, USA. Our study aims to the question if this feature can be used as shock indicator in impact craters. We distinguished three generations of magnetite. (1) Primary magnetite in crystalline basement rocks has average grain sizes up to several hundreds of micrometers and shows a regular TV at ≈ 121 K. (2) Shocked magnetite occurs in fragments of crystalline basement rocks and also in the suevite and impact breccia. These magnetites show two Verwey transitions - a regular one and a "lowerature transition" (LTV) at around 89 K. LTV is related to a small grain size fraction, whereas a larger grain size fraction (some hundreds of micrometers) causes the regular TV. The small grain size fraction contains a distinctly higher amount of superficially oxidized material due to the high surface/volume ratio, which causes a decrease of the Verwey transition temperature (LTV). (3) A secondary magnetite generation shows also two Verwey transition temperatures, one at 121 K and a LTV range between 91 and 105 K. The LTV in this generation is also linked to thin oxidized surface layers. This study shows that especially the Verwey transition temperature of small magnetite grains reacts very sensitively to surface oxidation and can therefore not be used as a reliable pressure indicator for impact structures on Earth. Key Points Reduction of Verwey transition due to nonstoichiometry Degree of nonstoichiometry triggered by grain size Surface/volume ratio crucial for reduction of Verwey transition ©2013. American Geophysical Union. All Rights Reserved. 2013 10.1002/jgrb.50291 Journal of Geophysical Research: Solid Earth 118 5195-5207 Institut für Angewandte Geowissenschaften, Karlsruher Institut für Technologie, Adenauerring 20, Geb. 50.41, Karlsruhe, D-76131, Germany 10 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84889009695&doi=10.1002%2fjgrb.50291&partnerID=40&md5=fb1a878d995dd75640733f1a885e6aaa cited By 9 C. Mang A. Kontny article cp-9-135-2013 2013 10.5194/cp-9-135-2013 Climate of the Past 9 135-148 1 https://cp.copernicus.org/articles/9/135/2013/ V. Wennrich A. Francke A. Dehnert O. Juschus T. Leipe C. Vogt J. Brigham-Grette P. S. Minyuk M. Melles El'gygytgyn Science Party article Morgan20131508 The discovery of large amounts of soot in clays deposited at the Cretaceous-Paleogene (K-Pg) boundary and linked to the ~65 Ma Chicxulub impact crater led to the hypothesis that major wildfires were a consequence of the asteroid impact. Subsequently, several lines of evidence, including the lack of charcoal in North American sites, were used to argue against global wildfires. Close to the impact site fires are likely to be directly ignited by the impact fireball, whereas globally they could be ignited by radiation from the reentry of hypervelocity ejecta. To-date, models of the latter have yet to take into account that ejection - and thus the emission of thermal radiation - is asymmetric and dependent on impact angle. Here, we model: (1) the impact and ejection of material, (2) the ballistic continuation of ejecta around a spherical Earth, and (3) the thermal pulse delivered to the Earth's surface when ejecta reenters the atmosphere. We find that thermal pulses in the downrange direction are sufficient to ignite flora several thousand kilometers from Chicxulub, whereas pulses at most sites in the uprange direction are too low to ignite even the most susceptible plant matter. Our analyses and models suggest some fires were ignited by the impact fireball and ejecta reentry, but that the nonuniform distribution of thermal radiation across the surface of the Earth is inconsistent with the ignition of fires globally as a direct and immediate result of the Chicxulub impact. Instead, we propose that the desiccation of flora by ejecta reentry, as well as the effects of postimpact global cooling/darkness, left much of the terrestrial flora prone to fires, and that the volume of soot in the global K-Pg layer is explained by a combination of syn- and postimpact wildfires. Key Points K-Pg thermal radiation from re-entering ejecta is simulated with a new 3D model Radiation varied with distance and direction from Chicxulub Wildfires were ignited in some directions, but they were not global ©2013. American Geophysical Union. All Rights Reserved. 2013 10.1002/2013JG002428 Journal of Geophysical Research: Biogeosciences 118 1508-1520 Department of Earth Science and Engineering, Imperial College London, South Knesington Campus, London, SW7 2AZ, United Kingdom; Planetary Science Institute, Tucson, AZ, United States; Institute for Dynamics of Geospheres, Moscow, Russian Federation; Department of Lithospheric Research, University of Vienna, Vienna, Austria; Nature Geoscience, Nature Publishing Group, London, United Kingdom 4 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84892945774&doi=10.1002%2f2013JG002428&partnerID=40&md5=82a863c4a5ac336d915367120a2d4e32 cited By 41 J. Morgan N. Artemieva T. Goldin article Kliem2013131 Laguna Potrok Aike is a large maar lake located in the semiarid steppe of southern Patagonia known for its Lateglacial and Holocene lake level fluctuations. Based on sedimentary, seismic and geomorphological evidences, the lake level curve is updated and extended into the Last Glacial period and the geomorphological development of the lake basin and its catchment area is interpreted.Abrasion and lake level oscillations since at least ~50ka caused concentric erosion of the surrounding soft rocks of the Miocene Santa Cruz Formation and expanded the basin diameter by approximately 1km. A high lake level and overflow conditions of the lake were dated by luminescence methods and tephra correlation to the early Lateglacial as well as to ~45ka. The lowest lake level of record occurred during the mid-Holocene. A further lake level drop was probably prevented by groundwater supply. This low lake level eroded a distinct terrace into lacustrine sediments. Collapse of these terraces probably caused mass movement deposits in the profundal zone of the lake. After the mid-Holocene lake level low stand a general and successive transgression occurred until the Little Ice Age maximum; i.e. ca 40m above the local groundwater table. Frequent lake level oscillations caused deflation of emerged terraces only along the eastern shoreline due to prevailing westerly winds. Preservation of eolian deposits might be linked to relatively moist climate conditions during the past 2.5ka.Precisely dated lake level reconstructions in the rain-shadow of the Andes document high Last Glacial and low Holocene lake levels that could suggest increased precipitation during the Last Glacial period. As permafrost in semiarid Patagonia is documented and dated to the Last Glacial period we argue that the frozen ground might have increased surficial runoff from the catchment and thus influenced the water balance of the lake. This is important for investigating the glacial to Holocene latitudinal shift and/or strengthening of the Southern Hemispheric Westerlies by using lake level reconstructions as a means to assess the regional water balance. Our interpretation explains the contradiction with investigations based on pollen data indicating drier climatic conditions for the Last Glacial period. © 2012 Elsevier Ltd. Article 2013 10.1016/j.quascirev.2012.08.023 Quaternary Science Reviews 71 131 – 146 Argentina; Laguna Potrok Aike; Patagonia; Santa Cruz [Argentina]; Catchments; Curve fitting; Deposits; Glacial geology; Groundwater; Permafrost; Rain; Runoff; Salinity measurement; Sedimentary rocks; Soils; Glacial; Holocenes; ICDP-project PASADO; Lacustrine sediments; Lake level fluctuations; Regional water balance; Southern Hemispheric Westerlies; Surrounding soft rock; catchment; data set; geomorphology; groundwater; Last Glacial Maximum; Little Ice Age; luminescence; maar; magnitude; mass movement; Miocene; oscillation; permafrost; precipitation (climatology); semiarid region; Southern Hemisphere; steppe; tephrochronology; transgression; Lakes https://www.scopus.com/inward/record.uri?eid=2-s2.0-84878946242&doi=10.1016%2fj.quascirev.2012.08.023&partnerID=40&md5=911db3958ecb47af674415cbfed3dcf6 Cited by: 33 P. Kliem J.P. Buylaert A. Hahn C. Mayr A.S. Murray C. Ohlendorf D. Veres S. Wastegård B. Zolitschka article Huang2013152 Songliao Basin in NE China developed the most productive oilfield in the world sourced from terrestrial rocks. The main source rock of the basin includes member 1 of the Qingshankou (K2qn1) and members 1 and 2 of the Nenjiang Formation (K2nj1-2). However the exact reasons for the formation of the source rock, especially the K2qn1 are still controversial. Former paleontological and organic geochemical research suggested that organic matter was deposited during marine incursion events of K2qn1 but further geochemical evidence is needed. This paper explores the distinct sulfate levels that distinguish marine from fresh waters of the Songliao paleo-lake. We undertook a systematic investigation the sulfur geochemistry of the sediments from top of member 4 of the Quantou Formation (K1q4) to top of member 1 of the Qingshankou (K2qn1). The ratio of organic carbon to the pyrite sulfur (TOC/PYS) proved the previously suggested saline conditions during the deposition of K2qn1; and the pyrite sulfur isotope indicated that marine incursion may not only have occurred for K2qn1, but also for top of K1q4. The exact time for the beginning of marine incursion is to be determined. The marine incursion within K2qn1 is not strong and partially controlled by the fluctuation of paleo-lake level. The present study will be helpful for understanding the contribution of marine incursion events to the burial of organic carbon in the Songliao paleo-lake, although further studies are still needed. © 2013 Elsevier B.V. 2013 English 00310182 10.1016/j.palaeo.2013.03.017 Palaeogeography, Palaeoclimatology, Palaeoecology 385 152-161 State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing 100083, China; School of the Earth Science and Resources, China University of Geosciences, Beijing 100083, China; School of Engineering and Technology, China University of Geosciences, Beijing 100083, China; Institute of Oil Exploration and Development, Daqing Oilfield Company, Daqing 163712, China; Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China; Oil and Gas Survey, China Geological Survey, Beijing 100029, China Cretaceous; geochemistry; lake level; oil field; organic carbon; paleolimnology; paleontology; source rock; sulfate; sulfur isotope, China; Nen Basin; Songliao Basin https://www.scopus.com/inward/record.uri?eid=2-s2.0-84879881980&doi=10.1016%2fj.palaeo.2013.03.017&partnerID=40&md5=3a2f5470550289e4aeefd23ecd91b6d9 cited By 59 Y. Huang G. Yang J. Gu P. Wang Q. Huang Z. Feng L. Feng article cp-9-1949-2013 This paper focuses on the characterization and genesis of mass movement deposits (MMDs) in the Quaternary and Pliocene sediments of Lake El'gygytgyn, Far East Russian Arctic. Three partly overlapping holes were drilled into the 320 m long sediment record at International Continental Scientific Drilling Program (ICDP) Site 5011-1 in the lake basin, recovering the Quaternary almost completely, and the Pliocene down to 3.6 Ma with 52% recovery. Mass movement deposits were investigated in all three cores, based on macroscopical core descriptions, radiographic images, high-resolution magnetic susceptibility and gamma-ray density. Five different types of MMDs were identified: turbidites, grain-flow deposits, debrites, slumps and slides. These are formed by transitional mass movement processes, and thus can be co-generic. An initial slope failure is thought to transform into a debris flow that deforms frontal sediments, partly disintegrates and dilutes into a turbidity flow. Turbidites are by far the most frequent MMD type in the lake center. They occur throughout the record in all pelagic sedimentary facies, but they are thinner in facies formed during cold climate conditions. All other MMDs, by contrast, incise exclusively the pelagic facies deposited during warm climates. In the 123 m thick Quaternary composite sediment record 230 mass movement events are identified, comprising 33% of the sediment length. Turbidites contribute 93% of the number of Quaternary MMDs, but only 35% of their thickness. In the Pliocene sediments between 123 and 320 m, 181 additional mass movement deposits are identified, which constitute ∼33% of the recovered sediments. The mean recurrence interval for MMDs is 11 and 5 ka in the Quaternary and Pliocene, respectively. © Author(s) 2013. 2013 English 18149324 10.5194/cp-9-1949-2013 Climate of the Past 9 1949-1967 Institute of Geology and Mineralogy, University of Cologne, Zuelpicher Str. 49a, 50674 Cologne, Germany; Eberswalde University of Sustainable Development, Faculty of Landscape Management and Nature Conservation, Eberswalde, Germany; Alfred Wegener Institute for Polar and Marine Research, Bremerhaven, Germany; Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences, Potsdam, Germany 4 debris flow; depositional environment; facies; lacustrine deposit; mass movement; Pliocene; Quaternary; slope failure; turbidite; turbidity, Arctic; Chukchi; Elgygytgyn Lake; Russian Federation https://cp.copernicus.org/articles/9/1949/2013/ cited By 36 M. A. Sauerbrey O. Juschus A. C. Gebhardt V. Wennrich N. R. Nowaczyk M. Melles article Ohlendorf201327 Laguna Potrok Aike is an exceptional site in the southern hemisphere's mid-latitudes because it records changes in the hydrological regime through lake-level variations in a continuous, high-resolution sediment record back into the late Pleistocene. In this study, driving forces of lake-level changes at Laguna Potrok Aike are evaluated by means of process studies using data from an extensive multi-year monitoring in and around the lake. Lake-volume changes were calculated with an energy-budget/bulk-transfer approach and translated into lake-level variations, which were then compared to pressure sensor data. Calculated lake levels are in broad agreement with measured data. We hypothesize that on short time scales, lake-level fluctuations are mainly driven by the precipitation-to-evaporation ratio. Apart from changing catchment conditions, relative humidity, precipitation, temperature, wind strength and wind direction have the most important influence on the hydrological balance of the lake. Lake level decreases during periods of persistently high wind speeds from westerly directions, whereas, during periods with more frequent occurrences of easterly winds, it increases. These situations are linked to a strengthening of the Southern Hemispheric Westerlies in the first and more frequent blocking situations in the latter case. Although lake-level changes at Laguna Potrok Aike show some degree of similarity to variations of the El Niño Southern Oscillation (ENSO) and the Southern Hemisphere Annular Mode (SAM), a persistent correspondence remains to be documented.Water chemistry and sediment-trap data suggest that lake-internal carbonate precipitation is highly sensitive to short-term changes in the lake water volume and, thus, to lake-level variations. However, it becomes obvious that the sedimentary carbonate record, representing changes on longer time scales, is not linearly linked to lake-level changes, hence complicating quantitative lake-level reconstructions back in time. We suggest that short-term changes in authigenic carbonate production are mainly driven by changing precipitation/evaporation ratios probably superimposed on longer-term changes in groundwater input that represent a buffered climate signal.Scenario calculations for a period of 60 years show that changes of the controlling meteorological parameters in the range of 15-17% can lead to lake-level changes with a magnitude comparable to the reconstructed Holocene and Lateglacial extreme situations. In addition, modifications in the water-retaining capacity of the lake can also produce large lake-level changes. It is hypothesized that the development or disappearance of permafrost in the catchment of Laguna Potrok Aike during the Last Glacial/Interglacial transition may have changed the water-retaining capacity tremendously. The lake-level reconstructions for Laguna Potrok Aike might express some of the meridional climate variability observed in coupled general circulation model (CGCM) simulations for southern South America for the Last Glacial Maximum (LGM) and the mid Holocene. © 2012 Elsevier Ltd. Article 2013 10.1016/j.quascirev.2012.10.040 Quaternary Science Reviews 71 27 – 45 Argentina; Laguna Potrok Aike; Santa Cruz [Argentina]; Atmospheric pressure; Carbonation; Catchments; Climatology; Digital storage; Groundwater; Lasers; Monitoring; Runoff; Sediment traps; Sedimentology; Authigenic carbonates; Carbonate precipitation; Coupled general circulation models; ICDP-project PASADO; Meteorological parameters; Southern Hemisphere; Southern hemisphere annular modes; Southern south america; carbonate; energy budget; environmental monitoring; evaporation; general circulation model; hydrochemistry; hydrological change; lacustrine environment; mathematical analysis; permafrost; precipitation (chemistry); sediment chemistry; sediment trap; Southern Hemisphere; timescale; volume; wind velocity; Lakes https://www.scopus.com/inward/record.uri?eid=2-s2.0-84878937235&doi=10.1016%2fj.quascirev.2012.10.040&partnerID=40&md5=2a14220abd360aaca2511814d6ea5fc4 Cited by: 37 Christian Ohlendorf Michael Fey Catalina Gebhardt Torsten Haberzettl Andreas Lücke Christoph Mayr Frank Schäbitz Michael Wille Bernd Zolitschka article Breuker2013578 The investigated deeply buried marine sediments of the shallow shelf off New Jersey, USA, are characterized by low organic carbon content and total cell counts of &lt; 107 cells per mL sediment. The qPCR data for Bacteria and Archaea were in the same orders of magnitude as the total cell counts. Archaea and Bacteria occurred in similar 16S rRNA gene copy numbers in the upper part of the sediments, but Bacteria dominated in the lowermost part of the analyzed sediment cores down to a maximum analyzed depth of c. 50 meters below seafloor (mbsf). The bacterial candidate division JS1 and the classes Anaerolineae and Caldinilineae of the Chloroflexi were almost as highly abundant as the total Bacteria. Similarly high dsrA gene copy numbers were found for sulfate reducers. The abundance of the Fe(III) and Mn(IV) reducers comprising Geobacteraceae in the upper c. 15 mbsf correlated with concentrations of manganese and iron in the pore water. The isolated 16S rRNA gene sequences of Archaea in clone libraries could be allocated to the phyla Thaumarchaeota, Euryarchaeota, and Crenarchaeota with 1%, 14%, and 85%, respectively. The typical deep subsurface sediment-associated groups MBG-B, MBG-D, MCG, and SAGMEG were represented in the sediment community. MCG was the dominant group with a high diversity of the isolated 16S rRNA gene sequences. © 2013 Federation of European Microbiological Societies. 2013 English 01686496 10.1111/1574-6941.12146 FEMS Microbiology Ecology 85 578-592 Bundesanstalt für Geowissenschaften und Rohstoffe, Hannover, Germany 3 RNA 16S, abundance; biosphere; data set; gene; manganese; marine sediment; microbial community; organic carbon; polymerase chain reaction; porewater; seafloor; shallow soil; sulfate, archaeon; article; bacterium; biodiversity; Chloroflexi; classification; Crenarchaeota; deep biosphere; Deltaproteobacteria; Euryarchaeota; genetics; IODP; isolation and purification; microbiology; Miscellaneous Crenarchaeotal Group; phylogeny; sea; sediment; sediments; travel; United States, Crenarchaeota; deep biosphere; Euryarchaeota; IODP; Miscellaneous Crenarchaeotal Group; sediments, Archaea; Bacteria; Biodiversity; Chloroflexi; Crenarchaeota; Deltaproteobacteria; Euryarchaeota; Expeditions; Geologic Sediments; New Jersey; Oceans and Seas; Phylogeny; RNA, Ribosomal, 16S, New Jersey; United States, Anaerolineae; Archaea; Bacteria (microorganisms); Chloroflexi; Chloroflexi (class); Crenarchaeota; Euryarchaeota; Geobacteraceae; Lake Victoria marburgvirus https://www.scopus.com/inward/record.uri?eid=2-s2.0-84881557283&doi=10.1111%2f1574-6941.12146&partnerID=40&md5=d0814b627f919b3645a9f3d5958adcf0 cited By 34 A. Breuker S. Stadler A. Schippers article Chen2013190 Utilizing the Community Climate System Model version 2 from the National Center for Atmospheric Research (NCAR) and the reconstructed paleogeographic data, we simulate East Asian climate in the Late Cretaceous (66Ma) and investigate the impacts of atmospheric CO2 concentration on climate. The simulations show that the large-scale pressure systems and prevailing wind directions showed a remarkable seasonal variation over East Asia at 66Ma, which indicates a monsoon feature over East Asia. The East Asian winter and summer monsoons showed a synchronous variation, that is, a strong (weak) winter monsoon accompanied a strong summer (weak) monsoon. At 66Ma, there was more precipitation over the eastern coasts of Asia and less precipitation in the mid-latitudes of the inland areas, but there was no meiyu rainy belt in the subtropics of the East Asian land like the present climate. Moreover, the simulated Cretaceous climate over East Asia was warmer relative to the present day. Annual mean surface air temperature was higher over Asia at that time and close to the estimation from the geological evidence. In the Late Cretaceous, when atmospheric CO2 concentration is reduced, the East Asia climate has a significant change, with weaker winter and summer monsoons over East Asia. Annual mean surface air temperature and annual total precipitation reduce in most of land and ocean. Negative difference of surface water budget appeared mainly in the eastern part of East Asia, indicating a drier soil surface, while positive differences appeared in the mid-latitudes of central-western Asia, indicating a wetter soil surface. © 2012 Elsevier B.V. 2013 English 00310182 10.1016/j.palaeo.2012.07.017 Palaeogeography, Palaeoclimatology, Palaeoecology 385 190-201 Chinese Academy of Meteorological Sciences, Beijing 100081, China; National Meteorological Information Center, China Meteorological Administration, Beijing 100081, China; Research Center f or Tibetan Plateau Geology, China University of Geosciences (Beijing), Beijing 100083, China; Key Laboratory of Marine Hydrocarbon Resources and Environment Geology, Qingdao Institute of Marine Geology, Qingdao 266071, China air temperature; carbon dioxide; climate effect; climate modeling; climate variation; concentration (composition); Cretaceous; greenhouse gas; monsoon; paleogeography; precipitation (climatology); seasonal variation; water budget; wind direction, Far East https://www.scopus.com/inward/record.uri?eid=2-s2.0-84879878390&doi=10.1016%2fj.palaeo.2012.07.017&partnerID=40&md5=7508108868ed2f3c1220bf84c01509c5 cited By 26 J. Chen P. Zhao C. Wang Y. Huang K. Cao article Xu2013150 The quantification of carbon burial in lake sediments, and carbon fluxes derived from different origins are crucial to understand modern lacustrine carbon budgets, and to assess the role of lakes in the global carbon cycle. In this study, we estimated carbon burial in the sediment of Lake Qinghai, the largest inland lake in China, and the carbon fluxes derived from different origins. We find that: (1) The organic carbon burial rate in lake sediment is approximately 7.23gm-2a-1, which is comparable to rates documented in many large lakes worldwide. We determined that the flux of riverine particulate organic carbon (POC) is approximately 10 times higher than that of dissolved organic carbon (DOC). Organic matter in lake sediments is primarily derived from POC in lake water, of which approximately 80% is of terrestrial origin. (2) The inorganic carbon burial rate in lake sediment is slightly higher than that of organic carbon. The flux of riverine dissolved inorganic carbon (DIC) is approximately 20 times that of DOC, and more than 70% of the riverine DIC is drawn directly and/or indirectly from atmospheric CO2. (3) Both DIC and DOC are concentrated in lake water, suggesting that the lake serves as a sink for both organic and inorganic carbon over long term timescales. (4) Our analysis suggests that the carbon burial rates in Lake Qinghai would be much higher in warmer climatic periods than in cold ones, implying a growing role in the global carbon cycle under a continued global warming scenario. © 2013 Elsevier Ltd. Article 2013 English 08832927 10.1016/j.apgeochem.2013.04.004 Applied Geochemistry 39 150 – 155 China; Qinghai; Qinghai Lake; Carbon; Carbon dioxide; Global warming; Sediments; Climatic periods; Different origins; Dissolved inorganic carbon; Dissolved organic carbon; Global carbon cycle; Inorganic carbon; Organic carbon burial rates; Particulate organic carbon; carbon budget; carbon cycle; global warming; lacustrine deposit; organic carbon; sediment chemistry; Lakes https://www.scopus.com/inward/record.uri?eid=2-s2.0-84888295087&doi=10.1016%2fj.apgeochem.2013.04.004&partnerID=40&md5=9f1d604f396dffc4dfc34b5e5da7300e Cited by: 37 Hai Xu Jianghu Lan Bin Liu Enguo Sheng Kevin M. Yeager article cp-9-335-2013 Stable isotope data from lipid biomarkers and diatom silica recovered from lake sediment cores hold great promise for paleoclimate and paleohydrological reconstructions. However, these records rely on accurate calibration with modern precipitation and hydrologic processes and only limited data exist on the controls on the -D values for nalkanoic acids from plant leaf waxes. Here we investigate the stable isotopic composition of modern precipitation, streams, lake water and ice cover, and use these data to constrain isotope systematics of the Lake El'gygytgyn Basin hydrology. Compound-specific hydrogen isotope ratios determined from n-alkanoic acids from modern vegetation are compared with modern precipitation and lake core top sediments. Multispecies net (apparent) fractionation values between source water (precipitation) and modern vegetation (e.g., quot;wax/precip mean value is ?107±12 ) agree with previous results and suggest a consistent offset between source waters and the -D values of alkanoic acids. We conclude that although there may be some bias towards a winter precipitation signal, overall -D values from leaf wax n-alkanoic acids record annual average precipitation within the El'gygytgyn Basin. A net fractionation calculated for 200-yr-integrated lake sediments yields quot;30/precip = ?968and can provide robust net "apparent" fractionation to be used in future paleohydrological reconstructions. © Author(s) 2013. CC Attribution 3.0 License. 2013 English 18149324 10.5194/cp-9-335-2013 Climate of the Past 9 335-352 Department of Geosciences, University of Massachusetts, Amherst, MA, United States; Alfred Wegener Institute for Polar and Marine Research, Research Unit Potsdam, Potsdam, Germany; University of Toronto, Toronto, Canada 1 biomarker; calibration; diatom; hydrogen isotope; ice cover; isotopic analysis; isotopic composition; isotopic ratio; lacustrine deposit; lipid; paleoclimate; paleohydrology; precipitation (climatology); reconstruction; sediment core; silica; wax, Chukchi; Elgygytgyn Lake; Russian Federation https://cp.copernicus.org/articles/9/335/2013/ cited By 30 K. M. K. Wilkie B. Chapligin H. Meyer S. Burns S. Petsch J. Brigham-Grette article Wennrich2013135 Lake El’gygytgyn/NE Russia holds a continuous 3.58 Ma sediment record, which is regarded as the most long-lasting climate archive of the terrestrial Arctic. Based on multi-proxy geochemical, mineralogical, and granulometric analyses of surface sediment, inlet stream and bedrock samples, supplemented by statistical methods, major processes influencing the modern sedimentation in the lake were investigated. Grain-size parameters and chemical elements linked to the input of feldspars from acidic bedrock indicate a wind-induced two-cell current system as major driver of sediment transport and accumulation processes in Lake El’gygytgyn. The distribution of mafic rock related elements in the sediment on the lake floor can be traced back to the input of weathering products of basaltic rocks in the catchment. Obvious similarities in the spatial variability of manganese and heavy metals indicate sorption or co-precipitation of these elements with Fe and Mn hydroxides and oxides. But the similar distribution of organic matter and clay contents might also point to a fixation to organic components and clay minerals. An enrichment of mercury in the inlet streams might be indicative of neotectonic activity around the lake. The results of this study add to the fundamental knowledge of the modern lake processes of Lake El’gygytgyn and its lake-catchment interactions, and thus, yield crucial insights for the interpretation of paleo-data from this unique archive. © Author(s) 2013. 2013 English 18149324 10.5194/cp-9-135-2013 Climate of the Past 9 Copernicus GmbH 135-148 University of Cologne, Institute for Geology and Mineralogy, Cologne, Germany; Swiss Federal Nuclear Safety Inspectorate ENSI, Brugg, Switzerland; Eberswalde University for Sustainable Development, Eberswalde, Germany; Leibniz Institute for Baltic Sea Research Warnemuende, Marine Geology, Rostock, Germany; University Bremen, Department of Geosciences, Crystallography, ZEKAM, Bremen, Germany; University of Massachusetts, Department of Geosciences, Amherst, United States; Russian Academy of Sciences, Northeast Interdisciplinary Scientific Research Institute, Magadan, Russian Federation 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84883002188&doi=10.5194%2fcp-9-135-2013&partnerID=40&md5=65f5978954a030e1a0250d3d6db7f19d cited By 24 V. Wennrich A. Francke A. Dehnert O. Juschus T. Leipe C. Vogt J. Brigham-Grette P.S. Minyuk M. Melles El'gygytgyn Science Party article Vuillemin2013275 Authigenic minerals can form in the water column and sediments of lakes, either abiotically or mediated by biological activity. Such minerals have been used as paleosalinity and paleoproductivity indicators and reflect trophic state and early diagenetic conditions. They are also considered potential indicators of past and perhaps ongoing microbial activity within sediments. Authigenic concretions, including vivianite, were described in late glacial sediments of Laguna Potrok Aike, a maar lake in southernmost Argentina. Occurrence of iron phosphate implies specific phosphorus sorption behavior and a reducing environment, with methane present. Because organic matter content in these sediments was generally low during glacial times, there must have been alternative sources of phosphorus and biogenic methane. Identifying these sources can help define past trophic state of the lake and diagenetic processes in the sediments. We used scanning electron microscopy, phosphorus speciation in bulk sediment, pore water analyses, in situ ATP measurements, microbial cell counts, and measurements of methane content and its carbon isotope composition (δ13CCH4) to identify components of and processes in the sediment. The multiple approaches indicated that volcanic materials in the catchment are important suppliers of iron, sulfur and phosphorus. These elements influence primary productivity and play a role in microbial metabolism during early diagenesis. Authigenic processes led to the formation of pyrite framboids and revealed sulfate reduction. Anaerobic oxidation of methane and shifts in pore water ion concentration indicated microbial influence with depth. This study documents the presence of active microbes within the sediments and their relationship to changing environmental conditions. It also illustrates the substantial role played by microbes in the formation of Laguna Potrok Aike concretions. Thus, authigenic minerals can be used as biosignatures in these late Pleistocene maar sediments. © 2013 Springer Science+Business Media Dordrecht. Article 2013 10.1007/s10933-013-9723-9 Journal of Paleolimnology 50 275 – 291 3 Argentina; Laguna Potrok Aike; Santa Cruz [Argentina]; diagenesis; environmental conditions; late glacial; maar; metabolism; methane; microbial activity; paleoproductivity; paleosalinity; phosphorus; porewater; pyrite; scanning electron microscopy; sorption; vivianite; water column https://www.scopus.com/inward/record.uri?eid=2-s2.0-84883780186&doi=10.1007%2fs10933-013-9723-9&partnerID=40&md5=9fb78e69d9e1a48f21228ee31af91e8f Cited by: 32; All Open Access, Green Open Access A. Vuillemin D. Ariztegui A.S. De Coninck A. Lücke C. Mayr C.J. Schubert article Hrubcová2013120 The West Bohemia/Vogtland area is known for its increased geodynamic activity with reoccurrence of intraplate earthquake swarms. Previous geophysical studies, namely active and passive seismic investigations, revealed a high velocity lower crust in this area with increased reflectivity. To refine this result and retrieve a more detailed structure of the deep crust and the Moho discontinuity, we analyzed waveforms of local microearthquakes that occurred in this area during the 2008 swarm. The waveforms of earthquakes were grouped into clusters with similar focal mechanisms, and the clusters were processed separately. We developed a new multiazimuthal approach in data processing to increase resolution of Moho phases in the waveforms. We applied the waveform cross-correlation of the P and S waves, and rotated, aligned, and stacked the seismograms to extract the Moho SmS, PmP, and PmS reflected/converted phases. These phases were inverted for laterally varying Moho depth by ray tracing and a grid search inversion algorithm. The model retrieved was verified using modeling of full waveforms computed by the discrete wave number method. The multiazimuthal approach reveals details in the velocity structure of the crust/mantle transition at each station. Instead of a single interface with a sharp velocity contrast, the inversion indicates a reflective zone at Moho depths with one or two strongly reflective interfaces, which is in agreement with the zone interpreted by previous investigations. The thickness of the zone varies from 2 to 4 km within the depth range of 27-31.5 km and is delimited by reflections from its top and bottom boundaries, sometimes with strong reflectors within the zone. The average Vp/Vs ratio determined from the Moho reflections and conversions is 1.73. Key Points Moho topography from waveforms of local microearthquakes New multi-azimuthal approach to reveal details of the crust/mantle transition Combined data processing, ray tracing, discrete wave-number and grid search ©2012. American Geophysical Union. All Rights Reserved. Article 2013 English 21699313 10.1029/2012JB009360 Journal of Geophysical Research: Solid Earth 118 Blackwell Publishing Ltd 120 – 137 1 Bohemia; Bohemian Massif; Czech Republic; Germany; Vogtland; crustal structure; focal mechanism; lower crust; microearthquake; modeling; Moho; P-wave; S-wave; seismicity; velocity structure; waveform analysis https://www.scopus.com/inward/record.uri?eid=2-s2.0-84877110777&doi=10.1029%2f2012JB009360&partnerID=40&md5=498aa8c3e7cc8b556cdf04baa02b0b66 Cited by: 27 Pavla Hrubcová Václav Vavryčuk Alena Boušková Josef Horálek article Morgavi201387 In this work we present the results of time series experiments performed by mixing basaltic and rhyolitic melts at high temperature using a device recently developed to trigger chaotic dynamics in a mixing system. The morphology of mixing patterns is quantified at different times by measuring their fractal dimension and a linear relationship is derived between mixing time and morphological complexity. The complexity of mixing patterns is also compared to the degree of homogenization of chemical elements during mixing and empirical relationships are established between the fractal dimension and the temporal variation of concentration variance of elements.New concepts and tools to study the magma mixing process unfold from the experimental results presented in this work. The first one is that the mixing patterns are fractals and they can be quantified by measuring their fractal dimension. This represents a further step in the quantification of the magma mixing process. The second outcome is that the relationship between the fractal dimension of the mixing patterns and mixing time is linear. This has important volcanological implications as the analyses of the morphology of mixing patterns in volcanic rocks can be complemented by experiments to build a new chronometer to estimate the mixing-to-eruption time. A further result from this work is the relationship between the fractal dimension of mixing patterns and concentration variance of chemical elements. This represents the first morphochemical study in igneous petrology bringing with it the potential to infer the relative mobility of chemical elements during the time progression of mixing by analyzing the morphology of mixing patterns in the rocks. © 2012. 2013 English 03770273 10.1016/j.jvolgeores.2012.12.007 Journal of Volcanology and Geothermal Research 253 87-96 Dept. Earth and Environmental Sciences, Ludwig-Maximilian-University (LMU), Theresienstrasse 41/III, 80333 München, Germany; Dept. Earth Sciences, University of Perugia, Piazza Universitá, 06100 Perugia, Italy Basaltic melts; Chaotic dynamics; Empirical relationships; High temperature; Linear relationships; Magma mixing; Mixing system; Mixing time; Morphological complexity; Relative mobility; Rhyolitic; Rhyolitic melts; Temporal variation; Time-series experiments, Chemical elements; Experiments; Fractal dimension; Fractals; Igneous rocks; Morphology; Petrography, Mixing, basalt; concentration (composition); element mobility; experimental study; high temperature; igneous geochemistry; magma chemistry; mixing ratio; morphometry; rhyolite; temporal variation; volcanology https://www.scopus.com/inward/record.uri?eid=2-s2.0-84872468459&doi=10.1016%2fj.jvolgeores.2012.12.007&partnerID=40&md5=de3cd11af88b4891c6d0e8f7c49c78e6 cited By 17 D. Morgavi D. Perugini C.P. De Campos W. Ertel-Ingrisch D.B. Dingwell article cp-9-2459-2013 Lake El'gygytgyn, located in the Far East Russian Arctic, was formed by a meteorite impact about 3.58 Ma ago. In 2009, the International Continental Scientific Drilling Program (ICDP) at Lake El'gygytgyn obtained a continuous sediment sequence of the lacustrine deposits and the upper part of the impact breccia. Here, we present grain-size data of the past 2.6 Ma. General downcore grain-size variations yield coarser sediments during warm periods and finer ones during cold periods. According to principal component analysis (PCA), the climate-dependent variations in grain-size distributions mainly occur in the coarse silt and very fine silt fraction. During interglacial periods, accumulation of coarser material in the lake center is caused by redistribution of clastic material by a wind-induced current pattern during the ice-free period. Sediment supply to the lake is triggered by the thickness of the active layer in the catchment and the availability of water as a transport medium. During glacial periods, sedimentation at Lake El'gygytgyn is hampered by the occurrence of a perennial ice cover, with sedimentation being restricted to seasonal moats and vertical conduits through the ice. Thus, the summer temperature predominantly triggers transport of coarse material into the lake center. Time series analysis that was carried out to gain insight into the frequency of the grain-size data showed variations predominately on 98.5, 40.6, and 22.9 kyr oscillations, which correspond to Milankovitch's eccentricity, obliquity and precession bands. Variations in the relative power of these three oscillation bands during the Quaternary suggest that sedimentation processes at Lake El'gygytgyn are dominated by environmental variations caused by global glacial-interglacial variations (eccentricity, obliquity), and local insolation forcing and/or latitudinal teleconnections (precession), respectively. ©Author(s) 2013. 2013 English 18149324 10.5194/cp-9-2459-2013 Climate of the Past 9 2459-2470 University of Cologne, Institute for Geology and Mineralogy, Cologne, Germany; Eberswalde University for Sustainable Development, Eberswalde, Germany; University of Massachusetts, Department of Geosciences, Amherst, United States 6 breccia; eccentricity; grain size; lacustrine deposit; meteorite; multivariate analysis; obliquity; principal component analysis; Quaternary; research program; sediment property; teleconnection; time series analysis, Chukchi; Elgygytgyn Lake; Russian Federation https://cp.copernicus.org/articles/9/2459/2013/ cited By 33 A. Francke V. Wennrich M. Sauerbrey O. Juschus M. Melles J. Brigham-Grette article Meyer2013417 The processes of formation and transport of particles in suevite during impact crater formation remain poorly understood. This paper gives a summary of the investigations at the 14.6 Ma old, 25 km wide Nördlinger Ries Crater in Southern Germany, performed during the last years. The suevite of the Ries Crater occurs in three different geological settings: (1) crater suevite in the central crater cavity inside the inner ring, (2) outer suevite on top of the continuous ejecta blanket, and (3) dikes in the crater basement and in displaced megablocks. For suevite genesis, the following processes have been discussed to-date in literature: (1) fall-back of material into the crater and its periphery upon collapse of an ejecta plume, and (2) horizontal transport of ejected material, akin to (a) an impact melt flow, (b) a pyroclastic flow, or (c) initiated by phreatomagmatic explosion. On the basis of geophysical investigations, numerical models, 3D shape fabrics, modal composition, stereometric and geochemical characteristics fi ve stages will be distinguished for the formation and deposition of the Ries Suevite: (1) an early ejecta plume, (2) a phreatomagmatic explosion after a hiatus, (3) a basal, non-erosive pyroclastic surge, (4) a pyroclastic flow, (5) a second ejecta plume with accretionary lapilli. © 2013 E. Schweizerbart'sche Verlagsbuchhandlung, Stuttgart, Germany. 2013 10.1127/1860-1804/2013/0019 Zeitschrift der Deutschen Gesellschaft fur Geowissenschaften 164 417-432 not available, Torstrasse 25, 10119 Berlin, Deutschland, Germany 3 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84884250151&doi=10.1127%2f1860-1804%2f2013%2f0019&partnerID=40&md5=71c0740a0b588a9a0afa71f3fab294fb cited By 2 C. Meyer article Petrosino2013 In 2012 two seismic surveys were carried out in the area of Bagnolifutura (Campi Flegrei, Naples), with the aim of characterizing the properties of the seismic noise during the drilling activity performed in the framework of the Campi Flegrei Deep Drilling Project (CFDDP; https://sites.google.com/site/ cfddpproject/). During the first survey, which was conducted from 2 to 4 April, before the drilling, seven broadband threecomponent seismometers were installed in two different array configurations. The second survey started on November 26, in concomitance with the drilling operations and fluid injection, and ended on December 5, four days after the end of the drilling, when the maximum depth of 502 m was reached. During this period seven broadband and one short-period three-component sensors were installed. A preliminary spectral analysis was performed on samples of seismic noise; moreover the root mean square of the amplitude of the signals and the polarization parameters were calculated. The preliminary results show similar spectral and polarization features for the data of the two surveys, whereas the amplitude of the seismic noise collected during the second survey is greatly influenced by the bad meteorological conditions. As future development experimental site transfer functions from Nakamura's technique and surface wave dispersion from array techniques will be calculated to obtain the shallow crustal structure. The results corresponding to the different phases of the drilling activity will be compared, with the aim of establishing if significant variations of the medium properties have occurred during the experiment. Moreover the recorded signals will be deeply investigated in order to detect the eventual occurrence of microseismicity induced by fluid injection and to define its features. © 2013 INGV Istituto Nazionale di Geofisica e Vulcanologia. Article 2013 English 15902595 Quaderni di Geofisica 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84879623649&partnerID=40&md5=f2e85614dd2549a6f541290a28690461 Cited by: 0 Simona Petrosino Francesca Bianco Antonella Bobbio Mario Castellano Paola Cusano Edoardo Del Pezzo Danilo Galluzzo Mario La Rocca Veronica Maiello article Jovanovska2013237 Lake Ohrid is an important biodiversity hotspot, including diatom diversity and endemism. Numerous, putatively endemic diatom species have been described from the lake, alongside reports of relict taxa otherwise known only as fossils from European Neogene deposits. Diploneis Ehrenberg ex Cleve is considered to be one of the species-rich genera in Lake Ohrid. This study presents a detailed account of Diploneis in Lake Ohrid, providing additional information on some of the infrequently recorded taxa. In addition, sediment core samples from Lake Ohrid were used to provide an historical account of some of the more abundant taxa and to determine the morphological similarity between fossil (core samples) and extant populations. To this end, detailed light and scanning electron microscope observations were carried out to ascertain the identity and describe the morphological variation of Diploneis taxa. As a result, 15 Diploneis taxa from Lake Ohrid are reported with four potentially endemic species described as new: D. parabudayana, D. rotunda, D. pulchra and D. vetusa. Among the remaining taxa, two endemic species (D. heisingeriae Jurilj and D. tavcharii Jurilj) previously described from Lake Ohrid were observed, along with nine widespread species commonly reported throughout Europe and elsewhere. © 2013 The International Society for Diatom Research. Article 2013 English 21598347 10.1080/0269249X.2013.797219 Diatom Research 28 237 – 262 3 Lake Ohrid; biodiversity; diatom; endemic species; endemism; fossil record; new species; sediment core; taxonomy https://www.scopus.com/inward/record.uri?eid=2-s2.0-84885449211&doi=10.1080%2f0269249X.2013.797219&partnerID=40&md5=17563a29f28c503f81ce9506dd5603cc Cited by: 20 Elena Jovanovska Teofil Nakov Zlatko Levkov article Pavlov20131 This study provides an evaluation of the diversity and distribution of taxa belonging to the genus Hippodonta (Bacillariophyceae) in selected ancient lakes from different geographical regions of the world. The lakes considered are: Lakes Ohrid, Prespa and Dojran from Macedonia, Lake Tanganyika, Tanzania, Lake Turkana, Kenya and Lake Baikal, Russia. In total, there are 34 Hippodonta taxa. Of these, 21 are described as new, 20 species and one variety. The primary morphological features of each taxon are provided and formal descriptions are given for all new taxa. The distinctive characters distinguishing similar taxa are noted. The genus is most diverse in Lake Baikal with 13 taxa, of which four are described as new species (Hippodonta acuta, H. certa, H. communis and H. pulchra). Lake Tanganyika has six taxa, all of which are described as new (H. angustata, H. avittatiformis, H. cocquytiae, H. conspicua, H. crassa and H. radiata). Lake Turkana has only one taxon, also described as new (H. minuta). In the Macedonian old tectonic lakes, seven taxa were found in Lake Ohrid, with five described as new (H. abunda, H. humboldtiana, H. latelanceolata, H. naviculiformis and H. subrostrata), five taxa were found in Lake Prespa, all of which are described as new (H. affinis, H. costulatiformis var. densistriata, H. exigua, H. media and H. rostratoides), and three known taxa were found in Lake Dojran. © 2013 Magnolia Press. Article 2013 English 11793163 10.11646/phytotaxa.90.1.1 Phytotaxa 90 1 – 53 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84878148827&doi=10.11646%2fphytotaxa.90.1.1&partnerID=40&md5=451b5cb7ec773befd22a37f0ab35a2d0 Cited by: 23 Aleksandar Pavlov Zlatko Levkov David M. Williams Mark B. Edlund article cpd-9-6255-2013 2013 10.5194/cpd-9-6255-2013 Climate of the Past Discussions 9 6255-6285 https://cp.copernicus.org/preprints/9/6255/2013/ G. Schwamborn L. Schirrmeister B. Diekmann article Sears20131733 In this interview, Dieter Stöffler (Fig. 1) describes how his interest in meteorites and impact craters dates from his Ph.D. studies at the University of Tübingen when it was learned that the Ries crater was formed by impact. A paper by Dieter's advisor, Wolf von Engelhardt, also triggered an interest in meteorites. After graduation, Dieter helped to establish a laboratory for high pressure mineralogy and he examined rocks from the Ries crater, which led to the concept of progressive shock metamorphism. The group also worked on newly returned Apollo samples and guided astronauts over the crater. A year at the NASA Ames Research Center taught Dieter about experimental impact research with a light-gas gun. After a few more years at Tübingen, Dieter obtained a professorship at the University of Münster where he created the Institute of Planetology, got involved in planning space missions including comet sample return, and continued high pressure mineralogy in collaboration with colleagues in Freiburg. Through several decades of research, Dieter and colleagues have documented the effects of shock on all the major rock-forming minerals and devised widely accepted schemes for the classification of shocked rocks. After the unification of Germany, Dieter became Director of the Natural History Museum in Berlin, during which he made much progress rebuilding the laboratories and the collections. Dieter also helped to create a museum and research center in the Ries crater. He received the Barringer Award of the Meteoritical Society in 1994 and several prestigious awards in Germany. © 2013 The Meteoritical Society. 2013 10.1111/maps.12179 Meteoritics and Planetary Science 48 1733-1751 Space Science and Astrobiology Division, NASA Ames Research Center/Bay Area Environmental Research Institute, MS245-3, Moffett Field, Mountain View, CA 94035, United States 9 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84884939978&doi=10.1111%2fmaps.12179&partnerID=40&md5=bedd7a92e95d42fc7df9e92dd435dabc cited By 0 D.W.G. Sears article Bischoff2013305 In order to investigate the link between the methane dynamics in permafrost deposits and climate changes in the past, we studied the abundance, composition, and methane production of methanogenic communities in Late Pleistocene and Holocene sediments of the Siberian Arctic. We detected intervals of increased methane concentrations in Late Pleistocene and Holocene deposits along a 42 ka old permafrost sequence from Kurungnakh Island in the Lena Delta (northeast Siberia). Increased amounts of archaeal life markers (intact phospholipid ethers) and a high variety in genetic fingerprints detected by 16S ribosomal ribonucleic acid gene analyses of methanogenic archaea suggest presently living and presumably active methanogenic archaea in distinct layers predominantly in Holocene deposits, but also in deep frozen ground at 17 m depth. Potential methanogenic activity was confirmed by incubation experiments. By comparing methane concentrations, microbial incubation experiments, gene analysis of methanogens, and microbial life markers (intact phospholipid esters and ethers) to already partly degraded membrane lipids, such as archaeol and isoprenoid glycerol dialkyl glycerol tetraethers, we demonstrated that archaeol likely represents a signal of past methanogenic archaea. The archaeol signal was used to reconstruct the response of methanogenic communities to past temperature changes in the Siberian Arctic, and the data suggest higher methane emissions occurred during warm periods, particularly during an interval in the Late Pleistocene and during the Holocene. This new data on present and past methanogenic communities in the Siberian terrestrial permafrost imply that these microorganisms will respond to the predicted future temperature rise in the Arctic with increasing methane production, as demonstrated in previous warmer periods. ©2012. American Geophysical Union. All Rights Reserved. 2013 English 08866236 10.1029/2011GB004238 Global Biogeochemical Cycles 27 305-317 Research Department Potsdam, Alfred Wegener Institute for Polar and Marine Research, Potsdam, Germany; Helmholtz Center Potsdam, GFZ German Research Center for Geosciences, Section 4.3 Organic Geochemistry, Potsdam, Germany; Helmholtz Zentrum München, Research Unit for Environmental Genomics, Oberschleissheim, Germany; Tyumen State Oil and Gas University, Tyumen, Russian Federation; Newcastle University, School of Civil Engineering and Geosciences, Newcastle Upon Tyne, NE1 7RU, United Kingdom; Research Institute of Organic Agriculture (FiBL), Soil Sciences Division, Frick, Switzerland; Helmholtz Center Potsdam, GFZ German Research Center for Geosciences, Section 4.5 Geomicrobiology, Potsdam, Germany 2 Genetic fingerprints; Holocene climate change; Lipid biomarkers; Methane concentrations; Methanogenic activity; Methanogenic archaea; Methanogenic community; Temperature changes, Deposits; Ethers; Experiments; Genes; Glycerol; Methanation; Methane; Methanogens; Permafrost; Phospholipids; RNA; Sediments; Soils, Climate change, biomarker; climate variation; concentration (composition); Holocene; lipid; methane; methanogenesis; paleoclimate; permafrost; Pleistocene; prokaryote, Arctic; Kurungnakh Island; Lena Delta; Russian Federation; Sakha; Siberia https://www.scopus.com/inward/record.uri?eid=2-s2.0-84881089394&doi=10.1029%2f2011GB004238&partnerID=40&md5=e080e2ebe5fea500ba086c945ebbfbf4 cited By 39 J. Bischoff K. Mangelsdorf A. Gattinger M. Schloter A.N. Kurchatova U. Herzschuh D. Wagner article meng2013magnetopolarity 2013 Journal of Stratigraphy 37 139-143 2 QA Meng QH Huang XQ Wan CL Deng HY He article Stöffler2013515 We report results of an interdisciplinary project devoted to the 26 km-diameter Ries crater and to the genesis of suevite. Recent laboratory analyses of "crater suevite" occurring within the central crater basin and of "outer suevite" on top of the continuous ejecta blanket, as well as data accumulated during the past 50 years, are interpreted within the boundary conditions imposed by a comprehensive new effort to model the crater formation and its ejecta deposits by computer code calculations (Artemieva et al. 2013). The properties of suevite are considered on all scales from megascopic to submicroscopic in the context of its geological setting. In a new approach, we reconstruct the minimum/maximum volumes of all allochthonous impact formations (108/116 km3), of suevite (14/22 km3), and the total volume of impact melt (4.9/8.0 km3) produced by the Ries impact event prior to erosion. These volumes are reasonably compatible with corresponding values obtained by numerical modeling. Taking all data on modal composition, texture, chemistry, and shock metamorphism of suevite, and the results of modeling into account, we arrive at a new empirical model implying five main consecutive phases of crater formation and ejecta emplacement. Numerical modeling indicates that only a very small fraction of suevite can be derived from the "primary ejecta plume," which is possibly represented by the fine-grained basal layer of outer suevite. The main mass of suevite was deposited from a "secondary plume" induced by an explosive reaction ("fuel-coolant interaction") of impact melt with water and volatile-rich sedimentary rocks within a clast-laden temporary melt pool. Both melt pool and plume appear to be heterogeneous in space and time. Outer suevite appears to be derived from an early formed, melt-rich and clast-poor plume region rich in strongly shocked components (melt ≫ clasts) and originating from an upper, more marginal zone of the melt pool. Crater suevite is obviously deposited from later formed, clast-rich and melt-poor plumes dominated by unshocked and weakly shocked clasts and derived from a deeper, central zone of the melt pool. Genetically, we distinguish between "primary suevite" which includes dike suevite, the lower sublayer of crater suevite, and possibly a basal layer of outer suevite, and "secondary suevite" represented by the massive upper sublayer of crater suevite and the main mass of outer suevite. © The Meteoritical Society, 2013. 2013 10.1111/maps.12086 Meteoritics and Planetary Science 48 515-589 Museum für Naturkunde, Leibniz Institute for Research on Evolution and Biodiversity, Invalidenstraße 43, Berlin, D-10115, Germany; Humboldt-Universität zu Berlin, Unter den Linden 6, Berlin, D-10099, Germany; Russian Academy of Sciences, Institute for the Dynamics of Geospheres, Leninskii prosp. 38/6, Moscow, 117334, Russian Federation; Planetary Science Institute, 1700 E. Fort Lowell Rd. #106, Tucson, AZ, 85719, United States 4 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84876415232&doi=10.1111%2fmaps.12086&partnerID=40&md5=60f7fd85850d8913147c41f8141cc552 cited By 121 D. Stöffler N.A. Artemieva K. Wünnemann W.U. Reimold J. Jacob B.K. Hansen I.A.T. Summerson article Morgavi2013615 We present the first set of chaotic mixing experiments performed using natural basaltic and rhyolitic melts. The mixing process is triggered by a recently developed apparatus that generates chaotic streamlines in the melts, mimicking the development of magma mixing in nature. The study of the interplay of physical dynamics and chemical exchanges between melts is carried out performing time series mixing experiments under controlled chaotic dynamic conditions. The variation of major and trace elements is studied in detail by electron microprobe and Laser Ablation ICP-MS. The mobility of each element during mixing is estimated by calculating the decrease in the concentration variance in time. Both major and trace element variances decay exponentially, with the value of exponent of the exponential function quantifying the element mobility. Our results confirm and quantify how different chemical elements homogenize in the melt at differing rates. The differential mobility of elements in the mixing system is considered to be responsible for the highly variable degree of correlation (linear, nonlinear, or scattered) of chemical elements in many published inter-elemental plots. Elements with similar mobility tend to be linearly correlated, whereas, as the difference in mobility increases, the plots become progressively more nonlinear and/or scattered. The results from this study indicate that the decay of concentration variance is in fact a robust tool for obtaining new insights into chemical exchanges during mixing of silicate melts. Concentration variance is (in a single measure) an expression of the influence of all possible factors (e.g., viscosity, composition, and fluid dynamic regime) controlling the mobility of chemical elements and thus can be an additional petrologic tool to address the great complexity characterizing magma mixing processes. © 2013 Springer-Verlag Berlin Heidelberg. 2013 English 00107999 10.1007/s00410-013-0894-1 Contributions to Mineralogy and Petrology 166 615-638 Department of Earth and Environmental Sciences, Ludwig-Maximilian-University (LMU), Theresienstrasse 41/III, 80333 Munich, Germany; Department of Earth Sciences, University of Perugia, Piazza Universitá, 06100 Perugia, Italy 2 chaotic dynamics; concentration (composition); element mobility; experimental study; magma chemistry; mixing; rhyolite; tectonic evolution; tectonic setting; time series analysis https://www.scopus.com/inward/record.uri?eid=2-s2.0-84880638818&doi=10.1007%2fs00410-013-0894-1&partnerID=40&md5=a4d1c0154874ef8e89844585677fcfde cited By 37 D. Morgavi D. Perugini C.P. Campos W. Ertel-Ingrisch D.B. Dingwell article Goderis20131296 The geochemical nature of the impactites from International Continental Scientific Drilling Project-El'gygytgyn lake drill core 1C is compared with that of impact melt rock fragments collected near the western rim of the structure and literature data. Concentrations of major and trace elements, with special focus on siderophile metals Cr, Co, Ni, and the platinum group elements, and isotope ratios of osmium (Os), were determined to test the hypothesis of an ureilite impactor at El'gygytgyn. Least squares mixing calculations suggest that the upper volcanic succession of rhyolites, dacites, and andesites were the main contributors to the polymict impact breccias. Additions of 2-13.5 vol% of basaltic inclusions recovered from drill core intervals between 391.6 and 423.0 mblf can almost entirely account for the compositional differences observed for the bottom of a reworked fallout deposit at 318.9 mblf, a polymict impact breccia at 471.4 mblf, and three impact melt rock fragments. However, the measured Os isotope ratios and slightly elevated PGE content (up to 0.262 ng g-1 Ir) of certain impactite samples, for which the CI-normalized logarithmic PGE signature displays a relatively flat (i.e., chondritic) pattern, can only be explained by the incorporation of a small meteoritic contribution. This component is also required to explain the exceptionally high siderophile element contents and corresponding Ni/Cr, Ni/Co, and Cr/Co ratios of impact glass spherules and spherule fragments that were recovered from the reworked fallout deposits and from terrace outcrops of the Enmyvaam River approximately 10 km southeast of the crater center. Mixing calculations support the presence of approximately 0.05 wt% and 0.50-18 wt% of ordinary chondrite (possibly type-LL) in several impactites and in the glassy spherules, respectively. The heterogeneous distribution of the meteoritic component provides clues for emplacement mechanisms of the various impactite units. © The Meteoritical Society, 2013. 2013 English 10869379 10.1111/maps.12047 Meteoritics and Planetary Science 48 1296-1324 Department of Geology, Earth System Science, Vrije Universiteit Brussel, Pleinlaan 2, Brussels, BE-1050, Belgium; Department of Analytical Chemistry, Ghent University, Krijgslaan 281-S12, Ghent, BE-9000, Belgium; Department of Earth and Planetary Sciences, Washington University St. Louis, Campus Box 1169, 1 Brookings Dr., St. Louis, MO, 63130-4899, United States; Lunar and Planetary Institute, 3600 Bay Area Blvd., Houston, TX, 77058, United States; Department of Geology and Geophysics, University of Hawaii at Manoa, Honolulu, HI, United States; Department of Geology and Soil Sciences, Ghent University, Krijgslaan 281-S8, Ghent, BE-9000, Belgium; School of Agricultural, Earth and Environmental Sciences, University of KwaZulu-Natal, Durban, South Africa; Institut für Planetologie, Westfälische Wilhelms-Universität Münster, Wilhelm-Klemm-Str. 10, Münster, D-48149, Germany 7 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84880159710&doi=10.1111%2fmaps.12047&partnerID=40&md5=df03802e99801688dea1e0c663fc3ae8 cited By 15 S. Goderis A. Wittmann J. Zaiss M. Elburg G. Ravizza F. Vanhaecke A. Deutsch P. Claeys article Shashidhar20131345 The 14 April 2012 earthquake of Mw 4.8 is the best monitored event in the Koyna region, a globally significant site of reservoir triggered seismicity in western India. Hence, investigation of this event assumes great importance, also considering its epicentral location close to that of the 1967 Koyna earthquake of M 6.3, the world's largest reservoir triggered earthquake. Inversion of P-wave amplitude data along with the first motion polarities at 30 digital seismic stations provides a well-constrained strike-slip type focal mechanism solution, similar to that of the 1967 earthquake. The mechanism is further confirmed by moment tensor inversion of 3-component waveform data recorded at the three nearest broadband stations. The depth distribution of the aftershocks clearly delineates a NNE-SSW trending fault plane dipping about 78° to the WNW and coinciding with the trend of the Donachiwada fault, as well as the left-lateral fault plane of the focal mechanism solution obtained. The precise location, focal mechanism and the seismicity distribution from our dense network indicate that the activity in the Koyna region is mainly controlled by the NNE-SSW trending Donachiwada (D) fault zone rather than the Koyna River Fault Zone (KRFZ) on the west as suggested previously. © 2013 Springer Science+Business Media Dordrecht. 2013 English 13834649 10.1007/s10950-013-9396-x Journal of Seismology 17 1345-1353 National Geophysical Research Institute (CSIR-NGRI), Uppal Road, Hyderabad, 500007, India; National Disaster Management Authority (NDMA), New Delhi, 110029, India 4 active fault; aftershock; earthquake event; fault zone; focal mechanism; moment tensor; reservoir-induced seismicity; seismotectonics, India; Koyna; Maharashtra; Warna https://www.scopus.com/inward/record.uri?eid=2-s2.0-84885035914&doi=10.1007%2fs10950-013-9396-x&partnerID=40&md5=76610c4f195e6874e8139b377b542fd5 cited By 18 D. Shashidhar N.P. Rao D. Srinagesh H. Gupta H.V.S. Satyanarayana G. Suresh A. Satish article Lin2025 Article 2013 Jilin Geology 32 1-6 04 B. Zhao Y. Wang D. Wu Y. Hang conference Blackwell2013117 The geothermal industry has been referred to as "mature" because of the length of time the industry has been producing electricity and the level of technology involved in projects. The same could have been stated about the oil and gas industry in the early 2000's. Yet both industries are continuously trying to advance through research involving resource understanding, technology advances, and technique development. The shale gas play is an outcome of this advancement by the oil and gas industry, taking approximately 20 years to reach the current level of intensive and successful development characterized by using uniform techniques and standards applied to broad areas of similar resource types. In the geothermal industry Enhanced Geothermal Systems (EGS) have been conceptualized for over 40 years and are now starting the initial development phase in a few sites worldwide. Geothermal Energy could follow a track analogous to the oil and gas industry and reach large scale development in 20 years if it learns from the shale play process and addresses the key factors that will enable it to succeed on a large scale. The factors are related to identifying and characterizing the large-scale thermal resources in the upper 3 to 4 km and developing the ability to access the heat-in-place. Accessing the heat in place includes a grid to transport the energy to market and a supply of water. For near-term successful research and development these crucial factors must be maximized. This paper addresses the locations where EGS research and development activities might be optimal over the near term to facilitate development over the longer term. 2013 English 9781629932859 01935933 Transactions - Geothermal Resources Council 37 117-122 Huffington Department of Earth Sciences, Southern Methodist University, Dallas, TX, United States PART 1 EGS; Enhanced geothermal systems; Gulf coast; Haynesville shales; Raton Basin; Shale gas; Snake river plains, Cascades (fluid mechanics); Gas industry; Geothermal fields; Geothermal wells; Research, Shale https://www.scopus.com/inward/record.uri?eid=2-s2.0-84897632772&partnerID=40&md5=1808dff8dc8665daeb5d74ae4c7c772b cited By 5 D. Blackwell Z. Frone M. Richards article Zhu2013205 An investigation of stable isotope (δ13CTOC and δ15NTN) and elemental parameters (TOC, TN contents and TOC/TN ratios) of bulk organic matter (<200μm) from sediment cores recovered from the Patagonian lake Laguna Potrok Aike (Argentina) in the framework of the ICDP deep drilling project PASADO provided insights into past changes in lake primary productivity and environmental conditions in South Patagonia throughout the last Glacial-Interglacial transition. Stratigraphically constrained cluster analyses of all proxy parameters suggest four main phases. From ca 26,100 to 17,300cal.yearsBP, lacustrine phytoplankton was presumably the predominant organic matter source in an aquatic environment with low primary productivity rates. At around 17,300cal.years BP, abrupt and distinct shifts of isotopic and elemental values indicate that the lacustrine system underwent a rapid reorganization. Lake primary productivity (phytoplankton and aquatic macrophytes) shows higher levels albeit with large variations during most of the deglaciation until 13,000cal.yearsBP. The main causes for this development can be seen in improved growing conditions for primary producers because of deglacial warming in combination with expedient availability of nutrients and likely calm wind conditions. After 13,000cal.yearsBP, decreased δ13CTOC values, TOC, TN contents and TOC/TN ratios indicate that the lake approached a new state with reduced primary productivity probably induced by unfavourable growing conditions for primary producers like strengthened winds and reduced nutrient availability. The steady increase in δ15NTN values presumably suggests limitation of nitrate supply for growth of primary producers resulting from a nutrient shortage after the preceding phase with high productivity. Nitrate limitation and consequent decreased lacustrine primary productivity continued into the early Holocene (10,970-8400cal.yearsBP) as reflected by isotopic and elemental values. © 2012 Elsevier Ltd. Article 2013 10.1016/j.quascirev.2012.05.025 Quaternary Science Reviews 71 205 – 218 Argentina; Laguna Potrok Aike; Patagonia; Santa Cruz [Argentina]; Biogeochemistry; Biological materials; Cluster analysis; Isotopes; Lakes; Nitrates; Nutrients; Organic compounds; Photosynthesis; Sedimentology; ICDP; Lake sediments; Last deglaciation; PASADO; Primary productivity; South America; Stable carbon and nitrogen isotopes; carbon isotope; cluster analysis; deglaciation; environmental conditions; glacial-interglacial cycle; growing season; Last Glacial Maximum; macrophyte; nitrogen isotope; organic matter; phytoplankton; primary production; proxy climate record; sediment chemistry; sediment core; stable isotope; Phytoplankton https://www.scopus.com/inward/record.uri?eid=2-s2.0-84878919582&doi=10.1016%2fj.quascirev.2012.05.025&partnerID=40&md5=1e5f4e5972bba6b56bf43621978db9ff Cited by: 16 Jiayun Zhu Andreas Lücke Holger Wissel Daniela Müller Christoph Mayr Christian Ohlendorf Bernd Zolitschka article Flemings201351 2013 English 18168957 10.5194/sd-15-51-2013 Scientific Drilling Copernicus GmbH 51-56 Jackson School of Geosciences, The University of Texas at Austin, 1 University Station C1100, Austin, TX 78712-0254, United States; Pettigrew Engineering, 479 Nine Mile Road, Milam TX 75959, United States; Borehole Research Group, Lamont-Doherty Earth Observatory of Columbia University, P.O. Box 1000, 61 Route 9W, Palisades, NY 10964, United States; Integrated Ocean Drilling Program, Texas A and M University, 1000 Discovery Drive, College Station, TX 77845-9547, United States; Stress Engineering Services, 13800 Westfair East Drive, Houston, TX 77041, United States; Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, United States 15 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84877831178&doi=10.5194%2fsd-15-51-2013&partnerID=40&md5=9e6fb01348c07c907e97d2ea599acf43 cited By 1 P.B. Flemings P.J. Polito T.L. Pettigrew G.J. Iturrino E. Meissner R. Aduddell D.L. Brooks C. Hetmaniak D. Huey J.T. Germaine R.D. Norris P.A. Wilson P. Blum A. Fehr C. Agnini A. Bornemann S. Boulila P.R. Bown C. Cournede O. Friedrich A.K. Ghosh P.M. Hull K. Jo C.K. Junium M. Kaneko D. Liebrand P.C. Lippert Z. Liu H. Matsui K. Moriya H. Nishi B.N. Opdyke D. Penman B. Romans H.D. Scher P. Sexton H. Takagi S.K. Turner J.H. Whiteside T. Yamaguchi Y. Yamamoto conference Uchida2013 A better understanding of the behavior of hydrate-bearing sediments during gas extraction is a vital step towards realization of commercially viable gas production for the future. In 2007, the world first trial of gas production from hydrate-bearing sediments by depressurization method was conducted at the Mallik gas hydrate site, located in the Mackenzie Delta of Northwest Territories, Canada. However, the operation encountered a large amount of sand migration into the well, a phenomenon known as sand production, and thus was terminated after 24 hours. This incident highlights the importance of development of hydro-mechanical sand production model within hydrate-bearing sediments and understanding of the behavior of hydrate-bearing sediments with the effect of sand production during gas extraction. This extended abstract provides a formulation for the sand production including grain flow and hydraulic dispersion effect. A formulation is fully-coupled such that the sand production affects fluid pressures, saturations and temperature. In addition, the effective stress reduction due to grain detachment is incorporated. This results in further deformation of hydrate-bearing sediments, which may need to be considered for stability of the wellbore. 2013 English International Workshop on Geomechanics and Energy: The Ground as Energy Source and Storage European Association of Geoscientists and Engineers, EAGE Technion - Israel Institute of Technology, Israel; Japan Oil, Gas and Metals National Corporation, Japan Bearings (machine parts); Extraction; Geomechanics; Hydration; Production engineering; Sand; Sediments, Depressurization methods; Dispersion effect; Effective stress; Extended abstracts; Further deformations; Gas extractions; Gas productions; Hydro-mechanical, Gas hydrates https://www.scopus.com/inward/record.uri?eid=2-s2.0-84897016224&partnerID=40&md5=a3e981911e0c50370e57012ca7df283e cited By 15 S. Uchida A. Klar Z. Charas K. Yamamoto article Tietze2013130 3-D inversion techniques have become a widely used tool in magnetotelluric (MT) data interpretation. However, with real data sets, many of the controlling factors for the outcome of 3-D inversion are little explored, such as alignment of the coordinate system, handling and influence of data errors and model regularization. Here we present 3-D inversion results of 169 MT sites from the central San Andreas Fault in California. Previous extensive 2-D inversion and 3-D forward modelling of the data set revealed significant along-strike variation of the electrical conductivity structure. 3-D inversion can recover these features but only if the inversion parameters are tuned in accordance with the particularities of the data set. Based on synthetic 3-D data we explore the model space and test the impacts of a wide range of inversion settings. The tests showed that the recovery of a pronounced regional 2-D structure in inversion of the complete impedance tensor depends on the coordinate system. As interdependencies between data components are not considered in standard 3-D MT inversion codes, 2-D subsurface structures can vanish if data are not aligned with the regional strike direction. A priori models and data weighting, that is, how strongly individual components of the impedance tensor and/or vertical magnetic field transfer functions dominate the solution, are crucial controls for the outcome of 3-D inversion. If deviations from a prior model are heavily penalized, regularization is prone to result in erroneous and misleading 3-D inversion models, particularly in the presence of strong conductivity contrasts. A 'good' overall rms misfit is often meaningless or misleading as a huge range of 3-D inversion results exist, all with similarly 'acceptable' misfits but producing significantly differing images of the conductivity structures. Reliable and meaningful 3-D inversion models can only be recovered if data misfit is assessed systematically in the frequency-space domain. © The Authors 2013 Published by Oxford University Press on behalf of The Royal Astronomical Society. 2013 English 0956540X 10.1093/gji/ggt234 Geophysical Journal International 195 130-147 Helmholtz Centre Potsdam, German Research Centre for Geosciences-GFZ, Potsdam, Germany 1 Continental margins: transforms; Crustal structure; Geomagnetic induction; Inverse theory; Magnetotelluric; North America, Data processing; Electric conductivity; Geomagnetism; Magnetotellurics; Recovery; Strike-slip faults; Structural geology; Tensors, Three dimensional, continental margin; crustal structure; data inversion; electrical conductivity; fault zone; geomagnetic field; magnetotelluric method; three-dimensional modeling, California; San Andreas; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-84885760220&doi=10.1093%2fgji%2fggt234&partnerID=40&md5=6de304a1ceb0b77d5fa8aede272cf1a2 cited By 87 K. Tietze O. Ritter article Růzek20131251 In this paper, we present a smooth 3-D seismic model WB2012 for theWest Bohemia/Vogtland earthquake swarm region derived by means of seismic tomography. Inverted data were represented by a set of 2920 P-wave traveltimes from controlled shots fired in a framework of different experiments and a set of 11339 P- and S-wave arrival times from 661 local earthquakes between 1991 December and 2010 March. We used a standard tomographic approach for independent calculation of P- and S-wave velocity fields in a rectangular grid whose size was 1 km in all coordinates. The traveltimes and rays were calculated by a numerical solution of the eiconal equation. While locating seismic events, our new WB2012 model yielded arrival time residuals on average by 13 per cent lower and hypocentre depths by 0.95 km shallower compared to the locations of the foci in the standard 1-D vertically inhomogeneous isotropic velocity model of the West Bohemia swarm region WB2005. Further, we converted the Pand S-wave velocities to the bulk modulus K and Poisson's ratio ν. The bulk modulus (~40- 70 GPa) correlates acceptably with the tectonic and geological structure of the area. The anomalously low values of the Poisson's ratio (~0.15) are typical for the most active focal zones of Nový Kostel and Lazy in West Bohemia. © The Authors 2013. Published by Oxford University Press on behalf of The Royal Astronomical Society. Article 2013 English 1365246X 10.1093/gji/ggt295 Geophysical Journal International 195 1251 – 1266 2 Bohemia; Czech Republic; Germany; Vogtland; Earthquakes; Elastic moduli; Poisson ratio; Seismic waves; Seismographs; Shear waves; Velocity; Wave propagation; Body waves; Controlled-source seismologies; Crustal structure; Europe; Seismic tomography; arrival time; body wave; bulk modulus; crustal structure; earthquake hypocenter; earthquake swarm; isotropy; P-wave; Poisson ratio; S-wave; seismic data; seismic source; seismic tomography; seismic velocity; seismic zone; seismology; tectonic setting; three-dimensional modeling; Three dimensional https://www.scopus.com/inward/record.uri?eid=2-s2.0-84885811978&doi=10.1093%2fgji%2fggt295&partnerID=40&md5=2d75e5c95ca7f10a63de9a2fb38ac9be Cited by: 17; All Open Access, Bronze Open Access Bohuslav Růžek Josef Horálek article Heubeck2013236 Thin and largely discontinuous volcanic tuff beds in the alluvial, fluvial, and marginal-marine siliciclastic strata of the Middle Archaean Moodies Group, Barberton Greenstone Belt (BGB), contain rare to abundant zircon. Dating of magmatic zircon grains from five tuff beds and one cross-cutting dike yield ages which span the entire spectrum of BGB history from ca. 3550. Ma to 3215. Ma and show variable degrees of post-depositional alteration until ca. 2500. Ma. The youngest pristine zircon grains in all tuff samples analyzed by CA-ID-TIMS (Chemical-Abrasion Ion-Dissolution Thermal Ion Mass Spectrometry) yield upper intercept and Concordia ages between 3227.6. ±. 0.3 and 3216. ±. 0.3. Ma, and those grains analyzed by LA-SF-ICP-MS (Laser Ablation-Sector Field-Inductively Coupled Plasma-Mass Spectrometry) and SHRIMP (Sensitive High-Resolution Ion Microprobe) yield ages between 3228. ±. 9 and 3214. ±. 9. Ma. Most of these ages are either identical (within error) or significantly older than a CA-ID-TIMS age of 3223.4. ±. 0.3. Ma, obtained from zircon grains of a tuff horizon of the Schoongezicht Formation at the top of the underlying Fig Tree Group. We interpret this age to mark the time of volcanic eruption, whereas the significantly older and overlapping ages of the stratigraphically higher Moodies tuff zircon grains point either to a high degree of magmatic inheritance and/or a detrital contribution from surrounding sedimentary rocks during or after ash-tuff deposition. The minimum age for deposition of Moodies Group sediments and deformation is provided by a LA-ICP-MS zircon U-Pb age of 3219. ±. 9. Ma obtained from an undeformed felsic dike which crosscuts folded Moodies strata. This age overlaps with a precise CA-ID-TIMS U-Pb zircon age of 3216.0. ±. 0.3. Ma obtained from a tuff horizon of the upper Moodies Group. Overall, the new age data collectively imply that the up to 3.7. km-thick, sandstone-dominated Moodies Group was deposited and deformed within <1-14. Ma, and that Moodies strata thus hold the potential to offer a temporal resolution comparable to active- and passive-margin Quaternary strata (~0.1-1. mm/a). © 2013 Elsevier B.V. Article 2013 English 03019268 10.1016/j.precamres.2013.03.021 Precambrian Research 231 236 – 262 Barberton Greenstone Belt; Ficus (angiosperm); alluvial deposit; Archean; deformation; deposition; dike; felsic rock; fluvial deposit; geochronology; sandstone; sedimentary rock; siliciclastic deposit; subsidence; tuff; zircon https://www.scopus.com/inward/record.uri?eid=2-s2.0-84877035734&doi=10.1016%2fj.precamres.2013.03.021&partnerID=40&md5=9382a2d81ef583f245319f7eb4641ad5 Cited by: 71 Christoph Heubeck Jonathan Engelhardt Gary R. Byerly Armin Zeh Bryan Sell Tim Luber Donald R. Lowe article Damaschke2013267 A detailed tephrostratigraphic record, which dates back to Marine Isotope Stage (MIS) 5b (ca. 91 kyr), has been established from a 17.76 m long core (Co1215) from Lake Prespa (Macedonia, Albania and Greece). A total of eleven tephra and cryptotephra layers (PT0915-1 to PT0915-11) were identified, using XRF scanning, magnetic susceptibility measurements, and macro- and microscopic inspection of the sediments. The major element composition of glass shards and/or micro-pumice fragments indicates that the tephras and cryptotephras originate from the explosive volcanism of Italy. Eight tephra and cryptotephra layers were correlated with specific volcanic eruptions: the AD 512 eruption of Somma-Vesuvius (1438 cal yr BP), the Mercato eruption of Somma-Vesuvius (8890 ± 90 cal yr BP), the Tufi Biancastri/LN1-LN2 eruption of the Campi Flegrei (14 749 ± 523 cal yr BP and 15 551 ± 621 cal yr BP), the SMP1-e/Y-3 eruption of the Campi Flegrei (30 000-31 000 cal yr BP), the Campanian Ignimbrite/Y-5 eruption of the Campi Flegrei (39 280 ± 110 cal yr BP), the SMP1-a event of Ischia Island (around 44 000 cal yr BP) and the Green Tuff/Y-6 eruption of Pantelleria Island (around 45 000 cal yr BP). One tephra could be attributed to the volcanic activity of Mount Etna, but probably represents an unknown eruption at ca. 60 000 cal yr BP. Cryptotephras PT0915-6 and PT0915-10 remain unclassified so far, but according to the presented age-depth model these would have been deposited around 35 000 and 48 500 cal yr BP, respectively. Some of the tephras and cryptotephras are recognised for the first time in the Balkan region. The tephrostratigraphic work provides important information about ash dispersal and explosion patterns of source volcanoes and can be used to correlate and date geographically distant paleoenvironmental and archaeological archives in the central Mediterranean region. Moreover, the tephrostratigraphic work in combination with radiocarbon and electron spin resonance (ESR) dating is a precondition for paleoclimatic reconstructions inferred from the sediment succession Co1215. © 2013 Author(s). Article 2013 English 18149332 10.5194/cp-9-267-2013 Climate of the Past 9 267 – 287 1 Balkans; Campania [Italy]; Ischia; Italy; Lake Mikri Prespa; Napoli [Campania]; age; archaeology; biostratigraphy; chemical composition; fragmentation; numerical model; paleoenvironment; sediment core; tephrochronology https://www.scopus.com/inward/record.uri?eid=2-s2.0-84874339683&doi=10.5194%2fcp-9-267-2013&partnerID=40&md5=1a58c600666886e6f2744f6698b7fb2d Cited by: 37; All Open Access, Gold Open Access, Green Open Access M. Damaschke R. Sulpizio G. Zanchetta B. Wagner A. Böhm N. Nowaczyk J. Rethemeyer A. Hilgers article Liu2013153 The isotopic compositions of total organic carbon (TOC) in lakes have been widely used to interpret paleoclimatic changes and the depositional environments of lake sediments. However, the main factors that affect the carbon isotopes of TOC (source of organic material, water condition and others) may vary in different lake sediment records, which have limited the applicability of organic carbon isotopes in explaining biogeochemical and environmental changes in lakes. In this study, the organic carbon isotopic compositions of aquatic plants and surface sediments from Lake Qinghai and the living terrestrial plants and surface soils around the lake were systematically investigated to identify the sources of TOC in the sediments and the significance of the organic carbon isotopes of sedimentary TOC. We found that the aquatic plants in the deep water areas (>10m) were primarily dominated by Cladophora, but submerged plants (Potamogeton and Ruppia L.) are the dominant species in shallow water (<10m). The Cladophora have negative δ13Corg values (-33.6‰ to -28.6‰) that are caused by C3-like photosynthesis, but the submerged plants have enriched δ13Corg values (-17.8‰ to -15.4‰) that are caused by C4-like photosynthesis. In addition, the δ13Corg values of Cladophora become more negative with increasing water depth because of the slow photosynthetic rate caused by the weak light intensity at depth. The isotopic data indicate that the carbon isotopes of organic material in the surface sediments are primarily controlled by the types of aquatic plant and that the δ13Corg values of TOC can be used to indicate the variation of the water depth (lake level). The organic carbon isotopic data from the 1F core showed that the water was shallow (<10m) because of intense evaporation related to high temperatures even though precipitation sharply increased in the warm period during the early-mid Holocene. The lake level reached its maximum level at 3ka. © 2013 Elsevier B.V. Article 2013 English 00092541 10.1016/j.chemgeo.2013.04.009 Chemical Geology 347 153 – 160 China; Qinghai; Qinghai Lake; Qinghai-Xizang Plateau; Cladophora; Potamogeton; Ruppia; Carbon; Isotopes; Organic carbon; Photosynthesis; Sedimentology; Slow light; Surficial sediments; Carbon isotopic composition; Depositional environment; Isotopic composition; Lake levels; Lake Qinghai; Lake-sediment records; Qinghai Tibet plateau; Total Organic Carbon; carbon isotope; environmental change; green alga; isotopic composition; lacustrine deposit; lake level; precipitation (chemistry); sediment chemistry; total organic carbon; water depth; Lakes https://www.scopus.com/inward/record.uri?eid=2-s2.0-84877333028&doi=10.1016%2fj.chemgeo.2013.04.009&partnerID=40&md5=68fa11bfb726dd364555465418cc4527 Cited by: 104 Weiguo Liu Xiangzhong Li ZhiSheng An Liming Xu article Wastegård201381 A total of 18 tephra samples have been analysed from the composite sediment sequence from Site 2 of the Laguna Potrok Aike ICDP expedition 5022 from southern Patagonia, Argentina, which extends back to ca 51kacalBP. Analyses of the volcanic glass show that all layers but one are rhyolitic in composition, with SiO2 contents ranging between ca 74.5 and 78wt% and suggest an origin in the Austral Andean Volcanic Zone (AVZ; 49-55°S). Nonetheless, two main data clusters occur, one group with K2O contents between ca 1.5 and 2.0wt%, indicating an origin in the Mt. Burney volcanic area, and one group with K2O contents between ca 2.7 and 3.9wt%, tentatively correlated with Viedma/Lautaro and the Aguilera volcanoes in the northern part of the AVZ. The early Holocene Tephra, MB1 and the late Pleistocene Reclus R1 tephra occur in the upper part of the sequence. Periods with significant tephra deposition occurred between ca 51-44kacalBP, and ca 31-25kacalBP, with a decrease in tephra layer frequency between these two periods. © 2012 Elsevier Ltd. Article 2013 10.1016/j.quascirev.2012.10.019 Quaternary Science Reviews 71 81 – 90 Argentina; Laguna Potrok Aike; Santa Cruz [Argentina]; Geology; Natural sciences; Chronology; ICDP-project PASADO; Mt. Burney; Pleistocene; Tephra; Volcanic; community composition; oxide; Quaternary; sediment analysis; tephrochronology; volcanic eruption; Volcanoes https://www.scopus.com/inward/record.uri?eid=2-s2.0-84878926863&doi=10.1016%2fj.quascirev.2012.10.019&partnerID=40&md5=9815d7f066a70570c70de3fdeaaf8105 Cited by: 38 S. Wastegård D. Veres P. Kliem A. Hahn C. Ohlendorf B. Zolitschka article salminen2013tracking 2013 Precambrian Research 228 Elsevier 177--193 Paula E Salminen Juha A Karhu Victor A Melezhik article Salminen2013177 Article 2013 10.1016/j.precamres.2013.01.005 Precambrian Research 228 177 – 193 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84873932514&doi=10.1016%2fj.precamres.2013.01.005&partnerID=40&md5=91b80fab323a97fb07dab21bd720d912 Cited by: 5 Paula E. Salminen Juha A. Karhu Victor A. Melezhik article Leng2013123 Here we present stable isotope and geochemical data from Lake Prespa (Macedonia/Albania border) over the Last Glacial cycle (Marine Isotope Stages 5e1) and discuss past lake hydrology and climate (TIC, oxygen and carbon isotopes), as well as responses to climate of terrestrial and aquatic vegetation (TOC, Rock Eval pyrolysis, carbon isotopes, pollen). The Lake Prespa sediments broadly fall into 5 zones based on their sedimentology, geochemistry, palynology and the existing chronology. The Glacial sediments suggest low supply of carbon to the lake, but high summer productivity; intermittent siderite layers suggest that although the lake was likely to have mixed regularly leading to enhanced oxidation of organic matter, there must have been within sediment reducing conditions and methanogenesis. MIS 5 and 1 sediments suggest much more productivity, higher rates of organic material preservation possibly due to more limited mixing with longer periods of oxygen-depleted bottom waters. We also calculated lakewater d18O from siderite (authigenic/Glacial) and calcite (endogenic/Holocene) and show much lower lakewater d18O values in the Glacial when compared to the Holocene, suggesting the lake was less evaporative in the Glacial, probably as a consequence of cooler summers and longer winter ice cover. In the Holocene the oxygen isotope data suggests general humidity, with just 2 marked arid phases, features observed in other Eastern and Central Mediterranean lakes. © 2012 Elsevier Ltd. Article 2013 English 02773791 10.1016/j.quascirev.2012.07.015 Quaternary Science Reviews 66 Elsevier Ltd 123 – 136 Albania; Lake Mikri Prespa; Macedonia [Southern Europe]; Geochemistry; Glacial geology; Iron ores; Isotopes; Oxygen; Productivity; Pyrolysis; Sediments; Central Mediterranean; Hydrological variability; Late quaternary; Marine isotope stages; Mediterranean; Reducing conditions; Rock-Eval pyrolysis; Stable isotopes; bottom water; climate effect; hydrological change; lacustrine deposit; lake water; Last Glacial; marine isotope stage; Mediterranean environment; methanogenesis; oxidation; oxygen isotope; paleoclimate; paleoecology; paleohydrology; palynology; preservation; pyrolysis; stable isotope; Lakes https://www.scopus.com/inward/record.uri?eid=2-s2.0-84879561600&doi=10.1016%2fj.quascirev.2012.07.015&partnerID=40&md5=d7f7c1af236f88a59f108915361a019b Cited by: 60; All Open Access, Green Open Access Melanie J. Leng Bernd Wagner Anne Boehm Konstantinos Panagiotopoulos Christopher H. Vane Andrea Snelling Cheryl Haidon Ewan Woodley Hendrik Vogel Gianni Zanchetta Ilaria Baneschi article cp-9-1211-2013 Preliminary analyses of Lake El'gygytgyn sediment indicate a wide range of ecosystem responses to warmer than present climates. While palynological work describing all interglacial vegetation is ongoing, sufficient data exist to compare recent warm events (the postglacial thermal maximum, PGTM, and marine isotope stage, MIS5) with "super" interglaciations (MIS11, MIS31). Palynological assemblages associated with these climatic optima suggest two types of vegetation responses: one dominated by deciduous taxa (PGTM, MIS5) and the second by evergreen conifers (MIS11, MIS31). MIS11 forests show a similarity to modern Picea-Larix-Betula-Alnus forests of Siberia. While dark coniferous forest also characterizes MIS31, the pollen taxa show an affinity to the boreal forest of the lower Amur valley (southern Russian Far East). Despite vegetation differences during these thermal maxima, all glacial-interglacial transitions are alike, being dominated by deciduous woody taxa. Initially Betula shrub tundra established and was replaced by tundra with tree-sized shrubs (PGTM), Betula woodland (MIS5), or Betula-Larix (MIS11, MIS31) forest. The consistent occurrence of deciduous forest and/or high shrub tundra before the incidence of maximum warmth underscores the importance of this biome for modeling efforts. The El'gygytgyn data also suggest a possible elimination or massive reduction of Arctic plant communities under extreme warm-earth scenarios. © Author(s) 2013. 2013 English 18149324 10.5194/cp-9-1211-2013 Climate of the Past 9 1211-1219 Northeast Interdisciplinary Scientific Research Institute, Far East Branch, Russian Academy of Sciences, 16 Portovaya Street, Magadan 685000, Russian Federation; Earth and Space Sciences and Quaternary Research Center, University of Washington, Seattle, WA 98195-1310, United States 3 arctic environment; community response; coniferous tree; deciduous tree; dominance; evergreen tree; glacial-interglacial cycle; interglacial; lacustrine deposit; marine isotope stage; paleoecology; palynology; plant community; shrub; tundra; vegetation structure; warming, Arctic; Chukchi; Elgygytgyn Lake; Russian Federation https://cp.copernicus.org/articles/9/1211/2013/ cited By 25 A. V. Lozhkin P. M. Anderson article Dahm2013957 Crustal earthquake swarms are an expression of intensive cracking and rock damaging over periods of days, weeks or month in a small source region in the crust. They are caused by longer lasting stress changes in the source region. Often, the localized stressing of the crust is associated with fluid or gas migration, possibly in combination with pre-existing zones of weaknesses. However, verifying and quantifying localized fluid movement at depth remains difficult since the area affected is small and geophysical prospecting methods often cannot reach the required resolution. We apply a simple and robust method to estimate the velocity ratio between compressional (P) and shear (S) waves (vP/vS-ratio) in the source region of an earthquake swarm. The vP/vP-ratio may be unusual small if the swarm is related to gas in a porous or fractured rock. The method uses arrival time difference between P and S waves observed at surface seismic stations, and the associated double differences between pairs of earthquakes. An advantage is that earthquake locations are not required and the method seems lesser dependent on unknown velocity variations in the crust outside the source region. It is, thus, suited for monitoring purposes. Applications comprise three natural, mid-crustal (8-10 km) earthquake swarms between 1997 and 2008 from the NW-Bohemia swarm region. We resolve a strong temporal decrease of vP/vP before and during the main activity of the swarm, and a recovery of vP/vP to background levels at the end of the swarms. The anomalies are interpreted in terms of the Biot-Gassman equations, assuming the presence of oversaturated fluids degassing during the beginning phase of the swarm activity. © The Authors 2013. Published by Oxford University Press on behalf of The Royal Astronomical Society. Article 2013 English 1365246X 10.1093/gji/ggt410 Geophysical Journal International 196 957 – 970 2 Bohemia; Czech Republic; Geophysical prospecting; Shear flow; Tomography; Transport properties; Velocity; Crustal earthquakes; Double differences; Earthquake location; Earthquake source observations; Earthquake swarms; Monitoring purpose; Velocity variations; Volcano seismology; anomaly; arrival time; earthquake swarm; P-wave; S-wave; seismic source; seismic tomography; seismic velocity; seismology; Earthquakes https://www.scopus.com/inward/record.uri?eid=2-s2.0-84891559309&doi=10.1093%2fgji%2fggt410&partnerID=40&md5=eb58ca41b921ba4b961994e5b5174b12 Cited by: 23; All Open Access, Green Open Access, Hybrid Gold Open Access Torsten Dahm Tomáš Fischer article Fanara2013149 Water diffusivity was investigated in phonolitic and trachytic melts containing up to 6wt.% of dissolved water at temperatures between 1373K and 1673K for running time of 108 to 1186s using the diffusion couple technique. The experiments were performed in an internally heated gas pressure vessel (IHPV) at pressures of 0.2 or 0.3GPa and in a piston cylinder apparatus (PCA) at pressures between 0.5 and 2.5GPa. A newly developed rapid heating and rapid quench device was used for short term experiments in the IHPV. Concentration profiles of hydrous species (OH groups and H2O molecules) and total water (bulk water concentration as sum of OH and H2O molecules) were measured along the cylindrical axis of the diffusion sample using IR micro-spectroscopy. The IR spectroscopic technique was calibrated using a set of samples with bulk water contents measured by Karl-Fischer titration. Electron microprobe traverses show no significant change in relative proportions of anhydrous components along H2O profiles, indicating that our data can be treated as effective binary diffusion between H2O and the rest of the silicate melt.Bulk water diffusivity was derived from profiles of total water using a modified Boltzmann-Matano method as well as using fittings assuming a functional relationship between the total water diffusivity (DH2Ot) and the total water concentration (CH2Ot). The fitting of the profiles indicates that for phonolitic melt the water diffusivity is roughly proportional to water content. The following formulation was derived for the prediction of total water diffusivity (m2/s) as a function of T (K) in the T-range of 1373 to 1673K and CH2Ot:logDH2Ot=-7.11-2.07logCH2Ot-4827-4620logCH2OtT.The experimental data are reproduced by this relationship with a standard deviation of 0.07. log units. Water diffusivity in trachytic melts is similar at the same conditions. A pressure effect on water diffusivity could not be resolved in the range 0.2 to 2.5. GPa for phonolitic or trachytic melts. © 2012 Elsevier B.V. Article 2013 English 00092541 10.1016/j.chemgeo.2012.09.030 Chemical Geology 346 149 – 161 Experiments; Infrared spectroscopy; Molecules; Pressure effects; Silicates; Water content; Boltzmann-Matano method; Diffusion couple technique; Functional relationship; Phonolite; Piston-cylinder apparatus; Spectroscopic technique; Trachyte; Water diffusion; concentration (composition); diffusivity; infrared spectroscopy; phonolite; potassium; silicate melt; trachyte; water content; Diffusion in liquids https://www.scopus.com/inward/record.uri?eid=2-s2.0-84876979910&doi=10.1016%2fj.chemgeo.2012.09.030&partnerID=40&md5=8f23882e8aa1952cce384575a25addda Cited by: 25 Sara Fanara Harald Behrens Youxue Zhang article Quinteros201331 The classic example of the not-well-understood rapid change of tectonic plate motion is the increase and then decrease of the convergence rate between the Nazca and South America plates during the past 25-20 m.y. that coincided with the growth of the Andes Mountains. Currently, the decrease in convergence rate is explained either by the increasing load of the Andes or by the appearance of fl at slab segments beneath South America. Here, we present an alternative view based on a thermomechanical self-consistent (gravity driven) model of Nazca plate subduction. We explain the changes in the convergence rate as a natural consequence of the Nazca plate penetration into the transition zone and lower mantle after long-term oblique subduction of the Farallon plate. The model is consistent with seismic tomographic images of the Nazca plate beneath South America. Our model also shows that the presence of the Andes does not signifi cantly affect the convergence rate between the Nazca and South America plates. © 2012 Geological Society of America. 2013 English 00917613 10.1130/G33497.1 Geology 41 31-34 Deutsches GeoForschungsZentrum GFZ, Telegrafenberg, 14473 Potsdam, Germany; Department of Computer Sciences, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires C1428EGA, Argentina; Institute of Physics of the Earth, Russian Academy of Sciences, Moscow 123995, Russian Federation 1 Convergence rates; Lower mantle; Natural consequences; Nazca plate; Neo genes; Oblique subduction; Seismic tomographic images; South America; Tectonic plates; Thermo-mechanical; Transition zones; View-based, Geology, Tomography, Nazca plate; Neogene; plate motion; seismic tomography; subduction zone; transition zone, Andes https://www.scopus.com/inward/record.uri?eid=2-s2.0-84872140078&doi=10.1130%2fG33497.1&partnerID=40&md5=34c01255a4d1f048997d4f88d1f35a4e cited By 53 J. Quinteros S.V. Sobolev article Goderis20131296 The geochemical nature of the impactites from International Continental Scientific Drilling Project-El'gygytgyn lake drill core 1C is compared with that of impact melt rock fragments collected near the western rim of the structure and literature data. Concentrations of major and trace elements, with special focus on siderophile metals Cr, Co, Ni, and the platinum group elements, and isotope ratios of osmium (Os), were determined to test the hypothesis of an ureilite impactor at El'gygytgyn. Least squares mixing calculations suggest that the upper volcanic succession of rhyolites, dacites, and andesites were the main contributors to the polymict impact breccias. Additions of 2-13.5 vol% of basaltic inclusions recovered from drill core intervals between 391.6 and 423.0 mblf can almost entirely account for the compositional differences observed for the bottom of a reworked fallout deposit at 318.9 mblf, a polymict impact breccia at 471.4 mblf, and three impact melt rock fragments. However, the measured Os isotope ratios and slightly elevated PGE content (up to 0.262 ng g-1 Ir) of certain impactite samples, for which the CI-normalized logarithmic PGE signature displays a relatively flat (i.e., chondritic) pattern, can only be explained by the incorporation of a small meteoritic contribution. This component is also required to explain the exceptionally high siderophile element contents and corresponding Ni/Cr, Ni/Co, and Cr/Co ratios of impact glass spherules and spherule fragments that were recovered from the reworked fallout deposits and from terrace outcrops of the Enmyvaam River approximately 10 km southeast of the crater center. Mixing calculations support the presence of approximately 0.05 wt% and 0.50-18 wt% of ordinary chondrite (possibly type-LL) in several impactites and in the glassy spherules, respectively. The heterogeneous distribution of the meteoritic component provides clues for emplacement mechanisms of the various impactite units. © The Meteoritical Society, 2013. 2013 10.1111/maps.12047 Meteoritics and Planetary Science 48 1296-1324 Department of Geology, Earth System Science, Vrije Universiteit Brussel, Pleinlaan 2, Brussels, BE-1050, Belgium; Department of Analytical Chemistry, Ghent University, Krijgslaan 281-S12, Ghent, BE-9000, Belgium; Department of Earth and Planetary Sciences, Washington University St. Louis, Campus Box 1169, 1 Brookings Dr., St. Louis, MO, 63130-4899, United States; Lunar and Planetary Institute, 3600 Bay Area Blvd., Houston, TX, 77058, United States; Department of Geology and Geophysics, University of Hawaii at Manoa, Honolulu, HI, United States; Department of Geology and Soil Sciences, Ghent University, Krijgslaan 281-S8, Ghent, BE-9000, Belgium; School of Agricultural, Earth and Environmental Sciences, University of KwaZulu-Natal, Durban, South Africa; Institut für Planetologie, Westfälische Wilhelms-Universität Münster, Wilhelm-Klemm-Str. 10, Münster, D-48149, Germany 7 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84880159710&doi=10.1111%2fmaps.12047&partnerID=40&md5=df03802e99801688dea1e0c663fc3ae8 cited By 15 S. Goderis A. Wittmann J. Zaiss M. Elburg G. Ravizza F. Vanhaecke A. Deutsch P. Claeys article Mallika2013189 It is generally found that the b values associated with reservoir-triggered seismicity (RTS) are higher than the regional b values in the frequency magnitude relation of earthquakes. In the present study, temporal and spatial variation of b value is investigated using a catalog of 3,000 earthquakes from August 2005 through December 2010 for the Koyna-Warna region in Western India, which is a classical site of RTS globally. It is an isolated (30 × 20 km2) zone of seismicity where earthquakes of up to M ~5 are found to occur during phases of loading and unloading of the Koyna and Warna reservoirs situated 25 km apart. For the Warna region, it is found that low b values of 0. 6-0. 9 are associated with earthquakes of M ~4 during the loading phase. The percentage correlation of the occurrence of an M ≥ 4 earthquake with a low b value outside the 1σ or 2σ level is as high as 78 %. A drastic drop in the b value of about 50 % being reported for an RTS site may be an important precursory parameter for short-term earthquake forecast in the future. © 2012 Springer Science+Business Media B.V. 2013 English 13834649 10.1007/s10950-012-9318-3 Journal of Seismology 17 Kluwer Academic Publishers 189-195 National Geophysical Research Institute (CSIR-NGRI), Uppal Road, Hyderabad, India 1 earthquake event; earthquake magnitude; earthquake precursor; earthquake prediction; earthquake trigger; loading; reservoir-induced seismicity; seismic isolation; temporal variation; unloading, India; Koyna; Maharashtra; Warna https://www.scopus.com/inward/record.uri?eid=2-s2.0-84871079528&doi=10.1007%2fs10950-012-9318-3&partnerID=40&md5=d27664a84120253a7d6463cc8698fc95 cited By 21 K. Mallika H. Gupta D. Shashidhar N.P. Rao A. Yadav S. Rohilla H.V.S. Satyanarayana D. Srinagesh article Artemieva2013590 We present the results of numerical modeling of the formation of the Ries crater utilizing the two hydrocodes SOVA and iSALE. These standard models allow us to reproduce crater shape, size, and morphology, and composition and extension of the continuous ejecta blanket. Some of these results cannot, however, be readily reconciled with observations: the impact plume above the crater consists mainly of molten and vaporized sedimentary rocks, containing very little material in comparison with the ejecta curtain; at the end of the modification stage, the crater floor is covered by a thick layer of impact melt with a total volume of 6-11 km3; the thickness of true fallback material from the plume inside the crater does not exceed a couple of meters; ejecta from all stratigraphic units of the target are transported ballistically; no separation of sedimentary and crystalline rocks-as observed between suevites and Bunte Breccia at Ries-is noted. We also present numerical results quantifying the existing geological hypotheses of Ries ejecta emplacement from an impact plume, by melt flow, or by a pyroclastic density current. The results show that none of these mechanisms is consistent with physical constraints and/or observations. Finally, we suggest a new hypothesis of suevite formation and emplacement by postimpact interaction of hot impact melt with water or volatile-rich sedimentary rocks. © The Meteoritical Society, 2013. 2013 10.1111/maps.12085 Meteoritics and Planetary Science 48 590-627 Planetary Science Institute, 1700 E. Fort Lowell Rd., Tucson, AZ, 85719, United States; Museum für Naturkunde, Leibniz Institute for Research on Evolution and Biodiversity, Invalidenstrasse 43, Berlin, 10115, Germany; Institute for the Dynamics of Geospheres, Russian Academy of Sciences, Moscow, 119334, Russian Federation; Humboldt Universität zu Berlin, Unter den Linden 6, Berlin, 10099, Germany 4 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84876416674&doi=10.1111%2fmaps.12085&partnerID=40&md5=260528458ab7ea8e4f841ab4e2e60513 cited By 77 N.A. Artemieva K. Wünnemann F. Krien W.U. Reimold D. Stöffler article Mang201364 Shock experiments with pressures ranging from 3 to 30 GPa have been conducted on a mixed assemblage of hexagonal and monoclinic pyrrhotite. All samples were studied with respect to their particular shock-induced microstructures and magnetic properties at high and low temperatures. Up to 8 GPa, microstructures in shocked pyrrhotite are characterized by mechanical deformation producing a damage of the crystal structure. At pressures of 20 GPa and upward, amorphization and mechanical twinning are the dominant structural features induced by shock. Within the lower-pressure range coercivity, saturation isothermal remanent magnetization and coercivity of remanence increase with shock pressures, in agreement with more single-domain (SD)-like behavior. Simultaneously, the λ-peak of hexagonal pyrrhotite decreases and the 34 K transition of monoclinic pyrrhotite broadens and is depressed. Magnetic hardening is triggered by grain-size reduction, but also by the formation of SD within discrete multidomain grains. Planar deformation features subdivide such multidomain grains into lath-shaped domains with average sizes lying in the SD range. The planar deformation features disappear at 20 GPa and irregular, nanometer-sized "amorphous domains" occur instead. Pressure release from 30 GPa finally triggers partial melting of pyrrhotite. The sharp interfaces between molten and crystalline pyrrhotite document a rapid change of thermal conditions. Within molten pyrrhotite, quenched iron crystals occur. The presence of native iron strongly influences the magnetic properties, depending on the particular amount in the studied sample and likely affects the magnetic properties of impact lithologies on Earth and extraterrestrial material. ©2013. American Geophysical Union. All Rights Reserved. 2013 English 15252027 10.1029/2012GC004242 Geochemistry, Geophysics, Geosystems 14 Blackwell Publishing Ltd 64-85 Institut für Angewandte Geowissenschaften, Karlsruher Institut für Technologie, Adenauerring 20, Geb. 50.40, D-76131 Karlsruhe, Germany; Museum für Naturkunde, Leibniz-Institut, Humboldt Universität zu Berlin, Berlin, Germany; Laboratorium für Elektronenmikroskopie, Karlsruher Institut für Technologie, Karlsruhe, Germany 1 Coercive force; Experiments; Magnetic properties; Microstructure, Coercivity of remanence; Extraterrestrial material; Grain-size reduction; Mechanical deformation; Mechanical twinning; pyrrhotite; Saturation isothermal remanent magnetizations; shock, Iron ores, crystal structure; deformation; experimental study; grain size; lithology; magnetic property; microstructure; pyrrhotite; remanent magnetization; temperature effect https://www.scopus.com/inward/record.uri?eid=2-s2.0-84879807327&doi=10.1029%2f2012GC004242&partnerID=40&md5=4ee9274ee3c5d51772d1bf852c98572f cited By 21 C. Mang A. Kontny J. Fritz R. Schneider article cp-9-467-2013 2013 10.5194/cp-9-467-2013 Climate of the Past 9 467-479 1 https://cp.copernicus.org/articles/9/467/2013/ K. J. Murdock K. Wilkie L. L. Brown article Li201371 The south borehole (SK-1s) of the China Cretaceous Continental Scientific Drilling project (Songke 1) penetrated the Late Cretaceous lacustrine sediments in the central depression of the Songliao Basin, Northeast China, in order to reveal the terrestrial records of the Cretaceous climate changes. High-resolution rock magnetic records were obtained on the Qingshankou Formation (K2qn) of SK-1s. The results indicate that detrital magnetite is the main remanence-carrier of the K2qn Formation; while both magnetite and paramagnetic minerals, including clay minerals and pyrite, dominantly contribute to magnetic susceptibility. Although reductive diagenesis may have more or less effect on the magnetic signals of the K2qn Formation, they recorded ancient lake-level changes well, resulting both from the tectonic development of the basin and from the Milankovitch astronomical paleoclimatic changes. The first-order vertical trends of the rock magnetic records were controlled by the shallowing-upwards of the lake-level, caused by the tectonic uplift of the basin. The short-term variations of the rock magnetic records were controlled by the lake-level periodical drift, caused by the fluctuations of the rainfall of the catchment area of the basin, which were controlled by astronomical orbital forcing. In addition, the magnetic records also distinguished two most anoxic periods during the lacustrine anoxic event 1 (LAE1): the sections of 1758-1761m and 1769-1771.5m, which may suggest the two most active periods of surface productivity of the lake. © 2013 Elsevier B.V. 2013 English 00310182 10.1016/j.palaeo.2013.02.007 Palaeogeography, Palaeoclimatology, Palaeoecology 385 71-82 State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing 100083, China borehole; climate variation; Cretaceous; detrital deposit; diagenesis; lacustrine deposit; lake level; magnetic field; magnetic mineral; magnetic susceptibility; magnetite; Milankovitch cycle; orbital forcing; paleoclimate; pyrite; remanent magnetization; uplift, China; Songliao Basin https://www.scopus.com/inward/record.uri?eid=2-s2.0-84879886584&doi=10.1016%2fj.palaeo.2013.02.007&partnerID=40&md5=3020611beb06d43e892d2f9655eb18bf cited By 8 H. Li S. Zhang H. Wu K. Zhao T. Yang L. Zhao article Liu20132229 Rock varnish from 14.6 to 13.2 ka recessional shorelines of late glacial Lake Lisan and fan delta surfaces between 280 and 365 m bmsl (meters below mean sea level) along the western margins of the Dead Sea contains replicable layering patterns, characterized by a low Mn and Ba orange/yellow surface layer and a high Mn and Ba dark basal layer. The deposition of the dark basal layers immediately after the lake recession represents a wet period coinciding with the Younger Dryas (YD) cooling (12.9-11.6 ka), manifesting the influence of midlatitude westerly winds in the eastern Mediterranean-central Levant (EM-CL). In contrast, varnish from the distal base of fan deltas contains only orange/yellow surface layers, diagnostic of the Holocene relatively dry climate. The absence of the dark basal layers in the varnish further indicates a YD high stand at ∼365 m bmsl and a lake level rise of at least 100 m from its Bølling-Ållerød lowstand. This rise stands in contrast to the abrupt drop of the lake level during the Heinrich (H1) cold event, illustrating the opposite response of the EM-CL climate to changes in the North Atlantic climate. The YD wet event most likely reflects a southward shift of the Atlantic meridional overturning circulation-modulated midlatitude westerly wind belt in the EM-CL region. © 2013 American Geophysical Union. All Rights Reserved. 2013 English 00948276 10.1002/grl.50492 Geophysical Research Letters 40 2229-2235 Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY 10964, United States; Geological Survey of Israel, Jerusalem, Israel 10 Dead sea; Dead sea basins; Mean sea level; North Atlantic; Rock varnishes; Surface layers; wet event; Younger Dryas, Lakes; Manganese; Sea level; Varnish, Climate change, belt; depositional environment; glacial environment; Holocene; meridional circulation; shoreline; surface layer, Dead Sea https://www.scopus.com/inward/record.uri?eid=2-s2.0-84879951769&doi=10.1002%2fgrl.50492&partnerID=40&md5=a1d7c23d93efd09294ebd83a79aa4570 cited By 22 T. Liu W.S. Broecker M. Stein article Babaie201383 Scientific drilling near Parkfield, California has established the San Andreas Fault Observatory at Depth (SAFOD), which provides the solid earth community with short range geophysical and fault zone material data. The BM2KB ontology was developed in order to formalize the knowledge about brittle microstructures in the fault rocks sampled from the SAFOD cores. A knowledge base, instantiated from this domain ontology, stores and presents the observed microstructural and analytical data with respect to implications for brittle deformation and mechanics of faulting. These data can be searched on the knowledge base's Web interface by selecting a set of terms (classes, properties) from different drop-down lists that are dynamically populated from the ontology. In addition to this general search, a query can also be conducted to view data contributed by a specific investigator. A search by sample is done using the EarthScope SAFOD Core Viewer that allows a user to locate samples on high resolution images of core sections belonging to different runs and holes.The class hierarchy of the BM2KB ontology was initially designed using the Unified Modeling Language (UML), which was used as a visual guide to develop the ontology in OWL applying the Protégé ontology editor. Various Semantic Web technologies such as the RDF, RDFS, and OWL ontology languages, SPARQL query language, and Pellet reasoning engine, were used to develop the ontology. An interactive Web application interface was developed through Jena, a java based framework, with AJAX technology, jsp pages, and java servlets, and deployed via an Apache tomcat server. The interface allows the registered user to submit data related to their research on a sample of the SAFOD core. The submitted data, after initial review by the knowledge base administrator, are added to the extensible knowledge base and become available in subsequent queries to all types of users. The interface facilitates inference capabilities in the ontology, supports SPARQL queries, allows for modifications based on successive discoveries, and provides an accessible knowledge base on the Web. © 2013 Elsevier Ltd. 2013 English 00983004 10.1016/j.cageo.2013.03.004 Computers and Geosciences 56 83-91 Department of Geosciences, Georgia State University, P.O. Box 4105, Atlanta, GA 30302-4105, United States; Department of Geography and Geosciences, University of Louisville, Louisville, KY 40292, United States Apache Tomcat server; High resolution image; Interactive web applications; OWL; RDF; SAFOD core; San Andreas fault; Semantic Web technology, Knowledge based systems; Microstructure; Query languages; Strike-slip faults; Unified Modeling Language, Core samples, brittle deformation; brittle medium; drilling; faulting; knowledge; microstructure; San Andreas Fault https://www.scopus.com/inward/record.uri?eid=2-s2.0-84876336988&doi=10.1016%2fj.cageo.2013.03.004&partnerID=40&md5=e060233aaa72aa45312d8bdca5a6984d cited By 2 H.A. Babaie M. Broda Cindi J. Hadizadeh A. Kumar article kelemen2013scientific 2013 Scientific Drilling 15 Copernicus GmbH 64--71 Peter Kelemen Ali Al Rajhi Marguerite Godard Benoit Ildefonse Jürgen Köpke Chris MacLeod Craig Manning Katsu Michibayashi Sobhi Nasir Everett Shock others article McCarthy20131457 Integrated Ocean Drilling Program Expedition 313 recovered Miocene sequences at Holes M0027A and M0029A on the New Jersey shallow shelf that contain a characteristic acid-resistant organic component. The palynofacies within each sequence refl ects variations in terrigenous versus authigenic fl ux through the Miocene that are associated with sea-level change. Very high ratios of terrigenous versus marine palynomorphs and of oxidation-resistant versus susceptible dinocysts are associated with seismic sequence boundaries, consistent with their interpretation as sequence-bounding unconformities generated at times of low sea level. Comparison of palynological distance from shoreline estimates with paleodepth estimates derived from foraminiferal data allows relative sea level to be reconstructed at both sites. Ages assigned using dinocyst biostratigraphy are consistent with other chronostratigraphic indicators allowing sequence boundaries to be correlated with Miocene oxygen isotope (Mi) events. Paleoclimatic evidence from the pollen record supports the global climate changes seen in the oxygen isotope data. Although chronological control is relatively crude, Milankovitch-scale periodicity is suggested for parasequences visible in thick sequences deposited in relatively deep water where substantial accommodation existed, such as during the early Langhian at Site 29 (Middle Miocene Climatic Optimum). Palyno logical analysis thus supports the long-held hypothesis that glacioeustasy is a dominant process controlling the architecture of continental margins. 2013 English 1553040X 10.1130/GES00853.1 Geosphere 9 1457-1487 Department of Earth Sciences, Brock University, Catharines, ONT L2S 3A1, Canada; Department of Earth and Environmental Sciences, Rensselaer Polytechnic Institute, Troy, NY 12180, United States; Institut für Geologie, Universität Hamburg, Bundesstrasse 55, 20146 Hamburg, Germany; Department of Earth and Planetary Sciences, Rutgers University, Piscataway, NJ 08854, United States; Camborne School of Mines, College of Engineering, Mathematics and Physical Sciences, University of Exeter, Penryn Campus, Penryn, Cornwall TR10 9EZ, United Kingdom; Nordic Centre for Earth Evolution (NordCEE), Department of Geosciences and Natural Resource Management, Øster Voldgade 10, DK-1350, Copenhagen K, Denmark 6 Continental margin; Global climate changes; Integrated ocean drilling programs; Organic components; Oxidation resistant; Relative sea level; Sea-level control; Sequence-bounding unconformities, Isotopes; Oxygen; Submarine geology, Sea level, biostratigraphy; chronostratigraphy; continental shelf; glacioeustacy; Miocene; Ocean Drilling Program; palynology; sea level change; sequence boundary; sequence stratigraphy, Atlantic Ocean; New Jersey Margin; New Jersey Shelf https://www.scopus.com/inward/record.uri?eid=2-s2.0-84889679284&doi=10.1130%2fGES00853.1&partnerID=40&md5=5ddec971bc45590c243fbaf5968b7c8c cited By 27 F.M. McCarthy M.E. Katz U. Kotthoff J.V. Browning K.G. Miller R. Zanatta R.H. Williams M. Drljepan S.P. Hesselbo C.J. Bjerrum G.S. Mountain article Cukur2013571 This paper presents results of a multi-channel seismic reflection survey at Lake Van and provides constraints on the sedimentary evolution of the lake. The geophysical data of the lake confirm the existence of three physiographic provinces: a shelf, a slope, and a deep, relatively flat basin. The most prominent features identified on the shelf and slope are clinoforms, submerged channels, as well as closely spaced lake floor depressions, reflecting a highly variable lake-level history. The morphological depressions are interpreted as resulting from subaquatic erosion by channelized, sediment-laden currents into horizontally bedded fan sediments. Submerged channels on the eastern shelf are interpreted as meandering-slope channels, probably as a consequence of a lake-level fall that exposed the shelf area. Clinoforms on the Eastern fan may represent relict deltas formed during stationary or slightly rising lake-level intervals. Merging subsurface imaging interpretation with morphological studies of exposed sediments reveals lake-level fluctuations of several hundreds of meters during the past ca. ~550 ka. The lake has three prominent basins (Tatvan, Deveboynu, and the Northern basin) separated by basement ridges (e. g., the Northern ridge). The seismic units in the Tatvan and Northern basins are dominated by alternations of well-stratified and chaotic reflections, while the Deveboynu basin subsurface consists mainly of chaotic units. The chaotic seismic facies are interpreted as mass-flow deposits, probably triggered by earthquakes and/or rapid lake-level fluctuations. The moderate-to-high-amplitude, well-stratified facies seen in the deeper parts of the basins are interpreted as lacustrine deposits intercalated with tephra layers. The occurrence of a clinoform in the deepest part of the lake suggests a major flooding stage of Lake Van more than ~400 ka ago. Seismic profiles from the deepest part of the lake basin show remarkably uniform and continuous stratigraphic units without any major erosional feature following the flooding event, indicating that the lake was never completely dry afterward and therefore significantly older than previously suggested. © 2012 Springer-Verlag. 2013 English 14373254 10.1007/s00531-012-0816-x International Journal of Earth Sciences 102 Springer Verlag 571-585 GEOMAR Helmholtz Centre for Ocean Research Kiel, Wischhofstr. 1-3, 24148 Kiel, Germany; Department of Geosciences, University of Bremen, Bremen, Germany; Department of Geophysical Engineering, Istanbul Technical University, Ayazaga Campus, Maslak-Istanbul, Turkey; Alfred Wegener Institute for Polar and Marine Research, 27515 Bremerhaven, Germany; Eurasia Institute of Earth Sciences, Istanbul Technical University, Ayazaga Campus, Maslak-Istanbul, Turkey 2 erosion; lacustrine deposit; lake level; sedimentary sequence; seismic reflection; tephra, Lake Van; Turkey https://www.scopus.com/inward/record.uri?eid=2-s2.0-84874019371&doi=10.1007%2fs00531-012-0816-x&partnerID=40&md5=4d7b435f4bfe02c2db9f10fe7f64d573 cited By 39 D. Cukur S. Krastel F. Demirel-Schlüter E. Demirbag C. Imren M. Toker article Bellefleur2013556 The Mackenzie Delta in Canada's Northwest Territories hosts many permafrost-related gas-hydrate accumulations that were indirectly discovered or inferred from conventional hydrocarbon exploration programs. In particular, gas-hydrate intervals characterized with high saturation show high resistivity and high P-and S-wave velocity on well-log data, are typically found in sand-rich horizons. The acoustic impedance contrast between nonhydrate and hydrate-bearing sediments usually produces strong amplitude reflections on seismic data. Such a signature was previously observed onshore at Mallik, Northwestern Territories (Collett et al., 1999), on the North Slope of Alaska (Collett et al., 2011). Here, we use 2D and 3D seismic reflection data acquired by industry on Richards Island to map and characterize gas-hydrate accumulations beneath a thick permafrost area of the Mackenzie Delta (Figure 1). Specifically, we show new seismic evidences of gas-hydrate accumulations above the Ya Ya and Umiak conventional gas fields. © 2013 by The Society of Exploration Geophysicists. 2013 English 1070485X 10.1190/tle32050556.1 Leading Edge 32 Society of Exploration Geophysicists 556-563 Geological Survey of Canada, Canada 5 Acoustic impedance; Gases; Hydration; Permafrost; Petroleum prospecting; Seismic prospecting; Seismic waves; Seismology; Shear waves; Wave propagation; Well logging, Conventional hydrocarbons; High resistivity; Hydrate accumulations; Hydrate bearing sediments; North Slope of Alaska; P- and S-wave velocities; Permafrost area; Seismic evidence, Gas hydrates, detection method; gas hydrate; hydrocarbon exploration; permafrost; S-wave; seismic data; seismic reflection; well logging, Alaska; Canada; Mackenzie Delta; North Slope; Northwest Territories; Northwest Territories; Richards Island; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-84879617165&doi=10.1190%2ftle32050556.1&partnerID=40&md5=1d9e547478136f3699951306262c4d12 cited By 0 G. Bellefleur M. Riedel T. Brent article Cukur2013341 Analysis of multi-channel seismic reflection and chirp data from Lake Van (eastern Turkey) reveals various shallow gas indicators including seismic chimneys, enhanced reflections, bright spots, mud volcanoes, pockmarks, and acoustic blanking. The enhanced reflections, suggesting the presence of free gas, are most dominant and observed at more than 200 locations. They are characterized by very-high amplitude reflections and occur in both deep and shallow sedimentary sections. Some enhanced reflections are accompanied by very subtle seafloor expressions such as mounds, which may suggest active venting activity. Seismic chimneys or columnar zones of amplitude blanking have been observed in much of the surveyed area. Seismic chimneys in the study area cannot be associated with any known faults that would act as migration pathways for deep fluids. This suggests that the observed structures in Lake Van sediments allow the preferential emission of gases which might be for a large share of biogenic origin. The acoustic blanking, characterized by transparent or chaotic seismic facies, is seen in the eastern part of the lake. The lakeward edge of the acoustic blanking largely coincides with the 100m water depth contour, indicating that (past) changes of the hydrostatic pressure may be responsible for the distribution of these anomalies. Mound-like features, interpreted as mud volcanoes, occur in a few locations. The presence of these features may suggest active gas emission. Very strong amplitude anomalies or bright spots with negative polarity, indicating gas-charged zones, are also seen in a number of locations. Pockmarks are observed only in the northeastern part of the study area. The scarce occurrence of pockmarks in the study area might be ascribed to a higher permeability of the lake sediments or to the absence of the substrate/reservoir providing the critical mass of gases necessary to produce such features. Turbidites, tephra layers, and deltaic deposits have the potential to provide ideal conditions to allow the sediments to act as a gas reservoir. © 2013 Elsevier Ltd. 2013 English 02648172 10.1016/j.marpetgeo.2013.08.017 Marine and Petroleum Geology 48 341-353 GEOMAR, Helmholtz Centre for Ocean Research Kiel, Wischhofstr. 1-3, 24148 Kiel, Germany; Kiel University, Institute of Geosciences, Otto-Hanhn-Platz 1, 24118 Kiel, Germany; Eawag, Swiss Federal Institute of Aquatic Science and Technology, Department of Water Resources and Drinking Water, Überlandstrasse 133, CH-8600 Dübendorf, Switzerland; Istanbul Technical University, EMCOL and Department of Geological Engineering, 34469 Maslak, Istanbul, Turkey; Van Yüzüncü Yil Univ., Department of Geological Engineering, Van, Turkey Bright spots; Enhanced reflections; Lake vans; Pockmarks; Shallow gas, Chimneys; Hydrostatic pressure; Lakes; Sediments; Seismology; Volcanoes, Gases, deltaic deposit; facies analysis; hydrocarbon reservoir; hydrostatic pressure; lacustrine deposit; mud volcano; permeability; pockmark; seismic reflection; tephra; turbidite; venting, Lake Van; Turkey https://www.scopus.com/inward/record.uri?eid=2-s2.0-84884564316&doi=10.1016%2fj.marpetgeo.2013.08.017&partnerID=40&md5=7ee3c5446147d3f708c7c35ae8435cc8 cited By 24 D. Cukur S. Krastel Y. Tomonaga M.N. Çağatay A.F. Meydan article Mang201364 Shock experiments with pressures ranging from 3 to 30 GPa have been conducted on a mixed assemblage of hexagonal and monoclinic pyrrhotite. All samples were studied with respect to their particular shock-induced microstructures and magnetic properties at high and low temperatures. Up to 8 GPa, microstructures in shocked pyrrhotite are characterized by mechanical deformation producing a damage of the crystal structure. At pressures of 20 GPa and upward, amorphization and mechanical twinning are the dominant structural features induced by shock. Within the lower-pressure range coercivity, saturation isothermal remanent magnetization and coercivity of remanence increase with shock pressures, in agreement with more single-domain (SD)-like behavior. Simultaneously, the λ-peak of hexagonal pyrrhotite decreases and the 34 K transition of monoclinic pyrrhotite broadens and is depressed. Magnetic hardening is triggered by grain-size reduction, but also by the formation of SD within discrete multidomain grains. Planar deformation features subdivide such multidomain grains into lath-shaped domains with average sizes lying in the SD range. The planar deformation features disappear at 20 GPa and irregular, nanometer-sized "amorphous domains" occur instead. Pressure release from 30 GPa finally triggers partial melting of pyrrhotite. The sharp interfaces between molten and crystalline pyrrhotite document a rapid change of thermal conditions. Within molten pyrrhotite, quenched iron crystals occur. The presence of native iron strongly influences the magnetic properties, depending on the particular amount in the studied sample and likely affects the magnetic properties of impact lithologies on Earth and extraterrestrial material. ©2013. American Geophysical Union. All Rights Reserved. 2013 10.1029/2012GC004242 Geochemistry, Geophysics, Geosystems 14 64-85 Institut für Angewandte Geowissenschaften, Karlsruher Institut für Technologie, Adenauerring 20, Geb. 50.40, D-76131 Karlsruhe, Germany; Museum für Naturkunde, Leibniz-Institut, Humboldt Universität zu Berlin, Berlin, Germany; Laboratorium für Elektronenmikroskopie, Karlsruher Institut für Technologie, Karlsruhe, Germany 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84879807327&doi=10.1029%2f2012GC004242&partnerID=40&md5=4ee9274ee3c5d51772d1bf852c98572f cited By 21 C. Mang A. Kontny J. Fritz R. Schneider article cp-9-1271-2013 We developed a synoptic climatology for Lake El'gygytgyn, Chukotka Russia, and explored modern climate trends affecting air temperatures there to aid in paleoclimate reconstructions of a 3.6 million-year-old sediment core taken from the lake. Our self-organized mapping (SOM) approach identified 35 synoptic weather patterns, based on sea level pressure, that span the range of synoptic patterns influencing the study domain over the 1961-2009 NCEP/NCAR analysis period. We found strong seasonality in modern weather patterns, with summer weather primarily characterized by weak low pressure systems over the Arctic Ocean or Siberia and winter weather primarily characterized by strong high pressure over the Arctic Ocean and strong low pressure in the Pacific Ocean. In general, the primary source of variation in air temperatures came from the dominant patterns in each season, which we identify in the text, and nearly all of the dominant weather patterns here have shown increasing temperatures. We found that nearly all of the warming in mean annual temperature over the past 50 yr (about 3°C) occurred during sub-freezing conditions on either side of summer (that is, spring and fall). Here we found that the most summer-like weather patterns (low pressures to the north) in the shoulder seasons were responsible for much of the change. Finally, we compared the warmest 15 yr of the record (1995-2009) to the coolest (1961-1975) and found that changes in thermodynamics of weather were about 3 to 300 times more important than changes in frequency of weather patterns in controlling temperature variations during spring and fall, respectively. That is, in the modern record, general warming (local or advected) is more important by orders of magnitude than changes in storm tracks in controlling air temperature at Lake El'gygytgyn. We conclude with a discussion of how these results may be relevant to the paleoclimate reconstruction efforts and how this relevancy could be tested further. © Author(s) 2013. 2013 English 18149324 10.5194/cp-9-1271-2013 Climate of the Past 9 1271-1286 University of Colorado at Boulder, Cooperative Institute for Research in Environmental Sciences, 216 UCB, Boulder, CO 80309, United States; University of Alaska Fairbanks, Institute of Northern Engineering, Fairbanks, AK 99775, United States 3 air temperature; climate change; dominance; freezing; low pressure; paleoclimate; seasonality; sediment core; synoptic meteorology; temperature inversion; thermodynamics, Chukchi; Elgygytgyn Lake; Russian Federation https://cp.copernicus.org/articles/9/1271/2013/ cited By 9 M. Nolan E. N. Cassano J. J. Cassano article Horálek2013979 An earthquake swarm of magnitudes up to ML = 3.2 occurred in the region of West Bohemia/Vogtland (border area between Czech Republic and Germany) in autumn 2000. This swarmconsisted of nine episodic phases and lasted 4 months. We retrieved source mechanisms of 102 earthquakes with magnitudes between ML = 1.6 and 3.2 applying inversion of the peak amplitudes of direct P and SH waves, which were determined from ground motion seismograms. The investigated events cover the whole swarm activity in both time and space. We use data from permanent stations of seismic network WEBNET and from temporal stations, which were deployed in the epicentral area during the swarm; the number of stations varied from 7 to 18. The unconstrained moment tensor (MT) expression of the mechanism, which describes a general system of dipoles, that is both double-couple (DC) and non-DC sources, was applied. MTs of each earthquake were estimated by inversion of three different sets of data: P-wave amplitudes only, P- and SH-wave amplitudes and P-wave amplitudes along with the SH-wave amplitudes from a priori selected four 'base' WEBNET stations, the respective MT solutions are nearly identical for each event investigated. The resultant mechanisms of all events are dominantly DCs with only insignificant non-DC components mostly not exceeding 10 per cent. We checked reliability of the MTs in jackknife trials eliminating some data; we simulated the mislocation of hypocentre or contaminated the P- and SH-wave amplitudes by accidental errors. These tests proved stable and well constrained MT solutions. The massive dominance of the DC in all investigated events implies that the 2000 swarmconsisted of a large number of pure shears along a fault plane. The focal mechanisms indicate both oblique-normal and oblique-thrust faulting, however, the oblique-normal faulting prevails. The predominant strikes and dips of the oblique-normal events fit well the geometry of the main fault plane Nov'y Kostel (NK) and also match the strike, dip and rake of the largest ML =4.6 earthquake of a strong swarm in 1985/86. On the contrary, the 2000 source mechanisms differ substantially from those of the 1997-swarm (which took place in two fault segments at the edge of the main NK fault plane) in both the faulting and the content of non-DC components. Further, we found that the scalar seismic moment M0 is related to the local magnitude ML used by WEBNET as M0 ∝ 101.12ML, which differs from the scaling law using moment magnitude Mw, that is M0 ∝ 101.5 ML. © The Authors 2013. Article 2013 English 1365246X 10.1093/gji/ggt138 Geophysical Journal International 194 979 – 999 2 Bohemia; Czech Republic; Germany; Vogtland; Faulting; Seismic waves; Shear waves; Accidental error; Dynamics and mechanics of faulting; Earthquake source observations; Earthquake swarms; Fracture and flows; Intra-plate process; Moment magnitudes; Source mechanisms; data inversion; earthquake magnitude; earthquake swarm; faulting; focal mechanism; ground motion; intraplate process; moment tensor; P-wave; SH-wave; source parameters; Earthquakes https://www.scopus.com/inward/record.uri?eid=2-s2.0-84880280912&doi=10.1093%2fgji%2fggt138&partnerID=40&md5=0056e66f9256a130fe6dba40fcef1cab Cited by: 18; All Open Access, Bronze Open Access Josef Horálek Jan Šílený article Yadav2013965 New empirical relations are derived for source parameters of the Koyna-Warna reservoir-triggered seismic zone in Western India using spectral analysis of 38 local earthquakes in the magnitude range ML 3.5-5.2. The data come from a seismic network operated by the CSIR-National Geophysical Research Institute, India, during March 2005 to April 2012 in this region. The source parameters viz. seismic moment, source radius, corner frequency and stress drop for the various events lie in the range of 1013-1016 Nm, 0.1-0.4 km, 2.9-9.4 Hz and 3-26 MPa, respectively. Linear relationships are obtained among the seismic moment (M0), local magnitude (ML), moment magnitude (Mw), corner frequency (fc) and stress drop (Δσ). The stress drops in the Koyna-Warna region are found to increase with magnitude as well as focal depths of earthquakes. Interestingly, accurate depths derived from moment tensor inversion of earthquake waveforms show a strong correlation with the stress drops, seemingly characteristic of the Koyna-Warna region. © 2013 Springer Science+Business Media Dordrecht. 2013 English 0921030X 10.1007/s11069-013-0745-4 Natural Hazards 69 Kluwer Academic Publishers 965-979 CSIR-National Geophysical Research Institute, Hyderabad, India; National Disaster Management Authority, New Delhi, India 1 earthquake event; earthquake magnitude; earthquake trigger; focal mechanism; reservoir-induced seismicity; seismic moment; seismic zone; source parameters; spectral analysis; stress analysis; waveform analysis, India https://www.scopus.com/inward/record.uri?eid=2-s2.0-84884908631&doi=10.1007%2fs11069-013-0745-4&partnerID=40&md5=dca0b4830100b3daeb3309139da37a13 cited By 13 A. Yadav D. Shashidhar K. Mallika N.P. Rao S. Rohilla H.V.S. Satyanarayana D. Srinagesh H. Gupta article Shanahan201396 The physical, inorganic and organic geochemical and stable isotopic characteristics of lacustrine sediments can provide valuable insights into past environmental changes, provided that the environmental controls on these characteristics are well understood. In the present study, a set of 155 modern vegetation, catchment soil, river sediments and lake surface sediment samples are used to characterize the spatial patterns of TOC, TN, C/N ratios, stable isotope, major element, and particle size distributions within Lake Bosumtwi, a meromictic crater lake in West Africa. Spatial variations in sediment characteristics are strongly correlated with depth and distance from shore, reflecting the dominant influence of lake level on the relative proportions of littoral and pelagic depositional systems and their impact on the physical and geochemical properties of lacustrine sediments. This is supported by a principal component analysis, which indicates that 65% of the variance in the dataset is explained by depth-related variability in the sedimentary components. Variations in sedimentary organic matter reflect the combined influences of productivity, preservation and the relative proportions of aquatic and terrestrial organic matter sources. Grain size and Si content are dominantly influenced by the delivery of clastic materials from the watershed to the lake, whereas Fe and Ca appear to be most strongly influenced by the delivery of reduced metals and nutrients from the anoxic hypolimnion to the surface. With the exception of grain size, all of the sediment parameters record synchronous century-scale variability over the past ~2.5ka, consistent with independent evidence for changes in lake level. However, the magnitude of changes in sediment characteristics differs, reflecting different sensitivities to water depth, particularly in the deepest part of the lake basin where the sediment cores were collected. However, even the parameters with the most linear and strongly significant relationships with depth (e.g., TOC, TN) significantly overestimate the magnitude of lake level changes, suggesting that these parameters may be best suited to qualitative paleolake level reconstructions. Over the last 2 centuries, changes in C/N and δ13C became decoupled from the other geochemical proxies and the inferred rise in lake level. We hypothesize that this reflects the influence of anthropogenic land use change on the composition of terrestrial organic matter sources contributing to the lake. This result highlights the potential difficulties in reconstructing past environmental changes from indirect proxy measurements when those proxies may be subject to multiple varying controls. © 2013 Elsevier B.V. Article 2013 English 00310182 10.1016/j.palaeo.2013.01.008 Palaeogeography, Palaeoclimatology, Palaeoecology 374 96 – 109 Ashanti; Ghana; Lake Bosumtwi; West Africa; correlation; data set; environmental change; geochemical survey; lake ecosystem; land use change; organic matter; paleoenvironment; parameterization; pelagic deposit; principal component analysis; spatiotemporal analysis; stable isotope https://www.scopus.com/inward/record.uri?eid=2-s2.0-84875080379&doi=10.1016%2fj.palaeo.2013.01.008&partnerID=40&md5=3d2392c062215985ec8dbc1389cdee90 Cited by: 20 Timothy M. Shanahan Nicholas McKay Jonathan T. Overpeck John A. Peck Christopher Scholz Clifford W. Heil John King article Pérez201396 Modern lake hydrodynamics, ostracode species autecology, stable isotopes (δ18O and δ13C) of multiple ostracode species, ostracode taphonomy and sediment geochemistry were studied to improve interpretation of the late Pleistoceneeearly Holocene (~24-10 ka) stable isotope record of ostracodes in sediment core PI-6 from Lago Petén Itzá, northern Guatemala. Oxygen and carbon stable isotopes in modern and fossil species assemblages of Lago Petén Itzá were used as indicators of changes in the balance between evaporation and precipitation, past lake level and carbon source. Ostracode taphonomy was used to detect past periods of strong currents, high-energy environments, and possible partial or full mixing of the lake. The modern lake water isotopic composition displays clear seasonal differences that are independent of lake level fluctuations. Modern benthic species displayed lower δ18O and δ13C values than nektobenthic species, with differences of 3.0‰ and 5.3‰, respectively. Valves of nektobenthic species display higher values of d13C because these ostracodes live in shallower environments among abundant algae and aquatic plants, where productivity is high. The benthic species Limnocythere opesta Brehm, 1939 displayed the smallest average offset from d18O water (0.3‰) and the largest offset from δ13CDIC values (4.1‰) among studied ostracode species. Nektobenthic species Heterocypris punctata Keyser, 1975 displayed the smallest difference relative to the δ13CDIC values (0.1‰). Late Pleistoceneeearly Holocene climate conditions and water levels in Lago Petén Itzá can be summarized as follows: 1) high lake levels and cold conditions (Last Glacial Maximum [LGM], ~24-19 ka), 2) fluctuating lake levels and cold conditions (Heinrich Stadial 1 [HS1], ~19-15 ka), 3) high lake levels and warm and wetter conditions (Bølling-Allerød [BA], ~15-13 ka), 4) low lake levels and dry conditions (Younger Dryas [YD], ~13-11.5 ka) and 5) high lake levels and warm and wetter conditions (early Holocene, ~11.5-10.0 ka). Average lake level fluctuation in Lago Petén Itzá during the late Pleistoceneeearly Holocene was as much as ~25 m. Ostracode analyses suggest that the LGM was characterized by relatively low d18O (4.7 to 6.0&), and d13C values (7.1 to 6.4‰) in ostracode valves, high inferred water depths and high percentages of broken adult and juvenile valves (>66%), suggesting a high-energy environment, strong currents, partial to full mixing, downslope transport, colder water temperatures and wetter conditions. An increase in the relative abundance of the benthic species L. opesta and higher numbers of broken valves suggest heavy precipitation events during the LGM (~23.7, 21.7, 20.8 and 20.1 ka). HS1 was predominantly dry, but we identified times when lake levels were slightly higher, at the onset of the deglacial and a brief period (~17-16 ka) between HS1b and HS1a. All studied climate proxies indicate wetter and warmer conditions and lake system stability during the BA. Lake levels dropped during the YD and gradually increased during the Preboreal and early Holocene. We demonstrate that modern and fossil ostracode isotopic signatures, species assemblages and taphonomy can be used together with physical and geochemical variables in Lago Petén Itzá sediments to make high-resolution inferences about late Pleistoceneeearly Holocene environmental changes in the lowland Neotropics. © 2012 Elsevier Ltd. Article 2013 English 02773791 10.1016/j.quascirev.2012.10.044 Quaternary Science Reviews 66 Elsevier Ltd 96 – 111 Guatemala [Central America]; Lake Peten Itza; Peten; algae; Heterocypris punctata; Limnocythere; Ostracoda; Climate change; Fluid dynamics; Geochemistry; Hydrodynamics; Isotopes; Mixing; Sediments; System stability; Water levels; Autecology; Environmental change; Holocenes; Lake level changes; Neotropics; Ostracoda; Stable isotopes; abundance; autecology; benthos; fossil assemblage; fossil record; hydrodynamics; isotopic composition; lake level; Neotropical Region; ostracod; oxygen isotope; paleoecology; paleohydrology; paleolimnology; Pleistocene-Holocene boundary; seasonal variation; sediment core; stable isotope; taphonomy; Younger Dryas; Lakes https://www.scopus.com/inward/record.uri?eid=2-s2.0-84881377247&doi=10.1016%2fj.quascirev.2012.10.044&partnerID=40&md5=f1b2ebb469373e248f0aaaed0b143311 Cited by: 27 Liseth Pérez Jason Curtis Mark Brenner David Hodell Jaime Escobar Socorro Lozano Antje Schwal article Chamberlain2013106 Because of the need to understand the links and feedbacks of the carbon cycle during times of global greenhouse conditions numerous studies have focused on the Cretaceous climate. Much of what we know about this warm period in Earth's history comes from the study of ocean sediments recovered from both ocean drill cores and marine sediments exposed at the Earth's surface. In contrast, there are few studies of Cretaceous terrestrial sediments. The Songliao basin located in northeast China offers a unique opportunity to understand Cretaceous paleoclimate of terrestrial settings because it contains a nearly complete record of lacustrine sediments deposited throughout the Cretaceous and there is an active drilling program to recover core from this paleolake. We present carbon, oxygen and strontium isotopic data from ostracods collected from two drill cores (SK-1 (N) and SK-1 (S)) that cover a time interval that extends from the Turonian through the Maastrichtian. These data record robust isotopic trends with numerous carbon and oxygen isotope shifts that are both rapid and long-term. We tentatively interpret this record to reflect changes in both global climate and regional basin evolution. In the Turonian and Coniacian Qingshankou Formation we observe several carbon isotope shifts that appear to be correlative to marine isotopic records based upon timing and magnitude of the isotopic changes. We suggest that the carbon isotope record in the Songliao basin reflect the decrease in carbon isotope ratios following the strong positive excursion at the Cenomanian/Turonian boundary, a positive isotope excursion in the late Turonian, and the negative isotope shift that occurs at the Turonian/Coniacian boundary. Upward in the section, however, the marine and Songliao isotopic records diverge as sediment sources shift from the southwest, east and north to more northerly. Strontium isotopes record the change in source region as they increase markedly between the Coniacian/Santonian Yaojia and Santonian/Campanian Nenjiang Formations. As this is the first isotopic record of the Songliao basin we are cautious about many of our interpretations of these isotopic data. Yet it is clear that with tighter age constraints and focused sampling centered on many of the isotope excursions presented here will allow for a deeper understanding of the terrestrial response to changing climate and the hydrologic response to basin evolution. © 2012 Elsevier B.V. 2013 English 00310182 10.1016/j.palaeo.2012.03.020 Palaeogeography, Palaeoclimatology, Palaeoecology 385 106-124 Dept. Environmental Earth System Science, Stanford Univ., Stanford, CA 94305, United States; China University of Geosciences, Beijing, China; Dept. of Geological and Environmental Sciences, Stanford Univ., Stanford, CA 94305, United States; Dept. of Geology and Geophysics, Univ. of Wisconsin, 1215 W. Dayton St., Madison, WI 53706, United States; Dept. of Geological Sciences, Northwestern Univ., Evanston, Il 60208, United States; Earth Observatory of Singapore, Institute of Nanyang Technological University, Singapore, Singapore basin evolution; Campanian; carbon isotope; Cenomanian-Turonian boundary; Coniacian; hydrological response; Maastrichtian; marine isotope stage; ostracod; oxygen isotope; paleoclimate; Santonian; stable isotope; strontium isotope, China; Nen Basin; Songliao Basin, Coniacian; Ostracoda https://www.scopus.com/inward/record.uri?eid=2-s2.0-84879883083&doi=10.1016%2fj.palaeo.2012.03.020&partnerID=40&md5=eef96bcd818be59f03fd260c388e7a5a cited By 90 C.P. Chamberlain X. Wan S.A. Graham A.R. Carroll A.C. Doebbert B.B. Sageman P. Blisniuk M.L. Kent-Corson Z. Wang W. Chengshan article Inwood20131025 In this study, a novel application of a statistical approach is utilized for analysis of downhole logging data from Miocene-aged siliciclastic shelf sediments on the New Jersey Margin (eastern USA). A multivariate iterative nonhierarchical cluster analysis (INCA) of spectral gamma-ray logs from Integrated Ocean Drilling Program (IODP) Expedition 313 enables lithology within this siliciclastic succession to be inferred and, through comparison with the 1311 m of recovered core, a continuous assessment of depositional sequences is constructed. Signifi cant changes in INCA clusters corroborate most key stratigraphic surfaces interpreted from the core, and this result has particular value for surface recognition in intervals of poor core recovery. This analysis contributes to the evaluation of sequence stratigraphic models of large-scale clinoform complexes that predict depositional environments, sediment composition, and stratal geometries in response to sea-level changes. The novel approach of combining statistical analysis with detailed lithostratigraphic and seismic refl ection data sets will be of interest to any scientists working with downhole logs, especially spectral gamma-ray data, and also provides a reference for the strengths and weaknesses of multi component analysis applied to continental margin lithofacies. The method presented here is appropriate for evaluating successions elsewhere and also has value for hydrocarbon exploration where sequence stratigraphy is a fundamental tool. © 2013 Geological Society of America. 2013 English 1553040X 10.1130/GES00913.1 Geosphere 9 1025-1043 Department of Geology, University of Leicester, University Road, Leicester LE17RH, United Kingdom; Geosciences Montpellier, Unité Mixte de Recherche 5243, Université Montpellier 2, Bâtiment 22, 34095 Montpellier cedex, France; Institut des Sciences de la Terre, Université Joseph Fourier, BP 53, 38041 Grenoble CEDEX 9, France; Department of Geography and Geology, University of Copenhagen, OesterVoldgade 10, DK-1350 Copenhagen K, Denmark; Department of Earth and Planetary Sciences, Rutgers University, 610 Taylor Road, Piscataway, NJ 08854, United States; Unité Mixte de Recherche 6118 Centre National de la Recherche Scientifique Géosciences, Université de Rennes 1, 35042 Rennes cedex, France; Ocean Research Institute, University of Tokyo, Ocean Floor Geoscience, 1-15-1 Minamidai, Nakanoku, Tokyo, Japan; Thule Institute, University of Oulu, PO Box 7300, Oulu, FI-90014, Finland 4 cluster analysis; continental margin; core logging; depositional environment; depositional sequence; hydrocarbon exploration; lithofacies; lithology; lithostratigraphy; Miocene; Ocean Drilling Program; sea level change; sediment chemistry; sequence stratigraphy; shelf sediment; siliciclastic deposit, Atlantic Ocean; New Jersey Margin https://www.scopus.com/inward/record.uri?eid=2-s2.0-84881511164&doi=10.1130%2fGES00913.1&partnerID=40&md5=625c64323d1c35e61551064d1cf68452 cited By 12 J. Inwood J. Lofi S. Davies C. Basile C. Bjerum G. Mountain J. Proust H. Otsuka H. Valppu article Ickrath2013951 Local rotations of the stress field might serve as an indicator to characterize the physical status of individual fault segments during the seismic cycle. In this study we focus on the pre-, 2-month aftershock- and post-seismic phase of the 1999 Mw7.4 Izmit earthquake in northwestern Turkey. Using a compilation of focal mechanism data we investigate spatiotemporal changes of the stress field orientations and find distinct variations along individual fault segments. Whereas the regional stress field prior to the Izmit earthquake and following the 2-month aftershock sequence reflects a stable strike-slip regime, the early aftershock period is dominated by EW-extension below the Akyazi Basin. During the 2-month aftershock period we find significant changes from strike-slip to normal-faulting during the main shock following by a systematic backrotation to the pre-main shock stress regime. This backrotation commences first in the Akyazi Plain hosting a co-seismic slip deficit of ≤3m and propagates then further to the east towards the Karadere and Düzce faults where the Düzce Mw 7.1 main shock nucleated 87 d later. Our results confirm that spatiotemporal stress field rotations are a useful indicator for variations of the seismotectonic setting during the seismic cycle. © The Authors 2013. Published by Oxford University Press on behalf of The Royal Astronomical Society. 2013 English 0956540X 10.1093/gji/ggt409 Geophysical Journal International 196 951-956 Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences Section 3.2, Geomechanics and Rheology, Telegrafenberg, D-14473 Potsdam, Germany; Free University Berlin, Department of Earth Sciences, Malteser Strasse 74-100, 12249 Berlin, Germany 2 Earthquake dynamics; Regional stress field; Seismic cycle; Seismicity and tectonics; Seismotectonic settings; Spatial analysis; Spatio-temporal changes; Stress-field orientation, Fault slips; Stresses; Transform faults, Earthquakes, aftershock; coseismic process; focal mechanism; Kocaeli earthquake 1999; normal fault; seismicity; seismotectonics; spatial analysis; stress field; strike-slip fault; transform fault, Akyazi; Sakarya; Turkey https://www.scopus.com/inward/record.uri?eid=2-s2.0-84892472760&doi=10.1093%2fgji%2fggt409&partnerID=40&md5=00d3b3f76d7a774fc204ae814a4a403d cited By 19 M. Ickrath M. Bohnhoff F. Bulut G. Dresen article Novotný2013491 The West Bohemia and adjacent Vogtland are well known for quasi-periodical earthquake swarms persisting for centuries. The seismogenic area near Nový Kostel involved about 90 % of overall earthquake activity clustered here in space and time. The latest major earthquake swarm took place in August-September 2011. In 1994 and 1997, two minor earthquake swarms appeared in another location, near Lazy. Recently, the depth-recursive tomography yielded a velocity image with an improved resolution along the CEL09 refraction profile passing between these swarm areas. The resolution, achieved in the velocity image and its agreement with the inverse gravity modeling along the collateral 9HR reflection profile, enabled us to reveal the key structural background of these West Bohemia earthquake swarms. The CEL09 velocity image detected two deeply rooted high-velocity bodies adjacent to the Nový Kostel and Lazy focal zones. They correspond to two Variscan mafic intrusions influenced by the SE inclined slab of Saxothuringian crust that subducted beneath the Teplá-Barrandian terrane in the Devonian era. In their uppermost SE inclined parts, they roof both focal zones. The high P-wave velocities of 6,100-6,200 m/s, detected in both roofing caps, indicate their relative compactness and impermeability. The focal domains themselves are located in the almost gradient-free zones with the swarm foci spread near the axial planes of profound velocity depressions. The lower velocities of 5,950-6,050 m/s, observed in the upper parts of focal zones, are indicative of less compact rock complexes corrugated and tectonically disturbed by the SE bordering magma ascents. The high-velocity/high-density caps obviously seal the swarm focal domains because almost no magmatic fluids of mantle origin occur in the Nový Kostel and Lazy seismogenic areas of the West Bohemia/Vogtland territory, otherwise rich in the mantle-derived fluids. This supports the hypothesis of the fluid triggering of earthquake swarms. The sealed focal domains retain ascending magmatic fluids until their critical pressure and volumes accumulated cause rock micro-fractures perceived as single earthquake bursts. During a swarm period, the focal depths of these sequential events become shallower while their magnitudes grow. We assume that coalescence of the induced micro-fractures forms temporary permeability zones in the final swarm phase and the accumulated fluids release into the overburden via the adjacent fault systems. The fluid release usually occurs after the shallowest events with the strongest magnitudes ML &gt; 3. The seasonal summer declines of hydrostatic pressure in the Cheb Basin aquifer system seem to facilitate and trigger the fluid escape as happened for the 2000, 2008, and 2011 earthquake swarms. The temporary fluid release, known as the valve-fault action, influences the surface aquifer systems in various manners. In particular, we found three quantities, the strain, mantle-derived 3He content in CO2 surface sources and ground water levels, which display a 3-5 months decline before and then a similar restoration after each peak earthquake during the swarm activities. The revealed structure features are particularly important since the main Nový Kostel earthquake swarm area is proposed as a site for the ICDP project, 'Eger Rift Drilling'. © 2013 Springer Science+Business Media Dordrecht. 2013 English 01693298 10.1007/s10712-013-9239-x Surveys in Geophysics 34 Kluwer Academic Publishers 491-519 Institute of Geophysics ASCR, Prague, Czech Republic; Institute of Petroleum Engineering, TU Clausthal, Agricolastrasse 10, Clausthal-Zellerfeld, Germany 4 Aquifers; Faulting; Groundwater resources; Hydrostatic pressure; Image enhancement; Inverse problems; Refraction; Roofs; Seismic waves; Structure (composition); Tomography; Velocity; Water levels, 9hr reflection profiles; Bohemian massifs; CEL09 refraction profiles; Earthquake swarms; Gravity model; Saxothuringian, Earthquakes, earthquake magnitude; earthquake mechanism; earthquake swarm; gravity field; Hercynian orogeny; hydrostatic pressure; inverse analysis; refraction; slab; subduction; tomography, Bohemian Massif; Cheb Basin; Czech Republic; Germany; Karlovarsky; Vogtland https://www.scopus.com/inward/record.uri?eid=2-s2.0-84879844941&doi=10.1007%2fs10712-013-9239-x&partnerID=40&md5=b7a11f44e7385a6ea0fefcee647cad13 cited By 3 M. Novotný A. Špičák F.H. Weinlich article Glombitza2013 As part of the International Continental Drilling Program deep lake drilling project PaleoVan, we investigated sulfate reduction (SR) in deep sediment cores of the saline, alkaline (salinity 21.4%, alkalinity 155 m mEq-1, pH 9.81) Lake Van, Turkey. The cores were retrieved in the Northern Basin (NB) and at Ahlat Ridge (AR) and reached a maximum depth of 220 m. Additionally, 65-75 cm long gravity cores were taken at both sites. SR rates (SRR) were low (≥22 nmol cm-3 day-1) compared to lakes with higher salinity and alkalinity, indicating that salinity and alkalinity are not limiting SR in Lake Van. Both sites differ significantly in rates and depth distribution of SR. In NB, SRR are up to 10 times higher than at AR. SR could be detected down to 19 mblf (meters below lake floor) at NB and down to 13 mblf at AR. Although SRR were lower at AR than at NB, organic matter (OM) concentrations were higher. In contrast, dissolved OM in the pore water at AR contained more macromolecular OM and less low molecular weight OM. We thus suggest, that OM content alone cannot be used to infer microbial activity at Lake Van but that quality of OM has an important impact as well. These differences suggest that biogeochemical processes in lacustrine sediments are reacting very sensitively to small variations in geological, physical, or chemical parameters over relatively short distances. © 2013 Glombitza, Stockhecke, Schubert, Vetter and Kallmeyer. 2013 English 1664302X 10.3389/fmicb.2013.00209 Frontiers in Microbiology 4 Frontiers Research Foundation Geomicrobiology Group, Institute of Earth and Environmental Sciences, University of Potsdam, Potsdam, Germany; Department of Surface Waters-Research and Management, Eawag, Swiss Federal Institute of Aquatic Science and Technology, Dubendorf, Switzerland; Department of Surface Waters-Research and Management, Eawag, Swiss Federal Institute of Aquatic Science and Technology, Kastanienbaum, Switzerland; Section 4.3 Organic Geochemistry, Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences, Potsdam, Switzerland; Section 4.5 Geomicrobiology, Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences, Telegrafenberg, 14473 Potsdam, Germany; Center for Geomicrobiology, Aarhus University, Ny Munkegade 114, 8000 Aarhus, Denmark JUL organic matter; sulfate, alkalinity; article; biogeochemical cycling; biosphere; carbon nitrogen ratio; ion pair chromatography; lake ecosystem; limit of quantitation; macromolecule; mathematical model; microbial activity; nonhuman; particle resuspension; pH measurement; reduction; reduction kinetics; relative density; salinity; sedimentology; sulfate reduction; total organic carbon; water sampling https://www.scopus.com/inward/record.uri?eid=2-s2.0-84885341712&doi=10.3389%2ffmicb.2013.00209&partnerID=40&md5=48044a2e841ce99204d1cabc98342e68 cited By 37 C. Glombitza M. Stockhecke C.J. Schubert A. Vetter J. Kallmeyer book koptyug2013sustainable 2013 6 Springer Science & Business Media Valentin A Koptyug Martin Uppenbrink article Fu2013875 Lake Qinghai, in North China, is the largest interior plateau lake in Central Asia, and is sensitive to climate change and the environmental effects of Tibetan Plateau uplift. We have obtained an almost continuous 626 m long sediment core from an in-filled part of the southern lake basin, which documents both the age of the origin of the lake and the evolution of the East Asian monsoon during the Late Cenozoic. High-resolution magnetostratigraphy provides a chronology back to ca. 5.1 Ma. Analysis of lithofacies and depositional environments reveal that the change from eolian to lacustrine facies occurred at ca. 4.63 Ma, corresponding to a shift from an arid or semi-arid to a more humid climate, which resulted in the origin of Lake Qinghai. Changes in sediment lithology and mean grain size indicate that the lake level fluctuated considerably, superimposed on a long-term trend from higher to lower levels in response to variations in the East Asian Monsoon. This archive is a significant additional source of information on regional and global environmental change, complementing the existing records from north China, which are mainly based on analysis of loess deposits. © 2013 Geological Society of America. Article 2013 English 19432682 10.1130/G34418.1 Geology 41 875 – 878 8 China; Qinghai; Qinghai Lake; Qinghai-Xizang Plateau; Climate change; Geochronology; Lithology; Sediments; Tectonics; Depositional environment; East Asian monsoon; Global environmental change; High resolution; Long-term trend; Magnetostratigraphy; Mean-grain size; Tibetan Plateau; age determination; Cenozoic; chronology; climate variation; depositional environment; environmental change; grain size; lithofacies; lithology; loess; magnetostratigraphy; monsoon; paleoclimate; sediment core; Lakes https://www.scopus.com/inward/record.uri?eid=2-s2.0-84888816690&doi=10.1130%2fG34418.1&partnerID=40&md5=9e35ea8a8946f8f5850ae4ff88fd0654 Cited by: 43 Chaofeng Fu ZhiSheng An Xiaoke Qiang Jan Bloemendal YouGui Song Hong Chang conference Dubreuil-Boisclair2013 In the last decades, permafrost gas hydrates have beneficiated from an increasing attention among researchers and industries around the world. However, little work has been done on characterizing this resource at the reservoir scale. In this study, we used cutting edge stochastic inversion software and we developed a cascade stochastic Bayesian algorithm to simulate the gas hydrate grade (product of porosity and gas hydrate saturation) on a 3D seismic cube at the Mallik field, in the Mackenzie Delta, Canada. Firstly, the 3D seismic data are stochastically inverted for acoustic impedance leading to multiple high-resolution AI realizations conditioned to the seismic and the well-log data from wells 2L- and 5L-38. Secondly, a petrophysical inversion is performed in a stochastic Bayesian framework using gas hydrate grade logs as hard data, and randomly selected AI scenarios as secondary data. For the later inversion, an in-situ petrophysical relationship linking gas hydrate grades to acoustic impedance is built using upscaled well data. The results are thus multiple 3D gas hydrate grade realizations conditioned to all available data, and reflecting a great part of the model uncertainty. These models allow calculating the total gas volume with its associated uncertainty for the studied region. 2013 English 10.3997/2214-4609.20131156 75th EAGE Conference and Exhibition Incorporating SPE EUROPEC 2013 European Association of Geoscientists and Engineers, EAGE INRSs, Canada; INRS-ETE, Canada; GSC, Canada; Ecole Polytechnique de Montreal, Canada Acoustic impedance; Acoustic logging; Gases; Hydration; Petrophysics; Seismology; Stochastic systems; Uncertainty analysis, 3D seismic data; Bayesian algorithms; Bayesian frameworks; Gas hydrate saturations; High resolution; Model uncertainties; Petrophysical relationship; Secondary datum, Gas hydrates https://www.scopus.com/inward/record.uri?eid=2-s2.0-85085403207&doi=10.3997%2f2214-4609.20131156&partnerID=40&md5=3e2f7f28947ce8c59e0ee238fb613d58 cited By 0 C. Dubreuil-Boisclair E. Gloaguen G. Bellefleur D. Marcotte article Buylaert201370 We have measured and tested a luminescence chronology for the PASADO core 5022-1D from the maar lake of Laguna Potrok Aike. Because of unsuitable quartz OSL characteristics, sand-sized K-feldspar extracts were chosen as a dosimeter and the dose was measured using a post-IR IRSL (pIRIR290) measurement protocol. Using this approach we were able to access a stable signal and thus avoid the ubiquitous problem of feldspar signal instability. Extensive laboratory tests show that the chosen pIRIR290 protocol is applicable to these samples. We also developed a new criterion based on known relative bleaching rates of the conventional IRSL signal (IR50) and the pIRIR290 signal and the relationship between resulting equivalent doses; this is used to identify and reject poorly bleached samples. Eighteen samples out of 47 were rejected based on this criterion, without reference to absolute doses or stratigraphy; the resulting age-depth profile is self-consistent, increases smoothly with depth and is in agreement with independent age control based on volcanic ash layers (Reclús, Mt Burney and Hudson tephras) at the top and middle of the core. Our new luminescence chronology suggests that the 5022-1D core reaches back to ~65ka at ~96m below lake floor. © 2013 Elsevier Ltd. Article 2013 10.1016/j.quascirev.2013.03.018 Quaternary Science Reviews 71 70 – 80 Argentina; Laguna Potrok Aike; Santa Cruz [Argentina]; Bleaching; Cleaning; Feldspar; Lakes; Quartz; Stratigraphy; ICDP-project PASADO; Independent age control; K-feldspar; Laguna potrok aike; Luminescence dating; Measurement protocol; Post-IR IRSL; Signal instabilities; bleaching; chronology; feldspar; luminescence dating; signal; volcanic ash; Luminescence https://www.scopus.com/inward/record.uri?eid=2-s2.0-84878917033&doi=10.1016%2fj.quascirev.2013.03.018&partnerID=40&md5=afbbbb2c8217cda9c5a9a9cf956386d5 Cited by: 67 J.-P. Buylaert A.S. Murray R. Sohbati C. Ohlendorf C. Thiel S. Wastegård B. Zolitschka article Zierenberg2013327 The Iceland Deep Drilling Project Well 1 was designed as a 4- to 5-km-deep exploration well with the goal of intercepting supercritical hydrothermal fluids in the Krafla geothermal field, Iceland. The well unexpectedly drilled into a high-silica (76.5 % SiO2) rhyolite melt at approximately 2.1 km. Some of the melt vesiculated while extruding into the drill hole, but most of the recovered cuttings are quenched sparsely phyric, vesicle-poor glass. The phenocryst assemblage is comprised of titanomagnetite, plagioclase, augite, and pigeonite. Compositional zoning in plagioclase and exsolution lamellae in augite and pigeonite record changing crystallization conditions as the melt migrated to its present depth of emplacement. The in situ temperature of the melt is estimated to be between 850 and 920 °C based on two-pyroxene geothermometry and modeling of the crystallization sequence. Volatile content of the glass indicated partial degassing at an in situ pressure that is above hydrostatic (~16 MPa) and below lithostatic (~55 MPa). The major element and minor element composition of the melt are consistent with an origin by partial melting of hydrothermally altered basaltic crust at depth, similar to rhyolite erupted within the Krafla Caldera. Chondrite-normalized REE concentrations show strong light REE enrichment and relative flat patterns with negative Eu anomaly. Strontium isotope values (0.70328) are consistent with mantle-derived melt, but oxygen and hydrogen isotope values are depleted (3.1 and -118 ‰, respectively) relative to mantle values. The hydrogen isotope values overlap those of hydrothermal epidote from rocks altered by the meteoric-water-recharged Krafla geothermal system. The rhyolite melt was emplaced into and has reacted with a felsic intrusive suite that has nearly identical composition. The felsite is composed of quartz, alkali feldspar, plagioclase, titanomagnetite, and augite. Emplacement of the rhyolite magma has resulted in partial melting of the felsite, accompanied locally by partial assimilation. The interstitial melt in the felsite has similar normalized SiO2 content as the rhyolite melt but is distinguished by higher K2O and lower CaO and plots near the minimum melt composition in the granite system. Augite in the partially melted felsite has re-equilibrated to more calcic metamorphic compositions. Rare quenched glass fragments containing glomeroporphyritic crystals derived from the felsite show textural evidence for resorption of alkali feldspar and quartz. The glass in these fragments is enriched in SiO2 relative to the rhyolite melt or the interstitial felsite melt, consistent with the textural evidence for quartz dissolution. The quenching of these melts by drilling fluids at in situ conditions preserves details of the melt-wall rock interaction that would not be readily observed in rocks that had completely crystallized. However, these processes may be recognizable by a combination of textural analysis and in situ analytical techniques that document compositional heterogeneity due to partial melting and local assimilation. © 2012 Springer-Verlag. 2013 English 00107999 10.1007/s00410-012-0811-z Contributions to Mineralogy and Petrology 165 Springer Verlag 327-347 Department of Geology, University of California-Davis, Davis, CA, 95616, United States; Lawrence Livermore National Labs, 7000 East Avenue, Livermore, CA, 94550, United States; U.S. Geological Survey, 345 Middlefield Rd., Menlo Park, CA, 94025, United States; Iceland GeoSurvey (ISOR), Grensásvegur 9, IS 108 Rekjavik, Iceland; Department of Geological and Environmental Sciences, Stanford University, Stanford, CA, 94305, United States; Natural History Museum of Denmark, Copenhagen University, Øster Voldgrad 5-7, 1350 København K, Denmark; Department of Geological Sciences, 1272 University of Oregon, Eugene, OR, 97403, United States; HS Orka hf, Brekkustigur 36, IS 260 Reykjanesbær, Iceland; Department of Earth Sciences, University of California-Riverside, Riverside, CA, 92521, United States 2 augite; basalt; chemical composition; deep drilling; emplacement; geothermal system; hydrogen isotope; hydrothermal fluid; partial melting; phenocryst; pigeonite; plagioclase; rare earth element; rhyolite; stable isotope; strontium isotope; titanomagnetite; zoning, Iceland; Krafla https://www.scopus.com/inward/record.uri?eid=2-s2.0-84872796536&doi=10.1007%2fs00410-012-0811-z&partnerID=40&md5=08bc4157924fc4ff28489112ec696fb6 cited By 51 R.A. Zierenberg P. Schiffman G.H. Barfod C.E. Lesher N.E. Marks J.B. Lowenstern A.K. Mortensen E.C. Pope D.K. Bird M.H. Reed G.Ó. Fridleifsson W.A. Elders article Fang20131303 The stratigraphic utility of carbon-isotope values from terrestrial organic matter is explored for Miocene siliciclastic sediments of the shallow shelf, New Jersey margin, USA (Integrated Ocean Drilling Program [IODP] Expedition 313). These shallow marine strata, rich in terrestrial organic matter, provide a record of deposition equivalent to the Monterey event, a prolonged interval of time characterized by relatively positive carbon-isotope values recorded from foraminiferal carbonate in numerous oceanic settings. Coherent stratigraphic trends and short-term isotopic excursions are observed consistently in palynological preparation residues, concentrated woody phytoclasts, and individually picked woody phytoclasts obtained from the New Jersey sediments. A bulk organic matter curve shows somewhat different stratigraphic trends but, when corrected for mixing of marine-terrestrial components on the basis of measured C/N ratios, a high degree of conformity with the woody phytoclast record is observed. However, assuming that the correlations based on strontium-isotope values and biostratigraphy are correct, the carbon-isotope record from the New Jersey margin contrasts with that previously documented from oceanic settings (i.e., lack of positive excursion of carbonisotope values in terrestrial organic matter through the Langhian Stage). Factors that may potentially bias local terrestrial carbonisotope records include reworking from older deposits, degradation and diagenesis, as well as environmental factors affecting vegetation in the sediment source areas. These possible factors are assessed on the basis of pyrolysis data, scanning electron microscope observations, and comparison to palynological indices of environmental change. Some evidence is found for localized degradation and/or reworking of older woody phytoclasts, but where such processes have occurred they do not readily explain the observed carbon-isotope values. It is concluded that the overall carbon-isotope signature for the exchangeable carbon reservoir is distorted, to the extent that the Monterey event excursion is not easily identifiable. The most likely explanation is that phytoclast reworking has indeed occurred in clinoform toe-ofslope facies, but the reason for the resulting relatively heavy carbon-isotope values in the Burdigalian remains obscure. © 2013 Geological Society of America. 2013 English 1553040X 10.1130/GES00851.1 Geosphere 9 1303-1318 Department of Earth Sciences, University of Oxford, South Parks Road, Oxford OX1 3AN, United Kingdom; Camborne School of Mines, College of Engineering, Mathematics and Physical Sciences, University of Exeter, Tremough Campus, Penryn, Cornwall TR10 9EZ, United Kingdom; Nordic Centre for Earth Evolution (NordCEE), Department of Geosciences and Natural Resource Management, University of Copenhagen, Øster Voldgade 10, DK-1350, Copenhagen K, Denmark; Institut für Geologie, Universität Hamburg, Bundesstrasse 55, 20146 Hamburg, Germany; Department of Earth Sciences, Brock University, 500 Glenridge Avenue, St. Catharines, Ontario L2S 3A1, Canada; School of Earth and Space Science, Peking University, 5 Yiheyuan Road, Beijing 100871, China; Research Laboratory for Archaeology and History of Art (RLAHA), University of Oxford, South Parks Road, Oxford OX1 3QY, United Kingdom 5 carbon isotope; deposition; environmental factor; Miocene; mixing; organic matter; palynology; pyrolysis; shelf sediment; siliciclastic deposit; stratigraphy; strontium isotope, New Jersey; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-84885167117&doi=10.1130%2fGES00851.1&partnerID=40&md5=d431e4f0151f009b84cf03f1da1e5ff5 cited By 8 L. Fang C.J. Bjerrum S.P. Hesselbo U. Kotthoff F.M.G. McCarthy B. Huang P.W. Ditchfield article Kietäväinen201337 Article 2013 10.1016/j.apgeochem.2012.10.013 Applied Geochemistry 32 37 – 51 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84876308246&doi=10.1016%2fj.apgeochem.2012.10.013&partnerID=40&md5=ff0458c69bff4d9a1e8bed0d61ddbffd Cited by: 44 Riikka Kietäväinen Lasse Ahonen Ilmo T. Kukkonen Nina Hendriksson Mari Nyyssönen Merja Itävaara article cp-9-2413-2013 2013 10.5194/cp-9-2413-2013 Climate of the Past 9 2413-2432 6 https://cp.copernicus.org/articles/9/2413/2013/ N. R. Nowaczyk E. M. Haltia D. Ulbricht V. Wennrich M. A. Sauerbrey P. Rosen H. Vogel A. Francke C. Meyer-Jacob A. A. Andreev A. V. Lozhkin article Nowaczyk20132413 A 318-metre-long sedimentary profile drilled by the International Continental Scientific Drilling Program (ICDP) at Site 5011-1 in Lake El’gygytgyn, Far East Russian Arctic, has been analysed for its sedimentologic response to global climate modes by chronostratigraphic methods. The 12 km wide lake is sited off-centre in an 18 km large crater that was created by the impact of a meteorite 3.58 Ma ago. Since then sediments have been continuously deposited. For establishing their chronology, major reversals of the earth’s magnetic field provided initial tie points for the age model, confirming that the impact occurred in the earliest geomagnetic Gauss chron. Various stratigraphic parameters, reflecting redox conditions at the lake floor and climatic conditions in the catchment were tuned synchronously to Northern Hemisphere insolation variations and the marine oxygen isotope stack, respectively. Thus, a robust age model comprising more than 600 tie points could be defined. It could be shown that deposition of sediments in Lake El’gygytgyn occurred in concert with global climatic cycles. The upper ∼ 160 m of sediments represent the past 3.3 Ma, equivalent to sedimentation rates of 4 to 5 cm ka−1, whereas the lower 160 m represent just the first 0.3 Ma after the impact, equivalent to sedimentation rates in the order of 45 cm ka−1. This study also provides orbitally tuned ages for a total of 8 tephras deposited in Lake El’gygytgyn. © Author(s) 2013. 2013 English 18149324 10.5194/cp-9-2413-2013 Climate of the Past 9 Copernicus GmbH 2413-2432 Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences, Section 5.2 – Climate Dynamics and Landscape Evolution, Telegrafenberg, Potsdam, 14473, Germany; University of Cologne, Institute of Geology and Mineralogy, Zülpicher Straße 49A, Köln, 50674, Germany; Umeå University, Climate Impacts Research Centre (CIRC), Abisko, 981 07, Sweden; NEISRI, Russian Academy of Science, Magadan, 685000, Russian Federation; University of Turku, Department of Geography and Geology, Section of Geology, Turku, 20014, Finland; Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences, Centre for Geoinformation Technology CeGIT, Telegrafenberg, Potsdam, 14473, Germany; Institute of Geological Sciences, University of Bern, Baltzerstraße 1+3, Bern, Switzerland; Umeå University, Ecology and Environmental Sciences, Abisko, 981 07, Sweden 6 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85037679435&doi=10.5194%2fcp-9-2413-2013&partnerID=40&md5=15f42d5fd40475fe4f6f4741b6a61533 cited By 53 N.R. Nowaczyk E.M. Haltia D. Ulbricht V. Wennrich M.A. Sauerbrey P. Rosen H. Vogel A. Francke C. Meyer-Jacob A.A. Andreev A.V. Lozhkin article Deng201344 The Cretaceous was a period of great environmental, biological and geodynamical change, but a paucity of an accurate time frame for continental strata has prevented our understanding of the terrestrial processes and the integration of marine and terrestrial records. Here we present an integrated chronology for the terrestrial Upper Cretaceous in East Asia based on new high-resolution magnetostratigraphic results and previously published SIMS U-Pb zircon analyses of the Cretaceous Continental Scientific Drilling borehole sequence from the Songliao Basin in northeast China (hereafter termed CCSD-SK-I), which consists of a sedimentary sequence from the upper Quantou Formation (K2q) to the Mingshui Formation (K2m). Correlation to the geomagnetic polarity timescale was achieved by combining magnetostratigraphic and SIMS U-Pb zircon geochronologic data, and lithostratigraphy. Our correlation suggests that the CCSD-SK-I sedimentary sequence spans from the upper chron C34n to chron C29r. The age of the sedimentary sequence from the upper Quantou Formation (K2q) to the Mingshui Formation (K2m) in the Songliao Basin can thus be constrained to an interval from the Turonian to the Maastrichtian ages. In addition, our correlation puts the Cretaceous-Paleogene boundary in the upper part of Member 2 of the Mingshui Formation (K2m2). The constructed comprehensive chronology allows the precise correlation of the terrestrial Upper Cretaceous of the Songliao Basin to marine strata as well as other continental sequences. © 2012 Elsevier B.V. 2013 English 00310182 10.1016/j.palaeo.2012.07.028 Palaeogeography, Palaeoclimatology, Palaeoecology 385 44-54 State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China; Key Laboratory of the Earth's Deep Interior, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China borehole; Cretaceous-Tertiary boundary; drilling; geochronology; geodynamics; geological record; geomagnetic field; lithostratigraphy; Maastrichtian; magnetostratigraphy; sedimentary sequence; stratigraphic correlation; Turonian; uranium-lead dating, China; Songliao Basin https://www.scopus.com/inward/record.uri?eid=2-s2.0-84879869248&doi=10.1016%2fj.palaeo.2012.07.028&partnerID=40&md5=bc396d6ae27ccd82149713d8b458ffad cited By 116 C.L. Deng H.Y. He Y.X. Pan R.X. Zhu article Gao2013162 Clay mineralogy of a 60. m thick section of the middle Mingshui Formation (upper Campanian to lower Maastrichtian) from the SKIn borehole (Songliao Basin in NE China) has been studied to assess the palaeoclimate and provenance. The sedimentary succession is composed of shore to shallow lacustrine mudstones and siltstones in the lower part, and meandering fluvial sandstone-mudstone sequences in the upper part. The clay mineral assemblage is characterized by the predominance of smectitic minerals, with some exceptions of illite-rich layers, and trace amounts of kaolinite and chlorite. The high smectite content (>. 90% on average) in lacustrine sediments could source from erosion of smetitic soils and volcanic materials in source areas. The Lesser Xing'an-Zhangguangcai Range was the potential provenance area for the sediments, with volcanic activity occurring at ~. 70. Ma, when the temperate semi-humid palaeoclimate was favorable for the clay formation. Smectite presented in meandering fluvial sandstones is of early diagenetic origin, formed by hydrolysis and alteration of primary minerals after deposition. Illite in overbank deposits is interpreted as a result of erosion of granitic rocks and sorting in sedimentation processes. The clay mineralogy of the studied strata contains information on palaeoclimate and provenance, although early diagenetic processes may have influenced the mineralogical composition in some intervals of sandstones. © 2012 Elsevier B.V. 2013 English 00310182 10.1016/j.palaeo.2012.10.038 Palaeogeography, Palaeoclimatology, Palaeoecology 385 162-170 State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing 100083, China; School of the Earth Science and Resources, China University of Geosciences, Beijing 100083, China; State Key Laboratory of Marine Geology, Tongji University, Shanghai 200092, China Campanian; diagenesis; hydrolysis; illite; kaolinite; lacustrine deposit; Maastrichtian; mudstone; paleoclimate; provenance; siltstone; smectite, China; Heilongjiang; Xiao Hinggan Mountains https://www.scopus.com/inward/record.uri?eid=2-s2.0-84879853702&doi=10.1016%2fj.palaeo.2012.10.038&partnerID=40&md5=692432e6396d1248e5b4e259041d721c cited By 27 Y. Gao C. Wang Z. Liu B. Zhao X. Zhang article Hahn2013154 Total organic carbon, total inorganic carbon, biogenic silica content and total organic carbon/total nitrogen ratios of the Laguna Potrok Aike lacustrine sediment record are used to reconstruct the environmental history of south-east Patagonia during the past 51ka in high resolution. High lake level conditions are assumed to have prevailed during the Last Glacial, as sediments are carbonate-free. Increased runoff linked to permafrost and reduced evaporation due to colder temperatures and reduced influence of Southern Hemispheric Westerlies (SHW) may have caused these high lake levels with lake productivity being low and organic matter mainly of algal or cyanobacterial origin. Aquatic moss growth and diatom blooms occurred synchronously with southern hemispheric glacial warming events such as the Antarctic A-events, the postglacial warming following the LGM and the Younger Dryas chronozone. During these times, a combination of warmer climatic conditions with related thawing permafrost could have increased the allochthonous input of nutrients and in combination with warmer surface waters increased aquatic moss growth and diatom production. The SHW were not observed to affect southern Patagonia during the Last Glacial. The Holocene presents a completely different lacustrine system because (a) permafrost no longer inhibits infiltration nor emits meltwater pulses and (b) the positioning of the SHW over the investigated area gives rise to strong and dry winds. Under these conditions total organic carbon, total organic carbon/total nitrogen ratios and biogenic silica cease to be first order productivity indicators. On the one hand, the biogenic silica is influenced by dissolution of diatoms due to higher salinity and pH of the lake water under evaporative stress characterizing low lake levels. On the other hand, total organic carbon and total organic carbon/total nitrogen profiles are influenced by reworked macrophytes from freshly exposed lake level terraces during lowstands. Total inorganic carbon remains the most reliable proxy for climatic variations during the Holocene as high precipitation of carbonates can be linked to low lake levels and high autochthonous production. The onset of inorganic carbon precipitation has been associated with the southward shift of the SHW over the latitudes of Laguna Potrok Aike. The refined age-depth model of this record suggests that this shift occurred around 9.4cal.kaBP. © 2012 Elsevier Ltd. Article 2013 10.1016/j.quascirev.2012.09.015 Quaternary Science Reviews 71 154–s166 Argentina; Laguna Potrok Aike; Patagonia; Santa Cruz [Argentina]; algae; Bacillariophyta; Bryophyta; Cyanobacteria; Biogeochemistry; Biological materials; Carbonates; Fourier transform infrared spectroscopy; Glacial geology; Lakes; Nitrogen; Permafrost; Phytoplankton; Sediments; Silica; Argentina; Biogenic silica; Diffuse reflectance fourier transform infrared; ICDP project PASADO; Lake levels; Patagonia; Primary productivity; algal bloom; allochthon; carbon; carbonate; climate change; climate conditions; FTIR spectroscopy; global warming; growth rate; infiltration; latitude; moss; paleoenvironment; permafrost; primary production; proxy climate record; reconstruction; sediment analysis; silica; Southern Hemisphere; surface water; temperature effect; Organic carbon https://www.scopus.com/inward/record.uri?eid=2-s2.0-84878930433&doi=10.1016%2fj.quascirev.2012.09.015&partnerID=40&md5=2ab6a8b8322adf4a5b5c7b805f45d129 Cited by: 42 A. Hahn P. Kliem C. Ohlendorf B. Zolitschka article Cunningham2013408 The Last Interglacial Period (LIP) is often regarded as a good analogue for potential climatic conditions under predicted global warming scenarios. Despite this, there is still debate over the nature, duration and frequency of climatic changes during this period. One particularly contentious issue has been the apparent evidence of climatic instability identified in many marine cores but seemingly lacking from many terrestrial archives, especially within the Arctic, a key region for global climate change research. In this paper, geochemical records from Lake El'gygytgyn, north-eastern Russia, are used to infer past climatic changes during the LIP from within the high Arctic. With a sampling resolution of ~. 20-~. 90. years, these records offer the potential for detailed, high-resolution palaeoclimate reconstruction. This study shows that the LIP commenced in central Chukotka ~. 129. thousand years ago (ka), with the warmest climatic conditions occurring between ~. 128 and 127. ka before being interrupted by a short-lived cold reversal. Mild climatic conditions then persisted until ~. 122. ka when a marked reduction in the sedimentation rate suggests a decrease in precipitation. A further climatic deterioration at ~. 118. ka marks the return to glacial conditions. This study highlights the value of incorporating several geochemical proxies when inferring past climatic conditions, thus providing the potential to identify signals related to environmental change within the catchment. We also demonstrate the importance of considering how changes in sedimentation rate influence proxy records, in order to develop robust palaeoenvironmental reconstructions. © 2013 Elsevier B.V. 2013 English 00310182 10.1016/j.palaeo.2013.06.009 Palaeogeography, Palaeoclimatology, Palaeoecology 386 408-414 Climate Impacts Research Centre (CIRC), Umeå University, SE-98107 Abisko, Sweden; University of Cologne, Institute of Geology and Mineralogy, Zuelpicher Str. 49a, D-50674 Cologne, Germany; University of Bern, Institute of Geological Sciences and Oeschger Centre for Climate Change Research, Baltzerstr, 1+3, CH-3012 Bern, Switzerland; GeoForschungsZentrum Potsdam, Section 3.3, Telegrafenberg, D-14473 Potsdam, Germany; Department of Chemistry, Umeå University, SE-90187 Umeå, Sweden climate variation; geochemical method; global warming; Last Interglacial; marine record; paleoenvironment; paleolimnology; primary production; reconstruction; sediment core; sedimentation rate, Chukchi; Elgygytgyn Lake; Russian Federation https://www.scopus.com/inward/record.uri?eid=2-s2.0-84881542454&doi=10.1016%2fj.palaeo.2013.06.009&partnerID=40&md5=176f552ae5fde8555715a0c66246b6f8 cited By 8 L. Cunningham H. Vogel N. Nowaczyk V. Wennrich O. Juschus P. Persson P. Rosen article Kämpf201371 In the western Eger Rift (ER) area along the Počatky-Plesná fault zone (PPZ) CO2 degassing occurs predominantly within two mofette fields Bublák and Hartoušov. We studied 27 wet mofettes belonging to these mofette fields for gas emission rates repeatedly between 2007 and 2009 and selected mofettes for gas composition and isotope ratios (δ13C, 3He/4He). Detailed ground mapping along the PPZ provided further two separated diffuse degassing structures (DDS) within the mofette fields Hartoušov and Bublák. The DDS Hartoušov was studied in detail by measurements of 682 CO2 soil gas concentrations, 762 CO2 soil gas fluxes (max. 10 grid spacing) and partly by analyses of isotope ratios (13C/12C, 3He/4He) of soil gas. At the DDS Hartoušov the total CO2 soil flux yielded 1.559tm-2d-1 in spring 2009 and the CO2 emission rate at the wet mofettes of Hartoušov mofette field yielded 0.62td-1. The total CO2 discharge of the 27 wet mofettes was 3.75t d-1.At sites with high CO2 soil flux, the portion of mantle-derived helium is in the same range as the releasing at wet mofettes; both cover the signature of the subcontinental mantle. Also, the δ13C values analysed in the gas releasing from wet mofettes and those analysed in soil gas are nearly the same. Taking in account a biogenic soil CO2 flux of 25gm-2d-1 as background, the mantle-derived CO2 flux yielded approximately 1566tm-2d-1. As a result of the CO2 flux mapping of the DDS Hartoušov, it could be proved that 97.4% of the released soil CO2 (1.518tm-2d-1) stems from sites with CO2 fluxes higher than 500gm-2d-1-pointing to dominantly fault-related CO2 release.At the central mofette Bublák (B2), the gas emission rate was determined for the first time in 1993. Measurements repeated between 2007 and 2009 showed a clear increase in the gas emission rate of more than 40%, correlating well with the increase of the 3He/4He ratios from 5Ra to approximately 6Ra between 1993 and 2008 at this location (Bräuer et al., 2009).The Bublák mofette field is characterised by the highest CO2 emission rate along the PPZ, and in combination with the helium isotope signature of the European subcontinental mantle, this area was identified as a deep-reaching fluid injection zone. © 2012 Elsevier B.V. Article 2013 English 00092541 10.1016/j.chemgeo.2012.08.005 Chemical Geology 339 71 – 83 Czech Republic; Degassing; Gas emissions; Geologic models; Helium; Isotopes; Particulate emissions; Radium; Soils; C values; Continental rift; Czech Republic; Diffuse degassing; Eger Rift; Emission rates; Fault zone; Fluid injections; Gas compositions; Gas emission rates; Gas releasing; Grid-spacings; Ground mapping; Helium isotopes; Isotope ratio; ; Measurements of; Soil CO; Soil flux; Soil gas; Soil gas concentration; Subcontinental mantle; Total CO; carbon dioxide; carbon emission; carbon flux; degassing; diffusion; fluid injection; helium isotope; isotopic analysis; isotopic composition; isotopic ratio; rifting; soil gas; Carbon dioxide https://www.scopus.com/inward/record.uri?eid=2-s2.0-84873748876&doi=10.1016%2fj.chemgeo.2012.08.005&partnerID=40&md5=204b2364c33bb4beb520b1cfa0dbb787 Cited by: 71 Horst Kämpf Karin Bräuer Jens Schumann Kai Hahne Gerhard Strauch article Schleicher20131039 To understand the role of hydrated clay minerals in active fault systems, a humidity chamber connected to an X-ray diffractometer was used to determine the adsorption of water onto and/or into the crystal structure of smectite. This new type of analysis was carried out under specific temperature and humidity conditions, using powdered clay size fractions (< 2 μm) of rock samples from the San Andreas Fault (USA) and the Nankai Trough (Japan). Pressure cannot be controlled, but does not significantly affect clay swelling at shallow conditions. Air-dried samples show a discrete smectite phase that swells after traditional ethylene glycolation to an interlayer distance of 1.5 and 1.7 nm. Using the humidity chamber, however, the samples show a shorter interlayer distance, between 1.09 and 1.54 nm. Based on our analysis, we show that (i) ethylene glycol overestimates the size of the interlayer space, and therefore water content, so is a crude maximum only; (ii) interlayer swelling occurs in smectite clay minerals at all temperatures between 25 and 95°C; and (iii) particle orientation increases with increasing humidity, indicating a higher mobility of smectite from interlayer hydration. Detailed characterization of the hydration state of smectite under original conditions is critical for understanding of clay-fluid interaction, the mechanical behavior during fault displacements, and fluid budgets at depth. We propose that humidity chamber experiments should be the new standard procedure to constrain swelling characteristics of natural and synthetic clay minerals. © 2013. American Geophysical Union. All Rights Reserved. 2013 English 15252027 10.1002/ggge.20077 Geochemistry, Geophysics, Geosystems 14 Blackwell Publishing Ltd 1039-1052 University of Michigan, Department of Earth and Environmental Sciences, 1100 N. University Ave, Ann Arbor, MI 48109-1005, United States; not available, 2-2475 West 3rd Avenue, Vancouver, BC V6K 1L9, Canada 4 Clay minerals; Ethylene; Ethylene glycol; Particle size analysis; Strike-slip faults; Tectonics, clay-hydration; Humidity chambers; NanTroSEIZE; SAFOD; Smectites, Hydration, active fault; adsorption; crystal structure; displacement; experimental mineralogy; humidity; hydration; San Andreas Fault; smectite; swelling; temperature effect; water; water content, Japan; Nankai Trough; Pacific Ocean; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-84878396633&doi=10.1002%2fggge.20077&partnerID=40&md5=350a56a8779b2f3033abd8bfd13827f2 cited By 18 A.M. Schleicher H. Hofmann article Hellevang20131287 This investigation involved three specimens: an altered felsic sample of impactite from the ICDP El'gygytgyn drill core D1c, and two reference volcanics from Iceland, namely a rhyolitic glass and a basaltic glass. The goal of this work was to better understand the alteration of impact melt and volcanic glass, and to apply the results to an investigation of alteration processes below the surface of Mars. Hydrothermal batch alteration experiments with the El'gygytgyn sample showed formation of various silica phases such as cristobalite, opal, and quartz. According to geochemical modeling, zeolites were also expected, but zeolite minerals already present in the impactite prior to the experiment may have masked possible experimental zeolite growth. Basaltic glass was altered to smectite, talc, and opal. The accompanying numerical modeling gave results that were similar or comparable to the laboratory experiments. Rhyolitic glass was kinetically more stable than basaltic glass, and showed only minor formation of calcite and feldspar during the 3-week experiment. The study showed that closed-system isochemical alteration of both siliceous and mafic glasses and melts results in the formation of smectites and zeolites. Therefore, to link alteration features on Mars to specific physical conditions, the exact identity of the mineral phases present in surface rocks must be known. Moreover, our simulations on closed-system isochemical alteration showed that the fraction of zeolites and silica formed relative to smectite depends on the source mineral altered. Therefore, fractions of these mineral groups present in the Martian soil may be used to better predict source rock characteristics. © The Meteoritical Society, 2013. 2013 English 10869379 10.1111/maps.12046 Meteoritics and Planetary Science 48 1287-1295 Department of Geosciences, University of Oslo, Oslo, N-0316, Norway; Department of Lithospheric Research, University of Vienna, Vienna, A-1090, Austria; Museum of Natural History, Vienna, A-1010, Austria 7 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84880175258&doi=10.1111%2fmaps.12046&partnerID=40&md5=5bdac3dace5f626c398669de644e241b cited By 9 H. Hellevang H. Dypvik E. Kalleson L. Pittarello C. Koeberl article Feng20136 The Continental Scientific Drilling Project at the Cretaceous-age Songliao Basin is a drilling initiative under the framework of the International Continental Scientific Drilling Program, to recover a nearly complete Cretaceous terrestrial sedimentary record in the Songliao Basin, northeastern China. The recovered cores will provide unique opportunities for the geosciences community to advance the understanding of climate change in the Cretaceous greenhouse world, and provide a documentation of geological events relevant to the carbon cycle during this time period.This drilling project will address significant geological questions, such as the identification of important stratigraphic boundaries and the marine-terrestrial correlations of stratigraphy, the reasons for the biotic response to the terrestrial environmental changes, the terrestrial response to the Cretaceous oceanic anoxic events, the formation of terrestrial petroleum source rocks, and the mechanisms for the Cretaceous magnetic Normal Superchron (CNS).In the first stage of this drilling project, the SKI drilling, rock cores of 2485.89. m in total length were recovered and the recovery ratio reached 96.46%. A series of drilling and coring technologies including regular, confined, directional, and sealed coring, were utilized to ensure a higher recovery ratio for the core, and will be described at the end of this paper. Well loggings were conducted right after coring. Core handling and storage were arranged in such a way that the scientific research was conducted on half of each core, whereas the other half of each core was preserved for long-term storage. The upcoming second stage, the SKII drilling, will combine with data from the existing SKI to provide complete high-resolution climate records of the terrestrial environment for the whole Cretaceous time period. © 2012 Elsevier B.V. 2013 English 00310182 10.1016/j.palaeo.2012.03.016 Palaeogeography, Palaeoclimatology, Palaeoecology 385 6-16 Institute of Exploration and Development of Daqing Oil field Company Ltd, Daqing 163712, China; State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing 100083, China; School of the Earth Science and Resources, China University of Geosciences, Beijing 100083, China; Department of Geological and Environmental Sciences, Stanford University, Stanford, CA, United States; Department of Lithospheric Research, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria; Natural History Museum, Burgring 7, A-1010 Vienna, Austria; Department of Geology, Miami University, Oxford, OH 45056, United States carbon cycle; climate variation; Cretaceous; drilling; geological record; proxy climate record; sedimentary basin; sedimentary sequence; source rock; stratigraphic boundary; stratigraphic correlation; timescale, China; Songliao Basin https://www.scopus.com/inward/record.uri?eid=2-s2.0-84879852230&doi=10.1016%2fj.palaeo.2012.03.016&partnerID=40&md5=c6ad4f7e4111268201e1e805dd95a38f cited By 46 Z. Feng C. Wang S. Graham C. Koeberl H. Dong Y. Huang Y. Gao conference Sun20135554 For reservoir rocks, P wave velocity dispersion may provide a potential link to rock physical properties. This requires continuous measurement of P wave velocity in a broad frequency band to determine the critical frequency of the attenuation mechanism. In this study, we measure P wave velocity dispersion continuously in sonic frequency range using broadband full-waveform multi-channel sonic logging data with the beam-forming and cross-correlation techniques. Results of the field data from 5L-38 Mallik gas hydrate research well have demonstrated the robustness of this method. The profile of P wave velocity dispersion matches very well with geological settings. The gas hydrate zones show very strong P wave velocity dispersion and a pronounced critical frequency around 15 kHz; weakly-laminated sediments also have strong P wave velocity dispersion with critical frequency lower than 5 kHz; P wave velocity dispersion in consolidated sediments is mild and gradual. In addition, the total magnitude of P wave velocity dispersion is positively correlated to resistivity and gas hydrate saturation. Therefore, continuous P wave velocity dispersion mapping can be a promising tool for reservoir characterization. Copyright © (2012) by the European Association of Geoscientists & Engineers All rights reserved. 2013 English 9781629937915 10.3997/2214-4609.20130043 75th European Association of Geoscientists and Engineers Conference and Exhibition 2013 Incorporating SPE EUROPEC 2013: Changing Frontiers European Association of Geoscientists and Engineers, EAGE 5554-5558 China University of Petroleum, Beijing, China; University of Toronto, Canada Acoustic logging; Acoustic wave velocity; Dispersion (waves); Gas hydrates; Hydration; Mapping; Wave propagation, Continuous mappings; Continuous measurements; Critical frequencies; Cross correlation techniques; Gas hydrate saturations; Laminated sediments; Reservoir characterization; Rock physical properties, Seismic waves https://www.scopus.com/inward/record.uri?eid=2-s2.0-84930433138&doi=10.3997%2f2214-4609.20130043&partnerID=40&md5=3136808d212f9650e6115316549132f6 cited By 2 L.F. Sun A. Campbell B. Milkereit article mei2013contrast 2013 Geoscience 27 925 4 XU Mei-gui ZHANG Shao-nan FU Mei-yan FAN Xiao-cong article Zhang2013547 Water samples from the Buha and Shaliu Rivers, located on the semi-arid northeastern Tibetan Plateau, were collected weekly over a one year period. The major ionic compositions of water samples were measured and the daily contents of suspended particulate material (SPM) were monitored in both rivers in order to investigate the influence of lithology, climate and physical erosion on seasonal silicate weathering. In the Shaliu River, weathering of trace amounts of calcite contributes more than 50% of the Ca2+ and HCO3- to the river water. Through high-resolution variations of Ca2+ concentrations and elemental ratios, the signal of carbonate precipitation is captured at the end of monsoon in this river. The measured physical erosion rate is only 8.7-16.0mm/kyr in this semi-arid region, which is 2-3 orders of magnitude lower than that in the Himalaya and nearby regions.In contrast with several orders of magnitude in seasonal variations of silicate weathering rates in both catchments, the distinct lithology between the catchments only leads to a 15 times difference of annual net CO2 consumption. The correlation analysis shows that seasonal silicate weathering is strongly dependent on water discharge in the semi-arid area. The most important observation is that, unrecognized by the previous studies, both physical erosion rate and air temperature exhibit two distinct trends with silicate weathering rates (and net CO2 consumption) during the years. The two trends might suggest that temperature plays a more important role on the CO2 consumption rate before the mid-monsoon under a condition of low water discharge than that after the monsoon with a high water discharge. During the period before the mid-monsoon, the relationship between temperature and silicate weathering rate exhibits higher activation energy than after the mid-monsoon, suggesting a greater dissolution of uneasily weatherable minerals from groundwater, frozen soil, and/or dust input. The relationship between erosion and weathering during the period before the mid-monsoon indicates a faster increase of silicate weathering rate, because freezing erosion produces large amount of high surface area minerals. © 2012 Elsevier Ltd. Article 2013 English 13679120 10.1016/j.jseaes.2012.11.004 Journal of Asian Earth Sciences 62 547 – 560 Buha River; China; Qinghai; Qinghai-Xizang Plateau; Shaliu River; carbon dioxide; climate effect; erosion; ionic composition; lithology; river water; seasonal variation; silicate; suspended particulate matter; weathering https://www.scopus.com/inward/record.uri?eid=2-s2.0-84872824962&doi=10.1016%2fj.jseaes.2012.11.004&partnerID=40&md5=f701a231b5636633d8b6b974197c542e Cited by: 18 Fei Zhang Zhangdong Jin Fuchun Li Jinmin Yu Jun Xiao article Sumita2013131 1 Corrections in Table 1 and Fig. 10 The attached Table 2 and Fig. 10 should replace the original Table 1 and Fig. 10. 1.1 Correction details in Table 2 1.2 Correction details in Fig. 10 2 Corrections in the text body The corrections in Table 2 necessitate the following slight changes in the text body (pages 22–29) 4.1.8. (page 23): Replace “Pantelleritic rhyolite” with “Comenditic rhyolite”. 4.1.20. (page 27): Replace “Trachyte” with “Comenditic rhyolite”. 4.1.21. (page 28): Replace “Pantelleritic rhyolite” with “Comenditic rhyolite”. 4.2.3. (page 28): Replace “Comenditic rhyolite” with “Comenditic rhyolite to trachyte”. 4.2.4. (page 28): Replace “Pantelleritic rhyolite” with “Comenditic rhyolite”. 4.2.6. (page 29): Replace “Trachyte” with “Comenditic rhyolite”. © 2013 Elsevier B.V. 2013 English 03770273 10.1016/j.jvolgeores.2013.01.008 Journal of Volcanology and Geothermal Research 253 Elsevier B.V. 131-133 GEOMAR Helmholtz Centre for Ocean Research Kiel, Wischhofstr. 1-3, Kiel, 24148, Germany https://www.scopus.com/inward/record.uri?eid=2-s2.0-84873403986&doi=10.1016%2fj.jvolgeores.2013.01.008&partnerID=40&md5=3b20f97cd3218a31dbf4f649982dbfba cited By 19 M. Sumita H.-U. Schmincke article asael2013coupled 2013 Chemical Geology 362 Elsevier 193--210 Dan Asael François LH Tissot Christopher T Reinhard Olivier Rouxel Nicolas Dauphas Timothy W Lyons Emmanuel Ponzevera Céline Liorzou Sandrine Chéron article Wang201317 As a paradigm of greenhouse climate in Earth's history, the Cretaceous provides significant rock records of global climate changes under conditions of greenhouse climate. The Songliao Basin, among the longest duration (85-90m.y.) of continental sedimentary basins, provides an excellent opportunity to recover a nearly complete Cretaceous terrestrial sedimentary record. Extensive lake deposits, ten-kilometers deep and covering an area of 260,000km2 of the Songliao Basin, provide unique, detailed records that can be tied to the global stratigraphic time scale, thereby improving our understanding of the continental paleoclimate and ecological system. The two coreholes at SKIs and SKIn sites were drilled into this basin and completed with a total length of 2485.89m of recovered core that spanned the complete middle-to-Upper Cretaceous strata in the basin. The unique geological setting of long-term continuous subsidence within the largest Cretaceous landmass in the world - makes the Cretaceous Songliao Basin of northeastern China an ideal place to study Cretaceous climate change on the continent. This paper reviews the literature on the paleogeography and paleoclimate of the northern East Asia and the Songliao Basin during the Cretaceous. Based on the climatologically sensitive deposits, oxygen isotope studies, and paleontology, the climate during the Cretaceous in the Songliao Basin was temperate and humid with relatively abundant rainfall. During the period, significant changes - four cooling, three warming, and three semiarid events - are generally consistent with the oxygen isotope data from East Asia, and the four cooling events, in Berriasian-Valanginian, Aptian-Albian, early Santonian, and Campanian-Maastrichtian, may be related to potential glaciations in Cretaceous. © 2012 Elsevier B.V. 2013 English 00310182 10.1016/j.palaeo.2012.01.030 Palaeogeography, Palaeoclimatology, Palaeoecology 385 17-30 State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing 100083, China; School of the Earth Science and Resources, China University of Geosciences, Beijing 100083, China; Institute of Exploration and Development of Daqing Oil field Company Ltd, Daqing 163712, China; Key Laboratory of Marine Hydrocarbon Resources and Environment Geology, Qingdao institute of marine geology, Qingdao 266071, China; School of Earth Sciences, Jilin University, Changchun 130061, China Albian; Aptian; Berriasian; borehole; cooling; geological record; glaciation; lacustrine deposit; literature review; oxygen isotope; paleoclimate; paleogeography; paleontology; sedimentary basin; subsidence; timescale; Valanginian, China; Songliao Basin https://www.scopus.com/inward/record.uri?eid=2-s2.0-84879859072&doi=10.1016%2fj.palaeo.2012.01.030&partnerID=40&md5=e276b842d3ba869ed509a065c82d70bc cited By 202 C. Wang Z. Feng L. Zhang Y. Huang K. Cao P. Wang B. Zhao article Eken2013911 The North Anatolia Fault Zone (NAFZ) is a transform zone 1600 km in length representing the plate boundary between the westward moving Anatolian Plate and stable Eurasia. Almost the entire fault zone has failed during the last century except for the Sea of Marmara section, which is located in direct vicinity to the city of Istanbul. In this study, we investigate the crustal anisotropy along the eastern Marmara section of the NAFZ based on shear-wave splitting. We measure seismic anisotropy parameters, namely, the fast polarization direction (PD) and time delay (TD), by analyzing local seismicity recorded at selected seismographs operated throughout the eastern Sea of Marmara region. Our shear-wave splitting (SWS) observations indicate a predominant northwest-southeast-oriented PD, which is subparallel to both the orientation of the regional SHmax in northwest Turkey and the local NAFZ strike along the Princes' Islands segment. Toward the south, at the Armutlu Peninsula, we find a different PD pattern reflecting local fault strikes, SHmax as well as strain asymmetry between different crustal blocks across the fault zone. Applying strict quality criteria enables us to identify robust, preferred fast PDs, which suggests that initially observed PD heterogeneities are sometimes caused by second-order effects in the data rather than by varying PDs. Comparing TD and hypocentral depth distribution, we find the depth extent of the anisotropy is confined to the uppermost 10-km depth of crust. We combine our SWS results with those from previous studies conducted along the San Andreas fault (SAF) and NAFZ in order to investigate the relation of angular deviations of the PDs from regional SHmax and local fault strikes with fault-zone distance. We find that fast PDs are mainly controlled by the local fault structure in close proximity to a fault zone (5 and 10 km) while they are controlled by crustal stress at off-fault locations (5 and 10 km). 2013 English 00371106 10.1785/0120120156 Bulletin of the Seismological Society of America 103 911-924 Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences, Potsdam D-14473, Germany; Bogazici University, Kandilli Observatory and Earthquake Research Institute, Istanbul, 34684, Turkey 2 A Angular deviations; Crustal anisotropy; Hypocentral depth; Northwestern Turkey; Polarization direction; Second order effect; Seismic anisotropy; Shear wave splitting, Shear waves; Strike-slip faults, Anisotropy, anisotropy; crustal structure; fault zone; North Anatolian Fault; plate boundary; San Andreas Fault; seismicity; wave splitting, Istanbul [Istanbul (PRV)]; Istanbul [Turkey]; Sea of Marmara; Turkey https://www.scopus.com/inward/record.uri?eid=2-s2.0-84875465771&doi=10.1785%2f0120120156&partnerID=40&md5=0fe27ce1d0c193ddd4efa8ca26f658ea cited By 23 T. Eken M. Bohnhoff F. Bulut B. Can M. Aktar article Recasens2013467 Article 2013 10.1080/0269249X.2013.842613 Diatom Research 28 467 – 472 4 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84888006966&doi=10.1080%2f0269249X.2013.842613&partnerID=40&md5=5af95b17f8bbdeab0a2c553b37803a09 Cited by: 8; All Open Access, Green Open Access Cristina Recasens Nora I. Maidana article Lu201354 Isoprenoid GDGTs (iGDGTs), along with their constituent biphytanyl moieties, are biomarkers for archaea. In order to obtain more information on identifying the carbon source and potential carbon assimilation pathway of archaea in surface sediments of Lake Qinghai and the surrounding soils, the stable carbon isotopic composition of iGDGT-derived biphytanes as well as its relationship with δ13C values of total organic carbon (TOC) and dissolved inorganic carbon (DIC) was investigated. The δ13C values of iGDGT-derived biphytanes ranged from -42.7‰ to -20.3‰. For example, the values for acyclic biphytanes (BP-0), the most abundant, varied from -25.0‰ to -22.1‰ in offshore sediments, -30.5‰ to -25.4‰ in surrounding soils and -42.7‰ to -32.0‰ in nearshore sediments. The wider variation than that of δ13CTOC (-26.9‰ to -25.1‰) in offshore sediments and that in surrounding soils indicated that δ13C values of BP-0 may be a sensitive indicator for examining the depositional environments between terrestrial and lacustrine systems. With average δ13C values of -23.6‰, crenarchaeol-derived biphytanes (BP-cren) in offshore sediments were enriched in 13C (ca. 3.6‰) relative to TOC. In addition, the carbon isotopic fractionation between BP-cren and DIC was -21.3‰, consistent with that reported for marine Thaumarchaeota. The enrichment in 13C relative to TOC and the similar carbon isotopic fractionation indicated that Thaumarchaeota in offshore sediments of Qinghai Lake are autotrophic. With average δ13C values of -29.2‰, BP-cren in surrounding soils was depleted by 0.9‰ to 12.8‰ in 13C relative to DIC. The quite large scatter in carbon isotopic fractionation between BP-cren and DIC indicated that the biomass of soil Thaumarchaeota originated from inorganic and organic carbon sources, suggesting a mixotrophic lifestyle. © 2013 Elsevier Ltd. Article 2013 English 01466380 10.1016/j.orggeochem.2013.04.012 Organic Geochemistry 60 54 – 61 China; Qinghai; Qinghai Lake; Isotopes; Lakes; Lipids; Microorganisms; Organic carbon; Sedimentology; Soils; Surficial sediments; Carbon assimilation; Carbon isotopic composition; Depositional environment; Dissolved inorganic carbon; Isotopic fractionations; Lacustrine systems; Sensitive indicator; Total Organic Carbon; biomarker; biomass; carbon isotope; depositional environment; eukaryote; isoprenoid; isotopic composition; lacustrine deposit; sediment pollution; soil pollution; Carbon https://www.scopus.com/inward/record.uri?eid=2-s2.0-84879352394&doi=10.1016%2fj.orggeochem.2013.04.012&partnerID=40&md5=5d5a89cb82b29a121935bd9a9fd41a31 Cited by: 5 Hongxuan Lu Weiguo Liu Huanye Wang Chuanlun L. Zhang article Wang201375 The BIT index represents the relative abundances of branched glycerol dialkyl glycerol tetraethers (bGDGTs) and the isoprenoid GDGT, crenarchaeol. While bGDGTs are produced mainly by soil (anaerobic) bacteria, crenarchaeol is known to be a biomarker for aerobic ammonia oxidation by chemolithoautotrophic Thaumarchaeota, particularly in the open ocean or lakes. Thus, the index in marine and lacustrine settings has been widely used as a proxy for soil input. Here, we have investigated GDGT distribution along two transects extending from the lake shore marsh to upland soils on the NE Qinghai-Tibetan plateau. The results show that soil water content (SWC) correlates positively with concentration of bGDGTs and negatively with concentration of crenarchaeol; consequently, there is a significant positive correlation between SWC and the BIT index. Our study highlights a new potential application of BIT as a humidity proxy in loess/soil and peat deposits. © 2013 Elsevier Ltd. Article 2013 English 01466380 10.1016/j.orggeochem.2013.03.011 Organic Geochemistry 59 75 – 81 China; Qinghai; Qinghai Lake; Qinghai-Xizang Plateau; Aerobic bacteria; Glycerol; Lipids; Soil moisture; Wetlands; Aerobic ammonia oxidations; Chemolithoautotrophic; Lake Qinghai; Positive correlations; Qinghai-Tibetan plateau; Relative abundance; Soil water content; Upland soil; bacterium; biomarker; humidity; isoprenoid; loess; marsh; open ocean; paleolimnology; peat soil; relative abundance; shore (nonmarine); soil water; upland region; water content; Lakes https://www.scopus.com/inward/record.uri?eid=2-s2.0-84877114687&doi=10.1016%2fj.orggeochem.2013.03.011&partnerID=40&md5=48639a55cef51983f2153a47b9e533cb Cited by: 35 Huanye Wang Weiguo Liu Chuanlun L. Zhang Zhonghui Liu Yuxin He article Verschuren201372 2013 English 18168957 10.2204/iodp.sd.15.09.2013 Scientific Drilling 72-76 Ghent University, Limnology Unit, K.L., Ledeganckstraat 35, B-9000 Ghent, Belgium; University of Nairobi, Department of Geology, Chiromo Campus, P.O. Box 30197, Nairobi 00100, Kenya; Palynology and Palaeobotany Section, National Museums of Kenya, P.O. Box 40658, Nairobi 00100, Kenya; Office of the Prime Minister, P.O. Box 74434, Nairobi 00200, Kenya 15 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84877833251&doi=10.2204%2fiodp.sd.15.09.2013&partnerID=40&md5=7af28582042289c69cfb02ee73e188df cited By 8 D. Verschuren D.O. Olagod S.M. Rucina P.O. Odhengo article Fridleifsson201373 A summary workshop report describing the progress made so far by the Iceland Deep Drilling Project (IDDP) is presented below. The report provides recommendations concerning technical aspects related to deep drilling, and invites international participation in both the engineering and the scientific activities of the next phase of the IDDP. No issues were identified at the workshop that should rule out attempting the drilling, sampling and testing of the proposed IDDP-2 well. Although technically challenging, the consensus of the workshop was that the drilling of such a hot deep well, and producing potentially hostile fluids, is possible but requires careful contingency planning. The future well will be explored for supercritical fluid and/or superheated steam beneath the current production zone of the Reykjanes geothermal field in SW Iceland. This deep borehole will provide the first opportunity worldwide to directly investigate the root zone of a magma-hydrothermal system which is likely to be similar to those beneath the black smokers on the worldencircling mid-ocean rift systems. © Author(s) 2013. 2013 English 18168957 10.5194/sd-16-73-2013 Scientific Drilling 73-79 HS Orka hf., Brekkustígur 36, 260 Reykjanesbær, Iceland; Department of Earth Sciences, University of California, Riverside, CA 92521, United States; GNS Science, Wairakei Research Centre, Karetoto Road, Taupo, New Zealand 16 Contingency planning; Current production; Deep boreholes; Deep drilling; Iceland deep drilling projects; Scientific activity; Superheated steam; Technical aspects, Drilling fluids; Effluent treatment; Geothermal fields; Supercritical fluids, Boring https://www.scopus.com/inward/record.uri?eid=2-s2.0-84892840331&doi=10.5194%2fsd-16-73-2013&partnerID=40&md5=0f5f4a1c8694c8a03d16a2a3d06724c7 cited By 9 G.Ó. Fridleifsson W.A. Elders G. Bignall article Raschke20131143 In 2008/2009, the International Continental Scientific Drilling Program (ICDP) obtained drill cores from the El'gygytgyn impact structure located on the Chukotka Peninsula (Russia). These cores provide the most complete geological section ever obtained from an impact structure in siliceous volcanic rock. The lithostratigraphy comprises a thick sequence of lacustrine sediments overlying impact breccias and deformed target rock. The interval from 316 m (below lake floor-blf) to the end of the core at 517 m depth can be subdivided into four lithological sequences. At 316 m depth, the first mesoscopic clasts of shocked target rock occur in lacustrine sediments. The growing abundance of target rock clasts with increasing depth and corresponding decrease of lacustrine sediment components indicate the extent of this transition zone to 328 m depth. It constitutes a zone of mixed reworked impact breccia and lacustrine sediments. Volcanic clasts in this reworked suevite section show all stages of shock metamorphism, up to melting. The underlying unit (328-390 m depth) represents a suevite package, a polymict impact breccia, with considerable evidence of shock deformation in a wide variety of volcanic clasts. This includes fragments with quartz that exhibit planar fractures and planar deformation features (PDF). In addition, at three depths, several centimeter-sized clasts with shatter cones were detected. Due to microanalytical identification of relatively rare, microscopic impact melt particles in the matrix of this breccia, this material can be confidently labeled a suevite. Also in this sequence, three unshocked, <1 m thick intersections of volcanic blocks occur at 333.83, 351.52, and 383.00 m depths. The upper bedrock unit begins at 390.74 m depth, has a thickness of 30.15 m, and represents a sequence of different volcanic rocks-an upper part with basaltic composition from 390.74 to 391.79 m depth overlying a lower, rhyodacitic part from 391.79 to 420.27 m depth. This (parautochthonous) basement unit is only very weakly affected by the impact: only one shocked quartz grain with two sets of PDF was recorded at 391.33 m depth. The lower bedrock unit (420.89-517.09 m depth [end of core]) is a brittly deformed, rather homogeneous welded ignimbrite that in part can be considered a cataclasite. The top three meters of this section are sheared, which could represent pre-impact tectonic deformation. A 54 cm thick injection of polymict impact breccia occurs at 471.42-471.96 m depth. © The Meteoritical Society, 2013. 2013 English 10869379 10.1111/maps.12072 Meteoritics and Planetary Science 48 1143-1159 Museum für Naturkunde Berlin - Leibniz Institute for Evolution and Biodiversity Research, Invalidenstrasse 43, Berlin, 10115, Germany; Humboldt Universität zu Berlin, Unter den Linden 6, Berlin, 10099, Germany; Department of Lithospheric Research, Center for Earth Sciences, University of Vienna, Althanstrasse 14, Vienna, 1090, Austria; Natural History Museum Vienna, Burgring 7, Vienna, 1010, Austria 7 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84880173001&doi=10.1111%2fmaps.12072&partnerID=40&md5=32c0826bf9df1a3596b5586d9e1f3ff0 cited By 21 U. Raschke W.U. Reimold P.T. Zaag L. Pittarello C. Koeberl incollection lepland20135 2013 Reading the Archive of Earth’s Oxygenation Springer 493--502 Aivo Lepland Melanie Mesli Ronald Conze Karl Fabian Anthony E Fallick LR Kump incollection melezhik20136 2013 Reading the Archive of Earth’s Oxygenation Springer 505--590 Victor A Melezhik Anthony R Prave Aivo Lepland Eero J Hanski Alexander E Romashkin Dmitry V Rychanchik Zhen-Yu Luo Evgenii V Sharkov Maria M Bogina Alex T Brasier others article kump20137 2013 Reading the Archive of Earth’s Oxygenation: Volume 3: Global Events and the Fennoscandian Arctic Russia-Drilling Early Earth Project Springer 1457--1514 Lee R Kump Anton B Kuznetsov Igor M Gorokhov Victor A Melezhik Juraj Farkaš Ramananda Chakrabarti Stein B Jacobsen Christopher T Reinhard Timothy W Lyons Olivier Rouxel others article cp-9-1559-2013 Rock magnetic, biochemical and inorganic records of the sediment cores PG1351 and Lz1024 from Lake El'gygytgyn, Chukotka peninsula, Far East Russian Arctic, were subject to a hierarchical agglomerative cluster analysis in order to refine and extend the pattern of climate modes as defined by Melles et al. (2007). Cluster analysis of the data obtained from both cores yielded similar results, differentiating clearly between the four climate modes warm, peak warm, cold and dry, and cold and moist. In addition, two transitional phases were identified, representing the early stages of a cold phase and slightly colder conditions during a warm phase. The statistical approach can thus be used to resolve gradual changes in the sedimentary units as an indicator of available oxygen in the hypolimnion in greater detail. Based upon cluster analyses on core Lz1024, the published succession of climate modes in core PG1351, covering the last 250 ka, was modified and extended back to 350 ka. Comparison to the marine oxygen isotope (δ18O) stack LR04 (Lisiecki and Raymo, 2005) and the summer insolation at 67.5 °N, with the extended Lake El'gygytgyn parameter records of magnetic susceptibility (κLF), total organic carbon content (TOC) and the chemical index of alteration (CIA; Minyuk et al., 2007), revealed that all stages back to marine isotope stage (MIS) 10 and most of the substages are clearly reflected in the pattern derived from the cluster analysis. © Author(s) 2013. 2013 English 18149324 10.5194/cp-9-1559-2013 Climate of the Past 9 1559-1569 Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences, Section 5.2 - Paleoclimate and Landscape Evolution, 14473 Potsdam, Germany; North-East Interdisciplinary Science Research Institute, FEB RAS, 685000 Magadan, Russian Federation; Institute of Geology and Mineralogy, University of Cologne, 50674 Cologne, Germany; Climate Impacts Research Centre (CIRC), Umeå University, 98107 Abisko, Sweden 4 climate change; climate modeling; cluster analysis; hierarchical system; oxygen isotope; sediment core; statistical analysis, Arctic Ocean; Chukchi; Elgygytgyn Lake; Far East; Russian Federation https://cp.copernicus.org/articles/9/1559/2013/ cited By 10 U. Frank N. R. Nowaczyk P. Minyuk H. Vogel P. Rosen M. Melles article Holland2013243 Arctic paleoenvironmental archives serve as sensitive recorders of past climate change. Lake El'gygytgyn (Far East Russian Arctic) is a high-latitude crater impact lake that contains a continuous sediment record influenced by neither glaciation nor glacial erosion since the time of impact 3.58 Ma ago. Prior research on sediments collected from Lake El'gygytgyn suggest times of permanent ice cover and anoxia corresponding to global glacial intervals, during which the sediments are laminated and are characterized by the co-occurrence of high total organic carbon, microscopic magnetite grains that show etching and dissolution, and negative excursions in bulk sediment organic matter carbon isotope (δ13C) values. Here we investigate the abundance and carbon isotopic composition of lipid biomarkers recovered from Lake El'gygytgyn sediments spanning marine isotope stages 1-3 to identify key sources of organic matter (OM) to lake sediments, to establish which OM sources drive the negative δ13C excursion exhibited by bulk sediment OM, and to explore if there are molecular and isotopic signatures of anoxia in the lake during glaciation. We find that during marine isotope stages 1-3, direct evidence for water column anoxia is lacking. A ∼4&amp;permil; negative excursion in bulk sediment δ13C values during the Local Last Glacial Maximum (LLGM) is accompanied by more protracted, higher magnitude negative excursions in n-alkanoic acid and n-alkanol δ13C values that begin 20 kyr in advance of the LLGM. In contrast, n-alkanes and the C30 n-alkanoic acid do not exhibit a negative δ13C excursion at this time. Our results indicate that the C24, C26 and C28 n-alkanoic acids do not derive entirely from terrestrial OM sources, while the C30 n-alkanoic acid at Lake El'gygytgyn is a robust indicator of terrestrial OM contributions. Overall, our results strongly support the presence of a nutrient-poor water column, which is mostly isolated from atmospheric carbon dioxide during glaciation at Lake El'gygytgyn. © 2013 Author(s). 2013 English 18149324 10.5194/cp-9-243-2013 Climate of the Past 9 243-260 Department of Geosciences, University of Massachusetts Amherst, Amherst, MA 01003, United States 1 anoxic conditions; biomarker; carbon cycle; carbon isotope; climate change; glaciation; isotopic analysis; isotopic composition; lacustrine deposit; Last Glacial Maximum; marine environment; organic carbon; organic matter; paleoenvironment; sediment chemistry; water column, Chukchi; Elgygytgyn Lake; Russian Federation https://www.scopus.com/inward/record.uri?eid=2-s2.0-84873889475&doi=10.5194%2fcp-9-243-2013&partnerID=40&md5=ed2d055f981603bd866c60b127cae90b cited By 15 A.R. Holland S.T. Petsch I.S. Castañeda K.M. Wilkie S.J. Burns J. Brigham-Grette article cp-9-243-2013 2013 10.5194/cp-9-243-2013 Climate of the Past 9 243-260 1 https://cp.copernicus.org/articles/9/243/2013/ A. R. Holland S. T. Petsch I. S. Castaneda K. M. Wilkie S. J. Burns J. Brigham-Grette article Song2013137 The abundance and composition of total organic carbon, aliphatic and aromatic hydrocarbons including biomarkers, and the δ13C composition of total organic matter and individual compounds in core samples of the Nenjiang Formation from the SK-1 borehole of the Songliao Basin provide information on the paleoenvironmental conditions of lacustrine sediments formed during the Upper Cretaceous. The distribution of n-alkanes, and their δ13C composition, and 4-methylsteranes and dinosteranes in the first member of the Nenjiang Formation (K2n1) indicate that the organic matter largely originated from algal organisms and is dominated by types I and II kerogen. The occurrence of gammacerane, aryl isoprenoids isorenieratane and low pristane/phytane and diasterane/sterane ratios further suggest a salinity stratified water column associated with anoxic bottom waters, as well as possible photic zone oxygen depletion conditions during major source rock deposition of the K2n1. The organic geochemical data also indicate significantly different depositional environments for the second member of the Nenjiang Formation (K2n2) sediments, which are interpreted to have been deposited under a uniform salinity (non-stratified) oxic water column. Consequently, although the organic matter in the K2n2 sediments was largely derived from algal and bacterial sources, the kerogen types are dominantly IIb and III due to the oxidative degradation of organic matter, combined with a gradual increase in land-plant input. Furthermore, the occurrence and shift of two saw-toothed distribution patterns of the δ13C composition of C29 to C33 n-alkanes, with "W" and "M" patterns being isotopically heavy odd- and even-numbered alkanes, respectively, is suggestive of organic input shift or an unknown mechanism of carbon uptake or isotopic fractionation. In particular, the heavy even carbon numbered high molecular weight n-alkanes is rare and needs further investigation. © 2012 Elsevier B.V. 2013 English 00310182 10.1016/j.palaeo.2012.12.007 Palaeogeography, Palaeoclimatology, Palaeoecology 385 137-151 State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; Department of Earth and Planetary Sciences, Macquarie University, NSW 2109, Australia; Exploration and Development Research Institute of Daqing Oil Field Company, Daqing 163712, China; Graduate School of Chinese Academy of Sciences, Beijing 100039, China biomarker; carbon isotope; core analysis; Cretaceous; depositional environment; isotopic fractionation; kerogen; lacustrine deposit; lacustrine environment; organic matter; paleoenvironment; source rock; water column, China; Nen Basin; Songliao Basin, algae; Bacteria (microorganisms); Embryophyta https://www.scopus.com/inward/record.uri?eid=2-s2.0-84879890666&doi=10.1016%2fj.palaeo.2012.12.007&partnerID=40&md5=7c3f3515690c3fd879f740fe148641e1 cited By 55 Z. Song Y. Qin S.C. George L. Wang J. Guo Z. Feng article Francke2013481 Article 2013 10.5194/cp-9-481-2013 Climate of the Past 9 481 – 498 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84880895188&doi=10.5194%2fcp-9-481-2013&partnerID=40&md5=33453b28dcbf58ff76454f0cbb0ffc6a Cited by: 79; All Open Access, Gold Open Access, Green Open Access A. Francke B. Wagner M.J. Leng J. Rethemeyer article Tarasov20132759 The recent and fossil pollen data obtained under the frame of the multi-disciplinary international El'gygytgyn Drilling Project represent a unique archive, which allows the testing of a range of pollen-based reconstruction approaches and the deciphering of changes in the regional vegetation and climate. In the current study we provide details of the biome reconstruction method applied to the late Pliocene and Quaternary pollen records from Lake El'gygytgyn. All terrestrial pollen taxa identified in the spectra from Lake El'gygytgyn were assigned to major vegetation types (biomes), which today occur near the lake and in the broader region of eastern and northern Asia and, thus, could be potentially present in this region during the past. When applied to the pollen spectra from the middle Pleistocene to present, the method suggests (1) a predominance of tundra during the Holocene, (2) a short interval during the marine isotope stage (MIS) 5.5 interglacial distinguished by cold deciduous forest, and (3) long phases of taiga dominance during MIS 31 and, particularly, MIS 11.3. These two latter interglacials seem to be some of the longest and warmest intervals in the study region within the past million years. During the late Pliocene-early Pleistocene interval (i.e., ∼3.562-2.200 Ma), there is good correspondence between the millennial-scale vegetation changes documented in the Lake El'gygytgyn record and the alternation of cold and warm marine isotope stages, which reflect changes in the global ice volume and sea level. The biome reconstruction demonstrates changes in the regional vegetation from generally warmer/wetter environments of the earlier (i.e., Pliocene) interval towards colder/drier environments of the Pleistocene. The reconstruction indicates that the taxon-rich cool mixed and cool conifer forest biomes are mostly characteristic of the time prior to MIS G16, whereas the tundra biome becomes a prominent feature starting from MIS G6. These results consistently indicate that the study region supported significant tree populations during most of the interval prior to ∼2.730 Ma. The cold- and drought-tolerant steppe biome first appears in the reconstruction ∼3.298 Ma during the tundra-dominated MIS M2, whereas the tundra biome initially occurs between ∼3.379 and ∼3.378 Ma within MIS MG4. Prior to ∼2.800 Ma, several other cold stages during this generally warm Pliocene interval were characterized by the tundra biome. © Author(s) 2013. CC Attribution 3.0 License. 2013 English 18149324 10.5194/cp-9-2759-2013 Climate of the Past 9 2759-2775 Institute of Geological Sciences, Palaeontology Section, Free University Berlin, Malteserstr. 74andndash;100, Haus D, 12249 Berlin, Germany; Institute of Geology and Mineralogy, University of Cologne, Zülpicher Str. 49a, 50674 Cologne, Germany; Earth and Space Sciences and Quaternary Research Center, University of Washington, Seattle, WA 98195-1310, United States; Northeast Interdisciplinary Scientific Research Institute, Far East Branch, Russian Academy of Sciences, 16 Portovaya St., Magadan, 685000, Russian Federation; Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences, Section 5.2 Andndash; Climate Dynamics and Landscape Evolution, Telegrafenberg, 14473 Potsdam, Germany; Department of Geology, Lund University, Sölvegatan 12, 22362 Lund, Sweden; Department of Geosciences, University of Massachusetts, 611 North Pleasant St., Amherst, MA 01003, United States 6 biome; climate variation; cold tolerance; deciduous forest; drought stress; fossil assemblage; Holocene; interglacial; palynology; Pliocene; reconstruction; vegetation history, Arctic; Chukchi; Elgygytgyn Lake; Russian Far East; Russian Federation https://www.scopus.com/inward/record.uri?eid=2-s2.0-84890463524&doi=10.5194%2fcp-9-2759-2013&partnerID=40&md5=558958825708fd70d9cf9ab4b0111cb2 cited By 66 P.E. Tarasov A.A. Andreev P.M. Anderson A.V. Lozhkin C. Leipe E. Haltia N.R. Nowaczyk V. Wennrich J. Brigham-Grette M. Melles article Nuttin2013109 The ~100m-long Laguna Potrok Aike sediment sequence yielded a record spanning the Last Glacial period to the Holocene. This paper presents and discusses two aspects of the mineralogy of the lake. The first aspect is based on a semi-quantitative X-ray diffraction analysis of bulk and clay mineralogical assemblages. Minor mineralogical changes are observed throughout the glacial section suggesting relatively uniform sediment sources. The transition into the Holocene is characterized by increasing fluxes of endogenic calcite thought to relate to lower lake levels. The second aspect is based on analysis of uranium-series disequilibria in diagenetic vivianite from the glacial section. U-series ages were expected to yield minimum ages for the host-sediment. Unfortunately, very little authigenic U is present in vivianite grains. The low primary productivity of the lake and thus low organic carbon fluxes might have prevented the development of strong redox gradients at the water-sediment interface and thus reduced diagenetic U-uptake into the sediment. One vivianite sample, at a 56.9m composite depth, yielded enough authigenic uranium to calculate a 230Th-age of 29.4±5.9ka (±2σ). This age is younger than the one indicated by the radiocarbon chronology. It is thus concluded that a relatively late diagenetic evolution of the U-Th system characterizes the recovered vivianite minerals. The authigenic U displays a very high excess in 234U (over 238U) with an activity ratio of 4.58±0.58 (±2σ). It suggests that it originates from the transfer of highly fractionated U from surrounding detrital minerals through very low U-content pore waters. © 2012 Elsevier Ltd. Article 2013 10.1016/j.quascirev.2012.09.027 Quaternary Science Reviews 71 109 – 118 Argentina; Laguna Potrok Aike; Santa Cruz [Argentina]; Clay; Crystallography; Glacial geology; Lakes; Mineralogy; Sedimentology; Sediments; Uranium; X ray diffraction analysis; Argentina; ICDP-PASADO; Late quaternary; Paleoclimates; Vivianite; XRD; authigenesis; calcite; carbon flux; geochronology; Holocene; Last Glacial Maximum; mineral; mineralogy; primary production; radiocarbon dating; redox potential; vivianite; X-ray diffraction; Phosphate minerals https://www.scopus.com/inward/record.uri?eid=2-s2.0-84878950591&doi=10.1016%2fj.quascirev.2012.09.027&partnerID=40&md5=500466f10693c10f031fe0c92a06df87 Cited by: 17 L. Nuttin P. Francus M. Preda B. Ghaleb C. Hillaire-Marcel article cp-9-2759-2013 2013 10.5194/cp-9-2759-2013 Climate of the Past 9 2759-2775 6 https://cp.copernicus.org/articles/9/2759/2013/ P. E. Tarasov A. A. Andreev P. M. Anderson A. V. Lozhkin C. Leipe E. Haltia N. R. Nowaczyk V. Wennrich J. Brigham-Grette M. Melles inproceedings rozanov2013unique 2013 SP MAIK Nauka/Interperiodica Doklady Biological Sciences 449 96--98 1 A Yu Rozanov MM Astafieva article Shanahan201347 The continuous 300-m long drill cores obtained from Lake Bosumtwi, Ghana represent one of the longest, continuous lacustrine sequences obtained from an extant lake, and contain an unprecedented record of late Quaternary climate change in West Africa. However, one of the main challenges associated with generating long paleoclimate time series from terrestrial records such as this is the development of accurate age-depth relationships because unlike marine records, lacustrine sequences cannot be tuned to global ice volume records via δ18O stratigraphy. The Lake Bosumtwi record thus offers an excellent case study for examining the potential and the challenges associated with different geochronological techniques in lacustrine systems. In the present study, we use a combination of radiocarbon, optically stimulated luminescence and U-series dating and paleomagnetic excursions to generate a chronology for the upper ca. 150 ka of sedimentation at Lake Bosumtwi and employ a Bayesian approach to generate a continuous age-depth relationship. The resultant chronology is then used to test the effectiveness of tuning of an environmental magnetic proxy for dust against a well-dated record of high latitude dust. Our approach highlights the advantages of using multiple dating approaches, and the dangers of relying on too few age constraints when dating long sedimentary sequences. However, the excellent agreement between the different approaches over most of the record suggest that well-constrained age-depth models for long sedimentary sequences can be produced using this combination of approaches. Furthermore, our data provide support for extending the chronology beyond the limit of radiocarbon, U-series and OSL in the future using paleomagnetic excursions/reversals and tuning against well-dated high latitude paleoclimate records. © 2012 Elsevier B.V. Article 2013 English 18711014 10.1016/j.quageo.2012.12.001 Quaternary Geochronology 15 47 – 60 Ashanti; Ghana; Lake Bosumtwi; Bayesian analysis; chronology; climate variation; lacustrine deposit; paleoclimate; paleomagnetism; radiocarbon dating; sedimentary sequence; sedimentation; time series; uranium series dating https://www.scopus.com/inward/record.uri?eid=2-s2.0-84875259409&doi=10.1016%2fj.quageo.2012.12.001&partnerID=40&md5=9106825168f72506e979d68b0be4cb9f Cited by: 29 Timothy M. Shanahan John A. Peck Nicholas McKay Clifford W. Heil John King Steven L. Forman Dirk L. Hoffmann David A. Richards Jonathan T. Overpeck Christopher Scholz article Cunningham2013679 To date, terrestrial archives of long-term climatic change within the Arctic have widely been restricted to ice cores from Greenland and, more recently, sediments from Lake El'gygytgyn in northeast Arctic Russia. Sediments from this lake contain a paleoclimate record of glacialinterglacial cycles during the last three million years. Lowresolution studies at this lake have suggested that changes observed during Transition IV (the transition from marine isotope stage (MIS) 10 to MIS 9) are of greater amplitude than any observed since. In this study, geochemical parameters are used to infer past climatic conditions thus providing the first high-resolution analyses of Transition IV from a terrestrial Arctic setting. These results demonstrate that a significant shift in climate was subsequently followed by a rapid increase in biogenic silica (BSi) production. Following this sharp increase, bioproductivity remained high, but variable, for over a thousand years. This study reveals differences in the timing and magnitude of change within the ratio of silica to titanium (Si/Ti) and BSi records that would not be apparent in lower resolution studies. This has significant implications for the increasingly common use of Si/Ti data as an alternative to traditional BSi measurements. © Author(s) 2013. 2013 English 18149324 10.5194/cp-9-679-2013 Climate of the Past 9 679-686 Climate Impacts Research Centre (CIRC), Umeå University, 98107 Abisko, Sweden; University of Cologne, Institute of Geology and Mineralogy, Zuelpicher Str. 49a, 0674 Cologne, Germany; University of Bern, Institute of Geological Sciences and Oeschger Centre for Climate Change Research, Baltzerstr. 1 + 3, 3012 Bern, Switzerland; GeoForschungsZentrum Potsdam, Section 3.3, Telegrafenberg, 14473 Potsdam, Germany; Department of Geography and Geosciences, University of St Andrews, St Andrews, Fife KY16 9AL, United Kingdom 2 climate change; data acquisition; geochemical cycle; ice core; lacustrine environment; marine isotope stage; paleoclimate; record; silica; titanium, Arctic; Chukchi; Elgygytgyn Lake; Greenland; Russian Federation https://www.scopus.com/inward/record.uri?eid=2-s2.0-84881130929&doi=10.5194%2fcp-9-679-2013&partnerID=40&md5=ff6b9131fdf3ca151d581b79c51fc16d cited By 9 L. Cunningham H. Vogel V. Wennrich O. Juschus N. Nowaczyk P. Rosen article cp-9-679-2013 2013 10.5194/cp-9-679-2013 Climate of the Past 9 679-686 2 https://cp.copernicus.org/articles/9/679/2013/ L. Cunningham H. Vogel V. Wennrich O. Juschus N. Nowaczyk P. Rosen article Bohnhoff2013 Over the last century the North Anatolian Fault Zone in Turkey has produced a remarkable sequence of large earthquakes. These events have now left an earthquake gap south of Istanbul and beneath the Marmara Sea, a gap that has not been filled for 250 years. Here we investigate the nature of the eastern end of this gap using microearthquakes recorded by seismographs primarily on the Princes Islands offshore Istanbul. This segment lies at the western terminus of the 1999 Mw7.4 Izmit earthquake. Starting from there, we identify a 30-km-long fault patch that is entirely aseismic down to a depth of 10 km. Our evidence indicates that this patch is locked and is therefore a potential nucleation point for another Marmara segment earthquake - a potential that has significant natural hazards implications for the roughly 13 million Istanbul residents immediately to its north. © 2013 Macmillan Publishers Limited. All rights reserved. 2013 English 20411723 10.1038/ncomms2999 Nature Communications 4 Helmholtz-Centre Potsdam German Centre for Geosciences GFZ, Telegrafenberg, 14473 Potsdam, Germany; Department of Earth Sciences, Freie Universitat Berlin, Malteser Strasse 74-100, 12249 Berlin, Germany; Institute of Earth Science and Engineering, University of Auckland, Auckland, New Zealand; Kandilli Observatory and Earthquake Research Institute, Bogazici University, 34342 Bebek, Cengelköy, Istanbul, Turkey active fault; earthquake event; fault zone; Kocaeli earthquake 1999; microearthquake; nucleation; seismic hazard; seismograph, article; biological accident; correlation analysis; earthquake; Turkey (republic), Earthquakes; Geography; Humans; Islands; Oceans and Seas; Turkey, Istanbul [Turkey]; Sea of Marmara; Turkey https://www.scopus.com/inward/record.uri?eid=2-s2.0-84879664833&doi=10.1038%2fncomms2999&partnerID=40&md5=2f690a02f732647cb1810f8df6b91ffd cited By 94 M. Bohnhoff F. Bulut G. Dresen P.E. Malin T. Eken M. Aktar article Wang201369 The ratio of archaeol to caldarchaeol (the ACE index) has been proposed recently as an index for paleosalinity reconstruction and is based principally on archaeal core lipids (CLs) from coastal salt pans (Turich, C., Freeman, K.H., 2011. Archaeal lipids record paleosalinity in hypersaline systems. Organic Geochemistry 42, 1147-1157). We have examined possible relationships between salinity and ACE in both CLs and intact polar lipids (IPLs) from suspended particulate matter (SPM) and surface sediments of lakes and surrounding soils on the northeastern Qinghai-Tibetan Plateau. Our results showed that ACE values were positively correlated with salinity in all samples; however, CL ACE values were systematically higher than IPL ACE values, probably due to different degradation kinetics of intact polar (IP) archaeol and IP caldarchaeol. On the other hand, surface sediment ACE values from both CLs and IPLs were lower than SPM ACE values, probably due to enhanced production of caldarchaeol relative to archaeol in the sediment. Our results demonstrate that the ACE proxy reflects changes in salinity in diverse environments on the Qinghai-Tibetan Plateau, which is promising for paleosalinity reconstruction; however, caution should be used when applying the salinity proxy before we have a better understanding of degradation kinetics of archaeal IPLs and in situ production of caldarchaeol and archaeol in sediments. © 2012 Elsevier Ltd. Article 2013 English 01466380 10.1016/j.orggeochem.2012.09.011 Organic Geochemistry 54 69 – 77 China; Qinghai-Xizang Plateau; Archaea; Degradation; Lakes; Lipids; Sedimentology; Surficial sediments; Archaeal; Degradation kinetics; Hypersaline; In-situ production; Northeastern Qinghai-Tibetan Plateau; Organic geochemistry; Polar lipids; Qinghai-Tibetan plateau; Surface sediments; Surrounding soils; Suspended particulate matters; correlation; dehydration; in situ measurement; in situ test; lake water; lipid; organic geochemistry; paleosalinity; saline lake; sampling; upland region; Salinity measurement https://www.scopus.com/inward/record.uri?eid=2-s2.0-84868676037&doi=10.1016%2fj.orggeochem.2012.09.011&partnerID=40&md5=33ed6ac8cd50fa49a1c2985794e57d86 Cited by: 33 Huanye Wang Weiguo Liu Chuanlun L. Zhang Hongchen Jiang Hailiang Dong Hongxuan Lu Jinxiang Wang article Wu201355 The first complete Early Turonian-Early Campanian lacustrine succession has been recovered from the SK-I south (SK-Is) borehole in the Songliao Basin (SLB), northeastern China. We conducted a detailed cyclostratigraphic study of natural gamma-ray (GR) log, thorium (Th) log, and magnetic susceptibility (MS) data from this core. Spectral analysis of the upper Quantou Formation (K2q3+4), Qingshankou Formation (K2qn), Yaojia Formation (K2y), and lower Nenjiang Formation (K2n1+2) reveals a hierarchy of meter- to decameter-scale cycling in the data. The wavelength ratios of the cycles in these stratigraphic units are ~20:5:2:1, corresponding with those of Milankovitch cycle periods of 405kyr (long eccentricity):100kyr (short eccentricity):37kyr (obliquity):20kyr (precession), indicating astronomical control on sedimentation. An astronomical time scale (ATS) was established by tuning interpreted 405kyr cycles to a 405kyr orbital eccentricity target curve, and to four SIMS U-Pb zircon radioisotope ages. This 'absolute' ATS provides precise numerical ages for stratigraphic boundaries, biozones, geological and geophysical events, and serves as a basis for correlation of strata and events between marine and terrestrial systems. The ages of the C33r/C34n geomagnetic polarity boundary in K2n2 and three short reversal events in K2y are estimated as 83.633Ma, 84.819-84.862Ma, 84.982-85.092Ma and 85.240-85.629Ma, respectively. Long-period amplitude modulations in the obliquity and eccentricity bands of the 405-kyr-tuned GR-Th series provide strong evidence that long-period orbital forcing influenced climate change and depositional processes in the SLB. The extracted amplitude modulations provide evidence that the orbits of Earth and Mars were not in secular resonance, and were undergoing chaotic interactions during this time, although the modulations do not match those of recent astronomical models. © 2012 Elsevier B.V. 2013 English 00310182 10.1016/j.palaeo.2012.09.004 Palaeogeography, Palaeoclimatology, Palaeoecology 385 55-70 State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing 100083, China; School of Ocean Sciences, China University of Geosciences (Beijing), Beijing 100083, China; Department of Geoscience, University of Nevada, Las Vegas, NV 89154, United States; Department of Earth and Planetary Sciences, Johns Hopkins University, Baltimore, MD 21218, United States amplitude; astronomy; astrophysics; borehole; Campanian; cyclostratigraphy; eccentricity; geomagnetic field; lacustrine environment; magnetic susceptibility; Milankovitch cycle; orbital forcing; paleoenvironment; secular variation; solar system; spectral analysis; stratigraphic correlation; timescale; Turonian; uranium-lead dating, China; Nen Basin; Songliao Basin https://www.scopus.com/inward/record.uri?eid=2-s2.0-84879876484&doi=10.1016%2fj.palaeo.2012.09.004&partnerID=40&md5=b6062b1bb998a69c777c13ab8b421017 cited By 122 H. Wu S. Zhang G. Jiang L. Hinnov T. Yang H. Li X. Wan C. Wang article Lorenschat201342 Understanding the ecology of bioindicators such as ostracods is essential in order to reconstruct past environmental and climate change from analysis of fossil assemblages preserved in lake sediment cores. Knowledge of the ecology of ancient Lake Ohrid's ostracod fauna is very limited and open to debate. In advance of the Ohrid ICDP-Drilling project, which has potential to generate high-resolution long-term paleoenvironmental data of global importance in paleoclimate research, we sampled Lake Ohrid and a wide range of habitat types in its surroundings to assess 1) the composition of ostracod assemblages in lakes, springs, streams, and shortlived seasonal water bodies, 2) the geographical distribution of ostracods, and 3) the ecological characteristics of individual ostracod species. In total, 40 species were collected alive, and seven species were preserved as valves and empty carapaces. Of the 40 ostracod species, twelve were endemic to Lake Ohrid. The most common genus in the lake was Candona, represented by 13 living species, followed by Paralimnocythere, represented by fve living species. The most frequent species was Cypria obliqua. species with distinct distributions included Heterocypris incongruens, Candonopsis kingsleii, and Cypria lacustris. The most common species in shallow, fooded areas was H. incongruens, and the most prominent species in ditches was C. kingsleii. C. lacustris was widely distributed in channels, springs, lakes, and rivers. statistical analyses were performed on a "Lake Ohrid" dataset, comprising the subset of samples from Lake Ohrid alone, and an "entire" dataset comprising all samples collected. The unweighted pair group mean average (UPGMA) clustering was mainly controlled by species-specifc depth preferences. Canonical Correspondence Analysis (CCA) with forward selection identifed water depth, water temperature, and pH as variables that best explained the ostracod distribution in Lake Ohrid. The lack of signifcance of conductivity and dissolved oxygen in CCA of Ohrid data highlight the uniformity across the lake of the well-mixed waters. In the entire area, CCA revealed that ostracod distribution was best explained by water depth, salinity, conductivity, pH, and dissolved oxygen. salinity was probably selected by CCA due to the presence of Eucypris virens and Bradleystrandesia reticulata in short-lived seasonal water bodies. Water depth is an important, although indirect, infuence on ostracod species distribution, which is probably associated with other factors such as sediment texture and food supply. some species appeared to be indicators for multiple environmental variables, such as lake level and water temperature. Article 2013 English 07776276 Belgian Journal of Zoology 143 42 – 68 1 Lake Ohrid; autecology; endemism; fossil assemblage; geographical distribution; lacustrine deposit; lake water; multivariate analysis; ostracod; paleoclimate; paleoenvironment; reconstruction; sediment core; water temperature https://www.scopus.com/inward/record.uri?eid=2-s2.0-84886477267&partnerID=40&md5=e3cf68789cdbc4a695a9e78cc3704981 Cited by: 10 Julia Lorenschat Antje Schwalb article martin2013dating Existing radio-isotopic age constraints indicate that the global Palaeoproterozoic Lomagundi-Jatuli large, positive carbonate carbon isotopic excursion, with δ13C values &gt;+5‰, occurred between 2.2 and 2.06Ga. In the North Transfennoscandian Greenstone Belt of the Kola Peninsula, NW Russia, northern Norway and Finland, the Lomagundi-Jatuli Event is recorded in the carbonate rocks of the Umba and Kuetsjärvi Sedimentary Formations in the Imandra-Varzuga and Pechenga greenstone belts. In both areas, thick mafic volcanic units (Umba and Kuetsjärvi Volcanic Formations) overlie the carbon isotopic excursion-bearing sedimentary units. Overlying and younger sedimentary units contain carbonate rocks with δ13C values typically ranging between c. -1 and +3‰, signalling the termination of the Lomagundi-Jatuli excursion.Two new U-Pb ID-TIMS (isotope-dilution thermal ionisation mass spectrometry) zircon dates constrain this termination in both successions. The lower unit of the Il'mozero Sedimentary Formation is a cross- and parallel-bedded volcaniclastic greywacke derived largely from erosion of the underlying Umba Volcanic Formation. It has yielded detrital zircons with 207Pb/206Pb dates as young as 2055.5±2.3Ma, which is a maximum age for deposition and is inferred to date part of the underlying Umba volcanics. In Pechenga, the Kolosjoki Sedimentary Formation was intersected by a drill hole obtained by the ICDP (International Continental Scientific Drilling Program)-supported FAR-DEEP (Fennoscandian Arctic Russia-Drilling Early Earth Project) drilling programme. Zircons from a mafic fine tuff in this drill core have yielded a 207Pb/206Pb age of 2056.6±0.8Ma. This age is interpreted as an eruption age contemporaneous with sedimentation. The new age determinations overlap each other within uncertainty, and is within error of previously published detrital zircon ages of 2058±2Ma from the Kolosjoki Sedimentary Formation and 2049±28Ma from the Kuetsjärvi Volcanic Formation. Combined, these indicate that the Lomagundi-Jatuli excursion terminated across Fennoscandia by 2056.6±0.8Ma and may correlate with similar termination ages in Fennoscandia and the Transvaal, South Africa. © 2012. 2013 English 03019268 10.1016/j.precamres.2012.09.010 Precambrian Research 224 Elsevier 160--168 NERC Isotope Geosciences Laboratory, British Geological Survey, Keyworth NG125GG, United Kingdom; Department of Earth Sciences, University of St Andrews, St Andrews, Scotland, United Kingdom; Geological Survey of Norway, Postboks 6315 Slupen, 7491 Trondheim, Norway; Centre for Geobiology, University of Bergen, Postboks 7803, N-5020 Bergen, Norway; Tallinn Technical University, Institute of Geology, 19086 Tallinn, Estonia; Scottish Universities Environmental Research Centre, East Kilbride, Glasgow G75 0QF, Scotland, United Kingdom carbon isotope; carbonate rock; deposition; geochronology; greenstone belt; Proterozoic; radionuclide; sedimentation; uranium-lead dating; zircon, Fennoscandia; Finland; Kola Peninsula; Murmansk [Russian Federation]; Norway; Russian Federation; South Africa; Transvaal https://www.scopus.com/inward/record.uri?eid=2-s2.0-84867584239&doi=10.1016%2fj.precamres.2012.09.010&partnerID=40&md5=ec837ea3ef09acf151d9853f2ab60cdc cited By 40 Adam P Martin DJ Condon Anthony R Prave Victor A Melezhik Aivo Lepland Anthony E Fallick article Pollock2013219 Article 2013 10.1016/j.quascirev.2012.09.019 Quaternary Science Reviews 71 219 – 228 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84878946415&doi=10.1016%2fj.quascirev.2012.09.019&partnerID=40&md5=024bbd0bb04b5c5aa0f5827cd29581ec Cited by: 11 Edward W. Pollock Andrew B.G. Bush article Fortin2013147 Density measurements play a central role in the characterization of sediment profiles. When working with long records (>100m), such as those routinely obtained within the frame of the International Continental Scientific Drilling Program, several methods can be used, all of them varying in resolution, time-cost efficiency and source of errors within the measurements. This paper compares two relatively new non-destructive densitometric methods, CT-Scanning and the coherent/incoherent ratio from an Itrax XRF core Scanner, to data acquired from a Multi-sensor core logger Gamma Ray Attenuation Porosity Evaluator (MSCL Grape) and discrete measurements of dry bulk density, wet bulk density and water content. Quality assessment of density measurements is performed at low and high resolution along the Laguna Potrok Aike (LPA) composite sequence. Giving its resolution (0.4mm in our study), its high signal to noise ratio, we conclude that CT-Scan provides a precise, fast and cost-efficient way to determine density variation of long sedimentary record. Although more noisy that the CT-Scan measurements, coherent/incoherent ratio from the XRF core scanner also provides a high-resolution, reliable continuous measure of density variability of the sediment profile. The MSCL Grape density measurements provide actual density data and have the significant advantage to be completely non-destructive since the acquisition is performed on full cores prior to opening. However, the quality MSCL Grape density measurements can potentially be reduced by the presence of voids within the sediment core tubes and the dry and bulk density measurements suffers from sampling challenges and are time-consuming. © 2012 Elsevier Ltd. Article 2013 10.1016/j.quascirev.2012.08.024 Quaternary Science Reviews 71 147 – 153 Argentina; Laguna Potrok Aike; Santa Cruz [Argentina]; Vitaceae; Density measurement (specific gravity); Fruits; Gamma rays; Scanning; Sedimentology; Sediments; Bulk density measurement; Continental scientific drillings; CT-scan; Density variabilities; High signal-to-noise ratio; ICDP-project PASADO; Sediment densities; XRF; bulk density; cost-benefit analysis; measurement method; resolution; sampling; sediment core; signal-to-noise ratio; X-ray fluorescence; Computerized tomography https://www.scopus.com/inward/record.uri?eid=2-s2.0-84878920976&doi=10.1016%2fj.quascirev.2012.08.024&partnerID=40&md5=6b483615cf49844c544f5d8abbcb758e Cited by: 44 David Fortin Andrea Catalina Gebhardt Annette Hahn Pierre Kliem Agathe Lisé-Pronovost Rajarshi Roychowdhury Jacques Labrie Guillaume St-Onge article Morgavi2013119 Magma mixing may operate at any stage in the evolution of a magmatic system. The development of mixing is strongly controlled by fluid dynamics and its understanding requires a comprehensive physico-chemical approach in order to identify and interpret its occurrence in nature. Here, we experimentally study the physical and chemical interplays during the mixing of basaltic and rhyolitic natural melts from the Snake River Plains, USA. In particular, we present the results of the first high-temperature mixing experiments performed under controlled chaotic dynamic conditions, providing a new methodological approach to constrain the complexities of the mixing process between natural silicate melts.The mixing process is initially governed by the dynamics of stretching and folding of the melts, producing alternating flow bands. These bands increase the contact area between the end-members, which subsequently enhance chemical exchanges and thus contribute to the generation of regions with variable degrees of hybridization. We quantified the mobility of major and trace elements across contact areas, and analyzed the concentration variance decay induced by chemical diffusion. The analysis shows that elements diffuse with different efficiencies as the chemical gradient evolves and therefore, the achievement of hybrid compositions contrasts between elements. The approach introduced in this study can, in principle, be applied to mixing trends observed in nature in order to estimate the time-scales and degree of magma mixing evidenced across volcanic rocks/deposits. © 2012 Elsevier B.V. 2013 English 00092541 10.1016/j.chemgeo.2012.10.003 Chemical Geology 346 119-212 Department of Earth and Environmental Sciences, Ludwig-Maximilian-University, Theresienstrasse 41, 80333 Munich, Germany; Department Earth Sciences, University of Perugia, Piazza Universitá, 06100 Perugia, Italy; Department Geology and Geophysics, University of Liverpool, Liverpool, United Kingdom; U.S. Geological Survey, 973 Federal Center, Denver, CO 80225-0046, United States Chemical diffusion; Chemical gradients; Element mobility; Hybrid melts; Major and trace elements; Methodological approach; Mixing experiments; Snake river plains, Chemical analysis; Diffusion in solids; Experiments; Silicates, Mixing, basalt; concentration (composition); diffusion; experimental study; fluid dynamics; mixing; mobility; physicochemical property; rhyolite; silicate melt, Idaho; Snake River Plain; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-84876956502&doi=10.1016%2fj.chemgeo.2012.10.003&partnerID=40&md5=663d4a14f76585bb4f1f0ea50ca55d9a cited By 38 D. Morgavi D. Perugini C.P. De Campos W. Ertl-Ingrisch Y. Lavallée L. Morgan D.B. Dingwell article cp-9-567-2013 Marine isotope stages (MIS) 11 has been proposed as an analog for the present interglacial; however, terrestrial records of this time period are rare. Sediments from Lake El'gygytgyn (67 300 N, 172 50 E) in Far East Russia contain a 3.56 Ma record of climate variability from the Arctic. Here, we present the first terrestrial Arctic reconstruction of environmental and climatic changes from MIS 8 through 12 (289 to 464 ka) using organic geochemical proxies. Terrestrial vegetation changes, as revealed by plant leaf wax (n-alkane) indices and concentrations of arborinol (a biomarker for trees), show increased tree cover around the lake during interglacial periods, with higher concentrations observed during MIS 11 as compared to MIS 9. A similar pattern is also observed in records of aquatic productivity revealed by molecular indicators from dinoflagellates (dinosterol), eustigmatophyte algae (long-chain (C28-C32) 1, 15 n-alkyl diols) in addition to short-chain n-alkanes, where aquatic productivity is highest during MIS 11. Changes recorded in these molecular proxies show a similar structure to relative temperature variability as recorded by the MBT/CBT (Methylation of Branched Tetraether/Cyclization of Branched Tetraether) paleothermometer, based on branched glycerol dialkyl glycerol tetraethers (GDGTs). Additionally, relative MBT/CBT temperature changes generally track pollen and diatom 18O temperature estimates, compiled by other studies, which suggest glacial-interglacial temperature changes of 9 to 12 C. These records of environmental and climatic change indicate Arctic sensitivity to external forcings such as orbital variability and atmospheric greenhouse gas concentrations. Overall, this study indicates that organic geochemical analyses of the Lake El'gygytgyn sediment archive can provide critical insight into the response of lake ecosystems and their sensitivity in high latitude regions. © Author(s) 2013. 2013 English 18149324 10.5194/cp-9-567-2013 Climate of the Past 9 567-581 Climate Systems Research Center, Department of Geosciences, University of Massachusetts Amherst, Amherst, MA 01003, United States 2 alga; biogeochemical cycle; biomarker; climate change; environmental change; greenhouse gas; interglacial; lacustrine deposit; latitude; marine isotope stage; temperature effect; vegetation, Arctic; Chukchi; Elgygytgyn Lake; Far East; Russian Federation https://cp.copernicus.org/articles/9/567/2013/ cited By 20 R. M. D'Anjou J. H. Wei I. S. Castaneda J. Brigham-Grette S. T. Petsch D. B. Finkelstein article Vavryčuk2013189 We have analyzed 463 micro-earthquakes in the magnitude range from 0.5 to 3.8 that occurred during the 2008 earthquake swarm in West Bohemia, Czech Republic, in order to screen the detailed structure of the focal zone situated at depths between 7 and 11. km. The double-difference location method was applied to records of 22 local seismic stations with an epicentral distance of less than 25. km in order to retrieve highly accurate locations of hypocenters with an accuracy of less than 20. m. The hypocenters are well-clustered and distinctly map the system of activated faults. The fault system has a complex geometry being composed of several fault segments with different orientations. Some of the segments intersect each other. The orientations of the segments coincide well with the focal mechanisms. We have introduced and evaluated the so-called fault instability of the individual fault segments. The fault instability ranges from 0 (most stable faults) to 1 (most unstable faults) and measures the susceptibility of the fault to be activated under specified stress. In the West Bohemia focal zone, two fault segments are optimally oriented with respect to the tectonic stress being characterized by an instability value higher than 0.9. Tractions on these fault segments are concentrated in the Mohr's diagram in the area of validity of the Mohr-Coulomb failure criterion and the associated micro-earthquakes are mainly shear. The other fault segments are slightly misoriented with instability values between 0.7 and 0.9, and the shear traction is significantly lower. These earthquakes are probably more tensile and activated most likely by the local redistribution of Coulomb stress during swarm activity. © 2013 Elsevier B.V. Article 2013 English 00401951 10.1016/j.tecto.2013.01.025 Tectonophysics 590 189 – 195 Bohemia; Czech Republic; Earthquakes; Stability; Earthquake location; Failure criteria; Fault friction; Focal mechanism; Tectonic stress; Coulomb criterion; earthquake event; earthquake hypocenter; earthquake magnitude; focal mechanism; image resolution; microearthquake; Faulting https://www.scopus.com/inward/record.uri?eid=2-s2.0-84875375854&doi=10.1016%2fj.tecto.2013.01.025&partnerID=40&md5=113001a50720526c03138c06ce101ce2 Cited by: 71 Václav Vavryčuk Fateh Bouchaala Tomáš Fischer article Lisé-Pronovost201391 Paleomagnetic inclination, declination and relative paleointensity were reconstructed from the sediments of Laguna Potrok Aike in the framework of the International Continental scientific Drilling Program (ICDP) Potrok Aike maar lake Sediment Archive Drilling prOject (PASADO). Here we present the u-channel-based full vector paleomagnetic field reconstruction since 51.2ka cal BP. The relative paleointensity proxy (RPI) was built by normalising the natural remanent magnetisation with the anhysteretic remanent magnetisation using the average ratio at 4 demagnetisation steps part of the ChRM interval (NRM/ARM10-40mT). A grain size influence on the RPI was removed using a correction based on the linear relationship between the RPI and the median destructive field of the natural remanent magnetisation (MDFNRM). The new record is compared with other lacustrine and marine records and stacks from the mid- to high-latitudes of the Southern Hemisphere, revealing consistent millennial-scale variability, the identification of the Laschamp and possibly the Mono Lake geomagnetic excursions, and a direction swing possibly associated to the Hilina Pali excursion at 20ka cal BP. Nonetheless, a global-scale comparison with other high-resolution records located on the opposite side of the Earth and with various dipole field references hint at a different behaviour of the geomagnetic field around southern South America at 46ka cal BP. © 2012 Elsevier Ltd. Article 2013 10.1016/j.quascirev.2012.05.012 Quaternary Science Reviews 71 91 – 108 Argentina; Laguna Potrok Aike; Santa Cruz [Argentina]; South America; Lakes; Magnetization; Sedimentology; ICDP-project PASADO; Laguna potrok aike; Paleomagnetism; Relative paleointensity; Secular variation; Southern Hemisphere; geomagnetism; grain size; lacustrine deposit; paleomagnetism; Pleistocene; proxy climate record; reconstruction; resolution; secular variation; Southern Hemisphere; Geomagnetism https://www.scopus.com/inward/record.uri?eid=2-s2.0-84878954637&doi=10.1016%2fj.quascirev.2012.05.012&partnerID=40&md5=7a63f9b83c846ae22d3d848cb22d410c Cited by: 42 Agathe Lisé-Pronovost Guillaume St-Onge Claudia Gogorza Torsten Haberzettl Michel Preda Pierre Kliem Bernd Zolitschka article cp-9-433-2013 2013 10.5194/cp-9-433-2013 Climate of the Past 9 433-446 1 https://cp.copernicus.org/articles/9/433/2013/ P. S. Minyuk T. V. Subbotnikova L. L. Brown K. J. Murdock article Jovanovska201315 A lectotype and isolectotype for Navicula budayana Pantocsek = Diploneis budayana (Pantocsek) Hustedt, Navicula ostracodarum Pantocsek = Diploneis ostracodarum (Pantocsek) Jovanovska, Nakov & Levkov and Navicula praeclara Pantocsek = Diploneis praeclara (Pantocsek) Cleve-Euler from Köpecz, Neogene fossil deposits in Romania have been made. Typification for each species was based on Pantocsek's original images and material deposited at the Hungarian Natural History Museum (BP). Unfortunately, the type slides for Diploneis budayana, D. ostracodarum and D. praeclara were lost or destroyed during the course of World War II. Therefore, authentic material from the type locality Köpecz at BP was used to designate the lectotypes for these three species. Detailed LM and SEM observations have been assigned for each taxon, in order to ascertain the variation in valve morphology. Taxonomic descriptions and comments are made for each species. Typification of taxa described by Pantocsek would potentially affect further stratigraphic, comparative or molecular phylogenetic work not just for Tertiary floras but for Recent floras as well. In particular, studies concerning comparisons of these species between localities, such as Lake Ohrid, will greatly benefit from this work. The outcome of such studies will shed light on the evolutionary and biogeographic history of diatoms in the context of geologic events on the Balkan Peninsula. © 2013 Magnolia Press. Article 2013 English 11793163 10.11646/phytotaxa.137.1.2 Phytotaxa 137 15 – 26 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84885443057&doi=10.11646%2fphytotaxa.137.1.2&partnerID=40&md5=08e6e5fb42c6a2274ec15bb301578866 Cited by: 3 Elena Jovanovska Krisztina Buczkó Nadja G. Ognjanova-Rumenova Teofil Nakov Zlatko Levkov article Oehlerich201346 The monoclinic mineral ikaite (CaCO3 · 6H2O) and its pseudomorphs are potentially important archives for palaeoenvironmental reconstructions. Natural ikaite occurs in a small temperature range near freezing point and is reported mainly from marine and only rarely from continental aquatic environments. Ikaite transforms to more stable anhydrous forms of CaCO3 after an increase in temperature or when exposed to atmospheric conditions. The knowledge about conditions for natural ikaite formation, its stable isotope fractionation factors and isotopic changes during transformation to calcite is very restricted. Here, for the first time, primary precipitation of idiomorphic ikaite and its calcite pseudomorphs are reported from a subsaline lake, Laguna Potrok Aike, in southern Argentina. The calculated stable oxygen isotope fractionation factor between lake water and ikaite-derived calcite (αPAI=1.0324 at a temperature of 4.1°C) is close to but differs from that of primarily inorganically precipitated calcite. Pseudomorphs after ikaite rapidly disintegrate into calcite powder that is indistinguishable from μm-sized calcite crystals in the sediment record of Laguna Potrok Aike suggesting an ikaite origin of sedimentary calcites. Therefore, the Holocene carbonates of Laguna Potrok Aike have the potential to serve as a recorder of past hydrological variation. © 2012 Elsevier Ltd. Article 2013 10.1016/j.quascirev.2012.05.024 Quaternary Science Reviews 71 46 – 53 Argentina; Laguna Potrok Aike; Santa Cruz [Argentina]; Calcium carbonate; Isotopes; Lakes; Lasers; Minerals; Oxygen; Sedimentary rocks; Aquatic environments; Atmospheric conditions; ICDP project PASADO; Oxygen isotope fractionations; Palaeoenvironmental reconstruction; Stable isotope fractionations; Stable isotopes; Stable oxygen isotopes; calcite; calcium carbonate; freezing; Holocene; ikaite; isotopic fractionation; lacustrine deposit; lacustrine environment; marine environment; oxygen isotope; paleoenvironment; precipitation (chemistry); reconstruction; sediment chemistry; stable isotope; temperature effect; Calcite https://www.scopus.com/inward/record.uri?eid=2-s2.0-84878948287&doi=10.1016%2fj.quascirev.2012.05.024&partnerID=40&md5=0f1d2783c26f26f8215a298c18d989fe Cited by: 27 Markus Oehlerich Christoph Mayr Erika Griesshaber Andreas Lücke Oliver M. Oeckler Christian Ohlendorf Wolfgang W. Schmahl Bernd Zolitschka article Sumita20131 The historically active Nemrut Volcano (2,948 m asl) (Eastern Anatolia), rising close to the western shore of huge alkaline Lake Van, has been the source of intense Plinian eruptions for &gt;530,000 years (drilled lake sediments). About 40 widespread, newly recognized trachytic and less common rhyolitic fallout tephras and ca. 12 interbedded ignimbrites, sourced in Nemrut Volcano, are documented in stratigraphic traverses throughout an area of &gt;6,000 km2 mostly west of Lake Van. Phenocrysts in the moderately peralkaline trachytes and rarer large-volume comenditic rhyolites comprise anorthoclase, hedenbergite-augite, fayalite and, especially in trachytic units, augite, minor aenigmatite, apatite and quartz, and rare chevkinite and zircon. Dacitic to rhyolitic tephras from nearby calcalkalic Süphan Volcano (4,058 m asl), locally interbedded with Nemrut tephras, are characterized by disequilibrium phenocryst assemblages (biotite, augitic clinopyroxene and hypersthene, minor olivine, common crystal clots and/or, in some deposits, amphibole). The magma volume (DRE) of the largest Nemrut tephra sheet (AP-1) described in detail may exceed 30 km3. Extreme facies and systematic compositional changes are documented in the ca. 30 ka Nemrut Formation (NF) deposits formed from one large and complex eruption (thick rhyolitic fallout overlain by ignimbrite, welded agglutinate, overbank surge deposits, and final more mafic fallout deposits). Common evidence of magma mixing in Nemrut ignimbrites reflects eruption from compositionally zoned magma reservoirs. Several young Çekmece Formation trachytes overlying ca. 30 ka old NF deposits and the late trachytes of the NF deposits show compositional affinities to tephra from Süphan Volcano possibly due to temporary influx of Süphan magmas into the Nemrut system following the evacuation of &gt;10 km3 magma (DRE) during the caldera-forming NF eruption. Axes of large fallout fans are dominantly SW-NE but W-E in the younger sheets resembling the direction of the present dominant wind field. Growth of Nemrut volcanic edifice and its peripheral domes since before 0.5 Ma in the hinge area between the Van and Muş tectonic basins is likely to have been the major factor in isolating Lake Van basin thus initiating the origin and subsequent alkaline evolution of the lake. This alkalinity was later significantly controlled by climate forcing. Internal forcing mechanisms (volcanic and geodynamic) may also have contributed to major lake level changes in addition to climate forcing. © 2013 Springer-Verlag Berlin Heidelberg. 2013 English 02588900 10.1007/s00445-013-0714-5 Bulletin of Volcanology 75 Springer Verlag 1-32 GEOMAR Helmholtz Centre for Ocean Research Kiel, Wischhofstr. 1, 24148 Kiel, Germany 5 basin evolution; ignimbrite; lithostratigraphy; peralkaline rock; phenocryst; plinian eruption; rhyolite; tephra; trachyte; volcanic eruption; volcanism, Bitlis; Lake Van; Nemrut; Turkey, Plinia; Trachytes https://www.scopus.com/inward/record.uri?eid=2-s2.0-84876681356&doi=10.1007%2fs00445-013-0714-5&partnerID=40&md5=196eeb628c8510172b636594a10381a8 cited By 49 M. Sumita H.-U. Schmincke article Sumita201315 Thirty-two new single crystal ages document 400. 000. years of widespread explosive volcanism of historically active Nemrut Volcano towering over huge alkaline Lake Van (Eastern Anatolia). The dated deposits were selected to monitor the volcanic and compositional evolution of Nemrut Volcano through time and thus to provide a rigorous temporal framework for the tephra record of the PaleoVan Drilling Project. Tephra samples were taken from large-volume deposits or those that occur in medial to distal localities, well-exposed stratigraphic sections or from the initial phase of an eruptive sequence. Mainly fallout deposits were chosen because most ignimbrites show more complex and corroded feldspar populations owing to compositional zoning and magma mixing. Moreover, fallout deposits held the promise to be more clearly identifiable with-and correlatable to->. 300 tephra layers in the PaleoVan drill cores, even though commonly in amounts marginal or insufficient in thickness to allow well-supported single crystal dating. The crystals dated are dominantly anorthoclase, the main phenocryst phase in the trachytic to rhyolitic, slightly to strongly peralkaline Nemrut magmas. Ages obtained so far range from ca. 400. ka to ca. 30. ka for Nemrut Volcano. The causes of significant changes in the frequency, volume and composition of tephra layers per unit time are discussed in terms of external (erosion, climate changes, geodynamic factors) and internal forcing (changes in magma supply and composition and incubation periods preceding large volume rhyolitic eruptions). For example, the low frequency of tephra layers deposited prior to ca. 200. ka may be due to low explosive activity, severe erosion between MIS 9 and MIS 11, or both. Nevertheless, the overall frequency of explosive eruptions appears to have increased during the past ca. 200. ka. We also recognize a slight peak in explosive eruptions during warm periods (e.g. MIS 5 and MIS 7) and speculate on lithospheric unloading triggering increased partial melting or magma reservoir unloading following massive glacier melting. The ages of 5 dated ignimbrites span ca. 250. 000. years suggesting that Nemrut Volcano went through a polycyclic evolution with multiple caldera collapses and major pyroclastic flow eruptions, the oldest dated so far as 265. ka. The widely held view of the impressive Nemrut Caldera now dated to have formed at ca. 30. ka, as the main paroxysmal event during the evolution of the volcano is no longer tenable. Distinct and coherent compositional characteristics, especially in trace element concentrations, characterize several groups of trachytic tephras. We speculate that the growth of Nemrut Volcano caused the isolation of the Lake Van basin. On account of their mineralogical (anorthoclase, hedenbergite, fayalite, aenigmatite) and alkalic chemical compositions and large volume, dated Nemrut fallout tephras are likely to represent excellent markers in lakes and other sites of paleoclimatological or archeological interest in neighboring countries to the northeast of Lake Van as far as the Caspian Sea in what may be called the East Anatolian Tephra Province. © 2012 Elsevier B.V. 2013 English 03770273 10.1016/j.jvolgeores.2012.12.009 Journal of Volcanology and Geothermal Research 253 Elsevier B.V. 15-34 GEOMAR Helmholtz Centre for Ocean Research Kiel, Wischhofstr. 1-3, 24148 Kiel, Germany Alkalinity; Climate change; Deposits; Erosion; Explosives; Fallout; Feldspar; Feldspar deposits; Lakes; Melting; Reservoirs (water); Single crystals; Stratigraphy; Submarine geophysics; Trace elements; Unloading, Chemical compositions; Compositional characteristics; Compositional evolution; Compositional zoning; East Anatolian Tephra Province; Explosive volcanism; Lake vans; Trace element concentrations, Volcanoes, argon-argon dating; explosive volcanism; ignimbrite; marine isotope stage; pyroclastic flow; temporal evolution; tephra; volcanic eruption, Bitlis; Lake Van; Nemrut; Turkey https://www.scopus.com/inward/record.uri?eid=2-s2.0-84872554483&doi=10.1016%2fj.jvolgeores.2012.12.009&partnerID=40&md5=19be418557701f4821eb93d4f3ea42f4 cited By 51 M. Sumita H.-U. Schmincke article Osinski2013347 It has long been suggested that hydrothermal systems might have provided habitats for the origin and evolution of early life on Earth, and possibly other planets such as Mars. In this contribution we show that most impact events that result in the formation of complex impact craters (i.e., >2-4 and >5-10. km diameter on Earth and Mars, respectively) are potentially capable of generating a hydrothermal system. Consideration of the impact cratering record on Earth suggests that the presence of an impact crater lake is critical for determining the longevity and size of the hydrothermal system. We show that there are six main locations within and around impact craters on Earth where impact-generated hydrothermal deposits can form: (1) crater-fill impact melt rocks and melt-bearing breccias; (2) interior of central uplifts; (3) outer margin of central uplifts; (4) impact ejecta deposits; (5) crater rim region; and (6) post-impact crater lake sediments. We suggest that these six locations are applicable to Mars as well. Evidence for impact-generated hydrothermal alteration ranges from discrete vugs and veins to pervasive alteration depending on the setting and nature of the system. A variety of hydrothermal minerals have been documented in terrestrial impact structures and these can be grouped into three broad categories: (1) hydrothermally-altered target-rock assemblages; (2) primary hydrothermal minerals precipitated from solutions; and (3) secondary assemblages formed by the alteration of primary hydrothermal minerals. Target lithology and the origin of the hydrothermal fluids strongly influences the hydrothermal mineral assemblages formed in these post-impact hydrothermal systems. There is a growing body of evidence for impact-generated hydrothermal activity on Mars; although further detailed studies using high-resolution imagery and multispectral information are required. Such studies have only been done in detail for a handful of martian craters. The best example so far is from Toro Crater (Marzo, G.A., Davila, A.F., Tornabene, L.L., Dohm, J.M., Fairèn, A.G., Gross, C., Kneissl, T., Bishop, J.L., Roush, T.L., Mckay, C.P. [2010]. Icarus 208, 667-683). We also present new evidence for impact-generated hydrothermal deposits within an unnamed ∼32-km diameter crater ∼350. km away from Toro and within the larger Holden Crater. Synthesizing observations of impact craters on Earth and Mars, we suggest that if there was life on Mars early in its history, then hydrothermal deposits associated with impact craters may provide the best, and most numerous, opportunities for finding preserved evidence for life on Mars. Moreover, hydrothermally altered and precipitated rocks can provide nutrients and habitats for life long after hydrothermal activity has ceased. © 2012 Elsevier Inc. 2013 10.1016/j.icarus.2012.08.030 Icarus 224 347-363 Centre for Planetary Science and Exploration, University of Western Ontario, London, ON N6A 5B7, Canada; Dept. of Earth Sciences, University of Western Ontario, London, ON N6A 5B7, Canada; Dept. of Physics and Astronomy, University of Western Ontario, London, ON N6A 5B7, Canada; School of Physics and Astronomy, University of Edinburgh, Edinburgh EH9 3JZ, United Kingdom; Dept. of Geology, University of Aberdeen, Aberdeen AB24 3UE, United Kingdom 2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84878256506&doi=10.1016%2fj.icarus.2012.08.030&partnerID=40&md5=eb6b8be9ff0c25fb218e77689c3c5947 cited By 178 G.R. Osinski L.L. Tornabene N.R. Banerjee C.S. Cockell R. Flemming M.R.M. Izawa J. McCutcheon J. Parnell L.J. Preston A.E. Pickersgill A. Pontefract H.M. Sapers G. Southam article NobreSilva2013659 The 3500 m deep Hawai'i Scientific Drilling Project core provides a ~680 kyr record of the magmatic history and source components of Mauna Kea volcano. We report high-precision Pb-Sr-Nd isotopic compositions of 40 basalts from the last 408 m of the final drilling phase (HSDP2-B and HSDP2-C) and show that these lowermost basalts represent the early shield stage of Mauna Kea's growth history. Two sample groups are distinguished based on their isotopic variability compared to the rest of the core. Over a depth interval of 210 m (3098.2-3308.2 mbsl), the basalts show very restricted isotopic variation and represent sampling of a relatively homogeneous source. Samples from the bottom 192 m record the largest range of 206Pb/204Pb and 208Pb/204Pb in the core, reflecting the greater isotopic variability of the earlier stages of volcanism compared to subsequent stages. The heterogeneity of Mauna Kea lavas is explained by mixing variable proportions of four distinct components intrinsic to the Hawaiian mantle plume. One of these components, Kea, is a prevalent and long-lived composition within the Hawaiian plume, whereas the other three components are involved at different stages of the volcano's history and contribute to the short-term isotopic variability of Mauna Kea. The compositional similarity of the Kea component to "C" and to the super-chondritic bulk-silicate Earth suggests that Kea may be part of the primitive mantle of a non-chondritic Earth. Other Pacific oceanic island basalts share Kea-like compositions, indicating that the Kea component is a common, widespread composition within the Pacific deep mantle. ©2013. American Geophysical Union. All Rights Reserved. Article 2013 English 15252027 10.1002/ggge.20047 Geochemistry, Geophysics, Geosystems 14 Blackwell Publishing Ltd 659 – 676 3 Hawaii [(ISL) Hawaiian Islands]; Hawaii [United States]; Hawaiian Islands; Mauna Kea; Pacific Ocean; United States; Basalt; Core samples; Lead; Silicates; Strontium; Thermal plumes; Volcanoes; HSDP2; Mantle heterogeneity; Mantle plume; Mauna keas; Ocean island basalts; Pb-Sr-Nd isotope systematics; isotopic composition; mantle chemistry; mantle plume; mantle source; Ocean Drilling Program; ocean island basalt; volcanism; Isotopes https://www.scopus.com/inward/record.uri?eid=2-s2.0-84879803379&doi=10.1002%2fggge.20047&partnerID=40&md5=ec636da6ec7fc641e12c50c1c39a9e9c Cited by: 29; All Open Access, Bronze Open Access, Green Open Access Inês G. Nobre Silva Dominique Weis James S. Scoates article Gulick201331 Geophysical data indicate that the 65.5 million years ago Chicxulub impact structure is a multi-ring basin, with three sets of semicontinuous, arcuate ring faults and a topographic peak ring (PR). Slump blocks define a terrace zone, which steps down from the inner rim into the annular trough. Fault blocks underlie the PR, which exhibits variable relief, due to target asymmetries. The central structural uplift is >10 km, and the Moho is displaced by 1-2 km. The working hypothesis for the formation of Chicxulub is: a 50 km radius transient cavity, lined with melt and impact breccia, formed within 10 s of the impact, and within minutes, weakened rebounding crust rose kilometers above the surface, the transient crater rim underwent localized deformation and collapsed into large slump blocks, resulting in a inner rim at 70-85 km radius, and outer ring faults at 70-130 km radius. The overheightened structural uplift collapsed outward, buried the inner slump blocks, and formed the PR. Most of the impact melt was ultimately emplaced as a coherent <3 km thick melt sheet within the central basin that shallows within the inner regions of the PR. Smaller pockets of melt flowed into the annular trough. Subsequently, slope collapse, ejecta, ground surge, and tsunami waves infilled the annular trough and annular basin with sediments up to 3 km and 900 m thick, respectively. Testing this working hypothesis requires direct observation of the impactites, within and adjacent to the PR and central basin. Key PointsA review of all geophysical data imaging ChicxulubSummary of the key features of the impact structureAn assessment of the relative timing of impact processes © 2013. American Geophysical Union. All Rights Reserved. 2013 10.1002/rog.20007 Reviews of Geophysics 51 31-52 University of Texas, Institute for Geophysics, Jackson School of Geosciences, 10100 Burnet Rd., Austin, TX 78758, United States; Bullard Laboratories, Department of Earth Sciences, University of Cambridge, Cambridge, United Kingdom; Department of Earth Sciences, University of Western Ontario, London ON, Canada; Department of Earth Science and Engineering, Imperial College London, London, United Kingdom; Instituto de Geofísica, Universidad Nacional Autõnoma de México, Ciudad Universitaria, Coyoacán, Mexico 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84879075868&doi=10.1002%2frog.20007&partnerID=40&md5=bfb0665e34df7b8cbff5a8ffb6df63e9 cited By 62 S.P.S. Gulick G.L. Christeson P.J. Barton R.A.F. Grieve J.V. Morgan J. Urrutia-Fucugauchi article salminen2013kolosjoki 2013 Chemical Geology 362 Elsevier 165--180 Paula E Salminen Juha A Karhu Victor A Melezhik article Salminen2013165 Article 2013 10.1016/j.chemgeo.2013.10.018 Chemical Geology 362 165 – 180 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84889086602&doi=10.1016%2fj.chemgeo.2013.10.018&partnerID=40&md5=43c6d80e95f32ca76d77e78cef2794f9 Cited by: 5 Paula E. Salminen Juha A. Karhu Victor A. Melezhik article Zhao201383 In order to define the provenance change across the nonconformable boundary between the second and the third members of the Upper Cretaceous Nenjiang Formation (Campanian) in the north-central area of the Songliao Basin, two sandstone samples above (sample a-1 from the fourth member of the Nenjiang) and below (sample z-1 from the first member of the Yaojia Formation) the nonconformity were collected from core holes. U-Pb dating was performed on detrital zircons separated from the three sandstone samples. Detrital zircons from sample a-1 have dominant age populations of 100-110. Ma, 190-220. Ma, and ~. 1800. Ma, and sample z-1 has dominant ages of 130-150. Ma and ~. 350. Ma. This paper demonstrates that the provenance of the fourth member of the Nenjiang Formation is significantly different from the first member of the Coniacian Yaojia Formation. The provenance above the nonconformity became much more complex and the eastern source increased significantly, while the western source sharply declined. The main source areas of the fourth member of the Nenjiang Formation are mainly the Zhangguangcai Range, the eastern Lesser Xiang'an Range and the southeast of Songliao Basin. The dominant provenance of the first member of the Yaojia Formation is the northern, the central and the southern Great Xing'an Range. According to the depositional ages and combining the latest seismic stratigraphic profiles in the Songliao Basin, the tectonic inversion of the eastern Songliao Basin began between 73. Ma and 87. Ma, which differs from the previous age of 73. Ma. © 2012 Elsevier B.V. 2013 English 00310182 10.1016/j.palaeo.2012.03.017 Palaeogeography, Palaeoclimatology, Palaeoecology 385 83-94 School of Earth Science and Resources, China University of Geosciences, Beijing 100083, China; State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing 100083, China; Sinopec International Petroleum Exploration and Production Corporation, Beijing 100029, China; Institute of Exploration and Development of Daqing Oil field Company Ltd, Daqing 163712, China Campanian; detrital deposit; provenance; seismic stratigraphy; tectonic evolution; unconformity; uranium-lead dating; zircon, China; Da Hinggan Mountains; Heilongjiang; Nen Basin; Songliao Basin; Xiao Hinggan Mountains, Coniacian https://www.scopus.com/inward/record.uri?eid=2-s2.0-84879869790&doi=10.1016%2fj.palaeo.2012.03.017&partnerID=40&md5=006dacac58be93dea6c7ee2c7dfdffd3 cited By 43 B. Zhao C. Wang X. Wang Z. Feng article Wang2013275 Cretaceous climate data of the long-lived Cretaceous Songliao Basin (SB) in eastern Asia is correlated and compared with the Western Interior Seaway (WIS) on the northern American plate, in order to understand better the dynamics of the Earth's past 'greenhouse' climates. Nearly continuous Late Cretaceous terrestrial deposition in the Songliao Basin is represented by two cores totaling 2431m in length. The Turonian-Maastrichtian age of the section is based on integrated stratigraphy, and is comparable in age with Upper Cretaceous strata in the WIS. Being consistent with global trends, the dynamic Late Cretaceous climates of both the SB and WIS gradually cooled from the warmest Albian-Cenomanian time to the end of the Maastrichtian with several intervening warm periods as did the global climate. However regional differences existed, the Songliao Basin climate was humid to semi-humid, warm temperate-subtropical and the Western Interior Seaway was in the humid, warm temperate zone and experienced only moderate climatic changes. The shifts of oxygen isotope data in the Songliao Basin were frequent and abrupt, whereas WIS records more gradual change affected mainly by fresh-water runoff mixing with southern Tethyan and northern Arctic waters. Sedimentary cycles of eccentricity, obliquity and precession bands are recorded in both the SB and WIS basins. The sedimentary cycles in the WIS and SB are interpreted to be related to variations of the wet/dry runoff cycles, which indicate that orbital forcing played an important role in global climate change in Late Cretaceous. The most favorable condition for organic carbon burial in both the SB and WIS basin was bottom water anoxia regardless of the cause of the anoxia. But the organic carbon burial rate was usually much higher in the Songliao Lake than in the WI epeiric sea suggesting that giant lakes may serve as important sinks of atmospheric CO2. In both basins organic-rich deposits formed during a rise in water level and incursion of saline waters. The integration of paleoclimate data from Cretaceous marine deposits and terrestrial sedimentary record will promote our understanding of the Cretaceous 'greenhouse' climate change and may provide insights for a future greenhouse world. © 2013 Elsevier B.V. 2013 English 00128252 10.1016/j.earscirev.2013.08.016 Earth-Science Reviews 126 275-299 State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing 100083, China; Department of Geosciences, University of Tulsa, Tulsa, OK 74104, United States; Department of Geological and Envrironmental Sciences, Stanford University, 397 Panama Mall, CA 94305, United States; College of Earth Sciences, Jilin University, Changchun 130061, China; U.S. Geological Survey, P.O. Box 25046, MS 980, Denver, CO 80225-0046, United States; School of the Earth Science and Resources, China University of Geosciences, Beijing 100083, China; Precision Stratigraphy Associates, Tulsa, OK 74104, United States Albian; carbon sink; Cenomanian; climate variation; Cretaceous; deposition; eccentricity; global climate; greenhouse effect; lacustrine deposit; Maastrichtian; organic carbon; oxygen isotope; paleoclimate; runoff; sediment core; stratabound deposit; stratigraphy; Turonian; water level, China; Songliao Basin https://www.scopus.com/inward/record.uri?eid=2-s2.0-84885099265&doi=10.1016%2fj.earscirev.2013.08.016&partnerID=40&md5=31dac0e7e82eb14e5c818b2094c2f463 cited By 100 C. Wang R.W. Scott X. Wan S.A. Graham Y. Huang P. Wang H. Wu W.E. Dean L. Zhang article Wan201331 The Songliao Basin is the largest Cretaceous oil and gas-producing lacustrine basin in China, with its greatest aerial extent in the middle Cretaceous. A coring program (SK1) has to date yielded 2485.89m of continuous core (96.46% recovery) and provides significant material for Cretaceous research. The sequence of the core consists mainly of lacustrine sandstone, dark grey mudstone, shale and oil-shale. The Upper Cretaceous stratigraphic section has been subdivided into the Quantou, Qingshankou, Yaojia, Nenjiang, Sifangtai and Mingshui formations in ascending order. Late Cretaceous microfossils are diverse and abundant. A detailed biostratigraphic study has subdivided the sequence into high precision biozones: 21 ostracode assemblages, 10 phytoplankton assemblages, 7 palynological zones and 4 charophyta assemblages, respectively. In addition, marine foraminifera were first discovered from the basin. Three 206Pb/238U ages and one 40Ar/39Ar age were analysed. Ten local magnetozones have been recognised in the SK1 (North), and two magnetozones have been indicated in the SK1 (South). Based on biostratigraphy, high-resolution magnetostratigraphy and SIMS U-Pb zircon analyses, the SK1 stratigraphy is correlated with Upper Cretaceous stages in the International Geologic Time Scale. The upper part of the Quantou Formation is the lower Turonian; the Qingshankou Formation is the upper Turonian-lower Coniacian; the Yaojia Formation is from the upper Coniacian to middle Santonian; the Nenjiang Formation is the upper Santonian to middle Campanian; the Sifangtai Formation is limited to the upper Campanian; and the Mingshui Formation is the uppermost Campanian to Maastrichtian. It is likely that the upper part of the Mingshui Formation belongs to the Paleocene, and the K/Pg boundary is within the Member 2 of the Mingshui Formation around the depth of 328m by new micropalaeontologic and magnetostratigraphic data. © 2012 Elsevier B.V. 2013 English 00310182 10.1016/j.palaeo.2012.10.024 Palaeogeography, Palaeoclimatology, Palaeoecology 385 31-43 State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Xueyuan Lu 29, Beijing 100083, China; Department of Geosciences, University of Tulsa, Tulsa, OK 74104, United States; College of Earth Sciences, Jilin University, Changchun 130061, China; Exploration and Development Research Institute of Daqing Oil Field Corporation Ltd., Daqing, Heilongjiang 163712, China biostratigraphy; biozonation; Campanian; charophyte; chronostratigraphy; Coniacian; core analysis; Cretaceous-Tertiary boundary; foraminifera; gas production; hydrocarbon reserve; hydrocarbon reservoir; lacustrine deposit; Maastrichtian; magnetostratigraphy; marine environment; microfossil; micropaleontology; mudstone; oil production; oil shale; ostracod; palynology; phytoplankton; sandstone; Santonian; stratigraphic correlation; timescale; Turonian; uranium-lead dating, China; Songliao Basin, Charales; Coniacian; Foraminifera; Ostracoda https://www.scopus.com/inward/record.uri?eid=2-s2.0-84879874669&doi=10.1016%2fj.palaeo.2012.10.024&partnerID=40&md5=0fd7273e77763a9b77cc1323caba25c7 cited By 143 X. Wan J. Zhao R.W. Scott P. Wang Z. Feng Q. Huang D. Xi article li2013late 2013 Acta Micropalaeontologica Sinica 30 1-16 1 Sha Li YY Zhang HY Qu MY Wang XQ Wan Acta Micropalaeontologica Sinica others article Townend20133801 We present a geophysical characterization at 0.1-100 m scales of a major plate-bounding continental fault in a late-interseismic state. The Alpine Fault produces MW∼8 earthquakes every 200-400 years and last ruptured in 1717 AD. Wireline geophysical logs and rock cores extending from one side of the Alpine Fault to the other were acquired in two boreholes drilled in 2011 at Gaunt Creek during the first phase of the Deep Fault Drilling Project (DFDP-1). These data document ambient conditions under which the next Alpine Fault earthquake will occur. Principal component analysis of the wireline logging data reveals that >80% of the variance is accounted for by electrical, acoustic, and natural gamma properties, and preliminary multivariate classification enables the lithologies of sections of missing core to be reconstructed from geophysical measurements. The fault zone exhibits systematic variations in properties consistent with common processes of progressive alteration and comminution near the principal slip zone, superimposed on different protolith compositions. Our observations imply that the fault zone has the opposite sense of elastic asymmetry at 0.1-100 m scales to that of the crustal-scale orogen imaged by remote geophysical methods. On the basis of the fault-zone scale asymmetry, the bimaterial interface model of preferred earthquake rupture directions implies a northeastward direction of preferred Alpine Fault rupture. On-going characterization of the structural and hydraulic architecture of the Alpine Fault will improve our understanding of the relationship between in situ conditions, earthquake rupture processes, and the hazards posed by future earthquakes. © 2013. American Geophysical Union. All Rights Reserved. 2013 English 15252027 10.1002/ggge.20236 Geochemistry, Geophysics, Geosystems 14 Blackwell Publishing Ltd 3801-3820 School of Geography Environment and Earth Sciences, Victoria University of Wellington, PO Box 600, Wellington 6012, New Zealand; GNS Science, Lower Hutt, New Zealand; Department of Geology, University of Otago, Dunedin, New Zealand; School of Environment, University of Auckland, Auckland, New Zealand; Department of Geological Sciences, University of Canterbury, Christchurch, New Zealand; GNS Science, Dunedin, New Zealand 9 Earthquakes; Electric properties; Geophysics; Grinding (comminution); Plates (structural components); Principal component analysis; Rock drilling; Structural geology; Well logging, Alpine Faults; DFDP-1; Earthquake cycles; Fault zone structures; Wireline logging, Faulting, core analysis; deep drilling; earthquake rupture; fault zone; principal component analysis; seismicity; well logging, Alpine Fault Zone; New Zealand; South Island https://www.scopus.com/inward/record.uri?eid=2-s2.0-84886669141&doi=10.1002%2fggge.20236&partnerID=40&md5=cbea9975ec816be85207e401f54298cf cited By 47 J. Townend R. Sutherland V.G. Toy J.D. Eccles C. Boulton S.C. Cox D. McNamara article Kliem201354 The 106m long composite profile from site 2 of ICDP expedition 5022 (PASADO) at Laguna Potrok Aike documents a distinct change in sedimentation patterns from pelagic sediments at the top to dominating mass movement deposits at its base. The main lithological units correspond to the Holocene, to the Lateglacial and to the last glacial period and can be interpreted as the result of distinct environmental variations. Overflow conditions might have been achieved during the last glacial period, while signs of desiccation are absent in the studied sediment record. Altogether, 58 radiocarbon dates were used to establish a consistent age-depth model by applying the mixed-effect regression procedure which results in a basal age of 51.2cal.kaBP. Radiocarbon dates show a considerable increase in scatter with depth which is related to the high amount of reworking. Validation of the obtained chronology was achieved with geomagnetic relative paleointensity data and tephra correlation. © 2012 Elsevier Ltd. Article 2013 10.1016/j.quascirev.2012.07.019 Quaternary Science Reviews 71 54 – 69 Argentina; Laguna Potrok Aike; Patagonia; Santa Cruz [Argentina]; Deposits; Geomagnetism; Salinity measurement; Sedimentology; Sediments; Argentina; Holocenes; ICDP-project PASADO; Lake level fluctuations; Late Pleistocene; Mass movement; Mixed-effect regression; Patagonia; climate variation; data set; geochronology; glacial environment; Holocene; lacustrine deposit; Last Glacial; lithology; mass movement; numerical model; radiocarbon dating; sedimentation; tephrochronology; Lithology https://www.scopus.com/inward/record.uri?eid=2-s2.0-84878896037&doi=10.1016%2fj.quascirev.2012.07.019&partnerID=40&md5=31e2d9a5847388acb98de7e7c4e735ff Cited by: 56 Pierre Kliem Dirk Enters Annette Hahn Christian Ohlendorf Agathe Lisé-Pronovost Guillaume St-Onge Stefan Wastegård Bernd Zolitschka article cp-9-1467-2013 Here we present a detailed multi-proxy record of the climate and environmental evolution at Lake El'gygytgyn, Far East Russian Arctic during the period 430-395 ka covering the marine isotope stage (MIS) 12/11 transition and the thermal maximum of super interglacial MIS 11c. The MIS 12/11 transition at Lake El'gygytgyn is characterized by initial warming followed by a cold reversal implying similarities to the last deglaciation. The thermal maximum of MIS 11c is characterized by full and remarkably stable interglacial conditions with mean temperatures of the warmest month (MTWM) ranging between ca. 10-15 C; annual precipitation (PANN) ranging between ca. 300-600 mm; strong in-lake productivity coinciding with dark coniferous forests in the catchment; annual disintegration of the lake ice cover; and full mixis of the water column. Such conditions persisted, according to our age model, for ca. 27 ± 8 kyr between ca. 425-398 ka. The Lake El'gygytgyn record closely resembles the climate pattern recorded in Lake Baikal (SE Siberia) sediments and Antarctic ice cores, implying interhemispheric climate connectivity during MIS 11c. © 2013. CC Attribution 3.0 License. 2013 English 18149324 10.5194/cp-9-1467-2013 Climate of the Past 9 1467-1479 Institute of Geology and Mineralogy, University of Cologne, Zülpicher Str. 49a, 50674 Köln, Germany; Institute of Geological Sciences and Oeschger Centre for Climate Change Research, University of Bern, Baltzerstr. 1+3, 3012, Bern, Switzerland; Department of Ecology and Environmental Science, Umeä University, 901 87 Umeä, Sweden; Department of Geosciences, University of Massachusetts, 611 North Pleasant Str., Amherst, MA 01003, United States; Palaeontology Branch, Institute of Geological Sciences, Free University Berlin, Malteserstr. 74-100 Haus, 12249 Berlin, Germany; Climate Impacts Research Centre (CIRC), Department of Ecology and Environmental Science, Umeä University, c/o Abisko Naturvetenskapliga Station, 981 07 Abisko, Sweden 4 climate modeling; climate variation; ice core; ice cover; interglacial; isotopic analysis; lake evolution, Chukchi; Elgygytgyn Lake; Russian Federation https://cp.copernicus.org/articles/9/1467/2013/ cited By 27 H. Vogel C. Meyer-Jacob M. Melles J. Brigham-Grette A. A. Andreev V. Wennrich P. E. Tarasov P. Rosen article Roy2013 2013 Feb 01 0974-6889 10.1007/s12594-013-0034-6 Journal of the Geological Society of India 81 289-290 2 https://doi.org/10.1007/s12594-013-0034-6 Sukanta Roy N. P. Rao Vyasulu V. Akkiraju Deepjyoti Goswami Mrinal Sen B. K. Bansal Shailesh Nayak article Puchtel201363 Article 2013 10.1016/j.gca.2013.01.016 Geochimica et Cosmochimica Acta 108 63 – 90 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84874454444&doi=10.1016%2fj.gca.2013.01.016&partnerID=40&md5=eaafdc482d8f7e610dac208b843bebcf Cited by: 119 I.S. Puchtel J. Blichert-Toft M. Touboul R.J. Walker G.R. Byerly E.G. Nisbet C.R. Anhaeusser article Vuillemin2013119 Living microorganisms inhabit every environment of the biosphere but only in the last decades their importance governing biochemical cycles in deep sediments has been widely recognized. Most investigations have been accomplished in the marine realm whereas there is a clear paucity of comparable studies in lacustrine sediments. One of the main challenges is to define geomicrobiological proxies that can be used to identify different microbial signals in the sediments. Laguna Potrok Aike, a maar lake located in Southeastern Patagonia, has an annually not stratifying cold water column with temperatures ranging between 4 and 10°C, and most probably an anoxic water/sediment interface. These unusual features make it a peculiar and interesting site for geomicrobiological studies. Living microbial activity within the sediments was inspected by the first time in a sedimentary core retrieved during an ICDP-sponsored drilling operation. The main goals to study this cold subsaline environment were to characterize the living microbial consortium; to detect early diagenetic signals triggered by active microbes; and to investigate plausible links between climate and microbial populations. Results from a meter long gravity core suggest that microbial activity in lacustrine sediments can be sustained deeper than previously thought due to their adaptation to both changing temperature and oxygen availability. A multi-proxy study of the same core allowed defining past water column conditions and further microbial reworking of the organic fraction within the sediments. Methane content shows a gradual increase with depth as a result of the fermentation of methylated substrates, first methanogenic pathway to take place in the shallow subsurface of freshwater and subsaline environments. Statistical analyses of DGGE microbial diversity profiles indicate four clusters for Bacteria reflecting layered communities linked to the oxidant type whereas three clusters characterize Archaea communities that can be linked to both denitrifiers and methanogens. Independent sedimentary and biological proxies suggest that organic matter production and/or preservation have been lower during the Medieval Climate Anomaly (MCA) coinciding with a low microbial colonization of the sediments. Conversely, a reversed trend with higher organic matter content and substantial microbial activity characterizes the sediments deposited during the Little Ice Age (LIA). Thus, the initial sediments deposited during distinctive time intervals under contrasting environmental conditions have to be taken into account to understand their impact on the development of microbial communities throughout the sediments and their further imprint on early diagenetic signals. © 2012 Elsevier Ltd. Article 2013 10.1016/j.quascirev.2012.04.011 Quaternary Science Reviews 71 119 – 130 Argentina; Laguna Potrok Aike; Patagonia; Santa Cruz [Argentina]; Bacteria (microorganisms); Bacteria; Biogeochemistry; Biological materials; Deposits; Lakes; Methanation; Methane; Organic compounds; Sedimentology; DGGE; Early diagenesis; Laguna potrok aike; LIA; MCA; Methane production; Microbial activities; PASADO; Patagonia; Subsaline; bacterium; biosphere; colonization; community structure; environmental conditions; fermentation; lacustrine deposit; Little Ice Age; maar; methane; microorganism; organic matter; oxygen; population structure; salinity; sediment core; species diversity; temperature effect; water column; Sediments https://www.scopus.com/inward/record.uri?eid=2-s2.0-84878949027&doi=10.1016%2fj.quascirev.2012.04.011&partnerID=40&md5=8ea1f2d2d5d5a7fa34d4c829bbeefa11 Cited by: 28 Aurèle Vuillemin Daniel Ariztegui article Gan2013345 Lake sediments commonly contain laminations and the occurrence and quantitative attributes of these microstrata contain signals of their depositional environment, limnological conditions, and past climate. However, the identification and measurement of laminae and their attributes remains a largely semi-manual process that is tedious, labor intensive, but subject to human error. Here, we present a method to automatically measure and accurately extract lamina properties from sediment core images. This method is comprised of four major components: (1) image enhancement that includes noise reduction and contrast enhancement to improve signal-to-background ratio and resolution of laminae; (2) identification of 1-D laminae for a user-chosen area in an image; (3) laminae connectivity analyses on the 1-D laminae to obtain a lamina stratigraphy; and (4) extraction and retrieval of the primary and derived lamination stratigraphic data. Sediment core images from Lake Hitchcock and Lake Bosumtwi were used for algorithm development and testing. Our experiments show a complete match between laminae produced by the software and manual process for images from Lake Hitchcock. Quantitative comparisons reveal an insignificant discrepancy in the number of laminae identified automatically by the software and manually by researchers, and in over 90% of the cases the position mismatch of individual laminae is less than one pixel between the software and the manual method for the experimental images from Lake Bosumtwi. © 2012 Elsevier Ltd. Article 2013 English 00983004 10.1016/j.cageo.2012.10.016 Computers and Geosciences 52 345 – 355 Ashanti; Ghana; Lake Bosumtwi; Algorithms; Image matching; Lakes; Laminating; Sedimentology; Sediments; Stratigraphy; 2-D laminae; Algorithm development; Best fit algorithm; Connectivity analysis; Contrast Enhancement; Depositional environment; Human errors; Image processing - methods; Labor intensive; Lake sediments; Lamina properties; Limnological conditions; Manual methods; Manual process; Paleoclimates; Quantitative attributes; Quantitative comparison; Sediment core; Signal-to-background ratio; Stratigraphic data; algorithm; identification method; image analysis; image processing; lacustrine deposit; paleoclimate; quantitative analysis; sediment core; Image processing https://www.scopus.com/inward/record.uri?eid=2-s2.0-84871527713&doi=10.1016%2fj.cageo.2012.10.016&partnerID=40&md5=e95ac178abf92a6081b439135c2de02c Cited by: 2 Stoney Q. Gan Christopher A. Scholz article cp-9-1309-2013 2013 10.5194/cp-9-1309-2013 Climate of the Past 9 1309-1319 3 https://cp.copernicus.org/articles/9/1309/2013/ J. A. Snyder M. V. Cherepanova A. Bryan article brasier2013earth As part of the International Continental Scientific Drilling Program's Fennoscandian Arctic Russia-Drilling Early Earth Project (ICDP FAR-DEEP), Palaeoproterozoic diamictic and associated rocks were targeted and recovered in Hole 3A on the Kola Peninsula of NW Russia. In addition to the diamictites, carbonate sedimentary rocks and volcanic ash layers (all metamorphosed to greenschist grade) were encountered. Sedimentology and geochemistry suggest deposition of the diamictites in an open-marine aragonite-precipitating environment. Sampling of the core and of outcrops from the same geographical area yielded a number of zircons for analyses, the majority of which were inherited. However a tuff at 20.01m core depth yielded zircons dated at 2434±1.2Ma (±6.6Myr including decay constant uncertainties) that we interpret as a magmatic age. These data, combined with dates from underlying intrusions, indicate deposition of the Polisarka Sedimentary Formation diamictites and underlying carbonates during an interval of time from ca. 2430 to 2440Ma. The carbonate rocks, which likely originally included aragonitic limestones, were deposited mostly in a deep-water setting (i.e. at least below storm wave base) and occur below the diamictite. They record two inorganic carbon δ13C excursions, from values of ca. 0‰ to minima of ca. -5.4‰, as the contact with the overlying diamictite is approached. The older (stratigraphically lower) excursion occurs about 9m below the base of the diamictic units and the younger one at 1m below. Throughout that interval, Mg/Ca ratios correlate strongly with δ13C (n=38, r=0.85), and combined with petrographic observations, this indicates that the first (stratigraphically lower) excursion was modified by secondary alteration and the second is recorded in resedimented dolostone clasts. It is tempting to speculate that these dolostone clasts were deposited in penecontemporaneous shallow-marine waters, and that their low δ13C values might reflect input of oxidised atmospheric methane to the ocean surface (and therefore the cause of the glaciation); the dolostones were subsequently resedimented into the deeper marine settings. However this must be left as a hypothesis to be tested when further age-constrained contemporaneous pre-glacial carbonate sections are found. © 2013 Elsevier B.V. 2013 English 03019268 10.1016/j.precamres.2013.06.007 Precambrian Research 235 Elsevier 278--294 Faculty of Earth and Life Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081HV Amsterdam, Netherlands; NERC Isotope Geosciences Laboratory, British Geological Survey, Environmental Science Centre, Keyworth, Nottingham NG12 5GG, United Kingdom; Geological Survey of Norway, Postboks 6315 Slupen, NO-7491 Trondheim, Norway; Centre for Geobiology, University of Bergen, Postboks 7803, NO-5020 Bergen, Norway; Department of Earth and Environmental Sciences, University of St Andrews, Scotland, St Andrews KY16 9AL, United Kingdom; Scottish Universities Environmental Research Centre, Rankine Avenue, East Kilbride, Scotland G75 0QF, United Kingdom; GNS Science, Private Bag 1930, Dunedin, New Zealand aragonite; carbon isotope; carbonate rock; deposition; diamictite; dolostone; geochemistry; geochronology; glaciation; inorganic carbon; methane; outcrop; oxidation; Proterozoic; sedimentology; tuff; volcanic ash, Kola Peninsula; Murmansk [Russian Federation]; Russian Federation https://www.scopus.com/inward/record.uri?eid=2-s2.0-84881086634&doi=10.1016%2fj.precamres.2013.06.007&partnerID=40&md5=5a00be1681b57f1df92ef8f5ca6e7291 cited By 27 AT Brasier AP Martin VA Melezhik AR Prave DJ Condon AE Fallick article Dahm201393 2013 English 18168957 10.5194/sd-16-93-2013 Scientific Drilling 93-99 GFZ German Research Centre for Geosciences, Telegrafenberg, 14473 Potsdam, Germany; Institute of Geophysics, Academy of Science, 141 31 Prague, Czech Republic; Faculty of Science, Charles University in Prague, Albertov 6, 128 43, Prague, Czech Republic; Institute of Geophysics and Geoinformatics, TU Bergakademie Freiberg, 09599 Freiberg, Germany; Institut für Geophysik und Geologie, Universität Leipzig, Talstraße 35, 04103 Leipzig, Germany; Institute of Earth and Environmental Sciences, University of Potsdam, Karl-Liebknecht-Str. 24, 14476 Golm, Germany 16 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84892843755&doi=10.5194%2fsd-16-93-2013&partnerID=40&md5=2f27bf68246038e0ed55bbd32fbdcaef cited By 17 T. Dahm P. Hrubcová T. Fischer J. Horálek M. Korn D. Wagner article Koeberl20131108 The El'gygytgyn impact structure in Chukutka, Arctic Russia, is the only impact crater currently known on Earth that was formed in mostly acid volcanic rocks (mainly of rhyolitic, with some andesitic and dacitic, compositions). In addition, because of its depth, it has provided an excellent sediment trap that records paleoclimatic information for the 3.6 Myr since its formation. For these two main reasons, because of the importance for impact and paleoclimate research, El'gygytgyn was the subject of an International Continental Scientific Drilling Program (ICDP) drilling project in 2009. During this project, which, due to its logistical and financial challenges, took almost a decade to come to fruition, a total of 642.3 m of drill core was recovered at two sites, from four holes. The obtained material included sedimentary and impactite rocks. In terms of impactites, which were recovered from 316.08 to 517.30 m depth below lake bottom (mblb), three main parts of that core segment were identified: from 316 to 390 mblb polymict lithic impact breccia, mostly suevite, with volcanic and impact melt clasts that locally contain shocked minerals, in a fine-grained clastic matrix; from 385 to 423 mblb, a brecciated sequence of volcanic rocks including both felsic and mafic (basalt) members; and from 423 to 517 mblb, a greenish rhyodacitic ignimbrite (mostly monomict breccia). The uppermost impactite (316-328 mblb) contains lacustrine sediment mixed with impact-affected components. Over the whole length of the impactite core, the abundance of shock features decreases rapidly from the top to the bottom of the studied core section. The distinction between original volcanic melt fragments and those that formed later as the result of the impact event posed major problems in the study of these rocks. The sequence that contains fairly unambiguous evidence of impact melt (which is not very abundant anyway, usually less than a few volume%) is only about 75 m thick. The reason for this rather thin fallback impactite sequence may be the location of the drill core on an elevated part of the central uplift. A general lack of large coherent melt bodies is evident, similar to that found at the similarly sized Bosumtwi impact crater in Ghana that, however, was formed in a target composed of a thin layer of sediment above crystalline rocks. © The Meteoritical Society, 2013. 2013 English 10869379 10.1111/maps.12146 Meteoritics and Planetary Science 48 1108-1129 Department of Lithospheric Research, University of Vienna, Althanstrasse 14, Vienna, A-1090, Austria; Natural History Museum, Burgring 7, Vienna, A-1010, Austria; Museum für Naturkunde, Invalidenstrasse 43, Berlin, 10115, Germany; Humboldt-Universität zu Berlin, Unter den Linden 6, Berlin, 10099, Germany; Department of Geosciences, University of Massachusetts, Amherst, MA, 01003, United States; Institute of Geology and Mineralogy, University of Cologne, Zuelpicher Strasse 49a, Cologne, D-50674, Germany; North-East Interdisciplinary Scientific Research Institute, Far East Branch - Russian Academy of Sciences, 16 Portovaya St., Magadan, 685000, Russian Federation 7 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84880162253&doi=10.1111%2fmaps.12146&partnerID=40&md5=810b03c9413055d114500811ff12bf73 cited By 28 C. Koeberl L. Pittarello W.U. Reimold U. Raschke J. Brigham-Grette M. Melles P. Minyuk conference Podgorney2013191 The geologic characteristics and evolution of the Eastern Snake River Plain are consistent with transfer of large amounts of magma advected heat at mid- to upper-crustal levels. We speculate that some of this heat is stored below surficial basalt lavas, within underlying dense, hydrothermally altered rhyolites that infill large nested calderas. Cryptic hydrothermal systems may occur within caldera-related fracture systems, or megabreccias near caldera collapse scarps. Blind hot zones are also possible below young chemically evolved volcanoes on the ESRP. Other factors in addition to high temperatures and high heat flow that support EGS development are also prevalent on the ESRP. A number of deep exploration wells exist, and hundreds groundwater wells provide additional information on the character and makeup of the subsurface. The abundant cold groundwater resource can provide a significant heat sink for power generation, and also provide working fluid and makeup water as necessary. Regional stress and earthquake data suggest that the Plain is extensional to isotropic and "quiet". The seismic risks of the eastern Snake River Plain have been extensively investigated because of the nuclear facilities at Idaho National Laboratory. The epicenter of the 1983 (magnitude 7.3) Borah earthquake was located about 100km (70 miles) from INL's nuclear facilities, but no significant damage occurred. This is attributed to the alternating layers of hard basalt and soft sediment that lie beneath the Snake River Plain. This attenuation reduces the seismic risk from natural and induced seismic occurrences. Additional studies are currently underway to better understand the EGS potential for the eastern SRP. These include GIS and VSRP analysis of existing data, new geotechnical and geomechanical analysis of core samples, geochemical studies of water-rock interaction, and numerical modeling studies of fracturing, fluid flow, and heat recovery. 2013 English 9781629932859 01935933 Transactions - Geothermal Resources Council 37 191-197 Idaho National Laboratory, United States; Idaho State University, United States; Oklahoma University, United States; Idaho Geological Survey, United States; Energy and Geoscience Institute, University of Utah, United States; University of Idaho, United States; Washington State University, United States PART 1 Alternating layers; Deep exploration wells; Enhanced geothermal systems; Geologic characteristics; Hydrothermal system; Idaho national laboratories; Snake river plains; Water rock interactions, Basalt; Geothermal fields; Geothermal wells; Groundwater; Groundwater resources; Heat transfer; Models; Nuclear energy; Rivers; Waste heat, Earthquakes https://www.scopus.com/inward/record.uri?eid=2-s2.0-84897654221&partnerID=40&md5=5407bcadd09ab11b2c37fc49af91b9de cited By 3 R. Podgorney M. McCurry T. Wood T. McLing A. Ghassemi J. Welhan G. Mines M. Plummer J. Moore J. Fairley R. Wood article Zolitschka20131 In this introductory paper we summarize the history and achievements of the Potrok Aike maar lake Sediment Archive Drilling prOject (PASADO), an interdisciplinary project embedded in the International Continental Scientific Drilling Program (ICDP). The stringent multiproxy approach adopted in this research combined with radiocarbon and luminescence dating provided the opportunity to synthesize a large body of hydrologically relevant data from Laguna Potrok Aike (southern Patagonia, Argentina). At this site, lake level was high from 51ka until the early Holocene when the Southern Hemisphere Westerlies (SHW) were located further to the north. At 9.3kacal.BP the SHW moved southward and over the latitude of the study area (52°S) causing a pronounced negative water balance with a lake level decrease of more than 50m. Two millennia later, the SHW diminished in intensity and lake level rose to a subsequent maximum during the Little Ice Age. Since the 20th century, a strengthening of the SHW increased the evaporative stress resulting in a more negative water balance. A comparison of our data with other hydrological fluctuations at a regional scale in south-eastern Patagonia, provides new insights and also calls for better chronologies and high-resolution records of climate variability. © 2012 Elsevier Ltd. Article 2013 10.1016/j.quascirev.2012.11.024 Quaternary Science Reviews 71 1 – 12 Argentina; Laguna Potrok Aike; Santa Cruz [Argentina]; Climatology; Sedimentology; Argentina; Holocenes; ICDP; Lake levels; Last glacial; Patagonia; Southern Hemispheric Westerlies; Water balance; Holocene; interdisciplinary approach; lacustrine deposit; luminescence dating; maar; radiocarbon dating; Southern Hemisphere; twentieth century; water budget; Lakes https://www.scopus.com/inward/record.uri?eid=2-s2.0-84878907739&doi=10.1016%2fj.quascirev.2012.11.024&partnerID=40&md5=32b2de9829b840e05937afa6d2c3066f Cited by: 61 B. Zolitschka F. Anselmetti D. Ariztegui H. Corbella P. Francus A. Lücke N.I. Maidana C. Ohlendorf F. Schäbitz S. Wastegård article Wang20131 2013 English 00310182 10.1016/j.palaeo.2013.05.006 Palaeogeography, Palaeoclimatology, Palaeoecology 385 1-5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84879867752&doi=10.1016%2fj.palaeo.2013.05.006&partnerID=40&md5=9a8cd9799d60f80dbc73d10682f166ce cited By 29 C. Wang article Sanford2013252 High-salinity groundwater more than 1,000 metres deep in the Atlantic coastal plain of the USA has been documented in several locations, most recently within the 35-million-year-old Chesapeake Bay impact crater. Suggestions for the origin of increased salinity in the crater have included evaporite dissolution, osmosis and evaporation from heating associated with the bolide impact. Here we present chemical, isotopic and physical evidence that together indicate that groundwater in the Chesapeake crater is remnant Early Cretaceous North Atlantic (ECNA) sea water. We find that the sea water is probably 100-145 million years old and that it has an average salinity of about 70 per mil, which is twice that of modern sea water and consistent with the nearly closed ECNA basin. Previous evidence for temperature and salinity levels of ancient oceans have been estimated indirectly from geochemical, isotopic and palaeontological analyses of solid materials in deep sediment cores. In contrast, our study identifies ancient sea water in situ and provides a direct estimate of its age and salinity. Moreover, we suggest that it is likely that remnants of ECNA sea water persist in deep sediments at many locations along the Atlantic margin. © 2013 Macmillan Publishers Limited. All rights reserved. 2013 English 00280836 10.1038/nature12714 Nature 503 252-256 US Geological Survey, Mail Stop 431, Reston, VA 20192, United States; US Geological Survey, Federal Center, Box 25046, Denver, CO 80225, United States; US Geological Survey, McKelvey Building 15, Mail Stop 420, 345 Middlefield Road, Menlo Park, CA 94025, United States 7475 ground water; sea water, bolide; coastal plain; crater; Cretaceous; dissolution; evaporite; groundwater; impact; osmosis; salinity; seawater, article; chemical analysis; coastal plain; dissolution; evaporation; heating; Lower Cretaceous; osmosis; priority journal; salinity; sediment; temperature, Atlantic Ocean; Bays; Geological Phenomena; Groundwater; Salinity; Seawater, Atlantic Coastal Plain; Chesapeake Bay; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-84887602867&doi=10.1038%2fnature12714&partnerID=40&md5=f94cc2c10395f8dcbe11c07cfab49b8f cited By 14 W.E. Sanford M.W. Doughten T.B. Coplen A.G. Hunt T.D. Bullen book Lambert20131 2013 10.1002/9781118622612.ch1 Materials under Extreme Loadings: Application to Penetration and Impact 1-43 Sciences and Applications, Applied Research under Contract, Bordeaux Merignac, France; CEA Le Ripault, Monts, France https://www.scopus.com/inward/record.uri?eid=2-s2.0-84886345132&doi=10.1002%2f9781118622612.ch1&partnerID=40&md5=585567a7d25d6cc28cec279801df43e3 cited By 0 P. Lambert H. Trumel article Lepland2013493 2013 English 9783642296581 18634621 10.1007/978-3-642-29659-8_1 Frontiers in Earth Sciences 7 Frontiers 493-502 Geological Survey of Norway, Postboks 6315 Sluppen, Trondheim NO-7491, Norway https://www.scopus.com/inward/record.uri?eid=2-s2.0-84871054257&doi=10.1007%2f978-3-642-29659-8_1&partnerID=40&md5=0313de5e5e42fd5e2d25237e44208348 cited By 2 A. Lepland M. Mesli R. Conze K. Fabian A.E. Fallick L.R. Kump article Pavlov20131 Within the past few decades Eunotia (Bacillariophyceae) has been confirmed as one of the most species rich diatom genera. The remarkable diversity of this genus has been well documented for the tropical region of South America, and its wide distribution comprehensively demonstrated for North America and Canada, Europe, East and Southeast Asia, as well as the Subantarctic region. Till present day only twenty eight taxa of Eunotia have been reported for Macedonia, mainly from the various aquatic habitats of different mountains. The main focus of the present study is the diversity, taxonomy and general distribution of taxa belonging to Eunotia in Macedonian mountain regions. The area investigated covers most of the mountains in the western, south-western, southern, central and eastern part. In total 53 taxa have been observed, among which six are described as new species (Eunotia atomus, E. fabaeformis, E. mariovensis, E. pseudominor, E. scardica and E. stojanovskii). The morphological features, as observed by light microscopy (LM), are comprehensively described for each taxon. The ultrastructure of the valve, as observed by scanning electron microscopy (SEM), is additionally described for most of the taxa. The general distributional pattern, locality, altitude and substrate preference, for every taxon is also included. The distinctive characters between similar taxa are discussed and taxonomical notes are as well provided. © 2013 Magnolia Press. Article 2013 English 11793163 10.11646/phytotaxa.86.1.1 Phytotaxa 86 1 – 117 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84878117884&doi=10.11646%2fphytotaxa.86.1.1&partnerID=40&md5=8ecd42ae5e956875899a19baffce3e81 Cited by: 32 Aleksandar Pavlov Zlatko Levkov article Shervais201336 HOTSPOT is an international collaborative effort to understand the volcanic history of the Snake River Plain (SRP). The SRP overlies a thermal anomaly, the Yellowstone-Snake River hotspot, that is thought to represent a deep-seated mantle plume under North America. The primary goal of this project is to document the volcanic and stratigraphic history of the SRP, which represents the surface expression of this hotspot, and to understand how it affected the evolution of continental crust and mantle. An additional goal is to evaluate the geothermal potential of southern Idaho. Project HOTSPOT has completed three drill holes. (1) The Kimama site is located along the central volcanic axis of the SRP; our goal here was to sample a long-term record of basaltic volcanism in the wake of the SRP hotspot. (2) The Kimberly site is located near the margin of the plain; our goal here was to sample a record of high-temperature rhyolite volcanism associated with the underlying plume. This site was chosen to form a nominally continuous record of volcanism when paired with the Kimama site. (3) The Mountain Home site is located in the western plain; our goal here was to sample the Pliocene-Pleistocene transition in lake sediments at this site and to sample older basalts that underlie the sediments. We report here on our initial results for each site, and on some of the geophysical logging studies carried out as part of this project. Article 2013 English 18168957 10.5194/sd-15-36-2013 Scientific Drilling Copernicus GmbH 36 – 45 Department of Geology, Utah State University, 4505 Old Main Hill, Logan, UT 84322-4505, United States; Department of Physics, CCIS 3-091, University of Alberta, Edmonton, AB, T6G 2E1, Canada; DOSECC, Inc., 2075 Pioneer Road, Suite B, Salt Lake City, UT 84104-4231, United States; Department of Geological Sciences, Brigham Young University, Provo, UT 84602, United States; U.S. Geological Survey, Central Mineral and Environmental Resources Science Center, Denver Federal Center, Box 25046, MS-973, Denver, CO 80225, United States; Center for Geophysical Investigation of the Shallow Subsurface, Boise State University, 1910 University Drive, Boise, ID 83725-1536, United States; Huffington Department of Earth Sciences, Southern Methodist University, P.O. Box 750395, Dallas, TX 75275-0395, United States; U.S. Geological Survey, 345 Middlefield Road, Menlo Park, CA 94025-3591, United States; Department of Earth and Ocean Sciences, University of South Carolina, Columbia, SC 29208, United States 15 Distributed computer systems; Infill drilling; Stratigraphy; Volcanoes; Basaltic volcanism; Continental crusts; Geophysical logging; Geothermal potential; Scientific drilling; Snake river plains; Surface expression; Thermal anomalies; Rivers https://www.scopus.com/inward/record.uri?eid=2-s2.0-84877816432&doi=10.5194%2fsd-15-36-2013&partnerID=40&md5=c3e1ecc424b53224ea759b52297a1d93 Cited by: 30; All Open Access, Gold Open Access, Green Open Access John W. Shervais Dennis Nielson James P. Evans Eric H. Christiansen Lisa Morgan W.C. Pat Shanks Alexander A. Prokopenko Thomas Lachmar Lee M. Liberty David D. Blackwell Jonathan M. Glen Duane Champion Katherine E. Potter James A. Kessler conference Sakiyama20132797 Temperature profiles and their transient behaviors obtained using a distributed temperature sensing (DTS) system were measured while monitoring wellbore fluid levels during a methane hydrate production test. The temperature data were obtained in 2008 as part of the JOGMECTNRCan/Aurora Mallik 2007 2008 Gas Hydrate Production Research Well Program. Methane hydrate is known to be stabilized under low-temperature and high-pressure conditions. In the Gas Hydrate Production Research Well Program, a depressurization method using an electric submergible pump (ESP) was employed to dissociate the hydrate in the reservoir. For recovering the produced gas and fluid without resynthesizing the hydrate after the dissociation, it was essential that the temperature of the produced fluids flowing up the tubing be controlled. According to our numerical temperature simulation, the annulus fluid level around the tubing is one of important factors that govern the tubing fluid temperature during the methane hydrate production. If the annulus fluid level is high, the tubing fluid temperature becomes so low that methane hydrate can potentially be formed inside the tubing; thus, understanding fluid levels during methane hydrate production is important for flow assurance as well as bottomhole pressure control. The conventional method for estimating fluid levels in a wellbore employs an acoustic wave reflection technique; however, the uracy of the survey is subjected to assumption of an acoustic velocity which depends on pressure, temperature, and gas types. On the other hand, estimating fluid levels with a DTS temperature profile is thought to be a more direct method. Although it is not widely known, several papers indicate that the feasibility of estimating fluid levels with the DTS system when the fluid level is static. In this paper, we demonstrate the feasibility of estimating dynamic fluid levels using a DTS system. The dynamic trend in estimated fluid levels with the DTS system shows qualitatively good agreement to that estimated with the pressure on the completion assembly and the pressure at the casinghead. The difference in fluid levels between the DTS temperature-based and the pressure-based methods quantitatively explains a void traction in the two-phase flow of the fluid and the gas. The analysis presented in this paper is based on field data collected during methane hydrate production, but it is potentially applicable to any conventional production scheme that employs artificial lift. Copyright © (2013) by the Society of Petroleum Engineers. 2013 English 9781627481762 Society of Petroleum Engineers - International Petroleum Technology Conference 2013, IPTC 2013: Challenging Technology and Economic Limits to Meet the Global Energy Demand 4 2797-2808 Schlumberger, United States; Japan Oil Gas, and Metals National Corporation, Japan; Natural Resources Canada, Canada Depressurization methods; Distributed temperature sensing systems; Gas-hydrate production; High-pressure condition; Methane hydrate productions; Pressure-based method; Temperature profiles; Temperature simulations, Acoustic wave velocity; Acoustic wave velocity measurement; Bottom hole pressure; Energy management; Estimation; Gases; Hydration; Low temperature production; Methane; Oil field equipment; Petroleum engineering; Temperature control; Temperature sensors; Tubing, Gas hydrates https://www.scopus.com/inward/record.uri?eid=2-s2.0-84883376296&partnerID=40&md5=2786ce646bb5d616656121fe6edbe4f4 cited By 6 N. Sakiyama K. Fujii V. Pimenov A. Parshin K. Yamamoto J.F. Write article Zagórski2013452 Unconventional hydrocarbon resources in last years draw the attention of petroleum geologists. Significant position take the gas hydrates, first of all due to occurrences in many regions of the world and the size of the potential resources. These accumulations are localized in Arctic regions with permafrost as well as offshore. First gas hydrate discovery occurred in Siberian gas field Messoyakha in permafrost zone and similar accumulations were found in Alaska. Offshore occurrences are located mainly on continental slope. Drillings and samples from permafrost and seabed provided vast amount of data concerned conditions of gas hydrates formation and concentration and allow to better constrain the volume of hydrate-bearing sediments and their gas yield. Resources of hydrocarbons contained in gas hydrate deposits represent a vast energy source potential. Still essential problem is to elaborate efficient commercial production technology. So far positive developments regard only laboratory or semi-commercial scale. 2013 Polish 00332151 Przeglad Geologiczny 61 Polish Geological Institute 452-459 not available, Ul. Czerniakowska 28a, m. 4, 00-714 Warszawa, Poland 8 continental slope; fossil fuel; gas field; gas hydrate; hydrocarbon resource; methane; mud volcano; permafrost; submarine landslide, Alaska; Arctic; China; Kuparuk River; Nankai; Siberia; Tianjin; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-84884824329&partnerID=40&md5=8577ea9ae29f04cba7013830cf4a63e3 cited By 2 J. Zagórski article Xiao201362 Major ions, isotopic ratios of strontium (87Sr/86Sr), hydrogen (δD) and oxygen (δ18O) of groundwater samples were analyzed to decipher spatial variation, controlling factors, solute sources, and the rechargesource of shallow groundwaters within the Lake Qinghai catchment. Shallow groundwaters in this area are slightly alkaline, with 97% being fresh water of good quality, though there are high concentrations of nitrate and sulfide in Buha and lakeside groundwaters. Most of the shallow groundwatersare of the Ca2+-HCO3- type, whereas part of groundwaters surrounding the lake (LS) belongs to the Na+-Cl- type as lake water (QHL). Groundwater geochemistry is controlled by regional lithological association, ion exchange, and mineral precipitation. The dissolved Sr concentrations and 87Sr/86Sr ratios vary from 1.0 to 15.6μmol/L, and from 0.709859 to 0.715779, respectively. The first quantitative calculation in groundwater using a forward model shows that 40% of dissolved Sr is from carbonate weathering, 33% from evaporite dissolution, 17% from silicate weathering, and the remainder from atmospheric input for the whole catchment. Carbonate weathering dominates groundwater geochemistry in Shaliu (SL), Hargai (HG) and Buha (BH) samples, while evaporite dissolution dominates LS and Daotang (DT) samples. δD and δ18O data show that rain water is the major recharge source of both river water and shallow groundwater within the Lake Qinghai catchment. Qinghai Lake water is characterized by Buha-type water, but its Sr geochemistry is different from the shallow groundwater due to carbonate precipitation. Although shallow groundwater contributes ~5% of the dissolved Sr to the QHL, groundwater must be taken into account when the chemistry and budget of lake water are characterized. © 2013 Elsevier Ltd and INQUA. Article 2013 English 10406182 10.1016/j.quaint.2013.05.033 Quaternary International 313-314 62 – 73 China; Qinghai; Qinghai Lake; Qinghai-Xizang Plateau; carbonate; concentration (composition); groundwater; hydrochemistry; hydrogen isotope; ion exchange; isotopic composition; isotopic ratio; lake water; lithology; nitrate; oxygen isotope; rainwater; recharge; river water; solute; spatial variation; strontium isotope; sulfide; weathering https://www.scopus.com/inward/record.uri?eid=2-s2.0-84886722513&doi=10.1016%2fj.quaint.2013.05.033&partnerID=40&md5=21ae38872b6aef2119d5bf175149ef95 Cited by: 18 Jun Xiao Zhangdong Jin Fei Zhang article Jean20131319 The temporal and magmatic evolution of central Snake River Plain (SRP; Idaho, USA) olivine tholeiites erupted within the past 4 m.y. is evaluated here. This investigation correlates and merges both geochemical and paleomagnetic measurements to constrain the volcanic history recovered from the 340 m Regional Aquifer Systems Analysis (RASA) test well located near Wendell, Idaho. Only a handful of studies have accomplished this task of shedding light on the chemical stratigraphy of the SRP and the petrogenesis of basalts with depth, and therefore through time. Paleomagnetic relationships suggest that time breaks between individual lava flows represent a few years to decades, time breaks between flow groups represent at least a couple of hundred years or possibly much longer, while significant hiatuses in volcanism, revealed by thick sediment packages or polarity reversals (both are evidenced in this well), are inferred to last thousands to tens of thousands of years. Major element geochemistry from 52 basaltic lava flows demonstrates near primitive compositions (i.e., ~10 wt% MgO) and tholeiitic iron enrichment trends, similar to lavas from the eastern SRP. Trace element concentrations are similar to those of ocean island basalts, with enriched Ba and Pb, and light rare earth element (REE)/heavy REE ratios similar to those of many Neogene volcanics of the western Cordillera. When combined, we identify a total of 11 flow groups, which we also classify as fractionation or recharge on the basis of decreasing or increasing MgO weight percent with depth. Taking into consideration these trends, we review the potential recharge, fractionation, and assimilation processes that characterize much of SRP olivine tholeiite, and conclude that assimilation, in combination with fractional crystallization, is the dominant petrogenesis for the basalts in the central SRP. Although fractionation of Wendell parent magmas was accompanied by assimilation of crustal material, this could not have been assimilation of ancient cratonic crust. The geochemical cycles observed in this well are inferred to represent fractionation and recharge of basaltic magma from a series of sill-like layered mafic intrusions located in the middle crust, similar to what has been proposed for the processes that control the eruptive history of basalts in the eastern SRP. © 2013 Geological Society of America. 2013 English 1553040X 10.1130/GES00914.1 Geosphere 9 1319-1335 Department of Geology, Northern Illinois University, Davis Hall 312, DeKalb, Illinois 60115, United States; Institutfur Mineralogie, Leibniz Universitaet Hannover, Callinstr. 3, 30167 Hannover, Germany; Department of Geology, Utah State University, 4505 Old Main Hill, Logan, Utah 84322-4505, United States; U.S. Geological Survey, 345 Middlefield Road, Menlo Park, California 94025, United States; Department of Geology, Centenary College, Shreveport, Louisiana 71134, United States 5 aquifer; basalt; concentration (composition); fractional crystallization; igneous geochemistry; igneous intrusion; lava flow; magma; ocean island basalt; paleomagnetism; petrogenesis; tholeiite; trace element; volcanism, Idaho; Snake River Plain; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-84885087820&doi=10.1130%2fGES00914.1&partnerID=40&md5=7c7a1e8aa211bd128655576c085b5db6 cited By 7 M.M. Jean J.W. Shervais D.E. Champion S.K. Vetter article Ehlmann2013329 Clays form on Earth by near-surface weathering, precipitation in water bodies within basins, hydrothermal alteration (volcanic- or impact-induced), diagenesis, metamorphism, and magmatic precipitation. Diverse clay minerals have been detected from orbital investigation of terrains on Mars and are globally distributed, indicating geographically widespread aqueous alteration. Clay assemblages within deep stratigraphic units in the Martian crust include Fe/Mg smectites, chlorites and higher temperature hydrated silicates. Sedimentary clay mineral assemblages include Fe/Mg smectites, kaolinite, and sulfate, carbonate, and chloride salts. Stratigraphic sequences with multiple clay-bearing units have an upper unit with Al-clays and a lower unit with Fe/Mg-clays. The typical restriction of clay minerals to the oldest, Noachian terrains indicates a distinctive set of processes involving water-rock interaction that was prevalent early in Mars history and may have profoundly influenced the evolution of Martian geochemical systems. Current analyses of orbital data have led to the proposition of multiple clay-formation mechanisms, varying in space and time in their relative importance. These include near-surface weathering, formation in ice-dominated near-surface groundwaters, and formation by subsurface hydrothermal fluids. Near-surface, open system formation of clays would lead to fractionation of Mars' crustal reservoir into an altered crustal reservoir and a sedimentary reservoir, potentially involving changes in the composition of Mars' atmosphere. In contrast, formation of clays in the subsurface by either aqueous alteration or magmatic cooling would result in comparatively little geochemical fractionation or interaction of Mars' atmospheric, crustal, and magmatic reservoirs, with the exception of long-term sequestration of water. Formation of clays within ice would have geochemical consequences intermediate between these endmembers. We outline the future analyses of orbital data, in situ measurements acquired within clay-bearing terrains, and analyses of Mars samples that are needed to more fully elucidate the mechanisms of martian clay formation and to determine the consequences for the geochemical evolution of the planet. © 2012 Springer Science+Business Media B.V. 2013 10.1007/s11214-012-9930-0 Space Science Reviews 174 329-364 Institut d'Astrophysique Spatiale, Université Paris-Sud, Orsay 91405, France; Division of Geological and Planetary Sciences, Jet Propulsion Laboratory, California Institute of Technology, Pasadena CA 91125, United States; IRAP, CNRS-Université Toulouse, 31400 Toulouse, France; Laboratoire Planétologie et Géodynamique de Nantes, CNRS, Université de Nantes, Nantes, France; Planetary Science Institute, Tucson AZ 85719, United States; Mineralogy, Natural History Museum, London, United Kingdom; Department of Earth and Space Sciences, Astrobiology Program, University of Washington, Seattle WA 98195, United States; School of Earth and Space Exploration, Arizona State University, Tempe AZ 85287, United States; Laboratoire IDES, UMR 8148, CNRS, 91405 Orsay, France; Astromaterials Research and Exploration Science, NASA Johnson Space Center, Houston TX 77058, United States; W.M. Keck Laboratory for Space and Planetary Simulation, Arkansas Center for Space and Planetary Science, University of Arkansas, Fayetteville AR 72701, United States 1-4 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84871780802&doi=10.1007%2fs11214-012-9930-0&partnerID=40&md5=83dddcf65a8769fed9d33ceaadfb85bc cited By 91 B.L. Ehlmann G. Berger N. Mangold J.R. Michalski D.C. Catling S.W. Ruff E. Chassefière P.B. Niles V. Chevrier F. Poulet book levkov2013diatoms 2013 Koeltz Scientific Books, Konigstein Z Levkov D Metzeltin A Pavlov article Reimold20131531 Suevite and melt breccia compositions in the boreholes Enkingen and Polsingen are compared with compositions of suevites from other Ries boreholes and surface locations and discussed in terms of implications for impact breccia genesis. No significant differences in average chemical compositions for the various drill cores or surface samples are noted. Compositions of suevite and melt breccia from southern and northeastern sectors of the Ries crater do not significantly differ. This is in stark contrast to the published variations between within-crater and out-of-crater suevites from northern and southern sectors of the Bosumtwi impact structure, Ghana. Locally occurring alteration overprint on drill cores-especially strong on the carbonate-impregnated suevite specimens of the Enkingen borehole-does affect the average compositions. Overall, the composition of the analyzed impact breccias from Ries are characterized by very little macroscopically or microscopically recognized sediment-clast component; the clast populations of suevite and impact melt breccia are dominated consistently by granitic and intermediate granitoid components. The Polsingen breccia is significantly enriched in a dioritic clast component. Overall, chemical compositions are of intermediate composition as well, with dioritic-granodioritic silica contents, and relatively small contributions from mafic target components. Selected suevite samples from the Enkingen core have elevated Ni, Co, Cr, and Ir contents compared with previously analyzed suevites from the Ries crater, which suggest a small meteoritic component. Platinum-group element (PGE) concentrations for some of the enriched samples indicate somewhat elevated concentrations and near-chondritic ratios of the most immobile PGE, consistent with an extraterrestrial contribution of 0.1-0.2% chondrite-equivalent. © The Meteoritical Society, 2013. 2013 10.1111/maps.12175 Meteoritics and Planetary Science 48 1531-1571 Museum für Naturkunde-Leibniz-Institut für Evolutions- und Biodiversitätsforschung, Invalidenstrasse 43, 10115 Berlin, Germany; Humboldt Universität zu Berlin, Unter den Linden 6, 10099 Berlin, Germany; School of Earth And Ocean Sciences, Cardiff University, Park Place, Cardiff CF10 3YE, United Kingdom; Department of Lithospheric Research, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria; Natural History Museum, Burgring 7, 1010 Vienna, Austria 9 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84884974822&doi=10.1111%2fmaps.12175&partnerID=40&md5=d6bbb5b03ab8c406f07f657d23a47dfc cited By 9 W.U. Reimold I. Mcdonald R.-T. Schmitt B. Hansen J. Jacob C. Koeberl article Konstantinou20131681 The Jim Sage volcanic suite (JSVS) exposed in the Jim Sage and Cotterel Mountains of southern Idaho (USA) consists of two volcanic members composed of ~240 km3 of Miocene rhyolite lavas separated by an interval of lacustrine sediments. It is capped by rheomorphic ignimbrite and as much as 100 m of basaltic lava fl ows probably derived from the central Snake River Plain (SRP) province to the north. The occurrence of volcanic vents in the JSVS links the lava fl ows to their local eruptive centers, while the adjacent Albion-Raft River-Grouse Creek metamorphic core complex exposes ~3000 km2 of once deep-seated rocks that offer constraints on the composition of the potential crustal sources of these rhyolites. U-Pb zircon ages from the rhyolite lavas of the JSVS range from 9.5 to 8.2 Ma. The Miocene basalt of the Cotterel Mountains has an 87Sr/86Sri composition of 0.7066-0.7075 and εNd(i) = -3.7, and the rhyolite lavas of the JSVS have 87Sr/86Sri = 0.7114-0.7135 and εNd(i) values that range from -6.7 to -7.1. Zircon from the rhyolites of the JSVS range in δ18Ozr (Vienna standard mean ocean water, VSMOW) from -0.5‰ to 5.7‰ and have εHf(i) values ranging from -0.8 to -6.8. Based on geochronology, whole-rock major elements, trace elements, isotopes (Sr and Nd), and in situ zircon O and Hf isotopic compositions, we infer that the JSVS is genetically related to the central SRP province. The eruption of the low-δ18O rhyolites of the JSVS, outside of the main topographic extent of the SRP province (without the large calderas inferred for the SRP rhyolites) implies that there might be an alternative mechanism for the formation of the low-δ18O signature other than the proposed assimilation of hydrothermally altered caldera blocks. One suggestion is that the north to south propagation of SRP-type low-δ18O rhyolitic melt along the Albion fault led to off-axis magmatism. Another possibility is that there was prior and widespread (across a region wider than the SRP) hydrothermal alteration of the crust related to its earlier magmatic and faulting history. The eruption of SRP-type lavas in the hanging wall of an evolving metamorphic core complex helps us outline the role of the SRP magmatic province in the extensional evolution of the northeastern Basin and Range. The lavas of the JSVS imply the addition of basalt, related to the SRP hotspot, to the crust beneath the Raft River Basin that provided a heat source for crustal melting and weakening of the deep crust; this led to a vertical component of crustal fl ow and doming during extension, after the eruption of the 9.5-8.2 Ma JSVS rhyolites. This younger than 8.2 Ma component of vertical motion during faulting of the Miocene stratifi ed sequence of the Raft River Basin and the rotation of the Albion fault to shallower angles collectively resulted in the subhorizontal detachment structure imaged seismically beneath the Raft River Basin. © 2013 Geological Society of America. 2013 English 1553040X 10.1130/GES00948.1 Geosphere 9 1681-1703 Department of Geological and Environmental Sciences, Stanford University, Stanford, CA 94305, United States; Department of Geoscience, University of Wisconsin, 1215 W. Dayton Street, Madison, WI 53706, United States; School of the Environment, Washington State University, WA 99164-2812, United States; U.S. Geological Survey, Menlo Park, CA 94025, United States 6 Hydrothermal alterations; Isotopic composition; Lacustrine sediments; Metamorphic core complex; Off-axis magmatism; Snake river plains; Standard mean ocean waters; Vertical component, Basalt; Faulting; Geochronology; Hafnium; Isotopes; Lead; Neodymium; Rivers; Strontium; Volcanoes; Watersheds; Zircon, Granite, basalt; basin evolution; caldera; detachment fault; faulting; geochronology; hafnium; hydrothermal alteration; igneous geochemistry; ignimbrite; isotopic composition; lacustrine deposit; lava flow; magmatism; Miocene; oxygen isotope; range expansion; rhyolite; uranium-lead dating; volcanic eruption; zircon, Idaho; Raft River; Snake River Plain; United States, Tetraonidae https://www.scopus.com/inward/record.uri?eid=2-s2.0-84889670967&doi=10.1130%2fGES00948.1&partnerID=40&md5=ebb1b1f756a6062f2d8b778b55fcf7c9 cited By 15 A. Konstantinou J. Valley A. Strickland E.L. Miller C. Fisher J. Vervoort J. Wooden article Snyder20131309 The Lake El'gygytgyn sediment record contains an abundant diatom flora through most intervals of the lake's history, providing a means to create and test hypotheses concerning the lake's response to changing climates. The 0-1.2 Ma core interval is characterized by shifts in the dominant planktonic genera and events of exceptional concentration and diversity. Warm interglacial intervals have enhanced concentration and diversity of the plankton. This response is most extreme during exceptional events corresponding to marine isotope stages (MIS) 11 and 31. Diatom concentration and diversity also increase during some cold intervals (e.g., MIS 2), suggesting conditions of lake circulation and nutrient cycling promoting diatom production during these events. Short intervals of low plankton concentration accompanied by shifts in the dominant genus of the lake suggest conditions during certain cold events generate a severe impact on plankton production. The absence of these events during extended intervals of low summer insolation variability suggests a muted cold-event response of the lake system linked to regional climate. © Author(s) 2013. 2013 English 18149324 10.5194/cp-9-1309-2013 Climate of the Past 9 1309-1319 Department of Geology, Bowling Green State University, Bowling Green, OH 43403, United States; Institute of Biology and Soil Science, FEB RAS, 159 Prospect 100-Letiya, 690022 Vladivostok, Russian Federation 3 climate variation; diatom; dominance; interglacial; nutrient cycling; paleoclimate; paleoenvironment; physiological response; primary production; regional climate; species diversity, Chukchi; Elgygytgyn Lake; Russian Federation https://www.scopus.com/inward/record.uri?eid=2-s2.0-84883636267&doi=10.5194%2fcp-9-1309-2013&partnerID=40&md5=1cac7ddab852f14a941844d114cc52d7 cited By 15 J.A. Snyder M.V. Cherepanova A. Bryan article article 2012 09 Climate of the Past Discussions 8 4333–4355 B. Wagner Alexander Francke R. Sulpizio Giovanni Zanchetta Katja Lindhorst Sebastian Krastel Hendrik Vogel Janet Rethemeyer Gerhard Daut Andon Grazhdani Bashkim Lushaj Sasho Trajanovski article Geissler201212 In 2004 and 2005 a passive seismic experiment was carried out in the northern and northeastern part of the Bohemian Massif (Sudetes) to study the lithospheric structure. We present results from Ps and Sp receiver function analyses. With one exception, Moho depth at stations in the northwestern part of the study area varies between 28 and 32km. Thicker crust up to 35km was mapped toward the south (Moldanubian unit) and toward the east (Moravo-Silesian and Brunovistulian units) confirming results from previous active seismic measurements. There exists a relatively sharp step in Moho depth between units of the central Sudetes (~30km) and the Moravo-Silesian unit (~35km). The v p/v s ratios inverted from primary and multiple Moho Ps conversions hint for different crustal compositions of the units. Toward the Carpathian thrust we have no clear indications for any crustal root or slab beneath the western Carpathians. However, our data suggests a deepening of the Moho or at least a complicated crust-mantle transition in this area. Additional Ps phases were observed between 6 and 10s delay time in the Sudetes. These phases cannot be explained by Moho reverberations, but are most probably caused by low velocity zones in the middle crust or lithospheric mantle as shown by modeling of theoretical receiver functions. The stations showing these abnormal phases are located in the area of Permo-Carboniferous basins on probably Teplá-Barrandian crust. Therefore we assume that the phases hint at a mid-crustal low velocity zone between 16 and 20km depth, which is interpreted as a felsic solidified magma reservoir of the Permo-Carboniferous volcanism beneath the Sudetic Basins. Sp receiver functions show phases with negative polarity at 9 to 12s lead time on average, which we interpret as lithosphere-asthenosphere boundary at about 80 to 110km depth. © 2012 Elsevier B.V. Review 2012 English 00401951 10.1016/j.tecto.2012.05.005 Tectonophysics 564-565 12 – 37 Bohemian Massif; Sudetes; Seismology; Central Europe; ratio; Lithosphere-asthenosphere boundary; Lithospheric structure; Moho discontinuity; Permo-Carboniferous volcanism; asthenosphere; Carboniferous; crust-mantle boundary; crustal structure; lithospheric structure; magma chamber; Moho; observational method; Permian; S-wave; seismic tomography; seismic velocity; velocity structure; volcanism; Structural geology https://www.scopus.com/inward/record.uri?eid=2-s2.0-84865163267&doi=10.1016%2fj.tecto.2012.05.005&partnerID=40&md5=fdf1dfe64b5aaaa898d13c96d2b55d67 Cited by: 23 Wolfram H. Geissler Horst Kämpf Zuzana Skácelová Jaroslava Plomerova Vladislav Babuška Rainer Kind article Lin2012665 Microearthquakes with magnitude down to 0.3 were detected by the Taiwan Chelungpu-fault Drilling Project Borehole Seismometers (TCDPBHS). Despite the large coseismic slip of 12m at the drill site during the 1999 Chi-Chi earthquake, our studies show very little seismicity near the TCDPBHS drill site 6 yr after the Chi-Chi main shock. The microearthquakes clustered at a depth of 9-12 km, where the Chelungpu thrust fault turns from a 30° dipping into the horizontal decollement of the Taiwan fold-and-thrust tectonic structure. Continuous GPS surveys did not observe post-slip deformation at the larger slip region and no seismicity was observed near the drill site. Therefore we suggest that the thrust belt above the decollement is locked during this interseismic period. We further investigated source parameters of 242 microearthquakes by fitting ω -2-shaped Brune source spectra to our observation data using a frequency-independent Q model. We find that the static stress drop increases significantly with increasing seismic moment. However, due to the intense debate on this topic of scaling-relations and the related self-similarity of earthquakes, we further improve the data analysis and correct for path and site effects using the Projected Landweber Deconvolution (PLD) method for events within some clusters. The PLD method analyses the source time functions of the larger and the smaller event by an iterative technique. As a result we received source dimensions and stress drops of larger events including path and site effect corrections. The results from the PLD method are less scattered and also show a positive relation between static stress drop and seismic moment. We find a similar positive trend for the apparent stress scaling with seismic moment. © 2012 The Authors Geophysical Journal International © 2012 RAS. 2012 English 0956540X 10.1111/j.1365-246X.2012.05513.x Geophysical Journal International 190 665-676 Department of Earth Sciences, Institute of Geophysics, National Central University, Jhongli, Taiwan; NORSAR, Kjeller, Norway 1 Apparent stress; ChiChi earthquake; Coseismic slips; Drill sites; Drilling projects; Earthquake source; GPS survey; Inter-seismic periods; Iterative technique; Main shock; Method analysis; Micro-earthquakes; Observation data; Seismic moment; Seismotectonics; Self-similarities; Site effects; Source dimensions; Source parameters; Source time functions; Static stress; Stress drop; Tectonic structure; Thrust belts; Thrust faults, Boring; Drills; Drops; Faulting; Seismographs, Earthquakes, Chi-Chi earthquake 1999; decollement; deformation; earthquake magnitude; fold and thrust belt; microearthquake; seismic moment; seismicity; seismograph; seismotectonics; source parameters; tectonic structure; thrust fault, Chelungpu Fault Zone; Taiwan https://www.scopus.com/inward/record.uri?eid=2-s2.0-84862209007&doi=10.1111%2fj.1365-246X.2012.05513.x&partnerID=40&md5=b052a2d4145ba327e71823f826f5ca29 cited By 13 Y.-Y. Lin K.-F. Ma V. Oye article Cvetkoska_Levkov_Reed_2012 2012 Dec. 10.59194/MJEE12141-207c Macedonian Journal of Ecology and Environment 14 7–18 1-2 https://www.mjee.org.mk/index.php/mjee/article/view/96 Aleksandra Cvetkoska Zlatko Levkov Jane Reed article melezhik2012reading 2012 Springer Science & Business Media Victor Melezhik Anthony R Prave Eero J Hanski Anthony E Fallick Aivo Lepland Lee R Kump Harald Strauss article melezhik2012reading 2012 Springer Science and Business Media Victor Melezhik Anthony R Prave Anthony E Fallick Lee R Kump Harald Strauss Aivo Lepland Eero J Hanski article Hoffmann201294 Lake Ohrid (between FYR of Macedonia and Albania), situated in an active tectonic region of the Balkanides, is characterized by N - S trending active faults. To reconstruct the Holocene shoreline evolution we investigated the coastline using sediment cores and geophysical methods to image sedimentary and tectonic structures. We revealed areas of differing sedimentation regimes. The plains north and south of the lake are dominated by clastic input related to climate variations and uplift/erosion, whereas the steep western and eastern margins are controlled by recent tectonics. Furthermore, no evidence for a much higher lake-level during the Holocene was found in the plains north and south of the lake, except rare temporary floodings. This is supported by mappings of the limestone cliffs around Lake Ohrid, which yielded no evidence for abrasional platforms or notches as indicators for past highstands. © 2012 Versita Warsaw and Springer-Verlag Wien. Article 2012 English 18961517 10.2478/s13533-011-0063-x Central European Journal of Geosciences 4 94 – 110 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84858738648&doi=10.2478%2fs13533-011-0063-x&partnerID=40&md5=d9f631492ee6e557f5a4232fe1f81d36 Cited by: 8; All Open Access, Hybrid Gold Open Access Nadine Hoffmann Klaus Reicherter Christoph Grützner Jochen Hürtgen Andreas Rudersdorf Finn A. Viehberg Martin Wessels book Goderis2012223 2012 10.1002/9781118447307.ch15 Impact Cratering: Processes and Products 223-239 Earth System Science, Vrije Universiteit Brussel, Pleinlaan 2, BE-1050 Brussels, Belgium; Department of Analytical Chemistry, Universiteit Gent, Krijgslaan 281 - S12, BE-9000 Ghent, Belgium; Department of Geology and Geophysics, University of Hawaii at Manoa, Honolulu, HI, United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-84883214338&doi=10.1002%2f9781118447307.ch15&partnerID=40&md5=16a29e5b97cf929ed5805213270b3fd6 cited By 37 S. Goderis F. Paquay P. Claeys article Wagner20122069 Lake Ohrid shared by the Republics of Albania and Macedonia is formed by a tectonically active graben within the south Balkans and suggested to be the oldest lake in Europe. Several studies have shown that the lake provides a valuable record of climatic and environmental changes and a distal tephrostratigraphic record of volcanic eruptions from Italy. Fault structures identified in seismic data demonstrate that sediments have also the potential to record tectonic activity in the region. Here, we provide an example of linking seismic and sedimentological information with tectonic activity and historical documents. Historical documents indicate that a major earthquake destroyed the city of Lychnidus (today: city of Ohrid) in the early 6th century AD. Multichannel seismic profiles, parametric sediment echosounder profiles, and a 10.08 m long sediment record from the western part of the lake indicate a 2 m thick mass wasting deposit, which is tentatively correlated with this earthquake. The mass wasting deposit is chronologically well constrained, as it directly overlays the AD 472/AD 512 tephra. Moreover, radiocarbon dates and cross correlation with other sediment sequences with similar geochemical characteristics of the Holocene indicate that the mass wasting event took place prior to the onset of the Medieval Warm Period, and is attributed it to one of the known earthquakes in the region in the early 6th century AD. © Author(s) 2012. Article 2012 English 18149332 10.5194/cp-8-2069-2012 Climate of the Past 8 2069 – 2078 6 Lake Ohrid; depositional environment; earthquake trigger; environmental change; geochemical method; Holocene; sedimentology; seismic data; tephrochronology; volcanic eruption https://www.scopus.com/inward/record.uri?eid=2-s2.0-84871809728&doi=10.5194%2fcp-8-2069-2012&partnerID=40&md5=43f5dfc8bc21882a2399a0a776ddf2ca Cited by: 28; All Open Access, Gold Open Access, Green Open Access B. Wagner A. Francke R. Sulpizio G. Zanchetta K. Lindhorst S. Krastel H. Vogel J. Rethemeyer G. Daut A. Grazhdani B. Lushaj S. Trajanovski article Park201263 Platinum group element (PGE) abundances in the upper continental crust (UCC) are poorly constrained with published values varying by up to an order of magnitude. We evaluated the validity of using loess to estimate PGE abundances in the UCC by measuring these elements in seven Chinese loess samples using a precise method that combines NiS fire assay with isotope dilution. Major and trace elements of the Chinese loess show a typical upper crustal composition and PGE abundances are consistent with literature data on Chinese loess, except for Ru, which is a factor of 10 lower than published values. We suggest that the high Ru data and RuN/IrN values of Chinese loess reported by Peucker-Ehrenbrink and Jahn (2001) (Geochem. Geophys. Geosys. 2, 2001GC000172) are an analytical artifact, rather than a true geochemical characteristic of loess because likely sources of loess are not significantly enriched in Ru and transport and deposition processes cannot preferentially enrich Ru in loess. The effect of eolian fractionation on PGE abundances in loess appears to be limited because Chinese loess from different locations shows similar PGE patterns and concentrations. This conclusion is supported by strong positive correlations between the PGE (except for Pt) and other compatible elements such as Fe2O3, Ni, Cr, Co. Using a compilation of PGE data for loess from China, Argentina and Europe, including our data but excluding one sample with an anomalously high Pt content, we propose average PGE abundances for global loess of Ir = 0.022 ppb (ng/g), Ru = 0.030 ppb, Rh = 0.018 ppb, Pt = 0.599 ppb, and Pd = 0.526 ppb, and suggest that these are the best current estimates for the PGE abundances of the UCC. © 2012 Elsevier Ltd. 2012 10.1016/j.gca.2012.06.026 Geochimica et Cosmochimica Acta 93 63-76 Research School of Earth Sciences, Australian National University, Canberra 0200, ACT, Australia; State Key Laboratory of Geological Processes and Mineral Resources, Faculty of Earth Sciences, China University of Geosciences, Wuhan 430074, China; State Key Laboratory of Continental Dynamics, Department of Geology, Northwest University, Xi'an 710069, China https://www.scopus.com/inward/record.uri?eid=2-s2.0-84864748372&doi=10.1016%2fj.gca.2012.06.026&partnerID=40&md5=4506b2b2e172f1b97e1d999d11ab9d81 cited By 56 J.-W. Park Z. Hu S. Gao I.H. Campbell H. Gong article Boulton2012 We present a unified analysis of physical properties of cataclastic fault rocks collected from surface exposures of the central Alpine Fault at Gaunt Creek and Waikukupa River, New Zealand. Friction experiments on fault gouge and intact samples of cataclasite were conducted at 30-33MPa effective normal stress (n) using a double-direct shear configuration and controlled pore fluid pressure in a true triaxial pressure vessel. Samples from a scarp outcrop on the southwest bank of Gaunt Creek display (1) an increase in fault normal permeability (k=7.45×10-20 m2 to k=1.15×10-16 m2), (2) a transition from frictionally weak (=0.44) fault gouge to frictionally strong (=0.50-0.55) cataclasite, (3) a change in friction rate dependence (a-b) from solely velocity strengthening, to velocity strengthening and weakening, and (4) an increase in the rate of frictional healing with increasing distance from the footwall fluvioglacial gravels contact. At Gaunt Creek, alteration of the primary clay minerals chlorite and illite/muscovite to smectite, kaolinite, and goethite accompanies an increase in friction coefficient (=0.31 to =0.44) and fault-perpendicular permeability (k=3.10×10-20 m2 to k=7.45×10-20 m2). Comminution of frictionally strong (=0.51-0.57) cataclasites forms weaker (=0.31-0.50) foliated cataclasites and fault gouges with behaviors associated with aseismic creep at low strain rates. Combined with published evidence of large magnitude (Mw∼8) surface ruptures on the Alpine Fault, petrological observations indicate that shear failure involved frictional sliding within previously formed, velocity-strengthening fault gouge. Copyright 2012 by the American Geophysical Union. 2012 English 15252027 10.1029/2011GC003872 Geochemistry, Geophysics, Geosystems 13 Blackwell Publishing Ltd Department of Geological Sciences, University of Canterbury, PB 4800, Christchurch 8042, New Zealand; Department of Geosciences, Pennsylvania State University, 522 Deike Building, University Park, PA 16802, United States; Department of Geology, University of Otago, P.O. Box56, Dunedin 9054, New Zealand 1 Clay alteration; Friction; Grinding (comminution); Kaolin; Kaolinite; Mechanical permeability; Physical properties; Shear flow; Strain rate; Strengthening (metal); Tribology, Alpine Faults; Cataclasite; Effective normal stress; Fault gouge; Fault rock; Friction coefficients; Frictional sliding; Low strain rates; New zealand; Pore fluid pressure; Rate dependence; Shear failure; Smectites; Surface exposure; surface rupture; Surface ruptures; True triaxial; Unified analysis, Surface properties, cataclasite; earthquake rupture; fault; fault gouge; fault zone; friction; outcrop; permeability; physical property; plate tectonics, Alpine Fault Zone; New Zealand; South Island https://www.scopus.com/inward/record.uri?eid=2-s2.0-84856533853&doi=10.1029%2f2011GC003872&partnerID=40&md5=f96ec4f4ed8a49057d0de938fc093b59 cited By 76 C. Boulton B.M. Carpenter V. Toy C. Marone article Gao2012669 The well SK-I in the Songliao Basin is the first scientific borehole targeting the continental Cretaceous strata in China. Oval concretions, thin laminae and beds of dolostone are found intercalated within mudstone and organic-rich black shale in the Nenjiang Formation of Campanian age. Low ordered ferruginous dolomite is composed of euhedral-subhedral rhombs with cloudy nucleus and light rims formed during the diagenesis, which are typical features of replacement. The heavy carbon isotopes (δ13CPDB - 1.16-16.0) are results of both the fermentation of organic matter by microbes and degassing of carbon dioxide during the period of diagenesis, and the presence of light oxygen isotopes (δ18OPDB - 18.53∼-5.1) is a characteristic feature of fresh water influence which means the carbonate may have been altered by ground water or rainwater in the late diagenesis. Marine water incursions into the normally lacustrine basin have been proved by both the salinity of Z value and the occurrence of foraminifera in the same strata where dolomite occurs. Pyrite framboids observed by SEM are usually enclosed in the dolomite crystals or in the mudstones, supporting the sulfate reducing bacteria (SRB). The formation of both dolomite and pyrite are associated with marine water incursions, which not only supply magnesium ion for dolomite, but also result in limited carbonate precipitation in the basin. The presence of pyrite framboids indicates the development of an anoxic environment associated with salinity stratification in the lake. The dolomite in the Nenjiang Formation is the results of marine water incursions, diagenetic replacement of calcareous carbonate and sulfate reducing bacteria (SRB). © 2012 Elsevier B.V. All rights reserved. 2012 English 16749871 10.1016/j.gsf.2011.12.014 Geoscience Frontiers 3 Elsevier B.V. 669-680 Science Research Institute, China University of Geosciences, Beijing 100083, China; National Laboratory of Mineral Materials, China University of Geosciences, Beijing 100083, China; Institute of Mineral Resources, Chinese Academy of Geological Sciences, Beijing 100037, China 5 bacterium; black shale; borehole; Campanian; carbon isotope; carbonate; diagenesis; dolostone; lithostratigraphy; mudstone; oxygen isotope; petrology; precipitation (chemistry); pyrite, China; Songliao Basin, Foraminifera https://www.scopus.com/inward/record.uri?eid=2-s2.0-84865346133&doi=10.1016%2fj.gsf.2011.12.014&partnerID=40&md5=1f303ef72fbb4872b5d7c2b0fd0637a0 cited By 8 X. Gao P. Wang D. Li Q. Peng C. Wang H. Ma article Nelson20121 The drill core from the International Continental Drill Program's Chicxulub Scientific Drilling Project Yaxcopoil-1 (Yax-1) borehole, in the annular trough of the Chicxulub crater, exhibits from 794 to 895. m a continuous sequence of impactites consisting of reworked fallout, fallout suevite, and brecciated impact melt rock. These impact breccias exhibit a complex history of deposition, fracturing, matrix emplacement and hydrothermal alteration. Detailed investigation of the mineralogy and chemistry of these breccias has led to a better understanding of the complex events involved in their formation. We find that the paragenesis of the brecciated impact melt rock (unit 5, 861-885. m) involved fracturing of melt rock and early K-metasomatism during a hydrothermal alteration episode as suggested by earlier work. However, the present work has identified the role of multiple episodes of precipitation of Mg-rich phyllosilicates and formation and dissolution of accessory minerals in a relatively high temperature (>300. °C) hydrothermal event. The earliest matrix formation event involved precipitation of Mg-rich phyllosilicate, accessory quartz, calcite, apatite, and andradite garnet from a hydrothermal fluid with a brine or seawater component. The fluid could have partly incorporated elements and shock-metamorphosed mineral phases derived from sedimentary lithologies, including calcite and dolomite that underwent complex phase transformations such as melting, decomposition and possible back-reactions. The discovery of andradite garnet in the matrix confirms the presence of an early high temperature hydrothermal event previously identified by mineralogical, stable isotope and fluid inclusion studies. The mineral assemblage, including Mg-rich saponite, suggests the involvement of seawater by comparison with similar alteration assemblages in hydrothermal systems involving seawater around the world. The presence of a later, low-temperature phase of the hydrothermal system, with different fluid chemistry is indicated by the partial dissolution of andradite garnet, and continued precipitation of matrix phyllosilicate minerals, but without the accessory quartz, abundant calcite or andradite, and without an accompanying K-metasomatism event. © 2012 Elsevier Ltd. 2012 10.1016/j.gca.2012.02.022 Geochimica et Cosmochimica Acta 86 1-20 Univ. of New Mexico MSC03 2050, Institute of Meteoritics, Dept. of Earth and Planetary Sciences, Albuquerque, NM 87131, United States; Bruker Nano GmbH, Schwarzschildstrasse 12, 12489 Berlin, Germany https://www.scopus.com/inward/record.uri?eid=2-s2.0-84860550760&doi=10.1016%2fj.gca.2012.02.022&partnerID=40&md5=b2706d92b2fafc1d0de4ed4115b05013 cited By 11 M.J. Nelson H.E. Newsom M.N. Spilde T. Salge article Poste2012340 Lake sediment cores have been used to reconstruct mercury deposition patterns in many parts of the world; however, no studies to date have used these methods in West Africa, nor are there any published measurements of mercury deposition to this region. We measured mercury in a 210Pb dated sediment core from a meromictic crater lake in West Africa (Lake Bosomtwe, Ghana). Lake Bosomtwe has a very small catchment area to lake area ratio (1.1) and the sediment mercury profile is expected to reflect past and present atmospheric mercury deposition to the lake. Mercury concentrations in sediments as well as mercury flux to the sediments increased from the mid-1800s to latter half of the 1900s, however there has been a sharp decline in mercury flux to Lake Bosomtwe in recent decades. The recent decline in mercury flux to Lake Bosomtwe's sediments does not appear to be consistent with trends in local, regional or global mercury emissions, and may instead reflect declining global atmospheric mercury concentrations or declining European emissions, highlighting the importance of long-range atmospheric transport of mercury. © 2012 Elsevier B.V. Article 2012 English 18791026 10.1016/j.scitotenv.2012.01.022 Science of the Total Environment 420 340 – 344 Air Movements; Air Pollution; Environmental Monitoring; Environmental Pollution; Geologic Sediments; Ghana; History, 19th Century; History, 20th Century; Lakes; Mercury; Ashanti; Ghana; Lake Bosumtwi; Anoxic sediments; Atmospheric chemistry; Atmospheric movements; Lakes; Lead; Mercury (metal); Sedimentology; cesium 137; lead 210; mercury; Africa; Atmospheric mercury; Atmospheric mercury deposition; Atmospheric transport; Crater lake; Global mercury emissions; Lake areas; Lake sediments; Long-range atmospheric transport; Mercury concentrations; Mercury depositions; Mercury fluxes; Past and present; Sediment core; Small catchment; West Africa; catchment; concentration (composition); crater lake; deposition; lacustrine deposit; mercury (element); meromictic lake; sediment core; article; catchment; chemical analysis; chemical composition; concentration (parameters); controlled study; geographic distribution; Ghana; isotope labeling; lake; lake sediment; pollution transport; priority journal; sedimentation rate; trend study; water pollution; Lake pollution https://www.scopus.com/inward/record.uri?eid=2-s2.0-84857644926&doi=10.1016%2fj.scitotenv.2012.01.022&partnerID=40&md5=523ac22cabe44b0f34a00d3378b763f7 Cited by: 4 Amanda E. Poste Derek C.G. Muir Megan K. Otu Roland I. Hall Robert E. Hecky article Dubreuil-Boisclair201220 For the past decades, gas hydrate reservoirs have beneficiated from an increasing attention in the academic and industrial worlds. As a result, there is a growing need to develop specific and comprehensive gas hydrate reservoir characterization methods. This study explores the use of a stochastic Bayesian algorithm to integrate well-logs and 3D acoustic impedance in order to estimate gas hydrate grades (product of saturation and total porosity) over a representative volume of the Mallik gas hydrate field, located in the Mackenzie Delta, Northwest Territories of Canada. First, collocated log data from boreholes Mallik 5L-38 and 2L-38 are used to estimate the statistical relationship between acoustic impedance and gas hydrate grades. Second, conventional stochastic Bayesian simulation is applied to generate multiple gas hydrate grade 3D fields integrating log data and lateral variability of 3D acoustic impedance. These equiprobable scenarios permit to quantify the uncertainty over the estimation, and identify zones where this uncertainty is greater. Contrary to conventional stochastic reservoir modeling workflows, the proposed method allows integrating non Gaussian and non linear distributions. This permits to handle bimodal distributions without using complex stochastic transforms. The results present gas hydrate grade values that are in accordance with well-log data. The relatively low standard deviation calculated at each pixel using all realizations suggests that gas hydrate grades is well explained by acoustic impedance and log data. © 2012 Elsevier Ltd. 2012 English 02648172 10.1016/j.marpetgeo.2012.02.020 Marine and Petroleum Geology 35 20-27 INRS-Centre Eau Terre Environnement, 490, rue de la Couronne, Québec, QC, G1K 9A9, Canada; Geological Survey of Canada, 615 Booth Street, Ottawa, ON, K1A 0E9, Canada; Dept. C.G.M. Ecole Polytechnique de Montréal, CP 6079 succ. centre-ville, Montréal, QC, H3C 3A7, Canada 1 Bayesian algorithms; Bayesian simulation; Bimodal distribution; Gas hydrate reservoir; Log data; Non-Gaussian; Non-linear distribution; Reservoir modeling; Standard deviation; Statistical relationship; Stochastic simulations; Total porosity; Well log data; Work-flows, Acoustic impedance; Estimation; Gases; Hydration; Stochastic models; Stochastic systems; Three dimensional; Three dimensional computer graphics; Well logging, Gas hydrates, acoustics; Bayesian analysis; borehole; gas field; gas hydrate; pixel; stochasticity; well logging, Canada; Mackenzie Delta; Northwest Territories https://www.scopus.com/inward/record.uri?eid=2-s2.0-84861706132&doi=10.1016%2fj.marpetgeo.2012.02.020&partnerID=40&md5=30e25bab92771cdb07c078ff68eaa438 cited By 34 C. Dubreuil-Boisclair E. Gloaguen G. Bellefleur D. Marcotte article Wenk2012123 A sample of biotite gneiss from the Outokumpu deep drilling project in Finland was investigated by Kern et al. (2008) for crystal preferred orientation and elastic anisotropy. Considerable differences between measured acoustic velocities and velocities calculated on the basis of texture patterns were observed. Measured P-wave anisotropy was 15.1% versus a Voigt average yielding 7.9%. Here we investigate the same sample with different methods and using different averaging techniques. Analyzing time-of-flight neutron diffraction data from Dubna-SKAT and LANSCE-HIPPO diffractometers with the Rietveld technique, much stronger preferred orientation for biotite is determined, compared to conventional pole-figure analysis reported previously. The comparison reveals important differences: HIPPO has much better counting statistics but pole figure coverage is poor. SKAT has better angular resolution. Using the new preferred orientation data and applying a self-consistent averaging method that takes grain shapes into account, close agreement of calculated and measured P-wave velocities is observed (12.6%). This is further improved by adding 0.1. vol.% flat micropores parallel to the biotite platelets in the simulation (14.9%). © 2012. Article 2012 English 00401951 10.1016/j.tecto.2012.06.023 Tectonophysics 570-571 123 – 134 Finland; Outokumpu; Pohjois-Karjala; Acoustic wave velocity measurement; Anisotropy; Neutron diffraction; Poles; Seismic waves; Textures; Angular resolution; Averaging method; Averaging technique; Biotite gneiss; Counting statistics; Crystal preferred orientations; Deep drilling; Drill hole; Elastic anisotropy; Finland; Gneiss; Grain shapes; Micropores; Neutron diffraction data; P-wave velocity; Pole figure; Pole figure analysis; Preferred orientations; Rietveld technique; Self-consistent averaging; Texture measurement; Texture patterns; Time of flight; Velocity calculations; biotite; crystal property; elastic property; gneiss; measurement method; neutron diffraction; P-wave; preferred orientation; seismic anisotropy; seismic velocity; texture; Mica https://www.scopus.com/inward/record.uri?eid=2-s2.0-84866516721&doi=10.1016%2fj.tecto.2012.06.023&partnerID=40&md5=1932f53c9a1dac9a24d480fa513391f4 Cited by: 46 H.-R. Wenk R.N. Vasin H. Kern S. Matthies S.C. Vogel T.I. Ivankina article sd-13-65-2012 2012 10.5194/sd-13-65-2012 13 65-71 https://sd.copernicus.org/articles/13/65/2012/ article Recasens20121323 A series of long sediment cores was retrieved from Laguna Potrok Aike, Southern Patagonia, within the framework of PASADO (Potrok Aike Maar Lake Sediment Archive Drilling Project), an ICDP (International Continental Scientific Drilling Program) lake drilling project. This maar lake, located at 52°S, 70°W in the Province of Santa Cruz (Argentina), in the southernmost continental area of the world, is one of the few permanent lakes in the region, providing a unique continuous paleoclimatic and paleoecological lacustrine record for the last glacial cycle. Previous multiproxy studies of this site have characterized the environmental history of these dry lands in the Patagonian Steppe for the last 16 cal. ka BP. This new series of sediment cores provides a much longer record of climate variability in Southern Patagonia since 51.3 cal. ka BP. Using a multiproxy strategy, a set of samples (mostly from core catcher material) was analyzed for physical properties, rock magnetism, geochemistry, CNS elemental analysis, stable isotopes, pollen and diatoms. This preliminary multiproxy limnogeological interpretation sheds new light on the regional Pleistocene and Holocene environmental history, revealing lake-level variations through time and identifying time windows of interest where higher resolution analyses will be carried out. © The Author(s) 2011. Article 2012 10.1177/0959683611429833 Holocene 22 1323 – 1335 11 Argentina; Laguna Potrok Aike; Patagonia; Santa Cruz [Argentina]; diatom; lacustrine deposit; paleoclimate; paleoecology; paleoenvironment; palynology; Pleistocene; proxy climate record; sediment core; stable isotope https://www.scopus.com/inward/record.uri?eid=2-s2.0-84867669582&doi=10.1177%2f0959683611429833&partnerID=40&md5=65e04f1777f20a54e5cc8523a8bb6b99 Cited by: 40; All Open Access, Green Open Access Cristina Recasens Daniel Ariztegui Catalina Gebhardt Claudia Gogorza Torsten Haberzettl Annette Hahn Pierre Kliem Agathe Lisé-Pronovost Andreas Lücke Nora Maidana Christoph Mayr Christian Ohlendorf Frank Schäbitz Guillaume St-Onge Michael Wille Bernd Zolitschka article Hiemer2012169 The most recent intense earthquake swarm in West Bohemia lasted from 6 October 2008 to January 2009. Starting 12 days after the onset, the University of Potsdam monitored the swarm by a temporary small-aperture seismic array at 10 km epicentral distance. The purpose of the installation was a complete monitoring of the swarm including micro-earthquakes (M L < 0). We identify earthquakes using a conventional short-term average/long-term average trigger combined with sliding-window frequency-wavenumber and polarisation analyses. The resulting earthquake catalogue consists of 14,530 earthquakes between 19 October 2008 and 18 March 2009 with magnitudes in the range of - 1.2 ≤ M L ≤ 2. 7. The small-aperture seismic array substantially lowers the detection threshold to about M c = - 0.4, when compared to the regional networks operating in West Bohemia (M c > 0.0). In the course of this work, the main temporal features (frequency-magnitude distribution, propagation of back azimuth and horizontal slowness, occurrence rate of aftershock sequences and interevent-time distribution) of the recent 2008/2009 earthquake swarm are presented and discussed. Temporal changes of the coefficient of variation (based on interevent times) suggest that the swarm earthquake activity of the 2008/2009 swarm terminates by 12 January 2009. During the main phase in our studied swarm period after 19 October, the b value of the Gutenberg-Richter relation decreases from 1.2 to 0.8. This trend is also reflected in the power-law behavior of the seismic moment release. The corresponding total seismic moment release of 1.02×10 17 Nm is equivalent to M L,max = 5. 4. © 2011 Springer Science+Business Media B.V. Article 2012 English 13834649 10.1007/s10950-011-9256-5 Journal of Seismology 16 169 – 182 2 Bohemia; Czech Republic; aftershock; earthquake catalogue; earthquake magnitude; earthquake swarm; frequency analysis; microearthquake; monitoring; polarization; seismic moment; temporal variation https://www.scopus.com/inward/record.uri?eid=2-s2.0-84858156392&doi=10.1007%2fs10950-011-9256-5&partnerID=40&md5=eb1a23b70e199da3a3ad271441ebd5ba Cited by: 15 Stefan Hiemer Dirk Roessler Frank Scherbaum article Albrecht201247 The spatial distribution of (endemic) biodiversity in ancient and potentially ancient lakes in Europe is poorly understood. Examples include Lakes Prespa and Mikri Prespa in the Central Balkans. Utilizing information of the most species-rich taxon in these lakes, the Mollusca, we therefore attempt to statistically assess and visualize the spatial distribution of biodiversity, to analyse biogeographical patterns, and to carry out a conservation assessment. We estimate that at least 40 (sub)species (29 gastropod and 11 bivalve taxa) occur in the lakes. For both lakes combined, 37. 5% of the mollusc taxa are endemic. In general, the mollusc richness in Lake Mikri Prespa is lower than in Lake Prespa and less heterogeneously distributed. The highest species richness can be seen on the western and south eastern shores of Lake Prespa. Based on the presence/absence of genera, a minimum spanning tree analysis supports the sister lake relationship of both lakes, which, in turn, are most closely related to lakes in the western Balkans and not to nearby Lake Ohrid. The IUCN red list assessment revealed (A) a tendency towards mollusc faunal change, (B) a contemporary decline and potential loss of mollusc diversity, and (C) that all endemic species are of conservation concern. © 2011 Springer Science+Business Media B.V. Article 2012 English 15735117 10.1007/s10750-011-0830-1 Hydrobiologia 682 47 – 59 1 Lake Mikri Prespa; Bivalvia; Gastropoda; Mollusca; assessment method; biodiversity; biogeography; conservation management; endemic species; extinction; habitat conservation; heterogeneity; mollusc; population decline; Red List; spatial distribution; species conservation; species richness; taxonomy; visualization https://www.scopus.com/inward/record.uri?eid=2-s2.0-84856225957&doi=10.1007%2fs10750-011-0830-1&partnerID=40&md5=ed1342a09ce5a38bcc5ab444f3d8f080 Cited by: 18 Christian Albrecht Torsten Hauffe Kirstin Schreiber Thomas Wilke article Popov2012 We present a three-dimensional finite element thermomechanical model idealizing the complex deformation processes associated with evolution of the San Andreas Fault system (SAFS) in northern and central California over the past 20 Myr. More specifically, we investigate the mechanisms responsible for the eastward (landward) migration of the San Andreas plate boundary over time, a process that has largely determined the evolution and present structure of SAFS. Two possible mechanisms had been previously suggested. One mechanism suggests that the Pacific plate first cools and captures uprising mantle in the slab window, subsequently causing accretion of the continental crustal blocks. An alternative scenario attributes accretion to the capture of plate fragments (microplates) stalled in the ceased Farallon-North America subduction zone. Here we test both these scenarios numerically using a recently developed lithospheric-scale code, SLIM3D, that employs free surface, nonlinear temperature- and stress-dependent elastoviscoplastic rheology and allows for self-generation of faults. Modeling suggests that microplate capture is the primary driving mechanism for the eastward migration of the plate boundary, while the slab window cooling mechanism alone is incapable of explaining this phenomenon. We also show that the system evolves to the present day structure of SAFS only if the coefficient of friction at mature faults is low (0.08 for the best fit model). Thus, our model provides an independent constraint supporting the "weak fault in a strong crust" hypothesis for SAFS. © 2012. American Geophysical Union. All Rights Reserved. 2012 English 15252027 10.1029/2012GC004086 Geochemistry, Geophysics, Geosystems 13 Blackwell Publishing Ltd Section of Geodynamic Modeling, GeoForschungsZentrum, DE-14473 Potsdam, Germany; Now at Institute for Geosciences, Johannes Gutenberg University, DE-55099 Mainz, Germany; Schmidt Institute of Physics of the Earth, 123995 Moscow, Russian Federation; Department of Geophysics, Stanford University, Stanford, CA 94305-2215, United States 8 Friction; Geodynamics; Plates (structural components); Strike-slip faults; Tectonics, Best-fit models; California; Coefficient of frictions; Complex deformation; Cooling mechanism; Crustal block; Driving mechanism; Elasto-viscoplastic; Free surfaces; Microplates; Nonlinear temperature; Numeric models; Pacific plates; Plate boundaries; San Andreas fault; Self-generation; Slab windows; Stress-dependent; Subduction zones; Thermomechanical model; Three dimensional finite elements; weak fault in strong crust, Three dimensional, deformation; finite element method; friction; geodynamics; numerical model; Pacific plate; plate boundary; San Andreas Fault; subduction zone; tectonic evolution, California; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-84865788317&doi=10.1029%2f2012GC004086&partnerID=40&md5=ec0ef4838e29cfda147ea7d37e538d59 cited By 23 A.A. Popov S.V. Sobolev M.D. Zoback article Zhou2012983 Otoliths are biogenic carbonate minerals whose microstructure and microchemistry have been used for age determination, stock identification, life history and environmental tracing. Using X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy, we have determined the mineral types and crystalline characteristics of three pairs of otoliths from naked carp Gymnocypris przewalskii, the predominant fish in Lake Qinghai. The results indicate that the mineral of both lapillus and sagitta of the naked carp is aragonite, and that of asteriscus is vaterite. The aragonite of lapillus has prefect crystallization. Given the shape of lapillus and the sensitivity of its aragonite to water chemistry, lapillus was used to analyze temporal Sr/Ca ratios along the maximal growth axis by an electron probe microanalyzer (EPMA). Consistent variations of Sr/Ca ratios with a range of 1. 0×10-3-5. 0×10{combining triple dot above} on the long and short radii indicate that Sr/Ca ratios of lapillus potentially respond to the chemical compositions of the host waters during the period of the naked carp's growth and migration. Discontinuous (dark) zones of lapillus were formed during fall and winter when the naked carp grows slowly in Lake Qinghai, resulting in similar low Sr/Ca ratios to lake water, whereas incremental zones with higher Sr/Ca ratios respond to its migratory river waters during spring and summer. Various Sr/Ca ratios of incremental zones suggest that the migratory pattern of the naked carp may be much more flexible, rather than in a single river. Therefore, high-resolution otolith microchemistry of the naked carp can be used to trace its migratory behavior, which is of significance for determining its migratory pattern and life history of this precious species inhabiting the Tibetan Plateau. © 2012 Science China Press and Springer-Verlag Berlin Heidelberg. Article 2012 English 16747313 10.1007/s11430-012-4403-6 Science China Earth Sciences 55 Science in China Press 983 – 990 6 China; Qinghai; Qinghai Lake; Qinghai-Xizang Plateau; Asteriscus; Cyprinidae; Gymnocypris przewalskii; Sagitta; Carbonate minerals; Chemical analysis; Fourier transform infrared spectroscopy; Minerals; X ray diffraction; aragonite; Environmental tracers; Lake Qinghai naked carps; migration; otolith; Sr/ca ratios; aragonite; biogenic mineral; calcium; chemical composition; crystallization; cyprinid; mineralogy; otolith; strontium; tracer; Lakes https://www.scopus.com/inward/record.uri?eid=2-s2.0-84861666591&doi=10.1007%2fs11430-012-4403-6&partnerID=40&md5=00b3c2c0aeab241ef79bcd697cc5c87d Cited by: 7 Ling Zhou Zhangdong Jin Fuchun Li You Chen-Feng Wang Chia-Hui Miss Chen Huilun Xu Zhijie Iizuka Yoshiyuki Zhang Fei Jin Yu-an He Maoyong Shi Yuewei Qiu Xinning article van2012mineral 2012 Geochimica et Cosmochimica Acta 83 Elsevier 252--262 Mark A Zuilen Daniel Fliegel Aivo Lepland Yuangao Qu Anja Schreiber Alexander E Romashkin Pascal Philippot article qu2012methanotrophy 2012 Geobiology 10 Wiley Online Library 467--478 6 Yu Qu AE {\v{C}}rne A Lepland MA Van Zuilen article Shanahan201249 The Lake Bosumtwi sediment record represents one of the longest and highest-resolution terrestrial records of paleoclimate change available from sub-Saharan Africa. Here we report a new sediment age model framework for the last ~. 45. cal kyr of sedimentation using a combination of high-resolution radiocarbon dating, Bayesian age-depth modeling and lamination counting. Our results highlight the practical limits of these methods for reducing age model uncertainties and suggest that even with very high sampling densities, radiocarbon uncertainties of at least a few hundred years are unavoidable. Age model uncertainties are smallest during the Holocene (205. yr) and the glacial (360. yr) but are large at the base of the record (1660. yr), due to a combination of decreasing sample density, larger calibration uncertainties and increases in radiocarbon age scatter. For portions of the chronology older than ~. 35. cal kyr, additional considerations, such as the use of a low-blank graphitization system and more rigorous sample pretreatment were necessary to generate a reliable age depth model because of the incorporation of small amounts of younger carbon. A comparison of radiocarbon age model results and lamination counts over the time interval ~. 15-30. cal kyr agree with an overall discrepancy of ~. 10% and display similar changes in sedimentation rate, supporting the annual nature of sediment laminations in the early part of the record. Changes in sedimentation rates reconstructed from the age-depth model indicate that intervals of enhanced sediment delivery occurred at 16-19, 24 and 29-31. cal kyr, broadly synchronous with reconstructed drought episodes elsewhere in northern West Africa and potentially, with changes in Atlantic meridional heat transport during North Atlantic Heinrich events. These data suggest that millennial-scale drought events in the West African monsoon region were latitudinally extensive, reaching within several hundred kilometers of the Guinea coast. This is inconsistent with a simple southward shift in the mean position of the monsoon rainbelt, and requires changes in moisture convergence as a result of either a reduction in the moisture content of the tropical rainbelt, decreased convection, or both. © 2012 Elsevier B.V. Article 2012 English 00310182 10.1016/j.palaeo.2012.08.001 Palaeogeography, Palaeoclimatology, Palaeoecology 361-362 49 – 60 Ashanti; Ghana; Lake Bosumtwi; Sub-Saharan Africa; calibration; climate change; core analysis; drought; glacial-interglacial cycle; graphitization; heat transfer; Heinrich event; Holocene; laminar flow; moisture content; paleoclimate; radiocarbon dating; sedimentation rate; uncertainty analysis https://www.scopus.com/inward/record.uri?eid=2-s2.0-84866880919&doi=10.1016%2fj.palaeo.2012.08.001&partnerID=40&md5=bc3133df6b258859a109ff49092950ea Cited by: 30 Timothy M. Shanahan J. Warren Beck Jonathan T. Overpeck Nicholas P. McKay Jeffrey S. Pigati John A. Peck Christopher A. Scholz Clifford W. Heil John King article Xiao20121331 Conventional hydrochemical techniques and statistical analyses were applied to better understand the solute geochemistry and the hydrochemical process of shallow groundwater in the Qinghai Lake catchment. Shallow groundwater in the Qinghai Lake catchment is slightly alkaline, and is characterized by a high ion concentrations and low water temperature. The total dissolved solids (TDS) in most of the samples are <1,000 mg/L, i. e. fresh water and depend mainly on the concentration of SO 4 2-, Cl - and Na +. Groundwater table is influenced directly by the residents' groundwater consumption. Most of the groundwaters in the Qinghai Lake catchment belong to the Ca 2+(Na +) -HCO 3 - type, while the Qinghai Lake, part of the Buha (BHR) and the Lake Side (LS) samples belong to the Na +-Cl - type. The groundwater is oversaturated with respect to aragonite, calcite and dolomite, but not to magnesite and gypsum. Solutes are mainly derived from strong evaporite dissolution in Daotang, BHR and LS samples and from strong carbonate weathering in Hargai and Shaliu samples. Carbonate weathering is stronger than evaporite dissolution with weak silicate weathering in the Qinghai Lake catchment. Carbonate weathering, ion exchange reaction and precipitation are the major hydrogeochemical processes responsible for the solutes in the groundwater in the Qinghai Lake catchment. Most of the shallow groundwaters are suitable for drinking. More attention should be paid to the potential pollution of nitrate, chloride and sulfide in shallow groundwater in the future. © 2012 Springer-Verlag. Article 2012 English 18666299 10.1007/s12665-012-1576-4 Environmental Earth Sciences 67 1331 – 1344 5 China; Qinghai; Qinghai Lake; Carbonate minerals; Carbonation; Catchments; Chlorine compounds; Dissolution; Groundwater; Groundwater pollution; Gypsum; Hydrochemistry; Lakes; Runoff; Weathering; Carbonate weathering; Evaporite dissolution; Fresh Water; Ground water table; Groundwater consumption; Hydrochemical process; Hydrochemicals; Hydrogeochemical process; Ion concentrations; Ion exchange reactions; Low water; Qinghai Lake; Qinghai Tibet plateau; Shallow groundwater; Silicate weathering; Total dissolved solids; hydrogeochemistry; ion exchange; sampling; shallow water; solute; water table; water temperature; Groundwater geochemistry https://www.scopus.com/inward/record.uri?eid=2-s2.0-84867741285&doi=10.1007%2fs12665-012-1576-4&partnerID=40&md5=77b48ca485ebb07fc69a4286c7d9188f Cited by: 36 Jun Xiao Zhangdong Jin Fei Zhang Jin Wang article Suan2012191 We present new geochemical and sedimentological data from marginal marine strata of Penarth Bay, south Wales (UK) to elucidate the origin of widespread but enigmatic concentrations of vertebrate hard parts (bonebeds) in marine successions of Rhaetian age (late Triassic). Sedimentological evidence shows that the phosphatic constituents of the bonebeds were subjected to intense phosphatization in shallow current dominated settings and subsequently reworked and transported basinward by storms. Inter bedded organic-rich strata deposited under quiescent and poorly oxygenated conditions record enhanced phosphorus regeneration from sedimentary organic matter into the water column and probably provided the main source of phosphate required for heavy bonebed clast phosphatization. The stratigraphically limited interval showing evidence for oxygen depletion and accelerated P-cycling coincides with a negative 4‰ organic carbon isotope excursion, which possibly reflects supra-regional changes in carbon cycling and clearly predates the 'initial isotope excursion' characterizing many Triassic-Jurassic boundary strata. our data indicate that Rhaetian bonebeds are the lithological signature of profound, climatically driven changes in carbon cycling and redox conditions and support the idea of a multi-pulsed environmental crisis at the end of the Triassic, possibly linked to successive episodes of igneous activity in the central Atlantic Magmatic Province. Article 2012 English 00167649 10.1144/0016-76492011-045 Journal of the Geological Society 169 Geological Society of London 191 – 200 2 South Wales; United Kingdom; Wales; Vertebrata; Barium alloys; Isotopes; Lithology; Carbon isotope excursions; Central atlantic magmatic provinces; Environmental change; Environmental crisis; Sedimentary organic matter; Sedimentological data; Sedimentological evidence; Triassic-Jurassic boundary; carbon cycle; environmental change; geochemistry; Jurassic; mass extinction; organic matter; paleoenvironment; petrogenesis; phosphate; phosphatization; redox conditions; Rhaetian; sedimentology; stratigraphic boundary; stratigraphy; vertebrate; water column; Organic carbon https://www.scopus.com/inward/record.uri?eid=2-s2.0-84857820298&doi=10.1144%2f0016-76492011-045&partnerID=40&md5=c7beee9316f512bf3da9024b23a9d7a5 Cited by: 24; All Open Access, Green Open Access Guillaume Suan Karl B. Föllmi Thierry Adatte Brahimsamba Bomou Jorge E. Spangenberg Bas Schootbrugge article Becken201265 Fluids residing in interconnected porosity networks have a significant weakening effect on the rheology of rocks and can strongly influence deformation along fault zones. The magnetotelluric (MT) technique is sensitive to interconnected fluid networks and can image these zones on crustal and upper mantle scales. MT images have revealed several prominent electrical conductivity anomalies at the San Andreas Fault which have been attributed to the presence of saline fluids within such networks and which have been associated with tectonic processes. These models suggest that ongoing fluid release in the upper mantle and lower crust is closely related to the mechanical state of the crust. Where fluids are drained into the brittle crust, and where these fluids are kept at high pressures, fault creep is supported. Fluid fluxes from deeper levels, in combination with meteoric and crustal metamorphic fluid inflow, and in response to fault creep, leads to high-conductivity zones developing as fault zone conductors in the brittle portion of crust. In turn, the absence of crustal fluid pathways may be characteristic for mechanically locked segments of the fault. Here, MT models suggest that fluids are trapped at depth and kept at high pressures. We speculate that fluids may infiltrate neighboring rocks and in their wake induce non-volcanic tremor. © 2011 Springer Science+Business Media B.V. 2012 English 01693298 10.1007/s10712-011-9144-0 Surveys in Geophysics 33 Kluwer Academic Publishers 65-105 GFZ German Research Centre for Geosciences, Telegrafenberg, 14473 Potsdam, Germany; Institute of Geophysics, WWU, Corrensstr. 24, 48149 Münster, Germany 1 Creep; Fluids; Magnetotellurics; Strike-slip faults; Volcanic rocks, Electrical conductivity; High-conductivity zones; Interconnected porosity; Magnetotelluric studies; Metamorphic fluids; Non-volcanic tremors; San Andreas fault; Weakening effect, Structural geology, deformation mechanism; electrical conductivity; fault zone; high pressure; magnetotelluric method; porosity; rheology; San Andreas Fault, California; San Andreas; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-82955212963&doi=10.1007%2fs10712-011-9144-0&partnerID=40&md5=298ad4b0fd95956e5af0fad201454c77 cited By 67 M. Becken O. Ritter article Schulte2012737 The La Popa Basin in north-eastern Mexico features outstanding, continuous three-dimensional exposures of the Cretaceous-Palaeogene boundary event deposit in shallow shelf environments pierced by salt stocks. In the area to the south-east of the El Papalote diapir, the Cretaceous-Palaeogene deposit consists of two superimposed sedimentary units and erosively overlies upper Maastrichtian sand-siltstones with soft-sediment deformation and liquefaction structures. The basal unit 1 is an up to 8m thick chaotic, carbonate-rich bed that discontinuously fills incised gutters and channels. Besides abundant silicic and carbonate ejecta spherules from the Chicxulub impact, unit 1 includes large sandstone boulders and abundant shallow-water debris (for example, mud clasts, algae, bivalve shells, gastropod shells and vertebrate remains). Unit 1 is conformably overlain by unit 2. Distal to the diapir, unit 2 consists of a centimetre to decimetre-thick conglomeratic, coarse bioclast and spherule-bearing sandstone bed. Closer to the diapir, unit 2 becomes a metre-thick series of four to eight conglomeratic to fine-grained graded sandstone beds rich in shell debris and ejecta spherules. Unit 2 is conformably overlain by structureless to parallel laminated sandstone beds that may mark the return to the pre-event depositional regime. The sedimentary characteristics of the Cretaceous-Palaeogene deposit, including its erosive base, its sheet-like geometry, the presence of multiple, graded beds, evidence for upper flow regime conditions and the absence of bioturbation, support an origin by a short-term multiphase depositional event. The occurrence of soft-sediment deformation structures (for example, liquefaction) below the Cretaceous-Palaeogene deposit suggests that earthquakes were the first to occur at La Popa. Then, shelf collapse and strong backflow from the first tsunami waves may have triggered erosion and deposition by violent ejecta-rich hyperconcentrated density flows (unit 1). Subsequently, a series of concentrated density flows resulting from tsunami backwash surges may have deposited the multiple-graded bedding structures of unit 2. The specific depositional sequence and the Fe-Mg-rich as well as Si-K-rich composition of the ejecta spherules both provide a critical link to the well-known deep marine Cretaceous-Palaeogene boundary sites in the adjacent Burgos basin in north-eastern Mexico. Moreover, the pulse-like input of Chicxulub ejecta material at the base of the event deposit allows for correlation with other Cretaceous-Palaeogene boundary sites in the Gulf of Mexico and the Atlantic, as well as in Central and Northern America. The presence of diverse dinosaur and mosasur bones and teeth in the event deposit is the first observation of such remains together with Chicxulub ejecta material. These findings indicate that dinosaurs lived in the area during the latest Maastrichtian and suggest that the tsunami waves not only eroded deltas and estuaries but the coastal plain as well. © 2011 The Authors. Journal compilation © 2011 International Association of Sedimentologists. 2012 10.1111/j.1365-3091.2011.01274.x Sedimentology 59 737-765 GeoZentrum Nordbayern, Universität Erlangen, D-91054 Erlangen, Germany; Department of Sedimentary Geology, VU University of Amsterdam, Po Box 7161, 1007 MC Amsterdam, Netherlands; Institut für Planetologie, Universität Münster, D-48149 Münster, Germany; Bruker Nano GmbH, Schwarzschildstrasse 12, D-12489 Berlin, Germany 3 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84858701883&doi=10.1111%2fj.1365-3091.2011.01274.x&partnerID=40&md5=0a4a69929dc4c04dee30814691fe717e cited By 29 P. Schulte J. Smit A. Deutsch T. Salge A. Friese K. Beichel article Cohen20123 Scientific drilling to recover sediment core and fossil samples is a promising approach to increasing our understanding of species evolution in ancient lakes. Most lake drilling efforts to date have focused on paleoclimate reconstruction. However, it is clear from the excellent fossil preservation and high temporal resolution typical of lake beds that significant advances in evolutionary biology can be made through drill core studies coordinated with phylogenetic work on appropriate taxa. Geological records can be used to constrain the age of specific lakes and the timing of evolutionarily significant events (such as lake level fluctuations and salinity crises). Fossil data can be used to test speciation and biogeographic hypotheses and flesh out phylogenetic trees, using a better-resolved fossil record to estimate timing of phylogenetic divergences. The extraordinary preservation of many fossils in anoxic lake beds holds the hope of collecting fossil DNA from the same body fossils that improve our understanding of morphological character evolution and adaptation. Moreover, fossils allow calibration of molecular clocks, which are currently largely inferential. Lake Malawi Drilling Project results provide some guideposts on what might be expected in a drilling project for studies of evolution. The extreme variability in lake level and environmental history that most ancient lakes experience (exemplified by the Lake Malawi record) demonstrates that no one drilling locality is likely to provide a complete record of phylogenetic history for a radiating lineage. Evolutionary biologists should take an active role in the design of drilling projects, which typically have interdisciplinary objectives, to ensure their sampling needs will be met by whatever sites in a lake are ultimately drilled. © 2011 Springer Science+Business Media B.V. 2012 English 00188158 10.1007/s10750-010-0546-7 Hydrobiologia 682 3-25 Department of Geosciences, University of Arizona, Tucson, AZ 85721, United States 1 adaptation; biogeography; divergence; drilling; fossil record; interdisciplinary approach; lake; paleoclimate; paleoenvironment; paleolimnology; phylogenetics; reconstruction; resolution; salinity; sediment core; speciation (biology) https://www.scopus.com/inward/record.uri?eid=2-s2.0-84856228169&doi=10.1007%2fs10750-010-0546-7&partnerID=40&md5=b8c44e8f257de637e6500e71f0bc31dc cited By 25 A.S. Cohen article 2012 Quaternary Sciences 32 635-640 4 H. Li S. Zhang K. Zhao H. Wu T. Yang article Scott2012357 Non-marine ostracodes, charophytes and palynomorphs are abundant in most Cretaceous lacustrine basins of East Asia. However, their ranges are not directly integrated with marine biota that defines the Cretaceous stages. Non-biotic events such as magnetochrons and radiometric ages in these terrestrial deposits enable their correlation with marine strata. The SK1 north and south composited cores in the Songliao Basin present a continuous section of Upper Cretaceous non-marine fossil and magnetochron successions in superposed order. These chronostratigraphic events are integrated with marine events by an X/Y graphic plot between the core data and a global database of Global Section and Stratotype Points (GSSP) and key reference sections. This plot projects stage boundaries in marine sections into the SK1 section and interpolates numerical ages to the first and last occurrences of biota and to lithostratigraphic boundaries. This stratigraphic experiment tests and refines age calibrations based on both manual interpolation of depths to numerical ages and cyclostratigraphy. Ages derived by interpolation are similar and ages by cyclostratigraphy are older because stage boundaries are calibrated to a different age scale. © 2011, China University of Geosciences (Beijing) and Peking University. Production and hosting by Elsevier B.V. All rights reserved. 2012 English 16749871 10.1016/j.gsf.2012.02.004 Geoscience Frontiers 3 Elsevier B.V. 357-367 Department of Geosciences, University of Tulsa, Precision Stratigraphy Associates, Tulsa, OK 74104, United States; State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing 100083, China; Exploration and Development Research Institute, Daqing Oilfield Company Ltd., Daqing 163712, China 4 age determination; charophyte; chronostratigraphy; cyclostratigraphy; lithostratigraphy; Maastrichtian; ostracod; palynomorph; Turonian, China; Songliao Basin, Characeae; Ostracoda https://www.scopus.com/inward/record.uri?eid=2-s2.0-84862802789&doi=10.1016%2fj.gsf.2012.02.004&partnerID=40&md5=38ea058b62ddfc4b4a04cce490a5c7b7 cited By 42 R.W. Scott X. Wan C. Wang Q. Huang article Rodbell201258 2012 English 18168957 10.2204/iodp.sd.13.10.2011 Scientific Drilling 58-60 Union College, Schenectady, NY 12308, United States; Department of Geology and Planetary Science, University of Pittsburgh, 4107 O'Hara Street, SRCC Building, Pittsburgh, PA 15260-3332, United States 13 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84865356790&doi=10.2204%2fiodp.sd.13.10.2011&partnerID=40&md5=c1119654b49b1a30209d15a306ba2a18 cited By 4 D.T. Rodbell M.B. Abbott conference Sun20121839 Permeability is a key parameter in hydrocarbon exploration and reservoir analysis. Studies indicate that a higher permeability in a porous rock results in greater P-wave velocity dispersion. We utilize fullwaveform sonic data to study the relation of permeability and velocity dispersion of Stoneley waves. The sonic datasets were acquired from the Mallik gashydrate research wells in Mackenzie Delta, Northwest Territory, Canada. Velocities of Stoneley wave are measured using semblance analysis on low and high pass components, and the velocity difference is therefore velocity dispersion. Well logs from the same borehole are then investigated to produce cross plots of velocity dispersion, permeability, and porosity. The measurements show positive correlation between velocity dispersion and permeability. It is very common that Stoneley wave is much stronger and easier to identify than P or S wave in borehole sonic surveys. Our effort demonstrates that velocity dispersion of Stoneley wave is a potential indicator of in situ permeability. 2012 English 9781629937908 74th European Association of Geoscientists and Engineers Conference and Exhibition 2012 Incorporating SPE EUROPEC 2012: Responsibly Securing Natural Resources European Association of Geoscientists and Engineers, EAGE 1839-1843 China University of Petroleum, China; University of Toronto, Canada Petroleum reservoir engineering; Petroleum reservoir evaluation; Seismic waves; Shear waves; Velocity; Wave propagation; Well logging, Hydrocarbon exploration; P-wave velocity; Positive correlations; Potential indicators; Reservoir analysis; Semblance analysis; Velocity difference; Velocity dispersion, Dispersion (waves) https://www.scopus.com/inward/record.uri?eid=2-s2.0-84928193012&partnerID=40&md5=73f20f904054c9c9d8d99a9a12a991be cited By 0 L.F. Sun W. Pun B. Milkereit article cp-8-1287-2012 Frozen sediments from three cores bored in the permafrost surrounding the El'gygytgyn Impact Crater Lake have been studied for pollen, non-pollen palynomorphs, plant macrofossils and rhizopods. The palynological study of these cores contributes to a higher resolution of time intervals presented in a poor temporal resolution in the lacustrine sediments; namely the Allerød and succeeding periods. Moreover, the permafrost records better reflect local environmental changes, allowing a more reliable reconstruction of the local paleoenvironments. The new data confirm that shrub tundra with dwarf birch, shrub alder and willow dominated the lake surroundings during the Allerød warming. Younger Dryas pollen assemblages reflect abrupt changes to grass-sedge-herb dominated environments reflecting significantly drier and cooler climate. Low shrub tundra with dwarf birch and willow dominate the lake vicinity at the onset of the Holocene. The find of larch seeds indicate its local presence around 11 000 cal yr BP and, thus a northward shift of treeline by about 100 km during the early Holocene thermal optimum. Forest tundra with larch and shrub alder stands grew in the area during the early Holocene. After ca. 3500 cal yr BP similar-to-modern plant communities became common in the lake vicinity. © 2009 Author(s). 2012 English 18149324 10.5194/cp-8-1287-2012 Climate of the Past 8 1287-1300 Institute of Geology and Mineralogy, University of Cologne, Zülpicher Str. 49a, 50674, Cologne, Germany; Arctic and Antarctic Research Institute, Bering St. 38, 199397 St. Petersburg, Russian Federation; Alfred Wegener Institute for Polar and Marine Research, Department of Periglacial Research, Telegrafenberg A43, 14473 Potsdam, Germany; Faculty of Soil Science, Moscow State University, Vorobievy Gory, 119899 Moscow, Russian Federation; Senckenberg, Research Institute and Natural History Museum, Research Station for Quaternary Paleontology, Am Jakobskirchhof 4, 99423 Weimar, Germany 4 climate change; environmental change; Hypsithermal; paleoenvironment; permafrost; sediment core; temporal record; treeline; vegetation history, Chukchi; Elgygytgyn Lake; Russian Federation https://cp.copernicus.org/articles/8/1287/2012/ cited By 35 A. A. Andreev E. Morozova G. Fedorov L. Schirrmeister A. A. Bobrov F. Kienast G. Schwamborn article Liu2012169 A unique dissolution-reprecipitation zircon has been identified for the first time in a Qtz- and Phe-bearing eclogite from the drill hole CCSD-MH, southwestern Sulu UHP terrane by using laser Raman and cathodoluminescence (CL) imaging combined with trace-element analyses and U-Pb and Lu-Hf isotope data. Relic inherited domains of partially dissolved zircon show magmatic features and preserve mineral inclusions of Cpx+Pl+Qtz+Ap. Whereas newly formed zircons crystallized around or along cracks of the inherited (magmatic) domains and contain mineral inclusions of Coe+Grt+Omp+Phe+Ap typical for UHP metamorphism. In addition, primary fluid inclusions were identified in the coesite-bearing zircon domains, characterized by a single H 2O-phase or CO 2-H 2O-phase, indicating the presence of fluids during UHP conditions. Strongly dissolved inherited (magmatic) zircons yielded SHRIMP 206Pb/ 238U ages of 782-588Ma with an upper intercept age of 780±14Ma. New recrystallized or metamorphic zircons yielded consistent Triassic UHP ages around 238-225Ma with a weighted mean of 229.2±2.3Ma. Zircon trace element and Hf isotope compositions and mineral inclusions classify the protolith of the Sulu eclogite as an intermediate to mafic Neoproterozoic igneous rock, which was subducted to mantle depth and experienced UHP metamorphism in Middle Triassic times. The juvenile εHf (780Ma) value of+7.4±2.9 in inherited (magmatic) zircon points to a significant input from the depleted mantle to the Dabie-Sulu UHP terrane during Middle Neoproterozoic. New UHP zircon domains have low Lu/Hf, Th/U and significantly higher 176Hf/ 177Hf ratios than the inherited (magmatic) zircons, consistent with formation during recrystallization and fractionation of the Lu-Hf system during UHP metamorphism. © 2011 International Association for Gondwana Research. Article 2012 English 1342937X 10.1016/j.gr.2011.11.007 Gondwana Research 22 169 – 183 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84860884166&doi=10.1016%2fj.gr.2011.11.007&partnerID=40&md5=b06b61b5dd25ead3c9a9e88d050e777d Cited by: 34 Fulai Liu Axel Gerdes Pinghua Liu article He2012 We present an integrated chronology for the terrestrial Upper Cretaceous in East Asia based on high-resolution magnetostratigraphic results and detailed SIMS U-Pb zircon analyses of a continuous continental sedimentary sequence drilled from the Songliao Basin in northeast China. Correlation to the geomagnetic polarity timescale was achieved by combining magnetostratigraphic and SIMS U-Pb zircon geochronologic data, which suggest that the south core of the CCSD-SK-I sedimentary sequence spans from upper chron C34n to lower chron C33r. The age of the termination of the Cretaceous Normal Superchron (CNS) was estimated to be ∼83.4 Ma. Intervals of reverse geomagnetic field polarity of early Santonian age could be present during the late CNS. Two black shale layers at the base of Member 1 of the Qingshankou Formation and Member 2 of the Nenjiang Formation, which were previously interpreted as the products of lake anoxic events LAE1 and LAE2, have been well dated at 91.4 Ma and 83.7 Ma, respectively, by SIMS U-Pb zircon analyses of intercalated bentonite layers. However, the LAE1 and LAE2 identified here are not temporally correlated to the known oceanic anoxic events. Copyright 2012 by the American Geophysical Union. 2012 English 15252027 10.1029/2011GC003901 Geochemistry, Geophysics, Geosystems 13 Blackwell Publishing Ltd Key Laboratory of the Earth's Deep Interior, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China; State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China; College of Earth Sciences, Jilin University, Changchun 130061, China 2 Anoxic sediments; Geomagnetism; Lead; Sedimentology, Age determination; Anoxic events; Black shales; Cretaceous Normal Superchron; East Asia; Geomagnetic fields; Geomagnetic polarity; High resolution; Magnetostratigraphy; Northeast China; Oceanic Anoxic Event; Sedimentary sequence; Songliao basin; Time-scales; U-Pb zircon; Upper Cretaceous, Geochronology, anoxic conditions; bentonite; black shale; Cretaceous; geochronology; geomagnetic field; magnetostratigraphy; sedimentary sequence; uranium-lead dating, China; Songliao Basin https://www.scopus.com/inward/record.uri?eid=2-s2.0-84863012113&doi=10.1029%2f2011GC003901&partnerID=40&md5=c88fef5addfae346b0726340a4e17104 cited By 87 H. He C. Deng P. Wang Y. Pan R. Zhu article Ryberg20121341 A seismic reflection/refraction survey across the San Andreas fault near Parkfield, California, has refined our knowledge of the upper crustal structure of the central California Coast Ranges at the San Andreas Fault Observatory at Depth (SAFOD). The survey consisted of a 46-km-long line of seismographs (25-50 m spacing) and 63 explosions (25-200 kg; nominal spacing of 500 m, with some gaps). The traveltimes of refracted P and S waves from the explosions constitute independent data sets of relatively high quality that were inverted to produce P- and S-wave velocity models (V p, V s) along the profile, extending to as much as 5 km depth. The V p and V s models show a prominent lateral drop in velocities a few hundred metres northeast of SAFOD, between the drill hole and the San Andreas fault. The V p model shows particularly well a southwest-dipping velocity inversion beneath SAFOD, the top of which correlates with a fault penetrated by the drill hole that separates granitic rocks above from sedimentary rocks below. In addition to V p and V s models, a V p/V s model was derived. A V p/V s ratio lower than 1.73 is seen only at depth, in a narrow zone beginning at the target earthquakes for SAFOD and extending downward and northeastward into the North America Plate. Clusters in the parameter space spanned by V p/V s ratios and V p can be identified by two different methods, one more intuitive analytical method and one more abstract method based on neural network techniques. These clusters are correlated to different rock types, based on laboratory and in situ data. These clusters are remapped back into x-z plane along the profile. Prominent features mapped this way include Salinian granitic rocks beneath and west of SAFOD, and a body of sedimentary rocks faulted beneath these granitic rocks along what we and others interpret to be a branch of the Buzzard Canyon Fault (BCF) system. These sedimentary rocks extend from this fault to the San Andreas fault system. Unfortunately, our cluster analysis shows no significant discontinuity at the San Andreas fault, owing presumably to the fact that the San Andreas fault is located within sedimentary rocks having similar elastic properties. This paper is an attempt to 'downward' continue a geological map by geophysical means based on elastic properties of rock samples from the region. © 2012 The Authors Geophysical Journal International © 2012 RAS. 2012 English 0956540X 10.1111/j.1365-246X.2012.05585.x Geophysical Journal International 190 1341-1360 Helmholz-Zentrum Potsdam, Deutsches GeoForschungsZentrum GFZ, Telegrafenberg, 14473 Potsdam, Germany; Department of Geosciences, Virginia Tech, 4044 Derring Hall, Blacksburg, VA 24061, United States; U.S. Geological Survey, 345 Middlefield Road MS 977, Menlo Park, CA 94025-3591, United States; Institute of Geosciences, University of Jena, Burgweg 11, D-07749 Jena, Germany 3 Body waves; Continental margin; Controlled source; North America; Seismic tomography, Cluster analysis; Elasticity; Granite; Rock drills; Sedimentary rocks; Seismographs; Seismology; Shear waves; Strike-slip faults; Surveys; Transform faults, Structural geology, body wave; cluster analysis; continental margin; P-wave; S-wave; San Andreas Fault; seismic data; seismic reflection; seismic refraction; seismic source; seismic survey; seismic tomography; seismic velocity; seismograph; seismology; transform fault; upper crust, California; Coast Ranges; San Andreas; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-84865282849&doi=10.1111%2fj.1365-246X.2012.05585.x&partnerID=40&md5=9d718c69b2c15773e96d0f69ccce925e cited By 13 T. Ryberg J.A. Hole G.S. Fuis M.J. Rymer F. Bleibinhaus D. Stromeyer K. Bauer article Russell201268 The Towuti Drilling Project (TDP) is an international research program, whose goal is to understand long-term environmental and climatic change in the tropical western Pacific, the impacts of geological and environmental changes on the biological evolution of aquatic taxa, and the geomicrobiology and biogeochemistry of metal-rich, ultramafic-hosted lake sediments through the scientific drilling of Lake Towuti, southern Sulawesi, Indonesia. Lake Towuti is a large tectonic lake at the downstream end of the Malili lake system, a chain of five highly biodiverse lakes that are among the oldest lakes in Southeast Asia. In 2015 we carried out a scientific drilling program on Lake Towuti using the International Continental Scientific Drilling Program (ICDP) Deep Lakes Drilling System (DLDS). We recovered a total of ~ 1018m of core from 11 drilling sites with water depths ranging from 156 to 200 m. Recovery averaged 91.7 %, and the maximum drilling depth was 175m below the lake floor, penetrating the entire sedimentary infill of the basin. Initial data from core and borehole logging indicate that these cores record the evolution of a highly dynamic tectonic and limnological system, with clear indications of orbital-scale climate variability during the mid- to late Pleistocene. © Author(s) 2016. Conference paper 2012 English 18163459 10.2204/iodp.sd.14.11.2012 Scientific Drilling 21 Copernicus GmbH 68 – 71 14 Biology; Climate change; Drilling; Microbiology; Tectonics; Biological evolution; Climate variability; Continental scientific drillings; Environmental change; International researches; Limnological system; Scientific drilling; Tropical Western Pacific; Lakes https://www.scopus.com/inward/record.uri?eid=2-s2.0-84867796087&doi=10.2204%2fiodp.sd.14.11.2012&partnerID=40&md5=d2133bb13a3d2340d110012e9a439c50 Cited by: 14; All Open Access, Gold Open Access James Russell Satria Bijaksana article Perugini2012326 We present new experimental results on the study of the space and time modulation of compositional fields during chaotic mixing between mafic and felsic silicate melts. The experimental strategy was planned using numerical simulations performed using the experimental geometry. These mixing experiments were performed using a recently developed experimental apparatus, which is capable of mixing high-viscosity silicate melts at high temperatures and under precisely controlled conditions of fluid-dynamics and strain. The compositional variability produced by the mixing process was investigated both along linear analytical transects and on high-resolution 2D X-ray maps, covering the mixing patterns.Our results indicate that chaotic flow fields represent very powerful dynamics to blend silicate melts, even under laminar fluid dynamic conditions (Reynolds number ca. 10-7) and for dissimilar melts with high viscosity ratios (on the order of 103). The repetition of stretching and folding processes between the two melts induced a strong increase of contact interfaces thus favoring efficient chemical exchanges. As a result the initial mafic composition is no longer detectable in the mixing system after ca. 2h (i.e. the duration of the experiment). A further important result is the observation of highly non-linear patterns in inter-elemental plots produced by the onset of diffusive fractionation processes. This is contrary to common thinking that magma mixing should always produce linear trends between pairs of chemical elements.A new measure, the "concentration variance", is proposed to quantify chemical element mobility during the mixing process. This measure is statistically robust and can be quantitatively used to measure chemical element mobility independently of the geometry in which the compositional variation (i.e. transects, areas, etc.) is embedded or the local strain history of the mingling.Our results highlight concentration variance as a robust probe of the as yet poorly-understood processes involved in the common petrological process of magma mixing. © 2012 Elsevier B.V. 2012 English 00244937 10.1016/j.lithos.2012.09.010 Lithos 155 326-340 Department of Earth Sciences, University of Perugia, Italy; Department of Earth and Environmental Sciences, Ludwig-Maximilian-University, Germany computer simulation; experimental study; felsic rock; fluid dynamics; fractionation; high temperature; igneous intrusion; laminar flow; mafic rock; mixing; petrology; Reynolds number; silicate melt https://www.scopus.com/inward/record.uri?eid=2-s2.0-84869875621&doi=10.1016%2fj.lithos.2012.09.010&partnerID=40&md5=8aeb369f940fa82ebfc8d89444f5827b cited By 34 D. Perugini C.P. De Campos W. Ertel-Ingrisch D.B. Dingwell article Schreiber201261 Ancient Lake Ohrid is characterized by vertical (bathymetrical) zones within the lake, presumably promoting allopatric speciation due to barriers or parapatric speciation along gradients. Examples within the lake include the belt of Chara algae as well as the shell zone, both presumably impeding migrations of benthic invertebrates. Three potential cases of vertical differentiation leading to distinct depth forms have been reported for the gastropod subfamily Pyrgulinae (Caenogastropoda: Hydrobiidae): Ginaia munda ssp., Macedopyrgula spp. and Ochridopyrgulamacedonica ssp. Based on DNA data of the COI gene from a total of 145 specimens, this article aims at investigating the vertical differentiation within these depth forms and thus patterns of speciation in Lake Ohrid. An initial morphometric analysis showed a clear correlation of shell shape and collecting depth for Ginaia munda ssp. and Macedopyrgula spp. This morphological trend is largely reflected in the genetic structure of the respective taxa. The data presented here indicate the existence of strong gradients of abiotic and biotic factors in Lake Ohrid rather than distinct barriers. Therefore, parapatric speciation may be the predominant form of differentiation of benthic invertebrates in the lake. Incomplete lineage sorting, hybridization and phenotypic plasticity possibly caused by epigenetic mechanisms are discussed as possible reasons for the incongruence between geno- and phenotype observed in few specimens of Ginaia munda ssp. and Macedopyrgula spp. For the third taxon, Ochridopyrgulamacedonica ssp., morphometric and genetic analyses revealed only weak support for the previously proposed depth forms. However, a horizontal differentiation of lake and spring populations was revealed instead, and parapatric and allopatric differentiations are discussed in this taxon. © 2011 Springer Science+Business Media B.V. Article 2012 English 15735117 10.1007/s10750-011-0864-4 Hydrobiologia 682 61 – 73 1 Lake Ohrid; algae; Caenogastropoda; Chara; Gastropoda; Hydrobiidae; Invertebrata; Lonchocarpus glaucifolius; alga; allopatry; barrier (equipment); bathymetric survey; benthos; gastropod; genetic analysis; genetic structure; morphometry; parapatry; phenotypic plasticity; phylogeography; speciation (biology) https://www.scopus.com/inward/record.uri?eid=2-s2.0-84856214332&doi=10.1007%2fs10750-011-0864-4&partnerID=40&md5=622029f5f2f8e8830a1592a8ce0db895 Cited by: 28 Kirstin Schreiber Torsten Hauffe Christian Albrecht Thomas Wilke article Schmitt20121017 Hotspot: The Snake River Geothermal Drilling Project was undertaken to better understand the geothermal systems in three locations across the Snake River Plain with varying geological and hydrological structure. An extensive series of standard and specialized geophysical logs were obtained in each of the wells. Hydrogen-index neutron and γ-γ density logs employing active sources were deployed through the drill string, and although not fully calibrated for such a situation do provide semi-quantitative information related to the 'stratigraphy' of the basalt flows and on the existence of alteration minerals. Electrical resistivity logs highlight the existence of some fracture and mineralized zones. Magnetic susceptibility together with the vector magnetic field measurements display substantial variations that, in combination with laboratory measurements, may provide a tool for tracking magnetic field reversals along the borehole. Full waveform sonic logs highlight the variations in compressional and shear velocity along the borehole. These, together with the high resolution borehole seismic measurements display changes with depth that are not yet understood. The borehole seismic measurements indicate that seismic arrivals are obtained at depth in the formations and that strong seismic reflections are produced at lithological contacts seen in the corresponding core logging. Finally, oriented ultrasonic borehole televiewer images were obtained over most of the wells and these correlate well with the nearly 6 km of core obtained. This good image log to core correlations, particularly with regards to drilling induced breakouts and tensile borehole and core fractures will allow for confident estimates of stress directions and or placing constraints on stress magnitudes. Such correlations will be used to orient in core orientation giving information useful in hydrological assessments, paleomagnetic dating, and structural volcanology. 2012 English 9781622764341 01935933 Transactions - Geothermal Resources Council 36 2 1017-1022 Institute for Geophysical Research, Dept. of Physics, University of Alberta, Edmonton, AB, Canada; Center for Geophysical Investigation of the Shallow Subsurface, Boise State University, Boise, ID, United States; Department of Geology, Utah State University, Logan, UT, United States; ICDP Operational Support Group, Deutsches GeoForschungZentrum GFZ, Potsdam, Germany; United States Geological Survey, Menlo Park, CA, United States Electrical resistivity; Geophysical logging; Hydrological assessment; Laboratory measurements; Magnetic field reversal; Snake river plains; Substantial variations; Vertical seismic profiles, Electric conductivity; Electric logging; Fracture; Geothermal fields; Geothermal wells; Landforms; Lithology; Magnetic susceptibility; Radioactivity logging; Rivers; Seismology; Stratigraphy; Stresses; Structural geology, Boreholes https://www.scopus.com/inward/record.uri?eid=2-s2.0-84876249897&partnerID=40&md5=ae01f8c1773fa469b24c606824e1f013 cited By 7 L.M. Liberty J.E. Kessler R. Kofman R. Bishop J.W. Shervais J.P. Evans D.E. Champion book Keller2012759 After three decades of nearly unchallenged wisdom that a large impact (Chicxulub) on Yucatan caused the end-Cretaceous mass extinction, this theory is facing its most serious challenge from the Chicxulub impact itself, as based on evidence in Texas and Mexico and from Deccan volcanism in India. Data generated from over 150 Cretaceous-Tertiary (KT) boundary sequences to date make it clear that the long-held belief in the Chicxulub impact as the sole or even major contributor to the KT mass extinction is not supported by evidence. The stratigraphic position of the Chicxulub impact ejecta spherules in NE Mexico and Texas and the impact breccia within the crater on Yucatan demonstrate that this impact predates the KTB by about 300,000 years. Planktic foraminiferal and stable isotope analyses across the primary impact ejecta layer reveal that not a single species went extinct as a result of this impact and no significant environmental changes could be determined. The catastrophic effects of this impact have been vastly overestimated. In contrast, recent advances in Deccan volcanic studies indicate three volcanic phases with the smallest at 67.5 Ma, the main phase at the end of the Maastrichtian (C29r), and the third phase in the early Danian C29r/C29n transition (Chenet et al. 2007). The main phase of eruptions occurred rapidly, was marked by the longest lava flows spanning 1500 km across India, and ended coincident with the KT boundary. The KT mass extinction may have been caused by these rapid and massive Deccan lava and gas eruptions that account for ~80% of the entire 3500 m thick Deccan lava pile. © Springer Science+Business Media B.V. 2012. 2012 10.1007/978-90-481-3428-1_25 Earth and Life: Global Biodiversity, Extinction Intervals and Biogeographic Perturbations Through Time 759-793 Department of Geosciences, Princeton University, Princeton, NJ 08544, United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-85012096265&doi=10.1007%2f978-90-481-3428-1_25&partnerID=40&md5=4088e6b0b3e8b3205108a43dcb0de6a3 cited By 32 G. Keller article Schijns2012541 Seismic velocity anisotropy measurements are made of a fractured metamorphic formation from the 2.5-km-deep International Continental Scientific Drilling Programme (ICDP) borehole in Outokumpu, Finland. Three component walk-away vertical seismic profile (VSP) measurements are made along two source-line azimuths at three receiver depths (1000, 1750 and 2500 m) and incidence angle-dependent qP- and qS-wave velocities are extracted with a τ-p method. The highest qP-wave anisotropy, 13.6 per cent (v fast= 6160 m s -1, v slow= 5370 m s -1), is measured between 1000- and 1750-m depth, with anisotropy of up to 9.4 per cent (v fast= 6090 m s -1, v slow= 5540 m s -1) measured between 1750 and 2500 m depth. The top ∼1300 m of the region is composed of a homogeneous, strongly intrinsically anisotropic biotite-rich schist, and is sampled by the shallowest walk-away profile. Anisotropy of up to 11.1 per cent (v fast= 5950 m s -1, v slow= 5320 m s -1) is measured by the walk-away VSP between 50 and 1000 m depth, along with shear wave splitting averaging 5 per cent (180 m s -1). Laboratory-derived intrinsic anisotropy of the schist cannot by itself explain the degree or orientation of the anisotropy measured in the walk-away VSPs, however, a model which modifies the intrinsic stiffnesses by the inclusion of a single set of dipping, aligned cracks allows the observed in situ velocities to be reproduced. Forward modelling of the qP-wave walk-away VSP measurements from 50 to 1000 m depth is undertaken using an effective medium model to develop a 3-D velocity model of this region. An orthorhombic medium is used to represent the intrinsic anisotropy of the biotite-rich schist, and a single set of aligned cracks is added to give a bulk elastic stiffness. The resulting model predicts the schist to have an overall anisotropy of 16.8 per cent, with qP-wave velocities of up to 6315 m s -1. The accuracy of the model is assessed through its fit to the walk-away VSP measurements as well as a comparison to known geology of the region. © 2012 The Authors Geophysical Journal International © 2012 RAS. Article 2012 English 1365246X 10.1111/j.1365-246X.2012.05358.x Geophysical Journal International 189 541 – 553 1 Finland; Outokumpu; Pohjois-Karjala; Anisotropy; Cracks; Mica; Seismology; Stiffness; Three dimensional; Velocity; Angle-dependent; Cratons; Downholes; Effective medium model; Elastic stiffness; Finland; Forward modelling; In-situ; Intrinsic anisotropy; Scientific drilling; Seismic anisotropy; Seismic velocities; Shear wave splitting; Three component; Upper crust; Velocity model; Vertical seismic profiles; accuracy assessment; biotite; borehole; crystallization; forward modeling; fracture zone; homogeneity; in situ measurement; observational method; P-wave; S-wave; seismic anisotropy; seismic velocity; stiffness; three-dimensional modeling; upper crust; wave splitting; well logging; Seismic prospecting https://www.scopus.com/inward/record.uri?eid=2-s2.0-84858620250&doi=10.1111%2fj.1365-246X.2012.05358.x&partnerID=40&md5=77464191488347b5075a50fc3d73bde2 Cited by: 25; All Open Access, Bronze Open Access Heather Schijns Douglas R. Schmitt Pekka J. Heikkinen Ilmo T. Kukkonen article Stockhecke2012148 The varved sediments of Lake Van provide a high-quality continental archive of seasonal to decadal-scale climate variability. In order to read the natural record, modern varve formation was studied on the basis of (1) remotely-sensed total suspended-matter (TSM rs) concentrations; (2) time-series of particle flux and water temperatures; and (3) turbidity, temperature, and oxygen profiles. TSM rs, validated by contemporaneous water-column sampling, shows great temporal and lateral variations (whitings and turbidity plumes). From 2006 to 2009, sequential sediment traps recorded high particle fluxes during spring and fall, medium fluxes during summer, and almost zero flux during winter. The mean total mass flux of 403mgm -2day -1 comprised 33% (seasonally up to 67%) calcium carbonate, 7% aquatic organic matter, 6% biogenic opal, and 54% detrital minerals. The CaCO 3 fluxes are controlled by river discharge (precipitation and snowmelt) during spring, by high productivity during summer, and by river discharge (precipitation before snowfall starts) and mixing during fall. In November 2007, an anomalously high CaCO 3 flux occurred as a result of a warm water surface supersaturated with calcite coinciding with an anomalous runoff event. The results demonstrate that the couplets of light and dark laminae in the short sediment cores are true varves representing spring-summer-fall and winter conditions, respectively. Consequently, varve formation can be linked to the seasonal climate pattern, providing a calibration that can be used to interpret the partially varved paleo-record of Lake Van and related environmental processes. © 2012 Elsevier B.V. 2012 English 00310182 10.1016/j.palaeo.2012.03.022 Palaeogeography, Palaeoclimatology, Palaeoecology 333-334 148-159 Eawag, Swiss Federal Institute of Aquatic Science and Technology, Department of Surface Waters Research and Management, Ueberlandstrasse 133, P. O. Box 611, 8600 Dübendorf, Switzerland; Yüzüncü Yil Üniversitesi, Mühendislik-Mimarlik Fakültesi, Jeoloji Mühendisliǧi Bölumu 65080, Van, Turkey; Remote Sensing Laboratories, Department of Geography, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland calcium carbonate; concentration (composition); continental shelf; decadal variation; lacustrine deposit; oxygen; paleoenvironment; precipitation (climatology); remote sensing; river discharge; runoff; satellite data; sediment chemistry; sediment core; sediment trap; snowmelt; suspended particulate matter; time series; turbidity; water column; water temperature, Lake Van; Turkey https://www.scopus.com/inward/record.uri?eid=2-s2.0-84860457518&doi=10.1016%2fj.palaeo.2012.03.022&partnerID=40&md5=459da20e04d0697ef86c933cb4c6c66d cited By 46 M. Stockhecke F.S. Anselmetti A.F. Meydan D. Odermatt M. Sturm article Richter20121 Editorial 2012 English 10406182 10.1016/j.quaint.2012.06.009 Quaternary International 274 1 – 4 Homo sapiens https://www.scopus.com/inward/record.uri?eid=2-s2.0-84866002240&doi=10.1016%2fj.quaint.2012.06.009&partnerID=40&md5=0f55b448d7c3ffe8918b035d8f21ac2e Cited by: 18; All Open Access, Green Open Access Jürgen Richter Martin Melles Frank Schäbitz article Lin2025 Article 2012 Lithologic Reservoirs 24 38-42 06 J. Guo X. Wu J. Pan D. Wei J. Fu article Dubreuil-Boisclair20121076 Gas hydrates located offshore and onshore beneath thick permafrost areas constitute one of the largest untapped natural gas resources. Yet, gas hydrate in place (GHIP) estimation at the scale of a field is not common in the scientific literature but is required to realistically assess the economical potential of specific accumulations. Progress in the last decade in Alaska and Canada has shown that gas hydrate accumulations beneath thick permafrost can be mapped at depth using conventional seismic attributes (Inks et al., 2009; Riedel et al. 2009). To evaluate the economic potential of gas hydrates in this environment, a test site at Mallik, Northwest Territories, Canada, was extensively surveyed (three-dimensional seismic, full set of logs in two wells, etc.) and a production test was realized in high gas-hydrate horizons. At Mallik, high P- and S-wave velocities, high acoustic impedances, and strong seismic amplitude reflections were all linked to sand-rich sediments with a high saturation of gas hydrates (Bellefleur et al. 2006; Riedel et al.). This relationship provides a strong basis for an integrated data characterization of this gas hydrate deposit. © 2012 Society of Exploration Geophysicists. 2012 English 1070485X 10.1190/tle31091076.1 Leading Edge 31 Society of Exploration Geophysicists 1076-1081 INRS-ETE, Canada; Geological Survey of Canada, Canada; Ecole Polytechnique de Montréal, Canada 9 Acoustic impedance; Energy resources; Gases; Hydration; Natural gas; Natural gas deposits; Offshore oil well production; Permafrost; Petroleum deposits; Seismic prospecting; Seismology; Shear waves; Stochastic systems, Connectivity analysis; Economic potentials; Hydrate accumulations; Natural gas resources; P- and S-wave velocities; Scientific literature; Seismic amplitudes; Volume estimations, Gas hydrates, connectivity; estimation method; gas hydrate; natural gas; permafrost; S-wave; stochasticity, Alaska; Canada; Northwest Territories; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-84872028634&doi=10.1190%2ftle31091076.1&partnerID=40&md5=4247e306f1479687f167ed19d2a86ae7 cited By 2 C. Dubreuil-Boisclair E. Gloaguen G. Bellefleur D. Marcotte conference Dubreuil-Boisclair2012496 This study focuses on the Mallik gas hydrate field, in the Northwest Territories, where 3D acoustic impedance and well log data from two wells are available. Firstly, collocated log data are used to infer the statistical relation between acoustic impedance and gas hydrate grade (product of saturation and porosity). Secondly, adapted stochastic Bayesian simulation is applied to generate multiple 3D models of gas hydrate grade fields integrating log data and lateral variability of 3D acoustic impedance. A statistical analysis of these scenarios allows the quantification of the in-place gas volumes. The simulation approach also allows estimating the uncertainty on these volumes. Then, connectivity analysis is computed on the three gas hydrate layers based on different grade cutoffs. The upper gas hydrate layers (zones A & B) show low connectivity and low grades. The deeper gas hydrate layer (Zone C) presents the highest connectivity that reaches the limit of the studied 3D grid, suggesting an even larger connected area of high gas hydrate grades. © 2012 SEG. 2012 English 9781622769452 10.1190/segam2012-0033.1 Society of Exploration Geophysicists International Exposition and 82nd Annual Meeting 2012, SEG 2012 Society of Exploration Geophysicists 496-501 INRS-ETE, Canada; Geological Survey, Canada; Ecole Polytechnique de Montréal, Canada Acoustic fields; Acoustic impedance; Gases; Geophysical prospecting; Hydration; Petroleum prospecting; Stochastic models; Stochastic systems; Uncertainty analysis; Well logging, Bayesian simulation; Connectivity analysis; Different grades; Gas hydrate reservoir; Simulation approach; Statistical relations; Volume estimations; Well log data, Gas hydrates https://www.scopus.com/inward/record.uri?eid=2-s2.0-85059181952&doi=10.1190%2fsegam2012-0033.1&partnerID=40&md5=252e1f056dcd632f7dd66373bef193b9 cited By 0 C. Dubreuil-Boisclair E. Gloaguen G. Bellefleur D. Marcotte article Pollitz20121348 A series of near-surface chemical explosions conducted at the San Andreas Fault Observatory at Depth (SAFOD) main hole were recorded by highfrequency downhole receiver arrays in April 2005. These seismic recordings at depths ranging from the surface to 2.3 km constrain the shallow velocity and attenuation structure as well as the first-order characteristics of the source. Forward modeling of the explosions indicates that a source consisting of combined explosion, delayed implosion, and second-order moment-tensor components (corresponding to a distribution of vertical shear dislocations in the rock directly above the explosion) is sufficient to characterize the generated seismic wave fields to first order. Grid searches over source parameters controlling the nonexplosive components allow for the quantification of distributed vertical shear above the source and the estimation of the moment and time delay of the implosive component relative to the explosion. An estimated implosive to explosive moment ratio of 0.34 to 0.43 indicates a net static moment and positive macroscopic volume change. 2012 English 00371106 10.1785/0120110201 Bulletin of the Seismological Society of America 102 1348-1360 U.S. Geological Survey, 345 Middlefield Rd. MS 977, Menlo Park, CA 94025, United States 4 Chemical explosions; Downholes; First-order; Forward modeling; Grid search; High frequency HF; Moment ratio; Near-surface; Receiver array; San Andreas fault; Second orders; Seismic recording; Source characterization; Source parameters; Static moment; Vertical shear; Volume change, Strike-slip faults, Explosions, moment tensor; nuclear explosion; seismic attenuation; seismic velocity; seismic wave; source parameters https://www.scopus.com/inward/record.uri?eid=2-s2.0-84865044400&doi=10.1785%2f0120110201&partnerID=40&md5=5c393e3bb5cd561a752cf045bcb39cd0 cited By 3 F.F. Pollitz J. Rubinstein W. Ellsworth article Xiao201221 Major ion compositions were analyzed in 65 groundwater samples to decipher water quality, solute geochemistry and sources of groundwater within the Qinghai Lake catchment, NE Tibetan Plateau. Groundwaters were slightly alkaline with pH varying from 7.2 to 8.7. The total dissolved solids (TDS) varied over two orders of magnitude from fresh (88%) to brackish (12%) with a mean value of 672mg/L, higher than river waters within the Qinghai Lake catchment and river waters draining the Himalayas and the southeastern Tibetan Plateau. Most of the samples, approximately 80%, were the Ca 2+-Mg 2+-HCO3- type and suitable for drinking and irrigation. Some of the Lakeside, the Buha and the Qinghai Lake water were the Na +-Cl - type and not suitable for drinking and irrigation. Water quality of Hargai and Shaliu samples was better than the others. Rock weathering, ion exchange and precipitation are the major geochemical processes responsible for the solutes in the groundwater within the Qinghai Lake catchment. Anthropogenic input to the groundwater is minor. The forward models on the input of groundwaters from various sources showed that the contributions were 40.1% for carbonate weathering, 29.0% for evaporite dissolution, 16.8% for atmospheric input and 14.1% for silicate weathering of the total dissolved cations for the whole catchment. Evaporite dissolution was dominating in the Lakeside, the Buha and the Daotang samples, contributing 15.3-45.9%, 20.4-61.1% and 21.3-63.9% of the total dissolved cations, respectively. Carbonate weathering was dominated in the Shaliu and the Hargai samples, contributing 23.9-71.7% and 31.8-95.4% of the total dissolved cations, respectively. The result also demonstrated that carbonate weathering had higher contribution to the groundwaters than silicate weathering. © 2012 Elsevier Ltd. Article 2012 English 13679120 10.1016/j.jseaes.2012.02.006 Journal of Asian Earth Sciences 52 21 – 30 China; Himalayas; Qinghai; Qinghai-Xizang Plateau; catchment; dissolution; groundwater; ion exchange; ionic composition; river water; solute; water quality; weathering https://www.scopus.com/inward/record.uri?eid=2-s2.0-84860483091&doi=10.1016%2fj.jseaes.2012.02.006&partnerID=40&md5=47851048910a3429114320e950925e39 Cited by: 55 Jun Xiao Zhang Dong Jin Fei Zhang Jin Wang article Lewis2012626 We use cross-correlation of seismic noise recorded at stations in the San Andreas Fault Observatory at Depth (SAFOD) pilot hole to extract P and S waves and measure S-wave anisotropy on the horizontal components. The data are recorded at seven three-component stations at depths from 1857 to 2097 m in the pilot hole. In late September and early 2004 October drilling noise underneath the stations generated propagating waves, which were absent in the rest of October. Estimates of the P- and S-wave velocities from the cross-correlations, on the vertical and horizontal components, respectively, are consistent with velocity measurements taken directly in the borehole. We observe polarization of the S wave, with a fast polarization direction of 120°-130° that is 4 per cent faster than the slow direction. Cross-correlation of the seismic noise can accurately determine S-wave anisotropy. © 2011 The Authors Geophysical Journal International © 2011 RAS. 2012 English 0956540X 10.1111/j.1365-246X.2011.05285.x Geophysical Journal International 188 626-630 Scripps Institution of Oceanography, La Jolla, CA 92093, United States; Earthworks Environment and Resources Ltd, Salisbury, SP2 7NU, United Kingdom 2 Body waves; Cross correlations; Drilling noise; P- and S-waves; Pilot holes; Polarization direction; S-wave velocity; S-waves; San Andreas Fault; Seismic anisotropy; Seismic noise; Shear-wave anisotropy; Three-component, Anisotropy; Interferometry; Polarization; Seismology; Shear waves; Velocity measurement, Shear flow, borehole; correlation; interferometry; P-wave; S-wave; San Andreas Fault; seismic anisotropy; seismic noise; wave propagation; wave velocity, California; Parkfield; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-84855441215&doi=10.1111%2fj.1365-246X.2011.05285.x&partnerID=40&md5=54bbb290a4344058c1fe69e5fc7d2982 cited By 6 M.A. Lewis P. Gerstoft article Hainzl2012271 Two recent major swarms in Western Bohemia occurred in the years 2000 and 2008 within almost the same portion of a fault close to Novy Kostel. Previous analysis of the year 2000 earthquake swarm revealed that fluid intrusion seemed to initiate the activity whereas stress redistribution by the individual swarm earthquakes played a major role in the further swarm evolution. Here we analyse the new swarm, which occurred in the year 2008, with regard to its correlation to the previous swarm as well its spatiotemporal migration patterns. We find that (i) the main part of the year 2008 activity ruptured fault patches adjacent to the main activity of the swarm 2000, but that also (ii) a significant overlap exists where earthquakes occurred in patches in which stress had been already released by precursory events; (iii) the activity shows a clear migration which can be described by a 1-D (in up-dip direction) diffusion process; (iv) the migration pattern can be equally well explained by a hydrofracture growth, which additionally explains the faster migration in up-dip compared to the down-dip direction as well as the maximum up-dip extension of the activity. We use these observations to estimate the underlying fluid pressure change in two different ways: First, we calculate the stress changes induced by precursory events at the location of each swarm earthquake assuming that observed stress deficits had to be compensated by pore pressure increases; and secondly, we estimate the fluid overpressure by fitting a hydrofracture model to the asymmetric seismicity patterns. Both independent methods indicate that the fluid pressure increase was initially up to 30 MPa. © 2012 The Authors Geophysical Journal International © 2012 RAS. Article 2012 English 1365246X 10.1111/j.1365-246X.2012.05610.x Geophysical Journal International 191 271 – 281 1 Bohemia; Czech Republic; Diffusion in liquids; Estimation; Faulting; Diffusion process; Earthquake dynamics; Earthquake source; Earthquake swarms; Fluid pressures; Hydro-fracture; Migration patterns; Overpressure; Pressure increase; Seismicity pattern; Stress changes; Stress redistribution; earthquake precursor; earthquake swarm; fault; fluid pressure; fracture; geostatistics; seismic migration; seismic source; seismicity; seismology; Earthquakes https://www.scopus.com/inward/record.uri?eid=2-s2.0-84866418087&doi=10.1111%2fj.1365-246X.2012.05610.x&partnerID=40&md5=8b6aea5945b37654c079243b8a9acc4d Cited by: 66; All Open Access, Bronze Open Access, Green Open Access S. Hainzl T. Fischer T. Dahm article hedin_seismic_2012 A 36 kilometer long high resolution 2D seismic reflection profile was acquired in the summer of 2010 to be used in the planning of the COSC (Collisional Orogeny in the Scandinavian Caledonides) Deep Drilling Project. Two fully cored boreholes, each to c. 2.5 km depth, are planned for the Åre-Mörsil area of west-central Sweden in order to increase our understanding of orogenic processes and, in particular, the tectonic evolution of the Scandinavian Caledonides. Besides providing important sub-surface structural information in the vicinity of the potential drill sites, the seismic profile also provides detailed, high resolution images previously not available for the uppermost few kilometers in the region. The subsurface is highly reflective and very complex down to at least 9 km depth (the limit of decoded data) with clear reflections spanning the entire length of the profile. Correlation with previous regional reflection seismic and magnetotelluric surveys has been achieved by acquisition of a short (7 km) connecting profile. A clearly defined reflection, present in the new profile at depths between c. 2.5 km in the east and c. 4.5 km in the west and with an average westwards dip of c. 3.5°, apparently defines the base of the Lower Allochthon. Closer to the Caledonian front, this sole thrust overlies the Cambrian alum shale formation, which rests unconformably on the autochthonous Precambrian crystalline basement. The latter is remarkable for its deep internal reflectivity which is probably related to mafic intrusions in a dominantly granitic host-rock; their deformation may be of both Caledonian and older (e.g. Sveconorwegian) age. The new high resolution seismic data provide the basis for locating the first borehole in the Seve Nappe Complex. They also demonstrate that the second hole, designed to penetrate the Caledonian basement, will have to be located further east than was originally planned. 2012 jul 0040-1951 10.1016/j.tecto.2012.05.026 Tectonophysics 554–557 30--41 Reflection seismic, Collisional orogeny, Borehole, Migration, Continental Scientific Drilling, Scandinavian Caledonides http://www.sciencedirect.com/science/article/pii/S0040195112003174 00000 P. Hedin C. Juhlin D. G. Gee conference Bellefleur2012560 The Mackenzie Delta in Canada's Northwest Territories hosts many permafrost-related gas hydrate accumulations that were indirectly discovered or inferred from conventional hydrocarbon exploration programs. In particular, gas hydrate intervals characterized with high saturation show high resistivity and high P- and S-wave velocity on well-log data, and are typically found in sand-rich horizons. As demonstrated at the Mallik site, the velocity contrast between highly saturated gas hydrate-bearing sediments and unconsolidated water-bearing sediments is significant and allows their detection with seismic data. Here, we use 2D and 3D seismic reflection data acquired by industry on Richards Island to map and characterize gas hydrate accumulations beneath a thick permafrost area of the Mackenzie Delta. Specifically, we show new seismic evidences of gas hydrate accumulations near YaYa, Ivik and Umiak. The presence of gas hydrate was previously inferred from well-log data in several boreholes located in those areas. All seismic data were re-processed following an AVO-friendly flow that preserved relative amplitude relationships. On such data, the strong acoustic impedance of gas hydrate produces strong amplitude seismic reflections. The seismic signature of gas hydrates is confirmed by seismic-to-well correlation in areas where boreholes are available. Results indicate that gas hydrate accumulations occur in structurally-controlled plays typical of conventional oil and gas traps found in this area, and further demonstrate that gas hydrates are part of the regional petroleum system. Copyright 2012, Offshore Technology Conference. 2012 English 9781627482899 10.4043/23767-ms Society of Petroleum Engineers - Arctic Technology Conference 2012 2 Society of Petroleum Engineers 560-569 Geological Survey of Canada, Canada Acoustic impedance; Aquifers; Boreholes; Gases; Gasoline; Hydration; Oil well logging; Permafrost; Petroleum prospecting; Seismic prospecting; Seismic response; Seismic waves; Shear waves; Wave propagation; Well logging, Conventional hydrocarbons; Conventional oil and gas; Hydrate accumulations; P- and S-wave velocities; Relative amplitude; Seismic reflections; Seismic signatures; Velocity contrasts, Gas hydrates https://www.scopus.com/inward/record.uri?eid=2-s2.0-84883406245&doi=10.4043%2f23767-ms&partnerID=40&md5=92229525f55da6c7efc1595b5ed11ee6 cited By 0 G. Bellefleur M. Riedel T. Brent article Gebhardt20121087 Maar lake Laguna Potrok Aike is located north of the Strait of Magellan (south-eastern Patagonia). Seismic reflection profiles revealed a highly dynamic palaeoclimate history. Dunes were identified in the eastern part of the lake at approximately 30 to 80m below the lake floor, overlying older lacustrine strata, and suggest that the region experienced dry conditions probably combined with strong westerly winds. It is quite likely that this can be linked to a major dust event recorded in the Antarctic ice cores during Marine Isotope Stage 4. The dunes are overlain by a series of palaeo-shorelines indicating a stepwise water-level evolution of a new lake established after this dry period, and thus a change towards wetter conditions. After the initial, rapid and stepwise lake-level rise, the basin became deeper and wider, and sediments deposited on the lake shoulder at approximately 33m below present-day lake level point towards a long period of lake-level highstand between roughly 53·5kacal. bp and 30kacal. bp with a maximum lake level some 200m higher than the desiccation horizon. This highstand was then followed by a regressional phase of uncertain age, although it must have happened some time between approximately 30kacal. bp and 6750yrscal. bp. Dryer conditions during the Mid-Holocene are evidenced by a dropping lake level, resulting in a basin-wide erosional unconformity on the lake shoulder. A second stepwise transgression between ca 5·8 to 5·4kacal. bp and ca 4·7 to 4kacal. bp with palaeo-shorelines deposited on the lake shoulder unconformity again indicates a change towards wetter conditions. © 2011 The Authors. Journal compilation © 2011 International Association of Sedimentologists. Article 2012 10.1111/j.1365-3091.2011.01296.x Sedimentology 59 1087 – 1100 3 Argentina; Laguna Potrok Aike; Magellan Strait; Patagonia; Santa Cruz [Argentina]; Anoxic sediments; Climate change; Glacial geology; Isotopes; Seismic waves; Argentina; ICDP project PASADO; Laguna potrok aike; Lake-level variations; Patagonia; Seismic reflection profiles; climate variation; desiccation; dune; ice core; lacustrine deposit; lake level; marine isotope stage; paleoclimate; sedimentation; seismic reflection; shoreline; transgression; unconformity; water level; Lakes https://www.scopus.com/inward/record.uri?eid=2-s2.0-84858705630&doi=10.1111%2fj.1365-3091.2011.01296.x&partnerID=40&md5=f3184194f141f7ebb24a6fb746c5d539 Cited by: 23 Andrea Catalina Gebhardt Christian Ohlendorf Marc De Batist Flavio S. Anselmetti Daniel Ariztegui Pierre Kliem Stefan Wastegård Bernd Zolitschka article Wagner2012112 Hydro-acoustic surveys and coring campaigns at Lake Prespa were carried out between 2007 and 2009. This paper presents hydro-acoustic profiles and provide lithological and chronostratigraphical information from three up to 15.75 m long sediment sequences from the Macedonian side of the lake. The sediment sequences comprise glacial and interglacial sediments likely deposited from the end of Marine Isotope Stage (MIS) 5 to present day. The information implies a distinct change of sedimentation patterns at the Pleistocene/Holocene transition and the establishment of a relatively strong Holocene current system and deposition of channel-related contourite drift in Lake Prespa. Potential causes for the establishment of this current during the Holocene include significant lake level change, reduced winter ice cover, and/or higher aeolian activity. © 2012 Elsevier Ltd and INQUA. Article 2012 English 10406182 10.1016/j.quaint.2012.02.016 Quaternary International 274 112 – 121 Lake Mikri Prespa; chronostratigraphy; contourite; drift behavior; glacial deposit; Holocene; ice cover; interglacial; lake level; lithology; marine isotope stage; Pleistocene; sediment core; sedimentary sequence; sedimentation https://www.scopus.com/inward/record.uri?eid=2-s2.0-84865956830&doi=10.1016%2fj.quaint.2012.02.016&partnerID=40&md5=b7a9cb7c9eb54ac8c96ef20303cc443d Cited by: 29 Bernd Wagner Anne Aufgebauer Hendrik Vogel Giovanni Zanchetta Roberto Sulpizio Magret Damaschke article Almeev20121837 The phase relations have been investigated experimentally at 200 and 500 MPa as a function of water activity for one of the least evolved (Indian Batt Rhyolite) and of a more evolved rhyolite composition (Cougar Point Tuff XV) from the 12·8-8·1 Ma Bruneau-Jarbidge eruptive center of the Yellowstone hotspot. Particular priority was given to accurate determination of the water content of the quenched glasses using infrared spectroscopic techniques. Comparison of the composition of natural and experimentally synthesized phases confirms that high temperatures (&gt;900°C) and extremely low melt water contents (&lt;1·5 wt % H. 2O) are required to reproduce the natural mineral assemblages. In melts containing ∼0·5-1·5 wt % H. 2O, the liquidus phase is clinopyroxene (excluding Fe-Ti oxides, which are strongly dependent on fO. 2), and the liquidus temperature of the more evolved Cougar Point Tuff sample (BJR; ∼940-1000°C) is at least 30°C lower than that of the Indian Batt Rhyolite lava sample (IBR2; 970-1030°C). For the composition BJR, the comparison of the compositions of the natural and experimental glasses indicates a pre-eruptive temperature of at least 900°C. The composition of clinopyroxene and pigeonite pairs can be reproduced only for water contents below 1·5 wt % H. 2O at 900°C, or lower water contents if the temperature is higher. For the composition IBR2, a minimum temperature of 920°C is necessary to reproduce the main phases at 200 and 500 MPa. At 200 MPa, the pre-eruptive water content of the melt is constrained in the range 0·7-1·3 wt % at 950°C and 0·3-1·0 wt % at 1000°C. At 500 MPa, the pre-eruptive temperatures are slightly higher (by ∼30-50°C) for the same ranges of water concentration. The experimental results are used to explore possible proxies to constrain the depth of magma storage. The crystallization sequence of tectosilicates is strongly dependent on pressure between 200 and 500 MPa. In addition, the normative Qtz-Ab-Or contents of glasses quenched from melts coexisting with quartz, sanidine and plagioclase depend on pressure and melt water content, assuming that the normative Qtz and Ab/Or content of such melts is mainly dependent on pressure and water activity, respectively. The combination of results from the phase equilibria and from the composition of glasses indicates that the depth of magma storage for the IBR2 and BJR compositions may be in the range 300-400 MPa (∼≤13 km) and 200-300 MPa (∼≤10 km), respectively. © The Author 2012. Published by Oxford University Press. All rights reserved. 2012 English 00223530 10.1093/petrology/egs035 Journal of Petrology 53 1837-1866 Institute of Mineralogy, Leibniz University of Hannover, Callinstraße 3, 30167 Hannover, Germany; Department of Geology and Geophysics, University of Utah, Salt Lake City, UT 84112-011, United States 9 concentration (composition); crystallization; experimental study; high temperature; hot spot; lava; magma; phase equilibrium; rhyolite; tectosilicate; volcanic eruption; water content, Idaho; Snake River Plain; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-84865577284&doi=10.1093%2fpetrology%2fegs035&partnerID=40&md5=495cd1ba7506bb8631c3b28537f07b69 cited By 56 R.R. Almeev T. Bolte B.P. Nash F. Holtz M. Erdmann H.E. Cathey article Xi2012113 High-resolution biostratigraphy has been established on the basis of fossil ostracodes from cores of the Cretaceous Continental Scientific Drilling borehole-Songke 1 (south) (SK1(s)) in the Songliao Basin, northeast China. More than 80 species belonging to 13 genera have been identified and 15 ostracode assemblage zones have been recognized. On the basis of ostracode paleoecological analysis, paleoenvironments, for example lake levels and salinity, have been reconstructed. Two inferred deep-water phases occurred during the deposition of the lower Qingshankou and lower Nenjiang formations, whereas shallower water phases probably occurred during deposition of the upper Quantou and uppermost Qingshankou to Yaojia formations. The salinity of paleo-Songliao lake is interpreted as predominantly freshwater to oligohaline. Oligohaline to mesohaline water environments may have occurred during the first and middle third members of the Qingshankou formation and the lower first and lower second members of the Nenjiang formation. © 2011 Springer Science+Business Media B.V. 2012 English 00188158 10.1007/s10750-011-0765-6 Hydrobiologia 688 113-123 School of Earth Sciences and Resources, China University of Geosciences, Xueyuan Road, Haidian District, Beijing 100083, China; Daqing Oilfield, Daqing, Heilongjiang, China; Impassse des Biroulayres, 33610 Cestas, France; Centro de Geologia, Faculdade de Ciencias, Universidade de Lisboa, Campo Grande C6, 1749-016 Lisbon, Portugal 1 biostratigraphy; Cretaceous; deep water; fossil record; ostracod; paleoecology; paleoenvironment; reconstruction; salinity, China; Songliao Basin, Ostracoda https://www.scopus.com/inward/record.uri?eid=2-s2.0-84859869401&doi=10.1007%2fs10750-011-0765-6&partnerID=40&md5=d3f03c9d5d45b85e2c36e486f37dd5cb cited By 32 D. Xi S. Li X. Wan X. Jing Q. Huang J.-P. Colin Z. Wang W. Si article Cai20121196 CCSD-SK1 well was the first Cretaceous scientific drilling well in the world, locating in Songliao basin, Northeast China. It included main well (also called north well) and south well. This paper introduced the anti-collapse drilling fluid technology in main well where the desired continuous coring section was from 164.77 m to 1792.00 m. Continuous technical barriers challenged the intelligence of drilling engineers of this project. First, preserving the wellbore stability was the most critical aspect of continuous core drilling. From top to bottom, the unconsolidated sandstone in the Quaternary super stratum, the water sensitive shale in the Sifangtai group and upper stratum of the Nenjiang group, and the brittle shale of under stratum of the Nenjiang group increased the difficulty of anti-collapse drilling fluid technology. Water invasion into the shale formation often weakens the wellbore and causes problems such as wellbore collapse, shale destabilization and stuck pipe. Fluids should be designed to mitigate these shale problems. Secondly, the openhole strategy imposed the difficulty of maintaining wellbore stability in the second open process (from 245.00 m to the bottom). Finally, the total expense of the well was only one fifth ofsouth well, which was drilled by an oilfield drilling contractor. To overcome these technical challenges, not only different drilling fluid systems such as PAM drilling fluid, DFD-LG-CMC drilling fluid and DFD-NH4HPAN-SAKH drilling fluid were adopted separately, but also technology of feasible viscosity and managed pressure drilling were used. A total of 395 trips had been run in this Cretaceous scientific drilling well and no accidents even dangerous cases occurred. The experience of CCSD-SK1 (main well) explored a successful way of employing economic drilling fluid to preceding similar scientific drilling projects in similar shale formations. © (2012) Trans Tech Publications, Switzerland. 2012 English 9783037854228 16609336 10.4028/www.scientific.net/AMM.170-173.1196 Applied Mechanics and Materials 170-173 1196-1201 China University of Geoscience, Wuhan, 430074, China Drilling contractors; Managed Pressure Drilling; Northeast China; Open process; Openhole; Scientific drilling; Shale formation; Songliao basin; Stuck pipe; Technical barriers; Technical challenges; Water invasion; Water sensitive; Wellbore; Wellbore stability, Building materials; Civil engineering; Core drilling; Oil field equipment; Oil fields; Shale, Drilling fluids https://www.scopus.com/inward/record.uri?eid=2-s2.0-84861834002&doi=10.4028%2fwww.scientific.net%2fAMM.170-173.1196&partnerID=40&md5=cf8d53a3716ab86fb5356fbdf488b4d9 cited By 0 J. Cai X. Wu S. Gu article Rhodes2012 [1] The final Stage (Phase-2) of the Hawaii Scientific Drilling Project (HSDP) recovered 408 m of basaltic core (3098-3506 mbsl) attributed to Mauna Kea volcano. We determined the major and trace element composition of 40 samples from this core. Our results show that the incompatible element ratios, such as Zr/Nb, which are correlated with Pb isotopic ratios, are more variable in the lower 408 m of Mauna Kea shield lavas than in the overlying 2855 m (~450 ka). We argue that this geochemical diversity was present in the mantle source of Mauna Kea shield lavas and does not require the inter-fingering of lavas from adjacent volcanoes. Because of uncertainties in Ni partitioning between olivine and melt and the wide range of Ni contents in peridotites, we show that all Mauna Kea lavas may have been derived from a peridotite source. We also obtained major and trace element compositions for 24 whole-rock clasts and hyaloclastites and 7 glasses from HSDP Phase-1 core between 1767 and 1808 mbs. These enigmatic lavas, previously recognized by the distinctive high CaO and K2O contents of their glasses, are also relatively enriched in highly incompatible trace elements. We show that this group of lavas have affinities with post-shield lavas and argue that they are a consequence of lower degrees of melting (~a factor of two) than other Mauna Kea shield lavas, thereby providing evidence that magma supply varied significantly during the growth of the Mauna Kea shield. Copyright 2012 by the American Geophysical Union. Article 2012 English 15252027 10.1029/2011GC003812 Geochemistry, Geophysics, Geosystems 13 Blackwell Publishing Ltd 3 Hawaii [(ISL) Hawaiian Islands]; Hawaii [United States]; Hawaiian Islands; Mauna Kea; United States; Glass; Lead; Lithology; Olivine; Hawaiian volcanism; Hyaloclastites; Incompatible element; Isotopic ratios; Major and trace elements; Mantle plume; Mantle source; Mauna Kea; Ni content; Scientific drilling; geochemistry; isotopic ratio; lava; lead isotope; lithology; magma; mantle plume; mantle source; olivine; partitioning; peridotite; shield volcano; trace element; volcanism; Volcanoes https://www.scopus.com/inward/record.uri?eid=2-s2.0-84858957867&doi=10.1029%2f2011GC003812&partnerID=40&md5=fc7a3f26a9405d51a50abeb54a295b60 Cited by: 37; All Open Access, Bronze Open Access J. Michael Rhodes Shichun Huang Frederick A. Frey Malcolm Pringle Guangping Xu article Foerster201225 East African paleoenvironments are highly variable, marked by extreme fluctuations in moisture availability, which has far-reaching implications for the origin, evolution and dispersal of Homo sapiens in and beyond the region. This paper presents results from a pilot core from the Chew Bahir basin in southern Ethiopia that records the climatic history of the past 45 ka, with emphasis on the African Humid Period (AHP, ∼15-5 ka calBP). Geochemical, physical and biological indicators show that Chew Bahir responded to climatic fluctuations on millennial to centennial timescales, and to the precessional cycle, since the Last Glacial Maximum. Potassium content of the sediment appears to be a reliable proxy for aridity, showing that Chew Bahir reacted to the insolation-controlled humidity increase of the AHP with a remarkably abrupt onset and a gradual termination, framing a sharply defined arid phase (∼12.8-11.6 ka calBP) corresponding to the Younger Dryas chronozone. The Chew Bahir record correlates well with low- and high-latitude paleoclimate records, demonstrating that the site responded to regional and global climate changes. © 2012 Elsevier Ltd and INQUA. 2012 English 10406182 10.1016/j.quaint.2012.06.028 Quaternary International 274 25-37 Seminar of Geography and Education, University of Cologne, Gronewaldstraße 2, 50931 Köln, Germany; Institute of Geology and Mineralogy, Zülpicher Straße 49a-b, 50674 Köln, Germany; University of Potsdam, Institute of Earth and Environmental Science, Karl-Liebknecht-Straße 24, 14476 Potsdam-Golm, Germany; University of Addis Ababa, Department of Earth Sciences, P.O. Box 1176, Addis Ababa, Ethiopia; Institute of Geography and Earth Sciences, Aberystwyth University, Aberystwyth SY23 3DB, United Kingdom; GFZ German Centre for Geoscience Potsdam, Helmholtz Centre Potsdam, Telegrafenberg C321, 14473 Potsdam, Germany climate variation; lacustrine deposit; Last Glacial Maximum; paleoclimate; paleoenvironment; Younger Dryas, Ethiopia, Homo sapiens https://www.scopus.com/inward/record.uri?eid=2-s2.0-84866004597&doi=10.1016%2fj.quaint.2012.06.028&partnerID=40&md5=f09195cc4d210e79fe4d5f30ab59ff72 cited By 101 V. Foerster A. Junginger O. Langkamp T. Gebru A. Asrat M. Umer H.F. Lamb V. Wennrich J. Rethemeyer N. Nowaczyk M.H. Trauth F. Schaebitz article Aufgebauer2012122 This paper presents sedimentological, geochemical, and biological data from Lake Prespa (Albania/Former Yugoslav Republic of Macedonia/Greece). The 320 cm core sequence (Co1215) covers the last 17 ka calBP and reveals significant change in climate and environmental conditions on a local and regional scale. The sediment record suggests typical stadial conditions from 17.1 to 15.7 ka calBP, documented through low lake productivity, well-mixed conditions, and cold-resistant steppe catchment vegetation. Warming is indicated from 15.7 ka calBP with slightly increased in-lake productivity, gradual expansion of trees, and decreasing erosion through disappearance of local ice caps. Between 14.5 and 11.5 ka calBP relatively stable hydrological conditions are documented. The maximum in tree taxa percentages during the Bølling/Allerød interstadial (14.5-13.2 ka calBP) indicates increased temperatures and moisture availability, whereas the increase of cold-resistant open steppe vegetation taxa percentages during the Younger Dryas (13.2-11.5 ka calBP) is coupled with distinct colder and drier conditions. The Holocene sequence from 11.5 ka calBP indicates ice-free winters, stratification of the water column, a relatively high lake trophic level and dense vegetation cover over the catchment. A strong climate related impact on the limnology and physical parameters in Lake Prespa is documented around 8.2 ka through a significant decrease in productivity, enhanced mixing, strong decomposition and soil erosion, and a coeval expansion of herbs implying cool and dry climate conditions. Intensive human activity in the catchment is indicated from around 1.9 ka calBP. This multiproxy approach improves our understanding of short- and long-term climate fluctuations in this area and their impact on catchment dynamics, limnology, hydrology, and vegetation. © 2012 Elsevier Ltd and INQUA. Article 2012 English 10406182 10.1016/j.quaint.2012.02.015 Quaternary International 274 122 – 135 Albania; Balkan; Greece; Lake Mikri Prespa; Macedonia [Greece]; Turkmenistan; climate conditions; climate variation; environmental change; geochemistry; Holocene; human activity; ice cap; lacustrine deposit; limnology; paleoclimate; paleoenvironment; sediment core; sedimentology; warming; water column; Younger Dryas https://www.scopus.com/inward/record.uri?eid=2-s2.0-84865982086&doi=10.1016%2fj.quaint.2012.02.015&partnerID=40&md5=4c72551578e17b8996a7174a324d1a3d Cited by: 76 Anne Aufgebauer Konstantinos Panagiotopoulos Bernd Wagner Frank Schaebitz Finn A. Viehberg Hendrik Vogel Giovanni Zanchetta Roberto Sulpizio Melanie J. Leng Magret Damaschke article Janssen2012118 With optical microscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and synchrotron X-ray diffraction measurements, we analyzed clay microfabrics in ultracataclastic/gouge and cataclastic core samples obtained from the main bore hole of the San Andreas Fault observatory at depth (SAFOD). The analysis reveals a significant contrast between weak clay fabrics observed in the core samples with synchrotron X-ray fabric measurements and strong degree of preferred alignment for clay particles documented with the optical microscope. TEM and SEM observations also show distinct zones of locally aligned and randomly oriented clay minerals. The lack of a strong fabric may be attributed to randomly oriented matrix sheet silicates dominating the fault rocks. The presence of weak fabrics in intensely strained ultracataclasites/fault gouges is attributed to 1) newly formed clay minerals that grew in many orientations, 2) folded and kinked clay minerals, and 3) clay particles that are wrapped around grains. In addition, the locally aligned clay particles may act as barriers to fluid flow, which in turn decrease porosity, expel intergranular pore fluids, and consequently, may increase fluid pressure. © 2012 Elsevier Ltd. 2012 English 01918141 10.1016/j.jsg.2012.07.004 Journal of Structural Geology 43 118-127 GeoForschungsZentrum, Telegrafenberg, Potsdam 14473, Germany; Department of Earth and Planetary Science, University of California, Berkeley, CA 94720, United States Clay fabrics; Clay particles; Fault rock; Fluid pressures; Intergranular pores; Micro fabric; Optical microscopes; Oriented matrix; Phyllosilicate; SAFOD; San Andreas fault; SEM observation; Synchrotron x ray diffraction; Synchrotron x rays; Transmission electron microscopy tem, Clay minerals; Optical microscopy; Scanning electron microscopy; Silicates; Strike-slip faults; Tectonics; Textures; Transmission electron microscopy; X ray diffraction, Core samples, clay mineral; core (planetary); fault gouge; fluid flow; petrofabric; phyllosilicate; porosity; San Andreas Fault; scanning electron microscopy; texture; transmission electron microscopy; X-ray diffraction https://www.scopus.com/inward/record.uri?eid=2-s2.0-84866268607&doi=10.1016%2fj.jsg.2012.07.004&partnerID=40&md5=5aa52acc78f434fdfb3c17c6ead8f344 cited By 22 C. Janssen W. Kanitpanyacharoen H.-R. Wenk R. Wirth L. Morales E. Rybacki M. Kienast G. Dresen article Schleicher2012209 Segments of the modern San Andreas fault experience creep behavior, which is attributed to various factors, including (1) low values of effective normal stress, (2) elevated pore-fluid pressure, and (3) low frictional strength. The San Andreas Fault Observatory at Depth (SAFOD) drill hole in Parkfield, California, provides new insights into frictional properties by recognizing the importance of smectitic clay minerals, as demonstrated by analysis of mudrock and fault gouge samples from zones between 3186 and 3199 m and 3295 and 3313 m measured depths. X-ray diffraction (XRD) results show illite, chlorite, and mixed-layered illite-smectite and chlorite-smectite minerals in the faulted mudrock, whereas serpentine, Mg-rich smectite, and chlorite-smectite minerals are concentrated in the southwest deformation zone and the central deformation zone of the two actively creeping sections in the San Andreas fault. These rocks are abundantly coated by shiny clay mineral layers in some cases, reflecting mineral formation during creep. Secondary- and transmission-electron microscopy (SEM/TEM) and XRD studies of these slip surface coatings reveal thin films of neoformed chlorite-smectite phases, similar to previously described illite-smectite microscale precipitations. The abundance of chlorite-smectite minerals within fault rock of the SAFOD borehole significantly extends the potential role of mineralogic processes to depths up to 10 km, with cataclasis and fluid infiltration creating nucleation sites for neomineralization on displacement surfaces. We propose that localization of illitic to chloritic smectite clay minerals on slip surfaces from near the surface to the brittle-ductile transition promotes creep behavior of faults. © 2012 Geological Society of America. 2012 English 19418264 10.1130/L158.1 Lithosphere 4 Geological Society of America 209-220 Department of Earth and Environmental Sciences, University of Michigan, 1100 North University Avenue, Ann Arbor, MI 48109, United States; Institut Für Geographie Und Geologie, Ernst-Moritz-Arndt Universität, F. Ludwig-Jahn-Strasse 17A, D-17487 Greifswald, Germany 3 Creep; Friction; High resolution transmission electron microscopy; Observatories; Serpentine; Silicate minerals; Strike-slip faults; Structural geology; X ray diffraction, Brittle ductile transitions; Deformation zone; Effective normal stress; Frictional properties; Frictional strength; Mineral formation; Pore fluid pressure; San Andreas fault, Clay minerals, brittle deformation; chlorite; creep; fault displacement; fluid pressure; infiltration; mudstone; precipitation (chemistry); smectite, California; Parkfield; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-84866276240&doi=10.1130%2fL158.1&partnerID=40&md5=92733e71192f0000d8937c8f6836b11a cited By 53 A.M. Schleicher B.A. Pluijm L.N. Warr article Lachmar2012689 A geothermal test well at Mountain Home AFB in southwestern Idaho encountered artesian flow of geothermal water from a depth of 1,745 m. Samples taken from the well head after 12 hours of flow had a pH of 9.59, and an electrical conductivity of 870 μS. The high pH suggests that the water is at equilibrium with weathered basalt at the measured temperature. The water is high in sulfate relative to chloride and bicarbonate, and high in sodium relative to calcium and magnesium, but has a TDS content of only 1,120 mg/L. Pyrite is probably the source of the sulfate. Deuterium and oxygen-18 levels are -88 and -3.2 per mil, respectively, suggesting that the water is old, not meteoric, and/or has undergone significant fractionation. Calculated equilibrium temperatures vary from ∼134°C to ∼154°C. The calculated temperatures are similar to those measured in the test well. The data suggest a potential electric-grade resource. Further work is in progress. 2012 English 9781622764341 01935933 Transactions - Geothermal Resources Council 36 1 689-692 Department of Geology, Utah State University, Logan, UT, United States; Idaho National Laboratory, Idaho Falls, ID, United States; DOSECC, Inc., Salt Lake City, UT, United States Calcium and magnesiums; Electrical conductivity; Equilibrium temperatures; Geothermal water; Hot spot; Measured temperatures; Mountain Home; Snake river plains, Basalt; Chemistry; Chlorine compounds; Electric conductivity; Geothermal fields; Landforms; Sodium bicarbonate; Sodium sulfate, Geothermal wells https://www.scopus.com/inward/record.uri?eid=2-s2.0-84876257544&partnerID=40&md5=6362105e04c4dfb1138a410ececf94f6 cited By 4 T.E. Lachmar T.G. Freeman T.R. Wood J.W. Shervais D.L. Nielson article meiyan2012characteristics 2012 石油实验地质 34 石油实验地质 585-593 6 Fu Meiyan Zhang Shaonan Ding Xiaoqi Liao Qiming Xiong Di Zhu Zhiliang article Li201288 To further investigate the significance of carbon isotopes of lake carbonates in arid areas, we examined the carbon isotopic composition of ostracods, bulk carbonate, fine-grained carbonates, and associated water DIC (dissolved inorganic carbon) from Lake Qinghai and several small lakes and ponds surrounding Lake Qinghai. We obtained three major results. 1) The carbon isotopic compositions of ostracods, bulk carbonate, and fine-grained carbonates in the lakes and ponds are clearly correlated with water δ 13C DIC values, which vary with water salinity in the Lake Qinghai area. 2) The variation in the δ 13C DIC values of lake water is mainly controlled by CO 2 exchanges between the atmosphere and lake waters in the Lake Qinghai area. 3) Ostracods, bulk carbonate and fine-grained carbonates show consistent trends of isotopic composition in the study area, and the differences in carbon isotopic composition between authigenic carbonates and ostracods may be explained by the differences in carbon isotopic composition between the DIC of surface water and that of the water near to the sediment-water interface as well as the 'vital offsets' of ostracods.Our results suggest that variations in the δ 13C values of carbonates in Lake Qinghai and other lakes in this arid, high-altitude area are primarily controlled by the carbon-isotope ratios of the lake water DIC, which in turn are related to water salinity. Therefore, changes in carbonate δ 13C values may be used to indirectly indicate changes in water salinity in the Lake Qinghai area. © 2012 Elsevier B.V.. Article 2012 English 00092541 10.1016/j.chemgeo.2012.01.010 Chemical Geology 300-301 88 – 96 China; Qinghai; Qinghai Lake; Ostracoda; Animals; Anoxic sediments; Arid regions; Carbon; Carbon dioxide; Carbonates; Carbonation; Isotopes; Sedimentology; Arid area; Authigenic carbonates; Carbon isotopes; Carbon isotopic composition; Dissolved inorganic carbon; High altitude; Isotopic composition; Lake Qinghai; Lake waters; Ostracods; Qinghai Tibet plateau; Sediment water interface; Study areas; Water salinity; arid region; carbon isotope; carbonate sediment; dissolved inorganic carbon; isotopic composition; isotopic ratio; lacustrine deposit; ostracod; Lakes https://www.scopus.com/inward/record.uri?eid=2-s2.0-84862812819&doi=10.1016%2fj.chemgeo.2012.01.010&partnerID=40&md5=20aae3a39259236fa358383bfecff259 Cited by: 60 Xiangzhong Li Weiguo Liu Liming Xu article Wang201236 Lake sediments generally contain a mixture of terrestrial and aquatic source inputs, and determining the major inputs is important for understanding geological records in paleoenvironment and paleoclimate research. In this study we describe the distribution of n-alkanes and n-fatty acids (FAs) in representative modern plants from around Lake Qinghai. We found a significant difference in the average length of n-FA carbon chains (ACL Fa 16-32) in terrestrial (23.3) and aquatic plants (18.6). The results reveal that ACL Fa 16-32 may essentially serve as a proxy for evaluating the major source inputs to lake sediments. Assessment of surface sediments from the lake showed that the FAs originated from a mixture of inputs, with the aquatic source input predominant at most sites.Additionally, the δD values of sediment mid-chain n-acids (C 22) showed a relationship with the ACL Fa 16-32 proxy: an increased Fa ACL corresponded to more negative hydrogen isotope ratio values. We suggest that different sources should be considered and ACL Fa 16-32 could be a potential calibration proxy before using δD values to extract reliable isotopic information from lake water. More attention should be paid to source inputs and their relationship to other geochemical proxies in future studies of lake sediments. © 2012 Elsevier Ltd. Article 2012 English 01466380 10.1016/j.orggeochem.2012.06.015 Organic Geochemistry 50 36 – 43 China; Qinghai; Qinghai Lake; Carbon; Hydrogen; Isotopes; Paraffins; Sedimentology; Sediments; Aquatic plants; Average length; Carbon chains; Carbon-chain length; Geochemical proxies; Hydrogen isotope; Isotopic information; Lake Qinghai; Lake sediments; Lake waters; n-Alkanes; Paleo-environment; Paleoclimate research; Surface sediments; alkane; carbon; fatty acid; geological record; hydrogen isotope; lacustrine deposit; lake water; paleoclimate; paleoenvironment; sediment chemistry; Lakes https://www.scopus.com/inward/record.uri?eid=2-s2.0-84864148208&doi=10.1016%2fj.orggeochem.2012.06.015&partnerID=40&md5=7f5f699a4c47fc2685b216f60c478295 Cited by: 54 Zheng Wang Weiguo Liu article gang2012boundary 2012 Journal of Stratigraphy 36 569-578 3 Han Gang Zhang Wenjing Huang Qinghua others article Chapligin2012185 Mineral particles and other contaminants cause a serious and undesirable shift in δ 18O values of biogenic silica and should be removed prior to isotope analysis. This problem is particularly significant in the fraction containing clay particles and therefore the fraction &lt;10μm is generally avoided. Here, we present an updated preparation protocol for the &lt;10μm fraction based on known methods, developed using test material from short cores of Lake El'gygytgyn, NE Russia. New contamination assessment and correction techniques are discussed. Best results (low initial weight/high precision and throughput rate) for the &lt;10μm fraction were achieved using geochemical mass-balancing and determining the "percentage of contamination" by analysing the sample's and end-member's Al 2O 3 with improved Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES) and Energy-Dispersive X-ray Spectroscopy (EDS) protocols or by determining the factor for calculating the percentage of contamination from the Al 2O 3 percentage of clay assemblages. Despite using small initial weights for ICP-OES (10mg) and EDS analysis (&lt;0.5mg) a sufficiently high precision (for low Al 2O 3 percentages between 0.1 and 1.5%) could be achieved.For the &gt;10μm fraction, point-counting under the light microscope was the preferred option. The different size-fractions from Lake El'gygytgyn samples show a distinct and significantly different species composition (average counts: &lt;10μm: &gt;90% Cyclotella ocellata complex; &gt;10μm: &gt;60% Pliocaenicus seczkinae). Differences in the oxygen isotope composition of these different size fractions could be explained by a species-effect on the δ 18O values. However, this species-effect disappeared after the correction (avg δ 18O &lt;10μm: 19.8±0.6‰; &gt;10μm: 19.8±0.4‰). By comparing these δ 18O values with additional recent water samples, an average 1000 ln α of 39.6‰ for Lake El'gygytgyn sub-recent diatoms was calculated. This "tool-kit" provides support for the presented improved contamination assessment and corrections and allows utilising smaller initial weight (app. 10mg) and small fractions (&lt;10μm) for gaining corrected, higher resolution δ 18O records. © 2012 Elsevier B.V.. 2012 English 00092541 10.1016/j.chemgeo.2012.01.004 Chemical Geology 300-301 185-199 Alfred Wegener Institute for Polar and Marine Research, Research Unit Potsdam, Telegrafenberg A43, D-14473 Potsdam, Germany; Bowling Green State University, Department of Geology, Bowling Green, OH 43403, United States; German Research Center for Geosciences (GFZ), Helmholtz Centre Postdam Telegrafenberg, D-14473 Potsdam, Germany Diatoms; El'gygytgyn; ICP-OES; Species-effect; XRF, Aluminum; Emission spectroscopy; Energy dispersive spectroscopy; Inductively coupled plasma; Isotopes; Lakes; Oxygen; Phytoplankton; Rating; Silica, Contamination, assessment method; biogenic material; biomonitoring; error correction; inductively coupled plasma method; isotopic composition; lake pollution; mass balance; oxygen isotope; pollutant transport; purification; silica; X-ray spectroscopy, Chukchi; Elgygytgyn Lake; Russian Federation, Bacillariophyta; Cyclotella ocellata; Pliocaenicus https://www.scopus.com/inward/record.uri?eid=2-s2.0-84857319780&doi=10.1016%2fj.chemgeo.2012.01.004&partnerID=40&md5=e36f25a9ce51543e98df29552d5d1116 cited By 32 B. Chapligin H. Meyer A. Bryan J. SNYDER H. Kemnitz article Huang201283 We present a conditional simulation algorithm to parameterize three-dimensional heterogeneities and construct heterogeneous petrophysical reservoir models. The models match the data at borehole locations, simulate heterogeneities at the same resolution as borehole logging data elsewhere in the model space, and simultaneously honor the correlations among multiple rock properties. The model provides a heterogeneous environment in which a variety of geophysical experiments can be simulated. This includes the estimation of petrophysical properties and the study of geophysical response to the heterogeneities. As an example, we model the elastic properties of a gas hydrate accumulation located at Mallik, Northwest Territories, Canada. The modeled properties include compressional and shear-wave velocities that primarily depend on the saturation of hydrate in the pore space of the subsurface lithologies. We introduce the conditional heterogeneous petrophysical models into a finite difference modeling program to study seismic scattering and attenuation due to multi-scale heterogeneity. Similarities between resonance scattering analysis of synthetic and field Vertical Seismic Profile data reveal heterogeneity with a horizontal-scale of approximately 50. m in the shallow part of the gas hydrate interval. A cross-borehole numerical experiment demonstrates that apparent seismic energy loss can occur in a pure elastic medium without any intrinsic attenuation of hydrate-bearing sediments. This apparent attenuation is largely attributed to attenuative leaky mode propagation of seismic waves through large-scale gas hydrate occurrence as well as scattering from patchy distribution of gas hydrate. © 2011 Elsevier B.V.. 2012 English 09269851 10.1016/j.jappgeo.2011.12.002 Journal of Applied Geophysics 77 83-96 University of Toronto, 60 St. George Street, Toronto ON M5S 1A7, Canada; Geological Survey of Canada, 615 Booth Street, Ottawa ON K1A 0E9, Canada Borehole logging; Compressional; Conditional simulations; Distribution of gas; Elastic medium; Elastic properties; Finite-difference modeling; Gas hydrate reservoir; Heterogeneous environments; Heterogeneous rocks; Hydrate accumulations; Leaky modes; Model spaces; Multiscales; Numerical experiments; Petrophysical; Petrophysical models; Petrophysical properties; Pore space; Reservoir models; Resonance scattering; Rock properties; Seismic energy; Shear-wave velocity; Subsurface lithology; Vertical seismic profiles, Anoxic sediments; Energy dissipation; Experiments; Gases; Hydration; Petroleum reservoirs; Scattering; Seismic waves; Seismology; Shear flow; Three dimensional, Gas hydrates, algorithm; borehole logging; computer simulation; elastic property; gas hydrate; heterogeneous medium; rock property; S-wave; saturation; seismic attenuation; seismic data; three-dimensional modeling; wave propagation; wave scattering; wave velocity, Canada; Northwest Territories https://www.scopus.com/inward/record.uri?eid=2-s2.0-84855252442&doi=10.1016%2fj.jappgeo.2011.12.002&partnerID=40&md5=fd403a1857c8b0848e3227e48b5048af cited By 6 J.W. Huang G. Bellefleur B. Milkereit article Belza2012400 To better constrain the emplacement mechanism of the so-called "mega-block zone," a structurally complex unit of target rocks within the Chicxulub impact structure, the stratigraphic coherence of this zone is tested using its strontium isotopic composition. Forty-eight samples across the 616m sequence of deformed Cretaceous rocks in the lower part of the Yaxcopoil-1 core, drilled by ICDP in 2002, were analyzed for their 87Sr/ 86Sr isotope ratio. The oceanic anoxic event 2 (OAE2 event), located near the base of the core forms the only stratigraphic anchor point. From this point upward to approximately 1050m depth, the 87Sr/ 86Sr trend shows small oscillations, between approximately 0.7074 and 0.7073, characteristic of Cenomanian to Santonian values. This is followed by an increase to approximately 0.7075, similar to the one reported in the seawater strontium curve during the Campanian. Scattered Sr isotope ratios are attributed to local diagenetic effects, such as those expected from the possible presence of hot, impact-induced dikes and hydrothermal fluid flow, originating from the thick central melt sheet. The absence of Upper Maastrichtian Sr isotope values may result from the removal of upper target lithologies during the impact cratering process. Based on these results, the displaced Cretaceous sequence in Yax-1 appears to have preserved its stratigraphic coherence. During the modification stage, it probably moved as a whole into the annular basin during collapse of the crater wall, thereby breaking up into discrete units along previously weakened detachment zones. This model is consistent with the emplacement mechanism postulated by Kenkmann et al. (2004). © 2012 The Meteoritical Society. 2012 10.1111/j.1945-5100.2012.01345.x Meteoritics and Planetary Science 47 400-413 Department of Geology, Vrije Universiteit Brussels, Pleinlaan 2, BE1050 Brussels, Belgium; Department of Analytical Chemistry, Universiteit Gent, Krijgslaan 281-S12, BE9000 Ghent, Belgium 3 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84859203668&doi=10.1111%2fj.1945-5100.2012.01345.x&partnerID=40&md5=232f01620d5a690d83ee42c43fcc5015 cited By 10 J. Belza S. Goderis E. Keppens F. Vanhaecke P. Claeys article Moore201251 Magnesium-rich clayey gouge similar to that comprising the two actively creeping strands of the San Andreas Fault in drill core from the San Andreas Fault Observatory at Depth (SAFOD) has been identified in a nearby outcrop of serpentinite within the fault zone at Nelson Creek. Each occurrence of the gouge consists of porphyroclasts of serpentinite and sedimentary rocks dispersed in a fine-grained, foliated matrix of Mg-rich smectitic clays. The clay minerals in all three gouges are interpreted to be the product of fluid-assisted, shear-enhanced reactions between quartzofeldspathic wall rocks and serpentinite that was tectonically entrained in the fault from a source in the Coast Range Ophiolite. We infer that the gouge at Nelson Creek connects to one or both of the gouge zones in the SAFOD core, and that similar gouge may occur at depths in between. The special significance of the outcrop is that it preserves the early stages of mineral reactions that are greatly advanced at depth, and it confirms the involvement of serpentinite and the Mg-rich phyllosilicate minerals that replace it in promoting creep along the central San Andreas Fault. © 2011. 2012 English 01918141 10.1016/j.jsg.2011.11.014 Journal of Structural Geology 38 51-60 U.S. Geological Survey, Earthquake Science Center, 345 Middlefield Road, Mail Stop 977, Menlo Park, CA 94025, United States Coast range ophiolites; Metasomatic reactions; SAFOD; San Andreas fault; Serpentinite; Smectite clays, Buildings; Clay minerals; Core drilling; Magnesium; Observatories, Strike-slip faults, correlation; creep; fault gouge; fault zone; metasomatism; ophiolite; outcrop; San Andreas Fault; sedimentary rock; serpentinite; smectite; tectonic setting https://www.scopus.com/inward/record.uri?eid=2-s2.0-84859931557&doi=10.1016%2fj.jsg.2011.11.014&partnerID=40&md5=3a8b494b4880c9fefebb0022c7983086 cited By 44 D.E. Moore M.J. Rymer article Williams20121219 This article examines a report in the 27th chapter of the Gospel of Matthew in the New Testament that an earthquake was felt in Jerusalem on the day of the crucifixion of Jesus of Nazareth. We have tabulated a varved chronology from a core from Ein Gedi on the western shore of the Dead Sea between deformed sediments due to a widespread earthquake in 31 BC and deformed sediments due to an early first-century earthquake. The early first-century seismic event has been tentatively assigned a date of 31 AD with an accuracy of 5 years. Plausible candidates include the earthquake reported in the Gospel of Matthew, an earthquake that occurred sometime before or after the crucifixion and was in effect borrowed by the author of the Gospel of Matthew, and a local earthquake between 26 and 36 AD that was sufficiently energetic to deform the sediments at Ein Gedi but not energetic enough to produce a still extant and extra-biblical historical record. If the last possibility is true, this would mean that the report of an earthquake in the Gospel of Matthew is a type of allegory. © 2012 Copyright Taylor and Francis Group, LLC. 2012 English 00206814 10.1080/00206814.2011.639996 International Geology Review 54 1219-1228 Supersonic Geophysical, LLC, Los Angeles, CA 90042, United States; GFZ - German Research Centre for Geosciences, Section 5.2 Climate Dynamics and Landscape Evolution, 14473, Potsdam, Germany 10 chronology; earthquake; Holocene; seismicity; varve, Dead Sea https://www.scopus.com/inward/record.uri?eid=2-s2.0-84861801572&doi=10.1080%2f00206814.2011.639996&partnerID=40&md5=0d8bc24d76c84ee41f2a05d8dbc0d097 cited By 5 J.B. Williams M.J. Schwab A. Brauer article Dzirasah201295 Lake Bosumtwi in Ghana, has been the focus of international paleoclimate research during which continuous sediment cores were recovered for mutliproxy paleoclimate studies. Seventy-six (76) samples of the top 2-8 cm of the sediments were collected at different locations throughout the lake with Ekman dredge to determine indications of depositional environment and paleoclimate. The percentage (%) water and percentage (%) organic matter contents, and the magnetic mineralogy of the sediment samples were determined. The magnetic measurements carried out include isothermal remanent magnetization (IRM), anhysteric remanent magnetisation (ARM) and magnetic susceptibility. The results showed that the percentage (%) water and percentage (%) organic matter contents increased with increasing water depth. The magnetic susceptibilities of the samples increased with increasing water depth, whereas the percentage (%) frequency dependence of susceptibility has a gentle increase with water depth. Most parameters measured show an abrupt change at about 18 m water depth. Values for S-ratio averaged 0.93, indicating the presence of low coercivity magnetic minerals such as maghemite and magnetite. These low coercivity minerals in the surface sediments were deposited in the presently warm and wet interglacial climate with reduced Sahara/Sahel dust influx to Ghana. © EuroJournals Publishing, Inc. 2012. Article 2012 English 1450216X European Journal of Scientific Research 82 EuroJournals, Inc. 95 – 114 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84864580139&partnerID=40&md5=ea2b94926a4b9f995fdd6aaff8e97ac7 Cited by: 1 W. Dzirasah S.K. Danuor A. Menyeh J.E. Peck article Huguet20123628 Lake Van in Turkey is the world's largest soda lake (607 km3). The lake's catchment area is estimated to be ~12,500 km2, and the terrestrial input is carried through eolian, riverine, snowmelt and anthropogenic paths. Extent and seasonality of the terrestrial inputs to the lake have not been studied, but it is essential to evaluate its environmental status and to assess the use of environmental proxies to estimate the lake's response to climate changes. This study aims to measure seasonal changes in terrestrial input of natural and anthropogenic origin as recorded by the fluxes of pollen and biomarkers of soil bacteria and vascular or higher plants, as well as petrogenic biomarkers in monthly resolved sediment traps from August 2006 to July 2007. Fluxes of pollen, soil and higher plant biomarkers seem to be related to precipitation and snowmelt in autumn and spring. In addition, dust storms, which are common during the summer months, may have resulted in long-distance transport. Anthropogenic biomarker fluxes indicate year-round petrogenic contamination although some mature biomarker fluxes are higher in summer and in late winter-spring. The relative changes between petrogenic markers indicate variations in the pollutant sources. © 2012 Springer-Verlag. 2012 English 09441344 10.1007/s11356-012-0948-3 Environmental Science and Pollution Research 19 3628-3635 Institut de Ciència i Tecnologia Ambientals (ICTA), Universitat Autònoma de Barcelona (UAB), Edifici CN, torre C5, 4a planta, Campus UAB, 08193 Bellaterra, Spain; Steinmann Institute of Geology, Mineralogy and Palaeontology, University of Bonn, Bonn, Germany; Department of Surface Water Research and Management, Eawag, Swiss Federal Institute of Aquatic Science and Technology, Uberlandstrasse 133, 8600 Dubendorf, Switzerland 8 biological marker, alkane; anthropogenic source; bacterium; biomarker; catchment; climate change; dust storm; eolian deposit; freshwater sediment; lake pollution; pollen; saline lake; seasonality; sediment trap; snowmelt; soil microorganism; terrestrial deposit, article; chemistry; environmental monitoring; lake; microbiology; pollen; season; Turkey (republic); water pollutant, Biological Markers; Environmental Monitoring; Lakes; Pollen; Seasons; Soil Microbiology; Turkey; Water Pollutants, Chemical, Lake Van; Turkey, Embryophyta; Tracheophyta https://www.scopus.com/inward/record.uri?eid=2-s2.0-84865534666&doi=10.1007%2fs11356-012-0948-3&partnerID=40&md5=6ae90e779c93d816d2c6ab4f246aa602 cited By 8 C. Huguet S. Fietz N. Moraleda T. Litt G. Heumann M. Stockhecke F.S. Anselmetti M. Sturm article Robin-Popieul20122191 The oldest well-preserved komatiites, and the type examples, are found in the Barberton Greenstone Belt in South Africa (3·5-3·3 Ga). All three komatiite types are present, commonly within the same stratigraphic unit. Al-depleted komatiites have low Al/Ti, relatively high concentrations of incompatible elements and depleted heavy rare earth elements (HREE); Al-undepleted komatiites have chondritic Al/Ti and flat HREE patterns; and Al-enriched komatiites have high Al/Ti, low concentrations of incompatible elements, enriched HREE and extremely depleted light rare earth elements. Based on a comprehensive petrological and geochemical study, we propose a new melting model for the formation of these magmas. The basis of the model is the observation, from published experimental studies, that at great depths (~13 GPa) the density of komatiitic liquid is similar to that of solid peridotite. At such depths, melting in a rising mantle plume produces near-neutrally buoyant komatiite melt that does not escape from the residual peridotite. As the source ascends to shallower levels, however, the pressure decreases and the density difference increases, eventually making melt escape possible. Al-depleted komatiites form first at about 13 GPa by equilibrium melting under conditions in which a large proportion of melt (30-40%) was retained in the source and the residue contained a high proportion of garnet (15%). Al-undepleted and Al-enriched komatiites form by fractional melting at intermediate to shallow depths after the escape of a large proportion of melt and after exhaustion of residual garnet. This model reproduces the chemical characteristics of all komatiite types in the Barberton belt and can probably be applied to komatiites in other parts of the world. © The Author 2012. Published by Oxford University Press. All rights reserved. Article 2012 English 14602415 10.1093/petrology/egs042 Journal of Petrology 53 2191 – 2229 11 Barberton Greenstone Belt; Archean; concentration (composition); geochemistry; komatiite; magma; mantle plume; modeling; peridotite; petrogenesis; petrology; rare earth element https://www.scopus.com/inward/record.uri?eid=2-s2.0-84867776716&doi=10.1093%2fpetrology%2fegs042&partnerID=40&md5=81e2e6b6920aab204c65b9decc0d9c7a Cited by: 94; All Open Access, Bronze Open Access Christophe C.M. Robin-Popieul Nicholas T. Arndt Catherine Chauvel Gary R. Byerly Alexander V. Sobolev Allan Wilson article Hadizadeh2012246 The San Andreas Fault zone in central California accommodates tectonic strain by stable slip and microseismic activity. We study microstructural controls of strength and deformation in the fault using core samples provided by the San Andreas Fault Observatory at Depth (SAFOD) including gouge corresponding to presently active shearing intervals in the main borehole. The methods of study include high-resolution optical and electron microscopy, X-ray fluorescence mapping, X-ray powder diffraction, energy dispersive X-ray spectroscopy, white light interferometry, and image processing.The fault zone at the SAFOD site consists of a strongly deformed and foliated core zone that includes 2-3 m thick active shear zones, surrounded by less deformed rocks. Results suggest deformation and foliation of the core zone outside the active shear zones by alternating cataclasis and pressure solution mechanisms. The active shear zones, considered zones of large-scale shear localization, appear to be associated with an abundance of weak phases including smectite clays, serpentinite alteration products, and amorphous material. We suggest that deformation along the active shear zones is by a granular-type flow mechanism that involves frictional sliding of microlithons along phyllosilicate-rich Riedel shear surfaces as well as stress-driven diffusive mass transfer. The microstructural data may be interpreted to suggest that deformation in the active shear zones is strongly displacement-weakening. The fault creeps because the velocity strengthening weak gouge in the active shear zones is being sheared without strong restrengthening mechanisms such as cementation or fracture sealing. Possible mechanisms for the observed microseismicity in the creeping segment of the SAF include local high fluid pressure build-ups, hard asperity development by fracture-and-seal cycles, and stress build-up due to slip zone undulations. © 2012 Elsevier Ltd. 2012 English 01918141 10.1016/j.jsg.2012.04.011 Journal of Structural Geology 42 246-260 Department of Geography and Geosciences, University of Louisville, 212 Lutz Hall, Louisville KY 40292, United States; University of Padova, Padova, Italy; University Joseph Fourier and CNRS, ISTerre, BP 53, 3804 Grenoble, France; University of Oslo, PGP, Oslo, Norway; Istituto Nazionale di Geofisica e Vulcanologia, Rome, Italy; Georgia State University, Geosciences, Atlanta, GA, United States Cataclasis; Foliated gouge; Pressure solution; SAFOD; San Andreas fault; Shear localizations, Clay minerals; Creep; Electron microscopy; Fracture; Image processing; Strike-slip faults; Structural geology; X ray powder diffraction; X ray spectroscopy, Shear flow, asperity; creep; deformation mechanism; fault gouge; fault zone; foliation; microstructure; San Andreas Fault; seismicity; shear zone; slip, California; San Andreas; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-84865338082&doi=10.1016%2fj.jsg.2012.04.011&partnerID=40&md5=102bc01d3ed4e8190f2fa67056598cc8 cited By 46 J. Hadizadeh S. Mittempergher J.-P. Gratier F. Renard G. Di Toro J. Richard H.A. Babaie article cp-8-1621-2012 In 2003 sediment core Lz1024 was drilled at Lake El'gygytgyn, far east Russian Arctic, in an area of the Northern Hemisphere which has not been glaciated for the last 3.6 Ma. Biogenic silica was used for analysing the oxygen isotope composition (δ18Odiatom) in the upper 13 m long section dating back about 250 ka with samples dominated by one taxa in the &lt;10 μm fraction (Cyclotella ocellata). Downcore variations in δ18O values show that glacial-interglacial cycles are present throughout the core and δ18Odiatom-values are mainly controlled by δ18Oprecipitation. Changes reflect the Holocene Thermal Maximum, the Last Glacial Maximum (LGM) and the interglacial periods corresponding to MIS 5.5 and MIS 7 with a peak-to-peak amplitude between LGM and MIS 5.5 of Δ18O = 5.3‰. This corresponds to a mean annual air temperature difference of about 9 °C. Our record is the first continuous δ18Odiatom record from an Arctic lake sediment core directly responding to precipitation and dating back more than 250 ka and correlates well with the stacked marine δ18O LR04 (r = 0.58) and δD EPICA Dome-C record (r = 0.69). With δ18O results indicating strong links to both marine and ice-core records, records from Lake El'gygytgyn can be used to further investigate the sensitivity of the Arctic climate to both past and future global climatic changes. © Author(s) 2012. 2012 English 18149324 10.5194/cp-8-1621-2012 Climate of the Past 8 1621-1636 Alfred Wegener Institute for Polar and Marine Research, Research Unit Potsdam, Telegrafenberg A43, 14473 Potsdam, Germany; School of Geography, University of Nottingham, University Park, Nottingham, NG7 2RD, United Kingdom; Department of Ecology and Environmental Science, Umeå University, 901 87 Umeå, Sweden 5 air temperature; arctic environment; diatom; glacial-interglacial cycle; ice core; isotopic composition; lacustrine deposit; Last Glacial Maximum; marine isotope stage; oxygen isotope; sediment core; silica, Antarctica; Arctic; Chukchi; Dome Concordia; East Antarctica; Elgygytgyn Lake; Russian Federation https://cp.copernicus.org/articles/8/1621/2012/ cited By 29 B. Chapligin H. Meyer G. E. A. Swann C. Meyer-Jacob H.-W. Hubberten article Litt201218 International Continental Scientific Drilling Program (ICDP) drilled a complete succession of the lacustrine sediment sequence deposited during the last -500,000 years in Lake Van, Eastern Anatolia (Turkey). Based on a detailed seismic site survey, two sites at a water depth of up to 360 m were drilled in summer 2010, and cores were retrieved from sub-lake-floor depths of 140 m (Northern Basin) and 220 m (Ahlat Ridge). To obtain a complete sedimentary section, the two sites were multiple-cored in order to investigate the paleoclimate history of a sensitive semi-arid region between the Black, Caspian, and Mediterranean seas. Further scientific goals of the PALEOVAN project are the reconstruction of earthquake activity, as well as the temporal, spatial, and compositional evolution of volcanism as reflected in the deposition of tephra layers. The sediments host organic matter from different sources and hence composition, which will be unravelled using biomarkers. Pathways for migration of continental and mantle-derived noble gases will be analyzed in pore waters. Preliminary 40Ar/39Ar single crystal dating of tephra layers and pollen analyses suggest that the Ahlat Ridge record encompasses more than half a million years of paleoclimate and volcanic/geodynamic history, providing the longest continental record in the entire Near East to date. 2012 English 18168957 10.5194/sd-14-18-2012 Scientific Drilling Copernicus GmbH 18-29 Steinmann Institute of Geology, Mineralogy and Paleontology, Bonn University, Bonn, Germany; GEOMAR, Helmholtz Centre for Ocean Research Kiel, Wischhofstr. 1-3, 24148 Kiel, Germany; Eawag, Swiss Federal Institute of Aquatic Science and Technology, Dübendorf and Kastanienbaum, Switzerland; Yüzüncü Yil Üniversitesi, Mühendislik - Mimarlik Fakultesi Jeoloji Mühendisliǧi Bölümü, Van, Turkey; Department of Geological Engineering and Eastern Mediterranean, Centre for Oceanography and Limnology, Istanbul Technical University, Istanbul, Turkey; Leibniz-Institute for Applied Geophysics (LIAG), Hannover, Germany; Potsdam University, Institute for Earth and Environmental Sciences, Geomicrobiology Group, Potsdam, Germany; Istituto di Scienze Marine, ISMAR, CNR, Bologna, Italy 14 Inert gases; Lakes; Sediments; Single crystals, Compositional evolution; Continental scientific drillings; Drilling projects; Earthquake activity; Environmental history; Lacustrine sediments; Mediterranean sea; Semi-arid region, Infill drilling https://www.scopus.com/inward/record.uri?eid=2-s2.0-84867822516&doi=10.5194%2fsd-14-18-2012&partnerID=40&md5=e8787e1c49e6431fd49a21f3fb0418e7 cited By 37 T. Litt F.S. Anselmetti H. Baumgarten J. Beer N. Cagatay D. Cukur E. Damci C. Glombitza G. Haug G. Heumann J. Kallmeyer R. Kipfer S. Krastel O. Kwiecien A. Feray Meydan S. Orcen N. Pickarski M.-E. Randlett H.-U. Schmincke C.J. Schubert M. Sturm M. Sumita M. Stockhecke Y. Tomonaga L. Vigliotti T. Wonik article Jourdan2012 The Hawaii Scientific Drilling Project recovered core from a 3.5 km deep hole from the flank of Mauna Kea volcano, providing a long, essentially continuous record of the volcano's physical and petrologic development that has been used to infer the chemical and physical characteristics of the Hawaiian mantle plume. Determining a precise accumulation rate via 40Ar/ 39Ar dating of the shield-stage tholeiites, which constitute 95-98% of the volcano's volume is challenging. We applied 40Ar/ 39Ar dating using laser- and furnace-heating in two laboratories (Berkeley and Curtin) to samples of two lava flows from deep in the core (∼3.3 km). All determinations yield concordant isochron ages, ranging from 612 ± 159 to 871 ± 302 ka (2σ; with P ≥ 0.90). The combined data yield an age of 681 ± 120 ka (P = 0.77) for pillow lavas near the bottom of the core. This new age, when regressed with 40Ar/39Ar isochron ages previously obtained for tholeiites higher in the core, defines a constant accumulation rate of 8.4 ± 2.6 m/ka that can be used to interpolate the ages of the tholeiites in the HSDP core with a mean uncertainty of about ±83 ka. For example at ∼3300 mbsl, the age of 664 ± 83 ka estimated from the regression diverges at the 95% confidence level from the age of 550 ka obtained from the numerical model of DePaolo and Stolper (1996). The new data have implications for the timescale of the growth of Hawaiian volcanoes, the paleomagnetic record in the core, and the dynamics of the Hawaiian mantle plume. Copyright 2012 by the American Geophysical Union. Article 2012 English 15252027 10.1029/2011GC004017 Geochemistry, Geophysics, Geosystems 13 Blackwell Publishing Ltd 5 Hawaii [(ISL) Hawaiian Islands]; Hawaii [United States]; Hawaiian Islands; Mauna Kea; United States; Infill drilling; Thermal plumes; Accumulation rates; Chemical and physical characteristics; Hawaii; Mauna keas; Ocean island basalts; Paleomagnetic record; Scientific drilling; volcanology; argon-argon dating; mantle plume; ocean island basalt; paleomagnetism; petrology; regression analysis; tholeiite; timescale; uncertainty analysis; volcanology; Volcanoes https://www.scopus.com/inward/record.uri?eid=2-s2.0-84861319786&doi=10.1029%2f2011GC004017&partnerID=40&md5=dcc57cc333cb917a5fa05a3de2738f27 Cited by: 18; All Open Access, Bronze Open Access, Green Open Access Fred Jourdan Warren D. Sharp Paul R. Renne article Melles2012315 The reliability of Arctic climate predictions is currently hampered by insufficient knowledge of natural climate variability in the past. A sediment core from Lake El'gygytgyn in northeastern (NE) Russia provides a continuous, high-resolution record from the Arctic, spanning the past 2.8 million years. This core reveals numerous "super interglacials" during the Quaternary; for marine benthic isotope stages (MIS) 11c and 31, maximum summer temperatures and annual precipitation values are ∼4° to 5°C and ∼300 millimeters higher than those of MIS 1 and 5e. Climate simulations show that these extreme warm conditions are difficult to explain with greenhouse gas and astronomical forcing alone, implying the importance of amplifying feedbacks and far field influences. The timing of Arctic warming relative to West Antarctic Ice Sheet retreats implies strong interhemispheric climate connectivity. 2012 English 00368075 10.1126/science.1222135 Science 337 American Association for the Advancement of Science 315-320 Institute of Geology and Mineralogy, University of Cologne, Zuelpicher Strasse 49a, D-50674 Cologne, Germany; Department of Geosciences, University of Massachusetts, 611 North Pleasant Street, Amherst, MA 01003, United States; Far East Branch Russian Academy of Sciences, North-East Interdisciplinary Scientific Research Institute, 16 Portovaya Street, 685000 Magadan, Russian Federation; Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences, Telegrafenberg C321, D-14473 Potsdam, Germany; Department of Earth and Space Sciences, University of Washington, Box 351310, Seattle, WA 98195-1310, United States; Climate Impacts Research Centre, Umeå University, SE-981 07 Abisko, Sweden; Institute of Geological Sciences, Free University Berlin, Haus D, Malteserstrasse 74-100, D-12249 Berlin, Germany; Department of Physical and Earth Sciences, Worcester State University, Worcester, MA 01602, United States; Department of Geology, Lund University, Sölvegatan 12, S-223 62 Lund, Sweden 6092 arctic environment; climate modeling; climate prediction; climate variation; greenhouse gas; ice sheet; interglacial; marine isotope stage; precipitation (climatology); sediment core, arctic climate; article; benthos; climate change; greenhouse effect; greenhouse gas; interglacial; lake; priority journal; Quaternary (period); Russian Federation; seasonal variation; summer, Antarctica; Arctic; Chukchi; Elgygytgyn Lake; Russian Federation; West Antarctic Ice Sheet; West Antarctica https://www.scopus.com/inward/record.uri?eid=2-s2.0-84863991981&doi=10.1126%2fscience.1222135&partnerID=40&md5=daded2d6271d52289f62ef3609e8f75d cited By 339 M. Melles J. Brigham-Grette P.S. Minyuk N.R. Nowaczyk V. Wennrich R.M. DeConto P.M. Anderson A.A. Andreev A. Coletti T.L. Cook E. Haltia-Hovi M. Kukkonen A.V. Lozhkin P. Rosen P. Tarasov H. Vogel B. Wagner incollection melezhik20121 2012 Reading the Archive of Earth’s Oxygenation: Volume 1: The Palaeoproterozoic of Fennoscandia as Context for the Fennoscandian Arctic Russia-Drilling Early Earth Project Springer 25--30 Victor A Melezhik incollection melezhik20121 2012 Reading the Archive of Earth’s Oxygenation: Volume 1: The Palaeoproterozoic of Fennoscandia as Context for the Fennoscandian Arctic Russia-Drilling Early Earth Project Springer 249--287 VA Melezhik article reuschel2012isotopic 2012 Precambrian Research 192 Elsevier 78--88 M Reuschel VA Melezhik MJ Whitehouse A Lepland AE Fallick H Strauss article Vasconcelos2012 Several geophysical methods have been used for decades for the identification and exploration of impact craters. Most of them are based on seismic, potential fields and electrical data, focusing on exploration of anomalies caused by changes in physical properties or by structures associated with the formation of the crater. Gamma-ray spectrometry is usually not mentioned among the geophysical methods employed in crater studies, although it is known that impact cratering processes cause a number of physical/chemical changes in the country rocks. These changes include the remobilization of hydrothermal fluids which directly modify the composition of target rocks and, subsidiarily, of soils related to these rocks. Therefore, the distribution of radioactive elements K, Th and U has the potential to map such modifications. We present the analysis of gamma-ray signatures at the Serra da Cangalha impact structure, located in northeastern Brazil, using methods for enhancing K anomalies and also the overall gamma-ray signatures. These results provide valuable information on the distinct zones within the crater and might contribute to the understanding of hydrothermal enrichment processes produced as a result of the impact event. Copyright 2012 by the American Geophysical Union. 2012 10.1029/2011GL050525 Geophysical Research Letters 39 Institute of Geosciences, University of Campinas, Rua João Pandiá Calógeras, 51, Campinas, SP 13083-870, Brazil 4 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84857602659&doi=10.1029%2f2011GL050525&partnerID=40&md5=05ba9f86f513485a7b5de5f5a6d774f1 cited By 10 M.A.R. Vasconcelos E.P. Leite A.P. Crósta article Hillers2012 The Taiwan Chelungpu-fault Drilling Project (TCDP) installed a vertical seismic array between 950 and 1270 m depth in an active thrust fault environment. In this paper we analyze continuous noise records of the TCDP array between 1 and 16 Hz. We apply multiple array processing and noise correlation techniques to study the noise source process, properties of the propagation medium, and the ambient seismic wave field. Diurnal amplitude and slowness patterns suggest that noise is generated by cultural activity. The vicinity of the recording site to the excitation region, indicated by a narrow azimuthal distribution of propagation directions, leads to a predominant ballistic propagation regime. This is evident from the compatibility of the data with an incident plane wave model, polarized direct arrivals of noise correlation functions, and the asymmetric arrival shape. Evidence for contributions from scattering comes from equilibrated earthquake coda energy ratios, the frequency dependent randomization of propagation directions, and the existence of correlation coda waves. We conclude that the ballistic and scattered propagation regime coexist, where the first regime dominates the records, but the second is weaker yet not negligible. Consequently, the wave field is not equipartitioned. Correlation signal-to-noise ratios indicate a frequency dependent noise intensity. Iterations of the correlation procedure enhance the signature of the scattered regime. Discrepancies between phase velocities estimated from correlation functions and in-situ measurements are associated with the array geometry and its relative orientation to the predominant energy flux. The stability of correlation functions suggests their applicability in future monitoring efforts. Copyright 2012 by the American Geophysical Union. 2012 English 21699313 10.1029/2011JB008999 Journal of Geophysical Research: Solid Earth 117 Blackwell Publishing Ltd Institut des Sciences de la Terre, Université Joseph Fourier, CNRS, FR-38041 Grenoble, France; Department of Earth Sciences, Institute of Geophysics, National Central University, Jhongli, Taiwan 6 ambient noise; borehole; coda; correlation; drilling; geophysical array; in situ measurement; numerical model; seismic source; seismic wave; signal-to-noise ratio; wave field; wave propagation; wave scattering, Taiwan https://www.scopus.com/inward/record.uri?eid=2-s2.0-84861854258&doi=10.1029%2f2011JB008999&partnerID=40&md5=e03767988b6e09bb8501ef47dd4c2dc2 cited By 19 G. Hillers M. Campillo Y.-Y. Lin K.-F. Ma P. Roux article Spencer2012280 This study aims to assess whether luminescence emission from fault gouge samples from the San Andreas Fault Observatory at Depth (SAFOD) can be used to determine the age distribution of distinct deformation microstructures. Such age determination could help constrain some of the proposed micromechanical models for shear localization in fault gouge, in addition to providing more accurate time constraint on the seismic cycle itself. The mechanism by which previously trapped charge is reset in minerals in fault gouge is thought to be a combination of frictional heating and mechanical deformation, and these processes may be localized to grain surfaces. An added dating complexity specific to deep samples is the high ambient temperature conditions, which act as a barrier to charge storage in lower energy trapping sites. In this work luminescence experiments are being conducted on minerals from whole-rock samples of intact fault gouge from the SAFOD Phase III core. Initial studies indicate (i) the thermal and radiation history of the mineral lattice can be assessed with TL, (ii) trap resetting is evident in both TL and IRSL data, (iii) a small charge-trapping window between drill hole ambient temperature of ∼112 °C and higher energy lattice excitation via rupture events is evident in TL data from ∼300 to 400 °C, and we tentatively link the source of IRSL to TL within this 300-400 °C region, (iv) IRSL data have low natural intensity but good luminescence characteristics, and (v) SAR IRSL D e data have high over-dispersion but demonstrate ages ranging from decades to centuries may be measured. © 2012 Elsevier B.V.. 2012 English 18711014 10.1016/j.quageo.2012.04.023 Quaternary Geochronology 10 280-284 Department of Geology, Kansas State University, Manhattan, KS 66506, United States; Department of Geography and Geosciences, University of Louisville, Louisville, KY 40292, United States; ISTerre, Université Joseph Fourier, Grenoble, France complexity; deformation; fault gouge; fault zone; luminescence dating; microstructure; resetting; rupture; San Andreas Fault, California; San Andreas; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-84863778952&doi=10.1016%2fj.quageo.2012.04.023&partnerID=40&md5=b65c24b3d7de7f06f76ced200a839785 cited By 12 J.Q.G. Spencer J. Hadizadeh J.-P. Gratier M.-L. Doan article Wan20121546 Located at the midpoint of the Asian " airborne dust corridor" , Lake Qinghai receives substantial dust annually, which may impact the biogeochemical cycles of the system. In order to determine quantitatively the flux and chemical contributions of dust to Lake Qinghai sediment, dust samples were collected monthly at two sites surrounding the lake from June 2009 to May 2011. The results demonstrate similar chemical compositions of dust samples to the local loess, implying strong representativeness of regional dust. The average dust deposition flux is 265.7±55.0g/m 2/a, constituting 56.6±11.7% of the modern sediment, approximating to previous estimates (~65%). Contributions of dust-derived elements in the sediment differ substantially, with a minimum of 16.7% for Sr and a maximum of 83.9% for Cu. Among these elements, the contribution of lithophile elements (Na, Al, K, Ti, Mn, Fe and Rb) is close to that of the bulk dust; the contributions of mobile elements (Mg, Ca and Sr) are low, only 16.7% (Sr)-26.1% (Mg), whereas potentially harmful metals (Cu, Zn and Pb) have high contributions (70.3-83.9%). Seasonal variations of elemental inputs indicate that springtime contributions dominate the annual dust fluxes for all elements into the sediment, in agreement with the high dust flux in spring. These observations not only quantify the contribution of dust to the sediment of Lake Qinghai, but also highlight the important role of dust in the accumulation of various elements in the sediment, especially for potentially harmful metals. © 2012 Elsevier Ltd. Article 2012 English 08832927 10.1016/j.apgeochem.2012.03.009 Applied Geochemistry 27 1546 – 1555 8 China; Qinghai; Qinghai Lake; Copper; Lakes; Lead; Manganese; Rubidium; Sedimentology; Sediments; Sodium; Strontium; Airborne dusts; Biogeochemical cycle; Chemical compositions; Dust deposition; Dust flux; Dust samples; Eolian dust; Lake Qinghai; Lithophile elements; Mobile elements; Seasonal variation; biogeochemical cycle; eolian deposit; lacustrine deposit; quantitative analysis; seasonal variation; sediment chemistry; Dust https://www.scopus.com/inward/record.uri?eid=2-s2.0-84862841047&doi=10.1016%2fj.apgeochem.2012.03.009&partnerID=40&md5=61d4298a77b15a48aaef2c97ea7d8a9c Cited by: 28 Dejun Wan Zhangdong Jin Yinxi Wang article Mang2012277 Pyrrhotite from suevite of the 35Ma Chesapeake Bay impact structure (CBIS) shows a shock metamorphism and we report on several mineralogical and magnetic features. Pyrrhotite shows strong brittle deformation with a high density of stacking faults, twinning parallel to the hexagonal (001) planes and average fault distances in the order of 10nm. Although the determination of a superstructure was not possible due to the lattice defects, the reflections of the NiAs subcell, which is typical of all pyrrhotite modifications, were clearly detected. This phase is ferrimagnetic with a Curie temperature (T C) between 350 and 365°C, and suevite with this phase does not show the 34K transition. The most peculiar feature is the low metal/sulfur ratio of 0.81, which indicates a distinctly higher vacancy concentration than for 4C pyrrhotite and a composition close to smythite (Fe 9S 11). This phase carries a stable natural remanent magnetization and is relatively hard magnetic. Steep inclinations of the natural remanent magnetization vector, however, suggest that this phase has been remagnetized by the drilling process. A possible explanation is the magnetic domain size of faultless areas of about 10nm in diameter, which is at the lower limit of the single domain size near the threshold, below which superparamagnetic behavior occurs. The low thermal stability of this phase excludes postshock heating above 300°C for the suevite of the CBIS. Our results imply that the iron-deficient pyrrhotite is produced by shock metamorphism, although an iron loss due to shock has never been reported before for pyrrhotite. © 2012 The Meteoritical Society. 2012 English 10869379 10.1111/j.1945-5100.2012.01329.x Meteoritics and Planetary Science 47 277-295 Institut für Angewandte Geowissenschaften, Karlsruher Institut für Technologie, Adenauerring 20, Geb. 50.40, 76131 Karlsruhe, Germany; Bayerisches Geoinstitut, University of Bayreuth, 95440 Bayreuth, Germany; Museum für Naturkunde, Leibniz-Institut an der Humboldt Universität zu Berlin, Invalidenstraße 43, 10115 Berlin, Germany 2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84856719076&doi=10.1111%2fj.1945-5100.2012.01329.x&partnerID=40&md5=b15cb147d7127c1f2a4996abcf27d52d cited By 8 C. Mang A. Kontny D. Harries F. Langenhorst L. Hecht article Delahunty2012641 A deep core drilling project focused on evaluating the geothermal potential of the Snake River Plains in southern Idaho. Slim-hole continuous diamond coring and associated geophysical surveys were used to sample different geothermal environments. Three locations were drilled with target depths as follows: Kimama 1915 m, Kimberly 1959 m, and Mountain Home 1821 m. All total depths were accomplished or exceeded. A continuous core sample was produced and down-hole temperature while drilling was collected. Conference paper 2012 English 978-162276434-1 01935933 Transactions - Geothermal Resources Council 36 1 641 – 647 DOSECC, Salt Lake City, UT, United States; Utah State University, Logan, UT, United States Core drilling; Geothermal fields; Geothermal; Kimama (Idaho); Kimberly (Idaho); Mountain Home (Idaho); Slim-hole coring; Snake river plains; Wireline; Rivers https://www.scopus.com/inward/record.uri?eid=2-s2.0-84876266974&partnerID=40&md5=834e838891feea9c2b0f84755d4a21a8 Cited by: 4 Chris Delahunty Dennis L. Nielson John W. Shervais article Tomonaga201299 In this work we present noble-gas concentration profiles measured in the water column and in the sediment pore water of the Earth's largest soda lake: Lake Van (eastern Anatolia, Turkey). The concentrations of noble gases (in particular Ar, Kr, and Xe) in the water body deviate significantly from the expected equilibrium concentrations calculated from the in situ temperature and salinity using existing solubility functions for seawater. The specific chemical composition of the water of the soda lake seems to be responsible for the observed deviations. Our measurements allow the identification and quantification of salinity factors that can be applied to correctly calculate the noble-gas equilibrium concentrations for the lake. These salinity factors provide a solid and robust empirical basis for the interpretation of noble-gas concentration signals measured in the sediment pore water of Lake Van in terms of palaeosalinity and palaeotemperature. © 2012 Elsevier Ltd. 2012 English 13679120 10.1016/j.jseaes.2012.05.011 Journal of Asian Earth Sciences 59 99-107 Eawag, Swiss Federal Institute of Aquatic Science and Technology, Department of Water Resources and Drinking Water, Überlandstrasse 133, CH-8600 Dübendorf, Switzerland; Institute of Biogeochemistry and Pollutant Dynamics, Swiss Federal Institute of Technology (ETH), CH-8092 Zurich, Switzerland; Institute of Geochemistry and Petrology, Swiss Federal Institute of Technology (ETH), CH-8092 Zurich, Switzerland chemical composition; concentration (composition); empirical analysis; noble gas; paleoclimate; paleosalinity; paleotemperature; porewater; salinity; temperature; water column, Lake Van; Turkey https://www.scopus.com/inward/record.uri?eid=2-s2.0-84867396520&doi=10.1016%2fj.jseaes.2012.05.011&partnerID=40&md5=20d49d6f5b6844b415729a2226868e8e cited By 20 Y. Tomonaga R. Blättler M.S. Brennwald R. Kipfer article An2012 Two atmospheric circulation systems, the mid-latitude Westerlies and the Asian summer monsoon (ASM), play key roles in northern-hemisphere climatic changes. However, the variability of the Westerlies in Asia and their relationship to the ASM remain unclear. Here, we present the longest and highest-resolution drill core from Lake Qinghai on the northeastern Tibetan Plateau (TP), which uniquely records the variability of both the Westerlies and the ASM since 32ĝ€...ka, reflecting the interplay of these two systems. These records document the anti-phase relationship of the Westerlies and the ASM for both glacial-interglacial and glacial millennial timescales. During the last glaciation, the influence of the Westerlies dominated; prominent dust-rich intervals, correlated with Heinrich events, reflect intensified Westerlies linked to northern high-latitude climate. During the Holocene, the dominant ASM circulation, punctuated by weak events, indicates linkages of the ASM to orbital forcing, North Atlantic abrupt events, and perhaps solar activity changes. Article 2012 English 20452322 10.1038/srep00619 Scientific Reports 2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84866130315&doi=10.1038%2fsrep00619&partnerID=40&md5=d6e5a452d19a8e578eae4b3b0673bb14 Cited by: 594; All Open Access, Gold Open Access, Green Open Access ZhiSheng An Steven M. Colman Weijian Zhou Xiaoqiang Li Eric T. Brown A. J. Timothy Jull Yanjun Cai Yongsong Huang Xuefeng Lu Hong Chang YouGui Song Youbin Sun Hai Xu Weiguo Liu Zhangdong Jin Xiaodong Liu Peng Cheng Yu Liu Li Ai Xiangzhong Li Xiuju Liu Libin Yan Zhengguo Shi Xulong Wang Feng Wu Xiaoke Qiang Jibao Dong Fengyan Lu Xinwen Xu article Majorowicz2012667 Atmospheric methane from episodic gas hydrate (GH) destabilization, the "clathrate gun" hypothesis, is proposed to affect past climates, possibly since the Phanerozoic began or earlier. In the terrestrial Beaufort-Mackenzie Basin (BMB), GHs occur commonly below thick ice-bearing permafrost (IBP), but they are rare within it. Two end-member GH models, where gas is either trapped conventionally (Case 1) or where it is trapped dynamically by GH formation (Case 2), were simulated using profile (1-D) models and a 14 Myr ground surface temperature (GST) history based on marine isotopic data, adjusted to the study setting, constrained by deep heat flow, sedimentary succession conductivity, and observed IBP and Type I GH contacts in Mallik wells. Models consider latent heat effects throughout the IBP and GH intervals. Case 1 GHs formed at ∼0.9 km depth only ∼1 Myr ago by in situ transformation of conventionally trapped natural gas. Case 2 GHs begin to form at ∼290-300 m ∼6 Myr ago in the absence of lithological migration barriers. During glacial intervals Case 2 GH layers expand both downward and upward as the permafrost grows downward through and intercalated with GHs. The distinctive model results suggest that most BMB GHs resemble Case 1 models, based on the observed distinct and separate occurrences of GHs and IBP and the lack of observed GH intercalations in IBP. Case 2 GHs formed >255 m, below a persistent ice-filled permafrost layer that is as effective a seal to upward methane migration as are Case 1 lithological seals. All models respond to GST variations, but in a delayed and muted manner such that GH layers continue to grow even as the GST begins to increase. The models show that the GH stability zone history is buffered strongly by IBP during the interglacials. Thick IBP and GHs could have persisted since ∼1.0 Myr ago and ∼4.0 Myr ago for Cases 1 and 2, respectively. Offshore BMB IBP and GHs formed terrestrially during Pleistocene sea level low stands. Where IBP is sufficiently thick, both IBP and GHs persist even where inundated by a Holocene sea level rise and both are also expected to persist into the next glacial even if atmospheric CO2 doubles. We do not address the "clathrate gun" hypothesis directly, but our models show that sub-IBP GHs respond to, rather than cause GST changes, due to both how GST changes propagates with depth and latent heat effects. Models show that many thick GH accumulations are prevented from contributing methane to the atmosphere, because they are almost certainly trapped below either ice-filled IBP or lithological barriers. Where permafrost is sufficiently thick, combinations of geological structure, thermal processes and material properties make sub-IBP GHs unlikely sources for significant atmospheric methane fluxes. Our sub-IBP GH model histories suggest that similar models applied to other GH settings could improve the understanding of GHs and their potential to affect climate. © 2012 Author(s). 2012 English 18149324 10.5194/cp-8-667-2012 Climate of the Past 8 667-682 Department of Physics, University of Alberta, NGC 105 Carlson Close, Edmonton, AB, T6R 2J8, Canada; Institute of Geophysics, Czech Academy of Sciences, 141-31 Praha 4, Czech Republic; Geological Survey of Canada 3303, 33rd St. NW, Calgary, AB, T2L2A7, Canada 2 carbon dioxide; climate variation; gas hydrate; heat flux; Holocene; interglacial; lithology; methane; natural gas; paleoatmosphere; paleoclimate; permafrost; Phanerozoic; sea level change; surface temperature, Arctic Ocean; Beaufort Sea; Beaufort-Mackenzie Basin; Canada; Canadian Arctic, Calluna vulgaris https://www.scopus.com/inward/record.uri?eid=2-s2.0-84859333031&doi=10.5194%2fcp-8-667-2012&partnerID=40&md5=39cfa92bb4aae9dd116a0b4500b8e057 cited By 14 J. Majorowicz J. Šafanda K. Osadetz book Grieve201290 2012 10.1002/9781118447307.ch7 Impact Cratering: Processes and Products 90-105 Departments of Earth Sciences, Departments of Physics and Astronomy, Western University, 1151 Richmond Street, London, ON N6A 5B7, Canada; Earth Sciences Sector, Natural Resources Canada, Ottawa, Ontario K1A 0E8, Canada https://www.scopus.com/inward/record.uri?eid=2-s2.0-84886332471&doi=10.1002%2f9781118447307.ch7&partnerID=40&md5=4755773cc9b1cf56db9e9f303b55dea7 cited By 17 R.A.F. Grieve A.M. Therriault book Kirsimäe201276 2012 10.1002/9781118447307.ch6 Impact Cratering: Processes and Products 76-89 Department of Geology, University of Tartu, Ravila 14a, Tartu 50411, Estonia; Departments of Earth Sciences, Departments of Physics and Astronomy, Western University, 1151 Richmond Street, London, ON N6A 5B7, Canada https://www.scopus.com/inward/record.uri?eid=2-s2.0-84883244975&doi=10.1002%2f9781118447307.ch6&partnerID=40&md5=617940f70341a4e62a7bb5a88648b1d3 cited By 20 K. Kirsimäe G.R. Osinski article Fischer20121019 Geodynamic activity in the area of West Bohemia is typified by the occurrence of earthquake swarms, Quaternary volcanism and high flux of mantle-derived CO2. The highest swarm activity occurs beneath the eastern edge of the Cheb basin, which is delineated by the NW-SE trending morphologically pronounced Mariánské Lázně Fault (MLF) controlling the formation of the basin. The previous trenching survey across the MLF zone has identified several fault strands with possible Quaternary activity. In this paper we present the results of the geophysical survey focused to trace the faults signatures in geophysical sections and to build an image of near surface tectonics. The method of electric resistivity tomography (ERT) along two profiles parallel to the trench identified a strong resistivity contrast between the bodies of sandy gravels in the middle and conductive clayey sands to the west and weathered crystalline basement to the east. The 2-D ground penetration radar (GPR) sections show direct correlation of reflections with lithological boundaries identified in the trench. As expected, the GPR signal amplitudes increase with the resistivities found in the ERT sections. Two of the four faults identified in the trench are indicated in the resistivity and GPR sections. A 3-D GPR measurement has identified a spot of high amplitudes elongated parallel to the MLF trend, which coincides with the high resistivity body. To improve the signal-to-noise ratio of the time slices we stacked the GPR time slices within vertically homogeneous blocks. This provided a contrast image of the sand-gravel body including its boundaries in three dimensions. The detailed analysis of the 3-D GPR cube revealed additional fault that limits the highly reflective sands and appears to be offset by another younger fault. Our results suggest a complex fault pattern in the studied area, which deserves a further study. © 2012 Institute of Geophysics of the ASCR, v.v.i. Article 2012 English 00393169 10.1007/s11200-012-0825-z Studia Geophysica et Geodaetica 56 Kluwer Academic Publishers 1019 – 1036 4 Bohemia; Czech Republic; earthquake swarm; electrical resistivity; fault zone; geodynamics; ground penetrating radar; lithology; Quaternary; signal-to-noise ratio; three-dimensional modeling; tomography; trend analysis; two-dimensional modeling; volcanism https://www.scopus.com/inward/record.uri?eid=2-s2.0-84870856355&doi=10.1007%2fs11200-012-0825-z&partnerID=40&md5=ed2fff6455ae6d6221069cbd495f0ba1 Cited by: 16 Tomáš Fischer Petra Štěpančíková Magda Karousová Petr Tábořík Christina Flechsig Mahmoud Gaballah article Litt201295 The Dead Sea, located at the deepest place on continent and between the subtropical Mediterranean zone and the desert, reflects in its water composition and levels, and sedimentary records the hydrological conditions in the southern Levant region. Temporal variations in rainfall and temperatures of the Holocene Levant are reconstructed here from pollen data recovered from a sediment core drilled at the Ein Gedi shore, applying a novel biome model based on Bayesian statistics. Our results suggest that the region was arid and warm in the early Holocene period (~10-6.5 ka cal BP), wetter and colder in the mid Holocene (6.3-3.3 ka cal BP), and drier and warmer in the late Holocene (~3.2 ka cal BP to present). These periods comprise multi-centennial climate cycles that are characterized by rapid changes in temperature and precipitation reflecting Sea Surface Temperature (SST) and atmospheric conditions over the Atlantic Ocean. The pollen record responds within a short time interval to the climate conditions and marks rapid shifts from Mediterranean to desert environmental conditions and back in the southern Levant region. We also evaluate our results in the light of possible disturbances of the natural vegetation, e.g. the possibility of forest decrease, since the Neolithic. © 2012 Elsevier Ltd. 2012 English 02773791 10.1016/j.quascirev.2012.06.012 Quaternary Science Reviews 49 95-105 Steinmann Institute of Geology, Mineralogy and Paleontology, University of Bonn, Nussallee 8, 53115 Bonn, Germany; Meteorological Institute, University of Bonn, Auf dem Hügel 20, 53121 Bonn, Germany; Paleobotany Research Group, University of Münster, Schlossplatz 9, 48143 Münster, Germany; Geological Survey of Israel, 30 Malkhe Israel Street, 85501 Jerusalem, Israel Atlantic Ocean; Atmospheric conditions; Bayesian statistics; Climate condition; Climate cycle; Dead sea; Environmental conditions; Holocene climate variability; Holocenes; Hydrological condition; Late Holocene; Model-based OPC; Natural vegetation; Near East; Paleoclimatology; Palynology; Pollen data; Rapid shifts; Sea surface temperature (SST); Sediment core; Sedimentary records; Short time intervals; Temporal variation; Water composition, Sedimentology; Structural analysis, Climatology, Bayesian analysis; climate conditions; climate cycle; climate variation; desert; environmental disturbance; Holocene; Neolithic; paleoclimate; paleotemperature; palynology; precipitation (climatology); quantitative analysis; reconstruction; sea surface temperature; sediment core; temporal variation; vegetation dynamics; water level; water quality, Dead Sea; En Gedi; Levant; Mediterranean Region; Occupied Territories; West Bank https://www.scopus.com/inward/record.uri?eid=2-s2.0-84864412881&doi=10.1016%2fj.quascirev.2012.06.012&partnerID=40&md5=96b2304345def2e4b6ff1337b854b5fe cited By 125 T. Litt C. Ohlwein F.H. Neumann A. Hense M. Stein article Urrutia-Fucugauchi2012769 Initial results of a thermal treatment study on the anisotropy of magnetic susceptibility (AMS) of impact breccias from Chicxulub crater are used to investigate the nature of the magnetic fabrics. Chicxulub impact breccias are heterogeneous materials, with carbonate, basement and melt clasts within carbonate-rich or melt-rich matrix. Samples studied come from the carbonate-rich basal unit Lower Suevite in the Yaxcopoil-1 borehole impactite sequence (core depth interval: 885-895 m). The Lower Suevite is characterized by mixed prolate and oblate ellipsoids with shallow to steep principal susceptibility axes, which had been related to emplacement as an excavation flow with ground-surge components during the early cratering stages. Thermal treatment results in changes in the fabrics with a tendency to oblate fabrics. Stepwise thermal treatment up to 700°C reveals different behaviors for the oblate, neutral and prolate fabrics marked by changes in AMS parameters and principal susceptibility axis orientations. A sample with oblate fabrics and vertical minimum axes showed an increase of magnetic susceptibility at high temperatures, indicating formation of secondary magnetite and fabric enhancement. A sample with neutral ellipsoid showed heating-induced changes towards oblate fabrics and vertical minimum susceptibility axes. Samples characterized by prolate ellipsoids with horizontal maximum axes showed no directional changes. In a sample with apparent intermediate or inverse fabrics, vertical maximum axes showed changes to horizontal inclinations, with the intermediate and maximum axes switching positions. Changes induced by stepwise thermal treatment appear useful to characterize the fabrics of impact lithologies. Further investigation of heating-induced effects in mineralogy, grain size and textural changes is, however, required to relate the different behaviors observed after stepwise thermal treatment with the magnetic mineralogy and emplacement mode of the breccias. © 2012 Institute of Geophysics of the ASCR, v.v.i. 2012 10.1007/s11200-010-0292-3 Studia Geophysica et Geodaetica 56 769-787 Programa Universitario de Perforaciones en Oceanos y Continentes, Laboratorio de Paleomagnetismo y Paleoambientes, Instituto de Geofisica, Universidad Nacional Autonoma de Mexico, D. Coyoacan, 04510 Mexico, Mexico 3 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84864278897&doi=10.1007%2fs11200-010-0292-3&partnerID=40&md5=4bb9b77e05a22b2ed7ed983902eef564 cited By 3 J. Urrutia-Fucugauchi M. Delgadillo-Peralta L. Pérez-Cruz M. Velasco-Villarreal article Nielson2012727 The Hotspot project has sampled three different geothermal environments in the Snake River Plain (SRP) in Idaho. The project used slim-hole wire line coring in conjunction with a bottom hole temperature probe developed by DOSECC. The first hole at Kimama in the center of the eastern SRP was cored to a depth of 1,915 m. Temperature measurements showed the SRP fresh water aquifer extends to a depth of 965 m and masks the underlying temperature gradient of 74.5°C/Km. A core hole in the town of Kimberly reached a depth of 1,959 m and demonstrated a resource of >50°C from 800 m to the bottom of the hole. A core hole at Mountain Home AFB in the eastern SRP reached a depth of 1,821 m and documents an intermediate- to high-temperature resource. 2012 English 9781622764341 01935933 Transactions - Geothermal Resources Council 36 1 727-730 DOSECC, Salt Lake City, UT, United States; Utah State University, Logan, UT, United States Air Force Base; Bottom-hole temperatures; ID; Kimama; Kimberly; Slim-hole coring; Snake River, Aquifers; Geothermal wells; Rivers; Temperature measurement; Thermal gradients, Geothermal fields https://www.scopus.com/inward/record.uri?eid=2-s2.0-84876209584&partnerID=40&md5=1dd7f4860dcaab17e56aa3d71bdf790f cited By 13 D.L. Nielson C. Delahunty J.W. Shervais article gang2012geological 2012 Geoscience 26 741 4 Han Gang ZHANG Wen-Jing HUANG Qing-Hua MENG Yuan-Lin article Shervais2012767 The Snake River volcanic province (SRP) overlies a thermal anomaly that extends deep into the mantle; it represents one of the highest heat flow provinces in North America. The primary goal of this project is to evaluate geothermal potential in three distinct settings: (1) Kimama site: inferred high sub-aquifer geothermal gradient associated with the intrusion of mafic magmas, (2) Kimberly site: a valley-margin setting where surface heat flow may be driven by the up-flow of hot fluids along buried caldera ring-fault complexes, and (3) Mountain Home site: a more traditional fault-bounded basin with thick sedimentary cover. The Kimama hole, on the axial volcanic zone, penetrated 1912 m of basalt with minor intercalated sediment; no rhyolite basement was encountered. Temperatures are isothermal through the aquifer (to 960 m), then rise steeply on a super-conductive gradient to an estimated bottom hole temperature of ∼98°C. The Kimberly hole is on the inferred margin of a buried rhyolite eruptive center, penetrated rhyolite with intercalated basalt and sediment to a TD of 1958 m. Temperatures are isothermal at 55-60°C below 400 m, suggesting an immense passive geothermal resource. The Mountain Home hole is located above the margin of a buried gravity high in the western SRP. It penetrates a thick section of basalt and lacustrine sediment overlying altered basalt flows, hyaloclastites, and volcanic sediments, with a TD of 1821 m. Artesian flow of geothermal water from 1745 m depth documents a power-grade resource that is now being explored in more detail. In-depth studies continue at all three sites, complemented by high-resolution gravity, magnetic, and seismic surveys, and by downhole geophysical logging. Conference paper 2012 English 978-162276434-1 01935933 Transactions - Geothermal Resources Council 36 2 767 – 772 Department of Geology, Utah State University, Logan, UT, United States; DOSECC, Inc., Salt Lake City, UT, United States; Department of Geological Sciences, Brigham Young University, Provo, UT, United States; US Geological Survey, Denver, CO, United States; Department of Physics, University of Alberta, Edmonton, AB, Canada; Center for Geophysical Investigation of the Shallow Subsurface, Boise State University, Boise, ID, United States; Roy Huffington Dept. of Earth Sciences, Southern Methodist University, Dallas, TX, United States; US Geological Survey, Menlo Park, CA, United States Aquifers; Basalt; Geothermal fields; Geothermal wells; Granite; Isotherms; Natural resources exploration; Rivers; Sedimentology; Volcanoes; Bottom hole temperatures; Downhole geophysical logging; Geothermal resources; Hot spot; Idaho; Lacustrine sediments; Rhyolite; Snake river plains; Sediments https://www.scopus.com/inward/record.uri?eid=2-s2.0-84876233464&partnerID=40&md5=c4e66fa8a0f5f878b9f4ba46fe518258 Cited by: 14 John W. Shervais Dennis Nielson James P. Evans Thomas Lachmar Eric H. Christiansen Lisa Morgan W. C. Pat Shanks Christopher Delahunty Lee M. Liberty David D. Blackwell Jonathan M. Glen James A. Kessler Katherine E. Potter Marlon M. Jean Christopher J. Sant Thomas G. Freeman conference Gloaguen2012 The decrease in conventional gas reservoir new discoveries combined with the increase of the market and improvement of the exploitation technologies push the industry to look for unconventional gas resources. Gas hydrates are one of the largest unconventional resource but also one of the less known. In this study, we use a modified bayesian algorithm in order to simulated gas hydrate grades at Mallik, TNO, Canada constrained by 3D seismic acoustic impedances. The results are validated using a high resolution seismic tomographic inversion. Even with the poor quality 3D seismic data, the proposed method is found to be very robust to estimate gas hydrate grades at Mallik. 2012 English 10.3997/2214-4609.20142887 Integrated Reservoir Modelling: Are We Doing it Right? European Association of Geoscientists and Engineers, EAGE INRS-ETE, France; École Polytechnique, France Acoustic impedance; Energy resources; Gases; Hydration; Reservoir management; Resource valuation; Seismology, 3D seismic data; Bayesian algorithms; Gas hydrate reservoir; Gas reservoir; High resolution seismic; Tomographic inversion; Unconventional gas; Unconventional resources, Gas hydrates https://www.scopus.com/inward/record.uri?eid=2-s2.0-85086490438&doi=10.3997%2f2214-4609.20142887&partnerID=40&md5=4cb8fdae978db7a4e6226bb6ceaa6f00 cited By 0 E.G. Gloaguen C.D.B. Dubreuil-Boisclair B.G. Giroux D.M. Marcotte article Breckenridge2012615 The U.S. Air Force is facing a number of challenges as it moves into the future, one of the biggest being how to provide safe and secure energy to support base operations. A team of scientists and engineers met at Mountain Home Air Force Base near Boise, Idaho, to discuss the possibility of exploring for geothermal resources under the base. The team identified that there was a reasonable potential for geothermal resources based on data from an existing well. In addition, a regional gravity map helped identify several possible locations for drilling a new well. The team identified several possible sources of funding for this well - the most logical being to use U.S. Department of Energy funds to drill the upper half of the well and U.S. Air Force funds to drill the bottom half of the well. The well was designed as a slimhole well in accordance with State of Idaho Department of Water Resources rules and regulations. Drilling operations commenced at the Mountain Home site in July of 2011 and were completed in January of 2012. Temperatures increased gradually, especially below a depth of 2000 ft. Temperatures increased more rapidly below a depth of 5500 ft. The bottom of the well is at 5976 ft, where a temperature of about 140°C was recorded. The well flowed artesian from a depth below 5600 ft, until it was plugged off with drilling mud. Core samples were collected from the well and are being analyzed to help understand permeability at depth. Additional tests using a televiewer system will be run to evaluate orientation and directions at fractures, especially in the production zone. A final report on the well exploitation will be forthcoming later this year. The Air Force will use it to evaluate the geothermal resource potential for future private development options at Mountain Home AFB. 2012 English 9781622764341 01935933 Transactions - Geothermal Resources Council 36 1 615-619 Energy and Environmental Sciences Directorate, Idaho National Laboratory, Idaho Falls, ID, United States; DOSECC, Salt Lake City, UT, United States; Department of Geology, Utah State University, Logan, UT, United States Air Force Base; Deep slimhole cores; Department of Water Resources; Geothermal; Resource assessments; Rules and regulations; Scientists and engineers; U.S. Department of Energy, Drills; Geothermal fields; Landforms; Oil well drilling, Military aviation https://www.scopus.com/inward/record.uri?eid=2-s2.0-84876279676&partnerID=40&md5=0949eaa3e39c446a1710c892c1c03a5e cited By 5 R.P. Breckenridge D.L. Nielson J.W. Shervais T.R. Wood article cp-8-1897-2012 The combination of permafrost history and dynamics, lake level changes and the tectonical framework is considered to play a crucial role for sediment delivery to El'gygytgyn Crater Lake, NE Russian Arctic. The purpose of this study is to propose a depositional framework based on analyses of the core strata from the lake margin and historical reconstructions from various studies at the site. A sedimentological program has been conducted using frozen core samples from the 141.5 m long El'gygytgyn 5011-3 permafrost well. The drill site is located in sedimentary permafrost west of the lake that partly fills the El'gygytgyn Crater. The total core sequence is interpreted as strata building up a progradational alluvial fan delta. Four macroscopically distinct sedimentary units are identified. Unit 1 (141.5-117.0 m) is comprised of ice-cemented, matrix-supported sandy gravel and intercalated sandy layers. Sandy layers represent sediments which rained out as particles in the deeper part of the water column under highly energetic conditions. Unit 2 (117.0-24.25 m) is dominated by ice-cemented, matrix-supported sandy gravel with individual gravel layers. Most of the Unit 2 diamicton is understood to result from alluvial wash and subsequent gravitational sliding of coarse-grained (sandy gravel) material on the basin slope. Unit 3 (24.25-8.5 m) has ice-cemented, matrix-supported sandy gravel that is interrupted by sand beds. These sandy beds are associated with flooding events and represent near-shore sandy shoals. Unit 4 (8.5-0.0 m) is ice-cemented, matrix-supported sandy gravel with varying ice content, mostly higher than below. It consists of slope material and creek fill deposits. The uppermost metre is the active layer (i.e. the top layer of soil with seasonal freeze and thaw) into which modern soil organic matter has been incorporated. The nature of the progradational sediment transport taking place from the western and northern crater margins may be related to the complementary occurrence of frequent turbiditic layers in the central lake basin, as is known from the lake sediment record. Slope processes such as gravitational sliding and sheet flooding occur especially during spring melt and promote mass wasting into the basin. Tectonics are inferred to have initiated the fan accumulation in the first place and possibly the off-centre displacement of the crater lake. © Author(s) 2012. 2012 English 18149324 10.5194/cp-8-1897-2012 Climate of the Past 8 1897-1911 Alfred Wegener Institute for Polar and Marine Research, Telegrafenberg, 14473 Potsdam, Germany; Arctic and Antarctic Research Institute, Bering Street 38, 199397 St.-Petersburg, Russian Federation; St. Petersburg State University, Faculty of Geography and Geoecology, 10 line V.O., 33, 199178 St.-Petersburg, Russian Federation; Cologne University, Institute for Geology and Mineralogy, Zülpicher Str., 50674 Cologne, Germany 6 alluvial fan; crater lake; depositional environment; displacement; flooding; matrix; nearshore environment; permafrost; reconstruction; sediment core; sediment transport; sedimentology; sliding; turbidity; water column, Chukchi; Elgygytgyn Lake; Russian Federation https://cp.copernicus.org/articles/8/1897/2012/ cited By 15 G. Schwamborn G. Fedorov N. Ostanin L. Schirrmeister A. Andreev Party article Sutherland20121143 Rock damage during earthquake slip affects fluid migration within the fault core and the surrounding damage zone, and consequently coseismic and postseismic strength evolution. Results from the first two boreholes (Deep Fault Drilling Project DFDP-1) drilled through the Alpine fault, New Zealand, which is late in its 200-400 yr earthquake cycle, reveal a &gt;50-m-thick "alteration zone" formed by fluid-rock interaction and mineralization above background regional levels. The alteration zone comprises cemented low-permeability cataclasite and ultramylonite dissected by clay-filled fractures, and obscures the boundary between the damage zone and fault core. The fault core contains a &lt;0.5-m-thick principal slip zone (PSZ) of low electrical resistivity and high spontaneous potential within a 2-m-thick layer of gouge and ultracataclasite. A 0.53 MPa step in fluid pressure measured across this zone confirms a hydraulic seal, and is consistent with laboratory permeability measurements on the order of 10-20 m2. Slug tests in the upper part of the boreholes yield a permeability within the distal damage zone of ~10-14 m2, implying a six-orders-of-magnitude reduction in permeability within the alteration zone. Low permeability within 20 m of the PSZ is confirmed by a subhydrostatic pressure gradient, pressure relaxation times, and laboratory measurements. The low-permeability rocks suggest that dynamic pressurization likely promotes earthquake slip, and motivates the hypothesis that fault zones may be regional barriers to fluid flow and sites of high fluid pressure gradient. We suggest that hydrogeological processes within the alteration zone modify the permeability, strength, and seismic properties of major faults throughout their earthquake cycles. © 2012 Geological Society of America. 2012 English 00917613 10.1130/G33614.1 Geology 40 1143-1146 GNS Science, PO Box 30368, Lower Hutt 5040, New Zealand; University of Otago, PO Box 56, Dunedin 9054, New Zealand; Victoria University of Wellington, PO Box 600, Wellington 6140, New Zealand; GNS Science, Private Bag 1930, Dunedin 9054, New Zealand; Institute of Earth Science and Engineering, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand; University of Liverpool, Merseyside L69 3GP, United Kingdom; University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand; Istituto Nazionale di Geofisica e Vulcanologia, Rome 00143, Italy; University of Southampton, Southampton, SO14 3ZH, United Kingdom; MARUM (Center for Marine Environmental Sciences), University of Bremen, PO Box 330440, 28344 Bremen, Germany 12 Alpine Faults; Alteration zones; Cataclasite; Damage zones; Deep fault; Drilling projects; Earthquake slip; Electrical resistivity; Fault core; Fault zone; Fluid control; Fluid migration; Fluid pressure gradient; Fluid pressures; Fluid-rock interaction; Hydraulic seals; Hydrogeological; Laboratory measurements; Low permeability; New zealand; Permeability measurements; Pressure relaxation; Regional barriers; Regional levels; Rock damage; Seismic properties; Slip zones; Slug test; Spontaneous potentials, Boring; Clay alteration; Earthquakes; Electric conductivity; Pressure gradient; Rock drilling, Faulting, cataclasite; coseismic process; drilling; earthquake rupture; electrical resistivity; fault slip; fault zone; fluid pressure; mineralization; mylonite; permeability; postseismic process; pressure gradient, Alpine Fault Zone; New Zealand; South Island https://www.scopus.com/inward/record.uri?eid=2-s2.0-84872136908&doi=10.1130%2fG33614.1&partnerID=40&md5=6686c9fb0f3aae0872de49006739b05f cited By 122 R. Sutherland V.G. Toy J. Townend S.C. Cox J.D. Eccles D.R. Faulkner D.J. Prior R.J. Norris E. Mariani C. Boulton B.M. Carpenter C.D. Menzies T.A. Little M. Hasting G.P. De Pascale R.M. Langridge H.R. Scott Z. Reid Lindroos B. Fleming J. Kopf article Savchenko201231 The stressed state of the rock mass in the area of the Outokumpu deep drill hole, Finland, was investigated by the boundaryelement method in three mutually orthogonal planes with regard for the massif geological structure. It was found that subhorizontal components of the stress field are determined by tectonic forces acting on the boundaries of the European part of the Eurasian lithospheric plate. In the drill hole vertical section the widest variations of this field gradient occur at the depths of an ophiolite sequence in the range of 1.8-2.0 km. Article 2012 English 12149705 Acta Geodynamica et Geomaterialia 9 31 – 42 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84859167332&partnerID=40&md5=1b5dadc38e3abc6dd3400586d7e625a0 Cited by: 2 Stepan Savchenko Feliks Gorbatsevich article Bulut201217 We present results on imaging contrast of seismic velocities across the Mudurnu segment of the North Anatolian Fault Zone (NAFZ) in northwestern Turkey with polarization analysis of early P waveforms generated by near-fault seismicity and recorded by near-fault stations. The analysis uses changes in motion polarity from fault-normal to source-receiver directions to identify early-arriving fault zone head waves on the slow side of the fault, and measure the arrival times of the head and direct P waves. The moveout between the head and direct waves with increasing source-receiver distance along the fault provides an estimate of the average contrast of seismic velocities across the fault. The results indicate that the average contrast of P wave velocities across the Mudurnu segment of the NAFZ is at least 6%, with the south block being the faster side. The findings provide a basis for deriving improved event locations, focal mechanisms and estimated shaking hazard associated with earthquakes on the fault. The analysis technique can be used in other fault zones monitored with sparse seismic instrumentation. © 2012 Elsevier B.V.. 2012 English 0012821X 10.1016/j.epsl.2012.02.001 Earth and Planetary Science Letters 327-328 17-22 Helmholtz-Zentrum Potsdam, Deutsches Geo ForschungsZentrum, Telegrafenberg, 14473 Potsdam, Germany; Department of Earth Sciences, University of Southern California, Los Angeles, CA 90089-0740, United States Analysis techniques; Arrival time; Bi-material interfaces; Direct waves; Event location; Fault zone; Focal mechanism; Head waves; Imaging contrast; Moveout; Near-fault; North Anatolian Fault; North Anatolian Fault Zone; Northwestern Turkey; P waves; P-wave velocity; Polarization analysis; Seismic instrumentation; Seismic velocities; Wave forms, Polarization, Seismic waves, fault zone; focal mechanism; hazard assessment; imaging method; monitoring; normal fault; North Anatolian Fault; P-wave; seismic source; seismic velocity; seismicity; wave velocity; waveform analysis, Turkey https://www.scopus.com/inward/record.uri?eid=2-s2.0-84857467076&doi=10.1016%2fj.epsl.2012.02.001&partnerID=40&md5=fc1c425575c5cca551624355b5b2a752 cited By 47 F. Bulut Y. Ben-Zion M. Bohnhoff article Kukkonen2012WC213 Seismic reflection data was applied to a study of the upper crustal structures in the Outokumpu mining and exploration area in eastern Finland. The Cu-Co-Zn sulfide ore deposits of the Outokumpu area are hosted by Palaeoproterozoic ophiolite-derived altered ultrabasic rocks (serpentinite, skarn rock, and quartz rock) and black schist within turbiditic mica schist. Mining in the Outokumpu area has produced a total of 36 Mt of ore from three historical and one active mine. Seismic data comprises 2D vibroseis data surveyed along a network of local roads. The seismic sections provide a comprehensive 3D view of the reflective structures. Acoustic rock properties from downhole logging and synthetic seismograms indicate that the strongly reflective packages shown in the seismic data can be identified as the host-rock environments of the deposits. Reflectors show excellent continuity along the structural grain of the ore belt, which allows correlating reflectors with surface geology, magnetic map, and drilling sections into a broad 3D model of the ore belt. Massive ores have acoustic properties that make them directly detectable with seismic reflection methods assuming the deposit size is sufficient for applied seismic wavelengths. The seismic data revealed numerous interesting high-amplitude reflectors within the interpreted host-rock suites potentially coinciding with sulfides. © 2012 Society of Exploration Geophysicists. Article 2012 English 00168033 10.1190/geo2012-0029.1 Geophysics 77 Society of Exploration Geophysicists WC213–WC222 5 Finland; Outokumpu; Pohjois-Karjala; 3D modeling; Acoustic impedance; Acoustic logging; Cobalt alloys; Cobalt compounds; Copper alloys; Copper compounds; Deposits; Geophysical prospecting; Magnesite; Mica; Mica deposits; Ores; Reflection; Seismic response; Seismic waves; Structural geology; Sulfur compounds; Ternary alloys; Zinc alloys; Zinc deposits; Zinc sulfide; Europe; High resolution seismic; Reflective structure; Seismic impedance; Seismic reflection data; Seismic reflection method; Synthetic seismogram; Vibroseis; acoustic property; cobalt; copper; crustal structure; host rock; logging (geophysics); massive sulfide; mica; mining; ophiolite; ore deposit; reflectivity; schist; seismic data; seismic reflection; seismic wave; seismogram; upper crust; vibroseis; wavelength; zinc; Rocks https://www.scopus.com/inward/record.uri?eid=2-s2.0-84866458793&doi=10.1190%2fgeo2012-0029.1&partnerID=40&md5=5c09d6d532d34310b185d64a6766c86d Cited by: 20 I.T. Kukkonen S. Heinonen P. Heikkinen P. Sorjonen-Ward article Fritz201293 In recent years, deep drilling undertaken as part of the International Continental Drilling Program has generated multiple long lacustrine sedimentary records to reconstruct continental paleoclimate. In many cases, the tectonic and geomorphic history of these basins is under-constrained and poorly known, which affects the interpretation of climate history from geophysical, geochemical, and paleobiotic proxies in the sedimentary record. In addition, non-analog biotic assemblages that reflect evolutionary processes may constrain the reconstruction of past environments. In the drill-core record of Lake Titicaca, spanning the last ~. 370. ka, the diatom stratigraphy reflects both the influence of climate and the long-term evolution of the lake basin and its biota. In the upper part of the drill-core sequence, glacial intervals were deep and dominated by freshwater planktic taxa, and peak interglacial intervals were shallow and dominated by benthic species, some with saline affinities. In the basal sections of the drill-core record, benthic diatoms are dominant in both glacial and interglacial units, with freshwater taxa dominating the glacial strata. This suggests that the ancient lake basin was shallower during intervals of both wet and dry climate, and that the modern deep lake may result from a progressive subsidence and deepening of the basin over time. In addition, morphological evolution in one of the major lineages of planktic diatoms, Cyclostephanos, indicates substantial change in the limnological environment that affected species morphology and may have driven speciation. © 2011 Elsevier B.V. Article 2012 10.1016/j.palaeo.2011.12.013 Palaeogeography, Palaeoclimatology, Palaeoecology 317-318 93 – 103 Andes; Lake Titicaca; Bacillariophyta; Cyclostephanos; deep drilling; diatom; glacial-interglacial cycle; lacustrine deposit; morphology; paleoclimate; paleoecology; paleoenvironment; paleogeography; paleolimnology; plankton; Quaternary; speciation (biology) https://www.scopus.com/inward/record.uri?eid=2-s2.0-84856563699&doi=10.1016%2fj.palaeo.2011.12.013&partnerID=40&md5=fd690b3918b8b019a2312c70123f9582 Cited by: 38; All Open Access, Green Open Access S.C. Fritz P.A. Baker P. Tapia T. Spanbauer K. Westover incollection melezhik2012far 2012 Reading the Archive of Earth’s Oxygenation: Volume 3: Global Events and the Fennoscandian Arctic Russia-Drilling Early Earth Project Springer 1537--1552 Victor A Melezhik AR Prave article Wang201276 The attenuation factor, Q, at a fault zone is an important parameter for understanding the physical properties. In this study, we investigated the Q value of the Chelungpu Fault, the main rupture of the Mw 7.6 Chi-Chi earthquake, using the 7-level TCDP borehole seismometer array (TCDPBHS). The TCDPBHS was deployed at depths from 945 to 1270m throughout the 1999 ruptured slip zone at 1111m. Three borehole seismometers (BHS1-BHS3) were placed in the hanging wall, and the remaining three (BHS5-BHS7) were placed in the foot wall, with BHS4 near the slip zone. The configuration allowed us to estimate the Q-structure of the recent ruptured fault zone. In this study, we estimated Q values between BHS1 and BHS4, Qs 1 (Qp 1) at the fault zone and between BHS4 to 2km in depth, Qs 4 (Qp 4) beneath the fault zone. We utilized two independent methods, the spectral ratio and spectral fitting analyses, for calculating the Q value of Qs 1 (Qp 1) in order to provide a reliability check. After analyzing 26 micro-events for Qs and 17 micro-events for Qp, we obtained consistent Q values from the two independent methods. The values of Qs 1 and Qp 1 were 21-22 and 27-35, respectively. The investigation for the value of Qs 4 was close to 45, and Qp 4 was 85. These Qp and Qs values are quiet consistent with observations obtained for the San Andreas Fault at the corresponding depth. A low Qs 1 value for the recent Chelungpu Fault zone suggests that this fault zone has been highly fractured. Qs values within the Chelungpu Fault, similar to those within the San Andreas Fault, suggest that the Q structure within the fault zone is sedimentary rock independent. However, the possible existence of fluids, fractures, and cracks dominates the attenuation feature in the fault zone. © 2011 Elsevier B.V. 2012 English 00401951 10.1016/j.tecto.2011.12.027 Tectonophysics 578 76-86 Institute of Geophysics, National Central University, Chungli, Taiwan Chelungpu Fault; Drilling projects; Fault-zone attenuation; Qp; Qs; Seismic attenuation, Seismographs; Strike-slip faults, Seismology, borehole; Chi-Chi earthquake 1999; earthquake rupture; fault zone; footwall; San Andreas Fault; sedimentary rock; seismic attenuation; seismograph; slip, Chelungpu Fault Zone; Taiwan https://www.scopus.com/inward/record.uri?eid=2-s2.0-84862166220&doi=10.1016%2fj.tecto.2011.12.027&partnerID=40&md5=840c9e0fc86779d843e12f2b7f0742c5 cited By 11 Y.-J. Wang Y.-Y. Lin M.-C. Lee K.-F. Ma book Li2012107 This chapter presents that highly damaged rocks within the San Andreas fault (SAF) at Parkfield form a low-velocity waveguide to trap seismic waves. The amplitudes and dispersion feature of trapped waves are sensitive to the geometry and physical properties of the fault zone due to the constructive interference conditions of these waves. We use faultzone trapped waves (FZTWs) generated by earthquakes and explosions and recorded at a cross-fault surface array and borehole seismographs at the San Andreas Fault Observatory at Depth (SAFOD) site to document fault zone structure and rock damage at seismogenic depths with high-resolution. Observations and 3-D finite-difference simulations of these FZTWs at dominant frequencies of 2-10 Hz show the downward tapering SAF characterized by a 30-40-m wide fault core with the maximum velocity reduction up to ~50% embedded in a 100-200-m wide zone with velocities reduced by 25%-35% in average from wall-rock velocities. The width and velocity reduction of the damage zone at 3 km depth delineated by FZTWs are verified by the direct measurements in SAFOD drilling and logging studies at this depth [Hickman et al., 2007]. The results indicate that the localization of severe rock damage on the SAF likely reflects pervasive cracking caused by historical earthquakes on it. The magnitude of damage varies with depth and along the fault strike due to rupture distributions and stress variations over multiple length and time scales. The damage is not symmetric across the main slip plane but extends farther on the southwest side of the main fault trace. Based on the depths of earthquakes generating prominent FZTWs, we estimate that the low-velocity damage zone along the SAF at Parkfield extends at least to depths of ~ 7-8 km. © 2012 Higher Education Press and Walter de Gruyter GmbH & Co. KG, Berlin/Boston. 2012 English 9783110259025 10.1515/9783110259032 Imaging, Modeling and Assimilation in Seismology Walter de Gruyter GmbH and Co. KG 107-150 Department of Earth Sciences, University of Southern California, Los Angeles CA 90089, United States; Institute of Earth Science and Engineering, University of Auckland, Auckland 1142, New Zealand; Department of Earth Sciences, University of California-Riverside, Riverside CA 92521, United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-84881753995&doi=10.1515%2f9783110259032&partnerID=40&md5=012294a4feb311d3141791fef6f33a6e cited By 6 Y.-G. Li E.S. Cochran article Poag20121 The Chickahominy Formation is the initial postimpact deposit in the 85km-diameter Chesapeake Bay impact crater, which is centered under the town of Cape Charles, Virginia, USA. The formation comprises dominantly microfossil-rich, silty, marine clay, which accumulated during the final ~1.6myr of late Eocene time. At cored sites, the Chickahominy Formation is 16.8-93.7m thick, and fills a series of small troughs and subbasins, which subdivide the larger Chickahominy basin. Nine coreholes drilled through the Chickahominy Formation (five inside the crater, two near the cratermargin, and two ~3km outside the crater) record the stratigraphic and paleoecologic succession of 301 indigenous species of benthic foraminifera, as well as associated planktonic foraminifera and bolboformids. Two hundred twenty of these benthic species are described herein, and illustrated with scanning electron photomicrographs. The Chickahominy Formation can be categorized as a single benthic foraminiferal biozone (Cibicidoides pippeni Biozone), subdivided into five subzones, in stratigraphic order from bottom to top: Bulimina jacksonensis Subzone; Lagenoglandulina virginiana Subzone; Uvigerina dumblei Subzone; Bolivina tectiformis Subzone, and; Siphonina jacksonensis Subzone. Two planktonic datums and four benthic datums provide a biochronostratigraphic framework in which to estimate the duration and temporal distribution patterns of discrete microfossil assemblages. Apaleoseral succession from pioneer to equilibrium paleocommunities reflects the temporal and spatial evolution from early unstable benthic paleoenvironments to later stable benthic paleoenvironments. Initial reoccupation of the newly formed crater basin is marked by a dramatic immigration of 32 indigenous species, which replaced the sparse, entirely reworked (allochthonous) foraminiferal assemblages of a preceding inhospitable dead zone. At all nine core sites, attainment of benthic paleoenvironmental equilibrium (29-190kyr postimpact) is signaled by a notable reduction in the number of new immigrant species arriving in the Chickahominy basin. In addition, at five sites inside the crater, early unstable benthic paleoenvironments can be differentiated from later stable benthic paleoenvironments by the presence of an agglutinated Psammosiphonella biofacies in basalChickahominy strata and a shift from short-term to long-term benthic foraminiferal generic dominance facies. Restriction of the dead zone and Psammosiphonella biofacies to intracrater sites indicates unusual benthic paleoenvironmental conditions (warm, saline bottomwater and porewater) derived from the impact, which lasted as long as ~350kyr postimpact at one site. Absence of key planktonic foraminiferal and Bolboforma species in early Chickahominy sediments indicates that detrimental effects of the impact also disturbed the upper oceanic water column for at least 80-100kyr postimpact. Nine genera (Bolivina, Uvigerina, Gyroidinoides, Globocassidulina, Angulogerina, Nuttallides, Cibicidina, Caucasina, Epistominella) and two generic groups (buliminids, stilostomellids) are the most abundant taxa among 17 generic dominance facies that characterize Chickahominy core sites. Most dominant taxa were epifaunal or shallow infaunal opportunists, which thrived under conditions of oxygen depletion (dysoxia) and high organic flux rates. After an average of ~73kyr of stressed, rapidly fluctuating paleoenvironments, which were destabilized by after-effects of the impact, most of the cored Chickahominy subbasins maintained stable, nutrient-rich, low-oxygen bottom waters and interstitial microhabitats for the remaining ~1.3myr of late Eocene time. 2012 Micropaleontology 58 1-206 U.S. Geological Survey, 384 Woods Hole Road, Woods Hole, MA 02543-1598, United States 1-2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84864360305&partnerID=40&md5=cc47e77c1eaa28f62a606730ce123227 cited By 4 C.W. Poag article Carpenter2012759 The strength of tectonic faults and the processes that control earthquake rupture remain central questions in fault mechanics and earthquake science. We report on the frictional strength and constitutive properties of intact samples across the main creeping strand of the San Andreas fault (SAF; California, United States) recovered by deep drilling. We find that the fault is extremely weak (friction coefficient, μ = ∼ 0.10), and exhibits both velocity strengthening frictional behavior and anomalously low rates of frictional healing, consistent with aseismic creep. In contrast, wall rock to the northeast shows velocity weakening frictional behavior and positive healing rates, consistent with observed repeating earthquakes on nearby fault strands. We also document a sharp increase in strength to values of μ > ∼0.40 over <1 m distance at the boundary between the fault and adjacent wall rock. The friction values for the SAF are sufficiently low to explain its apparent weakness as inferred from heat flow and stress orientation data. Our results may also indicate that the shear strength of the SAF should remain approximately constant at ∼10 MPa in the upper 5-8 km, rather than increasing linearly with depth, as is commonly assumed. Taken together, our data explain why the main strand of the SAF in central California is weak, extremely localized, and exhibits aseismic creep, while nearby fault strands host repeating earthquakes. © 2012 Geological Society of America. 2012 English 00917613 10.1130/G33007.1 Geology 40 759-762 Department of Geosciences and Energy, Institute Center for Geomechanics, Geofluids, and Geohazards, The Pennsylvania State University, University Park, PA 16802, United States 8 California; Constitutive properties; Deep drilling; Drill core; Earthquake rupture; Fault strands; Friction coefficients; Friction values; Frictional behavior; Frictional properties; Frictional strength; Low rates; Repeating earthquake; San Andreas fault; Sharp increase; Sliding stability; Stress orientations; Tectonic faults, Core drilling; Creep; Earthquakes; Strike-slip faults, Friction, earthquake mechanism; earthquake recurrence; earthquake rupture; fault geometry; friction; rupture; San Andreas Fault; shear strength; slip rate; stability analysis; stress field; tectonic setting; wall rock, California; San Andreas; United States, Calluna vulgaris https://www.scopus.com/inward/record.uri?eid=2-s2.0-84866159192&doi=10.1130%2fG33007.1&partnerID=40&md5=fa0b71405050dbdbf54a37edea2796a9 cited By 82 B.M. Carpenter D.M. Saffer C. Marone article article 2011 10 10.11646/phytotaxa.30.1.1 Phytotaxa 30 1-41 Zlatko Levkov David Williams book kukkonen2011outokumpu 2011 9789522171511 Geological Survey of Finland Geological Survey of Finland https://books.google.de/books?id=gCN6ygAACAAJ I. Kukkonen article Elders2011231 Magma flowed into an exploratory geothermal well at 2.1 km depth being drilled in the Krafla central volcano in Iceland, creating a unique opportunity to study rhyolite magma in situ in a basaltic environment. The quenched magma is a partly vesicular, sparsely phyric, glass containing ~1.8% of dissolved volatiles. Based on calculated H2O-CO2 saturation pressures, it degassed at a pressure intermediate between hydrostatic and lithostatic, and geothermometry indicates that the crystals in the melt formed at ~900 °C. The glass shows no signs of hydrothermal alteration, but its hydrogen and oxygen isotopic ratios are much lower than those of typical mantle-derived magmas, indicating that this rhyolite originated by anhydrous mantle-derived magma assimilating partially melted hydrothermally altered basalts. © 2011 Geological Society of America. 2011 English 00917613 10.1130/G31393.1 Geology 39 231-234 Department of Earth Sciences, University of California-Riverside, Riverside, CA 92521, United States; HS Orka hf, Brekkustigur 36, Reykjanebær IS 260, Iceland; Department of Geology, University of California-Davis, Davis, CA 95616, United States; Department of Geological and Environmental Sciences, Stanford University, Stanford, CA 94305, United States; Iceland GeoSurvey (ÍSOR), Grensásvegur 9, Reykjavik IS 108, Iceland; Landsvirkjun Power, Háaleitisbraut 68, Reykjavik, IS 103, Iceland; U.S. Geological Survey, 345 Middlefield Road, Menlo Park CA 94025, United States; Department of Earth and Environmental Sciences, New Mexico Institute of Mining and Technology, Socorro, NM 87801, United States; Department of Geological Sciences, University of Oregon, Eugene, OR 97403, United States 3 Anhydrous mantle; Geothermometry; Hydrothermal alterations; Hydrothermally; Icelands; In-situ; Oxygen isotopic; Saturation pressure, Geothermal wells; Glass; Granite; Oxygen; Volcanoes, Well drilling, basalt; geothermal system; hydrogen isotope; hydrothermal alteration; magma assimilation; magma chamber; mantle source; oxygen isotope ratio; rhyolite; volcanology, Iceland; Krafla https://www.scopus.com/inward/record.uri?eid=2-s2.0-79951695875&doi=10.1130%2fG31393.1&partnerID=40&md5=e08238af55bd0fc92830d50c59a96bd8 cited By 84 W.A. Elders G.Ó. Fridleifsson R.A. Zierenberg E.C. Pope A.K. Mortensen Á. Gudmundsson J.B. Lowenstern N.E. Marks L. Owens D.K. Bird M. Reed N.J. Olsen P. Schiffman article Kern201183 Laboratory measurements as well as modelling of the physical properties of rock materials are important for the understanding and interpretation of both downhole (logging) and geophysical (surface) observations. On 29 core samples of the Outokumpu scientific drill hole, covering the depth range of 198-2491 m, we calculated the average (isotropic) intrinsic P- and S-wave velocities (V p,Vs) and densities from their modal composition, based on bulk rock (XRF) and mineral chemistry (microprobe), using least squares fitting. For 13 cube-shaped samples representing the main lithologies, we measured P- and S-wave velocities in 3 orthogonal directions at pressures of up to 600 MPa in order to determine their directional dependence and crack sensitivity. Comparison of the calculated velocities with the experimentally derived in situ velocities gave evidence for microcracks that are not completely closed. Microcracks may have an important bearing on the in situ velocities, in addition to the lithological control. Velocity measurements as well as 3D velocity calculations based on neutron diffraction texture measurements revealed that velocity anisotropy and shear wave splitting are important properties of the biotite gneisses that dominate about 70% of the drilled crustal section. Reflection coefficients (Rc) for the various lithological contacts based on modelled and measured velocities provide evidence that the different lithologies of the ophiolite-related assemblage have the potential to cause the marked reflections at 1300-1500 m depth, as revealed by the high-resolution seismic reflection line (OKU-1). Article 2011 English 978-952217152-8 07828535 Special Paper of the Geological Survey of Finland 2011 Kukkonen I.T. 83 – 94 51 Finland; Ita Suomen; Outokumpu; crustal structure; deep drilling; microcrack; ophiolite; P-wave; Proterozoic; S-wave; seismic anisotropy; seismic reflection; seismic wave; wave velocity https://www.scopus.com/inward/record.uri?eid=2-s2.0-80051915214&partnerID=40&md5=570ee1f7d46f5ed2daa5fb8ea09ddc3a Cited by: 6 Hartmut Kern Kurt Mengel article Elbra201195 Longitudinal (VP) and shear wave (Vs) velocities of the upper 1.5 km of the Outokumpu Deep Drill Core were measured using a novel ultrasonic instrument. The aim of the laboratory tests was to determine the seismic velocities of rocks as a function of pressure and temperature and to identify parameters that influence these velocities. The velocities differed significantly throughout the core due to variations in mineralogical composition, lithology, fracturing and anisotropy. Notably, even a minor increase in pressure dramatically increased the VP and VS due to microcrack closure. When the pores and microcracks were closed by pressurization, the highest velocities in the upper schist series (33-1314 m) and the ophiolitic series (1314-1515 m) were met within chlorite-sericite schists (VP 5704 m/s, VS 3495 at 30 MPa) and diopside-tremolite skarns (VP 6572 m/s, VS 3752 m/s at 30 MPa), respectively. This new velocity data could improve the interpretation of crustal models by providing constraints on seismic velocities as well as estimates of the seismic impedances and Poisson's ratios in various rock types in the area of the Outokumpu Deep Drill Core. Article 2011 English 978-952217152-8 07828535 Special Paper of the Geological Survey of Finland 2011 Kukkonen I.T. 95 – 104 51 Finland; Ita Suomen; Outokumpu; crustal structure; deep drilling; metasedimentary rock; P-wave; Proterozoic; S-wave; seismic velocity; seismic wave; wave velocity https://www.scopus.com/inward/record.uri?eid=2-s2.0-80051860763&partnerID=40&md5=c9bc180a991c106742433f339f8ae9e4 Cited by: 2 Tiiu Elbra Ronnie Karlqvist Ilkka Lassila Edward Hæggström Lauri J. Pesonen article Velasco-Villareal2011154 Results of a paleomagnetic study of 89 samples from impact breccias from the Chicxulub crater are presented and used to investigate on ejecta emplacement, hydrothermal and alteration processes. The impactite sequence sampled in cores from Yaxcopoil-1 borehole is ∼100. m thick and formed by six subunits characterized by petrographic, scan images, geochemical and textural analyses, which point to different emplacement modes. Impact occurred within reverse polarity chron C29r; therefore, magnetization acquired at crater formation and shortly thereafter will present reverse polarity, which is supported by paleomagnetic measurements on melt samples from Yucatan-6 borehole. Results after step-wise thermal and alternating field demagnetization document a pattern of 23 upward and 29 downward inclinations at Yaxcopoil-1 around -33° and 38°, respectively. Measurements of magnetic hysteresis and variation of low-field susceptibility with temperature suggest low-Ti titanomagnetites and magnetite as main magnetic carriers. Petrographic observations indicate the presence of fine-grained magnetite, hematite and Fe-oxyhydroxides, related to hydrothermal alteration processes. Curie points are in the range of 520-580 °C. The wide range of unblocking temperature spectra points to variable grain sizes of a magnetic phase that unblocks around 580 °C. Hysteresis ratio plots indicate most samples fall in the pseudo-single domain field. In some samples, wasp-waist constrained hysteresis loops suggest magnetite and hematite. Analyses of vector plots and coercivity and unblocking temperature spectra do not show apparent differences within and between subunits. Subunits are characterized by distinct textural and compositional differences in size, type and relative abundance of clasts and melt-rich or carbonate-rich matrix types. Bulk properties vary with composition and clast contents, particularly within the Middle Suevite and Brecciated Melt Rock subunits that show higher values, while low values characterize the Lower Suevite carbonate-rich with rare basement clasts subunit. Magnetization acquisition mechanisms are discussed, with reference to impactite characteristics, and may relate to remagnetization from hydrothermal and post-impact alteration processes. © 2011 Elsevier B.V. 2011 10.1016/j.pepi.2011.04.003 Physics of the Earth and Planetary Interiors 186 154-171 Proyecto Universitario de Perforaciones en Océanos y Continentes, Instituto de Geofísica, Universidad Nacional Autónoma de México, Coyoacan, 04510 México D.F., Mexico; Unidad de Ciencias del Agua, Centro de Investigación Científica de Yucatán (CICY), Mérida, Yucatán, Mexico 3-4 https://www.scopus.com/inward/record.uri?eid=2-s2.0-79957847736&doi=10.1016%2fj.pepi.2011.04.003&partnerID=40&md5=773af3c3404c6acc798787e3cf95f919 cited By 9 M. Velasco-Villareal J. Urrutia-Fucugauchi M. Rebolledo-Vieyra L. Pérez-Cruz article Wang20111411 A group of methyltrimethyltridecyl chromans (MTTCs) was found in core samples of Member 1 (K2n1) and Member 2 (K2n2) of the Nenjiang Formation (Upper Cretaceous) from the SK-l southern borehole (Songliao Basin, China). They are assigned for the first time in sediments older than the Tertiary in China. Their composition and distribution are indicative mainly of the redox and salinity conditions in the depositional environment. The δ-MTTC isomer is in relatively higher abundance in samples from enhanced salinity and reducing conditions, but was not detected in samples from aerobic and low salinity environments, while α-MTTC appears to be present in samples from environments with a broad range of salinity and redox conditions. The α-MTTC/γ-MTTC (α/γ) ratio has a similar indication as that of the α/δ ratio and could be used as a corroborative ratio of paleosalinity. A combination of biomarker parameters suggests that the massive lacustrine petroleum-prone source rocks associated with the K2n1 interval were likely developed under a stratified water column with enhanced salinity and an anoxic bottom water layer, associated with a much less saline (fresh to brackish) upper water layer. © 2011 Elsevier Ltd. 2011 English 01466380 10.1016/j.orggeochem.2011.08.012 Organic Geochemistry 42 1411-1419 State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; Department of Earth and Planetary Sciences, Macquarie University, NSW 2109, Australia; Graduate School of Chinese Academy of Sciences, Beijing 100039, China 11 Bottom water; Depositional environment; Low salinity; Occurrence and distribution; Redox condition; Reducing conditions; Songliao basin; Source rocks; Stratified waters; Upper Cretaceous; Water layers, Anoxic sediments; Saline water, Salinity measurement, biomarker; borehole; Cretaceous; depositional environment; lacustrine deposit; paleosalinity; redox conditions; relative abundance; sampling; source rock; Tertiary; water column, China; Songliao Basin https://www.scopus.com/inward/record.uri?eid=2-s2.0-80855139639&doi=10.1016%2fj.orggeochem.2011.08.012&partnerID=40&md5=86a94d9612ba1607d3987d73f5d9aa4c cited By 53 L. Wang Z. Song Q. Yin S.C. George article Västi201117 Deep reflection seismic measurements in 2002 across the Outokumpu region revealed numerous reflectors, some of which related to mafic rock assemblages or to rocks that otherwise showed impedance contrasts with their surroundings. Two shallow reflective zones were later targeted for drilling in order to test interpretations of the seismic data. The immediate proximity of the famous Outokumpu ore belt naturally provided an additional incentive for drilling, which was undertaken by NEDRA, a state owned Russian drilling contractor. The Outokumpu region is located within the Paleoproterozoic Karelian schist belt close to the boundary between the Neoarchaean craton in the east and the Paleoproterozoic Svecofennian island arc complex in the west. The Karelian schist belt is divided into the lower Sariolan and Jatulian (2.5-2.1 Ga, mainly autochthonous), and the upper Kalevian (2.1-1.9 Ga) units. The deep drill hole R2500 is located in the allochthonous upper part of the latter unit. The uppermost 2 km of the drill hole consists mainly of mica schist with minor biotite gneiss, chlorite-sericite schist, black schist and hornblende-epidote schist intercalations. Within the interval ca. 1300-1500 m, the mica schist formation encloses a previously unknown assemblage of Outokumpu-type rocks. From ca. 1650 m downwards mica schist is intruded by pegmatitic granitoids, which in turn dominate from ca. 2000 m downwards. The chemical index of alteration (CIA) of the mica schists and biotite gneisses (50.3-65.2) indicates weak to moderate weathering of their source rocks. The lower CIA values of the mica schists probably reflect rapid and subsequent erosion, transportation and re-deposition from large deltas. On the other hand the higher CIA value of the biotite gneisses is a consequence of mineralogy, because it was originally fine-grained shale rich in clay minerals. Chlorite-sericite schist closely resembles mica schist chemically, while the hornblende-epidote schist differs in containing distinctly more CaO and less Na2O and K2O. Black schists are divided into two main types: "ordinary" black schist and calcareous black schist. The latter type is rich in tremolite and differs chemically mainly in containing less SiO2 and more CaO and MgO. Rocks of the Outokumpu assemblage consist of lithologically diverse rock types ranging from monomineralic serpentinites to various diopside- and/or tremolite-bearing skarns and quartz rocks. A few narrow and strongly schistose mafic dykes, which have been altered to chlorite schists, crosscut skarn. Primarily the Outokumpu-type rock assemblages represent fragments of mantle peridotites affected by hydrothermal and metasomatic alteration. For this reason serpentinites, skarns and quartz rocks usually have trace element concentrations very similar to pyrolite. Although pegmatitic granitoids show significant variations in the modal composition, they are always very leucocratic (M=0.2-4). Chemically all pegmatite types display peraluminous affinities (A/CNK = 1.02-2.08). On A/CNK versus SiO2 and Na 2O versus K2O diagrams pegmatites fall into both S-type or I-type categories. Article 2011 English 978-952217152-8 07828535 Special Paper of the Geological Survey of Finland 2011 Kukkonen I.T. 17 – 46 51 Finland; Ita Suomen; Outokumpu; Archean; biotite; craton; deep drilling; gneiss; granitoid; metasedimentary rock; mica; mineralogy; pegmatite; petrology; Proterozoic; schist; seismic data; seismic reflection; serpentinite; skarn https://www.scopus.com/inward/record.uri?eid=2-s2.0-80051871690&partnerID=40&md5=89c43fa5c805254bfe8f7ca60aeddbcc Cited by: 11 Kaj Västi article Gogorza201141 High-resolution paleo- and rock magnetic studies were performed on a group of four sediment cores from Laguna Potrok Aike (Santa Cruz, Argentina) representing the time period AD 1300-2000. The rock magnetic analyses show that the main magnetic mineral is (titano)magnetite with a concentration between 0.01 and 0.08%, and a grain size of 4-15 μm. This study is helpful in order to complete the paleosecular variation (PSV) and paleointensity type curves for South America which do not have a detailed record for the last millennium. The comparison with the study carried out for Lake El Trébol shows a very good agreement, supporting that PSV records of south-western Argentina can be developed into a stratigraphic correlation tool on a regional scale. © 2010 Elsevier B.V. Article 2011 10.1016/j.pepi.2010.10.011 Physics of the Earth and Planetary Interiors 184 41 – 50 1-2 Argentina; Laguna Potrok Aike; Santa Cruz [Argentina]; Iron ores; Lithology; Stratigraphy; ICDP; Paleointensity; Paleosecular variations; PASADO; Southern Hemisphere; core analysis; geochronology; Holocene; magnetic intensity; magnetic survey; paleomagnetism; secular variation; sediment core; Southern Hemisphere; stratigraphic correlation; Minerals https://www.scopus.com/inward/record.uri?eid=2-s2.0-78651472900&doi=10.1016%2fj.pepi.2010.10.011&partnerID=40&md5=b001a09c839264ce3251d0f76634e59d Cited by: 16 C.S.G. Gogorza A.M. Sinito C. Ohlendorf S. Kastner B. Zolitschka article Li20111 Two boreholes drilled approximately 75 km apart in the Songliao Basin, Northeast China, have together provided a composite core that represents an almost continuous section through Late Cretaceous-early Paleocene deposits. Eight biozones have been established for this succession of seven formations based on occurrences and associations of biostratigraphically significant palynomorph genera. Seven of these suggest that there was more or less continuous deposition from the late Turonian to the early Paleocene, with the eighth encompassing a Miocene formation that overlies the succession unconformably. This zonation provides a new chronostratigraphic framework for the Late Cretaceous deposits of the Songliao Basin. The ages of most of the formations involved differ from those determined previously. One of the sedimentary units, the Mingshui Formation, includes the Cretaceous/Paleogene boundary, which seems to be indicated by an apparent " mass extinction" of palynomorph taxa, a comparatively rare occurrence outside North America. The upper Quantou Formation, the lowest unit in the succession, is dated as late Turonian-Coniacian, which is much younger than previously thought. The same applies to the overlying Qingshankou and Yaojia formations, and also to the other three (Nenjiang, Sifangtai and Mingshui) but to a lesser extent, in the conformable succession. The Early/Late Cretaceous boundary must now be located probably below the Quantou Formation, either between it and the underlying Denglouku Formation or within the latter. © 2010 Elsevier Ltd. 2011 English 01956671 10.1016/j.cretres.2010.09.001 Cretaceous Research 32 1-12 State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, CAS, 39 East Beijing Road, 210008, Nanjing, China; School of Earth, Atmospheric and Environmental Earth Sciences, University of Manchester, Oxford Road, Manchester, M13 9PL, United Kingdom; Institute of Geography and Earth Sciences, Aberystwyth University, Penglais, Aberystwyth SY23 3DB, Wales, United Kingdom 1 biostratigraphy; biozonation; chronostratigraphy; Cretaceous; Paleocene; palynology; palynomorph; taxonomy; Tertiary, China; Songliao Basin, Coniacian https://www.scopus.com/inward/record.uri?eid=2-s2.0-78649821758&doi=10.1016%2fj.cretres.2010.09.001&partnerID=40&md5=865885e89cf5f5defb06a5697599badf cited By 43 J. Li D.J. Batten Y. Zhang article Potanina2011610 Based on the data of the detailed earthquake catalog provided on the website of the Corinth Rift Laboratory, zones of swarm activity are revealed and the variations in the statistical parameters of seismic swarms that occurred in the western part of the Gulf of Corinth are calculated. The preliminary analysis of the catalogue is carried out; the magnitude of completeness and the accuracy of the location of the earth-quake are estimated; the changes in these parameters associated with the development of the observational network are assessed. The b-value (b-values) and the cluster dimension of the set of hypocenters are estimated, and time variations in these parameters in the course of the evolution of swarm activity are revealed. The style of changes in the parameters characterizing the seismic regime during intervals of swarm activity indicates that the process of failure exhibits scale redistribution over the course of time, changing from upscaling (progression from smaller to larger scales) at the stage of increasing seismicity to downscaling (progression from larger to lower scales) at the stage of decay. These particular features of enhancement and reduction of swarm seismicity are qualitatively similar to the scenarios of source preparation and aftershock relaxation of strong earthquakes. The pattern of variations of the swarm seismicity studied is similar to those identified in the previous laboratory and field modeling of various transient modes of seismicity. This fact confirms the relevancy of the retrieved results and conclusions based on the laboratory studies of transient modes, and suggests that the latter have a universal governing mechanism. © 2011 Pleiades Publishing, Ltd. Article 2011 English 10693513 10.1134/S106935131106005X Izvestiya, Physics of the Solid Earth 47 610 – 622 7 https://www.scopus.com/inward/record.uri?eid=2-s2.0-79960157329&doi=10.1134%2fS106935131106005X&partnerID=40&md5=597a794c3e017d7da0762373b520cccb Cited by: 6 M.G. Potanina V.B. Smirnov P. Bernard article Collett2011279 In the 1960s Russian scientists made what was then a bold assertion that gas hydrates should occur in abundance in nature. Since this early start, the scientific foundation has been built for the realization that gas hydrates are a global phenomenon, occurring in permafrost regions of the arctic and in deep water portions of most continental margins worldwide. In 1995, the U.S. Geological Survey made the first systematic assessment of the in-place natural gas hydrate resources of the United States. That study suggested that the amount of gas in the gas hydrate accumulations of northern Alaska probably exceeds the volume of known conventional gas resources on the North Slope. Researchers have long speculated that gas hydrates could eventually become a producible energy resource, yet technical and economic hurdles have historically made gas hydrate development a distant goal. This view began to change in recent years with the realization that this unconventional resource could be developed with existing conventional oil and gas production technology. One of the most significant developments was the completion of the BPXA-DOE-USGS Mount Elbert Gas Hydrate Stratigraphic Test Well on the Alaska North Slope, which along with the Mallik project in Canada, have for the first time allowed the rational assessment of gas hydrate production technology and concepts. Almost 40 years of gas hydrate research in northern Alaska has confirmed the occurrence of at least two large gas hydrate accumulations on the North Slope. We have also seen in Alaska the first ever assessment of how much gas could be technically recovered from gas hydrates. However, significant technical concerns need to be further resolved in order to assess the ultimate impact of gas hydrate energy resource development in northern Alaska. © 2009 Elsevier Ltd. 2011 English 02648172 10.1016/j.marpetgeo.2009.12.001 Marine and Petroleum Geology 28 279-294 Energy Resources Program, U.S. Geological Survey, Denver Federal Center, MS-939, Box 25046, Denver, CO 80225, United States; U.S. Department of Energy, National Energy Technology Laboratory, Morgantown, WV 26507, United States; IS Interpretation Services, Inc., 1600 Stout Street, Suite 1520, Denver, CO 80202, United States 2 Alaska; Coring; Exploration; Petroleum systems; Resources; Seismic analysis, Energy resources; Gases; Hydration; Natural gas; Natural gas deposits; Natural gas well completion; Natural gas well drilling; Offshore oil wells; Permafrost; Petroleum deposits; Petroleum prospecting; Production; Rating; Resource valuation; Seismology; Stratigraphy, Gas hydrates, core logging; drilling; gas hydrate; gas production; hydrocarbon exploration; hydrocarbon generation; hydrocarbon resource; hydrocarbon technology; natural gas; permafrost, Alaska; North Slope; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-78651429017&doi=10.1016%2fj.marpetgeo.2009.12.001&partnerID=40&md5=50ee82dfb29131376801d1df02d7c6da cited By 192 T.S. Collett M.W. Lee W.F. Agena J.J. Miller K.A. Lewis M.V. Zyrianova R. Boswell T.L. Inks article Elbra20111640 The Chicxulub structure in Mexico, one of the largest impact structures on Earth, was formed 65Ma by a hypervelocity impact that led to the large mass extinction at the K-Pg boundary. The Chicxulub impact structure is well preserved, but is buried beneath a sequence of carbonate sediments and, thus, requires drilling to obtain subsurface information. The Chicxulub Scientific Drilling Program was carried out at Hacienda Yaxcopoil in the framework of the International Continental Scientific Drilling Program in 2001-2002. The structure was cored from 404m down to 1511m, through three intervals: 794m of postimpact Tertiary sediments, a 100m thick impactite sequence, and 616m of preimpact Cretaceous rocks thought to represent a suite of megablocks. Physical property investigations show that the various lithologies, including the impactite units and the K-Pg boundary layer, can be characterized by their physical properties, which depend on either changes in fabric or on mineralogical variations. The magnetic properties show mostly dia- or paramagnetic behavior, with the exception of the impactite units that indicate the presence of ferromagnetic, probably hydrothermally deposited magnetite and pyrrhotite. The magnetic fraction contributes mainly to enhanced magnetization in the impactite lithologies and, in this way, to the observed magnetic anomalies. The shape and orientation of the magnetic grains are varied and reflect inhomogeneous fabric development and the influence of impact-related redeposition and hydrothermal activity. The Chicxulub impact occurred at the time of the reverse polarity geomagnetic chron 29R, and this finding is consistent with the age of the K-Pg boundary. © The Meteoritical Society, 2011. 2011 10.1111/j.1945-5100.2011.01253.x Meteoritics and Planetary Science 46 1640-1652 Division of Geophysics and Astronomy, Department of Physics, 00014 University of Helsinki, P.O. Box 64, Helsinki, Finland 11 https://www.scopus.com/inward/record.uri?eid=2-s2.0-80155180620&doi=10.1111%2fj.1945-5100.2011.01253.x&partnerID=40&md5=2524f21eaf8e7f86f515756d4d9940d2 cited By 13 T. Elbra L.J. Pesonen article Castañeda2011140 Relatively few well-dated and high-resolution paleoclimate records of the past few centuries presently exist from tropical East Africa. Here, we examine the bulk and molecular geochemical records of two varved sediment cores from Lake Malawi, which together provide a continuous record of environmental variability in East Africa of the last 730years. We observe a number of changes in the aquatic ecosystem of Lake Malawi, which are likely attributed to both natural climatic forcing and anthropogenic activities. Biomarkers of dinoflagellates (dinosterol) and bacterivorous ciliates (tetrahymanol) display increased accumulation rates from ~1900AD to the present, while a simultaneous decrease in accumulation rates of diatom biomarkers (isololiolide/loliolide) is observed. Increased accumulation rates of retene, a compound derived from conifers, are also noted since ~1930AD and likely reflect increased soil erosion due to deforestation of the Lake Malawi watershed. Spectral analysis of the high-resolution TOC record indicates a periodicity of 204years, similar to the 206year cycle noted in 14C and 10Be records, suggesting a link between East African climate and solar forcing. © 2010 Elsevier B.V. 2011 English 00310182 10.1016/j.palaeo.2010.01.006 Palaeogeography, Palaeoclimatology, Palaeoecology 303 140-154 Large Lakes Observatory, University of Minnesota Duluth, 2205 E. 5th St., Duluth, MN 55812, United States; Department of Geology and Geophysics, University of Minnesota, 310 Pillsbury Drive SE, Minneapolis, MN 55455, United States; Department of Geological Sciences, University of Minnesota Duluth, 1114 Kirby Drive, Duluth, MN 55812, United States; Department of Chemistry and Biochemistry, University of Minnesota Duluth, 1039 University Drive, Duluth, MN 55812, United States 1-4 accumulation rate; biomarker; ciliate; climate variation; deforestation; dinoflagellate; geochemical method; paleoclimate; phytoplankton; primary production; proxy climate record; sediment core; soil erosion; spectral analysis; tropical region, East Africa; East African Lakes; Lake Malawi, Bacillariophyta; Ciliophora; Coniferophyta; Dinophyceae https://www.scopus.com/inward/record.uri?eid=2-s2.0-79953161076&doi=10.1016%2fj.palaeo.2010.01.006&partnerID=40&md5=12e53126aea4b486743132f69a9debf6 cited By 42 I.S. Castañeda J.P. Werne T.C. Johnson L.A. Powers article Airo201163 Petrophysical laboratory measurements of the Outokumpu Deep Drill Core were carried out in 2005-2008 at the Geophysical Laboratory of the Geological Survey of Finland (GTK). This report describes the pre-processing and measurement procedures and summarizes the measurement results of a total of 1992 samples taken at one-metre intervals along the drill core, representing depths from 55.5 m to 2503.9 m. The determined parameters were density and porosity, magnetic susceptibility and the intensity of remanent magnetization, electrical properties (resistivity and chargeability), P-wave velocity and thermal conductivity. The samples represented different rock types, and their petrophysical parameters showed typical values reflecting the mineralogical variation in the rocks. Generally weak magnetic properties characterize both the drill core samples and the outcropping bedrock (magnetic susceptibilities mainly ≤ 1000 × 10-6 SI). The only magnetically anomalous rocks are serpentinites and other altered ophiolitederived rocks of the Outokumpu assemblage, with susceptibilities of the order of ≥ 10 000 × 10-6 SI. No clear systematic effect of depth along the drill core on density or susceptibility can be observed. P-wave velocity and specific resistivity tend to decrease with depth. The porosity of mica schists increases with depth, but the drill core bulk densities do not change. Microfracturing due to pressure release possibly explains part of this effect. However, the grain densities of mica schists tend to increase with depth. Compared with surface densities, the densities of different rock types in the core are ca. 40 kg/m3 higher than the densities of corresponding rock types exposed around the drilling site (< 100 km). The magnetic properties of different rock types are of about the same intensity. Only black schists on the surface are more highly magnetic than those from the core, suggesting differences in monoclinic / hexagonal pyrrhotite contents. Article 2011 English 978-952217152-8 07828535 Special Paper of the Geological Survey of Finland 2011 Kukkonen I.T. 63 – 82 51 Finland; Ita Suomen; Outokumpu; bedrock; deep drilling; density; electrical property; magnetic susceptibility; metamorphic rock; mica; outcrop; physical property; porosity; remanent magnetization https://www.scopus.com/inward/record.uri?eid=2-s2.0-80051881757&partnerID=40&md5=ba03b74e950d423732997ac2c129a3b7 Cited by: 8 Meri-Liisa Airo Heikki Säävuori Satu Vuoriainen article Powers2011133 We have applied the TEX86 paleothermometer to produce a surface water temperature record for Lake Malawi spanning the past 700years. Over much of the record temperature fluctuates from ~24-27°C with a mean of ~25°C; however, there has been a substantial increase in temperature of ~2.0°C during the past ~ 100years. The TEX86 temperature record reveals a strong similarity to the instrumental record; both records demonstrate warming (~0.7-1.4°C) over the past ~50years as well as a cooling anomaly around 1959. Comparison of the TEX86 temperature record with the proxy records of primary productivity suggests that wind induced upwelling and/or precipitation have a strong influence on the surface temperature of Lake Malawi. © 2010 Elsevier B.V. 2011 English 00310182 10.1016/j.palaeo.2010.09.006 Palaeogeography, Palaeoclimatology, Palaeoecology 303 133-139 Large Lakes Observatory, University of Minnesota Duluth, 10 University Dr., Duluth, MN 55812, United States; Department of Geological Sciences, University of Minnesota Duluth, 1114 Kirby Dr., Duluth, MN 55812, United States; Department of Chemistry and Biochemistry, University of Minnesota Duluth, 1039 University Dr., Duluth, MN 55812, United States; NIOZ, Royal Netherlands Institute for Sea Research, Department of Marine Organic Biogeochemistry, PO Box 59, 1790 Den Burg, Texel, Netherlands; Department of Geosciences, University of Utrecht, Utrecht, Netherlands 1-4 geochemical method; paleoclimate; paleotemperature; primary production; prokaryote; proxy climate record; surface temperature; surface water; water temperature, East African Lakes; Lake Malawi, Archaea https://www.scopus.com/inward/record.uri?eid=2-s2.0-79953162990&doi=10.1016%2fj.palaeo.2010.09.006&partnerID=40&md5=e24034ca360f8adc75a21343276c6573 cited By 37 L.A. Powers T.C. Johnson J.P. Werne I.S. Castañeda E.C. Hopmans J.S. Sinninghe Damsté S. Schouten article Bartosova2011396 The center of the 35.3Ma Chesapeake Bay impact structure (85km diameter) was drilled during 2005/2006 in an ICDP-USGS drilling project. The Eyreville drill cores include polymict impact breccias and associated rocks (1397-1551m depth). Tens of melt particles from these impactites were studied by optical and electron microscopy, electron microprobe, and microRaman spectroscopy, and classified into six groups: m1-clear or brownish melt, m2-brownish melt altered to phyllosilicates, m3-colorless silica melt, m4-melt with pyroxene and plagioclase crystallites, m5-dark brown melt, and m6-melt with globular texture. These melt types have partly overlapping major element abundances, and large compositional variations due to the presence of schlieren, poorly mixed melt phases, partly digested clasts, and variable crystallization and alteration. The different melt types also vary in their abundance with depth in the drill core. Based on the chemical data, mixing calculations were performed to determine possible precursors of these melt particles. The calculations suggest that most melt types formed mainly from the thick sedimentary section of the target sequence (mainly the Potomac Formation), but an additional crystalline basement (schist/gneiss) precursor is likely for the most abundant melt types m2 and m5. Sedimentary rocks with compositions similar to those of the melt particles are present among the Eyreville core samples. Therefore, sedimentary target rocks were the main precursor of the Eyreville melt particles. However, the composition of the melt particles is not only the result of the precursor composition but also the result of changes during melting and solidification, as well as postimpact alteration, which must also be considered. The variability of the melt particle compositions reflects the variety of target rocks and indicates that there was no uniform melt source. Original heterogeneities, resulting from melting of different target rocks, may be preserved in impactites of some large impact structures that formed in volatile-rich targets, because no large melt body exists, in which homogenization would have taken place. © The Meteoritical Society, 2011. 2011 10.1111/j.1945-5100.2011.01162.x Meteoritics and Planetary Science 46 396-430 Department of Lithospheric Research, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria; Museum für Naturkunde, Leibniz-Institute at Humboldt University Berlin, Invalidenstrasse 43, 10115 Berlin, Germany; Natural History Museum, Burgring 7, A-1010 Vienna, Austria; Institute of Mineralogy and Crystallography, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria 3 https://www.scopus.com/inward/record.uri?eid=2-s2.0-79952727590&doi=10.1111%2fj.1945-5100.2011.01162.x&partnerID=40&md5=ae9a6c7aed42d58457019f9684b35feb cited By 3 K. Bartosova L. Hecht C. Koeberl E. Libowitzky W.U. Reimold article qinghong2011optimum 2011 Coal Geology & Exploration 39 71-73 1 MENG Qinghong Zhang Hengchun HU Yule others article Brigham-Grette201180 2011 English 10428275 10.5670/oceanog.2011.58 Oceanography 24 80-81 Department of Geosciences, University of Massachusetts, Amherst, MA, United States; Institute of Geology and Mineralogy, University of Cologne, Cologne, Germany; North-East Interdisciplinary Scientific Research Institute, Magadan, Russian Federation; Department of Lithospheric Research, University of Vienna, Natural History Museum of Vienna, Vienna, Austria 3 https://www.scopus.com/inward/record.uri?eid=2-s2.0-80052571001&doi=10.5670%2foceanog.2011.58&partnerID=40&md5=ba58c80e8c004674bc7254c3b323ae2e cited By 0 J. Brigham-Grette M. Melles P. Minyuk C. Koeberl article Wagner2011995 Review 2011 English 17264189 10.5194/bg-8-995-2011 Biogeosciences 8 995 – 998 4 Balkans; Lake Mikri Prespa; Lake Ohrid; geomorphological mapping; historical record; history of geology; lake evolution https://www.scopus.com/inward/record.uri?eid=2-s2.0-79955380917&doi=10.5194%2fbg-8-995-2011&partnerID=40&md5=1205da676e3a894dc6e3bbb2e89014bf Cited by: 22; All Open Access, Gold Open Access, Green Open Access B. Wagner T. Wilke article McHargue2011110 The cosmogenic radionuclide 10Be was measured from drill core sediments from Lake Malawi in order to help construct a chronology for the study of the tropical paleoclimate in East Africa. Sediment samples were taken every 10m from the core MAL05-1C to 80m in depth and then from that depth in core MAL05-1B to 382m. Sediment samples were then later taken at a higher resolution of every 2m from MAL05-1C. They were then leached to remove the authigenic fraction, the leachate was processed to separate out the beryllium isotopes, and 10Be was measured at the TAMS Facility at the University of Arizona. The 10Be/9Be profile from Lake Malawi sediments is similar to those derived from marine sediment cores for the late Pleistocene, and is consistent with the few radiocarbon and OSL IR measurements made from the same core. Nevertheless, a strong correlation between the stable isotope 9Be and the cosmogenic isotope 10Be suggests that both isotopes have been well mixed before deposition unlike in some marine sediment cores. In addition, the correlation of beryllium isotopes to a proxy of lake level TOC (Total Organic Matter) from Lake Malawi indicates that the concentrations of 10Be in the lake sediments result from the combined effects of global and local climates on lake level, local hydrology, and sediment transport in the Lake Malawi basin rather than as a direct response to its production in the atmosphere modulated by the intensity of the Earth's dipole. Therefore, a direct correlation of the 10Be/9Be to a chronology derived from the paleomagnetic variations measured from marine sediments was not possible. Nevertheless, a comparison of the 10Be/9Be chronology, allowing for decay, at Lake Malawi to that of the global marine paleomagnetic record suggests that the bottom of core MAL05-1B is no more than 750ka in age. © 2010. 2011 English 00310182 10.1016/j.palaeo.2010.02.012 Palaeogeography, Palaeoclimatology, Palaeoecology 303 110-119 Department of Geosciences, University of Arizona, 1040 E. Fourth Street, Tucson, AZ 85721, United States; NSF Arizona AMS Laboratory, University of Arizona, 1118 E. Fourth Street, Tucson, AZ 85721, United States 1-4 beryllium isotope; cosmogenic radionuclide; geochronology; lacustrine deposit; lake level; marine record; marine sediment; paleoclimate; paleomagnetism; radiocarbon dating; sediment core; sediment transport, East Africa; East African Lakes; Lake Malawi https://www.scopus.com/inward/record.uri?eid=2-s2.0-79953162198&doi=10.1016%2fj.palaeo.2010.02.012&partnerID=40&md5=4e48d675f841125de47e5f887e6447e3 cited By 10 L.R. McHargue A.J.T. Jull A. Cohen article Wenk201169 Increasing use of diffraction methods to study preferred orientation of minerals has established that quartz in deformed rocks not only displays characteristic c-axis orientation patterns, but that there is also generally a distinct difference in the orientation of positive and negative rhombs. In the trigonal quartz crystal structure positive and negative rhombs are structurally different, and particularly negative rhombs (e.g. {01. 1-1}) are much stiffer than positive rhombs (e.g. {10. 1-1}). Here, we focus on the role of mechanical Dauphiné twinning under stress as a cause of this difference and illustrate with EBSD measurements ubiquitous twinning in quartz-bearing rocks subjected to high stresses. Characteristic twinning is observed in experimentally shocked sandstones and stishovite-bearing quartzites from the Vredefort meteorite impact site in South Africa. Similar twinning is documented for quartz associated with pseudotachylites from the Santa Rosa mylonite zone in Southern California, whereas quartz in underlying ductile mylonites are more or less twin-free. It suggests that twinning was produced by local seismic stresses that caused fracture and frictional melting on fault surfaces. Quartz-bearing breccias from the SAFOD (San Andreas Fault Observatory at Depth) drilling project also show evidence of twinning and suggest high seismic stresses in the currently creeping segment of the San Andreas Fault at Parkfield. From these observations it appears that Dauphiné twin microstructures can be diagnostic of high local and transient stresses. © 2011 Elsevier B.V. 2011 English 00401951 10.1016/j.tecto.2011.06.016 Tectonophysics 510 69-79 Department of Earth and Planetary Science, University of California, Berkeley, CA 94720, United States; GFZ German Research Centre for Geosciences, Telegrafenberg, 14473 Potsdam, Germany; Institut für Geowissenschaften, Geologie, Albert-Ludwigs-Universität, 79085 Freiburg, Germany 1-2 C-axis orientations; Creeping segment; Diffraction methods; Drilling projects; EBSD; Fault breccia; Fault surfaces; Frictional melting; High stress; Mechanical twinning; Meteorite impact; Mylonites; Preferred orientations; Pseudotachylites; San Andreas Fault; Seismic stress; Shock deformation; South Africa; Southern California; Transient stress; Twin-free, Crystal structure; Meteor impacts; Quartz deposits; Rocks; Seismology; Structural geology, Quartz, breccia; crystal structure; deformation mechanism; ductile deformation; experimental study; microstructure; preferred orientation; pseudotachylite; quartz; San Andreas Fault; twinning, South Africa https://www.scopus.com/inward/record.uri?eid=2-s2.0-80052732693&doi=10.1016%2fj.tecto.2011.06.016&partnerID=40&md5=e158acb0dcf8244b34cd65f3c37e4e17 cited By 35 H.-R. Wenk C. Janssen T. Kenkmann G. Dresen article Bartosova2011396 The center of the 35.3Ma Chesapeake Bay impact structure (85km diameter) was drilled during 2005/2006 in an ICDP-USGS drilling project. The Eyreville drill cores include polymict impact breccias and associated rocks (1397-1551m depth). Tens of melt particles from these impactites were studied by optical and electron microscopy, electron microprobe, and microRaman spectroscopy, and classified into six groups: m1-clear or brownish melt, m2-brownish melt altered to phyllosilicates, m3-colorless silica melt, m4-melt with pyroxene and plagioclase crystallites, m5-dark brown melt, and m6-melt with globular texture. These melt types have partly overlapping major element abundances, and large compositional variations due to the presence of schlieren, poorly mixed melt phases, partly digested clasts, and variable crystallization and alteration. The different melt types also vary in their abundance with depth in the drill core. Based on the chemical data, mixing calculations were performed to determine possible precursors of these melt particles. The calculations suggest that most melt types formed mainly from the thick sedimentary section of the target sequence (mainly the Potomac Formation), but an additional crystalline basement (schist/gneiss) precursor is likely for the most abundant melt types m2 and m5. Sedimentary rocks with compositions similar to those of the melt particles are present among the Eyreville core samples. Therefore, sedimentary target rocks were the main precursor of the Eyreville melt particles. However, the composition of the melt particles is not only the result of the precursor composition but also the result of changes during melting and solidification, as well as postimpact alteration, which must also be considered. The variability of the melt particle compositions reflects the variety of target rocks and indicates that there was no uniform melt source. Original heterogeneities, resulting from melting of different target rocks, may be preserved in impactites of some large impact structures that formed in volatile-rich targets, because no large melt body exists, in which homogenization would have taken place. © The Meteoritical Society, 2011. 2011 English 10869379 10.1111/j.1945-5100.2011.01162.x Meteoritics and Planetary Science 46 396-430 Department of Lithospheric Research, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria; Museum für Naturkunde, Leibniz-Institute at Humboldt University Berlin, Invalidenstrasse 43, 10115 Berlin, Germany; Natural History Museum, Burgring 7, A-1010 Vienna, Austria; Institute of Mineralogy and Crystallography, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria 3 https://www.scopus.com/inward/record.uri?eid=2-s2.0-79952727590&doi=10.1111%2fj.1945-5100.2011.01162.x&partnerID=40&md5=ae9a6c7aed42d58457019f9684b35feb cited By 3 K. Bartosova L. Hecht C. Koeberl E. Libowitzky W.U. Reimold article Hölttä201147 Metamorphic mineral assemblages and mineral compositions were investigated in metasediments of the Outokumpu drill hole from the surface to 2.5 km depth in order to determine the Proterozoic geothermal gradient. The common mineral assemblage of the mica gneisses is biotite-plagioclase-quartz±muscovite. Finegrained garnet and Al silicates (sillimanite, kyanite, andalusite) are locally found, whereas staurolite is rare. Small abundances of leucosome indicating the onset of partial melting are present, especially in the lower parts of the hole, which also show some grain-size coarsening. The Fe and Mg distribution coefficient (KD) between coexisting garnet and biotite increases slightly from the surface to the deeper levels, indicating increasing temperature. The garnet-biotite thermometer shows a slight increase in temperatures from c. 605-610 °C near the surface to c. 620-630 °C at 1200-1500 m depth, indicating an average gradient of 19 °C/km, but the result is within the error limits of the thermometer (±15 °C). Temperatures calculated using Thermocalc software are several tens of degrees higher. Metamorphic pressures calculated using the garnet-biotite-plagioclase- quartz and garnet-muscoviteplagioclase- quartz barometers and the Thermocalc average PT method are in the range from c. 4-9 kbars. Pressures given by fluid inclusion barometry are 2-5 kbars. Geobarometry does not indicate systematic changes as a function of the depth. A clockwise PT path, where pressure increased to 8-9 kbars and was followed by decompression down to the andalusite field, explains the observed mineral assemblages and thermobarometric results. Article 2011 English 978-952217152-8 07828535 Special Paper of the Geological Survey of Finland 2011 Kukkonen I.T. 47 – 62 51 Finland; Ita Suomen; Outokumpu; biotite; fluid inclusion; garnet; gneiss; grain size; iron; magnesium; metamorphism; metasediment; mica; mineralogy; P-T conditions; P-T-t path; partial melting; Proterozoic https://www.scopus.com/inward/record.uri?eid=2-s2.0-80051908795&partnerID=40&md5=061749191ad12bc9f8f7f333c9994ef8 Cited by: 4 Pentti Hölttä Petriikka Karttunen article Itävaara2011199 Three sampling campaigns were performed during the years 2007-2009 to develop microbiological sampling techniques and to study the deep biosphere in the Outokumpu Deep Drill Hole R2500, drilled into a Palaeoproterozoic sequence of rocks consisting of metasediments, ophiolite-derived altered ultramafic rocks and pegmatitic granite. The results revealed the presence of microbial communities in the saline fluids sampled from the open borehole and fracture systems in the low-porosity crystalline bedrock in Outokumpu. According to the microbiological analyses, the microbial cell density varies from 105 cells ml-1 at the surface to 103 ml-1 at 2350 m depth. The composition of microbial communities in the borehole was found to vary with sampling depth, and the changes appear to be connected to both geological and geochemical factors as well as to fracture zones in the bedrock. Sulphate reducing bacteria and methanogenic archaea are present throughout the borehole water column. Article 2011 English 978-952217152-8 07828535 Special Paper of the Geological Survey of Finland 2011 Kukkonen I.T. 199 – 206 51 Finland; Ita Suomen; Outokumpu; Bacteria (microorganisms); bacterium; bedrock; biosphere; borehole; fracture; granite; groundwater; metasedimentary rock; microbiology; microorganism; sampling; ultramafic rock; water column https://www.scopus.com/inward/record.uri?eid=2-s2.0-80051902876&partnerID=40&md5=5e3e8404d16f6213e756969b770e88d6 Cited by: 13 Merja Itävaara Mari Nyyssönen Malin Bomberg Anu Kapanen Aura Nousiainen Lasse Ahonen Jenni Hultman Lars Paulin Petri Auvinen Ilmo T. Kukkonen article Oliva-Urcia2011155 Active high-temperature (&gt;150 °C) geothermal areas like the Krafla caldera, NE-Iceland, often show distinct magnetic lows in aeromagnetic anomaly maps suggesting a destruction of magnetic minerals by hydrothermal activity. The main alteration processes in such an environment are low-temperature oxidation (&lt;350 °C, maghemitization) and fluid-rock interactions. We investigated the rock magnetic properties [natural remanent magnetization (NRM) magnetic susceptibility and their temperature and field variation] and the mineralogy, using X-ray diffraction, microscopic methods and electron microprobe analyses, of two drill cores (KH1 and KH3) from the rim of the Krafla caldera. The drill cores have distinctly lower NRM values (average &lt;3 A m-1) compared to younger surface basalts (average 20 A m-1) along with a large variation in magnetic susceptibility (1.3 × 10-7- 4.9 × 10-5 m3 kg-1). The secondary mineral assemblage (sulphides, sphene, rutile and chlorite) indicates an alteration within the chlorite-smectite zone for both cores without depth zoning. Optical miscroscopy in combination with the Bitter technique and backscatter electron microscopy along with the thermomagnetic analyses allow distinguishing two different magnetomineralogical groups of titanomaghemite: (1) titanomaghemite with intermediate titanium concentration and probably high vacancy concentration, and (2) titanomaghemite with low titanium concentration and low vacancy concentration. The mineral assemblages, textures and magnetic properties deduced from the mentioned magnetic measurements indicate two-stage transformation mechanism: (1) Dissolution of titanium at low pH under oxidizing conditions. The ulvöspinel component of titanomagnetite and ilmenite forms rutile or sphene, and Fe2 + migrates out of the spinel lattice forming titanomaghemite. (2) Formation of pyrite and dissolution of remaining titanomaghemite under reducing and acidic conditions. The latter mechanism produces ghost textures (all titanomaghemite is transformed and only their former grain shapes are preserved), with only paramagnetic minerals left and ferrimagnetic minerals nearly dissolved. This mechanism could explain the significant magnetization loss, which is seen in many local magnetic anomaly lows within the oceanic crust and volcanic islands like Iceland or Hawaii. The production of nanoporous textures in titanomaghemites is suggested as a mechanism for the enhancement of the magnetic susceptibility values related to the hydrothermal alteration of Krafla. © 2011 The Authors. Geophysical Journal International © 2011 RAS. 2011 English 0956540X 10.1111/j.1365-246X.2011.05029.x Geophysical Journal International 186 155-174 Institute of Applied Geosciences, Karlsruher Institute of Technology, Hertzstrasse 16, 76187, Germany; Dpto. Ciencias de la Tierra, Universidad de Zaragoza, C/ Pedro Cerbuna 12, 50009 Zaragoza, Spain; Eriksfiord AS, Kunnskapsparken, Postboks 8034, 4068 Stavanger, Norway; Geological Sciences, University of Michigan, 1100 CC, Little Building, Ann Arbor, MI, United States 1 Acidic conditions; Backscatter electron microscopy; Drill core; Ferrimagnetic minerals; Fluid-rock interaction; Geothermal areas; Geothermal systems; Grain shapes; High temperature; Hydrothermal activity; Hydrothermal alterations; Hydrothermal system; Icelands; Krafla caldera; Latter mechanism; Low-temperature oxidation; Magnetic anomalies; Magnetic mineralogy; Magnetic minerals; Magnetization loss; Microscopic methods; Mineral assemblage; Nano-porous; Natural remanent magnetization; Oceanic crust; Oxidizing conditions; Rock magnetic properties; Spinel lattices; Thermomagnetic analysis; Titanomagnetites; Two-stage transformations; Vacancy concentration; Volcanic islands, Basalt; Clay minerals; Concentration (process); Core drilling; Crystallography; Dissolution; Drills; Electron probe microanalysis; Geothermal fields; Lithology; Magnetic susceptibility; Magnetization; Mineralogy; Natural resources management; Oxide minerals; Paramagnetism; Petrography; Rocks; Silicates; Textures; Titanium; X ray diffraction; X ray diffraction analysis, Geomagnetism, basalt; caldera; chlorite; dissolution; geomagnetism; geothermal system; high temperature; hydrothermal activity; hydrothermal alteration; hydrothermal system; magnetic anomaly; magnetic susceptibility; magnetization; mineralogy; natural remanent magnetization; oceanic crust; oxidation; petrology; pyrite; smectite; volcanic island, Iceland; Krafla https://www.scopus.com/inward/record.uri?eid=2-s2.0-79959197694&doi=10.1111%2fj.1365-246X.2011.05029.x&partnerID=40&md5=6d71222c4f181f2dd087414772103f60 cited By 21 B. Oliva-Urcia A. Kontny C. Vahle article Lu2011125 A pair of series straight long-chain 2- and 1-alkyl naphthalenes (aNs) with alkyl chain carbon number up to 30 was detected in late Cretaceous sedimentary source rocks of the onshore Songliao Basin, NE China. Their sedimentary profile was shown to correlate positively with the relative abundances of several higher plant biomarkers including iP-iHMN and phenanthrene and weakly inversely with the relative abundance of alkylbenzenes. In contrast, the aNs distribution shows no relationship with hydrocarbon maturity indicators. The TOC, δ13C profile and other molecular features (e.g., CPI, OEP, Pr/Ph, Ga/C31H) were consistent with transgressive/regressive water cycles of the palaeo-lake of Songliao Basin. Decreasing Pr/Ph values in the upper horizon indicative of increasingly anoxic conditions. The distinctive occurrence and distribution of the long-chain aN compounds on the profile of the SK-1 borehole may imply some unique source inputs under particular lacustrine environmental conditions. Copyright © 2011 by The Geochemical Society of Japan. 2011 English 00167002 10.2343/geochemj.1.0108 Geochemical Journal 45 The Physiological Society of Japan 125-135 State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; WA Biogeochemistry and John De Laeter Mass Spectrometry Centres, University of Western Australia, Crawley-6009, WA, Australia 2 anoxic conditions; biomarker; Cretaceous; hydrocarbon resource; naphthalene; sedimentary rock; source rock; thermal maturity; total organic carbon, China; Songliao Basin, Embryophyta https://www.scopus.com/inward/record.uri?eid=2-s2.0-84877745971&doi=10.2343%2fgeochemj.1.0108&partnerID=40&md5=da7a003db7ded905ad56f696a5dc9b50 cited By 3 H. Lu L. Wang Z. Song P. Greenwood Q. Yin article Bräuer2011163 We report new data on gas and isotope compositions of mantle-derived exhalations from five locations in the Vogtland (Germany)/NW Bohemia (Czech Republic) area, close to the Nový Kostel focal zone, recorded by monthly sampling of gases over a three year period. This region is the locus typicus for the term "earthquake swarm"; since 1985/86 the largest numbers of earthquake swarms in the Vogtland/NW Bohemia have occurred in the Nový Kostel focal zone. Mantle-derived degassing has been studied at four locations within the Cheb Basin degassing centre, and at the Wettinquelle spring to the north on the edge of the Cheb Basin. The Bublák and U Mostku locations are on the Počatky Plesná Fault Zone (PPZ) while the Kopanina and Dolni Častkov locations are on the Mariánské Lázně Fault (MLF). The mantle-derived helium content at locations along the PPZ covers the range of the sub-continental lithospheric mantle (SCLM). Along the MLF the 3He/4He ratios are with up to 5.4Ra a little bit lower as at the PPZ locations. The CO2/3He ratios point to a predominantly magmatic source. Depending on the magnitude of gas flux the monthly sampling results indicated various major influences on the fluid signatures at the monitored locations due to seasonal cycles based on the different strong influence of CO2/water interaction. Micro-seismicity occurred repeatedly during the monitoring period and seismically triggered geochemical anomalies were repeatedly observed at the locations close to the focal zone. The 3He/4He ratios drop from 5.9Ra (mean) up to 5.6Ra at Bublák and from 5.6Ra up to 5.3Ra at U Mostku. A decrease in 3He/4He ratios was observed prior to seismic events due to stress accumulation before rupturing, and also after the events due to the release of crustal-derived components within the area of the focal zone. Due to the higher 'helium baseline content' of the Kopanina gas the 3He/4He ratios decreased there only from 4.6 to 4.5Ra. At the Wettinquelle, the most distant from the focal zone, the 3He/4He ratios ranged between 2.3 and 2.5Ra altogether. Superimposed to the seismically induced anomalies a clear three month-lasting increase of mantle-derived helium was observed at the locations on the PPZ. The 3He/4He ratios increased to 6.3Ra at Bublák and to 6.0Ra at U Mostku. An increase in the 3He/4He ratios was also noted at Kopanina (to 4.7Ra) and Dolni Častkov (to 5.4Ra), interpreted as indicating an ascent of less degassed magma (dyke intrusions) from the deeper lithospheric mantle reservoir. Superimposed geochemical effects initiated by the temporal and spatial evolution of a hidden magmatic-driven geodynamic process have therefore been observed in a continental rift system for the first time. © 2011 Elsevier B.V. Article 2011 English 00092541 10.1016/j.chemgeo.2011.09.012 Chemical Geology 290 163 – 176 3-4 Bohemia; Cheb Basin; Czech Republic; Germany; Karlovarsky; Vogtland; Carbon dioxide; Degassing; Earthquakes; Gases; Geochemistry; Geologic models; Helium; Isotopes; Magnetic leakage; He ratios; Cenozoic; Earthquake swarms; Magma intrusion; ; carbon dioxide; Cenozoic; degassing; earthquake swarm; focal mechanism; gas; helium isotope; igneous intrusion; isotopic composition; isotopic ratio; lithospheric structure; magma; mantle chemistry; rift zone; Focusing https://www.scopus.com/inward/record.uri?eid=2-s2.0-80055118337&doi=10.1016%2fj.chemgeo.2011.09.012&partnerID=40&md5=3a27d7c6eac830c478caddce5868437c Cited by: 52 Karin Bräuer Horst Kämpf Ulrich Koch Gerhard Strauch inproceedings astafieva2011multicellular 2011 SPIE Instruments, Methods, and Missions for Astrobiology XIV 8152 50--59 Marina M Astafieva Alexei Yu Rozanov Richard B Hoover article Janssen2011179 With transmission electron microscopy (TEM) we observed nanometer-sized pores in four ultracataclastic and fractured core samples recovered from different depths of the main bore hole of the San Andreas Fault Observatory at Depth (SAFOD). Cutting of foils with a focused ion beam technique (FIB) allowed identifying porosity down to the nm scale. Between 40 and 50% of all pores could be identified as in-situ pores without any damage related to sample preparation. The total porosity estimated from TEM micrographs (1-5%) is comparable to the connected fault rock porosity (2.8-6.7%) estimated by pressure-induced injection of mercury. Permeability estimates for cataclastic fault rocks are 10-21-10-19 m2 and 10-17 m2 for the fractured fault rock. Porosity and permeability are independent of sample depth. TEM images reveal that the porosity is intimately linked to fault rock composition and associated with deformation. The TEM-estimated porosity of the samples increases with increasing clay content. The highest porosity was estimated in the vicinity of an active fault trace. The largest pores with an equivalent radius&gt;200nm occur around large quartz and feldspar grains or grain-fragments while the smallest pores (equivalent radius&lt;50nm) are typically observed in the extremely fine-grained matrix (grain size&lt;1&gt;m). Based on pore morphology we distinguish different pore types varying with fault rock fabric and alteration. The pores were probably filled with formation water and/or hydrothermal fluids at elevated pore fluid pressure, preventing pore collapse. The pore geometry derived from TEM observations and BET (Brunauer, Emmett and Teller) gas adsorption/desorption hysteresis curves indicates pore blocking effects in the fine-grained matrix. Observations of isolated pores in TEM micrographs and high pore body to pore throat ratios inferred from mercury injection suggest elevated pore fluid pressure in the low permeability cataclasites, reducing shear strength of the fault. © 2010 Elsevier B.V. 2011 English 0012821X 10.1016/j.epsl.2010.10.040 Earth and Planetary Science Letters 301 179-189 GFZ German Research Centre for Geosciences, Telegrafenberg, 14473 Potsdam, Germany; Department of Earth and Planetary Science, University of California, Berkeley, CA, United States 1-2 Fault rock; Permeability; SAFOD; San Andreas Fault; TEM, Core samples; Fluids; Ion beams; Mercury (metal); Porosity; Quartz; Rocks; Shear strength; Silicate minerals; Tectonics; Transmission electron microscopy, Structural geology, cataclasite; fault zone; feldspar; fluid pressure; hydrothermal fluid; permeability; porosity; quartz; San Andreas Fault; shear strength; transmission electron microscopy https://www.scopus.com/inward/record.uri?eid=2-s2.0-78650257877&doi=10.1016%2fj.epsl.2010.10.040&partnerID=40&md5=62106fb0f8797a5639df8e10800deca4 cited By 53 C. Janssen R. Wirth A. Reinicke E. Rybacki R. Naumann H.-R. Wenk G. Dresen article Lippmann-Pipke2011287 The deep gold mines of the Witwatersrand Basin, South Africa have gained recent attention not only because of investigations of the deep fracture water and associated CH4- and H2-rich gases found there, but because of recent reports of deep microbial communities persisting to depths of almost 3km - an exotic outpost of the Earth's deep biosphere. While shallower fluids in the basin (to approximately 1km) were found to contain abundant populations of methanogens and sulphate-reducing bacteria, the deepest, oldest, most saline fracture waters in the basin hosted hitherto unrecognised low biomass and low biodiversity chemoautotrophic ecosystems independent from the photosphere. Shallow and deep fluids also show distinct differences in gas and fluid geochemistry. Paleometeoric waters are dominated by hydrocarbon gases with compositional and isotopic characteristics consistent with production by methanogens utilising the CO2 reduction pathway. In contrast the deepest, most saline fracture waters contain gases that are dominated by high concentrations of H2 gas, and CH4 and higher hydrocarbon gases with isotopic signatures attributed to abiogenic processes of water-rock reaction. The high salinities (up to hundreds of g/L), highly altered δ18O and δ2H signatures, and both 36Cl and measurements of co-occurring nucleogenic noble gases for these fracture waters are consistent with extensive water-rock interaction over geologically long time scales in these high rock/water ratio environments. While the ultimate origin of these fluids has been attributed alternately to saline waters that penetrated the crystalline basement, formation water, or hydrothermal fluids in some cases, their δ18O and δ2H isotopic signatures have typically been so profoundly overprinted by the effects of long-term water-rock interaction that, for the most saline end-members, little evidence of their primary composition remains. The key objective of the present study is to further investigate the origin of these fluids by integrating for the first time detailed neon isotope analyses on the dissolved gases. Helium isotopic analysis confirmed that there is no significant mantle-derived component associated with these fluids and gases. Neon isotope results show distinct differences in neon composition that correspond to the different fluid geochemical end-members previously identified. Typical crustal neon signatures (type A) are identified in the paleometeoric waters populated with abundant methanogens. In contrast, the deep more saline fracture waters contain an enriched nucleogenic neon signature unlike any previously reported in crustal fluids. These samples show the highest 21Ne/22Ne ratios (0.160±0.003) ever reported in groundwater. Fluid inclusions in these rocks yield even higher 21Ne/22Ne ratios between 0.219 and 0.515, consistent with an extrapolated 21Ne/22Ne value of 3.3±0.2 at 20Ne/22Ne=0. We show that this enriched nucleogenic neon end-member represents a fluid component that was produced in the fluorine-depleted Archaean formations and trapped in fluid inclusions ≥2Ga ago. The observation of enriched nucleogenic neon signatures in deep fracture water implies the release of this billion year old neon component from the fluid inclusions and its accumulation in exceptionally isolated fracture water systems. The observed association of this Archean neon signature with H2-hydrocarbon-rich geogases of proposed abiogenic origin dissolved in the same deep groundwater suggests that the fracture systems have also allowed for the accumulation of various products of water-rock reactions throughout geologic times. One of these fracture systems contained the deepest characterised microbial ecosystems on earth - chemolithotrophs eking out an existence at maintenance levels independent from sunlight. Consequently, the enriched nucleogenic neon isotope signature may indicate regions in the Archaean crust where investigations of the deep biosphere might be focused. © 2011 Elsevier B.V. 2011 English 00092541 10.1016/j.chemgeo.2011.01.028 Chemical Geology 283 287-296 Helmholtz Zentrum Dresden Rossendorf, Institute of Radiochemistry, Research Site Leipzig, Permoserstr. 15, 04318 Leipzig, Germany; Department of Geology, University of Toronto, 22 Russell Street, Toronto, M5S 3B1, Canada; Helmholtz-Zentrum Potsdam, Deutsches GeoForschungsZentrum, Telegrafenberg, 14473 Potsdam, Germany; Department of Microbial, Biochemical and Food Biotechnology, University of the Free State, P.O. Box 339, Bloemfontein 9300, South Africa; Department of Geosciences, Princeton University, Guyot Hall, Princeton, NJ 08544, United States 3-4 Abiogenic; Abiogenic origin; Archaean; Archean; Chemolithotrophs; Crustal fluid; Crystalline basement; Deep fluids; Deep fractures; Deep gold mines; Deep groundwaters; Dissolved gas; Endmembers; Fluid components; Fluid geochemistry; Fluid inclusion; Formation water; Fracture systems; Fracture water; High concentration; High salinity; Higher hydrocarbons; Hydro-carbon gas; Hydrothermal fluids; Isotopic analysis; Isotopic characteristics; Isotopic signatures; Key objective; Maintenance levels; Metamorphic fluids; Microbial communities; Microbial eco system; Neon isotopes; Noble gas; South Africa; Subsurface microbiology; Sulphate reducing bacteria; Time-scales; Water rock interactions; Water-rock reactions, Analytical geochemistry; Biodiversity; Biospherics; Ecosystems; Fluids; Fluorine; Fracture; Gallium; Gas fuel analysis; Gold mines; Groundwater; Groundwater geochemistry; Helium; Hydrocarbons; Inert gases; Isotopes; Methanogens; Microbiology; Mineralogy; Rock products; Saline water; Weathering, Neon, concentration (composition); isotopic composition; methanogenesis; microbial community; neon; noble gas; water chemistry; water-rock interaction, South Africa; Witwatersrand https://www.scopus.com/inward/record.uri?eid=2-s2.0-79953281570&doi=10.1016%2fj.chemgeo.2011.01.028&partnerID=40&md5=c058436c02658727d728a7bcda351e8b cited By 63 J. Lippmann-Pipke B. Sherwood Lollar S. Niedermann N.A. Stroncik R. Naumann E. Heerden T.C. Onstott article huang2011new 2011 Journal of Stratigraphy 35 250-257 3 QH Huang HC Wu XQ Wan HY He CL Deng article Uddin201170 Gas hydrates are a potentially vast untapped source of natural gas. Recent numerical and field studies suggest the Mallik gas-hydrate field in Canada's Mackenzie Delta may represent a technically producible and potentially economically viable reservoir of natural gas. Our initial reservoir simulations using a kinetic reaction approach indicate that gas evolution and transport within porous geologic reservoirs have a significant effect on fluid production characteristics, while field and laboratory data suggest that significant amounts of evolved gas can be trapped for some time within the reservoir, depending on the field operation. In this work, we invoke modelling concepts extensively employed in quantifying gas ex-solution from viscous oils to further assess the kinetic behaviour of gas-hydrate ex-solution through depressurization. Here, the gas bubbles can be categorized into three groups with explicit transport behaviour: small bubbles (water phase), large bubbles (immobile) and connected bubbles (or free gas). These concepts allow the development of a new set of kinetic reactions for hydrate dissociation: one representing the (possibly delayed) conversion of hydrate into water and dispersed gas bubble phases, and one representing the evolution from dispersed bubbles to connected bubbles. These reactions can effectively capture the nonequilibrium fluidflow behaviour observed in field production tests. For modelling of the transport phenomenon, we assumed two explicit mobility formulations: (1) trapped bubbles (no mobility) and a flowing water phase and (2) large connected gas bubbles and flowing water (with relative mobility). Relative mobility can be estimated by using traditional gridblock-relative permeability curves. We then develop a simple mechanistic gas bubble trapping tool as a function of the capillary number, which can easily be incorporated into our numerical simulator. This entrapment of the nonwetting gas-phase results in higher values of critical gas saturation. Two case studies based on alternative representations of a Mallik-like gas-hydrate reservoir demonstrate that significant errors can result in reservoir modelling if these fluid transport phenomena are not adequately represented in numerical simulations. Aspects of the model developed here have been applied to history matching and prediction of natural gas recovery from a clastic, sand-dominated reservoir at the Mallik site. 2011 English 00219487 10.2118/137439-pa Journal of Canadian Petroleum Technology 50 Society of Petroleum Engineers (SPE) 70-88 Alberta Innovates-Technology Futures, Canada; Geological Survey of Canada, Natural Resources Canada, Canada; Computer Modelling Group. Ltd., Canada 1 Bubbles (in fluids); Gas hydrates; Gas oils; Gases; Hydration; Kinetics; Natural gas; Natural gasoline plants; Petroleum reservoirs; Transport properties, Critical gas saturation; Gas hydrate reservoir; Hydrate dissociation; Natural gas hydrate reservoir; Natural gas recoveries; Numerical simulators; Relative permeability curves; Reservoir simulation, Natural gas fields https://www.scopus.com/inward/record.uri?eid=2-s2.0-79551698525&doi=10.2118%2f137439-pa&partnerID=40&md5=38b246105db3719af37fbc2e94be23b0 cited By 21 M. Uddin F. Wright D. Coombe conference Johri2011 We report a study on sub-surface fault damage zones adjacent to faults in a gas field in Southeast Asia and near the San Andreas Fault in central California. The importance of characterizing damage zones arises from the important role that damage zones and natural fractures play in governing fluid flow through low permeability reservoirs. While there are many published studies of exposed damage zones (principally associated with now dormant faults), there is an absence of subsurface data that characterizes damage zones at depth associated with active faults. The first region of study is a fault zone in a gas reservoir in Southeast Asia. A large, basement master fault is associated with twenty-seven seismically-resolvable second-order faults. Five to six fractures per meter are observed in electrical image logs from five wells in the 50-80m wide damage zones of the second-order faults. Damage zones associated with second-order faults adjacent to the San Andreas Fault are studied in well-cemented arkosic sandstones immediately southwest of the main fault at the SAFOD site. Damage zone widths associated with second-order faults are typically on the order of 50-100 meters whereas the damage zone associated with the San Andreas Fault is about 250 meters wide. The density of the third-order faults in damage zones observed in both the areas of study is found to decrease exponentially with distance. © 2011 ARMA, American Rock Mechanics Association. 2011 English 45th US Rock Mechanics / Geomechanics Symposium Stanford University, Stanford, CA, United States; Conoco Phillips, Houston, TX, United States Active fault; California; Damage zones; Electrical images; Fault damage zone; Fault zone; Gas fields; Gas reservoir; Natural fracture; San Andreas Fault; Second orders; Southeast Asia; Sub-surfaces; Subsurface data; Third-order, Flow of fluids; Fracture; Gas industry; Petroleum reservoir engineering; Rock mechanics, Low permeability reservoirs https://www.scopus.com/inward/record.uri?eid=2-s2.0-82655183530&partnerID=40&md5=4a7344c63e7fc763235a9666fb80c68f cited By 3 M. Johri M.D. Zoback P. Hennings article Kukkonen201156 2011 English 18168957 10.2204/iodp.sd.11.08.2011 Scientific Drilling 56-59 Geological Survey of Finland, Espoo, P.O. Box 96, FI-02151 Espoo, Finland; Luleå University of Technology, SE-971 87 Luleå, Sweden; Geological Survey of Norway, NO-7491 Trondheim, Norway 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-79955131407&doi=10.2204%2fiodp.sd.11.08.2011&partnerID=40&md5=e56fa9ead803b563bd44397f17a09c15 cited By 6 I.T. Kukkonen M.V.S. Ask O. Olesen article Virgil2011119 In September 2008, the magnetic field in the Outokumpu Deep Drill Hole (OKU R2500) was measured with the Göttinger Bohrloch Magnetometer (GBM). Unlike previous total field measurements with other tools, the three components of the magnetic field and the tool attitude were measured continuously with a resolution of up to 5 cm. This became possible by utilizing a unique orientation system consisting of three fibre optic gyros. After extensive data processing, the magnetic anomalies along the borehole were obtained in the geographic coordinates North, East and Vertical (WGS-84). Two intervals with significant magnetic anomalies were detected. While the disturbances in the first interval (70-300 m) are either manmade or caused by thin layers of black schist, the second interval (1328-1440 m) is dominated by magnetized rocks of the Outokumpu assemblage. The combined interpretation of core data and in-situ measurements indicates less carbonated serpentinite as the host for magnetic minerals. Furthermore, statistical studies of the magnetisation direction, derived from the GBM measurements, suggest a different geological evolution of the host rocks of the upper and lower section of the Outokumpu assemblage. Article 2011 English 978-952217152-8 07828535 Special Paper of the Geological Survey of Finland 2011 Kukkonen I.T. 119 – 132 51 Finland; Ita Suomen; Outokumpu; Gyros; borehole logging; data processing; deep drilling; magnetic anomaly; magnetic field; magnetometer; metamorphic rock; remanent magnetization https://www.scopus.com/inward/record.uri?eid=2-s2.0-80051894711&partnerID=40&md5=ebfeaf2f0dc88721e341ffd0960577b0 Cited by: 4 Christopher Virgil Andreas Hördt Martin Leven Erich Steveling Jochem Kück Frank Dietze conference Potter2011967 Preliminary stratigraphic sections for Project Hotspot's Kimama drill hole based on gamma and neutron logs correlate well with lithologic observations. The gamma logs document the depth and thickness of sedimentary interbeds, whereas the neutron logs respond to the contrast between massive flow interiors and more porous flow tops. These data show the presence of at least 550 basalt flows (0.1-50 m thick), grouped into at least 30 flow groups, 13 m to 170 m thick (most 20-100 m thick). Flows are designated based upon morphological characteristics, including the presence of rubbly, highly fractured flow tops, massive to vesicular flow interiors, and rubbly flow bases; flow groups are commonly separated by sedimentary interbeds, which range in thickness from 0.2 m to 50 m. Increased conductivity along basalt flow unit contacts and associated fractures is a well-documented trend in the subsurface stratigraphy of the SRP. Determining the location of permeable basalt flow unit contacts and impermeable sediment layers is necessary to understand the flow of groundwater and potentially, geothermal fluid. The compilation of well log data shows an apparent agreement between lithologic and geophysical stratigraphy, with observed basalt flow unit contacts and sediment interbeds at least roughly mirrored by spikes and dips in natural gamma and neutron log signals. Natural gamma logs have the additional capability of identifying more evolved, high potassium basalt compositions through signal peaks that are unrelated to lithologic flow boundaries. These observations demonstrate the usefulness of wireline geophysical data to determine basalt flow group boundaries, flow compositions, and probable fluid transport avenues. Conference paper 2011 English 978-161839482-8 01935933 Transactions - Geothermal Resources Council 35 2 967 – 971 Basalt; Geothermal fields; Geothermal prospecting; Groundwater; Neutrons; Potassium; Sedimentology; Stratigraphy; Transport properties; Basalt flow; Drill hole; Flow boundaries; Fluid transport; Geophysical data; Geothermal; Geothermal fluids; Geothermal potential; Group boundary; Hot spot; Morphological characteristic; Neutron log; Porous flow; Rhyolite; Sediment layers; Snake river plains; Subsurface stratigraphy; Well log data; Neutron logging https://www.scopus.com/inward/record.uri?eid=2-s2.0-84860873176&partnerID=40&md5=d56d0f5579147918e8a621facf592a4b Cited by: 10 Katherine E. Potter Richard Bradshaw Christopher J. Sant Jesse King John W. Shervais Eric J. Christiansen article Lin2025 Article 2011 10.3799/dqkx.2011.045 Earth Science-Journal of China University of Geosciences 36 409-428 03 H. Wu S. Zhang Q. Feng N. Fang T. Yang H. Li article huo2011advance 2011 Journal of Jilin University(Earth Science Edition) 41 Jilin University, 6 Ximinhu Street Changchun China 586-591 2 Q-L Huo H-S Zeng Li Fu Z-G Ren article Urrutia-Fucugauchi201199 The Chicxulub impact crater is part of a select group of unique geological sites, being a natural laboratory to investigate crater formation processes and global effects of large-scale impacts. Chicxulub is one of only three multi-ring craters documented in the terrestrial record and impact has been related to the global environmental/climatic effects and mass extinction that mark the Cretaceous/Paleogene (K/Pg) boundary. The crater is buried under ~1.0 km of carbonate sediments in the Yucatan peninsula. The buried structure was initially identified from geophysical surveys of the PEMEX oil exploration program in southeastern Mexico. On the surface its influence is marked by the circular ring of cenotes that have formed from differential compaction and fracturing between the impact breccias and surrounding limestone sequences. The crater is about ~200 km in rim diameter, half on-land and half off-shore with geometric center at Chicxulub Puerto, making it possible to use land, marine and aerial geophysical methods. The Yucatan carbonate platform is an ideal place to have the crater, tectonically stable with no volcanic activity, having formed by slow deposition of carbonate sediments. These characteristics permit high resolution imagery of the crater underground structure with unprecedented detail. The impact and crater formation occur instantaneously, with excavation of the crust down to ~25 km depths in fractions of a second and lower crust uplift and crater formation in the next few hundred seconds. Energy release results in intense fracturing and deformation at the target site, generating seismic waves traveling the whole Earth. Understanding the physics of impacts on planetary surfaces and modeling of crustal deformation and rheological behavior of materials at high temperatures and pressures remain major challenges in geosciences. The K/Pg ejecta layer is the only global stratigraphic marker in the geological record, allowing correlation of events worldwide. In the last 20 years much has been learned about the Chicxulub crater and the K/Pg boundary; however what is perhaps most interesting are the questions remaining, which include fundamental aspects of Chicxulub impact and its environmental effects. 2011 Geofisica Internacional 50 99-127 Proyecto Universitario de Perforaciones en Océanos y Continentes, Instituto de Geofísica, Universidad Nacional Autónoma de México, Delegación Coyoacan 04510, Mexico; Petróleos Mexicanos, PEMEX Exploración y Producción (retired), Blvd. A. Ruiz Cortines 1202, Villahermosa, Tabasco, 86030, Mexico; Facultad de Ingeniería, Universidad Nacional Autónoma de México, Delegación Coyoacan 04510, Mexico 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-78650813917&partnerID=40&md5=866bb9cf94dfafac2322449068c38646 cited By 34 J. Urrutia-Fucugauchi A. Camargo-Zanoguera L. Pérez-Cruz G. Pérez-Cruz article Breuker2011 For the first time quantitative data on the abundance of Bacteria, Archaea, and Eukarya in deep terrestrial sediments are provided using multiple methods (total cell counting, quantitative real-time PCR, Q-PCR and catalyzed reporter deposition-fluorescence in situ hybridization, CARD-FISH). The oligotrophic (organic carbon content of ̃0.2%) deep terrestrial sediments in the Chesapeake Bay area at Eyreville, Virginia, USA, were drilled and sampled up to a depth of 140 m in 2006. The possibility of contamination during drilling was checked using fluorescent microspheres. Total cell counts decreased from 109 to 106 cells/g dry weight within the uppermost 20 m, and did not further decrease with depth below. Within the top 7 m, a significant proportion of the total cell counts could be detected with CARD-FISH.The CARD-FISH numbers for Bacteria were about an order of magnitude higher than those for Archaea. The dominance of Bacteria over Archaea was confirmed by Q-PCR. The down core quantitative distribution of prokaryotic and eukaryotic small sub- unit ribosomal RNA genes as well as functional genes involved in different biogeochemical processes was revealed by Q-PCR for the uppermost 10 m and for 80-140 m depth. Eukarya and the Fe(III)- and Mn(IV)-reducing bacterial group Geobacteriaceae were almost exclu- sively found in the uppermost meter (arable soil), where reactive iron was detected in higher amounts. The bacterial candidate division JS-1 and the classes Anaerolineae and Caldilineae of the phylum Chloroflexi, highly abundant in marine sediments, were found up to the maximum sampling depth in high copy numbers at this terrestrial site as well. A similar high abundance of the functional gene cbbL encoding for the large subunit of RubisCO suggests that autotrophic microorganisms could be relevant in addition to het- erotrophs. The functional gene aprA of sulfate reducing bacteria was found within distinct layers up to ca. 100 m depth in low copy numbers.The gene mcrA of methanogens was not detectable. Cloning and sequencing data of 16S rRNA genes revealed sequences of typi- cal soil Bacteria. The closest relatives of the archaeal sequences were Archaea recovered from terrestrial and marine environments. Phylogenetic analysis of the Crenarchaeota and Euryarchaeota revealed new members of the uncultured South African Gold Mine Group, Deep Sea Hydrothermal Vent Euryarchaeotal Group 6, and Miscellaneous Crenarcheotic Group clusters. © 2011 Breuker, Köweker, Blazejak and Schippers. 2011 English 1664302X 10.3389/fmicb.2011.00156 Frontiers in Microbiology 2 Frontiers Research Foundation Geomicrobiology, Federal Institute for Geosciences and Natural Resources, Hannover, Germany; Faculty of Natural Sciences, Leibniz Universität Hannover, Hannover, Germany; Max Planck Institute for Marine Microbiology, Bremen, Germany JULY Anaerolineae; Archaea; Bacteria (microorganisms); candidate division JS1; Chloroflexi; Chloroflexi (class); Crenarchaeota; Eukaryota; Euryarchaeota; Prokaryota https://www.scopus.com/inward/record.uri?eid=2-s2.0-84870320616&doi=10.3389%2ffmicb.2011.00156&partnerID=40&md5=5f8e1449e7d2d3db36f5bd20726c33cf cited By 38 A. Breuker G. Köweker A. Blazejak A. Schippers article 2011 Science Technology and Engineering 11 461-466 3 G. Han W. Zhang Q. Huang conference Frioleifsson2011347 The Iceland Deep Drilling Project (IDDP) is being carried out by an international industry-government consortium in Iceland, in order to investigate the economic feasibility of producing electricity from supercritical geothermal reservoirs. Modeling suggests that producing superheated steam from a supercritical reservoir could potentially increase power output of geothermal wells by an order of magnitude. To test this concept, the consortium planned to drill a deep well in each of three different geothermal fields in Iceland, namely, Krafla, and at the Hengill and Reykjanes fields in SW-Iceland. In 2009 the drilling of the first deep well, IDDP-1, was attempted in the active central volcano at Krafla in NE Iceland. However the drilling had to be terminated at 2.1 km depth when 900°C rhyolite magma was intersected. The well, IDDP-1, was highly productive, capable of producing some 25 MWe from 380°C superheated steam during a flow test undertaken in 2010. The well was shut in August 2010, to allow the wellhead and surface equipment to be modified to withstand corrosive fluids. Starting in May 2011 flow-testing, wet and dry scrubbing of the steam and a test of a heat exchange system will be conducted. This flow test is expected to last through the rest of 2011. Preliminary results from these tests should be available to report at the GRC Annual Meeting in October 2011. The second deep IDDP well, IDDP-2, could possibly be drilled to 4-5 km depth as early as 2012-2013, into the saline Reykjanes high-temperature field in SW-Iceland. The design of the IDDP-2 well will benefit from lessons learned during drilling of the IDDP-1 at Krafla. Here we review the geological and geophysical characteristics of the Reykjanes field, based on pre-existing and very recent data. According to both 1 dimensional and 3 dimensional interpretations of the new magnetotelluric (MT) data, the IDDP-2 site is located above a major heat source occurring at some 10 km depth. 2011 English 9781618394828 01935933 Transactions - Geothermal Resources Council 35 1 347-354 HS Orka hf, Reykjanesbaer, Iceland; Department of Earth Sciences, University of California, Riverside, CA, United States; ISOR, Iceland GeoSurvey, Reykjavík, Iceland; Landsvirkjun, Reykjavik, Iceland 3-dimensional; Black smokers; Corrosive fluids; Deep drilling; Deep wells; Economic feasibilities; Flow tests; Geothermal reservoir; Heat exchange systems; Heat sources; High temperature; Icelands; Power out put; Super-critical; Superheated steam; Surface equipment; Wet and dry, Deep oil well drilling; Effluent treatment; Geothermal fields; Geothermal prospecting; Supercritical fluids, Geothermal wells https://www.scopus.com/inward/record.uri?eid=2-s2.0-84860873592&partnerID=40&md5=2031d66c914d41627f225d860cdbbad0 cited By 17 G.O. Frioleifsson A. Albertsson W.A. Elders O. Sigurdsson R. Karlsdóttir B. Pálsson article Melles201129 Between October 2008 and May 2009, the International Continental Scientific Drilling Program (ICDP) co-sponsored a campaign at Lake El'gygytgyn, located in a 3.6-Ma-old meteorite impact crater in northeastern Siberia. Drilling targets included three holes in the center of the 170-m-deep lake, utilizing the lake ice cover as a drilling platform, plus one hole close to the shore in the western lake catchment. At the lake's center. the entire 315-m-thick lake sediment succession was penetrated. The sediments lack any hiatuses (i.e., no evidence of basin glaciation or desiccation), and their composition reflects the regional climatic and environmental history with great sensitivity. Hence, the record provides the first comprehensive and widely timecontinuous insights into the evolution of the terrestrial Arctic since mid-Pliocene times. This is particularly true for the lowermost 40 meters and uppermost 150 meters of the sequence, which were drilled with almost 100% recovery and likely reflect the initial lake stage during the Pliocene and the last ~2.9 Ma, respectively. Nearly 200 meters of underlying rock were also recovered; these cores consist of an almost complete section of the various types of impact breccias including broken and fractured volcanic basement rocks and associated melt clasts. The investigation of this core sequence promises new information concerning the El'gygytgyn impact event, including the composition and nature of the meteorite, the energy released, and the shock behavior of the volcanic basement rocks. Complementary information on the regional environmental history, including the permafrost history and lake-level fluctuations, is being developed from a 142-m-long drill core recovered from the permafrost deposits in the lake catchment. This core consists of gravelly and sandy alluvial fan deposits in ice-rich permafrost, presumably comprising a discontinuous record of both Quaternary and Pliocene deposits. 2011 English 18168957 10.2204/iodp.sd.11.03.2011 Scientific Drilling Copernicus GmbH 29-40 Institute of Geology and Mineralogy, University of Cologne, Zuelpicher Str. 49a, D-50674 Cologne, Germany; Department of Geosciences, University of Massachusetts, 611 North Pleasant Street, Amherst, MA 01003, United States; North-East Interdisciplinary Scientific Research Institute, FEB RAS, 16 Portovaya St., 685000, Magadan, Russian Federation; Department of Lithospheric Research, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria; Natural History Museum, A-1010 Vienna, Austria; Arctic and Antarctic Research Institute, Bering Street, 199397 St. Petersburg, Russian Federation; Alfred Wegener Institute for Polar and Marine Research, Am Alten Hafen 26, D-27568 Bremerhaven, Germany; GFZ German Research Centre for Geosciences, Potsdam, Telegrafenberg C321, D-14473 Potsdam, Germany; Alfred Wegener Institute for Polar and Marine Research, Telegrafenberg A43, D-14473 Potsdam, Germany 1 Anoxic sediments; Catchments; Core drilling; Deposits; Drilling platforms; Glacial geology; Meteor impacts; Meteorites; Permafrost; Recovery; Runoff; Sedimentology; Volcanic rocks; Volcanoes, Alluvial fans; Basement rocks; Drill core; Drilling targets; Environmental history; Ice cover; Ice-rich permafrost; Impact events; Information concerning; Lake sediments; Level fluctuation; Meteorite impact; Mid-Pliocene; Pliocene; Pliocene deposits; Scientific drilling; SIBERIA; Underlying rocks, Lakes https://www.scopus.com/inward/record.uri?eid=2-s2.0-79955134100&doi=10.2204%2fiodp.sd.11.03.2011&partnerID=40&md5=0cb1852bef890c3dff80747bd19e7372 cited By 66 M. Melles J. Brigham-Grette P. Minyuk C. Koeberl A. Andreev T. Cook G. Fedorov C. Gebhardt E. Haltia-Hovi M. Kukkonen N. Nowaczyk G. Schwamborn V. Wennrich article Popov2011729 The results of thermal property measurements on cores from the scientific well Yaxcopoil-1 (1511 m in depth) drilled in the Chicxulub impact structure (Mexico) are described. The thermal conductivity, thermal diffusivity, volumetric heat capacity, thermal anisotropy coefficient, thermal heterogeneity factor, and, in addition, porosity and density were measured on 451 dry and water-saturated cores from the depth interval of 404-1511 m. The acoustic velocities were determined on a subgroup of representative samples. Significant vertical short- and long-scale variations of physical properties related to the grade of shock-thermal metamorphism and correlations between thermal and other physical properties are established. Rocks of the post-impact and impact complexes differ significantly in heterogeneity demonstrating that the impact complex has larger micro- heterogeneity on sample scale. The pre-impact rocks differ essentially from the impact and post-impact rocks in the thermal conductivity, thermal diffusivity, density and porosity. The thermal anisotropy of rocks of all structural-lithological complexes is very low (K = 1.02 ... 1.08), which is similar to the situation in the Puchezh-Katunk and Ries impact structures. Correlations are established between the thermal conductivity and elastic wave velocities measured in laboratory. For limestone-calcarenites, the thermal conductivity (λ) can be calculated from the compressional wave velocity (Vp) using the formula λ= 0.346 Vp + 0.844, and for dolomite-anhydrites this relation has the form λ= 0.998 Vp + 1.163 [for λ in W (m K)-1 and Vp in km s-1]. These correlations are used for downscaling of the sonic velocities to the decimetre scale. The effective medium theory is applied to invert the matrix thermal conductivity and pore/crack geometry from the thermal conductivity measured on the studied samples. Representative experimental data on the thermal properties for all lithological groups encountered by the Yaxcopoil-1 well essentially extend an existing database on the thermal properties of rocks of impact structures and can be used for determination of the heat flow density, interpretation of temperature logging data, theoretical modelling of heat and mass transfer processes and constructing thermal models of the Chicxulub impact structure as well as for the lithological interpretation. The research results confirm the necessity of dense sampling for the thermal property measurements to obtain reliable results in petrophysical and geothermal investigations of impact structure formations. © 2010 The Authors Geophysical Journal International © 2010 RAS. 2011 10.1111/j.1365-246X.2010.04839.x Geophysical Journal International 184 729-745 Moscow State Geological Prospecting University, Russian Federation; Fachgebeit Angewante Geophysik, Technische Universitaet Berlin, Sekr. ACK 2, Ackerstrasse 71-76, D-13355, Berlin, Germany; Geophysical Institute, University Karlsruhe, Germany 2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-78751542871&doi=10.1111%2fj.1365-246X.2010.04839.x&partnerID=40&md5=74ed70699096d3d674d3af7da0028881 cited By 17 Y. Popov R. Romushkevich D. Korobkov S. Mayr I. Bayuk H. Burkhardt H. Wilhelm article Bulut20111759 We investigate earthquakes with similar waveforms in order to characterize spatiotemporal microseismicity clusters within the North Anatolian fault zone (NAFZ) in northwest Turkey along the transition between the 1999 İzmit rupture zone and the Marmara Sea seismic gap. Earthquakes within distinct activity clusters are relocated with cross-correlation derived relative travel times using the double difference method. The spatiotemporal distribution of micro earthquakes within individual clusters is resolved with relative location accuracy comparable to or better than the source size. High-precision relative hypocenters define the geometry of individual fault patches, permitting a better understanding of fault kinematics and their role in local-scale seismotectonics along the region of interest. Temporal seismic sequences observed in the eastern Sea of Marmara region suggest progressive failure of mostly nonoverlapping areas on adjacent fault patches and systematic migration of microearthquakes within clusters during the progressive failure of neighboring fault patches. The temporal distributions of magnitudes as well as the number of events follow swarmlike behavior rather than a mainshock/aftershock pattern. 2011 English 00371106 10.1785/0120100215 Bulletin of the Seismological Society of America 101 1759-1768 Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences, Telegrafenberg, Haus D, Potsdam D-14473, Germany; U.S. Geological Survey, 345 Middlefield Road, Menlo Park, CA 94025-3591, United States; Boǧaziçi University, Kandilli Observatory and Earthquake Research Institute, 34342 Bebek, Çengelköy, Istanbul 34684, Turkey 4 Cross correlations; Double differences; Fault kinematics; High-precision; Mainshock; Marmara Sea; Micro-earthquakes; Microseismicity; North Anatolian Fault Zone; Northwest Turkey; Progressive failure; Region of interest; Relative location; Rupture zone; Seismic sequence; Seismotectonics; Source sizes; Spatiotemporal distributions; Temporal distribution; Travel time; Wave forms, Image segmentation, Earthquakes, accuracy assessment; aftershock; earthquake catalogue; earthquake hypocenter; earthquake magnitude; earthquake mechanism; earthquake rupture; earthquake swarm; fault zone; Kocaeli earthquake 1999; microearthquake; spatiotemporal analysis; tectonic setting, Anatolia; Sea of Marmara; Turkey https://www.scopus.com/inward/record.uri?eid=2-s2.0-79961157143&doi=10.1785%2f0120100215&partnerID=40&md5=93cbd4130014d0e7a040ea945f708b7c cited By 18 F. Bulut W.L. Ellsworth M. Bohnhoff M. Aktar G. Dresen article Müller2011645 Seven eclogite samples from 223 to 584 m depths in the Chinese Continental Scientific Drilling main borehole (CCSDMH) in the Sulu ultrahigh-pressure metamorphic (UHPM) terrane, Eastern China, were studied by transmission electron microscopy (TEM), in order to characterise their microstructures. We observed, among others, omphacite, jadeitic diopside, garnet, amphibole, rutile, Na-rich plagioclase, quartz, K-feldspar, analcime, and diamond (contamination). Omphacite shows a well-known diffusioncontrolled disorder-order phase transition which gives rise to antiphase domains (APDs). In our samples we observed a variation of the APDs' size between ∼5 nm and 2 mm which is correlated with the content in jadeite (Jd) component. The broad maximum of ∼1-2 mm APDs' size is centred on Jd50. This size drops to ∼5-10 nm for Jd37 and Jd66. The size variation can be explained with the T-path of the respective omphacites. While the large APDs of the omphacites formed and coarsened during subduction and exhumation, the smallest APDs formed and grew during exhumation. In contrast to other eclogite occurrences, deformational defects in omphacites from the CCSD-eclogites are mostly very rare. Occasionally, stacking faults parallel to (010), free dislocations with the Burgers vector [001] and those with 1/2[110] connected with antiphase domain boundaries (APBs), deformation twins on (100) and small-angle grain boundaries were observed. The explanation is that most CCSD-omphacites were strongly affected by recrystallisation, which took place above 600 °C during subduction up to its maximum temperature of ∼750 °C and continued during exhumation above 600 °C into the regime of amphibolite facies for several tens of Ma. Garnet shows very rarely crystal defects, while amphiboles usually displayed dislocations and chain multiplicity faults. Rutile of one sample, which contained a few percent Fe, showed fully coherent, nano-sized platelets (Guinier-Preston zones) parallel to (100) and (010). The existence of fluids during retrogression is documented by K-feldspar and analcime in quartz. © 2011 E. Schweizerbart'sche Verlagsbuchhandlung. Article 2011 English 09351221 10.1127/0935-1221/2011/0023-2133 European Journal of Mineralogy 23 Gebruder Borntraeger Verlagsbuchhandlung 645 – 659 4 China; Boreholes; Burgers vector; Crystal defects; Deformation; Feldspar; Garnets; Grain boundaries; High resolution transmission electron microscopy; Metamorphic rocks; Quartz; Titanium dioxide; Transmission electron microscopy; Twinning; Zeolites; Amphibole; Analcime; CCSD; Eclogites; Omphacite; Rutile; Chinese Continental Scientific Drilling Project; crystal structure; deformation mechanism; eclogite; jadeite; microstructure; omphacite; P-T conditions; P-T-t path; phase transition; recrystallization; temperature gradient; transmission electron microscopy; twinning; ultrahigh pressure metamorphism; Transmissions https://www.scopus.com/inward/record.uri?eid=2-s2.0-80054022142&doi=10.1127%2f0935-1221%2f2011%2f0023-2133&partnerID=40&md5=f07421d98754d80320e4a1abed03d511 Cited by: 5 Wolfgang Friedrich Müller Zhiqin Xu Frank E. Brenker article Burnett2011155 Forcing mechanisms of tropical climate in continental areas remain poorly understood, due in large part to a lack of continuous, long-term, high-fidelity records. Sediment core T97-52V from Lake Tanganyika provides new insight into the timing and mechanisms behind East African climate change over the past 90+. kyr. This record is particularly important, because, other than a recently recovered scientific drill core from Lake Malawi, there are no other continuous, well-dated records from East Africa prior to 60. ka. The high resolution age model presented here provides a large degree of age certainty for the past 45+. kyr, and our suite of proxies allows a thorough examination of Lake Tanganyika's dynamics. From core stratigraphy and chemical analyses, we present evidence of a lake level drop greater than 400. m sometime prior to ~. 90. ka, much greater than that inferred for the LGM, suggesting a period of intense aridity sometime around 100. ka. Additionally, core T97-52. V preserves evidence of worm burrows detected by X-radiographic imagery as indicated by burrow-shaped deposits of iron oxide, indicating a shallow lake at the time of deposition of that material. Intermittently high lake levels between ~. 78. ka and ~. 72. ka developed at the same time as a weakened Asian monsoon and a pluvial phase in Northeast Brazil, suggesting a global reorganization of climate, possibly forced by a reduction in orbital eccentricity. Over the past 60. ka this core preserves the same events recorded in a core collected ~. 100. km away in the southern basin of Lake Tanganyika, including an unexplained increase in biogenic silica at ~. 37. ka, suggesting that this vast lake is responding coherently across both major bathymetric basins to regional and global climate forcing. © 2010 Elsevier B.V. 2011 English 00310182 10.1016/j.palaeo.2010.02.011 Palaeogeography, Palaeoclimatology, Palaeoecology 303 155-167 Department of Earth Sciences, Syracuse University, New York 13244, United States; School of Geology and Geophysics, The University of Oklahoma, 100 East Boyd Street Suite 810, Norman, OK 73019, United States; Large Lakes Observatory, University of Minnesota, 2205 E. 5th St., Research Laboratory Building 207, Duluth, MN 55812, United States 1-4 biogenic deposit; climate change; intertropical convergence zone; lake level; Last Glacial Maximum; paleolimnology; proxy climate record; sediment core; tropical region; X-ray fluorescence, East Africa; East African Lakes; Lake Malawi; Lake Tanganyika https://www.scopus.com/inward/record.uri?eid=2-s2.0-79953152440&doi=10.1016%2fj.palaeo.2010.02.011&partnerID=40&md5=5adb7fca39e6c2f682566f76a2d7d82e cited By 96 A.P. Burnett M.J. Soreghan C.A. Scholz E.T. Brown article Kamo2011401 The U-Pb ages of shocked zircon crystals from the Chicxulub impact crater and Cretaceous-Paleogene (K-Pg) boundary sites in Haiti, the USA, and Canada, and the pattern of decreasing particle size with paleodistance from the crater, have been used as evidence of a genetic link between Chicxulub and the K-Pg boundary. Despite this, the inference that the K-Pg boundary layer formed as a direct consequence of the Chicxulub impact has been repeatedly questioned. Here we present U-Pb (ID-TIMS) ages and textural evidence of shock metamorphosed zircon grains from the K-Pg boundary at Caravaca, Spain, and Petriccio, Italy, that establish a causal connection between the impact and formation of the K-Pg boundary layer. The shocked zircon grains give data that produce a characteristic age pattern, which indicates a primary source age of 549.5 ± 5.7 Ma and a secondary event at the approximate time of impact at 66. Ma. The intensity of the shock features is proportional to the degree of isotopic resetting, and all textural features and ages are analytically identical to those of previously analyzed zircon from Chicxulub and K-Pg boundary sites in North America. Caravaca and Petriccio were > 8000 km from Chicxulub at the time of impact, and are therefore the farthest K-Pg sites identified that can be linked to Chicxulub through the dating of individual shocked zircon grains. We conclude that the combined age data and textural observations provide unambiguous evidence that ejecta from the Chicxulub impact formed the global K-Pg boundary layer. These data cannot be explained by the alternative scenario that the Chicxulub impact occurred ~. 300. ka prior to the K-Pg boundary. © 2011 Elsevier B.V.. 2011 10.1016/j.epsl.2011.08.031 Earth and Planetary Science Letters 310 401-408 Jack Satterly Geochronology Laboratory, Department of Geology, University of Toronto, 22 Russell St., Toronto, ON, Canada; Departamento de Geologia, Universidade Federal de Ouro Preto, Ouro Preto, Minas Gerais, 35400000, Brazil; Department of Earth Science and Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom 3-4 https://www.scopus.com/inward/record.uri?eid=2-s2.0-80053376976&doi=10.1016%2fj.epsl.2011.08.031&partnerID=40&md5=4d09016b104dfa478894ee09d6ff886a cited By 30 S.L. Kamo C. Lana J.V. Morgan article 2011 10.19800/j.cnki.aps.2011.03.006 Acta Palaeontolgica Sinica 50 330-343 3 S. Li D. Xi X. Jing Q. Huang Z. Wang X. Wan article Cichy20111469 Isothermal decompression experiments were performed to simulate magma ascent at Unzen volcano from the depths of magma storage to shallow crustal levels, corresponding to pressure decrease from 300 to 50 MPa. A partially crystallized synthetic rhyodacitic magma (representing equilibrium conditions at 850°C and 300 MPa) was used as a starting material; this has a composition identical to the groundmass of Unzen rocks erupted in 1991-1995. Decompression rates were varied from 0·0002 to 20 MPa s-1. Experiments conducted with decompression rates ≥0·1 MPa s-1 were decompressed continuously; a multi-step decompression approach was used at decompression rates ≤0·1 MPa s-1. The experiments were fluid-saturated, either containing only water as a fluid component (H2O-bearing) or containing a water and carbon dioxide mixture (H2O + CO2; initial mole fraction of H2O in the fluid ~0·6). The experimental products of the H2O-bearing experiments consist of amphibole, pyroxenes, oxides and glass. Plagioclase microlites nucleated and grew only in experiments with the two lowest decompression rates of 0·0005 and 0·0002 MPa s-1. The length of those plagioclases is up to 200-250 μm, which is consistent with the size of plagioclase microlites observed in the natural samples. The experimental products of the H2O + CO2-bearing system are composed of pyroxenes, oxides, glass and plagioclase. Plagioclase microlites in the H2O + CO2-system were already present in the starting assemblage and grew to a maximum size of ~80 μm. Equilibrium concentrations of water in the residual glasses at the final pressure of 50 MPa are reached at decompression rates ≤1 MPa s-1 for the H2O + CO2-bearing system and ≤0·1 MPa s-1 for the H2O-bearing system. The bubble number density (BND) values range from 103·7 to 105·6 mm-3 in the H2O-bearing system and from 104·6 to 106·4 mm-3 in the H2O + CO2-bearing systems. In both systems, BND values decrease with decreasing decompression rate from 20 to 0·01 MPa s-1, and increase with decreasing decompression rates &lt; 0·01 MPa s-1, which is interpreted to reflect predominant bubble growth and bubble nucleation, respectively. The onset of crystallization, observed from changes in the chemical composition of the residual melt, occurs at decompression rates &lt; 0·1 MPa s-1. At the lowest decompression rate (0·0002 MPa s-1) the chemical composition of the residual melt in the H2O + CO2-bearing system becomes similar to the natural matrix glass composition. There is no significant variation of the microlite number density (MND) value as a function of the decompression rate. The MND values for plagioclases-only range from 105·4 to 105·7 mm-3, whereas the MND values for the other phases range from 105·3 to 105·9 mm-3. Our experimental MNDPl values are in the range of those from natural samples (105-106 mm-3). We show that the size of microlites nucleating and crystallizing during decompression (plagioclase in our experimental dataset) is useful to constrain magma ascent rates at the onset of the crystallization of the corresponding phase. Based on the size of plagioclase microlites and on the composition of the residual melts, the average magma ascent rates of Unzen magmas in the pressure range 200 to 50 MPa is estimated to be 10-50 m h-1. © The Author 2010. Published by Oxford University Press. All rights reserved. 2011 English 00223530 10.1093/petrology/egq072 Journal of Petrology 52 Oxford University Press 1469-1492 Institut Für Mineralogie, Leibniz Universität Hannover, Callinstr. 3, D-30167 Hannover, Germany 7-8 amphibole; chemical composition; decompression; glass; magma; nucleation; oxide; plagioclase; pressure; pyroxene; volcanic rock, Japan; Kyushu; Nagasaki [Kyushu]; Unzen Volcano https://www.scopus.com/inward/record.uri?eid=2-s2.0-79961066913&doi=10.1093%2fpetrology%2fegq072&partnerID=40&md5=e894e4fc0ef97bbb8340310c7b5cd1f6 cited By 39 S.B. Cichy R.E. Botcharnikov F. Holtz H. Behrens article wu2011well 2011 Journal of Palaeogeography 13 103-110 XS Wu JJ Guo YJ Huang JW Fu article Rybacki2011107 The microstructures of four core samples from the San Andreas Fault Observatory at Depth (SAFOD) were investigated with optical and transmission electron microscopy. These samples, consisting of sandstone, siltstone, and fault gouge from phase III of the drilling campaign (3141-3307m MD), show a complex composition of quartz, feldspar, clays, and amorphous material. Microstructures indicate intense shearing and dissolution-precipitation as main deformation processes. The samples also contain abundant veins filled with calcite. Within the inspected veins the calcite grains exhibit different degrees of deformation with evidence for twinning and crystal plasticity. Dislocation densities (ranging from≈3·1012m-2 to ≈3·1013m-2) and twin line densities (≈22mm-1-165mm-1) are used as paleo-piezometers. The corresponding estimates of differential stresses vary between 33 and 132MPa, deduced from dislocation density and 92-251MPa obtained from twin density, possibly reflecting chronologically different maximum stress states and/or grain scale stress perturbations. Mean values of stress estimates are 68±46MPa and 168±60MPa, respectively, where estimates from dislocation density may represent a lower bound and those from twin density an upper bound. The stress estimates are also compatible with residual lattice strains determined with microfocus Laue diffraction yielding equivalent stresses of 50-300MPa in twinned calcite. The lower stress bound agrees with stress estimates from borehole breakout measurements performed in the pilot hole. From these data and assuming hydrostatic pore pressure and a low intermediate principal stress close to the overburden stress, frictional sliding of the San Andreas Fault at the SAFOD site is constrained to friction coefficients between 0.24 and 0.31. These low friction values may be related to the presence of clays, talc, and amorphous phases found in the fault cores and support the hypothesis of a weak San Andreas Fault. © 2011 Elsevier B.V. 2011 English 00401951 10.1016/j.tecto.2011.05.014 Tectonophysics 509 107-119 GFZ German Research Centre for Geosciences, Telegrafenberg, 14473 Potsdam, Germany; Department of Earth and Planetary Science, University of California, Berkeley, CA, United States 1-2 Amorphous phasis; Calcite grains; Calcite veins; Complex compositions; Crystal plasticity; Deformation process; Differential stress; Dislocation densities; Equivalent stress; Fault core; Fault gouge; Friction coefficients; Frictional sliding; Intermediate principal stress; Lattice strain; Laue diffraction; Line density; Low friction; Low temperature deformations; Lower bounds; Lower stress; Maximum stress; Mean values; Microstructural analysis; Overburden stress; Piezometer; Pilot holes; Residual strains; SAFOD; San Andreas Fault; Scale stress; Siltstones; Upper Bound, Amorphous materials; Calcite; Deformation; Dislocations (crystals); Dissolution; Elasticity; Estimation; Friction; Light transmission; Microstructure; Quartz; Strain; Structural geology; Transmission electron microscopy; Twinning, Carbonate minerals, borehole breakout; calcite; deformation mechanism; dissolution; fault gouge; low temperature; microstructure; precipitation (chemistry); pressure effect; San Andreas Fault; sandstone; siltstone; transmission electron microscopy; twinning, California; San Andreas; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-79961031875&doi=10.1016%2fj.tecto.2011.05.014&partnerID=40&md5=ef8b3a401288ed04c6737632c161e1af cited By 28 E. Rybacki C. Janssen R. Wirth K. Chen H.-R. Wenk D. Stromeyer G. Dresen article Taran2011219 Graphitic schists from the Outokumpu Deep Drill Hole were investigated in order to reconstruct the structure and composition of organic matter and stable isotope carbon and sulphur geochemistry of graphite, pyrite and pyrrhotite. Core samples of graphitic schists were collected from three depth levels of the Outokumpu Deep Drill Hole. The studied rocks were biotite-(tremolite-) graphite and, occasionally, muscovite (sericite)- and titanite-bearing schists and quartzitic schists. All samples were enriched in sulphides (mostly pyrite and pyrrhotite). Carbon isotope δ13C values of graphitic C were found to vary from -18.4 to -27.4‰. Graphitic schists from the middle part of the core in association with ophiolite-derived serpentinite and other altered ultramafic rocks showed more elevated δ13C values. This suggests incorporation of isotopically heavy carbon species during metamorphism, probably resulting from decarbonation reactions in carbonatebearing rocks. d34S values in the graphitic schists of the Outokumpu Deep Drill Hole were determined to be in range of -3.0 to -9.9‰ for pyrite and -3.8 to -10.8‰ for pyrrhotite. These concentrations could be explained by bacterial reduction of seawater sulphate and, to some extent, by the addition of hydrothermal sulphur. The predominance of aliphatic and oxygen-bearing groups in the bitumen structure suggests a sapropelic origin of the organic matter. Particularities in the distribution of Corganic and chemical changes in the bitumen composition along the core section could be interpreted as evidence of different sources and possibly the re-deposition of organic matter. Article 2011 English 978-952217152-8 07828535 Special Paper of the Geological Survey of Finland 2011 Kukkonen I.T. 219 – 228 51 Finland; Ita Suomen; Outokumpu; Bacteria (microorganisms); bitumen; borehole; carbon isotope; concentration (composition); geochemistry; graphite; isotopic analysis; metamorphism; metasedimentary rock; muscovite; organic carbon; organic matter; Proterozoic; schist; serpentinite; stable isotope; sulfide; ultramafic rock https://www.scopus.com/inward/record.uri?eid=2-s2.0-80051880869&partnerID=40&md5=a3dadf5ab721cdbc0655ad2f3aaf3caa Cited by: 8 Ludmila N. Taran Mariya P. Onoshko Nikolaj D. Mikhailov article Hauffe2011175 The quality of spatial analyses of biodiversity is improved by (i) utilizing study areas with well defined physiogeographical boundaries, (ii) limiting the impact of widespread species, and (iii) using taxa with heterogeneous distributions. These conditions are typically met by ecosystems such as oceanic islands or ancient lakes and their biota. While research on ancient lakes has contributed significantly to our understanding of evolutionary processes, statistically sound studies of spatial variation of extant biodiversity have been hampered by the frequently vast size of ancient lakes, their limited accessibility, and the lack of scientific infrastructure. The European ancient Lake Ohrid provides a rare opportunity for such a reliable spatial study. The comprehensive horizontal and vertical sampling of a species-rich taxon, the Gastropoda, presented here, revealed interesting patterns of biodiversity, which, in part, have not been shown before for other ancient lakes. In a total of 284 samples from 224 different locations throughout the Ohrid Basin, 68 gastropod species, with 50 of them (= 73.5%) being endemic, could be reported. The spatial distribution of these species shows the following characteristics: (i) within Lake Ohrid, the most frequent species are endemic taxa with a wide depth range, (ii) widespread species (i.e. those occurring throughout the Balkans or beyond) are rare and mainly occur in the upper layer of the lake, (iii) while the total number of species decreases with water depth, the proportion of endemics increases, and (iv) the deeper layers of Lake Ohrid appear to have a higher spatial homogeneity of biodiversity. Moreover, gastropod communities of Lake Ohrid and its feeder springs are both distinct from each other and from the surrounding waters. The analysis also shows that community similarity of Lake Ohrid is mainly driven by niche processes (e.g. environmental factors), but also by neutral processes (e.g. dispersal limitation and evolutionary histories of species). For niche-based mechanisms it is shown that large scale effects such as type of water body or water depth are mainly responsible for the similarity of gastropod communities, whereas small scale effects like environmental gradients affect gastropod compositions only marginally. In fact, neutral processes appear to be more important than the small scale environmental factors, thus emphasizing the importance of dispersal capacities and evolutionary histories of species. © Author(s) 2011. Article 2011 English 17264189 10.5194/bg-8-175-2011 Biogeosciences 8 175 – 188 1 Lake Ohrid; Gastropoda; endemic species; environmental factor; evolutionary biology; gastropod; heterogeneity; spatial analysis; spatial variation; species diversity; spring water; taxonomy; water depth https://www.scopus.com/inward/record.uri?eid=2-s2.0-79551501734&doi=10.5194%2fbg-8-175-2011&partnerID=40&md5=77cd42d7591f9bfe49cfcdb78a071d99 Cited by: 27; All Open Access, Gold Open Access, Green Open Access T. Hauffe C. Albrecht K. Schreiber K. Birkhofer S. Trajanovski T. Wilke article Sant2011987 Project Hotspot offers further understanding of the history and evolution of the Snake River Plain (SRP) through drilling wells in the SRP. The first well at Kimama encountered almost entirely basalt. Kimama drilled through a gradual transition from fresh to altered basalt with depth. The evolution of mineralization with depth at Kimama was initially calcite and some quartz followed by smectite clay minerals (nontronite and saponite) and zeolites. Smectite clay minerals are a great indicator of paleo-temperature of geothermal fluids. Description of the Kimama core, mineral habits, and forthcoming chemical analyses will be discussed in this paper. 2011 English 9781618394828 01935933 Transactions - Geothermal Resources Council 35 2 987-989 Utah State University, Logan, UT, United States Geothermal; Geothermometers; Hot spot; Kimama; Snake river plains, Basalt; Calcite; Carbonate minerals; Chemical analysis; Clay; Drilling; Geothermal fields; Geothermal prospecting; Mineralogy; Quartz; Rivers, Clay minerals https://www.scopus.com/inward/record.uri?eid=2-s2.0-84860874752&partnerID=40&md5=4c1375940814f3e072b0c614de546e39 cited By 3 C.J. Sant J.W. Shervais article Zoback201114 The San Andreas Fault Observatory at Depth (SAFOD) was drilled to study the physical and chemical processes controlling faulting and earthquake generation along an active, plate-bounding fault at depth. SAFOD is located near Parkfield, California and penetrates a section of the fault that is moving due to a combination of repeating microearthquakes and fault creep. Geophysical logs define the San Andreas Fault Zone to be relatively broad (~200 m), containing several discrete zones only 2-3 m wide that exhibit very low P- and S-wave velocities and low resistivity. Two of these zones have progressively deformed the cemented casing at measured depths of 3192 m and 3302 m. Cores from both deforming zones contain a pervasively sheared, cohesionless, foliated fault gouge that coincides with casing deformation and explains the observed extremely low seismic velocities and resistivity. These cores are being now extensively tested in laboratories around the world, and their composition, deformation mechanisms, physical properties, and rheological behavior are studied. Downhole measurements show that within 200 m (maximum) of the active fault trace, the direction of maximum horizontal stress remains at a high angle to the San Andreas Fault, consistent with other measurements. The results from the SAFOD Main Hole, together with the stress state determined in the Pilot Hole, are consistent with a strong crust/weak fault model of the San Andreas. Seismic instrumentation has been deployed to study physics of faulting-earthquake nucleation, propagation, and arrest-in order to test how laboratory-derived concepts scale up to earthquakes occurring in nature. 2011 English 18168957 10.2204/iodp.sd.11.02.2011 Scientific Drilling 14-28 Department of Geophysics, Stanford University, Stanford, CA 94305-2215, United States; U.S. Geological Survery, 345 Middlefield Road, MS 977, Menlo Park, CA 94025-3591, United States 1 Active fault; Bounding faults; California; Casing deformation; Chemical process; Deformation mechanism; Deforming zone; Downhole measurements; Earthquake nucleation; Fault creep; Fault gouge; Fault model; Geophysical logs; Horizontal stress; Low resistivity; Measured depths; Micro-earthquakes; Pilot holes; Rheological behaviors; S-wave velocity; San Andreas Fault; Scale-up; Scientific drilling; Seismic instrumentation; Seismic velocities; Stress state, Deformation; Earthquakes; Parks; Rheology; Structural geology, Tectonics https://www.scopus.com/inward/record.uri?eid=2-s2.0-79955161589&doi=10.2204%2fiodp.sd.11.02.2011&partnerID=40&md5=7b65d928eefa85d49e2ad2bdb555b94c cited By 131 M. Zoback S. Hickman W. Ellsworth article Wolff2011743 Interannual rainfall variations in equatorial East Africa are tightly linked to the El Niño Southern Oscillation (ENSO), with more rain and flooding during El Niño and droughts in La Niña years, both having severe impacts on human habitation and food security. Here we report evidence from an annually laminated lake sediment record from southeastern Kenya for interannual to centennial-scale changes in ENSO-related rainfall variability during the last three millennia and for reductions in both the mean rate and the variability of rainfall in East Africa during the Last Glacial period. Climate model simulations support forward extrapolation from these lake sediment data that future warming will intensify the interannual variability of East Africa's rainfall. 2011 English 00368075 10.1126/science.1203724 Science 333 743-747 Helmholtz Centre Potsdam GeoForschungsZentrum (GFZ-German Research Centre for Geosciences), Climate Dynamics and Landscape Evolution, Telegrafenberg, D-14473 Potsdam, Germany; Deutsche Forschungsgemeinschaft (DFG) Graduate School 1364, University of Potsdam, Institute of Geosciences, Karl-Liebknecht Strasse 24, D-14476 Potsdam, Germany; DFG Leibniz Center for Earth Surface Process and Climate Studies, University of Potsdam, D-14476 Potsdam, Germany; Geological Institute, Department of Earth Sciences, Eidgenössische Technische Hochschule (ETH-Swiss Federal Institute of Technology), Zürich, CH-8092 Zurich, Switzerland; International Pacific Research Center, School of Ocean and Earth Science and Technology, University of Hawai'i, 2525 Correa Road, HI 96822, United States; Faculty of Geosciences, Utrecht University, Post Office Box 80021, 3508 TA Utrecht, Netherlands; Department of Marine Organic Biogeochemistry, Nederlands Instituut Voor Zeeonderzoek (NIOZ-Royal Netherlands Institute for Sea Research), Post Office Box 59, 1790 AB Den Burg, Netherlands; Department of Geosciences, Princeton University, Princeton, NJ 08544, United States; Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY 10964-8000, United States; Limnology Unit, Department of Biology, Ghent University, Ledeganckstraat 35, 9000 Gent, Belgium 6043 rain, annual variation; climate modeling; El Nino-Southern Oscillation; flooding; food security; lacustrine deposit; paleoclimate; Pleistocene; precipitation intensity, Africa; article; climate; El Nino; food security; glacial period; lake sediment; priority journal; seasonal variation, Kenya https://www.scopus.com/inward/record.uri?eid=2-s2.0-79961241131&doi=10.1126%2fscience.1203724&partnerID=40&md5=40813f4a44e1a848cdb32d6826fa5956 cited By 130 C. Wolff G.H. Haug A. Timmermann J.S. Sinninghe Damsté A. Brauer D.M. Sigman M.A. Cane D. Verschuren article Weis2011831 Linear chains of volcanic ocean islands are one of the most distinctive features on our planet. The longest, the Hawaiiang-Emperor Chain, has been active for more than 80 million years, and is thought to have formed as the Pacific Plate moved across the Hawaiian mantle plume, the hottest and most productive of Earth's plumes. Volcanoes fed by the plume today form two adjacent trends, including Mauna Kea and Mauna Loa, that exhibit strikingly different geochemical characteristics. An extensive data set of isotopic analyses shows that lavas with these distinct characteristics have erupted in parallel along the Kea and Loa trends for at least 5 million years. Seismological data suggest that the Hawaiian mantle plume, when projected into the deep mantle, overlies the boundary between typical Pacific lower mantle and a sharply defined layer of apparently different material. This layer exhibits low seismic shear velocities and occurs on the Loa side of the plume. We conclude that the geochemical differences between the Kea and Loa trends reflect preferential sampling of these two distinct sources of deep mantle material. Similar indications of preferential sampling at the limit of a large anomalous low-velocity zone are found in Kerguelen and Tristan da Cunha basalts in the Indian and Atlantic oceans, respectively. We infer that the anomalous low-velocity zones at the core-mantle boundary are storing geochemical anomalies that are enriched in recycled material and sampled by strong mantle plumes. © 2011 Macmillan Publishers Limited. All rights reserved. 2011 English 17520894 10.1038/ngeo1328 Nature Geoscience 4 831-838 Department of Earth and Ocean Sciences, University of British Columbia, 6339 Stores Road, Vancouver, BC V6T1Z4, Canada; Pacific Centre for Isotopic and Geochemical Research, University of British Columbia, 6339 Stores Road, Vancouver, BC V6T1Z4, Canada; Department of Geology and Geophysics, University of Hawai'i, Honolulu, HI 96822, United States; Department of Geosciences, University of Massachusetts, Amherst, MA 01003, United States 12 asymmetry; data set; geochemical survey; isotopic analysis; mantle plume; Pacific plate; sampling; seismic velocity; volcanic island, Atlantic Ocean; French Southern Territories; Hawaiian Islands; Indian Ocean; Kerguelen; Kerguelen Islands https://www.scopus.com/inward/record.uri?eid=2-s2.0-82455210623&doi=10.1038%2fngeo1328&partnerID=40&md5=eee05ee94f6c1cccd03e46bee9b9711f cited By 180 D. Weis M.O. Garcia J.M. Rhodes M. Jellinek J.S. Scoates article Weymer201148 2011 English 18168957 10.5194/sd-11-48-2011 Scientific Drilling Copernicus GmbH 48-50 Integrated Ocean Drilling Program and SAFOD, Texas A and M University, 1000 Discovery Drive, College Station, TX 77845-9547, United States; Department of Geology and Geophysics, TAMU, Center for Tectonophysics and Department of Geology and Geophysics, Texas A and M University, College Station, TX 77843-3115, United States; Geological Survey Earthquake Science Center, 345 Middlefield Road, MS/977Menlo Park, CA 94025, United States 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-79955129704&doi=10.5194%2fsd-11-48-2011&partnerID=40&md5=68ce30304ca45d0df6257e65dbdbeee8 cited By 0 B. Weymer J. Firth P. Rumford F. Chester J. Chester D. Lockner article Liu20111693 Long-chain alkenones in lacustrine settings are potentially excellent biomarkers for the reconstruction of past terrestrial environmental conditions, and have been found in many different types of lakes around the globe. A wider range of factors influence the occurrence and distribution of alkenones in lake sediments and waters when compared to marine systems. Lake environmental conditions, such as temperature (in particular) and salinity, are among the key factors controlling alkenone distributions in lacustrine settings. Here we investigated alkenone distribution patterns in lakes of the northern Qinghai-Tibetan Plateau, China, and their possible relationship with environmental conditions, by analyzing paired samples of suspended particulate matter in surface waters and surface sediments. Salinity of investigated lake waters ranges from almost 0 to ∼100g/L, while temperature variation among the lakes is minimal, effectively eliminating temperature effects on the alkenone distribution patterns observed here. We show that (1) alkenone concentrations vary substantially between the lakes, yet controlling mechanisms remain elusive; (2) C37/C38 ratios are substantially lower in the lakes of the Qaidam Basin than in the Lake Qinghai region, probably indicating different alkenone producers in the two regions; and (3) large variations in %C37:4 (the percentage of the C37:4 alkenone), determined from both surface waters and sediments, are negatively correlated with salinity. We suggest that the %C37:4 index could be used as a salinity indicator at least on a regional scale, with careful considerations of other potentially complicating factors. However, potential reasons for why salinity could significantly affect %C37:4 values need further investigation. © 2011 Elsevier Ltd. Article 2011 English 00167037 10.1016/j.gca.2010.10.029 Geochimica et Cosmochimica Acta 75 Elsevier Ltd 1693 – 1703 7 China; Qaidam Basin; Qinghai; Qinghai-Xizang Plateau; alkenone; biomarker; concentration (composition); isotopic ratio; lacustrine deposit; lake water; paleoenvironment; salinity; suspended particulate matter; water temperature https://www.scopus.com/inward/record.uri?eid=2-s2.0-79952444657&doi=10.1016%2fj.gca.2010.10.029&partnerID=40&md5=96d7af4ad497d09cb99949198e065b7c Cited by: 66 Weiguo Liu Zhonghui Liu Huanye Wang Yuxin He Zheng Wang Liming Xu article Lorenschat2011113 2011 English 15629449 Joannea - Geologie und Palaontologie 113-115 Institut für Umweltgeologie, Technische Universität Braunschweig, Langer Kamp 19c, 38106 Braunschweig, Germany; Macedonian Museum of Natural History, Boulevard Ilinden 86, MK-1000 Skopje, North Macedonia; Institut für Geologie und Mineralogie, Universität zu Köln, Zülpicherstraße 49 a/b, 50674 Köln, Germany 11 ecosystem approach; fossil record; genetic analysis; molecular analysis; ostracod; paleoenvironment; science and technology; speciation (biology), Lake Ohrid, Ostracoda https://www.scopus.com/inward/record.uri?eid=2-s2.0-80053257183&partnerID=40&md5=619f0af3beec1590e2cc19698b0f3ce3 cited By 2 J. Lorenschat B. Scharf T. Petkovski F. Viehberg A. Schwalb article Scholz20113 The recovery of detailed and continuous paleoclimate records from the interior of the African continent has long been of interest for understanding climate dynamics of the tropics, and also for constraining the environmental backdrop to the evolution and spread of early Homo sapiens. In 2005 an international team of scientists collected a series of scientific drill cores from Lake Malawi, the first long and continuous, high-fidelity records of tropical climate change from interior East Africa. The paleoclimate records, which include lithostratigraphic, geochemical, geophysical and paleobiological observations documented in this special issue of Palaeo3, indicate an interval of high-amplitude climate variability between 145,000 and ~60,000years ago, when several severe arid intervals reduced Lake Malawi's volume by more than 95%. These intervals of pronounced tropical African aridity in the early Late Pleistocene around Lake Malawi were much more severe than the Last Glacial Maximum (LGM), a well-documented period of drought in equatorial and Northern Hemisphere tropical east Africa. After 70,000years ago climate shifted to more humid conditions and lake levels rose. During this latter interval however, wind patterns shifted rapidly, and perhaps synchronously with high-latitude shifts and changes in thermohaline circulation. This transition to wetter, more stable conditions coincided with diminished orbital eccentricity, and a reduction in precession-dominated climatic extremes. The observed climate mode switch to decreased environmental variability is consistent with terrestrial and marine records from in and around tropical Africa. © 2010 Elsevier B.V. 2011 English 00310182 10.1016/j.palaeo.2010.10.030 Palaeogeography, Palaeoclimatology, Palaeoecology 303 3-19 Department of Earth Sciences, Syracuse University, Syracuse NY, 13244, United States; Department of Geosciences, University of Arizona, Tucson, AZ 85721, United States; Large Lakes Observatory and Department of Geological Sciences, University of Minnesota Duluth, Duluth, MN 55812, United States; Graduate School of Oceanography, University of Rhode Island, Narragansett, RI 02882, United States; Department of Earth Science, University of Bergen, N-5007 Bergen, Norway 1-4 climate variation; lake level; Last Glacial Maximum; marine record; paleobiology; paleoclimate; rift zone; Southern Hemisphere; thermohaline circulation; tropical region, East African Lakes; Kenya; Lake Malawi; Rift Valley, Homo sapiens https://www.scopus.com/inward/record.uri?eid=2-s2.0-79953164615&doi=10.1016%2fj.palaeo.2010.10.030&partnerID=40&md5=3514d04173bb8c399f7b33863f0d9ced cited By 76 C.A. Scholz A.S. Cohen T.C. Johnson J. King M.R. Talbot E.T. Brown article Jin2011 River waters collected weekly over the whole year of 2007 from the Buha River draining to Lake Qinghai on the northeastern Tibetan Plateau were analyzed for major ions and Sr isotopes. Dissolved loads in the river exhibit distinct seasonal variability in major cation ratios and Sr isotopes over the 1 year period, reflecting seasonal differences in relative inputs from various sources and weathering reactions in the catchment. Distinct geochemical signatures suggest that eolian dust may affect river water chemistry significantly, resulting in a twofold increase influx of dissolved loads during spring relative to winter. It is noticeable that both the lowest and the highest 87Sr/86Sr values of the Buha River waters occurred in the monsoon season, indicating a sensitive response of carbonate versus silicate weathering sources to hydrological forcing on a seasonal basis. A significant decrease in Na/cation, together with lower Sr isotope ratios, is consistent with a greater proportion f carbonate weathering relative to silicate weathering in the early monsoon season. High temperature and increased rainfall during the peak of the monsoon facilitate an increased proportion of ions derived from silicates, partly from groundwaters, to river water. In other seasons, elemental and 87Sr/86Sr ratios vary much less, indicating a constant ratio of silicate to carbonate weathering, consistent with limited variation in discharge. Our results highlight that in a semiarid region where climatic conditions vary seasonally, in addition to silicate and carbonate contributions, supply from eolian dust may also play a significant role in controlling seasonal variations in chemistry of river waters. Copyright 2011 by the American Geophysical Union. Article 2011 English 21699011 10.1029/2011JF002002 Journal of Geophysical Research: Earth Surface 116 Blackwell Publishing Ltd 4 Buha River; China; Qinghai; Qinghai-Xizang Plateau; carbonate; catchment; groundwater; high temperature; monsoon; rainfall; river water; seasonal variation; strontium isotope; water chemistry; weathering https://www.scopus.com/inward/record.uri?eid=2-s2.0-80155130056&doi=10.1029%2f2011JF002002&partnerID=40&md5=a8dc1c26243de5615a29c76a06601b9c Cited by: 56; All Open Access, Bronze Open Access Zhangdong Jin Chen-Feng You Jimin Yu Lingling Wu Fei Zhang Hou-Chun Liu article Tomonaga20112848 In this study, the largest ever carried out to measure noble gases in the pore water of unconsolidated sediments in lakes, the emission of terrigenic He through the sediment column of Lake Van was successfully mapped on the local scale. The main input of He to the water body occurs at the borders of a deep basin within the lake, which is probably the remains of a collapsed caldera. The 3He/4He ratio identifies the He injected into the sedimentary column of Lake Van as a mixture of He released from a mantle source and radiogenic He of crustal origin (3He/4He~2.6-4.1×10-6). During passage through the pore space, terrigenic He seems to be further enriched in radiogenic He that is most likely produced in the sediment column. In fact, two distinct trends in isotopic composition can be distinguished in the He injected from the lake basement into the sediments. One of these characterizes samples from the shallow water, the other characterizes samples from the deep basin. However, both of these trends are related to the same source of terrigenic He. The He fluxes determined seem to be characteristic of each sampling location and might be considered as a proxy for the fluid permeability of the deep sediment column. These new findings provide insight into the process of fluid transport within the sediments and into the process of formation of the lake basin. Moreover, the isotopic signature of the He that emanates into the water column of Lake Van is strongly affected by the mixing conditions prevailing in the overlying water body. This fact misled previous studies to interpret the terrigenic He in Lake Van as being solely of mantle origin (3He/4He~10-5). © 2011 Elsevier Ltd. 2011 English 00167037 10.1016/j.gca.2011.02.038 Geochimica et Cosmochimica Acta 75 2848-2864 Eawag, Swiss Federal Institute of Aquatic Science and Technology, CH-8600 Dübendorf, Switzerland; Institute of Biogeochemistry and Pollutant Dynamics, Swiss Federal Institute of Technology (ETH), CH-8092 Zurich, Switzerland; Institute of Geochemistry and Mineral Resources, Swiss Federal Institute of Technology (ETH), CH-8092 Zurich, Switzerland 10 basin evolution; deep-sea sediment; helium; isotopic composition; lacustrine deposit; lake water; mantle source; noble gas; permeability; porewater; sediment chemistry; sedimentary structure; spatial distribution, Lake Van; Turkey https://www.scopus.com/inward/record.uri?eid=2-s2.0-79955089402&doi=10.1016%2fj.gca.2011.02.038&partnerID=40&md5=702d9816c76729c35b61ebd10b6a5793 cited By 26 Y. Tomonaga M.S. Brennwald R. Kipfer article Mormone2011385 The distribution of the alteration assemblages and the related physico-chemical changes induced in the rocks with depth, may provide useful information on the state of the system. Drillholes are the only way to define hydrothermal alteration depth-profiles in variable geological contexts. Deep drillings exploiting programs were conducted since the 1970's by the Agip-Enel Joint Venture in the Quaternary Campi Flegrei caldera (southern Italy), where a geothermal system has been active since at least historical times. New macroscopic and microscopic investigations were performed on selected samples made available by Agip in order to: 1) define the precursor lithology, 2) describe the relationships among texture, mineralogy and depth of the studied core samples and 3) examine the character of the secondary minerals and their distribution with depth and temperature. The new data are integrated with physical properties and elastic parameters of cored rocks, as well as structural information and field data, all available from the physical, seismological, geodetical and volcanological literature. The depth-related multi-parameters profiles provide evidence on the different behavior of the buried rocks beneath the Licola 1, Mofete and San Vito 1 areas, sited in three structurally different sectors of the caldera. The features of the hydrothermally altered rocks are a key to interpret the heterogeneities of the Campi Flegrei substratum, as deduced by velocity, attenuation and scattering P- and S- waves tomography. The time and space distribution of both the eruptive vents and the extruded magma volumes are consistent with the results of our analysis. Therefore, we interpret the observed Campi Flegrei geothermal system as a response to the distribution of volcanic activity in two structurally distinct sectors of the caldera. The central-eastern sector, where the San Vito 1 well was drilled, represents the preferential pathways for both gas escape and magma ascent at least since 8 kyrs, in contrast with the other sites of the caldera where eruptions occurred with minor frequency and magnitude. 2011 English 03698963 10.2451/2011PM0027 Periodico di Mineralogia 80 Sapienza Universita Editrice 385-406 Istituto Nazionale di Geofisica e Vulcanologia, Sezione Osservatorio Vesuviano, Napoli, Italy; Dipartimento di Scienze della Terra, Università Degli Studi di Napoli Federico II, Via Mezzocannone 8, 80134 Napoli, Italy 3 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84855852091&doi=10.2451%2f2011PM0027&partnerID=40&md5=83189c0c483030eb78489a94ad6d4e97 cited By 16 A. Mormone A. Tramelli M.A. Di Vito M. Piochi C. Troise G.D. Natale article Korte2011 For much of the Mesozoic record there has been an inconclusive debate on the possible global significance of isotopic proxies for environmental change and of sequence stratigraphic depositional sequences. We present a carbon and oxygen isotope and elemental record for part of the Early Jurassic based on marine benthic and nektobenthic molluscs and brachiopods from the shallow marine succession of the Cleveland Basin, UK. The invertebrate isotope record is supplemented with carbon isotope data from fossil wood, which samples atmospheric carbon. New data elucidate two major global carbon isotope events, a negative excursion of ∼2‰ at the Sinemurian-Pliensbachian boundary, and a positive excursion of ∼2‰ in the Late Pliensbachian. The Sinemurian-Pliensbachian boundary event is similar to the slightly younger Toarcian Oceanic Anoxic Event and is characterized by deposition of relatively deepwater organic-rich shale. The Late Pliensbachian strata by contrast are characterized by shallow marine deposition. Oxygen isotope data imply cooling locally for both events. However, because deeper water conditions characterize the Sinemurian-Pliensbachian boundary in the Cleveland Basin the temperature drop is likely of local significance; in contrast a cool Late Pliensbachian shallow seafloor agrees with previous inference of partial icehouse conditions. Both the large-scale, long-term and small-scale, short-duration isotopic cycles occurred in concert with relative sea level changes documented previously from sequence stratigraphy. Isotope events and the sea level cycles are concluded to reflect processes of global significance, supporting the idea of an Early Jurassic in which cyclic swings from icehouse to greenhouse and super greenhouse conditions occurred at timescales from 1 to 10 Ma. Copyright 2011 by the American Geophysical Union. Article 2011 English 08838305 10.1029/2011PA002160 Paleoceanography 26 Blackwell Publishing Ltd 4 Cleveland Basin; England; North Yorkshire; United Kingdom; anoxic conditions; benthos; biostratigraphy; brachiopod; carbon isotope; depositional sequence; environmental change; fossil record; glaciation; greenhouse effect; nekton; oxygen isotope; paleoceanography; paleoenvironment; Pliensbachian; sea level change; seafloor; sequence stratigraphy; Sinemurian https://www.scopus.com/inward/record.uri?eid=2-s2.0-84055197806&doi=10.1029%2f2011PA002160&partnerID=40&md5=52e23d1862232bcc1e811cb1b2fe9a34 Cited by: 176; All Open Access, Bronze Open Access Christoph Korte Stephen P. Hesselbo article Bartosova2011621 The Chesapeake Bay impact structure, approximately 85km in diameter, has been drilled in 2005-2006 at Eyreville (Virginia, USA), to a total depth of 1766m. In the drill cores, the abundance of shock metamorphosed material is very variable with depth. Shocked mineral and lithic clasts, as well as melt particles, are most abundant in suevitic impact breccia section (1397-1451m depth). Shocked quartz (i.e., quartz grains with planar fractures and/or planar deformation features) and melt particles, although rare, are also dispersed in the Exmore Formation unit (444-867m depth). Other lithologies in the Eyreville drill cores show no clear evidence of shock metamorphism. Here, we report on the investigations of 40 samples from the impact breccia section. A total of more than 27,000 quartz grains were examined in about 200 clasts. The abundance of highly shocked clasts tends to decrease with increasing depth. Crystalline clasts derived from the crystalline basement are commonly only slightly shocked (contain generally <10rel% of shocked quartz grains). The clasts of metamorphosed sediments show a low proportion of shocked quartz grains (mostly <10rel%). Sedimentary clasts show a wide range of proportions of shocked quartz grains, with several of them being highly shocked clasts (most values between 0 and 40rel%). Conglomerates show the highest proportion of shocked quartz grains of all types of clasts (up to 83rel%). Polycrystalline quartz clasts are also commonly highly shocked (contain mostly between 10 and 40rel% of shocked quartz grains). These hard nonporous clasts are possibly more liable to show evidence of shock. The investigations suggest that the intensity of shock metamorphism is the result of several parameters, such as original position in the target (both horizontal and vertical) and the properties of each lithology (e.g., grain size, porosity, and amount of matrix). According to the universal-stage investigations, the dominant orientations of planar deformation features in quartz are {101̄3}, {101̄2}, and also {101̄4}. © The Meteoritical Society, 2011. 2011 English 10869379 10.1111/j.1945-5100.2011.01179.x Meteoritics and Planetary Science 46 621-637 Department of Lithospheric Research, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria; Natural History Museum, Burgring 7, A-1010 Vienna, Austria 5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-79955743565&doi=10.1111%2fj.1945-5100.2011.01179.x&partnerID=40&md5=8adf7e9486fc4e4b179052f931517c54 cited By 1 K. Bartosova C. Koeberl article Gupta20115 Earthquake activity is monitored in real time at the Koyna reservoir in western India, beginning from August 2005 and successful short term forecasts have been made of M ∼ 4 earthquakes. The basis of these forecasts is the observation of nucleation that precedes such earthquakes. Here we report that a total of 29 earthquakes in the magnitude range of 3.5 to 5.1 occurred in the region during the period of August 2005 through May 2010. These earthquakes could broadly be put in three zones. Zone-A has been most active accounting for 18 earthquakes, while 5 earthquakes in Zone-B and 6 in Zone-C have occurred. Earthquakes in Zone-A are preceded by well defined nucleation, while it is not the case with zones B and C. This indicates the complexity of the earthquakes processes and the fact that even in a small seismically active area of only 20 km × 30 km earthquake forecast is difficult. © 2011 Geological Society of India. 2011 English 00167622 10.1007/s12594-011-0001-z Journal of the Geological Society of India 77 5-11 National Geophysical Research Institute (CSIR), Uppal Road, Hyderabad 500 007, India 1 earthquake magnitude; earthquake prediction; nucleation; observational method; seismic zone, India; Koyna; Maharashtra https://www.scopus.com/inward/record.uri?eid=2-s2.0-79952608176&doi=10.1007%2fs12594-011-0001-z&partnerID=40&md5=9f8c97e25c3c441f9486e6e8d16caf3d cited By 21 H. Gupta D. Shashidhar K. Mallika N.P. Rao D. Srinagesh H.V.S. Satyanarayana S. Saha R.T.B. Naik article Alsop2011433 The Late Pleistocene Lisan Formation preserved next to the Dead Sea provides exceptional 3-D exposures of folds and faults generated during soft-sediment slumping and deformation. It is possible to generate a range of four different scenarios associated with overprinting in a single slump event. The progressive evolution of slump systems may be broadly categorised into initiation, translation, cessation, relaxation and compaction phases. Thrust packages typically define piggyback sequences during slump translation, with back-steepening of imbricate faults leading to collapse of folds back up the regional palaeoslope. Detailed evaluation of slumped horizons may also permit structures to be traced across apparently separate and distinct slumped units. The recognition that slumps may be reworked by younger seismically-triggered events suggests that in some cases the seismic recurrence interval may be shorter than previously anticipated. © 2011 Elsevier Ltd. 2011 English 01918141 10.1016/j.jsg.2011.02.003 Journal of Structural Geology 33 433-457 Department of Geology and Petroleum Geology, School of Geosciences, University of Aberdeen, Aberdeen AB24 3UE, United Kingdom; Department of Geophysics and Planetary Sciences, Tel Aviv University, Tel Aviv 69978, Israel 4 Dead Sea; Folds; Gravity-driven deformation; Mass transport complexes; Slump, Anoxic sediments; Deformation; Earthquakes; Mass transfer; Sedimentology, Gravitation, deformation; earthquake; fold; mass transport; slumping, Dead Sea https://www.scopus.com/inward/record.uri?eid=2-s2.0-79953024983&doi=10.1016%2fj.jsg.2011.02.003&partnerID=40&md5=2964740a02587761a42ac8df4619fb76 cited By 140 G.I. Alsop S. Marco article Vetere2011251 The solubility of H2O-CO2-bearing fluids in shoshonitic melts relevant to magmas of the Vulcanello peninsula and to mafic melts from magmas erupted at Campi Flegrei (Italy) was experimentally determined at pressures from 50 to 400MPa and at temperature of 1250°C. No quench crystals and less than 1vol.% bubles were observed in the rapid quenched glasses. H2O and CO2 contents in the experimental glasses were determined via Karl-Fischer Titration (KFT) and FTIR spectroscopy. For the quantification of volatile concentrations by IR spectroscopy we have calibrated the absorption coefficients of water-related and carbon-related IR bands for the shoshonitic composition. The determined absorption coefficients are 0.80±0.06L mol-1 cm-1 for the band at ~4500cm-1 (OH groups) and 1.02±0.03L mol-1 cm-1 for the band at ~5200cm-1 (H2O molecules). CO2 is bound in the shoshonitic glass as CO32- exclusively; its concentration was quantified by the peak height of the low wavenumber band of the doublet near 1430cm-1 using the calibrated absorption coefficient of 356±18L mol-1 cm-1.The H2O solubility in the shoshonitic melts is in the same range as observed for other natural aluminosilicate melts, i.e. 5.12±0.07wt.% at 200MPa and 7.92±0.07wt.% H2O at 400MPa. A non-linear variation of the H2O and CO2 solubility in the melts with increasing mole fraction of H2O (and thus decreasing mole fraction of CO2) in the fluid was observed at each investigated pressure. At 1250°C, the concentration of dissolved carbonate (expressed as CO2 component) in melts coexisting with nearly pure CO2 fluid increases from 307 to 2932ppm (±10% relative) as the pressure increases from 50 to 400MPa. The comparison of the dataset with available models predicting the H2O and CO2 concentrations in silicate melts coexisting with H2O-CO2-bearing fluids shows that the effect of melt composition is not calibrated appropriately in the models.The experimental data are used to re-evaluate the typical pressures of glass inclusions entrapment in phenocrysts from Minopoli2 eruption and the results indicate that the main magma chamber may have been located at a depth of ~ 4000 m. © 2011 Elsevier B.V. Article 2011 English 03770273 10.1016/j.jvolgeores.2011.03.002 Journal of Volcanology and Geothermal Research 202 251 – 261 3-4 Campania [Italy]; Campi Flegrei; Italy; Lipari Islands; Messina [Sicily]; Napoli [Campania]; Sicily; Vulcano; Aluminosilicates; Bearings (structural); Crystals; Fluids; Fourier transform infrared spectroscopy; Glass; Solubility; Water absorption; Campi Flegrei; ; O; Shoshonitic magmas; Vulcanello; absorption coefficient; carbon dioxide; FTIR spectroscopy; mafic rock; magma; magma chamber; magmatism; phenocryst; shoshonite; silicate melt; solubility; volcanic eruption; volcanic glass; Absorption spectroscopy https://www.scopus.com/inward/record.uri?eid=2-s2.0-79955038579&doi=10.1016%2fj.jvolgeores.2011.03.002&partnerID=40&md5=c3a4f0e0f1b9a1e444d90128c3188d77 Cited by: 42 Francesco Vetere Roman E. Botcharnikov François Holtz Harald Behrens Rosanna De Rosa article Scholz20111 2011 English 00310182 10.1016/j.palaeo.2011.01.001 Palaeogeography, Palaeoclimatology, Palaeoecology 303 1-2 Department of Earth Sciences, Syracuse University, Syracuse, NY 13244, United States; Department of Geosciences, University of Arizona, Tucson, AZ 85721, United States; Large Lakes Observatory and Department of Geological Sciences, University of Minnesota Duluth, Duluth, MN 55812, United States 1-4 https://www.scopus.com/inward/record.uri?eid=2-s2.0-79953163231&doi=10.1016%2fj.palaeo.2011.01.001&partnerID=40&md5=5ddd855e479b9bef7d3408fd20086ed9 cited By 4 C.A. Scholz A.S. Cohen T.C. Johnson article Dietze2011109 This study presents rock magnetic properties along with magnetic field measurements of different stratigraphic and lithologic basalt units from Reykjanes, the southwestern promontory of the Reykjanes peninsula, where the submarine Reykjanes Ridge passes over into the rift zone of southwestern Iceland. The basaltic fissure eruptions and shield lava of tholeiitic composition (less than 11500 a old) show a high natural remanent magnetization (NRM, Jr) up to 33.6 A/m and high Koenigsberger ratio (Q) up to 52.2 indicating a clear dominance of the NRM compared to the induced part of the magnetization. Pillow basalts and picritic shield lava show distinctly lower Jr values below 10 A/m. Magnetic susceptibility (κ) ranges for all lithologies from 2.5 to 26 × 10-3 SI. Heterogeneously distributed titanomagnetite with small grain sizes is the main carrier of magnetization. Magnetic susceptibility vs. temperature (κ-T) curves reveal multiple Curie temperatures from 35 to 570 °C suggesting different Ti-concentrations in titanomagnetite. A minor oxidation to titanomaghemite is indicated by the irreversibility of some of the κ-T curves. Intra flow variation of the magnetic minerals is relatively high depending on crystallization history and resulting primary composition and amount of titanomagnetite as well as high-temperature oxidation. The total geomagnetic field was measured for regional field variations along three profiles normal to the spreading zone at Reykjanes. These measurements along with the rock magnetic data and field observations were used for modeling the geological subsurface. The models are in agreement with a feeder dyke system related to the youngest Stampahraun 4 fissure eruption in the western part and a hydrothermally active fault system in the eastern part of Reykjanes. Furthermore, topographic features like fault scarps, pillow basalt - hyaloclastite ridges and shield lava are considered. © 2011 Institute of Geophysics of the ASCR, v.v.i. 2011 English 00393169 10.1007/s11200-011-0007-4 Studia Geophysica et Geodaetica 55 Kluwer Academic Publishers 109-130 Institut für Angewandte Geowissenschaften, Karlsruher Institut für Technologie (KIT), Hertzstr. 16, D-76187 Karlsruhe, Germany; Bundesanstalt für Geowissenschaften und Rohstoffe, Stilleweg 2, D-30655 Hannover, Germany; Eriksfiord AS, Kunnskapsparken, Postboks 8034, 4068 Stavanger, Norway 1 active fault; basalt; fissure; geomagnetic field; geomagnetism; lava; lithology; magnetic anomaly; magnetic mineral; magnetic property; magnetic susceptibility; oxidation; remanent magnetization; rift zone; stratigraphy; tholeiite; titanomagnetite, Atlantic Ocean; Iceland; Reykjanes Peninsula; Reykjanes Ridge https://www.scopus.com/inward/record.uri?eid=2-s2.0-79951526718&doi=10.1007%2fs11200-011-0007-4&partnerID=40&md5=4711e9ba6996c2b096812546b5911e92 cited By 7 F. Dietze A. Kontny I. Heyde C. Vahle article Ohlendorf2011104 Using the ICDP (International Continental Scientific Drilling Program) deep lake drilling expedition no. 5022 as an example, we describe core processing and sampling procedures as well as new tools developed for subsampling. A manual core splitter is presented that is (1) mobile, (2) able to cut plastic core liners lengthwise without producing swarf of liner material and (3) consists of off-the-shelf components. In order to improve the sampling of sediment cores, a new device, the core sampling assembly (CSA), was developed that meets the following targets: (1) the partitioning of the sediment into discs of equal thickness is fast and precise, (2) disturbed sediment at the inner surface of the liner is discarded during this sampling process, (3) usage of the available sediment is optimised, (4) subsamples are volumetric and oriented, and (5) identical subsamples are taken. The CSA can be applied to D-shaped split sediment cores of any diameter and consists of a divider and a D-shaped scoop. The sampling plan applied for ICDP expedition 5022 is illustrated and may be used as a guideline for planning the efficient partitioning of sediment amongst different lake research groups involved in multidisciplinary projects. For every subsample, the use of quality flags is suggested (1) to document the sample condition, (2) to give a first sediment classification and (3) to guarantee a precise adjustment of logging and scanning data with data determined on individual samples. Based on this, we propose a protocol that might be applied across lake drilling projects in order to facilitate planning and documentation of sampling campaigns and to ensure a better comparability of results. © 2011 Elsevier B.V. Article 2011 10.1016/j.sedgeo.2011.06.007 Sedimentary Geology 239 104 – 115 1-2 Argentina; Patagonia; Information retrieval systems; Lakes; Sedimentology; Well drilling; Argentina; Core processing; Core sampling; Core slicing; Drilling projects; Inner surfaces; Liner material; Multidisciplinary projects; New devices; New protocol; Off-the-shelf components; Patagonia; Research groups; Sampling campaigns; Sampling plans; Sampling procedures; Sampling process; Scanning data; Scientific drilling; Sediment classification; Sediment core; core logging; deep drilling; lake; partitioning; sampling; sediment core; Anoxic sediments https://www.scopus.com/inward/record.uri?eid=2-s2.0-79960980659&doi=10.1016%2fj.sedgeo.2011.06.007&partnerID=40&md5=f67c99225f0370013c5fc9d689ac94a2 Cited by: 28 Christian Ohlendorf Catalina Gebhardt Annette Hahn Pierre Kliem Bernd Zolitschka article Lockner201182 The San Andreas fault accommodates 28-"34-‰mm-‰yr ĝ̂'1 of right lateral motion of the Pacific crustal plate northwestward past the North American plate. In California, the fault is composed of two distinct locked segments that have produced great earthquakes in historical times, separated by a 150-km-long creeping zone. The San Andreas Fault Observatory at Depth (SAFOD) is a scientific borehole located northwest of Parkfield, California, near the southern end of the creeping zone. Core was recovered from across the actively deforming San Andreas fault at a vertical depth of 2.7-‰km (ref. 1). Here we report laboratory strength measurements of these fault core materials at in situ conditions, demonstrating that at this locality and this depth the San Andreas fault is profoundly weak (coefficient of friction, 0.15) owing to the presence of the smectite clay mineral saponite, which is one of the weakest phyllosilicates known. This Mg-rich clay is the low-temperature product of metasomatic reactions between the quartzofeldspathic wall rocks and serpentinite blocks in the fault. These findings provide strong evidence that deformation of the mechanically unusual creeping portions of the San Andreas fault system is controlled by the presence of weak minerals rather than by high fluid pressure or other proposed mechanisms. The combination of these measurements of fault core strength with borehole observations yields a self-consistent picture of the stress state of the San Andreas fault at the SAFOD site, in which the fault is intrinsically weak in an otherwise strong crust. © 2011 Macmillan Publishers Limited. All rights reserved. 2011 English 00280836 10.1038/nature09927 Nature 472 82-86 US Geological Survey, Menlo Park, CA 94025, United States 7341 magnesium; mineral; silicon dioxide, borehole; creep; deformation mechanism; fault gouge; historical record; San Andreas Fault; saponite; serpentine; vertical distribution, article; geography; laboratory; priority journal; strength; United States, California; Parkfield; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-79953738610&doi=10.1038%2fnature09927&partnerID=40&md5=d2bf98ea2248a1701496a7fff041dc35 cited By 291 D.A. Lockner C. Morrow D. Moore S. Hickman article Stein2011453 The area surrounding the Dead Sea was the locus of humankind's migration out of Africa and thus has been the home of peoples since the Stone Age. For this reason, understanding the climate and tectonic history of the region provides valuable insight into archaeology and studies of human history and helps to gain a better picture of future climate and tectonic scenarios. The deposits at the bottom of the Dead Sea are a geological archive of the environmental conditions (e.g., rains, floods, dust storms, droughts) during ice ages and warm ages, as well as of seismic activity in this key region. An International Continental Scientific Drilling Program (ICDP) deep drilling project was performed in the Dead Sea between November 2010 and March 2011. The project was funded by the ICDP and agencies in Israel, Germany, Japan, Norway, Switzerland, and the United States. Drilling was conducted using the new Large Lake Drilling Facility (Figure 1), a barge with a drilling rig run by DOSECC, Inc. (Drilling, Observation and Sampling of the Earth's Continental Crust), a nonprofit corporation dedicated to advancing scientific drilling worldwide. The main purpose of the project was to recover a long, continuous core to provide a high resolution record of the paleoclimate, paleoenvironment, paleoseismicity, and paleomagnetism of the Dead Sea Basin. With this, scientists are beginning to piece together a record of the climate and seismic history of the Middle East during the past several hundred thousand years in millennial to decadal to annual time resolution. 2011 English 00963941 10.1029/2011EO490001 Eos 92 Blackwell Publishing Ltd 453-454 Geological Survey of Israel, Jerusalem, Israel; Department of Geophysics and Planetary Sciences, Tel Aviv University, Ramat Aviv, Israel; Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY, United States 49 archaeology; deep drilling; drilling rig; environmental conditions; paleoclimate; paleoenvironment; paleomagnetism; paleoseismicity; Stone Age; tectonic structure, Dead Sea https://www.scopus.com/inward/record.uri?eid=2-s2.0-83655193054&doi=10.1029%2f2011EO490001&partnerID=40&md5=8565ca73f9cc769fabc4fbd632e1dcc6 cited By 25 M. Stein Z. Ben-Avraham S.L. Goldstein article Brasier2011193 Palaeoproterozoic Tulomozero Formation carbonates of the Onega basin were targeted by ICDP FAR-DEEP Hole 10B. The recovered rocks contain abundant evidence for Palaeoproterozoic gypsum and anhydrite, particularly in the form of pseudomorphs of inclusion-containing nodules, swallow-tail twinned crystals and evaporite dissolution breccias. Similarly, sand-patch fabric indicates the former presence of surface-covering salt crusts in the Palaeoproterozoic. Atmospheric oxygen and seawater sulphate levels at that time must have been sufficient to allow such sulphates to form. Carbonate δ13C values are considered sedimentary or early diagenetic, predating greenschist facies metamorphism associated with the Svecofennian Orogeny. These carbonate δ13C values range from +7.7 to +15.7‰, with the highest (and lowest) values found in dolostones. The dolostones as well as calcitised calcium sulphates record the Lomagundi-Jatuli signal. However evidence for activity of sulphate-reducing and/or methanogenic bacteria seems to be lacking. Dolomite precipitation (or dolomitisation), calcium sulphate calcitisation and production of the high 13C values (processes which typically involve such bacteria in the Phanerozoic) are thus inferred to have proceeded without the direct influence of sulphate reducers and methanogens. The most plausible explanation for the Lomagundi-Jatuli excursion seems to remain significant sequestration of organic carbon in a location yet to be identified. © 2011 Elsevier B.V. 2011 English 03019268 10.1016/j.precamres.2011.05.011 Precambrian Research 189 193-211 Scottish Universities Environmental Research Centre, Scottish Enterprise Technology Park, East Kilbride G75 0QF, Scotland, United Kingdom; Department of Earth Sciences, University of St Andrews, St Andrews KY16 9AL, Scotland, United Kingdom; Geological Survey of Norway, Postboks 6315 Slupen, 7491 Trondheim, Norway; Centre for Geobiology, University of Bergen, Postboks 7803, N-5020 Bergen, Norway; Tallinn Technical University, Institute of Geology, 19086 Tallinn, Estonia 1-2 anhydrite; carbon isotope; carbonate; coastal sediment; dolomite; dolostone; gypsum; methanogenesis; organic carbon; oxygen; precipitation (chemistry); pseudomorph; sabkha; seawater; sulfate, Arkhangelsk [Russian Federation]; Onega Basin; Russian Federation, Centroberyx lineatus https://www.scopus.com/inward/record.uri?eid=2-s2.0-79960420590&doi=10.1016%2fj.precamres.2011.05.011&partnerID=40&md5=cdd41829d2321daf96e1df9daf94f593 cited By 22 A.T. Brasier A.E. Fallick A.R. Prave V.A. Melezhik A. Lepland article Hahn2011 Analysis of sediment samples in the visible to mid infrared (IR) region requires small amounts of sample material and enables rapid and cost efficient geochemical analysis of mineral and organic sediment components. Here we use geochemical properties (total organic and inorganic carbon, biogenic silica, total nitrogen) from the ICDP deep drilling project PASADO to compare three different IR spectroscopy techniques: Diffuse Reflectance Fourier Transform IR Spectrometry (DRIFTS), Attenuated Total Reflectance Fourier Transform IR Spectroscopy (ATR-FTIRS) and Visible Near IR Spectroscopy (VNIRS). ATR-FTIRS and VNIRS are more rapid techniques compared to DRIFTS. Results show that calibration models developed using DRIFTS are most robust (correlation coefficient: R = 0.92 for TIC, R = 0.84 for BSi, R = 0.97 for TOC, R = 0.95 for TN). However, good statistical performance was also obtained by using ATR-FTIRS and VNIRS. When time and costs are limiting factors, these tools may be given preference for rapid biogeochemical screening. Copyright © 2011 by the American Geophysical Union. Article 2011 10.1029/2011GC003686 Geochemistry, Geophysics, Geosystems 12 10 Analytical geochemistry; Anoxic sediments; Biogeochemistry; Carbon; Cost benefit analysis; Fourier transform infrared spectroscopy; Near infrared spectroscopy; Organic carbon; Reflection; Sedimentology; Silica; Spectrometry; Spectrum analysis; Attenuated total reflectance; Biogenic silica; Biogeochemical sediments; Calibration model; Comparative studies; Correlation coefficient; Cost-efficient; Deep drilling; Diffuse reflectance; Diffuse reflectance fourier transform infrared; Fourier transform IR spectroscopy; Geochemical analysis; Geochemical properties; Infrared technique; Inorganic carbon; IR spectrometry; Limiting factors; Midinfrared; Near-IR spectroscopy; Organic sediments; Sediment samples; Statistical performance; Total inorganic carbon; Total nitrogen; total organic carbon (TOC); Visible-near infrared spectroscopy; biogeochemistry; calibration; comparative study; FTIR spectroscopy; inorganic carbon; near infrared; sediment analysis; total organic carbon; Fourier transforms https://www.scopus.com/inward/record.uri?eid=2-s2.0-80054048820&doi=10.1029%2f2011GC003686&partnerID=40&md5=9d48e10c9515f3cd41e25dc1ecd6afea Cited by: 13 A. Hahn P. Kliem C. Ohlendorf B. Zolitschka article Bell2011463 The young (<5Ma) Corinth Rift is an ideal natural laboratory to investigate rift deformation mechanisms by comparing extension rates determined by various methods spanning different depth and time ranges. Corinth Rift geodetic extension rates averaged over 5-100 yr have been interpreted to increase from ~5 mm yr-1 or less in the east to >10-15 mm yr-1 in the west. We quantify total upper-crust and whole-crust extension on three profiles across the Corinth Rift. Whole-crust extension is greater across the central rift (~11-21 km) than across the western part of the rift (~5-13 km). This correlates with the overall rift morphology, which shows maximum basement subsidence, sediment accumulation, rift width and greatest summed Late Quaternary fault displacements in the central basin, but contrasts with the pattern of geodetic extension rates which are greater to the west of the central basin. The E-W increase in strain rates interpreted from geodetic data cannot have persisted over rift history to produce the observed rift morphology. We suggest the discrepancy between short-term and long-term extension patterns is related to shifts in the loci of maximum extension due to fault growth and linkage during Corinth Rift history, and is likely a characteristic of rift development in general. Total upper-crust and whole-crust extension estimates in the western rift, where extension estimates are best constrained, are within error. We propose that uniform pure-shear extension is a viable extension mechanism in the western rift and crustal extension estimates do not require the existence of a major active N-S dipping detachment fault. © 2011 The Authors Geophysical Journal International © 2011 RAS. Article 2011 English 1365246X 10.1111/j.1365-246X.2011.05077.x Geophysical Journal International 186 463 – 470 2 Central Greece; Greece; Gulf of Corinth; Ionian Sea; Mediterranean Sea; Anoxic sediments; Estimation; Geodesy; Morphology; Sedimentology; Tectonics; Central Basin; Continental tectonics; Crustal extension; Deformation mechanism; Detachment fault; Europe; Fault displacement; Fault growth; Geodetic data; Late quaternary; Natural laboratories; Neotectonics; Sediment accumulation; Sedimentary basin; Time range; active fault; deformation mechanism; detachment fault; extensional tectonics; fault displacement; geodesy; geomorphology; neotectonics; rift zone; sedimentary basin; strain rate; subsidence; upper crust; Strain rate https://www.scopus.com/inward/record.uri?eid=2-s2.0-79960356588&doi=10.1111%2fj.1365-246X.2011.05077.x&partnerID=40&md5=f75fbb185805ef603522e55ff90dac2d Cited by: 33; All Open Access, Bronze Open Access, Green Open Access Rebecca E. Bell Lisa C. McNeill Timothy J. Henstock Jonathan M. Bull article Haimson201145 An extensive true triaxial testing program was carried out on core samples from three ICDP-sponsored deep scientific boreholes, KTB (Germany), SAFOD (United States), and TCDP (Taiwan). The three rocks differ in the processes that formed them and in many of their mechanical properties. However, all three rocks exhibited similar failure mechanism, in which induced or reopened microcracks are primarily aligned with the σ1-σ2 plane, and the developed fault is steeply inclined in the σ3 direction. Rock strength in all tested rocks increases with σ2 when σ3 is kept constant. Thus, the common Mohr-type criteria, which ignore the effect of σ2, typically underestimate rock strength. Rather a 3D criterion that involves all three principal stresses represents well experimental results. Fracture plane slope for the same σ3 steepens as σ2 rises, contrary to Mohr-type criteria. With respect to deformation, the onset of dilatancy increases with σ2. In conclusion, true triaxial tests conducted on cores from three scientific boreholes, revealed important details of mechanical behavior not otherwise observed in conventional triaxial tests. In addition, they show mechanical behavior similarities as related to σ2 effect regardless of rock type. © 2010 Elsevier B.V. 2011 English 00401951 10.1016/j.tecto.2010.10.011 Tectonophysics 503 45-51 Dept. of Materials Science and Engineering and the Geological Engineering Program, University of Wisconsin, 1509 University Avenue, Madison, WI, 53706, United States 1-2 Dilatancy; Fault angle; Scientific boreholes; True triaxial strength; True triaxial testing, Deformation; Mechanical engineering; Mechanical properties; Rock mechanics; Testing, Rocks, borehole; deformation; dilatancy; failure mechanism; mechanical property; microcrack; rock mechanics; triaxial test, Germany; Taiwan; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-79954642377&doi=10.1016%2fj.tecto.2010.10.011&partnerID=40&md5=15821fb817ddead48ed292c695ef54d2 cited By 21 B. Haimson article Haimson201145 An extensive true triaxial testing program was carried out on core samples from three ICDP-sponsored deep scientific boreholes, KTB (Germany), SAFOD (United States), and TCDP (Taiwan). The three rocks differ in the processes that formed them and in many of their mechanical properties. However, all three rocks exhibited similar failure mechanism, in which induced or reopened microcracks are primarily aligned with the σ1-σ2 plane, and the developed fault is steeply inclined in the σ3 direction. Rock strength in all tested rocks increases with σ2 when σ3 is kept constant. Thus, the common Mohr-type criteria, which ignore the effect of σ2, typically underestimate rock strength. Rather a 3D criterion that involves all three principal stresses represents well experimental results. Fracture plane slope for the same σ3 steepens as σ2 rises, contrary to Mohr-type criteria. With respect to deformation, the onset of dilatancy increases with σ2. In conclusion, true triaxial tests conducted on cores from three scientific boreholes, revealed important details of mechanical behavior not otherwise observed in conventional triaxial tests. In addition, they show mechanical behavior similarities as related to σ2 effect regardless of rock type. © 2010 Elsevier B.V. 2011 English 00401951 10.1016/j.tecto.2010.10.011 Tectonophysics 503 45-51 Dept. of Materials Science and Engineering and the Geological Engineering Program, University of Wisconsin, 1509 University Avenue, Madison, WI, 53706, United States 1-2 Dilatancy; Fault angle; Scientific boreholes; True triaxial strength; True triaxial testing, Deformation; Mechanical engineering; Mechanical properties; Rock mechanics; Testing, Rocks, borehole; deformation; dilatancy; failure mechanism; mechanical property; microcrack; rock mechanics; triaxial test, Germany; Taiwan; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-79954642377&doi=10.1016%2fj.tecto.2010.10.011&partnerID=40&md5=15821fb817ddead48ed292c695ef54d2 cited By 21 B. Haimson article Becken201187 The seismicity pattern along the San Andreas fault near Parkfield and Cholame, California, varies distinctly over a length of only fifty kilometres. Within the brittle crust, the presence of frictionally weak minerals, fault-weakening high fluid pressures and chemical weakening are considered possible causes of an anomalously weak fault northwest of Parkfield. Non-volcanic tremor from lower-crustal and upper-mantle depths is most pronounced about thirty kilometres southeast of Parkfield and is thought to be associated with high pore-fluid pressures at depth. Here we present geophysical evidence of fluids migrating into the creeping section of the San Andreas fault that seem to originate in the region of the uppermost mantle that also stimulates tremor, and evidence that along-strike variations in tremor activity and amplitude are related to strength variations in the lower crust and upper mantle. Interconnected fluids can explain a deep zone of anomalously low electrical resistivity that has been imaged by magnetotelluric data southwest of the Parkfield-Cholame segment. Near Cholame, where fluids seem to be trapped below a high-resistivity cap, tremor concentrates adjacent to the inferred fluids within a mechanically strong zone of high resistivity. By contrast, subvertical zones of low resistivity breach the entire crust near the drill hole of the San Andreas Fault Observatory at Depth, northwest of Parkfield, and imply pathways for deep fluids into the eastern fault block, coincident with a mechanically weak crust and the lower tremor amplitudes in the lower crust. Fluid influx to the fault system is consistent with hypotheses of fault-weakening high fluid pressures in the brittle crust. © 2011 Macmillan Publishers Limited. All rights reserved. 2011 English 00280836 10.1038/nature10609 Nature 480 87-90 GFZ German Research Centre for Geosciences, Telegrafenberg, 14473 Potsdam, Germany; University Potsdam, Institute of Geosciences, Karl-Liebknecht-Strasse 24, 14476 Potsdam-Golm, Germany; US Geological Survey, MS 964, Box 25046, Denver, CO 80225, United States; Westfälische Wilhelms Universität Münster, Institute of Geophysics, Corrensstrasse 24, 48149 Münster, Germany 7375 mineral, amplitude; correlation; crust; data set; electrical resistivity; fluid; mantle; pressure effect, amplitude modulation; anisotropy; article; biogeographic region; chemical reaction; earthquake; electrical parameters; enzyme kinetics; friction; liquid; nonhuman; porosity; precipitation; priority journal; rock; salinity; san andreas fault; velocity; volcano, California; San Andreas; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-82555195565&doi=10.1038%2fnature10609&partnerID=40&md5=f8adaa53b017130e6949e5cd60bf4626 cited By 159 M. Becken O. Ritter P.A. Bedrosian U. Weckmann article Gebhardt2011357 Laguna Potrok Aike is a bowl-shaped maar lake in southern Patagonia, Argentina, with a present mean diameter of ~3.5km and a maximum water depth of ~100m. Seismic surveys were carried out between 2003 and 2005 in order to get a deeper knowledge on the lake sediments and the deeper basin geometries. A raytracing model of the Laguna Potrok Aike basin was calculated based on refraction data while sparker data were additionally used to identify the crater-wall discordance and thus the upper outer shape of the maar structure. The combined data sets show a rather steep funnel-shaped structure embedded in the surrounding Santa Cruz Formation that resembles other well-known maar structures. The infill consists of up to 370m lacustrine sediments underlain by probably volcanoclastic sediments of unknown thickness. The lacustrine sediments show a subdivision into two sub-units: (a) the upper with seismic velocities between 1500 and 1800ms-1, interpreted as unconsolidated muds, and (b) the lower with higher seismic velocities of up to 2350ms-1, interpreted as lacustrine sediments intercalated with mass transport deposits of different lithology and/or coarser-grained sediments. The postulated volcanoclastic layer has acoustic velocities of >2400ms-1. The lake sediments were recently drilled within the PASADO project in the framework of the International Continental Scientific Drilling Program (ICDP). Cores penetrated through lacustrine unconsolidated sediments down to a depth of ~100m below lake floor. This minimal thickness for the unconsolidated and low-velocity lithologies is in good agreement with our raytracing model. © 2011 Elsevier B.V. Article 2011 10.1016/j.jvolgeores.2010.12.019 Journal of Volcanology and Geothermal Research 201 357 – 363 1-4 Argentina; Laguna Potrok Aike; Santa Cruz [Argentina]; Anoxic sediments; Lakes; Lithology; Refraction; Seismic waves; Seismology; Settling tanks; Submarine geophysics; Surveys; Velocity; Explosive volcanism; Maars; PASADO project; Sedimentary basin; South America; drilling; explosive volcanism; lithology; maar; ray tracing; sedimentary basin; seismic reflection; seismic refraction; seismic survey; seismic velocity; volcaniclastic deposit; Sedimentology https://www.scopus.com/inward/record.uri?eid=2-s2.0-79953048051&doi=10.1016%2fj.jvolgeores.2010.12.019&partnerID=40&md5=8a2f6e76f46d5869ff34a4886eee05d5 Cited by: 33; All Open Access, Green Open Access M. De Batist F.S. Anselmetti D. Ariztegui T. Haberzettl C. Kopsch C. Ohlendorf B. Zolitschka article Itävaara2011295 This paper demonstrates the first microbiological sampling of the Outokumpu deep borehole (2516m deep) aiming at characterizing the bacterial community composition and diversity of sulphate-reducing bacteria (SRB) in Finnish crystalline bedrock aquifers. Sampling was performed using a 1500-m-long pressure-tight tube that provided 15 subsamples, each corresponding to a 100-m section down the borehole. Microbial density measurements, as well as community fingerprinting with 16S rRNA gene-based denaturing gradient gel electrophoresis, demonstrated that microbial communities in the borehole water varied as a function of sampling depth. In the upper part of the borehole, bacteria affiliated to the family Comamonadaceae dominated the bacterial community. Further down the borehole, bacteria affiliated to the class Firmicutes became more prominent and, according to 16S rRNA gene clone libraries, dominated the bacterial community at 1400-1500m. In addition, the largest number of bacterial classes was observed at 1400-1500m. The dsrB genes detected in the upper part of the borehole were more similar to the dsrB genes of cultured SRBs, such as the genus Desulfotomaculum, whereas in the deeper parts of the borehole, the dsrB genes were more closely related to the uncultured bacteria that have been detected earlier in deep earth crust aquifers. FEMS Microbiology Ecology © 2011 Federation of European Microbiological Societies. No claim to original Finnish government works. Article 2011 English 15746941 10.1111/j.1574-6941.2011.01111.x FEMS Microbiology Ecology 77 295 – 309 2 Bacteriological Techniques; Biodiversity; Colony Count, Microbial; DNA, Bacterial; Finland; Gene Library; Phylogeny; RNA, Ribosomal, 16S; Sulfur-Reducing Bacteria; Water; Water Microbiology; Baltic Shield; Finland; Ita Suomen; Outokumpu; Bacteria (microorganisms); Comamonadaceae; Desulfotomaculum; Firmicutes; uncultured bacterium; bacterial DNA; RNA 16S; water; aquifer; bacterium; bedrock; borehole; community composition; crystalline rock; dominance; electrokinesis; extremophile; groundwater; microbial community; sampling; species diversity; vertical distribution; article; bacterial count; biodiversity; chemistry; classification; Finland; gene library; genetics; Gram negative anaerobic bacteria; isolation and purification; microbiological examination; microbiology; phylogeny https://www.scopus.com/inward/record.uri?eid=2-s2.0-80955177493&doi=10.1111%2fj.1574-6941.2011.01111.x&partnerID=40&md5=6bba1ae811bc7c3425f6c995bc9940d5 Cited by: 101; All Open Access, Bronze Open Access Merja Itävaara Mari Nyyssönen Anu Kapanen Aura Nousiainen Lasse Ahonen Ilmo Kukkonen article sd11462011 2011 10.2204/iodp.sd.11.04.2011 Scientific Drilling 11 46-47 https://sd.copernicus.org/articles/11/46/2011/ M. Stein Z. Ben-Avraham S. Goldstein A. Agnon D. Ariztegui A. Brauer G. Haug E. Ito Y. Yasuda article Ellsworth201139 Damage to fault-zone rocks during fault slip results in the formation of a channel of low seismic-wave velocities. Within such channels guided seismic waves, denoted by F g, can propagate. Here we show with core samples, well logs and F g-waves that such a channel is crossed by the SAFOD (San Andreas Fault Observatory at Depth) borehole at a depth of 2.7 km near Parkfield, California, USA. This laterally extensive channel extends downwards to at least half way through the seismogenic crust, more than about 7 km. The channel supports not only the previously recognized Love-type- (F L) and Rayleigh-type- (F R) guided waves, but also a new fault-guided wave, which we name F Φ. As recorded 2.7 km underground, F Φ is normally dispersed, ends in an Airy phase, and arrives between the P- and S-waves. Modelling shows that F Φ travels as a leaky mode within the core of the fault zone. Combined with the drill core samples, well logs and the two other types of guided waves, F Φ at SAFOD reveals a zone of profound, deep, rock damage. Originating from damage accumulated over the recent history of fault movement, we suggest it is maintained either by fracturing near the slip surface of earthquakes, such as the 1857 Fort Tejon M 7.9, or is an unexplained part of the fault-creep process known to be active at this site. © The Geological Society of London 2011. 2011 English 03058719 10.1144/SP359.3 Geological Society Special Publication 359 39-53 US Geological Survey, 345 Middlefield Road, MS-977, Menlo Park, CA 94025, United States; Institute of Earth Science and Engineering, University of Auckland, Auckland 1142, New Zealand 1 earthquake; fault slip; fault zone; P-wave; Rayleigh wave; S-wave; seismic wave, California; San Andreas; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-84055176128&doi=10.1144%2fSP359.3&partnerID=40&md5=d47374a8d84b8ea8505e1f958cb6a7b2 cited By 36 W.L. Ellsworth article Gupta201153 2011 English 18168957 10.2204/iodp.sd.12.07.2011 Scientific Drilling 53-54 National Geophysical Research Institute (CSIR-NGRI), Uppal Road, Hyderabad, 500 007, India; Ministry of Earth Sciences (MoES), C.G.O. Complex, Lodhi Road, New Delhi 110 003, India 12 https://www.scopus.com/inward/record.uri?eid=2-s2.0-83455263847&doi=10.2204%2fiodp.sd.12.07.2011&partnerID=40&md5=0e33bc4ef29c208a01c0b418f1abcb4b cited By 22 H. Gupta S. Nayak article Zhao201112 Article 2011 10.3799/dqkx.2011.002 Diqiu Kexue - Zhongguo Dizhi Daxue Xuebao/Earth Science - Journal of China University of Geosciences 36 12 – 16 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-79952714578&doi=10.3799%2fdqkx.2011.002&partnerID=40&md5=a9ea28854623ac3d971c70f74e995b9e Cited by: 4 Qing-Le Zhao Huai-Chun Wu Hai-Yan Li Shi-Hong Zhang article https://doi.org/10.1029/2011EO250001 Three decades ago, a landmark paper by Alvarez et al. [1980] proposed that an asteroid impact 65.5 million years ago was the cause of the mass extinction of about 75% of species, including the dinosaurs, at the boundary between the Cretaceous and Paleogene periods (K-Pg), formerly known as the Cretaceous-Tertiary (K-T) boundary. Alvarez et al. used geochemical studies on carbonate sequences from Italy, Denmark, and New Zealand to study the boundary layer, which was enriched in iridium and other platinum group elements (PGEs) at concentrations well above background levels. They associated these enrichments with the collision of an asteroid that injected large amounts of pulverized debris into the atmosphere, resulting in blockage of solar radiation, global cooling, and a shutdown of photosynthesis. 2011 https://doi.org/10.1029/2011EO250001 Eos, Transactions American Geophysical Union 92 209-210 25 Chicxulub impact crater, history https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2011EO250001 Jaime Urrutia-Fucugauchi Antonio Camargo-Zanoguera Ligia Pérez-Cruz article Xi2011253 The Songliao Basin is the largest oil-bearing basin in China. In the absence of sufficient evidence, the possibility of seawater incursion(s) into the Songliao Basin remains controversial. Recently, we discovered relatively abundant foraminifera fossils from units 1 and 2 of the Nenjiang Formation of borehole SK-1. Benthic foraminifera (Gavlinella sp., Anomalinoides sp., Pullenia sp., Haplophragmoides sp., Karrorulina hokkaidoana, Clavulinoides sp.), as well as planktonic foraminifera (Archaeoglobigerina blowi, Archaeoglobigerina cretacea and Hedbergella flandrini), were identified. These fossils were widely distributed in the marine Cretaceous. According to the global distribution of the above-mentioned planktonic foraminifera, the age of these fossil bearing strata appears to be Late Coniacian to Santonian. More importantly, these foraminifera provide direct evidence for marine water incursions into the Songliao Basin during deposition of the Lower Nenjiang Formation. © 2011 Science China Press and Springer-Verlag Berlin Heidelberg. Letter 2011 English 10016538 10.1007/s11434-010-4269-y Chinese Science Bulletin 56 Science in China Press 253 – 256 School of Earth Science and Resources, China University of Geosciences (Beijing), Beijing 100083, China; Exploration and Development Research Institute of Daqing Oil Field Company, Daqing 163712, China 3 Coniacian; Foraminifera; Haplophragmoides; Hedbergella; Pullenia https://www.scopus.com/inward/record.uri?eid=2-s2.0-79251471415&doi=10.1007%2fs11434-010-4269-y&partnerID=40&md5=3469c785ed411a45024bb54587678639 Cited by: 57; All Open Access, Bronze Open Access Dang Peng Xi Xiao Qiao Wan Zhi Qiang Feng Shun Li Zi Hui Feng Jian Zhong Jia Xia Jing Wei Min Si article Wiersberg2011148 In this contribution we present results from two individual gas monitoring experiments which were conducted during the drilling of the SAFOD (San Andreas Fault Observatory at Depth) boreholes. Gas from circulating drilling mud was monitored during the drilling the SAFOD III side tracks and was later analyzed for δ13C (CH4, C2H6 and C3H8), H/D (CH4) and noble gas isotopes. Furthermore, gas accumulations induced by drill pipe retrieval ("trip gas") from the SAFOD MH and the SAFOD III boreholes were also investigated. The data are interpreted in the context of gas migration processes and the permeability structure of the San Andreas Fault (SAF) around two actively deforming zones at 3194m and 3301m borehole depth. Helium isotope ratios of 0.86 Ra at 3203m and between 0.51 and 0.88 Ra at 3262m (Ra is the atmospheric 3He/4He ratio) indicate an improved flow of mantle volatiles between both fault strands. Much lower values were observed at 3147m (0.26 Ra) and 3312m (0.22 Ra). Hydrocarbon concentrations coincide with the occurrence of shale at ~3150-3200m and below ~3310m depth. The molecular and isotope composition of hydrocarbons and their spatial distributions imply hydrocarbon generation by thermal degradation of organic matter followed by extensive diffusion loss. Carbon isotope data furthermore suggest a thermal maturity of the source rock of approx. 1.4%R0. The concentration of trip gas is generally low in the interval 3100. m-3450. m but exhibits high spatial variability. At 3128. m and 3223. m depth, the trip gas concentrations are as low as in the granite section of the SAFOD Main Hole. Considerable variations of Ra values, trip gas concentrations, and the molecular composition of hydrocarbons when penetrating the active fault strands let us conclude that the permeability of the fault transverse to the fault direction is limited and that the active fault has not been breached over many earthquake cycles such that little or no fluid exchange took place. Diffusion is the dominant mechanism controlling hydrocarbon migration through the fault strands. The elevated Ra values between both fault strands may reflect either episodic or continuous flow of mantle-derived fluids, suggestive of some limited permeability parallel to the fault direction. © 2011 Elsevier B.V. 2011 English 00092541 10.1016/j.chemgeo.2011.02.016 Chemical Geology 284 148-159 Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences, Telegrafenberg, 14473 Potsdam, Germany 1-2 A-thermal; Active fault; Carbon isotopes; Continuous flows; Deforming zone; Diffusion loss; Dominant mechanism; Drilling mud; Drilling mud gas; Fault direction; Fault strands; Fluid exchange; Gas accumulation; Gas concentration; Gas migration; Gas monitoring; Helium isotopes; Hydrocarbon generation; Hydrocarbon migration; Isotope compositions; Mantle volatiles; Molecular compositions; Noble gas isotopes; Organic matter; Permeability structure; SAFOD; San Andreas Fault; Shale gas; Source rocks; Spatial variability; Thermal degradations, Boreholes; Boring; Buildings; Drill pipe; Helium; Hydrocarbons; Inert gases; Isotopes; Observatories; Oil well drilling; Petroleum geology; Shale; Tectonics, Gas permeability, active fault; borehole; chemical composition; diffusion; drilling; helium isotope; hydrocarbon migration; isotopic composition; noble gas; organic matter; permeability; San Andreas Fault; spatial distribution https://www.scopus.com/inward/record.uri?eid=2-s2.0-79954627078&doi=10.1016%2fj.chemgeo.2011.02.016&partnerID=40&md5=bcbf76b9d5e9779c317bc2a779f242c1 cited By 35 T. Wiersberg J. Erzinger article Gorbatsevich2011207 We present the results of laboratory measurements of the elastic and nonelastic properties of drill core samples from depths of 94-2298 m in the Outokumpu Deep Drill Hole, eastern Finland. A total of 43 cubic rock samples were prepared (30-40 mm side length) and measured with the method of acoustopolariscopy under ambient conditions. In addition, the average velocities were calculated from the modal composition of the rocks. The measurement results provide the complete velocity matrices of the samples with the main components of P-waves as well as S-waves and their anisotropy factors. From the surface down to a depth of ∼1300 m (mostly metasediments), the Outokumpu rocks were found to be strongly anisotropic. The lowest measured anisotropy values were observed in the ∼1300-1600 m depth range (ophiolite-derived altered ultramafic rocks and metasediments). In the lower part of the hole from 1600 m to the hole bottom (metasediments and pegmatitic granite), the velocity anisotropy was variable. The effect of linear acoustic anisotropic absorption (LAAA) is exhibited in samples from the upper and lower sections of the drill hole. We attribute the variations in P- and S-wave velocities and their anisotropies to the variation in rock types and the drilling-induced relaxation of pressure (and to a minor degree temperature), which has resulted in decompaction and the formation of micro-cracks in the drill core. Therefore, a linear decrease in seismic velocities as a function of depth is observed in the laboratory measurements. Article 2011 English 978-952217152-8 07828535 Special Paper of the Geological Survey of Finland 2011 Kukkonen I.T. 207 – 218 51 Finland; Ita Suomen; Outokumpu; borehole; crystalline rock; elastic property; igneous rock; laboratory method; metamorphic rock; metasediment; microcrack; P-wave; S-wave; seismic anisotropy; seismic velocity; ultramafic rock https://www.scopus.com/inward/record.uri?eid=2-s2.0-80051883040&partnerID=40&md5=ed82bf2a730a5a391aaad1709b237d41 Cited by: 3 Felix F. Gorbatsevich Mikhail V. Kovalevsky Olga M. Trishina article Heesakkers20112395 We analyze the structure of the Archaean Pretorius fault in TauTona mine, South Africa, as well as the rupture-zone that recently reactivated it. The analysis is part of the Natural Earthquake Laboratory in South African Mines (NELSAM) project that utilizes the access to 3. 6 km depth provided by the mining operations. The Pretorius fault is a ~10 km long, oblique-strike-slip fault with displacement of up to 200 m that crosscuts fine to very coarse grain quartzitic rocks in TauTona mine. We identify here three structural zones within the fault-zone: (1) an outer damage zone, ~100 m wide, of brittle deformation manifested by multiple, widely spaced fractures and faults with slip up to 3 m; (2) an inner damage zone, 25-30 m wide, with high density of anastomosing conjugate sets of fault segments and fractures, many of which carry cataclasite zones; and (3) a dominant segment, with a cataclasite zone up to 50 cm thick that accommodated most of the Archaean slip of the Pretorius fault, and is regarded as the 'principal slip zone' (PSZ). This fault-zone structure indicates that during its Archaean activity, the Pretorius fault entered the mature fault stage in which many slip events were localized along a single, PSZ. The mining operations continuously induce earthquakes, including the 2004, M2. 2 event that rejuvenated the Pretorius fault in the NELSAM project area. Our analysis of the M2. 2 rupture-zone shows that (1) slip occurred exclusively along four, pre-existing large, quasi-planer segments of the ancient fault-zone; (2) the slipping segments contain brittle cataclasite zones up to 0. 5 m thick; (3) these segments are not parallel to each other; (4) gouge zones, 1-5 mm thick, composed of white 'rock-flour' formed almost exclusively along the cataclasite-host rock contacts of the slipping segments; (5) locally, new, fresh fractures branched from the slipping segments and propagated in mixed shear-tensile mode; (6) the maximum observed shear displacement is 25 mm in oblique-normal slip. The mechanical analysis of this rupture-zone is presented in Part II (Heesakkers et al., Earthquake Rupture at Focal Depth, Part II: Mechanics of the 2004 M2. 2 Earthquake Along the Pretorius Fault, TauTona mine, South Africa 2011, this volume). © 2011 Springer Basel AG. Article 2011 English 00334553 10.1007/s00024-011-0354-7 Pure and Applied Geophysics 168 2395 – 2425 School of Geology and Geophysics, University of Oklahoma, Norman, OK, United States; Chevron ETC, 1500 Louisiana St, Houston, TX 77002, United States; AngloGold Ashanti, Carletonville, Gauteng, South Africa 12 Brittle faulting; Deep mines; earthquake mechanics; earthquake rupture zone; Fault reactivation; Fault rock, Earthquakes; Fracture; Rocks; Tectonics, Fault slips, brittle deformation; cataclasite; displacement; earthquake rupture; fault zone; fracture; quartzite; strike-slip fault, South Africa https://www.scopus.com/inward/record.uri?eid=2-s2.0-84857554632&doi=10.1007%2fs00024-011-0354-7&partnerID=40&md5=71482a0c2996d825a3fefc441c2b7e8e Cited by: 51 V. Heesakkers S. Murphy Z. Reches article Lin2025 Article 2011 Acta Geologica Sinica 85 1806-1822 11 H. Ran J. Zhang W. Xie Y. Zhang Z. Song J. Xiang F. Liu Q. Feng T. Yan M. Jia S. Tao J. Hu article Scholz201138 Scientific drill cores recovered from Lake Malawi exhibit a remarkable down-core lithologic variability, and are indicative of radically changing environmental conditions forced by large-amplitude lake-level shifts over the past 150kyr. Here we present detailed lithologic and sedimentary fabric descriptions of the key sedimentary units, along with down-core physical properties data, down-core organic matter geochemistry (TOC, C/N, and δ13C data sets), and images and descriptions from core sections and from sediment smear slide microscopy. These data reveal a fundamental change in Lake Malawi's limnology and regional climate at ca. 60-70ka. Prior to this time the lake was characterized by large-amplitude variations in lake level and water chemistry, but after 60ka the lake remained comparatively high, and the central basin drill site accumulated mainly organic-rich, laminated sediments. Organic matter sources changed dramatically during the different lake stages. During major lake high stands, a mixed assemblage of algal (diatom-dominated), woodland and aquatic macrophyte (C4-pathway), and grassland (C3-pathway) organic matter was deposited, whereas during extreme low lake stages (water depths &lt;200m), when saline, alkaline lakes persisted in the basin, sediments with minimal amounts of algal-dominated organic matter accumulated and were preserved. © 2010 Elsevier B.V. 2011 English 00310182 10.1016/j.palaeo.2010.10.028 Palaeogeography, Palaeoclimatology, Palaeoecology 303 38-50 Department of Earth Sciences, Syracuse University, Syracuse NY, 13244, United States; Department of Earth Science, University of Bergen, N-5007 Bergen, Norway; Large Lakes Observatory and Department of Geological Sciences, University of Minnesota Duluth, Duluth, MN 55812, United States 1-4 diatom; fossil record; hydrochemistry; lithostratigraphy; macrophyte; organic matter; paleoclimate; paleolimnology; Pleistocene; sediment core, East African Lakes; East African Rift; Lake Malawi, algae; Bacillariophyta https://www.scopus.com/inward/record.uri?eid=2-s2.0-79953157977&doi=10.1016%2fj.palaeo.2010.10.028&partnerID=40&md5=810de2fcf6c00c63136a5f6574039365 cited By 18 C.A. Scholz M.R. Talbot E.T. Brown R.P. Lyons article Hanselman2011201 Fossil pollen and charcoal analyses of sediments from Lake Titicaca, Peru/Bolivia, provide a record of palaeoclimatic variation spanning four full glacial cycles. Pollen, aquatic microfossils, and charcoal, as well as previously published data including diatom assemblages, carbonate content, and stable carbon isotopic ratios of organic carbon, indicate that interglacials were warm and dry whereas the peaks of glacials were cold and wet. Each of the interglacials documented in the record are somewhat different, with those of MIS 5e and MIS 9 inducing lower lake levels and a drier vegetation signature than those of MIS 7 and 1. The presence of charcoal particles in sediments deposited during previous interglacials provides evidence of the long-term role of fire in shaping Andean ecosystems. © 2011 Elsevier B.V. Article 2011 10.1016/j.palaeo.2011.03.002 Palaeogeography, Palaeoclimatology, Palaeoecology 305 201 – 214 1-4 Andes; Bolivia; Lake Titicaca; Peru; Bacillariophyta; charcoal; depositional environment; diatom; fire history; fossil assemblage; glacial-interglacial cycle; interglacial; lacustrine deposit; microfossil; paleoclimate; palynology; vegetation dynamics; vegetation history https://www.scopus.com/inward/record.uri?eid=2-s2.0-79955481503&doi=10.1016%2fj.palaeo.2011.03.002&partnerID=40&md5=3f9938493aa8912e2f57959da9805883 Cited by: 39 Jennifer A. Hanselman Mark B. Bush William D. Gosling Aaron Collins Christopher Knox Paul A. Baker Sheri C. Fritz article Litt2011477 Sedimentary archives host a wealth of information that can be used to reconstruct paleoclimate as well as the tectonic and volcanic histories of specific regions. Long and continuous archives from the oceans have been collected in thousands of locations by scientific ocean drilling programs over the past 40 years. In contrast, suitable continental archives are rare because terrestrial environments are generally nondepositional and/or subject to erosion. Lake sediments provide ideal drilling targets to overcome this limitation if suitable lakes at key locations have existed continuously for a long time. 2011 English 00963941 10.1029/2011EO510002 Eos 92 477-479 Steinmann Institute of Geology, Mineralogy and Paleontology, Bonn University, Bonn, Germany; Eawag: Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland; Department of Geological Engineering, Eastern Mediterranean Centre for Oceanography and Limnology, Istanbul Technical University, Istanbul, Turkey; Helmholtz-Zentrum für Ozeanforschung Kiel, Forschungszentrum für Marine Geowissenschaften, Kiel, Germany 51 lacustrine deposit; marine sediment; Ocean Drilling Program; paleoclimate; reconstruction, Anatolia; Turkey https://www.scopus.com/inward/record.uri?eid=2-s2.0-84855316074&doi=10.1029%2f2011EO510002&partnerID=40&md5=7641bec8685ebfcfa0ad6af9da3ea566 cited By 30 T. Litt F.S. Anselmetti M.N. Çağatay R. Kipfer S. Krastel H.-U. Schmincke M. Sturm article Misiti201150 Viscosities of shoshonitic and latitic melts, relevant to the Campi Flegrei caldera magmas, have been experimentally determined at atmospheric pressure and 0.5GPa, temperatures between 840K and 1870K, and H2O contents from 0.02 to 3.30wt.%.The concentric cylinder technique was employed at atmospheric pressure to determine viscosity of nominally anhydrous melts in the viscosity range of 101.5-103Pas. The micropenetration technique was used to determine the viscosity of hydrous and anhydrous melts at atmospheric pressure in the high viscosity range (1010Pas). Falling sphere experiments were performed at 0.5GPa in the low viscosity range (from 100.35 to 102.79Pas) in order to obtain viscosity data of anhydrous and hydrous melts. The combination of data obtained from the three different techniques adopted permits a general description of viscosity as a function of temperature and water content using the following modified VFT equation:logη=-a+bT-c+dT-e·expg·wTwhere η is the viscosity in Pa·s, T the temperature in K, w the H2O content in wt.%, and a, b, c, d, e, and g are the VFT parameters. This model reproduces the experimental data (95 measurements) with a 1σ standard deviation of 0.19 and 0.22 log units for shoshonite and latite, respectively. The proposed model has been applied also to a more evolved composition (trachyte) from the same area in order to create a general model applicable to the whole compositional range of Campi Flegrei products.Moreover, speed data have been used to constrain the ascent velocity of latitic, shoshonitic, and trachytic melts within dikes. Using petrological data and volcanological information (geometrical parameters of the eruptive fissure and depth of magma storage), we estimate a time scale for the ascent of melt from 9. km to 4. km depth (where deep and shallow reservoirs, respectively, are located) in the order of few minutes. Such a rapid ascent should be taken into account for the hazard assessment in the Campi Flegrei area. © 2011 Elsevier B.V. Article 2011 English 00092541 10.1016/j.chemgeo.2011.08.010 Chemical Geology 290 50 – 59 1-2 Campania [Italy]; Campi Flegrei; Italy; Napoli [Campania]; Atmospheric pressure; Atmospheric temperature; Atmospherics; Cylinders (shapes); Reservoirs (water); Spheres; Thermal logging; Viscometers; Water content; Campi Flegrei; Concentric cylinders; Falling sphere; Latites; Micropenetration; Shoshonites; air temperature; atmospheric pressure; caldera; experimental study; hazard assessment; magmatic differentiation; P-T conditions; petrology; shoshonite; viscosity; volcanology; Viscosity https://www.scopus.com/inward/record.uri?eid=2-s2.0-80054917604&doi=10.1016%2fj.chemgeo.2011.08.010&partnerID=40&md5=8d421390754c57472ae170d86667b7d9 Cited by: 24 V. Misiti F. Vetere C. Freda P. Scarlato H. Behrens A. Mangiacapra D.B. Dingwell article Dietze2011133 This study examined the rock magnetic properties and magnetic mineralogy of serpentinite, skarn, black schist and mica schist of the Outokumpu (OKU) rock type assemblage, which occur between 1314 and 1515 m in the Outokumpu Deep Drill Hole in Eastern Finland. This depth interval is related to pronounced magnetic anomalies. A banded magnetic anomaly pattern, similar to the one observed in the OKU drill cores, is seen in aeromagnetic surveys for the surface in the vicinity of the OKU borehole. Magnetic logging has revealed that the magnetic anomalies are mostly related to the ferrimagnetic serpentinite units in the OKU assemblage. The serpentinite units show a significant scattering of magnetic susceptibility (κ) from 0.04 to 192.7*10-3 SI and natural remanent magnetization (NRM) from 0.06 to 45.1 A/m, indicating a heterogeneous distribution of ferrimagnetic minerals in the ultramafic rocks. The main magnetic minerals are magnetite and pyrrhotite. Furthermore, variation in the Königsberger ratio (Q) from below 1 up to 16 indicates that some ultramafic rocks in the OKU assemblage are able to carry a remanent magnetization (Q-ratio > 1). The strong scattering of rock magnetic properties is interpreted to reflect a complex geological history of the studied rocks. Magnetite is known to form during the serpentinization of ultramafic rocks on the sea floor or during subduction-related processes. In the OKU assemblage it was partially decomposed during early deformation stages by listwaenite-birbirite-type carbonatequartz alteration. During subsequent events of regional deformation, the magnetic minerals were deformed or some new formation of magnetic minerals occurred. Article 2011 English 978-952217152-8 07828535 Special Paper of the Geological Survey of Finland 2011 Kukkonen I.T. 133 – 150 51 Finland; Ita Suomen; Outokumpu; borehole logging; deep drilling; magnetic anomaly; magnetic property; magnetic survey; magnetic susceptibility; magnetite; mineralogy; remanent magnetization; rock property; serpentinite; skarn https://www.scopus.com/inward/record.uri?eid=2-s2.0-80051905179&partnerID=40&md5=d67c6be1dbacbc3bfde402dc2973546d Cited by: 5 Frank Dietze Agnes Kontny article Reicherter2011217 The Lake Ohrid Basin in FYROM (Former Yugoslav Republic of Macedonia) and Albania meets all criteria of an active, seismic landscape: linear step-like fault scarps in the landscape and under water within the lake. Post-glacial (or Late Pleistocene) bedrock fault scarps at Lake Ohrid are long-lived expressions of repeated surface faulting in tectonically active regions, where erosion cannot outpace the fault slip. Other morphotectonic features are wind gaps, wineglass-shaped valleys and triangular facets, which are well preserved. Generally, the faults and fault scarps are getting younger towards the basin centre, as depicted on seismic and hydroacoustic profi les. Additionally, mass movement bodies within the lake and also onshore (rockfalls, landslides, sub-aquatic slides, homogenites, turbidites) are likely to have been seismically triggered. These morphotectonic observations are in line with focal mechanisms of earthquakes in the greater Lake Ohrid area. We investigated the neotectonic history and tectonic geomorphology of the Lake Ohrid Basin by means of an integrated multidisciplinary approach, using tectonic geomorphology and a variety of geophysical and remote sensing methods. © 2011 E. Article 2011 English 18601804 10.1127/1860-1804/2011/0162-0217 Zeitschrift der Deutschen Gesellschaft fur Geowissenschaften 162 217 – 234 2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-79960091763&doi=10.1127%2f1860-1804%2f2011%2f0162-0217&partnerID=40&md5=f5cb943db6ef5d97367681659e5aec29 Cited by: 28 Klaus Reicherter Nadine Hoffmann Katja Lindhorst Sebastian Krastel Tomás Fernández-Steeger Christoph Grützner Thomas Wiatr article Pérez2011407 This study presents limnological and morphological characteristics, physical and chemical properties of waters, and geochemistry of surface sediments for 63 aquatic ecosystems located on the karst Yucatán Peninsula and surrounding areas of Belize and the Guatemalan highlands and eastern lowlands. Our principal goal was to classify the aquatic systems based on their water variables. A principal component analysis (PCA) of the surface water chemistry data showed that a large fraction of the variance (29%) in water chemistry is explained by conductivity and major ion concentrations. The broad conductivity range, from 168 to 55,300 μS cm-1 reflects saline water intrusion affecting coastal aquatic environments, and the steep NW-S precipitation gradient, from ~450 to>3,200 mm year-1. Coastal waterbodies Celestún and Laguna Rosada displayed the highest conductivities. Minimum surface water temperatures of 21.6°C were measured in highland lakes, and warmest temperatures, up to 31.7°C, were recorded in the lowland waterbodies. Most lakes showed thermal stratification during the sampling period, with the exception of some shallow (<10 m) systems. Lakes Chichancanab, Milagros, and Bacalar displayed sulfate-rich waters. Waters of sinkholes had relatively high conductivities (<3,670 μS cm-1) and a broad range of δ18O values (-4.1 to +3.8%). Ca, HCO3, and SO4 dominated the waters of the lowland lakes, whereas Na was the dominant cation in highland lakes. Coastal aquatic ecosystems were dominated by Na and Cl. Cluster analysis based on surface water variables classified aquatic environments of the lowlands and highlands into three groups: (1) lowland lakes, ponds, wetlands, and coastal waterbodies (2) highland lakes, and (3) sinkholes and rivers. A broad trophic state gradient was recorded, ranging from the eutrophic Lake Amatitlán and the Timul sinkhole to oligotrophic Laguna Ayarza, with the highest water transparency (11.4 m). We used major and trace elements in surface sediments to assess pollution of waterbodies. Lakes Amatitlán, Atescatempa, El Rosario, Cayucón, Chacan-Lara, La Misteriosa, rivers Subín and Río Dulce, the wetland Jamolún, and the sinkhole Petén de Monos showed evidence of pollution and urban development. Their surface sediments displayed high concentrations of As, Cu, Fe, Ni, Pb, Se, Zn, and Zr, which suggest moderate to strong pollution. © Springer Science+Business Media B.V. 2010. Article 2011 English 00188158 10.1007/s10750-010-0552-9 Hydrobiologia 661 Kluwer Academic Publishers 407 – 433 1 Belize [Central America]; Guatemala [Central America]; Mexico [North America]; Yucatan Peninsula; hydraulic conductivity; karst; lake pollution; limnology; morphology; Neotropical Region; physicochemical property; pollution effect; principal component analysis; saline intrusion; surface water; trace element; urban development; water temperature https://www.scopus.com/inward/record.uri?eid=2-s2.0-79957921074&doi=10.1007%2fs10750-010-0552-9&partnerID=40&md5=094e24633a5ab3db9ac3940a6beea82e Cited by: 59 Liseth Pérez Rita Bugja Julia Lorenschat Mark Brenner Jason Curtis Philipp Hoelzmann Gerald Islebe Burkhard Scharf Antje Schwalb article CHENGRi-Hui_285 2011 Earth Science Frontiers 18 Earth Science Frontiers 285-328 6 Songliao Basin; SK1; Mingshui Formation; sedimentary facies; sedimentary sequence; cyclostratigraphy https://www.earthsciencefrontiers.net.cn/EN/abstract/article_4384.shtml ZHANG Shi-Gong CHENG Ri-Hui article xiao2011attempt 2011 Geoscience 25 401 3 MO Xiao-Qiao WANG Chao others article Lin2025 Article 2011 Geosciences 24 419-428 03 F. Tun C. Wang S. Zhang T. Yang X. Mo article Johnson2011103 We report a 150,000. year record of the abundance of biogenic silica (BSi) in drill cores from the northern and central basins of Lake Malawi. The periods of highest diatom burial at both sites occurred around 65-69 and 51-60. thousand years ago (ka) after the termination of prolonged, intense drought in the region. These peaks are believed to reflect elevated delivery of dissolved silica to the lake due to acceleration of chemical weathering in the drainage basin. The droughts that preceded these BSi depositional episodes occurred at precessional frequency, corresponding to times of minimum austral spring (or summer?) insolation in the region prior to 60. ka. Subsequent arid spells have not been as severe due to the reduced amplitude of precessional forcing as a result of the superimposed effect of eccentricity. However, biogenic silica records do not show significant sensitivity to precessional forcing. The BSi burial flux in the north basin displays strong millennial-scale variability since 50. ka, with peak values occurring during cold times in the Northern Hemisphere, as reflected in the Greenland ice core records. We observe no relationship between BSi and deposition of volcanic tephras in this system. The central basin core also displays millennial-scale variability in BSi abundance during the past 50. ky, of comparable magnitude to that in the north basin, but without systematic correlation to the north basin BSi or Greenland ice core records. In general, we conclude that BSi profiles from the north and (probably) south basins are more readily interpreted in terms of regional climate dynamics than are BSi profiles from more central locations in long, narrow tropical rift lakes. Diatom burial rates are suspected to be too influenced by silica limitations imposed by diatom production and burial in the upwelling systems at either end of these low-latitude lacustrine systems. © 2010 Elsevier B.V. 2011 English 00310182 10.1016/j.palaeo.2010.01.024 Palaeogeography, Palaeoclimatology, Palaeoecology 303 103-109 Large Lakes Observatory and Department of Geological Sciences, University of Minnesota Duluth, Duluth, MN 55812, United States 1-4 biogenic deposit; chemical weathering; diatom; drainage basin; ice core; lacustrine deposit; paleoclimate; sediment core; silica; tephra; tropical region, East Africa; East African Lakes; Lake Malawi, Bacillariophyta https://www.scopus.com/inward/record.uri?eid=2-s2.0-79953151026&doi=10.1016%2fj.palaeo.2010.01.024&partnerID=40&md5=778145b48a142be1462394462fd74e8a cited By 39 T.C. Johnson E.T. Brown J. Shi article Huguet20111289 The endorheic Lake Van in eastern Anatolia (Turkey) is the world's largest soda lake and it is an important site in paleoclimate studies to understand past continental conditions in western Asia. In order to gain further insights into the biomarker signatures in Lake Van's sediments we have analyzed particulate material in sediment traps deployed between August 2006 and July 2007. The biomarkers used were long chain alkenones (LCAs C37-C39, haptophyte lipids), isoprenoid glycerol dialkyl glycerol tetraethers (GDGTs, Archaea membrane lipids) and pigments (chlorins and fucoxanthin). The biomarker fluxes indicate a strong seasonality in export primary productivity and the phytoplankton community structure. The highest total mass and organic carbon fluxes were found in summer, coupled to strong stratification while the lowest mass fluxes occurred in winter at the time of water column mixing. With increasing temperatures in early spring, phytoplankton export productivity grew, coupled with an increase of total mass flux and organic carbon, which might be associated to enhanced nutrient input from snowmelt runoff. The percentage of C37:4 shows some correspondence with observed seasonal changes in Lake Van's stratification structure. We also evaluated the potential applicability of molecular temperature proxies derived from Archaea and haptophyte lipids. The use of the TEX86 proxy was precluded by low GDGT abundances. Estimated LCA temperatures were consistent with temperatures in the photic zone but no seasonality changes were observed despite the wide annual temperature range measured at Lake Van. © 2011 Elsevier Ltd. 2011 English 01466380 10.1016/j.orggeochem.2011.09.007 Organic Geochemistry 42 1289-1298 Institut de Ciència i Tecnologia Ambientals, Universitat Autònoma de Barcelona, 08193 Cerdanyola del Vallès, Catalonia, Spain; Eawag, Swiss Federal Institute of Aquatic Science and Technology, Department of Surface Water Research and Management, Ueberlandstrasse 133, 8600 Dubendorf, Switzerland; Department of Geography, Universitat Autònoma de Barcelona, 08193 Cerdanyola del Vallès, Catalonia, Spain; ICREA, Passeig Lluís Companys 23, 08010 Barcelona, Catalonia, Spain 11 Archaea; Biomarker flux; Chlorins; Eastern Anatolia; Fucoxanthin; Isoprenoids; Long chain alkenones; Membrane lipids; Organic carbon fluxes; Paleoclimate studies; Particulate materials; Photic zone; Phytoplankton community; Primary productivity; Seasonal changes; Seasonality; Snowmelt runoff; Soda lakes; Strong stratification; Temperature proxy; Temperature range; Total mass; Total mass flux; Water columns, Algae control; Anoxic sediments; Biomarkers; Glycerol; Lipids; Microorganisms; Organic carbon; Phytoplankton; Productivity; Sedimentology, Lakes, biomarker; community structure; isoprenoid; nutrient; organic carbon; paleoclimate; particulate matter; photic zone; phytoplankton; pigment; prokaryote; runoff; seasonality; sediment trap; snowmelt; stratification; temperature profile; water column, Lake Van; Turkey https://www.scopus.com/inward/record.uri?eid=2-s2.0-80855143724&doi=10.1016%2fj.orggeochem.2011.09.007&partnerID=40&md5=f768a0333e9183974a6ca44bb93efa87 cited By 23 C. Huguet S. Fietz M. Stockhecke M. Sturm F.S. Anselmetti A. Rosell-Melé article wei2011centimeter 2011 Earth Science Frontiers 18 195 6 GAO Wei-Feng WANG Pu-Jun CHENG Ri-Hui WANG Guo-Dong MO Xiao-Qiao TUN He-Yong WANG Shu-Hua LIANG Mo-Lin article pu2011centimeter 2011 Earth Science Frontiers 18 218 6 WANG Pu-Jun GAO Wei-Feng CHENG Ri-Hui WANG Guo-Dong TUN He-Yong MO Xiao-Qiao YANG Gan-Sheng HONG Zhong-Xin article guo2011centimeter 2011 Earth Science Frontiers 18 263 6 WANG Guo-Dong CHENG Ri-Hui WANG Pu-Jun GAO Wei-Feng WANG Cheng-Shan LIN Yan-An HUANG Qing-Hua article 2011 Petroleum Geology & Oilfield Development 30 31-34 4 Y. Dang article Wilson2011460 A series of gas hydrate development scenarios were created to assess the range of outcomes predicted for the possible development of the "Eileen" gas hydrate accumulation, North Slope, Alaska. Production forecasts for the "reference case" were built using the 2002 Mallik production tests, mechanistic simulation, and geologic studies conducted by the US Geological Survey. Three additional scenarios were considered: A "downside-scenario" which fails to identify viable production, an "upside-scenario" describes results that are better than expected. To capture the full range of possible outcomes and balance the downside case, an "extreme upside scenario" assumes each well is exceptionally productive.Starting with a representative type-well simulation forecasts, field development timing is applied and the sum of individual well forecasts creating the field-wide production forecast. This technique is commonly used to schedule large-scale resource plays where drilling schedules are complex and production forecasts must account for many changing parameters. The complementary forecasts of rig count, capital investment, and cash flow can be used in a pre-appraisal assessment of potential commercial viability.Since no significant gas sales are currently possible on the North Slope of Alaska, typical parameters were used to create downside, reference, and upside case forecasts that predict from 0 to 71 BM3 (2.5 tcf) of gas may be produced in 20 years and nearly 283 BM3 (10 tcf) ultimate recovery after 100 years.Outlining a range of possible outcomes enables decision makers to visualize the pace and milestones that will be required to evaluate gas hydrate resource development in the Eileen accumulation. Critical values of peak production rate, time to meaningful production volumes, and investments required to rule out a downside case are provided. Upside cases identify potential if both depressurization and thermal stimulation yield positive results. An "extreme upside" case captures the full potential of unconstrained development with widely spaced wells. The results of this study indicate that recoverable gas hydrate resources may exist in the Eileen accumulation and that it represents a good opportunity for continued research. © 2010 Elsevier Ltd. 2011 English 02648172 10.1016/j.marpetgeo.2010.03.007 Marine and Petroleum Geology 28 460-477 Ryder Scott Company, L.P, 621 17th Street, Suite 1550, Denver, CO 80293, United States; ASRC Energy Services, 3900 C Street, Suite 702, Anchorage, AK 99503, United States; US Geological Survey Denver Federal Center, MS-939 Box 25046, Denver, CO 80225, United States; RPS Energy Canada, 1400, 800 Fifth Ave. SW, Calgary, AB, T2P 3T6, Canada; National Energy Technology Laboratory, 3610 Collins Ferry Road, Morgantown, WV 26507, United States; West Virginia University, Department of Chemical Engineering, Morgantown, WV 26506, United States 2 Alaska North Slope; Capital investment; Cash flow; Changing parameter; Commonly used; Critical value; Decision makers; Depressurizations; Development scenarios; Field development; Gas-hydrate production; Hydrate accumulations; North Slope of Alaska; Production forecasting; Production forecasts; Production rates; Production test; Production volumes; Resource development; Thermal stimulation; US Geological Survey, Forecasting; Gases; Hydration; Investments; Rating, Gas hydrates, forecasting method; gas hydrate; gas production; hydrocarbon reservoir; modeling; resource development, Alaska; North Slope; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-78651467241&doi=10.1016%2fj.marpetgeo.2010.03.007&partnerID=40&md5=90e03f5482e5213a8dd05880bad7bac5 cited By 38 S.J. Wilson R.B. Hunter T.S. Collett S. Hancock R. Boswell B.J. Anderson article Heesakkers20112427 Article 2011 10.1007/s00024-011-0355-6 Pure and Applied Geophysics 168 2427 – 2449 12 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84857560807&doi=10.1007%2fs00024-011-0355-6&partnerID=40&md5=84b8bef564caef6cd55211055f6a4a32 Cited by: 29 V. Heesakkers S. Murphy D.A. Lockner Z. Reches article Elbra2011405 Petrophysical, in particular seismic velocity, measurements of the Outokumpu deep drill core (depth 2.5 km) have been carried out to characterize the geophysical nature of the Paleoproterozoic crustal section of eastern Finland and to find lithological and geophysical interpretations to the distinct crustal reflectors as observed in seismic surveys. The results show that different lithological units can be identified based on the petrophysical data. The density of the samples remained nearly constant throughout the drilled section. Only diopside-tremolite skarns and black schists exhibit higher densities. The samples are dominated by the paramagnetic behaviour with occasional ferromagnetic signature caused by serpentinitic rocks. Large variations in seismic velocities, both at ambient pressure and under in situ crustal conditions are observed. The porosity of the samples, which is extremely low, is either intrinsic by nature or caused by decompaction related to fracturing during the core retrieval. It is noteworthy that these microfractures have dramatically lowered the VP and VS values. From the measured velocities and density data we have calculated the seismic impedances, Young's modulus and Poisson's ratios for the lithological units of the Outokumpu section and from these data the reflection coefficients for the major lithological boundaries, evident in the surveyed section, were determined. The data show that the strong and distinct reflections visible in wide-angle seismic surveys are caused by interfaces between diopside-tremolite skarn and either serpentinites, mica schist or black schist. © 2010 The Authors Geophysical Journal International © 2010 RAS. Article 2011 English 1365246X 10.1111/j.1365-246X.2010.04845.x Geophysical Journal International 184 405 – 415 1 Finland; Ita Suomen; Outokumpu; Acoustic impedance; Core drilling; Core samples; Drills; Geological surveys; Lithology; Mica; Paramagnetism; Reflection; Seismic waves; Seismology; Silicate minerals; Structural geology; Velocity; Ambient pressures; Black schist; Body waves; Crustal structure; Density data; Drill core; Eastern Finland; In-situ; Laboratory measurements; Mica schists; Microfractures; Paleoproterozoic; Petrophysical; Petrophysical properties; Poisson's ratio; Reflection coefficients; Seismic impedance; Seismic surveys; Seismic velocities; Young's Modulus; acoustic property; body wave; crustal structure; geophysics; lithology; Poisson ratio; porosity; schist; seismic survey; seismic velocity; skarn; wave propagation; Young modulus; Acoustic wave propagation https://www.scopus.com/inward/record.uri?eid=2-s2.0-78650121773&doi=10.1111%2fj.1365-246X.2010.04845.x&partnerID=40&md5=9a4625b5c5d0d270f89d2fb2201682ff Cited by: 22; All Open Access, Bronze Open Access, Green Open Access Tiiu Elbra Ronnie Karlqvist Ilkka Lassila Edward Hæggström Lauri J. Pesonen article Ahonen2011151 Extensive hydrogeological studies on the Outokumpu Deep Drill Hole R2500, drilled in 2004-2005, have been carried out during both the drilling phase as well as the post-drilling period. The present paper introduces the main results and characteristics of deep fluids and gases in the 2516 m deep hole drilled into a Paleoproterozoic formation of metasediments, ophiolite-derived altered ultrabasic rocks and pegmatitic granite. The main hydrogeological experiments during drilling were the daily monitoring of drilling fluid electrical conductivity, pH, composition and consumption (loss) of drilling fluid, as well as targeted fluid sampling and hydraulic testing during drilling breaks with the drill stem method. Hydrogeological sampling of the drill hole water with a tube method has been carried out three times to up to 1500-2350 m depths in the post-drilling period, and undisturbed formation fluid was pumped for several weeks from a packer-isolated fracture system at 967 m. The loss of drilling water during drilling was very heavy in the uppermost 1000 m of the hole (1-4 m3 of water per 1 m of drilling), but it decreased to a low level (<1 m3/m) at lower depths, indicating that hydraulically conductive fractures are more frequent in the first kilometre of bedrock than beneath. The hydraulic testing carried out at approximately 500-m depth intervals in 40-70 m thick sections indicated a similar pattern of hydraulic conductivity decreasing with depth: about 7.5 · 10-6 m/s at 500 m, 5.3 · 10-7 m/s at 1000 m, and practically impermeable rock at deeper levels. The electrical conductivity of the drill hole fluid rapidly increased in the post-drilling period due to the discharge of saline water from several fracture systems, and was monitored with repeated down-hole logs. In the uppermost 1000 m, fluid salinity has been in a semi-stable condition since about 2006, but in the deeper parts of the hole electrical conductivity continued to gradually increase in 2008 and 2009, when the most recent downhole logs and fluid sample profiles were obtained. The fluids are Ca-Na-Cl fluids with elevated Mg concentrations at the depths of the ophiolite-derived rocks of the Outokumpu assemblage. The fluids contain abundant gases, with methane and nitrogen being the main components. The stable isotope compositions (δ2H, δ18O) of the saline fluids indicate that they are not meteoric fluids but probably result from long-term water-rock interaction. The results indicate distinct water bodies isolated in fracture zones with minimal hydraulic connections. Article 2011 English 978-952217152-8 07828535 Special Paper of the Geological Survey of Finland 2011 Kukkonen I.T. 151 – 168 51 Finland; Ita Suomen; Outokumpu; bedrock; borehole; deep drilling; electrical conductivity; groundwater; hydraulic conductivity; hydraulic fracture; hydrochemistry; hydrogeology; isotopic composition; magnesium; salt water; stable isotope https://www.scopus.com/inward/record.uri?eid=2-s2.0-80051901472&partnerID=40&md5=5cc788f3a2d251190d1a54d67196ae39 Cited by: 25 Lasse Ahonen Riikka Kietäväinen Nina Kortelainen Ilmo T. Kukkonen Arto Pullinen Taru Toppi Malin Bomberg Merja Itävaara Aura Nousiainen Mari Nyyssönen Marjo Öster article Ramachandran2011 A 3D seismic survey (Mallik 3D), covering 126 km2 in the Mackenzie Delta area of Canada's north, was conducted by industry in 2002. Numerous lakes and marine inundation create a complex near-surface structure in the permafrost terrain. Much of the near subsurface remains frozen but significant melt zones exist particularly from perennially unfrozen water bodies. This results in an irregular distribution of permafrost ice creating a complex pattern of low and high frequency near-surface velocity variations which induce significant traveltime distortions in surface seismic data. A high resolution 3D traveltime tomography study was employed to map the permafrost velocity structure utilizing first-arrival traveltimes picked from 3D seismic shot records. Approximately 900,000 traveltime picks from 3167 shots were used in the inversion. Tomographic inversion of the first-arrival traveltimes resulted in a smooth velocity model for the upper 200 m of the subsurface. Ray coverage in the model is excellent down to 200 m providing effective control for estimating velocities through tomographic inversion. Resolution tests conducted through horizontal and vertical checkerboard tests confirm the robustness of the velocity model in detailing small scale velocity variations. Well velocities were used to validate tomographic velocities. The tomographic velocities do not show systematic correlation with well velocities. The velocity model clearly images the permafrost velocity structure in lateral and vertical directions. It is inferred from the velocity model that the permafrost structure in the near subsurface is discontinuous. Extensions of surface water bodies in depth, characterized by low P-wave velocities, are well imaged by the velocity model. Deep lakes with unfrozen water, inferred from the tomographic velocity model, correlate with areas of strong amplitude blanking and frequency attenuation observed in processed reflection seismic stack sections. © 2011 Society of Exploration Geophysicists. 2011 English 00168033 10.1190/geo2010-0353.1 Geophysics 76 Society of Exploration Geophysicists B187-B198 The University of Tulsa, Department of Geosciences, Tulsa, OK, United States; Geological Survey of Canada, Ottawa, ON, Canada; Geological Survey of Canada, Calgary, AB, Canada; Geological Survey of Canada, Sidney, BC, Canada 5 Lakes; Permafrost; Seismic prospecting; Seismic waves; Seismology; Surface structure; Tomography, Case history; Complex near surfaces; Frequency attenuation; Low and high frequencies; Systematic correlation; Tomographic inversion; Travel time tomography; Velocity analysis, Velocity, arrival time; imaging method; P-wave; permafrost; seismic data; seismic survey; seismic tomography; three-dimensional modeling; travel time; velocity structure, Canada; Mackenzie Delta; Northwest Territories https://www.scopus.com/inward/record.uri?eid=2-s2.0-84857240045&doi=10.1190%2fgeo2010-0353.1&partnerID=40&md5=38faf51d9fbce456b2c238653d17b377 cited By 14 K. Ramachandran G. Bellefleur T. Brent M. Riedel S. Dallimore article Ross2011253 Article 2011 10.1016/j.jvolgeores.2010.07.018 Journal of Volcanology and Geothermal Research 201 253 – 271 1-4 https://www.scopus.com/inward/record.uri?eid=2-s2.0-79953040914&doi=10.1016%2fj.jvolgeores.2010.07.018&partnerID=40&md5=301e0f9249417fb361fdd3d5564bbf03 Cited by: 99 Pierre-Simon Ross Séverine Delpit Miguel J. Haller Karoly Németh Hugo Corbella article Chapligin20117242 Several techniques have been introduced in the last decades for the dehydration and release of O2 from biogenic silica (opal-A) for oxygen-isotope analysis. However, only one silica standard is universally available: a quartz standard (NBS28) distributed by the IAEA, Vienna. Hence, there is a need for biogenic silica working standards. This paper compares the existing methods of oxygen-isotope analyses of opal-A and aims to characterize additional possible working standards to calibrate the δ18O values of biogenic silica. For this purpose, an inter-laboratory comparison was organized. Six potential working standard materials were analysed repeatedly against NBS28 by eight participating laboratories using their specific analytical methods. The materials cover a wide range of δ18O values (+23 to +43‰) and include diatoms (marine, lacustrine), phytoliths and synthetically-produced hydrous silica. To characterize the proposed standards, chemical analyses and imaging by scanning electron microscopy (SEM) were also performed. Despite procedural differences at each laboratory, all methods are in reasonable agreement with a standard deviation (SD) for δ18O values between 0.3‰ and 0.9‰ (1σ). Based on the results, we propose four additional biogenic silica working standards (PS1772-8: 42.8‰; BFC: 29.0‰; MSG60: 37.0‰; G95-25-CL leaves: 36.6‰) for δ18O analyses, available on request through the relevant laboratories. © 2011 Elsevier Ltd. 2011 English 00167037 10.1016/j.gca.2011.08.011 Geochimica et Cosmochimica Acta 75 7242-7256 Alfred Wegener Institute (AWI) for Polar and Marine Research, Research Unit Potsdam and Bremerhaven, Telegrafenberg A43, D-14473 Potsdam, Germany; NERC Isotope Geosciences Laboratory (NIGL), British Geological Survey, Keyworth, Nottingham NG12 5GG, United Kingdom; Laboratory for Stable Isotope Science, Department of Earth Sciences, The University of Western Ontario (UWO), London, ON, N6A 5B7, Canada; CEREGE, CNRS, IRD, Université Aix-Marseille, Europôle de l'Arbois, BP 80, 13545 Aix-en-Provence Cedex 4, France; Department of Earth and Planetary Sciences, University of New Mexico (UNM), Northrop Hall, Albuquerque, NM 87131, United States; Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka 237-0061, Japan; Institute of Bio- and Geosciences, IBG-3: Agrosphere, Research Centre Jülich, D-52425 Jülich, Germany; Weizmann Institute of Science (WIS), Rehovot 76100, Israel; Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR, United Kingdom; School of Geography, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom; Department of Earth Sciences, University of Oxford, South Parks Road, Oxford OX1 3AN, United Kingdom 22 biogenic mineral; calibration; comparative study; isotopic analysis; isotopic composition; laboratory method; opal; oxygen isotope; scanning electron microscopy, Bacillariophyta https://www.scopus.com/inward/record.uri?eid=2-s2.0-80055028352&doi=10.1016%2fj.gca.2011.08.011&partnerID=40&md5=5ed839244f354bcd38a40a4904e6a0a4 cited By 67 B. Chapligin M.J. Leng E. Webb A. Alexandre J.P. Dodd A. Ijiri A. Lücke A. Shemesh A. Abelmann U. Herzschuh F.J. Longstaffe H. Meyer R. Moschen Y. Okazaki N.H. Rees Z.D. Sharp H.J. Sloane C. Sonzogni G.E.A. Swann F. Sylvestre J.J. Tyler R. Yam article 2011 Journal of Geological Society of India 77 488-490 https://indianjournalofcapitalmarkets.com/index.php/jgsi/article/view/58204/45478 H. Gupta S. Nayak Y.J. Bhaskar Rao R.K. Chadha B.K. Bansal D. Srinagesh N. Purnachandra Rao S. Roy article Kagan2011 A comprehensive multisite paleoseismic archive of the late Holocene Dead Sea basin (past 2500 years) is established by constructing two age-depth chronological models of two sedimentary sections exposed at the retreating shores of the modern Dead Sea. Two new paleoseismic study sites studied are the Ein Feshkha Nature Reserve outcrop located at the northern part of the basin and close to an active underwater transverse fault and the east Ze'elim Gully outcrop at the southern part of the basin. Age-depth regression models are calculated for these sections based on atmospheric radiocarbon ages of short-lived organic debris calibrated with a Bayesian model. The uncertainties on individual model ages are smaller than 100 years. The new chronological records are compared to a laminae-counting study of the Ein Gedi core (Migowski et al., 2004) located at the central Dead Sea basin. The Ein Feshkha outcrop yielded the largest number of seismites in the studied time interval (n = 52), while lower numbers of seismites are recovered from the Ze'elim outcrop and Ein Gedi core (n = 15 and 36, respectively). The seismites show no strong dependence on the limnological-sedimentological conditions in the particular sampling sites (they coappear in both shallow and deep water environments and in different sedimentary facies). During time intervals when the chronologies are comparable it appears that the number of seismites is significantly larger in the northern part of the basin (Ein Gedi and Ein Feshkha). Seismic quiescence intervals are apparent at all three sites from 2nd-4th century A.D. and at 500-150 B.C. at Ze'elim and Ein Gedi. Several synchronous seismites appear in all sections (termed here the intrabasin seismites (IBS)). Among them: 1927, 1293, 1202/1212, 749, 551, 419, and 33 A.D. and 31 and mid-2nd century B.C. The recurrence time of the IBS from the 2nd century B.C. to the 14th century A.D. is ∼200 years, compared with ∼100 years for all earthquakes. On a diagram of epicentral distance versus magnitude, historic earthquakes that are correlated with IBS plot in a field of high local intensity. The farther and stronger IBS earthquakes require lower local intensities to be recorded. This study demonstrates that a painstaking effort is still needed for unraveling the seismic history of the Dead Sea basin. The results also indicate that such a study will likely be highly rewarding. Copyright 2011 by the American Geophysical Union. 2011 English 21699313 10.1029/2010JB007452 Journal of Geophysical Research: Solid Earth 116 Blackwell Publishing Ltd Institute of Earth Sciences, Hebrew University of Jerusalem, Edmond Safra Campus, Givat Ram, Jerusalem 91904, Israel; Geological Survey of Israel, 30 Malkhe Israel St., 95501, Jerusalem, Israel; Bernard Price Institute for Palaeontological Research, University of the Witwatersrand, Johannesburg, South Africa; Steinmann Institute for Geology, Mineralogy and Palaeontology, Bonn, Germany; Forschungsstelle für Palobotanik Am Geologisch-Palontologischen Institut, Westflische Wilhelms-Universitt Münster, Müenster, Germany 4 Bayesian analysis; earthquake epicenter; earthquake intensity; earthquake magnitude; fault; geochronology; Holocene; limnology; outcrop; paleoseismicity; radiocarbon dating; sedimentology; seismite, Dead Sea https://www.scopus.com/inward/record.uri?eid=2-s2.0-79955449342&doi=10.1029%2f2010JB007452&partnerID=40&md5=a03723d82055830464e29df32f9dfa66 cited By 58 E. Kagan M. Stein A. Agnon F. Neumann article Brown2011120 Sediment records from the northern basin of Lake Malawi provide a means of evaluating the lake basin's response to climate change over the past 75. ky, notably to increased precipitation at the terminations of droughts. Transitions from drier to wetter conditions provide an opportunity to evaluate the system's response to climate shifts. Upon termination of drought episodes at 62 and 72. ka, enhanced precipitation and an associated increase in streampower led to enhanced physical erosion and landscapes were flooded by rising lake waters. These processes appear to have left their mark in the sedimentary record, bringing about a spike of deposition of organic matter (probably of terrestrial origin) at times of increased rainfall. This was immediately followed by a period of deposition of chemically-weathered material that had been retained on the landscape during arid times and mobilized in response to increased precipitation. After this altered material was removed (perhaps a thousand years after the transition to wetter conditions), fresher material, richer in soluble elements including nutrients, was exposed to chemical weathering, leading to substantial diatom blooms. The lag between the onset of wetter conditions and the diatom blooms is inconsistent with significant storage of bioavailable silica in soils in this system. However, biological cycling of silica, including formation and dissolution of phytoliths, may have played a role in mobilization of the silica necessary for the diatom productivity. © 2010 Elsevier B.V. 2011 English 00310182 10.1016/j.palaeo.2010.01.038 Palaeogeography, Palaeoclimatology, Palaeoecology 303 120-125 Large Lakes Observatory, University of Minnesota Duluth, Duluth, MN 55812, United States; Department of Geological Sciences, University of Minnesota Duluth, Duluth, MN 55812, United States 1-4 biogenic deposit; chemical weathering; climate change; diatom; dissolution; drought; erosion rate; flooding; lacustrine deposit; lake water; paleoclimate; phytolith; precipitation (climatology); silica; weathering, East African Lakes; Lake Malawi, Bacillariophyta https://www.scopus.com/inward/record.uri?eid=2-s2.0-79953154159&doi=10.1016%2fj.palaeo.2010.01.038&partnerID=40&md5=8f5c88c5b5a18c25972c1d5f1f1a37d9 cited By 34 E.T. Brown article Marks2011 Granoblastic hornfels identified in cuttings from the Reykjanes seawater-dominated hydrothermal system contains secondary pyroxene, anorthite, and hornblendic amphibole in locally equilibrated assemblages. Granoblastic assemblages containing secondary orthopyroxene, olivine, and, locally, cordierite and spinel occur within groups of cuttings that show dominantly greenschist facies hydrothermal alteration. Granoblastic plagioclase ranges continuously in composition from An54 to An96, in contrast with relict igneous plagioclase that ranges from An42 to An80. Typical hydrothermal clinopyroxene compositions range from Wo49En3Fs48 to Wo 53En30Fo17; clinopyroxene from the granoblastic grains is less calcic with an average composition of Wo48En 27Fs25. The hornfels is interpreted to form during contact metamorphism in response to dike emplacement, resulting in local recrystallization of previously hydrothermally altered basalts. Temperatures of granoblastic recrystallization estimated from the 2-pyroxene geothermometer range from 927°C to 967°C. Redox estimates based on the 2-oxide oxybarometer range from log fO2 of -13.4 to -15.9. Granoblastic hornfels comprised of clinopyroxene, orthopyroxene, and calcic plagioclase have been described in a number of ancient hydrothermal systems from the conductive boundary layer between the hydrothermal system and the underlying magma source, most notably in Integrated Ocean Drilling Program Hole 1256D, Ocean Drilling Program Hole 504B, and in the Troodos and Oman ophiolites. To our knowledge, this is the first evidence of high-grade contact metamorphism from an active geothermal system and the first description of equilibrated amphibole-absent pyroxene hornfels facies contact metamorphism in any mid-ocean ridge (MOR) hydrothermal system. This contribution describes how these assemblages develop through metamorphic reactions and allows us to predict that higher-temperature assemblages may also be present in MOR systems. Copyright 2011 by the American Geophysical Union. 2011 English 15252027 10.1029/2011GC003569 Geochemistry, Geophysics, Geosystems 12 Blackwell Publishing Ltd Department of Geology, University of California, Davis, CA 95616, United States; Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA 94550, United States 8 Feldspar; Geothermal fields; Geothermal prospecting; Hydraulic structures; Igneous rocks; Oceanography; Offshore oil wells; Olivine; Recrystallization (metallurgy); Seawater; Submarine geology, alteration; Average composition; Clinopyroxenes; contact metamorphism; Fluid-rock interaction; Geothermal systems; Geothermometers; Greenschist; Hydrothermal alterations; Hydrothermal system; hydrothermal systems; Hydrothermally; Magma sources; Metamorphic reactions; Mid-ocean ridges; Mid-oceanic ridges; Ocean drilling programs; Oman ophiolite; Orthopyroxene, Metamorphic rocks, clinopyroxene; contact metamorphism; fluid-structure interaction; geothermal system; geothermometry; greenschist facies; hydrothermal alteration; hydrothermal system; mid-ocean ridge; Ocean Drilling Program; P-T conditions; recrystallization; spreading center, Atlantic Ocean; Reykjanes Ridge https://www.scopus.com/inward/record.uri?eid=2-s2.0-84860410767&doi=10.1029%2f2011GC003569&partnerID=40&md5=56e336775dfd812171028e9546d996f3 cited By 19 N. Marks P. Schiffman R.A. Zierenberg article Stone201151 Analysis of sedimentary diatom assemblages (10 to 144. ka) form the basis for a detailed reconstruction of the paleohydrography and diatom paleoecology of Lake Malawi. Lake-level fluctuations on the order of hundreds of meters were inferred from dramatic changes in the fossil and sedimentary archives. Many of the fossil diatom assemblages we observed have no analog in modern Lake Malawi. Cyclotelloid diatom species are a major component of fossil assemblages prior to 35. ka, but are not found in significant abundances in the modern diatom communities in Lake Malawi. Salinity- and alkalinity-tolerant plankton has not been reported in the modern lake system, but frequently dominant fossil diatom assemblages prior to 85. ka. Large stephanodiscoid species that often dominate the plankton today are rarely present in the fossil record prior to 31. ka. Similarly, prior to 31. ka, common central-basin aulacoseiroid species are replaced by species found in the shallow, well-mixed southern basin. Surprisingly, tychoplankton and periphyton were not common throughout prolonged lowstands, but tended to increase in relative abundance during periods of inferred deeper-lake environments. A high-resolution lake level reconstruction was generated by a principle component analysis of fossil diatom and wet-sieved fossil and mineralogical residue records. Prior to 70. ka, fossil assemblages suggest that the central basin was periodically a much shallower, more saline and/or alkaline, well-mixed environment. The most significant reconstructed lowstands are ~. 600. m below the modern lake level and span thousands of years. These conditions contrast starkly with the deep, dilute, dysaerobic environments of the modern central basin. After 70. ka, our reconstruction indicates sustained deeper-water environments were common, marked by a few brief, but significant, lowstands. High amplitude lake-level fluctuations appear related to changes in insolation. Seismic reflection data and additional sediment cores recovered from the northern basin of Lake Malawi provide evidence that supports our reconstruction. © 2010 Elsevier B.V. 2011 English 00310182 10.1016/j.palaeo.2010.01.012 Palaeogeography, Palaeoclimatology, Palaeoecology 303 51-70 Department of Geosciences, University of Nebraska-Lincoln, 214 Bessey Hall, Lincoln, NE 68588, United States; Department of Ecology and Environmental Science, Umeå University, Umeå, 901 87, Sweden; Department of Geosciences, University of Arizona, Gould-Simpson Building #77, 1040 E 4th St., Tucson, AZ, 85721, United States 1-4 deep water; diatom; fossil assemblage; fossil record; lake level; paleoclimate; paleoecology; paleohydrology; periphyton; Pleistocene; seismic reflection, East Africa; East African Lakes; Lake Malawi, Bacillariophyta https://www.scopus.com/inward/record.uri?eid=2-s2.0-79953161494&doi=10.1016%2fj.palaeo.2010.01.012&partnerID=40&md5=fdc880d49ab74cd71939258d81222f62 cited By 59 J.R. Stone K.S. Westover A.S. Cohen article Woltering201193 We present a TEX86-derived surface water temperature record for Lake Malawi that provides the first continuous continental record of temperature variability in the continental tropics spanning the past ~74kyr with millennial-scale resolution. Average temperature during Marine Isotope Stage (MIS) 5A was 26.5°C, with a range from 25.7 to 27.3°C, comparable to Holocene temperatures. MIS 4 was a relatively cold period with temperatures generally decreasing from 25.5°C at 68ka to a minimum of 20°C at ~60ka, 1.5-2°C colder than the Last Glacial Maximum (LGM). Termination of MIS 4 is characterized by a rapid increase of 3-4°C in only ~0.5kyr. Temperatures were relatively stable throughout MIS 3 at the resolution of this study, with an average of 23.8°C and a range from 25.1 to 22.9°C. The lack of millennial-scale temperature variability during MIS 3 suggests that Lake Malawi's documented response to the bipolar seesaw (Brown et al., 2007) is not reflected in its thermal history. Our temperature estimates for the LGM and Holocene are consistent with a previously published TEX86 record from Lake Malawi with a temperature of ~22.6°C for the LGM, ~25-26°C in the mid Holocene and ~25-28 for the late Holocene. In general the present extended TEX86 record indicates that temperature variability in tropical East Africa during late MIS 5 and MIS 4 was as great as that associated with the deglaciation and Holocene. A decrease in Southern Hemisphere insolation between 70 and 60ka may have played an important role in forcing temperatures during MIS 4, but after 60ka other factors, such as the extent of the polar ice sheets, or atmospheric CO2 may have forced temperature in tropical Africa to a greater extent than local summer insolation. © 2010. 2011 English 00310182 10.1016/j.palaeo.2010.02.013 Palaeogeography, Palaeoclimatology, Palaeoecology 303 93-102 Large Lakes Observatory, University of Minnesota Duluth, 10 University Dr., Duluth, MN 55812, United States; Department of Chemistry and Biochemistry, University of Minnesota Duluth, 10 University Dr., Duluth, MN 55812, United States; Department of Geological Sciences, University of Minnesota Duluth, 10 University Dr., Duluth, MN 55812, United States; NIOZ Royal Netherlands Institute for Sea Research, Department of Marine Organic Biogeochemistry, PO Box 59, 1790 AB, Den Burg, Texel, Netherlands; Department of Geosciences, Utrecht University, Budapestlaan 4, 3584 CD Utrecht, Netherlands 1-4 deglaciation; Holocene; ice sheet; lacustrine deposit; Last Glacial Maximum; marine isotope stage; surface water; temperature inversion; temperature profile; tropical region; water temperature, East Africa; East African Lakes; Lake Malawi https://www.scopus.com/inward/record.uri?eid=2-s2.0-79953161143&doi=10.1016%2fj.palaeo.2010.02.013&partnerID=40&md5=08f66321f80ab6e892bf79064d91235b cited By 59 M. Woltering T.C. Johnson J.P. Werne S. Schouten J.S. Sinninghe Damsté article Juschus2011441 Lake El'gygytgyn is situated in a 3.6. Ma old impact crater in northeastern Siberia. Presented here is a reconstruction of the Quaternary lake-level history as derived from sediment cores from the southern lake shelf. There, a cliff-like bench 10. m below the modern water level has been investigated. Deep-water sediments on the shelf indicate high lake levels during a warm Mid-Pleistocene period. One period with low lake level prior to Marine Oxygen Isotope Stage (MIS) 3 has been identified, followed by a period of high lake level (10. m above present). In the course of MIS 2 the lake level dropped to -10 m At the end of MIS 2 the bench was formed and coarse beach sedimentation occurred. Subsequently, the lake level rose rapidly to the Holocene level. Changes in water level are likely linked to climate variability. During relatively temperate periods the lake becomes free of ice in summer. Strong wave actions transport sediment parallel to the coast and towards the outlet, where the material tends to accumulate, resulting in lake level rise. During cold periods the perennial lake ice cover hampers any wave activity and pebble-transport, keeping the outlet open and causing the lake level to drop. © 2011 University of Washington. 2011 English 00335894 10.1016/j.yqres.2011.06.010 Quaternary Research 76 441-451 Institute of Applied Geoscience, Technische Universität Berlin, Ackerstraße 76, Sek ACK 1-1, 13355 Berlin, Germany; Arctic and Antarctic Research Institute, Bering Street, 199397 St. Petersburg, Russian Federation; Alfred Wegener Institute for Polar and Marine Research, Telegrafenberg, 14471 Potsdam, Germany; Institute of Geological Sciences, Universität Bern, Baltzerstrasse 1+3, 3012 Bern, Switzerland; Institute of Geology and Mineralogy, University of Cologne, Zuelpicher Strasse 49a, 50674 Cologne, Germany; Department of Physical Geography and Quaternary Geology, Stockholm University, 10691 Stockholm, Sweden 3 Climate variability; Deep-water sediments; Holocenes; Ice cover; Impact craters; Lake levels; Lake-level changes; Late quaternary; Marine oxygen isotopes; Sediment core; SIBERIA; Siberian Arctic; Strong waves; Wave activity, Anoxic sediments; Climatology; Isotopes; Sedimentology; Water levels, Lakes, ice cover; lake level; oxygen isotope; Quaternary; sediment core; sediment transport; sedimentation; water level, Chukchi; Elgygytgyn Lake; Russian Federation; Serbia https://www.scopus.com/inward/record.uri?eid=2-s2.0-82455164294&doi=10.1016%2fj.yqres.2011.06.010&partnerID=40&md5=58fc6a3e73f39f207e70f8cebbb359c6 cited By 23 O. Juschus M. Pavlov G. Schwamborn F. Preusser G. Fedorov M. Melles article Lyons201120 Lake Malawi contains a long continuous sedimentary record of climate change in the southern hemisphere African tropics. We develop a stratigraphic framework of this basin over the last ~. 150 ka by integrating several vintages of seismic-reflection data with recently acquired drill cores. In the seismic-reflection data set, we document three lake-level cycles where progradational delta seismic facies and erosional truncation surfaces mark the basal boundary of each sequence. The clinoform packages and their down-dip, time-equivalent surfaces can be mapped throughout each basin, where each major lowstand surface was followed by a transgression and highstand. On several occasions, lake level dropped as much as 500 m below present lake level (BPLL) in the North Basin and 550 m BPLL in the Central Basin, resulting in a 97% reduction of water volume and 89% reduction of water surface area relative to modern conditions. Evidence for these lake-level fluctuations in the drill cores includes major changes in saturated bulk density, natural gamma ray values, and total organic carbon. During lowstands, density values doubled, while total organic carbon values dropped from ~. 5% to 0.2%. Coarse-grained sediment and organic matter flux into the basin were higher during transgressions, when precipitation, runoff, sediment supply, and nutrient input were high. This sedimentation pattern is also observed in seismic-reflection profiles, where coarse-grained seismic facies occur at the bases of sequences, and in the drill-core data where the highest total organic carbon values are observed immediately above lowstand surfaces. © 2009 Elsevier B.V. 2011 English 00310182 10.1016/j.palaeo.2009.04.014 Palaeogeography, Palaeoclimatology, Palaeoecology 303 20-37 Department of Earth Sciences, Syracuse University, 204 Heroy Geology Laboratory, Syracuse, NY 13244, United States; Chevron Corporation, 6001 Bollinger Canyon Road, San Ramon, CA 94583, United States; Newfield Exploration Company, 363 North Sam Houston Parkway East, Suite 2020, Houston, TX 77060, United States 1-4 data set; lake level; paleoclimate; sedimentary sequence; sedimentation rate; seismic reflection; seismic stratigraphy; Southern Hemisphere; surface water; total organic carbon, East Africa; East African Lakes; Lake Malawi https://www.scopus.com/inward/record.uri?eid=2-s2.0-79953153752&doi=10.1016%2fj.palaeo.2009.04.014&partnerID=40&md5=b288c7083c6e2bde25d429357b68ae16 cited By 93 R.P. Lyons C.A. Scholz M.R. Buoniconti M.R. Martin article Meyer20112312 The transport mechanism of suevite particles during impact cratering is poorly understood and was studied at the 15 Ma Ries crater in southern Germany. Two emplacement modes of suevite deposits are generally discussed: (1) fallback of plume material into the crater and its periphery upon collapse of an ejecta plume; and (2) horizontal transport of ejected material, akin to emplacement of pyroclastic deposits erupting from volcanic centers. In order to differentiate between the two emplacement modes of suevite deposition, we analyzed the shape fabrics of suevite components from two localities outside the Ries crater by fitting shape-fabric ellipsoids to measured shape-fabric ellipses and by applying high-resolution, X-ray- computed tomography to analyze the threedimensional shape and orientation of the suevite particles. We show that the preferred orientation of long axes of elongate particles is disposed either radially or concentrically with respect to the crater center. Our observations indicate that suevite material was not only derived from an ejecta plume, but was transported by lateral flow under viscous conditions upon fallback. This flow regime resembles that known from pyroclastic flows. © 2011 Geological Society of America. 2011 10.1130/B30393.1 Bulletin of the Geological Society of America 123 2312-2319 Museum of Natural History Berlin, Leibniz Institute at the Humboldt University Berlin, Invalidenstrasse 43, 10115 Berlin, Germany; Université du Québec à Montréal, Département des Sciences de la Terre et de l'Atmosphère, CP 8888, Centre-Ville, Montréal, QC H4A 1N4, Canada; McMaster University Hamilton, School of Geography and Earth Sciences and Origins Institute, 1280 Main Street West, Hamilton, ON L8S 4K1, Canada 11-12 https://www.scopus.com/inward/record.uri?eid=2-s2.0-80055097141&doi=10.1130%2fB30393.1&partnerID=40&md5=04f3f34f53eab5788530a98b8628b71a cited By 20 C. Meyer M. Jébrak D. Stöffler U. Riller article Bradbury2011131 We characterize the lithology and structure of the spot core obtained in 2007 during Phase 3 drilling of the San Andreas Fault Observatory at Depth (SAFOD) in order to determine the composition, structure, and deformation processes of the fault zone at 3. km depth where creep and microseismicity occur. A total of approximately 41. m of spot core was taken from three separate sections of the borehole; the core samples consist of fractured arkosic sandstones and shale west of the SAF zone (Pacific Plate) and sheared fine-grained sedimentary rocks, ultrafine black fault-related rocks, and phyllosilicate-rich fault gouge within the fault zone (North American Plate). The fault zone at SAFOD consists of a broad zone of variably damaged rock containing localized zones of highly concentrated shear that often juxtapose distinct protoliths. Two zones of serpentinite-bearing clay gouge, each meters-thick, occur at the two locations of aseismic creep identified in the borehole on the basis of casing deformation. The gouge primarily is comprised of Mg-rich clays, serpentinite (lizardite ± chrysotile) with notable increases in magnetite, and Ni-Cr-oxides/hydroxides relative to the surrounding host rock. The rocks surrounding the two creeping gouge zones display a range of deformation including fractured protolith, block-in-matrix, and foliated cataclasite structure. The blocks and clasts predominately consist of sandstone and siltstone embedded in a clay-rich matrix that displays a penetrative scaly fabric. Mineral alteration, veins and fracture-surface coatings are present throughout the core, and reflect a long history of syn-deformation, fluid-rock reaction that contributes to the low-strength and creep in the meters-thick gouge zones. © 2011 Elsevier B.V. 2011 English 0012821X 10.1016/j.epsl.2011.07.020 Earth and Planetary Science Letters 310 131-144 Geology Department, Utah State University, Logan, UT 84321-4505, United States; Center for Tectonophysics, Department of Geology and Geophysics, Texas A and M University, College Station, TX 77843, United States; Department of Earth and Atmospheric Sciences, St. Louis University, St. Louis, MO 63108, United States 1-2 Casing deformation; Cataclasite; Clay gouges; Deformation process; During phase; Fault gouge; Fault zone; Fault-related rocks; Fluid-rock interaction; Host rocks; Internal structure; Lizardite; matrix; Microseismicity; North American; Pacific plates; Protoliths; SAFOD; San Andreas Fault; Serpentinite; Siltstones; Ultrafine; Whole-rock geochemistry, Buildings; Coatings; Creep; Iron ores; Kaolinite; Lithology; Minerals; Observatories; Plates (structural components); Rock drilling; Rocks; Sandstone; Sedimentology; Serpentine, Structural geology, borehole; creep; deformation; drilling; fault gouge; fault zone; host rock; lithology; observatory; Pacific plate; San Andreas Fault; sandstone; seismicity; shale https://www.scopus.com/inward/record.uri?eid=2-s2.0-80054076681&doi=10.1016%2fj.epsl.2011.07.020&partnerID=40&md5=d9df595952a680034a6df5ac1be44f94 cited By 61 K.K. Bradbury J.P. Evans J.S. Chester F.M. Chester D.L. Kirschner conference Behseresht20113797 The descent of the base of gas hydrate stability zone (BGHSZ) through gas accumulated in a sediment is analyzed. A mechanistic model enables estimating hydrate saturation from initial distribution of gas phase saturation in sediment with known grain size distribution. The initial gas phase saturation is estimated from the profile of capillary entry-pressure with depth. The latter is estimated from grain size variations. A mechanistic model is proposed to determine the relative rates of methane and water transport into the HSZ during hydrate formation. The gas accumulation is assumed to be isolated so that methane transport occurs only within it. If water transport occurs only by co-current flow of gaseous and aqueous phases up to the hydrate stability zone (HSZ), it is not possible to create large hydrate saturations from large initial gas saturations due to limitations on water flux imposed by typical relative permeability curves. Thus the observed large hydrate saturations, such as that observed in Mt. Elbert, Alaska and Mallik, NW Territories and deep Indian Ocean, above the BGHSZ suggest another form of water flow: water moves down through accumulated hydrate from above. This requires the aqueous phase to remain connected within the hydrate-bearing sediment. The ratio of aqueous phase permeability in the hydrate-bearing sediment to the aqueous phase relative permeability at residual gas saturation determines hydrate saturation profile. The model is validated against field data from a hydrate-bearing sand unit in Mt. Elbert. Copyright 2011, Society of Petroleum Engineers. 2011 English 9781618392657 10.2118/147221-ms Proceedings - SPE Annual Technical Conference and Exhibition 5 Society of Petroleum Engineers (SPE) 3797-3810 University of Texas at Austin, United States Flow of water; Gas permeability; Gases; Grain size and shape; Hydration; Methane; Sediments, Capillary entry pressure; Gas hydrate saturations; Gas hydrate stability zones; Grain size distribution; Hydrate bearing sediments; Relative permeability; Relative permeability curves; Residual gas saturation, Gas hydrates https://www.scopus.com/inward/record.uri?eid=2-s2.0-84856736126&doi=10.2118%2f147221-ms&partnerID=40&md5=ccac06f06dd5100991d42e83275c3745 cited By 3 J. Behseresht S. Bryant conference Shervais2011995 The Snake River volcanic province (SRP) overlies a thermal anomaly that extends deep into the mantle; it represents one of the highest heat flow provinces in North America, and an area with the highest calculated geothermal gradients. This makes the SRP one of the potentially highest producing geothermal districts in the United States. Elevated heat flow is typically highest along the margins of the topographic Snake River Plain and lowest along the axis of the plain, where thermal gradients are suppressed by the Snake River aquifer. Beneath this aquifer, however, thermal gradients rise again and may tap even higher heat flows associated with the intrusion of mafic magmas into a geophysically-imaged mid-crustal sill complex. The primary goal of this project is to evaluate geothermal potential in three distinct settings: (1) the high sub-aquifer geothermal gradient associated with the intrusion of mafic magmas and the release of crustal fluids from the associated wall rocks, (2) the valley-margin settings where surface heat flow may be driven by the up-flow of hot fluids along buried caldera ring-fault complexes, and (3) a more traditional fault-bounded basin with thick sedimentary cover. All settings are found within the central or western Snake River Plain and represent previously untested targets for geothermal exploration. Our first drill site tests the extent of geothermal resources along the axis of the plain, beneath the Snake River aquifer, in an area where elevated groundwater temperatures imply a significant flux of conductive or advective heat flow from below. Our second drill site assesses the geothermal potential of up-flow zones along a buried caldera margin, in an area of known geothermal potential (Twin Falls geothermal district). Further studies will include seismic reflection-refraction surveys, gravity-magnetic surveys, and downhole geophysical logs. 2011 English 9781618394828 01935933 Transactions - Geothermal Resources Council 35 2 995-1003 Department of Geology, Utah State University, Logan, UT, United States; Department of Geological Sciences, Brigham Young University, Provo, UT, United States; Department of Physics, University of Alberta, Edmonton, AB, Canada; Center for Geophysical Investigation of the Shallow Subsurface, Boise State University, Boise, ID, United States; Roy Huffington Department of Earth Sciences, Southern Methodist University, Dallas, TX, United States; US Geological Survey, Menlo Park, CA, United States Geothermal; Hot spot; Idaho; Rhyolite; Snake river plains; Yellowstones, Aquifers; Basalt; Drills; Geothermal fields; Geothermal wells; Heat transfer; Innovation; Rivers; Thermal gradients, Geothermal prospecting https://www.scopus.com/inward/record.uri?eid=2-s2.0-84860852919&partnerID=40&md5=df2929e80edeed00f028886cf7913fb9 cited By 13 J.W. Shervais J.P. Evans E.J. Christiansen L.M. Liberty D.D. Blackwell J.M. Glen J.E. Kessler K.E. Potter M.M. Jean C.J. Sant T.G. Freeman article Pérez201159 We inferred late Pleistocene and early Holocene (24-10 ka BP) environmental conditions in and around Lago Petén Itzá,Guatemala from ostracode remains in the lake sediments. Multivariate statistics were run on autecological information for 29 extant ostracode species collected in 63 aquatic ecosystems on the Yucatán Peninsula along a steep, increasing NW-S precipitation gradient and across a large altitudinal range. Conductivity and water depth are the most important factors that shape ostracode communities. Transfer functions were developed and applied to fossil ostracode assemblages in a ~76-m sediment core (PI-6, ~85 ka) taken in 71 m of water from Lago Petén Itzá, to infer past shifts in conductivity and water level. Results suggest climate was cold and wet during the Last Glacial Maximum (LGM). Alternating dry and wet conditions characterized the deglacial. Early Holocene climate was warmer and wetter. The LGM was characterized by low ostracode species richness (4 spp.) and abundance (<940 valves g-1), dominance of benthic over nektobenthic taxa, abundant Physocypria globula, conductivity as low as 190 μS cm-1, and clay-rich sediments with relatively high total organic carbon and low C/N ratios (<14), suggesting relatively deeper water at the core site associated with abundant precipitation. Greatest water depth at the core site during the LGM occurred late in the period and was ~50 m. The deglacial was characterized by drier conditions, higher ostracode species richness (6 spp.) and abundances up to 18,115 valves g-1, dominance of nektobenthic species, and presence of shallow-water and littoral-zone indicators such as Heterocypris punctata and Strandesia intrepida, conductivity up to 550 μS cm-1, C/N ratios as high as 37, and gypsum deposition. Lowest inferred lake depth at the core site during the deglacial was ~20 m. The early Holocene was characterized by high numbers of ostracode remains, up to 25,500 valves g-1, and the presence of L. opesta and P. globula. Cytheridella ilosvayi was absent from late Pleistocene sediments, suggesting it colonized northern Central America during the Holocene. © 2011 Springer Science+Business Media B.V. Article 2011 English 09212728 10.1007/s10933-011-9514-0 Journal of Paleolimnology 46 59 – 74 1 Guatemala [Central America]; Lake Peten Itza; Peten; Heterocypris punctata; Ostracoda; Physocypria; abundance; aquatic ecosystem; benthos; carbon; community structure; crustacean; deglaciation; dominance; environmental change; environmental conditions; Holocene; intertidal environment; lacustrine deposit; Last Glacial Maximum; lowland environment; multivariate analysis; Neotropical Region; nitrogen; organic carbon; precipitation intensity; sediment analysis; shallow water; species richness; transfer function; water depth https://www.scopus.com/inward/record.uri?eid=2-s2.0-79957922065&doi=10.1007%2fs10933-011-9514-0&partnerID=40&md5=9445fc9e154af1fb35aaa1c62ad05e15 Cited by: 33 Liseth Pérez Peter Frenzel Mark Brenner Jaime Escobar Philipp Hoelzmann Burkhard Scharf Antje Schwalb article Pollitz20111420 High-frequency and full waveform synthetic seismograms on a 3-D laterally heterogeneous earth model are simulated using the theory of coupled normal modes. The set of coupled integral equations that describe the 3-D response are simplified into a set of uncoupled integral equations by using the Born approximation to calculate scattered wavefields and the pure-path approximation to modulate the phase of incident and scattered wavefields. This depends upon a decomposition of the aspherical structure into smooth and rough components. The uncoupled integral equations are discretized and solved in the frequency domain, and time domain results are obtained by inverse Fourier transform. Examples show the utility of the normal mode approach to synthesize the seismic wavefields resulting from interaction with a combination of rough and smooth structural heterogeneities. This approach is applied to an ~4 Hz shallow crustal wave propagation around the site of the San Andreas Fault Observatory at Depth (SAFOD). © The Author Geophysical Journal International © 2011 RAS. 2011 English 0956540X 10.1111/j.1365-246X.2011.05188.x Geophysical Journal International 187 1420-1442 U.S. Geological Survey, Menlo Park, CA 94025, United States 3 Aspherical; Coupled integral equations; Earth models; Earthquake source; Frequency domains; Full-waveforms; High frequency HF; Inverse Fourier transforms; Normal modes; San Andreas Fault; Seismic wavefields; Structural heterogeneity; Synthetic seismogram; Time domain; Wavefields, Born approximation; Seismology; Three dimensional; Wave propagation, Integral equations, Fourier transform; seismic source; seismic wave; synthetic seismogram; wave field; wave propagation; waveform analysis https://www.scopus.com/inward/record.uri?eid=2-s2.0-81555209057&doi=10.1111%2fj.1365-246X.2011.05188.x&partnerID=40&md5=26194f4901998d8b44167256b36a9cf0 cited By 2 F. Pollitz conference Kessler2011839 Project Hotspot: The Snake River Geothermal Drilling Project is an effort to determine the potential for geothermal energy development in the central Snake River Plain, Idaho. Few data regarding the lithologies or distribution of fractures in the vertical profile are available in the central Snake River Plain so drilling provides key data in the vertical profile to help determine the geothermal potential. Three slimhole boreholes are drilled at the Kimama, Kimberly, and Mountain Home sites to depths around 2000 m. Observations of the core will be compared with data in the complete suites of borehole geophysical logs acquired in the holes. The direct observation of lithology and fractures will be used as a constraint on geophysical data to confirm interpretations of mechanical and flow properties of the rocks. Final analysis will then describe the implications for fluid flow. Thin section and permeability test results will be used to evaluate the changes in potential fracture flow characteristics with depth. This effort will provide direct observation of samples at depth and will provide an example of a workflow to connect rock core properties, wireline log responses, and flow properties. Wireline logs can help us understand basic rock properties and the relationships between fracture distribution and rock type. Critical to the development of geothermal systems is the porosity and the potential for fluid flow in the subsurface. The volcanic nature of the formations means there is little primary permeability to contribute to fluid flow. Fractures are the primary mode of fluid transport so the analysis of fractures and the level of saturation in fracture zones are necessary to evaluate the geothermal potential. Preliminary analyses of the core show that fractures exhibit a series of alteration phases, including amygduloidal fine-grained calcite. Despite the nearly zero porosity of the matrix in the rocks, mineralizing fluids appear to form connected pathways in the rock. The borehole geophysical data show where fracture zones exist and whether the porosity produced by the fractures is sufficient for geothermal development. 2011 English 9781618394828 01935933 Transactions - Geothermal Resources Council 35 1 839-842 Department of Geology, Utah State University, Logan, UT, United States Alteration phasis; Energy development; Flow properties; Fluid transport; Fracture characterization; Fracture distributions; Fracture flow; Fracture zone; Geophysical data; Geophysical logs; Geothermal; Geothermal development; Geothermal drilling; Geothermal potential; Geothermal systems; Hot spot; Log response; Mineralizing fluids; Permeability test; Preliminary analysis; Rock core; Rock properties; Rock types; Slimhole; Snake River; Snake river plains; Thin section; Vertical profile; Wireline logs, Boreholes; Boring; Carbonate minerals; Flow of fluids; Geothermal fields; Geothermal prospecting; Geothermal wells; Lithology; Mechanical permeability; Mechanical properties; Porosity; Rivers; Rocks; Transport properties; Well logging, Fracture https://www.scopus.com/inward/record.uri?eid=2-s2.0-84860857085&partnerID=40&md5=2c0f44d3076e52d374f5ec538834ba6e cited By 3 J.A. Kessler J.P. Evans article Heinonen2011105 The Outokumpu area, located in eastern Finland, is well known for its Precambrian Cu-Zn-Co-Ni-Ag-Au sulphide deposits hosted by ophiolite-derived altered ultramafic rocks. In 2004-2005, a 2.5 km deep research borehole was drilled on the south-east side of the main ore belt. The ophiolite-related Outokumpu-assemblage rocks were penetrated at depths of 1.3-1.5 km. The other main lithologies observed in the Outokumpu Deep Drill Hole were mica schist with biotite-gneiss layers (upper 2 km) underlain by pegmatitic granite. In May 2006, high resolution reflection seismic data with 4 m receiver spacing were acquired at the drilling site along two crooked lines to further refine the geological model of the area. The Outokumpu Deep Drilling Project provided an excellent opportunity to correlate high resolution seismic data with drilling results. The main emphasis in the processing of the reflection seismic data was put on static corrections. Substantial topographic variation and a significant velocity contrast between the glacially deposited overburden and the bedrock caused severe travel time variations in the near surface. Results achieved using static corrections carried out with the standard refraction method and using a tomographic approach were compared. Sonic velocity and density logs were used to calculate acoustic impedances and a synthetic seismogram, and theoretical calculations were compared with reflectivity observed in the seismic section. The results indicate that the host rocks of the Outokumpu type deposits are bright reflector packages that can be observed with reflection seismic techniques. The pegmatitic granite shows only weak reflection contrast with the mica schist, but it can be delineated as homogeneous, transparent domains, whereas the mica schist is internally more heterogeneous. A fracture zone at the depth of 967 m can be observed as a sharp sub-horizontal reflector. Article 2011 English 978-952217152-8 07828535 Special Paper of the Geological Survey of Finland 2011 Kukkonen I.T. 105 – 118 51 Finland; Ita Suomen; Outokumpu; borehole; data processing; deep drilling; granite; host rock; lithology; metamorphic rock; ore deposit; pegmatite; seismic data; seismic reflection; seismogram; well logging https://www.scopus.com/inward/record.uri?eid=2-s2.0-80051865405&partnerID=40&md5=801e0d4202718f04cf8833dde9ca17ce Cited by: 17 Suvi Heinonen Ilmo T. Kukkonen Pekka J. Heikkinen Douglas R. Schmitt article Kagan2011 2011 English 21699313 Journal of Geophysical Research: Solid Earth 116 Blackwell Publishing Ltd 11 https://www.scopus.com/inward/record.uri?eid=2-s2.0-82155195575&partnerID=40&md5=06d29fdf4f3da50c51482b853e49e2fb cited By 6 E. Kagan M. Stein A. Agnon F. Neumann article Byun201159 Q-factor (or Q) that quantifies the attenuation, the intrinsic property of the material, is a very important required factor in extracting useful subsurface material properties such as lithological information, porosity, permeability, viscosity, and the degree of the saturation from the seismic data. When seismic energy propagates through the gas hydrate-bearing zone and a free gas layer below it, the considerable attenuation occurs and affects the amplitude and wavelet shape of recorded seismic data. Thus Q- factor extracted from seismic data can be used to locate the gas hydrate bearing zone and estimate its reserves. The spectral-ratio method has been widely used in computing the frequency-independent Q's from the zero-offset VSP data because of its ease and fastness. We developed a module of the spectral ratio method, and applied it to the synthetic zero-offset VSP data set and field zero-offset VSP data set. The field data were acquired at Mallik 3L-38 gas hydrate research well in Canada. The Q-factors calculated from the synthetic zero-offset VSP data using the spectral ratio method approached closer to the true values for the medium with low Q-factor than high Q-factor. The changes in the Q-factors extracted from the Mallik zero-offset data using the spectral ratio method agreed well with the boundaries of the layers, including gas hydrate zone, depicted in a reflection image. © 2011 Taylor & Francis Group, LLC. 2011 English 12269328 10.1080/12269328.2011.10541331 Geosystem Engineering 14 59-64 Department of Natural Resources and Geoenvironmental Engineering, Hanyang University, Seoul, South Korea; Petroleum and Marine Research Division, Korea Institute of Geoscience and Mineral Resources, Daejeon, South Korea 2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84883445158&doi=10.1080%2f12269328.2011.10541331&partnerID=40&md5=1f23a6329b239392bc3aa25e4ec33ebb cited By 1 J. Byun D.-G. Yoo H.-Y. Lee article Holdsworth2011132 The drilling of a deep borehole across the actively creeping Parkfield segment of the San Andreas Fault Zone (SAFZ), California, and collection of core materials permit direct geological study of fault zone processes at 2-3 km depth. The three drill cores sample both host and fault rocks and pass through two currently active, narrow (1-2 m wide) shear zones enclosed within a broader (ca. 240 m wide) region of inactive foliated gouges. The host rocks preserve primary sedimentary features and are cut by numerous minor faults and small, mainly calcite-filled veins. The development of Fe-enriched smectitic phyllosilicate networks following cataclasis is prevalent in the presently inactive foliated gouges of the main fault zone and in minor faults cutting clay-rich host rocks. Calcite, anhydrite and minor smectitic phyllosilicate veins are interpreted to have formed due to local fluid overpressuring events prior to, synchronous with and after local gouge development. By contrast, the active shear zone gouges lack mineral veins (except as clasts) and contain numerous clasts of serpentinite. Markedly Mg-rich smectitic phyllosilicates are the dominant mineral phases here, suggesting that the fault zone fluids have interacted with the entrained serpentinites. We propose that weakening of the SAFZ down to depths of at least 3 km can be attributed to the pervasive development of interconnected networks of low friction smectitic phyllosilicates and to the operation of stress-induced solution-precipitation creep mechanisms. © 2010 Elsevier Ltd. 2011 English 01918141 10.1016/j.jsg.2010.11.010 Journal of Structural Geology 33 132-144 Reactivation Research Group, Department of Earth Sciences, University of Durham, Durham DH1 3LE, United Kingdom; HPT Laboratory, Utrecht University, Utrecht, Netherlands; Durham GJ Russell Microscopy Facility, Durham University, Durham DH1 3LE, United Kingdom 2 Fault zone; Phyllosilicate; SAFOD; San Andreas Fault; Smectites, Calcite; Carbonate minerals; Clay minerals; Core drilling; Core samples; Fluids; Sedimentary rocks; Silicate minerals, Structural geology, active fault; core analysis; creep; deformation mechanism; drilling; fault zone; foliation; overpressure; phyllosilicate; San Andreas Fault; shear zone; smectite; stress change; stress field, California; Parkfield; San Andreas; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-78751574107&doi=10.1016%2fj.jsg.2010.11.010&partnerID=40&md5=96b51568d32c5906ce6a6ee7d1fc8a68 cited By 142 R.E. Holdsworth E.W.E. Diggelen C.J. Spiers J.H.P. Bresser R.J. Walker L. Bowen article Reinthal2011126 Numerous biological and chemical paleorecords have been used to infer paleoclimate, lake level fluctuation and faunal composition from the drill cores obtained from Lake Malawi, Africa. However, fish fossils have never been used to examine changes in African Great Lake vertebrate aquatic communities nor as indicators of changing paleolimnological conditions. Here we present results of analyses of a Lake Malawi core dating back ~144ka that describe and quantify the composition and abundance of fish fossils and report on stable carbon isotopic data (δ13C) from fish scale, bone and tooth fossils. We compared the fossil δ13C values to δ13C values from extant fish communities to determine whether carbon isotope ratios can be used as indicators of inshore versus offshore pelagic fish assemblages. Fossil buccal teeth, pharyngeal teeth and mills, vertebra and scales from the fish families Cichlidae and Cyprinidae occur in variable abundance throughout the core. Carbon isotopic ratios from numerous fish fossils throughout the core range between -7.2 and -27.5%, similar to those found in contemporary Lake Malawi benthic and pelagic fish faunas. These results are the first paleo-record of fish fossils from a Lake Malawi sediment core and the first reported δ13C values from Lake Malawi fish fossils. This approach provides a new methodology and framework for interpreting pelagic versus inshore fish faunas, lake level fluctuations and the evolution of the Lake Malawi fish assemblages. © 2010 Elsevier B.V. 2011 English 00310182 10.1016/j.palaeo.2010.01.004 Palaeogeography, Palaeoclimatology, Palaeoecology 303 126-132 Department of Ecology and Evolutionary Biology, The University of Arizona, Tucson, AZ 85721, United States; Department of Geosciences, University of Arizona, Tucson, AZ 85721, United States 1-4 carbon isotope; cichlid; climate change; cyprinid; fossil assemblage; fossil record; ichthyofauna; lake level; paleoclimate; paleolimnology; pelagic fish; sediment core; stable isotope, Africa; East African Lakes; Lake Malawi, Cichlidae; Cyprinidae; Cypriniformes; Vertebrata https://www.scopus.com/inward/record.uri?eid=2-s2.0-79953164040&doi=10.1016%2fj.palaeo.2010.01.004&partnerID=40&md5=3b12c24cf252da3285db14e1be95bab7 cited By 17 P.N. Reinthal A.S. Cohen D.L. Dettman article Piribauer2011169 Fluid inclusions in quartz veins in the Outokumpu Deep Drill Core are characterised by high salinities and high homogenisation temperatures in excess of 330 °C. In addition to an aqueous phase, fluid inclusions also contain gaseous phases such as CO2 and CH4. The cation ratios of the dissolved salts are higher than seawater, with Li/Na ratios indicating the influence of magmatic water in deeper parts of the drill hole. Stable isotope (δD, δ18O) signatures point to a metamorphic origin of the palaeofluids. Deep groundwaters in the Outokumpu crystalline basement deviate significantly from fluid inclusions in their stable isotope ratios, which plot to the right of the global meteoric water line in a δD, δ18O diagram. This suggests that they may have formed as a mixture of meteoric and saline waters. In addition, Cl/Br and Na/Br ratios point to chemical exchange with the host rocks. Many models have been proposed to account for the enhanced salinity of deep groundwaters and the shift in the stable isotopes, but our data indicate that the saline fluids are primarily derived through water-rock interaction. The role of fluid inclusions as important contributors to the saline fluids is not supported. Article 2011 English 978-952217152-8 07828535 Special Paper of the Geological Survey of Finland 2011 Kukkonen I.T. 169 – 180 51 Finland; Ita Suomen; Outokumpu; fluid inclusion; groundwater; host rock; isotopic ratio; meteoric water; oxygen isotope; quartz vein; salinity; stable isotope; water-rock interaction https://www.scopus.com/inward/record.uri?eid=2-s2.0-80051878476&partnerID=40&md5=d8edb04984bcbe0c06590a774b3ef3f0 Cited by: 6 Christoph J. Piribauer Sven Sindern F. Michael Meyer Torsten W. Vennemann Walter Prochaska article Mittempergher2011 The San Andreas Fault Observatory at Depth (SAFOD) in Parkfield, central California, has been drilled through a fault segment that is actively deforming through creep and microearthquakes. Creeping is accommodated in two fault strands, the Southwest and Central Deforming Zones, embedded within a damaged zone of deformed shale and siltstone. During drilling, no pressurized fluids have been encountered, even though the fault zone acts as a permeability barrier to fluid circulation between the North American and Pacific plates. Microstructural analysis of sheared shales associated with calcite and anhydrite-bearing veins found in SAFOD cores collected at 1.5m from the Southwest Deforming Zone, suggests that transient increases of pore fluid pressure have occurred during the fault activity, causing mode I fracturing of the rocks. Such build-ups in fluid pressure may be related to permeability reduction during fault creep and pressure-solution processes, resulting in localized failure of small fault zone patches and providing a potential mechanism for the initiation of some of the microearthquakes registered in the SAFOD site. Copyright © 2011 by the American Geophysical Union. 2011 English 00948276 10.1029/2010GL046129 Geophysical Research Letters 38 Blackwell Publishing Ltd Dipartimento di Geoscienze, Università di Padova, Via G. Gradenigo 6, I-35131 Padua, Italy; LGIT, Université Joseph Fourier-Grenoble i, BP 53, F-38041 Grenoble Cedex 9, France; Istituto Nazionale di Geofisica e Vulcanologia, Via di Vigna Murata, 605, I-00143 Roma, Italy; Department of Geography and Geosciences, University of Louisville, 212 Lutz Hall, Louisville, KY 40292, United States 3 Carbonate minerals; Creep; Drilling fluids; Structural geology, California; Damaged zones; Deforming zone; Fault activity; Fault creep; Fault strands; Fault zone; Fluid circulation; Fluid pressures; Localized failure; Micro-earthquakes; Microstructural analysis; North American; Pacific plates; Permeability barriers; Permeability reduction; Pore fluid pressure; Potential mechanism; San Andreas Fault; Siltstones; Solution process, Shale, creep; fault zone; fluid pressure; microearthquake; microstructure; North American plate; Pacific plate; permeability; San Andreas Fault; shale; siltstone, California; Parkfield; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-79551584054&doi=10.1029%2f2010GL046129&partnerID=40&md5=cb7ea09ae4b9e1f813e8dbafd0e29162 cited By 29 S. Mittempergher G. Di Toro J.P. Gratier J. Hadizadeh S.A.F. Smith R. Spiess article Lippmann-Pipke20112134 An on-site gas monitoring study has been conducted in the framework of an earthquake laboratory (The International NELSAM-DAFGAS projects) at the TauTona gold mine, South Africa. Five boreholes up to 60m long were drilled at 3.54km depth into the highly fractured Pretorius Fault Zone and instruments for chemical and seismic monitoring installed therein. Over the span of 4years sensitive gas monitoring devices were continuously improved to enable the direct observation of geogas concentration variations in the DAFGAS borehole. The major gas concentrations are constant and air-like with about 78% N2, 21% O2, 1% Ar. The geogas components CO2, CH4, He and H2 show the most interesting trends and variations on the minute-by-minute basis and significantly correlate with seismic data, while the 222Rn activity remains constant. Time series and cross correlation analysis allow the identification of different gas components (geogas and tunnel air) and the identification of two processes influencing the borehole gas composition: (1) pumping-induced tunnel air breakthrough through networks of initially water-saturated fault fractures; and (2) seismicity induced permeability enhancement of fault fractures to above ∼5×10-10m2. The current set-up of the gas monitoring system is sensitive enough to quantify the resulting geogas transport during periods of intense blasting activities (including recorded blasts with seismic moment ≤1×109Nm, located within 1000m of the cubby) and, it is suggested, also during induced earthquakes, a final goal of the project. © 2011 Elsevier Ltd. 2011 English 08832927 10.1016/j.apgeochem.2011.07.011 Applied Geochemistry 26 2134-2146 Institute of Radiochemistry, Helmholtz-Zentrum Dresden-Rossendorf - Research Site Leipzig, Permoserstr. 15, 04318 Leipzig, Germany; Helmholtz-Zentrum Potsdam, Deutsches GeoForschungsZentrum, Telegrafenberg, 14473 Potsdam, Germany; Department of Earth Sciences, University of New Hampshire, 56 College Rd., Durham, NH 03824, United States; Department of Microbial, Biochemical and Food Biotechnology, University of the Free State, Bloemfontein 9300, South Africa; Rock Engineering, TauTona Gold Mine, AngloGold Ashanti, Carletonville, South Africa; Integrated Ocean Drilling Program, Texas AandM University, 1000 Discovery Drive, College Station, TX 77845, United States; School of Geology and Geophysics, Oklahoma University, 100 East Boyd Street Suite 810, Norman, OK 73019, United States 12 Concentration variation; Cross-correlation analysis; Fault zone; Gas component; Gas compositions; Gas concentration; Gas monitoring; Gas monitoring systems; Hard rocks; Permeability enhancement; Seismic datas; Seismic moment; Seismic monitoring; South Africa, Boreholes; Carbon dioxide; Earthquakes; Fracture; Gas detectors; Gold; Gold mines; Time series; Time series analysis, Gases, borehole; correlation; fault zone; fractured medium; gas transport; gold mine; hard rock; induced seismicity; mining industry; radon isotope; seismic data; time series, South Africa https://www.scopus.com/inward/record.uri?eid=2-s2.0-82155173449&doi=10.1016%2fj.apgeochem.2011.07.011&partnerID=40&md5=01d9c37de40a8833bb3dabdb3e2d2666 cited By 24 J. Lippmann-Pipke J. Erzinger M. Zimmer C. Kujawa M. Boettcher E.V. Heerden A. Bester H. Moller N.A. Stroncik Z. Reches article Ali2011237 4He accumulated in fluids is a well established geochemical tracer used to study crustal fluid dynamics. Direct fluid samples are not always collectable; therefore, a method to extract rare gases from matrix fluids of whole rocks by diffusion has been adapted. Helium was measured on matrix fluids extracted from sandstones and mudstones recovered during the San Andreas Fault Observatory at Depth (SAFOD) drilling in California, USA. Samples were typically collected as subcores or from drillcore fragments. Helium concentration and isotope ratios were measured 4-6 times on each sample, and indicate a bulk 4He diffusion coefficient of 3.5 ± 1.3 × 10-8 cm2 s-1 at 21°C, compared to previously published diffusion coefficients of 1.2 × 10-18 cm2 s-1 (21°C) to 3.0 × 10-15 cm2 s-1 (150°C) in the sands and clays. Correcting the diffusion coefficient of 4Hewater for matrix porosity (~3%) and tortuosity (~6-13) produces effective diffusion coefficients of 1 × 10-8 cm2s-1 (21°C) and 1 × 10-7 (120°C), effectively isolating pore fluid 4He from the 4He contained in the rock matrix. Model calculations indicate that &lt;6% of helium initially dissolved in pore fluids was lost during the sampling process. Complete and quantitative extraction of the pore fluids provide minimum in situ porosity values for sandstones 2.8 ± 0.4% (SD, n = 4) and mudstones 3.1 ± 0.8% (SD, n = 4). © 2010 Springer-Verlag. 2011 English; French; Spanish 14312174 10.1007/s10040-010-0645-6 Hydrogeology Journal 19 237-247 Lamont-Doherty Earth Observatory, 61 Route 9W, Palisades, NY 10964, United States; Department of Earth and Environmental Sciences, Columbia University, 2960 Broadway, New York, NY 10027, United States; Department of Environmental Science, Barnard College, 3009 Broadway, New York, NY 10027, United States; Department of Marine Sciences, University of Connecticut, 1080 Shennecossett Road, Groton, CT 06340, United States; Lawrence-Berkeley National Laboratory, 1 Cyclotron Road, MS70A-4418, Berkeley, CA 94720, United States; National Science Foundation, 4201 Wilson Boulevard, Arlington, VA 22230, United States 1 concentration (composition); diffusion; fluid dynamics; geoaccumulation; helium; hydrogeology; isotopic ratio; porosity; tortuosity; tracer https://www.scopus.com/inward/record.uri?eid=2-s2.0-78751521016&doi=10.1007%2fs10040-010-0645-6&partnerID=40&md5=2e149799966c4357e85d8a5c3e0e0664 cited By 4 S. Ali M. Stute T. Torgersen G. Winckler B.M. Kennedy inproceedings hedin_high_2011 The Caledonides were once a mountain range of Himalayan dimensions, but are today eroded down to mid crustal levels. In the Scandes, major allochthons are inferred to have been transported hundreds of kilometers from subduction zones along the margin of the Paleozoic Baltica continent onto the Baltoscandian platform. A proposal has been sent to the International Continental Scientific Drilling Program (ICDP) to drill through the long transported allochthons into the Baltica basement. During the summer of 2010 a seismic reflection survey was acquired in the Åre region of western Sweden as a preparation for the COSC deep drilling project. The COSC project will study the fossilized orogenic processes that governed the formation of the Scandinavian Caledonides and test different hypothesis related to orogenesis. The seismic section correlates well with older surveys made in the area, but it also provides a much higher resolution image of the upper few kilometers of the crust. The subsurface is extremely reflective and we interpret a basal décollement, which is one of the main targets with the drilling, to be located at a depth of about 1.5 to 2 km in the eastern parts of the section. 2011 AGH University of Science and Technology

Krakow, Poland

P. Hedin C. Juhlin D. G. Gee A. Malehmir article Laj2011170 We report on new paleointensity and inclination records obtained in Hawaii from 386 samples drilled in 137 subaerial flows of the HSDP2 long basaltic core that we have combined in a composite record with the other Hawaiian results to produce a unique and accurate lava record of absolute geomagnetic field intensity and inclination at Hawaii for the last 405kyr. These data are considered together with published results from La Réunion Island, for about the same time period in order to compare them to model results. In Hawaii, when recognized excursional periods are omitted, the average VADM (VDM) value is about 8.2×(8.4)×1022Am2 and the inclination is on the average 29.8°, i.e. about 6° shallower than the expected value at this location (GAD value). In the Réunion Island, we selected published results in which both inclination and intensities values are obtained using modern methods and strict criteria. The average VADM (VDM) is 9.4±2.3 (8.7±2.3)1022Am2 and the average inclination value (when transitional data are ignored) is -44.4±2.4°, about 7° steeper than the GAD value. These results, compared with model intensities predicted by dynamo solutions that incorporate lateral variations in core-mantle boundary heat-flow derived from seismic tomography, are too high for both localities, but they decrease as the amplitude of thermal boundary anomalies increases. With strong boundary heat-flow, the model inclination anomaly at Hawaii fits with the data but at La Réunion, model inclination anomalies have the wrong sign. This comparison indicates that strong boundary heat-flow anomalies give the best fit to the data and that future improvements will be obtained by proportionally increasing both the Rayleigh number and the amplitude of heat-flow variations. © 2011 Elsevier B.V. Article 2011 English 00319201 10.1016/j.pepi.2011.05.007 Physics of the Earth and Planetary Interiors 187 170 – 187 3-4 Hawaii [United States]; United States; Calluna vulgaris; Electric generators; Seismology; Best fit; Core-mantle boundary; Expected values; Geomagnetic fields; Geomagnetic modeling; Hawaii; Heat-flow; Lateral variations; Model results; Paleointensity; Rayleigh number; Seismic tomography; Subaerial flows; Thermal boundary; Time-periods; amplitude; core-mantle boundary; geomagnetic field; heat flow; numerical model; Rayleigh number; seismic tomography; Geomagnetism https://www.scopus.com/inward/record.uri?eid=2-s2.0-80053204407&doi=10.1016%2fj.pepi.2011.05.007&partnerID=40&md5=fbc59cf74c01fd429f4b2a64b6ede82f Cited by: 13 Carlo Laj Catherine Kissel Christopher Davies David Gubbins article Wang20111047 High pore pressure in the San Andreas fault (California) was hypothesized to explain the prevailing weakness of the fault and may have major implications on the mechanics of earthquakes. However, no evidence of high pore pressure was found in the latest drilling into the San Andreas fault (SAFOD: San Andreas Fault Observatory at Depth) in central California (Zoback et al., 2010). If widely applicable, this result would impact our understanding of earthquake mechanisms on this and other active faults around the world. Here, however, I show that the available evidence from the latest SAFOD drilling may not be sufficient to reject the high pore-pressure hypothesis, and that definite knowledge of pore pressure in the fault zone may require long-term monitoring at the SAFOD site. The inference may also be useful for interpreting results from drilling projects on other active faults. © 2011 Geological Society of America. 2011 English 00917613 10.1130/G32294.1 Geology 39 1047-1050 Department of Earth and Planetary Science, University of California-Berkeley, Berkeley, CA 94720, United States 11 Active fault; California; Drilling projects; Fault zone; Long term monitoring; San Andreas Fault, Earthquakes; Strike-slip faults, Pore pressure, active fault; earthquake mechanism; fault zone; pore pressure; San Andreas Fault, California; San Andreas; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-84863120666&doi=10.1130%2fG32294.1&partnerID=40&md5=440bf76f83593f396fe09eada1b3d784 cited By 10 C.-Y. Wang article Behrens201186 Erratum 2011 English 00092541 10.1016/j.chemgeo.2010.02.008 Chemical Geology 288 86 1-2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-80051671584&doi=10.1016%2fj.chemgeo.2010.02.008&partnerID=40&md5=b134bbe0e6327fe66ff22c7b4e307c1c Cited by: 0; All Open Access, Bronze Open Access Harald Behrens article Kukkonen20119 Detailed geothermal studies of deep drill holes provide insights to heat transfer processes in the crust, and allow separation of different factors involved, such as palaeoclimatic and structural conductive effects as well as advective fluid flow effects. We present high resolution geothermal results of the 2516m deep Outokumpu Deep Drill Hole in eastern Finland drilled in 2004-2005 into a Palaeoproterozoic formation with metasedimentary rocks, ophiolite-derived altered ultramafic rocks and pegmatitic granite. The down-hole temperatures have been logged five times after end of drilling and extend to day 948 after drilling. The hole is completely cored (79% core coverage) and thermal conductivity measurements were done at 1m intervals. The geothermal results on temperature gradient, thermal conductivity and heat flow density yield an exceptionally detailed data set and indicate a significant vertical variation in gradient and heat flow density. Heat flow density increases from about 28 - 32mWm-2 in the uppermost 1000m to 40-45mWm-2 at depths exceeding 2000m. The estimated undisturbed surface heat flow value is 42mWm-2. We present results on forward and inverse transient conductive models which suggest that the vertical variation in heat flow can mostly be attributed to a palaeoclimatic effect due to ground surface temperature (GST) variations during the last 100,000years. The modeling suggests that the average GST was about -3 to -4°C during the Weichselian glaciation. Holocene GST values are within ±2° from the present average GST in Outokumpu (5°C). The topographic hydraulic heads and hydraulic conductivity of crystalline rocks are low which suggests that advective heat transfer in the formation is not significant. The slow replacement of fresh flushing water by saline formation fluids is observed in the hole, but it does not generate significant thermal disturbances in the logs. On the other hand, free sluggish thermal convection is present in the large diameter (22cm) borehole, and temperature variations in the range of few mK to 0.01K occur over times of minutes to tens of minutes. Theory suggests that convection cells are about as tall as the drill hole diameter, and thus the free convection is expected to generate only local thermal 'noise' not affecting the general geothermal results. © 2011 Elsevier B.V. Article 2011 English 00319201 10.1016/j.pepi.2011.06.002 Physics of the Earth and Planetary Interiors 188 9 – 25 1-2 Baltic Shield; Finland; Calluna vulgaris; Boreholes; Climatology; Crystalline rocks; Flow of fluids; Glacial geology; Heat transfer; Hydraulics; Rock drills; Saline water; Thermal conductivity; Thermal logging; Conductive effects; Conductive model; Convection cell; Data sets; Drill hole; Eastern Finland; Fennoscandian Shields; Finland; Fluid flow effect; Geothermal gradients; Ground surface temperature; Heat flow density; Heat flows; Heat transfer process; High resolution; Holocenes; Hydraulic heads; Inverse transient; Large diameter; Metasedimentary rocks; Paleoclimatology; Saline formation; Surface heat flow; Temperature gradient; Temperature variation; Thermal conductivity measurements; Thermal convections; Thermal disturbance; Ultramafic rocks; Vertical variation; drilling; geothermal gradient; granite; heat flow; heat transfer; hydraulic conductivity; hydraulic head; paleoclimate; Proterozoic; thermal conductivity; thermal convection; ultramafic rock; Geothermal energy https://www.scopus.com/inward/record.uri?eid=2-s2.0-80053316188&doi=10.1016%2fj.pepi.2011.06.002&partnerID=40&md5=83142dafe7f07718ebf3116dd0346bb7 Cited by: 39 Ilmo T. Kukkonen Volker Rath Liisa Kivekäs Jan Šafanda Vladimir Čermak article Kukkonen2011181 We present high resolution geothermal results from the 2516 m deep Outokumpu Deep Drill Hole in eastern Finland drilled in 2004-2005 into a Palaeoproterozoic formation with metasedimentary rocks, ophiolite-derived altered ultramafic rocks and pegmatitic granite. Detailed geothermal studies of deep drill holes provide insights into heat transfer processes in the crust, and allow the separation of different factors involved, such as palaeoclimatic and structural conductive effects as well as advective fluid flow effects. The down-hole temperatures of the Outokumpu hole have been logged five times following the end of drilling and extend to day 948 after drilling. The hole was continuously cored (79% core coverage) and thermal conductivity was measured at 1-m intervals. The temperature gradient, thermal conductivity and heat flow density results yield an exceptionally detailed geothermal data set and indicate significant vertical variation in the gradient and heat flow density. This result has important implications for correcting shallow (<1 km) heat flow data in the Fennoscandian Shield. The heat flow density was determined to increase from about 28-32 mW m-2 in the uppermost 1000 m to 40-45 mW m-2 at depths exceeding 2000 m. The estimated undisturbed surface heat flow value was 42 mWm-2. We present results based on inverse transient conductive models that suggest that the vertical variation in heat flow can mostly be attributed to a palaeoclimatic effect due to ground surface temperature (GST) variations during the last 100,000 years. The modelling suggests that the average GST was about -3...- 4 °C during the Weichselian glaciation. Holocene GST values are within ±2 degrees of the present average GST in Outokumpu (5 °C). The topographic hydraulic heads and hydraulic conductivity of crystalline rocks are low, which suggests that advective heat transfer in the formation is not significant. The slow replacement of fresh flushing water by saline formation fluids is observed in the hole, but it does not generate significant thermal disturbances in the logs. On the other hand, free sluggish thermal convection is present in the large diameter (22 cm) borehole, but it generates only local thermal 'noise' in the range of 0.001-0.01 K not affecting the general geothermal results. Article 2011 English 978-952217152-8 07828535 Special Paper of the Geological Survey of Finland 2011 Kukkonen I.T. 181 – 198 51 Baltic Shield; Finland; Ita Suomen; Outokumpu; Calluna vulgaris; borehole; crystalline rock; geothermal gradient; granite; heat flow; heat transfer; hydraulic conductivity; hydraulic head; metasedimentary rock; paleoclimate; surface temperature; temperature gradient; thermal conductivity; thermal convection; ultramafic rock https://www.scopus.com/inward/record.uri?eid=2-s2.0-80051915212&partnerID=40&md5=5b3bc4b199c1677a83b2af74165a2ae4 Cited by: 5 Ilmo T. Kukkonen Volker Rath Liisa Kivekäs Jan Šafanda Vladimir Čermak article 2010 09 en 0034-7744 10.15517/rbt.v58i2.5252 Revista de Biologia Tropical 58 scielo 871 - 895 Liseth Pérez Julia Lorenschat Rita Bugja M. Brenner Burkhard Scharf Antje Schwalb article Schippers2010170 Sediments in the Indian Ocean off the coast of the Indonesian island Sumatra were sampled at 25 stations in high resolution near the sediment surface and at three stations up to a maximum depth of 12 meter below seafloor (mbsf) for a quantitative microbial community analysis. Total cell counts were determined applying two different protocols including SYBR Green II as fluorescent staining dye. Total cell counts without detaching cells from sediment particles were 109 cells/ mL sediments at the sediment surface with little variation between all stations. They decreased to 108 cells/ mL at 0.2 to 0.4 mbsf and to 107 cells/ mL below 6 mbsf. The total cell counts after detaching cells from sediment particles were up to one order of magnitude lower above 6 mbsf and showed similar values below. This difference for the two protocols can be explained by a loss of cells during the detachment procedure and/or counting of unspecific signals without detaching cells from sediment particles. Particular phylogenetic and physiological prokaryotic groups were quantified by quantitative, real-time PCR (Q-PCR) targeting 16S rRNA and functional genes. Archaea and Bacteria were found overall in similar 16S rRNA gene copy numbers in the range of the total cell counts at all sediment depths, thus, neither Archaea nor Bacteria could be considered as dominant. The eukaryotic 18S rRNA gene occurred in two orders of magnitude lower numbers than prokaryotic 16S rRNA genes. Fe(III)- and Mn(IV)-reducing bacteria (16S rRNA gene of Geobacteraceae) and sulfate-reducing bacteria (functional gene dsrA) were detected in variable (up to 108 gene copies/ mL sediment) but in always significantly lower numbers than total Bacteria. The proportion of sulfate reducers on the prokaryotic community was between 0.2 and 19%. Calculated aereal sulfate reduction rates were overall low with values between 0.002 and 0.027 mmol m-2a-1, resulting in sulfate reduction rates per cell of 0.0007 and 0.81 fmol cell-1 a-1, similar to published data for other deeply buried marine sediments. Methanogenesis did not seem to play a big role since methane was detected only below 6.5 mbsf, and the functional gene of methanogens and anaerobic methanotrophs mcrA could not be detected in any sample. Article 2010 English 15210529 10.1080/01490450903456798 Geomicrobiology Journal 27 170 – 182 2 Greater Sunda Islands; Indian Ocean; Sumatra; Sunda Isles; Archaea; Bacteria (microorganisms); Eukaryota; Geobacteraceae; Prokaryota; bacterium; marine sediment; methanogenesis; microbial community; polymerase chain reaction; prokaryote; quantitative analysis; seafloor https://www.scopus.com/inward/record.uri?eid=2-s2.0-77949563943&doi=10.1080%2f01490450903456798&partnerID=40&md5=5ee995b15574b48bf60dfa22e93798e5 Cited by: 24 Axel Schippers Gerrit Köweker Carmen Höft Barbara M.A. Teichert article Görgün2010170 We investigate aftershock focal mechanisms along the eastern part of the Izmit Mw = 7.4 August 17, 1999 rupture zone during the time period August 22, 1999-October 17, 1999. Two spatial clusters of aftershock activity are analyzed representing the Karadere Fault (KF) and the Düzce Area (DA). Based on an aftershock hypocenter catalogue restricted to events with horizontal and vertical errors &lt; 2 km, we determine fault plane solutions for 221 events. The high number of focal mechanisms at the eastern Izmit rupture zone could be determined only due to the low magnitude-detection threshold of the seismic network and allows to resolve the local deformation pattern with unprecedented precision. Focal mechanisms along the Karadere Fault allow us to identify dominantly dextral strike-slip mechanisms with normal faulting components on NE-SW trending fault planes. Focal mechanisms in the Düzce Area predominantly exhibit NE-SW extensional normal faulting but also a substantial part of strike-slip faulting. Further subdivision of the data set slightly decreases for the misfit for deeper (z &gt; 10 km) events. North and east of the easternmost end of the Karadere Fault we observe a high variance in stress field orientation correlated with lower b-values. While the Karadere Fault reflects a predominant dextral strike-slip regime with normal faulting components, the Düzce Area further to the East that also hosted the forthcoming Mw = 7.2 mainshock 87 days after the Izmit earthquake can be subdivided into a dominantly NE-SW extensional normal faulting regime below the Düzce Basin (DB) and a first-order strike-slip regime along the western Düzce Fault (DF). We conclude that the Düzce Basin was set under tension by the Izmit rupture and partly released the slip deficit by extensional faulting on Karadere Fault parallel to the coseismic displacement. At the same time this area and in particular the Düzce Fault that bounds the Düzce Basin to the south reflects mostly strike-slip events representing a major asperity along the North Anatolian Fault Zone (NAFZ) before initiating the Düzce rupture 87 days after the Izmit event. © 2009 Elsevier B.V. All rights reserved. 2010 English 00401951 10.1016/j.tecto.2009.07.012 Tectonophysics 482 170-181 Helmholtz Centre Potsdam GFZ, German Research Centre for Geosciences, Telegrafenberg, 14473 Potsdam, Germany 1-4 Fault plane solutions; Izmit earthquakes; North Anatolian Fault Zone; Seismotectonics; Stress tensors, Earthquakes; Focusing; Tensors, Aircraft accidents, aftershock; earthquake catalogue; earthquake hypocenter; earthquake magnitude; earthquake rupture; extensional tectonics; fault zone; faulting; focal mechanism; seismotectonics; spatial variation; strike-slip fault; tectonic setting, Anatolia; Duzce; Izmit; Kocaeli [Turkey]; Turkey https://www.scopus.com/inward/record.uri?eid=2-s2.0-76349083599&doi=10.1016%2fj.tecto.2009.07.012&partnerID=40&md5=bca1fbb017f2edfd50d35ad5be681802 cited By 26 E. Görgün M. Bohnhoff F. Bulut G. Dresen article Reshetnikov2010 We have developed a new passive seismic imaging approach that consists of two steps. First, the hypocenter of the microseismic event is precisely located. Second, this event is treated as a "pseudo-active" seismic source and the reflections within the recorded wavefield are processed by using a directional migration algorithm in order to construct a high-resolution image of the illuminated subsurface region. In this paper we demonstrate the application of our approach to a number of microseismic events recorded by a borehole array in the San Andreas Fault Observatory at Depth main hole. Results obtained were high-resolution 3-D images of different SE-NW-oriented reflectors related to the San Andreas Fault (SAF) system in the close vicinity of the borehole. To support our approach, we compared our findings with other active and passive seismic images and analyzed the correlation with borehole lithology. We revealed a predominantly satisfactory agreement for both juxtapositions. Furthermore, the stacked image of several microearthquakes provides a spatial characterization of the complex internal structure of the SAF, with much higher resolution than can be obtained from surface seismic reflection data. Copyright 2010 by the American Geophysical Union. 2010 English 21699313 10.1029/2009JB007049 Journal of Geophysical Research: Solid Earth 115 Blackwell Publishing Ltd Institute for Geological Sciences, Freie Universitaet Berlin, Bldg. D, Malteserstrasse 74-100, D-12249 Berlin, Germany 12 algorithm; image resolution; imaging method; microearthquake; San Andreas Fault; seismic data; seismic reflection; seismic source; seismology; stacking; wave field https://www.scopus.com/inward/record.uri?eid=2-s2.0-78650949932&doi=10.1029%2f2009JB007049&partnerID=40&md5=4c6c0e251e7cebb83818ad90ee77332f cited By 49 A. Reshetnikov S. Buske S.A. Shapiro article Barton2010103 Chicxulub is the only known impact structure on Earth with a fully preserved peak ring, and it forms an important natural laboratory for the study of large impact structures and understanding of large-scale cratering on Earth and other planets. Seismic data collected in 1996 and 2005 reveal detailed images of the uppermost crater in the central basin at Chicxulub. Seismic reflection profiles show a reflective layer ∼1 km beneath the apparent crater floor, topped by upwardly concave reflectors interpreted as saucer-shaped sills. The upper part of this reflective layer is coincident with a thin high-velocity layer identified by analyzing refractions on the 6 km seismic streamer data. The high-velocity layer is almost horizontal and appears to be contained within the peak ring structure. We argue that this reflective layer is the predicted coherent melt sheet formed during impact, and it may be comparable with the unit known as the Sudbury Igneous Complex at the Sudbury impact structure. The Sudbury Igneous Complex, interpreted as a differentiated impact melt sheet, appears to have a similar scale and geometry, and an uppermost lithological sequence consisting of a high velocity layer at the top and a velocity inversion beneath. This comparison suggests that the Chicxulub impact structure also contains a coherent differentiated melt sheet. © 2010 The Geological Society of America. All rights reserved. 2010 10.1130/2010.2465(07) Special Paper of the Geological Society of America 465 103-113 Bullard Laboratories, University of Cambridge, Madingley Road, Cambridge CB3 OEZ, United Kingdom; Geological Survey of Canada, 601 Booth Street, Ottawa, ON K1A 0Y3, Canada; Department of Earth Science and Engineering, South Kensington Campus, Imperial College, London, London SW7 2AZ, United Kingdom; Institute for Geophysics, Jackson School of Geosciences, University of Texas at Austin, Austin, TX 78758, United States; Surendra-Shell International, Hague, Netherlands; Vermeesch-National Oceanography Centre, University of Southampton, European Way, Southampton SO14 3ZH, United Kingdom https://www.scopus.com/inward/record.uri?eid=2-s2.0-78650951364&doi=10.1130%2f2010.2465%2807%29&partnerID=40&md5=d917cf3dca0845007069930b52695c97 cited By 20 P.J. Barton R.A.F. Grieve J.V. Morgan A.T. Surendra P.M. Vermeesch G.L. Christeson S.P.S. Gulick M.R. Warner article youfeng2010sedimentary 2010 Acta Petrologica Sinica 26 SCIENCE PRESS 16 DONGHUANGCHENGGEN NORTH ST, BEIJING 100717, PEOPLES R CHINA 99-108 1 GAO Youfeng WANG Pujun Qu Xuejiao WANG Guodong article Albrecht20103435 Ancient Lake Ohrid is probably of early Pleistocene or Pliocene origin and amongst the few lakes in the world harbouring an outstanding degree of endemic biodiversity. Although there is a long history of evolutionary research in Lake Ohrid, particularly on molluscs, a mollusc fossil record has been missing up to date. For the first time, gastropod and bivalve fossils are reported from the basal, calcareous part of a 2.6 m long sediment succession (core Co1200) from the north-eastern part of Lake Ohrid. Electron spin resonance (ESR) dating of mollusc shells from the same stratigraphic level yielded an age of 130 ± 28 ka. Lithofacies III sediments, i.e. a stratigraphic subdivision comprising the basal succession of core Co1200 between 181.5-263 cm, appeared solid, greyish-white, and consisted almost entirely of silt-sized endogenic calcite (CaCO3>70%) and intact and broken mollusc shells. Here we compare the faunal composition of the thanatocoenosis with recent mollusc associations in Lake Ohrid. A total of 13 mollusc species (9 gastropod and 4 bivalve species) could be identified within Lithofacies III sediments. The value of sediment core fossils for reconstructing palaeoenvironmental settings was evaluated and the agreement between sediment and palaeontological proxies was tested. The study also aims at investigating major faunal changes since the Last Interglacial and searching for signs of extinction events. The combined findings of the ecological study and the sediment characteristics suggest deposition in a shallow water environment during the Last Interglacial. The fossil fauna exclusively included species also found in the present fauna, i.e. no extinction events are evident for this site since the Last Interglacial. The thanatocoenosis showed the highest similarity with recent Intermediate Layer (5-25 m water depth) mollusc assemblages. The demonstrated existence of a mollusc fossil record in Lake Ohrid sediment cores also has great significance for future deep drilling projects. It can be hoped that a more far reaching mollusc fossil record will then be obtained, enabling insight into the early evolutionary history of Lake Ohrid. © Author(s) 2010. Article 2010 English 17264189 10.5194/bg-7-3435-2010 Biogeosciences 7 3435 – 3446 11 Lake Ohrid; Bivalvia; Gastropoda; Mollusca; biostratigraphy; deep drilling; fossil record; interglacial; mollusc; paleoenvironment; paleontology; sediment core https://www.scopus.com/inward/record.uri?eid=2-s2.0-78249236524&doi=10.5194%2fbg-7-3435-2010&partnerID=40&md5=c22e0b3c5af8a8b8a61cc1e386499648 Cited by: 10; All Open Access, Gold Open Access, Green Open Access C. Albrecht H. Vogel T. Hauffe T. Wilke conference Lewis20104034 We use noise cross-correlation between stations in the San Andreas Fault Observatory at Depth (SAFOD) pilot hole to extract P and S waves from a noise source at depth and measured anisotropy of the S wave on the horizontal components. The continuous data is recorded at 7 threecomponent stations at depths from ~500-800m in the pilot hole. In late September and early October 2004 a noise source is observed propagating from underneath the stations, while in mid and late October the propagating noise signal is absent. This time is consistent with the temporary end of drilling in the SAFOD main-hole for the winter, making drilling activity the likely source of the noise. We cross-correlate between the deepest station and the other six stations in the pilot hole to get an estimate of the P and S wave portions of the Green's function on the vertical and horizontal components, respectably. The velocity of the propagating waves is largely consistent with velocity measurements taken in the borehole when taking into account the angle between the source and receivers. We observe polarization in the S wave, with a fast polarization direction of 120?130?that is 3-4% faster than the slow direction. © 2010 SEG. 2010 English 9781617389801 10.1190/1.3513700 Society of Exploration Geophysicists International Exposition and 80th Annual Meeting 2010, SEG 2010 Society of Exploration Geophysicists 4034-4040 Marine Physical Laboratory, Scripps Institution of Oceanography, United States Boreholes; Geophysical prospecting; Infill drilling; Polarization; Shear flow; Strike-slip faults, Continuous data; Cross correlations; Drilling activity; Polarization direction; Propagating waves; San Andreas fault; Seismic interferometries; Shear wave splitting, Shear waves https://www.scopus.com/inward/record.uri?eid=2-s2.0-85055489625&doi=10.1190%2f1.3513700&partnerID=40&md5=5938d5cabae85641c27c56bf4549884d cited By 0 M.A. Lewis P. Gerstoft article Giresse2010341 This study presents a synthetic approach based on the combined use of sediment and C org accumulation rates of well studied lake systems and oceanic margins. Importance of latitude is expressed by the advected flux of terrestrial sediment and, especially, of particulate organic carbon. This most important factor varies throughout the Quaternary, particularly with the intensification of fluxes during Holocene. These changes are linked to the strengthening of monsoon circulation.In various lake systems from Cameroon (Barombi Mbo, Ossa, Assom and Bambili), Gabon (Kamalete) and Congo (Kitina and Sinnda), the global sedimentation and the C org accumulation were slow during dry period and increased during wet period. This relationship is verified to the scale of the Gabon and Congo oceanic margins where the accumulation rates increase during extent of ombrophilous forest. However, the greatest fluxes of organic carbon during wet periods would be balanced by higher concentrations values during the dry period resulting in a nearly homogenous carbon accumulation. These carbon concentrations are generally explained by the input of coarse debris by abrupt floods and by a less degraded organic matter as a result of the cooling of the climate. But, according to specific morphology features or vegetation cover, some lake systems exhibit distinct trends of the sedimentary and C org accumulation rates: (1) Highest accumulation rates coincided with a forest retreat when the slope is too steep (Kamalete in Gabon and Bosumtwi in Ghana) or when river flood overrun (Nguene in Gabon) (2) Increase of the accumulation rate are registered without change of the vegetal cover and express only rainfall growth (Bambili and Assom). © 2010 Elsevier B.V. Article 2010 English 09218181 10.1016/j.gloplacha.2010.01.010 Global and Planetary Change 72 341 – 355 4 Africa; Atlantic Ocean; Gulf of Guinea; Anoxic sediments; Debris; Drought; Lakes; Sedimentology; Accumulation rates; Cameroon; Carbon accumulation; Carbon concentrations; Gulf of Guinea; Holocene; Holocenes; Nearly homogenous; Organic matter; Particulate organic carbon; Particulate organic carbon fluxes; Synthetic approach; Terrestrial sediments; Vegetal cover; Vegetation cover; Wet period; accumulation rate; carbon flux; coastal sediment; Holocene; lacustrine environment; particulate organic carbon; sediment chemistry; sedimentation; terrestrial deposit; Organic carbon https://www.scopus.com/inward/record.uri?eid=2-s2.0-77957277348&doi=10.1016%2fj.gloplacha.2010.01.010&partnerID=40&md5=2228ce4934cde97b788667e5a172e0f5 Cited by: 4 P. Giresse Makaya-Mvoubou article Zoback2010197 This year, the world has faced energetic and destructive earthquakes almost every month. In January, an M = 7.0 event rocked Haiti, killing an estimated 230,000 people. In February, an M = 8.8 earthquake and tsunami claimed over 500 lives and caused billions of dollars of damage in Chile. Fatal earthquakes also occurred in Turkey in March and in China and Mexico in April. 2010 English 00963941 10.1029/2010EO220001 Eos 91 197-199 Department of Geophysics, Stanford University, Stanford, CA, United States; U.S. Geological Survey, Menlo Park, CA, United States 22 earthquake damage; fault zone; hazard assessment; tsunami, California; Chile; China; Haiti; Mexico [North America]; San Andreas; Turkey; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-77954237125&doi=10.1029%2f2010EO220001&partnerID=40&md5=9da6a525ef8692126093a0a23ff1e901 cited By 118 M. Zoback S. Hickman W. Ellsworth article Day-Lewis2010 We analyzed measurements of the direction of maximum horizontal compressive stress as a function of depth in two scientific research wells near the San Andreas Fault in central and southern California. We found that the stress orientations exhibit scale-invariant fluctuations over intervals from tens of cm to several km. Similarity between the scaling of the stress orientation fluctuations and the scaling of earthquake frequency with fault size suggests that these fluctuations are controlled by stress perturbations caused by slip on faults of various sizes in the critically-stressed crust adjacent to the fault. The apparent difference in stress scaling parameters between the two studies wells seem to correspond to differences in the earthquake magnitude-frequency statistics for the creeping versus locked sections of the fault along which these two wells are located. This suggests that stress heterogeneity adjacent to active faults like the San Andreas may reflect variations in stresses and loading conditions along the fault. © 2010 by the American Geophysical Union. 2010 English 00948276 10.1029/2010GL045025 Geophysical Research Letters 37 Blackwell Publishing Ltd Department of Geophysics, Stanford University, Mitchell Building, Stanford, CA 95305-2214, United States; U.S. Geological Survey, MS 977, 345 Middlefield Rd., Menlo Park, CA 94025, United States 24 Compressive stress; Earthquakes; Horizontal wells; Wells, Active fault; Earthquake frequency; Earthquake magnitudes; Loading condition; San Andreas Fault; Scale-invariant; Scaling parameter; Scientific researches; Southern California; Stress orientations; Stress perturbations, Stress analysis, active fault; compression; creep; earthquake magnitude; earthquake recurrence; fault zone; seismicity, California; San Andreas; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-78650496752&doi=10.1029%2f2010GL045025&partnerID=40&md5=388b1e76a33a9242855883e583aaab12 cited By 28 A. Day-Lewis M. Zoback S. Hickman article Collett20101151 It is generally accepted that the amount of gas in the world's gas hydrate accumulations exceeds the volume of known conventional gas resources. Researchers have long speculated that gas hydrates could eventually be a commercial producible energy resource yet technical and economic hurdles have historically made gas hydrate development a distant goal rather than a near-term possibility. This view began to change in recent years with the realization that this unconventional resource could possibly be developed with existing conventional oil and gas production technology. The most significant development has been gas hydrate production testing conducted at the Mallik site in Canada's Mackenzie Delta. The Mallik Gas Hydrate Production Research Well Program has yielded the first modern, fully integrated field study and production test of a natural gas hydrate accumulation. More recently, BP Exploration (Alaska) Inc. with the US Department of Energy and the US Geological Survey have successfully cored, logged and tested a gas hydrate accumulation on the North Slope of Alaska known as the Mount Elbert Prospect. The Mallik project along with the Mount Elbert effort has for the first time allowed the rational assessment of the production response of a gas hydrate accumulation. In addition to the gas hydrate production tests in Canada and the USA, marine gas hydrate research drilling, coring and logging expeditions launched by the national gas hydrate programmes in Japan, India, China and South Korea have also contributed significantly to our understanding of how gas hydrates occur in nature and have provided a much deeper appreciation of the geological controls on the occurrence of gas hydrates. With an increasing number of highly successful gas hydrate field studies, significant progress has been made in addressing some of the key issues on the formation, occurrence and stability of gas hydrates in nature. © Petroleum Geology Conferences Ltd. Published by the Geological Society, London. 2010 English 20479921 10.1144/0071151 Petroleum Geology Conference Proceedings 7 1151-1154 US Geological Survey, Denver Federal Center, MS-939, Box 25046, Denver, CO 80225, United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-80052533658&doi=10.1144%2f0071151&partnerID=40&md5=53febe98c1a1e1a51107f2797aefc727 cited By 3 T.S. Collett article NoAuthor2010299 2010 English 00401951 10.1016/j.tecto.2010.06.013 Tectonophysics 492 299-301 1-4 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84755161274&doi=10.1016%2fj.tecto.2010.06.013&partnerID=40&md5=7d2e41223de04ed884c3af242bf9a1f4 cited By 1 article Jin2010551 Two short sediment cores were recovered from sub-basins of Lake Qinghai, China and were analyzed for concentrations of Pb and 16 other elements to determine historic, regional atmospheric Pb deposition on the Tibetan Plateau. Core chronologies, dating back to the eighteenth century, were established using activities of 210Pb and 137Cs. The 17 elements were divided into three principal components. Variations in concentrations of PC1 elements (Al, Cr, Cu, Fe, K, Mn, Ni, and Ti) demonstrate different patterns between the two cores, and are attributed to different sediment sources in the two subbasins. PC2 elements (Ba, Ca, Na, and Sr) may be associated with the degree of catchment weathering and/or water chemistry. Four elements (Pb, Zn, P, and Co) are related to both PC1 and PC2, and reflect a mixture of natural and anthropogenic sources. The PC3 element is Mg in the north sub-basin, and is perhaps related to aragonite precipitation and/or increased farming. Elevated Pb concentrations in uppermost sediments of both cores signify a recent regional/global increase in anthropogenic Pb release into the environment. After subtracting lithogenic Pb, derived from rock weathering and/or dust and normalized to the background immobile element Ti, results suggest that excess, anthropogenic Pb is transferred to the lake and its sediments predominantly via the atmosphere. This anthropogenic atmospheric Pb is comparable in magnitude and displays similar variation patterns in the two cores, reflecting regional atmospheric deposition and local erosion. The average anthropogenic Pb deposition rate in Lake Qinghai since the 1960s has been ~12.2 ± 3.5 mg/ m2/a, comparable with atmospheric Pb fluxes reported for sites elsewhere in the northern hemisphere. © Springer Science+Business Media B.V. 2009. Article 2010 English 09212728 10.1007/s10933-009-9351-6 Journal of Paleolimnology 43 551 – 563 3 China; Qinghai; Qinghai Lake; Qinghai-Xizang Plateau; anthropogenic source; aragonite; atmospheric deposition; catchment; cesium isotope; chronology; concentration (composition); dust; eighteenth century; heavy metal; lacustrine deposit; lead isotope; magnitude; Northern Hemisphere; precipitation (chemistry); principal component analysis; sediment core; water chemistry; weathering https://www.scopus.com/inward/record.uri?eid=2-s2.0-77957019048&doi=10.1007%2fs10933-009-9351-6&partnerID=40&md5=09282cf5d575b9e5cb57a15a78de5af8 Cited by: 52 Zhangdong Jin Yongming Han Li Chen article ning2010productivity 2010 Journal of Jilin University (Earth Science Edition) 40 1020-1026 5 WK Ning L Fu QL Huo article Wenk2010478 Samples of fault gouge from the San Andreas Fault drill hole (SAFOD), a shale from the North Sea sedimentary basin and schists from metamorphic rocks in the Alps have been analyzed with high energy synchrotron X-rays to determine preferred orientation of mica and clay minerals. The method relies on obtaining 2D diffraction images which are then processed with the crystallographic Rietveld method, implemented in the software MAUD, allowing for deconvolution of phases and extraction of their orientation distributions. It is possible to distinguish between detrital illite/muscovite and authigenic illite/smectite, kaolinite and chlorite, and muscovite and biotite, with strongly overlapping peaks in the diffraction pattern. The results demonstrate that phyllosilicates show large texture variations in various environments, where different mechanisms produce the rock microfabrics: fault gouge fabrics are quite weak and asymmetric with maxima for (001) in the range of 1.5-2.5 multiples of random distribution (m.r.d.). This is attributed to heterogeneous deformation with randomization, as well as dissolution-precipitation reactions. Shale fabrics have maxima ranging from 3 to 9. m.r.d. and this is due to sedimentation and compaction. The strongest fabrics were observed in metamorphic schists (10-14. m.r.d.) and developed by deformation as well as recrystallization in a stress field. In the analyzed samples, fabrics of co-existing quartz are weak. All phyllosilicate textures can be explained by orientation of (001) platelets, with no additional constraints on a-axes. © 2010 Elsevier Ltd. 2010 English 01918141 10.1016/j.jsg.2010.02.003 Journal of Structural Geology 32 478-489 Department of Earth and Planetary Science, University of California, Berkeley, CA 94720, United States 4 Authigenic; Co-existing; Different mechanisms; Diffraction images; Drill hole; Fault gouge; Heterogeneous deformation; High energy synchrotron; Large textures; Micro fabric; North Sea; Orientation distributions; Overlapping peaks; Phyllosilicate; Phyllosilicate fabrics; Precipitation reaction; Preferred orientations; Random distribution; Recrystallizations; San Andreas Fault; Schist; Sedimentary basin; Stress field, Deformation; Dissolution; Holographic interferometry; Kaolinite; Metamorphic rocks; Mica; Oxide minerals; Quartz; Rietveld method; Shale; Silicate minerals; Textures, Fabrics, authigenic mineral; chemical composition; clay mineral; deconvolution; fault gouge; metamorphic rock; phyllosilicate; preferred orientation; recrystallization; Rietveld analysis; schist; sedimentary basin; shale; stress field, Atlantic Ocean; North Sea https://www.scopus.com/inward/record.uri?eid=2-s2.0-77953139643&doi=10.1016%2fj.jsg.2010.02.003&partnerID=40&md5=93e1edbf50eb2aac70074568f8fcb680 cited By 74 H.-R. Wenk W. Kanitpanyacharoen M. Voltolini article doi:10.1080/11035891003692934 2010 10.1080/11035891003692934 GFF 132 Taylor & Francis 71-81 1 Ilmo T. Kukkonen Odleiv Olesen Maria V.S. Ask PFDP WORKING GROUP article Pérez2010490 Two ~40-cm-long sediment cores, PI-SC-1-10m and PI-SC-2-40m, were recovered at 10 and 40 m water depth, respectively, from Lago Petén Itzá, in the Department of Petén, northern Guatemala. The cores span the last ~525 years of sediment accumulation in the basin. This study explores lake level and trophic state changes that Lago Petén Itzá has experienced since European contact in the early 1500s. We inferred past environmental variability using changes in sediment geochemistry and fluctuations in relative species abundances of ostracode and chironomid fossil assemblages. Changes in concentrations of organic matter (OM), carbonate, total carbon (TC), total nitrogen (TN), C/N ratios, bromine (Br), and faunal relative abundances were used to infer changes in the trophic status of the lake. Cultural eutrophication began in the 1930s, and anthropogenic impact increased significantly after ~1970. Higher linear sedimentation rates, up to 9.1 mm yr-1, began recently. They are attributed to increases in riparian settlement, deforestation and associated land use changes, which led to accelerated soil erosion. An ostracode-based transfer function was applied to assemblages in core PI-SC-1-10m, which enabled us to identify periods when lake level fluctuated. Such historical fluctuations in lake levels were driven primarily by changes in rainfall. Past lake levels can be summarized as follows: (1) fluctuating, high lake levels from ~1550s to the 1730s and from the early 1940s to 2005, and (2) stable, lower lake levels from about 1750 to the early 1900s. Higher relative abundance of the ostracode Physocypria globula and higher rubidium (Rb) concentrations indicate higher lake levels than today. Chironomids also show sharp fluctuations along the cores that could be related to water level changes. The presence of chironomid assemblages Chironomus, Procladius, and Einfeldia from 1960-2000 AD shows high productivity levels. The Lago Petén Itzá sediment record indicates a generally arid Little Ice Age (LIA), with exceptions around 1580 and 1650 when high lake levels similar to those of the 20th century, i.e. ~5 m higher than today, indicate more humid conditions. Article 2010 Spanish 10268774 Revista Mexicana de Ciencias Geologicas 27 490 – 507 3 https://www.scopus.com/inward/record.uri?eid=2-s2.0-78649702880&partnerID=40&md5=f2bc7c0b10e6c4748b2eb0fd71bb612f Cited by: 26 Liseth Pérez Rita Bugja Julieta Massaferro Philip Steeb Robert Geldern Peter Frenzel Mark Brenner Burkhard Scharf Antje Schwalb article Prokopenko201026 Lake Baikal basin in the continental interior Asia preserved a unique continuous sedimentary archive of the late Cenozoic; large-scale regional environmental changes of the past were recorded in the composition of fossil diatom flora. Here, the Lake Baikal planktonic diatom biostratigraphy is extended over the Plio-Pleistocene transition, it includes 11 new local diatom assemblage zones (LDAZ) for the time interval 1.25-3.6. Ma. The comparison of the parallel BDP-96-1 and BDP-98 drill core records allows constructing the complete diatom biostratigraphic record at the time of the inception of the Northern Hemisphere glaciations; diatom biostratigraphic zones around Matuyama/Gauss paleomagnetic reversal are correlated with individual stages of marine oxygen isotope stratigraphy. Contrary to previous assumptions, the period 2.8-2.6. Ma in Lake Baikal record was characterized not by a prolonged minimum in diatom abundance but by a distinct maximum in the abundance of small-celled diatom taxa Tertiarius baicalensis and Stephanodiscus binderanus et var. hyalinus, which proliferated in the lake during the interval of relatively warm and humid climate.The Lake Baikal diatom biostratigraphic change at around 1.8. Ma occurs only at a species level of the genus Cyclotella. By contrast, around 2.8-2.5. Ma, spectacular appearances and extinctions occurred at a high taxonomic level of genera (including the genera of Tertiarius, Thalassiobeckia and Stepahanopsis) making the biostratigraphic changes around Matuyama/Gauss reversal more prominent. At least three distinct biostratigraphic boundaries are observed: at 2.69. Ma, 2.65. Ma and at 2.46. Ma. None of these boundaries, however, coincides with the paleomagnetic reversal at 2.58. Ma. Thus the new well-resolved Lake Baikal biostratigraphic record points to the difficulty of assigning a single 'golden spike' biostratigraphic boundary around Matuyama/Gauss paleomagnetic reversal in continental Asia. © 2009 Elsevier Ltd and INQUA. Article 2010 English 10406182 10.1016/j.quaint.2009.09.027 Quaternary International 219 26 – 36 1-2 Lake Baikal; Russian Federation; Bacillariophyta; Cyclotella; Stephanodiscus binderanus; biostratigraphy; Cenozoic; continental interior; diatom; environmental change; glaciation; magnetic reversal; Northern Hemisphere; oxygen isotope; paleomagnetism; plankton; Pliocene-Pleistocene boundary https://www.scopus.com/inward/record.uri?eid=2-s2.0-77952955213&doi=10.1016%2fj.quaint.2009.09.027&partnerID=40&md5=2cd027b3e6e6833370f3357a78211e26 Cited by: 9 Alexander A. Prokopenko Galina K. Khursevich article Bartosova20101021 The ICDP-USGS Eyreville drill cores in the Chesapeake Bay impact structure reached a total depth of 1766 m and comprise (from the bottom upwards) basement-derived schists and granites/pegmatites, impact breccias, mostly poorly lithified gravelly sand and crystalline blocks, a granitic slab, sedimentary breccias, and postimpact sediments. The gravelly sand and crystalline block section forms an approximately 26 m thick interval that includes an amphibolite block and boulders of cataclastic gneiss and suevite. Three gravelly sands (basal, middle, and upper) are distinguished within this interval. The gravelly sands are poorly sorted, clast supported, and generally massive, but crude size-sorting and subtle, discontinuous layers occur locally. Quartz and K-feldspar are the main sand-size minerals and smectite and kaolinite are the principal clay minerals. Other mineral grains occur only in accessory amounts and lithic clasts are sparse (only a few vol%). The gravelly sands are silica rich (∼80 wt% SiO2). Trends with depth include a slight decrease in SiO2 and slight increase in Fe2O3. The basal gravelly sand (below the cataclasite boulder) has a lower SiO2 content, less K-feldspar, and more mica than the higher sands, and it contains more lithic clasts and melt particles that are probably reworked from the underlying suevite. The middle gravelly sand (below the amphibolite block) is finer-grained, contains more abundant clay minerals, and displays more variable chemical compositions than upper gravelly sand (above the block). Our mineralogical and geochemical results suggest that the gravelly sands are avalanche deposits derived probably from the nonmarine Potomac Formation in the lower part of the target sediment layer, in contrast to polymict diamictons higher in the core that have been interpreted as ocean-resurge debris flows, which is in agreement with previous interpretations. The mineralogy and geochemistry of the gravelly sands are typical for a passive continental margin source. There is no discernible mixing with marine sediments (no glauconite or Paleogene marine microfossils noted) during the impact remobilization and redeposition. The unshocked amphibolite block and cataclasite boulder might have originated from the outer parts of the transient crater. © 2010 The Meteoritical Society. 2010 10.1111/j.1945-5100.2010.01077.x Meteoritics and Planetary Science 45 1021-1052 Department of Lithospheric Research, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria; Department of Geodynamics and Sedimentology, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria; U.S. Geological Survey, 926A National Center, Reston, VA 20192, United States; Department of Geosciences, University of Oslo, P.O. Box 1047, Blindern, NO-0316 Oslo, Norway; Natural History Museum, Burgring 7, A-1010 Vienna, Austria 6 https://www.scopus.com/inward/record.uri?eid=2-s2.0-77957318316&doi=10.1111%2fj.1945-5100.2010.01077.x&partnerID=40&md5=dea78112779d625894bc2c5dbdee4439 cited By 1 K. Bartosova S. Gier J.W. Horton Jr. C. Koeberl D. Mader H. Dypvik article Bartosova20101021 The ICDP-USGS Eyreville drill cores in the Chesapeake Bay impact structure reached a total depth of 1766 m and comprise (from the bottom upwards) basement-derived schists and granites/pegmatites, impact breccias, mostly poorly lithified gravelly sand and crystalline blocks, a granitic slab, sedimentary breccias, and postimpact sediments. The gravelly sand and crystalline block section forms an approximately 26 m thick interval that includes an amphibolite block and boulders of cataclastic gneiss and suevite. Three gravelly sands (basal, middle, and upper) are distinguished within this interval. The gravelly sands are poorly sorted, clast supported, and generally massive, but crude size-sorting and subtle, discontinuous layers occur locally. Quartz and K-feldspar are the main sand-size minerals and smectite and kaolinite are the principal clay minerals. Other mineral grains occur only in accessory amounts and lithic clasts are sparse (only a few vol%). The gravelly sands are silica rich (∼80 wt% SiO2). Trends with depth include a slight decrease in SiO2 and slight increase in Fe2O3. The basal gravelly sand (below the cataclasite boulder) has a lower SiO2 content, less K-feldspar, and more mica than the higher sands, and it contains more lithic clasts and melt particles that are probably reworked from the underlying suevite. The middle gravelly sand (below the amphibolite block) is finer-grained, contains more abundant clay minerals, and displays more variable chemical compositions than upper gravelly sand (above the block). Our mineralogical and geochemical results suggest that the gravelly sands are avalanche deposits derived probably from the nonmarine Potomac Formation in the lower part of the target sediment layer, in contrast to polymict diamictons higher in the core that have been interpreted as ocean-resurge debris flows, which is in agreement with previous interpretations. The mineralogy and geochemistry of the gravelly sands are typical for a passive continental margin source. There is no discernible mixing with marine sediments (no glauconite or Paleogene marine microfossils noted) during the impact remobilization and redeposition. The unshocked amphibolite block and cataclasite boulder might have originated from the outer parts of the transient crater. © 2010 The Meteoritical Society. 2010 English 10869379 10.1111/j.1945-5100.2010.01077.x Meteoritics and Planetary Science 45 1021-1052 Department of Lithospheric Research, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria; Department of Geodynamics and Sedimentology, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria; U.S. Geological Survey, 926A National Center, Reston, VA 20192, United States; Department of Geosciences, University of Oslo, P.O. Box 1047, Blindern, NO-0316 Oslo, Norway; Natural History Museum, Burgring 7, A-1010 Vienna, Austria 6 https://www.scopus.com/inward/record.uri?eid=2-s2.0-77957318316&doi=10.1111%2fj.1945-5100.2010.01077.x&partnerID=40&md5=dea78112779d625894bc2c5dbdee4439 cited By 1 K. Bartosova S. Gier J.W. Horton Jr. C. Koeberl D. Mader H. Dypvik article bohnhoff2010passive 2010 New frontiers in integrated solid earth sciences Springer 261--285 Marco Bohnhoff Georg Dresen William L Ellsworth Hisao Ito article Zhang201069 Study of the Maobei garnet peridotite and pyroxenite are significant, because these rocks were subjected to subduction-zone UHP metamorphism that is indicative of deep continental subduction. In order to better understand the origin of the Maobei peridotite and pyroxenite and the processes of continental subduction, we performed geochemical analyses on whole-rock and mineral samples. The studied samples were recovered in the main-hole of the Chinese Continental Scientific Drilling in the Sulu UHP terrane, east-central China. The garnet peridotites occur as lenses or layers in pyroxenite; they comprise garnet wehrlite and garnet dunite with minor interlayers of garnet websterite and garnet. Mini-bands, nodules or veins of eclogite and garnet clinopyroxenite ("internal") also irregularly occur in garnet wehrlite. The peridotites are composed of olivine (Fo83-84), garnet (Prp51-56), ± diopside±enstatite (En86-87)±titanoclinochumite, and have lower Mg/(Mg+Fetotal) values of 0.79-0.83 and higher Al2O3 and CaO contents in comparison with the gneiss-hosted Sulu mantle peridotites. Garnet wehrlite displays variable REE patterns, from LREE-enriched to slightly LREE depleted relative to MREE and HREE; whereas, other ultramafic rocks show roughly flat REE patterns. In general, Rb, Ba and LREE increase, and compatible element (e.g. Cr, Co and Ni) abundances decrease from peridotite, pyroxenite to "internal eclogite" and "internal Grt-clinopyroxenite". The calculated REE partition coefficients (DREE) between Cpx and Grt of the Maobei peridotite and pyroxenite decrease regularly from LREE (DCe=32-708) to HREE (DYb=0.01-0.10), which is comparable with natural mantle peridotite and eclogite crystallized at 800-1100°C. The geochemical data and occurrence of these rocks suggest that the protoliths of the Maobei peridotites are cumulates derived by differentiation of basaltic magma at the lower continental crust. Thus, the "Internal eclogite and Grt-clinopyroxenite" result from post-cumulus crystallization of the trapped melt. Ti-clinohumite orthopyroxenite may have formed by reaction between peridotitic olivine and indigenous melt or country rock-derived ("exotic") TiO2-bearing fluids at high-P condition during continental subduction to mantle depths. The peak P-T estimates of 795-840°C and 5.3-6.8GPa of the Maobei peridotites and the available petrological data of country rocks indicate that the continental crust was subducted to a depth of ~200km. © 2010 Elsevier B.V. Article 2010 English 00092541 10.1016/j.chemgeo.2010.05.021 Chemical Geology 276 69 – 87 1-2 China; Jiangsu; Maobei; Analytical geochemistry; Barium; Cerium; Chromium; Garnets; Geochronology; Levees; Metamorphic rocks; Minerals; Olivine; Petrology; Rocks; Rubidium; Ytterbium; Continental subduction; Differentiation of basic magma; Scientific drilling; Sulu garnet peridotite; UHP metamorphism; chemical analysis; Chinese Continental Scientific Drilling Project; continental crust; country rock; eclogite; garnet; P-T conditions; peridotite; petrology; pyroxenite; rare earth element; tectonic evolution; ultrahigh pressure metamorphism; ultramafic rock; wehrlite; Silicate minerals https://www.scopus.com/inward/record.uri?eid=2-s2.0-77955314145&doi=10.1016%2fj.chemgeo.2010.05.021&partnerID=40&md5=745c35948b46b49bdfbfd789d5b3c442 Cited by: 21; All Open Access, Green Open Access R.Y. Zhang B.-M. Jahn J.G. Liou J.S. Yang H.-Y. Chiu S.-L. Chung T.-F. Li C.-H. Lo article Blum20101879 We present observations from a vertical, optical fiber interferometric strainmeter in the San Andreas Fault Observatory at Depth borehole near Parkfield, California. The sensor detects both teleseismic earthquakes and local events, along with coseismic strain steps consistent with theoretical dislocation models. For tele-seismic events, we investigate the possibility of determining local Rayleigh-wave phase velocities beneath the borehole by comparing the ratio of vertical ground acceleration from a nearby seismometer to vertical strain. While similar studies have used horizontal components and rotations, this is the first such attempt utilizing vertical measurements. We show that at periods from around 16-40 seconds, we can recover general dispersion characteristics that are within a few percent of models of realistic local structure. 2010 English 00371106 10.1785/0120090333 Bulletin of the Seismological Society of America 100 1879-1891 Scripps Institution of Oceanography, Dr. University of California-San Diego, 9500 Gilman, La Jolla, CA, 92093, United States; Department of Earth and Environmental Sciences, Ludwig-Maximilians Universität, Theresienstrasse 41, 80333 München, Germany 5 A California; Coseismic deformation; Dislocation models; Dispersion characteristics; Local structure; Rayleigh-wave phase velocity; San Andreas Fault; Seismic event; Strain-meter; Teleseismic earthquakes; Vertical ground accelerations; Vertical strain, Interferometry; Optical fibers; Phase velocity; Seismology, Strain measurement, coseismic process; deformation; interferometer; optical instrument; phase velocity; Rayleigh wave; seismograph; sensor; teleseismic wave; wave velocity, California; Parkfield; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-77957729501&doi=10.1785%2f0120090333&partnerID=40&md5=4c727dcdf02ae0515c3c5c6c398fb901 cited By 11 J. Blum H. Igel M. Zumberge conference Uddin20101274 Gas hydrates are a potentially vast untapped source of natural gas. Recent numerical and field studies suggest the Mallik gas hydrate field in Canada's Mackenzie Delta may represent a technically producible and potentially economically viable reservoir of natural gas. Our initial reservoir simulations using a kinetic reaction approach indicate that gas evolution and transport within porous geologic reservoirs have a significant effect on fluid production characteristics, while field and laboratory data suggest that significant amounts of evolved gas can be trapped for some time within the reservoir, depending on the field operation. In mis work, we invoke modeling concepts extensively employed in quantifying gas ex-solution from very viscous oils to further assess the kinetic behaviour of gas hydrate ex-solution via depressurization. Here the gas bubbles can be categorized into three groups with explicit transport behaviour: small bubbles (water phase), large bubbles (immobile) and connected bubbles (or free gas). These concepts allow the development of a new set of kinetic reactions for hydrate dissociation: one representing the (possibly delayed) conversion of hydrate into water and dispersed gas bubble phases, and one representing the evolution from dispersed bubbles to connected bubbles. These reactions can effectively capture the non-equilibrium fluid flow behaviour observed in field production tests. For modeling of the transport phenomenon, we assumed two explicit mobility formulations, 1) trapped bubbles (no mobility) and a flowing water phase, and 2) large connected gas bubbles and flowing water (with relative mobility). Relative mobility can be estimated by using traditional grid block relative permeability curves. We then develop a simple mechanistic gas bubbles trapping tool as a function of Capillary Number, which can easily be incorporated into our numerical simulator. This entrapment of me non-wetting gas phase results in higher values of critical gas saturation. Two case studies based on alternative representations of a Mallik-like gas hydrate reservoir demonstrate that significant errors can result in reservoir modeling if these fluid transport phenomena are not adequately represented in numerical simulations. Aspects of the model developed here have been applied to history matching and prediction of natural gas recovery from clastic, sand-dominated reservoir at the Mallik Site. Copyright 2010, Society of Petroleum Engineers. 2010 English 9781617820427 10.2118/137439-ms Society of Petroleum Engineers - Canadian Unconventional Resources and International Petroleum Conference 2010 2 Society of Petroleum Engineers 1274-1303 Alberta Innovates, Canada; Geological Survey of Canada, Canada; Computer Modeling Group, Canada Bubbles (in fluids); Flow of fluids; Gas hydrates; Gas oils; Gases; Gasoline; Hydration; Kinetics; Natural gas; Natural gasoline plants; Petroleum reservoirs; Resource valuation; Transport properties; Wetting, Critical gas saturation; Gas hydrate reservoir; Hydrate dissociation; Natural gas hydrate reservoir; Natural gas recoveries; Numerical simulators; Relative permeability curves; Reservoir simulation, Natural gas fields https://www.scopus.com/inward/record.uri?eid=2-s2.0-79952918156&doi=10.2118%2f137439-ms&partnerID=40&md5=5c396d54fdbb0501b049751b40e6a0db cited By 0 M. Uddin F. Wright D. Coombe article Conze201030 2010 English 18168957 10.5194/sd-9-30-2010 Scientific Drilling Integrated Ocean Drilling Program 30-31 Operational Support Group ICDP, GFZ German Research Centre for Geosciences, Telegrafenberg, D-14473 Potsdam, Germany; Smartcube GmbH Berlin, Puschkinallee 48, D-12435 Berlin, Germany; Andrill Science Management Office, 126 Bessey Hall, Lincoln, United States; University of Nebraska-Lincoln, P.O. Box 880851, Loncoln, NE 68588-0341, United States; University of Illinois at Chicago, Electronic Visualization Laboratory, United States; MARUM, University of Bremen, Leobener Str., D-28359 Bremen, Germany; British Geological Survey Edinburgh, ESO - ECORD Science Operator, Murchison House, West Mains Road, Edinburgh EH9 3LA, Scotland, United Kingdom; University of Cologne, Institute of Geology and Mineralogy, Zuelpicher Str. 49a, D-50674 Koeln, Germany 9 https://www.scopus.com/inward/record.uri?eid=2-s2.0-78651586654&doi=10.5194%2fsd-9-30-2010&partnerID=40&md5=237a45dcde4ac7adc770963c7a2d903f cited By 2 R. Conze F. Krysiak J. Reed Y.-C. Chen H.-J. Wallrabe-Adams C. Graham V. Wennrich article Goderis2010395 Fifteen impactites from various intervals within the Eyreville cores of the Chesapeake Bay impact structure were sampled to measure siderophile element concentrations. The sampled intervals include basement-derived rocks with veins, polymict impact breccias and associated rocks, and crater-fill sediments. The platinum group element (PGE) concentrations obtained are generally low (e.g., iridium concentrations less than 0.1 ng/g) and are fractionated relative to chondrites. There is no clear distinction in concentration between the different impactite units. So far in the Chesapeake Bay material, only the impact melt rocks from the 823-m-deep Cape Charles test hole, drilled over the central uplift of the structure, have generated a bulk chondritic signature of 0.01-0.1 wt% meteoritic contribution based on a mixing model of 187 Os/ 188 Os isotopic ratios and Os concentrations. However, none of the samples studied shows PGE abundances that enable identification of the type of projectile responsible for the formation of the structure. Hence, it is at present not possible to link the Chesapeake Bay impact to the proposed ordinary chondrite falls by projectiles recorded for other late Eocene craters, namely the 100-km-diameter Popigai impact structure in Siberia and 7.5-km-diameter Wanapitei structure in Canada. The absence of a clear projectile signature hinders further discussions on the existence and the nature of the late Eocene shower event (asteroid versus comet). © 2010 The Geological Society of America. All rights reserved. 2010 10.1130/2010.2465(20) Special Paper of the Geological Society of America 465 395-409 Earth System Science, Vrije Universiteit Brussel, Pleinlaan 2, BE-1050 Brussels, Belgium; Department of Analytical Chemistry, Universiteit Gent, Krijgslaan 281-S12, BE-9000 Ghent, Belgium; Department of Geology, Katholieke Universiteit Leuven, Celestijnenlaan 200E, BE-3001 Heverlee, Belgium https://www.scopus.com/inward/record.uri?eid=2-s2.0-78650937770&doi=10.1130%2f2010.2465%2820%29&partnerID=40&md5=2f27c59a6b7c2e5b1ab814394c3a679c cited By 10 S. Goderis J. Hertogen F. Vanhaecke Ph. Claeys article Wilke20103051 The Balkans is a biogeographically highly diverse region and a worldwide hotspot of endemic freshwater diversity. A substantial part of this diversity is attributed to well recognized and potential ancient lakes in its southwestern part. However, despite considerable research efforts, faunal relationships among those lakes are not well understood. Therefore, genetic information from native representatives of the mussel genus Dreissena is here used to test the biogeographical zonation of the southwestern Balkans, to relate demographic changes to environmental changes, to assess the degree of eco-insularity, to reconstruct their evolutionary history, and to explore the potential of native taxa for becoming invasive. Phylogeographical and population genetic analyses indicate that most studied populations belong to two native species: D. presbensis (including the distinct genetic subgroup from Lake Ohrid, "D. stankoviciquot;) and D. blanci. In addition, the first confirmed record of invasive D. polymorpha in the southwestern Balkan is presented. The distribution of native Dreissena spp. generally coincides with the biogeographical zonations previously suggested based on fish data. However, there is disagreement on the assignment of the ancient lakes in the area to respective biogeographical regions. The data for Lake Ohrid are not conclusive. A closer biogeographical connection to lakes of the Vardar region and possibly the northern Ionian region is, however, suggested for Lake Prespa. The reconstruction of the evolutionary history of Dreissena spp. suggests that populations underwent demographic and spatial expansions in the recent past. Expansions started around 320 000-300 000 years ago in "D. stankovici", 160 000-140 000 years ago in D. blanci, and 110 000-70 000 years ago in D. presbensis. These time frames are discussed within the context of available paleogeological data for lakes Ohrid and Prespa. It is suggested that regional environmental changes may have had pronounced effects on the population histories of native Dreissena spp., though the high buffer capacity of Lake Ohrid may have lessened these effects in "D. stankovici". In addition, local events influencing individual lakes had very likely considerable effects on the demographic histories of Dreissena spp. as well. The observed patterns of immigration and emigration in and out of ancient lakes may suggest that limited gene flow enabled the survival of few isolated subpopulations and that later on eco-insularity (selective advantages of locally adopted groups) may have prevented excessive hybridization and sympatry of closely related taxa. As for the potential invasiveness of native Dreissena spp., the inferred spatial expansions are not human-mediated and all taxa still appear to be restricted to their native ranges. A concern, however, is that today D. presbensis and D. blanci also occur in artificial water bodies, and that invasive D. polymorpha has reached the area. © Author(s) 2010. Article 2010 English 17264189 10.5194/bg-7-3051-2010 Biogeosciences 7 3051 – 3065 10 Balkans; Lake Mikri Prespa; Lake Ohrid; Dreissena; Dreissena polymorpha; Dreissena stankovici; bivalve; extinction; freshwater environment; genetic analysis; historical perspective; native species; paleoecology; reconstruction; species diversity; sympatry; zoogeography https://www.scopus.com/inward/record.uri?eid=2-s2.0-77957989147&doi=10.5194%2fbg-7-3051-2010&partnerID=40&md5=4efb6f2b1e722322468a72d60aca240c Cited by: 43; All Open Access, Gold Open Access, Green Open Access T. Wilke R. Schultheiß C. Albrecht N. Bornmann S. Trajanovski T. Kevrekidis article Goderis2010395 Fifteen impactites from various intervals within the Eyreville cores of the Chesapeake Bay impact structure were sampled to measure siderophile element concentrations. The sampled intervals include basement-derived rocks with veins, polymict impact breccias and associated rocks, and crater-fill sediments. The platinum group element (PGE) concentrations obtained are generally low (e.g., iridium concentrations less than 0.1 ng/g) and are fractionated relative to chondrites. There is no clear distinction in concentration between the different impactite units. So far in the Chesapeake Bay material, only the impact melt rocks from the 823-m-deep Cape Charles test hole, drilled over the central uplift of the structure, have generated a bulk chondritic signature of 0.01-0.1 wt% meteoritic contribution based on a mixing model of 187 Os/ 188 Os isotopic ratios and Os concentrations. However, none of the samples studied shows PGE abundances that enable identification of the type of projectile responsible for the formation of the structure. Hence, it is at present not possible to link the Chesapeake Bay impact to the proposed ordinary chondrite falls by projectiles recorded for other late Eocene craters, namely the 100-km-diameter Popigai impact structure in Siberia and 7.5-km-diameter Wanapitei structure in Canada. The absence of a clear projectile signature hinders further discussions on the existence and the nature of the late Eocene shower event (asteroid versus comet). © 2010 The Geological Society of America. All rights reserved. 2010 English 00721077 10.1130/2010.2465(20) Special Paper of the Geological Society of America 465 Geological Society of America 395-409 Earth System Science, Vrije Universiteit Brussel, Pleinlaan 2, BE-1050 Brussels, Belgium; Department of Analytical Chemistry, Universiteit Gent, Krijgslaan 281-S12, BE-9000 Ghent, Belgium; Department of Geology, Katholieke Universiteit Leuven, Celestijnenlaan 200E, BE-3001 Heverlee, Belgium Infill drilling; Meteor impacts; Meteorites; Projectiles, Chesapeake Bay; Chesapeake bay impact structures; Impact structures; Isotopic ratios; Mixing models; Ordinary chondrites; Platinum group elements; Siderophile elements, Core drilling, chondrite; crater; impact structure; impactite; isotopic ratio; meteorite; platinum group element; siderophile element, Canada; Chesapeake Bay; Ontario [Canada]; United States; Wanapitei Lake https://www.scopus.com/inward/record.uri?eid=2-s2.0-78650937770&doi=10.1130%2f2010.2465%2820%29&partnerID=40&md5=2f27c59a6b7c2e5b1ab814394c3a679c cited By 10 S. Goderis J. Hertogen F. Vanhaecke Ph. Claeys article French2010123 In the geological sciences it has only recently been recognized how important the process of impact cratering is on a planetary scale, where it is commonly the most important surface-modifying process. On the Moon and other planetary bodies that lack an appreciable atmosphere, meteorite impact craters are well preserved, and they can commonly be recognized from morphological characteristics, but on Earth complications arise as a consequence of the weathering, obliteration, deformation, or burial of impact craters and the projectiles that formed them. These problems made it necessary to develop diagnostic criteria for the identification and confirmation of impact structures on Earth. Diagnostic evidence for impact events is often present in the target rocks that were affected by the impact. The conditions of impact produce an unusual group of melted, shocked, and brecciated rocks, some of which fill the resulting crater, and others which are transported, in some cases to considerable distances from the source crater. Only the presence of diagnostic shock-metamorphic effects and, in some cases, the discovery of meteorites, or traces thereof, is generally accepted as unambiguous evidence for an impact origin. Shock deformation can be expressed in macroscopic form (shatter cones) or in microscopic forms (e.g., distinctive planar deformation features [PDFs] in quartz). In nature, shock-metamorphic effects are uniquely characteristic of shock levels associated with hypervelocity impact. The same two criteria (shock-metamorphic effects or traces of the impacting meteorite) apply to distal impact ejecta layers, and their presence confirms that materials found in such layers originated in an impact event at a possibly still unknown location. As of 2009 about 175 impact structures have been identified on Earth based on these criteria. A wide variety of shock-metamorphic effects has been identified, with the best diagnostic indicators for shock metamorphism being features that can be studied easily by using the polarizing microscope. These include specific planar microdeformation features (planar fractures [PFs], PDFs), isotropization (e.g., formation of diaplectic glasses), and phase changes (high pressure phases; melting). The present review provides a detailed discussion of shock effects and geochemical tracers that can be used for the unambiguous identification of impact structures, as well as an overview of doubtful criteria or ambiguous lines of evidence that have erroneously been applied in the past. © 2009 Elsevier B.V. All rights reserved. 2010 10.1016/j.earscirev.2009.10.009 Earth-Science Reviews 98 123-170 Department of Paleobiology, Smithsonian Institution, PO Box 37012, Washington, DC 20013-7012, United States; Department of Lithospheric Research, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria 1-2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-75449090246&doi=10.1016%2fj.earscirev.2009.10.009&partnerID=40&md5=966d6b872a555d79d536dcb18f91cc95 cited By 369 B.M. French C. Koeberl article Ferrière2010254 The 1.07. Myr old Bosumtwi impact structure (Ghana), excavated in 2.1-2.2. Gyr old supracrustal rocks of the Birimian Supergroup, was drilled in 2004. Here, we present single crystal U-Pb zircon ages from a suevite and two meta-graywacke samples recovered from the central uplift (drill core LB-08A), which yield an upper Concordia intercept age of ca 2145 ± 82 Ma, in very good agreement with previous geochronological data for the West African Craton rocks in Ghana. Whole rock Rb-Sr and Sm-Nd isotope data of six suevites (five from inside the crater and one from outside the northern crater rim), three meta-graywacke, and two phyllite samples from core LB-08A are also presented, providing further insights into the timing of the metamorphism and a possibly related isotopic redistribution of the Bosumtwi crater rocks. Our Rb-Sr and Sm-Nd data show also that the suevites are mixtures of meta-greywacke and phyllite (and possibly a very low amount of granite). A comparison of our new isotopic data with literature data for the Ivory Coast tektites allows to better constrain the parent material of the Ivory Coast tektites (i.e., distal impactites), which is thought to consist of a mixture of metasedimentary rocks (and possibly granite), but with a higher proportion of phyllite (and shale) than the suevites (i.e., proximal impactites). When plotted in a Rb/Sr isochron diagram, the sample data points (n=29, including literature data) scatter along a regression line, whose slope corresponds to an age of 1846 ± 160 Ma, with an initial Sr isotope ratio of 0.703 ± 0.002. However, due to the extensive alteration of some of the investigated samples and the lithological diversity of the source material, this age, which is in close agreement with a possible "metamorphic age" of ~. 1.8-1.9. Ga tentatively derived from our U-Pb dating of zircons, is difficult to consider as a reliable metamorphic age. It may perhaps reflect a common ancient source whose Rb-Sr isotope systematics has not basically been reset on the whole rock scale during the Bosumtwi impact event, or even reflect another unknown geologic event. © 2010 Elsevier B.V. Article 2010 English 00092541 10.1016/j.chemgeo.2010.05.016 Chemical Geology 275 254 – 261 3-4 Cote d'Ivoire; Ghana; comparative study; country rock; geochronology; graywacke; impact structure; impactite; isotopic composition; isotopic ratio; lithology; metamorphism; neodymium isotope; phyllite; strontium isotope; tektite; uranium-lead dating; zircon https://www.scopus.com/inward/record.uri?eid=2-s2.0-77954533360&doi=10.1016%2fj.chemgeo.2010.05.016&partnerID=40&md5=c79ace79800cf950f45b8c7f4b47ce88 Cited by: 7; All Open Access, Green Open Access, Hybrid Gold Open Access Ludovic Ferrière Christian Koeberl Martin Thöni Chen Liang article Fischer2010665 A swarm of earthquakes of magnitudes up to ML = 3.8 stroke the region of West Bohemia/Vogtland (border area between Czechia and Germany) in October 2008. It occurred in the Nový Kostel focal zone, where also all recent earthquake swarms (1985/1986, 1997, and 2000) took place, and was striking by a fast sequence of macroseismically observed earthquakes. We present the basic characteristics of this swarm based on the observations of a local network WEBNET (West Bohemia seismic network), which has been operated in the epicentral area, on the Czech territory. The swarm was recorded by 13 to 23 permanent and mobile WEBNET stations surrounding the swarm epicenters. In addition, a part of the swarm was also recorded by strong-motion accelerometers, which represent the first true accelerograms of the swarm earthquakes in the region. The peak ground acceleration reached 0.65 m/s2. A comparison with previous earthquake swarms indicates that the total seismic moments released during the 1985/1986 and 2008 swarms are similar, of about 4E16 Nm, and that they represent the two largest swarms that occurred in the West Bohemia/ Vogtland region since the ML = 5.0 swarm of 1908. Characteristic features of the 2008 swarm are its short duration (4 weeks) and rapidity and, consequently, the fastest seismic moment release compared to previous swarms. Up to 25,000 events in the magnitude range of 0.5 < ML < 3.8 were detected using an automatic picker. A total of nine swarm phases can be distinguished in the swarm, five of them exceeding the magnitude level of 2.5. The magnitude-frequency distribution of the complete 2008 swarm activity shows a b value close to 1. The swarm hypocenters fall precisely on the same fault portion of the Nový Kostel focal zone that was activated by the 2000 swarm (ML ≤ 3. 2) in a depth interval from 6 to 11 km and also by the 1985/1986 swarm (ML ≤ 4.6). The steeply dipping fault planes of the 2000 and 2008 swarms seem to be identical considering the location error of about 100 m. Furthermore, focal mechanisms of the 2008 swarm are identical with those of the 2000 swarm, both matching an average strike of 170° and dip of 80° of the activated fault segment. An overall upward migration of activity is observed with first events at the bottom and last events at the top of the of the activated fault patch. Similarities in the activated fault area and in the seismic moments released during the three largest recent swarms enable to estimate the seismic potential of the focal zone. If the whole segment of the fault plane was activated simultaneously, it would represent an earthquake of ML ~5. This is in good agreement with the estimates of the maximum magnitudes of earthquakes that occurred in the West Bohemia/Vogtland region in the past. © 2010 Springer Science+Business Media B.V. Article 2010 English 13834649 10.1007/s10950-010-9189-4 Journal of Seismology 14 665 – 682 4 Bohemia; Czech Republic; Germany; Vogtland; earthquake epicenter; earthquake event; earthquake magnitude; earthquake mechanism; earthquake swarm; fault plane; focal mechanism; peak acceleration; seismic moment; seismicity; strong motion https://www.scopus.com/inward/record.uri?eid=2-s2.0-77957229959&doi=10.1007%2fs10950-010-9189-4&partnerID=40&md5=db48c0f4fc254d1bcc35e349ca54d64d Cited by: 74; All Open Access, Green Open Access Tomáš Fischer Josef Horálek Jan Michálek Alena Boušková article Fritz20101017 Millennial-scale climate variation during the Last Glacial period is evident in many locations worldwide, but it is unclear if such variation occurred in the interior of tropical South America, and, if so, how the low-latitude variation was related to its high-latitude counterpart. A high-resolution record, derived from the deep drilling of sediments on the floor of Lake Titicaca in the southern tropical Andes, is presented that shows clear evidence of millennial-scale climate variation between ∼60 and 20 ka BP. This variation is manifested by alternations of two interbedded sedimentary units. The two units have distinctive sedimentary, geochemical, and paleobiotic properties that are controlled by the relative abundance of terrigenous or nearshore components versus pelagic components. The sediments of more terrigenous or nearshore nature likely were deposited during regionally wetter climates when river transport of water and sediment was higher, whereas the sediments of more pelagic character were deposited during somewhat drier climates regionally. The majority of the wet periods inferred from the Lake Titicaca sediment record are correlated with the cold events in the Greenland ice cores and North Atlantic sediment cores, indicating that increased intensity of the South American summer monsoon was part of near-global scale climate excursions. © 2010 Elsevier Ltd. All rights reserved. Article 2010 10.1016/j.quascirev.2010.01.001 Quaternary Science Reviews 29 1017 – 1024 7-8 Andes; Lake Titicaca; Climatology; Glacial geology; Salinity measurement; Tropics; Climate variability; Climate variation; Deep drilling; Global scale; Greenland; High resolution; Ice core; Last glacial period; Nearshores; North Atlantic; Relative abundance; River transports; Sediment core; Sedimentary units; South America; Summer monsoon; Tropical Andes; Wet period; climate variation; deep drilling; lacustrine deposit; Last Glacial; paleoclimate; resolution; sedimentation; terrigenous deposit; Sedimentology https://www.scopus.com/inward/record.uri?eid=2-s2.0-77649340434&doi=10.1016%2fj.quascirev.2010.01.001&partnerID=40&md5=f0a249b7cf6b5b14c713d24649af2112 Cited by: 35; All Open Access, Green Open Access S.C. Fritz P.A. Baker E. Ekdahl G.O. Seltzer L.R. Stevens article Liu2010247 Granitic leucosome and pegmatite are widely distributed within biotite-bearing orthogneiss in the northern part of the Sulu ultrahigh-pressure (UHP) metamorphic terrane, eastern China. A combined study of mineral inclusions, cathodoluminescence (CL) images, U-Pb SHRIMP dates, and in situ trace element and Lu-Hf isotope analyses of zircons provided insight into the nature and timing of partial melting in these rocks. Zircon grains separated from biotite-bearing orthogneiss typically have three distinct domains: (1) pre-metamorphic (magmatic) cores with Qtz. +. Kfs. +. Pl. +. Ap inclusions, which record a Neoproterozoic protolith age of ~ 790. Ma, (2) mantles with Coe. +. Phe. +. Ap inclusions that record Triassic UHP age at 227 ± 3. Ma, and (3) narrow rims with quartz inclusions that record HP granulite-facies retrograde metamorphism at ~ 210 ± 3. Ma. In contrast, zircons separated from granitic leucosome have only two distinct domains: (1) the central UHP areas with Coe. +. Phe. +. Ap inclusions record Triassic UHP age of 227 ± 3. Ma, and (2) outer magmatic areas with Qtz. +. Kfs. +. Ab. +. Ap inclusions that record partial melting time of 212 ± 2. Ma. Zircons separated from pegmatite contain mineral inclusions of Qtz. +. Kfs. +. Ap and show regular magmatic zoning from centre to edge. The centres record partial melting time of 212 ± 2. Ma in line with the outer domains of granitic leucosome, whereas the edges give a younger age of 201 ± 2. Ma related to Pb loss and partial recrystallization during late Triassic regional amphibolite-facies retrogression. These data indicate that partial melting in the north Sulu UHP gneissic rocks took place during post-UHP, retrograde HP granulite-facies metamorphism. Pre-metamorphic (magmatic) zircon cores from biotite-bearing orthogneiss give uniform 176Hf/177Hf of 0.28187±0.00003 (2SD; standard deviation) corresponding to εHf(790) and Hf model ages (TDM2) of about -16.3 and 2.41Ga, respectively. This is consistent with the generation of its protolith by reworking of Paleoproterozoic to late Archean crust. In contrast, UHP zircon domains from biotite-bearing orthogneiss and granitic leucosome are characterized by distinct trace element composition with low Lu/Hf (<0.006), low Th/U (<0.1) and considerably higher, 176Hf/177Hf (0.28233±0.00002; 2SD) than the pre-metamorphic cores. The uniform but significantly different Hf isotope composition between the UHP (εHf(227)=-14.6±0.8; 2SD) and pre-metamorphic (-Hf(227)=-27.7) domains indicates equilibration of the Lu-Hf isotope system only within the UHP metamorphic mineral assemblage. The disequilibrium between whole rock and UHP zircon suggests that about two thirds of the whole rock Hf retained in the pre-metamorphic zircon domains. Zircon domains crystallized during partial melting at 212Ma in granitic leucosome and pegmatites have a Hf isotope composition indistinguishable from that of the UHP zircon domains. This suggests that only Hf (and Zr) equilibrated during UHP metamorphism was remobilized during partial melting while pre-metamorphic zircon remained stable or was not accessible. In contrast, the magmatic zircon edges from pegmatite have somewhat lower 176Hf/177Hf (~0.28216) and εHf(t) (-17.6±1.2; 2SD) indicating some release of less radiogenic Hf for instance by dissolution of pre-metamorphic zircon during late regional amphibolite-facies retrogression. © 2010 Elsevier B.V. Article 2010 English 00244937 10.1016/j.lithos.2010.03.002 Lithos 117 247 – 268 1-4 China; Sulu Belt; biotite; granite; granulite facies; hafnium; inclusion; isotopic analysis; isotopic composition; partial melting; pegmatite; rare earth element; retrograde metamorphism; terrane; trace element; Triassic; uranium-lead dating; zircon https://www.scopus.com/inward/record.uri?eid=2-s2.0-77952591837&doi=10.1016%2fj.lithos.2010.03.002&partnerID=40&md5=f5d61d6f595842b415c197cf7f703933 Cited by: 134 Fulai Liu Paul T. Robinson Axel Gerdes Huaimin Xue Pinghua Liu Juhn G. Liou article Jin20101057 Strontium (Sr) concentrations and isotopic ratios have been measured in a series of water and rock samples from most of the major tributaries of the Lake Qinghai basin on the north-eastern Tibetan Plateau. Dissolved Sr and 87Sr/86Sr show ranges of 488-12 240 nmol/l and 0·710497-0·716977, respectively. These data, together with measurements of major cations and anions in rivers and their tributaries and various lithologies of the catchment, were used to determine the contributions of Sr and its isotopic expense to rivers and lakes. Our results demonstrate that the chemical components and 87Sr/86Sr ratios of the alkaline waters are derived from mixing of carbonate and silicate sources, with the former contributing 72 ± 18% dissolved Sr to rivers. The difference in tributary compositions stems from the lithology of different river systems and low weathering intensity under a semi-arid condition. Variation in 87Sr/86Sr ratios places constraint on the Sr-isotopic compositions of the main tributaries surrounding Lake Qinghai. The water chemistry of the Buha River, the largest river within the catchment underlain by the late Paleozoic marine limestone and sandstones, dominates Sr isotopic composition of the lake water, being buffered by the waters from the other rivers and probably by groundwater. However, the characteristic chemical composition of the lake itself differs remarkably from the rivers, which can be attributed to precipitation of authigenic carbonates (low-magnesium calcite, aragonite, and dolomite), though this does not impact the Sr isotope signature, which may remain a faithful indicator in paleo-records. Regarding the potential role of groundwater input within the Lake Qinghai systems in the water budget and water chemistry, we have also determined the Sr concentration and 87Sr/S6Sr ratio of groundwater from diverse environments. This has allowed us to further constrain the Sr isotope systematic of this source. A steady-state calculation gives an estimate for the groundwater flux of 0·19 ± 0·03 x 108 m3/yr, accounting for about 8% of contemporary lake Sr budget. © 2010 John Wiley & Sons, Ltd. Article 2010 English 10969837 10.1002/esp.1964 Earth Surface Processes and Landforms 35 1057 – 1070 9 China; Qinghai; Qinghai Lake; Qinghai-Xizang Plateau; Budget control; Carbonate minerals; Catchments; Dissolution; Groundwater; Indicators (chemical); Isotopes; Lakes; Lithology; Magnesium; Precipitation (chemical); Rivers; Runoff; Silicates; Soil mechanics; Weathering; Alkaline water; Authigenic carbonates; Budget; Chemical component; Chemical compositions; Eastern Tibetan plateau; Groundwater fluxes; Isotope signatures; Isotopic composition; Isotopic ratios; Lake waters; Late Paleozoic; Magnesium calcite; River systems; Rivers and lakes; Rock sample; Semi-arid conditions; Sr fluxes; Tibetan Plateau; Water budget; Water chemistry; catchment; chemical weathering; concentration (composition); isotopic composition; isotopic ratio; strontium isotope; surface water; water budget; water chemistry; Strontium https://www.scopus.com/inward/record.uri?eid=2-s2.0-77954559864&doi=10.1002%2fesp.1964&partnerID=40&md5=4728a2b26b858b62bc9b13329e64fc80 Cited by: 28 Zhangdong Jin Sumin Wang Fei Zhang Yuewei Shi conference Zoback201069 Over the past fifteen years,my colleagues and I have developed a suite of techniques for determination of the full stress tensor in arbitrarily- orientedwells and boreholes utilizing observations of non-catastrophic failures of the wellbore wall - compressive failures, drilling-induced tensile fractures and stress perturbations associated with slip on faults cutting through thewellbore. While these techniques have had extensive application in the petroleum industry, they have also been used in core holes drilled from excavations in mines to yield information about the state of stress within, and beyond, the area affected by the stress concentration surrounding the excavation. When possible, hydraulic fracturing is used to provide independent information about the magnitude of the least principal stress, but is not used to estimate the maximum horizontal principal stress. In this paper we review both the conceptual elements of this methodology and two challenging case studies. The first involves determination of the state of stress following the drilling of the first phase of the SAFOD project, a scientific borehole drilled through the San Andreas Fault in central California. The second involves determination of the state of stress in the crust surrounding a very deep mine is South Africa. These case studies document how observations of wellbore failure in deviated wells yield consistent stress orientations and magnitudes over appreciable depth ranges. © 2010 Taylor & Francis Group, London. 2010 English 9780415601658 Rock Stress and Earthquakes - Proceedings of the 5th International Symposium on In-Situ Rock Stress 69-76 Department of Geophysics, Stanford University, Stanford, CA, United States; Conoco-Phillips, Houston, TX, United States; Shell International Exploration and Production, Houston, TX, United States California; Compressive failure; Conceptual elements; Core hole; Deep mines; Deep wells; Depth range; Deviated wells; Drilling-induced tensile fractures; Least principal stress; Maximum horizontal principal stress; San Andreas fault; South Africa; State of stress; Stress orientations; Stress perturbations; Stress tensors; Wellbore, Boring; Deflected boreholes; Hydraulic fracturing; Oil field equipment; Research; Stress concentration; Strike-slip faults; Tensors, Yield stress https://www.scopus.com/inward/record.uri?eid=2-s2.0-84860167342&partnerID=40&md5=6d2f5ae4d0f8854dbfa7391112953cc3 cited By 2 M.D. Zoback P. Paul A. Lucier article Lassila2010178 P- and S-wave propagation velocities in dry mica schist samples obtained from the Outokumpu deep drill hole in Eastern Finland were measured under uniaxial compression in a custom built measurement device. At 300 MPa pressure the obtained velocities (5520 ± 130) m/s and (3270 ± 60) m/s, for P- and S-waves, respectively, agreed with those measured under triaxial compression, (5530 ± 200) m/s and (3300 ± 90) m/s. The increase in Vp with uniaxial pressure was steeper, whereas this was not the case with Vs. These results indicate that ultrasound velocity measurements can be performed under uniaxial compression without the need to alter the cylindrical geometry of a borehole sample. Results obtained with the device can improve the interpretation of seismic crustal structure maps by providing seismic velocity data of the Outokumpu drill core as well as seismic impedances and reflection coefficients measured under crustal conditions. © 2010 Elsevier B.V. Article 2010 English 09269851 10.1016/j.jappgeo.2010.09.001 Journal of Applied Geophysics 72 178 – 183 3 Finland; Ita Suomen; Outokumpu; Core drilling; Cylinders (shapes); Mica; Rock drills; Seismology; Shear waves; Silicate minerals; Ultrasonic velocity; Ultrasonic velocity measurement; Ultrasonics; Wave propagation; Crustal structure; Cylindrical geometry; Drill core; Drill hole; Eastern Finland; Fennoscandian Shields; Measurement device; Mica schists; P- and S-waves; Reflection coefficients; Seismic impedance; Seismic velocities; Triaxial compression; Triaxial loading; Ultrasound; Uni-axial compression; Uniaxial pressures; Wave propagation velocities; compression; crustal structure; data interpretation; geometry; P-wave; S-wave; seismic reflection; seismic velocity; uniaxial strength; wave propagation; Velocity https://www.scopus.com/inward/record.uri?eid=2-s2.0-78649477486&doi=10.1016%2fj.jappgeo.2010.09.001&partnerID=40&md5=c7f60e26e26acc303ce8e3a6a074c1d2 Cited by: 10 I. Lassila R. Karlqvist T. Elbra F.K. Gates L.J. Pesonen E. Hæggström conference Bellefleur20101491 Three internationally-partnered research well programs in 1998, 2002, and 2007-08 studied the Mallik gas hydrate accumulation in the Mackenzie Delta, Canada, and have allowed successful extraction of subpermafrost core samples with significant amount of hydrates. Gas hydrate bearing intervals were logged with a comprehensive suite of tools and their producibility was tested in 2002 using thermal stimulation and in 2007/08 using depressurization techniques. Thus, the Mallik gas hydrates are well-characterized and are ideal targets for testing geophysical imaging techniques. Here, we apply acoustic impedance inversion to 3D seismic data acquired over the Mallik area to characterize gas hydrate occurrences and to help define their spatial extent away from well control. The inversion method converts reflections into acoustic impedances from which velocity and hydrate saturation were estimated. The extent and geometry of the two lower hydrate zones were mapped with high confidence and show a distribution controlled by local geology. Correlation between the uppermost hydrate zone and the 3D seismic data could not be established with confidence, because of geological heterogeneity and/or inappropriate seismic imaging. The heterogeneity of the Mallik gas hydrates was parameterized following a method based on multivariate conditional stochastic simulation of well-logging data. Following this method, multi-dimensional heterogeneous models of petrophysical properties (Vp, Vs and density) of hydrate-bearing sediments were constructed and used to assess effects of heterogeneity on gas hydrate volume estimates. Models including small-scale heterogneities provide volume estimate nearly an order of magnitude lower than earlier estimates which did not include effect of heterogeneity. ©Her Majesty the Queen in Right of Canada 2010. 2010 English 9781617820427 10.2118/137499-ms Society of Petroleum Engineers - Canadian Unconventional Resources and International Petroleum Conference 2010 2 Society of Petroleum Engineers 1491-1499 Geological Survey of Canada, Canada; University of Toronto, Canada Acoustic impedance; Gases; Gasoline; Geology; Geophysical prospecting; Hydration; Imaging techniques; Petrophysics; Resource valuation; Seismic response; Seismic waves; Stochastic control systems; Stochastic models; Stochastic systems; Well logging; Well testing, Acoustic impedance inversion; Geological heterogeneities; Heterogeneous models; Hydrate accumulations; Hydrate bearing sediments; Permafrost environment; Petrophysical properties; Stochastic simulations, Gas hydrates https://www.scopus.com/inward/record.uri?eid=2-s2.0-79952943981&doi=10.2118%2f137499-ms&partnerID=40&md5=7a0acc7417e622b83810609d03be881b cited By 2 G. Bellefleur M. Riedel J. Huang B. Milkereit T. Brent article Hurwitz2010233 Long Valley Caldera in eastern California formed 0.76Ma ago in a cataclysmic eruption that resulted in the deposition of 600km3 of Bishop Tuff. The total current heat flow from the caldera floor is estimated to be ~290MW, and a geothermal power plant in Casa Diablo on the flanks of the resurgent dome (RD) generates ~40MWe. The RD in the center of the caldera was uplifted by ~80cm between 1980 and 1999 and was explained by most models as a response to magma intrusion into the shallow crust. This unrest has led to extensive research on geothermal resources and volcanic hazards in the caldera. Here we present results from precise, high-resolution, temperature-depth profiles in five deep boreholes (327-1,158m) on the RD to assess its thermal state, and more specifically 1) to provide bounds on the advective heat transport as a guide for future geothermal exploration, 2) to provide constraints on the occurrence of magma at shallow crustal depths, and 3) to provide a baseline for future transient thermal phenomena in response to large earthquakes, volcanic activity, or geothermal production. The temperature profiles display substantial non-linearity within each profile and variability between the different profiles. All profiles display significant temperature reversals with depth and temperature gradients &lt;50°C/km at their bottom. The maximum temperature in the individual boreholes ranges between 124.7°C and 129.5°C and bottom hole temperatures range between 99.4°C and 129.5°C. The high-temperature units in the three Fumarole Valley boreholes are at the approximate same elevation as the high-temperature unit in borehole M-1 in Casa Diablo indicating lateral or sub-lateral hydrothermal flow through the resurgent dome. Small differences in temperature between measurements in consecutive years in three of the wells suggest slow cooling of the shallow hydrothermal flow system. By matching theoretical curves to segments of the measured temperature profiles, we calculate horizontal groundwater velocities in the hydrothermal flow unit under the RD that range from 1.9 to 2.8m/yr, which corresponds to a maximum power flowing through the RD of 3-4MW. The relatively low temperatures and large isothermal segments at the bottom of the temperature profiles are inconsistent with the presence of magma at shallow crustal levels. © 2010. 2010 English 03770273 10.1016/j.jvolgeores.2010.08.023 Journal of Volcanology and Geothermal Research 198 233-240 U.S. Geological Survey, 345 Middlefield Rd., Menlo Park, CA, United States; U.S. Geological Survey, PO 1360, Carnelian Bay, CA, United States 1-2 Caldera; Geothermal; Heat flows; Hydrothermal; Long Valley; Resurgent dome; Temperature log, Boreholes; Domes; Geothermal energy; Geothermal fields; Geothermal logging; Geothermal power plants; Geothermal prospecting; Groundwater; Heat transfer; Temperature control; Volcanoes; Wells, Thermal logging, caldera; crust; dome; geothermal power; groundwater flow; heat flow; hydrothermal system; igneous intrusion; temperature profile; thermal regime; uplift, California; Long Valley Caldera; United States, Calluna vulgaris https://www.scopus.com/inward/record.uri?eid=2-s2.0-78650076069&doi=10.1016%2fj.jvolgeores.2010.08.023&partnerID=40&md5=aa555a6c79fc3b917dfbdab4f78d7c3a cited By 12 S. Hurwitz C.D. Farrar C.F. Williams article 2010precise 2010 Acta Petrologica Et Mineralogica 29 213-218 2 高翔 王平康 李秋英 王成善 高远 article Mountain201026 2010 English 18168957 10.2204/iodp.sd.10.03.2010 Scientific Drilling 26-34 Department of Earth and Planetary Sciences, Rutgers University, 610 Taylor Road, Piscataway, NJ 08854, United States; Géosciences, CNRS, Université Rennes1, Campus de Beaulieu, 35042 Rennes, France 10 https://www.scopus.com/inward/record.uri?eid=2-s2.0-78651570650&doi=10.2204%2fiodp.sd.10.03.2010&partnerID=40&md5=101ba64c6a4192f35f6cb3746bf4c775 cited By 15 G. Mountain J.-N. Proust article Reed20103083 Lake Ohrid is a site of global importance for palaeoclimate research. This study presents results of diatom analysis of a ca. 136 ka sequence, Co1202, from the northeast of the lake basin. It offers the opportunity to test diatom response across two glacial-interglacial transitions and within the Last Glacial, while setting up taxonomic protocols for future research. The results are outstanding in demonstrating the sensitivity of diatoms to climate change, providing proxy evidence for temperature change marked by glacial-interglacial shifts between the dominant planktonic taxa, Cyclotella fottii and C. ocellata, and exact correlation with geochemical proxies to mark the start of the Last Interglacial at ca. 130 ka. Importantly, diatoms show much stronger evidence in this site for warming during MIS3 than recorded in other productivity-related proxies, peaking at ca. 39 ka, prior to the extreme conditions of the Last Glacial maximum. In the light of the observed patterns, and from the results of analysis of early Holocene sediments from a second core, Lz1120, the lack of a response to Late Glacial and early Holocene warming from ca. 14.7-6.9 ka suggests the Co1202 sequence may be compromised during this phase. After ca. 7.4 ka, there is evidence for enhanced nutrient enrichment compared to the Last Interglacial, followed by a post-Medieval loss of diversity which is consistent with cooling, but not definitive. Taxonomically, morphological variability in C. fottii shows no clear trends linked to climate, but an intriguing change in central area morphology occurs after ca. 48.7 ka, coincident with a tephra layer. In contrast, C. ocellata shows morphological variation in the number of ocelli between interglacials, suggesting climatically-forced variation or evolutionary selection pressure. The application of a simple dissolution index does not track preservation quality very effectively, underlining the importance of diatom accumulation data in future studies. © 2010 Author(s). Article 2010 English 17264189 10.5194/bg-7-3083-2010 Biogeosciences 7 3083 – 3094 10 Albania; Lake Ohrid; Macedonia [Southern Europe]; Bacillariophyta; Cyclotella; Cyclotella ocellata; climate change; diatom; glacial-interglacial cycle; Holocene; Last Glacial; morphology; nutrient enrichment; paleoclimate; taxonomy; tephra https://www.scopus.com/inward/record.uri?eid=2-s2.0-77958037325&doi=10.5194%2fbg-7-3083-2010&partnerID=40&md5=5db8546facc33cafee43e41d37143937 Cited by: 39; All Open Access, Gold Open Access, Green Open Access J.M. Reed A. Cvetkoska Z. Levkov H. Vogel B. Wagner article melezhik2010great 2010 Scientific Drilling 9 Copernicus GmbH 23--29 Victor A Melezhik Aivo Lepland Alexander E Romashkin Dmitry V Rychanchik Melanie Mesli RE Finne Ronald Conze others article wang2010distribution 2010 Geochimica 39 469-478 L Wang ZG Song article Schulte20101214 The Cretaceous-Paleogene boundary ∼65.5 million years ago marks one of the three largest mass extinctions in the past 500 million years. The extinction event coincided with a large asteroid impact at Chicxulub, Mexico, and occurred within the time of Deccan flood basalt volcanism in India. Here, we synthesize records of the global stratigraphy across this boundary to assess the proposed causes of the mass extinction. Notably, a single ejecta-rich deposit compositionally linked to the Chicxulub impact is globally distributed at the Cretaceous-Paleogene boundary. The temporal match between the ejecta layer and the onset of the extinctions and the agreement of ecological patterns in the fossil record with modeled environmental perturbations (for example, darkness and cooling) lead us to conclude that the Chicxulub impact triggered the mass extinction. 2010 10.1126/science.1177265 Science 327 1214-1218 GeoZentrum Nordbayern, Universität Erlangen-Nürnberg, Schlossgarten 5, D-91054 Erlangen, Germany; Departamento de Ciencias de la Tierra, Instituto Universitario de Investigación de Ciencias Ambientales de Aragón, Universidad de Zaragoza, Pedro Cerbuna 12, E-50009 Zaragoza, Spain; Department of Earth Sciences, University of Cambridge, Cambridge CB2 3EO, United Kingdom; Department of Earth Sciences, University College London, Gower Street, London WC1E 6BT, United Kingdom; Department of Geosciences, Pennsylvania State University, University Park, PA 16802, United States; Institute for Geophysics, University of Texas at Austin, J. J. Pickle Research Campus, 10100 Burnet Road 196-ROC, Austin, TX 78759, United States; Earth System Science, Vrije Universiteit Brussel, Pleinlaan 2, B1050 Brussels, Belgium; Centre for Earth, Planetary, Space and Astronomical Research, Open University, Milton Keynes MK7 6AA, United Kingdom; Earth Science and Engineering, Imperial College London, London SW7 2BP, United Kingdom; Institut für Planetologie, Universität Münster, D-48149 Münster, Germany; Department of Lithospheric Research, University of Vienna, Althanstrasse 14, A1090 Vienna, Austria; Tsunami Engineering Laboratory, Graduate School of Engineering, Tohoku University, 6-6-11-1106 Aoba, Aramaki, Sendai 980-8579, Japan; Programa de Geología de Exploración y Explotación, Dirección de Investígacìón y Posgrado, Instituto Mexicano Del Petróleo, Eje Lázaro Cárdenas No. 152, C. P. 07730, México City, Mexico; Earth Sciences Sector, Natural Resources Canada, Ottawa, ON K1A OE4, Canada; Research and Collections Division, Denver Museum of Nature and Science, 2001 Colorado Boulevard, Denver, CO 80205, United States; Museum für Naturkunde, Leibniz Institute, Humboldt University Berlin, Invalidenstrasse 43, D-10115 Berlin, Germany; Center for Lunar Science and Exploration, Universities Space Research Association-Lunar, Planetary Institute, 3600 Bay Area Boulevard, Houston, TX 77058-1113, United States; Department of Geological Sciences, University of Missouri, Columbia, MO 65211, United States; Planetary Exploration Research Center, Chiba Institute of Technology, 2-17-1 Tsudanuma, Narashino, Chiba 275-0016, Japan; Earth and Atmospheric Sciences, Purdue University, 550 Stadium Mall Drive, West Lafayette, IN 47907-2051, United States; Osservatorio Geologico di Coldigioco, 62021 Apiro (MC), Italy; Department of Civil Engineering and Geological Sciences, 156 Fitzpatrick Hall, University of Notre Dame, Notre Dame, IN 46556, United States; SIO Geological Collections, 301 Vaughan Hall, Scripps Institution of Oceanography, San Diego, CA 92093-0244, United States; Planetary Science Institute, 1700 East Fort Lowell Road, Tucson, AZ 85719, United States; Department of Geology and Geophysics, School of Ocean and Earth Science and Technology, University of Hawaii, Manoa, Honolulu, HI 96822, United States; Unidad de Ciendas Del Agua, Centro de Investigación Científica de Yucatán, A. C., Calle 8, No. 39, Mz. 29, S.M. 64, Cancún, Quintana Roo, 77500, Mexico; Laboratoire des Sciences du Climat et de l'Environnement, Institut Pierre et Simon Laplace, Université de Versailles Saint Quentin en Yveunes-UMR 1572, Avenue de la Terrasse, F-91198 Gif-surYvette Cedex, France; Bruker Nano GmbH, Schwarzschildstraße 12, D-12489 Berlin, Germany; Department of Earth and Environmental Sciences, K.U.Leuven, Box 2408, Celestijnenlaan 200E, 3001 Leuven, Belgium; Natural Resources Canada, Geological Survey of Canada Calgary, 3303 33rd Street NW, Calgary, AB T2L 2A7, Canada; Laboratorio de Paleomagnetismo y Paleoambientes, Programa Universitario de Perforadones en Oceanos y Continentes, Universidad Nadonal Autónoma de México (UNAM), DF 04510 Mexico, Mexico; Department of Earth and Ecosystem Sciences, Lund University, Sölvegatan 12, 223 62 Lund, Sweden; Department of Geology and Geophysics, University of Alaska, Fairbanks, AK 99775, United States 5970 https://www.scopus.com/inward/record.uri?eid=2-s2.0-77749279680&doi=10.1126%2fscience.1177265&partnerID=40&md5=d4ef063d50386d2b1859b4da5242d3a9 cited By 947 P. Schulte L. Alegret I. Arenillas J.A. Arz P.J. Barton P.R. Bown T.J. Bralower G.L. Christeson P. Claeys C.S. Cockell G.S. Collins A. Deutsch T.J. Goldin K. Goto J.M. Grajales-Nishimura R.A.F. Grieve S.P.S. Gulick K.R. Johnson W. Kiessling C. Koeberl D.A. Kring K.G. MacLeod T. Matsui J. Melosh A. Montanari J.V. Morgan C.R. Neal D.J. Nichols R.D. Norris E. Pierazzo G. Ravizza M. Rebolledo-Vieyra W.U. Reimold E. Robin T. Salge R.P. Speijer A.R. Sweet J. Urrutia-Fucugauchi V. Vajda M.T. Whalen P.S. Willumsen article Trajanovski20103387 Ancient Lake Ohrid on the Balkan Peninsula is considered to be the oldest ancient lake in Europe with a suggested Plio-/Pleistocene age. Its exact geological age, however, remains unknown. Therefore, molecular clock data of Lake Ohrid biota may serve as an independent constraint of available geological data, and may thus help to refine age estimates. Such evolutionary data may also help unravel potential biotic and abiotic factors that promote speciation events. Here, mitochondrial sequencing data of one of the largest groups of endemic taxa in the Ohrid watershed, the leech genus Dina, is used to test whether it represents an ancient lake species flock, to study the role of potential horizontal and vertical barriers in the watershed for evolutionary events, to estimate the onset of diversification in this group based on molecular clock analyses, and to compare this data with data from other endemic species for providing an approximate time frame for the origin of Lake Ohrid. Based on the criteria speciosity, monophyly and endemicity, it can be concluded that Dina spp. from the Ohrid watershed, indeed, represents an ancient lake species flock. Lineage sorting of its species, however, does not seem to be complete and/or hybridization may occur. Analyses of population structures of Dina spp. in the Ohrid watershed indicate a horizontal zonation of haplotypes from spring and lake populations, corroborating the role of lake-side springs, particularly the southern feeder springs, for evolutionary processes in endemic Ohrid taxa. Vertical differentiation of lake taxa, however, appears to be limited, though differences between populations from the littoral and the profundal are apparent. Molecular clock analyses indicate that the most recent common ancestor of extant species of this flock is approximately 1.99 ± 0.83 million years (Ma) old, whereas the split of the Ohrid Dina flock from a potential sister taxon outside the lake is estimated at 8.30 ± 3.60 Ma. Comparisons with other groups of endemic Ohrid species indicated that in all cases, diversification within the watershed started ≤2 Ma ago. Thus, this estimate may provide information on a minimum age for the origin of Lake Ohrid. Maximum ages are less consistent and generally less reliable. But cautiously, a maximum age of 3 Ma is suggested. Interestingly, this time frame of approximately 2-3 Ma ago for the origin of Lake Ohrid, generated based on genetic data, well fits the time frame most often used in the literature by geologists. © Author(s) 2010. Article 2010 English 17264189 10.5194/bg-7-3387-2010 Biogeosciences 7 3387 – 3402 11 Balkans; Lake Ohrid; Dina; Erpobdellidae; Hirudinea; Hirudinida; biotic factor; endemic species; geological record; hybridization; leech; molecular analysis; paleobiogeography; Pleistocene; Pliocene; population structure; spatial analysis; speciation (biology); watershed https://www.scopus.com/inward/record.uri?eid=2-s2.0-78149243238&doi=10.5194%2fbg-7-3387-2010&partnerID=40&md5=d75d8cf81099c03128bef9d5e038bd82 Cited by: 43; All Open Access, Gold Open Access, Green Open Access S. Trajanovski C. Albrecht K. Schreiber R. Schultheiß T. Stadler M. Benke T. Wilke article Geissman2010128 2010 English 00963941 10.1029/2010eo140006 Eos 91 American Geophysical Union 128 Department of Earth and Planetary Sciences, University of New Mexico, Albuquerque, United States; Lamont-Doherty Earth Observatory of Columbia University, Palisades, NY, United States; Department of Earth and Planetary Sciences, Rutgers University, Piscataway, NJ, United States; Lamont-Doherty Earth Observatory of Columbia University, United States 14 conference proceeding; plateau; site selection, Colorado; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-77954578562&doi=10.1029%2f2010eo140006&partnerID=40&md5=620142916591c2aaeb7930b2ba21e24a cited By 0 J.W. Geissman P.E. Olsen D.V. Kent article Sulpizio20103273 Four cores from Balkans lakes Ohrid and Prespa were examined for recognition of tephra layers and cryptotephras, and the results presented along with the review of data from other two already published cores from Lake Ohrid. The six cores provide a previously unrealised tephrostratigraphic framework of the two lakes, and provide a new tephrostratigraphic profile (composite) for the Balkans, which spans from the end of the Middle Pleistocene to the AD 472. A total of 12 tephra layers and cryptotephras were recognised in the cores. One is of Middle Pleistocene age (131 ka) and correlated to the marine tephra layer P-11 from Pantelleria Island. Eight volcanic layers are Upper Pleistocene in age, and encompass the period between ca. 107 ka and ca. 31 ka. This interval contains some of the main regional volcanic markers of the central Mediterranean area, including X-6, X-5, Y-5 and Y-3 tephra layers. The other layers of this interval have been related to the marine tephra layers C20, Y-6 and C10, while one was for the first time recognised in distal areas and correlated to the Taurano eruption of probable Vesuvian origin. Three cryptotephras were of Holocene age. Two of which have been correlated to Mercato and AD 472 eruptions of Somma-Vesuvius, while the third has been correlated to the FL eruption from Mount Etna. These recognitions provide a link of the Ohrid and Prespa lacustrine successions to other archives of the central Mediterranean area, like south Adriatic, Ionian, and south Tyrrhenian seas, lakes of southern Italy (Lago Grande di Monticchio, Pantano di San Gregorio Magno and Lago di Pergusa) and Balkans (Lake Shkodra). © 2010 Author(s). Article 2010 English 17264189 10.5194/bg-7-3273-2010 Biogeosciences 7 3273 – 3288 10 Italy; Lake Mikri Prespa; Lake Ohrid; Pantelleria; Sicily; Trapani; data set; Holocene; Pleistocene; stratigraphy; succession; tephrochronology; volcanic eruption https://www.scopus.com/inward/record.uri?eid=2-s2.0-77958566354&doi=10.5194%2fbg-7-3273-2010&partnerID=40&md5=4bd4b5cbf0d95a2f3bf5e96178eace6d Cited by: 69; All Open Access, Gold Open Access, Green Open Access R. Sulpizio G. Zanchetta M. D'Orazio H. Vogel B. Wagner article Zhi-qiang201079 Through tectonostratigraphic analysis of the nonmarine, intracontinental Songliao basin in northeast China, four episodes of deformation are recognized: mantle upwelling, rift, postrift thermal subsidence and structural inversion. The episodes are related to regional geodynamics and plate motions. Each episode is associated with a specific stratigraphic signature. The first period of deformation occurred during the Middle and Late Jurassic when asthenospheric upwelling heated, thinned and stretched the lithosphere. These events may have been caused by the narrowing of the Okhotsk Sea through subduction. This deformation is characterized by doming, extension, widespread volcanism and intrusion, and erosion. Volcanics interfinger with alluvial fan and alluvial plain facies systems tracts. The second rifting episode began in the latest Jurassic and continued into the Early Cretaceous. It resulted in the formation of a large number of isolated, NNE-trending fault blocks of 'basin-and-range' style. Rifting may have been caused by the formation and subduction of the Izanagi and Pacific Plates. Coal-bearing fluvial, floodplain, lacustrine and fan-delta strata and widespread volcanic rocks filled the fault-block basins. Volcanic strata hundreds to several thousand meters thick in the Huoshiling and Yingcheng Formations record multiple intrusive events during the rifting stage in the basin. These events were concurrent with episodes of intrusion and volcanic eruption in northeast China. The third phase of regional postrift deformation and subsidence, which began with the Lower Cretaceous Denglouku Formation, was caused by lithospheric cooling and extension, modulated by multiple compressional events. Subsidence in the Songliao basin permitted accumulation of thick postrift deposits, in contrast with other Cretaceous basins in Mongolia and northeast Asia. Three compressional episodes, which episodically interrupted the long-term cooling subsidence, originated from development of the Okhotsk suture and subduction of the Pacific plate. In the Early Cretaceous, pronounced compression originated from closure of Okhotsk Sea, forming the mountain ranges of Daxinganling, which provided sediment to the northern part of the basin. In the Late Cretaceous, the intensity of compression from the Pacific margin increased through time, causing westward migration of depocentres and uplift in the east until the end of Cretaceous. Postrift strata, typically 3000-4000 m thick with a maximum thickness of 6000 m, extend beyond the rift blocks and onlap the basin margins to form a large uniform basin. Early thermal subsidence strata include alluvial fan, fluvial, floodplain, shallow lacustrine and delta facies tracts, overlain by large deltaic and lacustrine facies. Late postrift environments featured by large lakes in the basin centre rimmed by delta, fluvial and floodplain environments. Reflection seismic profiles show that strong structural inversion, including folding and uplift, began at the end of the Nenjiang Formation and culminated at the end of the Cretaceous. The main compressional stress field changed from NW to NWW at the end of the Cretaceous, which caused changes in the direction of folding. During the rifting stage, several sets of gas-bearing reservoirs formed in association with coal-bearing source rocks in fluvial and deltaic strata with reservoir-quality volcanics and fluvial and fan-delta sandstone. Thick, widespread mudstone deposited in deep lakes during the postrift stage contains abundant organic matter, and is an important source rock and regional cap rock. Good reservoirs occur in deltaic and fluvial strata. Because of the episodic compressional events that alternately caused subsidence and uplift, reservoirs are sandwiched between source rocks, providing direct fluid communication from source to reservoir. © 2009 The Authors. Journal Compilation © Blackwell Publishing Ltd, European Association of Geoscientists & Engineers and International Association of Sedimentologists. 2010 English 0950091X 10.1111/j.1365-2117.2009.00445.x Basin Research 22 79-95 PetroChina Daqing Oilfield Company, Daqing City, Helongjiang, China; PetroChina, 9 Dongzhimen North Street, Dongcheng District, Beijing, China; Faculty of Earth Resources, China University of Geosciences, Wuhan City, Hubei, China; Department of Geology and Geological Engineering, Colorado School of Mines, Golden, CO, United States 1 alluvial fan; asthenosphere; Cretaceous; deformation mechanism; depocenter; extension; fan delta; floodplain; geodynamics; hydrocarbon reservoir; Jurassic; lacustrine deposit; lithostratigraphy; plate motion; rifting; sediment thickness; sedimentary sequence; seismic reflection; subduction; subsidence; systems tract; tectonostratigraphy; temperature effect; upwelling; volcanism, China; Pacific Ocean; Sea of Okhotsk; Songliao Basin https://www.scopus.com/inward/record.uri?eid=2-s2.0-74949097734&doi=10.1111%2fj.1365-2117.2009.00445.x&partnerID=40&md5=6835dd365323f7a3f2eee5497d1ed10e cited By 345 F. Zhi-qiang J. Cheng-zao X. Xi-nong Z. Shun F. Zi-hui T.A. Cross article Lambert2010509 The 200 Ma, 24-km-diameter Rochechouart impact structure was formed in granitic intrusive and metamorphic rocks of Variscan age (400-300 Ma) close to the margin of the Mesozoic sea. Fractured basement and autochthonous breccias form a several-decameter-thick semicontinuous zone over an 18-20-km-diameter zone. Impact melt rocks, suevite, and polymict lithic breccia are spread over an ∼15 km inner zone, forming a centro-symmetric deposit inclined 0.6°N. No topographic expression of the central uplift exists. The crater floor is at the same elevation (∼±50 m) over a zone at least 20 km in diameter, corresponding to the central part of the original crater. The pre-erosional diameter of the crater is probably larger than previously thought and possibly reached 40-50 km. The structure appears much less eroded than previously thought, as the sequence of crater fill is complete as exposed near Chassenon. The suevite in Chassenon is capped by an ash-like horizontal deposit of very glass-poor, fine-grained, lithic debris derived from basement rocks. Material with similar grain size and composition is observed in centimeter-to meter-thick multilayered glassbearing intercalations (dikes) cutting through the suevite. The integrity of the Chassenon sequence strikingly contrasts with the age and morphology of the structure, implying that a rapid and thick sedimentary deposit has covered the crater to protect it from erosion. The impactoclastic top deposit also firmly constrains the thickness and volume of the initial crater fill, which appear extremely depleted (by a factor of 5 or more) compared with similar-sized impact structures and model-based calculations. This anomaly remains unexplained. All the impactites, including the glass-poor and glass-free impactites, are characterized by a prominent K-metasomatism signifying pronounced postimpact hydrothermal activity. Exposed in isolated occurrences from the center to the periphery of the inner 15-km-diameter zone, impact melt rocks are extremely unlikely to have formed a continuous sheet. They display a large variety of textures, grading from pure melt rock into basal suevite, which are distinct in composition, texture, and setting from the main suevite body forming the top of the impact deposit. Heterogeneity and relative inefficiency in mixing are characteristic of the whole impact deposit, resulting in heterogeneous melts at the scale of hand specimens, but also at the kilometer scale, as suggested by close ties between the composition of melt-bearing rocks and the subjacent target rocks.. © 2010 The Geological Society of America. All rights reserved. 2010 10.1130/2010.2465(25) Special Paper of the Geological Society of America 465 509-541 Sciences et Applications, Le Lafayette, avenue Kennedy, 33700 Bordeaux-Mérignac, France https://www.scopus.com/inward/record.uri?eid=2-s2.0-78650943083&doi=10.1130%2f2010.2465%2825%29&partnerID=40&md5=be0f14b7ad518b68a1f210d1e099ceff cited By 21 P. Lambert article Wang2010655 On 20 September 1999, the Ms 7.6 Chi-Chi earthquake ruptured the Chelungpu fault in central Taiwan. After the earthquake, several boreholes of different depths were drilled. Those boreholes penetrated the fault plane. The physical (mechanical, thermal, hydraulic, electric, and magnetic) parameters were measured either on the core samples or through well-loggings. Results are significant for studies of the Chelungpu fault. However, the measured results are published in different articles and reports. It is not convenient for the earth scientists to take advantage of those results. Hence, those results are compiled and described in this paper. In addition, the correlations among a few parameters are also reported. 2010 English 10170839 10.3319/TAO.2009.09.01.01(T) Terrestrial, Atmospheric and Oceanic Sciences 21 655-673 Institute of Earth Sciences, Academia Sinica, Taipei 115, Taiwan 4 borehole; Chi-Chi earthquake 1999; earthquake magnitude; fault plane; physical property; rupture; well logging, Taiwan https://www.scopus.com/inward/record.uri?eid=2-s2.0-77956575983&doi=10.3319%2fTAO.2009.09.01.01%28T%29&partnerID=40&md5=b9fc2de6651f7daaa38ac52b008a0429 cited By 4 J.-H. Wang article Dong20101141 We utilize an integrated permeability and porosity measurement system to measure the stress dependent permeability and porosity of Pliocene to Pleistocene sedimentary rocks from a 2000m borehole. Experiments were conducted by first gradually increasing the confining pressure from 3 to 120MPa and then subsequently reducing it back to 3MPa. The permeability of the sandstone remained within a narrow range (10-14-10-13m2). The permeability of the shale was more sensitive to the effective confining pressure (varying by two to three orders of magnitude) than the sandstone, possibly due to the existence of microcracks in the shale. Meanwhile, the sandstone and shale showed a similar sensitivity of porosity to effective pressure, whereby porosity was reduced by about 10-20% when the confining pressure was increased from 3 to 120MPa. The experimental results indicate that the fit of the models to the data points can be improved by using a power law instead of an exponential relationship. To extrapolate the permeability or porosity under larger confining pressure (e.g. 300MPa) using a straight line in a log-log plot might induce unreasonable error, but might be adequate to predict the stress dependent permeability or porosity within the experimental stress range. Part of the permeability and porosity decrease observed during loading is irreversible during unloading. © 2010 Elsevier Ltd. 2010 English 13651609 10.1016/j.ijrmms.2010.06.019 International Journal of Rock Mechanics and Mining Sciences 47 Elsevier BV 1141-1157 Graduate Institute of Applied Geology, National Central University, No. 300, Jungda Road, Jungli, Taoyuan 32001, Taiwan; Department of Earth and Planetary Systems Science, Graduate School of Science, Hiroshima University, Higashi-Hiroshima, Japan; Institute of Geophysics, National Central University, Jungli, Taoyuan, Taiwan; Department of Geosciences, National Taiwan University, Taipei, Taiwan; Department of Geophysics, Stanford University, California, United States 7 Digital storage; Mechanical permeability; Microcracks; Porosity; Road construction; Rock pressure; Sandstone; Unloading, Confining pressures; Effective pressure; Log-log plots; Permeability and porosities; Stress dependence; Stress history; Stress-dependent; Three orders of magnitude, Shale https://www.scopus.com/inward/record.uri?eid=2-s2.0-77956652607&doi=10.1016%2fj.ijrmms.2010.06.019&partnerID=40&md5=e5b4dc8a7b4028d15de6f2c13b360c12 cited By 385 J.-J. Dong J.-Y. Hsu W.-J. Wu T. Shimamoto J.-H. Hung E.-C. Yeh Y.-H. Wu H. Sone book Zang20101 This book about rock stress is suitable for students in geosciences and rock engineering, who need to broaden their horizons about the Stress Field of the Earth?s Crust. The book covers the topic so that geosciences students will be able to grasp the Cauchy Stress Principle without fear of matrix transformations in an exercise. Students interested in mathematics, physics and engineering will learn how strain gauges are used to obtain in-situ stress by the overcoring method. Leading edge technology in determining rock stress like quadruple packer and the Kaiser effect are presented together with classical methods like hydraulic fracturing. Borehole techniques (breakouts) and core-based methods (anelastic strain recovery) are illustrated. With respect to stress data, we choose to present the scientific ultra-deep drilling project KTB (Germany), the excavation for nuclear waste disposal at Olkiluoto (Finland) and the drilling into a seismic active fault zone at SAFOD (USA). Stress compilations viewed by the World Stress Map project are presented and interpreted in terms of plate tectonics. © Springer Science+Business Media B.V. 2010. 2010 English 9781402084430 10.1007/978-1-4020-8444-7 Stress Field of the Earth's Crust Springer Netherlands 1-322 GFZ German Research Centre for Geosciences, Telegrafenberg, 14473 Potsdam, Germany; KTH Stockholm, Sweden https://www.scopus.com/inward/record.uri?eid=2-s2.0-84892356084&doi=10.1007%2f978-1-4020-8444-7&partnerID=40&md5=b1f2cdcfd941a663adbd257bbfbf091c cited By 343 A. Zang O. Stephansson article Lindhorst20103531 Ancient Lake Ohrid is a steep-sided, oligotrophic, karst lake that was tectonically formed most likely within the Pliocene and often referred to as a hotspot of endemic biodiversity. This study aims on tracing significant lake level fluctuations at Lake Ohrid using high-resolution acoustic data in combination with lithological, geochemical, and chronological information from two sediment cores recovered from sub-aquatic terrace levels at ca. 32 and 60 m water depth. According to our data, significant lake level fluctuations with prominent lowstands of ca. 60 and 35 m below the present water level occurred during Marine Isotope Stage (MIS) 6 and MIS 5, respectively. The effect of these lowstands on biodiversity in most coastal parts of the lake is negligible, due to only small changes in lake surface area, coastline, and habitat. In contrast, biodiversity in shallower areas was more severely affected due to disconnection of today sub-lacustrine springs from the main water body. Multichannel seismic data from deeper parts of the lake clearly image several clinoform structures stacked on top of each other. These stacked clinoforms indicate significantly lower lake levels prior to MIS 6 and a stepwise rise of water level with intermittent stillstands since its existence as water-filled body, which might have caused enhanced expansion of endemic species within Lake Ohrid. © Author(s) 2010. Article 2010 English 17264189 10.5194/bg-7-3531-2010 Biogeosciences 7 3531 – 3548 11 Lake Ohrid; acoustic data; biodiversity; chronology; coastal zone; endemic species; geochemical method; habitat type; karst; lacustrine deposit; lithology; oligotrophic environment; paleoenvironment; Pliocene; resolution; sediment core; seismic data; stratigraphy; water depth; water level https://www.scopus.com/inward/record.uri?eid=2-s2.0-78349276994&doi=10.5194%2fbg-7-3531-2010&partnerID=40&md5=6c262ff246a822c66d4e730fd9a92ad4 Cited by: 51; All Open Access, Gold Open Access, Green Open Access K. Lindhorst H. Vogel S. Krastel B. Wagner A. Hilgers A. Zander T. Schwenk M. Wessels G. Daut article Vogel20103333 Lake Ohrid is likely of Pliocene age and thus commonly referred to as the oldest existing lake in Europe. In this study spatial variability of recent sediment composition is assessed using >50 basin wide distributed surface sediment samples. Analysis of biogeochemical bulk parameters, selected metals, pigment concentrations as well as grain size distributions revealed a significant spatial heterogeneity in surface sediment composition. It implies that sedimentation in Lake Ohrid is controlled by an interaction of multiple natural and anthropogenic factors and processes. Major factors controlling surface sediment composition are related to differences in geological catchment characteristics, anthropogenic land use, and a counterclockwise rotating surface water current. In some instances processes controlling sediment composition also seem to impact distribution patterns of biodiversity, which suggests a common interaction of processes responsible for both patterns. Article 2010 English 17264189 10.5194/bg-7-3333-2010 Biogeosciences 7 3333 – 3342 10 Lake Ohrid; anthropogenic source; assessment method; biodiversity; biogeochemistry; catchment; chemical composition; concentration (composition); grain size; heterogeneity; lacustrine deposit; land use; metal; pigment; Pliocene; sedimentation; spatial variation; surficial sediment https://www.scopus.com/inward/record.uri?eid=2-s2.0-78049525261&doi=10.5194%2fbg-7-3333-2010&partnerID=40&md5=f4561f3cad8fa7ca30d42ed04d40bf1c Cited by: 61; All Open Access, Gold Open Access, Green Open Access H. Vogel M. Wessels C. Albrecht H.-B. Stich B. Wagner article Xu2010621 We investigated the spatiotemporal distribution of 137Cs radioactivity in surface sediment of Qinghai Lake, and developed the spatial pattern of sedimentation rate. The 137Cs inventory is higher near the estuary/bank area, but lower at the central lake. On the other hand, the average 137Cs activity is lower near the estuary/bank area, but higher at the central lake. The mass accumulation rate (MAR) and the fluxes and contents of the terrestrial detritus (e.g. SiO2, Fe2O3, and Ti) are higher near the estuary/bank area, but lower at the central lake. The chemical/biogenic deposits (e.g. the autogenic carbonates) take up higher fractions at the central lake. These suggest that the spatial pattern of recent sedimentation rate is dominated by the deposition of terrestrial detritus. The average MAR (0.0337g cm-2a-1) was estimated based on those of different cores of Qinghai Lake and was verified by a Ca mass-balance method. The fluxes of total lake sediments, terrestrial detritus, and direct atmospheric deposits were also estimated. © Science China Press and Springer-Verlag Berlin Heidelberg 2009. Article 2010 English 18619541 10.1007/s11434-009-0580-x Chinese Science Bulletin 55 621 – 627 7 https://www.scopus.com/inward/record.uri?eid=2-s2.0-77949303820&doi=10.1007%2fs11434-009-0580-x&partnerID=40&md5=3d2b125e0c9d2926a581215820875e2b Cited by: 46 Hai Xu Xiao Yan Liu Zhi Sheng An Zhao Hua Hou Ji Bao Dong Bin Liu article Xu2010 The Rb/Sr ratios of lake sediments have been suggested as indicators of weathering intensity by increasing work. However, the geochemistry of Rb/Sr ratios of lake sediments is variable between different lakes. In this study, we investigated the spatial and temporal patterns of Rb/Sr ratios, as well as those of other major elements in surface sediments of Lake Qinghai. We find that the spatial pattern of Rb/Sr ratios of the bulk sediments correlates well with that of the mass accumulation rate, and those of the terrigenous fractions, e.g., SiO2, Ti, and Fe. The temporal variations of Rb/Sr ratios also synchronize with those of SiO2, Ti, and Fe of each individual core. These suggest that Rb/Sr ratios of the surface sediments are closely related to terrigenous input from the catchment. Two out of eight cores show similar trends between Rb/Sr ratios and precipitation indices on decadal scales; however, the other cores do not show such relationship. The result of this study suggests that physical weathering and chemical weathering in Lake Qinghai catchment have opposite influence on Rb/Sr ratios of the bulk sediments, and they compete in dominating the Rb/Sr ratios of lake sediments on different spatial and temporal scales. Therefore, it is necessary to study the geochemistry of Rb/Sr ratio of lake sediments (especially that on short term timescales) particularly before it is used as an indicator of weathering intensity of the catchment. © 2010 Xu et al; licensee BioMed Central Ltd. Article 2010 English 14674866 10.1186/1467-4866-11-3 Geochemical Transactions 11 China; Qinghai; Qinghai Lake; accumulation rate; catchment; lacustrine deposit; rubidium; sediment chemistry; spatial variation; strontium; surficial sediment; temporal variation; terrigenous deposit; weathering https://www.scopus.com/inward/record.uri?eid=2-s2.0-77954326037&doi=10.1186%2f1467-4866-11-3&partnerID=40&md5=eb1fbf6ed480ef6212c7ea1ef7f400b0 Cited by: 66; All Open Access, Gold Open Access, Green Open Access Hai Xu Bin Liu Feng Wu article Kastner2010887 We studied the internal lake processes that control the spatial distribution and characteristics of modern sediments at the ICDP (International Continental Scientific Drilling Program) deep drilling site in Laguna Potrok Aike, southern Patagonia, Argentina. Sediment distribution patterns were investigated using a dense grid of 63 gravity cores taken throughout the lake basin and 40 additional shoreline samples. Analysis of the surficial sediment distribution points to distinct internal depositional dynamics induced by wind-driven lake internal currents. Distribution maps illustrate that the spatial characteristics of analysed variables are linked to high erosional wave activity. Persistent wave action and littoral erosion along all shores, especially the eastern shore, is caused by prevailing Southern Hemispheric Westerlies. Several sediment variables (grain size, benthic diatoms, total inorganic carbon and calcium) indicate re-suspension of littoral sediment followed by re-distribution to profundal accumulation areas near the eastern shore. Variations within the catchment influence sediment characteristics in the north-eastern bay. That area is characterized by different mineralogical and sedimentological conditions as well as greater accumulation of pollen, inorganic carbon and diatoms. These findings are related to the influence of episodic inflow into this bay. Spatial differences in stable isotope values throughout the lake suggest that ephemeral tributaries around the lake basin may also contribute to the detected spatial sediment variations. © 2010 Springer Science+Business Media B.V. Article 2010 10.1007/s10933-010-9462-0 Journal of Paleolimnology 44 887 – 902 4 Argentina; Laguna Potrok Aike; Patagonia; Santa Cruz [Argentina]; Bacillariophyta; bioaccumulation; calcium; catchment; deep drilling; diatom; grain size; gravity; inorganic carbon; intertidal environment; lacustrine deposit; microfossil; mineralogy; pollen; sediment; sediment chemistry; sedimentology; shoreline; Southern Hemisphere; spatial distribution; stable isotope; surficial sediment; wave action https://www.scopus.com/inward/record.uri?eid=2-s2.0-78049269851&doi=10.1007%2fs10933-010-9462-0&partnerID=40&md5=863cf294df8d52bb4a1c18986975a3d7 Cited by: 27 Stephanie Kastner Christian Ohlendorf Torsten Haberzettl Andreas Lücke Christoph Mayr Nora I. Maidana Frank Schäbitz Bernd Zolitschka article Jin20101536 River waters play a significant role in supplying naturally- and anthropogenically-derived materials to Lake Qinghai, northeastern Tibetan Plateau. To define the sources and controlling processes for river water chemistry within the Lake Qinghai catchment, high precision ICP-MS trace element concentrations were measured in water samples collected from the Buha River weekly in 2007, and from other major rivers in the post-monsoon (late October 2006) and monsoon (late July 2007) seasons. The distributions of trace elements vary in time and space with distinct seasonal patterns. The primary flux in the Buha River is higher TDS and dissolved Al, B, Cr, Li, Mo, Rb, Sr and U during springtime than those during other seasons and is attributed to the inputs derived from both rock weathering and atmospheric processes. Among these elements, the fluxes of dissolved Cr, B and Rb are strongly influenced by eolian dust input. The fluxes of dissolved Li, Mo, Sr and U are also influenced by weathering processes, reflecting the sensitivity of chemical weathering to monsoon conditions. The anthropogenic sources appear to be the dominant contribution to potentially harmful metals (Ni, Cu, Co, Zn and Pb), with high fluxes at onset of the main discharge pulses due, at least partially, to a runoff washout effect. For other major rivers, except for Ba, concentrations of trace elements are higher in the monsoon than in the post-monsoon season. A total of 38.5 ± 3.1 tons of potentially harmful elements are transported into the lake annually, despite human activities within the catchment being limited. Nearly all river water samples contain dissolved trace elements below the World Health Organization guidelines for drinking water, with the exception of As and B in the Daotang River water samples collected in late July probably mobilized from underlying lacustrine sediments. © 2010 Elsevier Ltd. Article 2010 English 08832927 10.1016/j.apgeochem.2010.08.004 Applied Geochemistry 25 1536 – 1546 10 Buha River; China; Qinghai; Qinghai Lake; Agricultural chemicals; Atmospheric thermodynamics; Barium; Catchments; Chromium; Copper; Dissolution; Inductively coupled plasma mass spectrometry; Lakes; Lead; Molybdenum; Potable water; Rivers; Rubidium; Runoff; Sediments; Soil mechanics; Weathering; Zinc; Anthropogenic sources; Atmospheric process; Chemical weathering; Controlling process; Derived materials; Discharge pulse; Dominant contributions; Drinking water; Eolian dust; High flux; High precision; Human activities; Lacustrine sediments; Monsoon conditions; Post-monsoon; River water; River water samples; Rock weathering; Seasonal patterns; Tibetan Plateau; Time and space; Trace element concentrations; Water samples; Weathering process; World Health Organization; aluminum; anthropogenic source; catchment; chemical weathering; chromium; discharge; drinking water; human activity; lacustrine deposit; monsoon; plateau; pollutant source; river water; water chemistry; World Health Organization; zinc; Trace elements https://www.scopus.com/inward/record.uri?eid=2-s2.0-77957021510&doi=10.1016%2fj.apgeochem.2010.08.004&partnerID=40&md5=d876d53a77bca43f3ad0ebaf9ed2f94e Cited by: 33 Zhangdong Jin Chen-Feng You Tsai-Luen Yu Bo-Shian Wang article Hergert2010132 The slip rate along a fault controls the accumulation of strain that is eventually released during an earthquake. Along a 150-km-long stretch of the North Anatolian fault near Istanbul, Turkey, strain has been building up 2 since the last large earthquake in 1766. Estimates of the geodetic slip rates along the main Marmara fault vary widely, ranging between 17 and 27.9 mm yr-1 (refs 2-5). This slip rate is difficult to quantify because of the lack of satellite observations offshore and the complexity of the submarine fault system that includes the main Marmara fault2,6,7. Here we estimate the right-lateral slip rate on the main Marmara fault using a three-dimensional geomechanical model that incorporates these structural complexities. From our simulations we infer slip rates between 12.8 and 17.8 mm yr-1; our estimates are smaller and more variable than previous results, primarily because of slip partitioning and internal deformation. Our model results reconcile geodetic observations and geological fault slip rates8-10, which had been considered conflicting previously. We suggest that the inferred variability in slip rate on the main Marmara fault favours segmented release of seismic moment during consecutive events over the failure of the whole seismic gap in one large earthquake. © 2010 Macmillan Publishers Limited. All rights reserved. 2010 English 17520894 10.1038/ngeo739 Nature Geoscience 3 132-135 Geophysical Institute, Universität Karlsruhe (TH), Hertzstr. 16, 76187 Karlsruhe, Germany; GFZ German Research Centre for Geosciences, Telegrafenberg, 14773, Potsdam, Germany 2 accumulation rate; analytical method; earthquake; fault displacement; satellite imagery; slip rate; three-dimensional modeling, Sea of Marmara; Turkey https://www.scopus.com/inward/record.uri?eid=2-s2.0-76449107435&doi=10.1038%2fngeo739&partnerID=40&md5=a528688a3102d705fbe4fff469519d1c cited By 72 T. Hergert O. Heidbach article gu2010mudstone 2010 China Mining Magazine 19 161-165 J Gu YJ Huang C Wang article Schleicher2010667 Mudrock samples were investigated from two fault zones at ~3066 m and ~3296 m measured depth (MD) located outside and within the main damage zone of the San Andreas Fault Observatory at Depth (SAFOD) drillhole at Parkfield, California. All studied fault rocks show features typical of those reported across creep zones with variably spaced and interconnected networks of polished displacement surfaces coated by abundant polished films and occasional striations. Electron microscopy and X-ray diffraction study of the surfaces reveal the occurrence of neocrystallized thin film clay coatings containing illite-smectite (I-S) and chlorite-smectite (C-S) minerals. 40Ar/39Ar dating of the illitic mix-layered coatings demonstrated Miocene to Pliocene crystallization and revealed an older fault strand (8 ± 1.3 Ma) at 3066 m MD, and a probably younger fault strand (4 ± 4.9 Ma) at 3296 m MD. Today, the younger strand is the site of active creep behavior, reflecting a possible (re)activation of these clay-weakened zones. We propose that the majority of slow fault creep is controlled by the high density of thin (&lt;100 nm thick) nanocoatings on fracture surfaces, which are sufficiently smectite-rich and interconnected at low angles to accommodate slip with minimal breakage of stronger matrix clasts. Displacements occur by frictional slip along particle surfaces and hydrated smectitic phases, in combination with intracrystalline deformation of the clay lattice, associated with extensive mineral dissolution, mass transfer, and residual precipitation of expandable layers. The localized concentration of smectite in both I-S and C-S minerals contributes to fault weakening, with fracturing and fluid infiltration creating new nucleation sites for neomineralization on displacement surfaces during continued faulting. The role of newly grown, ultrathin, hydrous clay coatings contrasts with previously proposed scenarios of reworked talc and/or serpentine phases as an explanation for weak fault and creep behavior at these depths. © 2010 Geological Society of America. 2010 English 00917613 10.1130/G31091.1 Geology 38 667-670 Department of Geological Sciences, University of Michigan, 1100 North University Avenue, Ann Arbor, MI 48109, United States; Ernst-Moritz-Arndt Universität Institut für Geographie und Geologie, F. Ludwig-Jahn-Strasse 17A, D-17487 Greifswald, Germany 7 California; Clay coating; Creep behaviors; Damage zones; Drill hole; Fault creep; Fault rock; Fault strands; Fault zone; Fracture surfaces; Frictional slip; High density; Illite-smectite; Interconnected network; Layered coatings; matrix; Measured depths; Mineral dissolution; Miocene; Nano-coatings; Nucleation sites; Older faults; Particle surface; Pliocene; San Andreas Fault; Smectites; Ultra-thin; X-ray diffraction studies, Coatings; Creep; Dissolution; Hydrates; Minerals; Precipitation (chemical); Serpentine; Silicate minerals; Structural geology; X ray diffraction, Clay minerals, argon isotope; clay mineral; creep; deformation; displacement; fault zone; illite; mudstone; San Andreas Fault; smectite, California; Parkfield; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-77955969539&doi=10.1130%2fG31091.1&partnerID=40&md5=89115cb30c4a8f1230ae9b93e8369226 cited By 123 A.M. Schleicher B.A. Pluijm L.N. Warr article Rentsch2010477 We present the principles of a recently developed event location procedure and its application to seismicity recorded in the main borehole of the San Andreas Fault Observatory at Depth (SAFOD). The basic idea of the location approach is the backpropagation of the recorded wavefield along rays using a Gaussian-beam-type weighting factor. In the case of a sufficient number of receivers, the intersection of these rays results in a distinct maximum at the corresponding hypocentre location. We have applied this technique to data recorded with an 80-level three-component (3C) receiver array in the SAFOD main hole and we have located a number of events in the vicinity of the fault system. A modification of the location algorithm also allowed the precise location of one of the so-called target events, which are the subject of recent drilling activities as well as ongoing research at SAFOD. We summarize the principles of the location method and the performed processing steps, provide estimates of the uncertainties for the target event location and test the robustness of the location using six different 3-D velocity models. Furthermore, we discuss the event locations in comparison with borehole logging data and coincident seismic reflection images and we also show identified events with highly correlated waveforms. © 2010 The Authors Journal compilation © 2010 RAS. 2010 English 0956540X 10.1111/j.1365-246X.2010.04638.x Geophysical Journal International 182 477-492 Freie Universität Berlin, FR Geophysik, Malteserstr, 74-100, 12249, Berlin, Germany 1 back propagation; body wave; borehole; San Andreas Fault; seismic migration; seismic reflection; seismicity; seismotectonics; spatial analysis; time series analysis; wave propagation https://www.scopus.com/inward/record.uri?eid=2-s2.0-77954641667&doi=10.1111%2fj.1365-246X.2010.04638.x&partnerID=40&md5=931435e8110016ab1f8838d6604ee1a7 cited By 8 S. Rentsch S. Buske S. Gutjahr J. Kummerow S.A. Shapiro article Janssen2010 Several types of amorphous material in ultracataclastic core samples recovered from 3194 m and 3294 m depth of the main bore hole of the San Andreas Fault Observatory at Depth are identified and described with transmission electron microscopy and scanning electron microscopy. We observed (1) amorphous material on a slickenside surface, (2) glassy bands contained in an ultracataclastic matrix and (3) amorphous rims surrounding quartz or feldspar clasts. Chemical analyses of the amorphous material reveal that silica content is slightly enriched or similar as in the adjacent matrix. We suggest that all amorphous material was formed by comminution of clasts (crush-origin pseudotachylytes) rather than by melting (melt-origin pseudotachylytes). The observed amorphous phases may act as lubricating layers that reduce friction in the San Andreas Fault. Copyright 2010 by the American Geophysical Union. 2010 English 00948276 10.1029/2009GL040993 Geophysical Research Letters 37 Department of Geodynamics and Geomaterials, GFZ German Research Centre for Geosciences, D-14473 Potsdam, Germany; Department of Chemistry and Material Cycles, GFZ German Research Centre for Geosciences, D-14473 Potsdam, Germany; Department of Earth and Planetary Science, University of California, Berkeley, CA 94720-4767, United States 1 Adjacent matrix; Amorphous phasis; matrix; Pseudotachylytes; San Andreas Fault; Silica content, Core samples; Grinding (comminution); Oxide minerals; Quartz; Scanning electron microscopy; Silica; Silicate minerals; Transmission electron microscopy, Amorphous materials, amorphous medium; borehole; chemical analysis; clast; feldspar; melting; San Andreas Fault; silica; slickenside; transmission electron microscopy https://www.scopus.com/inward/record.uri?eid=2-s2.0-75749134827&doi=10.1029%2f2009GL040993&partnerID=40&md5=3f8124d1a90c03153df9830d8d8cf58c cited By 53 C. Janssen R. Wirth E. Rybacki R. Naumann H. Kemnitz H.-R. Wenk G. Dresen article Powers2010 The distribution of seismicity about strike-slip faults provides measurements of fault roughness and damage zone width. In California, seismicity decays with distance from strike-slip faults according to a power law -(1 + ×2/d2)-g/2. This scaling relation holds out to a fault-normal distance × of 3?6 km and is compatible with a ?rough fault loading? model in which the inner scale d measures the half width of a volumetric damage zone and the roll-off rate g is governed by stress variations due to fault roughness. According to Dieterich and Smith?s 2-D simulations, g approximates the fractal dimension of alongstrike roughness. Near-fault seismicity is more localized on faults in northern California (NoCal, d = 60 ± 20 m, g = 1.65 ± .05) than in southern California (SoCal, d = 220 ± 40 m, g = 1.16 ± .05). The Parkfield region has a damage zone half width (d = 120 ± 30 m) consistent with the SAFOD drilling estimate; its high roll-off rate (g = 2.30 ± .25) indicates a relatively flat roughness spectrum: k-1 versus k-2 for NoCal, k-3 for SoCal. Our damage zone widths (the first direct estimates averaged over the seismogenic layer) can be interpreted in terms of an across-strike ?fault core multiplicity? that is 1 in NoCal, 2 at Parkfield, and 3 in SoCal. The localization of seismicity near individual faults correlates with cumulative offset, seismic productivity, and aseismic slip, consistent with a model in which faults originate as branched networks with broad, multicore damage zones and evolve toward more localized, lineated features with low fault core multiplicity, thinner damage zones, and less seismic coupling. Our results suggest how earthquake triggering statistics might be modified by the presence of faults. Copyright 2010 by the American Geophysical Union. 2010 English 21699313 10.1029/2008JB006234 Journal of Geophysical Research: Solid Earth 115 Blackwell Publishing Ltd Department of Earth Sciences, University of Southern California, ZHS-117, 3651 Trousdale Pkwy, Los Angeles, CA 90089-0742, United States; Southern California Earthquake Center, University of Southern California, ZHS-169, 3651 Trousdale Pkwy., Los Angeles, CA 90089-0742, United States 5 earthquake trigger; normal fault; roughness; seismicity; strike-slip fault; earthquake damage; power law, California; United States; Parkfield https://www.scopus.com/inward/record.uri?eid=2-s2.0-77952280585&doi=10.1029%2f2008JB006234&partnerID=40&md5=8ae84be6c134fc04378638997c869e2d cited By 69 P.M. Powers T.H. Jordan article Li2010880 In order to interpret the climate-change data using the ecological characteristics of the ostracods from the drill cores in Lake Qinghai, the distribution of Recent ostracods was studied in Lake Qinghai area. A total of 34 species belonging to the Ostracoda class of Crustacea were collected from different bodies of water in the Lake Qinghai area, and the ecological information for Recent ostracod species was studied. Among these 34 species, Cypris pubera, Eucypris dulcifons, Ilyocypris sp. 1, Ilyocypris sp. 2, Fabaeformiscandona caudata, Fabaeformiscandona hyalina, Herpetocypris reptans, Prionocypris gansenensis, Potamocypris villosa, Potamocypris smaragdina, Paralimnocythere compressa and Subulacypris sp. were first reported by us in the Lake Qinghai area. Some of the species identified exhibited cosmopolitan distributions, at least in the Holarctic region, but P. gansenensis and Ilyocypris echinata appeared to be restricted to the cold regions in northwestern China. The ecological significance of the primary ostracod species in the Lake Qinghai area was described according to the observations made during our time in the field and according to data from a number of reports. Our results indicate that the species diversity and abundance of ostracods may be related to water salinity in the Lake Qinghai area. The ecological information for ostracods can be used to distinguish different water environments and types based on the characteristics of one species or of an assemblage of several species. © 2010 Elsevier Ltd. All rights reserved. Article 2010 English 1470160X 10.1016/j.ecolind.2010.01.012 Ecological Indicators 10 880 – 890 4 China; Qinghai; Qinghai Lake; Caudata; Crustacea; Eucypris; Eurycypris pubera; Fabaeformiscandona; Herpetocypris reptans; Ilyocypris; Ostracoda; Paralimnocythere; Potamocypris smaragdina; Potamocypris villosa; Prionocypris; Animals; Climate change; Core drilling; Ecology; Salinity measurement; Stream flow; Associations; Cold regions; Crustacea; Drill core; Ecological characteristics; Ecological information; Northwestern China; Ostracoda; Paleolimnology; Species diversity; Water environments; Water salinity; abundance; climate change; community composition; Holarctic Region; lake water; ostracod; population distribution; salinity; species diversity; Lakes https://www.scopus.com/inward/record.uri?eid=2-s2.0-77949275123&doi=10.1016%2fj.ecolind.2010.01.012&partnerID=40&md5=dc2256de39d6974edbfbdc711d389fa6 Cited by: 58 Xiangzhong Li Weiguo Liu Ling Zhang Zhencheng Sun article Zhang2010295 The in-situ stress computations presented by Haimson et al. (2010) overestimated the maximum horizontal stress in the vicinity of the Chelungpu Fault, Taiwan. Our analyses from extended leak-off tests, drilling-induced tensile fractures, and Anderson's faulting theory show considerable lower values for the maximum horizontal stress. Our results suggest that closer to the ruptured fault, more SH is released, implying a strong earth crest in the shallower section, which is far away from the ruptured fault. However, it would require more detailed and intensive work in order to achieve an accurate interpretation of the in-situ stress in this region. © 2010 Elsevier B.V. 2010 English 00401951 10.1016/j.tecto.2010.04.038 Tectonophysics 492 295-298 Shell Exploration and Production Company, Houston, TX 77079, United States; The University of Oklahoma, Norman, OK 73019, United States 1-4 https://www.scopus.com/inward/record.uri?eid=2-s2.0-78650521863&doi=10.1016%2fj.tecto.2010.04.038&partnerID=40&md5=6f262b57bb991c651a40d87242050cc0 cited By 26 J. Zhang J.-C. Roegiers article Birchwood201018 International efforts and advanced techniques are being used to characterize properties and distributions of gas hydrates, which are crystalline solids that resemble ice. The Minerals Management Service (MMS) of the US Department of the Interior has used seismic data, along with wellbore, geologic, geochemical and paleontological information, to assess large areas of the Gulf of Mexico, where pressure and temperature conditions are suitable for hydrate-stability conditions. The team members acquired and analyzed seismic data, selected drilling locations and conducted a 35-day drilling, coring and logging expedition covering several sites. A new program was initiated in 2002 from the Mallik field to conduct production testing of gas hydrates. The USGS has studied gas hydrate accumulations in the Alaska North Slope and estimates that they contain between 25.2 and 157.8 Tcf of undiscovered recoverable natural gas. 2010 English 09231730 Oilfield Review 22 18-33 US Department of Energy, National Energy Technology Laboratory, Morgantown, WV, United States; US Geological Survey, Denver CO, United States; Lamont-Doherty Earth Observatory, Earth Institute of Columbia University, Palisades, NY, United States; Geological Survey of Canada, Sidney, BC, Canada; Japan Oil, Gas and Metals, National Corporation Chiba City, Chiba, Japan 1 Crystalline solids; Gulf of Mexico; Hydrate accumulations; Minerals management services; Pressure and temperature; Production testing; Seismic datas; Team members; Wellbore, Exploratory geochemistry; Gases; Hydration; Natural gas well drilling; Offshore oil wells; Seismic response; Seismic waves; Software testing; Well drilling, Gas hydrates https://www.scopus.com/inward/record.uri?eid=2-s2.0-79958810900&partnerID=40&md5=8b6da24e8b08b3a19de97c5f873f3013 cited By 44 R. Birchwood J. Dai D. Shelander R. Boswell T. Collett A. Cook S. Dallimore K. Fujii Y. Imasato M. Fukuhara K. Kusaka D. Murray T. Saeki article Skinner201040 The science program of the Iceland Deep Drilling Project (IDDP) requires as much core as possible in the transition zone to supercritical and inside the supercritical zone (>374°C), in the depth interval 2400-4500 m. The spot coring system selected has a 7 1/4″ (184.15 mm) OD at 10 m length and collects a 4″ (101.6 mm) diameter core using an 8 1/2″ (215.9 mm) OD core bit. It incorporates design characteristics, materials, clearances and bearings compatible with operation of the core barrel at temperatures as high as 600°C. Special attention was given to the volume of flushing which could be applied to the core barrel and through the bit while running in and out of the borehole and while coring. In November 2008 a successful spot coring test using the new core barrel was performed at 2800 m depth in the production well RN-17 B at Reykjanes, Iceland, where the formation temperature is 322°C. A 9.3-m hydrothermally altered hyaloclastite breccia was cored with 100% core recovery, in spite of it being highly fractured. A core tube data logger was also designed and placed inside the inner barrel to monitor the effectiveness of cooling. The temperature could be maintained at 100°C while coring, but it reached 170°C for a very short period while tripping in. The effective cooling is attributed to the high flush design and a top drive being employed, which allows circulation while tripping in or out, except for the very short time when a new drill pipe connection is being made. 2010 English 18168957 10.2204/iodp.sd.10.05.2010 Scientific Drilling 40-45 ACS Coring Services, 13 Riccarton Drive, Currie, Edinburgh, EH14 5PN, Scotland, United Kingdom; Rok-Max Drilling Tools Ltd., P.O. Box 87, United Kingdom; Iceland Geosurvey (ISOR), Grensasvegur 9, Reykjavik, IS-108, Iceland; HS Orka hf, Brekkustígur 36, 260 Reykjanesbær, Iceland 10 Core barrel; Core tube data logger; Deep drilling; Design characteristics; Drill pipe connection; Formation temperature; Hydrothermally; Icelands; Inner Barrel; Production wells; Running-in; Science programs; Short periods; Spot coring; Super-critical; Transition zones, Design, Drill pipe https://www.scopus.com/inward/record.uri?eid=2-s2.0-78651588219&doi=10.2204%2fiodp.sd.10.05.2010&partnerID=40&md5=b958630914026fcaa2f7d5d5da78ef5f cited By 3 A.C. Skinner P. Bowers S. Pórhallsson G.Ó. Fridleifsson H. Gudmundsson article Lin2025 Article 2010 Acta Pedologica Sinca 47 1029-1038 06 C. Huang J. Retallack C. Wang article Wang2010121 Drilling core from Chinese Continental Scientific Drilling-SK-I(s) presents four sets of deep lake seismite from the lower part of the second member to the bottom of the third member of Qingshankou Formation. Typical structures of the seismites include step micro-fault, seismic fissure bed, autoclastic brecciated structure, load structure, ball-and-pillow structure (pseudonodule), vibration-induced liquefaction structure, enterolithic structure, liquefaction sand dyke and pseudo-mud crack. All of these synsedimentary-penecontemporaneous soft-sediment deformation and absence of seismo-turbidite indicate that the seismites in Qingshankou Formation are previous soft sediment reconstruction related to earthquake. Seismites of Qingshankou Formation exhibit typical developmental pattern and sedimentary sequence of seismite. This seismic sequence consists of the lower unit of liquefaction deformation corresponding to strong earthquake and the upper unit of plastic deformation corresponding to earthquake attenuation. Mudstone with few altered glass shards and volcanic ash interlayers simultaneously developed in Qingshankou Formation from SK-I(s). Mugearite and volcanic breccia developed in well Jin6 and Jin65 and basalt developed in well Qian124 and Qian 109 during corresponding geological time of volcanic ash in SK-I(s). These four wells containing volcanic rock in Qingshankou Formation distribute along the Sunwu-Shuangliao transcrustal fault, which indicates that tectonic-volcanic activities occurred during Qingshankou period in Songliao Basin and seismites recorded earthquake activities induced by tectonic-volcanic event in deep water. Existence of tectonic-volcanic event in Qingshankou Formation suggests that fault activities and volcano eruptions should be normal phenomena during the sag stage in Songliao Basin. 2010 Chinese 10000569 Acta Petrologica Sinica 26 Science Press 121-129 College of Earth Sciences, Jilin University, Changchun 130061, China 1 Faulting; Geophysics; Liquefaction; Seismology; Tectonics; Volcanoes, Qingshankou formation; Seismic sequence; Seismite; SK-I(s); Songliao basin; Volcanic event, Earthquakes, Coniacian; deep water; deformation; geological time; mudstone; Ocean Drilling Program; sedimentary sequence; seismite; synsedimentary tectonics; turbidite; volcanic ash; volcanic eruption; volcanogenic deposit, China; Songliao Basin, Coniacian https://www.scopus.com/inward/record.uri?eid=2-s2.0-84977992328&partnerID=40&md5=3024311874eaf1ab78d5b121714563e9 cited By 10 G. Wang R. Cheng P. Wang Y. Gao article gee_collisional_2010 The COSC project is focused on the mid Paleozoic Caledonide Orogen in Scandinavia in order to better understand orogenic processes, both in the past and in today's active mountain belts. It relates to two of ICDP's main themes – the fundamental physics of plate tectonics and heat, mass and fluid transfer through Earth's crust, and on improving interpretation of geophysical data used to determine the structure and properties of the Earth's crust. Lateral transport of Caledonian allochthons over distances of several hundreds of kilometers in the Scandes, by a combination of thrusting and ductile extrusion, is comparable to that recognized in the Himalayas. The Caledonides in Scandinavia provide special opportunities for understanding Himalayan-type orogeny and the Himalayan Orogen itself, thanks to the deep level of erosion and the paucity of superimposed post-Paleozoic deformation. The surface geology in combination with the seismic, magnetotelluric, magnetic and gravity data provide control of the geometry of the Caledonian structure, both of the allochthon and the underlying parautochthon-autochthon, and define the locations for drilling. The latter will investigate both the high-grade, ductile Caledonian nappes and the underlying allochthons and basement, with two c. 2.5 km deep boreholes, located near Åre and Järpen in western Jämtland. The two boreholes will also provide unique information about other important aspects of the Scandinavian bedrock, including the heat flow and potential for geothermal energy, mineralization in the Seve nappes and alum shales, the uplift history of the Scandes, the Holocene paleoclimatological changes and the deep biosphere. 2010 1103-5897 10.1080/11035891003759188 GFF 132 29 -- 44 1 http://www.informaworld.com/10.1080/11035891003759188 D. G. Gee C. Juhlin C. Pascal P. Robinson article Prokopenko201031 A synthesis of paleoclimate responses from Lake Baikal during the MIS 11 interglacial is presented based on proxy records from two drill sites 245 km apart. BDP-99 is located in vicinity of the delta of the major Baikal tributary, whereas the BDP-96 site represents hemipelagic setting distant from riverine influence. The comparison of thicknesses of interglacial intervals in these contrasting depositional settings confirms the extended ca. 33-kyr duration of the MIS 11 interglacial. The new BDP-99 diatom biostratigraphic record matches that of the BDP-96-2 holostratotype and thus allows establishing establishes robust correlation between the records on the same orbitally-tuned timescale. The first detailed MIS 11 palynological record from the BDP-99 drill core indicates the dominance of boreal conifer (taiga) forest vegetation in the Baikal region throughout the MIS 11 interglacial, since at least 424 ka till ca. 396 ka. The interval ca. 420-405 ka stands out as a "conifer optimum" with abundant Abies sibirica, indicative of climate significantly warmer and less continental than today. The closest Baikal analog to this type of vegetation in the history of the current Holocene interglacial is at ca. 9-7 ka. The warm conifer phase lasted for ca. 15 kyr during MIS 11 interrupted by two millennial-scale cooling episodes at ca. 411-410 and 405-404 ka. Reconstructed annual precipitation of 450- 550 mm/yr during the MIS 11 interglacial is by ca. 100mm higher than during the Holocene; regional climate was less continental with warmer mean temperatures both in summer and in winter. © Author(s) 2010. Article 2010 English 18149324 10.5194/cp-6-31-2010 Climate of the Past 6 Copernicus GmbH 31 – 48 1 Lake Baikal; Russian Federation; Siberia; Abies; Abies sibirica; Bacillariophyta; Coniferophyta; biostratigraphy; boreal forest; coniferous tree; correlation; diatom; dominance; interglacial; paleoclimate; palynology; proxy climate record; regional climate; timescale; vegetation history https://www.scopus.com/inward/record.uri?eid=2-s2.0-84860389161&doi=10.5194%2fcp-6-31-2010&partnerID=40&md5=f4749ee229520c3b9cfeb772fd7a797a Cited by: 50; All Open Access, Gold Open Access, Green Open Access A.A. Prokopenko E.V. Bezrukova G.K. Khursevich E.P. Solotchina M.I. Kuzmin P.E. Tarasov article Matter20103755 To date, little is known about the role of spring waters with respect to authigenic carbonate precipitation in a shallow lacustrine setting. Lake Ohrid, located in Southeastern Europe, is a large lake fed to over 50% by karstic springs of which half enter subaquatically and influence significantly its ecology and species distribution. In order to evaluate how sedimentological processes are influenced by such shallow-water springs, the Kališta subaquatic spring area in the north west of Lake Ohrid was investigated by a sidescan sonar survey and with sediment traps and three transects of gravity short cores. Results indicate that sedimentation in the spring area is dominated by authigenic carbonate precipitation. High sedimentation rates and evidences for bio-induced precipitation processes were observed in the water column and in the sediments. Two distinct stratigraphic units characterize the shallow subsurface, both composed of carbonate silts with high carbonate contents of up to 96%, but differing in color, carbonate content and diatom content. A chronological correlation of the cores by radiocarbon dates and 137Cs activities places the transition between the two stratigraphic units after ∼1955 AD. At that time, coastal sedimentation changed drastically to significantly darker sediments with higher contents of organic matter and more abundant diatoms. This change coincides with the recent human impact of littoral eutrophication. © 2010 Author(s). Article 2010 English 17264189 10.5194/bg-7-3755-2010 Biogeosciences 7 3755 – 3767 11 Lake Ohrid; Bacillariophyta; carbonate; chronology; diatom; eutrophication; lacustrine deposit; littoral environment; precipitation (chemistry); radiocarbon dating; sediment core; sediment trap; sedimentation; silt; sonar; stratigraphy; water column https://www.scopus.com/inward/record.uri?eid=2-s2.0-78649527716&doi=10.5194%2fbg-7-3755-2010&partnerID=40&md5=fa5c4f1e6e6cfede2f7d49d13d4ccc09 Cited by: 30; All Open Access, Gold Open Access, Green Open Access M. Matter F.S. Anselmetti B. Jordanoska B. Wagner M. Wessels A. Wüest article mundil2010calibration 2010 Geochimica et Cosmochimica Acta 74 PERGAMON-ELSEVIER SCIENCE LTD THE BOULEVARD, LANGFORD LANE, KIDLINGTON~… A738--A738 12 Roland Mundil Randall B Irmis Paul E Olsen Dennis V Kent article Huang2010242 The Late Jurassic Kimmeridge Clay Formation (KCF) is an economically important, organic-rich source rock of Kimmeridgian-Early Tithonian age. The main rock types of the KCF in Dorset, UK, include grey to black laminated shale, marl, coccolithic limestone, and dolostone, which occur with an obvious cyclicity at astronomical timescales. In this study, we examine two high-resolution borehole records (Swanworth Quarry 1 and Metherhills 1) obtained as part of a Rapid Global Geological Events (RGGE) sediment drilling project. Datasets examined were total organic carbon (TOC), and borehole wall microconductivity by Formation Microscanner (FMS). Our intent is to assess the rhythmicity of the KCF with respect to the astronomical timescale, and to discuss the results with respect to other key Late Jurassic geological processes. Power spectra of the untuned data reveal a hierarchy of cycles throughout the KCF with ∼ 167 m, ∼ 40 m, 9.1 m, 3.8 m and 1.6 m wavelengths. Tuning the ∼ 40 m cycles to the 405-kyr eccentricity cycle shows the presence of all the astronomical parameters: eccentricity, obliquity, and precession index. In particular, ∼ 100-kyr and 405-kyr eccentricity cycles are strongly expressed in both records. The 405-kyr eccentricity cycle corresponds to relative sea-level changes inferred from sequence stratigraphy. Intervals with elevated TOC are associated with strong obliquity forcing. The 405-kyr-tuned duration of the lower KCF (Kimmeridgian Stage) is 3.47 Myr, and the upper KCF (early part of the Tithonian Stage, elegans to fittoni ammonite zones) is 3.32 Myr. Two other chronologies test the consistency of this age model by tuning ∼ 8-10 m cycles to 100-kyr (short eccentricity), and ∼ 3-5 m cycles to 36-kyr (Jurassic obliquity). The 'obliquity-tuned' chronology resolves an accumulation history for the KCF with a variation that strongly resembles that of Earth's orbital eccentricity predicted for 147.2 Ma to 153.8 Ma. There is evidence for significant non-deposition (up to 1 million years) in the lowermost KCF (baylei-mutabilis zones), which would indicate a Kimmeridgian/Oxfordian boundary age of 154.8 Ma. This absolute calibration allows assignment of precise numerical ages to zonal boundaries, sequence surfaces, and polarity chrons of the lower M-sequence. © 2009 Elsevier B.V. All rights reserved. Article 2010 English 0012821X 10.1016/j.epsl.2009.11.013 Earth and Planetary Science Letters 289 242 – 255 1-2 Dorset [England]; England; United Kingdom; Ammonoidea; Astrophysics; Boreholes; Clay minerals; Offshore oil wells; Organic carbon; Tuning; Absolute calibration; Accumulation history; Borehole records; Borehole wall; Cyclicity; Cyclostratigraphy; Data sets; Dolostones; Drilling projects; Earth systems; Eccentricity cycle; Elegans; England; Geological process; High resolution; Jurassic; Kimmeridge clay formation; M sequence; Microscanner; Orbital eccentricity; Organic-rich source rock; Power-spectra; Relative sea level; Rock types; Seafloor spreading; Sequence stratigraphy; Time-scales; Total organic carbon; accumulation; astrophysics; coccolith; cyclostratigraphy; data set; dolostone; drilling; eccentricity; geochronology; Jurassic; Kimmeridgian; lamination; limestone; marl; Oxfordian; parameterization; sea level change; seafloor spreading; sequence stratigraphy; shale; source rock; timescale; Tithonian; total organic carbon; wavelength; Stratigraphy https://www.scopus.com/inward/record.uri?eid=2-s2.0-72949102215&doi=10.1016%2fj.epsl.2009.11.013&partnerID=40&md5=c0853e365811c689006a2051265be828 Cited by: 64 Chunju Huang Stephen P. Hesselbo conference Kurihara20102908 The methane hydrate (MH) production tests were conducted using the depressurization method in the JOGMEC/NRCan/Aurora Mallik production program in April 2007 and in March 2008. In addition to attaining the first and the only successful methane gas production to the surface from a MH reservoir by depressurization in the world, various data such as wellhead/bottomhole pressure, temperature, gas and water flow rates and the temperature along the casing measured by Distributed Temperature Sensing (DTS) systems were acquired during these tests. The flow rates of gas and water from the reservoir sand face were then estimated by the comprehensive analysis of these data. This paper clarifies the details of the estimation of gas and water flow rates based on these data, for the first time after the 2008 winter test. In 2007, a certain amount of gas and water were produced from a 12 m perforation interval in one of the major MH reservoirs at the Mallik site in Canada, by reducing the bottomhole pressure down to about 7 MPa. However, because of the irregular (on-off) pumping operations due probably to the excessive sand production, the produced gas was not directly delivered to the surface via the tubing, but was accumulated at the top of the casing. Hence, the gas production rate was calculated based on the continuously monitored bottomhole and casing head pressure. Since the produced water was injected into the aquifer located below the MH reservoir, it was impossible to directly measure the water pumping rate. The pumping rate and water production rates were accurately estimated by matching the bottomhole temperature through the numerical simulation using a wellbore model. In 2008, much larger and longer gas production was accomplished with a stepwise reduction of the bottomhole pressure down to about 4.5 MPa, preventing sands from flowing into the wellbore by the screen. In this test, both the gas and water were delivered to the surface, which enables the estimation of the gas and water flow rates from the reservoir sand face as well as liquid level in casing based on the monitored parameters. Investigating the production performances thus estimated, it was inferred what really happened in the reservoir during the tests. These insights must be beneficial for future exploration and development planning for MH resources. Copyright 2010, Society of Petroleum Engineers. 2010 English 9781617388866 10.2523/132155-ms Society of Petroleum Engineers - International Oil and Gas Conference and Exhibition in China 2010, IOGCEC 4 Society of Petroleum Engineers 2908-2931 Japan Oil Engineering Co., Ltd., Japan; Japan Oil, Gas and Metals National Corporation, Japan; Japan Petroleum Exploration Co., Ltd., Japan; National Institute of Advanced Industrial Science and Technology, Japan; University of Tokyo, Japan; Natural Resources Canada, Canada Aquifers; Boreholes; Bottom hole pressure; Flow of water; Flow rate; Gases; Hydration; Hydraulics; Methane; Oil field equipment; Oil wells; Petroleum prospecting; Pumps; Sand; Software testing; Surface testing; Wellheads, Bottom-hole temperatures; Comprehensive analysis; Depressurization methods; Distributed temperature sensing systems; Exploration and development; Gas-hydrate production; Production performance; Water production rate, Gas hydrates https://www.scopus.com/inward/record.uri?eid=2-s2.0-78650623888&doi=10.2523%2f132155-ms&partnerID=40&md5=641a46c909155f92a47d6e6fbeadfc51 cited By 79 M. Kurihara A. Sato K. Funatsu H. Ouchi K. Yamamoto M. Numasawa T. Ebinuma H. Narita Y. Masuda S.R. Dallimore F. Wright D. Ashford article Ortiz-Alemán2010127 The analytic signal method and forward modeling in three dimensions are applied to magnetic field data over the Chicxulub crater in order to determine and document the main magnetic anomaly sources and crater structure in the central zone. Aeromagnetic data over the structure reveal three strong, well-defined concentric patterns, with a central 40-km diameter zone of high amplitude anomalies. Magnetic anomalies are interpreted to be associated with the melt sheet, upper breccias and central uplift, which present three to four orders of magnitude contrasts with the surrounding carbonate units. The limited number of magnetic property measurements, apparent wide range in the remanent intensity and susceptibility in the upper breccias and possible yet unconstrained zones of hydrothermal systems have restricted our ability to determine the characteristics and distribution of major structural elements of the Chicxulub crater. The amplitude of the analytic signal produces maxima over magnetization contrasts, independent of the direction of magnetization. Interpretation of maxima location and depth distribution is used, in a second stage, as a priori information in the construction of an input prism assemblage magnetic configuration and its properties for three-dimensional forward modeling. Results indicate that magnetic sources extend to a radial distance of ∼45. km from the center of the structure with average depths ranging between 2 and 4. km. The magnetic anomaly sources in the central structural uplift zone are located in the range from 3.5 to 8. km depth, with dominant contributions from an apparent large body forming the basement uplift. © 2010 Elsevier B.V. 2010 10.1016/j.pepi.2010.01.007 Physics of the Earth and Planetary Interiors 179 127-138 Instituto Mexicano del Petroleo, Avenida de los Cien Metros 152, 07730 Mexico, D.F., Mexico; Proyecto Universitario de Perforaciones en Oceanos y Continentes, Instituto de Geofisica, Universidad Nacional Autonoma de Mexico, 04510 Mexico D.F., Mexico 3-4 https://www.scopus.com/inward/record.uri?eid=2-s2.0-77951090728&doi=10.1016%2fj.pepi.2010.01.007&partnerID=40&md5=25bf81ec76a2f8a5e97566ec741d6a1a cited By 27 C. Ortiz-Aleman J. Urrutia-Fucugauchi article Khanaeva201038 Microbial communities in the bottom sediments of the Akademichesky Ridge, Lake Baikal, were studied. The samples were taken by deep drilling BDP-96 (a 100-m core). Vertical distribution of the prokaryotes with different physiological characteristics was studied for the core. The phylogenetic analysis of the organotrophic laboratory-reared microorganisms revealed the clusterization of Baikal strains and species which have not been identified yet. © Pleiades Publishing, Ltd., 2010. Article 2010 English 19950837 10.1134/S1995082910010050 Inland Water Biology 3 38 – 43 1 Akademichesky Ridge; Lake Baikal; Russian Federation; Prokaryota; deep drilling; lacustrine deposit; microbial community; phylogenetics; physiology; prokaryote; species diversity; vertical distribution https://www.scopus.com/inward/record.uri?eid=2-s2.0-77949746365&doi=10.1134%2fS1995082910010050&partnerID=40&md5=e14d6d905a21ecd059f77f88a43f7b29 Cited by: 2 T.A. Khanaeva T.I. Zemskaya N.L. Bel'kova O.M. Khlystov B.B. Namsaraev article Su2010873 It has long been a dream for mankind to enter the deep Earth to sample and investigate the structures and inner geological progresses. Until now, scientific drilling has been the unique method in our understanding of the processes and structures of the Earth. This paper try to give a brief introduction of the history, the development, the mission, the structure and management, the membership, the project development scheme of International Continental Drilling Program (ICDP). Great advances have been brought about in many fields of earth sciences by continental scientific drilling in recent years. Based on the recent publications and website materials of ICDP, this paper summarize the main developments in Climate Dynamics and Global Environments, in the Study of Impact Craters, in the GeoBiospherc, in Active Volcanic Systems, in Active Faults, in Hotspot Volcanoes, in Convergent Plate Boundaries and Collision Zones, and in Natural Resources. Special introduction on the scientific results of ICDP drilling at Mt. Unzen, Japan and the Hawaii Scientific Drilling Project (HSDP) is introduced in this paper. Fascinating discoveries such as the gouge layer of San Andreas Fault and the finding of talc in cuttings of SAFOD project are also introduced in this paper. As one of the three founding members of ICDP, China has also gained a lot of developments in continental scientific drilling; typical examples are the achievements of Chinese Continental Scientific Drilling (CCSD) and the progress of Lake Qinghai Scientific Drilling Project. The preliminary progresses . of the third approved ICDP project of China -the Chinese Cretaceous Continental Scientific Drilling Project and the development of ICDP-China are also summarized in this paper. 2010 Chinese 10009515 Acta Geologica Sinica (English Edition) 84 873-886 Key Laboratory for Continental Dynamics of MLR, Institute of Geology, Chinese Academy of Geological Sciences, Beijing, 100037, China 6 active fault; climate change; collision zone; crater; deep drilling; hot spot; mantle plume; natural resource; San Andreas Fault; talc, China; Hawaii [United States]; Japan; Kyushu; Nagasaki [Kyushu]; Qinghai; Qinghai Lake; United States; Unzen Volcano https://www.scopus.com/inward/record.uri?eid=2-s2.0-78649844329&partnerID=40&md5=732f4e363917ab0357a84117ef5aab8b cited By 9 D. Su J. Yang article Su2010873 It has long been a dream for mankind to enter the deep Earth to sample and investigate the structures and inner geological progresses. Until now, scientific drilling has been the unique method in our understanding of the processes and structures of the Earth. This paper try to give a brief introduction of the history, the development, the mission, the structure and management, the membership, the project development scheme of International Continental Drilling Program (ICDP). Great advances have been brought about in many fields of earth sciences by continental scientific drilling in recent years. Based on the recent publications and website materials of ICDP, this paper summarize the main developments in Climate Dynamics and Global Environments, in the Study of Impact Craters, in the GeoBiospherc, in Active Volcanic Systems, in Active Faults, in Hotspot Volcanoes, in Convergent Plate Boundaries and Collision Zones, and in Natural Resources. Special introduction on the scientific results of ICDP drilling at Mt. Unzen, Japan and the Hawaii Scientific Drilling Project (HSDP) is introduced in this paper. Fascinating discoveries such as the gouge layer of San Andreas Fault and the finding of talc in cuttings of SAFOD project are also introduced in this paper. As one of the three founding members of ICDP, China has also gained a lot of developments in continental scientific drilling; typical examples are the achievements of Chinese Continental Scientific Drilling (CCSD) and the progress of Lake Qinghai Scientific Drilling Project. The preliminary progresses . of the third approved ICDP project of China -the Chinese Cretaceous Continental Scientific Drilling Project and the development of ICDP-China are also summarized in this paper. 2010 Chinese 10009515 Acta Geologica Sinica (English Edition) 84 873-886 Key Laboratory for Continental Dynamics of MLR, Institute of Geology, Chinese Academy of Geological Sciences, Beijing, 100037, China 6 active fault; climate change; collision zone; crater; deep drilling; hot spot; mantle plume; natural resource; San Andreas Fault; talc, China; Hawaii [United States]; Japan; Kyushu; Nagasaki [Kyushu]; Qinghai; Qinghai Lake; United States; Unzen Volcano https://www.scopus.com/inward/record.uri?eid=2-s2.0-78649844329&partnerID=40&md5=732f4e363917ab0357a84117ef5aab8b cited By 9 D. Su J. Yang article Su2010873 It has long been a dream for mankind to enter the deep Earth to sample and investigate the structures and inner geological progresses. Until now, scientific drilling has been the unique method in our understanding of the processes and structures of the Earth. This paper try to give a brief introduction of the history, the development, the mission, the structure and management, the membership, the project development scheme of International Continental Drilling Program (ICDP). Great advances have been brought about in many fields of earth sciences by continental scientific drilling in recent years. Based on the recent publications and website materials of ICDP, this paper summarize the main developments in Climate Dynamics and Global Environments, in the Study of Impact Craters, in the GeoBiospherc, in Active Volcanic Systems, in Active Faults, in Hotspot Volcanoes, in Convergent Plate Boundaries and Collision Zones, and in Natural Resources. Special introduction on the scientific results of ICDP drilling at Mt. Unzen, Japan and the Hawaii Scientific Drilling Project (HSDP) is introduced in this paper. Fascinating discoveries such as the gouge layer of San Andreas Fault and the finding of talc in cuttings of SAFOD project are also introduced in this paper. As one of the three founding members of ICDP, China has also gained a lot of developments in continental scientific drilling; typical examples are the achievements of Chinese Continental Scientific Drilling (CCSD) and the progress of Lake Qinghai Scientific Drilling Project. The preliminary progresses . of the third approved ICDP project of China -the Chinese Cretaceous Continental Scientific Drilling Project and the development of ICDP-China are also summarized in this paper. 2010 Chinese 10009515 Acta Geologica Sinica (English Edition) 84 873-886 Key Laboratory for Continental Dynamics of MLR, Institute of Geology, Chinese Academy of Geological Sciences, Beijing, 100037, China 6 active fault; climate change; collision zone; crater; deep drilling; hot spot; mantle plume; natural resource; San Andreas Fault; talc, China; Hawaii [United States]; Japan; Kyushu; Nagasaki [Kyushu]; Qinghai; Qinghai Lake; United States; Unzen Volcano https://www.scopus.com/inward/record.uri?eid=2-s2.0-78649844329&partnerID=40&md5=732f4e363917ab0357a84117ef5aab8b cited By 9 D. Su J. Yang article Su2010873 It has long been a dream for mankind to enter the deep Earth to sample and investigate the structures and inner geological progresses. Until now, scientific drilling has been the unique method in our understanding of the processes and structures of the Earth. This paper try to give a brief introduction of the history, the development, the mission, the structure and management, the membership, the project development scheme of International Continental Drilling Program (ICDP). Great advances have been brought about in many fields of earth sciences by continental scientific drilling in recent years. Based on the recent publications and website materials of ICDP, this paper summarize the main developments in Climate Dynamics and Global Environments, in the Study of Impact Craters, in the GeoBiospherc, in Active Volcanic Systems, in Active Faults, in Hotspot Volcanoes, in Convergent Plate Boundaries and Collision Zones, and in Natural Resources. Special introduction on the scientific results of ICDP drilling at Mt. Unzen, Japan and the Hawaii Scientific Drilling Project (HSDP) is introduced in this paper. Fascinating discoveries such as the gouge layer of San Andreas Fault and the finding of talc in cuttings of SAFOD project are also introduced in this paper. As one of the three founding members of ICDP, China has also gained a lot of developments in continental scientific drilling; typical examples are the achievements of Chinese Continental Scientific Drilling (CCSD) and the progress of Lake Qinghai Scientific Drilling Project. The preliminary progresses . of the third approved ICDP project of China -the Chinese Cretaceous Continental Scientific Drilling Project and the development of ICDP-China are also summarized in this paper. Article 2010 Chinese 10009515 Acta Geologica Sinica (English Edition) 84 873 – 886 6 China; Hawaii [United States]; Japan; Kyushu; Nagasaki [Kyushu]; Qinghai; Qinghai Lake; United States; Unzen Volcano; active fault; climate change; collision zone; crater; deep drilling; hot spot; mantle plume; natural resource; San Andreas Fault; talc https://www.scopus.com/inward/record.uri?eid=2-s2.0-78649844329&partnerID=40&md5=732f4e363917ab0357a84117ef5aab8b Cited by: 9 article Fowler2010731 Recent experimental work has shown that, when a vertical column of rock under large pressure is suddenly depressurized, the column can 'explode' in a structured and repeatable way. The observations show that a sequence of horizontal fractures forms from the top down, and the resulting blocks are lifted off and ejected. The blocks can suffer secondary internal fractures. This experiment provides a framework for understanding the way in which catastrophic explosion can occur, and is motivated by the corresponding phenomenon of magmatic explosion during Vulcanian eruptions. We build a theoretical model to describe these results, and show that it is capable of describing both the primary sequence of fracturing and the secondary intrablock fracturing. The model allows us to suggest a practical criterion for when such explosions occur: firstly, the initial confining pressure must exceed the yield stress of the rock, and, secondly, the diffusion of the gas by porous flow must be sufficiently slow that a large excess pore pressure is built up. This will be the case if the rock permeability is small enough. © 2010 The Royal Society. 2010 English 13645021 10.1098/rspa.2009.0382 Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 466 Royal Society 731-752 MACSI, Department of Mathematics and Statistics, University of Limerick, Limerick, Ireland; Earth and Environmental Sciences, LMU München, Theresienstrasse 41/111, 80333 München, Germany; School of Mathematics, Statistics and Operations Research, Victoria University of Wellington, New Zealand 2115 Brittle fracture; Explosions; Nitration; Submarine geophysics; Yield stress, Brittle fragmentation; Catastrophic explosion; Confining pressures; Excess pore pressure; Explosive fragmentation; Explosive volcanism; Horizontal fractures; Internal fracture; Magma fragmentation; Magmatic explosion; Porous flow; Primary sequences; Rock permeability; Silicic magmas; Theoretical models; Topdown; Vertical columns, Explosives https://www.scopus.com/inward/record.uri?eid=2-s2.0-75949126427&doi=10.1098%2frspa.2009.0382&partnerID=40&md5=e05ac6a65261045d3008d5be257730f0 cited By 35 A.C. Fowler B. Scheu W.T. Lee M.J. McGuinness article Kikuchi201014 The extinction pattern of the Maastrichtian indicates that long-term and short-term events contributed to the Cretaceous-Tertiary (K-T) mass extinction at 65 Ma. However, it is not clear how the impact events are linked with the extinction selectivity; e.g. non-avian dinosaurs became extinct, whereas birds survived. The post-impact air quality is discussed, and attention is focused on the then land vertebrates. Although ground-level (tropospheric) O3 is a powerful irritant on the order of 0.1 ppm toxicity, the presence of ground-level O3 has hardly been considered since the K-T impact theory was reported about 30 years ago. Under the post-impact conditions reconstructed by simulating the carbon cycle (including isotope balance) and impact chemistry, a trajectory model suggests that the then photochemical reactions formed ground-level O3 whose concentration was apparently low at ∼ 1.0 ppm, but it is much greater than the current level of ∼ 0.04 ppm: that is, an O3 concentration above the health-threatening level persisted on the ground after the K-T impact. All land vertebrates must have suffered from respiratory O3 irritation at the time. However, analysis suggests that variables of O3 characteristics - hourly variation, short half-life in water and decomposition due to catalytic effects in soil - were randomly combined with variables of lifestyle features such as habitat, torpor, etc. to form new variables (i.e. survival rates): a high survival probability for amphibians; middle/high probabilities for semi-aquatic reptiles, mammals and birds; low/middle probabilities for marsupials and terrestrial reptiles; and a zero probability for non-avian dinosaurs. © 2010 Elsevier B.V. All rights reserved. 2010 10.1016/j.palaeo.2010.01.027 Palaeogeography, Palaeoclimatology, Palaeoecology 288 14-23 ESAC - Instituto Politécnico de Coimbra, Bencanta, 3040-316 Coimbra, Portugal; Norwegian Geotechnical Institute, Sognsveien 72, 0806 Oslo, Norway 1-4 https://www.scopus.com/inward/record.uri?eid=2-s2.0-77649234062&doi=10.1016%2fj.palaeo.2010.01.027&partnerID=40&md5=ef6f70131bd8b51ca8028acc9b8b0f54 cited By 6 R. Kikuchi M. Vanneste article Vogel2010320 Here we present a tephrostratigraphic record (core Co1202) recovered from the northeastern part of Lake Ohrid (Republics of Macedonia and Albania) reaching back to Marine Isotope Stage (MIS) 6. Overall ten horizons (OT0702-1 to OT0702-10) containing volcanic tephra have been recognised throughout the 14.94m long sediment succession. Four tephra layers were visible at macroscopic inspection (OT0702-4, OT0702-6, OT0702-8 and OT0702-9), while the remaining six are cryptotephras (OT0702-1, OT0702-2, OT0702-3, OT0702-5, OT0702-7 and OT0702-10) identified from peaks in K, Zr and Sr intensities, magnetic susceptibility measurements, and washing and sieving of the sediments. Glass shards of tephra layers and cryptotephras were analysed with respect to their major element composition, and correlated to explosive eruptions of Italian volcanoes. The stratigraphy and the major element composition of tephra layers and cryptotephras allowed the correlation of OT0702-1 to AD 472 or AD 512 eruptions of Somma-Vesuvius, OT0702-2 to the FL eruption of Mount Etna, OT0702-3 to the Mercato from Somma-Vesuvius, OT0702-4 to SMP1-e/Y-3 eruption from the Campi Flegrei caldera, OT0702-5 to the Codola eruption (Somma-Vesuvius or Campi Flegrei), OT0702-6 to the Campanian Ignimbrite/Y-5 from the Campi Flegrei caldera, OT0702-7 to the Green Tuff/Y-6 eruption from Pantelleria Island, OT0702-8 to the X-5 eruption probably originating from the Campi Flegrei caldera, OT0702-9 to the X-6 eruption of generic Campanian origin, and OT0702-10 to the P-11 eruption from Pantelleria Island. The fairly well-known ages of these tephra layers and parent eruptions provide new data on the dispersal and deposition of these tephras and, furthermore, allow the establishment of a chronological framework for core Co1202 for a first interpretation of major sedimentological changes. © 2009 John Wiley & Sons, Ltd. Article 2010 English 10991417 10.1002/jqs.1311 Journal of Quaternary Science 25 320 – 338 3 Albania; Greece; Lake Ohrid; Macedonia [Greece]; caldera; Campanian; ignimbrite; Last Glacial-Interglacial; magnetic susceptibility; marine isotope stage; potassium; stratigraphy; strontium; tephra; tephrochronology; tuff; volcanic eruption; X-ray fluorescence; zircon https://www.scopus.com/inward/record.uri?eid=2-s2.0-77449087250&doi=10.1002%2fjqs.1311&partnerID=40&md5=4f33163495f69733dfafd2bc43191465 Cited by: 101 Hendrik Vogel Giovanni Zanchetta Roberto Sulpizio Bernd Wagner Norbert Nowaczyk article Vogel2010295 Lake Ohrid is probably of Pliocene age, and the oldest extant lake in Europe. In this study climatic and environmental changes during the last glacial-interglacial cycle are reconstructed using lithological, sedimentological, geochemical and physical proxy analysis of a 15-m-long sediment succession from Lake Ohrid. A chronological framework is derived from tephrochronology and radiocarbon dating, which yields a basal age of ca. 136 ka. The succession is not continuous, however, with a hiatus between ca. 97. 6 and 81. 7 ka. Sediment accumulation in course of the last climatic cycle is controlled by the complex interaction of a variety of climate-controlled parameters and their impact on catchment dynamics, limnology, and hydrology of the lake. Warm interglacial and cold glacial climate conditions can be clearly distinguished from organic matter, calcite, clastic detritus and lithostratigraphic data. During interglacial periods, short-term fluctuations are recorded by abrupt variations in organic matter and calcite content, indicating climatically-induced changes in lake productivity and hydrology. During glacial periods, high variability in the contents of coarse silt to fine sand sized clastic matter is probably a function of climatically-induced changes in catchment dynamics and wind activity. In some instances tephra layers provide potential stratigraphic markers for short-lived climate perturbations. Given their widespread distribution in sites across the region, tephra analysis has the potential to provide insight into variation in the impact of climate and environmental change across the Mediterranean. © 2010 Springer Science+Business Media B.V. Article 2010 English 09212728 10.1007/s10933-009-9404-x Journal of Paleolimnology 44 295 – 310 1 Albania; Greece; Lake Ohrid; Macedonia [Greece]; accumulation rate; climate variation; geochemical method; Last Glacial-Interglacial; lithology; lithostratigraphy; paleoclimate; paleolimnology; Pliocene; proxy climate record; radiocarbon dating; sedimentology; tephrochronology https://www.scopus.com/inward/record.uri?eid=2-s2.0-77952670412&doi=10.1007%2fs10933-009-9404-x&partnerID=40&md5=2c14af903bbafd634034c28461f4a912 Cited by: 134; All Open Access, Green Open Access Hendrik Vogel Bernd Wagner Giovanni Zanchetta Roberto Sulpizio Peter Rosén article Chapligin20102655 The determination of the oxygen isotope composition of diatom silica in sediment cores is important for paleoclimate reconstruction, especially in non-carbonate sediments, where no other bioindicators such as ostracods and foraminifera are available. Since most currently available analytical techniques are time-consuming and labour-intensive, we have developed a new, safer, faster and semi-automated online approach for measuring oxygen isotopes in biogenic silica. Improvements include software that controls the measurement procedures and a video camera that remotely records the reaction of the samples under BrF5 with a CO2 laser. Maximum safety is guaranteed as the laserfluorination unit is arranged under a fume hood in a separate room from the operator. A new routine has been developed for removing the exchangeable hydrous components within biogenic silica using ramp degassing. The sample plate is heated up to 1100°C and cooled down to 400°C in ~7 h under a flow of He gas (the inert Gas Flow Dehydration method - iGFD) before isotope analysis. Two quartz and two biogenic silica samples (~1.5 mg) of known isotope composition were tested. The isotopic compositions were reproducible within an acceptable error; quartz samples gave a mean standard deviation of &lt;0.15%(1σ) and for biogenic silica &lt;0.25%(1σ) for samples down to ~0.3 mg. The semiautomated fluorination line is the fastest method available at present and enables a throughput of 74 samples/week. © 2010 John Wiley &amp; Sons, Ltd. 2010 English 09514198 10.1002/rcm.4689 Rapid Communications in Mass Spectrometry 24 2655-2664 Alfred Wegener Institute for Polar and Marine Research, Research Unit Potsdam, Telegrafenberg A43, D-14473 Potsdam, Germany; Free University of Berlin, Institute of Geological Sciences, Malteserstr. 74-100, Berlin, D-12249, Germany; Technical University of Berlin, Straße des 17. Juni 135, D-10623 Berlin, Germany; MS-Analysentechnik, Aßmannshauser Str.12, D-14197 Berlin, Germany 17 helium; oxygen; silicon dioxide, article; chemistry; desiccation; diatom; instrumentation; ion exchange; isolation and purification; laboratory automation; methodology; paleontology; reproducibility; sensitivity and specificity, Automation, Laboratory; Desiccation; Diatoms; Helium; Ion Exchange; Oxygen Isotopes; Paleontology; Quartz; Reproducibility of Results; Sensitivity and Specificity; Silicon Dioxide https://www.scopus.com/inward/record.uri?eid=2-s2.0-77955385336&doi=10.1002%2frcm.4689&partnerID=40&md5=4ba1352c9eb3f745d563f2533ef2c1b4 cited By 38 B. Chapligin H. Meyer H. Friedrichsen A. Marent E. Sohns H.-W. Hubberten article Kostoski20103999 Immediate conservation measures for world-wide freshwater resources are of eminent importance. This is particularly true for so-called ancient lakes. While these lakes are famous for being evolutionary theatres, often displaying an extraordinarily high degree of biodiversity and endemism, in many cases these biota are also experiencing extreme anthropogenic impact. Lake Ohrid, a major European biodiversity hotspot situated in a trans-frontier setting on the Balkans, is a prime example for a lake with a magnitude of narrow range endemic taxa that are under increasing anthropogenic pressure. Unfortunately, evidence for a "creeping biodiversity crisis" has accumulated over the last decades, and major socio-political changes have gone along with human-mediated environmental changes. Based on field surveys, monitoring data, published records, and expert interviews, we aimed to (1) assess threats to Lake Ohrids' (endemic) biodiversity, (2) summarize existing conservation activities and strategies, and (3) outline future conservation needs for Lake Ohrid. We compiled threats to both specific taxa (and in cases to particular species) as well as to the lake ecosystems itself. Major conservation concerns identified for Lake Ohrid are: (1) watershed impacts, (2) agriculture and forestry, (3) tourism and population growth, (4) non-indigenous species, (5) habitat alteration or loss, (6) unsustainable exploitation of fisheries, and (7) global climate change. Among the major (well-known) threats with high impact are nutrient input (particularly of phosphorus), habitat conversion and silt load. Other threats are potentially of high impact but less well known. Such threats include pollution with hazardous substances (from sources such as mines, former industries, agriculture) or climate change. We review and discuss institutional responsibilities, environmental monitoring and ecosystem management, existing parks and reserves, biodiversity and species measures, international conservation activities, and ongoing research on conservation and raising of public awareness. Following this summary, we evaluate the status quo and future of Lake Ohrid and its biota. A comprehensive conservation strategy should include measures that result in an immediate reduction of nutrient input, particularly with phosphorus, in order to slow down the ongoing eutrophication process. The existing watershed management should become more effective. Implementation and particularly with a view to the enforcement of national laws should be enhanced. Increased research on the lakes' limnology, biodiversity, and conservation management practices are necessary. The latter research should identify conservation priorities. Public awareness should be enhanced. Facing these parallel needs to protect the unique biodiversity of Lake Ohrid, we suggest urging (a) implementation and enforcement of the General Management Plan that would ensure long-term integrated and sustainable use of the lake and its watershed, (b) scientific studies on ecology, biodiversity and effects of human impact, (c) the establishment of Core Conservation areas (CCA), including underwater reserves, and (d) Coastal Zone Management (CZM) areas that would constitute buffer zones for the CCAs around the lake. Given the number of identified threats, it is clear that only concerted international action can stop or at least slow down further degradation of Lake Ohrid and the creeping biodiversity crisis already evident. All conservation activities should, among others, ultimately lead to a trans-boundary major conservation area of the Ohrid-Prespa region that would allow long-term integration of both humans and nature. © Author(s) 2010. Article 2010 English 17264189 10.5194/bg-7-3999-2010 Biogeosciences 7 3999 – 4015 12 Lake Ohrid; anthropogenic effect; biodiversity; buffer zone; coastal zone management; eutrophication; future prospect; habitat conservation; hot spot; lake ecosystem https://www.scopus.com/inward/record.uri?eid=2-s2.0-78650566957&doi=10.5194%2fbg-7-3999-2010&partnerID=40&md5=c36d6c7a39e95efd1e2f57e698276f1c Cited by: 35; All Open Access, Gold Open Access, Green Open Access G. Kostoski C. Albrecht S. Trajanovski T. Wilke article Swann2010774 Determining the response of sites within the Arctic Circle to long-term climatic change remains an essential pre-requisite for assessing the susceptibility of these regions to future global warming and Arctic amplification. To date, existing records from North East Russia have demonstrated significant spatial variability across the region during the late Quaternary. Here we present diatom δ18O and δ30Si data from Lake El'gygytgyn, Russia, and suggest environmental changes that would have impacted across West Beringia from the Last Glacial Maximum to the modern day. In combination with other records, the results raise the potential for climatic teleconnections to exist between the region and sites in the North Atlantic. The presence of a series of 2-3‰ decreases in δ18Odiatom during both the Last Glacial and the Holocene indicates the sensitivity of the region to perturbations in the global climate system. Evidence of an unusually long Holocene thermal maximum from 11.4 ka BP to 7.6 ka BP is followed by a cooling trend through the remainder of the Holocene in response to changes in solar insolation. This is culminated over the last 900 years by a significant decrease in δ18Odiatom of 2.3‰, which may be related to a strengthening and easterly shift of the Aleutian Low in addition to possible changes in precipitation seasonality. © 2009 Elsevier Ltd. All rights reserved. 2010 English 02773791 10.1016/j.quascirev.2009.11.024 Quaternary Science Reviews 29 774-786 NERC Isotope Geosciences Laboratory, British Geological Survey, Keyworth, Nottingham, NG12 5GG, United Kingdom; School of Geography, University of Nottingham, Nottingham, NG7 2RD, United Kingdom; Institute of Geology and Mineralogy, University of Cologne, Zülpicher Str. 49a, D-50674 Cologne, Germany; Department of Geosciences, University of Massachusetts, Amherst, MA 01003, United States 5-6 Aleutian low; Arctic Circle; Climatic changes; Cooling trends; Environmental change; Global climate system; Holocenes; Isotope record; Last glacial; Last Glacial Maximum; Late quaternary; North Atlantic; North-East Siberia; Seasonality; Solar insolation; Spatial variability; Teleconnections; Thermal maxima, Amplification; Global warming; Isotopes; Oxygen, Glacial geology, climate variation; Holocene; isotopic analysis; oxygen isotope; perturbation; silicon; spatial variation, Atlantic Ocean; Atlantic Ocean (North); Chukchi; Elgygytgyn Lake; Russian Federation, Bacillariophyta https://www.scopus.com/inward/record.uri?eid=2-s2.0-76449095430&doi=10.1016%2fj.quascirev.2009.11.024&partnerID=40&md5=d1cd57b3af5bb3187f2316c32e97c3f1 cited By 55 G.E.A. Swann M.J. Leng O. Juschus M. Melles J. Brigham-Grette H.J. Sloane article Ormö20101206 To better understand the impact cratering process and its environmental consequences at the local to global scale, it is important to know when in the geological record of an impact crater the impact-related processes cease. In many instances, this occurs with the end of early crater modification, leaving an obvious sedimentological boundary between impactites and secular sediments. However, in marine-target craters the transition from early crater collapse (i.e., water resurge) to postimpact sedimentation can appear gradual. With the a priori assumption that the reworked target materials of the resurge deposits have a different chemical composition to the secular sediments we use chemostratigraphy (δ13Ccarb, %Corg, major elements) of sediments from the Chesapeake Bay, Lockne, and Tvären craters, to define this boundary. We show that the end of impact-related sedimentation in these cases is fairly rapid, and does not necessarily coincide with a visual boundary (e.g., grain size shift). Therefore, in some cases, the boundary is more precisely determined by chemostratigraphy, especially carbonate carbon isotope variations, rather than by visual inspection. It is also shown how chemostratigraphy can confirm the age of marine-target craters that were previously determined by biostratigraphy; by comparing postimpact carbon isotope trends with established regional trends. © The Meteoritical Society, 2010. 2010 English 10869379 10.1111/j.1945-5100.2010.01084.x Meteoritics and Planetary Science 45 University of Arkansas 1206-1224 Centro de Astrobiología (CSIC-INTA), Instituto Nacional de Técnica Aeroespacial, 28850 Torrejón de Ardoz, Madrid, Spain; U.S. Geological Survey, 926A National Center, Reston, VA 20192, United States 7 https://www.scopus.com/inward/record.uri?eid=2-s2.0-78049441916&doi=10.1111%2fj.1945-5100.2010.01084.x&partnerID=40&md5=4dcfa8a6fdb6a987f134cc480f071733 cited By 12 J. Ormö A.C. Hill J.M. Self-Trail article Kalleson2010798 Melt-bearing impactites dominated by suevite, and with a minor content of clast-rich impact melt rock, are found within the central part of the Gardnos structure. They are preserved as the eroded remnants in the relatively small complex impact structure with a present diameter of 5 km. These rocks have been mapped in the field and in the Branden drill core, and described according to mineralogy/petrology, including matrix, litho clast, and melt content, as well as geochemistry. Based on our extensive field mapping, a simple 3-D model of the original crater was constructed to estimate tentative volumes for the melt-bearing impactites. The variations in lithic and melt fragment content and chemistry of suevite matrix can mostly be explained by incorporation of mafic rocks into a dominant mixture of granitic, gneissic, and quartzitic target rocks, reflecting mixing of material from different parts of the crater. Melt fragments within suevite occur with a variety of shapes and textures, probably related to different original target rock composition, to the various temperatures the individual fragments were subjected to during the impact event and deposition processes. This study discusses the impact-related deposits based on a sedimentological approach. Their overall composition and structures indicate dominating gravity flow processes in the final transportation and deposition of the suevite. © 2010 The Meteoritical Society. 2010 10.1111/j.1945-5100.2010.01055.x Meteoritics and Planetary Science 45 798-827 Department of Geosciences, University of Oslo, P.O. 1047, Blindern, NO-0316 Oslo, Norway; Natural History Museum, University of Oslo, P.O. 172, Blindern, NO-0318 Oslo, Norway 5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-77956573774&doi=10.1111%2fj.1945-5100.2010.01055.x&partnerID=40&md5=25280fe6865b1db7f4df449937105109 cited By 14 E. Kalleson H. Dypvik O. Nilsen article Pérez2010146 We analyzed modern ostracode species assemblages and water column physico-chemical characteristics in Lago Péten Itzá, Guatemala. Lake waters are dominated by sulfate, bicarbonate, calcium and magnesium and display a total ion concentration of ~11 meq L-1. Eleven extant ostracode species were identified. We found higher abundances of living ostracodes, as well as relatively higher species richness (eight species) and biodiversity (H of 1.6) between the littoral zone and a water depth of <20 m. At water depths >40 m, these variables all decreased. The thermocline is located at a water depth of ~20-40 m. Cluster analysis revealed three water depth ranges in the lake of importance to ostracode distribution: 1) littoral zone (0.1-3 m), 2) water depths from the base of the littoral zone to the base of the thermocline (3-40 m), and 3) water depths below the thermocline (40-160 m). The assemblage Darwinula-Heterocypris-Pseudocandona-Strandesia is characteristic of waters <15 m. The Cypridopsis-Cytheridella-Limnocythere assemblage characterizes waters <40 m and Physocypria indicates waters >40 m. Ostracode taxa from Lago Petén Itzá show specific ecological preferences related to water depth and associated physico-chemical characteristics, thus illustrating the potential of ostracodes as indicators of lake level changes and hydrodynamics. Article 2010 Feb. English 11295767 10.3274/JL10-69-1-14 Journal of Limnology 69 146 – 159 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-77956866062&doi=10.3274%2fJL10-69-1-14&partnerID=40&md5=55526e64bba06d9068c55d92858098e0 Cited by: 41 Liseth Pérez Julia Lorenschat Rita Bugja Mark Brenner Burkhard Scharf Antje Schwalb article Su2010873 It has long been a dream for mankind to enter the deep Earth to sample and investigate the structures and inner geological progresses. Until now, scientific drilling has been the unique method in our understanding of the processes and structures of the Earth. This paper try to give a brief introduction of the history, the development, the mission, the structure and management, the membership, the project development scheme of International Continental Drilling Program (ICDP). Great advances have been brought about in many fields of earth sciences by continental scientific drilling in recent years. Based on the recent publications and website materials of ICDP, this paper summarize the main developments in Climate Dynamics and Global Environments, in the Study of Impact Craters, in the GeoBiospherc, in Active Volcanic Systems, in Active Faults, in Hotspot Volcanoes, in Convergent Plate Boundaries and Collision Zones, and in Natural Resources. Special introduction on the scientific results of ICDP drilling at Mt. Unzen, Japan and the Hawaii Scientific Drilling Project (HSDP) is introduced in this paper. Fascinating discoveries such as the gouge layer of San Andreas Fault and the finding of talc in cuttings of SAFOD project are also introduced in this paper. As one of the three founding members of ICDP, China has also gained a lot of developments in continental scientific drilling; typical examples are the achievements of Chinese Continental Scientific Drilling (CCSD) and the progress of Lake Qinghai Scientific Drilling Project. The preliminary progresses . of the third approved ICDP project of China -the Chinese Cretaceous Continental Scientific Drilling Project and the development of ICDP-China are also summarized in this paper. 2010 Chinese 10009515 Acta Geologica Sinica (English Edition) 84 873-886 Key Laboratory for Continental Dynamics of MLR, Institute of Geology, Chinese Academy of Geological Sciences, Beijing, 100037, China 6 active fault; climate change; collision zone; crater; deep drilling; hot spot; mantle plume; natural resource; San Andreas Fault; talc, China; Hawaii [United States]; Japan; Kyushu; Nagasaki [Kyushu]; Qinghai; Qinghai Lake; United States; Unzen Volcano https://www.scopus.com/inward/record.uri?eid=2-s2.0-78649844329&partnerID=40&md5=732f4e363917ab0357a84117ef5aab8b cited By 9 D. Su J. Yang article Farnetani2010231 A thorough understanding of the internal structure of the Hawaiian plume conduit requires to link geochemical observations of surface lavas to fluid dynamic simulations able to quantify the flow trajectories of upwelling geochemical heterogeneities and their sampling by volcanoes. With the present work we fill a gap between the numerous geochemical studies of Hawaiian lavas and the paucity of dynamical models that relate the observed geochemical record to the internal plume structure. Our three-dimensional numerical simulation of a vigorous plume sheared by a fast moving oceanic plate shows that the dominant deformation in the conduit is vertical stretching, while horizontal spreading and vertical shortening prevail in the sublithospheric part of the plume (hereafter referred to as plume head). Flow trajectories indicate that a young volcano like Loihi samples the 'upstream' side of the plume, not its center, whereas volcanoes in the post-shield phase sample deep melts from the 'downstream' side of the plume. To constrain the internal conduit structure we focus on two geochemical observations: old (>350 kyr) Mauna Kea lavas from the Hawaii Scientific Drilling Project are isotopically distinct from recent Mauna Kea lavas, but they are isotopically identical to present-day Kilauea lavas. By modelling a plume conduit with several long-lasting filaments of 10. km radius, we find that the isotopic record of a volcano (e.g., Mauna Kea) is expected to change over time-scales of ~400. kyr. Furthermore, by requiring that two age progressive volcanoes (e.g., Mauna Kea and Kilauea) sample the same filament, we constrain the minimum filament length to be ~600. km. In this paper we adopt a 'top-down' approach: from geochemical observations of surface lavas, to dynamical models of the conduit structure, and further down to the 'geochemical architecture' of the thermal boundary layer feeding the plume. A conduit structure with filaments maps back into heterogeneous volumes with azimuthal and radial extents of several hundred kilometers in the source region of plumes. © 2010 Elsevier B.V. Article 2010 English 0012821X 10.1016/j.epsl.2010.04.005 Earth and Planetary Science Letters 295 231 – 240 1-2 Hawaii [United States]; United States; Computer simulation; Filaments (lamp); Conduit structure; Dynamical model; Fluid dynamic simulation; Geochemical heterogeneity; Internal structure; Isotopic record; Kilauea; Long lasting; Mantle heterogeneity; Oceanic plate; Phase samples; Plume dynamics; Plume structure; Scientific drilling; Source region; Thermal boundary layer; Three-dimensional numerical simulations; Time-scales; Topdown; fluid dynamics; igneous geochemistry; isotopic composition; lava; mantle plume; simulation; volcano; Volcanoes https://www.scopus.com/inward/record.uri?eid=2-s2.0-77953024036&doi=10.1016%2fj.epsl.2010.04.005&partnerID=40&md5=f96941980f7d8440fc7c46858bbf0b5a Cited by: 74 Cinzia G. Farnetani Albrecht W. Hofmann article Marks2010172 The Reykjanes geothermal system is a seawater-recharged hydrothermal system that appears to be analogous to seafloor hydrothermal systems in terms of host rock type and low water/rock alteration. The similarities make the Reykjanes system a useful proxy for seafloor vents. At some time during the Pleistocene, the system was dominated by meteoric water recharge, and fluid composition at Reykjanes has evolved through time as a result of changing proportions of meteoric water influx as well as differing pressure and temperature conditions. The purpose of this study is to characterize secondary mineralization, degree of metasomatic alteration, and bulk composition of cuttings from well RN-17 from the Reykjanes geothermal system. The basaltic host rock includes hyaloclastite, breccia, tuff, extrusive basalt, diabase, as well as a marine sedimentary sequence. The progressive hydrothermal alteration sequence observed with increasing depth results from reaction of geothermal fluids with the basaltic host rock. An assemblage of greenschist facies alteration minerals, including actinolite, prehnite, epidote and garnet, occurs at depths as shallow as 350 m; these minerals are commonly found in Icelandic geothermal systems at temperatures above 250 °C (Bird and Spieler, 2004). This requires hydrostatic pressures that exceed the present-day depth to boiling point curve, and therefore must record alteration at higher fluid pressures, perhaps as a result of Pleistocene glaciation. Major, minor, and trace element profiles of the cuttings indicate transitional MORB to OIB composition with limited metasomatic shifts in easily mobilized elements. Changes in MgO, K2O and loss on ignition indicate that metasomatism is strongly correlated with protolith properties. The textures of alteration minerals reveal alteration style to be strongly dependent on protolith as well. Hyaloclastites are intensely altered with calc-silicate alteration assemblages comprising calcic hydrothermal plagioclase, grandite garnet, prehnite, epidote, hydrothermal clinopyroxene, and titanite. In contrast, crystalline basalts and intrusive rocks display a range in alteration intensity from essentially unaltered to pervasive and nearly complete albitization of igneous feldspar and uralitization of clinopyroxene. Hydrothermal anorthite (An92-An98) occurs in veins in the most altered basalt cuttings and is significantly more calcic than igneous feldspar (An48-An79). Amphibole compositions change from actinolite to hornblende at depth. Hydrothermal clinopyroxene, which occurs in veins, has greater variation in Fe content and is systematically more calcic than igneous pyroxene and also lacks uralitic textures. Solid solutions of prehnite, epidote, and garnet indicate evolving equilibria with respect to aluminum and ferric iron. © 2009 Elsevier B.V. All rights reserved. 2010 English 03770273 10.1016/j.jvolgeores.2009.10.018 Journal of Volcanology and Geothermal Research 189 172-190 Department of Geology, University of California, Davis, CA 95616, United States; ISOR, Iceland GeoSurvey, Grensasvegur 9, 108 Reykjavik, Iceland; Hitaveita Sudurnesja Ltd. Brekkustigur 36, 260 Reykjanesbaer, Iceland 1-2 Albitization; Amphibole compositions; Bulk compositions; Clinopyroxenes; Deep drilling; Fe content; Ferric iron; Fluid composition; Fluid pressures; Geothermal fluids; Geothermal systems; Greenschist; Host rocks; Hyaloclastites; Hydrothermal alterations; Hydrothermal system; Icelandics; Icelands; Intrusive rocks; Loss on ignition; Meteoric waters; Pleistocene; Prehnite; Pressure and temperature; Protoliths; Sea floor; Seafloor hydrothermal systems; Sedimentary sequence, Basalt; Boiling point; Crystalline rocks; Feldspar; Garnets; Geothermal fields; Geothermal prospecting; Glacial geology; Hydrostatic pressure; Mineralogy; Minerals; Seawater; Sedimentary rocks; Silicate minerals; Textures; Trace elements; Underwater mineral resources; Well drilling, Igneous rocks, amphibole; basalt; breccia; diabase; geothermal system; host rock; hyaloclastite; hydrothermal alteration; hydrothermal system; mid-ocean ridge basalt; mineralization; Pleistocene; seafloor; solid solution; tuff; water-rock interaction, Iceland; Reykjanes Peninsula, Aves https://www.scopus.com/inward/record.uri?eid=2-s2.0-72649091290&doi=10.1016%2fj.jvolgeores.2009.10.018&partnerID=40&md5=c12f29a5ef60672a95a86cb0f6c27629 cited By 60 N. Marks P. Schiffman R.A. Zierenberg H. Franzson G.Ó. Fridleifsson article Coney2010411 A petrographic and geochemical comparison of suevites from the LB-07A and LB-08A cores recovered during 2004 by the International Continental Scientific Drilling Program with suevites from outside of the crater rim of the Bosumtwi impact structure indicates contrasting mechanisms of formation for these respective impact breccias. The within-crater suevites form only a small part of the lithic impact breccia-dominated impactite crater fill, in contrast to the impactites from outside of the crater, which consist solely of suevite. The clasts of suevites from within the crater display relatively low levels of shock (for most material <45 GPa). The numbers of shocked quartz grains, as well as fragments of diaplectic glass of quartz and feldspar in suevites decrease with depth through the LB-07A core (maximum three sets of planar deformation features [PDFs]). In contrast, the out-of-crater suevites sampled north and south of the crater contain up to four PDF sets in quartz clasts, ballen cristobalite, and higher proportions of diaplectic glass than the within-crater suevites. In addition, the suevites from outside of the crater contain significantly more melt particles (18-37 vol%) than the within-crater suevites (<5 vol%). Melt fragment sizes in suevites from outside the crater are much larger than those from suevites within the crater (maximum 40 cm versus 1 cm). The currently known distribution of impactites outside of the crater would be consistent with a low-angle impact from the east. We propose that the within-crater suevites and polymict lithic breccias were emplaced either via slumping off the crater walls or lateral movement of some melted and much displaced target rock within the crater. Limited admixture of fallback material from the ejecta plume is evident in the uppermost impactite deposit encountered in core LB-05B. In contrast, the out-of-crater suevites formed by fallout from a laterally differentiated ejecta plume, which resulted in different clast populations to the north and south of the crater. © 2010 The Geological Society of America. All rights reserved. 2010 10.1130/2010.2465(21) Special Paper of the Geological Society of America 465 411-442 Impact Cratering Research Group, School of Geosciences, University of the Witwatersrand, Private Bag 3, P.O. WITS, Johannesburg, 2050, South Africa; Museum für Naturkunde, Leibniz-Institute, Humboldt University Berlin, Invalidenstrasse 43, D-10115 Berlin, Germany; Department of Lithospheric Research, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria; Natural History Museum, Burgring 7, 1010 Vienna, Austria https://www.scopus.com/inward/record.uri?eid=2-s2.0-78650939968&doi=10.1130%2f2010.2465%2821%29&partnerID=40&md5=8d22d7c325bc4a147acc229b0b80bd6b cited By 12 L. Coney W.U. Reimold R.L. Gibson C. Koeberl P. Ogilvie article Liu2010909 The implementation of EarthScope, the deep exploration program in North American continent has become the focus of attention in the field of Earth Sciences. This paper gives a brief description of the background, scientific problems to be solved, observational approaches adopted,some research progresses of the EarthScope program in the fields such as seismic tomographic imaging, earth stress change, continental structure, topographic survey and so on. 2010 Chinese 10009515 Acta Geologica Sinica (English Edition) 84 909-926 Chinese Academy of Geological Sciences, Beijing, 100037, China 6 exploration; geological survey; imaging method; research program; tomography; topographic mapping, North America https://www.scopus.com/inward/record.uri?eid=2-s2.0-78649812321&partnerID=40&md5=1c58b446fd37cc06a5825e02ca662ee2 cited By 4 G. Liu S. Dong X. Chen Q. Zhou Z. Liu article Coney2010411 A petrographic and geochemical comparison of suevites from the LB-07A and LB-08A cores recovered during 2004 by the International Continental Scientific Drilling Program with suevites from outside of the crater rim of the Bosumtwi impact structure indicates contrasting mechanisms of formation for these respective impact breccias. The within-crater suevites form only a small part of the lithic impact breccia-dominated impactite crater fill, in contrast to the impactites from outside of the crater, which consist solely of suevite. The clasts of suevites from within the crater display relatively low levels of shock (for most material <45 GPa). The numbers of shocked quartz grains, as well as fragments of diaplectic glass of quartz and feldspar in suevites decrease with depth through the LB-07A core (maximum three sets of planar deformation features [PDFs]). In contrast, the out-of-crater suevites sampled north and south of the crater contain up to four PDF sets in quartz clasts, ballen cristobalite, and higher proportions of diaplectic glass than the within-crater suevites. In addition, the suevites from outside of the crater contain significantly more melt particles (18-37 vol%) than the within-crater suevites (<5 vol%). Melt fragment sizes in suevites from outside the crater are much larger than those from suevites within the crater (maximum 40 cm versus 1 cm). The currently known distribution of impactites outside of the crater would be consistent with a low-angle impact from the east. We propose that the within-crater suevites and polymict lithic breccias were emplaced either via slumping off the crater walls or lateral movement of some melted and much displaced target rock within the crater. Limited admixture of fallback material from the ejecta plume is evident in the uppermost impactite deposit encountered in core LB-05B. In contrast, the out-of-crater suevites formed by fallout from a laterally differentiated ejecta plume, which resulted in different clast populations to the north and south of the crater. © 2010 The Geological Society of America. All rights reserved. Article 2010 English 00721077 10.1130/2010.2465(21) Special Paper of the Geological Society of America 465 Geological Society of America 411 – 442 Ashanti; Ghana; Lake Bosumtwi; Feldspar; Glass; Quartz; Rocks; Silicate minerals; Continental scientific drillings; Crater formation; Impact structures; Lateral movement; Mechanisms of formation; Particle characteristics; Planar deformation; Shocked quartz; crater; geochemistry; impact structure; petrography; suevite; Meteor impacts https://www.scopus.com/inward/record.uri?eid=2-s2.0-78650939968&doi=10.1130%2f2010.2465%2821%29&partnerID=40&md5=8d22d7c325bc4a147acc229b0b80bd6b Cited by: 12 Louise Coney Wolf Uwe Reimold Roger L. Gibson Christian Koeberl Paula Ogilvie article Xu201035 Major ion concentrations were measured in lake water, river water, ground water, and rainfall water around the Lake Qinghai catchment. The dissolution of carbonate particles in dust has a strong impact on the chemical composition of rainfall as inferred from the Gibbs model and the ternary plots of the major ions. The chemical composition of the ground water can be divided into two groups, one influenced by river water and the other dominated by deeper aquifers. The chemical composition of lake water can be mainly ascribed to evaporation and crystallization. Total dissolved solid (TDS) of river waters during the wet periods is higher than during the dry periods. Calcium and bicarbonate are the dominant cations and anions of the river waters, and they have higher fractions during the wet periods than during the dry periods. Comparisons between (Mg2+ + Ca2+)/TZ+, (Mg2+ + Ca2+)/(Na+ + K+), HCO3-/Na+, and Cl-/Na+ suggest that the chemical composition of the river waters is mainly controlled by carbonate weathering and that the carbonate weathering is much stronger during the wet periods than during the dry periods. Seasonal melting may be one of the important factors that influence the seasonal variations of water chemistry of the rivers. © 2008 Elsevier Ltd and INQUA. Article 2010 English 10406182 10.1016/j.quaint.2008.11.001 Quaternary International 212 35 – 43 1 China; Qinghai; Qinghai Lake; Qinghai-Xizang Plateau; catchment; chemical composition; crystallization; evaporation; groundwater; lake water; rainwater; river water; water chemistry https://www.scopus.com/inward/record.uri?eid=2-s2.0-73649146587&doi=10.1016%2fj.quaint.2008.11.001&partnerID=40&md5=db685964283f8109f10069bd3b9656b2 Cited by: 90 Hai Xu Zhaohua Hou ZhiSheng An Xiaoyan Liu Jibao Dong article Bahlburg2010170 The crater fill units that were deposited during the terminal stages of the formation of the shallow marine Chicxulub crater in northern Yucatan were interpreted by some authors as products of a catastrophic resurge of water. This interpretation contrasts markedly with the dominant sand grain size &lt;300μm and the abundant small-scale current cross bedding structures indicative of low energy deposition. To solve this discrepancy we applied first principles of physical sedimentology in an analysis of grain size and sedimentary structures to determine current velocities and minimum water depths required to generate the observed sedimentary bedforms. We combine this approach with numerical modeling of crater formation in order to explore the dimensions of the ejecta ring wall being formed by a Chicxulub impactor in water depths of 1000m. We find that the ejecta wall reaches heights in the order of 1200m above sea floor and 200m above sea level. It thus prevented the resurge of water into the crater cavity and consequently also the subsequent formation of a collapse wave. The ring wall significantly retarded the refilling of the crater cavity with seawater, and refilling took place by permeation through and localized erosion of the ring wall. This resulted in low-energy currents with velocities between 1.5 and 0.18ms-1 slowly reentering the crater and depositing the cm-scale, low energy laminated and crossbedded sandy terminal impact deposits. © 2010 Elsevier B.V. 2010 10.1016/j.epsl.2010.03.037 Earth and Planetary Science Letters 295 170-176 Institut für Geologie und Paläontologie, Westfälische Wilhelms-Universität Münster, Corrensstrasse 24, 48149 Münster, Germany; Department of Geology and Geophysics, Texas AandM University, College Station, TX 77843, United States; Museum für Naturkunde, Leibniz Institute at the Humboldt Universität zu Berlin, Invalidenstr. 43, 10115 Berlin, Germany 1-2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-77953025410&doi=10.1016%2fj.epsl.2010.03.037&partnerID=40&md5=5a452f60f4880f277bdbe72423faac22 cited By 8 H. Bahlburg R. Weiss K. Wünnemann article Lin201082 To reveal details of stress perturbations associated with faults and fractures, we investigated the faults and large fractures accompanied by stress-induced borehole breakouts or drilling-induced tensile fractures in hole B of the Taiwan Chelungpu-fault Drilling Project (TCDP). Then, we determined the relationship between the faults and fractures and stress orientation changes. We identified faults and fractures from electrical images of the borehole wall obtained by downhole logging but also from photographs and descriptions of retrieved core samples, and measured the variations in the principal horizontal stress orientation ascertained from borehole breakouts observed on the electrical images in the vicinity of the faults and fractures. Identification of geological structures (faults, fractures, and lithologic boundaries) by electrical images only is difficult and may sometimes yield incorrect results. In a novel approach, therefore, we used both the electrical images and core photographs to identify geological structures. We found four patterns of stress orientation change, or no change, in the vicinity of faults and fractures in TCDP hole B: (i) abrupt (discontinuous) rotation in the vicinity of faults or fractures; (ii) gradual rotation; (iii) suppression of breakouts at faults, fractures, or lithologic boundaries; and (iv) no change in the stress orientation. We recognized stress fluctuations, that is, heterogeneous mesoscale (≥ 10 cm) stress distributions with respect to both stress orientation and magnitude. In addition, we found that stress state changes occurred frequently in the vicinity of faults, fractures, and lithologic boundaries. © 2009 Elsevier B.V. All rights reserved. 2010 English 00401951 10.1016/j.tecto.2009.06.020 Tectonophysics 482 82-91 Kochi Institute for Core Sample Research, Japan Agency for Marine-Earth Science and Technology, 200 Monobe-otsu, Nankoku, Kochi, 783-8502, Japan; Kochi Institute for Core Sample Research, Japan Agency for Marine-Earth Science and Technology, Japan; Institute of Geophysics, National Central University, Chung-Li, 32054, Taiwan; Department of Materials Science and Engineering, the Geological Engineering Program, University of Wisconsin, Madison, WI 53706, United States; Graduate School of Science, Osaka University, Osaka, 560-0043, Japan 1-4 Borehole wall; Downholes; Drilling projects; Drilling-induced tensile fractures; Electrical images; Fracture stress; Geological structures; Horizontal stress; Mesoscale; Principal stress; Stress distribution; Stress fluctuations; Stress orientations; Stress perturbations; Stress state; Stress-induced, Drilling; Fracture; Photography; Rotation; Stress concentration, Boreholes, borehole breakout; core analysis; drilling; electrical method; fault; fracture; image analysis; spatial variation; stress analysis; stress field; tensile stress, Chelungpu Fault Zone; Taiwan https://www.scopus.com/inward/record.uri?eid=2-s2.0-76049112276&doi=10.1016%2fj.tecto.2009.06.020&partnerID=40&md5=35a54b66f2a8f85269af20fac0e88d9a cited By 67 W. Lin E.-C. Yeh J.-H. Hung B. Haimson T. Hirono article Holtvoeth20103473 Organic matter preserved in Lake Ohrid sediments originates from aquatic and terrestrial sources. Its variable composition reflects climate-controlled changes in the lake basin's hydrology and related organic matter export, i.e. changes in primary productivity, terrestrial plant matter input and soil erosion. Here, we present first results from lipid biomarker investigations of Lake Ohrid sediments from two near-shore settings: site Lz1120 near the southern shore, with low-lying lands nearby and probably influenced by river discharge, and site Co1202 which is close to the steep eastern slopes. Variable proportions of terrestrial n-alkanoic acids and n-alkanols as well as compositional changes of ‰-hydroxy acids document differences in soil organic matter supply between the sites and during different climate stages (glacial, Holocene, 8.2 ka cooling event). Changes in the vegetation cover are suggested by changes in the dominant chain length of terrestrial n-alkanols. Effective microbial degradation of labile organic matter and in situ contribution of organic matter derived from the microbes themselves are both evident in the sediments. We found evidence for anoxic conditions within the photic zone by detecting epicholestanol and tetrahymanol from sulphur-oxidising phototrophic bacteria and bacterivorous ciliates and for the influence of a settled human community from the occurrence of coprostanol, a biomarker for human and animal faeces (pigs, sheep, goats), in an early Holocene sample. This study illustrates the potential of lipid biomarkers for future environmental reconstructions using one of Europe's oldest continental climate archives, Lake Ohrid. © Author(s) 2010. Article 2010 English 17264189 10.5194/bg-7-3473-2010 Biogeosciences 7 3473 – 3489 11 Lake Ohrid; Animalia; Capra hircus; Ciliophora; Ovis aries; Photobacteria; Suidae; anoxic conditions; aquatic environment; bacterium; biodegradation; biomarker; climate change; glacial deposit; Holocene; hydrology; lacustrine deposit; lipid; organic acid; organic matter; paleoenvironment; primary production; river discharge; soil erosion; soil organic matter; terrestrial environment; vegetation cover https://www.scopus.com/inward/record.uri?eid=2-s2.0-78349266512&doi=10.5194%2fbg-7-3473-2010&partnerID=40&md5=34f8f5a52ab67d38cc2ebba787a0f6e6 Cited by: 47; All Open Access, Gold Open Access, Green Open Access J. Holtvoeth H. Vogel B. Wagner G.A. Wolff article Mueller20101220 Long sediment cores were collected in spring 2006 from Lake Petén Itzá, northern Guatemala, in water depths ranging from 30 to 150 m, as part of an International Continental Scientific Drilling Program project. The sediment records from deep water consist mainly of alternating clay, gypsum and carbonate units and, in at least two drill sites, extend back >200 kyr. Most of the lithostratigraphic units are traceable throughout the basin along seismic reflections that serve as seismic stratigraphic boundaries and suggest that the lithostratigraphy can be used to infer regional palaeoenvironmental changes. A revised seismic stratigraphy was established on the basis of integrated lithological and seismic reflection data from the basin. From ca 200 to ca 85 ka, sediments are dominated by carbonate-clay silt, often interbedded with sandy turbidites, indicating a sediment regime dominated by detrital sedimentation in a relatively humid climate. At ca 85 ka, an exposure horizon consisting of gravels, coarse sand and terrestrial gastropods marks a lake lowstand or partial basin desiccation, indicating dry climate conditions. From ca 85 to ca 48 ka, transgressive carbonate-clay sediments, overlain by deep-water clays, suggest a lake level rise and subsequent stabilization at high stage. From ca 48 ka to present, the lithology is characterized by alternating clay and gypsum units. Gypsum deposition correlates with Heinrich Events (i.e. dry climate), whereas clay units coincide with more humid interstadials. © 2010 The Authors. Journal compilation © 2010 International Association of Sedimentologists. Article 2010 English 13653091 10.1111/j.1365-3091.2009.01144.x Sedimentology 57 1220 – 1245 5 Guatemala [Central America]; Lake Peten Itza; Peten; Gastropoda; Anoxic sediments; Carbonation; Climatology; Core drilling; Deepwater drilling; Drills; Gypsum; Lakes; Lithology; Offshore oil wells; Sedimentology; Seismic waves; Seismology; Guatemala; Lake level changes; Lake sediments; Palaeoclimatology; Seismic stratigraphy; climate conditions; deep drilling; deposition; environmental change; Heinrich event; lacustrine deposit; lake level; lithostratigraphy; paleoclimate; paleoenvironment; Quaternary; sediment core; sedimentation; seismic reflection; seismic stratigraphy; Stratigraphy https://www.scopus.com/inward/record.uri?eid=2-s2.0-77955244122&doi=10.1111%2fj.1365-3091.2009.01144.x&partnerID=40&md5=a8a71906e9f39b8c9df5e45ec5da9a39 Cited by: 34; All Open Access, Green Open Access Andreas D. Mueller Flavio S. Anselmetti Daniel Ariztegui Mark Brenner David A. Hodell Jason H. Curtis Jaime Escobar Adrian Gilli Dustin A. Grzesik Thomas P. Guilderson Steffen Kutterolf Michael Plötze article McGarr20103250 Laboratory stick-slip friction experiments indicate that peak slip rates increase with the stresses loading the fault to cause rupture. If this applies also to earthquake fault zones, then the analysis of rupture processes is simplified inasmuch as the slip rates depend only on the local yield stress and are independent of factors specific to a particular event, including the distribution of slip in space and time. We test this hypothesis by first using it to develop an expression for radiated energy that depends primarily on the seismic moment and the maximum slip rate. From laboratory results, the maximum slip rate for any crustal earthquake, as well as various stress parameters including the yield stress, can be determined based on its seismic moment and the maximum slip within its rupture zone. After finding that our new equation for radiated energy works well for laboratory stick-slip friction experiments, we used it to estimate radiated energies for five earthquakes with magnitudes near 2 that were induced in a deep gold mine, an M 2.1 repeating earthquake near the San Andreas Fault Observatory at Depth (SAFOD) site and seven major earthquakes in California and found good agreement with energies estimated independently from spectra of local and regional ground-motion data. Estimates of yield stress for the earthquakes in our study range from 12 MPa to 122 MPa with a median of 64 MPa. The lowest value was estimated for the 2004 M 6 Parkfield, California, earthquake whereas the nearby M 2.1 repeating earthquake, as recorded in the SAFOD pilot hole, showed a more typical yield stress of 64 MPa. 2010 English 00371106 10.1785/0120100043 Bulletin of the Seismological Society of America 100 3250-3260 U.S. Geological Survey, MS 977, 345 Middlefield Rd, Menlo Park, CA 94025, United States; Department of Earth Sciences, University of New Hampshire, Durham, NH 03824, United States 6 California; Crustal earthquakes; Deep gold mines; Earthquake fault; Earthquake rupture; Ground-motion; Maximum slip; Pilot holes; Radiated energies; Repeating earthquake; Rupture process; Rupture zone; San Andreas Fault; Seismic moment; Slip rates; Space and time; Stick-slip friction; Stress parameter, Earthquakes; Experiments; Friction; Gold mines; Gravitational effects; Laboratories; Slip forming; Tectonics, Yield stress, earthquake magnitude; earthquake rupture; fault zone; ground motion; seismic moment; slip rate https://www.scopus.com/inward/record.uri?eid=2-s2.0-78650125662&doi=10.1785%2f0120100043&partnerID=40&md5=93ba0f7ac73ac8f256ca0092937df571 cited By 13 A. McGarr J.B. Fletcher M. Boettcher N. Beeler J. Boatwright article Gibson2010 2010 English 00721077 10.1130/2010.2465(00) Special Paper of the Geological Society of America 465 vii-xii Impact Cratering Research Group, School of Geosciences, University of the Witwatersrand, Johannesburg 2050, South Africa; Museum für Naturkunde, Leibniz Institute, Humboldt University Berlin, Invalidenstrasse 43, 10115 Berlin, Germany cratering; impact structure; literature review; planetary evolution https://www.scopus.com/inward/record.uri?eid=2-s2.0-78650934522&doi=10.1130%2f2010.2465%2800%29&partnerID=40&md5=732258c8a4600122b1358cfbbfe0af55 cited By 1 R.L. Gibson W.U. Reimold article Haimson201065 The paper describes the computation of the maximum horizontal stress (σH) magnitude in the vicinity of the Chelungpu Fault, Taiwan, host of the slip zone during the Chi-Chi earthquake (Mw 7.6; 1999). The scientific hole B intercepts the Chelungpu Fault at 1136 m. At the depths of logged breakouts (940-1310 m), the vertical stress (σv) as estimated from density logs increases linearly with depth from 22 to 31 MPa. A series of leak-off tests yielded two reliable shut-in pressures, 23.7 MPa at 1085 m and 29.8 MPa at 1279 m, which are lower than the estimated σv, albeit by only 2.1 and 0.6 MPa, respectively. In our analysis the shut-in pressures were considered to represent estimates of the least horizontal principal stresses (σh) at the respective depths, and consequently the test-induced fractures were assumed to have been vertical. Principal stress directions had been previously determined by others (105°-155° for the maximum horizontal stress, σH, except in the immediate vicinity of the Chelungpu Fault). The contribution of this paper is the estimation of the σH magnitude by considering that the state of stress at the points of intersection between breakout and borehole wall is in a state of limit equilibrium with the true triaxial strength criterion. The resulting σH in the range of logged breakouts increases with depth from 55 MPa at 940 m to 59 MPa at 1310 m. Thus, the estimated state of stress prevailing across the Chelungpu Fault is compatible with strike-slip, but marginally also with thrust faulting. However, the likelihood that the shut-in pressures actually represent σv magnitudes, and that the leak-off test-induced fractures were sub-horizontal, cannot be ignored. In that case the state of stress would clearly favor thrust faulting. © 2009 Elsevier B.V. All rights reserved. 2010 English 00401951 10.1016/j.tecto.2009.05.016 Tectonophysics 482 65-72 Department of Materials Science and Engineering, the Geological Engineering Program, University of Wisconsin, 1609 University Avenue, Madison, WI 53706, United States; Kochi Institute for Core Sample Research, Japan Agency for Marine-Earth Science and Technology, 200 Monobe-otsu, Nankoku, Kochi, 783-8502, Japan; Institute of Geophysics, National Central University, Jhongli, Taiwan; Department of Geoscience, National Taiwan University, Taipei, Taiwan 1-4 Borehole wall; ChiChi earthquake; Density log; Estimated state; Horizontal stress; Insitu stress; Leak-off tests; Limit equilibrium; Principal stress; Shut-in pressure; Slip zones; State of stress; Strength criteria; Thrust faulting; True triaxial strength; True triaxial strength criteria; Vertical stress, Asphalt pavements; Blowouts; Electromagnetic logging; Fracture; Instruments; Maximum likelihood estimation; Radioactivity logging; Stress measurement, Boreholes, borehole breakout; fault zone; in situ stress; integrated approach; pressure effect; stress analysis; strike-slip fault; thrust fault; triaxial test; well logging, Chelungpu Fault Zone; Taiwan https://www.scopus.com/inward/record.uri?eid=2-s2.0-76049106322&doi=10.1016%2fj.tecto.2009.05.016&partnerID=40&md5=7ac5416ff38f9f006d05723c15e86631 cited By 41 B. Haimson W. Lin H. Oku J.-H. Hung S.-R. Song article Edwards2010319 Two cores at the outer margin of the Chesapeake Bay impact structure show significant structural and depositional variations that illuminate its history. Detailed stratigraphy of the Watkins School core reveals that this site is outside the disruption boundary of the crater with respect to its lower part (nonmarine Cretaceous Potomac Formation), but just inside the boundary with respect to its upper part (Exmore Formation and a succession of upper Eocene to Pleistocene postimpact deposits). The site of the U.S. Geological Survey-National Aeronautics and Space Administration Langley core, 6.4 km to the east, lies wholly within the annular trough of the crater. The Potomac Formation in the Watkins School core is not noticeably impact disrupted. The lower part of crater unit A in the Langley core represents stratigraphically lower, but similarly undeformed material. The Exmore Formation is only 7.8 m thick in the Watkins School core, but it is over 200 m thick in the Langley core, where it contains blocks up to 24 m in intersected diameter. The upper part of the Exmore Formation in the two cores is a polymict diamicton with a stratified zone at the top. The postimpact sedimentary units in the two cores have similar late Eocene and late Miocene depositional histories and contrasting Oligocene, early Miocene, and middle Miocene histories. A paleochannel of the James River removed Pliocene deposits at the Watkins School site, to be filled later with thick Pleistocene deposits. At the Langley site, a thick Pliocene and thinner Pleistocene record is preserved. © 2010 The Geological Society of America. All rights reserved. 2010 English 00721077 10.1130/2010.2465(19) Special Paper of the Geological Society of America 465 Geological Society of America 319-393 U.S. Geological Survey, 926A National Center, Reston, VA 20192, United States Deposits; NASA; Stratigraphy, Chesapeake bay impact structures; Early Miocene; Middle Miocene; Pleistocene deposits; Pliocene deposits; Sedimentary units; U.s. geological surveys; Undeformed materials, Meteor impacts, crater; depositional sequence; impact structure; Miocene; paleochannel; Pleistocene; stratigraphy, Chesapeake Bay; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-78650928489&doi=10.1130%2f2010.2465%2819%29&partnerID=40&md5=a1aa225822fa339bee71ddfccd266633 cited By 7 L.E. Edwards D.S. Powars J.W. Horton Jr. G.S. Gohn J.M. Self-Trail R.J. Litwin article Kaden2010 Changes in the hydrological regime of the saline closed basin Lake Van, a large, deep lake in eastern Turkey, resulted in a lake level increase by about 2 m between 1988 and 1995, followed by a 1.5 m decrease until 2003 and a relatively constant lake level thereafter. Based on measurements of transient tracers (sulfur hexafluoride, CFC-12, 3H, 3He, 4He, Ne), dissolved oxygen, light transmission, conductivity- temperature-depth profiles, and thermistor data, we investigate the implications associated with lake level fluctuations for deep-water renewal and oxygenation. Our data suggest that deep-water renewal was significantly reduced in Lake Van between 1990 and 2005. This change in mixing conditions resulted in the formation of a more than 100 m thick anoxic deep-water body below 325 m depth. Apparently, the freshwater inflows responsible for the lake level rise between 1988 and 1995 decreased the salinity of the surface water sufficiently that the generation of density plumes during winter cooling was substantially reduced compared to that in the years before the lake level rise. Significant renewal and oxygenation of the deep water did not occur until at least 2005, although by 2003 the lake level was back to almost the same level as in 1988. This study suggests that short-term changes in the hydrological regime, resulting in lake level changes of a couple of meters, can lead to significant and long-lasting changes in deep-water renewal and oxic conditions in deep saline lakes. Copyright © 2010 by the American Geophysical Union. 2010 English 00431397 10.1029/2009WR008555 Water Resources Research 46 Department of Environmental Physics, Limnological Institute, University of Konstanz, Mainaustr. 252, D-78464 Konstanz, Germany; Department of Environmental Science, University of Koblenz-Landau, Fortstr. 7, D-76829 Landau, Germany; Department of Water Resources and Drinking Water, Swiss Federal Institute for Environmental Science and Technology (EAWAG), Überlandstr. 133, CH-8600 Dübendorf, Switzerland; Department of Isotope Geochemistry and Mineral Resources, Swiss Federal Institute of Technology, Zürich, Switzerland; Department of Anthropology, Yüzuncü Yil University, Zeve Campus, 65080 Van, Turkey 11 Conductivity temperature depths; Deep-water renewals; Deepwater; Eastern Turkey; Freshwater inflow; Hydrological regime; Lake level fluctuations; Lake levels; Long lasting; Mixing conditions; Oxic conditions; Saline lake; Transient tracers; Winter cooling, Biochemical oxygen demand; Dissolved oxygen; Light transmission; Neon; Oxygenation; Oxygenators; Pumps; Saline water; Sulfur; Sulfur hexafluoride, Lakes, deep water; dissolved oxygen; freshwater input; hydrological regime; inflow; lake level; oxic conditions; oxygenation; saline lake; salinity; surface water; tracer, Lake Van; Turkey https://www.scopus.com/inward/record.uri?eid=2-s2.0-78249269826&doi=10.1029%2f2009WR008555&partnerID=40&md5=f25ae4fbac03ebd760cce52c548ed2e2 cited By 48 H. Kaden F. Peeters A. Lorke R. Kipfer Y. Tomonaga M. Karabiyikoglu article Leng20103109 Here we present stable isotope data from three sediment records from lakes that lie along the Macedonian-Albanian border (Lake Prespa: 1 core, and Lake Ohrid: 2 cores). The records only overlap for the last 40 kyr, although the longest record contains the MIS 5/6 transition (Lake Ohrid). The sedimentary characteristics of both lakes differ significantly between the glacial and interglacial phases. At the end of MIS 6 Lake Ohrid's water level was low (high δ18Ocalcite) and, although productivity was increasing (high calcite content), the carbon supply was mainly from inorganic catchment rock sources (high δ13Ccarb). During the last interglacial, calcite and TOC production and preservation increased, progressively lower δ18Ocalcite suggest increase in humidity and lake levels until around 115 ka. During ca. 80 ka to 11 ka the lake records suggest cold conditions as indicated by negligible calcite precipitation and low organic matter content. In Lake Ohrid, δ13Corg are complacent; in contrast, Lake Prespa shows consistently higher δ13Corg suggesting a low oxidation of 13C-depleted organic matter in agreement with a general deterioration of climate conditions during the glacial. From 15 ka to the onset of the Holocene, calcite and TOC begin to increase, suggesting lake levels were probably low (high δ18Ocalcite). In the Holocene (11 ka to present) enhanced productivity is manifested by high calcite and organic matter content. All three cores show an early Holocene characterised by low δ18Ocalcite, apart from the very early Holocene phase in Prespa where the lowest δ18Ocalcite occurs at ca. 7.5 ka, suggesting a phase of higher lake level only in (the more sensitive) Lake Prespa. From 6 ka, δ18Ocalcite suggest progressive aridification, in agreement with many other records in the Mediterranean, although the uppermost sediments in one core records low δ18Ocalcite which we interpret as a result of human activity. Overall, the isotope data present here confirm that these two big lakes have captured the large scale, low frequency palaeoclimate variation that is seen in Mediterranean lakes, although in detail there is much palaeoclimate information that could be gained, especially small scale, high frequency differences between this region and the Mediterranean. © 2010 Author(s). Article 2010 English 17264189 10.5194/bg-7-3109-2010 Biogeosciences 7 3109 – 3122 10 Lake Mikri Prespa; Lake Ohrid; aridification; calcite; catchment; core analysis; geological record; Holocene; human activity; humidity; Mediterranean environment; paleoclimate; paleoenvironment; reconstruction; sediment core; stable isotope; total organic carbon; water level https://www.scopus.com/inward/record.uri?eid=2-s2.0-77958055757&doi=10.5194%2fbg-7-3109-2010&partnerID=40&md5=127aafd8b13490b471b1ad88cf342083 Cited by: 60; All Open Access, Gold Open Access, Green Open Access M.J. Leng I. Baneschi G. Zanchetta C.N. Jex B. Wagner H. Vogel article Jin2010151 Water level and chemistry of Lake Qinghai are sensitive to climate changes and are important for paleoclimatic implications. An accurate understanding of hydrological and chemical budgets is crucial for quantifying geochemical proxies and carbon cycle. Published results of water budget are firstly reviewed in this paper. Chemical budget and residence time of major dissolved constituents in the lake are estimated using reliable water budget and newly obtained data for seasonal water chemistry. The results indicate that carbonate weathering is the most important riverine process, resulting in dominance of Ca2+ and DIC for river waters and groundwater. Groundwater contribution to major dissolved constituents is relatively small (4.2 ± 0.5%). Wet atmospheric deposition contributes annually 7.4-44.0% soluble flux to the lake, resulting from eolian dust throughout the seasons. Estimates of chemical budget further suggest that (1) the Buha-type water dominates the chemical components of the lake water, (2) Na+, Cl-, Mg2+, and K+ in lake water are enriched owing to their conservative behaviors, and (3) precipitation of authigenic carbonates (low-Mg calcite, aragonite, and dolomite) transits quickly dissolved Ca2+ into the bottom sediments of the lake, resulting in very low Ca2+ in the lake water. Therefore, authigenic carbonates in the sediments hold potential information on the relative contribution of different solute inputs to the lake and the lake chemistry in the past. © 2009 Elsevier Ltd and INQUA. Article 2010 English 10406182 10.1016/j.quaint.2009.11.024 Quaternary International 218 151 – 156 1-2 China; Qinghai; Qinghai Lake; carbon cycle; carbonate; paleohydrology; residence time; solute; water budget; water chemistry; water level; weathering; wet deposition https://www.scopus.com/inward/record.uri?eid=2-s2.0-77952549606&doi=10.1016%2fj.quaint.2009.11.024&partnerID=40&md5=5a54daf69436718e730f297e67a84ee1 Cited by: 55 Zhangdong Jin Chen-Feng You Yi Wang Yuewei Shi article Rosén2010247 We demonstrate the use of Fourier transform infrared spectroscopy (FTIRS) to make quantitative measures of total organic carbon (TOC), total inorganic carbon (TIC) and biogenic silica (BSi)concentrations in sediment. FTIRS is a fast and cost-effective technique and only small sediment samples are needed (0.01 g). Statistically significant models were developed using sediment samples from northern Sweden and were applied to sediment records from Sweden, northeast Siberia and Macedonia. The correlation between FTIRS-inferred values and amounts of biogeochemical constituents assessed conventionally varied between r = 0.84-0.99 for TOC, r = 0.85-0.99 for TIC, and r = 0.68-0.94 for BSi. Because FTIR spectra contain information on a large number of both inorganic and organic components, there is great potential for FTIRS to become an important tool in paleolimnology. © Springer Science+Business Media B.V. 2009. 2010 English 09212728 10.1007/s10933-009-9329-4 Journal of Paleolimnology 43 247-259 Climate Impacts Research Centre (CIRC), Umeå University, 98107 Abisko, Sweden; Institute for Geology and Mineralogy, University of Cologne, Zuelpicher Str. 49a, 50674 Cologne, Germany; GeoBiosphere Science Centre, Quaternary Sciences, Lund University, Sölvegatan. 12, 223 62 Lund, Sweden; Department of Chemistry, Umeå University, 90187 Umeå, Sweden; Freshwater Biological Laboratory, Department of Biology, University of Copenhagen, Helsingørsgade 51, 3400 Hillerød, Denmark 2 biogenic deposit; biogeochemistry; concentration (composition); correlation; FTIR spectroscopy; inorganic carbon; lacustrine deposit; paleolimnology; quantitative analysis; sediment chemistry; silica; total organic carbon, Greece; Macedonia [Greece]; Siberia; Sweden https://www.scopus.com/inward/record.uri?eid=2-s2.0-77956302739&doi=10.1007%2fs10933-009-9329-4&partnerID=40&md5=b3ac293c85318db762eb2fedcda9bfeb cited By 73 P. Rosen H. Vogel L. Cunningham N. Reuss D.J. Conley P. Persson article Wagner20103187 Lakes Prespa and Ohrid, in the Balkan region, are considered to be amongst the oldest lakes in Europe. Both lakes are hydraulically connected via karst aquifers. From Lake Ohrid, several sediment cores up to 15 m long have been studied over the last few years. Here, we document the first long sediment record from nearby Lake Prespa to clarify the influence of Lake Prespa on Lake Ohrid and the environmental history of the region. Radiocarbon dating and dated tephra layers provide robust age control and indicate that the 10.5 m long sediment record from Lake Prespa reaches back to 48 ka. Glacial sedimentation is characterized by low organic matter content and absence of carbonates in the sediments, which indicate oligotrophic conditions in both lakes. Holocene sedimentation is characterized by particularly high carbonate content in Lake Ohrid and by particularly high organic matter content in Lake Prespa, which indicates a shift towards more mesotrophic conditions in the latter. Long-term environmental change and short-term events, such as related to the Heinrich events during the Pleistocene or the 8.2 ka cooling event during the Holocene, are well recorded in both lakes, but are only evident in certain proxies. The comparison of the sediment cores from both lakes indicates that environmental change affects particularly the trophic state of Lake Prespa due to its lower volume and water depth. © Author(s) 2010. Article 2010 English 17264189 10.5194/bg-7-3187-2010 Biogeosciences 7 3187 – 3198 10 Balkan; Lake Mikri Prespa; Lake Ohrid; Turkmenistan; carbonate; core analysis; environmental change; glacial deposit; Heinrich event; Holocene; karst hydrology; lacustrine deposit; organic matter; paleoenvironment; paleolimnology; Pleistocene; radiocarbon dating; sedimentation rate; tephra; trophic status https://www.scopus.com/inward/record.uri?eid=2-s2.0-77958613334&doi=10.5194%2fbg-7-3187-2010&partnerID=40&md5=560f1168a1f72e6aa51c82a8da09b671 Cited by: 59; All Open Access, Gold Open Access, Green Open Access B. Wagner H. Vogel G. Zanchetta R. Sulpizio article Gondwe20101 The Yucatan Peninsula is one of the world's largest karstic aquifer systems. It is the sole freshwater source for human users and ecosystems. The region hosts internationally important groundwater-dependent ecosystems (GDEs) in the 5280km2 Sian Ka'an Biosphere Reserve. The GDEs are threatened by increasing groundwater abstractions and risks of pollution. Hydrogeological exploration work is needed as basis for sound groundwater management. A multidisciplinary approach was used to study this data-scarce region. Geochemical data and phreatic surface measurements showed distinct hydrogeological units in the groundwater catchment of Sian Ka'an. The hilly southwestern areas had a low hydraulic permeability, likely caused by a geology containing gypsum, whereas the transition zone and flat areas in the east and north had a high permeability. In the latter areas, the fresh groundwater could be described by a Dupuit-Ghyben-Herzberg lens. Geophysical borehole logging and time-domain electromagnetic soundings identified a shallow, low-resistive and high-gamma-radiation layer present throughout the hilly area and transition zone. Its thickness was 3-8m, apparent conductivity was 200-800mS/m and natural gamma-radiation about 80 counts pr. second. The layer is proposed to be ejecta from the Chicxulub impact (Cretaceous/Paleogene boundary). Spatial estimates of recharge were calculated from MODIS imagery using the 'triangle method'. Average recharge constituted 17% of mean annual precipitation in the study area. Recharge was greatest in the hilly area and towards Valladolid. Near the coast, average actual evapotranspiration exceeded annual precipitation. The multidisciplinary approach used in this study is applicable to other catchment-scale studies. © 2010 Elsevier B.V. 2010 10.1016/j.jhydrol.2010.04.044 Journal of Hydrology 389 1-17 Department of Environmental Engineering, Technical University of Denmark, Miljoevej,Building 113, DK-2800 Kgs. Lyngby, Denmark; Geological Survey of Denmark and Greenland (GEUS), Oester Voldgade 10, DK-1350 Copenhagen, Denmark; Instituto de Geofísica, Universidad Nacinal Autónoma de México, Cd. Universitaria, México DF 04510, Mexico; Centro para el Estudio del Agua, CICY-Quintana Roo, Calle 8, Lote 1, No. 39, Manzana 20 SM 64, Cancún, Quintana Roo 77500, Mexico; Amigos de Sian Ka'an, Calle Fuego No. 2, Manzana 10 SM 4, Cancún, Quintana Roo 77500, Mexico 1-2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-77954386651&doi=10.1016%2fj.jhydrol.2010.04.044&partnerID=40&md5=64e397cb7dd9ae790c707d3354602289 cited By 72 B.R.N. Gondwe S. Lerer S. Stisen L. Marín M. Rebolledo-Vieyra G. Merediz-Alonso P. Bauer-Gottwein article Tembe2010 2010 English 21699313 10.1029/2009jb000818 Journal of Geophysical Research: Solid Earth 115 Blackwell Publishing Ltd 3 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84904676438&doi=10.1029%2f2009jb000818&partnerID=40&md5=543066649e2677221dfb3976f367b770 cited By 4 S. Tembe D. Lockner T.-F. Wong article Hoffmann20103377 Lake Ohrid Basin is a graben structure situated in the Dinarides at the border of the Former Yugoslavian Republic of Macedonia (FYROM) and Albania. It hosts one of the oldest lakes in Europe and is characterized by a basin and range-like geological setting together with the halfgraben basins of Korca, Erseka and Debar. The basin is surrounded by Paleozoic metamorphics in the northeast and north and Mesozoic ultramafic, carbonatic and magmatic rocks in the east, northwest, west and south. Paleocene to Pliocene units are present in the southwest. With the basin development, Neogene sediments from Pliocene to recent deposited in the lows. There are three major deformation phases: (A) NWĝ€"SE shortening from Late Cretaceous to Miocene; (B) uplift and diminishing compression during Messinian ĝ€" Pliocene; (C) vertical uplift and (N)Eĝ€"(S)W extension from Pliocene to recent led to the basin formation. Neotectonic activity of the study area concentrates on Nĝ€"S trending normal faults that bound the Ohrid Basin eastwards and westwards. Seismic activity with moderate to strong events is documented during the last 2000 yrs; the seismic hazard level is among the highest in Albania and Macedonia. Activity of the youngest faults is evidenced by earthquake data and field observations. Morphotectonic features like fault scarps, a stepped series of active normal faults, deformed paleosols, a wind gap and fault-related hydrothermal activity are preserved around Lake Ohrid and allow delineating the tectonic history. It is shown that the Lake Ohrid Basin can be characterized as a seismogenic landscape. This paper presents a tectonic history of the Lake Ohrid Basin and describes tectonic features that are preserved in the recent landscape. The analysis of morphotectonic features is used to derive the deformation history. The stratigraphy of the area is summarized and concentrates on the main units. © 2010 Author(s). Article 2010 English 17264189 10.5194/bg-7-3377-2010 Biogeosciences 7 3377 – 3386 10 Albania; Lake Ohrid; Macedonia [Southern Europe]; data set; hydrothermal activity; lake evolution; landscape; magmatism; metamorphism; Neogene; neotectonics; observational method; Paleozoic; seismic anisotropy; seismic hazard; stratigraphy; uplift https://www.scopus.com/inward/record.uri?eid=2-s2.0-79960572977&doi=10.5194%2fbg-7-3377-2010&partnerID=40&md5=14bcb177358b62eb56df8de11692eafd Cited by: 38; All Open Access, Gold Open Access, Green Open Access N. Hoffmann K. Reicherter T. Fernández-Steeger C. Grützner article Skinner201018 The science program of the Iceland Deep Drilling Project (IDDP) requested that as much coring as possible should be done in the transition zone to supercritical and inside the supercritical zone in the depth interval 2,400-4,500m. The coring system selected is of conventional design, non-wireline with a 184.15mm OD and capable of collection of a 101.6mm diameter core using a 215.9mm OD core bit. The effective cooling is attributed to a top drive being employed that allows circulation while tripping in or out, except for the very short time when a new drill pipe connection is being made. The core barrels were made by Rok-Max Drilling Tools Ltd and the core bits were made by GeoGem Ltd, both UK companies with a good track record in making specialist coring equipment. The cored section consisted of a hyaloclastite breccia, thoroughly altered to greenschist facies mineralogy. 2010 English 09693769 Geodrilling International 18-22 162 https://www.scopus.com/inward/record.uri?eid=2-s2.0-77952928408&partnerID=40&md5=89ca12faec73abe89148aa026be88691 cited By 3 A. Skinner P. Bowers S. Pórhallsson G.O. Frioleifsson H. Guomundsson conference Enkin2010576 Natural gas hydrate reservoirs are hosted in heterogeneous sediments having variable pore fluid salinity. Questions concerning GH formation, detection and production are being addressed and measured in real time with simple laboratory apparatus. Our vessel is pressurized with methane and monitored with individually calibrated pressure transducers and thermistors. The silt or sand pack is assembled using uniform grain size layers containing ∼20% by weight of pore fluids. This results in mixed wettability, with pendant water and initial partial gas saturation. Sand packs consisting of silica silts, sands, and charcoal were selected to emulate the dominant lithofacies observed in the Mallik gas hydrate reservoir. Fluids range from distilled-water to 37ppt salinity. A central needle probe permits the measurements of electromagnetic signals across the specimen. Formation of GH alters the bulk dielectric constant of the mixture, through the conversion of water to gas hydrate crystals and or ice. The infilling of primary porosity by gas hydrate or water ice tends to reduce permeability and increase electrical resistivity, while the expulsion of solutes by hydrate or ice formation decreases resistivity by building a salt bridge along alternate permeability paths. Four methods monitored GH formation and dissociation: 1) Deposition or evolution of gas derived from measurement of the ambient pressure and temperature; 2) Calorimetric measurements of latent heat production by exothermic crystallization and consumption by endothermic dissociation; 3) Time-Domain Reflectometry (TDR) measurement of the velocity of electromagnetic signal propagation and reflections at boundaries in the sand pack; 4) Electrical Impedance Spectroscopy (EIS), a frequency domain method permitting direct measurement of the resistance and capacitance spectra. Improvements in real time digital monitoring and data analysis have made possible the recognition of TDR reflections previously considered unattainable in the presence of conducting fluids. The independent monitoring methods, with their various temporal and spatial sensitivities, capture the intricate details of GH formation and dissociation as a time series. In more porous and permeable beds, GH formation as evidenced by a coherent pressure drop and thermal pulse precedes the increase in electrical conductivity and dielectric constant. These results are interpreted to be the result of a diffusive pulse of solute exclusion from the GH-bearing layer into neighbouring sediment. Measurable EM effects suggest that borehole EIS, with lower frequency and greater penetration than TDR, may be effective for monitoring the variable position of GH-Methane interfaces during GH production tests. ©Her Majesty the Queen in Right of Canada 2010. 2010 English 9781617820427 10.2118/136900-ms Society of Petroleum Engineers - Canadian Unconventional Resources and International Petroleum Conference 2010 1 Society of Petroleum Engineers 576-589 Geological Survey of Canada, Canada; Camosun College, Canada; University of Victoria, Canada; University of Toronto, Canada Charcoal; Dissociation; Electric conductivity; Frequency domain analysis; Gases; Gasoline; Heat resistance; Hydration; Ice; Methane; Natural gasoline plants; Resource valuation; Sand; Sediments; Silica; Silt; Time domain analysis, Calorimetric measurements; Electrical impedance spectroscopy; Exothermic crystallization; Frequency-domain methods; Heterogeneous sediments; Natural gas hydrate reservoir; Temporal and spatial sensitivity; Time domain reflectometry, Gas hydrates https://www.scopus.com/inward/record.uri?eid=2-s2.0-79952970129&doi=10.2118%2f136900-ms&partnerID=40&md5=3462f15689a42f6aa95eeaca1c5a297b cited By 1 R.J. Enkin T.S. Hamilton J.F. Wright M. Kilduff D.J.W. Bild-Enkin article Wu2010343 Seismic guided wave dispersion can be used to image fault-zone structure at seismogenic depth. A two-station differential group velocity technique previously used for surface waves was adapted to solve for local fault-zone structure between two stations. This method was extended to solve for fault-zone structure between two earthquakes using differential group arrival times at a single station. The method was tested with finite-difference synthetic data for an inhomogeneous fault, as well as with a pair of shallow earthquakes recorded in the San Andreas Fault Observatory at Depth (SAFOD) borehole station. Results from a pair of deep earthquakes recorded in the SAFOD borehole station indicate that the low-velocity waveguide of the San Andreas Fault extends to >10 km depth. The waveguide at 10-12 km depth is 120-190 m wide and the velocity contrast is >20 per cent, similar to the values in the shallow subsurface. Multiple earthquakes and receivers could be used to map fault zone structure at seismogenic depth as a function of depth and strike. © 2010 The Authors Journal compilation © 2010 RAS. 2010 English 0956540X 10.1111/j.1365-246X.2010.04612.x Geophysical Journal International 182 343-354 Department of Geosciences, Virginia Tech, 4044 Derring Hall, Blacksburg, VA 24061, United States 1 arrival time; fault zone; finite difference method; image analysis; San Andreas Fault; seismic data; seismic velocity; seismic wave; wave dispersion; wave propagation https://www.scopus.com/inward/record.uri?eid=2-s2.0-77954633775&doi=10.1111%2fj.1365-246X.2010.04612.x&partnerID=40&md5=e21a49ba6d90b86cb257c805dc5796cc cited By 25 J. Wu J.A. Hole J.A. Snoke article Ferrière2010443 Crater-fill impact breccia and basement rock samples from the 1.07 Ma Bosumtwi impact structure (Ghana) were recovered for the first time in 2004 during an International Continental Scientific Drilling Program (ICDP)-sponsored drilling project. Here, we present detailed results of major-and trace-element analyses of 119 samples from drill core LB-08A, together with the chemical compositions of melt particles from suevite. The meta-graywacke and phyllite/slate crater basement rocks can be easily distinguished from each other on the basis of their bulk chemical compositions. A comparison of the chemical compositions of crater-fill and fallout suevites, as well as between proximal and distal impactites, reveals that LB-08A suevites have higher MgO, CaO, and Na 2 O contents than fallout suevites and, similarly, that the CaO and Na 2 O contents are higher by a factor of approximately two in LB-08A suevites than in Ivory Coast tektites. Noticeable differences occur in Cr, Co, and Ni contents between the different impactites; higher abundances are observed for these elements in distal impactites. The observed differences in composition in the various impactites mainly reflect mixing of different proportions of the original target lithologies, as can be seen in the differences in the clast populations between crater-fill and fallout suevites. However, the original impactite compositions may have also been modifi ed by postimpact alteration, particularly in the proximal impactites. Melt particles in suevite show signifi cant differences in major-element compositions between the different samples investigated, but also within a given sample, indicating that they represent melts derived from different lithologies.© 2010 The Geological Society of America. All rights reserved. Article 2010 English 00721077 10.1130/2010.2465(22) Special Paper of the Geological Society of America 465 Geological Society of America 443 – 469 Ashanti; Ghana; Lake Bosumtwi; Chemical analysis; Core drilling; Fallout; Infill drilling; Magnesia; Rocks; Sodium compounds; Trace elements; Bulk chemical composition; Chemical compositions; Continental scientific drillings; Different proportions; Drilling projects; Impact structures; In compositions; Major and trace elements; basement rock; breccia; chemical composition; crater; geochemistry; impact structure; impactite; suevite; trace element; Meteor impacts https://www.scopus.com/inward/record.uri?eid=2-s2.0-78650961709&doi=10.1130%2f2010.2465%2822%29&partnerID=40&md5=ba1d3315b787f976aff62e4c29283d40 Cited by: 5 Ludovic Ferrière Christian Koeberl Franz Brandstätter Dieter Mader article Flechsig2010443 The Cheb Basin, located in the western Eger (Ohře) Rift, is part of the European Cenozoic Rift system. Although presently non-volcanic, it is the most active area within the European Rift with signs of recent geodynamic activity like emanations of mantle derived CO2, and the repeated occurrence of swarm earthquakes, which are common features in active volcanic regions. It is assumed that the fluids, uprising in permeable channels, play a key role for the genesis of these earthquake swarms. An image of the distribution of the electrical conductivity (resp. resistivity) in the upper crust can give information about the fluid distribution since the electrical patterns reflect pathways of fluids and fluid properties like ionic content. This was the motivation to start both a regional-scale direct current (DC) geoelectrical test covering the Cheb Basin area and several local-scale near surface investigations inside the basin at the seismically active faults Počátky-Plesná Zone (PPZ) and Mariánské Lázně Fault Zone (MLF) near Nový Kostel. It was the research idea to test electrical tomography's ability to detect faults and tectonic deformation in a complex geological environment and to identify characteristic features of these faults. The more methodically justified regional field test mainly aimed at clarifying the opportunity to trace DC electrical signals in an area with known high industrial noise in a sufficient quality. A field set-up with a range of 15-20 km is necessary for an investigation depth of 4-5 km in case of DC geoelectrics. A new developed inversion strategy for sparse electrical data sets allows for a first (coarse) model of resistivity distribution. The near surface investigations in prominent fault zones of the Cheb Basin give more detailed information about the structure of fault zones, divide the sedimentary units in different resistivity zones and detect vertical displacements in the quaternary formations. © 2010 Institute of Geophysics of the ASCR, v.v.i. Article 2010 English 00393169 10.1007/s11200-010-0026-6 Studia Geophysica et Geodaetica 54 443 – 463 3 Bohemia; Cheb Basin; Czech Republic; Karlovarsky; active fault; electrical conductivity; electrical resistivity; fault zone; geodynamics; geoelectric field; mantle source; numerical model; tomography; upper crust; vertical electrical sounding https://www.scopus.com/inward/record.uri?eid=2-s2.0-77957153541&doi=10.1007%2fs11200-010-0026-6&partnerID=40&md5=325d5c3ef717472e0b96d8a0b3d27114 Cited by: 22 Christina Flechsig Tobias Fabig Carsten Rücker Claudia Schütze article Qiu2010150 2010 English 00280836 10.1038/467150a Nature 467 150-151 7312 environmental temperature; geological time; geology; greenhouse; note; paleoclimatology; Paleogene; priority journal; science; sediment; volcano, Dinosauria https://www.scopus.com/inward/record.uri?eid=2-s2.0-77956525245&doi=10.1038%2f467150a&partnerID=40&md5=48d26120bef660f5c2d7793e336587b9 cited By 1 J. Qiu article Jeppson2010 We examine the relationships between borehole geophysical data and physical properties of fault-related rocks within the San Andreas Fault as determined from data from the San Andreas Fault Observatory at Depth borehole. Geophysical logs, cuttings data, and drilling data from the region 3-to 4-km measured depth of the borehole encompass the active part of the San Andreas Fault. The fault zone lies in a sequence of deformed sandstones, siltstone, shale, serpentinite-bearing block-in-matrix rocks, and sheared phyllitic siltstone. The borehole geophysical logs reveal the presence of a low-velocity zone from 3190 to 3410 m measured depth with Vp and Vs values 10-30% lower than the surrounding rocks and a 1-2 m thick zone of active shearing at 3301-3303 m measured depth. Seven low-velocity excursions with increased porosity, decreased density, and mud-gas kick signatures are present in the fault zone. Geologic data on grain-scale deformation and alteration are compared to borehole data and reveal weak correlations and inverse relationships to the geophysical data. In places, Vp and Vs increase with grain-scale deformation and alteration and decrease with porosity in the fault zone. The low-velocity zone is associated with a significant lithologic and structural transition to low-velocity rocks, dominated by phyllosilicates and penetratively foliated, sheared rocks. The zone of active shearing and the regions of low sonic velocity appear to be associated with clay-rich rocks that exhibit fine-scale foliation and higher porosities that may be a consequence of the fault-related shearing of foliated and fine-grained sedimentary rocks. Copyright 2010 by the American Geophysical Union. 2010 English 21699313 10.1029/2010JB007563 Journal of Geophysical Research: Solid Earth 115 Blackwell Publishing Ltd Department of Geology, Utah State University, 4505 Old Main Hill, Logan, UT 84322-4505, United States 12 borehole logging; data inversion; deformation; fault zone; foliation; geophysical method; porosity; rock property; San Andreas Fault; sandstone; shale; siltstone https://www.scopus.com/inward/record.uri?eid=2-s2.0-79251561240&doi=10.1029%2f2010JB007563&partnerID=40&md5=6bcb9dacb91d973b103651e969e6dbc9 cited By 35 T.N. Jeppson K.K. Bradbury J.P. Evans article Virgil201037 Article 2010 English 18163459 10.2204/iodp.sd.9.07.2010 Scientific Drilling 37 – 40 9 https://www.scopus.com/inward/record.uri?eid=2-s2.0-78651584355&doi=10.2204%2fiodp.sd.9.07.2010&partnerID=40&md5=4bd73f17271836f19ce00f01e8be243f Cited by: 8; All Open Access, Gold Open Access, Green Open Access Christopher Virgil Andreas Hördt Torsten Klein Jochem Kück Martin Leven Erich Steveling article Henderson2009134 Lake Qinghai, on the NE Tibetan Plateau, is China's largest natural lake that lies at a triple junction of major climatic influences, making it sensitive to global climate change. As such, the sediments of Lake Qinghai have been the focus of numerous palaeoenvironmental studies spanning a range of timescales. However, as a result of uncertain age controls, uncertainties over interpretation of the proxies, the relative dearth of proxy calibration and lack of understanding of the modern lake system a coherent picture of climate over the NE Tibetan Plateau has yet to emerge from Lake Qinghai's sediment record. We review the state of knowledge for this important site, focusing on the last millennium. A comparison of the major proxy records show significant variability with a general pattern of change over the last 1000 years, notably those linked to the onset of the Little Ice Age, but due to poor chronological constraints a detailed picture of climate change cannot be established. Further, some of the proxy records produced from Lake Qinghai's sediments are open to alternative explanations. This compounds the sediment record as a palaeoenvironmental archive. To fully realise the potential of Lake Qinghai, future research must concentrate on defining a reliable old carbon effect for the lake, calibrating proxy records with climatic processes and understanding spatial variability of proxy records within this large lake. © 2008 Elsevier Ltd and INQUA. Article 2009 English 10406182 10.1016/j.quaint.2008.09.008 Quaternary International 194 134 – 147 1-2 Asia; China; Eurasia; Far East; Qinghai; Qinghai Lake; climate change; Holocene; lacustrine deposit; paleoenvironment; paleolimnology; proxy climate record https://www.scopus.com/inward/record.uri?eid=2-s2.0-58149116517&doi=10.1016%2fj.quaint.2008.09.008&partnerID=40&md5=ca0a28ff8690dbeafb547c2ac6dacd35 Cited by: 95 Andrew C.G. Henderson Jonathan A. Holmes article medvedev2009palaeoproterozoic 2009 Paleontological Journal 43 Springer 972--979 8 PV Medvedev VA Melezhik MM Filippov article Poag2009747 The late Eocene Chesapeake Bay bolide impact transformed its offshore target site from an outer neritic, midshelf seafl oor into a bathyal crater basin. To obtain a depositional record from one of the deepest parts of this basin, the U.S. Geological Survey (USGS) and the International Continental Scientifi c Drilling Program (ICDP) drilled a 1.76-km-deep core hole near Eyreville, Virginia. The Eyreville core and eight previously cored boreholes contain a rarely obtainable record of marine deposition and microfossil assemblages that characterize the transition from synimpact to postimpact paleoenvironments inside and near a submarine impact crater. I used depositional style and benthic foraminiferal assemblages to recognize a four-step transitional succession, with emphasis on the Eyreville core. Step 1 is represented by small-scale, silt-rich turbidites, devoid of indigenous microfossils, which lie directly above the crater-fi lling Exmore breccia. Step 2 is represented by very thin, parallel, silt and clay laminae, which accumulated on a relatively tranquil and stagnant seafl oor. This stagnation created a dead zone, which excluded seafl oor biota, and it lasted ~3-5 ka. Step 3 is an interval of marine clay deposition, accompanied by a burst of microfaunal activity, as a species-rich pioneer community of benthic foraminifera repopulated the impact site. The presence of a diagnostic suite of agglutinated foraminifera during step 3 indicates that paleoenvironmental stress related to the impact lasted from ~9 ka to 400 ka at different locations inside the crater. During step 4, the agglutinated assemblage disappeared, and an equilibrium foraminiferal community developed that contained nearly 100% calcareous species. In contrast to intracrater localities, core sites outside and near the crater rim show neither evidence of the agglutinated assemblage, nor other indications of long-term biotic disruption from the bolide impact. © 2009 The Geological Society of America. 2009 10.1130/2009.2458(32) Special Paper of the Geological Society of America 458 747-773 U.S. Geological Survey, 384 Woods Hole Road, Woods Hole, MA 02543-1598, United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-74949120031&doi=10.1130%2f2009.2458%2832%29&partnerID=40&md5=0791f092ca8f00cfdb1c1b54ddd82c0e cited By 7 C.W. Poag article Poag2009747 The late Eocene Chesapeake Bay bolide impact transformed its offshore target site from an outer neritic, midshelf seafl oor into a bathyal crater basin. To obtain a depositional record from one of the deepest parts of this basin, the U.S. Geological Survey (USGS) and the International Continental Scientifi c Drilling Program (ICDP) drilled a 1.76-km-deep core hole near Eyreville, Virginia. The Eyreville core and eight previously cored boreholes contain a rarely obtainable record of marine deposition and microfossil assemblages that characterize the transition from synimpact to postimpact paleoenvironments inside and near a submarine impact crater. I used depositional style and benthic foraminiferal assemblages to recognize a four-step transitional succession, with emphasis on the Eyreville core. Step 1 is represented by small-scale, silt-rich turbidites, devoid of indigenous microfossils, which lie directly above the crater-fi lling Exmore breccia. Step 2 is represented by very thin, parallel, silt and clay laminae, which accumulated on a relatively tranquil and stagnant seafl oor. This stagnation created a dead zone, which excluded seafl oor biota, and it lasted ~3-5 ka. Step 3 is an interval of marine clay deposition, accompanied by a burst of microfaunal activity, as a species-rich pioneer community of benthic foraminifera repopulated the impact site. The presence of a diagnostic suite of agglutinated foraminifera during step 3 indicates that paleoenvironmental stress related to the impact lasted from ~9 ka to 400 ka at different locations inside the crater. During step 4, the agglutinated assemblage disappeared, and an equilibrium foraminiferal community developed that contained nearly 100% calcareous species. In contrast to intracrater localities, core sites outside and near the crater rim show neither evidence of the agglutinated assemblage, nor other indications of long-term biotic disruption from the bolide impact. © 2009 The Geological Society of America. 2009 English 00721077 10.1130/2009.2458(32) Special Paper of the Geological Society of America 458 Geological Society of America 747-773 U.S. Geological Survey, 384 Woods Hole Road, Woods Hole, MA 02543-1598, United States C (programming language); Deposition; Infill drilling; Offshore oil well production; Silt, Agglutinated foraminifera; Benthic foraminifera; Foraminiferal assemblages; Impact craters; Microfossil assemblages; Offshore targets; Paleoenvironments; U.s. geological surveys, Boreholes, accumulation; benthic foraminifera; bolide; crater; deep drilling; deep-sea sediment; deposition; depositional environment; Eocene; fossil assemblage; geological survey; impact structure; paleoenvironment; turbidite, Chesapeake Bay; United States; Virginia, Foraminifera https://www.scopus.com/inward/record.uri?eid=2-s2.0-74949120031&doi=10.1130%2f2009.2458%2832%29&partnerID=40&md5=0791f092ca8f00cfdb1c1b54ddd82c0e cited By 7 C.W. Poag article Korte2009431 Carbon-isotope stratigraphy is a useful tool for stratigraphic correlation, especially for strata deposited during major perturbations of the carbon cycle that affected the marine, terrestrial and atmospheric reservoirs. For the Triassic-Jurassic boundary, effectively defined by a first-order mass extinction, major fluctuations in carbon-isotope values have been well documented, but these datasets have generally been derived from bulk-rock samples. Hence, the extent to which features of the isotopic curve reflect diagenetic alteration or changing proportions of constituent materials is unconstrained. Here, carbon- and oxygen-isotope data are presented from well-preserved oyster shells (Liostrea) comprising low-magnesium calcite, a mineral species relatively resistant to diagenetic alteration. Samples were obtained from Lavernock Point, Glamorgan, Wales, a coastal section close to a candidate stratotype for the base of the Jurassic at St Audrie's Bay, Somerset, England. The carbon-isotope signature from St Audrie's Bay, previously defined on the basis of analysis of bulk organic matter, is confirmed by our new data. Major features are (1) the upper part of an 'initial' negative isotope excursion in the lowest part of the section, followed by (2) a pronounced positive excursion, and (3) an extended 'main' negative isotope excursion in the highest part of the section. The data confirm that the carbon-isotope stratigraphy previously documented from bulk organic matter in SW England records the chemical composition of the contemporaneous seawater. Bulk carbonates sampled over the same interval near Lyme Regis, England, show similar trends to those from oyster calcite in the lower part of the study section, but there are more 13C-depleted values up-section. These lower values probably result from an admixture of primary and diagenetic carbonate. Palaeotemperatures calculated from oxygen-isotope values from Lavernock Point oyster shells are relatively cool at the beginning of the positive carbon-isotope excursion, and increased by up to 10 8C during the main negative carbon-isotope excursion. The new results are compatible with the view that positive carbon-isotope excursions correspond to times of low atmospheric carbon dioxide content, whereas negative carbon-isotope excursions correspond to times of high atmospheric carbon dioxide content, as is also found to be the case during the Early Jurassic (Toarcian) Oceanic Anoxic Event. The Mg/Ca and Sr/Ca ratios and 18O of investigated Liostrea hisingeri show no correlation,supporting data from modern bivalves that indicate that incorporation of Mg and Sr is controlled mainly by factors other than temperature. © 2009 Geological Society of London. Article 2009 English 00167649 10.1144/0016-76492007-177 Journal of the Geological Society 166 431 – 445 3 England; Eurasia; Europe; Glamorgan; Saint Audrie's Bay; Somerset; United Kingdom; Wales; Western Europe; Bivalvia; Ostreidae; carbon cycle; carbon dioxide; carbon isotope; chemical composition; Jurassic; oxygen isotope; paleoenvironment; paleotemperature; seawater; stratigraphic boundary; stratigraphic correlation; Triassic https://www.scopus.com/inward/record.uri?eid=2-s2.0-64749095283&doi=10.1144%2f0016-76492007-177&partnerID=40&md5=3b1a1884a96f5f2b0ebf0b9f3a6c6ef9 Cited by: 124 Christoph Korte Stephen P. Hesselbo Hugh C. Jenkyns Rosalind E.M. Rickaby Christoph Spötl article Self-Trail2009633 Biostratigraphic analysis of sedimentary breccias and diamictons in the Chesapeake Bay impact structure provides information regarding the timing and processes of late-stage gravitational crater collapse and ocean resurge. Studies of calcareous nannofossil and palynomorph assemblages in the International Continental Scientific Drilling Program (ICDP)-U.S. Geological Survey (USGS) Eyreville A and B cores show the mixed-age, mixed-preservation microfossil assemblages that are typical of deposits from the upper part of the Chesapeake Bay impact structure. Sparse, poorly preserved, possibly thermally altered pollen is present within a gravelly sand interval below the granite slab at 1392 m in Eyreville core B, an interval that is otherwise barren of calcareous nannofossils and dinocysts. Gravitational collapse of watersaturated sediments from the transient crater wall resulted in the deposition of sediment clasts primarily derived from the nonmarine Cretaceous Potomac Formation. Collapse occurred before the arrival of resurge. Low pollen Thermal Alteration Index (TAI) values suggest that these sediments were not thermally altered by contact with the melt sheet. The arrival of resurge sedimentation is identified based on the presence of diamicton zones and stringers rich in glauconite and marine microfossils at 866.7 m. This horizon can be traced across the crater and can be used to identify gravitational collapse versus ocean-resurge sedimentation. Glauconitic quartz sand diamicton dominates the sediments above 618.2 m. Calcareous nannofossil and dinoflagellate data from this interval suggest that the earliest arriving resurge from the west contained little or no Cretaceous marine input, but later resurge pulses mined Cretaceous sediments east of the Watkins core in the annular trough. Additionally, the increased distance traveled by resurge to the central crater in turbulent flow conditions resulted in the disaggregation of Paleogene unconsolidated sediments. As a result, intact Paleogene clasts in Eyreville cores are rare, but clasts of semilithified Potomac Formation silts and clays are common. © 2009 The Geological Society of America. 2009 English 00721077 10.1130/2009.2458(28) Special Paper of the Geological Society of America 458 Geological Society of America 633-654 U.S. Geological Survey, 926A National Center, Reston, VA 20192, United States Gravitational effects; Infill drilling; Mica; Stars, Biostratigraphic analysis; Calcareous nannofossil; Calcareous nannofossils; Chesapeake bay impact structures; Continental scientific drillings; Microfossil assemblages; U.s. geological surveys; Unconsolidated sediment, Sediments, biostratigraphy; breccia; crater; diamicton; dinoflagellate cyst; fossil assemblage; infill; microfossil; micropaleontology; Paleogene; palynomorph; pollen; research program; sedimentation; turbulent flow, Chesapeake Bay; United States, Dinophyceae https://www.scopus.com/inward/record.uri?eid=2-s2.0-74949125569&doi=10.1130%2f2009.2458%2828%29&partnerID=40&md5=580f6f3fa77269508c9ff0896daf5bbf cited By 17 J.M. Self-Trail L.E. Edwards R.J. Litwin article Townsend2009255 The Eyreville B core from the Chesapeake Bay impact structure, Virginia, USA, contains a lower basement-derived section (1551.19 m to 1766.32 m deep) and two megablocks of dominantly (1) amphibolite (1376.38 m to 1389.35 m deep) and (2) granite (1095.74 m to 1371.11 m deep), which are separated by an impactite succession. Metasedimentary rocks (muscovite-quartz-plagioclase-biotite-graphite ± fibrolite ± garnet ± tourmaline ± pyrite ± rutile ± pyrrhotite mica schist, hornblende-plagioclase-epidote-biotite- K-feldspar-quartz-titanite-calcite amphibolite, and vesuvianite-plagioclase- quartz-epidote calc-silicate rock) are dominant in the upper part of the lower basement-derived section, and they are intruded by pegmatitic to coarse-grained granite (K-feldspar-plagioclase-quartz-muscovite ± biotite ± garnet) that increases in volume proportion downward. The granite megablock contains both gneissic and weakly or nonfoliated biotite granite varieties (K-feldspar-quartz-plagioclase-biotite ± muscovite ± pyrite), with small schist xenoliths consisting of biotite-plagioclase-quartz ± epidote ± amphibole. The lower basement-derived section and both megablocks exhibit similar middleto upper-amphibolite-facies metamorphic grades that suggest they might represent parts of a single terrane. However, the mica schists in the lower basement-derived sequence and in the megablock xenoliths show differences in both mineralogy and whole-rock chemistry that suggest a more mafi c source for the xenoliths. Similarly, the mineralogy of the amphibolite in the lower basement-derived section and its association with calc-silicate rock suggest a sedimentary protolith, whereas the bulk-rock and mineral chemistry of the megablock amphibolite indicate an igneous protolith. The lower basement-derived granite also shows bulk chemical and mineralogical differences from the megablock gneissic and biotite granites. © 2009 The Geological Society of America. 2009 English 00721077 10.1130/2009.2458(13) Special Paper of the Geological Society of America 458 Geological Society of America 255-275 Impact Cratering Research Group, School of Geosciences, University of the Witwatersrand, P.O. WITS, Johannesburg 2050, South Africa; U.S. Geological Survey, 926A National Center, Reston, VA 20192, United States; Museum für Naturkunde-Leibniz Institute, Humboldt University Berlin, Invalidenstrasse 43, 10115 Berlin, Germany; Department of Geological Sciences, University of Vienna, Althanstrasse 14, Vienna A-1090, Austria Biotite; Buildings; Calcite; Feldspar; Granite; Quartz; Sedimentary rocks; Silicate minerals, Amphibolite facies; Biotite granite; Chesapeake bay impact structures; Crystalline basement; Metamorphic grade; Metasedimentary rocks; Mineral chemistry; Silicate rocks, Mica, amphibolite; crater; geochemistry; granite; impact structure; impactite; metasedimentary rock; petrography; schist, Chesapeake Bay; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-74949135099&doi=10.1130%2f2009.2458%2813%29&partnerID=40&md5=1c0a2e477486c4610058a2cc1a6ec85c cited By 18 G.N. Townsend R.L. Gibson J.W. Horton Jr. W.U. Reimold R.T. Schmitt K. Bartosova article Wittmann2009377 The Eyreville B drill core in the inner annular moat of the 85-km-diameter Chesapeake Bay impact structure recovered the first coherent impact melt volumes from within the crater as two bodies, 1 and 5.5 m thick. This study focuses on the petrogenesis of these well-preserved rocks. Mixing calculations reveal that the chemical composition of these melts can be modeled as a hybrid of ̃40% sedimentary target and ̃60% crystalline basement component. The melt rocks contain abundant lithic and mineral clasts that display all stages of shock metamorphism. Zircon clasts record the cooling of the melt from temperatures above 1700 °C to below 1200 °C within the first minutes after formation. Glassy melt with a peraluminous, rhyolitic composition that contains ̃5 wt% water is preserved. This melt records a crystallization sequence of aluminum-rich orthopyroxene and hercynitic spinel, followed by plagioclase, titanomagnetite and cordierite, and late sanidine. Spherulitic aluminosilicate-SiO 2 -cordierite aggregates that are comparable to buchites at temperatures below ̃1465 °C complement this assemblage. Lack of hyaloclastic fragmentation suggests dry emplacement conditions. Complete cooling by conductive heat transfer took ̃7 weeks and ̃4 years for the 1-m- and the 5.5-m-thick melt bodies, respectively. Alteration stages below ̃100 °C produced smectite, phillipsite, chalcedony, and a rare zeolite phase that is tentatively identified as terranovaite. © 2009 The Geological Society of America. 2009 English 00721077 10.1130/2009.2458(17) Special Paper of the Geological Society of America 458 Geological Society of America 377-396 Lunar and Planetary Institute, 3600 Bay Area Boulevard, Houston, TX 77058, United States; Museum für Naturkunde-Leibniz Institute, Humboldt University Berlin, Invalidenstrasse 43, 10115 Berlin, Germany; Florida Institute of Technology, Melbourne, FL 32901, United States Feldspar; Heat transfer; Infill drilling; Petrology; Silica; Silicate minerals; Structural geology; Zeolites; Zircon, Chemical compositions; Chesapeake Bay; Chesapeake bay impact structures; Conductive heat transfer; Crystalline basement; Emplacement conditions; Mixing calculations; Titanomagnetites, Core drilling, crater; crystallization; impact structure; marine sediment; petrogenesis; shock metamorphism, Chesapeake Bay; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-74949125572&doi=10.1130%2f2009.2458%2817%29&partnerID=40&md5=e7616e231af48a47e2a9002b0853c5b7 cited By 40 A. Wittmann R.T. Schmitt L. Hecht D.A. Kring W.U. Reimold H. Povenmire article Townsend2009255 The Eyreville B core from the Chesapeake Bay impact structure, Virginia, USA, contains a lower basement-derived section (1551.19 m to 1766.32 m deep) and two megablocks of dominantly (1) amphibolite (1376.38 m to 1389.35 m deep) and (2) granite (1095.74 m to 1371.11 m deep), which are separated by an impactite succession. Metasedimentary rocks (muscovite-quartz-plagioclase-biotite-graphite ± fibrolite ± garnet ± tourmaline ± pyrite ± rutile ± pyrrhotite mica schist, hornblende-plagioclase-epidote-biotite- K-feldspar-quartz-titanite-calcite amphibolite, and vesuvianite-plagioclase- quartz-epidote calc-silicate rock) are dominant in the upper part of the lower basement-derived section, and they are intruded by pegmatitic to coarse-grained granite (K-feldspar-plagioclase-quartz-muscovite ± biotite ± garnet) that increases in volume proportion downward. The granite megablock contains both gneissic and weakly or nonfoliated biotite granite varieties (K-feldspar-quartz-plagioclase-biotite ± muscovite ± pyrite), with small schist xenoliths consisting of biotite-plagioclase-quartz ± epidote ± amphibole. The lower basement-derived section and both megablocks exhibit similar middleto upper-amphibolite-facies metamorphic grades that suggest they might represent parts of a single terrane. However, the mica schists in the lower basement-derived sequence and in the megablock xenoliths show differences in both mineralogy and whole-rock chemistry that suggest a more mafi c source for the xenoliths. Similarly, the mineralogy of the amphibolite in the lower basement-derived section and its association with calc-silicate rock suggest a sedimentary protolith, whereas the bulk-rock and mineral chemistry of the megablock amphibolite indicate an igneous protolith. The lower basement-derived granite also shows bulk chemical and mineralogical differences from the megablock gneissic and biotite granites. © 2009 The Geological Society of America. 2009 10.1130/2009.2458(13) Special Paper of the Geological Society of America 458 255-275 Impact Cratering Research Group, School of Geosciences, University of the Witwatersrand, P.O. WITS, Johannesburg 2050, South Africa; U.S. Geological Survey, 926A National Center, Reston, VA 20192, United States; Museum für Naturkunde-Leibniz Institute, Humboldt University Berlin, Invalidenstrasse 43, 10115 Berlin, Germany; Department of Geological Sciences, University of Vienna, Althanstrasse 14, Vienna A-1090, Austria https://www.scopus.com/inward/record.uri?eid=2-s2.0-74949135099&doi=10.1130%2f2009.2458%2813%29&partnerID=40&md5=1c0a2e477486c4610058a2cc1a6ec85c cited By 18 G.N. Townsend R.L. Gibson J.W. Horton Jr. W.U. Reimold R.T. Schmitt K. Bartosova article Bartosova2009317 The moat of the 85-km-diameter and 35.3-Ma-old Chesapeake Bay impact structure (USA) was drilled at Eyreville Farm in 2005-2006 as part of an International Continental Scientific Drilling Program (ICDP)-U.S. Geological Survey (USGS) drilling project. The Eyreville drilling penetrated postimpact sediments and impactites, as well as crystalline basement-derived material, to a total depth of 1766 m. We present petrographic observations on 43 samples of suevite, impact melt rock, polymict lithic impact breccia, cataclastic gneiss, and clasts in suevite, from the impact breccia section from 1397 to 1551 m depth in the Eyreville B drill core. Suevite samples have a fine-grained clastic matrix and contain a variety of mineral and rock clasts, including sedimentary, metamorphic, and igneous lithologies. Six subunits (U1-U6, from top to bottom) are distinguished in the impact breccia section based on abundance of different clasts, melt particles, and matrix; the boundaries between the subunits are generally gradational. Sedimentary clasts are dominant in most subunits (especially in U1, but also in U3, U4, and U6). There are two melt-rich subunits (U1 and U3), and there are two melt-poor subunits with predominantly crystalline clasts (U2 and U5). The lower part (subunits U5 and U6), which has large blocks of cataclastic gneiss and rare melt particles, probably represents ground-surge material. Subunit U1 possibly represents fallback material, since it contains shard-like melt particles that were solidified before incorporation into the breccia. The melt-poor, crystalline clast-rich subunit U2 could have been formed by slumping of material, probably from the central uplift or from the margin of the transient crater. Melt particles are most abundant near the top of the impact breccia section (above 1409 m) and around 1450 m, where the suevite grades into impact melt rock. Five different types of melt particles have been recognized: (1) clear colorless to brownish glass; (2) melt altered to fine-grained phyllosilicate minerals; (3) recrystallized silica melt; (4) melt with microlites; and (5) dark-brown melt. Proportions of matrix and melt in the suevite are highly variable (̃2-67 vol% and 1-67 vol%, respectively; the remainder consists of lithic clasts). Quartz grains in suevite commonly show planar fractures (PFs) and/or planar deformation features (PDFs; 1 or 2 sets, rarely more); some PDFs are decorated. On average, ̃16 rel% of quartz grains in suevite samples are shocked (i.e., show PFs and/or PDFs). Sedimentary clasts (e.g., graywacke or sandstone) and polycrystalline quartz clasts have relatively higher proportions of shocked quartz grains, whereas quartz grains in schist and gneiss clasts rarely show shock effects. Rare feldspar grains with PDFs and mica with kink banding were observed. Ballen quartz was noted in melt-rich samples. Evidence of hydrothermal alteration, namely, the presence of smectite and secondary carbonate veins, was found especially in the lower parts of the impact breccia section. © 2009 The Geological Society of America. 2009 English 00721077 10.1130/2009.2458(15) Special Paper of the Geological Society of America 458 Geological Society of America 317-348 Department of Lithospheric Research, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria; Department of Earth Sciences, University of Western Ontario, 1151 Richmond Street, London, ON, N6A 5B7, Canada; Museum für Naturkunde-Leibniz Institute, Humboldt University Berlin, Invalidenstrasse 43, 10115 Berlin, Germany; Department of Geodynamics and Sedimentology, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria Binary alloys; Clay alteration; Crystalline materials; Crystalline rocks; Drills; Feldspar; Igneous rocks; Infill drilling; Metamorphic rocks; Mica; Quartz; Sedimentary rocks; Sedimentology; Silicate minerals; Silicon alloys, Chesapeake bay impact structures; Continental scientific drillings; Crystalline basement; Derived materials; Hydrothermal alterations; Planar deformation; Polycrystalline quartz; U.s. geological surveys, Core drilling, breccia; crater; drilling; hydrothermal alteration; impact structure; impactite; petrography; shock metamorphism; suevite, Chesapeake Bay; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-74949111899&doi=10.1130%2f2009.2458%2815%29&partnerID=40&md5=f6213b90d8ec6edd96de8e5c99e99753 cited By 14 K. Bartosova L. Ferrière C. Koeberl W.U. Reimold S. Gier article Reimold2009655 The International Continental Scientific Drilling Program (ICDP)-U.S. Geological Survey (USGS) Eyreville A and B drill cores sampled crater fill in the region of the crater moat, ̃9 km to the NE of the center of the Chesapeake Bay impact structure, Virginia, USA. They provide a 953 m section (444-1397 m depth) of sedimentary clast breccia and intercalated sedimentary and crystalline megablocks knownas Exmore beds, deposited on top of the impactite sequence between 1397 and 1551 m depth. We petrographically investigated the sandy-clayey groundmass-dominated breccia, which resembles a diamictite ("Exmore breccia"), and which, in its lower parts, carries sedimentary and crystalline blocks. The entire breccia interval is characterizedby the presence of glauconite and bioclastic carbonate, which distinguishes the Exmore breccia from other sandy facies above and below in the stratigraphy. The sediment-clast breccia exhibits strong heterogeneity from sample to sample with respect to groundmass nature, e.g., clay versus sand content, as well as clast content, in general, and shocked clast content, in particular. There is a consistently signifi cantly larger macroscopic sedimentary to crystalline clast content. On the microscopic scale, the intersample sediment to crystalline clast ratios are quite variable. A very small component of shocked material, in the form of shock-deformed quartz, and to an even lesser degree feldspar, and somewhat more abundant but still relatively scarce shardshaped,altered melt particles, is present throughout the section. However, between ̃458 and 469 m, and between 514 and 527 m depths, the abundance of such melt particlesis notably enhanced. These sections are also chemically distinct and relatively more mafic than the other parts of the Exmore breccia. It appears that from the time of deposition of the 527 m material, calming of the ocean occurred over the crater area as a result of abatement of resurge activity, so that ejecta from the plume abovethe crater could accumulate within the crater area to a larger degree. Deposition ofejecta fallout from the collapsing ejecta plume was terminated by the time of deposition of the 458 m material. This raises questions about the positioning of the exact upper contact of Exmore breccia to post-Exmore sediment (Chickahominy Formation), which is currently placed at 444 m depth and which possibly should be revisedto 458 m depth. Based on a signifi cant record of granite-derived material with shocked minerals, the shocked debris component seems to be largely derived from crystalline target rocks. This provides further evidence that the basement-derived material of the basal section of the Eyreville drill cores, which is essentially unshocked, is likely of an allochthonous nature and that the drilling did not intersect the actual crater floor. 76°W. © 2009 Geological Society of America. 2009 English 00721077 10.1130/2009.2458(29) Special Paper of the Geological Society of America 458 Geological Society of America 655-698 Museum f̈r Naturkunde-Leibniz Institute, Humboldt University Berlin, Invalidenstrasse 43, D-10115 Berlin, Germany; Department of Lithospheric Research, University of Vienna, Althanstrasse 14, A-1090 VA, Austria; Lunar and Planetary Institute, 3600 Bay Area Boulevard, Houston, TX 77058, United States; U.S. Geological Survey, MS 926A, 12201 Sunrise Valley Drive, Reston, VA 20192, United States Crystalline materials; Crystalline rocks; Deposition; Drills; Feldspar; Infill drilling; Mica; Rocks; Sedimentology; Sediments; Stratigraphy, Bioclastic carbonates; Chesapeake bay impact structures; Continental scientific drillings; Crystalline target rocks; Derived materials; Microscopic scale; Strong heterogeneities; U.s. geological surveys, Core drilling, bedform; breccia; clast; crater; deposition; heterogeneity; impactite; particle size; petrography; research program; sedimentary petrology; shock metamorphism, Chesapeake Bay; United States; Virginia https://www.scopus.com/inward/record.uri?eid=2-s2.0-74949125250&doi=10.1130%2f2009.2458%2829%29&partnerID=40&md5=964dbbd7a3d357b21a6f3aecd4a7c5bf cited By 27 W.U. Reimold K. Bartosova R.T. Schmitt B. Hansen C. Crasselt C. Koeberl A. Wittmann D.S. Powars article melezhik2009petroleum 2009 Terra Nova 21 Wiley Online Library 119--126 2 Victor A Melezhik Anthony E Fallick Michail M Filippov Aivo Lepland Dmitry V Rychanchik Yuliya E Deines Pavel V Medvedev Alexander E Romashkin Harald Strauss article Wittmann2009377 The Eyreville B drill core in the inner annular moat of the 85-km-diameter Chesapeake Bay impact structure recovered the first coherent impact melt volumes from within the crater as two bodies, 1 and 5.5 m thick. This study focuses on the petrogenesis of these well-preserved rocks. Mixing calculations reveal that the chemical composition of these melts can be modeled as a hybrid of ̃40% sedimentary target and ̃60% crystalline basement component. The melt rocks contain abundant lithic and mineral clasts that display all stages of shock metamorphism. Zircon clasts record the cooling of the melt from temperatures above 1700 °C to below 1200 °C within the first minutes after formation. Glassy melt with a peraluminous, rhyolitic composition that contains ̃5 wt% water is preserved. This melt records a crystallization sequence of aluminum-rich orthopyroxene and hercynitic spinel, followed by plagioclase, titanomagnetite and cordierite, and late sanidine. Spherulitic aluminosilicate-SiO 2 -cordierite aggregates that are comparable to buchites at temperatures below ̃1465 °C complement this assemblage. Lack of hyaloclastic fragmentation suggests dry emplacement conditions. Complete cooling by conductive heat transfer took ̃7 weeks and ̃4 years for the 1-m- and the 5.5-m-thick melt bodies, respectively. Alteration stages below ̃100 °C produced smectite, phillipsite, chalcedony, and a rare zeolite phase that is tentatively identified as terranovaite. © 2009 The Geological Society of America. 2009 10.1130/2009.2458(17) Special Paper of the Geological Society of America 458 377-396 Lunar and Planetary Institute, 3600 Bay Area Boulevard, Houston, TX 77058, United States; Museum für Naturkunde-Leibniz Institute, Humboldt University Berlin, Invalidenstrasse 43, 10115 Berlin, Germany; Florida Institute of Technology, Melbourne, FL 32901, United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-74949125572&doi=10.1130%2f2009.2458%2817%29&partnerID=40&md5=e7616e231af48a47e2a9002b0853c5b7 cited By 40 A. Wittmann R.T. Schmitt L. Hecht D.A. Kring W.U. Reimold H. Povenmire article Pierce2009165 The International Continental Scientific Drilling Program (ICDP) and the U.S. Geological Survey (USGS) drilled three core holes to a composite depth of 1766 m within the moat of the Chesapeake Bay impact structure. Core recovery rates from the drilling were high (̃90%), but problems with core hole collapse limited the geophysical downhole logging to natural-gamma and temperature logs. To supplement the downhole logs, ̃5% of the Chesapeake Bay impact structure cores was processed through the USGS GeoTek multisensor core logger (MSCL) located in Menlo Park, California. The measured physical properties included core thickness (cm), density (g cm -3 ), P-wave velocity (m s -1 ), P-wave amplitude (%), magnetic susceptibility (cgs), and resistivity (ohm-m). Fractional porosity was a secondary calculated property. The MSCL data-sampling interval for all core sections was 1 cm longitudinally. Photos of each MSCL sampled core section were imbedded with the physical property data for direct comparison. These data have been used in seismic, geologic, thermal history, magnetic, and gravity models of the Chesapeake Bay impact structure. Each physical property curve has a unique signature when viewed over the full depth of the Chesapeake Bay impact structure core holes. Variations in the measured properties reflect differences in pre-impact target-rock lithologies and spatial variations in impact-related deformation during late-stage crater collapse and ocean resurge. © 2009 The Geological Society of America. 2009 English 00721077 10.1130/2009.2458(08) Special Paper of the Geological Society of America 458 Geological Society of America 165-179 U.S. Geological Survey, 926A National Center, Reston, VA 20192, United States Boreholes; Infill drilling; Magnetic susceptibility; Seismic waves; Thermal logging; Wave propagation, Chesapeake bay impact structures; Continental scientific drillings; Measured properties; P-wave velocity; Spatial variations; Temperature log; Thermal history; U.s. geological surveys, Structural properties, crater; deformation; drilling; geophysical method; impact structure; magnetic susceptibility; P-wave; physical property, Chesapeake Bay; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-74949088487&doi=10.1130%2f2009.2458%2808%29&partnerID=40&md5=7eb8a5759465febc0a0ce5f7de8d6914 cited By 7 H.A. Pierce J.B. Murray article Mayr2009137 The physical properties of rocks in drill core from impact structures can be used to distinguish individual nonimpact and impact-generated lithologies, and to investigate the effect of the impact process on the target rocks. Here, we present the results of laboratory measurements of porosity, density, velocity, and thermal properties on the densely sampled cores from the Eyreville borehole in the Chesapeake Bay impact structure, USA. With increasing depth, the lithologies encountered (and porosities) are: postimpact sediments (40%-60%), Exmore breccia and sedimentary blocks (27%-44%), a large megablock of granitoids (<1%), suevite and polymict lithic impact breccia (1%-25%), and schist, granite, and pegmatite of the basementderived section (1%-13%). The low bulk densities and thermal properties of the postimpact sediments show a good correlation with the high porosity values. The physical properties within the Exmore bed sequence overall display relatively small variation but are heterogeneous on the core sample scale. Physical properties along the impact-breccia sequence are highly variable on all scales, and they are interpreted to be controlled by the structural arrangement of particles as well as by the highly variable mineral and clast compositions of the samples. The physical properties of the rocks of the lowermost basement-derived section are also heterogeneous and are interpreted as having been influenced by both lithology and overprinting as a result of the impact process. These results are important for further lithological and petrophysical interpretation and for calibrating future geophysical models of the Chesapeake Bay impact structure. © 2009 The Geological Society of America. 2009 English 00721077 10.1130/2009.2458(07) Special Paper of the Geological Society of America 458 Geological Society of America 137-163 Fachgebiet Angewandte Geophysik, Technische Universität Berlin, Sekr. ACK 2, Ackerstrasse 71-76, D-13355 Berlin, Germany; Russian State Geological Prospecting University, 23 Miklukho-Maklai Street, Moscow, 117997, Russian Federation; Geophysical Institute, Universität Karlsruhe, Hertzstrasse 16, 76187 Karlsruhe, Germany Boreholes; Core drilling; Granite; Infill drilling; Lithology; Porosity; Structural geology; Thermodynamic properties, Chesapeake bay impact structures; Geophysical models; Good correlations; Impact structures; Laboratory measurements; Petrophysical interpretation; Small variations; Structural arrangement, Structural properties, breccia; bulk density; impact structure; physical property; porosity; rock property; sedimentary structure, Chesapeake Bay; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-74949128569&doi=10.1130%2f2009.2458%2807%29&partnerID=40&md5=be039756fc59ae4363635ea566115c4d cited By 8 S.I. Mayr H. Burkhardt Y. Popov R. Romushkevich D. Miklashevskiy D. Gorobtsov P. Heidinger H. Wilhelm article hui2009organic 2009 Earth Science Frontiers 16 96 6 KONG Hui HUANG Yong-Jian HUANG Qing-Hua ZHANG Wen-Jing XIE Lei LIU Hua-Gong XIE Xiao-Yun article Mayr2009137 The physical properties of rocks in drill core from impact structures can be used to distinguish individual nonimpact and impact-generated lithologies, and to investigate the effect of the impact process on the target rocks. Here, we present the results of laboratory measurements of porosity, density, velocity, and thermal properties on the densely sampled cores from the Eyreville borehole in the Chesapeake Bay impact structure, USA. With increasing depth, the lithologies encountered (and porosities) are: postimpact sediments (40%-60%), Exmore breccia and sedimentary blocks (27%-44%), a large megablock of granitoids (<1%), suevite and polymict lithic impact breccia (1%-25%), and schist, granite, and pegmatite of the basementderived section (1%-13%). The low bulk densities and thermal properties of the postimpact sediments show a good correlation with the high porosity values. The physical properties within the Exmore bed sequence overall display relatively small variation but are heterogeneous on the core sample scale. Physical properties along the impact-breccia sequence are highly variable on all scales, and they are interpreted to be controlled by the structural arrangement of particles as well as by the highly variable mineral and clast compositions of the samples. The physical properties of the rocks of the lowermost basement-derived section are also heterogeneous and are interpreted as having been influenced by both lithology and overprinting as a result of the impact process. These results are important for further lithological and petrophysical interpretation and for calibrating future geophysical models of the Chesapeake Bay impact structure. © 2009 The Geological Society of America. 2009 10.1130/2009.2458(07) Special Paper of the Geological Society of America 458 137-163 Fachgebiet Angewandte Geophysik, Technische Universität Berlin, Sekr. ACK 2, Ackerstrasse 71-76, D-13355 Berlin, Germany; Russian State Geological Prospecting University, 23 Miklukho-Maklai Street, Moscow, 117997, Russian Federation; Geophysical Institute, Universität Karlsruhe, Hertzstrasse 16, 76187 Karlsruhe, Germany https://www.scopus.com/inward/record.uri?eid=2-s2.0-74949128569&doi=10.1130%2f2009.2458%2807%29&partnerID=40&md5=be039756fc59ae4363635ea566115c4d cited By 8 S.I. Mayr H. Burkhardt Y. Popov R. Romushkevich D. Miklashevskiy D. Gorobtsov P. Heidinger H. Wilhelm conference Dallimore2009 Canada has been involved in assessing the energy potential of gas hydrates since the 1970's when the Geological Survey of Canada (GSC) assisted industry in appraising problems encountered during exploratory drilling in the Arctic. This work led to the first regional studies of permafrost gas hydrates in the 1980s and preliminary resource estimates in the 1990s. On Canada's Pacific coast GSC researchers first discovered the widespread characteristic gas hydrate bottom-simulating reflector in multichannel seismic surveys in 1985. Since then there has been extensive multi-disciplinary surveys/studies by GSC, Canadian universities, and international scientists on Canada's west and east coasts. Two ODP/IOPD expeditions have been dedicated to sampling and measuring gas hydrates off Vancouver Island. Over the past decade Canada has played a leading role internationally in hydrate production technology, improving geophysical detection techniques, and undertaking laboratory investigations of geologic controls. In 1998, the GSC, in partnership with the Japan National Oil Corporation, recovered the world's first Arctic gas hydrate-bearing core samples from the Mallik site, Mackenzie Delta. This program defined a highly concentrated, reservoir-scale occurrence of gas hydrates within a potentially producible porous sand matrix. In 2002, a five-nation international research consortium (Canada, Japan, USA, Germany, India) conducted large- and small-scale production experiments at Mallik to evaluate the efficiency of pressure reduction vs. heat stimulation for initiating in situ dissociation of gas. These experiments, along with state-of-the-art well logging and extensive post-field laboratory studies, provided critical scientific and technical data supporting the design and engineering of a subsequent Canada-Japan extended production testing program conducted during the winters of 2007/2008. In March 2008, 6 days of continuous methane production were achieved by depressurization of a concentrated gas hydrate interval. The Mallik test results have been widely acknowledged as "Proof of Concept" for the production of methane from hydrates by the depressurization method. 2009 English 9780841224414 00657727 ACS National Meeting Book of Abstracts Geological Survey of Canada, P.O. Box 5000, Sidney, BC V8L 5S1, Canada https://www.scopus.com/inward/record.uri?eid=2-s2.0-78649527911&partnerID=40&md5=d55e64d59997814cb6754454c0515174 cited By 0 S.R. Dallimore article brigham2009lake 2009 PAGES (Past Global Changes) News 17 PAGES International Project Office 19-21 1 J Brigham-Grette M Melles P Minyuk C Koeberl others article Schleicher2009173 A detailed mineralogical study is presented of the matrix of mudrocks sampled from spot coring at three key locations along the San Andreas Fault Observatory at depth (SAFOD) drill hole. The characteristics of authigenic illite-smectite (I-S) and chlorite-smectite (C-S) mixed-layer mineral clays indicate a deep diagenetic origin. A randomly ordered I-S mineral with ca. 20-25% smectite layers is one of the dominant authigenic clay species across the San Andreas Fault zone (sampled at 3,066 and 3,436 m measured depths/MD), whereas an authigenic illite with ca. 2-5% smectite layers is the dominant phase beneath the fault (sampled at 3,992 m MD). The most smectite-rich mixed-layered assemblage with the highest water content occurs in the actively deforming creep zone at ca. 3,300-3,353 m (true vertical depth of ca. 2.7 km), with I-S (70:30) and C-S (50:50). The matrix of all mudrock samples show extensive quartz and feldspar (both plagioclase and K-feldspar) dissolution associated with the crystallization of pore-filling clay minerals. However, the effect of rock deformation in the matrix appears only minor, with weak flattening fabrics defined largely by kinked and fractured mica grains. Adopting available kinetic models for the crystallization of I-S in burial sedimentary environments and the current borehole depths and thermal structure, the conditions and timing of I-S growth can be evaluated. Assuming a typical K+ concentration of 100-200 ppm for sedimentary brines, a present-day geothermal gradient of 35°C/km and a borehole temperature of ca. 112°C for the sampled depths, most of the I-S minerals can be predicted to have formed over the last 4-11 Ma and are probably still in equilibrium with circulating fluids. The exception to this simple burial pattern is the occurrence of the mixed layered phases with higher smectite content than predicted by the burial model. These minerals, which characterize the actively creeping section of the fault and local thin film clay coating on polished brittle slip surfaces, can be explained by the influence of either cooler fluids circulating along this segment of the fault or the flow of K+-depleted brines. © Springer-Verlag 2008. 2009 English 00107999 10.1007/s00410-008-0328-7 Contributions to Mineralogy and Petrology 157 173-187 Geozentrum Nordbayern, Universität Erlangen-Nürnberg, Schloßgarten 5, 91054 Erlangen, Germany; Institut für Geographie und Geologie, Ernst-Moritz-Arndt-Universität Greifswald, Friedrich-Ludwig-Jahn-Str. 17a, 17487 Greifswald, Germany; Department of Geological Sciences, University of Michigan, 1100 N. University Ave., Ann Arbor, MI 48109, United States 2 chlorite; crystallization; deformation mechanism; diagenesis; illite; mudstone; San Andreas Fault; smectite; thermal structure, California; North America; Parkfield; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-57849148044&doi=10.1007%2fs00410-008-0328-7&partnerID=40&md5=4605ba50225212c3a552420b6cd39a9a cited By 52 A.M. Schleicher L.N. Warr B.A. Pluijm article Christeson2009249 The surface expression of impact craters is well-known from visual images of the Moon, Venus, and other planets and planetary bodies, but constraints on deep structure of these craters is largely limited to interpretations of gravity data. Although the gravity models are non-unique, they do suggest that large impact craters are associated with structure at the base of the crust. We use seismic data to map Moho (crust-mantle interface) topography beneath the Chicxulub crater, the youngest and best preserved of the three largest known terrestrial impact craters. The Moho is upwarped by ~ 1.5-2 km near the center of the Chicxulub crater, and depressed by ~ 0.5-1.0 km at a distance of ~ 30-55 km from the crater center. A comparison with numerical modeling results reveal that immediately following impact a transient crater reached a maximum depth of at least 30 km prior to collapse, and that subsequent collapse of the transient crater uplifted target material from deep below the crater floor. These results demonstrate that deformation from large terrestrial impacts can extend to the base of the continental crust. A similar Moho topography is also modeled for some large lunar and Martian craters, which suggests that mantle deformation may play a prominent role in large crater formation. © 2009 Elsevier B.V. All rights reserved. 2009 10.1016/j.epsl.2009.04.033 Earth and Planetary Science Letters 284 249-257 University of Texas, Institute for Geophysics, Jackson School of Geosciences, 10100 Burnet Rd, Austin, TX 78758, United States; Department of Earth Science and Engineering, Imperial College, South Kensington Campus, London, SW7 2AZ, United Kingdom; Bullard Laboratories, Department of Earth Sciences, University of Cambridge, Cambridge, CB2 3EQ, United Kingdom 1-2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-67549146397&doi=10.1016%2fj.epsl.2009.04.033&partnerID=40&md5=12301d7d8c30da682b2d7ac3ed748a43 cited By 28 G.L. Christeson G.S. Collins J.V. Morgan S.P.S. Gulick P.J. Barton M.R. Warner article Sanford2009867 We investigated the groundwater system of the Chesapeake Bay impact structure by analyzing the pore-water chemistry in cores taken from a 1766-m-deep drill hole 10 km north of Cape Charles, Virginia. Pore water was extracted using high-speed centrifuges from over 100 cores sampled from a 1300 m section of the drill hole. The pore-water samples were analyzed for major cations and anions, stable isotopes of water and sulfate, dissolved and total carbon, and bioavailable iron. The results reveal a broad transition between freshwater and saline water from 100 to 500 m depth in the postimpact sediment section, and an underlying synimpact section that is almost entirely filled with brine. The presence of brine in the lowermost postimpact section and the trend in dissolved chloride with depth suggest a transport process dominated by molecular diffusion and slow, compaction-driven, upward flow. Major ion results indicate residual effects of diagenesis from heating, and a pre-impact origin for the brine. High levels of dissolved organic carbon (6-95 mg/L) and the distribution of electron acceptors indicate an environment that may be favorable for microbial activity throughout the drilled section. The concentration and extent of the brine is much greater than had previously been observed, suggesting that its occurrence may be common in the inner crater. However, groundwater-flow conditions in the structure may reduce the saltwater-intrusion hazard associated with the brine. © 2009 The Geological Society of America. 2009 English 00721077 10.1130/2009.2458(36) Special Paper of the Geological Society of America 458 Geological Society of America 867-890 U.S. Geological Survey, Mail Stop 926A, 12201 Sunrise Valley Drive, Reston, VA 20192, United States; Centre for Earth, Planetary, Space and Astronomical Research, Open University, Milton Keynes, MK7 6AA, United Kingdom Chemical analysis; Chlorine compounds; Dissolution; Groundwater; Groundwater flow; Hydrochemistry; Infill drilling; Organic carbon; Rock drills; Salt water intrusion; Sulfur compounds, Chesapeake bay impact structures; Dissolved organic carbon; Electron acceptor; Groundwater system; Microbial activities; Molecular diffusion; Pore-water chemistry; Stable isotopes of water, Saline water, cation; dissolved organic carbon; geological survey; groundwater flow; impact structure; microbial activity; microbial community; paleohydrology; porewater; saline intrusion; sediment core; stable isotope; sulfate; transport process; water chemistry; water resource, Chesapeake Bay; United States; Virginia https://www.scopus.com/inward/record.uri?eid=2-s2.0-74949100401&doi=10.1130%2f2009.2458%2836%29&partnerID=40&md5=4d823a7f8f1d692327d86e93d61e6d8d cited By 22 W.E. Sanford M.A. Voytek D.S. Powars B.F. Jones I.M. Cozzarelli C.S. Cockell R.P. Eganhouse article Riemann20091251 Thermobarometry and in situ U-Pb dating of zircon in texturally and petrologically defined positions are used to assess exhumation accompanied by fluid-enhanced retrogression of ultra high pressure (UHP) eclogite core samples from the Chinese Continental Scientific Drilling (CCSD) project. Eclogites from the CCSD project show discrete retrograde zones that can be attributed to exhumation processes. The retrogression from UHP eclogite to HP eclogite, amphibolite and finally greenschist facies conditions is fluid-induced. The occurrence of significant barium concentrations in two mica generations points to an external fluid source during retrogression. This Ba and F-bearing fluid mobilized zirconium from the eclogitic host, which was preferentially precipitated as overgrowths on pre-existing grains in the retrograde zone. Thermodynamic modelling with progressive addition of H2O to the bulk composition simulates the petrological development of the fluid-influenced retrograde zone. Growth of zircon precipitated from the fluid occurred between 730°-740 °C at 3.46 GPa and 700 °C at 1.4 GPa. LA-SF-ICPMS analyses point to a local onset of metasomatic zircon growth at 233.1 ± 5.3 Ma ongoing to 207.4 ± 1.6 Ma that is spatially limited to the retrograde zone. © 2009 E. Schweizerbart'sche Verlagsbuchhandlung. Article 2009 English 09351221 10.1127/0935-1221/2009/0021-2005 European Journal of Mineralogy 21 Gebruder Borntraeger Verlagsbuchhandlung 1251 – 1264 6 Binary alloys; Gasoline; Geochronology; Inductively coupled plasma mass spectrometry; Infill drilling; Metamorphic rocks; Mica; Barium concentrations; Continental scientific drillings; Eclogites; Retrogression; Thermodynamic modelling; U-Pb dating; Ultra high pressure (UHP); Ultra-high pressure metamorphisms; amphibolite; Chinese Continental Scientific Drilling Project; eclogite; exhumation; inductively coupled plasma method; mass spectrometry; petrology; ultrahigh pressure metamorphism; uranium-lead dating; zircon; Zircon https://www.scopus.com/inward/record.uri?eid=2-s2.0-77149148196&doi=10.1127%2f0935-1221%2f2009%2f0021-2005&partnerID=40&md5=6ba000b40d9741a5354eda148ce00121 Cited by: 9 Astrid Riemann Roland Oberhänsli Andreas Möller Axel Gerdes Zhigin Xu article Browning2009775 The Eyreville core holes provide the first continuously cored record of postimpact sequences from within the deepest part of the central Chesapeake Bay impact crater. We analyzed the upper Eocene to Pliocene postimpact sediments from the Eyreville A and C core holes for lithology (semiquantitative measurements of grain size and composition), sequence stratigraphy, and chronostratigraphy. Age is based primarily on Sr isotope stratigraphy supplemented by biostratigraphy (dinocysts, nannofossils, and planktonic foraminifers); age resolution is approximately ±0.5 Ma for early Miocene sequences and approximately ±1.0 Ma for younger and older sequences. Eocene-lower Miocene sequences are subtle, upper middle to lower upper Miocene sequences are more clearly distinguished, and upper Miocene- Pliocene sequences display a distinct facies pattern within sequences. We recognize two upper Eocene, two Oligocene, nine Miocene, three Pliocene, and one Pleistocene sequence and correlate them with those in New Jersey and Delaware. The upper Eocene through Pleistocene strata at Eyreville record changes from: (1) rapidly deposited, extremely fi ne-grained Eocene strata that probably represent two sequences deposited in a deep (>200 m) basin; to (2) highly dissected Oligocene (two very thin sequences) to lower Miocene (three thin sequences) with a long hiatus; to (3) a thick, rapidly deposited (43-73 m/Ma), very fi ne-grained, biosiliceous middle Miocene (16.5-14 Ma) section divided into three sequences (V5-V3) deposited in middle neritic paleoenvironments; to (4) a 4.5-Ma-long hiatus (12.8-8.3 Ma); to (5) sandy, shelly upper Miocene to Pliocene strata (8.3-2.0 Ma) divided into six sequences deposited in shelf and shoreface environments; and, last, to (6) a sandy middle Pleistocene paralic sequence (~400 ka). The Eyreville cores thus record the fi lling of a deep impact-generated basin where the timing of sequence boundaries is heavily infl uenced by eustasy. © 2009 The Geological Society of America. 2009 English 00721077 10.1130/2009.2458(33) Special Paper of the Geological Society of America 458 Geological Society of America 775-810 Department of Earth and Planetary Sciences, Rutgers University, Piscataway, NJ 08854, United States; Delaware Geological Survey, University of Delaware, DGS Building, 257 Academy Street, Newark, DE 19716, United States; U.S. Geological Survey, 926A National Center, Reston, VA 20192, United States; Department of Geology and Geophysics, Texas A and M University, College Station, TX 77843, United States Lithology, Chesapeake bay impact structures; Chronostratigraphy; Measurements of; Middle Pleistocene; Paleoenvironments; Pleistocene strata; Sequence boundary; Sequence stratigraphy, Stratigraphy, biostratigraphy; chronostratigraphy; deposition; Eocene; impact structure; lithology; Miocene; paleoenvironment; Pleistocene; Pliocene; sequence boundary; sequence stratigraphy; strontium isotope, Chesapeake Bay; Delaware; New Jersey; United States, Foraminifera https://www.scopus.com/inward/record.uri?eid=2-s2.0-74949114383&doi=10.1130%2f2009.2458%2833%29&partnerID=40&md5=1481ae772c6cd983df02981e4c329037 cited By 27 J.V. Browning K.G. Miller P.P. McLaughlin Jr. L.E. Edwards A.A. Kulpecz D.S. Powars B.S. Wade M.D. Feigenson J.D. Wright article Šafanda20099 Geothermal research of the Chicxulub impact structure on the Yucatan Peninsula, Mexico, included repeated temperature logs following 0.3-0.8, 15, 24, 34 and 50 months after shut-in of drilling operations at the 1.5 km deep Yaxcopoil-1 borehole. A gradual distortion of the linear temperature profile by a cold wave propagating downward from 145 m to 317 m was detected within the observational period of 49 months (March 2002-April 2006). The amplitude of the cold wave was increasing with depth and time in the range of 0.8-1.6 °C. As an explanation of this unusual phenomenon, the hypothesis of downward migration of a large volume of drilling mud, reported lost during drilling within the overlying and cooler highly porous and permeable karstic rocks, has been proposed. The thermal effects of the migrating fluid have been evaluated by solving numerically the heat conduction-convection equation in appropriate geothermal models. The best coincidence between the observed data and the simulations was yielded by the model of the drilling mud migrating as a large body. Parameters of this model are constrained by the measured temperature logs relatively tightly: (i) the vertical extent of the downward migrating fluid body is about 5-10 m, possibly increasing within the observational period of 49 months by a factor of 2; (ii) the horizontal extent of the body must be at least 15-20 m, i.e. by order(s) of magnitude larger than the diameter of the borehole; (iii) the average speed of the migration is about 5 metres per month and (iv) the fluid must migrate through a highly porous rock (80% porosity or more). This high porosity, which is necessary for the model to fit the observed data, and the observed relatively stable velocity of the migration indicate the existence of a well-developed system of interconnected cavities down to more than 300 m about 150 m more than the deepest cave system known in Yucatan yet. © 2009 Elsevier B.V. All rights reserved. 2009 10.1016/j.jhydrol.2009.03.023 Journal of Hydrology 372 9-16 Institute of Geophysics, Boční II/1401, 141 31 Praha, Czech Republic; Geophysical Institute, University of Karlsruhe, Hertzstrasse 16, 76187 Karlsruhe, Germany 1-4 https://www.scopus.com/inward/record.uri?eid=2-s2.0-65649099795&doi=10.1016%2fj.jhydrol.2009.03.023&partnerID=40&md5=205f7cf6e7f24ef232585d170ac84f2e cited By 3 J. Šafanda H. Wilhelm P. Heidinger V. Čermák article Zhang2009 We refined the three-dimensional (3-D) Vp, Vs and Vp/Vs models around the San Andreas Fault Observatory at Depth (SAFOD) site using a new double-difference (DD) seismic tomography code (tomoDDPS) that simultaneously solves for earthquake locations and all three velocity models using both absolute and differential P, S, and S-P times. This new method is able to provide a more robust Vp/Vs model than that from the original DD tomography code (tomoDD), obtained simply by dividing Vp by Vs. For the new inversion, waveform cross-correlation times for earthquakes from 2001 to 2002 were also used, in addition to arrival times from earthquakes and explosions in the region. The Vp values extracted from the model along the SAFOD trajectory match well with the borehole log data, providing in situ confirmation of our results. Similar to previous tomographic studies, the 3-D structure around Parkfield is dominated by the velocity contrast across the San Andreas Fault (SAF). In both the Vp and Vs models, there is a clear low-velocity zone as deep as 7 km along the SAF trace, compatible with the findings from fault zone guided waves. There is a high Vp/Vs anomaly zone on the southwest side of the SAF trace that is about 1-2 km wide and extends as deep as 4 km, which is interpreted to be due to fluids and fractures in the package of sedimentary rocks abutting the Salinian basement rock to the southwest. The relocated earthquakes align beneath the northeast edge of this high Vp/Vs zone. We carried out a 2-D correlation analysis for an existing resistivity model and the corresponding profiles through our model, yielding a classification that distinguishes several major lithologies. © 2009 by the American Geophysical Union. 2009 English 15252027 10.1029/2009GC002709 Geochemistry, Geophysics, Geosystems 10 Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, United States; Department of Geoscience, University of Wisconsin-Madison, Madison, WI 53706, USA, United States; U.S. Geological Survey, Denver, CO 80225, United States 11 https://www.scopus.com/inward/record.uri?eid=2-s2.0-72049100963&doi=10.1029%2f2009GC002709&partnerID=40&md5=1c1fa8213385ada6e5b5d4618a808a5e cited By 115 H. Zhang C. Thurber P. Bedrosian article Reimer2009195 Saline, 450-m-deep Lake Van (Eastern Anatolia, Turkey) is, with 576 km3, the third largest closed lake on Earth and its largest soda lake. In 1989 and 1990, we investigated the hydrochemistry of the lake's water column and of the tributary rivers. We also cored the Postglacial sediment column at various water depths. The sediment is varved throughout, allowing precise dating back to ca. 15 ka BP. Furthermore, lake terrace sediments provided a 606-year-long floating chronology of the Glacial high-stand of the lake dating to 21 cal. ka BP. The sediments were investigated for their general mineralogical composition, important geochemical parameters, and pore water chemistry as well. These data allow reconstructing the history of the lake level that has seen several regressions and transgressions since the high-stand at the end of the Last Glacial Maximum. Today, the lake is very alkaline, highly supersaturated with Ca-carbonate and has a salt content of about 22 g kg-1. In summer, the warmer epilimnion is diluted with river water and forms a stable surface layer. Depth of winter mixing differs from year to year but during time of investigation the lake was oxygenated down to its bottom. In general, the lake is characterized by an Na-CO3-Cl-(SO4)-chemistry that evolved from the continuous loss of calcium as carbonate and magnesium in the form of Mg-silica-rich mineral phases. The Mg cycle is closely related to that of silica which in turn is governed by the production and dissolution of diatoms as the dominant phytoplankton species in Lake Van. In addition to Ca and Mg, a mass balance approach based on the recent lake chemistry and river influx suggests a fractional loss of potassium, sodium, sulfur, and carbon in comparison to chloride in the compositional history of Lake Van. Within the last 3 ka, minor lake level changes seem to control the frequency of deep water renewal, the depth of stratification, and the redox state of the hypolimnion. Former major regressions are marked by Mg-carbonate occurrences in the otherwise Ca-carbonate dominated sediment record. Pore water data suggest that, subsequent to the major regression culminating at 10.7 ka BP, a brine layer formed in the deep basin that existed for about 7 ka. Final overturn of the lake, triggered by the last major regression starting at about 3.5 ka BP, may partly account for the relative depletion in sulfur and carbon due to rapid loss of accumulated gases. An even stronger desiccation phase is proposed for the time span between about 20 and 15 ka BP following the LGM, during which major salts could have been lost by precipitation of Na-carbonates and Na-sulfates. © The Author(s) 2008. 2009 English 13806165 10.1007/s10498-008-9049-9 Aquatic Geochemistry 15 195-222 Geowissenschaftliches Zentrum der Universität Göttingen, Goldschmidtstraße 3, 37077 Göttingen, Germany; Technische Universität Darmstadt, Institut für Angewandte Geowissenschaften, Schnittspahnstr. 9, Darmstadt 64287, Germany 1-2 desiccation; dissolution; Holocene; hydrochemistry; hydrogeochemistry; lake level; paleolimnology; porewater; water column; water depth, Eurasia; Lake Van; Turkey, Bacillariophyta https://www.scopus.com/inward/record.uri?eid=2-s2.0-64249140015&doi=10.1007%2fs10498-008-9049-9&partnerID=40&md5=e6fd8206d7484feee3f6594ce74d4c6a cited By 106 A. Reimer G. Landmann S. Kempe article Juschus20092155 Lake El'gygytgyn is situated in a 3·6 Myr old impact crater in North-eastern Siberia. Its sedimentary record probably represents the most complete archive of Pliocene and Quaternary climate change in the terrestrial Arctic. In order to investigate the influence of gravitational sediment transport on the pelagic sediment record in the lake centre, two sediment cores were recovered from the lower western lake slope. The cores penetrate a sub-recent mass movement deposit that was identified by 3·5 kHz echo sounding. In the proximal part of this deposit, deformed sediments reflect an initial debris flow characterized by limited sediment mixture. Above and in front of the debrite, a wide massive densite indicates a second stage with a liquefied dense flow. The mass movement event led to basal erosion of ca 1 m thick unconsolidated sediments along parts of its flow path. The event produced a suspension cloud, whose deposition led to the formation of a turbidite. The occurrence of the turbidite throughout the lake and the limited erosion at its base mainly suggest deposition by 'pelagic rain' following Stokes' Law. Very similar radiocarbon dates obtained in the sediments directly beneath and above the turbidite in the central lake confirm this interpretation. When applying the depositional model for the Late Quaternary sediment record of Lake El'gygytgyn, the recovered turbidites allow reconstruction of the frequency and temporal distribution of large mass movement events at the lake slopes. In total, 28 turbidites and related deposits were identified in two, 12·9 and 16·6 m long, sediment cores from the central lake area covering approximately 300 kyr. © 2009 The Authors. Journal compilation © 2009 International Association of Sedimentologists. 2009 English 00370746 10.1111/j.1365-3091.2009.01074.x Sedimentology 56 2155-2174 Institute for Geology and Mineralogy, University of Cologne, Zuelpicher Strasse 49a, D-50674 Cologne, Germany; Alfred Wegener Institute for Polar and Marine Research, Columbusstraße, D-27515 Bremerhaven, Germany 7 Basal erosion; Debris flows; Depositional models; Eastern Siberia; Flow path; Impact craters; Lake areas; Late Quaternary; Mass movement; Pelagic sediments; Pliocene; Quaternary climate; Radiocarbon dates; Sediment core; Sedimentary records; Siberian Arctic; Stokes' law; Temporal distribution; Turbidite; Unconsolidated sediment, Anoxic sediments; Climate change; Debris; Deposits; Erosion; Petroleum geology; Sediment transport; Sedimentation; Sedimentology, Lakes, climate variation; debris flow; deposition velocity; echo sounding; erosion rate; formation mechanism; lacustrine deposit; mass movement; paleoclimate; Pliocene-Pleistocene boundary; Quaternary; sediment core; sediment transport; Stokes formula; turbidite; unconsolidated medium, Chukchi; Elgygytgyn Lake; Russian Federation https://www.scopus.com/inward/record.uri?eid=2-s2.0-73249143083&doi=10.1111%2fj.1365-3091.2009.01074.x&partnerID=40&md5=1b5ef6542624aa9487178d4d60a93477 cited By 27 O. Juschus M. Melles A.C. Gebhardt F. Niessen article Claeys2009201 The NASA Deep Impact experiment has important implications to better understand cratering processes on planetary bodies and the production and evolution of ejecta. This man-made impact of a solid Cu body on the nucleus of a comet fills the large gap existing between data derived from small-scale cratering experiments and large-scale field or remote sensing observations of craters. DI thus complements hydrocode modeling of cratering processes. The majority of cratering studies focus on solid silicate-rich targets rather than on porous, poorly consolidated and/or volatile-rich materials. However, volatile targets are common in the Solar System. The lessons learned from the DI collision with comet 9P/Tempel not only clarify the composition and physical properties of the cometary nucleus, but also can shed light on cratering mechanisms and evolution of plume and ejecta. © 2009 Springer-Verlag Berlin Heidelberg. 2009 10.1007/978-3-540-76959-0_26 ESO Astrophysics Symposia 2009 201-211 Dept. of Geology, Vrije Universiteit Brussel, B-1050 Brussels, Belgium https://www.scopus.com/inward/record.uri?eid=2-s2.0-54849413005&doi=10.1007%2f978-3-540-76959-0_26&partnerID=40&md5=cf572ae318d3c3b11861315a895914fe cited By 0 P. Claeys conference Huang20091039 A new approach is developed to model 3D reservoirs that capture different scales of heterogeneities and simultaneously honor statistical features observed in the well logs. Our approach provides a platform to estimate rock physics properties at the well log scale and to study the behavior of waves in reservoirs with various scales of heterogeneities. The modeling algorithm is applied to the gas hydrate reservoir located in Mallik area, Northwestern Territory of Canada. We show that by using the Biot-Gassmann theory, the statistical parameters obtained from Mallik 5L-38 borehole logs, and the horizontal correlation length estimated from inverted acoustic impedance, the gas hydrate volume fraction is estimated to be 1.8% of a 500m by 500m by 226m rock volume. This represents approximately 167.5x10∧6 m∧3 of natural gas stored in hydrate bearing intervals under standard condition. We find that the degree of lateral heterogeneity play a significant role in assessing the amount of gas hydrates and thus more adequate lateral sampling is desired to constrain the resource assessment in the reservoir. Copyright 2009, European Association of Geoscientists and Engineers. 2009 English 9781615672363 71st European Association of Geoscientists and Engineers Conference and Exhibition 2009: Balancing Global Resources. Incorporating SPE EUROPEC 2009 2 Society of Petroleum Engineers 1039-1043 University of Toronto, Canada; Geological Survey of Canada, Canada Acoustic impedance; Engineering exhibitions; Hydration; Petroleum reservoir evaluation; Three dimensional; Well logging, Borehole logs; Correlation lengths; Different scale; Gas hydrate reservoir; Gassmann theory; Lateral heterogeneity; Multi-scale Modeling; New approaches; Reservoir heterogeneity; Resource assessments; Rock physics; Standard conditions; Statistical features; Statistical parameters; Well logs, Gas hydrates https://www.scopus.com/inward/record.uri?eid=2-s2.0-77649300297&partnerID=40&md5=f6a6b83246040d05c674d687e24cfe63 cited By 0 J.W. Huang G. Bellefleur B. Milkereit article Sun2009 No perfectly elastic medium exists in the earth. In an anelastic medium, seismic waves are distorted by attenuation and velocity dispersion. Velocity dispersion depends on the petrophysical properties of reservoir rocks, such as porosity, fractures, fluid mobility, and the scale of heterogeneities. However, velocity dispersion usually is neglected in seismic data processing partly because of the insufficiency of observations in the exploration seismic frequency band (∼5 through 200 Hz). The feasibility of determining velocity dispersion in this band is investigated. Four methods are used in measuring velocity dispersion from uncorrelated vibrator vertical seismic profile (VSP) data: the moving window crosscorrelation (MWCC) method, instantaneous phase method, time-frequency spectral decomposition method, and cross-spectrum method. The MWCC method is a new method that is satisfactorily robust, accurate, and efficient in measuring the frequency-dependent traveltime in uncorrelated vibrator records. The MWCC method is applied to the uncorrelated vibrator VSP data acquired in the Mallik gas hydrate research well. For the first time, continuous velocity dispersion is observed in the exploration seismic frequency band using uncorrelated vibrator VSP data. The observed velocity dispersion is fitted to a straight line with respect to log frequency to calculate Q. This provides an alternative method for Q measurement. © 2009 Society of Exploration Geophysicists. All rights reserved. 2009 English 00168033 10.1190/1.3068426 Geophysics 74 Society of Exploration Geophysicists WA113-WA122 University of Toronto, Department of Physics, Toronto, ON, Canada; University of Alberta, Department of Physics, Institute for Geophysical Research, Edmonton, AB, Canada 2 Data handling; Dispersion (waves); Gas hydrates; Petroleum prospecting; Petrophysics; Seismic waves; Seismology; Velocity; Vibrators, Frequency dependent; Instantaneous phase; Petrophysical properties; Seismic data processing; Seismic frequencies; Spectral decomposition methods; Velocity dispersion; Vertical seismic profiles, Seismic prospecting, accuracy assessment; conference proceeding; data processing; efficiency measurement; frequency analysis; frequency dependence; heterogeneity; observational method; seismic attenuation; seismic data; seismic velocity; seismic wave; wave dispersion https://www.scopus.com/inward/record.uri?eid=2-s2.0-63049125819&doi=10.1190%2f1.3068426&partnerID=40&md5=8814ea3823e54c6d81dcb88777f416bd cited By 36 L.F. Sun B. Milkereit article Shah2009195 We use magnetic susceptibility and remanent magnetization measurements of the Eyreville and Cape Charles cores in combination with new and previously collected magnetic field data in order to constrain structural features within the inner basin of the Chesapeake Bay impact structure. The Eyreville core shows the first evidence of several-hundred-meter-thick basement-derived megablocks that have been transported possibly kilometers from their pre-impact location. The magnetic anomaly map of the structure exhibits numerous short-wavelength (<2 km) variations that indicate the presence of magnetic sources within the crater fill. With core magnetic properties and seismic reflection and refraction results as constraints, forward models of the magnetic field show that these sources may represent basementderived megablocks that are a few hundred meters thick or melt bodies that are a few dozen meters thick. Larger-scale magnetic field properties suggest that these bodies overlie deeper, pre-impact basement contacts between materials with different magnetic properties such as gneiss and schist or gneiss and granite. The distribution of the short-wavelength magnetic anomalies in combination with observations of small-scale (1-2 mGal) gravity field variations suggest that basement-derived megablocks are preferentially distributed on the eastern side of the inner crater, not far from the Eyreville core, at depths of around 1-2 km. A scenario where additional basement-derived blocks between 2 and 3 km depth are distributed throughout the inner basin-and are composed of more magnetic materials, such as granite and schist, toward the east over a large-scale magnetic anomaly high and less magnetic materials, such as gneiss, toward the west where the magnetic anomaly is lower-provides a good model fi t to the observed magnetic anomalies in a manner that is consistent with both gravity and seismic-refraction data. © 2009 The Geological Society of America. 2009 English 00721077 10.1130/2009.2458(10) Special Paper of the Geological Society of America 458 Geological Society of America 195-208 U.S. Geological Survey, Denver Federal Center, MS 964, Bldg. 20, Denver, CO 80225, United States; U.S. Geological Survey, National Center, MS 954, 12201 Sunrise Valley Drive, Reston, VA 20192, United States; Institut für Angewandte Geowissenschaften, Universität Karlsruhe-Karlsruhe, Hertzstraße 16, Gebäude 6.36, 76187 Karlsruhe, Germany; Naval Research Laboratory, Marine Physics Branch Code 7421, 4555 Overlook Avenue SW, Washington, DC 20375, United States Buildings; Electromagnetic field effects; Granite; Magnetic materials; Magnetic susceptibility; Magnetization; Refraction; Seismology, Chesapeake bay impact structures; Magnetic anomalies; Magnetic field data; Remanent magnetization; Seismic reflections; Seismic refraction data; Short wavelengths; Structural feature, Structural properties, crater; gravity anomaly; magnetic anomaly; magnetic field; magnetic property; magnetic susceptibility; remanent magnetization; seismic reflection; seismic refraction, Chesapeake Bay; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-74949087715&doi=10.1130%2f2009.2458%2810%29&partnerID=40&md5=7a28d2346f7869dfc6776ec9c89ca872 cited By 12 A.K. Shah D.L. Daniels A. Kontny J. Brozena article Cockell2009941 Asteroid and comet impact events are known to cause profound disruption to surface ecosystems. The aseptic collection of samples throughout a 1.76-km-deep set of cores recovered from the deep subsurface of the Chesapeake Bay impact structure has allowed the study of the subsurface biosphere in a region disrupted by an impactor. Microbiological enumerations suggest the presence of three major microbiological zones. The upper zone (127-867 m) is characterized by a logarithmic decline in microbial abundance from the surface through the postimpact section of Miocene to Upper Eocene marine sediments and across the transition into the upper layers of the impact tsunami resurge sediments and sediment megablocks. In the middle zone (867-1397 m) microbial abundances are below detection. This zone is predominantly quartz sand, primarily composed of boulders and blocks, and it may have been mostly sterilized by the thermal pulse delivered during impact. No samples were collected from the large granite block (1096-1371 m). The lowest zone (below 1397 m) of increasing microbial abundance coincides with a region of heavily impact-fractured, hydraulically conductive suevite and fractured schist. These zones correspond to lithologies infl uenced by impact processes. Our results yield insights into the infl uence of impacts on the deep subsurface biosphere. © 2009 The Geological Society of America. 2009 English 00721077 10.1130/2009.2458(40) Special Paper of the Geological Society of America 458 Geological Society of America 941-950 Centre for Earth, Planetary Science and Astronomical Research, Open University, Milton Keynes, MK7 6AA, United Kingdom; U.S. Geological Survey, MS 430 12201 Sunrise Valley Drive, Reston, VA 20192, United States; Institute of Biological Sciences, Microbiology Section, Aarhus University, 8000 Aarhus C, Denmark; Carnegie Institute of Washington, 1530 P Street NW, Washington, DC 20005, United States Biospherics; Lithology; Submarine geology, Chesapeake Bay; Chesapeake bay impact structures; Impact craters; Impact process; Marine sediments; Microbial abundances; Subsurface biosphere; Surface ecosystems, Sediments, abundance; asteroid; biosphere; comet; crater; Eocene; hydraulic conductivity; impact structure; lithology; marine sediment; microbial activity; microbial community; microbiology; Miocene; schist; suevite, Chesapeake Bay; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-74949085356&doi=10.1130%2f2009.2458%2840%29&partnerID=40&md5=65803cf538c111668057a9c10f301c39 cited By 12 C.S. Cockell A.L. Gronstal M.A. Voytek J.D. Kirshtein K. Finster W.E. Sanford M. Glamoclija G.S. Gohn D.S. Powars J.W. Horton Jr. article Bourouis2009561 The Gulf of Corinth, in western-central Greece, is one of the fastest continental rifts in the world. In its western section near the city of Aigion, the previous work has outlined the existence of a shallow dipping seismogenic zone between 5 and 12 km. This seismic activity has been monitored with a network of 12 three-component stations for the period 2000-2007. Three, few months long, seismic swarms have been observed. They mobilize a complex structural fault system that associates both shallow dipping elements and subvertical structures with very different azimuths, some of which extend to depths greater than that of the shallow dipping zone. The swarm activity associates intensely active, short crises (a few days) with more quiescent periods. The long-term growth velocity of the seismically activated domains is compatible with a fluid diffusion process. Its characteristics are discussed in the context of the results from the 1000 m deep AIG10 well that intersects the Aigion Fault at 760 m. The vertical growth directions of the seismically activated volumes outline two different sources for the fluid and imply non-steady pressure conditions within the seismic domain. The diffusivity along the cataclastic zone of the faults is in the order of 1 m2 s-1, while faults act as hydraulic barrier in the direction perpendicular to their strike. If the vertical direction is a principal stress component, the high pore pressure values that must be reached to induce slip on the shallowly dipping planes can result only from transitory dynamic conditions. It is argued that the shallow dipping active seismic zone is only local and does not correspond to a 100 km scale decollement zone. We propose to associate the localization process with deep fluid fluxes that have progressively modified the local stress field and may be the cause for the quiescence of the West Heliki Fault presently observed. © 2009 The Authors, Journal compilation © 2009 RAS. Article 2009 English 1365246X 10.1111/j.1365-246X.2009.04148.x Geophysical Journal International 178 561 – 580 1 Eurasia; Europe; Greece; Gulf of Corinth; Ionian Sea; Mediterranean Sea; Southern Europe; backarc basin; earthquake swarm; fault zone; fluid-structure interaction; permeability; porosity; rheology; seismicity; stress field https://www.scopus.com/inward/record.uri?eid=2-s2.0-67650242309&doi=10.1111%2fj.1365-246X.2009.04148.x&partnerID=40&md5=5de6de9f138354c9e305f11aa8f648bf Cited by: 54; All Open Access, Bronze Open Access S. Bourouis Francois H. Cornet article Bulut2009 The North Anatolian Fault Zone (NAFZ) below the Sea of Marmara forms a "seismic gap" where a major earthquake is expected to occur in the near future. This segment of the fault lies between the 1912 Ganos and 1999 İzmit ruptures and is the only NAFZ segment that has not ruptured since 1766. To monitor the microseismic activity at the main fault branch offshore of Istanbul below the Çinarcik Basin, a permanent seismic array (PIRES) was installed on the two outermost Prince Islands, Yassiada and Sivriada, at a few kilometers distance to the fault. In addition, a temporary network of ocean bottom seismometers was deployed throughout the Çinarcik Basin. Slowness vectors are determined combining waveform cross correlation and P wave polarization. We jointly invert azimuth and traveltime observations for hypocenter determination and apply a bootstrap resampling technique to quantify the location precision. We observe seismicity rates of 20 events per month for M < 2.5 along the basin. The spatial distribution of hypocenters suggests that the two major fault branches bounding the depocenter below the Çinarcik Basin merge to one single master fault below ∼17 km depth. On the basis of a cross-correlation technique we group closely spaced earthquakes and determine composite focal mechanisms implementing recordings of surrounding permanent land stations. Fault plane solutions have a predominant right-lateral strike-slip mechanism, indicating that normal faulting along this part of the NAFZ plays a minor role. Toward the west we observe increasing components of thrust faulting. This supports the model of NW trending, dextral strike-slip motion along the northern and main branch of the NAFZ below the eastern Sea of Marmara. Copyright 2009 by the American Geophysical Union. 2009 English 21699313 10.1029/2008JB006244 Journal of Geophysical Research: Solid Earth 114 Blackwell Publishing Ltd Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences, Section 3.2, Geomechanics and Rheology, Telegrafenberg D424, D-14473 Potsdam, Germany; U.S. Geological Survey, MS 977, 345 Middlefield Road, Menlo Park, CA 94025, United States; Kandilli Observatory and Earthquake Research Institute, Boǧaziçi University, 34680, Çengelköy, Istanbul, Turkey 9 azimuth; depocenter; earthquake hypocenter; earthquake mechanism; earthquake rupture; fault geometry; fault zone; focal mechanism; observational method; P-wave; seismic tomography; seismicity; seismograph; spatial distribution; strike-slip fault; tectonic setting; travel time; waveform analysis, Anatolia; Eurasia; Istanbul [Turkey]; Sea of Marmara; Turkey https://www.scopus.com/inward/record.uri?eid=2-s2.0-72049131273&doi=10.1029%2f2008JB006244&partnerID=40&md5=75acb05f6c4b9b422b937adb48b0d64f cited By 45 F. Bulut M. Bohnhoff W.L. Ellsworth M. Aktar G. Dresen article Lu2009157 Based on field-investigated gas geochemistry and predecessors data such as the permafrost ground temperature, thermal gradients within/below the frozen layer, the modeling on gas hydrate formation conditions is conducted in the Qinghai-Tibet plateau permafrost. The modeled results show that the permafrost characteristics generally meet gas hydrate formation conditions in the study area. Gas composition, temperature-related permafrost parameters (e. g. permafrost thickness or its ground temperature and thermal gradients within / below the frozen layer) are the most important factors affecting gas hydrate occurrences, whose variance may cause the heterogeneity of gas hydrate occurrences in the study area. The most probable gas hydrate is the kind of hybrid of methane and weight hydrocarbon gases (ethane and propane). In the predicted gas hydrate locations, the upper gas hydrate occurrence depth may be around several ten to more than one hundred meters and the lower depth may range from several hundred meters to about one thousand meters and the thickness may reach several hundred meters. Compared with Canadian Mallik permafrost, the Qinghai-Tibet plateau permafrost has similar thermal gradients within / below the frozen layer and gas composition, except for relatively thinner permafrost, still suggesting great gas hydrate potentials. 2009 Chinese 00015733 Acta Geophysica Sinica 52 Science Press 157-168 Institute of Mineral Resources, CAGS, Beijing 100037, China; Departement de Geosciences Marines, IFREMER, Centre de Brest, Plouzané 29280, France; Strategic Research Center for Oil and Gas Resources, Ministry of Land and Resources, Beijing 100034, China; National Center for Geological Experiment and Test, Beijing 100037, China 1 frozen ground; gas hydrate; geochemistry; heterogeneity; permafrost; temperature gradient, Asia; China; Eurasia; Far East; Qinghai-Xizang Plateau https://www.scopus.com/inward/record.uri?eid=2-s2.0-67649289954&partnerID=40&md5=d3d7b3bdff7f5f835db9594bdbb2c34a cited By 26 Z.-Q. Lu N. Sultan C.-S. Jin Z. Rao X.-R. Luo B.-H. Wu Y.-H. Zhu article Artemieva2009768 In this paper we investigate the formation of the Cretaceous-Paleogene (K-Pg) boundary layer through numerical modeling. The K-Pg layer is widely agreed to be composed of meteoritic material and target rock from the Chicxulub impact site, that has been ejected around the globe and mixed with local material during final deposition. The observed composition and thickness of the K-Pg boundary layer changes with azimuth and distance from the impact site. We have run a suite of numerical simulations to investigate whether we can replicate the observational data, with a focus on the distal K-Pg layer and the impact glasses at proximal sites such as Beloc, Haiti. Previous models of the K-Pg ejecta have assumed an initial velocity distribution and tracked the ejecta to its final destination. Here, we attempt to model the entire process, from impact to the arrival of the ejecta around the globe. Our models replicate the observed ejecta thickness at proximal sites, and the modeled ejecta is composed of sediments and silicate basement rocks, in agreement with observational data. Models that use a 45° impact angle are able to replicate the total ejecta and iridium volume at distal sites, and the majority of the ejecta is composed of meteorite and target sediments. Sub-vertical impacts generate too little iridium, and oblique impacts of ≤30 degrees generate too much. However, in contrast to observations, models that involve ballistic transport of ejecta lead to ejecta thickness decreasing with increasing distance, and are unable to transport shocked minerals (quartz and zircon) from the Chicxulub basement rocks around the globe. We suggest that much of the K-Pg ejecta is transported non-ballistically, and that the most plausible mechanism is through re-distribution from a hot, expanding atmosphere. The results are important for future investigations of the environmental effects of the Chicxulub impact. © 2009 Elsevier Inc. All rights reserved. 2009 10.1016/j.icarus.2009.01.021 Icarus 201 768-780 Planetary Science Institute, 1700 E. Ft. Lowell, suite 106, Tucson, AZ 85719, United States; Institute for Dynamics of Geospheres, Leninsky pr., 38, Moscow, 119334, Russian Federation; Earth Science and Engineering, Imperial College London, South Kensington Campus, SW7 2AZ London, United Kingdom 2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-67349263403&doi=10.1016%2fj.icarus.2009.01.021&partnerID=40&md5=03d561871e5b314d4e6036ec00b6a3f8 cited By 74 N. Artemieva J. Morgan article Albrecht2009357 Ancient lakes are hotspots of biodiversity, often harboring a large number of endemic species that make them prime model systems for evolutionary biologists. Besides such well-recognized ancient or long-lived lakes as Baikal, Biwa, Ohrid, and Tanganyika, there are other potentially old and biodiverse lakes in the world with poorly specified ages and under-studied faunas. We here report on the mollusc fauna of one such lake, Lake Trichonis in continental Greece. This graben lake is situated in a highly tectonized area, characterized by karst features and probably of middle to late Pliocene origin. Lake Trichonis is deep, oligotrophic, and rich in such specific habitat types as macrophyte meadows, rocky shores and sublacustrine spring systems. Moreover, it is a hotspot of freshwater biodiversity in Greece, particularly in molluscs. After reviewing newly collected material and the published mollusc records, we found that at least 33 mollusc species occur in Lake Trichonis, with 24 gastropod and 9 bivalve species currently being recognized. This is 24% of the total freshwater mollusc diversity of Greece; 21% of the gastropods (five species) are endemic to Lake Trichonis. If the whole Trichonis Basin is considered, which also includes neighboring Lake Lysimachia, eight species (33%) of the total fauna appear to be endemic. Taking lake surface areas into account, the index of gastropod endemism of 0.442 (log Nendemic species/log Asurface area) for the Lake Trichonis Basin resembles on a world-wide scale values known for Lake Baikal, Russia, and Lake Biwa, Japan, and is only exceeded by Lake Ohrid, Macedonia/Albania, and ancient lakes of Sulawesi, Indonesia. Despite the limited knowledge about the lake's evolutionary history, the suggested age of origin, the palaeogeographical characteristics, and the potential timing of phylogenetic events reviewed here support the presumed status of Lake Trichonis as an ancient lake. From a conservational standpoint, more research, management and conservation efforts are necessary because ancient lakes are among the most vulnerable and threatened ecosystems on earth. Effects of human-induced environmental change are already noticeable in Lake Trichonis. Recognition of Lake Trichonis as a unique system with an unusually high biodiversity may help promoting conservation efforts. Article 2009 English 00762997 10.4002/040.051.0209 Malacologia 51 357 – 375 2 Bivalvia; Gastropoda; Lysimachia; Mollusca https://www.scopus.com/inward/record.uri?eid=2-s2.0-77149157015&doi=10.4002%2f040.051.0209&partnerID=40&md5=39248899177232ff25d3ac38cca098de Cited by: 32 Christian Albrecht Torsten Hauffe Kirstin Schreiber Sasho Trajanovski Thomas Wilke article Rostad2009891 Pore waters from the Chesapeake Bay impact structure cores recovered at Eyreville Farm, Northampton County, Virginia, were analyzed to characterize the dissolved organic carbon. After squeezing or centrifuging, a small volume of pore water, 100 μL, was taken for analysis by electrospray ionization-mass spectrometry. Porewater samples were analyzed directly without filtration or fractionation, in positive and negative mode, for polar organic compounds. Spectra in both modes were dominated by low-molecular-weight ions. Negative mode had clusters of ions differing by -60 daltons, possibly due to increasing concentrations of inorganic salts. The numberaverage molecular weight and weight-average molecular weight values for the pore waters from the Chesapeake Bay impact structure are higher than those reported for other aquatic sources of natural dissolved organic carbon as determined by electrospray ionization-mass spectrometry. In order to address the question of whether drilling mud fluids may have contaminated the pore waters during sample collection, spectra from the pore waters were compared to spectra from drilling mud fluids. Ions indicative of drilling mud fluids were not found in spectra from the pore waters, indicating there was no detectable contamination, and highlighting the usefulness of this analytical technique for detecting potential contamination during sample collection. © 2009 The Geological Society of America. 2009 English 00721077 10.1130/2009.2458(37) Special Paper of the Geological Society of America 458 Geological Society of America 891-903 U.S. Geological Survey, Box 25046, Building 95 MS 408, Denver Federal Center, Denver, CO 80225, United States; U.S. Geological Survey, 12201 Sunrise Valley Drive, MS 431, Reston, VA 20192, United States Boreholes; Dissolution; Electrospray ionization; Infill drilling; Ions; Mass spectrometry; Molecular weight; Mud logging; Organic carbon; Stream flow; Water, Chesapeake bay impact structures; Dissolved organic carbon; Electrospray ionization mass spectrometry; Inorganic salts; Low molecular weight; Polar organic compounds; Sample collection; Weight-average molecular weight, Drilling fluids, analytical method; detection method; dissolved organic carbon; drilling fluid; fractionation; impact structure; ionization; mass spectrometry; organic compound; porewater, Chesapeake Bay; United States; Virginia https://www.scopus.com/inward/record.uri?eid=2-s2.0-84874996887&doi=10.1130%2f2009.2458%2837%29&partnerID=40&md5=ce3250ff23a274a01b7ff7d6e20db4bf cited By 5 C.E. Rostad W.E. Sanford article Cermak2009131 For better understanding of temperature state in the subsurface, temperature-depth logs can be suitably completed by high-resolution long-run temperature-time monitoring at selected depths. The results of temperature monitoring at three depth levels in borehole Yaxcopoil-1, Chicxulub impact structure, Mexico (April/May 2006) proved that even when a borehole is in "fully" stabilized conditions, temperature may exhibit certain unrest resembling irregular oscillations in the order of hundredths or (in the extreme case) even first tenths of degree. Two novel methods for detection of the weak fingerprints of stable periodic components in long noisy records, namely the RQI (Recurrence Quantification Interval) analysis and the HiCum (Histograms Cumulation) were used to isolate the constituents with tidal periodicities from temperature oscillations measured in borehole Yaxcopoil-1. Both analyses revealed that temperature series contain perceptible tidal component. The field data were correlated with the simulated synthetic tides. The comparison of staked HiCum records for the theoretical gravity tide and monitored temperature shows significant positive linear correlation between both variables. There is a small lag between two signals corresponding to ~ 25 min phase difference. © 2009 Elsevier B.V. All rights reserved. 2009 10.1016/j.epsl.2009.03.009 Earth and Planetary Science Letters 282 131-139 Institute of Geophysics, Academy of Sciences of the Czech Republic, Praha, Czech Republic; Geophys. and Environ. Physics Res. Group, Hung. Acad. Sci., Budapest, Hungary 1-4 https://www.scopus.com/inward/record.uri?eid=2-s2.0-67349136481&doi=10.1016%2fj.epsl.2009.03.009&partnerID=40&md5=bb0c25effce7b98ddbc7992ee86222d9 cited By 2 V. Čermák L. Bodri J. Šafanda article Larsen2009699 In this study, we extend the knowledge of postimpact alteration processes through an investigation of mineralogy and petrology of 24 samples from the Exmore Formation and sedimentary megablock intervals in the Eyreville borehole within the Chesapeake Bay impact structure and comparisons to similar studies of cored intervals of the Cape Charles borehole. The bulk mineralogical studies reveal quartz, feldspars (microcline and albite), muscovite, smectite-vermiculite clays, and kaolinite with variable quantities of pyrite, zeolites, calcite, and chlorite. X-ray diffraction analysis of the clay (<2 μm) fraction of samples indicates that the clays are dominated by expandable clays with lesser quantities of illite, kaolinite, glauconite, and mixed- layered clays. The expandable clays include smectite, vermiculite, and smectite-vermiculite intergrade varieties; illite interlayering is minimal (generally, <10% illite layers). Thin section and scanning electron microscope petrography in the Exmore breccia show evidence for extensive authigenic expandable clay in the matrix and dispersed pyrite lepispheres and fine calcite rhombs. Grain alteration includes feldspar dissolution and albitization, glauconite recrystallization, and dissolution and expandable-clay replacement of micas. Taken together, the results indicate that low-temperature alteration (maximum temperatures 60-80 °C) is prevalent in the sedimentary clast-rich intervals in the Eyreville cores, and the maximum effects are observed between 600 and 970 m depth. In comparison, the Exmore Formation from the Cape Charles borehole, 8 km to the southwest and overlying the central peak of the inner crater, shows more advanced authigenesis with Fe-rich chlorite, common quartz overgrowths, and mixed-layered illite-smectite clay with as much as 20% interlayered illite. A low-temperature hydrothermal mineral assemblage is documented in suevite and crystalline-clast breccia at depths of 725-820 m in the Cape Charles borehole. The fine-grained clastic target material and contained seawater are argued to have limited initial target melting and initial crater-floor temperatures in the Chesapeake Bay impact structure to an even greater degree than that of other marine craters targeted in consolidated sedimentary substrates. Subsequent hydrothermal circulation was confined to the central uplift and neighboring fractured zones, whereas alteration in the overlying sedimentary breccias involved conductive heat flow, reaction with hypersaline pore fluids, and minor fluid flow into more porous, permeable sedimentary blocks adjacent to the central uplift. © 2009 The Geological Society of America. 2009 English 00721077 10.1130/2009.2458(30) Special Paper of the Geological Society of America 458 Geological Society of America 699-721 Department of Earth Sciences, University of Memphis, Memphis, TN 38152, United States Boreholes; Calcite; Dissolution; Feldspar; Flow of fluids; Kaolinite; Mica; Pyrites; Quartz; Rocks; Scanning electron microscopy; Sedimentology; Silicate minerals; Temperature; X ray powder diffraction; Zeolites, Chesapeake bay impact structures; Feldspar dissolution; Hydrothermal circulation; Hydrothermal mineral assemblages; Low temperature alteration; Low temperatures; Maximum temperature; Sedimentary substrates, Clay alteration, albitization; breccia; dissolution; feldspar; hydrothermal activity; hydrothermal alteration; hydrothermal system; impact structure; kaolinite; mineralogy; muscovite; petrography; quartz; recrystallization; research program; sedimentary petrology; smectite; vermiculite, Chesapeake Bay; United States, Calluna vulgaris; Micas https://www.scopus.com/inward/record.uri?eid=2-s2.0-74949114717&doi=10.1130%2f2009.2458%2830%29&partnerID=40&md5=84830b590c51f1bd871febf0271f576c cited By 7 D. Larsen E.C. Stephens V.B. Zivkovic article Jin20091901 Sediments in Lake Qinghai archive important information about past environmental changes. In order to faithfully interpret the sediment records and constrain the elemental cycles, it is critical to trace various sources of sediments in the lake. The results show that the elemental input-output budgets are imbalanced for most major elements between riverine fluxes and mass accumulation rate (MAR) of Lake Qinghai sediments. A realistic model must include contributions of dry/wet atmospheric deposition that allow the major element mass balance for the lake to be defined. The budget estimation is based on mass balances of Si and Al, which are relatively immobile and carried to the lake via particulate forms. Estimated annual budget of dry atmospheric deposition is ∼1.3 ± 0.3 × 103 kt/a (accounting for ∼65% of the total inputs) to the lake sediments, assuming local loess within the catchment as a candidate for dry atmospheric deposition to the lake. The resultant flux of 300 ± 45 g/m2/a falls within the flux average of the desert area (400 g/m2/a) and the loess plateau (250 g/m2/a), consistent with the geographical setting of Lake Qinghai. The role of atmospheric deposition would be more significant if wet deposition via rainfall and snow were taken into account. This highlights the potential importance of dust as a significant source for sediment preservation flux for other catchments worldwide. The results also indicate that nearly all Ca input was preserved in the lake sediments under modern conditions, consistent with Ca2+ supersaturation of the lake water. © 2009 Elsevier Ltd. All rights reserved. Article 2009 English 08832927 10.1016/j.apgeochem.2009.07.003 Applied Geochemistry 24 1901 – 1907 10 Asia; China; Eurasia; Far East; Qinghai; Qinghai Lake; Qinghai-Xizang Plateau; Atmospheric chemistry; Atmospherics; Budget control; Calcium; Catchments; Deposition; Meteorological problems; Patient monitoring; Runoff; Sedimentology; Annual budget; Atmospheric depositions; Desert area; Environmental change; Input-output; Lake sediments; Lake waters; Loess Plateau; Major elements; Mass accumulation rates; Mass balance; Realistic model; Riverine flux; Tibetan Plateau; Wet deposition; atmospheric deposition; environmental change; geochemistry; lacustrine deposit; mass balance; Lakes https://www.scopus.com/inward/record.uri?eid=2-s2.0-70349186512&doi=10.1016%2fj.apgeochem.2009.07.003&partnerID=40&md5=d5bdf143864545b09dafe99027a8cbc6 Cited by: 32 Zhangdong Jin Chen-Feng You Jimin Yu article Schulte2009839 A multidisciplinary investigation of the Eocene-Oligocene transition in the International Continental Scientific Drilling Program (ICDP)-U.S. Geological Survey (USGS) Eyreville core from the Chesapeake Bay impact basin was conducted in order to document environmental changes and sequence stratigraphic setting. Planktonic foraminifera and calcareous nannofossil biostratigraphy indicate that the Eyreville core includes an expanded upper Eocene (Biozones E15 to E16 and NP19/20 to NP21, respectively) and a condensed Oligocene-Miocene (NP24-NN1) sedimentary sequence. The Eocene-Oligocene contact corresponds to a =3-Ma-long hiatus. Eocene- Oligocene sedimentation is dominated by great diversity and varying amounts of detrital and authigenic minerals. Four sedimentary intervals are identified by lithology and mineral content: (1) A 30-m-thick, smectite- and illite-rich interval directly overlies the Exmore Formation, suggesting long-term reworking of impact debris within the Chesapeake Bay impact structure. (2) Subsequently, an increase in kaolinite content suggests erosion from soils developed during late Eocene warm and humid climate in agreement with data derived from other Atlantic sites. However, the kaolinite increase may also be explained by change to a predominant sediment input from outside the Chesapeake Bay impact structure caused by progradation of more proximal facies belts during the highstand systems tract of the late Eocene sequence E10.Spectral analysis based on gamma-ray and magnetic susceptibility logs suggests infl uence of 1.2 Ma low-amplitude oscillation of the obliquity period during the late Eocene. (3) During the latest Eocene (Biozones NP21 and E16), several lithological contacts (clay to clayey silt) occur concomitant with a prominent change in the mineralogical composition with illite as a major component: This lithological change starts close to the Biozone NP19/20-NP21 boundary and may correspond to sequence boundary E10-E11 as observed in other northwest Atlantic margin sections. It could result from a shift to more distal depositional environments and condensed sedimentation during maximum fl ooding, rather than refl ecting a climatic change in the hinterland. The distinct 1% increase of the oxygen isotopes may correspond to the short-term latest Eocene "precursor isotope event." (4) The abrupt increase of sediment grainsize, carbonate content, and abundance of authigenic minerals (glauconite) across the major unconformity that separates Eocene from Oligocene sediments in the Eyreville core refl ects deposition in shallower settings associated with erosion, winnowing, and reworking. Sediments within the central crater were affected by the rapid eustatic sea-level changes associated with the greenhouse-icehouse transition, as well as by an abrupt major uplift event and possibly enhanced current activity on the northwestern Atlantic margin. © 2009 The Geological Society of America. 2009 English 00721077 10.1130/2009.2458(35) Special Paper of the Geological Society of America 458 Geological Society of America 839-865 GeoZentrum Nordbayern, Universität Erlangen, D-91054 Erlangen, Germany; Department of Earth and Planetary Sciences, Rutgers University, Piscataway, NJ 08901, United States; Department of Geology and Geophysics, Texas A and M University, College Station, TX 77843-3115, United States; Geologisches Institut der Universität Karlsruhe, Strukturgeologie und Tektonophysik, D-76187 Karlsruhe, Germany; U.S. Geological Survey, 926A National Center, Reston, VA 20192, United States Deposition; Erosion; Gamma rays; Infill drilling; Isotopes; Kaolinite; Lithology; Magnetic susceptibility; Mica; Sea level; Sedimentology; Stratigraphy, Chesapeake bay impact structures; Continental scientific drillings; Depositional environment; Highstand systems tract; Mineralogical compositions; Planktonic foraminifera; U.s. geological surveys; Warm and humid climates, Sediments, biostratigraphy; depositional environment; Eocene-Oligocene boundary; eustacy; geological survey; impact structure; lithology; paleoclimate; progradation; sea level change; sedimentary sequence; sedimentation; sequence boundary; sequence stratigraphy; systems tract, Atlantic Ocean; Atlantic Ocean (West); Chesapeake Bay; United States, Foraminifera https://www.scopus.com/inward/record.uri?eid=2-s2.0-74949144241&doi=10.1130%2f2009.2458%2835%29&partnerID=40&md5=052db37a4ba252be566f77790bcfb9f1 cited By 9 P. Schulte B.S. Wade A. Kontny J.M. Self-Trail article Wu2009308 The Upper Cretaceous Qingshankou Formation (K2qn) in the Songliao Basin (SLB) of Northeast China consists of up to 550 m thick, lacustrine mudstone and shale that constitute one of the most important source rocks of the Daqing oil field. A high-resolution cyclostratigraphic analysis of the natural gamma-ray logging from 10 wells of the Qingshankou Formation (K2qn) reveals orbital cycles of precession (20 ka), obliquity (40 ka) and eccentricity (100 ka and 405 ka), providing strong evidence for astronomically driven climate changes in the Late Cretaceous terrestrial environments. Floating astronomical time scales (ATS) are established for all sections, which demonstrate variable durations of K2qn across the basin (1.09 Ma-5.20 Ma) and strong diachroneity of the lacustrine strata. Four periods of high depositional rates can be identified in the central parts of the basin, possibly recording deposition during times of sustained wet climate and high chemical weathering. An ATS established from well M206 in the central depression zone of the basin, where the most complete and stable Milankovitch cycles are present, suggests that the maximum duration of the K2qn is 5.20 Ma (from 94.27 Ma to 89.07 Ma; Late Cenomanian to Early Coniacian). The lacustrine anoxic event 1 (LAE1) at the Cenomanian-Turonian boundary lasted ~ 210-310 ka, during which the most prolific petroleum source rocks in SLB were deposited. The onset (~ 94.21-94.18 Ma) and duration (~ 210-310 Ka) of LAE1 in SLB are comparable to those of the oceanic anoxic event 2 (OAE2; onset at 94.21 Ma and duration of ~ 320-900 ka), suggesting that the same trigger mechanism, such as increased atmospheric CO2 from large-scale igneous activity, may have initiated high primary productivity and organic carbon burial in both marine and terrestrial systems. © 2008 Elsevier B.V. All rights reserved. 2009 English 0012821X 10.1016/j.epsl.2008.12.016 Earth and Planetary Science Letters 278 308-323 State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Beijing, 100083, China; School of Marine Science, China University of Geosciences, Beijing, 100083, China; Department of Geoscience, University of Nevada, Las Vegas, NV 89154-4010, United States; Exploration and Development Research Institute, Daqing Oil Field Corporation Ltd., Daqing, Heilongjiang 163712, China 3-4 astronomical time scale (ATS); lacustrine anoxic event 1 (LAE1); Late Cretaceous; Milankovitch cycles; Songliao Basin, Astrophysics; Climate change; Fire hazards; Gamma rays; Oil fields; Oil shale; Organic carbon; Photosynthesis; Radioactivity logging; Shale oil; Stratigraphy; Weathering, Oil well logging, climate change; Cretaceous; cyclostratigraphy; Milankovitch cycle; mudstone; organic carbon; paleoclimate; source rock, Asia; China; Eurasia; Far East; Songliao Basin, Coniacian https://www.scopus.com/inward/record.uri?eid=2-s2.0-60649101797&doi=10.1016%2fj.epsl.2008.12.016&partnerID=40&md5=7e01a1e9e856acaea0aa183dc175a95f cited By 107 H. Wu S. Zhang G. Jiang Q. Huang article Zolitschka200929 Article 2009 10.2204/iodp.sd.8.04.2009 Scientific Drilling 29 – 34 8 https://www.scopus.com/inward/record.uri?eid=2-s2.0-78651552433&doi=10.2204%2fiodp.sd.8.04.2009&partnerID=40&md5=c3f037244d233387fecd967253117577 Cited by: 26; All Open Access, Gold Open Access, Green Open Access Bernd Zolitschka Flavio Anselmetti Daniel Ariztegui Hugo Corbella Christian Ohlendorf Frank Schäbitz article FerrellJr.2009723 Core descriptions, thin-section analyses, and X-ray powder diffraction analyses of whole-rock samples and clay-sized fractions were employed to interpret the sedimentology and mineralogy of synimpact Exmore beds and the overlying Chickahominy Formation. This study attempts to explain the origin and postdepositional alteration of materials in the Eyreville core from the central zone of the Chesapeake Bay impact crater. Samples were obtained from eight zones extending from core depths of 435 to 1471 m, with emphasis on the interval from 435 to 455 m, representing the upper Exmore beds and the lower Chickahominy Formation. Qualitative clay mineral determinations were aided by peak decomposition procedures to unravel overlapping diffraction bands, and quantifi cation was accomplished by least squares matching of actual and computed patterns. The major facies in approximate ascending order are suevite breccias, poorly sorted conglomerate and sandstone, and upward-fi ning glauconitic sandstone within the Exmore beds followed by parallel laminated sandy siltstone and claystone in the Chickahominy Formation. They all contain clay minerals (mica, smectites, and some serpentine, kaolinite, and chlorite) plus quartz and feldspar. Heulandite, pyrite, calcite, and disordered silica (partly representing nanofossils and microfossils) are present in the Chickahominy Formation. The boundary beds (upper 7 m) of the Exmore beds have higher clay contents but fewer varieties of expandable clay minerals than in the Chickahominy Formation. The Exmore beds are enriched in reworked glauconite, but there are no indications of heulandite, calcite, disordered silica, or pyrite, except in the very top of the 7-m-thick boundary bed interval. The clay fractions of the Eyreville materials are dominated by different species of expanding clay minerals (smectite, fi ne and coarsely crystalline nontronite, and fi ne and coarsely crystalline smectite-illite mixed-layered clay minerals), but dioctahedral mica and illite are also present. Amorphous material and minor amounts of quartz,chlorite, and mixed-layered smectite (0.95)/iron-rich illite (0.05) are common. The abundance of the clays in most intervals is highly variable due to the chaotic assemblage of sediments and crystalline materials from diverse sources. The boundary beds are dominated by a single smectitic mineral, nontronite, which is assumed to be the principal product of melt glass alteration. Amorphous material (melt glass) and nontronite are calculated to represent 13 vol% and 13-19 vol% of the sediments in this interval, respectively. Grain size, or clast size, has a major infl uence on mineralogical variability, i.e., when grain size (clast size) is large, the mineral content of adjacent samples is highly variable. © 2009 The Geological Society of America. 2009 English 00721077 10.1130/2009.2458(31) Special Paper of the Geological Society of America 458 Geological Society of America 723-746 Department of Geology and Geophysics, Louisiana State University, Baton Rouge, LA 70803, United States; Department of Geosciences, University of Oslo, P.O. Box 1047, Blindern, NO 0316, Oslo, Norway Calcite; Crystalline materials; Diffraction; Feldspar; Glass; Grain size and shape; Kaolinite; Mica; Pyrites; Quartz; Sandstone; Sediments; Serpentine; Silicate minerals; X ray powder diffraction; Zeolites, Chesapeake bay impact structures; Clay-sized fractions; Diffraction bands; Disordered silicas; Glass alteration; Layered clay minerals; Least-squares matching; Quantifi cations, Core samples, clay mineral; depositional sequence; facies; glauconite; grain size; illite; impact structure; least squares method; mineral alteration; mineralogy; qualitative analysis; sedimentology; X-ray diffraction, Chesapeake Bay; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-74949110811&doi=10.1130%2f2009.2458%2831%29&partnerID=40&md5=1a404644b1c3f1ed071b52e5b35c26b0 cited By 19 R.E. Ferrell Jr. H. Dypvik article Wittmann2009349 The International Continental Scientific Drilling Program (ICDP)-U.S. Geological Survey (USGS) Eyreville boreholes through the annular moat of the Chesapeake Bay crater recovered polymict impact breccias and associated rocks from the depth range of 1397-1551 m. These rocks record cratering processes before burial beneath resurge deposits. Quantitative analyses of clast sizes, matrix contents, and distribution of impact melt reveal a shock metamorphic gradient in these impactites. The reason for the low estimated quantity of impact melt in the crater (̃10 km3) remains elusive. Possible causes may relate to increased excavation efficiency due to a high ratio of water column and sedimentary target to depth of excavation, an oblique impact, or a buried melt sheet at depth. A plausible petrogenetic scenario consists of a lower blockrich section that slumped from an outer region of the transient cavity into the annular moat ̃1.5 min after impact. This blocky debris was mixed with the remains of the excavation fl ow, which contained a pod of melt entrained in ground-surge debris on top. Subsequently, melt-rich suevites were emplaced that record interaction of the expanding ejecta plume with fallback material related to the evolving central uplift. A clast-rich impact melt rock that likely shed off the central uplift covers these suevites. Incipient collapse of the ejecta plume is recorded in the uppermost subunit, but the arrival of resurge fl ow terminated its continuous deposition ̃6-8 min after impact. Limited thermal annealing allowed preservation of glassy melt and high-pressure polymorphs. Mild hydrothermal overprint in the central crater was likely driven by the structural uplift of ̃100 °C warmer basement rocks. © 2009 The Geological Society of America. 2009 English 00721077 10.1130/2009.2458(16) Special Paper of the Geological Society of America 458 Geological Society of America 349-376 Lunar and Planetary Institute, 3600 Bay Area Boulevard, Houston, TX 77058, United States; Museum für Naturkunde-Leibniz Institute, Humboldt University Berlin, Invalidenstrasse 43, 10115 Berlin, Germany Boreholes; Debris; Excavation; Infill drilling; Structural geology, Basement rocks; Continental scientific drillings; Continuous deposition; High-pressure polymorph; Oblique impact; Thermal-annealing; Transient cavities; U.s. geological surveys, Rocks, crater; drilling; impact structure; impactite; marine sediment; petrogenesis; suevite, Chesapeake Bay; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-74949108058&doi=10.1130%2f2009.2458%2816%29&partnerID=40&md5=0961170ceac9858e8ce5a69c92465198 cited By 28 A. Wittmann W.U. Reimold R.T. Schmitt L. Hecht T. Kenkmann article Wittmann2009349 The International Continental Scientific Drilling Program (ICDP)-U.S. Geological Survey (USGS) Eyreville boreholes through the annular moat of the Chesapeake Bay crater recovered polymict impact breccias and associated rocks from the depth range of 1397-1551 m. These rocks record cratering processes before burial beneath resurge deposits. Quantitative analyses of clast sizes, matrix contents, and distribution of impact melt reveal a shock metamorphic gradient in these impactites. The reason for the low estimated quantity of impact melt in the crater (̃10 km3) remains elusive. Possible causes may relate to increased excavation efficiency due to a high ratio of water column and sedimentary target to depth of excavation, an oblique impact, or a buried melt sheet at depth. A plausible petrogenetic scenario consists of a lower blockrich section that slumped from an outer region of the transient cavity into the annular moat ̃1.5 min after impact. This blocky debris was mixed with the remains of the excavation fl ow, which contained a pod of melt entrained in ground-surge debris on top. Subsequently, melt-rich suevites were emplaced that record interaction of the expanding ejecta plume with fallback material related to the evolving central uplift. A clast-rich impact melt rock that likely shed off the central uplift covers these suevites. Incipient collapse of the ejecta plume is recorded in the uppermost subunit, but the arrival of resurge fl ow terminated its continuous deposition ̃6-8 min after impact. Limited thermal annealing allowed preservation of glassy melt and high-pressure polymorphs. Mild hydrothermal overprint in the central crater was likely driven by the structural uplift of ̃100 °C warmer basement rocks. © 2009 The Geological Society of America. 2009 10.1130/2009.2458(16) Special Paper of the Geological Society of America 458 349-376 Lunar and Planetary Institute, 3600 Bay Area Boulevard, Houston, TX 77058, United States; Museum für Naturkunde-Leibniz Institute, Humboldt University Berlin, Invalidenstrasse 43, 10115 Berlin, Germany https://www.scopus.com/inward/record.uri?eid=2-s2.0-74949108058&doi=10.1130%2f2009.2458%2816%29&partnerID=40&md5=0961170ceac9858e8ce5a69c92465198 cited By 28 A. Wittmann W.U. Reimold R.T. Schmitt L. Hecht T. Kenkmann article Zhang2009 We apply a three-dimensional (3D) generalized Radon transform (GRT) to scattered P-waves from 575 local earthquakes recorded at 68 temporary network stations for passive-source imaging of (near-vertical) structures close to the San Andreas Fault Observatory at Depth (SAFOD) site. The GRT image profiles through or close by the SAFOD site reveal near-vertical reflectors close to the fault zone as well as in the granite to the southwest and the Franciscan mélange to the northeast of the main fault. Although slightly lower in resolution, these structures are generally similar to features in 2D images produced with steep-dip prestack seismic migration of data from active source seismic reflection and refraction surveys. Our GRT images, however, also reveal several vertical reflectors to the northeast of the SAF that do not appear in the migration images but which are consistent with local geology. These results suggest that in a seismically active area, inverse scattering of earthquake data (for instance with the GRT) can be a viable and, in 3D, economic alternative to an active source survey. Copyright 2009 by the American Geophysical Union. 2009 English 00948276 10.1029/2009GL040372 Geophysical Research Letters 36 Department of Geoscience, University of Wisconsin-Madison, 1215 West Dayton St., Madison, WI 53706, United States; Earth Resources Laboratory, Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, MA 02139, United States; Department of Earth and Atmospheric Sciences, Saint Louis University, 3507 Laclede Ave., Saint Louis, MO 63108, United States 23 2D images; Active area; California; Earthquake data; Fault zone; Generalized radon transform; Image profile; Inverse scattering; P-waves; Prestack; San Andreas Fault; Seismic migration; Seismic reflections; Seismic waveforms; Source imaging; Temporary networks; Three-dimensional (3D), Earthquakes; Radon; Reflection; Seismic waves; Surveys, Three dimensional, data inversion; earthquake event; fault zone; imaging method; P-wave; prestack migration; Radon transform; seismic migration; seismic reflection; three-dimensional modeling; wave scattering; waveform analysis, California; North America; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-72049121177&doi=10.1029%2f2009GL040372&partnerID=40&md5=0a7771d70165d9f06407f0e6c0dc93ce cited By 20 H. Zhang P. Wang R.D. Van Der Hilst M.N. Toksoz C. Thurber L. Zhu article Trauth2009399 We analyzed published records of terrigenous dust flux from marine sediments off subtropical West Africa, the eastern Mediterranean Sea, and the Arabian Sea, and lake records from East Africa using statistical methods to detect trends, rhythms and events in Plio-Pleistocene African climate. The critical reassessment of the environmental significance of dust flux and lake records removes the apparent inconsistencies between marine vs. terrestrial records of African climate variability. Based on these results, major steps in mammalian and hominin evolution occurred during episodes of a wetter, but highly variable climate largely controlled by orbitally induced insolation changes in the low latitudes. © 2008 Elsevier Ltd. All rights reserved. Article 2009 English 02773791 10.1016/j.quascirev.2008.11.003 Quaternary Science Reviews 28 399 – 411 5-6 Africa; Sub-Saharan Africa; West Africa; Mammalia; Climatology; Mammals; Salinity measurement; Submarine geology; climate variation; dust; marine sediment; Mediterranean Water; Pleistocene; statistical analysis; subtropical region; terrigenous deposit; trend analysis; Arabian seas; Climate variabilities; Dust fluxes; East africa; Eastern mediterraneans; Environmental significances; Marine sediments; West-Africa; Dust https://www.scopus.com/inward/record.uri?eid=2-s2.0-59649108494&doi=10.1016%2fj.quascirev.2008.11.003&partnerID=40&md5=9e8381a7a70aa55f90fae17fb4808b4d Cited by: 255 Martin H. Trauth Juan C. Larrasoaña Manfred Mudelsee article Janssen200911 We analyzed the paleostress field, ongoing deformation, meso- to micro-scale faulting, cataclasis, fault rock alteration and veining within turbidite and limestone sequences at the Ganos Fault which represent a major branch of the North Anatolian Fault Zone in NW Turkey. Fault damage was found to occur across a several kilometers wide zone. Effects of faulting are shown by localized subsidiary brittle faults and fault rock alteration in the turbidites as well as fault breccia formation in the limestone sequence. Microseismicity along the Ganos Fault cluster at two locations, the more pronounced being located offshore at a fault bend associated with a change from a transpressional to a transtensional regime. Kinematic analysis reveals a dextral strike-slip regime with components of normal and thrust faulting. Along strike paleostress orientation at the Ganos Fault is rather uniform. Deformation mechanisms and fluid inclusion data from quartz and calcite veins suggest that fault-related quartz veins were formed at temperatures between 170 and 250 °C and pressures between 40 and 120 MPa. Fault-related calcite vein growth occurred during a temperature decrease from 170 °C to 70 °C with pressures likely below 50 MPa. Fluid inclusion and stable isotope data show that the fluids are predominantly of meteoric origin and migrated upwards into the fault. Pure CH4 inclusions in quartz also suggest a biogenic or thermogenic methane origin. © 2008 Elsevier Ltd. All rights reserved. 2009 English 01918141 10.1016/j.jsg.2008.09.010 Journal of Structural Geology 31 11-28 GeoForschungsZentrum, Telegrafenberg, D-14473 Potsdam, Germany; Department of Geological and Environmental Sciences, Ben Gurion University of the Negev, Beer-Sheva, 84105, Israel; Bogazici University, Kandilli Observatory, Earthquake Research Institute, Cengelköy, 81220 Istanbul, Turkey; Istanbul Technical University, Eurasia Institute of Earth Sciences, Faculty of mines, Maslak, 34680 Istanbul, Turkey 1 Fault architecture; Fluid inclusions; Ganos fault; Seismicity; Stable isotopes; Turkey, Calcite; Carbonate minerals; Deformation; Inclusions; Isotopes; Limestone; Methane; Mineralogy; Oxide minerals; Quartz, Structural geology, deformation mechanism; fault zone; faulting; kinematics; North Anatolian Fault; paleostress; strike-slip fault; tectonic evolution, Eurasia; Turkey https://www.scopus.com/inward/record.uri?eid=2-s2.0-57849118402&doi=10.1016%2fj.jsg.2008.09.010&partnerID=40&md5=bfc208ddebdf6105fcc138a9851411d8 cited By 23 C. Janssen M. Bohnhoff Y. Vapnik E. Görgün F. Bulut B. Plessen D. Pohl M. Aktar A.I. Okay G. Dresen article Xuexiang2009267 In order to contribute to a better understanding of exhumation related retrogression processes ultrahigh-pressure (UHP) mafic and ultramafic rocks from the Chinese Continental Scientific Drilling (CCSD) in the Maobei eclogite body of the Sulu ultrahigh-pressure metamorphic belt in eastern China were studied for their magnetofabrics. Variably retrogressed eclogites and serpentinized ultramafic rocks were retrieved from the depth interval of 100 to 1000 m of the borehole. A vein network of irregular shaped veins with a retrograde metamorphic assemblage cuts across the eclogite foliation at both low and high angles. SEM imaging of the eclogites documents that magnetite associated with retrograde pargasitic amphiboles developed around shape-preferred garnet. SEM imaging of the serpentinized ultramafic rocks documents that magnetite rims grew around shape-preferred garnet and that magnetite formed within a mesh texture related to serpentinization. Syn-serpentinization magnetite growth increased bulk susceptibilities, but reduced anisotropy. Maximum susceptibility axes from both eclogites and serpentinized garnet-peridotites trend N-S, i.e. parallel with the stretching lineation as defined by olivine and omphacite grains. This implies that the magnetic fabric mimics the UHP fabric and survived retrogression and that the fabric is inherited from the UHP stage. As a consequence, retrogression was not associated with substantial ductile deformation and the mafic-ultramafic Maobei body behaved as a rigid body within a ductile deforming quartzo-feldspathic matrix during exhumation. Internal strain is restricted to brittle fracturing, associated fluid circulation and vein formation facilitating retrograde reactions in the mafic-ultramafic rocks. © 2008 Elsevier B.V. All rights reserved. Article 2009 English 00401951 10.1016/j.tecto.2008.09.015 Tectonophysics 475 267 – 278 2 Asia; China; Eurasia; Far East; Sulu Belt; Deformation; Drilling; Fabrics; Garnets; Magnetite; Olivine; Oxide minerals; Rocks; Silicate minerals; Textures; CCSD; Exhumation; Magnetofabrics; Sulu; Ultrahigh-pressure; amphibole; Chinese Continental Scientific Drilling Project; eclogite; exhumation; magnetic fabric; magnetite; retrograde metamorphism; texture; ultrahigh pressure metamorphism; ultramafic rock; Metamorphic rocks https://www.scopus.com/inward/record.uri?eid=2-s2.0-70349093161&doi=10.1016%2fj.tecto.2008.09.015&partnerID=40&md5=2f40631aba456adfa109c26bcd09538e Cited by: 7 Qi Xuexiang Jens C. Grimmer Xu Zhiqin article Cohen200960 Article 2009 English 18168957 10.5194/sd-8-60-2009 Scientific Drilling Integrated Ocean Drilling Program 60 – 65 8 https://www.scopus.com/inward/record.uri?eid=2-s2.0-77956536681&doi=10.5194%2fsd-8-60-2009&partnerID=40&md5=498ab389ad5cd677d11ccb320a19e267 Cited by: 22; All Open Access, Gold Open Access, Green Open Access Andrew Cohen Ramon Arrowsmith Anna K. Behrensmeyer Christopher Campisano Craig Feibel Shimeles Fisseha Roy Johnson Zelalem Kubsa Bedaso Charles Lockwood Emma Mbua Daniel Olago Richard Potts Kaye Reed Robin Renaut Jean-Jacques Tiercelin Mohammed Umer article Liu20091225 Zircon from allanite-bearing para- and ortho-gneisses provides a unique insight into the geologic evolution of the Sulu ultrahigh-pressure (UHP) terrane in eastern China. Laser Raman, cathodoluminescence (CL) imaging combined with trace-element, U-Pb, and Lu-Hf isotope data indicate that zircon grains consist of three distinct zones. Inherited magmatic core records a Neoproterozoic protolith age, the coesite-bearing mantle reveals a UHP metamorphic age of 230 ± 7 Ma, and the low-P mineralbearing rim retains an age of 210 ± 3 Ma for the amphibolite-facies retrogression. Positive εHf(t) values for the inherited cores reflect involvement of juvenile materials in the protolith. Low 176Lu/177Hf ratios of coesite-bearing mantles indicate their formation during / after gamet crystallization. Their 176Hf/177Hf ratios are homogenous and more radiogenic than those of the inherited cores, implying fractionation of the Lu-Hf system during isotope equilibration within the metamorphic mineral assemblage. Moreover, coesitebearing mantles show geochemical characteristics that are distinctly different from those of previous studies: (1) The chondritenormalized pattern shows a steep slope from HREE (heavy rare earth elements) to LREE (light rare earth elements) with a moderately negative Eu anomaly (mean Eu/Eu* = 0.53). Such a pattern requires that phases enriched in LREE (e.g., allanite) and europium (e.g., K-feldspar) were stable during UHP conditions. (2) The positive Ce anomaly is very pronounced (Ce/Ce* of 612-657), e.g., about seven to eight times higher than that of the inherited core; (3) The uranium content is very low (6-25 ppm) and the Th/U ratio elevated (0.52-2.83). These data for the coesite-bearing mantle are distinctly different from those of previous studies. We interpret the data to suggest high O fugacity during the UHP and retrograde metamorphic evolution, which also played a critical role in restraining diamond growth in Sulu-Dabie UHP rocks. © 2009 E. Schweizerbart'sehe Verlagsbuchhandlung. Article 2009 English 09351221 10.1127/0935-1221/2009/0021-1965 European Journal of Mineralogy 21 Gebruder Borntraeger Verlagsbuchhandlung 1225 – 1250 6 China; Dabie-Sulu Belt; Sulu Belt; Binary alloys; Exploratory geochemistry; Feldspar; Geochronology; Isotopes; Lead alloys; Levees; Metamorphic rocks; Rare earth elements; Rare earths; Silica; Trace elements; Zircon; Allanite; Coesite; Gneiss; Hf isotope; Sulu UHP terrane; U-Pb dating; allanite; cathodoluminescence; coesite; diamond; gneiss; hafnium; isotopic fractionation; lutetium; rare earth element; retrograde metamorphism; trace element; uranium-lead dating; zircon; Lutetium alloys https://www.scopus.com/inward/record.uri?eid=2-s2.0-77149170566&doi=10.1127%2f0935-1221%2f2009%2f0021-1965&partnerID=40&md5=71aa7a7953c7875bca409171e7cdced3 Cited by: 27 Fulai Liu Axel Gerdes Jahnguang Liou Plnghua Liu article Wang2009340 Our Earth is a dynamic planet, changing on temporal scales ranging from millions of years required to complete a solid Earth cycle, or to form mountain ranges, to the few seconds required for a devastating earthquake or explosive volcanic eruptions. The Cretaceous was a period of great unrest in geologic history. It included a series of extraordinary global geological events - a significant increase of marine water temperature and the deposition of black shales; oceanic anoxia events (OAEs); biotic turnovers and mass extinctions; and the formation of many mountain ranges (California's Sierra Nevada and the Rockies in the western United States, the Andes in South America, and the Alps). Sea level rose during the mid-Cretaceous, covering about a third of the land area. Sea level was up to 250 m higher than at present. © 2009 Society of Exploration Geophysicists. 2009 English 1070485X 10.1190/1.3104081 The Leading Edge 28 Society of Exploration Geophysicists 340-344 China University of Geoscience, Beijing, China; University of California, Santa Cruz, CA, United States 3 Earth (planet); Volcanoes, Geologic history; Geological events; Mass extinction; Mountain ranges; Northeast China; Scientific drilling; Volcanic eruptions; Western United States, Sea level, anoxic conditions; Cretaceous; drilling; mass extinction; mountain region; sea level; seawater; volcanic eruption; water temperature, Alps; Andes; California; China; Rocky Mountains; Sierra Nevada [California]; Songliao Basin; South America; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-63349089165&doi=10.1190%2f1.3104081&partnerID=40&md5=442e79a6f9d1f5ca6f1e466d9380c469 cited By 12 C. Wang Y. Huang X. Zhao article ri2009uppermost 2009 Earth Science Frontiers 16 85 6 CHENG Ri-Hui WANG Guo-Dong WANG Pu-Jun GAO Wei-Feng article wei2009well 2009 Earth Science Frontiers 16 104 6 GAO Wei-Feng WANG Cheng-Shan WANG Pu-Jun MO Xiao-Qiao LIN Yan-An CHENG Ri-Hui WANG Guo-Dong book Pirajno20091 Hydrothermal processes on Earth have played an important role in the evolution of our planet. These processes link the lithosphere, hydrosphere and biosphere in continuously evolving dynamic systems. Terrestrial hydrothermal processes have been active since water condensed to form the hydrosphere, most probably from about 4.4 Ga. The circulation of hot aqueous solution (hydrothermal systems) at, and below, the Earth's surface is ultimately driven by magmatic heat. This book presents an in-depth review of hydrothermal proceses and systems that form beneath the oceans and in intracontinental rifts, continental margins and magmatic arcs. The interaction of hydrothermal fluids with rockwalls, the hydrophere and the biophere, together with changes in their composition through time and space, contribute to the formation of a wide range of mineral deposit types and associated wallrock alteration. On Earth, sites of hydrothermal activity support varied ecosystems based on a range of chemotrophic microorganisms both at surface and in the subsurface. This book also provides an overview of hydrothermal systems associated with meteorite impacts and explores the possibility that hydrothermal processes operate on other terrestrial planets, such as Mars, or satellites of the outer planets such as Titan and Europa. Possible analogues of extraterrestrial putative hydrothermal processes pose the intriguing question of whether primitive life, as we know it, may exist or existed in these planetary bodies. © Springer Science+Business Media B.V. 2009, 2010. 2009 10.1007/978-1-4020-8613-7 Hydrothermal Processes and Mineral Systems 1-1250 Geological Survey of Western Australia, 100 Plain St., East Perth, WA 6004, Australia https://www.scopus.com/inward/record.uri?eid=2-s2.0-84890254144&doi=10.1007%2f978-1-4020-8613-7&partnerID=40&md5=6b42fc3ee6d5840860e548573d5ad734 cited By 775 F. Pirajno article Hrubcová2009275 The structure of the crust and the crust-mantle boundary in the Vogtland/ West Bohemian region have been a target of several seismic measurements for the last 25 years, beginning with the steep-angle reflection seismic studies (DEKORP-4/KTB, MVE-90, 9HR), the refraction and wide-angle experiments (GRANU'95, CELEBRATION 2000, SUDETES 2003), and followed by passive seismic studies (receiver functions, teleseismic tomography). The steep-angle reflection studies imaged a highly reflective lower crust (4 to 6 km thick) with the Moho interpreted in a depth between 30 and 32 km and a thinner crust beneath the Eger Rift. The refraction and wide-angle reflection seismic studies (CELEBRATION 2000) revealed strong wide-angle reflections in a depth of 26-28 km interpreted as the top of the lower crust. Long coda of these reflections indicates strong reflectivity in the lower crustal layer, a phenomenon frequently observed in the Caledonian and Variscan areas. The receiver function studies detected one strong conversion from the base of the crust interpreted as the Moho discontinuity at a depth between 27 and 37 km (average at about 31 km). The discrepancies in the Moho depth determination could be partly attributed to different background of the methods and their resolution, but could not fully explain them. So that new receivers function modelling was provided. It revealed that, instead of a first-order Moho discontinuity, the observations can be explained with a lower crustal layer or a crust-mantle transition zone with a maximum thickness of 5 km. The consequent synthetic ray-tracing modelling resulted in the model with the top of the lower crust at 28 km, where highly reflective lower crustal layer can obscure the Moho reflection at a depth of 32-33 km. © Institute of Geophysics of the ASCR, v.v.i 2009. Article 2009 English 00393169 10.1007/s11200-009-0018-6 Studia Geophysica et Geodaetica 53 275 – 294 3 Bohemian Massif; Central Europe; Eurasia; Europe; Germany; Vogtland; coda; crust-mantle boundary; crustal structure; lower crust; Moho; ray tracing; seismic method; seismic reflection; seismic refraction; transition zone https://www.scopus.com/inward/record.uri?eid=2-s2.0-68349127015&doi=10.1007%2fs11200-009-0018-6&partnerID=40&md5=91031464b34bb6b2ef91f70fc1b1f11b Cited by: 31 Pavla Hrubcová Wolfram H. Geissler article Durand2009115 During 2005-2006, the International Continental Scientific Drilling Program and the U.S. Geological Survey drilled three continuous core holes into the Chesapeake Bay impact structure to a total depth of 1766.3 m. A collection of supplemental materials that presents a record of the core recovery and measurement data for the Eyreville cores is available on CD-ROM at the end of this volume and in the GSA Data Repository. The supplemental materials on the CD-ROM include digital photographs of each core box from the three core holes, tables of the three coring-run logs, as recorded on site, and a set of depth-conversion programs. In this chapter, the contents, purposes, and basic applications of the supplemental materials are briefly described. With this information, users can quickly decide if the materials will apply to their specific research needs. © 2009 The Geological Society of America. 2009 English 00721077 10.1130/2009.2458(05) Special Paper of the Geological Society of America 458 Geological Society of America 115-118 U.S. Geological Survey, 926A National Center, 12201 Sunrise Valley Drive, Reston, VA 20192, United States Boreholes; CD-ROM; Infill drilling; Photography, Basic application; Chesapeake bay impact structures; Continental scientific drillings; Conversion programs; Data repositories; Digital photographs; Measurement data; U.s. geological surveys, Electronic document exchange, borehole logging; impact structure; information technology; photograph, Chesapeake Bay; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-74949124364&doi=10.1130%2f2009.2458%2805%29&partnerID=40&md5=bcce477d7ea7509c9a4a4434260da8f1 cited By 8 C.T. Durand L.E. Edwards M.L. Malinconico D.S. Powars article Larsen2009699 In this study, we extend the knowledge of postimpact alteration processes through an investigation of mineralogy and petrology of 24 samples from the Exmore Formation and sedimentary megablock intervals in the Eyreville borehole within the Chesapeake Bay impact structure and comparisons to similar studies of cored intervals of the Cape Charles borehole. The bulk mineralogical studies reveal quartz, feldspars (microcline and albite), muscovite, smectite-vermiculite clays, and kaolinite with variable quantities of pyrite, zeolites, calcite, and chlorite. X-ray diffraction analysis of the clay (<2 μm) fraction of samples indicates that the clays are dominated by expandable clays with lesser quantities of illite, kaolinite, glauconite, and mixed- layered clays. The expandable clays include smectite, vermiculite, and smectite-vermiculite intergrade varieties; illite interlayering is minimal (generally, <10% illite layers). Thin section and scanning electron microscope petrography in the Exmore breccia show evidence for extensive authigenic expandable clay in the matrix and dispersed pyrite lepispheres and fine calcite rhombs. Grain alteration includes feldspar dissolution and albitization, glauconite recrystallization, and dissolution and expandable-clay replacement of micas. Taken together, the results indicate that low-temperature alteration (maximum temperatures 60-80 °C) is prevalent in the sedimentary clast-rich intervals in the Eyreville cores, and the maximum effects are observed between 600 and 970 m depth. In comparison, the Exmore Formation from the Cape Charles borehole, 8 km to the southwest and overlying the central peak of the inner crater, shows more advanced authigenesis with Fe-rich chlorite, common quartz overgrowths, and mixed-layered illite-smectite clay with as much as 20% interlayered illite. A low-temperature hydrothermal mineral assemblage is documented in suevite and crystalline-clast breccia at depths of 725-820 m in the Cape Charles borehole. The fine-grained clastic target material and contained seawater are argued to have limited initial target melting and initial crater-floor temperatures in the Chesapeake Bay impact structure to an even greater degree than that of other marine craters targeted in consolidated sedimentary substrates. Subsequent hydrothermal circulation was confined to the central uplift and neighboring fractured zones, whereas alteration in the overlying sedimentary breccias involved conductive heat flow, reaction with hypersaline pore fluids, and minor fluid flow into more porous, permeable sedimentary blocks adjacent to the central uplift. © 2009 The Geological Society of America. 2009 10.1130/2009.2458(30) Special Paper of the Geological Society of America 458 699-721 Department of Earth Sciences, University of Memphis, Memphis, TN 38152, United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-74949114717&doi=10.1130%2f2009.2458%2830%29&partnerID=40&md5=84830b590c51f1bd871febf0271f576c cited By 7 D. Larsen E.C. Stephens V.B. Zivkovic article Gohn2009587 An unusually thick section of sedimentary breccias dominated by target-sediment clasts is a distinctive feature of the late Eocene Chesapeake Bay impact structure. A cored 1766-m-deep section recovered from the central part of this marine-target structure by the International Continental Scientific Drilling Program (ICDP)-U.S. Geological Survey (USGS) drilling project contains 678 m of these breccias and associated sediments and an intervening 275-m-thick granite slab. Two sedimentary breccia units consist almost entirely of Cretaceous nonmarine sediments derived from the lower part of the target sediment layer. These sediments are present as coherent clasts and as autoclastic matrix between the clasts. Primary (Cretaceous) sedimentary structures are well preserved in some clasts, and liquefaction and fluidization structures produced at the site of deposition occur in the clasts and matrix. These sedimentary breccias are interpreted as one or more rock avalanches from the upper part of the transient-cavity wall. The little-deformed, unshocked granite slab probably was transported as part of an extremely large slide or avalanche. Water-saturated Cretaceous quartz sand below the slab was transported into the seafloor crater prior to, or concurrently with, the granite slab. Two sedimentary breccia units consist of polymict diamictons that contain cobbles, boulders, and blocks of Cretaceous nonmarine target sediments and less common shocked-rock and melt ejecta in an unsorted, unstratified, muddy, fossiliferous, glauconitic quartz matrix. Much of the matrix material was derived from Upper Cretaceous and Paleogene marine target sediments. These units are interpreted as the deposits of debris flows initiated by the resurge of ocean water into the seafloor crater. Interlayering of avalanche and debris-flow units indicates a partial temporal overlap of the earlier avalanche and later resurge processes. A thin unit of stratified turbidite deposits and overlying laminated fine-grained deposits at the top of the section represents the transition to normal shelf sedimentation. © 2009 The Geological Society of America. 2009 English 00721077 10.1130/2009.2458(26) Special Paper of the Geological Society of America 458 Geological Society of America 587-615 U.S. Geological Survey, 926A National Center, Reston, VA 20192, United States; University of Oslo, P.O. Box 1047, Blindern, N-0316 Oslo, Norway Debris; Deposits; Fluidization; Granite; Infill drilling; Quartz; Sedimentology; Sediments, Chesapeake bay impact structures; Continental scientific drillings; Fluidization structures; Sedimentary structure; Shelf sedimentation; Transient cavities; Turbidite deposits; U.s. geological surveys, Sedimentary rocks, breccia; clast; debris flow; deposition; diamicton; Eocene; fluidization; impact structure; marine sediment; matrix; research program; rock avalanche; sediment transport; sedimentation; turbidite, Chesapeake Bay; United States; Virginia https://www.scopus.com/inward/record.uri?eid=2-s2.0-74949127901&doi=10.1130%2f2009.2458%2826%29&partnerID=40&md5=159b5d2ebbb334eaf6ce5b973386b9ed cited By 28 G.S. Gohn D.S. Powars H. Dypvik L.E. Edwards article Kulpecz2009811 The Eyreville and Exmore, Virginia, core holes were drilled in the inner basin and annular trough, respectively, of the Chesapeake Bay impact structure, and they allow us to evaluate sequence deposition in an impact crater. We provide new high-resolution geochronologic (&lt;1 Ma) and sequence-stratigraphic interpretations of the Exmore core, identify 12 definite (and four possible) postimpact depositional sequences, and present comparisons with similar results from Eyreville and other mid- Atlantic core holes. The concurrence of increases in δ 18 O with Chesapeake Bay impact structure sequence boundaries indicates a primary glacioeustatic control on deposition. However, regional comparisons show the differential preservation of sequences across the mid-Atlantic margin. We explain this distribution by the compaction of impactites, regional sediment-supply changes, and the differential movement of basement structures. Upper Eocene strata are thin or missing updip and around the crater, but they thicken into the inner basin (and offshore to the southeast) due to rapid crater infilling and concurrent impactite compaction. Oligocene sequences are generally thin and highly dissected throughout the mid-Atlantic region due to sediment starvation and tectonism, except in southeastern New Jersey. Regional tectonic uplift of the Norfolk Arch coupled with a southward decrease in sediment supply resulted in: (1) largely absent Lower Miocene sections around the Chesapeake Bay impact structure compared to thick sections in New Jersey and Delaware; (2) thick Middle Miocene sequences across the Delmarva Peninsula that thin south of the Chesapeake Bay impact structure; and (3) upper Middle Miocene sections that pinch out just north of the Chesapeake Bay impact structure. Conversely, the Upper Miocene-Pliocene section is thick across Virginia, but it is poorly represented in New Jersey because of regional variations in relative subsidence. © 2009 The Geological Society of America. 2009 English 00721077 10.1130/2009.2458(34) Special Paper of the Geological Society of America 458 Geological Society of America 811-837 Department of Geological Sciences, Rutgers University, Piscataway, NJ 08854, United States; U.S. Geological Survey, 12201 Sunrise Valley Drive, Reston, VA 20192, United States; Delaware Geological Survey, 257 Academy Street, Newark, DE 19716, United States; Chevron Energy Technology Company, 1500 Louisiana St., Houston, TX 77002, United States Compaction; Concurrency control; Infill drilling; Offshore oil well production; Sediments; Stratigraphy, Basement structures; Chesapeake bay impact structures; Depositional sequences; Regional tectonics; Regional variation; Sediment starvation; Sequence boundary; Sequence-stratigraphic interpretation, Deposition, deposition; depositional sequence; Eocene; geochronology; glacioeustacy; impact structure; Miocene; Oligocene; Pliocene; sedimentation rate; sequence boundary; sequence stratigraphy; subsidence, Chesapeake Bay; Delmarva Peninsula; New Jersey; United States; Virginia https://www.scopus.com/inward/record.uri?eid=2-s2.0-74949108348&doi=10.1130%2f2009.2458%2834%29&partnerID=40&md5=7b1fffd4bd77bb74e1bcc61eb1b4f490 cited By 15 A.A. Kulpecz K.G. Miller J.V. Browning L.E. Edwards D.S. Powars P.P. McLaughlin Jr. A.D. Harris M.D. Feigenson article Malinconico2009905 Vitrinite reflectance data from the International Continental Scientific Drilling Program (ICDP)-U.S. Geological Survey (USGS) Eyreville deep cores in the centralcrater moat of the Chesapeake Bay impact structure and the Cape Charles test holes on the central uplift show patterns of postimpact maximum-temperature distribution that result from a combination of conductive and advective heat flow. Within the crater-fill sediment-clast breccia sequence at Eyreville, an isoreflectance (-0.44% Ro) section (525-1096 m depth) is higher than modeled background coastal-plain maturity and shows a pattern typical of advective fluid flow. Below an intervening granite slab, a short interval of sediment-clast breccia (1371-1397 m) shows a sharp increase in reflectance (0.47%-0.91% Ro) caused by conductive heat from the underlying suevite (1397-1474 m). Refl ectance data in the uppermost suevite range from 1.2% to 2.1% Ro. However, heat conduction alone is not sufficient to affect the temperature of sediments more than 100 m above the suevite. Thermal modeling of the Eyreville suevite as a 390 °C cooling sill-like hot rock layer supplemented by compaction- driven vertical fluid flow (0.046 m/a) of cooling suevitic fluids and deeper basement brines (120 °C) upward through the sediment breccias closely reproduces the measured reflectance data. This scenario would also replace any marine water trapped in the crater fill with more saline brine, similar to that currently in the crater, and it would produce temperatures sufficient to kill microbes in sediment breccias within 450 m above the synimsuevite. A similar downhole maturity pattern is present in the sediment-clast breccia over the central uplift. High-reflectance (5%-9%) black shale and siltstone clasts in the suevite and sediment-clast breccia record a pre-impact (Paleozoic?) metamorphic event. Previously published maturity data in the annular trough indicate no thermal effect there from impact-related processes. © 2009 The Geological Society of America. 2009 English 00721077 10.1130/2009.2458(38) Special Paper of the Geological Society of America 458 Geological Society of America 905-930 U.S. Geological Survey, 926A National Center, Reston, VA 20192, United States; U.S. Geological Survey, 431 National Center, Reston, VA 20192, United States; Department of Geology and Environmental Geosciences, Lafayette College, Easton, PA 18042, United States Boreholes; Compaction; Heat conduction; Infill drilling; Reflection; Rocks; Saline water; Sediments; Software testing, Chesapeake bay impact structures; Conductive heat; Continental scientific drillings; Metamorphic events; Reflectance data; U.s. geological surveys; Vertical fluid flow; Vitrinite reflectance, Flow of fluids, black shale; breccia; crater; fluid flow; geological survey; heat flow; impact structure; Ocean Drilling Program; temperature effect; thermal conductivity; thermal regime; uplift; vitrinite reflectance, Chesapeake Bay; United States, Calluna vulgaris https://www.scopus.com/inward/record.uri?eid=2-s2.0-74949126189&doi=10.1130%2f2009.2458%2838%29&partnerID=40&md5=ed452658d198522b310e1a0774420030 cited By 17 M.L. Malinconico W.E. Sanford W.J.J. Wright Horton Jr. article Gibson2009235 Pre-impact crystalline rocks of the lowermost 215 m of the Eyreville B drill core from the Chesapeake Bay impact structure consist of a sequence of pelitic mica schists with subsidiary metagraywackes or felsic metavolcanic rocks, amphibolite, and calc-silicate rock that is intruded by muscovite (±biotite, garnet) granite and granite pegmatite. The schists are commonly graphitic and pyritic and locally contain plagioclase porphyroblasts, fi brolitic sillimanite, and garnet that indicate middle- to upper-amphibolite-facies peak metamorphic conditions estimated at ̃0.4-0.5 GPa and 600-670 °C. The schists display an intense, shallowly dipping, S1 composite shear foliation with local micrometer- to decimeter-scale recumbent folds and S-C' shear band structures that formed at high temperatures. Zones of chaotically oriented foliation, resembling breccias but showing no signs of retrogression, are developed locally and are interpreted as shear-disrupted fold hinges. Mineral textural relations in the mica schists indicate that the metamorphic peak was attained during D1. Fabric analysis indicates, however, that subhorizontal shear deformation continued during retrograde cooling, forming mylonite zones in which high-temperature shear fabrics (S-C and S-C') are overprinted by progressively lower- temperature fabrics. Cataclasites and carbonate-cemented breccias in more competent lithologies such as the calc-silicate unit and in the felsic gneiss found as boulders in the overlying impactite succession may refl ect a fi nal pulse of low-temperature cataclastic deformation during D1. These breccias and the shear and mylonitic foliations are cut by smaller, steeply inclined anastomosing fractures with chlorite and calcite infill (interpreted as D2). This D2 event was accompanied by extensive chlorite-sericitecalcite ± epidote retrogression and appears to predate the impact event. Granite and granite pegmatite veins display local discordance to the S1 foliation, but elsewhere they are affected by high-temperature mylonitic shear deformation, suggesting a late-D1 intrusive timing close to the metamorphic peak. The D1 event is tentatively interpreted as a thrusting event associated with westward-verging collision between Gondwana and Laurentia before or during the Permian-Carboniferous Alleghanian orogeny. It is unclear whether subsequent brittle deformation, described here as D2, could be part of regional dextral Alleghanian strike-slip faulting or younger Mesozoic normal faulting. © 2009 The Geological Society of America. 2009 English 00721077 10.1130/2009.2458(12) Special Paper of the Geological Society of America 458 Geological Society of America 235-254 Impact Cratering Research Group, School of Geosciences, University of the Witwatersrand, P.O. WITS, Johannesburg 2050, South Africa; U.S. Geological Survey, 926A National Center, Reston, VA 20192, United States; Museum für Naturkunde-eibniz Institute, Humboldt University Berlin, Invalidenstrasse 43, 10115 Berlin, Germany Calcite; Core drilling; Crystalline materials; Fault slips; Feldspar; Garnets; Granite; Infill drilling; Mica; Shear deformation; Silicate minerals; Strike-slip faults; Structural geology; Temperature, Amphibolite facies; Brittle deformation; Cataclastic deformation; Chesapeake bay impact structures; Crystalline basement; Metamorphic conditions; Metavolcanic rocks; Strike slip faulting, Crystalline rocks, amphibolite; brittle deformation; crystalline rock; faulting; impact structure; metagreywacke; metamorphism; metavolcanic rock; schist; tectonic evolution; thermal evolution, Chesapeake Bay; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-74949139873&doi=10.1130%2f2009.2458%2812%29&partnerID=40&md5=a4b46a449cd73b6b00e9a9f1a32862f9 cited By 14 R.L. Gibson G.N. Townsend J.W. Horton Jr. W.U. Reimold article Prokopenko2009111 Repetitive patterns in the records of total organic carbon (TOC), total nitrogen (TN) and δ13Corg observed in the Lake Hovsgol sediment section from HDP-04 drill core reflect past changes in productivity of Lake Hovsgol and in the isotopic composition of the lake's carbon pool. Lake Hovsgol productivity proxy signals are interpreted to represent the response of the Hovsgol lacustrine system to glacial-interglacial cycles of the Pleistocene. This interpretation is supported by the apparent orbitally-forced pattern in the TOC, TN and δ13Corg records of the past 250 ka in the BDP-96-2 drill core from neighboring Lake Baikal. The intervals with independent age control, such as the radiocarbon-dated last glacial-interglacial transition and the paleomagnetic reversals, make it evident that productivity proxy signals are reliable indicators of past cold-to-warm and warm-to-cold climate transitions, as seen from the agreement with the pattern of global climate change in marine δ18O records. The Brunhes/Matuyama reversal during the MIS 19 interglacial coincides with a distinct peak of TOC and TN in the Hovsgol record, similar to the signal during the Holocene interglacial. By contrast, the upper Jaramillo reversal in the Lake Hovsgol record occurs in a diatom-free calcareous interval characterized by minima in TOC, TN and by a 'glacial'-type range of δ13Corg values. In both Lake Baikal and Lake Hovsgol records, peaks in TOC and TN contents help distinguishing past interglacials and interstadials, and isotopically-heaviest δ13Corg values help identify past glacial intervals. An age model for the HDP-04 drill core section is proposed based on recognizing the repetitive patterns in Lake Hovsgol productivity and lithologic records as regional paleoclimate cycles of middle to late Pleistocene. Absolute dates and diatom biostratigraphic correlation ties to the Lake Baikal record are used as key controls. In the proposed age model, the interval 81-24 m in the HDP-04 sediment section below the major unconformity is correlated to MIS 27 through late MIS 13, whereas the upper 24 m of the HDP-04 section is suggested to have recovered the sedimentary record of late MIS 7 to MIS 1. Article 2009 English 10406182 10.1016/j.quaint.2009.02.030 Quaternary International 205 111 – 125 1-2 Asia; Eurasia; Far East; Hvsgol Aymag; Lake Baikal; Mongolia; Russian Federation; Bacillariophyta; biostratigraphy; climate change; diatom; Holocene; interglacial; isotopic composition; lacustrine deposit; nitrogen; paleoclimate; paleoenvironment; Pleistocene; sediment core; total organic carbon https://www.scopus.com/inward/record.uri?eid=2-s2.0-68049148361&doi=10.1016%2fj.quaint.2009.02.030&partnerID=40&md5=856916b903f81245f4faf5ccea77eb78 Cited by: 13 A.A. Prokopenko G.K. Khursevich M.I. Kuzmin T. Kawai article He2009525 The Chinese Continental Scientific Drilling (CCSD) project is located at the Sulu ultrahigh-pressure metamorphic (UHPM) belt. It offers a unique opportunity for studying the radiogenic heat production of both shallower and deeper rocks. Based on the concentrations of radiogenic elements U, Th and K on 349 samples from main hole of CCSD (CCSD MH), pilot holes and exposures, we determined radiogenic heat productions of all major rock types in the Sulu UHPM belt. Results show the mean values of orthogneiss and paragneiss are respectively 1.65 ± 0.81 and 1.24 ± 0.61 μW m- 3. Due to different composition and grade of retrogressive metamorphism, the eclogites display significant scatter in radiogenic heat production, ranging from 0.01 to 2.85 μW m- 3, with a mean of 0.44 ± 0.55 μW m- 3. The radiogenic heat production in ultramafic rocks also varies within a large range of 0.02 to 1.76 μW m- 3, and the average turns out to be 0.18 ± 0.31 μW m- 3. Based on the measurements and crustal petrologic model, the vertical distribution model of heat production in Sulu crust is established. The resulting mean heat production (0.76 μW m- 3) contributes 24 mW m- 2 to the surface heat flow. 1-D thermal model indicates that the temperature at the Moho reaches above 750 °C, and the thermal thickness of the lithosphere is ~ 75 km, in good agreement with the geophysical results. The high teat flow (~ 75 mW m- 2) together with thin lithosphere presents strong support for the extension events during the late Cretaceous and Cenozoic. © 2008 Elsevier B.V. All rights reserved. Article 2009 English 0012821X 10.1016/j.epsl.2008.11.022 Earth and Planetary Science Letters 277 525 – 538 3-4 Asia; China; Eurasia; Far East; Sulu Belt; Calluna vulgaris; Structural geology; Uranium alloys; CCSD; CCSD-MH; Cenozoic; Chinese Continental Scientific drillings; Eclogites; Heat productions; Large ranges; Mean values; Metamorphic belts; Pilot holes; radiogenic heat production; Rock types; Sulu UHPM belt; Surface heat flows; Thermal models; thermal structure; Ultramafic rocks; Vertical distributions; Cenozoic; Chinese Continental Scientific Drilling Project; Cretaceous; eclogite; heat flow; heat production; lithosphere; metamorphism; Moho; petrology; retrogression; thermal structure; ultrahigh pressure metamorphism; ultramafic rock; vertical distribution; Production https://www.scopus.com/inward/record.uri?eid=2-s2.0-58149277130&doi=10.1016%2fj.epsl.2008.11.022&partnerID=40&md5=515a205daf763c1e136fb5a8563bb863 Cited by: 34 Lijuan He Shengbiao Hu Wencai Yang Jiyang Wang article pienitz2009results 2009 Pages News 17 117-118 3 R Pienitz M Melles B Zolitschka article Cordonnier2009263 Transitions between effusive and explosive styles of lava dome eruptions are likely accompanied by changes in lava rheology. The common presence of crystals in dome lavas produces a complex non-Newtonian rheology. Thus models of such complex rheology are essential for volcanic eruption models. Here, we have measured the rheology of natural Unzen lavas with a compressive uniaxial press operating at stresses between 1 and 70 MPa and temperatures between 940 and 1010 °C. Crystal-rich Unzen lavas are characterised by two essential rheological features which produce non-Newtonian effects. The first is an instantaneous response of the apparent viscosity to applied stress which requires that the magma be described as a visco-elastic fluid that exhibits shear-thinning. The second effect takes the form of a time-dependence of the viscosity at moderate to high stress (≥ 10 MPa). In this regime, the apparent viscosity slowly decreases as increasing fracturing of the phenocrysts and the groundmass occurs. Fragmentation of crystals and alignment of crystal fragments are observed to produce flow banding-effects which in turn lower the apparent viscosity of natural dome lavas. Ultimately, deformation may lead to complete rupture of the lava if the stress is sufficient. Cracking thus stands as an important process in natural dome lava rheology. The ubiquitous non-Newtonian rheology of dome lavas, observed experimentally here, needs to be adequately treated in order to generate appropriate eruption models. © 2008 Elsevier B.V. All rights reserved. 2009 English 0012821X 10.1016/j.epsl.2009.01.014 Earth and Planetary Science Letters 279 263-272 Ludwig-Maximilians Universität, Theresienstrasse 41 /III, D-80333 Munich, Germany 3-4 brittle; ductile; flow banding; lava; magma; non-Newtonian rheology; Unzen; visco-elastic, Cements; Crystals; Domes; Elasticity; Non Newtonian flow; Plasticity; Rheology; Volcanic rocks; Volcanoes, Viscosity, cracking; crystal structure; deformation; fragmentation; lava dome; magma; phenocryst; rheology; stress; viscoelasticity; volcanic eruption; volcanic rock, Asia; Eurasia; Far East; Japan; Kyushu; Nagasaki [Kyushu]; Unzen Volcano https://www.scopus.com/inward/record.uri?eid=2-s2.0-60949113083&doi=10.1016%2fj.epsl.2009.01.014&partnerID=40&md5=ade738563fb955a325c3a7494e85ff54 cited By 91 B. Cordonnier K.-U. Hess Y. Lavallée D.B. Dingwell article Elbra2009119 Chesapeake is a 35-Ma-old shallow-marine, complex impact structure with a diameter of ̃85 km. The structure is completely buried beneath several hundreds of meters of postimpact sediments. Therefore, subsurface information can be obtained only from geophysical surveys and drill holes. Recently, deep drilling into the inner crater zone, at Eyreville near Cape Charles, was carried out in order to provide constraints on geophysical modeling and cratering processes in a multilayered marine target. We analyzed samples of the Eyreville core including postimpact, impactproduced, and basement-derived units in order to clarify the magneto-mineralogy, to provide physical parameters for better understanding the influence of the impact on the petrophysical and rock-magnetic properties, and to provide rock-magnetic data for magnetic modeling. Results show a complex behavior of physical properties of the lithologies in the Eyreville core due to different lithologies having been affected by shock-induced changes. Our data suggest that pyrrhotite and magnetite carry the magnetic properties in most of the core samples, whereas hematite is present in oxidized clays from the uppermost impact-generated unit (Exmore beds) and related sediment megablocks. The granitic megablock appears to be undeformed based on lack of brittle deformation in magnetite and petrophysically appears as a single block. In contrast, the impactite sequence below the megablock shows brittle deformation and magnetic fabric randomization, and the pyrrhotite in the associated schist fragments is strongly fractured. Thus, the Chesapeake Bay deep core provides an extraordinary opportunity to study the effect of impact on magnetite and pyrrhotite, the two main magnetic minerals creating crustal magnetic anomalies. © 2009 The Geological Society of America. 2009 English 00721077 10.1130/2009.2458(06) Special Paper of the Geological Society of America 458 Geological Society of America 119-135 Laboratory of Solid Earth Geophysics, Department of Physics, 00014 University of Helsinki, P.O. Box 64, Finland; Institute of Applied Geosciences, Karlsruhe University, Hertzstrasse 16, 76187 Karlsruhe, Germany Core samples; Deformation; Geomagnetism; Hematite; Infill drilling; Iron ores; Lithology; Magnetic properties; Magnetite; Petrophysics; Structural geology, Brittle deformation; Chesapeake bay impact structures; Crustal magnetic anomalies; Geophysical modeling; Geophysical surveys; Physical parameters; Rock magnetic properties; Subsurface information, Structural properties, brittle deformation; cratering; geophysical survey; hematite; impact structure; magnetic anomaly; magnetic method; magnetic mineral; magnetic property; magnetite; mineralogy; physical property; pyrrhotite, Chesapeake Bay; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-74949111562&doi=10.1130%2f2009.2458%2806%29&partnerID=40&md5=99a236211722fc3123ed6f7b9db4dce5 cited By 15 T. Elbra A. Kontny L.J. Pesonen article Hung2009307 Continuous cores and a suit of geophysical measurements were collected in two scientific drill holes to understand physical mechanisms involved in the large displacements during the 1999 Chi-Chi earthquake. Physical properties obtained from wire-line logs including P- and S-wave sonic velocity, gamma ray, electrical resistivity, density and temperature, are primarily dependent on parameters such as lithology, depth and fault zones. The average dip of bedding, identified from both cores and FMI (or FMS) logs, is about 30° towards SE. Nevertheless, local azimuthal variations and increasing or decreasing bedding dips appear across fault zones. A prominent increase of structural dip to 60°-80° below 1856 m could be due to deformation associated with propagation of the Sanyi fault. A total of 12 fault zones identified in hole-A are located in the Plio-Pleistocene Cholan Formation, Pliocene Chinshui Shale and Miocene Kueichulin Formation. The shallowest fault zone occurs at 1111 m depth (FZ1111). It is a 1 m gouge zone including 12 cm of thick indurate black material. We interpreted this zone as the slip zone during Chi-Chi earthquake. FZ1111 is characterized by: 1) bedding-parallel thrust fault with 30-degree dip; 2) the lowest resistivity; 3) low density, Vp and Vs, 4) high Vp/Vs ratio and Poisson's ratio; 5) low energy and velocity anisotropy, and low permeability within the homogeneous 1 m gouge zone; 6) increasing gas (CO2 and CH4) emissions, and 7) appearance of smectite within the primary slip zone. In situ stresses at the drill site were inferred from leak-off tests, borehole breakouts and drilling-induced tensile fractures from borehole FMS/FMI logs, and shear seismic wave anisotropy from DSI logs. The dominant fast shear-wave polarization direction is in good agreement with regional maximum horizontal stress axis, particularly within the strongly anisotropic Kueichulin Formation. A conjugate set of secondary directions are parallel to microcrack orientations. A drastic change of orientation of fast shear-wave polarization across the Sanyi thrust fault at the depth of 1712 m reflects the change of stratigraphy, physical properties and structural geometry. © 2007 Elsevier B.V. All rights reserved. 2009 English 00401951 10.1016/j.tecto.2007.11.014 Tectonophysics 466 307-321 Institute of Geophysics, National Central University, Jhongli, Taiwan; Center for Deep Earth Exploration, Japan Agency for Marine-Earth Science and Technology, Japan; Kochi Institute for Core Sample Research, Japan Agency for Marine-Earth Science and Technology, Japan 3-4 Azimuthal variations; Black materials; Chi-Chi earthquake; Drill holes; Drill sites; Drilling-induced tensile fractures; Electrical resistivities; Fault zones; Fault-zone properties; Gamma-ray; Geophysical measurements; Horizontal stress; In-situ stress; Large displacements; Leak-off tests; Low densities; Low energies; Low permeabilities; Micro cracks; Miocene; Physical mechanisms; Plio-pleistocene; Pliocene; Poisson's ratios; S-wave anisotropy; Slip zones; Smectite; Sonic velocities; Stress state; Structural geometries; Subsurface structures; Taiwan Chelungpu Fault Drilling Project; Thrust faults; Velocity anisotropies; Wave polarizations, Anisotropy; Clay minerals; Drilling; Earthquakes; Electric resistance; Gamma rays; Lithology; Poisson ratio; Polarization; Rock drills; Seismic waves; Shear waves; Stratigraphy; Structural geology; Thermal logging; Viscosity measurement; Waves, Boreholes, borehole breakout; Chi-Chi earthquake 1999; deformation; drilling; fault geometry; fault propagation; fault zone; in situ stress; lithology; Miocene; P-wave; physical property; Pleistocene; Pliocene; S-wave; seismic anisotropy; wave velocity https://www.scopus.com/inward/record.uri?eid=2-s2.0-60649107827&doi=10.1016%2fj.tecto.2007.11.014&partnerID=40&md5=472cf8a3aba0ba3af43d3351aaff7ff7 cited By 52 J.-H. Hung K.-F. Ma C.-Y. Wang H. Ito W. Lin E.-C. Yeh article Wagner200951 In summary, the SCOPSCO workshop provided a reliable platflorm to discuss the present state of knowledge and future steps towards a deep drilling campaign. A full proposal for an ICDP drilling campaign will be submitted in 2009. Conference paper 2009 English 18163459 10.2204/iodp.sd.7.08.2009 Scientific Drilling 51 – 53 7 Deep drillings; Lake ohrid; Scientific collaborations https://www.scopus.com/inward/record.uri?eid=2-s2.0-78651581215&doi=10.2204%2fiodp.sd.7.08.2009&partnerID=40&md5=e8e6b671015b5ad20b18dd3969ddff82 Cited by: 3; All Open Access, Gold Open Access, Green Open Access Bernd Wagner Thomas Wilke Sebastian Krastel-Gudegast Andon Grazhdani Klaus Reicherter Sasho Trajanovski Giovanni Zanchetta article McDonald2009469 This paper documents an attempt to detect a meteoritic component in both washback (resurge) crater-fill breccia (the so-called Exmore breccia) and in suevites from the Eyreville core hole, which was drilled several kilometers from the center of the 85-km-diameter Chesapeake Bay impact structure, Virginia, USA. Determining the presence of an extraterrestrial component and, in particular, the projectile type for this structure, which is the largest impact structure currently known in the United States, is of importance because it marks one of several large impact events in the late Eocene, during which time the presence of extraterrestrial 3He and multiple impact ejecta layers provide evidence for a comet or asteroid shower. Previous work has indicated an ordinary chondritic projectile for the largest of the late Eocene craters, the Popigai impact structure in Siberia. The exact relation between the Chesapeake Bay impact event and siderophile element anomalies documented in late Eocene ejecta layers from around the world is not clear. The only clear indication for an extraterrestrial component related to this structure has been the discovery of a meteoritic osmium isotopic signature in impact melt rocks recovered from a hydrogeologic test hole located on Cape Charles near the center of the structure, and confirmation of a similar signature in suevitic rocks would have been desirable in order to place constraints on the type of projectile involved in formation of the Chesapeake Bay crater. Unfortunately, the current data show no discernible differences in the contents of the platinum group elements (PGEs) among the suevite, the Exmore breccia, and several crystalline basement rocks, all from the Eyreville core hole. Abundances of PGEs are uniformly low (e.g., <0.1 ppb Ir), and chondrite-normalized abundance patterns are nonchondritic. These data do not allow unambiguous verification of an extraterrestrial signature. Thus, the nature of the Chesapeake Bay projectile remains ambiguous. © 2009 The Geological Society of America. 2009 English 00721077 10.1130/2009.2458(21) Special Paper of the Geological Society of America 458 Geological Society of America 469-479 School of Earth, Ocean and Planetary Sciences, Cardiff University, Park Place, Cardiff CF10 3YE, United Kingdom; Department of Lithospheric Research, University of Vienna, Althanstrasse 14, Vienna, A-1090, Austria Crystalline rocks; Hydrogeology; Infill drilling; Isotopes; Meteorites; Platinum; Projectiles; Rocks, Chesapeake bay impact structures; Crystalline basement; Extraterrestrial components; Impact structures; Isotopic signatures; Platinum group elements; Platinum group elements (PGEs); Siderophile elements, Economic geology, breccia; chondrite; coastal sediment; ejecta; Eocene; impact structure; isotopic composition; meteorite; osmium; platinum group element; research program; sediment chemistry; siderophile element; suevite, Chesapeake Bay; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-74949113207&doi=10.1130%2f2009.2458%2821%29&partnerID=40&md5=e7dacf6de41d8b08642e5cbda3f4ac73 cited By 10 I. Mcdonald K. Bartosova C. Koeberl article McDonald2009469 This paper documents an attempt to detect a meteoritic component in both washback (resurge) crater-fill breccia (the so-called Exmore breccia) and in suevites from the Eyreville core hole, which was drilled several kilometers from the center of the 85-km-diameter Chesapeake Bay impact structure, Virginia, USA. Determining the presence of an extraterrestrial component and, in particular, the projectile type for this structure, which is the largest impact structure currently known in the United States, is of importance because it marks one of several large impact events in the late Eocene, during which time the presence of extraterrestrial 3He and multiple impact ejecta layers provide evidence for a comet or asteroid shower. Previous work has indicated an ordinary chondritic projectile for the largest of the late Eocene craters, the Popigai impact structure in Siberia. The exact relation between the Chesapeake Bay impact event and siderophile element anomalies documented in late Eocene ejecta layers from around the world is not clear. The only clear indication for an extraterrestrial component related to this structure has been the discovery of a meteoritic osmium isotopic signature in impact melt rocks recovered from a hydrogeologic test hole located on Cape Charles near the center of the structure, and confirmation of a similar signature in suevitic rocks would have been desirable in order to place constraints on the type of projectile involved in formation of the Chesapeake Bay crater. Unfortunately, the current data show no discernible differences in the contents of the platinum group elements (PGEs) among the suevite, the Exmore breccia, and several crystalline basement rocks, all from the Eyreville core hole. Abundances of PGEs are uniformly low (e.g., <0.1 ppb Ir), and chondrite-normalized abundance patterns are nonchondritic. These data do not allow unambiguous verification of an extraterrestrial signature. Thus, the nature of the Chesapeake Bay projectile remains ambiguous. © 2009 The Geological Society of America. 2009 10.1130/2009.2458(21) Special Paper of the Geological Society of America 458 469-479 School of Earth, Ocean and Planetary Sciences, Cardiff University, Park Place, Cardiff CF10 3YE, United Kingdom; Department of Lithospheric Research, University of Vienna, Althanstrasse 14, Vienna, A-1090, Austria https://www.scopus.com/inward/record.uri?eid=2-s2.0-74949113207&doi=10.1130%2f2009.2458%2821%29&partnerID=40&md5=e7dacf6de41d8b08642e5cbda3f4ac73 cited By 10 I. Mcdonald K. Bartosova C. Koeberl article Zhang2009297 The major cation and anion compositions of waters from the Lake Qinghai river system (LQRS) in the northeastern Tibetan Plateau were measured. The waters were collected seasonally from five main rivers during premonsoon (late May), monsoon (late July), and post-monsoon (middle October). The LQRS waters are all very alkaline and have high concentrations of TDS (total dissolved solids) compared to rivers draining the Himalayas and the southeastern Tibetan Plateau. Seasonal variations in the water chemistry show that, except the Daotang River, the TDS concentration is high in October and low in July in the LQRS waters. The forward models were used to quantify the input of three main rivers (Buha River, Shaliu River, and Hargai River) from rain, halite, carbonates, and silicates. The results suggest that (1) atmospheric input is the first important source for the waters of the Buha River and the Shaliu River, contributing 36-57% of the total dissolved cations, (2) carbonate weathering input and atmospheric input have equal contribution to the Hargai River water, (3) carbonate weathering has higher contribution to these rivers than silicate weathering, and (4) halite is also important source for the Buha River. The Daotang River water is dominated by halite input owing to its underlying old lacustrine sediments. The water compositions of the Heima River are controlled by carbonate weathering and rainfall input in monsoon season, and groundwater input may be important in pre-monsoon and post-monsoon seasons. After being corrected the atmospheric input, average CO2 drawdown via silicate weathering in the LQRS is 35×103 mol/km2 per year, with highest in monsoon season, lower than Himalayas and periphery of Tibetan Plateau rivers but higher than some rivers draining shields. © Springer-Verlag 2009. Article 2009 English 18666299 10.1007/s12665-009-0027-3 Environmental Earth Sciences 59 297 – 313 2 China; Himalayas; Qinghai; Qinghai Lake; Qinghai-Xizang Plateau; Atmospheric chemistry; Atmospheric thermodynamics; Carbonation; Dissolution; Geochemistry; Groundwater; Lakes; Positive ions; Rain; Sediments; Silicates; Sodium chloride; Soil mechanics; Water levels; Weathering; Anion composition; Atmospheric inputs; Carbonate weathering; Chemical weathering; Forward models; High concentration; Himalayas; Lacustrine sediments; Monsoon season; Post-monsoon; Pre-monsoon; River systems; River water; Seasonal variation; Silicate weathering; Tibetan Plateau; Total dissolved solids; Water chemistry; Water composition; carbon dioxide; chemical weathering; ionic composition; lacustrine deposit; river system; river water; seasonal variation; water chemistry; Rivers https://www.scopus.com/inward/record.uri?eid=2-s2.0-70349180210&doi=10.1007%2fs12665-009-0027-3&partnerID=40&md5=93596875acdec828dfac96ecc1f49041 Cited by: 25 Fei Zhang Zhangdong Jin Guang Hu Fuchun Li Yuewei Shi article zhong2009sedimentary 2009 Geochimica 38 487-497 YF Zhong JT Guo L Wang ZG Song article Huang2009 In hydrate-bearing sediments, the velocity and attenuation of compressional and shear waves depend primarily on the spatial distribution of hydrates in the pore space of the subsurface lithologies. Recent characterizations of gas hydrate accumulations based on seismic velocity and attenuation generally assume homogeneous sedimentary layers and neglect effects from large- and small-scale heterogeneities of hydrate-bearing sediments. We present an algorithm, based on stochastic medium theory, to construct heterogeneous multivariable models that mimic heterogeneities of hydrate-bearing sediments at the level of detail provided by borehole logging data. Using this algorithm, we model some key petrophysical properties of gas hydrates within heterogeneous sediments near the Mallik well site, Northwest Territories, Canada. The modeled density, and P and S wave velocities used in combination with a modified Biot-Gassmann theory provide a first-order estimate of the in situ volume of gas hydraté near the Mallik 5L-38 borehole. Our results suggest a range of 528 to 768 × 106 m3/km2 of natural gas trapped within hydrates, nearly an order of magnitude lower than earlier estimates which did not include effects of small-scale heterogeneities. Further, the petrophysical models are combined with a 3-D finite difference modeling algorithm to study seismic attenuation due to scattering and leaky mode propagation. Simulations of a near-offset vertical seismic profile and cross-borehole numerical surveys demonstrate that attenuation of seismic energy may not be directly related to the intrinsic attenuation of hydrate-bearing sediments but, instead, may be largely attributed to scattering from small-scale heterogeneities and highly attenuate leaky mode propagation of seismic waves through larger-scale heterogeneities in sediments. Copyright 2009 by the American Geophysical Union. 2009 English 21699313 10.1029/2008JB006172 Journal of Geophysical Research: Solid Earth 114 Blackwell Publishing Ltd Department of Physics, University of Toronto, 60 Saint George Street, Toronto, ON M5S 1A7, Canada; Geological Survey of Canada, 615 Booth Street, Ottawa, ON KlA 0E9, Canada 7 borehole; fault propagation; finite difference method; gas hydrate; geoaccumulation; heterogeneity; natural gas; P-wave; reservoir; S-wave; seismic attenuation; seismic velocity; spatial distribution; stochasticity; three-dimensional modeling, Canada; North America https://www.scopus.com/inward/record.uri?eid=2-s2.0-70349687445&doi=10.1029%2f2008JB006172&partnerID=40&md5=cf122661888647d3a9513fc631a9a0ee cited By 42 J.-W. Huang G. Bellefleur B. Milkereit article Belkin2009447 Optical and electron-beam petrography of melt-rich suevite and melt-rock clasts from selected samples from the Eyreville B core, Chesapeake Bay impact structure, reveal a variety of silicate glasses and coexisting sulfur-rich melts, now quenched to various sulfi de minerals (±iron). The glasses show a wide variety of textures, fl ow banding, compositions, devitrifi cation, and hydration states. Electron-microprobe analyses yield a compositional range of glasses from high SiO 2 (&gt;90 wt%) through a range of lower SiO 2 (55-75 wt%) with no relationship to depth of sample. Some samples show spherical globules of different composition with sharp menisci, suggesting immiscibility at the time of quenching. Isotropic globules of higher interfacial tension glass (64 wt% SiO 2 ) are in sharp contact with lower-surface-tension, high-silica glass (95 wt% SiO 2 ). Immiscible glass-pair composition relationships show that the immiscibility is not stable and probably represents incomplete mixing. Devitrifi cation varies and some low-silica, high-iron glasses appear to have formed Fe-rich smectite; other glass compositions have formed rapid quench textures of corundum, orthopyroxene, clinopyroxene, magnetite, K-feldspar, plagioclase, chrome-spinel, and hercynite. Hydration (H 2 O by difference) varies from ~10 wt% to essentially anhydrous; high-SiO 2 glasses tend to contain less H2O. Petrographic relationships show decomposition of pyrite and melting of pyrrhotite through the transformation series; pyrite? pyrrhotite? troilite→ iron. Spheres (~1 to ~50 μm) of quenched immiscible sulfi de melt in silicate glass show a range of compositions and include phases such as pentlandite, chalcopyrite, Ni-As, monosulfi de solid solution, troilite, and rare Ni-Fe. Other sulfi de spheres contain small blebs of pure iron and exhibit a continuum with increasing iron content to spheres that consist of pure iron with small, remnant blebs of Fe-sulfi de. The Ni-rich sulfi de phases can be explained by melting and/or concentrating targetderived Ni without requiring an asteroid impactor source component. The presence of locally unaltered glasses in these rocks suggests that in some rock volumes, isolation from postimpact hydrothermal systems was suffi cient for glass preservation. Pressure and temperature indicators suggest that, on a thin-section scale, the suevites record rapid mixing and accumulation of particles that sustained widely different peak temperatures, from clasts that never exceeded 300 ± 50 °C, to the bulk of the glasses where melted sulfi de and unmelted monazite suggest temperatures of 1500 ± 200 °C. The presence of coesite in some glass-bearing samples suggests that pressures exceeded ~3 GPa. © 2009 Geological Society of America. 2009 English 00721077 10.1130/2009.2458(20) Special Paper of the Geological Society of America 458 Geological Society of America 447-468 U.S. Geological Survey, 956 National Center, Reston, VA 20192, United States Copper compounds; Corundum; Electron probe microanalysis; Feldspar; Hydration; Iron; Magnetite; Melting; Mixing; Phosphate minerals; Positive ions; Pyrites; Silica; Silicates; Spheres; Structure (composition); Sulfur compounds; Textures, Chesapeake bay impact structures; Compositional range; Glass compositions; High silica glass; Hydrothermal system; Peak temperatures; Pressure and temperature; Spherical globules, Glass, chemical composition; crater; impact structure; marine sediment; silicate; suevite; sulfide, Chesapeake Bay; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-74949122430&doi=10.1130%2f2009.2458%2820%29&partnerID=40&md5=5ca1226aa9e9420bee23fda38c5ea263 cited By 14 H.E. Belkin J.W. Horton Jr. article Griffith2009 We estimate the static stress drop on small exhumed strike-slip faults in the Lake Edison granodiorite of the central Sierra Nevada (California). The subvertical strike-slip faults were exhumed from 4 to 15 km depth and were chosen because they are exposed in outcrop along their entire tip-to-tip lengths of 8-12 m. Slip nucleated on joints and accumulated by crystal-plastic shearing (forming quartz mylonites from early quartz vein filling in joints) and successive brittle faulting (forming epidote-bearing cataclasites). The occurrence of thin, ≤300 fim wide, pseudotachylytes along some small faults throughout the study area suggests that some, if not all, of the brittle slip on the study area faults may have been seismic. We suggest that the contribution of brittle, cataclastic slip to the total slip along the studied cataclasite-bearing small faults may be estimated by the length of epidote-filled, rhombohedral dilatational jogs (rhombochasms) distributed quasi-periodically along the length of the faults. The interpretation that slip recorded by rhombochasms occurred in single events is based on evidence that (1) epidote crystals are randomly oriented and undeformed within the rhombochasm; (2) cataclasite in principal slip zones does not include clasts of previous cataclasite, and (3) rhombochasm lengths vary systematically along the length of the faults with slip maximum occurring near the fault center, tapering to the fault tips. We thereby constrain both the rupture length and slip. On the basis of these measurements, we calculate stress drops ranging over 90-250 MPa, i.e., one to two orders of magnitude larger than typical seismological estimates for earthquakes, but similar in magnitude to seismological estimates of small (<M2) earthquakes from the San Andreas Fault Observatory at Depth (SAFOD). The slip events described in the present study occurred along small, deep-seated faults, and, given the calculated stress drops and observations that brittle faults exploited joints sealed by quartz-bearing mylonite, we conclude that these were "strong" faults. © 2009 by the American Geophysical Union. 2009 English 21699313 10.1029/2008JB005879 Journal of Geophysical Research: Solid Earth 114 Blackwell Publishing Ltd Department of Geological and Environmental Sciences, Stanford University, Stanford, CA 94305, United States; Istituto Nazionale di Geofisica e Vulcanologia, Via di Vigna Murata 605, I-00143 Roma, Italy; Dipartimento di Geoscienze, Universita di Padova, Via Giotto 1, 1-35137 Padova, Italy 2 earthquake; epidote; faulting; mylonite; quartz; seismology; shear stress; slip; strike-slip fault, California; North America; San Andreas; Sierra Nevada [California]; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-66149164465&doi=10.1029%2f2008JB005879&partnerID=40&md5=b4f6329e642cbee7db5c0a78f56977ef cited By 30 W.A. Griffith G.D. Toro G. Pennacchioni D.D. Pollard S. Nielsen article Tagle20094891 A set of 11 impact melt rock samples from the Rochechouart impact structure, France and nine impact melt rock samples from Sääksjärvi impact structure, Finland were studied for their major and trace element compositions, including the abundances of the platinum group elements. The main goal of this study was to identify the projectile type(s) responsible for the formation of these two impact structures. The results confirmed previous studies that suggested extraterrestrial contamination in both the Rochechouart and Sääksjärvi impact melt rocks. The projectile types found for Rochechouart and Sääksjärvi are quite similar, and compatible with the composition of non-magmatic iron meteorites (IA and IIIC). This interpretation is based on: identical platinum group element patterns as well as peculiar Ni/Cr, Ni/Ir and Cr/Ir ratios, which can be explained by mixing of the different components of non-magmatic iron meteorites. This result indicates that, besides ordinary chondrites, non-magmatic iron may be among the most common material impacting the Earth, as they also represent the majority of the projectiles for craters smaller that 1.5 km. The abundance of non-magmatic irons as projectiles as well as their composition (olivine, pyroxene and iron) supports the assumption that a fraction of the S-type asteroids could by related to this type of material. © 2009. 2009 10.1016/j.gca.2009.05.044 Geochimica et Cosmochimica Acta 73 4891-4906 Dept. of Geology, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium; Mineralogy, Natural History Museum, Humboldt-University Berlin, D-10099 Berlin, Germany; GeoForschungsZentrum Potsdam, D-14473 Potsdam, Germany 16 https://www.scopus.com/inward/record.uri?eid=2-s2.0-67650233378&doi=10.1016%2fj.gca.2009.05.044&partnerID=40&md5=cc40dd28e86e76701b9af8d8b1bbed3f cited By 27 R. Tagle R.T. Schmitt J. Erzinger article Vanko2009543 Core samples from the International Continental Scientific Drilling Program (ICDP)-U.S Geological Survey (USGS) Eyreville B core, located in the central crater of the Chesapeake Bay impact structure, were studied to determine the degree to which postimpact hydrothermal activity is recorded in secondary minerals and fluid inclusions. The Chesapeake Bay impact event occurred ̃35 Ma ago on the siliciclastic continental shelf of eastern North America, in up to several hundred meters of water. The combination of hot materials, such as impact melts and suevite breccias, with overlying crater-fill material and seawater is hypothesized to have led to postimpact hydrothermal circulation. Secondary minerals are distinguished from pre-impact minerals by textural features such as the presence or absence of shock metamorphic effects. Minerals in veins and cavities that are shown to have formed after the impact include secondary calcite, chalcedony, phillipsite, clinoptilolite-heulandite, mordenite, and montmorillonite. Some secondary calcite contains liquid-only fluid inclusions with trapping temperatures constrained to be less than or equal to ̃50 °C. Salinities of the inclusion fluids are mostly around 4.3 ± 1 wt% NaCl equivalent, or ̃43 ± 10 g/L total dissolved solids. This salinity is similar to that of the anomalously saline groundwater that currently exists within the crater-fill material, and that could be relict brine that originated just after the impact. © 2009 The Geological Society of America. 2009 English 00721077 10.1130/2009.2458(23) Special Paper of the Geological Society of America 458 Geological Society of America 543-557 Department of Physics, Astronomy and Geosciences, Towson University, Towson, MD 21252, United States Calcite; Clay alteration; Crystalline rocks; Groundwater; Infill drilling; Mineralogy; Sodium chloride; Zeolites, Chesapeake bay impact structures; Continental scientific drillings; Eastern north america; Hydrothermal activity; Hydrothermal alterations; Hydrothermal circulation; Total dissolved solids; U.S geological surveys, Nitrogen compounds, assessment method; breccia; crystalline rock; fluid inclusion; hydrothermal activity; hydrothermal alteration; hydrothermal circulation; hydrothermal deposit; hydrothermal system; impact structure; impactite; petrography; research program; secondary mineral; shock metamorphism; suevite, Chesapeake Bay; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-74949126684&doi=10.1130%2f2009.2458%2823%29&partnerID=40&md5=045dc6251fd625bf66017647f824a6ed cited By 4 D.A. Vanko article Zhang20091679 According to seismic, logging, core, outcrop palaeoclimate and palaeontologic data, synthetic seismogram was used to demarcate and analyze the area structure evolution characteristic, and using concept and method of sedimentology and sequence stratigraphy, four types of sequence boundaries were identified, including regional unconformity surface, exposure surface, channel scouring and eroding surface and formation stacking transformation surface, and a new supersequence boundary SB4 was also divided. The results show that Sifangtai to Mingshui formation in the north of Songliao Basin finally can be divided into one supersequence group, two supersequences(SSQ1 and SSQ2), six sequences(SQ1?SQ6) and seventy systems tracts and the high resolution sequence stratigraphic framework is also established. The rule of sediment fill and evolution in the sequence stratigraphic framework in the north of the basin is as follows: In the deposition period of sequence SQ1 to SQ3, the basin mainly develops fluvial and coastal-shallow lake facies where provenance's direction is in the direction of SN along the long axis of the basin, while in the deposition period of sequence SQ4 to SQ6, the basin mainly develops braid river delta and costal-shallow lake facies where provenance is in the direction of EW along the short axis of the basin. The basin's deposit center has also constantly migrated to the northwest from the beginning of the Sifangtai formation. Based on the comprehensive research on the reservoir-cap combination distribution of sequence stratigraphy framework and the conditions of the migration, accumulation of oil and gas show that sequence SQ1 of Sifangtai formation develops the most favorable reservoir-cap combination, and the thick bedded channel sand of the lowstand systems tract of sequence SQ1 in Da'an-Xinzhan area is the most favorable hydrocarbon accumulation area which probably develops structural-lithologic secondary hydrocarbon reservoir. Article 2009 Chinese 16727207 Zhongnan Daxue Xuebao (Ziran Kexue Ban)/Journal of Central South University (Science and Technology) 40 1679 – 1688 6 Coastal zones; Hydrocarbons; Sedimentology; Seismology; Braid river; Channel sands; Comprehensive research; Favorable hydrocarbon accumulation; High resolution; High resolution sequence stratigraphy; Hydrocarbon accumulation; Hydrocarbon reservoir; Long axis; Oil and gas; Palaeoclimate; Sequence boundary; Sequence stratigraphic framework; Sequence stratigraphy; Shallow lakes; Songliao basin; Structure evolution; Supersequence; Synthetic seismogram; Systems tracts; Stratigraphy https://www.scopus.com/inward/record.uri?eid=2-s2.0-75349094346&partnerID=40&md5=a27be4a54fdf398b790e36a6af190b94 Cited by: 9 Lei Zhang Ying-Min Wang Shu-Qing Li Jian-Hui Han Xing-Tao Zhang Yan-He Zhu Gai-Yun Wang Ting Yang article Faber2009315 Two stations monitoring concentrations of carbon dioxide and radon in soil gas (Oldřiášská and Nový Kostel) and one station monitoring flow of carbon dioxide at a mofette (Soos) have been operated in the area of the West Bohemian earthquake swarms. We present preliminary results obtained on the base of four-year observations. We found that data are not influenced considerably by barometric pressure. Although the CO2 concentration varies greatly, the long-term trends at stations Oldŕliíǎská and Nový Kostel are similar, which indicates that the CO2 flow is controlled by common geogenic processes. Also temporal trends of CO2 and Rn concentrations in soil gas at individual stations are analogous. We found diurnal variations of both CO2 concentration in soil gas and the CO2 flow at mofettes due to the earth tides. A response to tides of semi-diurnal period is insignificant in CO2 concentration and only weak in the CO2 flow. We also examined possible pre-seismic, co-seismic and post-seismic effects of the intensive 2008 earthquake swarm on the CO2 concentration at Oldčíšská and Nový Kostel, and on the CO2 flow at Soos. However, all potential indications were insignificant and there has not been proven any influence of the swarm on the CO2 concentration as well as on the CO2 flow. Nevertheless, a gradual decrease of amplitudes of diurnal variations before the swarm and the lowest amplitudes during the swarm is a noteworthy phenomenon, which might indicate the strain changes of the rock associated with earthquake swarm. © Institute of Geophysics of the ASCR, v.v.i 2009. Article 2009 English 00393169 10.1007/s11200-009-0020-z Studia Geophysica et Geodaetica 53 315 – 328 3 Bohemia; Central Europe; Czech Republic; Eurasia; Europe; amplitude; carbon dioxide; concentration (composition); diurnal variation; Earth tide; earthquake swarm; gas flow; radon; soil gas; time series analysis https://www.scopus.com/inward/record.uri?eid=2-s2.0-68349154321&doi=10.1007%2fs11200-009-0020-z&partnerID=40&md5=d886873e0ca150e9b81c7e32c295b043 Cited by: 20 Eckhard Faber Josef Horálek Alena Boušková Manfred Teschner Ulrich Koch Jürgen Poggenburg article Brigham-Grette200938 2009 English 18168957 10.2204/iodp.sd.7.05.2009 Scientific Drilling 38-39 Department of Geosciences, University of Massachusetts, Amherst, MA 01003, United States; Institute of Geology and Mineralogy, University of Cologne, Zuelpicher Str. 49a, D-50674 Cologne, Germany 7 https://www.scopus.com/inward/record.uri?eid=2-s2.0-78651547562&doi=10.2204%2fiodp.sd.7.05.2009&partnerID=40&md5=eb5db8fb63634328883dde82b832ab6e cited By 3 J. Brigham-Grette M. Melles article Schleicher2009 Mineralogical and geochemical changes in mudrock cuttings from two segments of the San Andreas Fault Observatory at Depth (SAFOD) drill hole (3066-3169 and 3292-3368 m measured depth) are analyzed in this study. Bulk rock samples and hand-picked fault-related grains characterized by polished surfaces and slickensides were investigated by X-ray diffraction, electron microscopy and geochemical analysis. The elemental changes in fault-related grains along the sampled San Andreas Fault are attributed to dissolution of detrital grains (particularly feldspar and quartz) and local precipitation of illite-smectite and/or chlorite-smectite mixed layers in fractures and veins. Assuming ZrO 2 and TiO2 to be immobile elements, systematic differences in element concentrations show that most of the elements are depleted in the fault-related grains compared to the wall rock lithology. Calculated mass loss between the bulk rock and picked fault rock ranges from 17 to 58% with a greater mass transport in the shallow trace of the sampled fault that marks the upper limit the fault core. The relatively large amount of element transport at temperatures of ∼110-114°C recorded throughout the core requires extensive fluid circulation during faulting. Whereas dissolution/precipitation may be partly induced by the disequilibrium between fluids and rocks during diagenetic processes, stress-induced dissolution at grain contacts is proposed as the main mechanism for extensive mineral transformation in the fault rocks and localization of neomineralization along grain interface slip surfaces. Copyright 2009 by the American Geophysical Union. 2009 English 21699313 10.1029/2008JB006092 Journal of Geophysical Research: Solid Earth 114 Blackwell Publishing Ltd Geozentrum Nordbayern, Friedrich Alexander Universität Erlangen-Nürnberg, Erlangen, Germany; Department of Geological Sciences, University of Michigan, 1100 N. University Avenue, Ann Arbor, MI 48109-1005, United States; Institut fur Geographie und Geologie, Ernst Moritz Arndt Universität Greifswald, Friedrich-Ludwig-Jahn-Strasse 17a, D-17487 Greifswald, Germany 4 diagenesis; disequilibrium; dissolution; electron microscopy; faulting; fluid-structure interaction; geochemistry; lithology; mass transfer; mineralization; mudstone; observatory; precipitation (chemistry); titanium; X-ray diffraction; zircon, California; North America; San Andreas; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-69249092264&doi=10.1029%2f2008JB006092&partnerID=40&md5=32f6b266705c75fe9efcc8bdac8cd235 cited By 37 A.M. Schleicher S.N. Tourscher L.N. Warr article Tembe2009 Analysis of field data has led different investigators to conclude that the San Andreas Fault (SAF) has either anomalously low frictional sliding strength (μ < 0.2) or strength consistent with standard laboratory tests (μ > 0.6). Arguments for the apparent weakness of the SAF generally hinge on conceptual models involving intrinsically weak gouge or elevated pore pressure within the fault zone. Some models assert that weak gouge and/or high pore pressure exist under static conditions while others consider strength loss or fluid pressure increase due to rapid coseismic fault slip. The present paper is composed of three parts. First, we develop generalized equations, based on and consistent with the Rice (1992) fault zone model to relate stress orientation and magnitude to depth-dependent coefficient of friction and pore pressure. Second, we present temperature-and pressure-dependent friction measurements from wet illite-rich fault gouge extracted from San Andreas Fault Observatory at Depth (SAFOD) phase 1 core samples and from weak minerals associated with the San Andreas Fault. Third, we reevaluate the state of stress on the San Andreas Fault in light of new constraints imposed by SAFOD borehole data. Pure talc (μ≈0.1) had the lowest strength considered and was sufficiently weak to satisfy weak fault heat flow and stress orientation constraints with hydrostatic pore pressure. Other fault gouges showed a systematic increase in strength with increasing temperature and pressure. In this case, heat flow and stress orientation constraints would require elevated pore pressure and, in some cases, fault zone pore pressure in excess of vertical stress. Copyright 2009 by the American Geophysical Union. 2009 English 21699313 10.1029/2008JB005883 Journal of Geophysical Research: Solid Earth 114 Blackwell Publishing Ltd Institute for Soil Mechanics and Rock Mechanics, Karlsruhe Institute of Technology, D-76128 Karlsruhe, Germany; Earthquake Hazards Team, U.S. Geological Survey, MS 977, 345 Middlefield Road, Menlo Park, CA 94025, United States; Department of Geosciences, State University of New York at Stony Brook, ESS Building, Stony Brook, NY 11794-2100, United States 11 drilling; fault gouge; fault zone; friction; pore pressure; San Andreas Fault; stress field, Calluna vulgaris https://www.scopus.com/inward/record.uri?eid=2-s2.0-72049090093&doi=10.1029%2f2008JB005883&partnerID=40&md5=a5ae3cda7898196688a8a89157b778ae cited By 44 S. Tembe D. Lockner T.-F. Wong article Jin20092037 Lake water, river water, and groundwater from the Lake Qinghai catchment in the northeastern Tibetan Plateau, China have been analyzed and the results demonstrate that the chemical components and 87Sr/86Sr ratios of the waters are strictly constrained by the age and rock types of the tributaries, especially for groundwater. Dissolved ions in the Lake Qinghai catchment are derived from carbonate weathering and part from silicate sources. The chemistry of Buha River water, the largest tributary within the catchment, underlain by the late Paleozoic marine limestone and sandstones, constrains carbonate-dominated compositions of the lake water, being buffered by the waters from the other tributaries and probably by groundwater. The variation of 87Sr/86Sr ratios with cation concentrations places constraint on the Sr-isotopic compositions of the main subcatchments surrounding Lake Qinghai. The relative significance of river-water sources from different tributaries (possibly groundwater as well) in controlling the Sr distribution in Lake Qinghai provides the potential to link the influence of hydrological processes to past biological and physical parameters in the lake. The potential role of groundwater input in the water budget and chemistry of the lake emphasizes the need to further understand hydrogeological processes within the Lake Qinghai system. © 2009 Springer-Verlag. Article 2009 English 14312174 10.1007/s10040-009-0480-9 Hydrogeology Journal 17 2037 – 2048 8 Asia; Buha River; China; Eurasia; Far East; Qinghai; Qinghai-Xizang Plateau; catchment; chemical weathering; geochemistry; groundwater flow; hydrochemistry; hydrogeology; isotopic composition; lake water; limestone; river water; sandstone; strontium isotope; tributary; water budget; water chemistry https://www.scopus.com/inward/record.uri?eid=2-s2.0-71049121503&doi=10.1007%2fs10040-009-0480-9&partnerID=40&md5=e4f2e19d3dda10f41ecbbaeae0ddc71b Cited by: 44 Zhangdong Jin Jimin Yu Sumin Wang Fei Zhang Yuewei Shi Chen-Feng You article Gronstal2009951 Knowledge of the deep subsurface biosphere is limited due to difficulties in recovering materials. Deep drilling projects provide access to the subsurface; however, contamination introduced during drilling poses a major obstacle in obtaining clean samples. To monitor contamination during the 2005 International Continental Scientific Drilling Program (ICDP)-U.S. Geological Survey (USGS) deep drilling of the Chesapeake Bay impact structure, four methods were utilized. Fluorescent microspheres were used to mimic the ability of contaminant cells to enter samples through fractures in the core material during retrieval. Drilling mud was infused with a chemical tracer (Halon 1211) in order to monitor penetration of mud into cores. Pore water from samples was examined using excitation-emission matrix (EEM) fl uorescence spectroscopy to characterize dissolved organic carbon (DOC) present at various depths. DOC signatures at depth were compared to signatures from drilling mud in order to identify potential contamination. Finally, microbial contaminants present in drilling mud were identified through 16S ribosomal deoxyribonucleic acid (rDNA) clone libraries and compared to species cultured from core samples. Together, these methods allowed us to categorize the recovered core samples according to the likelihood of contamination. Twenty-two of the 47 subcores that were retrieved were free of contamination by all the methods used and were subsequently used for microbiological culture and culture-independent analysis. Our approach provides a comprehensive assessment of both particulate and dissolved contaminants that could be applied to any environment with low biomass. © 2009 The Geological Society of America. 2009 English 00721077 10.1130/2009.2458(41) Special Paper of the Geological Society of America 458 Geological Society of America 951-964 Planetary and Space Sciences Research Institute, Open University, Milton Keynes, MK7 6AA, United Kingdom; U.S. Geological Survey, MS 430, 12201 Sunrise Valley Drive, Reston, VA 20192, United States; Biology Department, Old Dominion University, Norfolk, VA 23529, United States Contamination; Coremaking; Infill drilling; Mud logging; Organic carbon, Chesapeake bay impact structures; Comprehensive assessment; Contamination assessment; Continental scientific drillings; Dissolved organic carbon; Excitation emission matrices; Fluorescent micro spheres; Microbiological cultures, Core samples, assessment method; biomass; biosphere; deep drilling; dissolved organic carbon; fluorescence spectroscopy; geological survey; impact structure; microbiology; pollution monitoring; porewater; sediment core; sediment pollution; tracer, Chesapeake Bay; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-74949114892&doi=10.1130%2f2009.2458%2841%29&partnerID=40&md5=5140861b6067ba3c6eaa986bfc067d5a cited By 15 A.L. Gronstal M.A. Voytek J.D. Kirshtein N.M. Heyde M.D. Lowit C.S. Cockell article Brigham-Grette200918431 2009 English 00278424 10.1073/pnas.0910346106 Proceedings of the National Academy of Sciences of the United States of America 106 18431-18432 Department of Geosciences, University of Massachusetts, Amherst, MA 01003, United States 44 arctic climate; deglaciation; global climate; greenhouse effect; lake ecosystem; note; paleoclimate; priority journal; temperature measurement, Arctic Regions; Fresh Water; Geography; Geologic Sediments; Global Warming; Paleontology; Time Factors https://www.scopus.com/inward/record.uri?eid=2-s2.0-73249134817&doi=10.1073%2fpnas.0910346106&partnerID=40&md5=3f9554812dc15cfa7b721cebbee347c7 cited By 9 J. Brigham-Grette article 2009 Exploration Engineering (Rock &, Soil Drilling and Tunneling) 36 388-392 S1 Y. Zhu W. Wang article Nichols20091052 Cooling rates have been determined for basaltic glasses from different depths of the submarine section of the drill core recovered in the 1999 phase of Hawaii Scientific Drilling Project (HSDP2). The glasses include degassed blocky hyaloclastite clasts and undegassed pillow rims. The degassed glassy clasts were generated in subaerial or shallow submarine environments, during explosive interactions between lava and seawater, before eventual deposition under water. The volatile contents of the glassy pillow rims are consistent with eruption and quenching in water several hundred metres deep. The cooling rates have been calculated from the calorimetric properties of the glass across the glass transition. The heat capacity (cp) of each sample was measured during several cycles of heating from room temperature to temperatures above their glass transition using a differential scanning calorimeter (DSC). Their compositions did not change during the thermal treatment, a prerequisite for successful cp measurements, although the glasses with higher H2O contents became more opaque and their mid-IR spectra changed. Each cp-T path exhibits the now classic features of the glass transition; glassy and liquid states separated by a hysteresis marking the transition. After experiencing the same experimental thermal history the glass transition occurs at lower temperatures in glasses with higher H2O contents. Except for one sample, the cp-T path measured on initial heating also releases energy stored during the natural quench, which is not recovered during subsequent experimental cooling. The energy stored in the HSDP2 glasses is much less than that observed in hyperquenched natural and synthetic glasses. Even so, the Tool-Narayanaswamy enthalpy relaxation geospeedometer, usually used to determine the cooling rates in volcanic glasses, is unable to deal with this energy release. For those samples that exhibit this feature an alternative method, developed for hyperquenched glasses, is applied. This uses the energy released to calculate Tf, from which the cooling rate is calculated. The degassed blocky hyaloclastite clasts exhibit cooling rates 0.1-72.2 K s-1, while the undegassed pillow rims span 0.2-46.4 K s-1. The fastest cooling rates are consistent with the cooling of lava bodies in seawater. The wide variation for both types of glass could reflect quenching at different distances from the basalt-seawater interface. However, for the degassed hyaloclastite clasts the range could indicate that the clasts were generated by different processes operating during the explosive interaction between lava and seawater in the littoral zone. In the undegassed pillow lavas, glassy rims may have been reheated, giving rise to more complex, slower, thermal histories, as a result of latent heat released during the crystallisation of pillow interiors, or flow replenishment. Both types of glass may also have experienced reheating from succeeding flows or deposits. Compared to deep-sea limu o Pele hyaloclastite fragments, whose hyperquench rates indicate simultaneous cooling and fragmentation, the shallow blocky hyaloclastite clasts may have formed during post-cooling brittle fragmentation. © 2008 Elsevier Ltd. All rights reserved. Article 2009 English 00167037 10.1016/j.gca.2008.11.023 Geochimica et Cosmochimica Acta 73 1052 – 1066 4 basalt; calorimetry; chemical composition; clastic rock; cooling; Deep Sea Drilling Project; deposition; differential thermal analysis; experimental study; fragmentation; hyaloclastite; phase transition; pillow lava; underwater environment; volatile substance https://www.scopus.com/inward/record.uri?eid=2-s2.0-58849124776&doi=10.1016%2fj.gca.2008.11.023&partnerID=40&md5=8f7dba10642e2acbf024f9f7b824d2e2 Cited by: 34 A.R.L. Nichols M. Potuzak D.B. Dingwell article Kuo2009 The Taiwan Chelungpu-fault Drilling Project (TCDP) Hole-A recovered continuous core samples across the rupture zone of the 1999 Chi-Chi earthquake (Mw7.6). Studying in-situ chemical properties sequentially from fresh-fault-zone materials of the Chelungpu fault provides insight into possible faulting mechanisms. Distinct anomalies of mineral assemblages at the 1111-m fault zone of TCDP Hole-A are found to be: (1) A decrease in clay content within the primary slip zone (PSZ); and (2) A significant decline of illite, disappearance of chlorite and kaolinite, and spike in smectite within the PSZ. Meanwhile, features relating to melting or amorphous material in the PSZ have been observed by SEM and TEM. The results suggest that the PSZ might have experienced generation of glassy materials such as pseudotachylyte by the expense of clay minerals due to strong shear heating, then prompt alteration of pseudotachylyte into smectite. Characteristics of clay minerals and images obtained from electronic microscopes in the PSZ thus imply that pseudotachylyte possibly developed during the 1999 Chi-Chi earthquake, but quickly altered into smectite. This particular phenomenon may explain why pseudotachylyte is rarely found in exhumed hydrated fault zones. Copyright 2009 by the American Geophysical Union. 2009 English 00948276 10.1029/2009GL039269 Geophysical Research Letters 36 American Geophysical Union Department of Geosciences, National Taiwan University, No. 1, Roosevelt Road, Taipei 10617, Taiwan; Intemational Laboratory ADEPT France-Taiwan, CNRS, NSC, Taipei, Taiwan; Department of Earth Sciences, National Taiwan Normal University, Taipei, Taiwan; Institute of Applied Geosciences, National Taiwan Ocean University, 2 Pei-Ning Road, Keelung 20224, Taiwan 18 Amorphous materials; Chemical properties; Clay alteration; Earthquakes; Hydrates; Kaolinite; Silicate minerals, ChiChi earthquake; Clay content; Drilling projects; Electronic microscopes; Fault zone; Glassy materials; In-situ; Mineral assemblage; Pseudotachylytes; Rupture zone; SEM and TEM; Shear heating; Slip zones; Smectites, Minerals, amorphous medium; chemical property; Chi-Chi earthquake 1999; clay mineral; earthquake magnitude; earthquake rupture; fault zone; faulting; pseudotachylite; seismic zone; smectite, Asia; Chelungpu Fault Zone; Eurasia; Far East; Taiwan https://www.scopus.com/inward/record.uri?eid=2-s2.0-72149098406&doi=10.1029%2f2009GL039269&partnerID=40&md5=ea7ce88083b82e7884083c314c6c03a6 cited By 77 L.-W. Kuo S.-R. Song E.-C. Yeh H.-F. Chen article Zhang2009868 Cretaceous phytoplankton from the newly completed core hole (SK-1, N&S) in the central Songliao Basin was studied. The target interval is from the upper Quantou Formation of Upper Cretaceous to Mingshui Formation. Twelve genera of dinoflagellates, six of acritarcha and three of chlorophyta were identified in 588 samples from the 2300-m deep core. Ten phytoplankton assemblages have been classified: Tetranguladinium-Subtilisphaera-Botryococcus, Botryococcus-Pediastrum, Pediastrum, Dinogymniopsis-ChlamydophreUa-Vesperopsis bifurcate, Dinogymniopsis minor-Balmula, Pediastrum-Botryococcus, Schizosporis-Campenia, Kiokansium-Dinogymniopsis-Botryococcus, Dinogymniopsis-Granodiscus-Filisphaeridium and Granodiscus. According to the findings mentioned above, the age of the upper Qantou Formation is Cenomanian, the Qingshankou Formation belongs to upper Cenomanian-Turonian, the Yaojia Formation to Coniancian-Santonian age, the Nenjiang Formation is of Campanian age, and Sifangtai-Mingshui formations are referred to Maastrichtian stage. The ecology of phytoplankton is closely related to water salinity. Each type of phytoplankton is within a certain living water mass whose evolution type reflects salinity change of the Songliao Lake. The assemblages from the SK-1 indicate that water salinity changes with the cycle of freshwater-alight brackish water-brackish water-slight brackish water-freshwater in the lake. 2009 English 10009515 10.1111/j.1755-6724.2009.00125.x Acta Geologica Sinica (English Edition) 83 868-874 China University of Geosciences (Beijing), Beijing 100083, China; Jilin Technology College of Electronic Information, Jilin 132021, China 5 Acritarcha; Botryococcus; Chlorophyta; Dinophyceae; Pediastrum; Vesperopsis https://www.scopus.com/inward/record.uri?eid=2-s2.0-80053244085&doi=10.1111%2fj.1755-6724.2009.00125.x&partnerID=40&md5=325caf79b3cb6dd4a7f44be43fbb1ada cited By 7 Y. Zhang L. Bao article Gohn20091 The late Eocene Chesapeake Bay impact structure lies buried at moderate depths below Chesapeake Bay and surrounding landmasses in southeastern Virginia, USA. Numerous characteristics made this impact structure an inviting target for scientific drilling, including the location of the impact on the Eocene continental shelf, its threelayer target structure, its large size (̃85 km diameter), its status as the source of the North American tektite strewn field, its temporal association with other late Eocene terrestrial impacts, its documented effects on the regional groundwater system, and its previously unstudied effects on the deep microbial biosphere. The Chesapeake Bay Impact Structure Deep Drilling Project was designed to drill a deep, continuously cored test hole into the central part of the structure. A project workshop, funding proposals, and the acceptance of those proposals occurred during 2003-2005. Initial drilling funds were provided by the International Continental Scientific Drilling Program (ICDP) and the U.S. Geological Survey (USGS). Supplementary funds were provided by the National Aeronautics and Space Administration (NASA) Science Mission Directorate, ICDP, and USGS. Field operations were conducted at Eyreville Farm, Northampton County, Virginia, by Drilling, Observation, and Sampling of the Earth's Continental Crust (DOSECC) and the project staff during September-December 2005, resulting in two continuously cored, deep holes. The USGS and Rutgers University cored a shallow hole to 140 m in April-May 2006 to complete the recovered section from land surface to 1766 m depth. The recovered section consists of 1322 m of crater materials and 444 m of overlying postimpact Eocene to Pleistocene sediments. The crater section consists of, from base to top: basement-derived blocks of crystalline rocks (215 m); a section of suevite, impact melt rock, lithic impact breccia, and cataclasites (154 m); a thin interval of quartz sand and lithic blocks (26 m); a granite megablock (275 m); and sediment blocks and boulders, polymict, sediment-clast-dominated sedimentary breccias, and a thin upper section of stratified sediments (652 m). The cored postimpact sediments provide insight into the effects of a large continental-margin impact on subsequent coastal-plain sedimentation. This volume contains the first results of multidisciplinary studies of the Eyreville cores and related topics. The volume is divided into these sections: geologic column; borehole geophysical studies; regional geophysical studies; crystalline rocks, impactites, and impact models; sedimentary breccias; postimpact sediments; hydrologic and geothermal studies; and microbiologic studies. © 2009 The Geological Society of America. 2009 English 00721077 10.1130/2009.2458(01) Special Paper of the Geological Society of America 458 Geological Society of America 1-20 U.S. Geological Survey, 926A National Center, Reston, VA 20192, United States; Department of Lithospheric Research, University of Vienna, A-1090 Vienna, Austria; Department of Earth and Planetary Sciences, Rutgers University, Piscataway, NJ 08854-8066, United States; Museum für Naturkunde-Leibniz Institute, Humboldt University Berlin, Invalidenstrasse 43, 10115, Berlin, Germany Boreholes; Crystalline materials; Crystalline rocks; Geophysics; Groundwater; Infill drilling; NASA; Sedimentary rocks; Sedimentology; Structural geology, Chesapeake bay impact structures; Continental scientific drillings; Continental shelves; Pleistocene sediments; Regional groundwater; Scientific drilling; Temporal association; U.s. geological surveys, Sediments, continental margin; continental shelf; deep drilling; Eocene; impact structure; Pleistocene; sedimentation, Chesapeake Bay; United States; Virginia https://www.scopus.com/inward/record.uri?eid=2-s2.0-74949128570&doi=10.1130%2f2009.2458%2801%29&partnerID=40&md5=b2774daedcac94d70d36dd148646b7a3 cited By 16 G.S. Gohn C. Koeberl K.G. Miller W.U. Reimold article Stolper20094 The Hawaii Scientific Drilling Project drilled and cored two holes in Hilo, Hawaii, the deeper reaching a depth of 3508 mbsl, and it retrieved a total of 4600 meters of rock core (525 meters from the Mauna Loa volcano and the remainder from the Mauna Kea volcano). The Mauna Loa core extends the continuous lava stratigraphy of that volcano back to 100 ka and reveals major changes in lava geochemistry over that time period. The Mauna Kea core spans an age range from about 200 ka to perhaps 700 ka, and when combined with surface outcrops, it provides a 700-kyr record of the lava output from a single volcano. During the time covered by the lavas from the core, the volcano drifted some 60-80 km across the melting region of the Hawaiian mantle plume, and therefore the HSDP rock core provides the first systematic cross-sectional sampling of a deep mantle plume. The geochemical characterization of the core, which involved an international team of forty scientists over a period of fifteen years provides information about mantle plume structure and ultimately about the deepest parts of the Earth's mantle. The study of the lava core (which still continues) has provided unprecedented information about the internal structure of a large oceanic volcano and the time scale over which volcanoes grow. The hole also provides an intriguing glimpse of a complex subsurface hydrological regime that differs greatly from the generalized view of ocean island hydrology. Drilling conditions were favorable in the subaerial parts of the volcanic section, where coring was generally fast and efficient. The submarine part of the lava section, made up primarily of volcanogenic sediments and pillow lavas, proved considerably more difficult to drill. Some of the difficulties and considerable additional expense were due to pressurized aquifers at depth and a few critical mistakes made while setting casing. Even with the more difficult conditions, the project retrieved about 2400 meters of nearly continuous core from the submarine section of Mauna Kea. Overall, the HSDP project was highly successful even though the original target depth was about 20% deeper than the final hole depth. As expected, the project results answer several important questions about oceanic volcanoes, mantle plumes, and ocean island water resources, but they raise many more that might be addressed with further moderate-depth drilling in other Hawaiian volcanoes. 2009 English 18168957 10.2204/iodp.sd.7.02.2009 Scientific Drilling 4-14 Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, United States; Department of Earth and Planetary Science, University of California Berkeley, Earth Sciences Division, Berkeley, CA 94720, United States; Center for Study of Active Volcanoes, University of Hawaii at Hilo, 200 West Kawili Street, Hilo, HI 96720, United States 7 Deep drillings; Earth's mantles; Geochemical characterizations; Hole depths; Hydrological regimes; Internal structures; International teams; Mantle plumes; Mauna Loa; Oceanic volcanoes; Pillow lavas; Rock cores; Scientific drillings; Time periods; Time-scale; Volcanogenic sediments, Aquifers; Hydrogeology; Ocean engineering; Oceanography; Offshore oil wells; Rock drilling; Stratigraphy; Submarines; Thermal plumes; Water; Water resources, Volcanoes https://www.scopus.com/inward/record.uri?eid=2-s2.0-78651564480&doi=10.2204%2fiodp.sd.7.02.2009&partnerID=40&md5=aa9d7c4f9af6f8b1284d60673a3412be cited By 40 E.W. Stolper D.J. DePaolo D.M. Thomas article Townend200975 2009 English 18168957 10.5194/sd-8-75-2009 Scientific Drilling Integrated Ocean Drilling Program 75-82 School of Geography, Environment, and Earth Sciences, Victoria University of Wellington, P.O. Box 600, Wellington, New Zealand; GNS Science, P.O. Box 30368, Lower Hutt, New Zealand; Department of Geology, University of Otago, P.O. Box 56, Dunedin, New Zealand 8 https://www.scopus.com/inward/record.uri?eid=2-s2.0-77954475725&doi=10.5194%2fsd-8-75-2009&partnerID=40&md5=9353c507ae85591fde9fa505c3ef56af cited By 51 J. Townend R. Sutherland V. Toy article Xu2009204 The Chinese Continental Scientific Drilling (CCSD) deep borehole, which reached a depth of 5158 m in the Sulu ultrahigh-pressure (UHP) metamorphic terrane, provides a new window into the deep root of a continent-continent collision belt, and the tectonic processes by which supracrustal material is recycled into the mantle by subduction and then uplifted to the surface. Major research themes of the CCSD project were to: (1) determine the three-dimensional composition, structure and geophysical character of the deep root of this orogenic belt; (2) investigate the nature and timing of the UHP metamorphism; (3) investigate the processes of crust-mantle interaction involved in the formation and exhumation of the UHP rocks; (4) study the process of fluid circulation and mineralization during subduction and exhumation; (5) study the rheological properties of the various rocks during subduction and exhumation; (6) develop and refine dynamic models for deep subduction and exhumation of crustal rocks, and (7) establish a long-term, natural laboratory for the study of present-day crustal dynamics (e.g., stress, strain, fluid activity). The CCSD has developed precise oriented profiles of the main borehole in terms of lithology, geochemistry, oxygen isotopes, zircon SHRIMP U-Pb ages, 40Ar-39Ar ages, deformation, rheology, mineralization, physical properties of the rocks, petrophysical logs, seismic reflections and underground fluids. The present paper summarizes the integrated research results of this project, especially the new findings concerning the deep root of a continent-continent collision. © 2009 Elsevier B.V. All rights reserved. Article 2009 English 00401951 10.1016/j.tecto.2009.02.029 Tectonophysics 475 204 – 219 2 Asia; China; Eurasia; Far East; Sulu Belt; Isotopes; Lead; Lithology; Mineralogy; Oxygen; Rheology; Rocks; Silicate minerals; Tectonics; Zircon; Chinese Continental Scientific Drilling (CCSD); Continent collisions; Crustal rocks; Deep boreholes; Deep root of a continent-continent collision belt; Deep roots; Fluid circulation; Integrated research; Natural laboratories; Orogenic belts; Oxygen isotopes; Petrophysical; Rheological property; Scientific drilling; Seismic reflections; Sulu HP-UHP metamorphic terrane; Tectonic process; U-Pb ages; UHP metamorphism; Ultrahigh pressure; Ultrahigh-pressure metamorphic terranes; Chinese Continental Scientific Drilling Project; continental collision; exhumation; mineralization; orogenic belt; subduction; tectonic setting; ultrahigh pressure metamorphism; uplift; Drilling https://www.scopus.com/inward/record.uri?eid=2-s2.0-70349126266&doi=10.1016%2fj.tecto.2009.02.029&partnerID=40&md5=c8617fdd523a75666d2e72a4fd642622 Cited by: 79 Zhiqin Xu Wencai Yang Shaocheng Ji Zeming Zhang Jingsui Yang Qin Wang Zhemin Tang article GAO2009314 The first member of the Qingshankou Formation recovered by CCSD-SK-Is borehole (China Cretaceous Continental Scientific Drilling-SongkeI-the south borehole) is 81.41 m long, and the recovery of cores is 100%. The age of the member is approximately Turonian. The sequence and process of lithology-lithofacies and cyclic stratigraphy were revealed by a detailed core description. 6 rock types (mudstone, dolomite, marl, limestone, ostracode limestone, and volcanic ash) comprise the sedimentary strata. Deposition occurred in a deep lake, including 6 sedimentary microfacies: mudstone, sandy turbidite, dolomite, marl, limestone, and volcanic ash microfacies. The first member of the Qingshankou Formation represents 81 meter-scale cycles (sixth-order cycle), 25 fifth-order cycles, 6 fourth-order cycles, and 2 third-order cycles. The occurrence and detailed description of mudstone, dolomite, and volcanic ash are of significance for the study of anoxic events, the source rock development, and the potential linkage between lake-marine depositional events. © 2009 China University of Geosciences (Beijing) and Peking University. 2009 English 18725791 10.1016/S1872-5791(08)60081-0 Dixue Qianyuan/ Earth Science Frontiers 16 314-323 College of Earth Sciences, Jilin University, Changchun, 130061, China; School of Earth Sciences and Resources, China University of Geosciences (Beijing), Beijing, 100083, China; Institute of Exploration and Development, Daqing Oilfield Company Ltd., Daqing, 163712, China; Geological Logging Branch, Daqing Oilfield Company Ltd., Daqing, 163411, China 2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-71049148452&doi=10.1016%2fS1872-5791%2808%2960081-0&partnerID=40&md5=c5759aad9c9427e05fbc550628abbca0 cited By 25 Y. Gao P. Wang R. Cheng G. Wang X. Wan H. Wu S. Wang W. LIANG article WANG2009324 The Quantou Formation recovered by CCSD-SK-Is borehole (China Cretaceous Continental Scientific Drilling-SongkeI-the south borehole) is 132.07 m long and the recovery of cores is 100%. The sequence and process of lithology-lithofacies and cyclostratigraphy are revealed by a detailed core description. Nine rock types and three kinds of sedimentary facies including meandering river, shallow lake, and delta front are recognized from the drilling core, there are ten sedimentary microfacies, which are point bar, natural levee, crevasse splay, crevasse channel, floodplain, flood lake, distributary mouth bar, interdistributary bay, mudstone of still water, and turbidite. The Quantou Formation represents seventy-six meter-scale cycles (sixth-order cycle), twenty-five fifth-order cycles, eight fourth-order cycles, and two third-order cycles. Meticulously depicted (centimeter level) continental red beds of the third and the fourth members of Quantou Formation will be a potential formulation profile for the studies of Cretaceous global oxygen-enriched events. The reservoir sandstones of the third and the fourth members were developed basin-wide as an inevitable product before the Songliao Basin was depressed or sagged on a large scale. The period of the third and the fourth members of Quantou Formation is a stage between the development of the fault basin and the sag basin on a large scale. © 2009 China University of Geosciences (Beijing) and Peking University. Article 2009 English 18725791 10.1016/S1872-5791(08)60078-0 Dixue Qianyuan/ Earth Science Frontiers 16 324 – 338 College of Earth Sciences, Jilin University, Changchun, 130061, China; School of Earth Sciences and Resoures, China University of Geosciences (Beijing), Beijing, 100083, China; Institute of Exploration and Development, Daqing Oilfield Company Ltd., Daqing, 163712, China 2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-71049190112&doi=10.1016%2fS1872-5791%2808%2960078-0&partnerID=40&md5=7aef1d4bf1419b975da31963aa3e833b Cited by: 23 Guodong Wang Rihui Cheng Pujun Wang Youfeng Gao Chengshan Wang Yanguang Ren Qinghua Huang article Ormö2009617 Collapse and inward slumping of unconsolidated sedimentary strata expanded the Chesapeake Bay impact structure far beyond its central basement crater. During crater collapse, sediment-loaded water surged back to fill the crater. Here, we analyze clast frequency and granulometry of these resurge deposits in one core hole from the outermost part of the collapsed zone (i.e., Langley) as well as a core hole from the moat of the basement crater (i.e., Eyreville A). Comparisons of clast provenance and flow dynamics show that at both locations, there is a clear change in clast frequency and size between a lower unit, which we interpret to be dominated by slumped material, and an upper, water-transported unit, i.e., resurge deposit. The contribution of material to the resurge deposit was primarily controlled by stripping and erosion. This includes entrainment of fallback ejecta and sediments eroded from the surrounding seafloor, found to be dominant at Langley, and slumped material that covered the annular trough and basement crater, found to be dominant at Eyreville. Eyreville shows a higher content of crystalline clasts than Langley. There is equivocal evidence for an anti-resurge from a collapsing central water plume or, alternatively, a second resurge pulse, as well as a transition into oscillating resurge. The resurge material shows more of a debris-flow-like transport compared to resurge deposits at some other marine target craters, where the ratio of sediment to water has been relatively low. This result is likely a consequence of the combination of easily disaggregated host sediments and a relatively shallow target water depth. © 2009 The Geological Society of America. 2009 English 00721077 10.1130/2009.2458(27) Special Paper of the Geological Society of America 458 Geological Society of America 617-632 Centro de Astrobiología, Consejo Superior de Investigaciones Cientificas, Instituto Nacional de Tecnica Aeroespacial, Torrejón de Ardoz, Spain; Nordic Volcanological Center, University of Iceland, Reykjavík, Iceland; U.S. Geological Survey, 926A National Center, Reston, VA 20192, United States Buildings; Sediments, Chesapeake bay impact structures; Debris flows; Flow dynamics; Granulometries; Sea floor; Sedimentary strata; Shallow targets; Water depth, Deposits, clast; comparative study; crater; debris flow; entrainment; frequency-magnitude distribution; granulometry; provenance; sediment transport; sedimentary structure; unconsolidated medium, Chesapeake Bay; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-74949102199&doi=10.1130%2f2009.2458%2827%29&partnerID=40&md5=2e5abce2c350a4c28e8f283c75d0fa7b cited By 25 J. Ormö E. Sturkell J.W. Horton Jr. D.S. Powars L.E. Edwards article McGarr20092815 For one week during September 2007, we deployed a temporary network of field recorders and accelerometers at four sites within two deep, seismically active mines. The ground-motion data, recorded at 200 samples/sec, are well suited to determining source and ground-motion parameters for the mining-induced earthquakes within and adjacent to our network. Four earthquakes with magnitudes close to 2 were recorded with high signal/noise at all four sites. Analysis of seismic moments and peak velocities, in conjunction with the results of laboratory stick-slip friction experiments, were used to estimate source processes that are key to understanding source physics and to assessing underground seismic hazard. The maximum displacements on the rupture surfaces can be estimated from the parameter Rv, where v is the peak ground velocity at a given recording site, and R is the hypocentral distance. For each earthquake, the maximum slip and seismic moment can be combined with results from laboratory friction experiments to estimate the maximum slip rate within the rupture zone. Analysis of the four M 2 earthquakes recorded during our deployment and one of special interest recorded by the in-mine seismic network in 2004 revealed maximum slips ranging from 4 to 27 mm and maximum slip rates from 1.1 to 6:3 m=sec. Applying the same analyses to an M 2.1 earthquake within a cluster of repeating earthquakes near the San Andreas Fault Observatory at Depth site, California, yielded similar results for maximum slip and slip rate, 14 mm and 4:0 m=sec. 2009 English 00371106 10.1785/0120080336 Bulletin of the Seismological Society of America 99 2815-2824 U.S. Geological Survey, MS 977 345 Middlefield Rd. Menlo Park, California 94025, United States; Council for Scientific and Industrial Research Natural Resources and Environmental Unit, P.O. Box 91230, Auckland Park 2006, South Africa 5 Broadband records; California; Deep gold mines; Ground motion parameters; Ground-motion; Hypocentral distance; Maximum displacement; Maximum slip; Peak ground velocity; Peak velocities; Repeating earthquake; Rupture surface; Rupture zone; San Andreas Fault; Seismic hazards; Seismic moment; Seismic networks; Slip rates; Source process; Stick-slip friction; Temporary networks, Experiments; Friction; Gold mines; Mines; Mining; Parameter estimation; Risk assessment; Slip forming; Tectonics, Earthquakes, earthquake catalogue; earthquake hypocenter; earthquake magnitude; gold mine; ground motion; mining-induced seismicity; seismic hazard; seismic moment; slip rate, California; North America; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-70349873690&doi=10.1785%2f0120080336&partnerID=40&md5=eadc13c48dee1062809d2dd7a84c75f7 cited By 16 A. McGarr M. Boettcher J.B. Fletcher R. Sell M.J.S. Johnston R. Durrheim S. Spottiswoode A. Milev article CHENG2009140 The Yaojia Formation recovered by CCSD-SK-Is borehole (China Cretaceous Continental Scientific Drilling-SongkeI-the south borehole) is 157.67 m long and 99.96% of cores recovery. The age of the formation corresponds with a range from the Santonian to the early Campanian. The sequences and processes of lithology-lithofacies and cyclic stratigraphy are revealed by a detailed core description. Eleven rock types and three kinds of sedimentary subfacies, including shallow lake, deep lake, and delta front, are recognized from the drilling core. There are eleven sedimentary microfacies including dolostone, argillaceous limestone, shallow lake turbidite, deep lake turbidite, subaqueous mouth bar, distal bar, sheet sandstone, subaqueous distributary bay, slump deposits, shallow lake mudstone, and deep lake mudstone. The Yaojia Formation represents one hundred and fifty-one meter-scale cycles (sixth-order cycle), forty-five fifth-order cycles, nine fourth-order cycles, and three third-order cycles. Meticulous depiction (centimeter level) of the whole Formation provides an approach to study its sedimentary process with high precision. The red beds with a thickness of 43% in the Yaojia Formation, being one of fewer continental red beds depicted meticulously in the world, will become a standard of potential formulation section for the studies of Cretaceous global oxygen-enriched events. © 2009 China University of Geosciences (Beijing) and Peking University. 2009 English 18725791 10.1016/S1872-5791(08)60077-9 Dixue Qianyuan/ Earth Science Frontiers 16 140-151 College of Earth Sciences, Jilin University, Changchun, 130061, China; Institute of Exploration and Development, Daqing Oilfield Company Ltd., Daqing, 163712, China; School of Earth Sciences and Resoures, China University of Geosciences (Beijing), Beijing, 100083, China 2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-71049165593&doi=10.1016%2fS1872-5791%2808%2960077-9&partnerID=40&md5=dfa54f4bc3b0cdac010356259264b56b cited By 23 R. Cheng G. Wang P. Wang Y. Gao Y. Ren C. Wang S. Zhang Q. Wang article Vanko2009543 Core samples from the International Continental Scientific Drilling Program (ICDP)-U.S Geological Survey (USGS) Eyreville B core, located in the central crater of the Chesapeake Bay impact structure, were studied to determine the degree to which postimpact hydrothermal activity is recorded in secondary minerals and fluid inclusions. The Chesapeake Bay impact event occurred ̃35 Ma ago on the siliciclastic continental shelf of eastern North America, in up to several hundred meters of water. The combination of hot materials, such as impact melts and suevite breccias, with overlying crater-fill material and seawater is hypothesized to have led to postimpact hydrothermal circulation. Secondary minerals are distinguished from pre-impact minerals by textural features such as the presence or absence of shock metamorphic effects. Minerals in veins and cavities that are shown to have formed after the impact include secondary calcite, chalcedony, phillipsite, clinoptilolite-heulandite, mordenite, and montmorillonite. Some secondary calcite contains liquid-only fluid inclusions with trapping temperatures constrained to be less than or equal to ̃50 °C. Salinities of the inclusion fluids are mostly around 4.3 ± 1 wt% NaCl equivalent, or ̃43 ± 10 g/L total dissolved solids. This salinity is similar to that of the anomalously saline groundwater that currently exists within the crater-fill material, and that could be relict brine that originated just after the impact. © 2009 The Geological Society of America. 2009 10.1130/2009.2458(23) Special Paper of the Geological Society of America 458 543-557 Department of Physics, Astronomy and Geosciences, Towson University, Towson, MD 21252, United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-74949126684&doi=10.1130%2f2009.2458%2823%29&partnerID=40&md5=045dc6251fd625bf66017647f824a6ed cited By 4 D.A. Vanko article Litt20091555 Lake Van is the fourth largest terminal lake in the world (volume 607 km3, area 3570 km2, maximum depth 460 m), extending for 130 km WSW-ENE on the Eastern Anatolian High Plateau, Turkey. The sedimentary record of Lake Van, partly laminated, has the potential to obtain a long and continuous continental sequence that covers several glacial-interglacial cycles (ca 500 kyr). Therefore, Lake Van is a key site within the International Continental Scientific Drilling Program (ICDP) for the investigation of the Quaternary climate evolution in the Near East ('PALEOVAN'). As preparation for an ICDP drilling campaign, a site survey was carried out during the past years. We collected 50 seismic profiles with a total length of ∼850 km to identify continuous undisturbed sedimentary sequences for potential ICDP locations. Based on the seismic results, we cored 10 different locations to water depths of up to 420 m. Multidisciplinary scientific work at positions of a proposed ICDP drill site included measurements of magnetic susceptibility, physical properties, stable isotopes, XRF scans, and pollen and spores. This core extends back to the Last Glacial Maximum (LGM), a more extended record than all the other Lake Van cores obtained to date. Both coring and seismic data do not show any indication that the deepest part of the lake (Tatvan Basin, Ahlat Ridge) was dry or almost dry during past times. These results show potential for obtaining a continuous undisturbed, long continental palaeoclimate record. In addition, this paper discusses the potential of 'PALEOVAN' to establish new results on the dynamics of lake level fluctuations, noble gas concentration in pore water of the lake sediment, history of volcanism and volcanic activities based on tephrostratigraphy, and paleoseismic and earthquake activities. © 2009 Elsevier Ltd. All rights reserved. 2009 English 02773791 10.1016/j.quascirev.2009.03.002 Quaternary Science Reviews 28 1555-1567 Steinmann Institute of Geology, Mineralogy and Palaeontology, University of Bonn, Nussallee 8, 53115 Bonn, Germany; Leibniz Institute of Marine Sciences (IFM-GEOMAR), Wischhofstr. 1-3, 24148 Kiel, Germany; Swiss Federal Institute of Aquatic Science and Technology (Eawag), Ueberlandstr. 133, 8600 Dübendorf, Switzerland; Department of Geology, University of Yüzüncü Yil, Zeve Campus, 65080 Van, Turkey; Istanbul Technical University, Geology Department, Maslak, 34469 Istanbul, Turkey; Alfred Wegner Institute for Polar and Marine Research, PO-Box 120161, 27515 Bremerhaven, Germany 15-16 Drill sites; Earthquake activity; Glacial-interglacial cycles; Lake level fluctuations; Lake sediments; Last Glacial Maximum; New results; Noble gas; Palaeoclimate; Pore waters; Quaternary climate; Scientific drilling; Sedimentary records; Sedimentary sequence; Seismic data; Seismic profiles; Site surveys; Stable isotopes; Tephrostratigraphy; Terminal lakes; Total length; Volcanic activities; Water depth, Arctic engineering; Drilling; Engineering geology; Glacial geology; Inert gases; Magnetic susceptibility; Sedimentology; Seismic waves; Seismology; Surveys; Water, Lakes, climate change; concentration (composition); drilling; geological record; glacial-interglacial cycle; Last Glacial Maximum; noble gas; paleoclimate; paleoseismicity; porewater; research program; seismic property, Eurasia; Lake Van; Turkey, Bacteria (microorganisms) https://www.scopus.com/inward/record.uri?eid=2-s2.0-67349229533&doi=10.1016%2fj.quascirev.2009.03.002&partnerID=40&md5=85dd867c734ba24607b4b3445acd8f2e cited By 165 T. Litt S. Krastel M. Sturm R. Kipfer S. Orcen G. Heumann S.O. Franz U.B. Ülgen article Wang20091178 Interlayers of mugearite are recognized within lacustrine mudstone of the Upper Cretaceous Qingshankou Formation (K2qn) in the Songliao basin (SB) of Northeast China. Precise 40 Ar/39Ar plateau age of 88. 0 ±0. 3 Ma is obtained for the mugearite, interpreted as a Late Cretaceous, Coniacian stage. The volcanic rocks are characterized by glassy matrix and porphyritic texture. Phenocrysts are olivine, augite and plagioclase. The rocks are rich in Na, Al, LREE ( σ LREE/ σHREE = g 0 ∼ 9. 7) and LILE (e. g. U, Th, Pb, Rb, Sr and Ba) , with high Rb/Sr ratios, low Sm/Nd ratios and the δEu value ranges from 0. 95 to 1. 36. The volcanics have also high Mg# values (0. 61 ∼ 0. 64) , high Ox° values (0. 62 ∼ 0. 68) , and low MDI values (3.4 ∼ 5.3). Standard mineral pressure plot coupled with MgO/Al2 03 ratios indicate a depth of ≥ 60km for the magma chamber. Hereby, the magma originates from enriched mantle, turns to be intraplate rift volcanism as a result of maximal transtension cutting through the crust. The volcanic activities have two effects on oil & gas, accelerating hydrocarbon generation owing to the rising regional heat flow, and resulting in biolithite sediments of important source rocks owing to the local reef-building environment. Three factors involved in the volcanism are favorable for petroleum accumulation, including drag structures beneath, topographic highs above and turbidites around the volcanic rocks. Article 2009 Chinese 10000569 Acta Petrologica Sinica 25 Science Press 1178 – 1190 5 Asia; China; Eurasia; Far East; Songliao Basin; Calluna vulgaris; Coniacian; Geochemistry; Hydrocarbons; Lead; Rocks; Rubidium; Silicate minerals; Volcanoes; Building environment; Cretaceous qingshankou formation; Geochemical features; Hydrocarbon generation; Mugearite; Petroleum accumulations; Songliao basin; Volcanic activities; argon isotope; basin evolution; Cretaceous; geochemistry; geochronology; heat flow; hydrocarbon generation; magma chamber; mudstone; petroleum; volcanic rock; volcanism; Volcanic rocks https://www.scopus.com/inward/record.uri?eid=2-s2.0-84977992454&partnerID=40&md5=a63c538843e2663d8109804564914bca Cited by: 36 Pu Jun Wang You Feng Gao Yan Guang Ren Wan Zhu Liu Jian Guang Zhang article Wagner2009407 Lake Ohrid is considered to be of Pliocene origin and is the oldest extant lake in Europe. A 1,075-cm-long sediment core was recovered from the southeastern part of the lake, from a water depth of 105 m. The core was investigated using geophysical, granulometric, biogeochemical, diatom, ostracod, and pollen analyses. Tephrochronology and AMS radiocarbon dating of plant macrofossils reveals that the sediment sequence spans the past ca. 39,500 years and features a hiatus between ca. 14,600 and 9,400 cal. year BP. The Pleistocene sequence indicates relatively stable and cold conditions, with steppe vegetation in the catchment, at least partial winter ice-cover of the lake, and oxygenated bottom waters at the coring site. The Holocene sequence indicates that the catchment vegetation had changed to forest dominated by pine and summer-green oak. Several of the proxies suggest the impact of abrupt climate oscillations such as the 8.2 or 4.0 ka event. The observed changes, however, cannot be related clearly to a change in temperature or humidity. Human impact started about 5,000 cal. year BP and increased significantly during the past 2,400 years. Water column mixing conditions, inflow from subaquatic springs, and human impact are the most important parameters influencing internal lake processes, notably affecting the composition and characteristics of the sediments. © 2008 Springer Science+Business Media B.V. Article 2009 English 09212728 10.1007/s10933-008-9234-2 Journal of Paleolimnology 41 407 – 430 3 Eurasia; Europe; Lake Ohrid; Southern Europe; Bacillariophyta; Ostracoda; anthropogenic effect; diatom; environmental change; fossil; ostracod; paleolimnology; palynology; Quaternary; radiocarbon dating; sediment core; sedimentary sequence; steppe; tephrochronology https://www.scopus.com/inward/record.uri?eid=2-s2.0-65749102303&doi=10.1007%2fs10933-008-9234-2&partnerID=40&md5=214970cec712b96e87ded4e12c0a9cf4 Cited by: 116 Bernd Wagner André F. Lotter Norbert Nowaczyk Jane M. Reed Antje Schwalb Roberto Sulpizio Verushka Valsecchi Martin Wessels Giovanni Zanchetta article Schulte20091180 An up to ∼2-cm thick Chicxulub ejecta deposit marking the Cretaceous-Paleogene (K-Pg) boundary (the "K-T" boundary) was recovered in six holes drilled during ODP Leg 207 (Demerara Rise, tropical western Atlantic). Stunning features of this deposit are its uniformity over an area of 30 km2 and the total absence of bioturbation, allowing documentation of the original sedimentary sequence. High-resolution mineralogical, petrological, elemental, isotopic (Sr-Nd), and rock magnetic data reveal a distinct microstratigraphy and a range of ejecta components. The deposit is normally graded and composed predominantly of rounded, 0.1- to max. 1-mm sized spherules. Spherules are altered to dioctahedral aluminous smectite, though occasionally relict Si-Al-rich hydrated glass is also present, suggesting acidic precursor lithologies. Spherule textures vary from hollow to vesicle-rich to massive; some show in situ collapse, others include distinct Fe-Mg-Ca-Ti-rich melt globules and lath-shaped Al-rich quench crystals. Both altered glass spherules and the clay matrix (Site 1259B) display strongly negative εNdT = 65 Ma values (-17) indicating uptake of Nd from contemporaneous ocean water during alteration. Finally, Fe-Mg-rich spherules, shocked quartz and feldspar grains, few lithic clasts, as well as abundant accretionary and porous carbonate clasts are concentrated in the uppermost 0.5-0.7 mm of the deposit. The carbonate clasts display in part very unusual textures, which are interpreted to be of shock-metamorphic origin. The preservation of delicate spherule textures, normal grading with lack of evidence for traction transport, and sub-millimeter scale compositional trends provide evidence for this spherule deposit representing a primary air-fall deposit not affected by significant reworking. The ODP Leg 207 spherule deposit is the first known dual-layer K-Pg boundary in marine settings; it incorporates compositional and stratigraphic aspects of both proximal and distal marine sites. Its stratigraphy strongly resembles the dual-layer K-Pg boundary deposits in the terrestrial Western Interior of North America (although there carbonate phases are not preserved). The occurrence of a dual ejecta layer in these quite different sedimentary environments - separated by several thousands of kilometers - provides additional evidence for an original sedimentary sequence. Therefore, the layered nature of the deposit may document compositional differences between ballistic Chicxulub ejecta forming the majority of the spherule deposit, and material falling out from the vapor (ejecta) plume, which is concentrated in the uppermost part. © 2008 Elsevier Ltd. All rights reserved. 2009 10.1016/j.gca.2008.11.011 Geochimica et Cosmochimica Acta 73 1180-1204 GeoZentrum Nordbayern, Universität Erlangen-Nürnberg, Schlossgarten 5, D-91054 Erlangen, Germany; Institut für Planetologie, Universität Münster, D-48149 Muenster, Germany; Bruker AXS Microanalysis GmbH, Schwarzschildstr. 12, D-12489 Berlin, Germany; Institut für Mineralogie, Universität Münster, D-48149 Muenster, Germany; Geologisches Institut der Universität Karlsruhe, Strukturgeologie und Tektonophysik, D-76187 Karlsruhe, Germany; Department of Geological Sciences, University of Missouri, Columbia, MO 65211, United States; Department of Geology, Mineralogy and Geophysics, Ruhr-Universität Bochum, D-44801 Bochum, Germany 4 https://www.scopus.com/inward/record.uri?eid=2-s2.0-58549085746&doi=10.1016%2fj.gca.2008.11.011&partnerID=40&md5=77108d71476736120eec21f9eaf0ca86 cited By 45 P. Schulte A. Deutsch T. Salge J. Berndt A. Kontny K.G. MacLeod R.D. Neuser S. Krumm article Kenkmann2009571 The combination of petrographic analysis of drill core from the recent International Continental Scientific Drilling Program (ICDP)-U.S Geological Survey (USGS) drilling project and results from numerical simulations provides new constraints for reconstructing the kinematic history and duration of different stages of the Chesapeake Bay impact event. The numerical model, in good qualitative agreement with previous seismic data across the crater, is also roughly consistent with the stratigraphy of the new borehole. From drill core observations and modeling, the following conclusions can be drawn: (1) The lack of a shock metamorphic overprint of cored basement lithologies suggests that the drill core might not have reached the parautochthonous shocked crater floor but merely cored basement blocks that slumped off the rim of the original cavity into the crater during crater modification. (2) The sequence of polymict lithic breccia, suevite, and impact melt rock (1397-1551 m) must have been deposited prior to the arrival of the 950-m-thick resurge and avalanche-delivered beds and blocks within 5-7 min after impact. (3) This short period for transportation and deposition of impactites may suggest that the majority of the impactites of the Eyreville core never left the transient crater and was emplaced by ground surge. This is in accordance with observations of impact breccia fabrics. However, the uppermost part of the suevite section contains a pronounced component of airborne material. (4) Limited amounts of shock-deformed debris and melt fragments also occur throughout the Exmore beds. Shard-enriched intervals in the upper Exmore beds indicate that some material interpreted to be part of the hot ejecta plume was incorporated and dispersed into the upper resurge deposits. This suggests that collapse of the ejecta plume was contemporaneous with the major resurge event(s). Modeling indicates that the resurge flow should have been concluded some 20 min after impact; hence, this also likely marked the end of the major episode of deposition from the ejecta plume. © 2009 The Geological Society of America. 2009 10.1130/2009.2458(25) Special Paper of the Geological Society of America 458 571-585 Museum für Naturkunde-Leibniz Institute, Humboldt University Berlin, Invalidenstrasse 43, 10115 Berlin, Germany; Impact and Astromaterials Research Centre, Department of Earth Science and Engineering, Imperial College London, London, SW7 2AZ, United Kingdom; Lunar and Planetary Institute, 3600 Bay Area Boulevard, Houston, TX 77058, United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-74949105414&doi=10.1130%2f2009.2458%2825%29&partnerID=40&md5=21bb78a881f3fc2407033566586ddc4d cited By 31 T. Kenkmann G.S. Collins A. Wittmann K. Wünnemann W.U. Reimold H.J. Melosh article Kenkmann2009571 The combination of petrographic analysis of drill core from the recent International Continental Scientific Drilling Program (ICDP)-U.S Geological Survey (USGS) drilling project and results from numerical simulations provides new constraints for reconstructing the kinematic history and duration of different stages of the Chesapeake Bay impact event. The numerical model, in good qualitative agreement with previous seismic data across the crater, is also roughly consistent with the stratigraphy of the new borehole. From drill core observations and modeling, the following conclusions can be drawn: (1) The lack of a shock metamorphic overprint of cored basement lithologies suggests that the drill core might not have reached the parautochthonous shocked crater floor but merely cored basement blocks that slumped off the rim of the original cavity into the crater during crater modification. (2) The sequence of polymict lithic breccia, suevite, and impact melt rock (1397-1551 m) must have been deposited prior to the arrival of the 950-m-thick resurge and avalanche-delivered beds and blocks within 5-7 min after impact. (3) This short period for transportation and deposition of impactites may suggest that the majority of the impactites of the Eyreville core never left the transient crater and was emplaced by ground surge. This is in accordance with observations of impact breccia fabrics. However, the uppermost part of the suevite section contains a pronounced component of airborne material. (4) Limited amounts of shock-deformed debris and melt fragments also occur throughout the Exmore beds. Shard-enriched intervals in the upper Exmore beds indicate that some material interpreted to be part of the hot ejecta plume was incorporated and dispersed into the upper resurge deposits. This suggests that collapse of the ejecta plume was contemporaneous with the major resurge event(s). Modeling indicates that the resurge flow should have been concluded some 20 min after impact; hence, this also likely marked the end of the major episode of deposition from the ejecta plume. © 2009 The Geological Society of America. 2009 English 00721077 10.1130/2009.2458(25) Special Paper of the Geological Society of America 458 Geological Society of America 571-585 Museum für Naturkunde-Leibniz Institute, Humboldt University Berlin, Invalidenstrasse 43, 10115 Berlin, Germany; Impact and Astromaterials Research Centre, Department of Earth Science and Engineering, Imperial College London, London, SW7 2AZ, United Kingdom; Lunar and Planetary Institute, 3600 Bay Area Boulevard, Houston, TX 77058, United States Boreholes; Buildings; Deposition; Drills; Infill drilling; Numerical models; Rocks; Seismology; Stratigraphy; Structural geology, Chesapeake Bay; Continental scientific drillings; Different stages; Drilling projects; Impact craters; Melt fragments; Petrographic analysis; U.S geological surveys, Core drilling, basement rock; breccia; computer simulation; crater; deposition; ejecta; emplacement; impactite; kinematics; lithology; mantle plume; numerical model; petrography; pyroclastic flow; research program; shock metamorphism, Chesapeake Bay; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-74949105414&doi=10.1130%2f2009.2458%2825%29&partnerID=40&md5=21bb78a881f3fc2407033566586ddc4d cited By 31 T. Kenkmann G.S. Collins A. Wittmann K. Wünnemann W.U. Reimold H.J. Melosh article Goderis2009145 The goal of this study is to identify the type of projectile responsible for the formation of the late Precambrian Gardnos impact structure in Norway. Fifteen impactite samples, predominantly impact breccias and suevites from the central and northeastern part of the structure, were analyzed for platinum group elements (PGE) and Au using nickel-sulfide fire assay combined with inductively coupled plasma mass spectrometry (ICP-MS). Major and trace elements were measured in the same samples using X-ray fluorescence (XRF). In addition, the concentrations of siderophile elements Ni, Cr, and Co were determined by ICP-MS after acid digestion. The samples collected at the contact between suevite and the sedimentary infill yielded the highest PGE concentrations (Ir = 1.926 ng/g, Ru = 3.494 ng/g, Pt = 4.716 ng/g, Rh = 0.766 ng/g, Pd = 2.842 ng/g for GC6). The CI-normalized PGE patterns are characterized by Ru and Rh enrichments suggesting a non-chondritic impactor. Concentration plots of the different PGE display an excellent correlation (R > 0.99), indicative of a single source for the PGE enrichment. The Ni/Cr ratio of the Gardnos impactor (2.56 ± 0.20) agrees with that of chondrites (2 to 7), whereas Ir is depleted relative to Ni in this projectile (Ni/Ir ratio of 92 000 ± 8000 compared to an average Ni/Ir ratio of 23 150 ± 4250 for chondrites). There is no clear indication of selective post-depositional remobilization of the characteristic highly siderophile elements. The Ni/Ir and Cr/Ir data combined with the non-chondritic PGE ratios probably indicate a differentiated projectile. Based on (1) the similarity of the inter-element ratios of the impactor with the iron phase of non-magmatic iron meteorites and (2) the presence of characteristics of both chondrites and iron meteorites (Ni/Cr and Ni/Ir ratios), an IA or IIIC non-magmatic iron meteorite is a very plausible impactor. © 2008 Elsevier B.V. All rights reserved. 2009 10.1016/j.chemgeo.2008.09.025 Chemical Geology 258 145-156 Department of Geology, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium; Department of Analytical Chemistry, Ghent University, Krijgslaan 281, -S12, B-9000 Ghent, Belgium; Natural History Museum, University of Oslo, N-0316 Oslo, Norway; Department of Geosciences, University of Oslo, N-0316 Oslo, Norway; Department of Mineralogy, Natural History Museum, Berlin, D-10099 Berlin, Germany; GeoForschungsZentrum Potsdam, D-14473 Potsdam, Germany 3-4 https://www.scopus.com/inward/record.uri?eid=2-s2.0-58149234108&doi=10.1016%2fj.chemgeo.2008.09.025&partnerID=40&md5=b9ac2bedec093f5f7912a419c6f27722 cited By 15 S. Goderis E. Kalleson R. Tagle H. Dypvik R.-T. Schmitt J. Erzinger P. Claeys article Riedel2009 We combine acoustic impedance inversion of 3D seismic data, log-to-seismic correlation, and seismic attribute analyses to delineate gas-hydrate zones at the Mallik site, Mackenzie Delta, Northwest Territories, Canada. Well-log data define three distinct hydrate zones over a depth range of 890-1100 m. Synthetic seismic modeling indicates the base of the two deeper hydrate zones are prominent reflectors. The uppermost gas-hydrate zone correlates to seismic data with a lower degree of confidence. The extent and geometry of the two lower hydrate zones suggest that local geology plays a significant role in the lateral and vertical distribution of gas hydrate at Mallik. The reliability of the hydrate concentrations calculated from the inverted impedances isqualified by the match between original and synthetic seismic data to produce confidence maps for the two lower gas-hydrate-bearing intervals. A total in-place volume estimate of solid gas hydrate for an area of 1.44 km2 around well 5L-38 yields a value of approximately 45 × 106m3 (equivalently, 6.6 × 109m3 of gas). We further qualify our mapping of gas hydrates by some amount of continuous resource, defined as lateral continuity measured by seismic attribute similarity and sand-dominated rock. Using these attributes, the continuous amount of hydrate at Mallik is about half the in-place volume (i.e., 25 × 106 m3). Elsewhere within the 3D seismic cube, the seismic impedance inversion yields evidence of potential gas-hydrate deposits near wells A-06 and P-59 at levels near the predicted base of the hydrate stability zone. © 2009 Society of Exploration Geophysicists. All rights reserved. 2009 English 00168033 10.1190/1.3159612 GEOPHYSICS 74 Society of Exploration Geophysicists B125-B137 McGill University, Department of Earth and Planetary Sciences, Montreal, QC, Canada; Geological Survey of Canada, Ottawa, ON, Canada; Geological Survey of Canada, Calgary, AB, Canada; Geological Survey of Canada, Sidney, BC, Canada 5 Acoustic impedance; Gases; Geophysical prospecting; Hydration; Seismic response; Seismic waves; Well logging, Acoustic impedance inversion; Degree of confidence; Hydrate concentration; Hydrate stabilities; Seismic attribute analysis; Seismic attributes; Seismic reflections; Vertical distributions, Gas hydrates, acoustic data; conference proceeding; confidence interval; gas field; gas hydrate; gas well; hydrocarbon resource; seismic data; seismic reflection; spatial distribution; three-dimensional modeling; well logging, Canada; Mackenzie Delta; North America; Northwest Territories https://www.scopus.com/inward/record.uri?eid=2-s2.0-71049118147&doi=10.1190%2f1.3159612&partnerID=40&md5=13d0893d90bc5dfde3ec36ea7d56004f cited By 43 M. Riedel G. Bellefleur S. Mair T.A. Brent S.R. Dallimore article McGarr20092815 For one week during September 2007, we deployed a temporary network of field recorders and accelerometers at four sites within two deep, seismically active mines. The ground-motion data, recorded at 200 samples/sec, are well suited to determining source and ground-motion parameters for the mining-induced earthquakes within and adjacent to our network. Four earthquakes with magnitudes close to 2 were recorded with high signal/noise at all four sites. Analysis of seismic moments and peak velocities, in conjunction with the results of laboratory stick-slip friction experiments, were used to estimate source processes that are key to understanding source physics and to assessing underground seismic hazard. The maximum displacements on the rupture surfaces can be estimated from the parameter Rv, where v is the peak ground velocity at a given recording site, and R is the hypocentral distance. For each earthquake, the maximum slip and seismic moment can be combined with results from laboratory friction experiments to estimate the maximum slip rate within the rupture zone. Analysis of the four M 2 earthquakes recorded during our deployment and one of special interest recorded by the in-mine seismic network in 2004 revealed maximum slips ranging from 4 to 27 mm and maximum slip rates from 1.1 to 6:3 m=sec. Applying the same analyses to an M 2.1 earthquake within a cluster of repeating earthquakes near the San Andreas Fault Observatory at Depth site, California, yielded similar results for maximum slip and slip rate, 14 mm and 4:0 m=sec. 2009 English 00371106 10.1785/0120080336 Bulletin of the Seismological Society of America 99 2815-2824 U.S. Geological Survey, MS 977 345 Middlefield Rd. Menlo Park, California 94025, United States; Council for Scientific and Industrial Research Natural Resources and Environmental Unit, P.O. Box 91230, Auckland Park 2006, South Africa 5 Broadband records; California; Deep gold mines; Ground motion parameters; Ground-motion; Hypocentral distance; Maximum displacement; Maximum slip; Peak ground velocity; Peak velocities; Repeating earthquake; Rupture surface; Rupture zone; San Andreas Fault; Seismic hazards; Seismic moment; Seismic networks; Slip rates; Source process; Stick-slip friction; Temporary networks, Experiments; Friction; Gold mines; Mines; Mining; Parameter estimation; Risk assessment; Slip forming; Tectonics, Earthquakes, earthquake catalogue; earthquake hypocenter; earthquake magnitude; gold mine; ground motion; mining-induced seismicity; seismic hazard; seismic moment; slip rate, California; North America; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-70349873690&doi=10.1785%2f0120080336&partnerID=40&md5=eadc13c48dee1062809d2dd7a84c75f7 cited By 16 A. McGarr M. Boettcher J.B. Fletcher R. Sell M.J.S. Johnston R. Durrheim S. Spottiswoode A. Milev conference Reshetnikov20093266 We have developed a passive seismic imaging approach which consists of two steps. Firstly, the hypocenter of the microseismic event is precisely located. Secondly, this event is treated as a "pseudo-active" seismic source and we process the reflections within the recorded wavefield using a directional migration algorithm in order to construct a high-resolution image in the close vicinity of the located hypo-center. In this paper we describe this approach and demonstrate the application to several microseismic events recorded by a borehole array in the SAFOD (San-Andreas-Fault-Observatory-at-Depth) main hole. The results are high-resolution images of different fault branches related to the San-Andreas-Fault (SAF) system in the close vicinity of the borehole. The comparison of these findings with existing surface seismic reflection images as well as additional borehole information demonstrate some interesting features. In summary our results allow a spatial characterization of the complex internal structure of the SAF and can certainly be helpful for other studies which rely on this knowledge. Copyright 2009, European Association of Geoscientists and Engineers. 2009 English 9781615672363 10523812 10.3997/2214-4609.201400525 71st European Association of Geoscientists and Engineers Conference and Exhibition 2009: Balancing Global Resources. Incorporating SPE EUROPEC 2009 5 Society of Petroleum Engineers 3266-3270 Free University Berlin, Germany 1 Boreholes; Strike-slip faults, Directional migration; High resolution image; Internal structure; Microseismic events; San Andreas fault; Seismic imaging; Seismic reflections; Spatial characterization, Seismology https://www.scopus.com/inward/record.uri?eid=2-s2.0-77049122785&doi=10.3997%2f2214-4609.201400525&partnerID=40&md5=0d7180bcbd1a2448f4155bbbf7c0905f cited By 0 A. Reshetnikov S. Buske S. Shapiro article Otsuki200913 The seismic slip behavior during the 1999 Chi-Chi, Taiwan, earthquake (Mw 7.6) was contrastive between the northern and southern segments of the activated Chelungpu fault; large, fast and smooth slips with large stress drop in the north, while smaller, slower and irregular slips with smaller stress drop in the south. We analyzed the pseudotachylyte samples recovered from 1194 m, 1243 m and 1314 m depths of Hole-B of Taiwan Chelungpu fault Drilling Project (TCDP) to reveal the spatial difference in friction mechanism. All pseudotachylyte layers are thin (0.7-2.8 cm), the volume fraction of protoliths is very large (more than 63%), and the estimated temperature distribution is very heterogeneous from ca. 750-1750 °C. These observations suggest that these pseudotachylyte melts were in the partial melting regime of Montgomery [Montgomery, R.S., 1976. Friction and wear at high sliding speeds. Wear 36, 275-298] where friction coefficient is abnormally large. Similar pseudotachylyte was found already in the core sample from 175 m depth of the Nanto borehole penetrating the southern fault. Since both pseudotachylyte samples from the two boreholes are older than the 1999 Chi-Chi event and have been uplifted from depths farther down-dip of their current locations, it is likely that recent seismic ruptures also would have encountered these mechanical barriers of viscous melt patches at deeper parts in the north than in the south. Elastohydrodynamic lubrication of clayey gouge worked effectively at the shallower parts of the northern segment, however there is no evidence that it played an important role in the south. These differences are the plausible causes of the contrastive local slip behaviors during the Chi-Chi earthquake. © 2008 Elsevier B.V. All rights reserved. 2009 English 00401951 10.1016/j.tecto.2009.01.008 Tectonophysics 469 13-24 Department of Geology, Graduate School of Science, Tohoku University, Sendai, Japan; Department of Earth and Space Science, Graduate School of Science, Osaka University, Toyonaka, Japan; Marine Works Japan, Nankoku, Japan; Kochi Institute for Core Sample Research, Japan Agency for Marine-Earth Science and Technology, Nankoku, Japan; Department of Geoscience, National Taiwan University, Taipei, Taiwan 1-4 Chelungpu fault; Chi-Chi earthquake; Partial melting; Pseudotachylyte; Seismic slip, Boreholes; Drops; Elastohydrodynamic lubrication; Friction; Melting; Tribology, Earthquakes, active fault; Chi-Chi earthquake 1999; earthquake magnitude; earthquake rupture; fault gouge; fault slip; focal mechanism; partial melting; pseudotachylite; uplift https://www.scopus.com/inward/record.uri?eid=2-s2.0-63049105877&doi=10.1016%2fj.tecto.2009.01.008&partnerID=40&md5=0c3c2d3b8a5f902fbf447f4d5f854729 cited By 21 K. Otsuki T. Hirono M. Omori M. Sakaguchi W. Tanigawa W. Lin W. Soh S.-S. Rong article Görgün2009507 We investigate spatial clustering of 2414 aftershocks along the Izmit Mw = 7.4 August 17, 1999 earthquake rupture zone. 25 days prior to the Düzce earthquake Mw = 7.2 (November 12, 1999), we analyze two spatial clusters, namely Sakarya (SC) and Karadere-Düzce (KDC). We determine the earthquake frequency-magnitude distribution (b-value) for both clusters. We find two high b-value zones in SC and one high b-value zone in KDC which are in agreement with large coseismic surface displacements along the Izmit rupture. The b-values are significantly lower at the eastern end of the Izmit rupture where the Düzce mainshock occurred. These low b-values at depth are correlated with low postseismic slip rate and positive Coloumb stress change along KDC. Since low b-values are hypothesized with high stress levels, we propose that at the depth of the Düzce hypocenter (12.5 km), earthquakes are triggered at higher stresses compared to shallower crustal earthquake. The decrease in b-value from the Karadere segment towards the Düzce Basin supports this low b-value high stress hypothesis at the eastern end of the Izmit rupture. Consequently, we detect three asperity regions which are correlated with high b-value zones along the Izmit rupture. According to aftershock distribution the half of the Düzce fault segment was active before the 12 November 1999 Düzce mainshock. This part is correlated with low b-values which mean high stress concentration in the Düzce Basin. This high density aftershock activity presumably helped to trigger the Düzce event (Mw = 7.2) after the Izmit Mw 7.4 mainshock. © 2009 Elsevier B.V. All rights reserved. 2009 English 00401951 10.1016/j.tecto.2009.04.027 Tectonophysics 474 507-515 Helmholtz Centre Potsdam GFZ, German Research Centre for Geosciences, Telegrafenberg, 14473 Potsdam, Germany 3-4 Aftershock distributions; B value; Crustal earthquakes; Earthquake frequency; Earthquake rupture; Fault asperities; Gutenberg-Richter law; High density; High stress; High stress concentration; Izmit earthquake; Mainshock; North Anatolian Fault Zone; Postseismic slip; Spatial cluster; Spatial clustering; Stress changes; Surface displacement, Earthquake effects; Stress concentration, Laws and legislation, aftershock; coseismic process; displacement; earthquake magnitude; earthquake rupture; earthquake trigger; fault zone; Kocaeli earthquake 1999; low velocity zone; North Anatolian Fault; postseismic process; slip rate; stress change, Duzce; Eurasia; Turkey https://www.scopus.com/inward/record.uri?eid=2-s2.0-69449085751&doi=10.1016%2fj.tecto.2009.04.027&partnerID=40&md5=c3d6f5d8ec9dbe8eaf6875a3f9de86f3 cited By 27 E. Görgün A. Zang M. Bohnhoff C. Milkereit G. Dresen article yuanliang2009anti 2009 石油钻采工艺 31 石油钻采工艺 53-56 4 LIU Yuanliang Wu Xiaoming ZHU Yongyi LI Xiaofen article Springer2009206 The San Andreas Fault Observatory at Depth (SAFOD) drill hole encountered indurated, high-seismic-velocity arkosic sedimentary rocks west of the active trace of the San Andreas fault in central California. The arkosic rocks are juxtaposed against granitic rocks of the Salinian block to the southwest and against fine-grained Great Valley Group and Jurassic Franciscan rocks to the northeast. We identify three distinct lithologic units using cuttings, core petrography, electrical resistivity image logs, zircon fission-track analyses, and borehole-based geophysical logs. The upper arkose occurs from 1920 to 2530 m measured depth (mmd) in the borehole and is composed of five structural blocks defined by bedding orientations, wireline log character, physical properties, and lithologic characteristics. A clay-rich zone between 2530 and 2680 mmd is characterized by low V p and an enlarged borehole. The lower arkose lies between 2680 and 3150 mmd. Fission-track detrital zircon cooling ages are between 64 and 70 Ma, appear to belong to a single population, and indicate a latest Cretaceous to Paleogene maximum depositional age. We interpret these Paleocene-Eocene strata to have been deposited in a proximal submarine fan setting shed from a Salinian source block, and they correlate with units to the southeast, along the western and southern edge of the San Joaquin Basin, and with arkosic conglomerates to the northwest. The arkosic section constitutes a deformed fault-bounded block between the modern strand of the San Andreas fault to the northeast and the Buzzard Canyon fault to the southwest. Significant amounts of slip appear to have been accommodated on both strands of the fault at this latitude. © 2009 Geological Society of America. 2009 English 19418264 10.1130/L13.1 Lithosphere 1 Geological Society of America 206-226 Department of Geology, Utah State University, Logan, UT 84322-4505, United States; Department of Geology, Union College, Schenectady, NY 12308-3107, United States; Earth and Atmospheric Sciences, Saint Louis University, 3507 Laclede Avenue, Saint Louis, MO 63103, United States; Chevron International Exploration and Production, 1500 Louisiana Street, Houston, TX 77002, United States 4 Boreholes; Fission reactions; Observatories; Silicate minerals; Strike-slip faults; Well logging; Zircon, Bedding orientations; Detrital zircon; Geophysical logs; Measured depths; San Andreas fault; Seismic velocities; Submarine fans; Zircon fission tracks, Sedimentary rocks, borehole; electrical resistivity; fission track dating; petrography; San Andreas Fault; sedimentary rock; seismic velocity, California; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-85011533833&doi=10.1130%2fL13.1&partnerID=40&md5=f606ec44cdc55f783f4e53645cd12d26 cited By 18 S.D. Springer J.P. Evans J.I. Garver D. Kirschner S.U. Janecke article Powars2009209 The U.S. Geological Survey (USGS) acquired two 1.4-km-long, high-resolution (̃5 m vertical resolution) seismic-reflection lines in 2006 that cross near the International Continental Scientifi c Drilling Program (ICDP)-USGS Eyreville deep drilling site located above the late Eocene Chesapeake Bay impact structure in Virginia, USA. Five-meter spacing of seismic sources and geophones produced high-resolution images of the subsurface adjacent to the 1766-m-depth Eyreville core holes. Analysis of these lines, in the context of the core hole stratigraphy, shows that moderateamplitude, discontinuous, dipping reflections below ̃527 m correlate with a variety of Chesapeake Bay impact structure sediment and rock breccias recovered in the cores. High-amplitude, continuous, subhorizontal reflections above ̃527 m depth correlate with the uppermost part of the Chesapeake Bay impact structure crater-fi ll sediments and postimpact Eocene to Pleistocene sediments. Refl ections with ̃20-30 m of relief in the uppermost part of the crater-fi ll and lowermost part of the postimpact section suggest differential compaction of the crater-fi ll materials during early postimpact time. The top of the crater-fi ll section also shows ̃20 m of relief that appears to represent an original synimpact surface. Truncation surfaces, locally dipping reflections, and depth variations in reflection amplitudes generally correlate with the lithostratigraphic and sequence-stratigraphic units and contacts in the core. Seismic images show apparent postimpact paleochannels that include the fi rst possible Miocene paleochannels in the Mid-Atlantic Coastal Plain. Broad downwarping in the postimpact section unrelated to structures in the crater fi ll indicates postimpact sediment compaction. © 2009 The Geological Society of America. 2009 English 00721077 10.1130/2009.2458(11) Special Paper of the Geological Society of America 458 Geological Society of America 209-233 U.S. Geological Survey, 926A National Center, Reston, VA 20192, United States; U.S. Geological Survey, 345 Middlefi eld Road, MS 977, Menlo Park, CA 94025, United States C (programming language); Compaction; Infill drilling; Seismic waves; Seismology; Stratigraphy, Chesapeake bay impact structures; Differential compaction; High resolution image; High resolution seismic; Pleistocene sediments; Reflection amplitude; Seismic reflections; U.s. geological surveys, Sediments, deep drilling; impact structure; lithostratigraphy; seismic reflection; seismic tomography; sequence stratigraphy, Chesapeake Bay; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-74949087401&doi=10.1130%2f2009.2458%2811%29&partnerID=40&md5=742a863c80343f4958cab9323b62fef9 cited By 18 D.S. Powars R.D. Catchings M.R. Goldman G.S. Gohn J.W. Horton Jr. L.E. Edwards M.J. Rymer G. Gandhok article Shanahan2009377 Although persistent drought in West Africa is well documented from the instrumental record and has been primarily attributed to changing Atlantic sea surface temperatures, little is known about the length, severity, and origin of drought before the 20th century. We combined geomorphic, isotopic, and geochemical evidence from the sediments of Lake Bosumtwi, Ghana, to reconstruct natural variability in the African monsoon over the past three millennia. We find that intervals of severe drought lasting for periods ranging from decades to centuries are characteristic of the monsoon and are linked to natural variations in Atlantic temperatures. Thus the severe drought of recent decades is not anomalous in the context of the past three millennia, indicating that the monsoon is capable of longer and more severe future droughts. Article 2009 English 10959203 10.1126/science.1166352 Science 324 377 – 380 5925 Africa; Ashanti; Atlantic Ocean; Ghana; Lake Bosumtwi; Sub-Saharan Africa; West Africa; rain; atmospheric forcing; drought; monsoon; reconstruction; sea surface temperature; twentieth century; Africa; article; Atlantic Ocean; controlled study; drought; environmental temperature; Ghana; hydrology; lake sediment; precipitation; priority journal; seasonal variation; spectroscopy https://www.scopus.com/inward/record.uri?eid=2-s2.0-65249152410&doi=10.1126%2fscience.1166352&partnerID=40&md5=5467b612752816295f744c8563fc4ab5 Cited by: 269 T.M. Shanahan J.T. Overpeck K.J. Anchukaitis J.W. Beck J.E. Cole D.L. Dettman J.A. Peck C.A. Scholz J.W. King article Keller200952 Biotic effects of the Chicxulub impact, the K-T event and sea level change upon planktic foraminifera were evaluated in a new core and outcrops along the Brazos River, Texas, about 1000 km from the Chicxulub impact crater on Yucatan, Mexico. Sediment deposition occurred in a middle neritic environment that shallowed to inner neritic depths near the end of the Maastrichtian. The sea level fall scoured submarine channels, which were infilled by a sandstone complex with reworked Chicxulub impact spherules and clasts with spherules near the base. The original Chicxulub impact ejecta layer was discovered 45-60 cm below the sandstone complex, and predates the K-T mass extinction by about 300,000 years. Results show that the Chicxulub impact caused no species extinctions or any other significant biotic effects. The subsequent sea level fall to inner neritic depth resulted in the disappearance of all larger (&gt; 150 μm) deeper dwelling species creating a pseudo-mass extinction and a survivor assemblage of small surface dwellers and low oxygen tolerant taxa. The K-T boundary and mass extinction was identified 40-80 cm above the sandstone complex where all but some heterohelicids, hedbergellids and the disaster opportunistic guembelitrids went extinct, coincident with the evolution of first Danian species and the global δ13C shift. These data reveal that sea level changes profoundly influenced marine assemblages in near shore environments, that the Chicxulub impact and K-T mass extinction are two separate and unrelated events, and that the biotic effects of this impact have been vastly overestimated. © 2008 Elsevier B.V. 2009 10.1016/j.palaeo.2008.09.007 Palaeogeography, Palaeoclimatology, Palaeoecology 271 52-68 Department of Geosciences, Princeton University, Princeton, NJ 08540, United States; Department of Geoloigcal and Environmental Sciences, Ben-Gurion University of the Negev, Beer Sheba, 84105, Israel; Institute for Mineralogy and Geochemistry, University of Karlsruhe, 76128 Karlsruhe, Germany; Geological and Paleontological Institute, Anthropole, CH-1015 Lausanne, Switzerland 1-2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-57849140528&doi=10.1016%2fj.palaeo.2008.09.007&partnerID=40&md5=eb3852c7d70afd1c4355304655fd2af7 cited By 42 G. Keller S. Abramovich Z. Berner T. Adatte article WANG2009288 The second and third member of the Qingshankou Formation recovered by CCSD-SK-Is borehole (China Cretaceous Continental Scientific Drilling-SongkeI-the south borehole) is 415.61 m long and 100% of cores recovery. The age of the member corresponds approximately to the Coniacian. The sequence and process of lithology-lithofacies and cyclic stratigraphy were revealed by a detailed core description. 12 rock types and 2 kinds of sedimentary subfacies including semi-deep lake and shallow lake were recognized from the drilling core of the second and third member of the Qingshankou Formation. 10 sedimentary microfacies are present, including dolomite, marl, limestone, oil shale, semi-deep lake turbidite, volcanic ash, seismite, semi-deep lake mudstone, shallow lake mudstone, and shallow lake turbidite microfacies. The second and third member of the Qingshankou Formation represents 422 meter-scale cycles (sixth-order cycle), 130 fifth-order cycles, 21 fourth-order cycles, and one third-order cycles. The special lithologies, such as mudstone, seismite, dolomite, volcanic ash, and so on are important to researches on source rocks and lacustrine event sediments. © 2009 China University of Geosciences (Beijing) and Peking University. Article 2009 English 18725791 10.1016/S1872-5791(08)60080-9 Dixue Qianyuan/ Earth Science Frontiers 16 288 – 313 College of Earth Sciences, Jilin University, Changchun, 130061, China; Institute of Exploration and Development, Daqing Oilfield Company Ltd., Daqing, 163712, China; School of Earth Sciences and Resources, China University of Geosciences (Beijing), Beijing, 100083, China; School of Engineering, China University of Geosciences (Beijing), Beijing, 100083, China 2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-71049135697&doi=10.1016%2fS1872-5791%2808%2960080-9&partnerID=40&md5=c32a51a1e66efa5f11f03134a6f5d5db Cited by: 29 Pujun Wang Youfeng Gao Rihui Cheng Guodong Wang Heyong WU Xiaoqiao Wan Gansheng Yang Zhongxing WANG article Wilke200925 Biologists have used a wide range of organisms to study the origin of taxa and their subsequent evolutionary change in space and time. One commonly used tool is the molecular clock approach, relating substitution rates of nucleotide or amino acid sequences to divergence times. The accuracy of the molecular clock, however, has long been subject to controversy, and numerous papers have addressed problems associated with estimating divergence times. Some workers pointed out a striking imbalance between sophisticated software algorithms used for molecular clock analyses on the one hand, and the poor data on the other hand. Moreover, there is often unease among workers relative to molecular clocks because of the controversy surrounding the approach, the complex mathematical background of many molecular clock tools, the still limited number of available, user-friendly software packages, the often confusing terminology of molecular clock approaches, and the general lack of reliable calibration points and/or external clock rates. The current review therefore briefly provides an overview of analytical strategies, covering approaches based on calibration points and/or bounds, approaches based on external clock rates, and approaches that attempt to estimate relative divergence times in the absence of information that can be used for estimating substitution rates. It also deals with major problems and pitfalls associated with data and analyses, including potential errors of calibration points and bounds, the performance of the gene(s) used, estimation of confidence limits, and misinterpretation of the results of clock analyses due to problems with sampling design. A substantial part of the review addresses the question of "universal" molecular clock rates and summarizes important biological and life history variables that account for deviations from rate constancy both between lineages and at different times within lineages. The usefulness of these factors is discussed within the framework of "trait-specific" molecular clock rates. One such clock rate is introduced here for the cytochrome c oxidase subunit I (COI) gene in small dioecious, tropical and subtropical Protostomia with a generation time of approximately one year. A flow chart is provided as a "simple fool's guide" to molecular clock analyses, together with a glossary of widely used terms in molecular clock approaches. Finally, step-by-step examples are provided for calculating divergence times in the caenogastropod subfamily Pyrgulinae based on both an internal calibration point and a "trait-specific" molecular clock rate, and it is demonstrated how a relative clock approach can be used for testing evolutionary hypotheses. Our review encourages a judicious use of molecular clock analyses in evolutionary studies of invertebrates by demonstrating their great potential on the one hand and (often-manageable) problems and pitfalls on the other hand. Conference paper 2009 English 07402783 10.4003/006.027.0203 American Malacological Bulletin 27 American Malacological Society 25 – 45 1-2 Caenogastropoda; Invertebrata; Protostomia https://www.scopus.com/inward/record.uri?eid=2-s2.0-69149111299&doi=10.4003%2f006.027.0203&partnerID=40&md5=9d2d19b55069e18253715595d1235c5c Cited by: 182 Thomas Wilke Roland Schultheiß Christian Albrecht article Liu2009805 Based on new evidence the Sulu orogen is divided from south-east to north-west into high-pressure (HP) crustal slice I and ultrahigh-pressure (UHP) crustal slices II and III. A combined set of mineral inclusions, cathodoluminescence images, U-Pb SHRIMP dating and in situ trace element and Lu-Hf isotope analyses was obtained on zircon from orthogneisses of the different slices. Zircon grains typically have three distinct domains that formed during crystallization of the magmatic protolith, HP or UHP metamorphism and late-amphibolite facies retrogression, respectively: (i) oscillatory zoned cores, with low-pressure (LP) mineral inclusions and Th/U > 0.38; (ii) high-luminescent mantles (Th/U < 0.10), with HP mineral inclusions of Qtz + Grt + Arg + Phe + Ap for slice I zircon and Coe + Grt + Phe + Kfs + Ap for both slices II and III zircon; (iii) low-luminescent rims, with LP mineral inclusions and Th/U < 0.08. Zircon U-Pb SHRIMP analyses of inherited cores point to protolith ages of 785-770 Ma in all seven orthogneisses. The ages recorded for UHP metamorphism and subsequent retrogression in slice II zircon (c. 228 and c. 215 Ma, respectively) are significantly older than those of slice III zircon (c. 218 and c. 202 Ma, respectively), while slice I zircon recorded even older ages for HP metamorphism and subsequent retrogression (c. 245 and c. 231 Ma, respectively). Moreover, Ar-Ar biotite ages from six paragneisses, interpreted as dating amphibolite facies retrogression, gradually decrease from HP slice I (c. 232 Ma) to UHP slice II (c. 215 Ma) and UHP slice III (c. 203 Ma). The combined data set suggests decreasing ages for HP or UHP metamorphism and late retrogression in the Sulu orogen from south-east to north-west. Thus, the HP-UHP units are interpreted to represent three crustal slices, which underwent different subduction and exhumation histories. Slice I was detached from the continental lithosphere at ∼55-65 km depth and subsequently exhumed while subduction of the underlying slice II continued to ∼100-120 km depth (UHP) before detachment and exhumation. Slice III experienced a similar geodynamic evolution as slice II, however, both UHP metamorphism and subsequent exhumation took place c. 10 Myr later. Magmatic zircon cores from two types of orthogneiss in UHP slices II and III show similar mid-Neoproterozoic crystallization ages, but have contrasting Hf isotope compositions (εHf(∼785) = -2.7 to +2.2 and -17.3 to -11.1, respectively), suggesting their formation from distinct crustal units (Mesoproterozoic and Paleoproterozoic to Archean, respectively) during the breakup of Rodinia. The UHP and the retrograde zircon domains are characterized by lower Th/U and 176Lu/177Hf but higher 176Hf/177Hf(t) than the Neoproterozoic igneous cores. The similarity between UHP and retrograde domains indicates that late retrogression did not significantly modify chemical and isotopic composition of the UHP metamorphic system. © 2009 Blackwell Publishing Ltd. Article 2009 English 15251314 10.1111/j.1525-1314.2009.00833.x Journal of Metamorphic Geology 27 805 – 825 9 Asia; China; Eurasia; Far East; Sulu Belt; amphibolite facies; cathodoluminescence; continental lithosphere; crystallization; exhumation; hafnium; isotopic analysis; isotopic composition; lead isotope; lutetium; orthogneiss; Proterozoic; rare earth element; SHRIMP dating; subduction; trace element; ultrahigh pressure metamorphism; uranium-lead dating; zircon https://www.scopus.com/inward/record.uri?eid=2-s2.0-70450179896&doi=10.1111%2fj.1525-1314.2009.00833.x&partnerID=40&md5=64863f0e0d86e10cb1186cd8878b46a1 Cited by: 63 F.L. Liu A. Gerdes H.M. Xue article Edwards200951 The Eyreville A and B cores, recovered from the "moat" of the Chesapeake Bay impact structure, provide a thick section of sediment-clast breccias and minor stratified sediments from 1095.74 to 443.90 m. This paper discusses the components of these breccias, presents a geologic column and descriptive lithologic framework for them, and formalizes the Exmore Formation. From 1095.74 to ̃867 m, the cores consist of nonmarine sediment boulders and sand (rare blocks up to 15.3 m intersected diameter). A sharp contact in both cores at ̃867 m marks the lowest clayey, silty, glauconitic quartz sand that constitutes the base of the Exmore Formation and its lower diamicton member. Here, material derived from the upper sediment target layers, as well as some impact ejecta, occurs. The block-dominated member of the Exmore Formation, from ̃855-618.23 m, consists of nonmarine sediment blocks and boulders (up to 45.5 m) that are juxtaposed complexly. Blocks of oxidized clay are an important component. Above 618.23 m, which is the base of the informal upper diamicton member of the Exmore Formation, the glauconitic matrix is a consistent component in diamicton layers between nonmarine sediment clasts that decrease in size upward in the section. Crystalline-rock clasts are not randomly distributed but rather form local concentrations. The upper part of the Exmore Formation consists of crudely fining-upward sandy packages capped by laminated silt and clay. The overlap interval of Eyreville A and B (940-̃760 m) allows recognition of local similarities and differences in the breccias. © 2009 The Geological Society of America. 2009 English 00721077 10.1130/2009.2458(03) Special Paper of the Geological Society of America 458 Geological Society of America 51-89 U.S. Geological Survey, 926A National Center, Reston, VA 20192, United States; University of Oslo, P.O. Box 1047, Blindern, N-0316 Oslo, Norway Crystalline rocks; Rocks, Chesapeake bay impact structures; Impact ejecta; Local similarity; Quartz sand; Randomly distributed, Sediments, breccia; diamicton; ejecta; impact structure; lithology; marine sediment, Chesapeake Bay; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-74949119592&doi=10.1130%2f2009.2458%2803%29&partnerID=40&md5=79bd3ed2abeca9c38e56153d8c7aa825 cited By 38 L.E. Edwards D.S. Powars G.S. Gohn H. Dypvik article Skála2009435 The International Continental Scientific Drilling Program (ICDP)-U.S. Geological Survey (USGS) Eyreville B core hole, drilled into the 35.5-Ma-old Chesapeake Bay impact crater, Virginia, has recovered postimpact sediments, crater-fill breccias, megablocks of the crystalline basement, and suevites with fresh glass shards. Bulk rock analyses of 2 glass shards, 21 crystalline target rocks, and microchemical analyses of 7 glass shards and 3 bediasites (tektites of the North American strewn field) were performed in order to contribute to the understanding of formation processes and to better constrain the precursor materials of these glasses as well as of the bediasites. Statistical treatment (hierarchical cluster analyses) yielded an assignment of the data for the crystalline basement samples into four groups; two of those (various schists, meta-graywackes, and gneisses) display characteristics similar to the impact glasses in the suevites and the bediasites. However, the suevitic glasses show a broad range in composition at the micrometer scale. These data show the frequent presence of schlieren, and in particular, enhanced TiO2 contents that require admixture of an "amphibolitic component" to the melt. Evidence for such a process is provided by the occurrence of relict, in-part thermally corroded grains of rutile and ilmenite, and by formation of Ti-rich tiny mineral aggregates in the glass. The three studied bediasites show only minor inter- and intrasample heterogeneity, and their chemical composition agrees well with previously published data. The new data for the bediasites are compatible with heating of the "tektite melt" to extreme temperatures, followed by quenching. © 2009 The Geological Society of America. 2009 English 00721077 10.1130/2009.2458(19) Special Paper of the Geological Society of America 458 Geological Society of America 435-445 Institute of Geology, Academy of Sciences of the Czech Republic, Rozvojová 269, CZ-16500 Praha 6, Czech Republic; Institut für Geowissenschaften, Friedrich-Schiller-Universität Jena, Burgweg 11, D-07749 Jena, Germany; Bayerisches Geoinstitut, Universität Bayreuth, D-95440 Bayreuth, Germany; Institut für Planetologie, Westfälische Wilhelms-Universität, Wilhelm-Klemm-Strasse 10, D-48149 Münster, Germany Boreholes; Buildings; Cluster analysis; Crystalline materials; Crystalline rocks; Glass; Hierarchical systems; Infill drilling; Oxide minerals; Titanium dioxide, Chesapeake bay impact structures; Continental scientific drillings; Crystalline target rocks; Display characteristics; Geochemical characteristic; Hierarchical cluster analysis; Microchemical analysis; U.s. geological surveys, Core drilling, breccia; chemical composition; crater; impact structure; marine sediment; sediment chemistry; suevite, Chesapeake Bay; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-74949093425&doi=10.1130%2f2009.2458%2819%29&partnerID=40&md5=7cac119be381fda26f000684562f09f1 cited By 3 R. Skála F. Langenhorst A. Deutsch article Ren20091553 Numerous geochemical studies have indicated that the Hawaiian mantle plume consists of several distinct components. However, their origin remains controversial, with a number of different interpretations having been proposed. We present new major element, trace element and high-precision Sr-Nd-Pb-He isotope data for a suite of fresh submarine lavas erupted by the Koolau, Kilauea and Loihi volcanoes, which are widely believed to have sampled three distinct Hawaiian plume components. The Sr and Nd isotope compositions of the Loihi lavas are similar to those of Kilauea lavas. However, our double-spike Pb isotopic data show that Loihi lavas have both Kilauea-like and Loihi-like compositions. This discovery implies that the Loihi source region contains a Kilauea-like ('Kea') mantle component. Our new data support the existence of three major types of intrinsic plume component: a Loihi component, an 'enriched' (Koolau) component and a 'depleted' (Kea) component. We propose that the Loihi component is a common component, forming the matrix in the Hawaiian mantle plume, and that the isotopic differences between the various shield lavas reflect different mixing proportions of the Loihi component and recycled oceanic crust components (EM-1-like and HIMU-like). The Koolau component contains a higher proportion of EM-1, whereas the Kea component contains a higher proportion of HIMU. EM-1- and HIMU-like recycled oceanic crust components are distributed on a fine scale throughout the peridotitic matrix within the Hawaiian plume. Both components are present in the sources beneath Kea- and Loa-trend volcanoes. We infer that the thermal structure and spatially distributed compositional heterogeneity of the plume are important in controlling the isotopic composition of lavas from a given Hawaiian volcano. © The Author 2009. Published by Oxford University Press. All rights reserved. 2009 English 00223530 10.1093/petrology/egp041 Journal of Petrology 50 1553-1573 Key Laboratory of Isotope Geochronology and Geochemistry, Guangzhou Institute of Geochemistry (GIG), Chinese Academy of Sciences (CAS), 511 Kehua Street, Wushan, Guangzhou 510640, China; Institute for Research on Earth Evolution (IFREE), JAPAN Agency for Marine-Earth Science and Technology (JAMSTEC), 2-5 Natsushima-Cho, Yokosuka, Kanagawa 237-0061, Japan 8 helium isotope; heterogeneity; igneous geochemistry; isotopic composition; lava; lead isotope; mantle chemistry; mantle plume; neodymium isotope; oceanic crust; partial melting; precision; shield; source rock; spatial distribution; strontium isotope, Hawaii [United States]; North America; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-68249147528&doi=10.1093%2fpetrology%2fegp041&partnerID=40&md5=0fd9e7166c344b5250d2a6004ee4d269 cited By 45 Z.-Y. Ren T. Hanyu T. Miyazaki Q. Chang H. Kawabata T. Takahashi Y. Hirahara A.R.L. Nichols Y. Tatsumi article FANGWei_181 2009 Earth Science Frontiers 16 Earth Science Frontiers 181-191 5 Key words: Songliao Basin; Well SK1; organic geochemistry; deposition environment https://www.earthsciencefrontiers.net.cn/EN/abstract/article_3664.shtml WANG Xue FANG Wei article Schmitt2009481 We investigated whole-rock chemical compositions of 318 samples of Exmore breccia (diamicton), impactite (suevite, impact melt rock, polymict lithic impact breccia), and crystalline basement-derived rocks from 444 to 1766 m depth in the International Continental Scientific Drilling Program (ICDP)-U.S. Geological Survey (USGS) Eyreville A and B drill cores (Chesapeake Bay impact structure, Virginia, USA). Here, we compare the average chemical compositions for the Exmore breccia (diamicton), the impactites and their subunits, sandstone, granite, granitic gneiss, and amphibolite of the lithic block section (1095.7-1397.2 m depth), cataclastic gneiss of the impact breccia section, and schist and pegmatite/granite of the basal crystalline section (1551.2-1766.3 m depth). The granite of the megablock (1097.7-1371.1 m depth) is of I-type and is seemingly related to a syncollisional setting. The amphibolite (1377.4-1387.5 m depth) of the lithic block section is of igneous origin and has a tholeiitic character. Based on chemical composition, the Exmore breccia (diamicton) can be subdivided into five units (444.9-450.7, 450.7-468, 468-518, 518-528, and 528-̃865 m depth). The units in the depth intervals of 450.7-468 and 518-528 m are enriched in TiO2, MgO, Sc, V, Cr, and Zn contents compared to the other Exmore breccia units. In some samples, especially at ̃451-455 m depth, the Exmore breccia contains significant amounts of P 2 O 5 . The Exmore breccia is recognized as a mixture of all sedimentary and crystalline target components, and, when compared to the impactites, it contains a significant amount of a SiO 2 -rich target component of sedimentary origin. The chemical composition of the impactites overlaps the compositional range for the Exmore breccia. The impactites generally display a negative correlation of SiO 2 and CaO, and a positive correlation of TiO 2 , Al 2 O 3 , Fe 2 O 3 , and MgO with depth. This is the result of an increasing basement schist component, and a decreasing sedimentary and/or granitic component with depth. Suevite units S2 and S3 display distinct enrichment of Na 2 O by a factor of ̃2 compared to all other impactite units, which is interpreted to reflect a higher granitic component in these units. © 2009 The Geological Society of America. 2009 10.1130/2009.2458(22) Special Paper of the Geological Society of America 458 481-541 Museum für Naturkunde-Leibniz Institute, Humboldt University Berlin, Invalidenstrasse 43, 10115 Berlin, Germany; Department of Lithospheric Research, Center for Earth Sciences, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria; Impact Cratering Research Group, School of Geosciences, University of the Witwatersrand, Private Bag 3, PO Wits, Johannesburg, 2050, South Africa; Lunar and Planetary Institute, 3600 Bay Area Boulevard, Houston, TX 77058, United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-74949119586&doi=10.1130%2f2009.2458%2822%29&partnerID=40&md5=4d98fae5966f516484085e0f3568d599 cited By 18 R.T. Schmitt K. Bartosova W.U. Reimold D. Mader A. Wittmann C. Koeberl R.L. Gibson article Schmitt2009481 We investigated whole-rock chemical compositions of 318 samples of Exmore breccia (diamicton), impactite (suevite, impact melt rock, polymict lithic impact breccia), and crystalline basement-derived rocks from 444 to 1766 m depth in the International Continental Scientific Drilling Program (ICDP)-U.S. Geological Survey (USGS) Eyreville A and B drill cores (Chesapeake Bay impact structure, Virginia, USA). Here, we compare the average chemical compositions for the Exmore breccia (diamicton), the impactites and their subunits, sandstone, granite, granitic gneiss, and amphibolite of the lithic block section (1095.7-1397.2 m depth), cataclastic gneiss of the impact breccia section, and schist and pegmatite/granite of the basal crystalline section (1551.2-1766.3 m depth). The granite of the megablock (1097.7-1371.1 m depth) is of I-type and is seemingly related to a syncollisional setting. The amphibolite (1377.4-1387.5 m depth) of the lithic block section is of igneous origin and has a tholeiitic character. Based on chemical composition, the Exmore breccia (diamicton) can be subdivided into five units (444.9-450.7, 450.7-468, 468-518, 518-528, and 528-̃865 m depth). The units in the depth intervals of 450.7-468 and 518-528 m are enriched in TiO2, MgO, Sc, V, Cr, and Zn contents compared to the other Exmore breccia units. In some samples, especially at ̃451-455 m depth, the Exmore breccia contains significant amounts of P 2 O 5 . The Exmore breccia is recognized as a mixture of all sedimentary and crystalline target components, and, when compared to the impactites, it contains a significant amount of a SiO 2 -rich target component of sedimentary origin. The chemical composition of the impactites overlaps the compositional range for the Exmore breccia. The impactites generally display a negative correlation of SiO 2 and CaO, and a positive correlation of TiO 2 , Al 2 O 3 , Fe 2 O 3 , and MgO with depth. This is the result of an increasing basement schist component, and a decreasing sedimentary and/or granitic component with depth. Suevite units S2 and S3 display distinct enrichment of Na 2 O by a factor of ̃2 compared to all other impactite units, which is interpreted to reflect a higher granitic component in these units. © 2009 The Geological Society of America. 2009 English 00721077 10.1130/2009.2458(22) Special Paper of the Geological Society of America 458 Geological Society of America 481-541 Museum für Naturkunde-Leibniz Institute, Humboldt University Berlin, Invalidenstrasse 43, 10115 Berlin, Germany; Department of Lithospheric Research, Center for Earth Sciences, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria; Impact Cratering Research Group, School of Geosciences, University of the Witwatersrand, Private Bag 3, PO Wits, Johannesburg, 2050, South Africa; Lunar and Planetary Institute, 3600 Bay Area Boulevard, Houston, TX 77058, United States Alumina; Aluminum oxide; Buildings; Crystalline materials; Crystalline rocks; Drills; Granite; Hematite; Infill drilling; Magnesia; Sedimentology; Silica; Sodium compounds; Structure (composition); Titanium dioxide, Chemical compositions; Chesapeake bay impact structures; Continental scientific drillings; Crystalline basement; Crystalline targets; Negative correlation; Positive correlations; U.s. geological surveys, Core drilling, amphibolite; basement rock; breccia; chemical composition; coastal sediment; crystalline rock; enrichment; gneiss; I-type rock; impact structure; impactite; lithology; research program; sandstone; schist; sediment chemistry, Chesapeake Bay; United States; Virginia https://www.scopus.com/inward/record.uri?eid=2-s2.0-74949119586&doi=10.1130%2f2009.2458%2822%29&partnerID=40&md5=4d98fae5966f516484085e0f3568d599 cited By 18 R.T. Schmitt K. Bartosova W.U. Reimold D. Mader A. Wittmann C. Koeberl R.L. Gibson article Bartosova2009397 The Chesapeake Bay impact structure, which is 85 km in diameter and 35.5 Ma old, was drilled and cored in a joint International Continental Scientific Drilling Program (ICDP) and U.S. Geological Survey (USGS) drilling project at Eyreville Farm, Virginia, U.S.A. In the Eyreville drill core, 154 m of impact breccia were recovered from the depth interval 1397-1551 m. Major- and trace-element concentrations were determined in 75 polymict impactite samples, 10 samples of cataclastic gneiss blocks, and 24 clasts from impactites. The chemical composition of the polymict impactites does not vary much in the upper part of the section (above ̃1450 m), whereas in the lower part, larger differences occur. Polymict impactites show a decrease of SiO 2 content, and slight increases of TiO 2 , Al 2 O 3 , and Fe 2 O 3 abundances, with depth. This is in agreement with an increase of the schist/gneiss component with depth. Concentrations of siderophile elements (Co, Ni) are lower in the polymict impactites than in the basement-derived schists and do not indicate the presence of an extraterrestrial component. The fi ve petrographically determined types of melt particles, i.e., clear glass, altered melt, recrystallized silica melt, melt with microlites, and dark-brown melt, have distinct chemical compositions. Mixing calculations of the proportions of rocks involved in the formation of various polymict impactites and melt particles were carried out using the Harmonic least-squares MiXing (HMX) calculation program. The calculations suggest that the metamorphic basement rocks (i.e., gneiss and schist) constitute the main component of the polymict impactites, together with significant sedimentary and possible minor pegmatite/granite and amphibolite components. The sedimentary component is derived mostly from a sediment characterized by a composition similar to that of the Cretaceous Potomac Formation. Compositions of the melt particles were modeled as mixtures of target rocks or major rock-forming minerals. However, the results of the mixing calculations for the melt particles are not satisfactory, and the composition of the particles could have been modified by hydrothermal alteration. Carbon isotope ratios were determined for 18 samples. The results imply a hydrothermal origin for the carbonate veins from the basement-derived core section; carbon-rich sedimentary clasts from the Exmore breccia and suevite have a δ 13 C range typical for organic matter in sediments. © 2009 The Geological Society of America. 2009 English 00721077 10.1130/2009.2458(18) Special Paper of the Geological Society of America 458 Geological Society of America 397-433 Department of Lithospheric Research, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria; Museum für Naturkunde-Leibniz Institute, Humboldt University Berlin, Invalidenstrasse 43, 10115 Berlin, Germany; Department of Earth Science, University of Western Ontario, 1151 Richmond Street, London, ON N6A 5B7, Canada; Natural History Museum, Burgring 7, A-1010 Vienna, Austria Alumina; Aluminum oxide; Buildings; Carbon; Clay alteration; Drills; Hematite; Infill drilling; Metamorphic rocks; Mixer circuits; Mixing; Sedimentary rocks; Sedimentology; Silica; Structure (composition); Titanium dioxide; Trace elements, Chesapeake bay impact structures; Continental scientific drillings; Extraterrestrial components; Hydrothermal alterations; Major and trace elements; Metamorphic basements; Rock-forming minerals; U.s. geological surveys, Core drilling, breccia; chemical composition; drilling; geochemistry; impact structure; impactite; marine sediment; trace element, Chesapeake Bay; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-74949095526&doi=10.1130%2f2009.2458%2818%29&partnerID=40&md5=a301fa5740f3c47995c05de4253e7778 cited By 13 K. Bartosova D. Mader R.T. Schmitt L. Ferrière C. Koeberl W.U. Reimold F. Brandstätter article Bartosova2009397 The Chesapeake Bay impact structure, which is 85 km in diameter and 35.5 Ma old, was drilled and cored in a joint International Continental Scientific Drilling Program (ICDP) and U.S. Geological Survey (USGS) drilling project at Eyreville Farm, Virginia, U.S.A. In the Eyreville drill core, 154 m of impact breccia were recovered from the depth interval 1397-1551 m. Major- and trace-element concentrations were determined in 75 polymict impactite samples, 10 samples of cataclastic gneiss blocks, and 24 clasts from impactites. The chemical composition of the polymict impactites does not vary much in the upper part of the section (above ̃1450 m), whereas in the lower part, larger differences occur. Polymict impactites show a decrease of SiO 2 content, and slight increases of TiO 2 , Al 2 O 3 , and Fe 2 O 3 abundances, with depth. This is in agreement with an increase of the schist/gneiss component with depth. Concentrations of siderophile elements (Co, Ni) are lower in the polymict impactites than in the basement-derived schists and do not indicate the presence of an extraterrestrial component. The fi ve petrographically determined types of melt particles, i.e., clear glass, altered melt, recrystallized silica melt, melt with microlites, and dark-brown melt, have distinct chemical compositions. Mixing calculations of the proportions of rocks involved in the formation of various polymict impactites and melt particles were carried out using the Harmonic least-squares MiXing (HMX) calculation program. The calculations suggest that the metamorphic basement rocks (i.e., gneiss and schist) constitute the main component of the polymict impactites, together with significant sedimentary and possible minor pegmatite/granite and amphibolite components. The sedimentary component is derived mostly from a sediment characterized by a composition similar to that of the Cretaceous Potomac Formation. Compositions of the melt particles were modeled as mixtures of target rocks or major rock-forming minerals. However, the results of the mixing calculations for the melt particles are not satisfactory, and the composition of the particles could have been modified by hydrothermal alteration. Carbon isotope ratios were determined for 18 samples. The results imply a hydrothermal origin for the carbonate veins from the basement-derived core section; carbon-rich sedimentary clasts from the Exmore breccia and suevite have a δ 13 C range typical for organic matter in sediments. © 2009 The Geological Society of America. 2009 10.1130/2009.2458(18) Special Paper of the Geological Society of America 458 397-433 Department of Lithospheric Research, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria; Museum für Naturkunde-Leibniz Institute, Humboldt University Berlin, Invalidenstrasse 43, 10115 Berlin, Germany; Department of Earth Science, University of Western Ontario, 1151 Richmond Street, London, ON N6A 5B7, Canada; Natural History Museum, Burgring 7, A-1010 Vienna, Austria https://www.scopus.com/inward/record.uri?eid=2-s2.0-74949095526&doi=10.1130%2f2009.2458%2818%29&partnerID=40&md5=a301fa5740f3c47995c05de4253e7778 cited By 13 K. Bartosova D. Mader R.T. Schmitt L. Ferrière C. Koeberl W.U. Reimold F. Brandstätter article Edwards200991 A 443.9-m-thick, virtually undisturbed section of postimpact deposits in the Chesapeake Bay impact structure was recovered in the Eyreville A and C cores, Northampton County, Virginia, within the "moat" of the structure's central crater. Recovered sediments are mainly fine-grained marine siliciclastics, with the exception of Pleistocene sand, clay, and gravel. The lowest postimpact unit is the upper Eocene Chickahominy Formation (443.9-350.1 m). At 93.8 m, this is the maximum thickness yet recovered for deposits that represent the return to "normal marine" sedimentation. The Drummonds Corner beds (informal) and the Old Church Formation are thin Oligocene units present between 350.1 and 344.7 m. Above the Oligocene, there is a more typical Virginia coastal plain succession. The Calvert Formation (344.7-225.4 m) includes a thin lower Miocene part overlain by a much thicker middle Miocene part. From 225.4 to 206.0 m, sediments of the middle Miocene Choptank Formation, rarely reported in the Virginia coastal plain, are present. The thick upper Miocene St. Marys and Eastover Formations (206.0-57.8 m) appear to represent a more complete succession than in the type localities. Correlation with the nearby Kiptopeke core indicates that two Pliocene units are present: Yorktown (57.8-32.2 m) and Chowan River Formations (32.2-18.3 m). Sediments at the top of the section represent an upper Pleistocene channel-fill and are assigned to the Butlers Bluff and Occohannock Members of the Nassawadox Formation (18.3-0.6 m). © 2009 The Geological Society of America. 2009 English 00721077 10.1130/2009.2458(04) Special Paper of the Geological Society of America 458 Geological Society of America 91-114 U.S. Geological Survey, 926A National Center, Reston, VA 20192, United States; Department of Earth and Planetary Sciences, Rutgers University, Piscataway, NJ 08854, United States; Delaware Geological Survey, University of Delaware, DGS Building, 257 Academy Street, Newark, DE 19716, United States; Chevron Energy Technology Company, 1500 Louisiana St., Houston, TX 77002, United States; Laboratory of Solid Earth Geophysics, Department of Physics, University of Helsinki, P.O. Box 64, Helsinki, 00014, Finland Deposits; Recovery, Channel fills; Chesapeake bay impact structures; Coastal plain; Lower Miocene; Maximum thickness; Middle Miocene; Pleistocene sands; Siliciclastics, Sediments, crater; Eocene; fine grained sediment; impact structure; Oligocene; Pleistocene; sedimentation, Chesapeake Bay; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-74949094807&doi=10.1130%2f2009.2458%2804%29&partnerID=40&md5=4bba52c903cbc7aaf1af7c59f1cf17be cited By 28 L.E. Edwards D.S. Powars J.V. Browning P.P. McLaughlin Jr. K.G. Miller J.M. Self-Trail A.A. Kulpecz T. Elbra article Tanikawa2009 We carried out low- and high-velocity friction tests on fault rock samples from shallow boreholes on the Taiwan Chelungpu fault and measured their fluid transport properties under high pressure, with the objective of explaining the different seismic behaviors in the northern and southern sections of the fault during the 1999 Chi-Chi earthquake. Our results of low-velocity friction tests demonstrate that fault gouge from the southern section of the fault exhibits velocity-weakening frictional behavior, whereas gouge from the northern section exhibits velocity-strengthening friction. Friction in the northern gouge decreased strongly with increasing wetness, whereas friction in southern gouge samples was not affected by wetness. A rapid reduction of friction was observed immediately after the onset of slip in high-velocity friction tests. The results of high-velocity friction tests were similar for all fault gouge samples tested, although permeability in the northern fault zone was lower than that in the south. Numerical modeling indicated that thermal pressurization in the northern fault zone promoted stress reduction and fault instability during slip, whereas it did not in the south. This contrasting seismic behavior between north and south is caused mainly by differences in fluid transport properties of the slip zones. More efficient thermal pressurization in the north explains the large slip displacement there. The results of our low-velocity friction tests are consistent with nucleation of the Chi-Chi earthquake in the south and propagation of the rupture from south to north. Copyright 2009 by the American Geophysical Union. 2009 English 21699313 10.1029/2008JB005750 Journal of Geophysical Research: Solid Earth 114 Blackwell Publishing Ltd Kochi Institute for Core Sample Research, Japan Agency for Marine-Earth Science and Technology, 200 Monobe-otsu, Nankoku, Kochi 783-8502, Japan; Department of Earth and Planetary Systems Science, Graduate School of Science, Hiroshima University, Higashi-Hiroshima 739-8526, Japan 1 borehole; Chi-Chi earthquake 1999; earthquake rupture; fault zone; fluid flow; friction; high pressure; numerical model; seismicity; slip, Asia; Chelungpu Fault Zone; Eurasia; Far East; Taiwan https://www.scopus.com/inward/record.uri?eid=2-s2.0-63049098820&doi=10.1029%2f2008JB005750&partnerID=40&md5=deec537dc06f6a9c313d3cf7c2b1cbac cited By 60 W. Tanikawa T. Shimamoto article WrightHortonJr.200921 The International Continental Scientific Drilling Program (ICDP)-U.S. Geological Survey (USGS) Eyreville drill cores from the Chesapeake Bay impact structure provide one of the most complete geologic sections ever obtained from an impact structure. This paper presents a series of geologic columns and descriptive lithologic information for the lower impactite and crystalline-rock sections in the cores. The lowermost cored section (1766-1551 m depth) is a complex assemblage of mica schists that commonly contain graphite and fibrolitic sillimanite, intrusive granite pegmatites that grade into coarse granite, and local zones of mylonitic deformation. This basement-derived section is variably overprinted by brittle cataclastic fabrics and locally cut by dikes of polymict impact breccia, including several suevite dikes. An overlying succession of suevites and lithic impact breccias (1551-1397 m) includes a lower section dominated by polymict lithic impact breccia with blocks (up to 17 m) and boulders of cataclastic gneiss and an upper section (above 1474 m) of suevites and clast-rich impact melt rocks. The uppermost suevite is overlain by 26 m (1397-1371 m) of gravelly quartz sand that contains an amphibolite block and boulders of cataclasite and suevite. Above the sand, a 275-m-thick allochthonous granite slab (1371-1096 m) includes gneissic biotite granite, fine- and medium-to-coarse-grained biotite granites, and red altered granite near the base. The granite slab is overlain by more gravelly sand, and both are attributed to debris-avalanche and/or rockslide deposition that slightly preceded or accompanied seawater-resurge into the collapsing transient crater. © 2009 The Geological Society of America. 2009 10.1130/2009.2458(02) Special Paper of the Geological Society of America 458 21-49 U.S. Geological Survey, 12201 Sunrise Valley Drive, Reston, VA 20192, United States; Impact Cratering Research Group, School of Geosciences, University of the Witwatersrand, P.O. Wits, Johannesburg 2050, South Africa; Museum für Naturkunde-Leibniz Institute, Humboldt University Berlin, Invalidenstrasse 43, 10115 Berlin, Germany; Lunar and Planetary Institute, 3600 Bay Area Boulevard, Houston, TX 77058-1113, United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-74949138582&doi=10.1130%2f2009.2458%2802%29&partnerID=40&md5=27102863d25ef1c8ea299619c263b6e4 cited By 40 J. Wright Horton Jr. R.L. Gibson W.U. Reimold A. Wittmann G.S. Gohn L.E. Edwards article Gilli2009723 The surface geology of the site of the Chicxulub impact crater in northwestern Yucatán, Mexico, has not been studied extensively since the discovery of the crater almost two decades ago. Strontium isotope (87Sr/86Sr) measurements in carbonate rock outcrops reveal near-uniform strontium signatures of 0.70905 inside the ring of cenotes (water-filled sinkholes), which represents the rim of the crater basin. Measured strontium isotope ratios were used to infer rock ages, employing the marine Sr isotope curve. We estimate the age of the exposed limestone within the Chicxulub crater basin to be late Miocene to early Pliocene, representing the age of the youngest sediment fill. Discovery of a large terrain of near-uniform strontium isotope ratios in northwestern Yucatán offers new geoarchaeological opportunities to track ancient Maya migration and determine sources of manufactured goods. Our results have implications for applying the Sr isotope method to Maya archaeological sites, such as Mayapán, the last Maya capital, and Chichén Itzá. © 2009 Geological Society of America. 2009 10.1130/G30098A.1 Geology 37 723-726 Geological Institute, ETH Zurich, Sonneggstrasse 5, 8092 Zurich, Switzerland; Department of Geological Sciences, Land Use and Environmental Change Institute (LUECI), University of Florida, 241 Williamson Hall, Gainesville, FL 32611, United States; Godwin Laboratory for Palaeoclimate Research, Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ, United Kingdom 8 https://www.scopus.com/inward/record.uri?eid=2-s2.0-69649097569&doi=10.1130%2fG30098A.1&partnerID=40&md5=d4933b5a2cbf92877b6218db629bc54a cited By 19 A. Gilli D.A. Hodell G.D. Kamenov M. Brenner article Rutqvist20091 In this simulation study, we analyzed the geomechanical response during depressurization production from two known hydrate-bearing permafrost deposits: the Mallik (Northwest Territories, Canada) deposit and Mount Elbert (Alaska, USA) deposit. Gas was produced from these deposits at constant pressure using horizontal wells placed at the top of a hydrate layer (HL), located at a depth of about 900 m at the Mallik site and 600 m at the Mount Elbert site. The simulation results show that general thermodynamic and geomechanical responses are similar for the two sites, but with substantially higher production and more intensive geomechanical responses at the deeper Mallik deposit. The depressurization-induced dissociation begins at the well bore and then spreads laterally, mainly along the top of the HL. The depressurization results in an increased shear stress within the body of the receding hydrate and causes a vertical compaction of the reservoir. However, its effects are partially mitigated by the relatively stiff permafrost overburden, and compaction of the HL is limited to less than 0.4%. The increased shear stress may lead to shear failure in the hydrate-free zone bounded by the HL overburden and the downward-receding upper dissociation interface. This zone undergoes complete hydrate dissociation, and the cohesive strength of the sediment is low. We determined that the likelihood of shear failure depends on the initial stress state as well as on the geomechanical properties of the reservoir. The Poisson's ratio of the hydrate-bearing formation is a particularly important parameter that determines whether the evolution of the reservoir stresses will increase or decrease the likelihood of shear failure. 2009 English 09204105 10.1016/j.petrol.2009.02.013 Journal of Petroleum Science and Engineering 67 1-12 Earth Sciences Division, Lawrence Berkeley National Laboratory, MS 90-1116, Berkeley, CA 947 20, United States; Petroleum Engineering Department, Texas A and M University, MS 3116, Richardson Building, College Station, TX 77843, United States; US Geological Survey, Denver Federal Center, P.O. Box 25046, MS-939, Denver, CO 80225, United States 1-2 Alaska , usa; Cohesive strengths; Constant pressures; depressurization; Gas productions; Geomechanical properties; geomechanics; hydrate dissociation; Induced dissociations; Initial stress state; Poisson's ratios; Reservoir stress; Shear failures; Simulation results; Simulation studies; Well bores, Bearings (structural); Compaction; Dissociation; Gases; Horizontal wells; Hydration; International trade; Oil wells; Permafrost; Poisson ratio; Shear stress; Strength of materials, Gas hydrates, computer simulation; gas hydrate; permafrost; Poisson ratio; shear stress; soil mechanics; thermodynamics https://www.scopus.com/inward/record.uri?eid=2-s2.0-67349248544&doi=10.1016%2fj.petrol.2009.02.013&partnerID=40&md5=39a8fc288d8e34726ca9c00a1e61f204 cited By 175 J. Rutqvist G.J. Moridis T. Grover T. Collett article Plescia2009181 The Chesapeake Bay impact structure is a complex impact crater, ̃85 km in diameter, buried beneath postimpact sediments. Its main structural elements include a central uplift of crystalline bedrock, a surrounding inner crater filled with impact debris, and an annular faulted margin composed of block-faulted sediments. The gravity anomaly is consistent with that of a complex impact consisting of a central positive anomaly over the central uplift and an annular negative anomaly over the inner crater. An anomaly is not recognized as being associated with the faulted margin or the outer edge of the structure. Densities from the Eyreville drill core and modeling indicate a density contrast of ̃0.3-0.6 g cm -3 between crystalline basement and the material that fills the inner crater (e.g., Exmore breccia and suevite). This density contrast is somewhat higher than for other impact structures, but it is a function of the manner in which the crater fill was deposited (as a marine resurge deposit). Modeling of the gravity data is consistent with a depth to basement of ̃1600 m at the site of Eyreville drill hole and 800 m at the central uplift. Both depths are greater than the depth at which crystalline rocks were encountered in the cores, suggesting that the cored material is highly fractured para-allochthonous rock. © 2009 The Geological Society of America. 2009 English 00721077 10.1130/2009.2458(09) Special Paper of the Geological Society of America 458 Geological Society of America 181-193 Applied Physics Laboratory, Johns Hopkins University, Laurel, MD 20723-6099, United States; U.S. Geological Survey, Eastern Mineral Resource Team, Reston, VA 20192, United States; U.S. Geological Survey, Crustal Imaging and Characterization Team, Federal Center, Box 25046, Denver, CO 80225-0046, United States Buildings; Core drilling; Crystalline materials; Drills; Infill drilling, Allochthonous rocks; Chesapeake bay impact structures; Crystalline basement; Crystalline bedrocks; Depth to basements; Gravity anomalies; Impact structures; Structural elements, Crystalline rocks, basement rock; bedrock; crater; crystalline rock; gravity anomaly; impact structure; uplift, Chesapeake Bay; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-74949097381&doi=10.1130%2f2009.2458%2809%29&partnerID=40&md5=5b5a4709185a3e3e44c33ab91bf24ab2 cited By 6 J.B. Plescia D.L. Daniels A.K. Shah article Perry200927 We report 87Sr/86Sr and ion concentrations of sulfate, chloride, and strontium in the groundwater of the northern and central Yucatan Peninsula, Mexico. Correlation between these data indicates that ejecta from the 65.95 m.y. old Chicxulub impact crater have an important effect on hydrogeology, geomorphology, and soil development of the region. Ejecta are present at relatively shallow subsurface depths in north-central Yucatan and at the surface along the Rio Hondo escarpment in southeast Quintana Roo, where they are referred to as the Albion Formation. Anhydrite/gypsum (and by inference celestite) are common in impact ejecta clasts and in beds and cements of overlying Paleocene and Lower Eocene rocks cored around the margin of the crater. The sulfate-rich minerals that are found in rocks immediately overlying the impact ejecta blanket, may either be partially mobilized from the ejecta layer itself or may have been deposited after the K/T impact event in an extensive pre-Oligocene shallow sea. These deposits form a distinctive sedimentary package that can be easily traced by the Eocene-Cretaceous 87Sr/86Sr signal. A distinct Sr isotopic signature and high SO4/Cl ratios are observed in groundwater of northwestern and north-central Yucatan that interacts with these rocks. Moreover, the distribution of the gypsum-rich stratigraphic unit provides a solution-enhanced subsurface drainage pathway for a broad region characterized by dissolution features (poljes) extending from Chetumal, Quintana Roo to Campeche, Campeche. The presence of gypsum quarries in the area is also consistent with a sulfate-rich stratigraphic "package" that includes ejecta. The distinctive chemistry of groundwater that has been in contact with evaporite/ejecta can be used to trace flow directions and confirms a groundwater divide in the northern Peninsula. Information about groundwater flow directions and about deep subsurface zones of high permeability is useful for groundwater and liquid waste management in the area. Where it discharges at the coast, the unique chemistry of the groundwater that has interacted with the evaporite/ejecta strata may also have significant geomorphologic implications. While groundwater-seawater mixing at the coast has been shown to dissolve and erode limestone, PHREEQC modeling shows that mixing of water nearly saturated in CaSO4 with seawater has a less vigorous dissolution effect due to its high Ca content. © 2009 Elsevier B.V. All rights reserved. 2009 10.1016/j.jhydrol.2008.12.026 Journal of Hydrology 367 27-40 Department of Geology and Environmental Geosciences, Northern Illinois University, Davis Hall 312, DeKalb, IL 60115, United States; Institute of Marine Sciences University of California Santa Cruz, Santa Cruz, CA 95064, United States; Cancun Q.R., Mexico 1-2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-60549095828&doi=10.1016%2fj.jhydrol.2008.12.026&partnerID=40&md5=5d9f6e72c254ec7413ff07fbc30f1d6c cited By 96 E. Perry A. Paytan B. Pedersen G. Velazquez-Oliman article Barton200914 The processes that accompany asteroid impact and the roles they play in creating or destroying petroleum source rocks, reservoirs and traps are discussed. Most asteroids orbit the Sun in the asteroid belt, which lies between Mars and Jupiter but some come closer to the Earth. Excavation produces a bowl-shaped transient crater. Craters larger than a few kilometers in diameter usually have complex morphologies characterized by an uplift central area. The central high consists of shocked target rock that has been structurally uplifted by rebound. The bottom of the crater filled with melt brecias, mixtures of granite, carbonate, and dolomite in a spherulitic matrix. The impact that has drawn the most attention is the collision of the Chicxulub impactor with what is now the Mexican Yucatán Peninsula. A direct hit by an asteroid can also cause the demise of an hydrocarbon accumulation. 2009 Oilfield Review 21 14-29 True Oil LLC Casper, Wyoming, United States; US Geological Survey, Menlo Park, CA, United States; PEMEX Villahermosa, Tabasco, Mexico; Mexican Petroleum Institute, Mexico City, Mexico; University of Colorado, Boulder, CO, United States; University of Vienna, Vienna, Austria; Continental Resources, Inc., Enid, OK, United States 4 https://www.scopus.com/inward/record.uri?eid=2-s2.0-77950981776&partnerID=40&md5=d2fcda7d025e4e1be37612210d4e25b6 cited By 15 R. Barton K. Bird J.G. Hernández J.M. Grajales-Nishimura G. Murillo-Muñetón B. Herber P. Weimer C. Koeberl M. Neumaier O. Schenk J. Stark article Shervais2009141 Basaltic volcanism in the western Snake River Plain underwent an abrupt change circa ~ 700 ka to 900 ka, from low-K tholeiitic basalt and ferrobasalt to high-K transitional alkali basalt. The low-K tholeiitic basalts share major element, trace element, and isotopic characteristics with olivine tholeiites of the eastern Snake River Plain, and must have been derived by similar processes from similar sources. In contrast, the younger high-K alkali basalts share major element, trace element, and isotopic characteristics with plume-derived alkali basalts of ocean islands suites like Hawaii. We conclude that this abrupt transition reflects either or both the erosion of pre-existing mantle lithosphere in the wake of the Yellowstone-Snake River plume, or the depletion of this lithosphere in fusible components so that it no longer contributed to the overall mass flux of magma. The abruptness of the transition implies that it may have a catastrophic origin, such as lithospheric delamination caused by a Rayleigh-Taylor instability beneath the Idaho batholith. © 2009 Elsevier B.V. All rights reserved. 2009 English 03770273 10.1016/j.jvolgeores.2009.01.023 Journal of Volcanology and Geothermal Research 188 141-152 Department of Geology, Utah State University, Logan, UT 84322-4505, United States; Department of Geology, Centenary College, Shreveport, LA 71134, United States 1-3 Abrupt change; Abrupt transition; Alkali basalt; Alkaline plumes; Basaltic volcanism; Hotspots; Idaho Batholith; Isotopic characteristics; Lithospheric; Major elements; Mantle lithosphere; Mass flux; Rayleigh-Taylor instabilities; Snake River; Snake river plains; SRP; Tholeiitic basalts; Yellowstone plume; Yellowstones, Isotopes; Oceanography; Olivine; Rivers; Sedimentary rocks; Silicate minerals; Trace elements, Basalt, alkali basalt; alkaline rock; hot spot; mantle plume; ocean island basalt; tholeiite; trace element; volcanism, Idaho; North America; Snake River Plain; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-71749107576&doi=10.1016%2fj.jvolgeores.2009.01.023&partnerID=40&md5=3f84660d1f74e44ff589eb6d8e4f3a3e cited By 14 J.W. Shervais S.K. Vetter article Kawaragi200956 Shock-induced devolatilization in hypervelocity impacts has been considered to play important roles in the atmospheric evolution and mass extinctions in Earth's history. Although the chemical composition of shock-induced gas species from carbonate rocks has been considered as a key to understand the environmental change after the Chicxulub impact, it has not been investigated extensively before. Here, we conduct direct measurements of the chemical composition (CO/CO2) of shock-induced gas species from calcite (CaCO3) using both a laser gun system and an isotopic labeling technique. The CO/CO2 ratio of the shock-induced gas species from calcite is measured to be 2.02 ± 0.41, suggesting that gaseous CO has been dominant in the shock-induced gases in the Chicxulub impact. In order to evaluate the environmental effects of the injection of CO gas, we investigated the post-impact atmospheric chemistry by incorporating our experimental results into a tropospheric photochemical model. The results suggest that an intense (2-5 °C) global warming would have lasted for several years after a Chicxulub-size impact mainly due to the greenhouse effect of tropospheric O3, which is produced via photochemical reactions associated with CO gas. Such an intense global warming could have damaged the biosphere in the mass extinction at the Cretaceous-Paleogene (K-P) boundary. © 2009 Elsevier B.V. All rights reserved. 2009 10.1016/j.epsl.2009.02.037 Earth and Planetary Science Letters 282 56-64 Department of Complexity Science and Engineering, Graduate School of Frontier Sciences, University of Tokyo, 5-1-5, Kashiwanoha, Kashiwa, Chiba, 277-8561, Japan; Institute of Laser Engineering Osaka University, 2-6 Yamadaoka, Suita, Osaka, 565-0871, Japan; Institute for Study of the Earth's Interior, Okayama University, 827 Yamada, Misasa, Tottori, 682-0193, Japan; Department of Earth and Planetary Science, Graduate School of Science, University of Tokyo, 5-1-5, Kashiwanoha, Kashiwa, Chiba, 277-8561, Japan 1-4 https://www.scopus.com/inward/record.uri?eid=2-s2.0-67349202838&doi=10.1016%2fj.epsl.2009.02.037&partnerID=40&md5=d62acb0a5af817d243acf51a9d60a93f cited By 30 K. Kawaragi Y. Sekine T. Kadono S. Sugita S. Ohno K. Ishibashi K. Kurosawa T. Matsui S. Ikeda article Carpenter2009 We report on frictional properties of rocks within the 3-D crustal volume surrounding the San Andreas Fault Observatory at Depth (SAFOD). Samples include lithologies adjacent to the San Andreas Fault (SAF) in the subsurface, SAFOD borehole rocks, and synthetic fault gouge composed of talc, serpentinite, and quartz. Granodiorite, arkosic sandstone, and siltstone samples from the SAFOD borehole are frictionally strong (μ = 0.56 - 0.66). Sand and clay-rich lithologies from outcrop exhibit friction in the range /x = 0.56 - 0.68. Natural serpentinite thought to abut the SAF at depth exhibits low friction (μ = 0.18 - 0.26). Our results indicate that 1) serpentinite exhibits low strength, but is not weak enough to completely satisfy weak fault models, 2) all other samples are consistent with a strong fault and crust and, 3) if the SAF is weak (μ ≤ 0.2) due to the presence of serpentinite or talc, these minerals would likely need to constitute over 50% by weight of the shear zone. Copyright 2009 by the American Geophysical Union. 2009 English 00948276 10.1029/2008GL036660 Geophysical Research Letters 36 Department of Geosciences, Energy Institute Center for Geomechanics, Geofluids, and Geohazards, Pennsylvania State University, University Park, PA, United States; Department of Geosciences, Energy Institute Center for Geomechanics, Geofluids, and Geohazards, Pennsylvania State University, University Park, PA 16802, United States 5 Fault gouge; Fault model; Frictional behavior; Frictional properties; Granodiorite; Low friction; San Andreas Fault; Serpentinite; Shear zone; Siltstone, Clay minerals; Friction; Oxide minerals; Petrology; Quartz; Silicate minerals; Talc, Three dimensional, borehole; fault gouge; fault zone; friction; granodiorite; lithology; outcrop; quartz; rock mechanics; sandstone; serpentinite; shear zone; siltstone; strength; talc, California; North America; San Andreas; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-65649106899&doi=10.1029%2f2008GL036660&partnerID=40&md5=879e0e1c25af51b6c6c960780e797f2b cited By 77 B.M. Carpenter C. Marone D.M. Saffer article WrightHortonJr.200921 The International Continental Scientific Drilling Program (ICDP)-U.S. Geological Survey (USGS) Eyreville drill cores from the Chesapeake Bay impact structure provide one of the most complete geologic sections ever obtained from an impact structure. This paper presents a series of geologic columns and descriptive lithologic information for the lower impactite and crystalline-rock sections in the cores. The lowermost cored section (1766-1551 m depth) is a complex assemblage of mica schists that commonly contain graphite and fibrolitic sillimanite, intrusive granite pegmatites that grade into coarse granite, and local zones of mylonitic deformation. This basement-derived section is variably overprinted by brittle cataclastic fabrics and locally cut by dikes of polymict impact breccia, including several suevite dikes. An overlying succession of suevites and lithic impact breccias (1551-1397 m) includes a lower section dominated by polymict lithic impact breccia with blocks (up to 17 m) and boulders of cataclastic gneiss and an upper section (above 1474 m) of suevites and clast-rich impact melt rocks. The uppermost suevite is overlain by 26 m (1397-1371 m) of gravelly quartz sand that contains an amphibolite block and boulders of cataclasite and suevite. Above the sand, a 275-m-thick allochthonous granite slab (1371-1096 m) includes gneissic biotite granite, fine- and medium-to-coarse-grained biotite granites, and red altered granite near the base. The granite slab is overlain by more gravelly sand, and both are attributed to debris-avalanche and/or rockslide deposition that slightly preceded or accompanied seawater-resurge into the collapsing transient crater. © 2009 The Geological Society of America. 2009 English 00721077 10.1130/2009.2458(02) Special Paper of the Geological Society of America 458 Geological Society of America 21-49 U.S. Geological Survey, 12201 Sunrise Valley Drive, Reston, VA 20192, United States; Impact Cratering Research Group, School of Geosciences, University of the Witwatersrand, P.O. Wits, Johannesburg 2050, South Africa; Museum für Naturkunde-Leibniz Institute, Humboldt University Berlin, Invalidenstrasse 43, 10115 Berlin, Germany; Lunar and Planetary Institute, 3600 Bay Area Boulevard, Houston, TX 77058-1113, United States Biotite; Crystalline materials; Crystalline rocks; Granite; Infill drilling; Levees; Mica; Silicate minerals, Biotite granite; Chesapeake bay impact structures; Coarse-grained; Continental scientific drillings; Debris avalanches; Impact structures; Mylonitic deformation; U.s. geological surveys, Core drilling, crater; crystalline rock; deformation; impact structure; impactite; lithology; pegmatite, Chesapeake Bay; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-74949138582&doi=10.1130%2f2009.2458%2802%29&partnerID=40&md5=27102863d25ef1c8ea299619c263b6e4 cited By 40 J. Wright Horton Jr. R.L. Gibson W.U. Reimold A. Wittmann G.S. Gohn L.E. Edwards article Liu2009318 The Chinese Continental Scientific Drilling (CCSD) project, part of the International Continental Drilling Program (ICDP), has completed drilling a 5158 m hole in the eastern part of the Dabie-Sulu ultrahigh-pressure metamorphic belt. This study reports on an apatite fission track analysis of core samples from 0 to 4000 m depth in the CCSD main hole (CCSD-MH). We determined the fission track ages of 38 apatite samples from different depths. The ages range between 98.6 ± 17.0 and 3.2 ± 1.3 Ma, showing a general decreasing trend with depth, from 87.1 ± 11.2 Ma at the surface to 3.2 ± 1.3 Ma at 3899 m depth. As a first approximation, an average uplift rate of ~ 35 m/Ma is calculated for the period 90-30 Ma. The trend in ages within the borehole shows some fluctuations, and indicates movements along major faults. It is inferred that the highest-level major normal fault occurs at a depth of ~ 350 m, recording a vertical displacement of ~ 400 m. Movement along another prominent normal fault at a depth of ~ 2150 m occurred subsequent to ~ 25 Ma. Three major reverse faults occur at about 2450, 3050 and 3250 m depth. Testing geological constrains against the fission track data set indicated an agreement with a reheating of the area during the late Cretaceous and Eocene, followed by cooling to ~ 80 °C during the Eocene and a low cooling until the samples reached their present-day position in the Donghai area. © 2009 Elsevier B.V. All rights reserved. 2009 English 00401951 10.1016/j.tecto.2009.03.015 Tectonophysics 475 318-326 Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, 510640, China; Institute of Earth Sciences, Research Group: Thermochronology and Archaeometry, University of Heidelberg, D-69120 Heidelberg, Germany; Max-Planck-Institute of Nuclear Physics, D-69117 Heidelberg, Germany; Institute of Geology, Chinese Academy of Geological Sciences, Beijing, 100037, China 2 CCSD; Donghai; Fission track dating; Thermochronology; Ultrahigh-pressure metamorphic belt, Apatite; Cooling; Drilling; Fission reactions; Metamorphic rocks; Phosphate minerals; Statistical tests, Boreholes, age determination; apatite; borehole geophysics; Chinese Continental Scientific Drilling Project; displacement; fission track dating; geochronology; normal fault; thermochronology; ultrahigh pressure metamorphism; uplift, Asia; China; Dabie-Sulu Belt; Donghai [Jiangsu]; Eurasia; Far East; Jiangsu https://www.scopus.com/inward/record.uri?eid=2-s2.0-70349100094&doi=10.1016%2fj.tecto.2009.03.015&partnerID=40&md5=f9bf10919520c5502271f4634875b2c0 cited By 13 S.S. Liu U. Weber U.A. Glasmacher Z.Q. Xu G.A. Wagner article Fulton2009 Heat flow data near the San Andreas Fault (SAF) do not reveal a near-fault anomaly as expected from frictional heat generation, an observation interpreted to indicate that the fault slips at a depth-averaged shear stress <20 MPa. The data also contain large unexplained scatter, which has been a separate major issue in the analysis of heat flow within the California Coast Ranges. Here we use numerical models of heat conduction to evaluate the hypothesis that thermal refraction, due to contrasts in thermal conductivity in the subsurface, both produces the observed scatter in heat flow and as a result obscures the thermal signature from frictional heating on a fault that supports large shear stress during slip. Our study focuses on the region around the San Andreas Fault Observatory at Depth (SAFOD) near Parkfield, California. Our results show that surface heat flow is most sensitive to the contrast between Tertiary sediments and basement rocks and to wavelengths of basement topography of ∼10 km. With realistic thermal conductivity contrasts and a reasonable interpretation of this geologic contact, we show that thermal refraction is a plausible explanation for the observed heat flow scatter. However, refraction effects are unable to mask frictional heat generation in a manner consistent with observations. We show that even with large refraction effects, low background heat flow, a regional NW-SE decrease in heat flow, or nonsteady state heat conduction, the data are most consistent with a fault that produces little to no frictional heat. Copyright 2009 by the American Geophysical Union. 2009 English 21699313 10.1029/2008JB005796 Journal of Geophysical Research: Solid Earth 114 Blackwell Publishing Ltd College of Oceanic and Atmospheric Sciences, Oregon State University, 104 COAS Building, Corvallis, OR 97331, United States; Department of Geosciences, Pennsylvania State University, 310 Deike Building, University Park, PA 16802-0000, United States 6 basement rock; coastal zone; data acquisition; fault slip; flow measurement; friction; heat flow; numerical model; shear stress; slip; subsurface flow; thermal conductivity, California; North America; San Andreas; United States, Calluna vulgaris https://www.scopus.com/inward/record.uri?eid=2-s2.0-70349470855&doi=10.1029%2f2008JB005796&partnerID=40&md5=3d6073c8a4af6983f3d3e546761a5051 cited By 14 P.M. Fulton D.M. Saffer article Mrlina200997 Based on results of previous investigations of tephra-tuff volcaniclastic deposits and a geophysical survey in the surroundings of the Železná hůrka Quaternary volcano, West Bohemia, we performed detailed geophysical surveys using gravimetry, magnetometry and electrical conductivity techniques. Striking anomalies were revealed in a morphological depression near Mýtina, West Bohemia, as a strong evidence of the assumed maar-diatreme structure. The sharp isometric gravity low of - 2.30 mGal, as well as the corresponding positive magnetic anomaly of 200 nT with a negative rim on its northern side indicate a steeply dipping geological body of low density and containing magnetic rocks/minerals. Magnetic survey also showed pronounced local anomalies outside the depression that can reflect relicts of the tephra rim of the maar. This geophysical evidence was then proven by an exploratory drilling near the centre of the gravity anomaly. Macroscopic on-site evaluation of the core, and more detailed sedimentological, petrochemical, palynological and microbiological laboratory analyses further confirmed the existence of a maar structure filled by 84 m of lake sediments reflecting a succession of several warm and cold climatic periods. Results of palynological analyses confirm the presence of a continuous palaeoclimate archive, with at least three successive warmer periods of most probably interstadial character from the upper Quaternary Saalian complex. Therefore, the recovered sediment sequence holds strong potential for in-depth paleoclimate reconstruction and deep biosphere studies. At the bottom of the Mýtina-1 (MY-1) borehole (84-85.5 m), country rock debris was found, containing also volcanic bombs and lapilli. The discovered volcanic structure is considered to be the first known Quaternary maar-diatreme volcano on the territory of the Bohemian Massif. Because of hidden active magmatic processes in combination with earthquake swarm seismicity ca. 20-30 km north of the Mýtina maar, reconstruction of the palaeovolcanological evolution is important for evaluation of hazard potential of the NE and E part of the Cheb Basin. © 2009 Elsevier B.V. All rights reserved. Article 2009 English 03770273 10.1016/j.jvolgeores.2009.01.027 Journal of Volcanology and Geothermal Research 182 97 – 112 1-2 Bohemian Massif; Central Europe; Eurasia; Europe; Debris; Earthquakes; Electric conductivity; Geological surveys; Geophysics; Gravitational effects; Hazards; Lakes; Minerals; Restoration; Sedimentology; Structural geology; Volcanoes; Eger Rift; geophysical survey; Quaternary maar volcanism; Saalian lake sediments; volcanic hazard potential; diatreme; earthquake swarm; electrical conductivity; geophysical survey; gravimetry; gravity anomaly; maar; magnetic anomaly; magnetometer; paleoclimate; paleoseismicity; Quaternary; Saalian; tephra; tuff; volcaniclastic deposit; Core analysis https://www.scopus.com/inward/record.uri?eid=2-s2.0-64149113281&doi=10.1016%2fj.jvolgeores.2009.01.027&partnerID=40&md5=ce0407aadd492a273d74b5657f490223 Cited by: 83 J. Mrlina H. Kämpf C. Kroner J. Mingram M. Stebich A. Brauer W.H. Geissler J. Kallmeyer H. Matthes M. Seidl article Heidinger2009931 The Chesapeake Bay impact structure is a late Eocene complex crater that was excavated -35 Ma ago in a continental shelf environment at the Atlantic margin, in Virginia. It is the largest impact structure in the United States and the seventh largest on Earth. It has an average diameter of -85 km and is centered near Cape Charles. The scientific well Eyreville B drilled within the framework of the International Continental Scientific Drilling Program (ICDP) penetrated the deep crater moat -9 km from the center of the structure. Core holes drilled in impact structures are especially suited for investigations of the infl uence of lithological heterogeneities on petrophysical properties and the thermal field. In the Eyreville B core hole, two high-resolution temperature-logging campaigns and a petrophysical profile measured on core samples spaced at -10 m intervals were recorded. The temperature values of the first campaign in December 2005 were heavily disturbed by outflow of artesian water and could only be used for an estimation of the depth where the fluid originated. For the second campaign in May 2006, a riser was constructed to enable measurements in standing (equilibrated) fluid of the well without opening the well head. This construction yielded a measurement of the undisturbed temperature profile as well as recognition of thermal relaxation after some outflow of artesian water, which wellheated the surrounding rock. The data allowed determination of (1) the origin of the artesian water, (2) equilibrium temperatures derived from the relaxation process, (3) microclimatic effects at the nearby test well STP2, (4) lateral heterogeneities in the core holes STP2 and Eyreville B, and (5) a profile of vertical heat-flow density in the Eyreville B core. From the calculated vertical component of the thermal gradient and the thermal conductivity measured on core samples, a mean heat-flow density of 65 ± 6 mW/m2 in the 440-1100 m depth interval was determined. These data and results are now available for application in numerical models of the local and regional geologic, hydrologic, and geothermal regimes. © 2009 The Geological Society of America. 2009 English 00721077 10.1130/2009.2458(39) Special Paper of the Geological Society of America 458 Geological Society of America 931-940 Geophysical Institute, University of Karlsruhe, Hertzstrasse 16, 76187 Karlsruhe, Germany; Russian State Geological Prospecting University, Miklukho-Maklai 23, Moscow 117997, Russian Federation; Institute of Geophysics, Bocní II/1401, 14131 Prague 4, Czech Republic; Institute of Applied Geosciences, Technical University of Berlin, Ackerstrasse 71-76, 13355 Berlin, Germany; FR Geophysics, Freie Universität Berlin, Malteserstrasse 74-100, 12249 Berlin, Germany Heat transfer; Infill drilling; Lithology; Petrophysics; Thermal conductivity; Wellheads, Chesapeake bay impact structures; Continental scientific drillings; Continental shelves; Equilibrium temperatures; Lateral heterogeneity; Microclimatic effects; Petrophysical properties; Temperature profiles, Core samples, borehole; continental shelf; crater; Eocene; estimation method; geothermal system; heat flow; impact structure; lithology; numerical model; temperature profile; thermal conductivity; thermal regime, Chesapeake Bay; United States; Virginia, Calluna vulgaris https://www.scopus.com/inward/record.uri?eid=2-s2.0-74949090699&doi=10.1130%2f2009.2458%2839%29&partnerID=40&md5=5f711d43ba2baf2e4bd3d4be0a3fc7ad cited By 8 P. Heidinger H. Wilhelm Y. Popov J. Šafanda H. Burkhardt S. Mayr article Tierney20091032 Branched glycerol dialkyl glycerol tetraether (GDGT) lipids are abundant and ubiquitous in lake sediments, potentially allowing for a paleolimnological application of the so-called MBT/CBT proxy (methylation index of branched tetraethers/cyclization ratio of branched tetraethers). To investigate the origin and characteristics of these compounds in lacustrine environments, we examined the distributions of GDGTs in soils, river sediments and lake sediments from Lake Towuti on the island of Sulawesi, Indonesia. We found significant differences in the degree of methylation and cyclization (expressed by way of the MBT and CBT indices) between the soil samples and the aquatic samples, suggesting that there may be in situ production of GDGTs in the aquatic environment. Based on these findings, we urge caution in the application of the MBT/CBT paleoproxy to lake sediments and encourage more rigorous study of these compounds in freshwater environments. © 2009 Elsevier Ltd. All rights reserved. Article 2009 English 01466380 10.1016/j.orggeochem.2009.04.014 Organic Geochemistry 40 1032 – 1036 9 Asia; Eurasia; Indonesia; Lake Towuti; Malili Lakes; South Sulawesi; Southeast Asia; Alkylation; Glycerol; Lakes; Methylation; Sedimentology; Soils; Aquatic environments; Degree of methylations; Freshwater environments; In-situ production; Indonesia; Lake sediments; River sediments; Soil sample; Tropical lakes; ether; fluvial deposit; lacustrine deposit; lacustrine environment; lipid; methylation; tropical environment; Sediments https://www.scopus.com/inward/record.uri?eid=2-s2.0-68749095059&doi=10.1016%2fj.orggeochem.2009.04.014&partnerID=40&md5=22404412ed8b1b0683345e032befae4a Cited by: 213 Jessica E. Tierney James M. Russell article JI2009201 2009 0040-1951 https://doi.org/10.1016/j.tecto.2009.04.007 Tectonophysics 475 201-203 2 https://www.sciencedirect.com/science/article/pii/S0040195109002169 The Chinese Continental Scientific Drilling Shaocheng Ji Zhiqin Xu article koeberl2009drilling 2009 Meteoritics and Planetary Science Supplement 72 5014 Christian Koeberl Julie Brigham-Grette Martin Melles Pavel Minyuk article Farnetani2009314 Geochemical studies, including those made possible by the Hawaiian Scientific Drilling Project, have revealed the chemically and isotopically heterogeneous nature of hotspot lavas, yet their interpretation is highly controversial and there is little agreement as to how geochemical heterogeneities might be spatially arranged within the plume conduit. To address this issue we conduct high resolution numerical simulations of an axisymmetric purely thermal plume, focusing on the lower mantle part of the conduit and on the thermal boundary layer (TBL) feeding the plume. We explore the relation between length-scales of heterogeneities across the source region and the length- and time-scales of geochemical variations in the plume conduit. The vertical velocity inside the conduit decreases exponentially with the square of radial distance generating high strain rates (order 10- 13-10- 14 s- 1) that modify the shape of upwelling heterogeneities into elongated and narrow filaments. Therefore, the preservation of 'blob-like' heterogeneities (i.e., with a 1:1 aspect ratio in a vertical section) is quite unlikely, even in the central part of the plume. For example, initial lenses of size 100 × 10 km in the TBL are stretched into filaments 500-1000 km long. These filaments constitute 'long-lived' structures in a rising plume, and their geochemical fingerprints may be registered at a given radial distance for several millions of years. We also consider an idealized heterogeneous architecture inside the TBL, consisting of 'trains' of small scale lenses. When such trains upwell in the conduit, they form high radial geochemical gradients. Their 'geochemical record', registered over time at a given depth and radial distance, will fluctuate over time, with shorter period and a larger amplitude at the conduit center than at its periphery. Finally, we demonstrate that material existing 'side by side' in the conduit originated from regions in the TBL that are separated by distances of several hundred kilometers. This implies that vigorous plumes are able to sample, and to bring side by side, very distant portions of their source region. Our results provide a fluid dynamically consistent framework to discuss the main aspects of the different (and to some extent mutually exclusive) models of conduit structure used to interpret the geochemical observations of the Hawaiian lavas. © 2009 Elsevier B.V. All rights reserved. Article 2009 English 0012821X 10.1016/j.epsl.2009.03.035 Earth and Planetary Science Letters 282 314 – 322 1-4 Hawaii [United States]; North America; United States; Aspect ratio; Filaments (lamp); Lenses; Locomotives; Optical instruments; Railroad cars; Strain rate; Transport properties; Axi-symmetric; Conduit structures; Geochemical fingerprints; geochemical heterogeneity; Geochemical variations; Hawaiian plume; Heterogeneous architectures; High strain rates; High-resolution numerical simulations; Hot spots; Internal structures; Lower mantles; mantle plumes; Radial distances; Scientific drillings; Small scale; Source regions; Thermal boundary layers; Time-scales; Vertical sections; Vertical velocities; isotopic composition; lower mantle; mantle chemistry; mantle plume; numerical model; Thermal plumes https://www.scopus.com/inward/record.uri?eid=2-s2.0-67349118868&doi=10.1016%2fj.epsl.2009.03.035&partnerID=40&md5=5ae64fb76550dcc070f87710260f6f69 Cited by: 68 Cinzia G. Farnetani Albrecht W. Hofmann article Bräuer2009 The detailed processes generating earthquake swarms are complex and not fully understood. Most earthquake swarms occur in volcanic regions and mid-ocean rifts. Here, we report new 3HeZ4He data of free gases monitored at CO2rich degassing locations close to the Nový Kostel focal zone (NKFZ) located in the western Eger rift. The NKFZ is known for the recurrence of earthquake swarms at which the focal zone ranges between 6 and 12 km depth. At degassing locations neighboring to the NKFZ a progressive increase of mantle-derived helium has been observed during the last 15 years - actually the highest 3He/4He ratios (>6 Ra) in Central Europe. The 3HeZ4He anomalies indicate hidden magmatic activity. We assume that the latest strong earthquake swarm in October 2008 was initiated by a hidden magma intrusion process from the upper mantle into the lower crust that has been indicated by a three month lasting increase of the 3HeZ4He ratios in spring 2006 at all degassing locations near the NKFZ. Copyright 2009 by the American Geophysical Union. Article 2009 English 00948276 10.1029/2009GL039615 Geophysical Research Letters 36 American Geophysical Union 17 Central Europe; Eger; Eurasia; Europe; Heves; Hungary; Degassing; Helium; Oceanography; Volcanoes; Central Europe; Earthquake swarms; Focal zones; Free gas; Lower crust; Magma intrusion; Magmatic activity; Upper mantle; Volcanic region; carbon dioxide; degassing; earthquake swarm; helium; lower crust; magmatism; rift zone; upper mantle; Earthquakes https://www.scopus.com/inward/record.uri?eid=2-s2.0-71949086773&doi=10.1029%2f2009GL039615&partnerID=40&md5=4fe8816b997146aab9860df32385cda4 Cited by: 59 Karin Bräuer Horst Kämpf Gerhard Strauch article Senft2009471 Impact craters are the most common landform on planetary surfaces; however, the mechanics of the end stages of their formation are not fully understood. The final stage of crater formation involves the collapse of a hemispherical transient cavity. Around small craters, the limited amount of collapse preserves a bowl-shaped cavity. In contrast, the observed shallow depths and complex inner morphologies of large craters require very low shear strength in the collapsing material. Because the observed amount of collapse cannot be reproduced using quasi-static values for the frictional strength of fractured rock, a temporary weakening mechanism is necessary. Here, we investigate the hypothesis that craters collapse along a network of impact-generated faults that weaken during long displacements at high slip velocities via, for example, frictional melting. Using the CTH shock physics code, we simulate the formation of about 100-km diameter impact craters using a simple strain-rate weakening model with parameters constrained by fault friction experiments on crystalline rocks. The model reduces the coefficient of friction from a quasi-static value (0.6-0.85) to a weakened value (0.1-0.2) when a parcel of fractured material exceeds thresholds for cumulative plastic shear strain (a proxy for slip distance) and shear strain rate (a proxy for slip velocity). During crater formation, the strain-rate weakening model leads to strain localizations that are interpreted to be fault zones. Fault zones are spontaneously created and slip over discrete time intervals during collapse. The strain-rate weakening model reproduces the major geologic features observed around the largest terrestrial craters (Vredefort, Sudbury, and Chicxulub), including shallow depths, fault structures, frictional melt distributions, and deep-seated central uplifts. The good agreement between calculations and observations supports the hypothesis that small volumes of transiently weakened material in fault zones control the collapse of large impact craters. © 2009 Elsevier B.V. All rights reserved. 2009 10.1016/j.epsl.2009.08.033 Earth and Planetary Science Letters 287 471-482 Harvard University, United States 3-4 https://www.scopus.com/inward/record.uri?eid=2-s2.0-70350130551&doi=10.1016%2fj.epsl.2009.08.033&partnerID=40&md5=f11907c03761d7f7a7b196d68e7d0f69 cited By 60 L.E. Senft S.T. Stewart article Janský2009135 We study the efficiency of individual stations of the CRL seismic network in recording the seismic activity in the western Gulf of Corinth, Greece. The stations are located on both the northern and southern coast of the Gulf. The study is based on 5027 earthquakes recorded in 2001, separated into three groups, the southern, central and the northern one. The events were located using the HYPO71PC algorithm. It is shown that the stations significantly differ in their monitoring ability. Article 2009 English 12149705 Acta Geodynamica et Geomaterialia 6 135 – 142 2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-77953777906&partnerID=40&md5=4ab1d78166ac844cf7da18fb2185085a Cited by: 1 Jaromír Janský Jiří Zahradník Vladimír Plicka article Kern2009151 The Outokumpu scientific deep drill hole intersects a 2500 m deep Precambrian crustal section comprising a 1300 m thick biotite-gneiss series (mica schists) at top, followed by a 200 m thick meta-ophiolite sequence, underlain again by biotite gneisses (mica schists) (500 m thick) with intercalations of amphibolite and meta-pegmatoids (pegmatitic granite). From 2000 m downward the dominating rock types are meta-pegmatoids (pegmatitic granite). Average isotropic intrinsic P- and S-wave velocities and densities of rocks were calculated on the basis of the volume fraction of the constituent minerals and their single crystal properties for 29 core samples covering the depth range 198-2491 m. The modal composition of the rocks is obtained from bulk rock (XRF) and mineral chemistry (microprobe), using least squares fitting. Laboratory seismic measurements on 13 selected samples representing the main lithologies revealed strong anisotropy of P- and S-wave velocities and shear wave splitting. Seismic anisotropy is strongly related to foliation and is, in particular, an important property of the biotite gneisses, which dominate the upper and lower gneiss series. At in situ conditions, velocity anisotropy is largely caused by oriented microcracks, which are not completely closed at the pressures corresponding to the relatively shallow depth drilled by the borehole, in addition to crystallographic preferred orientation (CPO) of the phyllosilicates. The contribution of CPO to bulk anisotropy is confirmed by 3D velocity calculations based on neutron diffraction texture measurements. For vertical incidence of the wave train, the in situ velocities derived from the lab measurements are significantly lower than the measured and calculated intrinsic velocities. The experimental results give evidence that the strong reflective nature of the ophiolite-derived rock assemblages is largely affected by oriented microcracks and preferred crystallographic orientation of major minerals, in addition to the lithologic control. © 2009 Elsevier B.V. All rights reserved. Article 2009 English 00319201 10.1016/j.pepi.2009.03.009 Physics of the Earth and Planetary Interiors 175 151 – 166 3-4 Anisotropy; Crystallography; Curve fitting; Elasticity; Fatigue of materials; Granite; Intercalation; Lithology; Mica; Mineralogy; Mining; Rock drills; Rocks; Seismic waves; Seismology; Shear waves; Silica; Silicate minerals; Single crystals; Three dimensional; Velocity; 3d velocities; Biotite gneiss; Bulk rocks; Crustal rocks; Crystallographic orientations; Crystallographic preferred orientations; Depth ranges; Elastic wave velocities; In-situ; Intrinsic velocities; Least squares fittings; Lithologic controls; Measured and calculated elastic properties; Mica schists; Micro probes; Mineral chemistries; Modal composition; Nature of seismic reflections; Outokumpu deep drill hole; Precambrian; Rock types; S-wave velocities; Seismic anisotropies; Seismic measurements; Shallow depths; Shear-wave splitting; Single-crystal properties; Strong anisotropies; Texture measurements; Velocity anisotropies; Wave trains; crustal structure; crystallography; drilling; elastic wave; granite; laboratory method; least squares method; mica; neutron diffraction; numerical model; P-wave; S-wave; schist; seismic anisotropy; seismic reflection; wave velocity; Minerals https://www.scopus.com/inward/record.uri?eid=2-s2.0-67349098374&doi=10.1016%2fj.pepi.2009.03.009&partnerID=40&md5=cf12770420787e4110327ad463a480d7 Cited by: 56; All Open Access, Green Open Access H. Kern K. Mengel K.W. Strauss T.I. Ivankina A.N. Nikitin I.T. Kukkonen article Liu2009126 The oxygen isotopic composition of carbonate in lakes has been used as a useful indicator in Palaeolimnological research, and has made some important contributions to our understanding of lacustrine systems. For modern lakes in arid or cold areas, however, there are few data available to test the effect of lake salinity and temperature on the oxygen isotopic composition of various carbonate sources such as ostracod, bulk carbonate, and fine-grained carbonate (< 60 μm). Here we examined the oxygen isotopic composition of ostracods, bulk carbonate, and fine-grained carbonates, as well as that of coexisting water from Lake Qinghai and the smaller surrounding lakes and ponds on the Qinghai-Tibet Plateau. Our investigation highlights three key effects. First, the oxygen isotopic composition of ostracods, bulk carbonate, and fine-grained carbonate in the lakes and ponds shows a clear response to lake water δ18O values, and these vary with water salinity. The relationship between lake water δ18O and salinity is not only dominated by the evaporation/freshwater input ratios, but is also controlled by the distance to the mouth of the major rivers supplying to the lake. Second, the ostracod, bulk carbonate, and fine-grained carbonate show similar isotopic change trends in the study area, and oxygen isotopic differences between ostracods and authigenic carbonate may be explained by the different water temperatures and very small 'vital offsets' of ostracods. Finally, the effect of water depth on temperature leads to increasing δ18O values in carbonates as water depth increases, both in benthic ostracods living on the lake bottom, as well as in bulk carbonate precipitated at the water surface. For arid, high-altitude Lake Qinghai, our results suggest that variations in the δ18O values of carbonate in Lake Qinghai are mainly controlled by the oxygen-isotope ratio of the lake water changing with water salinity. As a secondary effect, increasing water depth leads to cooler bottom and surface water, which may result in more positive δ18O values of ostracod and bulk carbonate. © 2009 Elsevier B.V. All rights reserved. Article 2009 English 00092541 10.1016/j.chemgeo.2009.08.004 Chemical Geology 268 126 – 136 1-2 Asia; China; Eurasia; Far East; Qinghai; Qinghai Lake; Ostracoda; arid environment; carbonate sediment; fine grained sediment; isotopic composition; lacustrine deposit; lake evolution; ostracod; oxygen isotope; salinity; water depth; water temperature https://www.scopus.com/inward/record.uri?eid=2-s2.0-70349548779&doi=10.1016%2fj.chemgeo.2009.08.004&partnerID=40&md5=7f3ed1b3dd29b2b08257ae15264e4910 Cited by: 79 Weiguo Liu Xiangzhong Li Ling Zhang ZhiSheng An Liming Xu article HortonJr.2009277 The 1766-m-deep Eyreville B core from the late Eocene Chesapeake Bay impact structure includes, in ascending order, a lower basement-derived section of schist and pegmatitic granite with impact breccia dikes, polymict impact breccias, and cataclas tic gneiss blocks overlain by suevites and clast-rich impact melt rocks, sand with an amphibolite block and lithic boulders, and a 275-m-thick granite slab overlain by crater-fill sediments and postimpact strata. Graphite-rich cataclasite marks a detachment fault atop the lower basement-derived section. Overlying impactites consist mainly of basement-derived clasts and impact melt particles, and coastalplain sediment clasts are underrepresented. Shocked quartz is common, and coesite and reidite are confirmed by Raman spectra. Silicate glasses have textures indicating immiscible melts at quench, and they are partly altered to smectite. Chrome spinel, baddeleyite, and corundum in silicate glass indicate high-temperature crystallization under silica undersaturation. Clast-rich impact melt rocks contain α- cristobalite and monoclinic tridymite. The impactites record an upward transition from slumped ground surge to melt-rich fallback from the ejecta plume. Basement-derived rocks include amphibolite-facies schists, greenschist(?)-facies quartz-feldspar gneiss blocks and subgreenschist-facies shale and siltstone clasts in polymict impact breccias, the amphibolite block, and the granite slab. The granite slab, underlying sand, and amphibolite block represent rock avalanches from inward collapse of unshocked bedrock around the transient crater rim. Gneissic and massive granites in the slab yield U-Pb sensitive high-resolution ion microprobe (SHRIMP) zircon dates of 615 ± 7 Ma and 254 ± 3 Ma, respectively. Postimpact heating was 7lt;~350 °C in the lower basementderived section based on undisturbed 40 Ar/ 39 Ar plateau ages of muscovite and &lt;~150 &lt;C in sand above the suevite based on 40 Ar/ 39 Ar age spectra of detrital microcline. © 2009 The Geological Society of America. 2009 English 00721077 10.1130/2009.2458(14) Special Paper of the Geological Society of America 458 Geological Society of America 277-316 U.S. Geological Survey, MS 926A, 12201 Sunrise Valley Drive, Reston, VA 20192, United States; U.S. Geological Survey, MS 956, 12201 Sunrise Valley Drive, Reston, VA 20192, United States; U.S. Geological Survey, MS 963, Denver Federal Center, Denver, CO 80225, United States; U.S. Geological Survey, MS 954, 12201 Sunrise Valley Drive, Reston, VA 20192, United States Buildings; Corundum; Feldspar; Glass; Granite; Lead alloys; Mica; Quartz; Silicate minerals; Structural geology; Tectonics; Textures; Zircon, Amphibolite facies; Chesapeake bay impact structures; Crystalline target rocks; Detachment fault; High temperature crystallization; Sensitive high-resolution ion microprobe; Shocked quartz; Undersaturation, Crystalline rocks, breccia; crystalline rock; crystallization; Eocene; granite; impact structure; impactite; marine sediment; SHRIMP dating, Chesapeake Bay; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-74949124057&doi=10.1130%2f2009.2458%2814%29&partnerID=40&md5=6074c29ddf5110532968a2d9be35b5f9 cited By 24 J.W. Horton Jr. M.J. Kunk H.E. Belkin J.N. Aleinikoff J.C. Jackson I.-M. Chou article HortonJr.2009277 The 1766-m-deep Eyreville B core from the late Eocene Chesapeake Bay impact structure includes, in ascending order, a lower basement-derived section of schist and pegmatitic granite with impact breccia dikes, polymict impact breccias, and cataclas tic gneiss blocks overlain by suevites and clast-rich impact melt rocks, sand with an amphibolite block and lithic boulders, and a 275-m-thick granite slab overlain by crater-fill sediments and postimpact strata. Graphite-rich cataclasite marks a detachment fault atop the lower basement-derived section. Overlying impactites consist mainly of basement-derived clasts and impact melt particles, and coastalplain sediment clasts are underrepresented. Shocked quartz is common, and coesite and reidite are confirmed by Raman spectra. Silicate glasses have textures indicating immiscible melts at quench, and they are partly altered to smectite. Chrome spinel, baddeleyite, and corundum in silicate glass indicate high-temperature crystallization under silica undersaturation. Clast-rich impact melt rocks contain α- cristobalite and monoclinic tridymite. The impactites record an upward transition from slumped ground surge to melt-rich fallback from the ejecta plume. Basement-derived rocks include amphibolite-facies schists, greenschist(?)-facies quartz-feldspar gneiss blocks and subgreenschist-facies shale and siltstone clasts in polymict impact breccias, the amphibolite block, and the granite slab. The granite slab, underlying sand, and amphibolite block represent rock avalanches from inward collapse of unshocked bedrock around the transient crater rim. Gneissic and massive granites in the slab yield U-Pb sensitive high-resolution ion microprobe (SHRIMP) zircon dates of 615 ± 7 Ma and 254 ± 3 Ma, respectively. Postimpact heating was 7lt;~350 °C in the lower basementderived section based on undisturbed 40 Ar/ 39 Ar plateau ages of muscovite and &lt;~150 &lt;C in sand above the suevite based on 40 Ar/ 39 Ar age spectra of detrital microcline. © 2009 The Geological Society of America. 2009 10.1130/2009.2458(14) Special Paper of the Geological Society of America 458 277-316 U.S. Geological Survey, MS 926A, 12201 Sunrise Valley Drive, Reston, VA 20192, United States; U.S. Geological Survey, MS 956, 12201 Sunrise Valley Drive, Reston, VA 20192, United States; U.S. Geological Survey, MS 963, Denver Federal Center, Denver, CO 80225, United States; U.S. Geological Survey, MS 954, 12201 Sunrise Valley Drive, Reston, VA 20192, United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-74949124057&doi=10.1130%2f2009.2458%2814%29&partnerID=40&md5=6074c29ddf5110532968a2d9be35b5f9 cited By 24 J.W. Horton Jr. M.J. Kunk H.E. Belkin J.N. Aleinikoff J.C. Jackson I.-M. Chou article Declercq2009559 The alteration or transformation of impact melt rock to clay minerals, particularly smectite, has been recognized in several impact structures (e.g., Ries, Chicxulub, Mjølnir). We studied the experimental alteration of two natural impact melt rocks from suevite clasts that were recovered from drill cores into the Chesapeake Bay impact structure and two synthetic glasses. These experiments were conducted at hydrothermal temperature (265 °C) in order to reproduce conditions found in meltbearing deposits in the first thousand years after deposition. The experimental results were compared to geochemical modeling (PHREEQC) of the same alteration and to original mineral assemblages in the natural melt rock samples. In the alteration experiments, clay minerals formed on the surfaces of the melt particles and as fine-grained suspended material. Authigenic expanding clay minerals (saponite and Ca-smectite) and vermiculite/chlorite (clinochlore) were identified in addition to analcime. Ferripyrophyllite was formed in three of four experiments. Comparable minerals were predicted in the PHREEQC modeling. A comparison between the phases formed in our experiments and those in the cores suggests that the natural alteration occurred under hydrothermal conditions similar to those reproduced in the experiment. © 2009 The Geological Society of America. 2009 10.1130/2009.2458(24) Special Paper of the Geological Society of America 458 559-569 Department of Geosciences, University of Oslo, P.O. Box 1047, Oslo, NO 316, Norway; Department of Geology and Geophysics, Louisiana State University, Baton Rouge, LA 70803, United States; U.S. Geological Survey, 926A National Center, Reston, VA 20192, United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-74949088037&doi=10.1130%2f2009.2458%2824%29&partnerID=40&md5=ef733bf9762a7e3aad0172fe8b93cf51 cited By 7 J. Declercq H. Dypvik P. Aagaard J. Jahren R.E. Ferrell Jr. J. Wright Horton Jr. article Declercq2009559 The alteration or transformation of impact melt rock to clay minerals, particularly smectite, has been recognized in several impact structures (e.g., Ries, Chicxulub, Mjølnir). We studied the experimental alteration of two natural impact melt rocks from suevite clasts that were recovered from drill cores into the Chesapeake Bay impact structure and two synthetic glasses. These experiments were conducted at hydrothermal temperature (265 °C) in order to reproduce conditions found in meltbearing deposits in the first thousand years after deposition. The experimental results were compared to geochemical modeling (PHREEQC) of the same alteration and to original mineral assemblages in the natural melt rock samples. In the alteration experiments, clay minerals formed on the surfaces of the melt particles and as fine-grained suspended material. Authigenic expanding clay minerals (saponite and Ca-smectite) and vermiculite/chlorite (clinochlore) were identified in addition to analcime. Ferripyrophyllite was formed in three of four experiments. Comparable minerals were predicted in the PHREEQC modeling. A comparison between the phases formed in our experiments and those in the cores suggests that the natural alteration occurred under hydrothermal conditions similar to those reproduced in the experiment. © 2009 The Geological Society of America. 2009 English 00721077 10.1130/2009.2458(24) Special Paper of the Geological Society of America 458 Geological Society of America 559-569 Department of Geosciences, University of Oslo, P.O. Box 1047, Oslo, NO 316, Norway; Department of Geology and Geophysics, Louisiana State University, Baton Rouge, LA 70803, United States; U.S. Geological Survey, 926A National Center, Reston, VA 20192, United States Chlorite minerals; Clay alteration; Core drilling; Infill drilling; Rocks; Zeolites, Chesapeake bay impact structures; Geochemical modeling; Hydrothermal conditions; Hydrothermal temperature; Impact structures; Mineral assemblage; Suspended material; Synthetic glass, Clay minerals, authigenic mineral; experimental study; hydrothermal activity; hydrothermal alteration; hydrothermal deposit; hydrothermal system; impact structure; numerical model; smectite; suevite, Chesapeake Bay; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-74949088037&doi=10.1130%2f2009.2458%2824%29&partnerID=40&md5=ef733bf9762a7e3aad0172fe8b93cf51 cited By 7 J. Declercq H. Dypvik P. Aagaard J. Jahren R.E. Ferrell Jr. J. Wright Horton Jr. article Xu2009235 The 5158-m-deep main borehole of the Chinese Continental Scientific Drilling Project (CCSD-MH) penetrated granitic gneisses, paragneisses, eclogites, retrograde eclogites, amphibolites and ultramafic rocks in the Sulu ultrahigh-pressure (UHP) metamorphic terrane, eastern China. The CCSD-MH consists of four petro-structural units separated by three SE-dipping ductile shear zones DFa (835-1280 m), DFb (2010-2280 m) and DFc (2920-3225 m), which are correspondent with the regional shear zones in the northern Sulu UHP supracrustal zone. Using the electron backscatter diffraction (EBSD) technique, we investigated the lattice-preferred orientations (LPOs) of omphacite, diopside and quartz in core samples from the CCSD-MH. Omphacite from eclogites and diopside from garnet pyroxenites display very strong LPOs, which are characterized by the maximum concentration of [001]-axes parallel to the lineation and (010)-poles normal to the foliation. Quartz in para- and granitic mylonites/gneisses from the shear zones DFa, DFb and DFc developed multiple slip systems. 40Ar/39Ar dating of biotite in para- and granitic gneisses from the CCSD-MH yields 223-202 Ma, which constrains the formation ages of the quartz high-temperature prism slip systems {m}<a> and {m}[c]. The asymmetric LPOs of omphacite, diopside, olivine and quartz with respect to the structural frame reveal three deformation phases in the Sulu terrane. In the Middle Triassic, the northward subduction of the Yangtze plate to depths > 100 km produced a top-to-the-south shear sense in LPOs of omphacite, diopside and olivine, and a nearly N-S-striking foliation and a subhorizontal N-S-trending lineation in eclogites and ultramafic rocks. In the Late Triassic, the UHP rocks were exhumed to the lower crust and quartz developed high-temperature slip systems with a top-to-the-NW shear sense, which is consistent with the regional SE-dipping foliation and SE-plunging lineation in the ductile shear zones. In the Cretaceous the UHP rocks were exhumed to the middle crust when the migmatization and granitic intrusion formed a NE-striking antiform structure. As a result, the activation of quartz low-temperature basal slip (0001)<a> is characterized by a top-to-the-SE shear sense in the south, but a top-to-the-NW shear sense in the north. © 2009 Elsevier B.V. All rights reserved. Article 2009 English 00401951 10.1016/j.tecto.2009.02.041 Tectonophysics 475 235 – 250 2 Asia; China; Eurasia; Far East; Sulu Belt; Yangtze Platform; Drilling; Electron diffraction; Garnets; Housing; Kinematics; Metal vapor lamps; Mica; Olivine; Oxide minerals; Quartz; Rocks; Shear deformation; Silicate minerals; Spontaneous emission; Structural design; Structural geology; Tectonics; X ray powder diffraction; Ar dating; Continental subduction; Exhumation; Lattice-preferred orientation; Sulu terrane; amphibolite; asymmetry; borehole geophysics; Chinese Continental Scientific Drilling Project; deformation; dip-slip fault; eclogite; exhumation; gneiss; kinematics; lineation; petrofabric; preferred orientation; regional metamorphism; retrograde metamorphism; shear zone; subduction; tectonic evolution; tectonic setting; ultrahigh pressure metamorphism; ultramafic rock; Metamorphic rocks https://www.scopus.com/inward/record.uri?eid=2-s2.0-70349112744&doi=10.1016%2fj.tecto.2009.02.041&partnerID=40&md5=4e22507c8414552e4335544254003ee0 Cited by: 32 Zhiqin Xu Qin Wang Zhemin Tang Fangyuan Chen article Boettcher2009 [1] With twelve years of seismic data from TauTona Gold Mine, South Africa, we show that mining-induced earthquakes follow the Gutenberg-Richter relation with no scale break down to the completeness level of the catalog, at moment magnitude Mw -1.3. Events recorded during relatively quiet hours in 2006 indicate that catalog detection limitations, not earthquake source physics, controlled the previously reported minimum magnitude in this mine. Within the Natural Earthquake Laboratory in South African Mines (NELSAM) experiment's dense seismic array, earthquakes that exhibit shear failure at magnitudes as small as Mw -3.9 are observed, but we find no evidence that Mw -3.9 represents the minimum magnitude. In contrast to previous work, our results imply small nucleation zones and that earthquake processes in the mine can readily be scaled to those in either laboratory experiments or natural faults. 2009 English 00948276 10.1029/2009GL038080 Geophysical Research Letters 36 L10307 U.S. Geological Survey, MS 977, 345 Middlefield Road, Menlo Park, CA 94025, United States; Department of Earth Sciences, University of New Hampshire, 24 Nesmith Hall, 131 Main Street, Durham, NH 03824, United States 10 Break down; Earthquake process; Earthquake source; Laboratory experiments; Lower limits; Moment magnitudes; Natural earthquake; Nucleation zone; Seismic arrays; Seismic data; Shear failure; South Africa, Mines; Mining, Earthquakes, earthquake; gold mine; mining-induced seismicity; nucleation; seismic data; spatial distribution, Africa; South Africa; Southern Africa; Sub-Saharan Africa https://www.scopus.com/inward/record.uri?eid=2-s2.0-67651121531&doi=10.1029%2f2009GL038080&partnerID=40&md5=51be8d817659d454d8fa8bffe345ee78 cited By 47 M.S. Boettcher A. McGarr M. Johnston article Keller2008621 2008 10.1016/j.epsl.2007.12.025 Earth and Planetary Science Letters 269 621-629 Geosciences, Princeton University, Princeton, NJ 08540, United States; Geological Institute, University of Neuchatel, Neuchatel, CH-2007, Switzerland; Baum and Associates LLC, 53 Inwood Heights Dr. N, San Antonio, TX 78248, United States; Institute for Mineralogy and Geochemistry, University of Karlsruhe, 76128 Karlsruhe, Germany 3-4 https://www.scopus.com/inward/record.uri?eid=2-s2.0-43249128540&doi=10.1016%2fj.epsl.2007.12.025&partnerID=40&md5=e4f5c1d11590b6eacc8fa617f6583acf cited By 13 G. Keller T. Adatte G. Baum Z. Berner article demske2008raw2 2008 GFZ Data Services Dieter Demske Georg Heumann Wojciech Granoszewski Malgorzata Nita Kazimiera Mamakowa Pavel Tarasov Hedi Oberhänsli article demske2008raw1 2008 GFZ Data Services Dieter Demske Georg Heumann Wojciech Granoszewski Malgorzata Nita Kazimiera Mamakowa Pavel Tarasov Hedi Oberhänsli article Tretner200828 During the Unzen conduit drilling project USDP-4, the gas phase dissolved in the drill mud was continuously analyzed. Starting from the volcano's north flank an almost complete gas profile was achieved to the final depth of 1995.75 m in July 2004. Limitations were given due to the extremely difficult drilling conditions. The highly fractured rock formation led to loss of drill mud circulation in the shallow parts of the drill hole. Significant fluid inflow horizons did not occur above 800 m (drill string length). Starting from that depth on, invading fluids were detected with the real-time gas monitoring system. Major variations in the mud gas composition occurred only below a depth of 1000 m. Of major importance are fluid inflow zones with high 3He/4He at depths of 1555 m (7.3 RA), 1755.5 m (7.48 RA) and 1977.4 m (6.21 RA). These values indicate a significant influence of fluids with mantle signature. Furthermore, enhanced methane, radon and helium concentrations were also detected at specific depth. These detected major fluid- and gas inflow horizons may be able to explain magmatic degassing processes, related to the Unzen's eruption mechanism. This is generally true for the main fluid inflow zones and especially for the detected inflows at 1555 m, 1755.5 m and 1977.4 m. Furthermore, a correlation between lithology and gas composition was observed. Higher H2S concentrations were detected while drilling in pyrite-rich rocks. Cracks and fissures as well as lithological changes are often correlated with increasing amounts of gas. Trends with depth, from a minor to a more magmatic influenced regime were observed together with a change in hydrothermal alteration of the surrounding rock. This corresponds with the magmatic conduit zone which was penetrated at a depth of 1600 m, and supports the model of a high influence of hydrothermal fluid, accelerating cooling and mineral alteration. © 2008 Elsevier B.V. All rights reserved. 2008 English 03770273 10.1016/j.jvolgeores.2008.03.031 Journal of Volcanology and Geothermal Research 175 28-34 GeoForschungsZentrum Potsdam (GFZ), Potsdam, Germany; Volcano Research Center, Earthquake Research Institute, University of Tokyo, Japan; Shimabara Observatory, Institute of Seismology and Volcanology, Kyushu University, Shimabara, Japan 1-2 Dissolution; Drilling; Drills; Gas detectors; Gases; Landforms; Mud logging; Volcanoes; Well drilling, conduit drilling; continuous gas monitoring; Drill holes; Drill strings; Fractured rocks; Gas compositions; Gas monitoring; Gas-phase; He isotopes; Mud circulation; Unzen; USDP-4, Natural gas well drilling, cooling; degassing; drilling; helium isotope; hydrothermal alteration; hydrothermal fluid; mineral alteration; real time; volcanic eruption; well logging, Asia; Eurasia; Far East; Japan; Kyushu; Nagasaki [Kyushu]; Unzen Volcano https://www.scopus.com/inward/record.uri?eid=2-s2.0-50049109149&doi=10.1016%2fj.jvolgeores.2008.03.031&partnerID=40&md5=dfc3904dc57a51d009d6f0a452a97f08 cited By 14 A. Tretner M. Zimmer J. Erzinger S. Nakada M. Saito article Li2008 Highly damaged rocks within the San Andreas fault zone at Parkfield form a low-velocity waveguide for seismic waves, giving rise to fault-guided waves. Prominent fault-guided waves have been observed at the San Andreas Fault Observatory at Depth (SAFOD) site, including a surface array across the fault zone and a borehole seismograph placed in the SAFOD well at a depth of ∼2.7 km below ground. The resulting observations are modeled here using 3-D finite-difference methods. To fit the amplitude, frequency, and travel-time characteristics of the data, the models require a downward tapering, 30-40-m wide faultcore embedded in a 100-200-m wide jacket. Compared with the intact wall rocks, the core velocities are reduced by ∼40% and jacket velocities by ∼25%. Based on the depths of earthquakes generating guided waves, we estimate that the low-velocity waveguide along the fault at SAFOD extends at least to depths of ∼7 km, more than twice the depth reported in pervious studies. Copyright 2008 by the American Geophysical Union. 2008 English 00948276 10.1029/2007GL032924 Geophysical Research Letters 35 Department of Earth Sciences, University of Southern California, Los Angeles, CA 90089, United States; Institute of Earth Science and Engineering, University of Auckland, Auckland 1142, New Zealand 8 Seismology; Waveguides, American Geophysical Union; Bore hole; Fault zones; Finite difference (FD); Guided waves; Low velocities; Parkfield; San Andreas Fault (SAF); Surface array; Travel time, Guided electromagnetic wave propagation, fault zone; finite difference method; San Andreas Fault; seismic data; seismic wave; seismograph; three-dimensional modeling; wave velocity, California; North America; Parkfield; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-48249130104&doi=10.1029%2f2007GL032924&partnerID=40&md5=cf9b82fdb85e9aca6067ab4146aa0931 cited By 53 Y.-G. Li article Paquay2008 Morgan argues that excursions in the marine Os record are of little value for estimating impactor size. This claim is based on computer simulations of the formation of the Chicxulub crater and distribution of the ejecta, which are difficult to validate. More important, by narrowly focusing on the Cretaceous-Tertiary event Morgan's comment misses the broader implications of our study. 2008 10.1126/science.1159234 Science 321 1158b Department of Geology and Geophysics, University of Hawaii, Honolulu, HI 96822-2225, United States; Department of Geology and Geophysics, Indian Institute of Technology, Kharagpur 721302, India; Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, United States 5893 https://www.scopus.com/inward/record.uri?eid=2-s2.0-50649089574&doi=10.1126%2fscience.1159234&partnerID=40&md5=68561a1b6de04649562f469c91984438 cited By 1 F.S. Paquay G.E. Ravizza T.K. Dalai B. Peucker-Ehrenbrink article Horálek2008455 We summarise the results of seismological studies related to triggering mechanisms, driving forces and source processes of the West Bohemia/ Vogtland earthquake swarms with the aim to disclose the role of crustal fluids in the preparation, triggering and governing of the swarms. We present basic characteristics distinguishing earthquake swarms from tectonic mainshock-aftershock sequences and introduce existing earthquakes swarm models. From the statistical characteristics and time-space distribution of the foci we infer that self-organization is a peculiarity of West Bohemia/Vogtland swarms. We discuss possible causes of the foci migration in these swarms from the viewpoint of co-seismic and/or post-seismic stress changes and diffusion of the pressurized fluids, and we summarize hitherto published models of triggering the 2000-swarm. Attention is paid to the source mechanisms, particularly to their non-shear components. We consider possible causes of different source mechanisms of the 1997-and 2000-swarms and infer that pure shear processes controlled solely by the regional tectonic stress prevail in them, and that additional tensile forces may appear only at unfavourably oriented faults. On data from the fluid injection experiment at the HDR site Soultz (Alsace), we also show that earthquakes triggered by fluids can represent purely shear processes. Thus we conclude that increased pore pressure of crustal fluids in the region plays a key role in bringing the faults from the subcritical to critical state. The swarm activities are mainly driven by stress changes due to co-seismic and post-seismic slips, which considerably depend on the frictional conditions at the fault; crustal fluids keep the fault in a critical state. An open question still remains the cause of the repeatedly observed almost simultaneous occurrence of seismic activity in different focal zones in a wider area of West Bohemia/Vogtland. The analysis of the space-time relations of seismicity in the area between 1991 and 2007 revealed that during a significant part of this time span the seismicity was switching among distant focal zones. This indicates a common triggering force which might be the effect of an increase of crustal-fluid pore-pressure affecting a wider epicentral region. © Institute of Geophysics of the ASCR, v.v.i 2008. Review 2008 English 00393169 10.1007/s11200-008-0032-0 Studia Geophysica et Geodaetica 52 455 – 478 4 aftershock; crustal structure; earthquake epicenter; earthquake swarm; fluid; fluid injection; pore pressure; seismic source; seismicity; trigger mechanism https://www.scopus.com/inward/record.uri?eid=2-s2.0-57549113662&doi=10.1007%2fs11200-008-0032-0&partnerID=40&md5=a52f3b3acdc25ff9da58e13f4d7b779c Cited by: 68 J. Horálek T. Fischer article Cheng200855 Article 2008 Acta Geologica Sinica (English Edition) 82 55 – 64 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-44249086927&partnerID=40&md5=d3346a3cea3f72a2a018f3135d8c9184 Cited by: 23 Rihui Cheng Guodong Wang Pujun Wang article Huang200860 2008 English 18168957 10.2204/lodp.sd.6.11.2008 Scientific Drilling 60-61 Research Center for Tibetan Plateau Geology, China University of Geosciences, Xueyuan Road 29, Haidian District 100083 Beijing, China 6 https://www.scopus.com/inward/record.uri?eid=2-s2.0-78651556077&doi=10.2204%2flodp.sd.6.11.2008&partnerID=40&md5=7389312a56538fd209802c42b30dc079 cited By 4 Y. Huang C. Wang article demske2008raw5 2008 GFZ Data Services Dieter Demske Georg Heumann Wojciech Granoszewski Malgorzata Nita Kazimiera Mamakowa Pavel Tarasov Hedi Oberhänsli article demske2008raw4 2008 GFZ Data Services Dieter Demske Georg Heumann Wojciech Granoszewski Malgorzata Nita Kazimiera Mamakowa Pavel Tarasov Hedi Oberhänsli article Watanabe200882 Permeability measurement was made on five rock samples from USDP-4 cores. Rock samples were collected from the conduit zone and its country rock. One sample (C14-1-1) is considered as a part of the feeder dyke for the 1991-1995 eruption. The transient pulse method was employed under confining pressure up to 50 MPa. Compressional wave velocity was measured along with permeability. The measured permeability ranges from 10- 19 to 10- 17 m2 at the atmospheric pressure, and is as low as that reported for tight rocks such as granite. The permeability decreases with increasing confining pressure, while the compressional wave velocity increases. Assuming that pores are parallel elliptical tubes, the pressure dependence of permeability requires aspect ratio of 10- 4-10- 2 at the atmospheric pressure. The pore aperture is estimated to be less than 1 μm. The estimated aspect ratio and pore aperture suggest that connectivity of pores is maintained by narrow cracks. The existence of cracks is supported by the pressure dependence of compressional wave velocity. Narrow cracks (&lt; 1 μm) are observed in dyke samples, and they must have been created after solidification. Dyke samples do not provide us information of pore structures during degassing, since exsolved gas has mostly escaped and pores governing the gas permeable flow should have been lost. Both dyke and country rock samples provide us information of materials around ascending magma. Although the measured small-scale permeability cannot be directly applied to geological-scale processes, it gives constrains on studies of large-scale permeability. © 2008 Elsevier B.V. All rights reserved. 2008 English 03770273 10.1016/j.jvolgeores.2008.03.021 Journal of Volcanology and Geothermal Research 175 82-90 Department of Earth Sciences, University of Toyama, Gofuku 3190, Toyama, 930-8555, Japan; Earthquake Research Institute, University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo, 113-0032, Japan 1-2 Capillarity; Liquids; Rocks; Solids, Compressional wave velocities; Confining pressures; crack; Drill holes; drilled core; permeability; Permeability measurements; pore structure; Rock samples; Transient pulse; Unzen volcano, Rock drilling, atmospheric pressure; country rock; crack; degassing; dike; drilling; gas flow; granite; permeability; solidification; volcanic eruption; wave velocity, Asia; Eurasia; Far East; Japan; Kyushu; Nagasaki [Kyushu]; Unzen Volcano https://www.scopus.com/inward/record.uri?eid=2-s2.0-50049093966&doi=10.1016%2fj.jvolgeores.2008.03.021&partnerID=40&md5=8678980b0549b4ed3eb0490147613467 cited By 12 T. Watanabe Y. Shimizu S. Noguchi S. Nakada article Schmidt2008203 The Qinling-Dabie-Sulu orogenic belt in eastern China is one of the largest ultrahigh-pressure (UHP) terranes worldwide. Mineral Sm-Nd- and zircon U-Pb dating has been widely used to reveal the metamorphic history of this collisional orogen. However, the exact timing of the UHP metamorphic event(s) remains controversial and ages ranging from 245 Ma to 220 Ma have been suggested. We present high precision garnet-cpx Lu-Hf ages for six eclogites from the Dabie and Sulu areas. All ages fall in a narrow range between 219.6 and 224.4 Ma. Five samples define a mean age of 223.0 ± 0.9 Ma and one sample yields a slightly younger age of 219.6 ± 1.4 Ma. This very tight age range is particularly remarkable considering the large regional distribution of sample localities (on the order of 100 km at the time of UHP metamorphism) and the wide variety of garnet and eclogite chemical compositions represented. Two samples yield Sm-Nd ages that are indistinguishable from their Lu-Hf ages, albeit with larger uncertainties. The identical ages of eclogites from both the Dabie and the Sulu region emphasize their close genetic relationship and similar metamorphic histories. The Lu-Hf results appear to date a punctuated event of garnet growth. Alternatively, the Lu-Hf garnet ages may represent the onset of rapid, contemporaneous uplift and subsequent cooling. However, trace element zoning of Lu and Hf is still preserved in garnet porphyroblasts, even in those with a homogeneous major element distribution. Thus, complete re-equilibration of the Lu-Hf system during peak-temperature conditions probably did not occur. The garnet forming event can be placed toward the final stage of the UHP metamorphism, in agreement with some published U-Pb zircon ages. A possible trigger for this short-lived and widespread mineral growth episode may have been a fluid that became available at that stage of the metamorphic history. Although HREE-depleted patterns of older zircon grains may indicate the presence of an older generation of garnet, complete eclogitisation may have been inhibited during the major part of the prograde P-T path due to dry conditions during most of the UHP metamorphism. The uniform Lu-Hf (and Sm-Nd) ages of all investigated Dabie and Sulu eclogites suggest that garnet growth and thus possibly fluid availability were limited to a short time interval over a remarkably large regional scale. © 2008 Elsevier B.V. All rights reserved. Article 2008 English 0012821X 10.1016/j.epsl.2008.06.036 Earth and Planetary Science Letters 273 203 – 213 1-2 Asia; China; Dabie-Sulu Belt; Eurasia; Far East; Chemical elements; Garnets; Geochronology; Hafnium; History; Land use; Lead alloys; Lutetium; Metamorphic rocks; Mineralogy; Minerals; Mining; Neodymium; Silica; Trace elements; Zircon; Chemical compositions; Dry conditions; Eastern China; eclogite; Eclogites; eclogitisation; Genetic relationships; HF systems; High-precision; Lu-Hf geochronology; Major elements; Mineral growth; Orogenic belts; Porphyroblasts; Re-equilibration; Regional distribution; Regional scales; Short time; Sm-Nd geochronology; Subsequent cooling; Temperature conditions; U-Pb dating; U-Pb zircon; UHP metamorphism; ultrahigh-pressure; chemical composition; eclogite; garnet; geochronology; hafnium; lutetium; orogenic belt; P-T-t path; terrane; ultrahigh pressure metamorphism; Silicate minerals https://www.scopus.com/inward/record.uri?eid=2-s2.0-49249128039&doi=10.1016%2fj.epsl.2008.06.036&partnerID=40&md5=7c3f5a19461637da2694cb9cc704e6aa Cited by: 73; All Open Access, Green Open Access, Hybrid Gold Open Access Alexander Schmidt Stefan Weyer Klaus Mezger Erik E. Scherer Yilin Xiao Jochen Hoefs Gerhard P. Brey article Niu2008204 Measuring stress changes within seismically active fault zones has been a long-sought goal of seismology. One approach is to exploit the stress dependence of seismic wave velocity, and we have investigated this in an active source cross-well experiment at the San Andreas Fault Observatory at Depth (SAFOD) drill site. Here we show that stress changes are indeed measurable using this technique. Over a two-month period, we observed an excellent anti-correlation between changes in the time required for a shear wave to travel through the rock along a fixed pathway (a few microseconds) and variations in barometric pressure. We also observed two large excursions in the travel-time data that are coincident with two earthquakes that are among those predicted to produce the largest coseismic stress changes at SAFOD. The two excursions started approximately 10 and 2 hours before the events, respectively, suggesting that they may be related to pre-rupture stress induced changes in crack properties, as observed in early laboratory studies. ©2008 Macmillan Publishers Limited. All rights reserved. 2008 English 00280836 10.1038/nature07111 Nature 454 Nature Publishing Group 204-208 Department of Earth Science, MS-126, Rice University, 6100 Main Street, Houston, TX 77005, United States; Department of Terrestrial Magnetism, Carnegie Institution of Washington, 5241 Broad Branch Road, NW, Washington, DC 20015, United States; Earth Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, United States 7201 crack; earthquake; fault zone; measurement method; monitoring; rupture; seismic velocity; seismic wave, article; earthquake; environmental monitoring; measurement; pressure; priority journal; rock; stress, California; North America; San Andreas; San Andreas Fault Zone; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-47049108874&doi=10.1038%2fnature07111&partnerID=40&md5=d7b380346e97976c0cb0492ce90e8e88 cited By 219 F. Niu P.G. Silver T.M. Daley X. Cheng E.L. Majer article Wang20089 To obtain the global environmental and climatic records is going to be the aim of the international scientific drilling projects. As a paradigm of greenhouse climate in the geological history, the Cretaceous provides significant records of the global climate changes under the condition of greenhouse climate. But currently, the international scientific drilling programs on the Cretaceous have been focusing on marine sediments; in contrast, no terrestrial records have been recovered by any scientific program. Newly completed SK I and SK II drilling located at the northern part of the Songliao Basin are supposed to be an important breakthrough in this domain. After more than one year effort, the drilling project has been finished, and 2485.89 in of the cores have been obtained, with a high recovery ratio of 96.46%, and that is the longest and continuous Cretaceous terrestrial core all over the world. A number of important investigations and achievement on the cores from SK I and SK II have been carried out. One of the most significant contributions of this program is to get records with a resolution of ten thousand year by the centimeter-grade sampling and analysis, instead of the traditional records on million years of timescale, and hopefully, its research can provide an important reference to solve currently global warming. Combined with raw data and upcoming results for the core, an integrated accomplishment of the scientific can be made in ten profiles such as biostratigraphy, chemostratigraphy, magnetostratigraphy and geomicrobiology and so on. The preliminary progress has been achieved on sedimentology, organic geochemistry, cyclostratigraphy, paleolimnology, geomicrobiology and reconstruction of Pco'2. All the cores will be preserved in professional storeroom after being cut for our researches, and scientists all over the world are highly welcome. The follow-up the SK II drilling program has also been selected as one of the candidate programs of ICDP (International Continental Drilling Project). 2008 Chinese 10009515 Acta Geologica Sinica (English Edition) 82 Science Press 9-20 School of Earth Sciences and Resources, China University of Geosciences, Beijing 100083, China; Institute of Exploration and Development, Daqing Oilfield Company Ltd., Daqing 163712, China; School of Earth Sciences, Jilin University, Changchun 130061, China; Exploration Company of Daqing Oil Field Company Ltd., Daqing 163453, China; School of Engineering, China University of Geosciences, Beijing 100083, China 1 biostratigraphy; chemostratigraphy; climate change; Cretaceous; cyclostratigraphy; Deep Sea Drilling Project; geomicrobiology; greenhouse gas; magnetostratigraphy; marine sediment; paleoclimate; paleoenvironment; reconstruction; sediment core, Asia; China; Eurasia; Far East; Songliao Basin https://www.scopus.com/inward/record.uri?eid=2-s2.0-44249088343&partnerID=40&md5=9b8fbde19d4555f96edf6533414c7501 cited By 36 C. Wang Z. Feng H. Wu P. Wang F. Kong Y. Ren G. Yang X. Wan Y. Huang S. Zhang article Urrutia-Fucugauchi2008248 The Chicxulub crater has attracted considerable attention as one of the largest terrestrial impact structures and its association with the Cretaceous/Palaeogene boundary. Analyses of stable isotopes and magnetostratigraphic results for the Paleocene carbonate sequence in the Santa Elena borehole are used to investigate the post-impact sequence and estimate the age of basal sediments in the southern crater sector. Studies of impact ejecta and cover sediments and modelling of post-impact processes suggest erosion effects due to seawater back surge, block slumping and partial rim collapse of post-impact crater modification. Correlation of stable isotope patterns with the global pattern for marine carbonate sediments provides a stratigraphic framework for the basal Paleocene carbonates. Magnetic polarity constrains correlation of stable isotope variations with the reference Cenozoic isotopic data suggest that the first 17 m above the breccia-carbonate contact represents about 2.5 Ma. The stable isotope data suggest a gap of less than 0.1 Ma, whereas the magnetic polarity data (absence of reverse-polarity samples above impact breccia contact) suggest a gap up to 0.25 Ma. 2008 Current Science 95 248-252 Laboratorio de Paleomagnetismo Y Paleoambientes, Instituto de Geofisica, Ciudad Universitaria, Circuito Exterior S/N, Coyoacan, DF 04510, Mexico 2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-47949100674&partnerID=40&md5=e9a656aac3631cde4da80f3a5ce665b5 cited By 12 J. Urrutia-Fucugauchi L. Pérez-Cruz article Grieve2008855 The structural, topographic and other characteristics of the Vredefort, Sudbury, and Chicxulub impact structures are described. Assuming that the structures originally had the same morphology, the observations/ interpretations for each structure are compared and extended to the other structures. This does not result in any major inconsistencies but requires that the observations be scaled spatially. In the case of Vredefort and Sudbury, this is accomplished by scaling the outer limit of particular shock metamorphic features. In the case of Chicxulub, scaling requires a reasoned assumption as to the formation mechanism of an interior peak ring. The observations/interpretations are then used to construct an integrated, empirical kinematic model for a terrestrial peak-ring basin. The major attributes of the model include: a set of outward-directed thrusts in the parautochthonous rocks of the outermost environs of the crater floor, some of which are pre-existing structures that have been reactivated during transient cavity formation; inward-directed motions along the same outermost structures and along a set of structures, at intermediate radial distances, during transient cavity collapse; structural uplift in the center followed by a final set of radially outward-directed thrusts at the outer edges of the structural uplift, during uplift collapse. The rock displacements on the intermediate, inward and innermost, outward sets of structures are consistent with the assumption that a peak ring will result from the convergence of the collapse of the transient cavity rim area and the collapse of the structural uplift. © The Meteoritical Society, 2008. 2008 10.1111/j.1945-5100.2008.tb01086.x Meteoritics and Planetary Science 43 855-882 Earth Sciences Sector, Natural Resources Canada, Ottawa, ON K1A 0E4, Canada; Humboldt Universität zu Berlin, Museum für Naturkunde, D-10115 Berlin, Germany; Department of Earth Science and Engineering, Imperial College London, London SW7 2AZ, United Kingdom 5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-51449087806&doi=10.1111%2fj.1945-5100.2008.tb01086.x&partnerID=40&md5=c8f8de471d99d6e5d5f4bdf185a49d68 cited By 72 R.A.F. Grieve W.U. Reimold J. Morgan U. Riller M. Pilkington article Stachura-Suchoples2008171 Pliocaenicus seczkinae Stachura-Suchoples, Genkal & Khursevich, sp. nov. was described from the phytoplankton samples and surface bottom deposits of Lake El'gygytgyn located in central Chukotka, NE Russia. The species is distinguished from the nominate variety of P. costatus mainly by the different structure of the valve face fultoportulae, which open externally with distinct short tubes and are flanked by two satellite pores. The tubes are located in small depressions within the radial rows of areolae. These observations have important implications for the entire genus, as up until now all known Pliocaenicus species had external fultoportulae openings lacking tubuli. Pliocaenicus seczkinae is the second known species of the genus Pliocaenicus to be found in modern populations. © 2008 Taylor & Francis Group, LLC. 2008 English 0269249X 10.1080/0269249X.2008.9705745 Diatom Research 23 171-184 Alfred-Wegener Institute for Polar and Marine Research, Telegrafenberg A 43, Potsdam, D-14473, Germany; I. D. Papanin Institute of Biology of Inland Waters, Russian Academy of Sciences, Settle of Borok, Nekouzsky district, Yaroslavl Region, 152742, Russian Federation; Institute of Geochemistry and Geophysics, National Academy of Sciences of Belarus, 7 Kuprevich street, Minsk, 220141, Belarus 1 diatom; morphology; phytoplankton; taxonomy, Chukchi; Elgygytgyn Lake; Eurasia; Russian Federation, Pliocaenicus; Pliocaenicus costatus https://www.scopus.com/inward/record.uri?eid=2-s2.0-43549101141&doi=10.1080%2f0269249X.2008.9705745&partnerID=40&md5=12dfaf0277ef15ce5951f7448ad4f243 cited By 10 K. Stachura-Suchoples S. Genkal G. Khursevich article Ikeda200813 The objective of the Unzen Scientific Drilling Project (USDP) is not only to reveal the structure and eruption history of the Unzen volcano but also to clarify the ascent and degassing mechanisms of the magma conduit. Conduit drilling (USDP-4) was conducted in 2004, which targeted the magma conduit for the 1990-95 eruption. The total drilled length of USDP-4 was 1995.75 m. Geophysical well logging, including resistivity, gamma-ray, spontaneous potential, sonic-wave velocity, density, neutron porosity, and Fullbore Formation MicroImager (FMI), was conducted at each drilling stage. Variations in the physical properties of the rocks were revealed by the well-log data, which correlated with not only large-scale formation boundaries but also small-scale changes in lithology. Such variations were evident in the lava dike, pyroclastic rocks, and breccias over depth intervals ranging from 1 to 40 m. These data support previous models for structure of the lava conduit, in that they indicate the existence of alternating layers of high-resistivity and high P-wave velocity rocks corresponding to the lava dikes, in proximity to narrower zones exhibiting high porosity, low resistivity, and low P-wave velocity. These narrow, low-porosity zones are presumably higher in permeability than the adjacent rocks and may form preferential conduits for degassing during magma ascent. © 2008 Elsevier B.V. 2008 English 03770273 10.1016/j.jvolgeores.2008.03.036 Journal of Volcanology and Geothermal Research 175 13-19 Faculty of Science, Hokkaido University, North-10 West-8, Kita-ku, Sapporo, Hokkaido, 060-0810, Japan; Japan Metals and Chemicals Co., Ltd., 101-1 Ukai Takizawa-mura, Iwate, 020-0172, Japan; National Research Institute for Earth Science and Disaster Prevention, 3-1 Tennodai, Tsukuba, Ibaraki, 305-0006, Japan; U.S. Geological Survey, 345 Middlefield Rd, Menlo Park, CA 94025, United States 1-2 Acoustic logging; Acoustic wave velocity; Degassing; Drilling; Forestry; Gamma rays; Harvesting; Human computer interaction; Hydraulic structures; Levees; Lithology; Logging (forestry); Neutron logging; Oil well logging; Porosity; Rock drilling; Rocks; Scale (deposits); Spontaneous potential logging; Structural geology, Alternating layers; Conduit structure; Data support; High porosity; Log data; Low resistivity; Magma ascent; Neutron porosity; P-wave velocities; Physical Properties; Pyroclastic rocks; Rock properties; Scale formation; Scientific drilling; Spontaneous potential; Unzen volcano; Wave velocities; Well logging, Well drilling, degassing; drilling; lava; lithology; magma; permeability; rock property; volcanic eruption; wave velocity; well logging, Corrosion; Degassing; Deposits; Drilling; Hydraulic Structures; Logging; Porosity; Velocity, Asia; Eurasia; Far East; Japan; Kyushu; Nagasaki [Kyushu]; Unzen Volcano https://www.scopus.com/inward/record.uri?eid=2-s2.0-50049126633&doi=10.1016%2fj.jvolgeores.2008.03.036&partnerID=40&md5=288963c217fb5646821f0fd13ee360e3 cited By 18 R. Ikeda T. Kajiwara K. Omura S. Hickman article Botcharnikov20081687 Crystallization experiments using a hydrous ferrobasalt as starting material, conducted at 200 MPa, 940-1200°C, at a wide range of water activities (0.1-1) and redox conditions (QFM - 3 to QFM + 4, where QFM is the quartz-fayalite-magnetite oxygen buffer), show that H2O influences significantly the differentiation history of ferrobasaltic magmas. A combination of our data with published experiments on dry ferrobasalt at 1 atm provides an extensive experimental database for modeling and quantifying crystallization and differentiation processes within a typical Fe-rich tholeiitic system under both dry and hydrous conditions. The addition of H2O decreases liquidus temperatures and changes significantly the proportions, temperature range and sequence of crystallizing mineral phases. The dry liquidus is at about 1170°C whereas the liquidus for H2O-saturated melts is at ∼1060°C. The main phases crystallizing from H2O-bearing ferrobasalt at the investigated conditions are olivine (OL), clinopyroxene (CPX), plagioclase (PL), magnetite (MT), hematite (HM), ilmenite (ILM) and amphibole (AM). The phase assemblage is similar to that of the dry system except for the presence of HM at extremely oxidizing conditions and AM at low temperatures (&lt; 950°C) and H2O-saturated conditions. The important observation made in this study is that the stability of Fe-Ti-oxides, and in particular MT, as well as the simultaneous coprecipitation of MT and ILM, are almost independent of the activity of H2O (a H2O) in the system, whereas the liquidus temperatures of the silicate minerals are dramatically depressed by increasing a H2O. The stabilities of oxides are controlled mainly by the redox conditions prevailing in the system. The most pronounced effect of a H2O on the liquidus temperatures of silicates is observed for PL, which shows a considerable delay in crystallization with progressive magma differentiation. Early crystallization of Fe-Ti-oxides in H2O-bearing ferrobasaltic compositions precludes any significant Fe enrichment during differentiation. As Fe enrichment is a characteristic feature of the Skaergaard intrusion, it implies that the Skaergaard parental magma did not contain considerable amounts of water. On the other hand, our experiments indicate that the differentiation of some ferrobasaltic series from the Columbia River flood basalt province might have occurred in magmatic systems containing significant amounts of volatiles (∼0.5-3 wt % H2O). © The Author 2008. Published by Oxford University Press. All rights reserved. 2008 English 00223530 10.1093/petrology/egn043 Journal of Petrology 49 1687-1727 Institut für Mineralogie, Leibniz Universität Hannover, Callinstr. 3, D-30167 Hannover, Germany 9 crystallization; differentiation; experimental study; flood basalt; hydrothermal system; magma; modeling; precipitation (chemistry); redox conditions; silicate mineral, Arctic; Columbia River; Greenland; North America; Skaergaard Intrusion https://www.scopus.com/inward/record.uri?eid=2-s2.0-53349116865&doi=10.1093%2fpetrology%2fegn043&partnerID=40&md5=ec7e9202baa46bea20e9b83bfe2aaced cited By 152 R.E. Botcharnikov R.R. Almeev J. Koepke F. Holtz article Schwamborn200855 Late Quaternary sediments in a permafrost environment recovered from the Elgygytgyn Impact Crater were studied to determine regional palaeoenvironmental variability and infer past water-level changes of the crater lake. Stratigraphic analysis of a 5m long permafrost core is based on various lithological (grain size, total organic carbon, magnetic susceptibility) and hydrochemical (oxygen isotope composition, major cation content) properties and pore ice content. The results show that alluvial sediments accumulated on top of cryogenically weathered volcanic rock. Changes in the hydrochemical properties reflect different stages of cryogenic weathering. The lithological characteristics mark the transition from an erosive site to a site with accumulation. This environmental change is linked to a relative lake level highstand at >13 000 yr BP, when a shoreline bar was formed leading to slope sedimentation. Lake level dropped by 4m during the Holocene. © 2007 The Authors, Journal compilation © 2007 The Boreas Collegium. 2008 English 03009483 10.1111/j.1502-3885.2007.00011.x Boreas 37 55-65 Alfred Wegener Institute for Polar and Marine Research, D-14473 Potsdam, Germany; Arctic and Antarctic Research Institute, Bering Street, 199397 St. Petersburg, Russian Federation 1 climate change; glacial deposit; highstand; lake level; paleoenvironment; paleohydrology; Quaternary; sedimentation rate; weathering, Chukchi; Elgygytgyn Lake; Eurasia; Russian Federation; Siberia https://www.scopus.com/inward/record.uri?eid=2-s2.0-62649085517&doi=10.1111%2fj.1502-3885.2007.00011.x&partnerID=40&md5=59865f6310e44291bd0aa86d6239fe5c cited By 30 G. Schwamborn G. Fedorov L. Schirrmeister H. Meyer H.-W. Hubberten article Nakano2008745 We measured 852 sets of planar deformation features (PDFs) in shocked quartz grains in impactite samples of the Yaxcopoil (YAX-1) core and from 4 Cretaceous/Tertiary (K/T) boundary deposits: the Monaca, the Cacarajícara, and the Peñalver formations in Cuba, and DSDP site 536, within 800 km of the Chicxulub crater, in order to investigate variations of PDF orientations in the proximity of the crater. Orientations of PDFs show a broad distribution with peaks at ω {1013}, π {1012}, and ξ {1112}, plus r, z {1011} orientations with minor c(0001), s{1121}, t{2241} plus x{5161}, and m{1010} plus a{1120} orientations. Planar deformation features with c(0001) orientation are relatively more abundant in the proximity of the Chicxulub crater than in distal sites such as North America, the Pacific Ocean, and Europe. This feature indicates that in the proximity of the crater, part of the shocked quartz grains in the K/T boundary deposits were derived from the low shock pressure zones. Moreover, the orientations of PDFs with ξ {1122} plus r, z {1011} are high in our studied sites, and frequencies of these orientations decrease with increasing distance from the crater. On the other hand, absence of c(0001) and the rare occurrence of PDFs with ξ {1122} plus r, z {1011} orientations in the sample from the YAX-1 core that was taken at the top of the impactite layer of the Chicxulub crater suggests that the sampling horizon that reflects a certain cratering stage is also an important factor for variations in shocked quartz. © The Meteoritical Society, 2008. 2008 10.1111/j.1945-5100.2008.tb00682.x Meteoritics and Planetary Science 43 745-760 Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo, Build 5, 7-3-1 Hongo, Tokyo 113-0033, Japan; Tsunami Engineering Laboratory, Disaster Control Research Center, Tohoku University, Aoba 06-6-11, Aramaki, Sendai 980-8579, Japan; Department of Complexity Science and Engineering, Graduate School of Frontier Science, The University of Tokyo, 7-3-1 Hongo, Tokyo 113-0033, Japan 4 https://www.scopus.com/inward/record.uri?eid=2-s2.0-52949154356&doi=10.1111%2fj.1945-5100.2008.tb00682.x&partnerID=40&md5=339fcbc0a0e760a74c3c0b7c4775a986 cited By 5 Y. Nakano K. Goto T. Matsui R. Tada E. Tajika article Parés2008 We present a protocol for using paleomagnetic analysis to determine the absolute orientation of core recovered from the SAFOD borehole. Our approach is based on determining the direction of the primary remanent magnetization of a spot core recovered from the Great Valley Sequence during SAFOD Phase 2 and comparing its direction to the expected reference field direction for the Late Cretaceous in North America. Both thermal and alternating field demagnetization provide equally resolved magnetization, possibly residing in magnetite, that allow reorientation. Because compositionally similar siltstones and fine-grained sandstones were encountered in the San Andreas Fault Zone during Stage 2 rotary drilling, we expect that paleomagnetic reorientation will yield reliable core orientations for continuous core acquired from directly within and adjacent to the San Andreas Fault during SAFOD Phase 3, which will be key to interpretation of spatial properties of these rocks. Copyright 2008 by the American Geophysical Union. 2008 English 00948276 10.1029/2007GL030921 Geophysical Research Letters 35 Department of Geological Sciences, University of Michigan, 2534 C. C. Little Building, Ann Arbor, MI 48109-1063, United States; Geology Department, University of Erlangen-Nuernberg, Schloßgarten 5, D-91054 Erlangen, Germany; U.S. Geological Survey, 345 Middlefield Road, Menlo Park, CA 94025, United States 2 Boreholes; Demagnetization; Magnetic fields; Magnetization; Sandstone; Tectonics, Fine-grained sandstones; Paleomagnetic analysis; Paleomagnetic reorientation, Geomagnetism, borehole; Cretaceous; demagnetization; paleomagnetism; remanent magnetization; San Andreas Fault, California; Central Valley [California]; North America; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-40849114815&doi=10.1029%2f2007GL030921&partnerID=40&md5=69f8f375b001572985f15c80978b6042 cited By 6 J.M. Parés A.M. Schleicher B.A. Pluijm S. Hickman article Bohnhoff200885 The most recent devastating earthquakes that occurred along the North Anatolian Fault Zone (NAFZ) in northwestern Turkey were the 1999 Izmit (Mw=7.4) and Düzce (Mw=7.1) events. In this study we present a catalog of Izmit aftershock hypocenters that was deduced from a network covering the entire 140 km long rupture of the mainshock. 7348 events with a location accuracy better than 5 km are analysed. Aftershocks were observed along the entire ruptured segment along a 20 km wide band of activity. Events are clustered in distinct regions and dominantly occur at 5 to 15 km depth. The eastern termination of the Izmit rupture is characterized by a sharp and steeply dipping boundary exactly where the Düzce mainshock initiated 87 days after the Izmit event. Relocation of the events using double-difference technology results in 4696 high-resolution hypocenters that allow resolving the internal structure of the seismically active areas with a resolution of 300 m (horizontal) and 400m (vertical). Below the Akyazi Plain, representing a small pull-apart structure at a triple junction of the NAFZ, we identify planes of activity that can be correlated with nodal planes of EW extensional normal faulting aftershocks. Along the easternmost Karadere-Düzce segment we identify the down-dip extension of the Karadere fault that hosted about 1 m of right-lateral coseismic slip. At the easternmost rupture we correlate a cloud-type distribution of seismic activity with the largest aftershocks in this area, a subevent of the Izmit mainshock and the Düzce mainshock that all have an almost identical focal mechanism. This part of the NAFZ is interpreted as a classical example of a seismic barrier along the fault. 2008 English 16807340 10.5194/adgeo-14-85-2008 Advances in Geosciences 14 European Geosciences Union 85-92 GeoForschungsZentrum Potsdam, Telegrafenberg D424, 14473 Potsdam, Germany aftershock; coseismic process; earthquake event; fault zone; faulting; Kocaeli earthquake 1999; seismotectonics; tectonic setting; triple junction, Anatolia; Duzce; Eurasia; Kocaeli [Turkey]; Turkey https://www.scopus.com/inward/record.uri?eid=2-s2.0-37749009216&doi=10.5194%2fadgeo-14-85-2008&partnerID=40&md5=654b5c1f13a5cf8932e4d7a0003ee782 cited By 4 M. Bohnhoff F. Bulut E. Görgün C. Milkereit G. Dresen article Korn2008479 A new network of permanently recording seismic stations in West Saxony has considerably improved detection threshold, location accuracy and depth determination in this seismically active region. Between 2001 and 2007 more than 900 events have been located. Seismicity mainly occurred along a band stretching north-south between Leipzig and Vogtland/NW Bohemia area with local magnitudes ranging between 0.8 and 2.8. Seismicity clearly delineates the Leipzig-Regensburg (L-R) fault zone striking N-S, and the Gera-Jachymov (G-J) fault zone striking roughly NNW-SSE. The hypocentral depths can be divided into two depth ranges, one at depths below 10 km, and a second at less than 10 km depth that only extends S-N from the Vogtland until the crossing between L-R and G-J fault zones. A small earthquake sequence that occurred near Werdau/ Zwickau in August 2006 at almost the same epicenters as an earlier sequence 1997/98 seems to confirm this finding: a relative localization of 15 events with the double-difference technique clearly reveals two distinct subclusters at about 6 and 12-14 km depth. With the improved station coverage 33 new fault plane solutions from events along the L-R fault zone north of the swarmquake area could be determined from P-polarities and P/S ratios. They do not differ significantly from solutions in the Vogtland/NW-Bohemia area and are mostly compatible with a N-S oriented fault plane. Strike slip mechanisms with or without a dip slip component dominate. © Institute of Geophysics of the ASCR, v.v.i 2008. Article 2008 English 00393169 10.1007/s11200-008-0033-z Studia Geophysica et Geodaetica 52 479 – 492 4 Central Europe; Eurasia; Europe; Germany; Saxony; earthquake epicenter; earthquake hypocenter; fault zone; seismicity; seismotectonics; source parameters; strike-slip fault https://www.scopus.com/inward/record.uri?eid=2-s2.0-57549090207&doi=10.1007%2fs11200-008-0033-z&partnerID=40&md5=864b7edeadad7a0f10f0f8f4cce6df3c Cited by: 13 M. Korn S. Funke S. Wendt article Anderson2008285 Gas hydrates, which are naturally occurring ice-like combinations of gas and water, have the potential to provide vast amounts of natural gas from the world's oceans and polar regions. However, producing gas economically from hydrates entails major technical challenges. Proposed recovery methods such as dissociating or melting gas hydrates by heating or depressurization are currently being tested. One such test was conducted in northern Canada by the partners in the Mallik 2002 Gas Hydrate Production Research Well Program. This paper describes how resistivity logs were used to determine the size of the annular region of gas hydrate dissociation that occurred around the wellbore during the thermal test in the Mallik 5L-38 well. An open-hole logging suite, run prior to the thermal test, included array induction, array laterolog, nuclear magnetic resonance and 1.1-GHz electromagnetic propagation logs. The reservoir saturation tool was run both before and after the thermal test to monitor formation changes. A cased-hole formation resistivity log was run after the test.Baseline resistivity values in each formation layer (Rt) were established from the deep laterolog data. The resistivity in the region of gas hydrate dissociation near the wellbore (Rxo) was determined from electromagnetic propagation and reservoir saturation tool measurements. The radius of hydrate dissociation as a function of depth was then determined by means of iterative forward modeling of cased-hole formation resistivity tool response. The solution was obtained by varying the modeled dissociation radius until the modeled log overlaid the field log. Pretest gas hydrate production computer simulations had predicted that dissociation would take place at a uniform radius over the 13-ft test interval. However, the post-test resistivity modeling showed that this was not the case. The resistivity-derived dissociation radius was greatest near the outlet of the pipe that circulated hot water in the wellbore, where the highest temperatures were recorded. The radius was smallest near the center of the test interval, where a conglomerate section with low values of porosity and permeability inhibited dissociation. The free gas volume calculated from the resistivity-derived dissociation radii yielded a value within 20 per cent of surface gauge measurements. These results show that the inversion of resistivity measurements holds promise for use in future gas hydrate monitoring. © 2008 Society of Petrophysicists and Well Log Analysts. All rights reserved. 2008 English 15299074 Petrophysics 49 285-294 Schlumberger, 89 Stony Hill Rd., Brookfield, CT 06804, United States; US Geological Survey, Denver Federal Center, Box 25046, Denver, CO 80225, United States; Schlumberger Oilfield Services, 5 Broadway Executive Park Building, 6601 Broadway Extension, Oklahoma City, OK 73116-8214, United States; Etudes et Productions Schlumberger, 1 rue Henri Becquerel, 92142 Clamart, Cedex, France 3 Cased-hole formation resistivity (CHFR); Depressurization; Electromagnetic propagation; Gas Hydrate production; Hydrate dissociation; logging suite; Magnetic (CE); Monitor (CO); Northern Canada; Openhole (OH); Polar Regions; Resistivity logs; Resistivity values; Technical challenges; Well bores, Density measurement (specific gravity); Dissociation; Electric logging; Electromagnetic logging; Gas industry; Gases; Hydrates; Hydration; Magnetic fields; Magnetic resonance; Magnetism; Monitoring; Nuclear magnetic logging; Nuclear magnetic resonance; Offshore oil well production; Oil well logging; Radioactivity logging; Resonance; Testing; Thermal logging; Well stimulation, Gas hydrates https://www.scopus.com/inward/record.uri?eid=2-s2.0-46449089372&partnerID=40&md5=4a66b4b0af85c5f7fac4d0e08b533a52 cited By 11 B.I. Anderson T.S. Collett R.E. Lewis I. Dubourg article Hesselbo200819 Sequence stratigraphy - the subdivision of successions into facies packages bounded by surfaces representing major shifts in depositional environment - has provided a systematic methodology for inference of relative sea-level change from vertical facies successions. In the present review, sequence stratigraphic work on exposures of British Jurassic successions is summarized. Resultant inferred relative sea-level curves for Early Jurassic and early Mid Jurassic successions show some strong similarities at the scale of ammonite zones between widely separated basins, implying sea-level change of at least regional extent or, alternatively, regionally co-ordinated changes in sediment supply. Also well developed are coeval stage-level influxes of sandy sediments into widely separated marine basins during the Late Pliensbachian, Late Toarcian-Aalenian and Oxfordian. Similarly, widespread synchronous shifts to more offshore facies are evident in the Early Pliensbachian, Early Toarcian, Early Callovian and Early Kimmeridgian. © 2008 Geologists' Association. Article 2008 English 00167878 10.1016/S0016-7878(59)80069-9 Proceedings of the Geologists' Association 119 Geological Society of London 19 – 34 1 Eurasia; Europe; United Kingdom; Western Europe; Ammonoidea; depositional sequence; facies; Jurassic; sea level change; sequence stratigraphy https://www.scopus.com/inward/record.uri?eid=2-s2.0-40049088138&doi=10.1016%2fS0016-7878%2859%2980069-9&partnerID=40&md5=7bc8fe1295f3c18881800cbea2489c1a Cited by: 82 Stephen P. Hesselbo article Wang200848 The CCSD-SK is the first scientific drilling well of whole core Cretaceous rocks in the continent of China, which is composed of two drilling wells: CCSD-SK I in the north and CCSD-SK II in the south. Totally, 62 layers of bedded and ellipsoidal dolostone were identified in the Nenjiang Formation during the description of CCSD-SK II. Dolostone nodular occurs as lens in the vertical section, and interior of the nodular is characterized by foliation which converges at both lateral edges. Under microscopic observation, dolostone is grey in the core and bright at the rim, and marl has been replaced, locally forming "leopard spot" dolomite. All these features indicate that dolomite of the Nengjiang Formation was the product of lacustrine facies limestone during penecontemporaneous replacement. The forming mechanism of dolostone of the Nenjiang Formation was that under the setting of the marine transgression of Late Cretaceous in the Songliao Basin, marls brought by turbidity flow and extinction of ostracoda began to deposit during the replacement, thus forming the dolostone. Article 2008 Chinese 10009515 Acta Geologica Sinica (English Edition) 82 Science Press 48 – 54 1 Asia; China; Eurasia; Far East; Songliao Basin; Ostracoda; Panthera pardus; Cretaceous; dolomite; dolostone; drilling; formation mechanism; hydrocarbon reserve; marl; transgression; turbidity https://www.scopus.com/inward/record.uri?eid=2-s2.0-44249093281&partnerID=40&md5=80f381ea20380d8f348da21b3f3a12a5 Cited by: 14 Guodong Wang Rihui Cheng Pujun Wang Youfeng Gao article Hanan200851 The Snake River Plain represents 17 m.y. of volcanic activity that took place as the North American continent migrated over a relatively fixed magma source, or hotspot. The identification of a clear seismic image of a plume beneath Yellowstone is compelling evidence that the Miocene to recent volcanism associated with the Columbia Plateau, Oregon High Lava Plains, Snake River Plain, Northern Nevada Rift and Yellowstone Plateau represents a single magmatic system related to a mantle plume. A remaining enigma is, why do radiogenic isotope signatures from basalts erupted over the Mesozoic-Paleozoic accreted terrains suggest a plume source while basalts erupted across the Proterozoic-Archean craton margin indicate an ancient subcontinental mantle lithosphere source? We show that ancient cratonic lithosphere like that of the Wyoming province superimposes its inherent isotopic composition on sublithospheric plume and/or asthenospheric melts. The results show that Yellowstone plume could have a radiogenic isotope composition similar to the mantle source of the early Columbia River Basalt Group and that the plume source composition has persisted to the present day. © 2008 The Geological Society of America. 2008 English 00917613 10.1130/G23935A.1 Geology 36 51-54 Department of Geological Sciences, San Diego State University, San Diego, CA 92182-1020, United States; Department of Geology, Utah State University, Logan, UT 84322-4505, United States; Department of Geology, Centenary College, Shreveport, LA 71134, United States 1 Lithosphere; Mantle plume; Volcanic activity, Basalt; Geochemistry; Isotopes; Tectonics; Volcanoes, Volcanic rocks, basalt; continental lithosphere; isotopic composition; lead isotope; mantle plume; mantle source; neodymium isotope; strontium isotope, Idaho; North America; Snake River Plain; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-38349057664&doi=10.1130%2fG23935A.1&partnerID=40&md5=c6e0b389b06c512525be01941edc64d2 cited By 71 B.B. Hanan J.W. Shervais S.K. Vetter article Paul2008394 This paper presents a wellbore-stability study of the San Andreas Fault Observatory at Depth (SAFOD) research borehole located near Parkfield, California, USA. In the summer of 2005, the SAFOD borehole was drilled successfully through the active trace of the San Andreas Fault (SAF) in an area characterized by fault creep and frequent microearthquakes. In this study, we report how the analysis of wellbore failures in the upper part of the hole, geophysical logs, and a model for stress gradients in the vicinity of the fault were used to estimate the mud weights required to drill through the fault successfully. Because logging-while-drilling (LWD) acoustic caliper data and real-time hole-volume calculations both showed that relatively little failure occurred while drilling through the SAF, the predicted mud weight was successful in drilling a stable borehole. However, a six-arm caliper log, run after drilling was completed, indicates that there was deterioration of the borehole with time, which appears to be caused by fluid penetration around the borehole. The LWD-resistivity measurements show that essentially no fluid penetration occurred as the hole was being drilled. Because of this, the mud weight used was capable of maintaining a stable wellbore. However, the resistivity data obtained after drilling show appreciable fluid penetration with time, thus negating the effectiveness of the mud weight and leading to time-dependent wellbore failure. Using finite-element modeling (FEM), we show that mud penetration into the fractured medium around the borehole causes failure with time. Copyright © 2008 Society of Petroleum Engineers. 2008 English 10646671 10.2118/102781-PA SPE Drilling and Completion 23 Society of Petroleum Engineers 394-408 Stanford University, Stanford, CA, United States; ConocoPhillips Subsurface Technology Group, Houston, TX, United States 4 Acoustic logging; Boring; Finite element method; Logging while drilling; Strike-slip faults, A-stable; California; Fault creep; Fluid penetration; Logging while drilling; Microearthquakes; Mud weights; San Andreas fault; Wellbore; Wellbore stability studies, Boreholes, borehole geophysics; borehole stability; creep; drilling; drilling fluid; finite element method; microearthquake; numerical model; San Andreas Fault, California; North America; Parkfield; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-58149348346&doi=10.2118%2f102781-PA&partnerID=40&md5=1bb07bdcccb48f9b7b0477270240d3b8 cited By 7 P.K. Paul M. Zoback article Gao2008669 CCSD-SK II is one of the two drilling wells of the Cretaceous Scientific Drilling Project in Songliao Basin. It is located at limb section of the nose-like structure in the Gulong sag of the central depression, north of Songliao Basin. Based on the detailed description on the cores from the second member bottom of Nenjiang Formation to the third member top of Quantou Formation in CCSD-SK II, the core profile was established, and five common lithology (mudstone, silty mudstone, mudy siltstone, siltstone and sandstone) and eight special lithology (dolomite, volcanic ash, oil shale, lime mudstone, marlite, recrystalline limestone, ostracode clastic limestone and ostracode limestone) were identified. 172 layers of special lithology in CCSD-SK II were recognized with a total thickness of 14. 516m. They are distributed mainly in the Qingshankou Formation, the second and third member of Yaojia Formation and Nenjiang Formation. The detailed description of the cores and identification on special lithology are the base for the next studies. Article 2008 Chinese 10009515 Acta Geologica Sinica (English Edition) 82 Science Press 669 – 675 5 Asia; China; Eurasia; Far East; Songliao Basin; Ostracoda; Chinese Continental Scientific Drilling Project; core logging; Cretaceous; drilling fluid; lithology; site selection https://www.scopus.com/inward/record.uri?eid=2-s2.0-49149112700&partnerID=40&md5=b5b1b1b1be2d6e6099cc67158c110406 Cited by: 13 Youfeng Gao Pujun Wang Chengshan Wang Yanguang Ren Guodong Wang Wanzhu Liu Rihui Cheng article oberhansli2008water2 2008 GFZ Data Services Hedi Oberhänsli article oberhansli2008water1 2008 GFZ Data Services Hedi Oberhänsli article Vetere2008208 The viscosity of an iron-bearing melt with composition similar to Unzen andesite was determined experimentally in the high (109-1010.5 Pa s) and low (5-1000 Pa s) viscosity range using a parallel plate viscometer and the falling sphere method, respectively. Falling sphere experiments were carried out in an internally heated argon pressure vessel and in a piston cylinder apparatus at 1323 to 1573 K and 200 to 2000 MPa. Creep experiments were performed in the temperature range of 747-845 K at 300 MPa. The water content of the melt varies from nominally dry to 6.2 wt.% H2O. The Fe2+/Fetot ratio was determined for each sample in the quenched glass using a colorimetric method. Pressure has minor influence on the viscosity compared with the effect of temperature, water content (main compositional parameter controlling the viscosity) or with the Fe2+/Fetot ratio (especially important at low water content of the melt). Based on our new viscosity data and literature data with measured Fe2+/Fetot ratio we propose a new empirical equation to estimate the viscosity η (in Pa s) of andesitic melts as a function of temperature T (in K), water content w (in wt.%) and Fe2+/Fetot ratio. The derived relationship reproduces the experimental data (87 in total) in the viscosity range from 100.5 to 1013 Pa s with a 1σ standard deviation of 0.17 log units. However, application of this calculation model is limited to Fe2+/Fetot Fetot &gt; 0.3 and to temperatures above Tg. Moreover, in the high viscosity range the variation of viscosity with water content is constrained only by few experimental data and needs verification by additional measurements. The viscosity data are used to interpret mixing processes in the Unzen magma chamber prior to 1991-1995 eruption. We demonstrate that the viscosities of the rhyolite and andesite melts from the two end-member magmas are nearly identical prior and during mixing, enabling efficient magma mixing. © 2008 Elsevier B.V. All rights reserved. 2008 English 03770273 10.1016/j.jvolgeores.2008.03.028 Journal of Volcanology and Geothermal Research 175 208-217 Institut für Mineralogie, Universität Hannover, Callinstr. 3, D-30167 Hannover, Germany; Istituto Nazionale di Geofisica e Vulcanologia (INGV), via di Vigna Murata 605, I-00143 Roma, Italy; Poliklinik für Zahnärztliche Prothetik, Medizinische Hochschule, Carl-Neuberg-Str. 1, D-30625 Hannover, Germany 1-2 Igneous rocks; Iron; Mixing; Viscometers; Viscosity, andesite melt; dissolved water; magma mixing; redox state of iron; Unzen, Hydrodynamics, andesite; magma chamber; redox conditions; rhyolite; viscosity; volcanic eruption; water content, Asia; Eurasia; Far East; Japan; Kyushu; Nagasaki [Kyushu]; Unzen Volcano https://www.scopus.com/inward/record.uri?eid=2-s2.0-50049129893&doi=10.1016%2fj.jvolgeores.2008.03.028&partnerID=40&md5=1320cb47ad39728dcba2974e0b6c8387 cited By 37 F. Vetere H. Behrens J.A. Schuessler F. Holtz V. Misiti L. Borchers article Bennington20082934 We present models of the three-dimensional (3D) seismic attenuation structure, both Q p and Q s for a 16 km 2 area centered on the San Andreas Fault Observatory at Depth (SAFOD). The P- and S-wave t*-values used in the inversion were determined from local earthquake data recorded by seismic network and portable array stations within the Parkfield region by inverting arrival spectra for source parameters, t* and site response. Two techniques for determining the site response, the joint and alternating methods, were compared and it was found that the alternating method significantly underestimated site response variations. The t*-values were inverted to obtain 3D frequency-independent Q p and Q s models using 3D V p and V s models and associated event locations. A shallow low-Q area (Q p and Q s about 50-75) on the southwest edge of both models is attributed to the low-velocity Cenozoic sedimentary rocks that overlie the Salinian basement rock. A high-Q feature (Q p and Q s about 250 to 300) abuts this area and is interpreted as the Salinian basement. Adjacent to the San Andreas fault (SAF) trace, on its southwest side, there is a low-Q feature (Q p and Q s about 50-80) attributed to a wedge of sedimentary rocks; uniformly low Q p- and Q s-values suggest that the wedge is fluid rich. A low-Q basin feature (Q p and Q's about 50-75) on the northeast side of the SAF is interpreted as a fluid rich zone. Beneath this area there is a high-Q feature (Q p and Q s about 220-300), which may be caused by crack closure due to increased pressure with depth in the rocks of the Franciscan formation. Given these high Q-values, it seems unlikely that this area acts as a fluid pathway for fluids entering the fault zone from the east into the seismogenic zone of the SAF. 2008 English 00371106 10.1785/0120080175 Bulletin of the Seismological Society of America 98 2934-2947 Department of Geology and Geophysics, University of Wisconsin-Madison, Madison, WI, United States; Department of Earth and Environmental Sciences, Rensselaer Polytechnic Institute, United States 6 Alternating methods; California; Cenozoic; Earthquake datum; Event locations; Fault zones; Fluid pathways; Low velocities; Portable arrays; Q-values; Salinian basements; San andreas faults; Seismic attenuations; Seismic networks; Seismogenic zones; Site response; Source parameters; Three-dimensional (3D), Buildings; Crack closure; Earthquakes; Fluids; Sedimentology; Tectonics; Three dimensional, Sedimentary rocks, data inversion; fault zone; P-wave; S-wave; San Andreas Fault; seismic attenuation; seismic data; seismic source; three-dimensional modeling, California; North America; Parkfield; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-63049099031&doi=10.1785%2f0120080175&partnerID=40&md5=78f1a2ceaab0bed46b3c8b3cdee718e4 cited By 31 N. Bennington C. Thurber S. Roecker article Wagner2008341 Lake Ohrid, at the Macedonian/Albanian border, was likely tectonically formed during the Tertiary and therefore is one of the oldest lakes in Europe. However, only a few studies exist concerning the potential of Lake Ohrid sediments for long-term palaeoenvironmental reconstructions within the scope of future potential deep-drilling campaigns. Therefore, as a first step, a transect of short surface sediment cores was investigated for chronology, physical properties, grain size, and biogeochemistry. The results were compared with information derived from a shallow hydro-acoustic seismic survey. The investigations indicate a rather uniform and bioturbated sedimentation in the central part of the lake basin with mean sedimentation rates of ca. 0.5-1 mm/year. The sediment composition is dominated by authigenetic carbonates. Diatom frustules or fragments form the major part of biogenic matter deposits, as indicated by the relatively high contents of biogenic opal and low contents of total organic carbon and total nitrogen. The shallow hydro-acoustic seismic survey indicates that horizons of sediment redeposition occur sporadically. Towards the shore of the lake, the sedimentation rate increases and sedimentation is increasingly influenced by local inflows or mass-movement processes triggered by tectonic activities. Thus Lake Ohrid has a high potential for palaeoenvironmental reconstructions on a multi-decadal scale and provides additional information concerning tectonic activity in the region. © 2007 Elsevier B.V. All rights reserved. Article 2008 English 00310182 10.1016/j.palaeo.2007.10.015 Palaeogeography, Palaeoclimatology, Palaeoecology 259 Elsevier B.V. 341 – 356 2-3 Albania; Eurasia; Europe; Lake Ohrid; Macedonia [Southern Europe]; Southern Europe; Bacillariophyta; biogeochemistry; bioturbation; chronology; comparative study; core analysis; grain size; lacustrine deposit; mass movement; paleoenvironment; physical property; reconstruction; sedimentation rate; seismic survey; tectonics; Tertiary https://www.scopus.com/inward/record.uri?eid=2-s2.0-40149110826&doi=10.1016%2fj.palaeo.2007.10.015&partnerID=40&md5=81111f5a66c4846467dbda59d85f83cc Cited by: 63 Bernd Wagner Klaus Reicherter Gerhard Daut Martin Wessels Andreas Matzinger Antje Schwalb Zoran Spirkovski Mitat Sanxhaku article Schultheiß2008141 The morphologically remarkable endemic fauna within ancient lakes has received much attention in the literature. More inconspicuous taxa, however, often lack detailed molecular and morphometrical examination, although their proportion of the endemic fauna of an ancient lake must not be underestimated. Consequently, a better understanding of evolutionary patterns and processes within these lakes requires more knowledge about the often-neglected inconspicuous taxa. In the present study, we focus on the notoriously cryptic pea clam genus Pisidium (Bivalvia: Sphaeriidae). Though the genus is widely distributed, most endemic species are reported only from ancient lakes, including the European ancient sister lake system of Ohrid and Prespa on the Balkan Peninsula. Here we test for the first time hypotheses on the evolution of the endemic pea clams in this European biodiversity hotspot by molecular means. Combining a broad 16S phylogeny (comprising most European pea clam species), network analyses and morphometrical analyses, we found interesting biogeographical patterns and provide evidence for cryptic species in both lakes. Furthermore, we confirmed the proposed sister-species relationship of the endemics P. edlaueri in Lake Ohrid and P. maasseni in Lake Prespa, and we suggest scenarios of the endemic pea clam evolution within both lakes. The patterns of speciation found in the genus Pisidium are compared to patterns in morphologically distinct molluscan groups in lakes Ohrid und Prespa. © 2008 Springer Science+Business Media B.V. Conference paper 2008 English 15735117 10.1007/s10750-008-9553-3 Hydrobiologia 615 141 – 156 1 Eurasia; Europe; Lake Mikri Prespa; Lake Ohrid; Southern Europe; Bivalvia; Mollusca; Pisidium; Pisum sativum; Sphaeriidae (bivalves); Biodiversity; Electric network analysis; Graph theory; Network protocols; Sensor networks; endemic species; fauna; lake; mollusc; morphometry; phylogenetics; phylogeography; speciation (biology); taxonomy; Ancient lakes; Cryptic speciation; Morphometrics; Phylogenetics; Pisidium; Pisidium edlaueri; Pisidium maasseni; Lakes https://www.scopus.com/inward/record.uri?eid=2-s2.0-53649091991&doi=10.1007%2fs10750-008-9553-3&partnerID=40&md5=75500f2aa3af21e3b821c0853b629060 Cited by: 43 Roland Schultheiß Christian Albrecht Ulrich Bößneck Thomas Wilke article Wagner200871 A 1075 cm long core (Lz1120) was recovered in the south-eastern part of the Lake Ohrid (Republics of Macedonia and Albania) and sampled for identification of tephra layers. Magnetic susceptibility investigations show rather high magnetic values throughout the core, with peaks unrelated to the occurrence of tephra layers but instead to the relative abundance of detrital magnetic minerals in the sediment. Naked-eye inspection of the core allowed us to identify of two tephra layers, at 896-897 cm and 1070-1075 cm. Laboratory inspection of the grain-size fraction > 125 μm allowed for the identification of a third cryptotephra at 310-315 cm. Major element analyses on glass shards of the tephra layers at 896-897 cm and 1070-1075 cm show a trachytic composition, and indicate a correlation with the regionally dispersed Y-3 and Y-5 tephra layers, dated at ca 30 and 39 cal ka BP. The cryptotephra at 310-315 cm has a mugearitic-benmoreitic composition, and was correlated with the FL eruption of Mt. Etna, dated at 3370 ± 70 cal yr BP. These ages are in agreement with five 14C AMS measurements carried out on plant remains and macrofossils from the lake sediments at different depths along the core. The recognition of distal tephra from Italian volcanoes allows us to link the Lake Ohrid succession to other archives located in the Mediterranean area and in eastern Europe. The benmoreitic-mugearitic tephra layer at 310-315 cm is the first recognition in the Balkan area of a distal ash deposit from a mid-intensity explosive eruption of Mt. Etna, as far as 600 km from the source. © 2007 Elsevier B.V. All rights reserved. Article 2008 English 03770273 10.1016/j.jvolgeores.2007.08.018 Journal of Volcanology and Geothermal Research 177 71 – 80 1 Albania; Eurasia; Europe; Macedonia [Southern Europe]; Mediterranean Sea; Southern Europe; Backpropagation; Landforms; Magnetic materials; Magnetic properties; Magnetic susceptibility; Minerals; Sedimentation; Sedimentology; Volcanoes; biostratigraphy; dispersion; explosive volcanism; magnetic susceptibility; tephra; tephrochronology; trachyte; volcanic ash; volcanic eruption; volcanology; Albania/Macedonia; Italian volcanoes; Lake Ohrid; tephrochronology; tephrostratigraphy; Lakes https://www.scopus.com/inward/record.uri?eid=2-s2.0-53949105072&doi=10.1016%2fj.jvolgeores.2007.08.018&partnerID=40&md5=22f84b2c90a45246fa28b8e53be0f983 Cited by: 61 B. Wagner R. Sulpizio G. Zanchetta S. Wulf M. Wessels G. Daut N. Nowaczyk article Shanahan2008339 The sediments from Lake Bosumtwi, Ghana contain a unique record of fine-scale (mm to sub-mm) laminations, which will provide a valuable annual chronometer for reconstructing paleoenvironmental changes in West Africa covering much of the last 1 Ma. Comparisons of laminae counts to independent 210Pb dates and the rise in anthropogenic "bomb" radiocarbon support the interpretation of the laminations in the uppermost sediments as registering annual events. Radiocarbon dates on in-situ fish-bone collagen are in agreement with varve counts, further supporting the annual nature of our varve chronology. Over the instrumental period (1925-1999), dark-varve thickness measurements are correlated with local rainfall (r = 0.54) and appear able to resolve decadal-scale changes in precipitation. The relationship between varve thickness and rainfall provides support for our interpretation that dark-colored varve thickness records catchment runoff during the rainy season rather than dust flux during the dry season. Dark laminae alternate with organic and carbonate-rich light laminae formed during the fall period of enhanced productivity. Downcore, varves undergo significant microstratigraphic and geochemical variations, but retain the same pattern of alternating clastic and organic-rich laminae, providing support that the laminae may represent annual time markers for reconstructions of the deeper part of the record. © 2007 Springer Science+Business Media B.V. Article 2008 English 09212728 10.1007/s10933-007-9164-4 Journal of Paleolimnology 40 339 – 355 1 Africa; Ashanti; Ghana; Lake Bosumtwi; Sub-Saharan Africa; West Africa; biogeochemistry; collagen; comparative study; crater lake; environmental indicator; lacustrine deposit; lamination; lead isotope; paleoenvironment; precipitation assessment; radiocarbon dating; reconstruction; stratigraphy; varve https://www.scopus.com/inward/record.uri?eid=2-s2.0-46249119211&doi=10.1007%2fs10933-007-9164-4&partnerID=40&md5=670f7c275cd5aeb934abd023913e385e Cited by: 36 Timothy M. Shanahan Jonathan T. Overpeck J. Warren Beck C. Winston Wheeler John A. Peck John W. King Christopher A. Scholz article pasek2008session 2008 Astrobiology 8 Mary Ann Liebert, Inc. 140 Huguenot Street, 3rd Floor New Rochelle, NY 10801~… 356--361 2 Matthew Pasek Dominic Papineau Jelte Harnmeijer article Hauswald2008169 Ancient lakes have long been recognized as "hot spots of evolution" and "evolutionary theatres" and they have significantly contributed to a better understanding of speciation and radiation processes in space and time. Yet, phylogenetic relationships of many ancient lake taxa, particularly invertebrate groups, are still unresolved. Also, the lack of robust morphological, anatomical, and phylogeographical data has largely prevented a rigorous testing of evolutionary hypotheses. For the freshwater gastropod genus Valvata-a group with a high degree of endemism in several ancient lakes-different evolutionary scenarios are suggested for different ancient lakes. Lake Baikal, for example, is inhabited by several endemic Valvata taxa that presumably do not form a monophyletic group. For such an evolutionary pattern, the term ancient lake species scatter is introduced here. In contrast, for the Balkan Lake Ohrid, workers previously suggested the presence of a monophyletic group of endemic Valvata species, that is, an ancient lake species flock. Sequence data of the mitochondrial cytochrome oxidase c subunit I gene (COI) from worldwide taxa, with a strong emphasis on Balkan species, are here used to test whether the putative Ohrid Valvata endemics represent an ancient lake species flock and to study patterns of speciation both on the Ohrid and the Balkan scale. The study reveals three distinct clades of endemic Valvata in Lake Ohrid. Monophyly of these taxa, however, is rejected, and they therefore do not represent an ancient lake species flock, but rather an ancient lake species scatter. Also, in contrast to many other gastropod groups in Lake Ohrid, the valvatids apparently did not radiate. Many Valvata taxa in ancient lakes are characterized by enhanced levels of shell complexity. However, it remains unclear whether these patterns are associated with ancient lake environments per se. It is here suggested that similarities in shell structure between North American and Balkan taxa might simply be due to convergent evolution. © 2008 Springer Science+Business Media B.V. Conference paper 2008 English 15735117 10.1007/s10750-008-9556-0 Hydrobiologia 615 169 – 179 1 Eurasia; Europe; Lake Mikri Prespa; Lake Ohrid; Southern Europe; Gastropoda; Invertebrata; Valvata; Valvatida; Digital signal processing; Shells (structures); evolutionary biology; freshwater ecosystem; gastropod; lake; phylogenetics; species flock; taxonomy; Ancient lake species flock; Ancient lake species scatter; Ancient lakes; Lake Ohrid; Lake Prespa; Valvata; Lakes https://www.scopus.com/inward/record.uri?eid=2-s2.0-53649092343&doi=10.1007%2fs10750-008-9556-0&partnerID=40&md5=ddc101ddd6b1fce23b5fe1408bb5d135 Cited by: 29 Anne-Kathrin Hauswald Christian Albrecht Thomas Wilke article Xu2008138 Temperature variations at Lake Qinghai, northeastern Qinghai-Tibet plateau, were reconstructed based on four high-resolution temperature indicators of the δ18O and the δ13C of the bulk carbonate, total carbonate content, and the detrended δ15N of the organic matter. There are four obvious cold intervals during the past 600 years at Lake Qinghai, namely 1430-1470, 1650-1715, 1770-1820, and 1920-1940, synchronous with those recorded in tree rings at the northeast Qinghai-Tibet plateau. The intervals of 1430-1470, 1650-1715, and 1770-1820 are consistent with the three coldest intervals of the Little Ice Age. These obvious cold intervals are also synchronous with the minimums of the sunspot numbers during the past 600 years, suggesting that solar activities may dominate temperature variations on decadal scales at the northeastern Qinghai-Tibet plateau. © 2007 Elsevier Ltd. All rights reserved. Article 2008 English 13646826 10.1016/j.jastp.2007.09.006 Journal of Atmospheric and Solar-Terrestrial Physics 70 138 – 144 1 Atmospheric composition; Carbonates; Meteorology; Solar energy; Decadal scales; Solar activity; Sunspot; Temperature variation; Atmospheric temperature https://www.scopus.com/inward/record.uri?eid=2-s2.0-37349112200&doi=10.1016%2fj.jastp.2007.09.006&partnerID=40&md5=0402a93f2846f150d54ed72f20adcd14 Cited by: 18 Hai Xu Xiaoyan Liu Zhaohua Hou article Suto200820 The Unzen Scientific Drilling Project was initiated in 1999 to investigate a magma conduit that had recently fed a volcanic eruption. The conduit hole, USDP-4, was drilled to 810 m in 2003. In 2004, the hole was extended with intention of reaching the conduit at a drilled depth of about 2000 m. This objective was achieved, and the final measured depth of USDP-4 was 1995.75 m. A new temperature memory gauge for rotary drilling application was designed and developed for the project in order to measure borehole temperatures as often as possible in the expected high temperature environment near the conduit. Temperature ratings of the tool are up to 250 °C with dewar. A total of 10 surveys were conducted at depths of 1555-1995.75 m. This tool was used in six surveys, and borehole temperature data was successfully obtained from all surveys. Based on the measured temperatures, it is apparent that the thermal energy potential of the conduit regime (i.e. thermal supply from conduit) is not large compared to that of most known geothermal systems. Formation temperatures along the conduit hole were estimated from measured temperatures by using a borehole temperature simulator, which we developed and subsequently modified. According to the simulation, the maximum in the formation temperature profile is located at a depth of about 1970 m, and its temperature was about 170 °C before the drilling operation started. This maximum approximately coincides with the center of the conduit, but is surprisingly low for a system that ceased eruption only 9 years before the temperature survey. © 2008 Elsevier B.V. 2008 English 03770273 10.1016/j.jvolgeores.2008.03.034 Journal of Volcanology and Geothermal Research 175 20-27 Graduate School of Environmental Studies, Tohoku University, Japan; Geothermal Engineering Co., Ltd., Japan; Ichinoseki National College of Technology, Japan; Sandia National Laboratory, United States 1-2 Drilling; Estimation; Gages; Geothermal energy; Geothermal fields; Surveys; Volcanoes, Bore hole; borehole temperature; Drilling operations; Energy potential; formation temperature; Geothermal systems; High-temperature environments; Measured depth; Rotary drilling; temperature memory gauge; temperature simulation; temperature survey; volcanic conduit; Volcanic eruptions, Boreholes, borehole logging; drilling; gauge; geothermal system; magma; temperature profile; volcanic eruption, Asia; Eurasia; Far East; Japan; Kyushu; Nagasaki [Kyushu]; Unzen Volcano https://www.scopus.com/inward/record.uri?eid=2-s2.0-50049118836&doi=10.1016%2fj.jvolgeores.2008.03.034&partnerID=40&md5=9aa671f719a411e6d732acdb380e9446 cited By 8 Y. Suto S. Sakuma H. Takahashi N. Hatakeyama J. Henfling article Burt2008755 Before base surges were described in association with nuclear blasts and explosive volcanic eruptions (especially, the 1980 eruption of Mount St. Helens, Washington), laminar and cross-bedded volcanogenic surge deposits were commonly misinterpreted as being of fluvial or aeolian origin. One well-documented example involves the "water-laid tuffs" in and near the Spor Mountain beryllium mine, Utah; other examples abound. In light of how frequently volcanogenic surge deposits have been misinterpreted on Earth, extreme caution is urged for Mars studies. Contrary to what has been claimed, the markedly cross-bedded, salty deposits at Meridiani Planum on Mars need not have been formed by a combination of aeolian and aqueous processes, and their contained hematitic spherules need not have formed as aqueous concretions. Given the lack of indications of volcanism in the vicinity, and the planet-wide abundance of impact craters, deposition by surges associated with distant impact targets consisting of brine-soaked, locally sulfidic regolith is a reasonable explanation for all features observed, especially if diagenesis and weathering are considered. The uniformly sized and shaped, Ni-enriched blue-gray hematitic spherules would then be some type of vapor condensation spherules (including accretionary lapilli). A similar interpretation is possible for deposits in the Home Plate area, Gusev Crater. Unlike on the dry and atmosphereless Moon, salty impact surge deposits containing spherules should be common, and well-preserved, on Mars. © 2008 Elsevier B.V. 2008 10.1016/j.jvolgeores.2008.01.044 Journal of Volcanology and Geothermal Research 177 755-759 School of Earth and Space Exploration, Arizona State University, Box 871404, Tempe, AZ 85287-1404, United States; Los Alamos National Laboratory, Los Alamos, NM 87545, United States; Deparment of Geology, SUNY at Buffalo, 876 Natural Science Complex, Buffalo, NY 14260, United States 4 https://www.scopus.com/inward/record.uri?eid=2-s2.0-55649095529&doi=10.1016%2fj.jvolgeores.2008.01.044&partnerID=40&md5=cf3e24f04b371cfb2ae13e843ab0dd2c cited By 3 D.M. Burt L.P. Knauth K.H. Wohletz M.F. Sheridan article Deng2025 Article 2008 10.3969/j.issn.1672-7428.2008.03.001 Exploration Engineering 3 1-4 Y. Zhu W. Wang article Sun20084 Article 2008 Drilling Fluid and Completion Fluid 25 4–6+83 3 https://www.scopus.com/inward/record.uri?eid=2-s2.0-62149130061&partnerID=40&md5=88bd9d92e9b3984edd944d1b7166820c Cited by: 0 Ping-he Sun Xiao-ming Wu Yong-yi Zhu Ji-hua Cai article Botcharnikov2008168 The compositions of homogenized melt inclusions trapped in plagioclase (Pl) microphenocrysts (40-200 μm length) from mafic enclaves within dacitic rocks erupted at Unzen volcano in 1991-95 were investigated. The SiO2 contents of the melt inclusions vary from 58 to 70 wt.% and Pl anorthite content is An50-70. The stability fields (in terms of temperature and water activity) of natural Pl and coexisting melts from the melt inclusions were estimated from data of phase equilibria experiments performed with a synthetic andesite composition at T = 900-1140 °C, P = 200 MPa, log fO2 = NNO-2-NNO, and water activity of about 0-1. This composition is representative of the average composition of mafic enclaves from the 1991-95 eruption and nearly identical to the composition of andesitic lavas from 1663 Unzen eruption. The temperatures and H2O melt concentrations, calculated using the compositions of coexisting Pl and melt inclusions, provide an estimation of the conditions of andesitic magma evolution within the mafic enclaves prior to eruption. The formation of melt inclusions in plagioclase microphenocrysts occurred at a maximum temperature of ~ 1010 ± 35 °C for a melt containing 2 wt.% H2O and a minimum temperature of ∼ 945 °C ± 30 °C for a melt with ∼ 4 wt.% dissolved H2O. The compositional range of the melt inclusions indicates that the composition of the mafic enclave was not significantly contaminated by the host magma when inclusions were formed. The difference between concentrations of dissolved S (up to 0.06 wt.%) and Cl (up to 0.05 wt.%) in melt inclusions in Pl of mafic enclaves and concentrations of S (&lt; 0.005 wt.%) and Cl (0.05-0.11 wt.%) in melt inclusions in phenocrysts of the dacitic magma clearly implies that two distinct sources for S and Cl in the 1991-95 eruption of Unzen volcano need to be considered. Sulfur degassing was generated by a release of fluids from the high-temperature andesitic magma whereas Cl was degassed from the low-temperature silicic magma. The combination of data from melt inclusions and phase equilibria experiments indicates that the mafic end-member magma at Unzen was already partially crystallized and contained significant proportions (20 to 40 wt.%) of Pl and orthopyroxene (Opx) when melt inclusions started to form. Since clinopyroxene (Cpx) and magnetite (Mt) crystallize after Pl and Opx, the temperatures derived for the mafic end-member magma from coexisting Opx-Cpx and Ilm-Mt pairs do not represent temperatures near to the liquidus. Assuming that the injected mafic magma was nearly aphyric, its initial temperature might have been higher than estimated in previous studies. © 2008 Elsevier B.V. All rights reserved. 2008 English 03770273 10.1016/j.jvolgeores.2008.03.026 Journal of Volcanology and Geothermal Research 175 168-180 Institut für Mineralogie, Leibniz Universität Hannover, Callinstr. 3, 30167 Hannover, Germany; Department of Earth and Planetary Science, Kobe University, Kobe, 657-8501, Japan 1-2 Chemical engineering; Feldspar; Landforms; Silicate minerals; Silicon compounds; Volcanic rocks; Volcanoes, andesite; experiment; magma mixing; melt inclusions; storage conditions; Unzen volcano; volatiles, Phase equilibria, andesite; clinopyroxene; magma; magnetite; melt inclusion; phase equilibrium; volatile element; volcanic eruption, Asia; Eurasia; Far East; Japan; Kyushu; Nagasaki [Kyushu]; Unzen Volcano https://www.scopus.com/inward/record.uri?eid=2-s2.0-42549100320&doi=10.1016%2fj.jvolgeores.2008.03.026&partnerID=40&md5=bf71003951e7904107b86f41469ef4a9 cited By 25 R.E. Botcharnikov F. Holtz R.R. Almeev H. Sato H. Behrens article Thompson2008163 Hawaiian Island flank failures are recognized as the largest landslide events on Earth, reaching volumes of several thousand cubic kilometers and lengths of over 200 km and occurring on an average of once every 100 000 years. The 3.1 km deep Hawaii Scientific Drilling Project (HSDP) enabled an investigation of the rock mass strength variations on the island of Hawaii [Schiffman, P., Watters, R.J., Thompson, N., Walton, A.W., 2006. Hyaloclastites and the slope stability of Hawaiian volcanoes: insights from the Hawaiian Scientific Drilling Project's 3-km drill core. Journal of Volcanology and Geothermal Research, 151 (1-3): 217-228]. This study builds on that of Schiffman et al. [Schiffman, P., Watters, R.J., Thompson, N., Walton, A.W., 2006. Hyaloclastites and the slope stability of Hawaiian volcanoes: Insights from the Hawaiian Scientific Drilling Project's 3-km drill core. Journal of Volcanology and Geothermal Research, 151 (1-3): 217-228] by considering more in-depth rock mass classification and strength testing methods of the HSDP core. Geotechnical core logging techniques combined with laboratory strength testing methods show that rock strength differences exist within the edifice. Comparing the rock strength parameters obtained from the various volcano lithologies identified weak zones, suggesting the possible location of future slip surfaces for large flank failures. Relatively weak rock layers were recognized within poorly consolidated hyaloclastite zones, with increases in strength based on degree of alteration. Subaerial and submarine basalt flows are found to be significantly stronger. With the aid of digital elevation models, cross-sections have been developed of key flank areas on the island of Hawaii. Limit equilibrium slope stability analyses are performed on each cross-section using various failure criteria for the rock mass strength calculations. Based on the stability analyses the majority of the slopes analyzed are considered stable. In cases where instability (i.e. failure) is predicted, decreased rock mass quality (strength) of the altered and highly poorly consolidated lithologies is found to have a significant influence. These lithologies are present throughout the Hawaiian Islands, representing potential failure surfaces for large flank collapses. Failure criterion input parameters are considered in sensitivity analyses as are the influences of certain external stability factors such as sea level variation and seismic loading. © 2007 Elsevier B.V. All rights reserved. Article 2008 English 03770273 10.1016/j.jvolgeores.2007.11.008 Journal of Volcanology and Geothermal Research 171 163-177 School of Conservation Sciences, Bournemouth University, United Kingdom; Department of Geological Sciences and Engineering, University of Nevada, Reno, United States; Department of Geology, University of California, Davis, United States 3-4 Failure analysis; Landslides; Lithology; Sensitivity analysis; Volcanic rocks, Digital elevation models; Edifice stability; Hawaiian Island flank failures; Volcanic slope stability, Volcanoes, collapse; core logging; digital elevation model; failure analysis; limit analysis; rock mass classification; sensitivity analysis; slope stability; stability analysis; strength; testing method, Hawaiian Islands; Pacific islands; Pacific Ocean https://www.scopus.com/inward/record.uri?eid=2-s2.0-41749100594&doi=10.1016%2fj.jvolgeores.2007.11.008&partnerID=40&md5=b02ea5897d32e08cda434597cd11c8cd cited By 12 N. Thompson R.J. Watters P. Schiffman article Phedorin2008445 The analysis of sediment chemistry and biota in drill cores from Lake Khubsugul in Mongolia (KDP-01) and Lake Baikal in Siberia (BDP-96/1), two great Eurasian freshwater lakes, detected prominent climate and biological events at 460-420 and 670 kyrs BP in addition to the orbital cycles of precession, tilt and eccentricity. The revealed long-term events were associated with notable changes in biodiversity and geography/landscapes, mainly in water budgets and weathering patterns. The span between 460-420 and 670 kyrs BP was the time when the climate and geographic conditions differed from those before and after these events. The corresponding 33-24 m (670-460 kyr) interval of the Khubsugul core lacked the usual signature of the Milankovitch glacial/interglacial cycles. Events of approximately these ages were found in some other continental ecosystems and in oceanic δ13C records. The two events may mark the phases of a 300-500-kyr long supercycle (or megastadial) in the evolution of continental ecosystems. Among other causes (e.g., regional tectonic events), this periodicity, being globally correlated, may be associated with the 400-kyr cycle of the Earth's orbital eccentricity. © 2007 Springer Science+Business Media B.V. Article 2008 English 09212728 10.1007/s10933-007-9172-4 Journal of Paleolimnology 40 445 – 452 1 Asia; Eurasia; Far East; Hvsgol Aymag; Lake Baikal; Lake Khubsugul; Mongolia; Russian Federation; biodiversity; biota; carbon isotope; eccentricity; glacial-interglacial cycle; paleolimnology; periodicity; Pleistocene; sediment chemistry; water budget https://www.scopus.com/inward/record.uri?eid=2-s2.0-46249084128&doi=10.1007%2fs10933-007-9172-4&partnerID=40&md5=251cb3f8c92eb12e67314582dbb95acd Cited by: 17 Mikhail Albertovich Phedorin Andrey P. Fedotov Svetlana S. Vorobieva Galina A. Ziborova article LIU20082973 In this study, we link mineral inclusion data, trace element analyses, U–Pb age and Hf isotope composition obtained from distinct zircon domains of complex zircon to unravel the origin and multi-stage metamorphic evolution of amphibolites from the Sulu ultrahigh-pressure (UHP) terrane, eastern China. Zircon grains separated from amphibolites from the CCSD-MH drill hole (G12) and Niushan outcrop (G13) were subdivided into two main types based on cathodoluminescence (CL) and Laser Raman spectroscopy: big dusty zircons with inherited cores and UHP metamorphic rims and small clear zircons. Weakly zoned, grey-white luminescent inherited cores preserve mineral inclusions of Cpx+Pl+Ap±Qtz indicative of a mafic igneous protolith. Dark grey luminescent overgrowth rims contain the coesite eclogite-facies mineral inclusion assemblage Coe+Grt+Omp+Phe+Ap, and formed at T=732–839°C and P=3.0–4.0GPa. In contrast, white luminescent small clear zircons preserve mineral inclusions formed during retrograde HP quartz eclogite to LP amphibolite-facies metamorphism (T=612–698°C and P=0.70–1.05GPa). Inherited zircons from both samples yield SHRIMP 206Pb/238U ages of 695–520Ma with an upper intercept age of 800±31Ma. The UHP rims yield consistent Triassic ages around 236–225 and 239–225Ma for G12 and G13 with weighted means of 229±3 and 231±3Ma, respectively. Small clear zircons from both samples give 206Pb/238U ages around 219–210Ma with a weighted mean of 214±3Ma, interpreted as the age of retrograde quartz eclogite-facies metamorphism. Matrix amphibole from both samples indicate Ar–Ar ages of 209±0.7 and 207±0.7Ma, respectively, probably dating late amphibolite-facies retrogression. The data suggest subduction of Neoproterozoic mafic igneous rocks to UHP conditions in Middle Triassic (∼230Ma) times and subsequent exhumation to an early HP (∼214Ma) and a late LP stage (∼208Ma) over a period of ∼16 and 6Myr, respectively. Thus, early exhumation from a mantle depth of 120–100km to about 60km occurred at an average rate of 0.3cm/y, while subsequent exhumation to a middle crustal level took place at approximately 0.54cm/y. These exhumation rates are considerably slower than those obtained for UHP rocks in the Dora Maira and Kokchetav massifs (2–3cm/y). Based on similar P–T estimates and trace element and Hf isotope compositions, Sulu amphibolites can be identified as retrograde UHP eclogites. The εHf(800) of +8 implies a significant input from the depleted mantle to the Sulu–Dabie terrane during the middle Neoproterozoic. Overgrown rims are characterized by a distinct trace element composition with low Lu/Hf and Th/U and significantly higher 176Hf/177Hf ratios than inherited cores, consistent with formation during/after garnet (re-)crystallization and fractionation of the Lu–Hf system during UHP metamorphism. The combined dataset suggests homogenization of the 176Hf/177Hf ratio within the metamorphic mineral assemblage and during protolith formation. Observed variations are explained by mixing of material from both domains during laser ablation, e.g., due to partial recrystallization of inherited cores. 2008 0016-7037 https://doi.org/10.1016/j.gca.2008.04.007 Geochimica et Cosmochimica Acta 72 2973-3000 12 https://www.sciencedirect.com/science/article/pii/S0016703708001804 Fulai Liu Axel Gerdes Lingsen Zeng Huaimin Xue article Ferrière20081678 Shock wave attenuation rate and formation of central uplifts are not precisely constrained for moderately sized complex impact structures. The distribution of shock metamorphism in drilled basement rocks from the 10.5-kilometer-diameter Bosumtwi crater, and results of numerical modeling of inelastic rock deformation and modification processes during uplift, constrained with petrographic data, allowed reconstruction of the pre-impact position of the drilled rocks and revealed a shock attenuation by ∼5 gigapascals in the uppermost 200 meters of the central uplift. The proportion of shocked quartz grains and the average number of planar deformation feature sets per grain provide a sensitive indication of minor changes in shock pressure. The results further imply that for moderately sized craters the rise of the central uplift is dominated by brittle failure. Article 2008 English 10959203 10.1126/science.1166283 Science 322 1678 – 1681 5908 crater; deformation; numerical model; pressure; quartz; shock metamorphism; shock wave; uplift; article; calculation; Craterostigma; crystallography; priority journal; rock; scientific literature; shock wave https://www.scopus.com/inward/record.uri?eid=2-s2.0-58149236488&doi=10.1126%2fscience.1166283&partnerID=40&md5=decfce110c6880314dfe3592ce7c02a1 Cited by: 43 Ludovic Ferrière Christian Koeberl Boris A. Ivanov Wolf Uwe Reimold article Wiersberg20081675 Data are presented on the molecular composition of drill-mud gas from the lower sedimentary section (1800-3987 m) of the SAFOD (San Andreas Fault Observatory at Depth) Main Hole measured on-line during drilling, as well as C and H isotope data from off-line mud gas samples. Hydrocarbons, H2 and CO2 are the most abundant non-atmospheric gases in drill-mud when drilling seismogenic zones. Gas influx into the well at depth is related to the lithology and permeability of the drilled strata: larger formation gas influx was detected when drilling through organic-rich shales and permeable sandstones. The SAF (San Andreas Fault), encountered between approximately 3100 m and 3450 m borehole depth, is generally low in gas, but is encompassed by two gas-rich zones (2700-2900 m and below 3550 m) at the fault margins with enhanced 222Rn activities and distinct gas compositions. Within the fault, two interstratified gas-rich lenses (3150-3200 m and 3310-3340 m) consist of CO2 and hydrocarbons (upper zone), but almost exclusively of hydrocarbons (lower zone). The isotopic composition indicates an organic source of hydrocarbons and CO2 in the entire sedimentary section of the well. Hydrocarbons in sedimentary strata are partly of microbial origin down to ∼2500 m borehole depth. The contribution of thermogenic gas increases between ∼2500 m and 3200 m. Below ∼3200 m, hydrocarbons fully derive from thermal degradation of organic matter. The lack of H2 in the center of the fault and the high concentration of H2 in the fractured zones at the fault margins are consistent with H2 formation by interaction of water with fresh silica mineral surfaces generated by tectonic activities, however, this needs to be verified by laboratory experiments. Based on these studies, it is concluded that the fault zone margins consist of strata with enhanced permeability, separated by a low-permeability fault center. © 2008 Elsevier Ltd. All rights reserved. 2008 English 08832927 10.1016/j.apgeochem.2008.01.012 Applied Geochemistry 23 1675-1690 GeoForschungsZentrum Potsdam, Telegrafenberg, 14473 Potsdam, Germany 6 Boreholes; Drilling; Gas fuel analysis; Hydrocarbons; Sedimentation, Gas compositions; Seismogenic zones; Spatial distribution, Seismographs, analytical method; chemical composition; concentration (composition); gas; hydrocarbon; isotopic composition; measurement method; permeability; sandstone; seismic zone; spatial distribution, California; North America; San Andreas Fault Zone; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-44149122181&doi=10.1016%2fj.apgeochem.2008.01.012&partnerID=40&md5=226dc21ae4a0b197f92f5597bf9c2eb1 cited By 64 T. Wiersberg J. Erzinger article Fischer2008493 We present the pattern of seismic activity in the period between 2001 and 2007 for the Novä Kostel focal zone, which is recently the most active zone of the West-Bohemia/Vogtland earthquake swarm region. While the year 2001 was characterized by dying out of the 2000-swarm activity in the form of a few microswarms, almost no seismicity occurred in the period between 2002 and 2003. Since 2004 an elevated seismic activity occurs in the form of repeating microearthquake swarms. We used a relative location method to relate the hypocenter positions of the post-swarm activity to the geometry of the 2000-swarm cluster. We found that the activity has concentrated in several clusters, which have been repeatedly activated. Some clusters coincide with the position of the previous activity; the others have activated so far inactive deep segments at the southern edge of the Novä Kostel fault. Besides the shift of the hypocenters to the edges of the previously active area we observe a southward migration of the activity and an increase of maximum depths of earthquakes from 10 to 13 km. The waveform similarity analysis disclosed that some fault patches consist of only a single, repeatedly activated fault plane, while the others consist of multiple, differently oriented fault planes activated almost simultaneously. Most of the focal mechanisms are consistent with the geometry of hypocenters showing NNW-SSE trending steep fault planes with left-lateral strike-slip mechanisms and varying dip-slip component. © Institute of Geophysics of the ASCR, v.v.i 2008. Article 2008 English 00393169 10.1007/s11200-008-0034-y Studia Geophysica et Geodaetica 52 Springer New York 493 – 512 4 earthquake hypocenter; earthquake swarm; microearthquake; seismic migration; seismicity; strike-slip fault; waveform analysis https://www.scopus.com/inward/record.uri?eid=2-s2.0-57549117787&doi=10.1007%2fs11200-008-0034-y&partnerID=40&md5=467388ff248f37cae39cf937fd0e1676 Cited by: 40 T. Fischer J. Michálek article Fujimitsu200835 Drilling of the volcanic conduit in the Unzen Scientific Drilling Project (USDP) was completed in 2004. Some conduit materials of the 1990-95 eruption were encountered at the bottom of Well USDP-4 (150 m below sea level), and a bottom temperature of about 200 °C was estimated using logging data, although before drilling a temperature of about 700 °C had been inferred. Accordingly, conduit cooling from the initial temperature (850 °C) to the estimated temperature (about 200 °C) was evaluated by numerical simulation. The drilling provides constraints for the numerical model. The drilling indicates that the N-S width of the conduit of the latest eruption is 20 to 30 m and that it occupies a zone of about 300 m, which includes conduits of past eruptions. The process of cooling in the conduit, from an initial temperature of 850 °C in 1995 (the end of the eruption) to 200 °C in 2004 (completion of the conduit drilling), was replicated in models with permeabilities of 1 and 10 mdarcys. This result demonstrates that a highly permeable volcanic body surrounding a small conduit is required to explain the estimated bottom temperature. Our study also aimed to use a numerical simulation to construct a comprehensive hydrothermal model beneath Unzen Volcano. There are four large geothermal systems in the Shimabara Peninsula (Obama hot springs, Unzen fumarolic field, Shimabara hot springs and the West Unzen High Temperature Body [WUHTB]). Three pressure sources ("Sources A", "B" and "C" from shallow to the deep) were determined by geodetic data during the 1990-95 eruption. Source C is located at about 8 km deep at WUHTB, and is considered to be a magma body. We attempted to explain the existence of the four geothermal systems from the large-scale structures (the topography of the Shimabara Peninsula and Unzen Graben) and the various heat sources. We first set a heat source around Source C and changed its position and size. This numerical model produced the upflow zones at the Obama and Shimabara hot springs and WUHTB; however, the Unzen fumarolic field became a recharge area. This result indicates that another heat source is required to explain the Unzen fumarolic field and that two heat sources beneath WUHTB and the Unzen fumarolic field are involved in the formation of the four hydrothermal systems in the Shimabara Peninsula. © 2008 Elsevier B.V. All rights reserved. 2008 English 03770273 10.1016/j.jvolgeores.2008.03.032 Journal of Volcanology and Geothermal Research 175 35-44 Faculty of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan; Graduate School of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan 1-2 Computer simulation; Cooling; Drilling; Estimation; Geothermal fields; Geothermal prospecting; Geothermal springs; Geothermal wells; Hot springs; Landforms; Numerical methods; Oceanography; Offshore oil well production; Offshore oil wells; Oil well logging; Sea level; Springs (components); Temperature; Volcanic rocks; Volcanoes; Water levels; Well logging, Bottom temperature; Fumarolic field; Geodetic data; geothermal fluid; Geothermal systems; heat source; Heat sourcing; High temperature; Hydro-thermal systems; hydrothermal system; Initial temperature; Large-scale structures; Logging data; numerical model; Numerical modelling; Numerical simulations; Recharge area; Shimabara Peninsula; Unzen Volcano; Volcanic conduits, Well drilling, heat source; hydrothermal fluid; hydrothermal system; magma; numerical model; thermal spring; volcanic eruption, Asia; Eurasia; Far East; Japan; Kyushu; Nagasaki [Kyushu]; Shimabara Peninsula; Unzen Volcano https://www.scopus.com/inward/record.uri?eid=2-s2.0-50049122949&doi=10.1016%2fj.jvolgeores.2008.03.032&partnerID=40&md5=8bb420787441578149fd894cb91982b9 cited By 7 Y. Fujimitsu S. Ehara R. Oki R. Kanou article Albrecht2008157 Ancient sister lakes are considered to be ancient lakes lying in close geographic proximity, sharing a related origin and significant time of co-existence, usually having hydrological connection as well as a balanced degree of faunal overlap and distinctness. A paradigm for studying sister lake relationships are the ancient lakes Ohrid and Prespa in the Balkans, which are characterized by high degrees of endemicity. Three general patterns of endemic species can be distinguished for these lakes: (1) taxa that are endemic to either lake, with no close relatives in the respective sister lake, (2) closely related but distinct endemic taxa in both lakes (sister species) and (3) shared endemic taxa occurring in both lakes. In the present paper, two endemic freshwater pulmonate gastropod species, Radix relicta (Lake Ohrid) and R. pinteri (Lake Prespa), are used to study the evolution of presumed sister species based on biogeographical and comparative DNA data from world-wide Radix taxa. Phylogenetic, phylogeographical and parametric bootstrap analyses all suggest a sister group relationship of R. relicta and R. pinteri (pattern 2 of endemic diversity). Sister to these two taxa is the widespread R. ampla, which does not occur in the vicinity of lakes Ohrid and Prespa. The southern feeder spring complexes of Lake Ohrid are inhabited by another lineage (Radix sp. 1), which resembles Radix relicta in morphology/anatomy. For Lake Prespa, the widespread R. auricularia was reported in addition to the endemic R. pinteri. Comparative phylogenetic data favour a western Adriatic zoogeographical affinity of lakes Ohrid and Prespa over an Aegean-Anatolian faunal connection. The status of lakes Ohrid and Prespa as sister lakes is evaluated in the light of current knowledge on gastropod speciation and endemism in these hotspots of biodiversity. © 2008 Springer Science+Business Media B.V. Conference paper 2008 English 15735117 10.1007/s10750-008-9555-1 Hydrobiologia 615 157 – 167 1 Eurasia; Europe; Lake Mikri Prespa; Lake Ohrid; Southern Europe; Gastropoda; Radix (gastropod); Radix ampla; Radix auricularia; Radix sp.; Biodiversity; Nucleic acids; Organic acids; biodiversity; DNA; endemic species; evolution; freshwater ecosystem; gastropod; lake; phylogenetics; taxonomy; Ancient lake; Balkan; Lake Ohrid; Lake Prespa; Radix; Sister lakes; Lakes https://www.scopus.com/inward/record.uri?eid=2-s2.0-53649106181&doi=10.1007%2fs10750-008-9555-1&partnerID=40&md5=1d6e53f6ed1a125d788916b702e4ac21 Cited by: 67 Christian Albrecht Christian Wolff Peter Glöer Thomas Wilke article Sakuma20081 Borehole USDP-4 was drilled into the Unzen volcanic conduit 9 years after its last eruption. The sub-surface mechanism of eruption at Unzen Volcano was investigated by taking cores and by geophysical logging. The drilling operations were carried out in 2003-04, as a joint research program sponsored by the Japanese Government and the International Continental Scientific Drilling Program (ICDP). Borehole USDP-4 was a directional 6-1/4 in. (158.8 mm) borehole drilled from a site located on the northern slope of the volcano at 840 m above sea level, and was designed to penetrate into the conduit at sea level with a final deviation angle of over 70° from vertical and a borehole depth of 1800 m. An igneous dyke with a high likelihood of being the Unzen conduit was encountered at 1996 m depth and core samples were taken from that location. Chemical analysis of drill cores confirmed the identification of the conduit. Geophysical logging, including recording of gamma ray, resistivity, self-potential, density, neutron porosity, sonic velocity, and temperature suggested an alternation of dykes and flows in rock penetrated during the drilling, and in-hole pictures confirmed the lithologic identifications. Although borehole collapse and high temperature had been expected in the conduit, the actual drilling and logging into the conduit experienced no gas or fluid kick, and the measured temperatures within the dyke were below 200 °C. © 2008 Elsevier B.V. All rights reserved. 2008 English 03770273 10.1016/j.jvolgeores.2008.03.039 Journal of Volcanology and Geothermal Research 175 1-12 Japan Metals and Chemicals Co., Ltd. (Japan), 101-1 Hosoyachi, Ukai, Takizawa, Iwate, 020-0172, Japan; Volcano Research Center, Earthquake Research Institute, University of Tokyo (Japan), 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-0032, Japan; National Institute of Advanced Industrial Science and Technology (Japan), Central 7, Tsukuba, Ibaraki, 305-8567, Japan; Institute of Seismology and Volcanology, Kyushu University (Japan), 2-5643-29 Shin'yama, Shimabara, Nagasaki, 855-0843, Japan 1-2 Acoustic logging; Core drilling; Drilling; Forestry; Gamma rays; Geophysics; Harvesting; Ionizing radiation; Landforms; Logging (forestry); Neutron logging; Oceanography; Offshore oil wells; Rock drilling; Sea level; Volcanic rocks; Volcanoes; Water levels, Bore hole; Chemical-; Deviation angles; Drilling operations; extended reach borehole; Geophysical logging; High temperature; Neutron porosity; Research programs; scientific drilling; Self-potential; Sonic velocity; spot coring; Surface mechanism; tough logging; volcanic conduit; Volcanic conduits, Boreholes, borehole logging; chemical analysis; dike; geophysical survey; volcanic eruption, Drilling; Forestry; Gamma Rays; Harvesting; Ionizing Radiation; Logging; Oceanography; Volcanism; Water, Asia; Eurasia; Far East; Japan; Kyushu; Nagasaki [Kyushu]; Unzen Volcano https://www.scopus.com/inward/record.uri?eid=2-s2.0-50049107821&doi=10.1016%2fj.jvolgeores.2008.03.039&partnerID=40&md5=b969afce5b6898cd3ae0762f6c1bcc69 cited By 33 S. Sakuma T. Kajiwara S. Nakada K. Uto H. Shimizu article Vasconcelos2008349 2008 English 00963941 10.1029/2008EO380001 Eos 89 Blackwell Publishing Ltd 349 Colorado School of Mines, Golden, United States; Earth and Ocean Sciences Division, Duke University Durham, NC, United States; Paulsson Geophysical Services, Inc., Brea, CA, United States 38 drill bit; fault; noise; San Andreas Fault, California; North America; San Andreas; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-67649497579&doi=10.1029%2f2008EO380001&partnerID=40&md5=144f0f9cc5508ec703d2a83786010b40 cited By 6 I. Vasconcelos R. Snieder P. Sava T. Taylor P. Maun A. Chavarria article Gohn20081740 Samples from a 1.76-kilometer-deep corehole drilled near the center of the late Eocene Chesapeake Bay impact structure (Virginia, USA) reveal its geologic, hydrologic, and biologic history. We conducted stratigraphic and petrologic analyses of the cores to elucidate the timing and results of impact-melt creation and distribution, transient-cavity collapse, and ocean-water resurge. Comparison of post-impact sedimentary sequences inside and outside the structure indicates that compaction of the crater fill influenced long-term sedimentation patterns in the mid-Atlantic region. Salty connate water of the target remains in the crater fill today, where it poses a potential threat to the regional groundwater resource. Observed depth variations in microbial abundance indicate a complex history of impact-related thermal sterilization and habitat modification, and subsequent post-impact repopulation. 2008 10.1126/science.1158708 Science 320 1740-1745 U.S. Geological Survey, Reston, VA 20192, United States; Department of Lithospheric Research, Center for Earth Sciences, University of Vienna, Althanstrasse 14, Vienna A-1090, Austria; Department of Geological Sciences, Rutgers University, 610 Taylor Road, Piscataway, NJ 08854, United States; Museum of Natural History (Mineralogy), Humboldt-University Berlin, Invalidenstrasse 43, Berlin 10115, Germany; Centre for Earth, Planetary, Space, and Astronomical Research, Open University, Milton Keynes MK7 6AA, United Kingdom 5884 https://www.scopus.com/inward/record.uri?eid=2-s2.0-46449110214&doi=10.1126%2fscience.1158708&partnerID=40&md5=cb49fd084b10d1cb6073d9c85b47ff28 cited By 92 G.S. Gohn C. Koeberl K.G. Miller W.U. Reimold J.V. Browning C.S. Cockell J.W. Horton Jr. T. Kenkmann A.A. Kulpecz D.S. Powars W.E. Sanford M.A. Voytek article Gohn20081740 Samples from a 1.76-kilometer-deep corehole drilled near the center of the late Eocene Chesapeake Bay impact structure (Virginia, USA) reveal its geologic, hydrologic, and biologic history. We conducted stratigraphic and petrologic analyses of the cores to elucidate the timing and results of impact-melt creation and distribution, transient-cavity collapse, and ocean-water resurge. Comparison of post-impact sedimentary sequences inside and outside the structure indicates that compaction of the crater fill influenced long-term sedimentation patterns in the mid-Atlantic region. Salty connate water of the target remains in the crater fill today, where it poses a potential threat to the regional groundwater resource. Observed depth variations in microbial abundance indicate a complex history of impact-related thermal sterilization and habitat modification, and subsequent post-impact repopulation. 2008 English 00368075 10.1126/science.1158708 Science 320 1740-1745 U.S. Geological Survey, Reston, VA 20192, United States; Department of Lithospheric Research, Center for Earth Sciences, University of Vienna, Althanstrasse 14, Vienna A-1090, Austria; Department of Geological Sciences, Rutgers University, 610 Taylor Road, Piscataway, NJ 08854, United States; Museum of Natural History (Mineralogy), Humboldt-University Berlin, Invalidenstrasse 43, Berlin 10115, Germany; Centre for Earth, Planetary, Space, and Astronomical Research, Open University, Milton Keynes MK7 6AA, United Kingdom 5884 sea water, abundance; deep drilling; Eocene; groundwater resource; impact structure; petrology; sedimentary sequence; sedimentation; stratigraphy, article; asthenospheric upwelling; biosphere; controlled study; Cretaceous; drill; hydrology; instrument sterilization; microbial growth; nonhuman; petrology; priority journal; sedimentation; stratigraphy; terrestrial surface waters, Bacteria; Ecosystem; Geologic Sediments; Heat; Salinity; Seawater; Time; Virginia, Chesapeake Bay; North America; United States; Virginia https://www.scopus.com/inward/record.uri?eid=2-s2.0-46449110214&doi=10.1126%2fscience.1158708&partnerID=40&md5=cb49fd084b10d1cb6073d9c85b47ff28 cited By 92 G.S. Gohn C. Koeberl K.G. Miller W.U. Reimold J.V. Browning C.S. Cockell J.W. Horton Jr. T. Kenkmann A.A. Kulpecz D.S. Powars W.E. Sanford M.A. Voytek article Olsen200862 2008 English 18168957 10.2204/lodp.sd.6.12.2008 Scientific Drilling 62-66 Lamont-Doherty Earth Observatory (LDEO), Columbia University, 61 Route 9W, Palisades, NY 10964-1000, United States; Department of Earth and Planetary Sciences, Rutgers University, 610 Taylor Road, Piscataway, NJ 08854, United States; Lamont-Doherty Earth Observatory, 61 Route 9W, Palisades, NY 10964, United States; Department of Earth and Planetary Sciences, University of New Mexico, Albuquerque, NM 87131, United States 6 https://www.scopus.com/inward/record.uri?eid=2-s2.0-78651551909&doi=10.2204%2flodp.sd.6.12.2008&partnerID=40&md5=8165ee0f275da48a79fe178f287963c1 cited By 1 P.E. Olsen D.V. Kent J.W. Geissman article Ishikawa2008679 Aqueous fluids are thought to have an essential role in faulting and the dynamic propagation of earthquake rupture. Fluid overpressure can affect earthquake nucleation and in a process termed thermal pressurization, pore fluid pressure produced by frictional heating can reduce the effective normal stress acting on the fault surface. This may lead to a marked reduction in fault strength during slip. However, the coseismic presence of fluids within slip zones and the role of fluids in dynamic fault weakening is still a matter of debate. Here we present compositions of major and trace elements as well as isotope ratios of core samples representing relatively undamaged as well as very fine-grained deformed material from three active zones of the Chelungpu fault, Taiwan. Depth profiles across the most intensely sheared bands that range in thickness from 2-15 cm exhibit sharp compositional peaks of fluid-mobile elements and of strontium isotopes. We suggest that high-temperature fluids (>350 C) derived from heating of sediment pore fluids during the earthquake interacted with material within the fault zone and mobilized the elements. The coseismic presence of high-temperature fluids under conditions of low hydraulic diffusivity within the fault zone is favourable for thermal pressurization. This effect may have caused a dynamic decrease of friction along the Chelungpu fault during the 1999 magnitude 7.6 Chi-Chi earthquake. © 2008 Macmillan Publishers Limited. 2008 English 17520894 10.1038/ngeo308 Nature Geoscience 1 Nature Publishing Group 679-683 Kochi Institute for Core Sample Research, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 200 Monobe-otsu, Nankoku, Kochi 783-8502, Japan; Marine Works Japan Ltd., Nankoku, Kochi 783-8502, Japan; Department of Earth and Space Science, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan; Research Center for Inland Seas, Kobe University, Kobe, Hyogo 657-8501, Japan; Department of Geosciences, National Taiwan University, Taipei 10617, Taiwan 10 https://www.scopus.com/inward/record.uri?eid=2-s2.0-62749157721&doi=10.1038%2fngeo308&partnerID=40&md5=effd7f30c5fe23b2cde68abed283f104 cited By 105 T. Ishikawa M. Tanimizu K. Nagaishi J. Matsuoka O. Tadai M. Sakaguchi T. Hirono T. Mishima W. Tanikawa W. Lin H. Kikuta W. Soh S.-R. Song article Fritz2008342 Erratum 2008 10.1016/j.yqres.2008.01.004 Quaternary Research 69 342 2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-40949134656&doi=10.1016%2fj.yqres.2008.01.004&partnerID=40&md5=504cbe8b02234e771d4749ccb4f937c0 Cited by: 2; All Open Access, Bronze Open Access Sherilyn C. Fritz Paul A. Baker Geoffrey O. Seltzer Ashley Ballantyne Pedro Tapia Hai Cheng R. Lawrence Edwards article yongyi2008coring 2008 Exploration Engineering (Rock & Soil Drilling and Tunneling) 35 1-5 9 ZHU Yongyi Wang Wenshi article Wu2008949 Taiwan Chelungpu-fault Drilling Project (TCDP) was initiated to understand the physical mechanisms involved in the large displacements of the 1999 Taiwan Chi-Chi earthquake. Continuous measurements of cores (including laboratory work) and a suite of geophysical downhole logs, including P- and S-wave sonic velocity, gamma ray, electrical resistivity, density, temperature, electrical borehole images and dipole-shear sonic imager, were acquired in Hole-A over the depth of 500-2003 m. Integrated studies of cores and logs facilitate qualitative and quantitative comparison of subsurface structures and physical properties of rocks. A total of 10 subunits were divided on the basis of geophysical characteristics. Generally, formation velocity and temperature increase with depth as a result of the overburden and thermal gradient, respectively. Gamma ray, resistivity, formation density, shear velocity anisotropy and density-derived porosity are primarily dependent on the lithology. Zones with changes of percentage of shear wave anisotropy and the fast shear polarization azimuth deduced from Dipole Shear-Imager (DSI) are associated with the appearance of fractures, steep bedding and shear zones. The fast shear wave azimuth is in good agreement with overall dip of the bedding (approximately 30° towards SE) and maximum horizontal compressional direction, particularly in the Kueichulin Formation showing strong shear wave velocity anisotropy. Bedding-parallel fractures are prevalent within cores, whereas minor sets of high-angle, NNW-SSE trending with N- and S-dipping fractures are sporadically distributed. The fault zone at depth 1111 m (FZA1111) is the Chi-Chi earthquake slip zone and could be a fluid conduit after the earthquake. The drastic change in fast shear wave polarization direction across the underlying, non-active Sanyi thrust at depth 1710 m reflects changes in stratigraphy, physical properties and structural geometry. © 2008 The Authors Journal compilation © 2008 RAS. 2008 English 0956540X 10.1111/j.1365-246X.2008.03841.x Geophysical Journal International 174 949-965 Institute of Geophysics, National Central University, Taiwan; Department of Geosciences, National Taiwan University, Taiwan; Institute of Applied Geology, National Central University, Taiwan 3 azimuth; Chi-Chi earthquake 1999; displacement; earthquake mechanism; fault zone; S-wave; seismic anisotropy; seismicity; shear zone, Asia; Eurasia; Far East; Taiwan https://www.scopus.com/inward/record.uri?eid=2-s2.0-50649086610&doi=10.1111%2fj.1365-246X.2008.03841.x&partnerID=40&md5=51c01868c82cd8c7181b65928414feea cited By 22 Y.-H. Wu E.-C. Yeh J.-J. Dong L.-W. Kuo J.-Y. Hsu J.-H. Hung conference Lucier2008 Researchers from The Natural Earthquake Laboratory in South African Mines (NELSAM) project are investigating the physics and mechanics of mining-induced earthquakes using the access to seismogenic depths provided by deep South African gold mines and the large number of seismic events that occur near these mines. To study these events, it is necessary to quantify the far-field stress field around the mine, determine how the presence of the mining excavation perturbs this stress field, and investigate how these mining-induced stress changes affect the pre-existing faults. In this paper, we develop and test a new technique for determining the far-field virgin state of stress near the TauTona gold mine. The technique we used to constrain the far-field stress state follows an iterative forward modeling approach that combines observations of drilling induced borehole failures in borehole images, boundary element modeling of the mining-induced stress perturbations, and forward modeling of borehole failures based on the results of the boundary element modeling. Following this approach, we determined that the state of stress is a normal faulting regime with principal stress orientations that are slightly deviated from vertical and. Modeling of breakout rotations and gaps in breakout occurrence associated with recent fault slip on critically stressed faults further confirmedthis stress state. ©2008, ARMA, American Rock Mechanics Association. Conference paper 2008 English 10.1016/j.ijrmms.2008.09.005 42nd U.S. Rock Mechanics - 2nd U.S.-Canada Rock Mechanics Symposium 46 555 – 567 Shell International Exploration and Production, Inc., Houston, TX, United States; Stanford University, Stanford, CA, United States; University of Oklahoma, Norman, OK, United States 3 African gold mine; Borehole images; Boundary elements; Far-field; Far-field stress; Fault slip; Forward modeling; Induced stress; Insitu stress; Mining excavation; Natural earthquake; Principal stress; Seismic event; State of stress; Stress field; Stress state; Virgin state, Earthquakes; Gold; Gold mines; Mines; Rock mechanics; Rocks; Stresses, Mining https://www.scopus.com/inward/record.uri?eid=2-s2.0-69549103366&partnerID=40&md5=daff1f0e0a34db6a393ad3f05685495b Cited by: 0 A.M. Lucier M.D. Zoback V. Heesakkers Z. Reches article Almberg200860 Core samples from the conduit of Unzen Volcano, obtained only 9 years after cessation of the 1991-1995 eruption, exhibit important differences in physical characteristics and mineralogy, and subtle differences in bulk chemistry from erupted samples. These differences in the conduit samples reflect emplacement under a confining pressure where about half of the original magmatic water was retained in the melt phase, maintenance at hypersolidus temperature for some unknown but significant time span, and subsequent subsolidus hydrothermal alteration. In contrast, magma that extruded as lava underwent decompression to 1 atm with nearly complete loss of magmatic water and cooling at a sufficiently rapid rate to produce glass. The resulting hypabyssal texture of the conduit samples, while clearly distinct from eruptive rocks, is also distinct from plutonic suites. Given the already low temperature of the conduit (less than 200 °C, [Nakada, S., Uto, K., Yoshimoto, M., Eichelberger, J.C., Shimizu, H., 2005. Scientific Results of Conduit Drilling in the Unzen Scientific Drilling Project (USDP), Sci. Drill., 1, 18-22]) when it was sampled by drilling, this texture must have developed within a decade, and perhaps within a much shorter time, after emplacement. The fact that all trace-element concentrations of the conduit and the last-emplaced lava of the spine, 1300 m above it, are identical to within analytical uncertainty provides strong evidence that both were produced during the same eruption sequence. Changes in conduit magma that occurred between emplacement and cooling to the solidus were collapse of vesicles from less than or equal to the equilibrium value of about 50 vol.% to about 0.1 vol.%; continued resorption of quartz and reaction of biotite phenocrysts due to heating of magma prior to ascent by intruding mafic magma; breakdown of hornblende; and micro-crystallization of rhyolitic melt to feldspar and quartz. Subsolidus changes were deposition of calcite and pyrite, growth of sericite in anorthite-rich zones of plagioclase, and development of montmorillonite as an alteration product. Significant changes in bulk composition were depletion of Mg, Fe and Na and enrichment in C and S. These changes were due mainly to the breakdown of hornblende and plagioclase, and addition of carbonate and pyrite, respectively. The identical concentrations of REEs in the conduit and surface lava are consistent with low water to rock ratios during alteration. This suggests to us that despite convective hydrothermal removal of heat from the conduit, chemical open-system effects were limited to early loss of magmatic water and later addition of magmatic CO2 and SO2 and/or H2S streaming up the conduit from deeper levels. © 2008 Elsevier B.V. 2008 English 03770273 10.1016/j.jvolgeores.2008.03.020 Journal of Volcanology and Geothermal Research 175 60-70 University of Alaska Fairbanks Geophysical Institute, Fairbanks, AK 99775, United States; Michigan State University, Department of Geological Sciences, East Lansing, MI 48824, United States 1-2 Calcite; Carbonate minerals; Clay minerals; Cooling; Crystallography; Dewatering; Drilling; Feldspar; Heating; Landforms; Lithology; Metallic glass; Mica; Mineralogy; Minerals; Ore deposit geology; Oxide minerals; Physical chemistry; Product development; Pyrites; Quartz; Rate constants; Silicate minerals; Sodium; Sulfate minerals; Textures; Trace elements; Volcanic rocks; Volcanoes, Analytical uncertainties; Bulk compositions; Chemical-; Confining pressures; crystallization texture; decompression experiments; Element concentrations; Equilibrium value; Hydrothermal alterations; Low temperature; Magmatic water; Melt phase; phase equilibria; Physical characteristics; Plutonic suites; Pressure-temperature-time paths; Rapid rate; Rhyolitic; Scientific results; Sericite; Subsolidus; System effects; Time span; Unzen; vesicularity, Cooling water, confining pressure; drilling; emplacement; hydrothermal alteration; igneous intrusion; lava; magmatic differentiation; phase equilibrium; trace element; volcanic eruption, Asia; Eurasia; Far East; Japan; Kyushu; Nagasaki [Kyushu]; Unzen Volcano https://www.scopus.com/inward/record.uri?eid=2-s2.0-50049092347&doi=10.1016%2fj.jvolgeores.2008.03.020&partnerID=40&md5=fdb618dad80322b624d97b564553927c cited By 8 L.D. Almberg J.F. Larsen J.C. Eichelberger T.A. Vogel L.C. Patino article dresen2008drilling 2008 English 18168957 10.2204/lodp.sd.6.10.2008 Scientific Drilling 6 ICDP-IODP Göttingen, Germany 58-59 GeoForschungsZentrum Potsdam, Telegrafenberg D-14473 Potsdam, Germany; Bogaziel University, Kandilli Observatory and Earthquake Research Institute (KOERI), Cangelkoy, Istanbul 81220, Turkey; Istanbul Technical University, Mining Faculty, Department of Geophysics, 3469 Maslak Istanbul, Turkey 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-78651545000&doi=10.2204%2flodp.sd.6.10.2008&partnerID=40&md5=509f8884df17cc1ac492c5de9ca20cbd cited By 3 Georg Dresen Marco Bohnhoff Mustafa Aktar Haluk Eyidogan article Schulte2008614 2008 10.1016/j.epsl.2007.11.066 Earth and Planetary Science Letters 269 614-620 Institut für Geologie und Mineralogie, Universität Erlangen, Schlossgarten 5, D-91054 Erlangen, Germany; Department of Geography-Geology, K.U.Leuven, Celestijnenlaan 200E, B-3001 Leuven, Belgium; Institute of Environmental Biology (IEB), Laboratory of Palaeobotany and Palynology, Utrecht University, Budapestlaan 4, 3584 CD Utrecht, Netherlands; Geologisch-Paläontologisches Institut, Universität Heidelberg, Im Neuenheimer Feld 234, D-69120 Heidelberg, Germany; Department of Geology, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium; Istituto di Scienze della Terra, Università degli Studi di Urbino, Campus Scientifico, Localita Crocicchia, 61029 Urbino, Italy; Sedimentology Group, Vrije Universiteit, de Boelelaan 1085, 1081 HV Amsterdam, Netherlands 3-4 https://www.scopus.com/inward/record.uri?eid=2-s2.0-43249094377&doi=10.1016%2fj.epsl.2007.11.066&partnerID=40&md5=94b61551ad046cc3716fdf8d310c93ed cited By 13 P. Schulte R.P. Speijer H. Brinkhuis A. Kontny P. Claeys S. Galeotti J. Smit article https://doi.org/10.1029/2008EO120003 A workshop was convened in St. George, Utah, to advance planning for the Colorado Plateau Coring Project (CPCP). The vast continental basins of the southwestern United States, particularly well exposed on the Colorado Plateau and its environs, contain one of the richest stratigraphic records of early Mesozoic age (between roughly 145 and 250 million years ago). This time period was punctuated by two of the major mass extinctions in the past 550 million years and witnessed the evolutionary appearance of the modern biota and dramatic climate changes on the continents. Since the mid-nineteenth century, classic studies of these basins, their strata, and their fossils have made this sequence instrumental in framing our context for the early Mesozoic world. Nonetheless, striking ambiguities in temporal resolution, uncertainties in global correlations with other early Mesozoic strata, and major doubts about latitudinal position still hamper testing of the major competing climatic, biotic, and tectonic hypotheses. 2008 https://doi.org/10.1029/2008EO120003 Eos, Transactions American Geophysical Union 89 118-118 12 https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2008EO120003 Paul E. Olsen Dennis V. Kent John W. Geissman article Rubino2008 This paper studies the energy conversions that take place at discontinuities within gas hydrate-bearing sediments and their influence on the attenuation of waves traveling through these media. The analysis is based on a theory recently developed by some of the authors, to describe wave propagation in multiphasic porous media composed of two solids saturated by a single-phase fluid. Real data from the Mallik 5L-38 Gas Hydrate Research well are used to calibrate the physical model, allowing to obtain information about the characteristics of the cementation between the mineral grains and gas hydrates for this well. Numerical experiments show that, besides energy conversions to reflected and transmitted classical waves, significant fractions of the energy of propagating waves may be converted into slow-waves energy at plane heterogeneities within hydrated sediments. Moreover, numerical simulations of wave propagation show that very high levels of attenuation can take place in the presence of heterogeneous media composed of zones with low and high gas hydrate saturations with sizes smaller or on the order of the wavelengths of the fast waves at sonic frequencies. These attenuation levels are in very good agreement with those measured at the Mallik 5L-38 Gas Hydrate Research Well, suggesting that these scattering-type effects may be a key-parameter to understand the high sonic attenuation observed at gas hydrate-bearing sediments. Copyright 2008 by the American Geophysical Union. 2008 English 21699313 10.1029/2006JB004871 Journal of Geophysical Research: Solid Earth 113 Blackwell Publishing Ltd CONICET, Facultad de Ciencias Astronómicas y Geofisicas, Universidad Nacional de La Plata, Paseo del Bosque S/N, B1900FWA La Plata, Argentina; Department of Mathematics, Purdue University, West Lafayette, IN, United States 6 Biot theory; experimental study; gas hydrate; heterogeneous medium; numerical model; porous medium; single-phase flow; wave attenuation; wave propagation; wavelength https://www.scopus.com/inward/record.uri?eid=2-s2.0-50649120353&doi=10.1029%2f2006JB004871&partnerID=40&md5=515755fffbabad8e7c13506f32a6c7dd cited By 5 J.G. Rubino C.L. Ravazzoli J.E. Santos article Heim2008567 Web-based Geographical Information Systems (GIS) are excellent tools within interdisciplinary and multi-national geoscience projects to exchange and visualize project data. The web-based GIS presented in this paper was designed for the paleolimnological project 'High-resolution CONTINENTal paleoclimate record in Lake Baikal' (CONTINENT) (Lake Baikal, Siberia, Russia) to allow the interactive handling of spatial data. The GIS database combines project data (core positions, sample positions, thematic maps) with auxiliary spatial data sets that were downloaded from freely available data sources on the world wide web. The reliability of the external data was evaluated and suitable new spatial datasets were processed according to the scientific questions of the project. GIS analysis of the data was used to assist studies on sediment provenance in Lake Baikal, or to help answer questions such as whether the visualization of present-day vegetation distribution and pollen distribution supports the conclusions derived from palynological analyses. The refined geodata are returned back to the scientific community by using online data publication portals. Data were made citeable by assigning persistent identifiers (DOI) and were published through the German National Library for Science and Technology (TIB Hannover, Hannover, Germany). © 2007 Springer Science+Business Media B.V. Article 2008 English 09212728 10.1007/s10933-007-9131-0 Journal of Paleolimnology 39 567 – 584 4 Eurasia; Lake Baikal; Russian Federation; catchment; data set; GIS; paleoclimate; paleolimnology; palynology; plant; population distribution https://www.scopus.com/inward/record.uri?eid=2-s2.0-42149153838&doi=10.1007%2fs10933-007-9131-0&partnerID=40&md5=37a7fab609ed4b7c181872431237a5e2 Cited by: 6; All Open Access, Green Open Access Birgit Heim Jens Klump Hedi Oberhänsli Nathalie Fagel article Escala20081777 Meteorite impacts are associated with locally profound effects for microorganisms living at the terrestrial surface and the subsurface of the impact zone. The Bosumtwi crater in Ghana (West Africa) is a relatively young (1.07 Myr) structure with a rim-to-rim diameter of about 10.5 km. In a preliminary study targeting the subsurface microbial life in the impact structure, seven samples of the impact breccia from the central uplift of the Bosumtwi crater were analyzed for the presence of typical archaeal membrane-lipids (GDGTs). These have been detected in four of the samples, at a maximum depth of 382 m below the lake surface, which is equivalent to 309 m below the surface sediment. The concentration of the GDGTs does not show a trend with depth, and their distribution is dominated by GDGT-O. Possible origins of these lipids could be related to the soils or rocks predating the impact event, the hydrothermal system generated after the impact, or due to more recent underground water transport. © The Meteoritical Society, 2008. Article 2008 English 10869379 10.1111/j.1945-5100.2008.tb00642.x Meteoritics and Planetary Science 43 University of Arkansas 1777 – 1782 11 https://www.scopus.com/inward/record.uri?eid=2-s2.0-61849165483&doi=10.1111%2fj.1945-5100.2008.tb00642.x&partnerID=40&md5=176bd66cafc5c8bc8f6b293e31640de5 Cited by: 2; All Open Access, Bronze Open Access Marina Escala Antoni Rosell-Melé Susanne Fietz Christian Koeberl article 2008 Petroleum Drilling Techniques 36 54-57 5 J. Cai X. Wu Y. Zhu S. Gu X Li W. Wang article Albrecht2008103 Worldwide ancient lakes have been a major focal point of geological, biological, and ecological research, and key concepts in, for example, evolutionary biology are partly based on ancient lake studies. Ancient lakes can be found on most continents and climate zones with most actual or putative ancient lakes in Europe being restricted to the Balkan Region. The arguably most outstanding of them is the oligotrophic and karstic Lake Ohrid, a steep-sided graben of rift formation origin situated in the central Balkans. Here, an attempt is made to summarize current knowledge of the geological, limnological, and faunal history of Lake Ohrid. Additionally, existing data on biodiversity and endemism in Lake Ohrid are updated and evaluated, and patterns and processes of speciation are reviewed in the context of the Ohrid watershed, including its sister lake, Lake Prespa. Whereas the geological history of the Ohrid Graben is relatively well studied, there is little knowledge about the limnological and biotic history of the actual lake (e.g., the age of the extant lake or from where the lake first received its water, along with its first biota). Most workers agree on a time frame of origin for Lake Ohrid of 2-5 million years ago (Mya). However, until now, the exact limnological origin and the origin of faunal or floral elements of Lake Ohrid remain uncertain. Two largely contrasting opinions either favour the theory of de novo formation of Lake Ohrid in a dry polje with a spring or river hydrography or a palaeogeographical connection of Lake Ohrid to brackish waters on the Balkan Peninsula. Whereas neither theory can be rejected at this point, the data summarized in the current review support the de novo hypothesis. An assessment of the fauna and flora of Lake Ohrid confirms that the lake harbours an incredible endemic biodiversity. Despite the fact that some biotic groups are poorly studied or not studied at all, approximately 1,200 native species are known from the lake, including 586 animals, and at least 212 species are endemic, including 182 animals. The adjusted rate of endemicity is estimated at 36% for all taxa and 34% for Animalia. In terms of endemic biodiversity, Lake Ohrid is with these 212 known endemic species and a surface area of 358 km2 probably the most diverse lake in the world, taking surface area into account. Preliminary phylogeographical analyses of endemic Lake Ohrid taxa indicate that the vast majority of respective sister taxa occurs in the Balkans and that therefore the most recent common ancestors of Ohrid- and non-Ohrid species likely resided in the region when Lake Ohrid came into existence. These data also indicate that there is relatively little faunal exchange and overlap between Lake Ohrid and its sister lake, Lake Prespa, despite the fact that the latter lake is a major water supplier for Lake Ohrid. Studies on selected species flocks and scatters, mostly in molluscs, point towards the assumption that only few lineages originally colonized Lake Ohrid from the Balkans and that the majority of endemic species seen today probably started to evolve within the lake during the early Pleistocene. Within the Ohrid watershed, endemism occurs at different spatial and taxonomic scales, ranging from species endemic to certain parts of Lake Ohrid to species endemic to the whole watershed and from subspecies to genus level and possibly beyond. Modes of speciation in the Ohrid watershed are largely affected by its degree of isolation. Observational evidence points towards both allopatric (peripatric) and parapatric speciation. Though sympatric speciation within a habitat is conceivable, so far there are no known examples. Today, the lake suffers from increasing anthropogenic pressure and a "creeping biodiversity crisis". Some endemic species presumably have already gone extinct, and there are also indications of invasive species penetrating Lake Ohrid. The comparatively small size of Lake Ohrid and the extremely small range of many endemic species, together with increasing human pressure make its fauna particularly vulnerable. It is thus hoped that this review will encourage future research on the ecology and evolutionary biology of the lake's taxa, the knowledge of which would ultimately help protecting this unique European biodiversity hot spot. © 2008 Springer Science+Business Media B.V. Conference paper 2008 English 15735117 10.1007/s10750-008-9558-y Hydrobiologia 615 103 – 140 1 Animalia; Mollusca; Mya; Animals; Biodiversity; Offshore oil well production; Rivers; biodiversity; evolution; evolutionary biology; lake; limnology; native species; Pleistocene; speciation (biology); Ancient lake; Balkans; Endemism; Geology; Lake Ohrid; Lake Prespa; Limnology; Sister lakes; Speciation; Lakes https://www.scopus.com/inward/record.uri?eid=2-s2.0-53649084174&doi=10.1007%2fs10750-008-9558-y&partnerID=40&md5=bb7449347c48b5be19d85cc37dbc29d9 Cited by: 190 Christian Albrecht Thomas Wilke article Hodell20081152 Drill cores obtained from Lake Petén Itzá, Petén, Guatemala, contain a ∼85-kyr record of terrestrial climate from lowland Central America that was used to reconstruct hydrologic changes in the northern Neotropics during the last glaciation. Sediments are composed of alternating clay and gypsum reflecting relatively wet and dry climate conditions, respectively. From ∼85 to 48 ka, sediments were dominated by carbonate clay indicating moist conditions during Marine Isotope Stages (MIS) 5a, 4, and early 3. The first gypsum layer was deposited at ∼48 ka, signifying a shift toward drier hydrologic conditions and the onset of wet-dry oscillations. During the latter part of MIS 3, Petén climate varied between wetter conditions during interstadials and drier states during stadials. The pattern of clay-gypsum (wet-dry) oscillations during the latter part of MIS 3 (∼48-23 ka) closely resembles the temperature records from Greenland ice cores and North Atlantic marine sediment cores and precipitation proxies from the Cariaco Basin. The most arid periods coincided with Heinrich Events when cold sea surface temperatures prevailed in the North Atlantic, meridional overturning circulation was reduced, and the Intertropical Convergence Zone (ITCZ) was displaced southward. A thick clay unit was deposited from 23 to 18 ka suggesting deposition in a deep lake, and pollen accumulated during the same period indicates vegetation consisted of a temperate pine-oak forest. This finding contradicts previous inferences that climate was arid during the Last Glacial Maximum (LGM) chronozone (21±2 ka). At ∼18 ka, Petén climate switched from moist to arid conditions and remained dry from 18 to 14.7 ka during the early deglaciation. Moister conditions prevailed during the warmer Bolling-Allerod (14.7-12.8 ka) with the exception of a brief return to dry conditions at ∼13.8 ka that coincides with the Older Dryas and meltwater pulse 1A. The onset of the Younger Dryas at 12.8 ka marked the return of gypsum and hence dry conditions. The lake continued to precipitate gypsum until ∼10.3 ka when rainfall increased markedly in the early Holocene. © 2008 Elsevier Ltd. All rights reserved. Article 2008 English 02773791 10.1016/j.quascirev.2008.02.008 Quaternary Science Reviews 27 1152 – 1165 11-12 Arctic; Atlantic Ocean; Atlantic Ocean (North); Cariaco Basin; Caribbean Sea; Central America; Greenland; Guatemala [Central America]; Lake Peten Itza; Peten; Drilling; Glaciers; Gypsum; Isotopes; Sediments; Soil moisture; climate change; climate conditions; deglaciation; gypsum; Holocene; hydrodynamics; ice core; interstadial; intertropical convergence zone; Last Glacial Maximum; last glaciation; lowland environment; Neotropical region; oceanic circulation; precipitation (chemistry); precipitation intensity; proxy climate record; reconstruction; sediment core; stratigraphy; Younger Dryas; Central America; Drill cores; Terrestrial climate; Climate change https://www.scopus.com/inward/record.uri?eid=2-s2.0-44549085036&doi=10.1016%2fj.quascirev.2008.02.008&partnerID=40&md5=d80ca0680931a5de11cd65199326174c Cited by: 196; All Open Access, Green Open Access David A. Hodell Flavio S. Anselmetti Daniel Ariztegui Mark Brenner Jason H. Curtis Adrian Gilli Dustin A. Grzesik Thomas J. Guilderson Andreas D. Müller Mark B. Bush Alexander Correa-Metrio Jaime Escobar Steffen Kutterolf article Novotný2008123 The western part of the Gulf of Corinth attracts attention due to its seismically active fault system and considerable seismic hazard. Detailed studies of the seismic activity of the region have been carried out especially as part of the so-called Corinth Rift Laboratory (CRL) Project. For standard earthquake locations, the CRL uses the HYPO algorithm and a special structural model that is composed of homogeneous layers (Rigo et al., 1996). This model was derived from a passive seismic experiment in a broader area around the western part of the Gulf. A significant part of the seismic activity is concentrated close to the town of Aigion, which was damaged by a strong earthquake in 1995. A sequence of smaller earthquakes occurred to the south of this town in the year 2001. In the present paper, we have used this sequence to derive an improved structural model for the region in the vicinity of the town of Aigion. This new model is based on the minimization of travel-time residuals. In particular, we used arrival times from a subset of 88 events recorded by at least 5 stations of the southern part of the CRL network, had magnitudes of over 2.3, and were recorded at the nearest station (station code AIO). A variant of the method of conjugate gradients has been used for this purpose. In comparison with the model derived by Rigo et al. (1996), the new model is characterized by a higher νP/νS velocity ratio and by higher velocities to a depth of about 7 km. The new model was derived with the aim to get more accurate locations of future events in the vicinity of the town of Aigion. © Institute of Geophysics of the ASCR, v.v.i 2008. Article 2008 English 00393169 10.1007/s11200-008-0009-z Studia Geophysica et Geodaetica 52 Springer New York 123 – 131 1 Eurasia; Europe; Greece; Gulf of Corinth; Ionian Sea; Mediterranean Sea; Southern Europe; active fault; algorithm; arrival time; crustal structure; earthquake event; gradient analysis; layered medium; modeling; seismic velocity; travel time; upper crust; urban area https://www.scopus.com/inward/record.uri?eid=2-s2.0-43049142664&doi=10.1007%2fs11200-008-0009-z&partnerID=40&md5=62d0601429e322c28584c6bc08d27a9d Cited by: 10 O. Novotný J. Janskü V. Plicka H. Lyon-Caen article Becken2008718 Magnetotelluric (MT) data from 66 sites along a 45-km-long profile across the San Andreas Fault (SAF) were inverted to obtain the 2-D electrical resistivity structure of the crust near the San Andreas Fault Observatory at Depth (SAFOD). The most intriguing feature of the resistivity model is a steeply dipping upper crustal high-conductivity zone flanking the seismically defined SAF to the NE, that widens into the lower crust and appears to be connected to a broad conductivity anomaly in the upper mantle. Hypothesis tests of the inversion model suggest that upper and lower crustal and upper-mantle anomalies may be interconnected. We speculate that the high conductivities are caused by fluids and may represent a deep-rooted channel for crustal and/or mantle fluid ascent. Based on the chemical analysis of well waters, it was previously suggested that fluids can enter the brittle regime of the SAF system from the lower crust and mantle. At high pressures, these fluids can contribute to fault-weakening at seismogenic depths. These geochemical studies predicted the existence of a deep fluid source and a permeable pathway through the crust. Our resistivity model images a conductive pathway, which penetrates the entire crust, in agreement with the geochemical interpretation. However, the resistivity model also shows that the upper crustal branch of the high-conductivity zone is located NE of the seismically defined SAF, suggesting that the SAF does not itself act as a major fluid pathway. This interpretation is supported by both, the location of the upper crustal high-conductivity zone and recent studies within the SAFOD main hole, which indicate that pore pressures within the core of the SAF zone are not anomalously high, that mantle-derived fluids are minor constituents to the fault-zone fluid composition and that both the volume of mantle fluids and the fluid pressure increase to the NE of the SAF. We further infer from the MT model that the resistive Salinian block basement to the SW of the SAFOD represents an isolated body, being 5-8km wide and reaching to depths >7km, in agreement with aeromagnetic data. This body is separated from a massive block of Salinian crust farther to the SW. The NE terminus of resistive Salinian crust has a spatial relationship with a near-vertical zone of increased seismic reflectivity ∼15km SW of the SAF and likely represents a deep-reaching fault zone. © 2008 The Authors Journal compilation © 2008 RAS. 2008 English 0956540X 10.1111/j.1365-246X.2008.03754.x Geophysical Journal International 173 718-732 GeoForschungsZentrum Potsdam, Geophysical Deep Sounding, Telegrafenberg, 14473 Potsdam, Germany; University of California Riverside, Department of Earth Sciences, 2207 Geology, Riverside, CA 92521, United States; US Geological Survey, MS 964, Box 25046, Denver, CO 80225, United States; University Potsdam, Department of Geosciences, Karl-Liebknecht-Strasse 24, 14476 Potsdam, Germany 2 aeromagnetic survey; crustal structure; data interpretation; data inversion; electrical conductivity; electrical resistivity; lower crust; magnetotelluric method; San Andreas Fault; seismic reflection; transform fault; two-dimensional modeling, California; North America; Parkfield; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-42349098421&doi=10.1111%2fj.1365-246X.2008.03754.x&partnerID=40&md5=bf67f788fee28c56e3fd52836b243ef3 cited By 74 M. Becken O. Ritter S.K. Park P.A. Bedrosian U. Weckmann M. Weber article Bauer2008 Crosshole seismic experiments were conducted to study the in-situ properties of gas hydrate bearing sediments (GHBS) in the Mackenzie Delta (NW Canada). Seismic tomography provided images of P velocity, anisotropy, and attenuation. Self-organizing maps (SOM) are powerful neural network techniques to classify and interpret multi-attribute data sets. The coincident tomographic images are translated to a set of data vectors in order to train a Kohonen layer. The total gradient of the model vectors is determined for the trained SOM and a watershed segmentation algorithm is used to visualize and map the lithological clusters with well-defined seismic signatures. Application to the Mallik data reveals four major litho-types: (1) GHBS, (2) sands, (3) shale/coal interlayering, and (4) silt. The signature of seismic P wave characteristics distinguished for the GHBS (high velocities, strong anisotropy and attenuation) is new and can be used for new exploration strategies to map and quantify gas hydrates. Copyright 2008 by the American Geophysical Union. 2008 English 00948276 10.1029/2008GL035263 Geophysical Research Letters 35 Section 2.2 GeoForschungsZentrum Potsdam, Telegrafenberg, D-14473 Potsdam, Germany; Department of Earth Sciences, University of Western Ontario, London, ON N6A 5B7, Canada 19 Anisotropy; Bearings (structural); Conformal mapping; Diagnostic radiography; Earthquakes; Electric network analysis; Feature extraction; Graph theory; Hydration; Image enhancement; Lithology; Medical imaging; Neural networks; Petroleum engineering; Petroleum prospecting; Sedimentology; Seismic prospecting; Seismology; Self organizing maps; Strength of materials; Tomography; Vectors, Attribute datums; Crosshole; Data vectors; Exploration strategies; High velocities; In-situ; Interlayering; Kohonen layers; Model vectors; Neural network analyses; Neural Network techniques; P velocities; P waves; Seismic signatures; Seismic tomographies; Strong anisotropies; Tomographic images; Watershed segmentation algorithms, Gas hydrates, algorithm; artificial neural network; crosshole seismic method; data set; gas hydrate; lithology; lithotype; P-wave; seismic anisotropy; seismic attenuation; seismic tomography; seismic velocity, Canada; Mackenzie Delta; North America; Northwest Territories https://www.scopus.com/inward/record.uri?eid=2-s2.0-57749189994&doi=10.1029%2f2008GL035263&partnerID=40&md5=a3bd3334ee3b432b293b53b6e5fb0def cited By 24 K. Bauer R.G. Pratt C. Haberland M. Weber article Cheng200855 Article 2008 Coal Geology & Exploration 36 77-80 6 J. Cai S. Gu X. Wu article Goto200845 Article 2008 10.1016/j.jvolgeores.2008.03.041 Journal of Volcanology and Geothermal Research 175 45 – 59 1-2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-50049084633&doi=10.1016%2fj.jvolgeores.2008.03.041&partnerID=40&md5=22dcd014d57a931402c62ceae8882d2f Cited by: 39 Yoshihiko Goto Setsuya Nakada Masaru Kurokawa Taketo Shimano Takeshi Sugimoto Sumio Sakuma Hideo Hoshizumi Mitsuhiro Yoshimoto Kozo Uto article oberhansli2008dry5 2008 GFZ Data Services Hedi Oberhänsli article Hayden2008327 The Chesapeake Bay impact structure is a ca. 35.4 Ma crater located on the eastern seaboard of North America. Deposition returned to normal shortly after impact, resulting in a unique record of both impact-related and subsequent passive margin sedimentation. We use backstripping to show that the impact strongly affected sedimentation for 7 m.y. through impact-derived crustal-scale tectonics, dominated by the effects of sediment compaction and the introduction and subsequent removal of a negative thermal anomaly instead of the expected positive thermal anomaly. After this, the area was dominated by passive margin thermal subsidence overprinted by periods of regional-scale vertical tectonic events, on the order of tens of meters. Loading due to prograding sediment bodies may have generated these events. © 2008 The Geological Society of America. 2008 English 00917613 10.1130/G24408A.1 Geology 36 327-330 Department of Geosciences, Western Michigan University, 1187 Rood Hall, 1903 W. Michigan Avenue, Kalamazoo, MI 49008, United States; United States Geological Survey, National Center, Reston, VA 20192, United States; Department of Geosciences, Rutgers The State University of New Jersey, Piscataway, NJ 08854, United States 4 Backstripping; Eocene; Impact processes; Passive margin, Sedimentology; Structural geology; Subsidence, Tectonics, deposition; Eocene; impact structure; passive margin; sedimentation; tectonic setting; temperature anomaly, Chesapeake Bay; North America; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-44449173977&doi=10.1130%2fG24408A.1&partnerID=40&md5=5f41e07e0c250ce5131c8a0d047afbd5 cited By 19 T. Hayden M. Kominz D.S. Powars L.E. Edwards K.G. Miller J.V. Browning A.A. Kulpecz article Collins2008221 We investigate the cause of terrace zone asymmetry in the Chicxulub impact crater using dynamic models of crater formation. Marine seismic data acquired across the crater show that the geometry of the crater's terrace zone, a series of sedimentary megablocks that slumped into the crater from the crater rim, varies significantly around the offshore half of the crater. The seismic data also reveal that, at the time of impact, both the water depth and sediment thickness varied with azimuth around the impact site. To test whether the observed heterogeneity in the pre-impact target might have affected terrace zone geometry we constructed two end-member models of upper-target structure at Chicxulub, based on the seismic data at different azimuths. One model, representing the northwest sector, had no water layer and a 3-km thick sediment layer; the other model, representing the northeast sector, had a 2-km water layer above a 4-km sediment layer. Numerical models of vertical impacts into these two targets produced final craters that differ substantially in terrace zone geometry, suggesting that the initial water depth and sediment thickness variations affected the structure of the terrace zone at Chicxulub. Moreover, the differences in terrace zone geometry between the two numerical models are consistent with the observed differences in the geometry of the terrace zone at different azimuths around the Chicxulub crater. We conclude that asymmetry in the pre-impact target rocks at Chicxulub is likely to be the primary cause of asymmetry in the terrace zone. © 2008 Elsevier B.V. All rights reserved. 2008 10.1016/j.epsl.2008.03.032 Earth and Planetary Science Letters 270 221-230 Earth Science and Engineering, Imperial College, London, United Kingdom; Earth Sciences, University of Cambridge, United Kingdom; Institute for Geophysics, Jackson School of Geosciences, TX, United States; Institute of Geophysics, UNAM, Mexico; Museum für Naturkunde, Humboldt-Universität Berlin, Germany 3-4 https://www.scopus.com/inward/record.uri?eid=2-s2.0-44649194411&doi=10.1016%2fj.epsl.2008.03.032&partnerID=40&md5=6f1127866871d2bb514b64e133deb029 cited By 96 G.S. Collins J. Morgan P. Barton G.L. Christeson S. Gulick J. Urrutia M. Warner K. Wünnemann article Bräuer2008 Comprehensive studies of CO2-rich fluids close to the swarm earthquake region Nový Kostel at the Czech-German border have been started 15 years ago and have in particular included two extended chemical and isotope monitoring studies lasting for several years each. The regional surface distribution patterns of the fluid signatures including the identification of the origin of fluid components are the focus of the detailed studies. Three degassing centers (Cheb basin, Mariánské Lázně, and Karlovy Vary) with high CO2 flux and the same level of δ13C values, but different levels of 3He/ 4He ratios, have been identified. The studies have located the CO2 source and have investigated seismically induced changes in fluid characteristics on the basis of unique weekly sampling campaigns at selected locations. A seismically triggered release of crustal helium was confirmed by both monitoring campaigns. Finally, indications for a presently active magmatic process beneath the Cheb basin have been found. In contrast to volcanically active regions, magma accumulation in the study area takes place at the crust-mantle boundary and is not yet accompanied by heat transfer to the surface. Likewise, reactive magma-derived components are absent in the degassing fluids. The area of investigation has the potential to be a natural laboratory for fundamental studies of active geodynamic processes. The results of our fluid monitoring, including the stunning observation of mantle-derived free fluids marked by 3He/4He ratios within the subcontinental mantle range, are supported by geophysical findings from seismic studies and geologic indications. Copyright 2008 by the American Geophysical Union. Article 2008 English 15252027 10.1029/2007GC001921 Geochemistry, Geophysics, Geosystems 9 4 https://www.scopus.com/inward/record.uri?eid=2-s2.0-57549101480&doi=10.1029%2f2007GC001921&partnerID=40&md5=52fc58ebe685ae0151238fad624f7c10 Cited by: 54 Karin Bräuer Horst Kämpf Samuel Niedermann Gerhard Strauch Jiří Tesař article Ayunov2008291 The Earth's surface topography disturbs the thermal field making measured superficial thermal gradients (heat flow) higher or lower than the deep value. Topographic disturbance can be removed from data by applying the respective correction. We estimated the effect of the rugged bottom of Lake Baikal on thermal gradients from the vicinity of boreholes BDP-93 and BDP-96 drilled in the lake sediments and deep borehole L-2 on the western shore of the South Baikal basin near Listvyanka Village. The corrections were computed using a Monte-Carlo simulation algorithm specially designed to quantify the effect of surface topography on the thermal field. The performance of the algorithm was checked by a test example. The corrections turned out to be vanishing in the area of underwater drilling but significant at L-2 where the thermal gradient in the upper 1 km of rocks was about 20% underestimated. The corrected heat flow in L-2 data increased from 50 to 60 mW/m2 and approached the values measured in the central South Baikal basin. © 2008. Article 2008 English 10687971 10.1016/j.rgg.2007.09.012 Russian Geology and Geophysics 49 291 – 296 4 Eurasia; Lake Baikal; Russian Federation; Calluna vulgaris; algorithm; computer simulation; correction; digital elevation model; estimation method; heat flow; lacustrine deposit; Monte Carlo analysis; performance assessment; temperature gradient; topographic effect https://www.scopus.com/inward/record.uri?eid=2-s2.0-41049109820&doi=10.1016%2fj.rgg.2007.09.012&partnerID=40&md5=839992e440561d2813bf47f6353f73a1 Cited by: 2 D.E. Ayunov A.D. Duchkov article Uddin20080325021 Continuing concern about the impacts of atmospheric carbon dioxide (CO 2) on the global climate system provides an impetus for the development of methods for long-term disposal of CO2 produced by industrial and other activities. Investigations of the CO2-hydrate properties indicate the feasibility of geologic sequestration CO2 as gas hydrate and the possibility of coincident CO2 sequestration/CH4 production from natural gas hydrate reservoirs. Numerical studies can provide an integrated understanding of the process mechanisms in predicting the potential and economic viability of CO2 gas sequestration, especially when utilizing realistic geological reservoir characteristics in the models. This study numerically investigates possible sequestration of CO2 as a stable gas hydrate in various reservoir geological formations. As such, this paper extends the applicability of a previously developed model to more realistic and relevant reservoir scenarios. A unified gas hydrate model coupled with a thermal reservoir simulator (CMG STARS) was applied to simulate CO2-hydrate formation in four reservoir geological formations. These reservoirs can be described as follows. The first reservoir (Reservoir I) is similar to tight gas reservoir with mean porosity 0.25 and mean absolute permeability 10 mD. The second reservoir (Reservoir II) is similar to a conventional sandstone reservoir with mean porosity 0.25 and mean permeability 20 mD. The third reservoir (Reservoir III) is similar to hydrate-free Mallik silt with mean porosity 0.30 and mean permeability 100 mD. The fourth reservoir (Reservoir IV) is similar to hydrate-free Mallik sand with mean porosity 0.35 and mean permeability 1000 mD. The Mallik gas hydrate bearing formation itself can be described as several layers of variable thickness with permeability variations from 1 mD to 1000 mD, and is addressed as a separate part of this study. This paper describes numerical methodology, model input data selection, and reservoir simulation results, including an enhancement to model the effects of ice formation and decay. The numerical investigation shows that the gas hydrate model effectively captures the spatial and temporal dynamics of CO2-hydrate formation in geological reservoirs by injection of CO2 gas. Practical limitations to CO2-hydrate formation by gas injection are identified and potential improvements to the process are suggested. Copyright © 2008 by ASME. 2008 English 01950738 10.1115/1.2956979 Journal of Energy Resources Technology, Transactions of the ASME 130 0325021-03250211 Alberta Research Council Inc., 250 Karl Clark Road, Edmonton, AB T6N 1E4, Canada; Computer Modeling Group Ltd., 3512-33 Street, NW, Calgary, AB T2L 2A6, Canada; Geological Survey of Canada, Terrain Sciences Division, Box 6000, 9860 West Saanich Road, Sidney, BC V8L 4B2, Canada 3 Atmospheric chemistry; Capillarity; Carbon dioxide; Data reduction; Gas hydrates; Gas industry; Gases; Hydration; Liquids; Numerical analysis; Petroleum reservoirs; Porosity; Solids; Water injection, CH4 hydrate; CO2 hydrate; CO2 sequestration; Geological reservoir; Hydrate decomposition; Hydrate formation; Numerical simulation, Petroleum reservoir engineering https://www.scopus.com/inward/record.uri?eid=2-s2.0-57249111695&doi=10.1115%2f1.2956979&partnerID=40&md5=03b71a72d6bed207a7862e8b1fe12c92 cited By 40 M. Uddin D. Coombe F. Wright article Walton2008351 Elongate, fine tubes, ∼1 μm wide and up to 200 μm long, extend from fractured surfaces, vesicle walls, and internal fractures into fragments of basalt glass in samples from the Hawaii Scientific Drilling Project #2 phase 1 (HSDP #21) core and the Hilina slope, Hawaii. Several features indicate that these tubes are microbial endolithic microborings: the tubes resemble many described microborings from oceanic basalt glass, their formation is postdepositional but restricted to certain but different ranges of time in the two sets of samples, and they are not uniformly distributed throughout glass fragments. Microtubules record several characteristic behaviors including boring into glass, mining, seeking olivine, and avoiding plagioclase. They also are highly associated with a particular form of glass-replacing smectite. Evidence of behavior should join morphological and geochemical criteria in indicating microbial alteration of basalt glass. In some samples, steeply conical tubes, ∼10-20 μm in diameter tapering to 1 μm and commonly filled with smectite, appear to be modifications or elaborations of the microtubules. These also curve toward olivine and are associated with replacement smectite. In HSDP #21 samples, microtubules initiated at margins of shards before palagonite replaced those margins and are preserved during palagonitization. In fact, microtubules appear to have provided routes that enhanced the efficiency of water's reaching of unaltered glass. In Hilina Slope samples, the microtubules appear to postdate palagonitization because they initiate at the boundary between palagonite and unaltered sideromelane. Preservation of microtubules during palagonitization in samples together with recognition of other associated characteristics representing behavior suggests that such features may be recognizable in more heavily altered ancient rocks. © 2008 The Author. 2008 English 14724677 10.1111/j.1472-4669.2008.00149.x Geobiology 6 351-364 Department of Geology, University of Kansas, 1475 Jayhawk Blvd, Lawrence, KS 66045, United States 4 silicate; silicon dioxide, basalt; endolithon; microorganism; olivine; palagonite; smectite; species occurrence, article; basalt; chemistry; microbiology; microscopy; microtubule; United States, Hawaii; Microscopy; Microtubules; Silicates; Soil Microbiology https://www.scopus.com/inward/record.uri?eid=2-s2.0-49249128065&doi=10.1111%2fj.1472-4669.2008.00149.x&partnerID=40&md5=dc9feeb56b04cba82fb33697eeb8455f cited By 40 A.W. Walton article Dahm2008529 Earthquake swarms are often assumed to be caused by magmatic or fluid intrusions, where the stress changes in the vicinity of the intrusion control the position, strength and rate of seismicity. Fracture mechanical models of natural intrusions or man-made hydrofractures pose constraints on orientation, magnitude, shape and growing rate of fractures and can be used to estimate stress changes in the vicinity of the intrusions. Although the idea of intrusion-induced seismicity is widely accepted, specific comparisons of seismicity patterns with fracture models of stress changes are rarely done. The goal of the study is to review patterns of intrusion-induced earthquake swarms in comparison to the observations of the swarm in NW Bohemia in 2000. We analyse and discuss the theoretical 3D shape of intrusions under mixed mode loading and apparent buoyancy. The aspect ratio and form of the intrusion is used to constrain parameters of the fluid, the surrounding rock and stress. We conclude that the 2000 NW Bohemia swarm could have been driven by a magmatic intrusion. The intrusion was, however, inclined to the maximal principal stress and caused shear displacement additional to opening. We estimate that the density diference between magma and rock was small. The feeding reservoir was possibly much larger than the area affected from earthquakes and may be a vertical dike beneath the swarm region. © Institute of Geophysics of the ASCR, v.v.i 2008. Article 2008 English 00393169 10.1007/s11200-008-0036-9 Studia Geophysica et Geodaetica 52 529 – 548 4 Bohemia; Central Europe; Czech Republic; Eurasia; Europe; earthquake swarm; fracture; igneous intrusion; magmatism; modeling; seismicity; stress https://www.scopus.com/inward/record.uri?eid=2-s2.0-57549101860&doi=10.1007%2fs11200-008-0036-9&partnerID=40&md5=ee59dd20ca9e59f58c7f71b12936e638 Cited by: 27 Torsten Dahm Tom Fischer S. Hainzl article Shervais2008 The trace of the Snake River-Yellowstone hot spot is the world's best example of a mantle plume that has been overridden by continental lithosphere. The "standard model" calls for the plume head to rise under northern Nevada and be forced northward to form basalts of the Columbia Plateau; subsequent movement of North America to the southwest over the plume tail created a hot spot trace on the surface. We present a new conceptual model for the origin of this feature that resolves inconsistencies in the current standard model and explains the recent documentation of a thermal anomaly in the mantle below Yellowstone today that plunges ∼ 65° WNW. Our model implies that the plume tail was forced beneath thinned cratonic lithosphere to the SE along with part of the plume head and has remained in this orientation for the last 12 Ma. We infer that almost all of the voicanism in SE Oregon and SW Idaho prior to 12 Ma results from overriding the southern extension of the plume head, not the plume tail, and that a distinct plume tail hot spot track was not established until formation of the Bruneau-Jarbidge eruptive center around 12 Ma. The plume tail track may also be controlled by a preexisting structural boundary in lithosphere that is thinner than adjacent lithosphere. This model demonstrates the potential importance of lithospheric topography on controlling the surface manifestation of plume volcanism and the complexity that may arise when lithospheric thickness is nonuniform. Copyright 2008 by the American Geophysical Union. 2008 English 02787407 10.1029/2007TC002181 Tectonics 27 Department of Geology, Utah State University, Logan, UT 84322-4505, United States; Department of Geological Sciences, San Diego State University, San Diego, CA 92182-1020, United States 5 basalt; continental lithosphere; craton; extensional tectonics; hot spot; mantle plume; structural control; topography; volcanic eruption; volcanism, Idaho; Nevada; North America; Oregon; Snake River; United States; Yellowstone River https://www.scopus.com/inward/record.uri?eid=2-s2.0-58149519348&doi=10.1029%2f2007TC002181&partnerID=40&md5=201d139369a6d75a0c81816e7317fa51 cited By 67 J.W. Shervais B.B. Hanan article Grad2008 The SUDETES 2003 seismic experiment investigated the lithospheric structure of the eastern part of the Variscan belt of central Europe. The key profile of this experiment (S01) was 630 km long and extended southwestward from the margin of the East European craton, across the Trans-European suture zone (TESZ) and Sudetes, and across the Bohemian Massif that contains the active Eger (Ohře) rift, which is an element of the European Cenozoic rift system. Good quality first arrivals and later phases of refracted/reflected P and S waves were interpreted using 2-D ray-tracing techniques. The derived seismic model shows large variations in the internal structure of the crust, while the depth to the Moho varies in the relatively narrow depth interval of 28-35 km. Except for the Polish basin on the northeast end of the profile, the sedimentary cover is thin. The crystalline upper and middle crust with velocities of 5.9-6.4 km S-1 is about 20 km thick, and the 7-10 km thick lower crust can be divided into three regions based on P wave velocities: a low-velocity region (6.5-6.6 km s-1 beneath Eger rift and Sudetes) that is bounded on the southwest and northeast by regions of significantly higher velocity (6.8-7.1 km s-1 beneath the Saxothuringian and Moldanubian in the southwest and Fore-Sudetic Monocline and Polish Basin in the northeast). High-velocity bodies (Vp > 6.5 km s-1) were delineated in the upper crust of the Eger rift region. The seismic structure along the S01 profile images a Variscan orogenic wedge resting on the down warped margin of the plate margin containing the TESZ. This situation implies the northerly directed subduction of the Rheic Ocean that existed between the southern margin of the Old Red Continent and the Armorican terranes presently accreted into the Variscan belt. Closure of this ocean produced the Rheic suture between low-velocity crust of the Variscan orogenic wedge and higher-velocity crust of the TESZ. Copyright 2008 by the American Geophysical Union. Article 2008 English 21699313 10.1029/2007JB005497 Journal of Geophysical Research: Solid Earth 113 Blackwell Publishing Ltd 10 Bohemian Massif; Central Europe; Eurasia; Europe; Cenozoic; craton; Hercynian orogeny; lithospheric structure; low velocity zone; Moho; orogenic belt; P-wave; ray tracing; S-wave; suture zone https://www.scopus.com/inward/record.uri?eid=2-s2.0-57649243094&doi=10.1029%2f2007JB005497&partnerID=40&md5=6aa4b6d4173ae855ded2143b9bc7959c Cited by: 78 Marek Grad Aleksander Guterch Stanisław Mazur G. Randy Keller Aleš Špičák Pavla Hrubcová Wolfram H. Geissler article Vasconcelos2008 Deconvolution interferometry successfully recovers the impulse response between two receivers without the need for an independent estimate of the source function. Here we extend the method of interferometry by deconvolution to multicomponent data in elastic media. As in the acoustic case, elastic deconvolution interferometry retrieves only causal scattered waves that propagate between two receivers as if one acts as a pseudosource of the point-force type. Interferometry by deconvolution in elastic media also generates artifacts because of a clamped-point boundary condition imposed by the deconvolution process. In seismic-while-drilling (SWD) practice, the goal is to determine the subsurface impulse response from drill-bit noise records. Most SWD technologies rely on pilot sensors and/or models to predict the drill-bit source function, whose imprint is then removed from the data. Interferometry by deconvolution is of most use to SWD applications in which pilot records are absent or provide unreliable estimates of bit excitation. With a numerical SWD subsalt example, we show that deconvolution interferometry provides an image of the subsurface that cannot be obtained by correlations without an estimate of the source autocorrelation. Finally, we test the use of deconvolution interferometry in processing SWD field data acquired at the San Andreas Fault Observatory at Depth (SAFOD). Because no pilot records were available for these data, deconvolution outperforms correlation in obtaining an interferometric image of the San Andreas fault zone at depth. © 2008 Society of Exploration Geophysicists. All rights reserved. 2008 English 00168033 10.1190/1.2904985 Geophysics 73 Society of Exploration Geophysicists S129-S141 Colorado School of Mines, Department of Geophysics, Center for Wave Phenomena, Egham, United Kingdom; ION Geophysical, GXT Imaging Solutions, Egham, United Kingdom; Colorado School of Mines, Department of Geophysics, Center for Wave Phenomena, Golden, CO, United States 3 Autocorrelation; Deconvolution; Drilling; Elastic waves; Imaging techniques; Impulse response; Interferometry; Seismic waves, Drill-bit seismic imaging; Elastic deconvolution interferometry; Multicomponent data; Seismic-while-drilling (SWD), Seismology, autocorrelation; boundary condition; deconvolution; drill bit; elastic wave; imaging method; interferometry; San Andreas Fault; seismic data; wave propagation; wave scattering https://www.scopus.com/inward/record.uri?eid=2-s2.0-43549085037&doi=10.1190%2f1.2904985&partnerID=40&md5=dd282820fd9e84472203dc767a76d183 cited By 118 I. Vasconcelos R. Snieder article Mayr2008 The borehole Yaxcopoil-1, drilled within the Chicxulub meteoritic impact structure (Mexico), was completely cored from 404 to 1511 in through postimpact Tertiary limestones underlain by impactites. The impactites comprise impact melt-rich, suevitic breccia followed by megablocks of Cretaceous limestones, calcarenites, dolomites, and anhydrites. Measurements of porosity, density, and thermal parameters on 450 samples (equidistant sampling, complete depth range) and of ultrasonic velocities and electric resistivity on 80 representative samples are used to investigate the physical properties of carbonate rocks and to study the influence of the impact. Experiments under elevated pressure, calculations using frequency-dependent Biot-Gassmann theory, and cross-checking with borehole logs, where available, show that ultrasonic laboratory and sonic in situ data correspond. Sonic and electric quasi-continuous logs are obtained from empirical correlations with thermal conductivity, density, and porosity and consideration of mineralogical composition and microstructure. These data give constraints on interpretation and geophysical modeling of, e.g., seismic and gravity data. In the Tertiary postimpact limestone section, the rock fabric (porosity) influences the physical properties. The upper boundary of the impactites is distinctly determined by the high inhomogeneity factor and anisotropy coefficient of thermal conductivity and by the temperature gradient from high-resolution borehole temperature measurements. All physical properties indicate that the upper part of the suevitic breccia can be distinguished from the lower suevite unit. In the Cretaceous megablocks, a high variability of all properties (particularly, thermal conductivity, density of solid material, and temperature gradient) due to the high variability in the mineral composition (calcite, dolomite, anhydrite) is observed. Copyright 2008 by the American Geophysical Union. 2008 10.1029/2007JB005420 Journal of Geophysical Research: Solid Earth 113 Angewandte Geophysik, Technische Universitaet Berlin, Sekr. ACK 2, Ackerstrasse 71-76, D-13355 Berlin, Germany; Lunar and Planetary Institute, 3600 Bay Area Boulevard, Houston, TX 77058, United States; Laboratory of Technical Physics, Russian State Geological Prospecting University, Miklukho-Maklaya street 23, 117997 Moscow, Russian Federation; Geophysikalisches Institut, Universitaet Karlsruhe, Hertzstrase 16, D-76187 Karlsruhe, Germany 7 https://www.scopus.com/inward/record.uri?eid=2-s2.0-51449121163&doi=10.1029%2f2007JB005420&partnerID=40&md5=ffd6edd61e56b93ea14c32828340ffa4 cited By 23 S.I. Mayr A. Wittmann H. Burkhardt Y. Popov R. Romushkevich I. Bayuk P. Heidinger H. Wilhelm article Urrutia-Fucugauchi2008801 The Chicxulub 200 km diameter crater located in the Yucatan platform of the Gulf of Mexico formed 65 Myr ago and has since been covered by Tertiary post-impact carbonates. The sediment cover and absence of significant volcanic and tectonic activity in the carbonate platform have protected the crater from erosion and deformation, making Chicxulub the only large multi-ring crater in which ejecta is well preserved. Ejecta deposits have been studied by drilling/coring in the southern crater sector and at outcrops in Belize, Quintana Roo and Campeche; little information is available from other sectors. Here, we report on the drilling/coring of a section of ∼34 m of carbonate breccias at 250 m depth in the Valladolid area (120 km away from crater center), which are interpreted as Chicxulub proximal ejecta deposits. The Valladolid breccias correlate with the carbonate breccias cored in the Peto and Tekax boreholes to the south and at similar radial distance. This constitutes the first report of breccias in the eastern sector close to the crater rim. Thickness of the Valladolid breccias is less than that at the other sites, which may indicate erosion of the ejecta deposits before reestablishment of carbonate deposition. The region east of the crater rim appears different from regions to the south and west, characterized by high density and scattered distribution of sinkholes. © 2008 Académie des sciences. 2008 10.1016/j.crte.2008.09.001 Comptes Rendus - Geoscience 340 801-810 Laboratorio de Paleomagnetismo y Paleoambientes, Programa Universitario de Perforaciones en Oceanos y Continentes, Instituto de Geofísica, DF, 04510 Mexico, Mexico; Departamento de Geología, Comisión Federal de Electricidad (CFE), GEIC-CFE, Mexico DF, Mexico; Residencia de Geohidrologia, Comisión Federal de Electricidad (CFE), Mérida, Yucatan, Mexico 12 https://www.scopus.com/inward/record.uri?eid=2-s2.0-57049165378&doi=10.1016%2fj.crte.2008.09.001&partnerID=40&md5=21d1de6b6e69ed07be60b405841751ae cited By 30 J. Urrutia-Fucugauchi J.M. Chavez-Aguirre L. Pérez-Cruz J.L. Rosa article 2008 Exploration Engineering (Rock &, Soil Drilling and Tunneling) 35 1-5 12 Q. Zhang Y. Zhu X Li J. Bi W. Wang article Noguchi200871 Groundmass textural and compositional analyses of the drilled dacite dykes of the Unzen Scientific Drilling Project (USDP-4) identify the feeder dyke of the 1990-1995 eruption and elucidate the crystallization process of dykes at depth. In the drilling depth range of 1582-1996 m ("conduit zone"), four dacite dykes were recognized. The groundmasses of all but one of these dykes have textures ranging from cryptocrystalline to microcrystalline aggregate of crystals &lt; 10 μm across forming an equigranular mosaic of plagioclase, alkali feldspar, quartz, and pyrite. The samples include a small number of coarser-grained plagioclase microlites (20 μm to 0.3 mm long). The compositions of groundmass consisting only of grains &lt; 10 μm plotted at the lower pressure (&lt; 50 MPa) ternary minimum in the Qz'-Ab'-Or' system suggests that the crystallization of plagioclase, alkali feldspar, and quartz took place nearly simultaneously. The compositions of coarser plagioclase microlites and groundmass, the plagioclase microlite textures, and the phenocryst assemblages show significant differences from historical lavas exposed in the summit area. This implies the possibility that most of the dacite dykes are not feeder dykes for the lavas at the summit and remained beneath the surface, perhaps because of high viscosity associated with high SiO2. One sample C14-1-1 collected 1977 m, has a texture, composition, and phenocryst assemblage nearly identical to that of the dome lava of the 1990-1995 eruption, differing only in the presence of hydrothermal alternation. At this time we cannot definitely conclude that C14-1-1 was the feeder dyke for the 1990-1995 eruption until we can elucidate the time scale and the conditions governing hydrothermal alternation. © 2008 Elsevier B.V. All rights reserved. 2008 English 03770273 10.1016/j.jvolgeores.2008.03.037 Journal of Volcanology and Geothermal Research 175 71-81 Department of Earth and Planetary Sciences, Graduate School of Sciences, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka, 812-8581, Japan; Volcano Research Center, Earthquake Research Institute, University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-0032, Japan; Technology and Research Center, Japan Oil, Gas and Metals National Corporation, 1-2-2, Hamada, Mihama-ku, Chiba, 261-0025, Japan 1-2 Crystallization; Crystallography; Drilling; Feeding; Feldspar; Metallic glass; Nanocrystalline alloys; Oxide minerals; Pyrites; Quartz; Silicon compounds; Textures, Alkali feldspar; annealing; Compositional analysis; conduit drilling; Crystallization processes; dacite dyke; Drilling depth; groundmass texture; hydrothermal alteration; Lower pressures; Microlite; Microlites; Unzen, Silicate minerals, crystallization; dacite; dike; drilling; hydrothermal alteration; lava dome; volcanic eruption, Asia; Eurasia; Far East; Japan; Kyushu; Nagasaki [Kyushu]; Unzen Volcano https://www.scopus.com/inward/record.uri?eid=2-s2.0-50049114104&doi=10.1016%2fj.jvolgeores.2008.03.037&partnerID=40&md5=b8a4a26bc098dbe5beef3221f26ada07 cited By 20 S. Noguchi A. Toramaru S. Nakada article Scheu2008110 Protracted dome-building eruptions may be profitably investigated using laboratory-based experiments. Density distribution studies on the pyroclastic flow deposits of Unzen 1990-1995 allow us to apply the results of experimental investigations on Unzen samples to the interpretation of the last eruption of Unzen. Here, primary laboratory experiments have focused on several aspects of the degassing (permeability) and the fragmentation behavior (threshold, speed, and efficiency). Those investigations have been flanked by analyses of flexural strength, fracture toughness, and seismic velocities, to provide new insights into eruption related processes. Here we present a review of these results and their application to the eruption dynamics of Unzen Volcano. We propose that efforts be made to incorporate routinely such comprehensive experimental analyses into the response to emerging volcanic crises in future. © 2008 Elsevier B.V. All rights reserved. 2008 English 03770273 10.1016/j.jvolgeores.2008.03.023 Journal of Volcanology and Geothermal Research 175 110-119 Earthquake Research Institute, University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, 113-0023 Tokyo, Japan; Department of Earth and Environmental Sciences, University of Munich, Theresienstr. 41 /III, 80333 Munich, Germany; Centro de Vulcanologia e Avaliação de Riscos Geológicos, Universidade dos Açores, 9501 - 801 Ponta Delgada, Açores, Portugal; Department of Earth Sciences, University of Bristol, Wills Memorial Building, Queens Road, Bristol, BS81RJ, United Kingdom 1-2 Degassing; Experiments; Fracture fixation; Landforms; Volcanic rocks; Volcanoes, block-and-ash flow; Density distributions; elastic wave velocities; Eruption dynamics; Experimental investigations; Flexural strength; fragmentation behavior; Laboratory experiments; permeability; porosity; Pyroclastic flow deposits; Seismic velocities; Unzen; volcanology, Fracture toughness, ash flow; degassing; fracture toughness; permeability; porosity; seismic velocity; volcanic eruption; volcanology, Asia; Eurasia; Far East; Japan; Kyushu; Nagasaki [Kyushu]; Unzen Volcano https://www.scopus.com/inward/record.uri?eid=2-s2.0-50049132862&doi=10.1016%2fj.jvolgeores.2008.03.023&partnerID=40&md5=f2cd89c93fc0f6dd8a406594c6c29ef5 cited By 36 B. Scheu U. Kueppers S. Mueller O. Spieler D.B. Dingwell article Phedorin200840 Assuming orbital modulation of Pleistocene climate cycles, we have generated a new time scale for the Asian geochemical limnic record in the BDP-96-2 Baikal and the KDP-01 Hovsgol cores and updated the chronologies for the global marine δ18O and Vostok ice-gas records. The time scales were obtained by orbital tuning with the assumption of arbitrary but time invariable amplitudes and phase lags of the orbital parameters and responses. The retuned chronologies highlighted the cycles of eccentricity (100 kyr), obliquity (41 kyr), and precession (23 and 19 kyr), but the combined 70- and 30-kyr cycles became less prominent in the continental (Baikal) record though persisted in the global data (Vostok δD). The residual 70- and 30-kyr harmonics more likely result from errors in the untuned chronology for the Baikal record but are rather due to nonlinearity in the climate response. We investigated the leads and lags of orbital climate signals with a special focus on the 100-kyr cycle. The phases of precession, obliquity, and eccentricity cycles, compared among the records, showed the lead of the continent. The Baikal geochemical signal at the 100-kyr band led the global glacial and greenhouse CH4 responses and was almost synchronous with the earliest responding polar temperature signal. The reported results characterize the continent as a system highly responsive to eccentricity variations but do not contradict alternative hypotheses for the origin of the 100-kyr cycle in the Earth's climate history. © 2007. Article 2008 English 10687971 10.1016/j.rgg.2007.12.005 Russian Geology and Geophysics 49 40 – 45 1 chronology; climate cycle; eccentricity; geochemistry; ice core; methane; paleoclimate; Pleistocene https://www.scopus.com/inward/record.uri?eid=2-s2.0-37349081302&doi=10.1016%2fj.rgg.2007.12.005&partnerID=40&md5=9ec919862c85caf265fdeb8ff93db8b4 Cited by: 2 M.A. Phedorin E.L. Goldberg book Ivanov2008163 To date around 180 impact structures have been identified on Earth. The diameters of these structures are from ∼10 to ∼200-250 km. Knowledge about terrestrial impact structures accumulated during many decades includes a large amount of geological and geophysical data. These data are very useful in formulating important constraints for impact model parameters reaching a double goal: (1) to fit parameters in the available mechanical models of planetary crust reaction to the impact event, and (2) to use numerical modeling to make an insight into the possible original structure of partially eroded terrestrial impact structures. This chapter presents results of numerical modeling for selected terrestrial impact craters (Puchezh-Karunki, Popigai, Vredefort, Sudbury, and Chicxulub) and compares model results with available geologic and geophysical data, obtained in the field study of aforementioned structures. © 2008 Springer. 2008 10.1007/978-1-4020-6452-4_5 Catastrophic Events Caused by Cosmic Objects 163-205 Institute for Dynamics of Geospheres, Russian Academy of Sciences, Moscow 119334, Russian Federation https://www.scopus.com/inward/record.uri?eid=2-s2.0-84891367573&doi=10.1007%2f978-1-4020-6452-4_5&partnerID=40&md5=157f0a56d954484fb698fec979e61926 cited By 6 B. Ivanov article NoAuthor2008 The US Geological Survey (USGS) estimated that 85.4 tcf of methane could be trapped in these cage-like lattices of ice about 2000 ft below the permafrost. According to USGS Director Mark Myers, a growing body of evidence indicates that concentrated gas-hydrate accumulations in conventional hydrocarbons reservoirs, such as those in northern Alaska, can be produced with existing technology, particularly depressurization. This technique lowers the pressure in the well, which causes the hydrates to become unstable and dissociate into water and gas that can be pumped to the surface. The Mallik 2002 Gas Hydrate Production Research Well Program, conducted in the Mackenzie Delta, Northwest Territories, Canada, represented the first modern, fully integrated field study and production testing of a gas-hydrate accumulation. It demonstrated that methane could be produced from gas hydrates by using pressure stimulation and that combining depressurisation with heating increased gas production. Numerous technical problems must still be overcome before this potential resource can be considered economically producible. One, for example, is the risk of releasing methane into the atmosphere; this gas is about 20 times more potent than CO2 as a greenhouse gas, which contributes to global warming. However, the effort would be worthwhile. The North Slope's hydrate reserves could provide enough gas to heat 100 m homes for up to a decade. The opportunity to develop them would also provide another justification for the proposed $26 billion, 1700 mi pipeline to carry conventionally produced natural gas from the North Slope to markets in the lower 48 states. 2008 English 0306395X Petroleum Economist 75 Petroleum Economist Ltd. 12 https://www.scopus.com/inward/record.uri?eid=2-s2.0-65249130682&partnerID=40&md5=4f3b24f2ee48a3f4d670093fd05e970e cited By 0 article huaichun2008establishment 2008 Earth Science Frontiers 15 Elsevier 159-169 4 Wu Huaichun Shihong Zhang Qinghua Huang article Lee2008 Relating pore-space gas hydrate saturation to sonic velocity data is important for remotely estimating gas hydrate concentration in sediment. In the present study, sonic velocities of gas hydrate-bearing sands are modeled using a three-phase Biot-type theory in which sand, gas hydrate, and pore fluid form threehomogeneous, interwoven frameworks. This theory is developed using well log compressional and shear wave velocity data from the Mallik 5L-38 permafrost gas hydrate research well in Canada and applied to well log data from hydrate-bearing sands in the Alaskan permafrost, Gulf of Mexico, and northern Cascadia margin. Velocity-based gas hydrate saturation estimates are in good agreement with Nuclear Magneto Resonance and resistivity log estimates over the complete range of observed gas hydrate saturations. Copyright 2008 by the American Geophysical Union. 2008 English 15252027 10.1029/2008GC002081 Geochemistry, Geophysics, Geosystems 9 U.S. Geological Survey, Box 25046, Denver Federal Center, Denver, CO 80225, United States; U.S. Geological Survey, 384 Woods Hole Road, Woods Hole, MA 02543, United States 7 https://www.scopus.com/inward/record.uri?eid=2-s2.0-66149169413&doi=10.1029%2f2008GC002081&partnerID=40&md5=c3af352ef1eeb01b7a09a772ef401771 cited By 142 M.W. Lee W.F. Waite article Mayr2008385 Internal surface, formation factor, Nuclear Magnetic Resonance (NMR)-T2 relaxation times and pore radius distributions were measured on representative core samples for the estimation of hydraulic permeability. Permeability is estimated using various versions of the classic Kozeny-Carman-equation (K-C) and a further development of K-C, the fractal PaRiS-model, taking into account the internal surface. In addition to grain and pore size distribution, directly connected to permeability, internal surface reflects the internal structure ("micro morphology"). Lithologies could be grouped with respect to differences in internal surface. Most melt rich impact breccia lithologies exhibit large internal surfaces, while Tertiary post-impact sediments and Cretaceous lithologies in displaced megablocks display smaller internal surfaces. Investigations with scanning electron microscopy confirm the correlation between internal surface and micro morphology. In addition to different versions of K-C, estimations by means of NMR, pore radius distributions and some gas permeability measurements serve for cross-checking and calibration. In general, the different estimations from the independent methods and the measurements are in satisfactory accordance. For Tertiary limestones and Suevites bulk with very high porosities (up to 35%) permeabilites between 10-14 and 10-16 m2 are found, whereas in lower Suevite, Cretaceous anhydrites and dolomites, bulk permeabilites are between 10-15 and 10-23m2. © Springer-Verlag 2007. 2008 10.1007/s00531-007-0227-6 International Journal of Earth Sciences 97 385-399 Department of Applied Geosciences, Technical University Berlin, Sekr. ACK 2, Ackerstraße 71-76, 13355 Berlin, Germany; Technical physics and rock physics, Russian State Geological Prospecting University, Miklukho-Maklaya street 23, 117997 Moscow, Russian Federation; Humboldt-Universität zu Berlin, Museum für Naturkunde, Mineralogie, Invalidenstrasse 43, 10115 Berlin, Germany 2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-41349086215&doi=10.1007%2fs00531-007-0227-6&partnerID=40&md5=8a122981f2c65859e22e734a326797b8 cited By 17 S.I. Mayr H. Burkhardt Yu. Popov A. Wittmann article Dai2008830 This article presents the results of applying a five-step process for using high-quality seismic data to locate marine gas hydrates. The process involved (1) reprocessing of seismic data for higher resolution, (2) detailed stratigraphic evaluation and interpretation to locate possible hydrate-bearing zones, (3) seismic attribute analysis to further delineate these zones, (4) seismic inversion to obtain appropriate elastic parameters of these zones in 3D, and (5) quantitative estimation of gas hydrate saturation from seismic data using inversion and rock physics principles. We used seismic data from Keathley Canyon 151 and Atwater Valley 14 in the northern Gulf of Mexico. Although careful analysis did indicate the presence of a bottom simulating reflector (BSR), our study mainly relied on a host of other seismic attributes (e.g., gas chimneys, seismically transparent zones, other features associated with the petroleum system) to characterize the occurrence of gas hydrates in these areas. We tested and verified a viable rock model for hydrate-bearing sediments using data from the Mallik (McKenzie Delta, Canada) and Blake Ridge (ODP Leg 164, southeast U.S. Atlantic margin) wells and modified it for application in the current area. We then used this model to estimate gas hydrate saturation in the host sediments of the northern Gulf of Mexico focus areas using estimates of P-wave and S-wave velocities from inversion of reflection seismic data. In this paper, we present the gas hydrate saturations predicted from the seismic processing methodology prior to 2005 drilling in the focus areas. In frontier areas where no well data are available and lithologic heterogeneities are poorly understood, implementing a seismic-based technique like the one described here to identify potential gas hydrates can provide valuable pre-drill information for site selection and for planning future characterization studies of gas hydrate-bearing sediments. 2008 English 02648172 10.1016/j.marpetgeo.2008.02.006 Marine and Petroleum Geology 25 830-844 Schlumberger, 10001 Richmond, Houston, TX 77042, United States 9 Bottom simulating reflector (BSR); Gas hydrate; Gulf of Mexico; Rock physics models; Seismic inversion, Bearings (structural); Gases; Geologic models; Hydration; Modal analysis; Offshore oil well production; Offshore oil wells; Offshore petroleum prospecting; Parameter estimation; Petroleum engineering; Petroleum prospecting; Reflection; Sedimentation; Sedimentology; Seismic response; Seismic waves; Seismology; Site selection; Stratigraphy; Three dimensional, Gas hydrates, deep water; estimation method; gas hydrate; hydrocarbon exploration; hydrocarbon reservoir; inverse analysis; P-wave; S-wave; seismic data; seismic method; seismic reflection; seismic velocity; three-dimensional modeling, Atlantic Ocean; Gulf of Mexico https://www.scopus.com/inward/record.uri?eid=2-s2.0-53349165624&doi=10.1016%2fj.marpetgeo.2008.02.006&partnerID=40&md5=11098a8fd485a3e2afff2ecf952819bc cited By 93 J. Dai F. Snyder D. Gillespie A. Koesoemadinata N. Dutta conference Williams2008 There is a growing interest in natural gas hydrate mainly due to the possibility that it may represent a large energy resource, potentially have an impact on global climate change and play a role in submarine slope failures. It is therefore of great importance to be able to identify the occurrence of in-situ gas hydrates and accurately assess their volume within the host sediments. The evaluation of gas hydrate volumes is dependent on a number of parameters, including the areal extent of the hydrate occurrence, reservoir thickness, porosity of reservoir and degree of hydrate saturation. Normally in hydrocarbon exploration of conventional oil and gas fields, the analysis of core samples, obtained while drilling, are used to evaluate this petrophysical data. However, because hydrate disassociates and loses gas as it is brought up to normal surface temperatures and pressure, it becomes problematical in obtaining meaningful porosity and saturation values from recovered cores. Therefore, downhole well logging techniques are used in order to obtain petrophysical data. These techniques have, in the main, been adapted from the standard hydrocarbon industry methods of determining porosity and saturations using resistivity and acoustic log data, together with the deterministic relationships such as the Archie (resistivity) and Wyllie (acoustic) time average equations. Deterministic formation evaluation methods follow a step-by-step approach to arrive at one solution for each depth step. In successive steps, the lithology, porosity, and saturations are determined. Thus the analytical parameters are fixed and the solutions unique. Another approach has been to use probabilistic statistical software such as the Mineral Solver module within the Interactive Petrophysics™ software package. Probabilistic evaluation, computes a solution from an assigned mineral model and all the available logs simultaneously, using statistical methods. This probabilistic method has been applied to log data acquired from the ODP/IODP (marine) and the Mallik (permafrost) exploration wells, successfully generating gas hydrate saturation estimates, with comparable results to Archie saturation estimates at high saturations. Further investigation is required to fully determine the potential of probabilistic methods for gas hydrate evaluation. © 2008 Society of Petrophysicists and Well-Log Analysts. All rights reserved. 2008 English 49th Annual Logging Symposium 2008 Society of Petrophysicists and Well-Log Analysts (SPWLA) Department of Geology, University of Leicester, Leicester, LE1 7RH, United Kingdom; British Geological Survey, Keyworth, Nottinghamshire, NG12 5GG, United Kingdom; RWE Dea AG, Hamburg, 22297, Germany Climate change; Energy resources; Gas hydrates; Gas industry; Gases; Hydration; Hydrocarbons; Lithology; Natural gas deposits; Petroleum prospecting; Petroleum reservoir evaluation; Porosity; Well logging, Conventional oil and gas; Gas hydrate bearing sediments; Gas hydrate saturations; Global climate changes; Hydrocarbon exploration; Porosity and saturation; Probabilistic evaluation; Submarine slope failures, Oil well logging https://www.scopus.com/inward/record.uri?eid=2-s2.0-85058839456&partnerID=40&md5=09a92eb097f2fc0212f5fd436b694427 cited By 0 F. Williams M. Lovell T. Brewer C. Buecker P. Jackson A. Camps article Vogel2008689 Measurements of Fourier transform infrared spectroscopy (FTIRS) in the mid-infrared (MIR) region were conducted on sedimentary records from Lake El'gygytgyn, NE Siberia, and Lake Ohrid, Albania/Macedonia. Calibration models relating FTIR spectral information to biogeochemical property concentrations were established using partial least squares regression (PLSR). They showed good statistical performance for total organic carbon (TOC), total nitrogen (TN), and biogenic silica (opal) in the sediment record from Lake El'gygytgyn, and for TOC, total inorganic carbon (TIC), TN, and opal in sediments from Lake Ohrid. In both cases, the calibration models were successfully applied for down-core analysis. The results, in combination with the small amount of sample material needed, negligible sample pre-treatments, and low costs of analysis, demonstrate that FTIRS is a promising, cost-effective tool that allows high-resolution paleolimnological studies. © 2008 Springer Science+Business Media B.V. Article 2008 English 09212728 10.1007/s10933-008-9193-7 Journal of Paleolimnology 40 689 – 702 2 Chukchi; Elgygytgyn Lake; Eurasia; Europe; Lake Ohrid; Russian Federation; Southern Europe; biogenic deposit; biogeochemistry; cost-benefit analysis; FTIR spectroscopy; paleolimnology; quantitative analysis; sediment core https://www.scopus.com/inward/record.uri?eid=2-s2.0-46649121481&doi=10.1007%2fs10933-008-9193-7&partnerID=40&md5=0276302f1f01a23ab50212e2b90b4efe Cited by: 69; All Open Access, Green Open Access Hendrik Vogel Peter Rosén Bernd Wagner Martin Melles Per Persson article Vogel2008689 Measurements of Fourier transform infrared spectroscopy (FTIRS) in the mid-infrared (MIR) region were conducted on sedimentary records from Lake El'gygytgyn, NE Siberia, and Lake Ohrid, Albania/Macedonia. Calibration models relating FTIR spectral information to biogeochemical property concentrations were established using partial least squares regression (PLSR). They showed good statistical performance for total organic carbon (TOC), total nitrogen (TN), and biogenic silica (opal) in the sediment record from Lake El'gygytgyn, and for TOC, total inorganic carbon (TIC), TN, and opal in sediments from Lake Ohrid. In both cases, the calibration models were successfully applied for down-core analysis. The results, in combination with the small amount of sample material needed, negligible sample pre-treatments, and low costs of analysis, demonstrate that FTIRS is a promising, cost-effective tool that allows high-resolution paleolimnological studies. © 2008 Springer Science+Business Media B.V. 2008 English 09212728 10.1007/s10933-008-9193-7 Journal of Paleolimnology 40 689-702 Institute of Geology and Mineralogy, University of Cologne, Zülpicher Str. 49a, 50674 Cologne, Germany; Climate Impacts Research Centre (CIRC), Umeå University, Abisko 98107, Sweden; Department of Chemistry, Umeå University, Umea 90187, Sweden 2 biogenic deposit; biogeochemistry; cost-benefit analysis; FTIR spectroscopy; paleolimnology; quantitative analysis; sediment core, Chukchi; Elgygytgyn Lake; Eurasia; Europe; Lake Ohrid; Russian Federation; Southern Europe https://www.scopus.com/inward/record.uri?eid=2-s2.0-46649121481&doi=10.1007%2fs10933-008-9193-7&partnerID=40&md5=0276302f1f01a23ab50212e2b90b4efe cited By 69 H. Vogel P. Rosen B. Wagner M. Melles P. Persson article Song2007 2007 English 10170839 10.3319/TAO.2007.18.2.I(TCDP) Terrestrial, Atmospheric and Oceanic Sciences 18 I-VI Department of Geosciences, National Taiwan University, Taipei, Taiwan; Department of Earth Sciences, Institute of Geophysics, National Central University, Chung-Li, Taiwan 2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-34547556308&doi=10.3319%2fTAO.2007.18.2.I%28TCDP%29&partnerID=40&md5=27c03ab0708b35fe2aacffbff2872ee8 cited By 12 S.-R. Song C.-Y. Wang J.-H. Hung K.-F. Ma article Anselmetti2007915 We used seismic and sediment core data to quantify soil erosion rates for the past ∼6000 yr in the closed catchment of Lake Salpetén, in the tropical lowlands of northern Guatemala. The region was affected by ancient Maya land use from before ca. 1000 B.C. to A.D. 900. This period of human impact coincided with deposition in the lake of a detrital unit (Maya Clay) as much as 7 m thick that contrasts sharply with the relatively organic-rich gyttja deposited both before and after Maya occupation of the watershed. The greatest soil loss, with mean sustained values of ∼1000 t/kM2 yr-1, occurred in the Middle and Late Preclassic Periods (700 B.C. to A.D. 250), associated with relatively low Maya population densities. Soil erosion slowed during the period of maximum population density in the Late Classic Period (A.D. 550-830), indicating a decoupling between human population density and soil erosion rate. The most rapid soil loss occurred early during initial land clearance, suggesting that even low numbers of people can have profound impacts on lowland tropical karst landscapes. © 2007 The Geological Society of America. 2007 English 00917613 10.1130/G23834A.1 Geology 35 915-918 Geological Institute, Swiss Federal Institute of Technology, ETH, 8092 Zurich, Switzerland; Department of Geological Sciences, University of Florida, Gainesville, FL 32611, United States; Section of Earth Sciences, University of Geneva, 1205 Geneva, Switzerland; Department of Geology and Planetary Sciences, University of Pittsburgh, Pittsburgh, PA 15260, United States; Swiss Federal Institute of Aquatic Science and Technology (Eawag), Ueberlandstr. 133, CH-8600 Duebendorf, Switzerland 10 Lake sediments; Seismic stratigraphy; Soil erosion rate, Erosion; Lakes; Sediments; Seismology; Stratigraphy, Structural geology, anthropogenic effect; Classic period; core analysis; deforestation; deposition; erosion rate; gyttja; lacustrine deposit; land use; seismic data; seismic stratigraphy; soil erosion, Central America; Guatemala [Central America] https://www.scopus.com/inward/record.uri?eid=2-s2.0-35448988374&doi=10.1130%2fG23834A.1&partnerID=40&md5=ed23aaf6f8862ef9839e0b70c30e503f cited By 153 F.S. Anselmetti D.A. Hodell D. Ariztequi M. Brenner M.F. Rosenmeier article Lin2007379 In order to understand the feature of rock stress change at different depths above, within, and beneath the Chelungpu fault after the Chi-Chi earthquake, we employed a core-based stress measurement method, anelastic strain recovery (ASR) technique to determine both the orientations and magnitudes of present three-dimensional principal rock stresses using drill core samples retrieved from Taiwan Chelungpu-fault Drilling Project (TCDP) main Hole-A. The core samples used were taken from three depths; and their lithology were sandstone at depths of 592 and 1755 m and siltstone at 1112 m. The anelastic strains of the specimens in nine directions, including six independent directions, were measured after its in-situ stress was released. Acquired anelastic strains were of high quality and reached several hundred microstrains, which is sufficiently high for the accuracy of the measurement system used. Thus, the strain data could be used for three-dimensional analysis resulting in the determination of orientations and the estimation of magnitudes of the principal in-situ stresses. Preliminary stress measurement results showed that the orientations of principal stresses changed between the shallower depth above the fault and the deeper depth beneath it, that is, the present stress distribution in the TCDP hole might be influenced by the Chelungpu fault rupture. At the same time, anelastic strain recovery measurement is well suited for the task of directly determining the orientations of principal in-situ stresses and to estimate the magnitude of stresses at large/great depth. 2007 English 10170839 10.3319/TAO.2007.18.2.379(TCDP) Terrestrial, Atmospheric and Oceanic Sciences 18 379-393 Kochi Institute for Core Sample Research, Japan Agency for Marine-Earth Science and Technology, Kochi, Japan; Center for Deep Earth Exploration, Japan Agency for Marine-Earth Science and Technology, Yokohama, Japan; Department of Earth and Space Science, Graduate School of Science, Osaka University, Toyonaka, Japan; Department of Earth Sciences, Institute of Geophysics, National Central University, Chung-Li, Taiwan; Department of Geosciences, National Taiwan University, Taipei, Taiwan 2 anelasticity; borehole; Chi-Chi earthquake 1999; core analysis; drilling; fault zone; in situ measurement; siltstone; strain; stress measurement; three-dimensional modeling https://www.scopus.com/inward/record.uri?eid=2-s2.0-34547587461&doi=10.3319%2fTAO.2007.18.2.379%28TCDP%29&partnerID=40&md5=e69ec227e125175a3a91bc311b317cd1 cited By 37 W. Lin E.-C. Yeh H. Ito T. Hirono W. Soh C.-Y. Wang K.-F. Ma J.-H. Hung S.-R. Song article Koeberl2007481 Editorial 2007 English 10869379 10.1111/j.1945-5100.2007.tb01056.x Meteoritics and Planetary Science 42 University of Arkansas 481 – 482 4-5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-34250687520&doi=10.1111%2fj.1945-5100.2007.tb01056.x&partnerID=40&md5=f52a2ddfb24452838c4edac67edca218 Cited by: 1; All Open Access, Bronze Open Access Christian Koeberl Bernd Milkereit Wolf Uwe Reimold article Cheng200855 Article 2007 China Basic Science 6 22-26 C. Wang article Fridleifsson200726 2007 English 18168957 10.2204/iodp.sd.4.04.2007 Scientific Drilling 26-29 ISOR, Iceland GeoSurvey, Grensasvegur 9, IS-108 Reykjavik, Iceland; Department of Earth Sciences, University of California, Riverside, CA 92521, United States 4 https://www.scopus.com/inward/record.uri?eid=2-s2.0-78651524241&doi=10.2204%2fiodp.sd.4.04.2007&partnerID=40&md5=c35bad59946474038f8c2ff5465e47ec cited By 4 G.Ó. Fridleifsson W.A. Elders article dAlessio2007 A suite of new techniques in thermochronometry allow analysis of the thermal history of a sample over a broad range of temperature sensitivities. New analysis tools must be developed that fully and formally integrate these techniques, allowing a single geologic interpretation of the rate and timing of exhumation and burial events consistent with all data. We integrate a thermal model of burial and exhumation, (U-Th)/He age modeling, and fission track age and length modeling. We then use a genetic algorithm to efficiently explore possible time-exhumation histories of a vertical sample profile (such as a borehole), simultaneously solving for exhumation and burial rates as well as changes in background heat flow. We formally combine all data in a rigorous statistical fashion. By parameterizing the model in terms of exhumation rather than time-temperature paths (as traditionally done in fission track modeling), we can ensure that exhumation histories result in a sedimentary basin whose thickness is consistent with the observed basin, a physically based constraint that eliminates otherwise acceptable thermal histories. We apply the technique to heat flow and thermochronometry data from the 2.1 -km-deep San Andreas Fault Observatory at Depth pilot hole near the San Andreas fault, California. We find that the site experienced <1 km of exhumation or burial since the onset of San Andreas fault activity ∼30 Ma. 2007 English 21699313 10.1029/2006JB004725 Journal of Geophysical Research: Solid Earth 112 Blackwell Publishing Ltd U.S. Geological Survey, 345 Middlefield Road, Menlo Park, CA 94025, United States; Earthquake Research Institute, University of Tokyo, Tokyo, Japan 8 burial (geology); exhumation; genetic algorithm; heat flow; numerical model; parameterization; thermochronology, California; North America; San Andreas; United States, Calluna vulgaris https://www.scopus.com/inward/record.uri?eid=2-s2.0-35348873786&doi=10.1029%2f2006JB004725&partnerID=40&md5=0ac9b107aef43b7f6e76ab5db1a1074e cited By 8 M.A. d'Alessio C.F. Williams article Solum200764 2007 English 18168957 10.2204/iodp.sd.s01.34.2007 Scientific Drilling 64-67 U.S. Geological Survey, Earthquake Hazards Team, 345 Middlefield Road, Mail Stop 977, Menlo Park, Calif., United States; Department of Geosciences, Stony Brook University, 255 Earth and Space Sciences Building (ESS), Stony Brook N.Y. 11794-2100, United States; Department of Geology, Utah State University, Logan, Utah 84322-4505, United States; Department of Earth and Atmospheric Sciences, Saint Louis University, Verhaegen Hall, 3634 Lindell Boulevard, Suite 117, St. Louis, Mo. 63103, United States; Department of Geology and Geophysics, Texas A and M University, College Station, Texas 77843-3115, United States; Department of Geology and Geophysics, M.T. Halbouty Building, Texas A and M University, College Station, Texas 77843-3115, United States; Department of Geological Sciences, University of Michigan, 4534B C.C. Little Building, 1100 North University Avenue, Ann Arbor, Mich. 48109-1005, United States; Department of Geological Sciences, University of Michigan, 2534 C.C. Little Building, 1100 North University Avenue, Ann Arbor, Mich. 48109-1005, United States; Department of Geology, Utah State University, Logan, Utah 84322-4505, United States 1 SUPPL. 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-72049094408&doi=10.2204%2fiodp.sd.s01.34.2007&partnerID=40&md5=229ee14ef0408006486dcec0541fe7f7 cited By 11 J.G. Solum S. Hickman D.A. Lockner S. Tembe J.P. Evans S.D. Draper D.C. Barton D.L. Kirschner J.S. Chester F.M. Chester B.A. Pluijm A.M. Schleicher D.E. Moore C. Morrow K. Bradbury W.M. Calvin T.-F. Wong article Fritz2007410 A 136-m-long drill core of sediments was recovered from tropical high-altitude Lake Titicaca, Bolivia-Peru, enabling a reconstruction of past climate that spans four cycles of regional glacial advance and retreat and that is estimated to extend continuously over the last 370,000 yr. Within the errors of the age model, the periods of regional glacial advance and retreat are concordant respectively with global glacial and interglacial stages. Periods of ice advance in the southern tropical Andes generally were periods of positive water balance, as evidenced by deeper and fresher conditions in Lake Titicaca. Conversely, reduced glaciation occurred during periods of negative water balance and shallow closed-basin conditions in the lake. The apparent coincidence of positive water balance of Lake Titicaca and glacial growth in the adjacent Andes with Northern Hemisphere ice sheet expansion implies that regional water balance and glacial mass balance are strongly influenced by global-scale temperature changes, as well as by precessional forcing of the South American summer monsoon. © 2007 University of Washington. Article 2007 10.1016/j.yqres.2007.07.008 Quaternary Research 68 410 – 420 3 Lake Titicaca; South America; Bacillariophyta; glaciation; ice sheet; interglacial; paleoclimate; paleohydrology; Quaternary; reconstruction; sediment core; tropical region; water budget https://www.scopus.com/inward/record.uri?eid=2-s2.0-35348819351&doi=10.1016%2fj.yqres.2007.07.008&partnerID=40&md5=d0d468b6f8780f70f98b2a5ce350bf42 Cited by: 100; All Open Access, Green Open Access Sherilyn C. Fritz Paul A. Baker Geoffrey O. Seltzer Ashley Ballantyne Pedro Tapia Hai Cheng R. Lawrence Edwards article Wittmann20071151 Formation conditions of suevite-like impactites from an ∼100 m thick drill core sequence through the Cretaceous-Tertiary Chicxulub crater were reconstructed from empirical data obtained by petrologic and image analytical methods. The temporal evolution of the cratering process from the initial stage of excavation to the collapse of the ejecta plume is evidenced by the petrographic characteristics and modal composition of the suevitic rocks, including the size distribution and shape parameters of melt particles. Emplacement of the lowermost suevitic deposits likely started in the first minute after the impact by the passing ejecta curtain that interacted with the expanding ejecta plume. These ejecta deposits were capped by a tongue of coherent impact melt that was transported outward from the crater center during the collapse of the central uplift ∼5 min after impact. On top of this brecciated impact melt rock, the collapsing ejecta plume deposited air-fall suevites. The basal air-fall unit, Middle Suevite, may have been deposited due to a density current-like clumping of hot debris. With progressive cooling, regions of the ejecta plume were entrained in its collapse that produced vapor condensates, accretionary rims, and different oxygen fugacities. After cooling progressed, atmospheric conditions began to reestablish over the crater and turbulence decreased, supposedly after the first 10 min of initial ejecta plume collapse. This led to a winnowing out of fine matrix material and distinct sorting. However, due to aquatic reworking, only material that was deposited until ∼1 h after cessation of turbulent atmospheric conditions was retained. © 2007 Geological Society of America. 2007 10.1130/B26116.1 Bulletin of the Geological Society of America 119 1151-1167 Museum für Naturkunde, Mineralogie, Invalidenstrasse 43, 10115 Berlin, Germany; 250 Little St., Athens, GA 30605, United States 9-10 https://www.scopus.com/inward/record.uri?eid=2-s2.0-34648846171&doi=10.1130%2fB26116.1&partnerID=40&md5=990afa31bfc215efb0d28145210bb5e8 cited By 27 A. Wittmann T. Kenkmann L. Hecht D. Stöffler article Dreger2007 We investigate the rupture process of a sequence of repeating Mw 2.1 earthquakes on the San Andreas Fault in Parkfield spanning the occurrence of the September 28, 2004 mainshock by inverting seismic moment rate functions obtained from empirical Green's function deconvolution. The results show that these events have extremely concentrated slip patches with radii on the order of 10-20 m, with peak slip between 8.4 and 11.4 cm. The rupture speed and rise time are consistent with values of larger earthquakes. The spatial distribution of stress drop for the events shows low average values 2.5-5.6 MPa and very large peak values of 66.7-93.9 MPa. The results show that strong asperities can exist at small scales on an otherwise weak fault, and helps reconcile differences between traditional spectra-based and tectonic loading methods for determining the stress drop of small repeating earthquakes. Copyright 2007 by the American Geophysical Union. 2007 English 00948276 10.1029/2007GL031353 Geophysical Research Letters 34 Berkeley Seismological Laboratory, University of California, Berkeley, CA 94720, United States 23 Mathematical models; Seismic response; Seismographs; Seismology; Tectonics, Rupture process; Rupture speed; Seismic moment rate; Tectonic loading, Earthquakes, deconvolution; earthquake magnitude; earthquake rupture; Green function; San Andreas Fault; seismic moment; spatial distribution https://www.scopus.com/inward/record.uri?eid=2-s2.0-39049102445&doi=10.1029%2f2007GL031353&partnerID=40&md5=e740b15fa23706c9209baaeff19bc38d cited By 83 D. Dreger R.M. Nadeau A. Chung article Danour2007541 Gravity and magnetic measurements were carried out at the Bosumtwi crater to determine the geophysical signature of the crater. Land gravity data was acquired at 163 locations around the structure and on the shore of the lake. The separation between the gravity stations was 500 m for radial profiles, but 700-1000 m along roads and footpaths that ran parallel to the lake's shore. Additionally, a marine gravity survey was carried out along 14 north-south and 15 east-west profiles on the lake. Magnetic data was also acquired along 14 north-south profiles on the lake. In all marine surveys, the line spacing was 800 m, and navigation was provided by a Garmin 235 Echo Sounder/GPS. The gravity signature of the crater is characterized by a negative Bouguer anomaly with an amplitude of about -18 mgal. Using the seismic results as constraints, the gravity model obtained indicates the central uplift at a depth of 250 m. The negative anomaly is the contribution of the gravity deficiencies due to fractured and brecciated rocks in the rim area and below the crater floor, the impact breccias within the crater, and the sedimentary and water infilling of the lake. Magnetic modeling yielded a model for the causative body, which is located north of the central uplift: the model has a magnetic susceptibility of 0.03 S.I. and extends from a depth of 250 to 610 m. The causative bodies have been interpreted as impactites. © The Meteoritical Society, 2007. Printed in USA. Article 2007 English 10869379 10.1111/j.1945-5100.2007.tb01059.x Meteoritics and Planetary Science 42 University of Arkansas 541 – 547 4-5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-34250631970&doi=10.1111%2fj.1945-5100.2007.tb01059.x&partnerID=40&md5=d51ea88805da42203e915923e76458b6 Cited by: 3 S.K. Danour A. Menyeh book Reches2007235 Drilling into active faults has become a major scientific endeavor during the last decade and it appears as a most promising approach to resolve long-standing questions in earthquake and faulting processes. The first boreholes were drilled into the Nojima Fault following the 1995 Kobe earthquake. Since then, drilling into active faults has begun or been planned in a wide range of tectonic settings, such as a strike-slip plate boundary (San Andreas Fault, California), a thrust zone in an active orogenic belt (Chelungpu Fault, Taiwan), a normal fault in an active rift zone (Aigion Fault, Greece), a reactivated Archean fault (Pretorius Fault, South Africa), and a major subduction thrust (Nankai Thrust, Japan). These projects have already revealed many details on in-situ stresses, fault-zone structure, fault-rock composition, mechanical properties, heat flow, and near-field seismicity. Furthermore, most of these projects will continue to serve as observatories for monitoring fault deformation, fluid pressure and near-field earthquake source processes for a decade or two. Future drilling projects will focus on near-field observations and long-term monitoring of time-dependent processes and in-situ experimentation in active fault zones. Collaboration with industry and government will address practical issues pertaining to petroleum and geothermal energy, radioactive waste disposal, and urban seismic hazards. The outcome of these international efforts in drilling active faults will revolutionize our understanding of the processes controlling faulting and earthquakes and lead to a stronger scientific basis for earthquake hazard mitigation. © 2007 Springer-Verlag Berlin Heidelberg. 2007 English 9783540687771 10.1007/978-3-540-68778-8_6 Continental Scientific Drilling: A Decade of Progress, and Challenges for the Future Springer Berlin Heidelberg 235-258 School of Geology and Geophysics, University of Oklahoma, Norman, OK 73019, United States; Center for Deep Earth Exploration, Japan Agency for Marine-Earth Science and Technology, Yokohama, Kanagawa 236-0001, Japan https://www.scopus.com/inward/record.uri?eid=2-s2.0-58749095781&doi=10.1007%2f978-3-540-68778-8_6&partnerID=40&md5=2970d8913c96830d31b3214ee317af9a cited By 13 Z. Reches H. Ito article Tsikalas20072013 Post-impact crater morphology and structure modifications due to sediment loading are analyzed in detail and exemplified in five well-preserved impact craters: Mjølnir, Chesapeake Bay, Chicxulub, Montagnais, and Bosumtwi. The analysis demonstrates that the geometry and the structural and stratigraphic relations of post-impact strata provide information about the amplitude, the spatial distribution, and the mode of post-impact deformation. Reconstruction of the original morphology and structure for the Mjølnir, Chicxulub, and Bosumtwi craters demonstrates the long-term subsidence and differential compaction that takes place between the crater and the outside platform region, and laterally within the crater structure. At Mjølnir, the central high developed as a prominent feature during post-impact burial, the height of the peak ring was enhanced, and the cumulative throw on the rim faults was increased. The original Chicxulub crater exhibited considerably less prominent peak-ring and inner-ring/crater-rim features than the present crater. The original relief of the peak ring was on the order of 420-570 m (currently 535-575 m); the relief on the inner ring/ crater rim was 300-450 m (currently ∼700 m). The original Bosumtwi crater exhibited a central uplift/high whose structural relief increased duringburial (current height 101-110 m, in contrast to the original height of 85-110 m), whereas the surrounding western part of the annular trough was subdued more that the eastern part, exhibiting original depths of 43-68 m (currently 46 m) and 49-55 m (currently 50 m), respectively. Furthermore, a quantitative model for the porosity change caused by the Chesapeake Bay impact was developed utilizing the modeled density distribution. The model shows that, compared with the surrounding platform, the porosity increased immediately after impact up to 8.5% in the collapsed and brecciated crater center (currently +6% due to post-impact compaction). In contrast, porosity decreased by 2-3% (currently -3 to -4.5% due to post-impact compaction) in the peak-ring region. The lateral variations in porosity at Chesapeake Bay crater are compatible with similar porosity variations at Mjølnir crater, and are considered to be responsible for the moderate Chesapeake Bay gravity signature (annular low of -8 mGal instead of -15 mGal). The analysis shows that the reconstructions and the long-term alterations due to post-impact burial are closely related to the impact-disturbed target-rock volume and a brecciated region of laterally varying thickness and depth-varying physical properties. The study further shows that several crater morphological and structural parameters are prone to post-impact burial modification and are either exaggerated or subdued during post-impact burial. Preliminary correction factors are established based on the integrated reconstruction and post-impact deformation analysis. The crater morphological and structural parameters, corrected from post-impact loading and modification effects, can be used to better constrain cratering scaling law estimates and impact-related consequences. © The Meteoritical Society, 2007. 2007 10.1111/j.1945-5100.2007.tb00557.x Meteoritics and Planetary Science 42 2013-2029 Department of Geosciences, University of Oslo, P.O. Box 1047 Blindern, NO-0316 Oslo, Norway; ENI Norge AS, P.O. Box 101 Forus, NO-4064 Stavanger, Norway 11 https://www.scopus.com/inward/record.uri?eid=2-s2.0-41549143722&doi=10.1111%2fj.1945-5100.2007.tb00557.x&partnerID=40&md5=c78c1e98890dfb566c012c2b14a32776 cited By 11 F. Tsikalas J.I. Faleide book Reches2007235 Drilling into active faults has become a major scientific endeavor during the last decade and it appears as a most promising approach to resolve long-standing questions in earthquake and faulting processes. The first boreholes were drilled into the Nojima Fault following the 1995 Kobe earthquake. Since then, drilling into active faults has begun or been planned in a wide range of tectonic settings, such as a strike-slip plate boundary (San Andreas Fault, California), a thrust zone in an active orogenic belt (Chelungpu Fault, Taiwan), a normal fault in an active rift zone (Aigion Fault, Greece), a reactivated Archean fault (Pretorius Fault, South Africa), and a major subduction thrust (Nankai Thrust, Japan). These projects have already revealed many details on in-situ stresses, fault-zone structure, fault-rock composition, mechanical properties, heat flow, and near-field seismicity. Furthermore, most of these projects will continue to serve as observatories for monitoring fault deformation, fluid pressure and near-field earthquake source processes for a decade or two. Future drilling projects will focus on near-field observations and long-term monitoring of time-dependent processes and in-situ experimentation in active fault zones. Collaboration with industry and government will address practical issues pertaining to petroleum and geothermal energy, radioactive waste disposal, and urban seismic hazards. The outcome of these international efforts in drilling active faults will revolutionize our understanding of the processes controlling faulting and earthquakes and lead to a stronger scientific basis for earthquake hazard mitigation. © 2007 Springer-Verlag Berlin Heidelberg. 2007 English 9783540687771 10.1007/978-3-540-68778-8_6 Continental Scientific Drilling: A Decade of Progress, and Challenges for the Future Springer Berlin Heidelberg 235-258 School of Geology and Geophysics, University of Oklahoma, Norman, OK 73019, United States; Center for Deep Earth Exploration, Japan Agency for Marine-Earth Science and Technology, Yokohama, Kanagawa 236-0001, Japan https://www.scopus.com/inward/record.uri?eid=2-s2.0-58749095781&doi=10.1007%2f978-3-540-68778-8_6&partnerID=40&md5=2970d8913c96830d31b3214ee317af9a cited By 13 Z. Reches H. Ito article Xu2007541 Knowledge of the variability of precipitation at Lake Qinghai and its relation to the Asian summer monsoons is helpful in constraining global climatic dynamics. Based on the high-resolution precipitation indicators of δ13C of the organic matter (δ13Corg), C/N atomic ratio, and the detrended total organic carbon content (TOCdetrended), we found that the trend of precipitation at Lake Qinghai is inversely correlated to that of the Indian Summer Monsoon (ISM) inferred from layer thickness of a stalagmite (S3) in southern Oman on decadal/interdecadal scales. The Chinese Drought/Flood (D/F) indices, which can indicate the dryness/wetness over large geographic areas, are also used to indicate the intensity of the monsoon rainfall. The D/F index of Xining near Lake Qinghai is synchronous with those of the regions in northern China where the East Asian Summer Monsoon (EASM) dominates; while it is anti-phase with those of southwestern China where ISM prevails. These materials suggest that, during the past 500 years, the source of moisture to Lake Qinghai on decadal/interdecadal scales is controlled mainly by the EASM, but not by the ISM. It is also suggested that the intensity of EASM is inversely related to that of the ISM on decadal/interdecadal scales. The decadal/interdecadal variability of ENSO may be responsible for the inverse relationship between the intensity of EASM and that of ISM. © 2007 Elsevier B.V. All rights reserved. Article 2007 English 00310182 10.1016/j.palaeo.2007.07.007 Palaeogeography, Palaeoclimatology, Palaeoecology 254 541 – 549 3-4 Asia; China; Eurasia; Far East; Qinghai; Qinghai Lake; climate variation; global climate; organic matter; precipitation assessment; stalagmite https://www.scopus.com/inward/record.uri?eid=2-s2.0-34548855031&doi=10.1016%2fj.palaeo.2007.07.007&partnerID=40&md5=7fbdd74a5e5e0904dc02568a65c00593 Cited by: 74 H. Xu Z.H. Hou L. Ai L.C. Tan article Mortimer2007393 The East African Rift system has long been considered the best modern example of the initial stages of continental rifting. The Malawi Rift is characteristic of the western branch of the East African Rift system, composed of half-grabens of opposing asymmetry along its length. There are striking similarities between basins within the Malawi Rift, and others along the western branch. Each exhibits similar bathymetry, border-fault length, rift zone width and fault segment length. The North Basin of the Malawi Rift differs from others in the rift only in its orientation: trending NW-SE as opposed to N-S. Although there is general agreement as to the geometry of the Malawi Rift; debate as to the amount of strike-slip vs. dip-slip deformation and the influence of underlying Pan-African foliation remains. This study presents new data from a closely spaced shallow [2 s two-way travel time (TWT)] seismic reflection data set integrated with basin-scale deeper (6 s TWT) seismic reflection data that document the structural evolution of the border and intra-basin faults. These data reveal that the different trend of the North Basin, most likely to have been influenced by the underlying Pan-African foliation, has played an extremely important role in the structural style of basin evolution. The border-fault and intra-basin structures nucleated during extension that was initially orthogonal (ENE). During this time (>8.6 to ∼0.5-0.4 Ma) intra-basin faults synthetic to the west-dipping border-fault nucleated, whereas strain was localised on the segmented border-fault early on. A later rotation of extension orientation (to NW) led to these established faults orienting oblique to rifting. This generated an overall dextral strike-slip setting that led to the development of transfer faults adjacent to the border-fault, and the generation of flower structures and folds over the greater displacement intra-basin faults. © © 2007 Blackwell Publishing Ltd. 2007 English 0950091X 10.1111/j.1365-2117.2007.00332.x Basin Research 19 393-407 Institute für Geowissenschaften, Universität Potsdam, Karl-Liebknecht Straße 24/25, Potsdam 14476, Germany; Department of Geology and Geological Engineering, Colorado School of Mines, Golden, CO, United States; Department of Earth Sciences, Syracuse University, Syracuse, NY, United States 3 basin evolution; displacement; rift zone; rifting; seismic data; strike-slip fault, Africa; East Africa; Malawi; Sub-Saharan Africa https://www.scopus.com/inward/record.uri?eid=2-s2.0-34548316616&doi=10.1111%2fj.1365-2117.2007.00332.x&partnerID=40&md5=117ce36fb1455284fd7e289f81ecb4ff cited By 57 E. Mortimer D.A. Paton C.A. Scholz M.R. Strecker P. Blisniuk article Šafanda2007423 As part of the International Continental Scientific Drilling Program (ICDP), the 1.5-km-deep borehole Yaxcopoil-1, located in the Chixculub meteor impact structure in Mexico, has undergone further study after drilling operations ceased. Temperature logs were repeated ten times at intervals 0.3-0.8, 15, 24 and 34 months after borehole shut-in. The logs bear a distinct signature of transient heat transfer by groundwater flow manifested by a gradual distortion of the linear temperature profile when acoldwaveof0.8-1.6°C amplitude was detected propagating downward from 145 to 312 m at a rate of 4-6 m/month. To understand the nature of this moving anomaly, a 20-day monitoring of the cold wave was carried out at a depth of 307 m that showed further cooling of 0.6°C during the first 16 days of the passage followed by temperature stabilisation. As an explanation of this unusual phenomenon, a theory is proposed, whereby the drilling mud has accumulated within the overlying and cooler highly porous and permeable karstic rocks during the drilling and migrates downward. The observed migration rate suggests a permeability higher than 10-11 m2. This indicates a high vulnerability to contamination of the only freshwater aquifer in the Yucatan region. © Springer-Verlag 2006. 2007 10.1007/s10040-006-0082-8 Hydrogeology Journal 15 423-428 Geophysical Institute, Boční II/1401, 14131 Prague, Czech Republic; Geophysical Institute, University Karlsruhe, Hertzstrasse 16, 76187 Karlsruhe, Germany 2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-65649098531&doi=10.1007%2fs10040-006-0082-8&partnerID=40&md5=f1a7a79479f1054af06c33d7b828ab5c cited By 8 J. Šafanda P. Heidinger H. Wilhelm V. Čermák article Karikari2007513 Samples of the country rocks that likely constituted the target rocks at the 1.07 Myr old Bosumtwi impact structure in Ghana, West Africa, collected outside of the crater rim in the northern and southern parts of the structure, were studied for their petrographic characteristics and analyzed for their major- and trace-element compositions. The country rocks, mainly meta-graywacke, shale, and phyllite of the Early Proterozoic Birimian Supergroup and some granites of similar age, are characterized by two generations of alteration. A pre-impact hydrothermal alteration, often along shear zones, is characterized by new growth of secondary minerals, such as chlorite, sericite, sulfides, and quartz, or replacement of some primary minerals, such as plagioclase and biotite, by secondary sericite and chlorite. A late, argillic alteration, mostly associated with the suevites, is characterized by alteration of the melt/glass clasts in the groundmass of suevites to phyllosilicates. Suevite, which occurs in restricted locations to the north and to the south-southwest of the crater rim, contains melt fragments, diaplectic quartz glass, ballen quartz, and clasts derived from the full variety of target rocks. No planar deformation features (PDFs) in quartz were found in the country rock samples, and only a few quartz grains in the suevite samples show PDFs, and in rare cases two sets of PDFs. Based on a total alkali element-silica (TAS) plot, the Bosumtwi granites have tonalitic to quartz-dioritic compositions. The Nb versus Y and Ta versus Yb discrimination plots show that these granites are of volcanic-arc tectonic provenance. Provenance studies of the metasedimentary rocks at the Bosumtwi crater have also indicated that the metasediments are volcanic-arc related. Compared to the average siderophile element contents of the upper continental crust, both country rocks and impact breccias of the Bosumtwi structure show elevated siderophile element contents. This, however, does not indicate the presence of an extraterrestrial component in Bosumtwi suevite, because the Birimian country rocks also have elevated siderophile element contents, which is thought to result from regional hydrothermal alteration that is also related to widespread sulfide and gold mineralization. © The Meteoritical Society, 2007. Printed in USA. Article 2007 English 10869379 10.1111/j.1945-5100.2007.tb01058.x Meteoritics and Planetary Science 42 University of Arkansas 513 – 540 4-5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-34250683440&doi=10.1111%2fj.1945-5100.2007.tb01058.x&partnerID=40&md5=13ea4c3df2f6edbbedca6660981650a4 Cited by: 24 Forson Karikari Ludovic Ferrière Christian Koeberl Wolf Uwe Reimold Dieter Mader article Melles200789 The ca. 13 m long sediment core PG1351, recovered in 1998 from the central part of Lake El'gygytgyn, NE Siberia, was investigated for lithostratigraphy, water content, dry bulk density (DBD), total organic carbon (TOC), total nitrogen (TN), total sulphur (TS) and biogenic silica (opal) contents, and for TOC stable isotope ratios (δ13CTOC). The event stratigraphy recorded in major differences in sediment composition match variations in regional summer insolation, thus confirming a new age model for this core, which suggests that it spans the last 250 ka BP. Four depositional units of contrasting lithological and biogeochemical composition have been distinguished, reflecting past environmental conditions associated with relatively warm, peak warm, cold and dry, and cold but more moist climate modes. A relatively warm climate, resulting in complete summer melt of the lake ice cover and seasonal mixing of the water column, prevailed during the Holocene and Marine Isotope Stages (MIS) 3, 5.1, 5.3, 6.1, 6.3, 6.5, 7.1-7.3, 7.5, 8.1 and 8.3. MIS 5.5 (Eemian) was characterized by significantly enhanced aquatic primary production and organic matter supply from the catchment, indicating peak warm conditions. During MIS 2, 5.2, 5.4, 6.2 and 6.4 the climate was cold and dry, leading to perennial lake ice cover, little regional snowfall, and a stagnant water body. A cold but more moist climate during MIS 4, 6.6, 7.4, 8.2 and 8.4 is thought to have produced more snow cover on the perennial ice, strongly reducing light penetration and biogenic primary production in the lake. While the cold-warm pattern during the past three glacial-interglacial cycles is probably controlled by changes in regional summer insolation, differences in the intensity of the warm phases and in the degree of aridity (changing snowfall) during cold phases likely were due to changes in atmospheric circulation patterns. © 2006 Springer Science+Business Media B.V. 2007 English 09212728 10.1007/s10933-006-9025-6 Journal of Paleolimnology 37 89-104 Institute for Geophysics and Geology, University Leipzig, Talstrasse 35, D-04103 Leipzig, Germany; Department of Geosciences, University of Massachusetts, Morrill Science Building, Amherst, MA 01003, United States; North East Interdisciplinary Research Institute, Far East Branch, Russian Academy of Sciences, 16 Portovaya Street, 685000 Magadan, Russian Federation; GeoForschungsZentrum, Telegrafenberg C321, D-14473 Potsdam, Germany; Alfred Wegener Institute for Polar and Marine Research, Research Unit Potsdam, Telegrafenberg A43, D-14473 Potsdam, Germany 1 climate variation; geochemistry; glacial-interglacial cycle; Holocene; insolation; marine isotope stage; paleoclimate; paleolimnology; sediment core, Chukchi; Eurasia; Lake El'gygytgyn; Russian Federation https://www.scopus.com/inward/record.uri?eid=2-s2.0-33845963701&doi=10.1007%2fs10933-006-9025-6&partnerID=40&md5=a2739ac08d9c685a61ef33d6f2e2e258 cited By 98 M. Melles J. Brigham-Grette O.Yu. Glushkova P.S. Minyuk N.R. Nowaczyk H.-W. Hubberten article Abramov200793 Large impact events like the one that formed the Chicxulub crater deliver significant amounts of heat that subsequently drive hydrothenmal activity. We report on numerical modeling of Chicxulub crater cooling with and without the presence of water. The model inputs are constrained by data from borehole samples and seismic, magnetic, and gravity surveys. Model results indicate that initial hydrothermal activity was concentrated beneath the annular trough as well as in the permeable breccias overlying the melt. As the system evolved, the melt gradually cooled and became permeable, shifting the bulk of the hydrothermal activity to the center of the crater. The temperatures and fluxes of fluid and vapor derived from the model are consistent with alteration patterns observed in the available borehole samples. The lifetime of the hydrothermal system ranges from 1.5 to 2.3 Myr depending on assumed permeability. The long lifetimes are due to conduction being the dominant mechanism of heat transport in most of the crater, and significant amounts of heat being delivered to the near-surface by hydrothermal upwellings. The long duration of the hydrothermal system at Chicxulub should have provided ample time for colonization by thermophiles and/or hyperthermophiles. Because habitable conditions should have persisted for longer time in the central regions of the crater than on the periphery, a search for prospective biomarkers is most likely to be fruitful in samples from that region. © The Meteoritical Society, 2007. 2007 10.1111/j.1945-5100.2007.tb00220.x Meteoritics and Planetary Science 42 93-112 Lunar Planetary Laboratory, The University of Arizona, 1629 East University Boulevard, Tucson, AZ 85721-0092, United States; Department of Space Studies, Southwest Research Institute, 1050 Walnut Street, Boulder, CO 80302, United States; Lunar and Planetary Institute, 3600 Bay Area Boulevard, Houston, TX 77058, United States 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-33846436763&doi=10.1111%2fj.1945-5100.2007.tb00220.x&partnerID=40&md5=ca89f6d57dcbb831e13edce5136ebf7f cited By 78 O. Abramov D.A. Kring article Deutsch2007155 In context of the “K/T” Chicxulub cratering event, the amounts of impact-released CO2and SOxas well as the consequences of this gaseous input into the atmosphere are discussed. It has been assumed that degassing of the sediments is an abrupt and violent effect, only related to the amplitude of the post-shock temperature after pressure decay. Here we provide evidence for a different, slow and probably equally important process of devolatilization: degassing and dissociation of sedimentary clasts in impact breccias. The sulfate and carbonate clasts in suevites, melt breccias, and melt rocks from the Chicxulub drill cores Y-6, C-1, and YAX-1, underwent various thermal effects, ranging from solid state re-crystallization over reaction with silicate melt to form pyroxene (diopside), melting (and re-crystallization) to total decomposition with dissolution of the lime in the melt matrix. These features reflect high, yet different formation temperatures of the breccias, and to a smaller degree, the fragment size. © 1996 Scandinavian University Press. 2007 10.1080/11035890701292155 GFF 129 155-160 Institut für Planetologie (IfP), Westfälische Wilhelms-Universität Münster (WWU), Wilhelm-Klemm-Str. 10, Münster, D-48149, Germany; Institut für Geowissenschaften, Friedrich-Schiller-Universität Jena, Burgweg 11, Jena, D-07749, Germany 2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-34547116853&doi=10.1080%2f11035890701292155&partnerID=40&md5=b1231327ec11f9dba855630773096122 cited By 18 A. Deutsch F. Langenhorst article Fekiacova200765 The "Ko'olau" component of the Hawaiian mantle plume represents an extreme (EM1-type) end member of Hawaiian shield lavas in radiogenic isotope space, and was defined on the basis of the composition of subaerial lavas exposed in the Makapu'u section of Ko'olau Volcano. The 679 m-deep Ko'olau Scientific Drilling Project (KSDP) allows the long-term evolution of Ko'olau Volcano to be reconstructed and the longevity of the "Ko'olau" component in the Hawaiian plume to be tested. Here, we report triple spike Pb isotope and Sr and Nd isotope data on KSDP core samples, and rejuvenation stage Honolulu Volcanics (HV) (together spanning ∼ 2.8 m.y.), and from ∼ 110 Ma basalts from ODP Site 843, thought to be representative of the Pacific lithosphere under Hawai'i. Despite overlapping ranges in Pb isotope ratios, KSDP and HV lavas form two distinct linear arrays in 208Pb/204Pb-206Pb/204Pb isotope space. These arrays intersect at the radiogenic end indicating they share a common component. This "Kalihi" component has more radiogenic Pb, Nd, Hf, but less radiogenic Sr isotope ratios than the "Makapu'u" component. The mixing proportions of these two components in the lavas oscillated through time with a net increase in the "Makapu'u" component upsection. Thus, the "Makapu'u" enriched component is a long-lived feature of the Hawaiian plume, since it is present in the main shield-building stage KSDP lavas. We interpret the changes in mixing proportions of the Makapu'u and Kalihi components as related to changes in both the extent of melting as well as the lithology (eclogite vs. peridotite) of the material melting as the volcano moves away from the plume center. The long-term Nd isotope trend and short-term Pb isotope fluctuations seen in the KSDP record cannot be ascribed to a radial zonation of the Hawaiian plume: rather, they reflect the short length-scale heterogeneities in the Hawaiian mantle plume. Linear Pb isotope regressions through the HV, recent East Pacific Rise MORB and ODP Site 843 datasets are clearly distinct, implying that no simple genetic relationship exists between the HV and the Pacific lithosphere. This observation provides strong evidence against generation of HV as melts derived from the Pacific lithosphere, whether this be recent or old (100 Ma). The depleted component present in the HV is unlike any MORB-type mantle and most likely represents material thermally entrained by the upwelling Hawaiian plume and sampled only during the rejuvenated stage. The "Kalihi" component is predominant in the main shield building stage lavas but is also present in the rejuvenated HV. Thus this material is sampled throughout the evolution of the volcano as it moves from the center (main shield-building stage) to the periphery (rejuvenated stage) of the plume. The presence of a plume-derived material in the rejuvenated stage has significant implications for Hawaiian mantle plume melting models. © 2007 Elsevier B.V. All rights reserved. 2007 English 0012821X 10.1016/j.epsl.2007.06.005 Earth and Planetary Science Letters 261 65-83 Max-Planck-Institut für Chemie, Abteilung Geochemie, Postfach 3060, 55020 Mainz, Germany; Department of Geology and Geophysics, University of Hawai'i, Manoa, Honolulu, Hawai'i 96822, United States 1-2 Lithosphere; Mantle plumes; Radial zonation, Isotopes; Lithology; Melting; Seismology; Volcanic rocks, Volcanoes, basalt; igneous geochemistry; isotopic composition; lava; lead isotope; mantle plume; neodymium isotope; Ocean Drilling Program; strontium isotope; volcanic rock, Hawaii [United States]; Hawaiian Islands; Koolau; North America; Oahu; Pacific islands; Pacific Ocean; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-34548207227&doi=10.1016%2fj.epsl.2007.06.005&partnerID=40&md5=18a1a57295d61af4737da19663a3ac1e cited By 71 Z. Fekiacova W. Abouchami S.J.G. Galer M.O. Garcia A.W. Hofmann article Brigham-Grette20071 Sediment piston cores from Lake El'gygytgyn (67°N, 172°E), a 3.6 million year old meteorite impact crater in northeastern Siberia, have been analyzed to extract a multi-proxy millennial-scale climate record extending to nearly 250 ka, with distinct fluctuations in sedimentological, physical, biochemical, and paleoecological parameters. Five major themes emerge from this research. First the pilot cores and seismic data show that El'gygytygn Crater Lake contains what is expected to be the longest, most continuous terrestrial record of past climate change in the entire Arctic back to the time of impact. Second, processes operating in the El'gygytygn basin lead to changes in the limnogeology and the biogeochemistry that reflect robust changes in the regional climate and paleoecology over a large part of the western Arctic. Third, the magnetic susceptibility and other proxies record numerous rapid change events. The recovered lake sediment contains both the best-resolved record of the last interglacial and the longest terrestrial record of millennial scale climate change in the Arctic, yielding a high fidelity multi-proxy record extending nearly 150,000 years beyond what has been obtained from the Greenland Ice Sheet. Fourth, the potential for evaluating teleconnections under different mean climate states is high. Despite the heterogeneous nature of recent Arctic climate change, millennial scale climate events in the North Atlantic/Greenland region are recorded in the most distal regions of the Arctic under variable boundary conditions. Finally, deep drilling of the complete depositional record in Lake El'gygytgyn will offer new insights and, perhaps, surprises into the late Cenozoic evolution of Arctic climate. © 2006 Springer Science+Business Media B.V. 2007 English 09212728 10.1007/s10933-006-9017-6 Journal of Paleolimnology 37 1-16 Dept. of Geosciences, University of Massachusetts, Amherst, MA 01003, United States; Institute for Geology and Geophysics, University of Leipzig, Leipzig, Germany; North-East Interdisciplinary Science Research Institute FEB RAS, 16 Portovaya St., 685000 Magadan, Russian Federation 1 arctic environment; climate change; core analysis; crater lake; paleoclimate; paleolimnology; proxy climate record; seismic data, Chukchi; Eurasia; Lake El'gygytgyn; Russian Federation https://www.scopus.com/inward/record.uri?eid=2-s2.0-33845922436&doi=10.1007%2fs10933-006-9017-6&partnerID=40&md5=ff62392875f0c19c3671fbe0d2b65a68 cited By 67 J. Brigham-Grette M. Melles P. Minyuk article Kontny2007811 Rock magnetic and magnetic mineralogy data are presented from the International Continental Scientific Drilling Program (ICDP) drill cores LB-07A and LB-08A of the Bosumtwi impact structure in order to understand the magnetic behavior of impact and target lithologies and their impact-related remagnetization mechanism. Basic data for the interpretation of the magnetic anomaly patterns and the magnetic borehole measurements as well as for new magnetic modeling are provided. Magnetic susceptibility (150-500 × 10-6 SI) and natural remanent magnetization (10-3-10-1 A/m) are generally weak, but locally higher values up to 10.6 × 10-3 SI and 43 A/m occur. Sixty-three percent of the investigated rock specimens show Q values above 1 indicating that remanence clearly dominates over induced magnetization, which is a typical feature of impact structures. Ferrimagnetic pyrrhotite is the main magnetite phase, which occurs besides minor magnetite and a magnetic phase with a Curie temperature between 330 and 350 °C, interpreted as anomalous pyrrhotite. Coercive forces are between 20 and 40 mT. Brecciation and fracturing of pyrrhotite is a common feature confirming its pre-impact origin. Grain sizes of pyrrhotite show a large variation but the numerous stress-induced nanostructures observable by transmission electron microscopy (TEM) are assumed to behave as single-domain grains. We suggest that the drilled rocks lost their pre-shock remanence memory during the shock event and acquired a new, stable remanence during shock-induced grain size reduction. The observed brittle microstructures indicate temperatures not higher than 250 °C, which is below the Curie temperature of ferrimagnetic pyrrhotite (310 °C). © The Meteoritical Society, 2007. Printed in USA. Article 2007 English 10869379 10.1111/j.1945-5100.2007.tb01077.x Meteoritics and Planetary Science 42 University of Arkansas 811 – 827 4-5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-34250643137&doi=10.1111%2fj.1945-5100.2007.tb01077.x&partnerID=40&md5=fc936dee77ac0b53b2bc4806b17786a1 Cited by: 25; All Open Access, Bronze Open Access Agnes Kontny Tiiu Elbra Jana Just Lauri J. Pesonen Anja M. Schleicher Jochen Zolk article Geissler200733 New petrological and geochemical data of upper mantle and lower crustal xenoliths from a Quaternary tephra deposit in Mýtina, Czech Republic, are discussed in the frame of previous geophysical results (receiver functions, reflection seismology) of the western Eger/Ohře Rift area. The Vogtland/NW Bohemia region is well known for intraplate earthquake swarms, which are usually associated with volcanic activity. As previously reported, 3He/4He data of CO2 emissions in mofettes and mineral-water springs point at ongoing magmatic processes in this area. Using teleseismic P receiver functions, an approximately 40-km-wide Moho updoming (from 31 to 27 km) and indications for a seismic discontinuity at 50 to 60 km depth were observed beneath the active CO2-degassing field. The studied xenolith suite probes a lithospheric profile within the structural and gas geochemical anomaly field of the western Eger Rift. With regard to texture, composition, p-T estimates and origin, five xenolith groups can be discriminated. Upper crustal xenoliths (quartzites, phyllites, mica schists) resemble crystalline country rocks at surface. One noritic xenolith (6 kbar, 800 °C) could represent a sample of the lower crust. Clinopyroxenites and hornblendites probably represent cumulates of the nephelinitic magma or fragments of magmatic veins. Porous wehrlites and one hornblende peridotite xenolith reflect a metasomatied upper mantle. Megacrysts of Ti-rich amphibole, olivine, clinopyroxene, and phlogopite could be fragments of pegmatitic veins or high-pressure phenocrysts. Most of the ultramafic nodules (xenoliths and megacrysts) formed at pressures between 6 and 11 kbar (22 to 38 km depth), at temperatures well above regional geotherms of the Bohemian Massif calculated from surface heat flow studies. Orthopyroxene-bearing spinel-lherzolite xenoliths were not observed. Our petrographical, geochemical, and thermobarometric results indicate a lithospheric mantle strongly altered by magmatic processes. This metasomatism can cause slower than typical uppermost-mantle seismic velocities in a greater area and might help to explain observed seismic anomalies. © 2006 Elsevier B.V. All rights reserved. Article 2007 English 03770273 10.1016/j.jvolgeores.2006.06.011 Journal of Volcanology and Geothermal Research 159 33 – 69 1-3 Bohemia; Central Europe; Czech Republic; Eger; Eurasia; Europe; Germany; Heves; Hungary; Vogtland; Barometers; Earthquakes; Geothermal fields; Lithology; Petrology; Seismology; Thermometers; Volcanic rocks; earthquake swarm; lithosphere; mantle chemistry; Moho; petrology; Quaternary; seismic velocity; teleseismic wave; tephra; upper mantle; xenolith; Earthquake swarm region; Lithosphere; Quaternary volcanism; Seismic structure; Volcanoes https://www.scopus.com/inward/record.uri?eid=2-s2.0-33845566745&doi=10.1016%2fj.jvolgeores.2006.06.011&partnerID=40&md5=b53cd442f76ed88dee05c5cd32a6274c Cited by: 30 W.H. Geissler H. Kämpf W. Seifert P. Dulski article Artemieva2007883 Pre-drilling numerical modeling of the Bosumtwi impact event predicted a 200 m thick coherent melt layer, as well as abundant highly shocked target material within the central part of the crater structure. However, these predictions are in disagreement with data from drill core obtained in 2004-2005. Here I provide a brief overview of previous results and discuss possible reasons behind melt deficiency, such as specific impact scenarios (low impact velocity and/or low impact angle), and specific target properties (different composition, high porosity, high content of volatiles). I conclude that the most likely explanation is the dispersion of impactites due to the vaporization of pore water, which was not included in the original numerical model. © The Meteoritical Society, 2007. Printed in USA. 2007 10.1111/j.1945-5100.2007.tb01083.x Meteoritics and Planetary Science 42 883-894 Institute for Dynamics of Geospheres, Leninsky Prospect 38, 119334 Moscow, Russian Federation; Planetary Science Institute, 1700 East Fort Lowell, Tucson, AZ 85719, United States 4-5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-34250642321&doi=10.1111%2fj.1945-5100.2007.tb01083.x&partnerID=40&md5=f2e1cc99158466407479c5270ed72b8b cited By 23 N. Artemieva article Elbra2007829 Physical properties from rocks of the Bosumtwi impact structure, Ghana, Central Africa, are essential to understand the formation of the relatively young (1.07 Ma) and small (10.5 km) impact crater and to improve its geophysical modeling. Results of our petrophysical studies of deep drill cores LB-07A and LB-08A reveal distinct lithological patterns but no depth dependence. The most conspicuous difference between impactites and target lithologies are the lower bulk densities and significantly higher porosities of the suevite and lithic breccia units compared to meta-graywacke and metapelites of target lithologies. Magnetic susceptibility shows mostly paramagnetic values (200-500 × 10-6 SI) throughout the core, with an exception of a few metasediment samples, and correlates positively with natural remanent magnetization (NRM) and Q values. These data indicate that magnetic parameters are related to inhomogeneously distributed ferrimagnetic pyrrhotite. The paleomagnetic data reveals that the characteristic direction of NRM has shallow normal (in a few cases shallow reversed) polarity, which is in agreement with the Lower Jaramillo N-polarity chron direction, and is carried by ferrimagnetic pyrrhotite. However, our study has not revealed the expected high magnetization body required from previous magnetic modeling. Furthermore, the LB-07A and LB08-A drill cores did not show the predicted high content of melt in the rocks, requiring a new interpretation model for magnetic data. © The Meteoritical Society, 2007. Printed in USA. Article 2007 English 10869379 10.1111/j.1945-5100.2007.tb01078.x Meteoritics and Planetary Science 42 University of Arkansas 829 – 838 4-5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-34250637525&doi=10.1111%2fj.1945-5100.2007.tb01078.x&partnerID=40&md5=d6e68467e6c2888bb8d7ee4a2c56e562 Cited by: 20; All Open Access, Bronze Open Access Tiiu Elbra Agnes Kontny Lauri J. Pesonen Norbert Schleifer Christina Schell article Morris2007801 Physical rock property measurements provide the primary constraints for any geological models hypothesized from geophysical observations. Previous geophysical models of the Bosumtwi impact structure hypothesized that a highly magnetic and dense impact-melt sheet might be the source of the observed magnetic anomalies. However, magnetic susceptibility and density measurements made on International Continental Scientific Drilling Program (ICDP) cores LB-07A and LB-08A from the interior of the Bosumtwi meteorite impact structure contain no evidence for that. Both density and magnetic susceptibility logs on both boreholes exhibit low-amplitude contrasts between the uppermost polymict lithic breccia and suevite, the intermediate monomict lithic breccia, and the lowermost bedrock. The depth extent of fracture-related density reduction is much greater at LB-08A than at LB-07A. A total magnetic intensity log from borehole LB-08A supports the suggestion that magnetic anomalies over Lake Bosumtwi are mainly sourced in undetected and/or covered bedrock intrusions, like the ones outcropping at the northeast and to the southwest of the lake. © The Meteoritical Society, 2007. Printed in USA. Article 2007 English 10869379 10.1111/j.1945-5100.2007.tb01076.x Meteoritics and Planetary Science 42 University of Arkansas 801 – 809 4-5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-34250618300&doi=10.1111%2fj.1945-5100.2007.tb01076.x&partnerID=40&md5=9c64ab19c47759edb1ed8284b8e4ae0a Cited by: 9 William A. Morris Hernan Ugalde Christina Clark article Fietz2007177 Lake Baikal, an ancient pristine lake in Siberia, has accumulated sediment deposits that span 25 million years. These deposits have the potential to provide a long-term record of climate changes and their interaction with the ecology of the lake. In order to investigate whether sedimentary phytoplankton pigments could be used to reconstruct past changes in total phytoplankton abundance and productivity, we compared the spatial variability in sedimentary pigment distributions in Holocene cores from three separate regions of the lake; Vidrino in the south, Posolski on Selenga Delta and Continent Ridge in the north. Furthermore, we present the first continuous sedimentary pigment and organic carbon sequence of the Kazantsevo interglacial (roughly a time equivalent to the European Eemian, and Marine Isotopic Stage MIS5e) at a resolution of approximately 150 years. Results of the spatial study showed marked differences in the sediment pigment deposition. Lowest chlorophyll a plus its degradation products versus organic carbon ratios (Chlas/TOC) indicating lowest production, but highest variability with time (indicating strongest climatic oscillations) were found at Continent Ridge. The study of sedimentary pigments deposited during the last two interglacial periods at Continent Ridge showed Chlas/TOC ratios 50-1000 times higher during the Kazantsevo Interglacial compared to the glacial periods, whereas the TOC content was only five times higher, thus indicating the significance of the Chlas/TOC ratio for the reconstruction of the phytoplankton abundance and productivity. Strong oscillations occurred during the Kazantsevo Interglacial within centennial time scales. Chlorophyllb plus its degradation products provided additional information on the past development of Chlorophyceae. Highest Chlas/TOC ratios were found during the early Holocene at approximately 9 kyr BP. Indications of short phytoplankton production maxima were also found during the late Atlantic (6 kyr BP) and at the Subboreal/Subatlantic transition (3 kyr BP). From this we conclude that sedimentary chlorophyll a is a reliable indicator of phytoplanktonic response to climate changes and may serve for validation of future climate scenarios in continental regions. © 2006 Springer Science+Business Media B.V. Article 2007 English 09212728 10.1007/s10933-006-9012-y Journal of Paleolimnology 37 177 – 203 2 Buryatia; Eurasia; Lake Baikal; Russian Federation; Selenga Delta; Bacillariophyta; Chlorophyceae; abundance; chlorophyll; climate change; Holocene; interglacial; lacustrine deposit; organic carbon; paleoecology; phytoplankton; pigment; pristine environment https://www.scopus.com/inward/record.uri?eid=2-s2.0-33846426500&doi=10.1007%2fs10933-006-9012-y&partnerID=40&md5=4f5b831020718dcef7053dcfaf1a5a3a Cited by: 27 Susanne Fietz Andreas Nicklisch Hedi Oberhänsli article Goderis2007731 In an attempt to identify the type of projectile, 14 samples from the Bosumtwi crater in Ghana were analyzed for platinum group element (PGE) concentrations by nickel sulfide fire assay inductively coupled plasma-mass spectrometry (ICP-MS). The majority of the samples come from the impactite material recovered by cores LB-07A and LB-08A, which were drilled by the International Continental Scientific Drilling program (ICDP). One sample originates from the fallback material found at the contact between the impactite and the overlying lake sediment in core LB-05B. No clear signature of a meteoritic contamination was identified in the 13 impactite samples. The target rock apparently dominates the PGE contribution in the impactites. These results agree with the PGE concentrations reported for the suevites collected at the crater rim and in other parts of the Bosumtwi ICDP cores. However, based on Cr and Os isotopic signatures, a meteoritic component could be present in the sample of fallback material, supporting the reports of the existence of meteoritic material in the Ivory Coast tektites. Further analyses of the fallback material from the Bosumtwi drill cores should confirm (or not) this first result. © The Meteoritical Society, 2007. Printed in USA. Article 2007 English 10869379 10.1111/j.1945-5100.2007.tb01070.x Meteoritics and Planetary Science 42 University of Arkansas 731 – 741 4-5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-34250635058&doi=10.1111%2fj.1945-5100.2007.tb01070.x&partnerID=40&md5=457f83b4d36929ae843896d436d3eb39 Cited by: 17; All Open Access, Green Open Access S. Goderis R. Tagle R.T. Schmitt J. Erzinger Ph. Claeys article Goderis2007731 In an attempt to identify the type of projectile, 14 samples from the Bosumtwi crater in Ghana were analyzed for platinum group element (PGE) concentrations by nickel sulfide fire assay inductively coupled plasma-mass spectrometry (ICP-MS). The majority of the samples come from the impactite material recovered by cores LB-07A and LB-08A, which were drilled by the International Continental Scientific Drilling program (ICDP). One sample originates from the fallback material found at the contact between the impactite and the overlying lake sediment in core LB-05B. No clear signature of a meteoritic contamination was identified in the 13 impactite samples. The target rock apparently dominates the PGE contribution in the impactites. These results agree with the PGE concentrations reported for the suevites collected at the crater rim and in other parts of the Bosumtwi ICDP cores. However, based on Cr and Os isotopic signatures, a meteoritic component could be present in the sample of fallback material, supporting the reports of the existence of meteoritic material in the Ivory Coast tektites. Further analyses of the fallback material from the Bosumtwi drill cores should confirm (or not) this first result. © The Meteoritical Society, 2007. Printed in USA. 2007 10.1111/j.1945-5100.2007.tb01070.x Meteoritics and Planetary Science 42 731-741 Department of Geology, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium; Department of Geology and Soil Science, Ghent University, Krijgslaan 281, 9000 Ghent, Belgium; Department of Mineralogy, Natural History Museum Berlin, 10099 Berlin, Germany; GeoForschungsZentrum Potsdam, 14473 Potsdam, Germany 4-5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-34250635058&doi=10.1111%2fj.1945-5100.2007.tb01070.x&partnerID=40&md5=457f83b4d36929ae843896d436d3eb39 cited By 17 S. Goderis R. Tagle R.T. Schmitt J. Erzinger Ph. Claeys article Glushkova200737 Geomorphic, lithologhic, and stratigraphic field studies as well as pollen data and mineralogical study have been used to propose Pliocene and Pleistocene paleogeographic reconstructions of the El'gygytgyn meteorite crater area. The moment of impact is recorded above the early Pliocene hill denudation plain as a "chaotic horizon" consisting of fragments of impactite rocks. This chaotic horizon lies between layers of late Pliocene alluvial sediments. During the second half of the late Pliocene, the region was tectonically active, when the Anadyr lowland was uplifted causing alluvial sediments to accumulate in the basins to the south of the crater. Regional climatic cooling, which supported the spread of tundra and the formation of permafrost is characteristically to late Pliocene. The 35-40 m high terrace that roughly follows the 530 m contour interval along the Enmyvaam River formed during the middle Pleistocene. This terrace represents the maximum lake level. Erosion and incision of the upper Enmyvaam River increased due to another wave of uplift. Additionally, El'gygytgyn Lake discharge increased causing lake level to begin to drop in the Middle Pleistocene. Cooling continued, which led to the development of herb-dominated arctic tundra. middle and late Pleistocene glaciations did not reach the El'gygytgyn lake region. The 9-11 m high lacustrine terrace was formed around the lake during the late Pleistocene and the 2-3 m high lacustrine terrace formed later during the Holocene. During the last 5000 years, the lake level has continued to drop as the modern coastline developed. © 2006 Springer Science+Business Media B.V. 2007 English 09212728 10.1007/s10933-006-9021-x Journal of Paleolimnology 37 37-47 North-East Interdisciplinary Scientific Research Institute FEB RAS, 16 Portovaya Street, 685000 Magadan, Russian Federation 1 chronology; crater lake; Holocene; lacustrine environment; lake evolution; lake level; paleogeography; Pleistocene; Pliocene; pollen; terrace, Chukchi; Eurasia; Lake El'gygytgyn; Russian Federation, Zanclea https://www.scopus.com/inward/record.uri?eid=2-s2.0-33845954776&doi=10.1007%2fs10933-006-9021-x&partnerID=40&md5=cac5a7047e52048976f395bc6e160012 cited By 48 O.Yu. Glushkova V.N. Smirnov article Artemieva2007883 Pre-drilling numerical modeling of the Bosumtwi impact event predicted a 200 m thick coherent melt layer, as well as abundant highly shocked target material within the central part of the crater structure. However, these predictions are in disagreement with data from drill core obtained in 2004-2005. Here I provide a brief overview of previous results and discuss possible reasons behind melt deficiency, such as specific impact scenarios (low impact velocity and/or low impact angle), and specific target properties (different composition, high porosity, high content of volatiles). I conclude that the most likely explanation is the dispersion of impactites due to the vaporization of pore water, which was not included in the original numerical model. © The Meteoritical Society, 2007. Printed in USA. Article 2007 English 10869379 10.1111/j.1945-5100.2007.tb01083.x Meteoritics and Planetary Science 42 University of Arkansas 883 – 894 4-5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-34250642321&doi=10.1111%2fj.1945-5100.2007.tb01083.x&partnerID=40&md5=f2e1cc99158466407479c5270ed72b8b Cited by: 23 N. Artemieva article McDonald2007743 An attempt was made to detect a meteoritic component in both crater-fill (fallback) impact breccias and fallout suevites (outside the crater rim) at the Bosumtwi impact structure in Ghana. Thus far, the only clear indication for an extraterrestrial component related to this structure has been the discovery of a meteoritic signature in Ivory Coast tektites, which formed during the Bosumtwi impact event. Earlier work at Bosumtwi indicated unusually high levels of elements that are commonly used for the identification of meteoritic contamination (i.e., siderophile elements, including the platinum group elements [PGE]) in both target rocks and impact breccias from surface exposures around the crater structure, which does not allow unambiguous verification of an extraterrestrial signature. The present work, involving PGE abundance determinations and Os isotope measurements on drill core samples from inside and outside the crater rim, arrives at the same conclusion. Despite the potential of the Os isotope system to detect even small amounts of extraterrestrial contribution, the wide range in PGE concentrations and Os isotope composition observed in the target rocks makes the interpretation of unradiogenic, high-concentration samples as an impact signature ambiguous. © The Meteoritical Society, 2007. Printed in USA. Article 2007 English 10869379 10.1111/j.1945-5100.2007.tb01071.x Meteoritics and Planetary Science 42 University of Arkansas 743 – 753 4-5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-34250666645&doi=10.1111%2fj.1945-5100.2007.tb01071.x&partnerID=40&md5=0616ff4d98855dbd803b5bd9a7dec152 Cited by: 21; All Open Access, Bronze Open Access Iain McDonald Bernhard Peucker-Ehrenbrink Louise Coney Ludovic Ferrière Wolf Uwe Reimold Christian Koeberl book Zoback2007649 The objective of fault-zone drilling projects is to directly study the physical and chemical processes that control deformation and earthquake generation within active fault zones. An enormous amount of field, laboratory, and theoretical work has been directed toward the mechanical and hydrological behavior of faults over the past several decades. Nonetheless, it is currently impossible to differentiate between - or even adequately constrain - the numerous conceptual models of active faults proposed over the years. For this reason, the Earth science community is left in the untenable position of having no generally accepted paradigm for the mechanical behavior of faults at depth. One of the primary causes for this dilemma is the difficulty of either directly observing or inferring physical properties and deformation mechanisms along faults at depth, as well as the need to observe directly key parameters such as the state of stress acting on faults at depth, pore fluid pressure (and its possible variation in space and time), and processes associated with earthquake nucleation and rupture. Today, we know very little about the composition of active faults at depth, their constitutive properties, the state of in situ stress or pore pressure within fault zones, the origin of fault-zone pore fluids, or the nature and significance of time-dependent fault-zone processes. © 2007 Elsevier B.V. All rights reserved. 2007 English 9780444527486 10.1016/B978-044452748-6.00084-5 Treatise on Geophysics 4 Elsevier 649-674 Stanford University, Stanford, CA, United States; US Geological Survey, Menlo Park, CA, United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-58149330148&doi=10.1016%2fB978-044452748-6.00084-5&partnerID=40&md5=745d5b70d046f18edd58d31298b148bf cited By 38 M.D. Zoback S. Hickman W. Ellsworth article Asikainen2007105 El'gygytgyn Crater Lake, NE Siberia was investigated for sedimentological proxies for regional climate change with a focus on the past 65 ka. Sedimentological parameters assessed relative to magnetic susceptibility include stratigraphy, grain size, clay mineralogy and crystallinity. Earlier work suggests that intervals of high susceptibility in these sediments are coincident with warmer (interglacial-like) conditions and well-mixed oxygenated bottom waters. In contrast, low susceptibility intervals correlate with cold (glacial-like) conditions when perennial ice-cover resulted in anoxia and the dissolution of magnetic carrier minerals. The core stratigraphy contains both well-laminated to non-laminated sequences. Reduced oxygen and lack of water column mixing preserved laminated sequences in the core. A bioturbation index based upon these laminated and non- laminated sequences co-varies with total organic carbon (TOC) and magnetic susceptibility. Clay mineral assemblages include illite, highly inter-stratified illite/smectite, and chlorite. Under warm or hydrolyzing conditions on the landscape around the lake, chlorite weathers easily and illite/smectite abundance increase, which produces an inverse relationship in the relative abundance of these clays. Trends in relative abundance show distinct down-core changes that correlate with shifts in susceptibility. The mean grain-size (6.92 μm) is in the silt-size fraction, with few grains larger than 65 μm. Terrigenous input to the lake comes from over 50 streams that are filtered through storm berms, which limits clastic deposition into the lake system. The sedimentation rate and terrigenous input grain-size is reduced during glacial intervals. Measurements of particle-size distribution indicate that the magnetic susceptibility fluctuations are not related to grain size. Lake El'gygytgyn's magnetic susceptibility and clay mineralogy preserves regional shifts in climate including many globally recognized events like the Younger Dryas and Bolling/Allerod. The sedimentary deposits reflect the climatic transitions starting with MIS4 through the Holocene transition. This work represents the first extensive sedimentological study of limnic sediment proxies of this age from Chukotka (Fig. 1). © 2006 Springer Science+Business Media B.V. 2007 English 09212728 10.1007/s10933-006-9026-5 Journal of Paleolimnology 37 105-122 Department of Geosciences, University of Massachusetts, Amherst, MA 01003, United States; Centre Eau, Terre et Environnement, Institut National de la Recherche Scientifique, Québec, Que. G1K 9A9, Canada 1 bioturbation; clay mineral; climate change; crater lake; grain size; lacustrine deposit; paleoclimate; proxy climate record; sedimentology, Chukchi; Eurasia; Lake El'gygytgyn; Russian Federation https://www.scopus.com/inward/record.uri?eid=2-s2.0-33845939919&doi=10.1007%2fs10933-006-9026-5&partnerID=40&md5=3afc2cb8fb7a02d7fb1850d6a777d763 cited By 57 C.A. Asikainen P. Francus J. Brigham-Grette article Zhang2007 We developed a three-dimensional (3D) shear-wave splitting tomography method to image the spatial anisotropy distribution by back projecting shear wave splitting delay times along ray paths derived from a 3D shear velocity model, assuming the delay times are accumulated along the ray paths. The local strength of the anisotropy is indicated by a parameter of anisotropy percentage, K. Using the shearwave splitting delay times for 575 earthquakes measured at PASO and HRSN stations, we imaged a detailed 3D anisotropy percentage model around the San Andreas Fault Observatory at Depth (SAFOD). The anisotropy percentage model shows strong heterogeneities, consistent with the strong spatial variations in both measured delay times and fast polarization directions. The San Andreas Fault (SAF) zone is highly anisotropic down to a depth of ∼4 km and then becomes less anisotropic at greater depths. Outside the fault zone, the highly anisotropic zone extends as deep as ∼7 km, consistent with the systematic depth dependence of the average time delays. To the southwest of the SAF, the Salinian granitic block shows relatively strong anisotropic: anomalies that are presumably caused by aligned microcracks consistent with the direction of the regional maximum compressive horizontal stress. To the northeast of the fault zone, a strong anisotropic anomaly between depths ∼2 and ∼4 km corresponds to a serpentinite body sandwiched between Franciscan rocks. Copyright 2007 by the American Geophysical Union. 2007 English 00948276 10.1029/2007GL031951 Geophysical Research Letters 34 Department of Geology and Geophysics, University of Wisconsin-Madison, 1215 W. Dayton Street, Madison, WI 53706, United States; Department of Earth Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, United States; Department of Earth and Environment Sciences, Rensselaer Polytechnic Institute, Troy, NY 12180, United States 24 Anisotropy; Compressive stress; Mathematical models; Microcracks; Shear waves; Three dimensional; Tomography; Velocity, Shear wave splitting delay; Shear-wave splitting tomography; Spatial anisotropy distribution, Seismic waves, anisotropy; fault zone; imaging method; microcrack; polarization; ray tracing; S-wave; San Andreas Fault; seismic tomography; spatial variation; wave splitting, California; North America; Parkfield; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-39549117811&doi=10.1029%2f2007GL031951&partnerID=40&md5=cd3a14bb37b5ffe0e27a4e8bc93e4d3c cited By 39 H. Zhang Y. Liu C. Thurber S. Roecker article Deutsch2007635 The 1.07 Myr old Lake Bosumtwi impact crater in Ghana was drilled within the framework of the International Continental Scientific Drilling Project (ICDP). Hole LB-08A, drilled into the outer flank of the central uplift and with a total depth of 451 m, yielded 215.71 m of impact-related rocks. This paper summarizes observations of the lithological logging on core LB-08A. Between a depth of 235.6 and ∼260 m, the section consists of a melt-bearing allochthonous, polymict, and mostly clast-supported impact breccia. Down to ∼418 m, the section comprises a rather uniform unit of meta-graywacke alternating with phyllite to slate (lower greenschist facies); few (par-) autochthonous impact breccia bodies and rare impact dike breccias are present. The lowermost part of the section contains several centimeter- to decimeter-thick melt-bearing breccia dikes in country rocks identical to those occurring above. Omnipresent fracturing was mapped in a qualitative manner. Most prominent shock effects in the uplifted target rocks comprise planar fractures and deformation elements in quartz and polysynthetic twinning in carbonate minerals; the maximum shock pressure as evidenced by quartz is below 26 GPa. The allochthonous breccias occasionally contain a few vol% of melt particles. Suevites occur outside the crater rim, carrying diaplectic crystals, coesite, and ballen quartz as well as true melt glasses and a variety of lithic clasts, among those spectacular staurolite-rich mica-schists. The recorded shock level in the uplifted target rocks is lower than expected and modeled. Shock recovery experiments with analogue carbonaceous graywackes at 34 and 39.5 GPa yielded nearly complete transformation of quartz into diaplectic glass. We therefore exclude a specific shock behavior of the soft, fluid-rich target material (carbonaceous graywackes, shales, slates) in core LB-08A as the prime or only reason for the melt deficit and the generally low shock levels recorded inside the Lake Bosumtwi impact crater. © The Meteoritical Society, 2007. Printed in USA. Article 2007 English 10869379 10.1111/j.1945-5100.2007.tb01065.x Meteoritics and Planetary Science 42 University of Arkansas 635 – 654 4-5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-34250644945&doi=10.1111%2fj.1945-5100.2007.tb01065.x&partnerID=40&md5=011f7e936f22c35c6bac6fe3423e6a6c Cited by: 24; All Open Access, Bronze Open Access Alexander Deutsch Sabine Luetke Volker Heinrich article Boamah2007561 Lake Bosumtwi is a natural inland freshwater lake that originated from a meteorite impact. The lake is becoming a popular tourist attraction in Ghana and has the potential to be developed as an ecotourism site in the future. However, there have been some unregulated human activities and unplanned infrastructure development, and there are increased levels of pollutants in the lake water. In order to make ecotourism at Lake Bosumtwi successful in the long term, the Lake Bosumtwi Development Committee has been formed to ensure that local people are empowered to mobilize their own capacities. It has been realized that an important criterion required to develop ecotourism in a socially responsible, economically efficient, and environmentally viable way is to foster a constructive dialogue between the local people and tourists about the needs of the indigenous people. © The Meteoritical Society, 2007. Printed in USA. Article 2007 English 10869379 10.1111/j.1945-5100.2007.tb01061.x Meteoritics and Planetary Science 42 University of Arkansas 561 – 567 4-5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-34250625648&doi=10.1111%2fj.1945-5100.2007.tb01061.x&partnerID=40&md5=9d6b9ca02224c27939e39c1e6644c108 Cited by: 17 Daniel Boamah Christian Koeberl article Ugalde2007793 The Bosumtwi impact structure in Ghana is the youngest and best-preserved medium-sized impact structure on Earth, and because of the vast amount of prior geophysical and geological data gathered in the area, it constitutes a great natural laboratory to try to develop new geophysical interpretation and modeling techniques. During the 2004 International Continental Scientific Drilling Program (ICDP) drilling campaign at Lake Bosumtwi, we made magnetic field observations at 162 stations around the lake. This study differs from all previous magnetic surveys at Bosumtwi, which only measured the scalar portion of the Earth's magnetic field, in that we measured the full magnetic vector at each station. Acquisition of the full magnetic vector was made possible by innovative use of a borehole deviation probe, which uses a magnetic sensor for absolute orientation reference. Estimates of the magnetic vector orientation and magnitude at each observation station were derived from a series of measurements collected at 50 cm spacing over a depth range of 25 m. In this study, we report a comparison between the scalar total field intensity derived from this new survey approach with the other two previously acquired marine and airborne magnetic data sets. The scalar total magnetic intensity (TMI) computed from the vector data set compares in close agreement with the other two data sets. Some discrepancies between the data sets can be explained by differences in the distances between the sensor and the magnetic sources for the various surveys. The highlight of this study is that we demonstrate that is possible to acquire at least partial vector data with readily available instrumentation. © The Meteoritical Society, 2007. Printed in USA. Article 2007 English 10869379 10.1111/j.1945-5100.2007.tb01075.x Meteoritics and Planetary Science 42 University of Arkansas 793 – 800 4-5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-34250629233&doi=10.1111%2fj.1945-5100.2007.tb01075.x&partnerID=40&md5=8c0735e38c0622933d51dfc8b1b357ef Cited by: 5 Hernan Ugalde William A. Morris Christina Clark Brett Miles Bernd Milkereit article Ugalde2007867 The Bosumtwi impact structure (Ghana) is a young and well-preserved structure where a vast amount of information is available to constrain any geophysical model. Previous analysis of the airborne magnetic data and results of numerical simulation of impact predicted a strongly magnetic impact-melt body underneath the lake. Recent drilling through the structure did not penetrate such an expected impact-melt rock magnetic source. A new 3-D magnetic model for the structure was constructed based on a newly acquired higher-resolution marine magnetic data set, with consideration of the observed gravity data on the lake, previous seismic models, and the magnetic properties and lithology identified in the two International Continental Scientific Drilling Program (ICDP) deep boreholes. The new model contains highly magnetic bodies located in the northeast sector of the structure, not centered onto the drilling sites. As in previous models, higher magnetization than that measured in outcropping impactites had to be assigned to the unexposed source bodies. Integration of the new model with the borehole petrophysics and published geology indicates that these bodies likely correspond to an extension to the south of the Kumasi batholith, which outcrops to the northeast of the structure. The possibility that these source bodies are related to the seismically identified central uplift or to an unmapped impact-melt sheet predicted by previous models of the structure is not supported. Detailed magnetic scanning of the Kumasi batholith to the north, and the Bansu intrusion to the south, would provide a test for this interpretation. © The Meteoritical Society, 2007. Printed in USA. Article 2007 English 10869379 10.1111/j.1945-5100.2007.tb01082.x Meteoritics and Planetary Science 42 University of Arkansas 867 – 882 4-5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-34250650095&doi=10.1111%2fj.1945-5100.2007.tb01082.x&partnerID=40&md5=7db204d1ebffd5cd39a09b98524a018b Cited by: 13; All Open Access, Bronze Open Access Hernan Ugalde William A. Morris Lauri J. Pesonen Sylvester K. Danuor article Lozhkin2007135 Three types of pollen assemblages (shrub-dominated, mixed herb- and shrub-dominated, and herb-dominated) characterize the ∼300,000 year palynological record from El'gygytgyn Lake. Despite major changes in global climatic forcings, all pollen spectra, with a few isolated exceptions, have strong to possible analogs in the modern plant communities of Northeast Siberia and Alaska. Paleoclimatic reconstructions based on squared chord-distance analog analyses indicate two periods (∼8600-10,700 14C year B.P. and OIS 5e) when summers were perhaps ∼2 to 4°C warmer than modern. January temperatures were also warmer than present, and both July and January were wetter than today. Palynological data remain inconclusive as to the establishment of forests near El'gygytgyn Lake at these times. The wettest Julys occurred during OIS 5 d. July temperatures were near modern, and Januarys were colder and drier than now. January temperatures, even into the Middle Pleistocene, generally show little variability, suggesting that the suppression of arboreal taxa during glaciations was likely caused by cool summers with low effective moisture and not by frigid winters. Because age schemes that correlate magnetic susceptibility to variations in summer insolation or ∂18O have cool plant taxa persisting in warm times (and vice versa), we propose an alternative age model based on the palynological data. © 2006 Springer Science+Business Media B.V. 2007 English 09212728 10.1007/s10933-006-9018-5 Journal of Paleolimnology 37 135-153 North East Interdisciplinary Research Institute, Russian Academy of Sciences, 16 Portovaya St., Magadan 685000, Russian Federation; Earth and Space Sciences and Quaternary Research Center, University of Washington, P. Box 351310, Seattle, WA 98195-1310, United States 1 paleoclimate; paleoecology; palynology; Pleistocene; pollen; vegetation history, Chukchi; Eurasia; Lake El'gygytgyn; Russian Federation https://www.scopus.com/inward/record.uri?eid=2-s2.0-33845957928&doi=10.1007%2fs10933-006-9018-5&partnerID=40&md5=7eea56448300ee5da2130d0059127cfe cited By 108 A.V. Lozhkin P.M. Anderson T.V. Matrosova P.S. Minyuk book Elders2007337 The vast scale of drilling worldwide for economic goals dwarfs the number of scientific drilling projects. This alone creates a strong incentive for the ICDP to collaborate with industry. Given the current world energy situation, the growing amount of drilling for unconventional energy resources is increasing opportunities for such collaboration. Two examples are discussed here, the Mallik Gas Hydrate Production Research Program, and the ongoing Iceland Deep Drilling Project. The Mallik project was collaboration between industry and government agencies that investigated gas hydrates in permafrost in Arctic Canada. Gas hydrates are a new, and potentially large, source of energy. Past periods of rapid atmospheric warming in the geologic record may have been initiated, or significantly accelerated, by dissociation of such gas hydrates. The Iceland Deep Drilling Project is another collaboration between industry and government, but it is investigating unconventional geothermal resources in Iceland. This project will drill a series of 4 to 5 km deep wells in the search for supercritical hydrothermal fluids at temperatures of 450-500 °C. It is estimated that power output from wells producing supercritical fluid will be an order of magnitude greater than produced from conventional geothermal wells. Supercritical fluids play a fundamental role in coupling magmatic and hydrothermal systems on mid-ocean ridges. In the future, many other important scientific questions could be addressed by the ICDP participating in similar natural resource drilling projects. © 2007 Springer-Verlag Berlin Heidelberg. 2007 English 9783540687771 10.1007/978-3-540-68778-8_9 Continental Scientific Drilling: A Decade of Progress, and Challenges for the Future Springer Berlin Heidelberg 337-366 Department of Earth Sciences, University of California, Riverside, CA 92521, United States; Geological Survey of Canada, Sidney, BC V8L 5S, Canada https://www.scopus.com/inward/record.uri?eid=2-s2.0-78649896195&doi=10.1007%2f978-3-540-68778-8_9&partnerID=40&md5=90e01c4d2c5ff5f9b0c69f56e2b8a9ac cited By 3 W.A. Elders S.R. Dallimore article Liu2007454 The 5158 m deep main hole of the Chinese Continental Scientific Drilling Project (CCSD-MH) at Maobei, southwestern Sulu Belt, penetrated five major lithologic units: eclogite, amphibolite ± retrograde eclogite, ultramafic rock, paragneiss, and orthogneiss. All analyzed samples are overprinted to various extents by amphibolite-facies retrograde metamorphism. Ultrahigh-pressure (UHP) index minerals are preserved as inclusions in zircons separated from 137 core samples. These index assemblages include: Coe + Phe + Grt from Grt-Ep-Bt paragneiss; Coe + Jd + Grt + Ap, Coe + Jd + Phe + Ap and Coe + Grt + Jd + Phe from Grt-Ep-Hbl paragneiss; Coe + Phe, Coe + Ky + Ap, and Coe + Ky + Ttn from orthogneiss; and Coe + Grt + Omp, Coe + Grt + Phe, Coe + Omp + Rt, and Coe + Grt + Omp + Phe from Bt-Ep amphibolite and other retrograde eclogites. The common occurrences of these UHP assemblages throughout the section indicate that the drill hole did not penetrate through the UHP tectonic slice. All of the UHP mineral assemblages, whether from retrograde ecologites or from the surrounding gneisses, record similar metamorphic conditions of 773-843°C and 3.2-4.0 GPa. Zircons separated from surface samples and cores from other shallow holes in the area also contain similar coesite-bearing UHP mineral inclusions. This widespread occurrence of UHP assemblages in the southwestern Sulu area suggests that voluminous continental materials were subducted and metamorphosed at mantle depths > 100 km, and then were rapidly exhumed to crustal levels. Copyright © 2007 by V. H. Winston & Son, Inc. All rights reserved. Article 2007 English 00206814 10.2747/0020-6814.49.5.454 International Geology Review 49 454 – 478 5 Asia; China; Eurasia; Far East; Sulu Belt; amphibolite facies; crustal structure; eclogite; exhumation; fluid inclusion; Ocean Drilling Program; orthogneiss; retrograde metamorphism; subduction; ultrahigh pressure metamorphism; ultramafic rock; zircon https://www.scopus.com/inward/record.uri?eid=2-s2.0-34249790856&doi=10.2747%2f0020-6814.49.5.454&partnerID=40&md5=446624ba9dab354ade272f8fcacfb68d Cited by: 51 Fulai Liu Zhiqin Xu J.G. Liou Hailiang Dong Huaimin Xue article Cornet200735 Article 2007 English 18163459 10.2204/iodp.sd.s01.20.2007 Scientific Drilling 35 – 38 1 SUPPL. 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-50649085149&doi=10.2204%2fiodp.sd.s01.20.2007&partnerID=40&md5=1d2fd87318e57247d705ffdc0bab2228 Cited by: 4; All Open Access, Gold Open Access, Green Open Access François Henri Cornet article Plomerová2007675 We present the first results of a high-resolution teleseismic traveltime tomography and seismic anisotropy study of the lithosphere-asthenosphere system beneath the western Bohemian Massif. The initial high-resolution tomography down to a depth of 250 km did not image any columnar low-velocity anomaly which could be interpreted as a mantle plume anticipated beneath the Eger Rift, similar to recent findings of small plumes beneath the French Massif Central and the Eifel in Germany. Alternatively, we interpret the broad low-velocity anomaly beneath the Eger Rift by an upwelling of the lithosphere-asthenosphere transition. We also map lateral variations of seismic anisotropy of the mantle lithosphere from spatial variations of P-wave delay times and the shear wave splitting. Three major domains characterised by different orientations of seismic anisotropy correspond to the major tectonic units - Saxothuringian, Moldanubian and the Teplá-Barrandian - and their fabrics fit to those found in our previous studies of mantle anisotropy on large European scales. © 2007 The Authors Journal compilation © 2007 RAS. Article 2007 English 1365246X 10.1111/j.1365-246X.2007.03361.x Geophysical Journal International 169 675 – 682 2 Bohemian Massif; Central Europe; Eurasia; Europe; asthenosphere; lithosphere; P-wave; rift zone; seismic anisotropy; seismic tomography; teleseismic wave; travel time; upper mantle https://www.scopus.com/inward/record.uri?eid=2-s2.0-34247251535&doi=10.1111%2fj.1365-246X.2007.03361.x&partnerID=40&md5=20f7392f25b4a6bbdfc24c9de5dee735 Cited by: 73; All Open Access, Bronze Open Access Jaroslava Plomerova Ulrich Achauer Vladislav Babuška Ludečk Vecsey article Koeberl2007709 In 2004, an International Continental Scientific Drilling Program (ICDP) drilling project at the Bosumtwi impact crater, Ghana (10.5 km in diameter, 1.07 Myr old), was performed to study the sediments that fill the lake as well as the underlying impactites. In one (LB-05) of 16 cores drilled into the lake sediments, the zone between the impact breccias and the post-impact sediments was penetrated, preserving the final, fine-grained impact fallback layer. This ∼30 cm thick layer contains in the top 10 cm. "accretionary" lapilli, microtektite-like glass spherules, and shocked quartz grains. Glass particles - mostly of splash form less than 1 mm size - make up the bulk of the grains (∼70-78% by number) in the coarser size fraction (> 125 μm) of the top of the fallback layer. About one-third of all quartz grains in the uppermost part of the layer are shocked, with planar deformation features (PDFs); almost half of these grains are highly shocked, with 3 or more sets of PDFs. K-feldspar grains also occur and some show shock deformation. The abundance of shocked quartz grains and the average shock level as indicated by the number of sets of PDFs, for both quartz and K-feldspar, decrease with depth into the layer. The well-preserved glass spherules and fragments are chemically rather homogeneous within each particle, and also show relatively small variations between the various particles. On average, the composition of the fallback spherules from core LB-5B is very similar to the composition of Ivory Coast tektites and microtektites, with the exception of CaO contents, which are about 1.5 to 2 times higher in the fallback spherules. This is a rare case in which the uppermost fallback layer and the transition to the post-impact sediments has been preserved in an impact structure; its presence indicates that the impactite sequence at Bosumtwi is complete and that Bosumtwi is a very well-preserved impact crater. © The Meteoritical Society, 2007. Printed in USA. Article 2007 English 10869379 10.1111/j.1945-5100.2007.tb01069.x Meteoritics and Planetary Science 42 University of Arkansas 709 – 729 4-5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-34250612628&doi=10.1111%2fj.1945-5100.2007.tb01069.x&partnerID=40&md5=eca85547e63cf8f8277c8d7ee64c7d78 Cited by: 48 Christian Koeberl Franz Brandstätter Billy P. Glass Lutz Hecht Dieter Mader Wolf Uwe Reimold article Morrow2007 A technique is presented for estimating frictional strength of narrow shear zones based on hand selection of drillhole cuttings separates. Tests were conducted on cuttings from the SAFOD scientific drillhole near Parkfield, California. Since cuttings are mixed with adjacent material as they travel up the drillhole, these fault-derived separates give a better representation of the frictional properties of narrow features than measurements from the bulk material alone. Cuttings from two shear zones (one an active trace of the San Andreas fault) contain a significant weight percent of clay-rich grains that exhibit deformation-induced slickensides. In addition, cuttings from the active SAF trace contain around 1% serpentine. Coefficients of friction for clay-rich and serpentine grains were 0.3-0.5 and 0.4-0.45, respectively. These values are around 0.12 lower than the friction coefficient of the corresponding bulk cuttings, providing an improved estimate of the frictional strength of the San Andreas fault. Copyright 2007 by the American Geophysical Union. 2007 English 00948276 10.1029/2007GL029665 Geophysical Research Letters 34 U.S. Geological Survey, 345 Middlefield Road, Menlo Park, CA 94025, United States; State University of New York at Stony Brook, Stony Brook, NY 11794, United States; San Houston State University, Huntsville, TX 77340, United States 11 Drilling; Friction; Shear strength, Friction coefficient; Frictional strength; Shear zone, Tectonics, deformation; estimation method; San Andreas Fault; serpentine; shear zone; strength, California; North America; Parkfield; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-34547972644&doi=10.1029%2f2007GL029665&partnerID=40&md5=47dcbe8f1a215c19b5d28ba5b9e4f68d cited By 30 C. Morrow J. Solum S. Tembe D. Lockner T.-F. Wong article Cheng200855 Article 2007 Oil Drilling & Production Technology 5 117-118 8-12 Q. Sun H. Shen X. Yang F. Yuan article https://doi.org/10.1111/j.1755-6724.2007.tb00945.x Abstract: Eclogite lenses in marbles from the Dabie-Sulu ultrahigh-pressure (UHP) terrane are deeply subducted meta-sedimentary rocks. Zircons in these rocks have been used to constrain the ages of prograde and UHP metamorphism during subduction, and later retrograde metamorphism during exhumation. Inherited (detrital) and metamorphic zircons were distinguished on the basis of transmitted light microscopy, cathodoluminescence (CL) imaging, trace element contents and mineral inclusions. The distribution of mineral inclusions combined with CL imaging of the metamorphic zircon make it possible to relate zircon zones (domains) to different metamorphic stages. Domain 1 consists of rounded, oblong and spindly cores with dark-luminescent images, and contains quartz eclogite facies mineral inclusion assemblages, indicating formation under high-pressure (HP) metamorphic conditions of T = 571–668°C and P = 1.7-2.02 GPa. Domain 2 always surrounds domain 1 or occurs as rounded and spindly cores with white-luminescent images. It contains coesite eclogite facies mineral inclusion assemblages, indicating formation under UHP metamorphic conditions of T = 782–849°C and P > 5.5 GPa. Domain 3, with gray-luminescent images, always surrounds domain 2 and occurs as the outermost zircon rim. It is characterized by low-pressure mineral inclusion assemblages, which are related to regional amphibolite facies retrograde metamorphism of T = 600–710°C and P = 0.7-1.2 GPa. The three metamorphic zircon domains have distinct ages; sample H1 from the Dabie terrane yielded SHRIMP ages of 245 ± 4 Ma for domain 1, 235 ± 3 Ma for domain 2 and 215 ± 6 Ma for domain 3, whereas sample H2 from the Sulu terrane yielded similar ages of 244 ± 4 Ma, 233 ± 4 Ma and 214 ± 5 Ma for Domains 1, 2 and 3, respectively. The mean ages of these zones suggest that subduction to UHP depths took place over 10–11 Ma and exhumation of the rocks occurred over a period of 19–20 Ma. Thus, subduction from ∼ 55 km to > 160 km deep mantle depth took place at rates of approximately 9.5–10.5 km/Ma and exhumation from depths >160 km to the base of the crust at −30 km occurred at approximately 6.5 km/Ma. We propose a model for these rocks involving deep subduction of continental margin Iithosphere followed by ultrafast exhumation driven by buoyancy forces after break-off of the UHP slab deep within the mantle. 2007 https://doi.org/10.1111/j.1755-6724.2007.tb00945.x Acta Geologica Sinica - English Edition 81 204-225 2 zoned zircon, SHRIMP U-Pb dating, ultra-deep subduction, fast exhumation, eclogite, lenses in marble, Dabie-Sulu UHP belt https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1755-6724.2007.tb00945.x LIU Fulai A. Gerdes P. T. ROBINSON XUE Huaimin YE Jianguo article Kramar2007824 Synchrotron radiation, collimated to a μm scale was used for the determination of trace elements in micro-tektites and spherule material for the first time. The experimental set-up of the SXRF microprobe at beamline L at HASYLAB at DESY offers a suitable method for performing non-destructive in situ multi-element analysis focusing on spatial trace element distributions and mineral phases of the melted ejecta material from the Cretaceous/Tertiary boundary. The spatial distribution of trace elements was determined in melt inclusions as well as in phase transitions in selected parts of chlorite-smectite spherules and tektite glass material by using a beam with a diameter of 15 μm collimated with a glass capillary for line- and area scans as well as for single point measurements for elements with Z between 19 and 92. The analyzed spherules show alteration features but also zonation and carbonate inclusions, originating from the Chicxulub impact event. These initial results demonstrate the potential of μ-SXRF analysis for the discrimination of alteration and primary signals of the spherules and re-construction of their genetic evolution. It could be shown that the spherules represent a complex mixture of different materials from the subsurface at the Chicxulub impact site. © 2007 Elsevier B.V. All rights reserved. 2007 10.1016/j.sab.2007.06.012 Spectrochimica Acta - Part B Atomic Spectroscopy 62 824-835 Universität Karlsruhe (TH), Institut für Mineralogie und Geochemie, Kaiserstraße 12, D-76128 Karlsruhe, Germany; Utrecht University, Department of Earthsciences, Budapestlaan 4, 3508 TA Utrecht, Netherlands; Hamburger Synchrotronstrahlungslabor HASYLAB at Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, 22607 Hamburg, Germany; GeoForschungsZentrum Potsdam, Division 4.1, Telegrafenberg, 14473 Potsdam, Germany 8 https://www.scopus.com/inward/record.uri?eid=2-s2.0-34547951153&doi=10.1016%2fj.sab.2007.06.012&partnerID=40&md5=2d65eff9a3d50638cf40f7e394f84f94 cited By 3 U. Kramar M. Harting K. Rickers D. Stüben article https://doi.org/10.1111/j.1755-6724.2007.tb01022.x Abstract: The Songliao basin (SB) is a superposed basin with two different kinds of basin fills. The lower one is characterized by a fault-bounded volcanogenic succession comprising of intercalated volcanic, pyroclastic and epiclastic rocks. The volcanic rocks, dating from 110 Ma to 130 Ma, are of geochemically active continental margin type. Fast northward migration of the SB block occurred during the major episodes of the volcanism inferred from their paleomagnetic information. The upper one of the basin fill is dominated by non-marine sag-style sedimentary sequence of siliciclastics and minor carbonates. The basin center shifted westwards from the early to late Cretaceous revealed by the GGT seismic velocity structure suggesting dynamic change in the basin evolution. Thus, a superposed basin model is proposed. Evolution of the SB involves three periods including (1) Alptian and pre-Aptian: a retroarc basin and range system of Andes type related to Mongolia-Okhotsk collisional belt (MOCB); (2) Albian to Companian: a sag-like strike-slip basin under transtension related to oblique subduction of the Pacific plate along the eastern margin of the Eurasian plate; (3) since Maastrichtian: a tectonic inverse basin under compression related to normal subduction of the Pacific plate under the Eurasian plate, characterized by overthrust, westward migration of the depocenter and eastward uplifting of the basin margin. 2007 https://doi.org/10.1111/j.1755-6724.2007.tb01022.x Acta Geologica Sinica - English Edition 81 1002-1011 6 Cretaceous superposed Songliao basin, volcanic rocks, sedimentary sequence, tectonic evolution, Mongolia-Okhotsk collisional belt, Pacific and Eurasian plates, retroarc strike-slip tectonic-inverse basins https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1755-6724.2007.tb01022.x WANG Pujun XIE Xiao'an Mattern FRANK REN Yanguang ZHU Defeng SUN Xiaomeng article sd5702007 2007 10.2204/iodp.sd.5.13.2007 Scientific Drilling 5 70-72 https://sd.copernicus.org/articles/5/70/2007/ Y. Iryu H. Matsuda H. Machiyama W. E. Piller T. M. Quinn M. Mutti article Niessen200749 The 12 km wide and about 175 m deep El'gygytgyn crater lake in Central Chukotka, NE Siberia, is of special interest for investigation as it could provide the first undisturbed 3.6 Ma terrestrial record from the Arctic realm, reaching back a million years before the first major glaciation of the Northern Hemisphere. A single-channel seismic survey was carried out on an expedition to the lake in 2000, in which both high resolution and deep penetration data were acquired. Seismic data suggest an impact crater structure in Cretaceous volcanic bedrock, indicated by velocities of &gt;5000 m s-1, whose upper 500-600 m is brecciated. The lake is filled with two units of sediments, the upper one well stratified and the lower one massive. In the center of the lake, the combined thickness of the two sedimentary units is estimated to be 320-350 m. The upper unit is draped over the location of an interpreted central peak and is locally intercalated with debris flows, mainly in the western part of the lake and at the lake margins. Most of the lower unit is obscured by multiples as a result of high reflection coefficients in the upper unit. As at least the upper unit appears to be undisturbed by glaciation, the lake should yields unique information on the paleoclimatic development of the East Siberian Arctic. © 2006 Springer Science+Business Media B.V. 2007 English 09212728 10.1007/s10933-006-9022-9 Journal of Paleolimnology 37 49-63 Alfred-Wegener-Institute for Polar and Marine Research, Columbusstraße, D-27515 Bremerhaven, Germany; Alfred-Wegener-Institute for Polar and Marine Research, Telegrafenberg A43, D-14473 Potsdam, Germany; University Leipzig, Institute for Geophysics and Geology, Talstr. 35, D-04103 Leipzig, Germany 1 crater lake; impact structure; lacustrine deposit; paleoclimate; seismic data; seismic survey, Chukchi; Eurasia; Lake El'gygytgyn; Russian Federation https://www.scopus.com/inward/record.uri?eid=2-s2.0-33845936633&doi=10.1007%2fs10933-006-9022-9&partnerID=40&md5=cf701803e0b557de48ff2585e86076ec cited By 36 F. Niessen A.C. Gebhardt C. Kopsch B. Wagner article Sulem20073 Within the frame of the 'CRL' (Corinth Rift Laboratory project) [Cornet, F., Bernard, P., Moretti, I., (2004a): The Corinth Rift Laboratory, Comptes Rendus Geosciences, 336, 4-5, 235-242.] centered on the south western sector of the Gulf of Corinth (http://www.corinth-rift-lab.org), fault zone cores from the active Aigion Fault have been collected continuously from depths between 708 and 782 m. Inside this clayey core, a clear shearing surface with marked slip lines is visible on a plane that makes a 68° angle with respect to the core axis. This failure surface was not induced by the decompression process but is indeed a slip plane as clear striation is observed at the interface. On the basis of an elasto-plastic constitutive model calibrated on triaxial tests on the clayey gouge, it is shown that shear band formation inside the clayey core is possible. The solution for the orientation of the shear band is compared to the orientation of an existing slip surface inside the clayey gouge and this result is used to deduce the orientation of the principal stresses. It is shown that as commonly observed in weak fault zones, the orientation of the principal stresses is locally almost parallel and perpendicular to the fault axis. © 2007 Elsevier B.V. All rights reserved. Article 2007 English 00401951 10.1016/j.tecto.2007.03.005 Tectonophysics 442 3 – 13 1-4 Gulf of Corinth; Ionian Sea; Mediterranean Sea; active fault; constitutive equation; elastoplasticity; fault zone; shear band; strain analysis; stress analysis; triaxial test https://www.scopus.com/inward/record.uri?eid=2-s2.0-34548307245&doi=10.1016%2fj.tecto.2007.03.005&partnerID=40&md5=755e46565fc3dc2c1cacb34e1d42ecae Cited by: 14; All Open Access, Green Open Access Jean Sulem article Bräuer2007 We present a study considering the systematics of gas and isotope compositions (3He/4He, δ13 CCO2, δ13 CCH4, δ 15N) of a permanent magmatic CO2 flux in the hydrothermal system of the spring "Wettinquelle" in Bad Brambach and their relation to the seismic activity beneath the western Eger rift. The gas and isotope compositions were monitored for more than 3 years. The time series includes periods before, during, and after a 4-month-long seismically active period from the end of August to the end of December 2000. Shifts due to admixture of crustal components were found for all monitored isotope ratios during and after the seismically active period. In case of helium and nitrogen, isotopic anomalies occurred already about 6 weeks before the beginning of the seismically active period, contemporaneous with a water level anomaly of the well VL4 near the Wettinquelle. On the one hand, preseismic deformations may be responsible for the observed isotope anomalies; on the other hand, coseismic fracturing processes in the surroundings of the hypocenters may play a role. Both effects produce greater permeability and result in the release of crustal fluids. The migration and admixture of these crustal components to the "permanent" upper mantle-derived fluid flux result in geochemical anomalies that persist for more than 2 years. The results of the detailed isotope monitoring have proven to be an important contribution to understand the geodynamic processes that may presently be going on in the region Vogtland/NW Bohemia. Copyright 2007 by the American Geophysical Union. Article 2007 English 21699313 10.1029/2006JB004404 Journal of Geophysical Research: Solid Earth 112 Blackwell Publishing Ltd 4 Central Europe; Eger; Eurasia; Europe; Heves; Hungary; coseismic process; fluid composition; geodynamics; hydrothermal system; isotopic composition; thermal spring https://www.scopus.com/inward/record.uri?eid=2-s2.0-34250690764&doi=10.1029%2f2006JB004404&partnerID=40&md5=8eeb69f543fa0a54bc5845db364fbdeb Cited by: 33 Karin Bräuer Horst Kämpf Ulrich Koch Samuel Niedermann Gerhard Strauch article Ellsworth200784 2007 English 18168957 10.2204/iodp.sd.s01.04.2007 Scientific Drilling 84-87 U.S. Geological Survey (USGS), 3A-109, 345 Middlefield Road Mail Stop 977, Menlo Park, Calif. 94025, United States; Old Chemistry, Duke University, Box 90227, Durham, N.C. 27708, United States; Geological Survey of Japan, Institute of Geology and Geoinformation (AIST), Tsukuba Central 7, 1-1-1 Higashi, Japan; Department of Earth and Environmental Sciences, Rensselaer Polytechnic Institute, Science Center 1S06, Troy, N.Y. 12180, United States; Berkeley Seismological Lab, University of California Berkeley, 207 McCone Hall, Calif. 94720-4760, United States; Norwegian Seismic Array (NORSAR), P.O. Box 53, N-2027 Kjeller, Norway; Department of Geology and Geophysics, University of Wisconsin, 1215 West Dayton Street, Madison, Wis. 53706, United States; LDEO-Seismology Geology and Tectonophysics, 210 Seismology, 61 Route 9W - P.O. Box 1000, Palisades, N.Y. 10964, United States; Energy Technology Centers (ETC), San Ramon, Calif. 94583, United States; USGS, 345 Middlefield Road, Menlo Park, Calif. 94025, United States; Department of Geophysics, Stanford University, Mitchell Bldg., Stanford, Calif. 94305, United States 1 SUPPL. 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-72049098074&doi=10.2204%2fiodp.sd.s01.04.2007&partnerID=40&md5=9a2477b3c6dc316811d75fa8f600f1ad cited By 13 W.L. Ellsworth K. Imanishi R. Nadeau V. Oye F. Waldhauser N.L. Boness S.H. Hickman M.D. Zoback article Ellsworth200784 2007 English 18168957 10.2204/iodp.sd.s01.04.2007 Scientific Drilling 84-87 U.S. Geological Survey (USGS), 3A-109, 345 Middlefield Road Mail Stop 977, Menlo Park, Calif. 94025, United States; Old Chemistry, Duke University, Box 90227, Durham, N.C. 27708, United States; Geological Survey of Japan, Institute of Geology and Geoinformation (AIST), Tsukuba Central 7, 1-1-1 Higashi, Japan; Department of Earth and Environmental Sciences, Rensselaer Polytechnic Institute, Science Center 1S06, Troy, N.Y. 12180, United States; Berkeley Seismological Lab, University of California Berkeley, 207 McCone Hall, Calif. 94720-4760, United States; Norwegian Seismic Array (NORSAR), P.O. Box 53, N-2027 Kjeller, Norway; Department of Geology and Geophysics, University of Wisconsin, 1215 West Dayton Street, Madison, Wis. 53706, United States; LDEO-Seismology Geology and Tectonophysics, 210 Seismology, 61 Route 9W - P.O. Box 1000, Palisades, N.Y. 10964, United States; Energy Technology Centers (ETC), San Ramon, Calif. 94583, United States; USGS, 345 Middlefield Road, Menlo Park, Calif. 94025, United States; Department of Geophysics, Stanford University, Mitchell Bldg., Stanford, Calif. 94305, United States 1 SUPPL. 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-72049098074&doi=10.2204%2fiodp.sd.s01.04.2007&partnerID=40&md5=9a2477b3c6dc316811d75fa8f600f1ad cited By 13 W.L. Ellsworth K. Imanishi R. Nadeau V. Oye F. Waldhauser N.L. Boness S.H. Hickman M.D. Zoback article Morrow2007591 Standard and universal stage optical microscope and microRaman spectroscopic examination of quartz from the upper impactite interval of the International Continental Scientific Drilling Program (ICDP) Lake Bosumtwi crater drill core LB-07A demonstrates widespread but heterogeneous evidence of shock metamorphism. In the upper impactite, which comprises interbedded polymict lithic breccia and suevite from a drilling depth of 333.4-415.7 m, quartz occurs as a major component within metasedimentary lithic clasts and as abundant, isolated, single-crystal grains within matrix. The noted quartz shock-metamorphic features include phenomena related to a) deformation, such as abundant planar microstructures, grain mosaicism, and reduced birefringence; b) phase transformations, such as rare diaplectic quartz glass and very rare coesite; c) melting, such as isolated, colorless to dark, glassy and devitrified vesicular melt grains; and d) secondary, post-shock features such as abundant, variable decoration of planar microstructures and patchy grain toasting. Common to abundant planar deformation features (PDFs) in quartz are dominated by ω {1013}-equivalent crystallographic planes, although significant percentages of π{1012} and other higher index orientations also occur; notably, c(0001) planes are rare. Significantly, the quartz PDF orientations match most closely those reported elsewhere from strongly shocked, crystalline-target impactites. Barometry estimates based on quartz alteration in the upper impactite indicate that shock pressures in excess of 20 GPa were widely reached; pressures exceeding 40-45 GPa were more rare. The relatively high abundances of decorated planar microstructures and grain toasting in shocked quartz, together with the nature and distribution of melt within suevite, suggest a water- or volatile-rich target for the Bosumtwi impact event. © The Meteoritical Society, 2007. Printed in USA. Article 2007 English 10869379 10.1111/j.1945-5100.2007.tb01063.x Meteoritics and Planetary Science 42 University of Arkansas 591 – 609 4-5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-34250642323&doi=10.1111%2fj.1945-5100.2007.tb01063.x&partnerID=40&md5=84376da44430d0bdc080c4f4168e0319 Cited by: 17; All Open Access, Bronze Open Access Jared R. Morrow article Shanahan20071678 Historical changes in the level of Lake Bosumtwi, Ghana, have been simulated using a catchment-scale hydrological model in order to assess the importance of changes in climate and land use on lake water balance on a monthly basis for the period 1939-2004. Several commonly used models for computing evaporation in data-sparse regions are compared, including the Penman, the energy budget, and the Priestley - Taylor methods. Based on a comparison with recorded lake level variations, the model with the energy-budget evaporation model subcomponent is most effective at reproducing observed lake level variations using regional climate records. A sensitivity analysis using this model indicates that Lake Bosumtwi is highly sensitive to changes in precipitation, cloudiness and temperature. However, the model is also sensitive to changes in runoff related to vegetation, and this factor needs to be considered in simulating lake level variations. Both interannual and longer-term changes in lake level over the last 65 years appear to have been caused primarily by changes in precipitation, though the model also suggests that the drop in lake level over the last few decades has been moderated by changes in cloudiness and temperature over that time. Based on its effectiveness at simulating the magnitude and rate of lake level response to changing climate over the historical record, this model offers a potential future opportunity to examine the palaeoclimatic factors causing past lake level fluctuations preserved in the geological record at Lake Bosumtwi. Copyright © 2006 John Wiley & Sons, Ltd. Article 2007 English 10991085 10.1002/hyp.6359 Hydrological Processes 21 1678 – 1691 13 Africa; Ashanti; Ghana; Lake Bosumtwi; Sub-Saharan Africa; West Africa; Atmospheric temperature; Catchments; Climate change; Computer simulation; Evaporation; Hydrology; Land use; Mathematical models; Precipitation (meteorology); Sensitivity analysis; Atmospheric temperature; Catchments; Climate change; Computer simulation; Evaporation; Land use; Mathematical models; Precipitation (meteorology); Sensitivity analysis; catchment; climate change; energy budget; hydrological modeling; lake level; lake water; land use; water budget; Catchment-scale hydrological model; Energy-budget evaporation model; Hydrology https://www.scopus.com/inward/record.uri?eid=2-s2.0-34447094371&doi=10.1002%2fhyp.6359&partnerID=40&md5=4c0a2923874a66bed668d24179c6c973 Cited by: 54 Timothy M. Shanahan Jonathan T. Overpeck W.E. Sharp Christopher A. Scholz Justice A. Arko article Garcia2007 The Hawai'i Scientific Drilling Project (HSDP2) successfully drilled ∼3.1 km into the island of Hawai'i. Drilling started on Mauna Loa volcano, drilling 247mof subaerial lavas before encountering 832m of subaerial Mauna Kea lavas, followed by 2019 m of submarine Mauna Kea volcanic and sedimentary units. The 2.85 km stratigraphic record of Mauna Kea volcano spans back to ∼650 ka. Mauna Kea subaerial lavas have high average olivine contents (13 vol.%) and low average vesicle abundances (10 vol.%). Most subaerial Mauna Kea flows are 'a'ā (∼63%), whereas the Mauna Loa section contains nearly equal amounts of pāhoehoe and 'a'ā (like its current surface). The submarine Mauna Kea section contains an upper, ∼900 m thick, hyaloclastite-rich section and a lower, ∼1100 m thick, pillow-lavadominated section. These results support a model that Hawaiian volcanoes are built on a pedestal of pillow lavas capped by rapidly quenched, fragmented lava debris. The HSDP2 section is compared here to a 1.7 km deep hole (SOH1) on Kilauea's lower east rift zone. Differences in the sections reflect the proximity to source vents and the lower magma supply to Kilauea's rift zone. Both drill core sections are cut by intrusions, but the higher abundance of intrusions in SOH1 reflects its location within a rift zone, causing more extensive alteration in the SOH1 core. The HSDP2 site recovered a relatively unaltered core well suited for geochemical analyses of the single deepest and most complete borehole ever drilled through a Hawaiian or any other oceanic island volcano. Copyright 2007 by the American Geophysical Union. Article 2007 English 15252027 10.1029/2006GC001379 Geochemistry, Geophysics, Geosystems 8 2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-58849162832&doi=10.1029%2f2006GC001379&partnerID=40&md5=7877eb9ce27e29e3ec6ac7daacbc4dc4 Cited by: 59; All Open Access, Green Open Access Michael O. Garcia Eric H. Haskins Edward M. Stolper Michael Baker article Wu2007 The Taiwan Chelungpu-fault Drilling Project (TCDP) drilled a 2-km-deep research borehole to investigate the structure and mechanics of the Chelungpu Fault that ruptured in the 1999 Mw 7.6 Chi-Chi earthquake. Geophysical logs of the TCDP were carried out over depths of 500-1900 in, including Dipole Sonic Imager (DSI) logs and Formation Micro Imager (FMI) logs in order to identify bedding planes, fractures and shear zones. From the continuous core obtained from the borehole, a shear zone at a depth of 1110 meters is interpreted to be the Chelungpu fault, located within the Chinshui Shale, which extends from 1013 to 1300 meters depth. Stress-induced borehole breakouts were observed over nearly the entire length of the wellbore. These data show an overall stress direction (∼N115°E) that is essentially parallel to the regional stress field and parallel to the convergence direction of the Philippine Sea plate with respect to the Eurasian plate. Variability in the average stress direction is seen at various depths. In particular there is a major stress orientation anomaly in the vicinity of the Chelungpu fault. Abrupt stress rotations at depths of 1000 in and 1310 in are close to the Chinshui Shale's upper and lower boundaries, suggesting the possibility that bedding plane slip occurred during the Chi-Chi earthquake. Copyright 2007 by the American Geophysical Union. 2007 English 00948276 10.1029/2006GL028050 Geophysical Research Letters 34 Institute of Geophysics, National Central University, 300 Jhongda Road, Chung-Li 32001, Taiwan; Department of Geophysics, Stanford University, Stanford, CA 94305, United States; Japan Agency for Marine-Earth Science and Technology, 2-9 Nishi-Shinbashi 1-chome, Minato-ku, Tokyo 105-0003, Japan; U.S. Geological Survey, 345 Middlefield Road, Menlo Park, CA 94025, United States 1 Boreholes; Earthquakes; Image sensors; Mechanics; Structural geology; Tectonics, Dipole Sonic Imager (DSI); Formation Micro Imager (FMI); Geophysical logs, Geophysical prospecting, bedding plane; borehole; Chi-Chi earthquake 1999; earthquake rupture; Eurasian plate; Philippine Sea plate; shear zone; stress field; well logging, Asia; Eurasia; Far East; Taiwan https://www.scopus.com/inward/record.uri?eid=2-s2.0-34548007902&doi=10.1029%2f2006GL028050&partnerID=40&md5=fc41a04af36a0475f6b888f2d1f3587f cited By 82 H.-Y. Wu K.-F. Ma M. Zoback N. Boness H. Ito J.-H. Hung S. Hickman article Kring20074 An impact-mass extinction hypothesis for the Cretaceous-Tertiary (K/T) boundary transition has been confirmed with multiple lines of evidence, beginning with the discovery of impact-derived Ir in K/T boundary sediments and culminating in the discovery of the Chicxulub impact crater. Likewise, a link between the Chicxulub impact crater and K/T boundary sediments has been confirmed with multiple lines of evidence, including stratigraphic, petrological, geochemical, and isotopic data. The environmental effects of the Chicxulub impact event were global in their extent, largely because of the interaction of ejected impact debris with the atmosphere. The environmental consequences of the Chicxulub impact event and their association with the K/T boundary mass extinction event indicate that impact cratering processes can affect both the geologic and biologic evolution of our planet. © 2007 Elsevier B.V. All rights reserved. 2007 10.1016/j.palaeo.2007.02.037 Palaeogeography, Palaeoclimatology, Palaeoecology 255 4-21 Lunar and Planetary Laboratory, Department of Geosciences, The University of Arizona, Tucson, AZ 85721, United States 1-2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-34948856485&doi=10.1016%2fj.palaeo.2007.02.037&partnerID=40&md5=637be1308034a8f641227ac4a9f9ee0a cited By 161 D.A. Kring article Scholz2007549 The Lake Bosumtwi impact structure in West Africa offers unparalleled opportunities for the study cratering processes, as the structure is young (1.1 Myr) and minimally eroded. Because the center part of the structure is covered by Lake Bosumtwi, which is 8 km in diameter and ∼70 m deep, it is possible to use marine-type seismic reflection techniques to obtain high-fidelity images of the lake subsurface, including key elements of the impact structure. Eight profiles of multichannel seismic reflection (MCS) data were acquired in a radial pattern across the basin, as well as two other high-resolution seismic reflection surveys. The MCS data show a well-defined central uplift near the north-central part of the lake. Observed within the annular moat surrounding the buried central uplift is a section of post-impact lacustrine sediments more than 300 m thick. The central uplift structure has a diameter of 1.9 km and a maximum height of 130 m above the annular moat. The central uplift has an overall irregular upper surface with a small graben structure. We observe a series of normal faults that extend as much as 120 m into the sedimentary section above the central uplift. We interpret the normal faults to be a consequence of ongoing compaction of the high-porosity materials that comprise the central uplift. The interpreted impact structure surface, defined using seismic reflection data, was combined with regional topographic data from outside the lake in the form of a digital elevation model, which provides a useful perspective of overall impact structure morphology. © The Meteoritical Society, 2007. Printed in USA. Article 2007 English 10869379 10.1111/j.1945-5100.2007.tb01060.x Meteoritics and Planetary Science 42 University of Arkansas 549 – 560 4-5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-34250629649&doi=10.1111%2fj.1945-5100.2007.tb01060.x&partnerID=40&md5=fad922c8c746c98f69241617070f1cbf Cited by: 14; All Open Access, Bronze Open Access Christopher A. Scholz Tobias Karp Robert P. Lyons article Hickman200729 2007 English 18168957 10.2204/iodp.sd.s01.39.2007 Scientific Drilling 29-32 U.S. GeologicalSurvey, 345 Middlefield Road, Mail Stop 977, Menlo Park, Calif., 94025, United States; Stanford University, Mitchell Building, Stanford, Calif., 94305-2215, United States; Chevron Energy Technology Company, 6001 Bollinger Canyon Road, San Ramon, Calif., 94583, United States; Duke University, 109A Old Chem, Box 90227, Durham, N.C., 27708, United States; Department of Earth and Environmental Sciences, Rensselaer Polytechnic Institute, Troy, N.Y., 12180, United States; Department of Geology and Geophysics, University of Wisconsin, 1215 West Dayton Street, Madison, Wis., 53706, United States 1 SUPPL. 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-51449106268&doi=10.2204%2fiodp.sd.s01.39.2007&partnerID=40&md5=6b9e15e33208e84fa895397387ed61e6 cited By 31 S. Hickman M. Zoback W. Ellsworth N. Boness P. Malin S. Roecker C. Thurber article Hung200755 2007 English 18168957 10.2204/iodp.sd.s01.27.2007 Scientific Drilling 55-58 Department of Earth Sciences and Institute of Geophysics, National Central University, No. 300, Jhongda Road, Johngli City, Taoyuan County, 32001, Taiwan; Department of Earth Sciences and Institute of Geophysics, National Central University, No. 300, Jhongda Road, Johngli City, Taoyuan County, 32001, Taiwan; Department of Geosciences, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei, 10617, Taiwan; Center for Deep Earth Exploration (CDEX), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 3173-25 Showa-machi, Kanazawa-ku, Yokohama, Kanagawa 236-0001, Japan; Kochi Institute for Core Sample Research, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), B200 Monobe, Nankoku, Kochi, 783-8502, Japan 1 SUPPL. 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-78651537907&doi=10.2204%2fiodp.sd.s01.27.2007&partnerID=40&md5=cf701d4721308fc9bf5ed142f7be4a5d cited By 2 J.-H. Hung K.-F. Ma C.-Y. Wang S.-R. Song H. Ito W. Lin E.-C. Yeh conference Berner200761 The study investigates the geochemistry of sulfur in the sequence of volcanic rocks recovered by a 3098m deep drilling executed on the flank of the Mauna Kea volcano. Though mineralogic investigations indicate the presence of sulfur bearing minerals which may have crystallized directly from the plume melt, contents and isotopic composition of sulfur suggest that the original composition of the melt was altered due to degassing and interaction with seawater derived fluids. © 2007 Taylor & Francis Group, London. Conference paper 2007 English 978-041545135-2 Water-Rock Interaction - Proceedings of the 12th International Symposium on Water-Rock Interaction, WRI-12 1 61 – 64 Degassing; Geochemistry; Offshore oil wells; Sulfur; Volcanic rocks; Weathering; Deep drilling; Isotopic composition; Seawater https://www.scopus.com/inward/record.uri?eid=2-s2.0-84858020648&partnerID=40&md5=be691d87fcf45e70a69f4ffae02bea13 Cited by: 0 Z. Berner G. Istrate D. Stüben article heim2007supplementary5 2007 GFZ Data Services Birgit Heim J Klump Hedi Oberhänsli N Fagel article Moore2007795 The section of the San Andreas fault located between Cholame Valley and San Juan Bautista in central California creeps at a rate as high as 28 mm yr -1 (ref. 1), and it is also the segment that yields the best evidence for being a weak fault embedded in a strong crust. Serpentinized ultramafic rocks have been associated with creeping faults in central and northern California, and serpentinite is commonly invoked as the cause of the creep and the low strength of this section of the San Andreas fault. However, the frictional strengths of serpentine minerals are too high to satisfy the limitations on fault strength, and these minerals also have the potential for unstable slip under some conditions. Here we report the discovery of talc in cuttings of serpentinite collected from the probable active trace of the San Andreas fault that was intersected during drilling of the San Andreas Fault Observatory at Depth (SAFOD) main hole in 2005. We infer that the talc is forming as a result of the reaction of serpentine minerals with silica-saturated hydrothermal fluids that migrate up the fault zone, and the talc commonly occurs in sheared serpentinite. This discovery is significant, as the frictional strength of talc at elevated temperatures is sufficiently low to meet the constraints on the shear strength of the fault, and its inherently stable sliding behaviour is consistent with fault creep. Talc may therefore provide the connection between serpentinite and creep in the San Andreas fault, if shear at depth can become localized along a talc-rich principal-slip surface within serpentinite entrained in the fault zone. ©2007 Nature Publishing Group. 2007 English 00280836 10.1038/nature06064 Nature 448 Nature Publishing Group 795-797 US Geological Survey, Mail Stop 977, 345 Middlefield Road, Menlo Park, CA 94025, United States 7155 mineral; serpentine; talc, creep; fault slip; fault zone; hydrothermal fluid; San Andreas Fault; serpentinite; shear strength; sliding; talc; ultramafic rock, article; chemical reaction; friction; gravity; priority journal; rock; temperature, California; Cholame Valley; North America; San Juan Bautista; San Luis Obispo County; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-34547957163&doi=10.1038%2fnature06064&partnerID=40&md5=767bc8f06bee7c3c3f410fd0cf989c1c cited By 325 D.E. Moore M.J. Rymer article DeNatale200748 Conference paper 2007 English 18163459 10.2204/iodp.sd.4.15.2007 Scientific Drilling 48 – 50 4 https://www.scopus.com/inward/record.uri?eid=2-s2.0-78651563043&doi=10.2204%2fiodp.sd.4.15.2007&partnerID=40&md5=5b6e15e7ecd821c9efaff1c021efb48d Cited by: 3; All Open Access, Gold Open Access, Green Open Access Giuseppe De Natale Claudia Troise Marco Sacchii article Hirono2007 The Taiwan Chelungpu-Fault Drilling Project was undertaken in 2002 to investigate the faulting mechanism of the 1999 Mw 7.6 Taiwan Chi-Chi earthquake. Hole B penetrated the Chelungpu fault, and core samples were recovered from between 948.42- and 1352.60-m depth. Three major zones, designated FZB1136 (fault zone at 1136-m depth in hole B), FZB1194, and FZB1243, were recognized in the core samples as active fault zones within the Chelungpu fault. Nondestructive continuous physical property measurements, conducted on all core samples, revealed that the three major fault zones were characterized by low gamma ray attenuation (GRA) densities and high magnetic susceptibilities. Extensive fracturing and cracks within the fault zones and/or loss of atoms with high atomic number, but not a measurement artifact, might have caused the low GRA densities, whereas the high magnetic susceptibility values might have resulted from the formation of magnetic minerals from paramagnetic minerals by frictional heating. Minor fault zones were characterized by low GRA densities and no change in magnetic susceptibility, and the latter may indicate that these minor zones experienced relatively low frictional heating. Magnetic susceptibility in a fault zone may be key to the determination that frictional heating occurred during an earthquake on the fault. Copyright 2007 by the American Geophysical Union. 2007 English 21699313 10.1029/2006JB004738 Journal of Geophysical Research: Solid Earth 112 Blackwell Publishing Ltd Department of Earth and Space Science, Graduate School of Science, Osaka University, Toyonaka 560-0043 Osaka, Japan; Kochi Institute for Core Sample Research, Japan Agency for Marine Earth Science and Technology, Nankoku, Kochi, Japan; Department of Geosciences, National Taiwan University, Taipei, Taiwan; Department of Geophysics, School of Earth Sciences, Stanford University, Stanford, CA, United States; Center for Advanced Marine Core Research, Kochi University, Nankoku, Kochi, Japan; Department of Natural Environmental Science, Faculty of Science, Kochi University, Kochi, Japan; Institute for Geo-Resources and Environment, National Institute of Advanced Industrial Science and Technology, Tsukuba, Japan; Center for Deep Earth Exploration, Japan Agency for Marine-Earth Science and Technology, Yokohama, Japan; Institute for Research on Earth Evolution, Japan Agency for Marine Earth Science and Technology, Yokosuka, Japan; Institute of Geophysics, National Central University, Jhongli, Taiwan; Marine Works Japan Ltd., Yokohama, Japan 7 active fault; Chi-Chi earthquake 1999; fault zone; faulting; magnetic susceptibility, Asia; Eurasia; Far East; Taiwan https://www.scopus.com/inward/record.uri?eid=2-s2.0-34548522847&doi=10.1029%2f2006JB004738&partnerID=40&md5=739cc0d49cf2d2f767a9aac8c6da03a4 cited By 42 T. Hirono E.-C. Yeh W. Lin H. Sone T. Mishima W. Soh Y. Hashimoto O. Matsubayashi K. Aoike H. Ito M. Kinoshita M. Murayama S.-R. Song K.-F. Ma J.-H. Hung C.-Y. Wang Y.-B. Tsai T. Kondo M. Nishimura S. Moriya T. Tanaka T. Fujiki L. Maeda H. Muraki T. Kuramoto K. Sugiyama T. Sugawara article Bleibinhaus2007 A seismic reflection and refraction survey across the San Andreas Fault (SAF) near Parkfield provides a detailed characterization of crustal structure across the location of the San Andreas Fault Observatory at Depth (SAFOD). Steep-dip prestack migration and frequency domain acoustic waveform tomography were applied to obtain highly resolved images of the upper 5 km of the crust for 15 km on either side of the SAF. The resulting velocity model constrains the top of the Salinian granite with great detail. Steep-dip reflection seismic images show several strong-amplitude vertical reflectors in the uppermost crust near SAFOD that define an ∼2-km-wide zone comprising the main SAF and two or more local faults. Another prominent subvertical reflector at 2-4 km depth ∼9 km to the northeast of the SAF marks the boundary between the Franciscan terrane and the Great Valley Sequence. A deep seismic section of low resolution shows several reflectors in the Salinian crust west of the SAF. Two horizontal reflectors around 10 km depth correlate with strains of seismicity observed along-strike of the SAF. They represent midcrustal shear zones partially decoupling the ductile lower crust from the brittle upper crust. The deepest reflections from ∼25 km depth are interpreted as crust-mantle boundary. Copyright 2007 by the American Geophysical Union. 2007 English 21699313 10.1029/2006JB004611 Journal of Geophysical Research: Solid Earth 112 Blackwell Publishing Ltd Department of Geosciences, Virginia Tech., 4044 Derring Hall, Blacksburg, VA 24061, United States; GeoForschungsZentrum, Telegrafenberg E322, Potsdam 14471, Germany; U.S. Geological Survey, 345 Middlefield Rd., Menlo Park, CA 94025, United States; Earth Resources Laboratory, Massachusetts Institute of Technology, Cambridge, MA, United States 6 crust-mantle boundary; crustal structure; prestack migration; San Andreas Fault; seismic reflection; seismic refraction; seismic tomography; seismic wave; waveform analysis, California; North America; Parkfield; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-34548380833&doi=10.1029%2f2006JB004611&partnerID=40&md5=dff59c55e1ec756dd8c9e8df12847552 cited By 106 F. Bleibinhaus J.A. Hole T. Ryberg G.S. Fuis conference Oye2007747 In 2005, the San Andreas Fault Observatory at Depth (SAFOD) was drilled through the San Andreas Fault zone at a depth of about 3.1 km. The borehole has subsequently been instrumented with high-frequency geophones in order to better constrain locations and source processes of nearby microearthquakes that will be targeted in the upcoming phase of SAFOD. The microseismic monitoring software MIMO, developed by NORSAR, has been installed at SAFOD to provide near-real time locations and magnitude estimates using the high sampling rate (4000 Hz) waveform data. To improve the detection and location accuracy, we incorporate data from the nearby, shallow borehole (∼250 m) seismometers of the High Resolution Seismic Network (HRSN). The event association algorithm of the MIMO software incorporates HRSN detections provided by the USGS real time earthworm software. The concept of the new event association is based on the generalized beam forming, primarily used in array seismology. The method requires the pre-computation of theoretical travel times in a 3D grid of potential microearthquake locations to the seismometers of the current station network. By minimizing the differences between theoretical and observed detection times an event is associated and the location accuracy is significantly improved. 2007 English 9781605601557 69th European Association of Geoscientists and Engineers Conference and Exhibition 2007: Securing The Future. Incorporating SPE EUROPEC 2007 2 Society of Petroleum Engineers 747-751 NORSAR; USGS Buildings; Exhibitions; Location; MIM devices; Multiplexing; Observatories; Satellite observatories; Seismographs, 3D grids; Beam forming; Detection times; High frequencies; High resolution seismic; Location accuracies; Micro earthquakes; Microseismic monitoring; Real times; Sampling rates; San andreas faults; Shallow boreholes; Source processes; Station networks; Travel times; Waveform datums, Seismology https://www.scopus.com/inward/record.uri?eid=2-s2.0-55549085218&partnerID=40&md5=5fe876f1fa76ed8d08ec5ca3c5b69510 cited By 2 V. Oye W.L. Ellsworth book Koeberl200795 Currently about 170 impact craters are known on Earth; about one third of those structures are not exposed on the surface and can only be studied by geophysics or drilling. The impact origin of geological structures can only be confirmed by petrographic and geochemical studies; thus, it is of crucial importance to obtain samples of subsurface structures. In addition, structures that have surface exposures commonly require drilling and drill cores to obtain information of the subsurface structure, to provide ground-truth for geophysical studies, and to obtain samples of rock types not exposed at the surface. For many years, drilling of impact craters was rarely done in dedicated projects, mainly due to the high cost involved. Structures were most often drilled for reasons unrelated to their impact origin. In the former Soviet Union a number of impact structures were drilled for scientific reasons, but in most of these cases the curation and proper care of the cores was not guaranteed. More recently the International Continental Scientific Drilling Program (ICDP) has supported projects to study impact craters. The first ICDPsupported study of an impact structure was the drilling into the 200-kmdiameter, K-T boundary age, subsurface Chicxulub impact crater, Mexico, which occurred between December 2001 and February 2002. The core retrieved from the borehole Yaxcopoil-1, 60 km SSW from the center of the structure, reached a depth of 1511 m and intersected 100 m of impact melt breccia and suevite, which has been studied by an international team. From June to October 2004, the 10.5 km Bosumtwi crater, Ghana, was drilled within the framework of an ICDP project, to obtain a complete 1 million year paleoenvironmental record in an area for which only limited data exist, and to study the subsurface structure and crater fill of one of the best preserved large, young impact structures. From September to December 2005, the main part of another ICDP-funded drilling project was conducted, at the 85-km-diameter Chesapeake Bay impact structure, eastern USA, which involved drilling to a depth of 1.8 km. In 2008, it is likely that the El'ygytgyn structure (Arctic Russia) will be drilled as well. So far only few craters have been drilled - not enough to gain a broad understanding of impact crater formation processes and consequences. In this chapter we summarize the current status of scientific drilling at impact craters, and provide some guidance and suggestions about future drilling projects that are relevant for impact research. Points we cover include: what is the importance of studying impact craters and processes, why is it important to drill impact craters or impact crater lakes, which important questions can be answered by drilling, which craters would be good targets and why; is there anything about the impact process, or of impact relevance, that can be learned by drilling outside any craters; what goals should be set for the future; how important is collaboration between different scientific fields? In the following report, we first briefly discuss the importance of impact cratering, then summarize experience from past drilling projects (ICDP and others), and finally we try to look into the future of scientific drilling of impact structures. © 2007 Springer-Verlag Berlin Heidelberg. 2007 English 9783540687771 10.1007/978-3-540-68778-8_3 Continental Scientific Drilling: A Decade of Progress, and Challenges for the Future Springer Berlin Heidelberg 95-161 Department of Geological Sciences, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria; Department of Physics, University of Toronto, 60 St. George Street, Toronto, ON M5S 1A7, Canada https://www.scopus.com/inward/record.uri?eid=2-s2.0-62849087451&doi=10.1007%2f978-3-540-68778-8_3&partnerID=40&md5=9355d072f6daf494807ad2d6383dc4f9 cited By 11 C. Koeberl B. Milkereit article Morris2007769 An impact event always creates a cloud of ejecta generated through excavation of the target. Subsequent in-filling of the void by crater-fill deposits provides a record of post-impact processes. Full-core digital photographic scans of core segments from borehole LB-07 in the Bosumtwi impact crater provide a complete record of the in-fill process. The shape, orientation, and size of clasts within the impact breccia were measured using a best-fit ellipsoid approach. Clast size and variance, together with clast orientation data, suggest the impact breccias at Bosumtwi can be divided into a simple two-fold subdivision that loosely agrees with the lithological zonation of a lower monomict breccia overlain by a polymict breccia. The lower unit is characterized by a uniform and finer-grained clast size together with a uniform flat-lying clast orientation. The boundary between the two zones is defined by a sharp increase in clast size. The upper zone shows an average increase in clast size with decreasing depth, but full grain size spectrum together with increased grain size deviation suggest that this is a result of mixing between two populations with different grain size distribution. The main population of clasts shows an incremental decrease of clast size with decreasing depth. The upper zone also contains weakly defined shallowly dipping clast fabrics, which may be suggestive of horizontal transport or deposition onto an inclined surface. © The Meteoritical Society, 2007. Printed in USA. Article 2007 English 10869379 10.1111/j.1945-5100.2007.tb01073.x Meteoritics and Planetary Science 42 University of Arkansas 769 – 778 4-5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-34250619597&doi=10.1111%2fj.1945-5100.2007.tb01073.x&partnerID=40&md5=586462d9c7133e8b2e8c6c368031ac20 Cited by: 5; All Open Access, Bronze Open Access William A. Morris Hernan Ugalde Christina Clark Brett Miles article heim2007continent5 2007 GFZ Data Services Birgit Heim J Klump Alexander Schulze Gangolf Dachnowski Hedi Oberhänsli book Koeberl200795 Currently about 170 impact craters are known on Earth; about one third of those structures are not exposed on the surface and can only be studied by geophysics or drilling. The impact origin of geological structures can only be confirmed by petrographic and geochemical studies; thus, it is of crucial importance to obtain samples of subsurface structures. In addition, structures that have surface exposures commonly require drilling and drill cores to obtain information of the subsurface structure, to provide ground-truth for geophysical studies, and to obtain samples of rock types not exposed at the surface. For many years, drilling of impact craters was rarely done in dedicated projects, mainly due to the high cost involved. Structures were most often drilled for reasons unrelated to their impact origin. In the former Soviet Union a number of impact structures were drilled for scientific reasons, but in most of these cases the curation and proper care of the cores was not guaranteed. More recently the International Continental Scientific Drilling Program (ICDP) has supported projects to study impact craters. The first ICDPsupported study of an impact structure was the drilling into the 200-kmdiameter, K-T boundary age, subsurface Chicxulub impact crater, Mexico, which occurred between December 2001 and February 2002. The core retrieved from the borehole Yaxcopoil-1, 60 km SSW from the center of the structure, reached a depth of 1511 m and intersected 100 m of impact melt breccia and suevite, which has been studied by an international team. From June to October 2004, the 10.5 km Bosumtwi crater, Ghana, was drilled within the framework of an ICDP project, to obtain a complete 1 million year paleoenvironmental record in an area for which only limited data exist, and to study the subsurface structure and crater fill of one of the best preserved large, young impact structures. From September to December 2005, the main part of another ICDP-funded drilling project was conducted, at the 85-km-diameter Chesapeake Bay impact structure, eastern USA, which involved drilling to a depth of 1.8 km. In 2008, it is likely that the El'ygytgyn structure (Arctic Russia) will be drilled as well. So far only few craters have been drilled - not enough to gain a broad understanding of impact crater formation processes and consequences. In this chapter we summarize the current status of scientific drilling at impact craters, and provide some guidance and suggestions about future drilling projects that are relevant for impact research. Points we cover include: what is the importance of studying impact craters and processes, why is it important to drill impact craters or impact crater lakes, which important questions can be answered by drilling, which craters would be good targets and why; is there anything about the impact process, or of impact relevance, that can be learned by drilling outside any craters; what goals should be set for the future; how important is collaboration between different scientific fields? In the following report, we first briefly discuss the importance of impact cratering, then summarize experience from past drilling projects (ICDP and others), and finally we try to look into the future of scientific drilling of impact structures. © 2007 Springer-Verlag Berlin Heidelberg. Book chapter 2007 English 978-354068777-1 10.1007/978-3-540-68778-8_3 Continental Scientific Drilling: A Decade of Progress, and Challenges for the Future Springer Berlin Heidelberg 95 – 161 https://www.scopus.com/inward/record.uri?eid=2-s2.0-62849087451&doi=10.1007%2f978-3-540-68778-8_3&partnerID=40&md5=9355d072f6daf494807ad2d6383dc4f9 Cited by: 11; All Open Access, Bronze Open Access Christian Koeberl Bernd Milkereit book Koeberl200795 Currently about 170 impact craters are known on Earth; about one third of those structures are not exposed on the surface and can only be studied by geophysics or drilling. The impact origin of geological structures can only be confirmed by petrographic and geochemical studies; thus, it is of crucial importance to obtain samples of subsurface structures. In addition, structures that have surface exposures commonly require drilling and drill cores to obtain information of the subsurface structure, to provide ground-truth for geophysical studies, and to obtain samples of rock types not exposed at the surface. For many years, drilling of impact craters was rarely done in dedicated projects, mainly due to the high cost involved. Structures were most often drilled for reasons unrelated to their impact origin. In the former Soviet Union a number of impact structures were drilled for scientific reasons, but in most of these cases the curation and proper care of the cores was not guaranteed. More recently the International Continental Scientific Drilling Program (ICDP) has supported projects to study impact craters. The first ICDPsupported study of an impact structure was the drilling into the 200-kmdiameter, K-T boundary age, subsurface Chicxulub impact crater, Mexico, which occurred between December 2001 and February 2002. The core retrieved from the borehole Yaxcopoil-1, 60 km SSW from the center of the structure, reached a depth of 1511 m and intersected 100 m of impact melt breccia and suevite, which has been studied by an international team. From June to October 2004, the 10.5 km Bosumtwi crater, Ghana, was drilled within the framework of an ICDP project, to obtain a complete 1 million year paleoenvironmental record in an area for which only limited data exist, and to study the subsurface structure and crater fill of one of the best preserved large, young impact structures. From September to December 2005, the main part of another ICDP-funded drilling project was conducted, at the 85-km-diameter Chesapeake Bay impact structure, eastern USA, which involved drilling to a depth of 1.8 km. In 2008, it is likely that the El'ygytgyn structure (Arctic Russia) will be drilled as well. So far only few craters have been drilled - not enough to gain a broad understanding of impact crater formation processes and consequences. In this chapter we summarize the current status of scientific drilling at impact craters, and provide some guidance and suggestions about future drilling projects that are relevant for impact research. Points we cover include: what is the importance of studying impact craters and processes, why is it important to drill impact craters or impact crater lakes, which important questions can be answered by drilling, which craters would be good targets and why; is there anything about the impact process, or of impact relevance, that can be learned by drilling outside any craters; what goals should be set for the future; how important is collaboration between different scientific fields? In the following report, we first briefly discuss the importance of impact cratering, then summarize experience from past drilling projects (ICDP and others), and finally we try to look into the future of scientific drilling of impact structures. © 2007 Springer-Verlag Berlin Heidelberg. 2007 English 9783540687771 10.1007/978-3-540-68778-8_3 Continental Scientific Drilling: A Decade of Progress, and Challenges for the Future Springer Berlin Heidelberg 95-161 Department of Geological Sciences, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria; Department of Physics, University of Toronto, 60 St. George Street, Toronto, ON M5S 1A7, Canada https://www.scopus.com/inward/record.uri?eid=2-s2.0-62849087451&doi=10.1007%2f978-3-540-68778-8_3&partnerID=40&md5=9355d072f6daf494807ad2d6383dc4f9 cited By 11 C. Koeberl B. Milkereit book Ivanov2007207 To use the information about impact craters on terrestrial planets for study of planetary geology and geophysics, one should combine a wide set of processes and parameters. The chapter presents a review of impact cratering processes, estimates of average impact velocities, and impact probability for terrestrial planets. Basics of the impact crater scaling is discussed to present to date level of confidence in problems, where one needs to correlate measured size of an impact crater and mass and size of a body, created the impact structure. Scaling laws for large impact crates are discussed in comparison with results of the direct numerical modeling of impact cratering. The accumulation rate for impact craters on terrestrial planets is believed to be constant (within a factor of 2) during the last ∼3 Ga of the solar system history. Measuring the number of accumulated craters of a given size in the area of interest, one can estimate relative age of the visible surface, provided the older surfaces accumulate larger number of craters. In connection with this technique measured size-frequency distribution of impact craters is discussed, including the now widely disputable topic of secondary cratering, preventing the simple interpretation of cratering record for small craters. © 2007 Elsevier B.V. All rights reserved. 2007 10.1016/B978-044452748-6.00158-9 Treatise on Geophysics: Volume 1-10 1-10 207-242 Institute for Dynamics of Geospheres, Moscow, Russian Federation; Planetary Science Institute, Tucson, AZ, United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-85146742339&doi=10.1016%2fB978-044452748-6.00158-9&partnerID=40&md5=ef83e1f3feb20b9c656e1635463e825f cited By 0 B.A. Ivanov W.K. Hartmann book Koeberl200795 Currently about 170 impact craters are known on Earth; about one third of those structures are not exposed on the surface and can only be studied by geophysics or drilling. The impact origin of geological structures can only be confirmed by petrographic and geochemical studies; thus, it is of crucial importance to obtain samples of subsurface structures. In addition, structures that have surface exposures commonly require drilling and drill cores to obtain information of the subsurface structure, to provide ground-truth for geophysical studies, and to obtain samples of rock types not exposed at the surface. For many years, drilling of impact craters was rarely done in dedicated projects, mainly due to the high cost involved. Structures were most often drilled for reasons unrelated to their impact origin. In the former Soviet Union a number of impact structures were drilled for scientific reasons, but in most of these cases the curation and proper care of the cores was not guaranteed. More recently the International Continental Scientific Drilling Program (ICDP) has supported projects to study impact craters. The first ICDPsupported study of an impact structure was the drilling into the 200-kmdiameter, K-T boundary age, subsurface Chicxulub impact crater, Mexico, which occurred between December 2001 and February 2002. The core retrieved from the borehole Yaxcopoil-1, 60 km SSW from the center of the structure, reached a depth of 1511 m and intersected 100 m of impact melt breccia and suevite, which has been studied by an international team. From June to October 2004, the 10.5 km Bosumtwi crater, Ghana, was drilled within the framework of an ICDP project, to obtain a complete 1 million year paleoenvironmental record in an area for which only limited data exist, and to study the subsurface structure and crater fill of one of the best preserved large, young impact structures. From September to December 2005, the main part of another ICDP-funded drilling project was conducted, at the 85-km-diameter Chesapeake Bay impact structure, eastern USA, which involved drilling to a depth of 1.8 km. In 2008, it is likely that the El'ygytgyn structure (Arctic Russia) will be drilled as well. So far only few craters have been drilled - not enough to gain a broad understanding of impact crater formation processes and consequences. In this chapter we summarize the current status of scientific drilling at impact craters, and provide some guidance and suggestions about future drilling projects that are relevant for impact research. Points we cover include: what is the importance of studying impact craters and processes, why is it important to drill impact craters or impact crater lakes, which important questions can be answered by drilling, which craters would be good targets and why; is there anything about the impact process, or of impact relevance, that can be learned by drilling outside any craters; what goals should be set for the future; how important is collaboration between different scientific fields? In the following report, we first briefly discuss the importance of impact cratering, then summarize experience from past drilling projects (ICDP and others), and finally we try to look into the future of scientific drilling of impact structures. © 2007 Springer-Verlag Berlin Heidelberg. 2007 10.1007/978-3-540-68778-8_3 Continental Scientific Drilling: A Decade of Progress, and Challenges for the Future 95-161 Department of Geological Sciences, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria; Department of Physics, University of Toronto, 60 St. George Street, Toronto, ON M5S 1A7, Canada https://www.scopus.com/inward/record.uri?eid=2-s2.0-62849087451&doi=10.1007%2f978-3-540-68778-8_3&partnerID=40&md5=9355d072f6daf494807ad2d6383dc4f9 cited By 11 C. Koeberl B. Milkereit article Lozhkin2007550 The comprehensive study of the upper 1283 cm of sediment from Lake El'gygytgyn, which formed nearly 4 Ma ago following a meteorite impact in northern Chukotka, yielded the first continuous record of the extreme changes in the Beringian climate and vegetation from the middle Middle Pleistocene to recent time (equivalent of marine isotope stages of 1-7 and the upper part of isotope stage 8). During this period, the climate was warmer than at present between 8600 and 10 7000 14C years and during the Late Pleistocene (isotope substage 5e, 116-128 ka ago). In 2003, the German-Russian-USA expedition continued studying sediments of Lake El'gygytgyn to obtain new evidence of the change in the vegetation cover in the Middle Pleistocene and the first information on the Middle Pleistocene interglacial (isotope stage 9; 297-347 ka ago). Pollen spectra characterizing the Middle Pleistocene interglacial are similar to spectra of the early stage of the Early Pleistocene interglacial and the climatic optimum in the Pleistocene to Holocene transitional period. The climatic history of Lake El'gygytgyn is basic for stratigraphic interpretations and correlations in the eastern sector of the Arctic. These data also expand our understanding of climatic changes that are studied within the framework of the "Pole-Equator-Pole Paleoclimate," "Past Global Changes," and other international projects. © Pleiades Publishing, Ltd. 2007. 2007 English 18197140 10.1134/S1819714007060048 Russian Journal of Pacific Geology 1 550-555 Northeast Complex Research Institute, Far East Division, Russian Academy of Sciences, Magadan, Russian Federation; Quaternary Research Center, University of Washington, Seattle, WA, United States; University of Massachusetts, Amherst, MA, United States; Institute of Geophysics and Geology, Leipzig, Germany 6 https://www.scopus.com/inward/record.uri?eid=2-s2.0-37249088882&doi=10.1134%2fS1819714007060048&partnerID=40&md5=d7c8d1184d5e4b44eaa477410728f839 cited By 15 A.V. Lozhkin P.M. Anderson T.V. Matrosova P.S. Minyuk J. Brigham-Grette M. Melles article Keller2007339 Multidisciplinary studies, including stratigraphy, sedimentology, mineralogy and geochemistry, of the new core Mullinax-1 and outcrops along the Brazos River and Cottonmouth Creek, Falls County, Texas, reveal the complex history of the Chicxulub impact, the event deposit and the K-T boundary event. The K-T boundary, as identified by the negative δ13C shift, first occurrence of Danian planktic foraminifera and palynomorphs occurs 80 cm above the event deposit in core Mullinax-1. The underlying 80 cm interval was deposited in a shallow low oxygen environment during the latest Maastrichtian, as indicated by high stress microfossil assemblages, small shells and burrows infilled with framboidal pyrite. The underlying event deposit, commonly interpreted as K-T impact tsunami, consists of a basal conglomerate with clasts containing Chicxulub impact spherules, repeated upward fining units of spherule-rich sands, followed by hummocky cross-bedded and laminated sands, which are burrowed by Thalassinoides, Planolites and Ophiomorpha and truncated by erosion. This suggests a series of temporally separated storm events with re-colonization of the ocean floor by invertebrates between storms, rather than a series of waning tsunami-generated waves. The lithified clasts with impact spherules at the base of the event deposit provide strong evidence that the Chicxulub impact ejecta layer predates the event deposit, but was eroded and re-deposited during the latest Maastrichtian sea level lowstand. The original Chicxulub ejecta layer was discovered in a 3 cm thick yellow clay layer interbedded in undisturbed late Maastrichtian clay- and mudstones 40 cm below the base of the event deposit and near the base of planktic foraminiferal zone CF1, which spans the last 300 kyr of the Maastrichtian. The yellow clay consists of cheto smectite derived from alteration of impact glass, as indicated by rare altered glass spherules with similar chemical compositions as reworked spherules from the event deposit and Chicxulub impact spherules from NE Mexico and Haiti. The Brazos sections thus provide strong evidence that the Chicxulub impact predates the K-T boundary by about 300 kyr, consistent with earlier observations in NE Mexico and the Chicxulub crater core Yaxcopoil-1. © 2007 Elsevier B.V. All rights reserved. 2007 10.1016/j.epsl.2006.12.026 Earth and Planetary Science Letters 255 339-356 Geosciences, Princeton University, Princeton, NJ 08540, United States; Geological Institute, University of Neuchatel, Neuchatel, CH-2007, Switzerland; Institute for Mineralogy and Geochemistry, University of Karlsruhe, 76128 Karlsruhe, Germany; Department of Earth Sciences, Utrecht University, Utrecht, Netherlands; Lewis Energy Group, 10101 Reunion Square, Suite 1000, San Antonio, TX 78216, United States; Free University Berlin, Institute for Geosciences, Section Paleontology, D-12249 Berlin, Germany; Geology Department, South Valley University, Asswan, Egypt 3-4 https://www.scopus.com/inward/record.uri?eid=2-s2.0-33847333344&doi=10.1016%2fj.epsl.2006.12.026&partnerID=40&md5=d1dad90df4dd22a0ac1d942d151f6131 cited By 77 G. Keller T. Adatte Z. Berner M. Harting G. Baum M. Prauss A. Tantawy D. Stueben article Yeh2007327 Taiwan Chelungpu-fault Drilling Project was conducted in drill site Dakeng, Taichung City of central western Taiwan during 2004 - 2005 principally to investigate the rupture mechanism in the northern segment of the Chi-Chi earthquake of 21 September 1999, and also to examine regional stratigraphy and tectonics. Core examination (500 - 1800 m) of Hole-A gave profound results aiding in illustrating the lithologic column, deformation structure, and architectural pattern of fault zones along the borehole. Lithology column of Hole-A was identified downward as the Cholan Formation (500 - 1027 m), Chinshui Shale (1027 - 1268 m), Kueichulin Formation (1268 - 1712 m), and back to the Cholan Formation (1712 - 2003 m) again. A dramatic change is observed regarding sedimentation age and deformation structure around 1712 m. Along the core, most bedding dips 30° toward N105°. Around 1785 m, bedding dip jumps up to 70° until the bottom of borehole. Five structure groups of different orientations (dip direction/dip) are observed throughout the core. Based on the orientation and sense of shear, they are categorized as thrust (105/30), left-lateral fault (015/30 - 80), right-lateral fault (195/30 - 80), normal fault (105/5 - 10), and backthrust (285/40 - 50). Ten fault zones have been recognized between 500 and 2003 m. We interpret the fault zone located at around 1111 m as being the most likely candidate for rupture deformation during Chi-Chi earthquake. The fault zone seated around 1712 m is recognized as the Sanyi fault zone which is 600 m beneath the Chelungpu fault zone. Ten fault zones including thrust faults, strike-slip faults and backthrust are classified as the Chelungpu Fault System (<1250 m) and the Sanyi Fault System (>1500 m). According to the deformation textures within fault zones, the fault zones can be categorized as three types of deformation: distinct fracture deformation, clayey-gouge deformation, and soft-rock deformation. Fracture deformation is dominant within the Chelungpu Fault System and abother two architectures prevail in the Sanyi Fault System. The fracture deformation pattern is asymmetric, which depended the shear sense of fault zone. From the core examination of TCDP Hole-A, the lithology plays an important role in controlling the location and deformation of fault zones. 2007 English 10170839 10.3319/TAO.2007.18.2.327(TCDP) Terrestrial, Atmospheric and Oceanic Sciences 18 327-357 Kochi Institute for Core Sample Research, Japan Agency for Marine-Earth Science and Technology, Kochi, Japan; Department of Geology and Mineralogy, Kyoto University, Kyoto, Japan; Department of Natural Environmental Science, Kochi University, Kochi, Japan; Department of Earth Sciences, Institute of Geophysics, National Central University, Chung-Li, Taiwan; Department of Geosciences, National Taiwan University, Taipei, Taiwan 2 Chi-Chi earthquake 1999; core analysis; deformation mechanism; drilling; fault zone; lithology; normal fault; rupture; tectonic structure, Asia; Eurasia; Far East; Taichung; Taiwan https://www.scopus.com/inward/record.uri?eid=2-s2.0-34547564684&doi=10.3319%2fTAO.2007.18.2.327%28TCDP%29&partnerID=40&md5=805bc91922c2373865b0c64a8e26f672 cited By 56 E.-C. Yeh H. Sone T. Nakaya K.-H. Ian S.-R. Song J.-H. Hung W. Lin T. Hirono C.-Y. Wang K.-F. Ma W. Soh M. Kinoshita article Wu2007295 The results of this nannofossil analysis supply essential information for determining the formation boundaries in the upper Pliocene to Pleistocene. These results also verify the existence of a repetition fossil zone. The TCDP well-A was sunk through the soft fine-grain muddy sandstone and mudstone dominated formations of the Pliocene and Pleistocene in the Taichung area. This study determines methods for providing core preservation in wells at fault zones and establishes a nannofossil biostratigraphy for the integrated Taiwan Chelungpu-fault Drilling Project (TCDP). Good core fabrics are useful for core description and sampling. In this present study, over 400 meters of subsurface cores were covered in resin and slabbed. Digitized images were created for all the core fabrics. More than 150 rock samples were analyzed for nannofossils to give a detailed appraisal of the biostratigraphic column of TCDP well-A. A fossil zone at a depth interval of 431 - 869 m is a NN16 - 18 biozone. This zone is within the Cholan Formation, a lithologic stratigraphy in northern and central Taiwan. The depth interval 883-1226 m is NN15, and is within the Chinshui Shale. The Chelungpu fault is composed of five major shear zones. These are all found at depth within the marine Chinshui Shale. At a depth interval of 1293.37 - 1710 m is a NN12 - 14 biozone; this interval is within the Kueichulin Formation. Interestingly, both the interval beneath 1714 m and the nannofossil zone near the well bottom are NN16 - 18 (Cholan Formation), indicating a repeat of the Cholan Formation. The lowest fossil zone is also abundant in secondary reworked fossils in its assemblages. Hence, the repetition of the younger fossil zone, NN16 - 18, at the bottom of the well verifies the subsurface position of the Sanyi Fault and indicates that TCDP well-A must have passed through it. 2007 English 10170839 10.3319/TAO.2007.18.2.295(TCDP) Terrestrial, Atmospheric and Oceanic Sciences 18 295-325 Exploration and Development Research Institute, Chinese Petroleum Corporation, Miaoli, Taiwan; Department of Earth Sciences, Institute of Geophysics, National Central University, Chung-Li, Taiwan; Department of Earth Science, National Taiwan Normal University, Taipei, Taiwan; Institute of Applied Geophysics, National Taiwan Ocean University, Keelung, Taiwan 2 biostratigraphy; core analysis; lithology; mudstone; nanofossil; Pliocene-Pleistocene boundary; shear zone; slab, Asia; Eurasia; Far East; Taichung; Taiwan https://www.scopus.com/inward/record.uri?eid=2-s2.0-34547562778&doi=10.3319%2fTAO.2007.18.2.295%28TCDP%29&partnerID=40&md5=df6763ad6f5f7615993f9e75c9aa86a9 cited By 6 J.-C. Wu S.-T. Huang M.-H. Wang C.-C. Tsai W.-W. Mei J.-H. Hung T.-Y. Lee K.-M. Yang K.-F. Lee article Brückl2007 Alp01 and Alp02 are the longest profiles recorded during ALP 2002, a large international seismic refraction and wide-angle reflection experiment undertaken in the Eastern Alps in 2002. Alp01 crosses the Alpine orogen from north to south, thus providing a cross section mainly affected by the collision between Europe and the Adriatic microplate. Alp02 extends from the Eastern Alps to the Pannonian basin, supplying evidence on the relation between Alpine crustal structure and tectonic escape to the Pannonian basin. During this experiment, 363 single-channel recorders were deployed along these profiles with an average spacing of 3.2 km. Recordings from 20 inline shots were used in this study. Two-dimensional forward modeling using interactive ray-tracing techniques produced detailed P wave velocity models that contain many features of tectonic significance. Along Alp01, the European Moho dips generally to the south and reaches a maximum depth of 47 km below the transition from the Eastern to the Southern Alps. The Adriatic Moho continues further south at a significantly shallower depth. Moho topography and a prominent south-dipping mantle reflector in the Alpine area support the idea of southward subduction of the European lithosphere below the Adriatic microplate. The most prominent tectonic feature on the Alp02 profile is a vertical step of the Moho at the transition between the Alpine and Pannonian domains, suggesting the existence of a separate Pannonian plate fragment. The development of the Pannonian fragment is interpreted to be a consequence of crustal thinning due to tectonic escape from the Alpine collision area to the Pannonian basin. Copyright 2007 by the American Geophysical Union. Article 2007 English 21699313 10.1029/2006JB004687 Journal of Geophysical Research: Solid Earth 112 Blackwell Publishing Ltd 6 Alps; Eastern Alps; Eurasia; Europe; Pannonian Basin; crustal structure; forward modeling; Moho; ray tracing; seismic reflection; seismic refraction; seismic velocity; seismotectonics https://www.scopus.com/inward/record.uri?eid=2-s2.0-34548448833&doi=10.1029%2f2006JB004687&partnerID=40&md5=ccad174c81a87a00551368f4eb8e5dfa Cited by: 103 Ewald Brückl Florian Bleibinhaus Andrej Gosar Marek Grad Aleksander Guterch Pavla Hrubcová G. Randy Keller Mariusz Majdański Franjo Šumanovac Timo Tiira Jukka Yliniemi Endre Hegedus Hans Thybo article Cherapanova2007155 Diatom species counts were conducted on 171 sediment samples from the 13-m-long core PG1351 from Lake El'gygytgyn, northeast Siberia. The planktonic Cyclotella ocellata-complex dominates the diatom assemblage through most of the core record, persisting through a variety of climate conditions. Periphytic diatoms, although less abundant, have greater diversity and greater down-core assemblage variation. During warm climate modes, longer summer ice-free conditions may have allowed more complex diatom communities to develop in shallow-water habitats, and enhanced circulation may have increased transport of these diatoms to deeper parts of the lake. Zones of low overall diatom abundance further support inferred intervals of low lake productivity during times of extended lake ice and snow cover. More data on the modern spatial and temporal distribution of diatom species in the Lake El'gygytgyn system will improve inferences from core records. © 2006 Springer Science+Business Media B.V. 2007 English 09212728 10.1007/s10933-006-9019-4 Journal of Paleolimnology 37 155-162 Institute of Biology and Soil Science FEB RAS, 159 Prospect 100-Letiya, 690022 Vladivostok, Russian Federation; Department of Geology, Bowling Green State University, 190 Overman Hall, Bowling Green, OH 43403, United States; Department of Geosciences, University of Massachusetts, Morrill Science Building, Amherst, MA 01003, United States 1 climate conditions; core analysis; diatom; paleoclimate; periphyton; plankton; Quaternary; stratigraphy, Chukchi; Eurasia; Lake El'gygytgyn; Russian Federation, Bacillariophyta; Cyclotella ocellata https://www.scopus.com/inward/record.uri?eid=2-s2.0-33845930642&doi=10.1007%2fs10933-006-9019-4&partnerID=40&md5=2be8a6af6d677318b015219294002e1e cited By 39 M.V. Cherapanova J.A. Snyder J. Brigham-Grette article Cheng200855 Article 2007 Petroleum Drilling Techniques 6 22-26 S. Sun L. Yang X. Li X. Wu Z. Wang article Ferrière2007689 The 1.07 Myr old Bosumtwi impact structure in Ghana (West Africa), which measures 10.5 km in diameter and is largely filled by Lake Bosumtwi, is associated with one of four currently known tektite strewn fields. Two boreholes were drilled to acquire hard-rock samples of the deep crater moat and from the flank of the central uplift (LB-07A and LB-08A, respectively) during a recent ICDP-sponsored drilling project. Here we present results of major and trace element analysis of 112 samples from drill core LB-08A. This core, which was recovered between 235.6 and 451.33 m depth below lake level, contains polymict lithic breccia intercalated with suevite, which overlies fractured/brecciated metasediment. The basement is dominated by meta-graywacke (from fine-grained to gritty), but also includes some phyllite and slate, as well as suevite dikelets and a few units of a distinct light greenish gray, medium-grained meta-graywacke. Most of the variations of the major and trace element abundances in the different lithologies result from the initial compositional variations of the various target rock types, as well as from aqueous alteration processes, which have undeniably affected the different rocks. Suevite from core LB-08A (fallback suevite) and fallout suevite samples (from outside the northern crater rim) display some differences in major (mainly in MgO, CaO, and Na2O contents) and minor (mainly Cr and Ni) element abundances that could be related to the higher degree of alteration of fallback suevites, but also result from differences in the clast populations of the two suevite populations. For example, granite clasts are present in fallout suevite but not in fallback breccia, and calcite clasts are present in fallback breccia and not in fallout suevite. Chondrite-normalized rare earth element abundance patterns for polymict impact breccia and basement samples are very similar to each other. Siderophile element contents in the impact breccias are not significantly different from those of the metasediments, or compared to target rocks from outside the crater rim. So far, no evidence for a meteoritic component has been detected in polymict impact breccias during this study, in agreement with previous work. © The Meteoritical Society, 2007. Printed in USA. Article 2007 English 10869379 10.1111/j.1945-5100.2007.tb01068.x Meteoritics and Planetary Science 42 University of Arkansas 689 – 708 4-5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-34250674455&doi=10.1111%2fj.1945-5100.2007.tb01068.x&partnerID=40&md5=4e21c73a5fbedae128a60e706e2415b6 Cited by: 16 Ludovic Ferrière Christian Koeberl Wolf Uwe Reimold Dieter Mader article Ferrière2007611 During a recent drilling project sponsored by the International Continental Scientific Drilling Progam (ICDP), two boreholes (LB-07A and LB-08A) were drilled into the crater fill of the Bosumtwi impact structure and the underlying basement, into the deep crater moat and the outer flank of the central uplift, respectively. The Bosumtwi impact structure in Ghana (West Africa), which is 10.5 km in diameter and 1.07 Myr old, is largely filled by Lake Bosumtwi. Here we present the lithostratigraphy of drill core LB-08A (recovered between 235.6 and 451.33 m depth below lake level) as well as the first mineralogical and petrographic observations of samples from this core. This drill core consists of approximately 25 m of polymict, clast-supported lithic breccia intercalated with suevite, which overlies fractured/brecciated metasediment that displays a large variation in lithology and grain size. The lithologies present in the central uplift are metasediments composed dominantly of fine-grained to gritty meta-graywacke, phyllite, and slate, as well as suevite and polymict lithic impact breccia. The suevites, principally present between 235.6 and 240.5 m and between 257.6 and 262.2 m, display a fine-grained fragmental matrix (about 39 to 45 vol%) and a variety of lithic and mineral clasts that include meta-graywacke, phyllite, slate, quartzite, carbon-rich organic shale, and calcite, as well as melt particles, fractured quartz, unshocked quartz, unshocked feldspar, quartz with planar deformation features (PDFs), diaplectic quartz glass, mica, epidote, sphene, and opaque minerals). The crater-fill suevite contains calcite clasts but no granite clasts, in contrast to suevite from outside the northern crater rim. The presence of melt particles in suevite samples from the uppermost 25 meters of the core and in suevite dikelets in the basement is an indicator of shock pressures exceeding 45 GPa. Quartz grains present in suevite and polymict lithic impact breccia abundantly display 1 to (rarely) 4 sets of PDFs per grain. The shock pressures recorded by the PDFs in quartz grains in the polymict impact breccia range from 10 to ∼30 GPa. We also observed a decrease of the abundance of shocked quartz grains in the brecciated basement with increasing depth. Meta-graywacke samples from the basement are heterogeneously shocked, with shock pressures locally ranging up to 25-30 GPa. Suevites from this borehole show a lower proportion of melt particles and diaplectic quartz glass than suevites from outside the northern crater rim (fallback impact breccia), as well as a lack of ballen quartz, which is present in the external breccias. Similar variations of melt-particle abundance and shock-metamorphic grade between impact-breccia deposits within the crater and fallout impact breccia outside the crater have been observed at the Ries impact structure, Germany. © The Meteoritical Society, 2007. Printed in USA. Article 2007 English 10869379 10.1111/j.1945-5100.2007.tb01064.x Meteoritics and Planetary Science 42 University of Arkansas 611 – 633 4-5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-34250667529&doi=10.1111%2fj.1945-5100.2007.tb01064.x&partnerID=40&md5=d66442439c12c7823abbf9878532c40b Cited by: 36 Ludovic Ferrière Christian Koeberl Wolf Uwe Reimold article Koeberl2007534 Chromium isotopic compositions and elemental abundances in impact melt rock and impact glass samples from four terrestrial impact craters were measured to verify the presence of an extraterrestrial component and to identify the meteorite type of the impactor. All meteorite classes have Cr isotopic signatures that are different from those of terrestrial rocks; thus, precise measurements of Cr isotopic abundances can unequivocally distinguish terrestrial from extraterrestrial materials. For all four studied craters - Bosumtwi (Ghana), Clearwater East (Canada), Lappajärvi (Finland), and Rochechouart (France) we found positive 53Cr excesses that eliminate carbonaceous chondrite projectiles (because those would show apparent negative excesses) and enstatite chondrites (because of the magnitude of the excess). In all four cases, ordinary chondrites have been identified as the best fit for the data; in the case of Lappajärvi interelement correlations together with the Cr isotope data make an H-chondrite the most likely projectile, whereas in the case of Clearwater East both L or H chondrites are possible. For Bosumtwi and Rochechouart the high indigenous contents of the siderophile elements, and disturbances of the elemental abundances by weathering and hydrothermal alteration, respectively, do not allow further constraints to be placed on the type of ordinary chondrite involved in the impact. © 2007 Elsevier B.V. All rights reserved. Article 2007 English 0012821X 10.1016/j.epsl.2007.02.008 Earth and Planetary Science Letters 256 534 – 546 3-4 Africa; Canada; Eurasia; Europe; Finland; France; Ghana; North America; Northern Europe; Scandinavia; Sub-Saharan Africa; West Africa; Western Europe; Chromium; Landforms; Meteorites; Rocks; Stratigraphy; Chondrites; Crater; Meteoritic component; chromium; crater; hydrothermal alteration; isotopic composition; meteorite; weathering; Geochemistry https://www.scopus.com/inward/record.uri?eid=2-s2.0-34047109673&doi=10.1016%2fj.epsl.2007.02.008&partnerID=40&md5=f90628e7bbe93952cb885ce670d9a9ba Cited by: 55 Christian Koeberl Alex Shukolyukov Günter W. Lugmair article Schell2007839 Petrophysical data are commonly used for the discrimination of different lithologies, as the variation in mineralogy, texture, and porosity is accompanied by varying physical properties. A special field of investigation is the analysis of the directional dependence (anisotropy) of the petrophysical properties, which can provide further information on the characteristics of the lithologies, due to the fact that this parameter is different in the various rock-forming and rock-changing processes, e.g., deformation or sedimentation. To characterize the rocks in drill cores LB-07A and LB-08A, which were drilled into the deep crater moat and central uplift of the Bosumtwi impact structure, Ghana, samples were taken for the study of petrophysical properties. In the present work the magnetic properties of these samples were determined in the laboratory. The results are discussed in relation to the various lithologies represented by this sample suite. The shape and degree of magnetic anisotropy, in combination with the magnetic susceptibility, proved useful in distinguishing between the different lithologies present in the drill cores (polymict lithic breccia, suevite, shale component, and meta-graywacke). It was possible to correlate layers of high (shale component), intermediate (graywacke, polymict lithic breccia), and low (suevite) anisotropy degree with the lithostratigraphic sequences determined for cores LB-07A and LB-08A. The shape of the anisotropy showed that foliation is most dominant within the shale component, whereas lineation is more pronounced in the meta-graywacke and polymict lithic breccia. An overall increase of the anisotropy degree was observed from core LB-07A towards core LB-08A. Thus magnetic anisotropy data provide a useful contribution towards an improved petrophysical characterization of the lithostratigraphic sequences in drillcores from the Bosumtwi impact structure. © The Meteoritical Society, 2007. Printed in USA. Article 2007 English 10869379 10.1111/j.1945-5100.2007.tb01079.x Meteoritics and Planetary Science 42 University of Arkansas 839 – 847 4-5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-34250685349&doi=10.1111%2fj.1945-5100.2007.tb01079.x&partnerID=40&md5=0839c7c8f57443ad53c58ee0ae0ef49c Cited by: 3 Christina Schell Norbert Schleifer Tiiu Elbra article Scholz200716416 The environmental backdrop to the evolution and spread of early Homo sapiens in East Africa is known mainly from isolated outcrops and distant marine sediment cores. Here we present results from new scientific drill cores from Lake Malawi, the first long and continuous, high-fidelity records of tropical climate change from the continent itself. Our record shows periods of severe aridity between 135 and 75 thousand years (kyr) ago, when the lake's water volume was reduced by at least 95%. Surprisingly, these intervals of pronounced tropical African aridity in the early late-Pleistocene were much more severe than the Last Glacial Maximum (LGM), the period previously recognized as one of the most arid of the Quaternary. From these cores and from records from Lakes Tanganyika (East Africa) and Bosumtwi (West Africa), we document a major rise in water levels and a shift to more humid conditions over much of tropical Africa after ≈70 kyr ago. This transition to wetter, more stable conditions coincides with diminished orbital eccentricity, and a reduction in precession-dominated climatic extremes. The observed climate mode switch to decreased environmental variability is consistent with terrestrial and marine records from in and around tropical Africa, but our records provide evidence for dramatically wetter conditions after 70 kyr ago. Such climate change may have stimulated the expansion and migrations of early modern human populations. © 2007 by The National Academy of Sciences of the USA. 2007 English 00278424 10.1073/pnas.0703874104 Proceedings of the National Academy of Sciences of the United States of America 104 16416-16421 Department of Earth Sciences, 204 Heroy Geology Laboratory, Syracuse University, Syracuse, NY 13244, United States; Large Lakes Observatory, Department of Geological Sciences, University of Minnesota, Duluth, MN 55812, United States; Department of Geosciences, University of Arizona, Tucson, AZ 85721, United States; Graduate School of Oceanography, University of Rhode Island, Narragansett, RI 02882, United States; Department of Geology and Environmental Science, University of Akron, Akron, OH 44325, United States; Department of Earth Science, University of Bergen, N-5007 Bergen, Norway; Malawi Geological Survey Department, Zomba, Malawi; Geological Survey Department of Ghana, Accra, Ghana; Department of Earth and Environmental Sciences, University of Illinois, Chicago, IL 60607, United States; Scottish Universities Environmental Research Centre, East Kilbride G75 0QF, United Kingdom; Department of Biology, University of Wisconsin-Eau Claire, Eau-Claire, WI 54702, United States 42 Africa; article; climate change; drought; environment; evolution; human; migration; nonhuman; Pleistocene; priority journal, Africa, Eastern; Animals; Evolution; Hominidae; Humans; Natural Disasters; Paleontology; Population; Tropical Climate, Homo sapiens https://www.scopus.com/inward/record.uri?eid=2-s2.0-36749081537&doi=10.1073%2fpnas.0703874104&partnerID=40&md5=f40e36c3f7331068c1f45b8461f35257 cited By 332 C.A. Scholz T.C. Johnson A.S. Cohen J.W. King J.A. Peck J.T. Overpeck M.R. Talbot E.T. Brown L. Kalindekafe P.Y.O. Amoako R.P. Lyons T.M. Shanahan I.S. Castañeda C.W. Heil S.L. Forman L.R. McHargue K.R. Beuning J. Gómez J. Pierson article Bottke200748 The terrestrial and lunar cratering rate is often assumed to have been nearly constant over the past 3 Gyr. Different lines of evidence, however, suggest that the impact flux from kilometre-sized bodies increased by at least a factor of two over the long-term average during the past ∼100 Myr. Here we argue that this apparent surge was triggered by the catastrophic disruption of the parent body of the asteroid Baptistina, which we infer was a ∼170-km-diameter body (carbonaceous-chondrite-like) that broke up Myr ago in the inner main asteroid belt. Fragments produced by the collision were slowly delivered by dynamical processes to orbits where they could strike the terrestrial planets. We find that this asteroid shower is the most likely source (>90 per cent probability) of the Chicxulub impactor that produced the Cretaceous/Tertiary (K/T) mass extinction event 65 Myr ago. ©2007 Nature Publishing Group. 2007 10.1038/nature06070 Nature 449 48-53 Southwest Research Institute, 1050 Walnut St, Boulder, CO 80302, United States; Institute of Astronomy, Charles University, V Holesovickach 2, 18000 Prague 8, Czech Republic 7158 https://www.scopus.com/inward/record.uri?eid=2-s2.0-34548510857&doi=10.1038%2fnature06070&partnerID=40&md5=c8056b1d871dc5fef1d1e5cb54facc69 cited By 142 W.F. Bottke D. Vokrouhlický D. Nesvorný article Bradbury2007299 We examine drill cuttings from the San Andreas Fault Observatory at Depth (SAFOD) boreholes to determine the lithology and deformational textures in the fault zones and host rocks. Cutting samples represent the lithologies from 1.7-km map distance and 3.2-km vertical depth adjacent to the San Andreas Fault. We analyzed two hundred and sixty-six grain-mount thin-sections at an average of 30-m-cuttings sample spacing from the vertical 2.2-km-deep Pilot Hole and the 3.99-km-long Main Hole. We identify Quaternary and Tertiary(?) sedimentary rocks in the upper 700 m of the holes; granitic rocks from 760-1920 m measured depth; arkosic and lithic arenites, interbedded with siltstone sequences, from 1920 to ~3150 m measured depth; and interbedded siltstones, mudstones, and shales from 3150 m to 3987 m measured depth. We also infer the presence of at least five fault zones, which include regions of damage zone and fault core on the basis of percent of cataclasite abundances, presence of deformed grains, and presence of alteration phases at 1050, 1600-2000, 2200-2500, 2700-3000, 3050-3350, and 3500 m measured depth in the Main Hole. These zones are correlated with borehole geophysical signatures that are consistent with the presence of faults. If the deeper zones of cataclasite and alteration intensity connect to the surface trace of the San Andreas Fault, then this fault zone dips 80-85° southwest, and consists of multiple slip surfaces in a damage zone ~250-300 m thick. This interpretation is supported by borehole geophysical studies, which show this area is a region of low seismic velocities, reduced resistivity, and variable porosity. 2007 English 1553040X 10.1130/GES00076.1 Geosphere 3 299-318 Utah State University, Department of Geology, 4505 Old Main Hill, Logan, UT 84322-4505, United States; U.S. Geological Survey, Earthquake Hazards Team, 345 Middlefield Road, MS 977, Menlo Park, CA 94025, United States; Baker Hughes Inteq, 2001 Rankin Road, Houston, TX 77267-0968, United States; Chevron International Exploration and Production, 1500 Louisiana Street, Houston, TX 77002, United States; Shell International Exploration and Production, Inc., Bellaire Technology Center, 3737 Bellaire Blvd, Houston, TX 77025, United States 5 borehole; cutting; deformation mechanism; drilling; fault zone; geophysical method; granite; mineralogy; numerical model; sedimentary rock; seismic velocity; slip; texture, California; San Andreas; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-57849149673&doi=10.1130%2fGES00076.1&partnerID=40&md5=101adf48b66598a4e7034d858b7fe32b cited By 54 K.K. Bradbury D.C. Barton J.G. Solum S.D. Draper J.P. Evans article Wang20071233 Friction is commonly considered an important factor in controlling earthquake rupture. In this work, it is assumed that viscosity is also a significant factor. A strike-slip-type, two-body spring-slider model in the presence of both friction and viscosity is applied to approximate the rupture processes of an earthquake along the fault-striking direction. Results show that in addition to friction, viscosity is also an important factor in controlling rupture. The Ms 7.6 Chi-Chi earthquake which struck central Taiwan on 20 September 1999, ruptured a 100-km-long east-dipping transpressive fault (the Chelungpu fault). Measured and inferred results show that there are differences in physical properties between the northern and southern segments of the fault. Simulation results from a two-body model can explain the differences in displacement, velocity, acceleration, and predominant period between the two fault segments. 2007 English 00371106 10.1785/0120060042 Bulletin of the Seismological Society of America 97 1233-1244 Institute of Earth Sciences, Academia Sinica, P.O. Box 1-55, Nangang, Taipei 115, Taiwan 4 Approximation theory; Computer simulation; Dynamics; Friction; Mathematical models; Physical properties; Viscosity, Earthquake rupture; Fault-striking direction; Transpressive fault, Earthquakes, Chi-Chi earthquake 1999; displacement; earthquake magnitude; earthquake rupture; friction; simulation; strike-slip fault; transpression; viscosity, Asia; Eurasia; Far East; Taiwan https://www.scopus.com/inward/record.uri?eid=2-s2.0-34548078708&doi=10.1785%2f0120060042&partnerID=40&md5=07c25652ebfe05c72dc44e9822764505 cited By 14 J.-H. Wang article Wiersberg2007 We have analyzed noble gas isotopes in 19 mud gas samples from 116-3943 m borehole depth of the San Andreas Fault Observatory at Depth (SAFOD) Main Hole in the context of origin and spatial variability of fluids occurring at seismogenic depths. The measured 3He/4He ratios range between 0.40 and 1.02 Ra (Ra is the atmospheric 3He/4He ratio of 1.39 × 10-6), with 4He/20Ne values between 0.33 and 4.92, revealing a mixture of three components to the total helium: (1) atmospheric helium, (2) helium with a crustal signature, and (3) mantle-derived helium. The air-corrected 3He/4He ratios fall between 0.2 Ra and 0.9 Ra. Samples from the 2117-3196 m depth show a relatively constant helium isotope composition (0.35-0.46 Ra), indicating that ∼5% of the helium in this section the Pacific Plate is derived from the mantle. The contribution of mantle-derived helium increases slightly in the transition from the Pacific Plate to the North American Plate and reaches maximal values of ∼12% on the North American Plate (below ∼3500 m borehole depth). On the basis of our observations, we suggest that the San Andreas Fault plays a role for fluid flux from greater depths, but higher amounts of mantle-derived fluids rise up through other, more permeable faults, situated on the North American Plate of the San Andreas Fault Zone (SAFZ). Lateral fluid dispersion at shallow depths through permeable country rock of the North American Plate may explain the observed increase in 3He/ 4He ratios with increasing distance to the SAF. Copyright 2007 by the American Geophysical Union. 2007 English 15252027 10.1029/2006GC001388 Geochemistry, Geophysics, Geosystems 8 GeoForschungsZentrum Potsdam, Telegrafenberg, D-14473 Potsdam, Germany 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-42349097184&doi=10.1029%2f2006GC001388&partnerID=40&md5=65fd6214b021945c13944c12aba6ed89 cited By 46 T. Wiersberg J. Erzinger article Nowaczyk200765 A combined analysis of magnetic susceptibility, total organic carbon (TOC), biogenic silica (opal), and TiO2 content of the 12.6 m long composite core PG1351 recovered from Lake El'gygytgyn, Chukotka Peninsula, indicate a clear response of the lacustrine sedimentary record to climate variations. The impact is not direct, but through variations in oxygenation of the bottom waters. Mixing of the water body is typical for warmer climates, whereas the development of a stratified water body associated with anoxic conditions at the lake floor appears during cold climates. Oxic conditions lead to a good magnetite preservation and thus to high magnetic susceptibilities, but also to a large-scale degradation of organic matter, as reflected by low TOC (total organic carbon) values. During anoxic conditions, magnetite is severely dissolved yielding very low susceptibility values, whereas organic matter is best preserved, reflected by high TOC values. Hence, in general, neither susceptibility reflects the lithogenic fraction, nor does TOC reflect bioproductivity in case of the studied El'gygytgyn sediments. Based on available infrared stimulated luminescence (IRSL) dating, the obtained susceptibility pattern of core PG1351 shows an obvious correlation to northern hemisphere insolation variations, with a dominating impact of the Earth's 18 and 23 kyr precessional cycles for the upper half of PG1351, that is, during the past 150 ka. Therefore, the whole susceptibility record, together with biogenic silica (as a proxy for bioproductivity), TOC (as an indicator for redox conditions), and TiO2 (as a proxy for lithogenic input), was systematically tuned to the northern hemisphere insolation yielding an age of about 250 ka for the base of the composite core. © 2006 Springer Science+Business Media B.V. 2007 English 09212728 10.1007/s10933-006-9023-8 Journal of Paleolimnology 37 65-76 GeoForschungsZentrum Potsdam, Section 3.3 - Climate Dynamics and Sediments, Telegrafenberg Haus C, D-14474 Potsdam, Germany; Institute for Geophysics and Geology, University Leipzig, Talstrasse 35, D-04103 Leipzig, Germany; North-East Interdisciplinary Science Research Institute (NEISRI), Russian Academy of Sciences, 16 Portovaya St., 685000 Magadan, Russian Federation 1 anoxic conditions; climate variation; core analysis; lacustrine deposit; luminescence dating; magnetic susceptibility; Northern Hemisphere; opal; oxic conditions; total organic carbon, Chukchi; Eurasia; Lake El'gygytgyn; Russian Federation https://www.scopus.com/inward/record.uri?eid=2-s2.0-33845929287&doi=10.1007%2fs10933-006-9023-8&partnerID=40&md5=0012abf9d7eaec777e019246999a9e52 cited By 69 N.R. Nowaczyk M. Melles P. Minyuk article Bulut2007 We relocated part of the aftershock activity in Çιnarcιk Basin and surrounding areas that are associated with the 1999 İzmit earthquake Mw 7.4. Double difference relocation algorithm is used to relocate the aftershocks. The data set was obtained from a temporary seismic network deployed 10 days after the main shock by cooperation between Boǧaziçi University Kandilli Observatory and Earthquake Research Institute, LGIT (Grenoble), and IPGP (Paris). For a better station coverage, additional data set was obtained from a network operated by TUBITAK Marmara Research Center. Differential travel times were calculated using both arrival time readings and waveform cross correlation method. We relocated 1145 of the aftershocks and interpreted the results with emphasis on the Yalova and Tuzla cluster located within the Marmara Sea. The results show better focused seismicity patterns for the Yalova cluster, providing clear evidence for the proposed models. We present a revised location of the 1963 Çιnarcιk earthquake which took place in area of Yalova cluster. Finally we propose that the activity of Tuzla cluster represents a parallel subsidiary fault of the Main Marmara Fault. Copyright 2007 by the American Geophysical Union. 2007 English 00948276 10.1029/2007GL029611 Geophysical Research Letters 34 Department of Geophysics, Kandilli Observatory and Earthquake Research Institute, Boǧaziçi University, Istanbul 34680, Turkey 10 Aftershocks; Double difference method; Double difference relocation algorithm; Seismic network; Seismicity, Algorithms; Correlation methods; Earthquake resistance; Mathematical models; Seismic response; Seismic waves; Waveform analysis, Earthquakes, aftershock; arrival time; Kocaeli earthquake 1999; seismicity; travel time; waveform analysis https://www.scopus.com/inward/record.uri?eid=2-s2.0-34447564097&doi=10.1029%2f2007GL029611&partnerID=40&md5=bb82bb0757548c62036f26407ec902a7 cited By 21 F. Bulut M. Aktar article Lee2007 In contrast to hydrate-free sediments, sonic waveforms acquired in gas hydrate-bearing sediments indicate strong amplitude attenuation associated with a sonic velocity increase. The amplitude attenuation increase has been used to quantify pore-space hydrate content by attributing observed attenuation to the hydrate-bearing sediment's intrinsic attenuation. A second attenuation mechanism must be considered, however. Theoretically, energy radiation from sources inside fluid-filled boreholes strongly depends on the elastic parameters of materials surrounding the borehole. It is therefore plausible to interpret amplitude loss in terms of source coupling to the surrounding medium as well as to intrinsic attenuation. Analyses of sonic waveforms from the Mallik 5L-38 well, Northwest Territories, Canada, indicate a significant component of sonic waveform amplitude loss is due to source coupling. Accordingly, all sonic waveform amplitude analyses should include the effect of source coupling to accurately characterize a formation's intrinsic attenuation. 2007 English 00948276 10.1029/2006GL029015 Geophysical Research Letters 34 U.S. Geological Survey, Denver Federal Center, Box 25046, MS-939, Denver, CO 80225, United States; U.S. Geological Survey, 384 Woods Hole Road, Woods Hole, MA 02543, United States 5 Acoustic wave velocity; Boreholes; Gas hydrates; Sediments; Waveform analysis, Energy radiation; Sonic waveform, Petroleum prospecting, amplitude; pore space; seismic attenuation; sonic boom; wave velocity; waveform analysis, Canada; North America; Northwest Territories https://www.scopus.com/inward/record.uri?eid=2-s2.0-34249904890&doi=10.1029%2f2006GL029015&partnerID=40&md5=8b78445b98da9e52ae77503202c1ca86 cited By 17 M.W. Lee W.F. Waite article Koeberl2007483 The Bosumtwi impact crater in Ghana, arguably the best-preserved complex young impact structure town on Earth, displays a pronounced rim and is almost completely filled by Lake Bosumtwi, a hydrologically closed basin. It is the source crater of the Ivory Coast tektites. The structure was excavated in 2.1-2.2 Gyr old metasediments and metavolcanics of the Birimian Supergroup. A drilling project was conceived that would combine two major scientific interests in this crater: 1) to obtain a complete paleoenvironmental record from the time of crater formation about one million years ago, at a near-equatorial location in Africa for which very few data are available so far, and 2) to obtain a complete record of impactites at the central uplift and in the crater moat, for ground truthing and comparison with other structures. Within the framework of an international and multidisciplinary drilling project led by the International Continental Scientific Drilling Program (ICDP), 16 drill cores were obtained from June to October 2004 at six locations within Lake Bosumtwi, which is 8.5 km in diameter. The 14 sediment cores are currently being investigated for paleoenvironmental indicators. The two impactite cores LB-07A and LB-08A were drilled into the deepest section of the annular moat (540 m) and the flank of the central uplift (450 m), respectively. They are the main subject of this special issue of Meteoritics & Planetary Science, which represents the first detailed presentations of results from the deep drilling into the Bosumtwi impactite sequence. Drilling progressed in both cases through the impact breccia layer into fractured bedrock. LB-07A comprises lithic (in the uppermost part) and suevitic impact breccias with appreciable amounts of impact melt fragments. The lithic clast content is dominated by graywacke, besides various metapelites, quartzite, and a carbonate target component. Shock deformation in the form of quartz grains with planar microdeformations is abundant. First chemical results indicate a number of suevite samples that are strongly enriched in siderophile elements and Mg, but the presence of a definite meteoritic component in these samples cannot be confirmed due to high indigenous values. Core LB-08A comprises suevitic breccia in the uppermost part, followed with depth by a thick sequence of graywacke-dominated metasediment with suevite and a few granitoid dike intercalations. It is assumed that the metasediment package represents bedrock intersected in the flank of the central uplift. Both 7A and 8A suevite intersections differ from suevites outside of the northern crater rim. Deep drilling results confirmed the gross structure of the crater as imaged by the pre-drilling seismic surveys. Borehole geophysical studies conducted in the two boreholes confirmed the low seismic velocities for the post-impact sediments (less than 1800 m/s) and the impactites (2600-3300 m/s). The impactites exhibit very high porosities (up to 30 vol%), which has important implications for mechanical rock stability. The statistical analysis of the velocities and densities reveals a seismically transparent impactite sequence (free of prominent internal reflections). Petrophysical core analyses provide no support for the presence of a homogeneous magnetic unit (= melt breccia) within the center of the structure. Borehole vector magnetic data point to a patchy distribution of highly magnetic rocks within the impactite sequence. The lack of a coherent melt sheet, or indeed of any significant amounts of melt rock in the crater fill, is in contrast to expectations from modeling and pre-drilling geophysics, and presents an interesting problem for comparative studies and requires re-evaluation of existing data from other terrestrial impact craters, as well as modeling parameters. © The Meteoritical Society, 2007. Printed in USA. Review 2007 English 10869379 10.1111/j.1945-5100.2007.tb01057.x Meteoritics and Planetary Science 42 University of Arkansas 483 – 511 4-5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-34250687519&doi=10.1111%2fj.1945-5100.2007.tb01057.x&partnerID=40&md5=99cf93e5b9540d6fb93a7d4fd5110c08 Cited by: 79; All Open Access, Green Open Access Christian Koeberl Bernd Milkereit Jonathan T. Overpeck Christopher A. Scholz Philip Y.O. Amoako Daniel Boamah Sylvester K. Danuor Tobias Karp Jochem Kueck Robert E. Hecky John W. King John A. Peack article Bulut2007 Joint inversion for hypocentral parameters and the velocity field is nowadays a state of the art tool to obtain high-resolution images of seismically active regions. In this study, we focus on the location accuracy of aftershocks of the 1999 Mw = 7.4 İzmit (NW Turkey) earthquake. We obtained a new velocity model for the region, and depicted its improvement on absolute locations in terms of uncertainty and misfit. Two well-developed aftershock clusters located in the Akyazi area and Karadere-Düzce region, were analyzed in detail based on a waveform cross-correlation approach that allowed improving the location accuracy by a factor of 6. Relocation results reveal that hypocenters form narrow planes of activity that can be correlated with focal mechanisms of the larger aftershocks as well as nearby clouds of activity with no internal structure down to the resolved scale of ∼300 m. Copyright 2007 by the American Geophysical Union. 2007 English 00948276 10.1029/2007GL031154 Geophysical Research Letters 34 GeoForschungsZentrum Potsdam, Haus D Projektbereich 3.2, Telegrafenberg D-14473 Potsdam, Germany; Department of Geophysics, Kandilli Observatory and Earthquake Research Institute, Boǧaziçi University, 34680 Çengelköy Istanbul, Turkey 20 Earthquake effects; Mathematical models; Seismic waves; Waveform analysis, Hypocenters; Seismically active regions; Turkey, Seismology, aftershock; earthquake event; earthquake hypocenter; fault plane; focal mechanism; seismic velocity, Eurasia; Izmit; Kocaeli [Turkey]; Turkey https://www.scopus.com/inward/record.uri?eid=2-s2.0-37349111761&doi=10.1029%2f2007GL031154&partnerID=40&md5=6d5d55ef09eca82ae5e06f5e406c2cd7 cited By 41 F. Bulut M. Bohnhoff M. Aktar G. Dresen article Cheng200855 Article 2007 Drilling Engineering 7 49-51 Z. Lin G. Yang J. Zhang article Cheng200855 Article 2007 Drilling Engineering 10 69-71 Z. Lin G. Yang J. Zhang B. Jiang article Juschus2007187 Lake El'gygytgyn is situated in a 3.6 Ma old impact crater in north-eastern Siberia and probably represents one of the most complete archives of Arctic climate change. Investigated here is the potential of infra-red stimulated luminescence (IRSL) using the single-aliquot regenerative-dose (SAR) approach for dating sediments from this lake. Independent age control is available from a published age model of a parallel core that is based on tuning sediment proxies with regional insolation and the results of previous multiple aliquot IRSL dating. Although the site is located within volcanic bedrock, anomalous fading seems to have little effect on the calculated ages. The modelled water content for the entire time of burial is seen as the most prominent uncertainty at this particular site. Despite these potential error sources, SAR-IRSL ages are in acceptable agreement with the given timeframe and clearly point to the possibility to establish independent chronologies at this site up to at least 400,000 years. © 2006. 2007 English 18711014 10.1016/j.quageo.2006.05.006 Quaternary Geochronology 2 187-194 Institute for Geophysics and Geology, University of Leipzig, Talstrasse 35, D 04103 Leipzig, Germany; Institute of Geological Sciences, Universität Bern, Baltzerstrasse 1-3, CH 3012 Bern, Switzerland; Geographisches Institut, Universität zu Köln, Albertus-Magnus-Platz, D 50923 Köln, Germany 1-4 age determination; bedrock; climate change; crater; fine grained sediment; geochronology; insolation; lacustrine deposit; luminescence dating, Chukchi; Eurasia; Lake El'gygytgyn; Russian Federation; Siberia https://www.scopus.com/inward/record.uri?eid=2-s2.0-34548032560&doi=10.1016%2fj.quageo.2006.05.006&partnerID=40&md5=7d5c834fc7b89fff86c657ae4d2bf741 cited By 37 O. Juschus F. Preusser M. Melles U. Radtke conference Vasconcelos20072175 The San Andreas Fault Observatory at Depth provides the most comprehensive set of data on the structure and dynamics of the San Andreas fault. We use two independent experiments recorded by the seismometer arrays of the SAFOD Pilot and Main Holes to resolve the localized structure of the San Andreas fault zone and of an intermediate fault zone at depth. From Pilot Hole recordings of the drilling noise coming from the Main Hole, we reconstruct the waves that propagate between the Pilot Hole sensors and use them to image the fault zone structure. The use of correlated drilling noise leads to a high-resolution image of a major transform fault zone. Another independent image is generated from the detonation of a surface explosive charge recorded at a large 178-sensor array placed in the Main Hole. The images reveal the San Andreas fault as well as an active blind fault zone that could potentially rupture. This is confirmed by two independent methods. The structure and the activity of the imaged faults is of critical importance in understanding the current stress state and activity of the San Andreas fault system. © 2007 Society of Exploration Geophysicists. All rights reserved. 2007 English 9781604238976 Society of Exploration Geophysicists - 77th SEG International Exposition and Annual Meeting, SEG 2007 Society of Exploration Geophysicists 2175-2179 Center for Wave Phenomena, Colorado School of Mines, Golden, CO 80401, United States; Earth and Ocean Sciences Division, Duke University, Durham, NC 27708, United States; Paulsson Geophysical Services, Inc., Brea, CA 92821, United States Explosives; Geophysical prospecting; Infill drilling; Strike-slip faults; Transform faults, Current stress; Drilling noise; Explosive charges; Fault zone structures; High resolution image; Localized structures; San Andreas fault; Structure and dynamics, Structural geology https://www.scopus.com/inward/record.uri?eid=2-s2.0-85055726729&partnerID=40&md5=a5f522ca1e790a91b613e016989cedf1 cited By 0 I. Vasconcelos S.T. Taylor R. Snieder J.A. Chavarria P. Sava P. Malin article Vasconcelos20072175 The San Andreas Fault Observatory at Depth provides the most comprehensive set of data on the structure and dynamics of the San Andreas fault. We use two independent experiments recorded by the seismometer arrays of the SAFOD Pilot and Main Holes to resolve the localized structure of the San Andreas fault zone and of an intermediate fault zone at depth. From Pilot Hole recordings of the drilling noise coming from the Main Hole, we reconstruct the waves that propagate between the Pilot Hole sensors and use them to image the fault zone structure. The use of correlated drilling noise leads to a high-resolution image of a major transform fault zone. Another independent image is generated from the detonation of a surface explosive charge recorded at a large 178-sensor array placed in the Main Hole. The images reveal the San Andreas fault as well as an active blind fault zone that could potentially rupture. This is confirmed by two independent methods. The structure and the activity of the imaged faults is of critical importance in understanding the current stress state and activity of the San Andreas fault system. © 2007 Society of Exploration Geophysicists. 2007 English 10523812 10.1190/1.2792918 SEG Technical Program Expanded Abstracts 26 Society of Exploration Geophysicists 2175-2179 Center for Wave Phenomena, Colorado School of Mines, Golden, CO 80401, United States; Earth and Ocean Sciences Division, Duke University, Durham, NC 27708, United States; Paulsson Geophysical Services, Inc., Brea, CA 92821, United States 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-37549020744&doi=10.1190%2f1.2792918&partnerID=40&md5=d1037bc652a9bcf1ed611207c07c278b cited By 3 I. Vasconcelos S.T. Taylor R. Snieder J.A. Chavarria P. Sava P. Malin conference Soga20072591 Methane hydrate soil is a natural soil deposit that contains methane hydrate in its pores. Methane hydrate is a metastable solid material and it bonds the soil particles together. Methane hydrate soil can only develop and exist under a condition of high pressure and low temperature. Hence, natural methane hydrate soils are usually found under deep seabed or permafrost regions. This paper synthesises the available data of engineering properties of natural methane hydrate soil samples retrieved at four different sites; Nankai Trough, Mallik-Mackenzie Delta, Blake Ridge and Hydrate Ridge. The geotechnical data are obtained from index tests, oedometer tests, triaxial compression tests and wave velocity measurements. The effects of hydrate growth pattern and hydrate saturation on their mechanical properties are discussed. © 2007 Taylor & Francis Group, London. 2007 English 9780415402675 Characterisation and Engineering Properties of Natural Soils 3-4 2591-2642 University of Cambridge, Cambridge, United Kingdom; Technion, Israel Institute of Technology, Haifa, Israel Blake Ridge; Deep sea-bed; Engineering properties; Geotechnical data; High pressure; Hydrate growth; Hydrate ridge; Hydrate saturation; Index tests; Low temperatures; Metastable solids; Methane hydrates; Natural methane; Natural soils; Oedometer tests; Permafrost region; Soil particles; Soil sample; Triaxial compression tests; Wave velocity, Compression testing; Hydration; Mechanical properties; Methane; Permafrost; Soil mechanics; Soil testing; Soils; Velocity measurement, Gas hydrates https://www.scopus.com/inward/record.uri?eid=2-s2.0-84863229857&partnerID=40&md5=3bea116d346d154220d36fd639197dd5 cited By 97 K. Soga S.L. Lee M.Y.A. Ng A. Klar article Song2007243 The main objective of the Taiwan Chelungpu-fault Drilling Project (TCDP) was to conduct an in-depth probe into a fault zone of recent major activity so as to gain a better understanding of and more insight into the physical, mechanical and chemical properties involved. By the end of 2004, with the completion of the drilling of Hole-A, cuttings from 0 to 431.34 m and cores from a 431.34- to 2003.26-m depth had been obtained. Stratigraphically, the Pliocene to Pleistocene Cholan Formation is found from the surface to a 1029-m depth and is predominantly composed of sandstone and sandstone-siltstone alternations with weak to intense bioturbation. The Pliocene Chinshui Formation is observed from a depth of 1029- to 1303-m and predominantly consists of siltstone with weak bioturbation. From 1303- to 1712-m down there is the late Miocene to early Pliocene Kueichulin Formation which is predominantly composed of massive sandstone with minor siltstone. Below 1712 m, the Formation again resembles the younger Cholan Formation with mollusca-rich, thick, layered shale and heavy bioturbated sandstone. Four types of fault-related rocks are identified in the cores. They are the fault breccia, gouges, foliated and non-foliated cataclasites and pseudotachylytes. At least six major fault zones are found in the cores: FZ1111, FZ1153, FZ1220, FZ1580, FZ1712, and FZ1812. Among these, FZ1111 most probably corresponds to the slip surface of the Chi-Chi earthquake, the Chelungpu fault, while FZ1712 very likely represents the Sanyi fault. 2007 English 10170839 10.3319/TAO.2007.18.2.243(TCDP) Terrestrial, Atmospheric and Oceanic Sciences 18 243-269 Department of Geosciences, National Taiwan University, Taipei, Taiwan; Kochi Institute for Core Sample Research, Japan Agency for Marine-Earth Science and Technology, Kochi, Japan; Department of Earth Sciences, Institute of Geophysics, National Central University, Chung-Li, Taiwan 2 chemical property; fault zone; lithology; lithostratigraphy; mechanical property; Miocene; physical property; Pleistocene; Pliocene, Asia; Eurasia; Far East; Taiwan, Mollusca https://www.scopus.com/inward/record.uri?eid=2-s2.0-34547604009&doi=10.3319%2fTAO.2007.18.2.243%28TCDP%29&partnerID=40&md5=9b0f14ad8d522907aaad3aa9e7ba7fdd cited By 51 S.-R. Song L.-W. Kuo E.-C. Yeh C.-Y. Wang J.-H. Hung K.-F. Ma article Ma200733 2007 English 18168957 10.2204/iodp.sd.s01.10.2007 Scientific Drilling Integrated Ocean Drilling Program 33-34 Department of Earth Science and Institute of Geophysics, National Central University, No.300, Johngda Rd., Johngli City, Taoyuan County 32001, Taiwn, Taiwan; Solid Earth Science Group, Department of Earth and Planetary Sciences, The University of Tokyo, Faculty of Science Building #1, Hongou 7-3-1, Bunkyo-ku,ing Tokyo, 113-0033, Japan 1 SUPPL. 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-78651566829&doi=10.2204%2fiodp.sd.s01.10.2007&partnerID=40&md5=1381297ab6bd7b1d4ed8ac3fbb8e3ebb cited By 1 K.-F. Ma H. Tanaka article Nolan200717 A survey of the modern physical setting of Lake El'gygytgyn, northeastern Siberia, is presented here to facilitate interpretation of a 250,000-year climate record derived from sediment cores from the lake bottom. The lake lies inside a meteorite impact crater that is approximately 18 km in diameter, with a total watershed area of 293 km2, 110 km2 of which is lake surface. The only surface water entering the lake comes from the approximately 50 streams draining from within the crater rim; a numbering system for these inlet streams is adopted to facilitate scientific discussion. We created a digital elevation model for the watershed and used it to create hypsometries, channel networks, and drainage area statistics for each of the inlet streams. Many of the streams enter shallow lagoons dammed by gravel berms at the lakeshore; these lagoons may play a significant role in the thermal and biological dynamics of the lake due to their higher water temperatures (&gt;6°C). The lake itself is approximately 12 km wide and 175 m deep, with a volume of 14.1 km3. Water temperature within a column of water near the center of this oligotrophic, monomictic lake never exceeded 4°C over a 2.5 year record, though the shallow shelves (&lt;10 m) surrounding the lake can reach 5°C in summer. Though thermally stratified in winter, the water appears completely mixed shortly after lake ice breakup in July. Mean annual air temperature measured about 200 m from the lake was -10.3°C in 2002, and an unshielded rain gage there recorded 70 mm of rain in summer of 2002. End of winter snow water equivalent on the lake was approximately 110 mm in May 2002. Analysis of NCEP reanalysis air temperatures (1948-2002) reveals that the 8 warmest years and 10 warmest winters have occurred since 1989, with the number of days below -30°C dropping from a pre-1989 mean of 35 to near 0 in recent years. The crater region is windy as well as cold, with hourly wind speeds exceeding 13.4 m s-1 (30 mph) typically at least once each month and 17.8 m s-1 (40 mph) in winter months, with only a few calm days per month; wind may also play an important role in controlling the modern shape of the lake. Numerous lines of evidence suggest that the physical hydrology and limnology of the lake has changed substantially over the past 3.6 million years, and some of the implications of these changes on paleoclimate reconstructions are discussed. © 2006 Springer Science+Business Media B.V. 2007 English 09212728 10.1007/s10933-006-9020-y Journal of Paleolimnology 37 17-35 Institute of Northern Engineering, University of Alaska Fairbanks, 525 Duckering Bldg., Fairbanks, AK 99775-5860, United States; Department of Geosciences, University of Massachusetts, Morrill Science Building, 611 N. Pleasant Street, Amherst, MA 01003, United States 1 crater lake; digital elevation model; hydrology; lacustrine deposit; lacustrine environment; lake dynamics; limnology; meteorology; sediment core, Chukchi; Eurasia; Lake El'gygytgyn; Russian Federation https://www.scopus.com/inward/record.uri?eid=2-s2.0-33845935584&doi=10.1007%2fs10933-006-9020-y&partnerID=40&md5=c473e75354a9001cc43af34442652dd0 cited By 83 M. Nolan J. Brigham-Grette article Scholz200716416 The environmental backdrop to the evolution and spread of early Homo sapiens in East Africa is known mainly from isolated outcrops and distant marine sediment cores. Here we present results from new scientific drill cores from Lake Malawi, the first long and continuous, high-fidelity records of tropical climate change from the continent itself. Our record shows periods of severe aridity between 135 and 75 thousand years (kyr) ago, when the lake's water volume was reduced by at least 95%. Surprisingly, these intervals of pronounced tropical African aridity in the early late-Pleistocene were much more severe than the Last Glacial Maximum (LGM), the period previously recognized as one of the most arid of the Quaternary. From these cores and from records from Lakes Tanganyika (East Africa) and Bosumtwi (West Africa), we document a major rise in water levels and a shift to more humid conditions over much of tropical Africa after ≈70 kyr ago. This transition to wetter, more stable conditions coincides with diminished orbital eccentricity, and a reduction in precession-dominated climatic extremes. The observed climate mode switch to decreased environmental variability is consistent with terrestrial and marine records from in and around tropical Africa, but our records provide evidence for dramatically wetter conditions after 70 kyr ago. Such climate change may have stimulated the expansion and migrations of early modern human populations. © 2007 by The National Academy of Sciences of the USA. Article 2007 English 10916490 10.1073/pnas.0703874104 Proceedings of the National Academy of Sciences of the United States of America 104 16416 – 16421 42 Africa, Eastern; Animals; Evolution; Hominidae; Humans; Natural Disasters; Paleontology; Population; Tropical Climate; Homo sapiens; Africa; article; climate change; drought; environment; evolution; human; migration; nonhuman; Pleistocene; priority journal https://www.scopus.com/inward/record.uri?eid=2-s2.0-36749081537&doi=10.1073%2fpnas.0703874104&partnerID=40&md5=f40e36c3f7331068c1f45b8461f35257 Cited by: 332; All Open Access, Green Open Access Christopher A. Scholz Thomas C. Johnson Andrew S. Cohen John W. King John A. Peck Jonathan T. Overpeck Michael R. Talbot Erik T. Brown Leonard Kalindekafe Philip Y. O. Amoako Robert P. Lyons Timothy M. Shanahan Isla S. Castañeda Clifford W. Heil Steven L. Forman Lanny R. McHargue Kristina R. Beuning Jeanette Gomez James Pierson article Hunze2007779 Bosumtwi is a very well-preserved 1.07 Myr old, complex terrestrial impact crater located in south-central Ghana, West Africa. The impact structure has a diameter of about 10.5 km and was formed in 2.1-2.2 Gyr Precambrian metasedimentary and metavolcanic rocks. Drilling and logging was carried out during the Lake Bosumtwi Drilling Project (BCDP) which was supported by the International Continental Scientific Drilling Program (ICDP). One of the aims of this project is to achieve detailed information on the subsurface structure and crater fill of one of the best preserved large young impact structures. We interpreted the wireline logs and televiewer images. The physical properties including shallow resistivity, p-wave velocity, magnetic susceptibility, and borehole diameter of the breccia differ significantly from those of the meta-graywackes and slate/phyllites. Fractures observed in the televiewer images are interpreted to determine their characteristic structural features. The fracture dip angles are steep (50-70°) and the two main dip directions are southeast and southwest. Most fractures observed in the borehole are open. The indicated main stress direction is north-south. © The Meteoritical Society, 2007. Printed in USA. Article 2007 English 10869379 10.1111/j.1945-5100.2007.tb01074.x Meteoritics and Planetary Science 42 University of Arkansas 779 – 792 4-5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-34250673565&doi=10.1111%2fj.1945-5100.2007.tb01074.x&partnerID=40&md5=44cf4765b47b9ae95c3ac2bee78a6c3c Cited by: 9; All Open Access, Bronze Open Access Sabine Hunze Thomas Wonik article Tobin20075 2007 English 18168957 10.2204/iodp.sd.s01.80.2007 Scientific Drilling 5-16 Department of Geology and Geophysics, University of Wisconsin-Madison, 1215 West Dayton Street, Madison, Wis. 53706, United States; Center for Deep Earth Exploration (CDEX), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 3173-25 Showa-machi, Kanazawa-ku, Yokohama, Kanagawa, 236-0001, Japan; Marine Geodynamics, IFM-GEOMAR, Wischhofstr. 1-3, 24148, Kiel, Germany; U.S. Geological Survey, MS977, 345 Middlefield Road, Menlo Park, Calif., 94025, United States; Department of Earth and Planetary Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan 1 SUPPL. 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-77954510216&doi=10.2204%2fiodp.sd.s01.80.2007&partnerID=40&md5=4ae2928358e732e747c19e3ebbec6a3a cited By 6 H. Tobin H. Ito J. Behrmann S. Hickman G. Kimura article Morgan200742 2007 10.2204/iodp.sd.4.11.2007 Scientific Drilling 42-44 Department of Earth Science and Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom; University of Texas Institute for Geophysics, J.J. Pickle Research Campus, 10100 Burnet Rd., Austin, TX 78759-8500, United States; Natural Resources Canada, 580 Booth Street, Ottawa, ON K1A 0E4, Canada; Instituto de Geofisica, Universidad Nacional Autónoma de México, Del Coyoacan Mexico D.F. 04510, Mexico; Department of Earth Sciences, University of Cambridge, Madingley Rise, Cambridge CB3 0EZ, United Kingdom; Centro de Investigación Cientifica de Yucatán, Calle 8 39, Cancun, México 77500, Mexico; Lunar and Planetary Laboratory, University of Arizona, Tuscon, AZ 85721, United States 4 https://www.scopus.com/inward/record.uri?eid=2-s2.0-69649099663&doi=10.2204%2fiodp.sd.4.11.2007&partnerID=40&md5=18e83ff3df39616811dae65a0e2f3947 cited By 2 J.V. Morgan G. Christeson S. Gulick R. Grieve J. Urrutia P. Barton M. Rebolledo J. Melosh article Grygar200750 The environmental record from Lake Baikal, Russia, from 310 to 50 ky BP (MIS 9a to MIS 3) was interpreted using rock magnetic, UV-Vis spectral, mineralogical, and diatom analyses. The age model was based on a correlation of the diatom and chemical weathering records and the summer insolation curve at 55°N and checked against an age model based on the proxy of relative palaeointensity of the Earth's magnetic field. Peaks in chemical weathering within the watershed, inferred from maximum concentration of magnetic and coloured minerals and mica, the lowest mean Fe oxidation state in silicates and highs in expandable clay minerals correlated with the Northern Hemisphere summer insolation minima at 55°N. Reconstructed changes in weathering intensity are better correlated to insolation patterns than to global ice volume records. We propose a scheme of yet missing palaeoenvironmental interpretation of the diatom assemblage, including also some extinct species. Aulacoseira baicalensis and Aulacoseira skvortzowii were abundant in the early stages of lake flora recovery immediately after deglaciation and during MIS 7e and MIS 5e; periods of more pronounced continental climate and peak chemical weathering. Stephanodiscus formosus var. minor, Cyclotella minuta and Cyclotella ornata dominated in intervals of decreased seasonality and decreased humidity at the end of most interglacial/interstadial diatom zones. Stephanodiscus grandis, Stephanodiscus carconeiformis and Stephanodiscus formosus were ubiquitous between MIS 8 and MIS 5, an interval marked by high seasonality, i.e., large differences between winter and summer insolation, and low humidity revealed by a low hydrolysis of expandable clay minerals in the watershed. Diatom concentrations peaked in the climatic optima of MIS 7e and MIS 5e and in the short periods marked by shifts to warmer conditions in the upper sections of MIS 5: MIS 5c (103-99 ky BP), MIS 5b (90-88 ky BP), and MIS 5a (84-79 ky BP) in which increased humidity resulted in enhanced hydrolysis of clay minerals. No such short similar climatic optimums were found from MIS 9a to MIS 6. Sharp climate deteriorations recorded in the diatom and clay mineral records at 107, 94, and 87 ky BP, however, occurred within 1-2 ky of cold extremes in North Atlantic sea surface temperature emphasizing the strong teleconnections between the two localities. © 2007 Elsevier B.V. All rights reserved. Article 2007 English 00310182 10.1016/j.palaeo.2007.03.001 Palaeogeography, Palaeoclimatology, Palaeoecology 250 50 – 67 1-4 Eurasia; Lake Baikal; Russian Federation; Aulacoseira baicalensis; Aulacoseira skvortzowii; Bacillariophyta; Cyclotella; Cyclotella minuta; Stephanodiscus; climate change; diatom; interglacial; interstadial; lacustrine deposit; magnetic field; Northern Hemisphere; orbital forcing; proxy climate record; record; spectroscopy; watershed; weathering https://www.scopus.com/inward/record.uri?eid=2-s2.0-34249293990&doi=10.1016%2fj.palaeo.2007.03.001&partnerID=40&md5=c7beb939f41906f3f8bb58536b53b661 Cited by: 12 Tomas Grygar Anna Bláhová David Hradil Petr Bezdicka Jaroslav Kadlec Petr Schnabl George Swann Hedi Oberhänsli article Litt200740 2007 English 18168957 10.2204/iodp.sd.4.13.2007 Scientific Drilling 40-41 Institute of Paleontology, University of Bonn, Nussallee 8, 53115 Bonn, Germany; Faculty of Geosciences, University of Bremen, Klagenfurter Straße, 28359 Bremen, Germany; Department of Geology, Yuzunou Yl Universitesi, Zeve Kampusu, 65080 Van, Turkey; Department of Anthropology, Yuzuncu Yl Universitesi, Zeve Kampusu, 65080 Van, Turkey 4 https://www.scopus.com/inward/record.uri?eid=2-s2.0-67349120599&doi=10.2204%2fiodp.sd.4.13.2007&partnerID=40&md5=974d8192a37fbea2910751d8e4247a03 cited By 6 T. Litt S. Krastel S. Orcen M. Karabiyikoglu article Colman20072281 We review Late Cenozoic climate and environment changes in the western interior of China with an emphasis on lacustrine records from Lake Qinghai. Widespread deposition of red clay in the marginal basins of the Tibetan Plateau indicates that the Asian monsoon system was initially established by ∼8 Ma, when the plateau reached a threshold altitude. Subsequent strengthening of the winter monsoon, along with the establishment of the Northern Hemisphere ice sheets, reflects a long-term trend of global cooling. The few cores from the Tibetan Plateau that reach back a million years suggest that they record the mid-Pleistocene transition from glacial cycles dominated by 41 ka cycles to those dominated by 100 ka cycles. During Terminations I and II, strengthening of the summer monsoon in China's interior was delayed compared with sea level and insolation records, and it did not reach the western Tibetan Plateau and the Tarim Basin. Lacustrine carbonate δ18O records reveal no climatic anomaly during MIS3, so that high terraces interpreted as evidence for extremely high lake levels during MIS3 remain an enigma. Following the Last Glacial Maximum (LSM), several lines of evidence from Lake Qinghai and elsewhere point to an initial warming of regional climate about 14 500 cal yr BP, which was followed by a brief cold reversal, possibly corresponding to the Younger Dryas event in the North Atlantic region. Maximum warming occurred about 10 000 cal yr BP, accompanied by increased monsoon precipitation in the eastern Tibetan Plateau. Superimposed on this general pattern are small-amplitude, centennial-scale oscillations during the Holocene. Warmer than present climate conditions terminated about 4000 cal yr BP. Progressive lowering of the water level in Lake Qinghai during the last half century is mainly a result of negative precipitation-evaporation balance within the context of global warming. © 2007. Article 2007 English 02773791 10.1016/j.quascirev.2007.05.002 Quaternary Science Reviews 26 2281 – 2300 17-18 Asia; Atlantic Ocean; Atlantic Ocean (North); China; Eurasia; Far East; Qinghai-Xizang Plateau; Qionghai Lake; Sichuan; Tarim Basin; Xinjiang Uygur; Carbonates; Glaciers; Global warming; Precipitation (meteorology); Sea level; carbonate; Cenozoic; climate change; climate conditions; comparative study; global warming; historical record; Holocene; ice sheet; Last Glacial Maximum; marginal basin; Northern Hemisphere; regional climate; Lake Qinghai; Tibetan Plateau; Climate change https://www.scopus.com/inward/record.uri?eid=2-s2.0-35548973556&doi=10.1016%2fj.quascirev.2007.05.002&partnerID=40&md5=5e5e86695edeb8f4e08bc99baffd5f69 Cited by: 150; All Open Access, Green Open Access Steven M. Colman Shi-Yong Yu ZhiSheng An Ji Shen A.C.G. Henderson article Zanoth2007 The leaky mode is a possible attenuation mechanism of seismic waves propagating along lamination in gas-hydrate-bearing sediment layers. This horizontal propagation attenuation mechanism occurs when a high-velocity layer is embedded in a low-velocity zone. This is a typical situation for gas hydrate occurrences. To quantify this attenuation mechanism, a 2D digital rock model based on the crosswell data of the Mallik 2002 Gas Hydrate Production Research Well Program is used. For simplicity, our elastic simulations exclude attenuation mechanisms like scattering loss or intrinsic absorption. We demonstrate that the leaky mode is a significant horizontal attenuation mechanism that cannot be neglected. The effective attenuation of gas-hydrate-bearing sediments is a combination of intrinsic and scattering attenuation by small-scale heterogeneties and the leaky mode. © 2007 Society of Exploration Geophysicists. 2007 English 00168033 10.1190/1.2750375 Geophysics 72 Society of Exploration Geophysicists E159-E163 Freie Universität, Fachbereich Geophysik, Berlin, Germany; ETH Zurich, Geological Institute, Zurich, Switzerland; Spectraseis, Zurich, Switzerland 5 Absorption; Computer simulation; Elastic waves; Mathematical models; Seismic waves; Two dimensional; Wave propagation, Gas-hydrate-bearing sediment; Seismic attenuation, Gas hydrates, absorption; gas hydrate; seismic attenuation; seismic velocity; seismic wave; simulation; wave propagation https://www.scopus.com/inward/record.uri?eid=2-s2.0-34548533646&doi=10.1190%2f1.2750375&partnerID=40&md5=26fa413198f46862b481dc73b1f97500 cited By 7 S.R. Zanoth E.H. Saenger O.S. Krüger S.A. Shapiro article Coney2007569 Lithostratigraphic and petrographic studies of drill core samples from the 545.08 m deep International Continental Scientific Drilling Program (ICDP) borehole LB-07A in the Bosumtwi impact structure revealed two sequences of impactites below the post-impact crater sediments and above coherent basement rock. The upper impactites (333.38-415.67 m depth) comprise an alternating sequence of suevite and lithic impact breccias. The lower impactite sequence (415.67-470.55 m depth) consists essentially of monomict impact breccia formed from meta-graywacke with minor shale, as well as two narrow injections of suevite, which differ from the suevites of the upper impactites in color and intensity of shock metamorphism of the clasts. The basement rock (470.55-545.08 m depth) is composed of lower greenschist-facies metapelites (shale, schist and minor phyllite), meta-graywacke, and minor meta-sandstone, as well as interlaminated quartzite and calcite layers. The basement also contains a number of suevite dikelets that are interpreted as injection veins, as well as a single occurrence of granophyric-textured rock, tentatively interpreted as a hydrothermally altered granitic intrusion likely related to the regional pre-impact granitoid complexes. Impact melt fragments are not as prevalent in LB-07A suevite as in the fallout suevite facies around the northern crater rim; on average, 3.6 vol% of melt fragments is seen in the upper suevites and up to 18 vol% in the lower suevite occurrences. Shock deformation features observed in the suevites and polymict lithic breccias include planar deformation features in quartz (1 to 3 sets), rare diaplectic quartz glass, and very rare diaplectic feldspar glass. Notably, no ballen quartz, which is abundant in the fallout suevites, has been found in the within-crater impact breccias. An overall slight increase in the degree of shock metamorphism occurs with depth in the impactites, but considerably lower shock degrees are seen in the suevites of the basement rocks, which show similar features to each other. The bulk of the suevite in LB-07A appears to have been derived from the <35 GPa shock zone of the transient crater. © The Meteoritical Society, 2007. Printed in USA. Article 2007 English 10869379 10.1111/j.1945-5100.2007.tb01062.x Meteoritics and Planetary Science 42 University of Arkansas 569 – 589 4-5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-34250686622&doi=10.1111%2fj.1945-5100.2007.tb01062.x&partnerID=40&md5=50a1bdbdd2acf2952bad0f4684cbfd0a Cited by: 29; All Open Access, Bronze Open Access Louise Coney Roger L. Gibson Wolf Uwe Reimold Christian Koeberl article Ugalde2007859 The Bosumtwi impact structure of central Ghana was drilled in 2004 as part of the International Continental Scientific Drilling Program (ICDP). A vast amount of geoscience data is available from the pre-site surveys and the actual drilling phase. A 3-D gravity model was constructed and calibrated with the available data from the two ICDP boreholes, LB-07A and LB-08A. The 3-D gravity model results agree well with both the sediment thickness and size of the central uplift revealed by previously collected seismic data, and with the petrophysical data from the LB-08A and LB-07A core materials and the two borehole logs. Furthermore, the model exhibits lateral density variations across the structure and refines the results from previous 2.5-D modeling. An important new element of the 3-D model is that the thickness of the intervals comprising polymict lithic impact breccia and suevite, monomict lithic breccia and fractured basement is much smaller than that predicted by numerical modeling. © The Meteoritical Society, 2007. Printed in USA. Article 2007 English 10869379 10.1111/j.1945-5100.2007.tb01081.x Meteoritics and Planetary Science 42 University of Arkansas 859 – 866 4-5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-34250661060&doi=10.1111%2fj.1945-5100.2007.tb01081.x&partnerID=40&md5=d34db7d32a5c05d17e87f405c35979c0 Cited by: 9; All Open Access, Bronze Open Access Hernan Ugalde Sylvester K. Danuor Bernd Milkereit article Forman200777 This study focused on the luminescence dating of sediments from Lake El'gygytgyn, a meteorite impact crater 100 km north of the Arctic Circle in northeast Siberia, formed 3.58 Ma ago. The sediment is principally eolian deposited in to a lake with nearly permanently ice. The fine-grained polymineral and quartz extracts taken from nine distinct levels from the upper 12.3 m of sediment core PG1351 were dated by infrared stimulated (IRSL) and green stimulated luminescence (GSL) using multiple aliquot additive dose procedures. The veracity of these ages is evaluated by comparing to an age model for the core derived from magnetic excursions and from correlation of variations of the magnetic susceptibility record to similar magnitude variations in δ 18O in the Greenland Ice core record. The IRSL ages from the upper 9 m of core correspond well with the independent age control for the past ca. 200 ka. However, sediments deeper in the core at 12.3 m with an inferred age of ca. 250 ka age yield a saturated IRSL response and therefore a non-finite OSL age. The youngest sediment dated from 0.70 m depth yielded the IRSL age of ca. 11.5 ka, older than the corresponding age of 9.3-8.8 ka, indicating a discrepancy in dating the youngest sediments in the upper 1 m of core. This study confirms the utility of IRSL by the multiple aliquot additive dose method to date sediments &lt;200 ka old from eastern Siberia. © 2006 Springer Science+Business Media B.V. 2007 English 09212728 10.1007/s10933-006-9024-7 Journal of Paleolimnology 37 77-88 Department of Earth and Environmental Sciences, University of Illinois, 845 W. Taylor Street, Chicago, IL 60607-7059, United States; Department of Geosciences, University of Massachusetts, Morrill Science Center, 611 North Pleasant Street, Amherst, MA 01003-9297, United States; GeoForschungs Zentrum Potsdam, Telegrafenberg Section 3.3, D-14473 Potsdam, Germany; Institute of Geophysics and Geology, University of Leipzig, Leipzig, Germany 1 crater lake; eolian deposit; geochronology; lacustrine deposit; luminescence dating; paleoenvironment; sediment core, Chukchi; Eurasia; Lake El'gygytgyn; Russian Federation https://www.scopus.com/inward/record.uri?eid=2-s2.0-33845955276&doi=10.1007%2fs10933-006-9024-7&partnerID=40&md5=2f73f5368f322f4247bc8f7acd6a527a cited By 30 S.L. Forman J. Pierson J. Gómez J. Brigham-Grette N.R. Nowaczyk M. Melles article Enkin2007 The J meter coercivity spectrometer is a machine capable of rapid and simple measurement of magnetic hysteresis, isothermal remanence acquisition and magnetic viscosity of rocks and sediments. The J meter was used to study a suite of samples collected from strata in the gas hydrate-bearing JAPEX/JNOC/GSC Mallik 5L-38 well (69.5°N, 134.6°W) in the Mackenzie Delta of the northwestern Canadian Arctic. The Day plot of magnetic hysteresis ratios for these samples is exotic in that the points do not plot along a hyperbola as is usually observed. Rather, they plot as a scatter which is shown to contour into vertical slices using coercivity field (HC) or saturation magnetization (JS), and horizontal slices using the relative quantity of superparamagnetism (JSPM/JS). Optical microscopy reveals that the magnetic minerals are detrital magnetite and authigenic greigite. Greigite is dominant in sands which in situ had &gt;70% gas hydrate saturation and in silts in which gas hydrate growth was blocked by insufficient porosity. We infer that the silts were the accumulation sites for solutes which had been excluded from the pore waters in neighboring coarser-grained sediments during the course of gas hydrate formation. Consequently, we conclude that magnetic properties are related to gas hydrate-related processes, and as such, may have potential as a method of remote sensing for gas hydrate deposits. Copyright 2007 by the American Geophysical Union. 2007 English 21699313 10.1029/2006JB004638 Journal of Geophysical Research: Solid Earth 112 Blackwell Publishing Ltd Geological Survey of Canada-Pacific, PO Box 6000, Sidney, BC V8L 4B2, Canada; Department of Geology, Kazan State University, Kremlyevskaya Str. 18, 420008 Kazan, Russian Federation; Department of Chemistry and Geoscience, Camosun College, 3100 Foul Bay road, Victoria, BC V8P 4J2, Canada 6 chemical alteration; detrital deposit; diagenesis; formation mechanism; gas hydrate; greigite; hysteresis; isotherm; magnetic field; magnetic property; magnetite; porosity; remanent magnetization; viscosity, Canada; Mackenzie Delta; North America; Northwest Territories https://www.scopus.com/inward/record.uri?eid=2-s2.0-34548433885&doi=10.1029%2f2006JB004638&partnerID=40&md5=bbd39c0c9c8a1c2761d755f6aa6ce77d cited By 29 R.J. Enkin J. Baker D. Nourgaliev P. Iassonov T.S. Hamilton article Sun20073115 Heterogeneity of rocks, such as porosity, fractures, and fluids, causes attenuation and velocity dispersion of seismic waves, and induces waveform distortion. This distortion, once detected, offers an insight into the heterogeneous rock properties. In order to detect small velocity dispersion in the exploration seismic frequency band, a new seismic processing method has been developed for uncorrelated vibrator data. This method has been applied to the uncorrelated vibrator VSP data from Mallik gas hydrate research well, MacArthur River uranium mine area, and Outokumpu crystalline rock borehole. Different trends of Q and velocity dispersion have been detected in the above areas, which is a result of the heterogeneities in the rock volume surrounding the boreholes. © 2007 Society of Exploration Geophysicists. 2007 English 9781604238976 10523812 10.1190/1.2793117 SEG Technical Program Expanded Abstracts 26 Society of Exploration Geophysicists 3115-3119 University of Toronto, Toronto, ON, Canada; University of Alberta, Edmonton, AB, Canada 1 Boreholes; Crystalline rocks; Dispersion (waves); Gas hydrates; Petroleum prospecting; Rocks; Seismology; Velocity; Vibrators, Heterogeneous rocks; Seismic frequencies; Seismic processing; Velocity dispersion; Waveform distortions, Seismic prospecting https://www.scopus.com/inward/record.uri?eid=2-s2.0-37549069926&doi=10.1190%2f1.2793117&partnerID=40&md5=7df2d84922fe5caa33f79505ce2661fe cited By 1 L.F. Sun B. Milkereit D. Schmitt article Sone2007359 Structural characteristics of fault rocks distributed within major fault zones provide basic information in understanding the physical aspects of faulting. Mesoscopic structural observations of the drilled cores from Taiwan Chelungpu-fault Drilling Project Hole-A are reported in this article to describe and reveal the distribution of fault rocks within the Chelungpu Fault System. The Chelungpu Fault System in Hole-A was encountered at a depth of between 1050 - 1250 m where deformation structures increased. Three major fault zone structures were found at approximate depths of 1111, 1153, and 1221 m. The presence of wide fault rock regions were mostly concentrated in these 3 fault zones. The fault zone at 1111 m mainly consists of a nearly brecciated fracture zone and a clayey fault gouge zone of about 1.05 m in thickness. Fault rocks from the fault zone at 1153 m are characterized by the presence of sand grains in the matrix content, consisting of a 1.1-m thick fault breccia zone and a 0.35-m thick fault gouge zone. The fault zone at 1221 m consists of fault breccia and fault gouge of 1.15 m in total thickness. These are relatively harder and darker in color than the previous 2 fault zones. Each of the 3 fault zones contains a few layers of dark colored rocks of approximately 5 - 80 mm in thickness within the fault breccia and fault gouge zones. These dark colored rocks were found distinctively within the fault rocks. However, there relation to the process of faulting is not clearly understood and shall be discussed in detail with the aid of microscopic observations. 2007 English 10170839 10.3319/TAO.2007.18.2.359(TCDP) Terrestrial, Atmospheric and Oceanic Sciences 18 359-377 Department of Geology and Mineralogy, Kyoto University, Kyoto, Japan; Kochi Institute for Core Sample Research, Japan Agency for Marine-Earth Science and Technology, Kochi, Japan; Department of Natural Environmental Science, Kochi University, Kochi, Japan; Department of Earth Sciences, Institute of Geophysics, National Central University, Chung-Li, Taiwan; Department of Geosciences, National Taiwan University, Taipei, Taiwan; Department of Geophysics, Stanford University, Stanford, CA, United States 2 borehole; breccia; core analysis; deformation mechanism; drilling; fault gouge; fault zone; fracture zone, Asia; Eurasia; Far East; Taiwan https://www.scopus.com/inward/record.uri?eid=2-s2.0-34547578502&doi=10.3319%2fTAO.2007.18.2.359%28TCDP%29&partnerID=40&md5=3f8ad13a455eb7c097fa74f0061c2fbc cited By 33 H. Sone E.-C. Yeh T. Nakaya J.-H. Hung K.-F. Ma C.-Y. Wang S.-R. Song T. Shimamoto article https://doi.org/10.1111/j.1755-6724.2007.tb01025.x Abstract: Extensive transgression of lake water occurred during the Cretaceous Qingshankou Stage and the Nengjiang Stage in the Songliao basin, forming widespread deep-water deposits. Eleven types of microfacies of deep-water deposits have been recognized in the continuous core rocks from the SKII, including mudstone of still water, marlite, dolostone, oil shale, volcanic ashes, turbidite, slump sediment, tempestite, seismite, ostracoda limestone and sparry carbonate, which are divided into two types: microfacies generated due to gradually changing environments (I) and microfacies generated due to geological events (II). Type I is composed of some special fine grain sediments such as marlite, dolomite stone and oil shale as well as mudstone and Type II is composed of some sediments related to geological events, such as volcanic ashes, turbiditie, slump sediment, tempestite, seismite, ostracoda limestone. The formation of sparry carbonate may be controlled by factors related to both environments and events. Generally, mudstone sediments of still water can be regarded as background sediments, and the rest sediments are all event sediments, which have unique forming models, which may reflect controlling effects of climatics and tectonics. 2007 https://doi.org/10.1111/j.1755-6724.2007.tb01025.x Acta Geologica Sinica - English Edition 81 1026-1032 6 Cretaceous, deep-water deposit, model of microfacies, Songliao basin, SKII https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1755-6724.2007.tb01025.x CHENG Rihui WANG Guodong WANG Pujun GAO Youfeng article deNiem2007900 In this work the meteorite and target mass partition into high-speed ejecta during the formation of terrestrial impact craters is investigated. Multi-material hydrocode calculations are carried out through the entire excavation phase, and the mass of each material moving upwards with velocities inside a range of intervals is obtained. Impact of a 10 km diameter stony asteroid with 20 km s- 1 into the continental crust is compared for the cases of a single layer of granite, taken to be representative for the crust, and of a two-layer crust with a 3 km thick sedimentary cover of limestone on top of granite basement, more appropriate for the Chicxulub crater. The proportion of meteorite and crustal material in high-speed ejecta is found as a function of velocity and time, and maximum distances to the crater can be estimated. The resulting distal (&gt; 7000 km) ejecta mass for vertical impact is less than a percent of the impactor mass, assuming ballistic transport. Simulations of oceanic impact of a 1 km-sized stony asteroid into 5.5 km deep sea are also presented. Here, ejection of meteorite material initially is delayed, but finally it leaves the ocean in a cloud of steam and water. The velocities of meteorite material are much lower compared with the continental impact, insufficient to reach large distances on ballistic trajectories. © 2007 Elsevier Ltd. All rights reserved. 2007 10.1016/j.pss.2006.12.002 Planetary and Space Science 55 900-914 Institute of Planetary Research, German Aerospace Center, Rutherford Str. 2, D-12489 Berlin, Germany; Institute of Theoretical Physics, Technical University of Braunschweig, Mendelssohnstr. 3, D-38106 Braunschweig, Germany 7-8 https://www.scopus.com/inward/record.uri?eid=2-s2.0-34247466021&doi=10.1016%2fj.pss.2006.12.002&partnerID=40&md5=36400b0feea59729e17598d5734c9801 cited By 2 D. Niem E. Kührt U. Motschmann conference Rentsch2007797 In this work we present the determination of earthquake locations using an enhanced migration-based location method. We implemented the use of arrival time information into our migration-based location method in order to overcome acquisition geometry pitfalls of a data set from the San Andreas Fault Observatory at Depth (SAFOD). The major aim of this work was to locate the hypocentral region of a repeating earthquake cluster with high precision which is supposed to become the drilling target of the next SAFOD Main Hole drilling phase. Therefore we analysed high quality data from Paulsson Geophysical Services Inc. recorded with an 80 level borehole seismic receiver array deployed in the SAFOD Main Hole. We show step by step the analysis of the data and successful locations of target-earthquakes. 2007 English 9781605601557 69th European Association of Geoscientists and Engineers Conference and Exhibition 2007: Securing The Future. Incorporating SPE EUROPEC 2007 2 Society of Petroleum Engineers 797-801 Berlin Free University Earthquakes; Exhibitions; Location; Seismology; Targets, Acquisition geometries; Arrival times; Data sets; Drilling targets; Earthquake clusters; Earthquake locations; High precisions; High quality datums; Hole drillings; Location methods; Receiver arrays; San andreas faults; Step by steps, Boreholes https://www.scopus.com/inward/record.uri?eid=2-s2.0-55549132278&partnerID=40&md5=a6a7b3fe9f5915cc92ac003d8d3a923a cited By 1 S. Rentsch S. Buske S. Gutjahr J. Kummerow S.A. Shapiro conference Meillieux2007447 We present here an integrated case study of the Lake Bosumtwi impact structure, Ghana, consisting of VSP, geophysical logging, and laboratory measurements on core samples. Bosumtwi crater is 1.07Ma old and has a diameter of 11km, the target rocks being metasediments of 2Ga. The seismic measurements show lower P and S-waves velocities than what is expected in those kinds of rocks. The data are altered by high energy reverberations originating from the air bubble in the water and the steel casing in the sediments. However we obtained velocities between 220 and 350m, going from 2500 to 3000 m/s for the P-wave and from 1000 to 1100 m/s for the S-wave. This indicates a high degree of fracturation and comminution in the hard rock. He-porosity values show a bimodal distribution, with porosities ranging from 1% to 9%, and from 15% to almost 40%. There is a strong linear relationship between porosity and envelope density, but nothing apparent between porosity and grain density or depth. First results with Hg-porosimetry show a bimodal distribution of pore sizes. More samples need to be analyzed in order to draw conclusions on pore structures, but first hypotheses suggest different sizes of crack or the presence of interstitial material depending on rock types and position within the crater. © 2007 Society of Exploration Geophysicists. All rights reserved. Conference paper 2007 English 978-160423897-6 10523812 10.1190/1.2792460 Society of Exploration Geophysicists - 77th SEG International Exposition and Annual Meeting, SEG 2007 26 Society of Exploration Geophysicists 447 – 451 1 Lakes; Pore size; Rocks; Seismic waves; Seismology; Shear waves; Bimodal distribution; Different sizes; Geophysical logging; Impact structures; Interstitial materials; Laboratory measurements; Linear relationships; Seismic measurements; Seismic prospecting https://www.scopus.com/inward/record.uri?eid=2-s2.0-85055678596&partnerID=40&md5=e03580ff15d8a2236a623af145f29089 Cited by: 0 Damien Meillieux Douglas Schmitt Bernd Milkereit Sylvester Danour Kwame Nkrumah article Li200773 2007 English 18168957 10.2204/iodp.sd.s01.09.2007 Scientific Drilling 73-77 Department of Earth Sciences, University of Southern California, 3651 Trousdale Parkway, Los Angeles, Calif. 90089, United States; Division of Earth and Ocean Sciences, Duke University, 109A Old Chemistry Box 90227, Durham, N.C., 27708, United States; Department of Earth and Space Sciences, University of California, 595 Charles Young Drive East, Box 951567, Los Angeles, Calif., 90095-1567, United States 1 SUPPL. 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-72749125134&doi=10.2204%2fiodp.sd.s01.09.2007&partnerID=40&md5=dae4719a0410c9327776ee16441779e1 cited By 4 Y.-G. Li J.E. Vidal article Minyuk2007123 The inorganic geochemistry of sediments from El'gygytgyn Lake shift in phase with interpreted paleoclimatic fluctuations seen in the record over the past 250 ka. Warm periods, when the lake was seasonally ice free and fully mixed, are characterized by increased concentrations of SiO2, CaO, Na2O, K2O, and Rb, by decreased contents of TiO 2, Fe2O3, Al2O3, and MgO, and by a lower chemical index of alteration (CIA). Increased levels of SiO 2 reflect increases in limnic productivity whereas many of the other elements and the CIA likely reflect increased hydrological activity coincident with an increase in coarser sand and silt content and a decrease in clay mineral content. For cold/cooler periods when perennial lake ice cover lead to a stratifed water column and anoxic bottom waters, the opposite is generally observed suggesting a decrease in hydrological activity and an increase in post-depositional chemical alteration. Peaks in P2O3 and MnO, coincident with an increased abundance of vivianite, suggest possible linkages to the paleoproductivity of local fish fauna regardless of climate change across the region surrounding Lake El'gygytgyn. Strontium is high in concentration during warmer intervals and may also be linked to paleoproductivity. Enrichment of the post-Eemian portion of the sediment record in niobium, and yttrium appears independent of glacial-interglacial change; rather it may reflect a gradual shift in the geomorphology of the catchment, particularly the hydrology of large alluvial fans along the western side of the lake. In contrast to some lake records, changes in Zr concentration over time suggests only a weak, if any, increase in eolian sediment supply during colder periods. © 2006 Springer Science+Business Media B.V. 2007 English 09212728 10.1007/s10933-006-9027-4 Journal of Paleolimnology 37 123-133 North-East Interdisciplinary Science Research Institute, FEB RAS, 685000 Magadan, Russian Federation; Department of Geosciences, University of Massachusetts, Amherst, MA 01003, United States; Institute for Geophysics and Geology, University Leipzig, D-04103 Leipzig, Germany 1 chemical alteration; climate change; geochemistry; inorganic compound; lacustrine deposit; paleoclimate; Quaternary; sediment chemistry, Chukchi; Eurasia; Lake El'gygytgyn; Russian Federation https://www.scopus.com/inward/record.uri?eid=2-s2.0-33845948035&doi=10.1007%2fs10933-006-9027-4&partnerID=40&md5=f35aee39d149e013f3c85d536de86c00 cited By 71 P.S. Minyuk J. Brigham-Grette M. Melles V.Ya. Borkhodoev O.Yu. Glushkova article Coney2007667 In 2004, a drilling project by the International Continental Scientific Drilling Program (ICDP) at the Bosumtwi impact crater, Ghana (1.07 Myr old and 10.5 km in diameter), obtained drill core LB-07A, which sampled impactites and underlying metasediments in the crater moat surrounding the small central uplift of the structure. The LB-07A core consists of three sequences: 82.29 m of an upper impactite sequence of alternating polymict lithic and suevitic impact breccias overlying 54.88 m of so-called lower impactite of monomict impact breccia with several suevite intercalations, and 74.53 m of meta-graywacke and altered shale of the basement, also containing a number of suevite intercalations. Major- and trace-element characteristics of all three sequences have been determined to investigate breccia formation and the role of the respective basement lithologies therein. Compositions of polymict impact breccias of the crater fill revealed by core LB-07A are compared with the compositions of the Ivory Coast tektites and the fallout suevites. The impactites of the LB-07A borehole appear well homogenized with respect to the silicate component, and little change in the ranges of many major- and trace-element differences is seen along the length of the borehole (except for Fe2O3, MgO, and CaO contents). Much scatter is observed for a number of elements, and in many cases this increases with depth. It is proposed that any variability in composition is likely the function of clast population differences (i.e., also of relatively small sample sizes). No systematic compositional difference between polymict lithic and suevitic impact breccias is evident. An indication of carbonate enrichment due to hydrothermal alteration is observed in samples from all lithologies. The impactites of the borehole generally show intermediate compositions to previously defined target rocks. The fallout suevites have comparable major element abundances, except for relatively lower MgO contents. The Ivory Coast tektites are generally similar in composition to the LB-07A suevites, but broader ranges in MgO and CaO contents are observed for the LB-07A suevites. © The Meteoritical Society, 2007. Printed in USA. 2007 10.1111/j.1945-5100.2007.tb01067.x Meteoritics and Planetary Science 42 667-688 Impact Cratering Research Group, School of Geosciences, University of the Witwatersrand, Private Bag 3, Johannesburg 2050, South Africa; Museum for Natural History, Department of Mineralogy, Humboldt University Berlin, Invalidenstrasse 43, D-10115 Berlin, Germany; Department of Geological Sciences, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria 4-5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-34250612631&doi=10.1111%2fj.1945-5100.2007.tb01067.x&partnerID=40&md5=d88eb0e070deddf53b50a3f762008eb4 cited By 17 L. Coney W.U. Reimold R.L. Gibson C. Koeberl article Janský2007199 We determine the velocities in an upper crustal model, composed of three homogeneous layers, for one subregion of the western part of the Gulf of Corinth, NE of the town of Aigion, Greece. We have used local events that occurred there in the year 2001 and were recorded by the Corinth Rift Laboratory Network. Weighted P and S arrival time residuals are minimized using the Neighbourhood Algorithm of Sambridge (1999), combined with the grid search for source locations. The resolution of the inversion is tested by delete-one jackknifing. The model obtained is compared with some other models derived or applied to the subregion. A fast velocity increase between depths of 5 and 7 km is confirmed as the major structural element. © Springer Science+Business Media, Inc. 2007. Article 2007 English 13834649 10.1007/s10950-007-9047-1 Journal of Seismology 11 199 – 204 2 Gulf of Corinth; Ionian Sea; Mediterranean Sea; algorithm; arrival time; crustal structure; data inversion; P-wave; S-wave; seismic velocity; upper crust https://www.scopus.com/inward/record.uri?eid=2-s2.0-33947693273&doi=10.1007%2fs10950-007-9047-1&partnerID=40&md5=917f7e108064b80619c7bb82dbaab729 Cited by: 2 Jaromír Janský Vladimír Plicka Hélène Lyon-Caen Oldřich Novotny article Schmitt2007755 In order to assist in the interpretation of previous seismic refraction and reflection surveys, a vertical seismic profile was acquired in the Lake Bosumtwi (Ghana) hard-rock core hole LB-08A. No seismic reflections are seen in the up-going wave field obtained, and this observation is consistent with the lack of reflectivity observed in the corresponding 2-D surface seismic profile obtained in earlier studies. Direct down-going P-waves were found both in the cased sediment column from a depth of 73 m to 239 m below the lake surface and in the open-hole "hard rock" section from a depth of 239 m to 451 m of LB-08A. Analysis of the observed travel times indicates a nearly constant P-wave velocity of 1520 m/s through the soft lacustrine sediments. In the hard-rock, however, the P-wave velocity rapidly increases by nearly 30% from 2600 m/s to 3340 m/s. These values are in good agreement with the gross velocity structure obtained in the earlier joint inversion of seismic reflection and refraction data. These values are low relative to those expected for the metasedimentary protoliths, an observation that has been made at other young impact structures of similar size. The low velocities, together with the fact that they increase so rapidly, is suggestive of a decreasing density of fractures and microcracks with depth. Consequently, the seismic velocity trend may provide a proxy measure of damage, and hence, the decay of the shock pressure from the impact point. Validation of this requires additional detailed studies of the porosity structure in the core. © The Meteoritical Society, 2007. Printed in USA. Article 2007 English 10869379 10.1111/j.1945-5100.2007.tb01072.x Meteoritics and Planetary Science 42 University of Arkansas 755 – 768 4-5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-34250680541&doi=10.1111%2fj.1945-5100.2007.tb01072.x&partnerID=40&md5=098dc7541b8156cecf70bf34dbd26631 Cited by: 18 Doug R. Schmitt Bernd Milkereit Tobias Karp Christopher Scholz Sylvester Danuor D. Meillieux M. Welz article Vylita2007427 The first set of U-series ages of the hot-spring travertine from the world-famous Karlovy Vary Spa indicates repeated growth of the travertine accumulation followed by its erosion by the Teplá River. The obtained data are important as an estimate of minimum duration of thermal water circulation in Karlovy Vary and in understanding of the river valley evolution during the youngest geological history. The oldest 230Th/ 234U age data (230 ± 14 ka BP and 155 ± 7 ka BP) have been obtained for travertine relicts located 22 m above the present-day bottom of the valley. The extensive travertine accumulation located directly on the valley bottom was formed by gradual growth, particularly during the first half of the Weichselian period, between 100 and 50 ka BP. These data show that the valley bottom was at approximately the same elevation as it is today already during the Eemian interglacial. At the end of the Weichselian the central part of the travertine accumulation was downcut by river erosion. During Holocene the new deposition of travertine was concentrated in this wide trench, being likely repeatedly modified by river activity. The travertine accumulation started to be strongly influenced by humans since the Middle Ages. A significant part of it was quarried out for lime production. The accumulation was later covered by buildings, streets and the reinforced course of the Teplá River. © 2007 Gebrüder Borntraeger. Article 2007 English 03728854 10.1127/0372-8854/2007/0051-0427 Zeitschrift fur Geomorphologie 51 Schweizerbart Science Publishers 427 – 442 4 Central Europe; Czech Republic; Eurasia; Europe; Karlovarsky; Karlovy Vary; Tepla River; concentration (composition); dating method; Eemian; geochronology; Holocene; interglacial; landform evolution; thermal evolution; thermal spring; travertine https://www.scopus.com/inward/record.uri?eid=2-s2.0-38149108203&doi=10.1127%2f0372-8854%2f2007%2f0051-0427&partnerID=40&md5=1d27a61705c4332ffaaf73be58fa26f5 Cited by: 24 Tomáš Vylita Karel Žák Václav Cílek Helena Hercman Lucie Mikšíková book Ivanov2007207 To use the information about impact craters on terrestrial planets for study of planetary geology and geophysics, one should combine a wide set of processes and parameters. The chapter presents a review of impact cratering processes, estimates of average impact velocities, and impact probability for terrestrial planets. Basics of the impact crater scaling is discussed to present to date level of confidence in problems, where one needs to correlate measured size of an impact crater and mass and size of a body, created the impact structure. Scaling laws for large impact crates are discussed in comparison with results of the direct numerical modeling of impact cratering. The accumulation rate for impact craters on terrestrial planets is believed to be constant (within a factor of 2) during the last ∼3 Ga of the solar system history. Measuring the number of accumulated craters of a given size in the area of interest, one can estimate relative age of the visible surface, provided the older surfaces accumulate larger number of craters. In connection with this technique measured size-frequency distribution of impact craters is discussed, including the now widely disputable topic of secondary cratering, preventing the simple interpretation of cratering record for small craters. © 2007 Elsevier B.V. All rights reserved. 2007 10.1016/B978-044452748-6.00158-9 Treatise on Geophysics 10 207-242 Institute for Dynamics of Geospheres, Moscow, Russian Federation; Planetary Science Institute, Tucson AZ, United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-61849115344&doi=10.1016%2fB978-044452748-6.00158-9&partnerID=40&md5=82b1fc1d827959e7cb976afde09568fa cited By 29 B.A. Ivanov W.K. Hartmann article Schleicher200768 2007 English 18168957 10.2204/iodp.sd.s01.33.2007 Scientific Drilling 68-70 Universität Würzburg, Geologisches Institut, Pleicherwall 1, 97070 Würzburg, Germany; University of Michigan, Department of Geological Sciences, 1100 University Avenue, C.C.Little Building, Ann Arbor, Mich. 48109, United States; Centre de Géochimie de la Surface (CNRS-ULP), 1 rue Blessig, 67084 Strasbourg, France; U.S. Geological Survey, Earthquake Hazards Team, 345 Middlefield Road, MS 977 Menlo Park, Calif. 94025, United States 1 SUPPL. 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-78651579355&doi=10.2204%2fiodp.sd.s01.33.2007&partnerID=40&md5=57e75aaf81c4a0d33226278cf47ea6dc cited By 2 A.M. Schleicher B.A. Pluijm L.N. Warr J.G. Solum article McGrail2007 Resonant ultrasound spectroscopy was used to characterize a natural geological core sample obtained from the Mallik 5L-38 gas hydrate research well at high pressure and subambient temperatures. Using deuterated methane gas to form gas hydrate in the core sample, it was discovered that resonance amplitudes are correlated with the fraction of the pore space occupied by the gas hydrate crystals. A pore water freezing model was developed that utilizes the known pore size distribution and pore water chemistry to predict gas hydrate saturation as a function of pressure and temperature. The model showed good agreement with the experimental measurements and demonstrated that pore water chemistry is the most important factor controlling equilibrium gas hydrate saturations in these sediments when gas hydrates are formed artificially in laboratory pressure vessels. With further development, the resonant ultrasound technique can provide a rapid, nondestructive, field portable means of measuring the equilibrium P-T properties and dissociation kinetics of gas hydrates in porous media, determining gas hydrate saturations, and may provide new insights into the nature of gas hydrate formation mechanisms in geologic materials. Copyright 2007 by the American Geophysical Union. 2007 English 21699313 10.1029/2005JB004084 Journal of Geophysical Research: Solid Earth 112 Blackwell Publishing Ltd Applied Geology and Geochemistry Department, Pacific Northwest National Laboratory, Richland, WA, United States; Applied Physics and Materials Characterization Department, Pacific Northwest National Laboratory, Richland, WA, United States; Petroleum Engineering Department, University of Alaska, Fairbanks, AK, United States; Applied Physics and Materials Characterization Department, Pacific Northwest National Laboratory, P. O. Box 999, Richland, WA 99352, United States; Applied Geology and Geochemistry Department, Pacific Northwest National Laboratory, P. O. Box 999, Richland, WA 99352, United States; Petroleum Engineering Department, University of Alaska, 411 Duckering Building, Fairbanks, AK 99775, United States 5 core analysis; equilibrium; gas hydrate; laboratory method; measurement method; pore space; porewater; porous medium; resonance; saturation; spectroscopy https://www.scopus.com/inward/record.uri?eid=2-s2.0-65349132403&doi=10.1029%2f2005JB004084&partnerID=40&md5=968aa9e186b76e43ae222d81e1cce597 cited By 2 B.P. McGrail S. Ahmed H.T. Schaef A.T. Owen P.F. Martin T. Zhu article Coney2007667 In 2004, a drilling project by the International Continental Scientific Drilling Program (ICDP) at the Bosumtwi impact crater, Ghana (1.07 Myr old and 10.5 km in diameter), obtained drill core LB-07A, which sampled impactites and underlying metasediments in the crater moat surrounding the small central uplift of the structure. The LB-07A core consists of three sequences: 82.29 m of an upper impactite sequence of alternating polymict lithic and suevitic impact breccias overlying 54.88 m of so-called lower impactite of monomict impact breccia with several suevite intercalations, and 74.53 m of meta-graywacke and altered shale of the basement, also containing a number of suevite intercalations. Major- and trace-element characteristics of all three sequences have been determined to investigate breccia formation and the role of the respective basement lithologies therein. Compositions of polymict impact breccias of the crater fill revealed by core LB-07A are compared with the compositions of the Ivory Coast tektites and the fallout suevites. The impactites of the LB-07A borehole appear well homogenized with respect to the silicate component, and little change in the ranges of many major- and trace-element differences is seen along the length of the borehole (except for Fe2O3, MgO, and CaO contents). Much scatter is observed for a number of elements, and in many cases this increases with depth. It is proposed that any variability in composition is likely the function of clast population differences (i.e., also of relatively small sample sizes). No systematic compositional difference between polymict lithic and suevitic impact breccias is evident. An indication of carbonate enrichment due to hydrothermal alteration is observed in samples from all lithologies. The impactites of the borehole generally show intermediate compositions to previously defined target rocks. The fallout suevites have comparable major element abundances, except for relatively lower MgO contents. The Ivory Coast tektites are generally similar in composition to the LB-07A suevites, but broader ranges in MgO and CaO contents are observed for the LB-07A suevites. © The Meteoritical Society, 2007. Printed in USA. Article 2007 English 10869379 10.1111/j.1945-5100.2007.tb01067.x Meteoritics and Planetary Science 42 University of Arkansas 667 – 688 4-5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-34250612631&doi=10.1111%2fj.1945-5100.2007.tb01067.x&partnerID=40&md5=d88eb0e070deddf53b50a3f762008eb4 Cited by: 17 Louise Coney Wolf Uwe Reimold Roger L. Gibson Christian Koeberl article Chen2007243 In order to understand the fault zone architecture and mechanisms that caused the Chi-Chi earthquake, the Chelungpu drilling project was conducted during April 2000 through a collaborative project between Japan and Taiwan. In this study, chemical and mineralogical variations within the overall Chelungpu fault zone, including variations between less damaged host rocks, damaged zones, and fault cores caused by the Chi-Chi earthquake were examined. Slopes of TiO2 immobile isocons were consistently &gt; 1 for analyses comparing host rocks with rocks from damaged zones or with gouges from fault cores, indicating that volume loss occurred in damaged zones and the fault cores. These results strongly imply that pervasive fluid infiltration occurred within the fault zone. Volume loss within the damaged zone and fault core is interpreted to result from a two-stage process involving: (i) coseismic mechanical wearing and/or dissolution in the fault core, and (ii) fluid infiltration within the fault zone during postseismic and interseismic periods along cracks caused by seismic failure. Semi-quantitative XRD analysis indicates that the kaolinite content consistently increases from the less damaged host rocks to the damaged zone and gouges in each fault core. Mineralogic changes indicate that pervasive acidic fluid infiltration occurred within the fault zones and reacted with the feldspars or muscovite to form kaolinite. Enrichment of kaolinite and illite found in the fault zones of southern drilling site could play some role on the slipping behavior of the southern part of the Chelungpu fault. Greater volume loss in the fault core may have resulted from moderate permeability, combined with the very fine grain nature of pulverized material in the fault core, which enhanced chemical reactions including transformation of feldspars and muscovite to clay minerals. The study results indicate that pervasive fluid infiltration occurred and changed the mineralogical and chemical architecture of fault zones caused by the cyclic earthquakes. © 2007 Elsevier B.V. All rights reserved. 2007 English 00401951 10.1016/j.tecto.2007.01.025 Tectonophysics 443 243-254 Department of Earth Sciences, National Central University, Taiwan; Department of Earth and Planet. Sciences, University of Tokyo, Japan; Institute of Applied Geology, National Central University, Taiwan; Department of Geosciences, National Taiwan University, Taiwan 3-4 active fault; chemical composition; Chi-Chi earthquake 1999; core analysis; fault zone; mineralogy, Asia; Eurasia; Far East; Taiwan https://www.scopus.com/inward/record.uri?eid=2-s2.0-34648834432&doi=10.1016%2fj.tecto.2007.01.025&partnerID=40&md5=703d38bd828e7df5aeb2d321aaec95a4 cited By 21 W.-m.D. Chen H. Tanaka H.-j. Huang C.-b. Lu C.-y. Lee C.-Y. Wang article Tomaru2007656 The authors report here halogen concentrations in pore waters and sediments collected from the Mallik 5L-38 gas hydrate production research well, a permafrost location in the Mackenzie Delta, Northwest Territories, Canada. Iodine and Br are commonly enriched in waters associated with CH4, reflecting the close association between these halogens and source organic materials. Pore waters collected from the Mallik well show I enrichment, by one order of magnitude above that of seawater, particularly in sandy layers below the gas hydrate stability zone (GHSZ). Although Cl and Br concentrations increase with depth similar to the I profile, they remain below seawater values. The increase in I concentrations observed below the GHSZ suggests that I-rich fluids responsible for the accumulation of CH4 in gas hydrates are preferentially transported through the sandy permeable layers below the GHSZ. The Br and I concentrations and I/Br ratios in Mallik are considerably lower than those in marine gas hydrate locations, demonstrating a terrestrial nature for the organic materials responsible for the CH4 at the Mallik site. Halogen systematics in Mallik suggest that they are the result of mixing between seawater, freshwater and an I-rich source fluid. The comparison between I/Br ratios in pore waters and sediments speaks against the origin of the source fluids within the host formations of gas hydrates, a finding compatible with the results from a limited set of 129I/I ratios determined in pore waters, which gives a minimum age of 29 Ma for the source material, i.e. at the lower end of the age range of the host formations. The likely scenario for the gas hydrate formation in Mallik is the derivation of CH4 together with I from the terrestrial source materials in formations other than the host layers through sandy permeable layers into the present gas hydrate zones. © 2006 Elsevier Ltd. All rights reserved. 2007 English 08832927 10.1016/j.apgeochem.2006.12.013 Applied Geochemistry 22 656-675 Department of Earth and Environmental Sciences, University of Rochester, Rochester, NY 14627, United States; Department of Earth and Planetary Science, University of Tokyo, Tokyo, 113-0033, Japan 3 Earth atmosphere; Gas hydrates; Natural gas wells; Seawater; Sedimentology, Gas hydrate production; Gas hydrate stability zone (GHSZ); Halogen systematics; Pore waters, Halogen compounds, bromine; coastal sediment; enrichment; gas hydrate; iodine; methane; mixing; organic matter; permafrost; porewater; seawater, Canada; Mackenzie Delta; North America; Northwest Territories https://www.scopus.com/inward/record.uri?eid=2-s2.0-33847332547&doi=10.1016%2fj.apgeochem.2006.12.013&partnerID=40&md5=95bf922761b1217ee1658df8cef9ae05 cited By 27 H. Tomaru U. Fehn Z. Lu R. Matsumoto article LHeureux2007849 The recent drilling of the Bosumtwi impact structure, Ghana, has provided a unique opportunity to study the petrophysical properties of a young, well-preserved impact crater. The damage induced by impact results in extensive fracturing and mixing of target materials. We discuss here a means of using sonic velocity and density logs from two boreholes through the Bosumtwi crater fill and basement to estimate the degree of heterogeneity and fracturing within the impacted target, in order to understand the discrepancy between the large impedances derived from the log data and the nonreflective zone of impactites observed in seismic sections. Based on an analysis of the stochastic fluctuations in the log data, the Bosumtwi impactites are characterized by vertical scale lengths of 2-3 m. From the resolution of the seismic data over the crater, horizontal scale lengths are estimated at <12 m. The impactites therefore fall within the quasi-homogeneous scattering regime, i.e., seismic energy will propagate through the medium with little disruption. Scale lengths as small as these are observed in the fractured basement rocks of impact structures, whereas non-impact related crystalline environments are characterized by scale lengths an order of magnitude larger. Assuming that the high-frequency fluctuations observed in the log data are more sensitive to fracture distribution than petrology, this suggests that the small scale lengths observed within impact structures are characteristic of impact-induced damage, and could be used to estimate the extent of fracturing undergone by the rocks at any depth below an impact structure. © The Meteoritical Society, 2007. Printed in USA. Article 2007 English 10869379 10.1111/j.1945-5100.2007.tb01080.x Meteoritics and Planetary Science 42 University of Arkansas 849 – 858 4-5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-34250625239&doi=10.1111%2fj.1945-5100.2007.tb01080.x&partnerID=40&md5=c14ff69edf2abd6e684a31abf7bb1c82 Cited by: 5; All Open Access, Bronze Open Access Elizabeth L'Heureux Bernd Milkereit article Petersen2007655 Drill-core samples from the Bosumtwi impact structure (1.07 Myr old and 10.5 km in diameter) in Ghana exhibit mineralogical evidence for post-impact hydrothermal alteration. Nine samples of drill core obtained through the 2004 International Continental Scientific Drilling Project (ICDP) were studied, including an uppermost fallback layer overlying impactite breccias, and partly deformed massive meta-graywacke bedrock. The petrographic study revealed alteration veins containing secondary sericitic muscovite (comparable to 2M1-muscovite) crosscutting original bedding in meta-graywacke and forming a matrix between clasts in impactite breccias. X-ray diffraction (XRD) shows that these impactite samples are rich in 2M1-muscovite, consistent with post-impact fluid deposition and alteration. Optical analysis indicates the presence of a pre-impact stratiform chlorite in meta-graywacke samples and a secondary alteration chlorite occurring in all samples. Secondary illite was detected in upper impactites of drill core LB-08A and samples containing accretionary lapilli. The lower temperature constraint for the hydrothermal event is given by 2M1-muscovite, secondary chlorite, and illite, all of which form at temperatures greater than 280 °C. An absence of recrystallization of quartz and feldspar indicates an upper temperature constraint below 900 °C. The presence of alteration materials associated with fractures and veins in the uppermost impactites of drill cores LB-07A and LB-08A indicates that a post-impact hydrothermal system was present in and adjacent to the central uplift portion of the Bosumtwi impact structure. A sample containing accretionary lapilli obtained from drill core LB-05A exhibits limited evidence that hydrothermal processes were more widespread within the impactites on the crater floor. © The Meteoritical Society, 2007. Printed in USA. 2007 10.1111/j.1945-5100.2007.tb01066.x Meteoritics and Planetary Science 42 655-666 Institute of Meteoritics, University of New Mexico, Albuquerque, NM 87131, United States; Department of Earth and Planetary Sciences, University of New Mexico, Albuquerque, NM 87131, United States 4-5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-34250666647&doi=10.1111%2fj.1945-5100.2007.tb01066.x&partnerID=40&md5=e3ee7ec17b4aa211974e2983ae696398 cited By 8 M.T. Petersen H.E. Newsom M.J. Nelson D.M. Moore article Petersen2007655 Drill-core samples from the Bosumtwi impact structure (1.07 Myr old and 10.5 km in diameter) in Ghana exhibit mineralogical evidence for post-impact hydrothermal alteration. Nine samples of drill core obtained through the 2004 International Continental Scientific Drilling Project (ICDP) were studied, including an uppermost fallback layer overlying impactite breccias, and partly deformed massive meta-graywacke bedrock. The petrographic study revealed alteration veins containing secondary sericitic muscovite (comparable to 2M1-muscovite) crosscutting original bedding in meta-graywacke and forming a matrix between clasts in impactite breccias. X-ray diffraction (XRD) shows that these impactite samples are rich in 2M1-muscovite, consistent with post-impact fluid deposition and alteration. Optical analysis indicates the presence of a pre-impact stratiform chlorite in meta-graywacke samples and a secondary alteration chlorite occurring in all samples. Secondary illite was detected in upper impactites of drill core LB-08A and samples containing accretionary lapilli. The lower temperature constraint for the hydrothermal event is given by 2M1-muscovite, secondary chlorite, and illite, all of which form at temperatures greater than 280 °C. An absence of recrystallization of quartz and feldspar indicates an upper temperature constraint below 900 °C. The presence of alteration materials associated with fractures and veins in the uppermost impactites of drill cores LB-07A and LB-08A indicates that a post-impact hydrothermal system was present in and adjacent to the central uplift portion of the Bosumtwi impact structure. A sample containing accretionary lapilli obtained from drill core LB-05A exhibits limited evidence that hydrothermal processes were more widespread within the impactites on the crater floor. © The Meteoritical Society, 2007. Printed in USA. Article 2007 English 10869379 10.1111/j.1945-5100.2007.tb01066.x Meteoritics and Planetary Science 42 University of Arkansas 655 – 666 4-5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-34250666647&doi=10.1111%2fj.1945-5100.2007.tb01066.x&partnerID=40&md5=e3ee7ec17b4aa211974e2983ae696398 Cited by: 8; All Open Access, Bronze Open Access Michael T. Petersen Horton E. Newsom Melissa J. Nelson Duane M. Moore article Pati200781 Impact cratering is a geological process characterized by ultra-fast strain rates, which generates extreme shock pressure and shock temperature conditions on and just below planetary surfaces. Despite initial skepticism, this catastrophic process has now been widely accepted by geoscientists with respect to its importance in terrestrial - indeed, in planetary - evolution. About 175 impact structures have been discovered on Earth so far, and some more structures are considered to be of possible impact origin. One major extinction event, at the Cretaceous-Paleogene boundary, has been firmly linked with catastrophic impact, but whether other important extinction events in Earth history, including the so-called "Mother of All Mass Extinctions" at the Permian-Triassic boundary, were triggered by huge impact catastrophes is still hotly debated and a subject of ongoing research. There is a beneficial side to impact events as well, as some impact structures worldwide have been shown to contain significant (in some cases, world class) ore deposits, including the gold-uranium province of the Witwatersrand basin in South Africa, the enormous Ni and PGE deposits of the Sudbury structure in Canada, as well as important hydrocarbon resources, especially in North America. Impact cratering is not a process of the past, and it is mandatory to improve knowledge of the past-impact record on Earth to better constrain the probability of such events in the future. In addition, further improvement of our understanding of the physico-chemical and geological processes fundamental to the impact cratering process is required for reliable numerical modeling of the process, and also for the correlation of impact magnitude and environmental effects. Over the last few decades, impact cratering has steadily grown into an integrated discipline comprising most disciplines of the geosciences as well as planetary science, which has created positive spin-offs including the study of paleo-environments and paleo-climatology, or the important issue of life in extreme environments. And yet, in many parts of the world, the impact process is not yet part of the geoscience curriculum, and for this reason, it deserves to be actively promoted not only as a geoscientific discipline in its own right, but also as an important life-science discipline. 2007 10.1007/s12040-007-0009-3 Journal of Earth System Science 116 81-98 Department of Earth and Planetary Sciences, Nehru Science Centre, University of Allahabad, Allahabad 211 002, India; Museum f. Natural History (Mineralogy), Humboldt-University in Berlin, Invalidenstrasse 43, D-10115 Berlin, Germany 2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-34247367579&doi=10.1007%2fs12040-007-0009-3&partnerID=40&md5=22769c24efd84e321553edd29fa7f4c3 cited By 22 J.K. Pati W.U. Reimold article Osinski20071 Despite being present in the target sequence of ∼70% of the world's known impact structures, the response of sedimentary rocks to hypervelocity impact remains poorly understood. Of particular significance is the relative importance and role of impact melting versus decomposition in carbonate and sulfate lithologies. In this work, we review experimental evidence and phase equilibria and synthesize these data with observations from studies of naturally shocked rocks from several terrestrial impact sites. Shock experiments on carbonates and sulfates currently provide contrasting and ambiguous results. Studies of naturally shocked materials indicate that impact melting is much more common in sedimentary rocks than previously thought. This is in agreement with the phase relations for calcite. A summary of the criteria for the recognition of impact melts derived from sedimentary rocks is presented, and it is hoped that this will stimulate further studies of impact structures in sedimentary target rocks. This assessment leads us to conclude that impact melting is common during hypervelocity impact into both crystalline and sedimentary rocks. However, the products are texturally and chemically distinct, which has led to much confusion in the past, particularly in terms of the recognition of impact melts derived from sedimentary rocks. © 2008 The Geological Society of America. All rights reserved. 2007 10.1130/2008.2437(01) Special Paper of the Geological Society of America 437 1-18 Department of Earth Sciences/Physics and Astronomy, University of Western Ontario, London, ON N6A 5B7, Canada; Planetary and Space Science Centre, Department of Geology, University of New Brunswick, 2 Bailey Drive, Fredericton, NB E3B 5A3, Canada; Earth Sciences Sector, Natural Resources Canada, Ottawa, ON K1A 0E4, Canada https://www.scopus.com/inward/record.uri?eid=2-s2.0-75749106193&doi=10.1130%2f2008.2437%2801%29&partnerID=40&md5=171f0209e8e261b9b240cc1b5933c7c1 cited By 41 G.R. Osinski J.G. Spray R.A.F. Grieve article Bellefleur2007 Wave attenuation is an important physical property of hydrate-bearing sediments that is rarely taken into account in site characterization with seismic data. We present a field example showing improved images of hydrate-bearing sediments on seismic data after compensation of attenuation effects. Compressional quality factors estimated from zero-offset Vertical Seismic Profiling data acquired at Mallik, Northwest Territories, Canada, demonstrate significant wave attenuation for hydrate-bearing sediments. These results are in agreement with previous attenuation estimates obtained from sonic logs and crosshole data at different frequency intervals. The application of an inverse Q-filter to compensate attenuation effects of permafrost and hydrate-bearing sediments improved the resolution of surface 3D seismic data and its correlation with log data, particularly for the shallowest gas hydrate interval. Compensation of the attenuation effects of the permafrost likely explains most of the improvements for the shallow gas hydrate zone. Our results show that characterization of the Mallik gas hydrates with seismic data not corrected for attenuation would tend to overestimate thicknesses and lateral extent of hydrate-bearing strata and hence, the volume of hydrates in place. Copyright 2007 by the American Geophysical Union. 2007 English 21699313 10.1029/2007JB004976 Journal of Geophysical Research: Solid Earth 112 Blackwell Publishing Ltd Geological Survey of Canada, 615 Booth Street, Ottawa, ON K1A 0E9, Canada; McGill University, Department of Earth and Planetary Sciences, Montréal, QC H3A 2A7, Canada; Geological Survey of Canada, 3303 - 33 St. N-W, Calgary, AB T2L 2A7, Canada; Geological Survey of Canada, P. O. Box 6000, Sidney, BC V8L 4B2, Canada 10 gas hydrate; permafrost; seismic attenuation; seismic data, Canada; Mackenzie Delta; North America; Northwest Territories https://www.scopus.com/inward/record.uri?eid=2-s2.0-37349004549&doi=10.1029%2f2007JB004976&partnerID=40&md5=c2ec695d8628f53e07777c76c491f835 cited By 37 G. Bellefleur M. Riedel T. Brent F. Wright S.R. Dallimore article Boamah20061761 Field studies and a shallow drilling program carried out in 1999 provided information about thickness and distribution of suevite to the north of the Bosumtwi crater rim. Suevite occurrence there is known from an ∼1.5 km2 area; its thickness is ≤15 m. The present suevite distribution is likely the result of differential erosion and does not reflect the initial areal extent of continuous Bosumtwi ejecta deposits. Here we discuss the petrographic characteristics of drill core samples of melt-rich suevite. Macroscopic constituents of the suevites are melt bodies and crystalline and metasedimentary rock (granite, graywacke, phyllite, shale, schist, and possibly slate) clasts up to about 40 cm in size. Shock metamorphic effects in the clasts include multiple sets of planar deformation features (PDFs), diaplectic quartz and feldspar glasses, lechatelierite, and ballen quartz, besides biotite with kink bands. Basement rock clasts in the suevite represent all stages of shock metamorphism, ranging from samples without shock effects to completely shock-melted material that is indicative of shock pressures up to ∼60 GPa. © The Meteoritical Society, 2006. Article 2006 English 10869379 10.1111/j.1945-5100.2006.tb00450.x Meteoritics and Planetary Science 41 University of Arkansas 1761 – 1774 11 Africa; Ghana; Sub-Saharan Africa; West Africa; crater; crystalline rock; ejecta; fallout; impact structure; metasedimentary rock; suevite https://www.scopus.com/inward/record.uri?eid=2-s2.0-33751354610&doi=10.1111%2fj.1945-5100.2006.tb00450.x&partnerID=40&md5=81fff0917c487cd736818e9b033394a4 Cited by: 25 Daniel Boamah Christian Koeberl article Herzberg2006605 There is uncertainty about whether the abundant tholeiitic lavas on Hawaii are the product of melt from peridotite or pyroxenite/eclogite rocks. Using a parameterization of melting experiments on peridotite with glass analyses from the Hawaii Scientific Deep Project 2 on Mauna Kea volcano, I show here that a small population of the core samples had fractionated from a peridotite-source primary magma. Most lavas, however, differentiated from magmas that were too deficient in CaO and enriched in NiO (ref. 2) to have formed from a peridotite source. For these, experiments indicate that they were produced by the melting of garnet pyroxenite, a lithology that had formed in a second stage by reaction of peridotite with partial melts of subducted oceanic crust. Samples in the Hawaiian core are therefore consistent with previous suggestions that pyroxenite occurs in a host peridotite, and both contribute to melt production. Primary magma compositions vary down the drill core, and these reveal evidence for temperature variations within the underlying mantle plume. Mauna Kea magmatism is represented in other Hawaiian volcanoes, and provides a key for a general understanding of melt production in lithologically heterogeneous mantle. ©2006 Nature Publishing Group. 2006 English 00280836 10.1038/nature05254 Nature 444 Nature Publishing Group 605-609 Department of Geological Sciences, Rutgers University, Piscataway, NJ 08854, United States 7119 Lithology; Melting; Rocks; Thermal plumes; Uncertain systems; Volcanoes, Hawaiian core; Mauna Kea magmatism; Pyroxenite/eclogite rocks; Tholeiitic lavas, Petrology, aluminum derivative; aluminum trioxide; calcium oxide; chromium trioxide; dipotassium oxide; glass; iron oxide; iron trioxide; magnesium oxide; manganese oxide; nitrogen oxide; oxacillin; oxide; phosphorus pentoxide; potassium derivative; silicon dioxide; titanium dioxide, core analysis; lava; magma; mantle plume; oceanic crust; peridotite; petrology; pyroxenite; thermal structure; tholeiite, article; calibration; crystallization; fractionation; garnet; melting point; peridotite; petrology; priority journal; pyroxenite; rock; volcano https://www.scopus.com/inward/record.uri?eid=2-s2.0-33845257871&doi=10.1038%2fnature05254&partnerID=40&md5=cd5e1c7a0245f32daaf1e89426bf67d1 cited By 220 C. Herzberg article Lefticariu200651 The Chicxulub Sedimentary Basin of the northwestern Yucatan Peninsula, Mexico, which was formed because of the largest identified Phanerozoic bolide impact on Earth, became a site of deposition of dominantly marine carbonate sediments during most of the Cenozoic Era. This is a study of the filling and diagenetic history of this basin and surrounding areas. The study makes use of lithologic, biostratigraphic, petrographic, and geochemical data obtained on core samples from boreholes drilled throughout the northwestern Yucatan Peninsula. The core sample data indicate that: 1) The Chicxulub Sedimentary Basin concentrated the deposition of pelagic and outer-platform sediments during the Paleocene and Eocene, and, in places, during the Early Oligocene, as well, and filled during the Middle Miocene, 2) deeper-water limestone also is present within the Paleocene and Lower Eocene of the proposed Santa Elena Depression, which is located immediately south of the Basin, 3) shallow-water deposits are relatively more abundant outside the Basin and Depression than inside, 4) the autigenic and allogenic silicates from the Paleogene formations are the most abundant inside the Depression, 5) sediment deposition and diagenesis within the Basin also were controlled by impact crater topography, 6) the abundance of the possible features of subaerial exposure increases upward and outward from the center of the Basin, and 7) the formation of replacive low-magnesium calcite and dolomite, dedolomitization, dissolution, and precipitation of vug-filling calcite and dolomite cement have been more common outside the Basin than inside. δ18O in whole-rock (excluding vug-filling) calcite from core samples ranges from -7.14‰ to + 0.85‰ PDB. δ13C varies from -6.92‰ to +3.30‰ PDB. Both stable isotopes correlate inversely with the abundance of subaerial exposure features indicating that freshwater diagenesis has been extensive especially outside and at the edge of the Chicxulub Sedimentary Basin. δ18O and δ13C in w hole-rock (excluding vug-filling) dolomite ranges from -5.54‰ to +0.87‰ PDB and -4.63‰ to +3.38‰ PDB, respectively. Most dolomite samples have negative δ18O and positive δ13C suggesting that replacive dolomitization involved the presence of a fluid dominated by freshwater and/or an anomalously high geothermal gradient. Most dolomite XRD-determined mole percent CaCO3 varies between 51 and 56. Replacive dolomite is larger, more euhedral, and less stoichiometric inside the Chicxulub Sedimentary Basin than outside. © 2005 Elsevier B.V. All rights reserved. 2006 10.1016/j.sedgeo.2005.09.008 Sedimentary Geology 183 51-69 Northern Illinois University, Department of Geology and Environmental Geosciences, DeKalb, IL 60115, United States; University of New Orleans, Department of Geology and Geophysics, New Orleans, LA 70148, United States; Indiana University Bloomington, Department of Geological Sciences, Bloomington, IN 47405, United States; TTL Associates Inc., 1916 N12th Street, Toledo, OH 43624, United States 1-2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-29844451829&doi=10.1016%2fj.sedgeo.2005.09.008&partnerID=40&md5=44cc05603534b7db962fc79736335c6c cited By 25 M. Lefticariu E.C. Perry W.C. Ward L. Lefticariu article Martinez-Ruiz20061 The Chicxulub impact event led to a worldwide deposition of impact materials originated from target rocks and the vaporized bolide. Relative contributions of both types of material to the K/T ejecta deposits vary with distance to the crater site. At distal sites (e.g., Agost and Caravaca in the SE of Spain) a major contribution of extraterrestrial material is indicated by different impact signatures, such as Os and Cr isotope composition, abundant microkrystites, platinum group elements and other siderophile elements that are typical of extraterrestrial components. Closer settings to the Chicxulub crater, for example the Blake Nose Plateau in the North American margin, display major continental crustal rock contributions in the ejecta layer. REE compositions provide additional evidence for terrestrial vs. extraterrestrial rock contributions. Previous research has not focused specifically on REE concentrations and corresponding C1- and NASC-normalized patterns. However, normalized REE patterns are already generating supplementary insights into the nature of the original material of the K/T boundary layer. Thus, Blake Nose ejecta C1-normalized patterns indicate a derivation from continental crustal target rocks. In more distal sections REE compositions point to a probable mafic precursor and confirm that extraterrestrial materials represent a major contribution the ejecta layer. © 2006 Elsevier B.V. All rights reserved. 2006 10.1016/j.chemgeo.2006.02.013 Chemical Geology 232 1-11 Instituto Andaluz de Ciencias de la Tierra, CSIC - Universidad de Granada, Facultad de Ciencias, Avda. Fuentenueva, s/n, 18002 Granada, Spain; Departamento de Mineralogía y Petrología, Facultad de Ciencias, Universidad de Granada, Avda. Fuentenueva, s/n, 18002 Granada, Spain; Centro Andaluz de Medio Ambiente (CEAMA), Junta de Andalucía - Universidad de Granada, Avda. del Mediterráneo, s/n, 18006 Granada, Spain 1-2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-33746415305&doi=10.1016%2fj.chemgeo.2006.02.013&partnerID=40&md5=86cae94e481c26ba05cf75e658a1bc73 cited By 16 F. Martínez-Ruiz M. Ortega-Huertas P. Rivas article Mark:2006:1816-8957:32 SAFOD, the San Andreas Fault Observatory at Depth (Fig. 1), completed an important milestone in July 2005 by drilling through the San Andreas Fault at seismogenic depth. SAFOD is one of three major components of EarthScope, a U.S. National Science Foundation (NSF) initiative being conducted in collaboration with the U.S. Geological Survey (USGS). The International Continental Scientific DrillingProgram (ICDP) provides engineering and technical support for the project as well as online access to project data and information (https://www.icdp-online.org/sites/sanandreas/news/news1.html). In 2002, the ICDP, the NSF, and the USGS provided funding for a pilot hole project at the SAFOD site. Twenty scientifi c papers summarizing the results of the pilot hole project as well as pre-SAFOD site characterization studies were published in Geophysical Research Letters (Vol.31, Nos. 12 and 15, 2004). 2006 1816-8957 doi:10.2204/iodp.sd.2.07.2006 Scientific Drilling 2006 32-33 2 https://www.ingentaconnect.com/content/doaj/18168957/2006/00002006/00000002/art00007 Mark D. Zoback article Roecker2006189 The Parkfield Area Seismic Observatory (PASO) was a dense, telemetered seismic array that operated for nearly 2 years in a 15 km aperture centered on the San Andreas Fault Observatory at Depth (SAFOD) drill site. The main objective of this deployment was to refine the locations of earthquakes that will serve as potential targets for SAFOD drilling and in the process develop a high (for passive seismological techniques) resolution image of the fault zone structure. A challenging aspect of the analysis of this data set was the known existence of large (20-25%) contrasts in seismic wavespeed across the San Andreas Fault. The resultant distortion of raypaths could challenge the applicability of approximate ray tracing techniques. In order to test the sensitivity of our hypocenter locations and tomographic image to the particular ray tracing and inversion technique employed, we compare an initial determination of locations and structure developed using a coarse grid and an approximate ray tracer [Thurber, C., Roecker, S., Roberts, K., Gold, M., Powell, M.L., and Rittger, K., 2003. Earthquake locations and three-dimensional fault zone structure along the creeping section of the San Andreas fault near Parkfield, CA: Preparing for SAFOD, Geophys. Res. Lett., 30 3, 10.1029/2002GL016004.] with one derived from a relatively fine grid and an application of a finite difference algorithm [Hole, J.A., and Zelt, B.C., 1995. 3-D finite-difference reflection traveltimes, Geophys. J. Int., 121, 2, 427-434.]. In both cases, we inverted arrival-time data from about 686 local earthquakes and 23 shots simultaneously for earthquake locations and three-dimensional Vp and Vp/Vs structure. Included are data from an active source seismic experiment around the SAFOD site as well as from a vertical array of geophones installed in the 2-km-deep SAFOD pilot hole, drilled in summer 2002. Our results show that the main features of the original analysis are robust: hypocenters are located beneath the trace of the fault in the vicinity of the drill site and the positions of major contrasts in wavespeed are largely the same. At the same time, we determine that shear wave speeds in the upper 2 km of the fault zone are significantly lower than previously estimated, and our estimate of the depth of the main part of the seismogenic zone decreases in places by ∼ 100 m. Tests using "virtual earthquakes" (borehole receiver gathers of picks for surface shots) indicate that our event locations near the borehole currently are accurate to about a few tens of meters horizontally and vertically. © 2006 Elsevier B.V. All rights reserved. 2006 English 00401951 10.1016/j.tecto.2006.02.026 Tectonophysics 426 189-205 Rensselaer Polytechnic Institute, Troy, NY, United States; University of Wisconsin-Madison, Madison, WI, United States 1-2 data inversion; fault zone; ray tracing; seismic tomography; seismic zone; travel time, California; North America; Parkfield; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-33749523010&doi=10.1016%2fj.tecto.2006.02.026&partnerID=40&md5=96e8bd6570a6b0fb6ce570bbf699ad24 cited By 65 S. Roecker C. Thurber K. Roberts L. Powell article Bellefleur2006599 Gas-hydrate accumulations located onshore in Arctic permafrost regions are seen as a potential source of natural gas. Surprisingly, most of the gas hydrate found in the Mackenzie Delta and Beaufort Sea areas was indirectly discovered or inferred from conventional hydrocarbon exploration programs. One of these occurrences, the Mallik gas-hydrate field (Figure 1), has received particular attention over the last 10 years. Two internationally partnered research well programs have intersected three intervals of gas hydrates and have allowed successful extraction of subpermafrost core samples with significant gas hydrates. The gas-hydrate intervals are up to 40 m thick and have high gas-hydrate saturation, sometimes exceeding 80% of pore volume of unconsolidated clastic sediments with average porosities from 25-40%. At Mallik, the gas-hydrate intervals are located at depths of 900-1100 m and are localized on the crest of an anticline. © 2006 Society of Exploration Geophysicists. 2006 English 1070485X 10.1190/1.2202663 Leading Edge 25 Society of Exploration Geophysicists 599-604 Geological Survey of Canada, Ottawa, Canada; Geological Survey of Canada, Pacific, Sidney, B.C., Canada; Geological Survey of Canada, Calgary, Canada 5 Gases; Hydration; Petroleum prospecting, Clastic sediments; Conventional hydrocarbons; Gas hydrate saturations; Hydrate accumulations; Permafrost region; Potential sources; Significant gas; Three interval, Gas hydrates, clastic sediment; gas hydrate; hydrocarbon exploration; natural gas; permafrost; porosity; supermarket, Arctic; Arctic Ocean; Beaufort Sea; Canada; Mackenzie Delta; Northwest Territories https://www.scopus.com/inward/record.uri?eid=2-s2.0-84889901633&doi=10.1190%2f1.2202663&partnerID=40&md5=5ce5a582159ac08e1393ce371b35b818 cited By 39 G. Bellefleur M. Riedel T. Brent article Su2006575 The only main hole of the Chinese Continental Scientific Drilling (CCSD) Project, the deepest scientific drilling project of all the ICDP projects, reached its depth of over 5000 m, from which more than 4400 m cores were collected. Hence the scanned core image database of CCSD project is also the largest of all the databases of ICDP projects. After various samplings, some cores have been completely damaged or disappeared. To make full use of the scanned core images, an MS ACCESS database was developed, on the basis of the original DIS system. More than 8000 images (about 100 gigabyte) have been efficiently and systematically managed and shared on the Internet with some user-friendly query program and interfaces using the ASP and VB techniques. This new information technology, proved by one year trial test, can not only store permanently and efficiently the original image data, but also help geologists to study efficiently the cores for their scientific purpose. 2006 Chinese 10002383 Diqiu Kexue - Zhongguo Dizhi Daxue Xuebao/Earth Science - Journal of China University of Geosciences 31 575-577 Key Laboratory for Continental Dynamics of MLR, Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China; State Key Laboratory of Loess and Quaternary Geology, Chinese Academy of Sciences, Xi'an 710075, China; Beijing Huaxing Corporation for Exploration and New Techniques, Beijing 100035, China 4 Database systems; Image processing; Information technology; Interfaces (computer); Internet; Sampling; Scanning, Chinese Continental Scientific Drilling; Data share; Scanned core image; User friendly interface, Drilling https://www.scopus.com/inward/record.uri?eid=2-s2.0-33748944498&partnerID=40&md5=0c83747b0a5794e76aad118c8481e83b cited By 0 D.-C. Su W. Wang A.-P. Sun L.-M. Guo Y.-H. Zhou article Wilson200639 2006 English 00092347 10.1021/cen-v084n004.p039 Chemical and Engineering News 84 American Chemical Society 39-41 C and EN West Coast News Bureau, New Zealand 4 Flow of fluids; Pressure effects; Real time systems; Rocks; Tectonics, Chemical clue; Frictional change; San Andreas Fault; San Andreas Fault Observatory at Depth (SAFOD),, Earthquakes https://www.scopus.com/inward/record.uri?eid=2-s2.0-33746610246&doi=10.1021%2fcen-v084n004.p039&partnerID=40&md5=73a4f3de52cbc0f221733193f3904fa1 cited By 0 E.K. Wilson article Heuer2006 Detailed images of the lithosphere beneath the western Bohemian Massif were obtained by analysis of more than 8500 P receiver functions. At the intersection of Regensburg-Leipzig-Rostock zone and Eger Rift, crustal thickness decreases to 26 km from approx. 31 km in the surroundings. The receiver functions display a positive phase at about 6 s delay time and a strong negative phase at 7 to 8 s, which coincides with an area of Moho updoming, CO2 mantle-derived degassing and earthquake swarm activity. These phases can be modeled by a velocity increase at 50 km and a velocity decrease at 65 km depth. The velocity decrease, observed over an area of 5300 km2, gives evidence for local asthenospheric updoming and/or a confined body of partial melt, which might be the cause for high CO2 mantle fluid flow and earthquake swarm activity in this recently nonvolcanic, intracontinental rift area. Copyright 2006 by the American Geophysical Union. Article 2006 English 00948276 10.1029/2005GL025158 Geophysical Research Letters 33 5 Bohemian Massif; Central Europe; Eurasia; Europe; Carbon dioxide; Degassing; Earthquakes; Flow of fluids; Tectonics; asthenosphere; crustal thickness; earthquake swarm; fluid flow; imaging method; mantle process; Asthenospheric updoming; Carbon dioxide mantle-derived degassing; Earthquake swarm activity; Seismology https://www.scopus.com/inward/record.uri?eid=2-s2.0-33646363323&doi=10.1029%2f2005GL025158&partnerID=40&md5=51c682b149950f1a934424e6a07e7e81 Cited by: 57; All Open Access, Bronze Open Access B. Heuer W.H. Geissler R. Kind H. Kämpf article Grygar2006240 Measurement of magnetic susceptibility (MS) and diffuse reflectance spectra (DRS) were used to construct environmental proxies in a 6.5 m section of the sediment core VER98-1-13 from the Academician Ridge, Lake Baikal. The interpretation of MS and DRS was supported by X-ray diffraction and microparticle voltammetry to identify the main Fe-bearing minerals. The record of the relative paleointensity of the Earth's magnetic field was used to construct an age model showing the core interval covers the last 160 ky. The time resolution of the record was ∼1 ky. The main environmental changes were recognized by a combination of DRS and MS records and compared to marine isotopic stages in addition to the diatom record from 120 to 60 ky BP so as to demonstrate the importance of these inorganic proxies as paleoenvironmental records. A dramatic climatic deterioration between 66 and 60 ky BP was probably preceded by a dry intermediate stage between 77 and 66 ky BP. The DRS-based proxies of Fe(II) / Fe(III) ratios in the mineral assemblage, MS and/or diatom records clearly reveal 1-2 ky long environmental extremes at 110, 103, 90, 85, 77, 61, 54, 36, 27, 23, and 19 ky BP. The majority of these extremes were contemporaneous with discharges of North Atlantic and Arctic Ocean icebergs (Heinrich events) documenting a teleconnection between the North Atlantic Ocean and East Central Siberia. These sharp changes coincided with a major transition to the colder climatic stages of the last 100 ky. © 2006. Article 2006 English 00310182 10.1016/j.palaeo.2005.12.007 Palaeogeography, Palaeoclimatology, Palaeoecology 237 240 – 254 2-4 Arctic Ocean; Atlantic Ocean; Atlantic Ocean (North); Eurasia; Lake Baikal; Russian Federation; Siberia; Bacillariophyta; climate change; environmental change; fossil record; magnetic susceptibility; paleoenvironment; reflectance; sediment analysis; X-ray diffraction https://www.scopus.com/inward/record.uri?eid=2-s2.0-33745926535&doi=10.1016%2fj.palaeo.2005.12.007&partnerID=40&md5=3384c52baadc2801dd3b5bef26903003 Cited by: 22 T. Grygar J. Kadlec P. Pruner G. Swann P. Bezdička D. Hradil K. Lang K. Novotna H. Oberhänsli article Haberer2006519 The aromatic hydrocarbon biomarker distributions of thirty Oligocene sediment samples with different lithology (lignite, clay and sand) from the JAPEX/JNOC/GSC et al. Mallik 5L-38 Gas Hydrate Production Research Well, Canada, were analyzed using gas chromatography-mass spectrometry (GC-MS). The compositions vary with lithology, indicating a change in palaeoenvironmental conditions at the time of deposition. Aromatic diterpenoids of the abietane type are more abundant in the lignite samples than in the clay samples and represent a gymnosperm (e.g., conifer) dominated palaeovegetation. In contrast, in the clay samples aromatic triterpenoids are generally preserved as major constituents, indicating angiosperm dominated vegetation. The sand samples contain only minor amounts of aromatic terpenoids, but show a preference for diterpenoid gymnosperm markers. To recognise gymnosperm versus angiosperm dominated palaeoenvironments a new ratio, termed the angiosperm-gymnosperm aromatic ratio (AGAR), has been developed. Thus, the terpenoid distribution in the deltaic sediments provides information on the compositional changes in the plant community at the Mallik site (lignites) and the hinterland (clays) over time. Concomitantly, the changing dominance in the plant communities allows an insight into varying climatic conditions during the late Oligocene in the area. Additionally, the aromatic biomarker composition has been used to assess the level of thermal maturity of the organic matter in the Mallik samples and indicates a prevailing immature character. © 2006 Elsevier Ltd. All rights reserved. 2006 English 01466380 10.1016/j.orggeochem.2006.01.004 Organic Geochemistry 37 519-538 GeoForschungsZentrum (GFZ) Potsdam, Telegrafenberg, D-14473 Potsdam, Germany 5 Angiosperm-gymnosperm aromatic ratio (AGAR); Aromatic diterpenoids; Climatic conditions; Gymnosperm markers, Aromatic hydrocarbons; Composition; Environmental impact; Gas chromatography; Hydration; Mass spectrometry; Sediments, Biomarkers, aromatic hydrocarbon; biomarker; geochemistry; Oligocene; paleoenvironment; sediment; vegetation, Canada; North America, Coniferophyta; Gymnospermae; Magnoliophyta https://www.scopus.com/inward/record.uri?eid=2-s2.0-33646467368&doi=10.1016%2fj.orggeochem.2006.01.004&partnerID=40&md5=d583b2b30952fca4aad2fc7f2128f543 cited By 61 R.M. Haberer K. Mangelsdorf H. Wilkes B. Horsfield article Shanahan2006287 A detailed investigation of geomorphological evidence of paleoshorelines and exposed stratigraphic sections of lake deposits, combined with a chronology based on radiocarbon dated charcoal and in-situ 14C dating of wave polished bedrock, provide important new constraints on lake level changes of Lake Bosumtwi, Ghana. Thick sequences of laminated silts, alternating with transgressive sands and deltaic gravels, attest to a long history of climatically controlled lake level variations. The post-glacial rise in lake level began sometime after 16.3 ka, reached stable levels first at 14.5 ± 0.6 ka and then rose again after ca. 14.3 ka. A significant lake level regression spanned the interval from 12.6 ± 0.3 to 11.6 ± 0.5 ka, synchronous with the Younger Dryas. Deep lake conditions were reestablished after ca. 11 ka, at which time the lake overtopped the crater. Overflow continued until 8.8 ± 0.5 ka, when another significant but short-lived regression occurred. Deep, but probably not overflowing conditions were again reestablished by > 7.2 ± 0.3 ka and continued until around 3.2 ± 0.1 ka, when lake level dropped precipitously. Multicentury late Holocene highstands occurred at 2.2 ± 0.1 and 1.7 ± 0.2 ka, although these were significantly lower than those registered in the late glacial and early Holocene. The timing of late glacial events is similar to those recorded elsewhere in Africa and the higher latitudes, and likely reflects the dominant control of high latitude northern hemisphere conditions on the African tropics during the times of large northern hemisphere ice sheets. Mid- to late-Holocene variations appear to be less coupled with changes across Africa and elsewhere, suggesting that regional forcing may be more important during warmer periods. © 2006. Article 2006 English 00310182 10.1016/j.palaeo.2006.06.007 Palaeogeography, Palaeoclimatology, Palaeoecology 242 287 – 302 3-4 Africa; Ashanti; Ghana; Lake Bosumtwi; Sub-Saharan Africa; West Africa; climate variation; crater lake; highstand; Holocene; ice sheet; lacustrine deposit; lake level; Last Glacial; monsoon; paleoclimate; Pleistocene; radiocarbon dating; Younger Dryas https://www.scopus.com/inward/record.uri?eid=2-s2.0-33750980556&doi=10.1016%2fj.palaeo.2006.06.007&partnerID=40&md5=f4fffa937d0dd36e93a9853708b82033 Cited by: 127 Timothy M. Shanahan Jonathan T. Overpeck C. Winston Wheeler J. Warren Beck Jeffrey S. Pigati Michael R. Talbot Christopher A. Scholz John Peck John W. King article Cohen2006161 Conference paper 2006 English 00963941 10.1029/2006eo160008 Eos 87 Blackwell Publishing Ltd 161 16 human evolution; Neogene; paleoclimate https://www.scopus.com/inward/record.uri?eid=2-s2.0-34447639111&doi=10.1029%2f2006eo160008&partnerID=40&md5=e7dcf16bf4a18ce7c76375efec71711e Cited by: 2; All Open Access, Bronze Open Access Andrew S. Cohen Gail M. Ashley Richard Potts Anna K. Behrensmeyer Craig Feibel Jay Quade article Sakhno20061351 2006 English 1028334X 10.1134/S1028334X06090042 Doklady Earth Sciences 411 Maik Nauka-Interperiodica Publishing 1351-1356 Far East Geological Institute, Far East Division, Russian Academy of Sciences, pr. Stoletiya Vladivostoka 159, Vladivostok 660022, Russian Federation; Institute of Volcanology and Seismology, Far East Division, Russian Academy of Sciences, bul'v. Piipa 9, Petropavlosk-Kamchatskii 683006, Russian Federation; Northeastern Complex Research Institute, Far East Division, Russian Academy of Sciences, ul. Portovaya, Magadan, Russian Federation; Geological Institute, Russian Academy of Sciences, Pyzhevskii per. 7, Moscow 119017, Russian Federation; Institute of the Geology of Diamond and Noble Metals, Siberian Division, Russian Academy of Sciences, pr. Lenina 39, Yakutsk 677980, Russian Federation; University of Leipzig, Leipzig, Germany 2 Pleistocene-Holocene boundary; rare earth element; trace element; volcanic ash; volcanic eruption https://www.scopus.com/inward/record.uri?eid=2-s2.0-36549007607&doi=10.1134%2fS1028334X06090042&partnerID=40&md5=a25e4840e0fb865b8c8c7001eebc8b82 cited By 4 V.G. Sakhno L.I. Bazanova O.Yu. Glushkova I.V. Melekestsev V.V. Ponomareva A.A. Surnin J. Olaf article Schleicher2006 The clay mineralogy and texture of rock fragments from the SAFOD borehole at 3067 m and 3436 m measured depth (MD) was investigated by electron microscopy (SEM, TEM) and X-ray-diffraction (XRD). The washed and ultrasonically cleaned samples show slickenfiber striations and thin films of Ca-K bearing smectite that are formed on polished fault surfaces, along freshly opened fractures and within adjacent mineralized veins. The cation composition and hydration behavior of these films differ from the Namontmorillonite of the fresh bentonite drilling mud, although there is more similarity with circulated mud recovered from 3479 m MD. We propose that these thin film smectite precipitates formed by natural nucleation and crystal growth during fault creep, probably associated with the shallow circulation of low temperature aqueous fluids along this shallow portion of the San Andreas Fault. Copyright 2006 by the American Geophysical Union. 2006 English 00948276 10.1029/2006GL026505 Geophysical Research Letters 33 American Geophysical Union Department of Geological Sciences, University of Michigan, Ann Arbor, MI, United States; Universität Würzburg, Geologisches Institut, Würzburg, Germany; Earthquake Hazards Team, U.S. Geological Survey, Menlo Park, CA, United States; Centre de Géochimie de la Surface, Université Louis Pasteur, CNRS, Strasbourg, France; Department of Geological Sciences, University of Michigan, 4534b C. C. Little Building, 1100 N. University Ave., Ann Arbor, MI 48109-1005, United States; Earthquake Hazards Team, U.S. Geological Survey, MS 977, 345 Middlefield Road, Menlo Park, CA 94025, United States; Centre de Géochimie de la Surface, Université Louis Pasteur, CNRS, 1 rue Blessig, F-67084 Strasbourg, France 16 Clay; Crystal growth; Rocks; Scanning electron microscopy; Textures; Thin films; Transmission electron microscopy; X ray diffraction analysis, Aqueous fluids; Drilling mud; Fault creep; Slickenfiber striations, Boreholes, bentonite; borehole; calcium; cation; clay; crystal structure; hydration; mudstone; potassium; rock property; sampling; San Andreas Fault; scanning electron microscopy; smectite; texture; transmission electron microscopy; X-ray diffraction https://www.scopus.com/inward/record.uri?eid=2-s2.0-33845669469&doi=10.1029%2f2006GL026505&partnerID=40&md5=eaab60d782d571cc151be4548cea5a09 cited By 67 A.M. Schleicher J.G. Solum L.N. Warr article Prokopenko20063431 A new composite BDP-96 biogenic silica record over the entire Pleistocene was generated by splicing BDP-96-1 and BDP-96-2 drill cores from Lake Baikal, crosschecked against a similar record from a nearby BDP-98 drill core. A new astronomically tuned age model is proposed based on correlating peak biogenic silica responses with the timing of September perihelia. This target is derived from analysis of regional climate proxy responses during the Holocene, the last interglacial and around paleomagnetic reversals. By resolving virtually every precessional cycle during the Pleistocene, the new age model represents a major improvement compared with previously reported Lake Baikal timescales. The astronomically tuned ages of the Pleistocene paleomagnetic reversals are consistent with published dates. The minimal tuning approach we used (precession only) has also aligned high signal power in a narrow obliquity band, confirming the strong presence of orbital forcing. There are also strong ca 100-ka scale cycles, but these are not aligned with the orbital eccentricity. Despite the location of Lake Baikal in a continental interior that is highly sensitive to insolation forcing, the tuned biogenic silica record reveals a consistent phase difference of -32° (ca 4 ka) relative to insolation in the obliquity band. An inherent lag embedded in a continental proxy record, not driven by global ice volume, is an intriguing finding. Another new observation is that long-term changes in sedimentation rates in Lake Baikal appear to be related to the amplitude of orbital forcing; both amplitudes and sedimentation rates undergo significant changes during MIS 24-MIS 19 interval corresponding to the Middle Pleistocene Transition. With potential for linking continental and marine climato-stratigraphies, the new Baikal record serves a new benchmark correlation target in continental Eurasia, as an alternative to June 65°N insolation and ODP-correlated timescales. © 2006 Elsevier Ltd. All rights reserved. Article 2006 English 02773791 10.1016/j.quascirev.2006.10.002 Quaternary Science Reviews 25 3431 – 3457 23-24 Eurasia; Lake Baikal; Russian Federation; Siberia; Astronomy; Cell culture; Correlation methods; Glaciers; Lakes; Mathematical models; Sedimentation; age determination; biogenic mineral; climate change; Holocene; insolation; magnetic reversal; orbital forcing; paleoclimate; Pleistocene; precession; proxy climate record; sedimentation rate; silica; Astronomically tuned climatic records; Biogenic silica; Pleistocene paleomagnetic reversals; Regional climate; Climate change https://www.scopus.com/inward/record.uri?eid=2-s2.0-33846798134&doi=10.1016%2fj.quascirev.2006.10.002&partnerID=40&md5=e386f57078e209c6264342cdfe95df47 Cited by: 152 Alexander A. Prokopenko Linda A. Hinnov Douglas F. Williams Mikhail I. Kuzmin article cremer2006pliocaenicus 2006 European Journal of Phycology 41 Taylor & Francis 169-178 2 Holger Cremer Bart Vijver conference Krüger20062483 This work is inspired by the observation, that gas hydrate bearing sediments have a high velocity in combination with high attenuation. We study numerically the influence of different gas hydrate locations within the pore space on transmitted p-waves. From the wave propagation simulations on the micro-scale it can be seen, that different positions of the gas hydrate in the pore space results in almost the same effective velocities and attenuation, as long as the gas hydrate had contact to the sediment grains. This changes in the case of a suspension, here the attenuation increases and the effective velocity decreases. The resulting p-wave versus gas hydrate saturation plot is in a qualitatively good agreement with experimental results obtained for the Mallik 2L-38 well. Copyright 2006, European Association of Geoscientists and Engineers. 2006 English Society of Petroleum Engineers, 68th European Association of Geoscientists and Engineers Conference and Exhibition, incorporating SPE EUROPEC 2006, EAGE 2006: Opportunities in Mature Areas 5 Society of Petroleum Engineers 2483-2487 Freie Universitaet Berlin, Germany Computer simulation; Gas hydrates; Numerical methods; Sediments; Velocity measurement; Wave propagation; Wave transmission, Attenuation; Gas hydrate locations; Gas hydrate saturation; Sediment grains, Microstructure https://www.scopus.com/inward/record.uri?eid=2-s2.0-33947224472&partnerID=40&md5=7eafe412174b684a494ddcd756ba93cd cited By 0 O.S. Krüger E.H. Saenger S.R. Zanoth S.A. Shapiro article Santos20062986 We analyze the reflectivity properties of the interfaces defined by a contact between a shaly sandstone and the top and bottom of a gas hydrate stability zone (GHSZ), a problem of particular interest in seismic exploration in ocean sediments and continental margins. Our com putations are based on a three phase Biot-type model predicting the existence of three compressional waves and two shear waves. We use some information from the Mallik 5L-38 Gas Hydrate Research Well. The mechanical properties of the gas hydrate bearing rocks are described with appropriate petrophysical models. We present numerical results showing the influence of the gas-hydrate saturation on the amplitude vs. angle curves and the importance of wave energy conversion from fast to slow waves. © 2005 Society of Exploration Geophysicists. 2006 English 9781604236972 10523812 10.1190/1.2370148 SEG Technical Program Expanded Abstracts 25 Society of Exploration Geophysicists 2986-2990 Facultad de Ciencias Astronómicas y Geofísicas, Universidad Nacional de La Plata, CONICET, Paseo del Bosque S/N, 1900-La Plata, Argentina; CONICET, Argentina; Department of Mathematics, Purdue University, W. Lafayette, IN 47907, United States 1 Bearings (machine parts); Energy conversion; Gas hydrates; Gases; Hydration; Petroleum prospecting; Reflection; Seismic prospecting; Shear flow; Shear waves; Wave energy conversion, Compressional waves; Continental margin; Gas hydrate saturations; Gas hydrate stability zones; Numerical results; Ocean sediments; Petrophysical models; Seismic exploration, Phase interfaces https://www.scopus.com/inward/record.uri?eid=2-s2.0-33845425790&doi=10.1190%2f1.2370148&partnerID=40&md5=8806108548e2bffacf26df246f544a86 cited By 0 J.E. Santos J.G. Rubino C.L. Ravazzoli conference Rubino2006 Using an interval of real log data from the Mallik 5L38 Gas Hydrate Research Well, we estimate empirical relations for some mechanical properties of the gas hydrate frame. This is an important problem for geophysical exploration in gas hydrate bearing sediments, a subject which has not received as much attention as it deserves from the researchers in this field. The theoretical velocities used to model the sonic logs are computed using a Biottype formulation combined with known petrophysical models for shaley sandstones. The empirical results are also applied to obtain estimates of gas hydrate saturations at a different depth interval from sonic and density log data, showing the applicability of this approach. 2006 English Saint Petersburg 2006 International Conference and Exhibition European Association of Geoscientists and Engineers, EAGE CONICET, Universidad Nacional de la Plata, Argentina Exhibitions; Gases; Geophysical prospecting; Hydration; Mechanical properties; Radioactivity logging; Research, Density log; Empirical relations; Gas hydrate bearing sediments; Gas hydrate saturations; Geophysical exploration; P- and S-wave velocities; Petrophysical models; Sonic logs, Gas hydrates https://www.scopus.com/inward/record.uri?eid=2-s2.0-84898970202&partnerID=40&md5=05631e357a117c5867b1e6d234104136 cited By 0 J.G. Rubino C.L. Ravazzoli J.E. Santos article Newsom20061929 The concentrations of the fluid mobile trace elements lithium, beryllium, boron, and barium were measured in samples of the altered matrix of several impactite breccias of the Yaxcopoil-1 drill core using secondary ion mass spectrometry (SIMS) to determine the extent of transport due to aqueous or hydrothermal processes. Three of the elements, Li, Be, and B, have higher concentrations in the upper suevite impact breccias than in the lower impact melt deposits by factors of 3.5, 2.2, and 1.5, respectively. Lithium and B are the most enriched elements up section, and appear to have had the greatest mobility. The similar fractionation of Li and B is consistent with fluid transport and alteration under low-temperature conditions of less than 150 °C based on published experimental studies. In contrast to Li, Be, and B, the concentration of Ba in the altered matrix materials decreases upward in the section, and the concentration of Ba in the matrix is an order of magnitude less than the bulk concentrations, likely due to the presence of barite. The origin of the elemental variations with depth may be related to different protolith compositions in the upper versus the lower impactite units. A different protolith in the altered matrix is suggested by the Mg-rich composition of the tower units versus the Al-rich composition of the upper units, which largely correlates with the mobile element variations. The possibility that vertical transport of mobile elements is due to a postimpact hydrothermal system is supported by published data showing that the sediments immediately overlying the impactites are enriched in mobile elements derived from a hydrothermal system. However, the mobile elements in the sediments do not have to originate from the underlying impactites. In conclusion, our data suggests that the impactites at this location did not experience extensive high-temperature hydrothermal processing, and that only limited transport of some elements, including Li, Be, and B, occurred. © The Meteoritical Society, 2006. 2006 10.1111/j.1945-5100.2006.tb00461.x Meteoritics and Planetary Science 41 1929-1945 Institute of Meteoritics, Department of Earth and Planetary Sciences, Albuquerque, NM 87131, United States; 5481 Oceanview Terrace, Nanaimo, BC V9V 1G7, Canada 12 https://www.scopus.com/inward/record.uri?eid=2-s2.0-33846096690&doi=10.1111%2fj.1945-5100.2006.tb00461.x&partnerID=40&md5=13dc09879add2395bfe3ecc1d11de3b5 cited By 6 H.E. Newsom M.J. Nelson C.K. Shearer B.O. Dressler article Bernard20067 This paper presents the main recent results obtained by the seismological and geophysical monitoring arrays in operation in the rift of Corinth, Greece. The Corinth Rift Laboratory (CRL) is set up near the western end of the rift, where instrumental seismicity and strain rate is highest. The seismicity is clustered between 5 and 10 km, defining an active layer, gently dipping north, on which the main normal faults, mostly dipping north, are rooting. It may be interpreted as a detachment zone, possibly related to the Phyllade thrust nappe. Young, active normal faults connecting the Aigion to the Psathopyrgos faults seem to control the spatial distribution of the microseismicity. This seismic activity is interpreted as a seismic creep from GPS measurements, which shows evidence for fast continuous slip on the deepest part on the detachment zone. Offshore, either the shallowest part of the faults is creeping, or the strain is relaxed in the shallow sediments, as inferred from the large NS strain gradient reported by GPS. The predicted subsidence of the central part of the rift is well fitted by the new continuous GPS measurements. The location of shallow earthquakes (between 5 and 3.5 km in depth) recorded on the on-shore Helike and Aigion faults are compatible with 50° and 60° mean dip angles, respectively. The offshore faults also show indirect evidence for high dip angles. This strongly differs from the low dip values reported for active faults more to the east of the rift, suggesting a significant structural or rheological change, possibly related to the hypothetical presence of the Phyllade nappe. Large seismic swarms, lasting weeks to months, seem to activate recent synrift as well as pre-rift faults. Most of the faults of the investigated area are in their latest part of cycle, so that the probability of at least one moderate to large earthquake (M = 6 to 6.7) is very high within a few decades. Furthermore, the region west to Aigion is likely to be in an accelerated state of extension, possibly 2 to 3 times its mean interseismic value. High resolution strain measurement, with a borehole dilatometer and long base hydrostatic tiltmeters, started end of 2002. A transient strain has been recorded by the dilatometer, lasting one hour, coincident with a local magnitude 3.7 earthquake. It is most probably associated with a slow slip event of magnitude around 5 ± 0.5. The pore pressure data from the 1 km deep AIG10 borehole, crossing the Aigion fault at depth, shows a 1 MPa overpressure and a large sensitivity to crustal strain changes. © 2006 Elsevier B.V. All rights reserved. Article 2006 English 00401951 10.1016/j.tecto.2006.02.012 Tectonophysics 426 7 – 30 1-2 Gulf of Corinth; Ionian Sea; Mediterranean Sea; active fault; deformation; earthquake magnitude; geophysical survey; normal fault; seismic hazard; seismicity https://www.scopus.com/inward/record.uri?eid=2-s2.0-33749527880&doi=10.1016%2fj.tecto.2006.02.012&partnerID=40&md5=d5c90b0514c7e77340c03b5cb704a2b0 Cited by: 132 P. Bernard H. Lyon-Caen P. Briole A. Deschamps F. Boudin K. Makropoulos P. Papadimitriou F. Lemeille G. Patau H. Billiris D. Paradissis K. Papazissi H. Castarède O. Charade A. Nercessian A. Avallone F. Pacchiani J. Zahradnik S. Sacks A. Linde article Solum2006 Washed cuttings provide a continuous record of the rocks encountered during drilling of the main hole of the San Andreas Fault Observatory at Depth (SAFOD). Both protolith and fault rocks exhibit a wide variety of mineral assemblages that reflect variations in some combination of lithology, P-T conditions, deformation mechanisms, and fluid composition and abundance. Regions of distinct neomineralization bounded by faults may record alteration associated with fluid reservoirs confined by faults. In addition, both smectites occurring as mixed-layer phases and serpentine minerals are found in association with active strands of the San Andreas Fault that were intersected during drilling, although their rheological influence is not yet fully known. Faults containing these mineralogical phases are prime candidates for continuous coring during Phase 3 of SAFOD drilling in the summer of 2007. Copyright 2006 by the American Geophysical Union. 2006 English 00948276 10.1029/2006GL027285 Geophysical Research Letters 33 Earthquake Hazards Team, U.S. Geological Survey, Menlo Park, CA, United States; Department of Geological Sciences, University of Michigan, Ann Arbor, MI, United States; Department of Geology, Utah State University, Logan, UT, United States; Department of Geology, Utah State University, 4505 Old Main Hill, Logan, UT 84322-4505, United States; Earthquake Hazards Team, U.S. Geological Survey, MS 977, 345 Middlefield Road, Menlo Park, CA 94025, United States; Department of Geological Sciences, University of Michigan, Little Bldg., 1100 N. University Ave., 2534 C.C, Ann Arbor, MI 48109, United States 21 Deformation; Reservoirs (water); Rheology; Rock drilling; Rocks; Serpentine, Fluid reservoirs; Mineralogical phases; Smectites; Washed cuttings, Geophysics, drilling; fault; lithology; mineralogy; protolith; rock; summer, California; North America; San Andreas; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-34248522543&doi=10.1029%2f2006GL027285&partnerID=40&md5=f63de7ab4297b514d845f0aca9f87f76 cited By 97 J.G. Solum S.H. Hickman D.A. Lockner D.E. Moore A.M. Schleicher J.P. Evans article Cordon2006 We perturb the elastic properties and attenuation in the Arctic Mallik methane-hydrate reservoir to produce a set of plausible seismic signatures away from the existing well. These perturbations are driven by the changes we impose on porosity, clay content, hydrate saturation, and geometry. The key is a data-guided, theoretical, rock-physics model that we adopt to link velocity and attenuation to porosity, mineralogy, and amount of hydrate. We find that the seismic amplitude is very sensitive to the hydrate saturation in the host sand and its porosity as well as the porosity of the overburden shale. However, changes to the amount of clay in the sand only weakly alter the amplitude. Attenuation, which may be substantial, must be taken into account during hydrate reservoir characterization because it lowers the amplitude to an extent that may affect the hydrate-volume prediction. The spatial structure of the reservoir affects the seismic reflection: A thinly-layered reservoir produces a noticeably different amplitude than a massive reservoir with the same hydrate volume. © 2006 Society of Exploration Geophysicists. 2006 English 00168033 10.1190/1.2356909 Geophysics 71 Society of Exploration Geophysicists F165-F171 Stanford University, Stanford Rock Physics Laboratory, Geophysics Department, 397 Panama Mall, Stanford, CA 94305, United States 6 Gas hydrates; Mineralogy; Organic compounds; Perturbation techniques; Petroleum reservoirs; Porosity; Reflection, Seismic amplitude; Seismic reflections, Seismology, amplitude; clay; elastic property; porosity; sand; seismic attenuation; seismic reflection; seismic velocity; seismology https://www.scopus.com/inward/record.uri?eid=2-s2.0-33751047705&doi=10.1190%2f1.2356909&partnerID=40&md5=6187bd113d49e95517f197c284b9dda9 cited By 12 I. Cordon J. Dvorkin G. Mavko article Bakulin2006379 We analyze cross-well seismic data from the Mallik experiment and demonstrate time-lapse changes in tube and guided waves. Although such changes are challenging to interpret, they are generally of a larger magnitude compared to any time-lapse signatures of the first P-wave arrivals reported elsewhere. This suggests better sensitivity of tube and guided waves to small production-related changes and their feasibility for reservoir monitoring. © 2005 Society of Exploration Geophysicists. 2006 English 9781604236972 10523812 10.1190/1.2370280 SEG Technical Program Expanded Abstracts 25 Society of Exploration Geophysicists 379-383 Shell International Exploration and Production Inc, United States; Lawrence Berkeley National Laboratory, United States; Nagoya University, Japan; St. Petersburg State University, St. Petersburg, Russian Federation 1 Geophysical prospecting; Seismic waves; Seismology, Cross-well; P-wave arrival; Reservoir monitoring; Seismic datas, Guided electromagnetic wave propagation https://www.scopus.com/inward/record.uri?eid=2-s2.0-33845415179&doi=10.1190%2f1.2370280&partnerID=40&md5=c30cb7bef36066a051200e0fccf15b0d cited By 4 A. Bakulin V. Korneev T. Watanabe S. Ziatdinov article ElwoodMadden2006247 This study examines the effects of shock metamorphism on fluid inclusions in crystalline basement target rocks from the Ries crater, Germany. The occurrence of two-phase fluid inclusions decreases from shock stage 0 to shock stage 1, while single-phase inclusions increase, likely as a result of re-equilibration. In shock stages 2 and 3, both two-phase and single-phase inclusions decrease with increasing shock stage, indicating that fluid inclusion vesicles are destroyed due to plastic deformation and phase changes in the host minerals. However, quartz clasts entrained in shock stage 4 melts contain both single-phase and two-phase inclusions, demonstrating the rapid quenching of the melt and the heterogeneous nature of impact deformation. Inclusions in naturally shocked polycrystalline samples survive at higher shock pressures than those in single crystal shock experiments. However, fluid inclusions in both experimental and natural samples follow a similar trend in re-equilibration at low to moderate shock pressures leading to destruction of inclusion vesicles in higher shock stages. This suggests that shock processing may lead to the destruction of fluid inclusions in many planetary materials and likely contributed to shock devolatilization of early planetesimals. © The Meteoritical Society, 2006. 2006 10.1111/j.1945-5100.2006.tb00208.x Meteoritics and Planetary Science 41 247-262 Department of Geosciences, Virginia Polytechnic Institute, Blacksburg, VA 24060, United States; Lunar and Planetary Laboratory, The University of Arizona, Tucson, AZ 85721, United States; Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6036, United States 2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-33645468128&doi=10.1111%2fj.1945-5100.2006.tb00208.x&partnerID=40&md5=6a2dff61c05b11df647ca70b3674a005 cited By 3 M.E. Elwood Madden D.A. Kring R.J. Bodnar article Hodell200625 2006 English 18168957 10.2204/iodp.sd.3.02.2006 Scientific Drilling 1 25-29 Department of Geological Sciences, Land Use and Environmental Change Institute (LUECI), University of Florida, 441 Williamson Hall, Gainesville, FL 32611, United States; Geological Institute, Swiss Federal Institute of Technology, ETH, Zurich Universtätsstrasse 16, CH-8092 Zurich, Switzerland; Department of Geological Sciences, Land Use and Environmental Change Institute (LUECI), University of Florida, 441 Williamson Hall, Gainesville, FL 32611, United States; Institut Forel, Department of Geology and Paleontology, University of Geneva, Geneva, Switzerland 3 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84884525372&doi=10.2204%2fiodp.sd.3.02.2006&partnerID=40&md5=3e5fdc811aad31789ba62861eeea668d cited By 23 D. Hodell F. Anselmetti M. Brenner D. Ariztegui G. Alfaro J. Blijdenstein C. Bronnimann K. Brady M. Bush E. Chapron J. Curtis E. Endsley J. Escobar C. Gallup V. Gamble A. Gilli S. Girardclos D. Grzesik R. Hofmann G. Islebe A. Mueller A. Noren L. Pérez F. Thevenon article Boness2006825 We present shear velocity anisotropy data from crustal earthquakes in California and demonstrate that it is often possible to discriminate structural anisotropy (polarization of the shear waves along the fabric of major active faults) from stress-induced anisotropy (polarization parallel to the maximum horizontal compressive stress). Stress directions from seismic stations located near (but not on) the San Andreas fault indicate that the maximum horizontal compressive stress is at a high angle to the strike of the fault. In contrast, seismic stations located directly on one of the major faults indicate that shear deformation has significantly altered the elastic properties of the crust, inducing shearwave polarizations parallel to the fault plane. © 2006 Geological Society of America. 2006 English 00917613 10.1130/G22309.1 Geology 34 825-828 Department of Geophysics, Stanford University, Stanford, CA 94305, United States; Chevron, 6001 Bollinger Canyon Road, San Ramon, CA 94583, United States 10 Crustal stress; San Andreas fault; Seismic anisotropy, Anisotropy; Compressive stress; Earthquakes; Mapping; Seismic waves; Shear stress; Tectonics, Structural geology, active fault; deformation mechanism; earthquake; elastic property; fault plane; polarization; S-wave; San Andreas Fault; seismic anisotropy, California; North America; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-33750085990&doi=10.1130%2fG22309.1&partnerID=40&md5=4a28fcd66966b78cbc933c6db7ae10d3 cited By 144 N.L. Boness M.D. Zoback article demory2006xrf 2006 GFZ Data Services François Demory Hedi Oberhänsli N Nowaczyk Matthias Gottschalk R Wirth R Naumann conference Paul20062965 This paper presents a wellbore stability study of the SAFOD (San Andreas Fault Observatory at Depth) research borehole at Parkfield, central California. In the summer of 2005, the SAFOD borehole was successfully drilled through the San Andreas Fault (SAF) in an area characterized by fault creep and frequent microearthquakes. In this study we report how the analysis of wellbore failures in the upper part of the hole, geophysical logs and a model for stress gradients in the vicinity of the fault were used to estimate the mud weights required to successfully drill through the fault. Logging-while-drilling acoustic caliper data and real-time hole volume calculations both show that relatively little failure occurred while passing through the SAF. Thus, the predicted mud weight was successful in drilling a stable borehole. However, a six-arm ealiper log run after drilling was completed indicates that there was deterioration of the borehole with time. We suspeet this was caused by failures along the weak bedding planes around the borehole, exacerbated by fluid penetration and key seating. Copyright 2006, Society of Petroleum Engineers. 2006 English 10.2523/102781-ms Proceedings - SPE Annual Technical Conference and Exhibition 5 Society of Petroleum Engineers (SPE) 2965-2976 SPE, Stanford U., United States Creep; Oil well drilling; Real time systems; Well logging, Bedding planes; Microearthquakes; San Andreas Fault (SAF); Stress gradients, Boreholes https://www.scopus.com/inward/record.uri?eid=2-s2.0-33751005598&doi=10.2523%2f102781-ms&partnerID=40&md5=f267b3c8392551ff275c374521cec307 cited By 1 P. Paul M. Zoback article Sun20063506 Seismic waves in a porous medium experience attenuation and velocity dispersion. In conventional seismic data processing, velocity dispersion is neglected partially because of insufficient or inconclusive observations. In a medium of high attenuation (Q<30), velocity dispersion is a concern. In order to detect velocity dispersion in the exploration seismic frequency band, uncorrelated Vibroseis data were utilized. We have simulated distortion of the correlation wavelet of Vibroseis data due to velocity dispersion to investigate how dispersion distorts Vibroseis data. Different methods were investigated to develop a robust method to detect and measure velocity dispersion in uncorrelated Vibroseis data. Using the CCMW (cross-correlation with a moving window) method, small velocity variations as a function of frequency were observed in the borehole Vibroseis data from the Mallik gas hydrate research wells (Mackenzie Delta, NWT, Canada). © 2005 Society of Exploration Geophysicists. 2006 English 9781604236972 10523812 10.1190/1.2370264 SEG Technical Program Expanded Abstracts 25 Society of Exploration Geophysicists 3506-3510 University of Toronto, Toronto, ON, Canada 1 Data handling; Gas hydrates; Petroleum prospecting; Porous materials; Seismic prospecting; Seismic waves; Seismology; Velocity, Cross correlations; Function of frequency; Moving window; Robust methods; Seismic data processing; Seismic frequencies; Velocity dispersion; Velocity variations, Dispersion (waves) https://www.scopus.com/inward/record.uri?eid=2-s2.0-33845403051&doi=10.1190%2f1.2370264&partnerID=40&md5=39f504c42301ad948ca264a852fc8e1e cited By 5 L.F. Sun B. Milkereit article Wicks200672 The Yellowstone caldera, in the western United States, formed ∼640,000 years ago when an explosive eruption ejected ∼1,000 km3 of material. It is the youngest of a series of large calderas that formed during sequential cataclysmic eruptions that began ∼16 million years ago in eastern Oregon and northern Nevada. The Yellowstone caldera was largely buried by rhyolite lava flows during eruptions that occurred from ∼150,000 to ∼70,000 years ago. Since the last eruption, Yellowstone has remained restless, with high seismicity, continuing uplift/subsidence episodes with movements of ∼70 cm historically to several metres since the Pleistocene epoch, and intense hydrothermal activity. Here we present observations of a new mode of surface deformation in Yellowstone, based on radar interferometry observations from the European Space Agency ERS-2 satellite. We infer that the observed pattern of uplift and subsidence results from variations in the movement of molten basalt into and out of the Yellowstone volcanic system. © 2006 Nature Publishing Group. 2006 English 00280836 10.1038/nature04507 Nature 440 Nature Publishing Group 72-75 US Geological Survey, MS 977, Menlo Park, CA 94555, United States; US Geological Survey, David A. Johnston Cascades Volcano Observatory, Bldg. 10, 1300 SE Cardinal Court, Vancouver, WA 98683, United States 7080 Earthquakes; Interferometry; Radar; Satellites, Cataclysmic eruptions; Hydrothermal activity, Volcanoes, caldera; crustal deformation; igneous intrusion; uplift, analytic method; article; interferometer; priority journal; surface property; telecommunication; thermal analysis; volcano, North America; United States; Wyoming; Yellowstone Caldera https://www.scopus.com/inward/record.uri?eid=2-s2.0-33644773463&doi=10.1038%2fnature04507&partnerID=40&md5=f5fbd6dab6a6403b0d391723bd5829a1 cited By 128 C.W. Wicks W. Thatcher D. Dzurisin J. Svarc article Xiao2006443 In order to reconstruct the formation and exhumation mechanisms of UHP metamorphic terrains, the Chinese Continental Scientific Drilling Program (CCSD) has been carried out in Donghai of the Dabie-Sulu ultrahigh-pressure (UHP) metamorphic belt, East China. Eclogite, gneiss, amphibolite (retrograded from eclogite), ultramafic rocks, and minor schist and quartzite have been drilled. Aiming to reveal the fluid behaviour in a vertical sequence of an UHP slab, we investigated fluid inclusion and oxygen isotope characteristics of selected drillcores from the main hole and the pilot-holes PP2 and ZK 703 of the CCSD. More than 540 laser-ablation oxygen isotope analyses on garnet, omphacite, quartz, kyanite, amphibole, phengite, rutile, epidote, amphibole, plagioclase, and biotite from various rocks in the depth range of 0-3,000 m (mainly eclogite and gneiss) show that the investigated rocks can be divided into two groups: 18O-depleted rocks (as low as δ18O = -7.4‰ for garnet) indicate interaction with cold climate meteoric waters, whereas 18O-normal rocks (with bulk δ18O > +5.6‰) have preserved the O-isotopic compositions of their protoliths. Meteoric water/rock interaction has reached depths of at least 2,700 m. Oxygen isotope equilibrium has generally been achieved. Isotopic compositions of mineral phases are homogeneous on a mm to cm scale regardless of lithology, but heterogeneous on the scale of a few metres. Oxygen isotope distributions in the vertical sections favour an "in situ" origin of the UHP metamorphic rocks. The very negative δ18O eclogites usually have higher hydroxyl-mineral contents than the normal δ18O rocks, indicating higher water content during UHP metamorphism. Fluid inclusion data suggest that rocks with depleted 18O compositions have had different fluid histories compared to those with normal δ18O values. Rocks with depleted 18O mainly have primary medium-to-high salinity inclusions in omphacite, kyanite and quartz, and abundant secondary low-salinity or pure water inclusions in quartz, indicating a high-salinity-brine-dominated fluid system during peak UHP metamorphism; no carbonic inclusions have been identified in these rocks. By contrast, primary very high-density CO2 inclusions are commonly found in the rocks with normal δ18O values. These observations suggest that fluid and oxygen isotope composition of minerals are related and reflect variable degrees of alterations of the Dabie-Sulu UHP metamorphic rocks. © Springer-Verlag 2006. Article 2006 English 00107999 10.1007/s00410-006-0084-5 Contributions to Mineralogy and Petrology 152 443 – 458 4 Asia; China; Dabie-Sulu Belt; Donghai; Eurasia; Far East; Jiangsu; fluid inclusion; isotopic composition; metamorphic rock; mineralogy; oxygen isotope; ultrahigh pressure metamorphism https://www.scopus.com/inward/record.uri?eid=2-s2.0-33748658215&doi=10.1007%2fs00410-006-0084-5&partnerID=40&md5=9fe2bb64a21d471eb627de6dee7b927b Cited by: 58 Yilin Xiao Zeming Zhang Jochen Hoefs Alfons Kerkhof article Zhang2006421 The main hole (MH) of the Chinese Continental Scientific Drilling Project (CCSD) in southern Sulu has penetrated into an ultrahigh-pressure (UHP) metamorphic rock slice which consists of orthogneiss, paragneiss, eclogite, ultramafic rock and minor schist. Recovered eclogites have a UHP metamorphic mineral assemblage of garnet + omphacite + rutile ± phengite ± kyanite ± coesite ± epidote. Ultramafic rocks contain garnet + olivine + clinopyroxene + orthopyroxene ± Ti-clinohumite ± phlogopite. Gneisses and schists contain an amphibolite-facies paragenesis, but their zircons have coesite, garnet, omphacite (or jadeite) and phengite inclusions, indicating that eclogites and gneisses have been subjected to in situ UHP metamorphism. Using available geothermobarometers, P-T estimates of 3.1-4.4 GPa and 678-816°C for eclogites were obtained. If surface outcrops and neighboring shallow drill holes are considered together, we suggest that a huge supracrustal rock slab (> 50 km long × > 100 km wide × 5 km deep) was subducted to a depth > 100 km and then exhumed to the surface. The depth interval (0-2,050 m) of the CCSD-MH can be divided into six lithological units. Unit 1 consists of alternating layers of quartz-rich and rutile-rich eclogites, with thin interlayers of gneiss and schist. Eclogites of unit 1 are characterized by Nb, Ta, Sr and Ti depletions, low Mg number and general LREE enrichment. Unit 2 comprises rutile- and ilmenite-rich eclogite and minor "normal" eclogite and is characterized by high TiO2, total Fe, V, Co and Sr, and very low SiO2, alkali, Zr, Ba, Nb, Ta and total REE contents, and LREE-depleted REE patterns with slightly positive Eu anomalies. Unit 3 contains ultramafic rock and minor MgO-rich eclogite. Protoliths of UHP rocks from units 1, 2 and 3 represent a layered mafic to ultramafic intrusion at crustal depth. Units 4 and 6 consist of interlayered eclogite and paragneiss; the eclogites are characterized by Th, U, Nb, Ta and Ti depletion and K enrichment and LREE-enriched REE patterns. Paragneisses show Nb, Ta, Sr and Ti depletions and LREE-enriched REE patterns occasionally with slightly negative Eu anomalies, indicating that their protoliths represent metamorphic supracrustal series. Unit 5 consists mainly of orthogneisses, showing distinct Nb, Ta, Sr and Ti depletions, and LREE-enriched REE patterns with pronounced negative Eu anomalies, suggesting granitic protoliths. In conclusion it is proposed that the southern Sulu UHP belt consists of a series of meta-supracrustal rocks, a layered mafic-ultramafic complex and granites. © Springer-Verlag 2006. Article 2006 English 00107999 10.1007/s00410-006-0120-5 Contributions to Mineralogy and Petrology 152 421 – 441 4 Asia; China; Eurasia; Far East; Sulu Belt; amphibolite facies; chemical composition; geochemistry; metamorphic rock; P-T conditions; paragenesis; petrology; supracrustal rock; ultrahigh pressure metamorphism https://www.scopus.com/inward/record.uri?eid=2-s2.0-33748653345&doi=10.1007%2fs00410-006-0120-5&partnerID=40&md5=4f524149810f84d88b93f16a32c8a8eb Cited by: 95 Zeming Zhang Yilin Xiao Jochen Hoefs J.G. Liou Klaus Simon article Ziatdinov20063240 We apply tube-wave monitoring method to a time-lapse cross-well dataset from Mallik field. Raw waveforms are used for analysis thus avoiding any smearing of 4D response introduced by pre-processing. We perform extensive modeling that includes effects of a source borehole and confirms nature of most prominent arrivals as being tube-wave related. Modeling proves that strongest conversion of tube wave into P and S waves occurs at the sharp acoustic boundary. Data displays clear time-lapse changes in tube-wave related arrivals, while shows no change in first arrivals. Modeling suggests that to explain the data the reservoir changes have to occur at a deeper interval than previously anticipated, below the perforations. Excellent agreement between modeled and experimental data provides us with good confidence in our results. This study represents first application of tube-wave monitoring concept. © 2005 Society of Exploration Geophysicists. 2006 English 9781604236972 10523812 10.1190/1.2370203 SEG Technical Program Expanded Abstracts 25 Society of Exploration Geophysicists 3240-3244 St. Petersburg State University, St. Petersburg, Russian Federation; Shell International Exploration and Production Inc.; Lawrence Berkeley National Laboratory, Berkeley, CA, United States 1 Geophysical prospecting; Shear waves; Tubes (components), Cross-well; Data display; First arrival; P- and S-waves; Pre-processing; Time-lapse response; Tube waves; Wave forms, Acoustics https://www.scopus.com/inward/record.uri?eid=2-s2.0-33845463217&doi=10.1190%2f1.2370203&partnerID=40&md5=8a74c477a4012d871d742f04bbd8a2e4 cited By 0 S. Ziatdinov A. Bakulin B. Kashtan V. Korneev A. Sidorov article Krüger20061978 This work is inspired by the observation, that gas hydrate bearing sediments have a high velocity in combination with high attenuation. We study numerically the influence of different gas hydrate locations within the pore space on transmitted p-waves. From the wave propagation simulations on the micro-scale it can be seen, that different positions of the gas hydrate in the pore space results in almost the same effective velocities and attenuation, as long as the gas hydrate had contact to the sediment grains. This changes in the case of a suspension, here the attenuation increases and the effective velocity decreases. The resulting p-wave versus gas hydrate saturation plot is in a qualitatively good agreement with experimental results obtained for the Mallik 2L-38 well. © 2005 Society of Exploration Geophysicists. 2006 English 9781604236972 10523812 10.1190/1.2369921 SEG Technical Program Expanded Abstracts 25 Society of Exploration Geophysicists 1978-1982 Freie Universität Berlin, Berlin, Germany 1 Gases; Geophysical prospecting; Hydration; Petroleum prospecting; Seismic waves; Wave propagation, Effective velocity; Gas hydrate bearing sediments; Gas hydrate saturations; High velocity; Micro-scale; Pore space; Sediment grains; Wave propagation simulation, Gas hydrates https://www.scopus.com/inward/record.uri?eid=2-s2.0-33845405489&doi=10.1190%2f1.2369921&partnerID=40&md5=3a960e7b27eedab643519466e4098252 cited By 0 O.S. Krüger E.H. Saenger S.A. Shapiro article Ratschbacher200645 There are three sutures in the Qinling-Dabie-Sulu orogen in the Tongbai-Xinxian (northern Hong'an)-northern Dabie area: the Silurian Sino-Korean craton-Erlangping intra-oceanic arc suture, the Silurian Erlangping arc-Qinling unit (microcontinent) suture, and the Early Triassic Qinling unit-Yangtze craton suture. We resolve the controversy regarding the age of the Sino-Korean craton-Yangtze craton collisionby recognizing that there was Paleozoic collision between the Qinling unit and the Sino-Korean craton and Mesozoic collision between the Qinling unit and the Yangtze craton. The Qinling unit constitutes a long and narrow microcontinent that extends through the Qinling-Dabie area and probably into the Sulu area. Its common characteristics are the Mesoproterozoic (ca. 1.0 Ga) Jinningian orogeny, ca. 0.8-0.7 Ga arc formation and rifting, and Late Silurian-Early Devonian (ca. 400 Ma) arc magmatism with concomitant regional contact metamorphism up to granulite-facies conditions (peak: 680-740 °C at 0.9-1.1 GPa). A common Proterozoic history links the Qinling microcontinent to the Yangtze craton. Its 400 Ma arc, forearc basin, and its separation from the Yangtze craton by the partly oceanic Huwan mélange make the Qinling microcontinent distinct. The forearc basin sits on the southern part of the 400 Ma arc and underlying Proterozoic continental basement, and detrital geochronology ties it to the Qinling microcontinent basement and its arc. The Huwan mélange is a subduction-accretion complex containing elements of the Qinling microcontinent and its arc, the Paleotethyan ocean floor, and possibly the Yangtze craton. Quartz eclogites (540-590 °C, 2.1 GPa) signify ca. 315 Ma subduction. Devonian to Permian eclogite zircon ages, 40 Ar/ 39 Ar and Rb/Sr mineral ages in the forearc and its basement, and static, Permian blueschist metamorphism in the upper-plate basement testify to subduction throughout the late Paleozoic. The ̃10-km-wide Huwan detachment bounds the high- and ultrahigh-pressure rocks of the Xinxian-Hong'an block (pressure peak at older than 240 Ma) along their northern margin. It is partly responsible for exhumation of the high- and ultrahighpressure rocks, but the entire basement core of Hong'an-Dabie orogen is also strongly deformed. The Huwan shear-zone high-strain deformation indicates passage of rocks through the lithosphere by subhorizontal N-S extension and vertical contraction, showcased by condensed Triassic isograds (420 °C and ̃0.4 GPa in the hanging wall and ̃530 °C and 2.2 GPa in the footwall). The Huwan detachment produced Triassic crustal exhumation rates of 1.9-1.4 mm/yr; synkinematic phengite grew as early as ca. 235 Ma, and the main retrograde deformation occurred at 224-195 Ma. The Tongbai-Xinxian area shows a massive 130-115 Ma cluster of cooling ages, reflecting regional cooling after granitoid injection and regional Cretaceous heating. Apatite fission-track ages cluster at 80-55 Ma and signify cooling related to transtension that coincided with rifting marked by Late Cretaceous-Eocene red bed deposition throughout eastern China. Exhumation rates of for the last 70 m.y. have been slow: ̃0.06 mm/yr. The India-Asia collision reactivated the orogen in the Eocene, particularly along the Tanlu fault zone and locally along fault zones in Tongbai-Xinxian. © 2006 Geological Society of America. Article 2006 English 00721077 10.1130/2006.2403(03) Special Paper of the Geological Society of America 403 Geological Society of America 45 – 75 China; Dabie Mountains; Henan; Tongbai; Xinxiang; Cooling; Deformation; Fission reactions; Geochronology; Metamorphic rocks; Phosphate minerals; Silicate minerals; Structural geology; Zircon; Holocenes; Huwan detachment; Qinling-dabie-sulu orogen; Sino-korean-yangtze suture; Ultrahigh pressure; exhumation; orogeny; Paleozoic; suture zone; Tertiary; ultrahigh pressure metamorphism; Buildings https://www.scopus.com/inward/record.uri?eid=2-s2.0-34248517036&doi=10.1130%2f2006.2403%2803%29&partnerID=40&md5=da0b4d9312955600d743bad36706d64f Cited by: 222 Lothar Ratschbacher Leander Franz Eva Enkelmann Raymond Jonckheere Axel Pörschke Bradley R. Hacker Shuwen Dong Yueqiao Zhang article Onstott2006369 Water residing within crustal fractures encountered during mining at depths greater than 500 meters in the Witwatersrand basin of South Africa represents a mixture of paleo-meteoric water and 2.0–2.3 Ga hydrothermal fluid. The hydrothermal fluid is highly saline, contains abiogenic CH4 and hydrocarbon, occasionally N2, originally formed at ∼250–300◦C and during cooling isotopically exchangedO and Hwith minerals and accrued H2,4He and other radiogenic gases. The paleo-meteoric water ranges in age from ∼10 Ka to &gt;1.5 Ma, is of low salinity, falls along the global meteoric water line (GMWL) and is CO2 and atmospheric noble gas-rich. The hydrothermal fluid, which should be completely sterile, has probably been mixing with paleo-meteoric water for at least the past∼100 Myr, a process which inoculates previously sterile environments at depths &gt;2.0 to 2.5 km. Free energy flux calculations suggest that sulfate reduction is the dominant electron acceptor microbial process for the high salinity fracture water and that it is 107 times that normally required for cell maintenance in lab cultures. Flux calculations also indicate that the potential bioavailable chemical energy increases with salinity, but because the fluence of bioavailable C, N and P also increase with salinity, the environment remains energy-limited. The4He concentrations and theoretical calculations indicate that the H2 that is sustaining the subsurface microbial communities (e.g. H2-utilizing SRB and methanogens) is produced by water radiolysis at a rate of ∼1nMyr−1. Microbial CH4 mixes with abiogenicCH4 to produce the observed isotopic signatures and indicates that the rate of methanogenesis diminishes with depth from∼100 at&lt;1 kmbls, to&lt;0.01nMyr−1 at&gt;3 kmbls. Microbial Fe(III) reduction is limited due to the elevated pH. The δ13C of dissolved inorganic carbon is consistent with heterotrophy rather than autotrophy dominating the deeper, more saline environments. One potential source of the organic carbon may be microfilms present on the mineral surfaces. © Taylor &amp; Francis. 2006 English 01490451 10.1080/01490450600875688 Geomicrobiology Journal 23 369-414 Department of Geosciences, Princeton University, Princeton, NJ, United States; Department of Geology, University of Toronto, Toronto, ON, Canada; Geoforschungszentrum Potsdam, Potsdam, Germany; Department of Geological Sciences, Biogeochemical Laboratorie, Indiana University, Bloomington, IN, United States; Analysis University of Tennessee, Knoxville, TN, United States; Environmental Microbiology Group, Pacific Northwest National Laboratory, Richland, WA, United States; New Mexico Institute of Mining and Technology, Department of Biology, Socorro, NM, United States; Oak Ridge National Laboratory, Oak Ridge, TN, United States; Department of Microbial, Biochemical and Food Biotechnology, Faculty of Science, University of the Free State, Bloemfontein, Free State, South Africa; Geosyntec, Princeton, NJ, United States; Shaw Environmental, Lawrenceville, NJ, United States; Department of Earth Sciences, The University of Western Ontario, London, ON, N6A 5B7, Canada 6 biogeochemistry; dissolved inorganic carbon; groundwater; methanogenesis; microbial community; sulfate-reducing bacterium, Africa; South Africa; Southern Africa; Sub-Saharan Africa; Witwatersrand, Methanobacteriales https://www.scopus.com/inward/record.uri?eid=2-s2.0-67349125827&doi=10.1080%2f01490450600875688&partnerID=40&md5=ad063d82a6eac2a8cc0237985bb395ea cited By 33 T.C. Onstott L.-H. Lin M. Davidson B. Mislowack M. Borcsik J. Hall G. Slater J. Ward B. Sherwoodlollar J. Lippmann-Pipke E. Boice L.M. Pratt S. Pfiffner D. Moser T. Gihring T.L. Kieft T.J. Phelps E. Vanheerden D. Litthaur M. DeFlaun R. Rothmel G. Wanger G. Southam article Schulte200677 Two cores from Brazos, Texas, spanning the Cretaceous-Paleogene (K-P) boundary, are investigated by a multidisciplinary approach aiming at unraveling environmental changes and sequence stratigraphic setting. In addition, the sedimentology of the K-P event deposit and its correlation with the K-P boundary is studied. Foraminifera and nannofossil stratigraphy indicates that both cores include a latest Maastrichtian (Zone CF1-CF2) and earliest Danian (P0, Pα and P1a) shale sequence with a sandy and Chicxulub ejecta-bearing event deposit at the K-P boundary; a hiatus of unknown duration may be present by the unconformable base of the event deposit. Planktic foraminifera as well as calcareous nannofossil abundance and diversity both decline abruptly above the event deposit (K-P mass extinction), whereas benthic foraminifera show a pronounced faunal change but no mass extinction. Mineralogical and geochemical proxies suggest that-except for the sandwiched K-P event deposit-no facies change took place across the K-P boundary and no evidence for adverse an- or dysoxic sedimentary conditions following the Chicxulub impact was observed. Therefore, the interval bracketing the K-P event deposit is considered as highstand systems tract. Increased coarse detritus input and low planktic/benthic (P/B) foraminifera ratios during the earliest Paleocene (P0 and Pα) both suggest an increased coastal proximity or relative sea-level lowering, although the K-P mass extinction of planktic foraminifera might have influenced the P/B ratios as well. Consequently, the sandy shales of the early Paleocene are considered as late regressive highstand or as lowstand deposit. During P1a, shales assigned as transgressive systems tract overlie a pyrite- and glauconite-rich bioturbated transgressive surface or type-2-sequence boundary. The smectite-dominated clay assemblage, with minor illite, kaolinite and chlorite indicates semiarid-humid climates with no obvious shifts across the K-P boundary. The magnetic susceptibility signature during the Maastrichtian reveals a subtle cyclic (or rhythmic) pattern, whereas a high-amplitude cyclic pattern is present during the early Danian. The K-P event deposit shows a succession of high-energetic debris flows and turbidites derived from multiple source areas, followed by a period of decreasing current energy. Deposition was likely triggered by multiple tsunami or tempestites followed by a prolonged period of reworking and settling. The Chicxulub ejecta at the base of the K-P event deposit consists of Mg-rich smectite-as well as Fe-Mg-rich chlorite-spherules. Their mineralogical composition points to target rocks of mafic to intermediate composition, presumably situated in the northwestern sector of the Chicxulub impact structure. Besides these silicic phases, the most prominent ejecta components are limestone clasts, accretionary carbonate clasts, and microspar, suggesting that the Texas area received ejecta also from shallow, carbonate-rich lithologies at the impact site on the Yucatán carbonate platform. The excellent correlation of Chicxulub ejecta at Brazos with ejecta found in the K-P boundary layer worldwide - along with the associated mass extinction - provides no evidence that Chicxulub predated the K-P boundary and allows for unequivocal positioning of the K-P boundary at the event deposit. © 2005 Elsevier B.V. All rights reserved. 2006 10.1016/j.sedgeo.2005.09.021 Sedimentary Geology 184 77-109 Institut für Geologie und Mineralogie, Universität Erlangen-Nürnberg, Schloßgarten 5, D-91054 Erlangen, Germany; Department of Geography and Geology, KU Leuven, Redingenstraat 16, B-3000 Leuven, Belgium; Fachbereich 5 Geowissenschaften, Universität Bremen, Postfach 330440, D-28334 Bremen, Germany; Geologisch-Paläontologisches Institut, Universität Heidelberg, Im Neuenheimer Feld 234, D-69120 Heidelberg, Germany 1-2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-30544436024&doi=10.1016%2fj.sedgeo.2005.09.021&partnerID=40&md5=ae84c8ae9b470412e3317b98474a2db2 cited By 80 P. Schulte R. Speijer H. Mai A. Kontny article Wittmann2006433 To ascertain the progressive stages of shock metamorphism of zircon, samples from three well-studied impact craters were analyzed by optical microscopy, scanning electron microscopy (SEM), and Raman spectroscopy in thin section and grain separates. These samples are comprised of well-preserved, rapidly quenched impactites from the Ries crater, Germany, strongly annealed impactites from the Popigai crater, Siberia, and altered, variably quenched impactites from the Chicxulub crater, Mexico. The natural samples were compared with samples of experimentally shock-metamorphosed zircon. Below 20 GPa, zircon exhibits no distinct shock features. Above 20 GPa, optically resolvable planar microstructures occur together with the high-pressure polymorph reidite, which was only retained in the Ries samples. Decomposition of zircon to ZrO2 only occurs in shock stage IV melt fragments that were rapidly quenched. This is not only a result of post-shock temperatures in excess of ∼1700 °C but could also be shock pressure-induced, which is indicated by possible relics of a high-pressure polymorph of ZrO2. However, ZrO2 was found to revert to zircon with a granular texture during devitrification of impact melts. Other granular textures represent recrystallized amorphous ZrSiO4 and reidite that reverted to zircon. This requires annealing temperatures &gt;1100 °C. A systematic study of zircons from a continuous impactite sequence of the Chicxulub impact structure yields implications for the post-shock temperature history of suevite-like rocks until cooling below ∼600 °C. © The Meteoritical Society, 2006. 2006 10.1111/j.1945-5100.2006.tb00472.x Meteoritics and Planetary Science 41 433-454 Institut für Mineralogie, Museum für Naturkunde, Humboldt Universität zu Berlin, Invalidenstrasse 43, 10115 Berlin, Germany 3 https://www.scopus.com/inward/record.uri?eid=2-s2.0-33646128493&doi=10.1111%2fj.1945-5100.2006.tb00472.x&partnerID=40&md5=1f310cdafabe6c7a667799c9e01ebc27 cited By 131 A. Wittmann T. Kenkmann R.T. Schmitt D. Stöffler article sd-2-17-2006 2006 10.2204/iodp.sd.2.04.2006 Scientific Drilling 2 17-19 https://sd.copernicus.org/articles/2/17/2006/ C. A. Scholz A. S. Cohen T. C. Johnson J. W. King K. Moran article Scheu2006136 Laboratory measurements of elastic properties of volcanic rocks are crucial for the modelling of volcano seismic activity. Compared to the large database reported in the literature for sedimentary, igneous and metamorphic rocks, the data set for volcanic rocks is limited and mostly restricted to basalts. Data for more silica-rich rocks are sparse. In particular, velocity data for silica-rich volcanic rocks measured at elevated temperature are lacking. We measured the elastic P- and S-wave velocities and the velocity anisotropy of porous dacitic rocks from Unzen Volcano, Japan, exhibiting an open porosity of 3.3 to 24.3 vol.%. The measurements were done at temperatures of up to 600 °C and confining pressures of 100 MPa, corresponding to depths of ∼ 3000-4000 m. Samples with even higher porosities failed at the required pressures. The measurements were carried out in a cubic multi-anvil pressure apparatus, using the pulse transmission technique. In contrast to low-porosity magmatic and metamorphic rocks, the seismic velocities of the investigated volcanic rocks increased and the velocity anisotropies decreased with increasing temperature, due to further sample compaction. There is a close relationship between velocity, density and porosity. The higher the density (and the lower the porosity) the higher are the P- and S-wave velocities. These results can contribute to a better understanding of the propagation of seismic energy through the volcanic edifice. © 2005 Elsevier B.V. All rights reserved. 2006 English 03770273 10.1016/j.jvolgeores.2005.08.007 Journal of Volcanology and Geothermal Research 153 136-147 Department of Earth and Environmental Sciences, University of Munich, Theresienstr. 41 /III, 80333 Munich, Germany; Institut für Geowissenschaften der Universität Kiel, Olshausenstr. 40-60, 24098 Kiel, Germany 1-2 SPEC. ISS. Anisotropy; High temperature effects; Metamorphic rocks; Porosity; Seismology; Volcanic rocks; Volcanoes, Pulse transmission technique; Silica-rich rocks; Volcano seismic activity, Elastic waves, dacite; elasticity; high temperature; P-wave; S-wave; seismic anisotropy; seismology; volcanic rock; volcanology, Asia; Eurasia; Far East; Japan; Kyushu; Nagasaki [Kyushu]; Unzen Volcano https://www.scopus.com/inward/record.uri?eid=2-s2.0-33747799611&doi=10.1016%2fj.jvolgeores.2005.08.007&partnerID=40&md5=7bde461b30d7402c9e5ff902a61c1c31 cited By 29 B. Scheu H. Kern O. Spieler D.B. Dingwell article Kenkmann200615 Subhorizontal shear planes (detachments) are observed in bedded limestones in the periphery of the Ries impact crater, Germany. These detachments occur at 0.8-1.8 crater radii distance from the crater center beneath deposits of the continuous ejecta blanket. Striations on detachment planes and offsets of markers indicate top-outward shearing with radial slip vectors. Detachments were found at depths between a few meters and more than 50 m beneath the target surface. The displacements along these faults range from meters to decameters and decrease with increasing depth and distance from the crater center. With increasing crater distance, detachment horizons tend to climb to shallower levels. Cross-cutting relationships to faults associated with the crater collapse indicate that detachment faulting started prior to the collapse but continued during crater modification. Numerical modeling of the cratering process shows that near-surface deformation outside the transient crater is induced by two separate mechanisms: (i) weak spallation by interference of shock and release waves near the target surface and (ii) subsequent dragging by the deposition of the ejecta curtain. Spallation causes an upward and outward directed motion of target material that increases in magnitude toward the target surface. It leads to decoupling of the uppermost target layers in the early cratering stage without totally disintegrating the rock. The subsequent arrival of the oblique impact shower of the ejecta curtain at the target surface delivers a horizontal momentum to the uppermost target area and results in a second horizontal displacement increment by dragging. With increasing depth this effect vanishes rapidly. Spallation decoupling and subsequent ejecta dragging of near-surface rocks is probably a general cratering mechanism around craters in layered targets with weak interbeds. © 2006 Elsevier B.V. All rights reserved. 2006 10.1016/j.epsl.2006.08.024 Earth and Planetary Science Letters 252 15-29 Museum of Natural History-Mineralogy, Humboldt-University Berlin, Invalidenstrasse 43, D-10115 Berlin, Germany; Institute for Geodynamics and Geospheres, Russian Academy of Science, Leninsky Prospect, 38, 119334 Moscow, Russian Federation 1-2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-33750974452&doi=10.1016%2fj.epsl.2006.08.024&partnerID=40&md5=0f33c623b6d4da912e5a54b0ff9f9698 cited By 30 T. Kenkmann B.A. Ivanov article Hole2006 Refraction traveltimes from a 46-km long seismic survey across the San Andreas Fault were inverted to obtain two-dimensional velocity structure of the upper crust near the SAFOD drilling project. The model contains strong vertical and lateral velocity variations from <2 km/s to ∼6 km/s. The Salinian terrane west of the San Andreas Fault has much higher velocity than the Franciscan terrane east of the fault. Salinian basement deepens from 0.8 km subsurface at SAFOD to ∼2.5 km subsurface 20 km to the southwest. A strong reflection and subtle velocity contrast suggest a steeply dipping fault separating the Franciscan terrane from the Great Valley Sequence. A low-velocity wedge of Cenozoic sedimentary rocks lies immediately southwest of the San Andreas Fault. This body is bounded by a steep fault just northeast of SAFOD and approaches the depth of the shallowest earthquakes. Multiple active and inactive fault strands complicate structure near SAFOD. Copyright 2006 by the American Geophysical Union. 2006 English 00948276 10.1029/2005GL025194 Geophysical Research Letters 33 Department of Geosciences, Virginia Polytechnic Institute and State University, 4044 Derring Hall, Blacksburg, VA 24061, United States; GeoForschungsZentrum, Telegrafenberg E322, D-14471 Potsdam, Germany; U. S. Geological Survey, 345 Middlefield Rd., Menlo Park, CA 94025, United States; Department of Earth and Environmental Sciences, University of Munich, Theresienstr. 41, D-80333 Munich, Germany 7 Acoustic wave refraction; Earthquakes; Sedimentary rocks; Seismic prospecting; Seismic waves; Two dimensional; Velocity, San Andreas fault zone; Seismic refraction, Seismology, fault zone; San Andreas Fault; seismic refraction; seismic survey; travel time; upper crust https://www.scopus.com/inward/record.uri?eid=2-s2.0-33646833994&doi=10.1029%2f2005GL025194&partnerID=40&md5=034d6a648cf52cf2f4bd38269408e102 cited By 61 J.A. Hole T. Ryberg G.S. Fuis F. Bleibinhaus A.K. Sharma article Malin2006 Fault-guided waves reveal a low-velocity fault segment a few hundred meters southwest of the main strand of the San Andreas Fault (SAf) system. In 2004, the San Andreas Fault Observatory at Depth (SAFOD) Main Hole was drilled 2.5 km underground and 0.7 km west of the SAF surface trace. A 3-component, 4.5-Hz seismograph was installed near the bottom of this hole. This instrument recorded fault zone guided (Fg) waves originating from earthquakes along the main SAF ∼2 km north and 3 km south of the SAFOD site. This ∼5 km length corresponds to a distinctive low-velocity structure imaged in 2003 using microearthquakes recorded on the Pilot Hole array. Because this structure transmits Fg-waves from the main fault, it is probably connected to the main SAF and is most likely a major, unmapped fault. Copyright 2006 by the American Geophysical Union. 2006 English 00948276 10.1029/2006GL025973 Geophysical Research Letters 33 Nicholas School of the Environment and Earth Sciences, Division of Earth and Ocean Sciences, Duke University, Durham, NC, United States; Division of Earth and Ocean Sciences, Nicholas School of the Environment and Earth Sciences, Duke University, Durham, NC 27708-0235, United States 13 Conformal mapping; Drilling; Seismic waves; Seismographs; Tomography; Velocity measurement, Fault-guided wave mapping; Low-velocity fault; Surface trace, Structural geology, earthquake; fault; fault zone; P-wave; San Andreas Fault; seismograph; tomography, California; North America; San Andreas; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-33750074815&doi=10.1029%2f2006GL025973&partnerID=40&md5=1644d238d9d8e1a7746d1a5cfe075c3d cited By 19 P. Malin E. Shalev H. Balven C. Lewis-Kenedi article Bohnhoff2006373 We investigate aftershock focal mechanisms of the Mw=7.4 Izmit earthquake of 1999 August 17, on the western North Anatolian fault zone (NAFZ). Spatial clustering and the orientation of 446 fault plane solutions are analysed. The Izmit mainshock occurred as a right-lateral slip on an EW-trending near-vertical fault plane. Aftershock clusters define four individual fault segments. Focal mechanisms surrounding the epicentres of the Izmit and subsequent Düzce mainshock (Mw= 7.1, 1999 November 12) indicate predominantly strike-slip but also normal faulting. Aftershocks in the area between the Izmit and Düzce segments are mainly related to EW-oriented normal faulting delineating a small pull-apart structure. Beneath the easternmost Sea of Marmara, alignments of aftershocks suggest branching of the NAFZ into three or more active segments that differ significantly in terms of their focal mechanism characteristics. The distribution of aftershock focal mechanisms corresponds to fault segmentation of the NAFZ in the Izmit-Düzce region produced by coseismic slip. Areas with large amounts of coseismic slip show aftershocks that are predominantly strike-slip, but low-slip barriers show mostly normal faulting aftershocks. Stress tensor inversions of the aftershock focal mechanisms show rotations of the local stresses following the Izmit mainshock. In the Izmit-Sapanca area, the maximum horizontal compressive stress axis is horizontally rotated counter-clockwise by 8° with respect to the coseismic and long-term regional stress field. Towards the eastern end of the rupture (Karadere-Düzce area), stresses are rotated clockwise. We conclude that the Izmit earthquake caused significant stress partitioning along the rupture. The direction of stress rotation is related to the orientation of the individual fault segments along the NAFZ. © 2006 The Authors Journal compilation © 2006 RAS. 2006 English 0956540X 10.1111/j.1365-246X.2006.03027.x Geophysical Journal International 166 373-385 GeoForschungsZentrum Potsdam (GFZ), Telegrafenberg, 14473 Potsdam, Germany 1 aftershock; fault zone; focal mechanism; Kocaeli earthquake 1999; strain analysis; stress analysis, Anatolia; Eurasia; Turkey https://www.scopus.com/inward/record.uri?eid=2-s2.0-33745608736&doi=10.1111%2fj.1365-246X.2006.03027.x&partnerID=40&md5=005771f77ddfa70804488f5c8818bd3c cited By 92 M. Bohnhoff H. Grosser G. Dresen article Xu2006262 Multi-proxy indices on annual/decadal scales during the past 600 years were developed from the surface sediments of Lake Qinghai based on 210Pb and 137Cs geochronology. The δ13Ccarb, δ18Ocarb, and total carbonate content are consistent with one another in trends and their variations have been mainly ascribed to regional temperature. It is suggested that the strong evaporation contributes in modifying δ18O of lake water and δ13C of the dissolved inorganic carbon of the surface water, and appears to be responsible for the covariance between δ13Ccarb and δ18Ocarb. Photosynthesis of the aquatic plants appears to have played a significant role in determining δ15N of organic matter. The discrimination of 14N and 15N during photosynthesis may have triggered a positive linkage between temperatures and δ15Norg (after removal of the stratigraphic trend). Variations of total organic carbon (TOC), C/N ratio, and δ13Corg have been ascribed to local precipitation. TOC (after removal of the stratigraphic trend) is positively correlated with the C/N ratio (r = 0.45, α < 0.01), and negatively correlated with δ13C of organic matter (δ13Corg) (r = - 0.55, α < 0.01); while δ13Corg is negatively correlated with the C/N ratio (r = - 0.48, α < 0.01). The climatic significance of these multi-proxy indices has been verified by comparing with the meteorological records and the climates inferred from tree rings in adjacent regions. © 2006 Elsevier B.V. All rights reserved. Article 2006 English 00092541 10.1016/j.chemgeo.2006.07.005 Chemical Geology 235 262 – 275 3-4 Asia; China; Eurasia; Far East; Qinghai; Qinghai Lake; carbon isotope; carbonate; climate conditions; dissolved inorganic carbon; lacustrine deposit; oxygen isotope; sediment chemistry; stable isotope; total organic carbon https://www.scopus.com/inward/record.uri?eid=2-s2.0-33750606431&doi=10.1016%2fj.chemgeo.2006.07.005&partnerID=40&md5=f7211d128d5f5926b2d0ae53f3072439 Cited by: 136 Hai Xu Li Ai Liangcheng Tan ZhiSheng An article Imanishi200681 We estimate the source parameters of 34 microearthquakes at Parkfield, CA, ranging in size from M -0.2 to M 2.1, by analyzing seismograms recorded by the 32-level, 3-component seismic array installed in the SAFOD Pilot Hole. We succeeded in obtaining stable spectral ratios by stacking the ratios calculated from the moving windows taken along the record following the direct waves. These spectral ratios were modeled to determine seismic moments and corner frequencies assuming an omega-squared model. Static stress drops and apparent stresses of microearthquakes at Parkfield display moment-independent scaling in agreement with scaling laws reported for moderate and large earthquakes. It is likely that the dynamics of microearthquakes at Parkfield is macroscopically similar to that of larger tectonic earthquakes. © 2006 by the American Geophysical Union. 2006 English 9781118666272; 9780875904351 00658448 10.1029/170GM10 Geophysical Monograph Series 170 Blackwell Publishing Ltd McGarr A., Abercrombie R., Di Toro G., Kanamori H. 81-90 Geological Survey of Japan, AIST, Tsukuba, Japan; U. S. Geological Survey, Menlo Park, CA, United States Energy dissipation; Seismic waves; Seismology, Corner frequency; Large earthquakes; Micro-earthquakes; Moment independents; Scaling relationships; Source parameters; Spectral ratios; Tectonic earthquakes, Earthquakes https://www.scopus.com/inward/record.uri?eid=2-s2.0-85040180537&doi=10.1029%2f170GM10&partnerID=40&md5=5426edadeda0660d3b07654862e6920f cited By 69 K. Imanishi W.L. Ellsworth article Ma2006473 Determining the seismic fracture energy during an earthquake and understanding the associated creation and development of a fault zone requires a combination of both seismological and geological field data. The actual thickness of the zone that slips during the rupture of a large earthquake is not known and is a key seismological parameter in understanding energy dissipation, rupture processes and seismic efficiency. The 1999 magnitude-7.7 earthquake in Chi-Chi, Taiwan, produced large slip (8 to 10 metres) at or near the surface, which is accessible to borehole drilling and provides a rare opportunity to sample a fault that had large slip in a recent earthquake. Here we present the retrieved cores from the Taiwan Chelungpu-fault Drilling Project and identify the main slip zone associated with the Chi-Chi earthquake. The surface fracture energy estimated from grain sizes in the gouge zone of the fault sample was directly compared to the seismic fracture energy determined from near-field seismic data. From the comparison, the contribution of gouge surface energy to the earthquake breakdown work is quantified to be 6 per cent. ©2006 Nature Publishing Group. 2006 English 00280836 10.1038/nature05253 Nature 444 Nature Publishing Group 473-476 Department of Earth Sciences, National Central University, Chung-Li 32054, Taiwan; Department of Earth and Planetary Sciences, University of Tokyo, Tokyo 113-0033, Japan; Department of Geosciences, National Taiwan University, Taipei 10617, Taiwan; Disaster Prevention Research Institute, Kyoto University, Kyoto 611-0011, Japan; National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan; Kochi Institute for Core Sample Research, Agency for Marine-Earth Science and Technology, Kochi 783-8502, Japan; Department of Geology and Mineraology, Kyoto University, Kyoto 606-8501, Japan 7118 Drilling platforms; Earthquake effects; Energy dissipation; Interfacial energy; Project management; Surface phenomena, Near field; Rupture processes; Seismic fracture energy; Slip zone, Seismology, borehole; Chi-Chi earthquake 1999; drilling; fault gouge; fault slip; fault zone; grain size; seismometry; surface energy, article; earthquake; energy transfer; geology; particle size; priority journal; surface property; Taiwan; thickness, Asia; Eurasia; Far East; Taiwan https://www.scopus.com/inward/record.uri?eid=2-s2.0-33751328490&doi=10.1038%2fnature05253&partnerID=40&md5=a0b0bce1db6e91139f70e7f43658cd97 cited By 213 K.-F. Ma H. Tanaka S.-R. Song C.-Y. Wang J.-H. Hung Y.-B. Tsai J. Mori Y.-F. Song E.-C. Yeh W. Soh H. Sone L.-W. Kuo H.-Y. Wu article Liu2006569 Laser Raman spectroscopy and cathodoluminescence (CL) images show that zircon from Sulu-Dabie dolomitic marbles is characterized by distinctive domains of inherited (detrital), prograde, ultrahigh-pressure (UHP) and retrograde metamorphic growths. The inherited zircon domains are dark-luminescent in CL images and contain mineral inclusions of Qtz + Cal + Ap. The prograde metamorphic domains are white-luminescent in CL images and preserve a quartz eclogite facies assemblage of Qtz + Dol + Grt + Omp + Phe + Ap, formed at 542-693 °C and 1.8-2.1GPa. In contrast, the UHP metamorphic domains are grey-luminescent in CL images, retain the UHP assemblage of Coe + Grt + Omp + Arg + Mgs + Ap, and record UHP conditions of 739-866 °C and > 5.5 GPa. The outermost retrograde rims have dark-luminescent CL images, and contain low- P minerals such as calcite, related to the regional amphibolite facies retrogression. Laser ablation ICP-MS trace-element data show striking difference between the inherited cores of mostly magmatic origin and zircon domains grown in response to prograde, UHP and retrograde metamorphism. SHRIMP U-Pb dating on these zoned zircon identified four discrete 206Pb/238U age groups: 1823-503 Ma is recorded in the inherited (detrital) zircon derived from various Proterozoic protoliths, the prograde domains record the quartz eclogite facies metamorphism at 254-239 Ma, the UHP growth domains occurred at 238-230 Ma, and the late amphibolite facies retrogressive overprint in the outermost rims was restricted to 218-206 Ma. Thus, Proterozoic continental materials of the Yangtze craton were subducted to 55-60km depth during the Early Triassic and recrystallized at quartz eclogite facies conditions. Then these metamorphic rocks were further subducted to depths of 165-175 km in the Middle Triassic and experienced UHP metamorphism, and finally these UHP metamorphic rocks were exhumed to mid-crustal levels (about 30km) in the Late Triassic and overprinted by regional amphibolite facies metamorphism. The subduction and exhumation rates deduced from the SHRIMP data and metamorphic P-T conditions are 9-10 km Myr-1 and 6.4km Myr-1, respectively, and these rapid subduction-exhumation rates may explain the obtained P-T-t path. Such a fast exhumation suggests that Sulu-Dabie UHP rocks that returned towards crustal depths were driven by buoyant forces, caused as a consequence of slab breakoff at mantle depth. © 2006 Blackwell Publishing Ltd. Article 2006 English 15251314 10.1111/j.1525-1314.2006.00655.x Journal of Metamorphic Geology 24 569 – 589 7 Asia; China; Dabie-Sulu Belt; Eurasia; Far East; cathodoluminescence; dolomite; Raman spectroscopy; retrograde metamorphism; SHRIMP dating; ultrahigh pressure metamorphism; zircon https://www.scopus.com/inward/record.uri?eid=2-s2.0-33747813846&doi=10.1111%2fj.1525-1314.2006.00655.x&partnerID=40&md5=8cb6cdf6b1f8ca3de4c8301159fd08f4 Cited by: 221 Fu Lai Liu A. Gerdes J.G. Liou H.M. Xue F.H. Liang article Liu20061761 Laser Raman spectroscopy and cathodoluminescence (CL) images show that zircons separated from eclogite lens in impure marble from Shuanghe area, Dabie UHP metamorphic belt, are characterized by inherited (detrital), prograde, UHP and retrograde metamorphic overgrowth domains. The inherited (detrital) zircons contain Pl + Ap and Qtz + Pl in the white-luminescent core and the dark-luminescent rim, respectively. Whereas the prograde metamorphic domains (with grey-luminescent CL images) preserve quartz eclogite-facies mineral assemblage of Qtz + Grt + Omp + Phe + Dol + Ap, formed at 588 ∼ 668°C and 1.7 ∼ 1.8CPa. In contrast, the UHP metamorphic domains (with white-luminescent CL images) retain index UHP mineral assemblage of Coe + Grt + Omp + Arg + Mgs + Ap, and record UHP condition of T = 784 ∼ 849°C and P > 5.5GPa. The outmost retrograde rims (with dark-luminescent CL images) however, contain no-UHP minerals such as quartz and calcite, related to the regional amphibolite-facies retrogression with T = 550 ∼ 720°C and P = 0.8 ∼ 1.4GPa. SHRIMP U-Pb dating on these zoned zircons identify four discrete and meaningful age groups: 2701 ∼ 1753Ma (207Pb/206Pb age) is recorded in the inherited (detrital) zircons derived from Archean-Proterozoic protolith, the prograde metamorphism of quartz eclogite-facies in the prograde domains occurred at 249 ∼ 241 Ma (206Pb/238U age), the UHP metamorphic event in the UHP mineral-bearing domains was at 239 ∼ 231Ma (206Pb/238U age), and the late amphibolite-facies retrograde overprint in the outmost rims was restricted at 219 ∼ 211 Ma (206Pb/238U age). Thus, Archean-Proterozoic continental materials of the Dabie UHP terrane were subducted to 55 ∼ 60km depth at Early Triassic and occurred quartz eclogite facies metamorphism simultaneously. Then these quartz eclogite-facies metamorphic rocks continued subduction to 165 ∼ 175km deep mande depth at Middle Triassic and experienced UHP metamorphism; The peak pressures are based on the equilibrium calculation of the reaction dolomite = magnesite + aragonite. This UHP metamorphism recorded a lower geotherm step of 4.7°C km-1 which is within what was previously considered a 'forbidden' condition within earth. Finally these UHP metamorphic rocks were exhumed to mid-crustal levels (about 30km) in the Late Triassic and overprinted regional amphibolite facies metamorphism. The subduction and exhumation rate deduced from the SHRIMP data and metamorphic P-T conditions is 11 ∼ 12km Myr-1 and 7.5 ∼ 8.1km Myr-1, respectively. Fast subduction and rapid exhumation has been considered to be one of the most important factors for the preservation of prograde, UHP and retrograde metamorphic minerals in zircons. Such a fast exhumation suggests that the Dabie UHP metamorphic rocks returned towards the crustal depths as dominant part of a buoyant sliver, caused as a consequence of slab breakoff. Article 2006 Chinese 10000569 Acta Petrologica Sinica 22 Science Press 1761 – 1778 7 Geochronology; Lead; Levees; Luminescence; Marble; Minerals; Quartz; Shellfish; Silicate minerals; Zircon; Dabie UHP terrane; Eclogites; Laser Raman; Mineral inclusions; Shrimp u-pb dating; cathodoluminescence; eclogite; marble; P-T conditions; Raman spectroscopy; retrograde metamorphism; SHRIMP dating; ultrahigh pressure metamorphism; zircon; Metamorphic rocks https://www.scopus.com/inward/record.uri?eid=2-s2.0-84978010012&partnerID=40&md5=1fe64cac7afbe408c6eef9af306c009e Cited by: 33 Fulai Liu Huaimin Xue Zhiqin Xu FengHua Liang Axel Gerdes article Zhang2006378 The Chinese Continental Scientific Drilling (CCSD) main drill hole (0-3000 m) in Donghai, southern Sulu orogen, consists of eclogite, paragneiss, orthogneiss, schist and garnet peridotite. Detailed investigations of Raman, cathodoluminescence, and microprobe analyses show that zircons from most eclogites, gneisses and schists have oscillatory zoned magmatic cores with low-pressure mineral inclusions of Qtz, Pl, Kf and Ap, and a metamorphic rim with relatively uniform luminescence and eclogite-facies mineral inclusions of Grt, Omp, Phn, Coe and Rt. The chemical compositions of the UHP metamorphic mineral inclusions in zircon are similar to those from the matrix of the host rocks. Similar UHP metamorphic P-T conditions of about 770 °C and 32 kbar were estimated from coexisting minerals in zircon and in the matrix. These observations suggest that all investigated lithologies experienced a joint in situ UHP metamorphism during continental deep subduction. In rare cases, magmatic cores of zircon contain coesite and omphacite inclusions and show patchy and irregular luminescence, implying that the cores have been largely altered possibly by fluid-mineral interaction during UHP metamorphism. Abundant H2O-CO2, H2O- or CO2-dominated fluid inclusions with low to medium salinities occur isolated or clustered in the magmatic cores of some zircons, coexisting with low-P mineral inclusions. These fluid inclusions should have been trapped during magmatic crystallization and thus as primary. Only few H2O- and/or CO2-dominated fluid inclusions were found to occur together with UHP mineral inclusions in zircons of metamorphic origin, indicating that UHP metamorphism occurred under relatively dry conditions. The diversity in fluid inclusion populations in UHP rocks from different depths suggests a closed fluid system, without large-scale fluid migration during subduction and exhumation. © 2006 Elsevier B.V. All rights reserved. Article 2006 English 00244937 10.1016/j.lithos.2006.04.003 Lithos 92 378 – 398 3-4 Asia; China; Donghai; Eurasia; Far East; Jiangsu; cathodoluminescence; chemical composition; electron probe analysis; exhumation; fluid inclusion; lithology; magmatic differentiation; mineralization; P-T conditions; Raman spectroscopy; subduction; ultrahigh pressure metamorphism https://www.scopus.com/inward/record.uri?eid=2-s2.0-33748638939&doi=10.1016%2fj.lithos.2006.04.003&partnerID=40&md5=fab03f887a0a7dff9545518d9f3d9507 Cited by: 78 Zeming Zhang Kun Shen Yilin Xiao Jochen Hoefs J.G. Liou article Shervais200656 Article 2006 English 18163459 10.2204/iodp.sd.3.14.2006 Scientific Drilling 1 56 – 57 Geology Department, Utah State University, 4505 Old Main Hill, Logan, UT 84322-4505, United States; Department of Geology, University of Leicester, University Road, Leicester LE1 7RH, United Kingdom; Department of Geological Sciences, University of Idaho, Moscow, ID 83844-3022, United States; Department of Geological Science, San Diego State University, MC-1020, 5500 Campanile Drive, San Diego, CA 92182-1020, United States; Department of Geosciences, Idaho State University, Campus Box 8072, 785 South 8th Avenue, Pocatello, ID 83209-8072, United States; Department of Geological Sciences, University of South Carolina, 701 Sumter Street, Columbia, S.C. 29208, United States 3 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84860848276&doi=10.2204%2fiodp.sd.3.14.2006&partnerID=40&md5=be74630da1f339c16b23d221345767ed Cited by: 12; All Open Access, Gold Open Access, Green Open Access John W. Shervais Michael J. Branney Dennis J. Geist Barry B. Hanan Scott Hughes Alexsander A. Prokopenko Douglas F. Williams article Xiao20064770 The formation of the continental crust (CC) is one of the most important processes in the evolution of the silicate Earth. Exactly how the CC formed is the subject of ongoing debate that focuses on its subchondritic Nb/Ta ratio. Nb and Ta are "geochemical identical twins," so they usually do not fractionate from each other. Here, we show that rutile grains from hydrous rutile-bearing eclogitic layers recovered from drillcores in the Dabie-Sulu ultrahigh pressure terrain have highly variable Nb/Ta values (ranging from 5.4 to 29.1, with an average of 9.8 ± 0.6), indicating major fractionation of Nb and Ta most likely occurred during blueschist to amphibole-eclogite transformation in the absence of rutile. It is suggested that the released fluids with subchondritic Nb/Ta were transported to, and retained by, hydrous rutile-bearing eclogite in colder regions, resulting in suprachondritic Nb/Ta ratios for drier eclogite in hotter regions. Further dehydration of hydrous rutile-bearing eclogites cannot transfer the fractionated Nb/Ta values to the CC due to the low solubility of Nb and Ta in fluids in the presence of rutile, while dehydration-melting results in a major component of the CC, the tonalite-trondhjemite-granodiorite (TTG) component, which is responsible for the low Nb/Ta of the CC. Consequently, residual eclogites have variable but overall suprachondritic Nb/Ta. © 2006 Elsevier Inc. All rights reserved. Article 2006 English 00167037 10.1016/j.gca.2006.07.010 Geochimica et Cosmochimica Acta 70 4770 – 4782 18 continental crust; dehydration melting; eclogite; fractionation; geochemistry; metamorphism; niobium; rutile; slab; tantalum https://www.scopus.com/inward/record.uri?eid=2-s2.0-33749144917&doi=10.1016%2fj.gca.2006.07.010&partnerID=40&md5=147394ef4ec3120790a726b90f78de41 Cited by: 119 Yilin Xiao Weidong Sun Jochen Hoefs Klaus Simon Zeming Zhang Shuguang Li Albrecht W. Hofmann article Gohn200634 2006 English 18168957 10.2204/iodp.sd.3.07.2006 Scientific Drilling 1 34-37 Geological Survey, 926A National Center, Reston, VA, United States; University of Vienna, Vienna, Austria; Rutgers University, Piscataway, NJ, United States; University of the Witwatersrand, Johannesburg, South Africa; Humboldt University, Berlin, Germany 3 https://www.scopus.com/inward/record.uri?eid=2-s2.0-72649104663&doi=10.2204%2fiodp.sd.3.07.2006&partnerID=40&md5=719f0382bcac1fc833556c453b933246 cited By 13 G.S. Gohn C. Koeberl K.G. Miller W.U. Reimold O. Abramov W. Aleman Gonzalez N. Bach A. Blazejak J. Browning T. Bruce C. Budet L. Bybell E. Cobbs Jr. E. Cobbs III C. Cockell B. Corland C. Durand H. Dypvik J. Eckberg L. Edwards S. Eichenauer T. Elbra A. Elmore J. Glidewell G. Gohn A. Gronstal A. Harris P. Heidinger S.-C. Hester W. Horton K. Jones A. Julson D. King J. Kirshtein T. Kohout T. Kraemer D. Kring A. Kulpecz M. Kunk D. Larson U. Limpitlaw M. Lowit N. McKeown P. McLaughlin K. Miller S. Mizintseva R. Morin J. Morrow J. Murray J. Ormö R. Ortiz Martinez L. Petruny H. Pierce J. Plescia D. Powars A. Pusz D.B. Queen D.G. Queen U. Reimold W. Sanford E. Seefelt J. Self-Trail D. Vanko M. Voytek B. Wade J. Wade D. Webster B. Zinn V. Zivkovic article demory2006downcore10 2006 GFZ Data Services François Demory Hedi Oberhänsli N Nowaczyk Matthias Gottschalk R Wirth R Naumann article demory2006downcore1 2006 GFZ Data Services F Demory Hedi Oberhänsli N Nowaczyk Matthias Gottschalk R Wirth R Naumann article demory2006downcore2 2006 GFZ Data Services F Demory Hedi Oberhänsli N Nowaczyk Matthias Gottschalk R Wirth R Naumann article demory2006down 2006 GFZ Data Services François Demory N Nowaczyk Annette Witt Hedi Oberhänsli article Maier2006203 Meteorites provide a sample of Solar System bodies and so constrain the types of objects that have collided with Earth over time. Meteorites analysed to date, however, are unlikely to be representative of the entire population and it is also possible that changes in their nature have occurred with time 1. Large objects are widely believed to be completely melted or vaporized during high-angle impact with the Earth2,3. Consequently, identification of large impactors relies on indirect chemical tracers, notably the platinum-group elements4. Here we report the discovery of a large (25-cm), unaltered, fossil meteorite, and several smaller fragments within the impact melt of the giant (&gt;70 km diameter), 145-Myr-old Morokweng crater, South Africa. The large fragment (clast) resembles an LL6 chondrite breccia, but contains anomalously iron-rich silicates, Fe-Ni sulphides, and no troilite or metal. It has chondritic chromium isotope ratios and identical platinum-group element ratios to the bulk impact melt. These features allow the unambiguous characterization of an impactor at a large crater. Furthermore, the unusual composition of the meteorite suggests that the Morokweng asteroid incorporated part of the LL chondrite parent body not represented by objects at present reaching the Earth. © 2006 Nature Publishing Group. 2006 10.1038/nature04751 Nature 441 203-206 Sciences de la Terre, Université du Québec À Chicoutimi, Chicoutimi, Que. G7H 2B1, Canada; Department of Geology, University of Pretoria, Pretoria 0002, South Africa; South African Nuclear Energy Corporation, Pretoria 0001, South Africa; School of Geosciences, University of the Witwatersrand, Wits 2050, South Africa; School of Earth, Ocean and Planetary Sciences, Cardiff University, Cardiff CF10 3YE, United Kingdom; Scottish Universities Environmental Research Centre, East Kilbride G75 0QF, United Kingdom; Scripps Institution of Oceanography, University of California, San Diego, San Diego, CA 92093, United States; Department of Geological Sciences, Indiana University, Bloomington, IN 47405-7000, United States; Ithemba LABS - Gauteng, Wits 2050, South Africa 7090 https://www.scopus.com/inward/record.uri?eid=2-s2.0-33646550544&doi=10.1038%2fnature04751&partnerID=40&md5=9fe684fb82fdf13a7278b4f59032bdbb cited By 62 W.D. Maier M.A.G. Andreoli I. Mcdonald M.D. Higgins A.J. Boyce A. Shukolyukov G.W. Lugmair L.D. Ashwal P. Gräser E.M. Ripley R.J. Hart article demory2006depth 2006 GFZ Data Services François Demory N Nowaczyk Annette Witt Hedi Oberhänsli article Moran200629 A new deep water drilling system was developed and applied to recover deeply buried sediments for scientific analyses in one of the deep rift valley lakes of Africa - Malawi. This approach overcame the difficulty of maintaining position over a drill site in a remotely located, large, deep lake. Environmental conditions in Lake Malawi are similar to deep water marine settings and, as such, a marine approach was adopted for the Lake Malawi Drilling Project (LMDP). In February and March 2005, the modified pontoon, Viphya, successfully completed a scientific drilling expedition in Lake Malawi. This expedition recovered core at depths greater than 380 m below lake-floor in water depths as great as 600 m. The major refit of Viphya included installation of a moonpool, bridge, crew accommodations, mess, washroom, power system, dynamic positioning, and a drilling system. These major modifications required early pontoon surveys and naval architectural analyses and design work prior to their commencement. The expedition also used modified scientific coring tools with a marine geotechnical drilling rig for the first time, resulting in excellent core recovery and quality. 2006 English 00253324 10.4031/002533206787353637 Marine Technology Society Journal 40 Marine Technology Society Inc. 29-35 University of Rhode Island, United States; Lengkeek Vessel Engineering, Inc.; Seacore Ltd. 1 Dynamic positioning; Environmental engineering; Lakes; Sediments, Geotechnical drilling; Pontoon surveys, Underwater drilling, Dynamic positioning; Environmental engineering; Lakes; Sediments; Underwater drilling, deep drilling; deep sea; drilling rig; environmental conditions, Africa; East African Lakes; Lake Malawi; Sub-Saharan Africa https://www.scopus.com/inward/record.uri?eid=2-s2.0-33845639952&doi=10.4031%2f002533206787353637&partnerID=40&md5=f3d98410e98f3bc79c7c8d3bf395331a cited By 0 K. Moran M. Paulson M. Lengkeek P. Jeffery A. Frazer article WAWRZENITZ2006174 The correlation of deformation fabrics and metamorphic reactions with geochronologic data of UHP metamorphic rocks demonstrate that the multistage subduction and exhumation history of the Central Dabie Complex requires rapid subduction and rapid initial exhumation. Moreover, these data show that volume diffusion is not the major resetting mechanism of radiogenic isotope systems. Thus, our age data do not simply reflect a thermal/cooling history. In the investigated section, the maximum age for UHP is given by the 244±3 Ma (2σ) U–Pb age of a pre-UHP titanite phenocryst that survived UHP metamorphism and subsequent tectonometamorphic events. A minimum age for UHP is set by the 238±1 Ma (2σ) 238U–206Pb mineral isochron age of titanite and cogenetic epidote. These minerals formed from local partial melts during ascent and their age suggests fast exhumation and emplacement in the middle crust. In the period of ca. 238–218 Ma, the UHP terrain records HT metamorphism, local partial melting, and extensive pervasive strain below the eclogite (jd+grt) stability field. Exhumation was polyphase with a first phase of fast exhumation, succeeded by episodes of HT metamorphism and concomitant deformation at deep/mid crustal level between 238 and 218 Ma. Slow exhumation related to the final emplacement of tectonic units along greenschist facies shear zones did not cease before ca. 209–204 Ma. The resetting and homogenization of radiogenic isotope systems were aided by dissolution precipitation creep, which was the dominant deformation mechanism in quartz–feldspar rocks, in combination with fluid influx. 2006 0024-4937 https://doi.org/10.1016/j.lithos.2005.12.001 Lithos 89 174-201 1 UHP metamorphism, Exhumation, Deformation, U–Pb Rb–Sr Sm–Nd isotope dating, Titanite, Dabie Shan https://www.sciencedirect.com/science/article/pii/S0024493705002306 Nicole Wawrzenitz Rolf L. Romer Roland Oberhänsli Shuwen Dong article Stöffler2006519 2006 10.2138/rmg.2006.60.05 Reviews in Mineralogy and Geochemistry 60 519-596 Institut für Mineralogie, Museum für Naturkunde, Humboldt Universität zu Berlin, Invalidenstrasse 43, 10099 Berlin, Germany; Lunar and Planetary Institute, 3600 Bay Area Blvd., Houston, TX 77058, United States; Institute for Dynamics of Geospheres, Leninsky Prospect 38 Bldg. 1, 119334 Moscow, Russian Federation; NASA Johnson Space Center, Houston, TX 77058, United States; Natural Resources Canada, 588 Booth Street, Ottawa, Ont. K1A 0Y7, Canada https://www.scopus.com/inward/record.uri?eid=2-s2.0-33745991997&doi=10.2138%2frmg.2006.60.05&partnerID=40&md5=b035aba5bf6ead8078d7ec7f8e3fff54 cited By 281 D. Stöffler G. Ryder B.A. Ivanov N.A. Artemieva M.J. Cintala R.A.F. Grieve article Arenillas2006241 High-resolution and quantitative planktic foraminiferal biostratigraphy from two SE Mexico stratigraphic sections (Bochil, Guayal) shows that the Chicxulub-related Complex Clastic Unit (CCU) is synchronous with the ejecta-rich airfall layer and the Cretaceous/Paleogene (K/Pg) catastrophic mass extinction horizon in the El Kef (Tunisia) and Caravaca (Spain) sections. The lowermost Danian H. holmdelensis subzone (= Biozone P0) was identified in both sections in a thin dark clay bed just above the CCU, proving that such bed is chronostratigraphically equivalent to the K/Pg boundary clay of the El Kef stratotype. These new micropaleontogical data confirm that the K/Pg impact event and the Chicxulub impact event are the same one. This contradicts the suggestion by others that the Chicxulub impact predated the K/Pg boundary by about 300 ka. © 2006 Elsevier B.V. All rights reserved. 2006 10.1016/j.epsl.2006.07.020 Earth and Planetary Science Letters 249 241-257 Departamento de Ciencias de la Tierra (Paleontología), Universidad de Zaragoza, 50009 Zaragoza, Spain; Instituto Mexicano del Petróleo (Exploración y Producción), Eje Lazaro Cardenas # 152, Mexico D.F. 07730, Mexico; Department of Earth and Planetary Science, University of California, 307 McCone Hall, Berkeley, CA 94720-4767, United States; Petróleos Mexicanos, Exploración y Producción, Blvd. A. Ruiz Cortines 1202, Villahermosa, Tabasco, 86030, Mexico 3-4 https://www.scopus.com/inward/record.uri?eid=2-s2.0-33749334489&doi=10.1016%2fj.epsl.2006.07.020&partnerID=40&md5=b26a3659aa560054bcc5e4f7dad6bb51 cited By 78 I. Arenillas J.A. Arz J.M. Grajales-Nishimura G. Murillo-Muñetón W. Alvarez A. Camargo-Zanoguera E. Molina C. Rosales-Domínguez article Gohn2006349 2006 English 00963941 10.1029/2006EO350001 Eos 87 American Geophysical Union 349-355 USGS, Reston, VA, United States; Department of Geological Sciences, University of Vienna, Vienna, Austria; Department of Geological Sciences, Rutgers University, Piscataway, NJ, United States; Museum of Natural History, Humboldt University, Berlin, Germany; Planetary and Space Sciences Research Institute, Open University, Milton Keynes, United Kingdom 35 buried structure; drilling; impact structure; impactite; meteorite, Chesapeake Bay; North America; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-34247367329&doi=10.1029%2f2006EO350001&partnerID=40&md5=4d398176ab1a88706cb011ed5a8afb23 cited By 51 G.S. Gohn C. Koeberl K.G. Miller W.U. Reimold C.S. Cockell J.W. Horton Jr. W.E. Sanford M.A. Voytek article Gebhardt2006145 Seismic refraction and reflection data were acquired in 2000 and 2003 to study the morphology and sedimentary fill of the remote El'gygytgyn crater (Chukotka, northeastern Siberia; diameter 18 km). These data allow a first insight into the deeper structure of this unique impact crater. Wide-angle data from sonobuoys reveal a five-layer model: a water layer, two lacustrine sedimentary units that fill a bowl-shaped apparent crater morphology consisting of an upper layer of fallback breccia with P-wave velocities of ∼3000 m/s, and a lower layer of brecciated bedrock (velocities >3600 m/s). The lowermost layer shows a distinct anticline structure that, by analogy with other terrestrial and lunar craters of similar size, can be interpreted as a central ring structure. The El'gygytgyn crater exhibits a well-expressed morphology that is typical of craters formed in crystalline target rocks. © 2006 Geological Society of America. 2006 English 00917613 10.1130/G22278.1 Geology 34 145-148 Alfred Wegener Institute for Polar and Marine Research, Columbusstraße, 27568 Bremerhaven, Germany; Alfred Wegener Institute for Polar and Marine Research, Telegrafenberg A43, 14473 Potsdam, Germany 3 Central ring structure; El'gygytgyn; Impact crater; Seismic reflection; Seismic refraction; Anticline structure; Crystalline target rocks; El'gygytgyn; Five layer models; Impact craters; Sedimentary units; Seismic reflections; Seismic refraction, Crystalline rocks; Geologic models; Geomorphology; Lakes; Sedimentology; Seismic waves; Seismology; Crystalline rocks; Lakes; Morphology; Refraction; Sedimentology; Seismic waves, Structural geology; Seismology, impact structure; seismic reflection; seismic refraction; bedrock; breccia; caldera; crater; crater lake; fill; lacustrine deposit; P-wave; preservation; seismic reflection; seismic refraction, Chukchi; Elgygytgyn Lake; Russian Federation https://www.scopus.com/inward/record.uri?eid=2-s2.0-33645227122&doi=10.1130%2fG22278.1&partnerID=40&md5=193525a3a3926841514193d79ce5ceda cited By 38 A.C. Gebhardt F. Niessen C. Kopsch article Scheu2006175 Knowledge of the dynamics of magma fragmentation is necessary for a better understanding of the explosive behaviour of silicic volcanoes. Here we have measured the fragmentation speed and the fragmentation threshold of five dacitic samples (6.7-53.5 vol% open porosity) from Unzen volcano, Kyushu, Japan. The measurements were carried out using a shock-tube-based fragmentation apparatus modified after Alidibirov and Dingwell (1996a,b). The results of the experimental work confirm the dominant influence of porosity on fragmentation dynamics. The velocity of the fragmentation front increases and the value of the fragmentation threshold decreases with increasing porosity. Further, we observe that the fragmentation speed is strongly influenced by the initial pressure difference and the texture of the dacite. At an initial pressure difference of 30 MPa, the fragmentation speed varies from 34 m/s for the least porous sample to 100 m/s for the most porous sample. These results are evaluated by applying them to the 1990-1995 eruptive activity of Unzen volcano. Emplacements of layered lava dome lobes, Merapi-type pyroclastic flows and minor explosive events dominated this eruption. The influence of the fragmentation dynamics on dome collapse and Vulcanian events is discussed. © Springer-Verlag 2006. 2006 English 02588900 10.1007/s00445-006-0066-5 Bulletin of Volcanology 69 175-187 Earth and Environmental Sciences, University of Munich, Theresienstr. 41/III, 80333 Munich, Germany; Earthquake Research Institute, University of Tokyo, 113-0032 Tokyo, Japan 2 explosive volcanism; fragmentation; lava dome; volcanology, Asia; Eurasia; Far East; Japan; Kyushu; Nagasaki [Kyushu]; Unzen Volcano https://www.scopus.com/inward/record.uri?eid=2-s2.0-33747341625&doi=10.1007%2fs00445-006-0066-5&partnerID=40&md5=13bb4a97d81c1abde8e643116bff9669 cited By 51 B. Scheu O. Spieler D.B. Dingwell article Enkelmann2006651 Apatite fission-track thermochronology data elucidate the cooling/ exhumation history of the Qinling (Qin Mountains), which contain a Paleozoic-Mesozoic orogenic collage north of the Sichuan Basin and northeast of the Tibetan Plateau. In particular, we examine the extent to which the Qinling were affected by the rising plateau. The northern and eastern Qinling show continuous cooling and slow exhumation since the Cretaceous. In contrast, in the southwestern Qinling, rapid cooling initiated at 9-4 Ma, a few million years later than in the eastern Tibetan Plateau. A compilation of major Cenozoic faults in the eastern Tibetan Plateau and the Qinling, and their kinematic and dynamic characterization, shows that deformation in the Qinling has predominantly been strike slip. Active sinistral and dextral strike-slip faults delineate an area of eastward rock flow and bound the area of rapid late Cenozoic cooling outlined by apatite fission-track thermochronology. These data can be interpreted to indicate that lower crustal flow has been diverted around the Longmen Shan and beneath the southwestern Qinling, causing active plateau uplift in this area. Alternatively, northeastern Tibet may be growing eastward faster in the western Qinling than the entire South China Block is extruding to the east. © 2006 Geological Society of America. Article 2006 English 00167606 10.1130/B25805.1 Bulletin of the Geological Society of America 118 651 – 671 5-6 Asia; China; Eurasia; Far East; Qinling Mountains; Sichuan Basin; Xizang; Deformation; Dynamics; Geochronology; Kinematics; Seismic prospecting; Structural geology; Cenozoic exhumation; Fission track; Plateau growth; Qinling; Tibet; Cenozoic; deformation; exhumation; fission track dating; lower crust; plateau; structural geology; thermochronology; Geological surveys https://www.scopus.com/inward/record.uri?eid=2-s2.0-33646779177&doi=10.1130%2fB25805.1&partnerID=40&md5=b1b9fe85fd3a5fb7c6c405b4de0fc60c Cited by: 259 Eva Enkelmann Lothar Ratschbacher Raymond Jonckheere Ralf Nestler Manja Fleischer Richard Gloaguen Bradley R. Hacker Yue Qiao Zhang Yin-Sheng Ma article Kashik2006303 This paper presents data on the lithological composition of Cenozoic deposits penetrated for the first time by boreholes BDP-96-1, BDP-96-2, and BDP-98 down to a depth of 600 m on the underwater Akademicheskii Ridge in Lake Baikal. The deposits are subdivided into the upper (Angara) and lower (Barguzin) sequences, which span the Middle Miocene-Holocene period. They formed under different climatic conditions and tectonic settings. Sources of the terrigenous material were also different. Outbursts of diatom-and mineral formation in Lake Baikal can be related to not only climatic fluctuations in the Miocene-Holocene, but also the endogenous activity. By the analogy with the World Ocean, underwater gas-hydrothermal fluid discharge detected at the water-bottom interface in this lake may be accompanied by the formation of diatomaceous oozes and ferromanganese nodule fields and the concentration of rare elements. © Pleiades Publishing, Inc. 2006. Article 2006 English 16083229 10.1134/S0024490206040018 Lithology and Mineral Resources 41 303 – 316 4 https://www.scopus.com/inward/record.uri?eid=2-s2.0-33745966638&doi=10.1134%2fS0024490206040018&partnerID=40&md5=24d78adf8c8a890d6b0e5d3de4dd23c8 Cited by: 4 S.A. Kashik T.K. Lomonosova article Reches200630 2006 English 18168957 10.2204/iodp.sd.3.06.2006 Scientific Drilling 1 30-33 School of Geology and Geophysics, University of Oklahoma, Norman, OK 73019, United States 3 https://www.scopus.com/inward/record.uri?eid=2-s2.0-78650148014&doi=10.2204%2fiodp.sd.3.06.2006&partnerID=40&md5=daa50a530d929846f7ef3d598d109dcb cited By 12 Z. Reches article Cochran2006 Local seismic arrays were deployed at two locations along the San Andreas fault (SAF) near Parkfield, California, before and after the 2004 M 6.0 Parkfield earthquake. Using local earthquakes we determine the anisotropic field within 12 km of the main trace of the SAF at the two array locations separated by 12 km. The initial array, near the SAFOD site, was deployed for six weeks in October and November 2003, and the second array, located near the town of Parkfield, was deployed for 3 months following the 28 September 2004 M 6.0 Parkfield earthquake. We find the fast shear-wave polarization direction nearly fault-parallel (N40°W) for stations on the main fault trace and within 100 m to the southwest of the SAP at both array locations. These fault-parallel measurements span the 100- to 150-m-wide zone of pervasive cracking and damage interpreted from fault-zone-trapped waves associated with the main fault core (Li et al., 2004, 2006). Outside of this zone, the fast orientations are scattered with some preference for orientations near N10°E, roughly parallel to the regional maximum horizontal compressive stress direction (σh). In addition, fast directions are preferentially oriented parallel to a northern branch of the SAF recorded on stations in the 2004 Parkfield deployment. The measured anisotropy is likely due to a combination of stress-aligned microcracks away from the fault and shear fabric within the highly evolved fault core. The majority of our measurements are taken outside of the main fault core, and we estimate the density of microcracks from the measured delay times. Apparent crack densities are approximately 3%, with large scatter. The data suggest weak depth dependence to the measured delay times for source depths between 2 and 7 km. Below 7-km source depth, the delay times do not correlate with depth suggesting higher confining pressure is forcing the microcracks to close. No coseismic variation in the anisotropic parameters is observed, suggesting little to no influence on measured splitting due to the 2004 M 6.0 Parkfield earthquake. However, the premainshock and postmainshock data presented here are from arrays separated by 12 km, limiting our sensitivity to small temporal changes in anisotropy. 2006 English 00371106 10.1785/0120050804 Bulletin of the Seismological Society of America 96 S364-S375 Institute of Geophysics and Planetary Physics, Scripps Institution of Oceanography, University of California at San Diego, San Diego, CA 92093-0225, United States; Earth and Space Sciences Department, Institute of Geophysics and Space Physics, University of California, Los Angeles, CA 90095-1567, United States; Department of Earth Sciences, University of Southern California, Los Angeles, CA 90089-0740, United States 4 B Anisotropic parameters; Postmainshock data; Shallow crust; Shear-wave polarization, Anisotropy; Earthquake effects; Microcracks; Polarization; Shock waves; Compressive stress; Earthquakes; Seismic waves; Shear waves; Tectonics, Earthquakes; Seismology, anisotropy; crust; earthquake event; fault zone; microcrack; Parkfield earthquake 2004; S-wave; San Andreas Fault; trapped wave; coseismic process; earthquake; seismic anisotropy, California; North America; Parkfield; United States, Fast shear-wave polarization; Fault-parallel measurements; Fault-zone-rapped waves; San Andreas fault (SAF); Shallow crust https://www.scopus.com/inward/record.uri?eid=2-s2.0-33845787072&doi=10.1785%2f0120050804&partnerID=40&md5=bcf2e01418fd7f9833cb2fa9cf27c8f0 cited By 68 E.S. Cochran Y.-G. Li J.E. Vidale article Morgan2006264 The precise cause and timing of the Cretaceous-Paleocene (K-P) mass extinction 65 Ma ago remains a matter of debate. Many advocate that the extinction was caused by a meteorite impact at Chicxulub, Mexico, and a number of potential kill-mechanisms have been proposed for this. Although we now have good constraints on the size of this impact and chemistry of the target rocks, estimates of its environmental consequences are hindered by a lack of knowledge about the obliquity of this impact. An oblique impact is likely to have been far more catastrophic than a sub-vertical one, because greater volumes of volatiles would have been released into the atmosphere. The principal purpose of this study was to characterize shocked quartz within distal K-P ejecta, to investigate whether the quartz distribution carried a signature of the direction and angle of impact. Our analyses show that the total number, maximum and average size of shocked quartz grains all decrease gradually with paleodistance from Chicxulub. We do not find particularly high abundances in Pacific sites relative to Atlantic and European sites, as has been previously reported, and the size-distribution around Chicxulub is relatively symmetric. Ejecta samples at any one site display features that are indicative of a wide range of shock pressures, but the mean degree of shock increases with paleodistance. These shock- and size-distributions are both consistent with the K-P layer having been formed by a single impact at Chicxulub. One site in the South Atlantic contains quartz indicating an anomalously high average shock degree, that may be indicative of an oblique impact with an uprange direction to the southeast ± 45°. The apparent continuous coverage of proximal ejecta in this quadrant of the crater, however, suggests a relatively high impact angle of > 45°. We conclude that some of the more extreme predictions of the environmental consequences of a low-angle impact at Chicxulub are probably not applicable. © 2006 Elsevier B.V. All rights reserved. 2006 10.1016/j.epsl.2006.09.009 Earth and Planetary Science Letters 251 264-279 Earth Science and Engineering, Imperial College London, South Kensington Campus, SW7 2AZ London, United Kingdom; Department of Mineralogy, The Nature History Museum, Cromwell Road, SW7 5BD London, United Kingdom; Department of Geology, Royal Holloway University of London, Egham, TW20 0EX, United Kingdom; Osservatorio Geologico di Coldigioco, 62020 Frontale di Apiro, Italy; Geological Survey of Spain (IGME), Calera 1, Tres Cantos, 28760 Madrid, Spain; Departamento de Geologia, Universidade Federal de Pernambuco, 50.740-530 Recife, PEI, Brazil 3-4 https://www.scopus.com/inward/record.uri?eid=2-s2.0-33750496928&doi=10.1016%2fj.epsl.2006.09.009&partnerID=40&md5=c9217c3990a34da1399a481d4e5ad191 cited By 51 J. Morgan C. Lana A. Kearsley B. Coles C. Belcher S. Montanari E. Díaz-Martínez A. Barbosa V. Neumann article Chand2006543 The presence of gas hydrate in marine sediments alters their physical properties. In some circumstances, gas hydrate may cement sediment grains together and dramatically increase the seismic P- and S-wave velocities of the composite medium. Hydrate may also form a load-bearing structure within the sediment microstructure, but with different seismic wave attenuation characteristics, changing the attenuation behaviour of the composite. Here we introduce an inversion algorithm based on effective medium modelling to infer hydrate saturations from velocity and attenuation measurements on hydrate-bearing sediments. The velocity increase is modelled as extra binding developed by gas hydrate that strengthens the sediment microstructure. The attenuation increase is modelled through a difference in fluid flow properties caused by different permeabilities in the sediment and hydrate microstructures. We relate velocity and attenuation increases in hydrate-bearing sediments to their hydrate content, using an effective medium inversion algorithm based on the self-consistent approximation (SCA), differential effective medium (DEM) theory, and Biot and squirt flow mechanisms of fluid flow. The inversion algorithm is able to convert observations in compressional and shear wave velocities and attenuations to hydrate saturation in the sediment pore space. We applied our algorithm to a data set from the Mallik 2L-38 well, Mackenzie delta, Canada, and to data from laboratory measurements on gas-rich and water-saturated sand samples. Predictions using our algorithm match the borehole data and water-saturated laboratory data if the proportion of hydrate contributing to the load-bearing structure increases with hydrate saturation. The predictions match the gas-rich laboratory data if that proportion decreases with hydrate saturation. We attribute this difference to differences in hydrate formation mechanisms between the two environments. © 2006 The Authors Journal compilation © 2006 RAS. 2006 English 0956540X 10.1111/j.1365-246X.2006.03038.x Geophysical Journal International 166 Oxford University Press 543-552 Geological Survey of Norway (NGU), Tromsøkontoret, N-9296 Tromsø, Norway; National Oceanography Centre, European Way, Southampton SO14 3ZH, United Kingdom; School of Civil Engineering and Environment, University of Southampton, Highfield, Southampton SO17 1BJ, United Kingdom; US Geological Survey, 384 Woods Hole Road, Woods Hole, MA 02543, United States 2 algorithm; borehole geophysics; elastic wave; gas hydrate; inverse problem; marine sediment; P-wave; S-wave; wave attenuation https://www.scopus.com/inward/record.uri?eid=2-s2.0-33746134734&doi=10.1111%2fj.1365-246X.2006.03038.x&partnerID=40&md5=eaa4dcfa63d8f19c77a33a2c0b052e20 cited By 54 S. Chand T.A. Minshull J.A. Priest A.I. Best C.R.I. Clayton W.F. Waite article Tuchscherer20061361 Melt particles found at various depths in impactites from the Yaxcopoil-1 borehole into the Chicxulub impact structure (Yucatán) have been analyzed for their major and trace element abundances. A total of 176 electron microprobe and 45 LA-ICP-MS analyses from eight different melt particles were investigated. The main purpose of this work was to constrain the compositions of precursor materials and secondary alteration characteristics of these melt particles. Individual melt particles are highly heterogeneous, which makes compositional categorization extremely difficult. Melt particles from the uppermost part of the impactite sequence are Ca- and Na-depleted and show negative Ce anomalies, which is likely a result of seawater interaction. Various compositional groupings of melt particles are determined with ternary and binary element ratio plots involving major and trace elements. This helps distinguish the degree of alteration versus primary heterogeneity of melt phases. Comparison of the trace element ratios Sc/Zr, Y/Zr, Ba/ Zr, Ba/Rb, and Sr/Rb with compositions of known target rocks provides some constraints on protolith compositions; however, the melt compositions analyzed exceed the known compositional diversity of possible target rocks. Normalized REE patterns are unique for each melt particle, likely reflecting precursor mineral or rock compositions. The various discrimination techniques indicate that the highly variable compositions are the products of melting of individual minerals or of mixtures of several minerals. Small, angular shards that are particularly abundant in units 2 and 3 represent rapidly quenched melts, whereas larger particles (>0.5 mm) that contain microlites and have fluidal, schlieric textures cooled over a protracted period. Angular, shard-like particles with microlites in unit 5 likely crystallized below the glass transition temperature or underwent fragmentation during or after deposition. © The Meteoritical Society, 2006. 2006 10.1111/j.1945-5100.2006.tb00527.x Meteoritics and Planetary Science 41 1361-1379 Impact Cratering Research Group, School of Geosciences, University of the Witwatersrand, Private Bag 3, 2050 Johannesburg, South Africa; Caracle Creek International Consulting Inc., Private Bag X9, Melville 2109, South Africa; Museum für Naturkunde, Humboldt-Universität, Invalidenstrasse 43, D-10115 Berlin, Germany; Council for Geoscience, Private Bag X112, 0001 Pretoria, South Africa; Department of Geological Sciences, University of Cape Town, Rondesbosch 7701, South Africa 9 https://www.scopus.com/inward/record.uri?eid=2-s2.0-33749249955&doi=10.1111%2fj.1945-5100.2006.tb00527.x&partnerID=40&md5=cf65b86b23d5ddfb398aff839098a0d3 cited By 12 M.G. Tuchscherer W.U. Reimold R.L. Gibson D. De Bruin A. Späth article Lozhkin2006 Detailed palynological analysis of glacial, tectonic, and crater lakes of northeastern Siberia reveals continuous records of the changing vegetation during one or several climatic cycles of the Pleistocene and in the Holocene. The most continuous records in the mountain areas of the region are those of Lake Elikchan-4 (northern Okhotsk Sea Region). Pollen records of Lake El-gygytgyn, which was formed by the impact of a meteorite in the northern Chukchi Peninsula, reflect the response of land vegetation to the global climatic impact during the last 300 ka. © Pleiades Publishing, Inc. 2006. 2006 English 00310301 10.1134/S0031030106110098 Paleontological Journal 40 S622-S628 Northeastern Integrated Research Institute, Far East Division, Russian Academy of Sciences, ul. Portovaya 16, Magadan 685000, Russian Federation; Quaternary Research Center, University of Washington, Box 351360, Seattle, WA 98195-1360, United States SUPPL.5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-33749564495&doi=10.1134%2fS0031030106110098&partnerID=40&md5=49069aa40bdddb8dcbd81bebc5737f26 cited By 14 A.V. Lozhkin P.A. Anderson article Boness2006 We present an analysis of shear velocity anisotropy using data in and near the San Andreas Fault Observatory at Depth (SAFOD) to investigate the physical mechanisms controlling velocity anisotropy and the effects of frequency and scale. We analyze data from borehole dipole sonic logs and present the results from a shear-wave-splitting analysis performed on waveforms from microearthquakes recorded on a downhole seismic array. We show how seismic anisotropy is linked either to structures such as sedimentary bedding planes or to the state of stress, depending on the physical properties of the formation. For an arbitrarily oriented wellbore, we model the apparent fast direction that is measured with dipole sonic logs if the shear waves are polarized by arbitrarily dipping transversely isotropic (TI) structural planes (bedding/ fractures). Our results indicate that the contemporary state of stress is the dominant mechanism governing shear velocity anisotropy in both highly fractured granitic rocks and well-bedded arkosic sandstones. In contrast, within the finely laminated shales, anisotropy is a result of the structural alignment of clays along the sedimentary bedding planes. By analyzing shear velocity anisotropy at sonic wavelengths over scales of meters and at seismic frequencies over scales of several kilometers, we show that the polarization of the shear waves and the amount of anisotropy recorded are strongly dependent on the frequency and scale of investigation. The shear anisotropy data provide constraints on the orientation of the maximum horizontal compressive stress SHmax and suggest that, at a distance of only 200 m from the San Andreas fault (SAF), SHmax is at an angle of approximately 70° to the strike of the fault. This observation is consistent with the hypothesis that the SAF is a weak fault slipping at low levels of shear stress. © 2006 Society of Exploration Geophysicists. 2006 English 00168033 10.1190/1.2231107 Geophysics 71 Society of Exploration Geophysicists F131-F146 Stanford University, Stanford, CA 94305, United States; Chevron Energy Technology Company, 6001 Bollinger Canyon Road, San Ramon, CA 94583, United States; Stanford University, Department of Geophysics, Mitchell Building, Stanford, CA 94305, United States 5 Compressive stress; Earthquakes; Granite; Sandstone; Seismic waves; Shale; Shear waves, Seismic array; Seismic frequencies; Shear velocity anisotropy; Shear-wave-splitting analysis; Sonic wavelengths, Seismology, earthquake mechanism; faulting; microearthquake; S-wave; seismic anisotropy; seismic velocity; seismology; waveform analysis https://www.scopus.com/inward/record.uri?eid=2-s2.0-33748850138&doi=10.1190%2f1.2231107&partnerID=40&md5=782aa915abad4d994151296ae14d011a cited By 113 N.L. Boness M.D. Zoback article Rymer2006237 This field trip is along the central section of the San Andreas fault and consists of eight stops that illustrate surface evidence of faulting, in general, and features associated with active fault creep, in particular. Fault creep is slippage along a fault that occurs either in association with small-magnitude earthquakes or without any associated large-magnitude earthquakes. Another aspect of the trip is to highlight where there are multiple fault traces along this section of the San Andreas fault zone in order to gain a better understanding of plateboundary processes. The first stop is along the Calaveras fault, part of the San Andreas fault system, at a location where evidence of active fault creep is abundant and readily accessible. The stops that follow are along the San Andreas fault and at convenient locations to present and discuss rock types juxtaposed across the fault that have been transported tens to hundreds of kilometers by right-lateral motion along the San Andreas fault. Stops 6 and 7 are examples of recent studies of different aspects of the fault: drilling into the fault at the depth of repeating magnitude (M) 2 earthquakes with the San Andreas Fault Observatory at Depth (SAFOD) and the geological, geophysical, and seismological study of M 6 earthquakes near the town of Parkfield. Along with the eight official stops on this field trip are 12 "rolling stops" - sites of geologic interest that add to the understanding of features and processes in the creeping section of the fault. Many of the rolling stops are located where stopping is difficult to dangerous; some of these sites are not appropriate for large vehicles (buses) or groups; some sites are not appropriate for people at all. We include photographs of or from many of these sites to add to the reader's experience without adding too many stops or hazards to the trip. An extensive set of literature is available for those interested in the San Andreas fault or in the creeping section, in particular. For more scientifically oriented overviews of the fault, see Wallace (1990) and Irwin (1990); for a more generalized overview with abundant, colorful illustrations, see Collier (1999). Although the presence of small sections of the San Andreas fault was known before the great 1906 San Francisco earthquake, it was only after that event and subsequent geologic investigations reported in Lawson (1908) that showed the fault as a long structure, extending all the way from east of Los Angeles into northern California. Prentice (1999) described the importance of the 1908 "Lawson report" and how it pivotally influenced the understanding of the San Andreas. Hill (1981) presented a wonderful introduction to the evolution of thought on the San Andreas. Geologic maps and maps of the most recently active fault trace in the creeping section, or large parts of it, include those by Brown (1970), Dibblee (1971, 1980), and Wagner et al. (2002); detailed geologic maps are discussed at various stops in this guide. Various aspects of the creeping section of the San Andreas fault have been the focus of many geologic field trips in the past few decades. Guidebooks for some of those trips include those by Gribi (1963a, 1963b), Brabb et al. (1966), Rogers (1969), Bucknam and Haller (1989), Harden et al. (2001), and Stoffer (2005). The creeping section of the San Andreas fault zone lies between areas that experienced large-displacement surface breakage during great earthquakes in 1857 and 1906 (Fig. 1, inset). Burford and Harsh (1980) divided the creeping section into three segments: (1) a northwest section where the creep rate increases to the southeast in step-like increments, (2) a central section where the creep rate is relatively constant at a maximum value of ∼30 mm/yr (∼1.2 in/yr), and (3) a southeast section where the creep rate decreases to the southeast (Fig. 2). The rate of slip along the creeping section of the fault zone has been measured using creepmeters, alignment arrays, and laser distance-measuring devices. The aperture of measurements over which these measurements are made ranges from 10 m (∼33 ft) (creepmeters) to 100 m (∼330 ft) (alignment arrays) to kilometers and tens of kilometers (laser measuring devices). Creepmeter and alignment-array measurements are here termed "near- fault" measurements; laser measurements over distances of 1-2 km (∼0.6-1.2 mi) are termed "intermediate-scale" measurements; laser measurements over tens of kilometers (miles) are termed "broadscale" measurements. Comparisons among near-fault, intermediate-scale, and broadscale measurements and geologic maps show that the northwest part of the creeping section of the fault is composed of two narrow zones of active deformation, one along the San Andreas fault and one along the Calaveras-Paicines fault, whereas the central and southeast sections are both composed of a single relatively narrow zone of deformation. The southeast section is transitional to a locked zone southeast of Cholame; a locked fault is one that slips only in association with a moderate to large earthquake. Throughout the creeping section of the San Andreas fault zone, broadscale measurements generally indicate more deformation than near-fault and intermediate-scale measurements, which are in reasonably close agreement except at Monarch Peak (Mustang Ridge), near the center of the creeping section and our Stop 5 (Figs. 1 and 2). Features that we see on this trip include offset street curbs, closed depressions (sag ponds), fault scarps (steep slopes formed by movement along a fault), a split and displaced tree, offset fence lines, fresh fractures, and offset road lines (Fig. 3 is a sketch showing some of the landforms that represent deformation by an active fault). We also see evidence of long-term maturity of the San Andreas fault, as indicated by fault features and displaced rock types (Fig. 4). Finally, we will visit sites of ongoing research into the processes associated with earthquakes and their effects. Discussions include drilling into the San Andreas fault at the SAFOD drill site and the 2004 Parkfield earthquake and its effects and implications. © 2006 Geological Society of America. All rights reserved. 2006 English 10.1130/2006.1906SF(16) GSA Field Guides 7 Geological Society of America 237-272 U.S. Geological Survey, 345 Middlefield Road, Menlo Park, CA 94025, United States Creep; Curbs; Earthquakes; Infill drilling; Locks (fasteners); Observatories; Strike-slip faults, Creeping section; Fault structure; Hollister; Parkfield; SAFOD; San Andreas fault, Structural geology https://www.scopus.com/inward/record.uri?eid=2-s2.0-84946417267&doi=10.1130%2f2006.1906SF%2816%29&partnerID=40&md5=85a7796ca33da1b8ff433a7313ab6982 cited By 6 M.J. Rymer S.H. Hickman P.W. Stoffer article Slater2006453 A comparison between the14C content of the methane and dissolved inorganic carbon (DIC) in deep, terrestrial subsurface systems was used to assess the timing of microbial methanogenesis contributing to gases in fracture water samples from three mines in the Witwatersrand Basin, South Africa. The results demonstrated that the majority of methane was produced over geologic timescales. In four of the samples, the methane contained no significant radiocarbon, indicating that the estimated 90% microbial methane in these samples was produced in the geologic past by indigenous microbial communities. In two samples from different mines, methaneΔ14C levels indicated a primarily ancient origin for the microbial methane with the potential for more recent contributions from ongoing indigenous microbial activities constrained to between 0 and40%, and 0 and 24%, respectively. Microbiological evidence for methanogenic archaea was observed in both of these samples. One sample had a Δ14C CH4 that was higher than the corresponding DIC, indicating an extreme decoupling between these species and raising concerns over the representative quality of this sample. The variations in the Δ14C of DIC and CH4 between and within mines demonstrate the need for a thorough assessment of each sample to obtain an accurate understanding of the role and timing of microbiological gas production in these complex, heterogeneous, terrestrial subsurface systems. The approach detailed here introduces timing as a new and widely applicable signature for the recognition of a major geochemical marker of indigenous life in the deep subsurface. © Taylor &amp; Francis. 2006 English 01490451 10.1080/01490450600875787 Geomicrobiology Journal 23 453-462 School of Geography and Earth Sciences, McMaster University, Hamilton, ON, Canada; Lamont-Doherty Earth Observatory, Columbia University, New York, NY, United States; Geo ForschungsZentrum Potsdam, Potsdam, Germany; Division of Earth and Ecosystems Sciences (DEES), Desert Research Institute, Las Vegas, NV, United States; Woods Hole Oceanographic Institution, Woods Hole, MA, United States; Department of Geosciences, Princeton University, Princeton, NJ, United States; Department of Geology, University of Toronto, Toronto, ON, Canada 6 carbon isotope; dissolved inorganic carbon; methane; methanogenesis; microbial activity; microbiology, Africa; South Africa; Southern Africa; Sub-Saharan Africa; Witwatersrand, Archaea https://www.scopus.com/inward/record.uri?eid=2-s2.0-85023830705&doi=10.1080%2f01490450600875787&partnerID=40&md5=692d4fc6e51a1b47cf6087f57994d7fd cited By 4 G.F. Slater J. Lippmann-Pipke D.P. Moser C.M. Reddy T.C. Onstott G. Lacrampe-Couloume B. Lollar article Nakada200637 To understand the structure and growth history of Unzen Volcano in Japan and to clarify the eruption mechanisms of SiO 2-rich viscous magmas, the Unzen Scientific Drilling Project (USDP), a six-year program consisting of two phases, began in April 1999. In the first phase, two holes were drilled into the volcano's flank (USDP-1 and -2 wells). In the second phase, drilling penetrated the magma conduit that fed a lava dome at the summit during the 1991-95 eruption. Through directional drilling, samples of the lava dike believed to have fed the 1991-95 eruption were recovered. The lava dike sample was unexpectedly altered, suggesting that circulation of hydrothermal fluids rapidly cools the conduit region of even very active volcanoes. It is likely that seismic signals monitored before the emergence of lava dome reflected fracturing of the country rocks, caused by veining as volatiles escaped predominantly upward, not outward, from the rising magma. 2006 English 09693769 Geodrilling International 37-39 Earthquake Research Institute, University of Tokyo, Tokyo, Japan; Geological Survey of Japan, Japan; Japan Metals and Chemicals Co., Japan; Geophysical Institute, University of Alaska, Fairbanks, AK, United States; Institute of Seismology and Volcanology, Kyushu University, Higashi-ku, Fukuoka, Japan 120 drilling https://www.scopus.com/inward/record.uri?eid=2-s2.0-33645349337&partnerID=40&md5=b496f9f7581e2ef1fe66dd7ed94e0461 cited By 0 S. Nakada K. Uto S. Sakuma J. Eichelberger H. Shimizu article Riedel2006 Amplitude and frequency anomalies associated with lakes and drainage systems were observed in a 3D seismic data set acquired in the Mallik area, Mackenzie Delta, Northwest Territories, Canada. The site is characterized by large gas hydrate deposits inferred from well-log analyses and coring. Regional interpretation of the gas hydrate occurrences is mainly based on seismic amplitude anomalies, such as brightening or blanking of seismic energy. Thus, the scope of this research is to understand the nature of the amplitude behavior in the seismic data. We have therefore analyzed the 3D seismic data to define areas with amplitude reduction due to contamination from lakes and channels and to distinguish them from areas where amplitude blanking may be a geologic signal. We have used the spectral ratio method to define attenuation (Q) over different areas in the 3D volume and subsequently applied Q-compensation to attenuate lateral variations ofdispersive absorption. Underneath larger lakes, seismic amplitude is reduced and the frequency content is reduced to 20-40 Hz, which is half the original bandwidth. Traces with source-receiver pairs located inside of lakes show an attenuation factor Q of ∼ 40, approximately half of that obtained for source-receiver pairs situated on deep, continuous permafrost outside of lakes. Deeper reflections occasionally identified underneath lakes show low-velocity-related pull-down. The vertical extent of the washout zones is enhanced by acquisition with limited offsets and from processing parameters such as harsh mute functions to reduce noise from surface waves. The strong attenuation and seismic pull-down may indicate the presence of unfrozen water in deeper lakes and unfrozen pore water within the sediments underlying the lakes. Thus, the blanking underneath lakes is not necessarily related to gas migration or other in situ changes in physical properties potentially associated with the presence of gas hydrate. © 2006 Society of Exploration Geophysicists. 2006 English 00168033 10.1190/1.2338332 Geophysics 71 Society of Exploration Geophysicists B183-B191 Natural Resources Canada, Geological Survey of Canada - Sidney Pacific Geoscience Center, 9860 West Saanich Road, Sidney, BC V8L 4B2, Canada; Natural Resources Canada, Geological Survey of Canada - Ottawa, 615 Booth Street, Ottawa, ON K1A 0E9, Canada 6 Drainage; Lakes; Permafrost; Seismic waves; Spectrum analysis; Surface waves; Well logging, Gas hydrate deposits; Seismic amplitude; Seismic data, Seismology, amplitude; data interpretation; seismic attenuation; seismic data; seismic migration; seismology; spectral analysis; surface wave; three-dimensional modeling; well logging, Canada; Mackenzie Delta; North America; Northwest Territories https://www.scopus.com/inward/record.uri?eid=2-s2.0-33751070379&doi=10.1190%2f1.2338332&partnerID=40&md5=43b4df8bfd7f327a71cd2101208d0373 cited By 21 M. Riedel G. Bellefleur S.R. Dallimore A. Taylor J.F. Wright article Wang2006 On 20 September 1999, the Ms7.6 Chi-Chi earthquake raptured the Chelungpu fault in central Taiwan. Integrating observed and inversed results of source parameters, the fracture energy, Eg. and frictional energy, Ef, on the fault and its northern and southern segments are estimated. Together with given values of strain energy, ΔE, and seismic radiation energy, Es, the seismic efficiency, i.e., η = Es/ΔE, and the radiation efficiency, i.e., ηR = Es/(Es + Eg), are evaluated. The average fracture energy per unit area, G, is also calculated from Eg. The frictional heat caused by dynamic frictional stress is calculated from Ef. Results show a marked difference in source properties between the two segments. The average frictional and ambient stress levels on the two segments are estimated. The total energy budget of and heat generated by the earthquake are elucidated based on a two-dimensional faulting model with frictional heat. Both observed and calculated results suggest the possible existence of fluids, which produced suprahydrostatic gradients, on the fault during faulting. Lubrication and thermal fluid pressurization might play a significant role on rupture. Copyright 2006 by the American Geophysical Union. 2006 English 21699313 10.1029/2005JB004018 Journal of Geophysical Research: Solid Earth 111 Blackwell Publishing Ltd Institute of Earth Sciences, Academia Sinica, P.O. Box 1-55, Nangang, Taipei 115, Taiwan 11 Chi-Chi earthquake 1999; earthquake magnitude; earthquake rupture; energy budget; faulting; seismicity; source parameters, Asia; Eurasia; Far East; Taiwan https://www.scopus.com/inward/record.uri?eid=2-s2.0-34547557596&doi=10.1029%2f2005JB004018&partnerID=40&md5=164ac9aa6323226cbba73ac139970127 cited By 24 J.-H. Wang article demory2006hysteresis 2006 GFZ Data Services François Demory Hedi Oberhänsli N Nowaczyk Matthias Gottschalk R Wirth R Naumann article Deutsch2006689 The Chesapeake Bay impact structure, which is about 35 Ma old, has previously been proposed as the possible source crater of the North American tektites (NAT). Here we report major and trace element data as well as the first Sr-Nd isotope data for drill core and outcrop samples of target lithologies, crater fill breccias, and post-impact sediments of the Chesapeake Bay impact structure. The unconsolidated sediments, Cretaceous to middle Eocene in age, have εSrt=35.7Ma of +54 to +272, and εNdt=35.7Ma ranging from -6.5 to - 10.8; one sample from the granitic basement with a TNdCHUR model age of 1.36 Ga yielded an εSrt=35.7Ma of + 188 and an εNdt=35.7Ma of -5.7. The Exmore breccia (crater fill) can be explained as a mix of the measured target sediments and the granite, plus an as-yet undetermined component. The post-impact sediments of the Chickahominy formation have slightly higher TNdCHUR model ages of about 1.55 Ga, indicating a contribution of some older materials. Newly analyzed bediasites have the following isotope parameters: +104 to +119 (εSrt=35.7Ma), -5.7 (εNdt=35.7Ma), 0.47 Ga (TSsUR), and 1.15 Ga (TNdCHUR), which is in excellent agreement with previously published data for samples of the NAT strewn field. Target rocks with highly radiogenic Sr isotopic comparison, as required for explaining to isotopic characteristic of Deep Sea Drilling Project (DSDP) site 612 tektites, were not among the analyzed sample suite, Based on the new isotope data, we exclude any relation between the NA tektites and the Popigai impact crater, athough they have identical ages within 2σ errors. The Chesapeake Bay structure, however, is now clearly constrained as the source crater for the North American tektites, although the present data set obviously does not include all target lithologies that have contributed to the composition of the tektites. © The Meteoritical Society, 2006. 2006 English 10869379 10.1111/j.1945-5100.2006.tb00985.x Meteoritics and Planetary Science 41 University of Arkansas 689-703 Institut für Planetologie (IfP), Westfälische Wilhelms-Universität Münster (WWU), Wilhelm-Klemm-Str. 10, D-48149 Münster, Germany; Zentrallabor für Geochronologie (ZLG), WWU, Corrensstr. 24, D-48149 Münster, Germany; Department of Geological Sciences, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria 5 crater; Deep Sea Drilling Project; impact structure; isotopic composition; neodymium; strontium; tektite https://www.scopus.com/inward/record.uri?eid=2-s2.0-33744489305&doi=10.1111%2fj.1945-5100.2006.tb00985.x&partnerID=40&md5=09869c079c1b8c29978950a8421aa6d7 cited By 44 A. Deutsch C. Koeberl article Rebolledo-Vieyra20061309 We report on the magnetostratigraphy of the Chicxulub crater impact breccias and first 15 meters of the Paleocene sedimentary sequence recovered in three boreholes of the UNAM Scientific Drilling Program. Three geomagnetic polarity zones are documented in the impact breccias and sedimentary sequence, which span from chron 29R to 28N. For the 15 m interval they represent~2.5 Ma, which yields low apparent sedimentary rates for boreholes UNAM-5 (110 km from the center of the crater) and UNAM-7 (127 km from the center of the crater). The carbonate sedimentary sequence can be associated to a shallow basin depositional environment. In these boreholes the thickness between the 29R and the 29N chrons is just 0.5 m, suggesting that during the 100 ka from the K/T boundary to the polarity transition sediments were not deposited or eroded. Within borehole UNAM-6 (152 km from the center of the crater) it appears that sediments containing chron 29N are missing, the lack of the upper breccias, the long duration of a reversal event within the base of the sequence and low apparent sedimentary rate of 3.3 m/Ma, suggests a hiatus within the impact breccias and the basal Paleocene sedimentary sequence. Magnetic susceptibility logs confirm absence of the upper breccias at UNAM-6 borehole. Magnetic susceptibility values increase towards the base of the sequence, suggesting that basement and melt clasts were subjected to a low temperature hydrothermal alteration. © 2006, The Seismological Society of Japan, Society of Geomagnetism and Earth, Planetary and Space Sciences, The Volcanological Society of Japan, The Geodetic Society of Japan, The Japanese Society for Planetary Sciences. All rights reserved. 2006 10.1186/BF03352626 earth, planets and space 58 1309-1314 Laboratorio de Paleomagnetismo, Instituto de Geofisica, UNAM, Circuito Exterior SIN, Coyoacan, Mexico 10 https://www.scopus.com/inward/record.uri?eid=2-s2.0-33846072659&doi=10.1186%2fBF03352626&partnerID=40&md5=61a56c41e1903c93fb34d47e0225a9db cited By 15 M. Rebolledo-Vieyra J. Urrutia-Fucugauchi article Browne2006103 Textural and geochemical characteristics of plagioclase phenocrysts from the eruptive products of Mount Unzen (SW Japan) record repeated intrusions of basaltic magma into a dacitic host magma chamber over the lifetime of the volcano. An important aspect of this mixing style is the exchange of phenocrysts between the intruding basalt magma and host dacite magma, and the effect that this wide-reaching mixing style has on the mineralogical diversity of the erupted products. Plagioclase phenocrysts that originally crystallized from the host dacite magma are identified by oscillatory zoning patterns, low An content cores (An45 to An60), and low Sr / Ba ratios. Host-derived plagioclase phenocrysts are engulfed during intrusion of basaltic magma, evidenced by their presence in basaltic to andesitic enclaves. In response to changes in temperature and composition of the surrounding melt, the engulfed plagioclases develop resorption zones, which are composed of a densely packed network of micron-sized glass inclusions and high An content plagioclase (An72-An92) with high Sr / Ba ratios that match those of plagioclase microphenocrysts inherent to the enclave-forming magma. Over time, host-derived plagioclase phenocrysts that were once engulfed during replenishment events are recycled back to the host as enclaves disaggregate (e.g.[ Clynne, M.A., 1989. The disaggregation of quenched magmatic inclusions contributes to chemical diversity in silicic lavas of Lassen Peak, California. Bull New Mexico Bureau of Mines and Mineral Resources, 131: 54]). An eruption of andesite lava with no enclaves, something particularly unique for Unzen, occurred in 1663. Similar to enclaves, all plagioclase phenocrysts in this lava flow are surrounded by resorption zones suggesting that the 1663 lava may represent a magma that was erupted after thoroughly mixing with the intruding basaltic. Using experimentally calibrated crystallization rates, we estimate that phenocrysts exist in the Unzen chamber a minimum of 0.5-3 months between the time of their encounter with a basaltic intrusion and eruption. © 2006 Elsevier B.V. All rights reserved. 2006 English 03770273 10.1016/j.jvolgeores.2005.09.022 Journal of Volcanology and Geothermal Research 154 103-116 University of Alaska Fairbanks Geophysical Institute, Fairbanks, AK 99775, United States; Michigan State University, Department of Geological Sciences, East Lansing, MI 48824, United States; Geological Survey of Japan, Higashi 1-1-3, Tsukuba, 305-8567, Japan 1-2 Crystallization; Geochemistry; Laser ablation; Mineralogy; Trace elements, Enclaves; Magma mixing; Plagioclase; Unzen volcano, Volcanoes, andesite; lava flow; magma; phenocryst; plagioclase; volcanic eruption, Asia; Eurasia; Far East; Japan; Kyushu; Nagasaki [Kyushu]; Unzen Volcano https://www.scopus.com/inward/record.uri?eid=2-s2.0-33646866594&doi=10.1016%2fj.jvolgeores.2005.09.022&partnerID=40&md5=4bb74c469245b9eb1704d4599b5f7811 cited By 92 B.L. Browne J.C. Eichelberger L.C. Patino T.A. Vogel K. Uto H. Hoshizumi article Zanoth20062304 This paper is concerned with the leaky mode, a possible horizontal attenuation phenomenon of seismic waves in a gas hydrate-bearing sediment layer. This attenuation mechanism in horizontal direction occurs when a high-velocity layer is embedded in a low-velocity zone. This is a typical situation for gas hydrate occurrences. To quantify th is mechanism a digital rock model based on the crosswell-data of the Mallik 2002 Gas Hydrate Research Well Program is created. In our elastic simulations we can exclude attenuation mechanism like scattering loss or intrinsic absorption. We will demonstrate that the leaky mode is a significant horizontal attenuation mechanism which cannot be neglected. © 2005 Society of Exploration Geophysicists. 2006 English 9781604236972 10523812 10.1190/1.2369996 SEG Technical Program Expanded Abstracts 25 Society of Exploration Geophysicists 2304-2308 Fachbereich Geophysik, Freie Universität Berlin, Berlin, Germany 1 Geophysical prospecting; Hydration; Petroleum prospecting; Seismology, Gas hydrate bearing sediments; High velocity; Horizontal attenuation; Intrinsic absorptions; Leaky modes; Low velocity zones; Scattering loss; Seismic attenuation, Gas hydrates https://www.scopus.com/inward/record.uri?eid=2-s2.0-33845406929&doi=10.1190%2f1.2369996&partnerID=40&md5=4135db4bf5b6f117627b3a6e350d3539 cited By 0 S.R. Zanoth E.H. Saenger O.S. Krüger S.A. Shapiro article Anselmetti200652 We used seismic images and sedimentary data from piston cores to conduct a sequence stratigraphic analysis of sediments in Lake Petén Itzá, northern Guatemala. Our results document lake level fluctuations in this lowland Neotropical region that were related to glacial-to-interglacial climate change during the Late Pleistocene. A bathymetric survey of Lake Petén Itzá (area = 100 km2) revealed a maximum water depth of ∼160 m and the existence of a deep cryptodepression that extends 50 m below modern sea level. The great depth suggests that the basin held water even during arid conditions associated with full glacial periods. Lake Petén Itzá may thus possess the only long continuous lacustrine sediment record of Late Pleistocene environmental and climate change in the lowland Neotropics. Two seismic reflection campaigns imaged the subsurface basin sediments that overlie basement. The sediment package was divided into four major seismic sequences (T, G, R, and B). Sequences are separated by unconformities that represent depositional cycles related to lake level fluctuations. Sediments of the uppermost sequence (T) were recovered and radiocarbon-dated in Kullenberg piston cores taken along a water depth transect. Seismic profiles reveal a basin-wide paleoshoreline just below sequence T at ∼56 m below present lake level. This constructional feature formed during a lowstand of the last glacial period when the lake was reduced to only ∼13% of its present volume. In cores taken landward of the paleoshoreline, Late Glacial-age deposits consist of paleosols, indicating subaerial exposure. Basinward of the shoreline, sediments are composed of dense gypsum sands and interbedded silty clays, reflecting authigenic gypsum formation under arid climate conditions. The top of the soil horizon and cessation of gypsum precipitation are represented by a strong seismic reflection (t). It marks the base of the uppermost seismic sequence T and is dated in several cores between ∼11.1 and 10.2 cal kyr BP. Lake level rose quickly at this time in response to a shift from arid-to-humid climate conditions at the Late Glacial/Early Holocene transition. We infer a similar sediment response to climate variations in the older stratigraphic sequences (G, R, and B), related to earlier glacial-to-interglacial and stadial-to- interstadial cycles. Older sequences are also distinguished from one another by erosional unconformities that probably represent major lake level falls. Future recovery of the older stratigraphic record by drilling in Lake Petén Itzá will provide ages for these older units and enable us to test the depositional model inferred from seismic stratigraphy. © 2005 Elsevier B.V. All rights reserved. Article 2006 English 00310182 10.1016/j.palaeo.2005.06.037 Palaeogeography, Palaeoclimatology, Palaeoecology 230 52 – 69 1-2 Central America; Guatemala [Central America]; climate variation; lacustrine deposit; paleoclimate; Quaternary; seismic stratigraphy https://www.scopus.com/inward/record.uri?eid=2-s2.0-29744467735&doi=10.1016%2fj.palaeo.2005.06.037&partnerID=40&md5=a9b299ba54b9d245bc7442693db63f78 Cited by: 71 F.S. Anselmetti D. Ariztegui D.A. Hodell M.B. Hillesheim M. Brenner A. Gilli J.A. McKenzie A.D. Mueller article zhisheng2006lake 2006 https://doi.org/10.2204/iodp.sd.2.05.2006 Scientific Drilling 2 ICDP-IODP Göttingen, Germany 20-22 An Zhisheng Ai Li Song Yougui Steven M Colman article Zolitschka200654 Note 2006 10.2204/iodp.sd.3.13.2006 Scientific Drilling 1 54 – 55 3 https://www.scopus.com/inward/record.uri?eid=2-s2.0-77952669088&doi=10.2204%2fiodp.sd.3.13.2006&partnerID=40&md5=14943bbe7f8bcb6fe21165e20eb6bf26 Cited by: 3; All Open Access, Gold Open Access, Green Open Access Bernd Zolitschka Hugo Corbella Nora Maidana Christian Ohlendorf article demory2006intercorrelation 2006 GFZ Data Services F Demory N Nowaczyk A Witt Hedi Oberhänsli article demory2006inclination 2006 GFZ Data Services François Demory N Nowaczyk Annette Witt Hedi Oberhänsli article Doan2006 [1] Hydraulic diffusivity controls fluid pressure and hence affects effective normal stress during rupture. Models suggest a particularly spectacular example of fluid pressurization during the Mw = 7.6 1999 Chichi earthquake when pressurization may have reduced high-frequency shaking in the regions of large slip if the fault was sufficiently sealed. We investigate in situ hydraulic diffusivity which is the key parameter in such models through a cross-hole experiment. We find a diffusivity of D = (7 ±1) × 10-5 m2/s, which is a low value compatible with pressurization of the Chelungpu fault during the earthquake. In most poroelastic media, the hydraulic storativity 5 lies between 10-7 and 10 -5, so that the transmissivity T along the fault zone is comprised between 10-11 m2/s and 10-9 m2/s. The corresponding permeability (10-18-10-16 m2) is at most one hundred times larger than the value obtained on core samples from the host rock. The fault zone is overpressurized by 0.06 to 6 MPa, which is between 0.2% and 20% of the lithostatic pressure. Copyright 2006 by the American Geophysical Union. 2006 English 00948276 10.1029/2006GL026889 Geophysical Research Letters 33 American Geophysical Union Earth Science Department, University of Santa Cruz, Santa Cruz, CA, United States; National Central University, Chung-li, Taiwan; Disaster Prevention Research Institute, Kyoto University, Kyoto, Japan; Earth Science Department, Earth and Marine Sciences Building, University of Santa Cruz, 1156 High Street, Santa Cruz, CA 95064, United States; Disaster Prevention Research Institute, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan; National Central Universijy, Chung-li 320-54, Taiwan 16 Carrier communication; Core samples; Diffusion; Earthquakes; Fluid dynamics; Mathematical models; Pressure effects; Stress analysis, Fault zone; Hydraulic diffusivity; Lithostatic pressure; Poroelastic media, Hydraulic fracturing, crosshole seismic method; diffusion; earthquake; fault; fluid pressure; hydraulic conductivity; poroelasticity, Asia; Eurasia; Far East; Taiwan https://www.scopus.com/inward/record.uri?eid=2-s2.0-33845662656&doi=10.1029%2f2006GL026889&partnerID=40&md5=a115401e85bbca02e2fc6e568abb80f5 cited By 66 M.L. Doan E.E. Brodsky Y. Kano K.F. Ma article melezhik2006icdp 2006 Scientific Drilling 2 56--57 Victor A Melezhik Aivo Lepland article Lin2006479 Geochemical, microbiological, and molecular analyses of alkaline saline groundwater at 2.8 kilometers depth in Archaean metabasalt revealed a microbial biome dominated by. a single phylotype affiliated with thermophilic sulfate reducers belonging to Firmicutes. These sulfate reducers were sustained by geologically produced sulfate and hydrogen at concentrations sufficient to maintain activities for millions of years with no apparent reliance on photosynthetically derived substrates. 2006 English 00368075 10.1126/science.1127376 Science 314 479-482 Department of Geosciences, Princeton University, Princeton, NJ, United States; Department of Geosciences, National Taiwan University, Taipei, Taiwan; Institute of Oceanography, National Taiwan University, Taipei, Taiwan; Geophysical Laboratory, Carnegie Institution of Washington, Washington, DC, United States; GeoForschungsZentrum Potsdam, Telegrafenberg, Potsdam, Germany; Department of Geological Sciences, Indiana University, Bloomington, IN, United States; Department of Geology, University of Toronto, Toronto, Ont., Canada; Ecology Department, Lawrence Berkeley National Laboratory, Berkeley, CA, United States; Division of Earth and Ecosystems Sciences, Desert Research Institute, Las Vegas, NV, United States; Mponeng Mine, Anglo Gold, Johannesburg, South Africa 5798 Basalt; Geochemistry; Groundwater; Photosynthesis; Reduction; Salts, Metabasalt; Microbial biomes, Microbiology, ground water; hydrogen; sulfate, Archean; biome; groundwater; high energy environment; hydrogen; metabasalt; molecular analysis; salinity; sulfate; sulfate-reducing bacterium, Archean; article; biome; environmental sustainability; Firmicutes; geochemical analysis; microbiology; photosynthesis; priority journal, Bacteria; Biodiversity; DNA, Ribosomal; Ecosystem; Gold; Hydrogen; Mining; Oligonucleotide Array Sequence Analysis; Oxidation-Reduction; Phylogeny; RNA, Ribosomal, 16S; South Africa; Sulfates; Temperature; Thermodynamics; Time; Water Microbiology, Firmicutes https://www.scopus.com/inward/record.uri?eid=2-s2.0-33750332574&doi=10.1126%2fscience.1127376&partnerID=40&md5=9720d92d3f344f7da8d40873c90885ea cited By 287 L.-H. Lin P.-L. Wang D. Rumble J. Lippmann-Pipke E. Boice L.M. Pratt B.S. Lollar E.L. Brodie T.C. Hazen G.L. Andersen T.Z. DeSantis D.P. Moser D. Kershaw T.C. Onstott conference Dallimore20061456 Gas hydrates are solid crystalline substances consisting of natural gas (typically methane) and water molecules, that remain stable under conditions of relatively cold formation temperatures and high pressures. Significant natural gas hydrates deposits occur in the Arctic in association with areas of thick permafrost, and in many marine environments around the world. Their energy potential is significant as the in place estimates of gas hydrate are thought to significantly exceed conventional natural gas resource estimates. While gas hydrates could represent a vast unconventional, environmentally-friendly natural gas resource, the challenges to realise their energy potential remain significant. They occur in remote frontier settings, new exploration methods are required to locate concentrated deposits, and technologies to produce them have not proven. Success will likely require a combination of science, technology and favourable economics. Interest in gas hydrates as an energy resource has grown in recent years with many countries having established national research and development programs. Scientific and exploratory drilling has taken place in Japan, Canada and the USA, and field programs are also planned in the near future offshore of India and China. In 2002, a seven member research partnership conducted small-scale production testing at the Mallik site in Canada's Northwest Territories. Two 1188 m science observation wells and a 1166 m production research well were drilled and instrumented to examine gas production and the physical behaviour of reservoir sediments in response to depressurization and thermal stimulation. Other aspects of the program included the collection of gas hydrate core samples, downhole geophysical logging and extensive laboratory and modeling studies. The results of the production testing and scientific investigations have been released Geological Survey of Canada Bulletin that includes 62 scientific papers and an extensive data base. Copyright 2006, European Association of Geoscientists and Engineers. 2006 English 10.3997/2214-4609.201402215 Society of Petroleum Engineers, 68th European Association of Geoscientists and Engineers Conference and Exhibition, incorporating SPE EUROPEC 2006, EAGE 2006: Opportunities in Mature Areas 3 Society of Petroleum Engineers 1456 Canadian Geol Survey, Canada Crystalline materials; Database systems; Energy resources; Permafrost; Pressurization; Risk assessment, Cold formation temperatures; Downhole geophysical logging; Natural gas hydrates; Natural gas resources, Gas hydrates https://www.scopus.com/inward/record.uri?eid=2-s2.0-33947252704&doi=10.3997%2f2214-4609.201402215&partnerID=40&md5=4b557cb15dbf0ae2108df13f91e03f3b cited By 0 S. Dallimore article Browne2006301 Mafic to intermediate enclaves are evenly distributed throughout the dacitic 1991-1995 lava sequence of Unzen volcano, Japan, representing hundreds of mafic recharge events over the life of the volcano. This study documents the morphological, textural, chemical, and petrological characteristics of the enclaves and coexisting silicic host lavas. The eruptive products described in this study appear to be general products of magma mingling, as the same textural types are seen at many other volcanoes. Two types of magmatic enclaves, referred to as Porphyritic and Equigranular, are easily distinguished texturally. Porphyritic enclaves display a wide range in composition from basalt to andesite, are glass-rich, spherical and porphyritic, and contain large, resorbed, plagioclase phenocrysts in a matrix of acicular crystals and glass. Equigranular enclaves are andesitic, non-porphyritic, and consist of tabular, medium-grained microphenocrysts in a matrix glass that is in equilibrium with the host dacite magma. Porphyritic enclaves are produced when intruding basaltic magma engulfs melt and phenocrysts of resident silicic magma at their mutual interface. Equigranular enclaves are a product of a more prolonged mixing and gradual crystallization at a slower cooling rate within the interior of the mafic intrusion. © The Author 2005. Published by Oxford University Press. All rights reserved. 2006 English 00223530 10.1093/petrology/egi076 Journal of Petrology 47 301-328 University of Alaska Fairbanks, Geophysical Institute, Fairbanks, AK 99775, United States; Michigan State University, Department of Geological Sciences, East Lansing, MI 48824, United States; Geological Survey of Japan, Higashi 1-1-3, Tsukuba, Ibaraki 305-8567, Japan; California State University, Department of Geological Sciences, Fullerton, CA 92834, United States 2 enclave; mafic rock; magmatism; petrogenesis, Asia; Eurasia; Far East; Japan; Kyushu; Nagasaki [Kyushu]; Unzen Volcano https://www.scopus.com/inward/record.uri?eid=2-s2.0-31544433943&doi=10.1093%2fpetrology%2fegi076&partnerID=40&md5=cbcec4529d6996b61df9f7ae1a8db2a3 cited By 73 B.L. Browne J.C. Eichelberger L.C. Patino T.A. Vogel J. Dehn K. Uto H. Hoshizumi article demory2006hirm 2006 GFZ Data Services François Demory Hedi Oberhänsli N Nowaczyk A Witt article Micarelli200631 This paper reviews the data concerning the fracture network and the hydraulic characteristics of faults in an active zone of the Gulf of Corinth. Pressure gap measured through fault planes shows that in this area the active normal faults (Aigion, Helike) act, at least temporarily and locally, as transversal seal. The analysis of the carbonate cements in the fractures on both the hangingwall and the footwall of the faults also suggests that they have acted as local seals during the whole fault zone evolution. However, the pressure and the characteristics of the water samples measured in the wells indicate that meteoric water circulates from the highest part of the relief to the coast, which means it goes through the fault zones. Field quantitative analysis and core studies from the AIG-10 well have been performed to define both regional and fault-related fracture networks. Then laboratory thin section observations have been done to recognize the different fault rocks characterizing the fault zone components. These two kinds of approach give information on the permeability characteristics of the fault zone. To synthesize the data, a schematic conceptual 3D fluid flow modeling has been performed taking into account fault zone permeability architecture, sedimentation, fluid flow, fault vertical offset and meteoric water influx, as well as compaction water flow. This modeling allows us to fit all the data with a model where the fault segments act as a seal whereas the relays between these segments allow for the regional flow from the Peloponnese topographic highs to the coast. © 2006 Elsevier B.V. All rights reserved. Article 2006 English 00401951 10.1016/j.tecto.2006.02.022 Tectonophysics 426 31 – 59 1-2 Gulf of Corinth; Ionian Sea; Mediterranean Sea; active fault; damage mechanics; fault zone; fracture network; normal fault https://www.scopus.com/inward/record.uri?eid=2-s2.0-33749505831&doi=10.1016%2fj.tecto.2006.02.022&partnerID=40&md5=199af1f75c238134f6bb72f85580aa61 Cited by: 54 Luca Micarelli Isabelle Moretti Manon Jaubert Hakim Moulouel article IbsvonSeht2006197 A seismicity and stress field analysis of a region in NE Bavaria reveals a complex picture of seismic dislocation. The magnitudes are generally low, the strongest event recorded had a magnitude of 2.3. In the southern part of the area investigated, earthquakes occur very rarely. During the observation period of approximately four years, only four events, two of them forming a doublet, were recorded. Hypocentral depths in the southern part are considerably great (15 to 17 km) and indicate a mafic lower crust. The seismicity of the Marktredwitz area, located in the western extension of the Eger rift, is dominated by earthquake swarms that are strongly clustered in space and time. The swarms occurred at depths between 10 and 14 km. Precise relative relocations show clear planar arrangements of the hypocentres and enable to identify the orientation of active fault planes. A comparison of the structural and geomorphological settings reveals major similarities in the occurrence of earthquake swarms compared to the situation in the bordering Vogtland/NW-Bohemia swarm area. Focal mechanisms cover a wide range of faulting styles. Normal fault, strike slip and reverse fault mechanisms as well as movements along sub-horizontal planes were found. The focal mechanisms were used to invert for the stress field. The inversion results reveal an ambiguity for the state of stress in the area of investigation and allow two different interpretations: A clockwise rotation of the stress field from North to South as well as a predominance of two slightly different stress regimes are possibilities. © Springer Science+Business Media, Inc. 2006. Article 2006 English 13834649 10.1007/s10950-005-9008-5 Journal of Seismology 10 197 – 211 2 Bavaria; Central Europe; Eurasia; Europe; Germany; earthquake magnitude; earthquake swarm; focal mechanism; seismicity; stress field https://www.scopus.com/inward/record.uri?eid=2-s2.0-33748062335&doi=10.1007%2fs10950-005-9008-5&partnerID=40&md5=5258095a8b9d6fd827a8c5041aabbe8b Cited by: 9 M. Ibs-von Seht T. Plenefisch E. Schmedes article Tembe2006 We investigated the frictional properties of drill cuttings and core obtained from 1.85-3.1 km true vertical depth in the SAFOD scientific borehole in central California. Triaxial frictional sliding experiments were conducted on samples from primary lithologic traits and significant shear zones, including the inferred active trace of the San Andreas fault. The samples were deformed at room temperature under constant effective normal stresses of 10, 40, and 80 MPa with axial shortening rates of 0.01-1.0 μm s-1. The weakest samples were from shale, claystone, and siltstone units with friction coefficient μ = 0.4-0.55. Stronger samples were from quartzo-feldspathic rocks with μ ≥ 0.6. Materials tested from two shear, zones at 2560 and 3067 m measured depth had μ = 0.4-0.55 and velocity strengthening behavior consistent with fault creep at depths &lt;4 km. The coefficient of friction for bulk samples from the inferred trace of the San Andreas fault was ∼0.6. Copyright 2006 by the American Geophysical Union. 2006 English 00948276 10.1029/2006GL027626 Geophysical Research Letters 33 Department of Geosciences, State University of New York, Stony Brook, NY 11794-2100, United States; U.S. Geological Survey, 345 Middlefield Road MS/977, Menlo Park, CA 94025, United States; Department of Geography and Geosciences, Sam Houston State University, Huntsville, TX 77341, United States 23 Boreholes; Core samples; Friction; Lithology; Tectonics, Drill cuttings; Triaxial frictional sliding, Core analysis, borehole geophysics; creep; cutting; effective stress; fault; friction; San Andreas Fault; shear zone; sliding, California; North America; San Andreas; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-34547965515&doi=10.1029%2f2006GL027626&partnerID=40&md5=4e37484196b6515fd7a22a30a43333b7 cited By 45 S. Tembe D.A. Lockner J.G. Solum C.A. Morrow T.-F. Wong D.E. Moore article dAlessio2006 Heat flow measurements along much of the San Andreas fault (SAF) constrain the apparent coefficient of friction (μapp) of the fault to &lt;0.2, much lower than laboratory-derived friction values for most geologic materials. However, heat flow data are sparse near the creeping section of the SAF, a frictional "asperity" where the fault slips almost exclusively by aseismic creep. We test the hypothesis that the creeping section has a substantially higher or lower μ app than adjacent sections of the SAF. We use numerical models to explore the effects of faults with spatially and temporally heterogeneous frictional strength on the spatial distribution of surface heat flow. Heat flow from finite length asperities is uniformly lower than predicted by assuming an infinitely long fault. Over geologic time, lateral offset from strike-slip faulting produces heat flow patterns that are asymmetric across the fault and along strike. We explore a range of asperity sizes, slip rates, and displacement histories for comparing predicted spatial patterns of heat flow with existing measurements. Models with μapp ∼ 0.1 fit the data best. For most scenarios, heat flow anomalies from a frictional asperity with μapp &gt; 0.2 should be detectable even with the sparse existing observations, implying that μapp for the creeping section is as low as the surrounding SAF. Because the creeping section does not slip in large earthquakes, the mechanism controlling its weakness is not related to dynamic processes resulting from high slip rate earthquake ruptures. Copyright 2006 by the American Geophysical Union. 2006 English 21699313 10.1029/2005JB003780 Journal of Geophysical Research: Solid Earth 111 Blackwell Publishing Ltd U.S. Geological Survey, 345 Middlefield Road, Menlo Park, CA 94025, United States; Department of Earth and Planetary Science, University of California, Berkeley, CA 94720-4767, United States 5 creep; earthquake mechanism; earthquake rupture; flow pattern; friction; heat flow; San Andreas Fault https://www.scopus.com/inward/record.uri?eid=2-s2.0-33745739891&doi=10.1029%2f2005JB003780&partnerID=40&md5=bd8bbb5c807da52ab577a7ed3eed265c cited By 28 M.A. d'Alessio C.F. Williams R. Bürgmann article Tagle20061721 The three major geochemical methods for impactor identification are evaluated with respect to their potential and limitations with regards to the precise detection and identification of meteoritic material in impactites. The identification of a projectile component in impactites can be achieved by determining certain isotopic and elemental ratios in contaminated impactites. The isotopic methods are based on Os and Cr isotopic ratios. Osmium isotopes are highly sensitive for the detection of minute amounts of extraterrestrial components of even ≪0.05 wt% in impactites. However, this only holds true for target lithologies with almost no chemical signature of mantle material or young mantle-derived mafic rocks. Furthermore, this method is not currently suitable for the precise identification of the projectile type. The Cr-isotopic method requires the relatively highest projectile contamination (several wt%) in order to detect an extraterrestrial component, but may allow the identification of three different groups of extraterrestrial materials, ordinary chondrites, an enstatite chondrites, and differentiated achondrites. A significant advantage of this method is its independence of the target lithology and post-impact alteration. The use of elemental ratios, including platinum group elements (PGE: Os, Ir, Ru, Pt, Rh, Pd), in combination with Ni and Cr represents a very powerful method for the detection and identification of projectiles in terrestrial and lunar impactites. For most projectile types, this method is almost independent of the target composition, especially if PGE ratios are considered. This holds true even in cases of terrestrial target lithologies with a high component of upper mantle material. The identification of the projectile is achieved by comparison of the "projectile elemental ratio" derived from the slope of the mixing line (target-projectile) with the elemental ratio in the different types of possible projectiles (e.g., chondrites). However, this requires a set of impactite samples of various degree of projectile contamination. © The Meteoritical Society, 2006. 2006 10.1111/j.1945-5100.2006.tb00448.x Meteoritics and Planetary Science 41 1721-1735 Department of Geology, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium; Museum für Naturkunde Mineralogie, Humboldt-Universität zu Berlin, D-10099 Berlin, Germany 11 https://www.scopus.com/inward/record.uri?eid=2-s2.0-33751372115&doi=10.1111%2fj.1945-5100.2006.tb00448.x&partnerID=40&md5=fa8b9cfe110d653fd7ee7f98171772fa cited By 69 R. Tagle L. Hecht article An2006851 The intensive geophysical survey of Qinghai Lake reveals the buried depth of lake sediments and their distribution features. The result indicates that there are three important interphases of Qinghai Lake sediments: T1 is the rife interphase of the lake, above which sediments are spread all over the lake basin with roughly the same thickness; T5 is the interphase from which the neotectonic sedimentary cycle begins, and its above sedimentary environment is relatively stable; Tg is the base of the lake basin. Five west-northwest (WNW) fault belts defined the tectonic structure of Qinghai Lake basin: the central hunch around Haixin Shan with two subbasins both in its north and south. The thickness of the lake sediments varies at different places, the thickest sediments are found within the two subbasins. According to the depth that the Sparker System can reach, sediment in the northern subbasin is deeper than 560 m, while sediment in the southern subbasin is deeper than 700 m. The correlation between the seismic sequence stratigraph and the lithology of onshore core shows that Qinghai Lake sediments consist of muddy silt, clay silt, silty clay, gravel silty clay, etc. © Science in China Press 2006. Article 2006 English 18622801 10.1007/s11430-006-0851-1 Science in China, Series D: Earth Sciences 49 851 – 861 8 Asia; China; Eurasia; Far East; Qinghai; Qinghai Lake; Clay; Geophysical prospecting; Lithology; Sedimentology; Sediments; Seismology; Stratigraphy; Tectonics; lacustrine deposit; lithology; neotectonics; sediment thickness; sedimentary sequence; sedimentary structure; seismic survey; Fault belts; Neotectonic sedimentary cycle; Lakes https://www.scopus.com/inward/record.uri?eid=2-s2.0-33751002352&doi=10.1007%2fs11430-006-0851-1&partnerID=40&md5=09fe92863bba5da92a78d00f1d98faac Cited by: 38 ZhiSheng An Ping Wang Ji Shen Yixiang Zhang Peizhen Zhang Sumin Wang Xiaoqiang Li Qianli Sun YouGui Song Li Al Yechun Zhang Shaoren Jiang Xingqi Liu Yong Wang article Fujimitsu2006373 The Unzen Scientific Drilling Project (USDP) had been conducted by the Science and Technology Agency (FY1999-2000) and the Ministry of Education, Culture, Sports, Science and Technology, Japan (FY2001-2004). In this project, one of the objectives of our study was to construct a comprehensive hydrothermal model of beneath Unzen Volcano by using a numerical simulation. Four large geothermal systems are known in the Shimabara Peninsula (Obama hot springs, Unzen fumarolic field, Shimabara hot springs and the West Unzen High Temperature Body [WUHTB]). Three pressure source locations (“Sources A”, “B” and “C” from shallow to the deep) were determined by geodetic data during the 1990-95 eruption. Source C is located at about 8 km deep at WUHTB, and is considered to be a magma reservoir. We attempted to explain the existence mechanism of the four geothermal systems from the large-scale structures (the topography of the Shimabara Peninsula and Unzen Graben) and the various heat sources. We first set a heat source around Source C and changed its position and size. This numerical model produced the upflow zones at the Obama and Shimabara hot springs and WUHTB; however the Unzen fumarolic field became a recharge area. This result indicated that it would be difficult to develop the Unzen fumarolic field only by Source C ; therefore, we set another heat source just beneath the fumarolic field. Consequently, two heat sources beneath WUHTB and the Unzen fumarolic field are involved in the formation of the four hydrothermal systems in the Shimabara Peninsula. Especially, the heat source beneath the Unzen fumarolic field is essential to generate heat discharges at the fumarolic field. © 2006, THE GEOTHERMAL RESEARCH SOCIETY OF JAPAN. All rights reserved. 2006 English 03886735 10.11367/grsj1979.28.373 Journal of the Geothermal Research Society of Japan 28 373-382 Department of Earth Resources Engineering, Faculty of Engineering, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan, Japan; Department of Earth Resources Engineering, Graduate School of Engineering, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan, Japan 4 https://www.scopus.com/inward/record.uri?eid=2-s2.0-77955844565&doi=10.11367%2fgrsj1979.28.373&partnerID=40&md5=e57ea16723d655398f4a93ae010435cd cited By 2 Y. Fujimitsu S. Ehara R. Oki article Schwamborn2006259 An accumulation terrace close to the El'gygytgyn Impact Crater in northeastern Siberia contains stratigraphic and periglacial evidence of the paleoenvironmental and paleoclimatic history and permafrost dynamics during late Quaternary time. A succession of paleo active-layer deposits that mirror environmental changes records periods favorable for the establishment and growth of ice-wedge polygonal networks and sediment variations. These two elements of the periglacial landscape serve as complementary paleoenvironmental archives that can be traced back to ∼ 14,000 cal yr BP. The slope sediments and the ground ice contained therein have prominent relative maxima and minima in properties (grain size, total organic content, oxygen isotopes). They document a regional early Holocene thermal maximum at about 9000 cal yr BP, followed by a transition to slightly cooler conditions, and a subsequent transition to slightly warmer conditions after about 4000 cal yr BP. Results from sedimentary analysis resemble morphological and geochemical (oxygen and hydrogen isotopes) results from ice wedge studies, in which successive generations of ice-wedge polygonal networks record warmer winters in late Holocene time. Moreover, peaks of light soluble cation contents and quartz-grain surface textures reveal distinct traces of cryogenic weathering. We propose a conclusive sedimentation model illustrating terrace formation in a permafrost terrain. © 2006 Elsevier B.V. All rights reserved. 2006 English 00335894 10.1016/j.yqres.2006.06.007 Quaternary Research 66 259-272 Alfred Wegener Institute for Polar and Marine Research, Telegrafenberg A43, D-14473 Potsdam, Germany; Arctic and Antarctic Research Institute, Bering Street, 199397 St. Petersburg, Russian Federation 2 environmental change; frozen ground; Hypsithermal; paleoclimate; paleoenvironment; periglacial landform; permafrost, Eurasia; Siberia https://www.scopus.com/inward/record.uri?eid=2-s2.0-33749633176&doi=10.1016%2fj.yqres.2006.06.007&partnerID=40&md5=751fc29fdaabd46153b7b809a430a896 cited By 52 G. Schwamborn H. Meyer G. Fedorov L. Schirrmeister H.-W. Hubberten article Hirono2006 The Taiwan Chelungpu-fault Drilling Project (TCDP) was undertaken in 2002 to investigate the faulting mechanism of the 1999 Taiwan Chi-Chi earthquake. Hole B penetrated the Chelungpu fault, and recovered core samples from between 948.42 m and 1352.60 m depth. Three zones, marked 1136mFZ, 1194mFZ and 1243mFZ, were recognized in the core samples as active fault-zones within the Chelungpu fault. Multi-Sensor Core Logger measurements revealed lower densities and higher magnetic susceptibilities within the black gouge zones in all three fault zones. Even though the fault zone that slipped during the 1999 earthquake has not been identified, higher magnetic susceptibilities indicate that frictional heating has taken place in the Chelungpu fault. Copyright 2006 by the American Geophysical Union. 2006 English 00948276 10.1029/2006GL026133 Geophysical Research Letters 33 Kochi Institute for Core Sample Research, Japan Agency for Marine-Earth Science and Technology, Nankoku, Japan; Department of Natural Environmental Science, Faculty of Science, Kochi University, Kochi, Japan; Department of Geology and Mineralogy, Graduate School of Science, Kyoto University, Kyoto, Japan; Institute for Geo-Resources and Environment, National Institute of Advanced Industrial Science and Technology, Tsukuba, Japan; Center for Deep Earth Exploration, Japan Agency for Marine-Earth Science and Technology, Yokohama, Japan; Institute for Research on Earth Evolution, Japan Agency for Marine-Earth Science and Technology, Yokosuka, Japan; Center for Advanced Marine Core Research, Kochi University, Kochi, Japan; Department of Geosciences, National Taiwan University, Taipei, Taiwan; Institute of Geophysics, National Central University, Jhongli, Taiwan; Center for Deep Earth Exploration, Japan Agency for Marine-Earth Science and Technology, 3173-25 Showa-machi, Kanazawa-ku, Yokohama, 236-0001, Japan; Department of Natural Environmental Science, Faculty of Science, Kochi University, 2-5-1 Akebono-cho, Kochi 780-8520, Japan; Kochi Institute for Core Sample Research, Japan Agency for Marine-Earth Science and Technology, Nankoku 783-8502, Japan; Institute of Geophysics, National Central University, Jhongda Road, Jhongli 32001, Taiwan; Institute for Research on Earth Evolution, Japan Agency for Marine-Earth Science and Technology, 2-15 Natsushima-cho, Yokosukashi, 237-0061, Japan; Institute for Geo-Resources and Environment, National Institute of Advanced Industrial Science and Technology, Tsukuba, 305-8567, Japan; Center for Advanced Marine Core Research, Kochi University, 2-5-1 Akebono-cho, Kochi 780-8520, Japan; Department of Geology and Mineralogy, Graduate School of Science, Kyoto University, Yoshida-Honmachi, Sakyo-ku, Kyoto 606-8501, Japan; Department of Geosciences, National Taiwan University, Roosevelt Road, Taipei, 106, Taiwan 15 Earthquakes; Heating; Magnetic susceptibility; Project management; Sensors; Tribology, Chemical properties; Fault rocks, Geomorphology, Chi-Chi earthquake 1999; fault gouge; magnetic susceptibility; physicochemical property; rock, Asia; Eurasia; Far East; Taiwan https://www.scopus.com/inward/record.uri?eid=2-s2.0-33845670299&doi=10.1029%2f2006GL026133&partnerID=40&md5=3f64f0bd58d94891df45e144925e67c7 cited By 79 T. Hirono W. Lin E.-C. Yeh W. Soh Y. Hashimoto H. Sone O. Matsubayashi K. Aoike H. Ito M. Kinoshita M. Murayama S.-R. Song K.-F. Ma J.-H. Hung C.-Y. Wang Y.-B. Tsai article Prokopenko20051 Editorial 2005 English 10406182 10.1016/j.quaint.2004.11.002 Quaternary International 136 Elsevier Ltd 1 – 4 1 SPEC. ISS. atmospheric circulation; lacustrine deposit; paleolimnology https://www.scopus.com/inward/record.uri?eid=2-s2.0-17144415845&doi=10.1016%2fj.quaint.2004.11.002&partnerID=40&md5=494581e40df8cea2e69e731bf6ef6b25 Cited by: 3 A. Prokopenko N. Catto article Zhang2005857 The Qinglongshan O- and H-isotope anomaly occurs within a coesite-bearing, eclogite-facies regional metamorphic belt in Eastern China near Donghai in Jiangsu province. The anomaly is defined by low values of δ18O and δD. Garnets from eclogite have δ18O as low as -11‰ and rutiles are -15‰ (VSMOW). Phengites have δD of -120‰ (VSMOW). The anomaly is Neoproterozoic in age. Surface outcrops of coesite-eclogite-facies rocks with unusually low δ18O and δD values extend over an area of at least 1600 km2. The Chinese Continental Scientific Drilling project has made it possible to investigate the depth of the Qinglongshan anomaly and to measure an O-isotope profile across a garnet peridotite body sandwiched between crustal rocks. New O-isotope analyses of minerals separated from drill core gneisses, eclogites, amphibolite, and quartzite verify that the Qinglongshan O-isotope anomaly extends to a depth of at least 432 m. Crustal rocks with unusually low δ18O form both the hanging- and foot-walls of a 100 m thick, fault-bounded, garnet peridotite body intersected by the drill. Minerals of the garnet peridotite body have δ18O values indistinguishable from mantle nodules and megacrysts. The garnet peridotites may have originated from enriched mantle sources in sub-cratonic lithosphere, isolated from mantle convection. This origin is consistent with the collision of the Archean Sino-Korean craton with the Yangtze plate, consequent subduction, and UHP metamorphism. The garnet peridotite was transported from the mantle and emplaced into UHP crustal rocks during Triassic subduction and cratonic collision. Article 2005 English 0003004X 10.2138/am.2005.1650 American Mineralogist 90 Mineralogical Society of America 857 – 863 5-6 Asia; China; Donghai; Eastern Hemisphere; Eurasia; Far East; Jiangsu; World; Drills; Exploratory geochemistry; Garnets; Infill drilling; Isotopes; Metamorphic rocks; Oxide minerals; Oxygen; Silica; Structural geology; Coesite-eclogite; Continental scientific drillings; Garnet peridotite; Isotope anomalies; Jiangsu province; Mantle convection; Metamorphic belts; Sino-Korean craton; Chinese Continental Scientific Drilling Project; collision zone; metamorphic rock; oxygen isotope; Core drilling https://www.scopus.com/inward/record.uri?eid=2-s2.0-20444449621&doi=10.2138%2fam.2005.1650&partnerID=40&md5=906b7b27de85037a145686e5c722c411 Cited by: 40 Ze M. Zhang D. Rumble J.G. Liou Yi L. Xiao Yong J. Gao article Inoue2005106 This paper presents an overview of the pressure drawdown test and the thermal stimulation test at the Mallik 2002 gas hydrate research well, conducted in February and March 2002. Pressure drawdown tests were conducted on methane hydrate, free gas, and water intervals, using Schlumberger's Modular Formation Dynamics Tester (MDT) wireline tool. The thermal stimulation test was designed to increase the in-situ temperature of a well-defined and constrained methane hydrate reservoir above the methane hydrate stability point, while maintaining constant pressure. The objectives of the production tests were to confirm the feasibility of production of natural gas from methane hydrate deposits by depressurization and thermal stimulation, and to collect sufficient data to determine relevant methane hydrate formation properties. The production tests were successful in that significant amounts of the in-situ dissociation properties, as well as other scientific measurements, were obtained. 2005 English 09168753 Nihon Enerugi Gakkaishi/Journal of the Japan Institute of Energy 84 106-111 Japan Oil, Gas and Metals National Corporation, 1-2-2 Hamada, Mihama-ku, Chiba 261-0025, Japan 2 Methane; Natural gas; Natural gas well drilling; Production, Mallik, Canada; MDT; Methane hydrates; Pressure drawdown tests; Production tests; Thermal stimulation tests, Gas hydrates https://www.scopus.com/inward/record.uri?eid=2-s2.0-19944402198&partnerID=40&md5=3812fe5dfa90f5264d37b3d7a951e3d1 cited By 2 T. Inoue article Oye2005751 To identify and constrain the target zone for the planned SAFOD Main Hole through the San Andreas Fault (SAF) near Parkfield, California, a 32-level three-component (3C) geophone string was installed in the Pilot Hole (PH) to monitor and improve the locations of nearby earthquakes. The orientation of the 3C geophones is essential for this purpose, because ray directions from sources may be determined directly from the 3D particle motion for both P and S waves. Due to the complex local velocity structure, rays traced from explosions and earthquakes to the PH show strong ray bending. Observed azimuths are obtained from P-wave polarization analysis, and ray tracing provides theoretical estimates of the incoming wave field. The differences between the theoretical and the observed angles define the calibration azimuths. To investigate the process of orientation with respect to the assumed velocity model, we compare calibration azimuths derived from both a homogeneous and 3D velocity model. Uncertainties in the relative orientation between the geophone levels were also estimated for a cluster of 36 earthquakes that was not used in the orientation process. The comparison between the homogeneous and the 3D velocity model shows that there are only minor changes in these relative orientations. In contrast, the absolute orientations, with respect to global North, were significantly improved by application of the 3D model. The average data residual decreased from 13° to 7°, supporting the importance of an accurate velocity model. We explain the remaining residuals by methodological uncertainties and noise and with errors in the velocity model. 2005 English 00371106 10.1785/0120040130 Bulletin of the Seismological Society of America 95 751-758 NORSAR, 2027 Kjeller, Norway; U.S. Geological Survey, 345 Middlefield Road, Menlo Park, CA, United States 2 Calibration; Data reduction; Earthquakes; Installation, California, USA; Pilot Hole (PH); San Andreas Fault (SAF); Three-component (3C) geophones, Seismology, geophone; orientation; seismometry, California; North America; Parkfield; United States; Western Hemisphere; World https://www.scopus.com/inward/record.uri?eid=2-s2.0-20444395420&doi=10.1785%2f0120040130&partnerID=40&md5=29d5d82f99cf07746f5936f60db81585 cited By 14 V. Oye W.L. Ellsworth article Lu20051 Gas hydrate samples recovered from a cold vent field offshore Vancouver Island were studied in detail both by macroscopic observations and instrumental methods (powder X-ray diffraction method (PXRD), nuclear magnetic resonance (NMR), and Raman spectroscopy). It was found that gas hydrates were massive from 2.64 to 2.94 m below seafloor (mbsf), elongated, nodular and tabular from 4.60 to 4.81 mbsf, and vein-like from 5.48 to 5.68 mbsf, showing a trend of decreasing hydrate content with increasing depth. All samples were determined to be structure I hydrate from PXRD, NMR, and Raman spectroscopies. The hydration numbers were estimated to be 6.1 ± 0.2 on average as determined from the methane distribution over the cage sites from NMR and Raman analytical results. Estimates of conversion levels indicated that ∼78% of the water in the massive samples was hydrate, down to a low value of ∼0.4% for the pore hydrate samples. The results are compared with measurements on synthetic hydrates and samples recovered from below the permafrost on the Mallik site. Differences in methane content and lattice parameters for synthetic and natural samples are relatively minor. Additional work is needed to address the presence of minor gas components and the heterogeneity of natural hydrate samples. Copyright 2005 by the American Geophysical Union. 2005 English 21699313 10.1029/2005JB003900 Journal of Geophysical Research: Solid Earth 110 Blackwell Publishing Ltd 1-9 Steacie Institute for Molecular Sciences, National Research Council of Canada, 100 Sussex Drive, Ottawa, Ont. K1A 0R6, Canada; Pacific Geoscience Center, Geological Survey of Canada, P.O. Box 6000, Sidney, BC V8L 4B2, Canada; School of Earth and Ocean Sciences, University of Victoria, Victoria, BC V8W 2Y2, Canada 10 cold seep; gas hydrate, British Columbia; Canada; North America; Vancouver Island https://www.scopus.com/inward/record.uri?eid=2-s2.0-29444439032&doi=10.1029%2f2005JB003900&partnerID=40&md5=2c4e6cc3a8fd4eb2426f56c3fbebe327 cited By 59 H. Lu I. Moudrakovski M. Riedel G. Spence R. Dutrisac J. Ripmeester F. Wright S. Dallimore article Uchida200593 The Mallik 5L-38 gas hydrate production research well was drilled to 1166 m early in 2002, and abundant gas-hydrate-bearing cores were successfully retrieved from a variety of sediments. Gas hydrate-dominant layers were identified at depths of 889 to 1108 m. Gas-hydrate-bearing strata typically range from 10 cm to a few meters in thickness, and gas hydrate saturations in most gas hydrate layers were quite high. Pore-space hydrate is very small in size and fills the intergranular porosity of sandy sediments. The X-ray CT images of gas-hydrate-bearing sediments always show very uniform CT values. Those values in some parts of the sediment samples suggest that the methane hydrate contents range from 23 to 36 vol.% of the sample, which indicate high methane hydrate saturations in the intergranular porosity of the sand samples. Most of the gas hydrates fill the intergranular pore systems of sands, which are derived from channels and crevasse splay/levee deposits. Gas hydrate is less frequently found in siltstones and mudstones from interdistributary bay and overbank deposits. Measurements of water permeability were undertaken, initially keeping the hydrate stable at 10 °C by pressurizing, and then depressurizing gradually. Initial water permeabilities of gas hydrate/ice filled sands range from 1 to 5 millidarcy. Pore-space hydrate was observed to occur primarily in fine- to medium-grained arenite sands. X-ray diffraction and Raman spectroscopy measurements showed that pore-space hydrates contained in sands are mainly Structure I. P-wave velocities of those sands, measured over the interval -20 to 5 °C, decrease from 4 to 3 km/sec as water ice melted, S-wave velocities decrease from about 2.5 km/sec at -20 °C to about 1.5 km/sec at 5°C. Measurements of mechanical strength and electrical resistivity were also undertaken. 2005 English 09168753 Nihon Enerugi Gakkaishi/Journal of the Japan Institute of Energy 84 93-98 JAPEX Research Center, 1-2-1 Hamada, Mihama, Chiba 261-0025, Japan 2 Computerized tomography; Deposits; Electric resistance; Gas hydrates; Geology; Grain size and shape; Natural gas well drilling; Porosity; Raman spectroscopy; Sediments; Strength of materials; X ray diffraction, Mallik, Canada; Methane hydrate; P- & S-wave velocity; Pore-space hydrates, Natural gas https://www.scopus.com/inward/record.uri?eid=2-s2.0-19944395525&partnerID=40&md5=50fbd5dc72f1811d2ac8ccbbe8216496 cited By 0 T. Uchida article Ivanov2005381 Multi-ring impact basins have been found on the surfaces of almost all planetary bodies in the Solar system with solid crusts. The details of their formation mechanism are still unclear. We present results of our numerical modeling of the formation of the largest known terrestrial impact craters. The geological and geophysical data on these structures accumulated over many decades are used to place constraints on the parameters of available numerical models with a dual purpose: (i) to choose parameters in available mechanical models for the crustal response of planetary bodies to a large impact and (ii) to use numerical modeling to refine the possible range of original diameters and the morphology of partially eroded terrestrial craters. We present numerical modeling results for the Vredefort, Sudbury, Chicxulub, and Popigai impact craters and compare these results with available geological and geophysical information. © 2005 Pleiades Publishing, Inc. 2005 10.1007/s11208-005-0051-0 Solar System Research 39 381-409 Institute for Dynamics of Geospheres, Russian Academy of Sciences, Leninskii pr. 38, Moscow, 117979, Russian Federation 5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-27144546662&doi=10.1007%2fs11208-005-0051-0&partnerID=40&md5=0edd01acdae9945c8fe2689c9e3c0953 cited By 153 B.A. Ivanov article Chang2005402 We conducted laboratory rock strength experiments in two ultra-fine-grained brittle rocks, hornfels and metapelite, which together are the major constituent of the Long Valley Caldera (California, USA) basement in the 2025-2996 m depth range. Both rocks are banded, and have very low porosity. Uniaxial compression tests at different orientations with respect to banding planes reveal that while the hornfels compressive strength is nearly isotropic, the metapelite possesses distinct anisotropy. Conventional triaxial tests in these rocks reveal that their respective strengths in a specific orientation increase approximately linearly with confining pressure. True triaxial compression experiments in specimens oriented at a consistent angle to banding, in which the magnitudes of the least (σ3) and the intermediate (σ2) principal stresses are different but kept constant during testing while the maximum principal stress is increased until failure, exhibit a behavior unlike that previously observed in other rocks under similar testing conditions. For a given magnitude of σ3, compressive strength σ1 does not vary significantly in both Long Valley rock types, regardless of the applied σ2, suggesting little or no intermediate principal stress effect. Strains measured in all three principal directions during loading were used to obtain plots of σ1 versus volumetric strain. These are consistently linear almost to the point of rock failure, suggesting no dilatancy. The phenomenon was corroborated by SEM inspection of failed specimens that showed no microcrack development prior to the emergence of one through-going shear failure plane steeply dipping in the σ3 direction. The strong dependency of compressive strength on the intermediate principal stress in other crystalline rocks was found to be related to microcrack initiation upon dilatancy onset, which rises with increased σ2 and retards the failure process. We infer that strength independence of σ2 in the Long Valley rocks derives directly from their non-dilatant deformation. © 2005 Elsevier Ltd. All rights reserved. 2005 English 13651609 10.1016/j.ijrmms.2005.01.002 International Journal of Rock Mechanics and Mining Sciences 42 Elsevier BV 402-414 Dept. of Mat. Science/Engineering, Geological Engineering Program, University of Wisconsin, 1509 University Avenue, Madison, WI 53706-1595, United States; Department of Geology, Chungnam National University, Daejeon, South Korea 3 Compressive strength; Crack initiation; Deformation; Failure analysis; Porosity; Strain; Strength of materials; Volumetric analysis, Brittle rocks; Metapelite; Rock strength; Volumetric strain, Rocks, deformation; triaxial test; volcanic rock, California; Long Valley; North America; United States; Western Hemisphere; World https://www.scopus.com/inward/record.uri?eid=2-s2.0-15544377807&doi=10.1016%2fj.ijrmms.2005.01.002&partnerID=40&md5=cc720f419660d49934a2e782ebfc6f5c cited By 61 C. Chang B. Haimson article Shah2005417 We present high-resolution gravity and magnetic field survey results over the 85-km-diameter Chesapeake Bay impact structure. Whereas a continuous melt sheet is anticipated at a crater this size, shallow-source magnetic field anomalies of ∼100 nT instead suggest that impact melt pooled in kilometer-scaled pockets surrounding the base of a central peak. A central anomaly of ∼300 nT may represent additional melt or rock that underwent shock-induced remagnetization. Models predict that the total volume of the melt ranges from ∼0.4 to 10 km3, a quantity that is several orders of magnitude smaller than expected for an impact structure this size. However, this volume is within predictions given a transient crater of diameter of 20-40 km for a target covered with water and sedimentary deposits such that melt fragments were widely dispersed at the time of impact. Gravity data delineate a gently sloping inner basin and a central peak via a contrast between crystalline and sedimentary rock. Both features are ovoid, oriented parallel to larger preimpact basement structures. Conceptual models suggest how lateral differences in rock strength due to these preimpact structures helped to shape the crater's morphology during transient-crater modification. © 2005 Geological Society of America. 2005 English 00917613 10.1130/G21213.1 Geology 33 417-420 Naval Research Laboratory, Washington, DC 20375, United States; U.S. Geological Survey, Reston, VA 20192, United States; Applied Physics Lab., Johns Hopkins University, Laurel, MD 20723, United States 5 Chesapeake bay impact structures; Craters; Melt fragments; Remagnetization, Gravitation; Magnetic fields; Magnetization; Melting; Morphology; Rocks, Tectonics, gravity survey; impact structure; magnetic survey; remagnetization; shock metamorphism, Chesapeake Bay; North America; United States; Western Hemisphere; World https://www.scopus.com/inward/record.uri?eid=2-s2.0-18944362488&doi=10.1130%2fG21213.1&partnerID=40&md5=6298ac1ae137e0211bc65f8aa65a53fd cited By 27 A.K. Shah J. Brozena P. Vogt D. Daniels J. Plescia article Abouchami2005851 The two parallel chains of Hawaiian volcanoes ('Loa' and 'Kea') are known to have statistically different but overlapping radiogenic isotope characteristics. This has been explained by a model of a concentrically zoned mantle plume, where the Kea chain preferentially samples a more peripheral portion of the plume. Using high-precision lead isotope data for both centrally and peripherally located volcanoes, we show here that the 'two trends have very little compositional overlap and instead reveal bilateral, non-concentric plume zones, probably derived from the plume source in the mantle. On a smaller scale, along the Kea chain, there are isotopic differences between the youngest lavas from the Mauna Kea and Kilauea volcanoes, but the 550-thousand-year-old Mauna Kea lavas are isotopically identical to Kilauea lavas, consistent with Mauna Kea's position relative to the plume, which was then similar to that of present-day Kilauea. We therefore conclude that narrow (less than 50 kilometres wide) compositional streaks, as well as the larger-scale bilateral zonation, are vertically continuous over tens to hundreds of kilometres within the plume. 2005 English 00280836 10.1038/nature03402 Nature 434 851-856 Max-Planck-Institut für Chemie, Postfach 3060, 55020 Mainz, Germany; Massachusetts Inst. of Technology, Cambridge, MA 02139, United States; Department of Geological Sciences, Rutgers University, New Brunswick, NJ 08903, United States 7035 Composition; Geographical regions; Geophysics; Lead; Volcanoes, Isotopy; Lead isotopes; Mantle plume; Radiogenic isotopes, Radioisotopes, isotope; lead, isotopic composition; lava flow; lead; mantle plume, accuracy; article; chemical composition; evolution; geographic distribution; parameter; plume; priority journal; radioactivity; regression analysis; sampling; technique; theoretical model; United States; volcano, Hawaii [(ISL) Hawaiian Islands]; Hawaii [United States]; Hawaiian Islands; Mauna Kea; Mauna Loa; North America; oceanic regions; Pacific islands; Pacific Ocean; United States; Western Hemisphere; World https://www.scopus.com/inward/record.uri?eid=2-s2.0-17644365383&doi=10.1038%2fnature03402&partnerID=40&md5=209c60037850d04b4ae9f90035d8f4b1 cited By 204 W. Abouchami A.W. Hofmann S.J.G. Galer F.A. Frey J. Eisele M. Felgenson article Masaitis2005509 Impact cratering produces not only craterform topographic features, but also structural disturbances at the site of impact, and a spectrum of transformed and newly formed rocks. The term 'coptogenesis' (from the Greek χoπτo, to destroy by shock) may be used collectively to describe the impact process-a process fundamental to all cosmic bodies. Principal coptogenic topographic features of terrestrial impact craters may be subdivided into excavational, structural and accumulative landforms, most of which subsequently experience various processes of degradation. Nevertheless, the original shape of craters may in some cases be reconstructed and compared with fresh craters on other planets. An immediate conformity between the pre-erosional topographic features of complex terrestrial craters, and the morphostructural elements of their erosional remnants, is not a standing rule. Geological observations show that the inner structure of the proximal crater fill and distal ejecta are characterised by pseudo-stratification and that these materials represent a group of facies of impact-derived and impact-related, or coptogenic, lithologies. The study of these facies allows us to distinguish various facies settings of rock-forming processes. Impact lithologies, or coptogenic rocks, may be systematised and classified using the principles adopted by igneous petrology and volcanology. Appropriate geological methods and approaches should be applied to the investigation of terrestrial impact craters, including their identification, mapping, and study of their various physiographic, structural, and lithological features. © Geological Society of Australia. 2005 10.1080/08120090500170427 Australian Journal of Earth Sciences 52 509-528 Karpinsky Geological Institute, Sredny prospect 74, St Petersburg 199106, Russian Federation 4-5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-27344446833&doi=10.1080%2f08120090500170427&partnerID=40&md5=7d46ea45ba9f3dc1845bebe8b52caafd cited By 11 V.L. Masaitis article Guerin2005 Recent sonic and seismic data in gas hydrate-bearing sediments have indicated strong waveform attenuation associated with a velocity increase, in apparent contradiction with conventional wave propagation theory. Understanding the reasons for such energy dissipation could help constrain the distribution and the amounts of gas hydrate worldwide from the identification of low amplitudes in seismic surveys. A review of existing models for wave propagation in frozen porous media, all based on Biot's theory, shows that previous formulations fail to predict any significant attenuation with increasing hydrate content. By adding physically based components to these models, such as cementation by elastic shear coupling, friction between the solid phases, and squirt flow, we are able to predict an attenuation increase associated with gas hydrate formation. The results of the model agree well with the sonic logging data recorded in the Mallik 5L-38 Gas Hydrate Research Well. Cementation between gas hydrate and the sediment grains is responsible for the increase in shear velocity. The primary mode of energy dissipation is found to be friction between gas hydrate and the sediment matrix, combined with an absence of inertial coupling between gas hydrate and the pore fluid. These results predict similar attenuation increase in hydrate-bearing formations over most of the sonic and seismic frequency range. Copyright 2005 by the American Geophysical Union. 2005 English 15252027 10.1029/2005GC000918 Geochemistry, Geophysics, Geosystems 6 Borehole Research Group, Lamont-Doherty Earth Observatory, Route 9W, Palisades, NY 10964, United States 7 https://www.scopus.com/inward/record.uri?eid=2-s2.0-33646721772&doi=10.1029%2f2005GC000918&partnerID=40&md5=acb2770a38cf857f73da63ae9f1afe3e cited By 69 G. Guerin D. Goldberg article Zhang20053213 Microbial communities in ultra-high-pressure (UHP) rocks and drilling fluids from the Chinese Continental Scientific Drilling Project were characterized. The rocks had a porosity of 1 to 3.5% and a permeability of ∼0.5 mDarcy. Abundant fluid and gas inclusions were present in the minerals. The rocks contained significant amounts of Fe2O3, FeO, P2O5, and nitrate (3 to 16 ppm). Acridine orange direct counting and phospholipid fatty acid analysis indicated that the total counts in the rocks and the fluids were 5.2 × 103 to 2.4 × 10 4 cells/g and 3.5 x 108 to 4.2 × 109 cells/g, respectively. Enrichment assays resulted in successful growth of thermophilic and alkaliphilic bacteria from the fluids, and some of these bacteria reduced Fe(III) to magnetite. 16S rRNA gene analyses indicated that the rocks were dominated by sequences similar to sequences of Proteobacteria and that most organisms were related to nitrate reducers from a saline, alkaline, cold habitat; however, some phylotypes were either members of a novel lineage or closely related to uncultured clones. The bacterial communities in the fluids were more diverse and included Proteobacteria, Bacteroidetes, gram-positive bacteria, Planctomycetes, and Candidatus taxa. The archaeal diversity was lower, and most sequences were not related to any known cultivated species. Some archaeal sequences were 90 to 95% similar to sequences recovered from ocean sediments or other subsurface environments. Some archaeal sequences from the drilling fluids were >93% similar to sequences of Sulfolobus solfataricus, and the thermophilic nature was consistent with the in situ temperature. We inferred that the microbes in the UHP rocks reside in fluid and gas inclusions, whereas those in the drilling fluids may be derived from subsurface fluids. Copyright © 2005, American Society for Microbiology. All Rights Reserved. Article 2005 English 00992240 10.1128/AEM.71.6.3213-3227.2005 Applied and Environmental Microbiology 71 3213 – 3227 6 Atmospheric Pressure; Bacteria; China; Crenarchaeota; Culture Media; DNA, Archaeal; DNA, Bacterial; DNA, Ribosomal; Ecosystem; Geologic Sediments; Geology; Minerals; Molecular Sequence Data; Phylogeny; Polymorphism, Restriction Fragment Length; RNA, Ribosomal, 16S; Sequence Analysis, DNA; Asia; China; Eastern Hemisphere; Eurasia; Far East; World; Archaea; Bacteroidetes; Candidatus; Planctomycetes; Posibacteria; Proteobacteria; Sulfolobus solfataricus; Bacteria; Bioassay; Drilling; Fatty acids; High pressure effects; Iron; Magnetite; Phosphorus compounds; Porosity; RNA; Rocks; ferric ion; magnetite; nitrate; RNA 16S; sodium chloride; microbial community; alkalinity; article; bacterial flora; bacterial gene; Bacteriodetes; bacterium; Candidatus; China; controlled study; drill; gene sequence; geographic distribution; Gram positive bacterium; microbial diversity; nonhuman; nucleotide sequence; Planctomycetes; Proteobacteria; rock; Sulfolobus solfataricus; thermophilic bacterium; unindexed sequence; Gas inclusion; Microbial diversity; Prototypes; Ultra-high-pressure (UHP) rocks; Biodiversity https://www.scopus.com/inward/record.uri?eid=2-s2.0-20444426140&doi=10.1128%2fAEM.71.6.3213-3227.2005&partnerID=40&md5=70292c0307b8b1db3bfb045c00786194 Cited by: 65; All Open Access, Green Open Access Gengxin Zhang Hailiang Dong Zhiqin Xu Donggao Zhao Chuanlun Zhang article Kurihara2005112 The results of the thermal production test and Modular Formation Dynamics Tester (MDT) tests conducted at the Mallik 5L-38 gas hydrate production research well were analyzed, using the numerical simulator coded for gas hydrate reservoirs. The reservoir models were constructed as a series of grid blocks. In the simulation for the thermal production test, the reservoir model was tuned through history matching, by introducing the concept that part of the circulating hot water might have invaded into the reservoir, which resulted in the excellent agreement between observed and simulated performances. Using the history-matched reservoir model, sensitivity simulation and prediction of future performances were conducted to examine the effects of uncertain reservoir parameters and the gas hydrate dissociation/production methods on the recovery of gas from the Mallik reservoir. In the MDT test simulation, to investigate the applicability of conventional pressure transient test analysis methods, bottomhole pressure responses during MDT tests in hypothetical and actual gas hydrate zones were simulated and were then analyzed by the conventional analysis methods. This study revealed that conventional methods might indicate the average effective permeability over the area of gas hydrate dissociation while the estimation of the radius of gas hydrate dissociation was quite imprecise. 2005 English 09168753 Nihon Enerugi Gakkaishi/Journal of the Japan Institute of Energy 84 112-118 Japan Oil Engineering Company Limited, 1-7-3 Kachidoki, Chuo-ku, Tokyo 104-0054, Japan 2 Computer simulation; Mathematical models; Natural gas well drilling; Sensitivity analysis, History matching; Methane hydrates; Modular formation dynamics tester (MDT); Thermal methods; Well tests, Gas hydrates https://www.scopus.com/inward/record.uri?eid=2-s2.0-19944410511&partnerID=40&md5=21029701e5fdad7a37d1965e9dc6fcef cited By 0 M. Kurihara article Okubo2005743 On September 18, 2002, we conducted a high-resolution, low-altitude helicopter-bome aeromagnetic survey at two flight altitudes, using spiral trajectories for the first time, over Unzen Volcano in the framework of the Unzen Scientific Drilling Project (USDP). This study obtained more detailed and new information than the previous aeromagnetic studies in Unzen volcano about the geological features, for understanding the history and eruption mechanism of the Unzen volcano. Therefore, we conducted a magnetization intensity mapping on the volcano, on the assumption that the magnetic anomalies are caused by the terrain magnetized in the same direction as the present Earth's magnetic field and the magnetization intensity varies only laterally. This map shows good agreement with the geologic features, especially the hydrothermal alteration zone and the collapsed pyroclastic deposits. In addition, even in the area covered by lavas, the magnetization intensities show various values corresponding to each eruption event. It may be considered that the differences in magnetic properties reflect different oxygen fugacity in rocks during their cooling time period. Local magnetization lows on Heisei-Shinzan suggest that the Heisei lava produced by the 1991-1995 eruption has not yet been cooled enough. Copyright © The Society of Geomagnetism and Earth, Planetary and Space Sciences (SGEPSS); The Seismological Society of Japan; The Volcanological Society of Japan; The Geodetic Society of Japan; The Japanese Society for Planetary Sciences; TERRAPUB. 2005 English 13438832 10.1186/BF03351853 Earth, Planets and Space 57 Springer Berlin 743-753 Disaster Prevention Research Institute, Kyoto University, Kyoto 611-0011, Japan; Institute for Geothermal Sciences, Graduate School of Science, Kyoto University, Kumamoto 869-1404, Japan; Institute of Seismology and Volcanology, Faculty of Sciences, Kyushu University, Nagasaki 855-0843, Japan 8 aeromagnetic survey; cooling; lava flow; magnetic intensity; volcano, Asia; Eastern Hemisphere; Eurasia; Far East; Japan; Kyushu; Nagasaki [Kyushu]; Unzen Volcano; World https://www.scopus.com/inward/record.uri?eid=2-s2.0-26844491999&doi=10.1186%2fBF03351853&partnerID=40&md5=30b161c808706502b238ac7a832836ac cited By 5 A. Okubo Y. Tanaka M. Utsugi N. Kitada H. Shimizu T. Matsushima article Brooks2005235 Results from the first high-resolution, single-channel seismic-reflection survey of tropical Lake Bosumtwi, Ghana, and sedimentological data from a 14C-dated sediment piston core were used to revise and extend the basin's late-Quaternary lake level history. We report four seismic sequence boundaries and an exposure surface from a sediment core, which are interpreted as erosional surfaces formed at times of drastic low lake level. The youngest erosional surface occurs as much as 31 m below present lake level (bpll) and up to 0.7 m below the present sediment-water interface. This most recent unconformity observed in the seismic data is interpreted to be coeval with the basin-wide late-Holocene dry period between 0.5 and 1 cal ky BP (calendar years before present). Another exposure surface observed in a sediment core is based on an abrupt contact separating low density, wet, clay rich sediments from underlying high density, compact, silt-rich and rootlet-rich sediments, and is interpreted to have developed prior to 16.8 cal ky BP when the lake was ∼60 m bpll. Three older, erosional surfaces occur at depths of ∼92±3, 102±3, and 107±4 m bpll, suggesting numerous lowstands in Lake Bosumtwi during the late-Pleistocene. By extrapolation of average sedimentation rates (0.41 m/ky) from the upper ∼10.5 m of sediment, we estimate the ages of these older lowstands to be ∼65, ∼86, ∼108 cal ky BP. The lowstands of Lake Bosumtwi evidenced from the seismic and sediment core data are interpreted as a response to increased aridity in this part of the equatorial tropics and may correlate to other observed continent-wide shifts in African climate over the past 100 ky, and possibly to rapid climatic shifts observed at high latitudes. Determining the precise timing of these lowstands will ultimately reveal much about the drought dynamics of tropical and subtropical Africa. © 2004 Elsevier B.V. All rights reserved. Article 2005 English 00310182 10.1016/j.palaeo.2004.10.005 Palaeogeography, Palaeoclimatology, Palaeoecology 216 Elsevier B.V. 235 – 249 3-4 Africa; Ashanti; Eastern Hemisphere; Ghana; Lake Bosumtwi; Sub-Saharan Africa; West Africa; World; lake level; lowstand; Quaternary; seismic survey https://www.scopus.com/inward/record.uri?eid=2-s2.0-11844278535&doi=10.1016%2fj.palaeo.2004.10.005&partnerID=40&md5=a7e39859c8c7c70baebac4d016b7b68c Cited by: 29 Keely Brooks Christopher A. Scholz John W. King John Peck Jonathan T. Overpeck James M. Russell Philip Y.O. Amoako article Adatte200537 The late Maastrichtian to early Danian at Mishor Rotem, Israel, was examined based on geochemistry, bulk rock and clay mineralogies, biostratigraphy and lithology. This section contains four red clay layers of suspect impact or volcanic origin interbedded in chalk and marly chalks. PGE anomalies indicate that only the K/T boundary red layer has an Ir dominated PGE anomaly indicative of an impact source. The late Maastrichtian red clays have Pd dominated PGE anomalies which coincide with increased trace elements of terrigenous and volcanogenic origins. Deccan or Syrian-Turkey arc volcanism is the likely source of volcanism in these clay layers. Glauconite, goethite and translucent amber spherules are present in the clay layers, but the Si-rich spherules reported by Rosenfeld et al. [1989] could not be confirmed. The absence of Cheto smectite indicates that no altered impact glass has been present. The red layers represent condensed sedimentation on topographic highs during sea level highstands. In the Negev area, during the late Maastrichtian, the climate ranged from seasonally wet to more arid conditions during zones CF3 and CF2, with more humid wet conditions in the latest Maastrichtian zone CF1 and in the early Danian, probably linked to greenhouse conditions. Planktic foraminifera experienced relatively high stress conditions during this time as indicated by the low species richness and low abundance of globotruncanids. Times of intensified stress are indicated by the disaster opportunist Guembelitria blooms, which can be correlated to central Egypt and also to Indian Ocean localities associated with mantle plume volcanism. Marine plankton thus support the mineralogical and geochemical observations of volcanic influx and reveal the detrimental biotic effects of intense volcanism. 2005 10.2113/176.1.37 Bulletin de la Societe Geologique de France 176 37-55 Geological Institut, University of Neuchatel, CH-2007 Neuchatel, Switzerland; Department of Geosciences, Princeton University, Princeton, NJ 08544, United States; Institut of Mineralogy/Geochemistry, University of Karlsruhe, 76128 Karlsruhe, Germany; Geological Institut, University of Karlsruhe, P.O. Box 6980, 76128 Karlsruhe, Germany; Dept. Geol./Environmental Sciences, Ben Gurion University of the Negev, P.O. Box 653, Beer Sheva 84105, Israel 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-15044362467&doi=10.2113%2f176.1.37&partnerID=40&md5=6d2c0c32c2c351cfdba71ca777a2efe1 cited By 22 T. Adatte G. Keller D. Stüben M. Harting U. Kramar W. Stinnesbeck S. Abramovich C. Benjamini article Sakai2005105 Sedimentary cores BDP 96 and 98 and VER 96-2 St. 3 from Academician Ridge in Lake Baikal were investigated to investigate the effect of climatic fluctuations on rock weathering and clay formation in the Baikal drainage basin. Illite, smectite, vermiculite, and kaolinite were identified as the major clay minerals in the sediments by X-ray diffraction analysis. Biotite in gravels in alluvial soils of the Baikal drainage area weathers through illite to vermiculite, smectite, and finally to kaolinite. To investigate the relationship between weathering and climate, we measured the clay content and the concentration of biogenic silica in the sediments. High surface productivity (increased biogenic silica) and high chemical weathering (decreased clay content) occurred simultaneously, showing that crustal weathering and soil formation were enhanced under warm climatic conditions. Clay formation was enhanced in the watershed from the Late Miocene to the Middle Pliocene, and mechanical weathering of rocks increased during glacial intervals after the climate began to cool in Late Pliocene time. This change in the weathering mode in the watershed reduced the nutrient flux and aquatic productivity of Lake Baikal. Article 2005 English 09212728 10.1007/s10933-004-1839-5 Journal of Paleolimnology 33 105 – 121 1 Eastern Hemisphere; Eurasia; Lake Baikal; Russian Federation; World; biogenic deposit; clay mineral; climate change; Miocene; paleolimnology; sediment core; weathering https://www.scopus.com/inward/record.uri?eid=2-s2.0-12544254093&doi=10.1007%2fs10933-004-1839-5&partnerID=40&md5=e6bceda0fdb3a7f78fe6f1ba34f27a96 Cited by: 15 Takayuki Sakai Koji Minoura Mitsuyuki Soma Yukinori Tani Atsushi Tanaka Fumiko Nara Nobuyasu Itoh Takayoshi Kawai article Cohen200542 The San Andreas Fault Observatory at Depth (SAFOD) project to reveal various mysteries associated with an earthquake is discussed. By drilling directly into the fault, the researchers will be able to understand the causes of earthquakes. The results from SAFOD can help to refine the way scientists model earthquakes, and could even help determine the effective ways of predicting a quake's location, timing and size. All the activity is aimed at helping geophysicists understand the setting in which earthquakes develop and the factors that control them. 2005 English 02624079 New Scientist 185 42-45 2485 Cracks; Data acquisition; Global positioning system; Imaging techniques; Methane; Observatories; Oil well drilling; Project management; Seismic waves; Seismology; Tectonics, San Andreas Fault Observatory at Depth (SAFOD) project; Stanford University, California; US Geological Survey; US National Resource Council, Earthquakes https://www.scopus.com/inward/record.uri?eid=2-s2.0-13444271805&partnerID=40&md5=b8250b97a60e4530a64fd0f94ff5bce2 cited By 0 P. Cohen article Wilson2005749 Grain size reduction and gouge formation are found to be ubiquitous in brittle faults at all scales, and most slip along mature faults is observed to have been localized within gouge zones. This fine-grain gouge is thought to control earthquake instability, and thus understanding its properties is central to an understanding of the earthquake process. Here we show that gouge from the San Andreas fault, California, with ∼160 km slip, and the rupture zone of a recent earthquake in a South African mine with only ∼0.4 m slip, display similar characteristics, in that ultrafine grains approach the nanometre scale, gouge surface areas approach 80 m2g-1, and grain size distribution is nonfractal. These observations challenge the common perception that gouge texture is fractal and that gouge surface energy is a negligible contributor to the earthquake energy budget. We propose that the observed fine-grain gouge is not related to quasi-static cumulative slip, but is instead formed by dynamic rock pulverization during the propagation of a single earthquake. 2005 English 00280836 10.1038/nature03433 Nature 434 749-752 School of Geology and Geophysics, University of Oklahoma, Norman, OK 73019, United States; Department of Geological Sciences, University of Nevada, Reno, NV 89557, United States 7034 Comminution; Earthquakes; Fractals; Grain size and shape; Rocks, Earthquake instability; Energetics; Fine-grain gouge; Gouge formation, Particle size analysis, earthquake; particle size, article; earthquake; energy consumption; energy transfer; mining; particle size; priority journal; rock; surface property https://www.scopus.com/inward/record.uri?eid=2-s2.0-17644372729&doi=10.1038%2fnature03433&partnerID=40&md5=c40ab10403bf9473b969399d26366d2c cited By 239 B. Wilson T. Dewers Z. Reches J. Brune article Wilson2005749 Grain size reduction and gouge formation are found to be ubiquitous in brittle faults at all scales, and most slip along mature faults is observed to have been localized within gouge zones. This fine-grain gouge is thought to control earthquake instability, and thus understanding its properties is central to an understanding of the earthquake process. Here we show that gouge from the San Andreas fault, California, with ∼160 km slip, and the rupture zone of a recent earthquake in a South African mine with only ∼0.4 m slip, display similar characteristics, in that ultrafine grains approach the nanometre scale, gouge surface areas approach 80 m2g-1, and grain size distribution is nonfractal. These observations challenge the common perception that gouge texture is fractal and that gouge surface energy is a negligible contributor to the earthquake energy budget. We propose that the observed fine-grain gouge is not related to quasi-static cumulative slip, but is instead formed by dynamic rock pulverization during the propagation of a single earthquake. 2005 English 00280836 10.1038/nature03433 Nature 434 749-752 School of Geology and Geophysics, University of Oklahoma, Norman, OK 73019, United States; Department of Geological Sciences, University of Nevada, Reno, NV 89557, United States 7034 Comminution; Earthquakes; Fractals; Grain size and shape; Rocks, Earthquake instability; Energetics; Fine-grain gouge; Gouge formation, Particle size analysis, earthquake; particle size, article; earthquake; energy consumption; energy transfer; mining; particle size; priority journal; rock; surface property https://www.scopus.com/inward/record.uri?eid=2-s2.0-17644372729&doi=10.1038%2fnature03433&partnerID=40&md5=c40ab10403bf9473b969399d26366d2c cited By 234 B. Wilson T. Dewers Z. Reches J. Brune article Morin20051 As part of the Hawaii Scientific Drilling Project (HSDP), an exploratory hole was drilled in 1993 to a depth of 1056 meters below sea level (mbsl) and a deeper hole was drilled to 3098 mbsl in 1999. A set of geophysical well logs was obtained in the deeper hole that provides fundamental information regarding the structure and the state of stress that exist within a volcanic shield. The acoustic televiewer generates digital, magnetically oriented images of the borehole wall, and inspection of this log yields a continuous record of fracture orientation with depth and also with age to 540 ka. The data depict a clockwise rotation in fracture strike through the surficial Mauna Loa basalts that settles to a constant heading in the underlying Mauna Kea rocks. This behavior reflects the depositional slope directions of lavas and the locations of volcanic sources relative to the drill site. The deviation log delineates the trajectory of the well bore in three-dimensional space. This path closely follows changes in fracture orientation with depth as the drill bit is generally prodded perpendicular to fracture strike during the drilling process. Stress-induced breakouts observed in the televiewer log identify the orientations ot the maximum and minimum horizontal principal stresses to be north-south and east-west, respectively. This stress state is attributed to the combination of a sharp break in onshore-offshore slope that reduces stress east-west and the emergence of Kilauea that increases stress north-south. Breakouts are extensive and appear over approximately 30% of the open hole. Copyright 2005 by the American Geophysical Union. Article 2005 English 21699313 10.1029/2004JB003410 Journal of Geophysical Research: Solid Earth 110 Blackwell Publishing Ltd 1 – 8 7 Hawaiian Islands; oceanic regions; Pacific islands; Pacific Ocean; World; ocean island basalt; stress field; structural geology; volcanic island https://www.scopus.com/inward/record.uri?eid=2-s2.0-25444439015&doi=10.1029%2f2004JB003410&partnerID=40&md5=c4db4d7da511a43734e3276c31c7b7f6 Cited by: 9; All Open Access, Bronze Open Access, Green Open Access Roger H. Morin Roy H. Wilkens article Zhang2005189 Five kinds of UHP metamorphic rocks, including eclogite, orthogneiss, paragneiss, schist and quartzite are exposed in the Qinglongshan roadcut, southern Sulu orogenic belt of eastern central China. They comprise metamorphic supracrustal rocks with bimodal volcanic characteristics and continental affinity, and granitic intrusive associations. The preservation of coesite inclusions and/or its pseudomorphs in eclogite and other rocks indicate that they have been subjected to in-situ UHP metamorphism. Four stages of metamorphism were recognized by combining petrographic observations and compositions of minerals from various UHP rocks. Prograde epidote-amphibolite facies, UHP coesite-eclogite facies, post UHP quartz-eclogite facies, and retrograde amphibolite facies assemblages delineate an inferred P-T path with a clockwise trajectory and a retrograde event characterized by the coupling of decompression with a temperature decrease. Garnet porphyroblasts in UHP eclogites display a complex growth zoning and mineral distribution, and record a crucial segment of the prograde and retrograde metamorphic evolution. The preservation of growth zoning in eclogitic and gneissic garnets suggests that the UHP rocks had a short residence time before retrograde metamorphism and a very high uplift rate in order to preserve the prograde growth zoning. © 2004 Elsevier B.V. All rights reserved. Article 2005 English 00244937 10.1016/j.lithos.2004.10.002 Lithos 81 189 – 207 1-4 Asia; China; Donghai; Eastern Hemisphere; Eurasia; Far East; Jiangsu; Sulu Belt; World; metamorphism; petrogenesis; petrology; ultrahigh pressure metamorphism https://www.scopus.com/inward/record.uri?eid=2-s2.0-15844365132&doi=10.1016%2fj.lithos.2004.10.002&partnerID=40&md5=098f6bb4c481c7bc42e1996dba91561e Cited by: 82 Zeming Zhang Yilin Xiao Fulai Liu J.G. Liou Jochen Hoefs article Zurcher2005223 Carbon, oxygen, and hydrogen isotope results from carbonate and silicate fractions of altered core samples from the Yaxcopoil-1 borehole drilled into the 65 Ma Chicxulub impact crater provide constraints on the physico-chemical parameters of the hydrothermal solutions, and their likely origin. Yaxcopoil-1 impactites were initially permeated with calcite and halite at ambient temperature. This was followed by thermal metamorphism (diopside after igneous augite) and widespread Na-K metasomatism (feldspar after igneous plagioclase), which were overprinted by abundant lower-temperature clay and calcite. Silicate fraction isotopic values have δ 18O SMOW values between 10 and 23% indicating important isotopic exchange between impact melt (∼8%) and Cretaceous limestone (∼26%). Heavier δ 18 O values occur over depth intervals with intense feldspar alteration (813-833 m and 864-872 m). The δD SMOW values (-34 to -54%) are chiefl y infl uenced by smectite abundance and roughly mirror δ 18 O values. Carbonate fraction δ 18 O SMOW values (22-30%) are controlled by calcite contents, and several exceed the limestone signature. Most δ0.13C PDB (-1 to +2%) values also cluster around that of local limestone, but a number are signifi cantly lighter (down to -7%). Isotopic and fluid inclusion results indicate hydrothermal fluid temperatures between 270 and 100 °C, high salinities (∼20%), and minor kerogen contents. These data are compatible with mineralogical constraints, which further support an increase in oxidation state with decreasing temperature. Isotopic data point to a saline CO 2 -bearing fluid mixed with small amounts of reduced carbon, and decarbonation and infi ltration processes. Combined results are most consistent with a basinal oilfi eld saline brine that was driven by impact-induced heat. © 2005 Geological Society of America. 2005 10.1130/0-8137-2384-1.223 Special Paper of the Geological Society of America 384 223-238 Lunar and Planetary Laboratory, University of Arizona, 1629 E. University Boulevard, Tucson, AZ 85721, United States; Department of Geosciences, University of Arizona, 1040 E. Fourth Street, Tucson, AZ 85721, United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-36448978092&doi=10.1130%2f0-8137-2384-1.223&partnerID=40&md5=aa5bf0bc813dd50f0a919a060b37bd79 cited By 12 L. Zurcher D.A. Kring M.D. Barton D. Dettman M. Rollog conference Anderson2005 Gas hydrates (naturally occurring ice-like combinations of gas and water) have the potential to provide vast amounts of natural gas from the world's oceans and polar regions. However, producing gas economically from hydrates entails major technical challenges. Proposed recovery methods such as dissociating or melting gas hydrates by heating or depressurization are currently being tested. One such test was conducted recently in northern Canada by the partners in the Mallik 2002 Gas Hydrate Production Research Well Program. This paper describes how resistivity logs were used to determine the size of the annular region of gas hydrate dissociation that occurred around the wellbore during the thermal test in the Mallik 5L-38 well. An openhole logging suite, run prior to the thermal test, included array induction, array laterolog, nuclear magnetic resonance and 1.1-GHz electromagnetic propagation logs. The reservoir saturation tool was run both before and after the thermal test to monitor formation changes. A cased hole formation resistivity log was run after the test. Baseline resistivity values in each formation layer (Rt) were established from the deep laterolog data. The resistivity in the region of gas hydrate dissociation near the wellbore (Rxo) was determined from electromagnetic propagation and reservoir saturation tool measurements. The radius of hydrate dissociation as a function of depth was then determined by means of iterative forward modeling of cased hole formation resistivity tool response. Pretest computer simulations had predicted that dissociation would take place at a constant radius over the 13-ft test interval. However, the post-test resistivity modeling showed that this was not the case. The resistivity-derived dissociation radius was greatest near the outlet of the pipe that circulated hot water in the wellbore, where the highest temperatures were recorded. The radius was smallest near the center of the test interval, where a conglomerate section with low values of porosity and permeability inhibited dissociation. The free gas volume calculated from the resistivity-derived dissociation radii yielded a value within 20% of surface gauge measurements. These results show that the inversion of resistivity measurements holds promise for use in future gas hydrate monitoring. © 2005, held jointly by the Society of Petrophysicists and Well Log Analysts (SPWLA) and the submitting authors. 2005 English SPWLA 46th Annual Logging Symposium 2005 Society of Petrophysicists and Well-Log Analysts (SPWLA) Schlumberger, United States; U.S. Geological Survey, United States Boreholes; Density measurement (specific gravity); Dissociation; Electric logging; Electromagnetic logging; Gages; Gases; Hydration; Iterative methods; Nuclear magnetic logging; Oil field equipment; Radioactivity logging; Software testing; Thermal logging, Cased hole formation resistivity tools; Cased-hole formation resistivities; Electromagnetic propagation; Gas-hydrate production; Hydrate dissociation; Resistivity measurement; Resistivity modeling; Technical challenges, Gas hydrates https://www.scopus.com/inward/record.uri?eid=2-s2.0-33645153787&partnerID=40&md5=7ca15bc55778ade324006759b67ffb03 cited By 1 B.I. Anderson T.S. Collett R.E. Lewis I. Dubourg article Kinsland2005141 Shuttle Radar Topography Mission (SRTM) data over the Chicxulub impact crater are imaged and compared to previously available topography data. While the two data sets contain different biases related to variations in terrain and vegetation cover, the correspondence of the two sets supports earlier interpretations that the complex structure of the buried crater is expressed in the topography of the northwestern Yucatán Peninsula, México. © 2005 Geological Society of America. 2005 10.1130/0-8137-2384-1.141 Special Paper of the Geological Society of America 384 141-146 Energy Institute, University of Louisiana at Lafayette, Lafayette, LA 70504, United States; Geo Eco Arc Research, 16305 St. Mary's Church Road, Aquasco, MD 20608, United States; Instituto Mexicano del Petróleo, Eje Central Lazaro Cardenas 152, Mexico D.F. 07730, Mexico; Department of Geophysics, University of Witwatersrand, Johannesburg 2050, South Africa; Cowan Geodata Services-Consulting Geophysicists, 12 Edna Road, Dalkeith, WA 6009, Australia; SRTM Project Scientist, Jet Propulsion Laboratory, Pasadena, CA 91109, United States; Regional Application Center, University of Louisiana at Lafayette, Lafayette, LA 70504, United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-73949086112&doi=10.1130%2f0-8137-2384-1.141&partnerID=40&md5=ac108c9f1b0a6565f0999c08a3b7a4df cited By 5 G.L. Kinsland K.O. Pope M.H. Cardador G.R.J. Cooper D.R. Cowan M. Kobrick G. Sanchez article Vahle2005110 We applied the field dependence parameter χHd (%) = [(k300A/m-k30A/m)/k300A/m] × 100 given by de Wall for the subaerial and submarine basalts drilled by the 3109 m deep HSDP-2 borehole on Hawaii in order to verify the hypothesis that mainly composition controls the field dependence of AC susceptibility in titanomagnetite of natural occurrences. When we used this parameter, our data showed a significant scattering compared to data presented in earlier studies. In addition to composition, the effect of measurement temperature, grain size and anisotropy on the field dependent susceptibility were examined and found to be critical. The impact of grain size is weaker than the other effects. It cannot be totally excluded that the observed effects arise indirectly through an overlap of the other effects for the investigated basalts. The most important factor for the variation of field dependence is the degree of oxidation, causing a modification of the titanomagnetite composition or formation of titanomaghemite, and the mixing of Ti-rich with Ti-poor titanomagnetites, which strongly reduces the χHd parameter. Field dependence is not only related to titanomagnetite composition, especially for intermediate titanomagnetites with TCs between 100 and 300 °C. Temperature dependent susceptibility measurements at different field amplitudes for these intermediate types showed at constant geometry of the k(T) curve great differences in susceptibility, resulting in significant changes of the field dependence parameter over the temperature interval from - 100 to 260 °C. herefore variations of the ambient measurement temperatures are able to influence the field dependence. The second important effect is the degree of particle shape and alignment, which controls the field dependence in different orientations especially for the intermediate titanomagnetite, which is intensively intergrown with elongated hemoilmenite grains. As a consequence, samples with higher degrees of anisotropy exhibit differences of the field dependence parameter if measured parallel to kmax or kmin axis. Therefore, in addition to compositional effects and the temperature dependence, the magnetic fabric has to be considered for the interpretation of field dependent susceptibility measurements. The influence of intrinsic (Ti-content, magnetocrystalline anisotropy), and extrinsic (shape and alignment of grains) factors for the interpretation of the degree of anisotropy has to be kept in mind when interpreting AMS data in terms of strain rates experienced by moving lava during emplacement. © 2005 Elsevier B.V. All rights reserved. Article 2005 English 0012821X 10.1016/j.epsl.2005.07.010 Earth and Planetary Science Letters 238 110 – 129 1-2 Hawaii [(ISL) Hawaiian Islands]; Hawaii [United States]; Hawaiian Islands; North America; oceanic regions; Pacific islands; Pacific Ocean; United States; Western Hemisphere; World; Basalt; Composition effects; Grain size and shape; Magnetic susceptibility; Magnetite; Mineralogy; Oxidation; Field dependence; Magnetic fabrics; Magnetic mineralogy; Titanomagnetite; basalt; magnetic field; magnetic susceptibility; titanomagnetite; Geochemistry https://www.scopus.com/inward/record.uri?eid=2-s2.0-26944501970&doi=10.1016%2fj.epsl.2005.07.010&partnerID=40&md5=18996f05ff3a683ac3f3c8a1f8c76357 Cited by: 21 Carsten Vahle article Yasuda200588 It is estimated that significant amount of methane hydrate resources are deposited offshore Japan and the Research Consortium of Methane Hydrate Resources in Japan (MH21 Research Consortium) was established to undertake the "Japan's Methane Hydrate Exploitation Program" which was prepared by the Ministry of Economy, Trade and Industry and announced in 2001. MH21 Research Consortium planned onshore tests of gas production from gas hydrate reservoir and the Mallik 2002 Gas Hydrate Production Research Well Program was formed in which eight bodies participated from five countries. The test site was located in onshore Mackenzie delta of Northwestern Canada. The swamp feature of the site restricted the whole test operation only in winter when frozen firm ground and transportation road are formed. From December 25th 2001 to March 14th 2002, one gas production test well and two observation wells were drilled. Pressure draw down test using MDT and a hot water circulation test were tried , and the latter test yielded 468m3 dissociated gas from the hydrate reservoir, which was the first success of gas production from naturally deposited gas hydrate reservoir. In December 2003, Mallik International Symposium was held in Chiba, Japan with more than 200 researchers' participation from thirteen countries. The success of the Mallik Program was officially announced for the first time at the Symposium. 2005 Japanese 09168753 Nihon Enerugi Gakkaishi/Journal of the Japan Institute of Energy 84 88-92 Japan Oil, Gas and Metals National Corporation, 1-2-2 Hamada, Mihama, Chiba 261-0025, Japan 2 Economics; Methane; Motor transportation; Natural gas; Natural gas well drilling; Technical presentations, Gas hydrate reservoir; Gas production; Mallik; MH21, Gas hydrates https://www.scopus.com/inward/record.uri?eid=2-s2.0-19944404248&partnerID=40&md5=fa296da8ab63a1e0dee20e185b950d8f cited By 0 M. Yasuda article Fridleifsson2005269 Article 2005 10.1016/j.geothermics.2004.11.004 Geothermics 34 269 – 285 3 https://www.scopus.com/inward/record.uri?eid=2-s2.0-19144362878&doi=10.1016%2fj.geothermics.2004.11.004&partnerID=40&md5=262a25b40145097c5d59ff34446b8eaa Cited by: 126 Gudmundur Ó. Fridleifsson Wilfred A. Elders article Koeberl200523 The 10.5 -km-diameter, 1.07-Ma Bosumtwi impact crater was the subject of a multi-disciplinary and international drilling effort of the International Continental Scientific Drilling Program (ICDP) from July to October 2004. Sixteen different holes were drilled at six locations within the lake, to a maximum depth of 540 m. A total of about 2.2 km of core material was obtained. Despite some technical and logistical challenges, the project has been very successful and it is anticipated that the first scientific results will be available in late 2005. © 2005 Copernicus GmbH. Article 2005 English 18168957 10.2204/iodp.sd.1.04.2005 Scientific Drilling 1 Copernicus GmbH 23 – 27 Coremaking; Lakes; Continental scientific drillings; Core material; Drilling projects; Impact craters; Scientific results; Infill drilling https://www.scopus.com/inward/record.uri?eid=2-s2.0-84871521923&doi=10.2204%2fiodp.sd.1.04.2005&partnerID=40&md5=308aa0fdc62e3243bdbf725b0795463a Cited by: 10; All Open Access, Gold Open Access, Green Open Access Christian Koeberl John Peck John King Bernd Milkereit Jonathan Overpeck Christopher Scholz article melles2005expedition 2005 Berichte zur Polar-und Meeresforschung (Reports on Polar and Marine Research) 509 Alfred Wegener Institute for Polar and Marine Research Martin Melles P Minyuk J Brigham-Grette article Ren2005837 The Hawaiian-Emperor volcanic island and seamount chain is usually attributed to a hot mantle plume, located beneath the Pacific lithosphere, that delivers material sourced from deep in the mantle to the surface. The shield volcanoes of the Hawaiian islands are distributed in two curvilinear, parallel trends (termed 'Kea' and 'Loa'), whose rocks are characterized by general geochemical differences. This has led to the proposition that Hawaiian volcanoes sample compositionally distinct, concentrically zoned, regions of the underlying mantle plume. Melt inclusions, or samples of local magma 'frozen' in olivine phenocrysts during crystallization, may record complexities of mantle sources, thereby providing better insight into the chemical structure of plumes. Here we report the discovery of both Kea- and Loa-like major and trace element compositions in olivine-hosted melt inclusions in individual, shield-stage Hawaiian volcanoes-even within single rock samples. We infer from these data that one mantle source component may dominate a single lava flow, but that the two mantle source components are consistently represented to some extent in all lavas, regardless of the specific geographic location of the volcano. We therefore suggest that the Hawaiian mantle plume is unlikely to be compositionally concentrically zoned. Instead, the observed chemical variation is probably controlled by the thermal structure of the plume. 2005 English 00280836 10.1038/nature03907 Nature 436 837-840 Department of Earth and Planetary Sciences, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, 152-8551, Japan; Institute for Frontier Research on Earth Evolution, Japan Agency for Marine-Earth Science and Technology, Natsushima-cho 2-15, Yokosuka, Kanagawa 237-0061, Japan; School of Ocean and Earth Science and Technology, University of Hawaii, POST 615A, 1680 East-West Road, Honolulu, HI 96822, United States 7052 Crystallization; Geochemistry; Olivine; Thermal plumes, Lithospheres; Mantle plumes; Olivine phenocryst; Volcanic islands, Volcanic rocks, trace element, chemical composition; mantle chemistry; mantle plume; melt inclusion; seamount, article; chemical composition; geochemistry; geography; geology; heat; island (geological); lava; lithosphere; mantle plume; priority journal; rock; thermal structure; United States; volcano, Hawaiian Islands; oceanic regions; Pacific islands; Pacific Ocean; World https://www.scopus.com/inward/record.uri?eid=2-s2.0-23844542458&doi=10.1038%2fnature03907&partnerID=40&md5=4371d1afabb8791da380bc004c4784d3 cited By 104 Z.-Y. Ren S. Ingle E. Takahashi N. Hirano T. Hirata article Sharp2005 The Hawaii Scientific Drilling Project, phase 2 (HSDP-2), recovered core from a ∼3.1-km-thick section through the eastern flanks of Mauna Loa and Mauna Kea volcanoes. We report results of 40Ar/39Ar incremental heating by broad-beam infrared laser of 16 basaltic groundmass samples and 1 plagioclase separate, mostly from K-poor tholeiites. The tholeiites generally have mean radiogenic 40Ar enrichments of 1-3%, and some contain excess 40Ar; however, isochron ages of glass-poor samples preserve stratigraphic order in all cases. A 246-m-thick sequence of Mauna Loa tholeiitic lavas yields an isochron age of 122 ± 86 kyr (all errors 2<r) at its base. Beneath the Mauna Loa overlap sequence lie Mauna Kea's postshield and shield sequences. A postshield alkalic lava yields an age of 236 ± 16 kyr, in agreement with an age of 240 ± 14 kyr for a geochemically correlative flow in the nearby HSDP-1 core hole, where more complete dating of the postshield sequence shows it to have accumulated at 0.9 ± 0.4 m/kyr, from about 330 to <200 ka. Mauna Kea's shield consists of subaerial tholeiitic flows to a depth of 1079 m below sea level, then shallow submarine flows, hyaloclastites, pillow lavas, and minor intrusions to core bottom at 3098 m. Most subaerial tholeiitic flows fail to form isochrons; however, a sample at 984 m yields an age of 370 ± 180 kyr, consistent with ages from similar levels in HSDP-1. Submarine tholeiites including shallow marine vitrophyres, clasts from hyaloclastites, and pillow lavas were analyzed; however, only pillow lava cores from 2243, 2614, and 2789 m yield reliable ages of 482 ± 67, 560 ± 150, and 683 ± 82 kyr, respectively. A linear fit to ages for shield samples defines a mean accumulation rate of 8.6 ± 3.1 m/kyr and extrapolates to ∼635 kyr at core bottom. Alternatively, a model relating Mauna Kea's growth to transport across the Hawaiian hot spot that predicts downward accelerating accumulation rates that reach ∼20 m/kyr at core bottom (DePaolo and Stolper, 1996) is also consistent with all reliable ages except the deepest. Copyright 2005 by the American Geophysical Union. Article 2005 English 15252027 10.1029/2004GC000846 Geochemistry, Geophysics, Geosystems 6 4 https://www.scopus.com/inward/record.uri?eid=2-s2.0-22444447594&doi=10.1029%2f2004GC000846&partnerID=40&md5=51e8e430a553cfe0774c59d05065eb52 Cited by: 114; All Open Access, Bronze Open Access Warren D. Sharp Paul R. Renne article Ebel2005293 Formation of the giant Chicxulub crater off Mexico's Yucatan Peninsula coincided with deposition of the global Ir-rich Cretaceous-Tertiary (K-T) stratigraphic boundary layer ca. 65 Ma. The boundary is marked most sharply by abundant spherules containing un-altered grains of magnesioferrite spinel. Here we predict for the first time the sequential condensation of solids and liquids from the plume of vaporized rock expected from oblique K-T impacts. We predict highly oxidizing plumes that condense silicate liquid droplets bearing spinel grains whose compositions closely match those marking the actual boundary. Systematic global variations in spinel composition are consistent with higher condensation temperatures for spinels found at Atlantic and European sites than for those in the Pacific. © 2005 Geological Society of America. 2005 10.1130/G21136.1 Geology 33 293-296 Dept. of Earth/Planetary Sciences, American Museum of Natural History, 79th Street at Central Park West, New York, NY 10024-5192, United States; Dept. of the Geophysical Sciences, Enrico Fermi Institute, University of Chicago, Chicago, IL 60637, United States 4 https://www.scopus.com/inward/record.uri?eid=2-s2.0-17144377156&doi=10.1130%2fG21136.1&partnerID=40&md5=755403fa8d3a339c2c3fc198817947d4 cited By 45 D.S. Ebel L. Grossman article Naumov2005165 Any hypervelocity impact generates a hydrothermal circulation system in resulting craters. Common characteristics of hydrothermal fluids mobilized within impact structures are considered, based on mineralogical and geochemical investigations, to date. There is similarity between the hydrothermal mineral associations in the majority of terrestrial craters; an assemblage of clay minerals-zeolites-calcite-pyrite is predominant. Combining mineralogical, geochemical, fluid inclusion, and stable isotope data, the distinctive characteristics of impact-generated hydrothermal fluids can be distinguished as follows: (i) superficial, meteoric and ground water and, possibly, products of dehydration and degassing of minerals under shock are the sources of hot water solutions; (ii) shocked target rocks are sources of the mineral components of the solutions; (iii) flow of fluids occurs mainly in the liquid state; (iv) high rates of flow are likely (10-4 to 10-3 m s-1); (v) fluids are predominantly aqueous and of low salinity; (vi) fluids are weakly alkaline to near-neutral (pH 6-8) and are supersaturated in silica during the entire hydrothermal process because of the strong predominance of shock-disordered aluminosilicates and fusion glasses in the host rocks; and (vii) variations in the properties of the circulating solutions, as well as the spatial distribution of secondary mineral assemblages are controlled by temperature gradients within the circulation cell and by a progressive cooling of the impact crater. Products of impact-generated hydrothermal processes are similar to the hydrothermal mineralization in volcanic areas, as well as in modern geothermal systems, but impacts are always characterized by a retrograde sequence of alteration minerals. © 2005 Blackwell Publishing Ltd. 2005 10.1111/j.1468-8123.2005.00092.x Geofluids 5 165-184 Karpinsky All-Russia Geological Research Institute (VSEGEI), 199106 Sredny pr. 74, St. Petersburg, Russian Federation 3 https://www.scopus.com/inward/record.uri?eid=2-s2.0-22744445294&doi=10.1111%2fj.1468-8123.2005.00092.x&partnerID=40&md5=477bfb8c4fff5946d31415ab743bf354 cited By 91 M.V. Naumov conference Taylor2005174 The San Andreas Fault (SAF) is the surface expression of a major plate tectonic boundary of the Pacific Plate. While widely known as the San Andreas Fault, it is probably better thought of as an extensive fault system that represents a major transform boundary between the North American and Pacific Plates. The sequence of M=6 earthquakes along the fault near Parkfield, California has stimulated an intense research effort into the seismogenic processes of brittle deformation in the upper crust along the San Andreas Fault. Part of this research effort has led to large network of surface instrumentation in the vicinity of Parkfield including seismometers, strain meters, and a variety of other geologic monitoring equipment. Recently, further instrumentation efforts have focused primarily on subsurface monitoring of seismogenic processes as part of the San Andreas Fault Observatory at Depth (SAFOD) project. In this paper, we review our recent research conducted to determine the local subsurface structure at the SAFOD site. We then present our structural interpretation of vertical seismic profiling data collected during recent crustal profiling studies. We conclude that the observed shear wave anisotropy in our VSP data is the result of aligned fracture sets which are most likely R shears. R shears are one component of conjugate Riedel fracturing associated with shear zone tectonic deformation. © Society of Exploration Geophysicists - 75th SEG International Exposition and Annual Meeting, SEG 2005. All rights reserved. 2005 English 9781604236101 10.1190/1.2144291 Society of Exploration Geophysicists - 75th SEG International Exposition and Annual Meeting, SEG 2005 Society of Exploration Geophysicists 174-177 Duke University, United States; Schlumberger-Doll Research, United States Anisotropy; Deformation; Observatories; Plates (structural components); Seismic prospecting; Seismology; Shear flow; Shear waves; Strike-slip faults, Monitoring equipment; San andreas fault observatory at depth projects; Shear-wave anisotropy; Structural interpretation; Subsurface monitoring; Subsurface structures; Tectonic deformations; Vertical seismic profiling, Transform faults https://www.scopus.com/inward/record.uri?eid=2-s2.0-84883683463&doi=10.1190%2f1.2144291&partnerID=40&md5=cd9d68a6e0b737fcf430bd01c2aff3b0 cited By 9 S. Taylor P. Malin J.B.U. Haldorsen article Geissler20051 P-SV conversions provide new insights into the lithosphere of the western Eger (Ohře) Rift, a presently active CO2 emanation area, Quaternary volcanic field, and earthquake swarm region in central Europe. Gas and isotope (He and C) mapping of free gas phases in mineral springs and mofettes proved the origin Of CO2-dominated gases from a subcrustal magmatic fluid reservoir. Analyzing teleseismic data from several seismic networks in the western Bohemian Massif the source region of these gases was investigated Moho Ps conversions have 3 to 4.5 s delay. Crustal thicknesses vary between 27 and 38 km; vp/vs ratios vary between 1.63 and 1.81. Beneath the western Eger Rift an approximately 40 km wide Moho updoming up to 27 km exists. Locally observed weak conversions indicate a complex Moho transition zone in this area. A local "6 s phase" possibly originates at a discontinuity in approximately 50 to 60 km depth or may represent multiples from velocity inversions at the base of the upper crust. Moho updoming and the distribution of the "6 s phase" coincide with the CO2 degassing fields and the positions of Quaternary volcanoes at the surface. We hypothesize the release of CO2-dominated fluid/magma from isolated melt reservoirs in the depth range of 60 to 30 km, separation of CO2 from the melt at 29 to 21 km depths, and CO2 transport through the crust. The geophysical indications may point to presently active magmatic underplating beneath the study area, supporting the results of gas geochemical and isotope investigations. This is the first attempt that combines seismic and gas geochemical data for a tectonic model. Our model may be transferable to other continental rift areas worldwide. Copyright 2005 by the American Geophysical Union. Article 2005 English 02787407 10.1029/2004TC001672 Tectonics 24 1 – 23 5 Central Europe; Eurasia; Europe; Ohre River; carbon dioxide; lithospheric structure; seismic velocity; upper mantle https://www.scopus.com/inward/record.uri?eid=2-s2.0-23344445479&doi=10.1029%2f2004TC001672&partnerID=40&md5=85dc499b91d4d419a3f34a186ee050ec Cited by: 99; All Open Access, Bronze Open Access Wolfram H. Geissler Horst Kämpf Rainer Kind Karin Bräuer Klaus Klinge Thomas Plenefisch Josef Horálek Jan Zedník Vladimir Nehybka article nakada2005scientific 2005 Scientific drilling 1 18--22 Setsuya Nakada Kozo Uto Sumio Sakuma John C Eichelberger Hiroshi Shimizu article Dallimore2005 2005 English 00687626 10.4095/220702 Bulletin of the Geological Survey of Canada Energy, Mines and Resources Canada iii-iv Geological Survey of Canada - Pacific, 9860 West Saanich Road, Sidney, BC V8L 4B2, Canada; United States Geological Survey, Denver Federal Centre, Box 25046, Denver, CO 80225, United States; JAPEX Research Center, 1-2-1 Hamada, Mihama-ku, Chiba 2610025, Japan; GeoForschungsZentrum, Telegrafenberg D-14473 Potsdam, Germany; United States Department of Energy, National Energy Technology Laboratory, 3610 Collins Ferry Road, Morgantown, WV 26507, United States; BP Canada Energy Company, Calgary 240-4th Avenue SW, Calgary, Alta. T2P 2H8, Canada; JNOC Technology Research Center, Japan National Oil Corporation, 1-2-2 Hamada, Mihama-ku, Chiba 261-0025, Japan 585 gas hydrate https://www.scopus.com/inward/record.uri?eid=2-s2.0-27744500622&partnerID=40&md5=c4f4b022aabc3644a4d64f3b3521b91b cited By 131 S.R. Dallimore T.S. Collet A.E. Taylor T. Uchida M. Weber A. Chandra T.H. Mroz E.M. Caddel T. Inoue article Uto200513 The subsurface structure and magma ascending mechanism of Unzen Volcano was investigated by Unzen Scientific Drilling project (USDP) not only by scientific drillings but also related by geophysical and geochemical studies. A hole was drilled to reach the conduit of the Heisei eruption inorder to clarify the ascending and degassing process of magma and to understand the mechanism of an eruption. There was a conduit zone near the area right under Mt.Fugen at around the sea level, where old and new conduits including the Heisei conduit were concentrated within approximately 500 meters. The temperature in the conduit zone was approximately 200°C, lower than expected before the drilling resulted from quick cooling due to hydrothermal activities. 2005 English 1346602X AIST Today (International Edition) 13 Institute of Geology and Geoinformation, Japan 16 https://www.scopus.com/inward/record.uri?eid=2-s2.0-23944450912&partnerID=40&md5=27f47bfbec8a680ae952631be388fa1a cited By 0 K. Uto article HortonJr.2005147 Four new coreholes in the western annular trough of the buried, late Eocene Chesapeake Bay impact structure provide samples of shocked minerals, cataclastic rocks, possible impact melt, mixed sediments, and damaged microfossils. Parautochthonous Cretaceous sediments show an upward increase in collapse, sand fluidization, and mixed sediment injections. These impact-modifi ed sediments are scoured and covered by the upper Eocene Exmore beds, which consist of highly mixed Cretaceous to Eocene sediment clasts and minor crystalline-rock clasts in a muddy quartz-glauconite sand matrix. The Exmore beds are interpreted as seawater-resurge debris flows. Shocked quartz is found as sparse grains and in rock fragments at all four sites in the Exmore, where these fallback remnants are mixed into the resurge deposit. Crystalline-rock clasts that exhibit shocked quartz or cataclastic fabrics include felsites, granitoids, and other plutonic rocks. Felsite from a monomict cataclasite boulder has a sensitive high-resolution ion microprobe U-Pb zircon age of 613 ± 4 Ma. Leucogranite from a polymict cataclasite boulder has a similar Neoproterozoic age based on muscovite 40 Ar/ 39 Ar data. Potassium-feldspar 40 Ar/ 39 Ar ages from this leucogranite show cooling through closure (∼150 °C) at ca. 261 Ma without discernible impact heating. Spherulitic felsite is under investigation as a possible impact melt. Types of crystalline clasts, and exotic sediment clasts and grains, in the Exmore vary according to location, which suggests different provenances across the structure. Fractured calcareous nannofossils and fused, bubbled, and curled dinofl agellate cysts coexist with shocked quartz in the Exmore, and this damage may record conditions of heat, pressure, and abrasion due to impact in a shallow-marine environment. © 2005 Geological Society of America. 2005 English 00721077 10.1130/0-8137-2384-1.147 Special Paper of the Geological Society of America 384 Geological Society of America 147-170 U.S. Geological Survey, MS 926A, 12201 Sunrise Valley Drive, Reston, VA 20192, United States; U.S. Geological Survey, MS 963, Denver Federal Center, Denver, CO 80225, United States; Department of Geology, College of William and Mary, 3012 East Whittaker Close, Williamsburg, VA 23285, United States Argon; Binary alloys; Crystalline materials; Crystalline rocks; Debris; Feldspar; Fluidization; Geochronology; Lead alloys; Mica; Quartz; Rocks; Sediments; Silicate minerals; Structural geology; Zircon, Cataclastic; Chesapeake; Crater; Dinofl agellate; Ejecta; Impact; Nannofossil; Resurge; Shock; SHRIMP, Meteor impacts, abrasion; cataclasite; Cretaceous; ejecta; Eocene; fluidization; impact structure; ion microprobe; leucogranite; melt; muscovite; quartz; research; sand; zircon, Chesapeake Bay; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-73949090062&doi=10.1130%2f0-8137-2384-1.147&partnerID=40&md5=2f04f8852b2373bea591d26d0e62fe07 cited By 38 J.W. Horton Jr. J.N. Aleinikoff M.J. Kunk G.S. Gohn L.E. Edwards J.M. Self-Trail D.S. Powars G.A. Izett article Sherlock20051777 We have re-evaluated the published age information for the Haughton impact structure, which was believed to have formed ∼23 Ma ago during the Miocene age, and report new Ar/Ar laser probe data from shocked basement clasts. This reveals an Eocene age, which is at odds with the published Miocene stratigraphic, apatite fission track and Ar/Ar data; we discuss our new data within this context. We have found that the age of the Haughton impact structure is ∼39 Ma, which has implications for both crater recolonization models and post-impact hydrothermal activity. Future work on the relationship between flora and fauna within the crater, and others at high latitude, may resolve this paradox. © The Meteoritical Society, 2005. 2005 10.1111/j.1945-5100.2005.tb00146.x Meteoritics and Planetary Science 40 1777-1787 Centre for Earth Planetary Space and Astronomical Research (CEPSAR), Department of Earth Sciences, The Open University, Walton Hall, Milton Keynes MK7 6AA, United Kingdom; Department of Geology and Petroleum Geology, College of Physical Sciences, University of Aberdeen, Meston Building, Aberdeen AB24 3UE, United Kingdom; Geotrack International, 37 Melville Road, Brunswick West, Vic. 3055, Australia; Mars Institute, NASA Ames Research Center, MS 245-3, Moffett Field, CA 94035-1000, United States; Canadian Space Agency, 6767 Route de l'Aeroport, Saint-Hubert, Que. J3Y 8Y9, Canada; Centre for Earth Planetary Space and Astronomical Research (CEPSAR), Planetary and Space Sciences Research Institute, The Open University, Walton Hall, Milton Keynes MK7 6AA, United Kingdom 12 https://www.scopus.com/inward/record.uri?eid=2-s2.0-33244493970&doi=10.1111%2fj.1945-5100.2005.tb00146.x&partnerID=40&md5=1adf767a3c9a23a32d72545168e851db cited By 41 S.C. Sherlock S.P. Kelley J. Parnell P. Green P. Lee G.R. Osinski C.S. Cockell article Lin2005 H2 is probably the most important substrate for terrestrial subsurface lithoautotrophic microbial communities. Abiotic H2 generation is an essential component of subsurface ecosystems truly independent of surface photosynthesis. Here we report that H2 concentrations in fracture water collected from deep siliclastic and volcanic rock units in the Witwatersrand Basin, South Africa, ranged up to two molar, a value far greater than observed in shallow aquifers or marine sediments. The high H2 concentrations are consistent with that predicted by radiolytic dissociation of H2O during radioactive decay of U, Th, and K in the host rock and the observed He concentrations. None of the other known H2-generating mechanisms can account for such high H2 abundance either because of the positive free energy imposed by the high H2 concentration or pH or because of the absence of required mineral phases. The radiolytic H 2 is consumed by methanogens and abiotic hydrocarbon synthesis. Our calculations indicate that radiolytic H2 production is a ubiquitous and virtually limitless source of energy for deep crustal chemolithoautotrophic ecosystems. Copyright 2005 by the American Geophysical Union. 2005 English 15252027 10.1029/2004GC000907 Geochemistry, Geophysics, Geosystems 6 Department of Geosciences, Princeton University, Princeton, NJ 08540, United States; Geophysical Laboratory, Carnegie Institution of Washington, 5251 Broad Branch Road, N.W., Washington, DC 20015, United States; Lamont-Doherty Earth Observatory, Columbia University, 61 Route 9W, Palisades, NY 10964, United States; Geo Forschungs Zentrum Potsdam, Telegraphenberg, Haus B, 320, D-14473 Potsdam, Germany; Stable Isotope Laboratory, Department of Geology and Geophysics, University of Toronto, Toronto, 22 Russel Street, Toronto, ON M5S 3D1, Canada; GeoSyntec Consultants, 1 Airport Place, Princeton, NJ 08540, United States; Shaw Group, 4100 Quakerbridge Road, Lawrenceville, NJ 08648, United States; Pacific Northwest National Laboratory, Mailstop P7-50, 902 Battelle Boulevard, Richland, WA 99352, United States; Department of Geosciences, Princeton, NJ 08540, United States 7 https://www.scopus.com/inward/record.uri?eid=2-s2.0-24644521340&doi=10.1029%2f2004GC000907&partnerID=40&md5=48ff3410b2d580a26231893026ab9fc3 cited By 161 L.-H. Lin J. Hall J. Lippmann-Pipke J.A. Ward B.S. Lollar M. DeFlaun R. Rothmel D. Moser T.M. Gihring B. Mislowack T.C. Onstott article Tarasov2005625 Changes in mean temperature of the coldest (Tc) and warmest month (Tw), annual precipitation (Pann) and moisture index (α) were reconstructed from a continuous pollen record from Lake Baikal, Russia. The pollen sequence CON01-603-2 (53°57′N, 108°54′E) was recovered from a 386 m water depth in the Continent Ridge and dated to ca. 130-114.8 ky BP. This time interval covers the complete last interglacial (LI), corresponding to MIS 5e. Results of pollen analysis and pollen-based quantitative biome reconstruction show pronounced changes in the regional vegetation throughout the record. Shrubby tundra covered the area at the beginning of MIS 5e (ca. 130-128 ky), consistent with the end of the Middle Pleistocene glaciation. The late glacial climate was characterised by low winter and summer temperatures (Tc ∼ -38 to -35°C and Tw∼11-13°C) and low annual precipitation (Pann∼300 mm). However, the wide spread of tundra vegetation suggests rather moist environments associated with low temperatures and evaporation (reconstructed α∼1). Tundra was replaced by boreal conifer forest (taiga) by ca. 128 ky BP, suggesting a transition to the interglacial. Taiga-dominant phase lasted until ca. 117.4 ky BP, e.g. about 10 ky. The most favourable climate conditions occurred during the first half of the LI. Pann reached 500 mm soon after 128 ky BP. However, temperature changed more gradually. Maximum values of Tc ∼-20°C and Tw ∼16-17°C are reconstructed from about 126 ky BP. Conditions became gradually colder after ca. 121 ky BP. Tc dropped to ∼ -27°C and T w to ∼15°C by 119.5 ky BP. The reconstructed increase in continentality was accompanied by a decrease in Pann to ∼400-420 mm. However, the climate was still humid enough (α∼0.9) to support growth of boreal evergreen conifers. A sharp turn towards a dry climate is reconstructed after ca. 118 ky BP, causing retreat of forest and spread of cool grass-shrub communities. Cool steppe dominated the vegetation in the area between ca. 117.5 ky and 114.8 ky BP, suggesting the end of the interglacial and transition to the last glacial (MIS 5d). Shift to the new glaciation was characterised by cool and very dry conditions with Tc ∼ -28 to -30°C, Tw ∼14-15°C, Pann ∼250 mm and α∼0.5. © Springer-Verlag 2005. Article 2005 English 14320894 10.1007/s00382-005-0045-0 Climate Dynamics 25 625 – 637 6 Eurasia; Lake Baikal; Russian Federation; Coniferophyta; climate change; Last Interglacial; pollen; reconstruction; vegetation history; vegetation type https://www.scopus.com/inward/record.uri?eid=2-s2.0-27744601428&doi=10.1007%2fs00382-005-0045-0&partnerID=40&md5=acc1f3920e96e7c973973f2a7f038fc3 Cited by: 82 Pavel Tarasov W. Granoszewski E. Bezrukova S. Brewer M. Nita A. Abzaeva H. Oberhänsli article Oberhänsli20051 Conference paper 2005 English 09218181 10.1016/j.gloplacha.2004.11.003 Global and Planetary Change 46 Elsevier B.V. 1 – 7 1-4 SPEC. ISS. paleoclimate https://www.scopus.com/inward/record.uri?eid=2-s2.0-18044362369&doi=10.1016%2fj.gloplacha.2004.11.003&partnerID=40&md5=a1593bcb28c0e12e8b99f368e945793b Cited by: 14; All Open Access, Green Open Access Hedi Oberhänsli Anson W. Mackay article Demske2005255 High-resolution pollen records from Lake Baikal revealed considerable regional differences in the vegetation development and pronounced climate variability during the last glacial-interglacial transition and Holocene. Correlation between cores was successfully based on a chronology constructed from AMS 14C dating of pollen concentrates. Comparison to other radiocarbon-dated pollen sequences from the Baikal region suggests that the chronology presented is very reliable, and thus correlation to other dated events can easily be performed. Pollen indices, which reflect relative changes in major vegetation types and limitations of growing conditions by moisture availability and temperature, demonstrate near-synchronous vegetation changes, which suggest synchronous large-scale climate variation across the Baikal region. Due to the limited influence of human impact in the Lake Baikal region, the pollen data illustrate that, in the continental interior of NE Eurasia Holocene, climate variability was very pronounced. After initial warming and a strong increase in relative moisture (ca. 16 cal ka BP), the Bølling-Allerød-like event was punctuated by three cool and dry events. These events, dated between ca. 15 and 13 cal ka BP, can be compared to coolings as recorded in GISP 2 oxygen isotope records from Greenland ice cores. An expansion of Betula sect. Nanae/Fruticosae, Artemisia and Chenopodiaceae marks the Younger-Dryas (YD)-like cooling event (ca. 12.5-12 cal ka BP). High temperatures and favourable moisture conditions during the first part of Holocene favoured the optimum development of dark coniferous taiga between 11-7.5 cal ka BP in the south and 10-8 cal ka BP in the northeast. A fir and spruce decline in the southern mountains (ca. 9.5-8.5 cal ka BP) can be related to the 8.2 cal ka BP cooling event. The pronounced mid-Holocene cooling event and a transition towards dry conditions (ca. 8-7 cal ka BP) preceded the nearly synchronous regional expansion of pine taiga. Maximum distribution of Scots pine forests marks the Holocene thermal optimum (ca. 6.5-5.7 cal ka BP), which was followed by two subsequent cooling events (ca. 5.5-4.5 cal ka BP) at the Atlantic-Subboreal transition. A subsequent temperature optimum in the southeastern Baikal region ended with pronounced cooling during the Subboreal-Subatlantic transition (ca. 3-2.5 cal ka BP). A late spread of shrub alders may evidence the beginning of the Little Ice Age. © 2004 Elsevier B.V. All rights reserved. Conference paper 2005 English 09218181 10.1016/j.gloplacha.2004.09.020 Global and Planetary Change 46 Elsevier B.V. 255 – 279 1-4 SPEC. ISS. Eastern Hemisphere; Eurasia; Lake Baikal; Russian Federation; World; Abies; Acer pensylvanicum; Alnus; Amaranthaceae; Artemisia; Betula; Betulaceae; Picea; Pinus sylvestris; climate variation; Holocene; late glacial; paleoclimate; palynology; vegetation history https://www.scopus.com/inward/record.uri?eid=2-s2.0-18044369710&doi=10.1016%2fj.gloplacha.2004.09.020&partnerID=40&md5=785d49d9eecb40f784a367b01ef74845 Cited by: 147; All Open Access, Green Open Access Dieter Demske Georg Heumann Wojciech Granoszewski Małgorzata Nita Kazimiera Mamakowa Pavel E. Tarasov Hedi Oberhänsli article Henninges20051 Detailed knowledge about thermal properties of rocks containing gas hydrate is required in order to quantify processes involving gas hydrate formation and decomposition in nature. In the framework of the Mallik 2002 program, three wells penetrating a continental gas hydrate occurrence under permafrost were successfully equipped with permanent fiber-optic distributed temperature sensing cables. Temperature data were collected over a 21-month period after completing the wells. Thermal conductivity profiles were calculated from the geothermal data as well as from a petrophysical model derived from the available logging data and application of mixing law models. Results indicate that thermal conductivity variations are mainly lithologically controlled with a minor influence from hydrate saturation. Average thermal conductivity values of the hydrate-bearing sediments range between 2.35 and 2.77 W m-1 K-1. Maximum gas hydrate saturations can reach up to about 90% at an average porosity of 0.3. Copyright 2005 by the American Geophysical Union. 2005 English 21699313 10.1029/2005JB003734 Journal of Geophysical Research: Solid Earth 110 Blackwell Publishing Ltd 1-11 Section Geothermics, GeoForschungsZentrum Potsdam, D-14473 Potsdam, Germany; Fachgebiet Angewandte Geophysik, Technische Universität Berlin, Ackerstraße 71-76, D-13355 Berlin, Germany 11 gas hydrate; sediment property; thermal conductivity https://www.scopus.com/inward/record.uri?eid=2-s2.0-30144437414&doi=10.1029%2f2005JB003734&partnerID=40&md5=099dd97352bd4c0a3cd0feeb767eee58 cited By 77 J. Henninges E. Huenges H. Burkhardt article Boswell20058 The potential of offshore deposits of methane hydrates as energy resource is discussed. The efforts to develop methods that would make production of methane from hydrate both technologically feasible and economically viable are also presented. Methane hydrate is a very efficient storehouse of energy, and when dissociated, a single cubic foot of solid hydrate releases as much as 180 cubic feet of methane gas. work at the Mallik site in the Canadian Arctic has established that production of methane from hydrates is technologically feasible. The US national methane hydrate research program is now performing field and laboratory studies designed to accelerate the commercially viable production of methane from hydrate in Alaska. 2005 English 00256501 Mechanical Engineering 127 8-11 U.S. Department of Energy, Natl. Energy Technology Laboratory, Morgantown, WV, United States SUPPL. Heat flow; Methane hydrates; Seismic reflection; Well logs, Computer simulation; Computerized tomography; Diffusion; Dissociation; Hydrates; Mechanical permeability; Natural gas; Nuclear magnetic resonance spectroscopy; Offshore petroleum prospecting; Raman spectroscopy; Sediments; Seismic prospecting, Methane https://www.scopus.com/inward/record.uri?eid=2-s2.0-14644433605&partnerID=40&md5=f9050a60c1916b7a4ceb308d6248c290 cited By 1 R. Boswell article DEMORY2005145 A rock magnetic study was performed on sediment cores from six locations in Lake Baikal. For a comprehensive approach of the processes influencing the rock magnetic signal, additional data are presented such as total organic carbon (TOC), total sulphur (TS), opal, water content and relative variations in iron and titanium measured on selected intervals. In glacial sediments, the magnetic signal is dominated by magnetite, which is considered to be of detrital origin. This predominance of magnetite is interrupted by distinct horizons of authigenic greigite, probably confined to reductive microenvironments. In interglacial stages, besides dilution by biogenic silica and a decreasing detrital input, the weakness of the rock magnetic signal is also due to a reductive dissolution of magnetic particles. The magnetic assemblage is strongly linked to the redox history of interglacial sediment. In the oxidised bottom sediments of Lake Baikal, a biogenic magnetite is observed [Peck, J.A., King, J.W., 1996. Magnetofossils in the sediments of lake Baikal, Siberia. Earth Planet. Sci. Lett. 140 (1–4), 159–172]. After burial under the redox front, the magnetite is preferentially dissolved, and detrital hematite remains dominant when the sedimentation rate is low and when the residence time of the magnetite close to the redox boundary is long. During these low sedimentation rate conditions, the redox front is preserved [Granina, L., Müller, B. and Wehrli, B., 2004. Origin and dynamics of Fe and Mn sedimentary layers in Lake Baikal. Chem. Geol. 205 (1-2), 55-72]. At constant sedimentation rate and fast burial, the magnetite is preserved or transformed into greigite when sulphate-reducing conditions are reached in the sediment. In interglacial sediments, the magnetic assemblages depict changes in the sedimentation rate, which are traced using the ratio of magnetite over hematite (S-ratio). At the beginning of interglacials, the sedimentation rate is constant with an assemblage magnetite+greigite (high S-ratio), and at the end of some interglacials, the sedimentation rate decreases with a predominance of hematite (low S-ratio). Conference paper 2005 English 0921-8181 https://doi.org/10.1016/j.gloplacha.2004.11.010 Global and Planetary Change 46 Elsevier B.V. 145-166 1 Lake Baikal, Late Quaternary, Rock magnetism, Diagenesis, Detrital input https://www.sciencedirect.com/science/article/pii/S0921818104001638 Progress towards reconstructing past climate in Central Eurasia, with special emphasis on Lake Baikal François Demory Hedi Oberhänsli Norbert R. Nowaczyk Matthias Gottschalk Richard Wirth Rudolf Naumann article Rubinstein20051 We use the two target repeating earthquake sequences of SAFOD to identify time varying properties of the shallow crust in the Parkfield area at the surface and in shallow boreholes. At the surface, we find that the 2004 Parkfield earthquake caused direct S wave delays exceeding 7 ms, and S coda delays exceeding 15 ms. We attribute these delays to cracks formed or opened during the strong shaking of the Parkfield earthquake. Observations at depth show that the direct S wave arrival time was much less affected by the Parkfield earthquake. This provides evidence that damage caused by strong shaking (nonlinear strong ground motion), is limited to the very near surface (<100 m). Copyright 2005 by the American Geophysical Union. 2005 English 00948276 10.1029/2005GL023189 Geophysical Research Letters 32 1-5 Department of Geophysics, Stanford University, 397 Panama Mall, Stanford, CA 94305-22215, United States 14 Boreholes; Cracks; Earthquakes; Geologic models; Rock mechanics; Seismic waves; Seismology; Structural geology, Depth constraints; Earthquake sequences; Ground motion; Shallow crust, Tectonics, arrival time; damage; earthquake; ground motion; S-wave, California; North America; Parkfield; United States; Western Hemisphere; World https://www.scopus.com/inward/record.uri?eid=2-s2.0-25444513487&doi=10.1029%2f2005GL023189&partnerID=40&md5=2b8738fba293ed9b66342303a5982585 cited By 90 J.L. Rubinstein G.C. Beroza article Hrubcová20051 The deep structure of the Bohemian Massif (BM), the largest stable outcrop of Var scan rocks in central Europe, was studied using the data of the international seismic refraction experiment Central European Lithospheric Experiment Based on Refraction (CELEBRATION) 2000. The data were interpreted by seismic tomographic inversion and by two-dimensional (2-D) trial-and-error forward modeling of P and S waves. Additional constraint on crustal structure was given by amplitude modeling using the reflectivity method and gravity modeling. Though consolidated, the BM can be subdivided into several tectonic units separated by faults, shear zones, or thrusts reflecting varying influence of the Cadomian and Variscan orogeneses: the Saxothuringian, Barrandian, Moldanubian, and Moravian. Velocity models determine three types of crust-mantle transition in the BM reflecting variable crustal thickness and delimiting contacts of tectonic units in depth. The NW area, the Saxothuringian, has a highly reflective lower crustal layer above Moho with a strong velocity contrast at the top of this layer. This reflective laminated lower crust reaches depths of 26-35 km and is characteristic for the Saxothuringian unit, which was subject to eastward subduction. The Moldanubian in the central part is characterized by the deepest (39 km) and the most pronounced Moho within the whole BM with a strong velocity contrast 6.9-8.1 kin s-1. A thick crust-mantle transition zone in the SE, with velocity increase from 6.8 to 7.8 km s-1 over the depth range of 23-40 km, seems to be the characteristic feature of the Moravian overthrusted by the Moldanubian during Variscan collision. Copyright 2005 by the American Geophysical Union. Article 2005 English 21699313 10.1029/2004JB003080 Journal of Geophysical Research: Solid Earth 110 Blackwell Publishing Ltd 1 – 21 11 Bohemian Massif; Central Europe; Eurasia; Europe; crustal structure; mantle structure; seismic tomography https://www.scopus.com/inward/record.uri?eid=2-s2.0-30144441019&doi=10.1029%2f2004JB003080&partnerID=40&md5=4a6b604a4cc097433310f865dae0e83e Cited by: 129 Pavla Hrubcová P. Środa A. Špičák A. Guterch M. Grad G.R. Keller E. Brueckl H. Thybo article Peterson2005322 During its Classic period (250-950 A.D.), Maya civilization reached a zenith. At its peak, around 750 A.D., the population may have topped 13 million. Then, between about 750 and 950 A.D., their society imploded. The Maya abandoned what had been densely populated urban centers, leaving their impressive stone edifices to fall into ruin. The demise of Maya civilization (which archaeologists call "the terminal Classic collapse") has been one of the great anthropological mysteries of modern times. What could have happened? Scholars have advanced a variety of theories over the years, pinning the fault on everything from internal warfare to foreign intrusion, from widespread outbreaks of disease to a dangerous dependence on monocropping, from environmental degradation to climate change. Some combination of these and other factors may well be where the truth lies. However, in recent years, evidence has mounted that unusual shifts in atmospheric patterns took place near the end of the Classic Maya period, lending credence to the notion that climate, and specifically drought, indeed played a hand in the decline of this ancient civilization. Article 2005 English 00030996 10.1511/2005.54.968 American Scientist 93 Sigma Xi, Scientific Research Society 322 – 329 4 Social aspects; Collapse; Maya civilization; archaeological evidence; demography; Climatology https://www.scopus.com/inward/record.uri?eid=2-s2.0-23144456862&doi=10.1511%2f2005.54.968&partnerID=40&md5=3f1a5f9ad7f799671f4bbc9e1c311e73 Cited by: 52 Larry C. Peterson Gerald H. Haug article Schulte2005191 The combined petrological and rock magnetic study of the Cretaceous-Paleogene (K-P) boundary in northeastern México revealed compositionally and texturally complex Chicxulub ejecta deposits. The predominant silicic ejecta components are Fe-Mg-rich chlorite and Si-Al-K-rich glass spherules with carbonate inclusions and schlieren. Besides these silica phases, the most prominent ejecta component is carbonate. Carbonate occurs as lithic clasts, accretionary lapilli, melt globules (often with quench textures), and as microspar. The composition of the spherules provides evidence for a range of target rocks of mafi c to intermediate composition, presumably situated in the northwestern sector of the Chicxulub impact structure. The abundance of carbonate ejecta suggests that this area received ejecta mainly from shallow, carbonate-rich lithologies. Rare μm-sized metallic and sulfi dic Ni-Corich inclusions in the spherules indicate a possible contamination by meteoritic material. This complex composition underlines the similarities of ejecta in NE México to Chicxulub ejecta from K-P sections worldwide. Although the ejecta display a great variability, the magnetic susceptibility, remanence, and hysteresis properties of the ejecta deposits are fairly homogeneous, with dominantly paramagnetic susceptibilities and a weak ferromagnetic contribution from hematite and goethite. The absence of spinels and the ubiquitous presence of hematite and goethite points to high oxygen fugacity during the impact process. The microfacies and internal texture of the ejecta deposits show welding and fusing of components, as well as evidence for liquid immiscibility between silicic and carbonate melts. No evidence for binary mixing of ejecta phases was found. Therefore, Chicxulub ejecta in NE México probably derived from less energetic parts of the ejecta curtain. However, welding features of ejecta particles and enclosed marl clasts and/or benthic foraminifera from a siliciclastic environment suggest interaction of the-still hot-ejecta curtain with northern Mexican shelf sediments. In addition, an initial ground surge-like ejecta-dispersion mode seems possible. © 2005 Geological Society of America. 2005 10.1130/0-8137-2384-1.191 Special Paper of the Geological Society of America 384 191-221 Geologisches Institut, Universität Karlsruhe (TH), Kaiserstrasse 12, D-76128 Karlsruhe, Germany; Geologisch-Paläontologisches Institut, Universität Heidelberg, Im Neuenheimer Feld 234, D-69120 Heidelberg, Germany; Institut für Geologie, Mineralogie und Geophysik, Ruhr Universität Bochum, Universitätsstrasse 150, D-44801 Bochum, Germany https://www.scopus.com/inward/record.uri?eid=2-s2.0-73949153227&doi=10.1130%2f0-8137-2384-1.191&partnerID=40&md5=6cdf532522181d6b16b89c0071705285 cited By 23 P. Schulte A. Kontny article https://doi.org/10.1029/2005EO360001 Sixty-five million years ago, a large meteorite hit the Earth and formed the ∼200-km-wide Chicxulub crater in Yucatán, Mexico. The well-known, massive extinction event at the Cretaceous-Tertiary (K-T) boundary appears to have been caused, at least in part, by this impact. In the first few seconds after impact the surface of the Earth was pushed down to form a cavity ∼35 km deep, and in the next few hundred seconds this cavity collapsed to form a multi-ring basin with an inner peak ring. To examine the rings and subsurface structure of this superbly preserved impact crater, a seismic experiment was shot across the crater in January and February 2005 by a team of scientists from Mexico, the United States, and the United Kingdom (Figure 1). 2005 https://doi.org/10.1029/2005EO360001 Eos, Transactions American Geophysical Union 86 325-328 36 https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2005EO360001 Jo Morgan Jaime Urrutia-Fucugauchi Sean Gulick Gail Christeson Penny Barton Mario Rebolledo-Vieyra Jay Melosh article haberer2005characterization 2005 10.4095/220702 Scientifique Results from Mallik 2002 Gas Hydrate Production Research Well Program, Mackenzie Delta, Northwest Territories, Canada Geological Survey of Canada, Bulletin 585 Geological Survey of Canada RM Haberer Kai Mangelsdorf V Dieckmann A Fuhrmann Heinz Wilkes Brian Horsfield article Grygar2005389 The sedimentary series from Academician Ridge, Lake Baikal, eastern Siberia, was examined using cation exchange capacity (CEC) to estimate the amount of expandable clay minerals (ECM) and high-temperature X-ray diffraction (HT-XRD) to determine their basic classification. The comparison of the magnetic susceptibility (MS) at sub-millennial resolution and the δ18O record of a reference Atlantic core (ODP 980) was used to create an age model. The most closely studied part of the series covered the major part of the last glacial cycle (120-20 ky BP). The HT-XRD analysis is based on monitoring the course of ECM dehydration with 5°C steps between 25 and 250°C and enabled us to improve the discrimination between ECM, chlorite and micas. The CEC obtained at millennial resolution showed that the neoformation of ECM in warmer periods of the last interglacial was either insignificant or fully compensated by their dissolution or dilution. The CEC record was correlated with the main climatic stages in the period studied. Both MS and CEC records reflected the environmental changes at about millennial resolution, including climatic instabilities between 117 and 73 ky BP (late MIS5). Copyright © 2005, The Clay Minerals Society. Article 2005 English 00098604 10.1346/CCMN.2005.0530407 Clays and Clay Minerals 53 389 – 400 4 Eastern Hemisphere; Eurasia; Lake Baikal; Russian Federation; World; Dehydration; High temperature effects; Magnetic susceptibility; Mineralogy; Positive ions; Sediments; X ray diffraction analysis; clay mineral; lacustrine deposit; physical property; Cation exchange capacity; Paleoclimate; Russia; Thermal dehydration; Clay minerals https://www.scopus.com/inward/record.uri?eid=2-s2.0-24944573446&doi=10.1346%2fCCMN.2005.0530407&partnerID=40&md5=184c222b5070f7bf1aaca2caa09e14e0 Cited by: 18 Tomas Grygar Petr Bezdicka David Hradil Michaela Hruskova Katerina Novotna Jaroslav Kadlec Petr Pruner Hedi Oberhänsli article Frima2005213 The scope of this work is to quantify the impact of calcite cementation on the hydraulic behaviour of an active fault in carbonate rocks. In the studied context, the permeability mainly depends on the fracture network. Therefore the hydraulic regime depends on the way fractures become sealed by vein deposits. The work is based on the study of cores and groundwater recovered from an active normal fault in the Gulf of Corinth, the Aigion fault, in the framework of the Corinth Rift Laboratory Project. The data set includes cores, borehole images, pumping tests and in situ fluid samples. The cores show numerous recent fractures partially, or completely, sealed by recent carbonate crystals. We modelled the fluid-rock interaction to quantify the growth rate of calcite in the veins of this specific geological context. Modelling was carried out with Diaphore, a software designed to study the diagenetic evolution of porosity in hydrocarbon reservoirs. The required time to seal a 1 mm thick fracture in the case of the Aigion fault at 760 m depth was calculated to be within the range of a few hundred years, considering the composition of water sampled at this depth. As a conclusion, diagenetic processes are likely to have a key influence on the fault hydraulic behavior over the time scale of seismic cycles. However, the possibility of calcite growth strongly depends on the composition of the fluid. Tests were made with seawater and slightly higher values of pCO2, a fluid that could also be present around the Aigion fault. In this case dissolution, and therefore opening of the fractures, happens. Copyright © 2005, Institut français du pétrole. Article 2005 English 12944475 10.2516/ogst:2005013 Oil and Gas Science and Technology 60 Editions Technip 213 – 230 2 Calcite; Carbon dioxide; Carbonates; Cement additives; Computer software; Crystal growth; Crystals; Fracture; Groundwater; Hydrocarbons; Mechanical permeability; Porosity; Rocks; Seismology; Carbonate crystals; Carbonate rocks; Diagenetic processes; Hydraulic behaviour; fracture network; hydraulic property; permeability; Hydraulics https://www.scopus.com/inward/record.uri?eid=2-s2.0-20544433195&doi=10.2516%2fogst%3a2005013&partnerID=40&md5=1b74808e770997e7abbee7b39e7ff232 Cited by: 13; All Open Access, Gold Open Access, Green Open Access C. Frima Isabelle Moretti Etienne Brosse F. Quattrocchi L. Pizzino article Dai20051493 Major and trace element data, including platinum group element abundances, of representative impactites and target rocks from the crater rim and environs of the Bosumtwi impact structure, Ghana, have been investigated for the possible presence of a meteoritic component in impact-related rocks. A comparison of chemical data for Bosumtwi target rocks and impactites with those for Ivory Coast tektites and microtektites supports the interpretation that the Bosumtwi structure and Ivory Coast tektites formed during the same impact event. High siderophile element contents (compared to average upper crustal abundances) were determined for target rocks as well as for impactites. Chondrite-normalized (and iron meteorite-normalized) abundances for target rocks and impactites are similar. They do not, however, allow the unambiguous detection of the presence, or identification of the type, of a meteoritic component in the impactites. The indigenous siderophile element contents are high and possibly related to regional gold mineralization, although mineralized samples from the general region show somewhat different platinum-group element abundance patterns compared to the rocks at Bosumtwi. The present data underline the necessity of extensive target rock analyses at Bosumtwi, and at impact structures in general, before making any conclusions regarding the presence of a meteoritic component in impactites. © The Meteoritical Society, 2005. Article 2005 English 10869379 10.1111/j.1945-5100.2005.tb00414.x Meteoritics and Planetary Science 40 University of Arkansas 1493 – 1511 9-10 crater; impact structure; impactite; meteorite; shock metamorphism https://www.scopus.com/inward/record.uri?eid=2-s2.0-29244471693&doi=10.1111%2fj.1945-5100.2005.tb00414.x&partnerID=40&md5=8fe12ac1d0c08a40c6160782d7760e8e Cited by: 19; All Open Access, Bronze Open Access Xiongxin Dai Daniel Boamah Christian Koeberl Wolf Uwe Reimold Gordon Irvine Iain McDonald article Sun20051 In-situ dielectric properties of natural gas hydrate are measured for the first time in the Mallik 5L-38 Well in the Mackenzie Delta, Canada. The average dielectric constant of the hydrate zones is 9, ranging from 5 to 20. The average resistivity is >5 ohm.m in the hydrate zones, ranging from 2 to 10 ohm.m at a 1.1 GHz dielectric tool frequency. The dielectric logs show similar trends with sonic and induction resistivity logs, but exhibits inherently higher vertical resolution (<5 cm). The average in-situ hydrate saturation in the well is about 70%, ranging from 20% to 95%. The dielectric estimates are overall in agreement with induction estimates but the induction log tends to overestimate hydrate content up to 15%. Dielectric estimates could be used as a better proxy of in-situ hydrate saturation in modeling hydrate dynamics. The fine-scale structure in hydrate zones could help reveal hydrate formation history. Copyright 2005 by the American Geophysical Union. 2005 English 00948276 10.1029/2004GL021976 Geophysical Research Letters 32 1-4 Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY 10964, United States 4 Dielectric properties; Electric conductivity; Frequencies; Mathematical models; Natural gas; Dielectric properties; Dielectric properties of gases; Electric logging; Hydration; Induction logging, Dielectric tools; Hydrate saturation; Hydrate zones; Induction logs, Gas hydrates; Gas hydrates, clathrate; dielectric property; gas hydrate, Dielectric methods; Dielectric tools; Fine-scale structures; High resolution; Hydrate formation; Resistivity logs; Situ hydrates; Vertical resolution https://www.scopus.com/inward/record.uri?eid=2-s2.0-19744378644&doi=10.1029%2f2004GL021976&partnerID=40&md5=c82854177ff720bae6d7f50642cfcb45 cited By 20 Y.F. Sun D. Goldberg article Sapota2005355 In this study, results of Be isotopic analyses of sediments collected from the three longest cores drilled in Lake Baikal, i.e. BDP-98 (600 m long), BDP-96 (200 m long) and BDP-93 (102 m long), are presented in relation to their lithological variation. The sediment used in the study has a relatively uniform grain size distribution and mineral composition dominated by detrital feldspars and quartz. Biogenic silica is present in all samples, with amounts up to 40 %. The limited variability in textural and mineralogical (± biogenic silica) composition of the sediment resulted in a constrained 10Be concentration distribution that is mainly related to its production and radioactive decay. Normalization of 10Be to 9Be concentrations shows a trend similar to that of the 10Be distribution. The 10Be-based chronology for the BDP-98 and BDP-96 cores provides time spans of about 8 and 5.5 Myr respectively. Estimation of the 10Be flux indicates high values in the Late Miocene, which can be related to relatively low geomagnetic field intensity during that time. © 2005 E. Schweizerbart'sche Verlagsbuchhandlung. Article 2005 English 00777749 10.1127/njgpa/238/2006/355 Neues Jahrbuch fur Geologie und Palaontologie - Abhandlungen 238 E. Schweizerbart'sche Verlagsbuchhandlung 355 – 411 3 Lake Baikal; Russian Federation; beryllium isotope; core analysis; detrital deposit; feldspar; isotopic analysis; mineralogy; sediment analysis https://www.scopus.com/inward/record.uri?eid=2-s2.0-31844439221&doi=10.1127%2fnjgpa%2f238%2f2006%2f355&partnerID=40&md5=9e303aa141925240ec3bbc9b2f85cb7c Cited by: 0 Tomasz Sapota Ala Aldahan Göran Possnert article Lawton200581 Ejecta-bearing strata are present at the top of Cretaceous foreland-basin deposits throughout the La Popa basin in northeastern Mexico. In the southeast part of the basin, locally thick (as much as 4.6 m) ejecta-rich conglomeratic strata occupy valley-like features at a bathymetric break that separated Maastrichtian upper shoreface from lower shoreface and prodelta depositional settings. Clast-supported textures, normally graded planar conglomerate-sandstone couplets, upcurrent-dipping low-angle cross-laminae, sparse paleocurrent data, and transported fossils indicate deposition by south- to southeast-directed turbulent, supercritical flow. In the northwest part of the basin, ejecta grains are present but less common in correlative deposits. Sediment, ejecta, and organisms were eroded from shoreward environments and transported basinward by backflow of run-up surge(s) emplaced against the continent by one or several tsunami(s). High-discharge, supercritical offshore-directed flow provides a mechanism for transport of voluminous, ejecta-bearing sediment and late Maastrichtian marine organisms into deep-water Gulf of Mexico settings. © 2005 Geological Society of America. 2005 10.1130/G21057.1 Geology 33 81-84 Institute of Tectonic Studies, New Mexico State University, Las Cruces, NM 88003, United States; Instituto de Geología, Univ. Nac. Autonoma de Mexico, Ciudad Universitaria, Coyoacán, D.F. 04510, Mexico 2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-13944275932&doi=10.1130%2fG21057.1&partnerID=40&md5=15a768335edf0be07bf122810a38602f cited By 49 T.F. Lawton K.W. Shipley J.L. Aschoff K.A. Giles F.J. Vega article Shervais200527 Basaltic volcanism in the Snake River Plain of southern Idaho has long been associated with the concept of a mantle plume that was overridden by North America during the Neogene and now resides beneath the Yellowstone plateau. This concept is consistent with the time-transgressive nature of rhyolite volcanism in the plain, but the history of basaltic volcanism is more complex. In the eastern Snake River Plain, basalts erupted after the end of major silicic volcanism. The basalts typically erupt from small shield volcanoes that cover up to 680 km 2 and may form elongate flows that extend 50-60 km from the central vent. The shields coalesce to form extensive plains of basalt that mantle the entire width of the plain, with the thickest accumulations of basalt forming an axial high along the length of the plain. In contrast, basaltic volcanism in the western Snake River Plain formed in two episodes: the first (ca. 7-9 Ma) immediately following the eruption of rhyolites lavas now exposed along the margins of the plain, and the second forming in the Pleistocene (δ2 Ma), long after active volcanism ceased in the adjacent eastern Snake River Plain. Pleistocene basalts of the western Snake River Plain are intercalated with, or overlie, lacustrine sediments of Pliocene-Pleistocene Lake Idaho, which filled the western Snake River Plain graben after the end of the first episode of basaltic volcanism. The contrast in occurrence and chemistry of basalt in the eastern and western plains suggest the interpretation of volcanism in the Snake River Plain is more nuanced than simple models proposed to date. © 2005 Geological Society of America. 2005 English 10.1130/2005.fld006(02) GSA Field Guides 6 Geological Society of America 27-52 Department of Geology, Utah State University, Logan, UT 84322-4505, United States; Idaho Geological Survey, University of Idaho, Moscow, ID 83844-3014, United States; Idaho Geological Survey, Boise State University, Boise, ID 83725-1535, United States; Department of Geology, Centenary College, Shreveport, LA 71134, United States; Department of Geological Sciences, University of South Carolina, Columbia, SC 29208, United States; Department of Geological Sciences, San Diego State University, San Diego, CA 92182-1020, United States Granite; Rivers, Basalt geochemistry; Basaltic volcanism; First episodes; Lacustrine sediments; Mantle plume; Silicic volcanism; Snake river plains; Yellowstones, Basalt https://www.scopus.com/inward/record.uri?eid=2-s2.0-85065264109&doi=10.1130%2f2005.fld006%2802%29&partnerID=40&md5=a913f9d79d0f1515b6795e68f79261f0 cited By 24 J.W. Shervais J.D. Kauffman V.S. Gillerman K.L. Othberg S.K. Vetter R.V. Hobson M. Zarnetske M.F. Cooke S.H. Matthews B.B. Hanan article Tagle20052877 With a diameter of ∼100 km, Popigai in Northern Siberia is the largest crater known in the Cenozoic. The concentrations in platinum group elements (PGE) were analyzed in twenty samples of homogeneous impact melt collected in the northwestern flank of the crater to identify the composition of the projectile. The method selected was preconcentration by NiS fire assay followed by inductively coupled plasma-mass spectrometry (ICP-MS). This technique measures all the PGE (except Os) and by using aliquots >10g, the results are highly reproducible. The major and trace element composition of the impact melt resembles that of gneissic lithologies of the Anabar shield, which are representative of the target rock. The PGE are enriched in the melt by factors of 3 to 14 compared to the main target lithology, but the meteoritic contamination is only around 0.2 wt.%. Using plots of elemental ratios such as Ru/Rh vs. Pt/Pd or Ru/Rh vs. Pd/Ir, the Popigai impactor is clearly identified as an ordinary chondrite and most likely l-chondrite. This study indicates that PGE elemental ratios allow discrimination of the type of impactor, even in the case of low meteoritic contamination. This study confirms that a significant fraction of the crater-forming projectiles presently documented could have an ordinary chondrite composition. Their probable source, the S-type asteroids, appears to form the majority of the bodies in the main asteroid belt and among Near Earth Objects (NEOs). The ordinary chondrite origin of the Popigai projectile supports an asteroidal origin for the late Eocene impacts as a plausible alternative to the comet shower scenario proposed by Farley et al. (1998). Copyright © 2005 Elsevier Ltd. 2005 10.1016/j.gca.2004.11.024 Geochimica et Cosmochimica Acta 69 2877-2889 Institut für Mineralogie, Museum für Naturkunde, D-10099 Berlin, Germany; Dept. of Geology, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium 11 https://www.scopus.com/inward/record.uri?eid=2-s2.0-20344393592&doi=10.1016%2fj.gca.2004.11.024&partnerID=40&md5=acd32f2bee196156ec6df99a896721a0 cited By 61 R. Tagle P. Claeys article Sobolev2005590 More than 50 per cent of the Earth's upper mantle consists of olivine and it is generally thought that mantle-derived melts are generated in equilibrium with this mineral. Here, however, we show that the unusually high nickel and silicon contents of most parental Hawaiian magmas are inconsistent with a deep olivine-bearing source, because this mineral together with pyroxene buffers both nickel and silicon at lower levels. This can be resolved if the olivine of the mantle peridotite is consumed by reaction with melts derived from recycled oceanic crust, to form a secondary pyroxenitic source. Our modelling shows that more than half of Hawaiian magmas formed during the past 1 Myr came from this source. In addition, we estimate that the proportion of recycled (oceanic) crust varies from 30 per cent near the plume centre to insignificant levels at the plume edge. These results are also consistent with volcano volumes, magma volume flux and seismological observations. 2005 English 00280836 10.1038/nature03411 Nature 434 590-597 Max-Planck-Institut für Chemie, Postfach 3060, 55020 Mainz, Germany; Vernadsky Institute of Geochemistry, Russian Academy of Sciences, Kosygin street 19, 117975 Moscow, Russian Federation; GeoForschungsZentrum, Telegrafenberg E, D-14473, Potsdam, Germany; Institute of Physics of the Earth, Russian Academy of Sciences, B. Gruzinskaya street 10, 123995 Moscow, Russian Federation; Faculty of Geosciences, Department of Petrology, Utrecht University, Budapestlaan 4, 3584 CD Utrecht, Netherlands; Faculty of Earth and Life Sciences, Department of Petrology, Vrije Universiteit, De Boelelaan 1085, 1081 HV, Amsterdam, Netherlands 7033 Mathematical models; Minerals; Nickel; Seismology; Silicon; Volcanoes, Magmas; Mantle; Pyroxene; Recycled oceanic crusts, Basalt, mineral; nickel; silicon, basalt; mantle; petrogenesis; petrology, article; basalt; model; plume; priority journal; sea; United States; volcano, Hawaiian Islands; oceanic regions; Pacific islands; Pacific Ocean; World https://www.scopus.com/inward/record.uri?eid=2-s2.0-16844372977&doi=10.1038%2fnature03411&partnerID=40&md5=82fd9665dc87eac7423b1b5fc7ab8717 cited By 873 A.V. Sobolev A.W. Hofmann S.V. Sobolev I.K. Nikogosian article Walton2005 The Hawaii Scientific Drilling Project 2 Phase 1 core permits study of each stage of alteration of basalt glass during burial because stages of the process are separated vertically. Previous work has shown that alteration of hyaloclastite occurs progressively. The latest stage observed in the Phase 1 core involves marginal replacement of sideromelane in shards with palagonite while simultaneously forming chabazite in pores. The basic reaction at this stage is sideromelane + components from pore waters = palagonite + chabazite + components to pore waters. Mass balance calculations show that Fe was virtually immobile in this process, being retained in palagonite. Na, Ca, Ba, P, Al, and Si were lost during palagonitization and not fully consumed in making chabazite. Mg was lost during palagonitization but retained elsewhere in smectite. K, Rb, and Sr were extracted from pore waters and enriched in the sum of the alteration products. The amount of enrichment depended upon the amount of chabazite present, which depended upon the porosity when chabazite formed. Ti, Y, U, Zr, Nb, REE, and Th were enriched in palagonite, compared to sideromelane, but were absent in chabazite. Mass balance of all phases for the entire alteration process (including earlier stages) was not possible because poorly consolidated samples do not yield accurate modal values of phases, trace element analysis of smectite was not possible, and exchange with lavas and intrusions in the succession cannot be evaluated. Calculations indicate that too little of major oxides, except Na2O, was released during palagonitization to account for the amount of smectite observed in hyaloclastites. The results of this study, and several others published in the literature, indicate that under various circumstances palagonitization will consume particular elements from pore fluid or release them to it. Such mobility implies that the hydrology of the particular system and the composition of the dissolved solids in the pore water will control whether palagonitization is a source or sink of elements. The potential exists that palagonitization of basalt glass is an important source or sink of elements for seawater and fluids circulating in the ocean crust. Copyright 2005 by the American Geophysical Union. 2005 English 15252027 10.1029/2004GC000903 Geochemistry, Geophysics, Geosystems 6 Department of Geology, University of Kansas, 120 Lindley Hall, 1475 Jayhawk Boulevard, Lawrence, KS 66045, United States; Department of Geology, University of California, Davis, One Shields Boulevard, Davis, CA 95616-8605, United States 9 https://www.scopus.com/inward/record.uri?eid=2-s2.0-34548488663&doi=10.1029%2f2004GC000903&partnerID=40&md5=d3feaf18965eed8fbcc1353632fd3dc9 cited By 34 A.W. Walton P. Schiffman G.L. MacPherson article Scasso2005283 A coarse-grained sandstone bed of Cretaceous/Paleogene (K/Pg) boundary age occurs in a homogeneous neritic shelf mudstone sequence (Jagüel Formation) in the Neuquén Basin of Argentina. This bed, 15 - 25 cm thick, contains abundant plagioclase, broken shells and sharks' teeth. Sedimentological features include an erosive base, abundant rip-up clasts, normal grading and hummocky cross-bedding. The K/Pg boundary age of the bed was confirmed by calcareous nannofossils. Similar to other sections in the Gulf Coast region and the Danish Basin, a "dead zone" significantly depleted in macrofossils is evident in the basal 1 m above the clastic layer. In combination, these features suggest that the clastic layer represents a tsunami deposit that was related to the Chicxulub impact event in Yucatan/Mexico. Mechanisms of tsunami wave amplification in this extremely distal and somewhat protected setting are poorly understood but the funnel-shape of the basin may have promoted the unusually strong sedimentological response. © 2005 Elsevier Ltd. All rights reserved. 2005 10.1016/j.cretres.2004.12.003 Cretaceous Research 26 283-297 Departamento de Ciencias Geologicas, FCEN, Universidad de Buenos Aires, 1428 Buenos Aires, Argentina; Museum für Naturkunde, Institut für Paläontologie, Humboldt-Universität Berlin, Invalidenstr. 43, D-10115 Berlin, Germany; Museum für Naturkunde, Institut für Mineralogie, Humboldt-Universität Berlin, Invalidenstr. 43, D-10115 Berlin, Germany 2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-17444383780&doi=10.1016%2fj.cretres.2004.12.003&partnerID=40&md5=bd45acb20457f4a3089ab5852a0f7dec cited By 35 R.A. Scasso A. Concheyro M. Aberhan L. Hecht F.A. Medina R. Tagle article Sanford2005185 Groundwater more saline than seawater has been discovered in the tsunami breccia of the Chesapeake Bay impact Crater. One hypothesis for the origin of this brine is that it may be a liquid residual following steam separation in a hydrothermal system that evolved following the impact. Initial scoping calculations have demonstrated that it is feasible such a residual brine could have remained in the crater for the 35 million years since impact. Numerical simulations have been conducted using the code HYDROTHERM to test whether or not conditions were suitable in the millennia following the impact for the development of a steam phase in the hydrothermal system. Hydraulic and thermal parameters were estimated for the bedrock underlying the crater and the tsunami breccia that fills the crater. Simulations at three different breccia permeabilities suggest that the type of hydrothermal system that might have developed would have been very sensitive to the permeability. A relatively low breccia permeability (1 × 10-16 m2) results in a system partitioned into a shallow water phase and a deeper superheated steam phase. A moderate breccia permeability (1 × 10-15 m2 ) results in a system with regionally extensive multiphase conditions. A relatively high breccia permeability (1 × 10-14 m2 ) results in a system dominated by warm-water convection cells. The permeability of the crater breccia could have had any of these values at given depths and times during the hydrothermal system evolution as the sediments compacted. The simulations were not able to take into account transient permeability conditions, or equations of state that account for the salt content of seawater. Results suggest, however, that it is likely that steam conditions existed at some time in the system following impact, providing additional evidence that is consistent with a hydrothermal origin for the crater brine. © Blackwell Publishing Ltd. 2005 English 14688115 10.1111/j.1468-8123.2005.00110.x Geofluids 5 185-201 U.S. Geological Survey, 12201 Sunrise Valley Dr., Reston, VA 20192, United States 3 bolide; hydrothermal circulation; impact structure, Chesapeake Bay; North America; United States; Western Hemisphere; World https://www.scopus.com/inward/record.uri?eid=2-s2.0-22744445158&doi=10.1111%2fj.1468-8123.2005.00110.x&partnerID=40&md5=6dd99367743a9414b4e712f7c96dc329 cited By 31 W.E. Sanford article Osinski20051789 Contrary to the previous interpretation of a single allochthonous impactite lithology, combined field, optical, and analytical scanning electron microscopy (SEM) studies have revealed the presence of a series of impactites at the Haughton impact structure. In the crater interior, there is a consistent upward sequence from parautochthonous target rocks overlain by parautochthonous lithic (monomict) breccias, through allochthonous lithic (polymict) breccia, into pale grey allochthonous impact melt breccias. The groundmass of the pale grey impact melt breccias consists of microcrystalline calcite, silicate impact melt glass, and anhydrite. Analytical data and microtextures indicate that these phases represent a series of impact-generated melts that were molten at the time of, and following, deposition. Impact melt glass clasts are present in approximately half of the samples studied. Consideration of the groundmass phases and impact glass clasts reveal that impactites of the crater interior contain shock-melted sedimentary material from depths of >920 to <1880 m in the pre-impact target sequence. Two principal impactites have been recognized in the near-surface crater rim region of Haughton. Pale yellow-brown allochthonous impact melt breccias and megablocks are overlain by pale grey allochthonous impact melt breccias. The former are derived from depths of >200 to <760 m and are interpreted as remnants of the continuous ejecta blanket. The pale grey impact melt breccias, although similar to the impact melt breccias of the crater interior, are more carbonate-rich and do not appear to have incorporated clasts from the crystalline basement. Thus, the spatial distribution of the crater-fill impactites at Haughton, the stratigraphic succession from target rocks to allochthonous impactites, the recognition of large volumes of impact melt breccias, and their probable original volume are all analogous to characteristics of coherent impact melt layers in comparatively sized structures formed in crystalline targets. © The Meteoritical Society, 2005. 2005 10.1111/j.1945-5100.2005.tb00147.x Meteoritics and Planetary Science 40 1789-1812 Planetary and Space Science Centre, Department of Geology, University of New Brunswick, 2 Bailey Drive, Fredericton, NB E3B 5A3, Canada; Canadian Space Agency, 6767 Route de l'Aeroport, Saint-Hubert, Que. J3Y 8Y9, Canada; Mars Institute, NASA Ames Research Center, Moffett Field, CA 94035-1000, United States 12 https://www.scopus.com/inward/record.uri?eid=2-s2.0-33244466987&doi=10.1111%2fj.1945-5100.2005.tb00147.x&partnerID=40&md5=da09b23d420ccb4a96027d24d6eea642 cited By 51 G.R. Osinski J.G. Spray P. Lee article Khursevich200595 Detailed diatom zonation in the Lake Baikal holostratotype section BDP-96-2 is extended over the interval 0.85-1.25 Ma and compared with diatom assemblage composition from the new BDP-99 drill core. Interglacial diatom assemblages at these two sites over 220 km apart are of similar composition, and the same complete and continuous succession of diatom zones is observed in both drill cores over the 0-800 ka interval. We propose a correlation of Baikal diatomaceous intervals with the marine oxygen isotope stratigraphy and with European climato-stratigraphic divisions of the early Pleistocene. We then use the diatom succession in BDP-96-2 to demonstrate evidence for disconformity in BDP-99 and to establish an approximate age model for this section. Diatom assemblages characteristic of the top of the Matuyama reversed polarity interval and the upper part of the Jaramillo normal polarity subchron are not found in the BDP-99 section below the disconformity boundary. The lack of diatom zones corresponding to the MIS 21-27 of the marine oxygen isotope stratigraphy in BDP-99 section suggests that the estimated age span of missing sediment interval in BDP-99 is ca 150-160 ka. The unusual diatom assemblage of cosmopolitan species during MIS 33 in both BDP-96-2 and BDP-99 drill core sections is indicative of abrupt ecological changes in the time interval 1.12-1.08 Ma. © 2004 Elsevier Ltd and INQUA. All rights reserved. Article 2005 English 10406182 10.1016/j.quaint.2004.11.011 Quaternary International 136 Elsevier Ltd 95 – 104 1 SPEC. ISS. Eastern Hemisphere; Eurasia; Lake Baikal; Russian Federation; World; biostratigraphy; community composition; diatom; marine isotope stage; sediment core https://www.scopus.com/inward/record.uri?eid=2-s2.0-17144394746&doi=10.1016%2fj.quaint.2004.11.011&partnerID=40&md5=95724c30e6b979c3185e501aa3c14823 Cited by: 25 Galina K. Khursevich Alexander A. Prokopenko Svetlana A. Fedenya Lilia I. Tkachenko Douglas F. Williams article Osinski20051859 The well-preserved state and excellent exposure at the 39 Ma Haughton impact structure, 23 km in diameter, allows a clearer picture to be made of the nature and distribution of hydrothermal deposits within mid-size complex impact craters. A moderate- to low-temperature hydrothermal system was generated at Haughton by the interaction of groundwaters with the hot impact melt breccias that filled the interior of the crater. Four distinct settings and styles of hydrothermal mineralization are recognized at Haughton: a) vugs and veins within the impact melt breccias, with an increase in intensity of alteration towards the base; b) cementation of brecciated lithologies in the interior of the central uplift; c) intense veining around the heavily faulted and fractured outer margin of the central uplift; and d) hydrothermal pipe structures or gossans and mineralization along fault surfaces around the faulted crater rim. Each setting is associated with a different suite of hydrothermal minerals that were deposited at different stages in the development of the hydrothermal system. Minor, early quartz precipitation in the impact melt breccias was followed by the deposition of calcite and marcasite within cavities and fractures, plus minor celestite, barite, and fluorite. This occurred at temperatures of at least 200 °C and down to ∼100-120 °C. Hydrothermal circulation through the faulted crater rim with the deposition of calcite, quartz, marcasite, and pyrite, occurred at similar temperatures. Quartz mineralization within breccias of the interior of the central uplift occurred in two distinct episodes (∼250 down to ∼90 °C, and <60 °C). With continued cooling (<90 °C), calcite and quartz were precipitated in vugs and veins within the impact melt breccias. Calcite veining around the outer margin of the central uplift occurred at temperatures of ∼150 °C down to <60 °C. Mobilization of hydrocarbons from the country rocks occurred during formation of the higher temperature calcite veins (>80 °C). Appreciation of the structural features of impact craters has proven to be key to understanding the distribution of hydrothermal deposits at Haughton. © The Meteoritical Society, 2005. 2005 10.1111/j.1945-5100.2005.tb00150.x Meteoritics and Planetary Science 40 1859-1877 Lunar and Planetary Laboratory, University of Arizona, 1629 East University Boulevard, Tucson, AZ 85721-0092, United States; Canadian Space Agency, 6767 Route de l'Aéroport, Saint-Hubert, Que. J3Y 8Y9, Canada; SETI Institute, NASA Ames Research Center, MS 245-3, Moffett Field, CA 94035-1000, United States; Geofluids Research Group, Department of Geology and Petroleum Geology, University of Aberdeen, Aberdeen AB24 3UE, United Kingdom; Planetary and Space Science Centre, Department of Geology, University of New Brunswick, 2 Bailey Drive, Fredericton, NB E3B 5A3, Canada 12 https://www.scopus.com/inward/record.uri?eid=2-s2.0-18944377646&doi=10.1111%2fj.1945-5100.2005.tb00150.x&partnerID=40&md5=c665111c97b972b2c0638646d5af3f24 cited By 86 G.R. Osinski P. Lee J. Parnell J.G. Spray M. Baron conference Taylor20052657 In conjunction with the US Geological Survey, Duke University has collected several unique datasets at the site of the San Andreas Fault Observatory at Depth (SAFOD). As part of ongoing seismic studies at SAFOD, we acquired a seismic dataset which used drill bit energy as a seismic source during the summer of 2004. The purpose of this experiment was to collect an inverse vertical seismic profile from signals generated by the drill bit while the SAFOD borehole was being drilled. To develop the profile discussed in this report, we utilized a surface array of vertical component geophones that were deployed along the azimuth proposed for the deviated borehole which is now instrumented as a subsurface observatory. While a well is being drilled, the drill bit produces low level seismic energy as it crushes rock fragments and moves downward through the rock. During drilling of the SAFOD well, we simultaneously recorded these signals using accelerometers mounted on the topdrive of the drill rig as well as a 46 channel surface array of vertical component geophones. The data collected during this study has provided us with valuable seismic information which supplements our previous data of spatially coarse vertical seismic profiles. We now have seismic data based on 10m subsurface source interval to use for interpretation of the physical properties of rocks in the study area. © Society of Exploration Geophysicists - 75th SEG International Exposition and Annual Meeting, SEG 2005. All rights reserved. 2005 English 9781604236101 10.1190/1.2148271 Society of Exploration Geophysicists - 75th SEG International Exposition and Annual Meeting, SEG 2005 Society of Exploration Geophysicists 2657-2660 Duke University, United States; Schlumberger-Doll Research, United States; WesternGeco, United Kingdom Bits; Boreholes; Drills; Geophysical prospecting; Infill drilling; Observatories; Seismic waves; Strike-slip faults, San Andreas fault; Seismic imaging; Seismic information; Seismic studies; Subsurface source; US Geological Survey; Vertical component; Vertical seismic profiles, Seismology https://www.scopus.com/inward/record.uri?eid=2-s2.0-28144447188&doi=10.1190%2f1.2148271&partnerID=40&md5=1483bb054ef7ad6eb38091a82bd54b0d cited By 4 S. Taylor P. Malin E. Shalev J.B.U. Haldorsen R. Coates C. Stolte article Bryce2005 Sr, Nd, and Os isotopic measurements were made on 110 Mauna Kea lava and hyaloclastite samples from the drillcore retrieved from the second phase of the Hawaii Scientific Drilling Project (HSDP-2). The samples come from depths of 255 to 3098 meters below sea level, span an age range from 200 to about 550-600 kyr, and represent an ordered record of the lava output from Mauna Kea volcano as it drifted a distance of about 40 km over the magma-producing region of the Hawaiian hot spot. The deepest (oldest) samples represent the time when Mauna Kea was closest to the center of the melting region of the Hawaiian plume. The Sr and Os isotopic ratios in HSDP-2 lavas show only subtle isotopic shifts over the ∼400 kyr history represented by the core. Neodymium isotopes (∈Nd values) increase systematically with decreasing age from an average value of nearly +6.5 to an average value of +7.5. This small change corresponds to subtle shifts in 87Sr/86Sr and 187Os/188Os isotope ratios, with small shifts of ∈Hf, a large shift in 208Pb/204Pb and 208Pb/207Pb values, and with a very large shift in He isotope ratios from R/RA values of about 7-8 to values as high as 25. When Mauna Kea was closest to the plume core, the magma source did not have primitive characteristics for Nd, Sr, Pb, Hf, and Os isotopes but did have variable amounts of "primitive" helium. The systematic shifts in Nd, Hf, Pb, and He isotopes are consistent with radial isotopic zoning within the melting region of the plume. The melting region constitutes only the innermost, highest-temperature part of the thermally anomalous plume mantle. The different ranges of values observed for each isotopic system, and comparison of Mauna Kea lavas with those of Mauna Loa, suggest that the axial region of the plume, which has a radius of ∼20 km, is a mixture of recycled subducted components and primitive lower mantle materials, recently combined during the formational stages of the plume at the base of the mantle. The proportions of recycled and primitive components are not constant, and this requires there be longitudinal (vertical) heterogeneity within the core of the plume. The remainder of the plume, outside this plume "core zone," is less heterogeneous but distinct from upper mantle as represented by mid-ocean ridge basalt (MORB). The plume structure may provide a detailed view of mantle isotopic composition near the core-mantle boundary. Copyright 2005 by the American Geophysical Union. 2005 English 15252027 10.1029/2004GC000809 Geochemistry, Geophysics, Geosystems 6 Center for Isotope Geochemistry, Department of Earth and Planetary Science, University of California, Berkeley, CA 94720-4767, United States; Department of Earth Sciences, University of New Hampshire, James Hall, 56 College Road, Durham, NH 03824, United States; Max-Planck Institut für Chemie, Postfach 3060, D-55020 Mainz, Germany; Geological Sciences Department, University of Texas at Austin, 1 University Station C1100, Austin, TX 78712-0254, United States 9 https://www.scopus.com/inward/record.uri?eid=2-s2.0-33750609019&doi=10.1029%2f2004GC000809&partnerID=40&md5=61a45362363bbef1694a2566dac3307f cited By 90 J.G. Bryce D.J. DePaolo J.C. Lassiter article Turtle20051 The diameter of an impact crater is one of the most basic and important parameters used in energy scaling and numerical modeling of the cratering process. However, within the impact and geological communities and literature, there is considerable confusion about crater sizes due to the occurrence of a variety of concentric features, any of which might be interpreted as defining a crater's diameter. The disparate types of data available for different craters make the use of consistent metrics difficult, especially when comparing terrestrial to extraterrestrial craters. Furthermore, assessment of the diameters of terrestrial craters can be greatly complicated due to post-impact modification by erosion and tectonic activity. We analyze the terminology used to describe crater geometry and size and attempt to clarify the confusion over what exactly the term "crater diameter" means, proposing a consistent terminology to help avert future ambiguities. We discuss several issues of crater-size in the context of four large terrestrial examples for which crater diameters have been disputed (Chicxulub, Sudbury, Vredefort, and Chesapeake Bay) with the aim of moving toward consistent application of terminology. © 2005 Geological Society of America. 2005 10.1130/0-8137-2384-1.1 Special Paper of the Geological Society of America 384 1-24 Lunar and Planetary Laboratory, Department of Planetary Sciences, University of Arizona, Tucson, AZ 85721-0092, United States; Planetary Science Institute, 1700 E. Fort Lowell, Tucson, AZ 85719-2395, United States; Department of Earth Science and Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom; Impact Cratering Research Group, School of Geosciences, University of the Witwatersrand, Private Bag 3, Wits 2050, Johannesburg, South Africa; Canadian Space Agency, 6767 Route de l'Aeroport, Saint-Hubert, QC J3Y 8Y9, Canada https://www.scopus.com/inward/record.uri?eid=2-s2.0-73949102617&doi=10.1130%2f0-8137-2384-1.1&partnerID=40&md5=23d21d9a5fa01676fb8d016a97934942 cited By 106 E.P. Turtle E. Pierazzo G.S. Collins G.R. Osinski H.J. Melosh J.V. Morgan W.U. Reimold article Kring20051 The Chicxulub and Ries impact craters were excavated from layered continental terrains that were composed of carbonate-bearing sedimentary sequences and underlying crystalline silicate basement materials. The Chicxulub and Ries impact events were sufficiently large to produce complex peak-ring impact craters. The walls of transient craters and excavation cavities, with diameters of 12-16 km for the Ries and 90-100 km for Chicxulub, collapsed to form final crater diameters of ∼24 and ∼180 km, respectively. Debris from both the sedimentary and crystalline layers was ejected during crater formation, but the bulk of the melting occurred at depth, in the silicate basement. The volume of melt and proportion of melt among shock-metamorphosed debris was far larger at Chicxulub, producing a central melt sheet ∼3 km in depth. The central melt sheet was covered with melt-bearing polymict breccias and, at the Ries, similar breccias (crater suevites) filled the central cavity. Also at the Ries (and presumably at Chicxulub), large hill-size megablocks of crystalline basement material were deposited near the transient crater rim. Blocks and megablocks of sedimentary lithologies were ejected into the modification zone between the peak ring and final crater rim, while additional material was slumping inward during crater growth, and buried beneath a fallout deposit of melt-bearing polymict breccias. The melt and surviving clasts in the breccias are dominantly derived from the deeper, basement lithologies. At greater distances, however, the ejecta is dominated by near-surface sedimentary lithologies, large blocks of which landed with such high energy that they scoured and eroded the pre-existing surface. The excavation and ejecta pattern produced lithological and chemical variations with radial distance from the crater centers that evolve from basement components near the crater centers to sedimentary components far from the crater centers. In addition, carbonate (and anhydrite in the case of Chicxulub) was vaporized, producing environmentally active gases. The vaporized volume produced by the Ries impact event was too small to dramatically alter the evolution of life, but the vaporized volume produced by the Chicxulub impact event is probably a key factor in the Cretaceous-Tertiary boundary mass extinction event. © 2004 Elsevier GmbH. All rights reserved. 2005 10.1016/j.chemer.2004.10.003 Chemie der Erde 65 1-46 Lunar and Planetary Laboratory, University of Arizona, 1629 E. University Blvd., Tucson, AZ 85721, United States 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-13644259335&doi=10.1016%2fj.chemer.2004.10.003&partnerID=40&md5=5b2173e7027150cfff0ee19159d94331 cited By 58 D.A. Kring article Pirajno2005587 Meteorite impacts cause conversion of kinetic energy into thermal energy. Part of this thermal energy is used to form a melt sheet, part is dissipated to heat the target rocks and these together with the hot rocks that elastically rebound from the depth of several kilometres (central uplift) activate hydrothermal circulation. Impact-generated hydrothermal systems have been documented from several impact structures world-wide. Three Australian examples-Shoemaker, Woodleigh and Yarrabubba-provide evidence of hydrothermal fluid flow both within and around the structures. Field observations, and petrographic and geochemical data suggest a common evolutionary trend of post-impact hydrothermal activity from early high-temperature alkali metasomatism to a later lower temperature H+ metasomatism, resulting in the overprinting by hydrous mineral assemblages. Hydrothermal systems activated by meteorite-impact events are important because they may also form economic mineral deposits, as is documented for several impact structures in the world. A working model of hydrothermal circulation in terrestrial impact structures posits two main stages: (i) initial high-temperature fluids percolate downward causing widespread alkali metasomatism of the shattered target rocks below the melt sheet, resulting in their modification to rocks of syenitic affinity; and (ii) inflow of meteoric water and progressive cooling of the melt sheet leads to a lower temperature stage, in which hydrothermal fluid flow tends to move upward, resulting in mineral assemblages and alteration patterns that resemble those of epithermal systems. In addition, these fluids can discharge at the surface as hot springs. © Geological Society of Australia. 2005 10.1080/08120090500170468 Australian Journal of Earth Sciences 52 587-605 Geological Survey of Western Australia, 100 Plain Street, East Perth, WA 6004, Australia 4-5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-27344457427&doi=10.1080%2f08120090500170468&partnerID=40&md5=2e5e9aa1e78f749314b4376625470230 cited By 25 F. Pirajno article Osinski2005202 Combined field studies, optical and scanning electron microscopy, and electron microprobe studies of impactites from the Ries impact structure, Germany, have allowed a clearer picture of the hydrothermal system associated with the Ries impact event to be made. Hydrothermal alteration is concentrated within impact-generated suevites in the interior of the crater (crater suevites) and around the periphery (surficial suevites), with minor alteration in the overlying sedimentary crater-fill deposits. The major heat source for the Ries hydrothermal system was the suevite units themselves. Hydrothermal alteration of crater-fill suevites is pervasive in nature and comprises several distinct alteration phases that vary with depth. An early phase of K-metasomatism accompanied by minor albitization of crystalline basement clasts and minor chloritization, was followed by pervasive intermediate argillic alteration (predominantly montmorillonite, saponite, and illite) and zeolitization (predominantly analcite, erionite, and clinoptilolite). Hydrothermal fluids were typically weakly alkaline during the main stage of alteration. In contrast to the crater-fill suevites, alteration within surficial suevites was typically restricted to montmorillonite and phillipsite deposition within cavities and fractures. The pervasive nature of the alteration within the crater-fill suevites was likely due to the presence of an overlying crater lake; whereas alteration within surficial suevites typically occurred under undersaturated conditions with the main source of water being from precipitation. There are exceptional outcrops of more pervasively altered surficial suevites, which can be explained as locations where water pooled for longer periods of time. Hydrothermal fluids were likely a combination of meteoric waters that percolated down from the overlying crater lake and groundwaters that flowed in from the surrounding country rocks. © 2005 Blackwell Publishing Ltd. 2005 10.1111/j.1468-8123.2005.00119.x Geofluids 5 202-220 Canadian Space Agency, 6767 Route de l'Aeroport, Saint-Hubert, Que. J3Y 8Y9, Canada 3 https://www.scopus.com/inward/record.uri?eid=2-s2.0-22744458934&doi=10.1111%2fj.1468-8123.2005.00119.x&partnerID=40&md5=3df8be2ed9c0aabec36de13a96914b80 cited By 64 G.R. Osinski article Baker2005655 A growing number of sites in the Northern Hemisphere show centennial- to millennial-scale climate variation that has been correlated with change in solar variability or with change in North Atlantic circulation. However, it is unclear how (or whether) these oscillations in the climate system are manifest in the Southern Hemisphere because of a lack of sites with suitably high sampling resolution. In this paper, we reconstruct the lake-level history of Lake Titicaca, using the carbon isotopic content of sedimentary organic matter, to evaluate centennial- to millennial-scale precipitation variation and its phasing relative to sites in the Northern Hemisphere. The pattern and timing of lake-level change in Lake Titicaca is similar to the ice-rafted debris record of Holocene Bond events, demonstrating a possible coupling between precipitation variation on the Altiplano and North Atlantic sea-surface temperatures (SSTs). The cold periods of the Holocene Bond events correspond with periods of increased precipitation on the Altiplano. Holocene precipitation variability on the Altiplano is anti-phased with respect to precipitation in the Northern Hemisphere monsoon region. More generally, the tropical Andes underwent large changes in precipitation on centennial-to-millennial timescales during the Holocene. Copyright © 2005 John Wiley & Sons, Ltd. Article 2005 10.1002/jqs.987 Journal of Quaternary Science 20 655 – 662 7-8 Lake Titicaca; South America; climate variation; Holocene; paleoclimate; paleohydrology; precipitation (climatology) https://www.scopus.com/inward/record.uri?eid=2-s2.0-29744439946&doi=10.1002%2fjqs.987&partnerID=40&md5=9301bd7b00cccb633cacf48a314065a6 Cited by: 79; All Open Access, Green Open Access P.A. Baker S.C. Fritz J. Garland E. Ekdahl article Demory2005167 Sediment cores retrieved from 6 locations in Lake Baikal were subjected to a paleomagnetic study in order to establish detailed age models based on correlations of relative paleointensity records. Additional data were provided by calibrated accelerator mass spectrometry (AMS) 14C dating, as well as by documentation of geomagnetic excursions like Laschamp at ∼42 ka and Iceland Basin at ∼185 ka. Few intervals were affected by diagenetic features like selective reductive dissolution of magnetite and greigite mineralization (Demory et al., 2005-this issue), and those that were left out of paleointensity records. These records were tuned to the well-dated paleomagnetic record from ODP Site 984 Channell [Channell, J.E.T., 1999. Geomagnetic paleointensity and directional secular variation at Ocean Drilling Program (ODP) site 984 (Bjorn Drift) since 500 ka: comparisons with ODP site 983 (Gardar drift). J. Geophys. Res., B: [Solid Earth], 104 (10):22, 937-22, 951]. The complex shape of the resulting depth/age curves highlights the need for a high-resolution age model. We focused on the climatic boundary between marine isotopic stage (MIS) 7 and 6 where the Iceland Basin paleomagnetic excursion is clearly documented in the North Atlantic Channell et al.[Channell, J.E.T., Hodell, D.A., Lehman, B., 1997. Relative geomagnetic paleointensity and d18O at ODP Site 983 (Gardar Drift, North Atlantic) since 350 ka. Earth Planet. Sci. Lett., 153 (1-2), 103-118] and in Lake Baikal Oda et al. [Oda, H., Nakamura, K., Ikehara, K., Nakano, T., Nishimura, M., Khlystov, O., 2002. Paleomagnetic record from Academician Ridge, Lake Baikal: a reversal excursion at the base of marine oxygen isotope stage 6. Earth Planet. Sci. Lett., 202 (1), 117-132] ; present study). During this period, we provide evidence for a return to cold conditions in the Lake Baikal region simultaneous to the sea surface cooling, but earlier than the global ice volume change observed in North Atlantic planktonic and benthic δ18O records, respectively. The classical strategy of age model reconstruction, based on direct correlation of the climatic record from Lake Baikal sediments with the marine δ18O reference curves is shown here to be unreliable. Moreover, this strategy does not consider (i) the nonlinearity of the age model in Lake Baikal sediments and (ii) the time lags between the global ice volume change and sea surface cooling observed in δ18O marine records. Finally, the "Baikal 200" compilation of the paleointensity records established in this study provides a 200-ka-long synthetic paleomagnetic record for Central Eurasia. © 2004 Elsevier B.V. All rights reserved. Conference paper 2005 English 09218181 10.1016/j.gloplacha.2004.09.016 Global and Planetary Change 46 Elsevier B.V. 167 – 186 1-4 SPEC. ISS. Eastern Hemisphere; Eurasia; Lake Baikal; Russian Federation; World; lacustrine deposit; magnetostratigraphy; paleoclimate; paleomagnetism; Quaternary https://www.scopus.com/inward/record.uri?eid=2-s2.0-18044396996&doi=10.1016%2fj.gloplacha.2004.09.016&partnerID=40&md5=f5089be9e9504fe69ab8cb3965a26bd6 Cited by: 52; All Open Access, Green Open Access François Demory Norbert R. Nowaczyk Annette Witt Hedi Oberhänsli article Wilhelm2005357 Boreholes drilled in impact structures are especially suited for investigations of the influence of heterogeneities on petrophysical properties and thermal field. In the scientific well Yaxcopoil-1 drilled within the frame of the International Continental Deep Drilling Program (ICDP) and as a part of the Chicxulub Scientific Drilling Project (CSDP) high resolution temperature measurements and a dense petrophysical profile measured on core samples at ∼2.2 m depth intervals were recorded. From the calculated vertical component of the thermal gradient and the thermal conductivity measured on the core samples a mean heat flow density of 70.5 ± 1.9 mW m-2 in the depth interval 400-1400 m was determined. On the basis of a simple purely conductive heterogeneous 2D thermal model the effect of the refraction of heat caused by heterogeneities is demonstrated. A statistical investigation shows that if the scales of the heterogeneities influencing the values of the measured thermal conductivity and the calculated thermal gradient are small compared to the length of the borehole the effect of the heterogeneities on the vertical heat flow density can be interpreted as thermal noise. © 2005 Nanjing Institute of Geophysical Prospecting. 2005 10.1088/1742-2132/2/4/S09 Journal of Geophysics and Engineering 2 357-363 Geophysical Institute, University of Karlsruhe, Germany; Geophysical Institute, Czech Academy of Sciences, Prague, Czech Republic; Institute of Applied Geosciences, Technical University of Berlin, Germany; Moscow State Geological Prospecting University, Moscow, Russian Federation 4 https://www.scopus.com/inward/record.uri?eid=2-s2.0-28544436762&doi=10.1088%2f1742-2132%2f2%2f4%2fS09&partnerID=40&md5=2c9f6401e13b37d38154247d3683cef7 cited By 9 H. Wilhelm Y. Popov H. Burkhardt J. Šafanda V. Čermák P. Heidinger D. Korobkov R. Romushkevich S. Mayr article Müller2005264 The Bedout High in the Roebuck Basin (formerly offshore Canning Basin) on the northwest shelf of Australia is an unusual structure, which has been controversially interpreted as an end-Permian impact structure similar in size to the K-T boundary Chicxulub Crater. We present a geophysical perspective of the associated debate, based on deep seismic reflection, refraction and well data. The basement and crust in the Roebuck Basin display a number of features that distinguish them from other basins along the northwest Australian margin, including major crustal thinning and the presence of a thick layer of interpreted magmatic underplating. The Bedout High consists of two separate highs separated by a Paleozoic fault, and is associated with a Moho uplift of 7-8 km, and is about 40-50 km wide. The normal fault separating the two highs trends NNW-SSE, roughly paralleling a Paleozoic fault system associated with rifting in the Canning Basin and terminating below the interpreted top-Permian reflection. There are no circular, symmetric fault zones bounding the proposed annular trough, and the distinct difference in seismic character normally associated with impact breccias versus layered sediments above are not expressed in deep multichannel seismic data. The end-Permian horizon exhibits little topography, with well-layered units both below and above. The area around the Bedout High stands out as an area of low velocity basement: 5400-5600 m/s compared to 5800-6000 m/s for other nearby basement areas located in a similar depth range, but known complex impact sites are not characterized by a unique seismic basement velocity signature. Both seismic velocity analysis, revealing a thick underplated layer in the lower crust, and thermal modelling based on data from well La Grange-1 and basalts drilled on top of the Bedout High, are consistent with rifting above anomalously hot mantle. The available geophysical and geological data are compatible with an interpretation of the Bedout structure as a basement high formed by two consecutive Paleozoic and Mesozoic episodes of rifting roughly orthogonal to each other, associated with basin formation east and west of the Bedout High, but fail nearly all unequivocal criteria for impact crater recognition. © 2005 Elsevier B.V. All rights reserved. 2005 10.1016/j.epsl.2005.06.014 Earth and Planetary Science Letters 237 264-284 School of Geosciences, University of Sydney, Institute of Marine Science, Build. F05, Sydney, NSW 2006, Australia; Geoscience Australia, GPO Box 378, Canberra, ACT 2601, Australia; Statoil Research Center, Arkitekt Ebbellsvei 10, Rotvoll N-7005 Trondheim, Norway 1-2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-24144465141&doi=10.1016%2fj.epsl.2005.06.014&partnerID=40&md5=24329e8d1670495819a62d4118ec3e57 cited By 32 R.D. Müller A. Goncharov A. Kritski article Stüben20052559 The investigation of eight Cretaceous-Tertiary (K/T) sections in Mexico, based on major and trace element, platinum group element (PGE), stable isotope, and multivariate statistical analysis, reveals a complex depositional history across the Chicxulub and K/T boundary events. At the biostratigraphically determined K/T boundary, a minor but significant Ir-dominated PGE anomaly (0.2-0.8 ng/g) is present in most sections. This Ir anomaly originated from an impact event and is always stratigraphically and geochemically decoupled from the underlying spherule-rich ejecta deposit related to the Chicxulub event. In all sections examined, one to three glass spherule ejecta layers and one or two chondrite-dominated PGE anomalies are separated by a bioturbated siliciclastic deposit and/or hemipelagic marl, which indicates the occurrence of at least two impact events separated by a considerable amount of time. In addition, bentonite layers and Pt and Pd-dominated PGE anomalies below and above the K/T boundary indicate volcanic activity. Above the K/T boundary, reduced bioproductivity is documented by a decrease in the biogenically bound fraction of nutrients and fluctuating ratios of immobile elements (e.g., Ti/Zr). Variations in detrital elements reflect changes in the depositional environment. Carbon and oxygen isotope and trace element distribution patterns indicate a gradually changing climate during the latest Maastrichtian, an abrupt change at the K/T boundary, and a slight recovery during the lowermost Paleocene. Copyright © 2005 Elsevier Ltd. 2005 10.1016/j.gca.2004.11.003 Geochimica et Cosmochimica Acta 69 2559-2579 Institut für Mineralogie und Geochemie, Universität Karlsruhe, D-76128 Karlsruhe, Germany; Geologisches Institut, Universität Karlsruhe, D-76128 Karlsruhe, Germany; Department of Geosciences, Princeton University, Princeton, NJ 08544, United States 10 https://www.scopus.com/inward/record.uri?eid=2-s2.0-19044393897&doi=10.1016%2fj.gca.2004.11.003&partnerID=40&md5=6ae3f602d60c33ee776f5444b0f92c62 cited By 41 D. Stüben U. Kramar M. Harting W. Stinnesbeck G. Keller article Tuchscherer20051513 We present major and trace element data as well as petrographic observations for impactites (suevitic groundmass, bulk suevite, and melt rock particles) and target lithologies, including Cretaceous anhydrite, dolomite, argillaceous limestone, and oil shale, from the Yaxcopoil-1 borehole, Chixculub impact structure. The suevitic groundmass and bulk suevite have similar compositions, largely representing mixtures of carbonate and silicate components. The latter are dominated by melt rock particles. Trace element data indicate that dolomitic rocks represented a significant target component that became incorporated into the suevites; in contrast, major elements indicate a strong calcitic component in the impactites. The siliceous end-member requires a mafic component in order to explain the low SiO2 content. Multicomponent mixing of various target rocks, the high alteration state, and dilution by carbonate complicate the determination of primary melt particle compositions. However, two overlapping compositional groups can be discerned - a high-Ba, low-Ta group and a high-Fe, high-Zn, and high-Hf group. Cretaceous dolomitic rocks, argillaceous limestone, and shale are typically enriched in U, As, Br, and Sb, whereas anhydrite contains high Sr contents. The oil shale samples have abundances that are similar to the North American Shale Composite (NASC), but with a comparatively high U content. Clastic sedimentary rocks are characterized by relatively high Th, Hf, Zr, As, and Sb abundances. Petrographic observations indicate that the Cretaceous rocks in the Yaxcopoil-1 drill core likely register a multistage deformation history that spans the period from pre- to post-impact. Contrary to previous studies that claimed evidence for the presence of impact melt breccia injection veins, we have found no evidence in our samples from a depth of 1347-1348 m for the presence of melt breccia. We favor that clastic veinlets occur in a sheared and altered zone that underwent intense diagenetic overprint prior to the impact event. © The Meteoritical Society, 2005. 2005 10.1111/j.1945-5100.2005.tb00415.x Meteoritics and Planetary Science 40 1513-1536 Impact Cratering Research Group, School of Geosciences, University of the Witwatersrand, Private Bag 3, P.O. Wits 2050 Johannesburg, South Africa; Department of Geological Sciences, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria 9-10 https://www.scopus.com/inward/record.uri?eid=2-s2.0-29244476876&doi=10.1111%2fj.1945-5100.2005.tb00415.x&partnerID=40&md5=6c1e073f7b9f4f427d1d6626d25aefa0 cited By 22 M.G. Tuchscherer W.U. Reimold C. Koeberl R.L. Gibson article Schorlemmer20051086 2005 English 00280836 10.1038/4341086a Nature 434 1086 Swiss Seismological Service, ETH Zürich, 8093 Zürich, Switzerland 7037 earthquake rupture, article; diagnostic accuracy; earthquake; forecasting; mathematical analysis; prediction; priority journal; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-20844433060&doi=10.1038%2f4341086a&partnerID=40&md5=3990fd47115302e70e8a80387b4145e6 cited By 154 D. Schorlemmer S. Wiemer article Taylor2005 Scientists recently used the drillbit seismic technique to image fractures and shear zones associated with the San Andreas fault near Parkfield, Calif. Low-level energy produced by the drillbit served as a downhole seismic source, and the wave response was measured by an array of geophones at the surface. In the complex structural environment underlying Parkfield, numerous faults that comprise a flower structure are interpreted to cut the Cenozoic sedimentary cover and the Salinian block at the San Andreas Fault Observatory at Depth (SAFOD) project drillsite. Based on updated surface geologic maps by Rymer, these fractures and faults appear to trend subparallel to the San Andreas fault (SAF) and have been mapped up to 3 km to the southwest of the main trace of the SAF. Our study included the interpretation of a surface seismic profile and the drillbit seismic data. These data indicate that faulting is more abundant and shearing more pervasive as one approaches the main trace of the San Andreas fault. In addition, our interpretation of the locations and dips of faults in the PSINE profile correlates very well with locations and dips of several linear features imaged in the migrated drillbit seismic data. 2005 English 00301388 Oil and Gas Journal 103 42-44+46-50 Duke University, Durham, NC, United States; WesternGeco, Houston, TX, United States; Schlumberger-Doll Research, Ridgefield, CT, United States 41 Fracture; Sedimentary rocks; Seismic waves; Seismology; Structural geology; Tectonics, Drillbit seismic technique; Geophones; Surface seismic profile, Seismic prospecting, fracture network; imaging method; San Andreas Fault; seismic method https://www.scopus.com/inward/record.uri?eid=2-s2.0-28144444601&partnerID=40&md5=5432d750490440a598764e7c32bdea94 cited By 0 S.T. Taylor C. Stolte J.B.U. Haldorsen R. Coates P. Malin E. Shalev article Šafanda2005326 Temperature-depth profiles, obtained during three campaigns of temperature logging in boreholes of the Yucatán Peninsula in the period 2002-2004, display the effects of thermal fluid convection. These effects are most pronounced in the uppermost part of the 1.5 km deep borehole Yaxcopoil-1 drilled within the Chicxulub impact crater. The convective zone is clearly discernible in all three profiles measured here in March 2002, May 2003 and February 2004. The loggings have revealed a gradual downward propagation of the convective features from the uppermost 145 m of the temperature profile to 230 m between the first and second loggings (with a propagation rate of 6 m/month) and to 265 m between the second and third loggings (4 m/month). A signature of the fluid convection is also evident in all other temperature logs in the area measured during the 2003 campaign, namely in four UNAM boreholes 2, 5, 7 and 8, three hydrogeological boreholes 1A, 1B and 1C, in a borehole at the meteorological observatory Mérida and in the cenote Ucil. The fresh/salt water interface is clearly visible in most of the logs as a zone of increased temperature gradient. The varying intensity of the convective features among the individual logs seems to be correlated with the borehole position relative to the impact structure. © 2005 Nanjing Institute of Geophysical Prospecting. 2005 10.1088/1742-2132/2/4/S05 Journal of Geophysics and Engineering 2 326-331 Geophysical Institute, Prague, Czech Republic; Geophysical Institute, University Karlsruhe, Germany 4 https://www.scopus.com/inward/record.uri?eid=2-s2.0-28544435362&doi=10.1088%2f1742-2132%2f2%2f4%2fS05&partnerID=40&md5=92d41f931876a8d41e21ae1dc394cf41 cited By 12 J. Šafanda P. Heidinger H. Wilhelm V. Čermák article Takahashi200599 At Mallik of the Mackenzie Delta in the Arctic Canada, over a 79 day period, from December 25, 2001 to March 14, 2002, three (3) wells were drilled through the hydrate formation beneath permafrost on a line at 40m distance, where coring, logging, various science experiments and production testing were performed. This research project was organized and funded by participants from five (5) countries of Japan, Canada, US, Germany and India. Japan National Oil Corporation (JNOC) and Japan Petroleum Exploration Co. Ltd. (JAPEX) undertook its operation while the Geological Survey of Canada (GSC) coordinated the science program. This paper describes the drilling operation including its logistics of the Mallik 2002 Gas Hydrate Production Research Well Program. 2005 Japanese 09168753 Nihon Enerugi Gakkaishi/Journal of the Japan Institute of Energy 84 99-105 Japan Petroleum Exploration Co., Ltd., 2-2-20 Higashi-shinagawa, Shinagawa, Tokyo 140-0002, Japan 2 Crude petroleum; Logistics; Natural gas well drilling; Project management; Societies and institutions, Arctic operations; Geological Survey of Canada (GSC); Japan National Oil Corporation (JNOC); Remote operations, Gas hydrates https://www.scopus.com/inward/record.uri?eid=2-s2.0-19944363184&partnerID=40&md5=b40434c0f86f87472bd44f2992d87bf7 cited By 0 H. Takahashi article Špičák200544 2005 English 18168957 10.5194/sd-1-44-2005 Scientific Drilling 1 Copernicus GmbH 44-45 Geophysical Institute of the Academy of Sciences of the Czech Republic, Bocni II/1401 14131, Prague 4, Czech Republic; GeoForschungsZentrum Potsdam, Telegrafenberg, Potsdam, 14473, Germany Energy resources; Mechanical engineering, Drilling https://www.scopus.com/inward/record.uri?eid=2-s2.0-57649207115&doi=10.5194%2fsd-1-44-2005&partnerID=40&md5=d1a19e7add4f9d8bab45a03a71d0cc73 cited By 6 A. Špičák A. Förster B. Horsfield conference Calvin2005565 Infrared spectroscopy has been used to identify rocks and minerals for over 40 years. The technique is sensitive to primary silicates as well as alteration products. Minerals can be uniquely identified based on multiple absorption features at wavelengths from the visible to the thermal infrared. We are currently establishing methods and protocols in order to use the technique for rapid assessment of downhole lithology on samples obtained during drilling operations. Initial work performed includes spectral analysis of chip cuttings and core sections from drill sites around Desert Peak, NV. In this paper, we report on a survey of 10,000 feet of drill cuttings, at 100 foot intervals, from the San Andreas Fault Observatory at Depth (SAFOD). Data from Blue Mountain geothermal wells will also be acquired. We will describe the utility of the technique for rapid assessment of lithologic and mineralogic discrimination. 2005 English 01935933 Transactions - Geothermal Resources Council 29 565-568 Geological Sciences, Great Basin Center for Geothermal Research, University of Nevada - Reno, Reno, NV, United States; U. S. Geological Survey, Earthquake Hazards Team, Menlo Park, CA, United States Geothermal wells; Infrared spectroscopy; Lithology; Silicates; Spectrum analysis; Well drilling, Chip cuttings; Drill hole logging; San Andreas Fault Observatory at Depth (SAFOD); Spectroscopy mineralogy, Well logging https://www.scopus.com/inward/record.uri?eid=2-s2.0-33745190500&partnerID=40&md5=ae639a0a3dc6fb3d154b8ef7e6f166bc cited By 4 W.M. Calvin J.G. Solum article Poag2005117 This study reexamines seven reprocessed (increased vertical exaggeration) seismic reflection profiles that cross the eastern rim of the Chesapeake Bay impact crater. The eastern rim is expressed as an arcuate ridge that borders the crater in a fashion typical of the "raised" rim documented in many well preserved complex impact craters. The inner boundary of the eastern rim (rim wall) is formed by a series of raterfacing, steep scarps, 15-60 m high. In combination, these rim-wall scarps represent the footwalls of a system of crater-encircling normal faults, which are downthrown toward the crater. Outboard of the rim wall are several additional normal-fault blocks, whose bounding faults trend approximately parallel to the rim wall. The tops of the outboard fault blocks form two distinct, parallel, flat or gently sloping, terraces. The innermost terrace (Terrace 1) can be identified on each profile, but Terrace 2 is only sporadically present. The terraced fault blocks are composed mainly of nonmarine, poorly to moderately consolidated, siliciclastic sediments, belonging to the Lower Cretaceous Potomac Formation. Though the ridge-forming geometry of the eastern rim gives the appearance of a raised compressional feature, no compelling evidence of compressive forces is evident in the profiles studied. The structural mode, instead, is that of extension, with the clear dominance of normal faulting as the extensional mechanism. © 2005 Geological Society of America. 2005 English 00721077 10.1130/0-8137-2384-1.117 Special Paper of the Geological Society of America 384 Geological Society of America 117-130 U.S. Geological Survey, 384 Woods Hole Road, Woods Hole, MA 02543-1598, United States Meteor impacts; Morphology; Stratigraphy; Structure (composition), Chesapeake Bay; Compressive forces; Impact craters; Lower Cretaceous; Normal faulting; Seismic reflection profiles; Siliciclastic sediments; Structural modes, Fault slips, crater; Cretaceous; dominance; faulting; morphology; seismic reflection; stratigraphy; terrace, Chesapeake Bay; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-73949150401&doi=10.1130%2f0-8137-2384-1.117&partnerID=40&md5=16c16e40d40a07acb7893db2f8163536 cited By 8 C.W. Poag article Bräuer20051 We present new 3He/4He data of CO2-rich gas exhalations of three presently nonvolcanic areas in Europe. The 3He/4He ratios from the Cheb basin (Czech Republic) are clearly higher than data obtained ten years ago, whereas the 3He/4He ratios from the other areas (Laacher See/Germany and Mariánské Lázně/CR) have remained nearly constant. No other locality showing such high 3He/4He ratios in free gases supplied by continental mantle degassing is known in the European Cenozoic rift system. At the northeastern edge of the Cheb basin swarm earthquakes repeatedly occur. In the context of contemporaneous periods of seismicity the increased 3He/4He ratios are interpreted as the first geochemical evidence for ascending mantle-derived melt beneath the Cheb basin, which is related to the triggering of earthquake swarms. Copyright 2005 by the American Geophysical Union. Article 2005 English 00948276 10.1029/2004GL022205 Geophysical Research Letters 32 American Geophysical Union 1 – 4 8 Central Europe; Cheb Basin; Czech Republic; Eastern Hemisphere; Eurasia; Europe; World; Catchments; Degassing; Earthquakes; Helium; Europe; Mantle; Nonvolcanic areas; Rifts; mantle plume; Geophysics https://www.scopus.com/inward/record.uri?eid=2-s2.0-22944484430&doi=10.1029%2f2004GL022205&partnerID=40&md5=0c1993ec7c6739d8e67323bf678690fc Cited by: 62 Karin Bräuer Horst Kämpf Samuel Niedermann Gerhard Strauch article Holtz2005319 Crystallization experiments were conducted on dry glasses from the Unzen 1992 dacite at 100 300 MPa, 775-875°C, various water activities, and fO2 buffered by the Ni-NiO buffer. The compositions of the experimental products and natural phases are used to constrain the temperature and water contents of the low-temperature and high-temperature magmas prior to the magma mixing event leading to the 1991-1995 eruption. A temperature of 1050 ± 75°C is determined for the high-temperature magma based on two-pyroxene thermometry. The investigation of glass inclusions suggests that the water content of the rhyolitic low-temperature magma could be as high as 8 wt % H2O. The phase relations at 300 MPa and in the temperature range 870-900°C, which are conditions assumed to be representative of the main magma chamber after mixing, show that the main phenocrysts (orthopyroxene, plagioclase, hornblende) coexist only at reduced water activity; the water content of the post-mixing dacitic melt is estimated to be 6 ± 1 wt % H2O. Quartz and biotite, also present as phenocrysts in the dacite, are observed only at low temperature (below 800-775°C). It is concluded that the erupted dacitic magma resulted from the mixing of c. 35 wt % of an almost aphyric pyroxene-bearing andesitic magma (1050 ± 75°C; 4 ± 1 wt % H2O in the melt) with 65 wt % of a phenocryst-rich low-temperature magma (760-780°C) in which the melt phase was rhyolitic, containing up to 8 ± 1 wt % H2O. The proportions of rhyolitic melt and phenocrysts in the low-temperature magma are estimated to be 65% and 35%, respectively. It is emphasized that the strong variations of phenocryst compositions, especially plagioclase, can be explained only if there were variations of temperature and /or water activity (in time and/or space) in the low-temperature magma. © Oxford University Press; all rights reserved. Article 2005 English 00223530 10.1093/petrology/egh077 Journal of Petrology 46 319 – 337 2 Asia; Eastern Hemisphere; Eurasia; Far East; Japan; Kyushu; Nagasaki [Kyushu]; Unzen Volcano; World; dacite; magma chemistry; petrology; volcanic rock https://www.scopus.com/inward/record.uri?eid=2-s2.0-13344259964&doi=10.1093%2fpetrology%2fegh077&partnerID=40&md5=2202f170708ef9f84f90fbef82e75543 Cited by: 129; All Open Access, Bronze Open Access François Holtz Hiroaki Sato Jared Lewis Harald Behrens Setsuya Nakada article Sato2005339 High-temperature-pressure experiments were carried out to determine the chlorine-hydroxyl exchange partition coefficient between hornblende and melt in the 1992 Unzen dacite. Cl in hornblende and melt was analyzed by electron microprobe, whereas OH in hornblende and melt was calculated assuming anion stoichiometry of hornblende and utilizing the dissociation reaction constant for H2O + O = 2(OH) in water-saturated melt, respectively. The partition coefficient strongly depends on the Mg/(Mg + Fe) ratio of hornblende, and is expressed as In K1 = (Cl/OH)hb/(Cl/OH)melt = 2· 37 - 4·6[Mg/(Mg + Fe)]hb at 2-3kbar and 800-850°C. The twofold variation in Cl content in the oscillatory zoned cores of hornblende phenocrysts in the 1991-1995 dacite cannot be explained by the dependence of the Cl/OH partition coefficient on the Mg/(Mg + Fe) hb ratio, and requires c. 80% variation of the Cl/OH ratio of the coexisting melt. Available experimental data at 200 MPa on Cl/OH fractionation between fluid and melt suggest that c. 1· 2-1·8 wt % degassing of water from the magma can explain the required 80% variation in the Cl/OH ratio of the melt. The negative correlation between Al content and Mg/(Mg + Fe) ratio in the oscillatory zoned cores of the hornblende phenocrysts is consistent with repeated influx and convective degassing of the fluid phase in the magma chamber. © Oxford University Press 2004; All rights reserved. Article 2005 English 00223530 10.1093/petrology/egh078 Journal of Petrology 46 339 – 354 2 Asia; Eastern Hemisphere; Eurasia; Far East; Japan; Kyushu; Nagasaki [Kyushu]; Unzen Volcano; World; dacite; magma chemistry; petrology; volcanic rock https://www.scopus.com/inward/record.uri?eid=2-s2.0-13344285318&doi=10.1093%2fpetrology%2fegh078&partnerID=40&md5=9bc0a3728bae5dba836b69b79f9b863f Cited by: 70; All Open Access, Bronze Open Access, Green Open Access Hiroaki Sato François Holtz Harald Behrens Roman Botcharnikov Setsuya Nakada article Takahashi200453 The first production test of methanehydrate layers was carried out in the Mackenzie Delta in the Canadian Arctic. Three wells were drilled through hydrate layers at a depth of approximately 900 to 1100 m beneath 640 m of permafrost on a line at 40-m spacing. Coring, logging, and other scientific experiments and production test were performed over a 79-day period. The Geologic Survey of Canada (GSC) was coordinator of the science program, and Japan Natl. Oil Corp. (JNOC) and Japan Petroleum Exploration Co. (JAPEX) were operators. 2004 English 01492136 JPT, Journal of Petroleum Technology 56 53-54 Japan Petroleum Exploration Co. Ltd., Japan; Japan Natl. Oil Corp., Japan; Canadian Petroleum Engineering Inc., Canada 4 Coring; Gas hydrate production; Hole enlargement; Openhole well logs, Core samples; Methane; Natural gas well drilling; Natural gas well logging; Natural gas well production; Permafrost, Gas hydrates https://www.scopus.com/inward/record.uri?eid=2-s2.0-1842832851&partnerID=40&md5=999c45123e42c6a26c983a4aa2ce21d4 cited By 4 H. Takahashi T. Yonezawa E. Fercho article Giurgea2004467 The AIG10 borehole provided direct access to hydraulic conditions. The first results of two open-hole pumping tests and one artesian production test are presented. From the first pumping test in the conglomerates, a hydraulic conductivity of 10-5-10-4 ms-1 was derived and it was suggested that there is a closed hydraulic system bounded by the Aigion Fault zone and other faults farther north. A second pumping test, in the Olonos-Pindos limestones, showed artesian flow (water pressure of 0.5 MPa and flow of 1.9×10-4 m3s-1). The transmissivity is about 4×10-6 m2s-1. Below the fault zone, pressure and flux increased, suggesting karstic water-flow conditions. Water-pressure difference of more than 0.5 MPa between the hangingwall and the footwall provides evidence that the Aigion Fault zone acts as an impervious zone. An artesian production test for the interval 708-1001 m showed a fluid pressure of >1 MPa and natural flow of 1.5×10-2 m3s-1. A transmissivity of 2-3 ×10-4 m2s-1 was determined. A preliminary conceptual hydrogeological model, containing flow parameters and flow paths, is developed, based on data from AIG10 and other wells and springs. © 2004 Académie des sciences. Published by Elsevier SAS. All rights reserved. Article 2004 French 16310713 10.1016/j.crte.2003.12.012 Comptes Rendus - Geoscience 336 467 – 475 4-5 Gulf of Corinth; Ionian Sea; Mediterranean Sea; borehole logging; fault; hydraulic property; hydrogeology; rift zone; transmissivity https://www.scopus.com/inward/record.uri?eid=2-s2.0-1942505385&doi=10.1016%2fj.crte.2003.12.012&partnerID=40&md5=7f18d5befea7c6ffef1c01866a645370 Cited by: 25 Vlad Giurgea Detlev Rettenmaier Luca Pizzino Ingmar Unkel Heinz Hötzl Andrea Förster Fedora Quattrocchi article Naville2004407 Pre-drill reflection surface seismic was carried out in the Aigion city area in February 2001. The poor quality of seismic reflections obtained from standard processing did not allow us to refine the location of the vertical well AIG-10 to be drilled. Subsequently, a brief study of refracted seismic arrivals was attempted in order to better define the well location, in conjunction with observations from a shallow well. In 2002, after drilling, an innovative 6-VSP position well seismic survey was successfully run, using a four-component downhole sensor tool, i.e., three orthogonal geophones and a hydrophone. Refracted seismic events and first arrivals from VSP indicated the throw of the Aigion Fault and the fault plane dip; a secondary accident striking about south-north was detected about 100 m west of the well. No P-P seismic reflection was evidenced from standard VSP processing. © 2004 Académie des sciences. Published by Elsevier SAS. All rights reserved. Article 2004 English 16310713 10.1016/j.crte.2003.12.010 Comptes Rendus - Geoscience 336 407 – 414 4-5 Gulf of Corinth; Ionian Sea; Mediterranean Sea; borehole; fault; rift zone; seismic survey https://www.scopus.com/inward/record.uri?eid=2-s2.0-1942473542&doi=10.1016%2fj.crte.2003.12.010&partnerID=40&md5=9b398018aa9654e58cd7e3096d2875ee Cited by: 14 Charles Naville Sylvain Serbutoviez Isabelle Moretti Jean-Marc Daniel Alexandre Throo François Girard Andreas Sotiriou Akis Tselentis Christos Skarpzelos Christophe Brunet François Cornet article Tagle20041009 This study presents results of platinum group element (PGE) analyses of impactites from the Yaxcopoil-1 (Yax- 1) and Yucatán 6 drill cores of the 180 km-diameter Chicxulub crater. These are the main elements used for projectile identification. They were determined by nickel sulfide fire assay combined with inductively coupled plasma mass spectrometry. The concentration of PGE in the samples are low. The concentration patterns of the suevite samples resemble the pattern of the continental crust. We conclude that any meteoritic fraction in these samples is below 0.05%. A synand post-impact modification of the PGE pattern from meteoritic toward a continental crust pattern is very unlikely. The globally distributed fallout at the Cretaceous-Tertiary (K/T) boundary, however, has high PGE concentrations. Therefore, the lack of a significant meteoritic PGE signature in the crater is not an argument for a PGE-poor impactor. Taking the results of three-dimensional numerical simulations of the Chicxulub event into account, the following conclusions are drawn: 1) The main fraction of the impactor was ejected into and beyond the stratosphere, distributed globally, and deposited in the K/T boundary clay; and 2) the low amount of projectile contamination in the Yax-1 lithologies may reflect an oblique impact. However, the role of volatiles in the mixing process between projectile and target is not well-understood and may also have played a fundamental role. 2004 10.1111/j.1945-5100.2004.tb00942.x Meteoritics and Planetary Science 39 1009-1016 Institut für Mineralogie, Museum für Naturkunde, Humboldt-Universität zu Berlin, Invalidenstrasse 43, Berlin D-10099, Germany; GFZ-Potsdam, Potsdam 14473, Germany; Vrije Universiteit Brussel, Pleinlaan 2, Brussels B-1050, Belgium 6 https://www.scopus.com/inward/record.uri?eid=2-s2.0-3943057392&doi=10.1111%2fj.1945-5100.2004.tb00942.x&partnerID=40&md5=e45a383e937de5e76e83564650ff0335 cited By 25 R. Tagle J. Erzinger L. Hecht R.T. Schmitt D. Stöffler P. Claeys article Popov2004799 Physical properties were determined in a first step on post-impact tertiary limestones from the depth interval of 404-666 m of the Yaxcopoil-1 (Yax-1) scientific well, drilled in the Chicxulub impact crater (Mexico). Thermal conductivity, thermal diffusivity, density, and porosity were measured on 120 dry and water-saturated rocks with a core sampling interval of 2-2.5 m. Non-destructive, non-contact optical scanning technology was used for thermal property measurements including thermal anisotropy and inhomogeneity. Supplementary petrophysical properties (acoustic velocities, formation resisitivity factor, internal surface, and hydraulic permeability) were determined on a selected subgroup of representative samples to derive correlations with the densely measured parameters, establishing estimated depth logs to provide calibration values for the interpretation of geophysical data. Significant short- and long-scale variations of porosity (1-37%) turned out to be the dominant factor influencing thermal, acoustic, and hydraulic properties of this post impact limestone formation. Correspondingly, large variations of thermal conductivity, thermal diffusivity, acoustic velocities, and hydraulic permeability were found. These variations of physical properties allow us to subdivide the formation into several zones. A combination of experimental data on thermal conductivity for dry and water-saturated rocks and a theoretical model of effective thermal conductivity for heterogeneous media have been used to calculate thermal conductivity of mineral skeleton and pore aspect ratio for every core under study. The results on thermal parameters are the necessary basis for the determination of heat flow density, demonstrating the necessity of dense sampling in the case of inhomogeneous rock formations. © Meteoritical Society, 2004. 2004 10.1111/j.1945-5100.2004.tb00930.x Meteoritics and Planetary Science 39 799-812 Moscow State Geol. Prospecting Univ., Moscow, Russian Federation; Department of Applied Geosciences, Technical University, Berlin, Germany; Geophysical Institute, University Karlsruhe, Karlsruhe 76131, Germany 6 https://www.scopus.com/inward/record.uri?eid=2-s2.0-3943074395&doi=10.1111%2fj.1945-5100.2004.tb00930.x&partnerID=40&md5=8969428d578c8eb9dab2d97768c0629e cited By 23 Y. Popov R. Romushkevich I. Bayuk D. Korobkov S. Mayr H. Burkhardt H. Wilhelm article Winters20041221 This paper presents results of shear strength and acoustic velocity (p-wave) measurements performed on: (1) samples containing natural gas hydrate from the Mallik 2L-38 well, Mackenzie Delta, Northwest Territories; (2) reconstituted Ottawa sand samples containing methane gas hydrate formed in the laboratory; and (3) ice-bearing sands. These measurements show that hydrate increases shear strength and p-wave velocity in natural and reconstituted samples. The proportion of this increase depends on (1) the amount and distribution of hydrate present, (2) differences, in sediment properties, and (3) differences in test conditions. Stress-strain curves from the Mallik samples suggest that natural gas hydrate does not cement sediment grains. However, stress-strain curves from the Ottawa sand (containing laboratory-formed gas hydrate) do imply cementation is present. Acoustically, rock physics modeling shows that gas hydrate does not cement grains of natural Mackenzie Delta sediment. Natural gas hydrates are best modeled as part of the sediment frame. This finding is in contrast with direct observations and results of Ottawa sand containing laboratory-formed hydrate, which was found to cement grains (Waite et al. 2004). It therefore appears that the microscopic distribution of gas hydrates in sediment, and hence the effect of gas hydrate on sediment physical properties, differs between natural deposits and laboratory-formed samples. This difference may possibly be caused by the location of water molecules that are available to form hydrate. Models that use laboratory-derived properties to predict behavior of natural gas hydrate must account for these differences. 2004 English 0003004X 10.2138/am-2004-8-909 American Mineralogist 89 Mineralogical Society of America 1221-1227 U.S. Geological Survey, 384 Woods Hole Road, Woods Hole, MA 02543, United States; Inst. of Geological/Nuclear Science, 69 Gracefield Road, Lower Hutt, New Zealand 8-9 Acoustic wave velocity; Cements; Gases; Hydration; Laboratories; Methane; Molecules; Natural gas; Natural gas wells; Physical properties; Sand; Sediments; Seismic waves; Shear flow; Stress-strain curves; Wave propagation, Derived properties; Direct observations; Methane gas hydrates; Microscopic distribution; P-wave velocity; Reconstituted sample; Rock physics model; Sediment properties, Gas hydrates, acoustic property; clathrate; gas hydrate; methane; sediment property; shear strength; water content https://www.scopus.com/inward/record.uri?eid=2-s2.0-4444244874&doi=10.2138%2fam-2004-8-909&partnerID=40&md5=b05feae13d230988a79be90127c3b35c cited By 204 W.J. Winters I.A. Pecher W.F. Waite D.H. Mason article Solum2004 This paper establishes a reference phyllosilicate data set from the SAFOD Pilot Hole for future SAFOD drilling and presents an application of these data for studies of exhumed fault segments. The chlorite assemblages in cuttings from two intervals of the SAFOD Pilot Hole are separated into two populations based on X-ray diffraction characteristics. The first population is found in granite in both the deeper and shallower interval, whereas the second population occurs only in clastic sedimentary rocks in the shallower interval. The characteristics of the first population match those for protolith and cataclasite of the exhumed Punchbowl Fault, whereas samples from intensely deformed ultracataclasite are most similar to the second. This supports previous findings that the mineral assemblages in the ultracataclasite formed after the cessation of motion along the fault, above a depth of ∼2 km, and that mineral assemblages in these exhumed fault rocks have been overprinted by post-faulting alteration. Copyright 2004 by the American Geophysical Union. 2004 English 00948276 10.1029/2004GL019909 Geophysical Research Letters 31 L15S19 1-4 Department of Geological Sciences, University of Michigan, 425 E. University Ave., Ann Arbor, MI 48109-1063, United States 15 Boreholes; Drilling; Geophysical prospecting; Granite; Sedimentary rocks; X ray diffraction analysis, Fault rocks; Mineral assemblages; Pilot holes, Silicate minerals, borehole geophysics; cataclasite; fault slip; mineralogy; phyllosilicate; San Andreas Fault https://www.scopus.com/inward/record.uri?eid=2-s2.0-7044249760&doi=10.1029%2f2004GL019909&partnerID=40&md5=97a0d5a5fd4f43d07b7790061f0bbe76 cited By 21 J.G. Solum B.A. Pluijm article Urrutia-Fucugauchi2004843 Results of a detailed paleomagnetic and rock magnetic study of samples of the impact breccia sequence cored in the Yaxcopoil-1 (Yax-1) borehole between about 800 m and 896 m are presented. The Yax-1 breccia sequence occurs from 794.63 m to 894.94 m and consists of redeposited melt-rich, clast-size sorted, fine-grained suevites; melt-rich, no clast-size sorting, medium-grained suevites; coarse suevitic melt agglomerates; coarse melt-rich heterogeneous suevites; brecciated suevites; and coarse carbonate and silicate melt suevites. The low-field susceptibility ranges from -0.3 to 4018 × 10-6 SI, and the NRM intensity ranges from 0.02 mA/m up to 37510 mA/m. In general, the NRM intensity and magnetic susceptibility present wide ranges and are positively correlated, pointing to varying magnetic mineral contents and textures of the melt-rich breccia sequence. The vectorial composition and magnetic stability of NRM were investigated by both stepwise alternating field and thermal demagnetization. In most cases, characteristic single component magnetizations are observed. Both upward and downward inclinations are present through the sequence, and we interpret the reverse magnetization as the primary component in the breccias. Both the clasts and matrix forming the breccia appear to have been subjected to a wide range of temperature/pressure conditions and show distinct rock magnetic properties. An extended interval of remanence acquisition and secondary partial or total remagnetization may explain the paleomagnetic results. © Meteoritical Society, 2004. 2004 10.1111/j.1945-5100.2004.tb00934.x Meteoritics and Planetary Science 39 843-856 Lab. Paleomagnetismo/Geofisica Nucl., Instituto de Geofisica, Univ. Nacional Autonoma Mexico, Coyoacán, Mexico DF 04510, Mexico 6 https://www.scopus.com/inward/record.uri?eid=2-s2.0-3943096576&doi=10.1111%2fj.1945-5100.2004.tb00934.x&partnerID=40&md5=71170e86e0804b5a95a0615973b701dd cited By 16 J. Urrutia-Fucugauchi A.M. Soler-Arechalde M. Rebolledo-Vieyra P. Vera-Sanchez article Kurz2004 This paper presents new magmatic helium isotopic compositions in a suite of lavas from phase II of the Hawaiian Scientific Drilling Project (HSDP2) core, which sampled Mauna Kea volcano to a maximum depth of 3098 m below sea level. Most of the measurements were performed by in vacuo crushing of olivine phenocrysts, but include submarine pillow glasses from the 2200 to 2500 meter depth interval, and orthopyroxene phenocrysts from an intrusive at 1880 m. The magmatic 3He/4He ratios range from 6 to 24.7 times atmospheric (Ra), which significantly extends the range of values for Mauna Kea volcano. The 3He/4He ratios are lowest (i.e., close to MORB values of ∼8 Ra) near the top of the Mauna Kea section and rise slowly, to 10-12 Ra, at 1000 m below sea level, consistent with results from the HSDP1 core. At depths greater than 1000 m in the core, primarily in the submarine lavas, there are brief periods when the 3He/4He ratios are higher than 14.5 Ra, always returning to a baseline value. Twelve such excursions were identified in the core; all but one are in the submarine section, and most (7) are in the deepest section, at depths of 1950 to 3070 m. The baseline 3He/4He value rises from 10-12 Ra near 1000 m depth to 12-14 Ra at 3000 m. The helium spikes are found only in lavas that are older than 380 Ka in age, based on an age model derived from Ar-Ar data (W. D. Sharp et al., manuscript in preparation, 2003). Excluding the excursions defined by single lava flows (3) and intrusive units (3), the average spike duration is approximately 15 (±9) Ka (n = 6). The high 3He/4He spikes are interpreted as pulses of magma from the center of the actively upwelling Hawaiian hot spot. The short duration of the high 3He/4He excursions suggests that Mauna Kea was never directly over high the 3He/4He component of the plume (during the HSDP2 eruptive period), presumed to be the plume center. Assuming that the Mauna Kea helium spikes result from melting of heterogeneities within the plume, their short duration implies that the length scales of heterogeneities in the solid upwelling mantle are between 60 m and 12 km (for upwelling rates of 2 to 40 cm/yr). The high 3He/4He are associated with high 208Pb/204Pb, and relatively low 143Nd/144Nd, Zr/Nb, and SiO2. The correlations with major elements, trace elements and isotopes demonstrate that helium is coupled to the other geochemical variations, and that the Mauna Kea isotopic variability is caused by heterogeneities within the upwelling plume. Copyright 2004 by the American Geophysical Union. Article 2004 English 15252027 10.1029/2002GC000439 Geochemistry, Geophysics, Geosystems 5 4 https://www.scopus.com/inward/record.uri?eid=2-s2.0-16844379937&doi=10.1029%2f2002GC000439&partnerID=40&md5=f51cb57bcea6fb8eec35000eb297146c Cited by: 104; All Open Access, Green Open Access Mark D. Kurz Joshua Curtice Dempsey E. Lott III Andy Solow article Pilkington2004831 Core from the Yaxcopoil-1 (Yax-1) hole, drilled as a result of the Chicxulub Scientific Drilling Project (CSDP), has been analyzed to investigate the relationship between opaque mineralogy and rock magnetic properties. Twenty one samples of suevite recovered from the depth range 818-894 m are generally paramagnetic, with an average susceptibility of 2000 × 10-6 SI and have weak remanent magnetization intensities (average 0.1 A/m). The predominant magnetic phase is secondary magnetite formed as a result of low temperature (&lt;15 °C alteration. It occurs in a variety of forms, including vesicle infillings associated with quartz and clay minerals and fine aggregates between plagioclase/diopside laths in the melt. Exceptional magnetic properties are found in a basement clast (metamorphosed quartz gabbro), which has a susceptibility of &gt;45000 × 10-6 SI and a remanent magnetization of 77.5 A/m. Magnetic mafic basement clasts are a common component in the Yax-1 impactite sequence. The high susceptibility and remanence in the mafic basement clasts are caused by the replacement of amphiboles and pyroxenes by an assemblage with fine &lt;1 μm magnetite, ilmenite, K-feldspar, and stilpnomelane. Replacement of the mafic minerals by the magnetic alteration assemblage occurred before impact. Similar alteration mechanisms, if operative within the melt sheet, could explain the presence of the high amplitude magnetic anomalies observed at Chicxulub. © Meteoritical Society, 2004. 2004 10.1111/j.1945-5100.2004.tb00933.x Meteoritics and Planetary Science 39 831-841 Geological Survey of Canada, 615 Booth Street, Ottawa, Ont. K1A 0E9, Canada; Department of Geology and Geophysics, University of Calgary, 2500 University Drive NW, Calgary, AB T2N 1N4, Canada 6 https://www.scopus.com/inward/record.uri?eid=2-s2.0-3943108811&doi=10.1111%2fj.1945-5100.2004.tb00933.x&partnerID=40&md5=cf6a4f603ed2a7e5186c40995ae0ac2d cited By 14 M. Pilkington D.E. Ames A.R. Hildebrand article Gelinas20041003 The spatial distribution and amount of material transferred from the bolide involved in the Cretaceous/Tertiary (K/T) event to the target rocks at Chicxulub is still poorly constrained. In this study, Re-Os isotopic analyses of impact melt breccias and lithic clasts from the Yaxcopoil-1 (Yax- 1) borehole were used to determine the distribution and proportion of the bolide component in the target rocks. Because of the much greater concentration of Os in chondritic meteorites compared to the target rocks, little addition of the bolide component would be necessary to greatly perturb the Os concentration and isotopic composition of target rocks. Hence, this is a very sensitive means of examining bolide contributions to the target rocks. For the examined suite of samples, the initial 187OS/188Os ratios vary from 0.19 to 2.3. Conservative mixing calculations suggest that the bolide component comprised as much as approximately 0.1%, by mass, of some samples. Most samples, however, have negligible contributions from the bolide. No samples have Os that is dominated by the bolide component, so for this suite of samples, it is impossible to fingerprint the chemical nature of the bolide using relative abundances of siderophile elements. These results suggest that the bolide did not contribute a significant amount of material to the target rocks. This may, in turn, indicate that most of the bolide was vaporized upon impact or otherwise ejected without mixing with the melt from the target. 2004 10.1111/j.1945-5100.2004.tb00941.x Meteoritics and Planetary Science 39 1003-1008 Isotope Geochemistry Laboratory, Department of Geology, University of Maryland, College Park, MD 20742, United States; Lunar and Planetary Laboratory, University of Arizona, 1629 East University Boulevard, Tucson, AZ 85721, United States; Instituto de Geofísica, Univ. Nacl. Autonoma de Mexico, Coyoacán, D.F. 04510, Mexico 6 https://www.scopus.com/inward/record.uri?eid=2-s2.0-3943066309&doi=10.1111%2fj.1945-5100.2004.tb00941.x&partnerID=40&md5=99fc1ecc30e8782924fdef1c77113b95 cited By 28 A. Gelinas D.A. Kring L. Zurcher J. Urrutia-Fucugauchi O. Morton article Stöffler20041035 We present and interpret results of petrographic, mineralogical, and chemical analyses of the 1511 in deep ICDP Yaxcopoil-1 (Yax-1 ) drill core, with special emphasis on the impactite units. Using numerical model calculations of the formation, excavation, and dynamic modification of the Chicxulub crater, constrained by laboratory data, a model of the origin and emplacement of the impact formations of Yax-1 and of the impact structure as a whole is derived. The lower part of Yax-1 is formed by displaced Cretaceous target rocks (610 m thick), while the upper part comprises six suevite-type allochthonous breccia units (100 m thick). From the texture and composition of these lithological units and from numerical model calculations, we were able to link the seven distinct impact-induced units of Yax-1 to the corresponding successive phases of the crater formation and modification, which are as follows: 1) transient cavity formation including displacement and deposition of Cretaceous "megablocks;" 2) ground surging and mixing of impact melt and lithic clasts at the base of the ejecta curtain and deposition of the lower suevite right after the formation of the transient cavity; 3) deposition of a thin veneer of melt on top of the lower suevite and lateral transport and brecciation of this melt toward the end of the collapse of the transient cavity (brecciated impact melt rock); 4) collapse of the ejecta plume and deposition of fall-back material from the lower part of the ejecta plume to form the middle suevite near the end of the dynamic crater modification; 5) continued collapse of the ejecta plume and deposition of the upper suevite; 6) late phase of the collapse and deposition of the lower sorted suevite after interaction with the inward flowing atmosphere; 7) final phase of fall-back from the highest part of the ejecta plume and settling of melt and solid particles through the reestablished atmosphere to form the upper sorted suevite; and 8) return of the ocean into the crater after some time and minor reworking of the uppermost suevite under aquatic conditions. Our results are compatible with: a) 180 km and 100 km for the diameters of the final crater and the transient cavity of Chicxulub, respectively, as previously proposed by several authors, and b) the interpretation of Chicxulub as a peak-ring impact basin that is at transition to a multi-ring basin. © Meteoritical Society, 2004. 2004 10.1111/j.1945-5100.2004.tb01128.x Meteoritics and Planetary Science 39 1035-1067 Institut für Mineralogie, Museum fur Naturkunde, Humboldt-Universität zu Berlin, Invalidenstrasse 43, Berlin D-10099, Germany; Institute for Dynamics of Geospheres, Leninsky Prospect 38, Moscow 119334, Russian Federation 7 https://www.scopus.com/inward/record.uri?eid=2-s2.0-3943110343&doi=10.1111%2fj.1945-5100.2004.tb01128.x&partnerID=40&md5=b19e7ace1845c286a4eaf9a68e701e95 cited By 84 D. Stöffler N.A. Artemieva B.A. Ivanov L. Hecht T. Kenkmann R.T. Schmitt R.A. Tagle A. Wittmann article Moridis2004219 The Mallik site represents an onshore permafrost-associated gas hydrate accumulation in the Mackenzie Delta, Northwest Territories, Canada. A gas hydrate research well was drilled at the site in 1998. The objective of this study is the analysis of various gas production scenarios from five methane hydrate-bearing zones at the Mallik site. In Zone #1, numerical simulations using the EOSHYDR2 model indicated that gas production from hydrates at the Mallik site was possible by depressurizing a thin free gas zone at the base of the hydrate stability field. Horizontal wells appeared to have a slight advantage over vertical wells, while multiwell systems involving a combination of depressurization and thermal stimulation offered superior performance, especially when a hot noncondensible gas was injected. Zone #2, which involved a gas hydrate layer with an underlying aquifer, could yield significant amounts of gas originating entirely from gas hydrates, the volumes of which increased with the production rate. However, large amounts of water were also produced. Zones #3, #4 and #5 were lithologically isolated gas hydrate-bearing deposits with no underlying zones of mobile gas or water. In these zones, thermal stimulation by circulating hot water in the well was used to induce dissociation. Sensitivity studies indicated that the methane release from the hydrate accumulations increased with the gas hydrate saturation, the initial formation temperature, the temperature of the circulating water in the well, and the formation thermal conductivity. Methane production appears to be less sensitive to the specific heat of the rock and of the hydrate, and to the permeability of the formation. © 2004 Published by Elsevier B.V. 2004 English 09204105 10.1016/j.petrol.2004.02.015 Journal of Petroleum Science and Engineering 43 219-238 Earth Sciences Division, Lawrence Berkeley Natl. Laboratory, University of California, 1 Cyclotron Road, Berkeley, CA 94720, United States; United States Geological Survey, Denver, CO 80225-0046, United States; Geological Survey of Canada, Sidney, BC V8L 4B2, Canada; Japan National Oil Corporation, Chiba 261-0025, Japan; Adams Pearson Associates Inc., Calgary, Alta. T2P 3T6, Canada 3-4 Depressurization; Thermal stimulations, Computer simulation; Hydrates; Lithology; Methane; Specific heat; Thermal conductivity; Thermal effects, Gas fuel manufacture, gas hydrate; gas production; numerical model; permafrost, Canada; Mackenzie Delta; North America; Northwest Territories https://www.scopus.com/inward/record.uri?eid=2-s2.0-3442901975&doi=10.1016%2fj.petrol.2004.02.015&partnerID=40&md5=da3e821165d71b26f88b4f2448fbff05 cited By 204 G.J. Moridis T.S. Collett S.R. Dallimore T. Satoh S. Hancock B. Weatherill article Moridis2004175 The Mallik site represents an onshore permafrost-associated methane hydrate accumulation in the Mackenzie Delta, Northwest Territories, Canada. This study focuses on gas production at the Mallik site from hydrate deposits that are underlain by either a freewater zone (Class 2) or an impermeable boundary (Class 3). The production analysis was conducted with a numerical simulator that can model the nonisothermal CH4 release, phase behavior, and flow under conditions typical of CH4-hydrate deposits by solving the coupled equations of mass and heat balance. Accumulations with a CH4-hydrate saturation of at least 50% were studied. Dissociation was induced mainly by a combination of thermal stimulation and depressurization as hot fluids circulated between injection and production wells. The effects of salinity and of pressure changes at the wells were also accounted for. The production strategy resulted in a zero net water production. The simulation results indicated that the amount of CH4 released from the dissociating hydrate deposits is sensitive to the hydrate saturation, the initial temperature, the specific enthalpy, and the flow rate of the circulating fluids. © 2004 Society of Petroleum Engineers. 2004 English 10946470 10.2118/88039-PA SPE Reservoir Evaluation and Engineering 7 Society of Petroleum Engineers 175-183 Hydrology/Reservoir Dynamics Dept., Earth Sciences Division, Lawrence Berkeley Natl. Laboratory, Berkeley, CA, United States 3 Computer simulation; Enthalpy; Fluid dynamics; Hydrates; Methane; Pressurization; Saturation (materials composition); Thermal effects, Freewater zone; Gas production; Production wells; Water production, Gas fuel analysis, gas hydrate; hydrocarbon reserve; hydrocarbon technology; methane; numerical model; permafrost, Canada; Mackenzie Delta; North America; Northwest Territories https://www.scopus.com/inward/record.uri?eid=2-s2.0-3242769076&doi=10.2118%2f88039-PA&partnerID=40&md5=d7a20515ef2b0ef66b8c5d29ca4440d8 cited By 77 G.J. Moridis article Foulger200445 Most of 26 small (0.4≲ M ≲3.1) microearthquakes at Long Valley caldera in mid-1997, analyzed using data from a dense temporary network of 69 digital three-component seismometers, have significantly non-double-couple focal mechanisms, inconsistent with simple shear faulting. We determined their mechanisms by inverting P - and S -wave polarities and amplitude ratios using linear-programming methods, and tracing rays through a three-dimensional Earth model derived using tomography. More than 80% of the mechanisms have positive (volume increase) isotropic components and most have compensated linear-vector dipole components with outward-directed major dipoles. The simplest interpretation of these mechanisms is combined shear and extensional faulting with a volume-compensating process, such as rapid flow of water, steam, or CO2 into opening tensile cracks. Source orientations of earthquakes in the south moat suggest extensional faulting on ESE-striking subvertical planes, an orientation consistent with planes defined by earthquake hypocenters. The focal mechanisms show that clearly defined hypocentral planes in different locations result from different source processes. One such plane in the eastern south moat is consistent with extensional faulting, while one near Casa Diablo Hot Springs reflects en echelon right-lateral shear faulting. Source orientations at Mammoth Mountain vary systematically with location, indicating that the volcano influences the local stress field. Events in a 'spasmodic burst' at Mammoth Mountain have practically identical mechanisms that indicate nearly pure compensated tensile failure and high fluid mobility. Five earthquakes had mechanisms involving small volume decreases, but these may not be significant. No mechanisms have volumetric moment fractions larger than that of a force dipole, but the reason for this fact is unknown. Published by Elsevier B.V. 2004 English 03770273 10.1016/S0377-0273(03)00420-7 Journal of Volcanology and Geothermal Research 132 45-71 U.S. Geological Survey, 345 Middlefield Rd., Menlo Park, CA 94025, United States; Division of Earth and Ocean Sciences, Nicholas School of the Environment, Duke University, Durham, NC 27708-0235, United States 1 Crack initiation; Elastic moduli; Flow of water; Hydraulic fracturing; Stream flow; Stress analysis, Shear faulting; Tensile failure, Earthquakes, earthquake mechanism; faulting; focal mechanism; hydraulic fracture; microearthquake; moment tensor; seismicity; volcanic earthquake, California; Long Valley Caldera; North America; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-1642487285&doi=10.1016%2fS0377-0273%2803%2900420-7&partnerID=40&md5=13cb6623ddcf9e60690fd7d318c38526 cited By 120 G.R. Foulger B.R. Julian D.P. Hill A.M. Pitt E. Shalev article NoAuthor200453 2004 English 01492136 10.2118/0404-0053-jpt Journal of Petroleum Technology 56 Society of Petroleum Engineers (SPE) 53-54 4 https://www.scopus.com/inward/record.uri?eid=2-s2.0-1842831336&doi=10.2118%2f0404-0053-jpt&partnerID=40&md5=68d396766646b87484fb54745d41356f cited By 5 article Keller20041127 Yaxcopoil-1 (Yax-1), drilled within the Chicxulub crater, was expected to yield the final proof that this impact occurred precisely 65 Myr ago and caused the mass extinction at the Cretaceous-Tertiary (K/T) boundary. Instead, contrary evidence was discovered based on five independent proxies (sedimentologic, biostratigraphic, magnetostratigraphic, stable isotopic, and iridium) that revealed that the Chicxulub impact predates the K/T boundary by about 300,000 years and could not have caused the mass extinction. This is demonstrated by the presence of five bioturbated glauconite layers and planktic foraminiferal assemblages of the latest Maastrichtian zone CF1 and is corroborated by magnetostratigraphic chron 29r and characteristic late Maastrichtian stable isotope signals. These results were first presented in Keller et al. (2004). In this study, we present more detailed evidence of the presence of late Maastrichtian planktic foraminifera, sedimentologic, and mineralogic analyses that demonstrate that the Chicxulub impact breccia predates the K/T boundary and that the sediments between the breccia and the K/T boundary were deposited in a normal marine environment during the last 300,000 years of the Cretaceous. © Meteoritical Society, 2004. Printed in USA. 2004 10.1111/j.1945-5100.2004.tb01133.x Meteoritics and Planetary Science 39 1127-1144 Department of Geosciences, Princeton University, Princeton, NJ 08544, United States; Geological Institute, University of Neuchâtel, Neuchâtel CH-2007, Switzerland; Geologisches Institut, Universität Karlsruhe, Karlsruhe 76128, Germany; Institut für Mineral/Geochemie, Universität Karlsruhe, Karlsruhe 76128, Germany 7 https://www.scopus.com/inward/record.uri?eid=2-s2.0-3943071839&doi=10.1111%2fj.1945-5100.2004.tb01133.x&partnerID=40&md5=22c0dc3c1482b077ff53cf95b600ae63 cited By 47 G. Keller T. Adatte W. Stinnesbeck D. Stüben Z. Berner U. Kramar M. Harting article Tuchscherer2004955 Approximately 100 m of impactites were retrieved from the ICDP borehole Yaxcopoil-1 (Yax-1), located ∼60 km south-southwest from the center of the Chicxulub impact crater on the Yucatán Peninsula of Mexico. Here, we characterize and discuss this impact breccia interval according to its geochemical characteristics. Chemical analysis of samples from all five recognized breccia units reveals that the impactites are of heterogeneous composition with regard to both major and trace elements at the single sample (8-16 cm3) scale. This is primarily due to a strong mixing relationship between carbonate and silicate fractions. However, averaged compositions for suevitic units 1 to 3 are similar, and the silicate fraction (after removal of the carbonate component) indicates thorough mixing and homogenization. Analysis of the green melt breccia horizon, unit 4, indicates that it contains a distinct mafic component. Large brown melt particles (in units 2, 3, and 4) represent a mixture of feldspathic and mafic components, with high CaO abundances. Unit 5 shows the greatest compositional diversity, with highly variable abundances of SiO2, CaO, and MgO. Inter-sample heterogeneity is the result of small sample size combined with inherent heterogeneous lithological compositions, highly variable particle size of melt and lithic components, and post-depositional alteration. In contrast to samples from the Y6 borehole from closer to the center of the structure, Yax-1 impactites have a strong carbonate component. Elevated loss on ignition, Rb, and Cs contents in the upper two impactite units indicate strong interaction with seawater. The contents of the siderophile elements, including Ni, Co, Ir, and Cr, do not indicate the presence of a significant extraterrestrial component in the Yax-1 impactites. © Meteoritical Society, 2004. 2004 10.1111/j.1945-5100.2004.tb00939.x Meteoritics and Planetary Science 39 955-978 Impact Cratering Research Group, School of Geosciences, University of the Witwatersrand, Private Bag 3, Johannesburg 2050, South Africa; Department of Geological Sciences, University of Vienna, Althanstrasse 14, Vienna A-1090, Austria 6 https://www.scopus.com/inward/record.uri?eid=2-s2.0-3943069009&doi=10.1111%2fj.1945-5100.2004.tb00939.x&partnerID=40&md5=d66521d4bfb9f98ead183089abd39d92 cited By 20 M.G. Tuchscherer M.U. Reimold C. Koeberl R.L. Gibson article Rebolledo-Vieyra2004821 We report the magnetostratigraphy of the sedimentary sequence between the impact breccias and the post-impact carbonate sequence conducted on samples recovered by Yaxcopoil-1 (Yax-1). Samples of impact breccias show reverse polarities that span up to ∼56 cm into the post-impact carbonate lithologies. We correlate these breccias to those of PEMEX boreholes Yucatán-6 and Chicxulub-1, from which we tied our magnetostratigraphy to the radiometric age from a melt sample from the Yucatán-6 borehole. Thin section analyses of the carbonate samples showed a significant amount of dark minerals and glass shards that we identified as the magnetic carriers; therefore, we propose that the mechanism of magnetic acquisition within the carbonate rocks for the interval studied is detrital remanent magnetism (DRM). With these samples, we constructed the scale of geomagnetic polarities where we find two polarities within the sequence, a reverse polarity event within the impact breccias and the base of the post-impact carbonate sequence (up to 794.07 m), and a normal polarity event in the last ∼20 cm of the interval studied. The polarities recorded in the sequence analyzed are interpreted to span from chron 29r to 29n, and we propose that the reverse polarity event lies within the 29r chron. The magnetostratigraphy of the sequence studied shows that the horizon at 794.11 m deep, interpreted as the K/T boundary, lies within the geomagnetic chron 29r, which contains the K/T boundary. © Meteoritical Society, 2004. 2004 10.1111/j.1945-5100.2004.tb00932.x Meteoritics and Planetary Science 39 821-829 Lab. Scis. du Climat/l'Environnement, Unite de Recherche Mixte CNRS-CEA, Gif-sur-Yvette, France; Laboratorio de Paleomagnetismo, Instituto de Geofisica, UNAM, Coyoacán, Mexico City, Mexico 6 https://www.scopus.com/inward/record.uri?eid=2-s2.0-3943080587&doi=10.1111%2fj.1945-5100.2004.tb00932.x&partnerID=40&md5=d9e2a908451b590360715ded1e161272 cited By 30 M. Rebolledo-Vieyra J. Urrutia-Fucugauchi article Erzinger2004 The real-time mud gas monitoring during drilling of the 2.2 km deep SAFOD Pilot Hole has proved successful. A nearly complete depth profile was obtained for methane, radon, helium, and, with limitations, for carbon dioxide. Within the sedimentary section (0-768 m) mud gas yielded the highest CH4, CO2, and 222Rn concentrations, whereas He was comparably low. Four major gas-rich zones were identified. Methane is a mixture of microbial and thermogenic origin. Mud gas concentrations of CH4 and Rn are much lower in the underlying granitic rocks and the average background level of He is higher. In addition to several gas-rich zones, two shear zones inferred from geophysical measurements are also indicated by increased mud gas concentrations. Gas results permit speculation that one major shear zone is hydraulically connected to the sedimentary section above. Up to 9% of the helium is of mantle origin, which is probably a lower limit. Copyright 2004 by the American Geophysical Union. 2004 English 00948276 10.1029/2003GL019395 Geophysical Research Letters 31 L15S18 1-4 GeoForschungsZentrum Potsdam, Potsdam D-14473, Germany 15 Carbon dioxide; Drilling; Geophysical prospecting; Granite; Helium; Methane; Mud logging; Radon; Sedimentology, Geophysical measurements; Mantle; Mud gas concentrations; Pilot holes, Boreholes, borehole geophysics; borehole logging; gas; San Andreas Fault; source rock, California; North America; Parkfield; United States; Western Hemisphere; World https://www.scopus.com/inward/record.uri?eid=2-s2.0-7044235222&doi=10.1029%2f2003GL019395&partnerID=40&md5=99626d15fa4304c7a63b6072fd1cb9cc cited By 25 J. Erzinger T. Wiersberg E. Dahms article Fulton2004 Improved interpretations of the strength of the San Andreas Fault near Parkfield, CA based on thermal data require quantification of processes causing significant scatter and uncertainty in existing heat flow data. These effects include topographic refraction, heat advection by topographically-driven groundwater flow, and uncertainty in thermal conductivity. Here, we re-evaluate the heat flow data in this area by correcting for full 3-D terrain effects. We then investigate the potential role of groundwater flow in redistributing fault-generated heat, using numerical models of coupled heat and fluid flow for a wide range of hydrologic scenarios. We find that a large degree of the scatter in the data can be accounted for by 3-D terrain effects, and that for plausible groundwater flow scenarios frictional heat generated along a strong fault is unlikely to be redistributed by topographically-driven groundwater flow in a manner consistent with the 3-D corrected data. Copyright 2004 by the American Geophysical Union. 2004 English 00948276 10.1029/2003GL019378 Geophysical Research Letters 31 L15S15 1-4 Department of Geology and Geophysics, University of Wyoming, Laramie, WY 82071, United States; Department of Geology and Geophysics, University of Utah, Salt Lake City, UT 84112, United States; U.S. Geological Survey, Menlo Park, CA, United States 15 Chemical analysis; Data acquisition; Groundwater; Hydrology; Refraction; Topology, Parkfield; Thermal data, Heat transfer, borehole geophysics; heat flow; San Andreas Fault; strength; weak rock, California; North America; Parkfield; United States; Western Hemisphere; World https://www.scopus.com/inward/record.uri?eid=2-s2.0-7244234028&doi=10.1029%2f2003GL019378&partnerID=40&md5=03d14cf20aafb193e0bdce7c57efa3df cited By 31 P.M. Fulton D.M. Saffer R.N. Harris B.A. Bekins article Urrutia-Fucugauchi2004787 2004 10.1111/j.1945-5100.2004.tb00928.x Meteoritics and Planetary Science 39 787-790 Instituto de Geofisica, Univ. Nacl. Autonoma de Mexico, Mexico City, Coyoacán 04510, Mexico; Earth Sciences and Engineering, Imperial College London, London SW7 2AZ, United Kingdom; Natural History Museum, Humboldt University, Berlin D-10099, Germany; Department of Geology, Vrije Universiteit Brusse, Pleinaan 2, Brussels B-1050, Belgium 6 https://www.scopus.com/inward/record.uri?eid=2-s2.0-3943079941&doi=10.1111%2fj.1945-5100.2004.tb00928.x&partnerID=40&md5=4cbc53cc65325240641ba4cf421427d4 cited By 72 J. Urrutia-Fucugauchi J. Morgan D. Stöffler P. Claeys article Townend2004 Throughout central and southern California, a uniform NNE-SSW direction of maximum horizontal compressive stress is observed that is remarkably consistent with the superposition of stresses arising from lateral variations in lithospheric buoyancy in the western United States, and farfield Pacific-North America plate interaction. In central California, the axis of maximum horizontal compressive stress lies at a high angle to the San Andreas fault (SAF). Despite relatively few observations near (±10 km) the fault, observations in the greater San Francisco Bay area indicate an angle of as much as 85°, implying extremely low fault strength. In southern California, observations of stress orientations near the SAF are rotated slightly counter-clockwise with respect to the regional field. Nevertheless, we observe an approximately constant angle between the SAF and the maximum horizontal stress direction of 68 ± 7° along ∼400 km of the fault, indicating that the SAF has moderately low frictional strength in southern California. Copyright 2004 by the American Geophysical Union. 2004 English 00948276 10.1029/2003GL018918 Geophysical Research Letters 31 L15S11 1-5 School of Earth Sciences, Victoria University of Wellington, P.O. Box 600, Wellington, New Zealand; Department of Geophysics, Stanford University, Stanford, CA 94305-2215, United States 15 Buoyancy; Compressive stress; Geophysics; Lithography; Stress analysis, Lithospheric buoyancy; Stress orientations; Tectonic stress, Tectonics, in situ stress; San Andreas Fault; stress field; tectonic setting https://www.scopus.com/inward/record.uri?eid=2-s2.0-7044280211&doi=10.1029%2f2003GL018918&partnerID=40&md5=ae3a7689f308a81f0a7799066a2840fd cited By 211 M.D. Zoback article Chand2004 Observations of velocities in sediments containing gas hydrates show that the strength of sediments increases with hydrate saturation. Hence it is expected that the attenuation of these sediments will decrease with increasing hydrate saturation. However, sonic log measurements in the Mallik 2L-38 well and cross hole tomography measurements in the Mallik field have shown that attenuation increases with hydrate saturation. We studied a range of mechanisms by which increasing hydrate saturation could cause increased attenuation. We found that a difference in permeability between the host sediment and the newly formed hydrate can produce the observed effect. We modelled attenuation in terms of Biot and squirt flow mechanisms in composite media. We have used our model to predict observed attenuations in the Mallik 2L-38 well, Mackenzie Delta, Canada. Copyright 2004 by the American Geophysical Union. 2004 English 00948276 10.1029/2004GL020292 Geophysical Research Letters 31 L14609 1-4 School of Ocean and Earth Science, Southampton Oceanography Centre, European Way, Southampton SO14 3ZH, United Kingdom 14 Attenuation; Gas hydrates; Mechanical permeability; Sediments, Seismic attenuation; Squirt flow mechanism, Seismic waves, borehole geophysics; gas hydrate; permeability; seismic attenuation; seismic wave, Canada; Mackenzie Delta; North America; Northwest Territories https://www.scopus.com/inward/record.uri?eid=2-s2.0-4644323579&doi=10.1029%2f2004GL020292&partnerID=40&md5=7700212f10782935fe7fa15a8290dc90 cited By 51 S. Chand T.A. Minshull article Nakada200414 Article 2004 English 00168556 Geotimes 49 14 – 15 3 https://www.scopus.com/inward/record.uri?eid=2-s2.0-34447269564&partnerID=40&md5=85473aab8f6a1656514531e93f878510 Cited by: 5 Setsuya Nakada John Eichelberger article Stinnesbeck20041042 CSDP core Yaxcopoil-1 was drilled to a depth of 1,511 m within the Chicxulub crater. An organic-rich marly limestone near the base of the hole (1,495 to 1,452 m) was deposited in an open marine shelf environment during the latest Cenomanian (uppermost Rotalipora cushmani zone). The overlying sequence of limestones, dolomites and anhydrites (1,495 to 894 m) indicates deposition in various carbonate platform environments (e.g., sabkhas, lagoons). A 100-m-thick suevite breccia (894-794 m) identifies the Chicxulub impact event. Above the suevite breccia is a dolomitic limestone with planktic foraminiferal assemblages indicative of Plummerita hantkeninoides zone CF1, which spans the last 300 ky of the Maastrichtian. An erosional surface 50 cm above the breccia/dolomite contact marks the K/T boundary and a hiatus. Limestones above this contact contain the first Tertiary planktic foraminifera indicative of an upper P. eugubina zone P1a(2) age. Another hiatus 7 cm upsection separates zone P1a(2) and hemipelagic limestones of planktic foraminiferal Zone P1c. Planktic foraminiferal assemblages of Zone Plc to P3b age are present from a depth of 794.04 up to 775 m. The Cretaceous carbonate sequence appears to be autochthonous, with a stratigraphic sequence comparable to late Cretaceous sediments known from outside the Chicxulub crater in northern and southern Yucatan, including the late Cenomanian organic-rich marly limestone. There is no evidence that these sediments represent crater infill due to megablocks sliding into the crater, such as major disruption of sediments, chaotic changes in lithology, overturned or deep dipping megablocks, major mechanical fragmentation, shock or thermal alteration, or ductile deformation. Breccia units that are intercalated in the carbonate platform sequence are intraformational in origin (e.g., dissolution of evaporites) and dykes are rare. Major disturbances of strata by the impact therefore appear to have been confined to within less than 60 km from the proposed impact center. Yaxcopoil-1 may be located outside the collapsed transient crater cavity, either on the upper end of an elevated and tilted horst of the terrace zone, or even outside the annular crater cavity. The Chicxulub site thus records a large impact that predates the K/T boundary impact and mass extinction. © Springer-Verlag 2004. 2004 10.1007/s00531-004-0431-6 International Journal of Earth Sciences 93 1042-1065 Geologisches Institut, Universität Karlsruhe, 76128 Karlsruhe, Germany; Department of Geosciences, Princeton University, Princeton, NJ 08544, United States; Geological Institute, University of Neuchâtel, 2007 Neuchâtel, Switzerland; Institut fur Mineralogie/Geochemie, Universität Karlsruhe, 76128 Karlsruhe, Germany 6 https://www.scopus.com/inward/record.uri?eid=2-s2.0-10044288403&doi=10.1007%2fs00531-004-0431-6&partnerID=40&md5=2b968bbd503abe2f17ec5cc32b49b720 cited By 30 W. Stinnesbeck G. Keller T. Adatte M. Harting D. Stüben G. Istrate U. Kramar article Seaman2004 H2O, CO2, S, Cl, and F concentrations are reported for 556 glasses from the submarine section of the 1999 phase of HSDP drilling in Hilo, Hawaii, providing a high-resolution record of magmatic volatiles over ∼200 kyr of a Hawaiian volcano's lifetime. Glasses range from undegassed to having lost significant volatiles at near-atmospheric pressure. Nearly all hyaloclastite glasses are degassed, compatible with formation from subaerial lavas that fragmented on entering the ocean and were transported by gravity flows down the volcano flank. Most pillows are undegassed, indicating submarine eruption. The shallowest pillows and most massive lavas are degassed, suggesting formation by subaerial flows that penetrated the shoreline and flowed some distance under water. Some pillow rim glasses have H2O and S contents indicating degassing but elevated CO2 contents that correlate with depth in the core; these tend to be more fractionated and could have formed by mixing of degassed, fractionated magmas with undegassed magmas during magma chamber overturn or by resorption of rising CO2-rich bubbles by degassed magmas. Intrusive glasses are undegassed and have CO2 contents similar to adjacent pillows, indicating intrusion shallow in the volcanic edifice. Cl correlates weakly with H2O and S, suggesting loss during low-pressure degassing, although most samples appear contaminated by seawater-derived components. F behaves as an involatile incompatible element. Fractionation trends were modeled using MELTS. Degassed glasses require fractionation at PH2o ≈ 5-10 bars. Undegassed low-SiO2 glasses require fractionation at PH2O ≈ 50 bars. Undegassed and partially degassed high-SiO2 glasses can be modeled by coupled crystallization and degassing. Eruption depths of undegassed pillows can be calculated from their volatile contents assuming vapor saturation. The amount of subsidence can be determined from the difference between this depth and the sample's depth in the core. Assuming subsidence at 2.5 mm/y, the amount of subsidence suggests ages of ∼500 ka for samples from the lower 750 m of the core, consistent with radiometric ages. H2O contents of undegassed low-SiO2 HSDP2 glasses are systematically higher than those of high-SiO2 glasses, and their H2O/K2O and H 2O/Ce ratios are higher than typical tholeiitic pillow rim glasses from Hawaiian volcanoes. Copyright 2004 by the American Geophysical Union. Article 2004 English 15252027 10.1029/2003GC000596 Geochemistry, Geophysics, Geosystems 5 9 https://www.scopus.com/inward/record.uri?eid=2-s2.0-33644618820&doi=10.1029%2f2003GC000596&partnerID=40&md5=81a8f586ecf7b71b9339f042e0e3782f Cited by: 46; All Open Access, Green Open Access Caroline Seaman Sarah Bean Sherman Michael O. Garcia Michael B. Baker Brian Balta Edward Stolper article Horiuchi2004408 The dynamics of cosmogenic 10Be contents in the BDP-96-1 (100 to 200 m) and BDP-98-2 (200 to 600 m) cores was used to test published magnetostratigraphic scales for the Miocene section and to time the core base. Only one of three alternative scales for the BDP-98 core tested against the 10Be decay of T1/2 = 1.5 myr showed a perfect consistency with the decay law. The basal age of the 600 m BDP-98 section was estimted at 8.4 myr. Article 2004 Russian 00167886 Geologiya i Geofizika 45 408 – 412 3 Eurasia; Lake Baikal; Russian Federation; cosmogenic radionuclide; magnetostratigraphy; Miocene https://www.scopus.com/inward/record.uri?eid=2-s2.0-2942565826&partnerID=40&md5=c2db935e1c756707be81df1a660cf61a Cited by: 3 K. Horiuchi E.L. Gol'dberg H. Matsuzaki K. Kobayashi Y. Shibata article LIU2004411 Orthogneisses are the major country rocks hosting eclogites in the Sulu UHP terrane, eastern China. All of the analyzed orthogneiss cores from the main drilling hole of the Chinese Continental Scientific Drilling Project (CCSD-MH) have similar major and trace element compositions and a granite protolith. These rocks have relatively high LREE/HREE ratios, strong negative Eu anomalies (Eu/Eu*=0.20–0.39), and negative Ba anomalies (Ba/Ba*=0.25–0.64). Coesite and coesite-bearing UHP mineral assemblages are common inclusions in zircons separated from orthogneiss, paragneiss, amphibolite, and (retrograded) eclogite of the CCSD-MH. This suggests that the eclogite, together with its country rocks, experienced in situ ultrahigh-pressure (UHP) metamorphism. Laser Raman spectroscopy and cathodoluminescence (CL) images show that zircons from the orthogneisses are zoned and that they have distinct mineral inclusions in the different zones. Most zircons retain early magmatic cores with abundant low-pressure mineral inclusions, which are mantled with metamorphic zircon-containing inclusions of coesite and other UHP minerals. The outermost rims on these grains contain low-pressure mineral inclusions, such as quartz and albite. SHRIMP U–Pb dating of the zoned zircons gives three discrete and meaningful groups of ages: Proterozoic ages for the protolith, 227±2 Ma for the coesite-bearing mantles, and 209±3 Ma for the amphibolite facies retrograde rims. The widespread occurrence of UHP mineral inclusions in zircons from the Sulu metamorphic belt dated at about 227 Ma suggests that voluminous continental crust experienced late Triassic subduction to depths of at least 120 km and perhaps more than 200 km. Eighteen million years later, the terrane was rapidly exhumed to midcrustal levels, and the UHP rocks were overprinted by amphibolite facies metamorphism. The exhumation rate deduced from the zircon age data and previously obtained metamorphic P–T data is estimated to be 5.6–11.0 km/Ma. Such rapid exhumation of the Sulu UHP terrane may be due to the buoyancy forces produced by subduction of low-density continental material into the deep mantle. 2004 0024-4937 https://doi.org/10.1016/j.lithos.2004.08.001 Lithos 78 411-429 4 Orthogneiss, Mineral inclusion in zircon, UHP metamorphism, SHRIMP U–Pb dating, Chinese Continental Scientific Drilling Project https://www.sciencedirect.com/science/article/pii/S0024493704002452 Fulai Liu Zhiqin Xu Huaimin Xue article Ribe2004793 The sea floor around the Hawaiian island chain is unusually shallow. New seismic evidence suggests that this up-raised 'swell' is partly due to heating and thinning of the lithosphere beneath. 2004 English 00280836 10.1038/427793a Nature 427 793-795 Inst. de Physique du Globe de Paris, 4 Place Jussieu, Paris 75252 Cedex 05, France 6977 Earth atmosphere; Sea level; Seismology, Lithosphere, Oceanography, crustal thickness; seafloor, asthenospheric upwelling; earthquake; geology; gravity; heat transfer; priority journal; short survey; United States, Hawaiian Islands; Pacific islands; Pacific Ocean, Hawaiia https://www.scopus.com/inward/record.uri?eid=2-s2.0-1542378980&doi=10.1038%2f427793a&partnerID=40&md5=fb91a782d85a30d53d9b6d9e60c2612d cited By 11 N.M. Ribe article Chavarria2004 In July 2002 we installed a vertical array of seismometers in the San Andreas Fault Observatory at Depth (SAFOD) Pilot Hole (PH). The bottom of this 32 level, 1240 m long array of 3- components is located at a depth of ∼2100 m below ground. Surface-explosion and microearthquake seismograms recorded by the array give valuable insights into the structure of the SAFOD site. The ratios of P- and S-wave velocities.(Vp/Vs) along the array suggest the presence of two faults intersecting the PH. The Vp/Vs ratios also depend on source-location, with high values to the NW, and lower ones to the SE, correlating with high and low creep rates along the SAF, respectively. Since higher ratios can be produced by increasing fluid saturation, we suggest that this effect might account for both our observations and their correlation with the creep distribution. Copyright 2004 by the American Geophysical Union. 2004 English 00948276 10.1029/2003GL019382 Geophysical Research Letters 31 L12S07 1-5 Division of Earth and Ocean Sciences, Duke University, Durham, NC 27708, United States 12 Correlation methods; Creep; Earthquakes; Geophysics; Observatories; Site selection; Wave propagation; Creep; Shear waves; Strike-slip faults; Wave propagation, Fluid saturation; Pilot hole (PH); Seismic arrays; Seismograms, Seismology; Seismology, earthquake; San Andreas Fault; seismic wave; seismometry; wave propagation, Creep distribution; Fluid saturations; P- and S-wave velocities; Propagation effect; San Andreas fault; Source location; Surface explosions; Vertical arrays https://www.scopus.com/inward/record.uri?eid=2-s2.0-6044266087&doi=10.1029%2f2003GL019382&partnerID=40&md5=8821e24c660fa234ccfd6ddc30b1a920 cited By 11 J.A. Chavarria E. Shalev article Nelson2004 2004 Meteoritics and Planetary Science 39 A76 University of New Mexico, Institute of Meteoritics, Albuquerque, NM 87131, United States; Department of Earth/Planetary Sci., Albuquerque, NM 87131, United States SUPPL. https://www.scopus.com/inward/record.uri?eid=2-s2.0-4043083631&partnerID=40&md5=44a7d040414cb1cf4d226603425cbc50 cited By 1 M.J. Nelson H.E. Newsom C.K. Shearer F.J.M. Rietmeijer article Chapman20041 Near-Earth asteroids (NEAs) have struck the Earth throughout its existence. During epochs when life was gaining a foothold ∼ 4 Ga, the impact rate was thousands of times what it is today. Even during the Phanerozoic, the numbers of NEAs guarantee that there were other impacts, possibly larger than the Chicxulub event, which was responsible for the Cretaceous-Tertiary extinctions. Astronomers have found over 2500 NEAs of all sizes, including well over half of the estimated 1100 NEAs >1 km diameter. NEAs are mostly collisional fragments from the inner half of the asteroid belt and range in composition from porous, carbonaceous- chondrite-like to metallic. Nearly one-fifth of them have satellites or are double bodies. When the international telescopic Spaceguard Survey, which has a goal of discovering 90% of NEAs >1 km diameter, is completed, perhaps as early as 2008, nearly half of the remaining impact hazard will be from land or ocean impacts by bodies 70-600 m diameter. (Comets are expected to contribute only about 1% of the total risk.) The consequences of impacts for civilization are potentially enormous, but impacts are so rare that worldwide mortality from impacts will have dropped to only about 150 per year (averaged over very long durations) after the Spaceguard goal has, presumably, ruled out near- term impacts by 90% of the most dangerous ones; that is, in the mid- range between very serious causes of death (disease, auto accidents) and minor but frightening ones (like shark attacks). Differences in perception concerning this rather newly recognized hazard dominate evaluation of its significance. The most likely type of impact events we face are hyped or misinterpreted predicted impacts or near-misses involving small NEAs. © 2004 Elsevier B.V. All rights reserved. 2004 10.1016/j.epsl.2004.03.004 Earth and Planetary Science Letters 222 1-15 Southwest Research Institute, 1050 Walnut St., Boulder, CO 80302, United States 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-2342457176&doi=10.1016%2fj.epsl.2004.03.004&partnerID=40&md5=2e91c958c587ffbae4a9ff04a0fc52e4 cited By 105 C.R. Chapman article Cornet2004235 Editorial 2004 English 16310713 10.1016/j.crte.2004.02.001 Comptes Rendus - Geoscience 336 Elsevier Masson SAS 235 – 241 4-5 Gulf of Corinth; Ionian Sea; Mediterranean Sea; rift zone; seismotectonics https://www.scopus.com/inward/record.uri?eid=2-s2.0-1942537641&doi=10.1016%2fj.crte.2004.02.001&partnerID=40&md5=d514674844f86e45db90ef939e4b3c8f Cited by: 27 Francois H. Cornet Pascal Bernard Isabelle Moretti article Li2004827 The volcanism responsible for creating the chain of the Hawaiian islands and seamounts is believed to mark the passage of the oceanic lithosphere over a mantle plume. In this picture hot material rises from great depth within a fixed narrow conduit to the surface, penetrating the moving lithosphere. Although a number of models describe possible plume-lithosphere interactions, seismic imaging techniques have not had sufficient resolution to distinguish between them. Here we apply the S-wave 'receiver function' technique to data of three permanent seismic broadband stations on the Hawaiian islands, to map the thickness of the underlying lithosphere. We find that under Big Island the lithosphere is 100-110 km thick, as expected for an oceanic plate 90-100 million years old that is not modified by a plume. But the lithosphere thins gradually along the island chain to about 50-60 km below Kauai. The width of the thinning is about 300 km. In this zone, well within the larger-scale topographic swell, we infer that the rejuvenation model (where the plume thins the lithosphere) is operative; however, the larger-scale topographic swell is probably supported dynamically. 2004 English 00280836 10.1038/nature02349 Nature 427 827-829 GeoForschungsZentrum Potsdam, Telegrafenberg, 14473 Potsdam, Germany; Freie Universität Berlin, FR Geophysik, Malteserstrasse 74-100, 12249 Berlin, Germany 6977 Earth atmosphere; Imaging systems; Seismology; Surface topography, Lithosphere, Oceanography, crustal thickness; lithosphere; mantle plume; seismic tomography; volcanism, article; atmosphere; heating; imaging system; island (geological); lithosphere; mechanics; plume; priority journal; sea; signal detection; temperature measurement; thickness; topography; United States; volcano, Hawaiian Islands; Pacific islands; Pacific Ocean, Hawaiia https://www.scopus.com/inward/record.uri?eid=2-s2.0-1542319094&doi=10.1038%2fnature02349&partnerID=40&md5=cdb739f9cedb4f8918a4d08ada1ce0dd cited By 219 X. Li R. Kind X. Yuan I. Wölbern W. Hanka article Rettenmaier2004415 In the frame of the EU Project Corinth Rift Laboratory (CRL), the AIG10 borehole was successfully drilled from July until September 2002 through the Aigion normal fault in the harbour of Aigion, northern Peloponnesus, Greece. The scientific objective focuses on the investigation of fault mechanics and the relationship with fluid flow and geochemistry, fluid pressure, stress- and strain fields and earthquakes. Recognition of stratification encountered in the AIG10 borehole is based on an online analysis of well cuttings (0-708.8 m and 787.4-1001 m), core descriptions (708.8-787.4 m), monitoring of drilling parameters, as well as a preliminary geophysical well-log interpretation (0-1001 m). Geologically, the area is part of the Olonos-Pindos tectonic nappe, which is overthrusted on the Tripolitza unit during the Alpine orogeny. The litho-log of the AIG10 borehole comprises at first syn-rift deposits (graben fill). At 496 m, the Olonos-Pindos tectonic unit was encountered, however, not as expected in the platy limestones, but in the Olonos-Pindos radiolarite. The borehole has crossed at least one thrust-fault zone and a major normal fault zone at 760 m. This normal fault zone separates well-fractured platy, micritic limestone in the hangingwall from highly fractured radiolarite in the footwall, both of the Olonos-Pindos tectonic unit. The observed succession of multiple imbrication is an indicator of Alpine tectonic activity, whereas normal faulting is of the Miocene-Quaternary extension of the Gulf of Corinth, confirming our expectations gained from geologic-tectonic fieldwork. © 2004 Académie des sciences. Published by Elsevier SAS. All rights reserved. Article 2004 French 16310713 10.1016/j.crte.2003.12.011 Comptes Rendus - Geoscience 336 415 – 423 4-5 Gulf of Corinth; Ionian Sea; Mediterranean Sea; borehole geophysics; drilling; normal fault; rift zone; seismotectonics; stratigraphic correlation https://www.scopus.com/inward/record.uri?eid=2-s2.0-1942505728&doi=10.1016%2fj.crte.2003.12.011&partnerID=40&md5=d0908c684af0e37a8c7cc28ec5c84770 Cited by: 14 Detlev Rettenmaier Vlad Giurgea Heinz Hötzl Andrea Förster article Bauluz2004209 Study by transmission electron microscopy of samples from the Cretaceous-Tertiary (K-T) boundary clay at Flaxbourne River and Woodside Creek, New Zealand, has revealed the occurrence of nanometer-sized meteorite impact-derived glass. The average glass composition is exceptionally Ca-rich and is distinct from other glass found on Earth, apart from glass inferred to be of impact origin at Mexican and Haitian K-T sites. The glass shards are partially altered to montmorillonite-like smectite, with the dominant interlayer cation, Ca, reflecting the composition of the parent glass. The data imply a heterogeneous global distribution in composition of K-T boundary impact glass: Si-rich and Ca-rich in Mexico and Haiti, Si-rich in Denmark, and Ca-rich in New Zealand. This heterogeneous distribution may relate to dispersal processes similar to those used to account for the asymmetric distribution of clastic debris from the Chicxulub impact site. However, recent discovery of an impact crater of K-T boundary age in Ukraine raises the possibility of impact clusters which produce material of heterogeneous composition. © 2004 Elsevier B.V. All rights reserved. 2004 10.1016/S0012-821X(04)00011-1 Earth and Planetary Science Letters 219 209-219 Cristalografia y Mineralogía, Depto. de Ciencias de la Tierra, Universidad de Zaragoza, Zaragoza 50009, Spain; Department of Geological Sciences, The University of Michigan, Ann Arbor, MI 48109-1063, United States; Inst. of Geol./Nuclear Sciences, P.O. Box 30-368, Lower Hutt, New Zealand 3-4 https://www.scopus.com/inward/record.uri?eid=2-s2.0-1542644777&doi=10.1016%2fS0012-821X%2804%2900011-1&partnerID=40&md5=11361bcea550fd35556d1fe2c9af9d0b cited By 17 B. Bauluz D.R. Peacor article Kenkmann20041069 As part of the ICDP Chicxulub Scientific Drilling Project, the Yaxcopoil-1 (Yax-1) bore hole was drilled 60 km south-southwest of the center of the 180 km-diameter Chicxulub impact structure down to depth of 1511 m. A sequence of 615 m of deformed Cretaceous carbonates and sulfates was recovered below a 100 m-thick unit of suevitic breccias and 795 m of post-impact Tertiary rocks. The Cretaceous rocks are investigated with respect to deformation features and shock metamorphism to better constrain the deformational overprint and the kinematics of the cratering process. The sequence displays variable degrees of impact-induced brittle damage and post-impact brittle deformation. The degree of tilting and faulting of the Cretaceous sequence was analyzed using 360°-core scans and dip-meter log data. In accordance with lithological information, these data suggest that the sedimentary sequence represents a number of structural units that are tilted and moved with respect to each other. Three main units and nine sub-units were discriminated. Brittle deformation is most intense at the top of the sequence and at 1300-1400 m. Within these zones, suevitic dikes, polymict clastic dikes, and impact melt rock dikes occur and may locally act as decoupling horizons. The degree of brittle deformation depends on lithology; massive dolomites are affected by penetrative faulting, while stratified calcarenites and bituminous limestones display localized faulting. The deformation pattern is consistent with a collapse scenario of the Chicxulub transient crater cavity. It is believed that the Cretaceous sequence was originally located outside the transient crater cavity and eventually moved downward and toward the center to its present position between the peak ring and the crater rim, thereby separating into blocks. Whether or not the stack of deformed Cretaceous blocks was already displaced during the excavation process remains an open question. The analysis of the deformation microstructure indicates that a shock metamorphic overprint is restricted to dike injections with an exception of the so called "paraconglomerate." Abundant organic matter in the Yax-1 core was present before the impact and was mobilized by impact-induced heating and suggests that &gt;12 km3 of organic material was excavated during the cratering process. Meteoritical Society, 2004. 2004 10.1111/j.1945-5100.2004.tb01129.x Meteoritics and Planetary Science 39 1069-1088 Institut für Mineralogie, Museum für Naturkunde, Humboldt Universität Berlin, Invalidenstrasse 43, Berlin 10115, Germany 7 https://www.scopus.com/inward/record.uri?eid=2-s2.0-3943060965&doi=10.1111%2fj.1945-5100.2004.tb01129.x&partnerID=40&md5=86492abe071146954b7763a9b059b28e cited By 30 T. Kenkmann A. Wittmann D. Scherler conference Boness2004 A comprehensive suite of geophysical logs was collected in the SAFOD Pilot Hole in Parkfield, CA. from a depth of 775 m to 2150 m in highly fractured Salinian granite. The Pilot Hole intersected numerous macroscopic fractures and faults with extremely varied orientations. Despite the highly variable orientation of the fractures and faults, the fast polarization direction of the shear waves is very consistent with the direction of maximum horizontal compression determined from wellbore breakouts and drilling induced tensile fractures. At least three major shear zones were intersected by the borehole that are characterized by anomalously low velocity and resistivity, anomalously high shear velocity anisotropy and an absence of stress-induced wellbore breakouts (which suggests anomalously low differential stress). We argue that the physical mechanism responsible for the seismic velocity anisotropy observed in the Pilot Hole is the preferential closure of fractures in response to an anisotropic stress state. Copyright 2004, ARMA, American Rock Mechanics Association. 2004 English Gulf Rocks 2004 - 6th North America Rock Mechanics Symposium, NARMS 2004 American Rock Mechanics Association (ARMA) Department of Geophysics, Stanford University, California, United States Anisotropy; Boreholes; Fracture; Oil field equipment; Rock mechanics; Rocks; Seismic waves; Seismology; Shear waves; Velocity, Anisotropic stress; Differential stress; Drilling-induced tensile fractures; Fractures and faults; Macroscopic fractures; Physical mechanism; Polarization direction; Variable orientation, Shear flow https://www.scopus.com/inward/record.uri?eid=2-s2.0-85019707095&partnerID=40&md5=6e9378408816e3f32e3f52393d287955 cited By 9 N.L. Boness M.D. Zoback article Boness2004 A comprehensive suite of geophysical logs was collected in the SAFOD Pilot Hole from a depth of 775 m to 2150 m in highly fractured Salinian granite. The Pilot Hole intersected numerous macroscopic fractures and faults with extremely varied orientations. Despite the highly variable orientation of the fractures and faults, the fast polarization direction of the shear waves is very consistent with the direction of maximum horizontal compression determined from wellbore breakouts and drilling induced tensile fractures. At least three major shear zones were intersected by the borehole that are characterized by anomalously low velocity and resistivity, anomalously high shear velocity anisotropy and an absence of stress-induced wellbore breakouts (which suggests anomalously low differential stress). We argue that the physical mechanism responsible for the seismic velocity anisotropy observed in the Pilot Hole is the preferential closure of fractures in response to an anisotropic stress state. Copyright 2004 by the American Geophysical Union. 2004 English 00948276 10.1029/2003GL019020 Geophysical Research Letters 31 L15S17 1-4 Department of Geophysics, Stanford University, Stanford, CA, United States 15 Drilling; Electromagnetic wave polarization; Fracture; Granite; Magnetic anisotropy; Seismic prospecting, Pilot holes; Shear velocity; Wellbores, Boreholes, borehole geophysics; in situ stress; physical property; San Andreas Fault; seismic anisotropy; seismic velocity, California; North America; Parkfield; United States; Western Hemisphere; World https://www.scopus.com/inward/record.uri?eid=2-s2.0-5144225952&doi=10.1029%2f2003GL019020&partnerID=40&md5=445ece89cf56d552cf799565ddc6a7d1 cited By 125 N.L. Boness M.D. Zoback article Hickman2004 Borehole breakouts and drilling-induced tensile fractures in the 2.2-km-deep SAFOD pilot hole at Parkfield, CA, indicate significant local variations in the direction of the maximum horizontal compressive stress, SHmax, but show a generalized increase in the angle between SHmax and the San Andreas Fault with depth. This angle ranges from a minimum of 25 ± 10° at 1000-1150 m to a maximum of 69 ± 14° at 2050-2200 m. The simultaneous occurrence of tensile fractures and borehole breakouts indicates a transitional strike-slip to reverse faulting stress regime with high horizontal differential stress, although there is considerable uncertainty in our estimates of horizontal stress magnitudes. If stress observations near the bottom of the pilot hole are representative of stresses acting at greater depth, then they are consistent with regional stress field indicators and an anomalously weak San Andreas Fault in an otherwise strong crust. Copyright 2004 by the American Geophysical Union. 2004 English 00948276 10.1029/2004GL020043 Geophysical Research Letters 31 L15S12 1-4 U.S. Geological Survey, 345 Middlefield Road, Menlo Park, CA 94025, United States; Department of Geophysics, Stanford University, Stanford, CA, United States 15 Compressive stress; Drilling; Fracture; Geophysical prospecting; Stress analysis, Borehole breakouts; Pilot holes; Stress fields; Stress orientations, Boreholes, borehole geophysics; in situ stress; orientation; San Andreas Fault; stress measurement, California; North America; Parkfield; United States; Western Hemisphere; World https://www.scopus.com/inward/record.uri?eid=2-s2.0-7044264976&doi=10.1029%2f2004GL020043&partnerID=40&md5=a9c00d9e3b3d52667207dd81f11084ab cited By 204 S. Hickman M. Zoback article Bell20041089 Seismic data across the offshore half of the Chicxulub impact crater reveal a 145 km-diameter post-impact basin to be a thickening of Tertiary sediment, which thickens by ∼0.7 sec from the basin margin to the basin center. The basin existed long after the impact and was gradually infilled to its current flat surface. A suite of seismic horizons within the impact basin have been picked on four reflection lines across the crater. They reveal that the western and northwestern parts of the impact basin were filled first. Subsequently, there was a dramatic change in the depositional environment, indicated by an unconformable surface that can be mapped across the entire basin..A prograding shelf sequence downlaps onto this unconformity in the eastern basin. The seismic stratigraphic relationships suggest a marine regression, with sedimentation becoming gradually more passive as sediments fill the eastern part of the impact basin. The central and northeastern parts of the basin are filled last. The onshore hole Yaxcopoil-1 (Yax-1), which was drilled on the flanks of the southern basin, has been projected onto the offshore seismic data to the west of the crater center. Using dates obtained from this onshore well and regional data, approximate ages have been placed on the most significant horizons in the offshore seismic data. Our preliminary interpretation is that the western and northwestern basins were almost entirely filled by 40 Ma and that the marine regression observed in the eastern basin is early Miocene in age. Offshore seismic stratigraphic analyses and onshore data within Yax-1 suggest that the early Paleocene is highly attenuated across the impact basin. The Mesozoic section appears to be €1 km thicker offshore than onshore. We calculate that, given this offshore thickening, the volume of Mesozoic rocks that have been excavated, melted, or vaporized during impact is around 15% larger than expected from calculations that assume the offshore thickness is equal to that onshore. This has significant consequences for any environmental calculations. The current offset between the K-T boundary outside and inside the crater is ∼700 m. However, infilling of basins with sediments is usually accompanied by subsidence, and immediately following the impact, the difference would have been smaller. We calculate the original topographic offset on the K-T boundary to have been between 450 and 700 m, which is in agreement with depth-diameter scaling laws for a mixed target. © Meteoritical Society, 2004. 2004 10.1111/j.1945-5100.2004.tb01130.x Meteoritics and Planetary Science 39 1089-1098 Department of Earth Science/Eng., Imperial College, London SW7 2AZ, United Kingdom; Department of Geology/Geological Eng, Colorado School of Mines, Colorado 80401, United States 7 https://www.scopus.com/inward/record.uri?eid=2-s2.0-3943056939&doi=10.1111%2fj.1945-5100.2004.tb01130.x&partnerID=40&md5=2d7b3c7a28700c05208022829a65c4e9 cited By 33 C. Bell J.V. Morgan G.J. Hampson B. Trudgill article Ames20041145 The 65 Ma Chicxulub impact crater formed in the shallow coastal marine shelf of the Yucatán Platform in Mexico. Impacts into water-rich environments provide heat and geological structures that generate and focus sub-seafloor convective hydrothermal systems. Core from the Yaxcopoil-1 (Yax-1) hole, drilled by the Chicxulub Scientific Drilling Project (CSDP), allowed testing for the presence of an impact-induced hydrothermal system by: a) characterizing the secondary alteration of the 100 m-thick impactite sequence; and b) testing for a chemical input into the lower Tertiary sediments that would reflect aquagene hydrothermal plume deposition. Interaction of the Yax-1 impactites with seawater is evident through redeposition of the suevites (unit 1), secondary alteration mineral assemblages, and the subaqueous depositional environment for the lower Tertiary carbonates immediately overlying the impactites. The least-altered silicate melt composition intersected in Yax-1 is that of a calc-alkaline basaltic andesite with 53.4-56 wt% SiO2 (volatile-free). The primary mineralogy consists of fine microlites of diopside, plagioclase (mainly Ab 47), ternary feldspar (Ab 37 to 77), and trace apatite, titanite, and zircon. The overprinting alteration mineral assemblage is characterized by Mg-saponite, K-montmorillonite, celadonite, K-feldspar, albite, Fe-oxides, and late Ca and Mg carbonates. Mg and K metasomatism resulted from seawater interaction with the suevitic rocks producing smectite-K-feldspar assemblages in the absence of any mixed layer clay minerals, illite, or chlorite. Rare pyrite, sphalerite, galena, and chalcopyrite occur near t he base of the impactites. These secondary alteration minerals formed by low temperature (0-150 °C) oxidation and fixation of alkalis due to the interaction of glass-rich suevite with down-welling seawater in the outer annular trough intersected at Yax-1. The alteration represents a cold, Mg-K-rich seawater recharge zone, possibly recharging higher temperature hydrothermal activity proposed in the central impact basin. Hydrothermal metal input into the Tertiary ocean is shown by elevated Ni, Ag, Au, Bi, and Te concentrations in marcasite and Cd and Ga in sphalerite in the basal 25 m of the Tertiary carbonates in Yax-1. The lower Tertiary trace element signature reflects hydrothermal metal remobilization from a mafic source rock and is indicative of hydrothermal venting of evolved seawater into the Tertiary ocean from an impact-generated hydrothermal convective system. © Meteoritical Society, 2004. Printed in USA. 2004 10.1111/j.1945-5100.2004.tb01134.x Meteoritics and Planetary Science 39 1145-1167 Natural Resources Canada, Geological Survey of Canada, 601 Booth Street, Ottawa, Ont. K1A 0E8, Canada; Mineralogical Consultant, 15 Scotia Place, Ottawa, Ont. K1S 0W2, Canada; Geo Eco Arc Research, 16305 St Mary's Church Road, Aquasco, MD 20608, United States; Lunar and Planet Science Inst., Houston, TX 77058, United States 7 https://www.scopus.com/inward/record.uri?eid=2-s2.0-3943104871&doi=10.1111%2fj.1945-5100.2004.tb01134.x&partnerID=40&md5=55f7d4e441994ef03b425146cf6d6fb3 cited By 37 D.E. Ames I.M. Kjarsgaard K.O. Pope B. Dressler M. Pilkington article Haskins2004162 The Ko'olau Scientific Drilling Project (KSDP) was initiated to determine if the distinctive geochemistry of Ko'olau lavas is a near-surface feature. This project successfully deepened a recent, ∼351 m deep, tri-cone rotary-drilled water well by coring another ∼328 m. Three Ar-Ar plateau ages of 2.8 to 2.9 Ma from the drill core section of 103 flows confirm stratigraphic interpretations that core drilling recovered the deepest and oldest subaerially erupted lavas yet sampled from this volcano. The petrography and geochemistry of the core, and cuttings from this and another new Ko'olau water well (∼433 m deep) were determined. These analyses revealed that the geochemically distinct lavas of Ko'olau form a veneer only 175-250 in thick at the drill sites, covering flows with more typical Hawaiian tholeiite compositions. The compositional change occurred near the end of shield volcanism and is not abrupt. Thus, it is probably not related to a catastrophic event such as the collapse of the northeast flank of this volcano. The distinct geochemistry of surface Ko'olau lavas cannot be explained by melting pyroxenitic or combined pyroxenitic and peridotitic sources. Additional recycled oceanic crustal components, such as plagioclase-rich cumulates and sediment, were probably involved. As the Ko'olau volcano drifted off the Hawaiian hotspot and the overall degree of melting decreased, the proportion of melts from recycled oceanic crustal material increased relative to those from mantle peridotite. © Springer-Verlag 2004. 2004 English 00107999 10.1007/s00410-003-0546-y Contributions to Mineralogy and Petrology 147 162-188 Department of Geology and Geophysics, University of Hawai'i, 1680 East-West Road, Honolulu, HI 96822, United States 2 geochemistry; lava; petrography; volcanic rock, Hawaii [United States]; North America; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-2342445383&doi=10.1007%2fs00410-003-0546-y&partnerID=40&md5=7dd285442cb4679b2b285aff913b0a99 cited By 52 E.H. Haskins M.O. Garcia article Li2004 We used dense linear seismic arrays across and along the San Andreas Fault (SAF) at Parkfield, California to record fault zone trapped waves generated by explosions and microearthquakes in 2002. Prominent trapped waves appeared at stations close to the SAF main fault trace while some energy was trapped in the north strand at the array site. Observations and 3-D finite-difference simulations of trapped waves at 2-5 Hz show evidence of a damaged core zone on the main SAF. The zone from the surface to seismogenic depths is marked by a low-velocity waveguide ∼150 m wide, in which Q is 10-50 and shear velocities are reduced by 30-40% from wall-rock velocities, with the greatest velocity reduction at shallow depth. We interpret that this distinct low-velocity zone on the main SAF is a remanent of damage due to past large earthquakes on the principal fault plane at Parkfield. A less-developed low-velocity zone may be evident on the north strand that experienced minor breaks in the 1966 M6 event. Copyright 2004 by the American Geophysical Union. 2004 English 00948276 10.1029/2003GL019044 Geophysical Research Letters 31 L12S06 1-5 Department of Earth Sciences, University of Southern California, Los Angeles, CA 90089, United States; Institute of Geophys./Planetary Phys, University of California, Los Angeles, CA 90095, United States 12 Computer simulation; Earthquakes; Finite difference method; Structural analysis; Velocity; Waveguides; Strike-slip faults; Velocity; Water waves, Fault zones; Seismic arrays; Trapped waves; Velocity reduction, Seismology; Shear flow, low velocity zone; San Andreas Fault; seismic velocity; trapped wave, California; North America; Parkfield; United States, Damaged structures; Fault-zone trapped waves; Finite difference simulations; Large earthquakes; Linear seismic array; Low velocity zones; Micro-earthquakes; San Andreas fault https://www.scopus.com/inward/record.uri?eid=2-s2.0-6044248858&doi=10.1029%2f2003GL019044&partnerID=40&md5=79f2cc7bbb511d07eb6333915e93de89 cited By 100 Y.-G. Li J.E. Vidale E.S. Cochran article Williams2004 Detailed thermal measurements have been acquired in the 2.2-km-deep SAFOD pilot hole, located 1.8 km west of the SAF near Parkfield, California. Heat flow from the basement section of the borehole (770 to 2160 m) is 91 mW m-2, higher than the published 74 mW m -2 average for the Parkfield area. Within the resolution of the measurements, heat flow is constant across faults that intersect the borehole, suggesting that fluid flow does not alter the conductive thermal regime. Reanalysis of regional heat flow reveals an increase in heat flow along the SAF northwest of Parkfield. This transition corresponds to a shallowing base of seismicity and a change in fault behavior near the northern terminus of the M6 1966 Parkfield earthquake rupture. The persistence of elevated heat flow in the Coast Ranges to the west appears to rule out frictional heating on the SAF as the source of the SAFOD value. 2004 English 00948276 10.1029/2003GL019352 Geophysical Research Letters 31 L15S14 1-4 U.S. Geological Survey, 345 Middlefield Road, Menlo Park, CA 94025, United States; U.S. Geological Survey, Sacramento, CA 95819, United States 15 Earthquakes; Flow of fluids; Friction; Geophysical prospecting; Heating; Seismology; Thermal effects; Thermoanalysis, Heat flow; San Andreas Fault; Seismicity, Boreholes, borehole geophysics; heat flow; San Andreas Fault; strength, California; North America; Parkfield; United States; Western Hemisphere; World https://www.scopus.com/inward/record.uri?eid=2-s2.0-7044274675&doi=10.1029%2f2003GL019352&partnerID=40&md5=b8430912f3697dd5ee69d4ad7c7bf45e cited By 67 C.F. Williams F.V. Grubb S.P. Galanis Jr. article Roecker2004 Taking advantage of large datasets of both gravity and elastic wave arrival time observations available for the Parkfield, California region, we generated an image consistent with both types of data. Among a variety of strategies, the best result was obtained from a simultaneous inversion with a stability requirement that encouraged the perturbed model to remain close to a starting model consisting of a best fit to the arrival time data. The preferred model looks essentially the same as the best-fit arrival time model in areas where ray coverage is dense, with differences being greatest at shallow depths and near the edges of the model where ray paths are few. Earthquake locations change by no more than about 100 m, the general effect being migration of the seismic zone to the northeast, closer to the surface trace of the San Andreas Fault. Copyright 2004 by the American Geophysical Union. 2004 English 00948276 10.1029/2003GL019396 Geophysical Research Letters 31 L12S041-4 Department of Earth/Environ. Sci., Rensselaer Polytechnic Institute, 110 8th Street, Troy, NY 12180-3590, United States; Department of Geology and Geophysics, University of Wisconsin-Madison, 1215 West Dayton St., Madison, WI 53706, United States; U.S. Geological Survey, 345 Middlefield Rd., Menlo Park, CA 94025, United States 12 Drilling; Earthquakes; Gravitational effects; Mathematical models; Perturbation techniques; Seismology; Site selection; Earthquakes; Strike-slip faults, Best-fit arrival time model; Datasets; Seismic zones, Elastic waves; Elastic waves, earthquake hypocenter; elastic wave; gravity survey; modeling; San Andreas Fault; seismic hazard, California; North America; Parkfield; United States, Arrival-time data; Earthquake location; Hypocenter location; Joint inversion; Large datasets; San Andreas fault; Shallow depths; Surface traces https://www.scopus.com/inward/record.uri?eid=2-s2.0-6044257846&doi=10.1029%2f2003GL019396&partnerID=40&md5=6901919967e545c52d4f6415199643d5 cited By 69 S. Roecker C. Thurber D. McPhee article Rhodes2004 This paper presents major and trace element compositions oflavas from the entire 3098 m stratigraphic section sampled by phase-2 of the Hawaii Scientific Drilling Project. The upper 245 m are lavas from Mauna Loa volcano, and the lower 2853 m are lavas and volcanoclastic rocks from Mauna Kea volcano. These intervals are inferred to represent about 100 ka and 400 ka respectively of the eruptive history of the two volcanoes. The Mauna Loa tholeiites tend to be higher in SiO2 and lower in total iron, TiO2, alkalis, and incompatible elements at a given MgO content than Mauna Kea lavas. The transition from Mauna Loa to Mauna Kea lavas is all the more pronounced because the Mauna Loa tholeiites overlie a thin sequence of postshield Mauna Kea alkalic to transitional tholeiitic lavas. The Mauna Loa tholeiites display well- developed coherent trends with MgO that are indistinguishable in most respects from modern lavas. With depth, however, there is a slight decline in incompatible element abundances, and small shifts to depleted isotopic ratios. These characteristics suggest small changes in melt production and source components over time, superimposed on shallow melt segregation. The Mauna Kea section is subdivided into a thin, upper 107 m sequence of postshield tholeiites, transitional tholeiites and alkali basalts of the Hamakua volcanics, overlying four tholeiitic magma types that are intercalated throughout the rest of the core. These four magma types are recognized on the basis of MgO-normalized SiO2 and Zr/Nb values. Type-1 lavas (high SiO 2 and Zr/Nb) are ubiquitous below the postshield lavas and are the dominant magma type on Mauna Kea. They are inter-layered with the other three lava types. Type-2 lavas (low SiO2 but high Zr/Nb) are found only in the upper core, and especially above 850 m. Type-3 lavas (low SiO2 and Zr/Nb) are very similar to tholeiites from Loihi volcano and are present only below 1974 m. There are only 3 discrete samples of type-4 lavas (high SiO2 and low Zr/Nb), which are present in the upper and lower core. The differences between these magma types are inferred to reflect changes in melt production, depth of melt segregation, and differences in plume source components over about 400 ka of Mauna Kea's eruptive history. At the start of this record, eruption rates were high, and two distinct tholeiitic magmas (type-1 and 3) were erupting concurrently. These two magmas require two distinct source components, one similar to that of modern Loihi tholeiites and the other close to that of Kilauea magmas. Subsequently, the Loihi- like source of the type-3 magmas was exhausted, and these lavas are absent from the remainder of the core. For the next 200 ka or so, the eruptive sequence consists of inter-layered type-1 and -2 lavas that are derived from a common Mauna Kea source, the major difference between the two being the depth at which the melts segregated from the source. At around 440 ka (corresponding with the transition in the core from submarine to subaerial lavas) eruption rates began to decline and low-MgO lavas are suddenly much more abundant in the record. Continuing gradual decline in melting and eruption rates was accompanied by a decline in normalized SiO2 content of the type-1 magmas, and the eventual onset of postshield magmatism. Copyright 2004 by the American Geophysical Union. Article 2004 English 15252027 10.1029/2002GC000434 Geochemistry, Geophysics, Geosystems 5 3 https://www.scopus.com/inward/record.uri?eid=2-s2.0-34249790169&doi=10.1029%2f2002GC000434&partnerID=40&md5=db50868a981f434eda344354f4b635b6 Cited by: 146; All Open Access, Bronze Open Access J.M. Rhodes M.J. Vollinger article Cornet2004395 The 1000 m-deep AIG10 borehole intersects the Aigion Fault within the limestone of the Pindos nappe at 760 m. It has demonstrated that the fault is dipping 60° with respect to horizontal, an angle consistent with the strength characteristics of the fault material as determined in the laboratory. It does not seem to be listric, as suggested by the location of superficial microseismic events. The fault is about 7 m thick, with a 50 cm core of clay derived from smeared radiolarite formation. The fault offsets the basement rock by 150±20 m and constitutes a hydraulic barrier that sustains a 0.5 MPa differential pressure. Below the fault, a strongly karstified limestone has been encountered down to 1000 m. It is the site of a 0.9 MPa overpressure and exhibits no temperature gradient. Water geochemistry demonstrates the continental origin of this significant flow, which obliterates the regional heat flux. The present monitoring of downhole pressure yields data on tidal variations with a resolution of 1/500 as well as pressure variations induced by teleseisms. Given preliminary results from 14C dating, the age of the fault is about 50 kyr and the mean slip rate equal about 3.5 mm yr-1. © 2004 Académie des sciences. Published by Elsevier SAS. All rights reserved. Article 2004 French 16310713 10.1016/j.crte.2004.02.002 Comptes Rendus - Geoscience 336 395 – 406 4-5 Gulf of Corinth; Ionian Sea; Mediterranean Sea; active fault; dip; fault plane; fluid flow; hydrogeochemistry; rift zone https://www.scopus.com/inward/record.uri?eid=2-s2.0-1942473545&doi=10.1016%2fj.crte.2004.02.002&partnerID=40&md5=c572aaf90cf05aa6d8963c58882e2257 Cited by: 61 François Cornet Mai Linh Doan Isabelle Moretti Günter Borm article Sanford2004 2004 English 00963941 10.1029/2004EO390001 Eos 85 American Geophysical Union 369+377 Self-Trail, USGS., Reston, VA, United States; USGS., Lakewood, CO, United States 39 https://www.scopus.com/inward/record.uri?eid=2-s2.0-33646456831&doi=10.1029%2f2004EO390001&partnerID=40&md5=5f5a91690e137aac3373df5bb4806c14 cited By 23 W.E. Sanford G.S. Gohn D.S. Powars J.W. Horton Jr. L.E. Edwards M. Jean R.H. Morin article Watanabe20042323 To detect the change of physical properties in small areas, a series of high-resolution waveform inversions is applied to time-lapse seismic data. A procedure by use of differentiation between the time-lapse data and normalization using reference data is proposed in this study. The procedure is derived as a straight-forward extension of waveform inversion as the scatterer imaging. Through numerical tests, the proposed approach was found to be more accurate than the conventional approach in obtaining the velocity change in small areas. The method was applied to the time-lapse crosswell seismic data obtained during the Mallik 2002 gas production test. A small area showing a velocity decrease near the production zone were found using the proposed method, indicating the existence of dissociated methane gas in the sand layers. © 2004 Society of Exploration Geophysicists. 2004 English 10523812 10.1190/1.1845221 SEG Technical Program Expanded Abstracts 23 Society of Exploration Geophysicists 2323-2326 Nagoya University, Japan; Japan Petroleum Exploration Co., Ltd, Japan; JGI, Inc, Japan; Kyoto University, Japan 1 Geophysical prospecting; Petroleum prospecting; Seismic response; Seismic waves; Waveform analysis, Conventional approach; Gas production test; Gas-hydrate production; Numerical tests; Production zones; Time-lapse seismic data; Velocity changes; Waveform inversion, Gas hydrates https://www.scopus.com/inward/record.uri?eid=2-s2.0-55849128984&doi=10.1190%2f1.1845221&partnerID=40&md5=b1902cbf1429d2249c4a7392db321581 cited By 74 T. Watanabe S. Shimizu E. Asakawa T. Matsuoka article Oye2004 In August 2002, an array of 32 three-component geophones was installed in the San Andreas Fault Observatory at Depth (SAFOD) Pilot Hole (PH) at Parkfield, CA. As an independent test of surface-observation-based microearthquake locations, we have located such events using only data recorded on the PH array. We then compared these locations with locations from a combined set of PH and Parkfield High Resolution Seismic Network (HRSN) observations. We determined the uncertainties in the locations as they relate to errors in the travel time picks and the velocity model by the bootstrap method. Based on the PH and combined locations, we find that the "C2" cluster to the northeast of the PH has the smallest location uncertainties. Events in this cluster also have the most similar waveforms and largest magnitudes. This confirms earlier suggestions that the C2 cluster is a promising target for the SAFOD Main Hole. Copyright 2004 by the American Geophysical Union. 2004 English 00948276 10.1029/2003GL019403 Geophysical Research Letters 31 L12S10 1-5 NORSAR, Instituttveien 25, Kjeller N-2007, Norway; Division of Earth and Ocean Sciences, Duke University, Durham, NC 27708, United States 12 Data acquisition; Earthquakes; Error analysis; Mathematical models; Observatories; Waveform analysis; Seismology; Strike-slip faults, Bootstrap method; High resolution seismic network (HRSN); Microearthquakes; Pilot hole (PH), Geophysics; Location, earthquake hypocenter; microtremor; San Andreas Fault; seismic method, Bootstrap method; High resolution seismic; Location uncertainty; San Andreas fault; Seismic arrays; Surface observation; Three component; Velocity model https://www.scopus.com/inward/record.uri?eid=2-s2.0-6044250185&doi=10.1029%2f2003GL019403&partnerID=40&md5=995a01754f523a4e29311afca7cdf301 cited By 17 V. Oye J.A. Chavarria article Nadeau2004 Large numbers of small earthquakes recorded over 2 decades and analyzed with advanced techniques are used to characterize the detailed kinematics, structure and recurrence interval scaling properties of micro-seismicity in a 4 × 4 km lateral and 6 km deep crustal volume encompassing the region of the SAFOD deep drilling experiment. The characterization reveals that the seismically active San Andreas fault in the vicinity of SAFOD's repeating magnitude 2 target earthquakes is composed of two sub-parallel fault strands that are creeping at comparable rates and that one of the strands lies between the SAFOD drilling platform and SAFOD's target events. In the region, ∼55% of the earthquakes are members of 52 characteristically repeating earthquake sequences. The recurrence intervals of the repeating target events are consistent with the interval scaling of the other sequences. However this. scaling is contrary to that expected from standard constant stress-drop theory. Copyright 2004 by the American Geophysical Union. 2004 English 00948276 10.1029/2003GL019409 Geophysical Research Letters 31 L12S08 1-4 Berkeley Seismological Laboratory, University of California, Berkeley, CA 94720, United States; Ist. Naz di Geofisica Vulcanologia, Rome, Italy 12 Creep; Geophysics; Kinematics; Seismology; Stresses; Structural analysis; Theory; Drilling platforms; Faulting; Geophysics; Kinematics; Strike-slip faults; Tectonics, Crustal volume; Micro-seismicity; Scaling properties; Stress-drop theory, Earthquakes; Earthquakes, deep drilling; earthquake recurrence; kinematics; microtremor; San Andreas Fault; seismicity, California; North America; United States, Constant stress; Fault strands; Recurrence intervals; Repeating earthquake; San Andreas fault; Scaling properties; Small earthquakes; Target regions https://www.scopus.com/inward/record.uri?eid=2-s2.0-6044269252&doi=10.1029%2f2003GL019409&partnerID=40&md5=f382c4ea9603d48e2488701cb8fb7190 cited By 50 R.M. Nadeau A. Michelini R.A. Uhrhammer D. Dolenc T.V. McEvilly article McPhee2004 We present newly compiled magnetic, gravity, and geologic datasets from the Parkfield region around the San Andreas Fault Observatory at Depth (SAFOD) pilot hole in order to help define the structure and geophysical setting of the San Andreas Fault (SAF). A 2-D cross section of the SAF zone at SAFOD, based on new, tightly spaced magnetic and gravity observations and surface geology, shows that as drilling proceeds NE toward the SAF, it is likely that at least 2 fault bounded magnetic slivers, possibly consisting of magnetic granitic rock, serpentinite, or unusually magnetic sandstone, will be encountered. The upper 2 km of the model is constrained by an order of magnitude increase in magnetic susceptibility at 1400 m depth observed in pilot hole measurements. NE of the SAF, a flat lying, tabular body of serpentinite at 2 km depth separates two masses of Franciscan rock and truncates against the SAF. 2004 English 00948276 10.1029/2004GL019363 Geophysical Research Letters 31 L12S03 1-4 U.S. Geological Survey, 345 Middlefield Road, Menlo Park, CA 94025, United States 12 Data acquisition; Granite; Gravitational effects; Magnetic materials; Magnetic susceptibility; Mathematical models; Rock drilling; Rocks; Sandstone; Serpentine; Magnetic susceptibility; Magnetism; Rock drilling; Strike-slip faults, Crustal structure; Magnetic granitic rock; San Andreas Fault (SAF); Surface geology, Geology; Structural geology, crustal structure; geological mapping; gravity survey; magnetic survey; San Andreas Fault; serpentinite, Crustal structure; Granitic rocks; Pilot holes; Potential field; San Andreas fault; Serpentinite https://www.scopus.com/inward/record.uri?eid=2-s2.0-6044248859&doi=10.1029%2f2004GL019363&partnerID=40&md5=d295a82a0c6ab7778f2f244c68e980a2 cited By 60 D.K. McPhee R.C. Jachens C.M. Wentworth article Poag200422 In July 1983, the shipboard scientists of Deep Sea Drilling Project Leg 95 found an unexpected bonus in a core taken 150 kilometers east of Atlantic City, N.J. At Site 612, the scientists recovered a 10-centimeter-thick layer of late Eocene debris ejected from an impact about 36 million years ago. Microfossils and argon isotope ratios from the same layer reveal that the ejecta were part of a broad North American impact debris field, previously known primarily from the Gulf of Mexico and Caribbean Sea. Since that serendipitous beginning, years of seismic reflection profiling, gravity measurements and core drilling have confirmed the source of that strewn field - the Chesapeake Bay impact crater, the largest structure of its kind in the United States, and the sixth-largest impact crater on Earth. 2004 English 00168556 Geotimes 49 22-25 U.S. Geological Survey, Woods Hole, MA, United States 1 crater; ejecta; Eocene; impact structure; sediment core, Chesapeake Bay; North America; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-1642278797&partnerID=40&md5=08d22c04a2309e14dac09471ec786a42 cited By 1 C.W. Poag article Smit20041113 The transition from impact to post-impact rocks in the Yaxcopoil-1 (Yax-1) core is marked by a 2 cm-thick clay layer characterized by dissolution features. The clay overlies a 9 cm-thick hardground, overlying a 66 cm-thick crossbedded unit, consisting of dolomite sandstone alternating with thin micro-conglomerates layers with litho- and bioclasts and the altered remains of impact glass, now smectite. The micro-conglomerates mark erosion surfaces. Microprobe and backscatter SEM analysis of the dolomite rhombs show an early diagenetic, complex-zoned, idiomorphic overgrowth, with Mn-rich zones, possibly formed by hot fluids related to cooling melt sheet in the crater. The pore spaces are filled with several generations of coelestite, barite, K-feldpar, and sparry calcite. XRF core scanning analysis detected high Mn values in the crossbedded sediments but no anomalous enrichment of the siderophile elements Cr, Co, Fe, and Ni in the clay layer. Shocked quartz occurs in the crossbedded unit but is absent in the clay layer. The basal Paleocene marls are strongly dissolved and do not contain a basal Paleocene fauna. The presence of a hardground, the lack of siderophile elements, shocked quartz, or Ni-rich spinels in the clay layer, and the absence of basal Paleocene biozones PO and Pa all suggest that the top of the ejecta sequence and a significant part of the lower Paleocene is missing. Due to the high energy sedimentation infill, a hiatus at the top of the impactite is not unexpected, but there is nothing in the biostratigraphy, geochemistry, and petrology of the Yax-1 core that can be used to argue against the synchroneity of the end-Cretaceous mass-extinctions and the Chicxulub crater. © Meteoritical Society, 2004. 2004 10.1111/j.1945-5100.2004.tb01132.x Meteoritics and Planetary Science 39 1113-1126 Faculty of Earth and Life Sciences, Vrije Universiteit, de Boelaan 1085, Amsterdam HV 1081, Netherlands; NIOZ, P.O. Box 59, Texel, Den Burg AB NL-1790, Netherlands 7 https://www.scopus.com/inward/record.uri?eid=2-s2.0-3943099405&doi=10.1111%2fj.1945-5100.2004.tb01132.x&partnerID=40&md5=a8d32210e24b3aeef1ac16617ef3a559 cited By 40 J. Smit S. Van Der Gaast W. Lustenhouwer article Hecht20041169 Petrographical and chemical analysis of melt particles and alteration minerals of the about 100 m-thick suevitic sequence at the Chicxulub Yax-1 drill core was performed. The aim of this study is to determine the composition of the impact melt, the variation between different types of melt particles, and the effects of post-impact hydrothermal alteration. We demonstrate that the compositional variation between melt particles of the suevitic rocks is the result of both incomplete homogenization of the target lithologies during impact and subsequent post-impact hydrothermal alteration. Most melt particles are andesitic in composition. Clinopyroxene-rich melt particles possess lower SiO2 and higher CaO contents. These are interpreted by mixing of melts from the silicate basement with overlying carbonate rocks. Multi-stage post-impact hydrothermal alteration involved significant mass transfer of most major elements and caused further compositional heterogeneity between melt particles. Following backwash of seawater into the crater, palagonitization of glassy melt particles likely caused depletion of SiO2, A12O3, CaO, Na2O, and enrichment of K2O and FeOtot during an early alteration stage. Since glass is very susceptible to fluid-rock interaction, the state of primary crystallization of the melt particles had a significant influence on the intensity of the post-impact hydrothermal mass transfer and was more pronounced in glassy melt particles than in well-crystallized particles. In contrast to other occurrences of Chicxulub impactites, the Yax-1 suevitic rocks show strong potassium metasomatism with hydrothermal K-feldspar formation and whole rock K2O enrichment, especially in the lower unit of the suevitic sequence. A late stage of hydrothermal alteration is characterized by precipitation of silica, analcime, and Na-bearing Mg-rich smectite, among other minerals. This indicates a general evolution from a silica-undersaturated fluid at relatively high potassium activities at an early stage toward a silica-oversaturated fluid at relatively high sodium activities at later stages in the course of fluid rock interaction. © Meteoritical Society, 2004. Printed in USA. 2004 10.1111/j.1945-5100.2004.tb01135.x Meteoritics and Planetary Science 39 1169-1186 Institut für Mineralogie, Museum für Naturkunde, Humboldt-Universität zu Berlin, Invalidenstrasse 43, Berlin D-10115, Germany 7 https://www.scopus.com/inward/record.uri?eid=2-s2.0-3943087085&doi=10.1111%2fj.1945-5100.2004.tb01135.x&partnerID=40&md5=4f9af36fad91b1b9d7b9217ea1308ba7 cited By 59 L. Hecht A. Wittmann R.-T. Schmitt D. Stöffler article Rowe20041223 Studies of large terrestrial impact craters indicate that post-impact hydrothermal activity is a likely consequence of the crustal deformation and heating induced by such events. In the case of the Chicxulub basin, where marine conditions were re-established soon after the impact, significant fluxing of seawater-through the crust and hydrothermal venting into the water column might be anticipated. We have carried out geochemical analyses of Tertiary carbonate sediments within the Yaxcopoil-1 (Yax-1) drill hole to test for evidence of such post-impact hydrothermal circulation. Hydrothermal activity is most likely to be found close to thick layers of melt rock inside the collapsed transient cavity, and it is estimated that Yax-1 is located ∼20 km outside this cavity. Consequently, the most likely signature of hydrothermal venting into the water column would be geochemical anomalies attributable to fallout of suspended particulate matter from a submarine hydrothermal plume. Samples of Tertiary biomicrites from depths of 794.01 to 777.02 m have high concentrations of manganese, iron, phosphorous, titanium, and aluminium and low iron/manganese ratios relative to samples from higher in the stratigraphic succession. This geochemical anomaly decreases' fairly systematically between 793.13 m and 777.02 m, above which an abrupt change in geochemistry is observed. A mass balance calculation suggests that the anomaly is unlikely to be the result of a decreasing detrital input to the carbonate sediments and the nature of the element enrichments is consistent with expectations for fallout from a distal hydrothermal plume. We conclude that a post-impact hydrothermal system did develop at Chicxulub, which led to the expulsion of hydrothermal fluids into the Tertiary water column. Preliminary biostratigraphic and magnetostratigraphic dating on Yax-1 core suggest that this hydrothermal activity lasted for at least 300 ka. © Meteoritical Society, 2004. Printed in USA. 2004 10.1111/j.1945-5100.2004.tb01138.x Meteoritics and Planetary Science 39 1223-1231 Department of Earth Science/Eng., Imperial College, London SW7 2AZ, United Kingdom 7 https://www.scopus.com/inward/record.uri?eid=2-s2.0-3943111707&doi=10.1111%2fj.1945-5100.2004.tb01138.x&partnerID=40&md5=04ae8d87f1d6c6a6316c03abbd2d6606 cited By 13 A.J. Rowe J.J. Wilkinson B.J. Coles J.V. Morgan article Chand2004573 The presence of gas hydrate in oceanic sediments is mostly identified by bottom-simulating reflectors (BSRs), reflection events with reversed polarity following the trend of the seafloor. Attempts to quantify the amount of gas hydrate present in oceanic sediments have been based mainly on the presence or absence of a BSR and its relative amplitude. Recent studies have shown that a BSR is not a necessary criterion for the presence of gas hydrates, but rather its presence depends on the type of sediments and the in situ conditions. The influence of hydrate on the physical properties of sediments overlying the BSR is determined by the elastic properties of their constituents and on sediment microstructure. In this context several approaches have been developed to predict the physical properties of sediments, and thereby quantify the amount of gas/gas hydrate present from observed deviations of these properties from those predicted for sediments without gas hydrate. We tested four models: the empirical weighted equation (WE); the three-phase effective-medium theory (TPEM); the three-phase Biot theory (TPB) and the differential effective-medium theory (DEM). We compared these models for a range of variables (porosity and clay content) using standard values for physical parameters. The comparison shows that all the models predict sediment properties comparable to field values except for the WE model at lower porosities and the TPB model at higher porosities. The models differ in the variation of velocity with porosity and clay content. The variation of velocity with hydrate saturation is also different, although the range is similar. We have used these models to predict velocities for field data sets from sediment sections with and without gas hydrates. The first is from the Mallik 2L-38 well, Mackenzie Delta, Canada, and the second is from Ocean Drilling Program (ODP) Leg 164 on Blake Ridge. Both data sets have Vp and Vs information along with the composition and porosity of the matrix. Models are considered successful if predictions from both Vp and Vs match hydrate saturations inferred from other data. Three of the models predict consistent hydrate saturations of 60-80 per cent from both Vp and Vs from log and vertical seismic profiling data for the Mallik 2L-38 well data set, but the TPEM model predicts 20 per cent higher saturations, as does the DEM model with a clay-water starting medium. For the clay-rich sediments of Blake Ridge, the DEM, TPEM and WE models predict 10-20 per cent hydrate saturation from Vp data, comparable to that inferred from resistivity data. The hydrate saturation predicted by the TPB model from Vp is higher. Using Vs data, the DEM and TPEM models predict very low or zero hydrate saturation while the TPB and WE models predict hydrate saturation very much higher than those predicted from Vp data. Low hydrate saturations are observed to have little effect on Vs. The hydrate phase appears to be connected within the sediment microstructure even at low saturations. © 2004 RAS. 2004 English 0956540X 10.1111/j.1365-246X.2004.02387.x Geophysical Journal International 159 573-590 School of Ocean and Earth Science, Southampton Oceanography Centre, European Way, Southampton SO14 3ZH, United Kingdom; Inst. Nazl. Oceanogr. Geofis. Sper., Borgo Grotta Gigante 42c, 34010 Sgonico, Trieste, Italy 2 comparative study; hydration; marine sediment; numerical model; P-wave; S-wave; saturation; seismic reflection; seismic survey; seismic velocity https://www.scopus.com/inward/record.uri?eid=2-s2.0-4644228964&doi=10.1111%2fj.1365-246X.2004.02387.x&partnerID=40&md5=f3cd7fba7a2b0880b803c900d1eca233 cited By 163 S. Chand T.A. Minshull D. Gei J.M. Carcione article Vermeesch20041019 The Chicxulub crater in Mexico is a nearly pristine example of a large impact crater. Its slow burial has left the central impact basin intact, within which there is an apparently uneroded topographic peak ring. Its burial, however, means that we must rely on drill holes and geophysical data to interpret the crater form. Interpretations of crater structures using geophysical data are often guided by numerical modeling and observations at other large terrestrial craters. However, such endeavors are hindered by uncertainties in current numerical models and the lack of any obvious progressive change in structure with increasing crater size. For this reason, proposed structural models across Chicxulub remain divergent, particularly within the central crater region, where the deepest well is only ∼1.6 km deep. The shape and precise location of the stratigraphic uplift are disputed. The spatial extent and distribution of the allogenic impact breccias and melt rocks remain unknown, as do the lithological nature of the peak ring and the mechanism for its formation. The objective of our research is to provide a well-constrained 3D structural and lithological model across the central region of the Chicxulub crater that is consistent with combined geophysical data sets and drill core samples. With this in mind, we present initial physical property measurements made on 18 core samples from the Yaxcopoil-1 (Yax-1) drill hole between 400 and 1500 m deep and present a new density model that is in agreement with both the 3D velocity and gravity data. Future collation of petrophysical and geochemical data from Yax-1 core, as well as further seismic surveys and drilling, will allow us to calibrate our geophysical models-assigning a suite of physical properties to each lithology. An accurate 3D model of Chicxulub is critical to our understanding of large craters and to the constraining of the environmental effects of this impact. © Meteoritical Society, 2004. Printed in USA. 2004 10.1111/j.1945-5100.2004.tb01127.x Meteoritics and Planetary Science 39 1019-1034 Department of Earth Science/Eng., Imperial College, London SW7 2AZ, United Kingdom 7 https://www.scopus.com/inward/record.uri?eid=2-s2.0-3943072494&doi=10.1111%2fj.1945-5100.2004.tb01127.x&partnerID=40&md5=d5d78f1b1961014bc441408dc52bbe3d cited By 38 P.M. Vermeesch J.V. Morgan article Helm-Clark20043 This paper concerns the interpretation of borehole geophysical data from basalt sequences, especially continental basalt sequences that host aquifers. Based on modifications of the rules used for interpreting borehole data from sedimentary rocks, new rules are proposed to identify the internal stratigraphy, aquifer boundaries, and alteration features in continental basalts.The value of several wireline tools is critiqued. Natural gamma logs have limited utility in basalt sequences unless anomalously high-potassium or low-potassium basalt flows and/or sedimentary interbeds exist which can act as marker beds for stratigraphic correlations. Neutron logs can usually discriminate between individual flows, flow breaks and interbeds, even in unsaturated basalts. Neutron logs and temperature logs can also be used to map aquifer thickness in basalt. Gamma-gamma density logs are usually sensitive to the density contrasts between interbeds and basalt flows, and in combination with neutron and natural gamma logs are crucial for the correct interpretation of large void spaces in basalt such as collapsed lava tubes and formerly inflated pahoehoe lobes. Basalt porosity calculated from neutron, resistivity and/or gamma-gamma density logs is commonly overestimated due to the presence of hydrous alteration minerals. Velocity and resistivity logs are best at discriminating between flows in saturated conditions. Magnetic susceptibility logs may capture magnetic mineralogy variations at a finer scale than that of flows and flow breaks and therefore should always be interpreted in combination with other logs. Non-spectral neutron-gamma logs are not useful in basalt, though spectral neutron-gamma logs have been used successfully for stratigraphic correlation and to locate pollutants. Geochemical logs or the inclination of magnetic remanence provide the best data to discriminate individual flows with a basalt sequence, and thus establish an internal stratigraphy. Other tools used alone cannot provide reliable stratigraphic information, but a combination of tools may work. We recommend the combination of natural gamma, neutron, and gamma-gamma density logs in unsaturated rocks, and these logs plus velocity and resistivity logs in saturated rocks. © 2003 Published by Elsevier B.V. 2004 English 09269851 10.1016/j.jappgeo.2003.06.003 Journal of Applied Geophysics 55 Elsevier 3-38 Department of Geosciences, Idaho State University, Pocatello, ID 83209-8072, United States; Idaho Natl. Eng./Environ.Lab., P.O. Box 1625, Idaho Falls, ID 83415, United States 1-2 Aquifers; Basalt; Boreholes; Magnetic susceptibility; Remanence; Sedimentary rocks, Magnetic mineralogy, Stratigraphy, aquifer; basalt; borehole geophysics; groundwater exploration; mineral alteration; stratigraphy https://www.scopus.com/inward/record.uri?eid=2-s2.0-0347682435&doi=10.1016%2fj.jappgeo.2003.06.003&partnerID=40&md5=65487e77453c2974052bc7941a93dd95 cited By 40 C.M. Helm-Clark D.W. Rodgers R.P. Smith article Alegret200459 Sediments recovered at lower bathyal ODP Site 1049 on Blake Nose (Northwestern Atlantic) offer an opportunity to study environmental changes at the Cretaceous/Paleogene (K/P) boundary relatively close to the Chicxulub impact structure on the Yucatan peninsula, Mexico. In Hole 1049C, the boundary is located at the base of a 9-cm-thick layer with abundant spherules, considered to be impact ejecta. Uppermost Maastrichtian oozes below, and lowermost Danian pelagic oozes above the spherule-bed contain well-preserved bathyal benthic foraminifera. The spherule-bed itself, in contrast, contains a mixture of shallow (neritic) and deeper (bathyal) species, and specimens vary strongly in preservation. This assemblage was probably formed by reworking and down-slope transport triggered by the K/P impact. Across the spherule-bed (i.e., the K/P boundary) only ∼7% of benthic foraminiferal species became extinct, similar to the low extinction rates of benthic foraminifera worldwide. Quantitative analysis of benthic foraminiferal assemblages and morphogroups in the >63-μm size fraction indicates a relatively eutrophic, stable environment during the latest Maastrichtian, interrupted by a sudden decrease in the food supply to the benthos at the K/P boundary and a decrease in diversity of the faunas, followed by a stepped recovery during the earliest Danian. The recovery was probably linked to the gradual recovery of surface-dwelling primary producers. © 2004 Elsevier B.V. All rights reserved. 2004 10.1016/j.palaeo.2004.02.028 Palaeogeography, Palaeoclimatology, Palaeoecology 208 59-83 Department of Earth Sciences, University College London, London WC1E-6BT, United Kingdom; Dept. of Earth and Environ. Sciences, Wesleyan University, Middletown, CT 06459-0139, United States; Department of Geology and Geophysics, Ctr. for the Study of Global Change, Yale University, New Haven, CT 06520-8109, United States 1-2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-2642518967&doi=10.1016%2fj.palaeo.2004.02.028&partnerID=40&md5=03361b568aaa4b30b2996ca12cf22a7b cited By 56 L. Alegret E. Thomas article Prioul2004477 Within the Corinth Rift Laboratory, dipole sonic data have been acquired in the AIG 10 well between depths 711 and 1004 m during three passes of a sonic logging tool at three different borehole fluid pressures. Specific sections of the well reveal clear characteristics of either moderate-to-large azimuthal anisotropy (9-25%) below the Aigion Fault, e.g., 779-784 and 809-816 m, with a fast-shear azimuth directed 105°, or homogeneous isotropic medium (i.e., 735-753 m) between the casing shoe and the fault. The presence of the fault is coincident with the identification of lower velocities over an interval of approximately 12-14 m. Analysis of the data reveals that the formation is not acoustically stress-sensitive to the 3 MPa differential pressure applied. Interpretation of the sonic data with complementary image logs suggests the anisotropy is due to intrinsic fractures and bedding, and the fast-shear direction 105° is consistent with the regional maximum horizontal stress. © 2004 Académie des sciences. Published by Elsevier SAS. All rights reserved. Article 2004 French 16310713 10.1016/j.crte.2003.11.008 Comptes Rendus - Geoscience 336 477 – 485 4-5 Gulf of Corinth; Ionian Sea; Mediterranean Sea; acoustic logging; borehole geophysics; fault; structural geology https://www.scopus.com/inward/record.uri?eid=2-s2.0-1942537187&doi=10.1016%2fj.crte.2003.11.008&partnerID=40&md5=80f3ffb90eb1643857bbe9bf4ac5cd17 Cited by: 9 Romain Prioul Thomas Plona Michael Kane Bikash Sinha Peter Kaufman Claude Signer article Dawson2004193 The current study examines the potential cyclical nature of the elemental concentration record of silicon in sediment from Lake Baikal site BDP 96-2 in an attempt to clarify trends in periodicity observed for periods from 700 kyr BP to the present, 760 kyr BP to 1.43 Ma, and 1.47 to 2.4 Ma. The results indicate the presence of the 100 kyr cycle during the past 700 000 yr, as identified in other research. They also indicate the presence of a strong 74 kyr cycle from 760 kyr BP to 1.43 Md, with a weaker 44 kyr cycle. For the period from 1.47 to 2.4 Ma, we observed evidence of strong 465 and 155 kyr cycles, in addition to a moderate 93 kyr cycle and various lesser cycles. This new evidence represents one of the first findings of longer cycles, as predicted by classic insolation theory, and sheds some initial light on Imbrie's 400 kyr question. © Inter-Research 2004. Article 2004 English 0936577X 10.3354/cr026193 Climate Research 26 Inter-Research 193 – 197 3 Eurasia; Lake Baikal; Russian Federation; climate change; lacustrine deposit; Milankovitch cycle; orbital forcing; paleoenvironment; silicon https://www.scopus.com/inward/record.uri?eid=2-s2.0-4344598924&doi=10.3354%2fcr026193&partnerID=40&md5=7a55b7052696d3d7b5582270725a99cc Cited by: 3; All Open Access, Bronze Open Access R. Dawson R. Wei S. Tao Y. Ito K. Yamanaka H. Haraguchi article Avallone2004301 GPS (Global Positioning System) data collected in the Corinth Rift during eleven campaigns between 1990 and 2001 provide velocities of 57 points with ∼1.5 mm yr-1 accuracy. Peloponnesos moves at 30 mm yr-1 to the N215° E with respect to a fixed Europe. Extension across the rift is accommodated in a narrow band offshore. Its rate increases from east to west and is 16 mm yr-1 near Aigion. Both sides of the rift behave as clockwise rotating blocks with rates of 7±0.5° M yr-1 and 2.8±0.8° M yr-1, respectively for the northern and southern blocks. After removing block rotations, the northern block shows a north-south extension rate of 120±50 nstrain yr-1, whereas the southern block indicates the internal deformation is still inside the error bar (<20 nstrain yr-1). The strain accumulation across the major faults located along the southern coast of the Corinth Gulf is less than 1 mm yr-1. This implies long recurrence periods for large earthquakes on these faults. © 2004 Académie des sciences. Published by Elsevier SAS. All rights reserved. Article 2004 French 16310713 10.1016/j.crte.2003.12.007 Comptes Rendus - Geoscience 336 301 – 311 4-5 crustal deformation; GPS; rift zone; seismotectonics https://www.scopus.com/inward/record.uri?eid=2-s2.0-1942473593&doi=10.1016%2fj.crte.2003.12.007&partnerID=40&md5=52f3a83eabeacb5a953ee67c65ab09d6 Cited by: 144; All Open Access, Green Open Access Antonio Avallone Pierre Briole Amalia Maria Agatza-Balodimou Harilaos Billiris Olivier Charade Christiana Mitsakaki Alexandre Nercessian Kalliopi Papazissi Dimitris Paradissis George Veis article Chéry2004 Stress measurements made in the SAFOD pilot hole provide an opportunity to study the relation between crustal stress outside the fault zone and the stress state within it using an integrated mechanical model of a transform fault loaded in transpression. The results of this modeling indicate that only a fault model in which the effective friction is very low (<0.1) through the seismogenic thickness of the crust is capable of matching stress measurements made in both the far field and in the SAFOD pilot hole. The stress rotation measured with depth in the SAFOD pilot hole (∼28°) appears to be a typical feature of a weak fault embedded in a strong crust and a weak upper mantle with laterally variable heat flow, although our best model predicts less rotation (15°) than observed. Stress magnitudes predicted by our model within the fault zone indicate low shear stress on planes parallel to the fault but a very anomalous mean stress, approximately twice the lithostatic stress. Copyright 2004 by the American Geophysical Union. 2004 English 00948276 10.1029/2004GL019521 Geophysical Research Letters 31 L15S13 1-5 Lab. Dynamique de la Lithosphere, Université de Montpellier 2, Montpellier F-34095, France; Department of Geophysics, Stanford University, Stanford, CA 94305, United States; U.S. Geological Survey, 345 Middlefield Road, Menlo Park, CA 94025, United States 15 Friction; Geophysical prospecting; Mathematical models; Seismology; Shear stress; Stress analysis, Fault zones; Pilot holes; Stress measurements; Transpression, Boreholes, borehole geophysics; in situ stress; model; San Andreas Fault; stress measurement, California; North America; Parkfield; United States; Western Hemisphere; World https://www.scopus.com/inward/record.uri?eid=2-s2.0-7044237470&doi=10.1029%2f2004GL019521&partnerID=40&md5=e59f288a51dba9e0d734db61f03675cb cited By 53 J. Chéry M.D. Zoback S. Hickman article Peck200437 We report magnetic hysteresis results from sediment cores obtained from Lake Bosumtwi, Ghana. As a hydrologically closed basin, the water budget of Lake Bosumtwi is extremely sensitive to changes in the precipitation/ evapotranspiration balance. Lake Bosumtwi lies in the path of the seasonal migration of the intertropical convergence zone (ITCZ); hence, the lake is ideally situated to study monsoon variability in West Africa. Five distinctive magnetic mineral zones (A-E) were identified in the 11-m-long sediment cores that span the last 26,000 calendar years. Prior to 12 calendar (cal) ka, low concentrations of multidomain, high-coercivity magnetic minerals are present. Three prominent shifts towards very high concentrations of high-coercivity iron sulfide (greigite) magnetic minerals are centered at 12,470, 17,290, and 22,600 calendar years during the last glacial period (magnetic zones D1-3). Between 12 and 3.2 cal ka, there is an abrupt shift to moderately high concentrations of mixed multidomain and single-domain, low-coercivity minerals and an organic-rich sapropel lithology. Since 3.2 cal ka, the magnetic mineral parameters reveal a shift to increased amounts of high-coercivity magnetic minerals. These magnetic mineral zones document tropical climate variability on a variety of temporal scales. Glacial age sediments have a high-coercivity magnetic mineralogy due to increased aeolian dust transport from the Sahel to Lake Bosumtwi as well as postdepositional reductive diagenesis. During the last glacial period, the increased strength of Harmattan and North African continental trade winds, the southward depression of the ITCZ, and weakened summer monsoon strength resulted in increased regional aridity and greater dust flux out of Sahel source regions. The greigite-bearing D magnetic zones correspond to brief lowstands in the level of Lake Bosumtwi and likely represent periods of intensified aridity in West Africa. The D magnetic zones closely resemble the timing and duration of Heinrich events and suggest a hemispheric-scale climatic coupling between the tropics and poles. The well-documented African humid period (AHP) is characterized by abrupt shifts in magnetic parameters between 12 and 3.2 cal ka. Dust flux to Lake Bosumtwi is inferred to be very low during this humid interval due to the strengthening of the summer monsoon. Since 3.2 cal ka, the magnetic mineral parameters suggest increased aridity as compared to the AHP. This work demonstrates that the magnetic properties of Lake Bosumtwi sediment are a sensitive recorder of abrupt climate change of global significance. © 2004 Elsevier B.V. All rights reserved. Article 2004 English 00310182 10.1016/S0031-0182(04)00438-9 Palaeogeography, Palaeoclimatology, Palaeoecology 215 Elsevier B.V. 37 – 57 1-2 Africa; Ashanti; Eastern Hemisphere; Ghana; Lake Bosumtwi; Sub-Saharan Africa; West Africa; World; climate change; dust; greigite; magnetic mineral; monsoon; paleoclimate; paleolimnology; Quaternary; sedimentation; water budget https://www.scopus.com/inward/record.uri?eid=2-s2.0-8444234767&doi=10.1016%2fS0031-0182%2804%2900438-9&partnerID=40&md5=a909ad7ba355f1387c2b65115d316b3c Cited by: 95 John A. Peck Ryan R. Green Tim Shanahan John W. King Jonathan T. Overpeck Christopher A. Scholz article Xu2004560 Soil samples were collected from the upper layers of two Unzen volcano Scientific Drilling Project boreholes and dated by radiocarbon using accelerator mass spectrometry (AMS). The humic soils underlying volcanic related lahar flow deposits at a depth of 56.42 m of the USDP-1 borehole gave a 14C age of 18.8 kaBP, suggesting that the accumulation of the lahar flow deposits was caused by the Kureishibaru pyroclastic eruption (19 kaBP) dated at the surface. The humic soils underlying a pyroclastic flow deposit at depths of 71.60-71.90 m of the USDP-2 borehole gave 14C ages of 27.5 and 29.3 kaBP at the top and bottom layers, respectively. This reveals that the initial activity of Fugendake volcano occurred around 27 kaBP and the collapse of Myokendake volcano around 29 kaBP. © 2004 Elsevier B.V. All rights reserved. 2004 English 0168583X 10.1016/j.nimb.2004.04.104 Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms 223-224 560-567 JNC, Tono Geoscience Center, 959-31 Jorinji, Toki, Gifu 509-5102, Japan; Scottish Univ. Environ. Res. Centre, Scottish Enterprise Technology Park, East Kilbride G75 0QF, United Kingdom; Geological Survey of Japan, 1-1-3 Higashi, Tsukuba, Ibaraki 305-8567, Japan; IDEP, Tono Res. Inst. of Earthquake Sci., 1-47 Yamanouchi, Mizunami, Gifu 509-6132, Japan SPEC. ISS. Boreholes; Carbon; Deposits; Geochronology; Leveling (machinery); Mass spectrometry; Project management; Radioactive elements; Stratigraphy; Volcanoes, Accelerator mass spectrometry (AMS); Pyroclastic eruption; Soil carbon fraction; Unzen volcano, Soils https://www.scopus.com/inward/record.uri?eid=2-s2.0-3943106776&doi=10.1016%2fj.nimb.2004.04.104&partnerID=40&md5=0325a5f97dd37af1578d249fdea5e10b cited By 8 S. Xu H. Hoshizumi Y. Ochiai H. Aoki K. Uto article Imanishi2004 We estimate the source parameters of #3 microearthquakes by jointly analyzing seismograms recorded by the 32-level, 3-component seismic array installed in the SAFOD Pilot Hole. We applied an inversion procedure to estimate spectral parameters for the omega-square model (spectral level and corner frequency) and Q to displacement amplitude spectra. Because we expect spectral parameters and Q to vary slowly with depth in the well, we impose a smoothness constraint on those parameters as a function of depth using a linear first-differenfee operator. This method correctly resolves corner frequency and Q, which leads to a more accurate estimation of source parameters than can be obtained from single sensors. The stress drop of one example of the SAFOD target repeating earthquake falls in the range of typical tectonic earthquakes. Copyright 2004 by the American Geophysical Union. 2004 English 00948276 10.1029/2004GL019420 Geophysical Research Letters 31 L12S09 1-5 Geological Survey of Japan, Natl. Inst. Adv. Indust. Sci/Technol, 1-1 Higashi 1-Chrome, Tsukuba, Ibaraki 305-8567, Japan; U.S. Geological Survey, Menlo Park, CA 94025, United States; USGS Alaska Volcano Observatory, 4200 University Ave., Anchorage, AK 99508, United States 12 Frequencies; Function evaluation; Mathematical models; Mathematical operators; Parameter estimation; Seismology; Sensors; Tectonics; Frequency estimation; Geophysics; Seismology, Displacement amplitude spectra; Seismic arrays; Seisomograms, Earthquakes; Earthquakes, deep drilling; earthquake mechanism; San Andreas Fault; source parameters, Accurate estimation; Difference operators; Displacement amplitudes; Earthquake source parameters; Repeating earthquake; Smoothness constraints; Spectral parameters; Tectonic earthquakes https://www.scopus.com/inward/record.uri?eid=2-s2.0-6044242059&doi=10.1029%2f2004GL019420&partnerID=40&md5=e7668fbbbcb6503ab407bdfaa0c28211 cited By 53 K. Imanishi W.L. Ellsworth S.G. Prejean article Blythe2004 The San Andreas Fault Observatory at Depth (SAFOD) pilot hole traverses the upper 2 km of a site 1.8 km west of the San Andreas fault (SAF) near Parkfield, California. In order to evaluate the burial and exhumation history of the site and its relationship to the kinematics and mechanics of the SAF, we use 15 apatite fission-track (FT) and 5 (U-Th)/He analyses from pilot hole samples to document their thermal history. Sample ages decrease with depth: FT and (U-Th)/He ages range from ∼60 and ∼31 Ma, respectively, in the upper 800 m of the hole to ∼3 and 1 Ma at the base of the hole (2.2 km depth, 93°C). Thermal modeling of the distribution of FT lengths indicates three events in the last 80 Ma: 1) cooling and exhumation of >60°C that culminated at ∼30 Ma; 2) reheating of ∼50°C from ∼30 to 8-4 Ma, probably as the result of basin subsidence and burial by 1-1.5 km of sediments; and 3) cooling of ∼30°C and estimated Coast Range exhumation of ∼1 km since 8-4 Ma. Copyright 2004 by the American Geophysical Union. 2004 English 00948276 10.1029/2003GL019407 Geophysical Research Letters 31 L15S16 1-4 Department of Earth Sciences, University of Southern California, Los Angeles, CA 90089-0740, United States; Department of Earth/Planetary Sci., University of California, Berkeley, CA 94720-4767, United States 15 Cooling; Geophysical prospecting; Heating; Kinematics; Mathematical models; Sediments; Thermal effects; Thermoanalysis, Fission-track (FT); Pilot holes; San Andreas Fault (SAF); Thermochronometry, Boreholes, borehole geophysics; burial (geology); exhumation; fission track dating; San Andreas Fault; thermal evolution; thermochronology, California; North America; Parkfield; United States; Western Hemisphere; World https://www.scopus.com/inward/record.uri?eid=2-s2.0-7044246180&doi=10.1029%2f2003GL019407&partnerID=40&md5=9b67824577f645379d695170784ca903 cited By 15 A.E. Blythe M.A. d'Alessio R. Bürgmann article Unsworth2004 The magnetotelluric dataset collected on the San Andreas Fault at Parkfield has been re-analyzed using superior inversion algorithms that have been developed in recent years. A combination of constrained inversion, forward modeling and synthetic inversion studies are used, and show that at the SAFOD site, the low resistivity fault zone extends to a depth of 2-3 km. An extended zone of low resistivity cast of the San Andreas Fault may be connected to the SAF at seismogenic depths. The connection increases along the SAF to the northwest and may be related to the transition from locked to creeping seismic behavior. Copyright 2004 by the American Geophysical Union. 2004 English 00948276 10.1029/2003GL019405 Geophysical Research Letters 31 L12S05 1-4 Institute for Geophysical Research, Department of Physics, University of Alberta, Edmonton, Alta. T6G 2J1, Canada; GeoForschungsZentrum, Telegrafenberg, Potsdam D-14473, Germany 12 Algorithms; Data reduction; Geophysics; Magnetoelectric effects; Mathematical models; Seismology; Strike-slip faults, Datasets; Fault zone; Magnetotelluric exploration, Electric conductivity; Magnetotellurics, electrical resistivity; magnetotelluric method; San Andreas Fault, Constrained inversions; Electrical resistivity structures; Forward modeling; Inversion algorithm; Low resistivity; Magnetotelluric exploration; San Andreas fault; Seismic behavior https://www.scopus.com/inward/record.uri?eid=2-s2.0-6044272858&doi=10.1029%2f2003GL019405&partnerID=40&md5=cc4ecccb71b7ba7a6b5f4c25764c9e54 cited By 98 M. Unsworth P.A. Bedrosian article Wilhelm2004813 Within the frame of the International Continental Deep Drilling Program (ICDP) and as a part of the Chicxulub Scientific Drilling Project (CSDP), high resolution temperature measurements were performed in the borehole Yaxcopoil-1 (Yax-1). The temperature was logged to the depth of 858 m seven times between March 6-19, 2002, starting 10 days after the hole was shut in and mud circulation ceased. Successive logs revealed only small temperature variations in time and space, indicating a fast temperature recovery to almost undisturbed conditions prior to the first log. From these logs, a mean temperature gradient of ∼37 mK/m was determined below the uppermost 250 m. Another temperature log was recorded on May 24, 2003 (15 months after the shut in) to a depth of 895 m. The obtained temperature profile is very similar to the 2002 profile, with an insignificantly higher mean gradient below 250 m that may indicate a long-term return to the pre-drilling temperature. The temperature in the uppermost part of the hole bears signs of considerable influence of a convective contribution to the vertical thermal heat transfer. The depth extent of the convection seems to have deepened from 150 m in March 2002 to 230 m in May 2003. Based on the observed temperature gradient and the rock types encountered in the borehole above 670 m, the conducted heat flow is expected to be in the range 65-80 mW/m2. © Meteoritical Society, 2004. 2004 10.1111/j.1945-5100.2004.tb00931.x Meteoritics and Planetary Science 39 813-819 Geophysical Institute, University of Karlsruhe, Herzstrasse 16, Karlsruhe D-76187, Germany; Geophysical Institute, Czech Academy of Sciences, Prageu, Czech Republic; Institute of Applied Geosciences, Technical University of Berlin, Berlin, Germany; Moscow State Geol. Prospecting Univ., Moscow, Russian Federation 6 https://www.scopus.com/inward/record.uri?eid=2-s2.0-3943062854&doi=10.1111%2fj.1945-5100.2004.tb00931.x&partnerID=40&md5=45688331b1289b14ce7927ec434e905e cited By 20 H. Wilhelm P. Heidinger J. Šafanda V. Čermák H. Burkhardt Yu. Popov article Hickman2004 2004 English 00948276 10.1029/2004GL020688 Geophysical Research Letters 31 L12S01 1-4 U.S. Geological Survey, 345 Middlefield Road, Menlo Park, CA 94025, United States; Department of Geophysics, Stanford University, Stanford, CA 94305, United States 12 earthquake; San Andreas Fault; seismic hazard, California; North America; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-6044266089&doi=10.1029%2f2004GL020688&partnerID=40&md5=54c4d886fe8465f8ee1477152692dbe8 cited By 110 S. Hickman M. Zoback W. Ellsworth article Goto20041233 The possibility of ocean water invasion into the Chicxulub crater following the impact at the Cretaceous/Tertiary boundary was investigated based on examination of an impactite between approximately 794.63 and 894.94 m in the Yaxcopoil-1 (Yax-1) core. The presence of cross lamination in the uppermost part of the impactite suggests the influence òf an oçean current at least during the sedimentation of this interval. Abundant occurrence of nannofossils of late Campanian to early Maastrichtian age in the matrices of samples from the upper part of the impactite suggests that the carbonate sediments deposited on the inner rim margin and outside the crater were eroded and transported into the crater most likely by ocean water that invaded the crater after its formation. The maximum grain size of limestone lithics and vesicular melt fragments, and grain and bulk chemical compositions show a cyclic variation in the upper part of the impactite. The upward fining grain size and the absence of erosional contact at the base of each cycle suggest that the sediments were derived from resuspension of units elsewhere in the crater, most likely by high energy currents association with ocean water invasion. © Meteoritical Society, 2004. Printed in USA. 2004 10.1111/j.1945-5100.2004.tb01139.x Meteoritics and Planetary Science 39 1233-1247 Department of Earth/Planet Science, The University of Tokyo, 7-3-1 Hongo, Tokyo 113 0033, Japan; Department of Geosciences, Pennsylvania State University, University Park, PA 16802, United States; Department of Earth Sciences, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan; Department of Complexity Sci./Eng., The University of Tokyo, 7-3-1 Hongo, Tokyo 113-0033, Japan 7 https://www.scopus.com/inward/record.uri?eid=2-s2.0-3943065105&doi=10.1111%2fj.1945-5100.2004.tb01139.x&partnerID=40&md5=763cf7137cd4416d8e213bc91b7a49ed cited By 43 K. Goto R. Tada E. Tajika T.J. Bralower T. Hasegawa T. Matsui article Wohlgemuth2004791 Impact structures in the solar system are mainly recognized and explored through remote sensing and, on Earth, through geophysical deep sounding. To date, a continuous scientific sampling of large impact craters from cover rocks to target material has only seldom been performed. The first project to deep-drill and core into one of the largest and well-preserved terrestrial impact structures was executed in the winter of 2001/2002 in the 65 Myr-old Chicxulub crater in Mexico using integrated coring sampling and in situ measurements. The combined use of different techniques allows a three-dimensional insight and a better understanding of impact processes. Here, we report the integration of conventional rotary drilling techniques with wireline mining coring technology that was applied to drill the 1510 m-deep Yaxcopoil-1 (Yax-1) well about 40 km southwest of Mérida, Yucatán, Mexico. During the course of the project, we recovered approximately 900 m of intact core samples including the transitions of reworked ejecta to post-impact sediments, and that one from large blocks of tilted target material to impact-generated rocks, i.e., impact melt breccias and suevites. Coring was complemented by wireline geophysical measurements to obtain a continuous set of in situ petrophysical data of the borehole walls. The data acquired is comprised of contents of a natural radioactive element, velocities of compressional sonic waves, and electrical resistivity values. All the digital data sets, including technical drilling parameters, initial scientific sample descriptions, and 360° core pictures, were distributed during the course of the operations via Internet and were stored in the ICDP Drilling Information System (http://www.icdp-online.org), serving the global community of cooperating scientists as a basic information service. © Meteoritical Society, 2004. 2004 10.1111/j.1945-5100.2004.tb00929.x Meteoritics and Planetary Science 39 791-797 Operational Support Group ICDP, GeoForschungsZentrum Potsdam, Telegrafenberg A34, Potsdam D-14473, Germany 6 https://www.scopus.com/inward/record.uri?eid=2-s2.0-4043149925&doi=10.1111%2fj.1945-5100.2004.tb00929.x&partnerID=40&md5=a45511189cd3cf2f79a5a6da2e4f862e cited By 14 L. Wohlgemuth E. Bintakies R. Conze U. Harms article Dressler2004857 The impact breccias encountered in drill hole Yaxcopoil-1 (Yax-1) in the Chicxulub impact structure have been subdivided into six units. The two uppermost units are redeposited suevite and suevite, and together are only 28 m thick. The two units below are interpreted as a ground surge deposit similar to a pyroclastic flow in a volcanic regime with a fine-grained top (unit 3; 23 m thick; nuée ardente) and a coarse breccia (unit 4;∼15 m thick) below. As such, they consist of a mélange of clastic matrix breccia and melt breccia. The pyroclastic ground surge deposit and the two units 5 and 6 below are related to the ejecta curtain. Unit 5 (∼24 m thick) is a silicate impact melt breccia, whereas unit 6 (10 m thick) is largely a carbonate melt breccia with some clastic-matrix components. Unit 5 and 6 reflect an overturning of the target stratigraphy. The suevites of units 1 and 2 were deposited after emplacement of the ejecta curtain debris. Reaction of the super-heated breccias with seawater led to explosive activity similar to phreomagmatic steam explosion in volcanic regimes. This activity caused further brecciation of melt and melt fragments. The fallback suevite deposit of units 1 and 2 is much thinner than suevite deposits at larger distances from the center of the impact structure than the 60 km of the Yax-1 drill site. This is evidence that the fallback suevite deposit (units 1 and 2) originally was much thicker. Unit 1 exhibits sedimentological features suggestive of suevite redeposition. Erosion possibly has occurred right after the K/T impact due to seawater backsurge, but erosion processes spanning thousands of years may also have been active. Therefore, the top of the 100 m thick impactite sequence at Yaxcopoil, in our opinion, is not the K/T boundary. © Meteoritical Society, 2004. 2004 10.1111/j.1945-5100.2004.tb00935.x Meteoritics and Planetary Science 39 857-878 Lunar and Planetary Institute, 3600 Bay Area Boulevard, Houston, TX 77058, United States; Geophysical Institute, University of Alaska, Fairbanks, AK 99709, United States; Lockheed Martin, 2400 Nasa Road 1, Houston, TX 77058, United States; Geological Survey of Canada, Ottawa, K1A 0E8, Canada 6 https://www.scopus.com/inward/record.uri?eid=2-s2.0-3943082685&doi=10.1111%2fj.1945-5100.2004.tb00935.x&partnerID=40&md5=bcf1d54731e8f67af3b4c4a2bf195e87 cited By 51 B.O. Dressler V.L. Sharpton C.S. Schwandt D. Ames article Wittman2004931 Petrographic descriptions of three dike breccia lithologies from drill core Yaxcopoil-1 (Yax-1) are presented. They occur within allochthonous units of displaced sedimentary megablocks of the Chicxulub impact structure. The suevitic dike breccias are the uppermost dike lithology. They contain melt rock particles and melt injections into the dike groundmass. Shock features occur ubiquitously and indicate a strong thermal annealing. Flow textures suggest a highly energetic emplacement process, possibly during the excavation stage as a ground-surge related deposit. The impact melt rock dikes are present in a strongly brecciated megablock interval as flow textured, anastomozing veinlets of impact melt rock that were altered to clay minerals. The melt impregnated a dolomitic host rock, indicating a low viscosity and, thus, high initial temperatures. Brecciation of the impact melt rock dikes occurred while they were still below the glass transition temperature, suggesting that dynamic conditions prevailed shortly after the emplacement process. Major element data indicates that the impact melt rock dikes differ in composition from the homogenized impact melt rock of Chicxulub. This could point to an emplacement during the late compression or early excavation stages of cratering. The clastic polymict dike breccias are coeval with pervasive brittle fracturing of the host rocks. They bear clasts including some crystalline basement and possible melt rock particles in a fine-grained dolomite matrix with turbulent flow textures. Fabric and texture indicate a granular flow at ambient pressures. Such conditions could be envisaged for the excavation phase while the transient cavity grew and fractures opened. © Meteoritical Society, 2004. 2004 10.1111/j.1945-5100.2004.tb00938.x Meteoritics and Planetary Science 39 931-954 Institut für Mineralogie, Museum für Naturkunde, Humboldt Universität Berlin, Invalidenstrasse 43, Berlin 10115, Germany 6 https://www.scopus.com/inward/record.uri?eid=2-s2.0-3943104872&doi=10.1111%2fj.1945-5100.2004.tb00938.x&partnerID=40&md5=28665c60f2cf39155d523979d89ace62 cited By 35 A. Wittman T. Kenkmann R.T. Schmitt L. Hecht D. Stöffler article Kring2004879 The Chicxulub Scientific Drilling Project (CSDP), Mexico, produced a continuous core of material from depths of 404 to 1511 m in the Yaxcopoil-1 (Yax-1) borehole, revealing (top to bottom) Tertiary marine sediments, polymict breccias, an impact melt unit, and one or more blocks of Cretaceous target sediments that are crosscut with impact-generated dikes, in a region that lies betweeon the peak ring and final crater rim. The impact melt and breccias in the Yax-1 borehole are 100 m thick, which is approximately 1/5 the thickness of breccias and melts exposed in the Yucatán-6 exploration hole, which is also thought to be located between the peak ring and final rim of the Chicxulub crater. The sequence and composition of impact melts and breccias are grossly similar to those in the Yucatán-6 hole. Compared to breccias in other impact craters, the Chicxulub breccias are incredibly rich in silicate melt fragments (up to 84% versus 30 to 50%, for example, in the Rieś). The melt in the Yax-1 hole was produced largely from the silicate basement lithologies that lie beneath a 3 km- thick carbonate platform in the target area. Small amounts of immiscible molten carbonate were ejected with the silicate melt, and clastic carbonate often forms the matrix of the polymict breccias. The melt unit appears to have been deposited while molten but brecciated after solidification. The melt fragments in the polymict breccias appear to have solidified in flight, before deposition, and fractured during transport and deposition. © Meteoritical Society, 2004. 2004 10.1111/j.1945-5100.2004.tb00936.x Meteoritics and Planetary Science 39 879-897 Lunar and Planetary Laboratory, University of Arizona, 1629 East University Boulevard, Tucson, AZ 85721, United States; Planetary Sciences Branch, SN2, NASA Johnson Space Center, Houston, TX 77058, United States; Instituto de Geofisica, Univ. Nacl. Autonoma de Mexico, Mexico City 04510, Mexico 6 https://www.scopus.com/inward/record.uri?eid=2-s2.0-3943080586&doi=10.1111%2fj.1945-5100.2004.tb00936.x&partnerID=40&md5=e72bfdaaa7e9274ed5390ecc227166b9 cited By 62 D.A. Kring F. Horz L. Zurcher J. Urrutia Fucugauchi report 2004 10.3133/ofr20041016 2004-1016 http://pubs.er.usgs.gov/publication/ofr20041016 Lucy E. Edwards W.J.J. Wright Horton Jr. Gregory S. Gohn article Léonardi2004385 Two wells have been equipped in 2002, in order to provide complementary hydrological information within the framework of the European project devoted to the Corinth Rift Laboratory. In this distensive tectonic domain, temporal series of flow (Neratzes well) and of piezometric fluid level (Trapeza well) have been recorded in 2002. We present here a first analysis of the data. As far as Trapeza is concerned, we present the first results of the calibration of the well, using the tidal and barometric analyses. The strain sensitivity of the well, as well as the aquifer hydraulic conductivity, is derived from tides, whereas the specific storativity of the aquifer and its confinement degree are estimated from the barometric response. These preliminary results show that the aquifer has got properties that make possible the observation of coupled tectonic/hydrological processes. In addition, the time series let appear some fast and permanent variations of level. We analyse these phenomena and detail the various assumptions, which could explain these processes. As far as Neratzes is concerned, we present the first data measured from the flowmeter. Contrary to the piezometric data, the flow measurements are not conventional. At the end of this first year of measurement, we prove that we are able to record the tides effect using the flowmeter. A prospective analysis of all these results will be drawn. © 2004 Académie des sciences. Published by Elsevier SAS. All rights reserved. Article 2004 French 16310713 10.1016/j.crte.2003.11.018 Comptes Rendus - Geoscience 336 385 – 393 4-5 Gulf of Corinth; Ionian Sea; Mediterranean Sea; aquifer characterization; flow measurement; hydrological regime; rift zone; seismotectonics; tide https://www.scopus.com/inward/record.uri?eid=2-s2.0-1942473550&doi=10.1016%2fj.crte.2003.11.018&partnerID=40&md5=94580b62d2c9b5200c2c5fca7c8934db Cited by: 5 Véronique Léonardi Pierre Gavrilenko article Langbein2004 A network of 13 continuous GPS stations near Parkfield, California has been converted from 30 second to 1 second sampling with positions of the stations estimated in real-time relative to a master station. Most stations are near the trace of the San Andreas fault, which exhibits creep. The noise spectra of the instantaneous 1 Hz positions show flicker noise at high frequencies and change to frequency independence at low frequencies; the change in character occurs between 6 to 8 hours. Our analysis indicates that 1-second sampled GPS can estimate horizontal displacements of order 6 mm at the 99% confidence level from a few seconds to a few hours. High frequency GPS can augment existing measurements in capturing large creep events and postseismic slip that would exceed the range of existing creepmeters, and can detect large seismic displacements. Copyright 2004 by the American Geophysical Union. 2004 English 00948276 10.1029/2003GL019408 Geophysical Research Letters 31 L15S20 1-4 U.S. Geological Survey, 345 Middlefield Road, Menlo Park, CA 94025, United States; Cecil Ida Gn Inst Geophys/Plnt Phys, Scripps Institution of Oceanography, University of California, 9500 Gilman Drive, La Jolla, CA 92093-0225, United States 15 Acoustic noise; Atmospheric spectra; Global positioning system; Natural frequencies; Neural networks, Master station; Real time relative; San andreas fault, Real time systems, borehole geophysics; fault slip; GPS; monitoring system; San Andreas Fault; seismicity, California; North America; Parkfield; United States; Western Hemisphere; World https://www.scopus.com/inward/record.uri?eid=2-s2.0-7244234479&doi=10.1029%2f2003GL019408&partnerID=40&md5=e1316025edce2192fa2010d2a9add2f2 cited By 105 J. Langbein Y. Bock article Zürcher20041199 Petrographic, electron microprobe, and Raman spectrometric analyses of Yaxcopoil-1 core samples from the Chicxulub crater indicate that the impact generated a hydrothermal system. Relative textural and vein crosscutting relations and systematic distribution of alteration products reveal a progression of the hydrothermal event in space and time and provide constraints on the nature of the fluids. The earliest calcite, halite, and gaylussite suggest that the impactite sequence was initially permeated by a low temperature saline brine. Subsequent development of a higher temperature hydrothermal regime is indicated by thermal metamorphic diopside-hedenbergite (Aeg3Fs18-33En32-11Wo47-53) after primary augite and widespread Na-K for Ca metasomatic alkali exchange in plagioclase. Hydrothermal sphene, apatite, magnetite ± (bornite), as well as early calcite (combined 3 to 8 vol%) were introduced with metasomatic feldspar. A lower temperature regime characterized by smectite after probable primary glass, secondary chlorite, and other pre-existing mafic minerals, as well as very abundant calcite veins and open-space fillings, extensively overprinted the early hydrothermal stage. The composition of early and late hydrothermal minerals show that the solution was chlorine-rich (Cl/F&gt;10) and that its Fe/Mg ratio and oxidation state increased substantially (4 to 5 logfO2 units) as temperature decreased through time. The most altered zone in the impactite sequence occurs 30 m above the impact melt. The lack of mineralogical zoning about the impact melt and convective modeling constraints suggest that this unit was too thin at Yaxcopoil-1 to provide the necessary heat to drive fluids and implies that the hydrothermal system resulted from the combined effects of a pre-existing saline brine and heat that traveled to the Yaxcopoil-1 site from adjacent areas where the melt sheet was thicker. Limonite after iron oxides is more common toward the top of the sequence and suggests that the impactite section was subjected to weathering before deposition of the Tertiarý marine cover. In addition, scarce latest anatase stringers, chalcopyrite, and barite in vugs, francolite after apatite, and recrystallized halite are the likely products of limited post-hydrothermal ambient-temperature diagenesis, or ocean and/or meteoric water circulation. © Meteoritical Society, 2004. Printed in USA. 2004 10.1111/j.1945-5100.2004.tb01137.x Meteoritics and Planetary Science 39 1199-1221 Lunar and Planetary Laboratory, University of Arizona, 1629 East University Boulevard, Tucson, AZ 85721, United States 7 https://www.scopus.com/inward/record.uri?eid=2-s2.0-3943110342&doi=10.1111%2fj.1945-5100.2004.tb01137.x&partnerID=40&md5=4509b0924dfbe3b773e4f09a9ba1f31c cited By 72 L. Zurcher D.A. Kring article Tuchscherer2004899 The ICDP Yaxcopoil-1 (Yax-1) borehole located 60 km south-southwest of the center of the Chicxulub impact structure intercepted an interval of allogenic impactites (depth of 795-895 m). Petrographic analysis of these impactites allows them to be differentiated into five units based on their textural and modal variations. Unit 1 (795-922 m) comprises an apparently reworked, poorly sorted and graded, fine-grained, clast-supported, melt fragment-bearing suevitic breccia. The interstitial material, similar to units 2 and 3, is permeated by numerous carbonate veinlets. Units 2 (823-846 m) and 3 (846-861 m) are groundmass-supported breccias that comprise green to variegated angular and fluidal melt particles. The groundmass of units 2 and 3 comprises predominantly fine-grained calcite, altered alkali element-, Ca-, and Si-rich cement, as well as occasional lithic fragments. Unit 4 (861-885 m) represents a massive, variably devitrified, and brecciated impact melt rock. The lowermost unit, unit 5 (885-895 m), comprises highly variable proportions of melt rock particles (MRP) and lithic fragments in a fine-grained, carbonate-dominated groundmass. This groundmass could represent either a secondary hydrothermal phase or a carbonate melt phase, or both. Units 1 and 5 contain well-preserved foraminifera fossils and a significantly higher proportion of carbonate clasts than the other units. All units show diagnostic shock deformation features in quartz and feldspar clasts. Our observations reveal that most felsic and all mafic MRP are altered. They register extensive K-metasomatism. In terms of emplacement, we suggest that units 1 to 3 represent fallout suevite from a collapsing impact plume, whereby unit 1 was subsequently reworked by resurging water. Unit 4 represents a coherent impact melt body, the formation of which involved a significant proportion of crystalline basement. Unit 5 is believed to represent an initial ejecta/ground-surge deposit. © Meteoritical Society, 2004. 2004 10.1111/j.1945-5100.2004.tb00937.x Meteoritics and Planetary Science 39 899-930 Impact Cratering Research Group, School of Geosciences, University of the Witwatersrand, Private Bag 3, Johannesburg 2050, South Africa; Department of Geological Sciences, University of Vienna, Althanstrasse 14, Vienna A-1090, Austria; Council for Geosciences, Private Bag X112, Pretoria 0001, South Africa 6 https://www.scopus.com/inward/record.uri?eid=2-s2.0-3943099912&doi=10.1111%2fj.1945-5100.2004.tb00937.x&partnerID=40&md5=7647a561dbe59a29c7c5c27258ca9c70 cited By 33 M.G. Tuchscherer W.U. Reimold C. Koeberl R.L. Gibson D. Bruin article Schmitt2004979 The chemical composition of suevites, displaced Cretaceous target rocks, and impact-generated dikes within these rocks from the Yaxcopoil-1 (Yax-1) drill core, Chicxulub impact crater, Mexico, is reported and compared with the data from the Yucatán 6 (Y6) samples. Within the six suevite subunits of Yax-1, four units with different chemical compositions can be distinguished: a) upper/lower sorted and upper suevite (depth of 795-846 m); b) middle suevite (depth of 846-861 m); c) brecciated impact melt rock (depth of 861-88-5 m); and d) lower suevite (depth of 885-895 m). The suevite sequence (a), (b), and (d) display an increase of the CaO content and a decrease of the silicate basement component from top to bottom. In contrast, the suevite of Y6 shows an inverse trend. The different distances of the Yax-1 and Y6 drilling sites from the crater center (∼60, and ∼47 km, respectively) lead to different suevite sequences. Within the Cretaceous rocks of Yax-1, a suevitic dike (depth of ∼916 m) does not display chemical differences when compared with the suevite, while an impact melt rock dike (depth of ∼1348 m) is significantly enriched in immobile elements. A elastic breccia dike (depth of ∼1316 m) is dominated by material derived locally from the host rock, while the silicate-rich component is similar to that found in the suevite. Significant enrichments of the K2O content were observed in the Yax- 1 suevite and the impact-generated dikes. All impactites of Yax-1 and Y6 are mixtures of a crystalline basement and a carbonate component from the sedimentary cover. An anhydrite component in the impactites is missing (Yax-1) or negligible (Y6). 2004 10.1111/j.1945-5100.2004.tb00940.x Meteoritics and Planetary Science 39 979-1001 Institute of Mineralogy, Museum of Natural History, Humboldt-University of Berlin, Invalidenstrasse 43, Berlin D-10115, Germany 6 https://www.scopus.com/inward/record.uri?eid=2-s2.0-3943111548&doi=10.1111%2fj.1945-5100.2004.tb00940.x&partnerID=40&md5=47357405e9b86e5f254d960ab68c30d2 cited By 37 R.T. Schmitt A. Wittmann D. Stöffler article Glass20043971 We have determined the major and trace element compositions of 176 individual microtektites/spherules from the Australasian, Ivory Coast, and North American microtektite and clinopyroxene-bearing (cpx) spherule layers. Trace element contents for up to 30 trace elements were determined by instrumental neutron activation analysis (INAA), and major element compositions were determined using energy dispersive X-ray (EDX) analysis in combination with a scanning electron microscope (SEM). In addition, petrographic data were obtained for the cpx spherules using the SEM and EDX. This is the first trace element study of individual Australasian microtektites, and the data revealed the presence of a previously unrecognized group of Australasian microtektites with high contents of Ni (up to 471 ppm). In previous studies the high-Mg (HMg) Australasian microtektites were thought to be related to the HMg Australasian tektites, but our trace element data suggest that the high-Ni (HNi) Australasian microtektites, rather than the high-Mg microtektites, are related to the high-Mg Australasian tektites. We find that Cenozoic microtektites/spherules from a given layer can be distinguished from microtektites/spherules from other layers as a group, but it is not always possible to determine which layer an individual microtektite/spherule came from based only on trace element compositions. The cpx spherules and most of the microtektites have Cr, Co, and Ni contents that are higher than the average contents of these elements in the upper continental crust, suggesting the presence of a meteoritic component. The highest Cr, Co, and Ni contents are found in the cpx spherules (and low-Si cpx-related microtektites). Unetched to slightly etched cpx spherules have Ni/Cr and Ni/Co ratios that generally lie along mixing curves between the average upper continental crust and chondrites. The best fit appears to be with an LL chondrite. The moderately to heavily etched cpx spherules have values that lie off the mixing curves in a direction that suggests Ni loss, probably as a result of solution of a Ni-rich phase (olivine?). The Ni-rich Australasian microtektites also have Ni values that lie close to mixing curves between the average upper continental crust and chondrites. However, both the cpx spherules and HNi Australasian microtektites appear to have Ir (and to a lesser extent Au) contents that are much too low to have Ni/Ir ratios similar to chondritic values. We have no explanation for the low-Ir and -Au contents except to speculate that they may be the result of a complex fractionation process. The Ivory Coast and North American microtektites do not have high enough siderophile element contents to reach any firm conclusions regarding the presence of, or nature of, a meteoritic component in them. Trace element compositions are consistent with derivation of the Cenozoic microtektite/spherule layers from upper continental crust. The normal Australasian microtektites appear to have been derived from a graywacke or lithic arenite with a range in clay and quartz content. The source rock for the high-Mg Australasian microtektites is not known, but the HMg microtektites do not appear to be normal Australasian microtektites that were simply contaminated by meteorites or ultramafic rocks. The average Ivory Coast microtektite composition can be matched with a mixture of target rocks at the Bosumtwi crater. The average composition of the North American microtektites suggests an arkosic source rock, but with graywacke and quartz-rich end members. However, we could not match the composition of the North American microtektites with lithologies in impact breccias recovered from the Chesapeake Bay impact structure that is believed to be the source crater. Likewise, we could not match the composition of the cpx spherules with mixtures of basement rocks and overlying sedimentary deposits (for which compositional data are available) at the Popigai impact crater that may be the source crater for the cpx spherules. This may be because the cpx spherules were derived, in large part, from clastic surface rocks (sandstones and shales) for which no compositional data are available. Copyright © 2004 Elsevier Ltd. Article 2004 English 00167037 10.1016/j.gca.2004.02.026 Geochimica et Cosmochimica Acta 68 3971 – 4006 19 Cenozoic; clinopyroxene; geochemistry; spherule; tektite https://www.scopus.com/inward/record.uri?eid=2-s2.0-9144271217&doi=10.1016%2fj.gca.2004.02.026&partnerID=40&md5=d3172b3624d7f936143b793133aa6054 Cited by: 63 Billy P. Glass Heinz Huber Christian Koeberl article Carcione200473 We estimate the concentration of gas hydrate at the Mallik 2L-38 research site using P- and S-wave velocities obtained from well logging and vertical seismic profiles (VSP). The theoretical velocities are obtained from a generalization of Gassmann's modulus to three phases (rock frame, gas hydrate and fluid). The dry-rock moduli are estimated from the log profiles, in sections where the rock is assumed to be fully saturated with water. We obtain hydrate concentrations up to 75%, average values of 37% and 21% from the VSP P- and S-wave velocities, respectively, and 60% and 57% from the sonic-log P- and S-wave velocities, respectively. The above averages are similar to estimations obtained from hydrate dissociation modeling and Archie methods. The estimations based on the P-wave velocities are more reliable than those based on the S-wave velocities. © 2004 Elsevier B.V. All rights reserved. 2004 English 09269851 10.1016/j.jappgeo.2004.04.001 Journal of Applied Geophysics 56 73-78 Ist Naz di Oceanogr/di Geofis Sperim, Sgonico, Trieste 34010, Italy 1 Computer simulation; Phosphorus; Rocks; Seismology; Sulfur; Well logging, Dry-rocks; Wave velocities, Gas hydrates, gas hydrate; seismic velocity; seismic wave; vertical seismic profile; well logging, Canada; Mackenzie Delta; North America; Northwest Territories https://www.scopus.com/inward/record.uri?eid=2-s2.0-2942515936&doi=10.1016%2fj.jappgeo.2004.04.001&partnerID=40&md5=078d1c3c547215d4795c8a3a09126ba5 cited By 58 J.M. Carcione D. Gei article https://doi.org/10.1111/j.1945-5100.2004.tb01131.x Abstract The Yaxcopoil-1 (Yax-1) drill hole comprises Cretaceous limestones and calcarenites, the K/P boundary cocktail unit (including impact breccia), and a Danian marly clay layer overlain by calcareous marls. The biostratigraphy, paleobathymetry, and environmental turnover across the K/P interval were inferred after analyzing the planktic and benthic foraminiferal assemblages. The Cretaceous samples only contain a few poorly preserved planktic foraminifera of a middle Campanian to Maastrichtian age, while low-diversity benthic foraminiferal assemblages suggest a sufficient nutrient supply to the sea floor and a shallow neritic, occasionally stressed environment. The impact breccia and the redeposited suevite are overlain by a 46 cm-thick dolomitic calcareous sandstone unit that contains scarce, reworked planktic foraminiferal specimens. This unit probably represents the uppermost part of the initial infill of the crater. The uppermost centimeters of this unit are bioturbated, and its top represents a hiatus that spans at least the G. cretacea, Pv. eugubina, and part of the P. pseudobulloides biozones. This unit is overlain by a 3–4 cm-thick marly clay layer that represents a condensed layer. Benthic foraminiferal assemblages suggest a low food supply to the sea floor and environmental instability during the deposition of the marly clay layer. The increase in diversity of the assemblages indicates that the environmental conditions improved and stabilized from the G. compressa biozone toward the A. uncinata (P2) biozone. The Danian planktic and benthic foraminiferal assemblages indicate a deeper, probably bathyal environment. 2004 https://doi.org/10.1111/j.1945-5100.2004.tb01131.x Meteoritics & Planetary Science 39 1099-1111 7 https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1945-5100.2004.tb01131.x José A. ARZ Laia ALEGRET Ignacio ARENILLAS article Lüders20041187 Fluid inclusions studies in quartz and calcite in samples from the ICDP-Chicxulub drill core Yaxcopoil-1 (Yax-1) have revealed compelling evidence for impact-induced hydrothermal alteration. Fluid circulation through the melt breccia and the underlying sedimentary rocks was not homogeneous in time and space. The formation of euhedral quartz crystals in vugs hosted by Cretaceous limestones is related to the migration of hot (>200 °C), highly saline, metal-rich, hydrocarbon-bearing brines. Hydrocarbons present in some inclusions in quàrtz are assumed to derive from cracking of pre-impact organic matter. The center of the crater is assumed to be the source of the hot quartz-forming brines. Fluid inclusions in abundant newly-formed calcite indicate lower cyrstallization temperatures (75-100 °C). Calcite crystallization is likely related to a later stage of hydrothermal alteration. Calcite precipitated from saline fluids, most probably from formation water. Carbon and oxygen isotope compositions and REE distributions in calcites and carbonate host rocks suggest that the calcite-forming fluids have achieved close equilibrium conditions with the Cretaceous limestones. The precipitation of calcite may be related to the convection of local pore fluids, possibly triggered by impact-induced conductive heating of the sediments. © Meteoritical Society, 2004. Printed in USA. 2004 10.1111/j.1945-5100.2004.tb01136.x Meteoritics and Planetary Science 39 1187-1197 GeoForschungsZentrum Potsdam, Telegrafenberg, Potsdam D-14473, Germany; Hamburger Synchrotronstrahlungslabor, Deutsches Elektronen-Synchrotron, Notkestrasse 85, Hamburg D-22603, Germany 7 https://www.scopus.com/inward/record.uri?eid=2-s2.0-3943098783&doi=10.1111%2fj.1945-5100.2004.tb01136.x&partnerID=40&md5=520fdc27870cc4fa13b859b134d7e38f cited By 33 V. Lüders K. Rickers article Lyon-Caen2004343 The 12 stations Corinth Rift Laboratory Seismological Network (CRLNET) aims at monitoring the seismicity (Ml>1) in the CRL area and at constraining the geometry of active structures at depth. Two years of microseismicity (2000-2001) recorded by the CRLNET in the Aigion area shows: (1) background seismicity inside the Corinth rift at depth of 4.5-11 km, deepening towards the north and no activity in the upper 4 km of the crust - this seismicity is not clearly related to major faults observed at the surface -; (2) a swarm, 6 km south of the city of Aigion, associated with the Mw=4.2, 8 April 2001 earthquake. This earthquake occurred at 6 km depth, on a SW-NE oriented fault dipping 40° to the northwest and corresponds to normal faulting with a right lateral component of slip. It likely occurred on an old structure reactivated in the present stress field. © 2003 Académie des sciences. Published by Elsevier SAS. All rights reserved. Article 2004 English 16310713 10.1016/j.crte.2003.12.004 Comptes Rendus - Geoscience 336 Elsevier Masson SAS 343 – 351 4-5 Gulf of Corinth; Ionian Sea; Mediterranean Sea; earthquake; fault slip; reactivation; rift zone; seismotectonics https://www.scopus.com/inward/record.uri?eid=2-s2.0-1942441394&doi=10.1016%2fj.crte.2003.12.004&partnerID=40&md5=f445abbe2476246a0805bc1f18cf722d Cited by: 70; All Open Access, Green Open Access Hélène Lyon-Caen Panayotis Papadimitriou Anne Deschamps Pascal Bernard Kostas Makropoulos Francesco Pacchiani Geneviève Patau article Stolper2004 The Hawaii Scientific Drilling Project recovered-3 km of basalt by coring into the flank of Mauna Kea volcano at Hilo, Hawaii. Rocks recovered from deeper than-1 km were deposited below sea level and contain considerable fresh glass. We report electron microprobe analyses of 531 glasses from the submarine section of the core, providing a high-resolution record of petrogenesis over ca. 200 Kyr of shield building of a Hawaiian volcano. Nearly all the submarine glasses are tholeiitic. SiO2 contents span a significant range but are bimodally distributed, leading to the identification of low-SiO2 and high-SiO2 magma series that encompass most samples. The two groups are also generally distinguishable using other major and minor elements and certain isotopic and incompatible trace element ratios. On the basis of distributions of high-and low-SiO2 glasses, the submarine section of the core is divided into four zones. In zone 1 (1079-1950 mbsl), most samples are degassed high-SiO2 hyaloclastites and massive lavas, but there are narrow intervals of low-SiO2 hyaloclastites. Zone 2 (-1950-2233 mbsl), a zone of degassed pillows and hyaloclastites, displays a continuous decrease in silica content from bottom to top. In zone 3 (2233-2481 mbsl), nearly all samples are undegassed low-SiO2 pillows. In zone 4 (2481-3098 mbsl), samples are mostly high-SiO2 undegassed pillows and degassed hyaloclastites. This zone also contains most of the intrusive units in the core, all of which are undegassed and most of which are low-SiO 2. Phase equilibrium data suggest that parental magmas of the low-SiO2 suite could be produced by partial melting of fertile peridotite at 30-40 kbar. Although the high-SiO2 parents could have equilibrated with harzburgite at 15-20 kbar, they could have been produced neither simply by higher degrees of melting of the sources of the low-SiO 2 parents nor by mixing of known dacitic melts of pyroxenite/eclogite with the low-SiO2 parents. Our hypothesis for the relationship between these magma types is that as the low-SiO2 magmas ascended from their sources, they interacted chemically and thermally with overlying peridotites, resulting in dissolution of orthopyroxene and clinopyroxene and precipitation of olivine, thereby generating high-SiO2 magmas. There are glasses with CaO, Al2O3, and SiO2 contents slightly elevated relative to most low-SiO2 samples; we suggest that these differences reflect involvement of pyroxene-rich lithologies in the petrogenesis of the CaO-Al2O3-enriched glasses. There is also a small group of low-SiO2 glasses distinguished by elevated K2O and CaO contents; the sources of these samples may have been enriched in slab-derived fluid/melts. Low-SiO2 glasses from the top of zone 3 (2233-2280 mbsl) are more alkaline, more fractionated, and incompatible-element-enriched relative to other glasses from zone 3. This excursion at the top of zone 3, which is abruptly overlain by more silica-rich tholeiitic magmas, is reminiscent of the end of Mauna Kea shield building higher in the core. Copyright 2004 by the American Geophysical Union. Article 2004 English 15252027 10.1029/2003GC000553 Geochemistry, Geophysics, Geosystems 5 Division of Geological and Planetary Sciences, California Institute of Technology, MS 170-25, Pasadena, CA 91125, United States; Department of Geology and Geophysics, University OfHawaii at Manoa, 2525 Correa Road, Honolulu, HI 96822, United States 7 https://www.scopus.com/inward/record.uri?eid=2-s2.0-22444435099&doi=10.1029%2f2003GC000553&partnerID=40&md5=09ce93961c70f63ad62b6e3c95adba1b cited By 94 E. Stolper S. Sherman M. Garcia M. Baker C. Seaman article Thurber2004 We present results from the tomographic analysis of seismic data from the Parkfield area using three different inversion codes. The models provide a consistent view of the complex velocity structure in the vicinity of the San Andreas, including a sharp velocity contrast across the fault. We use the inversion results to assess our confidence in the absolute location accuracy of a potential target earthquake. We derive two types of accuracy estimates, one based on a consideration of the location differences from the three inversion methods, and the other based on the absolute location accuracy of "virtual earthquakes." Location differences are on the order of 100-200 m horizontally and up to 500 m vertically. Bounds on the absolute location errors based on the "virtual earthquake" relocations are ∼ 50 m horizontally and vertically. The average of our locations places the target event epicenter within about 100 m of the SAF surface trace. Copyright 2004 by the American Geophysical Union. 2004 English 00948276 10.1029/2004GL019398 Geophysical Research Letters 31 L12S02 1-4 Department of Geology and Geophysics, University of Wisconsin-Madison, 1215 W. Dayton St., Madison, WI 53706, United States; Department of Earth/Environ. Sci., Rensselaer Polytechnic Institute, Troy, NY 12180, United States; U.S. Geological Survey, 345 Middefield Rd., Menlo Park, CA 94035, United States 12 Data acquisition; Error analysis; Geophysics; Mathematical models; Seismology; Tomography; Velocity measurement; Earthquakes; Faulting; Geophysics; Seismology; Strike-slip faults, Epicenter; Inversion codes; Tomographic analysis, Earthquakes; Location, earthquake; microstructure; San Andreas Fault; seismic hazard; seismic tomography; velocity structure, California; North America; United States, Absolute location errors; Fine-scale structures; Inversion methods; Inversion results; Potential targets; San Andreas fault; Velocity contrasts; Velocity structure https://www.scopus.com/inward/record.uri?eid=2-s2.0-6044257847&doi=10.1029%2f2004GL019398&partnerID=40&md5=98a07d9e7444a741f178c4db525ba8e8 cited By 136 C. Thurber S. Roecker H. Zhang S. Baher W. Ellsworth article Tauxe2003 Paleointensity estimates based on the high quality Thellier-Thellier data from the early Brunhes (420-780 ka) are rare (only 30 in the published literature). The Second Hawaiian Scientific Drilling Project (HSDP2) drill hole recovered submarine volcanics spanning the approximate time period of 420-550 ka. These are of particular interest for absolute paleointensity studies owing to the abundance of fresh submarine basaltic glass, which can preserve an excellent record of ancient geomagnetic field intensity. We present here new results of Thellier-Thellier paleointensity experiments that nearly double the number of reliable paleointensity data available for the early Brunhes. We also show that the magnetizations of the associated submarine basalts are dominated by viscous magnetizations and therefore do not reflect the true ancient geomagnetic field intensity at the time of extrusion. The viscous contamination is particularly severe because of a combination of low blocking temperatures in the basalts and relatively high temperatures in the deeper parts of the drill core. Our new data, when placed on the approximate timescale available for HSDP and HSDP2, are at odds with other contemporaneous paleointensity data. The discrepancy can be reconciled by adjusting the HSDP timescales to be younger by about 35 kyr. © 2003 by the American Geophysical Union. Article 2003 English 15252027 10.1029/2001GC000276 Geochemistry, Geophysics, Geosystems 4 Blackwell Publishing Ltd Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA 92093, United States; U. S. Geological Survey, Golden, Box 25046, MS966, DFC, Denver, CO 80225, United States 2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-1542493807&doi=10.1029%2f2001GC000276&partnerID=40&md5=9a254bc2a7ea752bfd95670c25990959 cited By 29 L. Tauxe J.J. Love article Feigenson2003 The rare earth element (REE) concentrations of lavas from the Hawaiian Scientific Drilling Project (HSDP2) can be used to provide additional constraints on phase equilibria and the nature of the Hawaiian source. Major element analyses separate Mauna Kea lavas into two distinct populations, a high-silica and a low-silica suite. The low-silica samples can be separated stratigraphically into an upper low-silica alkalic series and a low-silica tholeiitic group that occurs deeper in the section. These contrasting groups could result from different extents of source partial fusion, or lithologically distinct source regions, or some combination of both factors. Petrologic modeling is performed to calculate that primary magma compositions contain about 20% MgO, and can be formed by 8-15% melting of a depleted mantle source for low-silica alkalic and high-silica lavas, respectively. The low-silica tholeiites could be generated by higher degrees of melting of a more fertile source. REE ratios and various isotopic systems reinforce the division of the low-SiO2 samples into the upper alkalic series, characterized by high Gd/Yb, and the deeper low-silica tholeiitic group, with low Gd/Yb. REE inverse modeling of fractionation-corrected basalts is consistent with lower degrees of melting to generate the late-stage alkalic lavas, with garnet present as a residual phase. The relatively constant Gd/Yb for low-silica tholeiites suggests that garnet is not an important residual phase during partial melting, implying higher extents of melting. The low-silica tholeiites are characterized by relatively enriched isotopic signatures that are consistent with contributions from a primitive source or from recycled subduction components. High 3He/4He associated with the lowsilica lavas could derive from primitive mantle, mass transfer from the core, or from a refractory lithospheric contribution to a recycled subduction package. However, the combination of major element, REE and isotopic data suggests that the deeper low-silica suite is sampling the relatively fertile, interior part of the Hawaiian plume, whereas the high-silica lavas are extracted from the more depleted periphery; later alkalic lavas are generated from a depleted source as the volcano moves off the hot spot. © 2003 by the American Geophysical Union. 2003 English 15252027 10.1029/2001GC000271 Geochemistry, Geophysics, Geosystems 4 Department of Geological Sciences, Rutgers University, 610 Taylor Road, Piscataway, NJ 08854, United States 2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-0141828869&doi=10.1029%2f2001GC000271&partnerID=40&md5=19955926da5f90d4601cbb82c6ff5db2 cited By 43 M.D. Feigenson L.L. Bolge M.J. Carr C.T. Herzberg article Steveling2003 A quasi-continuous magnetic log has been obtained in the Hawaii Scientific Drilling Project 2 (HSDP-2) between 600 m and 1800 m, which corresponds to a time interval of approximately 350 ka to 480 ka. A tri-axial borehole magnetometer was employed to measure the horizontal and vertical magnetic fields. Measurements were taken in downhole and uphole runs, with a good correlation between the two. In a first step the logs were corrected for the transfer function of the employed low-pass filter and then for the logging depths. To calculate rock magnetizations from magnetic components, we used a multidisk cylindrical model for the penetrated rocks. The disk thickness corresponds with 0.1 m to the logging sampling rate. Magnetic borehole logging in the HSDP-2 hole has established the following: Massive lava flows can be distinguished from those with prevailing hyaloclastites and enables us to supplement the lithology, especially in depth intervals with poor core recovery. The inclinations of rock magnetization derived from the magnetic log agree well with those measured in core samples from HSDP-2 hole. The same applies to magnitudes of magnetizations from logging, as the sum of induced and remanent magnetizations, with laboratory determinations of the remanent magnetizations of core samples. We observe a distinct discrepancy between the local present-day geocentric axial dipole (GAD) inclination of 35.6° and the mean logging inclination of 22.7°. Furthermore, a systematic inclination decrease with depth is observed. Logging and core inclinations in HSDP-2 can be brought into agreement with core inclinations in the HSDP-1 pilot hole by shifting depths of HSDP-1 100 m downward. The correlation of inclination data between the two boreholes and the known age-depth relation of HSDP-1 is used to reexamine the "age versus depth" model curve for Mauna Kea of Sharp et al. (manuscript in preparation, 2003). We identify tentatively two logged inclination minima with excursion of the geomagnetic field in Brunhes, namely, "Levantine" at 360-370 ka and "Unknown" at 400-420 ka. © 2003 by the American Geophysical Union. 2003 English 15252027 10.1029/2002GC000330 Geochemistry, Geophysics, Geosystems 4 Institut für Geophysik, Herzberger Landstrasse 180, 37075 Goettingen, Germany; BGR, Stilleweg 2, 30655 Hannover, Germany 4 https://www.scopus.com/inward/record.uri?eid=2-s2.0-36048943437&doi=10.1029%2f2002GC000330&partnerID=40&md5=6947172fec0e9dfc898aed531c18380b cited By 10 E. Steveling J.B. Stoll M. Leven article Althaus2003 [1] We have determined concentrations and isotopic compositions of all noble gases in olivine phenocrysts from the Hawaii Scientific Drilling Project (HSDP) drill core, comprising Mauna Loa lavas in the top 247 m and Mauna Kea lavas down to the preliminary depth of 3109 m. Our aim was to describe the long-term isotopic evolution of noble gases over a significant time fraction of the active life of a major Hawaiian volcano. The He isotopic signature displays a clear temporal trend: 3He/4He ratios increase from MORBlike 9 RA in the youngest lavas to 15 RA in the Mauna Loa section and from ̃7 RA to ̃12 RA in the subaerial Mauna Kea deposits. They remain close to 12 RA in most of the submarine Mauna Kea samples, except for a few excursions with 3He/4He ratios of up to 21 RA in borehole depths between 2000 and 2600 m. The average 3He/4He ratio of 12 RA is lower than that observed in recent eruptions of Kilauea and Loihi seamount and supports the idea of a concentrically zoned Hawaiian plume [Kurz et al., 1996]. The Ne isotopic signature does not show a temporal evolution. It remains plume-like (plotting close to the Loihi-Kilauea correlation line in a Ne three-isotope diagram) over the whole Mauna Kea section in those samples which are not dominated by air-like Ne. Maximum 20Ne/22Ne and 21Ne/22Ne ratios reach 12.10 ± 0.36 and 0.0360 ±0.0042, respectively. 40Ar/36Ar ratios vary widely between 360 and ̃3300 in the ≥1000°C release steps due to variable atmospheric contributions. In at least one sample, a 40Ar/ 36Ar ratio of 14,300 ±910 demonstrates the presence of a MORB-like Ar component. Kr and Xe isotopic compositions are atmospheric throughout. We discuss several possibilities on how to explain the isotopic trends of the noble gases and their correlation to other geochemical parameters. Simple admixture of MORB-like noble gases to the plume component cannot account for the observations. We favor a model involving early melt extraction from the outer plume sections, followed by radiogenic ingrowth and, possibly, some interaction with ambient mantle material. © 2003 by the American Geophysical Union. Article 2003 English 15252027 10.1029/2001GC000275 Geochemistry, Geophysics, Geosystems 4 Blackwell Publishing Ltd 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-28044440283&doi=10.1029%2f2001GC000275&partnerID=40&md5=da027d803303188b40c6858a397dbc7e Cited by: 16 Tilmann Althaus Samuel Niedermann article Wang2003 Oxygen isotope ratios were measured in olivine phenocrysts (̃1 mm diameter), olivine microphenocrysts (generally ̃100-200 mm diameter), glass, and/or matrix from 89 samples collected from depths down to 3079.7 m in the second, and main, HSDP core (HSDP-2). Olivine phenocrysts from 11 samples from Mauna Loa and 34 samples from the submarine section of Mauna Kea volcano have δ18O values that are similar to one another (5.11 ± 0.10%, 1s, for Mauna Loa; 5.01 ± 0.07%, for submarine Mauna Kea) and within the range of values typical of olivines from oceanic basalts (δ18O of ̃5.0 to 5.2%). In contrast, δ18O values of olivine phenocrysts from 20 samples taken from the subaerial section of Mauna Kea volcano (278 to 1037 mbsl) average 4.79 ± 0.13%. Microphenocrysts in both the subaerial (n = 2) and submarine (n = 24) sections of Mauna Kea are on averagẽ0.2% lower in δ18O than phenocrysts within the same stratigraphic interval; those in submarine Mauna Kea lavas have an average δ18O of 4.83 ± 0.11%. Microphenocrysts in submarine Mauna Kea lavas and phencrysts in Mauna Loa lavas are the only population of olivines considered in this study that are typically in oxygen isotope exchange equilibrium with coexisting glass or groundmass. These data confirm the previous observation that the stratigraphic boundary between Mauna Loa and Mauna Kea lavas defines a shift from "normal" to unusually low δ18O values. Significantly, they also document that the distinctive 18O-depleted character of subaerial Mauna Kea lavas is absent in phenocrysts of submarine Mauna Kea lavas. Several lines of evidence suggest that little if any of the observed variations in δ18O can be attributed to subsolidus alteration or equilibrium fractionations accompanying partial melting or crystallization. Instead, they reflect variable proportions of an 18O-depleted source component or contaminant from the lithosphere and/or volcanic edifice that is absent in or only a trace constituent of subaerial Mauna Loa lavas, a minor component of submarine Mauna Kea lavas, and a major component of subaerial Mauna Kea lavas. Relationships between the δ18O of phenocrysts, microphenocrysts, and glass or groundmass indicate that this component (when present) was added over the course of crystallization-differentiation. This process must have taken place in the lithosphere and most likely at depths of between ̃5 and 15 km. We conclude that the low-δ18O component is either a contaminant from the volcanic edifice that was sampled in increasingly greater proportions as the volcano drifted off the center of the Hawaiian plume or a partial melt of low-δ18O, hydrothermally altered perdotites in the shallow Pacific lithosphere that increasingly contributed to Mauna Kea lavas near end of the volcano's shield building stage. The first of these alternatives is favored by the difference in δ18O between subaerial and submarine Mauna Kea lavas, whereas the second is favored by systematic differences in radiogenic and trace element composition between higher and lower δ18O lavas. Copyright 2003 by the American Geophysical Union. 2003 English 15252027 10.1029/2002GC000406 Geochemistry, Geophysics, Geosystems 4 Division of Geological and Planetary Sciences, California Institute of Technology, M/C 100-23, Pasadena, CA 91125, United States 8 https://www.scopus.com/inward/record.uri?eid=2-s2.0-21644473331&doi=10.1029%2f2002GC000406&partnerID=40&md5=fa83ab9c65a9d4aeb7480cabab67f3a5 cited By 31 Z. Wang N.E. Kitchen J.M. Eiler conference Takahashi2003563 The first production test of methane hydrate layers was carried out at the Mackenzie Delta in the Canadian Arctic. Three wells, named JAPEX/JNOC/GSC et al. Mallik 3L-38, 4L-38 and 5L-38, were drilled through hydrate layers at depths of approximately 900-1100m beneath 640m of permafrost on a line at 40m spacing. Coring, logging, various scientific experiments and production testing were performed over a 79-day period from December 2001 to March 2002. This research project was funded by participants from Japan, Canada, US, Germany and India. The Geological Survey of Canada (GSC) was the coordinator of the science program and Japan National Oil Corporation (JNOC) along with Japan Petroleum Exploration Co. (JAPEX) were the operators. JAPEX Canada Ltd., a subsidiary of JAPEX, acted as the legal operator in Canada and Canadian Petroleum Engineering Inc. (CPE) was retained to provide JAPEX with operational management for the remote arctic environment. The production testing was achieved using two testing methods. Six short duration depressurization tests were conducted using Schlumberger's Modular Dynamic Formation Tester (MDT). A longer duration, thermal stimulation test was carried out by circulating hot fluid past the hydrate layers. An extensive research program was conducted to monitor the formation response to the testing. Cross well tomography surveys were conducted from the observation wells before and during the testing. The post-test wireline log response was compared with pre-test log. The wellbore temperatures were monitored on all wells using fiber-optic cables. These data are valuable for improving the reservoir simulation models to assess gas hydrate production. A practical model is essential for a country such as Japan that has been seeking to economically develop deep water marine gas hydrates off its coast. This paper describes the field operation, explaining how all the programs were accomplished successfully in the limited operational period. The full research gas hydrate research program being conducted at the Mallik site is ongoing with a scheduled public release of the results expected on or before August 2004. © 2003, Offshore Technology Conference 2003 English 9781555632502 01603663 10.4043/15124-ms Proceedings of the Annual Offshore Technology Conference 2003-May Offshore Technology Conference 563-572 Japan Petroleum Exploration Co., Ltd, Brazil; Japan National Oil Corporation, Brazil; Canadian Petroleum Engineering Inc., Brazil Gas hydrates; Gas industry; Gasoline; Hydration; Offshore oil well production; Offshore oil wells; Offshore technology; Oil well logging; Well testing, Gas-hydrate production; Geological Survey of Canada; Japan national oil corporations; Operational management; Petroleum exploration; Reservoir simulation model; Scientific experiments; Thermal stimulation tests, Software testing https://www.scopus.com/inward/record.uri?eid=2-s2.0-85056137093&doi=10.4043%2f15124-ms&partnerID=40&md5=7c32ce928fb4f256c9bea25550ad5f58 cited By 16 H. Takahashi T. Yonezawa E. Fercho article FISCHER2003347 Long Valley Exploratory Well, drilled into the Resurgent Dome at Long Valley Caldera (California) to explore the potential of geothermal power in an active magmatic system, achieved temperatures of only ca. 100°C at 2500–3000 m depth, well below the range expected atop an active magma chamber. Open fissures encountered at 2600 m depth are coated by mm-sized idiomorphic quartz crystals with first- and second-order growth discontinuities. Specific growth defects indicating rapid crystallization reflect sudden changes in SiO2 supersaturation. Fluid inclusions contain low salinity (0–5 wt% NaCl) and low CO2 (<3 mole%) aqueous fluids, with V–L homogenization temperatures of 300–350°C, indicating trapping at more than 200°C above the ambient temperatures measured within the borehole today. Fluid composition and inclusion density varies between and within the growth zones, reflecting progressive changes in the hydrothermal system during crystallization. Episodic crystallization from supersaturated fluids is interpreted to reflect sudden changes in the convection pattern, presumably induced by seismic activity, with a more recent and dramatic reorganization resulting in convective cooling. The quartz crystals are sensitive recorders of the earlier higher temperature history, unaffected by the present-day situation. 2003 0377-0273 https://doi.org/10.1016/S0377-0273(03)00176-8 Journal of Volcanology and Geothermal Research 127 347-363 3 Long Valley Caldera, hydrothermal system, thermal history, fluid inclusions, quartz crystallization, open fissures https://www.sciencedirect.com/science/article/pii/S0377027303001768 Crustal Unrest in Long Valley Caldera, California: New interpretations from geophysical and hydrologic monitoring and deep drilling M. Fischer K. Röller M. Küster B. Stöckhert V.S. McConnell article Thurber2003717 A pair of papers in 1976 lead-authored by Kei Aki heralded the beginning of the field of seismic tomography of the lithosphere. The 1976 paper by Aki, Christofferson, and Husebye introduced a simple and approximate yet elegant technique for using body-wave arrival times from teleseismic earthquakes to infer the three-dimensional (3-D) seismic velocity heterogeneities beneath a seismic array or network (teleseismic tomography). Similarly, a 1976 paper by Aki and Lee presented a method for inferring 3-D structure beneath a seismic network using body-wave arrival times from local earthquakes (local earthquake tomography). Following these landmark papers, many dozens of papers and numerous books have been published presenting exciting applications of and/or innovative improvements to the methods of teleseismic and local earthquake tomography, many by Aki's students. This paper presents a brief review of these two types of tomography methods, discussing some of the underlying assumptions and limitations. Thereafter some of the significant methodological developments are traced over the past two and a half decades, and some of the applications of tomography that have reaped the benefits of these developments are highlighted. One focus is on the steady improvement in structural resolution and inference power brought about by the increased number and quality of seismic stations, and in particular the value of utilizing shear waves. The paper concludes by discussing exciting new scientific projects in which seismic tomography will play a major role - the San Andreas Fault Observatory at Depth (SAFOD) and USArray, the initial components of Earthscope. 2003 English 00334553 10.1007/PL00012555 Pure and Applied Geophysics 160 Birkhauser Verlag AG 717-737 Dept. of Geology/Geophysics, Univ. of Wisconsin-Madison, 1215 W. Dayton St., Madison, WI 53706, United States 3-4 body wave; earthquake; lithospheric structure; seismic tomography; seismic velocity; teleseismic wave https://www.scopus.com/inward/record.uri?eid=2-s2.0-0037343015&doi=10.1007%2fPL00012555&partnerID=40&md5=a90082100f3995377520c91bf0303d0d cited By 15 article Majorowicz200345 Analysis of data from 32 industrial exploration wells in the Mallik field and surrounding area in the Mackenzie Delta-Beaufort Sea region allowed construction of temperature-depth profiles using regionalheat-flowvalues, temperature at the base ofice-bearing permafrost, and model so thermal conductivity with depth. An analysis of the stability conditions for methane hydrate showed that it is stable in the Mallik field area and that the depth to the base of the methane hydrate stability zone can be as deep as 1500±100minareas of thick permafrost.The depth to the base of the methane hydrate stabilityzone, calculated in this study using reconstructed temperature-depth profiles, was found in a majority of the wells to be 50-150 m deeper than that previously determined using linear temperature profiles and a constant thermal conductivity with depth. 2003 English 00687626 Bulletin of the Geological Survey of Canada 45-56 Northern Geothermal Consultants, 105 Carlson Close, Edmonton, AB, T6R 2J8, Canada; Geological Survey of Canada, 601 Booth Street, Ottawa, ON K1A 0E8, Canada 544 https://www.scopus.com/inward/record.uri?eid=2-s2.0-72249123141&partnerID=40&md5=5ca86d6b0cac044138a715024dfc9617 cited By 1 J.A. Majorowicz S.L. Smith article Huang2003 [1] The temporal geochemical variations defined by lavas erupted throughout the growth of a single volcano provide important information for understanding how the Hawaiian plume works. The Hawaii Scientific Drilling Project (HSDP) sampled the shield of Mauna Kea volcano to a depth of 3100 meters below sea level during Phase 2 of the HSDP. Incompatible element abundance ratios, such as La/Yb, Sm/ Yb, Nb/Zr, and Ti/Zr, in conjunction with SiO2 abundance and radiogenic isotopic ratios, especially He and Pb, in the reference sample suites of the Mauna Kea portion of cores from Phases 1 and 2 of the HSDP define three distinct geochemical groups. The upper 550 m of Mauna Kea lavas in the Phase 2 core include the Postshield Group with eruption ages of ̃200 ka to &lt;370 ka. These lavas have relatively low SiO2 content, 3He/4He and 206Pb/204Pb, and they define a trend to relatively high La/Yb, Sm/Yb, and Nb/Zr. The eruption of these lavas coincides with migration of the Mauna Kea shield off the hot spot. As a result, extent of melting decreased, melt segregation occurred at greater depth, within the garnet stability field, and a geochemically distinct component associated with the periphery of the plume was sampled. Deeper in the Phase 2 core two other geochemical groups of lava are intercalated. One group has relatively low SiO2 abundance and high Nb/Zr Ti/Zr, 3He/4He and high 208Pb/204Pb at a given 206Pb/204Pb. These are distinctive geochemical characteristics of lavas erupted at Loihi seamount. Variations in incompatible element abundance ratios (e.g., Sm/Yb versus Nb/Zr and La/Yb versus Ti/Zr) define mixing trends between these low SiO2 lavas (Loihi-type) and lavas belonging to a high SiO2 group that are the dominant lava type in the shield part of the core (Kea-type). These two groups are presumed to reflect components intrinsic to the plume. Correlations of incompatible element abundance ratios, such as La/Nb, with radiogenic isotope ratios show that Hawaiian shields contain different proportions of geochemically distinctive components. The Koolau shield contains a recycled sedimentary component that is not present in the Mauna Kea shield. The anomalously high Ba/Th in Hawaiian lavas is inferred to be a source characteristic. Ba/Th is correlated with some radiogenic isotope ratios in Kilauea and Mauna Loa lavas, but there is no correlation in Mauna Kea lavas which range in Ba/Th by a factor of 2.6. Copyright 2003 by the American Geophysical Union. Article 2003 English 15252027 10.1029/2002GC000322 Geochemistry, Geophysics, Geosystems 4 Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, United States 6 https://www.scopus.com/inward/record.uri?eid=2-s2.0-0037926609&doi=10.1029%2f2002GC000322&partnerID=40&md5=638f32ef4969c896ea182af049d85a79 cited By 75 S. Huang F.A. Frey article Micarelli2003275 In the frame of the Corinth Rift Laboratory project, which aims to understand the relation between stress, strain and fluid flow in an extensional context, three normal faults have been studied and sampled in the south-western sector of the Gulf of Corinth. Two of these faults (the Pirgaki and Helike faults) juxtapose carbonate pre-rift sediments and syn-rift conglomerates at outcrop, and the third (the Aigion fault) has been drilled and cored at 760 m depth. The distance between the faults is around 4 km, and the offsets are approximately 1000, 700 and 170 m, respectively. The fault damage zones and cores of the analysed faults exhibit different geometry, size and textural characteristics. In general, it has been assessed that fault cores behave as near-impermeable barriers to transverse fluid flow, whereas highly fractured damage zones act mostly as conduits for nearly along-strike flow. Different types of fault rocks are exposed along the main faults; these include cataclasite, ultra-cataclasite, fault breccia and gouge, with random or foliated fabrics. Along the Pirgaki fault zone only, fault rock micro-fabrics have been related to multiple tectonic episodes. The results of our work also emphasise that the current conditions of deformation, in this sector of the Gulf of Corinth, are responsible for the development of a system of extension fractures that is only partially sealed. These fractures mainly control the permeability structure of the analysed fault zones and furnish information on the stress field acting in the area. Furthermore, their orientation and distribution indicate that they are consistent with a deformation pattern resulting from active extension. © 2003 Elsevier Ltd. All rights reserved. Article 2003 English 02643707 10.1016/S0264-3707(03)00051-6 Journal of Geodynamics 36 Elsevier Ltd 275 – 303 1-2 Greece; Gulf of Corinth; deformation; faulting; neotectonics; rift zone; seismicity; tectonics https://www.scopus.com/inward/record.uri?eid=2-s2.0-0037962295&doi=10.1016%2fS0264-3707%2803%2900051-6&partnerID=40&md5=aac16d597059973447ab88c7904dcffd Cited by: 88 L. Micarelli I. Moretti J.M. Daniel article Sorey2003165 Since 1978, volcanic unrest in the form of earthquakes and ground deformation has persisted in the Long Valley caldera and adjacent parts of the Sierra Nevada. The papers in this special volume focus on periods of accelerated seismicity and deformation in 1980, 1983, 1989-1990, and 1997-1998 to delineate relations between geologic, tectonic, and hydrologic processes. The results distinguish between earthquake sequences that result from relaxation of existing stress accumulation through brittle failure and those in which brittle failure is driven by active intrusion. They also indicate that in addition to a relatively shallow (7-10-km) source beneath the resurgent dome, there exists a deeper (∼15-km) source beneath the south moat. Analysis of microgravimety and deformation data indicates that the composition of the shallower source may involve a combination of silicic magma and hydrothermal fluid. Pressure and temperature fluctuations in wells have accompanied periods of crustal unrest, and additional pressure and temperature changes accompanying ongoing geothermal power production have resulted in land subsidence. The completion in 1998 of a 3000-m-deep drill hole on the resurgent dome has provided useful information on present and past periods of circulation of water at temperatures of 100-200°C within the crystalline basement rocks that underlie the post-caldera volcanics. The well is now being converted to a permanent geophysical monitoring station. © 2003 Elsevier B.V. All rights reserved. 2003 English 03770273 10.1016/S0377-0273(03)00168-9 Journal of Volcanology and Geothermal Research 127 Elsevier 165-173 U..Geological Survey, 161 Sausal Drive, Portola Valley, CA 94028, United States; Oregon Dept. of Geol./Mineral Rsrc., Portland, OR, United States; U.S. Geological Survey, Vancouver, WA, United States 3-4 Earthquakes; Hydrology; Pressure effects; Seismology; Thermal effects, Hydrothermal fluids, Volcanoes, borehole; caldera; geodesy; hydrothermal system; research; volcanic earthquake; volcano, California; Long Valley Caldera; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-0141974826&doi=10.1016%2fS0377-0273%2803%2900168-9&partnerID=40&md5=daeb60c711437f430b98dd3c99ff143c cited By 21 M.L. Sorey V.S. McConnell E. Roeloffs article Rolandone2003 We use temperature profiles from 4 deep (>1600 m) boreholes across Canada to determine ground surface temperature histories (GSTH's) through and after the Last Glacial Maximum (LGM). Inversion yields the temperature history at the base of the glacier and the surface temperature evolution after the glacial retreat. The results indicate geographic differences in basal temperature history across the Ice Sheet. During the Last Glacial Maximum, temperatures at the base of the Ice Sheet were lower in eastern Canada, at the southeastern edge of the glacier, than in central Canada, southwest of the glacier center. At all sites, basal temperatures were above the melting point of ice during and after the LGM, which may explain the highly unstable character of the Ice Sheet. The GSTH's are consistent with information on the history of the Laurentide ice sheet and provide quantitative constraints on glacier flow dynamics. 2003 English 00948276 10.1029/2003GL018046 Geophysical Research Letters 30 American Geophysical Union CRY 3-1 - 3-4 Berkeley Seismological Laboratory, UC Berkeley, 215 McCone Hall, Berkeley, CA 94720, United States; GEOTOP-UQAM-McGill, Ctr. Rech. Geochemie/en Geodynamique, Univ. du Quebec a Montreal, Montréal, H3C 3P8, Canada; Inst. de Physique du Globe de Paris, 4 Place Jussieu, Paris cedex 05 75252, France 18 Boreholes; Glaciers; Ice; Melting; Atmospheric temperature; Glacial geology; Surface properties, Melting points; Borehole temperature; Geographic difference; Ground surface temperature; Last Glacial Maximum; Laurentide ice sheets; Surface temperatures; Temperature history; Temperature profiles, Geophysics; Ice, basal temperature; Last Glacial Maximum; Laurentide Ice Sheet; paleoclimate, North America https://www.scopus.com/inward/record.uri?eid=2-s2.0-0348172344&doi=10.1029%2f2003GL018046&partnerID=40&md5=17fd5a4e2b5b04b5b074e81991bb6d19 cited By 27 F. Rolandone J.-C. Mareschal C. Jaupart article Eisele2003 [1] We analyzed Pb isotopic compositions of 50 samples from the HSDP-2 drill hole, covering the time interval 180 to 550 kyr B.P. in the stratigraphic record of Mauna Kea. All analyses were corrected for instrumental bias using a triple-spike technique. The aims of this study are to document temporal changes in sources contributing to Mauna Kea and to investigate how these may relate to the chemical structure of the Hawaiian plume. Lead isotopic compositions of the lavas have 206Pb/204Pb ratios ranging from 18.41 to 18.63, 207Pb/204Pb from 15.47 to 15.49, and 208Pb/ 204Pb from 37.97 to 38.22. In 207Pb/204Pb- 206Pb/204Pb space, the samples display a broad linear array, while three distinct arrays are found in 208Pb/ 204Pb-206Pb/204Pb space. These arrays can clearly be distinguished by their 208Pb/204Pb ratios and are referred to as "Kea-lo8," "Kea-mid8," and "Kea-hi8." The 206Pb/204Pb isotope ratios exhibit rapid shifts by ̃0.2 over 100 m depth intervals, and jumps from one Pb isotope array to another and back in less than ̃100 m depth. Despite these rapid Pb isotope fluctuations, a particular Pb isotope array dominates over periods of several tens to hundreds of kiloyears. We interpret the Pb isotope arrays found in HSDP-2 in terms of mixing of end-members lying along the radiogenic and unradiogenic extensions of the arrays. At the radiogenic extension the three HSDP-2 arrays converge to a common end-member. The lower extensions of the arrays diverge in three directions, each with different 208Pb/ 204Pb ratios. This topology suggests that the HSDP-2 arrays were produced by mixing of at least four end-members. The origin of these end-members was investigated using Monte Carlo simulations of a Pb isotope evolution model. The simulations suggest that the common radiogenic end-member of the three Pb isotope arrays contains material with elevated m values and has a relatively young age (<1.5 Ga). Such a signature can be plausibly interpreted in terms of the presence of recycled oceanic crust in the source. The HSDP-2 Kea-lo8, Keamid8, and Kea-hi8 Pb isotope arrays dominate over different time periods and can be related to the displacement of Mauna Kea relative to the plume center over time. The Kea-lo8 array is present between ̃180 and 370 ka and samples more peripheral parts of the plume, while the Kea-mid8 and Kea-hi8 arrays occur in the deeper parts of the core (̃370 to 550 kyr ago), when Mauna Kea was closer to the plume center. Over the time intervals when each array dominates, we derive corresponding "lengths" of materials in the source by integrating the estimated upwelling velocity across the plume. These calculations suggest Pb isotope heterogeneities of at least several tens of kilometers in vertical length within the Hawaiian plume. The Pb isotope arrays may correspond to relatively small-scale heterogeneities derived from the D″ layer in the lower mantle. © 2003 by the American Geophysical Union. Article 2003 English 15252027 10.1029/2002GC000339 Geochemistry, Geophysics, Geosystems 4 5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-2142757212&doi=10.1029%2f2002GC000339&partnerID=40&md5=d28bdb295b3e7b3104019db9b1430df4 Cited by: 138; All Open Access, Bronze Open Access Jürgen Eisele Wafa Abouchami Stephen J.G. Galer Albrecht W. Hofmann article Moretti2003323 The Gulf of Corinth is often considered as a typical example of a more or less simple half graben with major border faults to the south and a flexure of the northern shore. This paper reviews new data, especially subsurface data, from both onshore and offshore, compiled or acquired through the Corinth Rift Laboratory EEC project. This data indicate that (1) the Gulf of Corinth is bordered both north and south by active faults; (2) there is a lot of them, and not only the one bordering the Peloponnese coastline are still active; and (3) distinct opening phases may be recognized on the area. During the first phase, the depocenter was located near the northern shore, whereas during the most recent phase, and only in the centre and the eastern sector, the depocenter moved towards the southern shore. Furthermore, active tectonic, in this western sector, is characterised by a general uplift of the Peloponnese that leads to the formation of new faults, i.e. the Doumena, Aigion and Helike faults and to selective reactivation of older ones such as the Pirgaki fault. We suggest that this current tectonic phase started about 150-120 000 years ago in the Aigion area and about 350 000 years ago eastward (Corinth-city) and that it represents a third opening phase during the growth of the Gulf of Corinth. © 2003 Elsevier Ltd. All rights reserved. Article 2003 English 02643707 10.1016/S0264-3707(03)00053-X Journal of Geodynamics 36 Elsevier Ltd 323 – 340 1-2 Greece; Gulf of Corinth; active fault; deformation; faulting; graben; neotectonics; rift zone; tectonics https://www.scopus.com/inward/record.uri?eid=2-s2.0-0037659797&doi=10.1016%2fS0264-3707%2803%2900053-X&partnerID=40&md5=d646e9c458b7dcd66112a459e50ea509 Cited by: 132 Isabelle Moretti D. Sakellariou V. Lykousis L. Micarelli article Büttner200323 The objectives of this paper are an understanding of the thermal and hydraulic field because of a negative temperature gradient and cold temperatures in the 1-km-deep borehole of the Hawaiian Scientific Drilling Project (HSDP), located near the coast line. The temperature pattern is attributed to a superposition of thermal and hydraulic processes. In the deeper borehole (HSDP-2, depth 3.1 km) detailed temperature monitoring was performed. Temperature measurements reveal two different thermal regimes. The upper part is characterised by cold temperatures and a negative temperature gradient similar to those observed in the shallow pilot borehole. Below 1100 m, increasing temperatures are observed. Different processes, such as topographically driven groundwater flow, ingress of salt water and conductive heat flow are investigated by numerical modeling. A pure conductive scenario fails to match the temperature measurements, implying that both borehole sections are overprinted by advective conditions. Coupled fluid and heat flow modeling with solute transport yield results that agree with observed temperatures. The results of these simulations suggest that meteoric water flow from the mountain range controls the thermal conditions in the upper part of the borehole. Below this level, the thermal regime is additionally affected by circulation of salt water from the nearby ocean. Each of these flow systems has been observed at other locations: topographically driven fresh water at locations with pronounced topography and ingress of salt water is typical for islands or coastal areas. At Hawaii, they coincide and influence each other, resulting in a salt water interface occurring at greater depth than expected. © 2003 Elsevier B.V. All rights reserved. Article 2003 English 00401951 10.1016/S0040-1951(03)00197-5 Tectonophysics 371 Elsevier B.V. 23 – 40 1-4 Hawaii; Mauna Kea; United States; borehole; heat flow; heat transfer; hydraulic property; temperature gradient; thermal structure https://www.scopus.com/inward/record.uri?eid=2-s2.0-0042328346&doi=10.1016%2fS0040-1951%2803%2900197-5&partnerID=40&md5=606285c48d0179e06af7db5641176264 Cited by: 12 Grit Büttner Ernst Huenges article Cornet20031257 Relationships between flow distributions and mechanical opening in a single natural fracture are investigated in situ through field experiments, at a scale of about 1 m, in a granitic quarry. Experiments have been conducted at various injection flow-rates while the normal stress applied to the fracture was controlled by hydraulic flat jacks. Variations of the collected flow-rate (monitored through contiguous flow collectors distributed along the fracture periphery) with the injection pressure are fully reproducible. They show that the fracture opens only above a threshold pressure which increases with the externally applied stress. This threshold is non-zero with no applied flat jacks pressure which raises questions on the reliability of hydraulic jacking techniques for the measurement of the normal stress on preexisting fractures. It is shown that equivalent hydraulic aperture and mechanical opening are comparable only above a critical mean fracture opening estimated to be around 15-20 μm for the tested granite. For mean fracture openings smaller than this value, the standard time scale used for stress measurements distorts the results. It is also shown that channeling effects may control flow away from the injection hole so that the hydraulic jacking stress measurement technique may overestimate the mean normal stress acting on the fracture plane by as much as 4 MPa. It is concluded that hydraulic testing techniques for normal stress measurements should not include results from the fracture opening phase. Moreover, criteria should be established for validating results from the closing phase in order to demonstrate the absence of channelling effects. Finally, it is shown that, because of the elastic response of the rock, water injection in a fracture system decreases the interstitial pressure ahead of the increasing pressure front associated with the water flow. © 2003 Elsevier Ltd. All rights reserved. Article 2003 English 13651609 10.1016/S1365-1609(03)00120-5 International Journal of Rock Mechanics and Mining Sciences 40 Elsevier BV 1257 – 1270 7-8 Elasticity; Fracture; Granite; Quarrying; Water; Hydromechanical behavior; fracture flow; hydromechanics; in situ stress; rock mechanics; stress measurement; Rock mechanics https://www.scopus.com/inward/record.uri?eid=2-s2.0-0142230374&doi=10.1016%2fS1365-1609%2803%2900120-5&partnerID=40&md5=be0cac1552fd8faed0d4c593d3aa6ff6 Cited by: 50 F.H. Cornet L. Li J.-P. Hulin I. Ippolito P. Kurowski article Battaglia2003219 We model the source of inflation of Long Valley caldera by combining geodetic and micro-gravity data. Uplift from GPS and leveling, two-color EDM measurements, and residual gravity change determinations are used to estimate the intrusion geometry, assuming a vertical prolate ellipsoidal source. The U.S. Geological Survey occupied the Long Valley gravity network six times from 1980 to 1985. We reoccupied this network twice, in the summer of 1998 (33 stations), and the summer of 1999 (37 stations). Before gravity data can be used to estimate the density of the intrusion, they must be corrected for the effect of vertical deformation (the free-air effect) and changes in the water table. We use geostatistical techniques to interpolate uplift and water table changes at the gravity stations. The inflation source (a vertical prolate ellipsoid) is located 5.9 km beneath the resurgent dome with an aspect ratio equal to 0.475, a volume change from 1982 to 1999 of 0.136 km3 and a density of around 1700 kg/m3. A bootstrap method was employed to estimate 95% confidence bounds for the parameters of the inflation model. We obtained a range of 0.105-0.187 km3 for the volume change, and 1180-2330 kg/m3 for the density. Our results do not support hydrothermal fluid intrusion as the primary cause of unrest, and confirm the intrusion of silicic magma beneath Long Valley caldera. Failure to account for the ellipsoidal nature of the source biases the estimated source depth by 2.9 km (a 33% increase), the volume change by 0.019 km3 (a 14% increase) and the density by about 1200 kg/m3 (a 40% increase). © 2003 Elsevier B.V. All rights reserved. 2003 English 03770273 10.1016/S0377-0273(03)00171-9 Journal of Volcanology and Geothermal Research 127 Elsevier 219-245 Department of Geophysics, Stanford University, Stanford, CA 94305-2215, United States; U.S. Geological Survey, 345 Middlefield Road, Menlo Park, CA 94025, United States 3-4 Deformation; Gravitational effects; Microgravity processing, Ellipsoidal sources, Geology, caldera; geodetic datum; geometry; geostatistics; GPS; gravity; modeling; uplift, California; Long Valley Caldera; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-0037477680&doi=10.1016%2fS0377-0273%2803%2900171-9&partnerID=40&md5=8418bc5cc3ccdfcdc51c270b592bf007 cited By 113 M. Battaglia P. Segall C. Roberts article Claeys20031299 The suevite breccia of the Chicxulub impact crater, Yucatàn, Mexico, is more variable and complex in terms of composition and stratigraphy than suevites observed at other craters. Detailed studies (microscope, electron microprobe, SEM, XRF) have been carried out on a noncontinuous set of samples from the drill hole Yucatàn 6 (Y6) located 50 km SW from the center of the impact structure. Three subunits can be distinguished in the suevite: the upper unit is a fine-grained carbonate-rich suevite breccia with few shocked basement clasts, mostly altered melt fragments, and formerly melted carbonate material; the middle suevite is a coarse-grained suevite with shocked basement clasts and altered silicate melt fragments; the lower suevite unit is composed of shocked basement and melt fragments and large evaporite clasts. The matrix of the suevite is not clastic but recrystallized and composed mainly of feldspar and pyroxene. The composition of the upper members of the suevite is dominated by the sedimentary cover of the Yucatàn target rock. With depth in well Y6, the amount of carbonate decreases and the proportion of evaporite and silicate basement rocks increases significantly. Even at the thin section scale, melt phases of different chemistry can be identified, showing that no widespread homogenization of the melt took place. The melt compositions also reflect the heterogeneity of the deep Yucatàn basement. Calcite with characteristic feathery texture indicates the existence of formerly pure carbonate melt. The proportion of carbonate to evaporite clasts is less than 5:1, except in the lower suevite where large evaporite clasts are present. This proportion constrains the amount of CO2 and SOx released by the impact event. 2003 10.1111/j.1945-5100.2003.tb00315.x Meteoritics and Planetary Science 38 1299-1317 Department of Geology, Vrije Universiteit Brussel, Pleinlaan 2, Brussels B-1050, Belgium; ZERIN (Ctr. for Ries Crater/Impact), Vordere Gerbergasse 3, Nördlingen 86720, Germany; Institute of Geology (UNAM), Ciudad Universitaria, Apartado Postal 70-296, México, DF 04510, Mexico; Institut für Mineralogie, Museum für Naturkunde, Humboldt-Universität zu Berlin, Invalidenstrasse 43, Berlin 10099, Germany 9 https://www.scopus.com/inward/record.uri?eid=2-s2.0-0742323356&doi=10.1111%2fj.1945-5100.2003.tb00315.x&partnerID=40&md5=090badb0b9701f0eb3478875fb8fc721 cited By 59 P. Claeys S. Heuschkel E. Lounejeva-Baturina G. Sanchez-Rubio D. Stöffler article Russell2003133 Lake Bosumtwi is one of the most widely studied palaeoclimate archives in West Africa. Results from numerous AMS 14C dates of samples from four piston cores from Lake Bosumtwi show that an abrupt sedimentary transition from a mid-Holocene sapropel to calcareous laminated muds occurred at about 3200 cal yr B.P. High-resolution analyses of the nitrogen isotopic composition of organic matter across this transition confirm its abrupt nature, and suggest that the change may signal a step toward increased aridity and intensified surface winds that affected western equatorial Africa from Ghana to the Congo basin. Northern and Eastern Africa experienced a similar abrupt shift toward aridity during the late Holocene, but at about 5000 cal yr B.P., a difference in timing that illustrates the regional nature of climate changes during the Holocene and the importance of feedback mechanisms in regulating Holocene climate variability. Furthermore, an abrupt change at about 3000 cal yr B.P. occurs at several sites adjacent to the tropical and subtropical Atlantic, which may hint at major changes in the surface temperatures of the tropical Atlantic and/or Pacific at this time. © 2003 University of Washington. Published by Elsevier Inc. All rights reserved. Article 2003 English 00335894 10.1016/S0033-5894(03)00065-6 Quaternary Research 60 Academic Press Inc. 133 – 141 2 Ghana; Lake Bosumtwi; aridity; Holocene; lacustrine deposit; nitrogen isotope; paleoclimate; paleolimnology https://www.scopus.com/inward/record.uri?eid=2-s2.0-0141683529&doi=10.1016%2fS0033-5894%2803%2900065-6&partnerID=40&md5=2ffb4e2d8cf77b587a364f5c0a809cba Cited by: 63 James Russell Michael R. Talbot Brian J. Haskell article Taylor2003391 We apply a two-dimensional geothermal model to predict the permafrost and natural gas hydrate structure in theMallik field area, based on two paleoenvironmental scenarios deduced at otherwells in theMackenzieDelta area. ScenarioAindicated a subaerial history throughout theHolocene, and scenario B documented a several thousand year, subaqueous episode during theHolocene followed by recent subaerial exposure. The effects of these histories is limited largely to the 600mthick permafrost zone, with scenarioB predicting a substantial talik. The most defensible scenario can be resolved with ground temperatures or independent paleoenvironmental indicators. The effect of climatewarmingwill be apparent in awarming of the permafrost and, with marine transgression, creation of an underlying talik. Terrestrial methane hydrate deposits remain stable with increasing surface temperatures over several centuries, but the base of gas hydrate stability rises about 2 m after 300 years. 2003 English 00687626 Bulletin of the Geological Survey of Canada 391-401 Geological Survey of Canada, 601 Booth Street, Ottawa, ON, K1A 0E8, Canada 544 https://www.scopus.com/inward/record.uri?eid=2-s2.0-72249115966&partnerID=40&md5=462c6c4ae264f892429da3023a7d1c46 cited By 1 A.E. Taylor article Foulger2003 A temporary network of 69 three-component seismic stations captured a major seismic sequence in Long Valley caldera in 1997. We performed a tomographic inversion for crustal structure beneath a 28 km × 16 km area encompassing part of the resurgent dome, the south moat, and Mammoth Mountain. Resolution of crustal structure beneath the center of the study volume was good down to ∼3 km below sea level (∼5 km below the surface). Relatively high wave speeds are associated with the Bishop Tuff and lower wave speeds characterize debris in the surrounding moat. A low-Vp/Vs anomaly extending from near the surface to ∼1 km below sea level beneath Mammoth Mountain may represent a CO2 reservoir that is supplying CO2-rich springs, venting at the surface, and killing trees. We investigated temporal variations in structure beneath Mammoth Mountain by differencing our results with tomographic images obtained using data from 1989/1990. Significant changes in both Vp and Vs were consistent with the migration of CO2 into the upper 2 km or so beneath Mammoth Mountain and its depletion in peripheral volumes that correlate with surface venting areas. Repeat tomography is capable of detecting the migration of gas beneath active silicic volcanoes and may thus provide a useful volcano monitoring tool. 2003 English 21699313 Journal of Geophysical Research: Solid Earth 108 Blackwell Publishing Ltd ESE 6-1 - 6-16 Volcano Hazards Team, U.S. Geological Survey, 345 Middlefield Rd., Menlo Park, CA 94025, United States; Division of Earth and Ocean Sciences, Nicholas School of the Environment, Duke University, Durham, NC 27708-0235, United States 3 caldera; crustal structure; seismic tomography; seismic velocity; velocity structure, California; Long Valley; Mammoth Mountain; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-0038792042&partnerID=40&md5=ae44916891ad81446ed860b9050ac965 cited By 53 G.R. Foulger B.R. Julian A.M. Pitt D.P. Hill E. Shalev article Ji200349 Ultra high-pressure (UHP) eclogites from Sulu region (China) represent mafic components of the continental crust, which were first subducted to mantle depths greater than 100 km and then exhumed to the earth's surface. Detailed investigation of microstructures, chemical compositions, petrofabrics and seismic properties of the UHP eclogites can provide important information on the operating deformation mechanisms and rheology of subducted continental crust and on the origin of seismic reflections within the upper mantle. We present here results from field, optical and TEM observations, electron back-scattered diffraction (EBSD) measurements and numerical computations of the seismic properties of UHP eclogites collected from fresh surface outcrops at the drill site (Maobei, Donghai County, Jiangsu Province) of the Chinese Continental Scientific Drilling Program (CCSD). Two types of eclogites have been distinguished: Type-1 (coarse-grained) eclogites deformed by recovery-accommodated dislocation creep at the peak metamorphic conditions, and Type-2 (fine-grained) eclogites which are composed of reworked Type-1 materials during recrystallization-accommodated dislocation creep in shear zones which were active during the exhumation of the UHP metamorphic rocks. Both garnet and omphacite in these eclogites deformed plastically and the flow strength contrast between these two constituent minerals is apparently much less than an order of magnitude under the UHP metamorphic conditions. Plasticity of eclogites under UHP conditions can effectively facilitate channeled flow along the interplate shear zone. The preservation of the relict crustal materials within the continental lithosphere may produce regionally extensive, strong, seismic reflections in the upper mantle. This may explain the origin of mantle reflections observed in many areas of the world. © 2003 Elsevier B.V. All rights reserved. Article 2003 English 00401951 10.1016/S0040-1951(03)00177-X Tectonophysics 370 Elsevier B.V. 49 – 76 1-4 China; Sulu Belt; eclogite; mantle; microstructure; petrofabric; rheology; seismic reflection; subduction https://www.scopus.com/inward/record.uri?eid=2-s2.0-0042973865&doi=10.1016%2fS0040-1951%2803%2900177-X&partnerID=40&md5=d007e919fe2ba64e1edc8bd7744ef534 Cited by: 94 Shaocheng Ji Kazuko Saruwatari David Mainprice Richard Wirth Zhiqin Xu Bin Xia article Tauxe2003 2003 English 15252027 10.1029/2003GC000564 Geochemistry, Geophysics, Geosystems 4 Scripps Institution of Oceanography, University of California, San Diego, CA 92093, United States; U. S. Geological Survey, Golden, Box 250460, DFC, Denver, CO, 80225, United States 5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-72449194322&doi=10.1029%2f2003GC000564&partnerID=40&md5=e49e534eeeef5c623da657e4445eec79 cited By 0 L. Tauxe J.J. Love inproceedings Kashiwaya2003LongCR 2003 Kenji Kashiwaya incollection 10.1130/0-8137-2369-8.169 { Full article available in PDF version. } 2003 01 9780813723693 10.1130/0-8137-2369-8.169 {Causes and consequences of globally warm climates in the early Paleogene} Geological Society of America https://doi.org/10.1130/0-8137-2369-8.169 Tatiana V. Oreshkina Hedi Oberhaensli article Tapia2003139 A composite high-resolution diatom stratigraphy from three piston cores and one box-core in the deep sub-basin of Lake Titicaca reveals large moisture variations during the past 30 kyr in the Altiplano region. Diatom sequences indicate orbital and millennial-scale variability in water level and salinity. The pelagic freshwater diatom species Cyclotella andina and Cyclotella stelligera dominate Glacial-age sediments, suggesting that the lake was above its present outlet, Generally, wet conditions continued until 11 000 cal yr BP, as indicated by high percentages of freshwater planktonic diatoms. Large pulses of benthic diatom species between about 11 000 and 10 000 cal yr BP suggest brief intervals of large-amplitude declines in lake level. During the early Holocene (10 000-8500 cal yr BP), a freshwater diatom assemblage suggests overflowing conditions. Pelagic freshwater diatoms are replaced ca, 8500 cal yr BP by the salinity-indifferent species Cyclotella meneghiniana and by benthic taxa, indicating the beginning of lake regression. During the mid-Holocene (6000-3500 cal yr BP), the abundance of the saline taxon Chaetoceros muelleri, coupled with high abundances of epiphytic and epipelic diatoms, indicates maximum salinity and lowest lake levels in the entire 30 000 year record. Lake transgression began ca. 4000 cal yr BP, and the lake achieved modern levels by about 1500 cal yr BP. These water-level changes imply changes in effective moisture, most likely resulting from large precipitation changes. Precipitation was high throughout the Last Glacial Maximum (21 000-18 000 cal yr BP), likely due to an enhanced South American Summer Monsoon during peak summer insolation in the Southern Hemisphere. In contrast, the mid-Holocene transition was dryer than today in association with an austral summer insolation minimum and the subsequent weakening of the summer monsoon. © 2003 Elsevier Science B.V. All rights reserved. Conference paper 2003 10.1016/S0031-0182(03)00275-X Palaeogeography, Palaeoclimatology, Palaeoecology 194 139 – 164 1-3 Bolivia; Lake Titicaca; Peru; Bacillariophyta; Chaetoceros; Chaetoceros muelleri; Chaetoceros muelleri; Cyclotella; Cyclotella andina; Cyclotella meneghiniana; Cyclotella stelligera; Cyclotella stelligera; biostratigraphy; diatom; lake level; Last Glacial Maximum; paleoclimate; Quaternary https://www.scopus.com/inward/record.uri?eid=2-s2.0-0038029951&doi=10.1016%2fS0031-0182%2803%2900275-X&partnerID=40&md5=3636d1da4e27fb18d0157fabdbbb9e52 Cited by: 127; All Open Access, Green Open Access Pedro M. Tapia Sherilyn C. Fritz Paul A. Baker Geoffrey O. Seltzer Robert B. Dunbar article Chavarria20031746 The San Andreas Fault Observatory at Depth pilot hole is located on the southwestern side of the Parkfield San Andreas fault. This observatory includes a vertical seismic profiling (VSP) array. VSP seismograms from nearby micro-earthquakes contain signals between the P and S waves. These signals may be P and S waves scattered by the local geologic structure. The collected scattering points form planar surfaces that we interpret as the San Andreas fault and four other secondary faults. The scattering process includes conversions between P and S waves, the strengths of which suggest large contrasts in material properties, possibly indicating the presence of cracks or fluids. 2003 English 00368075 10.1126/science.1090711 Science 302 1746-1748 Division of Earth and Ocean Sciences, Nicholas Sch. Environ./Earth Sci., Duke University, Durham, NC 27708, United States; U.S. Geological Survey, MS977, 345 Middlefield Road, Menlo Park, CA 94025, United States 5651 Cracks; Earthquakes; Fluids; Scattering, Vertical seismic profiling (VSP), Seismology, geological structure; microearthquake; P-wave; S-wave; San Andreas Fault; vertical seismic profile, article; earthquake; electric resistance; geology; material state; priority journal; rock; sediment; United States, California; North America; Parkfield; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-0344305771&doi=10.1126%2fscience.1090711&partnerID=40&md5=deee153cf6ff5ae7bd84013df7f3c4f6 cited By 57 J.A. Chavarria P. Malin R.D. Catchings E. Shalev article Paduano2003259 Fine-resolution fossil pollen and charcoal analyses reconstruct a vegetation and fire history in the area surrounding Lake Titicaca (3810 m, Peru/Bolivia) since ca, 27 500 cal yr BP (hereafter BP). Time control was based on 26 accelerator mass spectrometer (AMS) radiocarbon dates. Seventeen AMS dates and 155 pollen and charcoal samples between ca. 17 500 BP and ca. 3100 BP allow a centennial-scale reconstruction of deglacial and early- to mid-Holocene events. Local and regional fire signals were based on the separation of two charcoal size fractions, ≥ 180 μm and 179-65 μm. Charcoal abundance correlated closely with the proportion of woody taxa present in the pollen spectra. Little or no pollen was detected in the sedimentary record prior to ca. 21 000 BP. Very cold climatic conditions prevailed, with temperatures suggested to be at least 5-8°C cooler than present. Increases in pollen concentration suggest initial warming at ca. 21 000 BP with a more significant transition toward deglaciation ca. 17 700 BP. Between 17 700 BP and 13 700 BP, puna brava is progressively replaced by puna and sub-puna elements. The most significant changes between the Pleistocene and the Holocene floras were largely complete by 13 700 BP, providing an effective onset of near-modern conditions markedly earlier than in other Andean records. Fire first occurs in the catchment at ca. 17 700 BP and becomes progressively more important as fuel loads increase. No evidence is found of a rapid cooling and warming coincident with the Younger Dryas chron. A dry event between ca. 9000 BP and 3100 BP, with a peak between 6000 and 4000 BP, is inferred from changes in the composition of aquatics, and the marsh community as pollen of Cyperaceae is replaced by Poaceae, Apiaceae, Plantago and the shrub Polylepis. Human disturbance of the landscape is evident in the pollen spectra after ca. 3100 BP with the appearance of weed species. © 2003 Elsevier Science B.V. All rights reserved. Conference paper 2003 10.1016/S0031-0182(03)00281-5 Palaeogeography, Palaeoclimatology, Palaeoecology 194 259 – 279 1-3 Bolivia; Lake Titicaca; Peru; Apiaceae; Apiales; Cyperaceae; Plantago; Plantago; Poaceae; Polylepis; Polylepis; deglaciation; fire history; Last Glacial Maximum; paleoclimate; pollen; Quaternary; vegetation history https://www.scopus.com/inward/record.uri?eid=2-s2.0-0038706478&doi=10.1016%2fS0031-0182%2803%2900281-5&partnerID=40&md5=b348d60e553d5eb7dda3b5d91c2c3185 Cited by: 143; All Open Access, Green Open Access Gina M. Paduano Mark B. Bush Paul A. Baker Sherilyn C. Fritz Geoffrey O. Seltzer article Walton2003 [1] The core from the Hawaii Scientific Drilling Project 2 Phase 1 provides a unique opportunity for studying the low-temperature alteration processes affecting basalt in suboceanic-island environments. In hyaloclastites, which make up about one half of the lower 2 km of this core (the portion that accumulated below sea level), these processes have resulted in zones of incipient, smectitic, and palagonitic alteration. The alteration of sideromelane in these hyaloclastites has four distinct outcomes: dissolution, replacement by two different textural varieties of smectite (i.e., reddened and green grain-replacive), and conversion to palagonite. All samples show evidence of the incipient stage of alteration, suggesting that every sample passed through that zone. However, most samples that show palagonitic alteration do not also show evidence of smectitic alteration and vice versa, suggesting these two outcomes represent divergent paths of alteration. Incipient alteration (1080 to 1335 m depth) includes fracturing and mechanical reduction of porosity from 40-45% to about 20-30%; growth of one form of pore-lining smectite; dissolution of sideromelane; and formation of sideromelane-grain replacements consisting of Fe-hydroxide-strained smectite, titaniferous nodules, and tubules. DNA-specific stains and morphological features indicate that tubules are the result of microbial activity. Smectitic alteration (1405 to 1573 m) includes growth of a second variety of pore-lining smectite, pore-filling and grain-replacing smectite, and cements of phillipsite and Ca-silicate minerals. Palagonitic alteration (1573 m to the deepest samples) includes replacement of margins of shards with palagonite and growth of pore-filling chabazite. The porosity is reduced by cementation to less than 4% at 1573 m. Porosity does not decrease further down hole, nor does the thickness of palagonite rims on shards increase through the zone of palagonitic alteration. In these samples, palagonite is not an intermediate alteration product in the development of smectite. Rather, in hyaloclastites from the HSDP core, palagonite has formed after all observed smectites. Current downhole temperatures at the boundaries between the three alteration zones are in the range from 12° to 15°C, suggesting that geochemical thresholds or vital effects, not temperature conditions, control different outcomes of alteration. © 2003 by the American Geophysical Union. 2003 English 15252027 10.1029/2002GC000368 Geochemistry, Geophysics, Geosystems 4 Department of Geology, University of Kansas, 1475 Jayhawk Boulevard, Lawrence, KS 66045, United States; Department of Geology, University of California, 1 Shields Boulevard, Davis, CA 95616, United States 5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-7544228116&doi=10.1029%2f2002GC000368&partnerID=40&md5=cb00df94ccd745bacbedb5b53fe56ec5 cited By 74 A.W. Walton P. Schiffman article Prokopenko2003623 The paper presents new biogenic silica (BiSi) and total organic carbon (TOC) data for the past 130 kyr from BDP-98 and BDP-96-2 cores, respectively, showing a distinct climate periodicity correlated with Late Pleistocene rhythms. The high-resolution sedimentary records from Lake Baikal allow approaching the problem of the length of the last interglacial and stability of its climate in the Northern Hemisphere. The Siberian archives for the interval of 70 to 130 kyr contain brief sub-Milankovitch millenial-scale excursions correlated with events in the high-resolution records of North Atlantic ice cores and European continental pollen sequences. The correlation of the mid-Eemian cooling about 122 kyr BP and the cold Montaigu event about 103 kyr BP with low production signals in the Baikal cores evidence for a climatic connection between the geographically distant North Atlantic, continental Europe, and continental Siberia regions. This connection was well pronounced during interglacials and interstadials and weak during the later glaciation. Rapid warm/cold transitions in the Baikal record, especially the Kazantsevo/Early Zyryanka transition, indicate that glaciation in Siberia began at 115-116 kyr BP, or 5-8 kyr earlier than in Europe and in the North Atlantic, as inferred from independent age models. The continuous climate record from Lake Baikal provides a solid stratigraphic background for detailed correlation of Siberian continental sections. Article 2003 English 00167886 Geologiya i Geofizika 44 623 – 637 7 Russian Federation; glacial-interglacial cycle; lacustrine deposit; paleoclimate; Quaternary; stratigraphic correlation https://www.scopus.com/inward/record.uri?eid=2-s2.0-0344441261&partnerID=40&md5=9d9dc2adec0bb05c70bfce3b0609165e Cited by: 3 A.A. Prokopenko E.B. Karabanov M.I. Kuz'min D.F. Williams G.K. Khursevich conference GerhardPratt2003 Time-lapse crosshole data were acquired at the Mallik Field, Northwest Territories (Canada) as a part of a large-scale research project into the production potential of arctic gas hydrates. Waveform tomography was used to form high-resolution quantitative images of the velocity and attenuation factors. The hydrate-bearing sediments are characterized by an expected increase in velocity, and an unusual increase in attenuation. The layers are predominantly 1-D, with subtle lateral changes in velocity and attenuation. © 2003 SEG Annual Meeting. All rights reserved. 2003 English 10523812 10.1190/1.1817798 2003 SEG Annual Meeting 22 Society of Exploration Geophysicists 2255-2258 Queen's University, Kingston, ON, Canada; GeoForschungsZentrum, Potsdam, Germany 1 Hydration; Petroleum prospecting; Tomography; Velocity, Attenuation factors; High resolution; Hydrate bearing sediments; Large-scale research; Quantitative images; Wave forms, Gas hydrates https://www.scopus.com/inward/record.uri?eid=2-s2.0-4644308110&partnerID=40&md5=704a2994a97fec085a13d2920477baa4 cited By 5 R. Gerhard Pratt K. Bauer M. Weber article Thurber200312 Arrival-time data from 453 local earthquakes and 6 explosions at Parkfield, CA, are inverted for earthquake locations and three-dimensional Vp and Vp/Vs structure. The structure is dominated by the velocity contrast across the SAF, with the southwest side about 20-25% faster, consistent with previous studies. Nearly all the earthquakes occur almost directly beneath the fault trace. We find high-Vp/Vs anomalies that correlate with low-resistivity features in a magnetotelluric model that are interpreted to represent fluids. We locate a magnitude 2 earthquake that is a potential target event for the final stage of SAFOD drilling, yielding a depth of 3.1 km below surface and an epicenter 100 m southwest of the fault trace. Nonlinear analyses indicate 95%-confidence relative and absolute uncertainties on the order of 500-700 m vertically and 200-300 m horizontally for this target earthquake. 2003 English 00948276 Geophysical Research Letters 30 12-1 University of Wisconsin-Madison, 1215 W. Dayton St., Madison, WI 53706, United States; Dept. of Earth/Environmental Sci., Rensselaer Polytechnic Institute, Troy, NY 12180, United States; Dept. of Geological Science, Brown University, Providence, RI 02912, United States 3 Data reduction; Drilling; Explosions; Geophysics, Arrival-time data, Earthquakes, earthquake epicenter; San Andreas Fault; seismicity; velocity structure, United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-0037998579&partnerID=40&md5=cd9f0b7f0f7a4d5a859dfc9b2bdf593f cited By 91 C. Thurber S. Roecker K. Roberts M. Gold L. Powell K. Rittger article Kontny2003 This study presents rock magnetic properties and the magnetic mineralogy of subaerial and submarine lava flows of Mauna Loa and Mauna Kea volcanoes collected from the 3109 m deep HSDP-2 drill hole in Hawaii. Three different groups of magnetic behavior are recognized in the subaerial lava flows related to the degree of high temperature oxidation during extrusion. Group 1 shows homogenous titanomagnetite with low Xmt, low Curie temperatures (TC: 100°-200°C) and weak median demagnetizing fields (&lt; 20 mT). Further subdivision into 1a and 1b subgroups is based on the low temperature behavior of magnetic susceptibility (MS) and hysteresis loops, which indicate a contribution from ferrimagnetic Cr-Al spinel below ca.-160°C in the 1b-type samples. Group 2 samples, with exsolution lamellae of ilmenite in the titanomagnetites, have higher TC (480°-580°C) and higher coercive forces (20-40 mT). Group 3, the highest oxidation stage, is characterized by titanohematite-bearing assemblages with enhanced median demagnetizing fields (35-85 mT) and a significantly different low-temperature MS behavior. MS core logging shows a systematic variation occurs in the subaerial lava flows, directly related to the degree of high temperature oxidation and their flow morphology. Aa lava flows have higher mean MS than other lava flow types. Besides these factors, MS appears to be also affected by the magma composition of the various shield-building stages. Mauna Loa subaerial lava flows generally show lower mean susceptibilities (4.6 ± 3 × 10-3 SI) than subaerial Mauna Kea lava flows (9.8 ± 5 × 10-3 SI). As submarine lava flows show no group 3 assemblages no high temperature oxidation influenced these rocks. Some hyaloclastites and pillow breccias show low MS (&lt; 1 × 10-3 SI), small amounts of nearly pure magnetite (TC = 580°C) and high coercive forces up to 110 mT suggesting single domain and/or superparamagnetic behavior. The controlling mechanism of the magnetic properties in the submarine lava units is the cooling and quenching rate of lava flows, which creates large grain size variations in titanomagnetites of varying compositions. Hydrothermal alteration, as described from ocean floor or Icelandic basalts, is not an important process that influences the magnetic properties in the ocean island basalts from the HSDP-2 drill hole. © 2003 by the American Geophysical Union. 2003 English 15252027 10.1029/2002GC000304 Geochemistry, Geophysics, Geosystems 4 Geologisch-Paläontologisches Institut, Ruprecht-Karls-Universität, Im Neuenheimer Feld 234, D-69120 Heidelberg, Germany; Institut für Geologie, Bayerische Julius-Maximilian Universität, Pleicherwall 1, D-97070 Würzburg, Germany 2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-1542368966&doi=10.1029%2f2002GC000304&partnerID=40&md5=c13b9e6c6bb52cd68847d3bc31caa98e cited By 37 A. Kontny C. Vahle H. De Wall article Lee200321 The project to determine the fault zone by San Andreas Fault Observatory at Depth (SAFOD) is discussed. The aim of the project is to drill straight into the heart of San Andreas Fault Zones and place sensors that will predict earthquake accurately. Engineers will be using SAFOD collected data to design roads and buildings to withstand the sort of earthquakes which they are going to expose. 2003 English 00137758 Engineer 292 21-24 7638 Earthquake faults, Drilling; Earthquakes; Investments; Project management; Seismology; Strategic planning, Seismic prospecting https://www.scopus.com/inward/record.uri?eid=2-s2.0-0242492783&partnerID=40&md5=6ddce663b4200b1e0d551ec1aeaf4628 cited By 0 A. Lee article Farrar2003305 Quaternary volcanic unrest has provided heat for episodic hydrothermal circulation in the Long Valley caldera, including the present-day hydrothermal system, which has been active over the past 40 kyr. The most recent period of crustal unrest in this region of east-central California began around 1980 and has included periods of intense seismicity and ground deformation. Uplift totaling more than 0.7 m has been centered on the caldera's resurgent dome, and is best modeled by a near-vertical ellipsoidal source centered at depths of 6-7 km. Modeling of both deformation and microgravity data now suggests that (1) there are two inflation sources beneath the caldera, a shallower source 7-10 km beneath the resurgent dome and a deeper source ∼15 km beneath the caldera's south moat and (2) the shallower source may contain components of magmatic brine and gas. The Long Valley Exploration Well (LVEW), completed in 1998 on the resurgent dome, penetrates to a depth of 3 km directly above this shallower source, but bottoms in a zone of 100°C fluid with zero vertical thermal gradient. Although these results preclude extrapolations of temperatures at depths below 3 km, other information obtained from flow tests and fluid sampling at this well indicates the presence of magmatic volatiles and fault-related permeability within the metamorphic basement rocks underlying the volcanic fill. In this paper, we present recently acquired data from LVEW and compare them with information from other drill holes and thermal springs in Long Valley to delineate the likely flow paths and fluid system properties under the resurgent dome. Additional information from mineralogical assemblages in core obtained from fracture zones in LVEW documents a previous period of more vigorous and energetic fluid circulation beneath the resurgent dome. Although this system apparently died off as a result of mineral deposition and cooling (and/or deepening) of magmatic heat sources, flow testing and tidal analyses of LVEW water level data show that relatively high permeability and strain sensitivity still exist in the steeply dipping principal fracture zone penetrated at a depth of 2.6 km. The hydraulic properties of this zone would allow a pressure change induced at distances of several kilometers below the well to be observable within a matter of days. This indicates that continuous fluid pressure monitoring in the well could provide direct evidence of future intrusions of magma or high-temperature fluids at depths of 5-7 km. © 2003 Elsevier B.V. All rights reserved. 2003 English 03770273 10.1016/S0377-0273(03)00174-4 Journal of Volcanology and Geothermal Research 127 Elsevier 305-328 U.S. Geological Survey, 5229 North Lake Blvd, Carnelian Bay, CA 96140, United States; U.S. Geological Survey, Vancouver, WA, United States; U.S. Geological Survey, Sacramento, CA, United States; Sandia National Laboratory, Albuquerque, NM, United States 3-4 Geochemistry; Metamorphic rocks; Mineral resources; Seismology, Hydrothermal circulation, Volcanoes, caldera; fluid flow; geochemistry; hydraulic property; hydrology; hydrothermal system; volcanism; well testing, California; Long Valley Caldera; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-0141974819&doi=10.1016%2fS0377-0273%2803%2900174-4&partnerID=40&md5=fd40ef322f4bdbcc79eb9dceb27da79f cited By 14 C.D. Farrar M.L. Sorey E. Roeloffs D.L. Galloway J.F. Howle R. Jacobson article Chan2003 [1] We determined lithium isotopic compositions of Mauna Loa and Mauna Kea basalts from the 3.1 km drill hole of the Hawaiian Scientific Drilling Project (HSDP); for comparison Li isotopic ratios were also determined for basalts from Koolau volcano. These two suites of samples define geochemical extremes in the range of Hawaiian shield lavas. The 400 Ka record of Mauna Kea in the HSDP core shows temporal fluctuations between low δ7Li (̃4% relative to the L-SVEC standard) and high δ7Li (5-6%), suggesting that the source components in the Hawaiian plume are heterogeneous in Li isotopic composition. Based on SiO2 content and isotopic ratios of He, Li, Nd, Hf and Pb, three geochemical groups are identified in Mauna Kea lavas. Mauna Kea basalts between 1900 and 2500 mbsl have relatively low δ7Li of about 4%. They are low SiO2 lavas distinguished by the highest 3He/4He and 208Pb/204Pb, and low 176Hf/ 177Hf and 143Nd/144Nd. Like basalt from Loihi seamount, this Mauna Kea group is considered to originate from the core of the plume. Above 1900 mbsl, high δ7Li lavas with high SiO 2 contents appear in both the submarine and subaerial sections. They are marked by low 3He/4He and high 176Hf/177Hf. The 7Li-rich signature of some samples (δ7Li up to 5.7) is indicative of recycled oceanic crust in the plume. This magma group defines the Kea component. The low SiO2 lavas in the subaerial section have low δ7Li (̃4%), 3He/4He and 208Pb/204Pb. Their δ7Li values overlap the range of δ7Li in unaltered mid-ocean ridge basalt (MORB) and are consistent with upper mantle material entrained by the plume or contamination of plume-derived magmas by the Pacific lithosphere. The δ7Li of Koolau lavas mostly fall within the range of 4.5 ± 0.3%. Exceptions are two samples that have δ7Li of 2-3%. The lightest isotopic values may indicate subducted Li that was isotopically fractionated during slab dehydration. In contrast to other isotopic systems, most Koolau samples, however, resemble Mauna Kea samples in Li isotopic composition. Mauna Loa samples have δ7Li values of 3.5 to 4.9%, within the range of the Koolau and Mauna Kea lavas. Based on these data, the Loa trend volcanoes and Kea trend volcanoes have largely overlapping Li isotopic compositions. In summary, the Hawaiian plume is not highly variable in Li isotopic composition; δ7Li is typically ̃4% with perturbations by subducted components to lower and higher ratios (2.5 to 5.7%). The overlap of most Hawaiian basalt and MORB in their range of Li isotopic ratios suggests minor influence of recycled oceanic crust in the plume and perhaps similar Li isotopic ratios in the upper and lower mantle. © 2003 by the American Geophysical Union. Article 2003 English 15252027 10.1029/2002GC000365 Geochemistry, Geophysics, Geosystems 4 Department of Geology and Geophysics, Louisiana State University, Baton Rouge, LA 70803, United States; Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, United States 3 https://www.scopus.com/inward/record.uri?eid=2-s2.0-1642526103&doi=10.1029%2f2002GC000365&partnerID=40&md5=e8e66c7dc745c76e93b2ee43d2a7126d cited By 118 L.-H. Chan F.A. Frey article Pribnow2003329 Temperatures of 100°C are measured at 3 km depth in a well located on the resurgent dome in the center of Long Valley Caldera, California, despite an assumed &gt;800°C magma chamber at 6-8 km depth. Local downflow of cold meteoric water as a process for cooling the resurgent dome is ruled out by a Peclét-number analysis of temperature logs. These analyses reveal zones with fluid circulation at the upper and lower boundaries of the Bishop Tuff, and an upflow zone in the metasedimentary rocks. Vertical Darcy velocities range from 10 to 70 cm a-1. A 21-km-long geoelectrical profile across the caldera provides resistivity values to the order of 100 to &gt;103 Ωm down to a depth of 6 km, as well as variations of self-potential. Interpretation of the electrical data with respect to hydrothermal fluid movement confirms that there is no downflow beneath the resurgent dome. To explain the unexpectedly low temperatures in the resurgent dome, we challenge the common view that the caldera as a whole is a regime of high temperatures and the resurgent dome is a local cold anomaly. Instead, we suggest that the caldera was cooled to normal thermal conditions by vigorous hydrothermal activity in the past, and that a present-day hot water flow system is responsible for local hot anomalies, such as Hot Creek and the area of the Casa Diablo geothermal power plant. The source of hot water has been associated with recent shallow intrusions into the West Moat. The focus of planning for future power plants should be to locate this present-day flow system instead of relying on heat from the old magma chamber. © 2003 Elsevier B.V. All rights reserved. 2003 English 03770273 10.1016/S0377-0273(03)00175-6 Journal of Volcanology and Geothermal Research 127 Elsevier 329-345 Inst.Geowiss.Gemeinschaftsaufgaben, Hannover, Germany; Universität Leipzig, Leipzig, Germany; GeoForschungsZentrum Potsdam, Potsdam, Germany; US Geological Survey, Flagstaff, AZ, United States 3-4 Cooling; High temperature effects; Sediment transport; Water, Magma chambers, Geothermal fields, caldera; electrical resistivity; fluid flow; geochemistry; hydrothermal fluid; thermal regime, California; Long Valley Caldera; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-0141959632&doi=10.1016%2fS0377-0273%2803%2900175-6&partnerID=40&md5=0e1803be06a8d4310e81ccc0baebc24c cited By 34 D.F.C. Pribnow C. Schütze S.J. Hurter C. Flechsig J.H. Sass article Fagel2003159 We investigated the mineralogical composition of two cores recovered on the Academician Ridge (Central Lake Baikal, Siberia). Sedimentological features show that the cores are unaffected by turbidity currents. However, hemipelagic deposition is not continuous, but intermittently disturbed by syn- or post-sediment reworking (e.g., bioturbation, slumps, faulting). Such modes of deposition are consistent with the complex uplift history of the ridge. Bulk mineralogy suggests that terrigenous sediment supplies are constant through glacial/interglacial stages, and diluted by diatom-rich intervals related to warmer interglacial stages. The core stratigraphy is based on the correlation of the diatom zonation and opal abundance with the marine oxygen isotope reference curve SPECMAP. The ∼8-m cores partly recover the last four interglacial/glacial cycles, i.e., since oxygen isotope stage 8. We test the use of clay minerals as a proxy for paleoclimatic reconstruction. The clays are more weathered during the diatom-rich intervals in agreement with warmer climate conditions. However, the mean clay composition does not change significantly through glacial/interglacial stages. This observation implies that, in the Academician Ridge sediments, a simple smectite/illite ratio (S/I) does not alone provide a reliable indicator of climatic variation. It reflects the complex clay assemblages, especially the smectite group, delivered to Central Lake Baikal. Smectites include primarily illite-smectite mixed layers, made of a mixture of montmorillonite and beidellite. According to their behavior after cation saturation, the illite-smectite mixed layers are primarily transformed smectites, with some neoformed smectites intermittently observed. In addition, Al-smectites occur in minor proportions. We conclude that the S/I ratio has a climatic significance only if it evolves in parallel with the weathering stage of the clays and is confirmed by a change in the composition of the smectites. © 2002 Elsevier Science B.V. All rights reserved. Article 2003 English 00310182 10.1016/S0031-0182(02)00633-8 Palaeogeography, Palaeoclimatology, Palaeoecology 193 159 – 179 1 Russian Federation; Bacillariophyta; clay mineral; illite; lacustrine deposit; paleoclimate; proxy climate record; Quaternary; smectite https://www.scopus.com/inward/record.uri?eid=2-s2.0-0037378226&doi=10.1016%2fS0031-0182%2802%2900633-8&partnerID=40&md5=3ed9cdab5a306023bd8d42c1cb90dc9c Cited by: 74; All Open Access, Green Open Access N. Fagel T. Boski L. Likhoshway H. Oberhaensli article Dressler2003 2003 10.1029/2003EO140001 Eos 84 125+130 Lunar and Planetary Institute, Houston, United States 14 https://www.scopus.com/inward/record.uri?eid=2-s2.0-53549085726&doi=10.1029%2f2003EO140001&partnerID=40&md5=6088a69949b7cdf9b0581d443f2ef8d8 cited By 64 B.O. Dressler V.L. Sharpton J. Morgan R. Buffler D. Moran J. Smit D. Stäffler J. Urrutia article Rowe2003273 We present and compare AMS-14C geochronologies for sediment cores recovered from Lake Titicaca, South America. Radiocarbon dates from three core sites constrain the timing of late Quaternary paleoenvironmental changes in the Central Andes and highlight the site-specific factors that limit the radiocarbon geochronometer. With the exception of mid-Holocene sediments, all cores are generally devoid of macrophyte fragments, thus bulk organic fractions are used to build core chronologies. Comparisons of radiocarbon results for chemically defined fractions (bulk decalcified, humate, humin) suggest that ages derived from all fractions are generally coherent in the post-13,500 yr BP time interval. In the pre-13,500 yr BP time interval, ages derived from humate extracts are significantly younger (300-7000 years) than ages from paired humin residues. Gross age incoherencies between paired humate and humin sub-fractions in pre-13,500 yr BP sediments from all core sites probably reflect the net downward migration of humates. Ages derived from bulk decalcified fractions at our shallow water (90 m) and deep water (230 m) core sites consistently fall between ages derived from humate and humin sub-fractions in the pre-13,500 yr BP interval, reflecting that the bulk decalcified fraction is predominantly a mixture of humate and humin sub-fractions. Bulk decalcified ages from the pre-13,500 yr BP interval at our intermediate depth core site (150 m) are consistently older than humate (youngest) and humin sub-fractions. This uniform, reproducible pattern can be explained by the mobilization of a relatively older organic sub-fraction during and after the re-acidification step following the alkaline treatment of the bulk sediment. The inferred existence of this 'alkali-mobile, acid-soluble' sub-fraction implies a different depositional/post-depositional history that is potentially associated with a difference in source material. While internally consistent geochronologies can be developed for the Lake Titicaca sequence using different organic fractions, mobile organic sub-fractions and fractions containing mobile sub-fractions should generally be avoided in geochronology studies. Consequently, we believe humin and/or bulk decalcified ages provide the most consistent chronologies for the post-13,500 yr BP interval, and humin ages provide the most representative ages for sedimentation prior to 13,500 yr BP interval. Using the age model derived from the deep water core site and a previously published isotope-based lake-level reconstruction, we present a qualitative record of lake level in the context of several ice-core records from the western hemisphere. We find the latest Pleistocene lake-level response to changing insolation began during or just prior to the Bølling/Allerød period. Using the isotope-based lake-level reconstruction, we also find the 85-m drop in lake level that occurred during the mid-Holocene was synchronous with an increase in the variability of ice-core δ18O from a nearby icecap, but was not reflected in any of the polar ice-core records recovered from the interior of Antarctica and Greenland. © 2003 Published by Elsevier B.V. Article 2003 10.1016/S0921-8181(03)00031-6 Global and Planetary Change 38 273 – 290 3-4 Lake Titicaca; South America; geochronology; lake level; paleolimnology; radiocarbon dating; sediment core; stable isotope https://www.scopus.com/inward/record.uri?eid=2-s2.0-0141677771&doi=10.1016%2fS0921-8181%2803%2900031-6&partnerID=40&md5=b7b44c2aff7e67d5d08a3a9791a2c6db Cited by: 41; All Open Access, Green Open Access Harold D. Rowe Thomas P. Guilderson Robert B. Dunbar John R. Southon Geoffrey O. Seltzer David A. Mucciarone Sherilyn C. Fritz Paul A. Baker article Karabanov2003223 Book chapter 2003 10.1029/137GM16 Geophysical Monograph Series 137 223 – 230 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84962185511&doi=10.1029%2f137GM16&partnerID=40&md5=40be30bb68df488cf14fcd1bf40136d9 Cited by: 12 Eugene B. Karabanov Alexander A. Prokopenko Douglas F. Williams Galina K. Khursevich Mikhail I. Kuzmin Elena V. Bezrukova Alexander N. Gvozdkov article Katz2003 Hawaiian lava flows are classified as pahoehoe or ̀àa by their surface morphology. As surface morphology reflects flow emplacement conditions, the surface distribution of morphologic flow types has been used to study the evolution and eruptive history of basaltic volcanoes. We extend this analysis to the third dimension by determining the distribution of flow types in two deep drill cores, the Scientific Observation Hole-4 (SOH-4) core, drilled near Kilauea's East Rift Zone (ERZ), and the pilot hole (Kahi Puka-1 (KP-1)) for the Hawaiian Scientific Drilling Project (HSDP), drilled through distal flows from Mauna Loa and Mauna Kea. Flows are classified using both internal structures and groundmass textures, with the latter useful when identification based on mesoscopic flow features (e.g., surface morphology and vesicle content and distribution) is ambiguous. We then examine the temporal distribution of pahoehoe and ̀àa flows in proximal (SOH-4) and distal (KP-1) settings. Sequence analysis shows that the two flow types are not randomly distributed in either core but instead are strongly clustered. The proximal SOH-4 core is dominated by thin pahoehoe flows (̃60% by volume), consistent with the common occurrence of surface-fed pahoehoe flows in near-vent settings. The distal KP-1 core has a high proportion of ̀àa (̃58% by volume), although the proportion of pahoehoe and̀àa varies dramatically throughout the Mauna Kea sequence. Thick inflated pahoehoe flows dominate when the drill site was near sea level, consistent with the numerous inflated pahoehoe fields on the current coastal plains of Kilauea and Mauna Loa. ̀Àa flows are abundant when the site was far above sea level. As slope increases from the coastal plains to Mauna Kea's flank, this correlation may reflect the combined effect of long transport distances and increased slopes on flow emplacement. These results demonstrate that flow type and thickness variations in cores provide valuable information about both vent location and local site environment. Observed variations in flow type within the KP-1 core raise interesting questions about feedback between volcano evolution and flow morphology and suggest that flow type is an important variable in models of volcano growth and related models for lava flow hazard assessment. © 2003 by the American Geophysical Union. 2003 English 15252027 10.1029/2001GC000209 Geochemistry, Geophysics, Geosystems 4 Department of Geological Sciences, University of Oregon, Eugene, OR, 97403-1272, United States 2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-67349099488&doi=10.1029%2f2001GC000209&partnerID=40&md5=4727a773743e2110f03c87bd688a6997 cited By 40 M.G. Katz K.V. Cashman article Janne2003 The present work reports multiple collector inductively coupled plasma mass spectrometry (MC-ICPMS) measurements of the isotopic compositions of Hf and Pb in the first 3 km of the deep core retrieved by the Hawaii Scientific Drilling Project. The measurements cover all the samples from the standard geochemical reference set, glasses from the deep hole, and replicates from the pilot hole. Both Hf and Pb are less radiogenic in Mauna Loa compared to Mauna Kea. The transition between Mauna Kea and Mauna Loa lavas in the deep core is progressive for eHf and 208Pb/204Pb, but a sharp discontinuity is observed for 208Pb*/206Pb*. There is no correlation between the alkalinity of the samples and isotopic composition. In detail, the Hf isotope compositions of samples from the pilot hole are not all identical to those of the HSDP-2 core for samples retrieved from a similar depth, suggesting that steep topography existed at the time of emplacement or that a different eruptive sequence was recorded. The strong correlation between 208Pb*/206Pb* and 3He/ 4He (He data from M. D. Kurz et al. (Rapid helium isotopic variability in Mauna Kea shield lavas from the Hawaiian Scientific Drilling Project, submitted to Geochemistry Geophysics Geosystems, 2002)) requires the episodic incorporation of a component that resembles the basalts erupted by either Kilauea or the Loihi eruptive centers (this component is referred to as K/L). The data suggest that some 500 kyr ago, Mauna Kea was tapping a mantle source similar to that tapped by Kilauea today. Isotopic variability of Pb and He cannot be accounted for by radiogenic ingrowth in a closed system, but requires the mixing of mantle source components with distinct outgassing histories. The time series of isotopic and concentration data in Mauna Kea samples spanning about 350,000 years of age indicate the recurrence of geochemical patterns in the melting column. Ignoring the most recent alkalic samples, we find that the dominant fluctuations of eHf and 207Pb/204Pb correspond to a period of 50,000 years. For La/ Yb, Zr/Nb, 87Sr/ 86Sr, 206Pb/204Pb, 207Pb/ 206Pb, and 208Pb/206Pb, a dominant period of ca. 18,000 years is obtained. Once provision is made for the existence of harmonics, the consistency between the isotopic spectrum of the pilot hole and the HDSP-2 core is very good. The input of the K/L component does not seem to be periodic. We use these recurrence intervals in conjunction with the upwelling rate deduced from buoyancy flux and seismic evidence of the maximum dimension of scatterers to constrain the radius of the Hawaiian plume conduit to be in the range of 10-50 km and the upwelling velocity to be in the range of 0.13-3 m/yr. Plausible vertical length scales of heterogeneities in the conduit are 6.5-160 km. © 2003 by the American Geophysical Union. Article 2003 English 15252027 10.1029/2002GC000340 Geochemistry, Geophysics, Geosystems 4 2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-72749086414&doi=10.1029%2f2002GC000340&partnerID=40&md5=bde6696dc5ee8ae5050729f1f1b18d54 Cited by: 132; All Open Access, Bronze Open Access Blichert-Toft Janne Dominique Weis Claude Maerschalk Arnaud Agranier Francis Albarède article Boamah20031137 The 1.07 Ma well-preserved Bosumtwi impact structure in Ghana (10.5 km in diameter) formed in 2 Ga-old metamorphosed and crystalline rocks of the Birimian system. The interior of the structure is largely filled by the 8 km diameter Lake Bosumtwi, and the crater rim and region in the environs of the crater is covered by tropical rainforest, making geological studies rather difficult and restricted to road cuts and streams. In early 1999, we undertook a shallow drilling program to the north of the crater rim to determine the extent of the ejecta blanket around the crater and to obtain subsurface core samples for mineralogical, petrological, and geochemical studies of ejecta of the Bosumtwi impact structure. A variety of impactite lithologies are present, consisting of impact glass-rich suevite and several types of breccia: lithic breccia of single rock type, often grading into unbrecciated rock, with the rocks being shattered more or less in situ without much relative displacement (autochthonous?), and lithic polymict breccia that apparently do not contain any glassy material (allochtonous?). The suevite cores show that melt inclusions are present throughout the whole length of the cores in the form of vesicular glasses with no significant change of abundance with depth. Twenty samples from the 7 drill cores and 4 samples from recent road cuts in the structure were studied for their geochemical characteristics to accumulate a database for impact lithologies and their erosion products present at the Bosumtwi crater. Major and trace element analyses yielded compositions similar to those of the target rocks in the area (graywacke-phyllite, shale, and granite). Graywacke-phyllite and granite dikes seem to be important contributors to the compositions of the suevite and the road cut samples (fragmentary matrix), with a minor contribution of Pepiakese granite. The results also provide information about the thickness of the fallout suevite in the northern part of the Bosumtwi structure, which was determined to be ≤15 m and to occupy an area of ∼1.5 km2. Present suevite distribution is likely to be caused by differential erosion and does not reflect the initial areal extent of the continuous Bosumtwi ejecta deposits. Our studies allow a comparison with the extent of the suevite at the Ries, another well-preserved impact structure. Article 2003 English 10869379 10.1111/j.1945-5100.2003.tb00304.x Meteoritics and Planetary Science 38 University of Arkansas 1137 – 1159 8 Bosumtwi Impact Structure; Ghana; breccia; ejecta; geochemistry; geological structure; impact structure; tektite https://www.scopus.com/inward/record.uri?eid=2-s2.0-0346963758&doi=10.1111%2fj.1945-5100.2003.tb00304.x&partnerID=40&md5=b2feacda66e69800674021b5a82a8302 Cited by: 31 Daniel Boamah Christian Koeberl article Oberhänsli2002699 Delicate primary volcanic features such as ash layers, volcaniclastic breccias, and pillow lavas with amygdaloidal rims have been identified in a terrigenous volcanosedimentary sequence forming part of the ultrahigh-pressure unit of the Dabie Shan, China. The presence of coesite relies in crosscutting dikes confirms an ultrahigh-pressure evolution for the entire sequence. Evaluation of the probable reaction history for zeolite compositions as supposed for the amygdaloidal rims reveals a scarcity of reactions at very high pressures. Such special conditions of low reactivity and fluid- conserving reactions, combined with a lack of directed stress, have allowed the remarkable preservation of these primary volcanic features despite deep subduction. Article 2002 English 00917613 10.1130/0091-7613(2002)030<0699:POPVTI>2.0.CO;2 Geology 30 699 – 702 8 China; High pressure effects; Levees; Zeolites; Pillow lava; pillow lava; preservation; ultrahigh pressure metamorphism; volcanic feature; volcaniclastic deposit; Volcanoes https://www.scopus.com/inward/record.uri?eid=2-s2.0-0036694242&doi=10.1130%2f0091-7613%282002%29030%3c0699%3aPOPVTI%3e2.0.CO%3b2&partnerID=40&md5=c12c262f3027699163e3d7af15672fe9 Cited by: 41 R. Oberhänsli G. Martinotti R. Schmid X. Liu article Moretti200291 In their aim to understand the hydraulic behaviour of faults and fractures, and their changes with stress variation, geoscientists are still poorly armed. On the one hand, data indicate that the rheology of faulted strata plays a major role: shale may create clay smearing (Lehner & Pilaar 1997), whereas, at temperatures over 80/100 °C, pressure solution processes quickly seal fractures in sandstones after rupture (Morentti et al. 2000; Labaume & Moretti 2001). The hydraulic behaviour of discontinuities also appears to be stress-dependent (Sibson 1994), and may therefore change during the depletion of oil and gas fields. We are still unable to quantify these changes and indicate eventualthresholds. On the other hand, fluid pressureinfluences the friction on the fault planes, and therefore changes the rate of displacement. A large number of seismologists consider that the low average friction coefficient in large fault zones is due to high fluid pressure (Evans 1992 and many others). The permanent and instantaneous hydraulic behaviour of faults and fractures under a stress/strain regime obviously differs due to diagenetic processes, but the rate of the fluid/rock interactions which could be related to the build up of high pressures in the faults themselvesis still a subject of debate. In order to clarify these issued, a complete dataset is necessary. European academicand private laboratories (as well as someoil companies) have decided to pool their efforts to collect such a dataset by creating the Corinth Rift Laboratory (CRL), with the help of the EC. The goal is to investigate fault mechanics and their relation to fluid flow and earthquakes by continuous monitoring of strain, seismicity, fluid pressure and geochemistry - at the surface and at various depths in boreholes intersecting active faults. Due to the volume of data collected and the necessity of disctributing these data to various centres, research in data management is also being carried out. Around the world, two other ambitious projects have been set up with the same goals but in different geological contexts: one to monitor the San Andreas fault, which is a strike-slip fault outcropping in granite, and a second to drill the subduction zone in Japan. In our case, we will drill extensional faults through sedimentary rocks; mainly limestones. Article 2002 English 02635046 10.1046/j.1365-2397.2002.00242.x First Break 20 91 – 97 2 active fault; hydraulic property; pressure solution; rheology; stress change https://www.scopus.com/inward/record.uri?eid=2-s2.0-0036173570&doi=10.1046%2fj.1365-2397.2002.00242.x&partnerID=40&md5=e6de1e1628ad16d86fd63d4374ec0fc0 Cited by: 17 I. Moretti J.P. Delhomme F. Cornet P. Bernard C. Schmidt-Hattenberger G. Borm conference Saito2002633 The International Scientific Drilling Project to drill into the recently erupted magma conduit was initiated in 1999, at the Unzen Volcano, Japan. Since then, two flank core holes and a pilot hole, with a total length of 2.5 km, were drilled successfully. Borehole temperatures were measured using existing Sandia CTDL (Core Tube Data Logger) while coring. The conduit hole, with a very high angle and with about a 1700m-drilled length, is planned to be drilled beginning in January 2003. To identify conduit position and to assure drilling safety, temperature measurements are planned during conduit drilling operations. New memory tools, with 250 °C temperature rating, and possibly 500 °C with MR dewar, are planned to be designed and fabricated to satisfy the project requirements. 2002 English 01935933 Transactions - Geothermal Resources Council 633-637 Boreholes; Project management; Underground temperature measurement; Volcanoes, Memory tools, Rock drilling https://www.scopus.com/inward/record.uri?eid=2-s2.0-0242409780&partnerID=40&md5=cbcd5d237bd7458dbb01854417b0be1a cited By 1 S. Saito J. Henfling article Huang2002253 Stratigraphy, sedimentary facies, and deformation characteristics of drill cores from Fengyuan and Noutou wells reveal important attributes for the westmost portion of active Chelungpu thrust fault and contrasting deformation mechanisms between the north and south ends. Stratigraphy of the Fengyuan well (including BH-1 and BH-1A boreholes) is composed of three major units, including the upper Miocene to Pliocene Kueichulin Formation (455.4-224.7 m), the Pliocene Chinshui Shale (224.7-3.9 m) and recent terrace deposits (3.9-0 m). The Kueichulin Formation comprises three upward coarsening, tide-dominated delta parasequences with sandstone and sandstone-Shale alternations. The Chinshui Shale is dominated by shallow marine facies with siltstone, mudstone and fine-grained sandstone. Shallow marine facies are occasionally intercalated with tide-dominated delta deposits. Terrace deposits are characterized by paleosol, yellowish mud, mottled leaching soil and thin pebble layers. The Chi-Chi earthquake slip zone is located at a transgressive deposit, which is also the sequence boundary between the Kueichulin Formation and the Chinshui Shale. Other two major brecciated shear zones are also the parasequence boundaries within the Kueichulin Formation. Stratigraphic sequence of the Nantou well (CLF-2) is composed of the Pleistocene Toukoshan Formation (211.9-177 m) in the footwall, and the Chinshui Shale (177-8.7 m) and terrace deposits (8.7-0 m) in the hangingwall. The Toukoshan Formation is characterized by alternation of conglomerates and yellowish fine-grained deposits with drifted pebbles, an indication of braided fluvial deposits. The Chinshui Shale comprises alternating shallow marine and tidal deposits. The shallow marine face is dominated by mudstone, siltstone and fine-grained sandstone with moderate to high degree of bioturbation. Terrace deposits are characterized by yellowish gray mud, pebble layer, and mottled paleosol. Overall, shear zones in the Nantou well is characterized by foliated gouge or breccia as opposed to breccia or gouge of random fabrics in the Fengyuan well. 2002 English 10170839 10.3319/TAO.2002.13.3.253(CCE) Terrestrial, Atmospheric and Oceanic Sciences 13 Chinese Geoscience Union 253-278 Exploration/Development Res. Inst., Chinese Petroleum Corporation, 1 Ta Yuan, Wen Shan, Miaoli 36010, Taiwan 3 Chi-Chi earthquake 1999; deformation; fault zone; sequence stratigraphy; Tertiary; thrust fault, (Central); Taiwan https://www.scopus.com/inward/record.uri?eid=2-s2.0-0036752985&doi=10.3319%2fTAO.2002.13.3.253%28CCE%29&partnerID=40&md5=01f1bd497ede3f94a5d3d87811875ef3 cited By 19 S.-T. Huang J.-C. Wu J.-H. Hung H. Tanaka article Wang2002211 Several seismic reflection surveys were conducted to investigate the seismogenic structure of the 1999 Chi-Chi earthquake (Mw=7.6) in central Taiwan. Two 40 km-long seismic profiles that crossed the area near the epicenter were acquired using the deep reflection method with a targeting depth of 10 km, to search for the decollement boundary. One of the obtained sections shows a clear reflection event that dips to the east by 40° until reaching a depth of 8 km where the earthquake's source was located. This slant event is unambiguously related to the thrusting Chelungpu fault surface. The abundant eastward dipping reflectors on the deep reflection sections faithfully describe thrusting features predicted by the earthquake faulting model. Besides these deep reflections, we also used many shallow seismic reflection lines to delineate the structures in the northern portion of the fault zone, where large ruptures (about 10 m) occurred both on the surface and underground. The 3D structure of the fault surface can be deduced using this cost-effective approach. Although the depth imaged may be limited (e.g., 3 km), shallow seismic data still provides reliable information for the study of large ruptures, and to make better plans for deep wells that might be drilled in this area in the future. 2002 English 10170839 10.3319/TAO.2002.13.3.211(CCE) Terrestrial, Atmospheric and Oceanic Sciences 13 Chinese Geoscience Union 211-226 Institute of Geophysics, National Central University, Chung-Li, Taiwan 3 Chi-Chi earthquake 1999; fault; geological mapping; seismic reflection, (Central); Taiwan https://www.scopus.com/inward/record.uri?eid=2-s2.0-0036752541&doi=10.3319%2fTAO.2002.13.3.211%28CCE%29&partnerID=40&md5=2bc9ee63fbe21b99d604f7bedeb4ceae cited By 39 C.-Y. Wang C.-L. Li F.-C. Su M.-T. Leu M.-S. Wu S.-H. Lai C.-C. Chern article Guerin2002 The Mallik 2L-38 research well was drilled to 1150 m under the Mackenzie Delta, Canada, and penetrated a subpermafrost interval where methane hydrate occupies up to 80% of the pore space. A suite of high-quality downhole logs was acquired to measure in situ the physical properties of these hydrate-bearing sediments. Similar to other hydrate deposits, resistivity and compressional and shear sonic velocity data increase with higher hydrate saturation owing to electrical insulation of the pore space and stiffening of the sediment framework. In addition, sonic waveforms show strong amplitude losses of both compressional and shear waves in intervals where methane hydrate is observed. We use monopole and dipole waveforms to estimate compressional and shear attenuation. Comparing with hydrate saturation values derived from the resistivity log, we observe a linear increase in both attenuation measurements with increasing hydrate saturation, which is not intuitive for stiffening sediments. Numerical modeling of the waveforms allows us to reproduce the recorded waveforms and illustrate these results. We also use a model for wave propagation in frozen porous media to explain qualitatively the loss of sonic waveform amplitude in hydrate-bearing sediments. We suggest that this model can be improved and extended, allowing hydrate saturation to be quantified from attenuation measurements in similar environments and providing new insight into how hydrate and its sediment host interact. 2002 English 21699313 Journal of Geophysical Research: Solid Earth 107 Blackwell Publishing Ltd EPM 1-1 - EPM 1-12 Borehole Research Group, Lamont-Doherty Earth Observatory, Palisades, NY, United States 5 acoustic logging; gas hydrate; porous medium; wave propagation; well logging, Canada; Mackenzie Delta https://www.scopus.com/inward/record.uri?eid=2-s2.0-0037053547&partnerID=40&md5=48987f68a276606dd2157237245ba706 cited By 139 G. Guerin D. Goldberg article Wang2002153 Two shallow holes (∼300m) were drilled to uncover cores to study the properties of the Chelungpu fault, which was activated during the 1999 Chi-Chi earthquake (Mw=7.6), Taiwan. Before drilling, we collected seismic reflection data near the wells to aid the drilling processes. The depths predicted by the seismic reflection sections proved to be very close to the drilling results. These seismic sections also provided details of underground 2D structures, which are of help in clarifying the relationship of the well with the neighboring geology. Besides this, we also present several seismic sections describing the undisturbed structures on the Chelungpu fault's footwall side opposite the violated hanging-wall side. A detachment type of movement is suggested to explain this extraordinary phenomenon. Finally, a combination of seismic and electric methods was implemented to explore the near-surface structure of the Sanyi fault, which is believed to be the counterpart of the Chelungpu fault but at a deeper location. The results show that the Sanyi fault is old and has ceased its movement, perhaps not having been involved in the Chi-Chi earthquake's action. 2002 English 10170839 10.3319/TAO.2002.13.2.153(T) Terrestrial, Atmospheric and Oceanic Sciences 13 Chinese Geoscience Union 153-170 Institute of Geophysics, National Central University, Chung-Li, Taiwan, Taiwan 2 drilling; earthquake; fault; seismic reflection, Chichi; Taiwan https://www.scopus.com/inward/record.uri?eid=2-s2.0-0036019693&doi=10.3319%2fTAO.2002.13.2.153%28T%29&partnerID=40&md5=906773ecca389dc380e90e5bc5335545 cited By 14 C.-Y. Wang H. Tanaka J. Chow C.-C. Chen J.-H. Hong article Karp2002735 The Lake Bosumtwi impact crater in Ghana, West Africa, has a diameter of 10.5 km and is one of the youngest (1.07 Ma) well-preserved large craters on Earth. It has a total dynamic range of topography of more than 400 m, and it is the source crater of tektites and microtektites of the Ivory Coast strewn field. The crater was excavated in early Proterozoic rocks. According to its size, the Bosumtwi impact crater should be a complex impact structure, with a central peak. Multichannel seismic (MCS) reflection and wide angle data, using Ocean-Bottom-Hydrophones (OBHs), were acquired in order to investigate the structure's subsurface, image the presumed central uplift and determine the thickness of impact-related formations and the post-impact sediments. An integrated interpretation of the seismic data sets, and modelling and inversion of the OBH data yield an initial 2D velocity-depth model, which shows indications for a central peak feature. Due to the relatively low seismic velocity (3.0 kms-1) of the corresponding layer, the top of the uplifted structure is interpreted to consist of allochthonous breccia. The central peak has a width of ∼1.8 km and a maximum height of 120 m above the top of the breccia away from the center. Fracturing may be responsible for the relatively low velocity of 3.8 kms-1 in the crater floor. The post-impact sediments covering the crater structure are 180-300 m thick. The apparent crater depth, defined as the difference between the original target surface and the top of the breccia layer, is ∼550 m and thereby slightly deeper than some other larger complex impact structures on Earth. The results indicate that the Lake Bosumtwi impact structure provides an interesting setting for scientific drilling of a young large impact crater and will be supplemented by complimentary recent geophysical (potential field) and possibly future drilling studies. © 2002 Elsevier Science Ltd. All rights reserved. Article 2002 English 00320633 10.1016/S0032-0633(02)00049-1 Planetary and Space Science 50 735 – 743 7-8 Drilling; Earth (planet); Geophysics; Hydrophones; Rocks; Topography; Seismic prospecting https://www.scopus.com/inward/record.uri?eid=2-s2.0-0036621801&doi=10.1016%2fS0032-0633%2802%2900049-1&partnerID=40&md5=668ad55a8144f89c4bceb93f3b01d75e Cited by: 40 Tobias Karp Bernd Milkereit Peter Janle Sylvester K. Danuor Jean Pohl Hans Berckhemer Christopher A. Scholz article Harris200234 Researchers from universities around the country and from the United States Geological Survey (USGS), headquartered in Reston, Virginia, are planning to dig a pilot hole inside California's San Andreas Fault with hopes of eventually developing a larger, adjacent hole that will serve as an earthquake observatory. The observatory, to be called the San Andreas Fault Observatory at Depth (SAFOD), will be designed to determine the physical and chemical processes at work in an active fault zone. 2002 English 08857024 Civil Engineering 72 34-35 7 Earthquakes; Geological surveys; Observatories, Earthquake observatory, Civil engineering, active fault; borehole; earthquake; observatory, United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-0036647072&partnerID=40&md5=d97f323dfdf13ac5ebd790097132438f cited By 0 C.A. Harris article Jin2002407 Well logs acquired at the Mallik 2L-38 gas hydrate research well. Mackenzie Delta, Canada, reveal a distinct trend showing that the resistivity of gas-hydrate-bearing sediments increases with increases in density porosities. This trend, opposite to the general trend of decrease in resistivity with porosity, implies that gas hydrates are more concentrated in the higher porosity. Using the Mallik 2L-38 well data, a proportional gas hydrate concentration (PGHC) model, which states that the gas hydrate concentration in the sediment's pore space is linearly proportional to porosity, is proposed for the general habitat of gas hydrate in sediments. Anomalous data (less than 6% of the total data) outside the dominant observed trend can be explained by local geological characteristics. The anomalous data analysis indicates that highly concentrated gas-hydrate-bearing layers would be expected where sediments have high proportions of gravel and coarse sand. Using the parameters in the PGHC model determined from resistivity-porosity logs, it is possible to qualitatively predict the degree of reflection amplitude variations in seismic profiles. Moderate-to-strong reflections are expected for the Mallik 2L-38 well. © 2002 Elsevier Science Ltd. All rights reserved. 2002 English 02648172 10.1016/S0264-8172(02)00011-9 Marine and Petroleum Geology 19 407-415 Korea Ocean Research, Development Institute, Ansan P.O. Box 29, Seoul 425-600, South Korea; US Geological Survey, Denver Federal Center, Box 25046, Denver, CO 80225, United States 4 Pore spaces, Gas hydrates; Porosity; Reflection; Sand; Sediments; Seismic prospecting; Well logging, Geology, amplitude; gas hydrate; porosity; seismic data; seismic reflection; well logging, Canada https://www.scopus.com/inward/record.uri?eid=2-s2.0-0036544514&doi=10.1016%2fS0264-8172%2802%2900011-9&partnerID=40&md5=e8c857b0d3d1c9914fe3d7dc6a763056 cited By 14 Y.K. Jin M.W. Lee T.S. Collett article Hurwitz2002ECV13 Temperature measurements in deep drill holes on volcano summits or upper flanks allow a quantitative analysis of groundwater induced heat transport within the edifice. We present a new temperature-depth profile from a deep well on the summit of Kilauea Volcano, Hawaii, and analyze it in conjunction with a temperature profile measured 26 years earlier. We propose two groundwater flow models to interpret the complex temperature profiles. The first is a modified confined lateral flow model (CLFM) with a continuous flux of hydrothermal fluid. In the second, transient flow model (TFM), slow conductive cooling follows a brief, advective heating event. We carry out numerical simulations to examine the timescales associated with each of the models. Results for both models are sensitive to the initial conditions, and with realistic initial conditions it takes between 750 and 1000 simulation years for either model to match the measured temperature profiles. With somewhat hotter initial conditions, results are consistent with onset of a hydrothermal plume ∼550 years ago, coincident with initiation of caldera subsidence. We show that the TFM is consistent with other data from hydrothermal systems and laboratory experiments and perhaps is more appropriate for this highly dynamic environment. The TFM implies that volcano-hydrothermal systems may be dominated by episodic events and that thermal perturbations may persist for several thousand years after hydrothermal flow has ceased. Article 2002 English 21699313 Journal of Geophysical Research: Solid Earth 107 Blackwell Publishing Ltd ECV 13–1 – 13–10 11 Hawaii; Kilauea Volcano; United States; groundwater flow; heat transfer; hydrothermal system; perturbation; transient flow; volcano; well https://www.scopus.com/inward/record.uri?eid=2-s2.0-0037542515&partnerID=40&md5=09e9685874ef9b1c8ed90cd737dc63cd Cited by: 27 Shaul Hurwitz Steven E. Ingebritsen Michael L. Sorey article shervais2002origin 2002 Tectonic and Magmatic Evolution of the Snake River Plain Volcanic Province 30 Idaho Geologic Survey Bulletin Moscow, Idaho USA 343--361 John W Shervais Gaurav Shroff Scott K Vetter Scott Matthews Barry B Hanan James J McGee B Bonnichsen CM White M McCurry article Dallimore2002 2002 English 00963941 10.1029/2002EO000129 Eos 83 American Geophysical Union 193+198 Geological Survey of Canada, Ottawa, Canada; U.S. Geological Survey, Denver, CO, United States; GeoForschungs Zentrum, Potsdam, Germany; Japan National Oil Corporation, Chiba, Japan 18 https://www.scopus.com/inward/record.uri?eid=2-s2.0-30144442960&doi=10.1029%2f2002EO000129&partnerID=40&md5=d519b792f5d766d246d0843fb5c14057 cited By 7 S.R. Dallimore T.S. Collett M. Weber T. Uchida article Lee20021711 Elevated elastic velocities are a distinct physical property of gas hydrate-bearing sediments. A number of velocity models and equations (e.g., pore-filling model, cementation model, effective medium theories, weighted equations, and time-average equations) have been used to describe this effect. In particular, the weighted equation and effective medium theory predict reasonably well the elastic properties of unconsolidated gas hydrate-bearing sediments. A weakness of the weighted equation is its use of the empirical relationship of the time-average equation as one element of the equation. One drawback of the effective medium theory is its prediction of unreasonably higher shear-wave velocity at high porosities, so that the predicted velocity ratio does not agree well with the observed velocity ratio. To overcome these weaknesses, a method is proposed, based on Biot-Gassmann theories and assuming the formation velocity ratio (shear to compressional velocity) of an unconsolidated sediment is related to the velocity ratio of the matrix material of the formation and its porosity. Using the Biot coefficient calculated from either the weighted equation or from the effective medium theory, the proposed method accurately predicts the elastic properties of unconsolidated sediments with or without gas hydrate concentration. This method was applied to the observed velocities at the Mallik 2L-39 well, Mackenzie Delta, Canada. 2002 English 00168033 10.1190/1.1527072 Geophysics 67 Society of Exploration Geophysicists 1711-1719 U.S. Geological Survey, Denver Federal Center, Denver, CO 80225, United States 6 Concentration (process); Elasticity; Hydrates; Porosity; Sediments; Acoustic wave velocity; Gas hydrates; Gases; Hydration; Seismic waves; Seismology; Shear waves; Wave propagation, Elastic velocities; Compressional velocities; Effective medium theories; Empirical relationships; Gas hydrate bearing sediments; Gas hydrate concentrations; Shear wave velocity; Solid structures; Unconsolidated sediment, Geophysics; Shear flow, Biot theory; elastic wave; gas hydrate; P-wave; S-wave; velocity https://www.scopus.com/inward/record.uri?eid=2-s2.0-0036867532&doi=10.1190%2f1.1527072&partnerID=40&md5=de885bdfbf6b73789e1cd69d7511f554 cited By 119 M.W. Lee article Shuwen200284 A recent study reveals that metamorphic volcanic and sedimentary rocks have survived deep subduction of continental crust in the Dabie Mountains, central China. These low-grade (LG) rocks are intercalated within the ultrahigh-pressure (UHP) metamorphic terrane and well preserve primary volcanic breccia structure and sedimentary bedding. The presence of coherent field relations between LG and UHP rocks suggests that LG rocks are not of exotic origin and therefore suffered from UHP metamorphism. They, however, did not record the UHP event likely due to slow reaction kinetics, and only experienced epidote-amphibolite to greenschist facies metamorphism and deformation at the retrograde stage of UHP rocks. The protolith age of c. 790 Ma and metamorphic age of 232.2 Ma obtained from LG rocks, which agree well with those from UHP rocks, also suggest that both LG and UHP rocks shared the same evolutionary history since Late-Proterozoic. Except for the lack of deformation and fluid during UHP metamorphism, the rapid subduction, short stay at mantle depths and rapid exhumation are necessary for the preservation of primary assemblage and fabric in LG rocks within deeply subducted continental crust. Article 2002 English 07053797 10.18814/epiiugs/2002/v25i2/003 Episodes 25 International Union of Geological Sciences 84 – 89 2 China; Dabie Shan; continental crust; metamorphic facies; metamorphic rock; subduction https://www.scopus.com/inward/record.uri?eid=2-s2.0-0036628409&doi=10.18814%2fepiiugs%2f2002%2fv25i2%2f003&partnerID=40&md5=d520fca10b3d262b680de272903de229 Cited by: 20; All Open Access, Hybrid Gold Open Access Dong Shuwen R. Oberhänsli R. Schmid Liu Xiaochun Tang Jiafu XUE Huaimin article Chen2002 The geometrical structure of the responsible faults of the 20 September 1999 Chi-Chi, Taiwan, earthquake (ML = 7.3, Mw = 7.6) and its aftershocks can be clearly depicted by well-located hypocenters and focal mechanisms of large aftershocks. The mainshock and two large aftershocks with ML = 6.8 were characterized by thrust faulting along a N-S striking fault plane dipping to the east. The underground structure of the Chelungpu fault, which is probably merging with the decollement beneath the Western Foothills, can be clearly associated with the seismicity pattern and the focal mechanisms of the three largest events. A group of deeper aftershocks including two moderate events (ML = 6.3 and 6.0, respectively) were located to the southeast of the mainshock along a fault plane dipping steeply to the west down to a depth of about 30 km. Our results suggest that the spatial pattern of the aftershocks in the southern part of the source area can be interpreted by a conjugate-fault system. This conjugate-fault system is comprised of the gently east-dipping Chelungpu fault and a steeply west-dipping deeper fault zone. Copyright 2002 by the American Geophysical Union. 2002 English 00948276 10.1029/2001GL014250 Geophysical Research Letters 29 Blackwell Publishing Ltd Institute of Earth Sciences, Academia Sinica, P.O. Box 1-55, Nankang, Taipei, Taiwan; Institute of Geophysics, National Central University, Chung-Li, Taiwan 8 Earthquakes; Geophysics; Underground structures, Chi-Chi , Taiwan; Conjugate faults; Earthquake sequences; Focal mechanism; Geometrical structure; Seismicity pattern; Spatial patterns; Thrust faulting, Faulting https://www.scopus.com/inward/record.uri?eid=2-s2.0-0037092375&doi=10.1029%2f2001GL014250&partnerID=40&md5=5db990901461a59c7cf18e2eea5d699d cited By 34 K.-C. Chen B.-S. Huang J.-H. Wang H.-Y. Yen article Mori2002255 2002 English 00963941 10.1029/2002EO000180 Eos 83 American Geophysical Union 255 Disaster Prevention Research Institute, Kyoto University, Japan; Geological Survey of Japan, AIST, Tsukuba, Japan; National Central University, Jungli, Taiwan 23 https://www.scopus.com/inward/record.uri?eid=2-s2.0-0011072550&doi=10.1029%2f2002EO000180&partnerID=40&md5=99c381adda310ec40a8586da7898b763 cited By 13 J. Mori H. Ito C.-Y. Wang article Catchings20022493 A 5-km-long, high-resolution seismic imaging survey across the San Andreas fault (SAF) zone and the proposed San Andreas Fault Observatory at Depth (SAFOD) drill site near Parkfield, California, shows that velocities vary both laterally and vertically. Velocities range from <1.0 km/sec near the surface to as much as 4.8 km/sec at 750-m depth. The lowest velocities (<1.0 to ∼3.0 km/sec) correspond to unconsolidated sediment, mudstone, and sandstone in the near surface, and the higher velocities (>4.0 km/sec) probably correspond to granitic rock of the Salinian block, which is exposed a few kilometers southwest of the SAF. The depth to the top of probable granitic rock varies laterally along the seismic profile but is about 600 m below the surface at the proposed SAFOD site. We observe a prominent, lateral low-velocity zone (LVZ) beneath and southwest of the surface trace of the SAF. The LVZ is about 1.5 km wide at 300-m depth but tapers to about 600 m wide at 750-m depth. At the maximum depth of the velocity model (750 m), the LVZ is centered approximately 400 m southwest of the surface trace of the SAF. Similar velocities and velocity gradients are observed at comparable depths on both sides of the LVZ, suggesting that the LVZ is anomalous relative to rocks on either side of it. Velocities within the LVZ are lower than those of San Andreas fault gouge, and the LVZ is also anomalous with respect to gravity, magnetic, and resistivity measurements. Because of its proximity to the surface trace of the SAF, it is tempting to suggest that the LVZ represents a zone of fractured crystalline rocks at depth. However, the LVZ instead probably represents a tectonic sliver of sedimentary rock that now rests adjacent to or encompasses the SAF. Such a sliver of sedimentary rock implies fault strands on both sides and possibly within the sliver, suggesting a zone of fault strands at least 1.5 km wide at a depth of 300 m, tapering to about 600 m wide at 750-m depth. Fluids within the sedimentary sliver are probably responsible for observed low-resistivity values. 2002 English 00371106 10.1785/0120010263 Bulletin of the Seismological Society of America 92 2493-2503 U.S. Geological Survey, 345 Middlefield Rd, Menlo Park, CA 94587, United States; U.S. Geological Survey, 345 Middlefield Rd., Menlo Park, CA 94587, United States; U.S. Geological Survey, 345 Middlefield Rd., Menlo Park, CA 94587, United States; Department of Geological Sciences, Virginia Tech, 4044 Derring Hall, Blacksburg, VA 24061-0420, United States; Geometrics Inc., 2190 Fortune Drive, San Jose, CA 95131, United States; Geometrics Inc., 2190 Fortune Drive, San Jose, CA 95131, United States 6 Granite; Imaging techniques; Landforms; Sandstone; Sediments; Surveying; Velocity measurement, Seismic imaging surveys, Seismology, crustal structure; fault zone; San Andreas Fault; seismic velocity; seismicity, United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-0036704542&doi=10.1785%2f0120010263&partnerID=40&md5=df6820e3515c778a01445f34d6b34a17 cited By 61 R.D. Catchings M.J. Rymer M.R. Goldman J.A. Hole R. Huggins C. Lippus article Tanaka2002227 The Chelungpu fault, a reverse fault with left lateral component dipping moderately to the east, was activated by the Chi-Chi earthquake (Mw = 7.6) in 21 September, 1999 with maximum vertical and lateral offsets of 5.6 m and 9.8 m. Characteristics of earthquake and related phenomena are contrasting between northern and southern regions along the Chelungpu fault. The northern region has (1) larger displacements (4 to 9 m), (2) low frequency seismic waves with higher velocity of slip surface, and (3) less disastrous except the most northern area compared to those in the southern region. Drilling into the Chelungpu fault was thus conducted at two locations, northern (Fengyuan) and southern (Nantou) sites, and successfully completed in March 2001. The project was motivated to explore the fundamental controlling factors of the mode of slip motion at northern and southern regions through analysis of intrafault materials. Meso- and microstructural examinations and measurements of static/ dynamic physical properties have been conducted for each drill core. The ongoing analyses have shown interesting results: (1) fault zone architecture is totally different between the northern and southern fault zones. The rocks are mainly composed of random fabric fault breccia with extremely thin fault gouge in the northern core, whereas the foliated fault breccia is dominantly associated with ultracataclasite and pseudotachylite in the southern core, (2) possible fault zones activated by the Chi-Chi earthquake can be listed up by combining geological, geophysical logging and reflection seismic data, which are 225 m and 330 fracture zones in the core from northern well and 177 m and 180 m fracture zones in the core from southern well, (3) water contents of the core of the 225 m rupture zone in the northern well attains up to 45 vol.%, and (4) some temperature rises were detected at 330 m fracture zone in the northern well and 180 m fracture zone in the southern well by temperature logging, which could be attributed to residual heat generated during the Chi-Chi earthquake or postseismic influx of hydrothermal fluid into the fault zones. 2002 English 10170839 10.3319/TAO.2002.13.3.227(CCE) Terrestrial, Atmospheric and Oceanic Sciences 13 Chinese Geoscience Union 227-251 Institute of Geophysics, National Central University, Chung-Li, Taiwan 3 breccia; Chi-Chi earthquake 1999; dip-slip fault; drilling; fault zone; microstructure; reverse fault, Chelungpu Fault; Taiwan https://www.scopus.com/inward/record.uri?eid=2-s2.0-0036752072&doi=10.3319%2fTAO.2002.13.3.227%28CCE%29&partnerID=40&md5=22abcf045b1771911d87be39765c5bec cited By 61 H. Tanaka C.-Y. Wang W.-M. Chen A. Sakaguchi K. Ujiie H. Ito M. Ando article Demske2002107 Palynomorphs from a palaeomagnetically dated Late Pliocene sediment core (3.6-2.35 Ma) reflect highly variable climatic conditions and repeated expansion of steppe and boreo-alpine vegetation. Mixed coniferous forests (Picea, Tsuga, Pinus) with associated broadleaved taxa (Quercus, Corylus, Ulmus, Tilia) were affected by dry and cold intervals already between 3.48 and 3.39 Ma. Peak records of non-arboreal pollen types and spores, including subarctic-boreo-alpine Selaginella selaginoides, evidence advances of open vegetation, which can be correlated to glacial marine oxygen isotope stages. A cooling trend occurred from 3.15 Ma to 2.5 Ma, documented by cold-dry intervals and increased fluctuations of Picea and Pinus. Around 3-2.9 Ma the palaeoclimate variation pattern shifted towards cold-dry and warm-moist oscillations. Cooling strengthened after 2.89 Ma and severely restricted Tsuga development. Cool and oligotrophic limnic conditions are documented by abundant Gonyaulax dinoflagellate cysts in the interval 2.65-2.57 Ma. Due to decreasing precipitation extensive areas with open steppe and rock-steppe vegetation became permanently established after 2.62 Ma. Dry conditions became a dominant environmental factor in the Baikal region, coeval in time with the Red Clay-Loess shift in northern China. This climatic transition can be explained as a consequence of major intensification of Northern Hemisphere Glaciation around 2.75 Ma evidenced by marine records of ice-rafted debris. © 2002 Elsevier Science B.V. All rights reserved. Article 2002 English 00310182 10.1016/S0031-0182(02)00251-1 Palaeogeography, Palaeoclimatology, Palaeoecology 184 Elsevier B.V. 107 – 129 1-2 Lake Baikal; Russian Federation; Siberia; Bacteria (microorganisms); Corylus; Corylus; Dinophyceae; Gonyaulax; Gonyaulax; Malvaceae; Picea; Picea; Pinus; Quercus; Quercus; Selaginella; Selaginella selaginoides; Selaginella selaginoides; Tilia; Tilia; Tsuga; Tsuga; Ulmus; Ulmus; lacustrine deposit; paleoclimate; paleoenvironment; palynology; Pliocene; vegetation history https://www.scopus.com/inward/record.uri?eid=2-s2.0-0036681467&doi=10.1016%2fS0031-0182%2802%2900251-1&partnerID=40&md5=c23e6705083199575419ec0e93d711fb Cited by: 38 Dieter Demske Barbara Mohr Hedi Oberhänsli article DAgostino200297 Approximately 600 km of high-resolution seismic reflection data were collected to investigate the late-Quaternary stratigraphic development of Lake Titicaca. The focus of this report is on two seismic sequence boundaries, which are interpreted as erosional surfaces formed at times of low lake level. The younger erosional surface occurs as much as 90 m below the present lake level and up to 8 m below the present sediment-water interface. This erosional surface is interpreted to be coeval with a well-documented early- to mid-Holocene lowstand, dated between ∼ 8000 and 3600 cal yr BP. An earlier and previously unknown erosional surface occurs at a sub-bottom depth of approximately 30 m, and as much as 240 m below the present lake level, which implies a major late-Pleistocene lowstand of Lake Titicaca. By extrapolation of sedimentation rates from the upper ∼ 14 m of sediment, we estimate the age of this older lowstand at > 90000 cal yr BP. Both lowstands of Lake Titicaca indicated by the seismic data are likely to have been a response to climatic change in the region. © 2002 Elsevier Science B.V. All rights reserved. Article 2002 10.1016/S0031-0182(01)00411-4 Palaeogeography, Palaeoclimatology, Palaeoecology 179 97 – 111 1-2 Bolivia; Peru; lake level; paleoclimate; Quaternary; seismic data; seismic reflection; seismic stratigraphy https://www.scopus.com/inward/record.uri?eid=2-s2.0-0037091908&doi=10.1016%2fS0031-0182%2801%2900411-4&partnerID=40&md5=5076a6c76cdcb2cdd30a46fac5a23a28 Cited by: 50; All Open Access, Green Open Access Karin D'Agostino Geoffrey Seltzer Paul Baker Sherilyn Fritz Robert Dunbar article Wang200237-1 The Chelungpu fault was activated by the 1999 Chi-Chi earthquake (Mw = 7.6), Taiwan. This fault exhibited extraordinarily large surface ruptures (up to 9.8 m) as well as underground fault slippages (up to 12 m) during the earthquake. These large displacements were concentrated along the northern portion of the fault, 40 km north of the epicenter. To prepare data for the future drilling of deep wells in this area, many shallow seismic reflection surveys were conducted to investigate the sites. An approximate 3D structure of the fault surface can be deduced by this cost-effective approach. Although the depth penetration may be limited (e.g., 3 km), the method still provides reliable information to study large ruptures, and to better plan future deep wells. 2002 English 00948276 10.1029/2001gl014496 Geophysical Research Letters 29 American Geophysical Union 37-1-37-3 Institute of Geophysics, National Central University, Chung-Li 32054, Taiwan 16 Cost effectiveness; Seismology; Structure (composition); Surveys, Fault slippages, Earthquakes, borehole; earthquake rupture; fault slip; seismic reflection; seismic survey, Chelungpu Fault; Taiwan https://www.scopus.com/inward/record.uri?eid=2-s2.0-0037104909&doi=10.1029%2f2001gl014496&partnerID=40&md5=8f749f97d58bf6c659ba5e7e206df647 cited By 20 C.-Y. Wang C.-L. Li H.-Y. Yen article Noe-Nygaard2001305 Within the framework of the Baikal Drilling Project (BDP), a 192 m long sediment core (BDP-96-1) was recovered from the Academician Ridge, a submerged topographic high between the North and Central Basins of Lake Baikal. Sedimentological, clay mineralogical and geochemical investigations were carried out on the core interval between 90 and 124 m depth, corresponding to ca. 2.4-3.4 Ma. The aim was to reconstruct the climatic and tectonic history of the continental region during the intensification of Northern Hemisphere glaciation in Late Pliocene time. A major climate change occurred in the Lake Baikal area at about 2.65 Ma. Enhanced physical weathering in the catchment, mirrored in the illite to smectite ratio, and temporarily reduced bioproduction in the lake, reflected by the diatom abundance, evidence a change towards a colder and more arid climate, probably associated with an intensification of the Siberian High. In addition, the coincident onset of distinct fluctuations in these parameters and in the Zr/Al ratio suggests the beginning of the Late Cenozoic high amplitude climate cycles at about 2.65 Ma. Fluctuations in the Zr/Al ratio are traced back to changes in the aeolian input, with high values in warmer, more humid phases due to a weaker Siberian High. Assuming that the sand content in the sediment reflects tectonic pulses, the Lake Baikal area was tectonically active during the entire investigated period, but in particular around 2.65 Ma. Tectonic movements have likely led to a gradual catchment change since about 3.15 Ma from the western towards the eastern lake surroundings, as indicated in the geochemistry and clay mineralogy of the sediments. The strong coincidence between tectonic and climatic changes in the Baikal area hints at the Himalayan uplift being one of the triggers for the Northern Hemisphere Glaciation. © 2001 Elsevier Science B.V. All rights reserved. Article 2001 English 00310182 10.1016/S0031-0182(01)00320-0 Palaeogeography, Palaeoclimatology, Palaeoecology 174 305 – 326 4 Russian Federation; Bacillariophyta; geochemistry; lacustrine deposit; paleoclimate; Pliocene; sedimentology; tectonic evolution; weathering https://www.scopus.com/inward/record.uri?eid=2-s2.0-0035472635&doi=10.1016%2fS0031-0182%2801%2900320-0&partnerID=40&md5=e9d3bd7ac1447f36f23ebb65d5698225 Cited by: 38 Nanna Noe-Nygaard Erik Otto Heiberg article Duchkov2001298 Thermal conductivity of rocks is a key parameter in heat flow determination. Thermal conductivity of the Baikal bottom sediments in cores from first underwater boreholes (BDP-93 and BDP-96) was measured by a needle probe and a thermal-conductivity comparator, and the two methods showed a difference of up to 30-50% in the values of both thermal conductivity and heat flow. In this study we used a new method implying evaluation of thermal conductivity of sediments through interpretation (inversion modeling) of temperature field recovery in boreholes after the cessation of drilling. The modeling parameters are steady-state temperature and thermal conductivity of bottom sediments at a depth of temperature monitoring. As a result, it was concluded that the needle probe measurements are reliable, and the thermal-conductivity comparator cannot be used to study unconsolidated sediments with water contents above 40%. The obtained estimates of steady-state temperature and geothermal gradient confirmed that the heat flow is relatively low (about 50 mW/m2) in the Bugul'deika saddle (BDP-93) and high (78 mW/m2, an updated value) in the axial part of the Akademichesky Ridge (BDP-96). The new method allowed us to estimate, for the first time, the thermal-diffusivity coefficient and the specific heat capacity of the Baikal sediments. Thus, the numerical analysis of temperature monitoring data permits estimation of all geothermal parameters of sediments. Article 2001 Russian 00167886 Geologiya i Geofizika 42 298 – 307 1-2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-26044455653&partnerID=40&md5=65616943e69cbb2ba9940b74ffd2f146 Cited by: 3 A.D. Duchkov T.-C. Lee S.G. Morozov article Weinberg2001130 Spicules have been investigated in Late Pliocene core samples from the borehole BDP-96-1. The samples have been dated paleomagnetically. A total of 42 spicule types have been discovered, of which 15 are found in modern Baikal sponges and 27 are not. Analysis of the range of species and quantitative indices of the spicules in bottom sediments has revealed three stages of sponge-fauna development: 3.1-2.9, 2.9-2.5, and 2.5-2.1 Ma BP. The sponge fauna of the first stage is indicative of warm-water conditions. Most of thermophilic and fossil species disappeared from the second stage, which points to a dramatic cooling. At the third stage, regeneration of the sponge fauna began. However, it did not reach the efflorescence of the first stage. The results are in agreement with the palynological and diatom analysis of the core samples from the investigated depth range. Article 2001 Russian 00167886 Geologiya i Geofizika 42 130 – 137 1-2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-26044474216&partnerID=40&md5=ba64e85ace5c2e833ce42c8421d176f0 Cited by: 3 E.V. Weinberg article Khlystov2001373 The paper presents new details of the structure of the basement and sedimentary cover of the southwestern edge of the North Baikal basin. The basement structure involves smaller-scale structures (Maloe More basin, Zama basin, and Zunduk-Zama horst), which, in turn, comprise third-order features. The presence of several en-echelon NE striking sub-basins within the Maloe More and Zama basins indicates that the tectonic framework of the region formed by listric and dextral faulting. Seismostratigraphy data and analysis of uppermost bottom sediments from BDP-96 and BDP-98 cores revealed three seismic layers in the sediment section, which are separated by discontinuities and can be correlated with deposits exposed on land in the neighboring Ol'khon region. Unit A' (X) correlates with the Lower-Middle Oligocene Ular'yar Formation, unit A, with the Lower-Middle Miocene Tagai Formation, and unit B, with the Upper Miocene-Pliocene Sasa Formation and with Quaternary deposits. The upper section of the Maloe More fill includes a separate seismic horizon correlatable with a layer of widely distributed fine-grained sand. Unit B, comprises three deposition centers within the limits of the Maloe More basin, i.e., large lakes existed in the region prior to the final stage of transgression from the North Baikal basin. Thus, the southwestern edge of the Baikal basin has an intricate structure and underwent a complex evolution. Article 2001 Russian 00167886 Geologiya i Geofizika 42 373 – 383 1-2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-26044445499&partnerID=40&md5=c387d93b5a682089a1d8a40b4c5507a1 Cited by: 6 O.M. Khlystov V.D. Mats M. De Batist article Antipin200119 The new 600-m drill core BDP-98 from the Academician Ridge of Lake Baikal recovered a continuous sedimentary record of the past 10 Ma. The entire section is represented by lacustrine sediments, which gradually change from distal deltaic facies at the bottom of the section to fine undisturbed hemipelagic sediments of the upper 300-m interval. The entire 10-Ma lacustrine section contains abundant diatoms, thus allowing extension of Plio-Pleistocene diatom and biogenic silica records into the Miocene. Above the Matuyama/Gauss paleomagnetic reversal boundary, the BDP-98 record contains clearly delineated glacial/interglacial lithologic cycles. Below this boundary the diatom signal is quite different: average diatom contents are higher and variations are of lower amplitude. Although most likely paleoclimatic in origin, these variation presumably reflect past changes in the moisture regime of southeast Siberia under conditions of warm subtropical climate during the Miocene and Early-Middle Pliocene. The continuous BDP-98 drill core, which covers the hiati present in the composite continental sections of the Baikal region, is a key section for reconstructing the Neogene-Quaternary climatic evolution of continental Asia. The BDP-98 section also places several important time constraints on the rifting history of Lake Baikal by providing reliable correlation of lithological and physical properties of the drill core sediments with calculated positions of the acoustic reflection boundaries interpreted from multichannel seismic studies. The lithologic composition indicates that, on the stable block of Academician Ridge where the BDP-96 and BDP-98 drill sites are located, acoustic reflection boundaries are not associated with major erosional events, but instead result from changes in sediment density and composition. Several lithologic indices further suggest that significant changes have occurred in the physics and chemistry of Lake Baikal waters, affecting the carbonate equilibrium and oxygen regime of Baikal. © 2001 Published by Elsevier Science Ltd. Article 2001 English 10406182 10.1016/S1040-6182(01)00016-7 Quaternary International 80-81 19 – 36 Asia; Russian Federation; Cenozoic; lacustrine deposit; sediment core https://www.scopus.com/inward/record.uri?eid=2-s2.0-0034806271&doi=10.1016%2fS1040-6182%2801%2900016-7&partnerID=40&md5=7bb7ff777e21984b1f0bb21c936c1b8f Cited by: 55 V. Antipin T. Afonina O. Badalov E. Bezrukova A. Bukharov V. Bychinsky A.A. Dmitriev R. Dorofeeva A. Duchkov O. Esipko T. Fileva V. Gelety V. Golubev A. Goreglyad I. Gorokhov A. Gvozdkov Y. Hase N. Ioshida E. Ivanov I. Kalashnikova G. Kalmychkov E. Karabanov S. Kashik T. Kawai E. Kerber B. Khakhaev O. Khlystov G. Khursevich M. Khuzin J. King K. Konstantinov V. Kochukov M. Krainov V. Kravchinsky N. Kudryashov L. Kukhar M. Kuzmin K. Nakamura Sh Nomura E. Oksenoid J. Peck L. Pevzner A. Prokopenko V. Romashov H. Sakai I. Sandimirov A. Sapozhnikov K. Seminsky N. Soshina A. Tanaka L. Tkachenko M. Ushakovskaya D. Williams article Prokopenko200137 The records of diatom abundance, clay fraction content and magnetic susceptibility from Lake Baikal drill core BDP-96-1 reflect the climate-driven Plio-Pleistocene evolution of the Lake Baikal sedimentation system. In addition to the dramatic variations in the proxy records in response to the Northern Hemisphere ice ages, the Baikal record also indicates climatic deterioration from 2.8 to 2.5 Ma BP with evidence for an early Siberian glaciation around the Matuyama/Gauss paleomagnetic reversal boundary. The drill core data also allow correlation of this early glacial interval with the basin-wide seismic sequence boundary B10, which marks the unconformity produced by the active neotectonic phase in the Baikal rift zone. At the BDP-96 drill site, however, the strong B10 acoustic reflection was produced not by an erosional boundary, but instead by deposition of glacial clay layers. The paleomagnetic age scale of BDP-96-1 constrains the upper age of the Neobaikalian uplift/subsidence phase in the Baikal-Sayan region at ca. 2.5 Ma BP. The coincident timing of the paleoclimatic and tectonic events recorded in Lake Baikal sediments suggests a close causal link between regional tectonics and climate and indicate that the late Pliocene uplift contributed to the initiation of the early glaciation in southeast Siberia between 2.8 and 2.6 Ma BP by creating an elevated terrain with lower snowline, favorable for alpine glaciation, and by changing the heat balance of the region. © 2001 Elsevier Science Ltd and INQUA. All rights reserved. Article 2001 English 10406182 10.1016/S1040-6182(01)00017-9 Quaternary International 80-81 37 – 46 Russian Federation; lacustrine deposit; neotectonics; paleoclimate; paleomagnetism; sediment core https://www.scopus.com/inward/record.uri?eid=2-s2.0-0034815367&doi=10.1016%2fS1040-6182%2801%2900017-9&partnerID=40&md5=6cb7a4d5f3d2654223095d73f4e99c77 Cited by: 15 Alexander A. Prokopenko Eugene B. Karabanov Douglas F. Williams Mikhail I. Kuzmin Galina K. Khursevich Alexander A. Gvozdkov article Krainov200187 Two boreholes on the Akademichesky Ridge, 100 and 200 m deep (BDP-96-1 and BDP-96-2), were drilled and cored continuously as part of the Baikal Drilling Project. Results of low-frequency magnetic susceptibility measurements of the two cores were correlated with the SPECMAP oceanic oxygen isotope curve, and a composite section was compiled. The SPECMAP curve and the magnetic susceptibility of the BDP-96 cores showed a good fit. Frequency analysis of time variations in magnetic susceptibility showed a periodicity of the paleoclimate signal with intervals of 23, 35, 41, 52, 68, 85, 106, and 164 ka. The periods of 23, 41, 52, and 106 ka correspond to cycles of precession, inclination of the Earth's axis, an eccentricity harmonic overlapped with inclination, and the Earth's orbit eccentricity itself, respectively. The periods of 35, 68, and 164 ka, distinguished for the first time in magnetic susceptibility studies but noted earlier in biogenic silica analysis, reflect different eccentricity harmonics, and the period of 68 ka bears an effect of precession. The period of 85 ka has never been revealed before in the climate record and is most likely related to regional periodicity rather than to any astronomic cycles. Article 2001 Russian 00167886 Geologiya i Geofizika 42 87 – 97 1-2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-0037691252&partnerID=40&md5=d9bfd7cfba9ef3551176c16e015c4272 Cited by: 6 M.A. Krainov V.A. Kravchinskii J.A. Peck H. Sakai J.W. King M.I. Kuz'min article Fedorin2001186 The paper presents a new method of U and Th determination in bottom sediments implying synchrotron radiation with monochromatic beams at different energies, registration, and iterative joint processing of the resultant XRF (X-ray fluorescent) spectra series. The validity of the new method was proved by comparison of U and Th determinations by XRF-SR in different sediment samples with earlier INAA and ICP-MS results for the same samples. Profiles of U and Th were measured at the sampling rate of 2 ka in a drilling core (BDP-96-2) of bottom sediments from Lake Baikal deposited 40 to 780 ka BP. Oscillations of U contents and U/Th ratios record global climate change throughout the Brunhes epoch (780 ka BP), and the response of these "warm" proxies is similar to that observed earlier in shorter cores spanning the last two interglacials (220-0 ka BP). Article 2001 Russian 00167886 Geologiya i Geofizika 42 186 – 193 1-2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-0001940231&partnerID=40&md5=c3c75e98ba95c9acfdb403efd4637543 Cited by: 4 M.A. Fedorin E.L. Gol'dberg V.A. Bobrov O.M. Khlystov M.A. Grachev article Liu2001199 The pre-pilot drillhole CCSD-PPI, Chinese Continental Scientific Drilling Project (CCSD), with depth of 432 m, is located in the Donghai area in the southwestern Sulu terrane. The core samples are mainly comprised of paragneiss, orthogneiss and ultramafic rock with minor intercalated layers of eclogite and phengite-bearing kyanite quartzite. All analyzed paragneiss and orthogneiss samples were overprinted on amphibolite facies retrograde metamorphism. Coesite and coesite-bearing ultrahighpressure (UHP) mineral assemblages were identified by Raman spectroscopy and electron microprobe analysis as inclusions in zircons separated from paragneiss, eclogite and phengite-bearing kyanite quatzite samples. In the paragneiss samples, UHP mineral inclusion assemblages mainly consist of Coe + Omp+ Grt+ Phe, Coe + Jd + Phe + Ap preserved in the mantles (M) and rims (R) of zircons. These UHP mineral inclusion assemblages yield temperatures of 814-852 °C and pressures of ≥28 kbar, presenting the P-T condition of UHP peak metamorphism of these country rocks. According to the mineral inclusions and cathodoluminescence images of zircons, the orthogneisses can be divided into two types: UHP (OGI) and non-UHP (OG2). In OGI orthogneisses, low-pressure mineral inclusion assemblage, mainly consisting of Qtz + Phe +Ab +Ksp + Ap, were identified in zircon cores (C), while coesite or coesite-bearing UHP mineral inclusions were identified in the mantles (M) and rims (R) of the same zircons. These features suggest that the OG1 orthogneisses, together with the paragneisses, phengitebearing kyanite quartzite and eclogite experienced widespread UHP metamorphism in the Sulu terrane. However, in the zircons of OG2 orthogneiss samples, no UHP mineral inclusions were found. Inclusions mainly comprised Qtz + Phe + Ap and were identified in cores (C), mantles (M) and rims (R) of OG2 zircons; the cathdoluminescence images of all analyzed zircons showed clear zonings from cores to rims. These features indicate that the OG2 orthogneisses in pre-pilot drillhole CCSD-PP1 did not experience UHP metamorphism. Therefore, we should not rule out the possibility that some orthogneisses in Sulu terrane might represent relatively low-pressure granitic intrusives emplaced after the UHP event. © 2001 Elsevier Science B.V. All rights reserved. Article 2001 English 00244937 10.1016/S0024-4937(01)00064-0 Lithos 59 199 – 215 4 China; drilling; mineralogy; orthogneiss; paragenesis; zircon https://www.scopus.com/inward/record.uri?eid=2-s2.0-0035664263&doi=10.1016%2fS0024-4937%2801%2900064-0&partnerID=40&md5=ad7691f3b4ed0edf48ed53189e930869 Cited by: 191 Fulai Liu Zhiqin Xu Ikuo Katayama Jingsui Yang Shigenori Maruyama J.G. Liou article Cross20011 A simple mass balance model provides insight into the hydrologic, isotopic, and chemical responses of Lake Titicaca to past climatic changes. Latest Pleistocene climate of the Altiplano is assumed to have been 20% wetter and 5°C colder than today, based on previous modeling. Our simulation of lacustrine change since 15,000 cal yr B.P. is forced by these modeled climate changes. The latest Pleistocene Lake Titicaca was deep, fresh, and overflowing. The latest Pleistocene riverine discharge from the lake was about 8 times greater than the modern average, sufficient to allow the expansion of the great paleolake Tauca on the central Altiplano. The lake δ18O value averaged about - 13‰ SMOW (the modern value is about -4.2‰). The early Holocene decrease in precipitation caused Lake Titicaca to fall below its outlet and contributed to a rapid desiccation of paleolake Tauca. Continued evaporation caused the 100-m drop in lake level, but only a slight (1-2‰) increase (relative to modern) in δ18O of early Holocene lake waters. This Holocene lowstand level of nearly 100 m was most likely produced by a precipitation decrease, relative to modern, of about 40%. The lake was saline as recently as 2000 cal yr B.P. The timing of these hydrologic changes is in general agreement with calculated changes of insolation forcing of the South American summer monsoon. © 2001 University of Washington. Article 2001 10.1006/qres.2001.2244 Quaternary Research 56 1 – 9 1 Bolivia; Lake Titicaca; Peru; geochemistry; lake level; paleoclimate; paleohydrology; paleolimnology; Quaternary https://www.scopus.com/inward/record.uri?eid=2-s2.0-0035413201&doi=10.1006%2fqres.2001.2244&partnerID=40&md5=63f69274f3ce8d9fc64eef7cf011f5fd Cited by: 73; All Open Access, Green Open Access Scott L. Cross Paul A. Baker Geoffrey O. Seltzer Sherilyn C. Fritz Robert B. Dunbar article Khursevich200147 Three new extinct taxa of the genus Stephanodiscus Ehrenberg (S. williamsii sp., nov., S. princeps sp. nov., S. yukonensis var. antiquus var. nov.) and four new extinct species and two new extinct varieties of the genus Cyclotella (Kützing) Brébisson (C. iris var. insueta var. nov., C. tempereiformica sp. nov., C. distincta sp. nov., C. comtaeformica sp. nov., C. comtaeformica var. spinata var. nov. and C. praeminuta sp. nov.) are described from Upper Cenozoic lacustrine sediments of Lake Baikal (boreholes BDP-96-1 and BDP-96-2). The narrow biostratigraphic ranges of the new taxa warrant their use as index-fossil species for defining a diatom zonation, for accurate correlation and age control of Lake Baikal sediments. The comparative morphological analysis of the newly described Cyclotella taxa allowed us to trace the evolution of morphological features in these diatoms through time. The short time intervals during which the Stephanodiscus taxa existed in ancient Baikal imply that these species were unable to adapt to rapidly changing paleoecological and paleolimnological conditions caused by abrupt Pleistocene climatic fluctuations. Article 2001 English 00262803 10.2113/47.1.47 Micropaleontology 47 47 – 71 1 Russian Federation; biostratigraphy; Cenozoic; diatom; lacustrine deposit; new species; paleoclimate https://www.scopus.com/inward/record.uri?eid=2-s2.0-0035017197&doi=10.2113%2f47.1.47&partnerID=40&md5=1998a0f63aeace2f361a7be2d35f66bc Cited by: 21 G.K. Khursevich E.B. Karabanov A.A. Prokopenko D.F. Williams M.I. Kuzmin S.A. Fedenya article Baker200120 Article 2001 Geotimes 46 20 – 21 12 https://www.scopus.com/inward/record.uri?eid=2-s2.0-73549105250&partnerID=40&md5=ef812b9e410ac9102b2ed40373ab641c Cited by: 0 Paul A. Baker Sherilyn C. Fritz Geoffrey O. Seltzer article Bezrukova200198 Two boreholes, BDP-96-1 (200 m thick) and BDP-96-2 (100 m thick), drilled at the top of the underwater Akademichesky Ridge at 53°41′48″N and 108°21′06″, gave two parallel cores which were dated paleomagnetically. The correlation of the paleomagnetic data with the global magnetic scale has shown the age of the sediments exposed at a depth of 200 m to be 5 Ma. The average sedimentation rate was constant, about 4 cm/ka. Earlier palynological studies of core samples from BDP-96-1 were performed at 2 m intervals, which corresponds to the period of ∼45-50 ka. In this paper, we present results of a detailed palynological analysis of the upper 30 m of the core performed at 20 cm intervals (4-5 ka). The age of the investigated core from BDP-96-1 covers most of the Brunhes epoch. Taking into account the lost upper 630 cm, it matches the time range from 170 to 780 ka BP. Palynological analysis of the sediments from the range under discussion revealed 13 epochs in the development of the regional flora structure: seven epochs of predominance of forest plant formations and six epochs of its significant degradation. The epochs are correlated with the stages of changes in the volume of global ice, recorded in the marine oxygen isotope scale. It is difficult to determine the extents of the coolings, because spores and pollen are scarce in the sediments of these epochs. However, it is apparent that forests did not disappear from East Siberia during the coolings. All main arboreal species now growing there persisted during Pleistocene glaciations. The structure of the vegetative cover underwent profound changes. The areas occupied by forests decreased. Larch and spruce north-taiga forests were predominant under the humid cold conditions of the beginning of interglacials and the end of glaciations; they were then replaced by fir and cedar pine forests. Larch-pine and cedar pine middle-taiga forests expanded under the moderately warm and relatively dry climate of the mid-interglacials. Obviously, this was accompanied by a wide spread of steppe vegetation. A comparison of the frequency and habit of changes in vegetation type in the study region 170-780 ka BP with those in various regions of the Northern Hemisphere demonstrates that the East Siberian vegetation responded to global climatic changes synchronously with the vegetations of other regions. Article 2001 Russian 00167886 Geologiya i Geofizika 42 98 – 107 1-2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-18044398187&partnerID=40&md5=628c0545be2a67918d7eef02183b2505 Cited by: 4 E.V. Bezrukova P.P. Letunova article Xiao20013 A combined study of major and trace elements, fluid inclusions and oxygen isotopes has been carried out on garnet pyroxenite from the Raobazhai complex in the North Dabie Terrane (NDT). Well-preserved compositional zoning with Na decreasing and Ca and Mg increasing from the core to rim of pyroxene in the garnet pyroxenite indicates eclogite facies metamorphism at the peak metamorphic stage and subsequent granulite facies metamorphism during uplift. A P-T path with substantial heating (from c. 750 to 900 °C) after the maximum pressure reveals a different uplift history compared with most other eclogites in the South Dabie Terrane (SDT). Fluid inclusion data can be correlated with the metamorphic grade: The fluid regime during the peak metamorphism (eclogite facies) was dominated by N2-bearing NaCl-rich solutions, whereas it changed into CO2-dominated fluids during the granulite facies retrograde metamorphism. At a late retrograde metamorphic stage, probably after amphibolite facies metamorphism, some external low-salinity fluids were involved. In situ UV-laser oxygen isotope analysis was undertaken on a 7 mm garnet, and impure pyroxene, amphibole and plagioclase. The nearly homogenous oxygen isotopic composition (δ18OVSMOW=c. 6.7‰) in the garnet porphyroblast indicates closed fluid system conditions during garnet growth. However, isotopic fractionations between retrograde phases (amphibole and plagioclase) and garnet show an oxygen isotopic disequilibrium, indicating retrograde fluid-rock interactions. Unusual MORB-like rare earth element (REE) patterns for whole rock of the garnet pyroxenite contrast with most ultra-high-pressure (UHP) eclogites in the Dabie-Sulu area. However, the age-corrected initial εNd(t) is - 2.9, which indicates that the protolith of the garnet pyroxenite was derived from an enriched mantle rather than from a MORB source. Combined with the present data of oxygen isotopic compositions and the characteristics N2 content in the fluid inclusions, we suggest that the protolith of the garnet pyroxenite from Raobazhai formed in an enriched mantle fragment, which has been exposed to the surface prior to the Triassic metamorphism. Article 2001 English 02634929 10.1046/j.1525-1314.2001.00290.x Journal of Metamorphic Geology 19 3 – 19 1 China; eclogite; geochemistry; granulite; metamorphism https://www.scopus.com/inward/record.uri?eid=2-s2.0-0035070204&doi=10.1046%2fj.1525-1314.2001.00290.x&partnerID=40&md5=12c2e305335003411b2d4fd3f11352ee Cited by: 83 Y.L. Xiao J. Hoefs A.M. Van Den Kerkhof S.G. Li article Lee2001763 Downhole-measured compressional- and shear-wave velocities acquired in the Mallik 2L-38 gas hydrate research well, northwestern Canada, reveal that the dominant effect of gas hydrate on the elastic properties of gas hydrate-bearing sediments is as a pore-filling constituent. As opposed to high elastic velocities predicted from a cementation theory, whereby a small amount of gas hydrate in the pore space significantly increases the elastic velocities, the velocity increase from gas hydrate saturation in the sediment pore space is small. Both the effective medium theory and a weighted equation predict a slight increase of velocities from gas hydrate concentration, similar to the field-observed velocities; however, the weighted equation more accurately describes the compressional- and shear-wave velocities of gas hydrate-bearing sediments. A decrease of Poisson's ratio with an increase in the gas hydrate concentration is similar to a decrease of Poisson's ratio with a decrease in the sediment porosity. Poisson's ratios greater than 0.33 for gas hydrate-bearing sediments imply the unconsolidated nature of gas hydrate-bearing sediments at this well site. The seismic characteristics of gas hydrate-bearing sediments at this site can be used to compare and evaluate other gas hydrate-bearing sediments in the Arctic. 2001 English 00168033 10.1190/1.1444966 Geophysics 66 Society of Exploration Geophysicists 763-771 U.S. Geological Survey, Denver Federal Center, Box 25046, MS 939, Denver, Colorado 80225, United States 3 Elasticity; Hydrates; Pore size; Sediments; Velocity; Gases; Hydration; Poisson ratio; Shear flow; Shear waves, Hydrate-bearing sediments; Compressional; Effective medium theories; Elastic properties; Gas hydrate bearing sediments; Gas hydrate concentrations; Gas hydrate saturations; Sediment porosities; Shear wave velocity, Geophysics; Gas hydrates, elastic property; gas hydrate; P-wave; S-wave; sediment; seismic velocity https://www.scopus.com/inward/record.uri?eid=2-s2.0-0035328506&doi=10.1190%2f1.1444966&partnerID=40&md5=db28418584bf04d929f35d6d1274fab7 cited By 82 M.W. Lee T.S. Collett article Franz2001322 Metabasites in the high-pressure unit of the southern Dabie Shan (eastern China) contain quartz veins with high-pressure mineral assemblages. Two veins with the parageneses quartz-paragonite-ankerite-rutile and quartz-kyanite-talc-zoisite-rutile-calcite (pseudomorph after aragonite) as well as quartz-kyanite-paragonite- garnet-omphacite were investigated in detail. Host rocks of these veins are garnet amphibolites with eclogitic relics and quartz eclogites, respectively. The oldest phase of deformation (DI) is recorded in the eclogite, which displays a schistosity with shape alignment of high-pressure minerals such as omphacite, phengite and garnet. An estimate of the metamorphic P-T conditions yields 19-21 kbar at 570-620 °C for the eclogites. Fluid inclusion studies reveal a primary, low-salinity aqueous fluid phase responsible for the formation of the quartz veins. This is in correspondence with calculations of phase equilibrium curves on minerals of the vein paragenesis, which yield P-T conditions of 19.4 kbar and 591 °C in the presence of an aqueous fluid phase. Geochronology using the U-Pb system of rutile gives evidence for a Triassic minimum age of 207-221 Ma for the vein formation, which fits in the geotectonic framework of the orogen. This rather wide age range arises from the heterogeneous nature of the initial lead isotopic composition, reflecting the heterogeneous sources of the lead and the fluid phase. Part of the fluid was probably generated by prograde dehydration reactions in the country rocks of the veins, whereas strong evidence is also given for the derivation from an older basement, which also underwent subduction. The veins may have formed by extensive hydraulic fracturing or by volume reduction during eclogitisation of the crust. Subsequent to the formation of the veins, great parts of the high-pressure rocks experienced an intensive, syn-tectonic (D2) amphibolite facies metamorphism at 8.5-10.5 kbar and 590-645 °C, indicating isothermal decompression during exhumation. In the course of this exhumation, pseudosecondary CO2 inclusions were trapped in quartz of the veins. The last recorded stage of the retrograde overprint took place under static, greenschist facies conditions (450-480 °C) in the stability field of kyanite. The shape of the metamorphic P-T path for this stage is reflected by the fluid phase, which either re-equilibrated during this event or penetrated the rock on fractures. These findings show that fluid flow during subduction-related high-pressure metamorphism and subsequent uplift is rather complex; the fluid phase may originate from different sources and may interact with country rocks in the form of a chromatographic column transforming mineral assemblages, and also changing its own character. Article 2001 English 00107999 10.1007/s004100000233 Contributions to Mineralogy and Petrology 141 322 – 346 3 China; deformation; eclogite; exhumation; fluid flow; metamorphism; P-T conditions; P-T-t path https://www.scopus.com/inward/record.uri?eid=2-s2.0-0034959385&doi=10.1007%2fs004100000233&partnerID=40&md5=e48d3e46464ccf8b475e5f954f56ecb1 Cited by: 163 Leander Franz Rolf L. Romer Reiner Klemd Robert Schmid Roland Oberhänsli Thomas Wagner Dong Shuwen article Solotchina2001146 By comparing the compositions of glacial and interglacial intervals of the Late Pliocene, Pleistocene, and Holocene from different parts of Lake Baikal, we demonstrate the use of the Baikal clay mineral associations as indicators of past changes of environment and climate. The methodical part of this work discusses the optimal sample preparation techniques and develops the previously suggested method for structural modeling of X-ray diffraction patterns as the most suitable for studying the Baikal sediments. The clay mineral associations in the Selenga delta area and at the Akademichesky Ridge are very similar, thus indicating a minor influence of local sediment sources on their formation. The similarities revealed by this comparison indicate uniformity of the Baikal catchment basin in terms of the processes of erosion, weathering, and supply of sediments. Despite the conditions of continuous hemipelagic sedimentation at the sites where deep drilling took place, both drill cores reveal a strong relation between the composition of clay mineral associations and paleoclimatic conditions. Intervals if glacial sediments during both the Late Pleistocene and the Late Pliocene are similar and are characterized by dramatic enrichment in well-crystallized mica (muscovite) and plagioclase, indicating intensification of physical weathering under cold climatic conditions. Interglacial intervals are enriched in fine illite, which suggests that it is a secondary mineral, the product of chemical weathering. In addition, the content of smectite layers in mixe layer illite-smectite increases during interglacials, which is also likely to imply a warmer and more humid climate. The lower interval of the BDP-96 core with the age over 4.5 Ma is characterized by an anomalous composition: high content of illite-smectite with a high concentration of smectite component, the presence of chlorite-smectite, and low contents of illite and muscovite. This specific mineral association has formed under climatic conditions much warmer than at present. Article 2001 Russian 00167886 Geologiya i Geofizika 42 146 – 156 1-2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-0008807929&partnerID=40&md5=cce10ade76d69d170e9add8be5bd2b80 Cited by: 11 E.P. Solotchina A.A. Prokopenko M.I. Kuz'min A.N. Vasilevskii S.G. Shul'zhenko article Khursevich2001108 The Baikal bottom sediments (borehole BDP-96-2) are stratigraphically characterized in detail (with a 500 year resolution) within the Brunhes Chron. The sediment section 35 m thick shows a distribution of diatoms (25 species and varieties), sponge spicules, and golden-algae cysts. Thirty-one local diatom zones are recognized in the section, providing a detailed stratigraphic division of the Baikal sediments. The distribution of diatom frustules and the diatom zones are correlated with the marine isotope stratigraphy. Climate played an important role in the formation of species of plankton diatoms in the lake. More than 21 new species of diatoms appear and then disappear in the section. Diatom species extinguished when glaciations began, and new species appeared during interglaciations. This suggests that the evolution of plankton diatoms in Baikal is under climatic control. Article 2001 Russian 00167886 Geologiya i Geofizika 42 108 – 129 1-2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-0012522733&partnerID=40&md5=55aa0d0c3b2c34d8203972ffe152b813 Cited by: 27 G.K. Khursevich E.B. Karabanov A.A. Prokopenko D.F. Williams M.I. Kuz'min S.A. Fedenya A.N. Gvozdkov E.V. Kerber article Moore2001221 Density measurements of 1600 samples of core from 889 to 3097 m depth below sea level in the Hawaii Scientific Drilling Program hole near Hilo, Hawaii show marked differences between the basaltic rock types and help define stratigraphy in the hole. Water-saturated densities of subaerial lava flows (occurring above 1079 m depth) have the broadest range because of the large density variation within a single lava flow. Water-saturated densities commonly range from 2.0 to 3.0 with an average of 2.55 ± 0.24 g/cc. Dikes and sills range from 2.8 to 3.1 g/cc). Densities of hyaloclastite commonly range from 2.3 to 2.7, with an overall average of about 2.5 g/cc. The low-density of most hyaloclastite is due primarily to palagonitization of abundant glass and presence of secondary minerals in the interstices between fragments. Four principal zones of pillow lava, separated by hyaloclastite, occur in the drill core. The shallowest (1983-2136 m) is paradoxically the densest, averaging 3.01 ± 0.10 g/cc. The second (2234-2470 m) is decidedly the lightest, averaging 2.67 ± 0.13 g/cc. The third (2640-2790 m) and fourth (2918-bottom at 3097 m) are high, averaging 2.89 ± 0.17 and 2.97 ± 0.08 g/cc, respectively. The first pillow zone includes degassed pillows i.e. lava erupted on land that flowed into the sea. These pillows are poor in vesicles, because the subaerial, one-atmosphere vesicles were compressed when the flow descended to deeper water and higher pressure. The second (low-density, non-degassed) pillow zone is the most vesicle-rich, apparently because it was erupted subaqueously at a shallow depth. The higher densities of the third and fourth zones result from a low vesicularity of only a few percent and an olivine content averaging more than 5% for the third zone and about 10% for the fourth zone. The uppermost hyaloclastite extending about 400 m below the bottom of the subaerial basalt is poorly cemented and absorbs up to 6 wt% of water when immersed. Progressing downward the hyaloclastite absorbs less water and becomes better cemented. This change is apparently due to palagonitization of glass and addition of secondary minerals in the deeper older hyaloclastite, a process favored by the increase of temperature with depth. The cementation is largely complete at 1800 m depth where the temperature attains about 20°C. The zone of freshest, uncemented hyaloclastite represents the weakest rock in the drill hole and is a likely level for tectonic or landslide disruption. © 2001 Published by Elsevier Science B.V. Article 2001 English 03770273 10.1016/S0377-0273(01)00242-6 Journal of Volcanology and Geothermal Research 112 221 – 230 1-4 United States; Landslides; Stratigraphy; Thermal effects; Volcanic rocks; basalt; density; hyaloclastite; pillow lava; stratigraphy; Hyaloclastite; Volcanoes https://www.scopus.com/inward/record.uri?eid=2-s2.0-0035694617&doi=10.1016%2fS0377-0273%2801%2900242-6&partnerID=40&md5=00958742710669c478847a2692aad7f3 Cited by: 59 James G Moore article Sandimirov2001194 We propose a method for dating Baikal deep-water sediments from the ratios of radioactive isotopes of Th and U in various fractions of the authigenic part of the sediments. We have determined the Th-U age of six horizons of the borehole BDP-96-2 and the average parameters of gravitational consolidation of the sediments. The extrapolated Th-U ages show a good correlation with paleomagnetic data throughout the core of BDP-96-2. Article 2001 Russian 00167886 Geologiya i Geofizika 42 194 – 205 1-2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-0041567475&partnerID=40&md5=b6ce6b6894dd78352d32a1f3e82273bc Cited by: 2 I.V. Sandimirov A.A. Kosov T.A. Vladimirova article Schmid2001347 A 20-km-long seismic line characterises the crustal reflection pattern of the easternmost Dabie Shan, the archetypal ultra-high-pressure (UHP) orogen of eastern China. The weak- to non-reflective upper crust (5 s two-way travel time (TWT); ∼ 15 km depth) is interpreted to comprise UHP rocks thrust over lithologically similar but non-UHP crust. The tectonic contact, although not imaged as a distinct reflector, is probably outlined by the rather abrupt change to diffuse but strong reflectivity within the mid to lower crust. Thus, the seismic pattern of the upper crust implies that mafic, oceanic crust does not constitute a significant proportion. The middle to lower crust (5-10 s TWT; ∼15-33 km depth) probably represents cratonal Yangtze basement, unaffected by the UHP metamorphism. The prominent lowermost reflectors (10-12 s TWT; ∼33-40 km depth) are interpreted to trace the Moho, excluding the presence of a crustal root inherited from the UHP orogeny. A tomographic P-wave velocity model for the uppermost crust (<700 m) traces shallowly W-dipping sedimentary rocks east and UHP gneisses west of the Cenozoic Tan Lu fault which is imaged to dip steeply eastward. The UHP rocks exhibit little lateral and vertical velocity variations (<10%), reflecting grossly homogeneous, gneissic lithology. Hundred-metre-scale velocity variations, however, may trace distinct large-scale structures, e.g. folds, known from outcrops and maps. © 2001 Elsevier Science B.V. All rights reserved. Article 2001 English 00401951 10.1016/S0040-1951(01)00023-3 Tectonophysics 333 347 – 359 3-4 China; crustal structure; deep seismic sounding; seismic tomography; ultrahigh pressure metamorphism https://www.scopus.com/inward/record.uri?eid=2-s2.0-0035014991&doi=10.1016%2fS0040-1951%2801%2900023-3&partnerID=40&md5=6eb6b8fa8ec91f4ffa00f81d210167e2 Cited by: 44 R. Schmid T. Ryberg L. Ratschbacher A. Schulze L. Franz R. Oberhänsli S. Dong article Webb2001231 The Hong'an region offers an unique opportunity to investigate the tectonics of the continental collision event preserved in high-pressure (P) and ultrahigh-P metamorphic rocks in the Qinling-Dabie orogen of eastern China. Here, the extensive Cretaceous tectonic and thermal overprint observed in the Dabie Shan is weak. Normal-sense shear along the north-dipping Huwan detachment zone at the northern edge of the Hong'an block occurred ca. 235 Ma. This detachment facilitated the bulk of the exhumation of the high- and ultrahigh-P rocks as a penetratively deformed slab. The high- and ultrahigh-P rocks are exposed in a warped extensional footwall within which kinematic indicators in the high- and ultrahigh-P units show approximately top-to-north shear. Deformation was accompanied by retrograde metamorphism at amphibolite to greenschist facies conditions. Locally, younger northeast-southwest subhorizontal extension is recorded in ductile to brittle fabrics and the timing of deformation is defined by white mica recrystallization ca. 195 Ma. An Early Cretaceous dextral shear zone along the southwest boundary of the Tongbai Shan was synchronous with plutonism and normal to sinistral-oblique slip along the Xiaotian-Mozitang fault, which forms the northern boundary of the Dabie Shan. Coeval dextral and sinistral shear zones along the southwestern and northern margins of these blocks would have caused eastward lateral extrusion of the Tongbai, Hong'an, and Dabie Shan, perhaps driven by collision of the Lhasa block with Eurasia. Article 2001 English 00721069 10.1130/0-8137-1194-0.231 Memoir of the Geological Society of America 194 Geological Society of America 231 – 245 China; Eurasia; Tongbai Mountains; Deformation; Kinematics; Mica; Tectonics; Continental collisions; Early Cretaceous; High pressure; Kinematic indicators; Lateral extrusion; Qinling-Dabie orogen; Sinistral shear; Ultrahigh pressure rocks; collision; Cretaceous; detachment fold; fault zone; metamorphic rock; phosphate rock; recrystallization; tectonics; Metamorphic rocks https://www.scopus.com/inward/record.uri?eid=2-s2.0-84871183587&doi=10.1130%2f0-8137-1194-0.231&partnerID=40&md5=3a05a95d25d5e43c73893ec85788d258 Cited by: 36 Laura E. Webb Lothar Ratschbacher Bradley R. Hacker Shuwen Dong article Abouchami2000187 We report Pb isotopic compositions for 35 samples of the volcanoes Mauna Loa and Mauna Kea from the Hawaiian Scientific Drilling Project (HSDP-1) core at Hilo. These data were obtained with an external precision of ~ 100 ppm (2σ(ext.)) on the ratios 206Pb/204Pb, 207Pb/204Pb and 208Pb/204Pb by using a Pb triple spike to correct for instrumental mass fractionation. The Pb isotopic compositions in the lower section (1200 to 280 m) of the core sample 200 to 400 ka-old Mauna Kea lavas, and display two well-defined linear arrays in 207Pb/204Pb-206Pb/204Pb and 208Pb/204Pb-206Pb/204Pb isotope spaces. There is a suggestion that Mauna Loa (0 to 280 m depth) also displays such linear array(s). However, analysis of the Mauna Loa samples is complicated by residual contamination and/or sample heterogeneity. While these latter data exhibit a satisfactory array in 208Pb/204Pb vs. 206Pb/204Pb, there still remains scatter in 207Pb/204Pb-206Pb/204Pb space, making it difficult to assess the true Pb isotope systematics of Mauna Loa. The presence of two linear Pb isotopic arrays in Mauna Kea can be interpreted as either reflecting two parallel isochrons or in terms of binary mixing. If interpreted as isochrons, the 207Pb/204Pb-206Pb/204Pb systematics correspond to an age of ~ 1.9 Ga. Comparison of measured Th/U ratios in the lavas and those inferred from Pb isotope systematics strongly suggest that the Pb isotopic arrays reflect binary mixing, and this bears directly on the question of how many distinct components are present in the Hawaiian plume. Most of the new Mauna Kea data lie well outside the mixing-component triangle defined in the literature by the 'Kea', 'Loihi', and 'Koolau' components. On the basis of the relationships between Pb isotope ratios in 3D and a principal component analysis of the Mauna Kea Pb isotope dataset, we show here that a three-component mixing model can in principle explain both mixing lines. However, such an explanation requires a highly specific set of mixing conditions in order to produce parallel arrays in Pb isotope space (2D and 3D). Therefore, our preferred interpretation is that the two arrays reflect binary mixing, with four discrete source components involved in the generation of the Kea lavas. Comparison of the Pb isotope characteristics of these lavas with those of East Pacific Rise (EPR) MORB glasses further suggests that EPR-type Pacific lithosphere does not contribute to the source of Kea lavas. The position of samples along the mixing lines does not correlate with stratigraphic height in the core, and therefore the age of the lavas. Rather, it appears as though the relative proportions of the endmembers are controlled by the spatial configuration of these endmembers, and by melting and transport processes in the source itself. The stratigraphic fluctuations of Pb and Sr isotopes contrast with the monotonic decrease of ε(Nd) and ε(Hf) values as a function of age. This may in part be explained by differences in analytical precision of isotope measurements relative to the total range of values observed. This analytical resolution is far higher for Pb than for the other radiogenic isotopes. Alternatively, the observed fluctuation may be caused by the mobility of lead (as well as Rb and/or Sr) during the ancient differentiation process that created the differences in parent-daughter ratios. (C) 2000 Elsevier Science B.V. All rights reserved. Conference paper 2000 English 00092541 10.1016/S0009-2541(00)00328-4 Chemical Geology 169 187 – 209 1-2 United States; geochemistry; hot spot; lava; lead isotope https://www.scopus.com/inward/record.uri?eid=2-s2.0-0033812173&doi=10.1016%2fS0009-2541%2800%2900328-4&partnerID=40&md5=1e382a010fc6d87bd709e1524d680629 Cited by: 138 W. Abouchami S.J.G. Galer A.W. Hofmann article Xiao20001 The coesite-bearing eclogites and associated ultramafic rocks of Bixiling form the largest metamorphic complex in the Dabie-Sulu ultrahigh-pressure (UHP) metamorphic belt. They mainly consist of 'fresh' eclogite, kyanite-rich eclogite, retrograded eclogite and garnet peridotite. Fluid inclusion and oxygen isotope studies have been carried out on the different types of eclogite and peridotite in order to identify the role of fluids during the metamorphic evolution culminating in UHP metamorphism. Five types of fluid inclusions were distinguished based on textural criteria and fluid compositions: (1) primary Ca-rich brines in quartz blebs in kyanite; (2) primary NaCl-dominated high-salinity inclusions in omphacite and kyanite; (3) primary NaCl-dominated medium- to high-salinity inclusions in matrix quartz; (4) carbonic inclusions in omphacite and matrix quartz; (5) secondary low-salinity aqueous (or pure water) inclusions in matrix quartz. The Ca-rich fluid inclusions in quartz blebs in kyanite represent the earliest recognizable fluids (prograde metamorphism) as they largely escaped late re-equilibration. Fluid inclusions in omphacite and kyanite may have been trapped during peak metamorphic conditions, whereas low-salinity aqueous inclusions in matrix quartz were trapped during the latest stage of uplift. UV-laser oxygen isotope measurements show that garnet and clinopyroxene from the 'fresh' eclogite, kyanite-rich eclogite and garnet peridotite have narrow δ18O values ranging from 3.0 to 3.9‰. In contrast, garnet and omphacite in retrograded eclogite have δ18O values of -1.8 to -1.2 and of -1.1 to -0.6‰, respectively. The difference in oxygen isotope composition is interpreted to result from partial oxygen isotope exchange between the UHP complex and retrograde fluids during late exhumation. Fluids derived from the surrounding gneiss were probably responsible for the low-salinity solutions found in secondary fluid inclusions and the lowering of the δ18O values of the retrograded eclogite. Article 2000 English 00107999 10.1007/s004100050570 Contributions to Mineralogy and Petrology 139 Springer Verlag 1 – 16 1 Bixiling; China; Dabie Shan; coesite; eclogite; fluid composition; fluid inclusion; isotopic composition; oxygen; ultrahigh pressure metamorphism https://www.scopus.com/inward/record.uri?eid=2-s2.0-0033846390&doi=10.1007%2fs004100050570&partnerID=40&md5=61367e886f699c5d1b2214f1339bdffa Cited by: 164 Yilin Xiao Jochen Hoefs Alfons M. Van Den Kerkhof Jens Fiebig Yongfei Zheng article Mikami20001011 Core samples containing pore-spare gas hydrate within granular sands were collected from 913.76 m of the research well named JAPEX/JNOC/GSC Mallik 2L-38. X-ray CT images of the core were acquired while warming from -18 to 4°C, and subsequently during stepped decreases of 0.1 MPa in the chamber pressure below the methane hydrate equilibrium pressure. Discharged gas flows and sample temperatures were monitored continuously. Changes in CT values indicated that gas hydrate dissociated simultaneously both on the exposed surfaces and within the pore spaces of the sample in response to pressure changes. This suggested that pressure reductions were effectively transmitted through the sample most likely because the samples contained some amount of fluids. The result of gas flow measurements indicated that a larger pressure drawdown caused a higher dissociation rate. 2000 English 00778923 10.1111/j.1749-6632.2000.tb06856.x Annals of the New York Academy of Sciences 912 New York Academy of Sciences 1011-1020 JAPEX Research Center, 1-2-1 Hamada, Mihama-ku, Chiba 261-0025, Japan; Department of Geosystem Engineering, University of Tokyo, 7-3-1 Hongou, Bunkyo-ku, Tokyo 113-8656, Japan; Teikoku Oil Company, 1-31-10 Hatagaya, Shibuya-ku, Tokyo 151-0072, Japan methane; natural gas, computer assisted tomography; conference paper; dissociation; gas; gas flow; pressure; sand; temperature; X ray analysis https://www.scopus.com/inward/record.uri?eid=2-s2.0-0033926433&doi=10.1111%2fj.1749-6632.2000.tb06856.x&partnerID=40&md5=75b1e302735ab2088623d389bab36185 cited By 21 J. Mikami Y. Masuda T. Uchida T. Satoh H. Takeda article Cross200021 New evidence from piston cores and high-resolution seismic reflection data shows that water levels in Lake Titicaca were as much as 100 m below the present level during the early to mid-Holocene (between >6 and 3.8 14C kyr BP). Climatological and modelling studies indicate that Lake Titicaca rainfall depends on convective activity in upwind Amazonia; the lake-level data therefore suggest a drier Amazon Basin during this time. This view is bolstered by an excellent match between the Titicaca lake-level curve and decreased methane concentrations in Greenland ice, previously ascribed to drying of low-latitude wetlands (Blunier et al., 1995). The postglacial history of Lake Titicaca fits a global pattern of lake-level change in the tropics, characterized by opposite phasing between the Southern and Northern Hemispheres. This pattern is most likely the result of orbital controls over the intensity of summer insolation. Article 2000 10.1191/095968300671452546 Holocene 10 21 – 32 1 Bolivia; Lake Titicaca; Holocene; lake level; lowstand; paleohydrology https://www.scopus.com/inward/record.uri?eid=2-s2.0-0033980356&doi=10.1191%2f095968300671452546&partnerID=40&md5=31df638cd72a5522f79d5bd09634935a Cited by: 136 Scott L. Cross Paul A. Baker Geoffrey O. Seltzer Sherilyn C. Fritz Robert B. Dunbar article Phedorin2000400 The paper presents a comparison of the profiles of biogenic silica (BiSi), Br and Nd in the first 20 m of the BDP-96-2 core of sediments of Lake Baikal obtained on top of the underwater Akademichesky Ridge. The concentrations of the two elements mentioned were measured by X-ray fluorescent analysis with synchrotron radiation (SR-XFA) at 10 cm intervals. Br correlates positively, and Nd negatively with BiSi. Spectral analysis of the profiles revealed the 100, 41, 23 and 19 kyr major external forcing periods. We studied the elemental composition of extant diatom algae of Lake Baikal in order to find out whether any elements are bound by them specifically. SR-XFA revealed, among others that Br is accumulated by extant diatom algae of Lake Baikal, presumably due to incorporation into their organic matter. Br can be regarded as a new proxy of the paleo-productivity of Lake Baikal. The paper also considers arguments suggesting that the first 2 m of sediment are missing in the BDP-96-2 core. Article 2000 English 01689002 10.1016/S0168-9002(99)00726-3 Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 448 Elsevier Science B.V. 400 – 406 1 Bromine; Geochemistry; Lakes; Neodymium; Organic compounds; Sediments; Silica; Spectrum analysis; Synchrotron radiation; Biogenic silica; Lake Baikal; Paleoclimate indicators; Sedimentary geochemistry; X ray fluorescence analysis; X ray analysis https://www.scopus.com/inward/record.uri?eid=2-s2.0-0034207522&doi=10.1016%2fS0168-9002%2899%2900726-3&partnerID=40&md5=c7f1762c2524052ef24e31c7a6caa13c Cited by: 37 M.A. Phedorin E.L. Goldberg M.A. Grachev O.L. Levina O.M. Khlystov I.P. Dolbnya article Horiuchi2000562 Sedimentary 10Be records covering the last 150 kyr were obtained from three cores collected at the Academician Ridge (BDP-96/hole2 core and VER96/st.3 core) and at the Buguldeika Saddle (BDP-93/hole2 core) in Lake Baikal. The 10Be concentrations of the three cores varied between 0.5 × 109 and 1.5 × 109 atoms/g, and coincidently dropped at the stratigraphic intervals of marine oxygen isotope stages (MIS) 2, 4, 5d and 6. The depositional fluxes of 10Be, on the other hand, generally rose in those stages having an increase in the dry bulk densities and sediment accumulation rates. These results are consistent with previous work (Horiuchi et al., 1999), suggesting that the dilution effects of low-10Beconcentration particles principally controlled the fluctuations of the 10Be concentrations of Lake Baikal sediments. Low-10Be-concentration particles have been intensively produced by mechanical weathering and physical erosion under the cold and dry climatic conditions during the peak glaciation period, and have been directly brought from the source areas into the lake as a result of the thin vegetative cover of the watershed. © 2000 Elsevier Science B.V. All rights reserved. Article 2000 English 0168583X 10.1016/S0168-583X(00)00100-2 Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms 172 Elsevier 562 – 567 1-4 Beryllium; Climate change; Erosion; Glacial geology; Lakes; Oxygen; Radioisotopes; Sediments; Stratigraphy; Watersheds; Weathering; Accelerated mass spectrometry; Marine oxygen isotope stages; Marine sediments; Mass spectrometry https://www.scopus.com/inward/record.uri?eid=2-s2.0-0034290749&doi=10.1016%2fS0168-583X%2800%2900100-2&partnerID=40&md5=b696d7616dbe29eeb4c90e7f21c87a99 Cited by: 7 K. Horiuchi K. Kobayashi T. Oda T. Nakamura C. Fujimura H. Matsuzaki Y. Shibata article Kuzmin20001347 The mineral assemblage of Pliocene - Pleistocene bottom sediments of Lake Baikal, exposed by the deep-sea BDP-96-2 (Baikal Drilling Project) has been studied by the methods of XRD and IR spectroscopy. Complex XRD patterns of clay minerals have been modeled using an advanced algorithm based on calculation of interference function from one-dimensional disordered crystals of finite thickness. The modeling implies fitting of theoretical to observed patterns and optimization procedure by methods of nonlinear programming. It has been shown that major clay minerals in the sediments that formed for the past 2.5 Ma during cold stages are illite-illite-smectites with predominantly illite layers, and chlorite; the principal clay minerals in the sediments that formed during warm periods are smectite, illite-smectites with high contents of smectite layers, and chlorite-smectites. These data allow unravelling the climate history of Lake Baikal from biogenic silica record. Article 2000 Russian 00167886 Geologiya i Geofizika 41 1347 – 1359 10 https://www.scopus.com/inward/record.uri?eid=2-s2.0-0000839938&partnerID=40&md5=ff295adc72870ab812aa0e1aee1716d0 Cited by: 5 M.I. Kuz'min E.P. Solotchina A.N. Vasilevskii V.N. Stolpovskaya E.B. Karabanov V.F. Geletii V.A. Bychinskii G.N. Anoshin S.G. Shul'zhenko article Karabanov2000211 Article 2000 10.1016/S0031-0182(99)00141-8 Palaeogeography, Palaeoclimatology, Palaeoecology 156 211 – 224 3-4 https://www.scopus.com/inward/record.uri?eid=2-s2.0-0034161734&doi=10.1016%2fS0031-0182%2899%2900141-8&partnerID=40&md5=f1a572e3a37d5b56659d3935fceeaca6 Cited by: 77 E.B. Karabanov A.A. Prokopenko D.F. Williams G.K. Khursevich article Ohara2000733 The Mallik 2L-38 well was drilled in February and March, 1998 to a depth of 1150m at a site located in the Mackenzie Delta, N. W. T., Canada. Undertaken as a collaborative agreement between the Japan National Oil Corporation and the Geological Survey of Canada, the well was conducted as a research and development project with engineering goals to evaluate various technologies for drilling and coring gas-hydrate-bearing strata. The Mallik site was chosen as it had favorable logistics and was though to contain a thick interval of gas hydrates between 897 and 1110 m depth. Drilling operation included a surface hole (with 8 coring runs) to 687m for installation of a 340mm surface casing, and a main hole (with 16 coring runs) to the target depth of 1150m. The drilling system utilized a KCl/polymer drilling mud that was cooled to 2°C using a plate type heat exchanger. Drilltreat, a chemical mud additive was used in the main hole to stabilize the hydrate within drill cuttings and formation sediments. Drilling operations were conducted without any serious hole problems, accidents, or mishaps. However, delays were caused by adverse weather and mechanical problems, causing adjustments in the overall program. Coring in the main hole was particularly successful allowing evaluation of four different core barrels. Gas-hydrate-bearing core was collected in a variety of sediments between 886 and 952m. The excellent condition of the core samples, controlled gas hydrate dissociation within the mud column, and near-gauge hole, confirmed that the combination of chilled mud with Drilltreat performed extremity well. 2000 English 9781555633493 10.2523/59795-ms SPE Proceedings - Gas Technology Symposium Soc Pet Eng (SPE), Richardson 733-742 Japan Petroleum Exploration Co, Ltd, Japan Additives; Gas hydrates; Heat exchangers; Mud logging; Natural gas well drilling; Oil field development; Organic polymers; Petroleum industry; Petroleum prospecting; Potassium compounds; Sediments; Societies and institutions, Chemical mud additive; Coring; Coring gas hydrate bearing strata; Polymer drilling mud; Potassium chloride drilling mud, Natural gas fields https://www.scopus.com/inward/record.uri?eid=2-s2.0-0033688165&doi=10.2523%2f59795-ms&partnerID=40&md5=edb43bb0a8093b0ca4a366f802b15bb2 cited By 8 T. Ohara S.R. Dallimore E. Fercho incollection TAKAHARA2000108 2000 978-0-444-50434-0 https://doi.org/10.1016/B978-044450434-0/50010-X Lake Baikal Elsevier Science B.V.

Amsterdam

Koji Minoura 108-118 https://www.sciencedirect.com/science/article/pii/B978044450434050010X H. Takahara S.K. Krivonogov E.V. Bezrukova N. Miyoshi Y. Morita T. Nakamura Y. Hase Y Shinomiya K. Kawamuro article Schmid2000185 A suite of coesite-eclogites and associated calc-silicate rocks from the ultra-high-pressure (UHP) belt in the Dabie Shan (eastern China) was investigated petrologically. Field relations and the presence of UHP minerals such as coesite, omphacite and high-Si phengite in the eclogites and the enclosing calc-silicates testify to a common metamorphic evolution for these two lithologies. Except for one sample, all bear phengite with unusually high silica contents (Si up to 3.7 per formula unit). Phengite occupies various textural positions indicating that different metamorphic stages are reflected by these white micas, which correlate with distinct mineral zonation patterns. Using the latest thermobarometric calibrations for eclogite-facies rocks, maximum pressure-temperature (P-T) conditions of 40-48 kbar at < 750°C were estimated for the peak-metamorphic mineral assemblages. These P-T conditions were calculated for both eclogitic garnet porphyroblasts with diffusion-controlled zoning as well as garnet porphyroblasts with prograde growth zonation patterns. Most samples were affected by a strong retrograde overprint mainly under eclogite- and amphibolite-facies conditions. Thermobarometry using mineral sets from different textural positions reveals cooling and decompression of the UHP rocks down to < 20 kbar at < 600°C for the bulk of the samples. Decompression and heating indicated by a few samples is interpreted to result from mineral chemical disequilibrium or late thermal influence. These new data show that subduction of continental crust in the Dabie Shan was deeper than previously thought, and also that some cooling and decompression took place at upper-mantle depths. Copyright © 2000 John Wiley and Sons, Ltd. Article 2000 English 00721050 10.1002/gj.863 Geological Journal 35 John Wiley and Sons Ltd 185 – 207 3-4 China; Dabie Shan; eclogite; metamorphism; P-T conditions; ultrahigh pressure metamorphism https://www.scopus.com/inward/record.uri?eid=2-s2.0-0034450350&doi=10.1002%2fgj.863&partnerID=40&md5=c0799a09bb4fbd53ef24c8013461bd32 Cited by: 50 Robert Schmid Leander Franz Roland Oberhnsli Shuwen Dong article Holcomb2000547 The submarine Hilo Ridge has been interpreted as a part of Mauna Kea volcano, but is crossed at ~1100 m depth by a submerged shoreline terrace composed of basalts that are isotopically distinct from those of Mauna Kea and similar to those of Kohala volcano. This terrace evidently is a product of Kohala instead of Mauna Kea. Almost all of Hilo Ridge below the terrace therefore must predate the principal growth of Mauna Kea, which has superficially isolated the ridge from its Kohala source by overlapping its proximal segment. The Mauna Kea section penetrated by the Hawaii Scientific Drilling Project is predicted to be thinner than expected previously, owing to the overlap. Similar overlaps are suspected among other volcanoes and may cause significant changes in the understanding of Hawaiian volcanism. Article 2000 English 19432682 10.1130/0091-7613(2000)28<547:OVTOOH>2.0.CO;2 Geology 28 Geological Society of America 547 – 550 6 Hawaii [(ISL) Hawaiian Islands]; Hawaii [United States]; Hawaiian Islands; Hilo; Kohala; Mauna Kea; United States; Isotopes; Hilo Ridge; Isotope ratios; Kohala; Mauna Kea; Scientific drilling; isotopic ratio; shoreline; submarine; terrace; volcanism; volcano; Volcanoes https://www.scopus.com/inward/record.uri?eid=2-s2.0-0034432407&doi=10.1130%2f0091-7613%282000%2928%3c547%3aOVTOOH%3e2.0.CO%3b2&partnerID=40&md5=a561bc902e13bff6ac2c279c99c9711f Cited by: 29 Robin T. Holcomb Bruce K. Nelson Peter W. Reiners Nuni-Lyn Sawyer article Li2000938 The volcanic edifice of the Hawaiian islands and seamounts, as well as the surrounding area of shallow sea floor known as the Hawaiian swell, are believed to result from the passage of the oceanic lithosphere over a mantle hotspot. Although geochemical and gravity observations indicate the existence of a mantle thermal plume beneath Hawaii, no direct seismic evidence for such a plume in the upper mantle has yet been found. Here we present an analysis of compressional-to-shear (P-to-S) converted seismic phases, recorded on seismograph stations on the Hawaiian islands, that indicate a zone of very low shear-wave velocity (&lt; 4 km s-1) starting at 130-140 km depth beneath the central part of the island of Hawaii and extending deeper into the upper mantle. We also find that the upper-mantle transition zone (410-660 km depth) appears to be thinned by up to 40-50 km to the south-southwest of the island of Hawaii. We interpret these observations as localized effects of the Hawaiian plume conduit in the asthenosphere and mantle transition zone with excess temperature of ~300°C. Large variations in the transition-zone thickness suggest a lower-mantle origin of the Hawaiian plume similar to the Iceland plume, but our results indicate a 100°C higher temperature for the Hawaiian plume. 2000 English 00280836 10.1038/35016054 Nature 405 938-941 GeoForschungsZentrum Potsdam, Telegrafenberg, 14473 Potsdam, Germany; Freie Universität, FR Geophysik, Malteserstr. 74-100, 12249 Berlin, Germany; Bullard Laboratories, Department of Earth Sciences, University of Cambridge, Cambridge CB3 0EZ, United Kingdom; Universität Potsdam, Institut für Geowissenschaften, Postfach 601553, 14415 Potsdam, Germany 6789 crustal structure; hot spot; mantle plume; seismic velocity, air temperature; article; atmosphere; geography; plume; priority journal; sea; shear rate; United States; volcano, Pacific Ocean https://www.scopus.com/inward/record.uri?eid=2-s2.0-0034702189&doi=10.1038%2f35016054&partnerID=40&md5=ca20b23fc1d932fdee5853ea4bfc0cef cited By 172 X. Li R. Kind K. Priestloy S.V. Sobolev F. Tilmann X. Yuar M. Weber article Phedorin2000217 A new technique for the determination of uranium and thorium in lacustrine sediments is based on non-destructive synchrotron radiation X-ray fluorescence analysis (SR-XRF) of sediment samples using monochromatic beams of different energies as excitation sources, with the recording and subsequent iterative processing of the X-ray fluorescence spectra. The technique has a multielement capability and enables fast, simultaneous analysis of a few tens of elements. The proposed SR-XRF technique was tested against INAA and ICP-MS methods and showed a number of advantages with a generally good correlation of results by the three methods. Uranium and Th profiles have been measured at a time resolution of 2 kyr in a drill core (BDP-96) from Lake Baikal bottom sediments deposited between 780 and 40 kyr BP. During this time span, peaks in the U and U/Th concentration marked "warm" climates. Oscillations of U and U/Th in Baikal bottom sediments during the Brunhes chron reflect climate-induced global change in the volume of polar ice, controlled by long-term cyclicity of the Earth's orbital parameters. The response of these "warm" periods is similar to that observed earlier in shorter cores that span the two last interglacials (220-0 kyr BP). Review 2000 English 01505505 10.1111/j.1751-908X.2000.tb00773.x Geostandards Newsletter 24 217 – 226 2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-33745133660&doi=10.1111%2fj.1751-908X.2000.tb00773.x&partnerID=40&md5=308d9ba7884b1c69f2928f479a451375 Cited by: 7 Michael A. Phedorin Evgeny L. Goldberg Vladislav A. Bobrov Oleg M. Khlystov Michael A. Grachev article Nakamura20009 The purpose of this study is to learn how to consider setting the borehole and arrangement of the measuring instruments for seismic tomography. For this purpose we made an underground structure model of Unzen Volcano based on the results of previous studies, and simulated the seismic tomography identifying this model with the true structure because one of some plans in "Scientific drilling project at Unzen Volcano" is seismic tomography by using a borehole approaching conduit" We located sources and receivers along the borehole and at the surface, and calculated synthetic seismograms at the receiver positions by a 2-D finite difference method. We measured the first P arrival time in the synthetic seismograms, and constructed the observational equation for seismic tomography. We investigated the solution of this equation by the Singular Value Decomposition (SVD) technique. We found we can consider borehole location and arrangement of sources and receivers through such a simulation by Singular values and eigenvalue that got in this way. 2000 Japanese 13480545 Science Reports of the Kyushu University, Department of Earth and Planetary Sciences 21 9-18 1 array; crosshole seismic method; seismic tomography https://www.scopus.com/inward/record.uri?eid=2-s2.0-13844276804&partnerID=40&md5=9d0974859a0f4531f0e6f1b20fd7f528 cited By 0 M. Nakamura T. Hayashida H. Takenaka H. Shimizu S. Suzuki article Uchida20001021 The JAPEX/JNOC/GSC Mallik 2L-38 research well was drilled to a depth of 1150 m beneath the permafrost zone in the Mackenzie Delta, N.W.T., Canada, early in 1998. A large amount of natural gas hydrates were successfully retrieved from a variety of sandy and gravel sediments. Over 110 m of gas hydrate-bearing sediments were found to be distributed between 897 m and 1100 m deep. Approximately 37 meters of core were recovered in this interval with most of the recovered gas hydrates being less than 2 mm in size occurring mainly in intergranular porosity of silty to clean massive sand and conglomerate (granule to pebble). Typically, hydrate-bearing strata were between 10 cm and more than one meter thick with an estimated porosity of 25 to 35%. The largest form of hydrate was about 2 cm in diameter, occurring as clasts and intergranular porosity within granular sands. Occurrences of natural gas hydrate have been observed visually at the drill site and in core samples preserved in pressurized storage vessels utilizing an X-ray CT scanner technique. Quantitative assessments of gas hydrate concentrations in core samples have been made based on pressure response of dissociation vessels and direct volumetric measurements. Six types of gas hydrate have been recognized: (1) pore-space hydrate, (2) platy hydrate, (3) layered/massive hydrate, (4) disseminated hydrate, (5) nodule hydrate, and (6) vein/dyke hydrate. The X-ray CT images proved useful for characterizing macroscopic forms of gas hydrate. Finer grained occurrences were more difficult to study, however the distribution of gas hydrates and granular grains ran be recognized. The occurrences of natural gas hydrates in the Mallik well are compared to the previous natural gas hydrate core samples obtained from ODP/DSDP programs and other field studies. 2000 English 00778923 10.1111/j.1749-6632.2000.tb06857.x Annals of the New York Academy of Sciences 912 New York Academy of Sciences 1021-1033 JAPEX Research Center, 1-2-1 Hamada, Mihama, Chiba 261-0025, Japan; Geologicai Survey of Canada, 601 Booth Street, Ottawa, Ont. K1A 0E8, Canada methane; natural gas, Canada; computer assisted tomography; conference paper; gas; gas analysis; oil industry; porosity; sand; sediment; X ray analysis https://www.scopus.com/inward/record.uri?eid=2-s2.0-0033941353&doi=10.1111%2fj.1749-6632.2000.tb06857.x&partnerID=40&md5=27d7994047bfa60edc0ae655ef3c73bc cited By 34 T. Uchida S. Dallimore J. Mikami article Sobolev2000986 The hypothesis that mantle plumes contain recycled oceanic crust is now widely accepted. Some specific source components of the Hawaiian plume have been inferred to represent recycled oceanic basalts, pelagic sediments or oceanic gabbros. Bulk lava compositions, however, retain the specific trace- element fingerprint of the original crustal component in only a highly attenuated form. Here we report the discovery of exotic, strontium-enriched melt inclusions in Mauna Loa olivines. Their complete trace-element patterns strongly resemble those of layered gabbros found in ophiolites, which are characterized by cumulus plagioclase with very high strontium abundances. The major-element compositions of these melts indicate that their composition cannot be the result of the assimilation of present-day oceanic crust through which the melts have travelled. Instead, the gabbro has been transformed into a (high-pressure) eclogite by subduction and recycling, and this eclogite has then been incorporated into the Hawaiian mantle plume. The trace-element signature of the original plagioclase is present only as a 'ghost' signature, which permits specific identification of the recycled rock type. The 'ghost plagioclase' trace-element signature demonstrates that the former gabbro can retain much of its original chemical identity through the convective cycle without completely mixing with other portions of the former oceanic crust. 2000 English 00280836 10.1038/35010098 Nature 404 986-990 Max-Planck-Institut für Chemie, Postfach 3060, 55020 Mainz, Germany; Vernadsky Institute of Geochemistry, Russian Academy of Sciences, Kosygin Street 19, 117975 Moscow, Russian Federation; Department of Petrology, Vrije Universiteit, De Boelelaan 1085, 1081 HV, Amsterdam, Netherlands 6781 basalt; mantle plume; melt inclusion; oceanic crust; petrogenesis; petrology; recycling; strontium, article; geography; geology; natural science; oceanic regions; priority journal; United States; volcano, United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-0034720222&doi=10.1038%2f35010098&partnerID=40&md5=05e67efe2c21265184468079798f780c cited By 300 A.V. Sobolev A.W. Hofmann I.K. Nikogosian article Winters200094 As part of an interdisciplinary field program, a 1150-m deep well was drilled in the Canadian Arctic to determine, among other goals, the location, characteristics, and properties of gas hydrate. Numerous physical properties of the host sediment were measured in the laboratory and are presented in relation to the lithology and quantity of in situ gas hydrate. Profiles of measured and derived properties presented from that investigation include: sediment wet bulk density, water content, porosity, grain density, salinity, gas hydrate content (percent occupancy of non-sediment grain void space), grain size, porosity, and post-recovery core temperature. The greatest concentration of gas hydrate is located within sand and gravel deposits between 897 and 922 m. Silty sediment between 926 and 952 m contained substantially less, or no, gas hydrate perhaps because of smaller pore size. 2000 English 00778923 10.1111/j.1749-6632.2000.tb06762.x Annals of the New York Academy of Sciences 912 New York Academy of Sciences 94-100 U.S. Geological Survey, 384 Woods Hole Road, Woods Hole, MA 02543, United States; Geological Survey of Canada, Ottawa, Ont. K1A 0E8, Canada; U.S. Geological Survey, Denver, CO 25046, United States; Geological Survey of Canada, Dartmouth, NS B2Y 4A2, Canada; Japan Petroleum Exploration Company, Mihama-ku Chiba, Japan methane; natural gas, Arctic; Canada; conference paper; gas; gas analysis; porosity; river; salinity; sand; sediment; temperature; water content https://www.scopus.com/inward/record.uri?eid=2-s2.0-0033940146&doi=10.1111%2fj.1749-6632.2000.tb06762.x&partnerID=40&md5=15bb2c4b8ec3a1b40a0b1f9de5e11297 cited By 9 W.J. Winters S.R. Dallimore T.S. Collett K.A. Jenner J.T. Katsube R.E. Cranston J.F. Wright F.M. Nixon T. Uchida article Hyde20001347 In conjunction with the 1998 Mallik 2L-38 gas-hydrate research well program (Dallimore et al, 1999), two time-domain electromagnetic sounding profiles were surveyed in an attempt to delineate a known gas-hydrate zone at depth. The research well is located on Richard's Island in the Mackenzie Delta, Northwest Territories. Electrical resistivity logging at the Mallik site in 1972 and 1998 defined a resistive zone from 900 m to 1100 m coincident with a gas-hydrate zone lying within unfrozen and electrically conductive sediments. A resistive layer, interpreted as the gas-hydrate zone was detected by the TEM survey at all soundings except for those overlain by thin permafrost and a thick unfrozen zone. This thin permafrost/thick unfrozen zone assemblage resulted in greater than expected conductivity-thickness product and limited the depth investigation of the survey. In addition, late-time negative transients interpreted as induced polarization effects, obscured the clear detection of gas hydrates. © 2000 Society of Exploration Geophysicists. 2000 English 10523812 10.1190/1.1815647 SEG Technical Program Expanded Abstracts 19 Society of Exploration Geophysicists 1347-1350 Terrain Sciences, Geological Survey of Canada, Canada 1 Electric logging; Gases; Hydration; Permafrost; Petroleum prospecting; Surveys, Electrically conductive; Hydrate zones; Induced polarization; Resistive zones; TEM surveys; Time domain electromagnetics, Gas hydrates https://www.scopus.com/inward/record.uri?eid=2-s2.0-84955067779&doi=10.1190%2f1.1815647&partnerID=40&md5=2dd2d5b00c910d3138883dab6bf6e7e3 cited By 0 C. Hyde S. Dallimore J. Hunter M. Douma R. Good R. Burns article Kuzmin2000183 With this paper we present a first attempt to combine the direct results on lithology, composition and age dating in the boreholes BDP-93, BDP-96 and BDP-97 with geological and seismic data from the areas where those sections were drilled. The sedimentary environments represented by the BDP boreholes are markedly different and possess characteristic lithological features. The results of the deep drilling provide the essential means for testing numerous age models used in geological reconstructions of the Lake Baikal rifting dynamics. Neither the basin-wide unconformity interpreted from seismic data, nor the interpreted change from shallow-water to deep-water facies at the boundary of the seismic stratigraphic complexes were found in the BDP-96 boreholes on Academician Ridge. Also, lithology does not support the proposed reconstructions of intense lake level fluctuations and transgressions during the Pliocene at Academician Ridge. The continuous deep-water hemipelagic sedimentation at Academician Ridge has existed for the past 5 Ma. The beginning of an intense rifting phase of the Neobaikalian sub-stage and related drastic changes in sedimentation processes were interpreted on seismic sections as the basin-wide unconformity B10. Different age estimates for this boundary ranged from Late Pliocene (3.5 Ma) to Plio-Pleistocene boundary. As shown by BDP-96 borehole, B10 is associated with a lithological change from diatomaceous ooze to dense silty clay and not with an erosional contact. The new age for this boundary in BDP-96 is approximately 2.5 Ma. This new age constraint suggests that the upper sedimentary strata of Northern Baikal (1.5-1.7 km thick) have formed during the past 2.5 Ma with average sedimentation rates of 60-70 cm/ka. The BDP-93 boreholes at Buguldeika suggest that uplift in Primorsky Range took place prior to 1.07-1.31 Ma, a date which exceeds the age of previous geological models. Article 2000 English 14373254 10.1007/s005310000090 International Journal of Earth Sciences 89 183 – 192 2 Russian Federation; depositional environment; paleoclimate; paleoenvironment; Pliocene; Quaternary; rifting; sedimentation rate https://www.scopus.com/inward/record.uri?eid=2-s2.0-0033792304&doi=10.1007%2fs005310000090&partnerID=40&md5=fa8d153190b05820a1c651fbda7272dd Cited by: 53 M.I. Kuzmin E.B. Karabanov A.A. Prokopenko V.F. Gelety V.S. Antipin D.F. Williams A.N. Gvozdkov article Tulk2000859 Raman spectroscopy is reviewed with particular emphasis placed on its application to gas hydrates. Experimental examples discussed include studies of the totally symmetric C-H stretching vibration v1 (A1) of methane in both synthetic and natural hydrate samples (from the JAPEX/JNOC/GSC Mallik 2L-38 research well); a comparison of the coupled O-H vibrations of water in the host lattice of CH4 hydrate and ice I(h) at low temperature; and local structural details of the relaxation of the hydrogen-bonded water on crystallization to structure II hydrate of amorphous tetrahydrofuran (THF) aqueous solutions. This paper is intended to be an introduction to Raman spectroscopy with specific examples from research at the National Research Council of Canada, and is aimed at those who wish to apply the technique as a tool to investigate gas hydrates. 2000 English 00778923 10.1111/j.1749-6632.2000.tb06840.x Annals of the New York Academy of Sciences 912 New York Academy of Sciences 859-872 Steacie Inst. for Molecular Sciences, National Research Council of Canada, Ottawa, Ont. K1A 0R6, Canada methane; water, aqueous solution; conference paper; crystallization; gas; gas analysis; Raman spectrometry https://www.scopus.com/inward/record.uri?eid=2-s2.0-0033941607&doi=10.1111%2fj.1749-6632.2000.tb06840.x&partnerID=40&md5=0e64a32a74bfdcc07d2787ee755f0d47 cited By 86 C.A. Tulk J.A. Ripmeester D.D. Klug article Roeloffs20001226 The US Geological Survey, in cooperation with other institutions, continues to monitor the San Andreas Fault (SAF) near Parkfield, California, hoping to capture high resolution records of continuous deformation before, during and after a magnitude 6 earthquake, as well as the details of its rupture initiation and strong ground motion. Despite the failure of the prediction that the next M 6 Parkfield earthquake would occur before 1993, Parkfield still has a higher known probability (1 to 10% per year) than anywhere else in the US of a M 6 or greater earthquake. Parkfield instrumentation is still largely in place, although there have been losses due to attrition as well as improvements made possible by new technology. Most Parkfield data sets are now available via the Internet, and all others may be obtained upon request from individual investigators. Detailed seismic monitoring has shown that events with identical seismograms, recurring in exactly the same locations, account for a high proportion of the background seismicity at Parkfield. Geophysical studies have revealed that fault zone seismic and electrical properties are consistent with high fluid content. The rate of interseismic slip on the SAF changed significantly in late 1992 or early 1993, during a period of relatively high seismic activity. The strain-rate change, measured by borehole tensor strainmeters and the two-colour electronic distance-measuring network, was also manifested as shortened recurrence intervals of repeating microearthquakes. Whether or not the accelerated deformation turns out to be an intermediate-term precursor to the next M 6 Parkfield earthquake, documenting the variation of interseismic strain rates with time has important implications for fault dynamics and seismic hazard estimation. Two possible instances of pre-earthquake signals have been recorded at Parkfield: water-level and strain changes over a period of three days prior to the nearby 1985 Mw 6.1 Kettleman Hills, California, earthquake and anomalous electromagnetic signals prior to the M 5 earthquake near Parkfield on 20 December 1994. Future work planned at Parkfield includes a National Science Foundation proposal to construct an SAF Observatory at Depth (SAFOD), as part of the Earthscope initiative. The Observatory will consist of a 4-km-deep borehole to penetrate the SAF and a shallow microearthquake cluster on Middle Mountain, directly above the hypocenter of the 1966 Parkfield earthquake. 2000 English 00113891 Current Science 79 1226-1236 US Geological Survey, 5400 MacArthur Blvd., Vancouver, WA 98661, United States 9 https://www.scopus.com/inward/record.uri?eid=2-s2.0-0010383618&partnerID=40&md5=2e48052b9901f718e8a2291ab4dc3091 cited By 28 E. Roeloffs article Rebolledo-Vleyra2000928 A scientific drilling program is being carried out by the National Autonomous University of Mexico (UNAM) at the southern sector of the Chicxulub impact crater in the Yucatan Peninsula, Mexico. Eight boreholes, ranging in depth from 60 m to 702 m, with a total of 2.62 km of continuos core, were recovered. A high recovery rate of up to 99% (overall average recovery rate for the eight boreholes is 87%) allows us to investigate in detail the stratigraphy of the impact lithologies and the Tertiary carbonate sequence. Three of the boreholes (UNAM-5, UNAM-6, and UNAM-7, with core recovery rates from 89 to 99%) sampled impact breccias that were classified in two units-an upper breccia sequence rich in basement clasts, impact glass, and fragments of melt (suevite-like breccia) and a lower breccia sequence rich in limestone, dolomite, and evaporite clasts (bunte-like breccia). Depths of contact between the Tertiary carbonate sequence and the impact breccias are 332.0 m in UNAM-5, 222.2 m in UNAM-7, and 282.8 m in UNAM-6, giving the depth to the K/T boundary. In UNAM-7, the contact between the upper and the lower breccias is at 348.4 m, which yields a thickness of 126.2 m for the suevite-like breccia. The rest of the boreholes sampled part of the Tertiary carbonate sequence (∼200 m thick), composed mainly of limestones, dolomitized carbonates, and calcarenite, with some fossiliferous horizons. 2000 10.1080/00206810009465118 International Geology Review 42 928-940 Laboratorio de Paleomagnetismo y Geofisica Nuclear, Instituto de Geofisica, Universidad National Autonoma de Mexico, Coyoacán, D.F., 04510, Mexico; Institute of Geophysics, University of Alaska, Fairbanks AK 903 Koyukuk Dr, United States 10 https://www.scopus.com/inward/record.uri?eid=2-s2.0-0034477630&doi=10.1080%2f00206810009465118&partnerID=40&md5=73ea08396e74dd35779d7d9f99424809 cited By 50 M. Rebolledo-Vleyra J. Urrutia-Fucugauchi L.E. Marín A. Trejo-García V.L. Sharpton A.M. Soler-Arechalde incollection J200090 2000 978-0-444-50434-0 https://doi.org/10.1016/B978-044450434-0/50008-1 Lake Baikal Elsevier Science B.V.

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Koji Minoura 90-100 https://www.sciencedirect.com/science/article/pii/B9780444504340500081 J. Müller J. Kasbohm H. Oberhänsli M. Melles H.W. Hubberten incollection KAWAMURO2000101 2000 978-0-444-50434-0 https://doi.org/10.1016/B978-044450434-0/50009-3 Lake Baikal Elsevier Science B.V.

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Koji Minoura 101-107 https://www.sciencedirect.com/science/article/pii/B9780444504340500093 K. Kawamuro K. Shichi Y. Hase A. Iwauchi K. Minoura T. Oda H. Takahara H. Sakai Y. Morita N. Miyoshi M.I. Kuzmin article Lee2000179 One of the distinct physical properties of gas-hydrate-bearing sediments is elevated seismic velocities. A number of velocity models and equations have been presented to describe the effect of gas hydrate on the seismic velocities; e.g., pore-filling model, cementation model, effective medium theory, a weighted equation, and time-average equation. The data set from Mallik 2L-38 gas hydrate research well drilled in northern Canada provided us a unique opportunity to test the velocity models for gas-hydrate-bearing sediments. Velocities predicted from an effective medium theory and those from a weighted equation are compared with observed well log velocities. In the case where there is no gas hydrate in the pore space, P-wave velocities predicted from the effective medium theory are lower than those from the weighted equation when porosity is less than about 30% and higher when porosity is higher than about 30%. For S-waves, effective medium theory predicts generally higher velocities than those from the weighted equation. Both theories predict similar increases in P- and S-wave velocities when gas hydrate occupies the pore space. Even though gas hydrate concentration in the pore space is not known accurately, analyses using both P- and S-wave velocities and their ratios enable us to test the validity of velocity models. Considering only P-wave velocities, there is not much difference between the effective medium and weighted equation. However, considering both P- and S-wave velocities and their ratios, the weighted equation is preferred to the effective medium theory in predicting elastic wave velocities for gas-hydrate-bearing sediments at the Mallik 2L-38 well. © 2001 by the American Geophysical Union. 2000 English 9781118668412; 9780875909820 00658448 10.1029/GM124p0179 Geophysical Monograph Series 124 Blackwell Publishing Ltd Dillon W.P., Paull C.K. 179-187 U.S. Geological Survey, Denver Federal Center, P.O. Box 25046, MS 939, Denver, CO 80225, United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-85040236589&doi=10.1029%2fGM124p0179&partnerID=40&md5=daa3c7b9c0ff823cdec3cf318b879f4b cited By 18 M.W. Lee T.S. Collett incollection D200085 2000 978-0-444-50434-0 https://doi.org/10.1016/B978-044450434-0/50007-X Lake Baikal Elsevier Science B.V.

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Koji Minoura 85-89 https://www.sciencedirect.com/science/article/pii/B978044450434050007X D. Demske B. Mohr H. Oberhänsli incollection MATS200015 2000 978-0-444-50434-0 https://doi.org/10.1016/B978-044450434-0/50003-2 Lake Baikal Elsevier Science B.V.

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Koji Minoura 15-34 https://www.sciencedirect.com/science/article/pii/B9780444504340500032 V.D. Mats S. Fujii K. Mashiko E.Yu. Osipov I.M. Yefrimova A.V. Klimansky incollection KARABANOV200071 2000 978-0-444-50434-0 https://doi.org/10.1016/B978-044450434-0/50006-8 Lake Baikal Elsevier Science B.V.

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Koji Minoura 71-84 https://www.sciencedirect.com/science/article/pii/B9780444504340500068 E.B. Karabanov M.I. Kuzmin A.A. Prokopenko D.F. Williams G.K. Khursevich E.V. Bezrukova E.V. Kerber Gvozdkov {A. N.} Gelety {V. F.} Weil D. Schwab M. incollection KUZUMIN20001 2000 978-0-444-50434-0 https://doi.org/10.1016/B978-044450434-0/50002-0 Lake Baikal Elsevier Science B.V.

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Koji Minoura 1-14 https://www.sciencedirect.com/science/article/pii/B9780444504340500020 M.I. Kuzumin D.F. Williams T. Kawai incollection MATSUMOTO2000119 2000 978-0-444-50434-0 https://doi.org/10.1016/B978-044450434-0/50011-1 Lake Baikal Elsevier Science B.V.

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Koji Minoura 119-126 https://www.sciencedirect.com/science/article/pii/B9780444504340500111 G.I. Matsumoto S. Kosaku N. Takamatsu T. Akagi T. Kawai Y. Ambe incollection TAKAMATSU2000127 2000 978-0-444-50434-0 https://doi.org/10.1016/B978-044450434-0/50012-3 Lake Baikal Elsevier Science B.V.

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Koji Minoura 127-135 https://www.sciencedirect.com/science/article/pii/B9780444504340500123 N. Takamatsu I.G. Matsumoto N. Kato T. Kawai incollection ECKERT2000136 2000 978-0-444-50434-0 https://doi.org/10.1016/B978-044450434-0/50013-5 Lake Baikal Elsevier Science B.V.

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Koji Minoura 136-145 https://www.sciencedirect.com/science/article/pii/B9780444504340500135 C. Eckert E.V. Veinberg U. Kienel H. Oberhänsli incollection KHURSEVICH2000146 2000 978-0-444-50434-0 https://doi.org/10.1016/B978-044450434-0/50014-7 Lake Baikal Elsevier Science B.V.

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Koji Minoura 146-154 https://www.sciencedirect.com/science/article/pii/B9780444504340500147 G.K. Khursevich E.B. Karabanov D.F. Williams M.I. Kuzmin A.A. Prokopenko incollection TAKAMATSU2000155 2000 978-0-444-50434-0 https://doi.org/10.1016/B978-044450434-0/50015-9 Lake Baikal Elsevier Science B.V.

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Koji Minoura 155-164 https://www.sciencedirect.com/science/article/pii/B9780444504340500159 T. Takamatsu T. Kawai M. Nishikawa incollection KOVAL2000176 2000 978-0-444-50434-0 https://doi.org/10.1016/B978-044450434-0/50017-2 Lake Baikal Elsevier Science B.V.

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Koji Minoura 176-185 https://www.sciencedirect.com/science/article/pii/B9780444504340500172 P.V. Koval A.N. Gvozdkov V.A. Romanov incollection SEMOVSKI2000186 2000 978-0-444-50434-0 https://doi.org/10.1016/B978-044450434-0/50018-4 Lake Baikal Elsevier Science B.V.

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Koji Minoura 186-199 https://www.sciencedirect.com/science/article/pii/B9780444504340500184 S.V. Semovski incollection SEMOVSKI2000200 2000 978-0-444-50434-0 https://doi.org/10.1016/B978-044450434-0/50019-6 Lake Baikal Elsevier Science B.V.

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Koji Minoura 200-213 https://www.sciencedirect.com/science/article/pii/B9780444504340500196 S.V. Semovski incollection GRANIN2000214 2000 978-0-444-50434-0 https://doi.org/10.1016/B978-044450434-0/50020-2 Lake Baikal Elsevier Science B.V.

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Koji Minoura 214-228 https://www.sciencedirect.com/science/article/pii/B9780444504340500202 N.G. Granin R. Yu. Gnatovsky A. Kay L.M. Galkin incollection KOVAL2000165 2000 978-0-444-50434-0 https://doi.org/10.1016/B978-044450434-0/50016-0 Lake Baikal Elsevier Science B.V.

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Koji Minoura 165-175 https://www.sciencedirect.com/science/article/pii/B9780444504340500160 P.V. Koval G.V. Kalmychkov V.F. Geletyi L.D. Andrulaitis incollection TG2000229 2000 978-0-444-50434-0 https://doi.org/10.1016/B978-044450434-0/50021-4 Lake Baikal Elsevier Science B.V.

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Koji Minoura 229-235 https://www.sciencedirect.com/science/article/pii/B9780444504340500214 G. Potyomkina L. Potyomkin incollection AMANO2000315 2000 978-0-444-50434-0 https://doi.org/10.1016/B978-044450434-0/50029-9 Lake Baikal Elsevier Science B.V.

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Koji Minoura 315-323 https://www.sciencedirect.com/science/article/pii/B9780444504340500299 M. Amano Y. Koyama E.A. Petrov A. Hayano N. Miyazaki incollection K200053 2000 978-0-444-50434-0 https://doi.org/10.1016/B978-044450434-0/50005-6 Lake Baikal Elsevier Science B.V.

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Koji Minoura 53-70 https://www.sciencedirect.com/science/article/pii/B9780444504340500056 K. Kashiwaya A. Tanaka H. Sakai T. Kawai incollection SOROKOVIKOVA2000236 2000 978-0-444-50434-0 https://doi.org/10.1016/B978-044450434-0/50022-6 Lake Baikal Elsevier Science B.V.

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Koji Minoura 236-246 https://www.sciencedirect.com/science/article/pii/B9780444504340500226 L.M. Sorokovikova T.V. Khodzher V.N. Sinyukovich L.P. Golobokova N.D. Bashenkhaeva O.G. Netsvetaeva incollection SAKAI200035 2000 978-0-444-50434-0 https://doi.org/10.1016/B978-044450434-0/50004-4 Lake Baikal Elsevier Science B.V.

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Koji Minoura 35-52 https://www.sciencedirect.com/science/article/pii/B9780444504340500044 H. Sakai S. Nomura M. Horii K. Kashiwaya A. Tanaka T. Kawai V. Kravchinsky J. Peck incollection K2000324 2000 978-0-444-50434-0 https://doi.org/10.1016/B978-044450434-0/50030-5 Lake Baikal Elsevier Science B.V.

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Koji Minoura 324-330 https://www.sciencedirect.com/science/article/pii/B9780444504340500305 K. Martens I. Schön incollection YABE2000306 2000 978-0-444-50434-0 https://doi.org/10.1016/B978-044450434-0/50028-7 Lake Baikal Elsevier Science B.V.

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Koji Minoura 306-314 https://www.sciencedirect.com/science/article/pii/B9780444504340500287 M. Yabe V.G. Sideleva incollection MASHIKO2000299 2000 978-0-444-50434-0 https://doi.org/10.1016/B978-044450434-0/50027-5 Lake Baikal Elsevier Science B.V.

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Koji Minoura 299-305 https://www.sciencedirect.com/science/article/pii/B9780444504340500275 K. Mashiko R. Kamaltynov H. Morino D.Yu. Sherbakov incollection NAKATA2000281 2000 978-0-444-50434-0 https://doi.org/10.1016/B978-044450434-0/50026-3 Lake Baikal Elsevier Science B.V.

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Koji Minoura 281-298 https://www.sciencedirect.com/science/article/pii/B9780444504340500263 H. Nakata S. Tanabe H. Iwata M. Amano N. Miyazaki E.A. Petrov R. Tatsukawa incollection KIPFER2000273 2000 978-0-444-50434-0 https://doi.org/10.1016/B978-044450434-0/50025-1 Lake Baikal Elsevier Science B.V.

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Koji Minoura 273-280 https://www.sciencedirect.com/science/article/pii/B9780444504340500251 R. Kipfer F. Peeters incollection OGAWA2000262 2000 978-0-444-50434-0 https://doi.org/10.1016/B978-044450434-0/50024-X Lake Baikal Elsevier Science B.V.

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Koji Minoura 262-272 https://www.sciencedirect.com/science/article/pii/B978044450434050024X N.O. Ogawa K. Yoshii N.G. Melnik N.A. Bondarenko O.A. Timoshkin N.S. Smirnova-Zalumi V.V. Smirnov E. Wada incollection KUCKLICK2000247 2000 978-0-444-50434-0 https://doi.org/10.1016/B978-044450434-0/50023-8 Lake Baikal Elsevier Science B.V.

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Koji Minoura 247-261 https://www.sciencedirect.com/science/article/pii/B9780444504340500238 J.R. Kucklick J.E Baker article KERN1999191 The Dabie–Sulu ultrahigh-pressure (UHP) metamorphic belt of Central China represents a zone in which upper and lower continental crust has been subducted and then rapidly exhumed from the mantle back into the crust. About 30 UHP rock samples representing major lithologies were collected from surface exposures and their physical properties were measured in the laboratory at pressures up to 600 MPa (room temperature) and temperatures up to 600°C (600 MPa confining pressure). The experimentally determined data include compressional (Vp) and shear wave velocities (Vs), velocity anisotropy (shear wave splitting), density, and intrinsic pressure and temperature derivatives of Vp and Vs. Using a regional geotherm, velocity–depth profiles were calculated for the different lithologies spanning compositions from felsic through intermediate to mafic, and metamorphic grades up to granulite and eclogite facies. The velocity data, in particular the Poisson ratio (Vp/Vs ratio), were used to interpret lithologically the seismic models evaluated from seismic refraction data. The seismic velocity profiles reveal a four-layer structure (upper, middle, upper-lower and lowermost crust) with an average thickness of 34 km. From our results, we infer that a mixture of about 90% felsic gneiss with variable amounts of high Vp amphibolite/gabbro constitute the middle crust. Intermediate granulite and mafic granulite fit both the Vp and Poisson ratio of the upper-lower and lowermost crust, respectively. From the combined Vp and Poisson ratio (Vp/Vs) data, we conclude that eclogite is not a major constituent of the present Dabie deep crust. Combining the laboratory-derived in-situ seismic data (Vp and Poisson ratio) with refraction seismic data, along with evidence from geological and geochemical investigations, suggests that lower crustal delamination played an important role in the modification of the East China crust. 1999 0040-1951 https://doi.org/10.1016/S0040-1951(98)00268-6 Tectonophysics 301 191-215 3 UHP rocks, seismic properties (V and V), densities, crustal lithology, delamination https://www.sciencedirect.com/science/article/pii/S0040195198002686 Hartmut Kern Shan Gao Zhengmin Jin Till Popp Shuyan Jin article Khairkhah1999377 Immense volumes of naturally occurring gas hydrate in different parts of the world, onshore and offshore, have encouraged the belief that gas hydrate in the next century may become a viable energy resource. Various issues need to be resolved to convert gas hydrate from an energy resource to an energy reserve of real commercial value. The production capability of a gas hydrate reservoir and the gas production technique that could be utilized should be addressed through geological and petrophysical studies, well-production tests and reservoir simulation. To make the simulation of practical value, the controlling mechanisms of fluid flow, kinetics, and heat transfer should be incorporated in the model. The Mallik gas hydrate accumulation in the Mackenzie Delta has exhibited promising potential to be considered a gas reserve through the assessments made of the Mallik L-38 and 2L-38 wells. The data available from both wells and the results of production tests in JAPEX/JNOC/GSC Mallik L-38 gas hydrate research well accommodate basic requirements for comprehensive modelling of the reservoir and production of gas from the in situ gas hydrate through various methods. 1999 English 00687626 Bulletin of the Geological Survey of Canada 377-390 University of Calgary, 2500 University Drive N.W., Calgary, Alta. T2N 1N4, Canada 544 https://www.scopus.com/inward/record.uri?eid=2-s2.0-0003274682&partnerID=40&md5=f6cafb6b1282871d5d12e8ae5ee42ff5 cited By 6 D. Khairkhah article Jousset1999255 Usu volcano (Hokkaido, Japan) is a dacitic volcano, known for its high production rate of lava domes and crypto-domes. It is thus a good target to study processes of volcanic dome evolution (upheaval and/or relaxation). We carried out repeated GPS and microgravity surveys on the three most recent domes of Mt. Usu (1910: Meiji Shinzan; 1943-1945: Showa-Shinzan and 1977-1982: Usu-Shinzan). The repeat period was 1 to 2 months and extended from October 1996 to June 1997. We also compare new data with results from former studies. More than 20 years after the start of Usu-Shinzan dome growth, there is still subsidence at a maximum rate of about 7 to 8 cm/year. The reasons for this subsidence are discussed. Repeated gravity surveys revealed an increase of gravity on the domes (about 60 ± 10 microgal/year for Usu-Shinzan, about 15 microgal at Showa-Shinzan and 10 to 20 microgal for Meiji-shinzan); this gravity increase exceeds that expected due to subsidence. We discuss and interpret the excess gravity change in terms of a density increase in the edifice, caused by a combination of processes (contraction of the edifice, water level change, devesiculisation, cooling and magma intrusion). Quantification of these processes at Usu volcano may help to understand the processes of evolution at domes on other volcanoes such as Merapi (Indonesia), Unzen (Japan) or Montserrat (West Indies). Article 1999 English 03770273 10.1016/S0377-0273(99)00003-7 Journal of Volcanology and Geothermal Research 89 255 – 273 1-4 Japan; crustal deformation; gravity anomaly; lava dome; volcanic eruption https://www.scopus.com/inward/record.uri?eid=2-s2.0-0032842082&doi=10.1016%2fS0377-0273%2899%2900003-7&partnerID=40&md5=c15bf281c2d8ee51355a006c36b3ddc1 Cited by: 22 Philippe Jousset Hiromu Okada article Cranston1999165 A pore-water research program was designed to measure dissolved components in interstitial water from sediment core samples collected during the JAPEX/JNOC/GSC Mallik 2L-38 gas hydrate research-well project. Pore waters from the gas-hydrate-bearing samples had an average salinity of 8 ppt compared to 34 ppt for non-gas-hydrate-bearing samples. The difference in salinities suggests that 80-90% of the pore space in the gas-hydrate-bearing sediment was filled with gas hydrate, which dissociated during recovery. Potassium concentration was also measured in pore water, to estimate the amount of drill-mud contamination in pore-water samples, since the drill mud contained brine solution made from potassium chloride. On average, pore-water salinities were estimated to be enhanced by 2 ppt due to drill-mud contamination. 1999 English 00687626 Bulletin of the Geological Survey of Canada 165-175 Geological Survey of Canada (Atlantic), P.O. Box 1006, Dartmouth, NS B2Y 4A2, Canada 544 https://www.scopus.com/inward/record.uri?eid=2-s2.0-4644339220&partnerID=40&md5=44b2d12fc91a388b1f04b62b9cf68ffc cited By 20 R.E. Cranston article Winters199995 A 1150 m deep gas hydrate research well was drilled in the Canadian Arctic in February and March 1998 to investigate the interaction between the presence of gas hydrate and the natural conditions presented by the host sediments. Profiles of the following measured and derived properties are presented from that investigation: water content, sediment wet bulk density, grain size, porosity, gas hydrate quantity, and salinity. These data indicate that the greatest concentration of gas hydrate is located within sand and gravel deposits between 897 m and 922 m. American Society for Testing and Materials 1997: Standard test method for specific gravity of soil solids by gas pycnometer D 5550-94; in American Society for Testing and Materials, Annual Book of ASTM Standards, v. 04.09, Soil and Rock, West Conshohocken, Pennsylvania, p. 380-383. 1999 English 00687626 Bulletin of the Geological Survey of Canada 95-100 United States Geological Survey, Center for Coastal and Marine Geology, 384 Woods Hole Road, Woods Hole, MA 02543, United States 544 https://www.scopus.com/inward/record.uri?eid=2-s2.0-0008529457&partnerID=40&md5=bb8055e1b27dbc38c647619f4e21d378 cited By 34 W.J. Winters article Dallimore199911 The JAPEX/JNOC/GSC Mallik 2L-38 gas hydrate research well was drilled in February and March, 1998, in the Mackenzie Delta, Northwest Territories, Canada, to a depth of 1150 m. The scientific program was conducted through a collaborative agreement between the Japan National Oil Corporation and the Geological Survey of Canada with key participation by the Japan Petroleum Exploration Company and the United States Geological Survey. A primary objective of the well was to undertake a comprehensive scientific research program to study an arctic gas hydrate accumulation. Field research conducted as part of the Mallik 2L-38 program included collection of permafrost and gas-hydrate-bearing core samples, downhole geophysical logging, and a vertical seismic profile survey. Laboratory and modelling studies undertaken during the field program, and subsequently as part of a post-field research program, documented the sedimentology, biostratigraphy, physical/petrophysical properties, pore-water and gas geochemistry, geophysics, and reservoir characteristics of the Mallik field gas hydrate accumulation. 1999 English 00687626 Bulletin of the Geological Survey of Canada 11-17 Geological Survey of Canada, 601 Booth Street, Ottawa, Ont. K1A 0E8, Canada 544 https://www.scopus.com/inward/record.uri?eid=2-s2.0-3442901587&partnerID=40&md5=7eed157529b8c688bdbcf2e63c3360ec cited By 25 S.R. Dallimore article Katsube1999109 A petrophysical study has been performed on mudstone and sandstone samples from depths of 880-950 m to determine the petrophysical controls on gas hydrate distribution in the sedimentary sequence at the J APEX/JNOC/GSC Mallik 2L-38 well site, Northwest Territories, Canada. Within the cored interval of the Mallik 2L-38 well gas hydrate is hosted in two sandstone horizons with overlying and underlying mudstone horizons, with minor gas hydrate concentrations within some mudstone formations. Results indicate that, although the interbedded mudstone units have relatively high porosities (24-30%) and are at relatively shallow depths, they have a well developed framework-supported texture, probably due to high silt and sand content (56-78 weight per cent), and a maximum burial depth greater than present. Regardless of this, the minor matrix content (13-25 weight per cent) controls the fluid transport characteristics, resulting in extremely low mudstone permeability sections (2×10-21 m to 2×10-19 m2). There are indications that these low permeabilities and the storage pore sizes contribute to the gas hydrate distribution. 1999 English 00687626 Bulletin of the Geological Survey of Canada 109-124 Geological Survey of Canada, 601 Booth Street, Ottawa, Ont. K1A 0E8, Canada 544 https://www.scopus.com/inward/record.uri?eid=2-s2.0-8744238665&partnerID=40&md5=21203f8abc443e4c7429c7f10438bdba cited By 13 T.J. Katsube article Nakada1999173 Effusive eruption of dacite magma (2.1 X 108 m3) during 1991-1995 formed a lava dome at the summit of Unzen Volcano, Japan. The effusion rate was highest at the beginning, 4.0 X 105 m3/day (4.6 m3/s), and decreased roughly with time, to almost zero before this pattern was repeated with a second pulse of magma supply. The whole-rock chemistry of lavas shows significant variation attributable to variations in phenocryst abundance; the more mafic, the more abundant the phenocrysts. The pattern of chemical variation with time shows some difference from that of the effusion rate. All phenocrysts in dacite (plagioclase, hornblende, biotite, quartz and magnetite) show evidence of disequilibrium with melt. Although a glomerophyric aggregation of phenocrysts suggests coexistence with each other, phenocrysts are isotopically heterogeneous from species to species. The calculated initial melt composition was rhyodacite, and was nearly constant throughout the activity. In contrast, the bulk phenocryst population is andesite. A model explaining the textures and the isotopic heterogeneity is the capture of diorite fragments (or xenocrysts) by parental rhyodacite magma. It is suggested that, when effusion rate was high, less viscous crystal-poor magma exited from the reservoir. Groundmass glass and plagioclase microlite rims show temporal chemical variations correlating with the effusion rate; the higher the effusion rate, the more evolved the compositions. Groundmass crystallinity increased with decreasing effusion rate; from 33% to 50%. Textures in dome lavas suggest that groundmass crystallization had been mostly completed when magma reached the conduit top. The Fe-Ti oxide temperature (880-780°C) was low when the crystallinity was high. Micropumice erupted before dome growth provided a sample recording magmatic foam in the conduit. Porosity of dome lavas was lower at lower effusion rates. Collapse of foam magma and simultaneous escape of volatiles through the conduit top were probably responsible for the accompanying low-frequency earthquakes. Phenocrysts were broken and the breakdown rims on hornblende phenocrysts were torn off during collapse and successive compaction. When effusion waned, degassing and the resultant crystallization proceeded more completely, so that the magma became too viscous to flow in the conduit top and behaved as a plug, resulting in a temporary halt of effusion. In turn, groundmass crystallization in magma below the plug increased excess pressure in the upper parts of conduit due to slow cooling. The plug was scavenged when rising excess pressure overcame its effective strength. Then, the second pulse of magma supply began. Strong endogenous growth and extrusion of a lava spine in the later stage probably occurred for the same reason. Article 1999 English 03770273 10.1016/S0377-0273(98)00131-0 Journal of Volcanology and Geothermal Research 89 173 – 196 1-4 Japan; dacite; petrology; volcanic eruption https://www.scopus.com/inward/record.uri?eid=2-s2.0-0032818582&doi=10.1016%2fS0377-0273%2898%2900131-0&partnerID=40&md5=e81ae59e4f174edcd0f3bc72bff8c315 Cited by: 178 Setsuya Nakada Yoshinobu Motomura article Venezky1999213 A dacitic magma (64.5 wt.% SiO2), a mixture of phenocryst-rich rhyodacite and an aphyric mafic magma, was erupted during the recent 1991-1995 Mount Unzen eruptive cycle. The experimental and analytical results of this study reveal additional details about conditions in the premixing and postmixing magmas, and the nature of the mixing process. The preeruption rhyodacitic magma was at a temperature of 790 ± 20°C according to Fe-Ti oxide phenocryst cores, and at a depth of 6 to 7 km (160 MPa) according to Al-in-hornblende geobarometry. The mafic magma that mixed with the rhyodacite is found as andesitic (54 to 62 wt.% SiO2) enclaves in the erupted magma and was essentially aphyric when intruded. Phase equilibria indicate that an aphyric andesite at 160 MPa is >1030°C (H2O-saturated) and possibly as high as 1130°C (2 wt.% H2O). The composition of the rhyodacite which was mixed with the andesite is estimated to lie between 67 and 69 wt.% SiO2. Using these compositions and temperatures, the temperature of the Unzen magma after mixing is estimated to be at least 850°to 870°C. The groundmass Fe-Ti oxide microphenocrysts and those in pargasite-bearing reaction zones around biotite phenocrysts both give 890 ± 20°C temperatures; the oxide-oxide contacts give temperatures of 910 ± 20°C. The 900 ± 30°C postmixing temperatures are consistent with phase-equilibria experiments which show that the magma was not above 930°C at 160 MPa. Our Fe-Ti oxide reequilibration experiments suggest that the mixing of the two magmas began within a few weeks of the eruption, which is a shorter time than is calculated using available diffusion data. There is also evidence that some mixing took place much closer to the time of extrusion based on the presence of unrimmed biotite phenocrysts in the magma. Article 1999 English 03770273 10.1016/S0377-0273(98)00133-4 Journal of Volcanology and Geothermal Research 89 213 – 230 1-4 Japan; dacite; geobarometry; magma chemistry; petrology; volcanic eruption https://www.scopus.com/inward/record.uri?eid=2-s2.0-0032856599&doi=10.1016%2fS0377-0273%2898%2900133-4&partnerID=40&md5=09f16d72165e8c1aba8c5c851cd1cff8 Cited by: 171 Dina Y. Venezky Malcolm J. Rutherford article White199981 The JAPEX/JNOC/GSC Mallik 2L-38 gas hydrate research well was drilled in 1998 to investigate the geological, geochemical, geophysical, and engineering properties of a gas hydrate accumulation previously identified in the Mallik L-38 well. Palynological analysis of core and cuttings from 670 m to 1150 m (TD) are reported here. Detailed quantitative analysis has been done on the 886-952 m cored interval that hosts the main gas hydrate accumulation. The pollen and spore evidence suggests the following biostratigraphic subdivisions for the 670-1150 m succession: 670-785 m, Late Miocene or older; 775-897 m, within the range of Early Miocene to Late Eocene; 897-930 m, probably Late Eocene; 930-995 m, Late Eocene; and 995-1151m within the range Early to Middle Eocene. Below 930 m the rocks are best assigned to the Richards and upper Taglu sequences. A dominantly continental succession is indicated, with a marginal marine and/or estuarine episode between about 945 m and 948 m, in the Late Eocene. The dinoflagellates in this interval are considered to be indigenous to the sampled rock. There is evidence of two episodes of edaphic-climatic dryness in the Late Eocene and probable Late Eocene. 1999 English 00687626 Bulletin of the Geological Survey of Canada 81-93 Geological Survey of Canada (Calgary), 3303-33rd Street N.W., Calgary, Alta. T2L 2A7, Canada 544 Dinophyceae https://www.scopus.com/inward/record.uri?eid=2-s2.0-27844456805&partnerID=40&md5=ea401d462158017e5c255465864fc498 cited By 3 J.M. White article Nakada19991 Following 198 years of dormancy, a small phreatic eruption started at the summit of Unzen Volcano (Mt. Fugen) in November 1990. A swarm of volcano-tectonic (VT) earthquakes had begun below the western flank of the volcano a year before this eruption, and isolated tremor occurred below the summit shortly before it. The focus of VT events had migrated eastward to the summit and became shallower. Following a period of phreatic activity, phreatomagmatic eruptions began in February 1991, became larger with time, and developed into a dacite dome eruption in May 1991 that lasted approximately 4 years. The emergence of the dome followed inflation, demagnetization and a swarm of high-frequency (HF) earthquakes in the crater area. After the dome appeared, activity of the VT earthquakes and the summit HF events was replaced largely by low-frequency (LF) earthquakes. Magma was discharged nearly continuously through the period of dome growth, and the rate decreased roughly with time. The lava dome grew in an unstable form on the shoulder of Mt. Fugen, with repeating partial collapses. The growth was exogenous when the lava effusion rate was high, and endogenous when low. A total of 13 lobes grew as a result of exogenous growth. Vigorous swarms of LF earthquakes occurred just prior to each lobe extrusion. Endogenous growth was accompanied by strong deformation of the crater floor and HF and LF earthquakes. By repeated exogenous and endogenous growth, a large dome was formed over the crater. Pyroclastic flows frequently descended to the northeast, east, and southeast, and their deposits extensively covered the eastern slope and flank of Mt. Fugen. Major pyroclastic flows took place when the lava effusion rate was high. Small vulcanian explosions were limited in the initial stage of dome growth. One of them occurred following collapse of the dome. The total volume of magma erupted was 2.1 x 108 m3 (dense-rock-equivalent); about a half of this volume remained as a lava dome at the summit (1.2 km long, 0.8 km wide and 230-540 m high). The eruption finished with extrusion of a spin endogenous dome top. Several monitoring results convinced us that the eruption had come to an end: the minimal levels of both seismicity and rockfalls, no discharge of magma, the minimal SO2 flux, and cessation of subsidence of the western flank of the volcano. The dome started slow deformation and cooling after the halt of magma effusion in February 1995. Article 1999 English 03770273 10.1016/S0377-0273(98)00118-8 Journal of Volcanology and Geothermal Research 89 1 – 22 1-4 Japan; earthquake; lava dome; pyroclastic flow; volcanic eruption https://www.scopus.com/inward/record.uri?eid=2-s2.0-0032840270&doi=10.1016%2fS0377-0273%2898%2900118-8&partnerID=40&md5=f1d1e57c93d8235872c64299815a2925 Cited by: 274 Setsuya Nakada Hiroshi Shimizu Kazuya Ohta article Dallimore199931 The occurrence of natural gas hydrate within Cenozoic sediments of the Mackenzie Delta-Beaufort Sea region has been well documented. In preparation for the JAPEX/JNOC/GSC Mallik 2L-38 gas hydrate research well, a detailed evaluation of terrestrial gas hydrate occurrences was undertaken to assess the geological setting, sediment associations, pressure and temperature conditions, and the presence of free gas in the Mackenzie Delta-Beaufort Sea region. After an exhaustive review, it was determined that the Mallik L-38 site, drilled by Imperial Oil in 1972, offered the highest probability of encountering a thick gas hydrate occurrence with high gas hydrate concentrations. On the basis of openhole well-log evaluation, it was estimated that about Him of gas-hydrate-bearing strata occur at this location from 810.1 to 1102.3 m, within the zone of predicted methane hydrate stability and below the base of icebearing permafrost, estimated to be at 640 m. 1999 English 00687626 Bulletin of the Geological Survey of Canada 31-43 Geological Survey of Canada, 601 Booth Street, Ottawa, Ont. K1A 0E8, Canada 544 https://www.scopus.com/inward/record.uri?eid=2-s2.0-27844491511&partnerID=40&md5=4b68ff0fc6d57e636fd5ea0e73a5f1ee cited By 47 S.R. Dallimore article Winters1999241 As part of an ongoing laboratory study, preliminary acoustic, strength, and hydraulic conductivity results are presented from a suite of tests conducted on four natural-gas-hydrate-containing samples from the Mackenzie Delta JAPEX/JNOC/GSC Mallik 2L-38 gas hydrate research well. The gas hydrate samples were preserved in pressure vessels during transport from the Northwest Territories to Woods Hole, Massachusetts, where multistep tests were performed using GHASTLI (Gas Hydrate And Sediment Test Laboratory Instrument), which recreates pressure and temperature conditions that are stable for gas hydrate. Properties and changes in sediment behaviour were measured before, during, and after controlled gas hydrate dissociation. Significant amounts of gas hydrate occupied the sample pores and substantially increased acoustic velocity and shear strength. 1999 English 00687626 Bulletin of the Geological Survey of Canada 241-250 United States Geological Survey, Center for Coastal and Marine Geology, 384 Woods Hole Road, Woods Hole, MA 02543, United States 544 https://www.scopus.com/inward/record.uri?eid=2-s2.0-0013261763&partnerID=40&md5=8710460ee327df6188790aa06b040820 cited By 34 W.J. Winters article Kusakabe1999231 Water contents and hydrogen isotopic ratios were determined for blocks from pyroclastic flow deposits, and bread-crust bombs and blocks from the 1991 Vulcanian eruptions of Unzen volcano, Japan. Groundmass water contents and δD values of samples were calculated by subtracting the contribution of major hydrous minerals (hornblende and biotite) from the bulk rock analyses, and range from 0.1 to 0.5 wt.% and -83 to -49‰, respectively. The samples do not show a systematic H2O-δD relationship, although the block samples tend to have lower δD values than the bomb samples. The non-systematic H2O-δD relationship is likely a result of near surface, kinetically-controlled gas loss. High viscosity of this magma would hinder attainment of hydrogen isotopic equilibrium between exsolved vapor and melt in the final degassing stage. The near surface degassing, however, was accompanied by kinetic fractionation resulting in enrichment of deuterium in the final products as exemplified by bread-crust bombs with high H2O-low δD margins and low H2O-high δD cores. Relatively high δD values of the blocks and bombs as well as high temperature volcanic gas (-30 to -35‰) suggest a closed system degassing of an initial water-rich magma (H2O = 6 wt.%) until its water content was reduced to 0.5 wt.%. The pre-eruptive δD value (-46‰) was estimated from the volcanic gas data and D/H analysis of hornblende phenocrysts coupled with assumed isotopic equilibration in the initial hydrous magma. Article 1999 English 03770273 10.1016/S0377-0273(98)00134-6 Journal of Volcanology and Geothermal Research 89 231 – 242 1-4 Japan; degassing; hydrogen isotope; igneous geochemistry; volcanic eruption; water content https://www.scopus.com/inward/record.uri?eid=2-s2.0-0032842081&doi=10.1016%2fS0377-0273%2898%2900134-6&partnerID=40&md5=f23056aa528d17e3e2f1f083eb093004 Cited by: 32 Minoru Kusakabe Hiroaki Sato Setsuya Nakada Toshihiro Kitamura book NoAuthor19991 Natural gas hydrate, a solid form of natural gas and water, is thought to be the single most abundant hydrocarbon source known on Earth. This unique substance occurs in nature in association with deep permafrost and in offshore environments adjacent to continental margins. The scientific results of the JAPEX/JNOC/GSC Mallik 2L-38 gas hydrate research well, which are the successful outcome of a collaborative agreement between the Geological Survey of Canada (GSC) and the Japan National Oil Corporation (JNOC), are presented in this report. For the GSC, the collaboration provided the first detailed characterization of the vast gas hydrate occurrences known to occur beneath the Mackenzie Delta, one of Canada's largest undeveloped hydrocarbon provinces. Although gas hydrate research during the past three decades has been primarily related to geohazard concerns, in recent years the GSC has begun to examine the potential of gas hydrate as an energy resource and the role it may play as a source of greenhouse gases that contribute to climate change. 1999 English 0660177773 Scientific results from JAPEX/JNOC/GSC Mallik 2L-38 gas hydrate research well, Mackenzie Delta, Northwest Territories, Canada. Geological survey of Canada bulletin No.544. Geological Survey of Canada Dallimore S.R., Uchida T., Collett T.S. 1-401 continental margin; energy resource; gas hydrate; greenhouse gas; hydrocarbon exploration; permafrost, Canada https://www.scopus.com/inward/record.uri?eid=2-s2.0-0033496470&partnerID=40&md5=c1172d367bbc8dc67cd24996dcba524d cited By 0 article Jenner199957 A detailed sedimentological program has been conducted on gas-hydrate-bearing core samples from the JAPEX/JNOC/GSC Mallik 2L-38 gas hydrate research well. Three structurally and texturally distinct sedimentary facies are identified. Facies Csc (952.2-926.5 m) is a weakly bioturbated, clayey silt interbedded with fissile coal and silty sand. Facies Sg (926.5-908.5 m) is comprised of interbedded, finingupward successions of matrix-supported gravel to pebbly sand and fine sand. A dolomite-cemented sandstone (926.5-925 m) forms a distinct basal subfacies (Sst). Facies Ss (908.5-886.2 m) is a fine- to mediumgrained sand interbedded with gravel which fines upward to fine-grained sand with a gradational increase in silt content. The Kugmallit-Mackenzie Bay sequence boundary is interpreted to occur at the base of facies Sg. In situ and self-preserved gas hydrate occurred mainly in the sands and gravels of the Sg and Ss facies. The dolomite-cemented sandstone (subfacies Sst) may be related to complementary geochemical environments resulting from the formation of authigenic pyrite and solute exclusion related to gas hydrate growth within facies Sg. 1999 English 00687626 Bulletin of the Geological Survey of Canada 57-68 Geological Survey of Canada (Atlantic), P.O. Box 1006, Dartmouth, NS B2Y 4A2, Canada 544 https://www.scopus.com/inward/record.uri?eid=2-s2.0-27844552879&partnerID=40&md5=dd75d13cb21dfa2cf7eabed58445e00b cited By 14 K.A. Jenner article Collett1999357 The gas hydrate stability zone is areally extensive beneath most of the Mackenzie Delta-Beaufort Sea region, with the base of the gas hydrate stability zone more than 1000 m deep on Richards Island. In this study, gas hydrate has been inferred to occur in nine Richards Island exploratory wells on the basis of well-log responses calibrated to the response of the logs within the cored gas-hydrate-bearing intervals of the JAPEX/JNOC/GSC Mallik 2L-38 gas hydrate research well. The integration of the available well-log data with more than 240 km of industry-acquired reflection seismic data have allowed us to map the occurrence of four significant gas hydrate and associated free-gas accumulations in the Ivik-Mallik-Taglu area on Richards Island. The occurrence of gas hydrate on Richards Island is mostly restricted to the crest of large anticlinal features that cut across the base of the gas hydrate stability zone. Combined seismic and well-log data analysis indicate that the known and inferred gas hydrate accumulations on Richards Island may contain as much as 187 178106 m3 of gas. 1999 English 00687626 Bulletin of the Geological Survey of Canada 357-376 United States Geological Survey, Denver Federal Center, MS-939, Denver, CO 80225, United States 544 https://www.scopus.com/inward/record.uri?eid=2-s2.0-27844537822&partnerID=40&md5=73eae20cb50ac4546342de11dc9eef9a cited By 26 T.S. Collett article Uchida1999205 The JAPEX/JNOC/GSC Mallik 2L-38 gas hydrate research well was drilled to a depth of 1150 m in the Mackenzie Delta, Northwest Territories, Canada, in February and March, 1998. A highlight of the project was the successful retrieval of natural gas hydrate samples in a variety of sediments. A summary is presented of research conducted by the Japanese research consortium led by the Japan National Oil Corporation with participation by ten Japanese companies and institutes. Fingerprints of the gas hydrate crystal structure and the molar ratio of water to guest-gas molecules occupying lattice sites are described for gas-hydrate-bearing samples as obtained by NMR and Raman spectroscopy. X-Ray CT imagery is used to describe the texture and gas hydrate/sediment characteristics of recovered samples during controlled dissociation testing. In addition, inorganic and organic chemical, thermal geophysical, and physical properties are described for key core horizons. Results are also presented documenting the rate of gas hydrate dissociation in drilling fluids with different chemistry including lecithin. 1999 English 00687626 Bulletin of the Geological Survey of Canada 205-228 JAPEX Research Center, Japan Petroleum Exploration Company, Ltd., 1-2-1 Hamada, Mihama-ku, Chiba 261-0025, Japan 544 https://www.scopus.com/inward/record.uri?eid=2-s2.0-27844564294&partnerID=40&md5=35c2a611c6e39ae7ac892cdb4d13b553 cited By 15 T. Uchida article Fujii1999159 Large-scale collapse of a dacite dome in the late afternoon of 15 September 1991 generated a series of pyroclastic-flow events at Unzen Volcano. Pyroclastic flows with a volume of 1 X 106 m3 (as DRE) descended the northeastern slope of the volcano, changing their courses to the southeast due to topographic control. After they exited a narrow gorge, an ash-cloud surge rushed straight ahead, detaching the main body of the flow that turned and followed the topographic lows to the east. The surge swept the Kita-Kamikoba area, which had been devastated by the previous pyroclastic-flow events, and transported a car as far as 120 m. Following detachment, the surge lost its force after it moved several hundred meters, but maintained a high temperature. The deposits consist of a bottom layer of better-sorted ash (unit 1), a thick layer of block and ash (unit 2), and a thin top layer of fall-out ash (unit 3). Unit 2 overlies unit 1 with an erosional contact. The upper part of unit 2 grades into better-sorted ash. At distal block-and-ash flow deposits, the bottom part of unit 2 also consists of better-sorted ash, and the contact with the unit 1 deposits becomes ambiguous. Video footage of cascading pyroclastic flows during the 1991-1995 eruption, traveling over surfaces without any topographic barriers, revealed that lobes of ash cloud protruded intermittently from the moving head and sides, and that these lobes surged ahead on the ground surface. This fact, together with the inspection by helicopter shortly after the events, suggests that the protruded lobes consisted of better-sorted ash, and resulted in the deposits of unit 1. The highest ash-cloud plume at the Oshigadani valley exit, and the thickest deposition of fall-out ash over Kita-Kamikoba and Ohnokoba, indicate that abundant ash was also produced when the flow passed through a narrow gorge. In the model presented here, the ash clouds from the pyroclastic flows were composed of a basal turbulent current of high concentration (main body), an overriding and intermediate fluidization zone, and an overlying dilute cloud. Release of pressurized gas in lava block pores, due to collisions among blocks and the resulting upward current, caused a zone of fluidization just above the main body. The mixture of gas and ash sorted in the fluidization zone moved ahead and to the side of the main body as a gravitational current, where the ash was deposited as surge deposits. The main body, which had high internal friction and shear near its base, then overran the surge deposits, partially eroding them. When the upward current of gas (fluidization) waned, better-sorted ash suspended in the fluidization zone was deposited on block-and-ash deposits. In the distal places of block-and-ash deposits, unit 2 probably was deposited in non-turbulent fashion without any erosion of the underlying layer (unit 1). Article 1999 English 03770273 10.1016/S0377-0273(98)00130-9 Journal of Volcanology and Geothermal Research 89 159 – 172 1-4 Japan; ash flow; pyroclastic flow; volcanic ash; volcanic eruption https://www.scopus.com/inward/record.uri?eid=2-s2.0-0032840272&doi=10.1016%2fS0377-0273%2898%2900130-9&partnerID=40&md5=de8bba4cdb31ef25adbb1bb33d1f6dd3 Cited by: 75 Toshitsugu Fujii Setsuya Nakada article Karabanov19991269 In 1996, boreholes BDP-96-1 and BDP-96 penetrated the bottom sediments of Lake Baikal. From the lithological and geochemical correlation of the sediments, the loss from the upper layer of sediments in the cores is estimated: 630 cm (BDP-96-1) and 19 cm (BDP-96-2). Correlation of these cores with the 120 cm long core from borehole GC-1, taken with a gravity corer during the drilling through the lake ice, permits compilation of a general continuous record of climatic changes in Central Asia for the last 5 Ma and prevention of loss of Holocene sediments. Article 1999 Russian 00167886 Geologiya i Geofizika 40 1269 – 1271 8 https://www.scopus.com/inward/record.uri?eid=2-s2.0-24944540433&partnerID=40&md5=049c9b51fff3223a10552b9c7ce8f876 Cited by: 0 E.B. Karabanov M.I. Kuz'min V.F. Geletii G.V. Kalraychkov A.N. Gvozdkov article Chen1999243 The magma generation at Unzen volcano may be considered as the product of crustal material mixed with mantle magma accompanied by fractional crystallization (AFC). The magma in the Unzen volcano is estimated to consist of about 50-80% of residual magma (F) and about 30-70% assimilated crustal material (A) relative to the original magma. Concerning the 1991-1995 eruption, it is estimated that the magma formed as the result of mixing of about 50-60% crustal material and about 55-65% of residual magma. An alternative magma eruption model for the 1991-1995 eruption is proposed here. In the early stage, the isotopic characteristics of 1991 eruption are defined by AFC process in the deeper magma chamber. Later, the magma ascended through the conduit and quiescently stayed for a long time in a shallow reservoir before eruption. The minerals continuously crystallized as phenocrysts especially at the chilled top and outer margin in the shallow chamber. The crystallized phenocryst mush was reworked into the central part of the magma chamber by means of magma convection and rapid magma ascent. Therefore, the reaction between phenocrysts and melt occurs only in internal chemical disequilibrium in the magma chamber. In contrast, the isotopic compositions of the original magma shall be little influenced by the above processes throughout its eruptive history. The 1991-1995 eruptive rocks of the Unzen volcano show their characteristics in Sr and Nd isotopic values independent of their two previous eruptions. However, the isotopic values of early eruptive product could represent the original magma value. This result also supports the previous work of Chen et al. (1993) [Chen, C.H., DePaolo, D.J., Nakada, S., Shieh, Y.N., 1993. Relationship between eruption volume and neodymium isotopic composition at Unzen volcano. Nature 362, 831-834], that suggested the εNd of early or precursory eruptive products could be a qualitative indicator of the maximum size of a continuing or impending eruption. Article 1999 English 03770273 10.1016/S0377-0273(99)00002-5 Journal of Volcanology and Geothermal Research 89 243 – 253 1-4 Japan; isotopic analysis; magma chemistry; phenocryst; volcanic eruption https://www.scopus.com/inward/record.uri?eid=2-s2.0-0032819439&doi=10.1016%2fS0377-0273%2899%2900002-5&partnerID=40&md5=94ddac5b1070c812d614c2ae71119b38 Cited by: 20 Chang-Hwa Chen Setsuya Nakada Yuch-Ning Shieh Donald J. DePaolo article Webb1999621 The Hong'an block is the best place to study the exhumation of high-pressure (HP) and ultrahigh-pressure (UHP) metamorphic rocks in the Qinling-Dabie orogen of eastern China because it lacks the extensive Cretaceous tectonic and thermal overprint observed in the Dabie Shan. We measured timing of deformation and rate of cooling of the HP-UHP rocks by 40Ar/39Ar analyses of synkinematic minerals from tectonites of key structural zones in the Hong'an and Tongbai Shan. Normal-sense shear along the north dipping Huwan detachment at the northern edge of the Hong'an block occurred between 237 and 231 Ma; this detachment facilitated the bulk of the exhumation of the HP-UHP rocks. Our new 40Ar/39Ar ages, combined with U/Pb zircon and Sm/Nd ages of 245-240 Ma, suggest that exhumation of UHP rocks from mantle depths occurred at rates of 5-25 mm/yr from ~245 to 230 Ma. The mountain range is a warped extensional footwall, within which white mica cooled from 225 to 205 Ma. Locally, younger extension is recorded by white mica recrystallization at 198-194 Ma, after which the entire block had cooled to below 300 °C. Early Cretaceous 40Ar/39Ar ages from the Tongbai shear zone indicate that dextral shear along the southwest boundary of the orogen was contemporaneous with normal to sinistral-oblique slip along the Xiaotian-Mozitan fault along the northern boundary. Coeval dextral and sinistral shear zones along the northern and southwestern margins of the Hong'an and Dabie Shan would have caused eastward lateral extrusion of these two blocks, perhaps driven by collision of the Lhasa block with Eurasia. Article 1999 English 02787407 10.1029/1999TC900012 Tectonics 18 Blackwell Publishing Ltd 621 – 638 4 China; Qinling-Dabie Orogen; Deformation; Geochronology; Mica; Rocks; Silicate minerals; Early Cretaceous; Lateral extrusion; Mountain ranges; Qinling-Dabie orogen; Rate of cooling; Sinistral shear; Ultra-high-pressure metamorphic rocks; Ultrahigh pressure rocks; cooling; deformation; petrology; ultrahigh pressure metamorphism; Metamorphic rocks https://www.scopus.com/inward/record.uri?eid=2-s2.0-0033434105&doi=10.1029%2f1999TC900012&partnerID=40&md5=1ddb3c21da23131fddcc7d5b92c5d96e Cited by: 202; All Open Access, Green Open Access Laura E. Webb Bradley R. Hacker Lothar Ratschbacher Michael O. McWilliams Shuwen Dong article Sakai1999323 A VSP survey was conducted at the JAPEX/JNOC/GSC Mallik 2L-38 gas hydrate research well to determine elastic-wave velocities that were estimated by traveltime inversion of zero-offset VSP and wavefield inversion of offset VSP data. Shear-wave velocity is estimated to be slower from VSP data than from wireline DSI measurements in the depth interval from 677 m to 889 m. The compressional-wave velocity difference between the VSP- and DSI-derived velocities are comparatively small. Synthetic seismograms from the drift-corrected DSI velocity log correlate well with VSP sections, especially for compressional waves. Azimuthal anisotropy is suggested in VSP shear-source data and the mode of anisotropy appears to change around the base of permafrost. By comparing computed elastic velocities with drift-corrected DSI velocity logs, two opposing gas hydrate saturation models are examined. Shear wave velocity proved to be the key data to select the correct model. The observed elastic velocity fits the computed elastic velocity for the model of gas hydrate disseminated in pore-space with little cementation at the grain boundaries. 1999 English 00687626 Bulletin of the Geological Survey of Canada 323-340 Japan Petroleum Exploration Company, Ltd. (JAPEX), 2-2-20 Higashi-shinagawa, Shinagawa-ku, Tokyo 140-0002, Japan 544 https://www.scopus.com/inward/record.uri?eid=2-s2.0-0001817391&partnerID=40&md5=c6df09a151fc041c9a94540a522fa0c8 cited By 42 A. Sakai article Walia1999341 As part of the JAPEX/JNOC/GSC Mallik 2L-38 field program, a vertical seismic profiling(VSP) survey was carried out at zero and offset-source positions with multicomponent receiver tools and multipolarized vibrators. The results will be integrated with downhole logs and regional seismic data to evaluate the effect of gas hydrate on seismic velocity and to estimate gas hydrate concentrations. The excellent data quality allows accurate compressional-and shear-velocity depth profiles. There are down-going and up-going waves from numerous reflectors, and corridor stacks provide comparison with surface multi-channel data. Velocities in the permafrost zone above 600 m are enhanced, to more than 2500 m/s. In the largely unfrozen section from 600 m to 850 m, the velocities are lower, about 2000 m/s. The gas hydrate zone is well defined below about 900 m, with velocities of 2500-2700 m/s. Poisson's Ratio is ∼0.39 in both the permafrost and gas hydrate sections, compared to -0.44 in the unfrozen sections. 1999 English 00687626 Bulletin of the Geological Survey of Canada 341-355 CGG Geophysics Canada, 404 6th Avenue S.W., Calgary, Alta. T2P 0R9, Canada 544 https://www.scopus.com/inward/record.uri?eid=2-s2.0-2942571807&partnerID=40&md5=7e9d9f67300e8758819ea6d6018c4ef5 cited By 6 R. Walia conference Mi1999 Natural gas hydrate is receiving recent attention and exploration interest because it may represent a large clean energy resource. Gas hydrate is an ice-like nonstoichiometric inclusion compound with water molecules forming a three-dimensional network in which small molecules (guests) can be trapped. For most occurrences, the gas is biogenic methane. A large volume of methane in natural gas hydrate may exist beneath some deep sea continental slopes and arctic land areas. This paper presents preliminary VSP results from a gas hydrate research well drilled in the Canadian Arctic. © 1999 Society of Exploration Geophysicists. All rights reserved. 1999 English 1999 SEG Annual Meeting Society of Exploration Geophysicists CREWES Project, University of Calgary, Canada; SEOS, University of Victoria, CGG Geophysics Canada, Canada; Pacific Geoscience Centre, Canada; Japan Petroleum Exploration Ltd., Japan Energy resources; Gases; Hydration; Methane; Molecules; Natural gas; Natural gas deposits; Petroleum prospecting; Seismic prospecting; Seismology; Well drilling, Canadian Arctic; Continental slope; Inclusion compounds; Non-stoichiometric; Small molecules; Three-dimensional networks; Vertical seismic profiles; Water molecule, Gas hydrates https://www.scopus.com/inward/record.uri?eid=2-s2.0-85058411795&partnerID=40&md5=76b405bc78d7c8acc89d64f2bd8e1983 cited By 0 Y. Mi R. Walia R.D. Hyndman A. Sakai article Yamashina199973 Using a pair of old and new photographs taken at the same location, a method named as a time-differential stereoscopy is successfully applied to detect visually the deformation at Unzen volcano, Japan. On September 6, 1992, gradual movement of a lava lobe was visible in a stereo image as relief surrounded by immobile areas. In this case, accelerated movement of a lava block was detected immediately before the time of its collapse, which resulted in the occurrence of a pyroclastic flow. In November 1994, growth of a lava spine was also measured with time-differential stereoscopy. A possible fluctuation of the growth rate might have correlated with an abnormal oscillation of tilt, with a period of about 40 h. This convenient photographic method is recommended for various occasions to detect volcanic and any other deformations as a supplement to precise instrumental measurements. Article 1999 English 03770273 10.1016/S0377-0273(98)00124-3 Journal of Volcanology and Geothermal Research 89 73 – 80 1-4 Japan; crustal deformation; lava flow; stereo image; volcanic eruption https://www.scopus.com/inward/record.uri?eid=2-s2.0-0032876063&doi=10.1016%2fS0377-0273%2898%2900124-3&partnerID=40&md5=bfd71a350c11e740723e77dd2671ceaa Cited by: 22 Ken'Ichiro Yamashina Takeshi Matsushima Shiro Ohmi article Miyairi1999281 Techniques for evaluating subsurface natural gas hydrate were part of the JNOC/GSC/J APEX joint research project. The physical properties of pure methane hydrate, related to well-log responses, were directly measured and/or calculated based on its physico-chemical properties. A petrophysical model of the pore-filling gas hydrate was built considering the existence of thermally dissociated free gas in the pores of the formation. Tool sensitivity to gas hydrate content was analyzed, and formation resistivity and acoustic transit time were found to show distinct sensitivity. Three practical methods for evaluating gas hydrate content were proposed and were tested to confirm their applicability: 1) the resistivity method, 2) the acoustic-velocity method, and 3) the statistical-inversion-analysis method. The porosity and gas hydrate saturation results calculated from these methods agreed quite well. Thus, reasonable interpretations can be achieved using these methods if the drilling and log measurements are carefully designed, and the zoning and parameter settings are made properly in pore-filling-type gas hydrate occurrences similar to those found in the JAPEX/JNOC/GSC Mallik 2L-38 gas hydrate research well. 1999 English 00687626 Bulletin of the Geological Survey of Canada 281-293 JAPEX Research Center, Japan Petroleum Exploration Company, Ltd., 1-2-1 Hamada, Mihama-ku, Chiba 261-0025, Japan 544 https://www.scopus.com/inward/record.uri?eid=2-s2.0-0013263687&partnerID=40&md5=ea874a8ff907e58704f90e58562b24f3 cited By 14 M. Miyairi article Uchida1999197 The JAPEX/JNOC/GSC Mallik 2L-38 gas hydrate research well was drilled through a thick interbedded sequence of gas-hydrate-bearing sediments between 896 and 1106 m. In total, 37.3 m of core were collected between 886 and 952.6 m, using a variety of coring systems. Visual observations at the drill site identified a predominance of pore-space gas hydrate in varying concentrations within framework-supported sands and pebbly sands. Gas hydrate was mainly fine grained (<2 mm), filling the intergranular pores and/or coating mineral grains. Although rare, thin veins (1-2 mm) and clasts or nodules of gas hydrate (up to 0.5 mm) were also observed. The largest gas hydrate occurrence (2 cm in diameter) formed the matrix of a granular sand at 913 m. X-ray CT imagery, carried out in Japan, has identified eight well constrained signatures of the constituent components of the gas-hydrate-bearing sands and granular sands. These images have been used to establish textural characteristics and the relationship between sediment grains and gas hydrate. 1999 English 00687626 Bulletin of the Geological Survey of Canada 197-204 JAPEX Research Center, Japan Petroleum Exploration Company, Ltd., 1 -2-1 Hamada, Mihama-ku, Chiba 261-0025, Japan 544 https://www.scopus.com/inward/record.uri?eid=2-s2.0-2142665479&partnerID=40&md5=c4a0e78b48ab3eb225f233092c5f02c7 cited By 9 T. Uchida article McNeil199969 Core and cuttings samples from the JAPEX/JNOC/GSC Mallik 2L-38 gas hydrate research well in the Mackenzie Delta have yielded sparse terrestrial microfossils and abundant reworked Cretaceous foraminifers (silicified) and plant microfossils. No definitely in situ marine microfossils were recovered in the borehole (total depth 1150m; gas hydrate at 896-1110m). Cores from 110-118 m and 173-175 m contained terrestrial microfossils including fungi, seeds, insect fragments, and abundant macerated plant fragments typical of the Pliocene-Pleistocene Iperk Sequence in the Mackenzie-Beaufort Basin. Core from 886-951 m and cuttings samples from 670-870 and 960-1140 m yielded reworked algal cysts, seed casings, and megaspores. In addition, cuttings contained reworked Cretaceous agglutinated foraminifers. Core and cuttings samples were also characterized by quartz, chert, brownish-black lignite, coaly fragments, and rare amber. The lithology of the section below 670 m is characteristic of the Oligocene Kugmallit Sequence in the Mackenzie-Beaufort Basin. 1999 English 00687626 Bulletin of the Geological Survey of Canada 69-75 Geological Survey of Canada (Calgary), 3303-33rd Street N.W., Calgary, Alta. T2L 2A7, Canada 544 algae; Foraminifera; Fungi; Hexapoda https://www.scopus.com/inward/record.uri?eid=2-s2.0-27844533982&partnerID=40&md5=cf4eb63b19f08e56c32a96acd5776239 cited By 2 D.H. McNeil article Miller1999275 Holocene eruptions from Mount Dutton, a small Late Quaternary volcano near the tip of the Alaska Peninsula, bear strong physical and petrologic similarities to the 1990-1995 Unzen Fugendake eruption in Japan. The volcano had a protracted phase of effusive calcalkaline andesitic (54-59 wt.% SiO2) cone-building in the late Pleistocene followed by an abrupt switch to more silicic (~ 65 wt.% SiO2) lavas, emplaced as a central summit cluster of steep-sided domes beginning in the early Holocene. The flanks of the volcano are mantled by pyroclastic flows, debris flows, and talus formed as a result of gravitational dome collapse. Disequilibrium mineral assemblages, including coexisting quartz and olivine in eruptive episodes ranging from the initial cone-building basaltic andesite lavas to the latest Holocene dacite domes, suggest extensive magma mixing. In addition, up to meter-sized, pillow-like cognate mafic enclaves of hornblende + plagioclase + glass are common in the latest of the summit dacite domes. Mineralogical evidence and bulk chemical data indicate the enclaves represent a high-alumina basalt parent with variable and subordinate reservoir contaminant, and the host lava is reservoir magma with variable and subordinate basaltic contaminant. Mount Dutton's history and petrology can be interpreted as reflecting the monotonous repetitive intrusion of mantle-derived mafic magma into a silicic crystal-rich crustal reservoir. During the Holocene, these injections resulted in the extrusion of partially crystallized, viscous, 'sticky' central domes which typically failed by collapse resulting in small volume Merapi-type flowage deposits. We speculate that slow introduction of mafic magma into the silicic chamber leads both to enclave formation and to the effusive eruption style. Mount Dutton volcano experienced severe shallow earthquake swarms in 1984, 1988, and to a lesser extent in 1991; although none of these swarms resulted in an eruption, their epicenter distribution and volcanic-tectonic character indicate they recorded the movement of magma at shallow depth beneath the volcano. The lessons of Unzen and Montserrat suggest that, despite limited tephra production, these small volcanic centers with central dome complexes present a serious hazard to life and property. Article 1999 English 03770273 10.1016/S0377-0273(99)00004-9 Journal of Volcanology and Geothermal Research 89 275 – 301 1-4 Japan; United States; Holocene; lava dome; magma chemistry; volcanic eruption https://www.scopus.com/inward/record.uri?eid=2-s2.0-0032867234&doi=10.1016%2fS0377-0273%2899%2900004-9&partnerID=40&md5=3651f2866a2b829449ec6df9e86dd861 Cited by: 36 T.P. Miller D.G. Chertkoff J.C. Eichelberger M.L. Coombs article Ui1999123 Processes generating block and ash flows by gravitational dome collapse (Merapi-type pyroclastic flow) were observed in detail during the 1990-1995 eruption of Unzen volcano, Japan. Two different types were identified by analysis of video records and observations during helicopter flights. Most of the block and ash flows erupted during the 1991-1993 exogenous dome growth stage initially involved crack propagation due to cooling and flowage of the dome lava lobes. The mass around the crack became unstable, locally decreasing in tensile strength. Finally, a slab separated from the lobe front, fragmented progressively from the base to the top within a few seconds, and became a block and ash flow. Rock falls immediately followed, in response to local instability of the lobe front. Clasts in these rock falls fragmented and merged with the preceding flow. In contrast, block and ash flows during the endogenous dome growth stage in 1994 were generated due to local bulge of the dome. Unstable lava blocks collapsed and subsequently fragmented to produce block and ash flows. Article 1999 English 03770273 10.1016/S0377-0273(98)00128-0 Journal of Volcanology and Geothermal Research 89 123 – 137 1-4 Japan; ash flow; lava dome; volcanic ash; volcanic eruption https://www.scopus.com/inward/record.uri?eid=2-s2.0-0032865221&doi=10.1016%2fS0377-0273%2898%2900128-0&partnerID=40&md5=b24563729f0b63a2d9d96184149ca11d Cited by: 92 Tadahide Ui Norimichi Matsuwo Mari Sumita Akihiko Fujinawa article Yoshida1999303 In explosive magma eruptions, magma ascends through a conduit as a Poiseuille flow at depth, and gas exsolves gradually and expands as the pressure decreases (bubbly flow regime). When the volume fraction of gas becomes sufficiently large, liquid or solid parts of magma fragment into droplets or ashes, and the flow dynamics becomes governed by the gas phase (gas-ash flow regime). We propose a new flow regime, which we call fractured-turbulent flow regime, between the bubbly flow regime and the gas-ash flow regime. In the new regime, both liquid magma and gas are continuous phases. The high connectivity of the two phases allows the relative velocity between them to increase significantly. We present one sample calculation, which displays basically explosive characteristics, but has three features distinct from previous models. The explosive characteristics are manifested as the fragmentation of the magma and the high speed jet that issues from the vent. The first distinct feature is a nearly lithostatic pressure distribution, which results from the increase of the height of the fragmentation surface. The second one is the atmospheric pressure at the vent; the flow is not choked. The third one is that the relative velocity between the gas and the ash is large at the vent despite the large interaction force between the two phases. The large relative velocity is established in the fractured-turbulent regime, and is maintained in the subsequent gas-ash flow regime. Article 1999 English 03770273 10.1016/S0377-0273(99)00005-0 Journal of Volcanology and Geothermal Research 89 303 – 315 1-4 explosive volcanism; magmatism; two phase flow; volcanic eruption https://www.scopus.com/inward/record.uri?eid=2-s2.0-0032839904&doi=10.1016%2fS0377-0273%2899%2900005-0&partnerID=40&md5=ff9a8c04920b1996658931e8c7f701c7 Cited by: 32 Shigeo Yoshida Takehiro Koyaguchi article Colwell1999189 Microbial cell distribution in sediment core samples from the JAPEX/JNOC/GSC Mallik 2L-38 gas hydrate research well on the Mackenzie Delta (Canada) was studied using acridine orange direct counts of stained cells for total cell estimation, and by most probable number statistical enumeration for culturable methanogens. The purpose was to characterize the microbial communities in gas-hydrate-bearing sediments. Results indicated that the total cell count values were in the range of 1.1 × 105 cells/g to 2.8× 106 cells/g with culturable methanogens present at 1×10-4% to 1.0% of those values. These results also indicated that culturable methanogens may be more numerous in the porous sandy strata of the Mackenzie Bay Sequence than in clay and silt units of the Kugmallit Sequence. These data expand the known distribution of methanogens in deep sediments and establish the presence of microbial communities in subpermafrost environments. 1999 English 00687626 Bulletin of the Geological Survey of Canada 189-195 Biotechnologies Department, Idaho National Engineering and Environmental Laboratory, P.O. Box 1625, Idaho Falls, ID 83415-2203, United States 544 https://www.scopus.com/inward/record.uri?eid=2-s2.0-27844592645&partnerID=40&md5=6fc38e28c2995fca4d7c6c1e1627173d cited By 7 F.S. Colwell article Tulk1999251 Gas hydrate samples from the JAPEX/JNOC/GSC Mallik 2L-38 gas hydrate research well were analyzed on both macroscopic and molecular scales using several complementary experimental techniques. These included gas volume analysis, thermogravimetric analysis, precision gas analysis, powder X-ray diffraction, differential scanning calorimetry, Fourier transform infrared spectroscopy, and Raman Spectroscopy. Powder X-ray diffraction indicated that the samples were Structure I gas hydrate. Enclathrated gas species were identified to be mostly methane (98-100%); however, some samples contained significant amounts of heterogeneously dispersed propane and carbon dioxide (at least 1.5-2.0%). These samples were found to be significantly more stable than samples containing methane only. In addition, Raman spectra indicate subtle variations in the cage occupancies of the mixed gas hydrate as compared to those in pure methane hydrate. 1999 English 00687626 Bulletin of the Geological Survey of Canada 251-262 Steacie Institute for Molecular Sciences, National Research Council of Canada, 100 Sussex Drive, Ottawa, Ont. K1A 0R6, Canada 544 https://www.scopus.com/inward/record.uri?eid=2-s2.0-27844433540&partnerID=40&md5=34a9c966a1c929b29edbcca47f8171e3 cited By 18 C.A. Tulk article Yuretich1999588 Lake Baikal, in south-central Siberia, has been the focus of an international effort (the Baikal Drilling Project; BDP) to obtain continuous long cores (upwards of 100 m) from this unique rift-valley lake and to interpret the paleoclimatic history from various proxy data. As part of this effort, the clay minerals were examined by two research teams. A consistent clay-mineral assemblage, containing illite, inter-stratified illite-smectite, chlorite, and kaolinite as the major minerals, characterizes much of the modern sediments. The relative abundance of these minerals changes with depth in both short piston cores from various parts of the lake and in 100-m-long cores taken from the distal toe of the Selenga Delta (BDP-93). Independent analyses of the abundance changes and correlation with other data from the cores show that the clays are responding to two influences: (1) climatic fluctuations, particularly in the upper 40 m of the sedimentary record, which show the relative amount of illite-smectite (and sometimes kaolinite) increasing during warmer climate episodes, and (2) source-area changes, which are most evident below 40 m in the BDP-93 cores and mark a shift from an eastern (Buguldeika River) to a western (Selenga River) source. The clay-mineral-based climate fluctuations are correlative with the marine oxygen-isotope record through stage 7, and provide a relatively simple and cost-effective tool for gaining insight into the paleoclimate of this interior continental site. Article 1999 English 15271404 10.1306/D4268A45-2B26-11D7-8648000102C1865D Journal of Sedimentary Research 69 588 – 596 3 Russian Federation; clay mineral; proxy climate record; stratigraphic correlation https://www.scopus.com/inward/record.uri?eid=2-s2.0-0002809861&doi=10.1306%2fD4268A45-2B26-11D7-8648000102C1865D&partnerID=40&md5=befff1a4e0ebe60aa1ea8a244385d596 Cited by: 47 Richard Yuretich Martin Melles Brenn Sarata Hannes Grobe article Watanabe199995 Fugen-dake, the main peak of Unzen Volcano, began a new eruption sequence on November 17, 1990. On May 20, 1991, a new lava dome appeared near the eastern edge of the Fugen-dake summit. Small-scale, 104-106 m3 in volume, Merapi-type block and ash flows were frequently generated from the growing lava dome during May-June, 1991. These pyroclastic flows were accompanied by co-ignimbrite ash plumes that deposited ash-fall deposits downwind of the volcano. Three examples of co-ignimbrite ash-fall deposits from Unzen pyroclastic flows are described. The volume of fall deposits was estimated to be about 30% by volume of the collapsed portions of the dome that formed pyroclastic flows. This proportion is smaller than that described for other larger co-ignimbrite ash-fall deposits from other volcanoes. Grain size distributions of the Unzen co-ignimbrite ash-fall deposits are bi-modal or tri-modal. Most ashes are finer than 4 phi and two modes were observed at around 4-7 phi and 9 phi. They are composed mainly of groundmass fragments. Fractions of another mode at around 2 phi are rich in crystals derived from dome lava. Some of the fine ash component fell as accretionary lapilli from the co-ignimbrite ash cloud indicating either moisture or electrostatic aggregation. We believe that the co-ignimbrite ash of Unzen block and ash flows were formed by the mechanical fracturing of the cooling lava blocks as they collapsed and moved down the slope. These ashes were entrained into the convective plumes generated off the tops of the moving flows. Article 1999 English 03770273 10.1016/S0377-0273(98)00126-7 Journal of Volcanology and Geothermal Research 89 95 – 112 1-4 Japan; ash flow; ignimbrite; pyroclastic flow; volcanic ash; volcanic eruption https://www.scopus.com/inward/record.uri?eid=2-s2.0-0032840564&doi=10.1016%2fS0377-0273%2898%2900126-7&partnerID=40&md5=fd9ef553e578da73aa28de610fa49b33 Cited by: 30 Kazunori Watanabe Koji Ono Keiichi Sakaguchi Akira Takada Hideo Hoshizumi article Yamashina199943 Tilt observations at FG1 station located about 680 m west of the central crater of Unzen volcano, southwestern Japan, revealed details about the process of magma ascent during the mid-May 1991 crisis, just before the appearance of a lava dome. Crustal deformations measured during this period can be interpreted by a combination of upward growth of a buried magma column and lateral intrusion of a dike, modeled by a vertical line source and a planer tensile dislocation in an elastic half space. Marked change in tilt was observed at first in the EW direction at FG1 during May 11-14, suggesting the ascent of a magma column with a diameter of about 40 m from about 300 m to 160 m in depth beneath the central crater. After the interruption of the rise of the magma column, magma began to intrude laterally as a dike on May 15 toward approximately the N80°W direction. This resulted in a large tilt change essentially in the NS component at FG1. The horizontal extent of the dike might have exceeded 400 m in a few days with a thickness of about 6 m. On May 17, the magma column started to rise again, probably because the impediment to magma ascent was fractured by the growth of the dike. The top of the magma column finally reached to the crater bottom probably on May 19, and a new lava dome was actually observed on May 20. After which, the remarkable upward tilt to the south at FG1 due to the dike intrusion decreased rapidly. The deformation after May 20 can be interpreted by a gradual increase in the thickness of the dike up to 13 m by the end of May 1991. Although large errors are inevitable in estimated values because of a lack of sufficient data, the present results confirm the importance of making continuous observations of crustal deformation near the summit areas of active volcanoes in order to clarify the underground processes of magma movement leading to eruptions. Article 1999 English 03770273 10.1016/S0377-0273(98)00121-8 Journal of Volcanology and Geothermal Research 89 43 – 55 1-4 Japan; crustal deformation; dacite; lava dome; tilt; volcanic eruption https://www.scopus.com/inward/record.uri?eid=2-s2.0-0032817016&doi=10.1016%2fS0377-0273%2898%2900121-8&partnerID=40&md5=57109987da8a64a63b068a28099e6f1d Cited by: 22 Ken'Ichiro Yamashina Hiroshi Shimizu article Collett1999295 The JAPEX/JNOC/GSC Mallik 2L-38 gas hydrate research well project was designed to investigate the occurrence of in situ natural gas hydrate in the Mallik area of the Mackenzie Delta of Canada. Because gas hydrate is unstable at surface pressure and temperature conditions, a major emphasis was placed on the downhole logging program to determine the in situ physical properties of the gas-hydrate-bearing sediments. Downhole logging tool strings deployed in the Mallik 2L-38 well included the Schlumberger Platform Express with a high resolution laterolog, Array Induction Imager Tool, Dipole Shear Sonic Imager, and a Fullbore Formation Microlmager. The downhole log data obtained from the log- and core-inferred gas-hydrate-bearing sedimentary interval (897.25-1109.5 m log depth) in the Mallik 2L-38 well is depicted in a series of well displays. Also shown are numerous reservoir parameters, including gas hydrate saturation and sediment porosity log traces, calculated from available downhole well-log and core data. The gas hydrate accumulation delineated by the Mallik 2L-38 well has been determined to contain as much as 4.15109 m3 of gas in the 1 km2 area surrounding the drill site. 1999 English 00687626 Bulletin of the Geological Survey of Canada 295-311 United States Geological Survey, Denver Federal Center, MS-939, Denver, CO 80225, United States 544 https://www.scopus.com/inward/record.uri?eid=2-s2.0-27844510454&partnerID=40&md5=33b2f6f39c2a3bc8b7e99216a1656781 cited By 55 T.S. Collett article Kurita199977 Sparse occurrences of organic-walled dinoflagellate cysts were recorded from the JAPEX/JNOC/GSC Mallik 2L-38 gas hydrate research well, Mackenzie Delta area, Northwest Territories, Canada. Some of the recorded taxa are indicative of a Paleocene-Eocene age, while others are considered to be of Cretaceous origin. Because the deepest parts of the section are correlated to the Oligocene Kugmallit Sequence, all the dinoflagellate cysts are interpreted to be reworked. According to this interpretation, the total absence of in situ marine dinoflagellate cysts suggests that the studied samples were deposited under nonmarine conditions, most likely within a fluvial system. 1999 English 00687626 Bulletin of the Geological Survey of Canada 77-80 JAPEX Research Center, Japan Petroleum Exploration Company, Ltd., 1-2-1 Hamada, Mihama-ku, Chiba 261-0025, Japan 544 Dinophyceae https://www.scopus.com/inward/record.uri?eid=2-s2.0-27844487946&partnerID=40&md5=0daa92bf1d9e828af25d221a4a0d4aff cited By 4 H. Kurita article Uchida1999269 Core samples from the JAPEX/JNOC/GSC Mallik 2L-38 gas hydrate research well contained a variety of forms of gas hydrate within sands and granular sands in the interval from 896 to 926 m. A number of these samples were placed inside pressure vessels charged with nitrogen gas and subsequently transported to Japan for specialized dissociation experiments. X-Ray CT images were acquired, at constant intervals, from a granular sand (collected from 913.76 m) containing pore-space gas hydrate during warming from -35 to 4°C, and subsequently during stepped decreases in cell pressures (0.1 MPa) below assumed threshold stability conditions. Dissociated gas flow and sample temperatures were monitored continuously. Changes in CT values indicated that gas hydrate dissociated simultaneously, both on the exposed surfaces and within the pore spaces of the sample, in response to pressure changes. This suggested that pressure reductions were effectively transmitted through the sample, most likely because the samples were not fully saturated with gas hydrate. Gas-flow measurements indicated that a larger pressure drawdown caused a higher dissociation rate. 1999 English 00687626 Bulletin of the Geological Survey of Canada 269-279 JAPEX Research Center, Japan Petroleum Exploration Company, Ltd., 1-2-1 Hamada, Mihama-ku, Chiba 261-0025, Japan 544 https://www.scopus.com/inward/record.uri?eid=2-s2.0-0008565866&partnerID=40&md5=b6af3bc7c04c228cb2b964774dff3653 cited By 1 T. Uchida article Ohara199919 The JAPEX/JNOC/GSC Mallik 2L-38 gas hydrate research well, located in the Mackenzie Delta, Northwest Territories, Canada, was completed to 1150 m on March 30, 1998, after 39 days. Operations were undertaken through a collaborative agreement between the Japan National Oil Corporation and the Geological Survey of Canada. Research goals included evaluation of engineering technologies used to drill and core gas-hydrate-bearing strata. Eight coring runs were conducted within the permafrost interval (0-640 m) in a surface hole drilled to 687 m. Subsequently, a 340 mm surface casing was installed and the main hole was advanced to a depth of 1150 m with 16 coring runs. A cooled (∼2°C) KCl/polymer drilling mud and Drilltreat, a chemical mud additive, successfully stabilized gas hydrate within cores and formation sediments. No serious hole problems, accidents, or mishaps occurred; however, delays caused by adverse weather and mechanical problems caused cancellation of planned production testing. Coring in the main hole was successful, allowing the evaluation of four different core barrels. Gas-hydrate-bearing cores were collected in a variety of sediments between 896 and 952 m. 1999 English 00687626 Bulletin of the Geological Survey of Canada 19-30 Japan Petroleum Exploration Company, Ltd. (JAPEX), 2-2-20 Higashi-shinagawa, Shinagawa-ku, Tokyo 140-0002, Japan 544 https://www.scopus.com/inward/record.uri?eid=2-s2.0-0012094322&partnerID=40&md5=129c8db5c6299e87a7cc953b9f830580 cited By 5 T. Ohara article Wright1999101 During drilling of the JAPEX/JNOC/GSC Mallik 2L-38 gas hydrate research well, core temperatures were measured immediately upon recovery in the core-logging trailer. Gas-hydrate-bearing cores were typically frozen, with temperatures as much as 6°C lower than cores containing no gas hydrate. This temperature depression is attributed to the endothermic dissociation of gas hydrate during uphole tripping, and can be used to estimate minimum in situ gas hydrate saturation. Numerical modelling of heat exchange between core and circulating mud during tripping demonstrates that cores cool to mud temperature before leaving the methane hydrate P-T stability field. Simple arguments support the hypothesis that the endothermic heat of gas hydrate dissociation is supplied largely by the release of latent heat during coincident freezing of pore waters. Assuming minimal heat exchange with circulating mud, energy-balance calculations yield estimates of the quantity of gas hydrate lost to dissociation during recovery. These estimates are comparable to the in situ gas hydrate concentrations inferred from downhole geophysical logs. 1999 English 00687626 Bulletin of the Geological Survey of Canada 101-108 Geological Survey of Canada, 601 Booth Street, Ottawa, Ont. K1A 0E8, Canada 544 https://www.scopus.com/inward/record.uri?eid=2-s2.0-0012094323&partnerID=40&md5=9db6a21346ae152cf84e6dd84a366210 cited By 8 J.F. Wright article Lorenson1999143 Molecular and isotopic composition of gases from the JAPEX/JNOC/GSC Mallik 2L-38 gas hydrate research well demonstrate that the in situ gases can be divided into three zones composed of mixtures of microbial and thermogenic gases. Sediments penetrated by the well are thermally immature; thus the sediments are probably not a source of thermogenic gas. Thermogenic gas likely migrated from depths below 5000 m. Higher concentrations of gas within and beneath the gas hydrate zone suggest that gas hydrate is a partial barrier to gas migration. Gas hydrate accumulations occur wholly within zone 3, below the base of permafrost. The gas in gas hydrate resembles, in part, the thermogenic gas in surrounding sediments and gas desorbed from lignite. Gas hydrate composition implies that the primary gas hydrate form is Structure I. However, Structure II stabilizing gases are more concentrated and isotopically partitioned in gas hydrate relative to the sediment hosting the gas hydrate, implying that Structure II gas hydrate may be present in small quantities. 1999 English 00687626 Bulletin of the Geological Survey of Canada 143-163 United States Geological Survey, MS-999, 345 Middlefield Road, Menlo Park, CA 94025, United States 544 https://www.scopus.com/inward/record.uri?eid=2-s2.0-14044272606&partnerID=40&md5=8048c0efb1458ee0465972001165626d cited By 33 T.D. Lorenson article Lee1999313 The amount of in situ gas hydrate concentrated in the sediment pore space at the JAPEX/JNOC/GSC Mallik 2L-38 gas hydrate research well was estimated by using compressional-wave (P-wave) and shear-wave (S-wave) downhole log measurements. A weighted equation developed for relating the amount of gas hydrate concentrated in the pore space of unconsolidated sediments to the increase of seismic velocities was applied to the acoustic logs with porosities derived from the formation density log. A weight of 1.56 (W=1.56) and the exponent of 1 (n=1) provided consistent estimates of gas hydrate concentration from the S-wave and the P-wave logs. Gas hydrate concentration is as much as 80% in the pore spaces, and the average gas hydrate concentration within the gas-hydrate-bearing section from 897 m to 1110 m (excluding zones where there is no gas hydrate) was calculated at 39.0% when using P-wave data and 37.8% when using S-wave data. 1999 English 00687626 Bulletin of the Geological Survey of Canada 313-322 United States Geological Survey, Denver Federal Center, MS-939, Denver, CO 80225, United States 544 https://www.scopus.com/inward/record.uri?eid=2-s2.0-0001273063&partnerID=40&md5=5e3ee895186159e800204c255a19b82a cited By 30 M.W. Lee article Hoshizumi199981 During the past 500 thousand years, Unzen volcano, an active composite volcano in the Southwest Japan Arc, has erupted lavas and pyroclastic materials of andesite to dacite composition and has developed a volcanotectonic graben. The volcano can be divided into the Older and the Younger Unzen volcanoes. The exposed rocks of the Older Unzen volcano are composed of thick lava flows and pyroclastic deposits dated around 200-300 ka. Drill cores recovered from the basal part of the Older Unzen volcano are dated at 400-500 ka. The volcanic rocks of the Older Unzen exceed 120 km3 in volume. The Younger Unzen volcano is composed of lava domes and pyroclastic deposits, mostly younger than 100 ka. This younger volcanic edifice comprises Nodake, Myokendake, Fugendake, and Mayuyama volcanoes. Nodake, Myokendake and Fugendake volcanoes are 100-70 ka, 30-20 ka, and <20 ka, respectively. Mayuyama volcano formed huge lava domes on the eastern flank of the Unzen composite volcano about 4000 years ago. Total eruptive volume of the Younger Unzen volcano is about 8 km3, and the eruptive production rate is one order of magnitude smaller than that of the Older Unzen volcano. Article 1999 English 03770273 10.1016/S0377-0273(98)00125-5 Journal of Volcanology and Geothermal Research 89 81 – 94 1-4 Japan; historical perspective; lava dome; pyroclastic flow; volcanic eruption https://www.scopus.com/inward/record.uri?eid=2-s2.0-0032842080&doi=10.1016%2fS0377-0273%2898%2900125-5&partnerID=40&md5=a9881a8328525b14c0957e14da29d627 Cited by: 75 Hideo Hoshizumi Kozo Uto Kazunori Watanabe article Clark1999177 Pore waters have been extracted from sediments in the permafrost interval (110-176 m) and the gas hydrate interval (886-952 m) of the JAPEX/JNOC/GSC Mallik 2L-38 drill core and analyzed for δ18O,δ2H, and geochemistry. Pore waters from the permafrost interval have δ18O values of -19.5 ± 0.5‰ (upper permafrost) and -23.1 ± 1.0‰ (lower permafrost) indicating the likely origin to be local, contemporary meteoric waters infiltrating these sediments during a period of subaerial exposure. Pore waters in the subpermafrost gas hydrate zone are isotopically depleted from seawater values, with δ18O ranging between -14‰ and -8‰c. A weak correlation between δ18O and Cl- exists in the gas-hydrate-bearing sands, consistent with the combined effect of isotopic depletion during gas hydrate formation, and enrichment associated with gas hydrate decomposition. The upper silt and deeper clayey silt sections also retain a minor correlation between isotopes and Cl-, and show strong variability in both δ18O and Cl- with depth, suggesting a history of gas hydrate formation, decomposition, and fluid migration. The Cl--δ18O relationships demonstrate that the original pore waters are a mixture of seawater with greater than 50% meteoric water. 1999 English 00687626 Bulletin of the Geological Survey of Canada 177-188 Ottawa-Carleton Geoscience Centre, Department of Earth Sciences, University of Ottawa, 140 Louis Pasteur Street, Ottawa, Ont. K1N 6N5, Canada 544 https://www.scopus.com/inward/record.uri?eid=2-s2.0-27844553844&partnerID=40&md5=3474a6f6444f4e6edd05e9abf4d257d3 cited By 0 I.D. Clark article Snowdon1999125 Optimized, first-order, discrete Arrhenius kinetic parameters have been determined for the thermogenic generation of methane and carbon dioxide for several low-maturity, organic-rich core samples from the JAPEX/JNOC/GSC Mallik 2L-38 gas hydrate research well. Pyrolysis was carried out using a thermogravimetric analyzer heated at 10, 25, and 50°C/min. The specific products were detected using a directly coupled Fourier Transform Infrared spectrometer. Results indicated that at typical geological heating rates of 3°C/Ma, significant (about 10% of the total) thermogenic carbon dioxide was released at very low temperatures (<60°C) and would be coproduced with microbiologically mediated, diagenetic carbon dioxide. At the same geological heating rate, the first 10% of thermogenic methane was determined to have been released between about 110 and 140°C while significant methane generation from the kerogen continued beyond 250°C. The absolute kinetic parameters for methane indicate that below about 60°C essentially no thermogenic methane should be expected. Thus no in situ thermogenic methane should be expected in the Mallik 2L-38 well. 1999 English 00687626 Bulletin of the Geological Survey of Canada 125-141 Geological Survey of Canada (Calgary), 3303-33 Street N.W., Calgary, Alta. T2L 2A7, Canada 544 https://www.scopus.com/inward/record.uri?eid=2-s2.0-27844609316&partnerID=40&md5=adba0d801c58bd0e57867daf9e682333 cited By 3 L.R. Snowdon article Kagiyama199935 The resistivity structure of Unzen Volcano has been revealed by extensive magnetotelluric surveys since the first eruption on November 17, 1990. This structure comprises a highly resistive surface layer, a low-resistive second layer at several hundred meters depth, interpreted as a water-saturated layer, a resistive third layer, and a low-resistive fourth layer at 10 km depth, possibly related to the deep magmatic activity. The structure has influenced the volcanic activity of Unzen. This activity was characterized by a series of dramatic changes in eruption type: a minor phreatic eruption on November 17, 1990; phreatic eruptions after February 12, 1991, preceded by several weeks of volcanic tremor; phreatomagmatic eruptions after April 9, and dome effusion beginning May 19, 1991. This paper presents a hypothesis in which the top of the magma column rose about 20 m/day, reached the base of the water-saturated layer at the end of January, 1991, and approached the upper boundary of this layer on April 9. Thus, the temporal change of eruption type and associated phenomena are systematically explained by an interaction between magma and groundwater contained in the saturated layer. Article 1999 English 03770273 10.1016/S0377-0273(98)00120-6 Journal of Volcanology and Geothermal Research 89 35 – 42 1-4 Japan; magmatism; phreatomagmatism; resistivity; volcanic eruption https://www.scopus.com/inward/record.uri?eid=2-s2.0-0032819102&doi=10.1016%2fS0377-0273%2898%2900120-6&partnerID=40&md5=a5a70f37b9fab80c5f52696ffe614999 Cited by: 58 T. Kagiyama H. Utada T. Yamamoto article sackett1999long 1999 10.3133/ofr99158 US Geological Survey US Geological Survey 99-158 378 Penelope C Sackett Vicki S McConnell Angela L Roach Susan S Priest John H Sass article Kaneko199957 We analyse shortwave infrared thermal data of the phase 1 eruption of Unzen Volcano (Japan) extracted from eight nighttime Thematic Mapper (TM) images taken from the Landsat 5 satellite between October 1991 and November 1992. We identify two discrete regions of the dome that were heated to high temperature by the ongoing eruptive activity; a fumarolically heated region and an area associated with the effusion of new lava. We concentrate analysis on the fumarolically heated region and investigate the relationships between parameters derived from the infrared radiance data and the nature of the fumarolic gas and magma fluxes. Temporal variations in the parameters derived from the radiance data closely follow those observed in the measured rate of magma effusion. The positive correlation observed between the fumarolically driven shortwave infrared flux and the magma discharge rate (r2 = 0.64) indicates that degassing occurred efficiently and in proportion to the amount of magma supplied. Over our monitoring period, the data suggest that gas accumulation within the edifice did not occur, this conclusion agreeing with a previous finding obtained using correlation spectrometer (COSPEC) analysis of SO2 flux rates. A positive correlation (r2 = 0.56) was also found between the mean radiance of the pixels in the fumarolically heated region and the overall size of that region. This suggests a potential mechanism whereby, when gas pressure within the edifice increased, excess gas escaped through additional pathways to the surface as well through an increased flux at the main fumarolic vents. Article 1999 English 03770273 10.1016/S0377-0273(98)00122-X Journal of Volcanology and Geothermal Research 89 57 – 64 1-4 Japan; fumarole; Landsat thematic mapper; magma; volcanic eruption; volcanic gas https://www.scopus.com/inward/record.uri?eid=2-s2.0-0032839903&doi=10.1016%2fS0377-0273%2898%2900122-X&partnerID=40&md5=8c1be40d02eabeff2a12d67b21b535cf Cited by: 29 Takayuki Kaneko Martin J. Wooster article Laj199915317 Four hundred twenty five new paleointensity (Thellier-Thellier) determinations (out of 545 analyzed samples) have been obtained from core HSDP, which penetrates about 1000 meters (208 flows) of the Mauna Loa and Mauna Kea volcanic series encompassing the last 420 kyr. Rock magnetic investigations identify pseudo-single-domain magnetite as the main magnetic mineral. Inclinations are shallower than expected from a geocentric dipole field but are consistent with data from other geographical regions at the same latitude. The inclination record reveals three episodes of negative inclination whose interpolated age correlates well with that of known geomagnetic events. The paleointensity record from the Mauna Loa sequence is not very detailed and does not allow precise comparison with other data in the 0-50 kyr interval. The record from the Mauna Kea sequence, on the contrary, is very detailed and documents relatively short-lived episodes of low and high field strength from 15 to 60 μT. The average virtual dipole moment (8.7 ± 3.0 1022 A.m2) is not significantly different from the value reported by Kono and Tanaka [1995] for the last 2.5 Myr. A comparison with other data from Hawaii and other geographical regions is described in detail. There are no drastic changes in paleointensity with the inclination anomaly, in agreement with previous results from Hawaii but in contrast with most published results which, however, consider data from polarity transition. Spectral analysis of a particularly detailed portion of the record, between 420 and 326 kyr, documents significant periodicities at 36, 8, 5, and 4 ka in the inclination record but not in the intensity record, suggesting that changes in time of the inclination are to a certain extent independent from those of the intensity. Copyright 1999 by the American Geophysical Union. 1999 English 21699313 10.1029/1999jb900113 Journal of Geophysical Research: Solid Earth 104 Blackwell Publishing Ltd 15317-15338 Lab. Sci. Climat de l'Environnement, CEA-CNRS, Gif-sur-Yvette, France; Lab. Sci. Climat de l'Environnement, CEA-CNRS, 91198 Gif-sur-Yvette Cedex, France B7 magnetic intensity; paleomagnetism; Quaternary, Hawaii; United States https://www.scopus.com/inward/record.uri?eid=2-s2.0-0032698529&doi=10.1029%2f1999jb900113&partnerID=40&md5=60f205c3654e5198a1c9ddf4c7976c5c cited By 38 C. Laj C. Kissel article Watanabe1999113 Fugen-dake, the main peak of Unzen volcano, began to erupt on 17 November 1990 after 198 years of dormancy. Following a period of steam-dominated tephra eruptions, a new lava dome appeared at the bottom of Jigokuato Crater in the summit region on 20 May 1991. Non-hydrated vesiculated glass was detected in the precursory tephra eruptions, beginning 12 February 1991. Determination of whether glass pyroclasts are hydrated or not appears to be an effective means of ascertaining whether the tephra contains juvenile material from ascending magma. The detection of juvenile pyroclasts at Fugen-dake more than 3 months before the appearance of the lava dome suggests that monitoring of early tephra emissions is an effective way to help forecast impending magmatic eruptions. Article 1999 English 03770273 10.1016/S0377-0273(98)00127-9 Journal of Volcanology and Geothermal Research 89 113 – 121 1-4 Japan; lava dome; magma chemistry; volcanic eruption; volcanic glass https://www.scopus.com/inward/record.uri?eid=2-s2.0-0032838558&doi=10.1016%2fS0377-0273%2898%2900127-9&partnerID=40&md5=ff2da1b9b40b686b38fb17451dd7c79d Cited by: 23 Koichiro Watanabe Tohru Danhara Kazunori Watanabe Kunihisa Terai Tohru Yamashita article Wright1999229 This paper summarizes laboratory determinations of the pressure-temperature (P-T) phase equilibrium conditions for methane hydrate stability in sediments recovered from the gas-hydrate-bearing interval at JAPEX/JNOC/GSC Mallik 2L-38 gas hydrate research well. Three test samples consisted of quartz-rich sand with in situ pore-water salinities of 4 ppt (parts per thousand), 20 ppt, and 40 ppt. A fourth sample was dominated by silt, with a salinity of 31 ppt. Initially, methane hydrate was regrown in the sediments, followed by the determination of P-T stability thresholds between 0°C and 12°C. Comparisons with published data for methane hydrate stability in pure gas-water systems indicate no appreciable shift in P-T stability conditions in sand with salinity of 4 ppt, but suggest a progressively increasing shift towards the higher pressure, lower temperature region for sand samples with elevated salinity. Test results for the saline silt sample indicate an additional shift in the stability threshold attributed to the effect of the porous medium in fine-grained sediments. 1999 English 00687626 Bulletin of the Geological Survey of Canada 229-240 Geological Survey of Canada, 601 Booth Street, Ottawa, Ont. K1A 0E8, Canada 544 https://www.scopus.com/inward/record.uri?eid=2-s2.0-0011601423&partnerID=40&md5=f32958f978a12aea1e07000fdd349550 cited By 29 J.F. Wright article Schmid1999266 During the Triassic collision of the Yangtze and Sino-Korean cratons, the leading edge of the Yangtze crust subducted to mantle depths and was subsequently exhumed as a penetratively deformed, coherent slab capped by a normla shear zone. This geometry requires a reverse shear zone at the base of the slab, and we suggest that the Yangtze foreland fold-and-thrust belt constitutes this zone. Lower Triassic rocks of the eastern foreland record NW-SE compression as the oldest compressional stress field; onset of related deformation is indicated by Middle Triassic clastic sedimentation. Subsequent Jurassic stress fields show a clockwise change of compression directions. Based on nearly coeval onset and termination of deformation, and on a common clockwise change in the principal strain/stress directions, we propose that the foreland deformation was controlled by the extrusion of the ultra high-pressure slab. Widespread Cretaceous-Cenozoic reactivation occurred under regional extension to transtension, which characteristically shows a large-scale clockwise change of the principal extension directions during the Lower Cretaceous. Article 1999 English 09544879 10.1046/j.1365-3121.1999.00254.x Terra Nova 11 Blackwell Publishing Ltd. 266 – 272 6 China; Dabie Shan; collision zone; crustal deformation; exhumation; fold and thrust belt; foreland basin; subduction; Triassic https://www.scopus.com/inward/record.uri?eid=2-s2.0-0033303257&doi=10.1046%2fj.1365-3121.1999.00254.x&partnerID=40&md5=2e95eb166599040245f8679a94db07a6 Cited by: 57 J.C. Schmid L. Ratschbacher B.R. Hacker I. Gaitzsch S. Dong article Duchkov1999287 Data on the geotemperature field of the central part of the Baikal Rift Zone (BRZ) and adjacent regions of the Siberian Platform and Transbaikalia are summarized. About 800 measurements of heat flow were made here, 700 of them were carried out in the Baikal basin (shallow-depth measurements in the upper layer of sediments). The average heat flow through the Baikal bottom is 71±21 mW/m2. At some sites of the bottom extremely high flows (up to 6000-8000 mW/m2) confined to the local centers of discharge of underwater sources have been revealed. In the montane framing of the rift troughs heat flow is much less intense - no more than 15-40 mW/m2. In the south of the Siberian Platform and in Transbaikalia average heat flow is 40±9 and 52±11 mW/m2, respectively. This differentiated heat flow distribution in the BRZ is, probably, the result of active water exchange in intermount artesian basins, which leads to cooling of feeding zones (mountain ridges) by meteogenic waters and further warming-up of the sedimentary cover of these basins (discharge areas). Special studies in the North-Muya tunnel supported this hypothesis. The validity of numerous shallow-depth measurements of heat flow in Lake Baikal is corroborated by the temperatures measured in the first underwater boreholes BDP-93 and BDP-96. By the location of the lower boundary of the gas hydrate layer of the Baikal sediments, 500 estimates of heat flow in the Southern and Central basins were made. In accordance roith these estimates, average heat flow is 76±10 mW/m2, which also corroborates the above average heat flow value. Heat flow data were used to forecast deep temperatures by the geothermal method. The paper analyzes the forecast temperature distributions at depths of 10, 20, 30, and 40 km. The validity of a geothermal forecast for the rift troughs is corroborated by the results of thermobarometric study of mineral inclusions from deep-seated volcanites of East Sayan and the Vitim Plateau. These data also evidence that heat flow and deep temperatures within the BRZ are underestimated. Article 1999 Russian 00167886 Geologiya i Geofizika 40 287 – 303 3 https://www.scopus.com/inward/record.uri?eid=2-s2.0-0000226202&partnerID=40&md5=a20693245e0c69213ab1de98313c4f5e Cited by: 16 A.D. Duchkov S.V. Lysak V.A. Golubev R.P. Dorofeeva L.S. Sokolova article Sato1999197 Pargasite commonly occurs in the dacitic groundmass of the 1991-1995 eruption products of Unzen volcano. We described the occurrence and chemical compositions of amphibole in the dacite, and also carried out melting experiments to determine the low-pressure stability limit of amphibole in the dacite. The 1991-1995 ejecta of the Unzen volcano show petrographic evidence of magma mixing, such as reverse compositional zoning of plagioclase and amphibole phenocrysts, and we used a groundmass separate as a starting material for the experiments. Reversed experiments show that the maximum temperature for the crystallization of amphibole is 930°C at 196 MPa, 900°C at 98 MPa, and 820°C at 49 MPa. Compared with the experimental results on the Mount St. Helens dacite, present experiments on the Unzen dacitic groundmass show that amphibole is stable to pressures ca. 50 MPa lower at 850°C. Available Fe-Ti oxide thermometry indicates the crystallization temperature of the groundmass of the Unzen dacite to be 880 ± 30°C, suggesting that the groundmass pargasite crystallized at > 70 MPa, corresponding to a depth of more than 3 km in the conduit. The chlorine content of the groundmass pargasite is much lower than that of phenocrystic magnesiohornblende in the 1991-1995 dacite of Unzen volcano, indicating that vesiculation/degassing of magma took place before the crystallization of the groundmass pargasite. The present study shows that the magma was water oversaturated and that the degassing of magma along with magma mixing caused crystallization of the groundmass amphibole at depths of more than 3 km in the conduit. Article 1999 English 03770273 10.1016/S0377-0273(98)00132-2 Journal of Volcanology and Geothermal Research 89 197 – 212 1-4 Japan; crystallization; dacite; pargasite; volcanic eruption https://www.scopus.com/inward/record.uri?eid=2-s2.0-0032868174&doi=10.1016%2fS0377-0273%2898%2900132-2&partnerID=40&md5=4300f1c3eb73e4dcd09f8f4d02da4295 Cited by: 73 Hiroaki Sato Setsuya Nakada Toshitsugu Fujii Michihiko Nakamura Keiko Suzuki-Kamata article Yamashina199965 Ground temperature associated with eruptive activity of Unzen Volcano, southwestern Japan, was observed in a cave about 680 m west of the central vent. Based on the data during 1991-1996, eliminating the effects of seasonal change, the temperature rose to the highest level probably around the first half of 1992. Hereafter the temperature decreased gradually year by year at least up to the autumn of 1996, beyond the level recovered at the beginning of the lava extrusion in May 1991. Although it is not necessarily conclusive, the present observation suggests a possible rise in ground temperature prior to the commencement of the first phreatic eruption in November 1990. If so, a careful observation may help to predict future eruptions by detecting a precursory rise of the ground temperature in this volcano. Article 1999 English 03770273 10.1016/S0377-0273(98)00123-1 Journal of Volcanology and Geothermal Research 89 65 – 71 1-4 Japan; prediction; surface temperature; volcanic eruption https://www.scopus.com/inward/record.uri?eid=2-s2.0-0032817285&doi=10.1016%2fS0377-0273%2898%2900123-1&partnerID=40&md5=7422e1107518bda6bb31ee9593982175 Cited by: 4 Ken'Ichiro Yamashina Takeshi Matsushima article Nishi199923 Global positioning system (GPS) measurements made around Unzendake volcano, Kyushu, Japan, since January 1991 have detected ground deformation caused by magma intrusion and lava discharge. In the intermittent phreatic and phreatomagmatic eruption stage, the ground was inflating. After growth of the lava dome and following frequent pyroclastic flows at Unzendake volcano, the ground began deflating. These ground deformations are explained by the inflation and deflation of a Mogi's source model (a point source model) located about 6 km west of the active crater at a depth of 11 km, at an aseismic region. The observed horizontal displacement vectors pointed radially away from the estimated pressure source during inflation and pointed to the pressure source during deflation. The horizontal displacements at the reference GPS station calculated from contraction of the estimated pressure source coincide well with the actual horizontal displacements observed from other GPS baseline systems. These observations validate our estimates for the pressure source. Based on the relation between the deformation volume of the ground surface and the discharged volume of the lava, it is estimated that during the eruption there was magma supply from the deeper portion as well as magma discharge at the crater. Magma is estimated to be supplied to the reservoir at an average rate of 1.1 x 105 m3/day; magma intrusion began in December 1989 at the latest and continued for 1.9 x 103 days. Article 1999 English 03770273 10.1016/S0377-0273(98)00119-X Journal of Volcanology and Geothermal Research 89 23 – 34 1-4 Japan; crustal deformation; GPS; ground motion; lava flow; magmatism; volcanic earthquake; volcanic eruption https://www.scopus.com/inward/record.uri?eid=2-s2.0-0032840563&doi=10.1016%2fS0377-0273%2898%2900119-X&partnerID=40&md5=f84c7b3e30c9c82e47dcb474eed16107 Cited by: 38 K. Nishi H. Ono H. Mori article Sass199843 In December 1997, the California Energy Commission (CEC) agreed to provide funding for Phase III continued drilling of the Long Valley Exploratory Well (LVEW) near Mammoth Lakes, CA, from its present depth. The CEC contribution of $1 million completes a funding package of $2 million from a variety of sources, which will allow the well to be cored continuously to a depth of between 11,500 and 12,500 feet. The core recovered from Phase III will be crucial to understanding the origin and history of the hydrothermal systems responsible for the filling of fractures in the basement rock. The borehole may penetrate the metamorphic roof of the large magmatic complex that has fed the volcanism responsible for the caldera and subsequent activity. 1998 English 01607782 Bulletin. Geothermal Resources Council 27 Geothermal Resources Council, Davis, CA, United States 43-46 U.S. Geological Survey, Denver, United States 2 Costs; Exploratory boreholes; Geothermal wells; Project management, Exploratory wells, Core drilling https://www.scopus.com/inward/record.uri?eid=2-s2.0-0032026104&partnerID=40&md5=9db2f5194509bae1a9f5d5a09629f311 cited By 0 John Sass John Finger Vicki McConnel article Lassiter1998483 Isotopic heterogeneity in Hawaiian shield lavas reflects the presence of two distinct recycled components in the Hawaiian plume, both from the same packet of recycled oceanic lithosphere. Radiogenic Os-isotopes and anomalously heavy oxygen-isotopes in Koolau lavas reflect melt generation from recycled oceanic crust plus pelagic sediment. In contrast, Kea lavas have unradiogenic Os-isotopes but anomalously light oxygen-isotopes. Oxygen-osmium-lead isotope correlations preclude generation of the Kea isotopic signature from asthenospheric upper mantle or the in situ lithospheric mantle or crust. Instead, melting of recycled, hydrothermally altered ultramafic lower crust or lithospheric mantle in the Hawaiian plume can produce Kea-type lavas. The preservation of both upper- and lower-crustal oxygen isotope signatures in plume-derived Hawaiian lavas indicates that chemical heterogeneities with length scales of only a few kilometers can be preserved in the convecting mantle for long periods of time, probably on the order of 1 Ga or more. 1998 English 0012821X 10.1016/S0012-821X(98)00240-4 Earth and Planetary Science Letters 164 483-496 Department of Terrestrial Magnetism, Carnegie Institution of Washington, Washington, DC 20015, United States 3-4 hot spot; isotopic composition; oceanic crust; osmium, Pacific Ocean https://www.scopus.com/inward/record.uri?eid=2-s2.0-0032583369&doi=10.1016%2fS0012-821X%2898%2900240-4&partnerID=40&md5=e272776d5aa88b3114baec2f46cc8d6f cited By 341 J.C. Lassiter E.H. Hauri article https://doi.org/10.1029/98EO00326 The Long Valley caldera region, located between the Sierra Nevada and the Basin and Range Province in eastern California, encompasses a large volcanic complex whose eruptive history began nearly 4 m.y.a. and continues to the present, with eruptions occurring, on average, every few hundred years. Eruptive activity in the area occurred as recently as 250 years ago with small eruptions from vents on Paoha Island in the middle of Mono Lake and 550–600 years ago from three vents at the southern end of the Inyo volcanic chain in the west moat of Long Valley caldera. The current unrest in the caldera began in 1980 and has included recurring earthquake swarms and uplift of the resurgent dome in the center of the caldera by over 70 cm [Bailey and Hill, 1990]. Long Valley caldera is one of several large calderas around the world that have shown similar signs of magmatic unrest in the last few decades. 1998 https://doi.org/10.1029/98EO00326 Eos, Transactions American Geophysical Union 79 429-432 36 https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/98EO00326 David P. Hill Michael L. Sorey William L. Ellsworth John Sass article Hacker1998215 New SHRIMP and TIMS zircon ages, 40Ar/39Ar ages, and eclogite locations contribute significantly to our understanding of the ultrahigh-pressure Dabie Shan. (1) The geographic extent of the Yangtze craton that was subducted to ultrahigh pressure extends to the northern edge of the Dabie Shan. (2) The northern half of the Dabie Shan is a magmatic complex, intruded over a 10-Myr interval between 137 and 126 Ma, that accomodated ~100% N-S- stretching of the pre-existing collisional architecture. (3) Granitic orthogneisses and enclosing ultrahigh-pressure paragneisses have indistinguishable zircon populations. The population of Triassic zircon ages ranges from ~219 to ~245 Ma, leading us to question the prevailing assumption that 219 Ma zircons formed at ultrahigh pressure, and to propose instead that they reflect late retrogression at crustal pressures following the bulk of exhumation. Article 1998 English 0012821X 10.1016/S0012-821X(98)00152-6 Earth and Planetary Science Letters 161 Elsevier 215 – 230 1-4 China; geochronology; Triassic; ultrahigh pressure metamorphism https://www.scopus.com/inward/record.uri?eid=2-s2.0-0032465787&doi=10.1016%2fS0012-821X%2898%2900152-6&partnerID=40&md5=dc6610bc0398d08246fce2878c0edbdd Cited by: 1087 Bradley R. Hacker Lothar Ratschbacher Laura Webb Trevor Ireland Doug Walker Dong Shuwen inproceedings Wencai1997UnconformitylikeRP 1997 Yang Wencai article Yang1997100 This article provides a brief view of development of the Sulu ultrahigh pressure metamorphic (UHPM) terrane involved in a conceivable intracontinental collision between the Sion-Korean Plate and the Yangtze Plate during the Mesozoic Era. Integrated study of geological and geophysical data reveals crustal structures in the Sulu terrane, and provides evidence for an evolution model of the UHPM terrane called "the dual intracontinental subduction model". Article 1997 English 07053797 10.18814/epiiugs/1997/v20i2/006 Episodes 20 International Union of Geological Sciences 100 – 103 2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-0031286293&doi=10.18814%2fepiiugs%2f1997%2fv20i2%2f006&partnerID=40&md5=8d44aaec812e0ddf08dd39776afafb44 Cited by: 23; All Open Access, Hybrid Gold Open Access Wencai Yang article Colman19973 The Baikal Drilling Project (BDP) is a multinational effort to investigate the paleoclimatic history and tectonic evolution of the Baikal sedimentary basin during the Late Neogene. In March 1993 the Baikal drilling system was successfuly deployed from a barge frozen into position over a topographic high, termed the Buguldeika saddle, in the southern basin of Lake Baikal. The BDP-93 scientific team, made up of Russian, American and Japanese scientists, successfully recovered the first long (>100 m) hydraulic piston cores from two holes in 354 m of water. High quality cores of 98 m (Hole 1) and 102 m (Hole 2), representing sedimentation over the last 500,000 years, were collected in 78 mm diameter plastic liners with an average recovery of 72% and 90%, respectively. Magnetic susceptibility logging reveals an excellent hole-to-hole correlation. In this report the scientific team describes the preliminary analytical results from BDP-93 hole 1 cores. Radiocarbon dating by accelerator mass spectrometry provides an accurate chronology for the upper portion of Hole 1. Detailed lithologic characteristics, rock magnetic properties and inorganic element distributions show a significant change to the depositional environment occuring at 50 m subbottom depth, approximately 250,000 BP. This change may be due to uplift and rotation of the horst block in the Buguldeika saddle. The sedimentary section above 50 m is pelitic with varve-like laminae, whereas the section below 50 m contains a high proportion of sand and gravel horizons often organized into turbidite sequences. Accordingly, high resolution seismic records reveal a change in sonic velocity at this depth. It is inferred that sedimentation prior to 250 ka BP was from the west via the Buguldeika river system. After 250 ka BP the Buguldeika saddle reflects an increase in hemipelagic sediments admixed with fine-grained material from the Selenga River drainage basin, east of Lake Baikal. Variations in the spore-pollen assemblage, diatoms, biogenic silica content, rock magnetic properties, clay mineralogy and organic carbon in the upper 50 m of BDP-93-1 reveal a detailed record of climate change over approximately the last 250,000 years. These variables alternate in a pattern characteristic of glacial/interglacial climatic fluctuations. The present age model suggests that the climate signal recorded in Lake Baikal sediments is similar to Late Quaternary signals recorded in Chinese loess sections and in marine sediments. Copyright © 1996 INQUA/ Elsevier Science Ltd. Article 1997 English 10406182 10.1016/1040-6182(96)00027-4 Quaternary International 37 Elsevier Ltd 3 – 17 Russian Federation, Siberia, Lake Baikal, Buguldeika Saddle; borehole logging; palaeoclimate; sedimentation; tectonics https://www.scopus.com/inward/record.uri?eid=2-s2.0-0030928007&doi=10.1016%2f1040-6182%2896%2900027-4&partnerID=40&md5=36046262fdada2ba5749cd914efc9a2d Cited by: 57 S. Colman M. Grachev P. Hearn S. Horie T. Kawai N. Logachov V. Antipin V. Fialkov A. Gorigljad B. Tomilov B. Khakhaev S. Kochikov V. Lykov L. Pevzner A. Bucharov N. Logachev V. Mats A. Bardardinov E. Karabanov E. Baranova O. Khlystov V. Khrachenko M. Shimaraeva E. Kornakova S. Efremova E. Stolbova A. Gvozdkov V. Kravchinski T. Fileva S. Kashik T. Khramtsova I. Kalashnikova T. Rasskazova V. Tatarnikova R. Yuretich V. Mazilov K. Takemura V. Bobrov T. Gunicheva H. Haraguchi S. Ito T. Kocho M. Kuzmin M. Markova V. Pampura O. Proidakova H. Sawatari A. Takeuchi K. Toyoda S. Vorobieva A. Ikeda A. Marui T. Nakamura K. Ogura T. Ohta J. King J. Peck H. Sakai T. Yokoyama A. Hayashida E. Bezrukova S. Fowell N. Fuji P. Letunova V. Misharina N. Miyoshi G. Chernyaeva I. Ignatova E. Likhoshvai E. Stoermer L. Granina O. Levina P. Dolgikh R. Ishiwatari F. Lazo N. Lutskaia W. Orem E. Wada D. Williams K. Yamada S. Yamada E. Callander L. Golobokoval P. Shanks R. Dorofeeva A. Duchkov article https://doi.org/10.1029/97EO00358 From January to March 1996, an ice-based drilling platform (Figure 1) was positioned in 321 m of water above a submerged topographic high known as the Academician Ridge of Lake Baikal, south-central Siberia (Figure 2). The Russian Nedra drilling team expertly used this system to recover the first sediment cores from this region to span the last 5 m.y. before present (Ma). This operation was complicated and dangerous: there were constantly shifting blocks of ice nearly 1 m thick, the location was surrounded by wilderness areas nearly 400 km from the nearest population center (Irkutsk), and supplies and personnel had to travel 90 km over the ice pressure ridges in 4-wheel motorcycles and small vehicles. 1997 https://doi.org/10.1029/97EO00358 Eos, Transactions American Geophysical Union 78 597-601 51 https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/97EO00358 Baikal Drilling Project BDP-96 (Leg II) Members article Paillet199611675 Temperature and formation resistivity logs obtained in borehole KP-1 of the Hawaii Scientific Drilling Project indicate that the adjacent formation is characterized by several zones of distinctly different average temperature and water salinity. A series of hydraulic analyses and water sampling programs were conducted to rule out the possibility of local hydraulic effects associated with the presence of the borehole in the generation of these apparent groundwater zones. Hydraulic tests and sampling with the borehole cased to a depth of 710 m and open below that depth indicate that the deep aquifer contains seawater at a temperature nearly identical to that of the open ocean at the same depth. Various analyses give estimates of aquifer transmissivity of about 10-3 m2/s in the vicinity of the borehole. Isolation of this deeper aquifer from the overlying groundwater zones was investigated by perforating the casing at six locations and then measuring the changes in water level in the borehole, in the salinity of the fluid column, in the temperature profile of the fluid column, and in the rate of flow in the fluid column induced by the perforations. These results positively confirm that the zones of distinctly different formation properties indicated on the temperature and resistivity logs are not caused by flow in or around casing. Flow and fluid column salinity induced by the perforations also confirm significant differences between the hydraulic heads and geochemistry of the different groundwater zones inferred from the well logs. 1996 English 21699313 Journal of Geophysical Research: Solid Earth 101 American Geophysical Union 11675-11682 U.S. Geological Survey, Denver, CO, United States; Hawaii Institute of Geophysics, University of Hawaii, Honolulu, HI, United States; U.S. Geological Survey, MS 403, Box 25046 Federal Center, Denver, CO 80225, United States; Hawaii Institute of Geophysics, University of Hawaii at Manoa, 2525 Correa Road, Honolulu, HI 96822, United States 5 aquifer; borehole logging; groundwater; hydrogeology; salinity; temperature, Hawaii; USA https://www.scopus.com/inward/record.uri?eid=2-s2.0-3643129607&partnerID=40&md5=c3335912c340a6c15ac2a55e8bfbdbf3 cited By 7 F.L. Paillet D.M. Thomas article Sharp199611607 Mauna Kea lava flows cored in the HilIo hole range in age from &lt;200 ka to about 400 ka based on 40Ar/39Ar incremental heating and K-Ar analyses of 16 groundmass samples and one coexisting plagioclase. The lavas, all subaerially deposited, include a lower section consisting only of tholeiitic basalts and an upper section of interbedded alkalic, transitional tholeiitic, and tholeiitic basalts. The lower section has yielded predominantly complex, discordant 40Ar/39Ar age spectra that result from mobility of 40Ar and perhaps K, the presence of excess 40Ar, and redistribution of 39Ar by recoil. Comparison of K-Ar ages with 40Ar/39Ar integrated ages indicates that some of these samples have also lost 39Ar. Nevertheless, two plateau ages of 391 ± 40 and 400 ± 26 ka from deep in the hole, combined with data from the upper section, show that the tholeiitic section accumulated at an average rate of about 7 to 8 m/kyr and has an mean recurrence interval of 0.5 kyr/flow unit. Samples from the upper section yield relatively precise 40Ar/39Ar plateau and isotope correlation ages of 326 ± 23, 241 ± 5, 232 ± 4, and 199 ± 9 ka for depths of -415.7 m to -299.2 m. Within their uncertainty, these ages define a linear relationship with depth, with an average accumulation rate of 0.9 m/kyr and an average recurrence interval of 4.8 kyr/flow unit. The top of the Mauna Kea sequence at -280 m must be older than the plateau age of 132 ± 32 ka, obtained for the basal Mauna Loa flow in the corehole. The upward decrease in lava accumulation rate is a consequence of the decreasing magma supply available to Mauna Kea as it rode the Pacific plate away from its magma source, the Hawaiian mantle plume. The age-depth relation in the core hole may be used to test and refine models that relate the growth of Mauna Kea to the thermal and compositional structure of the mantle plume. 1996 English 21699313 10.1029/95jb03702 Journal of Geophysical Research: Solid Earth 101 American Geophysical Union 11607-11616 Berkeley Geochronology Center, Berkeley, CA, United States; U.S. Geological Survey, Menlo Park, CA, United States; U.S. Geological Survey, MS 977, 345 Middlefield Road, Menlo Park, CA 94025, United States; Berkeley Geochronology Center, 2455 Ridge Road, Berkeley, CA 94720, United States 5 accumulation rate; alkali basalt; argon-40/argon-39 dating; lava flow; petrology; potassium/argon dating; recurrence interval; tholeiite, USA, Hawaii, Hawaii https://www.scopus.com/inward/record.uri?eid=2-s2.0-0029729311&doi=10.1029%2f95jb03702&partnerID=40&md5=fc04401fcd1ed6f0db4055c75ba04a76 cited By 88 W.D. Sharp B.D. Turrin P.R. Renne M.A. Lanphere article Lipman199611631 Accumulation rates for lava flows erupted from Mauna Loa, as sampled in the uppermost 280 m of the Hilo drill hole, vary widely for short time intervals (several thousand years), but overall are broadly similar to those documented elsewhere on this volcano since 100 ka. Thickness variations and accumulation rates for Mauna Loa lavas at the Hilo drill site have been strongly affected by local paleotopography, including funneling and ponding between Mauna Kea and Kilauea. In addition, gentle submerged slopes of Mauna Kea in Hilo Bay have permitted large shoreline displacements by Mauna Loa flows. Ages of eruptive intervals have been determined from published isotopic data and from eustatic sea level curves modified to include the isostatic subsidence of the island of Hawaii at 2.2-2.6 mm/yr. Prior to 10 ka, rates of Mauna Loa lava accumulation at the drill site varied from 0.6 to 4.3 mm/yr for dateable intervals, with an overall rate of 1.8 mm/yr. Major eruptive pulses at about 1.3 and 10 ka, each probably representing a single long-lived eruption based on lack of weathering between flow units, increase the overall accumulation rate to 2.4 mm/yr. The higher rate since 10 ka reflects construction of thick near-shoreline lava deltas as postglacial sea levels rose rapidly. Large lava deltas form only along coastal segments where initially subaerial slopes have been submerged by the combined effects of eustatic sea level rise, isostatic subsidence, or spreading of volcano flanks. Overall accumulation of 239 m of lava at the drill site since 100-120 ka closely balances submergence of the Hilo area, suggesting that processes of coastal lava deposition have been modulated by rise in sea level. The Hilo accumulation rate is slightly higher than average rates of 1-2 mm/yr determined elsewhere along the Mauna Loa coast, based on rates of shoreline coverage and dated sea cliff and fault scarp exposures. Low rates of coastal lava accumulation since 100 ka, near or below the rate of island-wide isostatic subsidence, indicate that Mauna Loa is no longer growing vigorously or even maintaining its size above sea level. 1996 English 21699313 10.1029/95jb03214 Journal of Geophysical Research: Solid Earth 101 American Geophysical Union 11631-11641 U.S. Geological Survey, Menlo Park, CA, United States; U.S. Geological Survey, MS 910, 345 Middlefield Road, Menlo Park, CA 94025, United States 5 accumulation rate; coastal environment; lava delta; temporal variation; volcanic eruption, USA, Hawaii, Hawaii https://www.scopus.com/inward/record.uri?eid=2-s2.0-0029769194&doi=10.1029%2f95jb03214&partnerID=40&md5=8f5f14574e15454d3c85516e32a8f1ed cited By 33 P.W. Lipman J.G. Moore article Stolper199611593 1996 English 21699313 Journal of Geophysical Research: Solid Earth 101 American Geophysical Union 11593-11598 Div. of Geol. and Planetary Sciences, California Institute of Technology, Pasadena; Center for Isotope Geochemistry, Department of Geology and Geophysics, University of California, Berkeley; Hawaii Inst. Geophys. Planetology, Sch. Ocean Earth Sci. and Technol., University of Hawaii, Honolulu; Center for Isotope Geochemistry, Department of Geology and Geophysics, University of California, Berkeley, CA 94720-4767, United States; Div. of Geol. and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, United States; Hawaii Inst. Geophys. Planetology, Sch. Ocean Earth Sci. and Technol., Univresity of Hawaii, Honolulu, HI 96822, United States B5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-14244259538&partnerID=40&md5=833430d18e66a9d94a340ffd32614410 cited By 44 E.M. Stolper D.J. DePaolo D.M. Thomas article Thomas199611683 A series of downhole and surface water samples were taken from the 1-km-deep KP-1 borehole located on the eastern flank of the island of Hawaii. Early samples from depths of more than 700 m showed salinities nearly equivalent to seawater but having anomalous cation concentrations that are attributed to ion exchange between formation fluids and residual drilling mud clays. Later deep samples found only minor variations from seawater cation chemistry that are consistent with low-temperature weathering of basalts; δ18O values are equivalent to seawater values and are consistent with this interpretation. Carbon 14 activities of dissolved inorganic carbonate indicate a water age ranging from 5890 to 7170 years B.P. and fluid transport rates of 1.8 to 2.2 m/yr. Fluid samples from perforations at 310 m in the borehole demonstrate that a freshwater aquifer is present at the Mauna Kea/Mauna Loa interface; borehole resistivity logs indicate that it is ∼200 m thick. Although it has not yet been possible to obtain samples of the freshwater zone without contamination from the deep saline fluids, the chloride concentrations of the low-salinity zone are estimated using a mixing enthalpy calculation to be less than 100 mg/L. Light stable isotope data indicate that the fresh water at 320 m is derived from recharge entering the island at an average elevation of 2000 m. Inferred 14C activities of the dissolved bicarbonate in the freshwater zone indicate an average calibrated age of 2200 years B.P. and an average fluid velocity of at least 14 m/yr. A regional water flow model is proposed that suggests that the fresh water found at the 320-m depth is derived from rainfall recharge from the middle elevations of Mauna Kea volcano. This rainfall is channeled beneath the Mauna Loa lavas by the thick soil layer separating the two volcanoes. A second shallow fresh-to-brackish water zone, derived from Mauna Loa recharge, is also inferred to exist below the carbonate formation that underlies the shallow basal lens. The results of our preliminary study of the groundwater system below the KP-1 drill site demonstrate that intervolcano and interflow aquicludes can have a substantial impact on water circulation and discharge from young island volcanoes. 1996 English 21699313 10.1029/95jb03845 Journal of Geophysical Research: Solid Earth 101 American Geophysical Union 11683-11694 Hawaii Inst. Geophys. Planetology, Sch. Ocean Earth Sci. and Technol., University of Hawaii at Manoa, Honolulu, HI, United States; U.S. Geological Survey, Denver, CO, United States; Lawrence Berkeley Laboratory, Berkeley, CA, United States; Lawrence Berkeley Laboratory, Bldg. 70A, MS 33663, 1 Cyclotron Rd., Berkeley, CA 94720, United States; U.S. Geological Survey, MS 403, Box 25046 Federal Center, Denver, CO 80225, United States; Hawaii Inst. Geophys. Planetology, SOEST, University of Hawaii, 2525 Correa Road, Honolulu, HI 96822-2219, United States 5 fluid flow; freshwater; geochemistry; groundwater; hydrogeology; salinity, USA, Hawaii, Hawaii https://www.scopus.com/inward/record.uri?eid=2-s2.0-0029751779&doi=10.1029%2f95jb03845&partnerID=40&md5=fe8f677d942497ac0aabc8aafefe4016 cited By 29 D.M. Thomas F.L. Paillet M.E. Conrad article DePaolo1996 Petrological, geochemical, geomagnetic, and volcanological characterization of the recovered core from a 1056-m-deep well into the flank of the Mauna Kea volcano in Hilo, Hawaii, and downhole logging and fluid sampling have provided a unique view of the evolution and internal structure of a major oceanic volcano unavailable from surface exposures. Core recovery was ∼90%, yielding a time series of fresh, subaerial lavas extending back to ∼400 ka. Results of this 1993 project provide a basis for a more ambitious project to core drill a well 4.5 km deep in a nearby location with the goal of recovering an extended, high-density stratigraphic sequence of lavas. 1996 English 10525173 GSA Today 6 Geological Society of America x1-8 UC Berkeley; Caltech; U. Hawaii; JPL; USGS - HVO; MIT; Mainz, Germany; Lawrence Berkeley Lab; WHOI; USGS; BGC-Berkeley; U. Mass. 8 geochemistry; geomagnetic field; hotspot; petrology; volcanism; volcano, USA, Hawaii, Hawaii, Mauna Kea https://www.scopus.com/inward/record.uri?eid=2-s2.0-0030427741&partnerID=40&md5=6fd129cbc07efd46c462412571f44969 cited By 14 D. DePaolo E. Stolper D. Thomas F. Albarède O. Chadwick D. Clague M. Feigenson F. Frey M. Garcia A. Hofmann B.L. Ingram B.M. Kennedy J. Kirschvink M. Kurz C. Laj J. Lockwood K. Ludwig T. McEvilly R. Moberly G. Moore J. Moore R. Morin F. Paillet P. Renne M. Rhodes M. Tatsumoto H. Taylor G. Walker R. Wilkins article Rhodes199611729 Geochemical discriminants are used to place the boundary between Mauna Loa flows and underlying Mauna Kea flows at a depth of about 280 m. At a given MgO content the Mauna Kea flows are lower in SiO2 and total iron and higher in total alkali, TiO2, and incompatible elements than the Mauna Loa lavas. The uppermost Mauna Kea lavas (280 to 340 m) contain alkali basalts interlayered with tholeiites and correlate with the postshield Hamakua Volcanics. In addition to total alkalis, the alkali basalts have higher TiO2, P2O5, Sr, Ba, Ce, La, Zr, Nb, Y, and V relative to the tholeiites and lower Zr/Nb and Sr/Nb ratios. Some of the alkali basalts are extensively differentiated. Below 340 m all the flows are tholeiitic, with compositions broadly similar to the few "fresh" subaerial shield-building Mauna Kea tholeiites studied to date. High-MgO lavas are unusually abundant, although there is a wide range (7-28%) in MgO content reflecting olivine control. FeO/MgO relationships are used to infer parental picritic magmas with about 15 wt % MgO. Lavas with more MgO than this have accumulated olivine. The Mauna Loa lavas have compositional trends that are controlled by olivine crystallization and accumulation. They compare closely with trends for historical (1843-1984) flows, tending toward the depleted end of the spectrum. They are, though, much more MgO-rich (9-30%) than is typical for most historical and young (&lt;30 ka) prehistoric lavas. The unusual abundance of high-MgO and picritic lavas is attributed to the likelihood that only large-volume, hot, mobile flows will reach Hilo Bay from the northeast rift zone. FeO/MgO relationships are used to infer parental picritic magmas with about 17 wt % MgO. Again, lavas with more MgO than this have accumulated olivine. Systematic changes in incompatible element ratios are used to argue that the magma supply rate has diminished over time. On the other hand, the relatively constant Zr/Nb and Sr/Nb ratios that compare closely with historical and young (&lt;30 kyr) prehistoric flows are used to argue that the source components for these lavas in the Hawaiian plume have remained relatively uniform over the last 100 kyr. 1996 English 21699313 10.1029/95jb03704 Journal of Geophysical Research: Solid Earth 101 American Geophysical Union 11729-11746 Department of Geosciences, University of Massachusetts, Amherst, MA, United States; Department of Geosciences, University of Massachusetts, Morrill Science Center, Amherst, MA 01003, United States 5 basalt; geochemistry; lava flow; petrogenesis; stratigraphy, USA, Hawaii, Hawaii https://www.scopus.com/inward/record.uri?eid=2-s2.0-0029730270&doi=10.1029%2f95jb03704&partnerID=40&md5=aed7f67eed4cf1834097e60129222eb3 cited By 141 J.M. Rhodes article Yang199611747 The lower 776 m of core recovered during the initial phase of the Hawaii Scientific Drilling Project (HSDP) contains lavas erupted from Mauna Kea volcano. Tholeiitic and alkalic basalts, including an Fe-Ti rich flow, are intercalated in the upper 58 m of Mauna Kea lavas. Similar basaltic sections are subaerially exposed on the lower east flank of Mauna Kea. The Fe-Ti rich lavas reflect large amounts of clinopyroxene, plagioclase, and olivine fractionation within the crust and upper mantle, but the range from tholeiitic to alkalic compositions reflects variable extents of melting of a garnet-bearing source. Based on abundances of incompatible elements, the extent of melting for a basanitoid was a factor of 2 less than that for nearly coeval tholeiitic lavas. All flow units in the lower 718 m of the HSDP core are tholeiitic lavas. Their variability in major element compositions reflect variable accumulation of olivine. Incompatible element abundance ratios in these lavas reflect a complex temporal variation in extent of melting. Within the tholeiitic part of the core, lavas from 800 m to 950 m formed by the largest extent of melting, whereas tholeiitic lavas from the bottom of the core and from just below the tholeiitic to alkalic transition formed by lower degrees of melting. Inferred melt compositions at 16% MgO show that the ∼200 to 400 ka Mauna Kea lavas from the HSDP core and the &lt;250 ka subaerial exposures define an inverse correlation between SiO2 and FeO contents. Based on experimental studies, this correlation is caused by differing pressures of melt segregation. Furthermore, abundances of Nb and SiO2 are also inversely correlated in these calculated melts. In general, the younger lavas are relatively enriched in FeO and incompatible elements but are depleted in SiO2. These trends are interpreted to reflect an overall trend of increasing pressure of melt segregation and decreasing extent of melting with decreasing eruption age. There are, however, geochemical variations which indicate short-term reversals in this long-term trend. Previously, the geochemical trends accompanying the transition from tholeiitic to alkalic volcanism at Hawaiian volcanoes have been interpreted as reflecting the effects of increasing distance from the plume axis. The long-term geochemical trends of tholeiitic lavas in the HSDP core also reflect migration of Mauna Kea away from the Hawaiian plume. 1996 English 21699313 10.1029/95jb03465 Journal of Geophysical Research: Solid Earth 101 American Geophysical Union 11747-11767 Dept. Earth, Atmosph. Planet. Sci., Massachusetts Inst. of Technology, Cambridge, MA, United States; Department of Geology and Geography, University of Massachusetts, Amherst, MA, United States; Department of Geology and Geophysics, University of Hawaii at Manoa, Honolulu, HI, United States; Dept. Earth, Atmosph. Planet. Sci., Massachusetts Inst. of Technology, Cambridge, MA 02139-4307, United States; Department of Geology and Geophysics, SOEST, University of Hawaii at Manoa, 2525 Correa Road, Honolulu, HI 96822, United States; Department of Geology and Geography, University of Massachusetts, Morrill Science Center, Amherst, MA 01003-5820, United States 5 basalt; geochemistry; lava flow; petrogenesis; petrology; temporal evolution; volcano, USA, Hawaii, Hawaii, Mauna Kea https://www.scopus.com/inward/record.uri?eid=2-s2.0-0029749664&doi=10.1029%2f95jb03465&partnerID=40&md5=0c856606292a3cb7d5d9d4d719a64eca cited By 50 H.-J. Yang F.A. Frey J.M. Rhodes M.O. Garcia article Moore199611599 A 25.8-m-thick sedimentary section containing coral fragments occurs directly below a surface lava flow (the ∼1340 year old Panaewa lava flow) at the Hilo drill hole. Ten coral samples from this section dated by accelerator mass spectrometry (AMS) radiocarbon and five by thermal infrared multispectral scanner (TIMS) 230Th/U methods show good agreement. The calcareous unit is 9790 years old at the bottom and 1690 years old at the top and was deposited in a shallow lagoon behind an actively growing reef. This sedimentary unit is underlain by a 34-m-thick lava flow which in turn overlies a thin volcaniclastic silt with coral fragments that yield a single 14C date of 10,340 years. The age-depth relations of the dated samples can be compared with proposed eustatic sea level curves after allowance for island subsidence is taken. Island subsidence averages 2.2 mm/yr for the last 47 years based on measurements from a tide gage near the drill hole or 2.5-2.6 mm/yr for the last 500,000 years based on the ages and depths of a series of drowned coral reefs offshore from west Hawaii. The age-depth measurements of coral fragments are more consistent with eustatic sea levels as determined by coral dating at Barbados and Albrolhos Islands than those based on oxygen isotopic data from deep sea cores. The Panaewa lava flow entered a lagoon underlain by coral debris and covered the drill site with 30.9 m of lava of which 11 m was above sea level. This surface has now subsided to 4.2 m above sea level, but it demonstrates how a modern lava flow entering Hilo Bay would not only change the coastline but could extensively modify the offshore shelf. 1996 English 21699313 10.1029/95jb03215 Journal of Geophysical Research: Solid Earth 101 American Geophysical Union 11599-11605 U.S. Geological Survey, Menlo Park, CA, United States; Department of Geology and Geophysics, University of California, Berkeley, CA, United States; U.S. Geological Survey, Denver, CO, United States; U.S. Geological Survey, Hawaiian Volcano Observatory, Hawaii National Park, HI, United States; U.S. Geological Survey, Hawaiian Volcano Observatory, Hawaii National Park, HI 96718, United States; Department of Geology and Geophysics, University of California, Berkeley, CA 94720, United States; U.S. Geological Survey, Federal Center, Denver, CO 80225, United States; U.S. Geological Survey, MS 910, 345 Middlefield Road, Menlo Park, CA 94025, United States 5 age determination; coral; lava flow; radiocarbon dating; subsidence; thorium/uranium dating, USA, Hawaii, Hawaii https://www.scopus.com/inward/record.uri?eid=2-s2.0-0029751838&doi=10.1029%2f95jb03215&partnerID=40&md5=f065689c6758da3994586cede3b2150b cited By 43 J.G. Moore B.L. Ingram K.R. Ludwig D.A. Clague article Morin199611695 As part of the Hawaii Scientific Drilling Project, Kahi Puka Well 1 penetrated about 275 m of Mauna Loa basalts overlying a sequence of Mauna Kea flow units as it was drilled and cored to a total depth of 1053 m below land surface. A borehole televiewer (BHTV) was run in most of the well in successive stages prior to casing in order to obtain magnetically oriented acoustic images of the borehole wall. A total of 283 individual fractures were identified from this log and characterized in terms of strike and dip. These data are divided into three vertical sections based upon age and volcanic source, and lower hemisphere stereographic plots identify two predominant, subparallel fracture subsets common to each section. Assuming that most of the steeply dipping fractures observed in the BHTV log are tensile features generated within basalt flows during deposition and cooling, this fracture information can be combined with models of the evolution of the island of Hawaii to investigate the depositional history of these Mauna Loa and Mauna Kea basalts over the past 400 kyr. The directions of high-angle fractures appear to be generally parallel to topography or to the coastline at the time of deposition, as is supported by surface mapping of modern flows. Consequently, an overall counterclockwise rotation of about 75° in the strike of these fractures from the bottom to the top of the well represents a systematic change in depositional slope direction over time. We attribute the observed rotation in the orientations of the two predominant fracture subsets over the past 400 kyr to changes in the configurations of volcanic sources during shield building and to the structural interference of adjacent volcanoes that produces shifts in topographic patterns. 1996 English 21699313 10.1029/95jb03848 Journal of Geophysical Research: Solid Earth 101 American Geophysical Union 11695-11699 U.S. Geological Survey, Denver, CO, United States; U.S. Geological Survey, MS 403, Denver Federal Center, P.O. Box 25046, Denver, CO 80225, United States 5 borehole logging; borehole televiewer; fracture geometry; tensile fracture; volcano growth, USA, Hawaii, Hawaii https://www.scopus.com/inward/record.uri?eid=2-s2.0-0029776993&doi=10.1029%2f95jb03848&partnerID=40&md5=b397f583aa27f36d3bc72a9471710ca3 cited By 3 R.H. Morin F.L. Paillet article Peck199611365 We have conducted a paleomagnetic study of sediment cores obtained from the Selenga prodelta region of Lake Baikal, Russia. This record, which spans approximately the last 84 kyr, contributes to a better understanding of the nature of geomagnetic field behavior in Siberia and is a useful correlation and dating tool. We demonstrate that the Lake Baikal sediments are recording variations in the geomagnetic field. The directional record displays secular variation behavior with a geomagnetic excursion at 20 ka and additional excursions appearing as large-amplitude secular variation at 41, 61, and 67 ka. Smoothing of the geomagnetic excursion behavior occurs in Lake Baikal sediments owing to the intermediate sedimentation rate (13 cm kyr-1). The Lake Baikal relative paleointensity record correlates to absolute paleointensity data for the last 10 kyr and to relative paleointensity records from the Mediterranean Sea and Indian Ocean for the last 84 kyr. This correlation suggests a strong global (i.e., dipole) component to these records and further supports the reliability of sediments as recorders of relative geomagnetic paleointensity. We show that a relative geomagnetic intensity stratigraphy has a potential resolution of 7 kyr by correlating continental and marine records. The geomagnetic intensity stratigraphy helps constrain the age of the difficult to date Lake Baikal sediments. Article 1996 English 21699313 10.1029/96jb00328 Journal of Geophysical Research: Solid Earth 101 American Geophysical Union 11365 – 11385 5 Russian Federation, Lake Baikal; geomagnetic field; palaeointensity; palaeomagnetism; Quaternary; secular variation https://www.scopus.com/inward/record.uri?eid=2-s2.0-0029749674&doi=10.1029%2f96jb00328&partnerID=40&md5=32a120ebec8d782d0135b11fe3b4ddba Cited by: 105 J.A. Peck J.W. King S.M. Colman V.A. Kravchinsky article Colman1995769 CHANGES in insolation caused by periodic changes in the Earth's orbital parameters provide the primary forcing for global ice ages1–6. But it is not clear to what extent the climates in continental interiors are controlled directly by regional variations in insolation and to what extent they are driven instead by the highly nonlinear response of the oceans and ice sheets. Here we investigate this question using the record of biogenic silica in Lake Baikal as a proxy for climate change in this high-latitude mid-continental region. We find a good correlation between this record and that of marine oxygen isotopes4. Over the past 250 kyr the Baikal record exhibits both a strongly nonlinear component (manifested in a 100-kyr periodicity) and weaker direct-insolation components (manifested in the 41-kyr (obliquity) and 23- and 19-kyr (precession) orbital cycles). These results show that even though extreme continental climates such as this are influenced directly by insolation variations, they are dominated by the nonlinear rhythm of the oceans and ice sheets. © 1995 Nature Publishing Group. Article 1995 English 00280836 10.1038/378769a0 Nature 378 769 – 771 6559 Russian Federation, Lake Baikal; silicon dioxide; biogenic silica; climate response; continental climate; ice sheet dynamics; ocean dynamics; orbital forcing; climate; climate change; custody; dynamics; heat stroke; lake; orbit; rhythm; Russian Federation; sea https://www.scopus.com/inward/record.uri?eid=2-s2.0-0029515401&doi=10.1038%2f378769a0&partnerID=40&md5=20d4993cd7fd15419ea49568928dcccf Cited by: 241 S.M. Colman J.A. Peck E.B. Karabanov S.J. Carter J.P. Bradbury J.W. King D.F. Williams article Hacker1995743 Metamorphic coesite and diamond in the Dabie Shan, eastern China, testify to subduction of continental crust to >100 km depth. Exhumation of these ultrahigh-pressure rocks through the crust encompassed two stages. 1) South-dipping foliation, southeast-plunging stretching lineation, lineation-parallel isoclinal folds, and boudins indicate extreme subhorizontal shortening and subvertical extension during top-to-northwest shearing at 200-180 Ma. 2) Northwest-southeast sub-horizontal extension from 133 to 122 Ma was concentrated within an asymmetric structural dome in a magmatic complex that forms the northern half of the Dabie Shan. The preferred exhumation model involves two stages: Triassic identation - vertical extrusion and erosion - followed by Cretaceous plate margin transtension. -from Authors Article 1995 English 00917613 10.1130/0091-7613(1995)023<0743:WBTUEO>2.3.CO;2 Geology 23 743 – 746 8 China; Dabie Mountains; Geology; Continental crusts; Eastern China; Identation; Magmatic complexes; Stretching lineations; Transtension; Triassic; Ultrahigh pressure rocks; Cretaceous; exhumation; tectonics; transtension; Triassic; ultra high pressure metamorphism; Silica https://www.scopus.com/inward/record.uri?eid=2-s2.0-84879879070&doi=10.1130%2f0091-7613%281995%29023%3c0743%3aWBTUEO%3e2.3.CO%3b2&partnerID=40&md5=f82cf725168e743afbb7c1c8726783ea Cited by: 225 B.R. Hacker L. Ratschbacher L. Webb Dong Shuwen article Peck1994221 Rock-magnetic measurements of sediment cores from the Academician Ridge region of Lake Baikal, Siberia show variations related to Late Quaternary climate change. Based upon the well-dated last glacial-interglacial transition, variations in magnetic concentration and mineralogy are related to glacial-interglacial cycles using a conceptual model. Interglacial intervals are characterized by low magnetic concentrations and a composition that is dominated by low coercivity minerals. Glacial intervals are characterized by high magnetic concentrations and increased amounts of high coercivity minerals. The variation in magnetic concentration is consistent with dilution by diatom opal during the more productive interglacial periods. We also infer an increased contribution of eolian sediment during the colder, windier, and more arid glacial conditions when extensive loess deposits were formed throughout Europe and Asia. Eolian transport is inferred to deliver increased amounts of high coercivity minerals as staining on eolian grains during the glacial intervals. Variations in magnetic concentration and mineralogy of Lake Baikal sediment correlate to the SPECMAP marine oxygen-isotope record. The high degree of correlation between Baikal magnetic concentration/mineralogy and the SPECMAP oxygen-isotope record indicates that Lake Baikal sediment preserves a history of climate change in central Asia for the last 250 ka. This correlation provides a method of estimating the age of sediment beyond the range of the radiocarbon method. Future work must include providing better age control and additional climate proxy data, thereby strengthening the correlation of continental and marine climate records. © 1994. Article 1994 English 0012821X 10.1016/0012-821X(94)90062-0 Earth and Planetary Science Letters 122 221 – 238 1-2 Russian Federation, Lake Baikal; Russian Federation, Siberia, Lake Baikal; aeolian transport; climate change; marine oxygen isotope record; oxygen isotope; Quaternary; rock magnetic record https://www.scopus.com/inward/record.uri?eid=2-s2.0-0028192190&doi=10.1016%2f0012-821X%2894%2990062-0&partnerID=40&md5=c01c59b4ce68615b063251c79dae314d Cited by: 150 J.A. Peck J.W. King S.M. Colman V.A. Kravchinsky article 2395 1993 Russian Geology and Geophysics 34 55-63 id: 191 S. M. Colman V. M. Kuptsov G. A. Jones S. J. Carter article 1992457 Lake Baikal, a Miocene‐age rift lake in southeastern Siberia, is an especially promising site for paleoclimate studies. Its high‐latitude location (52°–56°N) makes it particularly sensitive to changes in solar insolation due to long‐period variations in the Earth's orbital parameters. These variations are widely believed to be the main forcing functions of climate change in the Quaternary [Hays et al., 1976; Imbrie et al., 1984. The extreme continentality of the climate in southeastern Siberia makes Baikal an ideal location to study temporal changes in seasonality. Baikal is also one of the few high‐latitude lakes that has not been glaciated during the last 1–2 million years [Grosswald, 1980], although a record of glaciation in its drainage basin is preserved in the lake sediments. Finally, Lake Baikal is the largest (23,000 km3), the deepest (1640 m), and one of the oldest extant lake systems in the world. The sedimentary section in the Baikal depression is more than 7 km thick and probably spans more than 15 million years [Hutchinson et al., 1992]. Accordingly, Lake Baikal sediments represent one of the longest and most complete continental climate records available anywhere in the world. ©1992. American Geophysical Union. All Rights Reserved. Article 1992 English 00963941 10.1029/91EO00340 Eos, Transactions American Geophysical Union 73 457 – 462 43 Russian Federation, Lake Baikal; age determination; dating; palaeoclimate; Pleistocene/Holocene boundary; sediment core; seismic reflection profile https://www.scopus.com/inward/record.uri?eid=2-s2.0-0027098780&doi=10.1029%2f91EO00340&partnerID=40&md5=8ba9ffd4fb7a5a00abfab9a24ee63e02 Cited by: 27 article Finney1991351 A suite of piston cores recovered from Lake Malawi (9-14°S, 34-35°E), east Africa in 1986 has been analyzed for major and minor elements, organic C and N, calcium carbonate and diatoms. An internally consistent stratigraphy was constructed from calcium carbonate abundance and variations in the two most abundant diatom genera, Stephanodiscus and Melosira, with age control obtained primarily from 14C dating of the carbonate. Differences with time in Fe abundance in a transect of cores from different water depths have been interpreted to reflect changes in chemocline depth. The depth to the chemocline was on the order of 100 m shallower than present prior to 3500 yr B.P., indicating less seasonality. Carbonate production and preservation appears to be related to climatically induced changes in both salinity and chemical distributions in the water column. The carbonate, which precipitates from surface waters, is most abundant during the interval from about 10,000 to 6000 yr B.P. This micrite most likely represents periods of low lake level when salinity increased and carbonate precipitation was enhanced. Sedimentary evidence suggests that lake levels were 100-150 m lower than present during this period. This record is different from climatic trends in northern intertropical Africa, but appears to also be related to changes in insolation and monsoon circulation. This is the northernmost basin in Africa reported to exhibit a "southern hemisphere" response to the early Holocene northern hemisphere summer insolation maximum. The climatic hingeline north of Lake Malawi (∼ 9°S) implied by our results is significantly south of that indicated by general-circulation model simulations, however. The cores show evidence for periods of abrupt climate change during the interval of generally arid climate. © 1991. 1991 English 00310182 10.1016/0031-0182(91)90167-P Palaeogeography, Palaeoclimatology, Palaeoecology 85 351-366 Duke University Marine Laboratory, Beaufort, NC 28516, United States 3-4 carbonate precipitation; chemocline depth; climate; climate trend; diatom; Holocene; lake level; micrite; palaeoclimate; palaeoclimate record; salinity; sedimentation, Malawi, Lake Malawi https://www.scopus.com/inward/record.uri?eid=2-s2.0-0026305665&doi=10.1016%2f0031-0182%2891%2990167-P&partnerID=40&md5=a8608bf6105d6592ac38727ddd47bbfe cited By 76 B.P. Finney T.C. Johnson