Deep subsurface igneous rocks from the Deccan traps harbor H2 and CO2 utilizing chemolithoautotrophic bacteria - Saha, Plaban K; Sahu, Rajendra P; Sar, Pinaki; Kazy, Sufia K (Biologia, 2024)

Deep subsurface microbial life in impact-altered Late Paleozoic granitoid rocks from the Chicxulub impact crater - Quraish, Sohaib Naseer; Cockell, Charles; Wuchter, Cornelia; Kring, David; Grice, Kliti; Coolen, Marco J. L. (Geobiology, 2024)
In 2016, IODP-ICDP Expedition 364 recovered an 829-meter-long core within the peak ring of the Chicxulub impact crater (Yucat'an, 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.
Keywords: 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

Disentangling influences of climate variability and lake-system evolution on climate proxies derived from isoprenoid and branched glycerol dialkyl glycerol tetraethers (GDGTs): The 250 kyr Lake Chala record - Baxter, Allix J.; Peterse, Francien; Verschuren, Dirk; Maitituerdi, Aihemaiti; Waldmann, Nicolas; Sinninghe Damst'e, Jaap S. (Biogeosciences, 2024)
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.
Keywords: Arequipa [Peru]; Chala; Peru; biomarker; climate variation; crater lake; ether; glacial-interglacial cycle; lacustrine deposit; paleoclimate; proxy climate record; seismic reflection; stratification

Drilling the Bosumtwi impact crater in Ghana: Implications for impact research and paleoclimatology - Koeberl, Christian (Past Global Changes Magazine, 2024)

Early Cretaceous sedimentary records of the early-stage continental rifting in the Songliao Basin, NE China - Fu, Yu; Cheng, Rihui; Gao, Youfeng; Zhou, Yang; Xu, Zhongjie (Journal of Asian Earth Sciences, 2024)

Early Cretaceous spore-pollen assemblages from the Shahezi Formation in Well SK-2 and their paleoclimate significance; [松科 2 井早白垩世沙河子组孢粉组合及其古气候意义] - Zhang, Dejun; Zheng, Yuejuan; Zhang, Shuqin; Zhang, Jian; Huang, Xin; Chen, Shuwang; Sun, Lei (Geological Bulletin of China, 2024)

Early Jurassic extrinsic solar system dynamics versus intrinsic Earth processes: Toarcian sedimentation and benthic life in deep-sea contourite drift facies, Cardigan Bay Basin, UK - Pie'nkowski, Grzegorz; Uchman, Alfred; Ninard, Krzysztof; Page, Kevin N.; Hesselbo, Stephen P. (Progress in Earth and Planetary Science, 2024)
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.

Early warning signals of the termination of the African Humid Period(s) - Trauth, Martin H.; Asrat, Asfawossen; Fischer, Markus L.; Hopcroft, Peter O.; Foerster, Verena; Kaboth-Bahr, Stefanie; Kindermann, Karin; Lamb, Henry F.; Marwan, Norbert; Maslin, Mark A.; Schaebitz, Frank; Valdes, Paul J. (Nature Communications, 2024)

Sea Level Changes Affect Seismicity Rates in a Hydrothermal System Near Istanbul - Mart'inez-Garz'on, P.; Beroza, G. C.; Bocchini, G. M.; Bohnhoff, M. (GEOPHYSICAL RESEARCH LETTERS, 2023)
Keywords: seismicity catalog; sea level change; hydrothermal region; strain; strainmeter; solid Earth tides

Pore Connectivity of Deep Lacustrine Shale and its Effect on Gas-bearing Characteristics in the Songliao Basin: Implications from Continental Scientific Drilling - Han, Shuangbiao; Huang, Jie; Wang, Chengshan; Cui, Jiayi (Acta Geologica Sinica (English Edition), 2023)

Seasonality and lake water temperature inferred from the geochemistry and sclerochronology of quaternary freshwater bivalves from the Turkana Basin, Ethiopia and Kenya - Cohen, Andrew S.; Manobianco, Julia; Dettman, David L.; Black, Bryan A.; Beck, Catherine; Feibel, Craig S.; Joordens, Josephine C.; Van Bocxlaer, Bert; Vonhof, Hubert (Quaternary Science Reviews, 2023)

Reversed Holocene temperature –moisture relationship in the Horn of Africa - Baxter, A.J.; Verschuren, D.; Peterse, F.; Miralles, D.G.; Martin-Jones, C.M.; Maitituerdi, A.; Meeren, T.; Van Daele, M.; Lane, C.S.; Haug, G.H.; Olago, D.O.; Sinninghe Damst'e, J.S. (Nature, 2023)

Response of diatom assemblages to orbital- and millennial-scale climatic variability since the penultimate glacial maximum in the northern limit of the Neotropics - Avendaño, D.; Caballero, M.; Ortega-Guerrero, B.; Lozano-Garc'ia, S. (Journal of Quaternary Science, 2023)
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.
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Reconstruction of Dead Sea lake level and mass balance back to 237 ka BP using halite fluid inclusions - Guillerm, E.; Gardien, V.; Waldmann, N.D.; Brall, N.S.; Ariztegui, D.; Schwab, M.J.; Neugebauer, I.; Lach, A.; Caupin, F. (Quaternary Science Reviews, 2023)
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
cited By 0
Keywords: 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

Re-investigations of the fossil fern Xiajiajienia mirabila (Dicksoniaceae) based on new material from the Lower Cretaceous of western Liaoning, China - Zhang, Li; Wang, Yongdong; Ruhl, Micha; Zhu, Yanbin; Li, Haijun (Cretaceous Research, 2023)

Radiolytically reworked Archean organic matter in a habitable deep ancient high-temperature brine - Nisson, Devan M.; Walters, Clifford C.; Chac'on-Patiño, Martha L.; Weisbrod, Chad R.; Kieft, Thomas L.; Sherwood Lollar, Barbara; Warr, Oliver; Castillo, Julio; Perl, Scott M.; Cason, Errol D.; Freifeld, Barry M.; Onstott, Tullis C. (Nature communications, 2023)
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.

Paleolakes of Eastern Africa: Zeolites, Clay Minerals, and Climate - McHenry, Lindsay J.; Foerster, Verena; Gebregiorgis, Daniel (Elements, 2023)
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.
Keywords: 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

Planning for the Lake Izabal Basin Research Endeavor (LIBRE) continental scientific drilling project in eastern Guatemala - Obrist-Farner, J.; Eckert, A.; Douglas, P. M. J.; P'erez, L.; Correa-Metrio, A.; Konecky, B. L.; Bauersachs, T.; Zimmerman, S.; Scheidt, S.; Brenner, M.; Kutterolf, S.; Maurer, J.; et al. (Scientific Drilling, 2023)

Pervasive carbonation of peridotite to listvenite (Semail Ophiolite, Sultanate of Oman): clues from iron partitioning and chemical zoning - Decrausaz, Thierry; Godard, Marguerite; Menzel, Manuel D.; Parat, Fleurice; Oliot, Emilien; Lafay, Romain; Barou, Fabrice (European Journal of Mineralogy, 2023)
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.
Keywords: 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

Palynological characteristics of plant communities in the eastern Arctic during the Early to Middle Calabrian Age - Lozhkin, Anatoly V.; Anderson, Patricia M. (Review of Palaeobotany and Palynology, 2023)
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.
Keywords: Anadyr; Arctic; Chukchi; Elgygytgyn Lake; Russian Federation; Calabrian; paleoclimate; palynology; plant community; Pleistocene; pollen; shrub; vegetation history

Paleolimnological responses of Ecuadorian p'aramo lakes to local and regional stressors over the last two millennia - Luethje, Melina; Benito, Xavier; Schneider, Tobias; Mosquera, Pablo V.; Baker, Paul; Fritz, Sherilyn C. (Journal of Paleolimnology, 2023)
Increasing surface air temperatures and human influences (e.g., agriculture, livestock grazing, tourism) are altering lacustrine ecosystems in the South American Andean p'aramo, 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 p'aramo 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.

Paleoenvironmental changes across the Mesozoic-Paleogene hyperthermal events - He, Tianchen; Kemp, David B.; Li, Juan; Ruhl, Micha (GLOBAL AND PLANETARY CHANGE, 2023)
Keywords: Mesozoic -Paleogene; Hyperthermal events; Climate change; Paleoenvironment

Paleo-Permeability Structure of the Crustal Section of the Samail Ophiolite Based on Automated Detection of Veins in X-Ray CT Core Images From the Oman Drilling Project - Akamatsu, Y.; Katayama, I.; Okazaki, K.; Michibayashi, K. (Geochemistry, Geophysics, Geosystems, 2023)

Significance of Secondary Fe-Oxide and Fe-Sulfide Minerals in Upper Peak Ring Suevite from the Chicxulub Impact Structure - Verhagen, Christina M.; Jung, Ji-In; Tikoo, Sonia M.; Wittmann, Axel; Kring, David A.; Brachfeld, Stefanie; Wu, Laying; Burns, Dale H.; Gulick, Sean P. S. (Minerals, 2023)

On the occurrence of rare nannoliths (calcareous nannofossils) in the Early Jurassic and their implications for the end-Triassic mass extinction - Paulsen, Maria; Thibault, Nicolas (Papers in Palaeontology, 2023)

Shallow- and deep-ocean Fe cycling and redox evolution across the Pliensbachian-Toarcian boundary and Toarcian Oceanic Anoxic Event in Panthalassa - Chen, Wenhan; Kemp, David B.; He, Tianchen; Newton, Robert J.; Xiong, Yijun; Jenkyns, Hugh C.; Izumi, Kentaro; Cho, Tenichi; Huang, Chunju; Poulton, Simon W. (EARTH AND PLANETARY SCIENCE LETTERS, 2023)

Two Small Volcanoes, One Inside the Other: Geophysical and Drilling Investigation of Bazina Maar in Western Eger Rift - Hrubcov'a, Pavla; Fischer, Tom'aš; Rapprich, Vladislav; Valenta, Jan; T'aboř'ik, Petr; Mrlina, Jan; Dahm, Torsten; Vylita, Tom'aš; Beranek, Roman; Klanica, Radek; Vlček, Josef; Turjakov'a, Veronika (EARTH AND SPACE SCIENCE, 2023)
Keywords: maar-diatreme volcano; magnetometry; electrical resistivity tomography; drilling; gravity survey; Eger Rift

Special Issue on Ophiolites and Oceanic Lithosphere - Kelemen, Peter B.; Matter, Jurg M.; Teagle, Damon A. H.; Coggon, Jude A.; Godard, Marguerite; Michibayashi, Katsuyoshi; Takazawa, Eiichi; Templeton, Alexis S.; Williams, Ken; Al Sulaimani, Zaher (JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH, 2023)

The Upper-Lower Cretaceous boundary in the southern Songliao Basin: A case study of ICDP borehole SK-3; [松辽盆地南部上、下白垩统界线研究:以松辽盆地 国际大陆科学钻探松科3井为例] - Gao, Hang; Wang, Pujun; Gao, Youfeng; Wan, Xiaoqiao; Yang, Guang; Hu, Jingsong; Wu, Huaichun (Earth Science Frontiers, 2023)
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.
Keywords: 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

Multiple S-isotopic evidence for seawater incursions during the deposition of the upper Cretaceous source rocks in the Songliao Basin, northeastern China - Xu, Yilun; Li, Dandan; Gao, Yuan; Li, Menghan; Sun, Lilin; Zhang, Xiaolin; Wang, Chengshan; Shen, Yanan (Chemical Geology, 2023)

Workshop report: PlioWest – drilling Pliocene lakes in western North America - Smith, A. J.; Ito, E.; Burls, N.; Clarke, L.; Donders, T.; Hatfield, R.; Kuehn, S.; Koutsodendris, A.; Lowenstein, T.; McGee, D.; Molnar, P.; Prokopenko, A.; et al. (Scientific Drilling, 2023)

Workshop on drilling the Nicaraguan lakes: bridging continents and oceans (NICA-BRIDGE) - Kutterolf, S.; Brenner, M.; Dull, R. A.; Freundt, A.; Kallmeyer, J.; Krastel, S.; Katsev, S.; Lebas, E.; Meyer, A.; P'erez, L.; Rausch, J.; Saballos, A.; et al. (Scientific Drilling, 2023)

Volcanosedimentary fill of the early Cretaceous Yingcheng formation and response to the end of continental rifting in the Songliao Basin: Constraints from well SK-2, northern Xujiaweizi fault depression - Wang, Ye; Cheng, Rihui; Shen, Yanjie; Fu, Yu; Xu, Zhongjie; Gao, Youfeng (MARINE AND PETROLEUM GEOLOGY, 2023)
Keywords: Yingcheng formation; Strike-slip faulting; Songliao basin; End of continental rifting; Early cretaceous; SK-2

Volcanic impact on terrestrial and aquatic ecosystems in the Eastern Mediterranean - Pickarski, Nadine; Kwiecien, Ola; Litt, Thomas (Communications Earth and Environment, 2023)

Unlocking national treasures: the core scanning approach - Damaschke, M.; Fellgett, M.W.; Howe, M.P.A.; Watson, C.J. (Geological Society Special Publication, 2023)

Underrepresentation of Local Researchers in Geophysical Studies at the Bosumtwi Impact Crater: Insights from A Systematic Review - Boateng, Cyril D.; Akurugu, Christopher A.; Wemegah, David D.; Danuor, Sylvester K. (Scientific African, 2023)

Timing and recurrence intervals for voluminous silicic eruptions from Amatitlan caldera (Guatemala) - Leon, A. Cisneros; Danisik, M.; Schindlbeck-Belo, J. C.; Kutterolf, S.; Schmitt, A. K.; Freundt, A.; Kling, J.; Wang, K. -L.; Lee, H. -Y. (QUATERNARY SCIENCE REVIEWS, 2023)
Keywords: Quaternary geochronology; Zircon; (UeTh)/He; SIMS; Central America; 40Ar/39Ar

The response of borehole water levels in an ophiolitic, peridotite aquifer to atmospheric, solid Earth, and ocean tides - Sohn, R.A.; Matter, J.M. (Journal of Hydrology X, 2023)

Study of Depression and Layer Controlled Geothermal System in Songliao Basin (in Chinese with English abstract);[松辽盆地坳陷层控地热系统研究] - Wang, G.; Ma, F.; Hou, H.; Jiang, G.; Zhang, X.; Yuan, R.; Li, C. (Acta Geoscientica Sinica, 2023)

The Possible Role of Anoxic Alkaline High Subcritical Water in the Formation of Ferric Minerals, Methane and Disordered Graphitic Carbon in a BARB3 Drilled Sample of the 3.4 Ga Buck Reef Chert - Bassez, Marie-Paule (Origins of Life and Evolution of Biospheres, 2023)

The origin of carbonates in impact melt-bearing breccias from Site M0077 at the Chicxulub impact structure, Mexico - Garroni, Nicolas D.; Osinski, Gordon R. (Meteoritics and Planetary Science, 2023)
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.

The geodynamic and limnological evolution of Balkan Lake Ohrid, possibly the oldest extant lake in Europe - Wagner, Bernd; Tauber, Paul; Francke, Alexander; Leicher, Niklas; Binnie, Steven A.; Cvetkoska, Aleksandra; Jovanovska, Elena; Just, Janna; Lacey, Jack H.; Levkov, Zlatko; Lindhorst, Katja; Kouli, Katerina; et al. (Boreas, 2023)
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.
Keywords: Balkan; Lake Ohrid; Turkmenistan; clast; displacement; geodynamics; lacustrine deposit; lake evolution; limnology; sedimentation; sedimentology

The effect of temperature on the nonlinear elasticity of a fault rock in dynamic acoustoelastic testing (DAET) experiments - Simpson, Jonathan; Malcolm, Alison E.; Wijk, Kasper (Geophysical Journal International, 2023)

The Chicxulub impact structure reveals the first in-situ Jurassic magmatic intrusions of the Yucat'an Peninsula, Mexico - Graaff, S.J.; Ross, C.H.; Feignon, J.-G.; Kaskes, P.; Gulick, S.P.S.; Goderis, S.; D'ehais, T.; Debaille, V.; Ferrière, L.; Koeberl, C.; Mattielli, N.; Stockli, D.F.; et al. (Lithos, 2023)
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 Yucat'an 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 Yucat'an 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 Yucat'an 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 Yucat'an 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.
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The Br'ecy depocenter as part of a new northern Massif Central Carboniferous –Permian Basin (France) - Beccaletto, Laurent; Bourquin, Sylvie (Comptes Rendus - Geoscience, 2023)

Terrestrial dominance of organic carbon in an Early Cretaceous syn-rift lake and its correlation with depositional sequences and paleoclimate - Wang, Qianyou; Li, Yaohua; Utley, James E.P.; Gardner, Joe; Liu, Bei; Hu, Jianfang; Shao, Longyi; Wang, Xin; Gao, Fenglin; Liu, Dadong; Li, Haibin; Jiang, Zhenxue; et al. (Sedimentary Geology, 2023)
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
Keywords: 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

Techanical properties and microscopic pore structure evolution mechanism of shale under deep well temperature and humidity environment (in Chinese with English abstract);[深井温湿环境下泥页岩力学特性及微观孔隙结构演化机制] - Sun, L.; Ling, X.; Guan, D.; Zhou, Q.; Fan, Z.; Liu, B. (Exploration Engineering, 2023)

Olivine–The Alteration Rock Star - Pl{umper, Oliver; Matter, Juerg (Elements, 2023)
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.
Keywords: 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

Parapatric speciation of Meiothermus in serpentinite-hosted aquifers in Oman - Munro-Ehrlich, Mason; Nothaft, Daniel B.; Fones, Elizabeth M.; Matter, Juerg M.; Templeton, Alexis S.; Boyd, Eric S. (FRONTIERS IN MICROBIOLOGY, 2023)
Keywords: subsurface; serpentinite; recombination; evolution; geographic isolation; parapatric speciation; dispersal limitation; competitive exclusion

Millennial hydrological variability in the continental northern Neotropics during Marine Isotope Stages (MISs) 3-2 (59-15 cal ka BP) inferred from sediments of Lake Pet'en Itz'a, Guatemala - Mart'inez-Abarca, Rodrigo; Abstein, Michelle; Schenk, Frederik; Hodell, David; Hoelzmann, Philipp; Brenner, Mark; Kutterolf, Steffen; Cohuo, Sergio; Macario-Gonz'alez, Laura; Stockhecke, Mona; Curtis, Jason; Anselmetti, Flavio S.; et al. (Climate of the Past, 2023)
Lake Pet'en Itz'a (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 Pet'en Itz'a 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 Pet'en Itz'a (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 Mart'inez-Abarca et al.
Keywords: 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

Climate-controlled sensitivity of lake sediments to record earthquake-related mass wasting in tropical Lake Towuti during the past 40 kyr - Tournier, Nicolas; Fabbri, Stefano C.; Anselmetti, Flavio S.; Cahyarini, Sri Yudawati; Bijaksana, Satria; Wattrus, Nigel; Russell, James M.; Vogel, Hendrik (Quaternary Science Reviews, 2023)
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
Keywords: 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

Drilling into a deep buried valley (ICDP DOVE): a 252 m long sediment succession from a glacial overdeepening in northwestern Switzerland - Schaller, S.; Buechi, M. W.; Schuster, B.; Anselmetti, F. S. (Scientific Drilling, 2023)

Development of the Chinese Continental Scientific Deep Drilling: Perspectives and Suggestions; [中国大陆科学深钻发展的若干思考与建议] - Zou, Changchun; Wang, Chengshan; Peng, Cheng; Wu, Caowei; Gao, Yuan (Geoscience, 2023)

Development of Songliao Basin by Palaeo-Pacific slab rollback: Evidence from Early Cretaceous rhyolites in SK2 Borehole, NE China - Zhang, Zhao; Huang, Feng; Xu, Jifeng; Liu, Xijun; Zhang, Liying; Zhang, Man; Yang, Xuli; Zeng, Yunchuan; Liu, Qian (Geological Journal, 2023)
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.
Keywords: China; Songliao Basin; borehole; Cretaceous; geodynamics; hafnium; isotopic composition; neodymium isotope; petrogenesis; rhyolite; strontium isotope; uranium-lead dating; volcanic rock

Deciphering the tectonometamorphic history of subducted metapelites using quartz-in-garnet and Ti-in-quartz (QuiG-TiQ) geothermobarometry–A key for understanding burial in the Scandinavian Caledonides - Jeanneret, Pauline; Klonowska, Iwona; Barnes, Christopher; Majka, Jarosław; Holmberg, Johanna; Gillio, Mattia; Nachlas, William; Alvaro, Matteo; Ko'smi'nska, Karolina; Lorenz, Henning; Zack, Thomas; Ladenberger, Anna; et al. (Journal of Metamorphic Geology, 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 J{amtland. 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.
_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1111/jmg.12693
Keywords: 40Ar/39Ar dating; Scandinavian Caledonides; P & ndash; T & ndash; D & ndash; t evolution; quartz-in-garnet; Ti-in-quartz thermobarometry

Cross-Property Relationship Between Electrical Resistivity and Elastic Wave Velocity of Crustal Rocks From the Oman Drilling Project Hole GT3A: Implications for in Situ Geophysical Properties of Oceanic Crust - Akamatsu, Y.; Nagase, K.; Abe, N.; Okazaki, K.; Hatakeyama, K.; Katayama, I. (JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH, 2023)
Keywords: electrical resistivity; elastic wave velocity; oceanic crust; crack; Oman drilling Project; IODP hole 1256D

Country-wide exploration for graphite- and sulphide-rich black shales with airborne geophysics and petrophysical and geochemical studies - Loukola-Ruskeeniemi, Kirsti; Hyv{onen, Eija; Airo, Meri-Liisa; Lerssi, Jouni; Arkimaa, Hilkka (Journal of Geochemical Exploration, 2023)
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)
Keywords: 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

Continental geological evidence for Solar System chaotic behavior in the Late Cretaceous - Wu, Huaichun; Hinnov, Linda A.; Zhang, Shihong; Jiang, Ganqing; Yang, Tianshui; Li, Haiyan; Xi, Dangpeng; Ma, Xiaojuan; Wang, Chengshan (Bulletin of the Geological Society of America, 2023)
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
Keywords: 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

Constraints on the Nd-isotopic composition and nature of the last major influx of magma into the Bushveld Complex - Magson, Justine; Roelofse, Frederick; Bybee, Grant; Bolhar, Robert (Contributions to Mineralogy and Petrology, 2023)

Boron geochemistry reveals the evolution of Dead Sea brines - Jurikova, Hana; Ring, Simon J.; Henehan, Michael J.; Neugebauer, Ina; Schr{oder, Birgit; M{uller, Daniela; Schwab, Markus J.; Tjallingii, Rik; Brauer, Achim; Blanchet, C'ecile (Earth and Planetary Science Letters, 2023)
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)
Keywords: 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

Eastward extension of the Solonker Suture beneath the central Songliao Basin, NE China: Evidence from a deep seismic reflection profile - Li, Ming-Rui; Gao, Rui; Zhou, Jian-Bo; Wilde, Simon A; Hou, He-Sheng; Deng, Xiao-Fan (Gondwana Research, 2023)

Bayesian seismic travel-time cross-hole tomography in vertically transversely isotropic media - Haberland, C.; Ryberg, T.; Riedel, M.; Bauer, K. (Journal of Applied Geophysics, 2023)
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
cited By 0
Keywords: 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

Authigenic minerals reflect microbial control on pore waters in a ferruginous analogue - Vuillemin, A.; Morlock, M.; Paskin, A.; Benning, L. G.; Henny, C.; Kallmeyer, J.; Russell, J. M.; Vogel, H. (GEOCHEMICAL PERSPECTIVES LETTERS, 2023)

Authigenic mineralization in Surtsey basaltic tuff deposits at 50 years after eruption - Montesano, Giovanna; Rispoli, Concetta; Petrosino, Paola; Jackson, Marie D.; Weisenberger, Tobias B.; Gudmundsson, Magnus T.; Cappelletti, Piergiulio (SCIENTIFIC REPORTS, 2023)

Application of improved support vector machine in geochemical lithology identification - Yin, Shitao; Lin, Xiaochun; Huang, Yongjian; Zhang, Zhifeng; Li, Xiang (Earth Science Informatics, 2023)
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.
Keywords: China; Songliao Basin; geochemical method; identification method; lithology; logging (geophysics); machine learning; support vector machine; weight

An astronomical time scale for the Early Cretaceous continental strata in the Songliao Basin, Northeastern China (in Chinese with English abstract); [松辽盆地松科2井早白垩世沙河子组天文年代标尺] - Ma, X.; Li, S.; Chu, R.; Fang, Q.; Shi, M.; Wu, H. (Quaternary Sciences, 2023)

A neotropical perspective on the uniqueness of the Holocene among interglacials - Schiferl, J.; Kingston, M.; Åkesson, C.M.; Valencia, B.G.; Rozas-Davila, A.; McGee, D.; Woods, A.; Chen, C.Y.; Hatfield, R.G.; Rodbell, D.T.; Abbott, M.B.; Bush, M.B. (Nature Communications, 2023)

3-D imaging of the Balmuccia peridotite body (Ivrea-Verbano zone, NW-Italy) using controlled source seismic data - Ryberg, Trond; Haberland, Christian; Wawerzinek, Britta; Stiller, Manfred; Bauer, Klaus; Zanetti, Alberto; Ziberna, Luca; Hetenyi, Gyoergy; M{untener, Othmar; Weber, Michael M.; Krawczyk, Charlotte M. (GEOPHYSICAL JOURNAL INTERNATIONAL, 2023)
Keywords: Europe; Controlled source seismology; Seismic tomography; Continental tectonics: compressional; Crustal structure

Milankovitch cycle identification of Denglouku Formation in Songliao Basin and its paleoclimate significance (in Chinese with English abstract); [松科3井下白垩统登娄库组米兰科维奇旋回识别及其古气候意义] - Luo, L.; Yu, M.; Li, Q.; Wu, Z.; Huang, Y. (Sedimentary Geology and Tethyan Geology, 2023)

Early Diagenesis in the Lacustrine Ostracods from the Songliao Basin 91.35 Million Years Ago and Its Geological Implications - Liu, Zhenwu; Liu, Yuke; Du, Xuejia; Lyu, Dan; Wu, Huaichun; Wang, Huajian (Minerals, 2023)

A one-million-year isotope record from siderites formed in modern ferruginous sediments - Vuillemin, Aurèle; Mayr, Christoph; Schuessler, Jan A.; Friese, Andr'e; Bauer, Kohen W.; L{ucke, Andreas; Heuer, Verena B.; Glombitza, Clemens; Henny, Cynthia; Blanckenburg, Friedhelm; Russell, James M.; Bijaksana, Satria; et al. (Bulletin of the Geological Society of America, 2023)
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
Keywords: 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

Effect of Pressure Perturbations on CO2 Degassing in a Mofette System: The Case of Hartoušov, Czech Republic - Woith, Heiko; Vlček, Josef; Vylita, Tom'aš; Dahm, Torsten; Fischer, Tom'aš; Daskalopoulou, Kyriaki; Zimmer, Martin; Niedermann, Samuel; Stammeier, Jessica A.; Turjakov'a, Veronika; Lanzend{orfer, Martin (Geosciences (Switzerland), 2023)
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.

In-situ physical and elastic properties of Archaean basement granitoids in the Koyna seismogenic zone, western India from 3 km downhole geophysical well logs: Implications for water percolation at depth - Podugu, Nagaraju; Goswami, Deepjyoti; Akkiraju, Vyasulu V.; Roy, Sukanta (TECTONOPHYSICS, 2023)
Keywords: Fault zone; Downhole geophysical logs; Recurrent earthquakes; Scientific drilling; Koyna; India

Enrichment of rare methanogenic Archaea shows their important ecological role in natural high-CO2 terrestrial subsurface environments - Jia, Zeyu; Lipus, Daniel; Burckhardt, Oliver; Bussert, Robert; Sondermann, Megan; Bartholom{aus, Alexander; Wagner, Dirk; Kallmeyer, Jens (Frontiers in Microbiology, 2023)

Magma is the Key to Sustainable Super-Hot Geothermal Energy - Eichelberger, John; Lavallee, Yan; Mortensen, Anette; Papale, Paolo; Sigmundsson, Freysteinn (Transactions - Geothermal Resources Council, 2023)

Joint passive seismic imaging based on surface wave inversion and reflection wavefield retrieval: A case study in the sedimentary basin areas adjacent to Well Songke-2 - Jin, Zhong-Yuan; Hou, He-Sheng; Fu, Wei; Zhang, Pan; An, Dong-Zhao; Hu, Yong (Journal of Applied Geophysics, 2023)
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.
Keywords: 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

Iron-mediated anaerobic ammonium oxidation recorded in the early Archean ferruginous ocean - Pellerin, Alice; Thomazo, Christophe; Ader, Magali; Marin-Carbonne, Johanna; Alleon, Julien; Vennin, Emmanuelle; Hofmann, Axel (GEOBIOLOGY, 2023)
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.
Keywords: ammonium oxidation; biogeochemistry; Buck Reef Chert; Feammox; ferruginous ocean; nitrogen isotopes; Paleoarchean

Insights into organic metagenesis using Raman spectroscopy and high resolution mass spectrometry: A case study of the Shahezi formation, deep Songliao basin, China - Han, Shuangbiao; Xie, Linfeng; Du, Xin; Xiang, Chaohan; Huang, Jie; Tang, Zhiyuan; Wang, Chengshan; Horsfield, Brian; Mahlstedt, Nicolaj (International Journal of Coal Geology, 2023)
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
Keywords: 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

Initial results of coring at Prees, Cheshire Basin, UK (ICDP JET project): towards an integrated stratigraphy, timescale, and Earth system understanding for the Early Jurassic - Hesselbo, S. P.; Al-Suwaidi, A.; Baker, S. J.; Ballabio, G.; Belcher, C. M.; Bond, A.; Boomer, I.; Bos, R.; Bjerrum, C. J.; Bogus, K.; Boyle, R.; Browning, J. V.; et al. (Scientific Drilling, 2023)

Incompatibility between serpentinization and epidote formation in the lower oceanic crust: Evidence from the Oman Drilling Project - Nozaka, Toshio; Tateishi, Yamato (JOURNAL OF METAMORPHIC GEOLOGY, 2023)
Keywords: epidote; lower oceanic crust; olivine gabbro; Oman ophiolite; prehnite; serpentinization

Machine-learning-based morphological analyses of leaf epidermal cells in modern and fossil ginkgo and their implications for palaeoclimate studies - Zhang, Li; Wang, Yongdong; Ruhl, Micha; Xu, Yuanyuan; Zhu, Yanbin; An, Pengcheng; Chen, Hongyu; Yan, Defei (PALAEONTOLOGY, 2023)
Keywords: Ginkgo; epidermal cell; micro-character; machine learning; palaeoclimate parameter

Implications of a short carbon pulse on biofilm formation on mica schist in microcosms with deep crystalline bedrock groundwater - Nuppunen-Puputti, Maija; Kiet{av{ainen, Riikka; Kukkonen, Ilmo; Bomberg, Malin (Frontiers in Microbiology, 2023)
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, Kiet{av{ainen, Kukkonen and Bomberg.
Keywords: 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

Experimental study on nonlinear mechanical behavior and sampling damage characteristics of rocks from depths of 4900 –6830 m in Well Songke-2; [松科二井4900 6830 m不同深度岩石非线性力学行为和取样损伤特性试验研究] - Yang, Ming-qing; Li, Jia-nan; Gao, Ming-zhong; Chen, Ling; Li, Cong; He, Zhi-qiang; Wei, Zi-jie; Xie, He-ping (Journal of Central South University, 2023)
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.
Keywords: 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

Environmental changes during the onset of the Late Pliensbachian Event (Early Jurassic) in the Cardigan Bay Basin, Wales - Hollaar, Teuntje P.; Hesselbo, Stephen P.; Deconinck, Jean-François; Damaschke, Magret; Ullmann, Clemens V.; Jiang, Mengjie; Belcher, Claire M. (Climate of the Past, 2023)
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.
Keywords: Cardigan Bay; United Kingdom; Wales; carbon cycle; chemical weathering; climate forcing; environmental change; orbital forcing; organic matter; paleoenvironment; palynology; Pliensbachian; thermohaline circulation

Hyperspectral core scanner: An effective mineral mapping tool for apatite in the Upper Zone, northern limb, Bushveld Complex - Mandende, H; Ndou, C; Mothupi, T (Journal of the Southern African Institute of Mining and Metallurgy, 2023)

Evaluating geophysical logs as proxies for cyclostratigraphy in lacustrine deposits using power ratio accumulation - Peng, Cheng; Zou, Changchun; Wu, Huaichun; Zhang, Shuxia; Kouamelan, Kouamelan Serge; Wang, Chengshan (Palaeogeography, Palaeoclimatology, Palaeoecology, 2023)

Magmatism during the continent - ocean transition - Rooney, Tyrone O.; Brown, Eric L.; Bastow, Ian D.; Arrowsmith, J. Ram'on; Campisano, Christopher J. (EARTH AND PLANETARY SCIENCE LETTERS, 2023)
Keywords: rifting; East Africa; Afar Stratoid Series; magmatism

Ground Surface Temperature History Since the Last Glacial Maximum in Northeast Asia: Reconstructions From the Borehole Geotherms of the International Continental Scientific Drilling Program - Jiang, Guangzheng; Tian, Yuntao; Lv, Qingtian; Sandiford, Mike; Shi, Yizuo; Zou, Changchun; Ma, Feng; Deng, Chenglong; He, Lijuan; Hu, Shengbiao (Geophysical Research Letters, 2023)

Hydrogeochemical and isotopic signatures elucidate deep subsurface hypersaline brine formation through radiolysis driven water-rock interaction - Nisson, D.M.; Kieft, T.L.; Drake, H.; Warr, O.; Sherwood Lollar, B.; Ogasawara, H.; Perl, S.M.; Friefeld, B.M.; Castillo, J.; Whitehouse, M.J.; Kooijman, E.; Onstott, T.C. (Geochimica et Cosmochimica Acta, 2023)
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.
Keywords: Groundwater; Brine; Radiolysis; Isotope geochemistry; Deep biosphere

Hierarchical Milankovitch and sub-Milankovitch cycles in the environmental magnetism of the lower Shahezi Formation, Lower Cretaceous, Songliao Basin, northeastern China - Zhang, Shujing; Wu, Huaichun; Zhang, Shihong; Yang, Tianshui; Li, Haiyan; Fang, Qiang; Shi, Meinan (Frontiers in Earth Science, 2023)
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.
Keywords: China; Songliao Basin; Cretaceous; cyclostratigraphy; geomagnetism; hierarchical system; lacustrine deposit; Milankovitch cycle; paleoclimate; paleoenvironment

Holocene variations in Lake Titicaca water level and their implications for sociopolitical developments in the central Andes - Gu'edron, St'ephane; Delaere, Christophe; Fritz, Sherilyn C.; Tolu, Julie; Sabatier, Pierre; Devel, Anne-Lise; Heredia, Carlos; V'erin, Claire; Alves, Eduardo Q.; Baker, Paul A. (Proceedings of the National Academy of Sciences of the United States of America, 2023)
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).
Keywords: 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

Multisegment ruptures and Vp/Vs variations during the 2020-2021 seismic crisis in western Corinth Gulf, Greece - Mesimeri, Maria; Ganas, Athanassios; Pankow, Kristine L (Geophysical Journal International, 2022)
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.
Keywords: 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

Near-surface three-dimensional multicomponent source and receiver S-wave survey in the Tannwald Basin, Germany: Acquisition and data processing - Burschil, Thomas; Buness, Hermann; Schmelzbach, Cedric (Near Surface Geophysics, 2022)

NEW APPROACH TO SEPARATE AND DATE SMALL SPORES AND POLLEN FROM LAKE SEDIMENTS IN SEMI-ARID CLIMATES - Steinhoff, Christoph; Pickarski, Nadine; Litt, Thomas; Hajdas, Irka; Welte, Caroline; Wurst, Peter; K{uhne, David; Dolf, Andreas; Germer, Maximilian; Kallmeyer, Jens (Radiocarbon, 2022)

New insights into the formation and emplacement of impact melt rocks within the Chicxulub impact structure, following the 2016 IODP-ICDP Expedition 364 - Graaff, S.J.; Kaskes, P.; D'ehais, T.; Goderis, S.; Debaille, V.; Ross, C.H.; Gulick, S.P.S.; Feignon, J.-G.; Ferrière, L.; Koeberl, C.; Smit, J.; Mattielli, N.; et al. (Bulletin of the Geological Society of America, 2022)
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 (Yucat'an, 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.
cited By 10

New Rock Magnetic Analysis of Ultramafic Cores From the Oman Drilling Project and Its Implications for Alteration of Lower Crust and Upper Mantle - Hong, Gilbert; Till, Jessica Lynn; Greve, Annika; Lee, Sang-Mook; Party, Oman Drilling Project Phase 2 Science (Journal of Geophysical Research: Solid Earth, 2022)

No evidence of multiple impact scenario across the Cretaceous/Paleogene boundary based on planktic foraminiferal biochronology - ARZ, Jos'e A.; Arenillas, I.; Grajales-Nishimura, J.M.; Liesa, C.L.; Soria, A.R.; Rojas, R.; Calmus, T.; Gilabert, V. (Special Paper of the Geological Society of America, 2022)

Numerical Simulation of Coastal Sub-Permafrost Gas Hydrate Formation in the Mackenzie Delta, Canadian Arctic - Li, Z.; Spangenberg, E.; Schicks, J.M.; Kempka, T. (Energies, 2022)
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.
cited By 1
Keywords: 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

Oil and gas basin analysis based on airborne gravity and magnetic data - Liu, Y.-X.; Li, W.-Y.; Ma, G.-Q.; Cao, A.-Q.; Gao, S.; Wang, N.; Lu, W.-F.; Wang, L.-J.; Yang, C. (Applied Geophysics, 2022)
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.
cited By 2

Obliquity-forced aquifer-eustasy during the Late Cretaceous greenhouse world - Zhang, Zhifeng; Huang, Yongjian; Li, Mingsong; Li, Xiang; Ju, Pengcheng; Wang, Chengshan (Earth and Planetary Science Letters, 2022)
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.
Keywords: 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

Phases of stability during major hydroclimate change ending the Last Glacial in the Levant - M{uller, Daniela; Neugebauer, Ina; Ben Dor, Yoav; Enzel, Yehouda; Schwab, Markus J.; Tjallingii, Rik; Brauer, Achim (Scientific Reports, 2022)

Ongoing alteration of mantle peridotite in the weathering horizon: Initial results from the Oman Drilling Project Multi-Borehole Observatory - Kelemen, Peter B; Leong, James A; Obeso, Juan Carlos; Matter, Juerg; Ellison, Eric T; Templeton, Alexis S; Nothaft, Daniel B; Eslami, Alireza; Evans, Katy; Godard, Marguerite; et al. (Authorea Preprints, 2022)

Orbital control of Pleistocene euxinia in Lake Magadi, Kenya - Deocampo, D.M.; Owen, R.B.; Lowenstein, T.K.; Renaut, R.W.; Rabideaux, N.M.; Billingsley, A.; Cohen, A.; Deino, A.L.; Sier, M.J.; Luo, S.; Shen, C.-C.; Gebregiorgis, D.; et al. (Geology, 2022)

Orbitally forced chemical weathering in the Late Cretaceous northeastern China: Implications for paleoclimate change - Li, Xiang; Huang, Yongjian; Zhang, Zhifeng; Wang, Chengshan; Yang, Tianshui (Global and Planetary Change, 2022)
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.
Keywords: 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

Petrographic and geochemical characteristics of the granitic basement rocks below Deccan Traps obtained from scientific drilling to 3014 m depth in the Koyna region, western India - Shukla, Matsyendra Kumar; Vishnu, C.S.; Roy, Sukanta (Journal of Earth System Science, 2022)

Petrophysics of Chicxulub Impact Crater's Peak Ring - Le Ber, E.; Loggia, D.; Denchik, N.; Lofi, J.; Kring, D.A.; Sardini, P.; Siitari-Kauppi, M.; Pezard, P.; Olivier, G.; Party, IODP-ICDP Expedition 364 Science (Journal of Geophysical Research: Solid Earth, 2022)
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 < m < 1.87) and the formation factor (21 < F < 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.
cited By 0

Molecular hydrogen from organic sources in the deep Songliao Basin, P.R. China - Horsfield, B.; Mahlstedt, N.; Weniger, P.; Misch, D.; Vranjes-Wessely, S.; Han, S.; Wang, C. (International Journal of Hydrogen Energy, 2022)
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
cited By 5
Keywords: 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

Orbital controls on eastern African hydroclimate in the Pleistocene - Lupien, Rachel L.; Russell, James M.; Pearson, Emma J.; Castañeda, Isla S.; Asrat, Asfawossen; Foerster, Verena; Lamb, Henry F.; Roberts, Helen M.; Sch{abitz, Frank; Trauth, Martin H.; Beck, Catherine C.; Feibel, Craig S.; et al. (Scientific Reports, 2022)

Logging evaluation of deep multi-type unconventional gas reservoirs in the Songliao basin, northeast China: Implications from continental scientific drilling - Han, Shuangbiao; Xiang, Chaohan; Du, Xin; Xie, Linfeng; Bai, Songtao; Wang, Chengshan (Geoscience Frontiers, 2022)
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
Keywords: China; Songliao Basin; drilling; hydrocarbon exploration; hydrocarbon reservoir; logging (geophysics); natural gas; reservoir characterization

Mineralogy and structures below Deccan Traps: Evidences from scientific drilling in the Koyna seismogenic zone, India - Misra, Surajit; Goswami, Deepjyoti; Roy, Sukanta (Journal of Earth System Science, 2022)

Linking exhumation, paleo-relief, and rift formation to magmatic processes in the western Snake River Plain, Idaho, using apatite (U-Th)/He thermochronology - Wetzel, K.F.; Stanley, J.R. (Geosphere, 2022)
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.
cited By 0
Keywords: 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

Pleistocene climate variability in eastern Africa influenced hominin evolution - Foerster, Verena; Asrat, Asfawossen; Bronk Ramsey, Christopher; Brown, Erik T.; Chapot, Melissa S.; Deino, Alan; Duesing, Walter; Grove, Matthew; Hahn, Annette; Junginger, Annett; Kaboth-Bahr, Stefanie; Lane, Christine S.; et al. (Nature Geoscience, 2022)

Intensive peatland wildfires during the Aptian –Albian oceanic anoxic event 1b: Evidence from borehole SK-2 in the Songliao Basin, NE China - Zhang, Z.-H.; L{u, D.-W.; Wang, T.-T.; An, D.-Z.; Liu, H.-Y.; Wang, D.-D.; Wang, C.-S. (Journal of Palaeogeography, 2022)
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)
cited By 0

Koyna, India: A very prominent site of artificial water reservoir-triggered seismicity - Gupta, H.K. (Journal of Earth System Science, 2022)
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.
cited By 1
Keywords: borehole geophysics; earthquake event; human activity; laboratory method; reservoir; seismicity; India; Koyna Dam; Maharashtra

Large-scale, flat-lying mafic intrusions in the Baltican crust and their influence on basement deformation during the Caledonian orogeny - Lescoutre, Rodolphe; Almqvist, Bjarne; Koyi, Hemin; Berthet, Th'eo; Hedin, Peter; Galland, Olivier; Brahimi, Sonia; Lorenz, Henning; Juhlin, Christopher (GSA Bulletin, 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.

Late Quaternary hydroclimate of the Levant: The leaf wax record from the Dead Sea - Tierney, J.E.; Torfstein, A.; Bhattacharya, T. (Quaternary Science Reviews, 2022)
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
cited By 1
Keywords: 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

Life before impact in the Chicxulub area: unique marine ichnological signatures preserved in crater suevite - Rodr'iguez-Tovar, F.J.; Kaskes, P.; Orm{o, J.; Gulick, S.P.S.; Whalen, M.T.; Jones, H.L.; Lowery, C.M.; Bralower, T.J.; Smit, J.; King, Jr.; Goderis, S.; Claeys, P. (Scientific Reports, 2022)
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 Yucat'an Peninsula (M'exico) 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).
cited By 0

Listvenite formation during mass transfer into the leading edge of the mantle wedge: Initial results from Oman Drilling Project Hole BT1B - Kelemen, Peter B; Obeso, Juan; Leong, James A; Godard, Marguerite; Okazaki, Keishi; Kotowski, Alissa J; Manning, Craig E; Ellison, Eric T; Menzel, Manuel D; Urai, Janos L; et al. (Journal of Geophysical Research: Solid Earth, 2022)
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.
cited By 5
Keywords: carbon cycle; drilling; ductile deformation; mantle; mass transfer; ophiolite; subduction zone; ultramafic rock; Oman

Mid-latitude precipitation in East Asia influenced by a fluctuating greenhouse climate during the latest Cretaceous through the earliest Paleogene - Chen, Jiquan; Gao, Yuan; Ibarra, Daniel E.; Qin, Jianming; Wang, Chengshan (Global and Planetary Change, 2022)
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.
Keywords: 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

Logging evaluation of deep lacustrine shale reservoir in Songliao Basin: a case study of international continental scientific drilling; [松辽盆地深层陆相页岩储层测井评价：以国际大陆科学钻探为例] - Han, Shuangbiao; Du, Xin; Bai, Songtao; Wang, Chengshan (Zhongnan Daxue Xuebao (Ziran Kexue Ban)/Journal of Central South University (Science and Technology), 2022)
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.
Keywords: 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

Long-term preservation of Hadean protocrust in Earth's mantle - Tusch, Jonas; Hoffmann, J. Elis; Hasenstab, Eric; Fischer-G{odde, Mario; Marien, Chris S.; Wilson, Allan H.; M{unker, Carsten (Proceedings of the National Academy of Sciences of the United States of America, 2022)

Magnetostratigraphy of the Upper Cretaceous Nenjiang Formation in the Songliao Basin, northeast China: Implications for age constraints on terminating the Cretaceous Normal Superchron - Shen, Z.; Yu, Z.; Ye, H.; Deng, C.; He, H. (Cretaceous Research, 2022)
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
cited By 3
Keywords: accuracy assessment; age determination; borehole geophysics; chronostratigraphy; Cretaceous; error correction; geochronology; lithostratigraphy; magnetic susceptibility; magnetostratigraphy; uranium; uranium-lead dating; China; Songliao Basin

Major sulfur cycle perturbations in the Panthalassic Ocean across the Pliensbachian-Toarcian boundary and the Toarcian Oceanic Anoxic Event - Chen, Wenhan; Kemp, David B.; Newton, Robert J.; He, Tianchen; Huang, Chunju; Cho, Tenichi; Izumi, Kentaro (GLOBAL AND PLANETARY CHANGE, 2022)
Keywords: Early Toarcian; Panthalassic Ocean; Sulfur cycle; Pyrite sulfur isotope; Local sedimentary environment

Measurements of the inclination of the SE-03 Borehole on Surtsey Volcano - Weisenberger, Tobias B.; Guðmundsson, Magn'us Tumi; Gunnarsson, Bjarni Steinar; Jørgensen, Steffen L.; Jackson, M.D. (Surtsey research, 2022)

Microbial biosignature preservation in carbonated serpentine from the Samail Ophiolite, Oman - Lima-Zaloumis, Jon; Neubeck, Anna; Ivarsson, Magnus; Bose, Maitrayee; Greenberger, Rebecca; Templeton, Alexis S.; Czaja, Andrew D.; Kelemen, Peter B.; Edvinsson, Tomas (Communications Earth and Environment, 2022)

Microbial diversity and function in crystalline basement beneath the Deccan Traps explored in a 3 km borehole at Koyna, western India - Sahu, Rajendra Prasad; Kazy, Sufia K.; Bose, Himadri; Mandal, Sunanda; Dutta, Avishek; Saha, Anumeha; Roy, Sukanta; Dutta Gupta, Srimanti; Mukherjee, Abhijit; Sar, Pinaki (Environmental Microbiology, 2022)

Physical property studies to elucidate the source of seismic reflectivity within the ICDP DSeis seismogenic zone: Klerksdorp goldfield, South Africa - Nkosi, Nomqhele Z.; Manzi, Musa S.D.; Westgate, Michael; Roberts, Dave; Durrheim, Raymond J.; Ogasawara, Hiroshi; Ziegler, Martin; Rickenbacher, Michael; Liebenberg, Bennie; Onstott, Tullis C. (International Journal of Rock Mechanics and Mining Sciences, 2022)
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
Keywords: 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

Stress State in the Source Region of Mw2.2 Earthquake in a Deep Gold Mine in South Africa Determined from Borehole Cores - Yabe, Y.; Abe, S.; Hofmann, G.; Roberts, D.; Yilmaz, H.; Ogasawara, H.; Ito, T.; Funato, A.; Nakatani, M.; Naoi, M. (Pure and Applied Geophysics, 2022)
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).
cited By 0
Keywords: 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

Present situation and prospect of drilling and completion of 10000 meter scientific ultra deep wells (in Chinese with English abstract);[万米科学超深井钻完井现状与展望] - Wang, Z.; Wang, W.; Zhang, L.; Xi, Z.; An, D.; Yin, H.; Yan, J. (Science & Technology Review, 2022)

The post-Caledonian thermo-tectonic evolution of Fennoscandia - Green, Paul F.; Japsen, Peter; Bonow, Johan M.; Chalmers, James A.; Duddy, Ian R.; Kukkonen, Ilmo T. (Gondwana Research, 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.
Keywords: Exhumation; AFTA; Craton; Missing section; Peneplain

Subaqueous event deposits response to regional neotectonics: Case studies of the Dead Sea Basin and the Qaidam Basin - Lu, Y.; Wetzler, N.; Marco, S.; Fang, X. (Quaternary Sciences, 2022)
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.
cited By 0

Sulfate (re-) cycling in the oceanic crust: Effects of seawater-rock interaction, sulfur reduction and temperature on the abundance and isotope composition of anhydrite - Kleine, Barbara I; Stef'ansson, Andri; Zierenberg, Robert A; Jeon, Heejin; Whitehouse, Martin J; J'onasson, Kristj'an; Fridleifsson, Gudmundur 'O; Weisenberger, Tobias B (Geochimica et Cosmochimica Acta, 2022)

Syn-rift to post-rift tectonic transition and drainage reorganization in continental rifting basins: Detrital zircon analysis from the Songliao Basin, NE China - Song, Ying; Ren, Jianye; Liu, Keyu; Lyu, Dawei; Feng, Xinjie; Liu, Yuan; Stepashko, Andrei (Geoscience Frontiers, 2022)

Terrestrial heat flow and its geodynamic implications in the northern Songliao Basin, Northeast China - Shi, Y.; Jiang, G.; Shi, S.; Wang, Z.; Wang, S.; Hu, S. (Geophysical Journal International, 2022)
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).
cited By 1
Keywords: 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

The Chicxulub impact and its environmental consequences - Morgan, Joanna; Bralower, Timothy J.; Brugger, Julia; Wuennemann, Kai (NATURE REVIEWS EARTH & ENVIRONMENT, 2022)
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.
cited By 6

The Effect of Correlated Permeability on Fluid-Induced Seismicity - Khajehdehi, Omid; Karimi, Kamran; Davidsen, J{orn (Geophysical Research Letters, 2022)

The remanent magnetisation recorded in the Chesapeake Bay impact crater, Virginia - Supakulopas, R.; Tikoo, S.M. (Journal of Physics: Conference Series, 2022)
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.
cited By 0
Keywords: Rocks; Chesapeake Bay; High pressure; Impact craters; Impact events; Impact heating; Natural remanent magnetization; Planetary bodies; Recrystallisation; Remanent magnetization; Virginia; Magnetization

Stratigraphic record reveals contrasting roles of overflows and underflows over glacial cycles in a hypersaline lake (Dead Sea) - Lu, Y.; Pope, E.L.; Moernaut, J.; Bookman, R.; Waldmann, N.; Agnon, A.; Marco, S.; Strasser, M. (Earth and Planetary Science Letters, 2022)
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 <ρwater), and link graded turbidites and debrites to underflows (ρflow >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)
cited By 1
Keywords: 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

Thermal conductivity of Deccan flood basalts - Podugu, Nagaraju; Roy, Sukanta (Journal of Earth System Science, 2022)

Thermal History of Lithosphere Formed Beneath Fast Spreading Ridges: Constraints From the Mantle Transition Zone of the East Pacific Rise at Hess Deep and Oman Drilling Project, Wadi Zeeb, Samail Ophiolite - Grambling, Nadine L; Dygert, Nicholas; Boring, Beau; Jean, Marlon M; Kelemen, Peter B (Journal of Geophysical Research: Solid Earth, 2022)
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.
cited By 3
Keywords: gabbro; hydrothermal alteration; mantle source; ophiolite; seafloor spreading; temperature anomaly; thermometry; trace element; East Pacific Rise; Hess Deep; Pacific Ocean

Transformation of low-molecular-weight organic acids by microbial endoliths in subsurface mafic and ultramafic igneous rock - Fones, Elizabeth M.; Templeton, Alexis S.; Mogk, David W.; Boyd, Eric S. (Environmental Microbiology, 2022)

Triprojectacites in the Songliao Basin, Northeast China: Systematics, biostratigraphy and evolution - Wu, Yixiao; Li, Jianguo; Lin, Miaoqin; Koppelhus, Eva (Cretaceous Research, 2022)

Vegetation history of a Mexican Neotropical basin from the late MIS 6 to early MIS 3: The pollen record of Lake Chalco - Lozano-Garc'ia, S.; Torres-Rodr'iguez, E.; Figueroa-Rangel, B.; Caballero, M.; Sosa-N'ajera, S.; Ortega-Guerrero, B.; Acosta-Noriega, C. (Quaternary Science Reviews, 2022)
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
cited By 1
Keywords: 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

Volcanic tremor associated with the Surtsey eruption of 1963 –1967 - Sayyadi, S.; Gudmundsson, M. T.; Einarsson, P. (J{okull, 2022)

ICDP research drilling in the Moodies Group of the Barberton Greenstone Belt is underway - Heubeck, Christoph; Beukes, Nick; BASE Onsite Geoscience Team (Geobulletin, 2022)

Study of fluid circulation through the chicxulub crater using Rock-Eval pyrolysis and fluid inclusions - Hern'andez-Terrones, L.; Mart'inez, L.; Szamotulski, J.; Gonz'alez-Partida, E.; Morgan, J.V.; Lowery, C.M.; Gulick, S.P.S.; Rebolledo-Vieyra, M.; Kring, D. (Applied Geochemistry, 2022)
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
cited By 0

Spectroscopic study of terrestrial analogues to support rover missions to Mars – A Raman-centred review - Rull, Fernando; Veneranda, Marco; Manrique-Martinez, Jose Antonio; Sanz-Arranz, Aurelio; Saiz, Jesus; Medina, Jes'us; Moral, Andoni; Perez, Carlos; Seoane, Laura; Lalla, Emmanuel; Charro, Elena; Lopez, Jose Manuel; et al. (Analytica Chimica Acta, 2022)

Progressive veining during peridotite carbonation: insights from listvenites in Hole BT1B, Samail ophiolite (Oman) - Menzel, M.D.; Urai, J.L.; Ukar, E.; Decrausaz, T.; Godard, M. (Solid Earth, 2022)
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.
cited By 0
Keywords: 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

Research and application of high−temperature drilling fluid designed for the continental scientific drilling project of Songliao Basin, China - Zheng, W.; Wu, X.; Huang, Y. (Energy Sources, Part A: Recovery, Utilization and Environmental Effects, 2022)
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.
cited By 3
Keywords: 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

Prospects of gas production from the vertically heterogeneous hydrate reservoirs through depressurization in the Mallik site of Canada - Lei, H.; Yang, Z.; Xia, Y.; Yuan, Y. (Energy Reports, 2022)
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)
cited By 5
Keywords: 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

Pyroclastic deposition in the Cretaceous Shahezi Formation (Well SK-2) Songliao Basin, China: Implications for tectonics and volcanism - Fu, Y.; Cheng, R.; Gao, Y.; Zhou, Y.; Xu, Z. (Geological Journal, 2022)
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.
cited By 1
Keywords: Cretaceous; graben; lithofacies; provenance; pyroclastic deposit; tectonics; transtension; Triassic; volcanism; weathering; China; Songliao Basin

Quaternary environmental changes in central Chukotka (NE Russia) inferred from the Lake El'gygytgyn pollen records - Zhao, W.; Andreev, A.A.; Wennrich, V.; Li, Q.; Melles, M. (Journal of Quaternary Science, 2022)
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.
cited By 1
Keywords: albedo; environmental change; glacial-interglacial cycle; ice; Milankovitch cycle; Pleistocene; pollen; snow; vegetation; Chukchi; Elgygytgyn Lake; Russian Federation

Reconstructing the Environmental Context of Human Origins in Eastern Africa Through Scientific Drilling - Cohen, Andrew S.; Campisano, Christopher J.; Arrowsmith, J. Ramo acute n; Asrat, Asfawossen; Beck, Catherine C.; Behrensmeyer, Anna K.; Deino, Alan L.; Feibel, Craig S.; Foerster, Verena; Kingston, John D.; Lamb, Henry F.; Lowenstein, Tim K.; et al. (Annual Review of Earth and Planetary Sciences, 2022)
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.
Keywords: 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

Reconstructing the Environmental Context of Human Origins in Eastern Africa Through Scientific Drilling - Cohen, Andrew S.; Campisano, Christopher J.; Arrowsmith, J. Ramo acute n; Asrat, Asfawossen; Beck, Catherine C.; Behrensmeyer, Anna K.; Deino, Alan L.; Feibel, Craig S.; Foerster, Verena; Kingston, John D.; Lamb, Henry F.; Lowenstein, Tim K.; et al. (Annual Review of Earth and Planetary Sciences, 2022)

Reduced plate motion controlled timing of Early Jurassic Karoo-Ferrar large igneous province volcanism - Ruhl, Micha; Hesselbo, Stephen P.; Jenkyns, Hugh C.; Xu, Weimu; Silva, Ricardo L.; Matthews, Kara J.; Mather, Tamsin A.; Mac Niocaill, Conall; Riding, James B. (SCIENCE ADVANCES, 2022)

Research progress of absorption and attenuation mechanism and petrophysical theory for gas hydrate reservoir [天然气水合物储层吸收衰减机制及岩石物理理论研究进展] - Wu, C.; Zhang, F.; Li, X. (Shiyou Diqiu Wuli Kantan/Oil Geophysical Prospecting, 2022)
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.
cited By 0
Keywords: 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

Ship-board determination of whole-rock (ultra-)trace element concentrations by laser ablation-inductively coupled plasma mass spectrometry analysis of pressed powder pellets aboard the D/V Chikyu - Rospab'e, M.; Kourim, F.; Tamura, A.; Takazawa, E.; Giampouras, M.; Chatterjee, S.; Ishii, K.; Cooper, M.J.; Godard, M.; Carter, E.; Abe, N.; Moe, K.; et al. (Scientific Drilling, 2022)
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 Rospab'e et al.
cited By 1
Keywords: 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

Resolving impact volatilization and condensation from target rock mixing and hydrothermal overprinting within the Chicxulub impact structure - D'ehais, T.; Chernonozhkin, S.M.; Kaskes, P.; Graaff, S.J.; Debaille, V.; Vanhaecke, F.; Claeys, P.; Goderis, S. (Geoscience Frontiers, 2022)
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 ( >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
cited By 0

Revisiting the Milankovitch Theory from the Perspective of the 405 ka Long Eccentricity Cycle; [从40万年长偏心率周期看米兰科维奇理论] - Tian, Jun; Wu, Huaichun; Huang, Chunju; Li, Mingsong; Ma, Chao; Wang, Pinxian (Diqiu Kexue - Zhongguo Dizhi Daxue Xuebao/Earth Science - Journal of China University of Geosciences, 2022)

Rhodothermus bifroesti sp. nov., a thermophilic bacterium isolated from the basaltic subsurface of the volcanic island Surtsey - Bergsten, Pauline; Vannier, Pauline; Mougeolle, Alan; Rigaud, Louise; Marteinsson, Vigg'o Th'or (International Journal of Systematic and Evolutionary Microbiology, 2022)

Search for a meteoritic component within the impact melt rocks of the Chicxulub impact structure peak ring, Mexico - Feignon, J.-G.; Schulz, T.; Ferrière, L.; Goderis, S.; Graaff, S.J.; Kaskes, P.; D'ehais, T.; Claeys, P.; Koeberl, C. (Geochimica et Cosmochimica Acta, 2022)
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 ( <39 ppt Ir, <96 ppt Os, <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)
cited By 2

Sediment provenance and silicic volcano-tectonic evolution of the northern East African Rift System from U/Pb and (U-Th)/He laser ablation double dating of detrital zircons - Zawacki, Emily E.; Soest, Matthijs C.; Hodges, Kip V.; Scott, Jennifer J.; Barboni, M'elanie; Strecker, Manfred R.; Feibel, Craig S.; Campisano, Christopher J.; Arrowsmith, J. Ram'on (Earth and Planetary Science Letters, 2022)
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.
Keywords: 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

SediRate-Fischer plots as a tool to illustrate relative sea-level and lake-level changes in subaqueous terrigenous deposits - Yang, Daming; Huang, Yongjian; Wang, Chengshan (Sedimentology, 2022)
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 Gibrale'on 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 Gibrale'on 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.
Keywords: 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

Sensitivity of the West Antarctic Ice Sheet to+ 2° C (SWAIS 2C) - Patterson, Molly O; Levy, Richard H; Kulhanek, Denise K; van de Flierdt, Tina; Horgan, Huw; Dunbar, Gavin B; Naish, Timothy R; Ash, Jeanine; Mandeno, Darcy; et al. (Scientific Drilling, 2022)

Intensified microbial sulfate reduction in the deep Dead Sea during the early Holocene Mediterranean sapropel 1 deposition - Levy, E.J.; Thomas, C.; Antler, G.; Gavrieli, I.; Turchyn, A.; Grossi, V.; Ariztegui, D.; Sivan, O. (Geobiology, 2022)
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.
cited By 0
Keywords: 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

Paleoenvironmental evolution during the Early Eocene Climate Optimum in the Chicxulub impact crater - Schaefer, Bettina; Schwark, Lorenz; B{ottcher, Michael E.; Smith, Vann; Coolen, Marco J. L.; Grice, Kliti (EARTH AND PLANETARY SCIENCE LETTERS, 2022)
Keywords: biomarker; C/N/S-stable isotopes; TEX86; primary productivity; paleosalinity; pigments

ICDP Oman Drilling Project: varitextured gabbros from the dike–gabbro transition within drill core GT3A - Engelhardt, Artur; Koepke, J{urgen; Zhang, Chao; Garbe-Sch{onberg, Dieter; Jesus, Ana Patr'ıcia (European Journal of Mineralogy, 2022)

Biomarker proxy records of Arctic climate change during the Mid-Pleistocene transition from Lake El'gygytgyn (Far East Russia) - Lindberg, K.R.; Daniels, W.C.; Castañeda, I.S.; Brigham-Grette, J. (Climate of the Past, 2022)
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 skippedinterglacial. 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.
cited By 3
Keywords: biomarker; climate change; glacial-interglacial cycle; Pleistocene; vegetation cover; warming; Chukchi; Elgygytgyn Lake; Russian Federation

Archaeal lipids reveal climate-driven changes in microbial ecology at Lake El'gygytgyn (Far East Russia) during the Plio-Pleistocene - Daniels, W.C.; Castañeda, I.S.; Salacup, J.M.; Habicht, M.H.; Lindberg, K.R.; Brigham-Grette, J. (Journal of Quaternary Science, 2022)
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.
cited By 3
Keywords: 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

Artificial Water Reservoir-Triggered Seismicity (RTS): Most Prominent Anthropogenic Seismicity - Gupta, H.K. (Surveys in Geophysics, 2022)
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.
cited By 3
Keywords: 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

Beneath shaky ground: deep life at Koyna, India - Kieft, Thomas L. (Environmental Microbiology, 2022)

Benthic-Pelagic state changes in the primary trophic level of an ancient tropical lake - Ageli, Mariam K.; Hamilton, Paul B.; Bramburger, Andrew J.; Weidman, R. Paul; Song, Zhuoyan; Russell, James; Bijaksana, Satria; Haffner, G. Douglas (Palaeogeography, Palaeoclimatology, Palaeoecology, 2022)
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
Keywords: Greater Sunda Islands; Lake Towuti; Malili Lakes; South Sulawesi; Sulawesi; Sunda Isles; benthic-pelagic coupling; plankton; primary production; sediment chemistry; trophic level

Big volcano science: needs and perspectives - Papale, P.; Garg, D. (Bulletin of Volcanology, 2022)
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).
cited By 1
Keywords: magma; volcano; volcanology

Bimodal alteration of the oceanic crust revealed by halogen and noble gas systematics in the Oman Ophiolite - Carter, Elliot J; O’Driscoll, Brian; Burgess, Ray; Clay, Patricia L; Hepworth, James; Team, Oman Drilling Project Science (Journal of Geophysical Research: Solid Earth, 2022)

Borehole logging and seismic data from Lake Ohrid (North Macedonia/Albania) as a basis for age-depth modelling over the last one million years - Ulfers, A.; Zeeden, C.; Wagner, B.; Krastel, S.; Buness, H.; Wonik, T. (Quaternary Science Reviews, 2022)
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
Keywords: 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

Application of machine learning to characterize gas hydrate reservoirs in Mackenzie Delta (Canada) and on the Alaska north slope (USA) - Chong, L.; Singh, H.; Creason, C.G.; Seol, Y.; Myshakin, E.M. (Computational Geosciences, 2022)
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.
cited By 1
Keywords: artificial neural network; gas hydrate; hydrocarbon reservoir; hydrocarbon resource; machine learning; nuclear magnetic resonance; Canada; Mackenzie Delta; Northwest Territories

Borehole Seismic Observations From the Chicxulub Impact Drilling: Implications for Seismic Reflectivity and Impact Damage - Nixon, C.G.; Kofman, R.; Lofi, J.; Gulick, S.P.S.; Saustrup, S.; Christeson, G.L.; Kring, D.A. (Geochemistry, Geophysics, Geosystems, 2022)
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.
cited By 0

Characteristics of Fault Rocks Within the Aftershock Cloud of the 2014 Orkney Earthquake (M5.5) Beneath the Moab Khotsong Gold Mine, South Africa - Miyamoto, T.; Hirono, T.; Yokoyama, Y.; Kaneki, S.; Yamamoto, Y.; Ishikawa, T.; Tsuchiyama, A.; Katayama, I.; Yabe, Y.; Durrheim, R. J.; Ogasawara, H. (Geophysical Research Letters, 2022)
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.
e2022GL098745 2022GL098745
Keywords: earthquake; fault drilling; lamprophyre

Chemical weathering characteristics of the Late Cretaceous Nenjiang Formation from the Songliao Basin (Northeastern China) reveal prominent Milankovitch band variations - Li, Xiang; Huang, Yongjian; Zhang, Zhifeng; Wang, Chengshan (Palaeogeography, Palaeoclimatology, Palaeoecology, 2022)
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
Keywords: China; Songliao Basin; chemical weathering; clastic sediment; correlation; Cretaceous; hydrological cycle; paleoclimate; spectral analysis

Chicxulub Crater Joint Gravity and Magnetic Anomaly Analysis: Structure, Asymmetries, Impact Trajectory and Target Structures - Urrutia-Fucugauchi, J.; Arellano-Catal'an, O.; P'erez-Cruz, L.; Romero-Galindo, I.A. (Pure and Applied Geophysics, 2022)
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.
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Climatic Controls on a Holocene Mercury Stable Isotope Sediment Record of Lake Titicaca - Jiskra, Martin; Gu'edron, St'ephane; Tolu, Julie; Fritz, Sherilyn C.; Baker, Paul A.; Sonke, Jeroen E. (ACS Earth and Space Chemistry, 2022)
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
Keywords: Lake Titicaca; atmospheric deposition; biogeochemistry; biomarker; climate change; erosion; geological record; Holocene; mercury (element); sediment core; stable isotope

Complex Crater Formation by Oblique Impacts on the Earth and Moon - Davison, T.M.; Collins, G.S. (Geophysical Research Letters, 2022)
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.
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Convective Melting and Water Behavior around Magmatic-Hydrothermal Transition: Numerical Modeling with Application to Krafla Volcano, Iceland - Simakin, A.G.; Bindeman, I.N. (Journal of Petrology, 2022)

Application of SPAC Method to Survey Deep Geothermal Water Storage Structures in SK-2; [基于SPAC法探测松科二井深层地热储水构造] - Ying, Heng-Cheng; Li, Hong-Qiang; Zhang, Yu-Min; Jin, Zhong-Yuan; Zhang, Jia-Duo; Fu, Wei; Gao, Lei; An, Dong-Zhao; Pan, Zong-Dong; Wang, Wei; Hou, He-Sheng (Acta Geoscientica Sinica, 2022)
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.

Application of Long-Tube Coring Technique in Quantou Formation of SK-3 well (in Chinese); 长筒取芯技术在松科三井泉头组地层的应用 - Li, C; Cheng, B.; Zhang, S.; Zhang, H. (West-China Exploration Engineering, 2022)

Culturable Bacterial Diversity from the Basaltic Subsurface of the Young Volcanic Island of Surtsey, Iceland - Bergsten, Pauline; Vannier, Pauline; Frion, Julie; Mougeolle, Alan; Marteinsson, Vigg'o Th'or (Microorganisms, 2022)

A low-temperature, meteoric water-dominated origin for smectitic clay minerals in the Chicxulub impact crater upper peak ring, as inferred from their oxygen and hydrogen isotope compositions - Simpson, S.L.; Longstaffe, F.J.; Osinski, G.R.; Caudill, C.M.; Kring, D.A. (Chemical Geology, 2022)
The peak-ring of the 66 Ma, 180 km Chicxulub impact structure in the northern Yucat'an 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 <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 Yucat'an 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.
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ICDP drilling of the Eger Rift observatory: magmatic fluids driving the earthquake swarms and deep biosphere - Fischer, Tom'aš; Hrubcov'a, Pavla; Dahm, Torsten; Woith, Heiko; Vylita, Tom'aš; Ohrnberger, Matthias; Vlček, Josef; Hor'alek, Josef; Dědeček, Petr; Lipus, Martin P.; Kallmeyer, Jens; Kruger, Frank; et al. (Scientific Drilling, 2022)

700,000 years of tropical Andean glaciation - Rodbell, D.T.; Hatfield, R.G.; Abbott, M.B.; Chen, C.Y.; Woods, A.; Stoner, J.S.; McGee, D.; Tapia, P.M.; Bush, M.; Valero-Garc'es, B.L.; Lehmann, S.B.; Mark, S.Z.; et al. (Nature, 2022)
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 Jun'in 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).
Keywords: Greenland; Ice Cover; Temperature; Amazon River; Arctic; Greenland; glaciation; monsoon; Pleistocene; teleconnection; article; glaciation; Greenland; information center; periodicity; precipitation; ice cover; temperature

86Kr excess and other noble gases identify a billion-year-old radiogenically-enriched groundwater system - Warr, O.; Ballentine, C.J.; Onstott, T.C.; Nisson, D.M.; Kieft, T.L.; Hillegonds, D.J.; Sherwood Lollar, B. (Nature Communications, 2022)
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 >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).
cited By 2
Keywords: 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

A Four-Phase Model for Methane Production from an Unconsolidated Hydrate Reservoir. Part 2. Numerical Simulation - Hinz, D.; Arastoopour, H.; Abbasian, J. (Industrial and Engineering Chemistry Research, 2022)
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.
cited By 0
Keywords: 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

A geochronologically-constrained stable isotope record of the Upper Triassic Sonsela Member (Chinle Formation) at Petrified Forest National Park (Arizona, USA): Testing for paleoenvironmental linkages with biotic change and the Manicouagan impact - Rasmussen, C.; Irmis, R.B.; Mundil, R.; Schaller, M.F.; Geissman, J.; Parker, W.G.; Lepre, C.J.; Olsen, P.E. (Palaeogeography, Palaeoclimatology, Palaeoecology, 2022)
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.
cited By 0
Keywords: geochronology; historical record; paleoclimate; paleoenvironment; preservative; proxy climate record; stable isotope; Triassic; Arizona; United States

A Late Pleistocene (MIS4-MIS2) palaeohydrological reconstruction from Lake Chalco, Basin of Mexico - Ch'avez-Lara, C.M.; Lozano-Garc'ia, S.; Ortega-Guerrero, B.; Avendaño, D.; Caballero-Miranda, M. (Journal of South American Earth Sciences, 2022)
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
cited By 2
Keywords: environmental change; evapotranspiration; ostracod; paleohydrology; Pleistocene; salinity; warming; water level; Lake Chalco; Mexico [North America]

A Reference Section Through Fast-Spread Lower Oceanic Crust, Wadi Gideah, Samail Ophiolite (Sultanate of Oman): Whole Rock Geochemistry - Garbe-Sch{onberg, D.; Koepke, J.; M{uller, S.; Mock, D.; M{uller, T. (Journal of Geophysical Research: Solid Earth, 2022)
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.
cited By 1
Keywords: gabbro; geochemistry; oceanic crust; seafloor spreading; trace element; transect; Oman; Semail Ophiolite

Application of elemental capture spectroscopy in deep tight reservoir evaluation: A case study of well SK-2; [元素俘获能谱在深层致密储层评价中的应用: 以松科2井为例] - Han, Shuangbiao; Tang, Zhiyuan; Bai, Songtao; Wan, Lei; Rui, Yurun; Gao, Yuan; Huang, Yongjian; Wang, Chengshan (Earth Science Frontiers, 2022)
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.
Keywords: 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

A stronger role for long-term moisture change than for CO2 in determining tropical woody vegetation change - Gosling, William D.; Miller, Charlotte S.; Shanahan, Timothy M.; Holden, Philip B.; Overpeck, Jonathan T.; Langevelde, Frank (Science, 2022)

A Study on the Sedimentation Rate of the Denglouku Formation from CCSD SK-2, Based on Logging Spectral Analysis [基于测井频谱分析的松科二井登娄库组地层沉积速率研究] - Zhang, H.-D.; Zou, C.-C.; Peng, C.; Yang, Y.-Q. (Acta Geoscientica Sinica, 2022)
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.
cited By 0

A Trial Evaluation of Rock Core DCDA Absolute Differential Stress Measurement for Routine Quantitative Mining Hazard Assessment in Deep Underground High Stress Mines; [研精覃 ?， ?微知著-人工智能开 ? 精准病 ? 诊断新时代] - Ogasawara, Hiroshi; Mima, Yoshihiro; Ishida, Akimasa; Mngadi, Siyanda; Higashi, Mitsuya; Yabe, Yasuo; Funato, Akio; Ito, Takatoshi; Nakatani, Masao; Durrheim, Raymond (Zairyo/Journal of the Society of Materials Science, Japan, 2022)

Alteration of basaltic glass within the Surtsey hydrothermal system, Iceland – Implication to oceanic crust seawater interaction - Prause, S.; Weisenberger, T.B.; Kleine, B.I.; Monien, P.; Rispoli, C.; Stef'ansson, A. (Journal of Volcanology and Geothermal Research, 2022)
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.
cited By 0
Keywords: 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

An astronomical age-depth model and reconstruction of moisture availability in the sediments of Lake Chalco, central Mexico, using borehole logging data - Sardar Abadi, M.; Zeeden, C.; Ulfers, A.; Wonik, T. (Quaternary Science Reviews, 2022)
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
cited By 0
Keywords: 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]