All ICDP Publications with Abstracts
From parent-sysfolder "Publications" + 2 folder-levels deep
2319.
Geophysical Borehole Observatory at the North Anatolian Fault in the Eastern Sea of Marmara (GONAF): initial results
Journal of Seismology,
24
(2)
375 – 395
2020
ISSN: 13834649
Publisher: Springer
Keywords:▾
Sea of Marmara; Turkey; borehole geophysics; Coulomb criterion; earthquake damage; earthquake magnitude; geophysical method; seismograph; seismology
Abstract: ▾ Given its intense seismic activity and damaging earthquake generation potential, the western part of the North Anatolian Fault constitutes a serious natural hazard. As a result, the fault is monitored with a broad range of seismological and geodetic instrumentation making it a natural laboratory environment for scientific studies. One of the long-term projects in this region is GONAF (Geophysical Borehole Observatory at the North Anatolian Fault) which is the first borehole seismometer network project in Turkey. GONAF is a joint research project that started in 2011 as joint initiative of the Turkish Ministry of Interior, Disaster and Emergency Management Presidency AFAD and GFZ and the German Research Center for Geoscience Helmholtz Center Potsdam. The aim of GONAF is to detect, examine, and monitor the microseismic activity in the region and to observe the physical processes before, during and after a large Marmara earthquake (M > 7.0) that is expected to rupture the western part of the North Anatolian Fault, below the Marmara Sea along the Princes Islands segment or even further to the west. For this purpose, the permanent GONAF observatory was established consisting of 7 borehole seismometer arrays installed down to a depth of 300 m. In this paper, we report on regional stress changes in the western part of the North Anatolian Fault Zone (NAFZ) using instrumental data and the Coulomb stress method. We also present preliminary results of the observation and evaluation of microseismic activity obtained from the GONAF observatory. For the automatic evaluation of real-time data, Seiscomp3, RTQUAKE, and Earthworm Softwares were used. Within the scope of automatic earthquake detection studies, between March, 2016 and November, 2017, a total of 2568 earthquakes were detected using the RTQUAKE software. Of these, 1459 could be analyzed. While the magnitude of the analyzed earthquakes varies between 0.8 and 4.2, the depth of these events ranges from 2 to 30 km. © 2020, Springer Nature B.V.
2318.
{Explosive interaction of impact melt and seawater following the Chicxulub impact event}
Geology,
48
(2)
108-112
November2019
ISSN: 0091-7613DOI:10.1130/G46783.1
Abstract: ▾ {The impact of asteroids and comets with planetary surfaces is one of the most catastrophic, yet ubiquitous, geological processes in the solar system. The Chicxulub impact event, which has been linked to the Cretaceous-Paleogene (K-Pg) mass extinction marking the beginning of the Cenozoic Era, is arguably the most significant singular geological event in the past 100 million years of Earth’s history. The Chicxulub impact occurred in a marine setting. How quickly the seawater re-entered the newly formed basin after the impact, and its effects of it on the cratering process, remain debated. Here, we show that the explosive interaction of seawater with impact melt led to molten fuel–coolant interaction (MFCI), analogous to what occurs during phreatomagmatic volcanic eruptions. This process fractured and dispersed the melt, which was subsequently deposited subaqueously to form a series of well-sorted deposits. These deposits bear little resemblance to the products of impacts in a continental setting and are not accounted for in current classification schemes for impactites. The similarities between these Chicxulub deposits and the Onaping Formation at the Sudbury impact structure, Canada, are striking, and suggest that MFCI and the production of volcaniclastic-like deposits is to be expected for large impacts in shallow marine settings.}
2317.
Practice of turbodrill core drilling in well SK-2 (in Chinese with English abstract);[松科2井带涡轮钻具取心钻进探索]
Drilling & Production Technology,
42
(01)
31-34+3
2019
2316.
Progress on Continental Scientific Drilling Project of Cretaceous Songliao Basin (SK-1 and SK-2)
Science Bulletin,
64
(2)
73-75
2019
ISSN: 20959273
Publisher: Elsevier B.V.
2315.
Project Report: Grinding Through the Ediacaran-Cambrian Transition
Communications of the Geological Survey of Namibia,
211-14
2019
2314.
Provenance and tectonic implications of the 3.28–3.23 Ga Fig Tree Group, central Barberton greenstone belt, South Africa
Precambrian Research,
3251 – 19
2019
2313.
Q value analysis of deep seismic reflection data of Well SK-2 and its determination of gas-bearing stratum; [松科二井深地震反射数据 Q值分析及其对含气层位的确定]
Geology in China,
46
(5)
1137 – 1145
2019
ISSN: 10003657
Publisher: Science Press
Abstract: ▾ When the seismic wave propagates in the underground media, the seismic wave energy will show a certain degree of attenuation. The quality factor Q is an important parameter for measuring the absorption and attenuation properties of the underground rock, and is of great significance for describing the lithological characteristics and predicting the oil and gas distribution. In this paper, the Q value analysis technique based on S transformation ratio method for deep seismic reflection data was developed, and the more accurate Q value was obtained. Taking the Shahezi Formation in the Songliao Basin as the main target layer, the authors calculated the Q value of the post-stack deep seismic reflection profile across Well SK-2, and then generated the Q value profile to summarize Q value distribution characteristics of the Shahezi Formation. The Q value distribution characteristics, combined with the logging, stratification and gas anomaly data of Well SK-2, suggest that the Shahezi Formation is a gas reservoir, and this discovery provides a way for the next deep reservoir prediction. This conclusion provides an idea for the further deep reservoir prediction and can serve the deep geological survey project in Northeast China. © 2019 Editorial Board of Geology in China. All rights reserved.
2312.
Quantitative estimates of orbital and millennial scale climatic variability in central Mexico during the last ∼40,000 years
Quaternary Science Reviews,
20562-75
2019
ISSN: 02773791
Publisher: Elsevier Ltd
Keywords:▾
Glacial geology; Incident solar radiation; Lakes; Paleolimnology; Tropics, Diatoms; Late Pleistocene; Micropaleontology; Monsoon; North America; Paleoclimatology, Transfer functions, climate variation; diatom; micropaleontology; monsoon; paleoclimate; paleolimnology; paleotemperature; Pleistocene; precipitation (climatology); quantitative analysis; salinity; transfer function, Atlantic Ocean; Atlantic Ocean (North); Guatemala [Central America]; Lake Peten Itza; Mexico [North America]; Peten; Valley of Mexico, Bacillariophyta
Abstract: ▾ Diatom-based transfer functions for salinity, precipitation and temperature were developed using a training set that included data from 40 sites along central Mexico. These transfer functions showed good performance parameters and were subsequently applied to the previously published diatom record from lake Chalco, southern Basin of Mexico. Heinrich stadials (HS-3 to HS-0) were reconstructed as cold and dry events, with HS-2 representing the coldest and driest conditions, while HS-1 shows a complex bimodal cooling pattern. Orbital scale variability is also recorded. High and variable lake salinities from ∼34 to 29 ka BP (marine isotope stage 3, MIS-3) corresponded with times of maximum summer insolation and evidences of frequent fires. MIS-2 was identified as a cold period, with low lake salinity associated with low evaporation, with two cold intervals during the minima in spring (∼25.5 ka BP) and summer (∼20 ka BP) insolation. The ∼20 ka BP cold event together with HS-2 (24-23 ka BP), defined a bimodal maximum cooling during the last glacial maximum (LGM: 24.5–19.5 ka BP) within the range of pollen-based estimates, further supporting a maximum tropical cooling of 4–5 °C for the LGM. The deglacial (19.5–11.5 ka BP) showed the highest precipitation anomalies with three peaks that closely correlated with glacier advances in the nearby mountains (Iztaccihuatl). The early Holocene marked a change towards high lake salinities and the highest positive temperature anomalies (+3.5 °C) during a peak in summer insolation. Even though at orbital scale Chalco showed a nearly opposite trend to the record from the more southerly lake Peten-Itza (Guatemala), at millennial scale it showed a common pattern of cold and dry conditions during HSs, comparable to other tropical latitude sites in the northern hemisphere and further supporting the idea that there is a strong coupling between tropical and higher latitudes climates, in particular with the North Atlantic. © 2018 Elsevier Ltd
2311.
Remnants of paleoflora in impact melt rocks of the El'gygytgyn crater (Chukotka, Russia)
Meteoritics and Planetary Science,
54
(10)
2532-2540
2019
ISSN: 10869379
Publisher: University of Arkansas
Abstract: ▾ Remnants of paleoflora were discovered in impact melt rocks from the El'gygytgyn crater, Chukotka, Russia. El'gygytgyn is a 3.58 Ma, 18 km diameter impact structure in Chukotka, northeastern Russia. A circular crater basin is surrounded by an uplifted rim. The crater floor is occupied by the El'gygytgyn Lake, 12 km in diameter, surrounded by lacustrine terraces up to 80 m in height. Impactites found at the El'gygytgyn crater include impact melt rocks, glass bombs, and shock metamorphosed volcanic rocks. Most impact melt rocks occur only in redeposited state in the terrace lake deposits. Floral remnants were discovered in impact melt rocks from various locations in the terrace deposits. The floral remnants include fragments of leaves, cell tissue, and undetermined organic matter that occur in vesicles within glassy melt rocks and impact melt breccias. After the discovery of floral remnants in impact melt breccias from upper Miocene strata in Argentina, and the description of floral imprints in the Dakhleh Glass of proposed impact origin in Egypt, the detection of paleoflora remnants in impact melt rocks of the El'gygytgyn structure is the first such occurrence in a confirmed impact crater on Earth. © 2019 The Authors. Meteoritics & Planetary Science published by Wiley Periodicals, Inc. on behalf of The Meteoritical Society (MET).
2310.
Quaternary history of the Lake Magadi Basin, southern Kenya Rift: Tectonic and climatic controls
Palaeogeography, Palaeoclimatology, Palaeoecology,
51897 – 118
2019
2309.
Raw IRM measurements of composite sediment core ICDP5045-1 from Lake Ohrid, Balkans
PANGAEA
2019
2308.
Re-evaluating the age of deep biosphere fossils in the lockne impact structure
Geosciences (Switzerland),
9
(5)
2019
Abstract: ▾ Impact-generated hydrothermal systems have been suggested as favourable environments for deep microbial ecosystems on Earth, and possibly beyond. Fossil evidence from a handful of impact craters worldwide have been used to support this notion. However, as always with mineralized remains of microorganisms in crystalline rock, certain time constraints with respect to the ecosystems and their subsequent fossilization are difficult to obtain. Here we re-evaluate previously described fungal fossils from the Lockne crater (458 Ma), Sweden. Based on in-situ Rb/Sr dating of secondary calcite-albite-feldspar (356.6 ± 6.7 Ma) we conclude that the fungal colonization took place at least 100 Myr after the impact event, thus long after the impact-induced hydrothermal activity ceased. We also present microscale stable isotope data of13C-enriched calcite suggesting the presence of methanogens contemporary with the fungi. Thus, the Lockne fungi fossils are not, as previously thought, related to the impact event, but nevertheless have colonized fractures that may have been formed or were reactivated by the impact. Instead, the Lockne fossils show similar features as recent findings of ancient microbial remains elsewhere in the fractured Swedish Precambrian basement and may thus represent a more general feature in this scarcely explored habitat than previously known. © 2019 by the authors. Licensee MDPI, Basel, Switzerland.
2307.
Recordings of Fast Paleomagnetic Reversals in a 1.2 Ma Greigite-Rich Sediment Archive From Lake Ohrid, Balkans
Journal of Geophysical Research: Solid Earth,
124
(12)
12445 – 12464
2019
2306.
Recycling of archaeal biomass as a new strategy for extreme life in Dead Sea deep sediments
Geology,
47
(5)
479 – 482
2019
DOI:10.1130/G45801.1
2305.
Refining the interpretation of lacustrine carbonate isotope records: Implications of a mineralogy-specific Lake Van case study
Chemical Geology,
513167-183
2019
ISSN: 00092541
Publisher: Elsevier B.V.
Keywords:▾
Calcite; Carbon; Carbonation; Electron probe microanalysis; Isotopes; Lakes; Oxygen; Refining; Repair; Scanning electron microscopy; Sedimentology; Sediments; Water; X ray powder diffraction, Carbonate precipitation; Confocal Raman microscopy; Diagenetics; Environmental reconstruction; Isotopic fractionations; Lake vans; Oxygen isotope composition; Palaeoenvironmental reconstruction, Carbonate minerals, aragonite; calcite; carbon isotope; carbonate; diagenesis; dolomite; isotopic composition; lacustrine deposit; mineralogy; oxygen isotope; paleoenvironment; reconstruction; sediment chemistry, Lake Van; Turkey
Abstract: ▾ Oxygen and carbon isotope (δ 18 O and δ 13 C) data from bulk carbonates are widely applied proxies for temperature, the precipitation/evaporation ratio and productivity in lacustrine palaeohydrology and palaeoclimatology. In case of the terminal and alkaline Lake Van, however, previous studies have shown that bulk oxygen isotope compositions are in disagreement with other proxies when interpreted in a conventional manner. Similarly, the reports on the nature and the timing and site of carbonate precipitation in Lake Van are inconsistent. This study provides evidence on the mineralogy (X-ray powder diffraction analysis, scanning electron microscope imaging, confocal Raman microscopy, electron microprobe analysis) and isotope composition (δ 18 O and δ 13 C) of non-skeletal carbonate minerals in a Lake Van sedimentary profile spanning the last ca. 150 kyr. Carbonate phases present in the sediment include aragonite, low-Mg calcite, and calcian dolomite. Dolomite forms as an early diagenetic phase and occurs episodically in high concentrations driving the bulk isotope record towards the higher dolomite δ 18 O and varying δ 13 C values. Aragonite and low-Mg calcite precipitate in the surface water and are present in the sediments in varying amounts (relative aragonite to calcite content for dolomite-poor samples Ar/(Ar + Cc) of 93 to 41 wt%). In an attempt to explain this variation, we revised a precipitation model based on annually laminated sediments containing both aragonite and calcite spatially separated in light and dark coloured laminae, respectively. According to our model, spring calcite precipitation, under close-to-freshwater conditions, is followed by evapoconcentration-driven aragonite precipitation in late summer. The precipitation of these carbonate polymorphs from chemically differing surface waters (i.e. freshwater-influenced and evapoconcentrated) leads to distinctly different oxygen and carbon isotope signatures between sedimentary penecontemporaneous aragonite and calcite. The δ 18 O and δ 13 C values of aragonite relative to calcite are significantly higher by several per mille than inferred from aragonite-calcite fractionation factors alone, suggesting that the generalised assumption of sedimentary coeval calcite and aragonite precipitating from water with the same isotopic composition is flawed. The here proposed revised hydrologically-separated carbonate precipitation model is not only taking (i) differences in the isotopic fractionation between carbonate minerals into account, but also (ii) considering the hydrological conditions and the processes favouring the precipitation of a given mineral and ultimately controlling its isotopic composition. If mixed mineralogies are present, this mineralogy-specific approach has the potential of refining environmental reconstructions and reconciling apparently equivocal interpretations of different proxy records. © 2019 The Authors
2304.
Refining the Late Quaternary tephrochronology for southern South America using the Laguna Potrok Aike sedimentary record
Quaternary Science Reviews,
218137 – 156
2019
Keywords:▾
Argentina; Laguna Potrok Aike; Patagonia; Santa Cruz [Argentina]; Southern Volcanic Zone; Deposits; Geochemistry; Glass; Minerals; Sedimentology; Stratigraphy; Lacustrine; PASADO; Patagonia; Quaternary; South America; Tephrochronology; Volcanic ash; emplacement; geochemistry; lacustrine environment; Quaternary; reworking; sediment chemistry; sedimentary sequence; stratigraphy; tephrochronology; volcanic ash; volcanic eruption; volcanism; volcano; Volcanoes
Abstract: ▾ This paper presents a detailed record of volcanism extending back to ∼80 kyr BP for southern South America using the sediments of Laguna Potrok Aike (ICDP expedition 5022; Potrok Aike Maar Lake Sediment Archive Drilling Project - PASADO). Our analysis of tephra includes the morphology of glass, the mineral componentry, the abundance of glass-shards, lithics and minerals, and the composition of glass-shards in relation to the stratigraphy. Firstly, a reference database of glass compositions of known eruptions in the region was created to enable robust tephra correlations. This includes data published elsewhere, in addition to new glass-shard analyses of proximal tephra deposits from Hudson (eruption units H1 and H2), Aguilera (A1), Reclus (R1, R2-3), Mt Burney (MB1, MB2, MBx, MB1910) and historical Lautaro/Viedma deposits. The analysis of the ninety-four tephra layers observed in the Laguna Potrok Aike sedimentary sequence reveals that twenty-five tephra deposits in the record are the result of primary fallout and are sourced from at least three different volcanoes in the Austral Andean Volcanic Zone (Mt Burney, Reclus, Lautaro/Viedma) and one in the southernmost Southern Volcanic Zone (Hudson). One new correlation to the widespread H1 eruption from Hudson volcano at 8.7 (8.6–9.0) cal ka BP during the Quaternary is identified. The identification of sixty-five discrete deposits that were predominantly volcanic ashes (glass and minerals) with subtle characteristics of reworking (in addition to three likely reworked tephra, and one unknown layer) indicates that care must be taken in the analysis of both visible and invisible tephra layers to decipher their emplacement mechanisms. © 2019 The Authors
2303.
Practice of Turbo-drill core drilling in Well SK-2
Drilling & Production Technology,
42
(1)
31-34
2019
2302.
Paleoenvironmental and paleoclimatic variations around Lake Van (Eastern Turkey) recorded by sedimentary source specific biomarkers 250–130 ka (MIS7 and MIS6)
Quaternary Science Reviews,
225
2019
2301.
Pollen-based temperature and precipitation changes in the Ohrid Basin (western Balkans) between 160 and 70 ka
Climate of the Past,
15
(1)
53-71
2019
ISSN: 18149324
Publisher: Copernicus GmbH
Keywords:▾
climate variation; Eemian; marine isotope stage; paleoclimate; pollen; precipitation (climatology); temperature, Atlantic Ocean; Atlantic Ocean (North); Balkans; Lake Ohrid; Southern Europe
Abstract: ▾ Our study aims to reconstruct climate changes that occurred at Lake Ohrid (south-western Balkan Peninsula), the oldest extant lake in Europe, between 160 and 70 ka (covering part of marine isotope stage 6, MIS 6; all of MIS 5; and the beginning of MIS 4). A multi-method approach, including the "Modern Analog Technique" and the "Weighted Averaging Partial Least-Squares Regression", is applied to the high-resolution pollen sequence of the DEEP site, collected from the central part of Lake Ohrid, to provide quantitative estimates of climate and bioclimate parameters. This allows us to document climatic change during the key periods of MIS 6 and MIS 5 in southern Europe, a region where accurate climate reconstructions are still lacking for this time interval.</p> Our results for the penultimate glacial show cold and dry conditions, while the onset of the "last interglacial" is characterized by wet and warm conditions, with temperatures higher than today (by ca. 2 <span classCombining double low line"inline-formula">ĝ</span>C). The Eemian also shows the well-known climatic tri-partition in the Balkans, with an initial pre-temperate phase of abrupt warming (128-121 ka), a central temperate phase with decreasing temperatures associated with wet conditions (121-118 ka), followed by a post-temperate phase of progressive change towards cold and dry conditions (118-112 ka).</p> After the Eemian, an alternation of four warm/wet periods with cold/dry ones, likely related to the succession of Greenland stadials and cold events known from the North Atlantic, occurred. The observed pattern is also consistent with hydrological and isotopic data from the central Mediterranean.</p> The Lake Ohrid climate reconstruction shows greater similarity with climate patterns inferred from northern European pollen records than with southern European ones, which is probably due to its intermediate position and the mountainous setting. However, this hypothesis needs further testing as very few climate reconstructions are available for southern Europe for this key time period.</p>. © Author(s) 2019.
2300.
Organic-rich source rock characterization and evaluation of the Cretaceous Qingshankou Formation: results from geophysical logs of the second scientific drilling borehole in the Songliao Basin, NE China
Geosciences Journal,
23
(1)
119-135
2019
ISSN: 12264806
Publisher: Korean Association of Geoscience Societies
Abstract: ▾ The second continental scientific drilling (SKII east) borehole in the Songliao Basin has been planned to be the deepest borehole to drill through the Cretaceous continental strata under the framework of the International Continental Scientific Drilling Program (ICDP) up to date. This borehole was designed not only to explore the potential relationships between dinosaur extinction and climate environment during the Cretaceous but also to achieve new breakthroughs in oil and gas exploration. The high hydrocarbon (oil and gas) potential of a source rock is highly dependent on its organic content. We used geophysical log data of Borehole SKII east to evaluate the organic content of organic-rich source rock. In the period of the first member in the Qingshankou Formation (K2qn1) from the study area, high accommodation space and anoxic environment could promote organic matter deposition. Firstly, based on geological information and abundant geophysical log data, the basic geophysical characteristics (including petrophysical, lithological, mineralogical, and sedimentary properties) of the Qingshankou Formation in Borehole SKII east were studied. Secondly, geophysical log response characteristics (including resistivity, porosity, radioactivity, mineral and element) of organic-rich source rocks were analyzed. Thirdly, we tried to obtain suitable methods to predict total organic carbon (TOC) content of the target formation with geophysical log data. The laboratorymeasured TOC values of core samples from Borehole SKI south were used to make calibrations with calculated TOC values from geophysical logs. Results from improved ΔlogR technique and Dual_Vsh method are consistent, and indicate that these two methods are effective in this formation. The calculated TOC values from these two methods are relatively desirable, and show that the organic-rich source rocks with high TOC content occurred in the K2qn1 (1646.00~1669.00 m). The highest TOC content can reach 9.15%. The bed thicknesses of organic-rich source rocks are totally up to 7.88 m. These organic-rich source rocks can be considered as excellent. This study demonstrated that improve ΔlogR technique can be applied to evaluate source rocks in the formations without maturity data, and the new method Dual_Vsh is also valid in the Qingshankou Formation. The organic-rich source rock evaluation results could promote further exploration and development of oil and gas resources in the upper Cretaceous formations, Songliao Basin. © 2019, The Association of Korean Geoscience Societies and Springer-Verlag GmbH Germany, part of Springer Nature.
2299.
Rock-magnetic and paleomagnetic studies on late-Holocene sediments from Laguna Cháltel (Patagonia, Argentina)
Journal of South American Earth Sciences,
90204 – 215
2019
2298.
Northeast Atlantic breakup volcanism and consequences for Paleogene climate change-MagellanPlus Workshop report
Scientific Drilling,
2669-85
2019
ISSN: 18168957
Publisher: Copernicus GmbH
Keywords:▾
Geodynamics; Infill drilling; Volcanoes, Geodynamic models; Long-term interaction; North East Atlantic; Northeast Atlantic Ocean; Ocean drilling programs; Oceanographic circulation; Paleogene climate; Vertical movement, Climate change
Abstract: ▾ The northeast Atlantic encompasses archetypal examples of volcanic rifted margins. Twenty-five years after the last ODP (Ocean Drilling Program) leg on these volcanic margins, the reasons for excess melting are still disputed with at least three competing hypotheses being discussed. We are proposing a new drilling campaign that will constrain the timing, rates of volcanism, and vertical movements of rifted margins. This will allow us to parameterise geodynamic models that can distinguish between the hypotheses. Furthermore, the drilling-derived data will help us to understand the role of breakup magmatism as a potential driver for the Palaeocene-Eocene thermal maximum (PETM) and its influence on the oceanographic circulation in the earliest phase of the northeast Atlantic Ocean formation. Tackling these questions with a new drilling campaign in the northeast Atlantic region will advance our understanding of the long-term interactions between tectonics, volcanism, oceanography, and climate and the functioning of subpolar northern ecosystems and climate during intervals of extreme warmth. © Author(s) 2019.
2297.
Occurrence of clastic injectites in the oligocene strata of the carpathians and their significance in unravelling the paleogene and neogene evolution of the Carpathian orogeny (Poland, Ukraine and Romania)
Geological Quarterly,
63
(1)
106-125
2019
DOI:10.7306/gq.1460
Abstract: ▾ The irregular distribution of sand injections, traditionally termed “dykes" in the Polish geological literature, within individual Carpathian units and within individual lithofacies were observed during long-lasting field works. Injectites have been observed in the Magura Beds and in the Inoceramian Beds of the Polish and Romanian Carpathians, and in the Central Carpathian Paleogene deposits. However, they are most common in the Oligocene-Miocene Menilite Beds, where they are typical and abundant, particularly in the Skole Unit. Two clastic injectite types were distinguished: sedimentary (S-type) and tectonized (T-type). Based on the occurrence and interpretation of these injectites a new two-stage conceptual model is proposed for the Polish segment of the progressive Oligocene-Miocene Carpathian orogenic belt evolution. Type S clastic injectites are interpreted as having formed in the compressional stage, during foredeep basin migration while depositional slope changes were taking place in the Late Oligocene to Early Miocene. Type T injectites are interpreted as having formed by reactivation of S-type injectites in the last, mainly strike-slip, phases of Carpathian orogenic belt formation. © 2019, Polish Geological Institute. All rights reserved.
2296.
Ocean drilling perspectives on meteorite impacts
Oceanography,
32
(1)
120-134
2019
Abstract: ▾ Extraterrestrial impacts that reshape the surfaces of rocky bodies are ubiquitous in the solar system. On early Earth, impact structures may have nurtured the evolution of life. More recently, a large meteorite impact off the Yucatán Peninsula in Mexico at the end of the Cretaceous caused the disappearance of 75% of species known from the fossil record, including non-avian dinosaurs, and cleared the way for the dominance of mammals and the eventual evolution of humans. Understanding the fundamental processes associated with impact events is critical to understanding the history of life on Earth, and the potential for life in our solar system and beyond. Scientific ocean drilling has generated a large amount of unique data on impact processes. In particular, the Yucatán Chicxulub impact is the single largest and most significant impact event that can be studied by sampling in modern ocean basins, and marine sediment cores have been instrumental in quantifying its environmental, climatological, and biological effects. Drilling in the Chicxulub crater has significantly advanced our understanding of fundamental impact processes, notably the formation of peak rings in large impact craters, but these data have also raised new questions to be addressed with future drilling. Within the Chicxulub crater, the nature and thickness of the melt sheet in the central basin is unknown, and an expanded Paleocene hemipelagic section would provide insights to both the recovery of life and the climatic changes that followed the impact. Globally, new cores collected from today’s central Pacific could directly sample the downrange ejecta of this northeast-southwest trending impact. Extraterrestrial impacts have been controversially suggested as primary drivers for many important paleoclimatic and environmental events throughout Earth history. However, marine sediment archives collected via scientific ocean drilling and geochemical proxies (e.g., osmium isotopes) provide a long-term archive of major impact events in recent Earth history and show that, other than the end-Cretaceous, impacts do not appear to drive significant environmental changes. © 2019 The Oceanography Society, Inc.
2295.
On the mophology, measurement and description of Triprojectacites (in Chinese with English abstract);[三突起类花粉形态学及其度量和描述]
Acta Palaeontologica Sinica,
58
(2)
232-248
2019