Search

Your search keyword '"Whalen, Michael T."' showing total 103 results
Start Over Author "Whalen, Michael T."
103 results on '"Whalen, Michael T."'

3. The first day of the Cenozoic

Author

Expedition 364 Scientists, Gulick, Sean P. S., Bralower, Timothy J., Ormö, Jens, Hall, Brendon, Grice, Kliti, Schaefer, Bettina, Lyons, Shelby, Freeman, Katherine H., Morgan, Joanna V., Artemieva, Natalia, Kaskes, Pim, de Graaff, Sietze J., Whalen, Michael T., Collins, Gareth S., Tikoo, Sonia M., Verhagen, Christina, Christeson, Gail L., Claeys, Philippe, Coolen, Marco J. L., Goderis, Steven, Goto, Kazuhisa, Grieve, Richard A. F., McCall, Naoma, Osinski, Gordon R., Rae, Auriol S. P., Riller, Ulrich, Smit, Jan, Vajda, Vivi, and Wittmann, Axel

Published
2019

4. Late inception of a resiliently oxygenated upper ocean

Author

Lu, Wanyi, Ridgwell, Andy, Thomas, Ellen, Hardisty, Dalton S., Luo, Genming, Algeo, Thomas J., Saltzman, Matthew R., Gill, Benjamin C., Shen, Yanan, Ling, Hong-Fei, Edwards, Cole T., Whalen, Michael T., Zhou, Xiaoli, Gutchess, Kristina M., Jin, Li, Rickaby, Rosalind E. M., Jenkyns, Hugh C., Lyons, Timothy W., Lenton, Timothy M., Kump, Lee R., and Lu, Zunli

Published
2018

5. Rapid recovery of life at ground zero of the end-Cretaceous mass extinction

Author

Lowery, Christopher M., Bralower, Timothy J., Owens, Jeremy D., Rodríguez-Tovar, Francisco J., Jones, Heather, Smit, Jan, Whalen, Michael T., Claeys, Phillipe, Farley, Kenneth, Gulick, Sean P. S., Morgan, Joanna V., Green, Sophie, Chenot, Elise, Christeson, Gail L., Cockell, Charles S., Coolen, Marco J. L., Ferrière, Ludovic, Gebhardt, Catalina, Goto, Kazuhisa, Kring, David A., Lofi, Johanna, Ocampo-Torres, Rubén, Perez-Cruz, Ligia, Pickersgill, Annemarie E., Poelchau, Michael H., Rae, Auriol S. P., Rasmussen, Cornelia, Rebolledo-Vieyra, Mario, Riller, Ulrich, Sato, Honami, Tikoo, Sonia M., Tomioka, Naotaka, Urrutia-Fucugauchi, Jaime, Vellekoop, Johan, Wittmann, Axel, Xiao, Long, Yamaguchi, Kosei E., and Zylberman, William

Published
2018
Full Text
View/download PDF

9. Cretaceous Extinctions: Evidence Overlooked [with Response]

Author

KELLER, GERTA, ADATTE, THIERRY, PARDO, ALFONSO, BAJPAI, SUNIL, KHOSLA, ASHU, SAMANT, BANDANA, SCHULTE, PETER, ALEGRET, LAIA, ARENILLAS, IGNACIO, ARZ, JOSÉ A., BARTON, PENNY J., BOWN, PAUL R., BRALOWER, TIMOTHY J., CHRISTESON, GAIL L., CLAEYS, PHILIPPE, COCKELL, CHARLES S., COLLINS, GARETH S., DEUTSCH, ALEXANDER, GOLDIN, TAMARA J., GOTO, KAZUHISA, GRAJALES-NISHIMURA, JOSÉ M., GRIEVE, RICHARD A. F., GULICK, SEAN P. S., JOHNSON, KIRK R., KIESSLING, WOLFGANG, KOEBERL, CHRISTIAN, KRING, DAVID A., MACLEOD, KENNETH G., MATSUI, TAKAFUMI, MELOSH, JAY, MONTANARI, ALESSANDRO, MORGAN, JOANNA V., NEAL, CUVE R., NORRIS, RICHARD D., PIERAZZO, ELISABETTA, RAVIZZA, GREG, REBOLLEDO-VIEYRA, MARIO, REIMOLD, WOLF UWE, ROBIN, ERIC, SALGE, TOBIAS, SPEIJER, ROBERT P., SWEET, ARTHUR R., URRUTIA-FUCUGAUCHI, JAIME, VAJDA, VIVI, WHALEN, MICHAEL T., and WILLUMSEN, PI S.

Published
2010

10. The Chicxulub Asteroid Impact and Mass Extinction at the Cretaceous-Paleogene Boundary

Author

Schulte, Peter, Alegret, Laia, Arenillas, Ignacio, Arz, José A., Barton, Penny J., Bown, Paul R., Bralower, Timothy J., Christeson, Gail L., Claeys, Philippe, Cockell, Charles S., Collins, Gareth S., Deutsch, Alexander, Goldin, Tamara J., Goto, Kazuhisa, Grajales-Nishimura, José M., Grieve, Richard Á. F., Gulick, Sean P. S., Johnson, Kirk R., Kiessling, Wolfgang, Koeberl, Christian, Kring, David A., MacLeod, Kenneth G., Matsui, Takafumi, Melosh, Jay, Montanari, Alessandro, Morgan, Joanna V., Neal, Clive R., Nichols, Douglas J., Norris, Richard D., Pierazzo, Elisabetta, Ravizza, Greg, Rebolledo-Vieyra, Mario, Reimold, Wolf Uwe, Robin, Eric, Salge, Tobias, Speijer, Robert P., Sweet, Arthur R., Urrutia-Fucugauchi, Jaime, Vajda, Vivi, Whalen, Michael T., and Willumsen, Pi S.

Published
2010
Full Text
View/download PDF

11. Shock-deformed zircon from the Chicxulub impact crater and implications for cratering process

Author

Zhao, Jiawei, Xiao, Long, Xiao, Zhiyong, Morgan, Joanna, Osinski, Gordon, Neal, Clive, Gulick, Sean P.S., Riller, Ulrich, Claeys, Philippe, Zhao, Shanrong, Prieur, Nils, Nemchin, Alexander, Yu, Shuoran, Chenot, Elise, Christeson, Gail l., Cockell, Charles S., Coolen, Marco J.L., Ferrière, Ludovic, Gebhardt, Catalina, Goto, Kazuhisa, Jones, Heather, Kring, David A., LOFI, Johanna, Lowery, Christopher M., OCAMPO-TORRES, Ruben, Perez-Cruz, Ligia, Pickersgill, Annemarie E., Poelchau, Michael H., Rasmussen, Cornelia, Rebolledo-Vieyra, Mario, Sato, Honami, Smit, Jan, Tikoo-Schantz, Sonia M., Tomioka, Naotaka, Urrutia Fucugauchi, Jaime, Whalen, Michael T., Wittmann, Axel, Yamaguchi, Kosei E., Institut de chimie et procédés pour l'énergie, l'environnement et la santé (ICPEES), Université de Strasbourg (UNISTRA)-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Natural Environment Research Council (NERC), Analytical, Environmental & Geo-Chemistry, Earth System Sciences, and Chemistry

Subjects
Geochemistry & Geophysics, Reidite, 010504 meteorology & atmospheric sciences, 04 Earth Sciences, Geology, zircon, 010502 geochemistry & geophysics, 01 natural sciences, Shock (mechanics), Shock metamorphism, Impact crater, 13. Climate action, [SDU]Sciences of the Universe [physics], Scientific method, microstructures, shock metamorphism, Petrology, Cratering, 0105 earth and related environmental sciences, Zircon
Abstract

International audience; Large impact structures with peak rings are common landforms across the solar system, and their formation has implications for both the interior structure and thermal evolution of planetary bodies. Numerical modeling and structural studies have been used to simulate and ground truth peak-ring formative mechanisms, but the shock metamorphic record of minerals within these structures remains to be ascertained. We investigated impact-related microstructures and high-pressure phases in zircon from melt-bearing breccias, impact melt rock, and granitoid basement from the Chicxulub peak ring (Yucatán Peninsula, Mexico), sampled by the International Ocean Discovery Program (IODP)/International Continental Drilling Project (IODP-ICDP) Expedition 364 Hole M0077A. Zircon grains exhibit shock features such as reidite, zircon twins, and granular zircon including “former reidite in granular neoblastic” (FRIGN) zircon. These features record an initial high-pressure shock wave (>30 GPa), subsequent relaxation during the passage of the rarefaction wave, and a final heating and annealing stage. Our observed grain-scale deformation history agrees well with the stress fields predicted by the dynamic collapse model, as the central uplift collapsed downward-then-outward to form the peak ring. The occurrence of reidite in a large impact basin on Earth represents the first such discovery, preserved due to its separation from impact melt and rapid cooling by the resurging ocean. The coexistence of reidite and FRIGN zircon within the impact melt–bearing breccias indicates that cooling by seawater was heterogeneous. Our results provide valuable information on when different shock microstructures form and how they are modified according to their position in the impact structure, and this study further improves on the use of shock barometry as a diagnostic tool in understanding the cratering process.

Published
2021

17. Geochemistry, geochronology and petrogenesis of Maya Block granitoids and dikes from the Chicxulub Impact Crater, Gulf of México: Implications for the assembly of Pangea

Author

Zhao, Jiawei, Xiao, Long, Gulick, Sean P.S., Morgan, Joanna, Kring, David, Fucugauchi, Jaime Urrutia, Schmieder, Martin, de Graaff, Sietze, Wittmann, Axel, ROSS, Catherine, Claeys, Philippe, Pickersgill, Annemarie, Kaskes, Pim, Goderis, Steven, Rasmussen, Cornelia, Vajda, Vivi, Ferrière, Ludovic, Feignon, Jean–Guillaume, Chenot, Elise, Sato, Honami, Yamaguchi, Kosei, J. Bralower, Timothy, Christeson, Gail l., Cockell, Charles S., Coolen, Marco J.L., Gebhardt, Catalina, Goto, Kazuhisa, Green, Sophie, Jones, Heather, LeBer, Erwan, LOFI, Johanna, Lowery, Christopher, OCAMPO-TORRES, Ruben, Perez-Cruz, Ligia, Poelchau, Michael H., Rae, Auriol S.P., Rebolledo-Vieyra, Mario, Riller, Ulrich, Smit, Jan, Tikoo-Schantz, Sonia M., Tomioka, Naotaka, Whalen, Michael T., Chemistry, Analytical, Environmental & Geo-Chemistry, Faculty of Sciences and Bioengineering Sciences, Earth System Sciences, Institut de chimie et procédés pour l'énergie, l'environnement et la santé (ICPEES), Université de Strasbourg (UNISTRA)-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), State Key Laboratory of Geological Processes and Mineral Resources [Wuhan] (GPMR), China University of Geosciences [Wuhan] (CUG), State Key Laboratory of Lunar and Planetary Sciences, Macau University of Science and Technology (MUST), Institute of Geophysics [Austin] (IG), University of Texas at Austin [Austin], Department of Earth Science and Engineering [Imperial College London], Imperial College London, Lunar and Planetary Institute [Houston] (LPI), Instituto de Geofisica [Mexico], Universidad Nacional Autónoma de México (UNAM), Analytical, Environmental and Geo- Chemistry, Vrije Universiteit Brussel (VUB), Arizona State University [Tempe] (ASU), Eyring Materials Center for Solid State Science, School of Geographical and Earth Sciences [Univ Glasgow], University of Glasgow, NERC Argon Isotope Facility [Glasgow], Scottish Universities Environmental Research Centre (SUERC), University of Glasgow-University of Edinburgh-University of Glasgow-University of Edinburgh-Natural Environment Research Council (NERC), Department of Geology and Geophysics, University of Utah, Department of Palaeobiology [Stockholm], Swedish Museum of Natural History (NRM), Natural History Museum [Vienna] (NHM), Department of Lithospheric Research [Wien], Universität Wien, Biogéosciences [UMR 6282] [Dijon] (BGS), Université de Bourgogne (UB)-AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement-Centre National de la Recherche Scientifique (CNRS), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Department of Chemistry, Toho University, and Study funded by the National Natural Science Foundation of China (41772050, 41830214, 41773061), MOST Special Fund from the State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences (MSFGPMR05) and the Science andTechnology Development Fund (FDCT) of Macau (Grant No. 121/2017/A3).

Subjects
Felsite, 010504 meteorology & atmospheric sciences, Geochemistry, [SDU.STU.PE]Sciences of the Universe [physics]/Earth Sciences/Petrography, Annan geovetenskap och miljövetenskap, Geology, Orogeny, Pangea, 010502 geochemistry & geophysics, Anatexis, 01 natural sciences, Continental arc, Peri–Gondwanan realm, Gondwana, [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry, [SDU]Sciences of the Universe [physics], Geochronology, Chicxulub impact crater, Slab breakoff, Laurentia, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Petrogenesis, Other Earth and Related Environmental Sciences
Abstract

23 pages; International audience; The Late Paleozoic tectono–magmatic history and basement of the Maya block are poorly understood due to the lack of exposures of coeval magmatic rocks in the region. Recently, IODP–ICDP Expedition 364 recovered drill core samples at borehole M0077A from the peak ring of the Chicxulub impact crater, offshore of the Yucatán peninsula in the Gulf of México, have been studied comprehensively. In the lowermost ~600 m of the drill core, impact–deformed granitoids, and minor felsite and dolerite dykes are intercalated with impact melts and breccias. Zircon U-Pb dating of granitoids yielded ages of around 326 ± 5 Ma, representing the first recovery of Late Paleozoic magmatic rocks from the Maya block, which could be genetically related to the convergence of Laurentia and Gondwana. The granitoids show the features of high K2O/Na2O, LaN/YbN and Sr/Y ratios, but very low Yb and Y contents, indicating an adakitic affinity. They are also characterized by slightly positive ԑNd(326Ma) of 0.17–0.68, intermediate initial 87Sr/86Sr(326Ma) of 0.7036–0.7047 and two–stage Nd model age (TDM2) of 1027–1069 Ma, which may indicate a less evolved crustal source. Thus, the adakitic granitoids were probably generated by partial melting of thickened crust, with source components similar to Neoproterozoic metagabbro in the Carolina block (Pan–African Orogeny materials) along Peri–Gondwana. Felsite dykes are shoshonitic with typical continental arc features that are sourced from a metasomatic mantle wedge by slab–fluids. Dolerite dykes display OIB–type features such as positive Nb and Ta anomalies and low ThNpm/NbNpm. In our interpretation, the Chicxulub adakitic granitoids of this study are formed by crustal anatexis due to asthenospheric upwelling resulting from slab breakoff. Through comparing sources and processes of Late Paleozoic magmatism along the Peri–Gondwanan realm, a tearing slab breakoff model may explain the discontinuous magmatism that appears to have occurred during the convergence of Laurentia and Gondwana.

Published
2020

21. Probing the hydrothermal system of the Chicxulub impact crater

Author

Kring, David A., primary, Tikoo, Sonia M., additional, Schmieder, Martin, additional, Riller, Ulrich, additional, Rebolledo-Vieyra, Mario, additional, Simpson, Sarah L., additional, Osinski, Gordon R., additional, Gattacceca, Jérôme, additional, Wittmann, Axel, additional, Verhagen, Christina M., additional, Cockell, Charles S., additional, Coolen, Marco J. L., additional, Longstaffe, Fred J., additional, Gulick, Sean P. S., additional, Morgan, Joanna V., additional, Bralower, Timothy J., additional, Chenot, Elise, additional, Christeson, Gail L., additional, Claeys, Philippe, additional, Ferrière, Ludovic, additional, Gebhardt, Catalina, additional, Goto, Kazuhisa, additional, Green, Sophie L., additional, Jones, Heather, additional, Lofi, Johanna, additional, Lowery, Christopher M., additional, Ocampo-Torres, Rubén, additional, Perez-Cruz, Ligia, additional, Pickersgill, Annemarie E., additional, Poelchau, Michael H., additional, Rae, Auriol S. P., additional, Rasmussen, Cornelia, additional, Sato, Honami, additional, Smit, Jan, additional, Tomioka, Naotaka, additional, Urrutia-Fucugauchi, Jaime, additional, Whalen, Michael T., additional, Xiao, Long, additional, and Yamaguchi, Kosei E., additional

Published
2020
Full Text
View/download PDF

22. Microbial life in the nascent Chicxulub crater

Author

Schaefer, Bettina, primary, Grice, Kliti, primary, Coolen, Marco J.L., primary, Summons, Roger E., primary, Cui, Xingqian, primary, Bauersachs, Thorsten, primary, Schwark, Lorenz, primary, Böttcher, Michael E., primary, Bralower, Timothy J., primary, Lyons, Shelby L., primary, Freeman, Katherine H., primary, Cockell, Charles S., primary, Gulick, Sean P.S., primary, Morgan, Joanna V., primary, Whalen, Michael T., primary, Lowery, Christopher M., primary, and Vajda, Vivi, primary

Published
2020
Full Text
View/download PDF

23. Early Paleocene Paleoceanography and Export Productivity in the Chicxulub Crater.

Author

Lowery, Christopher M., Jones, Heather L., Bralower, Timothy J., Cruz, Ligia Perez, Gebhardt, Catalina, Whalen, Michael T., Chenot, Elise, Smit, Jan, Phillips, Marcie Purkey, Choumiline, Konstantin, Arenillas, Ignacio, Arz, Jose A., Garcia, Fabien, Ferrand, Myriam, and Gulick, Sean P. S.

Subjects
PALEOCENE Epoch, PALEOCEANOGRAPHY, EUPHOTIC zone, CARBON isotopes, MASS extinctions, PALEOGENE, CALCAREOUS soils
Abstract

The Chicxulub impact caused a crash in productivity in the world's oceans which contributed to the extinction of ∼75% of marine species. In the immediate aftermath of the extinction, export productivity was locally highly variable, with some sites, including the Chicxulub crater, recording elevated export production. The long‐term transition back to more stable export productivity regimes has been poorly documented. Here, we present elemental abundances, foraminifer and calcareous nannoplankton assemblage counts, total organic carbon, and bulk carbonate carbon isotope data from the Chicxulub crater to reconstruct changes in export productivity during the first 3 Myr of the Paleocene. We show that export production was elevated for the first 320 kyr of the Paleocene, declined from 320 kyr to 1.2 Myr, and then remained low thereafter. A key interval in this long decline occurred 900 kyr to 1.2 Myr post impact, as calcareous nannoplankton assemblages began to diversify. This interval is associated with fluctuations in water column stratification and terrigenous flux, but these variables are uncorrelated to export productivity. Instead, we postulate that the turnover in the phytoplankton community from a post‐extinction assemblage dominated by picoplankton (which promoted nutrient recycling in the euphotic zone) to a Paleocene pelagic community dominated by relatively larger primary producers like calcareous nannoplankton (which more efficiently removed nutrients from surface waters, leading to oligotrophy) is responsible for the decline in export production in the southern Gulf of Mexico. Plain Language Summary: The end Cretaceous mass extinction was caused by the impact of an asteroid in what is now the Yucatán Peninsula, México. The impact ejected aerosols and dust into the air that reduced sunlight transmission, causing a severe decline in photosynthesis and the collapse of marine food webs. However, the change in the amount of organic matter created by photosynthesizing plankton that was delivered to the seafloor (export productivity) was variable across the oceans. At some places, including the Chicxulub crater, export productivity was actually high immediately after the impact. We produced a ∼3‐million ‐year record of export productivity in the crater to determine how long it remained elevated and why it eventually declined. Export production was very high for the first 320,000 years after the impact, declined from 320,000 to 1,200,000 years after the impact, and then remained low. We found that this production was not related to the input of nutrients nor the degree of stratification of the ocean, but instead was probably driven by the increase in the cell size of phytoplankton. Larger phytoplankton removed nutrients from the surface waters as they sank, prompting an increase in species which are better adapted to low‐nutrient waters. Key Points: Export productivity at Chicxulub was elevated for 1.2 Myr post K‐Pg; it was very high for the first 0.32 Myr and declined from 0.32–1.2 MyrThe final decline in export productivity ∼0.9–1.2 Myr is associated with the termination of calcareous nannoplankton disaster assemblagesExport productivity change is not correlated with stratification or terrigenous input and was likely driven by changes in the phytoplankton [ABSTRACT FROM AUTHOR]

Published
2021
Full Text
View/download PDF

24. Impact-induced porosity and micro-fracturing at the Chicxulub impact structure

Author

Rae, Auriol, Collins, Gareth, Morgan, Joanna, Salge, Tobias, Christeson, Gail, Leung, Jody, Lofi, Johanna, Gulick, Sean, Poelchau, Michael, Riller, Ulrich, Gebhardt, Catalina, Grieve, Richard, Osinski, Gordon, Chenot, Elise, Claeys, Philippe, Cockell, Charles S., Coolen, Marco J.L., Ferrière, Ludovic, Goto, Kazuhisa, Green, Sophie, Jones, Heather, Kring, David A., Lowery, Christopher, IODP-ICDP Expedition 364 scientists,, Perez-Cruz, Ligia, Pickersgill, Annemarie E., Rasmussen, Cornelia, Rebolledo-Vieyra, Mario, Sato, Honami, Smit, Jan, Tikoo-Schantz, Sonia M., Tomioka, Naotaka, Urrutia-Fucugauchi, Jaime, Whalen, Michael T., Wittmann, Axel, Xiao, Long, Yamaguchi, Kosei E., Science and Technology Facilities Council (STFC), Natural Environment Research Council (NERC), Department of Earth Science and Engineering [Imperial College London], Imperial College London, The Natural History Museum [London] (NHM), University of Texas at Austin [Austin], Géosciences Montpellier, Institut national des sciences de l'Univers (INSU - CNRS)-Université de Montpellier (UM)-Université des Antilles (UA)-Centre National de la Recherche Scientifique (CNRS), Albert-Ludwigs-Universität Freiburg, Universität Hamburg (UHH), Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung (AWI), University of Western Ontario (UWO), Mémoires - Université de Montpellier - Faculté des sciences (UM FS), and Université de Montpellier (UM)

Subjects
Geochemistry & Geophysics, porosity, 010504 meteorology & atmospheric sciences, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], 01 natural sciences, Gravity anomaly, Seismic wave, Impact crater, GRAVITY, Geochemistry and Petrology, DEFORMATION, CRATER, Earth and Planetary Sciences (miscellaneous), Impact structure, Petrology, Magnetic anomaly, CRUSTAL STRUCTURE, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Science & Technology, ORIGIN, Scientific drilling, Petrophysics, cratering, YUCATAN, International Ocean Discovery Program, fractures, Geophysics, Chicxulub, SIZE, PEAK-RING FORMATION, [SDU]Sciences of the Universe [physics], 13. Climate action, Space and Planetary Science, Physical Sciences, ASYMMETRY, Geology, HYDROCODE SIMULATIONS
Abstract

International audience; Porosity and its distribution in impact craters has an important effect on the petrophysical properties of impactites: seismic wave speeds and reflectivity, rock permeability, strength, and density. These properties are important for the identification of potential craters and the understanding of the process and consequences of cratering. The Chicxulub impact structure, recently drilled by the joint International Ocean Discovery Program and International Continental scientific Drilling Program Expedition 364, provides a unique opportunity to compare direct observations of impactites with geophysical observations and models. Here, we combine small-scale petrographic and petrophysical measurements with larger-scale geophysical measurements and numerical simulations of the Chicxulub impact structure. Our aim is to assess the cause of unusually high porosities within the Chicxulub peak ring and the capability of numerical impact simulations to predict the gravity signature and the distribution and texture of porosity within craters. We show that high porosities within the Chicxulub peak ring are primarily caused by shock-induced microfracturing. These fractures have preferred orientations, which can be predicted by considering the orientations of principal stresses during shock, and subsequent deformation during peak ring formation. Our results demonstrate that numerical impact simulations, implementing the Dynamic Collapse Model of peak ring formation, can accurately predict the distribution and orientation of impact-induced microfractures in large craters, which plays an important role in the geophysical signature of impact structures. Plain Language Summary The Chicxulub crater, Mexico, is widely known for its association with the extinction of the nonavian dinosaurs at the end of the Cretaceous period. The crater was first identified due to its gravitational and magnetic anomalies. Potential impact structures are often identified, in part, on the basis of geophysical anomalies, most commonly including a circular gravity low. Gravity is slightly weaker at craters because the impact cratering process removes mass from the impact site. In this study, we examine the cause of the Chicxulub gravity anomaly by combining observations from recent drilling of the crater, geophysical data measured across the crater, and numerical impact simulations. We demonstrate that porosity in rocks beneath the crater floor is primarily accommodated by fracturing during the impact cratering process, that the orientation of those fractures are consistent with predictions from numerical impact simulations, and that impact-induced porosity is one of the primary causes of gravity anomalies in large impact craters.

Published
2019

25. U-Pb memory behavior in Chicxulub's peak ring — Applying U-Pb depth profiling to shocked zircon

Author

Rasmussen, Cornelia, Stockli, Daniel, Ross, Catherine, Pickersgill, Annemarie, Gulick, Sean, Schmieder, Martin, Christeson, Gail, Wittmann, Axel, Kring, David, Morgan, Joanna, J. Bralower, Timothy, Claeys, Philippe, Cockell, Charles S., Coolen, Marco J.L., Ferrière, Ludovic, Gebhardt, Catalina, Goto, Kazuhisa, Green, Sophie, Jones, Heather, LeBer, Erwan, LOFI, Johanna, Lowery, Christopher M., OCAMPO-TORRES, Ruben, Perez-Cruz, Ligia, Poelchau, Michael H., Rae, Auriol S.P., Rebolledo-Vieyra, Mario, Riller, Ulrich, Sato, Honami, Smit, Jan, Tikoo-Schantz, Sonia M., Tomioka, Naotaka, Urrutia-Fucugauchi, Jaimie, Whalen, Michael T., Long, Xiao, Yamaguchi, Kosei E., Jackson School of Geosciences (JSG), University of Texas at Austin [Austin], School of Geographical and Earth Sciences [Univ Glasgow], University of Glasgow, Institut de chimie et procédés pour l'énergie, l'environnement et la santé (ICPEES), Université de Strasbourg (UNISTRA)-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), and Natural Environment Research Council (NERC)

Subjects
Geochemistry & Geophysics, 010504 meteorology & atmospheric sciences, Geochemistry, SYSTEMATICS, 010502 geochemistry & geophysics, 01 natural sciences, Hydrothermal circulation, Metamictization, IODP, LEAD, Shock metamorphism, AGE, Impact crater, Geochemistry and Petrology, [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry, 0402 Geochemistry, Impact structure, MELT, 0105 earth and related environmental sciences, Science & Technology, GEOCHRONOLOGY, Geology, IMPACT CRATER, MONAZITE, RADIATION-DAMAGE, Chicxulub, EVENT, 0403 Geology, 13. Climate action, U-Pb systematics, Monazite, Physical Sciences, Geochronology, 0406 Physical Geography and Environmental Geoscience, LA-ICP-MS depth profiling, Zircon
Abstract

International audience; The zircon U-Pb system is one of the most robust geochronometers, but during an impact event individual crystals can be affected differently by the passage of the shock wave and impact generated heat. Unraveling the potentially complex thermal history recorded by zircon crystals that experienced variable levels of shock and heating, as well as additioanl pre-and post-impact thermal events, has been difficult using classical geochronological methods. The existing high-precision 40 Ar/ 39 Ar age constraints for the K-Pg Chicxulub event, and the previous U-Pb dating of the basement rocks from the impact site, make Chicxulub an ideal location to study impact-induced effects on the zircon U-Pb systematics and to evaluate potential 'memory effects' of pre-impact U-Pb signatures preserved within those individual zircon crystals. Recent IODP-ICDP drilling of the Chicxulub impact structure recovered 580 m of uplifted shocked granitoid and 130 m of melt and suevite, providing an unprecedented opportunity to study zircon crystals subjected to a range of shock pressures, thermal, and deformational histories. Zircon morphologies were classified using scanning electron microscopy (SEM) imaging and then samples were depth profiled using laser ablation inductively coupled plasma mass-spectrometry (LA-ICP-MS) to document the range of preserved age domains from rim-to-center within individual crystals. The results show U-Pb ages range from 66 to 472 Ma, which are consistent with both inherited Carboniferous and Late Paleozoic basement ages as well as Pb loss ages in response to the K-Pg impact event. While the bulk of the zircon grains preserve Paleozoic ages, high U (metamict) zones within fractured zircon crystals exhibited an age within uncertainty (66 ± 6.2 Ma) of the impact age (66.038 ± 0.049 Ma), indicating that inherited intragrain U-Pb kinetics and/or hydrothermal fluid flow may have controlled age resetting those zircon crystals rather than impact-induced shock and heating alone. Moreover, the calculated α-decay doses suggest that the zircon crystals experienced Stage 1 or early Stage 2 radiation damage accumulation. Therefore, we suggest that the lowered crystal annealing temperature in crystals that previoulsy experienced radiation damage make the zircon U-Pb clock either more susceptible to the relatively short heat pulse of the impact event, the moderate pressure and temperature conditions in the peak ring, and/or to hot-fluid flow in the long-lasting post impact hydrothermal system.

Published
2019

26. Rock fluidization during peak-ring formation of large impact structures

Author

Riller, Ulrich, Poelchau, Michael H., Rae, Auriol S. P., Schulte, Felix M., Collins, Gareth S., Melosh, H. Jay, Grieve, Richard A. F., Morgan, Joanna V., Gulick, Sean P. S., Lofi, Johanna, Diaw, Abdoulaye, McCall, Naoma, Kring, David A., Green, Sophie L., Chenot, Elise, Christeson, Gail L., Claeys, Philippe, Cockell, Charles S., Coolen, Marco J. L., Ferrière, Ludovic, Gebhardt, Catalina, Goto, Kazuhisa, Jones, Heather, Long, Xiao, Lowery, Christopher M., Ocampo-Torres, Rubén, Pérez-Cruz, Ligia, Pickersgill, Annemarie E., Rasmussen, Cornelia, Rebolledo-Vieyra, Mario, Sato, Honami, Smit, Jan, Tikoo-Schantz, Sonia M., Tomioka, Naotaka, Whalen, Michael T., Wittmann, Axel, Yamaguchi, Kosei E., Fucugauchi, Jaime Urrutia, Bralower, Timothy J., IODP–ICDP Expedition 364 Science Party, Institut für Geologie, Universität Hamburg (UHH), Department of Geology, University of Freiburg [Freiburg], Department of Earth Science and Engineering [Imperial College London], Imperial College London, Department of Earth, Atmospheric, and Planetary Sciences [West Lafayette] (EAPS), Purdue University [West Lafayette], Centre for Planetary Science and Exploration [London, ON] (CPSX), University of Western Ontario (UWO), Institute of Geophysics [Austin] (IG), University of Texas at Austin [Austin], Department of Geological Sciences [Austin], Jackson School of Geosciences (JSG), University of Texas at Austin [Austin]-University of Texas at Austin [Austin], Géosciences Montpellier, Institut national des sciences de l'Univers (INSU - CNRS)-Université de Montpellier (UM)-Université des Antilles (UA)-Centre National de la Recherche Scientifique (CNRS), Universities Space Research Association (USRA), British Geological Survey [Edinburgh], British Geological Survey (BGS), Biogéosciences [UMR 6282] [Dijon] (BGS), Université de Bourgogne (UB)-AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement-Centre National de la Recherche Scientifique (CNRS), Analytical, Environmental and Geo- Chemistry, Vrije Universiteit Brussel (VUB), SUPA School of Physics and Astronomy [Edinburgh], University of Edinburgh, WA-Organic and Isotope Geochemistry Centre (WA-OIGC), The Institute for Geoscience Research [Perth] (TIGeR), School of Earth and Planetary Science [Perth - Curtin university], Curtin University [Perth], Planning and Transport Research Centre (PATREC)-Planning and Transport Research Centre (PATREC)-Curtin University [Perth], Planning and Transport Research Centre (PATREC)-Planning and Transport Research Centre (PATREC)-School of Earth and Planetary Science [Perth - Curtin university], Planning and Transport Research Centre (PATREC)-Planning and Transport Research Centre (PATREC), Natural History Museum [Vienna] (NHM), Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung (AWI), International Research Institute of Disaster Science, Tohoku University [Sendai], Pennsylvania State University (Penn State), Penn State System, China University of Geosciences [Beijing], Institut de chimie et procédés pour l'énergie, l'environnement et la santé (ICPEES), Université de Strasbourg (UNISTRA)-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Instituto de Geofisica [Mexico], Universidad Nacional Autónoma de México (UNAM), School of Geographical and Earth Sciences, University of Glasgow, NERC Argon Isotope Facility [Glasgow], Scottish Universities Environmental Research Centre (SUERC), University of Glasgow-University of Edinburgh-University of Glasgow-University of Edinburgh-Natural Environment Research Council (NERC), Unidad de Ciencias del Agua, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Faculty of Earth and Life Sciences [Amsterdam] (FALW), Vrije Universiteit Amsterdam [Amsterdam] (VU), Department of Earth and Planetary Sciences [Piscataway], Rutgers, The State University of New Jersey [New Brunswick] (RU), Rutgers University System (Rutgers)-Rutgers University System (Rutgers), Kochi Institute for Core Sample Research, Department of Geosciences, University of Alaska [Fairbanks] (UAF), Eyring Materials Center, Arizona State University [Tempe] (ASU), Department of Chemistry, Toho University, NASA Astrobiology Institute (NAI), Work supported by the Priority Programs 527 and 1006 of the German Science Foundation (grants Ri 916/16-1 and PO 1815/2-1), National Science Foundation grants (OCE-1737351, OCE-1450528 and OCE-1736826), and Natural Environment Research Council (grants NE/P011195/1 and NE/P005217/1), by the European Consortium for Ocean Research Drilling (ECORD) and the IODP as Expedition 364 with co-funding from the ICDP., Science and Technology Facilities Council (STFC), Natural Environment Research Council (NERC), Analytical, Environmental & Geo-Chemistry, Earth System Sciences, and Chemistry

Subjects
Solar System, 010504 meteorology & atmospheric sciences, ACOUSTIC FLUIDIZATION, General Science & Technology, Flow (psychology), [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Deformation (meteorology), 010502 geochemistry & geophysics, 01 natural sciences, Brittleness, DEFORMATION, Fluidization, Impact structure, Petrology, COLLAPSE, IODP–ICDP Expedition 364 Science Party, 0105 earth and related environmental sciences, Multidisciplinary, Science & Technology, EXAMPLE, Drilling, SIMULATIONS, CHICXULUB CRATER, Multidisciplinary Sciences, TARGET, Meteorite, SUDBURY, general, ASYMMETRY, Science & Technology - Other Topics, VREDEFORT, Geology
Abstract

8 pages; International audience; Large meteorite impact structures on the terrestrial bodies of the Solar System contain pronounced topographic rings, which emerged from uplifted target (crustal) rocks within minutes of impact. To flow rapidly over large distances, these target rocks must have weakened drastically, but they subsequently regained sufficient strength to build and sustain topographic rings. The mechanisms of rock deformation that accomplish such extreme change in mechanical behaviour during cratering are largely unknown and have been debated for decades. Recent drilling of the approximately 200-km-diameter Chicxulub impact structure in Mexico has produced a record of brittle and viscous deformation within its peak-ring rocks. Here we show how catastrophic rock weakening upon impact is followed by an increase in rock strength that culminated in the formation of the peak ring during cratering. The observations point to quasi-continuous rock flow and hence acoustic fluidization as the dominant physical process controlling initial cratering, followed by increasingly localized faulting.

Published
2018

29. Shaping of the Present-Day Deep Biosphere at Chicxulub by the Impact Catastrophe That Ended the Cretaceous.

Author

Cockell, Charles S., Schaefer, Bettina, Wuchter, Cornelia, Coolen, Marco J. L., Grice, Kliti, Schnieders, Luzie, Morgan, Joanna V., Gulick, Sean P. S., Wittmann, Axel, Lofi, Johanna, Christeson, Gail L., Kring, David A., Whalen, Michael T., Bralower, Timothy J., Osinski, Gordon R., Claeys, Philippe, Kaskes, Pim, de Graaff, Sietze J., Déhais, Thomas, and Goderis, Steven

Subjects
BIOSPHERE, GRANITE, FLUID flow, MICROBIAL communities, CENOZOIC Era
Abstract

We report on the effect of the end-Cretaceous impact event on the present-day deep microbial biosphere at the impact site. IODP-ICDP Expedition 364 drilled into the peak ring of the Chicxulub crater, México, allowing us to investigate the microbial communities within this structure. Increased cell biomass was found in the impact suevite, which was deposited within the first few hours of the Cenozoic, demonstrating that the impact produced a new lithological horizon that caused a long-term improvement in deep subsurface colonization potential. In the biologically impoverished granitic rocks, we observed increased cell abundances at impact-induced geological interfaces, that can be attributed to the nutritionally diverse substrates and/or elevated fluid flow. 16S rRNA gene amplicon sequencing revealed taxonomically distinct microbial communities in each crater lithology. These observations show that the impact caused geological deformation that continues to shape the deep subsurface biosphere at Chicxulub in the present day. [ABSTRACT FROM AUTHOR]

Published
2021
Full Text
View/download PDF

31. Life and death in the Chicxulub impact crater: A record of the Paleocene-Eocene Thermal Maximum.

Author

Smith, Vann, Warny, Sophie, Grice, Kliti, Schaefer, Bettina, Whalen, Michael T., Vellekoop, Johan, Chenot, Elise, Gulick, Sean P. S., Arenillas, Ignacio, Arz, Jose A., Bauersachs, Thorsten, Bralower, Timothy, Demory, François, Gattacceca, Jerôme, Jones, Heather, Lofi, Johanna, Lowery, Christopher M., Morgan, Joanna, Nuñez Otaño, Noelia B., and O'Keefe, Jennifer M. K.

Abstract

Thermal stress on the biosphere during the extreme warmth of the Paleocene-Eocene Thermal Maximum (PETM) was most severe at low latitudes, with sea surface temperatures at some localities exceeding the 35 °C at which marine organisms experience heat stress. Relatively few equivalent terrestrial sections have been identified, and the response of land plants to this extreme heat is still poorly understood. Here, we present a new PETM record from the peak ring of the Chicxulub impact crater that has been identified based on nannofossil biostratigraphy, an acme of the dinoflagellate genus Apectodinium, and a negative carbon isotope excursion. Geochemical and microfossil proxies show that the PETM is marked by elevated TEX86H-based sea surface temperatures (SSTs) averaging ~37.8 °C, an increase in terrestrial input, surface productivity, salinity stratification, and bottom water anoxia, with biomarkers for green and purple sulfur bacteria indicative of photic zone euxinia in the early part of the event. Pollen and plants spores in this core provide the first PETM floral assemblage described from México, Central America, and the northern Caribbean. The source area was a diverse coastal shrubby tropical forest, with a remarkably high abundance of fungal spores indicating humid conditions. Thus, while seafloor anoxia devastated the benthic marine biota, and dinoflagellate assemblages were heat-stressed, the terrestrial plant ecosystem thrived. [ABSTRACT FROM AUTHOR]

Published
2020
Full Text
View/download PDF

34. The first day of the Cenozoic.

Author

Gulick, Sean P. S., Bralower, Timothy J., Ormö, Jens, Halle, Brendon, Grice, Kliti, Schaefer, Bettina, Lyons, Shelby, Freeman, Katherine H., Morgan, Joanna V., Artemieva, Natalia, Kaskesi, Pim, de Graaff, Sietze J., Whalen, Michael T., Collins, Gareth S., Tikoo, Sonia M., Verhagen, Christina, Christeson, Gail L., Claeys, Philippe, Coolen, Marco J. L., and Goderis, Steven

Subjects
DRILL core analysis, CAP rock, GLOBAL cooling, POLYCYCLIC aromatic hydrocarbons, EVAPORITES
Abstract

Highly expanded Cretaceous-Paleogene (K-Pg) boundary section from the Chicxulub peak ring, recovered by International Ocean Discovery Program (IODP)-International Continental Scientific Drilling Program (ICDP) Expedition 364, provides an unprecedented window into the immediate aftermath of the impact. Site M0077 includes ~130 m of impact melt rock and suevite deposited the first day of the Cenozoic covered by <1 m of micrite-rich carbonate deposited over subsequent weeks to years. We present an interpreted series of events based on analyses of these drill cores. Within minutes of the impact, centrally uplifted basement rock collapsed outward to forma peak ring capped in melt rock. Within tens of minutes, the peak ring was covered in ~40 m of brecciated impact melt rock and coarsegrained suevite, including clasts possibly generated by melt-water interactions during ocean resurge. Within an hour, resurge crested the peak ring, depositing a 10-m-thick layer of suevite with increased particle roundness and sorting.Within hours, the full resurge deposit formed through settling and seiches, resulting in an 80-m-thick fining-upward, sorted suevite in the flooded crater. Within a day, the reflected rim-wave tsunami reached the crater, depositing a cross-bedded sand-to-fine gravel layer enriched in polycyclic aromatic hydrocarbons overlain by charcoal fragments. Generation of a deep crater open to the ocean allowed rapid flooding and sediment accumulation rates among the highest known in the geologic record. The high-resolution section provides insight into the impact environmental effects, including charcoal as evidence for impactinduced wildfires and a paucity of sulfur-rich evaporites from the target supporting rapid global cooling and darkness as extinction mechanisms. [ABSTRACT FROM AUTHOR]

Published
2019
Full Text
View/download PDF

35. Cretaceous Extinctions: Evidence Overlooked Response

Author

Schulte, Peter, Alegret, Laia, Arenillas, Ignacio, Arz, Jose A, Barton, Penny J, Bown, Paul R, Bralower, Timothy J, Christeson, Gail L, Claeys, Philippe, Cockell, Charles S, Collins, Gareth S, Deutsch, Alexander, Goldin, Tamara J, Goto, Kazuhisa, Grajales-Nishimura, Jose M, Grieve, Richard AF, Gulick, Sean PS, Johnson, Kirk R, Kiessling, Wolfgang, Koeberl, Christian, Kring, David A, Macleod, Kenneth G, Matsui, Takafumi, Melosh, Jay, Montanari, Alessandro, Morgan, Joanna V, Neal, Clive R, Norris, Richard D, Pierazzo, Elisabetta, Ravizza, Greg, Rebolledo-Vieyra, Mario, Reimold, Wolf Uwe, Robin, Eric, Salge, Tobias, Speijer, Robert, Sweet, Arthur R, Urrutia-Fucugauchi, Jaime, Vajda, Vivi, Whalen, Michael T, and Willumsen, Pi S

Subjects
large igneous provinces, sea-level change, mass extinctions, terrestrial, impact, record, paleogene boundary
Abstract

ispartof: Science vol:328 issue:5981 pages:975-976 status: published

Published
2010

42. Response—Cretaceous Extinctions

Author

Schulte, Peter, primary, Alegret, Laia, additional, Arenillas, Ignacio, additional, Arz, José A., additional, Barton, Penny J., additional, Bown, Paul R., additional, Bralower, Timothy J., additional, Christeson, Gail L., additional, Claeys, Philippe, additional, Cockell, Charles S., additional, Collins, Gareth S., additional, Deutsch, Alexander, additional, Goldin, Tamara J., additional, Goto, Kazuhisa, additional, Grajales-Nishimura, José M., additional, Grieve, Richard A. F., additional, Gulick, Sean P. S., additional, Johnson, Kirk R., additional, Kiessling, Wolfgang, additional, Koeberl, Christian, additional, Kring, David A., additional, Macleod, Kenneth G., additional, Matsui, Takafumi, additional, Melosh, Jay, additional, Montanari, Alessandro, additional, Morgan, Joanna V., additional, Neal, Clive R., additional, Norris, Richard D., additional, Pierazzo, Elisabetta, additional, Ravizza, Greg, additional, Rebolledo-Vieyra, Mario, additional, Reimold, Wolf Uwe, additional, Robin, Eric, additional, Salge, Tobias, additional, Speijer, Robert P., additional, Sweet, Arthur R., additional, Urrutia-Fucugauchi, Jaime, additional, Vajda, Vivi, additional, Whalen, Michael T., additional, and Willumsen, Pi S., additional

Published
2010
Full Text
View/download PDF

45. RECONNAISSANCE INVESTIGATION OF THE LISBURNE GROUP IN THE COBBLESTONE CREEK AREA, CHANDLER LAKE QUADRANGLE, ALASKA.

Author

Dumoulin, Julie A. and Whalen, Michael T.

Subjects
*HYDROCARBON reservoirs, *CARBONIFEROUS Period, *THRUST faults (Geology), *PETROLOGY
Abstract

A reconnaissance investigation of the Carboniferous Lisburne Group in the Cobblestone Creek area, Chandler Lake Quadrangle, yields insights into its resource potential and regional relations. Locally porous vuggy dolostone with hydrocarbon reservoir potential occurs in the lower Lisburne in the three most southerly of five thrust sheets, and contains traces of dead oil in two of these sheets. The dolostones are coarse crystalline, commonly cross-bedded, and at least in part of Osagean (late Early Mississippian) age; they have pelmatozoan grainstone protoliths that likely formed in sand shoals of the midramp to inner ramp. Similar, coeval porous dolostones occur in the Lisburne from Skimo Creek to Itkillik Lake, ~70 km west and 10 km east of the Cobblestone Creek area, respectively. We also examined the uppermost Lisburne Group at several localities in the Cobblestone Creek area, mainly in the northernmost thrust sheet where the rocks are as young as Morrowan (Early Pennsylvanian). Cobblestone sections contain more supportstone than equivalent strata at Skimo Creek, and overlying Permian successions also differ between the two areas. These lithologic contrasts may reflect different rates of tectonically controlled subsidence, and (or) changes in sediment input, along the late Paleozoic continental margin. [ABSTRACT FROM AUTHOR]

Published
2015

46. SOURCE-ROCK POTENTIAL OF THE LOWER CRETACEOUS PEBBLE SHALE UNIT, NORTHEASTERN ALASKA.

Author

van der Kolk, Dolores A., Whalen, Michael T., and Wartes, Marwan A.

Subjects
*ROCKS, *HYDROCARBONS, *HYDROGEN, *QUALITY
Abstract

In northeastern Alaska, the Lower Cretaceous pebble shale unit (PSU) was investigated for source-rock potential along the west side of the Canning River (outside of ANWR), along an unnamed tributary east of the Katakturuk River (Boulder Bowl), and at Marsh Creek. Samples were collected and analyzed for total organic carbon (TOC), Rock-Eval, and vitrinite relectance (Ro). Results indicate that there are 12- to 31-m-thick packages of the PSU that have suficient organic content (2-6 wt. percent TOC) to constitute good to excellent source rock. However, Rock-Eval data from these same samples suggest poor source-rock quality (Hydrogen Index [HI] < 50mg Hydrocarbon [HC]/g TOC) likely from elevated thermal maturity of the PSU as indicated by high Tmax and Ro values. The average vitrinite relectance of the sections sampled for this study ranges from 1.28 to 1.79 percent Ro, indicating latest oil window to gas window maturity. Results from this study are consistent with previous studies indicating that the PSU originally had good source-rock potential; however, because of advanced thermal maturity in the study area, the parameters that correspond to source-rock quality indicate considerable degradation. [ABSTRACT FROM AUTHOR]

Published
2015

47. Cyclostratigraphic calibration of the Frasnian (Late Devonian) time scale (western Alberta, Canada).

Author

De Vleeschouwer, David, Whalen, Michael T., Day, James E., and Claeys, Philippe

Subjects
*CYCLOSTRATIGRAPHY, *TIME series analysis, *DEVONIAN Period, *GLOBAL environmental change, *MAGNETIC susceptibility, *BIOSTRATIGRAPHY
Abstract

Until now, the duration of the Frasnian Stage has remained very poorly constrained, hampering a detailed understanding of sedimentation processes and environmental and evolutionary change. In this study, timeseries analyses of high-resolution (10-20 k.y.) magnetic susceptibility data identify sixteen 405 k.y. eccentricity cycles in the magnetic susceptibility stratigraphy of the Frasnian (Late Devonian), derived from carbonate-platform and surrounding slope and basin deposits in western Alberta, Canada. Previous studies demonstrated the generally consistent pattern of magnetic susceptibility change across the Alberta basin and thus demonstrated the utility of magnetic susceptibility stratigraphy as a refined regional correlation tool compared to biostratigraphy. In the present study, we show that the magnetic susceptibility stratigraphy of the Frasnian interval in western Alberta has been significantly influenced by astronomical forcing. Using the sixteen 405 k.y. eccentricity cycles as a geochronometer, we constructed a Frasnian astronomical time scale. This time scale indicates a duration of 6.5 ± 0.4 m.y. for the Frasnian. Calibrating this duration to the best available Devonian chronology, the absolute age of the Givetian-Frasnian boundary is recalculated to 383.6 ± 3.0 Ma, and the age of the Frasnian-Famennian boundary is recalculated to 376.7 ± 3.0 Ma. These new absolute ages take into account the astronomically derived duration of the Frasnian, but they also yield a narrowing of the error margins of the absolute ages by several hundreds of thousands of years. [ABSTRACT FROM AUTHOR]

Published
2012
Full Text
View/download PDF

48. Stable isotope (δ13Ccarb and org, δ15Norg) and trace element anomalies during the Late Devonian ‘punctata Event’ in the Western Canada Sedimentary Basin

Author

Śliwiński, Maciej G., Whalen, Michael T., Newberry, Rainer J., Payne, Joshua H., and Day, Jed E.

Subjects
*STABLE isotopes, *TRACE elements, *SEDIMENTARY basins, *NITROGEN isotopes, *BIOLOGICAL productivity, *STATISTICAL correlation, *EUTROPHICATION, *CARBON isotopes, *GEOCHEMISTRY, DEVONIAN paleoecology
Abstract

Abstract: Late Devonian marine deposits in the Western Canada Sedimentary Basin were analyzed for (1) accumulations of bioproductivity and paleoredox trace element proxies and for (2) variations of δ13C(carb and org) and δ15Norg in order to understand and interpret the regional history of the global yet short-term ‘punctata Event’ geochemical perturbation. Statistical correlations suggest that changes in detrital input and associated micronutrient delivery were the main driver of a eutrophication event noted early and possibly also late in the punctata zone around the isolated Miette platform, manifested by increased TOC, positive δ13C excursions and concurrent enrichments of all elemental proxies. Evaluation of data within a regional sequence stratigraphic perspective revealed a eustatic sea level influence, with proxy accumulations associated mostly with early transgression (IIc1). Deposition and preservation of organic matter-rich facies occurred during conditions of enhanced primary production and facilitated bottom water suboxia–anoxia. Following eutrophication, lower δ15Norg and δ13Corg values predominated and persisted throughout much of the punctata zone before rebounding toward its close, suggesting a time interval of environmental stagnation and lower overall productivity during which N2-fixing autotrophs may have had an ecological advantage under nitrate-limited conditions. The punctata Event approximately coincided with the advent of archaeopterid forest expansion beginning around mid-Frasnian time, which fundamentally altered the nature of continental weathering through extensive soil formation and increased nutrient delivery to the oceans. This evolutionary event may have amplified the detrital influx, already elevated by sea level lowstand and early transgression and increased denudation of rising mountain ranges in near-equatorial regions. [Copyright &y& Elsevier]

Published
2011
Full Text
View/download PDF

49. TRACE ELEMENT VARIATIONS IN THE MIDDLE FRASNIAN PUNCTATA ZONE (LATE DEVONIAN) IN THE WESTERN CANADA SEDIMENTARY BASIN -- CHANGES IN OCEANIC BIOPRODUCTIVITY AND PALEOREDOX SPURRED BY A PULSE OF TERRESTRIAL AFFORESTATION?

Author

ŚLIWIŃSKI, Maciej G., WHALEN, Michael T., and DAY, Jed

Subjects
*TRACE elements, *SEDIMENTARY basins, *GEOCHEMISTRY, *MAGNETIC susceptibility, DEVONIAN stratigraphic geology
Abstract

The 'punctata Event' (Early-Middle Frasnian transition, Late Devonian) was recently recognized as yet another episode of major geochemical perturbations associated with the Middle-Late Devonian ecosystem readjustments which culminated in the Frasnian-Fammenian (F/F) mass extinction event, one of five largest of the Phanerozoic. We report variations in total organic carbon (TOC), magnetic susceptibility (MS), major, minor and trace element proxies (for changes in detrital input, bioproductivity and redox conditions) across the P. punctata conodont biozone in the Western Canada Sedimentary Basin (Western Laurussia). Geochemical proxies and MS display similar trends, suggesting an intimate interdependence. The data is thus evaluated within 1) a regional sequence stratigraphic perspective and 2) the marine-terrestrial teleconnections model (Algeo & Sheckler, 1998), whereby the rise and expansion of arborescent vascular land plants (the first 'true' forests) results in a transient increase in pedogenesis and solute delivery (hence biolimiting micronutrients) to the oceans. The punctata Event approximately coincides temporally with the advent of archaeopterid forest expansion and rise to dominance in the Frasnian-Fammenian age. This evolutionary event is speculated to have amplified the detrital influx which was likely already elevated by conditions of sea level lowstand, early transgression, episodes of mountain building and increased weathering during Frasnian warming. Statistical correlations among proxies suggest that changes in detrital input were the main driver of a bioproductivity increase. Elevated organic matter export from the photic zone likely led to the deposition and later preservation of organic-carbon rich facies under facilitated conditions of bottom water oxygen depletion. This paper is intended to supplement the growing body of work aimed at elucidating the causes of the punctata Event and documenting ecosystem responses to major perturbations of the global carbon cycle. [ABSTRACT FROM AUTHOR]

Published
2010

50. Large sulphur isotopic perturbations and oceanic changes during the Frasnian-Famennian transition of the Late Devonian.

Author

DAIZHAO CHEN, JIANGUO WANG, RACKI, GRZEGORZ, HUA LI, CHENGYUAN WANG, XUEPING MA, and WHALEN, MICHAEL T.

Subjects
SULFUR isotopes, CARBONATE analysis, FAMENNIAN Stage, DEVONIAN Period, SULFATES, PHANEROZOIC Eon
Abstract

The Frasnian-Famennian transition of the Late Devonian was one of the most critical intervals in the Phanerozoic. Sulphur isotopic pairs of carbonate-associated sulphate and pyrite sulphide from coeval sections in South China and Poland reveal frequent perturbations of sulphur cycling during this time interval. These data suggest a sudden oceanic overturn during a rapid sea-level fall probably induced by jerky block tilting in the latest Frasnian. This event was followed by long-lasting photic-zone euxinia during a rapid sea-level rise in the earliest Famennian. Large increases in continental nutrient fluxes, and subsequent primary productivity and organic burial, could have greatly enhanced bacterial sulphate reduction, producing excessive sulphide through the water columns owing to iron depletion. Subsequently, rapid ventilation of oceanic basins occurred, during which direct aerobic oxidation of sulphide into sulphate predominated in bottom waters and even surface sediments with minimal fractionation. This oxygenation was probably induced by intensive climatic cooling and/or large-scale sea-level fall. The temporal coincidence of two extinction phases with the oceanic overturn and succeeding photic-zone euxinia suggests that these extreme oceanic events played an important role in the severe biotic crisis. Furthermore, photic-zone euxinia coupled with subsequent climatic cooling may have delayed post-extinction recovery of some taxa. [ABSTRACT FROM AUTHOR]

Published
2013
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results