The release of climatic gases by the Chicxulub impact

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doi: 10.1130/abs/2017AM-301942
Author(s): Morgan, Joanna V.; Artemieva, Natalia; Gulick, Sean S. P.; Collins, Gareth S.
Author Affiliation(s): Primary:
Imperial College London, Department of Earth Science and Engineering, London, United Kingdom
Planetary Science Institute, United States
University of Texas at Austin, United States
Volume Title: Geological Society of America, 2017 annual meeting & exposition
Source: Abstracts with Programs - Geological Society of America, 49(6); Geological Society of America, 2017 annual meeting & exposition, Seattle, WA, Oct. 22-25, 2017. Publisher: Geological Society of America (GSA), Boulder, CO, United States. ISSN: 0016-7592 CODEN: GAAPBC
Note: In English
Summary: The cause of the K-Pg mass extinction remains a matter of some debate. Here, we revisit the release of climatically-active gases from carbonates and evaporites at the Chicxulub impact site, and use the multi-phase SOVA hydrocode to simulate the impact. Due to improvements in EOS, hydrocode capability, and computational power, we are able to more accurately estimate the proportion of degassed sedimentary rocks that are ejected to sufficiently high altitudes (> 25 km) to have had global consequences. New evidence from 3D simulations of crater formation suggests that the impact angle was about 60 degrees with a downrange direction to the southwest, which means that we can better constrain the location of the sedimentary rock sequence that was degassed. We estimate the thickness and composition of the sedimentary section using the nearest onshore boreholes and marine seismic reflection profiles. We explore the effect of varying impact angle by ±10 degrees, as well as changing the shock pressure at which incipient and complete degassing of calcite occurs by ±20 GPa. We also investigate the difference in released sulfur if the evaporite is anhydrite or gypsum, and the effect of submerging the sedimentary sequence under water. Recent Global Climate Models indicate that the released sulfur and CO2 would lead to a dramatic decrease of > 20 degrees C in temperature at the Earth's surface, sub-freezing temperatures for > 3 years, and changes in ocean temperatures for 100s years. The European Consortium for Ocean Drilling (ECORD) implemented Expedition 364 with funding from the International Ocean Discovery Program (IODP) and the International Continental scientific Drilling Project (ICDP).
Year of Publication: 2017
Research Program: IODP2 International Ocean Discovery Program
Key Words: 12 Stratigraphy, Historical Geology and Paleoecology; Atlantic Ocean; Chicxulub Crater; Expedition 364; Gulf of Mexico; International Continental Scientific Drilling Program; International Ocean Discovery Program; Mass extinctions; North Atlantic; Paleoclimatology; Paleoecology
Record ID: 2018022327
Copyright Information: GeoRef, Copyright 2018 American Geosciences Institute. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States

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