TY - JOUR
T1 - Organic matter from the Chicxulub crater exacerbated the K-Pg impact winter
AU - Lyons, Shelby L.
AU - Karp, Allison T.
AU - Bralower, Timothy J.
AU - Grice, Kliti
AU - Schaefer, Bettina
AU - Gulick, Sean P.S.
AU - Morgan, Joanna V.
AU - Freeman, Katherine H.
N1 - Funding Information:
ACKNOWLEDGMENTS. This research used samples and data provided by the International Ocean Discovery Program (IODP). Expedition 364 was funded by the European Consortium for Ocean Research Drilling and the International Continental Scientific Drilling Program, with contributions from the Yucatán State Government and Universidad Nacional Autónoma de México. This study was funded by NSF-OCE 1737351, NSF-OCE 1736951, and Natural Environment Research Council Grant NE/P005217/1. We are grateful to D. Walizer, S. Lincoln, and H. Betz for analytical support. K.G. and B.S. thank the Australian Research Council (ARC) for an ARC-Discovery grant (DP180100982) entitled “The recovery of life recorded at the End-Cretaceous impact crater.” B.S. thanks Curtin University for an Australian postgraduate award. A.T.K. was supported by a NSF Graduate Research Fellowship under Grant DGE1255832. This is University of Texas Institute for Geophysics Contribution #3685 and Center for Planetary Systems Habitability Contribution #0015. We thank the editor and two anonymous reviewers for their contributions to this manuscript.
Funding Information:
This research used samples and data provided by the International Ocean Discovery Program (IODP). Expedition 364 was funded by the European Consortium for Ocean Research Drilling and the International Continental Scientific Drilling Program, with contributions from the Yucat?n State Government and Universidad Nacional Aut?noma de M?xico. This study was funded by NSF-OCE 1737351, NSF-OCE 1736951, and Natural Environment Research Council Grant NE/P005217/1. We are grateful to D. Walizer, S. Lincoln, and H. Betz for analytical support. K.G. and B.S. thank the Australian Research Council (ARC) for an ARC-Discovery grant (DP180100982) entitled "The recovery of life recorded at the End-Cretaceous impact crater." B.S. thanks Curtin University for an Australian postgraduate award. A.T.K. was supported by a NSF Graduate Research Fellowship under Grant DGE1255832. This is University of Texas Institute for Geophysics Contribution #3685 and Center for Planetary Systems Habitability Contribution #0015. We thank the editor and two anonymous reviewers for their contributions to this manuscript.
Publisher Copyright:
© 2020 National Academy of Sciences. All rights reserved.
PY - 2020/10/13
Y1 - 2020/10/13
N2 - An asteroid impact in the Yucatán Peninsula set off a sequence of events that led to the Cretaceous-Paleogene (K-Pg) mass extinction of 76% species, including the nonavian dinosaurs. The impact hit a carbonate platform and released sulfate aerosols and dust into Earth's upper atmosphere, which cooled and darkened the planet - a scenario known as an impact winter. Organic burn markers are observed in K-Pg boundary records globally, but their source is debated. If some were derived from sedimentary carbon, and not solely wildfires, it implies soot from the target rock also contributed to the impact winter. Characteristics of polycyclic aromatic hydrocarbons (PAHs) in the Chicxulub crater sediments and at two deep ocean sites indicate a fossil carbon source that experienced rapid heating, consistent with organic matter ejected during the formation of the crater. Furthermore, PAH size distributions proximal and distal to the crater indicate the ejected carbon was dispersed globally by atmospheric processes. Molecular and charcoal evidence indicates wildfires were also present but more delayed and protracted and likely played a less acute role in biotic extinctions than previously suggested. Based on stratigraphy near the crater, between 7.5 × 1014and 2.5 × 1015g of black carbon was released from the target and ejected into the atmosphere, where it circulated the globe within a few hours. This carbon, together with sulfate aerosols and dust, initiated an impact winter and global darkening that curtailed photosynthesis and is widely considered to have caused the K-Pg mass extinction.
AB - An asteroid impact in the Yucatán Peninsula set off a sequence of events that led to the Cretaceous-Paleogene (K-Pg) mass extinction of 76% species, including the nonavian dinosaurs. The impact hit a carbonate platform and released sulfate aerosols and dust into Earth's upper atmosphere, which cooled and darkened the planet - a scenario known as an impact winter. Organic burn markers are observed in K-Pg boundary records globally, but their source is debated. If some were derived from sedimentary carbon, and not solely wildfires, it implies soot from the target rock also contributed to the impact winter. Characteristics of polycyclic aromatic hydrocarbons (PAHs) in the Chicxulub crater sediments and at two deep ocean sites indicate a fossil carbon source that experienced rapid heating, consistent with organic matter ejected during the formation of the crater. Furthermore, PAH size distributions proximal and distal to the crater indicate the ejected carbon was dispersed globally by atmospheric processes. Molecular and charcoal evidence indicates wildfires were also present but more delayed and protracted and likely played a less acute role in biotic extinctions than previously suggested. Based on stratigraphy near the crater, between 7.5 × 1014and 2.5 × 1015g of black carbon was released from the target and ejected into the atmosphere, where it circulated the globe within a few hours. This carbon, together with sulfate aerosols and dust, initiated an impact winter and global darkening that curtailed photosynthesis and is widely considered to have caused the K-Pg mass extinction.
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U2 - 10.1073/pnas.2004596117
DO - 10.1073/pnas.2004596117
M3 - Article
C2 - 32989138
AN - SCOPUS:85092914280
SN - 0027-8424
VL - 117
SP - 25327
EP - 25334
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 41
ER -