Molecular and isotopic evidence reveals the end-Triassic carbon isotope excursion is not from massive exogenous light carbon
© 2020 National Academy of Sciences. All rights reserved. The negative organic carbon isotope excursion (CIE) associated with the end-Triassic mass extinction (ETE) is conventionally interpreted as the result of a massive flux of isotopically light carbon from exogenous sources into the atmosphere (...
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ftmit:oai:dspace.mit.edu:1721.1/133845.2 2023-06-11T04:15:41+02:00 Molecular and isotopic evidence reveals the end-Triassic carbon isotope excursion is not from massive exogenous light carbon Fox, Calum P Cui, Xingqian Whiteside, Jessica H Olsen, Paul E Summons, Roger E Grice, Kliti 2021-09-23T16:13:08Z application/octet-stream https://hdl.handle.net/1721.1/133845.2 en eng National Academy of Sciences http://dx.doi.org/10.1073/PNAS.1917661117 Proceedings of the National Academy of Sciences 1091-6490 0027-8424 https://hdl.handle.net/1721.1/133845.2 Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. PNAS Article http://purl.org/eprint/type/JournalArticle 2021 ftmit https://doi.org/10.1073/PNAS.1917661117 2023-05-29T08:34:35Z © 2020 National Academy of Sciences. All rights reserved. The negative organic carbon isotope excursion (CIE) associated with the end-Triassic mass extinction (ETE) is conventionally interpreted as the result of a massive flux of isotopically light carbon from exogenous sources into the atmosphere (e.g., thermogenic methane and/or methane clathrate dissociation linked to the Central Atlantic Magmatic Province [CAMP]). Instead, we demonstrate that at its type locality in the Bristol Channel Basin (UK), the CIE was caused by a marine to nonmarine transition resulting from an abrupt relative sea level drop. Our biomarker and compound-specific carbon isotopic data show that the emergence of microbial mats, influenced by an influx of fresh to brackish water, provided isotopically light carbon to both organic and inorganic carbon pools in centimeter-scale water depths, leading to the negative CIE. Thus, the iconic CIE and the disappearance of marine biota at the type locality are the result of local environmental change and do not mark either the global extinction event or input of exogenous light carbon into the atmosphere. Instead, the main extinction phase occurs slightly later in marine strata, where it is coeval with terrestrial extinctions and ocean acidification driven by CAMP-induced increases in PCO2; these effects should not be conflated with the CIE. An abrupt sea-level fall observed in the Central European basins reflects the tectonic consequences of the initial CAMP emplacement, with broad implications for all extinction events related to large igneous provinces. Article in Journal/Newspaper Ocean acidification DSpace@MIT (Massachusetts Institute of Technology) Proceedings of the National Academy of Sciences 117 48 30171 30178 |
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English |
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© 2020 National Academy of Sciences. All rights reserved. The negative organic carbon isotope excursion (CIE) associated with the end-Triassic mass extinction (ETE) is conventionally interpreted as the result of a massive flux of isotopically light carbon from exogenous sources into the atmosphere (e.g., thermogenic methane and/or methane clathrate dissociation linked to the Central Atlantic Magmatic Province [CAMP]). Instead, we demonstrate that at its type locality in the Bristol Channel Basin (UK), the CIE was caused by a marine to nonmarine transition resulting from an abrupt relative sea level drop. Our biomarker and compound-specific carbon isotopic data show that the emergence of microbial mats, influenced by an influx of fresh to brackish water, provided isotopically light carbon to both organic and inorganic carbon pools in centimeter-scale water depths, leading to the negative CIE. Thus, the iconic CIE and the disappearance of marine biota at the type locality are the result of local environmental change and do not mark either the global extinction event or input of exogenous light carbon into the atmosphere. Instead, the main extinction phase occurs slightly later in marine strata, where it is coeval with terrestrial extinctions and ocean acidification driven by CAMP-induced increases in PCO2; these effects should not be conflated with the CIE. An abrupt sea-level fall observed in the Central European basins reflects the tectonic consequences of the initial CAMP emplacement, with broad implications for all extinction events related to large igneous provinces. |
format |
Article in Journal/Newspaper |
author |
Fox, Calum P Cui, Xingqian Whiteside, Jessica H Olsen, Paul E Summons, Roger E Grice, Kliti |
spellingShingle |
Fox, Calum P Cui, Xingqian Whiteside, Jessica H Olsen, Paul E Summons, Roger E Grice, Kliti Molecular and isotopic evidence reveals the end-Triassic carbon isotope excursion is not from massive exogenous light carbon |
author_facet |
Fox, Calum P Cui, Xingqian Whiteside, Jessica H Olsen, Paul E Summons, Roger E Grice, Kliti |
author_sort |
Fox, Calum P |
title |
Molecular and isotopic evidence reveals the end-Triassic carbon isotope excursion is not from massive exogenous light carbon |
title_short |
Molecular and isotopic evidence reveals the end-Triassic carbon isotope excursion is not from massive exogenous light carbon |
title_full |
Molecular and isotopic evidence reveals the end-Triassic carbon isotope excursion is not from massive exogenous light carbon |
title_fullStr |
Molecular and isotopic evidence reveals the end-Triassic carbon isotope excursion is not from massive exogenous light carbon |
title_full_unstemmed |
Molecular and isotopic evidence reveals the end-Triassic carbon isotope excursion is not from massive exogenous light carbon |
title_sort |
molecular and isotopic evidence reveals the end-triassic carbon isotope excursion is not from massive exogenous light carbon |
publisher |
National Academy of Sciences |
publishDate |
2021 |
url |
https://hdl.handle.net/1721.1/133845.2 |
genre |
Ocean acidification |
genre_facet |
Ocean acidification |
op_source |
PNAS |
op_relation |
http://dx.doi.org/10.1073/PNAS.1917661117 Proceedings of the National Academy of Sciences 1091-6490 0027-8424 https://hdl.handle.net/1721.1/133845.2 |
op_rights |
Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. |
op_doi |
https://doi.org/10.1073/PNAS.1917661117 |
container_title |
Proceedings of the National Academy of Sciences |
container_volume |
117 |
container_issue |
48 |
container_start_page |
30171 |
op_container_end_page |
30178 |
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1768372693216788480 |