Molecular and isotopic evidence reveals the end-Triassic carbon isotope excursion is not from massive exogenous light carbon
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 dissoci...
| Main Authors: | , , , , , |
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| Format: | Journal Article |
| Language: | English |
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NATL ACAD SCIENCES
2020
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| Online Access: | https://dspace.mit.edu/handle/1721.1/133845.2 http://hdl.handle.net/20.500.11937/90127 |
| _version_ | 1848765332541407232 |
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| author | Fox, Calum P. Cui, X. Whiteside, J.H. Olsen, P.E. Summons, R.E. Grice, Kliti |
| author_facet | Fox, Calum P. Cui, X. Whiteside, J.H. Olsen, P.E. Summons, R.E. Grice, Kliti |
| author_sort | Fox, Calum P. |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | 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. |
| first_indexed | 2025-11-14T11:33:34Z |
| format | Journal Article |
| id | curtin-20.500.11937-90127 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| language | English |
| last_indexed | 2025-11-14T11:33:34Z |
| publishDate | 2020 |
| publisher | NATL ACAD SCIENCES |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-901272023-02-23T07:31:20Z Molecular and isotopic evidence reveals the end-Triassic carbon isotope excursion is not from massive exogenous light carbon Fox, Calum P. Cui, X. Whiteside, J.H. Olsen, P.E. Summons, R.E. Grice, Kliti Science & Technology Multidisciplinary Sciences Science & Technology - Other Topics large igneous provinces carbon isotopes end-Triassic mass extinction biomarkers PHOTIC ZONE EUXINIA SEA-LEVEL CHANGE JURASSIC BOUNDARY HORIZONS ATLANTIC MAGMATIC PROVINCE FRESH-WATER MICROBIALITES LOWER RHINE BASIN PALEOENVIRONMENTAL CONDITIONS 2-METHYLHOPANOID PRODUCTION FACIES DEVELOPMENT CUATRO CIENEGAS 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. 2020 Journal Article http://hdl.handle.net/20.500.11937/90127 10.1073/pnas.1917661117 English https://dspace.mit.edu/handle/1721.1/133845.2 http://purl.org/au-research/grants/arc/LP150100341 http://purl.org/au-research/grants/arc/LE110100119 http://purl.org/au-research/grants/arc/LE100100041 http://purl.org/au-research/grants/arc/LE0882836 NATL ACAD SCIENCES restricted |
| spellingShingle | Science & Technology Multidisciplinary Sciences Science & Technology - Other Topics large igneous provinces carbon isotopes end-Triassic mass extinction biomarkers PHOTIC ZONE EUXINIA SEA-LEVEL CHANGE JURASSIC BOUNDARY HORIZONS ATLANTIC MAGMATIC PROVINCE FRESH-WATER MICROBIALITES LOWER RHINE BASIN PALEOENVIRONMENTAL CONDITIONS 2-METHYLHOPANOID PRODUCTION FACIES DEVELOPMENT CUATRO CIENEGAS Fox, Calum P. Cui, X. Whiteside, J.H. Olsen, P.E. Summons, R.E. Grice, Kliti Molecular and isotopic evidence reveals the end-Triassic carbon isotope excursion is not from massive exogenous light carbon |
| title | 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_short | 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 |
| topic | Science & Technology Multidisciplinary Sciences Science & Technology - Other Topics large igneous provinces carbon isotopes end-Triassic mass extinction biomarkers PHOTIC ZONE EUXINIA SEA-LEVEL CHANGE JURASSIC BOUNDARY HORIZONS ATLANTIC MAGMATIC PROVINCE FRESH-WATER MICROBIALITES LOWER RHINE BASIN PALEOENVIRONMENTAL CONDITIONS 2-METHYLHOPANOID PRODUCTION FACIES DEVELOPMENT CUATRO CIENEGAS |
| url | https://dspace.mit.edu/handle/1721.1/133845.2 https://dspace.mit.edu/handle/1721.1/133845.2 https://dspace.mit.edu/handle/1721.1/133845.2 https://dspace.mit.edu/handle/1721.1/133845.2 https://dspace.mit.edu/handle/1721.1/133845.2 http://hdl.handle.net/20.500.11937/90127 |