Molecular and isotopic evidence reveals the end-Triassic carbon isotope excursion is not from massive exogenous light carbon.

ABSTRACT: 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-sc

SUBMITTER: Fox CP 

PROVIDER: S-EPMC7720136 | biostudies-literature | 2020 Dec

REPOSITORIES: biostudies-literature