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标题：Massive and rapid predominantly volcanic CO ₂ emission during the end-Permian mass extinction
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作者：Ying Cui ; Mingsong Li ; Elsbeth E. van Soelen 等
期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2021
卷号：118
期号：37
DOI：10.1073/pnas.2014701118
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Significance The end-Permian mass extinction event (ca. 252 Mya) is the most-severe biodiversity loss in Earth’s history and is globally recognized by a rapid negative carbon isotope excursion. The trigger of this event, however, remains controversial. New paired terrestrial and marine compound-specific carbon isotope records may provide clues for this enigma. By comparing observed data to results from an isotope-enabled Earth system model, we find that a massive and rapid, predominantly volcanic CO 2 emission during the Siberian Traps volcanism is likely the trigger for the carbon isotope excursion and the severe mass extinction. Our findings provide quantitative constraints of how a massive and rapid increase in CO 2 may have influenced the marine ecosystem 252 Mya. The end-Permian mass extinction event (∼252 Mya) is associated with one of the largest global carbon cycle perturbations in the Phanerozoic and is thought to be triggered by the Siberian Traps volcanism. Sizable carbon isotope excursions (CIEs) have been found at numerous sites around the world, suggesting massive quantities of 13C-depleted CO 2 input into the ocean and atmosphere system. The exact magnitude and cause of the CIEs, the pace of CO 2 emission, and the total quantity of CO 2, however, remain poorly known. Here, we quantify the CO 2 emission in an Earth system model based on new compound-specific carbon isotope records from the Finnmark Platform and an astronomically tuned age model. By quantitatively comparing the modeled surface ocean pH and boron isotope pH proxy, a massive (∼36,000 Gt C) and rapid emission (∼5 Gt C yr −1) of largely volcanic CO 2 source (∼−15%) is necessary to drive the observed pattern of CIE, the abrupt decline in surface ocean pH, and the extreme global temperature increase. This suggests that the massive amount of greenhouse gases may have pushed the Earth system toward a critical tipping point, beyond which extreme changes in ocean pH and temperature led to irreversible mass extinction. The comparatively amplified CIE observed in higher plant leaf waxes suggests that the surface waters of the Finnmark Platform were likely out of equilibrium with the initial massive centennial-scale release of carbon from the massive Siberian Traps volcanism, supporting the rapidity of carbon injection. Our modeling work reveals that carbon emission pulses are accompanied by organic carbon burial, facilitated by widespread ocean anoxia.
关键词：enend-Permian mass extinction;compound specific carbon isotopes;CO2;Earth system model