Lithium isotopic evidence for enhanced reverse weathering during the Early Triassic warm period

• 成果类型: Article
• 署名作者: Rauzi, Sofia; Foster, William J.; Takahashi, Satoshi; Hori, Rie S.; Beaty, Brian J.; Tarhan, Lidya G.; Isson, Terry
• 署名单位: University of Waikato; University of Hamburg; Nagoya University; Ehime University; Yale University
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-11599
• DOI: 10.1073/pnas.2318860121
• 发表日期: 2024-08-06
• 关键词: biotic recovery; subduction zone; mass-balance; pore fluids; fractionation; sediments; seawater; cycle; silica; stabilization

摘要

Elevated temperatures persisted for an anomalously protracted interval following pulsed volcanic carbon release associated with the end- Permian mass extinction, deviating from the expected timescale of climate recovery following a carbon injection event. Here, we present evidence for enhanced reverse weathering-a CO2 source-following the end- Permian mass extinction based on the lithium isotopic composition of marine shales and cherts. We find that the average lithium isotopic composition of Lower Triassic marine shales is significantly elevated relative to that of all other previously measured Phanerozoic marine shales. Notably, the record generated here conflicts with carbonate- based interpretations of the lithium isotopic composition of Early Triassic seawater, forcing a re- evaluation of the existing framework used to interpret lithium isotopes in sedimentary archives. Using a stochastic forward lithium cycle model, we demonstrate that elevated reverse weathering is required to reproduce the lithium isotopic values and trends observed in Lower Triassic marine shales and cherts. Collectively, this work provides direct geochemical evidence for enhanced reverse weathering in the aftermath of Earth's most severe mass extinction.