研究人员根据海洋页岩和燧石的锂同位素组成，提供了二叠纪末大灭绝后逆风化(CO2来源)增强的证据。研究发现，早三叠世海相页岩的平均锂同位素组成，明显高于其他显生宙时期海相页岩。值得注意的是，这里生成的记录与早三叠世海水锂同位素组成的碳酸盐岩解释相冲突，迫使人们重新评估以沉积档案中锂同位素解释为主题的现有框架。
研究利用随机正向锂循环模型，证明了需要增强的反向风化作用，以重现早三叠世海相页岩和燧石中观察到的锂同位素值和趋势。总的来说，这项工作为地球上最严重的大灭绝事件之后增强的反向风化，提供了直接的地球化学证据。
据了解，在与二叠纪末大灭绝相关的脉冲式火山碳释放后，温度升高持续了异常漫长的时间间隔，偏离了碳注入事件后气候恢复的预期时间尺度。
附：英文原文
Title: Lithium isotopic evidence for enhanced reverse weathering during the Early Triassic warm period
Author: Rauzi, Sofia, Foster, William J., Takahashi, Satoshi, Hori, Rie S., Beaty, Brian J., Tarhan, Lidya G., Isson, Terry
Issue&Volume: 2024-7-29
Abstract: 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.
DOI: 10.1073/pnas.2318860121
Source: https://www.pnas.org/doi/abs/10.1073/pnas.2318860121