Chinese Academy of Sciences Key Laboratory of Crust-Mantle Materials and Environments, School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026, China.
School of Resources and Environmental Engineering, Hefei University of Technology, Hefei 230009, China.
Proc Natl Acad Sci U S A. 2018 Apr 10;115(15):3782-3787. doi: 10.1073/pnas.1711862115. Epub 2018 Mar 26.
Lithium (Li) isotope analyses of sedimentary rocks from the Meishan section in South China reveal extremely light seawater Li isotopic signatures at the Permian-Triassic boundary (PTB), which coincide with the most severe mass extinction in the history of animal life. Using a dynamic seawater lithium box model, we show that the light seawater Li isotopic signatures can be best explained by a significant influx of riverine [Li] with light δLi to the ocean realm. The seawater Li isotope excursion started ≥300 Ky before and persisted up to the main extinction event, which is consistent with the eruption time of the Siberian Traps. The eruption of the Siberian Traps exposed an enormous amount of fresh basalt and triggered CO release, rapid global warming, and acid rains, which in turn led to a rapid enhancement of continental weathering. The enhanced continental weathering delivered excessive nutrients to the oceans that could lead to marine eutrophication, anoxia, acidification, and ecological perturbation, ultimately resulting in the end-Permian mass extinction.
中国南方梅汕剖面的沉积岩锂同位素分析显示，在二叠纪-三叠纪之交（PTB），海水的锂同位素组成极其轻，这与动物生命史上最严重的大灭绝事件相吻合。利用一个动态海水锂箱模型，我们表明，海水锂同位素的轻微变化可以最好地解释为大量的河流[Li]与轻 δLi 涌入海洋领域。海水锂同位素的偏移开始于主灭绝事件之前的≥300 千年前，并持续到主灭绝事件，这与西伯利亚地盾的喷发时间一致。西伯利亚地盾的喷发暴露了大量的新鲜玄武岩，并引发了 CO 释放、快速的全球变暖以及酸雨，这反过来又导致了大陆风化的迅速增强。增强的大陆风化将过多的营养物质输送到海洋，可能导致海洋富营养化、缺氧、酸化和生态扰动，最终导致二叠纪末大灭绝。
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