大火成岩省与二叠纪两次生物灭绝关系研究进展

The Link between Large Igneous Provinces and the Two Mass Extinctions in Permian: Review of Recent Progress

二叠纪两次生物灭绝事件一直是地质学家所关注和研究的热点问题。一次是地质历史上规模最大的晚二叠世乐平期末生物灭绝事件(Permian—Triassic boundary——PTB,约252Ma),导致超过95%的海洋物种消失和全球生物化学圈紊乱;另一次是规模相对较小的中二叠世瓜德鲁普期末(end-Guadalupian,Guadalupian—Lopingian boundary——GLB,约260Ma)生物灭绝事件。尽管这两次生物灭绝的原因尚不完全清楚,但巧合的是,这两次生物灭绝事件在时间上分别与西伯利亚和峨眉山大火成岩省火山活动存在耦合关系。一般认为,火山活动导致生物灭绝主要机制是其产生大量挥发性气体和火山灰引发全球性环境气候急剧恶化的结果。本文回顾近年围绕大火成岩省与这两次生物灭绝耦合关系这一科学问题展开大火成岩省相关地质过程释放挥发性气体量化工作所取得的研究成果,并总结分析一些现阶段仍然存在争议的问题和提出对峨眉山大火成岩省进一步工作的一些建议。

The two mass extinction events in the Permian, debated and investigated by geologists, have been a hottest of issues. In the Permo--Triassic boundary （PTB, about 252 Ma） mass extinction, more than 90% of marine species went extinct, and biogeochemical cycles were disrupted globally. The other smaller mass extinction occurred at the Guadalupian--Lopingian boundary （GLB, end-Guadalupian, about 260 Ma）. Although the origin of the two mass extinction events has been unclear, it is a coincidence that a temporal link between the two mass extinction events and flood basalts volcanisms of the Siberian and Emeishan large igneous provinces. Generally, the volcanism has been considered to be a major cause of mass extinction which caused a sharp deterioration of global climate due to a large quantity of volatile gases and volcanic ash production. This paper reviews, around the coupling relationship between the two mass extinction events and the large igneous provinces, research results of volatile gases release from geological processes associated with large igneous provinces. In the end, we summarize some controversies at the current stage and put forward some suggestions for Emeishan large igneous province.