Middle-Late Permian mass extinction on land
Middle-Late Permian mass extinction on land
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DOI：
10.1130/b26011.1
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发表时间：
2006-11
影响因子：
4.9
通讯作者：
G. Retallack;C. A. Metzger;T. Greaver;A. Jahren;Roger M. H. Smith;N. Sheldon
中科院分区：
文献类型：
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作者：
G. Retallack;C. A. Metzger;T. Greaver;A. Jahren;Roger M. H. Smith;N. Sheldon
二叠纪末的大灭绝被认为是生物多样性下降的最低点，原因是大约900万年来火山气体排放的增加。我们提出了不同的灭绝速度和机制，因为我们认识到两个独立的但地质上突然的陆地大灭绝，一个在260.4 Ma结束中二叠纪（瓜达鲁普期），另一个在251 Ma结束二叠纪。我们的证据来自南极Portal山的古植物学、古植物学和碳同位素研究，以及南非Karoo盆地的类似研究。在瓜达鲁普纪末和二叠纪末，海洋无脊椎动物的灭绝一直很明显，这两个时期也是暖湿温室气候的过渡时期，土壤侵蚀明显，从高曲度到低曲度和辫状溪流的转变，湿地土壤停滞，以及严重的负碳同位素异常。这两次大灭绝都可能是由于煤被输水堤坝侵入到洪水玄武岩（如瓜达鲁普末期的峨眉山玄武岩和二叠纪末期的西伯利亚圈闭）中，向大气中灾难性地喷出甲烷造成的。
The end-Permian mass extinction has been envisaged as the nadir of biodiversity decline due to increasing volcanic gas emissions over some 9 million years. We propose a different tempo and mechanism of extinction because we recognize two separate but geologically abrupt mass extinctions on land, one terminating the Middle Permian (Guadalupian) at 260.4 Ma and a later one ending the Permian Period at 251 Ma. Our evidence comes from new paleobotanical, paleopedological, and carbon isotopic studies of Portal Mountain, Antarctica, and comparable studies in the Karoo Basin, South Africa. Extinctions have long been apparent among marine invertebrates at both the end of the Guadalupian and end of the Permian, which were also times of warm-wet greenhouse climatic transients, marked soil erosion, transition from high- to low-sinuosity and braided streams, soil stagnation in wetlands, and profound negative carbon isotope anomalies. Both mass extinctions may have resulted from catastrophic methane outbursts to the atmosphere from coal intruded by feeder dikes to flood basalts, such as the end-Guadalupian Emeishan Basalt and end-Permian Siberian Traps.