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基金项目:中国地质调查局项目“江南造山带东段新元古代沟弧盆体系演化与大陆生长研究”
作者单位
钱迈平,马雪,姜杨,等 南京地质矿产研究所 
摘要:
      中国西南部三叠纪海相生物群主要有海生爬行类、鱼类、棘皮类、菊石类、双壳类、腹足类及节肢动物等,分布范围包括贵州关岭、兴义、盘县和云南罗平一带的中—上三叠统关岭组、竹竿坡组及小凹组灰黑色钙质泥岩及泥质灰岩地层。这些生物群高度分异,数量丰富,反映了地球生命在经历了二叠纪末大绝灭以及早三叠世的相对停滞期后,在中三叠世开始进入迅速辐射演化的新阶段。这样不同类型和不同生长阶段的大量海洋动物同时集群死亡,并被迅速封埋保存成化石,反映了当时多次发生突发灾变事件。这与该生物群所处的古地理位置恰好位于华南板块、江南造山带及印度支那板块交界区构造活动带的海湾盆地环境有密切关系。推测那里滞流深水区还原环境形成硫化氢水团,在印支造山运动期间多次发生的海底地震及火山活动时,其硫化氢水团及海底富含碳酸盐的软泥泛起,混合成高密度有毒浊水团,侵入海洋生物群生存的清澈浅水区,导致大量海洋生物中毒窒息,出现突发性集群死亡,随后又被有毒浊水团携带的泥沙迅速封埋,在以后的成岩作用中保存为灰黑色钙质泥岩及泥质灰岩中的精美化石。
关键词:三叠纪  海相生物群  集群死亡  贵州  云南
Abstract:
      The Triassic marine biota in southwestern China mainly include reptiles, fishes, echinoderms, ammonoids, bivalves, gastropods and arthropods, and their fossils are distributed in grey black calcareous mudstone and argillaceous limestone beds of the Middle-Upper Triassic Guanling Formation, Zhuganpo Formation and Xiaoao Formation in Guanling, Xingyi, Panxian counties of Guizhou Province and Luoping County of Yunnan Province. The great disparity and abundance of the biota suggest that creatures on the Earth started to enter a new stage of rapid evolutionary radiation in the Middle Triassic after the end-Permian mass extinction and the early Triassic relative stagnation stage. These various kinds and growth stages of marine creatures experienced mass mortalities at almost the same time, and were immediately buried and preserved as fossils, which indicates repeated sudden catastrophic events during that time. This may be closely related to the geographic location of the biota, i.e., in a bay basin at the actively tectonic boundaries of the South China Block, Jiangnan Orogenic Belt and the Indochina Block. The repeated submarine earthquakes and volcanic activities during the Indosinian orogeny resulted in the formation of hydrogen sulfide in deep water reducing environments in the basin. The hydrogen sulfide and carbonate-rich seabed ooze moved together upward to mix into high-density turbid water, and invaded the clear shallow-water oxidizing environment where the biota lived, causing sudden mass mortalities of marine creatures from poisoning and suffocation. Subsequently, their remains were rapidly buried by silt carried by the toxic water, and formed superbly preserved fossils in grey black calcareous mudstone and argillaceous limestone beds in later diagenesis.
Keywords:Triassic  marine biota  mass mortality  Guizhou  Yunnan
钱迈平,马雪,姜杨,等.中国西南部三叠纪海相生物群及其集群死亡事件[J].地质学刊,2015,39(4):519-529