【摘要】 晚二叠世时,湖北赤壁位于扬子台地与北部硅质岩盆地的过渡地带.特殊的古地理位置,使该地区发育一套独特的地层沉积序列.沉积微相、古生物化石和草莓状黄铁矿的综合研究表明,晚二叠世长兴期至早三叠世早期,赤壁剖面沉积环境演化可分为6个阶段:近氧化的深水台缘硅质岩沉积、含氧量正常的台缘缓坡沉积、火山活动加剧而含氧量正常的台缘缓坡沉积、大灭绝后严重缺氧环境的沉积、大灭绝后贫氧环境下的沉积、大灭绝后氧化环境的沉积.由于赤壁剖面处在远离陆地的台缘缓坡环境,陆源剥蚀的影响可能比较有限,因此火山作用带来的营养物质可能是引起大灭绝后海洋缺氧的主要原因.更多还原

【Abstract】 The Chibi section of Hubei Province was located in the transitional zone between the Yangtze Platform and the northern deep silicious basin during Late Permian and its special paleogeographic setting led to the formation of a unique sedimentary sequence within the Permo-Triassic interval.Base on a comprehensive study of microfacies,fossils and pyrite framboids it is found that the evolution of the sedimentary environment of Chibi section can be divided into 6stages during the Later Permian Changhsingian to early stage of Early Triassic Period,which are nearly oxidized deepwater platform margin siliceous sedimentary,normoxic gentle slope platform margin sedimentary,volcanic activity intensified and normoxic platform margin gentle slope deposition,severe anoxic sedimentary environment,oxygen-depleted sedimentary environment and oxidizing environment of deposition after the mass extinction.The Chibi section was located in the gentle slope environment platform margin away from the land with limited impact from land-erosion,so nutrients from volcanism may be the main reason to cause marine anoxia aftermath the mass extinction.更多还原