【摘要】 利用X射线衍射、扫描电镜、能谱等鉴定分析方法,对湖北兴山大峡口剖面二叠系—三叠系界线附近的8层粘土岩研究发现,各层粘土岩中的主要粘土矿物均为伊/蒙混层矿物,并且各层中均含有数量不等的六方双锥石英和黄铁矿,非粘土矿物为石膏,个别层位中还含有粘土微球粒。该8层粘土岩均为火山物源成因,联系相应的火山事件记录表明该地区在二叠系—三叠系之交经历了多次火山活动。这些火山事件与同时段牙形石的绝灭和延缓复苏呈现一致性。频繁的火山活动是造成二叠纪—三叠纪之交生物及生态系重大转折的主导事件之一。更多还原

【Abstract】 Such instruments as D/max-3B mineral powder diffractometer,Quanta-200 environmental scanning electron microscope and energy dispersive spectrometer were used to study the mudstones around the Permian-Triassic boundary at the Daxiakou Section,Xingshan,Hubei Province,China.It is showed that all the mudstones were characterized by predominant illite-montmorillonite mixed-layer(I/M) minerals,with different amount of high-temperature hexagonal bipyramid(HB) quartzes and pyrites.Micro-spheres clay occurred occasionally in some beds.Detailed study revealed that volcanic activity was once frequent in the area or in the neighboring areas during the Permian-Triassic transition though the intensity of eruption and the position of eruption centers might vary during that period.The volcanic activity was considered to be one of the leading events to cause the momentous turnover of biota and ecosystem during the great Permian-Triassic transition.更多还原