湖南慈利康家坪剖面二叠纪末类有孔虫的灭绝过程

THE EXTINCTION PATTERN OF FUSULINIDS DURING THE PERMIAN-TRIASSIC CRISIS AT THE KANGJIAPING SECTION,CILI,HUNAN PROVINCE

湖南慈利地区二叠系-三叠系界线附近地层非常发育,是探讨二叠纪-三叠纪之交生态系转变的良好区域。本研究通过对该地区康家坪剖面长兴组上部与大冶组下部地层进行系统采样、切片研究,在长兴组上部地层中发现278个类有孔虫,共鉴定出4属11种(含2个未定种)。这些类有孔虫在地层中的分布表明类有孔虫在二叠纪末经历了一次突变式的灭绝过程,其灭绝层位位于长兴组顶部的生物碎屑灰岩与大冶组底部的微生物岩之交界线处。该研究不仅丰富了康家坪剖面在这一关键时期的生物群面貌,而且也为二叠纪末的生物灭绝事件的深入研究提供了新的材料。

The Permian-Triassic boundary strata in Cili County, Hunan Province reflect clearly marine ecosystem changes in the end-Permian catastrophe crisis. Twelve species （including two indeterminate species） in four genus of fusulinids were identified from the Changxing Formation at the Kangjiaping section based on systematic samples in the upper Changxing Formation and lower Daye Formation. The distribution of these 278 fusulinids in the Permian-Trias sic strata show that fusulinids experienced an abrupt extinction at the boundary between bioclastic limestone and calci microbialites. This abundant fusulinid fauna provides new data for a better understanding of the extinction event near the Permian Triassic boundary.