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二叠纪—三叠纪之交,湖北崇阳地区处于浅水碳酸盐岩台地环境。二叠纪末的全球事件在该剖面的沉积微相和生物演化上均留下了清楚的记录。二叠纪末生物大灭绝之前,崇阳地区为典型的正常浅海台地环境,生物种类多样,数量丰富,主要生物化石有钙藻、有孔虫、腕足、棘皮类和海绵等。生物大灭绝之后,钙藻、类、棘皮类、海绵、绝大部分有孔虫开始消失,取而代之的是个体微小的腹足、介形虫和大量的蓝细菌化石。大灭绝界线之上,首先出现的是25cm厚的纹层状的微生物岩,含较丰富的种类单调的有孔虫化石。之后逐渐相变为花斑状微生物岩和穹隆状微生物岩,厚度分别为6.4,2.3m。不同类型微生物岩在结构构造和生物组成上存在差别。微生物岩沉积结束之后,则相变为浅滩相鲕粒灰岩。共划分出3种沉积相,即开阔台地相、潮坪相和浅滩相。崇阳剖面的生物灭绝和沉积微相变化是二叠纪—三叠纪之交浅水台地环境生物与环境过程的典型代表,为认识二叠纪末浅海沉积相演化和全球事件提供了新材料。
Permian - Triassic dating, Hubei Chongyang region in shallow carbonate platform environment. Late Permian global events left clear records of sedimentary microfacies and biological evolution in this section. Prior to the Permian end-extinction, the Chongyang region was a typical normal shallow-sea platform environment with diverse and abundant biological species. The major fossils were calcareous algae, foraminifera, brachioptera, echinoderms and sponges. After the mass extinction, calcareous algae, echinoderms, sponges, most of the foraminifera began to disappear, replaced by individual tiny gastropods, ostracods and a large number of cyanobacteria fossils. Above the mass extinction line, the first appearance is a 25cm-thick laminar microbial rock, which is rich in monotonous foraminiferal fossils. After that, it gradually transformed into a porphyritic microbial rock and a dome-shaped microbial rock with thicknesses of 6.4 and 2.3 m respectively. Different types of microbial rocks in the structure and composition of biological differences. Microbial rock deposition after the end of the phase change to the shoal facies oolite limestone. A total of three types of sedimentary facies, that is, open platform facies, tidal flat and shallow facies. The biological extinction and sedimentary microfacies change of Chongyang section are typical representatives of the environmental biological and environmental processes of the Permian-Triassic Shallow Water Platform, and provide new materials for understanding the evolution and global events of the Late Permian marine sedimentary facies.