西南地区早—中二叠世玥类复合标准序列的建立及初步研究

A PRELIMINARY STUDY OF THE COMPOSITE STANDARD SEQUENCE OF THE EARLY—MIDDLE PERMIAN FUSULINACEANS OF SW CHINA

利用西南地区 10条石炭系—二叠系剖面上的类分布建立了该地区早—中二叠世类复合标准序列( CSS) ,总结了类 6 8属 6 32种在该地区的分布延限。根据类物种在复合标准序列上的分布规律 ,阐述了这一时期类动物群物种分异度的变化过程。研究结果表明 ,西南地区类物种分异度在早—中二叠世变化显著 ,共经历过三次快速增长时期 ,分别与假希瓦格亚科、米斯亚科及新希瓦格科的辐射演化有关 ;而物种分异度的两次大幅度下降则分别反映了早二叠世的动物群更替事件及中二叠世集群灭绝事件对本地区类动物的影响。

Based on fusulinid data from 10 well studied Carboniferous and Permian sections, a composite standard sequence (CSS) has been established for the Early— Middle Permian Fusulinaceans of SW China. The CSS, which summarized the regional stratigraphic distribution of 632 fusulinid species belonging to 68 genera, provided a valuable database to study the process of diversity change of the fusulinacean fauna in SW China throughout the Early to Middle Permian. Preliminary analyses of the CSS have revealed that the fusulinacean fauna in SW China exhibited 3 pulses of increase in species diversity, which were related respectively to the evolutionary radiation of the Pseudoschwagerininae, Miselliniae and Neoschwagerinidae. Analyses also suggested that the two apparent declines in species diversity of fusulinacean fauna were related to the Early Permian fauna turnover and the Middle Permian extinction event.