四川广元上寺剖面长兴阶放射虫动物群演变及控制因素  

Evolution and Its Control Factors of the Changhsingian Radiolarian Fauna at the Shangsi Section in Jiange County,Guangyuan City,Sichuan Province

作　　者：聂小妹[1] 雷勇[1] 冯庆来[1] 向宇[1] 

机构地区：[1]中国地质大学地质过程与矿产资源国家重点实验室,武汉430074

出　　处：《地质论评》2012年第5期809-815,共7页Geological Review

基　　金：国家自然科学基金项目(编号40839903和40921062)"地质过程与矿产资源"国家重点实验室科技部专项经费共同资助的成果

摘　　要：对四川广元上寺剖面大隆组的放射虫动物群进行了详细的鉴定和丰度、分异度的统计。发现该放射虫动物群丰度和分异度均较低,以泡沫虫和内射虫为主,含少量十字多囊虫的分子;其丰度和分异度与长兴期海平面变化具有很好的耦合关系:放射虫丰度、分异度较大的层位对应于长兴早期和长兴晚期两次最大海侵事件发生的层位。相对长兴晚期而言,长兴早期放射虫的丰度和分异度较大,这与长兴早期水体相对较深有关。此外,有孔虫与放射虫丰度变化呈现很好的负相关性,这与它们不同的生活习性和水深的变化有关。分析表明:水深的变化是上寺剖面放射虫动物群演变的主要控制因素。A well-preserved Changshingian radiolarian fauna was obtained from bedded siliceous limestone and interbedded siliceous shale of the Dalong Formation in Shangsi area, Guangyuan, Sichuan, South China. The radiolarian species in each sample were identified, and the individuals in 1 g samples （ sieved through 300 meshes ） were counted out. In general, most of the encountered specimens are Spumellaria and Entactinaria. Neither the abundance nor the diversity of it is high. The research shows that the abundance and diversity are closely related to sea level changes of Changhsingian age at the Shangsi Section. Where abundance and diversity reached higher values, the sea level would have peaked （ marine flooding surfaces ）. The abundance and diversity of radiolarians from the early Changhsingian is greater than that of the late Changhsingian age, which coincides with the opinion that the marine water was deeper in the early Changhsingian than that in the late Changhsingian. Furthermore, foraminifer and radiolarian abundance showed a good negative correlation which may be caused by their different living habits and changes of water depth. Analysis shows that： the development of the Late Permian radiolarian fauna of the Shangsi Section, may result from changes of water depth.

关 键 词：放射虫 丰度 分异度 海平面变化 长兴期 上寺剖面 

分 类 号：Q915[天文地球—古生物学与地层学]