华南乐平统放射虫生物地层学研究进展

PROGRESS IN LOPINGIAN RADIOLARIAN BIOSTRATIGRAPHY OF SOUTH CHINA

以Albaillella分子的地层分布为基础,华南地区晚二叠世地层中已经建立5个放射虫化石带,自下而上分别为:Albaillella cavitata带、Albaillella levis带、Albaillella excelsa带、Albaillella triangularis带和Albail-lella yaoi带。Albaillella cavitata带地层范围相当于牙形石Clarkina postbitteri postbitteri带至Clarkina guang-yuanensis带的底部,其下伏放射虫化石Follicucullus bipartitus-Follicucullus charveti带的地质时代为中二叠世。Albaillella triangularis带层位相当于牙形石Clarkina post wangi带,Albaillella yaoi带与牙形石Clarkina yini带相当。华南晚二叠世放射虫动物群演化明显分为两个阶段:第一个繁盛期始于中二叠统上部,延续到A.cavita-ta带下部,以Follicucullus的丰富和多样化为特征;第二个繁盛期出现在A.levis带至A.yaoi带之间,以Albail-lella和Neoalbaillella的鼎盛为特征。

Five Upper Permian（Lopingian） radiolarian biozones have been set up in South China on the basis of the stratigraphic distributions of the Albaillella elements,including Albaillella cavitata Zone,Albaillella levis Zone,Albaillella excelsa Zone,Albaillella triangularis Zone,and Albaillella yaoi Zone.The Albaillella cavitata Zone is correlative with the stratigraphic interval from Clarkina postbitteri postbitteri Zone（conodonts） to the lower part of the Clarkina guangyuanensis Zone（conodonts）.The Follicucullus bipartitus-Follicucullus charveti Zone,below the Albaillella cavitata Zone,is assigned to the upper part of Middle Permian（Guadalupian）.The Albaillella triangularis Zone is corresponding with the Clarkina postwangi Zone（conodonts） and the Albaillella yaoi Zone with the Clarkina yini Zone（conodonts）.There are two booming stages for the Upper Permian radiolarian fauna in South China：the first stage begins from the uppermost Middle Permian to lower A.cavitata Zone,characterized by abundant and diverse Follicucullus;the second stage coincides with the stratigraphic interval from the Albaillella levis Zone to the Albaillella yaoi Zone,which is characterized by abundant Albaillella and Neoalbaillella.