西藏双湖托拉木地区侏罗系索瓦组地层古生物

Stratigraphy and palaeontology of the Jurassic Suowa Formation in Tuolamu of Shuanghu,Tibet,China

在剖面测制基础上,讨论了北羌塘盆地南部双湖托拉木地区侏罗系索瓦组的岩性组合特征和沉积环境,将索瓦组细分为四个岩性段。根据实测剖面古生物化石的地层分布及组合特征,新建两个生物组合带,即双壳Myopholas multicostata-Protocardia stricklandi-Chlamys(Radulopecten)vagans组合带和珊瑚Stylomilia michelini-Pseudocoenia hexaphyllia组合带。根据生物组合带的时限及区域地层对比,将索瓦组归于上侏罗统,大致相当于牛津阶-基默里奇阶。

This paper discusses the characteristics of the lithologic associations and sedimentary environment of the Jurassic Suowa Formation in Tuolamu of Shuanghu located at the south of Northern Qiangtang Basin based on the measured section. The Suowa Formation is divided into four members for the first time in this area. Two biostratigraphic assembelage zones have been established according to fossil assembelages and their statigraphic ranges in the Suowa Formation, that is, the Myopholas multicostata-Protocardia stricklandi-Chlamys （Radulopecten） vagans assembelage zone and Stylornilia michelini-Pseudocoenia hexaphyllia assembelage zone. The Suowa Formation is assigned to the Upper Jurassic corresponding to Oxfordian-Kimmeridgian based on the biostratigraphic assembelage zones and area stratigraphic correlation.