羌塘盆地北部马料山侏罗纪布曲组地层古生物及沉积环境

Stratigraphy,paleontology,and sedimentary environment of the Jurassic Biqu Formation at Maliao Mountain,northern Qiangtang basin

详细描述了羌塘盆地北部乌兰乌拉湖地区马料山侏罗系剖面,将剖面划分为雀莫错组、布曲组和夏里组3个岩石地层单位,其中布曲组出露齐全,化石丰富。根据沉积环境及相对海平面变化规律将布曲组划分为2个沉积层序,并讨论了各体系域特征。依据马料山剖面布曲组的生物组合及分布特征建立了1个双壳类生物组合带即Chlamystipperi-Protocardiastricklandi组合带,并细分为3个组合亚带,其时限为中侏罗世巴通期。

This paper describes in detail a Jurassic section at Maliao Mountain in the Ulan Ul Lake area,northern Qiangtang basin.The Jurassic strata of the section are divided into the Qoima Co ,Biqu,and Xiali Formations ,of which the Biqu Formation is completely exposed and contains abundant fossils.Ac-cording to the sedimentary environment and relative sea-level changes,the Biqu Formation is subdivided into two depositional sequences and the characteristics of various system tracts are discussed.According to the main biotic assemblages and distribution characteristics of the Biqu Formation at the Maliao Mountain section,a bivalve assemblage zone,i.e.the Chlamys tipperi-Protocardia stricklandi Assemblage Zone,is established,and three subzones are distinguished.Its time range is Middle Jurassic Bathonian.