四川蒲江地区上三叠统须家河组地层古生物特征及沉积环境

    Palaeontology characteristics and sedimentary environment of the Upper Triassic Xujiahe Formation in the Pujiang area, Sichuan, China. Geological Bulletin of China

    • 摘要: 对蒲江县熊坡背斜一带出露的上三叠统须家河组进行了实测和系统采样分析。根据古生物化石组合的特征将其划分为2个生物组合带:即Weiyuanella rhomboidallis-Permophorus emeiensis双壳组合带和Zamites jiangxieensis-Clathropteris植物组合带,结合岩性特征及层位对比, 认为该区仅出露有须家河组五段和六段。沉积相分析表明,须家河组的沉积环境为辫状河三角洲,并细分为三角洲平原亚相和三角洲前缘亚相。证实须家河组与上覆中侏罗统新田沟组为平行不整合接触,缺失下侏罗统

       

      Abstract: Survey and systematic sampling were conducted for Xujiahe Formation located at the anticline of Xiongpo in Pujiang County. According to paleontology fossil assemblage, two biological zones can be divided: namely Weiyuanella rhomboidallis-Permophorus emeiensis assemblage and Zamites jiangxieensis-Clathropteris assemblage. In combination of lithological and stratigraphic comparison, it is asserted that Xujiahe Formation of this area belongs to the fifth and sixth rock members. The sedimentary facies of Xujiahe Formation in this area is delta facies, which can be subdivided into two sub-facies namely delta plain and delta front. The conclusion has been verified the contact relationship between Xujiahe Formation and its overlying Middle Jurassic Xintiangou Formation is parallel unconformity, also Lower Jurassic series are missing.

       

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