塔河南上奥陶统桑塔木组沉积环境分析

Sedimentary environment analysis of Sangtamu Formation of Upper Ordovician in the south of Tarim River,Xinjiang,China

对塔河南20余口钻井进行了详细的岩性观察和室内薄片鉴定,在测井相和地震相识别的基础上,确定了研究区桑塔木组的岩石学特征、古生物组合特征及地层分布特征,进而分析得出其为台地前缘斜坡和内陆棚沉积环境。其中台地前缘斜坡以深灰、灰绿色钙质泥岩、粉砂岩、砂岩为背景夹肥肠状的灰岩“砾”为特征。内陆棚以深灰、灰绿色灰质泥岩夹浅灰色砂质、灰质纹层或条带为特征,并编制了该地区桑塔木组的岩相古地理图。

Based on the study of twenty eight cores and thin section observations from the Sangtamu Formation in the south of Tarim River, this paper determines the petrologic features, fossil assemblages and facies distribution with the helps of ray logging and seismic data. The authors divide the Sangtamu Formation into the platform foreslope and inner shelf sedimentary environments. The platform foreslope is composed of the dark grey and celadon calcareous mudstone, siltstone, sandstone intercalated with limestone conglomerate, and the inner shelf is characterized by the dark grey and celadon calcareous mudstone intercalated with slight grey arenaceous, calcareous veins and stripes. At last, the authors describe the distribution of the depositional facies in space.