新疆库米什地区晚志留世地层划分及沉积环境初步探讨

作者运用生物地层学、岩石地层学及同位素年代学资料,重新厘定了库米什地区晚志留世地层层序,进一步确定阿尔皮什麦布拉克组时代属晚志留世。在恢复原岩的基础上,分析其沉积环境,属岛弧或活动陆缘。晚志留世早期沉积为有障壁的浅水陆棚及海滩环境,中期为台地前斜坡,并形成碳酸盐岩台地边缘生物礁,晚期则是陆表海浑水有障壁环境及浅海开阔陆棚。

A PRELIMINARY ANALYSIS ON THE SUBDIVISION AND SEDIMENTARY ENVIRONMENT OF LATE SILURIAN IN KUMISHI XINJIANG

In this paper, the authors apply the data of lithostratigraphy, biostratigraphy and isotope chronology to collating and stipulating the sequence of the late Silurian again, and to the further definition of the age of the Aerpishmaibulake formation .The age of that formation has been incorpra-ted now into the late Silurian. On the basis of the reconstruct of the characteristics of the primitive rocks this paper makes a preliminary analysis of its sedimentary environments. The petrological characteristics of the sandstone and amphibolite show that they belong to the sidimentary island arc or the mobile continental margin. Sedimentary environments at the early stage of the late Silurian were sallow sea facies with barrier and seabeach; the middle stage was the slope before platforms, thus forming the bioherm at the carbonatite margin- those at the late stage are the, muddy epiconti-nental sea with the barrier and the widely epicontinented neritic facies.