塔里木盆地东北部地区充填序列的物源分析

PROVENANCE ANALYSIS OF THE BASIN-DEPOSITED SEQUENCE IN THE NORTHEASTERN TARIM

塔里木盆地东北部志留、泥盆纪、中新生代充填序列的岩性，主要为硅质碎屑岩。作者采用点计法对该充填序列中的砂岩进行了骨架矿物统计分析，结合区域地质构造背景研究认为：库车拗陷的物源区为南天山造山带，沉降中心的充填序列，记录了南天山造山带的揭顶剥蚀史。志留一泥盆纪时，塔东北拗陷的物源区为北部古塔北隆起和加里东中期抬升的寒武－奥陶系和东北角的库鲁克塔格隆起；三叠－侏罗纪时，物质来源主要为海西运动时形成的沙雅隆起和库鲁克塔格隆起；自白垩纪以来，坳陷主要接受南天山造山带的物质。物源区的类型不仅随着坳陷的演化而变化，而且同一源区的物质也随其被搬运的距离增大而造成不同的砂岩矿物组成。

The basin-deposited sequence of Silruian,Devonian and Mesozoic-Cenozoic are mainly of siliceous clastics.The point-count method is applied to conduct statistical analysis of the framework minerals.Coupled with the regional geological structural settings,the study shows that the materials of Kuqa depression are derived from South Tianshan Orogeny,and that the sinking centre of basin-deposited sequnence records the history of erosion of South Tianshan Orogeny.Up to Silurian-Devonian the materials of Northeast Tarim depression are derived from the northeastern Palaeo-North Tarim uplift,the Cambrian-Ordovician uplift of middle Caledonian,and Kuruktag uplift of northeast angle.Up to Triassic-Jurassic,the materials come from Shaya uplift and Kuruktag uplift formed in the Haixi stage.From Cretaceous to present,the depression mainly receives the materials from South Tianshan Orogeny.The material source areas change with the evolution of the depression,and the materials from the same source area chanse with the transportation distance,resulting in the different sandstone mineral compositions.