塔里木柯坪地区下志留统碎屑锆石U-Pb年代学特征及其地质意义  

U-Pb Dating of Detrital Zircon from Lower Silurian in Keping Area of Tarim Basin and Its Geological Implication

作　　者：常健[1,2] 邱楠生[1,2] 李佳蔚[1,2] 

机构地区：[1]中国石油大学(北京)油气资源与探测国家重点实验室,北京102249 [2]中国石油大学(北京)盆地与油藏研究中心,北京102249

出　　处：《地球科学与环境学报》2012年第3期32-43,共12页Journal of Earth Sciences and Environment

基　　金：国家自然科学基金项目(41072103);中国石油大学(北京)油气资源与探测国家重点实验室开放基金项目(PRPJC2008-01)

摘　　要：柯坪地区物源及演化与塔里木盆地的古地理位置密切相关。通过对下志留统碎屑锆石的形态特征和U-Pb年龄分布特征进行分析,系统研究了柯坪地区下志留统的物源及其演化。结果表明:柯坪地区下志留统锆石均为岩浆锆石,锆石U-Pb年龄反映的是成岩年龄或结晶年龄,可有效指示物源区;下志留统柯坪塔格组的物源区主要为沙雅隆起西部、塔中隆起及塔西南前缘隆起,之后受海侵的影响,塔中隆起被海水淹没,下志留统塔塔埃尔塔格组的物源区演变为沙雅隆起西部、塔西南前缘隆起及塔中隆起的南部于田、康西瓦地区;满加尔凹陷的存在使得柯坪地区与塔中、塔东地区的物源具有很大的差异;900～700Ma的锆石年龄谱表明,塔里木地块与冈瓦纳大陆具有一定的亲缘关系。The provenance and evolution in Keping Area are closely correlated with the paleogeography of Tarim Basin. The morphology of detrital zircon and distribution characteristics of U-Pb age in Lower Silurian were analyzed, and the provenance and evolution from Lower Silurian in Keping Area were systematically studied. The results showed that the zircons from Lower Silurian in Keping Area were magmatic, zircon U-Pb age represented diagenesis age or crystallinic age and effectively indicated the provenance; the provenances in Kalpintag Formation of Lower Silurian were mainly western Shaya Uplift, Tazhong Uplift and the frontal uplift in the southwestern of Tarim Basin, and then Tazhong Uplift was covered by seawater due to the transgression, the provenances in Tataaiertag Formation of Lower Silurian became the western Shaya Uplift, the frontal uplift in the southwestern of Tarim Basin and the Yutian and Kangxiwa Areas in the southern of Tazhong Uplift; the provenance in Keping Area was different with that in the central and eastern of Tarim Basin because of Manjiaer Sag; the zircon ages of 900 700 Ma illustrated that Tarim Block was related to Gondwanaland.

关 键 词：碎屑锆石 U-Pb定年 志留纪 物源 沙雅隆起 塔中隆起 柯坪地区 塔里木盆地 

分 类 号：P597.3[天文地球—地球化学]