东昆仑祁漫塔格地区白垩纪基性岩墙的发现及其意义

Lithogeochemical Characteristics of Cretaceous Basic Dyke Swarm from Qimantag Region in East Kunlun and Its Geological Significance

摘要: 对东昆仑祁漫塔格地区首次发现的辉绿岩墙群进行了初步的研究，辉绿岩为高TiO₂（1.65%~2.87%）、高碱（全碱在2.98%~5.32%）的碱性玄武岩系列岩石，辉绿岩中采用LA-ICP-MS锆石U-Pb测年获得了102 Ma的年龄，Sm-Nd等时线年龄为（120±8.3） Ma，从而确定了东昆仑祁漫塔格地区白垩纪基性岩墙群的存在，并可初步确定东昆仑祁漫塔格地区早白垩世处于伸展构造环境。

Abstract: The firstly discovered diabase dykes swarm in Qimantag region of East Kunlun has high TiO₂ (1.65%~2.87%) and alkali (2.98%~5.32%) contents, belonging to alkalic basalt series. LA-MC-ICP-MS zircon U-Pb dating of diabase dyke (porphyrite) has obtained an age of 102 Ma, while its Sm-Nd isochron age is (120±8.3)Ma. Therefore, it's confirmed that the early Cretaceous diabase dike is existed in Qimantag region, East Kunlun,and the area had entered the intracontinental extension stage in early Cretaceous.