塔里木盆地中部辉绿岩脉LA-ICP-MS锆石U-Pb年龄及其地质意义

摘要

Seismic data obtained from the central Tarim Basin show that lots of diabase dykes are developed in Cambrian,Ordovician and Permian strata.Diabase dykes that invaded into Silurian and Ordovician strata were collected near the fault zone (Zhong 1 well,Zhong 16 well core).Using LA-ICP-MS determination technology,the authors determined U-Pb age and trace elements in zircon.Zircon U-Pb age shows that the diabase dykes were formed in the Early Permian period of 273～296Ma.Measured 700～930Ma (Late Proterozoic) and 396～544Ma (Paleozoic) show the tectonic-magmatic activity when basin was formed.121.0±8.5Ma (Early Cretaceous) zircon indicates that the formation was related to hydrothermal activities in the same period.%塔里木盆地塔中地区地震资料显示,寒武系、奥陶系、二叠系中发育大量辉绿岩岩脉,在塔中隆起断裂带附近采集了侵入到志留系与奥陶系中的辉绿岩脉样品(中1井、中16井岩心).用LA-ICP-MS测定技术,测定了其中锆石的U-Pb年龄和微量元素.锆石U-Pb年龄显示,这些辉绿岩岩脉形成于早二叠世(273～296Ma);测得的700～930Ma(新元古代)、396～544Ma(古生代)年龄显示,盆地早期有构造岩浆活动;121.0±8.5Ma(早白垩世)锆石存在,显示其形成与盆地内部同期热液活动有关.