哈密沁城地区红柳沟组流纹岩LA-ICP-MS锆石U-Pb年代学及地质意义

摘要

天山东段古生代火山-沉积地层时代特别是变质事件的厘定对探讨天山古生代洋盆演化具有重要意义。本文首次对出露于哈密沁城地区的红柳沟组中的流纹岩进行了LA-ICP-MS锆石U-Pb测年，获得了锆石（U-Pb）年龄为（426±12）Ma（MSWD=0.31），该年龄可以代表红柳沟组的沉积年龄。同时，获得变质锆石的加权平均年龄为（372±28）Ma（MSWD=0.021），该期变质事件在天山普遍发育，可能与天山古生代洋盆碰撞有关。%Abstact:There is a significance to investigate Tianshan Paleozoic oceanic basin evolution by determining the age of the Paleozoic volcanic-sedimentary strata especially metamorphic events in Eastern Tianshan area.This article is the first time to date the rhyolite by LA-ICP-MS zircon U-Pb in Hongliugou formation in Qincheng area of Hami,indicates an age of (426±12) Ma(MSWD=0.31),This age represents the depositional age of Hongliugou formation. Meanwhile,indi-cates a metamorphic age of (372±28) Ma(MSWD=0.021).This development of metamorphic event is very common in Tianshan area,it could be related to Tianshan Paleozoic ocean basin collision.