新疆库鲁克塔格北部现代河流沉积物源分析:碎屑锆石U-Pb年代学的证据  

Source analysis of modern river sediments in the northern Quruqtagh area,Xinjiang:Evidence from the detrital zircon U-Pb dating

作　　者：郭瑞清 崔涛 刘桂萍 宫相宽 宋志豪 GUO Rui-qing;CUI Tao;LIU Gui-ping;GONG Xiang-kuan;SONG Zhi-hao(Xinjiang Key Laboratory of Geodynamic Processes and Metallogenic Prognosis of the Central Asian Orogenic Belt,College of Geology and Mining Engineering,Xinjiang University,Urumqi 830046,China)

机构地区：[1]新疆大学地质与矿业工程学院新疆中亚造山带大陆动力学与成矿预测自治区重点实验室,新疆乌鲁木齐830046

出　　处：《矿物学报》2020年第6期747-757,共11页Acta Mineralogica Sinica

基　　金：自治区研究生科研创新项目(编号:XJ2019G059);国家自然科学基金项目(编号:41762015);大学生创新训练计划项目(编号:201910755031,S201910755023)。

摘　　要：古生代时期塔里木北缘是否为主动大陆边缘对于了解南天山洋俯冲方式及塔里木北缘地质演化具有极其重要的意义。本文对取自乌斯腾高勒河沟的69粒碎屑锆石进行阴极发光和LA-ICP-MSU-Pb定年,获得的50组U-Pb有效年龄数据表明:1)物源主要集中在库鲁克塔格北部379~466 Ma、651~817 Ma及1844~2122 Ma的岩石;2)碎屑锆石U-Pb有效年龄记录了至少3期构造热事件,其中,锆石年龄379~466 Ma的碎屑锆石表明,在古生代中期库鲁克塔格地区发育大规模岩浆作用,经对比研究发现,这些事件可能与该期南天山洋向南俯冲,塔里木北缘为主动大陆边缘有关,晚元古代的岩浆作用可能记录了罗迪尼亚超大陆裂解事件,早元古代变质锆石的存在可能与哥伦比亚超大陆有关。Whether the northern margin of Tarim plate was an active continental margin in Paleozoic is of great importance for understanding the subduction mode of the South Tianshan ocean and the geological evolution of the northern margin of Tarim plate.In this paper,69 grains of detrital zircons collected from the Wusitenggaole river in the northern Quruqtagh area have been examined by using cathodoluminescent imaging method and dated by using LA-ICP-MS U-Pb dating method.The obtained data of 50 groups of U-Pb effective ages show that:(1)The provenances of river sediments are mainly concentrated into 379-466 Ma,651-651 Ma,and 817-2122 Ma aged rocks in the northern Quruqtagh area.(2)The effective U-Pb ages of detrital zircons have revealed there were at least 3 tectonic thermal events.Especially,ages ranging from 379 to 466 Ma of detrital zircons indicate that there were large scale magmatisms in the Quruqtagh area in the middle Paleozoic.It is found by comparative study that those Middle Paleozoic magmatic events could be related to the southward subduction of the South Tianshan ocean and the active continental margin of the northern margin of the Tarim plate.The Neoproterozoic magmatism may be a record of the Rodinia supercontinent cracking event.The existence of Paleoproterozoic metamorphic zircons may be related to tectonic events of the Colombia supercontinent.

关 键 词：水系沉积物 碎屑锆石U-Pb定年 物源分析 库鲁克塔格 塔里木北缘 

分 类 号：P597[天文地球—地球化学]