西藏聂荣微陆块奥陶纪和侏罗纪岩浆事件的年龄证据  

Geochronological Evidence of Ordovician and Jurassic Magmatic Events in Nyainrong Microcontinent,Tibet

作　　者：陆露[1,2] 钱程 赵珍[4] 吴珍汉[4] 刘玉双[1,2] 周亮[5] 王岩 Lu Lu1,2 , Qian Cheng3, Zhao Zhen4 , Wu Zhenhan4 , Liu Yushuang1,2 , Zhou Liang5, Wang Yan1(1.Paleontological College, Shenyang Normal University ,Shenyang 110034,China; 2.Key Laboratory of Evolution of Past Life in Northeast Asia ,Ministry of Land and Resources ,Shenyang 110034,China; 3.Shenyang Institute of Geology and Mineral Resources,Shenyang 110000,China; 4.Chinese Academy of Geological Sciences ,Beijing 100081,China; 5.College of Earth Science and Engineering ,Shandong University of Science and Technology ,Qingdao 266590,Chin)

机构地区：[1]沈阳师范大学古生物学院,辽宁沈阳110034 [2]国土资源部东北亚古生物演化重点实验室,辽宁沈阳110034 [3]沈阳地质矿产研究所,辽宁沈阳110000 [4]中国地质科学院,北京100081 [5]山东科技大学地球科学与工程学院,山东青岛266590

出　　处：《地球科学》2018年第4期1110-1124,共15页Earth Science

基　　金：国家自然科学基金面上项目(No.31672332);中国地质调查局项目(No.DD20160161);沈阳师范大学博士;引进人才科研项目启动基金项目(No.BS201705)

摘　　要：为了加深对班公湖-怒江缝合带构造演化过程的认识,选择聂荣微陆块内的花岗质片麻岩和花岗闪长质片麻岩中的锆石进行LA-ICP-MS U-Pb定年,结果主要显示两组206 Pb/238 U的加权平均年龄:一组为453.7±2.5Ma;另一组为176.6±1.1Ma和178.04±0.8Ma.花岗质片麻岩中黑云母和花岗闪长质片麻岩中白云母的40 Ar-39 Ar定年结果显示,坪年龄分别为161.8±1.1Ma和178.9±1.2Ma.上述年龄结果表明,聂荣微陆块主要经历了晚奥陶世和早侏罗世两期岩浆事件,这两期岩浆事件分别与冈瓦纳大陆北缘早古生代的造山作用和班公湖-怒江洋壳的俯冲闭合存在密切的动力学关系.In order to deepen our knowledge and understanding about the tectonic evolution of the Bangonghu-Nujiang suture zone（BNS）,zircon U-Pb dating was conducted for granitic gneiss and granodioritic gneiss of Nyainrong microcontinent by LAICP-MS in this study.Results show two groups of average zircon U-Pb ages,with one of 453.7±2.5 Ma,and the other of176.6±1.1 Ma and 178.04±0.8 Ma.^40Ar-^39Ar dating was conducted for biotite from granitic gneiss and muscovite from granodioritic gneiss in Nyainrong microcontinent.The ^40Ar-^39Ar plateau ages yield 161.8±1.1 Ma and 178.9±1.2 Ma,respectively,showing that the study area experienced the Late Ordovician and the Early Jurassic magmatic events.Combined with field condition and study results,it is suggested that the Ordovician magmatic event was related to the Early Paleozoic orogeny which could be caused by proto-Tethyan oceanic subduction along Gondwana continental margin,and the Jurassic magmatic event was related to the subduction and closure of the Bangong-Nujiang oceanic crust.

关 键 词：青藏高原 聂荣微陆块 锆石U-Pb年龄 ^40AR-^39AR年龄 班公湖-怒江缝合带 地质年代学 

分 类 号：P56[天文地球—构造地质学]