冈底斯中段格达地区典中组火山岩锆石U-Pb年龄和地球化学特征  

Zircon U-Pb age and geochemical characteristics of the volcanic rocks in the Dianzhong Formation of the Geda area in the middle of the Gangdise

作　　者：周鹏 荣峰 周连河 刘恭喜 范源 万忠焱 尼玛洛卓 ZHOU Peng;RONG Feng;ZHOU Lianhe;LIU Gongxi;FAN Yuan;Wan Zhongyan;NIMA Luozhuo(Geothermal and Geological Party, Tibet Burseau of Mineral Resource Exploration and Development, Tibet Lhasa 850000,China)

机构地区：[1]西藏自治区地质矿产勘查开发局地热地质大队,西藏拉萨850000

出　　处：《中国地质调查》2022年第3期76-86,共11页Geological Survey of China

基　　金：中国地质调查局“冈底斯—喜马拉雅铜矿资源基地调查(编号:DD20160015)”项目资助。

摘　　要：青藏高原南部广泛发育的林子宗火山岩蕴涵着新特提斯洋俯冲与印度—亚洲大陆碰撞过程的地质信息。为探讨冈底斯中段格达地区典中组火山岩的形成时代、岩浆源区及构造环境等特征,对其开展了LA-ICP-MS锆石U-Pb同位素测年和地球化学特征研究。研究结果表明该地区典中组火山岩锆石U-Pb年龄为(61.6±1.0)Ma;典中组火山岩相对富集LILE和LREE、亏损HFSE,具典型岛弧火山岩的特征;岩浆源区主要来源于地壳物质部分熔融,是俯冲岛弧构造环境下新特提斯洋北向俯冲消减过程的产物。The Linzizong Group volcanic rocks are widespread in the southern part of the Qinghai-Tibet Plateau and the geological information of the Neo-Tethys subduction and the collision of Indian-Asian plate was recorded in those volcanic rocks.The LA-ICP-MS U-Pb isotope dating of zircon and geochemical characteristics of whole rocks were studied to investigate the formation age,magma source and tectonic environment in the Dianzhong Formation of the Geda area in middle of the Gangdise.The ages of LA-ICP-MS U-Pb dating of zircon from the volcanic rocks of Dianzhong Formation is(61.6±1.0)Ma.These volcanic rocks are charactered by rich LILE and LREE,and poor HFSE,with typical island arc characteristic.These volcanic rocks were mainly derived from the partial melting of crustal material,which were the formed in an island arc environment during the northward subduction of the Neo-Tethys ocean.

关 键 词：格达地区 典中组 锆石U-PB年龄 地球化学特征 

分 类 号：P588.124[天文地球—岩石学] P597.3[天文地球—地质学]