藏东玉龙斑岩铜矿带扎拉尕含矿斑岩体锆石U-Pb年龄及其地质意义  

Zircon LA-ICP-MS U-Pb age of the Zalaga porphyry associated with Cu-Mo mineralization in the Yulong ore belt and its geological implication

作　　者：何国朝[1,2] 王广强[2,3] 黄文婷[2,3] 邹银桥[2,3] 伍静[2] 梁华英[2] 张玉泉[2] Charllote M ALLEN 

机构地区：[1]广西有色金属集团资源勘查有限公司,广西南宁530022 [2]中国科学院广州地球化学研究所中国科学院矿物学与成矿学重点实验室,广东广州510640 [3]中国科学院大学,北京100049 [4]Research School of Earth Sciences, Australian National University

出　　处：《地球化学》2014年第4期399-407,共9页Geochimica

基　　金：中国科学院战略性先导科技专项(B类)(XDB03010302);国家自然科学基金(41272099;41121002)

摘　　要：玉龙斑岩铜矿带扎拉尕斑岩铜钼矿床位于玉龙斑岩铜矿带中北部,赋矿岩体侵入下二叠统火山岩及三叠系砂泥岩中,主要由早阶段为二长花岗斑岩及晚阶段正长花岗斑岩组成。分析了早阶段二长花岗斑岩及晚阶段正长花岗斑岩锆石LA-ICP-MS U-Pb年龄。早阶段二长花岗斑岩该年龄为(38.5±0.2)Ma,MSWD=1.12,晚阶段正长花岗斑岩该年龄为(38.5±0.2)Ma,MSWD=1.08,早阶段和晚阶段含矿斑岩体锆石U-Pb年龄完全一致。这表明早晚两阶段成矿岩体是在很短的时间间隔内形成的。扎拉尕赋矿斑岩体形成年龄为(38.5±0.2)Ma。据扎拉尕斑岩矿床形成时代及藏东地区在始新世至渐新世地质构造背景,提出扎拉尕斑岩矿床和玉龙斑岩铜矿带的形成与印度板块-欧亚板块碰撞在藏东地区形成的走滑构造活动诱发的岩浆活动有关,为陆陆碰撞走滑构造环境的斑岩矿床。The Zalaga porphyry Cu-Mo deposit is located at the northern domain of the Yulong porphyry copper ore belt in the eastern Tibet. The porphyry emplaced into the lower Permian volcanic rock and Late Triassic sandstone and could be divided into early stage monzonite granite porphyry and late stage syenogranite porphyry. Both stages of the porphyry were dated, respectively, using zircon LA-ICP-MS U-Pb method. The early stage monzonite granite porphyry has zircon LA-ICP-MS U-Pb age of （38.5±0.2） Ma, MSWD=1.12 and the late stage syenogranite porphyry has zircon LA-ICP-MS U-Pb age of （38.5±0.2） Ma, MSWD=1.08. The early porphyry has the same zircon LA-ICP-MS U-Pb age as that of the late stage porphyry, suggesting that the early porphyry and late stage porphyry emplaced almost at the same time and that the Zalaga porphyry was emplaced during the Late Eocene. Based on the structural condition of the period during Eocene to Oligocene in eastern Tibet, it is concluded that the Zalaga porphyry Cu-Mo（Au） deposit and the Yulong porphyry copper ore belt has genetic relation to the activities of strike-slip fault zone which transverses the lithosphere mantle and triggered the magmatic activities caused by the collision between Indian and Asia continents.

关 键 词：斑岩铜钼矿床 成岩成矿时代 碰撞与成矿 西藏东部 

分 类 号：P597[天文地球—地球化学]