西昆仑北缘奥依塔克-盖孜地区斜长花岗岩LA-ICP-MS锆石U-Pb年代学、成因及构造环境  

LA-ICP-MS Zircon U-Pb Geochronology,Petrogenesis and Tectonic Setting of Oytag-Gaizi Plagiogranites in the Northern Margin of West Kunlun

作　　者：朱泉龙 邱瑞照[3] 陈金勇[1,2] 祁翼 周肃 王生云[1,2] 高鹏[6] Zhu Quanlong;Qiu Ruizhao;Chen Jinyong;Qi Yi;Wang Shengyun;Zhou Su;Gao Peng(Beijing Research Institute of Uranium Geology,Beijing,100029,China;Jiangsu environmental science and Technology Co.,Ltd.Jiangsu 100029,China;Development and Research Center,China Geological Survey,Beijing,100037,China;Institute of Earth Sciences,China University of Geosciences(Beijing),Beijing 100083,China;Institute of Geology and Mineral Resources,Xinjiang Uygur Autonomous Region,Urumqi,Xinjiang,830000,China)

机构地区：[1]核工业北京地质研究院,北京100029 [2]江苏龙环环境科技有限公司,江苏常州213022 [3]中国地质调查局发展研究中心,北京100037 [4]紫金矿业集团股份有限公司矿产地质勘查院,福建厦门361000 [5]中国地质大学(北京)地球科学研究所,北京100083 [6]新疆维吾尔自治区地质矿产研究所,新疆乌鲁木齐830000

出　　处：《新疆地质》2022年第2期176-183,共8页Xinjiang Geology

基　　金：“十二五”国家科技支撑计划项目昆盖山海相火山岩铜多金属成矿作用与靶区评价(2015BAB05B02-2);中国国家预研究项目(3210408号)共同资助。

摘　　要：为进一步明确西昆仑北缘斜长花岗岩成因和构造环境,以奥依塔克-盖孜一带出露的斜长花岗岩为研究对象,进行岩石学、U-Pb年代学和地球化学方面研究。该区花岗岩侵入于下石炭统中基性火山-沉积岩和中元古代赛图拉群中,岩石组合为:中粗粒花岗闪长岩、细粒英云闪长岩、石英闪长岩、奥长花岗岩,岩石类型间有明显细粒冷凝边。通过对区域内斜长花岗岩进行锆石U-Pb定年,获得LA-ICP-MS锆石U-Pb年龄为(337.7±9)Ma,指示为早石炭世岩浆活动产物。奥依塔克地区斜长花岗岩为“I”型花岗岩,富集大离子亲石元素Rb,Th,U,Pb等,亏损Nb,Ta,Sr,Ti等元素,具岛弧岩浆基本特征。研究表明,该斜长花岗岩来源于年轻的底侵玄武质岩浆,经部分熔融形成,形成环境为岛弧构造环境。In order to further clarify the genesis and tectonic environment of granite in the northern margin of West Kunlun.This study focuses on the plagiogranite exposed in Oytag-Gaizi area,and by Petrology,U-Pb chronology and geochemistry,we suggest that the plagiogranite intruded in the lower Carboniferous middle-basic volcanic-sedimentary rocks and the Mesoproterozoic Setura Group in this area,with rock assemblages of medium-coarse-grained granodiorite,fine tonalite,quartz diorite,and fine grained minerals as chilled edges can be observed between them.The result of LA ICP-MS zircon U-Pb dating of plagiogranite shows that it formed at 337.7±9 Ma.This means that plagiogranite is the product of Early Carboniferous magmatic activity.The plagioclase granite exposed in the Oytag-Gaizi area is type I gran-ite,which has the characteristics of high silicon,rich aluminum and low alkali.The total amount of rare earth is low,and the overall has a strong negative Eu anomaly.The sample is rich in large ion lithophile elements Rb,Th,U,Pb,and de-pleted in Nb,Ta,Sr,Ti and other elements,which has the basic characteristics of island arc magma.The study shows that the plagioclase granite comes from young underplating basaltic magma and it is formed by partial melting in an island arc tectonic environment.

关 键 词：奥依塔克-盖孜 斜长花岗岩 岩石地球化学 岩石成因 构造环境 

分 类 号：P619.222[天文地球—矿床学] P597[天文地球—地质学]