西藏夏垅铅锌银矿床绢云母^40Ar^39Ar年龄及其地质意义  

(40)~Ar/(39)~Ar dating of sericite from Xialong Pb-Zn-Ag deposit and its geological significance

作　　者：赵晓燕[1,2] 杨竹森[2] 刘英超[3] 纪现华[1] 费凡[1] 徐玉涛[1] 

机构地区：[1]中国地质大学地球科学与资源学院,北京100083 [2]中国地质科学院矿产资源研究所,北京100037 [3]中国地质科学院地质研究所,北京100037

出　　处：《矿床地质》2013年第5期963-971,共9页Mineral Deposits

基　　金：国家重点基础发展计划(973计划)“青藏高原南部大陆聚合与成矿作用”(编号:2011CB4031006)项目;中国地质调查局地质调查项目(编号:1212011121253)的联合资助

摘　　要：西藏冈底斯成矿带位于班公湖-怒江缝合带与雅鲁藏布江缝合带之间,从北向南依次可划分为3个成矿亚带:勒青拉-洞中松多铅锌银多金属成矿亚带,驱龙-甲马-邦铺斑岩铜钼成矿亚带,克鲁-冲木达斑岩-矽卡岩铜钼金成矿亚带。驱龙-甲马-邦铺成矿亚带内矿床的类型以斑岩型为主,部分伴生有矽卡岩型及热液脉型矿床。夏垅矿床位于驱龙-甲马-邦铺斑岩铜钼成矿亚带的西段,产于黑云母二长花岗岩基中,属于隐爆角砾岩型铅锌银多金属矿床。对夏垅矿床内与石英、方铅矿、闪锌矿密切共生的绢云母进行了40Ar-39Ar定年,确定其坪年龄及反等时线年龄分别为(23.56±0.22)Ma和(23.9±1.6)Ma。该矿床作为隐爆角砾岩型铅锌银多金属矿床的发现以及冈底斯火山岩自西向东逐渐变年轻的时空迁移规律说明在冈底斯成矿带的西侧存在着岩浆活动。夏垅矿床成矿年龄的精确测定把驱龙-甲马-邦铺斑岩铜钼成矿亚带向西延伸了120 km,增大了该成矿亚带的找矿潜力,为在该成矿亚带内寻找此类铅锌银多金属矿床提供了理论及实际依据。Lying between Bangonghu-Nujiang suture zone and Yarlung Zangbo suture zone,the Gangdise metallogenic belt of Tibet can be divided into three metallogenic subbelts,which are from north to south LeqinglaDongzhongsongduo Pb-Zn-Ag polymetal metallogenic subbelt,Qulong-Jiama-Bangpu porphyry Cu-Mo metallogenic subbelt and Kelu-Chongmuda porphyry-skarn Cu-Mo-Au metallogenic subbelt.The Qulong-Jiama-Bangpu metallogenic subbeltis mainly characterized by porphyry Cu-Mo mineralization,with some depositswithin it also having Pb-Zn mineralization.The Xialong deposit is located in the west of the Qulong-Jiama-Bangpu metallogenic subbelt and occurs in the biotite monzonitic granite,belonging to the cryptoexplosive brecciated Pb-Zn-Ag deposit.40Ar/39Ar dating of sericite that is highly related to mineralization yielded the plateau age and isochronage of（23.56±0.22）Ma and（23.9±1.6）Ma respectively.The successful discovery of the Xialong deposit and the migration characteristics of Gangdise volcanic rocks from west to east indicate that there existed magmatism in the west of Gangdise metallogenic belt.The precise determination of the age of the Xialong deposit results in the westward extension of the Qulong-Jiama-Bangpu porphyry Cu-Mo metallogenic subbelt for 120 km, which increases the potential of ore prospecting in the Qulong-Jiama-Bangpu metallogenic subbelt and provides the theoretic and actual foundation for exploring Pb-Zn-Ag mineral commodities in this subbelt.

关 键 词：地球化学 40Ar/39Ar定年 绢云母 夏垅铅锌银矿床 驱龙-甲马-邦铺斑岩铜钼成矿亚带 西藏 

分 类 号：P618.42[天文地球—矿床学] P618.43[天文地球—地质学]