玉树地区东莫扎抓和莫海拉亨铅锌矿床Rb-Sr和Sm-Nd等时线年龄及其地质意义  

Rb-Sr and Sm-Nd isochron ages of Dongmozhazhua and Mohailaheng Pb-Zn ore deposits in Yushu area,southern Qinghai and their geological implications

作　　者：田世洪[1] 杨竹森[1] 侯增谦[2] 刘英超[1,2] 高延光[3] 王召林[2,4] 宋玉财[2] 薛万文[5] 鲁海峰[5] 王富春[5] 苏嫒娜[1,6] 李真真[1,7] 王银喜[8] 张玉宝[5] 朱田[5] 俞长捷[5] 于玉帅[1] 

机构地区：[1]中国地质科学院矿产资源研究所国土资源部成矿作用与资源评价重点实验室,北京100037 [2]中国地质科学院地质研究所,北京100037 [3]中国地质调查局,北京100037 [4]有色金属矿产地质调查中心,北京100012 [5]青海省地质调查院,青海西宁810012 [6]东华理工大学,江西抚州344000 [7]昆明理工大学,云南昆明650093 [8]南京大学现代分析中心,江苏南京210093

出　　处：《矿床地质》2009年第6期747-758,共12页Mineral Deposits

基　　金："十一五"国家科技支撑计划重大项目(2006BAB01A08);国家973项目(2009CB421007);国土资源大调查项目(1212010818096);中央级公益性科研院所基本科研业务费专项资金(K0802);中国博士后科学基金(20070420418);国家基础研究计划973项目(2002GB41260);南京大学内生金属矿床成矿机制研究国家重点实验室资金(13-7-5);东华理工大学核资源与环境教育部重点实验室项目(081206)的联合资助

摘　　要：青海玉树地区的东莫扎抓和莫海拉亨铅锌矿床是"三江"北段铜铅锌多金属成矿带铅锌矿床的典型代表,处于玉树逆冲推覆构造带的前锋带位置。本文利用单矿物闪锌矿和共生矿物组合黄铁矿与方铅矿Rb-Sr等时线方法以及共生矿物组合闪锌矿与黄铁矿Sm-Nd等时线方法测定东莫扎抓矿床的成矿时代为34.7～35.7Ma,平均为35Ma;利用单矿物闪锌矿和共生矿物组合闪锌矿与方铅矿Rb-Sr等时线方法以及单矿物萤石和共生矿物组合方解石与萤石Sm-Nd等时线方法测定莫海拉亨矿床的成矿时代为31.8～33.9Ma,平均为33Ma,表明2个矿床的成矿时代基本一致,为同期同源成矿作用的产物。结合区域成矿地质背景,建立了2个矿床的构造控矿模式。此外,本文获得的玉树地区典型铅锌矿床的成矿时代与"三江"南段兰坪盆地和"三江"北段沱沱河盆地铅锌矿床的成矿时代相近,证明青藏高原东部和北部受逆冲推覆控制的长达1000km的狭长地带有望成为一条巨型Pb-Zn成矿带。Dongmozhazhua and Mohailaheng Pb-Zn deposits in Yushu area of Qinghai Province a re representative Pb-Zn deposits in the Cu-Pb-Zn polymetallic mineralizat io n belt of the northern part of the Nujiang-Lancangjiang-Jinshajiang area, which are in the front belt of Yushu thrust nappe system. The ages of the Dongmozhazhu a deposit have been determined by the Rb-Sr isochron method for sphalerite and o ne group of intergrowth mineral assemblage samples （pyrite and galena） and the S m-Nd isochron method for one group of intergrowth mineral assemblage samples （sp halerite and pyrite）; whereas, the ages of the Mohailaheng deposit have been det ermined by the Rb-Sr isochron method for sphalerite and one group of intergrowth mineral assemblage samples （sphalerite and galena） and the Sm-Nd isochron metho d for fluorite and one group of intergrowth mineral assemblage samples （calcite and fluorite）. The ages of Dongmozhazhua and Mohailaheng deposits are 34.7-35 .7 Ma with an average of 35 Ma and 31.8-33.9 Ma with an average of 33 Ma, respectively, implying they have the same mineralization epoch. Combined with g eological and geochemical data, it is concluded that the Dongmozhazhua and Mohai laheng deposits formed during the same geological event and the metals have the same source. Together with regional mineralization geological setting, a possibl e tectonic model for metallogeny of Dongmozhazhua and Mohailaheng Pb-Zn deposits has been established. These two ages are close to the ages of the Pb-Zn deposit in Lanping basin of the southern part of the Nujiang-Lancangjiang_Jinshajiang a rea and in Tuotuohe basin of the northern part of the Nujiang-Lancangjiang-Jinsh ajiang area, indicating that it is possible that the narrow 1000 km-length belt controlled by thrust nappe system in the eastern and northern margins of Tibetan plateau would be a giant Pb-Zn mineralization belt. 

关 键 词：地球化学 RB-SR等时线 Sm-Nd等时线 共生矿物组合 成矿时代 逆冲推覆构造 构造模式 青海玉树东莫扎抓和莫海拉亨铅锌矿床 

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