CAJ | 학술논문

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34.7～35.7 Ma,平均为35 Ma;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Sin-Nd等时线方法测定莫海拉亨矿床的成矿时代为31.8～33.9 Ma,平均为33 Ma,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1 000 km的狭长地带有望成为一条巨型Pb-Zn成矿带.
청해옥수지구적동막찰조화막해랍형연자광상시"삼강"북단동연자다금속성광대연자광상적전형대표,처우옥수역충추복구조대적전봉대위치.본문이용단광물섬자광화공생광물조합황철광여방연광Rb-Sr등시선방법이급공생광물조합섬자광여황철광Sm-Nd등시선방법측정동막찰조광상적성광시대위34.7～35.7 Ma,평균위35 Ma;이용단광물섬자광화공생광물조합섬자광여방연광Rb-Sr등시선방법이급단광물형석화공생광물조합방해석여형석Sin-Nd등시선방법측정막해랍형광상적성광시대위31.8～33.9 Ma,평균위33 Ma,표명2개광상적성광시대기본일치,위동기동원성광작용적산물.결합구역성광지질배경,건립료2개광상적구조공광모식.차외,본문획득적옥수지구전형연자광상적성광시대여"삼강"남단란평분지화"삼강"북단타타하분지연자광상적성광시대상근,증명청장고원동부화북부수역충추복공제적장체1 000 km적협장지대유망성위일조거형Pb-Zn성광대.
Dongmozhazhua and Mohailaheng Pb-Zn deposits in Yushu area of Qinghai Province are representative Pb-Zn deposits in the Cu-Pb-Zn polymetallic mineralization 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 Dongmozhazhua de posit have been determined by the Rb-Sr isochron method for sphalerite and one group of intergrowth mineral as semblage samples (pyrite and galena) and the Sm-Nd isochron method for one group of intergrowth mineral as semblage samples (sphalerite and pyrite); whereas, the ages of the Mohailaheng deposit have been determined by the Rb-Sr isochron method for sphalerite and one group of intergrowth mineral assemblage samples (spha lerite and galena) and the Sm-Nd isochron method 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 geological and geochemical data, it is concluded that the Dongmozhazhua and Mohailaheng deposits formed during the same geological event and the metals have the same source. Togeth er with regional mineralization geological setting, a possible 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 area and in Tuotuohe basin of the northern part of the Nujiang-Lancangjiang-Jinshajiang 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.