江西省武功山地区浒坑钨矿床辉钼矿Re-Os年龄及其地质意义

Re-Os dating of molybdenite from the Hukeng tungsten deposit in the Wugongshan area,Jiangxi Province,and its geological implications

浒坑钨矿床是位于江西省中部武功山成矿带的大型石英脉型黑钨矿床。为了确定该矿床的成矿时代,笔者选取了浒坑含钨石英脉中与黑钨矿共生的辉钼矿进行了高精度Re-Os同位素定年,并获得5个辉钼矿样品的Re-Os等时线年龄和模式加权平均年龄分别为150.2±2.2Ma和149.82±0.92Ma。测年数据表明浒坑钨矿床的成矿时代为150Ma左右,是华南地区中生代大规模成岩成矿作用高峰期的产物。辉钼矿含铼较低,表明成矿物质可能为地壳来源,与形成浒坑花岗岩体的燕山期重熔S型花岗岩岩浆活动有关。该矿床形成于燕山期岩石圈伸展减薄环境。

Hukeng tungsten deposit is one large scale quartz vein type wolframite deposit in the Wugongshan metallogenic belt in central Jiangxi Province. For the purpose of studying the chronology of the deposit, five molybdenite samples from the paragenetic wolframite in the W-bearing quartz veins were selected to do the Re-Os dating, yielding an isochrone age of 150.2±2.2Ma and weighted average model age of 149.82±0.92Ma. These results indicate the Hukeng tungsten deposit formed in about 150Ma and was the product of the peak period of Mesozoic large scale petrogenesis and metallogenesis in South China. The molybdenites from the Hukeng tungsten deposit have a very low content of Re, showing a crustal source for ore-forming materials. The deposit formed in the Yanshanian lithospheric extensional and thinning environment.