吉林大黑山超大型钼矿辉钼矿铼-锇同位素定年及其地质意义

Re-Os Isotopic Dating of Molybdenite from the Daheishan Molybdenum Deposit of Jilin Province and Its Geological Significance

摘要: 吉林大黑山钼矿位于吉黑成矿省，是20世纪50年代发现的一超大型斑岩型钼矿床。文章首次对采自矿床不同类型矿石中的辉钼矿进行了铼-锇同位素定年，获得等时线年龄为（168.2±3.2） Ma，其加权平均方差（MSWD）为0.56，表明大黑山钼矿主要形成于燕山早期。结合该区域其他钼矿的成矿年龄，燕山早期可能为吉林中部钼矿的成矿集中期。根据辉钼矿中的铼含量及矿床硫同位素特征表明，矿床的成矿物质来源为壳幔混源。矿床的形成可能与谷太平洋板块的俯冲有关，构造作用与岩浆作用的耦合是成矿的关键因素。

Abstract: The Daheishan molybdenum deposit is a large-scale porphyry molybdenum deposit discovered in 1950s in Jilin Province. This study provides a high-precision Re-Os isotopic dating for ten molybdenite separated from the different ore types with an isochron age of (168.2±3.2) Ma (MSWD=0.56). The results indicate that the deposit was formed in the early of Yanshanian period. The content of element Re from the molybdenite and S isotope composition from the pyrites show that the oreforming materials may come from mixed crustal and mantle sources.