康滇铜成矿带大红山IOCG矿床石英脉中黄铜矿Re-Os定年与意义

Re-Os Isotopic Dating of Chalcopyrite in Quartz Vein from Dahongshan IOCG Deposit in Kangdian Copper Metallogenic Belt and Its Significance

扬子西南缘康滇铜成矿带是我国重要的铁铜金矿产资源产区,分布许多小-大型铁氧化物-铜-金(IOCG)矿床,而本次研究的大红山矿床属康滇铜成矿带内最大的IOCG矿床之一。由石英脉中黄铜矿测年结果可以看出,Re-Os等时线年龄为1115±28 Ma,加权平均年龄为1113±14 Ma。因此,石英脉中黄铜矿矿化年龄为1115 Ma,结合扬子西南缘成岩成矿关系、背景研究,表明该黄铜矿为Grenvillian造山运动期碰撞后板内伸展环境产物。Re-Os同位素体系中高187Re/187Os比值、低含量的普通Os和高射性成因187Os的组成,指示成矿物质可能主要为壳源。

Kangdian copper metallogenic belt in the western margin of the Yangtze platform is an important iron oxide-copper-gold mineral resources production area in China, and there are many small or large iron oxide-copper-gold （IOCG） deposits there. Dahongshan deposit we studied is one of the biggest IOCG deposits in Kangdian region. Dating results for chalcopyrite in quartz vein demonstrate that the Re-Osisochron age of 1115±28 Ma with the weighted average age of 1113±14 Ma. Therefore, the mineralization age of chalcopyrite in quartz vein is 1115 Ma. Combined with metallogenic relationship and background research, it is suggested that the chalcopyrite is the production in post-collisional intraplate extensional environment of Grenvillian orogenic movement period. Re - Os isotope system with high 187Re/187Os ratio, low content of common Os and high radioactive lS7Os indicate that the mineralizing materials are mainly from the crust.