内蒙古乌拉特中旗图古日格金矿辉钼矿Re-Os同位素年龄及其意义

Molybdenite Re-Os dating of the Tugurige gold deposit,Urad Middle Banner,Inner Mongolia,and its geological significance

图古日格是内蒙古宝音图地块内的一例具有中型规模的金矿床.含金石英脉呈NW向穿插于各类晚古生代岩体与下元古界宝音图群地层中,矿体走向、倾向延伸相对稳定.金属矿物主要为黄铁矿、黄铜矿、方铅矿等,脉石矿物为石英、方解石等.发育硅化、绢云母化、绿泥石化、绿帘石化等围岩蚀变.与金共生的辉钼矿Re-Os等时线年龄为（305.6±4.5）Ma、模式年龄为（313.5±4.8）Ma,限定图古日格金矿是晚石炭世构造-岩浆活动的产物.辉钼矿Re含量介于42.42×10^-6 -307.7×10^-6,显示成矿物质可能为壳幔混合来源.

Tugurige is a middle-sized gold deposit in Buyant Block, Inner Mongolia. The NW-striking gold-bearing quartz veinspenetrate the Late Paleozoic rock mass and Lower Proterozoic Buyant Group. The orebody stably extends along the strike and thedip. The metallic minerals mainly include pyrite, chalcopyrite and galena, whereas the gangue minerals are predominately quartzand calcite. The alteration in the wall rocks includes silicification, sericitization and epidotization. The Re-Os dating of molybdenitesamples from gold ore yielded a Re-Os isochron age of （305.6±4.5） Ma with an average of （313.5±4.8） Ma. This implies that the Auand Mo mineralization occurred in Late Carboniferous. The Re content of molybdenites in the Tugurige gold deposit is 42.42×10^-6 -307.7×10^-6, suggesting that the ore-forming material was derived mainly from a mixed source of crust and mantle.