西藏冈底斯带南部雄村铜金矿成因探讨--来自锆石U-Pb年龄的证据

The genesis of the Xiongcun copper-gold deposit in southern Gangdise,Tibet:evidence from zircon U-Pb SHRIMP ages

对西藏冈底斯带南部雄村铜金矿床的容矿火山岩和外围岩石进行了岩石学、地球化学、锆石年代学研究。雄村容矿火山岩锆石(XC01-1,流纹质凝灰岩)U-Pb SHRIMP年龄的测定值为180.4±3.5Ma,表明这套火山岩是形成于早侏罗世而不是此前一致公认的晚白垩世。外围二长花岗岩(XTM04-1)U-Pb SHRIMP年龄的测定值为46.6±0.6Ma,表明其侵位于成矿时代的始新世。结合前人的研究成果,认为雄村铜金矿床与胶东焦家式金矿床具有很大的相似性,属于破碎带蚀变岩型铜金矿床。

Based on a systematic petrographic and geochemical study and a zircon U-Pb SHRIMP age analysis, the authors revealed that the age of ore-hosting volcanics （XC01-1 rhyolitic tuff） is 180.4 ± 3.5 Ma. This age suggests that the volcanic suite was formed in Early Jurassic instead of formerly widely-accepted Late Cretaceous. The age of peripheral monzonitic granite （XTM04-1） is 46.6 ±0.6 Ma, implying that this granite suite was formed in the oreforming stage of Eocene. According to these data, the authors tend to believe that the Xiongcun superlarge deposit belongs probably to the altered cataclastite type Cu-Au deposit, and is very similar to Jiaodong ＂Jiaojia-style＂ gold deposits.