广西大瑶山地区加里东期石英脉型金矿:上木水金矿白云母Ar-Ar年龄约束

Caledonian Quartz Vein Type Gold Mineralization in the Dayaoshan Area,Guangxi: Constraint from the Muscovite ^(39)Ar/^(40)Ar Dating in the Shangmushui Gold Deposit

石英脉型金矿是广西大瑶山地区主要的金矿床类型之一,但一直没有高精度的年龄数据约束其成矿时代。论文首次对大瑶山南部广西苍梧县上木水石英脉型金矿中的热液白云母进行^(39)Ar/^(40)Ar年龄法测年,获得坪年龄为(432.6±3.2)Ma,相应的等时线年龄为(428.2±7.2)Ma,反等时线年龄为(425.3±6.6)Ma,表明其成矿时代为加里东期。这一数据进一步证明大瑶山南部的古龙-夏郢环形成矿区主要以加里东期矿化为主,除了与加里东期岩浆岩有关的斑岩-矽卡岩型钨多金属矿化外,还存在石英脉型金矿。同时,位于大瑶山中部沿区域性大黎断裂分布的六岑-桃花-古袍金矿田的石英脉型金矿时代仍然不明确,还需要进一步的高精度测年数据来约束。

Quartz vein type gold deposit is one of the most important gold deposit types in the Dayaoshan area,Guangxi Province.However,there has been no high precision age data to constrain its mineralization epoch.This paper firstly used muscovite 39Ar/40Ar dating to constrain the age of Shangmushui quartz vein type gold deposit in the southern Dayaoshan area from Cangwu County,Guangxi Province.The study yielded a plateau age of 432.6±3.2 Ma,an isochron age of 428.2±7.2 Ma,and an inverseisochron age of 425.3±6.6 Ma,indicating its mineralization epoch is Caledonian.These new data further demonstrate that the Caledonian is the main mineralogenetic epoch in the Gulong-Xiaying ore-forming area from the southern Dayaoshan area.Except for the Caledonian granitoids related porphyry-skarn tungsten polymetallic mineralization,there are quartz vein type gold deposits.Meanwhile,the timing of Liucen-Taohua-Gupao gold ore field along the regional Dali fault is not clear and the oreforming age will need to be constrained by high precision clating data in the future.