豆乍山地区产铀与非产铀岩体黑云母成分及赋存副矿物特征

豆乍山岩体和香草坪岩体成岩时代相近,空间关系密切,为苗儿山中段豆乍山地区产铀与非产铀岩体。文章选择豆乍山和香草坪新鲜花岗岩中黑云母为研究对象,结合诸广、贵东地区产铀与非产铀岩体中黑云母的电子探针数据开展综合分析,并在此基础上进行了黑云母中包裹副矿物种类的对比研究。结果表明:产铀岩体黑云母基本以铁叶云母为主,非产铀岩体黑云母为铁质黑云母,且前者具有相对富铝、铁、锰,贫镁、钛特征;产铀豆乍山岩体黑云母中副矿物为锆石-磷钇矿-独居石-钛铁矿-金红石-方钍石-晶质铀矿,非产铀香草坪岩体黑云母中副矿物为锆石-磷灰石-褐帘石-独居石,缺少钍石和晶质铀矿。不同亚种黑云母具有不同的成岩成矿环境,与各矿化类型往往具有直接对应关系,铁叶云母的出现有可能可以作为产铀与非产铀岩体(铀成矿潜力)的间接判别标志,对于后期找矿具有较大指导意义。

The Geochemical Characteristics and Accessory Minerals of Biotite From U Deposit Bearing and U Deposit Barren Granite in Douzhashan Area

Located in the middle part of Miaoershan,Douzhashan pluton and Xiangcaoping pluton are similar in diagenetic times and near in spatial,but they are respectively the represent of U-deposit bearing and barren pluton.The fresh granites of Douzhashan and Xiangcaoping pluton were selected for the study of biotites.Based on the comprehensive analysis of electron microprobe data of biotite and the types of the accessory mineral the in Zhuguang,Guidong uranium orefield,It was found that the biotite in the U-deposit bearing granite was mainly composed of siderophyllite,while the biotites of the u-deposit barren granite was Fe-biotites in the diagram of(Fe^2++Mn)-(ⅥAl+Fe^3++Ti)-Mg.The former was relatively rich in aluminum,iron,manganese,low in magnesium,titanium.The SEM back scattering spectrum of Douzhashan granite and Xiangchaoping granite showed that the accessory mineral was obvious different.The former is a combination of zircon,xenotime,monazite,ilmenite,rutile,thorite,uraninite,and the latter is zircon,apatite,allanite,monazite,which is characterized by the lack of thorite and uraninite.In addition,different subspecies are different in diagenetic and metallogenic environment and there is a direct correspondence to the different types of mineralization.Therefore,the occurrence of siderophyllite can be used as an indirect discriminant mark for the uranium metallogenic potential of the U-deposit bearing and U-deposit barren granites.