白干湖钨锡矿田位于东昆仑祁漫塔格西段新疆维吾尔自治区若羌县境内。笔者通过对柯可卡尔德、白干湖、巴什尔希和阿瓦尔4处矿床实地剖析,认为这些矿床已构成一个集矽卡岩型、云英岩化花岗岩微细网脉浸染型和石英脉型交代、充填叠加复合的具超大型远景规模的钨锡矿田。矿田内矿化类型显示出一定的分布规律或分带性:即产于花岗岩边部外接触带的矽卡岩型白钨矿矿体,呈透镜状或似层状分布在金水口群浅变质岩系大理岩内;产于花岗岩小突起内侧及其顶部外接触带伸枝脉岩的云英岩化花岗岩微细网脉浸染型钨锡矿体,前者呈厚板状透镜体面型分布,后者则呈脉状线型分布于围岩地层中;产于隐伏花岗岩突起上部外接触带的石英脉充填交代型锡石黑钨矿矿体,其因受区域NE向白干湖深大断裂构造限制,多呈低缓角度的平行脉状充填于金水口群浅变质岩系的绢云石英片岩中。根据矿石矿物组合等特征,矿田内的矿化蚀变可划分为3种:即矽卡岩化、云英岩化(包括钠长石化、电气石化等)和硅化。研究表明,矿田内矽卡岩型白钨矿化、云英岩化花岗岩微细网脉浸染型钨锡矿化和石英脉充填交代型锡石黑钨矿化构成一个与加里东期中细粒(似斑状)二长花岗岩侵入活动有成因联系的矿田成矿系列,属于岩浆期后高温-气化热液交代和中低温热液充填交代形成的产物。
The Baiganhu tungsten-tin orefield is located in Ruoqiang County of Xinjiang,lying in the west of the Qimantag Mountain along the East Kunlun Mountains.The authors hold that several ore deposits such as Kekekaerde Baiganhu,Bashierxi and Aerwa constitute the superlarge tungsten-tin orefield characterized by the combination of the skarn type,the greisenized granite fine veinlet dissemination type and the quartz vein type.Mineralization types show certain extent of distribution and zoning inside the orefield:the scheelite skarn deposit occurs in the outer contact zone of granite,the ore bodies stratoid and lenticular in form distributed in the marble of the epimetamorphic rock series of Jinshuikou Group;the tungsten-tin ore bodies of greisenized granite fine veinlet dissemination type lie inside the small bumps of the granite and extended veins of the outer contact zone,the former is in areal distribution in the form of thick plate lens,and the latter is in linear distribution in surrounding rocks;cassiterite-wolframite ore bodies of quartz vein type are seen in the outer contact zone of the upper bumps of concealed granite.Confined by regional NE-trending Baiganhu deep fault,the ore bodies in the form of parallel veins are filled in epimetamorphic sericite-quartz schist of Jinshuikou Group at a low angle.According to the characteristics of the ore mineral combination,the mineralization alteration in the orefield can be divided into three main types:skarn,greisenization(including albitization,tourmalinization) and silicification.Studies show that three different ore bodies which have genetic relationship with the adamellite invasive activity in Caledonian constitute the metallogenic series of the orefield and belong to the metasomatism of the post-magmatic high temperature-tungsten and tin type.