义敦岛弧带夏塞银铅锌矿床地质、物化探特征及综合找矿模型  

Geological, geophysical and geochemical characteristics and comprehensive prospecting model of the Xiasai Ag-Pb-Zn deposit in the Yindun Island Arc

作　　者：李艳军[1] 魏俊浩[1] 李欢[1] 陈冲[2] 陕亮[3] 侯本俊 

机构地区：[1]中国地质大学(武汉)资源学院,湖北武汉430074 [2]中国地质调查局武汉地质调查中心,湖北武汉430205 [3]中国地质调查局发展研究中心,北京100037 [4]四川夏塞银业有限责任公司,四川甘孜626000

出　　处：《中国地质》2014年第5期1636-1649,共14页Geology in China

基　　金：国家自然科学基金(41202054);中国地质大学(武汉)中央高校基本科研业务费专项基金(CUG110832;CUG120702)联合资助

摘　　要：夏塞银铅锌矿床位于义敦岛弧带中段,为典型的与早白垩世A型花岗岩有关的热液脉型矿床。矿体呈脉状、透镜状产于NNW向断裂构造中,具有向北侧伏、尖灭再现特点。从花岗岩体接触带往北发育Sn-Cu→Cu-Zn→Ag-Pb矿化分带。硅化、绢云母化、绿泥石化等蚀变与成矿关系密切。成矿过程划分为锡石、毒砂、闪锌矿-黄铜矿、含银矿物-方铅矿、黄铁矿-碳酸盐5个成矿阶段。高精度磁法测量ΔT正异常能有效识别矿化带或控矿断裂带。土壤地球化学测量Ag、Pb、Zn、Cu元素变化曲线峰值能指示矿化体的存在。据此建立了夏塞银铅锌矿床地质、磁法和土壤地球化学测量综合找矿模型,经验证找矿效果良好。有望为夏塞—连龙银锡多金属矿集区热液脉型矿床找矿勘查和评价工作提供重要参考。Located in central of the Yindun Island Arc, the Xiasai Ag- Pb- Zn deposit is a typical hydrothermal vein deposit associated with early Cretaceous A-type granite. Orebodies commonly occur as lodes, lenses and strings of beads controlled by the NNW-trending faults. They pinch northward and are characterized by pinch out-reproduction and branching-complexing. From south to north, metallogenic element zoning is in order of Sn-Cu→Cu-Zn→Ag-Pb, constituting a complete metallogenic element zoning and ore mineral zoning related to magmatism. Ore-related hydrothermal alteration is well developed and dominated by silicification, sericitization and chloritization with a banded alteration zonation. The ore-forming process can be divided into five stages, i.e., cassiterite stage, arsenopyrite stage, sphalerite-chalcopyrite stage, silver-rich mineral-galena stage and pyrite- carbonate stage. The AT positive anomalies of high-precision magnetic survey with extension of 20 m can be used as a geophysical prospecting indicator because they can accurately identify mineralized veins or ore-bearing faults. In addition, anomalies of soil geochemical survey with extension of 20 m consist of Ag, Pb, Zn and Cu elements, and their variation trend can also accurately identify mineralized veins or ore-bearing faults. Combined with geological, high-precision magnetic and soil geochemical characteristics of the Xiasai Ag- Pb- Zn deposit, the authors propose a comprehensive prospecting model in the search for new orebodies. The subsequent geological verification shows a good prospecting effect. It is thus held that the comprehensive prospecting model has important reference significance for the prospecting work of the Xiasai Ag-Pb-Zn deposit and hydrothermal veined Ag polymetallic deposits in the Xiasai-Lianlong Ag-Sn ore district within the central Yidun Island Arc of Southwest China.

关 键 词：热液脉型矿床 综合找矿模型 夏塞银铅锌矿床 义敦岛弧带 

分 类 号：P618.4[天文地球—矿床学] P618.52[天文地球—地质学]