厄立特里亚比萨(Bisha)VMS型多金属矿床的研究进展及认识  

Geological Characteristics,Tectonic Environment and the Type of Bisha Volcanic-Associated Massive Sulfide Polymetallic Deposit,Western Eritrea

作　　者：向鹏[1] 王建雄[1] 姚华舟[1] 李闫华[1] 李福林[1] 

机构地区：[1]中国地质调查局武汉地质调查中心,武汉430205

出　　处：《地质科技情报》2013年第5期118-125,共8页Geological Science and Technology Information

基　　金：中国地质调查局项目"全球巨型成矿带区域构造与成矿地质背景对比研究"(1212011220911)

摘　　要：比萨(Bisha)VMS型多金属矿床位于非洲东北部的厄立特里亚西部,是近年来新发现的大型VMS型多金属矿床。该矿床主要赋存于Nakfa群的一套双峰式火山岩系中,矿体形态为一个经历了褶皱的厚层状矿体。原生VMS矿体形成以后,受近地表风化和氧化作用,形成4个矿化分带,从表往下依次为:①氧化带,主要为Au、Ag矿化;②淋滤带,主要为Au、Ag、Pb矿化;③次生带,主要为Cu矿化;④原生块状硫化物带,主要为Zn、Cu矿化。通过对矿区及区域地质资料的综合总结,认为比萨矿床形成于岛弧裂谷或弧后裂谷环境。通过对矿区已有资料的总结和对比研究,确定矿床类型属于黑矿(Kuroko)型VMS矿床。The Bisha polymetallic deposit is a recently discovered large scale vcilcanic-associated massive sulfide （VMS） deposit in the west of Eritrea. The Bisha deposit is mainly hosted within a bimodal igneous suite, and is a thick bedded massive sulfide ore body that has been folded into an anticline. After the primary massive sulfide ore body formed, it has been affected by significant near surface oxidation and weathering processes which lead to the development of four distinct ore types or zones. From the surface to the deep, these zones are （1） Oxide zone with high gold and silver contents; （2） Leaching zone enriched in gold, silver, and lead; （3） Supergene sulfide zone with significant copper enrichment; （4） Primary mas- sive suliide zone with zinc, cupper mineralization. Combined with field and regional geological research, it is considered that the Bisha mineral deposit formed in the island-arc rift or back arc rift tectonic environ- ment. Through the comparative study on Bisha deposit and kurko deposit in Japan, it is determined that the Bisha deposit is the Kuroko type VMS deposit.

关 键 词：比萨（Bisha）VMS型矿床 地质特征 形成环境 矿床类型 找矿标志 厄立特里亚 

分 类 号：P618.2[天文地球—矿床学]