尼日利亚赞法拉州安卡金矿地质特征及控矿因素分析

安卡金矿床所在的马如—安卡成矿带是尼日利亚西北部重要的金成矿带。为对该地区的找矿工作提供指导，通过填图、钻探、样品鉴定、化验分析等探矿工作，结合构造、地层、变质作用综合研究，厘清安卡金矿控矿因素。区域内主要构造为一组北北东向的逆冲推覆构造，和派生的一系列北西西向和北北西向共轭的次级断裂。断裂构造为成矿提供有利的容矿空间，成矿物质在破碎带就位。金主要以游离金发育于石英脉和蚀变岩带。含矿岩层为前寒武—寒武系的区域变质岩系，其岩性组合为千枚岩—片岩—片麻岩。矿化严格受构造控制，矿体的贫富、厚度与石英脉、围岩蚀变和断层破碎带厚度变化关系密切。矿床成因类型为大陆地壳流体成因的造山型金矿。

Geological Characteristics and Ore Controlling Factors of Anka Gold Deposit in Zamfara,Nigeria

Maru Anka greenstone belt where Anka Gold Deposit sited is an important gold metallogenic belt in northwestern Nigeria.In order to provide guidance for the prospecting work in this area,the ore controlling factors of Anka Gold Mine are clarified through mapping,drilling,sample identification,laboratory analysis,combined with comprehensive research on structure,stratum and metamorphism.The main structures in the area are a set of NNE thrust nappe structure and a series of NW and NNW conjugate secondary faults,the ore is constrained in Precambrian Cambrian regional metamorphic rock series.Metallogenic materials emplaced in the fracture zone,gold occurs as free gold in quartz veins and altered part of phyllite schist gneiss.Faults provide favorable space for ore forming,grade distribution and thickness of ore show strong relationships with the thickness of quartz vein,surrounding alteration and fracture zone.The genetic type of Anka gold deposit is classified as orogenic gold deposits of continental crust fluid origin.