黔西北香炉山铜矿床赋矿主岩矿物岩石学研究

摘要

黔西北威宁地区香炉山铜矿床位于二叠系峨眉山玄武岩组第3段(P3β3)顶部与宣威组(P3x)底部之间,属于玄武岩型铜矿床.针对其含矿地层宏观地质特征与赋矿主岩矿物岩石学组构,本文以野外地质为基础,系统开展岩矿鉴定、扫描电镜与电子探针分析等研究,结果表明,本矿床赋矿主岩为岩屑粉砂岩的矿石矿物为辉铜矿、斑铜矿、黝铜矿和孔雀石,脉石矿物为长石、石英、绿泥石和碳质物等;赋矿主岩为火山角砾岩的矿石矿物为自然铜、斑铜矿、黄铜矿、辉铜矿、黝铜矿和孔雀石,其脉石矿物为石英、绿泥石、白云石和粘土矿物等,按其主要矿物含量,原生矿石可分为自然铜+辉铜矿+赤铁矿矿石、自然铜+黄铜矿+黝铜矿矿石、黄铜矿+斑铜矿+赤铁矿矿石3种自然类型.根据矿物共生组合与相互穿插关系,本矿床成矿作用可分为热液期和表生期,其中,热液期矿石矿物的形成顺序为斑铜矿→黄铜矿—黝铜矿—自然铜→辉铜矿,表生期形成孔雀石、赤铜矿、赤铁矿、钛铁矿、褐铁矿等矿物.%The Xianglushan copper deposit in Weining of northwest Guizhou is located in the copper bed between the top of the third unit of Emeishan basalt Formation and the bottom of Xuanwei Formation,and belongs to basalt type copper deposit.In order to study the geological characteristics of copper-hosting strata and mineralogical and petrological characteristics of copper-hosting rocks,the authors carried out rock-mineral determination,scanning electron microscope and electron microprobe analysis systematically in combination with field geological survey.The results show that the ore minerals of lithic siltstone are mainly composed of chalcocite,etrahedrite,bornite and malachite,and gangue minerals are mainly feldspar,quartz,chlorite and carbonaceous materials;the ore minerals of volcanic breccia are mainly composed of pyrite,bornite,chalcopyrite,chalcocite,tetrahedrite and malachite,and gangue minerals are mainly quartz,chlorite,dolomite and clay minerals.According to main mineral content,primary ores can be divided into three natural types,i.e.,natural copper + chalcocite + hematite ore,natural copper + chalcopyrite + tetrahedrite ore and chalcopyrite + bornite + hematite ore.On the basis of mineral assemblages and intercalation relationship,mineralization can be divided into hydrothermal stage and supergene stage.The sequence of ore minerals at the hydrothermal stage is bornite→chalcopyrite-tetrahedrite-natural copper→chalcocite.At the supergene stage,malachite,hematite,hematite,ilmenite and limonite have been formed.