滇东南白牛厂银多金属矿床铟分布规律及富集机制  

Indium distribution and enrichment mechanism of the Bainiuchang silver polymetallic deposit in southeastern Yunnan

作　　者：刘建平[1,2] 郑旭[1,2] 陈卫康 张洪培 丁涛 郑国龙[3] 刀俊山 LIU Jianping;ZHENG Xu;CHEN Weikang;ZHANG Hongpei;DING Tao;ZHENG Guolong;DAO Junshan(Key Laboratory of Metallogenic Prediction of Nonferrous Metals and Geological Environment Monitoring,Ministry of Education,Central South University,Changsha 410083,China;School of Geosciences and Info-Physics Engineering,Central South University,Changsha 410083,China;No.306 Geological Team,Yunnan Nonferrous Geological Bureau,Kunming 650000,China)

机构地区：[1]有色金属成矿预测与地质环境监测教育部重点实验室(中南大学),湖南长沙410083 [2]中南大学地球科学与信息物理学院,湖南长沙410083 [3]云南省有色地质局306队,云南昆明650000

出　　处：《中南大学学报（自然科学版）》2021年第9期3015-3033,共19页Journal of Central South University:Science and Technology

基　　金：国家重点研发计划项目(2018YFC0603901);国家自然科学基金资助项目(41872091)。

摘　　要：为揭示白牛厂银多金属矿床的铟分布规律及富集机制,在矿床勘探工程观测及样品采集基础上,采用光学显微镜、等离子体光谱仪、电子探针等技术手段,开展矿体组合化学样、矿石捡块样的化学成分分析、矿物组成及组合显微鉴定、矿物化学电子探针分析等。研究结果表明:白牛厂矿床F3断层中的V1矿体中近岩体端和V27及V28矿体具有明显铟富集特征,组合样铟质量分数最高达152μg/g,捡块样最高含铟790μg/g,具有重要的工业价值;闪锌矿、黝锡矿及黄铜矿是主要的富铟矿物,尤以闪锌矿最重要;闪锌矿Ⅰa和Ⅰb的铟质量分数分别为0.08%~0.44%和0.02%~0.14%,闪锌矿Ⅰc和闪锌矿Ⅱ中铟质量分数低于电子探针检测限,与闪锌矿Ⅰa共生的黄铜矿中铟质量分数较高,最高达0.11%;与闪锌矿Ⅰa共生的黝锡矿铟质量分数为0.03%~0.23%。综合矿体构造、矿石组构及矿物组成特征,认为白牛厂银多金属矿床为岩浆热液成矿作用的产物,经历了2个成矿期包含6个成矿阶段的成矿过程,其中铟主要富集于热液成矿期的铜锡锌硫化物阶段。结合矿床成矿地质条件及成矿作用过程,北西向平行的缓倾断层带是富铟矿体的容矿断裂,可能与该区挤压走滑活动有关,铟富集定位受控于此背景下的岩浆热液系统与断裂的耦合作用。In order to reveal the indium distribution and enrichment mechanism of the Bainiuchang deposit,ore chemical analysis of assemblage samples and picked samples of orebodies,and mineral identification and mineral chemical analysis were carried out using multi-technology,e.g.,optical microscopes,plasma spectrometer,electron probes microscope analyzer,on the base of the field observation of the exploration engineering.The results show that V1 orebody near intrusion in the F3 fault and the V27 and V28 orebodies have obvious indium enrichment,the highest indium mass fraction of the assemblage samples is up to 152μg/g,and the highest indium mass fraction of the picked samples is up to 790μg/g.Combined with mineral microscopic observation and mineral chemical analysis,sphalerite,stannite and chalcopyrite are the main indium-bearing minerals,especially sphalerite.The indium mass fraction of sphalerite Ia and Ib are 0.08%−0.44%and 0.02%−0.14%,respectively.The indium mass fraction of sphalerite Ic and sphalerite II are below the detection limit of the electron probe.Chalcopyrite intergrowth with sphalerite Ia has high indium mass fraction up to 0.11%.The indium mass fraction of stannite with sphalerite Ia contains 0.03%−0.23%indium.The Bainiuchang silver polymetallic deposit is the product of magmatic hydrothermal mineralization based on the feature of orebody structure,ore structure and texture and mineral assemblage.The deposit experiences two mineralization periods,including six mineralization stages,in which indium is mainly concentrated in the copper-tin-zinc sulfide stage of the hydrothermal period.Combined ore-forming geological conditions and the process of mineralization,the ore-hosting structure of the indium-rich orebodis is the NW-trending low-angle faults which is controlled by regional compressional strike-slip setting in this area.The indium enrichment and location is coupling controlled by magmatic fluid and the faults.

关 键 词：铟富集 矿物化学 成因 白牛厂银多金属矿床 滇东南 

分 类 号：P618.82[天文地球—矿床学]