湖南天明金矿床Cu-Zn合金矿物的发现及地质意义  

Discovery and significance of Cu-Zn intermetallic compounds in the Tianming gold deposit,Hunan Province

作　　者：吴金虹 章志明 陈澍民 潘思远 曾昊 肖涛 彭勃 WU Jinhong;ZHANG Zhiming;CHEN Shumin;PAN Siyuan;ZENG Hao;XIAO Tao;PENG Bo(Changsha Natural Resources Comprehensive Survey Centre,China Geological Survey,Changsha 410600,Hunan,China;School of Earth Sciences and Resources,China University of Geosciences(Beijing),Beijing 100083,China;Institute of Mineral Resources,Chinese Academy of Geological Sciences,Beijing 100037,China)

机构地区：[1]中国地质调查局长沙自然资源综合调查中心,湖南长沙410600 [2]中国地质大学(北京)地球科学与资源学院,北京100083 [3]中国地质科学院矿产资源研究所,北京100037

出　　处：《矿产勘查》2024年第12期2226-2233,共8页Mineral Exploration

基　　金：中国地质调查局项目“湖南云台山地区1∶5万矿产地质调查”(ZD20220308);“雪峰弧金锑矿资源勘查”(DD20208007);湖南省溆浦县大和矿业有限公司“湖南省溆浦县观音堂矿区锑矿勘查”(长自调合[矿]2023-128)联合资助。

摘　　要：湖南安化县天明金矿床是雪峰成矿带上新探明的一个中低温热液型金矿床。本文勘查发现该矿床的矿化类型为石英-黄铁矿脉型,金主要赋存在黄铁矿中。为研究天明金矿床物质组分特征,通过对石英黄铁矿矿脉中金属硫化物开展显微镜观察和电子探针分析,发现了天明金矿α+β-Cu-Zn合金化学分子式为Cu_(0.60)Zn_(0.37)Pb_(0.01)Fe_(0.01),Cu的质量分数为57.12%~58.73%,Zn的质量分数为36.60%~37.84%;黄铁矿化学分子式为Fe_(1.03)S2,Fe的质量分数为46.29%~46.65%,硫亏损(S/Fe<2);含砷黝铜矿化学分子式为Cu_(0.77)Sb_(0.18)Zn_(0.13)As_(0.12)Fe_(0.02)S,Cu的质量分数为38.592%~39.599%,Sb为17.620%~18.445%。结合天明金矿床成矿特征和区域成矿条件,笔者认为天明金矿床Cu-Zn合金的形成为岩浆快速上升,在局部缺氧的还原环境下,压力突然下降,较短的时间导致硫与金属元素间难以结合,而自然沉淀形成。天明金矿床α+β-Cu-Zn合金矿物在雪峰成矿带的首次发现,对在该成矿带寻找相同石英-黄铁矿脉型金矿床具有重要的指示意义。The Tianming gold deposit in Anhua County,Hunan Province is a newly discovered medium to low temperature hydrothermal gold deposit on the Xuefeng orogenic belt,whose the mineralization type is quartz pyrite vein type,with gold mainly occurring in pyrite.To study the material composition characteristics of the Tianming gold deposit,microscopic observation and electron probe analysis of metal sulfides in quartz pyrite veins were carried out.We found that the chemical molecular formula ofα+β-Cu-Zn alloy is Cu_(0.60)Zn_(0.37)Pb_(0.01)Fe_(0.01),with a mass fraction of 57.12%to 58.73%for Cu and 36.60%to 37.84%for Zn;The chemical formula of pyrite is Fe_(1.03)S_(2),with a mass fraction of Fe ranging from 46.29%to 46.65%,resulting in sulfur deficiency(S/Fe<2);The chemical formula of arsenic containing tetrahedrite is Cu_(0.77)Sb_(0.18)Zn_(0.13)As_(0.12)Fe_(0.02)S,with a mass fraction of 38.592%-39.599%for Cu and 17.620%-18.445%for Sb.Based on the ore-forming characteristics and regional ore-forming conditions of the Tianming gold deposit,we suggest that the rapid magma upwelling,the sudden drop in pressure,and the rapid separation of fluids in a topo-reducing environment,difficult to combine sulfur and metal elements in a relatively short period of time,thus deposit to form.The discovery of Cu Zn alloy minerals in the Tianming gold deposit in the Xuefeng mineralization zone is the first time,which has important indicative significance for searching for similar quartz pyrite vein type gold deposits in this mineralization zone.

关 键 词：雪峰造山带 天明金矿床 铜锌合金矿物 含砷黝铜矿 地质意义 

分 类 号：P618[天文地球—矿床学]