湖南通道地区金矿床中黄铁矿成分标型特征及对矿床成因的启示  

Composition Typomorphic Characteristics of Pyrite and Its Genetic Implication for Gold Deposits in Tongdao County,Hunan Province

作　　者：高华 谢玉华 杨亮 张哲 柯新星 刘晓敏 罗建镖 刘琦[2,3] 刘继顺 王智琳[2,3] 孔华[2,3] GAO Hua;XIE Yuhua;YANG Liang;ZHANG Zhe;KE Xinxing;LIU Xiaomin;LUO Jianbiao;LIU Qi;LIU Jishun;WANG Zhilin;KONG Hua(301 Brigade,Hunan Nuclear Industry Geological Bureau,Changsha 410114,Hunan,China;Key Laboratory of Metallogenic Prediction of Nonferrous Metals,Ministry of Education,Central South University,Changsha 410083,Hunan,China;School of Geoscience and Info-Physics,Central South University,Changsha 410083,Hunan,China)

机构地区：[1]湖南省核工业地质局三〇一大队,湖南长沙410114 [2]中南大学有色金属成矿预测教育部重点实验室,湖南长沙410083 [3]中南大学地球科学与信息物理学院,湖南长沙410083

出　　处：《黄金科学技术》2020年第5期712-726,共15页Gold Science and Technology

基　　金：湖南省核工业地质局科研项目“雪峰弧形带南西段金、锑矿成矿条件分析及找矿前景研究”(编号:KY2018-301-01)资助。

摘　　要：通道地区位于雪峰弧形带西南段,区内金矿化较普遍,产出有茶溪、黄垢和金坑等中小型金矿床,但该区研究程度很低。为探讨矿床成因,对金矿床中不同产状的黄铁矿进行了成因矿物学研究。岩矿鉴定结果显示:3个金矿床黄铁矿晶形主要为立方体、五角十二面体和他形—半自形粒状;MLA面扫描结果显示,黄垢矿区金主要以裂隙金或包体金赋存在黄铁矿中。EPMA常量元素分析结果显示:黄铁矿总体上富铁亏硫,含少量砷。3个矿区黄铁矿的δFe、δS值分布集中,与变质热液型金矿床的特征一致。LA-ICPMS微量元素分析结果显示:金坑矿区黄铁矿的Co/Ni比值投点多数小于1,反映流体以变质热液为主;黄垢矿区的黄铁矿大致可划分为两类,其中产于细脉中的黄铁矿Co/Ni比值接近于0,为热液成因。As-Co-Ni图解显示金坑和黄垢矿区的黄铁矿主要成因类型为变质热液型,成矿温度应为中—低温。比较而言,金坑矿区黄铁矿中成矿指示元素(如Au、Ag、Cu、Pb、Zn等)含量较高且稳定,暗示金坑矿区比黄垢矿区更有利于形成中—大规模的金矿。总体上通道地区金矿剥蚀较浅,深部仍有很大的找矿前景。Tongdao county is located in southwest of Xuefeng arc structure belt,there are some small and medium-sized gold deposit such as Jinkeng deposit,Huanggou deposit and Chaxi deposit.Few research have done in this area,in order to discuss the genesis of gold deposit,this paper focuses on the genetic mineralogy study about pyrites of different occurrence.The macroscopic geological characteristics of the three deposits show that the wall rocks of the ore body are all low-grade metamorphic sandstone slate.Strong silicification alteration and fading alteration occurred in the surrounding rocks near ore-bearing quartz veins in Jinkeng mining area.The dip angle of quartz vein is steep in Huanggou mining area,and the tendency is southeast or northwest,the fracture filled with quartz vein is shear fracture.The ore bearing quartz veins in Chaxi mining area are mainly NW steeply dipping veins and their branch gently dipping veins.The gold orebodies are mainly quartz vein type or altered rock type.The ore contains pyrite,arsenopyrite and other sulfides.Generally,the ore vein with more pyrite content has a relatively high gold grade,suggesting that pyrite is the main gold-carrying mineral.Rock-mineral determination show that pyrite is mainly cubic and pentagonal dodecahedron and other semi automorphic granular in three gold deposit.MLA(mineral liberation analyzer)scanning results show that gold was produced in pyrite farcture or pyrite intergranular in Huanggou gold deposit.Major element results analyzed by EPMA show that the pyrites in general are rich in iron and deficient in sulfur,containing a small amount of arsenic.TheδFe-δS diagram shows that all points from three deposit concentrate in a narrow range,which is consistent with metamorphic hydrothermal gold deposit.Trace elements results analyzed by LA-ICPMS show that average Co/Ni value for Jinkeng pyrite samples is less than 1,which implies the fluid are from metamorphic water mainly.There are two kinds of pyrites in Huangou deposit,one produced in fine quartz vein,the

关 键 词：黄铁矿 成分标型 金矿床 矿床成因 通道地区 湖南省 

分 类 号：P618.51[天文地球—矿床学]