湖南康家湾铅锌多金属矿床地质地球化学特征与成因分析  

Geological and geochemical characteristics and genesis analysis of Kangjiawan Pb-Zn polymetallic deposit,Hunan

作　　者：欧阳志强 练翠侠 OUYANG Zhiqiang;LIAN Cuixia(Geological Team No.217 of Hunan Provincial Nonferrous Metals Geological Exploration Bureau,Hengyang 421001,Hunan,China)

机构地区：[1]湖南省有色地质勘查局二一七队

出　　处：《矿产与地质》2019年第3期419-426,共8页Mineral Resources and Geology

基　　金：全国危机矿山接替资源找矿项目(任务书编号:资〔2013〕01-036-047,项目编码:12120113083300)资助

摘　　要：康家湾铅锌多金属矿床位于湖南水口山矿田的东部,是矿田内最大的铅锌金银矿床,以铅锌为主,共伴生金银矿。通过硫、铅、氢-氧同位素研究,显示金属硫化物硫同位素δ34 S(-4.3‰^+2.1‰)主要变化范围为0^+3‰,说明本区硫化物硫同位素组成具有岩浆硫的特征(δ34 S=0‰);矿石铅同位素组成206 Pb/204 Pb、207 Pb/204 Pb、208 Pb/204 Pb比值分别变化于18.182~18.840、15.180~15.96、37.892~39.499之间,显示具有正常铅特点;在构造分配模式图解和构造环境判别图中,本区矿石铅同位素的投点均分布于上地壳演化线、造山带演化线和地幔演化线之间,暗示其铅同位素属于壳幔混合型铅;在Δγ-Δβ成因分类图解中,本区矿石铅同位素投点均分布于岩浆作用范围内,反映本矿床的成矿流体来源于岩浆岩;而氢-氧同位素表明,康家湾铅锌矿床成矿流体是多源的,主要由大气降水和岩浆水混合而成,早期以岩浆水为主,后期混入大量的大气降水。从而证明康家湾铅锌多金属矿床的形成与岩浆侵入活动有着密切的成因关系,应属于中低温岩浆热液型铅锌多金属矿床。The Kangjiawan Pb-Zn polymetallic deposit is located in the east of the Shuikoushan ore field,which is one of the largest Pb-Zn-Au-Ag deposit in the ore field with the main mineralization of Pb and Zn,accompanied by Au and Ag as well.Through the study of sulfur,Pb and H-O isotopic data,it is shown that the S isotopic value ofδ34 S of metal sulfides(from-4.3%to 2.1%)mainly varies from 0 to 3%.It is indicated that the S isotopic composition of sulfides in this area has the characteristics of magmatic sulfur(δ34 S=0).The ratios of 206 Pb/204 Pb,207 Pb/204 Pb,208 Pb/204 Pb vary from 18.182 to 18.840,15.180 to 15.96 and to 37.892 to 39.499,respectively.It is shown that the Pb isotopic composition of ore has the characteristics of normal lead.In the tectonic distribution pattern diagram and tectonic environment discrimination map,the input points of the Pb isotopes of ore in the study area are plotted between the upper crustal evolution line,the orogenic belt evolution line and the mantle evolution line.It is suggested that the Pb isotope belongs to crust-mantle mixture lead.On theΔγ-Δβore genesis classification diagram,the input points of Pb isotopic data of ores in the study area are plotted in the range of magmatism,It is considered that the ore-forming fluids of the deposit are derived from magmatic rocks.The H-O isotopic data indicate that the ore-forming fluids of the Kangjiawan Pb-Zn polymetallic deposit are multi-sources,and mostly blended by atmospheric precipitation and magmatic water,and magmatic water is dominant in the early stage,while abundant atmospheric precipitation is intervened in the later stage.It is proved that the formation of Kangjiawan Pb-Zn polymetallic deposit is closely related to the magmatic intrusive activities and should belong to the magmatic hydrothermal Pb-Zn polymetallic deposit of low-medium temperature.

关 键 词：康家湾铅锌多金属矿床 地球化学特征 硫、铅同位素 成矿流体 钦—杭结合带 

分 类 号：P618.42[天文地球—矿床学] P618.43[天文地球—地质学]