江西永平铜矿闪锌矿原位微量元素特征与矿床成因  

In situ trace elements of sphalerite from Yongping copper deposit in Jiangxi province:Implication for the ore genesis

作　　者：石得凤 李桂贤 朱云 颜青 刘建平[3] 孙琳 SHI De-feng;LI Gui-xian;ZHU Yun;YAN Qing;LIU Jian-ping;SUN Lin(School of Earth Sciences and Spatial Information Engineering,Hunan University of Science and Technology,Xiangtan 411201,China;The Tenth Geological Brigade of Jiangxi Geological Bureau,Yingtan 335000,China;Key Laboratory of Metallogenic Prediction of Nonferrous Metals and Geological Environment Monitoring of Ministry of Education,Central South University,Changsha 410083,China)

机构地区：[1]湖南科技大学地球科学与空间信息工程学院,湖南湘潭411201 [2]江西省地质局第十地质大队,江西鹰潭335000 [3]中南大学有色金属成矿预测与地质环境监测教育部重点实验室,湖南长沙410083

出　　处：《矿物学报》2023年第5期653-664,共12页Acta Mineralogica Sinica

基　　金：国家自然科学基金青年项目(编号:42102083);江西省煤田地质局2021年科研项目;湖南省教育厅一般项目(编号:20C0766)。

摘　　要：江西永平铜矿是钦杭成矿带东部重要的大型W-Mo-Cu多金属矿床,针对该矿床的深入细致的元素地球化学研究尚有不足,严重限制了对矿床成因类型及成矿过程的认识。本文采用LA-ICP-MS原位分析技术,对矿体内广泛存在的闪锌矿进行微区原位微量元素组成分析,为矿床成因类型研究提供新的资料和制约。研究结果表明,永平铜矿内的闪锌矿相对富集Fe、Mn、Cu、Cd元素,In、Co、Ni、Ga含量次之,Ag、Se、Pb、Bi、Te含量较低。其中Fe、Cd、Mn、In、Ag、Ni等元素主要以类质同象形式赋存在闪锌矿内,而Cu、Pb、Bi则有类质同象和微粒包体两种赋存形式。闪锌矿的Cd/Fe值(0.033~0.20)、Cd/Mn值(0.62~4.15)和Zn/Cd值(多数小于250)揭示成矿过程与花岗质岩浆关系密切;闪锌矿的Fe元素含量(1.1%~9.4%)、Ga/Ge值(2.0~340.6)、Ga/In值(0.01~7.00)、Zn/Cd值(135.5~318)均指示闪锌矿形成于中温成矿条件(约208~289℃之间)。与国内多个典型矿床相比,永平铜矿闪锌矿微量元素含量较集中,这一特征明显不同于MVT型矿床;Fe、Cd元素含量明显低于SEDEX型和VMS型矿床,Fe、Mn、Ag、Co、Sb等元素的组成与矽卡岩型矿床高度吻合。永平铜矿应属于矽卡岩型矿床,闪锌矿Fe含量截然不同的2类矿石应该分别形成于石英-硫化物成矿期的早、晚2个阶段。The Yongping copper deposit,located in the eastern part of the Qinhang mineralization belt,is an important large-scale Wu-Mo-Cu polymetallic deposit in Jiangxi province.The lack of detailed studies of element geochemistry on this deposit limits the understanding of ore genesis and metallogenic process.In this paper,LA-ICP-MS in situ analysis technique was used to analyze the trace elements composition of sphalerite vastly existing in the ore body,then provided new data and constraints for the ore genesis study of Yongping copper deposit.The results show that the sphalerite in Yongping copper deposit was relatively enriched with Fe,Mn,Cu and Cd,followed by In,Co,Ni and Ga,the contents of Ag,Se,Ni,Pb,Bi and Te are low.Among them,Fe,Cd,Mn,In,Ag,Ni are mainly exist in the form of isomorphism,while Cu,Pb and Bi have two forms of deposition:isomorphism and particulate inclusion.The values of Cd/Fe(0.033-0.20),Cd/Mn(0.62-4.15)and Zn/Cd(mostly less than 250)of sphalerite reveal that the mineralization process is closely related to granite magma.The content of Fe in sphalerite(1.1%-9.4%),the values of Ga/Ge(2.0-340.6),Ga/In(0.01-7.00),Zn/Cd(135.5-318)all indicate that sphalerite was formed under medium temperature mineralization conditions(about 208-289℃).Compared with multiple deposits in China,the trace element content of sphalerite in Yongping copper ore is relatively concentrated,which is obviously different from MVT-type deposits,the content of Fe and Cd is significantly lower than typical SEDEX-type and VMS-type deposits,and the composition of Fe,Mn,Ag,Co,Sb and other elements is highly consistent with skarn-type deposits,implying that they have the same genesis type.Yongping copper ore should be skarn deposit,two types ore with different Fe content in sphalerite should be separately formed in the early and late stages of quartz-sulfide mineralization period.

关 键 词：闪锌矿 微量元素 LA-ICP-MS 成矿条件 矿床成因 永平铜矿 

分 类 号：P611.1[天文地球—矿床学]