云南东川雪岭铜多金属矿区硫铅同位素组成特征及成矿物质来源  

Characteristics of S and Pb isotope compositions and source of metallogenic material in Xueling Cu-polymetallic mining area of Dongchuan, Yunnan

作　　者：刘文恒[1] 刘继顺[1] 马慧英 刘卫明[3] 吴自成[1] 许亚男[4] 

机构地区：[1]中南大学地球科学与信息物理学院教育部有色金属成矿预测重点实验室,湖南长沙410083 [2]湖南省地质调查院,湖南长沙411100 [3]江西理工大学资源与环境工程学院,江西赣州341000 [4]东华理工大学研究生院,江西南昌330013

出　　处：《中南大学学报（自然科学版）》2014年第8期2728-2739,共12页Journal of Central South University:Science and Technology

基　　金：云南省三年地质找矿计划项目(Z2010004)

摘　　要：雪岭矿区位于东川断隆与禄劝断坳结合部,灯影组赋矿以黄铁矿、黝铜矿、辉铜矿为主,含少量的方铅矿、闪锌矿等,深部陡山沱组赋存有滥泥坪式铜矿床,对雪岭矿区和东川矿区相应层位的金属硫化物样品中的硫和铅同位素进行分析。研究结果表明:灯影组和陡山沱组金属硫化物δ34SV-CDT分别为-37.5‰^+27.4‰和-1.5‰^+19.5‰,显示硫主要来源于海相硫酸盐的还原作用,并受到不同硫源的混染,与落雪组和因民组所含金属硫化物δ34SV-CDT相似;铅同位素组成落点位于上地壳附近和上地壳与造山带之间,并具相关性,说明灯影组矿石铅来源于壳幔混合,成矿物质主要来源于深部陡山沱组和昆阳群铜矿床,部分来自围岩;灯影组样品模式年龄为260~350 Ma,推测矿化应是受峨眉山玄武岩喷溢热动力影响导致陡山沱组和昆阳群成矿物质活化并沿断裂带运移至浅部沉淀富集;含矿热液沿途还原沉积地层的海相硫酸盐,围岩提供部分成矿物质。Xueling mining area is located in the intersection of dongchuan fault-uplift and Luquan fault-depress。The minerals in Dengying formation are pyrite, tetrahedrite, chalcocite and some galenas and sphalerites, the Lanniping type copper ore deposit occurred in the deep Doushantuo formation, S and Pb isotopic compositions of the metal sulfides of the corresponding formation in the Xueling mining area and Dongchuan mining area were studied. The results show that the δ34SVCDT of metal sulfides in Dengying formation and Doushantuo formation vary from-37.5‰ to ＋27.4‰ and-1.5‰ to ＋19.5‰, respectively, which is similar to those in Luoxue formation and Yinmin formation, indicating that sulfur mainly comes from marine sulfate reduction, and is intermingled with different sulfur sources. The Pb isotopic compositions of all samples are plotted not only near the Upper Crust belt evolution curve, but also in the region between the upper crust and the Orogenic, and there is a significant positive correlation between them, which indicates that Pb of the metal sulfides in Dengying formation can be derived from a mantle-crust mixed source, and the metallogenic material is mainly from the copper deposit of deep Doushantuo formation and Kunyang group, partly from the surrounding rocks. The model age of samples in Dengying formaion is from 350 Ma to 260 Ma, the Cu-polymetallic mineralization in Dengying formation results from the deep metallogenic material of Doushantuo formation and Kunyang group activate under the influence of thermal power of the Emeishan basalt spurting, and then migrates along faults and enriches in the shallow strata. The sulfur in ore-bearing hydrothermal solution mainly comes from marine sulfate of sedimentary strata reduction, and the surrounding rocks provide part of the metallogenic material.

关 键 词：硫同位素 铅同位素 成矿物质来源 东川矿区 雪岭 

分 类 号：P597.2[天文地球—地球化学]