云南会泽铅锌矿床闪锌矿化学成分特征及其指示意义

A typomorphic study of sphalerite from the Huize lead_zinc deposit, Yunnan Province

在详细的野外调研及岩相学研究基础上,通过电子探针分析（EMPA）和电感耦合等离子体质谱分析（ICPMS）,系统研究云南会泽铅锌矿不同成矿阶段闪锌矿化学成分特征,探讨Zn、Fe、Cd、Ge、In、Ag的富集规律及其指示意义。研究表明,该矿床的热液成矿作用可划分为4个阶段,依次为细粒黄铁矿阶段、多金属硫化物阶段、黄铁矿-方铅矿阶段和碳酸盐阶段,其中闪锌矿的形成可划分为两个阶段,从早到晚颜色由黑色变为红色。早阶段闪锌矿富Fe,贫Ge、In、Ag、Zn和Cd;晚阶段闪锌矿富Ge、In、Ag、Zn和Cd,相对贫Fe。闪锌矿中Cd、Ge等有用组分均已达到工业综合利用要求,主要替代Fe进入闪锌矿晶格。闪锌矿中Fe S含量从早到晚呈降低趋势,估算早期成矿温度为170-262℃,晚期成矿温度低于203℃,结合Zn/Cd含量比值变化范围,认为该矿床属于中温热液矿床,其成矿温度由早至晚逐渐降低。空间上,Zn、Fe含量及Zn/Cd值均指示矿床形成时热液由深部向浅部流动。将该矿床闪锌矿中In、Cd、Ga、Ge、Zn/Cd、Ga/In、Ge/In等特征元素及其比值与典型铅锌矿进行对比,显示会泽铅锌矿与MVT型铅锌矿床类似。

In this paper, the authors conducted a systematic study of the features of chemical components of different stages of sphalerite in the Huize lead-zinc deposit by using electron microprobe analysis （EMPA） and ICP- MS, so as to explore enrichment regularity and indicative significance of Fe, Zn, Cd, Ge, In and Ag. The results show that hydrothermal metallogenesis of the Huize deposit can be divided into four ore-forming stages, forming fine-grained pyrite, polymetallic sulfides, pyrite-galena and carbonate respectively. Sphalerite can be di- vided into two generations varying in color from black to red gradually. The early stage sphalerite exhibits en- richment of Fe and depletion of Zn, Cd, G-e, In and Ag. In contrast, the late stage sphalerite shows relative depletion of Fe and enrichment of Zn, Cd, Ge, In and Ag. The content of Cd and Ge has met the requirement of comprehensive utilization, and these two elements are mainly in the form of isomorphism in the sphalerite. Oreforming temperatures range from 170 to 262℃ at the early stage and below 203℃ at the late stage, as shown by the content of FeS in the sphalerite. In combination with the sphalerite Zn/Cd ratios, it is suggested that the Huize lead-zinc deposit is a mesothermal deposit. Spatially, the flowing direction of the hydrothermal fluid was consistent with the strike of the orebodies. Compared with typical lead-zinc deposits, the In, Cd, Ga, Ge, Zn/Cd, Ga/In and Ge/In of sphalerite in the Huize lead-zinc deposit show characteristics of Mississippi valley-type deposit.