吴皓然, 谢玉玲, 王莹. 大别造山带汞洞冲铅锌矿床矿物学特征和铅同位素研究[J]. 地质通报, 2020, 39(2-3): 338-352.
    引用本文: 吴皓然, 谢玉玲, 王莹. 大别造山带汞洞冲铅锌矿床矿物学特征和铅同位素研究[J]. 地质通报, 2020, 39(2-3): 338-352.
    WU Haoran, XIE Yuling, WANG Ying. Mineralogical characteristics and Pb isotopes of Gongdongchong lead-zinc polymetallic deposit, Dabie orogenic belt[J]. Geological Bulletin of China, 2020, 39(2-3): 338-352.
    Citation: WU Haoran, XIE Yuling, WANG Ying. Mineralogical characteristics and Pb isotopes of Gongdongchong lead-zinc polymetallic deposit, Dabie orogenic belt[J]. Geological Bulletin of China, 2020, 39(2-3): 338-352.

    大别造山带汞洞冲铅锌矿床矿物学特征和铅同位素研究

    Mineralogical characteristics and Pb isotopes of Gongdongchong lead-zinc polymetallic deposit, Dabie orogenic belt

    • 摘要: 汞洞冲矿床位于大别造山带北麓,是以热液角砾岩型铅锌为主的多金属矿床。岩矿相显微鉴定、SEM/EDS及电子探针分析结果表明,矿床中Ag以独立银矿物相为主(硫锑铜银矿和含银黝铜矿),呈粒状、柱状、板状、不规则状等,以显微或亚显微状被包裹于先期形成的方铅矿中,金属硫化物中不可见银极少。结合矿床金属硫化物铅同位素结果表明,矿床的形成与燕山期岩浆活动密切相关,成矿物质具有壳幔混合的特征。自岩浆出溶的Pb、Zn、Ag等金属离子在成矿早期以氯络合物的形式迁移,随着成矿热液温度、盐度、fO2降低,以及pH值的升高,Pb、Zn氯络合物因稳定性降低而解体形成铅锌角砾型矿石,而Ag则形成硫氢络合物继续存在,当温度继续降低后发生分解沉淀,Ag+与Sb3+、As3+、Cu+结合形成大量独立银矿物。

       

      Abstract: The Gongdongchong Pb-Zn deposit, located on the north border of Dabie orogenic belt, Jinzhai County, Anhui Province, is a representative hydrothermal breccia-type lead-zinc polymetallic deposit in the Dabie Mountain region.The results of microscopic identification, SEM/EDS and EPMA of ore minerals indicate that silver exists mainly in the form of independent silver-bearing minerals, such as polybasite and Ag-tetrahedrite, which occur mainly in galena as micro-inclusions in the granular shape, columnar shape, lath shape and irregular form.The data 206Pb/204Pb (17.804~17.947), 207Pb/204Pb (15.567~15.669) and 208Pb/204Pb (38.496~38.886) of sulfides suggest that the ore-forming metals were derived from crust-mantle mixed source, being closely related to the Yanshanian magmatic activity.Metal ions such as Pb, Zn and Ag which were dissolved from magma migrate as chlorine-complex in the early stage of mineralization.As the temperature, salinity and fO2 dropped and pH rose, Pb, Zn-chloride-complex was decomposed to form a lead-zinc breccia ore due to the decrease in stability in the ore-forming hydrothermal solution, while the Ag-ions formed sulfur-hydrogen-complex.When the temperature fell, the Ag-sulfur-hydrogen-complex were decomposed and precipitated.Meanwhile, Ag+ combined with Sb3+, As3+, and Cu+ to form a large amount of independent silver-bearing minerals.

       

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