【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、f_O2降低,以及p H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。更多还原

【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 f_O2 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.更多还原