投稿时间：2015-06-14
修订日期：2016-03-20
网络发布日期：2016-06-30
中文摘要:镰子沟金矿床是小秦岭驾鹿金矿田内的一个重要金矿床,赋存于太古宇太华群秦仓沟组深变质片麻岩系中,矿石主要为石英脉型。通过显微镜下观察和电子探针分析,确认矿石中存在碲金矿、斜方碲金矿、碲金银矿、碲银矿、碲铅矿、碲镍矿、自然碲等大量含碲矿物。在石英、黄铁矿裂隙中,也存在大量自然金颗粒,它们与硫化物、碲化物共生。结合不同成矿阶段的成矿温压条件和矿物组合研究,构建了该矿床的热力学相平衡关系图,限定了碲化物与其他矿物稳定存在的物理化学条件:即在成矿Ⅱ阶段,f(O2)约为10-34.00~10-31.00,f(H2S)约为10-1.42~10-0.9,pH值约为6.0~6.8(300℃)。在成矿Ⅲ阶段,f(S2)的范围约在10-16.56~10-12.30之间,而f(Te2)的范围约在10-13.70~10-9.44(200℃)。碲化物一般晚于硫化物形成,并且高的f(Te2)值和f(Te2)/f(S2)比值是控制碲化物形成的关键因素。
Abstract:The Lianzigou gold deposit is an important gold deposit in the Jialu gold orefield within the Xiaoqinling region. The deposit is hosted in the highly metamorphic gneiss which is the main rock type of the Qincanggou Formation of the Archean Taihua Group. Ores mainly occur as quartz-vein type. Detailed petrographic and electron microprobe analysis of ore minerals was carried out. Numerous tellurium minerals were identified, such as calaverite, krennerite, petzite, hessite, altaite, melonite and native tellurium. In addition, large amounts of native gold were recognized in the fractures in quartz and pyrite, coexisting with sulfides and tellurides. Physicochemical phase diagrams were established according to mineral assemblages, temperature and pressure conditions of different metallogenic stages in this study. Physicochemical conditions for the formation of tellurides and other minerals are as follows:f(O2)=10-34.00~10-31.00, f(H2S)=10-1.42~10-0.9 and pH=6~6.8 for stage Ⅱ (300℃), and f(S2)=10-16.56~10-12.30 and f(Te2)=10-13.70~10-9.44 for stage Ⅲ (200℃). Mineralogical investigation in this study indicates that tellurides formed later than sulfides, and high f(Te2) values and f(Te2)/f(S2) ratios were the two key factors that controlled the precipitation of tellurides.
文章编号：
中图分类号：P618.51;P618.83
文献标志码：
基金项目:本文系国家自然科学基金(编号:41573036)、高等学校博士学科点专项科研基金(编号:20130022110001)和国家重点基础研究发展规划(编号:2014CB440903)的部分研究成果
引用文本：
王雷,刘家军,朱文兵,代鸿章,刘冲昊,刘华南.2016.陕西小秦岭镰子沟碲金矿床物质组成特征及矿质沉淀机理研究[J].矿床地质,35(3):456~474WANG Lei,LIU JiaJun,ZHU WenBing,DAI HongZhang,LIU ChongHao,LIU HuaNan.2016.Mineral association and mechanism of mineral precipitation of Lianzigou gold-telluride deposit in Xiaoqinling gold orefield, Shaanxi Province[J].Mineral Deposits35(3):456~474
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