投稿时间：2014-04-23
修订日期：2015-03-05
网络发布日期：2015-09-02
中文摘要:广西天峨那弱银金矿床以银矿为主,共/伴生金及铅、锌、锑等金属,矿物组合在右江盆地内为首次发现。矿体受那弱背斜及其轴向断层控制,赋矿层位为中三叠统百逢组含钙质浊积岩系。矿石矿物以硫锑铅矿、铁闪锌矿、黄铁矿、毒砂和方铅矿为主;脉石矿物主要有石英、方解石、绢云母等。主要矿石矿物由早到晚的生成顺序为:毒砂→黄铁矿→铁闪锌矿→硫锑铅矿→方铅矿。单矿物化学分析显示硫锑铅矿含Ag最高,其次为闪锌矿;黄铁矿含Au相对较高。EPMA测试结果表明Ag于方铅矿中含量最高,其次为硫锑铅矿;主要矿石矿物中毒砂含Au相对较高,其余矿物中Au含量均偏低。因矿石中的铅矿物主要为硫锑铅矿,可以认为那弱银金矿床的Ag主要赋存于硫锑铅矿中,Au主要赋存于毒砂与黄铁矿中,二者均以显微-次显微状态赋存于载体矿物中。根据矿物组合及其相互交代、切割关系等特征,将矿床划分为2个成矿期共4个成矿阶段。其中,第一成矿期为金的成矿期,矿物组合为黄铁矿和毒砂,由于后期成矿作用的叠加,仅保留一个成矿阶段;第二成矿期为银铅锌成矿期,矿物组合为方铅矿-闪锌矿-硫锑铅矿;包含第二至第四共3个完整的成矿阶段。该矿床Ag、Au共生是不同期次成矿作用叠加的结果。
Abstract:Located in Tian'e County of Guangxi, the Naruo silver-gold deposit is a silver deposit associated with gold, lead, zinc and antimony. The special mineral assemblage was discovered for the first time in Youjiang basin. The orebody is controlled by Naruo anticline and its axial fault in Middle Triassic Baifeng Formation. The wall-rock is the calcic turbidite of basin facies. The main ore minerals include boulangerite, iron sphalerite, pyrite, arsenopyrite and galena, whereas the main gangue minerals are quartz, calcite and sericite. The generation sequence of ore minerals is in order of arsenopyrite, pyrite, iron sphalerite, boulangerite and galena. Chemical analyses of individual minerals reveal that boulangerite contains most of Ag, followed by sphalerite. The Au is relatively high in pyrite. EPMA test shows that the content of Ag is most abundant in galena, followed by boulangerite. The content of Au is most abundant in arsenopyrite. As the lead-bearing mineral is mainly boulangerite in ore, it can be inferred that Ag mainly occurs in boulangerite, whereas Au mainly occurs in arsenopyrite and pyrite. Both of Au and Ag occur in the mineral carrier in microscopic-submicroscopic state. According to mineral assemblages, cutting relationship of veins and replacement characteristics, two ore-forming periods consisting of four ore-forming stages were recognized in the deposit. The first period is gold mineralization with the mineral assemblage of pyrite and arsenopyrite, including only one ore-forming stage due to the late mineralization superposition. The second period is silver-lead-zinc mineralization with the mineral assemblage of galena, sphalerite and boulangerite, including the second to fourth ore-forming stages. The association of silver and gold in this deposit results from the superimposition of different ore-forming periods and stages.
keywords:geochemistry features of mineral assemblages modes of occurrence of silver and gold ore-forming periods and stages boulangerite Naruo silver-gold deposit western Guangxi
文章编号：
中图分类号：P618.51;P618.52
文献标志码：
基金项目:本文得到"广西自然科学基金项目(编号: 2012GXNSFAA053184)"和"国家重点基础研究发展计划973课题(编号: 2014CB440902)"联合资助
引用文本：
蒋柏昌,韦银泽,刘苏桥,刘融涛,杨锋.2015.桂西那弱银金矿床矿物组合特征及银和金的赋存状态研究[J].矿床地质,34(4):786~800JIANG BaiChang,WEI YinZe,LIU SuQiao,LIU RongTao,YANG Feng.2015.Mineral assemblages and modes of occurrence of silver and gold in Naruo silver-gold deposit, western Guangxi[J].Mineral Deposits34(4):786~800
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