湘中古台山金(锑)矿床地质特征及成因探讨

Geological characteristics and genesis of the Gutaishan gold-antimony deposit in central Hunan

湘中古台山金(锑)矿床位于江南造山带湖南段雪峰弧形构造带西南段,处于龙山—白马山EW向隆起带、城步—新化NE向断裂带以及郴州—邵阳NW向基底隐伏大断裂交汇地带,是湖南著名的石英细脉型金(锑)矿床。通过总结矿床地质特征,分析控矿因素,归纳矿化富集规律,浅析矿床成因,得到以下结论:区内发育有走向NWW、倾向相反的两组金(锑)矿脉。以倾向NNE的3号矿脉为主,为蚀变破碎带型金(锑)矿脉;倾向SSW的金(锑)矿脉为3号断裂多期次构造活动中的次级构造,为裂隙充填型金(锑)矿脉;各矿体均与NNE向F 1断裂关系密切,具有明显的侧伏规律,且矿体具有明显的分段富集特征;矿床成矿物质来源于岩浆流体与基底变质热液相互作用的混合流体;矿床发育特征不同的单金矿脉和金(锑)矿脉,赋存于不同方向的构造中,空间上共生,为两期成矿,即单金矿脉形成于印支成矿期,金(锑)矿脉形成于燕山成矿期。

The Gutaishan gold-antimony deposit in central Hunan is located in the southwestern section of the Xuefeng arc tectonic belt in the Hunan section of the Jiangnan orogenic belt.It is located in the intersection of the Longshan-Baimashan EW-trending uplift zone,the Chengbu-Xinhua NE-trending fault zone,and the Chenzhou-Shaoyang NW-trending basement concealed large fault zone.It is a famous quartz veinlet type gold-antimony deposit in Hunan.By summarizing the geological characteristics of the deposit,analyzing the ore-controlling factors,summarizing the mineralization enrichment law,and analyzing the genesis of the deposit,the following conclusions are obtained:two groups of gold-antimony veins with NWW trend and opposite tendency are developed in the area.It is dominated by No.3 vein tending to NNE,which is an altered fracture zone type gold-antimony vein;the gold-antimony vein inclined to SSW is a secondary structure in the multi-stage tectonic activity of No.3 fault,which is a fracture-filled gold-antimony vein.The ore bodies are closely related to the NNE-trending F 1 fault,with obvious lateral regularity,and the ore bodies have obvious segmentation enrichment characteristics.The ore-forming materials of the deposit are derived from the mixed fluid of magmatic fluid and basement metamorphic hydrothermal interaction.The single gold veins and gold-antimony veins with different development characteristics of the deposits occur in structures in different directions and are spatially symbiotic.They are two-stage mineralization,that is,the single gold veins are formde in the Indosinian metallogenic period,and the gold-antimony veins are formed in the Yanshanian metallogenic period.