湖南安化—桃江地区锑矿地质特征及找矿标志

Geological Characteristics and Prospecting Indicator of Sb Deposit in Anhua-Taojiang Area,Hunan Province

安化—桃江地区位于雪峰弧形构造带中东段,结合区内地质工作成果,对区内锑矿床地质特征、同位素地球化学特征、锑地球化学异常特征及控矿因素等进行了综合分析,划分了矿床成因类型,并对找矿标志及找矿方向进行了详细探讨。研究表明:(1)该区锑矿床成因类型有沃溪式层控热液型钨锑金矿、板溪式石英脉型锑矿,矿床主要赋存于前寒武纪冷家溪群、板溪群浅变质岩系内,其次赋存于南华纪—志留纪、泥盆纪—石炭纪碎屑岩及碳酸盐岩中;(2)锑矿多分布于区域性大断裂旁侧次级断裂与背斜交汇处,深断裂控制了金锑成矿带的展布,矿体主要产于NW组、NE组、近EW组、NNW组和NNE组次级断裂中;(3)矿区背斜或背斜倾伏端宏观控制了矿床的定位,背斜中的次级褶皱、断裂、层间破碎带及倾伏端等控制了矿体;(4)工作区浅成且酸性的小岩株、长英质脉岩可作为寻找锑矿的标志,Sb与Hg、As异常成密切正相关时,有利找矿,可利用金矿、砷矿(雄黄、雌黄)、汞矿等进行组合找矿。上述分析对于该区进一步研究成矿规律以及发现新的矿产地有一定的参考价值。

Anhua-Taojiang area is located in middle-east segment of Xuefeng arcuate structural belt,the scope of Sb geochemical anomaly area is large,and the anomaly peak value is high,the Sb metallogenic geological condition is favourable.Based on the geological prospecting results of the area,the geological characteristics,isotope geochemical characteristics and Sb geochemical anomaly characteristics and ore-controlling factors of the Sb deposits are analyzed,the deposits genesis types are classified,besides that,the prospecting indicators are summarized and the prospecting is discussed. The study results show that：（1）the Sb deposit types are Woxi type stratabound hydrothermal type W-Sb-Au deposit,Banxi type quartz vein type Sb deposit,the deposits are mainly hosted in the shallow metamorphic rock mass of the Lengjiaxi group and Banxi group of precambrian,the above deposits are mainly hosted in the clastic rock and carbonate rock of Nanhua period-Silurian and Carboniferous;（2）the Sb deposits are mostly distributed in the intersection area of the anticline and secondary fracture that is located in the side of the regional large fractures,the distribution of Au-Sb metallogenic belts are controlled by the deep fractures,the orebodies are originated from the NW,NE,nearly EW,NNW and NNE set of secondary fractures;（3） the deposits positioning is controlled by the plunging sides of anticline and anticline overally,the ore-bodies are controlled by the secondary folds,fractures,inter-layer fracture zones and plunging sides;（4）the little rock strain,felsic vein rock with the characteristics of hypabyssal and acidic in the working area can be regareded as the prospecting indicators of Au-Sb deposit,when Sb anomaly is closly related to Hg,As anomalies,it is good for prospecting,combination of prospecting work can be conducted based on Au,As（ realgar and orpiment） and Hg deposits. The above analysis results can provide some reference for the study of metallogenic regularities and the foundation of new mineralization points.