广西大瑶山大裕金矿地质特征及找矿预测

Geological Characteristics and Prospecting Prognosis of the Dayu Gold Deposit in Dayaoshan,Guangxi

大裕金矿位于广西大瑶山成矿带的古袍成矿区带,构造单元属于桂中—桂东台陷大瑶山凸起东端古袍复式向斜南翼,矿区成矿地质条件优越,但由于对成矿规律认识不足,该区找矿工作推进缓慢。选取成矿带内典型的大裕金矿为例,在总结成矿地质特征的基础上,结合钻孔资料及镜下矿石特征,分析了该区金成矿的控矿因素和成矿规律,认为该区主要控矿构造为NEE向F1和F2断裂,赋矿围岩为寒武系小内冲组和黄洞口组浅变质含炭质细碎屑岩,矿化蚀变主要为硅化—黄铁矿化和绢云母化—黄铁矿化—硅化组合蚀变。研究提出该区今后找矿应结合物化探工作,重点找矿方向有:①关注与金成矿关系密切的硅化、黄铁矿化、绢云母(水云母)化及绿泥石化等围岩蚀变线索;②建议在NE-NEE向断裂及其所挟持部位和断裂交会部位开展找矿工作。

Dayu gold deposit is located in the Gupao metallogenic zone of the Dayaoshan metallogenic belt in Guangxi Province.The structural unit belongs to the Guizhong-Guidong platform depression,east part of Dayaoshan uplift,south part of Gupao compound syncline,where is favorable for mineralization.However,the prospecting work in this area has been restricted by the insufficient understanding of metallogenic regularity.In this paper,we studied the Dayu deposit as a typical deposit in the metallogenic belt.Based on the detailed analysis of the geological characteristics of the gold deposit,combined with the drilling data and the microscopic characteristics of the ore,the ore-controlling factors and metallogenic regularities of the gold mineralization in this area were analyzed.The main ore-controlling structures in this area are NEE-trending faults,F1 and F2,and the ore-bearing wall rocks are the Cambrian Xiaoneichong Formation and Huangdongkou Formation,which are mainly composed of shallow metamorphic carbonaceous fine clastic rocks.Wall rock alteration mainly includes silicification and pyritization or sericitization-pyritization-silicification combination alteration.It is suggested that the future gold prospecting works in this area should combine geophysical and geochemical exploration work,and it is necessary to pay attention to silicification,pyritization,sericite,hydromica,chlorite and other wall rock alteration that closely related to gold mineralization.It is proposed to carry out prospecting work at NE-NEE trending faults and its restricted areas as well as intersecting parts.