The wall rock alteration of Dashui gold deposit is intense and multi-stage.The main alteration types are silicification,hematite mineralization,and carbonation.Based on the geochemical characteristics of carbonate minerals in the Dashui gold deposit,the transformation relationship between magnetite and hematite,and the isoconcentration mapping method are used to discuss the relationship between wall rock alteration and mineralization of the deposit.It turned out that:the C of calcite in each stage of the deposit comes from the carbonatite of Middle Triassic Marresongduo Formation(T2m);the hematite is a kind of altered product,which is formed in the non-redox mode by the leaching of Fe2+from magnetite.The results suggested that:the Dashui gold deposit is not formed in an oxidizing environment,and the decarbonization-silicification+Au mineralization-calcite is a continuous and complete alteration-mineralization process.Porosity and permeability of the surrounding rock increased by decarbonization and hematitization,as a result,the migration of ore-forming fluids and the rate of water-rock reaction also improved;gold mineralization is closely related to magmatic activity.
关键词
西秦岭/大水金矿床/围岩蚀变/金矿化/成因类型
Key words
West Qinling/Dashui gold deposit/wall rock alteration/genetic type
维普
万方数据