桐柏──大别地区中温热液金矿床成矿流体性质与沉淀机理  

ORE-FORMING FLUIDS IN MESOTHERMAL GOLD DEPOSITS OF TONGBO-DABIE AREA:THEIR PROPERTIES AND PRECIPITATION MECHANISM

作　　者：徐启东[1] 钟增球[1] 索书田[1] 齐先茂 

机构地区：[1]中国地质大学,鄂东北地质大队

出　　处：《矿床地质》1995年第1期59-72,共14页Mineral Deposits

摘　　要：通过对桐柏─大别地区１０个中温热液金矿床（点）的流体包裹体研究，确定成矿流体属于低盐度（６ｗｔ％ＮａＣｌ）、富ＣＯ＿２（１０ｍｏｌ％）的Ｎａｃｌ－ＣＯ＿２－Ｈ＿２Ｏ体系。这种以演化的大气降水为主的流体在４～１０ｋｍ深度范围内，由于压力由静岩压力状态向静水压力状态的突变而发生的复杂三阶段不混溶过程中沉淀，在该过程的中晚期出现金矿化。压力状态的突变是柏桐─大别造山带在中生代碰撞造山晚期，由挤压体制向伸展体制转换抬升隆起作用的结果。Fluid inclusion studies of ten mesothermal gold deposits (occurrences ) in Tongbo- Dabie area show that the ore-forming fluids are of the NaCl-CO_2-H_2O system with low salinity(6 wt%NaCl) and rich CO_2 ( 10 mol%).At the depth of 4 ～ 10 km,the fluids dominated by evolutionary water precipitated during the complex three-stage immiscible process which took place due to the sudden change of pressure from the lithostatic pressure state to the hydrostatic pressure state, and gold mineralization occurred at the late stage of this process. The sudden change of the pressure state resulted from the uplifting of the Tongbo-Dabie orogenic belt at the late stage of Mesozoic collision orogeny when the deformation system of this belt transformed fromthe compression state to the extension state.

关 键 词：金矿床 成矿流体 液包体 热液 沉淀机理 

分 类 号：P618.510.5[天文地球—矿床学]