马来西亚吉兰丹州安曼金矿床流体包裹体研究

Fluid inclusion of Amon gold deposit in Kelantan of Malaysia

基于安曼金矿床地处马来西亚半岛吉兰丹州西南部,矿体呈脉状赋存于二叠—三叠系浅变质火山—沉积岩系内,并受断裂控制。对安曼金矿床流体包裹和群体成分进行研究。研究研究表明：安曼金矿床各成矿阶段金矿石中主要发育CO2-H2O包裹体及气液两相H2O包裹体,早期阶段主要以CO2-H2O包裹体为主,主成矿阶段CO2-H2O包裹体及气液两相H2O包裹体均有发育,后期多为气液两相H2O包裹体。成矿流体的均一温度、盐度在早阶段分别为248-352℃和1.6%-8.8%,主成矿阶段分别为185-336℃和0.43%-11.6%,晚阶段分别为118-226℃和2.9%-5.1%;包裹体气相成分以H2O和CO2为主,并含有少量CH4和H2;包裹体液相成分中阳离子以Na^＋,K＋和Ca^2＋为主,阴离子以Cl^-,SO4^2-和F^-为主。据沸腾包裹体群的均一温度推测主成矿阶段成矿温度为230-326℃。安曼金矿床成矿流体总体表现为低盐度、富CO2的中低温流体,主成矿阶段流体不混溶作用引起成矿流体中的CO2相分离是促使金沉淀的直接因素。安曼金矿床形成与二叠—三叠纪时期马来半岛中缅马苏陆块和印支陆块间的碰撞造山机制有关,属于造山型金矿床。

Considering that Amon gold deposit is located in the southwest of Kelantan state of Malaysia, and that its ore deposit controlled by the faults is located in the Permian—Triassiac volcanic sedimentary rock series, the fluid inclusions,the properties and evolutions of ore-forming fluid were studied. The results show that these fluid inclusions from gold ores of each metallogenic stage are dominated by CO2-H2 O fluid inclusion and liquid-vapor two-phase H2 O fluid inclusion. In early stage, fluid inclusions are mainly CO2-H2 O fluid inclusion, the homogeneous temperatures vary from 248 ℃ to 352 ℃, and the corresponding salinities of this stage range are from 1.6% to 8.8%. In main metallogenic stage, fluid inclusions are dominated by CO2-H2 O fluid inclusion and liquid-vapor two-phase H2 O fluid inclusion, the homogeneous temperatures vary from 185 ℃ to 336 ℃, and the corresponding salinities of this stage range from 0.43%to 11.6%. In late stage, fluid inclusions are mainly liquid-vapor two-phase H2 O fluid inclusion, the homogeneous temperatures vary from 118 ℃ to 226 ℃, and the corresponding salinities of this stage range from 2.9% to 5.1%. The gas component of fluid inclusions is dominated by CO2 and H2 O, and also has little CH4 and H2. The positive ions in fluid inclusions are mainly Na＋, K＋ and Ca2＋, and the main negative ions are Cl-, SO2- 4and F-. The homogeneous temperature of the inclusion groups shows that the metallogenic temperature is 230-326 ℃ in the main metallogenic stage. The ore-forming fluid of Amon gold deposit belongs to low salinity, rich CO2 and mid-temperature fluid system, and the fractionation of CO2 from the ore-forming fluid caused by the fluid immiscibility in main metallogenic stage is the major factor controlling gold precipitation. The formation of Amon gold deposit is related to the mechanism of collisional orogenesis between Sibumaso continental block and Indochina continental block from Permian to Triassic, which belongs to orogenic gold deposit.