胶东马家窑金矿床流体包裹体及S同位素特征研究

Study on Fluid Inclusions and Characteristics of S Isotope in Majiayao Gold Deposit in Jiaodong Peninsula

摘要:

马家窑金矿位于胶东栖蓬福金成矿带盘马金矿田东部，本文针对该矿床主要成矿阶段典型矿石开展了流体包裹体及S同位素分析测试。研究表明，矿石中流体包裹体以纯液包裹体与富液体包裹体为主，局部发育富气体包裹体和H2OCO2三相包裹体，可见少量含子矿物富液体包裹体。包裹体均一温度集中于220～280℃，石英流体包裹体盐度（w（NaCl））集中于4.60%～8.60%，白云石流体包裹体盐度（w（NaCl））集中于5.14%～5.33%，流体密度集中于0.80～1.02g/cm3，估算成矿压力为200～285MPa，成矿深度约6.8～9.7km。矿石中黄铁矿δ34S值总体为5.3‰～15.9‰。成矿流体为中温、低密度、低盐度流体，具壳幔混合来源特征，矿床属中温中成热液矿床。

Abstract:

Majiayao gold deposit is located in the east of Panma gold field in QixiaPenglaiFushan gold metallogenic belt in Jiaodong Peninsula. In this paper, fluid inclusion and S isotope of typical ores in main metallogenic stages have been analyzed and tested. It is showed that the fluid inclusions in the ore are mainly pure liquid inclusions and rich liquid inclusions, gas rich inclusions and H2OCO2 threephase inclusions are developed locally, and a small amount of threephase inclusions with daughter minerals can be seen. The homogenization temperature of inclusions is concentrated in 220～280℃. The salinity of quartz fluid inclusions are concentrated in 4.60%～8.60%, but the salinity of dolomite fluid inclusions are concentrated in 5.14%～5.33%. The density of fluid is concentrated at 0.80～1.02g/cm3. The estimated metallogenic pressure is 200～285MPa, corresponding to the depth of 6.8～9.7km. The δ34S value of pyrite in the ore is generally 5.3‰~15.9‰. The oreforming fluid is a medium temperature, low density and low salinity fluid with the characteristics of crustmantle mixed source. Majiayao gold deposit belongs to a medium temperature and medium depth hydrothermal deposit.