广西昭平湾岛金矿的成因:流体包裹体和HOSPb同位素地球化学约束
Genesis of the Wandao Gold Deposit in Guangxi, China：Evidences from Fluid Inclusions and HOSPb Isotopes

摘要： 湾岛金矿是近年来广西东南部大瑶山多金属成矿集中区古袍金矿田内发现的中型矿床，其物质来源及成因尚存在较大分歧。根据详细的坑道及岩矿相学观察，将湾岛金矿成矿分为2期3阶段：钨钼铜金成矿期和金主成矿期(分为金主成矿阶段和金晚成矿阶段)。石英流体包裹体显微测温和激光拉曼光谱分析表明，金主成矿期成矿流体为中高温、低盐度、低密度的含CO2和CH4流体。氢氧同位素分析表明，金主成矿期成矿流体中水主要为变质水，钨钼铜金成矿期成矿流体中水可能为岩浆水及变质水的混合。矿石矿物硫同位素数据显示，钨钼铜金成矿期硫同位素值为小的正值，可能为深源硫；金主成矿期湾岛矿区硫同位素组成变化范围大而均值较小，推测钨钼铜金成矿期成矿物质来源以深源硫为主；金主成矿期为岩浆硫与地层硫的混合硫。初步认为湾岛金矿属于变质-岩浆热液叠加改造成矿。
Abstract: The Wandao gold deposit, located in Gupao ore field of Dayaoshan polymetallic metallogenic clusters area in the southeastern Guangxi, is a mediumsized ore deposit discovered in recent years. The source of oreforming substance and ore genesis are still under debate. There is still a big difference between its material origin and genesis. Based on detailed observation in underground tunnel and petrographic study under microscope, the Wandao gold deposit can be divided into WMoCuAu mineralization period and main gold dominated mineralization period. Furthermore, the main gold dominated mineralization period can be divided into main stage and late stage. Microscopic temperature measurements and Laser Raman Spectra analysis of fluid inclusions in quartz indicate that the oreforming fluids of main gold dominated mineralization period in the Wandao gold deposit are fluids with high temperature, low salinity, low density and containing CO2 and CH4. Hydrogen and oxygen isotope analysis data of quartz indicate the oreforming fluids of main gold dominated mineralization period mainly derived from metamorphic water, and the oreforming fluids of WMoCuAu mineralization period is the mixture of magmatic water and metamorphic water. The small positive value of sulfur isotope for WMoCuAu mineralization period infers that sulfur come from magma reservoir in depth. Whereas, small average with large range of sulfur isotopic composition for gold dominated mineralization period suggests that the sulfur in ore probably mainly derived from strata and partly from magmatic rocks. Based on the above analysis, it is considered that the Wandao gold deposit belongs to metamorphic and magmatic hydrothermal superimposed deposit typ