湖北徐家山锑矿床流体包裹体特征及其意义

Characteristics of fluid inclusions in Xujiashan antimony deposit of Hubei Province and its implications

文章利用激光拉曼光谱和显微测温学方法,对湖北徐家山锑矿床成矿期的石英、重晶石和方解石中的流体包裹体进行了研究。研究表明,这些矿物中的流体包裹体主要有纯液体包裹体和液体包裹体（气相＋液相）2类,其液体包裹体的气相成分为H2O±CO2±N2;石英、重晶石和方解石的均一温度分别为134-258℃、154-259℃和145-230℃,主要集中于150-200℃;流体的盐度w（NaCleq）和密度分别集中于3%-6%和0.90-0.96g/cm^3。流体包裹体资料揭示出该矿床为典型的中低温热液锑矿床,其成矿流体为中低温、低盐度、中等密度热液。结合H、O、Sr、Pb同位素等研究结果,进一步推断该成矿热液主要是经深部循环演化的大气降水。

The Xujiashan antimony deposit is located in Tongshan County, Hubei Province, and its antimony mineralization occurs in marine carbonates of Upper Sinian Doushantuo and Dengying Formations. Microthermometry and laser Raman spectroscopy were used to study fluid inclusions in such gangue minerals associated with antimo- ny mineralization as quartz, barite and calcite. There are two types of inclusions observed at room temperature in the studied minerals, namely liquid and liquid-vapor inclusions. Laser Raman spectrometric analysis shows that gaseous components of the liquid-vapor inclusions are mainly H2O and subordinately CO2 and N2. Homogenization temperatures of liquid-vapor inclusions in quartz, barite and calcite range from 134℃（2 to 25812, 15412 to 25912 and 14512 to 23012, respectively, mostly concentrated between 150 and 20012. The calculated salinities and densities of fluids mainly fall in the range of 3 % -6 % NaCl equivalent and 0.90-0.96 g/cm^3, respectively. These fluid inclusion data indicate that the ore-forming fluid of the Xujiashan antimony deposit is characterized by low-moderate temperature, low salinity and moderate density.. Combined with H, O, Sr and Pb isotopes data, it is held that this fluid should be deep circulating meteoric water.