湖南石门雄黄矿床流体包裹体地球化学特征

石门超大型雄黄矿床流体包裹体丰富。包裹体液相成分中富Ｎａ＋、Ｃｌ－和Ｋ＋、ＳＯ２－４，气相成分中Ｈ２Ｏ占绝对优势，少量ＣＯ２，成矿流体化学类型属Ｃｌ ＳＯ４ Ｎａ Ｋ型水。雄黄、雌黄形成于低温（１８０～９０℃）、低压（２０～５ＭＰａ）、浅成（１７５～７００ｍ）、弱酸性（ｐＨ：４．６７、４．４３）和弱还原（Ｅｈ：－０．２６５Ｖ）条件。流体包裹体氢氧同位素研究表明，成矿流体主要为古大气降水，并混有盆地建造水，大气降水下渗、循环、加热、淋滤形成了中－低盐度［ｗ（ＮａＣｌ）：１６．０３％～４．２７％］，中等密度（０．８６３～１．０６５ｇ／ｃｍ３），含矿地下热水。

GEOCHEMISTRY OF FLUID INCLUSIONS ASSOCIATED WITH THE REALGAR DEPOSIT IN SHIMEN,HUNAN

The super large sized realgar deposit in Shimen,Hunan,is distinguished by numinous fluid inclusions consisting of liquid phase rich in Na +,Cl -,K + and SO 4 2- and vapor phase comprised of prevailing H 2O and lesser CO 2. Mineralizing fluids fall chemically into a Cl SO4 Na K type water whose precipitations as reagar and orpiment needed lower temperature (180～90℃),lower pressure(20～5MPa),smaller depth (175～700m), slighter acidity (pH:4.67, 4.43) and slighter reduction (Eh=-0.265V). H and O isotopic studies of fluid inclusions suggest that the mineralizing fluids were made up chiefly of paleometeoric water, later mixed with a certain amount of basin formational water and that they could become ore bearing hydrothermal solutions characteristic of low moderate salinity [ W (NaCl)= 16.3% ～ 4.27% ) and moderate density (0.863～1.065g/cm3) only after downward percolating, convecting, being heated and being leaching.