| The barite deposit in Salang of Duyun, Guizhou, is located in the South anticline of Wangsi. Its regional stratigraphy includes Lushan Formation(?3l) of Cambrian; Tongzi Formation(O1t), Honghuayuan Formation(O1h), Dawan Formation(O1d) of Ordovician; Ordovician; Wengxiang Group(Swx) of Silurian; Bangzai Formation(D2b) of Devonian. Base on the inclusion research in Salang barite deposit, The microthermometry, compos- ition of the fluid inclusions and the H-O isotopes were obtained, The soruce and fluid properties of the ore-forming fluids, and metallogenic mechanism of barite reources we- re discussed in this study.(1) The petrography characteristics of the fluid inclusions in from Hydrothermal period show that inclusions are composed of liquid inclusions and pure liquid inclusions.(2) The results of Fluid-inclusions microthermometry show that the homogenization tempreture is about 95.3~239.8?, average being 149?; the salinity is about 0.5~22.9 wt%(Na Cl eqv), average being 6.7 wt%(Na Cl eqv); the density is aboat 0.81~1.08g/cm3; average being 0.96g/cm3. the metallogenic pressure is about 5.97~12.13 Mpa, average being 8MPa. the mineralization depth is about 0.19~0.4Km, averge being 0.27 Km.(3) The composition analysis of the fluid inclusions shows that gas composition mainly is H2 O, secondly for CO2; Liquid ion composition mainly are Ca2+,Na+,Cl- and SO42-. The ore-forming fluids mainly is a Ca2+-Na+-Cl--SO42- type of water in Salang bari- te deposit.(4) The H-O isotopes suggest that the O isotpes for barite vary from 0.58‰ to 12.05‰, average being 6.87‰, H isotpes is ranges from-48~-38‰, average being-44.3‰. The O isotpes for calcite vary from-1.15‰ to 10.3‰, average being 3.87‰, The ore-forming fluid is mainly for Atmospheric precipitation.(5) The analysis of the C isotopes shows that the C isotpes for calcite vary from-1.9~-1.0‰, It is speculated that the C may be derived from marine carbonate.(6) Atmospheric precipitation cycle and extraction along fractures, which formed mineral-rich hydrothermal fluids, which leads to the change of physical and chemical properties, causing the precipitation with Ba mineral. |
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