Abstract: Nirich pyrites, FeS₂-Fe（Ni,Co）S₂ whisker series and VL inclusions occur in giant barite crystals discovered in Gengzhuang gold deposit, Shanxi Province. The morphology, component and physical characteristics of barite and solid inclusion are studied by means of SEM and microprobe etc. The component, homogenous temperature of VL inclusions are researched through Laser Roman. The results indicate that the barites are pure and their structures are excellent. The component of FeS₂-Fe（Ni，Co）S₂ whisker series changes with the thickening of the whiskers. The component of Ni-rich pyrite is stable. The crystalline of solid inclusions is good with standard crystal shape. The hydrothermal liquid is of low sanity, and the component mainly is H₂O with little CO₂, and the general density is 0.79～0.95 g／cm³. The homogenous temperature varies greatly, i.e., 134.7～269.5℃. Combined the results above with the geological setting, the hydrothermal activity, the geochemical behaviors of the related elements, the forming conditions of barite and solid inclusions are discussed using the theories of crystal growth and geochemistry. Boiling and blending of the hydrothermal fluids are of great importance and multiple stages and insitu overlapping are believed to be a major features of the hydrothermal activities in the Gengzhuang gold deposit.

Key words: Gengzhuang gold deposit, barite, Nirich pyrite, whisker, inclusion