Located in the west of Li-Min metallogenic belt, western Qinling Mountains, the Zhaishang gold deposit is newly found as a large micro-disseminated gold deposit in this early century. Two main types of fluid inclusions, namely aqueous inclusions and CO2 hearing inclusions are recorded in quartz and calcite hypothermal veins. Final homogenization in two-phase fluid inclusions occurs between 110 and 300 degrees C with most of the ore-forming temperatures around 240 degrees C. Salinities (7.18% on average) represent reverse correlation with fluid temperatures as it increase in hypothermal fluids system from early to late stage, which indicates a boiling event. Calculated densities of hypothermal fluids concentrate in the range of 0.8 similar to 1.0g/cm(3). The Zhaishang gold deposit is partly not similar to other adjacent gold deposits since it has a higher pressure and deep depth. Fluid inclusions analyses show that H2O, CO2 are main compositions of gas phase, with minor of N-2, CH4; Na+, Ca2+, anion SO42- and Cl- are dominating in liquid phase, with minor of other cation and NO3-, F-. All these data demonstrate a "brine-CO2-CH4" ore-forming fluids combination with moderate to low temperature, low salinity, low density and rich organic compositions. Based on characteristics, evolution associated with the ore-forming fluids of the Zhaishang gold deposit, we believe that deep origin (magmatic and/or metamorphic) hypothermal fluids may take a more important role in gold activation, though structural transition leads to the gold and sulfides precipitation by changing the conditions of the primary well-evolved fluids.
