关键词: 成矿流体, 预富集, 流体分异, 成矿模式, 寨上金矿, 西秦岭

Abstract:

Zhaishang gold deposit is a micro-fine disseminated gold deposit.Au occurred in three types:micro-fine grained inclusions or isomorphism existed in gold bearing minerals；micro-fine grains distributed among debris particles;as micro-fine grains found in quartz and calcite crystals.Gold-bearing pyrite has characteristics of proliferative zones;primary ore types mainly include disseminated ore and fine-stockwork ore,and very little massive ore.Deposit types are fine-medium disseminated fracture zone type and fine-stockword type.Microthermometry study shows that ore-forming fluid has characteristics of low temperature,low salinity,low densities,multi-period,low pressure and shallower depth.It can be concluded from gold occurrence state,proliferative zones of gold-bearing mineral, ore type,deposit type and ore-forming fluid composition and characteristics,that gold mineralization of Zhaishang deposit is controlled by dual role of structure and fluid.Thereby establishing a mineralization model for Zhaishang Au deposit:substances of shallow depth and deep depth origins mix to form ore-forming fluid→ore-forming fluid differentiation→penetration→form vein type (disseminated) ore.

Key words: Ore forming fluid, Preconcentration, Fluid differentiation, Mineralization model, West Qinling, Zhaishang gold mine