海沟金矿流体包裹体为3种类型:富CO2三相、气液两相和纯气相.流体盐度集中在7.44％～8.67％ NaCleqv,8.54％～8.94％ NaCleqv和9.84％～10.87％NaCleqv三个区间；流体密度为0.54 ～0.88 g/cm3；成矿温度主要集中在298.4～313.5℃和258.2～264.6℃.研究表明成矿早期阶段流体为低盐度、富CO2的高温流体,且富CO2型和富气相包裹体共存.成矿中晚期阶段流体盐度和温度明显降低,CO2、H2O等气体能够大量逃逸,流体体系由封闭状态转化为较开放状态,大气降水、层间水等大量进入与岩浆流体发生混合,并引起流体内金络合物的溶解度减小而直接导致金和金属矿物的沉淀和富集.成矿压力范围为110～146 MPa,成矿深度为8.7～10.1 km.通过与典型的造山型金矿特征对比,该矿床成因类型为中成造山型金矿,动力学背景为早-中侏罗世华北板块与西伯利亚板块碰撞的持续汇聚力和古太平洋板块俯冲欧亚大陆的作用力引起的远程效应联合作用的结果.%The three types of fluid inclusions in Haigou gold deposit include those of the three-phase ( gas-liquid- solid) rich in CO2, two-phase (gas-liquid) and pure gas. The salinities of fluid inclusions concentrated in three ranges of 7. 44%～8. 67% , 8. 54%～8. 94% and 9. 84%～10. 87% of NaCleqv, and the densities of fluid inclusions range from 0. 54～0. 88 g/cm3. The homogenization temperatures of fluid inclusions concentrated in two ranges of 298. 4℃～313. 5℃ and 258. 2℃～264. 6℃. The study shows that: during the early ore-forming stage, the ore-forming fluids are characterized by high temperature, low salinity, coexisting CO2-rich three phase and pure gas phase. In the middle-late ore-forming stage, the ore-forming fluids are characterized by falling in temperature, reducing in salinity. Abrupt falling of temperature results in C02 and H2O loss, and the fluid system changes into opening system from closed system. The solubility of gold complexes from fluids reduces to cause precipitation of gold and other metal minerals because atmospheric water, interlayer water mixed with magma fluid. The ore-forming pressure is 110 ~ 146 Mpa, the ore-forming depth is 8. 7 ~ 10. 1 km. Contrasted to other orogenic gold deposits,the Haigou gold deposit is defined as mesozonal orogenic gold deposit. Two kinds of forces, the post-collisional lasting convergent force of North China Plate and Siberia Plate, and the other force from paleo-Pacific Plate subduction to Eurasian continent formed the metallogenic dynamic background of Haigou gold deposit during Early-Middle Jurassic.
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