辽宁高家堡子银矿床流体包裹体研究

Fluid Inclusions in the Gaojiapuzi Silver Deposit,Liaoning Province

高家堡子银矿床经历了沉积变质期和热液叠加期。包裹体岩相学研究表明，沉积变质期不发育可供研究的流体包裹体，热液叠加期发育大量原生流体包裹体，其中石英黄铁矿阶段主要发育Ⅰ型气液两相、Ⅱ型含CO2三相、Ⅲ型单CO2及Ⅳ型单液相包裹体，包裹体均一温度为136～359C，盐度为3．1％～15．9％NaCl。成矿流体属NaCl-H2O-CO2体系；独立银阶段主要发育Ⅰ型气液两相和Ⅳ型单液相包裹体，包裹体均一温度、盐度分别为114～190℃，2．0％～5．5％NaCleq，属低温、低盐度NaCl-H2O流体体系。通过与矿区新岭岩体中流体对比研究发现，两者存在一定的相似性，表明成矿阶段流体主要来自岩浆热液，在成矿过程中，成矿流体经历了早期阶段不混溶作用到晚期阶段地下水的混合过程。流体的不混溶作用到混合过程对银的沉淀成矿产生了重要影响。

The Gaojiapuzi silver deposit underwent earlier sedimentation--metamorphism phase and later hydrothermal alternation phase. Detailed microthermometric studies and Laser Raman Spectroscopic analysis of fluid inclusions indicate that there are lots of primary fluid inclusions developed in the hydrothermal alternation phase, whereas hardly any in the sedimentation--metamorphism phase. There are four types of primary fluid inclusions in the quartz--pyrite stage： Ⅰ, two-phase aqueous, Ⅱ, three-phase carbon dioxide-bearing, Ⅲ, aqueous-phase carbon dioxide and IV, liquid only. The ore-forming fluids are of NaCl--H2O--CO2 immiscible hydrothermal system. Microthermometric studies indicate that the temperature, salinities and pressure vary from 136 to 359℃, 3.1% to 12.5% NaCleq, 82.0 to 142.0 MPa, respectively. The fluid inclusions in quartz from independent silver stage are mainly of types Ⅰ and Ⅳ, with lower homogenization temperature （110 to 190℃）, lower salinities（2.0% to 5.5% NaCleq） and lower pressure （8.83 to 15.57 MPa）. The ore-forming fluids belong to the NaCl-H2O fluid system. Comparing with the fluid inclusions of Xinlin pluton nearby, it can be concluded that the ore-forming fluids in the main stage derived from magma. In the ore-forming process, the ore-forming fluids underwent immiscible process to miscible process that brought positive influence on the concentration and precipitation of silver.