辽宁高家堡子大型银矿床流体包裹体特征及矿床成因

Characteristics of fluid inclusions and origin of Gaojiapuzi silver deposit,Liaoning Province.

高家堡子银矿床为辽东地区近年来发现的一大型独立银矿床,它赋存于早元古代辽河群大石桥组大理岩地层之中,受层间破碎带构造控制。矿区发育含银-铅-锌碎裂大理岩型及硅化石英脉型两种主要类型矿石。流体包裹体研究表明,前者石英中主要发育气液两相、含 CO_2三相、CO_2及单液相四种类型的原生流体包裹体,成矿流体属 H_2O-CO_2-NaCl 体系类型,与造山型矿床成矿流体相似;后者石英中主要发育气液两相及单液相包裹体,成矿流体属 H_2O-NaCl 体系类型,其低温低盐度特点及氢、氧同位素数据表明成矿流体主要来自大气降水。综合分析表明,本区银的大规模富集成矿作用是印支期以来以大气降水来源为主的热液活动的产物。

The Gaojiapuzi silver deposit is a large silver-dominated deposit that has been discovered in eastern Liaoning Province in recent years. It occurs in marble strata of the Dashiqiao Formation, Liaohe Group of Early Proterozoic Era and is contolled by interbedded brecciation fractures. There are two kinds of ores developed in the mining district, which are silver-lead-zinc-bearing brecciated marble type and silicified quartz vein type respectively. Systematic study on fluid inclusions reveals that there are four types of primary fluid inclusions existed in quartz of the former kind of ores, which are two-phase aqueous, three-phase CO2-bearing, pure CO2 and single phase aqueous fluid inclusions respectively, the mineralization fluids are of H2O-CO2-NaCl type and similar to those of orogenic type of deposits. In quartz of the later type of ores, two-phase aqueous and single phase aqueous are the dominated kinds of fluid inclusions, the ore-forming solutions are of H2O-NaCl type and the low temperature, low salinity characteristics, combined with hydrogen and oxygen isotope data support that this kind of ore-forming solutions are mainly of meteoric water. Comprehensive analysis showed that the large-scale Ag enrichment is mainly the result of the activities of H2O-NaCl type fluids. So it is concluded that Gaojiapuzi silver deposit was formed by meteoric-derived hydrothermal fluids at Indo--Chinese epoch.