新疆东天山小石头泉地区琼库都克银多金属矿床成矿流体特征及其地质意义
Characteristics of OreForming Fluids and Their Geological Significance of Qiongkuduke Ag-Polymetallic Deposit in the Xiaoshitouquan Area of Eastern Tianshan Mountains, Xinjiang

琼库都克银多金属矿床位于新疆哈密地区的小石头泉矿区中部，是矿区目前为止最大的银多金属矿床，目前人们对该矿床的成矿机制研究有待深入.在详细矿床地质特征的研究基础上，开展了石英流体包裹体显微测温分析、群体包裹体的气液相成分分析以及稳定同位素(H、O同位素)分析.结果显示，琼库都克矿床的原生石英流体包裹体类型主要为富液相的水溶液包裹体，个体较小；成矿早期阶段(Ⅰ阶段)流体包裹体的均一温度变化于152～280℃，盐度ω(NaCleqv)变化范围为2.73%～13.50%；主成矿阶段(Ⅱ阶段)流体包裹体的均一温度变化范围为131～261℃，盐度ω(NaCleqv)变化范围为0.35%～9.59%，总体表现出中-低温、中-低盐度的成矿流体特征，从Ⅰ阶段到Ⅱ阶段，成矿流体的均一温度和盐度均有所降低，表明温度和盐度的降低可能为金属沉淀的成矿机制.流体包裹体的气相成分中绝大部分为H2O，其次含有一定的CO2，并含有少量N2以及CH4和C2H6等还原性气体；液相成分中阳离子主要为Na+、K+，阴离子以Cl-占绝大多数，部分含SO4 2-，表明琼库都克矿床的成矿流体富含挥发分，为H2O-NaCl型热液体系.主成矿阶段包裹体的δDH2O值范围为-89.5‰～-85.1‰，δ18ОH2O值为-8.671‰～-5.94‰，结合包裹体成分分析，显示矿床主成矿阶段的成矿热液为大气降水与岩浆水的混合来源.矿床地质特征、流体包裹体的研究结果以及氢氧同位素特征显示，琼库都克矿床为浅成低温热液型矿床.
Qiongkuduke Agpolymetallic deposit is located in the central Xiaoshitouquan area, eastern of the Harlik arc. The Qiongkuduke deposit is the largest Agpolymetallic deposit in the Xiaoshitouquan area. However, the mineralization mechanism of the deposit needs to be further studied. This paper focuses on the study of the homogenization temperature and the hydrogen and oxygen isotopic compositions of the fluid inclusions of the Qiongkuduke deposit based on the previous researches, to discuss the features of oreforming fluids source. It is found by systematically petrographic observations that fluid inclusions are mainly small, sparse, and aqueous. The homogenization temperature of fluid inclusions ranges from 152 to 280℃ and the salinity ranges from 2.73% to 13.50% NaCleqv in the early stage of mineralization (stage Ⅰ), and the homogenization temperature of fluid inclusions ranges from 131 to 261℃ and the salinity ranges from 0.35% to 9.59% NaCleqv in the main stage of mineralization (stage Ⅱ), indicating that the homogenization temperature and salinity of the oreforming fluid decrease from the early stage to the main stage of mineralization.The oreforming fluid belongs to the H2O-NaCl system with the gas phase mainly composed of H2O together with minor CO2 and N2, while the liquid phase is mainly composed of Na+, K+, Cl-together with minor SO42-. The hydrogen and oxygen isotopic compositions of fluid inclusions of the Qiongkuduke deposit show that the δDH2O value varies from -89.5‰ to -85.1‰ whereas the δ18ОH2O value varies from -8.671‰ to -5.94‰. Combined with the inclusion composition analysis, the oreforming fluid of the Qiongkuduke deposit is the mixture of magmatic water and atmospheric water. Regarding the regional tectonic setting, geological characteristics of the deposit, the features of oreforming fluids and the characteristics of isotope analysis, we conclude that the Qiongkuduke