湖北保康六冲坪金矿流体包裹体特征及成矿机理探讨

Fluid Inclusion Characteristics and Metallogenic Mechanism of Liuchongping Gold Deposit in Baokang Country,Hubei Province

六冲坪金矿为黄陵背斜北翼沉积盖层中发现的第一个金矿,对鄂西上扬子地层区寻找金矿具有重要指示意义。为揭示其成矿流体的性质和来源,对金矿流体包裹体进行了岩相学观察、显微测温和碳氢氧同位素测试分析。结果表明,矿石中流体包裹体以两相盐水溶液包裹体为主,其次是单相盐水溶液包裹体,成矿流体总体属于中低温、低盐度、中低密度流体,同时具多期热液活动特点。成矿流体总体属于NaCl-H_(2)O体系,成矿压力为135.4×10^(5)~192.8×10^(5) Pa,成矿深度为0.451~0.643 km。δD、δ^(18)O、δ^(13)C稳定同位素研究表明,成矿流体具大气降水、岩浆热液多来源特点,且与沉积地层联系密切。六冲坪金矿成矿受物源、热源、水源、围岩、断裂构造等多因素联合控制。

Liuchongping gold deposit in Baokang County,Hubei Province is the first gold deposit discovered in the sedimentary cover of the north wing of the Huangling anticline,which is of great significance for the prospecting of gold deposits in the upper Yangtze platform of western Hubei.Petrographic observation,micro-temperature measurement and hydrocarbon-hydrogen isotope test are carried out on the gold inclusion fluid inclusions in order to reveal the nature and source of the ore-forming fluids of the deposit.The results show that the fluid inclusions in the ore are mainly two-phase saline solution inclusions,followed by single-phase saline solution inclusions.The ore-forming fluids generally belong to medium-low temperature,low salinity,medium-low density fluids,and have the characteristics of multi-phase hydrothermal activity.Ore-forming fluids generally belong to the NaCl-H_(2)O system.The metallogenic pressure is 135.4×10^(5)~192.8×10^(5) Pa,and the metallogenic depth is 0.451~0.643 km.δD,δ^(18)O,andδ^(13)C stable isotope studies indicate that ore-forming fluids have multiple sources of atmospheric precipitation and magmatic hydrothermal fluids,and are closely related to sedimentary strata.The metallogenesis of Liuchongping gold deposit is controlled by multiple factors including source,heat,water,surrounding rock and fault structure.