Geological Characteristics And Mineralization Of Shengligou Gold Deposit, Qinghai Province

The Shengligou gold deposit is located in northern Qaidam orogenic and metallogenetic belt, which is characterized by its complicated tectonic settings and favorable ore-forming conditions. Based on detailed field study of geological features, wall rock alteration characteristics, and ore-controlling structures, combined with trace elements, REEs, stable isotopes, and fluid inclusions, the geologic structure background, ore genesis and mineralization mechanism have been discussed in this research.Ore bodies are controlled by alteration fracture zone, while mineralization is enriched inhomogeneously, discontinuously. The types of ores are mainly quartz-metal sulfide, which replaced and filled fractures.It is inferred that the ore lead mainly derived from crust, especially upper crust, in accordance with narrow range of lead isotope values and diagrams of lead isotope compositions.Two phase aqueous inclusions have been distinguished pervasively based on petrographic observation. The ore-forming fluids is characterized by mid-low temperature, with low density, while the salinities range from3.06to13.62%, with a certain portion of data showing higher salinities. Thus, the ore-forming fluids are conceived to originate from the metamorphic Dakendaban Group, combined with a small amount of deep seated magmatic hydrothermal. The estimated ore-foeming pressures is about80-160MPa, and the mineralization depth is7～10km.In conclusion, Mineralizing hydrothermal was migrated upwards along the large-sized shear zone and secondary faults in a long distance, with metallogenic elements leached constantly from surrounding rocks simultaneously.to form gold-bearing fluids. The gold deposit were deposited and formed after ore-forming fluids was transferred to the northwest secondary fracture, with the transformation of the structuralcharacter and the variation of physical and chemical condition simultaneously. This kind of metallogenesis is similar with the regional orogenic gold deposit.