| The Qinshan gold deposit is located at the passive continental margin of Yangzi Plate and belongs to Zhen'an - Xunyang Strata distict. The outcropped Devonian and Carboniferous Strata is Parallel unconformity. The deposit is situated insouth of Xiaomoling ancient uplift,near the territorial deep-great faults of Zhenan-Banyan and Shanyang-Fengzhen, and located directly in the brittle fault structural zone stacked by the ore-bearing rock series in Lower Carboniferous on the sou-th of Haitangshan-Daping synclinorium.The ore bodys in the Qinshan gold deposit mainly occur in the lithological interface between Jiehejie and Jiuliping Formation. The two stratums which act as the roof and bottom of the ore bodys, both are not beneficial for the ore fluid's replacing. However, they play a good obstructing effect for the ore fluid's enrichment due to their high C,S as geochemical barrier.According to the compositions of the ore minerals, the ore can be divided into pyrite-type and limonite-type. The metal minerals are mainly siderite and pyrite of hydrothermal stage. Ore structures are brecciated, micro-disseminated, gelatineous, earthy, and the textures are automorphic-hypautomorphic granular, over-growth zoning, allotriomorphic granular, replacement remnant, pseudomorphic and strawberry. Gold mineral is included in pyrite and limonite as submicroscopic invisible gold. Wall-rock alteration is not rich, the main alteration is siliconization, pyritization, calcilization, ferritization, etc. According to the geological setting and geochemical characteristics, metallogenic evolution of the deposit is divided into hydrothermal sedimentation period, hydrothermal stage, supergene stage. Hydrothermal stage is the mainly metallogenic period.The trace elements and rare earth elements in ores indicate that mineralized components have inheritance from wall rock, metallogenic elements have the Au-Ag-As-Sb assemblage characteristics.The characters of hydrogen and oxygen isotopes, carbon isotope, and compositions of fliud inclusions indicate that the ore fluids are maily ore-forming fluid transformed by meteoric water which was strongly transformed by tectonism. Lead isotope possesses the feature of orogenic lead,this indicates lead come from orogenic settings and mineralizing dynamics came from the intracontinental orogenic action. Fluid inclusions in calcite had temperature from 153.6℃to 335℃,metallogenic depth was about 0.92km,belong to mid-hypabyssal, and metallogenic pressure was 270×105Pa. salinity was low(range from 9.93 to 6.45 NaCl equivalent wt percent). high sulfur fugacity(range from -11.25 to -16.96),low oxygen fugacity(range from -36.97 to -46.62),which belongs to relative reducing environment. In mineralizing processes, pH values was increasing gradually(range from 5.99 to 7.62).Gold metals were mainly migrated as bisulfide complexing,and deposited when the temperature and pressure changed.According to the above-mentioned geochemistry characters, Qingshan gold deposit should be the hot spring gold deposit, which is subtype of the epithermal deposit.
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