Gold Occurrence And Discussion On Genesis Of Jinying Gold Deposit In Baishan

The Jinying gold deposit located in Baishan city,Jilin province of southeastern China, whose geotectonic position laid in the eastern sector of the northern margin of the Sino-Korean platform, the sunken side of the interface between Tieling-Jingyu promontory and Taizi river-Hunjiang river concave. Faults were the main ore-controlling factors.In this paper, Jinying gold deposit was chosen as the research target, gold distribution in ore minerals and the relationship between the content of gold and gold-bearing mineral were studied by means of second electron graphs with scan electron microscope and energy-dispersive X-Ray spectrometer. The results indicated that Jinying gold deposit was simple material composition and could be classified into low-sulfide type. The main gold-bearing mineral was quartz.The type of mineral ore was silicificated breccia and structural breccia mainly. Aurum occurred as nature gold, silver-bearing nature gold and electrum, inter-granular gold and inclusions were the main occurrence forms. The size of gold minerals was fine, the configuration of gold minerals were graininess and kernel, as well as with high fineness.Meanwhile, the fluid inclusion geochemistry, together with geology characters, was studied also. Fluid inclusions in quartz were gas-liquid type in general and with the shape of oblate or anomalistic. Less sole-liquid or sole-gas types could be seen. By data calculation and determination of fluid inclusions, the physical and chemical conditions of ore-forming were found out:the ore-forming temperature was about 139.6℃to 235℃, pressure from 33.6to 65.6MPa, fluid salinity from 1.74% to 4.65% (NaCl).The transformation of Au in ore-forming fluids was mainly in the form of [AuH3SiO4]0. Rock and water reaction, the mixing of fluids, and temperature and press lowing down probably may be a valid depositional mechanism of Au from the ore-forming fluids of Jinying gold deposit.Above all, the deposit was considered as a low to moderate temperature hydrothermal type deposit.