Characteristics On Typomorphic Minerals And Fluid Inclusions In The Shanhou Gold Deposit,Jiaodong Peninsula

The Shanhou gold deposit is located in the border zone of Laixi city and Zhaoyuan city, Jiaodong Peninsula. This paper chose some samples of wall rocks and ores from Shanhou gold deposit to discuss the geological structure and material source according to the study of petrology, major and trace elements, rare earth elements, fluid inclusions, typomorphic characteristics of main minerals, combining with previous research on the geotectonic setting geochemistry and ore genesis.The wall rock alterations in Shanhou gold deposit are developed, such as phyllic alteration, silicification, potassic alteration, while pyritization and sericitization have close relationship with gold mineralization. According to the mineral assemblage and formation sequence of the Shanhou gold deposit, we can divide the ore forming stage into 4 stages: I pyrite- quartz stage, IIgold- quartz- pyrite stage, III gold- quartz- polymetallic sulfide stage, IV quartz- carbonate stage.Gold mainly exists in the form of electrum and gold, according to the study of gold minerals; The micro-fine gold is the main gold mineral grain size, accounted for 95%; Its shape is rounded granular, angular grains, wheat grains, like tree branches, leaf-shaped and so on; Occurrence of gold minerals is mainly crystal interface gold, fissures gold, inclusions gold.S/Fe ratios in pyrite are lower than 2, most of samples Co/Ni ratios are higher than 1, a small amount of samples are lower than 1, the Au/Ag ratios are much higher than 0.5, ω(As) > 1500 × 10-6 in pyrite, all above illustrate the mineralization of Shanhou gold deposit is involved in magmatic hydrothermal.Compared with the southern section of Zhaoyuan-Pingdu mineralization belt, obvious pyrite loss S and similar variation range in mineralization stage, states that the metallogenic mechanism and source of ore-forming materials are basically identical of the gold ore in the southern section of Zhaoyuan-Pingdu mineralization belt.Granite, silky mica-quartzite granitic cataclasite and pyrite phyllic cataclasite enriched rare earth elements. Variety compositions characteristics of the REE indicate similarity and it has the same evolution direction. It reflects that silky mica-quartzite granitic cataclasite and beresitization cataclasite in ore deposit genesis have close relation, the metallogenic fluid may derive from same source at a certain extent.According to the research of the fluid inclusions in the quartz of Shanhou gold deposit, the homogenization temperature of fluid inclusions in II mineralization stage is mainly concentrated in 160~240°C, and the homogenization temperature of fluid inclusions in III mineralization stage is mainly concentrated in 140~200°C; The salinity of the ore-forming fluid is concentrated in 2~10wt%NaCl; the density of the ore-forming fluid is mainly from 0.77 to 0.98 g.cm-3; The depth of ore-forming is from 4.8-7.5km, and the mean value is 5.7km; The pressure of ore-forming is from 37.2-83.5MPa, and the mean value is 52.2MPa. So, we can infer that Shanhou gold deposit is a low salinity, low density, medium temperature, medium pressure and middle-deep gold deposit.