OJG  Vol.5 No.11 , November 2015
Characteristics of Fluid Inclusions and Metallogenesis of Annage Gold Deposit in Qinghai Province, China
Abstract: The Annage gold deposit is located at the east part of the eastern Kunlun orogenic belt. The characteristics of ore-forming fluids and metallogenesis were discussed by using fluid petrography, micro-thermometry and hydrogen-oxygen isotope analysis. Three stages, namely quartz-pyrite stage (A), quartz-polymetallic-sulfide stage (B) and quartz-ankerite stage (C) were included in the hydrothermal process as indicated by the results of this study. Inclusions developed in ore-bearing quartz veins from stages A and B are of three types: aqueous inclusions (type I), CO2-bearing inclusions (type II) and pure CO2 inclusions (type III). All three types of inclusions, mainly type I, are presented in stage A, having homogenization temperatures at 180°C - 360°C, and salinities ranging from 0.53% to 21.44%. In addition to development of type I inclusions, type II and III inclusions increase significantly in stage B, with homogenization temperatures ranging from 160°C to 330°C, and salinities are from 1.32% to 22.01%. Based on micro-thermometry, fluids in Annage deposit are of H2O-NaCl-CO2 type with medium-high temperature (140°C - 395°C) and medium-low salinity (0.53% - 22.01%). Results of hydrogen-oxygen isotope analysis show that ore-forming fluid is mainly CO2-rich magmatic fluid, mixed with shallow groundwater or metamorphic hydrothermal in the late mineralization stages. Calculated metallogenic pressures are in the range of 79 - 130MPa corresponding to a maximum depth of 4.8 km. The Annage deposit is a mesothermal quartz vein type gold deposit.
Cite this paper: Lai, J. , Ju, P. , Tao, J. , Yang, B. and Wang, X. (2015) Characteristics of Fluid Inclusions and Metallogenesis of Annage Gold Deposit in Qinghai Province, China. Open Journal of Geology, 5, 780-794. doi: 10.4236/ojg.2015.511067.

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