The Saidu gold deposit of Southern Altai, China: mineralizing stages and ore-forming fluids evolution

摘要

The Saidu gold deposit is located in the northwest part of Ertix Tectonic Zone in Xinjiang. The ore bodies occur in altered mylonite zones within the Mar-kakol giant fault zone and are controlled by the ductile shear zone. The structural-metallogenic fluids of the early stage are characterized by mesothermal-hydrothermal CO_2-N_2-rich fluids, with homogenization temperatures of fluid inclusions being 252～408°C. The tectonic-metallogenic fluids at the middle stage are characterized by CO_2-H_2O fluids, with homogenization temperatures being 203～326°C. The fluids at the late stage were epithermal-mesothermal low salinity aqueous solutions, with homogenization temperatures being 120～221°C. The main gold mineralization was related to the post-orogenic extension environment, with the evolution characteristics corresponding to the evolution of shear zones.