Local geology of Dachang gold deposit was summarized simply according to detailed fieldworks and indoor researches. Based on microthermometic analyses of fluid inclusion, it was considered that metallogenic stages could be divided into poor mineralized quartz, quartz sulfide, quartz stibnite, visible-gold-bearing quartz and quartz calcite ones early and late. Poor mineralized quartz veins (metallogenic temperatures are about 350 degrees C, and homogenization temperatures are 280 similar to 360 degrees C), native-gold-quartz-sulfide cataclastic ores (metallogenic temperatures are about 301 degrees C, and homogenization temperatures are 220 similar to 280 degrees C), gold-quartz-stibnite ores (homogenization temperatures are 160 similar to 220 degrees C), and native-gold-quartz veins (homogenization temperatures are 160 similar to 220 degrees C), formed respectively in the former four stages, and little silicification and carbonification (homogenization temperature is lower than 160 degrees C) could happen in the above four types of rocks or ores during the latest quartz calcite stage. Accompany with Laser Raman spectrum analyses, it was concluded that the metallogenic fluids underwent low salinity H2O-CO2-NaCl fluid system in lithostatic pressure system (metallogenic pressure is 215MPa, metallogenic depth is 8.1km) in the early stage, low salinity H2O-NaCl fluid system in lithostatic to hydrostatic pressure system (metallogenic pressures are 49 similar to 108MPa, metallogenic depths are 5.5 similar to 8.6km) in the middle stage and low salinity H2O-NaCl fluid system under hydrostatic pressure system (metallogenic pressures may be low than 40MPa) in the latest stage, respectively. Finally, the author thought the genetic type of Dachang gold deposit belongs to epizonal to mesozonal orogenic gold deposit.
