DU Ze-zhong1,2, YE Tian-zhu2,3, PANG Zhen-shan2,3, LV Zhi-cheng2,3, LIANG Wan-juan1,2, ZHEN Shi-jun1,2, ZHANG Zhi-hui1,2,3, LI Yong-sheng2,3, ZHEN Shi-min2,3
1. School of Earth Sciences and Resources, China University of Geosciences(Beijing), Beijing 100083, China;
2. Technical Guidance Center for Mineral Resources Exploration, Ministry of Land and Resources, Beijing 100120, China;
3. Research and Development Center, China Geological Survey, Beijing 100037, China
Abstract: The Baiyinchang mine-field is located in the east of massive sulfide deposits metallogenic province in Qilian Mountain area. The orebody is hosted in early-middle Cambrian assemblage of baschtauite and spilite. According to the study on the metallogenic fluid characteristic from the vein orebody at the footwall of Zheyaoshan deposit, this paper discusses the metallogenic mechanism, the nature and origin of ore-forming fluid. The petrography and microthermometric results of fluid inclusions in ore-bearing quartz show the inclusion types are liquid inclusion, gaseous inclusion, pure gaseous inclusion, CO2-bearing three-phase inclusion and pure CO2 inclusion. Respectively, the homogenization temperature of the first stage inclusions is concentrated between 201~413℃ while the salinity(NaCl) is on 1.43%~13.40%, as of the second stage inclusions is concentrated between 217~428℃ while the salinity (NaCl) is on 1.91%~11.93%. The composition in fluid inclusions indicates that the gases in fluid inclusions are chiefly composed of H2O, and the secondary components are CH4, CO2. The cations inclusions are dominanted by Na+ while the anions by Cl-. The ore-forming system is H2O-NaCl-CO2-CH4 system. The ore-forming fluid from the footwall vein orebody of Zheyaoshan deposit is the mixture of magmatic fluid and the heated sea water, and the ore-forming material derives from mixing of fluids.
Keywords: fluidinclusion characteristic copper polymetallic Zheyaoshan deposit Baiyinchang Gansu
