Ore-forming mechanism of Xiajinbao gold deposit in Pingquan, Hebei based on fluid inclusions and stable isotopes
(1. Key Laboratory of Metallogenic Prediction of Non-ferrous Metals and Geological Environment Monitoring, Ministry of Education, Central South University, Changsha 410083, China;
2. School of Geosciences and Infophysics, Central South University, Changsha 410083, China;
3. China Nonferrous Metals Resource Geological Survey, Beijing 100012, China)
2. School of Geosciences and Infophysics, Central South University, Changsha 410083, China;
3. China Nonferrous Metals Resource Geological Survey, Beijing 100012, China)
Abstract: The Xiajinbao gold deposit is located in Yong’an—Xiayingfang—Maojiagou polymetallic metallogenic belt, which is an important metallogenic belt in North China block. In this paper, we present a detailed study on fluid inclusions and stable isotopes of the Xiajinbao gold deposit, Hebei Province, China, aiming at discussing the ore source, evolution of ore-forming fluid and ore-forming mechanism of the deposit. The macroscopic geological characteristics, S and Pb isotopic analysis results show that the source of ore-forming materials is mainly from granitic magma, and subordinately from country rocks. H and O isotopic composition features indicate that the ore-forming fluid is mainly derived from magmatic water. Fluid inclusion characteristics show that the ore-forming fluid experienced boiling during the early mineralization stage, which led to the precipitation of gold. Fluid mixing dominated the precipitation of the ore-forming materials during the middle and late stages. The gold precipitation was caused by water/rock reaction throughout the whole ore-forming process.
Key words: fluid inclusion; stable isotopes; ore-forming source; ore-forming mechanism; Xiajinbao gold deposit