ZHANG Rong-zhen1, ZHANG De-hui1, LI Jian-kang2*, ZHAO Bo1, HOU Hong-xing3, HUANG Cheng1, YU Xiao1, SUN Xi-de1
1. School of Earth Sciences and Resources, China University of Geosciences(Beijing), Beijing 100083, China;
2. Institute of Mineral Resources, China Academy of Geological Sciences, Beijing 100037, China;
3. No.6 Gold Geological Party of CAPF, Sanmenxia Henan 472000, China
Abstract: This paper systematically studied on geology and ore-forming fluids in the Shiyaogou molybdenum deposit and discussed the nature and evolution of the ore-forming fluids. According to the crosscutting relationship of ore veins, the hydrothermal ore-forming process can be divided into early, middle and late stages, in which the characterized mineral assemblages of the hydrothermal ore-forming fluid were quartz-potash feldspar-molybdenite-pyrite, quartz-polymetallic sulfides and quartz-calcite±pyrite, respectively. There four types of fluid inclusions, NaCl-H2O, pure CO2, CO2-H2O and daughter mineral-bearing fluid inclusions were found in the quartz of the early and the middle stages, while only one type of fluid inclusions, NaCl-H2O inclusions, were found in the quartz of the late stage. Microscopic date, including compositions, homogeneity temperature and salinity, of fluid inclusions from different stages demonstrated that the early stage ore-fluids were characterized by high temperature, high salinity and high content of CO2, the middle stage ore-fluids underwent a rapid precipitation of ore-forming materials since of fluid boiling and CO2 releasing, and the late stage ore-fluids were characterized by low temperature, low salinity and low content of CO2. It implied that the fluid boiling process might be the dominant factor for molybdenite deposition.
Keywords: Shiyaogou molybdenum deposit fluid inclusion ore-forming fluid fluid boiling
*Corresponding Author, E-Mail: li9968@126.com
Bulletin of Mineralogy, Petrology and Geochemistry Vol. 34, No.1, 2015, page 167-176
