| Abstract:The Bangbule deposit in is located in the western section of the Gangdise metallogenic belt, in Xizang, is a newly discovered large skarn lead-zinc deposit. Magnetite is widely developed in the deposit, and its texture and chemical composition characteristics are of great significance for revealing the physical-chemical conditions of ore formation and the evolution of ore-forming fluids. This study focuses on different generations of magnetite in the Bangbule deposit, conducting mineralogical observations and electron microprobe analysis to reveal their texture and compositional characteristics. The results show that magnetite in the Bangbule deposit can be divided into two generations: MagⅠ is mostly filled in the gaps of pyroxene grains, and chemically it is characterized by high Mn content; MagII is associated with quartz and has a low overall Mn content. The chemical composition of magnetite is characterized by high Mg, Al, Ca, Mn, and low Ti, which is typical of skarn deposits with hydrothermal origins. In addition, from MagⅠ to MagII, the ore-forming fluid has experienced a transition from high oxygen fugacity and low water-rock ratio conditions to low oxygen fugacity and high water-rock ratio conditions, formation environments are relatively stable at medium to high temperatures. This study has constructed a fluid evolution model for the magnetite formation process in the Bangbule deposit, which is indicative of the fine delineation of the metallogenic fluid evolution process in the Bangbule deposit, systematic analyses of the relationship between magnetite chemical elements and deposit genesis also provide data sources and constraints for intelligent mineral search and machine learning. |
