Relationship between Uranium Minerals and Pyrite and Its Genetic Significance in the Mianhuakeng Deposit, Northern Guangdong Province

Granite-related uranium ore is an important resource type in China and worldwide. Whether the geochemical theory “U6+ oxidative migration U4+ reductive precipitation” applicable to granite-related mineralization has not been determined. Detailed field petrographic work, as well scanning electron microscopy energy spectrum analysis, are conducted this study analyze relationship between minerals pyrite from different types evaluate mechanism for precipitation enrichment of Mianhuakeng deposit northern Guangdong. Uranium bodies generally occur vein-filling or vein-disseminated types. Four kinds ores recognized: fluorite, carbonate, siliceous, reddening Despite differences mineral assemblages, veined share similar characteristics show that (1) central part periphery interphase arrangements with syn-ore quartz, calcite veins; (2) veinlets disseminated cataclastic altered granite; (3) inlaid gangue minerals, primarily calcite, microcrystalline quartz; (4) closely associated aggregates relatively independent states, forming straight boundaries have euhedral intact crystals mosaic growth features. All these results indicate both co-crystallized products ore-forming fluid. Combined previous research suggesting reducing fluid was sourced mantle, shows decreased pressure temperature, changes pH solubility (saturation) changes, rather than redox reaction, caused deposit.