Uranium Occurrence State and Its Implication for Sandstone-Type Uranium Mineralization within the Hanbazhai Area of the Longchuanjiang Basin, China

The Mangbang Formation in the Hanbazhai area is part of uranium ore field Longchuanjiang Basin, China. Uraniferous sandstones from this formation are examined study. type and mode occurrence investigated detail using an experiment for sequential extraction uranium, as well electron probe, scanning microscopy, energy spectrum analyses. indicates that proportion minerals significantly greater than adsorbed samples, with latter being largely present framboidal pyrites clay minerals. results show these mainly composed coffinite phosphosilicates, which closely coexist pyrites, carbon debris, feldspar minerals, discovery phosphosilicates discussed context their symbiotic relationship geochemical environment. considered to have undergone at least two stages mineralization: sedimentary–diagenetic stage later enrichment by fluid. environment generally a sulfide-reducing environment, fluids rich U, Si, P, Y.