Relationship between the hydrogeochemical environment and sandstone-type uranium mineralization in the Ili basin, China

This paper describes the occurrence and distribution of U within groundwater of the Ili basin in Xinjiang, China. Dissolved major ions, dissolved gases, pH, Eh and salinity in groundwater were employed to distinguish different hydrogeochemical environments and associated processes affecting U transport within the aquifer. The results show that dissolution and deposition of U by groundwater are closely related to reactions with organic C and minerals such as sulfides, carbonates and silicates along groundwater flow paths. Different chemical reactions predominate and account for changes in the occurrence of U in the rock and water of the oxidized zone, the redox transition zone, and the reduced zone. Knowledge of these associations between U and hydrogeochemical environments could enhance the understanding of relationships of groundwater circulation and U mineralization and could have implications for prospecting for sandstone-type U deposits.

Research highlights► We explore the relationship of U in groundwater to the hydrogeochemical environment. ► We integrate hydrogeochemical parameters to characterize the hydrogeochemical zones. ► U speciation and behavior in groundwater are different in different zones. ► U in groundwater is dissolved and transported as U(VI) in the oxidized zone. ► U in groundwater is precipitated and mineralized as U(IV) in the redox transition zone.