Unconformity-related Uranium Deposit

Required Geological Setting

Paleogene and older sediments

Occurrence

Uranium deposits hosted by sedimentary rocks unconformably overlie fluvial sandstone. Deposits are considered to be formed in Proterozoic (1300-1600 Ma), 50-250 My after formation of the unconformity. Most of deposits are massive or layered, and are associated with such metasomatic minerals as hematite, sericite, calcite, dolomite, and kaolinite. This type of deposits is usually high quality and produces 0.2-1.5 % U₃O₈. The formation process of deposits is considered as follows: Methane is produced by reaction of graphite in the hosts with oxidative water formed by diagenetic processes, and uranium minerals are deposited by reaction of this methane-rich hydrothermal fluid with uranium-rich oxidative water.

Mineral Assemblages

Uraninite (Pitchbelnde), Coffinite