Fluid inclusions related to uranium deposits: a review

Fluid inclusions have been observed and studied in rocks of most types of uranium deposits, except surficial ones such as calcretes and the roll-type in sandstone. Temperatures of formation range up to nearly 400°C but most deposits were formed at more moderate temperatures of 90-250°C. It is evident from the relatively small number of studies, however, that the ore-forming process occurred at deeper levels than previously thought.
The chemistry of the fluids ranges from nearly pure water to very dense brines and CO₂ is a common component. In some cases gas analyses allow determination of f_o2 of the fluid, a key parameter for uranium transport and deposition.