Geochemical exploration for uranium in playas.

Although playa sediments at spring discharge areas contain as much as 58 ppm U, evaporation and mobilization processes were found to limit their potential as resources of U. Other metals, however, such as Zn, W, and Au may have a geochemical signature in the playas. There are certain conditions that would make some playas more favorable for the accumulation of U: 1) the presence of precursor carbonate-rich saline lakes; 2) nearby U-rich source rocks; 3) restricted groundwater discharge into the playa; 4) localized precipitation mechanisms or phases in the playa;5) large drainage basins and adequate precipitation; and 6) stability of a hydrologically closed basin for a long period of time.- from Authors