Uranium isotopic disequilibrium in ground water as an indicator of anomalies

Abstract Because of the unique elemental and isotopic properties of uranium, ground water surveys are a most appropriate approach to prospecting for surficial and secondary uranium deposits. Uranium (4+) is generally immobile, but in oxidising and carbonate bearing waters U (6+) is mobile and conservative. Uranium-234 is the radiogenic daughter of 238 U. The intervening α-decay event causes recoil displacements and radioactive disequilibrium between the two isotopes in open systems such as surficial aquifers. Extreme variations in dissolved uranium composition of ground waters combined with significant variations in the ratio 234 U/ 238 U are indicative of the proximity and stage of evolution of secondary deposits.