Sr-Nd Isotope Composition of Uraniferous Leucogranites in the Gaudeanmus area, Central Damara Belt, Namibia

The leucogranite-hosted uranium deposit in Namibia is a well-known intrusive uranium deposit in the world. In this paper, a systematic study of Sr-Nd isotopes has been carried out on uranium mineralized leucogranites in the Gaudeanmus area, Namibia. The results show that uranium bearing leucogranites were formed in the post-orogenic extensional environment, the ε Nd(t) values of the rock are from -13.5 to -17.4, with the initial 87 Sr/ 86 Sr ratios of 0.73035 ∼ 0.79345; and the ages of two-stage Nd model are between 2.32 ∼ 2.63 Ga. The Sr-Nd isotopic geochemical results of the pre-Damara basement, Damara sequence and uraniferous leucogranites indicate that the contribution of uranium rich pre-Damara basement to the ore-forming materials is dominant during the main metallogenic epoch of magmatic crystallization differentiation, while the extra uranium mineralization at the later hydrothermal stage may be from the primary uranium minerals such as uranite and coffinite.