UPb, SmNd and KAr systematics of the Akouta uranium deposit, Niger

Abstract

Different minerals of the Akouta sandstone-hosted uranium ore deposit in Niger have been investigated by Ub, SmNd and KAr isotopic systematics. The age of mineralization, derived from U-Pb and K-Ar results, is between ∼ 260 and ∼ 130 Ma, which contrasts with the Viséan age of the host Guézouman Formation (∼335 Ma) and consequently rules out a synsedimentary origin of the U ore. SmNd data on uranium oxide samples are widely scattered and do not provide valuable chronological information. However, Nd isotope data suggest that the regional peralkaline volcanic or plutonic rocks were a probable source of uranium for the Akouta ore deposit.