Geochemical and gamma spectrometric analysis of ores ad hostrocks of the Kanawa uranium occurrence in NE Nigeria

The Kanawa mineralization is one of the numerous low grade U-occurrences in the Gubrunde horst, NE Nigeria. Eighty nine samples consisting of ore and host rocks have been analyzed for 12 elements and 3 isotopes by atomic absorption spectrometry, colorimetry and direct γ-spectrometric methods and the data described using multivariate statistical techniques. The results show an enhancement of U, Mn, P2O5, Fe2O3, CaO, 210Pb, 226Ra and 234Th in the ore zones. The element/isotopic associations (U-P2O5-210Pb-226Ra-234Th),(Na2O-K2O-MgO),(Fe2O3-MnO-CaO-Cu) were established in the mineralized rhyolites, while (P2O5-210Pb-226Ra-234Th), (Na2O-K2O-MgO-Zn) and (Fe2O3-Mn-U) occur in the altered/unmineralized rocks. The variation in the pattern of association of Cu, U, Zn and CaO could be ascribed to their remobilization, depletion, enrichment or introduction in the ore zone by hydrothermal solutions. The elements/isotopes U, Zn, Cu, P2O5, 226Ra, 210Pb, 234Th or their ratios could in addition to Pb, Ba, Ce, Sm be used as pathfinder elements in prospecting concealed ores in NE Nigeria. (author) 15 refs.; 4 figs.; 4 tabs