REE Geochemistry of Uranium-Bearing Columbite-Tantalites and Multiple Oxide Phases from Proterozoic Rare Metal Pegmatites of Pandikimal and Adjoining Areas, Jharsuguda District, Orissa

Rare earth element (REE) geochemistry of uranium bearing columbite-tantalite and multiple Nb-Ta oxide phases from the Pandikimal-Jangapara pegmatites, Jharsuguda district, Orissa have been studied and evaluated columbite-tantalite from these areas contain low ∑REE (100-1000 ppm) with LREE/HREE_CN<0.5 and minor amounts of uranium (0.3-0.6 % U₃O₈). Multiple oxide phases (yttrotantalite, samarskite, microlite and fergusonite) contain elevated amounts of U (10-11 % U₃O₈) and REE (19-28 %) with HREE>LREE. Plot of ∑REE vs. Chondrite-Normalised LREE/HREE shows positive correlation in 'U' rich multiple oxides compared to those from columbite tantalites which tend to show a negative correlation. The LREE/HREE ratio is 0.24 with negative Eu anomaly (Eu/Eu = 0.1) indicating evolved nature of these pegmatites.