VERTICAL VARIATIONS IN ELEMENTAL MATRICES OF SOME RARE EARTH ELEMENTS (REEs) IN PRECAMBRIAN PEGMATITE OF KEFFI, NORTH CENTRAL NIGERIA USING RELATIVE STANDARDIZATION METHOD OF NEUTRON ACTIVATION

The Keffi areas host abundant pegmatite bodies as a result of the surrounding granitic intrusions. In this study, relative standardization method of instrumental neutron activation analysis (INAA) has been used to investigate the vertical deviations of the elemental matrices of REEs namely: total contents of rare earth elements (∑REE); ratio of light to heavy rare earth elements (LREE/HREE), which defines the enrichment or depletion of REEs; europium anomaly (Eu/Sm); La/Lu ratio relative to chondritic meteorites. The study showed no significant variations in the total content of rare elements between the vertical depth profiles (100-250 m). However, higher total concentrations of REE (~ 92.65 ppm) were recorded at the upper depth of the pegmatite. The europium anomaly was consistently negative at all the depth profile. In addition, analyses have shown that heavy REEs are depleted at all depth profiles of the Precambrian Pegmatite of Keffi.