Major And Trace Element Geochemistry Of Pegmatites In Umai, Oban Massif, Se, Nigeria: Constraints On Their Characterization And Mineralization Potential

Abstract

Pegmatites are highly sort for due to their ability to host diverse minerals such as lithium, tantalum, niobium, and gemstones. This study focuses on the geochemistry of the pegmatites in Umai, Oban Massif, SE, Nigeria. The aim is to characterize the pegmatites and infer their mineralization potential. Fifteen (15) fresh samplesere analyzed using inductively coupled plasma mass spectrometry (ICP-MS). Fractional indices such as Ba/Rb, K/Rb, Na/K, K/Cs, Nb/Ta, Ta/Cs, and discrimination plots such as Na₂O+ K₂O vs SiO_2, Rb vs Sr, K/Rb vs Rb, K/Rb vs Cs, Be vs K/Nb, Ta vs K/Cs were utilized in this study. From the geochemical classification diagram of Na₂O+ K₂O vs SiO_2, the pegmatites in Umai are mainly granodioritic in composition. The K/Rb ratio for the samples analyzed are below 100 indicating mineralization. The Nb/Ta ratio for the samples is <1 indicating tantalite mineralization. Also, from the Ta Vs K/Cs plot some data plot on the tantalum mineralization field indicating tantalum mineralization. For some of the samples with Nb/Ta >1, they indicate columbite mineralization. Beryllium concentration >20ppm was observed in some samples analyzed suggesting possible beryllium mineralization.