Petrographic Analysis of Lepidolite-Pegmatites in Lema, Kwara State, North-central Nigeria: Implications for Lithium Mineralisation

Abstract

This study investigates the mineralogical composition and potential for lithium mineralisation in lepidolite-pegmatite samples from the Lema Pegmatite Field in north-central Nigeria. Petrographic analysis was conducted on three representative samples (L1, L2, and L3) using thin-section microscopy under plane polarized light (PPL) and crossed polarized light (XPL). The results reveal that muscovite is the predominant mineral, constituting 45%, 50% and 55% of L1, L2 and L3 respectively, while Quartz is notably abundant, making up 20% in L1, 25% in L2 and 20% in L3. Plagioclase and Biotite are also present in significant amounts, indicating a complex mineral assemblage where muscovite could be co-existing with lepidolite of enhanced lithium content. The findings suggest that, while lepidolite is a significant lithium-bearing mineral, it may not be the dominant component in these samples, with Muscovite emerging as a major constituent. This diverse mineralogy highlights the geological complexity of the pegmatites and underscores the need for further exploration and characterisation to assess the economic potential of these rocks in supporting the ongoing energy transition. Future research should focus on quantitative assessments of lepidolite and its lithium content, alongside geochemical methods, to evaluate the viability of these deposits in the context of global lithium demand.