Abstract

The increase in global demand for rare metal Ta-Nb deposits has caused a resurgence of interest in the search for economically viable deposits. Precambrian pegmatites occurring as near vertical dykes have been studied, with the aim of determining their compositional features and possible economic values. Four thin sections were prepared from the pegmatites of the study area for petrographic study. A total of twenty five samples comprising whole rock pegmatites and extracts of mica were analyzed for major and trace elements using inductively coupled plasma-atomic emission spectrometry analytical technique (ICP-AES). Petrographic study shows that quartz, microcline, plagioclase are the main mineral constituents under transmitted light. From the results, the whole rock pegmatite is considerably siliceous, but with noticeable depletion of silica in the mica extract. Average Fe₂O₃, Mgo, Mno, and TiO₂ values are low in all samples (< 2.00%). The samples are fairly enriched in Rb, Sr, Zr, but comparatively, poor in the rare metals Ta, Nb, W, Cs and Sn. Rare metal mineralization enrichment indices mainly, Ta vs Nb, Ta vs K/Cs, plots, show its depletion in rare metal mineralization, suggesting Ago-Iwoye pegmatites to be barren in rare-metal mineralization when compared with other rare-metal pegmatites across the world.

Key words: Muscovite, pegmatite, mineralization, precambrian, amphibolites.