Abstract

Technological advancement has led to an increase in exploration for Rare Earth Elements (REE) to meet the increasing demand. REE mineralization in Nigeria is largely undefined and there is paucity of data on possible REE bearing rocks, their concentration and distribution. This study was carried out to determine REE concentration and distribution in porphyritic granites around Ilaji-Ile, southwestern Nigeria. Samples of porphyritic granites were subjected to mineralogical characterization using petrography and Scanning Electron Microscope (SEM) while geochemical characterization was carried out using Inductively Couple Plasma Mass Spectrometry (ICPMS). Mineralogical characterization revealed major minerals present are feldspars of albite to andesine composition, quartz, biotite while accessory minerals are titanite, zircon and garnet. ICPMS result revealed La, Ce, Pr and Nd ranged 4-284 ppm, 7 – 610 ppm, 1 – 71 ppm and 4 – 255ppm respectively. ∑REE ranged 160 – 422ppm, with enrichment in Low Rare Earth Elements (LREE ) relative to High Rare Earth Elements (HREE) ({La/Yb}N = 9.3712.45), a weak to strong negative Eu anomaly (0.17-0.59) indicative of removal of plagioclase from the melt during fractional crystallisation and or the presence of plagioclase as a major fractionating phase. REE composition in the granitoids may be lower than the required concentration required for REE exploitation.