Field Observations, Petrography, and Microstructures of Granite from Abeokuta Southwestern Nigeria

Abstract in English The granite of Abeokuta is part the Older Granite suite basement complex southwestern Nigeria. Field observation has identified as porphyritic texture, with a preferred alignment megacrysts K-feldspar >5 cm that are mostly euhedral to subhedral shape. predominantly yellowish, but whitish and pinkish colouration also been observed. dark grey porphyritic, mafic rock composition occurs enclaves within granite, phenocrysts having enclosing granite. Also, show zoning defined by concentric arrangement inclusions biotite relative crystal faces. Petrographic study shows following minerals order abundance: K-feldspar, biotite, quartz, plagioclase, microperthitic intergrowth crystals aligned direction. Evidence such shape K-feldspars, phenocrysts, crystallographic arrangements support magmatic/phenocrystic origin rather than originating growing solid state porphyroblasts.