OGHENEFEGA ISAAC

This study examines the geochemical and mineralogical compositions of five meta-sedimentaryrock samples from Ofu-Eba, Southwest Nigeria, focusing on marble, metaconglomerateandquartzite. One sample was taken from the Ugbogbo area (UGB5), two fromthe Ofu-Ebaarea(EBA3 & EBA4), and two from the Ogbe area (OGB1 & OGB2). Marble (OGB1 &OGB2) hadvery high CaO (87-88%), which set it apart from metaconglomerates (EBA3 &EBA4), whichwere enriched in SiO2 (61-73%) and Al2O3 (7-11%), and quartzite (UGB5), which showedhighSiO2 (70%) and K2O, according to geochemical data (Table 2). These results were supportedbymineralogical investigations (Table 1), which showed a carbonate protolith in marble sampleswith calcite (28–37%) predominating and substantial quartz (35–36%) and orthoclase (27–29%). A siliciclastic origin was suggested by the metaconglomerates' high quartz content (36–38%), feldspars (orthoclase 18–22%, anorthite), and mica (biotite, muscovite). The matrix of quartzitewas primarily composed of quartz (63%), which is indicative of a metamorphic rockthat isextremely siliceous. These variances show a distinct compositional divergence betweenthesilicate-rich metaconglomerates, the highly siliceous quartzite, and the carbonate-richmarble, reflecting variations in protolith composition and metamorphic grade. The results showthevarious metamorphic processes that have sculpted these meta-sedimentary rocks, whichadvances our understanding of the geological evolution of the Ofu-Eba region