Browsing by Author "Omorinoye, Omolayo Ajoke"

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    Petrography, Geochemistry and Petrogenesis of grey Gneisses of part of Oke-Ode Area, South-Western Nigeria
    (2022) Adedoyin, Adeonipekun Dele; Alebiosu, Mercy Titilayo; Bamigboye, Olufemi Sijuade; Olobaniyi S.B.; Omorinoye, Omolayo Ajoke; Iheme, Kenneth Obinna
    Oke-Ode area, northeast of Ilorin, is part of the Precambrian Basement Complex of southwestern Nigeria. There are no published data on the gneisses, which are well exposed, unlike the adjacent terrains. The area was mapped in order to determine the petrographic, geochemical and petrogenetic attributes of the grey gneisses. The acquired sets of field, mineralogical, and geochemical data indicated that the medium-to coarse-grained gneisses are of igneous origin, and have witnessed multiple tectono-thermal readjustments. Occurrence of xenoliths in the rocks points to magmatic origin. The range of anorthite molecular contents of the plagioclase (An26-34) suggests an andesine to oligoclase composition, indicating derivation from granodioritic to tonalitic progenitors. Petrographic studies showed that the rocks witnessed complex interplay between metamorphism, deformation, and migmatization, which culminated in grain-boundary migration under a relatively stable, low-strain, hightemperature conditions involving mechanical rotation, during grain-scale dynamic recrystallization. Geochemically, plots of Ni vs Zr/TiO₂ and K₂O/Al₂O₃ vs Na₂O₃/Al₂O₃ also constrained the the gneisses to the igneous field while the TiO2 - K2O - P₂O₅ ternary plot further indicated a continental tectonic setting prior to the widespread Pan African magmatism. The rocks are essentially peraluminous calc-alkaline rocks, which are moderately saturated with respect to silica. They are products of fractional crystallization of a basaltic magma in a continental setting but later reworked during the Pan African time. The grey gneises have similar geo-chemical characteristics with some gneisses from other parts of the Basement Complex of Nigeria, but at distinct variance with others.
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    Stable Isotopic Signatures (18O and 2H) and Hydrochemistry in Assessing Basement Aquifer Recharge and Driving Forces of Groundwater Quality in Parts of Ilorin, Northcentral Nigeria
    (University of Technology Sarawak, 2025-01-14) Yusuf, Mumeen Adebayo; Abiye, Tamiru Alemayehu; Alao, Joseph Omeiza; Ibrahim, Kehinde Olojoku; Oyeleke, Tolulope Ayobi; Awujo, Emmanuel Daberechukwu; Omotoso, Oladele Ajiboro; Iheme, Kenneth Obinna,; Bakare, Ussein Taiwo; Omorinoye, Omolayo Ajoke
    Groundwater resources in parts of Asa Local Government Area in Kwara State, Nigeria are threatened by increasing pressure due to growing population, and agricultural and industrial activities, which necessitates a comprehensive assessment of the groundwater resources to ensure their sustainability and safety for human consumption. Evaluation of groundwater resources in parts of Asa Local Government Area in Kwara State, Nigeria was undertaken using the integration of stable isotope of δ18O and δ2H and hydrogeochemical tools including Water Quality Indexes, Gibbs diagrams, and Chadha diagram towards deciphering the source of groundwater recharge as well as factors controlling its chemistry in the study area. The collected groundwater samples from shallow wells and deep boreholes were subjected to major ions, trace elements, and isotope analyses. Hydrochemical models revealed Ca-Mg-HCO3, mixed Ca-Na-HCO3, and Na-HCO3 water facies suggesting the early transformation stage of the groundwater. The WQI indexes ratings revealed essentially fair to good to excellent water quality for human consumption. The isotope values in groundwater samples vary between - 4.12±0.1 ‰ and -2.60±0.1 ‰ and between -15.0±0.2 ‰ and -24.0±0.2 ‰ for δ18O and δ2H, respectively, indicating isotopically relatively enriched groundwater. The plot of δ18O and δ2H in groundwater samples along meteoric lines indicate meteoric origin with little effect of evaporation. Residence time evaluation using Ec and δ18O relationship identified recent recharge and recent recharge but polluted groundwater. In addition, the relation between salinity and δ18O revealed water-rock interaction as the main geochemical process controlling groundwater chemistry.