Browsing by Author "Jimoh, Ayoola Yusuf"

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    Biostratigraphy and Palaeoecological Studies of the Late Cretaceous-Tertiary Sediments in the Dahomey Basin, Nigeria
    (European Journal of Environment and Earth Sciences, 2022-07-25) Saadu, Bolaji Mariam; Jimoh, Ayoola Yusuf; Adekeye, Adeleye Olabisi; Issa, Ayinde Taofeeq
    The Maastrichtian–Eocene sediments (mainly shales and limestones) penetrated by the Itori borehole and Ilaro boreholes in the Dahomey Basin were investigated for foraminiferal biostratigraphy and palaeoecological interpretation. These boreholes penetrated Araromi, Ewekoro, and Oshosun formations at varying depths. Selected shale sediments were subjected to foraminiferal analysis and many planktonic and benthic species of foraminifera (agglutinated and calcareous) were recovered from the Cretaceous interval of the penetrated boreholes. Twelve species of planktic foraminifera (Globalomalina planocompressa, G. pseudomenardii, Globigerina inaequispira, Acarinina cf.coalingenis, Acarinina nitida, Chiloguembelina cretacea, chiloguembelina subtriangularis, Orthokasrstenia sp., Hedbergella holmdelensis, Globigerina sp., Globigerinelloids asperus, Morozovella formosa formosa) and thirteen species of benthic i.e Bolivina sp., B. Crassicostata, , E. africana, Eponides psuedoelevatus, Gavelinella cf. guineana, Gavelinella pachysuturalis, Haplophragmiodes sp., Lenticulina cyprina, L. inornata, L. olokuni, L. psuedomamilligera, L. taylorensis, Nonionella communis, N. spissa, N. panamensis, Orthokarstenia sp., Planulina oyae) were identified. In general, benthic species of infauna deposit feeder and epifauna dominate the population. These species occupy a range of environments from dyoxic to anoxic, brackish water to marsh environment down to upper bathyal depth. Based on the abundant and stratigraphical distribution of the foraminiferal species, four biostratigraphic zones were recognized: Afrobolivina afra zone of late Maastrichtian, Globigerina zone of early Paleocene, Globalomalina pseudomenardii zone of late Paleocene and Morozovella formosa formosa zone of the early Eocene.
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    (Ilorin Journal of Science, 2024) Bolaji, M; Adekeye, Olabisi Adeleye; Jimoh, Ayoola Yusuf; Nasiru, A
    The shales from the Araromi Formation penetrated by the Erekiti borehole in the Dahomey basin were analyzed for their source area and paleo weathering conditions. Ten (10) samples were subjected to X-ray fluorescence (XRF) and X-ray diffraction (XRD) analyses. The major oxide revealed an abundance of SiO2 and Al2O3 (average 32.81 wt.% and 13.11 wt.% respectively) and depletion of TiO2, Fe2O3, CaO, MgO, and MnO, while the trace elements present includes an abundance of V, Cr, Zr, Sr, Zn, Ba and depletion of Sc, Co, Ni, Cu, As, Rb, Sr, Y, Nb, Mo, Pb, Th, and U. The results shows that the shales are associated to intermediate to felsic igneous origin under a very low weathering intensity. The mineralogical composition reveals quartz, gypsum, and calcite as the most abundant and the presence of other accessory minerals such as Kaolinite, K-feldspar, and plagioclase. The high percentage of quartz and gypsum confirmed the low weathering condition.
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    Geochemistry and Mineralogy of Maastrichtian Coals from the Anambra and Gongola Basins of Nigeria: Implications for Coal Quality, Resource Potential, and Agglomeration Characteristics
    (2024-06-22) Jimoh, Ayoola Yusuf; Bolaji, Mariam; Ajadi, Jimoh; Aminu, Shakirat Mustapha; Akinpelu Adelodun Mutiu
    Anambra and Gongola basins are part of the sedimentary inland basins in Nigeria characterized by fossil fuels and in response to its present energy problem, Nigeria has shifted its power generating focus to coal. The studied coals were obtained from two localities, namely Ankpa and Maiganga in Kogi and Gombe States, respectively. The coals were investigated to determine its quality in terms of use and resource potential. The coals were analyzed by proximate, ultimate, elemental, mineralogy and scanning electron microscopy-energy dispersive spectrometry analyses. The objectives of the study are to determine the coals cokability, rank, paleoenvironments, hydrocarbon potential, and slagging tendency. The average values of moisture content, ash, volatile matter, and fixed carbon are 5.54%, 16.42%, 48.45%, and 30.71%, respectively, for Ankpa coals, while Maiganga recorded 10.68%, 8.60%, 44.33%, and 36.41%, indicating high volatile sub-bituminous non-coking coals that are optimum for combustion and electric power generation. The Van Krevelen plot based on the H/C vs. O/C showed Type IV kerogen. The XRD results, correlation plots, and Detrital Authigenic Index (DAI) values of 7.49 and 13.49 in Ankpa and Maiganga coals, respectively, indicated that Ankpa coals are enriched in authigenic minerals like quartz, pyrite, and calcite, while kaolinite and quartz were probable detrital minerals in the Maiganga coals. The agglomeration of the coals deduced by Base/Acid (B/A), Silicon ratio (G), Silica/Alumina (S/A), Iron/Calcium (I/C), Carbon/Hydrogen (C/H), and Fixed Carbon/Volatile matter (FC/V) showed weak–medium-strong for the Ankpa coals and strong for Maiganga coals.
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    Sedimentological and geochemical evaluation of sandstones of the Ilaro formation, Dahomey Basin, Southwestern Nigeria: Insights into paleoenvironments, provenance, and tectonic settings
    (Journal of Nigeria Social and Physical Science, 2024-02-29) Jimoh, Ayoola Yusuf; Saadu, Mariam Bolaji; Adetoro A.A; Ajadi, Jimoh; Issa Ayinde Taofeeq; Issa Umar
    Grain size analysis, geochemistry, and petrography of sandstones of the Ilaro Formation exposed at the Ajegunle area were investigated to infer provenance, transportation history, tectonic setting, paleoenvironment, and degree of palaeoweathering of the sediments. Selected sandstones were analyzed, and the major, trace, and rare earth elements were determined using Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Results from the granulometric analysis showed that sandstones were deposited in fluvial conditions. The sandstones exhibit a coarse-grained texture, displaying poor sorting and being texturally immature. The petrographic analysis indicated that quartz was predominant, whereas opaque minerals, muscovite, and ferruginous ground mass were present in smaller quantities. The sandstones can be geochemically classified as arkose and subarenite. The sandstones have an average composition of SiO2 (82.87%) and Al2O3 (9.49%), while K2O, Na2O, MgO, CaO, and P2O5 have <1% each. The elevated Al2O3 content is associated with the lithic fragment composition, whereas the low concentrations of MgO (mean 0.03%), Na2O (mean 0.008%), and K2O (mean 0.04%) suggest chemical destruction in an oxidizing environment. The angularity of the grains indicated a short transportation history very close to the provenance. Bivariate and discriminant plots from major elements and trace elements suggest the sandstones were non-marine and sourced from intermediate rocks. The sandstones were deposited in an oxic-dyoxic condition under a humid climate and passive or active continental margins. The average values of the weathering indices indicate an intense degree of chemical weathering.