Browsing by Author "Ojo, Olusola Johnson"

Now showing 1 - 5 of 5
  • Item
    Axis Rotation of a Major F1 Fold during a Retrograde F2 Deformation in Southwestern Nigeria
    (2017) Adedoyin, Adeonipekun Dele; Ojo, Olusola Johnson; Alebiosu, Mercy Titilayo; Adekeye, J.I.D.; Bamigboye, O.S
    North east of Ilorin, South-western Nigeria, a NE-SW trending (F₁) fold which was later refolded, was identified in part of the Basement Complex of the country. The area falls within the West African domain of the Pan African (600±150Ma) remobilized metamorphic terrain. Polyphase deformations, which involved at least three tectono-thermal episodes, were also identified. The area falls within the N-S trending Schist Belts where a large-scale sheeted S1 penetrative metamorphic imprint was successively deformed into an overturned antiformal (F₁) fold and, later, to a broad synformal (F2) fold whose axial traces are generally NE-SW and E-W, respectively. The first deformation episode was essentially metamorphic while the subsequent ones were tectonic. Petrological associations indicate that the rocks are mainly gneisses, psamites and psamitic to semi-pelitic schists, cut by Pan African granitoids. These rocks were deformed under high-temperature, low-pressure amphibolite facies conditions, but downgraded from high to medium grade metamorphic interface during a later tectonic event, under a high geothermal gradient within the upper crust. An occurrence of an overturned fold in the northern end of the axial trace of F1 is attributed to irregular strain distribution that culminated in the open F₂ antiform during the third deformation episode. Of interest, within the context of the structural geology of Nigeria, is the E-W trend of the axis of the F2 fold, which is apparently discordant to the observed general N-S structural trends in the Basement Complex of Nigeria. The origin of this latter structure is attributed to localized tangential deformation, culminating in fold axis rotation in the direction of the X axis, and subsequently overturning and tightening of the original F1 fold during the late- to post- tectonic phases of the Pan African tectonism.
  • Item
    Environmental Impact Assessment of Oluyole Industrial Estate Activities on River Ona Water, Ibadan, Nigeria: Implications to Human Health Risk.
    (2024) Omotoso, Oladele Ajiboro; Ojo, Olusola Johnson; Alebiosu, Mercy Titilayo; Uwais, M.A.; Fadayin, F.A; Adesoba, A.S; Ede, O.E; Asalu, D.O.; Abodugbe, O.O.; Ganiyu, T.O; Olelewe, M.C.; Olaosebikan, Q.O.
    Environmental impact assessment of Oluyole Industrial Estate activities on river Ona water at Ibadan and its relation to human health risk have been investigated using carcinogenic and non-carcinogenic health parameters. Flame-photometry-technique was used to analysis some of the toxic metals from the water samples taken from the study area. Results shown that Fe, Mn, Ni, Pb and Cd had concentrations higher than WHO standard and their CF are >1 with very high Deg.C. The adults’ Exping (for Copper, Iron, Manganese, Nickel, Lead and Zinc) computed are >1 while < 1 for all other metals in children except for Co and Cd respectively. The Hazard Quotient calculated for Pb in adults are >1 and the corresponding Hazard Index are generally >1 (that is, of high chronic risk). The HQ of Fe, Mn, Ni and Pb calculated for children are generally >1 in the industrial areas compared to the upstream (except Pb that also has values >1) which are less than 1. The HI are >1 which also depicts high chronic risk. The CDII is >1. CRing values are greater than prescribed limits of 10-4 and 10-6 respectively. As the cause of elemental elevations for Fe, Mn, Ni, Pb and Cd in the water is being controlled mainly by the effluents being discharged by the industries, the rock weathering processes also controlled Cr, Cu, Zn and Cu in the water has illustrated by the value of CF. Hence, the water is both non-carcinogenic and carcinogenic toxic risks to human health.
  • Item
    Geochemical Assessments of Owa-Kajola Marble, Southwestern Nigeria.
    (2020) Adedoyin, Adeonipekun Dele; Ojo, Olusola Johnson; Adekeye, Jacob Ishola Dele; Alebiosu, Mercy Titilayo
    Extensive deposit of dominantly calcitic marble occurs around Owa-Kajola, Sheet 224 (Osi) NW, south-western Nigeria. Geological field mapping on scale 1:10,000 showed that the marble is intercalated with variably migmatized gneisses, pelitic to semi-pelitic schists, amphibolite, and quartzite, all of which are intruded by late- to post- Pan African granite and pegmatites. Geochemical investigations of the marble were done with a view to ascertaining its industrial applications for national development. Results show that the marble, for which there is no published work, is white, with well-interlocked sub-hedral to euhedral crystals, and medium- to coarse-grained. The physical properties also indicate that it can be used in the production of scouring soap, glass, tooth paste, rubber, polished stones, and lime. The relatively low MgO content against CaO, Slica-Alumina Ratio, Silica Modulus, and the Total Alkali content make the deposit adequate for cement production. The combined high CaO and the low P (<0.1%) and S (<0.5%) make the deposit applicable in the steel industry but the low dolomite content may disqualify it for being used as refractory lining in metallurgical engineering. The amounts of the components of marble such as CaO, MgO, SiO2, P2O5, Fe2O3, Na2O and K2O are within the tolerable limits for the production of Portland Cement while the low levels of P(0-0.1), Pb (<5ppm), U (<0.4ppm) and other deleterious elements make such an industrial venture environmentalfriendly.
  • Item
    Preliminary Assessment of the Quality of Asa River Water, North Central Nigeria: Implications for Irrigation.
    (2018) Omotoso, Oladele Ajiboro.; Ojo, Olusola Johnson; Olojoku, Kehinde; Alebiosu, Mercy Titilayo; Yusuf, Mumeen Adebayo; Kobiowu O.O
    The premilinary assessment of quality of Asa river water, North central Nigeria was carried out using ICP-MS, AAS and volumetric analytical methods in order to assess its suitability for irrigation purposes. The relative abundance of cations and anions in the water samples are Ca2+ >Na+>K+>Mg2+ and HCO3- > SO42->Cl- respectively and the dominant water type is Ca-HCO3. Most of the range of values of irrigation parameters computed are within the recommended limits. SAR falls within excellent range of <10; MAR and SSP fall below recommended value of 50; PS falls below the recommended limit of 3 meq/1; KR falls below 1; RSC falls below 2.5meq/1 and CIA gives an indication of ionic base exchange between Ca, Mg, Na and K ions of the water and the rock types respectively. Under specific ion toxicity, Cl-, Na+ and Boron fall below recommended limits of 106ppm, 69ppm and 0.7ppm respectively. However, the range of HCO3- in the water is from 0.59 to 2.69 meq/1 (average=1.37 meq/1). About 50% of the water samples (taken from the southern part of the river) is greater than 1.5 meq/1 above the prescribed limit. Consequently, the range of pH recorded (Range=7.3 to 8.8; average=8.0) cut across slight-moderate-severe according to the degree of restriction on use, making the water unfit for irrigation purposes. This can lead to reduction in the yields of plants/crops. Respective average values of Fe and Mn in the analyzed water (4.8 and 1.6ppm respectively) are above FAO (1985) standard for irrigation water. Gibbs’ diagram and correlation coefficients of the ion suggest the source of ions from chemical weathering of the aluminosilicate minerals (in the rock types and sediments in the study area), precipitation, leaching of secondary salts and anthropogenic influences from the catchment area. Hence, based on the values obtained for HCO3-, pH, Mn and Fe, the water is unfit for irrigation practices.
  • Item
    Preliminary Investigation of Petrographic and Geochemical Characteristics of Crystalline Rocks in Jebba Central Nigeria
    (2019) Omotoso, Oladele Ajiboro; Ojo, Olusola Johnson; Aina, I.O; Udeafor, J.I.; Alebiosu, Mercy Titilayo
    The preliminary investigation of petrographic and geochemical characteristics of crystalline rocks in Jebba, central Nigeria was carried out in order to establish the various rock types in the area. Petrographic studies were carried out using thin sections of the rock samples and geochemical analysis was carried out using X-ray Fluorescence (XRF) and Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Field mapping indicated that the area is underlain by granite (porphyritic granite), granite gneiss, quartzite and schist. The petrographic studies indicated the main mineral assemblages in the crystalline rocks as; quartz, plagioclase, microcline and biotite. Results of geochemical analysis established SiO2 and Al2O3 as dominant major oxides in the investigated rocks ranging from 46.66 to 97.6 wt. % and 0.25 to 17.48 wt. % respectively. Average values of CIA (Chemical Index of Alteration), PIA (Plagioclase Index of Alteration) and CIW (Chemical Index of Weathering) of the rocks are 59.2, 65.0 and 72.8 (granite gneiss); 58.4, 62.9 and 70.6 (granite); 67.7, 79.9 and 83.3 (quartzite); 57.9, 61.4 and 66.4 (schist) respectively. The intensive weathering of the rocks would have contributed to the concentration of metals in the water phase of the study area. Most of the rare earth elements in granite gneiss are highly enriched with respect to abundance in the earth crust having values greater than 1ppm while granite and quartzite are depleted in these elements.