Browsing by Author "Olasunkanmi, NK"

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    Edge detection and magnetic basement depth of Danko area, northwestern Nigeria, from low‑latitude aeromagnetic anomaly data
    (Springer, 2019) Salawu, NB; Olatunji, S; Adebiyi, LS; Olasunkanmi, NK; Dada, SS
    This study aims at estimating depths and boundaries of magnetic source bodies, in order to provide an indirect insight into subsurface geologic features within Danko area of Kebbi state. The study area is located within low magnetic latitude. Hence, the total magnetic intensity anomaly map was reduced to the magnetic equator. This is to center magnetic anomalies over their respective magnetic source bodies, which equally makes the interpretation of sources easier. Matched filtering of the reduced-to-equator (RTE) magnetic anomaly map indicates that the anomalies could be represented by two equivalent layers with some additional noise. The estimated mean depths of burial for the regional and residual sources are 1000 m and 500 m, respectively. Horizontal gradient magnitude and tilt derivative methods carried out on the RTE aeromagnetic anomaly map facilitated the identification of two distinct geologic trends bounded by a prominent fault suspected to be the documented Yelwa fault. Furthermore, the analytic signal map showed magnetic basement depth values between 50 and 900 m with an average value of 475 m, indicating a compelling alignment of results with the 500 m depth value for the residual matched filter layer. Several mineral occurrences have been found within the outcropping basement rocks of the study area. Hence, the combined appraisal of source edge locations and magnetic basement depth estimates offers useful information of the underlying basement configuration, which is highly essential for mineral exploration targets that are mostly obscured by regolith cover.
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    Integrated geophysical and hydrochemical assessments of Eyenkorin market dumpsite, Asa L. G. A. Kwara state, Nigeria
    (Nigerian Institute of Physics, 2019) Agboola, RO; Sunmonu, LA; Olatunji, S; Olasunkanmi, NK
    Geophysical and Physico-chemical investigations of a waste dumpsite were aimed at assessing the extent of groundwater pollution arising from a leachate plume. Very Low-Frequency Electromagnetic, Resistivity Profiling, and Sounding were employed within the range of 1o100 m in NE:-SW direction, discordant with the orientation of outcrops in the area. VLF-EM results showed high range values (0 -10 µS) of conductivity within a depth range of 5-15 m. Profiling showed a low Resistivity value range (3.79 - 11.0 Ωm) within a depth range of 9 - 12 m. 'The sounding results delineated four - five vertical lithological layers from the geo-electric sections of KIT-type sounding curves. The high conductivity shown by the VLF-EM could be a signature of aquiferous layers in the area. 'The low resistivity value could be evidence of dissolved particles from the decaying rubbish in the waste, forming the constituent of the leachate. The hydro-physicochemical analysis showed concentrations of Magnesium (6.8-8.4) mg/1, Iron (2.0-3.5) mg/l, Manganese (0.5-0.85) mg/1, and lead (0.5 mg/I). Chromium (0.6-0.8) mg/I and Nickel (0.05 mg/I) were present in the water samples, higher than WIIO, 2006, and NSDQW. 2007 standards. Thus, the migration of leachate could have posed a menace of pollution.
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    Interpretation of high resolution aeromagnetic data of Kaoje and its environ, western part of the Zuru Schist belt, Nigeria: implication for Fe–Mn occurrence
    (Helyon, 2020) Olasunkanmi, NK; Bamigboye, O; Olatunji, S; Salawu, NB; Bamidele, T
    This study presents an appraisal of mineralization potential and the geologic record of Kaoje and environs using high-resolution aeromagnetic data. The data were analyzed using the fast Fourier transform technique for reduction-to-equator (RTE), analytic signal (AS), total horizontal derivative (THDR), tilt derivative (TDR), spectral analysis and Euler deconvolution at varying spectral indices. The reduced to equator residual magnetic intensity range from -73.4 to 205.6 nT and are associated with contrasting lithology of the Sedimentary and Basement Complex rocks. The anomalies and analytic signal amplitude unfold and update the extension of Zuru Schist to the southern region of Kaoje, elongated banded gneiss within the schist body, pegmatite intrusion through the migmatite and NNW-SSE trending schist hosted manganite and sandstone-hosted goethite. Estimated depth to shallow and deeper magnetic sources ranged from 0 to 59 m and 225–415 m respectively, and the corresponding Euler solutions revealed perfect clustering along notable geologic features and minerals. The iron mineralization are revealed as sourced from the magmatic bodies that lie beneath the sedimentary rocks and a corresponding sphere geologic model within northwest and southwest of Kaoje at a depth range of 0–225 m. The structural trends suggested the tectonic events in the area and indicate an imprint of Zungeru-Anka transcurrent fault that serves as a conduit for iron mineralizing fluid to Kaoje.