Browsing by Author "Adebisi, WA"

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    Geomagnetic Assessment of the Igbeti Marble Deposit (Nigeria)
    (Springer, 2019) Olatunji, S; Adebisi, WA
    The Magnetic Intensity data of aeromagnetic survey, as conducted by Nigerian Geological Survey Agency, were acquired from sheets 200 and 201 for qualitative and quantitative interpretation purposes. The area is bounded by latitudes 8.5°N–9.0°N and longitudes 3.5°E–4.5°E covering an area of about 6150.50 km2. The data were reduced off the regional field to obtain the residual field. Upward continuation and analytical signal were employed for qualitative interpretations. In addition to Euler and Werner Deconvolutions, spectral depth analyses were carried out to estimate the depth to causative geologic structures and basement of the target marble deposit. The residual field contour shows an intensity ranging from −63.05 to 52.65 nT, indicating series of magnetic highs and lows. The obtained positive residual anomalies could stand as responses to the outcrops common in the area, while the negative field could be associated with the presence of granitoids and felsic volcanic rocks or major fault zones. The reached result prove to reveal minimum and maximum depths of 1.07 and 3.79 km, suggesting an expected thickness extent of the deposit. Further Depth estimate around the current mining appears to range from 2.0 to 2.2 km.
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    Werner Deconvolution Technique for the Interpretation of Residual Anomalies of Igbeti Schist Belt; Implication for Marble Exploration
    (Geological Agency, Ministry of Energy and Mineral Resources Indonesia, 2022) Olatunji, S; Adebisi, WA
    Determination of the straight down range of geologic formation between geographic latitude 8.30 0N to 9 0N and longitude 3.30 0E to 4.30 0E of the Igbeti schist belt became a thing of interest due to the on-going exploration in the region. Aeromagnetic field intensity anomaly data of the bound were then acquired, separated off regional field and a corresponding residual map obtained was later used applying Werner deconvolution method filtering tool. Three magnetic profiles were selected and labelled for the interpretation on the residual anomalies. The result shows that the depth to magnetic source has a maximum value of 1,000 m toward the subsurface in all the profiles selected, indicating the shallow nature of the magnetic source in the area. Based on the structural index shown, it further reveals solutions for contact and dyke which indicates that there are boundaries which separate rocks from one another and the presence of dyke formation. The implication of identical signature from all profiles is that the marble deposit is relative uniform extending to a great depth in the area.