Application of airborne magnetic data to mineral exploration in the Okene Iron Ore Province of Nigeria
Keywords:
Mineral exploration, Iron ore, Subsurface, Filters, Spectral analysis, Faults and Deposit.Abstract
This work involves the application of airborne magnetic method to exploration of Ajabanoko iron ore deposit in
Okene area of southwestern Nigeria for the purpose of evaluating the deposit geological characteristics and
resource potential. Analyses involving the application of Upward / Downward Continuation filters, Second Vertical
Derivative (SVD) filter and Apparent Susceptibility filter were performed to improve the quality of the magnetic data
for better understanding of the subsurface geology of the deposit. From the downward continuation and SVD
analyses, the small size mineralized bodies and shallow features in the study area were mapped. The faults
delineated were grouped into two based on their trend i.e. NE – SW group and NW – SE group. On the upward
continuation filtered map, a west – east linear feature with a trend similar to the principal orientation of the regional
faults in Okene area was delineated. From the range of magnetic susceptibility values including other analyses,
four rock types namely; migmatite gneiss, granite gneiss, brecciate ferruginous quartzite and iron ore
mineralization were identified. Relative high magnetic susceptible zones (0.016 – 0.017) were inferred as area that
magnetite type iron ore are concentrated in the deposit. The depths to the magnetic sources in the area were
determined using spectral analysis. These depths ranged from 50 m to 300 m.
