Determination of Magnetic Basement Depth over Parts of Sokoto Basin, within Northern Nigeria, Using Improved Source Parameter Imaging (ISPI) Technique

ABSTRACT

Improved Source parameter imaging (ISPI) analytical technique for depth to magnetic basement determination was used to determine the thickness to sediment and to delineate lithological contacts within the study area. The study is also focused on delineating structural trends which would either foster the concealment of mineral or hydrocarbon within the area. The study area covers the Northeastern part of the Sokoto basin, North Western Nigeria and it is bounded by Latitude 5N-530’N and Longitude 13E-1350’E with an approximate area of about 3400 km². Regional – residual separation was applied on the TMI map with sheet number 10 and thereafter Improved Source parameter imaging (ISPI) technique applied on the residual map using Oasis Montaj Geophysical software. The Sokoto basin, North Western Nigeria, mainly consist of a gentle undulating plain underlain by basement rocks which are interrupted by low mesas and escarpment. Qualitatively, the result of the study shows a horizontal (cylinder source) model and also dominant E-W and minor NE-SW, NW-SE structural trends while the ISPI automated technique revealed two main (Magnetic) anomalous sources designated with the Long spikes (the deep blue colour) and the short spikes (the magenta, yellow, green and orange colours). The magnetic long spikes reveal deeper magnetic bodies while the short spikes are shallow seated magnetic bodies. The long spikes also indicate areas with thicker sedimentary cover while the shorter spikes highlight areas affected with magnetic intrusions. The ISPI technique highlights sedimentary thickness ranging from 54.1 m to 3384.4 m but with an average thickness of about 739 m. The significance of this result indicates that, even if other conditions are met, the possibility of hydrocarbon exploration will be very minimal.