EFFECT OF CONTINUATION AND DERIVATIVE FILTERS ON A HIGH RESOLUTION AEROMAGNETIC DATA COVERING PARTS OF LOWER BENUE TROUGH AND ANAMBRA BASIN.

This research presents the effect of various filters applied on the residual aeromagnetic map covering parts of lower Benue Trough and Anambra basin. The object of this study is to delineate the boundary of causative magnetic sources, delineate possible tectonic features and the structural controls with their corresponding trend pattern and then extrapolate the influence of those structures on the hydrocarbon and mineral potentials of the area. Using polynomial of different degrees, Regional-residual separation was carried out on the Total Magnetic Intensity (TMI) data and thereafter enhancement techniques like Upward continuation (at various kilometers), first vertical derivative (FVD), second vertical derivative (SVD), second vertical derivative (SVD) performed on the Residual data. The enhancement techniques were applied in order to establish the boundary between magnetic low and highs and also to discriminate the residuals (which are associated with the shallow bodies) from the regional which represents the deeply seated basement magnetic structures. Various contour configurations varying from been linear and elliptical to been irregular and circular, were revealed. These contours reveal possible tectonic trends and structures trending in the NE-SW, NW-SE, N-S and E-W directions. The linear and elliptical contours are possible fault zones and dyke like structures, respectively, existing within the study area while the irregular and circular contours are associated with high differentiation of the basement and possible magnetic aureole respectively. The NE-SW and NW-SE tectonic trends highlight possible oceanic fault and charcot fracture zones that transverse from the offshore Niger Delta region while the N-S and E-W trends are Pan African trends. This fault and fracture zones will, perhaps, serve as conduits for hydrocarbon and other mineralized fluids.