LAUSR

Abstract The purpose of this study is to analyze the aeromagnetic data of Ikom and its environs in Cross-River State, Nigeria in order to delineate the structural lineaments according to their spatial and directional attributes as well as define the depth to magnetic causative bodies. This was achieved with the aid of an acquired, digitized and processed aeromagnetic intensity contour map covering Ikom and its adjacent areas. The aeromagnetic data was subjected to diverse data enhancement and transformation routines. Regional-residual analysis was implemented on the total magnetic intensity map (contour interval = 20 nT) to generate a residual magnetic intensity contour map. Results show that the area is characterized by a very complex pattern of magnetic intensities of both long and short wave-lengths. Sequel to the regional-residual anomaly separation, azimuth orientation of the lineament structures delimited on the maps portray N S and NE-SW as the principal trends with E-W and NW-SE as the minor trends. Two depth sources were obtained by employing the commonly known Peter's half-slope method. Depth range for the deeper causative sources is 0.83 km–3.5 km with a magnetic intensity range of −30 nT to −220 nT while the superficial sources had a range of 0.2 km–0.75 km and a magnetic intensity that vary from −10 nT to 20 nT. The deeper magnetic sources are attributed to the underlying pre-Cambrian basement complex rocks and intra basement structures such as fractures and faults whereas the superficial sources are due to basement intrusives as well as ore-bearing veins present in the overlying Cretaceous rocks. The shallow basement depth and prevalence of intrusives and linear structures are indications of an area of good mineral prospects but unfavorable for hydrocarbon formation.