Assessment of crustal structures by gravity and magnetic methods in the Calabar Flank and adjoining areas of Southeastern Nigeria—a case study

High-resolution potential field data were used to the study of Calabar Flank. The study is aimed at mapping the tectono-sedimentary framework, and determining depth to basement of the area. The smooth magnetic/gravity curves obtained from the 2-D models reflect thick sedimentary series and deeply buried basement rocks with no significant post rift tectonic events. Also, the main basement structures (that is, the horst and graben) and associated normal fault blocks of the Calabar Flank were properly delineated. Thickness of sedimentary series in some locations in the study area was observed to be ~7000 m, and the stacked models showed that the sediment thicknesses dip gently in the southwesterly direction. The models, particularly the joint gravity and magnetic model, validate the extant conceptual geological model for the area.