Interpreting gravity anomalies in south cameroon, central africa

Abstract

The area involved in this study is the northern part of the Congo craton, located in south Cameroon, (2.5°N - 4.5°N, 11°E - 13°E). The study involved analysing gravity data to delineate major structures and faults in south Cameroon. The region’s Bouguer gravity is characterised by elongated SW-NE negative gravity anomaly corresponding to a collapsed structure associated with a granitic intrusion beneath the region, limited by fault systems; this was clearly evident on an isostatic residual gravity map. High gravity anomaly within the northern part of the area was interpreted as a result of dense bodies put in place at the root of the crust. Positive anomalies in the northern part of the area were separated from southern negative anomalies by a prominent E-W lineament; this was interpreted on the gravity maps as a suture zone between the south Congo craton and the Pan-African formations. Gravity anomalies’ total horizontal derivatives generally reflect faults or compositional changes which can describe structural trends. The local maxima of the Bouguer gravity data’s horizontal gradient grid and its upward continuation at various altitudes were used to highlight the deepest lineament faults and their dip and direction. These features led to producing a structural map of the study area.