The crustal structure along the Mbere trough in South Adamawa (Cameroon) from spectral analysis and gravity modelling

Abstract

The Mbere Cretaceous trough is located in the southern part of the Adamawa province. A gravity interpretation based on data obtained from three NW-SE profiles on the residual anomaly map has been carried out using a 2.5D modelling program. Spectral analysis has been used to estimate the depth of geological structures. The results obtained show that the metamorphic formations consist of gneiss and migmatite which are located in the north of the trough at a mean depth of 9 km. The gradient observed on the Bouguer anomaly map along the trough might not only be due to the northern fault but also due to the contact between the gneiss (and migmatite) and granite under the trough. The thickness of sediments along the trough varies between 1500 and 2250 m with a minimum at Yariban and a maximum at Djohong. The trough is bounded on its sides by faults related to the Central African Shear Zone. Basaltic rocks associated with the Cameroon Volcanic Line are present as intruded rocks lying at a minimum depth of 7200 m. Keywords: bouguer anomaly, residual anomaly, fault, trough Global Journal of Pure and Applied Sciences Vol. 12(1) 2006: 111-117