On the use of global potential field models for regional interpretation of the West and Central African Rift System

Abstract

The use in regional interpretations of the Earth Gravity Model (EGM08) and Earth magnetic model (EMAG2) is evaluated by comparison to ground gravity and aeromagnetic data in the central sector of the West and Central African Rift System (WCARS). The comparison includes upward continuation, spectral analysis and pseudogravity calculation and statistical evaluation. A correlation between EMAG2 (which contains roughly 25 km resolution aeromagnetic data in the region) and near-surface aeromagnetic data over WCARS is only true for the very low wavelength part but a strong similarity between EGM08 and ground gravity data can be confirmed. Interpretation of the EGM08 data allows identifying and confirming the position of major structural trends, and provides new information on the crustal architecture. The lineaments limiting different grabens forming the Logone Birni basin and in the southern Chad basin are identified. The results presented here show the use of EGM08 data for regional interpretations over Cameroon and adjacent countries, which can overcome the absence and sparseness of data in developing countries and remote areas.