Main structural lineaments of the southern Cameroon volcanic line derived from aeromagnetic data

Abstract

The Cameroon Volcanic Line (CVL) is an African-only active alkaline intraplate feature that ranges in age from Oligocene to recent, with volcanoes crossing the oceanic-continental boundary. Because of its Cenozoic tectonic processes and magmatic features associated to seismic and volcanic activity, studies of the CVL geodynamic are of great importance. Despite its shear zone features, detailed structural geophysical studies of the southern CVL remain elusive. In this work, we use high-resolution airborne magnetic data to reveal geophysical signatures of the CVL. We apply a combination of derivative and phased filters and an improved cross-correlation approach to delineate geological structures of the southern CVL and propose an interpretation from aeromagnetic data. Derivative and phased filters highlight three distinct magnetic domains, with high positive and negative amplitudes. Rata Mount and Rumpi Hills, for example, show a NE-SE trend and a high magnetic amplitude. This finding might be explained by different types of rocks, consisting of the Upper Cretaceous basalt and sandstone sequences. The intensity of the enhanced horizontal gradient amplitude (EHGA) is well associated with geological features and its effects on a topographic relief. From the cross-correlation analysis, we successfully obtained the magnetization direction of a few specific anomalies.