Identification of magnetic structures and their tectonic implications in southwestern Cameroon using satellite aeromagnetic data

Abstract

The Southwestern part of Cameroon exhibits a geologically complex framework dominated by Precambrian rocks and associated structures. Satellite aeromagnetic data were processed and interpreted using different filtering techniques, 3D Euler Deconvolution, and spectral analysis. The findings obtained revealed a variety of magnetic anomalies reflecting variations in the different rock types and structural features. The structural interpretation identifies dominant NE–SW and NW–SE lineaments with subordinate WNW–ESE and ENE–WSW trends. These structures are interpreted within a polyphase tectonic framework in which inherited Precambrian basement fabrics were reorganized during Pan-African transcurrent deformation along the Central African Shear Zone, reactivated during Cretaceous extension associated with the opening of the South Atlantic, and subsequently exploited during emplacement of the Cameroon Volcanic Line. The coincidence of magnetic gradients, Euler-solution clusters, basement-depth discontinuities, and volcanic-intrusive anomalies indicates that structural inheritance and fault reactivation played an important role in controlling basement segmentation, basin development, and magma ascent. The estimated Contact/faults depth from Euler solution with structural index (N = 0) reached a depth of about 2.3  km . Depth estimates from spectral analysis indicate shallow and deep magnetic-source ensembles at approximately 3.17 km and 14.68 km, respectively. Source Parameter Imaging depths range was from 0.22 km to 4.0 km, while 3D Euler deconvolution solutions for contacts and faults range from about 0.05 km to 2.57 km. The shallower depths are associated mainly with uplifted volcanic and basement terrains, whereas the greater depths occur within structurally controlled basement depressions. The magnetic structures therefore preserve a cumulative record of Pan-African deformation, Mesozoic reactivation, and Cenozoic magmatic exploitation, providing a coherent tectonic interpretation of the subsurface architecture of southwestern Cameroon.