Crustal modelling across the West and Central African Rift System, based on gravity, magnetic and seismic data

The West and Central African Rift System (WCARS) extends over several geological domains, including shear zones, volcanic regions, and sedimentary basins. It is home to key geological features such as the Cameroon Volcanic Line (CVL) and the Bangui Magnetic Anomaly (BMA). Despite numerous studies, the detailed crustal structure of WCARS has not yet been fully understood. This work presents a comprehensive 3D crustal study that integrates gravity, magnetic, and seismic data, offering insights into the region’s tectonic framework, rift dynamics, and formation of the BMA. The combined analysis of density, susceptibility, and topographic data reveals five distinct tectonic units, providing a refined understanding of the crustal composition and structure. Analysis of cross-sections along key transects over the study area demonstrates the impact of rifting and magmatic activity on crustal thinning and density distribution. The Central African Shear Zone (CASZ) and the Kandi Shear Zone (KSZ) are identified as key reactivated fault zones that have influenced the spatial distribution and evolution of rift systems. The study also highlights the role of magmatism, driven by the upwelling of molten material, in modifying crustal properties, particularly in volcanic regions such as the CVL and the Benue trough. Our findings suggest a common tectonic origin for CVL, Benue trough, and BMA, with felsic and plutonic intrusions contributing to the formation of the BMA. These results enhance our understanding of the tectonic and geodynamic evolution of the WCARS, emphasizing the role of pre-existing structures and magmatism in shaping the region’s rift architecture.