Assessment of the subsurface architecture insights across the Pan African Belt in Northern Cameroon: Applications of 2.75D Geophysical Modelling of Aeromagnetic Data from the Guider-Kaele Area.

Abstract

In this study, aeromagnetic data were used to construct a geological model of the Guider-Kaele area in northwestern Cameroon, which is part of the northern segment of the Pan-African belt in Cameroon. The area is dominated by the Poli and Mangbei lithostratigraphic Groups (Neoproterozoic metasedimentary rocks and metavolcanic rocks) intruded by late Pan-African granitoids and tertiary ring complexes. For quantitative analysis, 2.75D forward modelling of these magnetic data was performed using Oasis Montaj v. 8.4 along four transects oriented N‒S (two lines), NNE‒SSW and NNW‒SSE.. Well log information, borehole data, geologic maps, previous geophysical studies, and Euler deconvolution depth estimates constrained the models derived. In particular, Euler’s deconvolution estimated the depth to the magnetic sources (faults and some intrusions) in the 0.39 km to 11.44 km range beneath sea level. Furthermore, the proposed geological models highlight a subsurface composed of a volcanic-sedimentary cover overlying a granitic faulted basement, with some igneous intrusions (doleritic dyke swarms and granodiorites) and several troughs filled with volcanic-sedimentary deposits. In addition, these models reveal that the crust is thinning. The presence of a prominent greenschist layer in this area testifies to the thermal history or degree of metamorphism of its bedrock.