The West African craton and its geophysical signatures

This study examines existing and newly compiled geophysical representations of the West African Craton (WAC) in terms of its large-scale tectonic architecture. In order to build an interpretation with a significant depth extent we draw upon a range of geophysical data, principally seismic tomographic inversions, receiver functions, gravity and magnetics. We present these results as a series of layers providing a series of depth slices though the lithosphere. The different geophysical methods suggest partitioning of the WAC into three tectonic elements at the largest scale which is observed in both seismic tomographic images, Lithosphere Asthenosphere Boundary models and long wavelength gravity signals. The different models of the Moho based on these gravity or seismic datasets show little or no correlation between the models, either for short or long-wavelength features, and show little correlation with receiver function inferred crustal thickness estimates. Manual interpretation of low wavelength gravity and magnetic data suggest a continuation of the WAC across the western margin of the modern boundary, and also highlight distinct domains interpreted to be of Birimian age.