Could the mantle cause subsidence of the Congo Basin?

In this joint project between the Geological Survey of Norway and GeoForschungsZentrum Potsdam we aim to investigate the role of deep mantle processes in the topographic evolution of the Congo intracratonic basin. The formation of intracratonic sedimentar y basins is poorly understood as they cannot be linked to classic basin-forming mechanisms, such as lithosphere extension. We aim to contribute to solving the enigma of the Congo Basin by considering for the first time the information contained in the sei smic tomographic images of the crust and mantle below the basin. Based on such images, we have found that a high-density body may slowly sink into the mantle underneath the Congo Basin, influencing flow of the mantle and therefore surface topography. We w ill investigate this novel hypothesis by combining mantle flow models, which back-reconstruct bodies indentified in seismic tomography images, with models of the lithosphere stress field and models of lithosphere deformation, to obtain a coherent picture of the evolution of topography in the Congo Basin through time. This project will establish research links between the Geological Survey of Norway and GFZ Potsdam. The Norwegian collaborators will benefit from competence in mantle flow modelling, a field not existing in Norway, while the German collaborators will benefit from the Norwegian expertise in lithosphere deformation and stress field modelling. Our results will not only contribute to improved knowledge of the Congo Basin, but also increase our in sight into basin-forming mechanisms for intracratonic basins. This proposal is relevant for the fields of structural geology, geomorphology, geodynamics, potential field geophysics and hydrocarbon exploration, among others.