Tectonic Uplift and Eastern Africa Aridification
Pierre Sepulchre,1,2*
Gilles Ramstein,1
Frédéric Fluteau,3
Mathieu Schuster,4,5
Jean-Jacques Tiercelin,4
Michel Brunet2
The history of Eastern African hominids has been linked to a progressive increase of open grassland during the past 8 million years. This trend was explained by global climatic processes, which do not account for the massive uplift of eastern African topography that occurred during this period. Atmosphere and biosphere simulations quantify the role played by these tectonic events. The reduced topographic barrier before 8 million years ago permitted a zonal circulation with associated moisture transport and strong precipitation. Our results suggest that the uplift itself led to a drastic reorganization of atmospheric circulation, engendering the strong aridification and paleoenvironmental changes suggested by the data.
1 Laboratoire des Sciences du Climat et de l'Environnement, Institut Pierre-Simon Laplace, UMR 1572, 91191 Gif sur Yvette Cedex, France.
2 Laboratoire de Géobiologie, Biochronologie et Paléontologie Humaine, CNRS UMR 6046, Faculté des Sciences, Université de Poitiers, 40 Avenue du Recteur Pineau, 86022 Poitiers Cedex, France.
3 Laboratoire de Paléomagnétisme, Institut de Physique du Globe de Paris, 75252 Paris Cedex 05, France.
4 Institut Universitaire Européen de la Mer, CNRS UMR 6538, Place N. Copernic 29280 Plouzané, France.
5 Bureau des Recherches Géologiques et Minières, Avenue Claude Guillemin, 45060 Orléans, France.
* To whom correspondence should be addressed. E-mail: Pierre.sepulchre{at}cea.fr
