Tectonic uplift and Eastern Africa aridification.
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.
Sepulchre
Pierre
P
Laboratoire des Sciences du Climat et de l'Environnement, Institut Pierre-Simon Laplace, UMR 1572, 91191 Gif sur Yvette Cedex, France. Pierre.sepulchre@cea.fr
Ramstein
Gilles
G
Fluteau
Frédéric
F
Schuster
Mathieu
M
Tiercelin
Jean-Jacques
JJ
Brunet
Michel
M