The long-term (107 yr) erosion dynamics of cratonic domains is studied in the present thesis based on the spatial analysis of paleolandsurfaces preserved at the scale of West Africa (~ 4 x 106 km2) since Eocene times. One shows that the West African drainage (i.e. Niger and Volta) was established 24 my ago. Since then, river long profiles have slightly evolved while the position of major knickzones was stabilized on lithological contrasts. The deformation of these profiles was used for gauging epirogenic motion. In very stable zone, landscape dissection with higher resolution shows relief increase despite a relative stability of mean denudation rates (2 m/my). This approach was used to detect masked mineralization hosted by the bedrock and/or to identify ore index redistribution by erosion. Erosion budgets were estimated since Eocene peak greenhouse. The spatial distribution of the denudation suggests the influence of flexural and/or mantellic epirogeny. Estimated volumes were constrained using the porosity and density of eroded regolith. A preliminary source-to-sink comparison was undertaken in the case of the Niger system. While a correlation is shown during the Eocene to Late Miocene interval, the volume deposited during the last 11 my exceeds the estimation of denudation. Surprisingly, the long-term denudation regime of West African has been constant (~ 6.5 m/my) for the last 45 my despite climatic variations. This volumetric budget seems to be typical of non-orogenic domains and would imply a ca. 2 Gt/yr global flux for these domains that represent about ~ 70 % of the Earth surface.
