Publications des scientifiques de l'IRD

Grimaud J.L., Chardon Dominique, Metelka V., Beauvais Anicet, Bamba O. (2015). Neogene cratonic erosion fluxes and landform evolution processes from regional regolith mapping (Burkina Faso, West Africa). Geomorphology, (241), p. 315-330. ISSN 0169-555X.

Titre du document
Neogene cratonic erosion fluxes and landform evolution processes from regional regolith mapping (Burkina Faso, West Africa)
Année de publication
2015
Type de document
Article référencé dans le Web of Science WOS:000357145100022
Auteurs
Grimaud J.L., Chardon Dominique, Metelka V., Beauvais Anicet, Bamba O.
Source
Geomorphology, 2015, (241), p. 315-330 ISSN 0169-555X
The regionally correlated and dated regolith–paleolandform sequence of Sub-Saharan West Africa offers a unique opportunity to constrain continental-scale regolith dynamics as the key part of the sediment routing system. In this study, a regolith mapping protocol is developed and applied at the scale of Southwestern Burkina Faso. Mapping combines field survey and remote sensing data to reconstruct the topography of the last pediplain that formed over West Africa in the Early and Mid-Miocene (24-11 Ma). The nature and preservation pattern of the pediplain are controlled by the spatial variation of bedrock lithology and are partitioned among large drainage basins. Quantification of pediplain dissection and drainage growth allows definition of a cratonic background denudation rate of 2 m/My and a minimum characteristic timescale of 20 Ma for shield resurfacing. These results may be used to simulate minimum export fluxes of drainage basins of constrained size over geological timescales. Background cratonic denudation results in a clastic export flux of ~ 4 t/km2/year, which is limited by low denudation efficiency of slope processes and correlatively high regolith storage capacity of tropical shields. These salient characteristics of shields' surface dynamics would tend to smooth the riverine export fluxes of shields through geological time.
Plan de classement
Géomorphologie [064GEOMOR]
Descripteurs
CRATON ; EROSION ; NEOGENE ; SEDIMENT ; LATERITE ; TELEDETECTION SPATIALE ; CARTOGRAPHIE ; GEOMORPHOLOGIE ; TOPOGRAPHIE ; REGOLITHE
Description Géographique
BURKINA FASO
Localisation
Fonds IRD [F B010064454]
Identifiant IRD
fdi:010064454
Contact