Neogene cratonic erosion fluxes and landform evolution processes from regional regolith mapping (Burkina Faso, West Africa)

Jean-Louis Grimaud 1 Dominique Chardon 1 Václav Metelka 1 Anicet Beauvais 2 Ousmane Bamba 3
1 GET - Géosciences Environnement Toulouse
2 CEREGE - Centre européen de recherche et d'enseignement des géosciences de l'environnement
3 Université de Ouagadougou
Abstract : 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/km 2 /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.
Keywords : Source to sink Regolith Pediment Landform evolution processes Sediment routing system
Document type :
Journal articles
Complete list of metadatas

Cited literature [1 references]  Display  Hide  Download
https://hal.ird.fr/ird-01419942
Contributor : Anicet Beauvais <>
Submitted on : Tuesday, December 20, 2016 - 2:53:01 PM
Last modification on : Friday, January 10, 2020 - 9:09:56 PM
Long-term archiving on: Monday, March 20, 2017 - 11:51:02 PM

File

GEOMOR-5234R2_HALL.pdf
Files produced by the author(s)

Identifiers

Collections

IRD | CNRS | OMP-GET | OMP | UNIV-AMU | INSU | PSL | CEREGE | OSU-INSTITUT-PYTHEAS | INRA | UNIV-TLSE3

Citation

Jean-Louis Grimaud, Dominique Chardon, Václav Metelka, Anicet Beauvais, Ousmane Bamba. Neogene cratonic erosion fluxes and landform evolution processes from regional regolith mapping (Burkina Faso, West Africa). Geomorphology, Elsevier, 2015, 241, pp.315 - 330. ⟨10.1016/j.geomorph.2015.04.006⟩. ⟨ird-01419942⟩

Export

BibTeX TEI DC DCterms EndNote

Share

Metrics

Record views

465

Files downloads

409

Contact

Informations

CCSD