Regard V., Carretier Sébastien, Moquet J. S., Choy S., Blard P. H., Bogning S., Mbonda A. P., Mambela E., Paiz M. C., Séranne M., Charreau J., Rouby D., Bouchez J., Gaillardet J., Braun Jean-Jacques, Denèle Y. (2025). Contrasting physical erosion rates in cratonic catchments : the Ogooue and Mbei rivers, Western Central Africa [+ Corrigendum, 1 p.]. Gondwana Research, 138, 192-209 [+ Corrigendum, 1 p., vol. 140, 2025, p. 158). ISSN 1342-937X.
Titre du document
Contrasting physical erosion rates in cratonic catchments : the Ogooue and Mbei rivers, Western Central Africa [+ Corrigendum, 1 p.]
Année de publication
2025
Auteurs
Regard V., Carretier Sébastien, Moquet J. S., Choy S., Blard P. H., Bogning S., Mbonda A. P., Mambela E., Paiz M. C., Séranne M., Charreau J., Rouby D., Bouchez J., Gaillardet J., Braun Jean-Jacques, Denèle Y.
Source
Gondwana Research, 2025,
138, 192-209 [+ Corrigendum, 1 p., vol. 140, 2025, p. 158). ISSN 1342-937X
We measured the long-term physical denudation of the Ogooue River catchment using Be-10 produced in situ by cosmic rays. These measurements are averaged over 25-200 ka (average 40 ka), depending on the physical denudation rate. The denudation rate of the Ogooue River catchment is slow (38 t/km(2)/a, 15 m/Ma), slightly higher than in Equatorial West Africa (from Senegal to Angola, 26 t/km(2)/a, 10 m/Ma). Physical denudation and chemical weathering fall within the same order of magnitude. Thus, although low, there is substantial chemical weathering compared to physical denudation, that likely contributes over 30 % of the total denudation. Denudation rates are spatially variable (from 10 to 60 t/km(2)/a) within the large Ogooue River catchment. Over the long term, physical denudation and chemical weathering roughly match, except in the Bateke Plateaux area, because the plateaus are made up of already weathered detrital material and therefore their modern flux of solutes is very low (similar to 9.5 t/km(2)/a). The spatial distribution is similar to the one described in the work of Moquet et al. (2021) on the basis of solute fluxes, i.e. the southern part of the catchment is denuding twice as fast as the northern part. We show here that the whole picture did not vary much since 100 ka, as shown by both methods which give consistent results. Faster denudation in the southern part of the catchment may be related to more uplift than in the northern part caused by the southern African "superswell".
Plan de classement
Géologie et formations superficielles [064]
Description Géographique
GABON ; CONGO ; GUINEE EQUATORIALE ; CAMEROUN
Localisation
Fonds IRD [F B010092122]
Identifiant IRD
fdi:010092122
