EGU25-17366, updated on 15 Mar 2025
https://doi.org/10.5194/egusphere-egu25-17366
EGU General Assembly 2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
Limited effect of Quaternary climatic cycles on tropical denudation from10Be paleo-denudation rates of the Ogowé catchment (Gabon)
Etienne Large, Julien Charreau, and Pierre-Henri Blard
Etienne Large et al.
  • Université de Lorraine, CRPG, Vandoeuvre lès Nancy, France (etienne.large@univ-lorraine.fr)

The impact of Quaternary glaciations on denudation rates has long been debated and the proposition of the instability of climate as a driver of higher denudation rates since the Pliocene has yet to be proven. Most denudation rate reconstructions have focused on areas either tectonically active or glaciated, or both during that period, leading to difficulty in quantifying the impact of climate cyclicity on denudation, as the deciphering of climatic over tectonic control on denudation can be challenging, and glacial erosion appears to be non-linear, and overprints any other forcing. Furthermore, these studies have mainly concentrated on northern hemisphere or high latitude regions. A global increase of denudation implies other regions should be equally impacted but a large gap in data and knowledge exists in low latitude Tropical regions. Therefore, key regions to better understand the impact of climate on denudation should be free of tectonic activity or glacial processes and located under the Tropics.

In this work, we propose to quantify paleo-denudation rates of the Ogowé catchment (Gabon) over Plio-Pleistocene times by measuring 10Be in quartz grains collected from turbidite samples of three cores and one probe collected 30 km to 200 km offshore the mouth of the Ogowé river. To better constrain transport times of these sediments and quantify their ages of burial, we also measure both radiocarbon ages of vegetal debris contained in the turbidites and 26Al/10Be ratios.

Our results show near constant denudation rates over the Pliocene, leading to two possible conclusions. Either the Quaternary climatic cycles did not affect local tropical climate of the Ogowé region, or denudation rates remain unaffected by climatic variability, at the scale of 10 ka to 100 ka.

How to cite: Large, E., Charreau, J., and Blard, P.-H.: Limited effect of Quaternary climatic cycles on tropical denudation from10Be paleo-denudation rates of the Ogowé catchment (Gabon), EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-17366, https://doi.org/10.5194/egusphere-egu25-17366, 2025.