Nonlinear forcing of climate on mountain denudation during glaciations

Type Article
Date 2021-01
Language English
Author(s) Mariotti ApollineORCID1, Blard Pierre-Henri1, 2, Charreau Julien1, Toucanne SamuelORCID3, Jorry StephanORCID3, Molliex Stéphane1, 4, Bourlès Didier L.5, Aumaître Georges5, Keddadouche Karim5
Affiliation(s) 1 : CNRS, Université de Lorraine, CRPG, Nancy, France
2 : Laboratoire de Glaciologie, DGES-IGEOS, Université Libre de Bruxelles, Bruxelles, Belgium
3 : IFREMER, Laboratoire Géodynamique et Enregistrement Sédimentaire, Plouzané, France
4 : Laboratoire Géosciences Océan, Institut Universitaire Européen de la Mer, Plouzané, France
5 : Aix-Marseille Univ., CNRS, IRD, INRA, Coll. France, UM 34 CEREGE, Technopôle de l’Environnement Arbois-Méditerranée, Aix-en-Provence, France
Source Nature Geoscience (1752-0894) (Springer Science and Business Media LLC), 2021-01 , Vol. 14 , N. 1 , P. 16-22
DOI 10.1038/s41561-020-00672-2
WOS© Times Cited 6
Abstract

Denudation is one of the main processes that shapes landscapes. Because temperature, precipitation and glacial extents are key factors involved in denudation, climatic fluctuations are thought to exert a strong control on this parameter over geological timescales. However, the direct impacts of climatic variations on denudation remain controversial, particularly those involving the Quaternary glacial cycles in mountain environments. Here we measure in situ cosmogenic 10Be concentration in quartz in marine turbidites of two high-resolution cores collected in the Mediterranean Sea, providing a near-continuous (temporal resolution of ~1–2 kyr) reconstruction of denudation in the Southern Alps since 75 kyr ago (ka). This high-resolution palaeo-denudation record can be compared with well-constrained climatic variations over the last glacial cycle. Our results indicate that total denudation rates were approximately two times higher than present during the Last Glacial Maximum (26.5–19 ka), the glacial component of the denudation rates being 1.5+0.9−1.0 mm yr−1. However, during moderately glaciated times (74–29 ka), denudation rates were similar to those today (0.24 ± 0.04 mm yr−1). This suggests a nonlinear forcing of climate on denudation, mainly controlled by the interplay between glacier velocity and basin topography. Hence, the onset of Quaternary glaciations, 2.6 million years ago, did not necessarily induce a synchronous global denudation pulse.

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Mariotti Apolline, Blard Pierre-Henri, Charreau Julien, Toucanne Samuel, Jorry Stephan, Molliex Stéphane, Bourlès Didier L., Aumaître Georges, Keddadouche Karim (2021). Nonlinear forcing of climate on mountain denudation during glaciations. Nature Geoscience, 14(1), 16-22. Publisher's official version : https://doi.org/10.1038/s41561-020-00672-2 , Open Access version : https://archimer.ifremer.fr/doc/00667/77892/