Nonlinear forcing of climate on mountain denudation during glaciations - Archive ouverte HAL Access content directly
Journal Articles Nature Geoscience Year : 2021

Nonlinear forcing of climate on mountain denudation during glaciations

(1) , (1, 2) , (1) , (3) , (3) , (1, 4) , (5) , (5) , (5)
1
2
3
4
5

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.
Fichier principal
Vignette du fichier
Mariotti_NatGeo_Sept 2020.pdf (5.5 Mo) Télécharger le fichier
Origin : Files produced by the author(s)

Dates and versions

hal-03103081 , version 1 (08-01-2021)

Identifiers

Cite

Apolline Mariotti, Pierre‐henri Blard, Julien Charreau, Samuel Toucanne, Stephan J Jorry, et al.. Nonlinear forcing of climate on mountain denudation during glaciations. Nature Geoscience, 2021, 14 (1), pp.16-22. ⟨10.1038/s41561-020-00672-2⟩. ⟨hal-03103081⟩
165 View
42 Download

Altmetric

Share

Gmail Facebook Twitter LinkedIn More