1. Limited influence of climatic gradients on the denudation of a Mediterranean carbonate landscape
- Author
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Didier Bourlès, Karim Keddadouche, Vincent Godard, Magali Rizza, Georges Aumaître, Lucilla Benedetti, Valery Guillou, Franck Thomas, Olivier Bellier, Vincent Ollivier, Fabrice Hollender, Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Collège de France (CdF)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Institut National de la Recherche Agronomique (INRA), Laboratoire méditerranéen de préhistoire Europe-Afrique (LAMPEA), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Ministère de la Culture (MC), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Collège de France (CdF (institution))-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA), ECCOREV Research Federation, INSU-CNRS, Cashima Research Project - CEA Cadarache, Cashima Research Project - ITER Organisation, CEA, Conseil Regional PACA, INSU/CNRS, ANR through the 'Projets thematiques d'excellence' programme for the 'Equipements d'excellence' ASTER-CEREGE action, IRD, French Government 'Investissements d'Avenir' programme of the French National Research Agency (ANR) through the A*MlDEX project [ANR-11-IDEX-0001-02, ANR-11-LABX-0061], and Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
Mediterranean climate ,landscape evolution ,denudation rates ,010504 meteorology & atmospheric sciences ,Weathering ,precipitation ,cosmogenic nuclides ,010502 geochemistry & geophysics ,01 natural sciences ,carbonate ,chemistry.chemical_compound ,[SDU.STU.GM]Sciences of the Universe [physics]/Earth Sciences/Geomorphology ,Precipitation ,Cosmogenic nuclide ,climate ,ComputingMilieux_MISCELLANEOUS ,Holocene ,0105 earth and related environmental sciences ,Earth-Surface Processes ,15. Life on land ,Tectonics ,chemistry ,Denudation ,13. Climate action ,Carbonate ,Physical geography ,Geology - Abstract
International audience; The dynamics of carbonate-dominated landscapes is still debated, and first-order questions pertaining to the respective importance of chemical and mechanical weathering processes or the influence of climatic variability on denudation rates are largely open. To address these issues, we investigate the denudation pattern across a climatic gradient in Provence, SE France. We focused on a series of major carbonate mountain ranges with elevation spanning 200 to 2000 m and associated with >2-fold variations in mean annual temperature and precipitation. We collected 25 samples from 10 different mountain ranges and quantified denudation rates through the measurement of their Cl-36 concentrations in order to explore tectonic and climatic controls on these carbonate landscapes evolution. We observe that most of our samples experience denudation rates in the 30-60 mm/ka range (averaged over 5 to 40 ka), with no evident dependence on variations of mean annual temperature or precipitation. One range (Lure mountain) stands out as a significant outlier, with much higher denudation rates (>100 mm/ka) than adjacent sites (Ventoux mountain) at the same elevation and experiencing similar present-day environmental conditions. We explore in details the climatic, tectonic and geomorphological contexts of these two ranges in order to understand the reasons for this apparent 3-fold difference in denudation rates. A regionally-documented major Holocene hillslope destabilization event appears to be a likely candidate to explain the observed lower Cl-36 concentrations at the top of the Lure mountain. At longer wavelengths, our regional dataset shows no clear control of modem precipitation gradients on denudation rates, consistent with previous observations in landscapes underlain by other lithologies.
- Published
- 2018
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