Lateglacial/Holocene environmental changes in the Mediterranean Alps inferred from lacustrine sediments

• Published in: Quaternary Science Reviews
• Main Authors: Brisset, Elodie, Guiter, Frédéric, Miramont, Cécile, Revel, Marie, Anthony, Edward, Delhon, Claire, Arnaud, Fabien, Malet, Emmanuel, De Beaulieu, Jacques-Louis
• Other Authors: Institut méditerranéen de biodiversité et d'écologie marine et continentale (IMBE), Centre National de la Recherche Scientifique (CNRS)-Institut de recherche pour le développement IRD : UMR237-Aix Marseille Université (AMU)-Avignon Université (AU), Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Collège de France (CdF (institution))-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD), Ecosystèmes continentaux et risques environnementaux (ECCOREV), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Géoazur (GEOAZUR 7329), Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement (IRD France-Sud )-Centre National de la Recherche Scientifique (CNRS)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA), Institut Universitaire de France (IUF), Ministère de l'Education nationale, de l’Enseignement supérieur et de la Recherche (M.E.N.E.S.R.), Culture et Environnements, Préhistoire, Antiquité, Moyen-Age (CEPAM), Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)-Université Nice Sophia Antipolis (. - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA), Gestion des ressources naturelles , environnements et sociétés (GReNES), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)-Université Nice Sophia Antipolis (. - 2019) (UNS), Environnements, Dynamiques et Territoires de la Montagne (EDYTEM), Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry )-Centre National de la Recherche Scientifique (CNRS), Institut Méditerranéen d'Ecologie et de Paléoécologie (IMEP), Université Paul Cézanne - Aix-Marseille 3-Centre National de la Recherche Scientifique (CNRS)-Avignon Université (AU)-Université de Provence - Aix-Marseille 1
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2015
• Subjects: Lake sediment; Holocene climatic optimum; pollen stratigraphy; cirque glacier; Lateglacial; Mediterranean Alps; 14C ages; [SDE.MCG]Environmental Sciences/Global Changes; [SDU.STU.ST]Sciences of the Universe [physics]/Earth Sciences/Stratigraphy; [SDU.STU.GM]Sciences of the Universe [physics]/Earth Sciences/Geomorphology; [SDU.STU.GL]Sciences of the Universe [physics]/Earth Sciences/Glaciology; [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces; environment; Greenland; glacier
• Online Access: https://hal.archives-ouvertes.fr/hal-02046338; https://hal.archives-ouvertes.fr/hal-02046338/document; https://hal.archives-ouvertes.fr/hal-02046338/file/Brisset%20et%20al.%202015_QSR.pdf; https://doi.org/10.1016/j.quascirev.2014.12.004

International audience This study investigates sediment cores from the Mediterranean alpine lakes located in upvalley cirques upper than 1700 metres a.s.l. using sedimentological, palynological and geomorphological studies, in order to document environmental changes following the last phase of glacier retreat. These results are considered in the framework of the deglaciation characterized from 16 sediment cores from high-altitude lakes and mires including 104 14C ages and geomorphological studies of the Mediterranean Alps. Considering each sediment core proxy as an independent observation, i.e., comparisons between 14C ages and palynostratigraphy, between 14C ages and lithostratigraphy, between palynostratigraphy and lithostratigraphy, these data are aimed at contributing to a better understanding of the timing of postglacial environmental changes. The 14C ages combined with pollen biostratigraphy indicate that the deglaciation of cirque catchments is dated between 14,500 and 13,000 cal. BP, i.e., during the Lateglacial Interstadial (Greenland Interstadial-1e). The sixteen lacustrine and mire sediment records are systematically characterized by three units from bottom to top: organic-poor blue clay, beige to light-brown silty clay and organic rich dark brown gyttja lithotype. During the Younger Dryas, lakes located below 2300 m a.s.l. were ice-free and their pollen record indicates steppe conditions. The sedimentary facies also informs on the timing of glacial-dominated processes. The onset of organic-rich gyttja is dated at 11,000 cal. BP suggesting the last influence of cirque glaciers in these lakes at the beginning of the Holocene. The timing of the onset of this organic rich unit differs in sites (±2000 years) probably due to an altitudinal and exposure gradient of the glacial cirques. The presence of gyttja from 11,000 cal. BP to Present indicates biogenic infilling lake for all the Holocene. Even though the literature have indicated rock glacier advances occurred during the Holocene (Subboreal and LIA) ...