The Pyrenees: glacial landforms from the Younger Dryas (12.9–11.7 ka)

• Main Authors: Delmas, Magali, Oliva, Marc, Gunnell, Yanni, Reixach, Théo, Fernandes, Marcelo, Fernández-Fernández, José, Calvet, Marc
• Other Authors: Histoire naturelle de l'Homme préhistorique (HNHP), Muséum national d'Histoire naturelle (MNHN)-Université de Perpignan Via Domitia (UPVD)-Centre National de la Recherche Scientifique (CNRS), University of Barcelona, Environnement, Ville, Société (EVS), École normale supérieure de Lyon (ENS de Lyon)-École des Mines de Saint-Étienne (Mines Saint-Étienne MSE), Institut Mines-Télécom Paris (IMT)-Institut Mines-Télécom Paris (IMT)-Université Lumière - Lyon 2 (UL2)-Université Jean Moulin - Lyon 3 (UJML), Université de Lyon-Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Jean Monnet - Saint-Étienne (UJM)-École Nationale des Travaux Publics de l'État (ENTPE)-École nationale supérieure d'architecture de Lyon (ENSAL)-Centre National de la Recherche Scientifique (CNRS), University Institute of Lisbon (ISCTE), Universidad Complutense de Madrid = Complutense University of Madrid Madrid (UCM)
• Format: Book Part
• Language: English
• Published: HAL CCSD 2023
• Subjects: Younger Dryas stadial moraine; Terrestrial cosmogenic nuclide exposure dating; Climatic gradient; Pyrenees; [SDU.STU.GM]Sciences of the Universe [physics]/Earth Sciences/Geomorphology; North Atlantic
• Online Access: https://univ-perp.hal.science/hal-03989979; https://univ-perp.hal.science/hal-03989979/document; https://univ-perp.hal.science/hal-03989979/file/Chapitre%2056%20%20pour%20HAL.pdf; https://doi.org/10.1016/B978-0-323-91899-2.00038-3

International audience As elsewhere around the North Atlantic, and throughout most European mountains, the Younger Dryas (YD: 12.9–11.7 ka) corresponded in the Pyrenees to a short period of cold climate, less intense than at the time of the Oldest Dryas (~18.9–14.6 ka) but notably colder than at the time of the Bølling–Allerød Interstadial (14.6–12.9 ka). The response of Pyrenean glaciers to the YD cold spike has been documented in just ten sites, mostly by 10Be and 36Cl exposure ages obtained from glacially-polished bedrock steps on valley floors, with only a few exposure ages from moraines and rock glaciers. Despite some uncertainty over age precision (mainly ascribable to uncertainty concerning past snow cover), all existing evidence indicates that YD glaciers, where present, prevailed mostly in the central and western Pyrenees and never exceeded lengths of 2–6 km. Ongoing deglaciation favoured paraglacial readjustments on cirque headwalls, promoting the widespread development of rock glaciers and, more locally, debris-covered glaciers.