Chronostratigraphy of two late Pleistocene loess-palaeosol sequences in the Rhône Valley (southeast France)

• Published in: Quaternary Science Reviews
• Main Authors: Bosq, Mathieu, Kreutzer, Sebastian, Bertran, Pascal, Degeai, Jean-Philippe, Dugas, Pauline, Kadereit, Annette, Lanos, Philippe, Moine, Olivier, Pfaffner, Nora, Queffelec, Alain, Sauer, Daniela
• Other Authors: De la Préhistoire à l'Actuel : Culture, Environnement et Anthropologie (PACEA), Université de Bordeaux (UB)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherches sur les Archéomatériaux (IRAMAT), Université de Technologie de Belfort-Montbeliard (UTBM)-Université d'Orléans (UO)-Université Bordeaux Montaigne-Centre National de la Recherche Scientifique (CNRS), Institut national de recherches archéologiques préventives (Inrap), Archéologie des Sociétés Méditerranéennes (ASM), Université Paul-Valéry - Montpellier 3 (UPVM)-Centre National de la Recherche Scientifique (CNRS)-Ministère de la Culture (MC), DEPARTMENT OF GEOGRAPHY UNIVERSITY OF HEIDELBERG DEU, Partenaires IRSTEA, Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA), Laboratoire de géographie physique : Environnements Quaternaires et Actuels (LGP), Université Paris 1 Panthéon-Sorbonne (UP1)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), Georg-August-University = Georg-August-Universität Göttingen
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2020
• Subjects: loess; southeast France; chronology; geochemistry; grain-size distribution; Last Glacial; [SDU.STU]Sciences of the Universe [physics]/Earth Sciences; Greenland; glacier; Ice Sheet
• Online Access: https://hal.archives-ouvertes.fr/hal-03498579; https://hal.archives-ouvertes.fr/hal-03498579/document; https://hal.archives-ouvertes.fr/hal-03498579/file/2020%20QSR%20Bosq_Chronology%20loess%20Rhone_soumis.pdf; https://doi.org/10.1016/j.quascirev.2020.106473

International audience A sedimentological and chronostratigraphical investigation was carried out on two loess sections (Collias and Lautagne), located in the Mediterranean area along the Rhône Valley (southeast France). High-resolution sampling (5 cm to 20 cm) for magnetic susceptibility, grain size distribution (including non-parametric end-member modelling), colour reflectance and geochemistry was performed. The chronology was based on luminescence dating of quartz grains and radiocarbon dating of small gastropod shells, coupled with hierarchical Bayesian modelling. The Collias section (~8 m thick) records the whole last climatic cycle. It comprises a thick red basal pedocomplex S1 developed during the Last Interglacial and the Early Glacial, similar to that observed elsewhere in southern Europe. Loess deposition occurred during the Lower (L1L2) and the Upper Pleniglacial (L1L1). It was interrupted by soil formation during the Middle Pleniglacial, of which a brown Bwk Manuscript File Click here to view linked References horizon has been preserved (L1S1). By contrast, the 4 m thick Lautagne section provides a detailed record of the Upper Pleniglacial. Weakly developed hydromorphic soils are correlated with the Greenland Interstadials GI-4 to GI-2, while the main period of coarse loess sedimentation corresponds to the stadials GS-5 to GS-2. At a regional scale, the time of loess deposition ranges between 37.5 ka and 12 ka, with a peak at ~26-25 ka, overlapping with the maximal advance of the Alpine Ice Sheet (AIS). This strongly suggests that regional glacier dynamics was the main driver of loess sedimentation.