Last Glacial Maximum active layer thickness in Western Europe, and the issue of 'tundra gleys' in loess sequences

• Published in: Journal of Quaternary Science
• Main Authors: Bertran, Pascal, Stadelmaier, Kim, Ludwig, Patrick
• Other Authors: Institut national de recherches archéologiques préventives (Inrap), De la Préhistoire à l'Actuel : Culture, Environnement et Anthropologie (PACEA), Université de Bordeaux (UB)-Centre National de la Recherche Scientifique (CNRS), Institute of Meteorology and Climate Research, Karlsruhe Institute of Technology (KIT)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2022
• Subjects: active layer thickness; loess-palaeosol sequences; permafrost; regional climate modelling; tundra gley; Western Europe; [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces; environment; Active layer thickness; Tundra
• Online Access: https://hal.science/hal-03691433; https://hal.science/hal-03691433/document; https://hal.science/hal-03691433/file/2022%20JQS%20LGM%20Active%20layer%20thickness_def.pdf; https://doi.org/10.1002/jqs.3434

International audience Late Marine Isotope Stage (MIS) 3 and MIS 2 loess-palaeosol sequences in Western Europe comprise alternating loess layer and 3-to 30-cm-thick bleached soil horizons with Fe-Mn oxide precipitations, which are usually interpreted as waterlogged active layers and referred to as 'tundra gleys'. Active layer thickness data derived from a regional climate model simulation and the fossils (shells, earthworm granules) found in 'tundra gleys' argue against such an assumption. Most of these horizons better correspond to Fe-depleted, slightly humic topsoil horizons or subsurface eluvial horizons and should be referred to as (incipient) Ag or Eg horizons. They formed during climate ameliorations associated with vegetation (cryptogams, herbs) development, possibly limited by long-lasting snow cover. Strong mixing usually occurred in these horizons due to the activity of anecic earthworms and frost activity.