Last Glacial loess in Europe: luminescence database and chronology of deposition

Type Article
Date 2023-05-31
Language English
Author(s) Bosq MathieuORCID1, Kreutzer SebastianORCID2, 3, 4, Bertran Pascal1, 5, Lanos Philippe4, 6, Dufresne PhilippeORCID4, 6, Schmidt ChristophORCID7
Affiliation(s) 1 : PACEA, UMR 5199 CNRS - Université Bordeaux, allée Geoffroy Saint Hilaire, 33615 Pessac, France
2 : Institute of Geography, Ruprecht-Karl University of Heidelberg, Im Neuenheimer Feld 348, 69120 Heidelberg, Germany
3 : Geography & Earth Sciences, Aberystwyth University, Wales, United Kingdom
4 : Archéosciences-Bordeaux, UMR 6034, CNRS - Université Bordeaux Montaigne, Maison de l’Archéologie, 33607 Pessac, France
5 : Inrap, 140 avenue du Maréchal Leclerc, 33130 Bègles, France
6 : Géosciences-Rennes, UMR 6118 CNRS - Université de Rennes 1, 35042 Rennes, France
7 : Institute of Earth Surface Dynamics - University of Lausanne, Géopolis, 1015 Lausanne, Switzerland
Source Earth System Science Data (1866-3516) (Copernicus GmbH), 2023-05-31 , Vol. 15 , N. 10 , P. 4689-4711
DOI 10.5194/essd-15-4689-2023
Abstract

During the last glacial period, the climate shift to cold conditions associated with changes in atmospheric circulation and vegetation cover resulted in the development of large aeolian systems in Europe. On a regional scale, many factors may have influenced dust dynamics, such as the latitudinal difference between the various aeolian systems and the variability of the sources of wind-transported particles. Therefore, the assumption that the timing of aeolian deposition is strictly synchronous in Europe does not seem to be the most plausible hypothesis and needs to be evaluated. To test this assumption, the chronology of loess deposition in different European regions was investigated by studying 93 luminescence-dated loess-palaeosol sequences with their data recalculated and compiled in a single CSV file: the ChronoLoess database. Our study shows that the two major aeolian systems, the Northern European Loess Belt (NELB) on the one hand and the systems associated with the rivers draining the Alpine Ice Sheet on the other hand, developed asynchronously. The significant deposition started at about 32 ka for the NELB vs 40 ka for the perialpine loess and peaked about two millennia later for the former (21.8 ka vs 23.9 ka, respectively). This shift resulted mainly from the time lag between the maxima of the Alpine and Fennoscandian ice sheets, which acted as the primary sources of fine-grained particles through glacial abrasion. The major geomorphic changes that resulted from the development and decay of the Fennoscandian and British-Irish ice sheets also played an important role. Particularly, ice sheet coalescence during the LGM diverted meltwater fluxes through the Manche River and provided vast amounts of glacial particles available for deflation in the western NELB. The period during which the maximum Mass Accumulation Rate was reached for each loess-palaeosol sequence is relatively homogeneous in the NELB and ranges from 30 ka to 19 ka, whereas it is more scattered in the perialpine systems (>60 ka to 14 ka). This probably resulted from a combination of factors, including the asynchrony of maximum valley glacier advances and local geomorphic factors.

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