The Quaternary coversands of southwest France

Abstract

International audienceDetailed stratigraphic analysis and numerical dating (OSL, IRSL, ESR, 14C) of Pleistocene coversands in southwest France enable the construction of a renewed chronostratigraphic framework for sand deposition. The chronological data obtained from sandsheet units testify to the development of transgressive dunefields since at least the Middle Pleistocene (MIS 10). Three main phases of accumulation occurred during the Last Glacial. The oldest one (64–42 ka) is associated with wet sandsheet facies, histic horizons and zibar-type dune fields, which reflect deposition in a context strongly influenced by the groundwater table. The Late Pleniglacial (24–14 ka) corresponds to the main phase of coversand extension in a drier context. Silty gley horizons suggest, however, local interruptions of sand drifting during GS 2.1. Lateglacial stabilization of the coversands may not have occurred before GI-1c (Allerød), which was typified by the development of cumulic arenosols. These were covered by parabolic dunes during the Younger Dryas. The variations in extent of the emerged continental shelf during the glacial–interglacial cycles may explain the uneven geographical distribution of sand deposition through time. Because of coastline retreat up to 100 km north of 45°N during the LGM lowstand, the coversands were unable to reach the northern part of the basin. Comparison with other European regions highlights stronger affinities of the French record with Portugal than with the Netherlands and Great Britain, probably because of reduced influence of permafros

The north-eastern aeolian ‘European Sand Belt’ as potential record of environmental changes: A case study from Eastern Latvia and Southern Estonia

“…A similar aeolian deposition at this time has been also observed elsewhere (Bateman et al, 2000;Derese et al, 2009;Kadlec et al, 2015;Kaliń ska-Nartiša and Nartišs, 2016b;Sitzia et al, 2015;Margielewski et al, 2015). Regionally, a cold and dry climate interval has been noted in E and SE Latvia between 14,200 and 13,300 cal.…”

“…The aeolian activity at the Mustjõgi 3 site in southern Estonia at 11.4 ± 0.8 ka corresponds to the Younger Dryas/Holocene boundary (Walker et al, 2009) and has not been found in the Netherlands probably due to rapid stabilisation of the surface of the aeolian landforms by renewed vegetaion growths (Vandenberghe et al, 2013;Sitzia et al, 2015). However, enhanced aeolian activity took place, e.g.…”

“…Recently, studies of the ESB have focused on reinvestigating known sites and establishing a reliable numerical chronological framework (Derese et al, 2009;Sitzia et al, 2015;Vandenberghe et al, 2013;Zieliń ski et al, 2015) on defining sediment-soil sequences as important chronostratigraphic markers (Beerten et al, 2014;Jankowski, 2012;Kaiser et al, 2009;Küster et al, 2014) and on relating aeolian processes to human activity (Tolksdorf and Kaiser, 2012;Tolksdorf et al, 2010Tolksdorf et al, , 2013. Since the alternation of sand units with soil horizons were thought to reflect the rapid climatic and environmental changes during the Weichselian and Holocene (Vandenberghe et al, 2013), identification of sites has been primarily focused in the western (cf.…”

A map of Pleistocene aeolian deposits in Western Europe, with special emphasis on France

“…(), Sitzia () and Sitzia et al . () [for France], and Cremaschi et al . () [for Italy] were also taken into account.…”

L’œuf ou la poule ? Retour sur le projet Magdatis « Le Magdalénien de la façade atlantique face aux changements environnementaux »

“…De forts vents soufflant principalement depuis le nordouest alimentaient ce système (Bertran et al, 2013 ;Sitzia et al, 2015). Cette région a constitué une zone répulsive limitant le territoire occupé par les groupes humains durant tout le Paléolithique supérieur (Bertran et al, 2013).…”