Source-bordering aeolian dune formation along the Scheldt River (southern Netherlands – northern Belgium) was caused by Younger Dryas cooling, high river gradient and southwesterly summer winds

Abstract

The Younger Dryas cold period caused major changes in vegetation and depositional environments. This study focuses on the aeolian river-connected dunes along the former, Weichselian Late Glacial, course of the Scheldt River in the southern Netherlands. Aeolian dunes along the Scheldt have received little attention, as they are partly covered by Holocene peat and marine deposits. The spatial distribution of the dunes is reconstructed by digital elevation model analysis and coring transects. Dunes are present on the high eastern bank of the Scheldt and in the subsurface of the polder area west of the Brabantse Wal escarpment. A reach-specific higher channel gradient probably caused a channel pattern change from meandering to braiding during the Younger Dryas. This enabled deflation from the braid plain and accumulation in source-bordering river dunes east of the incised and terraced, subsurface Late Pleistocene Scheldt valley. The age of the dune formation is established by pollen analysis and radiocarbon dating of underlying and overlying peat beds. The peat layer below the dune at Zomerbaan is attributed to the Allerød and early Younger Dryas periods. Dune formation occurred predominantly during the second part of the Younger Dryas stadial, both on and in front (west) of the Brabantse Wal escarpment. Wind direction was reconstructed by geomorphic analysis and sedimentary structures on lacquer peels. A southwesterly wind direction is demonstrated by the parabolic dune morphology. For the first time, Younger Dryas wind direction is reconstructed based on adhesion ripple cross-laminated sets on lacquer peels. Sand-transporting south-southwesterly winds were dominant during the Younger Dryas, most likely during summer.

Reinterpretation of Fluvial-Aeolian Sediments From Last Glacial Termination Classic Type Localities Using High-Resolution Radiocarbon Data From the Polish Part of the European Sand Belt

“…Younger Dryas (Greenland Stadial GS-1, 12.9-11.7 ka cal b2k) Distinct and rapid climate cooling at the onset of the Younger Dryas is inferred from European Lowlands (Theuerkauf and Joosten 2012;Słowiński et al 2017;Kasse et al 2020). Climate cooling during this time resulted in a change of river characteristics, regrowth of permafrost and rebuilding of vegetation cover (Vandenberghe 2015;Petera-Zganiacz and Dzieduszyńska 2017;Bos et al 2018).…”

The Dunes of Belvedere–San Marco of Aquileia: Integrating High-Resolution Digital Terrain Models and Multispectral Images with Ground-Penetrating Radar Survey to Map the Largest System of Continental Dunes of Northern Italy

“…Considering the volume of sands forming the dune's field, which extends in continuity for over 15 km 2 and forms ridges with a thickness of up to 15 m, an important source of deflation was necessary, with high sediment availability, at a close distance and mainly in the form of loose sand. In continental aeolian systems, these characteristics are usually satisfied by near fluvial or lacustrine environments during low-water stages, e.g., [13,61,71]. Our interpretation is that the dunes were formed by the Bora wind carrying the sands from the braided channel of Isonzo, flowing just east of the area, along an incised fluvial valley.…”

“…In particular, detailed geomorphological reconstructions of riverine dunes exist in the Netherlands, where the use of LiDAR, stratigraphic and pollen investigations allowed researchers to characterize the morphological pattern, the age and the climate existing during the formation of dune systems along braided river channels. Several examples of these landforms have been documented along former channel belts of the Rhine River [75,76] and the Scheldt River [13]. In most of these cases, the aeolian deposits accumulated over abandoned fluvial terraces, a few meters (i.e., 2-20 m) above the river channel active during their formation and from where the sands have been deflated.…”

“…The situation in northern Italy strongly contrasts with Central and Northern Europe, where continental aeolian landforms and deposits are widely diffused, leaving an important overprint on the present landscape. The so-called "Northern European Sand Belt" characterizes large portions between Great Britain and Russia, where Pleistocene aeolian dunes are well documented in the lowlands, as in the Rhine-Meuse Delta [11][12][13]. In Central Europe, abundant aeolian landforms and deposits are found in Hungary, Serbia, the Czech Republic and Romania [14][15][16][17].…”