The evolution of the sedimentary environment in the lower River Scheldt valley (Belgium) during the last 13,000 a BP

Abstract

The sedimentary evolution of the alluvial plain of the lower River Scheldt between Wetteren and Dendermonde, was studied based on more than 1000 hand borings, radiocarbon, dendrochronological and OSL dating, palynological analysis and archaeological surveys. The results show a laterally migrating river during the Late Glacial, creating large meander loops. During the Late Dryas fluvial processes interacted with aeolian processes, resulting in dune formation. During the early Holocene, fluvial activity diminished resulting in an underfit river in which vertical accretion became the dominant fluvial process. The presence of multiple small channels in some parts of the study area demonstrates that the fluvial system evolved locally to an anabranching river. Meanwhile vertical accretion continued. Short before the Roman period, the River Scheldt returned to a distinct single-channelled meandering pattern. As lateral migration was limited vertical accumulation processes continued to dominate the fluvial environment. This process was halted by the construction of an extensive network of dikes from the medieval period onwards.