Spatial and temporal variations in river terrace formation, preservation and morphology in the Lower Meuse Valley, the Netherlands

Abstract

The Lower Meuse Valley crosses the Roer Valley Rift System and provides an outstanding example of well-preserved late glacial and Holocene river terraces. The formation, preservation, and morphology of these terraces vary due to reach-specific conditions, a phenomenon that has been underappreciated in past studies. A detailed palaeogeographic reconstruction of the terrace series over the full length of the Lower Meuse Valley has been performed. This reconstruction provides improved insight into successive morphological responses to combined climatic and tectonic external forcing, as expressed and preserved in different ways along the river. New field data and data obtained from past studies were integrated using a digital mapping method in GIS. Results show that late glacial river terraces with diverse fluvial styles are best preserved in the Lower Meuse Valley downstream sub-reaches (traversing the Venlo Block and Peel Block), while Holocene terrace remnants are well-developed and preserved in the upstream sub-reaches (traversing the Campine Block and Roer Valley Graben). This reach-to-reach spatial variance in river terrace preservation and morphology can be ascribed to tectonically driven variations in river gradient and subsurface lithology, and to river-driven throughput of sediment supply.