Geology of the Dutch coast : the effect of lithological variation on coastal morphodynamics

This report provides an overview of the build-up of the subsurface along the Dutch shorelines. The overview can be used to identify areas where the morphological evolution is partly controlled by the presence of erosion-resistant deposits. The report shows that the build-up is heterogeneous and contains several erosion-resistant deposits that could influence both the short- and long-term evolution of these coastal zones and especially tidal channels. The nature of these resistant deposits is very variable, reflecting the diverse geological development of The Netherlands over the last 65 million years. In the southwestern part of The Netherlands they are mostly Tertiary deposits and Holocene peat-clay sequences that are relatively resistant to erosion. Also in South- and North-Holland Holocene peat-clay sequences have been preserved, but in the Rhine-Meuse river-mouth area Late Pleistoceneearly Holocene floodplain deposits form additional resistant layers. In northern North-Holland shallow occurrences of clayey Eemian-Weichselian deposits influence coastal evolution. In the northern part of The Netherlands it are mostly Holocene peat-clay sequences, glacial till and over consolidated sand and clay layers that form the resistant deposits. The areas with resistant deposits at relevant depths and position have been outlined in a map.