Sea level rise and paleotidal levels from sedimentary structures in the coastal barriers in the western Netherlands since 5600 BP

Abstract

A trendcurve for the rise of mean sea level (MSL) since 5600 BP is given based on 14C-dated coastal sequences. Mean High Water level (MHW) is inferred from the deepest occurrence of dry eolian scour and the highest marine burrow-level and small-scale cross-lamination. Estimates of Mean Low Water levels (MLW) are based on the level of thickest shell beds, the range of structureless sand or bubblesand, the range of low-angle bars and the occurrence of cm-thick clay intercalations. Estimates of MHW have an error of a few decimetres. Those of MLW somewhat more. All data are presented in a 14C time-depth graph and also in a historical time-depth graph (calibrated years BC). MSL is drawn halfway MHW and MLW estimates. The MSL trendcurve indicates a rise of ca. 2 m between 4500 cal BC and 3000 cal BC and ca. 3.5 m during the last 5000 historical years. Our data suggest a tidal amplitude of ca.2m between 4500 cal BC and 3000 cal BC and of ca. 1.50m during the last 2000 historical years.