Holocene relative mean sea-level changes in the Wadden Sea area, northern Netherlands

Although the Netherlands has a long tradition of sea-level research, no Holocene relative sea-level curve is available for the north of the country. Previous studies hypothesized that the relative sea-level reconstruction for the western Netherlands is also valid for the northern part of the country. However, glacial isostatic adjustment (GIA) models predict a lower and steeper relative sea-level curve because of greater postglacial isostatic subsidence. Long-term data of relative sea-level change are important to inform GIA models and understand postglacial vertical land motion related to the rebound of Fennoscandia and neotectonic activity. We compiled and evaluated a set of basal peat radiocarbon dates to reconstruct the Holocene relative mean sea-level rise in the Dutch Wadden Sea area. For the early Holocene, this reconstruction is lower than the western Netherlands curve. After 6400 cal a BP, the curve for the Wadden Sea is statistically indistinguishable from that for the western Netherlands, a result that conflicts with GIA model results. It remains to be investigated whether the problem lies with the GIA model predictions or with the quality of the available data. Additional basal peat radiocarbon dates from suitable sites should be collected to further resolve this problem.