Water-level changes in the Flevo area, central Netherlands (5300-1500 BC): implications for relative mean sea-level rise in the Western Netherlands

The younger (post 4000 cal BC) part of the water-level curve for the eastern Flevo area, central Netherlands runs below the relative mean sea-level (MSL) curve for the western and northern Netherlands (Mededelingen Rijks Geologische Dienst 36(1) (1982) 93pp). We investigated if this difference can be attributed to (i) root rejuvenation of the bulk-dated basal peat samples on which the curve for the eastern Flevo area is based and/or (ii) underestimation of the water depth in which the dated peat accumulated. It appears that these potential sources of error did not influence significantly the results obtained by Roeleveld and Gotjé (De Holocene laagveenontwikkeling in de randzone van de Nederlandse kustvlakte (Noordoostpolder), unpublished Ph.D. Thesis, Vrije Universiteit Amsterdam, 1993, pp. 76-86). On the basis of new and recently published water-level data from the eastern and southwestern Flevo area we confirm, refine, and tentatively extend the water-level rise reconstruction by Roeleveld and Gotjé and establish a relative MSL-trend curve for the central Netherlands. The systematic age differences of our radiocarbon dates on various fractions of four new basal peat samples from the eastern Flevo area support the interpretation by Roeleveld and Gotjé that the younger part of the 1982-MSL curve may be based on basal peat samples (all from the Rotterdam area), that have been dated 100-200 yr too old. If this interpretation is correct, the fact that the relative MSL curve for the central Netherlands lies below the 1982-MSL curve cannot be interpreted to indicate less crustal subsidence for the Rhine-Meuse delta, as predicted by geophysical modeling (J. Quat. Sci. 17 (2002) 535).