ORIGINAL PAPER The high-resolution Holocene sea-level curve for Northwest Germany: global signals, local effects or data-artefacts? Friederike Bungenstock • Henk J. T. Weerts Received: 8 June 2008 / Accepted: 24 October 2009 / Published online: 18 December 2009 Ó Springer-Verlag 2009 Abstract A few years ago, a new relative sea-level curve for northwest Germany was constructed for the entire German North Sea coast. It is characterised by several suspected sea-level fluctuations. To test this curve for local effects, it was broken down into five relative sea-level curves representative for five coastal sections. The relative sea-level curves were corrected for tidal effects and also, a rough first correction for compaction was applied. The five curves all differ from the original curve and from each other. Most of the suspected sea-level fluctuations in the original curve cannot be supported and are discussed as data-artefacts or local effects. Around AD 800–1000 all curves show stagnation or drop of sea-level. Thus, this signal is discussed as of over-regional stratigraphic mean- ing. This study is a first step (1) to show that several curves are needed to demonstrate the Holocene sea-level history of such a big area as the entire German North Sea coast and (2) to establish reliable relative sea-level curves for the German North Sea coast. Further research is necessary to apply detailed corrections especially with respect to com- paction-prone data and to improve the individual curves. Keywords Relative sea-level curves Á ‘‘Smoothers’’ Á ‘‘Wigglers’’ Á Northwest Germany Á Data-artefacts Á C 14 -dating Á Glacial forebulge Á Tidal effects Introduction For recent climate and sea-level rise discussions it is of major interest to understand the processes of relative sea- level rise and the reasons for short-term and local sea-level changes. Thus, possible oscillations of sea-level rise on a time-scale of one human generation are also in focus. To prove how reliable sea-level index points indicating an oscillation are, several coastal sections have to be studied and compared. Only a signal observable in all sections can be assumed to be of stratigraphic value and not a result of local effects. There is a more than 50-year-long history and ongoing discussion about (1) the shape of Holocene relative sea- level curves, (2) the evaluation of different kinds of sea- level index points, (3) their representativeness and reliability. The character of the debate between the so called ‘‘smoothers’’, researchers arguing for a continuous smooth sea-level rise, and the so called ‘‘wigglers’’, researchers arguing for a rising but oscillating sea-level trend, has changed during the last years. While many researchers believe that there are temporal differences in the rate of sea-level rise (e.g. Behre 2003, 2007; Freund 2003; Edwards 2001) the question is now whether it is possible to resolve them by field data regarding all errors in age and elevation (Gehrels 1999) and furthermore, whether observed sea-level rise fluctuations are due to local effects not having an over-regional stratigraphic meaning or trig- gered by climate changes. For the coasts of NW-Europe several sea-level curves based on different approaches have been published (e.g. Jelgersma 1979; Roep and Beets 1988; Van de Plassche and Roep 1989; Denys and Baeteman 1995; De Groot et al. 1996; Louwye and Declerq 1998; Edwards 2001; Behre 2003, 2007; Van de Plassche et al. 2005; Bungenstock F. Bungenstock (&) Lower Saxong Institute for Historical Coastal Research, Wilhelmshaven, Germany e-mail: bungenstock@nihk.de H. J. T. Weerts Cultural Heritage Agency, Amersfoort, The Netherlands 123 Int J Earth Sci (Geol Rundsch) (2010) 99:1687–1706 DOI 10.1007/s00531-009-0493-6