Walcheren Member

NUNAWA

Formal (Weerts 2003).

Grey fine sand, clayey or silty, calcareous, shelly, bioturbated. Grey clay, silty or sandy, shelly, partly organic, bioturbated. Sand-clay alternations. Local shell lags.

Estuarine or back-barrier tidal basin, established following breaching of a closed barrier coast, including channel (shelly sand), tidal flat and mudflat (sand and mud), and tidal marsh (mud and organics).

Stratigraphically above peat (Hollandveen Member, Nieuwkoop Formation). Unconformable contact with lowest Hollandveen peat, tidal sand and clay (Wormer Member; commonly jointly assigned to Naaldwijk Formation, undifferentiated) or Pleistocene units.

Commonly exposed at the surface. Locally, covered by peaty clay (Echteld Formation).

Up to about 30 m (in the southwest).

Widely distributed in a broad coastal zone within the overall lateral extent of the Naaldwijk Formation, except in the Wadden Sea area (here, not distinguished from Wormer Member).

North Sea: Raan and Hompels Members, Banjaard Formation, and youngest part of the Elbow Formation (mapped in conjunction with the British and Belgian Geological Surveys; Balson et al. 1991; Stoker et al. 2011); UK: British Coastal Deposits Group (McMillan et al. 2011); GER: Dünkirchen Unter-formation (Sindowski, 1968); BEL: Dunkerque Member, Vlaanderen Formation (Paepe & Baeteman 1979).

Holocene (Meghalayan).

Named after the former Island of Walcheren in the southwestern province of Zeeland.

Duinkerke Deposits (Doppert et al. 1975).

Wim Dubelaar (2018), Sytze van Heteren (2019).

Balson, P.S., Laban, C., Schüttenhelm, R., Paepe, R., Baetman, C. 1991. Ostend Sheet 51° N-02° E, Sea bed sediments and Holocene geology. British Geological Survey, Rijks Geologische Dienst, Belgische Geologische Dienst, 1:250000.

Doppert, J.W.Chr., Ruegg, G.H.J., Van Staalduinen, C.J., Zagwijn, W.H., Zandstra, J.G. 1975. Formaties van het Kwartair en Boven-Tertiair in Nederland. In: Zagwijn, W.H., Van Staalduinen, C.J. (eds.): Toelichting bij geologische overzichtskaarten van Nederland. Rijks Geologische Dienst, Haarlem, 11-56.

McMillan, A.A., Hamblin, R.J.O., Merritt, J.W. 2011. A lithostratigraphical framework for onshore Quaternary and Neogene (Tertiary) superficial deposits of Great Britain and the Isle of Man. British Geological Survey Research Report, RR/10/03, 343 p.

Paepe, R., Baeteman, C. 1979. The Belgian coastal plain during the Quaternary. In: Oele, E., Schüttenhelm, R.T.E., Wiggers, A.J. (eds.), The Quaternary History of the North Sea. Acta Univ. Ups. Symp. Univ. Ups. Annum Quingentesimum Celebrantis: 2, Uppsala, 143-146.

Sindowski, K.H. 1968. Gliederungsmöglichkeiten im sandig ausgebildeten Küsten-Holozän Ostfrieslands. Eiszeitalter und Gegenwart, 19, 209-218.

Stoker, M.S., Balson, P.S., Long, D., Tappin, D.R. 2011. An overview of the lithostratigraphical framework for the Quaternary deposits on the United Kingdom continental shelf. British Geological Survey Research Report, RR/11/03, 48 p.

Weerts, H.J.T. 2003. Beschrijving lithostratigrafische eenheid. Nederlands Instituut voor Toegepaste Geowetenschappen TNO. Utrecht.