Code
NUNAWAYS
Status
Formal (Weerts 2003).
Lithological description
Light brown to black clay, soft on the lake bed, firm on land, silty, humic, with organic detritus. Locally, clear lamination.
Depositional setting
Freshwater lacustrine, in former tidal areas cut off from the sea by man.
Definition of lower boundary
Commonly, sharp contact with lagoonal sand and clay (Zuiderzee Bed, Walcheren Member, Naaldwijk Formation).
Definition of upper boundary
Exposed at the surface or on the lake bed.
Thickness indication
Up to about 1.5 m.
Geographical distribution
Deeper parts of Lake IJssel in the central Netherlands, and a small man-made lake in the southwestern Netherlands.
Regional correlation
North Sea: not present; UK: not present; GER: not present; BEL: not present.
Age
Holocene (Meghalayan, post-1932 AD).
Holostratotype
Comments:
Tentative location: a borehole in Lake IJssel, central Netherlands.
Hypostratotype
Comments:
Tentative location: B49B1840 (Bergen op Zoom), interval 0.94 - 2.55 m below land surface.
Origin of name
IJsselmeer, an inland lake northeast of Amsterdam, formed upon artificial closure of the Zuiderzee inland sea in 1932.
Previous name(s)
IJsselmeer mud (Ente et al. 1986).
Reviewed by (date)
Wim Dubelaar (2018), Sytze van Heteren (2019).
References
Ente, P.J., Koning, J., Koopstra, R. 1986. De bodem van Oostelijk Flevoland. Flevobericht 258, Rijksdienst voor de IJsselmeerpolders, Lelystad.
Weerts, H.J.T. 2003. Beschrijving lithostratigrafische eenheid. Nederlands Instituut voor Toegepaste Geowetenschappen TNO. Utrecht.
Cite as
TNO-GDN ([YEAR]). IJsselmeer Bed. In: Stratigraphic Nomenclature of the Netherlands, TNO – Geological Survey of the Netherlands. Accessed on [DATE] from http://acc.dinoloket.nl/en/stratigraphic-nomenclature/ijsselmeer-bed.