Code
NUNAWAAL
Status
Formal (Weerts 2003).
Lithological description
Dark grey to brownish grey clay and detritus, silty, partly distinctly layered with very fine sand. Locally, thick intercalations of medium sand derived from nearby coversand. Abundant ostracods.
Depositional setting
Brackish-water lagoonal with deep eroding channels.
Definition of lower boundary
Sharp contact with organo-clastic sediment (Flevomeer Bed, Nieuwkoop Formation), tidal sand and clay (Wormer Member, Naaldwijk Formation) or coversand (Wierden Member, Boxtel Formation).
Definition of upper boundary
Sharp contact with lagoonal or lacustrine clay (Zuiderzee and IJsselmeer Beds, Naaldwijk Formation).
Thickness indication
Up to about 2 m.
Geographical distribution
In and around Lake IJssel in the central Netherlands.
Regional correlation
North Sea: not present; UK: not present; GER: not present; BEL: not present.
Age
Holocene (Meghalayan).
Type section
Well:
Not yet determined.
Depth (thickness) AH:
Not yet determined.
Origin of name
Early Medieval inland lake northeast of Amsterdam.
Previous name(s)
Almere deposit (Westland Formation).
Reviewed by (date)
Wim Dubelaar (2018), Sytze van Heteren (2019).
References
Weerts, H.J.T. 2003. Beschrijving lithostratigrafische eenheid. Nederlands Instituut voor Toegepaste Geowetenschappen TNO. Utrecht.
Cite as
TNO-GDN ([YEAR]). Almere Bed. In: Stratigraphic Nomenclature of the Netherlands, TNO – Geological Survey of the Netherlands. Accessed on [DATE] from http://acc.dinoloket.nl/en/stratigraphic-nomenclature/almere-bed.