Code
NM
Status
Formal (NAM & RGD 1980). Amended (Van Adrichem Boogaert & Kouwe 1997). The NU-Group, NM-Group and NL-Group can be taken together as North Sea Supergroup (code N).
Lithologische beschrijving
Sands, silts and clays of a predominantly marine origin. The sands have their main distribution along the southern margin of the North Sea Basin.
Afzettingsmilieu
Predominantly marine. Lagoonal and coastal-plain environments only found in the area of South Limburg.
Definitie ondergrens
Rests with a distinct unconformity on the Lower North Sea Group (or older sediments) over most of the Netherlands onshore area. In the area of the Zuiderzee Low and the Voorne Trough, the lower boundary is poorly defined.
Definitie bovengrens
Unconformably overlain by the Breda Formation, except possibly in the Roer Valley Graben.
Dikte indicatie
Up to ~550 m.
Geografische verbreiding
Regionale correlatie
UK: ~Westray Group; GER: no equivalent group; BEL: Tongeren Group & Rupel Group.
Ouderdom
Priabonian - Chattian, possibly Aquitanian.
Holostratotype
Well:
Depth (thickness) AH:
860 - 1229 m (369 m)
Parastratotype
Well:
Depth (thickness) AH:
619 - 779 m (160 m)
Hypostratotype
Well:
Depth (thickness) AH:
867 - 1410 m (543 m)
Oorsprong naam
Named after the North Sea. The prefix ‘Middle’ has been added to designate the middle (approximately Oligocene) part of the clastic sequence on top of the Chalk Group.
Vorige benaming(en)
None.
Gereviewed door (datum)
Dirk Munsterman (2018).
Referenties
NAM & RGD 1980. Stratigraphic nomenclature of The Netherlands. Verhandelingen van het Koninklijk Nederlands Geologisch Mijnbouwkundig Genootschap 32, 77 p.
Van Adrichem Boogaert, H.A. & Kouwe, W.F.P. 1997. Stratigraphic nomenclature of The Netherlands, revision and update by RGD and NOGEPA, Section I, Tertiary. Mededelingen Rijks Geologische Dienst, 50, 1-39.
Cite as
TNO-GDN ([YEAR]). Middle North Sea Group. In: Stratigraphic Nomenclature of the Netherlands, TNO – Geological Survey of the Netherlands. Accessed on [DATE] from https://www.dinoloket.nl/en/stratigraphic-nomenclature/middle-north-sea-group.