Middle North Sea Group Explained

bgcolor="Lightgrey" colspan="3"

Marine
Veldhoven Formation VE	Someren Member VESO
	Voort Member VEVO
	Wintelre Member VEWI
Rupel Formation RU	Bilzen Member RUBI	Berg Member RUBIBE
		Kerniel Member RUBIKE
		Kleine Spouwen Member RUBIKS
	Boom Member RUBO	Brinkheurne Member RUBOBR
		Winterswijk Member RUBOWI
	Eigenbilzen Member RUEB
	Ratum Member RURA	Ootmarsum Member RURAOO
Tongeren Formation TO	Goudsberg Member TOGO
	Klimmen Member TOKL
	Zelzate Member TOZE	Bassevelde Member TOZEBA
		Ruisbroek Member TOZERU
		Watervliet Member TOZEWA

The Middle North Sea Group (abbreviation: NM) is a group of geologic formations in the Dutch subsurface, part of the North Sea Supergroup. The three formations of this group form a thick sequence of sediments in the Dutch subsurface, they crop out in parts of the southern Netherlands. The Middle North Sea Group was deposited from the late Eocene to late Oligocene, between 37 and 23 million years ago.

Its three formations are (from old to young) the Tongeren, Rupel and Veldhoven Formations. The Tongeren Formation has a continental to paralic facies, the other two consist mainly of shallow marine clays and sands.