Middle Graben Formation

SLCM

Formal (NAM & RGD 1980). Amended (Van Adrichem Boogaert & Kouwe 1993).

Grey, locally very silty, carbonaceous claystones. In the northern part of the F-quadrant one thick or locally two sandstone beds may be intercalated. At the base of the formation three thin but distinct coal seams occur.

Lacustrine to marginal marine embayment.

Placed below the base of the lowermost distinct coal seam, immediately overlying thick sand beds.

Conformable contact with the marine claystones of the Kimmeridge Clay Formation or barrier sands of the Upper Graben Formation in the northern part of the Dutch Central Graben. To the south it is overlain by the coal-bed dominated Puzzle Hole Formation. The transition from the Middle Graben Formation to the Puzzle Hole Formation is gradual.

500 m.

UK: Humber Group; GER: ?; BEL: -.

early Oxfordian - middle Oxfordian.

Named after the Central Graben.

None.

Sander Houben (2017).

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. 1993. Stratigraphic nomenclature of The Netherlands; revision and update by RGD and NOGEPA, Section G, Upper Jurassic and Lower Cretaceous. Mededelingen Rijks Geologische Dienst, 50, 1-80..