Millstone Grit Formation

Formal (Van Adrichem Boogaert & Kouwe 1995).
Lithological description

Succession of interbedded grey, white and brown sandstones, and dark-grey, partly carbonaceous mudstones and siltstones. Individual sandstone beds are more than 10 m thick, but stacked beds can amount up to 80 m. The sands are mainly fine- to medium-grained, with occasional gravelly intercalations. Sandstone beds can have sharp tops and bottoms, or grade into mudstones. Mudstone-dominated intervals with thin silt- and fine-grained sandstone intercalations can be up to 100 m thick. The formation consists of stacked coarsening-upward cycles, generally starting with a basal marine interval. (Cameron 1993).
In the Dutch reference section, some 1 - 4 m thick argillaceous limestone beds and tuff layers are intercalated. Sandstone beds are up to 17 m thick here.

Depositional setting

Sheet-delta systems with brief marine incursions (Collinson 1988). Sandstones: delta-front deposits with mouth bars, and distributary-channel fills. Fines: pro-delta turbidites, or settled from suspension. The Millstone Grit Formation reflects a depositional regime, intermediate between the basin facies of the Epen Formation and the delta-plain facies of the Klaverbank Formation. As a result of the north-to-south regressive development of the lower Pennsylvanian - upper Mississippian (Namurian-Westphalian) in the Silverpit Basin area, the two formations are partial age equivalents.

Definition of lower boundary

Placed at the base of the lowermost sandstone interval which is more than 10 m thick.

Definition of upper boundary

Placed below the Klaverbank Formation at the base of the sandstone bed immediately underlying the first definite coal seam, or the base of that coal seam where such a sandstone is not developed (Cameron 1993).

Thickness indication
Up to 162 m.
Geographical distribution
Regional correlation
UK: Millstone Grit Formation; GER: ?; BEL: Andenne Formation.
Serpukhovian - Bashkirian.
Depth (thickness) AH:
1609 - 1717 m (108 m)
Information on this unit from the Dutch continental shelf is still scanty.
Depth (thickness) AH:
2598 - 2708 m (110 m)
Origin of name
The name Millstone Grit was introduced by J. Whitehurst in 1778, for a succession of coarse-grained sandstones and interbedded mudstones, which are found in many outcrops throughout the Central Pennines of England. Four reference sections have been designated for the UK Southern North Sea Basin by Cameron (1993).
Previous name(s)
Reviewed by (date)
Tom van Hoof (2017).
Cameron, T.D.J. 1993. Carboniferous and Devonian of the Southern North Sea. ln: Knox. R.W.0'8. & Cordey, W.G. (eds.) Lithostratigraphic nomenclature of the UK North Sea 5, British Geological Survey, Nottingham, 94 p.
Collinson, J.D. 1988. Controls on Namurian sedimentation in the Central Province basins of northern England - ln: Besly, B.M. & Kelling, G. (eds.), Sedimentation in a synorogenic basin complex - the Upper Carboniferous of Northwest Europe, 83-101. Blackie, Glasgow.
Van Adrichem Boogaert, H.A. & Kouwe, W.F.P. 1995. Stratigraphic nomenclature of The Netherlands, revision and update by RGD and NOGEPA, Section C, Silesian. Mededelingen Rijks Geologische Dienst, 50, 1-40.
Cite as
TNO-GDN ([YEAR]). Millstone Grit Formation. In: Stratigraphic Nomenclature of the Netherlands, TNO – Geological Survey of the Netherlands. Accessed on [DATE] from