Epen Formation

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

Succession of dark-grey to black mudstones with a few intercalations of grey and buff, (sub-) angular, moderately- to well-sorted, very fine- to medium-grained sandstone. Coal seams are absent, but disperse carbonaceous matter is locally abundant. The interval consists of a number of stacked coarsening-upward sequences (with funnel-shaped GR-log patterns), between 50 and 300 metres thick. Shaly mudstones, some containing marine fossils, dominate the basal and middle parts of each sequence. In the area south of the Mid-North Sea High some carbonate beds can be intercalated e.g. well A14-01.

Depositional setting

Cyclic repeated delta progradation into a predominantly lacustrine basin.

Definition of lower boundary

Along the northern margin of the London-Brabant Massif, the Geverik Member (consisting of basal bituminous shale) rests on the carbonates of the Carboniferous Limestone Group. In well Geverik-1 this transition is gradual and apparently conformable, but elsewhere this contact can be unconformable, locally lacking the basal shale (well S02-02). Well A14-01 shows the Mid-North Sea High succession, where the Yoredale Formation grades upwards into the Epen Formation. The boundary has been placed at the top of the uppermost carbonate-dominated sequence.

Definition of upper boundary

With the Baarlo Formation placed at the base of the first prominent coal seam. In the northwestern Netherlands offshore, the formation is overlain by the Millstone Grit Formation. The boundary has been placed at the base of the lowermost thick sandstone bed of the sandstone-dominated Millstone Grit succession. It is a diachronous boundary, which becomes younger from north to south. Therefore these formations are also partial lateral equivalents.

Thickness indication
Up to 895 m.
Geographical distribution
Regional correlation
UK: Millstone Grit Formation & Bowland/Edale Shale Formation; GER: Walhorn Formation; BEL: Chokier Formation.
Serpukhovian - Bashkirian.
Depth (thickness) AH:
2438 - 4303 m (1865 m)
Depth (thickness) AH:
2927 - 4644.5 m (1717.5 m)
Depth (thickness) AH:
672 - 992 (320 m)
Origin of name
Named after the village of Epen in the south of the province of Limburg. Several outcrops of this formation exist in the valley of the river Geul near Epen.
Previous name(s)
Named by some operators as 'Namen Shale'.
Reviewed by (date)
Tom van Hoof (2017).
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]). Epen Formation. In: Stratigraphic Nomenclature of the Netherlands, TNO – Geological Survey of the Netherlands. Accessed on [DATE] from https://www.dinoloket.nl/en/stratigraphic-nomenclature/epen-formation.