Hellevoetsluis Formation

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

Succession of interbedded 1 to 15 m thick sandstone beds and silty to sandy, carbonaceous mudstones containing occasional coal seams. Sands are predominantly grey or white, fine- to coarse-grained, well- to moderately-sorted and subangular and occur in sheets and channel fills, locally stacked up to 30 m thick, with frequent metre-scale mudstone intercalations.
Mudstone intervals are predominantly greenish-grey or beige, frequently with purple or red-brown horizons in the their upper parts. Coal seams are rare, associated with grey claystone intervals of 5 to 55 m thick.

Depositional setting

Amalgamated braided fluvial channel fills, with overbank deposits (crevasses, sheet floods).
Poorly- or fairly-drained flood-plains and with local swamps. Sandstone-dominated and mudstone-dominated intervals can be correlated on a local to regional scale, implying a depositional cyclicity.

Definition of lower boundary

Contact with the underlying Maurits Formation is marked by the incursion of thick, argillaceous matrix-poor sandstone beds, commonly in combination with a decrease in the frequency of coal seams.

Definition of upper boundary

Marked by a transition towards thick, greenish-grey or orange-red mudstones with fewer intercalated sheet sandstones, typical for the overlying Strijen Formation. The boundary is defined at the base of the first mudstone-dominated interval of more than 60 m thick. This diachronous change occurred earlier in the centre of the basin than along its margins.

Thickness indication
Up to 414 m.
Geographical distribution
Regional correlation
UK: ? / GER: ? / BEL: ?.
Depth (thickness) AH:
2957 - 3214 m (257 m)
Depth (thickness) AH:
1725 - 1880 m (155 m)
Depth (thickness) AH:
3766 - 3881 m (115 m)
Depth (thickness) AH:
2950 - 3033 m (83 m)
Depth (thickness) AH:
2765 - 3023 m (258 m)
Depth (thickness) AH:
3355 - 3516 m (161 m)
Origin of name
Named after the Dutch town of Hellevoetsluis in the southwest of the province of Zuid-Holland, where the type well is located.
Previous name(s)
Informal reffered to by some oil companies as the 'Twente Sandstone'.
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]). Hellevoetsluis Formation. In: Stratigraphic Nomenclature of the Netherlands, TNO – Geological Survey of the Netherlands. Accessed on [DATE] from https://www.dinoloket.nl/en/stratigraphic-nomenclature/hellevoetsluis-formation.