Formal (NAM & RGD 1980). Amended (Van Adrichem Boogaert & Kouwe 1993).
Sequence of predominantly medium to dark greenish-grey, locally light grey or mottled red, silty, locally slightly calcareous claystones, with locally minor intercalated thin, fossiliferous limestones, siltstones, and rare nodular, calcitic or dolomitic anhydrite beds.
Predominantly terrestrial, lacustrine to restricted lagoonal, coastal-plain setting with intermittent brackish-water influence. Marine influence seems to have been most significant in the basal parts of the member.
Definition of lower boundary
Conformable contact with more sandy sediments of the Aerdenhout Member, or the unconformable contact with the Altena Group.
Definition of upper boundary
Conformably overlain by the sandy Bloemendaal Member in blocks Q01 and K15. Otherwise, the top is represented by the conformable contact with sandier sediments of the Santpoort Member. In Subhercynian/ Laramide-inverted basin structures an unconformable contact with the Chalk or Lower North Sea Group can be seen. Locally, the Neomiodon Claystone Member or Rijnland Group can unconformably overlie the Fourteens Claystone Member.
UK: Humber Group; GER: ?; BEL: -.
early Kimmeridgian - early Berriasian.
Origin of name
Named after the Broad Fourteens, an offshore shoal west of the Dutch province of Noord-Holland.
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..
TNO-GDN ([YEAR]). Fourteens Claystone Member. In: Stratigraphic Nomenclature of the Netherlands, TNO – Geological Survey of the Netherlands. Accessed on [DATE] from https://www.dinoloket.nl/en/stratigraphic-nomenclature/fourteens-claystone-member.