Formal (Van Adrichem Boogaert & Kouwe 1993).
Silt- to claystone, light- to dark-grey and light-brown coloured, with abundant carbonaceous laminae which often show pyritised burrows, and with thin sandstone beds (mostly less than 1 meter). The clear sands have fine to medium, subangular to rounded grains. Minor occurrences of medium- to dark-grey claystone and white to light-brown limestone and dolomite are present. Lignite is locally abundant. In some wells (P03-02), abundant fragments of bivalves and gastropods have been encountered.
Deposited in a marginal-marine setting at the landward (backbarrier) position of the beach-barrier deposits of the sandy Kotter and Helder Members. Restricted conditions in a lagoonal setting with storm influences.
Definition of lower boundary
Unconformable with the underlying Vlieland Claystone or Sandstone formations.
Definition of upper boundary
Overlain by the sandy Helder Member of the Vlieland Sandstone Formation.
Generally less than 76 m, but up to 150 m in P03-02.
UK: Humber Group; GER: ?; BEL: -.
latest Berriasian - early Valanginian.
Origin of name
Named after the Helm oil field, block Q01, Dutch offshore sector.
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]). Helm Member. In: Stratigraphic Nomenclature of the Netherlands, TNO – Geological Survey of the Netherlands. Accessed on [DATE] from http://www.dinoloket.nl/en/stratigraphic-nomenclature/helm-member.