Formal (Munsterman et al. 2012).
Moderately to well-sorted, greenish-grey, slightly argillaceous, occasionally calcite cemented, glauconitic sandstones. Sediments show bioturbation and are locally pyritic, lignitic, and/or characterised by shell debris.
Shallow marine environment, ranging from offshore to lower shore face.
Definition of lower boundary
With the Oyster Ground Member (Skylge Formation) is marked by a sharp downward increase in GR-log readings.
Definition of upper boundary
With the Scruff Spiculite Member is marked by funnel-shaped GR-log pattern, resulting from the upward decreasing clay content.
UK: Humber Group; GER: ?; BEL: -.
Origin of name
Named after the shoal in the western part of the Wadden island Terschelling.
Munsterman, D.K., Verreussel, R.M.C.H., Mijnlieff, H.F., Witmans, N., Kerstholt-Boegehold, S. & Abbink, O.A. 2012. Revision and update of the Callovian-Ryazanian Stratigraphic Nomenclature in the northern Dutch Offshore, i.e. Central Graben Subgroup and Scruff Group. Netherlands Journal of Geosciences-Geologie en Mijnbouw, 91 (4), 555-590.
TNO-GDN ([YEAR]). Noordsvaarder Member. In: Stratigraphic Nomenclature of the Netherlands, TNO – Geological Survey of the Netherlands. Accessed on [DATE] from http://www.dinoloket.nl/en/stratigraphic-nomenclature/noordsvaarder-member.