Code
ATWDL
Status
Formal (NAM & RGD 1980).
Lithological description
Grey, occasionally silty, claystones often containing characteristic clay-ironstone concretions and/or iron ooliths.
Depositional setting
Open marine.
Definition of lower boundary
Upon the bituminous claystones of the Posidonia Shale Formation.
Definition of upper boundary
First of the more calcareous, silty to sandy beds of the overlying Middle Werkendam Member.
Thickness indication
Up to 750 m (K14-FA-106).
Geographical distribution
Regional correlation
UK: West Sole Group; GER: Dogger Group; BEL: -.
Age
Toarcian - early Bajocian.
Holostratotype
Well:
Depth (thickness) AH:
2007 - 2205 m (198 m)
Origin of name
None.
Previous name(s)
None.
Reviewed by (date)
Sander Houben (2017).
References
NAM & RGD 1980. Stratigraphic nomenclature of The Netherlands. Verhandelingen van het Koninklijk Nederlands Geologisch Mijnbouwkundig Genootschap 32, 77 p.
Cite as
TNO-GDN ([YEAR]). Lower Werkendam Member. In: Stratigraphic Nomenclature of the Netherlands, TNO – Geological Survey of the Netherlands. Accessed on [DATE] from http://acc.dinoloket.nl/en/stratigraphic-nomenclature/lower-werkendam-member.