Formal (NAM & RGD 1980). Amended (Van Adrichem Boogaert & Kouwe 1997).
Generally dark-green, hard, flaky clay, somewhat silty, containing pyrite, mica and much glauconite. The basal part of the member can be marly and of a lighter colour. In the eastern Netherlands (closer to the palaeo-coastline) the clay is fine-sandy to silty and its colour greenish, also brown. Many traces of bioturbation.
Open-marine environment, the water depth was probably some tens to hundreds of metres.
Definition of lower boundary
Somewhat gradual transition to the underlying Gelinden Member (southeastern Netherlands). On gamma-ray logs the Liessel Member displays higher values than the Gelinden Member; on resistivity logs the reverse is shown. Elsewhere in the Netherlands the Liessel Member overlies the Orp Member. When the Orp Member is also absent, the Liessel Member unconformably overlies deposits of Mesozoic or older age.
Definition of upper boundary
Somewhat gradual transition to the overlying sandy Reusel Member (southern part of the Netherlands). Elsewhere this unit is overlain by the Oosteind Member, which has lower gamma-ray and spontaneous potential readings. Against the flanks of the ‘Southern Early Tertiary High’ and locally in the northeastern Netherlands, the unit is unconformably overlain by younger deposits.
UK: Maureen Formation, Lista Formation; GER: not present; BEL: in the southeastern Netherlands this member corresponds with the Waterschei Member of the Hannut Formation. The latter is part of the Landen Group (Marechal & Laga 1988).
late Paleocene (Thanetian).
Origin of name
Named after the villag of Liessel in the south of the Netherlands.
Landen Clay Member (NAM & RGD 1980). New name, renamed because Landen is already used as a formation name.
Maréchal, R., Laga, P. (eds.) 1988. Voorstel lithostratigrafische indeling van het Paleogeen - Nationale Commissies voor Stratigrafie. Commissie: Tertiair, Belgische Geologische Dienst, Brussel, 208 p.
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. 1997. Stratigraphic nomenclature of The Netherlands, revision and update by RGD and NOGEPA, Section I, Tertiary. Mededelingen Rijks Geologische Dienst, 50, 1-39.
TNO-GDN ([YEAR]). Liessel Member. In: Stratigraphic Nomenclature of the Netherlands, TNO – Geological Survey of the Netherlands. Accessed on [DATE] from http://www.dinoloket.nl/en/stratigraphic-nomenclature/liessel-member.