Swalmen Member

Formal (Van Adrichem Boogaert & Kouwe 1997).
Lithological description

Mostly an alternation of thin sand layers and humic clay layers, containing small pieces of coalified plant remains and locally, in its upper reaches, thin lignite beds. The sand is yellowish grey-brown. The clay is hard and flaky, light to dark grey-brown to black, and contains pyrite nodules. The lower sandy layers, locally contain gravel and may contain shells and/or glauconite. Locally, very characteristic, bright red and olive-green spots and flames occur in the clays.

Depositional setting

Brackish to lagoonal. The lignite beds point to the occasional occurrence of paralic or limnic conditions.

Definition of lower boundary

Sharp lithologic and log break due to the unconformable contact with the underlying Houthem Formation of the Chalk Group.

Definition of upper boundary

Sharp lithologic transition to the glauconitic sand of the Orp Member.

Thickness indication
Up to 60 m.
Geographical distribution
Regional correlation
UK: no equivalent; GER: Antweiler Formation; BEL: Opglabbeek Formation (Maréchal & Laga 1988).
late Paleocene (Selandian).
Depth (thickness) AH:
499 - 530 m AH (31 m)
Origin of name
Named after the village of Swalmen in the southeast of the Netherlands.
Previous name(s)
Heers Sand Member (NAM & RGD 1980). Limnic Montien (Pannekoek 1956). Lutterade Clay (Member) of the Maasmechelen Formation (RGD 1983).
Reviewed by (date)
Geert-Jan Vis (2019).
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.
Pannekoek, A.J. (ed.) 1956. De geologische geschiedenis van Nederland. Toelichting bij de geologische overzichtskaart van Nederland op de schaal 1:200.000. Staatsdrukkerij- en uitgeverijbedrijf, 's-Gravenhage.
RGD 1983. Geologische en hydrologische inventarisatie van tertiaire en onder-kwartaire afzettingen in Midden-Nederland t.b.v. ondergrondse opslag en winning van warm water. Public report 83KA20EX, RGD report 10371, 137 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.
Cite as
TNO-GDN ([YEAR]). Swalmen Member. In: Stratigraphic Nomenclature of the Netherlands, TNO – Geological Survey of the Netherlands. Accessed on [DATE] from https://www.dinoloket.nl/en/stratigraphic-nomenclature/swalmen-member.