Status
Formal (Felder 1975). Amended (Felder & Bosch 2000).
Lithological description
White, chalky limestones, containing thin, grey to green clay laminae. Some glauconite can occur in the basal interval.
Depositional setting
Similar to the Ommelanden Formation, this formation was deposited under relatively stable, low-energy conditions in carbonate-shelf and upper bathyal environments. The rocks consist essentially of pelagic, biogenic remains, which settled from suspension. A variety of subfacies has been recognised, reflecting variation in sedimentation rate and water depth. In many localities Campanian-Maastrichtian fossil associations indicate considerably shallower water conditions than Turonian-Santonian associations (e.g, lower plankton/benthos ratio). The Houthem Formation represents post-inversion deposits which onlap onto and overstep inverted basins.
Definition of lower boundary
Usually onlapping Jurassic or Triassic rocks. In south Limburg the formation rests upon the Maastricht Formation. A clay bed is sometimes observed at the boundary between the Cretaceous and the Paleocene.
Definition of upper boundary
Clear boundary with overlying sands and clays of the North Sea Super Group, the top of the formation is expressed on wire-line logs by a low gamma-ray response and a high acoustic velocity.
Thickness indication
20 to locally over 100 m.
Geographical distribution
The Houthem Formation is the onshore equivalent of the Ekofisk Formation. It occurs locally in the northern and southern Netherlands onshore area (West Netherlands Basin and the Central Netherlands Basin, Roer Valley Graben, South Limburg).
Regional correlation
UK: Ekofisk Formation; GER: no equivalent; BEL: Houthem Formation.
Holostratotype
Well:
Outcrops in the south of the Geul Valley, near the village of Houthem.
Origin of name
Named after the village of Houthem.
Previous name(s)
Previously part of 'Chalk of Maastricht' or 'Maastrichts Krijt' (Uhlenbroek 1912).
Reviewed by (date)
Mark Geluk, Geert-Jan Vis (2017).
References
Felder, W.M. 1975. Lithostratigrafie van het Boven‑Krijt en het Dano‑Montien in Zuid‑Limburg en het aangrenzende gebied. In: Zagwijn, W.H. & Van Staalduinen C.J. (eds.), Toelichting bij geologische overzichtskaarten van Nederland, Rijks Geologische Dienst, Haarlem, 63‑72.
Felder, W.N. & Bosch, P.W. 2000. Het Krijt van Zuid-Limburg. NITG-TNO, Geologie van Nederland 5, 190 p.
Uhlenbroek, G.D. 1912. Het Krijt van Zuid-Limburg. Jaarverslag der Rijksopsporing van Delfstoffen over 1911. Den Haag, 48-56.
Cite as
TNO-GDN ([YEAR]). Houthem Formation. In: Stratigraphic Nomenclature of the Netherlands, TNO – Geological Survey of the Netherlands. Accessed on [DATE] from https://www.dinoloket.nl/en/stratigraphic-nomenclature/houthem-formation.
