Oploo formation

Code
CKOP
Status
Informal. New formation proposed by Gras & Geluk (1999), first used in NITG-TNO (2001).
Lithological description

The upper part consists of fine grained, locally argillaceous sandstones. The lower part consists of a cyclic alternation of glauconitic and argillaceous sandstones, grading into bioclastic limestones.

Depositional setting

Shallow marine environment, during tectonic inversion.

Definition of lower boundary

Rests unconformably on older rocks of Triassic, Permian and Carboniferous age.

Definition of upper boundary

Nature of the contact with the overlying Vaals Formation is gradual.

Thickness indication
As a result of syndepositional tectonic movements the thickness of the formation varies considerably, up to 328 m (Oploo-16).
Geographical distribution
Occurs on the northern part of the Peel and the Venlo Blocks and in the transition zone with the Maasbommel High. Correlatates with the Aachen Formation to the south. Further north it grades into the Ommelanden Formation. (Gras & Geluk 1999).
Regional correlation
UK: Lamplugh and Jukes formations (offshore); GER: Aachen Formation; BEL: Aachen Formation.
Age
Santonian.
Holostratotype
Well:
B46C0003 (Oploo-16)
Depth (thickness) AH:
822 - 1049 m (227 m; base not reached)
Comments:
The type area is the Oploo-16 well on the Peel Block. Despite the fact that this well has not been logged, detailed biostratigraphic analyses exist (NITG 1998a, b).
Origin of name
Named after the village of Oploo.
Previous name(s)
In the past these deposits were considered Aachen Formation and/or Vaals Formation (Felder & Bosch 2000; Peelcommissie 1963).
Reviewed by (date)
Mark Geluk, Geert-Jan Vis (2017).
References
Felder, W.M. & Bosch, P.W. 2000. Het Krijt van Zuid-Limburg. NITG-TNO, Geologie van Nederland 5, 192 p.
Gras, R. & Geluk, M.C. 1999. Late Cretaceous-Early Tertiary sedimentation and tectonic inversion in the southern Netherlands. Geologie en Mijnbouw 78, 1-19.
NITG 1998a. De resultaten van palynologisch onderzoek naar de ouderdom en het afzettingsmilieu van boring 46C003 (Oploo-16), traject 491–670 m – NITG-TNO, Haarlem. Unpublished Internal Report, NITG 98–14-B.
NITG 1998b. Biostratigrafische interpretatie van een Boven-Krijt traject van boring 46C003 (Oploo-16) – NITG-TNO, Haarlem. Unpublished Internal Report, NITG 98–199-B.
NITG-TNO (2001) Explanation to map sheets Xlll and XIV
Breda-Val kenswaard and Oss-Roermond. NITG-TNO (Utrecht) 150 p.
Peelcommissie 1963. Rapport van de Peelcommissie. Verhandelingen Koninklijk Nederlands
Geologisch Mijnbouwkundig Genootschap, Mijnbouwkundige Serie 5, 133 p.
Cite as
TNO-GDN ([YEAR]). Oploo formation. In: Stratigraphic Nomenclature of the Netherlands, TNO – Geological Survey of the Netherlands. Accessed on [DATE] from http://www.dinoloket.nl/en/stratigraphic-nomenclature/oploo-formation.