Texel Formation CKTX

 

Premise Definition after NAM and RGD (1980) . The lithological affix has been left out since the formation does not consist exclusively of chalk.
Derivatio nominis Named after the Dutch Wadden island of Texel, south of the type well L12-02.
Type section Location map See figure (pdf)
  Well L12-02 (pdf)
  Location N 53°20'24.5
E 04°45'42.6
  Depth 2324 to 2406 m
  Length 82 m along hole
  Reference .(amended after NAM and RGD (1980) )
Additional section Location map See figure (pdf)
  Well De Lier-2 (pdf)
  Location N 51°58'43.9
E 04°13'39.4
  Depth 1081 to 1127 m
  Length 46 m along hole
  Reference NAM and RGD (1980)
Definition Interval of white to light-grey, locally pinkish limestones and marly chalks with some marly intercalations. In the south, glauconitic sands are present in the lowermost part of the formation.
Upper Boundary The upper boundary with the Ommelanden Chalk normally coincides with the top of the Plenus Marl Member, which is expressed on wire-line logs by a peak of high gamma-ray response and a lower acoustic velocity.
Lower Boundary The contact with the underlying Holland Formation is usually distinct; the marls and marly claystones of the Holland Formation exhibit a higher gamma ray response and lower acoustic velocity. In the West Netherlands Basin and the Broad Fourteens Basin the Holland HollandFormation is much thicker, and the transition is more gradual. In the vicinity of the Mid North Sea High Elbow Spit High and over salt domes the unit locally rests unconformably upon deposits of the Zechstein Group, the Lower Germanic Trias Group or the Upper Germanic Trias Group.
Distribution . The formation is widespread in the southern North Sea and the Netherlands onshore area, where its distribution roughly coincides with that of the Chalk Group. The formation's depositional realm did not include the northern flanks of the London-Brabant Massif and Rhenish Massif. These were not reached by the transgression until the Campanian-Maastrichtian. The formation is also absent on the crest of the Mid-North Sea High Elbow Spit High, and in areas where the main inversion event occurred during the Santonian-Campanian (Subhercynian phase). The formation is exposed very locally in the Achterhoek, east of Winterswijk (van Adrichem Boogaert (1975) ; Witte et al (1992) ).
Age Cenomanian. In the West Netherlands Basin and the Broad Fourteens Basin Chalk deposition may have commenced as early as Albian. Characteristic markers are the planktonic Foraminifera Rotalipora cushmani, R. appenninica, R, reicheli, R. brotzeni and Favusella washitenis. Numerous benthic Foraminifera, both agglutinating (Flourensina mariae, Arenobulimina advena, Pseudotextulariella cretosa, Crenoverneuilina intermedia) and calcareous (Gavelinella intermedia, G. cenomanica, Lingulogavelinella jarzevae) are frequently encountered. Some Ostracoda (Protocythere consobrina, Cornicythereis larivourensis, Neocythere steghausi and Cythereis thoerenensis) have a diagnostic value as well. There is a distinct change in the composition of the dinoflagellate cyst assemblages across the Middle-Upper Albian boundary. Some species, such as Apteodinium maculatum grande, Gonyaulacysta helicoidea and Ovoidinium scabrosum, have their range top in the upper(most) Albian-lowermost Cenomanian or have an acme in this interval. Several other species which appear in the Upper Albian, have their top-occurrence in the Cenomanian: Epelidosphaerrdia spinosa, which is a marker for the Middle-Upper Cenomanian boundary and Carpodinium obliquicostatum, Endoceratium dettmanniae and Pterodinium cingulatum granulatum which range into the Upper Cenomanian. Markers for the Cenomanian-Turonian boundary are Litosphaeridium siphoniphorum and Gonyaulacysta cassidata.
Subdivision  
  Three formal members have been distinguished in the Texel Formation:
  CK Chalk Group
  CKTX Texel Formation
  CKTXP Plenus Marl Member
  CKTXM Texel Marlstone Member
  CKTXG Texel Greensand Member
References See References Upper Cretaceous

Van Adrichem Boogaert, H.A. & Kouwe, W.F.P., 1993-1997. [Stratigraphic unit]. In: Stratigraphic Nomenclature of the Netherlands.
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