Oxfordian (stage)
Oxfordian | |
---|---|
Ammonite Cardioceras redcliffense . | |
Lower boundary GSSP candidate section(s) | |
Upper boundary definition | |
Upper GSSP ratified | 2021[2] |
The Oxfordian is, in the
Stratigraphic definitions
The Oxfordian Stage was called "Clunch Clay and Shale" by William Smith (1815–1816); in 1818 W. Buckland described them under the unwieldy title "Oxford, Forest or Fen Clay". The term Oxfordian was introduced by Alcide d'Orbigny in 1844. The name is derived from the English city of Oxford,[4] where the beds are well developed, but they crop out almost continuously from Dorset to the coast of Yorkshire, generally forming low, broad valleys. They are well exposed at Weymouth, Oxford, Bedford, Peterborough, and in the cliffs at Scarborough, Red Cliff and Gristhorpe Bay. Rocks of this age are found also in Uig and Skye.[5]
The base of the Oxfordian Stage is defined as the point in the stratigraphic record where the
In the Tethys domain, the Oxfordian contains six ammonite biozones:
- zone of Epipeltoceras bimammatum
- zone of Perishinctes bifurcatus
- zone of Gregoryceras transversarium
- zone of Perisphinctes plicatilis
- zone of Cardioceras cordatum
- zone of Quenstedtoceras mariae
References
Notes
- ^ "International Chronostratigraphic Chart" (PDF). International Commission on Stratigraphy.
- ^ "Global Boundary Stratotype Section and Point". International Commission of Stratigraphy. Retrieved 25 July 2021.
- ^ "Stratigraphic Chart 2022" (PDF). International Commission on Stratigraphy. February 2022. Retrieved 22 April 2022.
- ^ Oxfordian is a word meaning "from Oxford" (see wiktionary:Oxfordian).
- ^ public domain: Howe, John Allen (1911). "Oxfordian". In Chisholm, Hugh (ed.). Encyclopædia Britannica. Vol. 20 (11th ed.). Cambridge University Press. p. 415. One or more of the preceding sentences incorporates text from a publication now in the
Literature
- Brongniart, A.; 1829: Tableau théorique de la succession et de la disposition la plus générale on Europa, des terrains et roches, qui composent l'écorce de la terre, Paris.(in French)
- Gradstein, F.M.; Ogg, J.G. & Smith, A.G.; 2004: A Geologic Time Scale 2004, Cambridge University Press.
External links
- GeoWhen Database - Oxfordian
- Jurassic-Cretaceous timescale, at the website of the subcommission for stratigraphic information of the ICS
- Stratigraphic chart of the Upper Jurassic, at the website of Norges Network of offshore records of geology and stratigraphy