The Santonian is an age in the geologic timescale or a chronostratigraphic stage. It is a subdivision of the Late Cretaceous Epoch or Upper Cretaceous Series. It spans the time between 86.3 ± 0.7 mya (million years ago) and 83.6 ± 0.7 mya. The Santonian is preceded by the Coniacian and is followed by the Campanian.
|Regional usage||Global (ICS)|
|Time scale(s) used||ICS Time Scale|
|Time span formality||Formal|
|Lower boundary definition||FAD of the Inoceramid Bivalve Cladoceramus undulatoplicatus|
|Lower boundary GSSP||Olazagutia, Spain|
|GSSP ratified||January 2013|
|Upper boundary definition||Not formally defined|
|Upper boundary definition candidates||LAD of the Crinoid Marsupites testudinarius|
|Upper boundary GSSP candidate section(s)|
The base of the Santonian Stage is defined by the appearance of the inoceramid bivalve Cladoceramus undulatoplicatus. Its top (the base of the Campanian Stage) is marked by the extinction of the crinoid Marsupites testudinarius. In 2009, a GSSP (official reference profile) for both base and top had not yet been appointed.
The Santonian is sometimes subdivided into Lower, Middle and Upper Substages. In the Tethys domain the Santonian is coeval with a single ammonite biozone: that of Placenticeras polyopsis. Biostratigraphy based on inoceramids, nanoplankton or forams is more detailed.
- International Commission on Stratigraphy. "ICS - Chart/Time Scale". www.stratigraphy.org.
- Lamolda, M.; Paul, C.; Peryt, D.; Pons, J. (March 2014). "The Global Boundary Stratotype and Section Point (GSSP) for the base of the Santonian Stage, "Cantera de Margas", Olazagutia, northern Spain". Episodes. 37 (1): 2–13. doi:10.18814/epiiugs/2014/v37i1/001. Retrieved 24 December 2020.
- Gradstein et al. (2004)
- "GeoWhen Database - Barremian". Archived from the original on 2007-10-22. Retrieved 2007-12-02.
- Gradstein, F.M.; Ogg, J.G. & Smith, A.G.; 2004: A Geologic Time Scale 2004, Cambridge University Press.