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Santonian
Santonian
86.3 ± 0.5 – 83.6 ± 0.2 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
Chronology
←	K-Pg mass; extinction
	Subdivision of the Cretaceous according to the ICS, as of 2023.; Vertical axis scale: Millions of years ago
Etymology
Name formality	Formal
Usage information
Celestial body	Earth
Regional usage	Global (ICS)
Time scale(s) used	ICS Time Scale
Definition
Chronological unit	Age
Stratigraphic unit	Stage
Time span formality	Formal
Lower boundary definition	FAD of the Inoceramid Bivalve Cladoceramus undulatoplicatus
Lower boundary GSSP	Olazagutia, Spain; 42°52′00″N 2°11′48″W / 42.8668°N 2.1968°W
Lower GSSP ratified	January 2013
Upper boundary definition	Base of Chron C33r
Upper boundary GSSP	Bottaccione, Gubbio, Italy; 43°21′46″N 12°34′58″E / 43.3627°N 12.5828°E
Upper GSSP ratified	October 2022

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.^[6]

Stratigraphic definition

The Santonian Stage was established by French geologist Henri Coquand in 1857. It is named after the city of Saintes in the region of Saintonge, where the original type locality is located.^[7]

The base of the Santonian Stage is defined by the appearance of the inoceramid bivalve Cladoceramus undulatoplicatus. The GSSP (official reference profile) for the base of the Santonian Stage is located near Olazagutia, Spain; it was ratified by the Subcommission on Cretaceous Stratigraphy in 2012.^[7] The Santonian's top (the base of the Campanian Stage) is informally marked by the extinction of the crinoid Marsupites testudinarius.^[8] A GSSP for the top of the Santonian was ratified in October 2022 in Bottaccione, Gubbio, Italy.^[3]

Subdivision

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.

References

Notes

^ "International Chronostratigraphic Chart" (PDF). International Commission on Stratigraphy. September 2023. Retrieved December 16, 2024.
^ 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.
^ ^a ^b ^c Jarvis, Ian; et al. (2023). "Carbon isotopes, palynology and stratigraphy of the Santonian–Campanian boundary: The GSSP auxiliary sections, Seaford Head (England) and Bocieniec (Poland), and correlation between the Boreal and Tethyan realms". Cretaceous Research. 143: 105415. Bibcode:2023CrRes.14305415J. doi:10.1016/j.cretres.2022.105415. hdl:10871/133015. S2CID 253436620.
^ Gale, Andy; Batenburg, Sietske; Coccioni, Rodolfo; Dubicka, Zofia; Erba, Elisabetta; Falzoni, Francesca; Haggart, Jim; Hasegawa, Takishi; Ifrim, Christina; Jarvis, Ian; Jenkyns, Hugh; Jurowska, Agata; Kennedy, Jim; Maron, Matteo; Muttoni, Giovanni; Pearce, Martin; Petrizzo, Maria Rose; Premoli-Silva, Isabella; Thibault, Nicolas; Voigt, Silke; Wagreich, Michael; Walaszczyk, Irek (1 February 2023). "The Global Boundary Stratotype Section and Point (GSSP) of the Campanian Stage at Bottaccione (Gubbio, Italy) and its Auxiliary Sections: Seaford Head (UK), Bocieniec (Poland), Postalm (Austria), Smoky Hill, Kansas (U.S.A), Tepayac (Mexico)". Episodes. 46 (3): 6. doi:10.18814/epiiugs/2022/022048. hdl:2434/968946. S2CID 256539746. Retrieved 27 March 2023.
^ "Campanian GSSP Ratified by IUGS". Subcommission on Cretaceous Stratigraphy. International Commission on Stratigraphy. Retrieved 14 January 2023.
^ Gradstein et al. (2004)
^ ^a ^b Gradstein, F.M.; Ogg, J.G.; Schmitz, M.D.; Ogg, G.M., eds. (2020). Geologic Time Scale 2020. Elsevier. p. 1038. ISBN 978-0-12-824360-2.
^ Gradstein, F.M.; Ogg, J.G.; Schmitz, M.D.; Ogg, G.M., eds. (2020). Geologic Time Scale 2020. Elsevier. p. 1040. ISBN 978-0-12-824360-2.

Literature

Gradstein, F.M.; Ogg, J.G. & Smith, A.G.; 2004: A Geologic Time Scale 2004, Cambridge University Press.

External links

GeoWhen Database - Santonian
Late Cretaceous timescale, at the website of the subcommission for stratigraphic information of the ICS
Stratigraphic chart of the Late Cretaceous, at the website of Norges Network of offshore records of geology and stratigraphy