Santonian

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Santonian
86.3 ± 0.5 – 83.6 ± 0.2 Ma
Chronology
Etymology
Name formalityFormal
Usage information
Celestial bodyEarth
Regional usageGlobal (ICS)
Time scale(s) usedICS Time Scale
Definition
Chronological unitAge
Stratigraphic unitStage
Time span formalityFormal
Lower boundary definitionFAD of the Inoceramid Bivalve Cladoceramus undulatoplicatus
Lower boundary GSSPOlazagutia, Spain
42°52′00″N 2°11′48″W / 42.8668°N 2.1968°W / 42.8668; -2.1968
Lower GSSP ratifiedJanuary 2013[2]
Upper boundary definitionBase of Chron C33r[3]
Upper boundary GSSPBottaccione, Gubbio, Italy[3]
Coordinates Unknown
Upper GSSP ratifiedOctober 2022[4]

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.[5]

Stratigraphic definition[edit]

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.[6]

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.[6] The Santonian's top (the base of the Campanian Stage) is informally marked by the extinction of the crinoid Marsupites testudinarius.[7] A GSSP for the top of the Santonian was ratified in October 2022 in Bottaccione, Gubbio, Italy.[3]

Subdivision[edit]

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[edit]

Notes[edit]

  1. ^ International Commission on Stratigraphy. "ICS - Chart/Time Scale". www.stratigraphy.org.
  2. ^ 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.
  3. ^ 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: 1. doi:10.1016/j.cretres.2022.105415. S2CID 253436620. Retrieved 14 January 2023.
  4. ^ "Campanian GSSP Ratified by IUGS". Subcommission on Cretaceous Stratigraphy. International Commission on Stratigraphy. Retrieved 14 January 2023.
  5. ^ Gradstein et al. (2004)
  6. ^ 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.
  7. ^ 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[edit]

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

External links[edit]