Santonian

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.[3]

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
GSSP ratifiedJanuary 2013[2]
Upper boundary definitionNot formally defined
Upper boundary definition candidatesLAD of the Crinoid Marsupites testudinarius
Upper boundary GSSP candidate section(s)

Stratigraphic definitionEdit

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.

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.[4] In 2009, a GSSP (official reference profile) for both base and top had not yet been appointed.

SubdivisionEdit

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.

PaleontologyEdit

†AnkylosaursEdit

Ankylosaurs of the Santonian
Taxa Presence Location Description Images

Birds (avian theropods)Edit

Birds of the Santonian
Taxa Presence Location Description Images

Apatornis[6]

Neuquenornis[5]

Parahesperornis[6]

Patagopteryx[5]

Cartilaginous FishEdit

Cartilaginous Fish of the Santonian
Taxa Presence Location Description Images

†CeratopsiansEdit

Ceratopsians of the Santonian
Taxa Presence Location Description Images

CrocodylomorphsEdit

Crocodylomorphs of the Santonian
Taxa Presence Location Description Images
Mid-Late Santonian Bajo de la Carpa Formation, Patagonia, Argentina
 
Reconstruction of Comahuesuchus
 
Reconstruction of Notosuchus
Csehbánya Formation, Bakony Mountains, Hungary
Mid-Late Santonian Bajo de la Carpa Formation, Patagonia, Argentina
Santonian-Campanian Gobi desert, Mongolia

MammalsEdit

Mammals of the Santonian
Taxa Presence Location Description Images
  • Paracimexomys
  1. Paracimexomys magister[5]

†OrnithopodsEdit

Ornithopods of the Santonian
Taxa Presence Location Description Images

†PlesiosaursEdit

Plesiosauria of the Santonian
Taxa Presence Location Description Images
Dolichorhynchops osborni from Coniacian to Campanian Fort Hays Limestone, Kansas, USA
 
Reconstruction of Dolichorhynchops

†PterosaursEdit

Pterosaurs of the Santonian
Taxa Presence Location Description Images
 
Reconstruction of Bakonydraco

†SauropodsEdit

Sauropods of the Santonian
Taxa Presence Location Description Images
Santonian-Campanian Bajo de la Carpa Formation, Argentina

SquamatesEdit

Squamates of the Santonian
Taxa Presence Location Description Images

Eonatator

 
Reconstruction of Tylosaurus, a mosasaur
  1. Madtsoia madagascariensis[6]

Pannoniasaurus

Tylosaurus

†Theropods (non-avian)Edit

Non-avian theropods of the Santonian
Taxa Presence Location Description Images

Achillesaurus[5]

Achillobator

Alectrosaurus

Aucasaurus[5]

Erlikosaurus

Gigantoraptor

Thanos

Xixiasaurus

FloraEdit

ReferencesEdit

NotesEdit

  1. ^ Super User. "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. ^ Gradstein et al. (2004)
  4. ^ "GeoWhen Database - Barremian". Archived from the original on 2007-10-22. Retrieved 2007-12-02. Version 1.1.0.
  5. ^ a b c d e f g Only known from this stage
  6. ^ a b c d Dating uncertain

LiteratureEdit

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

External linksEdit