In the geologic timescale, the Valanginian is an age or stage of the Early or Lower Cretaceous. It spans between 139.8 ± 3.0 Ma and 132.9 ± 2.0 Ma (million years ago). The Valanginian Stage succeeds the Berriasian Stage of the Lower Cretaceous and precedes the Hauterivian Stage of the Lower Cretaceous.[3]

Valanginian
~139.8 – ~132.6 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 definitionNot formally defined
Lower boundary definition candidatesFAD of the Calpionellid Calpionellites darderi
Lower boundary GSSP candidate section(s)
Upper boundary definitionFAD of the Ammonite genus Acanthodiscus
Upper boundary GSSPLa Charce, Drôme, France
44°28′10″N 5°26′37″E / 44.4694°N 5.4437°E / 44.4694; 5.4437
GSSP ratifiedDecember 2019[2]

Stratigraphic definitionsEdit

The Valanginian was first described and named by Édouard Desor in 1853. It is named after Valangin, a small town north of Neuchâtel in the Jura Mountains of Switzerland.

The base of the Valanginian is at the first appearance of calpionellid species Calpionellites darderi in the stratigraphic column. A global reference section (a GSSP) had in 2009 not yet been appointed.

The top of the Valanginian (the base of the Hauterivian) is at the first appearance of the ammonite genus Acanthodiscus.

SubdivisionEdit

The Valanginian is often subdivided in Lower and Upper substages. The Upper substage begins at the first appearance of ammonite species Saynoceras verrucosum and the major marine transgression Va3.

In the Tethys domain, the Valanginian stage contains five ammonite biozones:

ReferencesEdit

NotesEdit

  1. ^ Super User. "ICS - Chart/Time Scale". www.stratigraphy.org.
  2. ^ Mutterlose, Jörg; Rawson, Peter; Reboulet, Stéphane; Baudin, François; Bulot, Luc; Emmanuel, Laurent; Gardin, Silvia; Martinez, Mathieu; Renard, Maurice (September 2020). "The Global Boundary Stratotype Section and Point (GSSP) for the base of the Hauterivian Stage (Lower Cretaceous), La Charce, southeast France". Episodes. doi:10.18814/epiiugs/2020/020072. Retrieved 24 December 2020.
  3. ^ See Gradstein et al. (2004) for a detailed geologic timescale

LiteratureEdit

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

External linksEdit