International Chronostratigraphic Timescale

The interval definitions in this timescale are derived from the following sources:

  • K. M. Cohen, S.C. Finney, P.L. Gibbard and J.-X. Fan. 2023. The ICS International Chronostratigraphic Chart v2023/09. view
  • F. M. Gradstein, J. G. Ogg, M. D. Schmitz and G. M. Ogg. 2020. Geologic Time Scale 2020 view
  • W. B. Harland, R. L. Armstrong, A. V. Cox, L. E. Craig, A. G. Smith and D. G. Smith. 1990. A Geologic Time Scale 1989. view
  • B. D. Webby. 1998. Steps toward a global standard for Ordovician stratigraphy. Newsletters in Stratigraphy 36:1-33 view
  • F. M. Gradstein, J. G. Ogg, and A. G. Smith. 2004. A Geologic Time Scale 2004 1-589 view
  • J. Meng and M. C. McKenna. 1998. Faunal turnovers of Paleogene mammals from the Mongolian Plateau. Nature 394:364-367 view
  • P. L. Gibbard, M. J. Head, and M. J. C. Walker. 2010. Formal ratification of the Quaternary System/Period and the Pleistocene Series/Epoch with a base at 2.58 Ma. Journal of Quaternary Science 25(2):96-102 view

There are 59 timescales which overlap this one. show

Interval boundaries marked with * have been interpolated based on the differences between the ages for international timescale boundaries quoted in the source and the currently accepted ages for those boundaries.

Interval names marked with † are no longer in current use.

This timescale is used in the definition of 126585 collections

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International Chronostratigraphic TimescaleOrdovician of BritainTen Million Year BinsOrdovician of Ibero-Bohemia
OrdovicianLate OrdovicianHirnantianAshgillHirnantianOrdovician 5Kosovian443.8
KatianRawtheyanKralodvorianBohdalec †445.2
Cautleyan448.9 *
Pusgillian449.3 *
CaradocStreffordianOnnian †449.6 *
Berounian449.7 *
Cheneyan451.5 *
Burrellian452.7 *
SandbianOrdovician 4453
Actonian †453.2 *
Marshbrookian †Woolstonian †454.2 *
Longvillian †455.2 *
Zahorany †/ViniceLetna †456.2 *
Aurelucian456.8 *
Soudleyan †/Harnagian/Costonian457.4 *
Liben †458 *
Middle OrdovicianDarriwilianLlanvirnLlandeilian/Llandeilo/Late Llandeilo/Middle Llandeilo/Early Llandeilo/Late LlanvirnOrdovician 3458.4
Dobrotivian458.5 *
Oretanian459.7 *
Abereiddian/Early Llanvirn461.3 *
Sarka †461.7 *
DapingianOrdovician 2Klabava †467.3
Arenigian468
ArenigFennian468.4 *
Early OrdovicianFloian470
Whitlandian471.1 *
Moridunian474.3 *
TremadocianTremadocMigneintianOrdovician 1Tremadocian477.7
Cressagian480.8 *
485 *
485.4