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, F. P. Agterberg, J. G. Ogg, J. Hardenbol, P. Van Veen, J. Thierry, and Z. Huang. 1995. A Triassic, Jurassic, and Cretaceous time scale. SEPM Special Publication 54 view
  • J. Palfy, P. L. Smith, and J. K. Mortensen. 2000. A U-Pb and 40Ar/39Ar time scale for the Jurassic. Canadian Journal of Earth Sciences 37(6):923-944 view
  • J. I. Raine, A. G. Beu, A. F. Boyes, H. J. Campbell, R. A. Cooper, J. S. Crampton, M. P. Crundwell, C. J. Hollis, and H. E. G. Morgans. 2015. Revised Calibration of the New Zealand Geological Timescale: NZGT2015/1. GNS Science Report 2012(39) view
  • F. F. Steininger, W. A. Berggren, D. V. Kent, R. L. Bernor, S. Sen and J. Agusti. 1996. Circum-Mediterranean Neogene (Miocene and Pliocene) marine-continental chronologic correlations of European mammal units. The Evolution of Western Eurasian Neogene Mammal Faunas (eds. R. L. Bernor, V. Fahlbusch, and H.-W. Mittmann) 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 126701 collections

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International Chronostratigraphic TimescaleOrdovician of the BalticOrdovician of AustraliaOrdovician of BritainOrdovician of Ibero-Bohemia
OrdovicianLate OrdovicianHirnantianHarjuPorkuniBolindianAshgillHirnantianKosovian443.8
KatianPirguRawtheyanKralodvorianBohdalec †445.2
Cautleyan448.9 *
Eastonian449 *
Pusgillian449.3 *
VormsiCaradocStreffordianOnnian †449.6 *
Berounian449.7 *
NabalaJohvi †450 *
ViruRakvere450.6 *
Cheneyan451.5 *
OanduGisbornian452 *
Burrellian452.7 *
SandbianKeilaIdavere †453
Actonian †453.2 *
Haljala453.9
Marshbrookian †Woolstonian †454.2 *
Longvillian †455.2 *
Zahorany †/ViniceLetna †456.2 *
Kukruse456.4 *
Aurelucian456.8 *
Soudleyan †/Harnagian/Costonian457.4 *
UhakuAluoja †457.5 *
Liben †458 *
Middle OrdovicianDarriwilianDarriwilianLlanvirnLlandeilian/Llandeilo/Late Llandeilo/Middle Llandeilo/Early Llandeilo/Late Llanvirn458.4
Dobrotivian458.5 *
Lasnamagi458.9 *
Oretanian459.7 *
Aseri460.4 *
Abereiddian/Early Llanvirn461.3 *
Sarka †461.7 *
OelandKunda462.9 *
Valaste †/Hunderum464.3 *
VolkhovLangevoja †/Vaana/Saka467.1 *
DapingianYapeenianKlabava †467.3
Arenigian468
ArenigFennian468.4 *
Castlemainian468.5 *
Billingen469.3 *
Early OrdovicianFloianChewtonian470
Latorp †470.1 *
Whitlandian471.1 *
Bendigonian471.8 *
Lancefieldian473.5 *
Hunneberg473.7 *
Moridunian474.3 *
TremadocianTremadocMigneintianTremadocian477.7
Cressagian480.8 *
Varangu481.3 *
Pakerort482.2 *
Warendian482.8 *
485 *
485.4 *
486.3
486.5