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
  • J. A. Lillegraven and M. C. McKenna. 1986. Fossil mammals from the "Mesaverde" Formation (Late Cretaceous, Judithian) of the Bighorn and Wind River basins, Wyoming, with definitions of Late Cretaceous North American Land-Mammal "Ages". American Museum Novitates 2840:1-68 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
  • B. D. Webby. 1998. Steps toward a global standard for Ordovician stratigraphy. Newsletters in Stratigraphy 36:1-33 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

Show more time

Show linear time

International Chronostratigraphic TimescaleOrdovician of Ibero-BohemiaOrdovician of the Baltic
OrdovicianLate OrdovicianHirnantianKosovianHarjuPorkuni443.8
KatianKralodvorianBohdalec †Pirgu445.2
Vormsi449.6 *
Berounian449.7 *
NabalaJohvi †450 *
ViruRakvere450.6 *
Oandu452 *
SandbianKeilaIdavere †453
Haljala453.9
Zahorany †/ViniceLetna †456.2 *
Kukruse456.4 *
UhakuAluoja †457.5 *
Liben †458 *
Middle OrdovicianDarriwilian458.4
Dobrotivian458.5 *
Lasnamagi458.9 *
Oretanian459.7 *
Aseri460.4 *
Sarka †461.7 *
OelandKunda462.9 *
Valaste †/Hunderum464.3 *
VolkhovLangevoja †/Vaana/Saka467.1 *
DapingianKlabava †467.3
Arenigian468
Billingen469.3 *
Early OrdovicianFloian470
Latorp †470.1 *
Hunneberg473.7 *
TremadocianTremadocian477.7
Varangu481.3 *
Pakerort482.2 *
485.4 *
486.3
486.5