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, and A. G. Smith. 2004. A Geologic Time Scale 2004 1-589 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
  • A. G. Sennikov and V. K. Golubev. 2006. Vyazniki Biotic Assemblage of the Terminal Permian. Paleontological Journal 40(suppl. 4):S475-S481 view
  • F. M. Gradstein, J. G. Ogg, M. D. Schmitz and G. M. Ogg. 2020. Geologic Time Scale 2020 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 TimescaleTen Million Year BinsOrdovician of AustraliaOrdovician of the Baltic
OrdovicianLate OrdovicianHirnantianOrdovician 5BolindianHarjuPorkuni443.8
KatianPirgu445.2
Eastonian449 *
Vormsi449.6 *
NabalaJohvi †450 *
ViruRakvere450.6 *
GisbornianOandu452 *
SandbianOrdovician 4KeilaIdavere †453
Haljala453.9
Kukruse456.4 *
UhakuAluoja †457.5 *
Middle OrdovicianDarriwilianOrdovician 3Darriwilian458.4
Lasnamagi458.9 *
Aseri460.4 *
OelandKunda462.9 *
Valaste †/Hunderum464.3 *
VolkhovLangevoja †/Vaana/Saka467.1 *
DapingianOrdovician 2Yapeenian467.3
Castlemainian468.5 *
Billingen469.3 *
Early OrdovicianFloianChewtonian470
Latorp †470.1 *
Bendigonian471.8 *
Lancefieldian473.5 *
Hunneberg473.7 *
TremadocianOrdovician 1477.7
Varangu481.3 *
Pakerort482.2 *
Warendian482.8 *
485.4 *
486.3
486.5