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
  • 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
  • F. M. Gradstein, J. G. Ogg, M. D. Schmitz and G. M. Ogg. 2020. Geologic Time Scale 2020 view
  • F. M. Gradstein, J. G. Ogg, and A. G. Smith. 2004. A Geologic Time Scale 2004 1-589 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
  • D. H. Erwin and S. A. Bowring. 2004. Cambrian time scale. 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 126778 collections

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International Chronostratigraphic TimescaleObsolete Names for ICS UnitsCambrian of KazakhstanCambrian of North AmericaTen Million Year BinsCambrian of Siberia
CambrianFurongianStage 10BatyrbaianFranconian †/Dresbachian/MillardanCambrian 5BatyrbaianTavgian †Ketyan †/Yurakian485.4
Sunwaptan487.5
Jiangshanian489.5
AksaianAksaian490.7 *
SakianSakian492.2 *
Steptoean493 *
Paibian494
Ensyan †/Maduan/Nganasanian494.7 *
MiaolingianGuzhangianSeries 3 †AyusokkanianMarjumianAlbertian †Cambrian 4Ayusokkanian497
Mayan/Menevian499.5
DrumianZhanaarykian500.5
Tuesaian503
WuliuanStage 5 †TopazanCambrian 3Amgan/Solvan504.5
505.3
Delamaran506.5
Series 2Stage 4Waucoban †509
ToyonianToyonianLenian †510 *
Dyeran511 *
BotomianBotomian512.5 *
Stage 3Cambrian 2514
Montezuman514.8 *
AtdabanianAtdabanian515.6 *
Begadean519.9 *
TerreneuvianStage 2TommotianTommotian521
Nemakit-Daldynian525.5
FortunianCambrian 1Manykaian †529
538.8