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
  • A. D. Barnosky, M. Holmes, R. Kirchholtes, E. Lindsey, K.C. Maguire, A.W. Poust, M.A. Stegner, J. Sunseri, B. Swartz, J. Swift, N.A. Villavicencio and G. Wogan. 2014. Prelude to the Anthropocene: Two new North American Land Mammal Ages (NALMAs). The Anthropocene Review I(3):225-242 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 126610 collections

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International Chronostratigraphic TimescaleObsolete Names for ICS UnitsNorth American Land Mammal Ages
2.58
18.5
PaleogeneOligoceneChattianTertiary †Arikareean23.03
Rupelian27.82
Whitneyan29.5
Orellan31.8
EocenePriabonianChadronian33.9
Duchesnean37
Bartonian37.71
Uintan39.7
Lutetian41.2
Bridgerian46.2
Ypresian47.8
Wasatchian50.5
Clarkforkian54.9
PaleoceneThanetian56
Tiffanian56.2
Selandian59.2
Torrejonian60.9
Danian61.6
Puercan63.8
66