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, and A. G. Smith. 2004. A Geologic Time Scale 2004 1-589 view
  • M. O. Woodburne. 1987. A prospectus of the North American Mammal Ages. In: Woodburne, M. O. (ed.), Cenozoic Mammals of North America. University of California Press, Berkelery, CA 285-290 view
  • J. Alroy. 2000. New methods for quantifying macroevolutionary patterns and processes. Paleobiology 26(4):707-733 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
  • F. M. Gradstein, J. G. Ogg, M. D. Schmitz and G. M. Ogg. 2020. Geologic Time Scale 2020 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 126734 collections

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International Chronostratigraphic TimescaleCenozoic SubepochsNorth American Mammal Subages/ZonesNorth American Land Mammal Ages
18.5
PaleogeneOligoceneChattianLate Oligocenelate Late Arikareean/early Late Arikareean/late Early Arikareean/early Early ArikareeanHarrisonianArikareean23.03
Monroecreekian23.1 *
Geringian24.7 *
RupelianEarly Oligocene27.82
Whitneyan29.5
Orellan31.8
EocenePriabonianLate EoceneLate Chadronian/Middle Chadronian/Early ChadronianChadronian33.9
Duchesnean37
BartonianMiddle Eocene37.71
Late Uintan/Early UintanUintan39.7
Lutetian41.2
Twinbuttean/Blacksforkian/GardnerbuttianBridgerian46.2
YpresianEarly Eocene47.8
Lostcabinian/Lysitean/Graybullian/SandcouleeanWasatchian50.5
Cf3/Cf2/Cf1Clarkforkian54.9
PaleoceneThanetianLate Paleocene56
Ti6/Ti5/Ti4/Ti3/Ti2/Ti1Tiffanian56.2
SelandianMiddle Paleocene59.2
To3/To2/To1Torrejonian60.9
DanianEarly Paleocene61.6
Pu3/Pu2/Pu1Puercan63.8
66