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
  • 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
  • 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
  • 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. 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
  • 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 127258 collections

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International Chronostratigraphic TimescaleNorth American Mammal Subages/ZonesNorth American Land Mammal Ages
18.5
PaleogeneOligoceneChattianlate Late Arikareean/early Late Arikareean/late Early Arikareean/early Early ArikareeanHarrisonianArikareean23.03
Monroecreekian23.1 *
Geringian24.7 *
Rupelian27.82
Whitneyan29.5
Orellan31.8
EocenePriabonianLate Chadronian/Middle Chadronian/Early ChadronianChadronian33.9
Duchesnean37
Bartonian37.71
Late Uintan/Early UintanUintan39.7
Lutetian41.2
Twinbuttean/Blacksforkian/GardnerbuttianBridgerian46.2
Ypresian47.8
Lostcabinian/Lysitean/Graybullian/SandcouleeanWasatchian50.5
Cf3/Cf2/Cf1Clarkforkian54.9
PaleoceneThanetian56
Ti6/Ti5/Ti4/Ti3/Ti2/Ti1Tiffanian56.2
Selandian59.2
To3/To2/To1Torrejonian60.9
Danian61.6
Pu3/Pu2/Pu1Puercan63.8
66