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
  • 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
  • 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
  • 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
  • F. M. Gradstein, J. G. Ogg, and A. G. Smith. 2004. A Geologic Time Scale 2004 1-589 view
  • J. Meng and M. C. McKenna. 1998. Faunal turnovers of Paleogene mammals from the Mongolian Plateau. Nature 394:364-367 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 126149 collections

Show more time

Show linear time

International Chronostratigraphic TimescaleNorth American Land Mammal AgesNorth American Mammal Subages/ZonesPaleogene Mammal Ages of AsiaCenozoic Subepochs
18.5
PaleogeneOligoceneChattianArikareeanlate Late Arikareean/early Late Arikareean/late Early Arikareean/early Early ArikareeanHarrisonianTabenbulakianHsandagolianLate Oligocene23.03
Monroecreekian23.1 *
Geringian24.7 *
RupelianKekeamuanEarly Oligocene27.82
Whitneyan29.5
Orellan31.8
EocenePriabonianChadronianLate Chadronian/Middle Chadronian/Early ChadronianHouldjinian/Ergilian/UlangochuianLate Eocene33.9
Duchesnean37
BartonianSharamurunian/Irdinmanhan/ArshantanMiddle Eocene37.71
UintanLate Uintan/Early Uintan39.7
Lutetian41.2
BridgerianTwinbuttean/Blacksforkian/Gardnerbuttian46.2
YpresianBumbanianEarly Eocene47.8
WasatchianLostcabinian/Lysitean/Graybullian/Sandcouleean50.5
ClarkforkianCf3/Cf2/Cf154.9
PaleoceneThanetianGashatanLate Paleocene56
TiffanianTi6/Ti5/Ti4/Ti3/Ti2/Ti156.2
SelandianMiddle Paleocene59.2
TorrejonianTo3/To2/To160.9
DanianEarly Paleocene61.6
PuercanPu3/Pu2/Pu163.8
66