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. 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
  • F. M. Gradstein, J. G. Ogg, M. D. Schmitz and G. M. Ogg. 2020. Geologic Time Scale 2020 view
  • F. M. Gradstein, F. P. Agterberg, J. G. Ogg, J. Hardenbol, P. Van Veen, J. Thierry, and Z. Huang. 1995. A Triassic, Jurassic, and Cretaceous time scale. SEPM Special Publication 54 view
  • M. Freudenthal. 2006. Mammal Paleogene zones. personal communication 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

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 126710 collections

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International Chronostratigraphic TimescaleMammal Paleogene ZonesObsolete Names for ICS UnitsCenozoic Subepochs
2.58
PaleogeneOligoceneChattianMP 30/MP 29/MP 28/MP 27/MP 26MP 25Tertiary †Late Oligocene23.03
RupelianMP 24/MP 23/MP 22/MP 21Early Oligocene27.82
EocenePriabonianMP 20/MP 19/MP 18/MP 17B/MP 17ALate Eocene33.9
BartonianMP 16Middle Eocene37.71
LutetianMP 15/MP 14/MP 13/MP 12/MP 1141.2
YpresianMP 10/MP 8 + 9/MP 7Early Eocene47.8
PaleoceneThanetianMP 6MP 1 - 5Late Paleocene56
SelandianMiddle Paleocene59.2
DanianEarly Paleocene61.6
66