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
  • F. M. Gradstein, J. G. Ogg, and A. G. Smith. 2004. A Geologic Time Scale 2004 1-589 view
  • F. M. Gradstein, J. G. Ogg, M. D. Schmitz and G. M. Ogg. 2020. Geologic Time Scale 2020 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

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 126864 collections

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International Chronostratigraphic TimescaleCarboniferous of North AmericaPermian of ChinaDevonian of GermanyDevonian of CzechoslovakiaAmmonite Chrons of North AmericaSilurian of North AmericaSilurian of the Baltic
JurassicMiddle JurassicBajocianEpizigzagiceras168.2
Rotundum/Oblatum/Kirschneri/Crassicostatus/Widebayense168.4
AalenianHowelli/Scissum/Westermanni170.9
Early JurassicToarcianYakounensis/Hillebrandti/Crassicosta174.7
Planulata179.3 *
Arnioceras arnouldi179.8 *
Kanense181.3 *
Carlottense182.3 *
Kunae183.5 *
Pliensbachian184.2
Freboldi185.1 *
Whiteavesi/ImlayiTetraspidoceras186.2 *
189.2 *
Plesechioceras harbledownense/Asteroceras varians/CoronicerasCanadensis190.3 *
Sinemurian192.9
PseudaetomocerasPsiloceras196.4 *
Franziceras/Euphyllites196.5 *
Hettangian199.5
TriassicLate TriassicRhaetian201.4
Norian208.5
Carnian227
Middle TriassicLadinian237
Anisian242
Early TriassicOlenekian247.2
Induan251.2
PermianLopingianChanghsingianMeishanian251.902
Baoqingian253.4 *
WuchiapingianLaoshanian254.14
Laibinian257.7 *
GuadalupianCapitanianLengwuan259.51
WordianKuhfengian264.28
Roadian266.9
CisuralianKungurianLuodianian273.01
Artinskian283.5
Longlinian285.4 *
Sakmarian290.1
AsselianBursumian †Zisongian293.52
CarboniferousPennsylvanianGzhelianVirgilian298.9
300.1
KasimovianMissourian303.7
Desmoinesian305.9 *
Moscovian307
Atokan312.7 *
Bashkirian315.2
Morrowan318.4 *
MississippianSerpukhovianChesterian323.2
Visean330.9
Meramecian335.8 *
Osagean343.1 *
Tournaisian346.7
Kinderhookian351.9 *
DevonianLate DevonianFamennianWocklum/Dasberg/Hemberg/Nehden358.9
FrasnianAdorf372.2
Middle DevonianGivetianGivetianSrbsko382.7
EifelianEifelianChotec387.7
Early DevonianEmsianEmsianDaleje/Zlichovian393.3
PragianSiegenPragian407.6
LochkovianGedinnineLochkovian410.8
SilurianPridoliCayuganOhesaare419.2
Kaugetuma421.7 *
Niagaran422.5 *
LudlowLudfordianKuressaare423
Paadla423.4 *
Gorstian425.6
WenlockHomerianLockportianRootsikula427.4
Jaagarahu429.2 *
Sheinwoodian430.5
Jaani431.8 *
LlandoveryTelychianOntarian433.4
Adavere434 *
Aeronian438.5
Alexandrian438.7 *
Raikkula439.4 *
MedinanClinton440.1 *
440.7 *
Rhuddanian440.8
Juuru441.4 *
443.8