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
  • 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
  • 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

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 126849 collections

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International Chronostratigraphic TimescaleObsolete Precambrian AgesAmmonite Chrons of North AmericaCambrian of SiberiaAmmonite Chrons of Northwest EuropePermian of North AmericaSilurian of the BalticCarboniferous of North AmericaPermian of the Salt Range
PhanerozoicMesozoicJurassicMiddle JurassicBajocianEpizigzagicerasParkinsoni/Garantiana/Subfurcatum/Sauzei/Laeviuscula/Discites168.2
Rotundum/Oblatum/Kirschneri/Crassicostatus/WidebayenseHumphresianum168.4
AalenianHowelli/Scissum/WestermanniConcavum/Murchisonae/Opalinum170.9
Early JurassicToarcianYakounensis/Hillebrandti/CrassicostaLevesquei/Variabilis/BifronsThouarsense174.7
Planulata179.3 *
Arnioceras arnouldi179.8 *
180.1
Kanense181.3 *
Serpentinum/Falciferum/Tenuicostatum182
Carlottense182.3 *
Kunae183.5 *
PliensbachianSpinatum/Margaritatus/Davoei/Ibex/Jamesoni184.2
Freboldi185.1 *
Whiteavesi/ImlayiTetraspidoceras186.2 *
189.2 *
Plesechioceras harbledownense/Asteroceras varians/CoronicerasCanadensis190.3 *
SinemurianRaricostatum/Oxynotum/Obtusum/Turneri/Semicostatum/Bucklandi192.9
PseudaetomocerasPsiloceras196.4 *
Franziceras/Euphyllites196.5 *
HettangianAngulata/Liasicus/Planorbis199.5
TriassicLate TriassicRhaetian201.4
Norian208.5
Carnian227
Middle TriassicLadinian237
Anisian242
Early TriassicOlenekian247.2
Induan251.2
Kathwai251.5 *
PaleozoicPermianLopingianChanghsingian251.902
252.4 *
Chhidru252.9 *
Wuchiapingian254.14
Kalabagh255 *
Wargal256 *
GuadalupianCapitanianCapitanian259.51
WordianWordian264.28
265.3 *
Amb266.1 *
RoadianRoadian266.9
270.7 *
CisuralianKungurianLeonardianCathedralian273.01
Hessian281.9 *
Artinskian283.5
WolfcampianLenoxian286.1 *
Sakmarian290.1
AsselianNealianBursumian †293.52
CarboniferousPennsylvanianGzhelianVirgilian298.9
KasimovianMissourian303.7
Desmoinesian305.9 *
Moscovian307
Atokan312.7 *
Bashkirian315.2
Morrowan318.4 *
MississippianSerpukhovianChesterian323.2
Visean330.9
Meramecian335.8 *
Osagean343.1 *
Tournaisian346.7
Kinderhookian351.9 *
DevonianLate DevonianFamennian358.9
Frasnian372.2
Middle DevonianGivetian382.7
Eifelian387.7
Early DevonianEmsian393.3
Pragian407.6
Lochkovian410.8
SilurianPridoliOhesaare419.2
Kaugetuma421.7 *
LudlowLudfordianKuressaare423
Paadla423.4 *
Gorstian425.6
WenlockHomerianRootsikula427.4
Jaagarahu429.2 *
Sheinwoodian430.5
Jaani431.8 *
LlandoveryTelychian433.4
Adavere434 *
Aeronian438.5
Raikkula439.4 *
Rhuddanian440.8
Juuru441.4 *
OrdovicianLate OrdovicianHirnantian443.8
Katian445.2
Sandbian453
Middle OrdovicianDarriwilian458.4
Dapingian467.3
Early OrdovicianFloian470
Tremadocian477.7
Mansian †483.55 *
CambrianFurongianStage 10BatyrbaianTavgian †Ketyan †/Yurakian485.4
Jiangshanian489.5
Aksaian490.7 *
Sakian492.2 *
Paibian494
Ensyan †/Maduan/Nganasanian494.7 *
MiaolingianGuzhangianAyusokkanian497
Mayan/Menevian499.5
Drumian500.5
WuliuanAmgan/Solvan504.5
Series 2Stage 4509
ToyonianLenian †510 *
Botomian512.5 *
Stage 3514
Atdabanian515.6 *
TerreneuvianStage 2Tommotian521
Nemakit-Daldynian525.5
FortunianManykaian †529
ProterozoicNeoproterozoicEdiacaranVendian †Poundian †538.8
Wonokan †571.7 *
635