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
  • F. M. Gradstein, J. G. Ogg, M. D. Schmitz and G. M. Ogg. 2020. Geologic Time Scale 2020 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, 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 126864 collections

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International Chronostratigraphic TimescaleCambrian of BritainDevonian SubagesSilurian of the BalticCarboniferous of ChinaPermian of the Russian PlatformPermian of North AmericaAmmonite Chrons of Northwest EuropeCarboniferous of Western EuropeCambrian of North America
JurassicMiddle JurassicBajocianParkinsoni/Garantiana/Subfurcatum/Sauzei/Laeviuscula/Discites168.2
Humphresianum168.4
AalenianConcavum/Murchisonae/Opalinum170.9
Early JurassicToarcianLevesquei/Variabilis/BifronsThouarsense174.7
180.1
Serpentinum/Falciferum/Tenuicostatum182
PliensbachianSpinatum/Margaritatus/Davoei/Ibex/Jamesoni184.2
SinemurianRaricostatum/Oxynotum/Obtusum/Turneri/Semicostatum/Bucklandi192.9
HettangianAngulata/Liasicus/Planorbis199.5
TriassicLate TriassicRhaetian201.4
Norian208.5
Carnian227
Middle TriassicLadinian237
Anisian242
Early TriassicOlenekian247.2
Induan251.2
PermianLopingianChanghsingian251.902
Wuchiapingian254.14
TatarianVyatkian256.8 *
GuadalupianCapitanianSeverodvinianCapitanian259.51
WordianUrzhumianWordian264.28
RoadianKazanianPovolzhianRoadian266.9
Sokian270.7 *
CisuralianKungurianKungurianIrenian/UfimianLeonardianCathedralian273.01
Filipovian276.5 *
Saraninian280.1 *
Hessian281.9 *
ArtinskianArtinskianSarginian283.5
Irginian285.9 *
WolfcampianLenoxian286.1 *
Burtsevian287.8 *
SakmarianSakmarianSterlitamakian290.1
Tastubian291.7 *
AsselianAsselianShikhanianNealian293.52
Uskalykian294.8
Surenian297.5
Kuzel297.7
CarboniferousPennsylvanianGzhelian298.9
Xiaodushanian300 *
StephanianStephanian C300.3 *
Stephanian B300.9 *
Stephanian A301.4 *
Kasimovian303.7
Cantabrian305 *
Dalaun305.8 *
Moscovian307
WestphalianWestphalian D307.4 *
Westphalian C309.8
Westphalian B314.6
Bashkirian315.2
Westphalian A317 *
Huashibanian318.5 *
NamurianYeadonian318.8 *
Marsdenian320.2 *
Lousuan321.2 *
Kinderscoutian321.5 *
Alportian322 *
Chokierian323.1 *
MississippianSerpukhovianDewunian323.2
Arnsbergian324 *
Pendleian327.4 *
Shangsian330.8 *
ViseanWarnantianBrigantian †330.9
Jiusian335 *
LivianAsbian †336.3 *
MoliniacianHolkerian †/Arundian/Chadian340.2 *
TournaisianTangbagouanIvorian346.7
Hastarian353.7 *
DevonianLate DevonianFamennianLate Famennian358.9
Middle Famennian365.3 *
Early Famennian368.5 *
FrasnianLate Frasnian372.2
Middle Frasnian375.4 *
Early Frasnian379.3 *
Middle DevonianGivetianLate Givetian382.7
Middle Givetian383.7 *
Early Givetian385.9 *
EifelianLate Eifelian387.7
Early Eifelian390.3 *
Early DevonianEmsianLate Emsian393.3
Early Emsian398.3 *
PragianPragian407.6
LochkovianLate Lochkovian410.8
Middle Lochkovian412.8 *
Early Lochkovian415.6 *
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
CambrianFurongianStage 10MerionethDolgellian/TrempealeauanFranconian †/Dresbachian/Millardan485.4
Sunwaptan487.5
Festiniogian489.2 *
Jiangshanian489.5
Steptoean493 *
Maentwrogian493.1 *
Paibian494
MiaolingianGuzhangianSt DavidsMarjumianAlbertian †497
Drumian500.5
WuliuanTopazan504.5
Delamaran506.5
Series 2Stage 4CaerfaiWaucoban †509
Dyeran511 *
Stage 3514
Montezuman514.8 *
Begadean519.9 *
TerreneuvianStage 2521
Fortunian529
538.8