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
  • B. D. Webby. 1998. Steps toward a global standard for Ordovician stratigraphy. Newsletters in Stratigraphy 36:1-33 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 126831 collections

Show more time

Show linear time

International Chronostratigraphic TimescaleObsolete Carboniferous Ages of ChinaOrdovician of AustraliaCarboniferous of North AmericaCarbo-Permian of the Russian PlatformSilurian Ages of EuropeCarboniferous SubepochsOrdovician of Britain
PermianLopingianChanghsingianMelekhovian251.902
Wuchiapingian254.14
GuadalupianCapitanian259.51
Wordian264.28
Noginskian264.9 *
Roadian266.9
CisuralianKungurian273.01
Pavlovoposadian276.8 *
Artinskian283.5
Rusavkinian287.6 *
Sakmarian290.1
AsselianBursumian †293.52
CarboniferousPennsylvanianGzhelianMapingian †VirgilianLate Pennsylvanian298.9
KasimovianMissourianDorogomilovian303.7
Khamovnikian304.8
Krevyakinian305.8 *
Desmoinesian305.9 *
MoscovianMyachkovianMiddle Pennsylvanian307
Podolskian308.9 *
Kashirian311.4 *
Atokan312.7 *
Vereian313.8
Melekessian314.8
BashkirianEarly Pennsylvanian315.2
Cheremshanian316.9 *
Morrowan318.4 *
Prikamian318.6 *
Severokeltmian319.9 *
Krasnopolyanian321.2 *
Voznesenian321.9 *
MississippianSerpukhovianChesterianZapaltjubianLate Mississippian323.2
Protvian324.4 *
Steshevian326.8 *
Tarusian329 *
ViseanVenevianMiddle Mississippian330.9
Mikhailovian331.9 *
Aleksinian333.7 *
MeramecianTulian335.8 *
Bobrikian339.9 *
Osagean343.1 *
Radaevkian343.4 *
TournaisianKosvianEarly Mississippian346.7
Kizelian350.7 *
KinderhookianCherepetian351.9 *
Karakubian354.4 *
Upinian356.3 *
Malevkian357.6 *
Gumerovian358 *
DevonianLate DevonianFamennian358.9
Frasnian372.2
Middle DevonianGivetian382.7
Eifelian387.7
Early DevonianEmsian393.3
Pragian407.6
Lochkovian410.8
SilurianPridoli419.2
LudlowLudfordian423
Gorstian425.6
WenlockHomerianGleedonian427.4
Whitwellian429.7 *
Sheinwoodian430.5
LlandoveryTelychian433.4
Aeronian438.5
Rhuddanian440.8
OrdovicianLate OrdovicianHirnantianBolindianAshgillHirnantian443.8
KatianRawtheyan445.2
Cautleyan448.9 *
Eastonian449 *
Pusgillian449.3 *
CaradocStreffordianOnnian †449.6 *
Cheneyan451.5 *
Gisbornian452 *
Burrellian452.7 *
Sandbian453
Actonian †453.2 *
Marshbrookian †Woolstonian †454.2 *
Longvillian †455.2 *
Aurelucian456.8 *
Soudleyan †/Harnagian/Costonian457.4 *
Middle OrdovicianDarriwilianDarriwilianLlanvirnLlandeilian/Llandeilo/Late Llandeilo/Middle Llandeilo/Early Llandeilo/Late Llanvirn458.4
Abereiddian/Early Llanvirn461.3 *
DapingianYapeenian467.3
ArenigFennian468.4 *
Castlemainian468.5 *
Early OrdovicianFloianChewtonian470
Whitlandian471.1 *
Bendigonian471.8 *
Lancefieldian473.5 *
Moridunian474.3 *
TremadocianTremadocMigneintian477.7
Cressagian480.8 *
Warendian482.8 *
485 *
485.4