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, 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
  • F. M. Gradstein, J. G. Ogg, and A. G. Smith. 2004. A Geologic Time Scale 2004 1-589 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 127456 collections

Show more time

Show linear time

International Chronostratigraphic TimescaleCambrian of North AmericaCarboniferous SubepochsOrdovician of the BalticObsolete Carboniferous Ages of ChinaOrdovician of AustraliaCambrian of BritainPermian of the PamirsObsolete Precambrian AgesCambrian of ChinaPrecambrian of Russia
PhanerozoicPaleozoicPermianLopingianChanghsingianDorashamian251.902
WuchiapingianDzhulfian254.14
GuadalupianCapitanianMidian259.51
Wordian264.28
Murgabian266.2 *
Roadian266.9
CisuralianKungurianKubergandian273.01
Bolorian279.8
Artinskian283.5
Yakhtashian286
SakmarianSakmarian290.1
AsselianAsselian293.52
CarboniferousPennsylvanianGzhelianLate PennsylvanianMapingian †298.9
Kasimovian303.7
305.9
MoscovianMiddle Pennsylvanian307
BashkirianEarly Pennsylvanian315.2
MississippianSerpukhovianLate Mississippian323.2
ViseanMiddle Mississippian330.9
TournaisianEarly Mississippian346.7
DevonianLate DevonianFamennian358.9
Frasnian372.2
Middle DevonianGivetian382.7
Eifelian387.7
Early DevonianEmsian393.3
Pragian407.6
Lochkovian410.8
SilurianPridoli419.2
LudlowLudfordian423
Gorstian425.6
WenlockHomerian427.4
Sheinwoodian430.5
LlandoveryTelychian433.4
Aeronian438.5
Rhuddanian440.8
OrdovicianLate OrdovicianHirnantianHarjuPorkuniBolindian443.8
KatianPirgu445.2
Eastonian449 *
Vormsi449.6 *
NabalaJohvi †450 *
ViruRakvere450.6 *
OanduGisbornian452 *
SandbianKeilaIdavere †453
Haljala453.9
Kukruse456.4 *
UhakuAluoja †457.5 *
Middle OrdovicianDarriwilianDarriwilian458.4
Lasnamagi458.9 *
Aseri460.4 *
OelandKunda462.9 *
Valaste †/Hunderum464.3 *
VolkhovLangevoja †/Vaana/Saka467.1 *
DapingianYapeenian467.3
Castlemainian468.5 *
Billingen469.3 *
Early OrdovicianFloianChewtonian470
Latorp †470.1 *
Bendigonian471.8 *
Lancefieldian473.5 *
Hunneberg473.7 *
Tremadocian477.7
Varangu481.3 *
Pakerort482.2 *
Warendian482.8 *
CambrianFurongianStage 10Franconian †/Dresbachian/MillardanMerionethDolgellian/TrempealeauanNiucheheanTaoyuanian †485.4
486.3 *
486.5
Sunwaptan487.5
Festiniogian489.2 *
JiangshanianJiangshanian489.5
Steptoean493 *
Maentwrogian493.1 *
PaibianPaibian494
Waergangian †/Youshuanian494.9 *
MiaolingianGuzhangianMarjumianAlbertian †St DavidsGuzhangianWangcunian †497
DrumianDrumian500.5
WuliuanTopazanWuliuan/Taijangian504.5
Delamaran506.5
Series 2Stage 4Waucoban †CaerfaiDuyunian509
Dyeran511 *
Stage 3Nangaoian514
Montezuman514.8 *
Begadean519.9 *
TerreneuvianStage 2Meishucunian521
Fortunian529
Jinnigian530.7
ProterozoicNeoproterozoicEdiacaranVendian †Poundian †Vendian538.8
Wonokan †571.7 *
Cryogenian635
Tonian720
Karatau800
MesoproterozoicStenian1000
Yurmatian1100
Ectasian1200
Burzyan1375
1400