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
  • B. D. Webby. 1998. Steps toward a global standard for Ordovician stratigraphy. Newsletters in Stratigraphy 36:1-33 view
  • M. Freudenthal. 2006. Mammal Paleogene zones. personal communication 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 127017 collections

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International Chronostratigraphic TimescaleTen Million Year BinsObsolete Precambrian AgesOrdovician of BritainCretaceous SubepochsPermian of the PamirsMammal Paleogene ZonesObsolete Names for ICS UnitsAmmonite Chrons of Northwest EuropeDevonian of Germany
PhanerozoicCenozoicQuaternaryHoloceneMeghalayanCenozoic 60
Northgrippian0.0042
Greenlandian0.0082
PleistoceneLate Pleistocene0.0117
Chibanian0.129
Calabrian0.774
Gelasian1.8
NeogenePliocenePiacenzianTertiary †2.58
Zanclean3.6
MioceneMessinian5.333
Tortonian7.246
SerravallianCenozoic 511.63
Langhian13.82
Burdigalian15.98
Aquitanian20.44
PaleogeneOligoceneChattianCenozoic 4MP 30/MP 29/MP 28/MP 27/MP 26MP 2523.03
RupelianMP 24/MP 23/MP 22/MP 2127.82
EocenePriabonianCenozoic 3MP 20/MP 19/MP 18/MP 17B/MP 17A33.9
BartonianMP 1637.71
LutetianCenozoic 2MP 15/MP 14/MP 13/MP 12/MP 1141.2
YpresianMP 10/MP 8 + 9/MP 747.8
PaleoceneThanetianCenozoic 1MP 6MP 1 - 556
Selandian59.2
Danian61.6
MesozoicCretaceousLate CretaceousMaastrichtianCretaceous 8Senonian66
CampanianCretaceous 772.1
SantonianCretaceous 683.6
Coniacian86.3
Turonian89.8
CenomanianCretaceous 593.9
Early CretaceousAlbianCretaceous 4Gallic100.5
AptianCretaceous 3113
BarremianCretaceous 2121.4
HauterivianNeocomian125.77
ValanginianCretaceous 1132.6
Berriasian139.8
JurassicLate JurassicTithonianJurassic 6145
KimmeridgianJurassic 5149.2
Oxfordian154.8
Middle JurassicCallovian161.5
BathonianJurassic 4165.3
BajocianParkinsoni/Garantiana/Subfurcatum/Sauzei/Laeviuscula/Discites168.2
Humphresianum168.4
AalenianJurassic 3Concavum/Murchisonae/Opalinum170.9
Early JurassicToarcianLevesquei/Variabilis/BifronsThouarsense174.7
180.1
Serpentinum/Falciferum/Tenuicostatum182
PliensbachianJurassic 2Spinatum/Margaritatus/Davoei/Ibex/Jamesoni184.2
SinemurianJurassic 1Raricostatum/Oxynotum/Obtusum/Turneri/Semicostatum/Bucklandi192.9
HettangianAngulata/Liasicus/Planorbis199.5
TriassicLate TriassicRhaetianTriassic 4201.4
Norian208.5
CarnianTriassic 3227
Middle TriassicLadinianTriassic 2237
Anisian242
Early TriassicOlenekianTriassic 1247.2
Induan251.2
PaleozoicPermianLopingianChanghsingianPermian 4Dorashamian251.902
WuchiapingianDzhulfianLongtanian †254.14
GuadalupianCapitanianMidian259.51
Wordian264.28
Murgabian266.2 *
RoadianPermian 3266.9
CisuralianKungurianPermian 2Kubergandian273.01
Bolorian279.8
Artinskian283.5
Yakhtashian286
SakmarianSakmarian290.1
AsselianPermian 1Asselian293.52
CarboniferousPennsylvanianGzhelianCarboniferous 5298.9
Kasimovian303.7
MoscovianCarboniferous 4307
Bashkirian315.2
MississippianSerpukhovianCarboniferous 3323.2
ViseanCarboniferous 2330.9
TournaisianCarboniferous 1346.7
DevonianLate DevonianFamennianDevonian 5Wocklum/Dasberg/Hemberg/Nehden358.9
FrasnianDevonian 4Adorf372.2
Middle DevonianGivetianDevonian 3Givetian382.7
EifelianEifelian387.7
Early DevonianEmsianDevonian 2Emsian393.3
PragianDevonian 1Siegen407.6
LochkovianGedinnine410.8
SilurianPridoliSilurian 2419.2
LudlowLudfordian423
Gorstian425.6
WenlockHomerian427.4
Sheinwoodian430.5
LlandoveryTelychianSilurian 1433.4
Aeronian438.5
Rhuddanian440.8
OrdovicianLate OrdovicianHirnantianOrdovician 5AshgillHirnantian443.8
KatianRawtheyan445.2
Cautleyan448.9 *
Pusgillian449.3 *
CaradocStreffordianOnnian †449.6 *
Cheneyan451.5 *
Burrellian452.7 *
SandbianOrdovician 4453
Actonian †453.2 *
Marshbrookian †Woolstonian †454.2 *
Longvillian †455.2 *
Aurelucian456.8 *
Soudleyan †/Harnagian/Costonian457.4 *
Middle OrdovicianDarriwilianOrdovician 3LlanvirnLlandeilian/Llandeilo/Late Llandeilo/Middle Llandeilo/Early Llandeilo/Late Llanvirn458.4
Abereiddian/Early Llanvirn461.3 *
DapingianOrdovician 2467.3
ArenigFennian468.4 *
Early OrdovicianFloian470
Whitlandian471.1 *
Moridunian474.3 *
TremadocianOrdovician 1TremadocMigneintian477.7
Cressagian480.8 *
485 *
CambrianFurongianStage 10Cambrian 5485.4
Jiangshanian489.5
Paibian494
MiaolingianGuzhangianCambrian 4Series 3 †497
Drumian500.5
WuliuanCambrian 3Stage 5 †504.5
Series 2Stage 4509
Stage 3Cambrian 2514
TerreneuvianStage 2521
FortunianCambrian 1529
ProterozoicNeoproterozoicEdiacaranVendian †Poundian †538.8
Wonokan †571.7 *
635