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
  • A. D. Barnosky, M. Holmes, R. Kirchholtes, E. Lindsey, K.C. Maguire, A.W. Poust, M.A. Stegner, J. Sunseri, B. Swartz, J. Swift, N.A. Villavicencio and G. Wogan. 2014. Prelude to the Anthropocene: Two new North American Land Mammal Ages (NALMAs). The Anthropocene Review I(3):225-242 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
  • J. I. Raine, A. G. Beu, A. F. Boyes, H. J. Campbell, R. A. Cooper, J. S. Crampton, M. P. Crundwell, C. J. Hollis, and H. E. G. Morgans. 2015. Revised Calibration of the New Zealand Geological Timescale: NZGT2015/1. GNS Science Report 2012(39) 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
  • M. Kretzoi. 1942. Necroteuthis n. g. (Ceph. Dibr., Necroteuthidae N. F.) aus dem Oligozän von Budapest und das system der Dibranchiata. Földtani Közlöny 72:125-238 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 127057 collections

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International Chronostratigraphic TimescaleTen Million Year BinsOrdovician of Ibero-BohemiaOrdovician of North AmericaOrdovician of the Baltic
OrdovicianLate OrdovicianHirnantianOrdovician 5KosovianCincinnatianGamachianHarjuPorkuni443.8
KatianKralodvorianBohdalec †Pirgu445.2
Richmondian446 *
Vormsi449.6 *
Berounian449.7 *
MaysvillianRocklandian †/Shermanian/Ashbyan/Kirkfieldian/Blackriveran/Wildernessian/Trentonian/Franklinian449.8 *
NabalaJohvi †450 *
Edenian450.4 *
ViruRakvere450.6 *
MohawkianChatfieldian451.1 *
Oandu452 *
SandbianOrdovician 4KeilaIdavere †453
Turinian453.7 *
Haljala453.9
Zahorany †/ViniceLetna †456.2 *
Kukruse456.4 *
WhiterockianCanadian †Chazyan †/Marmor457 *
UhakuAluoja †457.5 *
Liben †458 *
Middle OrdovicianDarriwilianOrdovician 3458.4
Dobrotivian458.5 *
Lasnamagi458.9 *
Oretanian459.7 *
Aseri460.4 *
Sarka †461.7 *
OelandKunda462.9 *
Valaste †/Hunderum464.3 *
VolkhovLangevoja †/Vaana/Saka467.1 *
DapingianOrdovician 2Klabava †467.3
Arenigian468
Rangerian469.1 *
Billingen469.3 *
Early OrdovicianFloianIbexianBlackhillsianJeffersonian †Cassinian †470
Latorp †470.1 *
Hunneberg473.7 *
Tulean473.9 *
TremadocianOrdovician 1Tremadocian477.7
Stairsian480.3 *
Varangu481.3 *
Skullrockian/Demingian482 *
Pakerort482.2 *
485.4 *
486.3
486.5
487.5