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. J. Prevosti, C. O. Romano, A. M. Forasiepi, S. Hemming, R. Bonini, A. M. Candela, E. Cerdeño, M. C. Madozzo Jaén, P. E. Ortiz, F. Pujos, L. Rasia, G. I. Schmidt, M. Taglioretti, R. D. E. MacPhee, and U. F. J. Pardiñas. 2021. New radiometric 40Ar–39Ar dates and faunistic analyses refine evolutionary dynamics of Neogene vertebrate assemblages in southern South America. Scientific Reports 2021(11):9830 view
  • J. J. Flynn and C. C. Swisher, III. 1995. Cenozoic South American Land Mammal Ages: correlation to global geochronology. Geochronology Time Scales and Global Stratigraphic Correlation, SEPM Special Publication 54:317-333 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. O. Woodburne. 1987. A prospectus of the North American Mammal Ages. In: Woodburne, M. O. (ed.), Cenozoic Mammals of North America. University of California Press, Berkelery, CA 285-290 view
  • J. Alroy. 2000. New methods for quantifying macroevolutionary patterns and processes. Paleobiology 26(4):707-733 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
  • 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

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 126606 collections

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International Chronostratigraphic TimescaleOrdovician of ChinaOrdovician of the BalticOrdovician of North America
OrdovicianLate OrdovicianHirnantianHirnantianXiaoxita †/ShikouWufeng †HarjuPorkuniCincinnatianGamachian443.8
KatianChientangkiangianPirgu445.2
Richmondian446 *
Neichianshanian/Hanjiang449.5
Vormsi449.6 *
MaysvillianRocklandian †/Shermanian/Ashbyan/Kirkfieldian/Blackriveran/Wildernessian/Trentonian/Franklinian449.8 *
NabalaJohvi †450 *
Edenian450.4 *
ViruRakvere450.6 *
MohawkianChatfieldian451.1 *
Oandu452 *
SandbianKeilaIdavere †453
Turinian453.7 *
Haljala453.9
Kukruse456.4 *
WhiterockianCanadian †Chazyan †/Marmor457 *
UhakuAluoja †457.5 *
Middle OrdovicianDarriwilianDarriwilianGuniu †/Hulo458.4
Lasnamagi458.9 *
Aseri460.4 *
OelandKunda462.9 *
Valaste †/Hunderum464.3 *
Hunjiang †Dawan †/Daobaowan/Ningkuo466.3 *
VolkhovLangevoja †/Vaana/Saka467.1 *
DapingianDapingian467.3
Rangerian469.1 *
Billingen469.3 *
Early OrdovicianFloianYiyangianIbexianBlackhillsianJeffersonian †Cassinian †470
Latorp †470.1 *
Hunneberg473.7 *
Tulean473.9 *
TremadocianXinchangian477.7
Lianghekou †477.9 *
Stairsian480.3 *
Varangu481.3 *
Skullrockian/Demingian482 *
Pakerort482.2 *
485.4 *
486.3
486.5
487.5