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
  • F. F. Steininger, W. A. Berggren, D. V. Kent, R. L. Bernor, S. Sen and J. Agusti. 1996. Circum-Mediterranean Neogene (Miocene and Pliocene) marine-continental chronologic correlations of European mammal units. The Evolution of Western Eurasian Neogene Mammal Faunas (eds. R. L. Bernor, V. Fahlbusch, and H.-W. Mittmann) 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 126699 collections

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International Chronostratigraphic TimescaleOrdovician of AustraliaOrdovician of ChinaTen Million Year BinsOrdovician of North America
OrdovicianLate OrdovicianHirnantianBolindianHirnantianXiaoxita †/ShikouWufeng †Ordovician 5CincinnatianGamachian443.8
KatianChientangkiangian445.2
Richmondian446 *
Eastonian449 *
Neichianshanian/Hanjiang449.5
MaysvillianRocklandian †/Shermanian/Ashbyan/Kirkfieldian/Blackriveran/Wildernessian/Trentonian/Franklinian449.8 *
Edenian450.4 *
MohawkianChatfieldian451.1 *
Gisbornian452 *
SandbianOrdovician 4453
Turinian453.7 *
WhiterockianCanadian †Chazyan †/Marmor457 *
Middle OrdovicianDarriwilianDarriwilianDarriwilianGuniu †/HuloOrdovician 3458.4
Hunjiang †Dawan †/Daobaowan/Ningkuo466.3 *
DapingianYapeenianDapingianOrdovician 2467.3
Castlemainian468.5 *
Rangerian469.1 *
Early OrdovicianFloianChewtonianYiyangianIbexianBlackhillsianJeffersonian †Cassinian †470
Bendigonian471.8 *
Lancefieldian473.5 *
Tulean473.9 *
TremadocianXinchangianOrdovician 1477.7
Lianghekou †477.9 *
Stairsian480.3 *
Skullrockian/Demingian482 *
Warendian482.8 *
485.4
487.5