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
  • B. D. Webby. 1998. Steps toward a global standard for Ordovician stratigraphy. Newsletters in Stratigraphy 36:1-33 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

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 127243 collections

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International Chronostratigraphic TimescaleOrdovician of ChinaOrdovician of Britain
OrdovicianLate OrdovicianHirnantianHirnantianXiaoxita †/ShikouWufeng †AshgillHirnantian443.8
KatianChientangkiangianRawtheyan445.2
Cautleyan448.9 *
Pusgillian449.3 *
Neichianshanian/Hanjiang449.5
CaradocStreffordianOnnian †449.6 *
Cheneyan451.5 *
Burrellian452.7 *
Sandbian453
Actonian †453.2 *
Marshbrookian †Woolstonian †454.2 *
Longvillian †455.2 *
Aurelucian456.8 *
Soudleyan †/Harnagian/Costonian457.4 *
Middle OrdovicianDarriwilianDarriwilianGuniu †/HuloLlanvirnLlandeilian/Llandeilo/Late Llandeilo/Middle Llandeilo/Early Llandeilo/Late Llanvirn458.4
Abereiddian/Early Llanvirn461.3 *
Hunjiang †Dawan †/Daobaowan/Ningkuo466.3 *
DapingianDapingian467.3
ArenigFennian468.4 *
Early OrdovicianFloianYiyangian470
Whitlandian471.1 *
Moridunian474.3 *
TremadocianXinchangianTremadocMigneintian477.7
Lianghekou †477.9 *
Cressagian480.8 *
485 *
485.4