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
  • 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, 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
  • 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
  • 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 126778 collections

Show more time

Show linear time

International Chronostratigraphic TimescaleOrdovician of the BalticOrdovician of North America
OrdovicianLate OrdovicianHirnantianHarjuPorkuniCincinnatianGamachian443.8
KatianPirgu445.2
Richmondian446 *
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 OrdovicianDarriwilian458.4
Lasnamagi458.9 *
Aseri460.4 *
OelandKunda462.9 *
Valaste †/Hunderum464.3 *
VolkhovLangevoja †/Vaana/Saka467.1 *
Dapingian467.3
Rangerian469.1 *
Billingen469.3 *
Early OrdovicianFloianIbexianBlackhillsianJeffersonian †Cassinian †470
Latorp †470.1 *
Hunneberg473.7 *
Tulean473.9 *
Tremadocian477.7
Stairsian480.3 *
Varangu481.3 *
Skullrockian/Demingian482 *
Pakerort482.2 *
485.4 *
486.3
486.5
487.5