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
  • B. D. Webby. 1998. Steps toward a global standard for Ordovician stratigraphy. Newsletters in Stratigraphy 36:1-33 view
  • F. M. Gradstein, J. G. Ogg, and A. G. Smith. 2004. A Geologic Time Scale 2004 1-589 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 126679 collections

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International Chronostratigraphic TimescaleObsolete Names for ICS UnitsOrdovician of the BalticCambrian EpochsCambrian of Australia
462.9
482.2
CambrianFurongianStage 10OelandPakerortLate CambrianDatsonian485.4 *
486.3 *
486.5
Payntonian486.8 *
JiangshanianIverian489.5
PaibianIdamean494
MiaolingianGuzhangianSeries 3 †Middle CambrianMindyallan497
Boomerangian499
DrumianUndillan500.5
Floran503
WuliuanStage 5 †Templetonian504.5
Ordian507.8 *
Series 2Stage 4Early Cambrian509
510.8 *
Stage 3514
TerreneuvianStage 2521
Fortunian529
538.8