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
  • D. H. Erwin and S. A. Bowring. 2004. Cambrian time scale. view
  • F. M. Gradstein, J. G. Ogg, and A. G. Smith. 2004. A Geologic Time Scale 2004 1-589 view
  • F. M. Gradstein, F. P. Agterberg, J. G. Ogg, J. Hardenbol, P. Van Veen, J. Thierry, and Z. Huang. 1995. A Triassic, Jurassic, and Cretaceous time scale. SEPM Special Publication 54 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

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 126691 collections

Show more time

Show linear time

International Chronostratigraphic TimescaleMesozoic Subages
TriassicLate TriassicRhaetian201.4
NorianSevatian208.5
Alaunian213.2 *
Lacian216.7 *
CarnianTuvalian227
Julian233.4 *
Middle TriassicLadinianLongobardian237
Fassanian239.7 *
AnisianIllyrian242
Pelsonian243.8 *
Bithynian244.7 *
Aegean245.5 *
Early TriassicOlenekianSpathian247.2
Smithian248.9 *
InduanDienerian251.2
Griesbachian251.4 *
251.902