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, and A. G. Smith. 2004. A Geologic Time Scale 2004 1-589 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
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 127248 collections
| International Chronostratigraphic Timescale | Silurian of North America | Ordovician of Britain | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Silurian | Pridoli | Cayugan | 419.2 | |||||||
| Niagaran | 422.5 * | |||||||||
| Ludlow | Ludfordian | 423 | ||||||||
| Gorstian | 425.6 | |||||||||
| Wenlock | Homerian | Lockportian | 427.4 | |||||||
| Sheinwoodian | 430.5 | |||||||||
| Llandovery | Telychian | Ontarian | 433.4 | |||||||
| Aeronian | 438.5 | |||||||||
| Alexandrian | 438.7 * | |||||||||
| Medinan | Clinton | 440.1 * | ||||||||
| 440.7 * | ||||||||||
| Rhuddanian | 440.8 | |||||||||
| Ordovician | Late Ordovician | Hirnantian | Ashgill | Hirnantian | 443.8 | |||||
| Katian | Rawtheyan | 445.2 | ||||||||
| Cautleyan | 448.9 * | |||||||||
| Pusgillian | 449.3 * | |||||||||
| Caradoc | Streffordian | Onnian † | 449.6 * | |||||||
| Cheneyan | 451.5 * | |||||||||
| Burrellian | 452.7 * | |||||||||
| Sandbian | 453 | |||||||||
| Actonian † | 453.2 * | |||||||||
| Marshbrookian † | Woolstonian † | 454.2 * | ||||||||
| Longvillian † | 455.2 * | |||||||||
| Aurelucian | 456.8 * | |||||||||
| Soudleyan †/Harnagian/Costonian | 457.4 * | |||||||||
| Middle Ordovician | Darriwilian | Llanvirn | Llandeilian/Llandeilo/Late Llandeilo/Middle Llandeilo/Early Llandeilo/Late Llanvirn | 458.4 | ||||||
| Abereiddian/Early Llanvirn | 461.3 * | |||||||||
| Dapingian | 467.3 | |||||||||
| Arenig | Fennian | 468.4 * | ||||||||
| Early Ordovician | Floian | 470 | ||||||||
| Whitlandian | 471.1 * | |||||||||
| Moridunian | 474.3 * | |||||||||
| Tremadocian | Tremadoc | Migneintian | 477.7 | |||||||
| Cressagian | 480.8 * | |||||||||
| 485 * | ||||||||||