PBDB Interval

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
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
F. M. Gradstein, J. G. Ogg, M. D. Schmitz and G. M. Ogg. 2020. Geologic Time Scale 2020 view
F. M. Gradstein, J. G. Ogg, and A. G. Smith. 2004. A Geologic Time Scale 2004 1-589 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 127245 collections

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International Chronostratigraphic Timescale			Ten Million Year Bins	Ordovician of Britain
Ordovician	Late Ordovician	Hirnantian	Ordovician 5	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	Ordovician 4					453
						Actonian †		453.2 *
						Marshbrookian †	Woolstonian †	454.2 *
						Longvillian †		455.2 *
					Aurelucian	Longvillian †		456.8 *
					Aurelucian	Soudleyan †/Harnagian/Costonian		457.4 *
	Middle Ordovician	Darriwilian	Ordovician 3	Llanvirn	Llandeilian/Llandeilo/Late Llandeilo/Middle Llandeilo/Early Llandeilo/Late Llanvirn			458.4
		Darriwilian	Ordovician 3		Abereiddian/Early Llanvirn			461.3 *
		Dapingian	Ordovician 2		Abereiddian/Early Llanvirn			467.3
		Dapingian		Arenig	Fennian			468.4 *
	Early Ordovician	Floian			Fennian			470
					Whitlandian			471.1 *
					Moridunian			474.3 *
		Tremadocian	Ordovician 1	Tremadoc	Migneintian			477.7
				Tremadoc	Cressagian			480.8 *
								485 *
								485.4