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
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
B. D. Webby. 1998. Steps toward a global standard for Ordovician stratigraphy. Newsletters in Stratigraphy 36:1-33 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

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 127243 collections

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International Chronostratigraphic Timescale			Ordovician of China			Ordovician of Britain
Ordovician	Late Ordovician	Hirnantian	Hirnantian	Xiaoxita †/Shikou	Wufeng †	Ashgill	Hirnantian			443.8
		Katian	Chientangkiangian				Rawtheyan			445.2
							Cautleyan			448.9 *
							Pusgillian			449.3 *
			Neichianshanian/Hanjiang				Pusgillian			449.5
						Caradoc	Streffordian	Onnian †		449.6 *
							Cheneyan			451.5 *
							Burrellian			452.7 *
		Sandbian								453
								Actonian †		453.2 *
								Marshbrookian †	Woolstonian †	454.2 *
								Longvillian †		455.2 *
							Aurelucian	Longvillian †		456.8 *
							Aurelucian	Soudleyan †/Harnagian/Costonian		457.4 *
	Middle Ordovician	Darriwilian	Darriwilian	Guniu †/Hulo		Llanvirn	Llandeilian/Llandeilo/Late Llandeilo/Middle Llandeilo/Early Llandeilo/Late Llanvirn			458.4
				Guniu †/Hulo			Abereiddian/Early Llanvirn			461.3 *
				Hunjiang †	Dawan †/Daobaowan/Ningkuo					466.3 *
		Dapingian	Dapingian							467.3
		Dapingian	Dapingian			Arenig	Fennian			468.4 *
	Early Ordovician	Floian	Yiyangian				Fennian			470
							Whitlandian			471.1 *
							Moridunian			474.3 *
		Tremadocian	Xinchangian			Tremadoc	Migneintian			477.7
					Lianghekou †		Migneintian			477.9 *
							Cressagian			480.8 *
										485 *
										485.4