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, 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 126700 collections

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International Chronostratigraphic Timescale			Ordovician of Britain				Ordovician of China			Ordovician of Ibero-Bohemia
Ordovician	Late Ordovician	Hirnantian	Ashgill	Hirnantian			Hirnantian	Xiaoxita †/Shikou	Wufeng †	Kosovian				443.8
		Katian		Rawtheyan			Chientangkiangian			Kralodvorian	Bohdalec †			445.2
				Cautleyan										448.9 *
				Pusgillian										449.3 *
				Pusgillian			Neichianshanian/Hanjiang							449.5
			Caradoc	Streffordian	Onnian †									449.6 *
				Streffordian						Berounian				449.7 *
				Cheneyan										451.5 *
				Burrellian										452.7 *
		Sandbian												453
					Actonian †									453.2 *
					Marshbrookian †	Woolstonian †								454.2 *
					Longvillian †									455.2 *
												Zahorany †/Vinice	Letna †	456.2 *
				Aurelucian										456.8 *
					Soudleyan †/Harnagian/Costonian									457.4 *
					Soudleyan †/Harnagian/Costonian						Liben †			458 *
	Middle Ordovician	Darriwilian	Llanvirn	Llandeilian/Llandeilo/Late Llandeilo/Middle Llandeilo/Early Llandeilo/Late Llanvirn			Darriwilian	Guniu †/Hulo						458.4
										Dobrotivian				458.5 *
										Oretanian				459.7 *
				Abereiddian/Early Llanvirn										461.3 *
											Sarka †			461.7 *
								Hunjiang †	Dawan †/Daobaowan/Ningkuo		Sarka †			466.3 *
		Dapingian					Dapingian				Klabava †			467.3
										Arenigian				468
			Arenig	Fennian										468.4 *
	Early Ordovician	Floian		Fennian			Yiyangian							470
				Whitlandian										471.1 *
				Moridunian										474.3 *
		Tremadocian	Tremadoc	Migneintian			Xinchangian			Tremadocian				477.7
				Migneintian					Lianghekou †					477.9 *
				Cressagian										480.8 *
														485 *
														485.4