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
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 126108 collections

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International Chronostratigraphic Timescale			Ordovician of China			Ordovician of Britain				Ten Million Year Bins	Ordovician of Ibero-Bohemia
Ordovician	Late Ordovician	Hirnantian	Hirnantian	Xiaoxita †/Shikou	Wufeng †	Ashgill	Hirnantian			Ordovician 5	Kosovian				443.8
		Katian	Chientangkiangian				Rawtheyan				Kralodvorian	Bohdalec †			445.2
							Cautleyan								448.9 *
							Pusgillian								449.3 *
			Neichianshanian/Hanjiang				Pusgillian								449.5
						Caradoc	Streffordian	Onnian †							449.6 *
							Streffordian				Berounian				449.7 *
							Cheneyan								451.5 *
							Burrellian								452.7 *
		Sandbian								Ordovician 4					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	Darriwilian	Guniu †/Hulo		Llanvirn	Llandeilian/Llandeilo/Late Llandeilo/Middle Llandeilo/Early Llandeilo/Late Llanvirn			Ordovician 3					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							Ordovician 2		Klabava †			467.3
											Arenigian				468
						Arenig	Fennian								468.4 *
	Early Ordovician	Floian	Yiyangian				Fennian								470
							Whitlandian								471.1 *
							Moridunian								474.3 *
		Tremadocian	Xinchangian			Tremadoc	Migneintian			Ordovician 1	Tremadocian				477.7
					Lianghekou †		Migneintian								477.9 *
							Cressagian								480.8 *
															485 *
															485.4