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
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
F. M. Gradstein, J. G. Ogg, M. D. Schmitz and G. M. Ogg. 2020. Geologic Time Scale 2020 view
A. D. Barnosky, M. Holmes, R. Kirchholtes, E. Lindsey, K.C. Maguire, A.W. Poust, M.A. Stegner, J. Sunseri, B. Swartz, J. Swift, N.A. Villavicencio and G. Wogan. 2014. Prelude to the Anthropocene: Two new North American Land Mammal Ages (NALMAs). The Anthropocene Review I(3):225-242 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 126610 collections

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International Chronostratigraphic Timescale			Ordovician of Britain				Ordovician of Ibero-Bohemia
Ordovician	Late Ordovician	Hirnantian	Ashgill	Hirnantian			Kosovian				443.8
		Katian		Rawtheyan			Kralodvorian	Bohdalec †			445.2
				Cautleyan							448.9 *
				Pusgillian							449.3 *
			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							458.4
							Dobrotivian				458.5 *
							Oretanian				459.7 *
				Abereiddian/Early Llanvirn							461.3 *
								Sarka †			461.7 *
		Dapingian						Klabava †			467.3
							Arenigian				468
			Arenig	Fennian							468.4 *
	Early Ordovician	Floian		Fennian							470
				Whitlandian							471.1 *
				Moridunian							474.3 *
		Tremadocian	Tremadoc	Migneintian			Tremadocian				477.7
			Tremadoc	Cressagian							480.8 *
											485 *
											485.4