PBDB Timescale

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

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 126762 collections

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International Chronostratigraphic Timescale			Ordovician of Britain				Silurian of England		Ordovician of Ibero-Bohemia
Silurian	Pridoli						Red Downtonian/Temeside Shales/Downton Castle	Whitcliffe/Leintwardine					419.2
	Pridoli						Red Downtonian/Temeside Shales/Downton Castle	Bringewood/Elton					421.3
	Ludlow	Ludfordian					Coalbrookdale	Wenlock (England)/Tickwood					423
		Gorstian											425.6
		Gorstian						Buildwas					426.4 *
	Wenlock	Homerian						Buildwas					427.4
		Homerian					Wych	Woolhope					428.4 *
		Sheinwoodian											430.5
	Llandovery	Telychian											433.4
		Telychian											436.3 *
		Aeronian											438.5
		Aeronian					Cowleigh Park						439.3 *
		Rhuddanian					Cowleigh Park						440.8
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