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
M. Kretzoi. 1942. Necroteuthis n. g. (Ceph. Dibr., Necroteuthidae N. F.) aus dem Oligozän von Budapest und das system der Dibranchiata. Földtani Közlöny 72:125-238 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 126701 collections

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International Chronostratigraphic Timescale			Ordovician of Britain				Ordovician of North America					Ordovician of Ibero-Bohemia
Ordovician	Late Ordovician	Hirnantian	Ashgill	Hirnantian			Cincinnatian	Gamachian				Kosovian				443.8
		Katian		Rawtheyan				Gamachian				Kralodvorian	Bohdalec †			445.2
				Rawtheyan				Richmondian								446 *
				Cautleyan												448.9 *
				Pusgillian												449.3 *
			Caradoc	Streffordian	Onnian †											449.6 *
												Berounian				449.7 *
								Maysvillian	Rocklandian †/Shermanian/Ashbyan/Kirkfieldian/Blackriveran/Wildernessian/Trentonian/Franklinian							449.8 *
								Edenian								450.4 *
							Mohawkian	Chatfieldian								451.1 *
				Cheneyan												451.5 *
				Burrellian												452.7 *
		Sandbian														453
					Actonian †											453.2 *
					Actonian †			Turinian								453.7 *
					Marshbrookian †	Woolstonian †										454.2 *
					Longvillian †											455.2 *
														Zahorany †/Vinice	Letna †	456.2 *
				Aurelucian												456.8 *
							Whiterockian		Canadian †	Chazyan †/Marmor						457 *
					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 *
								Rangerian								469.1 *
	Early Ordovician	Floian					Ibexian	Blackhillsian		Jeffersonian †	Cassinian †					470
				Whitlandian				Blackhillsian								471.1 *
				Whitlandian				Tulean								473.9 *
				Moridunian												474.3 *
		Tremadocian	Tremadoc	Migneintian								Tremadocian				477.7
				Migneintian				Stairsian								480.3 *
				Cressagian				Stairsian								480.8 *
				Cressagian				Skullrockian/Demingian								482 *
								Skullrockian/Demingian								485 *
																485.4
																487.5