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
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 126831 collections

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International Chronostratigraphic Timescale			Ordovician of Britain				Ordovician of North America					Ordovician of Australia
Ordovician	Late Ordovician	Hirnantian	Ashgill	Hirnantian			Cincinnatian	Gamachian				Bolindian	443.8
		Katian		Rawtheyan				Gamachian					445.2
				Rawtheyan				Richmondian					446 *
				Cautleyan									448.9 *
				Cautleyan								Eastonian	449 *
				Pusgillian									449.3 *
			Caradoc	Streffordian	Onnian †								449.6 *
								Maysvillian	Rocklandian †/Shermanian/Ashbyan/Kirkfieldian/Blackriveran/Wildernessian/Trentonian/Franklinian				449.8 *
								Edenian					450.4 *
							Mohawkian	Chatfieldian					451.1 *
				Cheneyan									451.5 *
				Cheneyan								Gisbornian	452 *
				Burrellian									452.7 *
		Sandbian											453
					Actonian †								453.2 *
					Actonian †			Turinian					453.7 *
					Marshbrookian †	Woolstonian †							454.2 *
					Longvillian †								455.2 *
				Aurelucian									456.8 *
							Whiterockian		Canadian †	Chazyan †/Marmor			457 *
					Soudleyan †/Harnagian/Costonian								457.4 *
	Middle Ordovician	Darriwilian	Llanvirn	Llandeilian/Llandeilo/Late Llandeilo/Middle Llandeilo/Early Llandeilo/Late Llanvirn								Darriwilian	458.4
		Darriwilian		Abereiddian/Early Llanvirn								Darriwilian	461.3 *
		Dapingian		Abereiddian/Early Llanvirn								Yapeenian	467.3
			Arenig	Fennian								Yapeenian	468.4 *
												Castlemainian	468.5 *
								Rangerian				Castlemainian	469.1 *
	Early Ordovician	Floian					Ibexian	Blackhillsian		Jeffersonian †	Cassinian †	Chewtonian	470
				Whitlandian								Chewtonian	471.1 *
												Bendigonian	471.8 *
												Lancefieldian	473.5 *
								Tulean					473.9 *
				Moridunian									474.3 *
		Tremadocian	Tremadoc	Migneintian									477.7
				Migneintian				Stairsian					480.3 *
				Cressagian				Stairsian					480.8 *
								Skullrockian/Demingian					482 *
												Warendian	482.8 *
												Warendian	485 *
													485.4
													487.5