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
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
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 127243 collections

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International Chronostratigraphic Timescale			Ordovician of North America					Ordovician of Britain
Ordovician	Late Ordovician	Hirnantian	Cincinnatian	Gamachian				Ashgill	Hirnantian			443.8
		Katian		Gamachian					Rawtheyan			445.2
				Richmondian					Rawtheyan			446 *
									Cautleyan			448.9 *
									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 *
									Burrellian			452.7 *
		Sandbian										453
										Actonian †		453.2 *
				Turinian						Actonian †		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			458.4
		Darriwilian							Abereiddian/Early Llanvirn			461.3 *
		Dapingian							Abereiddian/Early Llanvirn			467.3
								Arenig	Fennian			468.4 *
				Rangerian								469.1 *
	Early Ordovician	Floian	Ibexian	Blackhillsian		Jeffersonian †	Cassinian †					470
				Blackhillsian					Whitlandian			471.1 *
				Tulean					Whitlandian			473.9 *
									Moridunian			474.3 *
		Tremadocian						Tremadoc	Migneintian			477.7
				Stairsian					Migneintian			480.3 *
				Stairsian					Cressagian			480.8 *
				Skullrockian/Demingian					Cressagian			482 *
				Skullrockian/Demingian								485 *
												485.4
												487.5