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
M. Freudenthal. 2006. Mammal Paleogene zones. personal communication 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
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
J. Palfy, P. L. Smith, and J. K. Mortensen. 2000. A U-Pb and 40Ar/39Ar time scale for the Jurassic. Canadian Journal of Earth Sciences 37(6):923-944 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 126710 collections

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International Chronostratigraphic Timescale			Ordovician of North America					Ordovician of Britain				Ordovician of Ibero-Bohemia
Ordovician	Late Ordovician	Hirnantian	Cincinnatian	Gamachian				Ashgill	Hirnantian			Kosovian				443.8
		Katian		Gamachian					Rawtheyan			Kralodvorian	Bohdalec †			445.2
				Richmondian					Rawtheyan							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 *
				Turinian						Actonian †						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
				Blackhillsian					Whitlandian							471.1 *
				Tulean					Whitlandian							473.9 *
									Moridunian							474.3 *
		Tremadocian						Tremadoc	Migneintian			Tremadocian				477.7
				Stairsian					Migneintian							480.3 *
				Stairsian					Cressagian							480.8 *
				Skullrockian/Demingian					Cressagian							482 *
				Skullrockian/Demingian												485 *
																485.4
																487.5