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
J. A. Lillegraven and M. C. McKenna. 1986. Fossil mammals from the "Mesaverde" Formation (Late Cretaceous, Judithian) of the Bighorn and Wind River basins, Wyoming, with definitions of Late Cretaceous North American Land-Mammal "Ages". American Museum Novitates 2840:1-68 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 126701 collections

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International Chronostratigraphic Timescale			Ordovician of Britain				Ordovician of China			Ten Million Year Bins	Ordovician of Ibero-Bohemia
Ordovician	Late Ordovician	Hirnantian	Ashgill	Hirnantian			Hirnantian	Xiaoxita †/Shikou	Wufeng †	Ordovician 5	Kosovian				443.8
		Katian		Rawtheyan			Chientangkiangian				Kralodvorian	Bohdalec †			445.2
				Cautleyan											448.9 *
				Pusgillian											449.3 *
				Pusgillian			Neichianshanian/Hanjiang								449.5
			Caradoc	Streffordian	Onnian †										449.6 *
				Streffordian							Berounian				449.7 *
				Cheneyan											451.5 *
				Burrellian											452.7 *
		Sandbian								Ordovician 4					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			Darriwilian	Guniu †/Hulo		Ordovician 3					458.4
											Dobrotivian				458.5 *
											Oretanian				459.7 *
				Abereiddian/Early Llanvirn											461.3 *
												Sarka †			461.7 *
								Hunjiang †	Dawan †/Daobaowan/Ningkuo			Sarka †			466.3 *
		Dapingian					Dapingian			Ordovician 2		Klabava †			467.3
											Arenigian				468
			Arenig	Fennian											468.4 *
	Early Ordovician	Floian		Fennian			Yiyangian								470
				Whitlandian											471.1 *
				Moridunian											474.3 *
		Tremadocian	Tremadoc	Migneintian			Xinchangian			Ordovician 1	Tremadocian				477.7
				Migneintian					Lianghekou †						477.9 *
				Cressagian											480.8 *
															485 *
															485.4