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
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
B. D. Webby. 1998. Steps toward a global standard for Ordovician stratigraphy. Newsletters in Stratigraphy 36:1-33 view
D. H. Erwin and S. A. Bowring. 2004. Cambrian time scale. view
F. M. Gradstein, J. G. Ogg, and A. G. Smith. 2004. A Geologic Time Scale 2004 1-589 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 126679 collections

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International Chronostratigraphic Timescale			Ordovician of Ibero-Bohemia				Ordovician of China			Cambrian of Siberia
Ordovician	Late Ordovician	Hirnantian	Kosovian				Hirnantian	Xiaoxita †/Shikou	Wufeng †		443.8
		Katian	Kralodvorian	Bohdalec †			Chientangkiangian		Wufeng †		445.2
			Kralodvorian				Neichianshanian/Hanjiang				449.5
			Berounian								449.7 *
		Sandbian									453
					Zahorany †/Vinice	Letna †					456.2 *
				Liben †							458 *
	Middle Ordovician	Darriwilian					Darriwilian	Guniu †/Hulo			458.4
			Dobrotivian								458.5 *
			Oretanian								459.7 *
				Sarka †							461.7 *
				Sarka †				Hunjiang †	Dawan †/Daobaowan/Ningkuo		466.3 *
		Dapingian		Klabava †			Dapingian				467.3
		Dapingian	Arenigian				Dapingian				468
	Early Ordovician	Floian	Arenigian				Yiyangian				470
		Tremadocian	Tremadocian				Xinchangian				477.7
									Lianghekou †		477.9 *
									Lianghekou †	Mansian †	483.55 *
											485.4