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
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
F. M. Gradstein, J. G. Ogg, M. D. Schmitz and G. M. Ogg. 2020. Geologic Time Scale 2020 view
F. M. Gradstein, J. G. Ogg, and A. G. Smith. 2004. A Geologic Time Scale 2004 1-589 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

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 125945 collections

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International Chronostratigraphic Timescale			Ten Million Year Bins	Ordovician of Ibero-Bohemia
Ordovician	Late Ordovician	Hirnantian	Ordovician 5	Kosovian				443.8
		Katian		Kralodvorian	Bohdalec †			445.2
		Katian		Berounian				449.7 *
		Sandbian	Ordovician 4					453
						Zahorany †/Vinice	Letna †	456.2 *
					Liben †			458 *
	Middle Ordovician	Darriwilian	Ordovician 3					458.4
				Dobrotivian				458.5 *
				Oretanian				459.7 *
					Sarka †			461.7 *
		Dapingian	Ordovician 2		Klabava †			467.3
		Dapingian		Arenigian				468
	Early Ordovician	Floian		Arenigian				470
	Early Ordovician	Tremadocian	Ordovician 1	Tremadocian				477.7
								485.4