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
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
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 127393 collections

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International Chronostratigraphic Timescale			Silurian of the Baltic	Silurian of North America			Ordovician of Britain
Silurian	Pridoli		Ohesaare	Cayugan							419.2
			Kaugetuma	Cayugan							421.7 *
			Kaugetuma	Niagaran							422.5 *
	Ludlow	Ludfordian	Kuressaare								423
		Ludfordian	Paadla								423.4 *
		Gorstian	Paadla								425.6
	Wenlock	Homerian	Rootsikula		Lockportian						427.4
		Homerian	Jaagarahu		Lockportian						429.2 *
		Sheinwoodian	Jaagarahu								430.5
		Sheinwoodian	Jaani								431.8 *
	Llandovery	Telychian	Jaani		Ontarian						433.4
		Telychian	Adavere								434 *
		Aeronian									438.5
						Alexandrian					438.7 *
			Raikkula								439.4 *
				Medinan	Clinton						440.1 *
											440.7 *
		Rhuddanian									440.8
		Rhuddanian	Juuru								441.4 *
Ordovician	Late Ordovician	Hirnantian					Ashgill	Hirnantian			443.8
		Katian						Rawtheyan			445.2
								Cautleyan			448.9 *
								Pusgillian			449.3 *
							Caradoc	Streffordian	Onnian †		449.6 *
								Cheneyan			451.5 *
								Burrellian			452.7 *
		Sandbian									453
									Actonian †		453.2 *
									Marshbrookian †	Woolstonian †	454.2 *
									Longvillian †		455.2 *
								Aurelucian	Longvillian †		456.8 *
								Aurelucian	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
		Dapingian					Arenig	Fennian			468.4 *
	Early Ordovician	Floian						Fennian			470
								Whitlandian			471.1 *
								Moridunian			474.3 *
		Tremadocian					Tremadoc	Migneintian			477.7
		Tremadocian					Tremadoc	Cressagian			480.8 *
											485 *