PBDB Timescale

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
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
F. M. Gradstein, J. G. Ogg, M. D. Schmitz and G. M. Ogg. 2020. Geologic Time Scale 2020 view
B. D. Webby. 1998. Steps toward a global standard for Ordovician stratigraphy. Newsletters in Stratigraphy 36:1-33 view
F. M. Gradstein, J. G. Ogg, and A. G. Smith. 2004. A Geologic Time Scale 2004 1-589 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 126844 collections

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International Chronostratigraphic Timescale			Cambrian of Britain		Silurian of England		Ordovician of Britain				Cambrian of North America
Silurian	Pridoli				Red Downtonian/Temeside Shales/Downton Castle	Whitcliffe/Leintwardine							419.2
	Pridoli				Red Downtonian/Temeside Shales/Downton Castle	Bringewood/Elton							421.3
	Ludlow	Ludfordian			Coalbrookdale	Wenlock (England)/Tickwood							423
		Gorstian											425.6
		Gorstian				Buildwas							426.4 *
	Wenlock	Homerian				Buildwas							427.4
		Homerian			Wych	Woolhope							428.4 *
		Sheinwoodian											430.5
	Llandovery	Telychian											433.4
		Telychian											436.3 *
		Aeronian											438.5
		Aeronian			Cowleigh Park								439.3 *
		Rhuddanian			Cowleigh Park								440.8
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
							Tremadoc	Cressagian					480.8 *
													485 *
Cambrian	Furongian	Stage 10	Merioneth	Dolgellian/Trempealeauan								Franconian †/Dresbachian/Millardan	485.4
				Dolgellian/Trempealeauan							Sunwaptan		487.5
				Festiniogian									489.2 *
		Jiangshanian											489.5
											Steptoean		493 *
				Maentwrogian									493.1 *
		Paibian		Maentwrogian									494
	Miaolingian	Guzhangian	St Davids								Marjumian	Albertian †	497
		Drumian									Marjumian		500.5
		Wuliuan									Topazan		504.5
		Wuliuan									Delamaran		506.5
	Series 2	Stage 4	Caerfai								Delamaran	Waucoban †	509
		Stage 4									Dyeran		511 *
		Stage 3									Dyeran		514
											Montezuman		514.8 *
											Begadean		519.9 *
	Terreneuvian	Stage 2											521
	Terreneuvian	Fortunian											529
													538.8