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. 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
F. M. Gradstein, F. P. Agterberg, J. G. Ogg, J. Hardenbol, P. Van Veen, J. Thierry, and Z. Huang. 1995. A Triassic, Jurassic, and Cretaceous time scale. SEPM Special Publication 54 view
M. Kretzoi. 1942. Necroteuthis n. g. (Ceph. Dibr., Necroteuthidae N. F.) aus dem Oligozän von Budapest und das system der Dibranchiata. Földtani Közlöny 72:125-238 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 126848 collections

Show more time

Show linear time

International Chronostratigraphic Timescale			Ordovician of Britain				Ordovician of China			Ordovician of North America
Ordovician	Late Ordovician	Hirnantian	Ashgill	Hirnantian			Hirnantian	Xiaoxita †/Shikou	Wufeng †	Cincinnatian	Gamachian				443.8
		Katian		Rawtheyan			Chientangkiangian				Gamachian				445.2
				Rawtheyan							Richmondian				446 *
				Cautleyan											448.9 *
				Pusgillian											449.3 *
				Pusgillian			Neichianshanian/Hanjiang								449.5
			Caradoc	Streffordian	Onnian †										449.6 *
											Maysvillian	Rocklandian †/Shermanian/Ashbyan/Kirkfieldian/Blackriveran/Wildernessian/Trentonian/Franklinian			449.8 *
											Edenian				450.4 *
										Mohawkian	Chatfieldian				451.1 *
				Cheneyan											451.5 *
				Burrellian											452.7 *
		Sandbian													453
					Actonian †										453.2 *
					Actonian †						Turinian				453.7 *
					Marshbrookian †	Woolstonian †									454.2 *
					Longvillian †										455.2 *
				Aurelucian											456.8 *
										Whiterockian		Canadian †	Chazyan †/Marmor		457 *
					Soudleyan †/Harnagian/Costonian										457.4 *
	Middle Ordovician	Darriwilian	Llanvirn	Llandeilian/Llandeilo/Late Llandeilo/Middle Llandeilo/Early Llandeilo/Late Llanvirn			Darriwilian	Guniu †/Hulo							458.4
				Abereiddian/Early Llanvirn				Guniu †/Hulo							461.3 *
								Hunjiang †	Dawan †/Daobaowan/Ningkuo						466.3 *
		Dapingian					Dapingian								467.3
			Arenig	Fennian											468.4 *
											Rangerian				469.1 *
	Early Ordovician	Floian					Yiyangian			Ibexian	Blackhillsian		Jeffersonian †	Cassinian †	470
				Whitlandian							Blackhillsian				471.1 *
				Whitlandian							Tulean				473.9 *
				Moridunian											474.3 *
		Tremadocian	Tremadoc	Migneintian			Xinchangian								477.7
									Lianghekou †						477.9 *
											Stairsian				480.3 *
				Cressagian							Stairsian				480.8 *
				Cressagian							Skullrockian/Demingian				482 *
											Skullrockian/Demingian				485 *
															485.4
															487.5