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
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, 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
F. M. Gradstein, J. G. Ogg, M. D. Schmitz and G. M. Ogg. 2020. Geologic Time Scale 2020 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
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. J. Prevosti, C. O. Romano, A. M. Forasiepi, S. Hemming, R. Bonini, A. M. Candela, E. Cerdeño, M. C. Madozzo Jaén, P. E. Ortiz, F. Pujos, L. Rasia, G. I. Schmidt, M. Taglioretti, R. D. E. MacPhee, and U. F. J. Pardiñas. 2021. New radiometric 40Ar–39Ar dates and faunistic analyses refine evolutionary dynamics of Neogene vertebrate assemblages in southern South America. Scientific Reports 2021(11):9830 view
J. J. Flynn and C. C. Swisher, III. 1995. Cenozoic South American Land Mammal Ages: correlation to global geochronology. Geochronology Time Scales and Global Stratigraphic Correlation, SEPM Special Publication 54:317-333 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 126662 collections

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International Chronostratigraphic Timescale			Mesozoic Subages		Ammonite Chrons of North America
Jurassic	Late Jurassic	Tithonian	Late Tithonian	Middle Tithonian				145
		Tithonian	Early Tithonian	Middle Tithonian				146.3 *
		Kimmeridgian	Late Kimmeridgian					149.2
		Kimmeridgian	Early Kimmeridgian					152.2 *
		Oxfordian	Late Oxfordian	Middle Oxfordian/Early Oxfordian				154.8
		Oxfordian		Middle Oxfordian/Early Oxfordian				157.9 *
	Middle Jurassic	Callovian	Late Callovian/Middle Callovian/Early Callovian					161.5
		Bathonian	Late Bathonian/Middle Bathonian/Early Bathonian					165.3
		Bajocian	Late Bajocian		Epizigzagiceras			168.2
			Late Bajocian		Rotundum/Oblatum/Kirschneri/Crassicostatus/Widebayense			168.4
			Early Bajocian		Rotundum/Oblatum/Kirschneri/Crassicostatus/Widebayense			168.6 *
		Aalenian	Late Aalenian/Middle Aalenian/Early Aalenian		Howelli/Scissum/Westermanni			170.9
	Early Jurassic	Toarcian	Late Toarcian		Yakounensis/Hillebrandti/Crassicosta			174.7
					Planulata			179.3 *
							Arnioceras arnouldi	179.8 *
			Middle Toarcian					180.4 *
					Kanense			181.3 *
					Carlottense			182.3 *
			Early Toarcian		Carlottense			182.9 *
			Early Toarcian		Kunae			183.5 *
		Pliensbachian	Late Pliensbachian/Early Pliensbachian		Kunae			184.2
					Freboldi			185.1 *
					Whiteavesi/Imlayi	Tetraspidoceras		186.2 *
						Tetraspidoceras		189.2 *
					Plesechioceras harbledownense/Asteroceras varians/Coroniceras	Canadensis		190.3 *
		Sinemurian	Late Sinemurian/Early Sinemurian					192.9
					Pseudaetomoceras		Psiloceras	196.4 *
					Franziceras/Euphyllites			196.5 *
		Hettangian	Late Hettangian/Middle Hettangian/Early Hettangian		Franziceras/Euphyllites			199.5
								201.4