PBDB Timescale

North American Mammal Subages/Zones

The interval definitions in this timescale are derived from the following sources:

M. O. Woodburne. 1987. A prospectus of the North American Mammal Ages. In: Woodburne, M. O. (ed.), Cenozoic Mammals of North America. University of California Press, Berkelery, CA 285-290 view
J. Alroy. 2000. New methods for quantifying macroevolutionary patterns and processes. Paleobiology 26(4):707-733 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 13 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 1028 collections

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International Chronostratigraphic Timescale			North American Mammal Subages/Zones			South American Land Mammal Ages
Quaternary	Holocene	Meghalayan						0
		Northgrippian						0.0042
		Greenlandian						0.0082
	Pleistocene	Late Pleistocene	Sheridanian			Lujanian		0.0117
		Chibanian	Sheridanian					0.129
			Cudahyan/Sappan					0.21
						Ensenadan		0.3 *
		Calabrian						0.774
			Senecan/Rexroadian					1.4
						Sanandresian	Uquian †	1.7 *
		Gelasian				Sanandresian		1.8
Neogene	Pliocene	Piacenzian				Vorohuean		2.58
		Piacenzian				Chapadmalalan		2.9 *
		Zanclean				Chapadmalalan		3.6
						Montehermosan		3.7 *
			Late Hemphillian/late Early Hemphillian/early Early Hemphillian			Montehermosan		4.7
						Huayquerian		4.9 *
	Miocene	Messinian						5.333
		Tortonian						7.246
						Chasicoan		7.9 *
			Late Clarendonian/Early Clarendonian			Chasicoan		9.4
						Mayoan		9.9 *
						Laventan		10.9 *
		Serravallian						11.63
			late Late Barstovian/early Late Barstovian/Early Barstovian					12.5
						Colloncuran		13.7 *
		Langhian				Colloncuran		13.82
		Langhian				Friasian		15.4 *
		Burdigalian				Friasian		15.98
						Santacrucian		16.2 *
			Late Hemingfordian/Early Hemingfordian			Santacrucian		16.3
			Late Hemingfordian/Early Hemingfordian			Colhuehuapian		17.4 *
			late Late Arikareean/early Late Arikareean/late Early Arikareean/early Early Arikareean	Harrisonian				18.5
		Aquitanian						20.44
		Aquitanian				Deseadan		20.9 *
Paleogene	Oligocene	Chattian						23.03
				Monroecreekian				23.1 *
				Geringian				24.7 *
		Rupelian						27.82
						Tinguirirican		28.9 *
								29.5
	Eocene	Priabonian	Late Chadronian/Middle Chadronian/Early Chadronian					33.9
			Late Chadronian/Middle Chadronian/Early Chadronian			Divisaderan		35.9 *
								37
		Bartonian						37.71
		Bartonian	Late Uintan/Early Uintan					39.7
		Lutetian						41.2
						Mustersan		41.9 *
			Twinbuttean/Blacksforkian/Gardnerbuttian					46.2
		Ypresian						47.8
						Casamayoran		47.9 *
			Lostcabinian/Lysitean/Graybullian/Sandcouleean					50.5
					Cf3/Cf2/Cf1			54.9
	Paleocene	Thanetian			Cf3/Cf2/Cf1	Riochican		56
					Ti6/Ti5/Ti4/Ti3/Ti2/Ti1	Riochican		56.2
						Itaboraian		56.9 *
						Peligran		58.9 *
		Selandian						59.2
		Selandian			To3/To2/To1			60.9
		Danian						61.6
						Tiupampan		62.4 *
					Pu3/Pu2/Pu1	Tiupampan		63.8
								66