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
A. D. Barnosky, M. Holmes, R. Kirchholtes, E. Lindsey, K.C. Maguire, A.W. Poust, M.A. Stegner, J. Sunseri, B. Swartz, J. Swift, N.A. Villavicencio and G. Wogan. 2014. Prelude to the Anthropocene: Two new North American Land Mammal Ages (NALMAs). The Anthropocene Review I(3):225-242 view
M. Freudenthal. 2006. Mammal Paleogene zones. personal communication view

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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.

This timescale is used in the definition of 1028 collections

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International Chronostratigraphic Timescale			North American Mammal Subages/Zones			North American Land Mammal Ages	Mammal Paleogene Zones
Quaternary	Holocene	Meghalayan				Saintaugustinean			0
		Meghalayan				Santarosean			0.0004
		Northgrippian							0.0042
		Greenlandian							0.0082
	Pleistocene	Late Pleistocene	Sheridanian						0.0117
		Late Pleistocene				Rancholabrean			0.014
		Chibanian				Rancholabrean			0.129
		Chibanian	Cudahyan/Sappan			Irvingtonian			0.21
		Calabrian	Cudahyan/Sappan			Irvingtonian			0.774
		Calabrian	Senecan/Rexroadian			Blancan			1.4
		Gelasian							1.8
Neogene	Pliocene	Piacenzian							2.58
		Zanclean							3.6
		Zanclean	Late Hemphillian/late Early Hemphillian/early Early Hemphillian			Hemphillian			4.7
	Miocene	Messinian							5.333
		Tortonian							7.246
		Tortonian	Late Clarendonian/Early Clarendonian			Clarendonian			9.4
		Serravallian	Late Clarendonian/Early Clarendonian			Clarendonian			11.63
		Serravallian	late Late Barstovian/early Late Barstovian/Early Barstovian			Barstovian			12.5
		Langhian							13.82
		Burdigalian							15.98
			Late Hemingfordian/Early Hemingfordian			Hemingfordian			16.3
			late Late Arikareean/early Late Arikareean/late Early Arikareean/early Early Arikareean	Harrisonian		Arikareean			18.5
		Aquitanian							20.44
Paleogene	Oligocene	Chattian					MP 30/MP 29/MP 28/MP 27/MP 26	MP 25	23.03
				Monroecreekian					23.1 *
				Geringian					24.7 *
		Rupelian		Geringian			MP 24/MP 23/MP 22/MP 21		27.82
						Whitneyan			29.5
						Orellan			31.8
	Eocene	Priabonian	Late Chadronian/Middle Chadronian/Early Chadronian			Chadronian	MP 20/MP 19/MP 18/MP 17B/MP 17A		33.9
		Priabonian				Duchesnean	MP 20/MP 19/MP 18/MP 17B/MP 17A		37
		Bartonian				Duchesnean	MP 16		37.71
		Bartonian	Late Uintan/Early Uintan			Uintan	MP 16		39.7
		Lutetian	Late Uintan/Early Uintan			Uintan	MP 15/MP 14/MP 13/MP 12/MP 11		41.2
		Lutetian	Twinbuttean/Blacksforkian/Gardnerbuttian			Bridgerian	MP 15/MP 14/MP 13/MP 12/MP 11		46.2
		Ypresian	Twinbuttean/Blacksforkian/Gardnerbuttian			Bridgerian	MP 10/MP 8 + 9/MP 7		47.8
			Lostcabinian/Lysitean/Graybullian/Sandcouleean			Wasatchian			50.5
					Cf3/Cf2/Cf1	Clarkforkian			54.9
	Paleocene	Thanetian			Cf3/Cf2/Cf1	Clarkforkian	MP 6	MP 1 - 5	56
		Thanetian			Ti6/Ti5/Ti4/Ti3/Ti2/Ti1	Tiffanian	MP 6		56.2
		Selandian			Ti6/Ti5/Ti4/Ti3/Ti2/Ti1	Tiffanian			59.2
		Selandian			To3/To2/To1	Torrejonian			60.9
		Danian			To3/To2/To1	Torrejonian			61.6
		Danian			Pu3/Pu2/Pu1	Puercan			63.8
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