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
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, and A. G. Smith. 2004. A Geologic Time Scale 2004 1-589 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

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		Ten Million Year Bins	Cenozoic Subepochs	North American Land Mammal Ages
Quaternary	Holocene	Meghalayan						Cenozoic 6		Saintaugustinean	0
		Meghalayan								Santarosean	0.0004
		Northgrippian									0.0042
		Greenlandian									0.0082
	Pleistocene	Late Pleistocene	Sheridanian			Lujanian			Late Pleistocene		0.0117
		Late Pleistocene							Late Pleistocene	Rancholabrean	0.014
		Chibanian							Middle Pleistocene	Rancholabrean	0.129
			Cudahyan/Sappan							Irvingtonian	0.21
						Ensenadan					0.3 *
		Calabrian							Early Pleistocene		0.774
			Senecan/Rexroadian							Blancan	1.4
						Sanandresian	Uquian †				1.7 *
		Gelasian				Sanandresian					1.8
Neogene	Pliocene	Piacenzian				Vorohuean			Late Pliocene		2.58
		Piacenzian				Chapadmalalan			Late Pliocene		2.9 *
		Zanclean				Chapadmalalan			Early Pliocene		3.6
						Montehermosan					3.7 *
			Late Hemphillian/late Early Hemphillian/early Early Hemphillian			Montehermosan				Hemphillian	4.7
						Huayquerian					4.9 *
	Miocene	Messinian							Late Miocene		5.333
		Tortonian									7.246
						Chasicoan					7.9 *
			Late Clarendonian/Early Clarendonian			Chasicoan				Clarendonian	9.4
						Mayoan					9.9 *
						Laventan					10.9 *
		Serravallian						Cenozoic 5	Middle Miocene		11.63
			late Late Barstovian/early Late Barstovian/Early Barstovian							Barstovian	12.5
						Colloncuran					13.7 *
		Langhian				Colloncuran					13.82
		Langhian				Friasian					15.4 *
		Burdigalian				Friasian			Early Miocene		15.98
						Santacrucian					16.2 *
			Late Hemingfordian/Early Hemingfordian			Santacrucian				Hemingfordian	16.3
			Late Hemingfordian/Early Hemingfordian			Colhuehuapian				Hemingfordian	17.4 *
			late Late Arikareean/early Late Arikareean/late Early Arikareean/early Early Arikareean	Harrisonian						Arikareean	18.5
		Aquitanian									20.44
		Aquitanian				Deseadan					20.9 *
Paleogene	Oligocene	Chattian						Cenozoic 4	Late Oligocene		23.03
				Monroecreekian							23.1 *
				Geringian							24.7 *
		Rupelian							Early Oligocene		27.82
						Tinguirirican					28.9 *
										Whitneyan	29.5
										Orellan	31.8
	Eocene	Priabonian	Late Chadronian/Middle Chadronian/Early Chadronian					Cenozoic 3	Late Eocene	Chadronian	33.9
			Late Chadronian/Middle Chadronian/Early Chadronian			Divisaderan				Chadronian	35.9 *
										Duchesnean	37
		Bartonian							Middle Eocene	Duchesnean	37.71
		Bartonian	Late Uintan/Early Uintan							Uintan	39.7
		Lutetian						Cenozoic 2			41.2
						Mustersan					41.9 *
			Twinbuttean/Blacksforkian/Gardnerbuttian							Bridgerian	46.2
		Ypresian							Early Eocene		47.8
						Casamayoran					47.9 *
			Lostcabinian/Lysitean/Graybullian/Sandcouleean							Wasatchian	50.5
					Cf3/Cf2/Cf1					Clarkforkian	54.9
	Paleocene	Thanetian			Cf3/Cf2/Cf1	Riochican		Cenozoic 1	Late Paleocene	Clarkforkian	56
					Ti6/Ti5/Ti4/Ti3/Ti2/Ti1	Riochican				Tiffanian	56.2
						Itaboraian					56.9 *
						Peligran					58.9 *
		Selandian							Middle Paleocene		59.2
		Selandian			To3/To2/To1				Middle Paleocene	Torrejonian	60.9
		Danian							Early Paleocene		61.6
						Tiupampan					62.4 *
					Pu3/Pu2/Pu1	Tiupampan				Puercan	63.8
Cretaceous	Late Cretaceous	Maastrichtian						Cretaceous 8			66
		Campanian						Cretaceous 7			72.1
		Santonian						Cretaceous 6			83.6
		Coniacian									86.3
		Turonian									89.8
		Cenomanian						Cretaceous 5			93.9
	Early Cretaceous	Albian						Cretaceous 4			100.5
		Aptian						Cretaceous 3			113
		Barremian						Cretaceous 2			121.4
		Hauterivian						Cretaceous 2			125.77
		Valanginian						Cretaceous 1			132.6
		Berriasian						Cretaceous 1			139.8
Jurassic	Late Jurassic	Tithonian						Jurassic 6			145
		Kimmeridgian					Jurassic 5	149.2
		Oxfordian						154.8
	Middle Jurassic	Callovian						161.5
		Bathonian					Jurassic 4	165.3
		Bajocian					Jurassic 4	168.2
		Aalenian					Jurassic 3	170.9
	Early Jurassic	Toarcian					Jurassic 3	174.7
		Pliensbachian					Jurassic 2	184.2
		Sinemurian					Jurassic 1	192.9
		Hettangian					Jurassic 1	199.5
Triassic	Late Triassic	Rhaetian					Triassic 4	201.4
		Norian					Triassic 4	208.5
		Carnian					Triassic 3	227
	Middle Triassic	Ladinian					Triassic 2	237
	Middle Triassic	Anisian					Triassic 2	242
	Early Triassic	Olenekian					Triassic 1	247.2
	Early Triassic	Induan					Triassic 1	251.2
Permian	Lopingian	Changhsingian					Permian 4	251.902
	Lopingian	Wuchiapingian						254.14
	Guadalupian	Capitanian						259.51
		Wordian						264.28
		Roadian					Permian 3	266.9
	Cisuralian	Kungurian					Permian 2	273.01
		Artinskian						283.5
		Sakmarian						290.1
		Asselian					Permian 1	293.52
Carboniferous	Pennsylvanian	Gzhelian					Carboniferous 5	298.9
		Kasimovian					Carboniferous 5	303.7
		Moscovian		Carboniferous 4			307
		Bashkirian		Carboniferous 4			315.2
	Mississippian	Serpukhovian		Carboniferous 3			323.2
		Visean		Carboniferous 2			330.9
		Tournaisian		Carboniferous 1			346.7
Devonian	Late Devonian	Famennian		Devonian 5			358.9
	Late Devonian	Frasnian		Devonian 4			372.2
	Middle Devonian	Givetian		Devonian 3			382.7
	Middle Devonian	Eifelian		Devonian 3			387.7
	Early Devonian	Emsian		Devonian 2			393.3
		Pragian		Devonian 1			407.6
		Lochkovian		Devonian 1			410.8
Silurian	Pridoli			Silurian 2			419.2
	Ludlow	Ludfordian	423
	Ludlow	Gorstian	425.6
	Wenlock	Homerian	427.4
	Wenlock	Sheinwoodian	430.5
	Llandovery	Telychian	Silurian 1	433.4
		Aeronian		438.5
		Rhuddanian		440.8
Ordovician	Late Ordovician	Hirnantian	Ordovician 5	443.8
		Katian	Ordovician 5	445.2
		Sandbian	Ordovician 4	453
	Middle Ordovician	Darriwilian	Ordovician 3	458.4
	Middle Ordovician	Dapingian	Ordovician 2	467.3
	Early Ordovician	Floian	Ordovician 2	470
	Early Ordovician	Tremadocian	Ordovician 1	477.7
Cambrian	Furongian	Stage 10	Cambrian 5	485.4
		Jiangshanian		489.5
		Paibian		494
	Miaolingian	Guzhangian	Cambrian 4	497
		Drumian	Cambrian 4	500.5
		Wuliuan	Cambrian 3	504.5
	Series 2	Stage 4	Cambrian 3	509
	Series 2	Stage 3	Cambrian 2	514
	Terreneuvian	Stage 2	Cambrian 2	521
	Terreneuvian	Fortunian	Cambrian 1	529
											538.8