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
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
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
K. M. Cohen, S.C. Finney, P.L. Gibbard and J.-X. Fan. 2023. The ICS International Chronostratigraphic Chart v2023/09. 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		North American Land Mammal Ages	Cenozoic Subepochs	Ten Million Year Bins	Obsolete Names for ICS Units
Quaternary	Holocene	Meghalayan						Saintaugustinean		Cenozoic 6			0
		Meghalayan						Santarosean					0.0004
		Northgrippian											0.0042
		Greenlandian											0.0082
	Pleistocene	Late Pleistocene	Sheridanian			Lujanian			Late Pleistocene				0.0117
		Late Pleistocene						Rancholabrean	Late Pleistocene				0.014
		Chibanian						Rancholabrean	Middle Pleistocene				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		Tertiary †		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							Middle Miocene	Cenozoic 5			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							Late Oligocene	Cenozoic 4			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					Chadronian	Late Eocene	Cenozoic 3			33.9
			Late Chadronian/Middle Chadronian/Early Chadronian			Divisaderan		Chadronian					35.9 *
								Duchesnean					37
		Bartonian						Duchesnean	Middle Eocene				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		Clarkforkian	Late Paleocene	Cenozoic 1			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			Torrejonian	Middle Paleocene				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								Longtanian †		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	Series 3 †	497
		Drumian	Cambrian 4		500.5
		Wuliuan	Cambrian 3		Stage 5 †	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