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
J. Meng and M. C. McKenna. 1998. Faunal turnovers of Paleogene mammals from the Mongolian Plateau. Nature 394:364-367 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
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

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			Paleogene Mammal Ages of Asia		Cenozoic Subepochs	Obsolete Names for ICS Units			South American Land Mammal Ages		North American Land Mammal Ages	Ten Million Year Bins
Quaternary	Holocene	Meghalayan												Saintaugustinean	Cenozoic 6	0
		Meghalayan												Santarosean		0.0004
		Northgrippian														0.0042
		Greenlandian														0.0082
	Pleistocene	Late Pleistocene	Sheridanian					Late Pleistocene				Lujanian				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						Late Pliocene	Tertiary †			Vorohuean				2.58
		Piacenzian						Late Pliocene				Chapadmalalan				2.9 *
		Zanclean						Early Pliocene				Chapadmalalan				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						Early Miocene				Friasian				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				Tabenbulakian	Hsandagolian	Late Oligocene							Cenozoic 4	23.03
				Monroecreekian												23.1 *
				Geringian												24.7 *
		Rupelian				Kekeamuan		Early Oligocene								27.82
												Tinguirirican				28.9 *
														Whitneyan		29.5
														Orellan		31.8
	Eocene	Priabonian	Late Chadronian/Middle Chadronian/Early Chadronian			Houldjinian/Ergilian/Ulangochuian		Late Eocene						Chadronian	Cenozoic 3	33.9
			Late Chadronian/Middle Chadronian/Early Chadronian									Divisaderan		Chadronian		35.9 *
														Duchesnean		37
		Bartonian				Sharamurunian/Irdinmanhan/Arshantan		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					Bumbanian	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	Gashatan		Late Paleocene				Riochican		Clarkforkian	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			Middle Paleocene						Torrejonian		60.9
		Danian						Early Paleocene								61.6
												Tiupampan				62.4 *
					Pu3/Pu2/Pu1					Puercan	63.8	Tiupampan
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	Series 3 †	Cambrian 4	497
		Drumian		Cambrian 4	500.5
		Wuliuan		Stage 5 †	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