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
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
K. M. Cohen, S.C. Finney, P.L. Gibbard and J.-X. Fan. 2023. The ICS International Chronostratigraphic Chart v2023/09. 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
F. M. Gradstein, J. G. Ogg, and A. G. Smith. 2004. A Geologic Time Scale 2004 1-589 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			Obsolete Names for ICS Units			North American Land Mammal Ages	Cenozoic Subepochs
Quaternary	Holocene	Meghalayan							Saintaugustinean		0
		Meghalayan							Santarosean		0.0004
		Northgrippian									0.0042
		Greenlandian									0.0082
	Pleistocene	Late Pleistocene	Sheridanian							Late Pleistocene	0.0117
		Late Pleistocene							Rancholabrean	Late Pleistocene	0.014
		Chibanian							Rancholabrean	Middle Pleistocene	0.129
		Chibanian	Cudahyan/Sappan						Irvingtonian	Middle Pleistocene	0.21
		Calabrian	Cudahyan/Sappan						Irvingtonian	Early Pleistocene	0.774
		Calabrian	Senecan/Rexroadian						Blancan		1.4
		Gelasian									1.8
Neogene	Pliocene	Piacenzian				Tertiary †				Late Pliocene	2.58
		Zanclean								Early Pliocene	3.6
		Zanclean	Late Hemphillian/late Early Hemphillian/early Early Hemphillian						Hemphillian	Early Pliocene	4.7
	Miocene	Messinian								Late Miocene	5.333
		Tortonian									7.246
		Tortonian	Late Clarendonian/Early Clarendonian						Clarendonian		9.4
		Serravallian	Late Clarendonian/Early Clarendonian						Clarendonian	Middle Miocene	11.63
		Serravallian	late Late Barstovian/early Late Barstovian/Early Barstovian						Barstovian		12.5
		Langhian									13.82
		Burdigalian								Early Miocene	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								Late Oligocene	23.03
				Monroecreekian							23.1 *
				Geringian							24.7 *
		Rupelian		Geringian						Early Oligocene	27.82
									Whitneyan		29.5
									Orellan		31.8
	Eocene	Priabonian	Late Chadronian/Middle Chadronian/Early Chadronian						Chadronian	Late Eocene	33.9
		Priabonian							Duchesnean	Late Eocene	37
		Bartonian							Duchesnean	Middle Eocene	37.71
		Bartonian	Late Uintan/Early Uintan						Uintan		39.7
		Lutetian	Late Uintan/Early Uintan						Uintan		41.2
		Lutetian	Twinbuttean/Blacksforkian/Gardnerbuttian						Bridgerian		46.2
		Ypresian	Twinbuttean/Blacksforkian/Gardnerbuttian						Bridgerian	Early Eocene	47.8
			Lostcabinian/Lysitean/Graybullian/Sandcouleean						Wasatchian		50.5
					Cf3/Cf2/Cf1				Clarkforkian		54.9
	Paleocene	Thanetian			Cf3/Cf2/Cf1				Clarkforkian	Late Paleocene	56
		Thanetian			Ti6/Ti5/Ti4/Ti3/Ti2/Ti1				Tiffanian	Late Paleocene	56.2
		Selandian			Ti6/Ti5/Ti4/Ti3/Ti2/Ti1				Tiffanian	Middle Paleocene	59.2
		Selandian			To3/To2/To1				Torrejonian	Middle Paleocene	60.9
		Danian			To3/To2/To1				Torrejonian	Early Paleocene	61.6
		Danian			Pu3/Pu2/Pu1				Puercan	Early Paleocene	63.8
Cretaceous	Late Cretaceous	Maastrichtian									66
		Campanian									72.1
		Santonian									83.6
		Coniacian									86.3
		Turonian									89.8
		Cenomanian									93.9
	Early Cretaceous	Albian									100.5
		Aptian									113
		Barremian									121.4
		Hauterivian									125.77
		Valanginian									132.6
		Berriasian									139.8
Jurassic	Late Jurassic	Tithonian									145
		Kimmeridgian									149.2
		Oxfordian									154.8
	Middle Jurassic	Callovian									161.5
		Bathonian									165.3
		Bajocian									168.2
		Aalenian									170.9
	Early Jurassic	Toarcian					174.7
		Pliensbachian					184.2
		Sinemurian					192.9
		Hettangian					199.5
Triassic	Late Triassic	Rhaetian					201.4
		Norian					208.5
		Carnian					227
	Middle Triassic	Ladinian					237
	Middle Triassic	Anisian					242
	Early Triassic	Olenekian					247.2
	Early Triassic	Induan					251.2
Permian	Lopingian	Changhsingian					251.902
	Lopingian	Wuchiapingian					Longtanian †	254.14
	Guadalupian	Capitanian						259.51
		Wordian						264.28
		Roadian						266.9
	Cisuralian	Kungurian						273.01
		Artinskian						283.5
		Sakmarian						290.1
		Asselian						293.52
Carboniferous	Pennsylvanian	Gzhelian						298.9
		Kasimovian						303.7
		Moscovian						307
		Bashkirian						315.2
	Mississippian	Serpukhovian						323.2
		Visean						330.9
		Tournaisian						346.7
Devonian	Late Devonian	Famennian						358.9
	Late Devonian	Frasnian		372.2
	Middle Devonian	Givetian		382.7
	Middle Devonian	Eifelian		387.7
	Early Devonian	Emsian		393.3
		Pragian		407.6
		Lochkovian		410.8
Silurian	Pridoli			419.2
	Ludlow	Ludfordian		423
	Ludlow	Gorstian		425.6
	Wenlock	Homerian		427.4
	Wenlock	Sheinwoodian	430.5
	Llandovery	Telychian	433.4
		Aeronian	438.5
		Rhuddanian	440.8
Ordovician	Late Ordovician	Hirnantian	443.8
		Katian	445.2
		Sandbian	453
	Middle Ordovician	Darriwilian	458.4
	Middle Ordovician	Dapingian	467.3
	Early Ordovician	Floian	470
	Early Ordovician	Tremadocian	477.7
Cambrian	Furongian	Stage 10	485.4
		Jiangshanian	489.5
		Paibian	494
	Miaolingian	Guzhangian	Series 3 †	497
		Drumian		500.5
		Wuliuan		Stage 5 †	504.5
	Series 2	Stage 4			509
	Series 2	Stage 3			514
	Terreneuvian	Stage 2			521
	Terreneuvian	Fortunian			529
											538.8