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
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
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			Cenozoic Subepochs	Obsolete Names for ICS Units			North American Land Mammal Ages
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				Late Pleistocene				Rancholabrean	0.014
		Chibanian				Middle Pleistocene				Rancholabrean	0.129
		Chibanian	Cudahyan/Sappan			Middle Pleistocene				Irvingtonian	0.21
		Calabrian	Cudahyan/Sappan			Early Pleistocene				Irvingtonian	0.774
		Calabrian	Senecan/Rexroadian							Blancan	1.4
		Gelasian									1.8
Neogene	Pliocene	Piacenzian				Late Pliocene	Tertiary †				2.58
		Zanclean				Early Pliocene					3.6
		Zanclean	Late Hemphillian/late Early Hemphillian/early Early Hemphillian			Early Pliocene				Hemphillian	4.7
	Miocene	Messinian				Late Miocene					5.333
		Tortonian									7.246
		Tortonian	Late Clarendonian/Early Clarendonian							Clarendonian	9.4
		Serravallian	Late Clarendonian/Early Clarendonian			Middle Miocene				Clarendonian	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			Late Eocene				Chadronian	33.9
		Priabonian				Late Eocene				Duchesnean	37
		Bartonian				Middle Eocene				Duchesnean	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			Early Eocene				Bridgerian	47.8
			Lostcabinian/Lysitean/Graybullian/Sandcouleean							Wasatchian	50.5
					Cf3/Cf2/Cf1					Clarkforkian	54.9
	Paleocene	Thanetian			Cf3/Cf2/Cf1	Late Paleocene				Clarkforkian	56
		Thanetian			Ti6/Ti5/Ti4/Ti3/Ti2/Ti1	Late Paleocene				Tiffanian	56.2
		Selandian			Ti6/Ti5/Ti4/Ti3/Ti2/Ti1	Middle Paleocene				Tiffanian	59.2
		Selandian			To3/To2/To1	Middle Paleocene				Torrejonian	60.9
		Danian			To3/To2/To1	Early Paleocene				Torrejonian	61.6
		Danian			Pu3/Pu2/Pu1	Early Paleocene				Puercan	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
											509