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
M. Freudenthal. 2006. Mammal Paleogene zones. personal communication 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			Mammal Paleogene 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				MP 30/MP 29/MP 28/MP 27/MP 26	MP 25	Late Oligocene					23.03
				Monroecreekian									23.1 *
				Geringian									24.7 *
		Rupelian		Geringian		MP 24/MP 23/MP 22/MP 21		Early Oligocene					27.82
												Whitneyan	29.5
												Orellan	31.8
	Eocene	Priabonian	Late Chadronian/Middle Chadronian/Early Chadronian			MP 20/MP 19/MP 18/MP 17B/MP 17A		Late Eocene				Chadronian	33.9
		Priabonian				MP 20/MP 19/MP 18/MP 17B/MP 17A		Late Eocene				Duchesnean	37
		Bartonian				MP 16		Middle Eocene				Duchesnean	37.71
		Bartonian	Late Uintan/Early Uintan			MP 16						Uintan	39.7
		Lutetian	Late Uintan/Early Uintan			MP 15/MP 14/MP 13/MP 12/MP 11						Uintan	41.2
		Lutetian	Twinbuttean/Blacksforkian/Gardnerbuttian			MP 15/MP 14/MP 13/MP 12/MP 11						Bridgerian	46.2
		Ypresian	Twinbuttean/Blacksforkian/Gardnerbuttian			MP 10/MP 8 + 9/MP 7		Early Eocene				Bridgerian	47.8
			Lostcabinian/Lysitean/Graybullian/Sandcouleean									Wasatchian	50.5
					Cf3/Cf2/Cf1							Clarkforkian	54.9
	Paleocene	Thanetian			Cf3/Cf2/Cf1	MP 6	MP 1 - 5	Late Paleocene				Clarkforkian	56
		Thanetian			Ti6/Ti5/Ti4/Ti3/Ti2/Ti1	MP 6		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