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
  • M. Freudenthal. 2006. Mammal Paleogene zones. personal communication 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 TimescaleNorth American Mammal Subages/ZonesObsolete Names for ICS UnitsMammal Paleogene ZonesCenozoic Subepochs
QuaternaryPleistoceneLate PleistoceneSheridanianLate Pleistocene0.0117
ChibanianMiddle Pleistocene0.129
Cudahyan/Sappan0.21
CalabrianEarly Pleistocene0.774
Senecan/Rexroadian1.4
Gelasian1.8
NeogenePliocenePiacenzianTertiary †Late Pliocene2.58
ZancleanEarly Pliocene3.6
Late Hemphillian/late Early Hemphillian/early Early Hemphillian4.7
MioceneMessinianLate Miocene5.333
Tortonian7.246
Late Clarendonian/Early Clarendonian9.4
SerravallianMiddle Miocene11.63
late Late Barstovian/early Late Barstovian/Early Barstovian12.5
Langhian13.82
BurdigalianEarly Miocene15.98
Late Hemingfordian/Early Hemingfordian16.3
late Late Arikareean/early Late Arikareean/late Early Arikareean/early Early ArikareeanHarrisonian18.5
Aquitanian20.44
PaleogeneOligoceneChattianMP 30/MP 29/MP 28/MP 27/MP 26MP 25Late Oligocene23.03
Monroecreekian23.1 *
Geringian24.7 *
RupelianMP 24/MP 23/MP 22/MP 21Early Oligocene27.82
29.5
EocenePriabonianLate Chadronian/Middle Chadronian/Early ChadronianMP 20/MP 19/MP 18/MP 17B/MP 17ALate Eocene33.9
37
BartonianMP 16Middle Eocene37.71
Late Uintan/Early Uintan39.7
LutetianMP 15/MP 14/MP 13/MP 12/MP 1141.2
Twinbuttean/Blacksforkian/Gardnerbuttian46.2
YpresianMP 10/MP 8 + 9/MP 7Early Eocene47.8
Lostcabinian/Lysitean/Graybullian/Sandcouleean50.5
Cf3/Cf2/Cf154.9
PaleoceneThanetianMP 6MP 1 - 5Late Paleocene56
Ti6/Ti5/Ti4/Ti3/Ti2/Ti156.2
SelandianMiddle Paleocene59.2
To3/To2/To160.9
DanianEarly Paleocene61.6
Pu3/Pu2/Pu163.8
CretaceousLate CretaceousMaastrichtian66
Campanian72.1
Santonian83.6
Coniacian86.3
Turonian89.8
Cenomanian93.9
Early CretaceousAlbian100.5
Aptian113
Barremian121.4
Hauterivian125.77
Valanginian132.6
Berriasian139.8
JurassicLate JurassicTithonian145
Kimmeridgian149.2
Oxfordian154.8
Middle JurassicCallovian161.5
Bathonian165.3
Bajocian168.2
Aalenian170.9
Early JurassicToarcian174.7
Pliensbachian184.2
Sinemurian192.9
Hettangian199.5
TriassicLate TriassicRhaetian201.4
Norian208.5
Carnian227
Middle TriassicLadinian237
Anisian242
Early TriassicOlenekian247.2
Induan251.2
PermianLopingianChanghsingian251.902
WuchiapingianLongtanian †254.14
GuadalupianCapitanian259.51
Wordian264.28
Roadian266.9
CisuralianKungurian273.01
Artinskian283.5
Sakmarian290.1
Asselian293.52
CarboniferousPennsylvanianGzhelian298.9
Kasimovian303.7
Moscovian307
Bashkirian315.2
MississippianSerpukhovian323.2
Visean330.9
Tournaisian346.7
DevonianLate DevonianFamennian358.9
Frasnian372.2
Middle DevonianGivetian382.7
Eifelian387.7
Early DevonianEmsian393.3
Pragian407.6
Lochkovian410.8
SilurianPridoli419.2
LudlowLudfordian423
Gorstian425.6
WenlockHomerian427.4
Sheinwoodian430.5
LlandoveryTelychian433.4
Aeronian438.5
Rhuddanian440.8
OrdovicianLate OrdovicianHirnantian443.8
Katian445.2
Sandbian453
Middle OrdovicianDarriwilian458.4
Dapingian467.3
Early OrdovicianFloian470
Tremadocian477.7
CambrianFurongianStage 10485.4
Jiangshanian489.5
Paibian494
MiaolingianGuzhangianSeries 3 †497
Drumian500.5
WuliuanStage 5 †504.5
509