Ammonite Chrons of North America

The interval definitions in this timescale are derived from the following sources:

  • J. Palfy, P. L. Smith, and J. K. Mortensen. 2000. A U-Pb and 40Ar/39Ar time scale for the Jurassic. Canadian Journal of Earth Sciences 37(6):923-944 view
  • F. M. Gradstein, F. P. Agterberg, J. G. Ogg, J. Hardenbol, P. Van Veen, J. Thierry, and Z. Huang. 1995. A Triassic, Jurassic, and Cretaceous time scale. SEPM Special Publication 54 view
  • F. M. Gradstein, J. G. Ogg, M. D. Schmitz and G. M. Ogg. 2020. Geologic Time Scale 2020 view

There are 5 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 196 collections

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International Chronostratigraphic TimescaleAmmonite Chrons of North AmericaAmmonite Chrons of Northwest EuropeMesozoic SubagesTen Million Year Bins
QuaternaryHoloceneMeghalayanCenozoic 60
Northgrippian0.0042
Greenlandian0.0082
PleistoceneLate Pleistocene0.0117
Chibanian0.129
Calabrian0.774
Gelasian1.8
NeogenePliocenePiacenzian2.58
Zanclean3.6
MioceneMessinian5.333
Tortonian7.246
SerravallianCenozoic 511.63
Langhian13.82
Burdigalian15.98
Aquitanian20.44
PaleogeneOligoceneChattianCenozoic 423.03
Rupelian27.82
EocenePriabonianCenozoic 333.9
Bartonian37.71
LutetianCenozoic 241.2
Ypresian47.8
PaleoceneThanetianCenozoic 156
Selandian59.2
Danian61.6
CretaceousLate CretaceousMaastrichtianLate Maastrichtian/Early MaastrichtianCretaceous 866
CampanianLate Campanian/Middle Campanian/Early CampanianCretaceous 772.1
SantonianLate Santonian/Middle Santonian/Early SantonianCretaceous 683.6
ConiacianLate Coniacian/Middle Coniacian/Early Coniacian86.3
TuronianLate Turonian/Middle Turonian/Early Turonian89.8
CenomanianLate Cenomanian/Middle Cenomanian/Early CenomanianCretaceous 593.9
Early CretaceousAlbianLate AlbianCretaceous 4100.5
Middle Albian106.2 *
Early Albian109.9 *
AptianLate AptianCretaceous 3113
Early Aptian119.5 *
BarremianLate Barremian/Early BarremianCretaceous 2121.4
HauterivianLate Hauterivian/Early Hauterivian125.77
ValanginianLate Valanginian/Early ValanginianCretaceous 1132.6
BerriasianLate Berriasian139.8
Middle Berriasian140.6 *
Early Berriasian142.7 *
JurassicLate JurassicTithonianLate TithonianMiddle TithonianJurassic 6145
Early Tithonian146.3 *
KimmeridgianLate KimmeridgianJurassic 5149.2
Early Kimmeridgian152.2 *
OxfordianLate OxfordianMiddle Oxfordian/Early Oxfordian154.8
157.9 *
Middle JurassicCallovianLate Callovian/Middle Callovian/Early Callovian161.5
BathonianLate Bathonian/Middle Bathonian/Early BathonianJurassic 4165.3
BajocianEpizigzagicerasParkinsoni/Garantiana/Subfurcatum/Sauzei/Laeviuscula/DiscitesLate Bajocian168.2
Rotundum/Oblatum/Kirschneri/Crassicostatus/WidebayenseHumphresianum168.4
Early Bajocian168.6 *
AalenianHowelli/Scissum/WestermanniConcavum/Murchisonae/OpalinumLate Aalenian/Middle Aalenian/Early AalenianJurassic 3170.9
Early JurassicToarcianYakounensis/Hillebrandti/CrassicostaLevesquei/Variabilis/BifronsThouarsenseLate Toarcian174.7
Planulata179.3 *
Arnioceras arnouldi179.8 *
180.1
Middle Toarcian180.4 *
Kanense181.3 *
Serpentinum/Falciferum/Tenuicostatum182
Carlottense182.3 *
Early Toarcian182.9 *
Kunae183.5 *
PliensbachianSpinatum/Margaritatus/Davoei/Ibex/JamesoniLate Pliensbachian/Early PliensbachianJurassic 2184.2
Freboldi185.1 *
Whiteavesi/ImlayiTetraspidoceras186.2 *
189.2 *
Plesechioceras harbledownense/Asteroceras varians/CoronicerasCanadensis190.3 *
SinemurianRaricostatum/Oxynotum/Obtusum/Turneri/Semicostatum/BucklandiLate Sinemurian/Early SinemurianJurassic 1192.9
PseudaetomocerasPsiloceras196.4 *
Franziceras/Euphyllites196.5 *
HettangianAngulata/Liasicus/PlanorbisLate Hettangian/Middle Hettangian/Early Hettangian199.5
TriassicLate TriassicRhaetianTriassic 4201.4
NorianSevatian208.5
Alaunian213.2 *
Lacian216.7 *
CarnianTuvalianTriassic 3227
Julian233.4 *
Middle TriassicLadinianLongobardianTriassic 2237
Fassanian239.7 *
AnisianIllyrian242
Pelsonian243.8 *
Bithynian244.7 *
Aegean245.5 *
Early TriassicOlenekianSpathianTriassic 1247.2
Smithian248.9 *
InduanDienerian251.2
Griesbachian251.4 *
PermianLopingianChanghsingianPermian 4251.902
Wuchiapingian254.14
GuadalupianCapitanian259.51
Wordian264.28
RoadianPermian 3266.9
CisuralianKungurianPermian 2273.01
Artinskian283.5
Sakmarian290.1
AsselianPermian 1293.52
CarboniferousPennsylvanianGzhelianCarboniferous 5298.9
Kasimovian303.7
MoscovianCarboniferous 4307
Bashkirian315.2
MississippianSerpukhovianCarboniferous 3323.2
ViseanCarboniferous 2330.9
TournaisianCarboniferous 1346.7
DevonianLate DevonianFamennianDevonian 5358.9
FrasnianDevonian 4372.2
Middle DevonianGivetianDevonian 3382.7
Eifelian387.7
Early DevonianEmsianDevonian 2393.3
PragianDevonian 1407.6
Lochkovian410.8
SilurianPridoliSilurian 2419.2
LudlowLudfordian423
Gorstian425.6
WenlockHomerian427.4
Sheinwoodian430.5
LlandoveryTelychianSilurian 1433.4
Aeronian438.5
Rhuddanian440.8
OrdovicianLate OrdovicianHirnantianOrdovician 5443.8
Katian445.2
SandbianOrdovician 4453
Middle OrdovicianDarriwilianOrdovician 3458.4
DapingianOrdovician 2467.3
Early OrdovicianFloian470
TremadocianOrdovician 1477.7
CambrianFurongianStage 10Cambrian 5485.4
Jiangshanian489.5
Paibian494
MiaolingianGuzhangianCambrian 4497
Drumian500.5
WuliuanCambrian 3504.5
Series 2Stage 4509
Stage 3Cambrian 2514
TerreneuvianStage 2521
FortunianCambrian 1529
538.8