Hettangian ICS Stage
From 199.6 +/- 0.6 To 196.5 +/- 1 Ma
Start Defined By: Near lowest occurrence of smooth Psiloceras planorbis
ammonite group.
End Defined By: Ammonite, lowest occurrence of arietitid genera Vermiceras
and Metophioceras.
Start Based On: Gradstein, Ogg, Smith, _A Geologic Time Scale 2004_
End Based On: Gradstein, Ogg, Smith, _A Geologic Time Scale 2004_
-- A Substage of --
Eon: Phanerozoic (542 - -5.5012e-005)
Era: Mesozoic (251 - 65.5)
Period: Jurassic (199.6 - 145.5)
Epoch: Early Jurassic (199.6 - 175.6)
New Zealand Stage: Aratauran (199.6 - 188)
-- Preceeded By --
Period: Triassic (251 - 199.6)
Epoch: Late Triassic (228 - 199.6)
ICS Stage: Rhaetian (203.6 - 199.6)
Chinese Stage: Erqiaoan (209 - 199.6)
New Zealand Stage: Otapirian (203 - 199.6)
-- Followed By --
ICS Stage: Sinemurian (196.5 - 189.6)
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