Homerian ICS Stage
(Lockportian)
From 426.2 +/- 2.4 To 422.9 +/- 2.5 Ma
Start Defined By: Graptolite, lowest occurrence of Cyrtograptus lundgreni.
End Defined By: Imprecise. Just below base of local acritarch Leptobrachion
longhopense range zone. May be near base of Neodiversograptus nilssoni
graptolite zone.
Start Based On: Gradstein, Ogg, Smith, _A Geologic Time Scale 2004_
End Based On: Gradstein, Ogg, Smith, _A Geologic Time Scale 2004_
Global Stratotype Section and Point: Whitwell Coppice, Homer, Shropshire,
southwest England, UK
-- Overlaps With --
Chinese Stage: Xiushanian (429 - 425.5)
Chinese Stage: Guandian (425.5 - 422)
-- A Substage of --
Eon: Phanerozoic (542 - -5.5012e-005)
Era: Paleozoic (542 - 251)
Period: Silurian (443.7 - 416)
Epoch: Early Silurian (443.7 - 422.9)
Sub-Epoch: Wenlock (428.2 - 422.9)
Australian Stage: Melbournian (428.2 - 416)
North American Stage: Niagaran (438 - 421.3)
-- Preceeded By --
ICS Stage: Sheinwoodian (428.2 - 426.2)
-- Followed By --
Epoch: Late Silurian (422.9 - 416)
Sub-Epoch: Ludlow (422.9 - 418.7)
ICS Stage: Gorstian (422.9 - 421.3)
-- Contains the Following Stages --
Regional Stage: Whitwellian (426.2 - 425.4)
Regional Stage: Gleedonian (425.4 - 422.9)
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