Sheinwoodian ICS Stage
(Tonawandian)
From 428.2 +/- 2.3 To 426.2 +/- 2.4 Ma
Start Defined By: Imprecise. Between the base of acritarch biozone 5 and
extinction of conodont Pterospathodus amorphognathoides. May be near base
of Cyrtograptus centrifugus graptolite zone.
End Defined By: Graptolite, lowest occurrence of Cyrtograptus lundgreni.
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: Hughley Brook, Apedale, Shropshire,
southwest England, UK
-- 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)
Chinese Stage: Xiushanian (429 - 425.5)
North American Stage: Niagaran (438 - 421.3)
-- Preceeded By --
Sub-Epoch: Llandovery (443.7 - 428.2)
ICS Stage: Telychian (436 - 428.2)
Australian Stage: Eildonian (433 - 428.2)
-- Followed By --
ICS Stage: Homerian (426.2 - 422.9)
Regional Stage: Whitwellian (426.2 - 425.4)
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