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                             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)
 

This page was automatically generated from the GeoWhen database (version 1.1.0).  Please read the introduction regarding the accuracy and reliability of this information.  Comments, corrections, and additions can be sent to geowhen@robertrohde.com.  References to published academic literature are preferred.

Introduction

Geologic Timeline
(No Stages)

Geologic Timeline
(With Stages)

A-Z Stage List

Regional Information

Download Files


2003-2005 GeoWhen Database
Prepared By Robert A. Rohde


This page was last updated on Tuesday, January 18, 2005.