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                             Idwian Regional Stage
 
                          From 439 +/- 1.8 To 437.5 Ma
 
  Start Defined By:  Graptolite, lowest occurrence of Monograptus austerus 
     sequens.
 
  Start Based On:  Gradstein, Ogg, Smith, _A Geologic Time Scale 2004_
 
 -- Overlaps With --
  Chinese Stage:        Longmaxian  (443.7 - 438)
  Chinese Stage:        Shinulanian (438 - 433)
  North American Stage: Medinan     (443.7 - 438)
  North American Stage: Niagaran    (438 - 421.3)
 
 -- 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:        Llandovery     (443.7 - 428.2)
  ICS Stage:        Aeronian       (439 - 436)
  Australian Stage: Keiloran       (443.7 - 433)
  Regional Stage:   Alexandrian    (443.7 - 436)
 
 -- Preceeded By --
  ICS Stage: Rhuddanian (443.7 - 439)
 
 -- Followed By --
  Regional Stage: Fronian (437.5 - 436)
 

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.