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                               Ordovician Period
 
                     From 488.3 +/- 1.7 To 443.7 +/- 1.5 Ma
 
  Start Defined By:  Conodont, lowest occurrence of Iapetognathus fluctivagus; 
     just above base of Cordylodus lindstromi conodont Zone.  Just below lowest 
     occurrence of planktonic graptolites.
  End Defined By:  Graptolites, lowest occurrences of Parakidograptus 
     acuminatus and Akidograptus ascensus.
 
  Start Based On:  Gradstein, Ogg, Smith, _A Geologic Time Scale 2004_
  End Based On:  Gradstein, Ogg, Smith, _A Geologic Time Scale 2004_
 
 -- Overlaps With --
  North American Stage: Ibexian (491 - 471.8)
 
 -- A Substage of --
  Eon: Phanerozoic (542 - -5.5012e-005)
  Era: Paleozoic   (542 - 251)
 
 -- Preceeded By --
  Period:                  Cambrian      (542 - 488.3)
  Epoch:                   Late Cambrian (501 - 488.3)
  Australian Stage:        Payntonian    (491 - 488.3)
  Regional Stage:          Dolgellian    (492.5 - 488.3)
  Russian-Kazakhian Stage: Batyrbayan    (491.5 - 488.3)
 
 -- Followed By --
  Period:               Silurian       (443.7 - 416)
  Epoch:                Early Silurian (443.7 - 422.9)
  Sub-Epoch:            Llandovery     (443.7 - 428.2)
  ICS Stage:            Rhuddanian     (443.7 - 439)
  Australian Stage:     Keiloran       (443.7 - 433)
  Chinese Stage:        Longmaxian     (443.7 - 438)
  North American Stage: Medinan        (443.7 - 438)
  Regional Stage:       Alexandrian    (443.7 - 436)
 
 -- Contains the Following Epochs --
  Epoch: Early Ordovician  (488.3 - 471.8)
  Epoch: Middle Ordovician (471.8 - 460.9)
  Epoch: Late Ordovician   (460.9 - 443.7)
 

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.