GeoWhen Database  

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                           Alexandrian Regional Stage
 
                      From 443.7 +/- 1.5 To 436 +/- 1.9 Ma
 
  Start Defined By:  Graptolites, lowest occurrences of Parakidograptus 
     acuminatus and Akidograptus ascensus.
  End Defined By:  Brachiopods, just above extinction of Eocoelia intermedia 
     and below lowest succeeding species Eocoelia curtisi.  Near base of  
     Monograptus turriculatus graptolite zone.
 
  Start Based On:  Gradstein, Ogg, Smith, _A Geologic Time Scale 2004_
  End Based On:  Gradstein, Ogg, Smith, _A Geologic Time Scale 2004_
 
 -- Overlaps With --
  Chinese Stage:        Shinulanian (438 - 433)
  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)
  Australian Stage: Keiloran       (443.7 - 433)
 
 -- Preceeded By --
  Period:               Ordovician      (488.3 - 443.7)
  Epoch:                Late Ordovician (460.9 - 443.7)
  ICS Stage:            Hirnantian      (445.6 - 443.7)
  Australian Stage:     Bolindian       (450 - 443.7)
  General Stage:        Ashgill         (449 - 443.7)
  North American Stage: Cincinnatian    (451 - 443.7)
 
 -- Followed By --
  ICS Stage: Telychian (436 - 428.2)
 
 -- Contains the Following Stages --
  ICS Stage:            Rhuddanian (443.7 - 439)
  ICS Stage:            Aeronian   (439 - 436)
  Chinese Stage:        Longmaxian (443.7 - 438)
  North American Stage: Medinan    (443.7 - 438)
  Regional Stage:       Idwian     (439 - 437.5)
  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.