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                              Early Silurian Epoch
                                (Lower Silurian)
 
                     From 443.7 +/- 1.5 To 422.9 +/- 2.5 Ma
 
  Start Defined By:  Graptolites, lowest occurrences of Parakidograptus 
     acuminatus and Akidograptus ascensus.
  End Defined By:  Imprecise.  Just below base of local acritarch Leptobrachion 
     longhopense range zone.  May be near base of Neodiversograptus nilssoni 
     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 --
  Australian Stage:     Melbournian (428.2 - 416)
  Chinese Stage:        Guandian    (425.5 - 422)
  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)
 
 -- 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 --
  Epoch:     Late Silurian (422.9 - 416)
  Sub-Epoch: Ludlow        (422.9 - 418.7)
  ICS Stage: Gorstian      (422.9 - 421.3)
 
 -- Contains the Following Sub-Epochs --
  Sub-Epoch: Llandovery (443.7 - 428.2)
  Sub-Epoch: Wenlock    (428.2 - 422.9)
 

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.