GeoWhen Database  

Introduction

Geologic Timeline
(No Stages)

Geologic Timeline
(With Stages)

A-Z Stage List

Regional Information

Download Files

  
                              Hirnantian ICS Stage
                                  (Gamachian)
 
                     From 445.6 +/- 1.5 To 443.7 +/- 1.5 Ma
 
  Start Defined By:  Potentially at base of the Normalograptus 
     extraordinarius-N. ojsuensis graptolite biozone.
  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_
 
 -- A Substage of --
  Eon:                  Phanerozoic     (542 - -5.5012e-005)
  Era:                  Paleozoic       (542 - 251)
  Period:               Ordovician      (488.3 - 443.7)
  Epoch:                Late Ordovician (460.9 - 443.7)
  Australian Stage:     Bolindian       (450 - 443.7)
  General Stage:        Ashgill         (449 - 443.7)
  North American Stage: Cincinnatian    (451 - 443.7)
 
 -- Preceeded By --
  ICS Stage:      Ordovician VI (455.8 - 445.6)
  European Stage: Rawtheyan     (446.5 - 445.6)
  Regional Stage: Richmondian   (449 - 445.6)
 
 -- 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)
 

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.