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                              Llandovery Sub-Epoch
 
                     From 443.7 +/- 1.5 To 428.2 +/- 2.3 Ma
 
  Start Defined By:  Graptolites, lowest occurrences of Parakidograptus 
     acuminatus and Akidograptus ascensus.
  End Defined By:  Imprecise.  Between the base of acritarch biozone 5 and 
     extinction of conodont Pterospathodus amorphognathoides.  May be near base 
     of Cyrtograptus centrifugus 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:        Xiushanian (429 - 425.5)
  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)
 
 -- 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 --
  Sub-Epoch:        Wenlock      (428.2 - 422.9)
  ICS Stage:        Sheinwoodian (428.2 - 426.2)
  Australian Stage: Melbournian  (428.2 - 416)
 
 -- Contains the Following Stages --
  ICS Stage:            Rhuddanian  (443.7 - 439)
  ICS Stage:            Aeronian    (439 - 436)
  ICS Stage:            Telychian   (436 - 428.2)
  Australian Stage:     Keiloran    (443.7 - 433)
  Australian Stage:     Eildonian   (433 - 428.2)
  Chinese Stage:        Longmaxian  (443.7 - 438)
  Chinese Stage:        Shinulanian (438 - 433)
  Chinese Stage:        Baishaean   (433 - 429)
  North American Stage: Medinan     (443.7 - 438)
  Regional Stage:       Alexandrian (443.7 - 436)
  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.