Floium

from Wikipedia, the free encyclopedia
system series step ≈ age ( mya )
higher higher higher younger
Ordovician Upper Ordovician Brain antium 443.4
⬍
445.2
Katium 445.2
⬍
453
Sandbium 453
⬍
458.4
Middle Ordovician Darriwilium 458.4
⬍
467.3
Dapingium 467.3
⬍
470
Lower Ordovician Floium 470
⬍
477.7
Tremadocium 477.7
⬍
485.4
deeper deeper deeper older

The floium is the second chronostratigraphic stage of the Lower Ordovician series of the Ordovician in geological history . The beginning can be dated geochronologically to about 477.7 million years, the end to about 470 million years. The Floium follows the Tremadocium and is replaced by the Dapingium .

Naming and history

The stage is named after Flo in Västergötland (southern Sweden). The name was only proposed in 2004 by Stig M. Bergström , Anita Löfgren and Jörg Maletz. The Floium corresponds to the lower part of the earlier Arenigium series (or stage).

Definition and GSSP

The lower limit is defined with the first appearance of the graptolite species Tetragraptus approximatus . The upper limit of the Floium (or the lower limit of the subsequent stage of the Dapingium ) is defined by the first appearance of the conodont species Baltoniodus triangularis . The official reference profile (GSSP = "Global Stratotype Section and Point") for the Floium is located in the Diabasbrottet quarry, about 5 km northwest of the village of Flo in Västergötland ( southern Sweden ).

literature

  • SM Bergström, A. Löfgren and J. Maletz: The GSSP of the Second (Upper) Stage of the Lower Ordovician Series: Diabasbrottet at Hunneberg, Province of Västergötland, Southwestern Sweden. Episodes, 27 (4): 265-272, Beijing 2004 ISSN  0705-3797 PDF
  • Stig M. Bergström, Stanley C. Finney, Chen Xu, Daniel Goldman and Stephen A. Leslie: Three new Ordovician global stage names. Lethaia, 39: 287-288, Oslo 2006 ISSN  0024-1164 .
  • Felix Gradstein, Jim Ogg and Alan Smith: A Geologic timescale. Cambridge University Press 2004 ISBN 978-0-521-78673-7 .

Web links