Telychium

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system series step ≈ age ( mya )
higher higher higher younger
Silurian Pridolium 419.2
⬍
423
Ludlow Ludfordium 423
⬍
425.6
Gorstium 425.6
⬍
427.4
Wenlock Homerium 427.4
⬍
430.5
Sheinwoodium 430.5
⬍
433.4
Llandovery Telychium 433.4
⬍
438.5
Aeronium 438.5
⬍
440.8
Rhuddanium 440.8
⬍
443.4
deeper deeper deeper older

The telychium is the highest chronostratigraphic level of the Llandovery series of the Silurian in the history of the earth . Geochronologically, the stage corresponds roughly to the period from approx. 438.5 to approx. 433.4 million years. The Telychium follows the Aeronium and is in turn replaced by the Sheinwoodium .

Naming and history

The stage is named after the small town of Pen-lan-Telych , southeast of Llandovery ( Wales ). The stage (and name) was proposed in 1971 by a British group of geologists under LRM Cocks.

Definition and GSSP

The lower limit is above the extinction horizon of the brachiopod species Eocoelia intermedia and below the first appearance of the brachiopod species Eocoelia curtisi . The border is also near the base of the Monograptus turriculatus - graptolite zone. The upper limit of the level is so far only imprecisely determined. It is located between the base of acritarchs -Biozone 5 and the extinction of conodonts -Art Pterospathodus amorphognathoides . The boundary is likely also near the base of the Cyrtograptus centrifugus graptolite zone. The reference profile (GSSP = "Global Stratotype Section and Point") for the Telychium is located at location 162, transect d, at the Cefn Cerig farm or the road that leads to this farm at Llandovery (Wales).

literature

  • Felix Gradstein, Jim Ogg & Alan Smith: A Geologic timescale. Cambridge University Press 2004 ISBN 978-0-521-78673-7
  • LR Cocks: The Ordovician-Silurian Boundary. Episodes, 8 (2): 98-100, Beijing 1985 ISSN  0705-3797 .
  • LRM Cocks: The Llandovery Series in the Llandovery area. In: CH Holland and MG Bassett (eds.): A global standard for the Silurian System. National Museum of Wales, Geological Series 9: 36-50, Cardiff 1989 ZDB ID 995874-5 .
  • Charles H. Holland: Series and Stages of the Silurian System. Episodes, 8 (2): 101-103, Ottawa 1985 ISSN  0705-3797 .

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