Pragium

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system series step ≈ age ( mya )
higher higher higher younger
Devon Upper Devonian Family 358.9
⬍
372.2
Frasnium 372.2
⬍
382.7
Middle Devon Givetium 382.7
⬍
387.7
Eifelium 387.7
⬍
393.3
Lower Devon Emsium 393.3
⬍
407.6
Pragium 407.6
⬍
410.8
Lochkovium 410.8
⬍
419.2
deeper deeper deeper older

The Pragian ( English Pragian even Praghian) is in the Earth's history , a chronostratigraphic stage of the Devonian , the geochronological began about 410.8 million years and until about 407.6 million years lasted. On the Pragian follows Emsium . The pragium itself begins after the Lochkovium .

Naming and history

The pragium was named after the Czech city ​​of Prague . In 1958 the pragium was defined in the "Prager Arbeitstagung" as a level corresponding to the Praha formation. Later the upper part of the original pragium was separated and added to the emsium.

Definition and GSSP

The beginning of the pragium is defined by the first appearance of the conodont species Eognathodus sulcatus . The end marks the first appearance of Polygnathus kitabicus (= Polygnathus dehiscens ). The GSSP (globally valid type locality and type profile) is located in the southwest of Prague, in the Valká Chuchle quarry ( Czech Republic ).

Breakdown

The pragium is divided into three conodont biozones:

Central Europe at the time of the pragium

The Siegen layers ( Siegerland ) were partly deposited during the pragium, which is why the stage is also called Siegenium in German-language literature .

literature

  • Felix Gradstein, Jim Ogg, Jim, Alan Smith: A Geologic timescale. Cambridge University Press, 2004, ISBN 0-521-78673-8 .
  • Ivo Chlupác, William A. Oliver: Decision on the Lochkovian - Pragian Boundary Stratotype (Lower Devonian). In: Episodes. 12 (2), Beijing 1989, pp. 109-113. (PDF)
  • Eugeny A. Yolkin, AI Kim, Karsten Weddige , Jim A. Talent, Michael R. House: Definition of the Pragian / Emsian Stage boundary. In: Episodes. 20 (4), Beijing 1997, pp. 235-240. (PDF)

Web links