Scythium

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system series step ≈  age  ( mya )
higher higher higher younger
 Triad  Upper Triassic  Rhaetium  201.3
⬍
208.5
 Norium 208.5
⬍
228
 Carnium 228
⬍
235
 Middle Triassic  Ladinium 235
⬍
242
 Anisium 242
⬍
247.2
 Lower Triassic   " Scythium "  247.2
⬍
251.2
deeper deeper deeper older

The Scythian (English Scythian or Scythian, in German usage mostly shortened to Scyth, also Scythian level or Scythian level) is a regional level of the Triassic , rarely used today , in the history of the earth . It is or was the only stage of the Lower Triassic. The original definition differed greatly from the later definition, which ultimately led to the abandonment or non-adoption of Scythian as a global level. The Scythian follows the Changhsingian ( Permian ) and is replaced by the Anisian (Middle Triassic). The turn of the Permian to Lower Triassic also operates locally as Permoskyth .

Concept history

In 1895, Edmund von Mojsisovics , Wilhelm Waagen and Carl Diener presented a comprehensive design for the first time to structure the pelagic triad. At that time it was divided into four series: the “Scythian series” was the lowest of the four series proposed by Wilhelm Waagen and Carl Diener. This was followed by the Dinaric, Tyrolean and Bavarian series, which Edmund von Mojsisovics dealt with. This four-part series structure of the triad has not caught on. Since 1902 at the latest, Carl Diener has been speaking of Scythian level instead of Scythian series. The interpretation of the Scythian as the lowest level of the Triassic became generally accepted in the following period. An explicit Derivatio nominis (name origin) do not give Libra and Diener. They only speak of the fact that the names for the individual levels and sub-levels of the Lower Triassic, which are proposed in this work, are "borrowed from the Asian region". One can assume that the name alludes to the tribe of the Scythians or their tribal area Scythia. The term Scythian (as a noun) has been used since Julius Pia at the latest.

Definition, absolute dating, correlation and subdivision

The beginning of the Scythian series was laid by scales and servants at the base of the Otoceras woodwardi ammonite zone. The top of the Flemingites flemingianus ammonite zone formed the upper limit . Thus the Scythian in this original definition only extends into the lower Olenekian . The base is also one ammonite zone higher than the currently defined base of the Indusium stage, the Lower Triassic series and the Triassic . Later the term was extended to the entire Lower Triassic, so that the Scythian corresponded to today's Lower Triassic series.

In the original definition by Scales and Servants, the Scythian would geochronologically encompass the period from 251 to 249 Ma before today, in the extended version (= lower Triassic series) the period from 251 to about 246 Ma.

The Scythian was generally equated with the Lower Triassic series. This means that the Scythian can be roughly equated with today's global levels of the Indusian and Olenekian. In the Alps, the Permian / Triassic border is mostly in terrestrial sedimentary rocks. Here the boundary Permian / Triassic is very difficult to determine biostratigraphically. Therefore the term Permo-Scyth or Permoskyth became common.

The “Scythian Series” was divided into two levels by scales and servants, a lower Brahmanic level and an upper Yakut level. The Brahmanic level was again divided into two lower levels, a lower Gangetic lower level and an upper Gandarian lower level.

Difficulties in defining it made Scythian appear unsuitable as a global stage. The Scythian is therefore only occasionally used in regional contexts in the Alps or the Alpidic mountains of Eastern Europe for stratigraphic structuring. Therefore, alternative proposals for subdividing the sub-triad series such as the four-level structure of Tozer, the three-level structure of Guex or the two-level structure of the Russian authors have been proposed, of which the latter has prevailed.

supporting documents

Individual evidence

  1. ^ Diener, Carl (1902): In memory of Albrecht von Krafft. Yearbook of the Imperial and Royal Geological Institute, 51: 149-158, Vienna. Online at archive.org (p. 156)
  2. ^ Pia, Julius (1930): Basic concepts of stratigraphy with extensive application to the European Middle Triassic. 252 pp., Deuticke, Leipzig & Vienna.
  3. ↑ TimeScale Creator 5.0 download page
  4. ^ Klaus, W. (1972): Possibilities of Stratigraphy in the "Permoskyth". Negotiations of the Federal Geological Institute, 1970: 33-34, Vienna PDF
  5. ^ Tozer, Edward Timothy (1965): Lower Triassic stages and ammonoid zones of Arctic Canada. Geological Survey of Canada Paper, 65-12: 1-14, Ottawa.
  6. ^ Guex, Jean (1978): Le Trias inférieur des Salt Ranges, Pakistan :problemèmes biochronologiques. Eclogae Geologicae Helvetiae, 71: 105-141, Basel. doi : 10.5169 / seals-164720

literature

  • Servant Carl (1915): The marine empires of the Triassic period. Memoranda of the Imperial Academy of Sciences in Vienna, mathematical and natural science class, 92: 405-549, Vienna.
  • Gradstein, Felix, James Ogg & Alan Smith (2004): A Geologic Time Scale 2004. 589 pp. Cambridge University Press, Cambridge ISBN 0521781426
  • Mojsisovics, Edmund von, Wilhelm Waagen & Carl Diener (1895): Draft of a structure of the pelagic sediments of the Triassic system. Session reports of the Imperial Academy of Sciences, mathematical and scientific class, 104: 1271–1302, Vienna.
  • Tozer, Edward Timothy (1967): A standard for Triassic time. Geological Survey of Canada Bulletin, 156: 1-103, Ottawa.

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