Steinalm formation

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The Steinalm Formation is a lithostratigraphic formation of the Middle Triassic in the Northern Limestone Alps . The formation, which is a maximum of 160 meters thick, represents the Gutenstein formation in some areas of the facies .

history

The term Steinalmkalk was coined in 1930 by J. Pia. Pia described the type locality near Saalfelden . Since the Steinalmkalk is difficult to distinguish from the Ladin Wettersteinkalk , the term was controversial at times.

Definition and distribution area

The Steinalm formation consists predominantly of light, massive, gray and gray-brown micritic or sparitic algae limestone, which can also be dolomitized. It is a shallow water formation. There are also darker and more strongly banked limes and dolomites. The Steinalm Formation is underlain by the lower strata of the Gutenstein Formation or Virgloria Formation and overlaid by the Wetterstein Formation , the Reifling Formation . Laterally, it is either interlocked with the upper strata of the Gutenstein Formation or the Virgloria Formation or represents them completely. At the type locality the formation reaches a thickness of 70 meters, at Großreifling in the Ennstal it is up to 100 meters thick, at Hohenberg in the Traisental it reaches a maximum of 160 meters. In the area of ​​Innsbruck's northern chain, its thickness varies between 15 and 116 meters. Sedimentation of the Steinalm Formation was ended by a transgression that drowned the carbonate platform and formed the basis for sedimentation of the Reifling Formation.

Timeframe

The formation has recently been dated to the top anise . A spread into the deeper Ladin is not excluded. Tollmann, on the other hand, dates the formation a little earlier, namely from the lower anise to the end of the central anise.

Fossil guide

Apart from dasycladaceae , which are spindle-shaped calcareous algae, macrofossils are sparse, brachiopods , cephalolopods and also crinoids can be found . Foraminifera such as Meandrospira dinarica , Pilammina densa or Glomospirella semiplana are found among the microfossils .

Zillkalk

The Zillkalk is the equivalent of the Steinalm formation in the Hallstatt zone. It is a reef limestone, which is underlain by the deep Anise Dolomites and overlaid by the Schreyeralm limestone . The name Zillkalk was coined by Marko Vincenc Lipold in the 19th century . The type locality is the Zill quarry near Hallein .

Individual evidence

  1. ↑ Alexander Tollmann: Analysis of the classical North Alpine Mesozoic. Stratigraphy, fauna and facies of the Northern Limestone Alps . Part II of the monograph of the Northern Limestone Alps, Verlag Deuticke, Vienna 1976, ISBN 3-7005-4412-X , p. 81.
  2. ↑ Petra Nittel, Contributions to the stratigraphy and micropalaeontology of the Central Triassic of the Innsbrucker Nordkette (Northern Limestone Alps, Austria), in Geo.Alp 3, 2006, pp. 93–145 PDF file , accessed on July 1, 2009.
  3. ↑ Dieter Zerbes, Ernst Ott: Geologie des Kaisergebirge (Tyrol) Brief explanations of the geological map 1: 25,000 and excursion suggestions , yearbook of the Geol. Bundesanstalt, vol. 142, Vienna 2000, p. 192f. PDF file , accessed on July 1, 2009.
  4. ↑ Alexander Tollmann: Analysis of the classical North Alpine Mesozoic. Stratigraphy, fauna and facies of the Northern Limestone Alps . Part II of the monograph of the Northern Limestone Alps, Verlag Deuticke, Vienna 1976, ISBN 3-7005-4412-X , p. 85.
  5. ↑ Petra Nittel, Contributions to the stratigraphy and micropalaeontology of the Central Triassic of the Innsbrucker Nordkette (Northern Limestone Alps, Austria), in Geo.Alp 3, 2006, pp. 93–145 PDF file , accessed on July 1, 2009.
  6. ↑ Dieter Zerbes, Ernst Ott: Geology of the Kaiser Mountains (Tyrol). Brief explanations of the geological map 1: 25,000 and excursion suggestions , yearbook of the Geol. Bundesanstalt, vol. 142, Vienna 2000, p. 192f. PDF file , accessed on July 1, 2009.
  7. ↑ Alexander Tollmann: Analysis of the classical North Alpine Mesozoic. Stratigraphy, fauna and facies of the Northern Limestone Alps . Part II of the monograph of the Northern Limestone Alps, Verlag Deuticke, Vienna 1976, ISBN 3-7005-4412-X , p. 86.

Web links

Stratigraphic table of Austria, PDF file