Gutenstein formation

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Gutenstein formation on the summit of the Kasberg

The Gutenstein Formation , or the Gutenstein Strata , is a lithostratigraphic formation of the Middle Triassic in the Northern Limestone Alps and the Eastern Alpine Nappes of the Southern Limestone Alps . It is named after Gutenstein in the Piestingtal in Lower Austria.

history

The term Gutensteiner Kalk was invented in 1853 by F. v. Hauer shaped. The delimitation of the formation has long been inconsistent in the literature. In some cases, all of the stratified aniseed limestone and dolomite except for those of the Reifling formation were referred to as Gutenstein limestone .

Definition and distribution area

The Gutenstein Formation includes black, gray and brown, bituminous limestones with mostly thin stratification, white calcite veins and dolomitic inclusions. Alexander Tollmann differentiates between two main types of facies: an algae bio- sparit , which was formed at a shallow depth in moving water, and a micrite , which was formed at a somewhat greater depth. The formation can be found in the Northern Limestone Alps, in the Central Alpine Eastern Alpine Mesozoic and in the parts of the Southern Limestone Alps that geologically belong to the Eastern Alps, such as in the Drauzug . It is underlain by the Reichenhall Formation and overlaid by the Reifling Formation and the Wettersteinkalk Formation. With the exception of the basal parts, it can be replaced by the Steinalm formation . According to Tollmann, the Gutenstein formation near the Ötscher reaches a maximum thickness of around 250 meters, but it is usually well below that, around 100 meters. In the area of ​​the Hallstätter and Berchtesgaden facies, the thickness is significantly less. Chamanara determined a thickness of 331.5 meters for the Gutenstein formation in the eastern Karwendel.

In the Lienz Dolomites , in the Drauzug, the northern Carnic Alps , in Vorarlberg and Tyrol there is also the name Virgloria formation . With this distinction, heavily eroded limestones and laminites of a shallow water facies are to be separated from Gutenstein layers of a deep water facies.

Timeframe

According to Tollmann, the formation extends up to the end of the Middle Anise , and he dates the base layers to the area of ​​the border between the Lower and Middle Triassic.

Subdivision

Hamid Chamanara divides the Gutenstein formation in the eastern Karwendel into two members, namely a Plattenkalk and a Bankkalk. The Plattenkalk member is made of dark limestone and dolomite, which occur in alternating layers with Rauwacken . Wurstelkalke also occur locally , these are flat limestones with bulge-like irregularities on the layer surfaces, which may have been caused by bioturbation , i.e. by animals that have burrowed through the sediment. The bench limes are gray or dark gray, in the decimeter to meter range banked sequences.

Tollmann separates from the generally thin-banked Gutenstein limestone the thick-banked and somewhat lighter Annaberg limestone , which has a rich brachiopod fauna. According to Tollmann, the thickness of these limestone reaches around 100 meters in the western part of the Northern Limestone Alps and around 40 meters in the eastern part.

Fossil guide

Crinoids and brachiopods are relatively common , such as in the Karwendel or Kasberg in Upper Austria. A very rich ammonite fauna is known from the Rahnbauernkogel near Großreifling in the Ennstal . In contrast to the macrofauna, which is very rich in places, the microfauna is poor. There are foraminifera , silica sponge needles and, rarely, conodonts .

Individual evidence

  1. ↑ a b Alexander Tollmann: Analysis of the classical north Alpine Mesozoic. Stratigraphy, fauna and facies of the Northern Limestone Alps . (= Monograph of the Northern Limestone Alps. Part II). Verlag Deuticke, Vienna 1976, ISBN 3-7005-4412-X , p. 72.
  2. ^ Erich Thenius: Lower Austria. Geology of the Austrian federal states in brief individual representations. 2nd, expanded edition. Vienna 1974, p. 114.
  3. ↑ a b Alexander Tollmann: Analysis of the classical north Alpine Mesozoic. Stratigraphy, fauna and facies of the Northern Limestone Alps . (= Monograph of the Northern Limestone Alps. Part II). Verlag Deuticke, Vienna 1976, ISBN 3-7005-4412-X , p. 77.
  4. ↑ Hamid Chamanara: Geology, stratigraphy (Reichenhall and Gutenstein formation) and tectonics in the Stanser Joch area. Thesis. University of Innsbruck, 1994, p. 41.
  5. ^ Hugo Ortner: Report 2005 on geological recordings on the southern edge of the Kaisergebirge on sheet 90 Kufstein. ( PDF file , accessed June 30, 2009)
  6. ↑ T. Bechstädt , H. Mostler: Microfacies and microfauna of mid-Triadic basin sediments of the Northern Limestone Alps of Tyrol. ( PDF file , accessed June 30, 2009)
  7. ↑ Hamid Chamanara: Geology, stratigraphy (Reichenhall and Gutenstein formation) and tectonics in the Stanser Joch area. Thesis. University of Innsbruck, 1994, p. 41ff.
  8. ↑ Alexander Tollmann: Analysis of the classical North Alpine Mesozoic. Stratigraphy, fauna and facies of the Northern Limestone Alps . (= Monograph of the Northern Limestone Alps. Part II). Verlag Deuticke, Vienna 1976, ISBN 3-7005-4412-X , p. 80ff.