Geology of Austria

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The geology of Austria is very diverse due to its geological history. The landscapes of Austria reflect this geological diversity: from the rounded but massive forms of the Mühlviertel and Waldviertel to the fertile plains of the Danube lowlands, the Weinviertel and from Lower Austria to the steeply rising Alps , the Austrian landscapes are direct expressions of geological processes that almost go back a billion years.

Geological subdivision

Austria can be divided into several geological zones according to the types of rock that occur. These zones each have a similar rock and appearance.

Geological sketch of the Alps, in the right half Austria

The following zones can be distinguished from north to south:

Bohemian mass

The Bohemian Massif lies mostly north of the Danube and forms the Austrian granite and gneiss highlands ( Mühlviertel , Waldviertel ). It consists mainly of granite and gneiss and other igneous and metamorphic rocks . The Bohemian Massif is the oldest mountain range in Austria today; it was formed in the Precambrian and Paleozoic Era . Today it has flattened to a low mountain range through erosion .

Molasse basin

The Molasse Basin is geologically the most recent zone of Austria. It originated in the Tertiary and Quaternary and is therefore no more than 55 million years old. It includes the unfolded foreland molasse as well as the shingled and folded subalpine molasse or molasse zone immediately in front of the alpine body . In terms of landscape it is divided into the Danube region of Upper and Lower Austria , the Weinviertel , the Vienna , Graz and Klagenfurt basins and Burgenland . The Molasse Basin consists of deposit and sedimentary rocks from rivers and seas; especially clay and sandstone , marl and conglomerate . In the Molasse basin there are flat, sometimes wavy plains.

Flysch zone

The flysch zone belongs to the Pennine zone of the Alps . It stretches as a narrow seam from the Vienna Woods via Lower Austria , Upper Austria Salzburg and Bavaria to Vorarlberg . It arose in the Cretaceous period from the sea basin in front of the rising Alps. The main components are marl , clay slate and sandstone. In this area there are problems with frequent landslides due to the nature of the soil , hence the name of the zone ( Schwyzerdütsch “flyschen” means “flow”).

Northern Limestone Alps

Many of the well-known destinations of summer hiking tourism are in the rugged limestone mountains of the Northern Limestone Alps : the Hohe Wand , Schneeberg and Rax , Hochschwab , Dachstein , Totes Gebirge , Tennengebirge , Hochkönig , Steinernes Meer , Watzmann , Kaisergebirge , Karwendel , Wetterstein Mountains , the Lechtal Alps and the Allgäu Alps . Mainly made up of lime and dolomite , these mountain ranges are composed of organic sediments such as B. Corals and shells emerged in the Triassic and Jurassic and are good sites for fossils. The Northern Limestone Alps are originally on the northern edge of belonging to Africa microcontinent the Adriatic Plate incurred and as oberostalpiner ceiling stack pushed over in the Alps formation far beyond the southern edge of Europe.

Grauwackenzone

The Grauwackenzone is a relatively narrow strip in parts of Lower Austria , Styria , Salzburg and Tyrol and consists of metamorphic clay and sand slates. These rocks are from the Paleozoic and, compared to the other alpine rocks, very old, they form the original base of the Northern Limestone Alps and thus also of the Upper Eastern Alpine nappes. Most of the rocks form rather soft mountain shapes and are therefore very attractive for alpine skiing . On the other hand, a number of valuable mineral deposits are known in the Grauwackenzone ( iron ore , copper , magnesite , ...).

Central Alps

The Central Alps are a characteristic geological element of Austria. They consist of rocks that came to the surface after the metamorphic transformation process caused by the folding of the Alps. Put simply, it is the mountainous parts between the line Semmering - Upper Ennstal - Salzachtal - Inntal - Arlberg - Rätikon in the north and the Drautal in the south. Most of them belong to the Eastern Alpine nappes - with the exception of a few tectonic windows . Mountain groups such as the Ötztal Alps and the Lower Tauern should be emphasized .

Tauern, Engadine and Rechnitz windows

In the case of the Tauern , Engadine and Rechnitz windows, a deeper unit emerges as a tectonic window on the surface, which is covered by other layers in the rest of the Eastern Alps. This unit bears the name Penninikum and forms the bulk of the rocks in the Western Alps outside of Austria.

Periadriatic suture

The Periadriatic Seam is the border area between the Southern and Central Alps and represents a deep boundary between the rock layers, which follows the Gail and partly the Drava in its course . At the eastern edge of the Alps it splits up and the Sava Line turns primarily towards Slovenia - Croatia.

There are some late volcanic phenomena here, such as earthquakes - rare but quite violent - (for example the one in Friuli and Carinthia in 1348 ) and thermal springs .

Another fault line roughly follows the eastern roof of the Alps, but also extends over the Grazer Murtal into the Mur-Mürz-Furche , and over the Semmering to the Thermenland (this probably marks the boundary of the bedrock of the Pannonian basin to the the Alps are postponed here).

Southern Limestone Alps

The southern Limestone Alps are located in southern Carinthia and are very similar in appearance and components to the northern Limestone Alps. Geologically, they belong on the one hand to the Eastern Alps ( Drauzug or Gailtal Alps with Lienz Dolomites and Dobratsch as well as the northern edge of the Karawanken ), south of the Periadriatic Seam ( Gailtal - Rosental - Eisenkappel ), however, to the (eastern) southern Alps . Only the Carnic Alps , which belong to the southern Alps, are significantly older and comparable to the Grauwackenzone . However, like the Northern Limestone Alps, all are originally assigned to Africa.

See also

Web links

Individual evidence

  1. ↑ Historical earthquake research in Austria → Research. Central Institute for Meteorology and Geodynamics , accessed on November 16, 2008 .