Hohe Tauern window

The Tauern Window is a geological structure in the Austrian Central Alps. It is a region where a window (sometimes referred to by the German word: fenster) has been formed by uplift and erosion of the Austroalpine nappes to expose the rocks of the underlying Penninic nappes. The smaller Engadin window in western Austria/Switzerland, the Gargellen window in Vorarlberg and the Rechnitzer window in the Kőszeg Mountains of eastern Austria are all similar in nature and have similar origins.

Location

The Tauern window extends across parts of the Austrian provinces of Tyrol, Salzburg and Carinthia and from the Brenner Pass in the west to the Schladming – Mauterndorf line in the east, to the southwest it extends to Sterzing in the South Tyrol of Italy. It has a length of about 176 km from the south-west corner of the Brenner Pass to Schladming in the northeast and a north-south extension of about 30 km between Mittersill and Matrei. At its widest point between St Johann im Pongau and Spittal, it measures almost 54 km. The Tauern window encompasses most of the Zillertal Alps and the Hohe Tauern range.

The relatively hard rocks of the area are more resistant to erosion, so the area has high topographic relief and most of Austria's highest mountains, including the Großglockner 3,798 m (12,461 ft) and Großvenediger 3,674 m (12,054 ft), are within the area of the window.

The 55km long Brenner Base Tunnel (scheduled for completion in 2032) cuts through the western end of the Tauern window and runs approximately perpendicular to the fold axes of the upright folds of the Tauern window. The geophysical investigations and drill-cores collected during the three decades of site investigation before 2007, when construction of the tunnel started, along with observations made during the construction project, have provided a huge amount of geological and structural data which has helped to clarify many aspects of the Tauern window's geology.