The Tauern Window measures 160 kilometres in length and spans from the Brenner Pass in the west to Katschberg in the east. Its North-South axis is 30-60 kilometres in length. It includes to Zillertaller Alpen (Ziller valley Alps) and the Tuxer Alpen (Tux Alps), as well as the Hohe Tauern with the Venediger, the Granatspitz, the Grossglockner, the Sonnblick, the Goldberg, the Ankogel and the Hochalm groups.
Central gneiss formed from magma that solidifies to become granite, granodiorite and tonalite and later transformed to gneiss. The rocks of the crystalline basement are the Tauern Window's oldest rocks. The Habach Series named after the Habachtal (Habach valley) is the Lower Schist. The Upper Schist originated in the sedimentation basin of the Piemonte Ocean. This includes the limestone and dolomite deposited at the beginning of the Mesozoic era in the Tethys Ocean.
The Tauern Window is a geological sensation. The highest mountains in the Hohe Tauern region consist of rock strata that would otherwise be found in the lowest geological layers of the Alps. The Tauern Window lets you see these deep layers on the surface. It provides a view of the Earth's history stretching over millions of years. There are four massive gneiss cores at the centre of this geological window. These were created from liquid magma and formed the famous peaks such as the Grossvenediger and Hoher Sonnblick.