A tectonic window usually shows an extremely complex tectonic structure. A well-known example of this is the Tauern Window (TF) in the Eastern Alps of Europe. It is one of the largest tectonic windows in the world and consists of an upright folded stack of Penninic (Penninic Ocean) and sub-Penninic (Europe) nappes. These nappes were formed by the collision of the European and Adriatic plates and were folded upright and exposed in the Miocene by the northward thrust of the Dolomite indentation.

Despite decades of research, the recent deformation history of the Miocene TF, especially that of the western part, remains unclear. In this study, we perform a kinematic retrodeformation of a profile along the trace of the Brenner Base Tunnel and create a 3D model of the western TF. The 2D retrodeformation and the 3D model will serve as the basis for a 4D retrodeformation, which we will use to analyse the Miocene deformation history of the western TF as accurately as possible.

Figure: Results of the first project phase (2D-retro-deformation). a) present-day structure, b) Situation late Oligocene / early Miocene. Abbreviations: BNF - Brenner normal fault; DAV- Defereggen Antholz Vals fault; GFS - Giudicarie fault system; IF - Inntal fault; JF - Jaufen fault; KNF - Katschberg normal fault; MF - Mölltal fault; MMF - Meran Mauls fault; PGF - Pustertal Gailtal fault; PF - Passeier fault; SEMP - Salzach Ennstal Mariazell Puchberg fault; SMF - Sterzing Mauls fault; TW – Tauern Window; ZWD - Zwischenbergen Wöllatratten Drau fault.