- 1LIAG Institute for Applied Geophysics, Hannover, Germany
- 2Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
- 3University of Innsbruck, Innsbruck, Austria
- 4Leibniz University Hannover, Hannover, Germany
- 5University of Glasgow, Glasgow, Scotland
The Tauern Window (TW) in the European Eastern Alps is one of Earth’s largest tectonic windows. It comprises nappes that were formed by the southward subduction of the European plate beneath the Adriatic plate. These nappes were stacked during the Late Eocene and, subsequently refolded during the Miocene due to the northward push of the eastern Southalpine Indenter. This process exhumed the western TW by up to 25 km, and coevally caused lateral escape and extensional tectonics. However, the Miocene deformation history of the western TW is still under ongoing debate. This study focuses on the Miocene deformation history of the western TW using 2-D, 3-D, and 4-D approaches.
We first restore a N-S oriented cross-section along the Brenner Base Tunnel using published zircon fission-track and P-T data. Restoration reveals two deformation phases: upright folding of the top of the nappe stack started to cease around 17 Ma, followed by thrusting of the entire nappe stack along the Sub-Tauern ramp. Contemporaneously, the hanging-wall nappes experienced 44–50% thinning due to W–E extension.
Our static 3-D reconstruction of the present-day structure of the western TW integrates published maps, cross-sections, and structural field data. The model discloses lateral structural changes, e.g., the transition of upright folds in the east into overturned folds in the west with varying plunge of the fold axes. We hypothesize that detachment of the lower crust of the eastern Southalpine Indenter caused different styles of deformation in front of it during indentation.
To prove our hypothesis, we restore the western TW in 4-D using the same method as for our 2-D reconstruction. We displace the nappe stack of the western TW downwards along the Sub-Tauern ramp (ca. 10 km over 15 Ma), followed by unfolding under high-temperature conditions, which allows viscous deformation. Finally, we will integrate strain information to restore the component of lateral escape.
How to cite: Tanner, D., Rudmann, J., Stipp, M., Pomella, H., Brandes, C., and Eizenhöfer, P.: 4-D kinematic restoration of the western Tauern Window (European Eastern Alps), EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-10544, https://doi.org/10.5194/egusphere-egu25-10544, 2025.
