Geology of the Brenner Pass-Fortezza transect, Italian Eastern Alps

Abstract

We present a 1:30,000 geological map resulting from detailed geostructural surveys carried out along the Italian segment of the design corridor for the Brenner Pass railway base tunnel (BBT), extending from Fortezza (Italy) to Innsbruck (Austria). The map covers the southern part of the Austroalpine-Penninic collisional wedge, the Periadriatic Fault System, associated Oligocene igneous bodies (Periadriatic magmatism) and part of the Southalpine basement. The Penninic Zone in the western Tauern Window is represented by the double domal structure of the Europe-derived Tux and Venediger-Zillertal basement and cover nappe system, capped by the ophiolitic Glockner nappe. The overlying Austroalpine nappe system is here represented by the polymetamorphic Merano-Mules basement and minor cover sheets. The Southern Alps domain includes the Bressanone Granite and pre-granite quartz-phyllites. Four Alpine ductile deformation phases have been recognized, followed by ductile-brittle shear zones, and finally brittle deformations along faults with extensional and strike-slip kinematics. The Quaternary is characterized by glacial deposits, large gravitational mass movements and landslides.

Keywords:

• geological map
• structural geology
• Brenner base tunnel
• Tauern window
• Austroalpine-Penninic collisional wedge
• Eastern Alps
• Italy

Acknowledgements

We acknowledge BBT-SE for funding the field and laboratory work of the CFR project, providing the topographic maps and authorization to publish our scientific results. E. Fontana, B.J. Kronenfeld, P. Scandone are acknowledged for their careful reviews. Irene Vigni is thanked for her technical assistance.