ABSTRACT
The Aicha and Mauls tunnels will pass through the tectonic unit of the Brixener granite, which belongs to the South Alpine unit. This unit contains these lithologies: granite, granodiorite, aplitic and pegmatitic veins. The Brixener granite (Figure 2) is a non-metamorphic tectonic unit, strongly deformed during the Alpine orogeny. The result of this deformation was to form a multitude of brittle joints and faults. The northernmost part of the project area, where the intermediate starting cut at Mauls and the last kilometres of the Aicha investigation tunnel are situated, lies within the area of the Periadriatic Seam. The Periadriatic Seam represents geologically the northern border of the South Alpine unit and is a dominant, predominantly west-east striking fault system characterised by brittle fracture.
