Geological map of the Klopai Pluton and its surroundings (Austroalpine Unit, Reschen Pass, Eastern Alps)

The Austroalpine Ötztal Nappe of the Eastern Alps preserves a polymetamorphic record ranging from pre-Ordovician to Alpine tectono-metamorphic events. In the Reschen Pass area (South Tyrol, Italy), Variscan mineral assemblages and a heterogeneous tectonic overprint coexist with possible pre-Variscan features, a rare occurrence in the Alpine Domain. We present a new 1:10,000 geological map of the area –geological mapping project, Autonomous Province of Bolzano– focusing on the Klopai tonalitic pluton and its surrounding lithologies. Detailed field mapping combined with petrographic characterization and structural analysis, reveal that migmatites occur exclusively at the contact with the pluton, whereas cordierite-bearing gneisses may mark the original contact aureole, suggesting a genetic link between pluton emplacement, contact metamorphism, and partial melting. Pegmatite dykes are associated with the pluton and its aureole, constraining the late magmatic stages. Our interpretation favours a relatively shallow emplacement (<10 km) during an early Paleozoic high-temperature event, broadly coeval with migmatization and regional crustal thinning. The overprinting Variscan deformation developed a penetrative foliation and high-grade mineral assemblages (staurolite, kyanite), while Alpine deformation is less recorded. These results refine the geological framework of the southwestern Ötztal Nappe, with implications for the reconstruction of the early Paleozoic geodynamics of the Gondwana margin.