Evolution of the Ötztal-Stubai, Scarl-Campo and Ulten Basement Units

Abstract

The Austro-Alpine basement, between the Tauern window to the E and the Western Alps to the W, treated in this contribution may be divided into three subunits due to differing lithology and metamorphic history. These three subunits, the Ötztal-Stubai-, the Scarl-Campo- and the Ulten basement, are divided by two major tectonic lines, the Schlinig line (ÖtztalStubai/Scarl-Campo) and the Peio line (Scarl-Campo/Ulten). Although each of the three units consists of quartzo-feldspatic and pelitic metasediments, acid to intermediate metamagmatites, in addition to metabasites and metacarbonates, the dominant rock types of the Ötztal-Stubai-, the Campo- and the Ulten-unit are metasediments. The Scarl unit however is mainly composed of acid metamagmatites. Ages of the acid magmatic protoliths are most probably Variscan in the Scarl unit and Caledonian in the Ötztal-Stubai unit.