Besides the Variscan and Alpine metamorphism, distinct upper Austroalpine units were influenced by a high temperature/low pressure (HT/LP) metamorphic event during Permian and Triassic times. This event is characterized by an increased geothermal gradient from about 45C/km. In some special areas with a low Eoalpine and Alpine metamorphic influence, mineral assemblages with andalusite and sillimanite are still present. This thesis focuses on the structural and geochemical analysis of two areas belonging to the Drauzug Gurktal nappe system. Area (a) is located near Dravograd (Slovenia), area (b) near Flattach between Möll,- and Drau valley (Carinthia). Both areas are situated south of the Southern Limit of Alpine Metamorphism (SAM) and sillimanite indicates a HT/LP metamorphism and is formed by the breakdown of garnet and muscovite to sillimanite, biotite and H2O. The sillimanite paragneisses mainly consist of quartz, biotite, sillimanite, feldspar, garnet, muscovite, clinozoisite, chlorite, monazite, and zircon. Staurolites and amphiboles are only preserved as relicts. Rb/Sr biotite age dating yielded 150 Ma which can be interpreted as a cooling age below 300 50C. Grt/Bt geothermical calculations resulted in temperatures around 650C which imply amphibolite facies metamorphism due to the presence of sillimanite. The analysis of garnet revealed significant differences concerning their chemistry. These differences can be interpreted as a I) variscan, a II) permian or a III) permian and Eoalpine imprint. The analysis of dynamic quartz recrystallization shows temperatures between 300C and 400C which presents the weak Eoalpine and Alpine metamorphism. These results suggest the conclusion that the Variscan basement has been affected by a HT/LP metamorphic event during Permotriassic times. Cooling below 300 50C occurred in upper Jurassic and lower Cretaceous times. The Eoalpine and Alpine metamorphism only reached greenschist facies conditions. Brittle structures show the activity of the nearby Periadriatic lineament (PAL) as well as the Labot fault system.