Petrological and geochronological investigations on the individual nappes of the Meran-Mauls nappe stack (Austroalpine unit/South Tyrol, Italy)

Abstract The Meran-Mauls nappe stack is part of the Austroalpine unit in South Tyrol (Italy). There it holds a special position directly front Southalpine Dolomites indenter and west Tauern Window. It situated hanging wall unit, above NW dipping segment Periadriatic fault system, namely fault. Also all other sides are defined by Oligocene-Miocene strike-slip normal faults. Based on recent mapping consists three nappes separated to NNW shear zones. lowermost southwest represented Schenna (Scena) unit. overlain along Masul zone consisting Hirzer (Punta Cervina) Pens (Pennes) including Triassic (meta)sediments. Separated Fartleis St. Leonhard (San Leonardo) forms uppermost nappe. aim this study describe individual units separating structural elements more properly, based new structural, petrological, geothermobarometric geochronological data compare these vicinity. Sillimanite-bearing paragneiss, minor amphibolite quartzite as well distinct marble layer close its base characterise Further, contains pegmatite dikes, presumably Permian age. Amphibolite-facies P-T conditions c. 0.55 ± 0.15 GPa 600 100°C thus correlated with metamorphic imprint. mostly mylonitic paragneiss pre-Alpine age probably formed during Jurassic. For upper greenschist- amphibolite-facies 0.4-0.50 550 70°C attributed Variscan tectonometamorphic whole represents zone. Due occurrence Permotriassic (meta)-sediments within zone, an Alpine structure, bordering Rb/Sr biotite ages yield sometimes partly reset values stack, indicating pervasive anchizonal greenschist-facies overprint Eoalpine event. Tectonostratigraphically can be Drauzug-Gurktal system. latter element only shows weak overprint. With respect lithologic composition Tonale Strieden-Komplex east.