The Texel-Schneeberg boundary in the Pfossen valley (Merano, NE Italy): geological-structural map and explanatory notes

Abstract

The Schneeberg Complex (Merano, NE Italy) was traditionally distinguished from the surrounding Austroalpine basement on the base of its peculiar lithological association made of garnet-rich metapelites, calc-schists, paragonite amphibolites and garnet-amphibole schists, locally with megablasts of garnet and amphibole. As the Schneeberg Complex is considered to be a monometamorphic unit with Alpine metamorphism only, its southern boundary with the polymetemorphic Texel Complex is a key-element in deciphering the tectono-metamorphic evolution of the Austroalpine basement in the western sector of the Eastern Alps. On the base of the field structural analyses the two units display a common structural evolution at least from the Alpine amphibolite facies event (D2 in our reconstruction). In the upper Pfossen valley the marbles, amphibolites and garnet mica schists succession forming the external part of the Schneeberg Complex are folded together with the Texel metapelites in tight structures with step axes, known as «Schlingen» folds. These peculiar structures are due to the D2-D3 folds interference pattern. The results of the structural analysis in the study area are almost coherent with recent interpretations that propose the entire Schneeberg Complex to represent a greenschist facies crustal scale shear zone (SNFZ, Schneeberg Normal Fault Zone) along which the Texel Complex, containing rocks with eclogitic relics of Alpine age, have been exhumed with a SE direction, starting from the late Cretaceous times