Modellazione 3D dell’architettura di zone di faglia nel settore orientale del Lineamento Periadriatico.

The E-W Pusteria (Pustertal) line is the eastern segment of the Periadriatic lineament, the >600 km tectonic boundary between the Europe and Adria-vergent portions of the Alpine Collisional Orogen. The crustal-scale Periadriatic lineament is characterized by a transcurrent polyphase activity of Tertiary age, and is marked by an array of calcalkaline to shoshonitic magmatic bodies. The western edge of the Pusteria line is marked by the Mules tonalitic lamella and represents the tectonic divide between the Austroalpine paragneiss and the Brixen granitoid. The Pusteria line, in turn, is cut by the later Sprechenstein-Mules fault, actually the kinematic linkage between the Pusteria system and the extensional Brenner detachment during the Miocene-onward lateral extrusion of the Tauern window block towards the E. At the map scale, this line is characterized by a complex network of dextral brittle fault zones, interconnected by transpressional step-overs. A 3D geological model of fault architecture, in which damage zones are classified according to fracture density and fault cores according to fault rock typologies, has been reconstructed from borehole data and a detailed 1:5000 geological map. The model highlights a first order relationship between lithology and the degree of fracturing in damage zones. In addition, highly-damaged lobes appear to be centred on contractional stepovers, whilst rectilinear fault segments are associated to thinner damage zones.