Abstract
Post-nappe brittle structures across the Austroalpine–Penninic wedge are representative of two principal deformation stages. The former (D1) developed during the Late Oligocene, the latter (D2) from the Miocene to the Present. Major D1 features are the E–W Aosta–Ranzola half-graben and the NE–SW Ospizio Sottile subvertical normal fault system. Oligocene extension was also characterized by hydrothermal activity and intrusion of calc-alkaline to ultra-potassic dikes. From the Miocene onwards (D2), the Ospizio Sottile system was re-activated as a SE sinistral boundary of the Pennine–Graian Alps block of nappes, bodily moving away from the Simplon detachment to the SW. Inside the escaping block, a number of D2 slightly diverging sublatitudinal splays (Aosta–Piccolo San Bernardo system) was generated, as well as a regular set of NW-trending normal faults from the Simplon to the Gran Paradiso massif. Instead, the Aosta–Ranzola system was poorly reworked in that time. More generally, the short-lived Oligocene extension (D1) was associated to slab break-off of lower plate, wedge rebound, rapid uplift and thermal perturbation. From the Early Miocene onwards the Oligocene extension was replaced by renewed compression, allowing the vertical extrusion of the Lepontine dome and lateral escape of the overlying Pennine–Graian Alps block.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.