Metasomatism by Boron-Rich Fluids along Permian Low-Angle Normal Faults (Central Southern Alps, N Italy)

Low-Angle Normal Faults (LANFs) represent in the central Southern Alps area (N Italy) main structures along which Variscan basement is contact with Upper Carboniferous-Permian volcanic-sedimentary succession. Tourmalinites frequently occur LANFs, usually replacing former cataclasites. The mineralogy and chemical composition of tourmalinites point to a metasomatic origin. together high-angle faults, controlled opening Permian Orobic Basin likely acted as preferred pathway for hydrothermal fluids that triggered Boron-metasomatism. Along Aga-Vedello LANF, appear have formed after cessation fault activity, no brittle post-metasomatism deformation overprint has been observed. These relationships suggest circulation B-rich occurred broadly constrained Early Permian. At same time, ca. 285–270 Ma, strong magmatic activity affected all Alps, ranging from mafic acidic rocks intrusions at deep crustal levels effusive volcanic products. magmatism was source late-stage tourmalinites. could also played significant role formation Uranium ore deposit Novazza-Vedello mining district, bodies Vedello valley are concentrated basement-cover contact.