The Peron Mount rock avalanche: 36 Cl exposure age dating.

This thesis is a study of a rock avalanche in carbonatic rocks, based on the analysis of the deposits geomorphology and of the triggering, propagation and emplacement phases . The Peron Mount landslide is located in the Belluno Province ,in the north-east Italy. The estimated volume of the landslide deposits is about 108 m3 (Abele, 1972) and 8 x 107 m3 (Cuman, 2006), with a travelled distance of about 4,5 km and a covered area from 19.5 km2. The maximum thickness of the deposit is 40 m (Pellegrini et al., 2006). The age and the overall interpretation of this landslide, was object of debate among the geologists who had studied the deposit for several years. Besides, 14 samples situated in different part of the deposit have been collected to carry out exposure ages datation. The samples have been described, analysed and dated with 36Cl cosmogenic isotope. The method for dating the samples, a procedure based on the AMS (Accelerometer Mass Spectrometry) use, has been described at the end of this thesis. To understand how is the current situation on the Mt. Peron wall, a structural study based on the field fracture analysis has been done. Finally, an interpretation of this large gravitational phenomena was given, taking into account also the present knowledge about rock avalanches.