Segnalazione di una «paleofrana» in Val Chisone presso Fenestrelle (Provincia di Torino)

Report of a ” paleolandslide” in the Valle Chisone near Fenestrelle (Province of Turin)

Abstract

The presence of the considerably remodeled remains of an ancient landslide is reported. The accumulation body consists of large, angular blocks of « schistes lustrées » and prasinites immersed in a fine matrix and now covers an area of about 5 km² , with a thickness of over 100 m. It is composed of two flanking bodies on the left side of the valley, with two distinct detachment niches below them. The frontal part climbs some way up the other side of the valley. Formation of the heap led to damming up of the valley and the establishment of an extensive lake basin immediately upstream. Its deposits are now completely buried by more recent deposits. The location of the waste in a valley cutting modelled by the Würmian glacier shows it to be post-Würmian. In addition, its marked etching by watercourses suggests it’s not being recent. Examination of the recent tectonic features of the area has made it clear that the mass movements have among their causes the activity of the important Cenischia-Nice fracture system.