Deep-seated gravitational slope deformation involving glacial evidence in the Rodoretto Valley (NW Alps)

Abstract

The Rodoretto Valley (about 25 km2) (Western Alps, NW Italy) shaped in the metamorphic bedrock, covered by Quaternary sediments, is involved in significant deep-seated gravitational slope deformation (DSGSD). A detailed field survey revealed several morpho-structures typically related to DSGSD phenomena (open fractures, doubled ridges, scarps, trenches, counterscarps and bulging reliefs) and other significant gravitational morphologies, here defined as gravitational valleys, not previously reported in geological literature.Fieldwork also allowed us to distinguish various types of glacial sediments, reconstructing the supply basins, relatively dating glacialism to LGM and Late Glacial-Holocene and evaluating their gravitational dislocation. The wide extension of the area characterized by DSGSD and incredibly big dimension of single morpho-structures are the most important recognized features. In particular, we observed that entire sectors of the study area were gravitatively conditioned not only by local slid along the Rodoretto slopes but also by movement towards the nearby and deeper Germanasca Valley.

Keywords

• deep seated gravitational slope deformation
• glacial shaping
• quaternary
• alpine geomorphology
• germanasca valley