Disentangling the stratigraphic architecture of the Rivoli-Avigliana end moraine system (Western Alps, NW Italy)

Abstract

The Rivoli-Avigliana end moraine system (Italian Western Alps) hosts an important stratigraphic archive of Pleistocene glaciations. A new geological map provides a 3D architecture of the system that reveals a complex architecture of glacial, alluvial and lacustrine units. Six glacial units were recognized. During the deposition of the four older glacial units (Early-Middle Pleistocene) the morphology of the valley outlet had a different drainage pattern from the present, with the presence of large lakes. From the penultimate glaciation to the Last Glacial Maximum (LGM) the piedmont lobe was confined within the valley, never extending towards the alluvial Po Plain. The LGM is characterized by two glacial advances and four distinct recessional phases during the Lateglacial. The presence of a bedrock inselberg affected the flow of the glacier front, which should have had weak erosive strength as shown by the preservation of lacustrine deposits below the glacial units.