Geologia del Quaternario del Monte Berlinghera e del Pizzo Sasso Canale (Provincia di Como)

Abstract

Three Quaternary units, two of which belonging to the last glacial Episode while one is postglacial, can be observed between Monte Berlingherà and Pizzo Sasso Canale in the western sector of Upper Lario. Some morphologic features suggest the existence of a glacial activity that occurred before the last Episode. The Pian del Tivano Formation (Upper Pleistocene), where the deposits can be observed from the lake level up to 1680 m, has been correlated with the Cantú Drift described by Bini (1987) in the Como area. From the lithological analysis of the erratics the area of provenance of the glaciers has been inferred as well as it has been evaluated the influence of these latter on the depositional pattern in the studied area. The most abundant lithotypes come from Val Chiavenna. Provenance from Valtellina is subordinate. The Prato Fortunato Formation (Upper Pleistocene-Holocene ?) is to be connected with the activity of the glacier set in the glacial cirque SE of Pizzo Sasso Canale. It is not possible to correlate these deposits with the ones of the Pian del Tivano Formation in that a direct contact between the two units has not been observed. The postglacial Unit (Holocene) comprises all the deposits which are subsequent to the final retreat of the glaciers in the area. Besides a strong activity along the slopes, evidence of lacustrine deposits 10 m higher than the present level of the lake have been observed.