S. Faustino di Torri del Benaco (Verona): un esempio di evoluzione geomorfologica per frana di un tratto della Riviera Gardesana

Abstract

On the eastern shore of Lake Garda, near 'Torri del Benaco", there is a large area covered by talus from old landslides which involved the Scaglia Rossa (upper Cretaceous pp) and Biancone (upper Cretaceous pp - lower Cretaceous) Formations. At the conctact between in-situ rock (the Rosso Ammonitico Veronese Fm.) Middle pp to Upper Jurassic) and talus, there is a very fine-grained horizon, a few centimetres thick on average, which contains clasts about 1 cm in size. Where the failure surface is visible, it is always very smooth and displays calcite plates with striae which are parallel to the direction of the maximum slope of the layers, and striae which are subparal-lel to the flow direction of a glacial tongue. Microkarst with corrosion holes is another feature observed on the slope. These elements suggest that the Rosso Ammonitico Veronese and Scaglia Rossa came into contact because of a landslide-controlled geomorphological process rather than a stratigraphic or tectonic gap, as previously hypothesized. Gravity-induced deformations began during Pleistocene, and there is evidence that they continued up to post-glacial times.