Campertogno

In the Campertogno area, it is possible to observe erosional features and deposits associated with river and glacial activity.

The plateau on which the hamlet of Tetti is built is, in fact, an alluvial terrace – a gently sloping surface formed by successive floods of the River Sesia (the area hatched in light blue in the image). River terraces generally represent ancient sections of the river bed, abandoned following a phase of erosion that caused the river channel to deepen. The river terrace here is also ‘contaminated’ by debris from the right-hand bank, which alternates with the alluvial material. This phenomenon is clearly visible in the erosion scarp to the south of the bridge over the Sesia.

The hamlet of Argnaccia, on the other hand, which lies above Campertogno and is separated from the valley floor by a rock face with a cliff face over 300 metres high, is situated on a glacial terrace (the area marked in grey in the image), a relict of past glaciation. It is, in fact, the ancient valley floor, eroded by the retreat of the glacier itself or by subsequent, smaller glaciers, and finally by the action of the river.