The Volcanic and Mining Geoheritage of San Pietro Island (Sulcis, Sardinia, Italy): the Potential for Geosite Valorization

Spectacular volcanic landforms characterize the Miocene lava flows and ignimbrites forming San Pietro Island (Sardinia, Italy). The island, furthermore, is a site of volcanic-hosted manganese mineralizations, which have been exploited until the past century. These geological features, set in a fascinating landscape context, represent a volcanic and mining geoheritage which could be valorized in terms of sustainable geotourism and scientific outreach. In this paper, we examine potential sites of volcanological and mining geoheritage interest of San Pietro Island, some of which are part of the Italian Geosite Inventory. We update the scientific description of geological features according to the most recent research results, because we consider that a geosite description should evolve along with the development of scientific understanding. Also, we present some new potential geosites, with a discussion of their scientific relevance and geotouristic potential. Three geo-volcanological features are identified: the spectacular megafolding structures of the comenditic lava flows, some peculiar and uncommon degassing features of ignimbrites, and the volcanic-hosted manganese mineralizations and the related mining heritage. Based on this, four geosites are proposed and described: Becco Nasca (lava flow folding), Cala Fico (lava flow folding and mining heritage), La Punta (degassing features of ignimbrites), and La Piramide (mining heritage). Some actions are suggested to promote the valorization of the geological and mining features of these geosites for geotourism and scientific outreach, and to raise awareness of these geoheritage values among the general public.