The Alpe Laghetto Mines

The nickel mines are situated on the southern slopes of Monte Capio, between Val Sabbiola and Valbella, both of which are side valleys of Val Mastallone. Nickel mineralisation is characteristic of the Ivrea-Verbano Formation, a basic and ultrabasic complex associated with the upwelling of mantle material. This section of the Palaeo-African continental crust is now visible at the surface thanks to movements associated with Alpine orogenesis, which rotated the entire crust by 90°. The entire basic complex is generally divided into five parts, four of which contain nickel mineralisation.

The area known as ‘Monte Capio-La Balma’ is characterised by a flattened body of basic and ultrabasic igneous rocks embedded within metamorphosed sediments belonging to the Kinzigiti Series. The basic body is in contact with the surrounding metasediments, whose metamorphic event coincides with the intrusion itself; this is referred to as contact metamorphism. The intrusion consists of a thin layer of peridotites surrounded by even thinner layers of pyroxenites and gabbros. The main nickel mineralisation is located at the base and summit of the peridotite unit, where minerals such as pyrrhotite, pentlandite and chalcopyrite are found. Unlike other deposits in the Ivrea-Verbano area, no platinum-bearing minerals are present here.

The Alpe Laghetto peat bog is situated on a natural counter-slope, likely a basin formed by over-excavation caused by glacial action. As the ice melted, this basin filled with water, hence the name Alpe Laghetto. The peat bog is simply the natural evolution of the former lake, as it does not receive sufficient water inflow and is slowly being filled with sediment from Mount Capio.

In the 1950s, palynological research was carried out on this peat bog, leading to the discovery that species not found at this altitude today – such as Abies, Picea, Pinus, Quercus, Ulmus and Tilius – had once existed in the area, probably during an intraglacial period.