Borgone Roches Moutonèe GEOSITE

Title

Description

The rocky buttresses that rise in steps behind the town of Borgone represent one of the best-preserved examples of the powerful modelling and smoothing action exerted by the great quaternary glacier of the Susa Valley.
These spurs present a markedly rounded top, with the flanks south-facing sides steep and smooth, while those exposed to the north connect to fertile plateaus, often elongated according to the direction of the valley axis.
Remaining intact for thousands of years, this evidence of glacial modelling has been eroded in several places by the opening of quarries for the exploitation of the valuable Borgone meta granite. The mining activity, carried out intensively for centuries, has given the landscape a new architecture not without its own interesting features.

Borgone's metagranite has long been a primary source of wealth for the local economy. The open quarries on the mountain ridges of the left slope provided blocks of valuable material from which skilled stonemasons ('picapere') extracted lintels, windowsills, columns, capitals, and ashlars used for monuments, palaces, bridges, etc.
This flourishing activity ceased in the 1970s with the closure of the large Chiampano quarry, which has now been transformed into a popular rock gymnasium exploiting roofs and ledges developed in the schistosity planes and fracturing systems.
No less important in the Borgone area was the cultivation of softer levels rich in lamellar minerals (mica) for the production of millstones (or grindstones). This singular activity came to an end before the 20th century and was mainly concentrated in correspondence with a rocky buttress not far from the Chiampano settlement, called 'Roccafurà'; a local term evocative of the large fissure opened in the belly of the mountain. Exploitation took place at the expense of lenticular bodies of silvery micaschists embedded in metagranite and strongly deformed, with thicknesses varying from a few decimeters to a few metres.

Geosite element

Borgone Metagranite

Borgone Roches Moutonée

Lithology

orthogneiss

mica schist

Landform shape

Roche Mountonnee

Event environment

glacier related setting

Event process

erosion

Older named age

Pleistocene

Interest

Geomorphological

Geomining

Item