Metalliferous and industrial materials mineralisation in the Monastir-Furtei district: illustrative note to the geological and georesource map of the volcanic district of Monastir-Furtei (southern Campidano, Sardinia).

The volcanic rocks of the Tertiary calc-alkaline cycle have undergone late-stage hydrothermal alteration which has given rise to a variety of mineralisation, in a zone bounded to the east by the Miocene cover and to the west by the Campidano graben. Two main areas of kaolin deposits, consisting mainly of kaolinite with some montmorillonite and dickite, are centred on Monte Porceddu and Coronas Arrubias, but the silica and pyrite content limits current extraction to the production of aluminous refractories. Metalliferous mineralisation is concentrated almost exclusively in the area of maximum argillic alteration, intense silicification and pyritisation. Exploration is in progress of two gold deposits at Monte Santu Miali and others at Is Concas and Sa Perrina. Mineralisation at Santu Miali and Is Concas is rich in As, with the main minerals pyrite, enargite-luzonite, tennantite, covellite, chalcopyrite, digenite and sphalerite; the native gold is almost pure (1-2% Ag), in micrometre-scale granules in enargite and luzonite. At Sa Perrina the visible mineralisation is disseminated pyrite with some chalcopyrite and local, rare wurtzite, sphalerite, galena, covellite and digenite. The gold, though not visible, must be in a sufficiently native and free state to have responded satisfactorily to processing. Other resources are rock products including inert materials, construction stone, dimension stone and industrial materials such as cement.
The volcanic rocks of the Tertiary calc-alkaline cycle have undergone late-stage hydrothermal alteration which has given rise to a variety of mineralisation, in a zone bounded to the east by the Miocene cover and to the west by the Campidano graben. Two main areas of kaolin deposits, consisting mainly of kaolinite with some montmorillonite and dickite, are centred on Monte Porceddu and Coronas Arrubias, but the silica and pyrite content limits current extraction to the production of aluminous refractories. Metalliferous mineralisation is concentrated almost exclusively in the area of maximum argillic alteration, intense silicification and pyritisation. Exploration is in progress of two gold deposits at Monte Santu Miali and others at Is Concas and Sa Perrina. Mineralisation at Santu Miali and Is Concas is rich in As, with the main minerals pyrite, enargite-luzonite, tennantite, covellite, chalcopyrite, digenite and sphalerite; the native gold is almost pure (1-2% Ag), in micrometre-scale granules in enargite and luzonite. At Sa Perrina the visible mineralisation is disseminated pyrite with some chalcopyrite and local, rare wurtzite, sphalerite, galena, covellite and digenite. The gold, though not visible, must be in a sufficiently native and free state to have responded satisfactorily to processing. Other resources are rock products including inert materials, construction stone, dimension stone and industrial materials such as cement.