The bentonite of Iscala Ezza (Ittiri, northwestern Sardinia): ore deposit study and technological characterisation for industry utilisation.

A new bentonite deposit has been discovered in Iscala Ezza. It is hosted by Oligocene-Miocene calc-alkaline volcanites. The mineralisation averages 5 m in thickness and is localised in the upper part of a pyroclastic-cineritic formation about 50 m thick in outcrop. Montmorillonite is the main bentonite mineral with cristobalite, sanidine, quartz and illite as the main accessory minerals. Ematite and goethite occur in the superficial parts of the mineralisation. The main exchangeable cations are Ca and Mg. The origin of the deposit has been proposed as deuteric alteration. This agrees with the observed retention of relict texture by the bentonites. There is also no evidence that weathering and hydrothermal process had significant roles in bentonite formation. The bentonite has good physical and chemical properties for industrial use.
A new bentonite deposit has been discovered in Iscala Ezza. It is hosted by Oligocene-Miocene calc-alkaline volcanites. The mineralisation averages 5 m in thickness and is localised in the upper part of a pyroclastic-cineritic formation about 50 m thick in outcrop. Montmorillonite is the main bentonite mineral with cristobalite, sanidine, quartz and illite as the main accessory minerals. Ematite and goethite occur in the superficial parts of the mineralisation. The main exchangeable cations are Ca and Mg. The origin of the deposit has been proposed as deuteric alteration. This agrees with the observed retention of relict texture by the bentonites. There is also no evidence that weathering and hydrothermal process had significant roles in bentonite formation. The bentonite has good physical and chemical properties for industrial use.