I depositi di caolino associati al vulcanismo calc-alcalino oligo-miocenico della Sardegna. Caratteristiche geogiacimentologiche, geochimiche e prospettive tecnico-economiche.

The work is aimed at defining the economic potential of the kaolin deposits of Sardinia. Three main districts were investigated: Romana, Tresnuraghes and Serrenti-Furtei. The kaolin deposits occur in the Oligocene-Miocene calc-alkaline volcanic series of Sardinia: geological and geochemical evidences support the hydrothermal origin for all investigated districts. The alteration phenomena are everywhere associated to faults and fractures, where fluid circulation started and enhanced the kaolinization processes. Samples from several deposits were studied by XRD and XRF methodologies. The results confirm similar chemical and mineralogical feature for the kaolin of Romana and Tresnuraghes. At Serrenti-Furtei, the kaolin has higher content of alumina than the other deposits. Standard calculation were performed on the samples to determine the kaolinite contents in the rocks with a view to their possible industrial uses.