( Sulphide deposits associated to Sardinian Tertiary volcanics. Note I: first results of prospecting in the Perdaxius area, Sardinia).|Mineralizzazioni a solfuri associate alle vulcaniti terziarie della Sardegna Nota I: primi risultati della prospezione dell'area di Perdaxius

The paper reports on the results of recent prospecting for sulphide occurrences related to the Tertiary volcanism in Sardinia. The area concerned was chosen as a test site in order to define the field and laboratory methods to be used in subsequent surveys, owing to its logistical, geological and structural features. Geochemical sampling, both of volcanic rocks and related soils, was carried out over a regular 100 X 100 sqm grid. The spectrophotometric analysis of these samples for base metals revealed anomalous concentrations in certain places and these are investigated in greater depth. The characateristics of the volcanic rocks and of their alterations as well as rocks in the vicinity of contact are investigated by means of microscopic, diffractometric and spectrometric analysis.