Base metal enrichment in volcanic sublimates and secondary alteration products from Vesuvius and Vulcano

A wide range of volcanic sublimates and alteration products from the Johnston-Lavis collection z has been analysed for major elements plus copper, lead, and zinc. 'Aphthitalite' and 'natrikalite' from Mount Vesuvius and an 'alum' from the island of Vulcano all proved to be enriched in copper and selected analyses are tabulated. The process leading to copper and lead enrichment of the Vesuvian material may be vapour phase transport as chloride followed by sulphation on sublimation. It is suggested that the source of the copper found in the alum sample from Vulcano could be of interest to economic geologists.