Natural zeolites from Cenozoic pyroclastic flows of Sardinia (Italy): evidences of different minerogenetic processes

Zeolites, mainly clinoptilolite and mordenite, are widespread in northern and central Sardinia, and deposits are distal from the vents. Zeolites form in situ-altered and epiclastic mineralization. The former shows higher zeolite contents than the latter, and zeolitization phenomena pervasively affect the ash-rich and pumice-rich layers. Principally deuteric processes gave rise to phreato-magmatic deposit-types and deposits formed in open hydrologic systems.