Zeolites as Tools for Interpreting Geological and Geochemical Conditions

Natural zeolites typically form in low-temperature (<200 °C) environments under alkaline conditions (pH > 8). Their formation generally follows a thermal–chemical gradient, which often results in a zonation pattern of zeolites and other alteration minerals that can be linked to the physicochemical conditions existing during formation. Careful investigation of mineral compositions, sequences, and patterns at different scales facilitates unraveling past fluid–rock interactions. Investigations of the time-dependent alteration and formation of zeolites in young volcanic tephra deposits allow for a better understanding of the variability of zeolite mineralogy with respect to the effects of temperature, fluid chemistry, hydrological conditions, and time.