Magma genesis and metasomatism

Several authors ascertained the significant role of metasomatic enrichment processes for generating mineralogical and chemical heterogeneity in the mantle.

Such an occurrence can be strictly localized, originating small- to intermediate-scale heterogeneity in the upper mantle, but if large volumes of fluids or melts migrate, vast regions of the mantle can be affected by metasomatism, leading to large-scale lithologic heterogeneity. These processes are mainly ruled by the migration of LILE- and LREE-carrying fluids or silicate melts, which permeate and vein the pre-existing mantle.  

    Interactions between anhydrous or poorly hydrated host mantle rocks and the migrating fluids/melts may then stabilize hydrous mineral phases, such as amphibole and/or phlogopite, depending on the influx composition as well as on the depth at which reactions occur. Partial melting processes are then able to produce a wide spectrum of melt compositions, depending on the mantle portions tapped.

      The understanding of the intrinsic characteristics of the source becomes therefore a crucial factor in order to understand which are the features that magmas inherited directly where they formed. We dedicate efforts in this research field, focusing primarily the attention to Mt. Etna volcano. Specifically, we investigate the complex effects that chemical mantle heterogeneity can induce in generating short-term changes of trace element geochemistry and Sr-Nd-Pb-Hf-O isotope  compositions of volcanic products at the surface, providing clues to interpret its role in controlling the melting mechanisms, magma production, emission rates and eruptive behaviour.