Mineralization and Skarn Formation Associated with Alkaline Magma Chambers Emplaced in a Limestone Basement: A Review

The emplacement of shallow magma chambers within a carbonate basement is a typical feature of many volcanic systems around the world. The accompanying formation of exoskarns, endoskarns, cumulates, exsolved fluids and differentiated melts at the interface between the magma chamber and carbonate host-rock is well documented through mineralogical and geochemical studies of ejected skarns and cumulates and through fluid and melt inclusion studies. This review presents the current knowledge on the interaction of alkaline magma chambers with carbonate-bearing host-rocks, with a focus on the geochemical evolution and mineralization at the outer margins of the magma chamber and the accessory mineral phases at Somma-Vesuvius, Colli Albani and Merapi volcanic systems. Furthermore, we discuss how this interaction and its products, especially the CO2 released during the thermometamorphic decarbonation of the carbonate host-rock, impacts the eruptive behavior in all three systems.