Figure 6.

The differences in water contents between arc and hotspot melts may lead to fundamental differences in the form and extent of the magma reservoirs in these settings. Magmatic systems in arc settings will generate larger fractions of exsolved volatiles; and will undergo degassing-induced crystallization at greater depths in the crust [139], which promotes the generation of crystal mushes. Olivine melt inclusion concentrations of H₂O and CO₂, for a range of ocean island volcanic products. The bottom plot is a zoomed in portion of the top plot. Isobars, labelled with pressure in MPa, are shown, appropriate for basalt [199]. Data for Fernandina and Santiago from [200]; for Kīlauea from [54], for El Hierro from [201] for Laki [90], for Holuhraun [86], for Stromboli [202], for Etna [203] for Llaima [204,205] and for Fuego [206–209].