Olivine Melt Inclusion Constraints on Some Intensive Properties of Subvolcanic Crystal Mushes and Their Evolution through Boundary Layer Fractionation in Northern Japan

Abstract Magma differentiation in arc settings has usually been attributed to an interplay of processes (fractional crystallization, assimilation, and magma mixing). Homogeneous fractional crystallization widely used model the magmatic evolution volcanic systems due its simplicity, even though boundary layer fractionation (BLF) proposed as a preponderant process hydrous systems. Both models produce distinct compositional paths application wrong yields erroneous estimates parameters like pressure–temperature-H2O conditions primary melt compositions. Melt inclusion (MI) populations corrected for post-entrapment have potential help discriminate between these two types their compositions are not affected by crystal accumulation should capture occurs. In this study, olivine-hosted MIs assess trends basic magmas northern Japan. Differentiation from five Japan show that BLF is ubiquitous. unable explain liquid lines descent minor elements, TiO2 P2O5. To reproduce trends, presence accessory phases titanomagnetite or apatite required, which many cases equilibrated need be fractionated amounts incompatible with homogeneous fractionation. The prevalence all studied indicates solidification fronts key environments crustal some subduction zone magmas.