The main research interest is to understand the role of magma in the evolution of the earth. Recent studies have revealed that material injected by subduction played important role on magmatism at various locations. For example, subducted oceanic crust recycles at the surface as hot spot volcanism and continental flood basalts, and the connectivity of aqueous fluid released from subducted slab controls the location of volcanic front in island arcs.Research is mainly based on experiments, chemical analysis, and numerical modeling. Experiments at high pressures and temperatures are made to determine the phase equilibrium, solid-melt element partitioning, and physical properties of magma such as element diffusivity within both volatile-bearing and volatile-free systems. Melting phase relations of tholeiitic basalt studied at high pressures provide fundamental information to discuss the fate of subducted oceanic crust in the mantle. Numerical methods are developed for assessing the possibility of involvement of ancient subdcuted oceanic crust into plumes from deep in the mantle, and a model for extensive basaltic volcanism has been proposed. The physico-chemical properties of aqueous fluid are also studied at high pressure because it controls not only the genesis of magmas but also the eruptive processes of magmas at volcanoes. Works on melt inclusions trapped in phenocrysts are going on in order to constrain chemical evolution of magma chamber, P-T path of magma ascent, and degassing processes.
1. A. Yasuda, A new technique using FT-IR micro-reflectance spectroscopy for measurement of water concentrations in melt inclusions , EPS, 66, DOI: 10.1186/1880-5981-66-34, 2014