The Earth is most rich in diversity and is an active rocky planet in the solar system characterized in existence of the sea, continent, and life, as well as active earthquake, volcanic activity, plate motion and geomagnetic field. Understanding evolution of the Earth and its mechanism also serves as the foundation which replies to the question of "Why is the rich Earth disaster-prone? What is the fundamental reason?" In order to understand this active planet, we investigate a global material-recycling system, including elemental transport and concentration near the surface, subduction of these near-surface materials with down-going plates, subsequent convection within the Earth's interior, and recycle back to the surface of the elements. The elemental recycling is driven by convection of the solid Earth as a thermal engine associated with the "water" which promotes the elemental transport and concentration. These features are investigated by "physicochemical analyses of various materials, including rocks and fluids, in a variety of scales from micro to global, being combined with geophysical observations and numerical simulation. We aim at constructing a comprehensive Earth's image including fundamental understanding of plate motion and material recycling peculiar to the Earth. Such an image will provide a unified explanation and prediction for formation of the internal structure of the Earth by convection, crustal deformation and magmatism, the origin of various rocks and ores exceeding 300 sorts associated with elemental fractionation and concentration which also cherishes life.
Director, Department of Solid Earth Geochemistry