Mon. May 21, 2018 1:45 PM - 3:15 PM Poster Hall (International Exhibition Hall7, Makuhari Messe)

convener:Yoshihiko Tamura(R & D Center for Ocean Drilling Science, Japan Agency for Maine-Earth Science and Technology), Osamu Ishizuka(Geological Survey of Japan, AIST), Chris Conway

A paradigm of the solid Earth geochemical cycles is that the Earth's crust forms by melting of the Earth's upper peridotitic mantle. A new study relates crustal thickness to magma type in the Izu-Ogasawara (Bonin) and Aleutian oceanic arcs, which suggests that continental crust (andesitic magma) is produced only when the crust is thin, thus only in oceanic arcs. How diverse is the spectrum of primary melts and which factors may contribute to its variations? What is the influence of crustal processing vs. primary magma diversity in creating the diversity of the Earth's crust? The session seeks to explore the crust-mantle connections among ophiolites, at divergent and convergent plate boundaries and within-plate (or ocean island??) settings based on volcanology, petrology, geochemistry, geophysics, geochronology, and geodynamics studies.