地球化学的解析から見たスラブ起源流体：天然の岩石化学組成と高圧実験からの制約

抄録

  The slab-derived fluid (slab-fluid) liberated from subducted materials, such as sediments and altered oceanic crust (AOC) in the subducting plate, is in general abundant in hydrophile elements. Many geological features occurred in subduction zones such as volcanism, earthquake, diastrophism and metamorphism are thought to be affected by the contribution of slab-fluid. The physical and chemical properties of slab-fluid depend on the compositions of AOC and sediment consisting of the subducting oceanic plate, and the condition of pressure, temperature and mobility of elements where the slab-fluid is generated. In this article, I overview how trace element and isotopic ratio are constrained on the basis of the compositions of volcanic rocks and the high-pressure experiments on element mobility, then estimate the geochemical characters of slab-fluid and hydrous mantle involving magma genesis beneath the Japan arcs as an example.