ABSTRACT

High pressure experiments up to 4.0GPa on natural serpentinite, one of constituent members of the hydrated subducted oceanic lithosphere, show that it decomposes totally at temperatures below 700°C. The results suggest that the serpentinite-derived aqueous fluid can be supplied to the mantle wedge only beneath the fore-arc region. The concentration of Rb, Sr and Yb in the aqueous fluid released through the dehydration process of serpentinite are estimated on the basis of open-system dehydration experiments under 1.5 and 3.0GPa, in which the fluid is lost through perforations on a gold sample container; the aqueous fluid transports a larger amount of an element with a larger ionic radius under higher pressures.