Complete wetting of olivine grain boundaries by a hydrous melt near the mantle transition zone

Takashi Yoshino, Yu Nishihara, Shun ichiro Karato

    Research output: Contribution to journalArticlepeer-review

    61 Citations (Scopus)

    Abstract

    Many physical properties of liquid-bearing rocks in the deep Earth's interior are strongly controlled by its wetting behavior. We report experimental results on the variation of dihedral angle and microstructures in the forsterite-H2O system at 1200 °C and pressures ranging from 1 to 13 GPa. The dihedral angle of the system decreases systematically with pressure and above the mantle transition zone (∼ 400 km depth) it becomes approximately 0°, corresponding to completely wetted grain boundaries. This condition is probably reached because of a decrease in the solid-liquid interfacial energy with pressure due to the dramatically increased solubility of silicates in the liquid. These results suggest that the presence of partial melt would have drastic influences on physical properties of upper mantle around the transition zone even if the melt fraction is very low. Low velocity regions just above the mantle transition zone may result from the presence of hydrous melt.

    Original languageEnglish
    Pages (from-to)466-472
    Number of pages7
    JournalEarth and Planetary Science Letters
    Volume256
    Issue number3-4
    DOIs
    Publication statusPublished - Apr 30 2007

    Keywords

    • dihedral angle
    • grain boundary
    • olivine
    • transition zone
    • upper mantle
    • water
    • wetting property

    ASJC Scopus subject areas

    • Geophysics
    • Geochemistry and Petrology
    • Earth and Planetary Sciences (miscellaneous)
    • Space and Planetary Science

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