Morphological stability of hydrous liquid droplets at grain boundaries of eclogite minerals in the deep upper mantle

• MATSUKAGE Kyoko N.

  Earth and Planetary Sciences, Tokyo Institute of Technology Present address: Center for Fundamental Education, Teikyo University of Science

• HASHIMOTO Mika

  Geodynamics Research Center, Ehime University

• NISHIHARA Yu

  Geodynamics Research Center, Ehime University

抄録

The morphological stability of hydrous liquid droplets at grain boundaries of eclogite minerals in the basaltic part of a subducting slab were investigated based on experimental constraints for the dihedral angles. We measured the dihedral angles in the eclogite–H₂O system at a temperature of 1000 °C and at pressures ranging from 4 to 16 GPa. The dihedral angle of hydrous liquid versus garnet–garnet (θ_GG–L) increased with increasing pressure from 46° at 4 GPa to 66° at 12 GPa, although it showed a weak decreasing trend at pressures higher than 12 GPa. The dihedral angle of hydrous liquid versus clinopyroxene–clinopyroxene (θ_CC–L) was almost constant with increasing pressure (61 and 59° at 4 and 10 GPa, respectively). The dihedral angle of hydrous liquid versus garnet–clinopyroxene (θ_GC–L) was 73–76° at 4–10 GPa, and it was always higher than θ_GG–L and θ_CC–L. By applying the morphological stability criteria for liquid in a system with two solid phases (garnet and clinopyroxene) and bond percolation theory for a three–dimensional lattice of tetracoordination, we found that the hydrous liquid was isolated at the grain edges and corners of eclogite minerals in the cold slab under a wide range of pressure conditions of the upper mantle from 4–14 GPa when the grain size of garnet was equal to that of clinopyroxene. Thus, basaltic crust containing hydrous liquid droplets may carry water to the lowermost upper mantle and the mantle transition zone when the slab is cold.

収録刊行物

• Journal of Mineralogical and Petrological Sciences

  Journal of Mineralogical and Petrological Sciences 112 (6), 346-358, 2017

  一般社団法人　日本鉱物科学会

キーワード

• Dihedral angle
• Eclogite
• Subducting slab
• Water
• Hydrous liquid

詳細情報

• CRID: 1390001206546109568
• NII論文ID: 130006287887
• DOI: 10.2465/jmps.170309
• ISSN: 13493825
• ISSN: 13456296
• Web Site: https://www.jstage.jst.go.jp/article/jmps/112/6/112_170309/_pdf
• 本文言語コード: en
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