地球化学的数値実験によるマグマの形成・移動メカニズムの研究  [in Japanese] Geochemical studies on magma generation and migration with numerical modeling  [in Japanese]

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Author(s)

    • 岩森 光 IWAMORI Hikaru
    • 名古屋大学大学院理学研究科地球惑星理学専攻: (現)東京大学大学院理学系研究科地質学専攻 Department of Earth and Planetary Sciences, Nagoya University: (Present address) Geological Institute, University of Tokyo

Abstract

Studies on the processes of magma generation and migration are reviewed, with special reference to geochemical and numerical modeling. A full set of governing equations for describing melting and melt migration by porous flow are introduced, in which the relationships between the equations (conservation of mass, momentum and energy) and the variables are investigated. Based on the governing equations, characteristics of the melt-solid flow systems with chemical reactions are described, which shows that the chemistry of the melt and solid can be used to investigate the processes involved quantitatively (e. g., the style of melt migration). Application of these theories and numerical modeling to the magmatism at mid-ocean ridges revealed that more than 80 per cent of the melt produced beneath the ridges is transported towards the surface without significant chemical reaction on ascent within a short period of time (e. g., less than 1,000 years). Magmatism and metamorphism in subduction zones are also modeled, which suggests that transportation of H<sub>2</sub>O and melting depend strongly on the age of the subducting slab. Associated with subduction of young (<10 m. y.) slabs and ridges, transition in terms of magmatism and metamorphism occurs within 10 m. y., from (1) normal arc melting in mantle wedge, (2) forearc mantle melting (high-Mg andesitic) to (3) slab melting in which a significant amount (〜100 km<sup>3</sup>) of granitic melt is produced. The model results newly show that, this event of ridge subduction should cause synchronous formation of granitic batholith by slab melting and regional paired-metamorphic belts, such as Ryoke-Sanbagawa belt in Japan. These results show that the geochemical and numerical modeling is a useful approach in order to understand the melt generation and migration processes and their roles in the Earth's history.

Journal

  • Chikyukagaku

    Chikyukagaku 33(3), 155-175, 1999

    The Geochemical Society of Japan

References:  71

Cited by:  2

Codes

  • NII Article ID (NAID)
    110008679980
  • NII NACSIS-CAT ID (NCID)
    AN00141280
  • Text Lang
    JPN
  • Article Type
    Journal Article
  • ISSN
    0386-4073
  • NDL Article ID
    4839970
  • NDL Source Classification
    ZM41(科学技術--地球科学)
  • NDL Call No.
    Z15-645
  • Data Source
    CJP  CJPref  NDL  NII-ELS  J-STAGE 
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