Phlogopite and coesite exsolution from super-silicic clinopyroxene

Yongfeng Zhu, Yoshihide Ogasawara

    Research output: Contribution to journalArticle

    60 Citations (Scopus)

    Abstract

    We document the exsolution of phlogopite and coesite/quartz from pre-existing super-silicic clinopyroxene in dolomite marble from the Kokchelav massif, northern Kazakhstan. The exsolution texture was formed by clinopyroxene decomposition through the reaction (3enstatite + 2KAlSi2O6)epx = phlogopite + 4coesite. Phlogopite exsolution must have occurred at pressures less than 8.0 GPa (at 1000°C). where the garnet + super-silicic clinopyroxene + phlogopite assemblage was stable, based on experimentally defined phase relations. Observations described in this report suggest that the precursor clinopyroxene was stable at pressures higher than 8 GPa (>1000°C), implying that the dolomite marble was subducted to mantle depths greater than 240 km. Such profound subduction could be an important mechanism to transport abundant H2O and potassium into the deep Earth.

    Original languageEnglish
    Pages (from-to)831-836
    Number of pages6
    JournalInternational Geology Review
    Volume44
    Issue number9
    Publication statusPublished - 2002 Sep

    Fingerprint

    coesite
    exsolution
    phlogopite
    clinopyroxene
    marble
    dolomite
    garnet
    subduction
    potassium
    texture
    decomposition
    quartz
    mantle

    ASJC Scopus subject areas

    • Geology

    Cite this

    Phlogopite and coesite exsolution from super-silicic clinopyroxene. / Zhu, Yongfeng; Ogasawara, Yoshihide.

    In: International Geology Review, Vol. 44, No. 9, 09.2002, p. 831-836.

    Research output: Contribution to journalArticle

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