Phase equilibria and mineral parageneses of metabasites in low- grade metamorphism.

J. G. Liou, S. Maruyama, M. Cho

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    219 Citations (Scopus)

    Abstract

    The system CaO-Al2O3-Na2O-MgO-SiO2-H2O is suitable for modelling phase equilibria and mineral parageneses for low-T metamorphism of basaltic rocks; univariant reactions marking the transitions between various sub-greenschist facies are identified and some have been determined experimentally. The introduction of Fe2O3 into a model of fixed FeO/MgO ratio creates continuous reactions for facies boundaries and discontinuous reactions for invariant points. The XFe3+ isopleths for epidote are plotted to illustrate the transition from the zeolite facies, through prehnite-pumpellyite to the prehnite-actinolite facies, and T-XFe3+ relations are established for both continuous and discontinuous reactions relating such facies transitions. An isobaric Al-Ca-Fe3+ plot from the chlorite projection can be applied to low-T metamorphic rocks where two or three Ca-Al silicates occur.-R.A.H.

    Original languageEnglish
    Pages (from-to)321-333
    Number of pages13
    JournalMineralogical Magazine
    Volume49
    Issue number3
    Publication statusPublished - Jan 1 1985

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    ASJC Scopus subject areas

    • Geochemistry and Petrology

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