THE SEQUENCE OF P-T CURVES AROUND A QUATERNARY INVARIANT POINT IN THE SYSTEM NaAlSiO4-KAlSiO4-SiO2-H2O

NaAlSiO4-KAlSiO4-SiO2-H2O 4성분계(成分系)의 불변점부근(不變點附近)의 P-T 곡선(曲線)의 변이(變移)

  • Kim, Ki-Tae (Institute of Geophysics and Planetary Physics, University of California)
  • Published : 1972.06.30

Abstract

The system NaAlSiO_4-KAlSiO_4-SiO_2-H_2O, Bowen's "Petrogeny's Residua System" of course is extremely important in understanding the phase relationships of igneous and metamorphic rock in the continental crust. The phase relationships in this system, however, have not been completely established in the P-T range above the Mohorovicic discontinuity. They need to be established. In this study, the most probable sequence of P-T curves around a quaternary invariant point(~5Kb/${\sim}635^{\circ}C$) in the system using Schreinemakers' rule, is deduced, essentially on the basis of Morse's(1969a and b) experimental data. Possible modifications of the sequence of the P-T curves considering likely changes of the invariant chemogram are also considered. It is concluded that the sequence of P-T curves around the invariant point (~5Kb/${\sim}635^{\circ}C$) is (L), (Anl), (Or), (V), (Ne) and (Ab) on the P-T projection, where the P-T curve (L) is extended towards lower P-T regions, and the (Anl) curve is extended towards a region of higher temperature and lower pressure from the invariant point respectively.

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