Margarite-paragonite-muscovite assemblages from the low-grade metapelites of the Tono metamorphic aureole, Kitakami Mountains, Northeast Japan

Saved in:
Authors:Okuyama-Kusunose, Yasuko
Author Affiliations:Primary:
Geol. Surv. Japan, Ibaraki, Japan
Volume Title:Ganseki Kobutsu Kosho Gakkai-Shi Journal of the Japanese Association of Mineralogists, Petrologists and Economic Geologists
Source:Ganseki Kobutsu Kosho Gakkai-Shi = Journal of the Japanese Association of Mineralogists, Petrologists and Economic Geologists, 80(12), p.515-525. Publisher: Nippon Ganseki Kobutsu Kosho Gakkai, c/o: Tohoku Daigaku Rigakubu, Sendai, Japan. ISSN: 0021-4825
Publication Date:1985
Note:In English with Japanese summary. 31 refs.; illus. incl. 3 tables, 1 plate, geol. sketch map
Summary:Margarite occurs in the low-grade zone of the contact aureole of the Tono granitic mass, coexisting with muscovite, paragonite, chlorite and quartz, but without carbonates and feldspars. Chemical compositions of white micas, chlorite and chloritoid are given, as well as those of margarite-bearing and margarite-free metapelites. The margarite is produced by the reaction between pyrophyllite and zoisite in progressive metamorphism at T near the upper stability limit of the assemblage margarite + quartz. The solubility of the muscovite component in paragonite in the three white-mica assemblage (margarite, paragonite, and muscovite) is suppressed compared to that in the muscovite-paragonite assemblage, whereas the paragonite solubility in muscovite in the three white-mica assemblage is similar to that of the two-phase assemblage. The paragonite component in margarite in the three-phase (three white mica) assemblage of this area is 17.3-22.5 mol.%; this value is the smallest for margarite in the three-phase assemblages ever reported. The low paragonite solubility of margarite in this area is probably due to the low-P condition of the contact metamorphism. [K.O.]
Subjects:Aureoles; Contact metamorphism; Granites; Igneous rocks; Intrusions; Margarite; Metamorphic rocks; Metamorphism; Metapelite; Metasedimentary rocks; Mica group; Mineral assemblages; Muscovite; Paragonite; Petrology; Phase equilibria; Plutonic rocks; Sheet silicates; Silicates; Solubility; Asia; Far East; Honshu; Iwate Japan; Japan; Kitakami Mountains; Northeastern Japan; Tono metamorphic aureole
Abstract Numbers:87M/6944
Record ID:1986033999
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom
Tags: Add Tag
No Tags, Be the first to tag this record!
Be the first to leave a comment!
You must be logged in first