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タイトルヨミ
シマネケン ミトチョウ ホクトウブ ノ サングン ヘンセイ ガンチュウ ノ アルカリ カクセンセキ ノ サンジョウ ト キョウセイ カンケイ
日本語以外のタイトル
Occurrence and Paragenesis of Alkali Amphibole from the Sangun Metamorphic Rocks in the Northeastern Part of Mito-cho, Shimane Prefecture, Japan
ファイル
言語
英語
著者
渡辺 暉夫
小林 英夫
安達 浩
内容記述(抄録等)
Outline of geology in the studied area is given and original rocks of greenschists distributed in 8 horizons are estimated to be mainly volcanic sand/mudstones. A metamorphosed sheet showing bostonitic texture under the microscope is found in this area and its chemical compositron is similar to that of mugearite and its differentiation products.
The chemical compositions of greenschists are not necessarily basic. Mineral assemblages in greenschists are listed in this paper.
Two kinds of composite amphibole-grains are recognized in the geenschists. One of them is zoned amphibole, in which Al-poor crossite is usually rimmed by actionolite. The other kind of composite amphibole-grain is composed at least of three parts, i.e., magnesian hastmgsitic hornblende, actionolite, and winchite. Although this amphibole grain is optically homogeneous at a glance, back-scattered electron observation reveals chemical heterogeneity in micron scale. The result of line scanning analysis for some major elements shows that the chemical heterogeneity in the amphibole is more complicated, especially in MgO and total FeO contents. On the basis of stability fields of amphibole proposed by BANNO and OTSUKI (1982), P-T condition of the Sangun Metamorphism in this area is tentatively estimated.
This chemical heterogeneity in amphibole in micron scale may be a new mode as to chemical haterogeneity in amphibole.
掲載誌名
島根大学理学部紀要
16
開始ページ
143
終了ページ
157
ISSN
03879925
発行日
1982-12-25
NCID
AN00108106
出版者
島根大学理学部
出版者別表記
The Faculty of Science, Shimane University
資料タイプ
紀要論文
部局
総合理工学部
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