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タイトルヨミ
サングン ヘンセイガン チュウ ノ デイシツ ヘンガン ヨリ サンスル ローソン セキ
日本語以外のタイトル
Lawsonite from Quartzofeldspathic Schist in the Sangun Metamorphic Belt, Shikuma, Shimane Prefecture
ファイル
言語
英語
著者
渡辺 暉夫
小林 英夫
千貫 浩
内容記述(抄録等)
Lawsonite is a calcium-aluminosilicate characteristically occurs in the high pressure−low temperature type metamorphic terranes. It occurs ubiquitously in pelitic, psammitic, and mafic rocks with sodic amphibole in the typical high P/T type metamorphic terranes such as Franciscan and New Caledonia (MIYASHIRO, 1973 ; TURNER, 1980, etc.). However, in the Sangun metamorphic belt of which mineral assemblages represent lower pressure type of glaucophanitic metamorphism, lawsonite was thought to occur only in a part of mafic rocks and a part of psammitic rocks (SAKAKI & YAMAMOTO, 1967 ; HASHIMOTO & IGI, 1970 ; NISHIMURA & OKAMOTO, 1976).
The occurrence of lawsonite is very rare, so its stability range in the zonation of the Sangun metamorphism is not yet established. The rare occurrence is considered to be delicately controlled by bulk chemical compositions of small domains of centimeters or millimeters scale. According to the detail description by Nishimura & Okamoto (1976), lawsonite has close relation with chlorite-albite assemblage.
In quartzofeldspathic schists, Iawsonite was not recognized at all in the Sangun belt by any petrologists. The mineral assemblages in these schists, especially in the low grade area of the Sangun belt, were considered to be monotonous as compared with those in mafic rocks. However, the authors have recently found lawsonite in quartzofeldspathic schist of the Sangun belt from Shikuma, Shimane prefecture.
As quartzofeldspathic schists distribute most extensively in the Sangun belt although some different lithofacies are recognizable, the consideration on genesis of lawsonite in quartzofeldspathic schists is important to fully understanding of the Sangun metamorphism.
In this paper, the authors will give brief description of occurrence of lawsonite in Shikuma, Gotsu city, Shimane prefecture and a consideration on its genesrs.
掲載誌名
島根大学理学部紀要
17
開始ページ
81
終了ページ
86
ISSN
03879925
発行日
1983-12-25
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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