Studies of holohyaline rocks from Hokkaido, Japan I.:Perlites from Okushiri Island
スポンサーリンク
概要
- 論文の詳細を見る
Perlites, naturally occurring phenomena of Okushiri Island, can be divided into the following three types by their petrographic features: A. massive type. B. pumiceous type. C. flow-textured type. They are very similar to each other in petrochemical character. Perlites from Okushiri contain large quantities of microlite, crystallite and small amounts of phenocrysts which consist of oligoclase, quartz and biotite. Based on X-ray spectrographical analysis and optical examination it can be deduced that the microlite essentially consists of oligoclase, albite and cristobalite with small amounts of biotite and quartz. A comparison study of Okushiri perlites to microlite indicates that perlite is less crystalline in structure than microlite. Okushiri perlites and those from other parts of Japan, although poor in CaO content, are rich in alkalies, especiallyin K2O and when plotted against the ternary eutectic point on the Q-Or-(Ab+An) triangular diagram devised by Bowen and Vogt. Also, the (Fe2O3+FeO)-(Na2O+K2O)-MgO triangular plot indicates that perlites concentrate near the apex (Na2O+K2O) listed in Kuno's hypersthenic rock series. Okushiri perlites are easily transformed into natural glass by heating and rapid cooling into a solid state. Thus producing a glass of high alkalies and silica similar to magma which has undergone the same physical transformations. As founded by differential thermal and thermogravimetric analyses, the H2O content was gradually dehydrated.
- 日本鉱物科学会の論文
日本鉱物科学会 | 論文
- シリケイトメルト中の水の拡散
- 岡山市北西部, 日近花崗閃緑岩体の岩石記載および全岩化学組成
- 高エネルギー陽子マイクロビームによる鉱物中の水素定量分析法の開発
- 日本海竹島海山(仮称)のかんらん岩捕獲岩の成因とその意義
- 高輝度 高指向 連続光・直線偏光の単結晶X線回折への恩恵