巻号一覧
73 巻, 5 号
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金原 啓司, 大久保 太治1978 年 73 巻 5 号 p. 125-136
発行日: 1978/05/05
公開日: 2008/08/07
ジャーナル フリーIn 1974, an exploration bore-hole, No. SA-1, had been drilled up to 500 meters in depth in the Satsunan geothermal area, southern Kagoshima. Temperature at the bottom is over 240°C and the chemical composition of thermal water gives a type of Na-Ca-Cl called as “coastal thermal water” which is derived from sea water. Rocks in the bore-hole suffer extremely hydrothermal alteration characterized by the presence of chloritic clay minerals. By interaction between the coastal thermal water (sea water) and rocks, chlorite has been formed from volcanic glass and mafic minerals through the stage of Al-montmorillonite, Mg, Fe-saponite and interstratified mineral of chlorite and montmorillonite (saponite). An interstratified mineral of sericite and montmorillonite occurs locally above the part of the lost-circulation of drilling-mud. Gypsum is found through the all core. Mordenite and clinoptilolite occur in the upper part and wairkite occurs in the lower part. Zeolite such as laumontite, however, cannot be detected in the middle part. It is considered that all alteration minerals in the No. SA-1 have been formed by interaction between coastal thermal water and rocks under the recent physicochemical condition.抄録全体を表示PDF形式でダウンロード (1947K) -
紫田 賢, 野沢 保1978 年 73 巻 5 号 p. 137-141
発行日: 1978/05/05
公開日: 2008/08/07
ジャーナル フリーK-Ar ages have been determined on hornblendes from seven metamorphic rocks and two Funatsu Granitic Rocks from the Hida Metamorphic Belt. The ages of metamorphic rocks range from 174 to 223 m.y., and grouped into two: about 220 m. y. and 175-195m.y. The former ages represent the time of the main metamorphism in the Hida Metamorphic Belt, whereas the latter may have resulted from rejuvenation by the intrusion of the Funatsu Granitic Rocks or from slow cooling.
An age or 180m.y. is obtained on hornblende from the Shimonomoto type of the Funatsu Granitic Rocks, and it confirms the time of intrusion for the Funatsu Granitic Rocks. Hornblende from augen gneiss, gives an age of 213m.y., which is similar to that of hornblendes from the Hida Metamorphic Rocks, thus suggesting that the augen gneiss is genetically different from the typical Funatsu Granitic Rocks. It is interpreted that hornblendes dated here contain no excess argon.抄録全体を表示PDF形式でダウンロード (240K) -
HISASHI TAKESHITA1978 年 73 巻 5 号 p. 142-151
発行日: 1978/05/05
公開日: 2008/08/07
ジャーナル フリーAs evidences on pyroclastic flows show that their welded parts are largely composed of glass, the writer has made a thermal experiment on powdered samples of natural glasses from several localities to find the welding temperature and associated physical conditions. As the result of this experiment the welding of glasses of rhyolitic to felsic andesite composi-tion was recognized at about 950°C at the minimum under atmospheric pressure, whereas under hydrostatic pressure of 30-50 bar, obsidian or perlite glass was welded at 550°C under hydrothermal condition, or at 600°C under dry condition. It is interesting that a scoria from the somma effusives of the Aso Caldera was not welded at 750°C under hydrostatic pressure of 20-30 bar and barely welded at the same temperature at 50 bar, whereas an obsidian-like crust around the socria, which is rich in potash compared with that of the scoria, was welded at 550°C under hydrothermal condition as well as dry condition at 20-40 bar. Its ferrous oxide content was decreased from 950 to 1050°C, and at a higher temperature than 1050°C the oxide was abruptly increased in content, accompanied with bubbling.抄録全体を表示PDF形式でダウンロード (3013K) -
四国東部高越地域からパラゴナイトを伴う石英片岩の発見平村 まき子1978 年 73 巻 5 号 p. 152-154
発行日: 1978/05/05
公開日: 2008/08/07
ジャーナル フリー徳島県高越地域の石英片岩にはパラゴナイトを含むものが産する。産地は徳島県山川町の榎谷部落の西方を流れ,大内では川田川の上流奥野井谷に合流する沢の上流で,標高500mの地点で,標本は転石である。その岩石は石英+ルチル+クロス閃石+ざくろ石+白雲母+パラゴナイト+緑れん石の鉱物組合せを持つ。また,この岩石の白雲母はセラドナイト成分を約40%含む。抄録全体を表示PDF形式でダウンロード (143K)
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