群馬県茶臼山溶結凝灰岩の地質構造と磁化

概要

論文の詳細を見る
The Chausu-yama Welded Tuff Bed is intercalated in the middle part of the Upper Miocene Akima Formation in the western part of Gunma Prefecture, Central Japan. It extends from Matsuida Town in the west to the northern part of Annaka City in the east for about 15 km. At the Yudono-yama area, it is folded to form an oblong dome with a WNW-ESE trending axis. Eighty to ninety percents of magnetic minerals in this bed are magnetite and the rest are maghemite altered from the former. Directions of magnetization of the rocks from many sampling sites well agree with each other except those from the folded part of the Yudonoyama area. When the attitude of the folded part is reconstructed to conform with other parts of the same bed, the orientation of the rock magnetism of that part becomes conformable with the general attitude of the other parts. It shows that the original directions of magnetism of the Chausu-yama Bed are maintained since the time of its deposition.
日本地質学会の論文
1979-03-30