巻号一覧
41 巻 (1987)
- 6 号 p. 297-
- 5 号 p. 253-
- 4 号 p. 205-
- 3 号 p. 151-
- 2 号 p. 81-
- 1 号 p. 1-
41 巻, 5 号
選択された号の論文の6件中1～6を表示しています
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田沢 純一原稿種別: 本文
1987 年 41 巻 5 号 p. ii-
発行日: 1987/09/25
公開日: 2017/06/06
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田沢 純一原稿種別: 本文
1987 年 41 巻 5 号 p. iii-
発行日: 1987/09/25
公開日: 2017/06/06
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その1. 岩石記載と貫入関係朝日団体研究グループ原稿種別: 本文
1987 年 41 巻 5 号 p. 253-280b
発行日: 1987/09/25
公開日: 2017/06/06
ジャーナル フリーThe Asahi Mountains, being located near the southwestern end of Northeast Japan, are important to understand the geological structure of Japan, because it has been commonly said that the Tanakura Tectonic zone is the boundary between the Southwest Japan and the Northeast Japan as regards pre-Neogene system. This paper will show an outline of the geology and petrography in the southwestern part of the Asahi Mountains. Low grade metamorphic rocks and various kinds of plutonic rocks are distributed widely in the southwestern part of the Asahi Mountains. The low grade metamorphites are named the Takenosawa formation which might be derived principally from Paleozoic and Mesozoic strata. They are composed mainly of pelitic, psammitic and siliceous phyllites and their alternating rocks. Judging from their mineral assemblages, this formation has been subjected to greenschist facies metamorphism before the Cretaceous plutonism. The plutonic rocks are divided largely into two major groups, namely the older and the younger stages, based mainly on the relationships with the Suesawagawa rhyolitic welded tuff and the related volcano-hypabyssal rocks. These welded tuff and volcano-hypabyssal rocks and some of the older-stage plutonic rocks are thermally metamorphosed by the younger-stage plutonic rocks. The older-stage plutonic rocks, furthermore, can be divided into five concordant masses: Nishiasahi basic to intermediate complex, Ohasahi granodiorite, Ohtama granodiorite, Nakadake granodiorite and Sagami adamellite. The younger-stage ones, however, can be divided into seven concordant or partly discordant masses (Bakeana granodiorite complex, Heishiro adamellite, Miomote adamellite, Hiraiwa adamellite, Ito adamellite, Fine-grained diorite, and Biotite granitic rocks), and one perfectly discordant mass (Kakunara adamellite). The Takenosawa formation and the plutonic masses except for the Kakunara adamellite mass are, more or less, deformed by the remarkable mylonitization. The Kakunara adamellite mass, however, is chiefly affected by the cataclastic deformation, and the mylonitization occurs in some places.抄録全体を表示PDF形式でダウンロード (5393K) -
本多 照幸, 雁沢 好博, 野崎 徹也原稿種別: 本文
1987 年 41 巻 5 号 p. 281-289
発行日: 1987/09/25
公開日: 2017/06/06
ジャーナル フリーThe calibration factor (Bth) for uranium dosimeter glasses SRM 613 and SRM 962a and zeta value (ζa) for fission track dating have been discussed in this paper. The evaluation of the above factors has been carried out on the basis of the absolute measurements of thermal neutron fluence using Au foil monitors and measurements of induced fission track density. The dosimeter glasses and Au-monitors sets are irradiated for 5-120 minutes at the irradiation pit of TRIGA II type reactor facility of Musashi Institute of Technology (MITR). The experimental and theoretical results are as follows: 1) The 2200m/sec activation cross section of 197Au (98.8 barn) is corrected to 87.1 barn by the following three factors: i) the neutron temperature, ii) Maxwellian distribution of thermal neutrons and iii) non 1/v correction factor for the determination of true thermal neutron flux (φth). 2) The induced fission track density (ρd) of dosimeter glass is corrected to the true fission track density (ρd・th) which was produced by the thermal neutrons. The mean ratio of ρd-ρth is 1.045. 3) The mean value of (7.36±0.18)×10^9 is obtained for Bth (Φth/ρd・th). The 2200 m/s fission cross section of 235U (582.2 barn) is corrected to 496.6 barn (σf) by the above i)-iii) factors. Consequently, the mean value of ζ;a・th derived from Bth and σf is 387.8±9.4.抄録全体を表示PDF形式でダウンロード (823K) -
中川 登美雄原稿種別: 本文
1987 年 41 巻 5 号 p. 290-292
発行日: 1987/09/25
公開日: 2017/06/06
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日本の第四紀層の14C年代(167)中馬 教允, 千葉 茂樹原稿種別: 本文
1987 年 41 巻 5 号 p. 293-294
発行日: 1987/09/25
公開日: 2017/06/06
ジャーナル フリーPDF形式でダウンロード (238K)
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