巻号一覧
42 巻 (1988)
- 6 号 p. 317-
- 5 号 p. 241-
- 4 号 p. 165-
- 3 号 p. 109-
- 2 号 p. 43-
- 1 号 p. 1-
42 巻, 3 号
選択された号の論文の9件中1～9を表示しています
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小高 民夫原稿種別: 本文
1988 年 42 巻 3 号 p. ii-
発行日: 1988/05/25
公開日: 2017/06/06
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進化した紡錘虫の1種長谷川 美行原稿種別: 本文
1988 年 42 巻 3 号 p. iii-v
発行日: 1988/05/25
公開日: 2017/06/06
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関東平野北西縁における前期更新世堆積盆地の形成について小野上団体研究グループ原稿種別: 本文
1988 年 42 巻 3 号 p. 109-123
発行日: 1988/05/25
公開日: 2017/06/06
ジャーナル オープンアクセスThe strata distributed in the lower Agatsuma River, northwestern part of the Gunma Prefecture, Central Japan, consist of the Miocene Yago Formation and the Pleistocene Onogami Formation. The marine middle Miocene Yago Formation is composed mainly of coarse-grained tuffs, accompanied partly with pumice tuffs and mudstones. The aqueous sediments of the Onogami Formation deposited in early Pleistocene covers the Yago Formation with anguler unconformity and is divided into four members in ascending order: the Shimoichishiro Breccia Member composed mainly of debris flow deposits, the Sakaizawa Pumice Tuff and Mudstone Member, the Iwaido Tuff Breccia Member composed of andesitic hyaloclastites and its fragmental deposits, and the Horinouchi Sandstone and Mudstone Member characterized by slump beds. After the deposition of the Onogami Formation, several andesitic and dacitic dykes intruded with direction of WNW-ESE; the lower Omogami Formation had fold axes of WNW-ESE and NNE-SSW. The Onogami basin in which the Onogami Formation was deposited is a structual collapsed one recognized as a type of the Island Arc disturbance advocated by Fujita in 1982. It was proved that the Onogami basin had been restricted by several tectonic lines estimated below the surface of the northwestern margin of the Kanto Plain.抄録全体を表示PDF形式でダウンロード (1783K) -
足柄地域の新第三系・第四系の研究(4)足柄団体研究グループ原稿種別: 本文
1988 年 42 巻 3 号 p. 124-136
発行日: 1988/05/25
公開日: 2017/06/06
ジャーナル オープンアクセスThe results of the present study are summarized as follows: 1. The Ashigara sedimentary basin is inferred to have been formed by the collapse of the south side of an E-W fault which occurred along the eastern half of the Kannawa fault just before the sedimentation of the Doyama Formation, the lowermost formation of the Ashigara Group. This E-W fault would appear concurrently with a fault which intersects the north and south sides of the Shirakurazawa Formation in the E-W direction. 2. In the Ashigara sedimetary basin, the center of sedimentation shifted gradually west-ward as a result of the asymmetric subsidence along the intra-basement fault originated at the generative stage of the basin. 3. The flexure zone in the Ashigara sedimentary basin was formed when the subsidence on the southeast side of the basin turned to upheaval. 4. Throughout the whole stages of formation, development and deformation of the Ashigara sedimentary basin, the reactivation of the pre-existent fractures in the basement was the most essential factor for the geological phenomena in the respective stages. Moreover, the fractures in the basement are considered to be controlled by the geological structures observed today in the Tanzawa Group. 5. The Kannawa fault has resulted from the reactivation of the two kinds of fractures; one was supposedly formed during the sedimentation of the lowermost part of the Ashigara Group observed on the earth's surface, and the other was formed during the sedimentation of the Shiozawa Formation, the upper part of the Ashigara Group. After the sedimentation of the Ashigara Group, these fractures began to be reactivated again when the Tanzawa side was markedly upheaved, and resulted in the faults that are partly low-angled thrust faults and mostly high-angled reverse faults. As the more intense upheaval of the Tanzawa side continued, the Kannawa fault came to be intersected by a conjugate set of strike-slip faults. 6. The Tanzawa-Ashigara area can be regarded as one geotectonic province. Accordingly, a view that the Ashigara and the Tanzawa areas belonging to different tectonic provinces and collided to be united is not acceptable.抄録全体を表示PDF形式でダウンロード (1547K) -
雁沢 好博, 本多 照幸, 野崎 徹也原稿種別: 本文
1988 年 42 巻 3 号 p. 137-146
発行日: 1988/05/25
公開日: 2017/06/06
ジャーナル オープンアクセスThe absolute measurements of thermal neuron fluence for fission track dating have been developed after the proceeding results of Honda et al. (1987). The 2,200 m/sec activation cross section of 197Au (98.8 barn) is corrected to 87.4 barn (σa) by the three factors of the neutron temperature, Maxwellian distribution of thermal neutrons and non Ijv correction factor for the above absolute measurement. The calibrated factor (Bth) of standard glasses (SRM613, SRM962a, CN-1 and CN-2) and zeta-a (ζa) values for fission track dating are determined on the basis of these experimental results. The values of Bth, (7.47±0.29)×109 for SRM613, (7.43±0.34)×109 for SRM962a, (2.50±0.06)×109 for CN-1 and (2.74±0.06)×10109 for CN-2 closely agree with those reported previously by Honda et al. (1987). Further, the Co. values of 392.3±16.5 for SRM962a and SRM613,131.4±3.1 for CN-1 and 144.1±3.3 for CN-2 calculated from Bth, effective thermal neutron fission cross-section σf> (497.4 barn), isotopic abundance ratio 235U/239U, I (7.2527×10-3) and spontaneous fission decay constant of 238U, λf (6.85×10-17a-1) show close agreement with ζb values (392.5±10.0, 131.6±3.3, 140.1±3.5) derived from the absolute age of Fish Canyon Tuff (27.9±0.7Ma) respectively. The fission track dating of zircons separated from Oligocene-Miocene tuff distributed in Eastern Hokkaido have been carried out by the external detector method using ζa. The_obtained ages are 28.6±0.7 Ma (1-2) and 23.3±0.7 Ma (3-2). These results agree well with the geologic age supported from Ashoro Fossil Fauna, K-Ar ages of volcanic rocks and stratigraphy in this area.抄録全体を表示PDF形式でダウンロード (951K) -
鈴木 清一, 都郷 義寛原稿種別: 本文
1988 年 42 巻 3 号 p. 147-154c
発行日: 1988/05/25
公開日: 2017/06/06
ジャーナル オープンアクセスThe internal structure and mineralogy of the calcined opercula of eight species of neritid gastropods have been studied. The neritid opercula studied consist of an organic layer and two or three calcined ones. They are classified into two types, "separate" and "non-separate", from a developing manner of the organic and calcified layers. In the separate type, the calcification is performed on both the inner and outer sides of the organic layer so that the calcified opercula appear to be separated into two parts by the organic layer. In the non-separate type, the inner and outer calcified layers directly contact with each other, and a reduced organic layer attaches only to the periphery of the outer calcified layer along the outer-lip-side margin. The latter type may be derived from the former in the course of the evolution of the gastropod operculum. Every calcified layer is aragonitic with a small amount of organic matrices. The micro-structure is identified with the irregular prismatic structure. This microstructure tends to change gradually into a type of the complex crossed-lamellar structure, which is characterized by the irregular arrangement of the crystal aggregations within which acicular crystals are well ordered. This orderliness of crystal arrangement is probably due not to a geometric selection but to the other mechanism such as a split growth of crystal.抄録全体を表示PDF形式でダウンロード (4344K) -
八幡 正弘原稿種別: 本文
1988 年 42 巻 3 号 p. 155-158
発行日: 1988/05/25
公開日: 2017/06/06
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山岸 猪久馬原稿種別: 本文
1988 年 42 巻 3 号 p. 159-163
発行日: 1988/05/25
公開日: 2017/06/06
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原稿種別: 文献目録等
1988 年 42 巻 3 号 p. Misc1-
発行日: 1988/05/25
公開日: 2017/06/06
ジャーナル オープンアクセスPDF形式でダウンロード (37K)
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