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, 2 号
選択された号の論文の7件中1～7を表示しています
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田沢 純一原稿種別: 本文
1988 年 42 巻 2 号 p. ii-
発行日: 1988/03/25
公開日: 2017/06/06
ジャーナル フリーPDF形式でダウンロード (610K) -
木村 純一, 林 義隆原稿種別: 本文
1988 年 42 巻 2 号 p. 43-60
発行日: 1988/03/25
公開日: 2017/06/06
ジャーナル フリーNeogene volcanic rocks and sedimentary rocks distributed over the Hijiriyama area, Nagano Prefecture, Central Japan are divided into four formations. They are the Omi, Ohoka, Shinkou and Haibara Formations in ascending order. Each of these formations have an unconformable relationship with underlying formations. The Omi Formation is mainly composed of clastic rocks, rhyolitic tuff layers and altered andesitic lava flows. The Ohoka Formation is mainly composed of dacitic to andesitic lava flows and/or pyroclastic rocks. The Shinkou Formation is mainly composed of andesitic to basaltic lava flows and/or pyroclastic rocks. The Haibara Formation is mainly composed of fluvial sediments. Results of chronology on the Neogene volcanic rocks and sedimentary rocks are as follows: Haibara Formation: Late Pliocene to Early Pleistocene Shinkou Formation: Middle Pliocene Ohoka Formation: Latest Miocene to Early Pliocene Omi Formation: Late Miocene These chronological data resulted in the recognition of two times of Pliocene volcanism in the Hijiriyama area; the first occurs in Latest Miocene to Early Pliocene, and the second in Middle Pliocene.抄録全体を表示PDF形式でダウンロード (2133K) -
風岡 修原稿種別: 本文
1988 年 42 巻 2 号 p. 61-83
発行日: 1988/03/25
公開日: 2017/06/06
ジャーナル フリーThe Plio-Pleistocene Uonuma Group, well exposed in the Higashikubiki Hills of Niigata Prefecture, Central Japan, attains more than 2,500 m in total thickness. The Uonuma Group, partially interfingering with the Hachioji Formation of the Chuetsu Group, is divided into four parts, namely, lowermost, lower, middle and upper parts, based on the volcanic ash layer. Clastic sediments of the Uonuma Group mainly consist of irregular or cyclic alternation of gravel, sand and silt. Seventeen sets of ash layers, eight lapilli zones, six tuff breccia beds and fifteen marine beds are intercalated in the Uonuma Group. They are very important as marker beds for the establishment of stratigraphy. The marine beds interbedded with the non-marine beds suggest that transgressive and regressive processes were controlled probably by the eustatic sea-level changes or tectonic movement on more wide area than the Uonuma Sedimentary Basin. The change of sedimentary environment of the Uonuma Group was revealed by investigation of gravel composition, distribution of gravel beds and paleo-current. At the age of the Lowermost Part, deltas in the south and fan-deltas in the east were formed and rapidly filled up shallow sea. At the age of the Lower Part, there were alluvial fans in the east and fluvial plain with small river in the Matsudai area. Marshes spreaded widely. At the age of the Middle Part, alluvial fans in the east spreaded. Along the Shibumigawa Syncline, there was a fluvial plain with large river, marshes and flood plains, as large as Shinano River in the present Niigata Plain. There may have been the source of the river in the Nagano area to the southwest. At the age of the Upper Part, alluvial fans in the east spreaded widely, and the Uonuma Hills may uplifted partially. There was a fluvial plain continuously along the Shibumigawa Syncline. According as the slope of river became steep by the uplift of source areas, the large-sized gravels were transported from the south and deposited along the Shibumigawa Syncline.抄録全体を表示PDF形式でダウンロード (2643K) -
1. サンゴ礁岩塊の移動と津波遡上高加藤 祐三, 日高 和己, 川野 良信, 新城 竜一原稿種別: 本文
1988 年 42 巻 2 号 p. 84-90
発行日: 1988/03/25
公開日: 2017/06/06
ジャーナル フリーOn the basis of a distribution of Recent reef blocks scattered on Tarama Island, the southern Ryukyu Islands, a behavior and a run-up height of Yaeyama Seismic Tsunami (1771) which swept over the Island from SW can be inferred. There are many reef blocks in Tarama Island and they fall into two kinds : Recent reef blocks and Pleistocene Ryukyu Limestone blocks. From the distribution of the latter the movement of the tsunami cannot be inferred. However, as all Recent reef blocks on the Island are considered to have been thrown on the land by the tsunami, it can be inferred how the tsunami took place. Based on the fact aragonites, components of coral fossils in Recent reef blocks, are not inverted to calcite, the Recent reef blocks can be distinguished from the Ryukyu Limestone blocks. As a result of an examination of the distribution of Recent reef blocks and the topography of the sea floor and Tarama Island, it has been inferred that there were five northheaded strong branches of the tsunami on the Island. Western two branches ran across the Island and pushed many blocks to the north shore of the Island. The central strong branch moved many blocks from the sea area to the land or within the inland towards northward. This was the very branch that threw some Recent coral blocks over to 17m above the sea level, the highest level of the places where the blocks were thrown over. On the basis of altitude and height of the block, the highest run-up height of the tsumani at the Island was inferred to be a little higher than 18m.抄録全体を表示PDF形式でダウンロード (1241K) -
渡辺 寧, 山口 昇一原稿種別: 本文
1988 年 42 巻 2 号 p. 91-99
発行日: 1988/03/25
公開日: 2017/06/06
ジャーナル フリーThe volcanic rocks in the Nayoro-Asahikawa region, northern Hokkaido, can be divided petrographically into three districts from west to east as follows: Nakagawa-Horokanai, Utanobori-Toma and Omu-Kamikawa districts. In the Nakagawa-Horokanai district, hornblende andesite associated with pyroxene andesite is abundant, while pyroxene andesite is uniquely exposed in the Utanobori-Toma district. In the Omu-Kamikawa distict, pyroxene andesite occurs associated with rhyolite, dacite and basalt. K-Ar ages of these volcanic rocks indicate that the volcanism in the Omu-Kamikawa and the Utanobori-Toma districts took place 9.8-12.1 Ma and 9.3-13.8 Ma, respectively. Thus, it is considered that the volcanism in these three districts occurred simultaneously during the period from late Middle Miocene to early Late Miocene. Moreover, the ages of the volcanic rocks tend to become younger toward the south in the Nayoro-Asahikawa region. The sedimentary environment inferred from the sediments intercalated with these volcanic rocks shows that the volcanism was mostly terrestrial. From the viewpoints of the age, activity trend and distribution of volcanic rocks, the Middle Miocene to Late Miocene volcanism in the Nayoro-Asahikawa region is clearly distinguished from the Paleogene to Early Miocene plutonism in central Hokkaido and also from the volcanism having occurred along the Kulile Arc since Late Miocene.抄録全体を表示PDF形式でダウンロード (1061K) -
西坂 昌美, 吉村 尚久原稿種別: 本文
1988 年 42 巻 2 号 p. 100-103
発行日: 1988/03/25
公開日: 2017/06/06
ジャーナル フリーPDF形式でダウンロード (537K) -
松岡 篤原稿種別: 本文
1988 年 42 巻 2 号 p. 104-106
発行日: 1988/03/25
公開日: 2017/06/06
ジャーナル フリーPDF形式でダウンロード (594K)
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