地球科学
Online ISSN : 2189-7212
Print ISSN : 0366-6611
38 巻, 2 号
選択された号の論文の9件中1~9を表示しています
  • 野塚岳研究グループ
    原稿種別: 本文
    1984 年 38 巻 2 号 p. ii-iib
    発行日: 1984/03/25
    公開日: 2017/07/27
    ジャーナル オープンアクセス
  • 十和田火山(カルデラ)発達史に関連して
    斎藤 仁子, 大池 昭二
    原稿種別: 本文
    1984 年 38 巻 2 号 p. 75-83
    発行日: 1984/03/25
    公開日: 2017/07/27
    ジャーナル オープンアクセス
    The study of the late Dr. H. Kuno has been accepted as an established theory of the geological history of Towada Volcano (Caldera). His study was based upon only the geological data of the volcanic body of around the Lake Towada. The authors believed, however, that a correlative research of the tephra-stratigraphy of the foot-hills with the geology of the volcanic body would clarify a true geological history of Towada Volcano (Caldera). First of all this monograph is to clarify the geological and petrological character of the younger volcano which has not been made clear till now, and then to pursue the above-mentioned theme including the previous results. As an outcome of this study, a tentative conclusion was formed on the geological history of Towada Volcano (Caldera), which is shown Fig. 6. The main points are summarized as follows; [table]
  • 冨賀 肇, 石上 知良
    原稿種別: 本文
    1984 年 38 巻 2 号 p. 84-88a
    発行日: 1984/03/25
    公開日: 2017/07/27
    ジャーナル オープンアクセス
    In this article, the authors dealt with some proboscidean fossils occurred from the lower part of the Osaka Group (Early Pleistocene) at eastern part of the Habikino Hills in Tondabayashi City, Osaka Prefecture. Those fossils are composed of one broken molar, four complete and incomplete incisors (tusks of elephants) and other bone fragments. Those materials were found together in a restricted small spot in the area, and were confirmed to be yielded from the same bed, pebbly silt, which is probably about 30 m below the First Marine Clay bed (Ma 1) of the Osaka Group. The fossil molar was identified as a molar of Stegodon cf. akashiensis (TAKAI) from its characteristic features. On the other hand, it is not sure whether all of the present incisors belong exclusively to S. cf. akashiensis or not, but it may be possible to assume from consideration to form of incisors that there were another species. Therefore, it is necessory to examine the coexistence of S. cf. akashiensis with Mammuthus paramammonteus shigensis (MATSUMOTO et OSAKI) in this stratigraphic level. Among them, the latter species is known as a zone species designated for the stratigraphic level of the present fossil bed in the Osaka Group.
  • 安井 敏夫
    原稿種別: 本文
    1984 年 38 巻 2 号 p. 89-101
    発行日: 1984/03/25
    公開日: 2017/07/27
    ジャーナル オープンアクセス
    A mass of granite, which is covered unconformably by the Silurian-Devonian Yokokurayama Formation, is discovered in the Yokokurayama Lenticular Body of the Kurosegawa Tectonic Zone of Mt. Yokokura, Kochi Prefecture, and is named the Yokokurayama Granite. It is composed generally of medium-grained, hornblende-biotite granodiorite with some coarse-grained, pegmatitic varieties. It is characterized by 1) reddish potassium feldspar, 2) low grade of or almost devoid of mylonitization, and 3) zoned plagioclase. It is distinguished clearly from granites of the Mitaki Igneous Rocks. Many of the pebbles, grains and fragments of granite found in the Silurian sequence are identified with the granites of the Yokokurayama Granite.
  • 大分県南部蒲江湾周辺海域から採取した試料を使用して
    亀山 徳彦
    原稿種別: 本文
    1984 年 38 巻 2 号 p. 102-112
    発行日: 1984/03/25
    公開日: 2017/07/27
    ジャーナル オープンアクセス
    In this paper the relationships between the total benthic foraminiferal assemblages and the sediment characters, especially those of the fine grained part of sediment, were studied by using 17 dradge samples taken from the surrounding sea area of Kamae Bay, southern part of Oita Prefecture. As for the clustering, both MORISITA'S Similarity Index (1957) and SPEARMAN'S sum of variable formula (1963) were applied to benthic foraminiferal assemblages which 17 dradge samples contained. Consequently four groups were formed. Furthermore, 17 dradge samples were divided into five groups by the topographical features of sampling points. Such two kinds of groups resulted from the fact that the bottom sediment was formed under the influences of water movements, such as bottom current and wave turbulance, judging from the characters of fine grained part of sediment. Clay content, mud content and mean grain size of sediment probably represented the water movements mentioned above and clay content was the the most significant parameter tested.
  • Paolo A. PIRAZZOLI, 河名 俊男, Lucien F. MONTAGGIONI
    原稿種別: 本文
    1984 年 38 巻 2 号 p. 113-118a
    発行日: 1984/03/25
    公開日: 2017/07/27
    ジャーナル オープンアクセス
    沖縄県多良間島における後期完新性海面変動について論じた.離水ノッチ,ベンチ,ビーチロック,ノッチに付着するフジツボ化石および礁原上の原地性サンゴ化石等により,完新世における平均海面上約1.5mの相対的高海水準が想定される.ビーチロックおよび原地性サンゴ化石の年代測定,ノッチの形態および後退速度等より,最大数千年間にわたる相対的高海水準期が推定され,それ以後,徐々に海面が低下し現在に至ったものと考えられる.以上の海面変化は,多良間島に隣接する東方の宮古島および西方の石垣島における後期完新世の海面変動と異なっており,それらの相違は各地域毎の地殻変動の差異に帰因すると推察される.
  • 宮坂 省吾, 紺谷 吉弘, 君波 和雄, 木村 学, 保柳 康一, 高橋 功二, 山口 昇一, 松井 愈
    原稿種別: 本文
    1984 年 38 巻 2 号 p. 119-131
    発行日: 1984/03/25
    公開日: 2017/07/27
    ジャーナル オープンアクセス
    Some geological problems on the upheaval of the northern part of the Hidaka Belt, cased on the studies of the Miocene strata, Kitami-Takinoue region, are described. The Miocene strata can be divided into the following two units in ascending order; i. e., the Kamishiyubetsu Formation (early middle Miocene) and the Oshiraneppu-gawa Formation (middle Miocene). The coarse clastic materials in the lower part of the Kamishiyubetsu Formation have been derived from the Hidaka Supergroup, during early middle Miocene. After the deposition of the muddy facies in the upper part of the Kamishiyubetsu Formation, coarse clastic materials among the Oshirneppu-gawa Formation, i. e., sandstone, slate, phyllite, hornfels, granite, and other rocks, are supplied from N-S trending Uenshiri Horst Zone (NAKAMURA et al. 1980). The Uenshiri Horst Zone, at the Central part of the Hidaka Belt, became the mountain range during the early middle Miocene. This zone provides a large amount of coarse clastic materials to the sorrounding strongly subsiding the Ishikari-Teshio Belt and Okoppe-Shikaribetsu Belt area.
  • 田沢 純一
    原稿種別: 本文
    1984 年 38 巻 2 号 p. 132-134a
    発行日: 1984/03/25
    公開日: 2017/07/27
    ジャーナル オープンアクセス
  • 出脇 敏明
    原稿種別: 本文
    1984 年 38 巻 2 号 p. 135-138a
    発行日: 1984/03/25
    公開日: 2017/07/27
    ジャーナル オープンアクセス
feedback
Top