巻号一覧
38 巻 (1984)
- 6 号 p. 380-
- 5 号 p. 281-
- 4 号 p. 221-
- 3 号 p. 143-
- 2 号 p. 75-
- 1 号 p. 1-
38 巻, 4 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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地史からの検討秋山 雅彦原稿種別: 本文
1984 年 38 巻 4 号 p. 221-225
発行日: 1984/07/25
公開日: 2017/07/27
ジャーナル オープンアクセスExtremely low abundance of carbonate rocks in the Archean, constant δ13C difference between the carbonate and organic carbons throughout the geologic time, and many other geologic evidences seem to support the intermittent degassing through the geological history. This proposal is in contrast with the catastrophic early degassing (OZIMA, 1978) and also the continuous degassing (RUBEY, 1951). An argon isotope ratio of 295.5 can be consistently interpreted by the survival on the earth's surface of argon gas of 1.7×l017g which is attributed to the primordial solar nebula.抄録全体を表示PDF形式でダウンロード (678K) -
下総台地研究グループ原稿種別: 本文
1984 年 38 巻 4 号 p. 226-234
発行日: 1984/07/25
公開日: 2017/07/27
ジャーナル オープンアクセスThe marine Quarternary system is widely exposed in the Shimosa Upland in the Kanto District, Central Japan. The pleistocene deposits in this area are divided into the following stratigraphic units in ascending order: the Kamiiwahashi, the Kioroshi, the Ryugasaki Sand, the Joso Clay, and the Kanto Loam Formations. The Kioroshi Formation (Late Pleistoceneage) is mainly composed of sands locally including abundant mollascan shells and covers the Kamiiwahashi Formation unconformably. This paper presents on the relation between the shape of base of the Kioroshi Formation and its sedimentary facies. 1) The base of the Kioroshi Formation cuts deeply up to 10 meters the Kamiiwahashi Formation, forming a the valley-like topography. This boundary surface, precisely, shows step-like and is divided into four unconformable subsurface (I-IV) according to their relative heights. 2) The Kioroshi Formation is divided into two members. The lower member of consists mainly of mud or muddy sand, and fills up the concavity cut the Kamiiwahashi Formation. The upper member, on the contrary, consists mainly of medium sand, and is distributed in whole area studied. 3) Based on the sedimentary facies, distribution, and occurrence of fossil molluscs, it is concluded that the lower member of the Kioroshi Formation was deposited under strong embayment degree, while the upper was of more neritic. Further, it is supposed that the sea-level at that time had been stayed until the beginning of deposition of the upper member.抄録全体を表示PDF形式でダウンロード (1452K) -
井上 多津男原稿種別: 本文
1984 年 38 巻 4 号 p. 235-248b
発行日: 1984/07/25
公開日: 2017/07/27
ジャーナル オープンアクセスThe Miocene series consisting largely of pyroclastic and volcanic rocks of dacitic to andesitic composition has been subjected to green tuff alteration. In this area, chlorite-chlorite-saponite mixed layer in andesitic pyroclastic rocks and clinoptilolite・mordenite in dacitic pyroclastic rocks have been formed under same conditions. Then, zoning of alteration was examined for the dacitic pyroclastic rocks distributed extensively in the surveyed area. The altered dacitic pyroclastic rocks are divisible into three zones, such as, Zone I (montmorillonite zone), Zone II (chlorite-sericite zone), and Zone III (kaolin zone). Furthermore, Zone I can be subdivided into clinoptilolite-mordenite subzone, mordenite subzone, and analcime subzone on the basis of zeolite mineral content. Zone I and its underlying Zone II have been formed in the Hata Formation of the lower Miocene in the age, and the boundary between them is almost parallel to original depositional surface. At a horizone of this boundary analcime appears sporadically. During the middle Miocene Kuri Formation, Zone I, II, and III have been formed again. This zone II and III are oblique to the bedding planes. Chlorite being a characteristic mineral of Zone II and kaolin coexist within the middle part of Zone III, and petrographic relationships indicate that chlorite is partly replaced by kaolin. Therefore the formation of Zone, III followed that of Zone II.抄録全体を表示PDF形式でダウンロード (2582K) -
田辺団体研究グループ原稿種別: 本文
1984 年 38 巻 4 号 p. 249-263
発行日: 1984/07/25
公開日: 2017/07/27
ジャーナル オープンアクセスThe Tanabe Group develops in the southwestern part of the Kii Peninsula . It overlies the Otonashigawa Group(Eocene?) in the northern part and the Muro Group(Oligocene−Lowest Miocene)in the southern part with a remarkable clino−unconformity,and is overlain unconformably by the Tohshima Conglomerate Bed. The Tanabe Group is lithologically divided into two formatiolls,namely the Asso Formation and the Shirahama Formation in ascending order. The Asso Formation is subdivided into three members (A1, A2 and A3)and the Shirahama Formation into five members (S1,S2,S3,S4 and S5).The Asso Formation is composed mainly of mudstone and conglomerate. The Shirahalna Formation consists of sandstone,alternations of sandstone and mudstone,and conglolnerate.Total thickness of the group attains to more than 1,100m.The geological structure of the group is characterized by the foldlngs showing ENE−WSW trend and westward plunging,and also by E−W and N−S trending faults. The geologlc age of Member A3 of the Asso Formation is correlated to the upper part of Blow’s N8 by the yieldings of some foraminifers：Praeorbtdlina glomerosa,Pro.cf. transitoria and Globigerinoides sicanus.The Tanabe sedimentary basin is discussed and attempted to reconstruct,based on the lithology and the lateral change in thickness as well as on the preliminary study on the paleocurrents.抄録全体を表示PDF形式でダウンロード (3084K) -
田沢 純一, 相田 吉昭, 結城 智也, 大槻 憲四郎原稿種別: 本文
1984 年 38 巻 4 号 p. 264-267
発行日: 1984/07/25
公開日: 2017/07/27
ジャーナル オープンアクセスPDF形式でダウンロード (657K) -
山崎 円, 大上 和良, 永広 昌之, 大石 雅之原稿種別: 本文
1984 年 38 巻 4 号 p. 268-272a
発行日: 1984/07/25
公開日: 2017/07/27
ジャーナル オープンアクセスPDF形式でダウンロード (1015K)
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