巻号一覧
38 巻, 1 号
選択された号の論文の8件中1～8を表示しています
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大阪層群の古地磁気層序とフィッション・トラック年代市原 実, 吉川 周作, 川辺 孝幸, 三田村 宗樹原稿種別: 本文
1984 年 38 巻 1 号 p. 1-16
発行日: 1984/01/25
公開日: 2017/07/26
ジャーナル オープンアクセスOn the basis of geological, magnetostratigraphical and fission track age data, IIDA recently expressed his opinion that an unconformity, a time-gap of which ranges from 2.0 to 1.1 m.y. ago, exists in the Osaka Group along the River Tsuda. This paper represents the results of our investigation on the above-mentioned "Shiba Unconformity" in the drainage of the River Tsuda. The results are as follows, 1) Field evidence shows that no unconformity is observable in the Osaka Group. 2) Magnetostratigraphical study shows that Olduvai normal polarity zone exists in the Osaka Group. 3) Fission track ages of tuff layers of the Osaka Group are consistent with magnetostratigraphical subdivisions of it. The authors also state that Olduvai normal polarity zone is traceable in the Osaka Group of Keihanna Hills and in the Kobiwako Group of Konan Hills, south of Lake Biwa. From these facts it is revealed that so-called "Shiba Unconformity" does not exist in the Osaka Group.抄録全体を表示PDF形式でダウンロード (1547K) -
硬砂団体研究グループ原稿種別: 本文
1984 年 38 巻 1 号 p. 17-30
発行日: 1984/01/25
公開日: 2017/07/26
ジャーナル オープンアクセスKatazuna Bed found in a scattered pattern around the Omiya Upland is very indurated as compared with other Quaternary sand deposits. Its stratigraphy and sedimentological properties are examinated and discribed. The results are summerized as followings. 1) Katazuna Bed distributes in slightly high areas in comparison with the surroundness, and occurs in a thin ribbon or pod form with less than 2 m in thickness, 0.7 to 2km in width, and 2 to 5 km in length, and elongated in NNW to SSE. 2) Katazuna Bed covers the tuffaceous sand "Nukazuna Bed" conformably which is deposited under the fresh water conditions and is also covered conformably by upper Shimosueyoshi Loam formation composed of air fall deposits. Katazuna Bed is deposited about the fall stage of "Kuriyokan Pumice" (: KuP.). 3) Katazuna Bed is composed of well sorted sand grains and has white tubular materials composed of alophen clay with 2 or 3 mm in diameter, and may have been indurated by imogolite as cement materials. Based on above-mentioned results, the sedimentary environment of Katazuna Bed is in-ferred as followings. 4) Katazuna Bed is formed as the result of the regression of Paleo-Tokyo Bay and the bed is important as an environmental indicator of the time. We think that in the central part of the Kanto Plain the prevailing winds transported sand grains composing Nukazuna Bed, and formed the Katazuna Bed as small river dunes or thin sand layers.抄録全体を表示PDF形式でダウンロード (1309K) -
田倉山団体研究グループ原稿種別: 本文
1984 年 38 巻 1 号 p. 31-43
発行日: 1984/01/25
公開日: 2017/07/26
ジャーナル オープンアクセスThe Takurayama Volcano is located at the border of the Kyoto and Hyogo Prefectures in the northern part of the Kinki District. The volcano is composed of basaltic lava plateau named Yakunogahara, and scoria cone, Mt. Takurayma, with crater-like depression. It is the most eastern volcano among the alkaline basaltic volcanoes of the San-in province. The Quaternary deposits around the Takurayama Volcano are divided into four formations on the basis of their relationships with the Takurayama volcanism, those are pre-volcanic Mizaka Formation, syn-volcanic Yakunogahara Formation, and post-volcanic Kamiyakuno Formation and terrace deposits. The Mizaka Formation is composed of silty clay and sand with plant remains deposited in a rather stable lake existed prior to the commencement of the volcanism. This formation was deposited in a certain time of middle Pleistocene (between Ma4 and Ma7 of the Osaka Group). The Yakunogahara Formation was deposited in ponds dammed up by the lava flow. This formation is late Middle or early Late Pleistocene in age (later than the deposition of Ma8 and earlier than the formation of Middle Terrace). The Kamiyakuno Formation is the deposit of the small depression on the lava plateau in the glacial age of Wurm. The terraces are divided into the upper and lower ones, which are correlated to the Middle and Low Terraces, respectively. The lower terrace was formed in the glacial age of Wurm. Basaltic gravels derived from the volcano are contained in both the lower and upper terrace deposits. Volcanism of the Takurayama Volcano took place in late Middle or early Late Pleistocene, because it is contemporaneous with the deposition of the Yakunogahara Formation.抄録全体を表示PDF形式でダウンロード (1894K) -
石賀 裕明, 井本 伸広, 吉田 光広, 田辺 利幸原稿種別: 本文
1984 年 38 巻 1 号 p. 44-52b
発行日: 1984/01/25
公開日: 2017/07/26
ジャーナル オープンアクセス丹波帯南部,周山大森復向斜に分布する前期ペルム紀層状チャートよりPseudoalbaillella属放散虫を得た.この放散虫のうち4種(内,1種は新種)を記載するとともに露頭内での放散虫およびコノドントの居住学的分布を検討した.露頭は2本の断層により3つのブロックに分かれているが,3つの化石群集が識別され,最下位の群集はペルム紀ウルフキャンプ世最古期を示すと考えられる.抄録全体を表示PDF形式でダウンロード (1553K) -
剣山研究グループ原稿種別: 本文
1984 年 38 巻 1 号 p. 53-63
発行日: 1984/01/25
公開日: 2017/07/26
ジャーナル オープンアクセスThe Oboke area has been the type locality of the Sambagawa metamorphic rocks in Shikoku. We reexamined the stratigraphy and the geologic structure in this area, and the previous stratigraphy had been considerably revised as follows. The Sambagawa schists in this area are divided lithologically into three formations, i. e., the Kawaguchi, Koboke, and Minawa Formations. The Kawaguchi Formation is composed mainly of pelitic schist with subordinate amounts of basic, siliceous, calcareous and psammitic schists, kieslager, and metagabbros. The Koboke Formation is composed mainly of psammitic schist with small amounts of pelitic, conglomeratic and siliceous schists. The Minawa Formation consists mostly of pelitic schist with subordinate amounts of basic, siliceous and psammitic schists, and kieslager. The Kawaguchi Formation is interfingering with the lower part of the Koboke Formation. The Minawa Formation overlies the Koboke Formation. By the previous workers (KOJIMA, 1951; KOJIMA and MITSUNO, 1966), the schists in this area were divided into the "Oboke," "Kawaguchi," "Koboke" and "Minawa" Formations in ascending order. However, detailed field survey has revealed that the "Kawaguchi" Formation is interfingering with the "Koboke" Formation in the northern part of this area, and the "Koboke" Formation is traceable to the "Oboke" Formation. Therefore, the "Koboke" Formation is almost equivalent with the "Oboke" Formation, and they are rear-ranged into one formation, that is, the Koboke Formation. The schists in the southern part of this area form an E-W-trending anticline plunging eastward at low angle, which is the Oboke anticline (Ogawa, 1902). The axis of the Oboke anticline is cut by an ENE-WSW normal fault named the Oboke Fault near Hibihara, eastern part of this area.抄録全体を表示PDF形式でダウンロード (2169K) -
岩見沢団体研究グループ原稿種別: 本文
1984 年 38 巻 1 号 p. 64-66a
発行日: 1984/01/25
公開日: 2017/07/26
ジャーナル オープンアクセスPDF形式でダウンロード (1162K) -
日本の第四紀層の14C年代(151)木村 一朗, 三澤 寿美, 竹内 安江原稿種別: 本文
1984 年 38 巻 1 号 p. 67-69
発行日: 1984/01/25
公開日: 2017/07/26
ジャーナル オープンアクセスPDF形式でダウンロード (356K) -
日本の第四記層の14C年代(152)岩見沢団体研究グループ原稿種別: 本文
1984 年 38 巻 1 号 p. 70-71
発行日: 1984/01/25
公開日: 2017/07/26
ジャーナル オープンアクセスPDF形式でダウンロード (240K)
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