巻号一覧
121 巻, 5 号
選択された号の論文の3件中1～3を表示しています
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報告
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森 慎一, 高橋 直樹, 柴田 健一郎, 田中 裕一郎, 平田 大二, 大島 光春, 藤岡 換太郎2015 年 121 巻 5 号 p. 161-166
発行日: 2015/05/15
公開日: 2015/07/30
ジャーナル フリーVisual observations were conducted at the mouth of the Tokyo Submarine Canyon (TSC), at the junction of the TSC and the Misaki Depression, in August 2010, from the ROV Hyper-Dolphin. Examination of the topography and geology of the TSC and Miura Basin revealed four lithostratigraphic units in area, Units I to IV (in stratigraphically descending order). Unit I consists of Recent unconsolidated mud that thinly covers the bottom of the TSC and two deep-sea terraces. Unit II is a middle Pleistocene conglomerate observed at water depths of 1148-1096 m; the lithology and areal distribution of Unit II suggest deposition from a debris flow that surged down the canyon. Unit III is a middle Pleistocene semi-consolidated muddy deposit consisting of alternating horizontal beds of sandstone and mudstone, observed at water depths of 1120-809 m; Unit III is present throughout the Misaki Depression. Unit IV is a consolidated muddy deposit consisting of N-dipping alternating beds of sandstone and mudstone, observed at water depths of 1174-1120 m; the unit is partly eroded and is overlain by Unit II. The stratigraphic relationships and distributions of lithofacies at the mouth of the TSC help clarify the nature of tectonism in the area of the TSC and Miura Basin.抄録全体を表示PDF形式でダウンロード (4437K) -
Yuji Orihashi, Shunso Ishihara2015 年 121 巻 5 号 p. 167-171
発行日: 2015/05/15
公開日: 2015/07/30
ジャーナル フリーWe conducted U-Pb dating on zircon crystals separated from two drill core samples to ascertain whether a tonalite body discovered by drilling in Matsukawaura east of the Futaba Fault near the city of Soma, belongs to a 300-Ma Paleozoic granite, or to Cretaceous granitoids with age common to the Abukuma Highlands or the Kitakami Mountains. The zircons yield U-Pb ages of 115-114 Ma, which are slightly older than the age of Abukuma granitoids exposed to the area between the Hatagawa and Futaba faults (108-106 Ma). The Matsukawaura tonalite, having a typical adakitic signature, exhibits similarity to Cretaceous Takase Granite in Wariyama Sheared Granodiorite occurring along the east side of the Futaba Fault.抄録全体を表示PDF形式でダウンロード (1401K)
口絵
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赤羽 久忠, 清水 正明, 今井 裕之, 角田 謙朗2015 年 121 巻 5 号 p. V-VI
発行日: 2015/05/15
公開日: 2015/07/30
ジャーナル フリーPDF形式でダウンロード (2678K)
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