1 0 0 0 OA 西太平洋伊豆・小笠原海域の海底熱水活動
- 著者
- 中尾 征三
- 出版者
- The Sedimentological Society of Japan
- 雑誌
- 堆積学研究会報 (ISSN:18844715)
- 巻号頁・発行日
- vol.31, no.31, pp.3-14, 1989-10-31 (Released:2010-05-27)
- 参考文献数
- 32
The Geological Survey of Japan has been conducting a study on submarine hydrothermal activity in the Izu-Ogasawara (or Bonin) Arc and the northernmost part of the Mariana Arc since 1984. Hydrothermal products, both unequivocal and inferred, are divided into three categories: 1) manganese or iron enriched sediments, and Mn-Fe hydroxide and silica deposits (chimneys) in the back-arc basin area; 2) manganese and/or iron oxide deposits occurring in the mountainous areas of both the back-arc and the volcanic front areas; and 3) a veinlet of iron-copper-zinc sulfides in hydothermally altered andesite on a wall of a submarine caldera along the volcanic front. This paper outlines these products as well as related geological, geophysical and geochemical data in the area.
1 0 0 0 OA 壱岐, 中新統勝本層に見られる背弧海盆堆積物の堆積相と堆積環境
- 著者
- 鬼頭 剛 坂井 卓 岡田 博有
- 出版者
- The Sedimentological Society of Japan
- 雑誌
- 堆積学研究会報 (ISSN:18844715)
- 巻号頁・発行日
- vol.38, no.38, pp.57-66, 1993-03-30 (Released:2010-05-27)
- 参考文献数
- 27
The Middle Miocene Katsumoto Formation, distributed in the northern and central part of Iki Island, Nagasaki Prefecture, has been considered as a typical back-arc basin sequence. This study aims to describe sedimentary facies, ichinofacies and paleocurrent system and to discuss sedimentary environments and depositional systems. The Katsumoto Formation, attaining more than 450m in thickness, shows a coarsening- and thickening-upward sequence as a whole. It begins with mud-dominated facies of interbedded sandstone and mudstone, passes upward into medium-bedded, medium-grained sandstone and siltstone facies, and ends with thick-bedded, medium- to coarse-grained sandstone facies at top. Six sedimentary facies recognized. Their lithologies are summarized as follows; Facies A: mainly well-sorted, medium to very coarse sandstone with planer to tabular cross-stratification, Facies B: well-sorted, very fine to medium sandstone with amalgamated hummocky cross-stratification (HCS), Facies Ca: interbedded HCS sandstone and siltstone, Facies Cb: thinly interbedded HCS sandstone and siltstone, Facies D: mottled sandy siltstone with thin very fine-grained sandstone, Facies Fa: slump breccia, Facies Fb: slump folded thinly interbedded sandstone and mudstone, and Facies F: interbedded very fine-grained turbidite sandstone and mudstone. The sedimentary environments inferred from Facies A to F are summarized as follows; Facies A: upper shoreface, Facies B: lower shoreface, Facies Ca and Cb: inner shelf, Facies D: outer shelf, Facies Ea: shelf margin, Facies Eb: continental slope, and Facies F: basin plain. Fossil evidence, such as burrowing organisms and benthonic foraminiferas obtained from the formation, seems to coincide with these environments. Eastward and northeastward paleoflows are dominant in the lower, and the middle and upper parts of the formation, respectively. It can be concluded, therefore, that the Katsumoto Formation represents a facies succession from basin plain to tide-dominated shallow marine sediments due to northeastward progradation process. The northeastward progradation system is also recognized in the regional area of the Tsushima Basin in the Middle Miocene time.
1 0 0 0 OA マンガン含有量と希土類元素パターンに基づく深海堆積物の成因的分類
- 著者
- 松本 良 薬袋 佳孝
- 出版者
- The Sedimentological Society of Japan
- 雑誌
- 堆積学研究会報 (ISSN:18844715)
- 巻号頁・発行日
- vol.21, no.21, pp.1-9, 1985-03-01 (Released:2010-05-27)
- 参考文献数
- 15
Manganese content of the deep sea sediments increases with decreasing the rate of sedimentation. This is interpreted as dilution of hydrogenous manganese, which accumulates at constant rate, by various amounts of terrigenous, biogenic and volcaniclastic materials. Deep sea sediments on and around the East Pacific Rise show strong negastive Ceanomaly, while brown clay and blue clay in the West, North and South Pacific show normal REE pattern.On the basis of the relation between Mn content and sedimentation rate, and the REE patterns (Ce anormaly and La/Yb ratio), deep sea sediments are classified into four types. They are 1) Type I, which deposits near land and is characterized by abundant terrigenous suites, 2) Type II, which deposits on abyssal plain very far from land and spreading center, 3) Type III, which deposits on and around active spreading ridge and is characterized by hydrothermal and volcaniclastic materials, and 4) Type IV, which deposits around active spreading ridge near land. Type IV is a mixed type of Type I and Type III.
1 0 0 0 大隅海峡周辺の表層堆積物中の重鉱物
Heavy mineral analyses were made for 18 samples of marine surface sediments in the Osumi Strait, south of Kyushu, Japan. Hypersthene is the most abundant, common hornblende, augite and olivine are next among the non-opaque minerals. The amount of heavy minerals is rich in the southwestern part of the Strait. There is a tendency to decrease in the total amount of heavy minerals and in specific gravity of bulk sediments northeastward. Surface sediments tend to become finer in the same direction. The current velocity necessary to move the sediment grain is changed with the specific gravity at the same grain size, because the grains with higher specific gravity are less mobile than the grains with lower specific gravity. It is considered that the grains are transported to the direction toward which the sediments become lighter in specific gravity and finer in grain size. Therefore, surface sediments distributed in the Osumi Strait are moved from southwest to northeast. This direction is concordant with the dominant current direction in the Strait. This means that the sediments are transported by the ocean current, the Osumi Branch Current, one of the branches of the Kuroshio flowing through the Strait and that the sediment distribution is highly influenced by the current.
1 0 0 0 OA 手製水路の作り方と実験例
- 著者
- 鈴木 一久
- 出版者
- The Sedimentological Society of Japan
- 雑誌
- 堆積学研究会報 (ISSN:18844715)
- 巻号頁・発行日
- vol.37, no.37, pp.85-92, 1992-11-01 (Released:2010-05-27)
- 参考文献数
- 3
- 被引用文献数
- 3
1 0 0 0 OA Vein structure
- 著者
- 小川 勇二郎 芦 寿一郎 中島 滋
- 出版者
- The Sedimentological Society of Japan
- 雑誌
- 堆積学研究会報 (ISSN:18844715)
- 巻号頁・発行日
- vol.34, no.34, pp.1-4, 1991-05-01 (Released:2010-05-27)
- 参考文献数
- 11
1 0 0 0 OA 沿岸地域における制約扇状地の性質
- 著者
- 武藤 鉄司
- 出版者
- The Sedimentological Society of Japan
- 雑誌
- 堆積学研究会報 (ISSN:18844715)
- 巻号頁・発行日
- vol.24, no.24, pp.13-18, 1986-04-20 (Released:2010-05-27)
- 参考文献数
- 10
1 0 0 0 OA 北海道白亜系函淵層群の堆積相と堆積シーケンス
- 著者
- 安藤 寿男
- 出版者
- The Sedimentological Society of Japan
- 雑誌
- 堆積学研究会報 (ISSN:18844715)
- 巻号頁・発行日
- vol.38, no.38, pp.45-52, 1993-03-30 (Released:2010-05-27)
- 参考文献数
- 22
The Hakubuchi Group is the uppermost unit of the Yezo Supergroup, a forearc basin sediment distributed along the meridional zone of Hokkaido, Japan. The group in the Sorachi Anticline represents the western marginal facies of the basin, showing conspicuous lateral facies changes. It is subdivided into three formations, Hk1, Hk2 and Hk3, based on the facies distribution. The upward shallowing succession of Hk1 and Hk2 in the eastern limb of the anticline, which is composed of inner shelf to delta plain facies through shoreface, foreshore and beach facies, is interpreted to be a lowstand delta on a conformable sequence boundary. The massive conglomerate facies constituting very thick Hk2 in the western limb and only the uppermost of Hk2 in the eastern limb, may be a transgressive systems tract. The base of the conglomerate in the wester limb corresponds to an erosional sequence boundary. A highstand systems tract is represented by Hk3 distributed widely in both limbs. The upper two parasequences of the three recognized in Hk3 had been partly eroded away under a sequence boundary (clinounconformity) with the Eocene coal measures, Ishikari Group. Therefore, the Hakobuchi Group constitutes a depositional sequence during 10m.y. (Lower Camapanian-Lower Maastrichtian).
1 0 0 0 OA 堆積環境指標としての炭質物中の黄鉄鉱
- 著者
- 鮎沢 潤
- 出版者
- The Sedimentological Society of Japan
- 雑誌
- 堆積学研究会報 (ISSN:18844715)
- 巻号頁・発行日
- vol.35, no.35, pp.77-81, 1991-11-01 (Released:2010-05-27)
- 参考文献数
- 19
A simple and practical method for estimating salinity is described in this paper based on pyrite (iron disulfide) content in carbonaceous materials by using a reflected microscope. The pyrite content is defined as the proportion of carbonaceous particles which contain pyrite in one hundred carbonaceous particles under microscope.The presence of pyrite in organic sedimentary rocks has been considered to be a result of sulfate from sea water, iron from hinterland, and carbonaceous materials as a reductant in coal swamp.Stratigraphic variations of pyrite content by this method were measured in four areas of Southwest Japan. The pyrite content in three Tertiary areas is in accordance with aquatic environments as previously reported. However, no correlation was observed between pyrtite content and estimated aquatic environments in the Omine coalfield where iron content varies considerably. This method will be employed as a useful tool to investigate sedimentary environments.
1 0 0 0 OA 地質学・土壌学・土質工学における粒径区分の比較
- 著者
- 満塩 大洸
- 出版者
- The Sedimentological Society of Japan
- 雑誌
- 堆積学研究会報 (ISSN:18844715)
- 巻号頁・発行日
- vol.22and23, no.22-23, pp.117-121, 1985-04-01 (Released:2010-05-27)
- 参考文献数
- 6
Comparison of grain size in the fields of geology, pedology, and soil engineering was made on viewpoints of 1) classification and names of each grain size, 2) mechanical grain analysis, and 3) method of each expression of the results of 2).These are quite different system in each field as are shown in Fig. 1. And therefore, much discussions and adjustments among them may be needed, even if each field has each own object.