著者

志岐 常正

出版者

地学団体研究会

雑誌

地球科学 (ISSN:03666611)

巻号頁・発行日

vol.22, no.5, pp.240-250, 1968

被引用文献数

1

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In this article, genetic relations between various types of " graywackes " were investigated synthetically. Several properties which have been pointed out by many workers as the characteristics of "graywackes ", and their meanings, were cited first. Several concepts such as provenance factor, textural and mineralogical maturity, mechanism of transportation (fluidity factor), and " three critical environments of deposition" mentioned by RICH, were summarized in their mutual relations, The origin of variety of "graywackes" was then explained successfully using the above concepts or ideas as shown in the schematized models of Figure 4. Post depositional alteration or diagenesis was mentioned in connection with the origin of clay matrix of graywackes.

著者

清水 大吉郎

出版者

地学団体研究会

雑誌

地球科學 (ISSN:03666611)

巻号頁・発行日

vol.31, no.5, pp.228-234, 1977-09-25

著者

大森 昌衛

出版者

地学団体研究会

雑誌

地球科学 (ISSN:03666611)

巻号頁・発行日

vol.1954, no.18, pp.16-23, 1954

著者

坂井 一 黒川 勝己

出版者

地学団体研究会

雑誌

地球科学 (ISSN:03666611)

巻号頁・発行日

vol.56, no.4, pp.217-230, 2002

参考文献数

32

被引用文献数

4

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魚沼層群のSK110と上総層群のKd25火山灰層,およびSK100とKd24火山灰層の対比を検討した.これらの火山灰層はいずれも黒雲母の目立つガラス質火山灰層である.SK110とKd25およびその広域対比が指摘されている火山灰層については,記載岩石学的特徴や火山ガラスの化学組成から対比が検証され,さらにSK110とKd25とは,黒雲母の化学組成(Mg#=41.8-43.6)も一致する.SK100とKd24の対比については,火山ガラスに多孔質型が多いことや,化学組成の一致,有色鉱物に少量の褐れん石を含む共通性から対比できると考えられる.またSK100とKd24の黒雲母の化学組成(Mg#=26.0-36.0)も類似の組成範囲にある.なおSK100とKd24の火山ガラスや黒雲母,斜方輝石は,SK110やKd25に比べて,より低いMg#値を示す.SK100やKd24は,今後より広い地域にわたって見出されることが期待される.

著者

ウルルン島地質調査団

出版者

地学団体研究会

雑誌

地球科學 (ISSN:03666611)

巻号頁・発行日

vol.56, no.3, pp.141-143, 2002-05-25

著者

鈴木 尉元

出版者

地学団体研究会

雑誌

地球科学 (ISSN:03666611)

巻号頁・発行日

vol.58, no.2, pp.127-130, 2004-03-25 (Released:2017-07-14)

著者

鈴木 尉元

出版者

地学団体研究会

雑誌

地球科学 (ISSN:03666611)

巻号頁・発行日

vol.59, no.5, pp.329-334, 2005-09-25 (Released:2017-07-14)

著者

田沢 純一

出版者

地学団体研究会

雑誌

地球科学 (ISSN:03666611)

巻号頁・発行日

vol.57, no.5, pp.315-318, 2003-11-25 (Released:2017-07-14)

被引用文献数

4

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Middle Permian brachiopod fauna of the South Kitakami Belt is characterized by the mixture of both the Boreal and Tethyan elements. In the Middle Permian, the area having the Boreal-Tethyan mixed brachiopod fauna is restricted in the northern to eastern outer margin of North China (Sino-Korea), i. e., the Inner Mongolian-Japanese Transitional Zone. The South Kitakami area was probably part of a continental shelf bordering the northern to eastern margin of North China. The geographical distributions of two Boreal elements, Yakovlevia mammata (Keyserling) and Spiriferella keilhavii (von Buch), and a Tethyan element Leptodus nobils (Waagen) are summarized and illustrated.

著者

周琵琶湖花崗岩団体研究グループ 橋本 勘 久田 義之 沓掛 俊夫 中野 聰志 西橋 秀海 西村 貞治 澤田 一彦 杉井 完治 多賀 優 竹本 健一 天白 俊馬 吉田 源市

出版者

地学団体研究会

雑誌

地球科学 (ISSN:03666611)

巻号頁・発行日

vol.54, no.6, pp.380-392, 2000

参考文献数

22

被引用文献数

6

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田上花こう岩体(東西方向約20km×南北方向約8km)は,後期白亜紀末の"琵琶湖コールドロン"形成に関わった環状花こう岩体のうちで最も南に位置する.田上花こう岩体は,粒度と組織から4つの岩相に区分される(中〜粗粒黒雲母花こう岩,中〜粗粒斑状黒雲母花こう岩,細〜中粒斑状黒雲母花こう岩,細粒黒雲母花こう岩).田上花こう岩体は,丹波帯のジュラ紀付加コンプレックスと新期領家花こう岩と考えられる観音寺花こう閃緑岩に貫入している.観音寺花こう閃緑岩を含む岩体の北西部に貫入している花こう斑岩岩脈は,雁行状配列を示している.同じく岩体の北西部では,湖東流紋岩類に属すると考えられる珪長質火砕岩を捕獲または伴う石英斑岩岩脈が産する.これらの岩脈群は,"琵琶湖コールドロン"形成時の環状割れ目を充填しているものと考えられる.主要・微量元素全岩化学組成上,観音寺花こう閃緑岩は田上花こう岩とは異なる特徴を持つ.岩脈類も,微量元素組成の点で田上花こう岩類とは異なり,特に石英斑岩は湖東流紋岩類の秦荘石英斑岩に似ている.田上花こう岩は,琵琶湖南部周辺の花こう岩類と密接な成因的な関係を有する.

著者

河田 清雄

出版者

地学団体研究会

雑誌

地球科学 (ISSN:03666611)

巻号頁・発行日

vol.1966, no.84, pp.6-13, 1966-05-30 (Released:2017-07-25)

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The pre-Tertiary igneous rocks, hitherto taken for "quartz porphyries" after the former prevailing conception, was revealed by the writer's reexamination, to be the altered pyroclastic deposits characterized by the rhyolite welded tuff, and was newly named "Okunikko rhyolites." The petrographical characteristics and mode of occurences in the field were described in the present articles. Most of the eruptions are considered to have taken place along the sheared zone of N-S trend within the basement composed of the upper Paleozoics. The rhyolites were intruded and thermally metamorphosed by the late Cretaceous granites. The age of the rhyolites is supposed, judging from the similarity with the igenous activity of Cretaceous age in the Inner Zone of Southwest Japan, to be Cretaceous likewise. The original areal extension is approximately estimated at 1,400 km2, and the former total volume might be not less than 1,000km3.

著者

大嶋 和雄 斎藤 文紀

出版者

地学団体研究会

雑誌

地球科学 (ISSN:03666611)

巻号頁・発行日

vol.47, no.3, pp.213-231, 1993

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Tokyo Bay is badly polluted, but would be in much worse shape were in not for sewage treatment and regulation. Such management techniques for water quality have rid the bay of toxic mercury sludge, and have made the average water quality of the bay head up to Class C rating, which indicates no unpleasant effects on everyday life. The bay still yields fishery products; a 30,000-ton catch in 1990. However, its yield is less than only a third of the maximum of the past fisheries yield. There is a limit, however, to technology. To bring the water quality rating of the entire bay up to Class B, suitable for fishing, would require that treated sewage dumped into the bay be able to support marine life. The construction of sewage treatment plants to perform such a feat would be prohibitively expensive, and the cost of the treatment would be a continuing liability, not a one-time fix. In other words, though technology can keep death at bay, it alone cannot restore Tokyo's coastal area to health. A Tokyo-Bay restoration project must harness the area's natural ability to recover from environmental damage. That recovery is accomplished through three mechanisms; sea-water exchange, sedimentation, and biological production. The coast is the interface between land and sea, where its ecosystem has developed over thousand of years. Technology works to fight pollution, but only to a point. Coastal restoration projects must be designed to work with the powerfull cleaning system of the bay itself if they are to assist truly sustainable development.

著者

杉山 明

出版者

地学団体研究会

雑誌

地球科学 (ISSN:03666611)

巻号頁・発行日

vol.60, no.5, pp.441-447, 2006-09-25 (Released:2017-07-14)

著者

小林 武彦

出版者

地学団体研究会

雑誌

地球科学 (ISSN:03666611)

巻号頁・発行日

vol.33, no.6, pp.ii-iib, 1979

被引用文献数

1

著者

塩野 敏昭

出版者

地学団体研究会

雑誌

地球科学 (ISSN:03666611)

巻号頁・発行日

vol.69, no.5, pp.289-292, 2015-09-25 (Released:2017-05-12)

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Some facilities of the Fukushima Daiichi Nuclear Power Station (NPS) have been constructed on the reclaimed land. According to the disaster photos disclosed by the Nuclear and Industrial Safety Agency (NISA) and the Tokyo Electric Power Company, Incorporated (TEPCO), the damage caused by the earthquake motion was found at the facilities of water supply, drainage, and power supply systems. As a result, it is presumed that leakage paths of the contaminated water become complicated. To examine countermeasures against the contaminated water issues, it is indispensable to investigate the seismic damage of the reclaimed land and the facilities by the earthquake motion in detail to clarify the leakage paths of the contaminated water.

著者

青木 三郎 生沼 郁

出版者

地学団体研究会

雑誌

地球科学 (ISSN:03666611)

巻号頁・発行日

vol.27, no.1, pp.35-39, 1973

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日本海山陰沖大陸棚上33地点から得たドレッヂ試料中に含まれている粘土鉱物をX線回折法によって調べた.2μ以下の部分に含まれている粘土鉱物は,モンモリロナイト,クロライト,イライトおよびカオリナイトである.イライトはすべての試料中でもっとも優勢な鉱物であり,その平均含有量は54%である,クロライト,カオリナイト,モンモリロナイトの平均含有量は,各々24, 12, 11%である.研究海域の粘土鉱物組成は,東シナ海堆積物のそれによく似ている.このことは,東シナ海から当海域を通って日本海北部へ流れる対馬暖流が運搬する細粒物質が,当海域の堆積物中の粘土鉱物組成に反映していることを暗示している.モンモリロナイトの含有量が相対的に少いのは,おそらく当海域への火山物質の供給が少いためと思われる.

著者

大森 昌衛

出版者

地学団体研究会

雑誌

地球科学 (ISSN:03666611)

巻号頁・発行日

vol.58, no.4, pp.256-259, 2004-07-25 (Released:2017-07-14)

著者

林 成多

出版者

The Association for the Geological Collaboration in Japan

雑誌

地球科学 (ISSN:03666611)

巻号頁・発行日

vol.53, no.1, pp.38-52, 1999-01-25 (Released:2017-07-14)

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埼玉県南西部の加治丘陵および入間川流域に分布する鮮新-更新統の上総層群から産出したネタイハムシの化石について再検討を行った.その結果,仏子層(前期更新世)からはオオミズクサハムシPlateumaris constricticollis,ブシミズクサハムシPlateumaris dorsata,フトネクイハムシ近似種Donacia cf. clavareaui,フトネクイハムシ亜属の1種Donacia(Donaciomima)sp.,コウホネネクイハムシ近似種Donacia(Donacia)cf. ozensis,イネネクイハムシ亜属の1種Donacia(Cyphogaster)sp.の6種を確認した.また,仏子層の下位層である飯能礫下部層(後期鮮新世)からもオオミズクサハムシとフトネクイハムシ近似種が産出した.仏子層および飯能礫層から産出したネクイハムシの化石には,後期鮮新世から前期更新世のネクイハムシ相には現生種と絶滅種の両方が含まれていることを示している.さらに,関東地方の各地から報告された中期更新世と後期更新世のネクイハムシの化石には現生種のみが含まれており,より古い時代の後期鮮新世から前期更新世のネクイハムシ相とは種構成が異なっている.絶滅種とされるブシミズクサハムシは仏子層から記載されたミズクサハムシ属の1種である.原記載以降,本種の系統関係を推定する上で重要ないくつかの形質が観察された.本種は近縁種のヒラシマミズクサハムシPlateumaris weiseiとの共通祖先から前期更新世以前に旧北区東部で分化し,北米に分布する姉妹種のP. germariは本種から派生した種であることが,これら3種の新たに得られた系統関係,化石記録,地理的分布から推定される.

著者

林 成多

出版者

The Association for the Geological Collaboration in Japan

雑誌

地球科学 (ISSN:03666611)

巻号頁・発行日

vol.51, no.5, pp.361-370, 1997-09-25 (Released:2017-07-11)

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埼玉県入間市野田の入間川河床において,仏子層のA部層より多くのネクイハムシ亜科の化石が得られた.これらの化石を検討した結果,ほとんどの化石はミズクサハムシ属の1種に同定された.この種は,前胸背板の表面を網目状の微細彫刻が覆い,不明瞭な中央縦溝を持つなどの特徴により,ミズクサハムシ属の現生種とは区別され,絶滅した未記載種である.本論では,仏子層A部層産のミズクサハムシ属の1種を新種Plateumaris dorsata, sp. nov.ブシミズクサハムシ(新称)として記載し,本種のミズクサハムシ属における分類学的な位置づけについて考察した.

著者

沼沢団体研究グループ

出版者

地学団体研究会

雑誌

地球科学 (ISSN:03666611)

巻号頁・発行日

vol.53, no.1, pp.53-70, 1999-01-25 (Released:2017-07-14)

被引用文献数

3

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福島県会津の西部に位置する沼沢火山はカルデラ湖を持つ小火山で,中期更新世後期(約13万年前)に噴火を開始した.噴火の最終段階で形成されたカルデラ湖の長軸は,鮮新世に形成された古いカルデラの長軸と一致している.沼沢火山の火山層序は下位より惣山溶岩,水沼火砕岩層,水沼層,大栗山溶岩,51kaに噴出した早戸火砕岩層,5000年前に噴出した沼沢火砕岩層および沼沢層の7つのユニットに区分される.惣山溶岩は普通輝石-シソ輝石デイサイト(SiO_2 63-68%)から成る.水沼火砕岩層は火砕流堆積物から成り,流紋岩質(SiO_2 75%)で,黒雲母を含んでいる.大栗山溶岩は黒雲母-ホルンブレンドデイサイト(SiO_2 65%)から成る.早戸火砕岩層は溶岩,溶結凝灰岩および火砕流堆積物から構成されている.デイサイト質(SiO_2 68-70%)で,黒雲母,ホルンブレンドおよびカミングトン閃石を含んでいる.沼沢火砕岩層もデイサイト質(SiO_2 65%)であるが,シソ輝石やホルンブレンドを含んでいる.火砕流堆積物で構成されており,安山岩マグマとデイサイトマグマの混合で形成された縞状軽石も含んでいる.水沼層と沼沢層は河川成の礫層から構成されている.沼沢火山の岩石化学組成は,東北日本第四紀火山の森吉火山帯のものと似ている.

著者

赤木 三郎

出版者

地学団体研究会

雑誌

地球科学 (ISSN:03666611)

巻号頁・発行日

vol.1958, no.38, pp.13-27, 1958-06-28 (Released:2017-07-24)

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In this paper, the writer discussed the significance of the growth and form of fusulinids, especially of the relations between such shell forms as cylindrical or fusiform and the spiral growth of the shell. Most of the materials, used in this study, are chosen from the specimens of Pseudoschwagerina miharanoensis AKAGI (MS), collected from the limestone of Miharano, Tojo-machi, Hiba-gun, Hiroshima Prefecture. It is the most abundant fusulinids in the Miharano Limestone (Sakmarian). The fossils occur as free specimens detouched from matrix, so that the external characteristics are well observed. First, the meanings of the shell form were discussed. Geometrically, the mode of growth is regular and rather simple, in spite of the apparent complexity of the internal structures exhibited in thin sections. An increase of protplasm results the growth of body and the coiling chambers. Additions of chambers along the preceding ones make up the volutions, which are performed regularly, because their floors and backside walls are substituted by the corresponding roofs and frontal walls of the preceding ones. Organization has not been studied in fusulinids. They have been included in the "Anaxonia" together with such higher invertebrates as gastropods and others, as was the case of the other members of Amoebae. But, it should be better to remove them from the Anaxonia, because they have a distinct axis in their bodies, around which the shell is formed in a certain regular and definite way of coiling, whereas the members of true Anaxonia do not show any regularity in their organization. So, the writer proposes a new group "Spiralia" for those animals characterised by the spiral organization of body. Second, the spiral curves of coiling were studied in some detail, and were compared with curves drawn geometrically. In this case, the writer found that the spiral curves of fusulinids were nearly identical with logarithmic spiral, which was characterized by a constant angle of tangent against the corresponding radius at their contact. Such spirals as those are called equiangular spirals. The angles of contact in Pseudoschwagerina miharanoensis are about 86 degrees throughout the most stages of growth, except the earliest and the gerontic stages. A deployed figure is drawn in such a way as follows : First, an ideal cross section is deduced from an axial section. In this operation, the law of constant angle of contact is used. The ideal cross section is better than a real cross section for the prepareation of a deployed figure, because it represents a cross section of the same individual from which the axial section is obtained. Further, an ideal cross section confirms the specific identity of a real cross section and the axial section, from which the ideal cross section is deduced. The spiral curve of the ideal cross section, is, then, unrolled and straightened in a straight line. Then, the chambers of the axial section are figured serially and successively on the straight line, where the positions of each chamber are located so as to equal to the lengths of corresponding half a volutions. Next, both ends of each sections were connected successively by lines on both sides of the figure. The figure, thus obtained, represents an unrolled sheet of a fusulinid indvidual, and it, really, shows the mode of growth very clearly. The deployed figure of Pseudoschwagerina miharanoensis, deduced from the holotype specimen, shows that the rate of growth changes rapidly in several stages. Also, it shows the relation between growth and form, the increase of tunnel angles and the relative growth of several parts of shell. The growth of the shell in spiral direction is larger in the center, and becomes smaller toward the polar regions. From such deployed figures of fusulinids, followings are noticed. 1. In fusnlinids, four factors of growth are important in the study of shell form. These(View PDF for the rest of the abstract.)