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

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
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

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
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

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

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)

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

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
森 伸一
出版者
地学団体研究会
雑誌
地学教育と科学運動 (ISSN:03893766)
巻号頁・発行日
no.5, pp.65-68, 1976-10-08

今年の3月まで6年間,伊豆半島南西部,東海道線三島駅からバスで3時間かかる静岡県立松崎高校に勤務し地学を教えた.松崎高校は1学年6クラス270名(女子の方が少し多い男女共学の普通校)で1年生全員が地学を2単位で履修した.