著者
宮久 三千年 鹿島 愛彦
出版者
資源地質学会
雑誌
鉱山地質 (ISSN:00265209)
巻号頁・発行日
vol.17, no.84, pp.214-227, 1967

Dolomite deposits of western Shikoku are distributed in some definite stratigraphic and geotectonic zone. They are classified into the following group.<BR>1) Siliceous dolomite deposits of the northern zone of upper Carboniferous in age. These deposits are associated with red tuff, red chert, and other clastic sediments of volcanic materials.<BR>2) Some workable dolomite deposits of the southern zone of lower Triassic Uonashi formation, independent of volcanic activities.<BR>Chief factors of the formation of dolomite are temperature, pH, Eh and concentration of Mg-ion in the sea-water of geosynclinal basin. These factors are related to some paleogeographical environments, such as submarine volcanism (Northern zone) and development of shallow sedimentary basin of nearshore line (Southern zone).<BR>Chemical compositions of mineral dolomites, mechanism of dolomitization, deformation and recrystallization of ores, and relation of dolomite bed to other submarine sedimentary ore deposits are also discussed in this paper.
著者
田崎 耕市 高橋 治郎 板谷 徹丸 グレープス R.H. 鹿島 愛彦
出版者
日本鉱物科学会
雑誌
岩鉱 (ISSN:09149783)
巻号頁・発行日
vol.85, no.4, pp.155-160, 1990
被引用文献数
10

Many andesitic intrusions are exposed along the Median Tectonic Line (MTL) in northwestern Shikoku, Japan. Three dikes along the MTL and one intrusion occurring close to it were dated by the K-Ar method to estimate when the fault movement ceased. The dikes and intrusion are not deformed by the movement. The results give 15.1 to 15.4 Ma excluding severely altered one. The MTL in northwestern Shikoku region has not been active since about 15 Ma. Although a similar attenuation of active movement of the MTL during middle Miocene has been reported, the fault movement has continued in the other areas of southwestern Japan as demonstrated by Active Fault Research Group (1980). This may suggest that block displacement has been dominant since middle Miocene in the studied area. The age of the samples also indicates that the volcanic activity of Seto-uchi region started 15 Ma in northwestern Shikoku.
著者
漆原 和子 鹿島 愛彦 榎本 浩之 庫本 正 フランツ ディーター ミオトケ 仲程 正 比嘉 正弘
出版者
学術雑誌目次速報データベース由来
雑誌
地學雜誌 (ISSN:0022135X)
巻号頁・発行日
vol.108, no.1, pp.45-58, 1999
参考文献数
38
被引用文献数
2 3

Observations of the solution rate of limestone tablets from 1993 to 1997 have been utilized to clarify the degree of karstification from northern to southern Japan.<BR>Limestone tablets were placed at seven observation points stretching from northern to southern Japan : Toma, Abukuma, Chichibu, Akiyoshidai, Shikoku Onogahara, Ryugado, and Minamidaito. Three groups of four limestone tablets from Slovenia, Guilin (China), Chichibu, and the fourth tablet from limestone indigenous to the obsevation point, were arranged on three levels at each observation point : 1.5m above the ground, the A3 horizon, and the B<SUB>2</SUB> horizon. Measurements were taken of the solution rates of the tablets at each observation point from 1993 to 1997. Thornthwaite's method was used for calculating water balance to ascertain the relation between solution rate and water balance factors. The solution rates of limestone tablets placed 1.5m above the ground show a high correlation coefficient between (water surplus (WS) minus water deficit (WD)). On the other hand, limestone tablets planted in the soil had a solution rate from two to three times higher than those suspended in the air. The solution rates of limestone tablets located in the A<SUB>3</SUB> and B<SUB>2</SUB> horizons exhibited the highest annual precipitation correlation coefficient. The high CO<SUB>2</SUB>values under warm, humid conditions may account for the higher solution rates of the tablets planted in the soil.<BR>The solution rate tendency curve achieved its greatest range during the five years in direct proportion to the WS-WD ratio in 1993, when a cool, humid summer prevailed throughout most of Japan. The solution rate tendency curve marked its smallest range during the five years in proportion to the WS-WD ratio at all locations for limestone tablets suspended in air in 1994, under conditions of an extremely hot and dry summer, such as occurs only once in a hundred years. In general, however, the solution rates of the limestone tablets were high when the WS-WD ratio ranged between 1, 000 to 1, 600mm. Within this range, the solution rates at each observation point decreased slightly as the WS-WD ratio decreased.
著者
松尾 秀邦 高橋 治郎 鹿島 愛彦
出版者
愛媛大学
雑誌
一般研究(C)
巻号頁・発行日
1986

本研究によって新知見とすべき事項は下記の五項目である.1.岩湧寺植物群(Iwakiji Flora):伊藤大一(1986)により発見された. この化石植物群は白亜紀後期の植物群としては珍しい落葉樹林相を示す.2.Archaeojostera属について:郡場・三木(1931, 1958)によって新属とされた被子植物化石である. 一部の人々によって生痕化石説が唱えられているが, この化石の大半は植物化石である. しかし, 一部には生痕化石の疑いの残る部分もあって今後の研究が望まれる化石の一つである.3.鮮新世火成活動による変質:この現象は和泉砂岩層群の分布域の西端部で観察される. 鮮新世火成活動(主に含黒雲母安土岩, 石英安山岩など)によって, この地層の基部に近かい礫岩及び砂岩層が侵され, その硬度を増し, 割栗石その他の石材として採石されている.4.和泉砂岩層群の西端域について:この層群の地層の分布の西端部は愛媛県長浜町青島とされているが, その分布は対岸の大分県臼杵市近効大野川流域まで拡がる可能性がある. 化石こそ少ないが, 岩相の酷似が極め手となる. 今後の研究が望まれる.5.和泉砂岩層群の堆積構造について:これらの地層が堆積した後, 中央構造線を形成した地殻運動によって, 東西の曳きずりが働き, 南北性断層が発達している. これらの断層に区切られた6区の地域では, それぞれ東に落ちる向斜構造が認められる. この構造については, 和泉山脈西端部において松尾(1949)が始めて提唱し, それ以来幾多の研究者によって解明が試みられているが, 未だに説明できない構造の一つである.