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ID 21320
Eprint ID
21320
FullText URL
Title Alternative
Radioactive Anomaly in the Okutsu Kaoline Mine, Okayama Prefecture
Author
Okuno, Takahara
Watanabe, Koji
Abstract
奥津カオリン鉱床は花崗緑岩中の熱水交代性の塊状粘土鉱床であって, 中心部に白色粘土鉱体, それをとりまいて石英沸石帯,更にその外側に緑簾石帯からなる変質の帯状分布が存在する. 放射能異常は外側変質帯の緑簾石帯に集中しており, そこにトリウムの濃集が認められる. 本鉱床の放射性元素の濃集は変質帯形成の機構と密接に関連するものとみられる.
Abstract Alternative
The Okutsu Kaolin Mine. producing about 450 tons of clay a month, is located 25 Km north of Tsuyama, northern Okayama Prefecture. The massive hydrothermal clay deposits, present in granodiorite, is vertical1y and horizontally zoned. A white clay core, hal10ysite and hydrated halloysite, is surrounded by a laumontite-quartz zone. A epidote-quartz zone comes next and the outermost is a slightly altered granodiorite associated with epidote. The epidote-quartz zone is usually of radioactivity which is due to minor amounts of a reddish brown amorphous mineral, containg thorium. However, Uranium has never been detected in materials from the radioactive zone. The other zones are normal or low radioactivity. During hydrothermal alteration, the granodiorite changed to clay deposits and all the original components except Al(2)O(3) and TiO(2) were leached out. The leached CaO and Fe(2)O(3) were repricipitated around the deposits forming the epidote-quartz zone. The leached thorium behaved similarly with the two elements and waS concentrated together with them. The concept of the concentration of thorium discussed in this paper may help in solving questions on the alteration of the basal granite and the origin of radioactive elements in the neighbouring Ningyo Toge Uranium Fields.
Note
Original Papers
Published Date
1964-10-25
Publication Title
岡山大学温泉研究所報告
Publication Title Alternative
Papers of the Institute for Thermal Spring Research, Okayama University
Volume
volume34
Publisher
岡山大学温泉研究所
Publisher Alternative
Institute for Thermal Spring Research, Okayama University
Start Page
1
End Page
10
ISSN
0369-7142
NCID
AN00032853
Content Type
Departmental Bulletin Paper
language
日本語
File Version
publisher
Refereed
False
Eprints Journal Name
mmc