このエントリーをはてなブックマークに追加
ID 21194
Eprint ID
21194
FullText URL
Title Alternative
Stable isotope study of the hotsprings and volcanoes of Hokkaido, Japan
Author
Matsubaya, Osamu
Sakai, Hitoshi
Ueda, Akira
Tsutsumi, Makoto
Kusakabe, Minoru
Abstract
Stable isotope ratios of hydrogen, oxygen, carbon and sulfur of precipitation, thermal and mineral waters, and volcanic gases were measured. The isotopic data combined with chemical and geological information were discussed in terms of origin and evolution of the hotsprings and volcanic gases. The hotsprings along the Uchiura Bay, Oshima Peninsula are mostly near-neutral NaCl-type thermal water and may be divided into three groups : (1) thermal waters isotopically similar to the precipitation of this area, (2) those similar in D/H to the local meteoric waters but enriched by 2 to 3‰ in (18)O compared to the latter, and (3) those enriched significantly in both D and (18)O relative to the local meteoric waters. The first and second types of thermal water probably form from local meteoric water which percolates through "Green Tuff" formations and acquires dissolved chemicals from them. However, high salt concentration and the oxygen isotope shift (thesecond type) may imply that the NaCl-type water of volcanic origin might be involved. On the other hand, the waters of the third group can be explained by mixing of modern sea water into the second type thermal water (in case of Yachigashira) or by incorporation of fossil sea water of Tertiary origin into modern meteoric water (Nigorigawa). Except for Esan, Noboribetsu and Atosanupuri volcanic systems, waters from all the hotsprings and volcanic fumaroles associated with Quaternary volcanic rocks are meteoric in origin. Thermal waters at Esan, Noboribetsu and Atosanupuri have δD = -30~-50 and δ(18)O = -1~+ 3‰ and are enriched in D and (18)O relative to local meteoric water of the respective area. The origin of these waters and the mechanism (s) controlling the isotope ratios could not be made clear by the present study. Interesting is the finding that at Esan, Noboribetsu and Atosanupuri, thermal waters are enriched in D and (18)O relative to near-by fumarolic gases. The enrichment factor is 18 to 26‰ for hydrogen and 4 to 6‰ for oxygen, implying that more than one stages of liquidvapor separation are taking place in underground hydrothermal systems.
Note
原著論文 (Original Papers)
Published Date
1978-03-25
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
volume47
Publisher
岡山大学温泉研究所
Publisher Alternative
Institute for Thermal Spring Research, Okayama University
Start Page
55
End Page
67
ISSN
0369-7142
NCID
AN00032853
Content Type
Departmental Bulletin Paper
language
日本語
File Version
publisher
Refereed
False
Eprints Journal Name
mmc