Information on Geothermal System Obtained by Chemical and Isotopic Characteristics of Soil and Fumarolic Gases from the Doroyu-Kawarage Geothermal Field, Akita, Japan.
スポンサーリンク
概要
- 論文の詳細を見る
For soil gases from the Doroyu-Kawarage geothermal field in northern Japan, the concentrations of Rn, H<SUB>2</SUB>, CH<SUB>4</SUB>, CO<SUB>2</SUB> and rare gases (He and Ne) together with isotopic ratios of CO<SUB>2</SUB> and He (δ <SUP>13</SUP>C of C0<SUB>2</SUB> and <SUP>3</SUP>He/<SUP>4</SUP>He) were measured. In presently developing geothermal field to the northern part of Doroyu fault, Rn concentrations of soil gases are clearly higher than those to the southern part. On the other hand, the distribution of low δ <SUP>13</SUP>C values (-20∼-24‰) corresponds to that of Sanzugawaformation.This formation contains the organic matter underlying only to the northern part of the fault. However, higher δ <SUP>13</SUP>C values to the northern part, coexist with high concentration of H<SUB>2</SUB>. Soil gas samples from Kawarage and Doroyu geothermal manifestations contain high concentrations of Rn, H<SUB>2</SUB> and CO<SUB>2</SUB>, and the δ <SUP>13</SUP>C values also are extremely high. Therefore, it is inferred that CO<SUB>2</SUB> derived from a deep-seated geothermal system are added to those originated from organic matter in the Sanzugawa formation. These data indicate that the δ <SUP>13</SUP>C values of CO<SUB>2</SUB> can be useful in geothermal prospecting in addition to information provided by H<SUB>2</SUB> measurement. Soil gases from Kawarage and the vicinity do not give the high Rn concentrations, in spite of the high Hg concentrations. Such a fact may give the information on the alteration by the secondary hydrothermal water without U and Th, which is originated from the vaporization of deep-seated geothermal water. Furthermore, the <SUP>3</SUP>He/<SUP>4</SUP>He and <SUP>4</SUP>He/<SUP>20</SUP>Ne ratios of Kawarage fumarolic gas are 9.5×10<SUP>-6</SUP> and 180, respectively, indicating that the He is originated from magmatic gas. This fact is consistent with a consideration that the heat source of this geothermal field is the magma of the neighboring Quaternary volcanos such as Mt. Takamatsudake and Mt. Kabuto.
- 日本地熱学会の論文
日本地熱学会 | 論文
- 秋田県湯沢雄勝地域産流体包有物の研究 : 温度履歴と地熱流体の化学的性状
- 葛根田地熱地域における浅部貯留層の流体包有物のガス組成
- 低温溶液中のケイ酸の重合に及ぼす pH および金属陽イオンの影響について
- ダブルU字管型地中熱交換器の熱抽出特性
- シングルU字管型地中熱交換器の熱抽出特性