著者

宇野 泰章 寺西 清 礒村 公郎

出版者

日本鉱物科学会

雑誌

鉱物学雜誌 (ISSN:04541146)

巻号頁・発行日

vol.19, no.Special, pp.63-70, 1990-03-26 (Released:2009-08-11)

参考文献数

10

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The mode of occurrence of clay minerals and the interaction between hot waters and wall rocks in Arima and Takarazuka have been investigated by X-ray powder diffraction, microscopic observation and chemical analysis. The alteration halo can be divided into three zones, such as, zone I (chlorite-mica zone), zone II (silica zone) and zone III (mica-kaolinite zone). Low, medium and high-temperature waters are mainly located in zone I, II and III respectively. Calcite veinlets are present in drilling cores of zone I and II. The pH values of hot waters in zone II calculated on the basis of the calcite-brine equilibrium equations are higher than those in zone I. Partial CO2 pressure of hot waters are almost constant, indicating a 3.8 atmospheric pressure in zone I, and a 4.9 atmospheric pressure in zone II. The most important factor controlling the chemical composition of hot waters seems to be the calcite-brine equilibrium in wall rocks.