蔵王山麓の湧泉に関する地球化学的研究

抄録

Zao volcanic group is well known for its activity which has often taken place in the historic time. In the surrounding area, poisonous acid waters are found here and there. They are represented by Zao and Kamoshika hot-springs, the Su-kawa River and the Zao River. The studies on these have been made already by the author from the geochemical point of view. Meanwhile, the literature on the springs flowing out at the foot of this volcanic group has never been published. In such a circumstance, he has made the geochemical survey of these springs since 1963. In this paper, the chemical quality of the waters and the regional features of these are presented in detail. The Su-kawa mud flow formed by the ancient eruption of Ryu-zan volcano is subjected to the solfataric action even at the present time. Therefore, the waters of the springs there are characterized by high contents of calcium and sulfate ions. The same is the case with the total evaporation residue. In addition, among the springs in question, only this group belongs to sulfate type spring while the others are of bicarbonate type.
Regarding the quality-of-water, the springs in the Kanno mud flow area are compared stochastically with those in Mt. Yokokura-yama area. As for the chloride, bicarbonate, calcium and sodium ions, the mean concentration of the former group is always higher than that of of the latter. Different from this, in the case of sulfate ion the latter has a larger mean content. Moreover, the seasonal difference of dissolved ingredients is examined stochasticaly with the springs of the two areas mentioned above. Common to the two areas, the concentrations of calcium and chloride ions are higher in August than in November. Reverse is the case with sulfate and bibarbonate ions.