ABSTRACT

Lithium as well as major chemical constituents, and stable hydrogen and oxygen isotopic ratios in 30 saline spring waters (Cl>5, 000 mg/l) in Japan were determined to clarify the genesis of the waters. The relationship between log (Na/Li) and the temperature estimated by geothermometers revealed that the lithium content of saline spring waters are not usually controlled at the present-day temperatures of the hydrothermal systems. Taking into account the values of the deviation coefficient of lithium to seawater, C_Li = (Li/Cl) sample/(Li/Cl) seawater, and the regions from which the spring waters were collected, the spring waters can be classified into the following four groups: Group 1, representing saline waters from coastal line (C_Li = 1.2–22), Group 2 those from greentuff region (C_Li = 17–110), Group 3 those from Osaka Basin (C_Li = 160–220), and Group 4 those from the outer part of Median Tectonic Line (C_Li = 250–440). The genetic features of the respective groups are discussed in detail.