Geochemical characteristics of Na-Ca-Cl-HCO3 type waters in Arima and its vicinity in the western Kinki district, Japan.

Rare Earth Elements and Sr-Nd-Pb Isotopic Analyses of the Arima Hot Spring Waters, Southwest Japan: Implications for Origin of the Arima-type Brine

“…Our sample water is visibly colorless, implying that it is less oxidized and has a lower propensity to precipitate the solutes. Kusuda et al [23] have analyzed "Ginsuiso Kinsen" sample (which is the same brine with "Kinsen", although the sampling date is different), 12 solute elements/ components and isotopic ratios of H, He, C, O: e.g., ~40000 mg/L Cl, ~20000 mg/L Na, 51.0 mg/L Li, δ 18 O=5.0‰, δD=-34.1‰, which is close to the estimated "deep brine" composition on the tritium-free basis [21][22][23].…”

“…The optimized data to the analyzed abundance by a mixing among slab-derived fluid and river water are listed in the "Mixed fluid" row. In any case, deep brine must mix with the near-surface water, as evidenced by δ 18 O-δD-tritium systematics [20][21][22]. In Figure 6, we estimate a best fit composition of fluid that mixes a slab-fluid (that consists of a mixture of AOC-derived fluid (Figure 5b) and sediment-derived fluid (Figure 5c) and the river waters in the Rokko Mountains ( Figure 5d) [41].…”

“…In the Arima area, the brines seem to upwell through ATTL and the subsidiary faults [35], with at least seven hot spring sources, i.e., Ariake, Gosha, Gokuraku, Kinsen, Tansan, Tenjin, and Uwanari. These hot spring waters exhibit a wide compositional range, which can be explained by mixing of two types of meteoric waters and a "deep brine" component [21,22]. The deep brine component is characterized by high solute concentrations (i.e., high Na, Cl, K, etc.…”

“…Within this context, the Arima-typebrine, which is a type of non-volcanic hot spring water with high chlorine content (~40000 ppm) and oxygenhydrogen isotopic ratios similar to magmatic/metamorphic thermal waters [20], has been argued to have originated from deep-seated brine [20][21][22]. The Arima-type brine may provide in valuable information concerning a slab-fluid in a fore-arc region where no magmatic information is available [23,24].…”

Geochemical implication of the lithium content of saline spring waters in Japan.

“…Figures 3 and 4 indicate that the waters from the Arima Takarazuka-Ishibotoke area are formed by the mixing of meteoric waters with the unique high saline water having fairly high CU value (about 200). Although the formation mechanism of the saline springs of this area has been debated extensively (Miyake et al, 1954;Tsurumaki, 1964;Matsubaya et al, 1973;Matsubaya et d, 1974;Tanaka et al, 1984;Masuda et al, 1985), no decisive conclusion as to the origin of the unique saline brine has yet to be drawn. The fact that the CLi values of Arima and Takarazuka (located on the northern rim of the Osaka basin) are similar to that of Ishibotoke (on its southern rim) is consistent with the hypothesis that the brine waters of the Arima-Takarazuka-Ishibotoke area were formed in marine sediments of the Osaka basin and were later trapped into faults and cracks developed by the continuous uplift of the Rokko and Ikoma mountains and sub sidence in the central area since the middle Pliocene (Sakai and Matsubaya, 1977).…”