Abstract

The results of the hydrogeochemical study of poorly mineralized thermal groundwaters from the Kuldur Spa (Jewish Autonomous Region, Russia) are reported. These groundwaters are distinguished by their high temperature (73°С), low TDS (up to 0.38 g/L), and alkaline environment (pH 9). The dominant cation is sodium, and the dominant anion is hydrocarbonate. The waters are enriched in fluorine, silicon, aluminum, tungsten, molybdenum, and several other anionic elements. Detailed data on the chemical and mineral composition of water-hosting (intrusive) rocks are provided and the sources of the major brine components in the groundwaters are revealed. The study of the associated gases shows that the major component of the gaseous phase (N₂) is atmogenic, while CH₄ and CO₂ are biogenic. Argon and oxygen are derived from air as well, whereas helium is predominantly of the radiogenic crustal origin. The isotope characteristics of oxygen and hydrogen in the aqueous phase indicate the undoubtedly meteoric genesis of the groundwater with an extended circulation period. The results suggest that the thermal groundwaters of the spa are formed via penetration of meteoric waters to a depth of 4 km and heating to 100 °C. The dissolved chemical elements that form the brine phase come via the dissolution of host rocks; however, since the groundwater circulates within the rocky massifs of poorly soluble granitoids, respectively, the TDS of the groundwater remains low.

中文翻译：

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Kuldur Spa（俄罗斯犹太自治区）的氮热地下水的化学和同位素组成

摘要

据报道，来自Kuldur Spa（俄罗斯犹太自治区）的矿化度差的热地下水的水文地球化学研究结果。这些地下水的特点是高温（73°С），低TDS（最高0.38 g / L）和碱性环境（pH 9）。主要的阳离子是钠，主要的阴离子是烃。这些水富含氟，硅，铝，钨，钼和其他几种阴离子元素。提供了有关含水岩（侵入性）岩石的化学和矿物成分的详细数据，并揭示了地下水中主要盐水成分的来源。对伴随气体的研究表明，气相（N ₂）的主要成分是气态的，而CH ₄和CO ₂是生物成因的。氩气和氧气也都来自空气，而氦气主要来自放射性地壳。水相中氧和氢的同位素特征无疑表明了地下水具有延长的循环周期的陨石成因。结果表明，温泉的热地下水是通过流经深达4 km的陨石水并加热到100°C形成的。形成盐水相的溶解化学元素来自于主岩的溶解。但是，由于地下水分别在可溶性差的花岗岩类岩石质块中循环，因此地下水的TDS仍然很低。