Geochemistry of Thermal Waters of Continental Margin of Far East of Russia

Abstract

Studied waters belong to warm (T=30–50°C), alkaline (pH=8.9–9.3), low mineralized (TDS<235 mg/l) Na–HCO3 or Na–SO4–HCO3 thermal waters with high content of SiO2 (up to 81 mg/l) and F (up to 3.9 mg/l), occur on modern volcano–tectonic rejuvenated areas of Eastern Sikhote–Alin orogenic belt. Low 3He concentration as well as N2/O2 and N2/Ar ratios exclude influence of deep mantle fluid. New rare earth element data constrain our understanding of water–rock interaction occurring in the water source region. Meteoric origin of waters is proved by stable isotope values varying from −71‰ to −136.1‰ and from −10.8‰ to −18.8‰ for δ2H and δ18O respectively. REE patterns reflect high pH, resultfing from water–rock interaction and oxidative conditions. Calculations of deep aquifer temperature using Na–K and quartz geothermometers show 116.8–131.1° C and 82.2–125.8°C respectively. Presence of deep faults both with abnormal thermal gradient (∼45–50 K/km) define unique geochemical shape of thermal waters of Sikhote–Alin, area, where no present volcanic activity is registered.

Geochemistry and Formation Conditions of the Ulsk Thermal Spring, the Okhotsk Sea Coast, Khabarovsk Territory

“…Пробы для анализа на стабильные изотопы (δ 18 (N 2 = 91-94 объем. %), на втором месте находится кислород (2.5-6.5 объем.…”

“…Проявления термальных вод, локализованные на побережье континентальной части юга Дальнего Востока России, привлекают большое внимание широкого круга специалистов [3,8,13,14,18], однако вследствие их отдаленности от крупных населенных пунктов и труднодоступности остаются слабоизученными.…”

Hydrochemistry of thermal waters in crystalline rocks of the Sikhote-Alin ridge, Far East of Russia

“…Thermal waters occur in the contact zone between effusive (quartz porphyry) and tuffaceous sedimentary rocks of the upper Cretaceous age in the Bolbinskaya and Tatarkinskaya suites. The granites of Palaeogene age intrude these rocks [5].…”

“…Some groups of springs (Annensky, Tumninsky, Amgu, Chistovodny and Ulsky) are used by locals as spa for self-treatment. During the last two decades the geochemistry of these groups of springs has been studied [2][3][4][5][6]. Here we present the hydrochemical data for 5 groups of thermal springs of the Sikhote Alin Ridge combined with the analysis of geological and tectonic settings and discuss factors and processes controlling the origin of these waters.…”

Hydrogeochemistry of thermal waters of the Baikal Rift, South-Eastern Tuva, Russia

“…A large number of the thermal waters in Russia are concentrated in Kamchatka, Primorye, Caucasus, Baikal and the Rift Zone (BRZ). Among the variety of thermal waters are allocated Na-НСО3 thermal waters or nitrogen/soda thermal waters [5][6][7]. Distinctive features of Na-НСО3 thermal waters are low total dissolved solids (overwhelmingly up to 1 g/L), almost exclusively the sodium composition of the cations, a high temperature, the alkaline reaction and the dominant nitrogen (N2) in gas composition.…”