The Geochemistry of Rare Earth Elements in Natural Waters and Secondary Mineral Sediments of Thermal Fields of Kamchatka

The distribution of rare-earth elements in surface and underground waters, water-bearing rocks, and secondary mineral neoformations of thermal waters of the Paratunka and Vilyuchinsk hydrothermal systems of Kamchatka has been studied. It is revealed that their content, distribution, and fractionation differ with respect to the geochemical type of water and the pH-Eh of the aquifer. All waters are characterized by the domination of the transportation of dissolved rare earth elements, which exceeds their transportation with colloids by 1000 times. It has been shown that neoformations of carbonates, sulfates, and silicates, including calcite, gypsum, and amorphous opal, are widespread in the discharge areas of the studied thermal waters. The redistribution intensity of rare earth elements in the rock-water-secondary deposits system is very low in waters of the sulfate type, where the elements are bonded to sulfates. At the same time, the precipitation of rare earth elements as newly formed mineral phases is most intensive in water with carbonate complexes.