Rare-earth elements in salt lakes of Southeastern Transbaikalia

Abstract

It was shown that with increasing salinity of waters, it was determined that concentrations of dissolved heavy HREEs and medium MREEs increase in soda lakes. It was determined that sulfatreduction and secondary mineral formation can influence the migration of lanthanides in lakes. Sulfatreduction leads to accumulation of lanthanides of medium MREEs and heavy HREEs subgroups in lake waters. The content of lanthanides of the light LREE subgroup is controlled mainly by secondary mineral formation. Thermodynamic calculations show that the degree of saturation in parasite CaCe0.95La0.6Nd0.35Pr0.1(CO3)3F2 and bastnesite CeCO3(OH)F is higher in soda lakes than in chloride lakes. The saturation of lake waters with respect to cerium hydroxide III in anaerobic and cerium hydroxide IV in aerobic conditions leads to the formation of negative cerium anomaly in lake waters of the considered lake types. It is shown that the different nature of the formation of soda and chloride lakes is the main reason for different concentrations of REEs in their waters and bottom sediments.