Assessing the suitability of lithium-related geothermometers for estimating the temperature of felsic rock reservoirs

•Na-Li geothermometer provided by Michard (1990) is relatively suitable for fully equilibrated waters from felsic reservoirs.•The Na-Li ion-exchange equilibrium in thermal waters cannot be reached without a prior Na-K equilibrium.•Small measurement errors of Na and Li concentrations could bring about large deviations for Na-Li geothermometers.•The Li-Mg geothermometer is not recommended for estimating the temperatures of the felsic reservoirs. Lithium-related geothermometers are relatively rarely used because they are based on empirical relations derived from poorly known water-mineral equilibrium reactions and do not always give valid estimations. In this study, we evaluated the applicability of Na-Li and Li-Mg geothermometers based on hydrochemical data for geothermal waters from nine geothermal systems in felsic reservoirs in China. The results indicate that the Na-Li geothermometer provided by Michard (1990), which is similar to those given by Fouillac and Michard (1981) and Verma and Santoyo (1997) with Cl