© 2015 Elsevier Ltd. The hot springs of the Pymvashor subarctic hydrothermal system are of considerable interest because the area is devoid of recent volcanism and is located in the permafrost region. We attempted to evaluate the activity of thermal waters with respect to host rocks to quantify the water residence time in this system and date the associated travertine. Therefore, we used the chemical composition of the thermal waters, thermodynamic modeling, δ¹⁸O and δ²H labels and isotopes, such as ¹⁴C-δ¹³C, ²³⁴U-²³⁸U, and ²³⁰Th-²³²Th. The δ¹⁸O and δ²H values indicated the infiltration of atmospheric water in the recharge area of the hydrothermal system and suggested a stable paleoclimate in the area over the last 5-7.9 thousand years. The fresh water flows through deep parts of the aquifer system where it mixes with brine followed by discharge. The hot springs geothermal water total dissolved solid