Nizhne-Shchapinsky thermal springs (Kamchatka) as an example of magnesium CO2-rich waters

Abstract

The results of hydrochemical studies of Nizhne-Shapinsky (Kipely) CO2-rich thermal (39 °C) springs in 2021 are presented. The springs discharge within the Shchapina graben near active Kizimen volcano. Results include macro- and trace-component composition, isotopic composition of spring water, some gas components and dissolved strontium. The results are discussed using previously published and reported data, taking into account the geological and structural setting of the area, water-rock interactions, and simple thermochemical calculations to explain the rare, but typical for the chemical composition of some CO2-rich waters, predominance of magnesium over calcium. It is shown that waters of Nizhne-Shchapinsky springs are formed as a result of mixing of two components: deeper and more heated sodium chloride water and more superficial, less heated water of Mg-Ca-HCO3- composition, formed due to interaction with carbonate-bearing rocks and CO2 of magmatic origin.

Keywords

• co2-rich thermal waters
• water-rock interaction
• shchapinsky graben
• kamchatka