Volcanic Baths

Thermae are hot springs , widely distributed in the areas of modern and modern ( Pliocene - Quaternary ) volcanism . Not all terms are associated with volcanoes , as temperature increases with depth, and in areas with a high geothermal gradient, the circulating atmospheric water is heated to high temperatures.

Hot springs of volcanic regions, for example, in Yellowstone Park in the USA , Italy , New Zealand , Kamchatka , and the Caucasus , have a variable composition of water and different temperatures, since groundwater mixes in different proportions with volcanic gases and react differently with the host rocks. through which they seep into the depths. The waters are sodium chloride, acid sulfate-chloride, acid sulfate, sodium and calcium bicarbonate and others. Thermal waters often contain many radioactive substances, in particular radon .

Hot water changes surrounding rocks, depositing iron oxides and sulfides in them and changing them to clay , which turns into boiling mud ( Pauzhetka , Kamchatka ), where numerous gurgling “cauldrons” with reddish mud with a temperature of about +100 ° C are known. Often deposits of silicon scale or tuff accumulate around the sources, and if water contains calcium carbonate , lime tuff is deposited.