Modeling of physical and chemical interactions in system "water – granite" in conditions of a nitrogen term formation is held. It is established, that Clarke’s contents volatiles in rock can generate the concentration of the main anions corresponding to their contents in natural terms, but at higher, rarely meeting size of mineralization of thermal waters. Modeling solutions, which mineralization there corresponds to widely widespread types a nitrogen term in crystal rocks, have HSiO3-Na composition. By careful field researches it is established, that Tien-Shan nitrogen terms have hydrosilicate sodium composition. Clark’s concentration of nitrogen can provide its receipt in a solution in the quantity providing half of its contents in an atmospheric precipitation or spring waters of a intensive water exchange zone. The high helium concentration established in granites of the base of the Siberian platform, form solutions, in which its contents correspond to contents in wide common types a nitrogen term water. Concentrating of solutions is process not characteristic for a nitrogen term formation.