Conceptual model of the formation of nitrogen thermal waters in crystalline rock massifs (example of the Kuldur Spa)

The study of the inﬂuence of hydrodynamic factors on the occurrence of nitrogen thermal waters in crystalline massifs, by the example of the Kuldur ﬁeld, is presented in the article. The results of two-dimensional modeling (based on FEFLOW code) of several variants of formation and circulation of therms in the study area are considered. Model parameters included temperature (130–140 °C), calculated on the basis of geothermometers, and the residence time of waters in the rock massif (68 800–254 000 years), estimated by means of 14C and 4He dating. The modeling results show that exactly the ﬁltration parameters of the granite massif are the main factor controlling the dynamics of ﬂuid movement and, consequently, the relative age of thermal waters. It is also found that the ﬁltration characteristics of the fault zone have a signiﬁcant inﬂuence on the temperature of thermal water discharge.