TIME VARIATION OF COMPOSITION OF WATER AND GASES AND OF ISOTOPIC DISTRIBUTION IN CO2 AND CH4 IN THE DZHETY-OGUZ MINERAL SPRINGS (ISSYK-KUL' SEISMIC ZONE)

Abstract

We report on the time-dependent variations in the water-gas system of the Dzhety-Oguz mineral springs, located in the large Terskey fault zone, as well as on response of some properties of that system to the M = 6.3 Tyupsk earthquake on March 25, 1978. There exists a significant time variation in composition of the natural gases of the Dzhety-Oguz thermomineral springs apparently caused by nonuniform mixing of thermal waters and gases originating at different crustal depths in the Terskey seismic fault zone. The latter is confirmed by significant spontaneous variation in isotopic composition of carbon in CH4 and CO2, associated with decreases of helium content in the gases with a simultaneous increase in CH4 concentration.