关中南部地下热水氢氧同位素组成的水文地质意义

Hydrogeology Significance on Hydrogen and Oxygen Lsotopes Composition in Underground Thermal Water of Guanzhong Area,Shaanxi Province

通过对关中南部地下热水氢氧同位素组成研究，探讨了研究区地下热水的起源、补给以及有关净热水的循环温度、循环深度、与冷水混合比例等与地下热水有关的热点问题，并与传统水文地质勘探方法进行了对比研究。氢氧同位素研究结果表明，研究区地下热水为净热水与常温水的混合，常温水混合量达半数以上。根据SiO2地热温标计算，净热水的热储温度为80℃～121℃，热储深度为1146．84～1779．38m。净热水的补给水源平均气温与现代降水平均气温相差约16℃。净热水的来源为第四纪末次冰期秦岭海拔1800m以上的冰川雪水。

Based on hydrogen and oxygen isotope study, the origin, recharge as well as the temperature, circulation depth and mixing proportion of geothermal waters in Guanzhong area were analyzed. Results showed the geo thermal water is the mixture of net thermal water and normal ground water. According to the calculated temperature of SiO2 geothermometer, the temperature and depths of geothermal reservoir for net geothermal water in the study area are estimated at about 80℃-121℃ and 1 146.84-1 779.38 m respectively. The hydrogen and oxygen isotope tracers and tritium dating show that the sources of geothermal water have certain relation with present day meteoric water. However, it is derived from meteoric water in the higher mountains area in the southern part of the area rather than from meteoric water in the local area.