Isotope And Hydrochemical Evidence Of Genetic About Deep Geothermal Water

Carry out the research on the abdominal deep origin of geothermal water in guanzhong basin,which is a matter of the sustainable development and utilization ofgeothermal water,national economy and people's livelihood,low carbon environmental protection,which is of great significance to promote the rational development and utilization of the geothermal water in the western China.Therefore,use isotope hydrology geochemistry method in this paper and combine with the guanzhong basin tectonic evolution,carry on deep exploratory research on the different tectonic units in the studied area and the genetic evolution of geothermal water.Try to provide environmental isotope hydrogeochemical evidence of sedimentary characteristics and sedimentary water existence question.The genetic types of deep geothermal water of different tectonic units in the study area lead to the differences in isotope and hydrochemical features,in other words,the isotope and hydrochemical features of deep geothermal water of different tectonic units can infer the origin,the cause and the formation process in the geological history,and then be divided into different genetic types of geothermal water.We can initially determine the genetic types of geothermal water in the study area according to the isotope and hydrochemical features of deep geothermal water of different tectonic units in the study area,TDS,rNa/rCl,Cl/Br,SO42-×102/Cl and other genetic coefficients.We can identify the genetic type of geothermal water is modern lixiviation water,ancient lixiviation water or residual sedimentation water by the deviate degree of?2H and?18O,deuterium remaining and the value of 3H and 14 C,because that hydrogen and oxygen isotope of deep geothermal water in the study area are good indicators of the genetic evolution and storage environment.14C can identify the formation of geothermal water in different geologic time,and quantitate the retention time of geothermal water under ancient geological environment.The retention time of geothermal water in the study area is more than 10ka~2.9ka years,showing that it belongs to ancient water.The distribution range of 13 C and secondary hydrothermal calcite are overlap,showing that the main source of inorganic carbon in geothermal water is secondary hydrothermal calcite,or the formation time of geothermal water may be ahead of tectonic movement's period.The evolution of ?34S and ?18O in the SO42-of geothermal water shows that the process of bacteria reduction reaction,and provides the evidence about storage environment of geothermal water.The storage environments of Gushi Sag are more enclosed than Xianli Fault and Xi'an Sag,showing that the sulfate reduction reaction of Gushi Sag is strongest.According to the relationship between 3He/4He and 4He/ 20 Ne,identify the source of geothermal water vapor is mantle source,shell source or gas source and calculate the contribution proportion.The results of third yuan mixing ratio calculation show that geothermal water vapor of Xi'an Sag is affected by gas and shell source,and shell source influence is dominate;geothermal water vapor of Xianli Fault is affected by gas,mantle and shell source,and shell source influence is dominate;geothermal water vapor of Gushi Sag is not affected by gas source,and shell source influence is dominate,storage environment is enclosed.In conclusion,the results of isotope and hydrochemical show that geothermal water of different tectonic units have different genetic types.The genetic type of geothermal water in Xi'an Sag and west of Xianli Fault are the mixing of modern lixiviation water and ancient lixiviation water;the genetic type of geothermal water in east of Xianli Fault is ancient lixiviation water.The geothermal water of Gushi Sag contains residual sedimentation water.