Study On The Origin Of Geothermal Water In The Gaoyang Low Uplift

The Gaoyang Low Uplift is located in the middle of the Jizhong Depression in the North China Plain,and geographically includes three areas:Gaoyang,Boye and Lixian.The thermal resources in the region are widely distributed and have abundant reserves.They have the advantages of shallow burial,high temperature,large drainage,and easy mining.At the same time,karst fractures are developed in the study area,and the fault structure is strong,and the mining and utilization value is large.However,the previous studies mainly focused on the geothermal fields in Rongcheng and Niutuo Town,and there were few analyses on the genetic mechanism of geothermal resources in the Gaoyang low uplift,especially in the Gaoyang and Boye areas with complex thermal storage structures of deep carbonate rocks.To explore the geochemical characteristics and formation mechanism of hot water,in order to deeply understand the formation mechanism of geothermal resources in the study area so as to develop and utilize geothermal resources scientifically,rationally and effectively in the later production and life,this paper takes the Gaoyang low uplift tectonic unit as the research The object,through field investigation,geothermal geology,hydrogeochemistry,isotopic characteristic analysis and other methods,analyzed the geothermal water geochemical characteristics and formation mechanism of the Gaoyang low uplift,and obtained the following understandings:（1）Different types of thermal reservoirs in the study area form different hydrochemical types due to the influence of tectonic movements,thermal properties of rocks,and water-rock interactions.The type is Cl·HCO₃-Na type,the hydrochemical type of Neogene sandstone thermal storage groundwater is Cl-Na type,and the groundwater mainly comes from the recharge of atmospheric precipitation in the western Taihang Mountains.According to the ¹⁴C isotope determination of the groundwater in the study area,the age of groundwater is about 13000-45000 years.（2）the heat of geothermal water mainly comes from the heat of the deep and upper mantle of the earth and the decay of radioactive elements in the shallow part of the crust.The under ground is heated by thermal convection with the deep bedrock and migrates dissolved pores,karst caves,fractures,stratigraphic unconformities and the Taihang Mountains piedmont fault system.Geothermal water with good exploration and development value.（3）The types of thermal storage include deep carbonate karst fracture-type thermal storage and Neogene sandstone pore-type thermal storage,among which the base rock thermal storage of the Wumishan Formation has deep burial,strong reducibility,high thermal conductivity and karst fractures.It is a good thermal reservoir in the study area due to its characteristics of development and easy migration of groundwater.The caprock is mainly Quaternary loose sediments,which have the characteristics of shallow burial,weak reducibility and low thermal conductivity,and can play a good role in thermal insulation.