Study On Hydrogeochemical Characteristics And Genesis Of Underground Hot Water In Gongjue Region,Tibet

The study area is located in Awang Township,Gongjue County,Changdu District,eastern Tibet.It is located in the tropical zone of Yunnan-Tibet Plateau.The area has developed structures,strong hydrothermal activities,and good geothermal geological conditions.However,controlled by the harsh natural environment and inconvenient traffic conditions,there are few reports on the geothermal research in this area.In order to meet the local demand for geothermal resources,it is necessary to strengthen the research on the cause mode of the underground hot water in the area and improve it.The conceptual model of the genetic model of underground hot water provides scientific suggestions for future geothermal resource development or engineering construction.We take the underground hot water exposed in Awang Township as the research object,and combines the existing data in the research area to conduct a field investigation on the geological and hydrogeological conditions in the research area.Field surface cold water was tested on site parameters and water samples were collected,and the hydrochemical area chemistry method and isotope analysis method were used to obtain the water chemistry type,recharge source and thermal storage temperature,circulation depth and mixing ratio of cold water in the geothermal system Et al.Established the genetic model of the geothermal system in the study area.The research results show that the study area is located at the junction of the Yangtze block and the Qiangtang-Sanjiang block,in the west of the Jinshajiang suture zone.The tectonic activity in the area is intense,and the tectonic direction is mainly NNW.The stratum has been cut to varying degrees.Among them,the Nina Gumba-Ratu fault formed a thrust and overthrow with the fault,which exposed the Carboniferous strata and cut the Neogene strata to the south,which provided good channel conditions for the upward migration of underground hot water.Affected by the stratum and structure,the temperature of the underground hot water in the area is 56.7?72.5?,the temperature of the surface cold spring and surface water in the area is 5.5?12.2?,the type of water chemistry is from the cold water supply area to the hot water discharge area from HCO₃-Ca type and HCO₃-Mg·Ca type evolved into HCO₃-Na type.The source of underground hot water replenishment in the study area is atmospheric precipitation,and a slight oxygen drift has occurred.The recharge elevation is between 4600-4900m and the residence time is between33034a-39045a.The strontium isotope characteristics indicate that the thermal storage of underground hot water is Carbonate rock layer and aluminosilicate formation;the temperature of shallow thermal reservoir and deep thermal reservoir calculated by geochemical temperature scale are 110.3?118.8?and deep thermal reservoir 170.7?177.9?,It is estimated that the depth of underground hot water circulation in the study area is about 4500?5300m.Respectively,using silicon enthalpy equation method and silicon enthalpy The proportion of cold water mixed by graphic method is between 59.6%and 70.3%.In summary,the genetic model of the geothermal system in the study area was analyzed,and a conceptual model of the geothermal water genetic model was established to provide a scientific basis for the development and utilization of geothermal resources and engineering construction in the research area.