Thermal groundwater resources were found to have occurred in deep-seated bedrock aquifers in the northeastern North China plain near Tianjin, China. Meso- to Neo-Proterozoic and Paleozoic carbonate rocks on the Cangxi...Thermal groundwater resources were found to have occurred in deep-seated bedrock aquifers in the northeastern North China plain near Tianjin, China. Meso- to Neo-Proterozoic and Paleozoic carbonate rocks on the Cangxian uplift are capable of yielding 960-4 200 m 3/d of 60 to 96 ℃ water from the wells ranging in depth between 1 000 and 4 000 m. Conductive heat flow of 0.063 to 0.144 2 W/m 2 from the deep crust is responsible for this anomalous geothermal field. The water in the Ordovician aquifer is characterized by relatively high TDS, high concentrations of SO 4 and SO 4·Cl-Na·Ca type, but the waters from the Meso- to Neo-Proterozoic and Cambrian aquifers, by relatively low TDS, low concentrations of SO 4 and predominantly Cl·SO 4-Na type. It is noted that when the temperature of the waters increases at a rate of 10 ℃ in the range of 30-100 ℃, the content of SiO 2 increases at a rate of 12 to 15 mg/L, and fluoride concentration increases at a rate of 2.3 to 2.5 mg/L. Hydrochemical and isotopic data suggest that the thermal water in the bedrock aquifers is of meteoric origin and recharged in the northern mountain area to the north of the Baodi-Ninghe fault, and then flows laterally for a long distance from the north to the south to the city of Tianjin. Temperature of the waters increases because of heat exchange with the rocks and recharge by conductive heat flow from beneath.展开更多
Statistical study of analyses of water from 43 samples from geothermal wells,three groundwater wells,and one sample of local rainwater along with rainwater data from the Global Network of Isotopes in Precipitation has...Statistical study of analyses of water from 43 samples from geothermal wells,three groundwater wells,and one sample of local rainwater along with rainwater data from the Global Network of Isotopes in Precipitation has been used to identify the origin and evolution of geothermal water in the Niutuozhen(牛驼镇)geothermal field and estimate the renewability rate of its geothermal resource.The results show that the geothermal waters of the Jixianian Wumishanian dolomite reservoir and the Ordovician limestone reservoir are of Cl-Na type,the geothermal water of the Pliocene Minghuazhen(明化镇)Formation sandstone reservoir are Cl-Na type and HCO3-Na type and the groundwater of the Quaternary aquifer is HCO3-Na and HCO3-Na·Mg·Ca type.A linear relationship between silica concentration and temperature indicates that higher temperature probably enhances concentration of silica in Jixianian geothermal water.δ18O shift in Wumishanian geothermal water averaged1.57‰,and was less than 1‰in the other geothermal waters.The minimum and maxi-mum14C ages of Wumishanian geothermal water are 17 000 and 33 000 years from north to the south of the Niutuozhen geothermal field.Geothermal water and Quaternary groundwater belong to different groundwater systems with no hydraulic connections.Although the geothermal field receives some recharge from the Yanshan and Taihang mountains outside the northern and western boundaries of the geothermal field respectively,the renewability rate of geothermal water is on the scale of 10 000 years.展开更多
基金ThisworkisfundedbytheMinistryofEducationofChinafortheKeyProjectsofScienceandTechnologyResearch (No .0 2 0 2 6)
文摘Thermal groundwater resources were found to have occurred in deep-seated bedrock aquifers in the northeastern North China plain near Tianjin, China. Meso- to Neo-Proterozoic and Paleozoic carbonate rocks on the Cangxian uplift are capable of yielding 960-4 200 m 3/d of 60 to 96 ℃ water from the wells ranging in depth between 1 000 and 4 000 m. Conductive heat flow of 0.063 to 0.144 2 W/m 2 from the deep crust is responsible for this anomalous geothermal field. The water in the Ordovician aquifer is characterized by relatively high TDS, high concentrations of SO 4 and SO 4·Cl-Na·Ca type, but the waters from the Meso- to Neo-Proterozoic and Cambrian aquifers, by relatively low TDS, low concentrations of SO 4 and predominantly Cl·SO 4-Na type. It is noted that when the temperature of the waters increases at a rate of 10 ℃ in the range of 30-100 ℃, the content of SiO 2 increases at a rate of 12 to 15 mg/L, and fluoride concentration increases at a rate of 2.3 to 2.5 mg/L. Hydrochemical and isotopic data suggest that the thermal water in the bedrock aquifers is of meteoric origin and recharged in the northern mountain area to the north of the Baodi-Ninghe fault, and then flows laterally for a long distance from the north to the south to the city of Tianjin. Temperature of the waters increases because of heat exchange with the rocks and recharge by conductive heat flow from beneath.
基金supported by the National Basic Research Program of China(No.2010CB428806)Beijing Municipal Science and Technology Project(No.D07050601510000)
文摘Statistical study of analyses of water from 43 samples from geothermal wells,three groundwater wells,and one sample of local rainwater along with rainwater data from the Global Network of Isotopes in Precipitation has been used to identify the origin and evolution of geothermal water in the Niutuozhen(牛驼镇)geothermal field and estimate the renewability rate of its geothermal resource.The results show that the geothermal waters of the Jixianian Wumishanian dolomite reservoir and the Ordovician limestone reservoir are of Cl-Na type,the geothermal water of the Pliocene Minghuazhen(明化镇)Formation sandstone reservoir are Cl-Na type and HCO3-Na type and the groundwater of the Quaternary aquifer is HCO3-Na and HCO3-Na·Mg·Ca type.A linear relationship between silica concentration and temperature indicates that higher temperature probably enhances concentration of silica in Jixianian geothermal water.δ18O shift in Wumishanian geothermal water averaged1.57‰,and was less than 1‰in the other geothermal waters.The minimum and maxi-mum14C ages of Wumishanian geothermal water are 17 000 and 33 000 years from north to the south of the Niutuozhen geothermal field.Geothermal water and Quaternary groundwater belong to different groundwater systems with no hydraulic connections.Although the geothermal field receives some recharge from the Yanshan and Taihang mountains outside the northern and western boundaries of the geothermal field respectively,the renewability rate of geothermal water is on the scale of 10 000 years.
