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Geoscience ›› 2025, Vol. 39 ›› Issue (02): 429-439.DOI: 10.19657/j.geoscience.1000-8527.2023.056

• Monitoring, Modeling and Assessment of Supergene Resources • Previous Articles     Next Articles

Hydrochemistry and H-O Isotopic Constraints of Geothermal Fluids in the Guantao Formation in the Eastern Hebei Plain: Implications for Geothermal Reservoir Dynamics

XU Yiming1,2(), LI Aoyu3, CHENG Liqun1,2(), DU Lixin4, ZHANG Yanshuai5, HAO Wenhui1, LIU Liang1   

  1. 1. The Eighth Geological Brigade of Hebei Bureau of Geology and Mineral Resources Exploration,Qinhuangdao,Hebei 066000,China
    2. Hebei Baodi Construction Engineering Corporation,Ltd,Qinhuangdao,Hebei 066000,China
    3. China National Geological & Mining Corporation,Beijing 100029,China
    4. The Seventh Geological Brigade of Hebei Bureau of Geology and Mineral Resources Exploration,Xiong’an,Hebei 071700,China
    5. School of Water Resources and Environment,China University of Geosciences(Beijing),Beijing 100083,China
  • Online:2025-04-10 Published:2025-05-08
  • Contact: CHENG Liqun

Abstract:

The Neogene Guantao Formation geothermal reservoir in the Eastern Hebei Plain represents a clastic porous layered heat reservoir characterized by superior geothermal geological conditions. To facilitate the scientific conservation and rational utilization of these geothermal resources, this study presents comprehensive analysis of the chemical and H-O isotopic compositions of 16 geothermal water samples collected from various geological units within the Eastern Hebei Plain. Experimental results reveal that the primary hydrochemical types of the Guantao Formation geothermal water are HCO3· SO4-Na, HCO3·Cl-Na, SO4·Cl-Na, with pH values ranging from 7.78 to 8.62 and salinity levels between 722.3 and 2619 mg/L. The geothermal water exhibits elevated concentrations of F-, SiO2, TDS, Sr, Zn, Br, I, Fe, Mn, and HBO2. However, concentrations of certain elements associated with magmatic hydrothermal activities (such as F, B, As, Li, etc.) are significantly lower compared to those found in Yangbajing and Dagejia in Tibet. H-O isotopic analysis indicates δD values ranging from -71‰ to -73‰ and δ18O values from -7.6‰ to -9.8‰, suggesting a recharge elevation of 800 to 1300 meters. The geothermal water primarily flows from northwest to southeast, with minimal interaction with overlying shallow strata water. It is predominantly recharged by lateral flow within the same layer and the upward migration of Ordovician hot fluids from the Paleozoic erathem, classifying it as deep-circulation heated groundwater. Atmospheric precipitation from the Yanshan area percolates downward along fault structures under gravitational force, flowing southeastward. As the groundwater is progressively heated by deep crustal thermal sources, water-rock interactions intensify, leading to a significant increase in mineral content. With increasing circulation depth and distance, the geothermal water environment becomes more confined, resulting in a gradual reduction in water renewal rates. Desulfation processes occur within the geothermal water, which also mixes with underlying deep geothermal fluids, altering the primary ion composition. This study provides a scientific foundation for understanding the formation and evolution of geothermal water in the Guantao Formation.

Key words: hydro-geochemical characteristics, isotopic characteristics, geothermal, Guantao formation, eastern Hebei Plain

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