《地球科学》(ISSN 1000-2383;CN42-1874/P) (原刊名《地球科学——中国地质大学学报》ISSN 1000-2383;CN42-1233/P)，创刊于1957年，是由教育部主管、中国地质大学主办的综合性地学学术理论期刊，月刊，2015年改名为《地球科学》,她以反映中国地质大学教学与科研最新的、高水平的基础地质、应用地质、资源与环境地质及地学工程技术研究成果为主要任务。

Xianxian geothermal exploitation area is one of the areas with the best occurrence conditions of geothermal resource in North China, rich in medium and low temperature geothermal resource, and is a typical carbonate geothermal field. However, its hydrogeochemical evolution process is not clear, and no complete conceptual model of geothermal genesis has been established to guide the exploration, development and utilization of geothermal resource in the area. It restricts the sustainable development of regional geothermal resource and the realization of carbon emission reduction targets. In this study, geothermal fluids in the area were collected for testing and analysis in terms of hydrochemical characteristics and stable isotopes. Based on systematic geochemical research, the formation mechanism of geothermal fluids was analyzed, and a conceptual model of geothermal genetic in the study area was established. The main understanding is as follows: the hydrochemical type of geothermal water in the study area is Cl-Na type, and the water-rock interaction is not balanced. The formation of geothermal water in the area is affected by the infiltration of atmospheric precipitation, and it is terrestrial leached water. The flow path of geothermal water is long, the water circulation is slow, and the metamorphism is deep. Dolomite, calcite and gypsum dissolution are the main sources of Mg²⁺, Ca²⁺, \({\text{HCO}}_{3}^{ - }\), and \({\text{SO}}_{4}^{{2 - }}\) in geothermal water, besides, other minerals containing calcium and magnesium are also part of their sources. The source of geothermal water recharge is atmospheric precipitation, and the recharge elevation of geothermal water is about 619–1069 m. The age of the geothermal water is between 16 000 and 18 000 years. The sulfur in geothermal water mainly comes from the leaching of sedimentary layer.

The Jiangnan orogenic belt is situated in the tectonic collision and convergence zone between the Yangtze Block and the Cathaysia Block. It represents a significant geological unit for the study of the tectonic evolution of South China. The region is situated at a plate convergence site, with favourable geothermal geological conditions and a plentiful supply of geothermal resources. However, the evolution process and heat source mechanism of geothermal water in the study area remain unclear, which impedes the exploration, exploitation and utilisation of deep geothermal resources and the realisation of the goal of carbon emission reduction. In this study, temperature measurements of geothermal wells and fine geotechnical thermophysical property tests were conducted. Terrestrial heat flow and heat fluxes at different depths were calculated, terrestrial heat flow characteristics of the area were identified, the blank area of terrestrial heat flow measurements was filled in, and geothermal water in the area was collected for tests and analyses of hydrochemical characteristic indexes and other aspects. In conjunction with the regional geological and tectonic background, the terrestrial heat flow and geothermal water chemistry in the study area were investigated. The source of heat and the formation mechanism of geothermal water in the study area were analysed, and the formation mode of geothermal resources in the central part of the Jiangnan orogenic belt was revealed. The results show that the measured terrestrial heat flow values of the geothermal boreholes in the study area are 79.68 and 88.31 mW/m², which are significantly higher than the average value of mainland China, indicating that there is an abundance of heat flow from the deep part of the earth to the surface in this area. The terrestrial heat flow values of the DR02 borehole show the distribution of high in the shallow part and low in the deep part, which suggests that the heat flow from the deep part of the earth in the study area is rapidly rising along the faults and then spreads in the shallow part, and it also suggests that new heat energy has been generated in shallow rock bodies. It also indicates that there is new thermal energy generation in the shallow rock body. The chemical types of geothermal water in the study area mainly include HCO₃ · SO₄–Na, HCO₃–Ca · Mg, and SO₄ · HCO₃–Na, and the water-rock interaction has not been balanced yet. The geothermal water in the study area is influenced by the infiltration of atmospheric precipitation in the process of formation, and is of terrestrial genesis. The reduction of geothermal water in the study area is not complete, and the thermal reservoir environment is poorly closed. The flow path of the geothermal water is shorter, the circulation is more efficient, the flow rate is faster, the water circulation is faster, and the degree of metamorphism is relatively shallow.