Abstract

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.

中文翻译：

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沧县隆起中部献县地热田地热流体地球化学特征及成因机制

摘要

献县地热开发区是华北地区地热资源赋存条件最好的地区之一，中低温地热资源丰富，是典型的碳酸盐地热田。但其水文地球化学演化过程尚不清楚，尚未建立完整的地热成因概念模型来指导该地区地热资源的勘探、开发和利用。制约了区域地热资源的可持续开发和碳减排目标的实现。本研究收集了该地区的地热流体，进行了水化学特征和稳定同位素的测试和分析。在系统地球化学研究的基础上，分析了地热流体的形成机制，建立了研究区地热成因的概念模型。主要认识为：研究区地热水水化学类型为Cl-Na型，水岩相互作用不平衡。该地区地热水的形成受大气降水的渗透影响，属陆地淋滤水。地热水流路长，水循环慢，变质深。白云石、方解石和石膏溶解是 Mg ²⁺、 Ca ²⁺、\({\text{HCO}}_{3}^{ - }\)和\({\text{SO}}_的主要来源地热水中的{4}^{{2 - }}\) ，此外，其他含有钙、镁的矿物质也是其来源的一部分。地热水补给来源为大气降水，地热水补给海拔约为619~1069 m。地热水的年龄在16 000至18 000年之间。地热水中的硫主要来自沉积层的淋滤。