氢氧稳定同位素的研究进展及在地热流体运移演化中的应用

Research progress on stable isotopes of hydrogen and oxygen and application on the geothermal fluid migration and evolution

地热流体作为地下水循环系统的重要组成部分,具有较强的经济价值和社会意义,而氢氧稳定同位素是认识水循环系统的重要信息指标,其组成特征可揭示区域内地热流体运移演化过程的规律变化,对掌握区域内地热流体补给来源,认清地热水循环路径具有重要作用,进而对合理开发利用保护地热资源提供理论支撑具有重要意义。现阶段,常利用丰度、同位素比值(R值)、千分偏差值(δ值)及氘盈余和17O盈余等变量来表示氢氧稳定同位素组成特征,并通过与标准品等参照物的比对,分析氢氧稳定同位素的变化规律及趋势,从而判断海洋水、大气水汽和降水、江河、湖泊水及地下水循环系统中氢氧稳定同位素区域性的演化分异特点,进而分析水循环系统所处温度、湿度、地质条件特征;明确其补给来源及补给比例;判断系统内水蒸发量、滞留时间等要素。而地热流体作为地下水循环系统的一部分,其氢氧稳定同位素的相关研究仍有不足,应加强针对地热流体氢氧稳定同位素的研究,认清其与区域内其他水循环系统的关系,同时注意引用新参数,应用新方法,并坚持开展长期持续性监测研究。

Geothermal fluid,as an important component of groundwater circulation system,has strong economic value and social significance.The stable isotopes of hydrogen and oxygen are the important information indicators for understanding the water cycle system.Their composition characteristics can reveal the regular changes in the migration and evolution process of geothermal fluids in the region.They play an important role in understanding the sources of geothermal fluid supply in the region,recognizing the geothermal water cycle path,and providing theoretical support for the rational development and utilization of geothermal resources,which is of great significance.At present,using abundance,isotope ratio(R value),thousand point deviation value(δvalue),d-excess and 17O-excess to represent the composition characteristics of stable isotopes of hydrogen and oxygen.By comparing with reference materials,analyze the variation patterns and trends of stable isotopes of hydrogen and oxygen,so as to judge the regional evolution and differentiation characteristics of stable isotopes of hydrogen and oxygen in marine water,atmospheric water vapor,precipitation,river,lake water and groundwater circulation system,and then analyze the temperature,humidity and geological conditions of the water circulation system;clarify the source and proportion of its supply;determine factors such as water evaporation and retention time within the system.However,as a part of the groundwater circulation system,there are still shortcomings in the research on the stable isotopes of hydrogen and oxygen in geothermal fluids.It is necessary to strengthen the research on the stable isotopes of hydrogen and oxygen in geothermal fluids,recognize their relationship with other water circulation systems in the region,and pay attention to introducing new parameters,applying new methods,and persistently conducting long-term and continuous monitoring research.