西南喀斯特流域岩溶水氢氧同位素时空分布特征及水文意义--以后寨河流域为例  

Spatiotemporal Features of Deuterium and Oxygen-18 in Karst Water and Its Relation to Hydrological Regime in the Karst Catchment of Southwest China--A Case Study of Houzhai Catchment

作　　者：张艳青 张志才[1,5] 陈喜 王刚 程勤波[1] 刘皓[1] 彭韬[4,5] ZHANG Yanqing;ZHANG Zhicai;CHEN Xi;WANG Gang;CHENG Qinbo;LIU Hao;PENG Tao(College of Hydrology and Water Resources,Hohai University,Nanjing 210098,China;Institute of Surface-Earth System Science,Tianjin University,Tianjin 300072,China;College of Water Conservancy and Civil Engineering,Shandong Agricultural University,Tai'an 271000,China;State Key Laboratory of Environmental Geochemistry,Institute of Geochemistry,Chinese Academy of Sciences,Guiyang,550002,China;China Ecosystem Research Network,Puding Karst Ecosystem Observation and Research Station,Chinese Academy of Sciences,Puding Guizhou 562100,Ghina)

机构地区：[1]河海大学水文水资源学院,南京210098 [2]天津大学地球系统科学学院,天津300072 [3]山东农业大学水利土木工程学院,山东泰安271018 [4]中国科学院地球化学研究所,环境地球化学国家重点实验室,贵阳550081 [5]中国科学院普定喀斯特生态系统观测研究站,中国生态系统研究网络,贵州普定562100

出　　处：《地球与环境》2022年第1期25-33,共9页Earth and Environment

基　　金：国家自然科学基金项目(41971028、42030506);国家重点研发项目(2016YFC0502602)。

摘　　要：受多重导水介质影响,喀斯特流域水循环过程复杂,只以水分为研究对象的水文学方法难以刻画其时空变化特征及其受喀斯特水文地质条件的控制作用。稳定氢氧同位素赋予岩溶水指纹信息,为解译喀斯特流域水循环时空演变与水文功能提供了重要研究手段。论文选取贵州普定后寨河流域为研究对象,基于月尺度的高空间分辨率的水样采集,结合聚类分析和.克里金插值方法,分析流域岩溶地下水氢氧同位素和反映蒸发分馆程度的Lc指数时空分布特征及其影响因素。以此为基础,研究喀斯特流域降雨混合、水文连通性及水流路径等水文作用。结果表明,研究区雨季岩溶地下水δ^(18)O与Lc偏负,枯季岩溶水整体δ^(18)O与Lc相对偏正,表明雨季湿热条件下,岩溶地下水受“新”、“老”水混合作用与流域蒸发过程的共同影响,枯季地下水混合作用较弱,蒸发作用弱;相较于中下游覆盖型涪溶区,流域上游峰丛区岩溶水δ^(18)O偏负,Lc偏正,表明流域上游土壤/表层岩溶带浅薄山区,降雨入渗迅速,岩溶水中土壤水成分较低,下游土壤较厚,入渗较慢且蒸发强烈,地下水蓄存时间长,岩溶水中土壤水成分较高。干湿交替期,岩溶水Lc快速变负,表明随水文连通性增强,土壤水补充岩溶含水层地下水能力增强。Affected by multiple media,the hydrological processes in karst catchment are complicated.Hydrological methods using only water as the research object are difficult to characterize the spatiotemporal features in water cycle and its controlling factor of karstic hydrogeological conditions.As a kind of fingerprint of water flow,the deuterium and oxygen-18(δ^(18)O)provide a potentially useful information for exploring the hydrological processes and hydrological functions in karst-catchment.In this study,the hydrological functions,such as flow mixing,hydrological connection and flow paths,were explored using stable isotopes analysis in a karst catchment of Houzhai in Puding,Guizhou Province.High spatial resolution sampling was carried out at monthly steps in this catchment.The dynamics of δ^(18)O and Line-conditioned index(Lc)reflecting the degree of evaporative fractionation,as well as its controlling factors in karst water were analyzed using cluster and Kriging interpolation methods.The results show that δ^(18)O in karst water in the dry season are more enriched than that in the wet season,meanwhile,the Lc in karst water for dry season is higher than that in wet season.The strong evaporative effect on the karst water in wet season reveals the mixing of"new"water(rainfall)with the"old"water stored in soil,while the karst water has weak evaporative effect due to the less mixing with soil water.Compared to the mid-downstream area,the depleted g180 and higher Lc in karst water in upstream area with thin soil cover indicate the strong rapid infiltration of rainfall results in the low proportion of soil water in karst water.In contrast,the karst water in mid-downstream area with long residence time has a high proportion of soil water.During the midpoint of dry and wet season,enhanced hydrological connection leads the increase in soil water recharge to karst water.

关 键 词：氢氧同位素 Lc指数 水文作用 喀斯特流域 

分 类 号：P641.3[天文地球—地质矿产勘探]