| 高寒干旱区地表水与地下水水化学特征及转换关系:以大通河流域为例 |
| 摘要点击 2621 全文点击 2728 投稿时间：2022-04-20 修订日期：2022-05-16 |
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| 中文关键词 地表水 地下水 水化学特征 氢氧稳定同位素 转化关系 大通河流域 |
| 英文关键词 surface water groundwater hydrochemical characteristics oxygen and hydrogen isotopes transformation relationship Datong River Basin |
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| 中文摘要 |
| 全球气候变暖和区域极端气候会导致高寒干旱山区平原降雨失衡、冰川融化和冻土退化，进而改变区域水文循环.其中，地表水与地下水转化关系是高寒干旱区水文循环气候响应的重要科学问题之一.以祁连山南麓大通河流域为研究区，基于119组基本水化学参数和38组氘氧同位素数据，利用多元统计分析和同位素技术，研究了流域地表水与地下水的水化学特征及其相互转化过程.结果表明，流域地表水以HCO3-Mg·Ca型水为主，受控于岩石风化作用；地下水以HCO3-Mg·Ca型和Cl·SO4-Na型水为主，受岩石风化作用和蒸发浓缩共同控制.上游地下水存在少量钙、镁长石的溶解，中游地下水化学组分主要为碳酸盐岩的风化溶解，下游地下水中各离子组分蒸发富集使地下水溶解性总固体升高.风化溶滤、人为活动、原生沉积环境、阳离子交替吸附及其他因素对研究区地表水和地下水化学组分的贡献率依次为39.1%、15.0%、12.6%、13.8%和19.5%.δD和δ18 O同位素测试结果表明，沿地下水流向大通河河水氘氧同位素含量呈富集到贫化的变化趋势，大通河上、中游地区河水主要受大气降水补给，而下游河段受地质构造和水文地质条件等影响，主要为潜水和泉水溢出补给河水，为地下水排泄区. |
| 英文摘要 |
| Global warming and regional extreme climates will lead to unbalanced rainfall, melting glaciers, and permafrost degradation in alpine and arid mountain plains, thereby changing the regional hydrological cycle. The relationship between surface water and groundwater conversion is one of the important scientific issues of hydrological cycle climate response in alpine arid areas. Taking the Datong River Basin at the southern foot of the Qilian Mountains as the study area, based on 119 sets of basic hydrochemical parameters and deuterium-oxygen isotope data, using multivariate statistical analysis and isotopic techniques, the hydrochemical characteristics of surface water and groundwater in the basin and their mutual transformation process were studied. The results showed that the surface water was HCO3-Mg·Ca type, which was mainly controlled by rock weathering, whereas the groundwater was HCO3-Mg·Ca type and Cl·SO4-Na type, which was controlled by rock weathering and evaporation concentration. There was a small amount of calcium and magnesium feldspar dissolved in the upstream groundwater, and the chemical components of the midstream groundwater were mainly the weathering and dissolution of carbonate rocks. The contribution rates of weathering filtration, anthropogenic activities, native sedimentary environment, alternating adsorption of cations, and other factors to the chemical components of surface water and groundwater in the study area were 39.1%, 15.0%, 12.6%, 13.8%, and 19.5%, respectively. The deuterium and oxygen isotope contents of Datong River water showed a trend of enrichment to depletion along the groundwater flow direction. The δD and δ18O isotope test results showed that the deuterium and oxygen isotope content in the Datong River along the groundwater flow showed a trend of enrichment to depletion. The upper and middle reaches of the Datong River were mainly recharged by atmospheric precipitation, whereas the lower reaches were affected by geological structure and influenced by hydrogeological conditions, which was mainly due to diving and spring water overflow to supply river water, as the discharge area of groundwater. |
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