河南嵩县北部基岩山区地下水水化学特征和环境同位素特征分析

An Analysis of Hydrochemical Characteristics and Environmental Isotopic Characteristics of the Groundwater in the Bedrock Mountain Area in Northern Songxian County, Henan Province

嵩县北部基岩山区位于熊耳山脉东段南部,地下水与地表水分布不均,为研究基岩山区地下水特征和补径排关系,指导缺水山区地下水找水工作,通过现场调查、地下水采样,测定不同水体中的水化学成分及环境同位素,分析其变化特征,判明地下水的补给来源及各含水层的相互联系。水化学和环境同位素研究结果表明,大气降水是研究区地下水的主要补给来源,人工开采是其主要的排泄方式;研究区基岩地下水化学特征较复杂,松散岩类孔隙水、浅(深)层半固结层裂隙孔隙水地下水以Ca^(2+)和HCO_3~–为主,属HCO_3-Ca型水;松散岩类孔隙水、浅层半固结层裂隙孔隙水含水层之间的水力联系较为密切,基岩裂隙水通过发育的导水构造断裂与现代水连接,均具有较好的开发利用价值,而深层半固结层裂隙孔隙水参与水循环的能力较弱,开采应持慎重态度。该研究成果为缺水山区地下水的合理开采利用提供了科学依据和数据支持。

The bedrock mountain area in the north of Songxian County is located in the south of eastern Xiong'er Mountain,with an uneven distribution of groundwater and surface water.With an aim to help water exploration for this region which lacks water supply,the authors conducted a study of groundwater characteristics and hydraulic relationships between recharge,runoff and discharge in the bedrock mountain area through field investigation and groundwater sampling.Hydrochemical and environmental isotopic compositions in different waters were determined from the results of water analysis of these samples.Temporal-spatial variations in these compositions indicate the recharge sources of the groundwater in this area and the interactions between the identified aquifers.The analysis of hydrochemical and environmental isotopes indicates that the primary recharge of the groundwater in this area is from precipitation,and the primary discharge results from human withdrawal.It is found that the bedrock fissure water can be classified into several types based on hydrochemistry;however,the loose rock pore water and the fissure-pore water in shallow or deep semi-consolidated strata mainly exist in Ca-HCO3waters.It is also detected that the hydraulic connection between the loose rock pore water and the fissure-pore water in shallow semi-consolidated strata is strong,and the bedrock fissure water is interacted with modern water through water-conductive tectonic fractures,which is of significance in water exploitation.Nevertheless,the fissure-pore water in deep semi-consolidated strata participates weakly in the water cycle,which should be cautious in pumping.These findings could provide scientific basis and data for sustainable utilization of the groundwater in this water-lacking area.