古堆泉域岩溶地下水水化学特征及成因

Hydrochemical Characteristics and Formation Causes of Ground Karst Water Systems in Gudui Spring Catchment

古堆泉为山西省著名岩溶大泉之一,是唯一的中低温温泉,具有悠久的开发观赏历史,凝聚着丰厚的人文积淀.以古堆泉域岩溶地下水为研究对象,通过系统地样品采集与同位素分析,综合运用水化学(Durov图、离子比例、 Gibbs图和氢氧同位素)同位素方法分析地下水水化学特征和地下水系统径流特征.古堆泉域岩溶地下水的^(87)Sr/^(86)Sr值在0.709~0.717之间,Mg/(Mg+Ca)值在0.27~0.74之间.通过分析Sr同位素组成和Mg/(Mg+Ca)、 1/Sr变化特征,得出古堆泉域岩溶地下水为深部热水与浅部冷水的混合水,中条山南梁泉岩溶水子系统呈现碳酸盐岩地层径流特征,佛岭山-高显海头泉岩溶水子系统和侯马盆地深循环子系统呈现碳酸盐岩地层与火成岩地层径流特征,塔儿山-九原山古堆泉岩溶水子系统呈现碳酸盐岩地层与古老硅铝质岩地层径流特征.通过2014年样品与2021年相同位置取样点的氢氧同位素比对分析,得出古堆泉口水样变化原因是其受三泉水库补给随时间的积累的结果,三泉水库的变化原因是受引黄水的影响.研究区岩溶地下水水化学类型可分为SO_(4)-Na、 SO_(4)-Ca、 HCO_(3)-Na、 HCO_(3)-Mg、 HCO_(3)-Ca和Cl-Na型.岩溶地下水水化学类型从HCO_(3)-Ca·Mg→HCO_(3)·SO_(4)-Ca·Mg→SO_(4)·HCO_(3)-Na·Ca→SO_(4)·Cl-Na·Ca呈现明显的水化学成分分带.

As one of the famous karst springs in Shanxi Province,the Gudui spring is the only medium⁃low temperature hot spring,with a long history of development and a rich cultural accumulation.The karst groundwater in the Gudui spring catchment was taken as the research object.Through systematic sample collection and isotope analysis,hydrochemistry(Durov map,ion ratio,Gibbs map,and hydrogen and oxygen isotope)methods were comprehensively used to analyze groundwater hydrochemistry and groundwater system runoff characteristics.The ^(87)Sr/^(86)Sr value of karst groundwater in the Gudui spring catchment was 0.709 to 0.717,and the Mg/(Mg+Ca)value was 0.27 to 0.74.By analyzing the Sr isotope composition and Mg/(Mg+Ca)and 1/Sr variation characteristics,it was concluded that the karst groundwater in the Gudui spring catchment was a mixture of deep hot water and shallow cold water.The karst water subsystem of Nanliang spring presented the characteristics of carbonate stratum runoff.The karst water subsystem of Fuling Mountain Gaoxian Haitou spring and the deep circulation subsystem of Houma Basin exhibited the runoff characteristics of carbonate rock and igneous rock strata.The karst water subsystem of Taiershan Jiuyuanshan Gudui spring presented the runoff characteristics of carbonate rock and ancient silicoaluminate strata.Theδ^(18)O value in karst groundwater of Guodui spring area ranged from-11.46‰to-7.81‰,and the average value was-10.08‰.The range of theδD value was-83.7‰to-60.8‰,and the average value was-73.6‰.This showed that karst groundwater in the spring area was the result of mixing of various types of water.Through comparative analysis of hydrogen and oxygen isotopes of 2014 and 2021 sampling points at the same location,it was concluded that the change in water samples at the Guduiquan resulted from the gradual accumulation of water supplied by Sanquan Reservoir.The change in Sanquan Reservoir was due to the influence of Yellow River diversion.The karst groundwater in the spring area were characterized by large calcium ion,magnesium ion,and sodium ion values;a small potassium ion value;a large sulfate value;and a small chloride value.The hydrochemical types of karst groundwater in Gudui spring catchment could be divided into SO_(4)⁃Na,SO_(4)⁃Ca,HCO_(3)⁃Na,HCO_(3)⁃Mg,HCO_(3)⁃Ca,and Cl⁃Na.The hydrochemical types of karst groundwater showed evident hydrochemical composition zoning from HCO_(3)⁃Ca·Mg→HCO_(3)·SO_(4)⁃Ca·Mg→SO_(4)·HCO_(3)⁃Na·Ca→SO_(4)·Cl⁃Na·Ca.According to the comprehensive analysis of hydrochemical isotope and hydrogeological conditions,the karst water subsystem of Nanliang spring was primarily recharged by rainfall infiltration in the exposed limestone area and river infiltration,and its karst groundwater was recharged by runoff from south to north to the karst water subsystem of Fuling Mountain Gaoxian Haitou spring and the deep circulation subsystem of Houma Basin.The karst water subsystem of Taier Jiuyuan Mountain Gudui spring received rainfall infiltration supplement and upstream runoff supplement from the exposed limestone area.Its karst groundwater flowed from north to south and received the supply of Sanquan Reservoir from Yellow River water in the natural discharge area of Gudui spring.