Characteristics Of Hydrochemistry And Isotopes Of Different Water Bodies In Xilin River Basin

The Xilin River is a typical grasslas:nd basin in the Inner Mongolia Plateau.The impact of changing the environment is more profound,an-d there are environmental problems such as river channel cutoff,groun-dwater level decline,and grassland desertification.In this thesis,water chemistry and hydrogen and oxygen isotope techniques were used to stu-dy the hydrochemical and hydrogen and oxygen isotopic characteristics of precipitation,surface water and groundwater in the Xilin River Basin.The relationship between different water bodies was qualitatively analy-zed,not only for water cycle mechanism and hydrology.Model research provides theoretical support and provides basic data for studying the e-cological hydrological processes in the Xilin River Basin.The main con-elusions of this paper are as follows:1.The rivers in the Xilin River Basin are mainly weakly alkaline.The main cations in the mainstream of the river are Na+ and Ca2+,and the anions are mainly HCO3-.The Na+ in the river water comes from the dissolution,ion exchange and evaporation of rock salt;the sources of Ca2+ and Mg2+ mainly consist of dissolution of carbonate minerals and sulfate minerals,which are different in different river sections;HCO3-comes from the dissolution of carbonates.2.The characteristics of hydrogen and oxygen stable isotopes in di fferent water bodies were analyzed.The results show that the ?180 and 8D values of precipitation vary greatly and the relationship between 8180 and ?D is ?D=8.01?180+5.10‰,R2=0.98;the ?180 and ?D of the mainstream water in the river are depleted compared to the tributary,fo r the same The hydrogen and oxygen isotopes at different intervals in t he river,the characteristics of the main stream 8180 and ?D are first d epleted from depletion to enrichment,and the tributaries 8180 and 8D are enriched after de-concentration and.in the groundwater,loose rock p ores.Water and double-layer structure groundwater are shallow due to water level burial,and are affected by evaporation factors.The isotope values are more abundant.The isotope values of basalt pore fracture-loo se rock pore water and bedrock fissure water are depleted.At different time intervals,the isotopic values of various types of groundwater were enriched in July in depletion in July.After that,the isotopic values of pore water and groundwater in loose rock were gradually depleted,and the isotopic values of other types of groundwater were first depleted a nd enriched.3.Qualitative analysis of the transformation relationship between di fferent water bodies.The analysis results show that the main source of recharge of surface water and groundwater is atmospheric precipitation,which undergoes a certain intensity of evaporation and concentration wh ile replenishing.The loose rock groundwater is similar to the ?D and ?180 characteristics of the river water,and the hydraulic relationship bet ween the two is similar.The basalt pore fissure-:loose rock pore water,bedrock fissure water and double-layer structure groundwater are mixed layer water due to water at each point.As a result,the measured hydro gen and oxygen isotope content is somewhat different.