玛纳斯河流域水化学时空分异特征及成因解析OA

The periodic differentiation of chemical characteristics in surface and groundwater can reveal the ex-tent of the interaction between natural conditions and human disturbance in arid agricultural regions,thus offering insights into the dynamics of water system evolution.To investigate the spatiotemporal coupling and differentia-tion of water chemistry in the Manas River Basin,we collected 184 surface and groundwater samples in April(pre-irrigation),July(mid-irrigation),and October(post-irrigation)of 2024.We employed Piper diagrams,Gibbs diagrams,and reverse geochemical modeling to systematically analyze the spatiotemporal interactions and driv-ing factors of water chemistry across four geological units:The low-latitude mountainous area,piedmont plain ar-ea,artificial oasis area,and desert transition zone throughout the irrigation cycle.The results show that(1)Water chemistry types display a gradient spatial differentiation pattern,transitioning from the HCO3-Ca·Mg type in the low-latitude mountainous area to the Cl·SO4-Na type in the desert transition zone.Irrigation activities drive the artificial oasis and desert transition zones through three stages of salinization,evolving from the HCO3-Ca type in the pre-irrigation period to the high-salinity Cl·SO4-Na type in the post-irrigation period,following a temporal differentiation pattern.(2)In the low-latitude mountainous and piedmont plain areas,water chemistry is primarily influenced by water-rock interactions.By contrast,the artificial oasis area and desert transition zone are affected by both evaporation and crystallization processes,as well as human activities,which intensify during the mid-and post-irrigation periods.Na+,K+,and Cl-primarily originate from rock salt dissolution and cation exchange,whereas Ca2+,Mg2+,and HCO3-mainly derive from dolomite and calcite dissolution,with SO42-primarily coming from gypsum dissolution.(3)Water-rock interactions are largely driven by dolomite and calcite dissolution and cation exchange,with minimal contributions from rock salt and gypsum,exhibiting distinct temporal differentia-tion characteristics.Through a comprehensive analysis of water chemistry differentiation and its controlling fac-tors across multiple spatiotemporal scales,this study provides a scientific foundation for the sustainable manage-ment of surface and groundwater systems and for the prevention and control of salinization in arid regions.