内蒙古腰坝绿洲地下水化学特征及成因分析

Hydrochemical characteristics and causes of groundwater in Yaoba Oasis of Inner Mongolia

选取内蒙古自治区腰坝绿洲66个地下水样点的化学数据为研究对象,运用经典统计学、Piper三线图、Gibbs图、主离子浓度关系图等方法,对地下水化学特征和成因进行分析。研究结果显示,研究区地下水呈弱碱性微咸水,化学过程主要以蒸发浓缩-岩石风化作用为主,地下水化学组分以方解石、白云石、岩盐与石膏的溶解沉淀为主要来源。研究结果表明,研究区从东北向西南地下水化学类型由SO_(4)·Cl-Ca·Mg型和SO_(4)·HCO_(3)·Cl-Mg·Na型转化为SO_(4)·Cl-Ca·Na型,形成高盐分离子的富集,水体总体咸化程度明显。

Groundwater is very important water source for the survival and development of oasis in arid area.The hydrochemical data of 66 groundwater samples in Yaoba Oasis of Inner Mongolia were selected to analyze the hydrochemical characteristics and genesis of groundwater with methods of classical statistics,Piper trigraph,Gibbs graph,main ion concentration graph,etc to understand the chemical characteristics and causes of groundwater,and also to provide the basis of data for water quality evaluation.Results showed that the groundwater presented weak alkalinity and brackish water.The main chemical processes were evaporation concentration and rock weathering.The main sources of groundwater chemical components were dissolution and precipitation of calcite,dolomite,rock salt and gypsum.From northeast to southwest,the chemical types of groundwater changed from SO_(4)·Cl-Ca·Mg and SO_(4)·HCO_(3)·Cl-Mg·Na to SO_(4)·Cl-Ca·Na.The high salt ions were enriched.The overall salinization degree of the groundwater body is obvious.It will provide guidance for rational exploitation and protection of groundwater in this area.