中文摘要：

地下水化学演化特征研究对受人类干扰严重、生态系统脆弱的干旱地区地下水资源开发具有重要意义。以焉耆盆地开都河北岸灌区作为研究对象，利用该地区不同时期292组潜水水化学数据，在沉积环境分区基础上研究该地区潜水水化学的时空演化规律，探讨其原因。结果表明，研究区潜水水化学在时间和空间上存在明显的演化特征，即随着时间的推移，研究区潜水向淡化方向演化，低矿化度的HCO3与HCO3-SO3型水分布范围增加；空间上，各时期潜水水化学组分从开都河上游到下游变化程度逐渐增大。研究区水化学时空演化特征的形成与其干旱气候密不可分，但半世纪以来人类gl水灌溉、农渠排水和地下水开采是导致潜水水化学演化的主要驱动力。

英文摘要：

Study on the evolution c iaaracteristics of groundwater hydrochemistry has great significance for groundwa＇ter resources development, especially in the arid areas with fragile ecosystems and disturbed se- verely by human activities. In this paper, 292 groups of phreatic water chemistry data from different time were collected in the northern irrigation district of Kaidu River in Yanqi Basin. The spatial and temporal characteristics of hydroehemieal evolution of the phreatic water were analyzed to explore the driving force of hydrochemical evolution. The results indicated that the geochemical characteristics of the phreatic water in the study area are vary in both temporal and spatial scale. The phreatie water in the study area has been desalting gradually with time. The distribution area of groundwater with the type of HCO3 and HCOa-SO4 and with low TDS has been increasing. The concentrations of chemical compositions of the phreatic water is gradually increasing at different degree from upstream to downstream of Kaidu River. The spatial and temporal hydrochemical evolution of the phreatic water in study area is closely related to arid climate. However, irrigation, drainage and groundwater resources exploitation are the main driving forces caused hydrochemical evolution of phreatic water.