金塔盆地地下水演化及地球化学模拟  

Geochemical evolution of groundwater and hydrogeochemical modeling in Jinta Basin

作　　者：张清寰[1] 张彧瑞[1] 赵艳萍[1] 马金珠[1] 

机构地区：[1]兰州大学西部环境教育部重点实验室西部环境与气候变化研究院,甘肃兰州730000

出　　处：《干旱区地理》2011年第5期772-778,共7页Arid Land Geography

基　　金：科技部"973"项目(2009CB421306);国家自然科学基金项目(40872161)资助

摘　　要：以水化学和地球化学模拟技术相结合,研究了金塔盆地地下水化学演化规律。结果表明,金塔盆地地下水矿化度(TDS)由最南端的398 mg/l过渡到东北部5 280 mg/l。盆地深层地下水由南部的SO24--HCO3--Mg2+型过渡到北部的SO24--Mg2+型,浅层地下水北部为SO24+-Na+型。地下水在理化特征上来看,适宜农业灌溉。从西南到东北,地下水总体上发生了文石、方解石及白云石的沉淀,硬石膏、石膏和岩盐的溶解。偏高的Na+和Ca2+说明钙的来源较为复杂,除了淋滤作用外还有阳离子交换作用。同时Ca2+与白云岩中的HCO3-发生阳离子交换,引起HCO3-增加。Jinta basin is located on the low reaches of Beida River in the northwest of China,which is a typical oasis basin.Water resources are crucial support for regional industry,agriculture,livestock production and people's daily lives in this region.However,they have been negatively influenced by human activities for a long time.The past researches were focused mostly on the collection of basic information,little modern technologies that could search deeply about water quality and the recharge mechanism of groundwater were used.Through combining hydrochemical method and geochemical modeling,this article studied the water-rock reaction of groundwater in Jinta basin,in order to Sustainable exploitation of groundwater.The study shows that the hydrochemical types of surface water in this area aren't obvious,which are predominantly bicarbonate and sulfate.The hydrochemical types of deep groundwater in Jinta Basin varied from SO2-4-HCO-3-HCO-3 in the south to SO2-4-HCO-3 in the north.The total dissolved solid isnot very high,lower than 1 500 mg/L.It increases from 398 mg/L in the south to 5 280 mg/L in the northwest.The salt content has the same trend of variation with the total dissolved solid.The main chemical process of groundwater in Jinta basin is evaporation,and the main recharge resource is leakage water from canal flowing and irrigation.PHREEQC is a hydrogeochemical model that can be applied to calculate the saturation index of groundwater,simulate the interaction of various elements in it,and even predict the possible flowing path of groundwater.It has been widely used for studying water-rock reactions recent years.The simulated results show that there generally occur the precipitation of aragonite,calcite and dolomite,and the dissolution of anhydrite,gypsum and halite in groundwater from southwest to northeast in Jinta Basin.A high content of mNa+ and Ca2+ shows that calcium has a more complex resource,which may not only come from dissolution and infiltration reaction,but also come from cation exchange.The value o

关 键 词：地下水 水化学 模拟 金塔盆地 

分 类 号：P641.3[天文地球—地质矿产勘探]