内蒙古河套平原现代湖泊的水化学特征及成因类型

Hydrochemical Characteritics and Genetic Types of Modern Lakes in Hetao Plain

摘要:

在1∶5万区域地质调查的基础上，于山前—黄河—沙漠沿线采集湖水、地下水样品16组，分析其水化学特征，并结合遥感解译和钻探等技术方法划分了河套平原现代湖泊的成因类型。研究表明该区湖泊多数为淡水—微咸水湖，水化学类型呈Na(Mg)(Ca)HCO3(Cl)型;少数为咸水湖，水化学类型呈Na(Mg)(K)Cl(SO4)型，湖水TDS变化较大，介于0.857~7.36g/L，主要接受引黄灌溉补给和山前地下水侧向补给。湖泊的成因类型可分为河流成因的牛轭湖、基底为全新世黄河古河道冲积砂层的风蚀湖及基底为全新世风积沙层的风蚀湖；其中以Ⅱ型占主导地位。

Abstract:

This paper classified genetic types of modern lakes in the Hetao Plain by means of remote sensing interpretation and drilling on the basis of 1∶50000 regional geological mapping.In addition, sixteen lake water and groundwater samples were taken from piedmont,desert and the Yellow River.The hydrochemical characteristics of those samples were analyzed. Results showed that ：Most of the modern lakes in Hetao Plain are fresh-brackish water lakes,which are Na-(Mg)-(Ca)-HCO3-(Cl) type.The others are saltwater lakes,which present a Na-(Mg)- (K)-Cl-(SO4) type.The TDS of lake water changes from 0.857g/l to 7.36g/l.The lakes mainly receive recharge from the piedmont groundwater and the irrigated water of the Yellow River；there are three main genetic types of lakes:Ⅰ.oxbow lake made by river,Ⅱ. wind-erosion lake on a base of ancient Yellow River alluvial sand layer,Ⅲ. wind-erosion lake on a base of Holocene aeolian sand layer,in which the typeⅡ is dominant.