【作者】 陈立；

【导师】 张发旺； 余秋生；

【作者基本信息】 中国地质科学院 ， 地质工程， 2005， 硕士

【摘要】 宁夏南部山区是全国水资源最贫乏的地区之一，由于淡水资源的短缺，该地区经济发展缓慢，群众生活水平低下。淡水资源奇缺的原因之一是该地区广泛分布第三系地层，其中含有大量易溶盐，且地层中泥质成分含量多。本文以宁南地区西吉县为例，探讨第三系地层对当地地下水的影响作用。本文首先利用地层学和古地理学原理与方法，研究西吉县第三纪沉积环境演化过程，绘制不同时期沉积岩相图。第三纪大部分时间，西吉处于内陆湖盆状态，气候干旱，大量盐份浓缩沉积在湖底被保存下来，使得该地层中地下水水质变坏。其次，借助MapInfo、ArcView GIS和FEFLOW软件，利用以往钻孔资料，研究了第三系地层的分布范围、厚度等特征，并建立了地层空间结构模型。西吉境内，红柳沟组地层几乎遍布全境，干河沟组地层只分布在月亮山西麓；清水营组地层厚度最大，平均400m，寺口子组地层厚度最小。另外，运用地质、水文地质和水文地球化学等综合方法，研究了该地区地下水特征；运用多元统计方法，分析了第三系地下水中各指标之间、样品与指标之间的相关关系；定性的分析了第三系地层对地下水水质的影响作用。由于第三系清水营寺口子组地层中易溶盐含量高，经过淋滤，大量盐份进入地下水中，“污染”了地下水；该类地下水以补给的方式，混合到第四系砂砾石承压水中使其水质变差。最后，对开发利用当地地下水提出了建议。更多还原

【Abstract】 The southern Ningxia is one of the most deficient region of water resources, due to shortage of fresh water resources, the economic development makes slow progress in the region, the people living standard is low, the reason for fresh water resources shortage is that Tertiary geologic strata are extensively distribute on the area, and contains large quantity easily dissolve salt, and also the argillaceous ingredient content are large in the stratum. This article, with Xiji County of southern Ningxia as the example, discusses Tertiary strata’s influence on the local ground water.First of all, the paper deals with the evolution process of Tertiary sedimentary in Xiji Country and provides the sedimentary litho-phase maps of various seages. during the most time of Tertiary, Xiji was in the inland lake basin and salt deposited in the lake bottom due to the dry climate, with a result that ground water in the stratum shows high content of salt. With the application application of Mapinfo, Arcview GIS and FEFLOW, and based on the bore hole drilling data, the distribution extent and thickness of the Tertiary have been analyzed and the stratum spatial model has been established. In Xiji, the Hongliugou Formation is only distributed in whole area, while the Ganhegou Formation is only distributed in the area west of Yueliangshan mountain. The Qingshuiping Formation is the thickest, about 400m on average and the sikouzi Formation is the thinnest. Moreover, with comprehensive statistical method, the interrelation between the sample and index of groundwater in Tertiary.In addition, the effect of Tertiary strata on groundwater quality has been analysed qualitatively. Because the content of soluble salt in Tertiary water bearing formation is high, so a great amount of salt will enter groundwater and pollute groundwater. This type of groundwater recharges Quaternary confined groundwater and made water quality deteriorate. At last, the suggestion for groundwater exploitation and utilization have been put forward.更多还原