【作者】 窦妍；

【导师】 钱会； 侯光才；

【作者基本信息】 长安大学 ， 地下水科学与工程， 2010， 博士

【摘要】 鄂尔多斯盆地北部的鄂尔多斯能源基地是我国能源基地建设的重点布局区域。目前鄂尔多斯能源基地建设已初具雏形,随着能源基地建设规模扩大,由于当地地表水资源的匮乏,使得对地下水资源开发的需求日益迫切。因此,如何有效、合理的开发利用地下水突显为能源基地地下水资源开发利用中最为关键的问题。本文在系统分析鄂尔多斯盆地北部的气象、水文、地质以及水文地质条件的基础上,对地下水水化学成分及环境同位素演化特征进行研究,从水文地球化学角度揭示鄂尔多斯盆地北部白垩系地下水的成因机制、赋存方式、水文地球化学演化及循环规律,并为鄂尔多斯能源基地的地下水开采提供合理建议,不仅在水文地球化学研究方面具有深刻的理论意义,而且对于鄂尔多斯能源基地的建设具有重要的实际价值。鄂尔多斯盆地北部属典型的温带大陆性气候,降水量少而集中,蒸发强烈,大风日数较多。研究区内的含水层系统主要由第四系含水岩系和白垩系含水岩系构成,根据含水层系统属性及其特征,在垂向上将研究区含水层划分为萨拉乌苏、浅层、中层和深层含水层。区内地下水流场受地形高程控制,地表分水岭与地下水分水岭基本一致,在安边-四十里梁-鄂托克梁、新召等区域性地表分水岭控制下,研究区地下水系统被分割成东部乌兰木伦河-无定河、北部摩林河-盐海子、西部都思兔河-北大池三个地下水系统。本文对研究区内地下水水文地球化学演化规律的研究主要针对四个含水层以及三个地下水系统展开。研究区水化学空间分布规律的研究以及聚类分析的研究结果表明：在萨拉乌苏组地下水以及安边-四十里梁-鄂托克梁分水岭以东的乌兰木伦河-无定河地下水系统中,地下水的矿化度大部分在1g/L以内,水化学类型主要以HCO3型水为主；在该分水岭以西的两个地下水系统——北部摩林河-盐海子、西部都思兔河-北大池地下水系统,地下水的矿化度沿着分水岭向西南、西北方向增大,矿化度最高达到5g/L以上,沿着矿化度增大方向,地下水由HCO3型水过渡为HCO3·Cl型水、HCO3·SO4·Cl型水、SO4·Cl型水和Cl·SO4型水。地下水中同位素为水文地球化学演化规律的研究提供了较好的证据,通过对研究区内地下水中δ18O、δD、14C、δ34S及Sr同位素的研究表明,研究区内不同深度的地下水主要接受大气降水的补给,并且受到了一定的蒸发作用的影响。中层和深层地下水年龄在空间上总体表现为随着地下水埋藏深度增大逐渐变老的变化特点,并且安边-四十里梁-鄂托克梁分水岭西侧地下水年龄明显老于东侧。乌兰木伦河-无定河地下水系统中的地下水由于流动速度较快,矿物溶解沉淀作用较弱,而摩林河-盐海子以及都思兔河-北大池两个含水系统中,随着深度的增加,地下水对矿物的溶滤作用增强。研究区典型剖面的水文地球化学研究是针对研究区范围较广的问题提出的,其优点在于从局部的剖面研究进一步发现整个区内在不同含水系统、不同含水层水文地球化学演化规律。研究结果表明,剖面上的水化学演化特征与前面整体的研究规律基本一致,在两个剖面上,地下水亦受到安边-四十里梁-鄂托克梁地表分水岭的控制,地下水的水化学特征以及同位素分布特征在分水岭的东西两侧呈现的规律明显不同,在分水岭的西侧,地下水呈现明显的分带性,浅、中、深层地下水的矿化度(TDS)、水化学类型以及同位素特征都不相同,而在分水岭的东侧,地下水的分带性不明显,各种水化学特征、同位素特征比较相似。通过反向水文地球化学模拟,在安边-四十里梁-鄂托克梁分水岭东西两侧,由于水岩作用明显的不同,在分水岭以西,矿物溶解进入水中,在分水岭以东,主要以矿物的沉淀作用为主。通过对研究区水文地球化学演化规律的研究对鄂尔多斯市白垩系地下水的循环规律进行了验证,结果表明,地下水动力场与水化学场所得出的地下水循环规律基本一致。区内地下水主要接受大气降水的补给,地下水在径流过程中,浅、中、深三个含水层都受到了安边-四十里梁-鄂托克梁以及新召地表分水岭的影响,其中,在安边-四十里梁-鄂托克梁分水岭以西的两个地下水系统中,地下水在安边-四十里梁-鄂托克梁和新召分水岭附近接受补给,摩林河-盐海子地下水系统中,研究区西北部的摩林河以及盐海子地区为地下水的排泄区,都思兔河-北大池地下水系统中,地下水流向西南部都思兔河下游以及北大池闭流区；在安边-四十里梁-鄂托克梁分水岭以东,水化学场的演化规律表明,浅、中、深层地下水的水力联系较为紧密,地下水更新速度较快,地下水沿分水岭向东南方向流动。在研究区内,河流,湖淖都是地下水的排泄方式。最后,根据研究区内的水文地质条件、水文地球化学演化以及地下水循环规律的研究结果,给出研究区地下水开采的规划方案,将萨拉乌苏组含水层,浅、中层含水层作为主要的开采层位,其中,萨拉乌苏组规划了8个水源地,浅、中层含水层规划了28个水源地,深层含水层作为备用的开采层位,规划了4个备用水源地,为能源基地将来的发展提供有力的科学依据。更多还原

【Abstract】 The Ordos Energy Base that distribute in the north of the Ordos Basin is the key area of construction of China’s Energy Base. The current construction of Ordos Energy Base is beginning to take shape. However, the demand of ground water resources development has become more and more urgent as the lack of local surface water resources for expanding scale of the Energy Base. Therefore, the effective and rational exploitation of groundwater have become the most critical issue for the groundwater resources development and utilization of the Energy Base. Through the study of the chemical constituents exist in groundwater and the characteristics of the evolution of the environmental isotopes, which base on the system analysis of meteorological, hydrological, geological and hydrogeologic conditions in the northern part of the Ordos Basin, to reveal the genetic mechanism, occurrence form, hydrogeochemical evolution and recycling characteristics of the Cretaceous groundwater from the hydregeochemical point of view. The study not only has profound theoretical significance, but also has important practical value for the construction of the Ordos Energy Base.The northern Ordos Basin is a typical temperate continental climate with low but concentrated precipitation, intense evaporation and a few more days wind. The aquifer system in the study area is constituted by the Quaternary water-bearing rock series and Cretaceous water-bearing rock series, and it can be divided into Salawusu, shallow, intermediate and deep aquifers in the vertical according to the aquifer system attributes and characteristics. Groundwater flow in the study area is controlled by the terrain elevation, and surface and groundwater watershed is almost consistent. Under the control of the regional surface watershed in Anbian-Sishililiang-Etuokeliang, Xinzhao and so on, three different patterns of groundwater flow systems in the study area are identified, including Wulanmulun river-Wuding river in the east, Molin river-Yanhaizi in the north and Situ river-Beidachi in the west. The study of groundwater hydyogeochemical evolution characteristics in the study area in this paper mainly focuses on four aquifer systems and three run-off areas.The study of hydrochemical spatial distribution characteristics and cluster analysis results in the study area show that most of the total mineralization degree of groundwater in the Salawusu groundwater system and Wulanmulun river-Wuding river groundwater system that lies to the east of the Anbian-Sishililiang-Etuokeliang watershed is less than 1g/L, and the chemical type of groundwater mainly is HCO3 type. The groundwater in groundwater system of Molin river-Yanhaizi in the north and Situ river-Beidachi in the west which lies to the west of the watershed mentioned above, whose total mineralization degree increase up to 5g/L or more along the watershed to the southwest and northwest, and the chemical type transit from HCO3 type to HCO3·Cl type, HCO3·SO4·Cl type, SO4·Cl type and Cl·SO4 type.The isotopes exist in groundwater provides good evidence for the hydrogeochemical evolution. Through the study of the isotopes ofδ18O,δD,14C,δ34S and Sr in the groundwater have shown that groundwater of different depth in the study area mainly recharge from the precipitation, and effect by evaporation to some extent. The overall spatial performance of middle and deep groundwater age have illustrated that the age of groundwater become older and older with the gradually increasing depth of groundwater, and groundwater age that to the west of the Anbian-Sishililiang-Etuokeliang watershed is apparent older than that to the east. The mineral dissolution and precipitation intensity is weak in the Wulanmulun river-Wuding river system as the high velocity of the groundwater flow, however, the lixiviation enhance with the depth increasing in Molin river-Yanhaizi aquifer system and Situ river-Beidachi Aquifer system.Hydrogeochemical research of the typical profile in the study area is proposed for the wider study area of the issue, and the performance of its advantage in further found different aquifer systems and different hydrogeochemical evolution characteristics. The results have shown that the hydrochemical characteristics of the profile are consistent with the overall research characteristics that mentioned above. Groundwater are subjected to the surface watershed of Anbian-Sishililiang-Etuokeliang in the two sections, and its characteristics of the hydrochemical and isotopes distribution are obvious different in the both sides of the watershed. To the west of the watershed, groundwater show clear zonation as the different of the total mineralization degree of the shallow, middle, deep groundwater, hydrochemical type and isotopes characteristics, while to the east of the watershed, the zonation of the groundwater is not obvious as the similar of the hydrochemical and isotopes characteristics. Through the reverse hydrogeochemical modeling, to the east and west sides of the Anbian-Sishililiang-Etuokeliang watershed, because of the different intensity of water-rock interaction, to the west of the watershed, the mineral mainly dissolve into the water, while mineral mainly precipitation from the groundwater to the east of the watershed.Through research the hydrogeochemical evolution of groundwater in study area in order to validate the groundwater cycle rule in the Ordos Cretaceous aquifer and the validated results show that the groundwater cycle rule derived from the hydrodynamic field is consistent with the rule from the water chemical field, reaching unity between the hydrodynamic field and the water chemical field. Precipitation is the main supply source reached to the aquifer in this area. In the runoff process, groundwater in the shallow, middle and deep aquifers have all been affected by the surface watersheds which are named as Anbian-Sishili girder-Otogs girder watershed and Xinzhao watershed. In the two groundwater systems in the west of Anbian-Sishili girder-Otogs girder watershed, groundwater accepts recharge around the watershed. In the Molin river-Yanhaizi groundwater system, however, the groundwater is discharged from the northwest of Molin river and Yanhaizi. And, in the groundwater system called Dousitu river-Beidachi, groundwater flows into the downstream of Dousitu river and Beidachi Inner flow area, both of which are in the southwest of this groundwater system. Based on the rule of water chemistry which has been researched, the hydraulic connection among the shallow, middle and deep aquifers is comparatively close and the update rate of groundwater is relatively quick and groundwater flow towards the southeast along the watershed in the east of Anbian-Sishili girder-Otogs girder watershed. Evaporation of groundwater, rivers, lakes and mud are all the ways of groundwater discharge in our study area.Finally, groundwater exploitation and planning projects are given according to the research results of hydrogeologic conditions, hydrogeochemical evolution and groundwater circulation characteristics. Salawusu aquifer, shallow and middle aquifers serve as the major exploitation aquifers, there are 8 water sources in Salawusu aquifer,24 water sources in shallow and middle aquifer, while the deep aquifer serves as the deposit exploitation aquifer. Meanwhile, the area that located in the vicinity of Anbian-Sishililiang-Etuokeliang and Xinzhao watershed, where the aquifer always have a large quantities of groundwater with good quality, and is the ideal area for construction of the water source.更多还原