中文摘要：

马莲河流域属于水资源极端贫乏的严重缺水区域,由于河流上游的苦咸水造成整个干流水质变差使其失去了利用价值,使该流域本就十分贫乏的水资源愈加紧缺。本文在分析和研究马莲河苦咸水来源和形成机理的基础上,提出苦咸水治理的合理方案。按照时代发展的顺序,从中新元古代时期开始至晚新生代时期结束,详细研究了马莲河上游环县一带的地质、地貌的变化过程。根据地质、地貌的调查结果,结合马莲河的水质监测结果分析,对马莲河苦咸水的来源机理进行研究。将马莲河流域的水资源利用思路由＂充分利用＂变为＂保留利用＂,提出了苦咸水治理的合理方案,即在上游各个河川支流和干流的主要河段上修建像淤地坝一样的拦蓄工程,以消耗苦咸水而尽量不使其进入中下游。分析表明在马莲河上游区域修建拦蓄设施可达到以下效果：①改善气候,有利于改善流域局部小气候;②保水效益;③促进区域生态环境良性循环;④遏制流域水土流失,改善水土流失现状;⑤防洪保护效益。通过对苦咸水治理的潜在效果分析,该方案的实施具有一定的可行性。

英文摘要：

The Malian River basin is economically underdeveloped, suffering extreme water resources shortage because the upper reaches of the basin are dominated by brackish water. Examining the origin and formation mechanisms of the brackish water would be of great importance to formulate a reasonable brackish water treatment plan. The Malian River basin is located in the Ordos basin, which can be classified as the Loess Plateau landform. A detailed understanding of changes in regional geology and landscapes is needed to analyze the sources of the brackish water. The authors in the present work comprehensively examined changes in geological features of the upper reaches of the Malian River basin in chronological order from the Neoproterozoic to the late Cenozoic. We investigated the dynamics of the brackish water sources in terms of the findings associated with geology and geomorphology in combination with water quality monitoring results of the Malian River. Results show that the Huan County area, the upper reaches of the Malian River basin, was essentially the edge of the sea or in the waters of the range in the Meso-Neoproterozoic period. It may have experienced 6 times of significant sea transgression and regression in the Sinian-Early Palaeozoic period. The Huan County and Yanchi areas were the tidal flat-coastal lagoon area in the late Paleozoic-Early Mesozoic of the Early Permian Taiyuan. Dingbian, Huan Huan County, and Chenhao-Wuqi were deep lake areas from late Paleozoic to Early Mesozoic. The Malian River basin was deep lake through the mid-late Mesozoic period, and eventually became the basin center. The source of the brackish water is generally rich in sodium sulfate and sodium chloride substance due to the ever-formed sea and lakes. The brackish water flows in the form of groundwater or brings out salt in the form of spring in the spring-exposed areas in the Loess Plateau. It is suggested that the strategy of water resource utilization over the region should shift from ＂full utilization＂ to ＂reserved uti