Study On The Evolution Of Chemical Composition Of The Water In The Jingbian Area In The Middle Of Ordos Basin

Jingbian area lies in the central part of Ordos Basin, is the important component part of China's Heavy Industry Energy Base in Yulin and the investment hot-spot areas in China's western region. This district has the characteristics of fragiled ecological environment, the . shortage of water resources, complexed water quality water environment in bad condition. Therefore, a research about in Chemical Evolution of the groundwater has been carried out. The research results provides scientific base for reasonable exploration, utilization and protect of groundwater resources, which was significant tomitigate the shortage of water resources.Based on analysis to these datas, such as the hydrological, meteorological, geological, hydrogeological, hydrochemistry, isotopic data, and the results of previous studies collected and analyzed by the author. Using the methods of Comprehensive hydrogeological analysis, the author thinks that aquifer system in this region are composed by Quaternary aquifer and Luohe and Huanhe formation in Lower Cretaceous aquifers, the system's bottom boundary is Anding formation in Jurassic, the Tertiary stratum is relative impermeable layer between Quaternary stratum and Cretaceous stratum, and the groundwater runoff system is complex flow system consists of deep and shallow regional flow system located in different layers, scope, depth.The mineralization of surface water and groundwater in these three aquifers are thought of less than 1g/L after analyzing the characteristics of hydrochemistry, are mainly bicarbonate; By analysis of isotope characteristic, the conclusions are obtained that the surface water and groundwater in this region is mainly recharged by precipitation, and suffered the action of evaporation and concentrate, there are little rain water penetrate into Cretaceous aquifer and no ancient sedimentary water.According to the theory of hydrochemistry and the results of modeled, the chemical species in groundwater and saturation indexes of minerals are obtained, and the backward geochemical model was corried on different physiognomies along the flow direction of groundwater. The results showed that: the dissolution of gypsum and desorption of Na~+ is the main effect in the three different water bearing layers, and the other minerals have different infection for the chemical composition of groundwater ,such as calcite, dolomite, halite etc.The research on distribution and evolution of chemical composition of precipitation, surface water and groundwater has been carried out comprehensively, this results has important value for interpretation of the interaction of surface water and groundwater as well as the mechanism of interaction between groundwater aquifer study. Based on above results, the development of water resources and the corresponding water environmental protection measures have been established, which are the foundation of the groundwater environment carrying capacity and rational development and use of groundwater, and research results can be used in other similarly areas too.