乌鲁木齐河流域西山地区地下水化学特征

乌鲁木齐河西山地区位于流域中游上段山间盆地的西部,具有独特的水文地质条件,作为乌鲁木齐市的备用水源地,其地下水环境和补给排泄条件的研究非常重要。通过地表水和地下水的化学成分演化研究,结合氢氧稳定同位素分析,将地下水的补给分为两期,即全新世补给和晚更新世补给,并以此得出乌鲁木齐河在晚更新世发育于研究区现在河道的西侧,自末次冰期后由西向东摆动的结论。另外西山地区农场的灌溉活动,促进了河水的蒸发以及后续的溶解交替发生,方解石和石膏矿物不断从河水中溶解,芒硝的相对浓度不断在地下水中累积。当原河水蒸发成固相蒸发盐,然后溶解在新补给的水体中时,原河水的氢氧同位素值不再被保留下来。

Chemical Characteristics of Groundwater in Xishan Area, Urumuqi River, China

Research on recharge and discharge is important for the alternate water source in Xishan area, Urumuqi River, China. Based on analysis of the revolution of hydro-chemistry and stable isotopic of the groundwater and surface, discharge in Xishan is divided two periods, which are the Holocene and the Late-Pleistocene. Therefore, migration of the Ulumuqi River channel is revealed. The channel was located in the west of present location in the Late-Pleistocene, and changed to east after last glacial epoch. The irrigation in Xishan farm promoted the alternate action between evaporation and dissolution. Calcite and gypsum mineral were continuously eliminated from the river, and relative concentration of glauberite in the groundwater was accumulated constantly. When the original water was evaporated and formed solid phase salts, those salts were dissolved in new discharged groundwater, then hydrogen and oxygen isotopic values of the original river water no longer be preserved.