摘要
This study intends to find out the evolutionary mechanism of groundwater geochemical field and groundwater cycle in the Yongding River alluvial fan of Beijing. Based on the horizontal distribution of geochemical characteristics and groundwater evolutionary process in typical profiles, the authors have reached the following conclusions:1) from the recharge area to the discharge area of Yongding River alluvial fan, different zones of groundwater chemical types can be recognized.; 2) the groundwater chemical field in different depths is affected by water-rock interaction; 3) from the recharge areas to the downstream discharge areas of the Yongding River alluvial fan, the groundwater velocity decreases gradually while the amount of dissolution/deposition for silicate, carbonate, sulfate and halite grows gradually. Therefore, the renewable velocity of groundwater decreases.