利用稳定同位素方法识别内蒙古佘太盆地地下水补给来源

Using Stable Isotope Method to Identify Sources of Groundwater Recharge in Shetai Basin, Inner Monglia

为研究近几十年来佘太盆地地下水补给变化情况,通过现场调查分析,对佘太盆地浅层地下水开展同位素样品采集工作,并测定了其氢、氧稳定同位素的值。在分析同位素分布特征及变化规律的基础上,结合当地地质及水文地质条件识别了地下水补给来源和补给区并构建了浅层地下水的补给模式图,探讨了区域上浅层地下水的补给流动状况。通过分析研究区大气降水和地下水中的氢氧稳定同位素的变化特征发现:当地大气降水并不是地下水的主要补给来源,其补给源区为周边山区,补给来源主要是周边山区的大气降水,且地下水所经历的蒸发作用较明显;盆地的东、西部地下水的补给源区不尽相同,西部的补给区高程要高于东部的补给区高程,但两部分地下水所经历的蒸发强度基本相同。

In order to study groundwater recharge in the Shetai Basin, groundwater in shallow aquifers was investigated and sampled to analyze their environmental isotope vaules. The sources of groundwater recharge can be identified by these results and regional geological and hydrogeological conditions in this paper, and the conceptual model was inferred which indicates the regional groundwater recharge conditions. The results show that the main recharge sources of groundwater in this area is not from local precipitation but from precipitation in the surrounding mountain areas and the evaporation effect of groundwater is obvious. The recharge area of the eastern part is different from the western part in this basin, and the recharge elevation of the western part is higher than the eastern part. The evaporation effect of groundwater in the two parts is similar.