北京昌平地区地下水地球化学
Groundwater geochemistry in the Changping area,Beijing
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摘要: 利用在北京昌平地区采集的地下水样品的同位素和水化学特征,对昌平地区的地下水补给特征进行了分析。通过对样品的分组和讨论认为:第三组样品为当地大气降水垂向入渗水体的特征;第一组样品为下覆基岩向上覆第四系含水层的顶托补给,这股基岩水可能出自碳酸盐岩含水层;第二组样品存在几种可能的补给特征;第四组样品中3件为大气降水垂直入渗补给,另1件为混合样品。研究表明,昌平地区第四系含水层地下水分布及其补给方式情况各异,实际上说明了半干旱地区山前倾斜平原地区地下水分布的复杂性。Abstract: Based on stable isotopes and chemical compositions of groundwater samples collected in the Changping District of Beijing,the characteristics of groundwater recharge are analyzed.Through the discussion of groups of the samples,it is recognized that the third group of the samples are characterized by the vertical movement to the groundwater from the infiltration of precipitation;the first group of the samples are characterized by the recharge from the underlying Carbonate aquifer bedrock to the overlying Quaternary aquifer.The second group of the samples shows the local vertical infiltration.Three samples in the 4 samples of the fourth group indicate recharge from precipitation and the other one from a mixture of recharge.The results indicate that distribution of groundwater in the Quaternary aquifer in Changping and its recharge vary greatly,showing the complexity of the groundwater distribution in the slope plain of a mountain front in a semiarid area.