Based on historical analysis of regional geography and geology with the confirmed evidences from environmental isotopes and succeeding change of continental salinized salt water,it is found that the groundwater flow systems in the Quaternary of Hebei Plain have undergone three major evolution stages since the Last Glacial Maximum.In the low sea level stage of 18-15 ka BP,groundwater recharge from abound rainfall almost fully replaced the original water in the Quaternary aquifers,and the regional flow system developed.In the period of sea level sharply rising stage of 15-12 ka BP,the flow driven force weakened as the result of topographic potential differences decreased; the early intermediate flow systems penetrating to the third aquifer developed and the regional flow system tended to be stagnant.From the stage of 2.5 ka BP to the present,the present fluvial morphology formed,the topographic potential differences between mountain and sea decreased continually,and the potential differences between high river beds and low river beds or depressions became the dominated flow driven force,so that the late intermediate flow systems penetrating to the first and second aquifers developed.Along with sea level rising,the penetrating depth of later flow systems being less than the former,thus,the later partly cut and superimposed on the former.At present,it is a temporal and spatial assemblage of groundwater flow systems of different evolution stages in the Quaternary of Hebei Plain.Such a scene might be seen in other costal basin,even in inland basin if the erosion weakened with time.The continental salinized saline water originated in around 12 ka BP,resulting in saline water and soil salinization by upward flow,is the key negative factor in water resources management and in ecology and environment protection of Hebei Plain.%以区域自然地理及地质历史分析为基础,以环境同位素及大陆盐化咸水后期变化为实证依据,重塑了末次盛冰期以来河北平原第四系地下水流模式演变.研究发现,末次盛冰期以来河北平原第四系地下水流系统经历3个演变阶段:(1)距今18～15 ka的低海平面时期,接受持续补给,地下水得到充分交替,发育穿透达到或接近第四系底界的区域水流系统；(2)距今15～12 ka的海平面急剧抬升期,地形势差减弱,发育穿透第三含水层组的早期中间水流系统,与此同时区域水流系统趋于停滞；(3)距今2.5ka以来,现代河流地貌成形,高位河床与低位河床及河间低地的势差成为主要驱动力,发育穿透第一及第二含水层组的晚期中间水流系统.随着海平面抬升,后期发育的水流系统切割前期水流系统的一部分并叠置其上.因此,现今河北平原第四系的地下水流系统乃是不同演变时期地下水流系统的时空四维集合体.其他濒海平原,乃至侵蚀强度随时间减弱的内陆盆地,都有可能出现类似图景.距今12 ka前后形成的大陆盐化咸水,由上升水流带到浅部,导致浅层咸水以及土地盐渍化,乃是河北平原水资源利用及生态与环境保护的关键性不利因素.
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