基于惰性气体的华北平原深层地下水年代序列与古补给环境研究

大型沉积盆地含水层中赋存的地下水资源的可持续开发利用是关系区域社会经济和生态环境和谐发展的关键因素。华北平原是典型的资源型缺水沉积盆地，近几十年来的强烈开采，已引发区域地下水位持续下降、地面沉降、水质恶化等诸多环境地质问题，危机供水安全、粮食安全与重大工程安全。地下水的年龄，作为表征地下水资源可持续更新能力的重要参数，能够反映区域地下水系统流动特征以及对人类活动的响应。以往基于14C定年结果认为该区深层古地下水的年龄不超过40ka，然而近年来一些学者采用36Cl和4He等手段研究后认为深层承压水的年龄已远远超出了14C的测年上限。因此，本项研究将联合应用多种环境示踪剂（14C、4He和81Kr）定年方法，构建华北平原深层地下水的年代序列，同时结合惰性气体重建古温度与古湿度信息，以揭示区域地下水系统的流动规律与古补给环境演化，为华北平原区域经济社会可持续发展和国家重大需求提供重要科学依据。

The sustainable development and utilization of groundwater resources in large sedimentary basins is significant for the harmonious development of regional socio-economic and ecological environment. The North China Plain is a typical water-deficient region. An intensive exploitation of deep confined freshwater over the last several decades has caused many environmental and geological problems such as the continuous decline of groundwater level, land subsidence, and deterioration of water quality in the area，which also threatens the safety of water supply, food security, and major engineering safety. The age of groundwater, as an important parameter to characterize the properties and renewal ability of groundwater resources, can reflect regional groundwater system flow characteristics and response to human activities. The previous results of groundwater ages in the deep confined aquifer were not more than 40 ka by using 14C method. However, some scholars suggested that the groundwater age is far beyond the 14C dating limit by using 36Cl and 4He approaches. Therefore, this study will combined multiple environmental tracers (14C, 4He and 81Kr) to accurately determine the age of deep confined water in the North China Plain. Meanwhile, combining the dissolved noble gases to restore the paleo-temperature and paleo-humidity information, to reveal the formation and evolution process and the paleo-recharge environment of the regional groundwater system, and provide important scientific basis for the sustainable economic and social development of the North China Plain and the major national needs.