铀系不平衡在大同南寒武-奥陶系地下水资源研究中的应用

在大同口泉沟南寒武-奥陶系碳酸盐岩地下水资源勘探研究中,应用了铀放射系不平衡方法.由地下水中234U与238U放射性活度比的不平衡对相邻泉域作出区别,划分出岩溶地下水的3种类型,相应于强、中、弱径流条件和不同的含水层环境.利用234U盈亏指标识别了本区各岩溶地下水子系统、相互关系、补给源和混合比及其与侧向补给和侧向排泄的关系.地下水中铀含量和活度比有较大变幅,神头泉有罕见的小于久期平衡的铀放射性活度比.

Uranium Disequilibrium in the Cambrian-Ordovician Aquifer System of Southwest Datong and Its Application for Groundwater Research

A study of uranium disequilibrium in groundwater from the Cambrian-Ordovician(∈-O)carbonate aquifer system,the Mouthspring,southwest of Datong has been undertaken to answer questions pertaining to the development of this aquifer system.An adjacent ∈-O aquifer system,the Deityhead Spring,is differentiated from the Mouthspring using activity ratio of ²³⁴U/²³⁸U,third kinds of ∈-O groundwater related to strong to weak circulation patterns and aquifer environments are interpreted,too.²³⁴U excess is used for identification of many ∈-O subsystems,their mutual relations and the lateral recharge and discharge as well. The source waters of these subsystems are deduced,contributions of these waters are evaluated quantitatively by mixing ratios.The concentration and activity ratio of uranium in ∈-O groundwater are varied greatly,it is seldom seen that activity ratios less than that of the secular equilibrium are found from ∈-O groundwater of the Deityhead-spring.