Imam Noha
National Institute of Oceanography and Fisheries, 101 Kaser El Aini Street, Cairo, 11516, Egypt.
Sci Rep. 2023 Jul 31;13(1):12406. doi: 10.1038/s41598-023-39333-w.
Data on the recent migratory history of radionuclides as well as geochemical circumstances can be obtained from the disequilibrium of the uranium series, which is often brought on by groundwater flow and host rock. Groundwater from the Siwa Oasis is a vital source of water for many uses, and it is distributed widely throughout the Western Desert. Groundwater in Siwa Oasis was dated using measurements of uranium in the water. In water samples that exhibited disequilibrium behavior, the activity concentrations of radionuclides from the U, U and Th series were measured. Therefore we conclude that the measured waters are rich in the U and Th. The secular equilibrium between U and Th indicates that colloidal transport could be the mechanism for the mobility of Th in groundwater. Higher Th levels in the samples show that the aquifer is deep and may have a large amount of thorium-bearing minerals. The lake and groundwater estimated ages showed that the time of uranium migration happened between 60 and 130 ka ago. This aquifer is rich in mineral deposits, as evidenced by the extraordinarily high content of radionuclides. The Th/Th activity ratio of the samples, indicating pure carbonate minerals, ranged from 12.58 to 20.86.
关于放射性核素近期迁移历史以及地球化学环境的数据可以从铀系不平衡中获得，这种不平衡通常由地下水流和围岩引起。锡瓦绿洲的地下水是多种用途的重要水源，广泛分布于西部沙漠。通过测量水中的铀对锡瓦绿洲的地下水进行了年代测定。在表现出不平衡行为的水样中，测量了U、U和Th系列放射性核素的活度浓度。因此我们得出结论，所测水体富含U和Th。U和Th之间的长期平衡表明，胶体运移可能是Th在地下水中迁移的机制。样品中较高的Th含量表明含水层较深，可能含有大量含钍矿物。湖泊和地下水的估计年龄表明，铀迁移发生在6万至13万年前。该含水层富含矿床，放射性核素含量异常高就是证明。样品的Th/Th活度比表明为纯碳酸盐矿物，范围在12.58至20.86之间。
