Publication Details |
| Category | Text Publication |
| Reference Category | Journals |
| DOI | 10.1016/j.jhydrol.2026.135452 |
Licence  |
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| Title (Primary) | From water-rock interactions to flow rates: insights from 234U/238U activity ratios and REE patterns of the ancient Kurnub Group Aquifer |
| Author | Nuriel, P.; Ish-Shalom, D.; Ram, R.; Siebert, C.
; Lazar, B.; Halicz, L.; Burg, A. |
| Source Titel | Journal of Hydrology |
| Year | 2026 |
| Department | CATHYD |
| Volume | 673 |
| Page From | art. 135452 |
| Language | englisch |
| Topic | T5 Future Landscapes |
| Supplements | Supplement 1 |
| Keywords | REE; 234U/238U activity ratios; Kurnub aquifer; Groundwater dating; Groundwater flow velocity |
| Abstract | Measurements of uranium isotopes and Rare Earth Element (REE) compositions were used to evaluate water–rock interaction processes, mixing, and flow rates in the Kurnub Group Aquifer (KGA), a deep confined regional sandstone aquifer extending from the Sinai Peninsula (Egypt) to the Negev Desert (Israel). The study involved developing a methodology that allowed to separate both U and REE from the brackish groundwater using a single column. Groundwater was sampled along two main flow paths of the KGA: East (n = 9) and North (n = 8), and from the overlying Judea Group Aquifer (JGA; n = 2). Overall, samples along the two KGA flow paths show consistent low REE concentrations (ppt levels) and patterns, with low LREE and HREE and high MREE. A systematic decrease in 234U/238U Activity Ratio (AR) downflow is observed along two main trend lines, from 8.37 upstream to 1.41 (non-linear) and to 3.72 (linear), with remarkable correlation to the distance from the Dead Sea outlets (R2 = 0.98). These trends suggest that uranium tracer is controlled by processes during the travel time downflow with potential relation to residence time and flow rates. Assuming minimal water–rock interactions downflow and a decrease in AR solely due to radioactive decay, long-term average flow rate of 0.29 m·yr−1 is assessed, similar to recently obtained 81Kr-based age estimates. The exceptionally high AR is observed near a major fault zone, suggesting that the highly enriched 234U may originate from this deep-seated active deformation zone, whereby fluid interactions with fractured rocks lead to the preferential leaching of the 234U isotope. |
| Nuriel, P., Ish-Shalom, D., Ram, R., Siebert, C., Lazar, B., Halicz, L., Burg, A. (2026): From water-rock interactions to flow rates: insights from 234U/238U activity ratios and REE patterns of the ancient Kurnub Group Aquifer J. Hydrol. 673 , art. 135452 10.1016/j.jhydrol.2026.135452 |
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