Dating of old groundwater using uranium isotopes - principles and applications. Chapter 7

This chapter provides background on the behaviour of uranium isotopes in groundwater and shows that uranium isotope disequilibrium presents a method that has the potential to play an important role within the concerted application of techniques to date old groundwater. Depending on the geochemistry of the aquifer system, the potential dating range extends from about 10 ka up to 1 M a, which overlaps the 14C and the 36Cl/81Kr dating ranges. Uranium isotopes can provide independent information relevant to groundwater age that complements other dating approaches and may help resolve ambiguities in data interpretation. Moreover, uranium isotopes in groundwater have the potential for quantifying geochemical parameters of the water–rock interaction and represent natural analogues for radioactive waste. Any multitracer application to date old groundwater should integrate uranium isotope measurements, which can easily be afforded by the use of modern mass spectrometric techniques.