The Feasibility of USD Method in Tracking Past Hydrogeochemical Changes in the Fennoscandian Shield

摘要

Uranium-series disequilibrium (USD) method is the only paleohydrogeological method that for the time scale relevant for performance assessments can detect and directly date past hydrogeochemical changes. Such changes cause U mobility which is seen as uranium-series disequilibrium. We have reviewed the method taking into account experimental and interpretation aspects and identified pros seem to outweigh identified cons. Reported USD studies in Finland and Sweden have earlier been mostly qualitative but a quantitative methodology has been developed for future studies.