An overview of (super 14) C analysis in the study of groundwater.

Abstract

This paper provides a summary overview of the current state-of-art in the radiocarbon dating of groundwater. While the use of natural (super 14) C measurements in applied hydrogeology still presents a difficult challenge, meaningful dates can be achieved if they are determined and interpreted in conjunction with the analyses of other isotopic species that occur in the natural environment. Although (super 14) C dating of groundwater can be, and often is, carried out as a matter of routine, any specific case study requires its own scientific design and effort. As is widely recognized, and discussed in considerable detail throughout the scientific literature, there are many hydrogeochemical reactions and/or physical processes that can alter the natural (super 14) C enrichment measured in environmental materials. Fortunately, for fresh groundwater resources such effects are in general well defined and therefore of limited significance. The primary challenge in applied groundwater dating is with the development of the appropriate theoretical background against which (super 14) C dates can be used to calibrate numerical analogues of the groundwater system. The hydraulic properties of each of the widely used finite-element models can be well estimated from numerous piezometric data and extrapolations. In contrast, only a few groundwater ages can be provided for the calibration of those models that are complex functions of aging mixture and sometimes also hydrochemical reactions.