Groundwater Dating and Residence-time Measurements

Geochemical constituents are transported by the circulation of the Earth's three major near-surface dynamic systems: the oceans, the atmosphere, and continental water. This chapter deals with the third of these, specifically with subsurface water. Surface water is an important medium for transporting geochemical constituents on a global scale, and is relatively easily accessed and quantified. In contrast, subsurface water is not easy to access, and fluxes through subsurface systems are very difficult to measure. This chapter explores the geochemical means that are available to help quantify subsurface fluxes, and evaluates the implications of their application to a variety of specific systems.