ABSTRACT
Beyond the weathering environment, natural groundwater geochemistry evolves through a range of processes including cation exchange, dissolution of salts, and mixing with other groundwaters and brines. Soils and the shallow subsurface are environments that are typically leached of the more soluble minerals, leaving mineral alteration products, including clays and iron oxyhydroxides. Higher salinity groundwaters are typically encountered in deeper geological settings or in arid and coastal regions. Older and more slowly circulating groundwaters develop more complicated subsurface histories through rock-water interaction in these deeper settings. Unraveling the geochemical evolution of such groundwaters is important not only for water quality concerns but also for investigations of contaminant transport and assessment of such sites for waste isolation.
