CHARACTERIZING GROUNDWATER FLOW IN GLACIATED TERRAIN USING HIGH RESOLUTION PROFILES OF STABLE ISOTOPES OF POREWATER

High-resolution (meter scale) 1-D profiles of the stable isotopes of porewater (delta deuterium and oxygen-18) were measured on core samples collected from thick, complex, glaciated systems using a direct equilibration technique. These high-resolution vertical profiles yielded valuable hydrogeologic information on groundwater flow, information that could not have been obtained using conventional methods. At one site in Saskatchewan, Canada, the isotopic profile revealed the presence of three distinct hydrogeological zones. An upper zone (5-10 m depth) controlled by a sand layers having a high K. The lack of vertical variability in porewater isotope data in an intermediate zone (10-30 m depth) suggested groundwater flow and solute transport was controlled by a system of interconnected vertical fractures and lateral sand layers. The shape of the porewater isotope profile in the lower zone (30-63m depth) suggested that solute transport was dominated by molecular diffusion.