Physical Sciences and Mathematics Commons^™

Deuterium And Oxygen-18 Diffusion In A Confined Aquifer: A Numerical Model Of Stable Isotope Diffusion Across Aquitard-Aquifer Boundaries, Benjamin J. Currens

Theses and Dissertations--Earth and Environmental Sciences

The stable isotopes ²H and ¹⁸O, combined with noble gases and radioisotopes (e.g., ³H, ¹⁴C, ³⁶Cl), are used to infer groundwater age and climate during recharge. Flow regimes within low-velocity flowpaths and long residence times could allow an aquitard-aquifer diffusive flux to alter isotope abundance. Consequently, the diffusion of isotopes (e.g., ¹⁴C, ²H and ¹⁸O) between aquifers and confining layers needs to be considered in such conditions. In this study, COMSOL Multiphysics was used to determine if diffusion of ¹⁸O (and ²H by proxy) from a bounding aquitard could explain …