Numerical modeling of diffusive exchange of stable isotopes in the lithologic setting
John M. Eiler, Lukas P. Baumgartner, John W. Valley · CaltechAUTHORS (California Institute of Technology) · 1991
The emergence of micro-analytical methods of measuring stable isotopic ratios (Valley and Graham, 1991, Crowe et al., 1990, Sharp, 1990) has made it increasingly important to develop models predicting the effects of diffusive exchange of stable isotopes between coexisting phases within realistic petrologic environments. Previous models have used the concept of diffusional closure (Dodson, 1973), which assumes a rapidly diffusing infinite reservoir exchanging with a mineral of interest; an assumption which will not hold for many polyphase interdiffusion problems of petrologic interest. We have used a numerical model for interdiffusion using the Crank-Nicholson finite difference formulation, assuming rapid grain boundary diffusion and net mass balance to link the individual grains.