Author(s): M. G. Ferrick; D. J. Calkins; N. M. Perron; C. Kendall
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Abstract: In this paper the relationships between the stable isotopic signatures of river- and lake-ice cores and corresponding ice formation processes are sought. A parameter that must be determined to establish these relationships is the variable isotopic fractionation during ice growth. Ice cores obtained near the times of maximum thickness from a river impoundment and a small lake were composed predominantly of snow ice and congelation ice. Snow cover and water samples, ice thicknesses, flow velocities, and meteorological data were also obtained throughout the growth period to support the analysis. The time of initial ice cover formation differed between the two sites by about a week, and as a result the ice formation processes differed significantly. In addition, snow ice formation and highly variable met conditions led to isotopic signatures of the congelation ice that were different from others that have been reported. The diffusion model of Burton et aJ., developed to simulate solute rejection by crystals grown from the melt, was used to interpret the data. Though the model was consistent with the field data, it could not be quantitatively tested. A laboratory experiment was conducted both to support interpretations of the field data and to provide a quantitative evaluation of the diffusion model for isotope appl ications.
Year: 1998