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The Thermodynamics of Diffusion Controlled Metamorphic Processes

  • George W. Fisher
Part of the Materials Science Research book series (MSR, volume 9)

Abstract

Many metamorphic processes involve diffusive exchange of material between interacting mineral assemblages, and in most such processes, diffusion appears to be the rate-determining step. The overall stoichiometry of diffusion-controlled processes involving p phases containing c components depends upon c — 1 ratios of diffusive fluxes. In the steady state, the flux ratios are constrained by p — 1 restrictions on the potential gradients driving the diffusion, and by c — p restrictions on the fluxes, which can be derived either from the fact that steady-state diffusion corresponds to a minimum rate of irreversible entropy production, or from the stoichiometry of the participating phases. The c — 1 flux ratios are therefore entirely determined, and can be calculated if the composition of the minerals and the ratios of phenomenological coefficients are known. Determination of the applicable diffusion coefficients is a vitally important problem.

Keywords

Mineral Assemblage Potential Gradient Flux Ratio Invariant Point Boundary Network 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

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    D.M. Carmichael, “On the mechanism of prograde metamorphic reactions in quartz-bearing pelitic rocks”, Gontr. Mineralogy and Petrology 20, 244–267 (1969).CrossRefGoogle Scholar
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    G.W. Fisher, “The application of ionic equilibria to metamorphic differentiation: an example”, Contr. Mineralogy and Petrology 29, 91–103 (1970).CrossRefGoogle Scholar
  3. 3.
    G.W. Fisher and D. Elliott, “Criteria for quasi-steady diffusion and local equilibrium in metamorphism”, in Proc. of the Carnegie Inst, of Washington Conference on Geochemical Transport and Kinetics, A.W. Hofmann and others, eds., in press.Google Scholar
  4. 4.
    G.W. Fisher, “Nonequilibrium thermodynamics as a model for diffusion-controlled metamorphic processes”, Am. Jour. Sci. 273, 897–924 (1973).CrossRefGoogle Scholar
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    S.R. de Groot and P. Mazur, “Nonequilibrium Thezmodynamics”, North Holland Publishing Go., Amsterdam, 510 (1962).Google Scholar

Copyright information

© Plenum Press, New York 1975

Authors and Affiliations

  • George W. Fisher
    • 1
  1. 1.Department of Earth and Planetary SciencesJohn Hopkins UniversityBaltimoreUSA

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