Diffusion in Polycrystalline Materials: Grain Boundaries, Mathematical Models, and Experimental Data

Dohmen, Ralf; Milke, Ralf

doi:10.2138/rmg.2010.72.21

Cited by 107 publications

(65 citation statements)

References 124 publications

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“…In 456 this case the diffusion coefficient, D, is a bulk diffusion coefficient, where the individual 457 diffusion properties of the multi-phase system including fast diffusion paths like interface and 458 grain boundaries are averaged in an appropriate way. Such an approach is only justified in a 459 certain time regime (Type A diffusion regime, e.g., Dohmen and Milke, 2010), in which a 460 representative volume of rock can be homogenized effectively by diffusion. As we have 461 argued before, the individual minerals of a rock specimen seem to reflect elemental and 462 isotopic equilibrium and hence this time regime has been reached at some point.…”

Section: Diffusion Of LI From Enriched-zone Into Country Rock 436mentioning

confidence: 99%

The influence of melt infiltration on the Li and Mg isotopic composition of the Horoman Peridotite Massif

Lai

Strandmann

Dohmen

et al. 2015

Geochimica et Cosmochimica Acta

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Section: Diffusion Of LI From Enriched-zone Into Country Rock 436mentioning

confidence: 99%

The influence of melt infiltration on the Li and Mg isotopic composition of the Horoman Peridotite Massif

Lai

Strandmann

Dohmen

et al. 2015

Geochimica et Cosmochimica Acta

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“…Diffusion along such intracrystalline defects is faster than bulk diffusion, as recently reviewed by Dohmen and Milke (2010). As temperature decreases, the role of high-diffusivity pathways becomes increasingly important in facilitating intragranular element mobility.…”

Section: Introductionmentioning

confidence: 99%

The legacy of crystal-plastic deformation in olivine: high-diffusivity pathways during serpentinization

Plümper

Vollmer

et al. 2011

Contrib Mineral Petrol

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Crystal-plastic olivine deformation to produce subgrain boundaries composed of edge dislocations is an inevitable consequence of asthenospheric mantle flow. Although crystal-plastic deformation and serpentinization are spatio-temporally decoupled, we identified compositional readjustments expressed on the micrometric level as a striped Fe-enriched ( " X Fe = 0.24 ± 0.02 (zones); 0.12 ± 0.02 (bulk)) or Fe-depleted ( " X Fe = 0.10 ± 0.01 (zones); 0.13 ± 0.01 (bulk)) zoning in partly serpentinized olivine grains from two upper mantle sections in Norway. Focused ion beam sample preparation combined with transmission electron microscopy (TEM) and aberrationcorrected scanning TEM, enabling atomic-level resolved electron energy-loss spectroscopic line profiling, reveals that every zone is immediately associated with a subgrain boundary. We infer that the zonings are a result of the environmental Fe 2? Mg -1 exchange potential during antigorite serpentinization of olivine and the drive toward element exchange equilibrium. This is facilitated by enhanced solid-state diffusion along subgrain boundaries in a system, which otherwise re-equilibrates via dissolutionreprecipitation. Fe enrichment or depletion is controlled by the silica activity imposed on the system by the local olivine/orthopyroxene mass ratio, temperature and the effect of magnetite stability. The Fe-Mg exchange coefficients K Atg=Ol D between both types of zoning and antigorite display coalescence toward exchange equilibrium. With both types of zoning, Mn is enriched and Ni depleted compared with the unaffected bulk composition. Nanometer-sized, heterogeneously distributed antigorite precipitates along olivine subgrain boundaries suggest that water was able to ingress along them. Crystallographic orientation relationships gained via electron backscatter diffraction between olivine grain domains and different serpentine vein generations support the hypothesis that serpentinization was initiated along olivine subgrain boundaries.

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“…These models have been substantiated by a vast body of rigorous experimental work constraining the kinetics of reaction rim growth (e.g. Farver and Yund, 1996;Yund, 1997;Fisler et al, 1997;Milke et al, 2001;Watson and Price, 2002;Milke and Heinrich, 2002;Milke and Wirth, 2003;Abart and Schmidt, 2004;Schmid et al, 2009;Götze et al, 2010;Keller et al, 2008;Niedermeier et al, 2009;Dohmen and Milke, 2010;Keller et al, 2010;Joachim et al, 2011a, b;Mueller et al, 2012;Helpa et al, 2014Helpa et al, , 2015Jonas et al, 2015;Abart et al, 2016). Phenomenological models of disequilibrium elemental and isotopic compositions produced experimentally with incomplete diffusive element exchange (e.g.…”

Section: Reaction Kineticsmentioning

confidence: 99%

“…Ongoing experimental work aimed at characterizing rate-limiting reaction mechanisms and their petrogenetic signatures in more complex, highervariance systems is imperative to allow further refinement of partial equilibration models necessary to fully understand coronas. Reviews of the experimental basis for kinetic theory, reaction mechanisms and the petrogenetic implications of this work are provided by Putnis (2009), Dohmen and Milke (2010), Mueller et al (2010Mueller et al ( , 2015, and Zhang (2010).…”

Section: Reaction Kineticsmentioning

confidence: 99%

Arrested development – a comparative analysis of multilayer corona textures in high-grade metamorphic rocks

Ogilvie

Gibson

2017

Solid Earth

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Abstract. Coronas, including symplectites, provide vital clues to the presence of arrested reaction and preservation of partial equilibrium in metamorphic and igneous rocks. Compositional zonation across such coronas is common, indicating the persistence of chemical potential gradients and incomplete equilibration. Major controls on corona mineralogy include prevailing pressure (P ), temperature (T ) and water activity (aH 2 O) during formation, reaction duration (t) single-stage or sequential corona layer growth; reactant bulk compositions (X) and the extent of metasomatic exchange with the surrounding rock; relative diffusion rates for major components; and/or contemporaneous deformation and strain. High-variance local equilibria in a corona and disequilibrium across the corona as a whole preclude the application of conventional thermobarometry when determining P -T conditions of corona formation, and zonation in phase composition across a corona should not be interpreted as a record of discrete P -T conditions during successive layer growth along the P -T path. Rather, the local equilibria between mineral pairs in corona layers more likely reflect compositional partitioning of the corona domain during steadystate growth at constant P and T .Corona formation in pelitic and mafic rocks requires relatively dry, residual bulk rock compositions. Since most melt is lost along the high-T prograde to peak segment of the P -T path, only a small fraction of melt is generally retained in the residual post-peak assemblage. Reduced melt volumes with cooling limit length scales of diffusion to the extent that diffusion-controlled corona growth occurs. On the prograde path, the low melt (or melt-absent) volumes required for diffusion-controlled corona growth are only commonly realized in mafic igneous rocks, owing to their intrinsic anhydrous bulk composition, and in dry, residual pelitic compositions that have lost melt in an earlier metamorphic event.Experimental work characterizing rate-limiting reaction mechanisms and their petrogenetic signatures in increasingly complex, higher-variance systems has facilitated the refinement of chemical fractionation and partial equilibration diffusion models necessary to more fully understand corona development. Through the application of quantitative physical diffusion models of coronas coupled with phase equilibria modelling utilizing calculated chemical potential gradients, it is possible to model the evolution of a corona through P -T -X-t space by continuous, steady-state and/or sequential, episodic reaction mechanisms. Most coronas in granulites form through a combination of these endmember reaction mechanisms, each characterized by distinct textural and chemical potential signatures with very different petrogenetic implications. An understanding of the inherent petrogenetic limitations of a reaction mechanism model is critical if an appropriate interpretation of P -T evolution is to be inferred from a corona. Since corona modelling employing calculated chemical potential gradie...

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Diffusion in Polycrystalline Materials: Grain Boundaries, Mathematical Models, and Experimental Data

Cited by 107 publications

References 124 publications

The influence of melt infiltration on the Li and Mg isotopic composition of the Horoman Peridotite Massif

The influence of melt infiltration on the Li and Mg isotopic composition of the Horoman Peridotite Massif

The legacy of crystal-plastic deformation in olivine: high-diffusivity pathways during serpentinization

Arrested development – a comparative analysis of multilayer corona textures in high-grade metamorphic rocks

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