4. Diffusion Measurements: Experimental Methods

Ryerson, Frederick J.

doi:10.1016/s0076-695x(08)60585-2

Cited by 15 publications

(8 citation statements)

References 90 publications

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“…These and other important features of diffusion experiments are described in Ryerson [141] (20) and fit by a straight line on a graph of log D (m2/s) as a function of l/T (K-i) [147,Chap. 21.…”

Section: Diffusion Coefficientsmentioning

confidence: 99%

Diffusion Data for Silicate Minerals, Glasses, and Liquids

Brady

2013

AGU Reference Shelf

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Section: Diffusion Coefficientsmentioning

confidence: 99%

Diffusion Data for Silicate Minerals, Glasses, and Liquids

Brady

2013

AGU Reference Shelf

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“…Experimental techniques to determine diffusion coefficients of ions, atoms, and molecules in silicate melts are described in Ryerson (1987), Watson and Dohmen (2010) and Behrens (2010). Information about analytical techniques to measure diffusion profiles can be found in Cherniak et al (2010).…”

Section: Sulfur Diffusion Studiesmentioning

confidence: 99%

Diffusion and Redox Reactions of Sulfur in Silicate Melts

Behrens

Stelling

2011

Reviews in Mineralogy and Geochemistry

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“…The purpose of the short ion-milling step was to remove this last damaged layer. Work on other oxide crystals has also amply demonstrated the possible effects of surface preparation on measured diffusion coefficients (see Ryerson [1987] for a limited by dislocation climb, reequilibration of minority as well as majority defects must occur within the observed relaxation time. Electrical conductivity is also controlled by the concentration of majority defects; conductivity measurements in olivine attain new equilibrium values in times typically less than 1 hour for temperatures above 1200øC following a change in fo2 [Schock et al, 1989].…”

Section: Pretreatment Of Olivine Samplesmentioning

confidence: 99%

Oxygen diffusion in olivine: Effect of oxygen fugacity and implications for creep

Ryerson¹,

Durham²,

Cherniak³

et al. 1989

J. Geophys. Res.

140

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Oxygen self‐diffusion experiments on single crystals of San Carlos olivine (∼Fo92) at 1200° ≤ T ≤ 1400°C, oxygen fugacities (ƒO2) along the Ni‐NiO and Fe‐FeO buffers, and silica activity at the olivine‐orthopyroxene buffer yielded results that follow the relationship D = 2.6 × 10−10 ƒO20.21±0.03 exp [−266±11 (kJ mol−1/RT)], where D is the diffusion coefficient in m2 s−1 and ƒO2 is given in pascals. The activation energy compares reasonably well with results for pure forsterite. The positive dependence of ƒO2 implies that the oxygen defect responsible for diffusion is an interstitial rather than a more sterically reasonable oxygen vacancy. Diffusion of oxygen in other close‐packed oxides has also shown a positive dependence on ƒO2. The rate of creep of single‐crystal olivine at fixed orthopyroxene activity also shows a positive ƒO2 dependence. If oxygen interstitials should be shown to be unimportant in oxygen diffusion in oxides, then coupled mechanisms such as countervacancy diffusion must be appealed to in order to explain the positive ƒO2 dependence. Such processes are rate‐limited by the diffusion of metal vacancies which also display a positive ƒO2 dependence in olivine. Compared with data for silicon diffusion in forsterite, our data indicate that oxygen is not the slowest diffusing species in olivine. The activation energy for oxygen diffusion is also low compared to that obtained in a majority of measurements of creep in single‐crystal olivine. Hence if oxygen diffusion contributes to the control of creep in olivine, it must be coupled to another process having a nonzero activation energy. A subinvestigation of the rate of sublimation from polished olivine surfaces, using a high‐resolution thermal balance, showed surface erosion rates at 1300°C of 0.13±0.10 nm/h. Such values are far too slow to noticeably affect our diffusion measurements at temperatures ≤1400°C.

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4. Diffusion Measurements: Experimental Methods

Cited by 15 publications

References 90 publications

Diffusion Data for Silicate Minerals, Glasses, and Liquids

Diffusion Data for Silicate Minerals, Glasses, and Liquids

Diffusion and Redox Reactions of Sulfur in Silicate Melts

Oxygen diffusion in olivine: Effect of oxygen fugacity and implications for creep

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