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

Journal Article · Mon Apr 10 04:00:00 EDT 1989 · J. Geophys. Res.; (United States)

DOI:https://doi.org/10.1029/JB094iB04p04105· OSTI ID:6200691

Ryerson, F J; Durham, W B; Cherniak, D J; Lanford, W A

Oxygen self-diffusion experiments on single crystals of San Carlosolivine (/similar to/Fo/sub 92/) at 1200/degree/less than or equal to/ital T/less than or equal to1400 /degree/C, oxygen fugacities(/ital f//sub O2/) along the Ni-NiO and Fe-FeO buffers, and silica activityat the olivine-orthopyroxene buffer yielded results that follow therelationship /ital D/=2.6/times/10/sup /minus/10//ital f/ /sub O2//sup 0.21+-0.03/ exp (/minus/266+-11)(kJ mol/sup /minus/1///ital RT/), where/ital D/ is the diffusion coefficient in m/sup 2/ s/sup /minus/1/ and /ital f//sub O2/ is givenin pascals. The activation energy compares reasonably well with results forpure forsterite. The positive dependence of /ital f//sub O/sub 2// implies that theoxygen defect responsible for diffusion is an interstitial rather than a morestericaly reasonable oxygen vacancy. Diffusion of oxygen in other close-packedoxides has also shown a positive dependence on /ital f//sub O2/. The rate ofcreep of single-crystal olivine at fixed orthopyroxene activity also showsa positive /ital f//sub O2/ dependence. If oxygen interstitials should be shown tobe unimportant in oxygen diffusion in oxides, then coupled mechanisms such ascountervacancy diffusion must be appealed to in order to explain the positive/ital f//sub O2/ dependence. Such processes are rate-limited by the diffusion ofmetal vacancies which also display a positive /ital f//sub O2/ dependence inolivine. Compared with data for silicon diffusion in forsterite, our dataindicate that oxygen is not the slowest diffusing species in olivine.

• Research Organization: Lawrence Livermore National Laboratory, University of California, Livermore(US); Department of Physics, State University of New York at Albany
• OSTI ID: 6200691
• Journal Information: J. Geophys. Res.; (United States), Journal Name: J. Geophys. Res.; (United States) Vol. 94:B4; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580300* -- Mineralogy
Petrology
& Rock Mechanics-- (-1989)
ACTIVATION ENERGY
ALKALINE EARTH METAL COMPOUNDS
ATOM TRANSPORT
CREEP
DIFFUSION
ELEMENTS
ENERGY
IRON COMPOUNDS
IRON SILICATES
LATTICE PARAMETERS
MAGNESIUM COMPOUNDS
MAGNESIUM SILICATES
MECHANICAL PROPERTIES
MINERALS
NEUTRAL-PARTICLE TRANSPORT
NONMETALS
OLIVINE
OXYGEN
OXYGEN COMPOUNDS
RADIATION TRANSPORT
SELF-DIFFUSION
SILICATE MINERALS
SILICATES
SILICON COMPOUNDS
TRANSITION ELEMENT COMPOUNDS