Electrical conductivity of San Carlos olivine along [100] under oxygen- and pyroxene-buffered conditions and implications for defect equilibria

Journal Article · Sun Jan 10 04:00:00 EST 1993 · Journal of Geophysical Research; (United States)

DOI:https://doi.org/10.1029/92JB01584· OSTI ID:6925005

Wanamaker, B J; Duba, A G ^[1]

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1. Lawrence Livermore National Lab., CA (United States)

The electrical conductivity along [100] of single crystal San Carlos olivine was measured as a function of temperature between 1100[degrees] and 1200[degrees]C and oxygen fugacity between 10[sup [minus]6] and 10[sup +0.5] Pa (at 1200[degrees]C), and either with (pyroxene-buffered) or without (self-buffered) an added natural pyroxene buffer from a San Carlos Iherzolite. Under these temperature and fO[sub 2] conditions, electrical conduction in the self-buffered sample is attributed to polarons (Fe[sup [sm bullet]]) and electrons (e[sup l]) and in the pyroxene-buffered sample is attributed to polarons (Fe[sup [sm bullet]]) and magnesium vacancies (V[double prime]mg). The conductivity of the pyroxene-buffered sample is lower than that of the self-buffered sample, primarily as a result of a decrease in the polaron concentration. The electrical conductivity of both samples was found to decrease irreversibly once the samples experienced an oxygen fugacity more reducing than approximately the wustite-magnetite buffer. Electron microprobe analyses indicate that this effect results from loss of iron from the olivine samples to the iridium electrodes. A series conduction model based on the observed compositional gradient adequately accounts for the magnitude of the irreversible conductivity decrease and limits the thickness of any surficial pyroxene phase to

• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 6925005
• Journal Information: Journal of Geophysical Research; (United States), Journal Name: Journal of Geophysical Research; (United States) Vol. 98:B1; ISSN JGREA2; ISSN 0148-0227
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360606* -- Other Materials-- Physical Properties-- (1992-)
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
CRYSTALS
EARTH MANTLE
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELECTRONS
ELEMENTARY PARTICLES
ELEMENTS
FERMIONS
LEPTONS
MINERALS
MONOCRYSTALS
NONMETALS
OLIVINE
OXYGEN
OXYGEN COMPOUNDS
PARTIAL PRESSURE
PHYSICAL PROPERTIES
POINT DEFECTS
POLARONS
PYROXENES
QUASI PARTICLES
SILICATE MINERALS
SILICATES
SILICON COMPOUNDS
TEMPERATURE DISTRIBUTION
TEMPERATURE RANGE
TEMPERATURE RANGE 1000-4000 K
VACANCIES