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

B. J. Wanamaker, A. G. Duba

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59 Scopus citations

Abstract

The electrical conductivity along [100] of single crystal San Carlos olivine was measured as a function of temperature between 1100° and 1200° and oxygen fugacity between 10-6 and 10+0.5Pa (at 1200°C), and either with ("pyroxene-buffered') or without ("self-buffered') an added natural pyroxene buffer from a San Carlos lherzolite. Under these temperature and fO2 conditions, electrical conduction in the self-buffered sample is attributed to polarons (Fe+) and electrons eo) and in the pyroxene-buffered sample is attributed to polarons (Feo) and magnesium vacancies (V//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. This effect results from loss of iron from the olivine samples to the iridium electrodes. -from Authors

Original languageEnglish (US)
Pages (from-to)489-500
Number of pages12
JournalJournal of Geophysical Research
Volume98
Issue numberB1
DOIs
StatePublished - 1993

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