Mechanisms of electrical conductivity in olivine

Data on the electrical conductivity and the thermoelectric effect in single crystals indicate that the charge conduction mechanism in pure magnesium forsterite is electrons. The concentration of electrons is varied by controlling the number of oxygen vacancies through manipulation of the oxygen pressure. For iron bearing olivine, the conduction mechanism is by electron holes localized on an iron ion. Since iron strongly affects the creep process as well, oxidation of iron is probably accompanied by the production of magnesium vacancies.