Point defect diffusivites in San Carlos olivine derived from reequilibration of electrical conductivity following changes in oxygen fugacity

摘要: The time dependence of electrical conductivity following step changes in oxygen fugacity has been used to deduce the diffusivities dominant point defects pyroxene-buffered San Carlos olivine. Nonlinear least squares fits data indicate that two relaxation times (τ) are present conductivity-time records. effective diffusivity calculated from slower τ agrees with values reported for chemical metal vacancies (VMe‖). faster coincides measured analogous strain rate (έ) fO2. This tentatively associated silicon (VSi‖‖). These results imply on tetrahedral and octahedral sublattices olivine may reequilibrate independently. Furthermore, resulting thermodynamic conditions initiated by reequilibration these defects.