Сериальное издание: Russian Geology and Geophysics
Страницы: 263-271
Аннотация
Phase change of dielectric magnesiowustite in the lower mantle may leave signatures in geomagnetic records of the globally distributed array of observatories. We investigate theoretically which may be the contribution of magnesiowustite metallization to geomagnetic data and how the variations of magnetic susceptibility associated with this phase change may influence the Earth's field. The modeling is performed using spherical harmonic analysis (SHA) of mantle electromagnetic (EM) responses in observatory geomagnetic data at periods of decades, 11 years, 1 year, and 27 days. The existence of a lower mantle conductor is checked against monthly means of real observatory records from 1920 through 2009 obtained by preliminary processing
