Geomagnetic 100-kyr variation excited by a change in the Earth's orbital eccentricity

摘要

Geomagnetic secular variations on a time scale of 10-100 kyr have important implications regarding the energy source of the geomagnetic field. Some high-quality paleomagnetic records from marine sediment cores show quasi-periodic variations having a time scale close to that of the Earth's orbital eccentricity. We analyzed a paleomagnetic record of core MD982185 from the equatorial Pacific and the Earth's eccentricity for the last 2.2 m.y. utilizing wavelet analysis. Variations in the geomagnetic vertical component were synchronous with those in the first derivative of the eccentricity, implying that the geomagnetic variations are excited by changes in the eccentricity.