DIPOLAR REVERSAL STATES OF THE GEOMAGNETIC-FIELD AND CORE MANTLE DYNAMICS

Palaeomagnetic records from lavas suggest that at least two specific inclined dipolar field configurations have dominated the reversal process for the past ten million years. These long-lived states provide a way to explain directional rebounds, aborted reversals and the recording in sediments of what appear to be preferred longitudinal paths of the virtual geomagnetic pole. The polar orientations correlate with near-radial flux concentrations recognizable when today's field is stripped of its axial dipole, and with lower-mantle seismic anomalies, suggesting a tie to deep-Earth dynamics.