Do virtual geomagnetic poles follow preferred paths during geomagnetic reversals?

VIRTUAL geomagnetic poles (VGPs) recorded in sediments during reversals of the Earth's magnetic field show an apparent preference for two antipodal sectors of longitude1–3, not only in records of the same reversal from different sites, but also in records of different reversals. If preferred bands really have persisted from one reversal to the next, this would imply that the mantle exerts a significant control over the reversal process4. Here we analyse the available database of reversal records from the past 12 Myr, using a statistical test specifically designed to test the hypothesis of two preferred antipodal longitudinal bands. Our analysis shows that the records, taken as a group of independent observations, do show an overall preference for two antipodal longitudinal bands. However, the site longitudes are also strongly grouped5, and a comparison of the transitional VGP longitudes with site longitudes shows an unlikely grouping under the hypothesis of a genuine geographical preference for transitional VGPs. We conclude that it is premature to accept the hypothesis of mantle control over the core during geomagnetic reversals.