Dipole Offset--The Time-Average Palaeomagnetic Field Over the Past 25 Million Years

The time-average palaeomagnetic field during Upper Tertiary times has as its source a dipole which is offset 285 ± 74 km north of the equatorial plane, but which remains axial. Modification of pole positions, taking the offset source dipole into account, suggests that no significant (> 1°) continental drift, polar wandering, or very long-term dipole wobble have been present during the Upper Tertiary. Four different analyses of the data have shown the dipole offset to be a real phenomenon, not due to peculiarities of the method of calculation.