The observed motion of continents relative to the Earth's spin axis may be due either to rotation of the entire Earth relative to its spin axis ('true polar wander'), or to the motion of individual tectonic plates. To distinguish between these processes, the global average of continental motion and rotation in a palaeomagnetic reference frame over the past 320 Myr was computed and two components were identified: a steady northward motion and, during certain time intervals, clockwise and counterclockwise rotations, which they interpret as true polar wander.
- Bernhard Steinberger
- Trond H. Torsvik
