True Polar Wander - Theoretical Constraints



Ture polar wander (TPW) is the idea that the Earth can exhibit a solid-body rotation relative to its spin axis. Another way of describing this is to say the geographic axes move relative to the rotational axes. For example, 90 degrees of TPW could result in Antarctica moving to the equatorial region, Africa moving to the pole, and all other geographic features moving accordingly.

It has been assumed (by many authors) that TPW can occur relatively fast and therefore explain some enigmatic paleomagnetic data. However, theoretical analysis (Tsai and Stevenson, JGR 2007) of a simplified Earth with a sinusoidally varying moment of inertia shows that the maximum amount of TPW is limited to approximately 61 degrees in 100 million years and 8 degrees in 10 million years.