TRUE POLAR WANDER AND SUPERCONTINENT CYCLES: IMPLICATIONS FOR EARTH PROPERTIES

The amplitude of true polar wander events is shown to occur in cycles out of phase with the formation of supercontinents over the past 3 Gyr. Associated with small-amplitude true polar wander, supercontinents act to stabilize the spin axis. Stabilization can be explained by reduced lithospheric elasticity and/or the triaxial (oblate) figure of the Earth, both of which are legacies of the supercontinent cycle. An excess triaxial ellipticity would only be expected to affect the first transition between supercontinents, whereas decreased lithospheric elasticity would have also influenced formation of the first supercontinent, if sizable enough. Similar to earlier conceptions of the relation between supercontinent and true polar wander cycles, long-lived true polar wander legacies follow behind peak amalgamation ages of once assembled supercontinents. However, while polar wander is indeed a supercontinental legacy, my analysis indicates that supercontinents counteract to limit its amplitude. My analysis indicates the presence of 4 supercontinents since 3 Ga and proposes that the triaxial Earth originates from the supercontinent cycle.