A sea-level test for inertial interchange true polar wander events

The possibility of inertial interchange true polar wander (IITPW) events, i n which the rotation pole moves 90 degrees with respect to the solid Earth in a matter of similar to 10 Myr, has been discussed in the geophysical lit erature for more than three decades. Recent evidence for an IITPW event in Early Cambrian time has renewed interest in the issue; however, the veracit y of supporting palaeomagnetic evidence remains a matter of significant deb ate. We propose that sea-level variations driven by polar wander provide an important independent test for the occurrence of IITPW events. Our numeric al simulations of the response of a viscoelastic planet to an IITPW-induced forcing predict sea-level changes of up to 200 m, depending on the details of the earth model, the location of the site relative to the rotation path and the elapsed time for the reorientation of the pole. A preliminary comp arison of our predictions to Early-Middle Cambrian sea-level records for Au stralia, Laurentia and Baltica shows qualitative agreement. This comparison suggests that a definitive test for the Cambrian IITPW hypothesis is possi ble given a sufficiently accurate, and globally distributed, database of se a-level histories.