Test for polar wandering and some possible implications

Abstract

There are two magnetic methods of estimating drift of the lithosphere: the polar method, which measures motions relative to the pole arising from drift, polar wandering, or both, and the reversal method, which uses reversals of the field to measure the rate of spreading of the ocean floors away from the active ridges. Within the same segment of lithosphere these estimates are not in agreement as they should be if polar wandering had not occurred. The most likely causes of their disagreement are considered to be polar wandering and movement of the ridges. Changes of ridge pattern probably have occurred, but this explanation alone leads to unlikely tectonic situations. The rapid apparent polar movements observed in the upper Carboniferous and in the middle Tertiary of Australia are therefore considered to be evidence of rapid episodic polar wandering (about 20 cm/yr) superimposed on a background of comparatively slow crustal drift (1–3 cm/yr) whose pattern periodically changes. On this basis a general scheme relating diastrophism and geomagnetic variations is proposed.