Abstract
True polar wander (TPW) or equatorial dipole (ED) field hypothesis have
the potential to decipher the Ediacaran paleomagnetic enigma, based on
the fast apparent polar wander (APW) rate revealed by the orthogonal
directional groups. However, determining the final solution is
challenging, as the conservatively estimated APW rates for both
hypotheses are consistent given current chronological constraints. A
precise APW rate is thus urgently needed. Fortunately, two distinct
poles and a transition zone were identified from the astronomical
calibrated Member 3 of the Doushantuo Formation in the Zhengjiatang
section, South China. The APW rate was precisely constrained to be 243 ±
17°/Myr, an extremely fast rate which excludes an origin of fast plate
motion or TPW. Based on the current global Ediacaran to Early Cambrian
paleomagnetic data, the ED field at ca. 596–570 Ma is suggested to be
responsible for the rapid directional change.