Geology Club Seminar

Debate has surrounded the existence of Late Cretaceous rapid true polar wander (TPW) ca. 84 million years ago (Ma). Classic paleomagnetic data from the Scaglia Rossa limestone of Gubbio and Moria, Italy, in the Umbrian Apennines, are the primary argument against the existence of Late Cretaceous TPW. We present a new high-resolution paleomagnetic record confirmed at two overlapping stratigraphic sections in Apiro and Furlo that provide evidence for a ~10˚ TPW oscillation from 86-79 Ma implying a rate of 2.9˚ Myr^-1, almost four times faster than present-day TPW. Always directed westward, TPW excursions since the breakup of supercontinent Pangea may hint at the mantle convective mass anomalies associated with plate tectonics triggering reorientation of the geographic pole.