A Late Cretaceous true polar wander oscillation

True polar wander (TPW), or planetary reorientation, is well documented for other planets and moons and for Earth at present day with satellites, but testing its prevalence in Earth's past is complicated by simultaneous motions due to plate tectonics. Debate has surrounded the existence of Late Cretaceous TPW ca. 84 million years ago (Ma). Classic palaeomagnetic data from the Scaglia Rossa limestone of Italy are the primary argument against the existence of ca. 84 Ma TPW. Here we present a new high-resolution palaeomagnetic record from two overlapping stratigraphic sections in Italy that provides evidence for a similar to 12 degrees TPW oscillation from 86 to 78Ma. This observation represents the most recent large-scale TPW documented and challenges the notion that the spin axis has been largely stable over the past 100 million years. The authors present a high-resolution palaeomagnetic record for a Late Cretaceous limestone in Italy. They claim that their record robustly shows a similar to 12 degrees true polar wander oscillation between 86 and 78Ma, with the greatest excursion at 84-82Ma.

Automated summary

A new high-resolution paleomagnetic record from two overlapping stratigraphic sections in Italy provides evidence for a 12-degree true polar wander oscillation from 86 to 78 million years ago, with the greatest excursion at 84-82 million years ago. This challenges the notion of the spin axis being largely stable over the past 100 million years and represents the most recent large-scale TPW documented.