Ancient sea levels show Earth's poles shifted during the dinosaur age

Researchers found Earth's geographic poles shifted during the age of the dinosaurs by studying patterns in ancient sea levels.

The work, led by Mathew Domeier at the University of Oslo in Norway, examined geological changes spanning the past 320 million years.

True polar wander happens when Earth's crust and mantle shift relative to its spin axis, changing the locations of the geographic poles without changing the angle of the spin axis itself.

Earlier studies based on magnetic traces in rocks had suggested these shifts were slow or negligible, but that method can give uncertain results.

The team used sea-level changes to track the shifts, because movement of Earth's mass can produce opposite sea-level patterns in the two hemispheres.

The findings challenge the idea that polar wander was always slow, and such shifts can move regions between latitudes and affect climate.

The research describes changes over the geological past; the supplied account does not say what further work is planned.