Ancient Seas Offer Clues to Earth’s Shifts Around Its Spin Axis

Seas that vanished millions of years ago have provided scientists with evidence suggesting that Earth repeatedly reoriented itself relative to its axis of rotation.

Rather than relying on the magnetic signals preserved in rocks, which act like fossilised compasses, the researchers traced the remnants of ancient seas to look for signs of those shifts.

The approach offers a different way to investigate how the planet’s orientation changed over its distant past. In this case, long-disappeared marine environments served as a record of movements on a planetary scale.

The findings suggest that Earth’s reorientation was not a one-off event. Instead, the traces left by ancient seas point to repeated shifts, adding another line of evidence to the study of the planet’s changing relationship with its spin axis.