Cooking Stones With The Force

Hangi rocks could reveal the magnetic history of the Earth going back hundreds of years, new research from Victoria University suggests. The findings, which were presented at the annual meeting of the American Geophysical Union in San Francisco, say the stones became so hot that the minerals in them with magnetic properties would have aligned with the Earth’s magnetic field at the time. The team experimented with modern-day hangis, heating them and then placing a compass atop them to see how the magnetic field realigned once they cooled. “We have very good palaeomagnetic data from across the world recording field strength and direction – especially in the Northern Hemisphere,” one of the study authors, Gillian Turner said. “The southwest Pacific is the gap, and in order to complete global models, we’re rather desperate for good, high-resolved data from our part of the world.”