Two colossal, ultra-hot rock formations, positioned 2,900 kilometers beneath the Earth’s surface in Africa and the Pacific Ocean, have influenced Earth’s magnetic field for millions of years, according to groundbreaking research led by Professor Andy Biggin from the University of Liverpool.
Giant superheated solid masses at the Earth’s mantle base impact the liquid outer core. Image credit: Biggin et al., doi: 10.1038/s41561-025-01910-1.
Measuring ancient magnetic fields and simulating their generation presents significant technical challenges.
To explore these deep Earth features, Professor Biggin and his team used paleomagnetic data in conjunction with advanced Earth Dynamo simulations. The flow of liquid iron in the outer core generates Earth’s magnetic field, akin to a wind turbine producing electricity.
Numerical models reconstructed critical insights about magnetic field behavior over the past 265 million years.
Even with supercomputers, conducting these long-term simulations poses enormous computational challenges.
The findings showed that temperature at the upper layer of the outer core is not uniform.
Instead, localized hot areas are accompanied by continent-sized rock structures exhibiting significant thermal contrasts.
Some regions of the magnetic field were found to remain relatively stable over hundreds of millions of years, while others displayed considerable changes over time.
“These results indicate pronounced temperature variations in the rocky mantle just above the core, suggesting that beneath hotter regions, liquid iron in the core may be stagnant, rather than flowing intensely as observed beneath colder areas,” Professor Biggin stated.
“Gaining such insights into the deep Earth over extensive timescales enhances the case for utilizing ancient magnetic records to comprehend both the dynamic evolution and stable properties of deep Earth.”
“These discoveries also bear significant implications for understanding ancient continents, including the formation and breakup of Pangea, and could help address long-standing uncertainties in ancient climate studies, paleontology, and natural resource formation.”
“It has been hypothesized that, on average, Earth’s magnetic field acts as a perfect bar magnet aligned with the planet’s rotation axis in these regions.”
“Our findings suggest that this may not be entirely accurate.”
This study is published in today’s edition of Nature Earth Science.
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AJ Biggin et al. Inhomogeneities in the mantle influenced Earth’s ancient magnetic field. Nature Earth Science published online on February 3, 2026. doi: 10.1038/s41561-025-01910-1
Source: www.sci.news
