New research by geoscientists from the University of Florida and the Institut de Physique du Globe de Paris traces the origins of the Antarctic gravity hole (or the Antarctic Geoid Low) — the planet’s most extreme gravity anomaly — to slow, subterranean rock flows over tens of millions of years.
Evolution of the Antarctic Geoid Low. Image credit: P. Glišović & A.M. Forte, doi: 10.1038/s41598-025-28606-1.
“If we can better understand how Earth’s interior shapes gravity and sea levels, we gain insight into factors that may matter for the growth and stability of large ice sheets,” said University of Florida’s Professor Alessandro Forte.
“Caused by different densities of rock far beneath the Earth’s surface, these variations in gravity are small in absolute terms. But they can have particularly large effects on the oceans.”
“Where gravity is weaker, the ocean surface can sit slightly lower relative to Earth’s center because water flows away toward areas of stronger gravity.”
“Due to its gravity hole, the sea-surface height around Antarctica is measurably lower than it would otherwise be.”
In the new study, Professor Forte and Dr. Petar Glišović from the Paris Institute of Earth Physics mapped the Antarctic Geoid Low and revealed how it developed over the Cenozoic Era, the interval from 66 million years ago to present.
The researchers relied on an Earth-spanning scientific project that combined global earthquake recordings with physics-based modeling to reconstruct the 3D structure inside Earth.
“Imagine doing a CT scan of the whole Earth, but we don’t have X-rays like we do in a medical office,” Professor Forte said.
“We have earthquakes. Earthquake waves provide the ‘light’ that illuminates the interior of the planet.”
Accounting for all the rocks their earthquake waves could illuminate within Earth and physics-based modeling to predict the gravity pattern, the scientists reconstructed the gravitational map of the entire planet.
The reconstructed map closely matched the gold-standard gravitational data captured by satellites, supporting the realism of their underlying models.
Then came the hard part: turning the clock backward to see how the Antarctic Geoid Low developed over eons.
With sophisticated computer models, they used physics-based reconstructions to rewind the flow of rocks in the interior and track changes back 70 million years.
Those past snapshots revealed that the Antarctic Geoid Low started off weaker.
Then, between about 50 and 30 million years ago, the gravity hole started to gain strength.
The timing overlaps with major changes in Antarctica’s climate system, including the onset of widespread glaciation.
“We hope to test for a causal connection between this strengthening gravity hole and the ice sheets, using new modeling that links gravity, sea level and continental elevation changes,” Professor Forte said.
“The aim is to address one big question: How does our climate connect to what’s going on inside our planet?”
The study was published in December 2025 in the journal Scientific Reports.
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P. Glišović & A.M. Forte. 2025. Cenozoic evolution of Earth’s strongest geoid low illuminates mantle dynamics beneath Antarctica. Sci Rep 15, 45749; doi: 10.1038/s41598-025-28606-1
