A giant hidden gravity hole under antarctica is expanding and Earth’s interior may be driving it

Scientists Warn Antarctica’s Massive Gravity Dip Is Growing Stronger as Mantle Shifts Deep Below (Image: Canva)

Scientists have found that the Antarctic Geoid Low, a long-standing dip in Earth’s gravity field beneath Antarctica, has intensified over millions of years due to mantle convection and sinking tectonic slabs. Using earthquake data and computer models, researchers traced its evolution back 70 million years and linked it to shifts in Earth’s rotational axis known as True Polar Wander. The findings, published in Scientific Reports, suggest deep interior processes may have influenced sea levels and Antarctic ice sheet growth.

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Scientists report that a vast gravity dip beneath Antarctica is intensifying, shaped by deep mantle movements over millions of years, according to new research published in Scientific Reports.

Antarctic Geoid Low and Earth’s Gravity Field

Earth appears round, but gravity tells another story. Its gravitational field forms an uneven, lumpy shape. Scientists call this distorted form the geoid. One major depression sits beneath Antarctica today. This feature is known as the Antarctic Geoid Low. In this region gravity is slightly weaker. The difference at the surface remains very small. A person would notice only grams difference. Yet the feature reveals hidden planetary processes.

Gravity reflects how mass spreads inside Earth. Different rocks carry different densities and weights. These variations create subtle highs and lows. Maps exaggerate them for clearer scientific study. The geoid offers clues about unseen depths.

Earthquakes Map the Mantle Beneath Antarctica

Geophysicist Alessandro Forte of the University of Florida led the work. His colleague Petar Glišović from the Paris Institute of Earth Physics joined him. They used earthquake waves to scan Earth’s interior. Seismic waves shift speed through varied materials. The team built a three dimensional mantle model. They converted density data into a global geoid map. Satellite gravity data confirmed their model matched closely.

Researchers then examined the geoid’s deep history. They rewound mantle convection back seventy million years. Their simulation traced changes since the early Cenozoic. The model successfully reproduced today’s gravity pattern. It also matched shifts in Earth’s axis. Scientists call this motion True Polar Wander.

Mantle Convection, Polar Wander and Ice Sheets

Results show the gravity low is ancient. A depression existed near Antarctica for millions of years. Around fifty million years ago it shifted strongly. That timing matches a bend in polar wander. The model links the shift to sinking tectonic slabs. Subducted plates altered gravity from deep below. Rising hot mantle material later strengthened the anomaly.

Antarctic glaciation began about thirty four million years ago. Researchers suggest a possible connection with gravity changes. As the geoid lowered, local sea levels dropped. Lower seas may have aided ice growth. Forte said understanding interior forces clarifies ice stability. He noted gravity influences sea levels worldwide.

The findings highlight links between mantle flow and poles. Deep processes shape the surface over vast timescales. The gravity hollow remains subtle yet significant. The research appears in Scientific Reports.