Study Traces Origins of Antarctica's Gravity Anomaly to Deep Earth Dynamics

Scientists from the University of Florida and the Institut de Physique du Globe de Paris have traced the origins of the Antarctic Geoid Low, Earth's most pronounced gravity anomaly, to gradual subterranean rock movements over tens of millions of years. This research offers insights into the interplay between Earth's internal dynamics and surface gravity variations.

Professor Alessandro Forte of the University of Florida emphasized the significance of understanding Earth's interior in relation to gravity and sea levels, noting that such knowledge can inform studies on the growth and stability of large ice sheets. He explained that variations in gravity, though minor in absolute terms, can notably influence ocean behavior, as water tends to move toward areas of stronger gravity, leading to measurable differences in sea-surface height around Antarctica.

The study, published in Scientific Reports, involved mapping the Antarctic Geoid Low's development over the Cenozoic Era, spanning from 66 million years ago to the present. Researchers utilized global earthquake recordings and physics-based modeling to reconstruct Earth's three-dimensional internal structure. Forte likened this process to performing a CT scan of the entire planet, using earthquake waves to illuminate its interior.

By analyzing the reconstructed gravitational map, the team observed that the Antarctic Geoid Low was initially weaker but began to intensify between 50 and 30 million years ago. This period coincides with significant climatic shifts in Antarctica, including the onset of widespread glaciation. Forte expressed interest in further exploring potential causal connections between the strengthening gravity anomaly and the development of ice sheets, aiming to address broader questions about the relationship between Earth's internal processes and climate.