Scientists have discovered a vast, previously unrecognized geological structure beneath East Antarctica’s ice sheet, linking known subglacial basins into a single, continent-scale system. Named the East Antarctic Fan-shaped Basin Province, it includes the Wilkes and Aurora basins and the basin holding Lake Vostok, the largest known subglacial lake. The structure likely formed through distributed rotational extension—a process where continental crust spreads outward from a central point, like fingers from a palm—during tectonic events tied to the breakup of the Gondwana supercontinent and the separation of Antarctica and Australia.

The discovery was made by combining data from subglacial topography, gravity and magnetic measurements, seismic records, and crustal models. Researchers used a reconstructed 'rebounded topography' model—simulating how the land would look without ice—to reveal the structure’s full extent and orientation. This deep tectonic feature may have played a role in continental rifting and continues to influence how ice flows over the bedrock today.

Understanding this hidden landscape is critical for predicting the behavior of Antarctica’s ice sheet, especially in regions vulnerable to climate change. The shape and depth of subglacial basins affect ice stability and the potential for accelerated melting. The study was led by Dr. Egidio Armadillo of the University of Genoa and supported by the Italian National Antarctic Research Program, with contributions from Dr. Guy Paxman of the Department of Geography.