A vast geological structure hidden beneath the East Antarctic Ice Sheet is offering scientists a new way to understand both Antarctica’s ancient past and the behaviour of its ice today.
An international research team led by the University of Genoa, with support from Italy’s National Antarctic Research Programme (PNRA), has identified what they call the East Antarctic Fan-shaped Basin Province (EAFBP). The discovery, published in Nature Geoscience, links several of Antarctica’s best-known subglacial features, including the Wilkes Basin, Aurora Basin and the basin containing Lake Vostok, into a single continent-scale geological system.
The newly recognised province lies beneath ice more than three kilometres thick in places. While the individual basins have been studied for years, researchers have now shown that they form part of a much larger, connected structure shaped like a handheld fan.
To reveal the hidden landscape, the team combined subglacial topography with gravity, magnetic and seismic data, along with models of Antarctica’s crust and lithosphere. Their analysis suggests the structure formed through a process known as distributed rotational extension, in which continental crust stretches outward from a central point. Researchers compare the pattern to a hand opening, with the “fingers” represented by the basin systems radiating across East Antarctica.
The findings may help explain events linked to the evolution of the supercontinent Gondwana and the eventual separation of Antarctica from Australia. The fan-shaped province could represent one of the largest known examples of rotational extension in continental crust.
The significance extends well beyond geology. The shape of the bedrock beneath Antarctica continues to influence how ice flows across the continent, directing the movement of ice and controlling the distribution of subglacial lakes and basins. As scientists work to improve projections of future ice-sheet change, understanding the architecture hidden beneath the ice is becoming increasingly important.