Scientists have found a massive fan-shaped structure buried beneath East Antarctica, connecting some of the continent’s most famous subglacial basins into one huge hidden formation. The ice above it can be more than three kilometers thick, hiding one of the largest examples of continental stretching ever recorded.
The formation is called the East Antarctic Fan-shaped Basin Province and includes the Wilkes basin, the Aurora basin, and the basin that contains Lake Vostok, the biggest known subglacial lake on Earth. According to the researchers, while each basin has been studied on its own before, this is the first time they have been recognized as part of a single, massive system.
This discovery is not just a map update. Its shape affects how ice moves across the continent and how subglacial lakes are spread out. According to the team, this could have an impact on the stability of parts of the Antarctic Ice Sheet. The fan-shaped province formed through a process called rotational extension, where the crust spreads outward from a central point, creating the hand-like pattern we see today.
Mapping East Antarctica’s Hidden Basins
The fan-shaped province is made of several enormous subglacial basins arranged like an open hand, as explained by a statement publishec by Durham University. The palm acts as a central point while the fingers spread out. The triangular gaps between the fingers mark the basins themselves.
Some of Antarctica’s most famous features are part of this system. Lake Vostok, for example, sits under thick ice and had been studied separately, but its connection to the Wilkes and Aurora basins was not known until now.
Recognizing the basins as one structure helps scientists see patterns of crust stretching that were hidden before. It also gives a clearer picture of what lies beneath the ice.
How Rotational Extension Created The Fan
Researchers say the province formed through distributed rotational extension, where the continental crust spreads out from a central pivot point. The fan shape shows where the crust was stretched and thinned over time. According to the study, avaliable on Nature Geoscience, this might be one of the largest examples of rotational extension ever recorded in continental crust.
The province may have developed through several tectonic phases linked to the Gondwana supercontinentand the later split between Antarctica and Australia. This shows that the fan-shaped basins not only record ancient tectonic history but might also have influenced how the continents moved apart.
Ice Flow on Rising Land
To understand the structure, scientists combined subglacial maps with gravity, magnetic, and seismic data, and models of the crust and lithosphere. As Dr. Guy Paxman, part of the team, explained if all the ice were removed, the land beneath East Antarctica would rise by up to one kilometer. This is called rebounded topography.
This helped the researchers see the orientation and height of the basins. The study team added that the structure still affects ice flow and where subglacial lakes form today. The discovery connects ancient tectonic forces to the way the ice sheet behaves now.
