A study in Nature Geoscience has identified a giant fan-shaped province of buried basins beneath the East Antarctic Ice Sheet. The structure connects some of the continent’s best-known hidden landscapes and may preserve a deep record of the breakup of Gondwana.
The research team named the feature the East Antarctic Fan-Shaped Basin Province. It lies beneath a vast region where ice covers the bedrock and hides the shape of the continent below. By combining sub-ice topography with gravity, magnetic, seismic and modeling evidence, the researchers argue that several basins once viewed separately belong to one continent-scale tectonic system.
The finding changes the way scientists can read East Antarctica’s buried terrain. The province includes the Wilkes Basin, the Aurora Basin and the basin that hosts Lake Vostok. These features appear to radiate from a point near the South Pole, forming a pattern that resembles a handheld fan.
A Hidden Basin Province Under the Ice
The Antarctic Ice Sheet covers more than 99% of the continent’s bedrock. That ice mask has long made East Antarctica one of Earth’s hardest places to study. Aircraft, satellites and geophysical surveys have gradually revealed mountains, valleys, lakes and troughs beneath the surface.
In the new study, the team focused on a wide low-elevation sector of East Antarctica. This region stretches from Prydz Bay toward the Transantarctic Mountains. It also reaches inland toward high southern latitudes, where the buried basins narrow toward a common area.
Researchers describe the province as “a semi-continental-sized, fan-shaped physiographic unit” in the study abstract. That phrase matters because it frames the basins as parts of a single landscape. The pattern spans enough of the continent to affect how scientists think about East Antarctica’s structure.
Many of the basins have V-shaped outlines. Their long axes point roughly north to south. When the researchers traced the edges of these basins across the curved surface of the Earth, the lines converged near the South Pole.
This geometry gave the team a way to connect surface shape with deep tectonic history. The basins sit beneath thick ice today. Their arrangement suggests that the crust below them experienced a coordinated stretching process in the deep past.
How Antarctica’s Crust Spread Like a Fan
The study points to rotational extension as the process that formed the fan. In this type of deformation, crust stretches outward around a pivot area. The result can resemble fingers spreading from a fixed base.
In East Antarctica, those “fingers” are expressed as large buried basins. The spaces between them hold the triangular and V-shaped geometry that caught the researchers’ attention. The team used subglacial topography to trace the shape and geophysical data to test whether the pattern continued into the crust.
The model suggests that the province formed through distributed intraplate deformation. That means the stretching happened within a continental plate, across a broad region. It was spread through the interior rather than confined to a single narrow boundary.
The researchers fitted basin edges to great-circle paths on the globe. This helped estimate a pivot point near 86.4 degrees south and 129.9 degrees east. That location sits close to the South Pole and supports the idea that the basins radiate from a common tectonic center.
Gravity, magnetic and seismic information added another layer of evidence. These datasets can reveal changes in crustal thickness and hidden boundaries between crustal blocks. Together, they helped the team argue that the fan shape reflects deeper geology rather than surface coincidence.
A Possible Link to Gondwana’s Breakup
Gondwana was the ancient supercontinent that included Antarctica, Australia, Africa, South America, India and other landmasses. Its breakup reshaped the Southern Hemisphere over many millions of years. East Antarctica’s hidden fan may record part of that long tectonic story.
The Nature Geoscience study proposes that the fan-like landscape formed before the final stages of Gondwana breakup. The researchers connect the deformation to the separation between Antarctica and Australia. That event produced a major continental margin along East Antarctica.
According to the study, the northern edge of the fan may have created a zone of weakness in the lithosphere. The lithosphere is Earth’s rigid outer shell. A weakened region could have guided the propagation of rifting as Antarctica and Australia separated.
The team also suggests that the fan’s geometry helped shape the semi-circular form of the continental margins in this sector. That idea links a buried inland structure to the outline of the continent’s edge. It also gives the fan a possible role in a major event of plate tectonics.
The timing remains a central question. The structure may have developed through more than one phase. Better age constraints would help show how closely the fan’s development matches the breakup sequence of Gondwana and the later separation of Antarctica from Australia.
Buried Clues From Lake Vostok to the Transantarctic Mountains
Some of East Antarctica’s most famous hidden features may fit into the same tectonic picture. Lake Vostok sits beneath the ice sheet in a deep basin. Wilkes and Aurora are also enormous subglacial basins that have drawn attention because of their shape and possible influence on ice flow.
The study proposes that these features belong to the East Antarctic Fan-Shaped Basin Province. That interpretation gives them a shared origin. Their positions and orientations appear consistent with the broad fan structure.
To the west, the researchers link the province to the Gamburtsev Mountains. These mountains are buried beneath the ice and are often compared in scale to the European Alps. The study suggests that compression associated with the fan’s formation may have contributed to their uplift.
To the east, the fan model includes the Transantarctic Mountains. The researchers describe a clockwise rotation of the northernmost segment by about 20 degrees. In their interpretation, that rotation helped segment the mountain chain into blocks with different uplift histories.
These connections give the fan model continental reach. A single deformation process may help explain basins, buried mountains, rotated mountain segments and the shape of East Antarctica’s edge. Each piece adds another clue to a landscape that remains mostly sealed beneath ice.
Why the Discovery Matters for Ice Flow
The shape of bedrock matters for ice. Glaciers and ice streams follow slopes, troughs and basins as they move toward the coast. A continent-scale basin province can guide that movement over long periods.
The study says these processes have “influenced the present-day East Antarctica sub-ice landscape.” That influence includes the development of glacial troughs and outlet glaciers. In practical terms, the buried fan may help determine where ice flows more easily.
East Antarctica contains a vast amount of frozen water. Scientists study its bedrock because the shape of the land below the ice can affect ice-sheet behavior. Deep basins may help channel flow, while highlands can divide or slow it.
The new research adds a tectonic origin story to that hidden geography. The basins beneath the ice may have formed long before the modern ice sheet. Yet their shapes continue to matter because the ice sheet sits directly on top of them.
This connection between ancient tectonics and present ice flow is one reason Antarctica’s buried geology attracts so much attention. Climate, ocean heat, snow accumulation and ice physics all shape the ice sheet. Bedrock supplies the stage on which those forces act.
What Scientists Need to Test Next
The Nature Geoscience team presents the fan-shaped province as a model that can be tested further. The geometry is striking and the geophysical evidence supports a coherent tectonic interpretation. The next challenge is pinning down when the deformation happened.
Dating buried Antarctic landscapes is difficult. Much of the relevant rock lies beneath kilometers of ice. Researchers often have to combine indirect clues from geophysics, offshore geology, plate reconstructions and exposed mountain ranges.
Future work could refine the timing of basin formation and test whether the fan developed in several stages. More detailed seismic imaging may also help map crustal boundaries below the ice. Improved topographic data could sharpen the outlines of individual basins.
The study also raises questions about what drove the deformation. Rotational extension needs a broader tectonic context. Interactions among inherited crustal blocks, rifting forces and Gondwana’s breakup may all have played a role.
Antarctica still holds many geological secrets because its bedrock is so thoroughly hidden. The newly named fan-shaped province shows how much can be learned by combining ice-penetrating maps with measurements of gravity, magnetism and crustal structure. Beneath the ice, East Antarctica appears to preserve a giant tectonic fingerprint from a changing planet.
