For decades, Antarctica has been treated as a kind of frozen time capsule, a place where evidence of Earth’s deep past sits preserved, undisturbed, beneath layers of ice that have built up over millions of years. As per the study published in Nature Geoscience, scientists have now uncovered something remarkable within that buried record: an enormous, fan-shaped geological structure stretching across a huge swath of East Antarctica, hidden entirely from view beneath the ice.Researchers have named it the East Antarctic Fan-Shaped Basin Province, or EAFBP. It ties together a number of previously separate underground basins into one single, continent-scale system, and in doing so, it’s reshaping how scientists understand both the breakup of the ancient supercontinent Gondwana and how Antarctica’s ice sheet might behave as the planet continues to warm.
A hidden landscape beneath more than three kilometres of ice
More than 99% of Antarctica’s rock surface sits buried under ice, in places more than three kilometers thick. That makes direct geological fieldwork extremely challenging across most of the continent.To get around that, researchers turned to a mix of remote-sensing tools: radar capable of penetrating ice, gravity readings, magnetic surveys, seismic data, and digital models of the crust beneath. Piecing these datasets together, an international research team of scientists noticed something no one had fully connected before, a set of basins that all seemed to fan outward from roughly the same point near the South Pole, much like the ribs of an open hand fan.
Connecting Antarctica’s largest buried basins
Some of the individual pieces of this structure were already familiar to scientists. The Wilkes Basin and Aurora Basin had each been studied for years, as had the basin that holds Lake Vostok, the largest known lake sealed beneath ice anywhere on Earth.This discovery changes the way researchers interpret East Antarctica’s underground landscape. They appear to be pieces of one much larger tectonic structure, shaped by the same geological forces acting across the region at once. That reframes how researchers read East Antarctica’s underground map, not as scattered basins with separate histories, but as fragments of a single, continent-spanning event.
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How did this giant fan form
The leading explanation that researchers believe for how this structure formed is a process called distributed rotational extension. It happens when a section of continental crust stretches outward from a central anchor point rather than splitting cleanly along one fault line. Instead, the crust pulls apart in multiple directions at once, opening a series of wedge-shaped basins between zones of faulting.Researchers describe it almost like spreading fingers on a hand, or opening a folding fan, each segment pulling away from the center, carving out V-shaped depressions as it goes. Scientists studying the structure believe it may be among the largest and most well-preserved examples of this kind of crustal stretching.
A legacy of Gondwana’s breakup
The discovery also feeds into a much older story: the slow fragmentation of Gondwana, the supercontinent that once joined Antarctica with Australia, Africa, South America, and India.That breakup began around 180 million years ago. Antarctica and Australia held together longer than most of the other pieces, eventually splitting apart roughly 70 million years ago. Researchers now suspect the fan-shaped basin system may have played a role in that separation, weakening the crust in this region enough to make the eventual split easier. The precise timeline is still uncertain, but the structure appears to preserve a long stretch of crustal stretching tied to Gondwana’s slow unraveling.
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Challenging the view of East Antarctica
East Antarctica has long been regarded as one of the most geologically stable, least active pieces of crust on the planet, a craton that has largely sat still while the rest of the world’s plates shifted around it.This discovery complicates that picture. The scale and complexity of the fan-shaped province suggest East Antarctica went through far more intense crustal deformation in its past than previously assumed. Somewhere beneath the ice, the scars of that upheaval have simply been sitting, hidden and unread, until now.
Why this discovery matters today
The structure isn’t just a relic, it still shapes what happens on the surface today. The contours of this buried bedrock influence how ice moves across the continent, guiding the flow of glaciers and fast-moving ice streams above it.Because ice behavior is so closely tied to the landscape underneath it, mapping structures like this one gives scientists better raw material for modeling how Antarctica’s ice sheet might respond as temperatures rise, which in turn feeds directly into projections for global sea-level rise.Rather than closing the book on East Antarctica’s geological history, the discovery opens a new chapter of it. Researchers still don’t know exactly when the fan-shaped structure formed, or precisely what combination of forces drove such large-scale stretching across the crust. Filling in those gaps will likely take more detailed seismic surveys, refined geological modeling, and continued mapping of the terrain hidden beneath the ice. For now, the East Antarctic Fan-Shaped Basin Province stands as a reminder that even one of the most studied, most remote places on the planet still has enormous secrets locked away beneath its surface.
