A vast landscape lies concealed under more than three kilometers of ice in Antarctica. This feature links several major buried basins across the continent. Scientists are examining how this large fan-like formation developed as a result of Gondwana’s ancient separation. The finding challenges prior assumptions about East Antarctica’s stability. For many years, researchers viewed Antarctica as a preserved frozen archive holding records of Earth’s history beneath thick ice layers accumulated over millions of years. A study in Nature Geoscience reveals an immense fan-shaped geological feature spanning much of East Antarctica, completely concealed under the ice. Scientists have labeled it the East Antarctic Fan-Shaped Basin Province. This system unites several previously distinct underground basins into one large continental network, altering understandings of Gondwana’s breakup and the future behavior of Antarctica’s ice sheet amid rising global temperatures. Over 99 percent of Antarctica’s bedrock remains covered by ice exceeding three kilometers in depth, complicating direct study. Researchers combined ice-penetrating radar, gravity measurements, magnetic data, seismic readings, and crustal models to identify connected basins radiating outward from a central area near the South Pole. Individual basins such as Wilkes, Aurora, and the one containing Lake Vostok were already known, yet this work shows they form parts of a single tectonic system created by shared forces. The structure likely resulted from distributed rotational extension, where crust stretches outward from a fixed point in multiple directions, forming wedge-shaped depressions. This process resembles the opening of a fan and may represent one of the largest preserved examples. The feature also relates to Gondwana’s fragmentation starting 180 million years ago, with Antarctica and Australia separating about 70 million years ago. It may have weakened the crust and facilitated that split. East Antarctica was previously seen as a stable craton with minimal past deformation. The discovery indicates more significant crustal activity occurred than thought. The buried structure continues to affect surface ice movement by guiding glacier flow. Such mapping improves models of ice sheet response to warming and informs sea-level rise projections.
