Researchers from Italy, Switzerland, Germany, and the UK have made a groundbreaking discovery by integrating seismic, gravity, and topographic data. They found that numerous prominent subglacial basins in East Antarctica belong to a singular fan-shaped geological province that traces its origins back to ancient continental expansion.
A structural frame interpreted as a fault-controlled basin in the newly identified East Antarctic fan basin. Image credit: Armadillo et al., doi: 10.1038/s41561-026-01991-6.
“The Antarctic bedrock is largely uncovered by the Antarctic Ice Sheet, which covers over 99% of the continent,” stated lead author Dr. Egidio Armadillo of the University of Genoa and his colleagues.
“Recent international efforts utilizing radio-echo sounding data have uncovered vast subglacial topographic features with increasing clarity, highlighting a significant, low-elevation region of East Antarctica that stretches from Prydz Bay to the Transantarctic Mountains and extends inland to 85 degrees south latitude.”
“In this area, most large subglacial basins exhibit a V-shaped profile and are oriented in a north-south direction.”
“Additionally, the 2,000 km long Antarctic coastline and the continent-ocean boundary limit the northern sector, presenting a distinct semi-circular arc shape.”
“On a semi-continental scale, the landscape resembles a handheld fan, with a concentration near the South Pole.”
“We propose that this entire geographical region constitutes a single geographic unit, naming it the East Antarctic Fan Basin (EAFBP).”
The EAFBP includes some of Antarctica’s most significant subglacial features, notably the Wilkes Basin and the Aurora Basin, which houses Lake Vostok, the largest known subglacial lake on Earth.
Analysis indicates that this structure formed through a process known as dispersive rotational extension.
This mechanism describes how continental crust expands from a central point, producing a fan-like pattern akin to a hand with the thumb as a fixed point while the fingers splay and elongate.
The gaps between the fingers symbolize triangular basins formed as the structure opens.
Scientists suggest that the EAFBP may represent one of the most extensive examples of rotational extension documented in continental crust.
This phenomenon likely evolved through multiple tectonic events linked to the development of the Gondwana supercontinent and the subsequent separation of Antarctica and Australia, potentially influencing these separations.
The discovery prompts further investigation into the structure’s age and the geodynamic processes responsible for its formation.
Moreover, its implications extend beyond historical context.
“The bedrock shape concealed beneath the ice sheet continuously impacts ice flow today, regulating the distribution of subglacial basins and lakes,” the authors emphasized.
“This may also affect the stability of segments of the Antarctic ice sheet that are particularly vulnerable to climate change.”
For further details, refer to the study published in the June 3rd issue of Nature Earth Science.
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E. Armadillo et al. A fan-shaped subglacial basin province in East Antarctica formed by rotational extension. Nature Earth Science published online on June 3, 2026. doi: 10.1038/s41561-026-01991-6
Source: www.sci.news
