The Breakup of Gondwana Over 100 Million Years Ago May Be Why Antarctica Has Ice Today - Eos
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Under the ice, Antarctica’s topography is marked by multiple mountain ranges that formed and uplifted over millions of years. Credit: Dr Guy Paxman, Durham University, CC BY-NC 4.0
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Hundreds of millions of years ago, Antarctica’s climate resembled a tropical forest. It was humid, warm, and abundant in plant and animal life.
But then, something shifted. Around 34 million years ago, glaciers developed over East Antarctica, eventually forming the icy, cold landscape we know today. But what sparked the formation of these glaciers has been somewhat of a mystery.
“It’s really quite cool—we could be seeing this threshold whereby the interior of Antarctica became way more susceptible to forming an ice sheet.”
The initiation, growth, and stabilization of the East Antarctic Ice Sheet “is a very important problem that I don’t think is well understood,” said John Goodge, a geologist at the University of Minnesota Duluth who studies Antarctica’s past.
A new study offers a new explanation: Land uplift that resulted from a rift during the Jurassic period, 201–143 million years ago, may have created a high-elevation site with conditions ripe for glacier formation tens of millions of years later.
“About 50 million years ago, we had a major change in the highlands because of the uplift,” said Thomas Gernon, an Earth scientist at the University of Southampton and lead author of the new study, which was published in Science. “It’s really quite cool—we could be seeing this threshold whereby the interior of Antarctica became way more susceptible to forming an ice sheet.”
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A new study suggests that over tens of millions of years, mantle waves caused uplift in portions of East Antarctica. Click image for larger version. Credit: Dr Thea Hincks, University of Southampton
The new research “has really highlighted the importance of tectonics” in driving changes such as ice sheet growth, said Goodge, who was not involved in the new study. “This is a nice way to not only recognize the multiple drivers [of glaciation] but also to look back on the tectonic history of East Antarctica to see what could have conceivably kicked things off.”
Clues from Africa
Gernon didn’t set out, at first, to study the origins of the East Antarctic Ice Sheet. Instead, he wanted to see whether Antarctica’s geologic history matched that of another continent: Africa. In a 2024 study published in Nature, he and others reported that southern Africa’s high escarpments and plateaus were the result of so-called mantle waves spurred by tectonic rifting events during the breakup of the Gondwana supercontinent in the Jurassic period. These mantle waves spread beneath continents, radiating out from rifting events. Among other effects, mantle waves can remove rock from the lithosphere over millions of years, allowing the remaining rock to lift up.
“When you have bits of the continent falling off, you get a surface response—you get uplift, [erosion], and in the case of [southern] Africa, you get this anomalously high elevation,” Gernon said.
Gernon wondered whether the mantle wave process could also apply to Antarctica, which bordered what is now southern Africa within Gondwana.
He bought a paper map of Antarctic topography and was immediately struck by the similarities. Just as he’d seen in South Africa, a portion of the Antarctic coastline called Queen Maud Land (Dronning Maud Land) had a steep escarpment up against a large, high-elevation plateau that eventually ran into the Gamburtsev Subglacial Mountains, an enigmatic mountain range long thought to be the origin site of the East Antarctic Ice Sheet.
The new study suggests that uplift of East Antarctica, especially beneath the Gamburtsev Subglacial Mountains, created conditions favorable for the formation of the East Antarctic Ice Sheet. Credit: Prof Thomas Gernon, University of Southampton (created with Datawrapper)
“I could not believe what I saw,” Gernon said. “I thought, ‘It looks just like Africa.’”
It seemed that the landscape processes affecting both continents “were very much similar” as a result of rifting and the mantle wave process.
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