Uplift Beginning in the Jurassic Era and Accelerated in the Eocene Period Created High Mountains in East Antarctica, Resulting in Snowfall and Ice Sheet Formation Millions of Years Before Arctic Ice Accumulation: This Happened When the Earth was 5 Degrees Celsius Warmer Than Today

     A new paper published in the journal Science uncovers why Antarctica underwent ice accumulation millions of years before the Arctic and did so when the Earth’s temperatures were 5 degrees Celsius warmer than today. The study concludes that the formation of an escarpment, plateau, and mountain region in East Antarctica created the high ground needed for snow and ice to accumulate. The process began when Antarctica and Africa began to separate in the Jurassic Period, 201–143 million years ago. Well over 100 million years later, around 40 million years ago during the Eocene, ice began to accumulate in East Antarctica as alpine glaciation. By 34 million years ago at the onset of the Oligocene, after a vastly long period of gradual uplift, which resulted in high mountains being formed, with conditions favorable for snow due to the elevation, the ice sheet began to expand. This happened while the surrounding oceans were surprisingly warm.

     The research team was led by the University of Southampton, working with colleagues at Durham University, GFZ Helmholtz Center for Geosciences in Germany, the University of Potsdam in Germany, Utrecht University in the Netherlands, and the University of Florence in Italy. They used computations to model the long history of the uplift. The team concluded that “mantle waves” were responsible for the uplift.

     According to Phys.org:

“Mantle waves are a recently discovered phenomenon by Gernon's team. They spread under continents when tectonic plates break apart and have been shown to cause the eruption of diamond volcanoes and mysterious phases of uplift within continents.”

“The team's simulations revealed that by about 45 million years ago, much of the East Antarctic landscape had risen above the critical elevation—about 2 km—needed for mountain glaciers to form and expand, eventually merging into the East Antarctic Ice Sheet.”

“The research helps explain the striking asymmetry in polar ice in the past. Antarctica became glaciated about 34 million years ago, but large Northern Hemisphere ice sheets did not assemble until approximately the past 5 million years.”  

     It is true that declining atmospheric CO2 levels are thought to have been the initial trigger for Antarctic glaciation. The high continental elevations due to the uplift gave it a significant head start over other polar regions.

“Before 50 million years ago, most of the Gamburtsev Mountains lay below 1.5 km in elevation. But by 34 million years ago, almost half of the range stood above 2 km—high enough for snow and ice to persist year-round until it had built up into an ice cap.”

“Air temperatures can drop by up to 1°C for every 100 meters (328 feet) of altitude gained."

     The authors note that as the ice sheet expanded, it reflected more sunlight back into space and created a feedback known as the ice-albedo effect that resulted in further cooling of Earth’s temperatures by about 1 degree C, not enough to initiate glaciation in the Northern Hemisphere. Later, another feedback became more prominent as the Antarctic region cooled. Colder air holds less water vapor, which can envelop the Earth like an insulating blanket. As the air dried, this insulating effect weakened, allowing temperatures to fall further.

"Together, these feedbacks allowed the Antarctic ice sheet to spread from the mountains across the continent, eventually reaching the coast," added Goodwin.

"Our findings reveal that the Earth's interior preconditions landscapes to glaciation, determining when and where major climate transitions like the glaciation of Antarctica become possible," explained Gernon. "That's incredibly important for understanding Earth's ancient ice ages as well as future tipping points in the climate system."

     According to the paper:

“We hypothesize that geodynamic surface uplift, causally related to continental breakup between Africa and Antarctica more than 100 Myr earlier, preconditioned Antarctica for ice sheet expansion. We tested this by combining landscape evolution models with energy balance and ice sheet models to isolate the climatic impact of evolving topography over multimillion-year timescales. We assessed elevation thresholds for ice sheet growth under a range of plausible global temperature states and evaluated how different uplift scenarios may have influenced global mean surface temperatures.”

“Renewed uplift (rejuvenation) of the Gamburtsevs in the Eocene resulted in a fluvially incised mountain landscape, later locally overprinted by alpine-style glaciation. Uplift in the ~15 Myr preceding the EOT greatly expanded the area above the permanent snow line. Together, our ice sheet and energy balance models indicate that dynamic uplift controlled the timing of ice cap expansion, pushing elevations above the threshold for ice sheet growth at ~45 Ma.”

     Accelerated uplift during the last 15 million years of the Eocene set the stage for ice sheet expansion.

    

 

 

References:

 

Scientists uncover why Antarctica became engulfed by ice millions of years before the Arctic. Science X staff. Phys.org. July 2, 2026. Scientists uncover why Antarctica became engulfed by ice millions of years before the Arctic

Continental breakup–driven uplift instigated East Antarctic Ice Sheet formation. Thomas M. Gernon, Thea K. Hincks, Philip Goodwin, Guy J. G. Paxman, Sascha Brune, Eelco J. Rohling, Derek Keir, and Jean Braun. Science. 2 Jul 2026. Vol 393, Issue 6806. Continental breakup–driven uplift instigated East Antarctic Ice Sheet formation | Science