Antarctica looks empty at first glance, just ice and more ice. Yet new research shows that under about 2 kilometers of the East Antarctic Ice Sheet, there is a surprisingly well-preserved landscape of valleys and ridges that last saw daylight around 34 million years ago.
Scientists say this buried “lost world” was carved by rivers before Antarctica froze and may once have supported forests and wetlands instead of today’s lifeless white plateau. By mapping this hidden terrain and comparing it with ancient sediment records, researchers are piecing together how the continent flipped from green to ice-covered, and what that history can tell us about future sea level rise.
What lies beneath the East Antarctic ice sheet
The East Antarctic Ice Sheet is the largest single mass of ice on Earth, and in places it is more than 2 kilometers thick. Beneath that ice, a team led by glaciologist Stewart Jamieson at Durham University has identified blocks of elevated land cut by deep valleys, stretching across an area roughly the size of Maryland.
These valleys look very much like old river systems, not the scraped, jagged surfaces usually left by moving ice. The landscape appears to have formed when rivers flowed across Antarctica’s high ground before a permanent ice sheet grew at the end of the Eocene period, then remained almost untouched once the ice settled.
A newer study in Nature Geoscience, led by geophysicist Guy Paxman, shows that similar flat or gently sloping surfaces ring about 40 percent of the East Antarctic coastline. Once you correct for the weight of today’s ice, those surfaces line up as a coastal plain that dipped gently toward the ancient ocean, suggesting a broad, low landscape shaped by rivers between about 100 and 34 million years ago.
How scientists uncovered this ancient river world
Researchers did not simply drill a giant hole and stumble onto a buried forest. They started by using radio echo sounding, a technique where aircraft tow radar systems that send pulses through the ice and record echoes from the bedrock below. Small changes in the ice surface, measured by satellites such as RADARSAT, helped confirm where hidden ridges and valleys lie.
Those radar profiles reveal three large blocks of rough highlands separated by deep troughs, plus long stretches of remarkably flat surfaces near the coast. The fact that these shapes remain sharp after tens of millions of years suggests the ice above them has stayed very cold and has moved relatively slowly, so it protected the terrain rather than grinding it away.
So far, the “lost world” has been seen only through ice-penetrating instruments and computer models. Scientists involved in the recent Nature Geoscience work say the logical next step is to drill through the ice in targeted spots and bring up rock and sediment, something hot water drills and specialized coring systems have already achieved at other Antarctic sites such as subglacial lakes and grounding zones.
A greener Antarctica in Earth’s deep past
Why do researchers think this buried landscape was once green rather than bare rock. Evidence from marine sediments around Antarctica shows that, before the ice sheet formed, coastal regions supported temperate or even near tropical rainforests, with pollen and spores from broadleaf trees, conifers and ferns preserved in the mud.
A 2014 paper in Earth and Planetary Science Letters used pollen and plant wax molecules from a core near the Antarctic Peninsula to show that late Eocene forests cooled and dried just before large-scale glaciation took hold around 34 million years ago. Those results suggest a shift from lush, warm rainforests to cooler, more open woodland right as ice sheets began to grow.
Put together, the buried valleys under East Antarctica and the offshore sediment records point to a continent that once looked a lot like parts of New Zealand or southern Chile today. Rivers probably wound through low hills covered with dense vegetation, then the climate crossed a threshold where falling carbon dioxide and changing ocean currents allowed ice to spread quickly across that landscape.
Why a buried landscape matters for future sea levels
At first glance, this might sound like ancient trivia. In practical terms, though, the shape of the land beneath the ice acts like plumbing for the ice sheet, steering fast ice streams toward the ocean while leaving other regions almost locked in place. The flat surfaces mapped by Paxman’s team seem to slow ice flow along parts of the East Antarctic margin, while deep troughs funnel ice toward the sea.
That matters because East Antarctica contains enough frozen water to raise global sea levels by more than 50 meters if it ever melted completely, and parts of its low lying coastal basins are already considered vulnerable in a warming world.
Knowing where ancient river plains and valleys sit beneath the ice helps modelers refine how quickly different sectors might respond as the ocean and atmosphere heat up.
For people far from the ice, the connection is simple. Better maps of this hidden “lost world” feed directly into projections that shape coastal planning, insurance costs and long-term infrastructure decisions in cities from Miami to Rotterdam.
The main study has been published in Nature Communications.
Image credits: Durham University / Rod Arnold / British Antarctic Survey
