'Frozen in time' landscape discovered under Antarctic ice

ANTARCTICA

Scientists revealed on Oct. 24 that they had discovered a vast, hidden landscape of hills and valleys carved by ancient rivers that has been "frozen in time" under the Antarctic ice for millions of years.

This landscape, which is bigger than Belgium, has remained untouched for potentially more than 34 million years, but human-driven global warming could threaten to expose it, the British and American researchers warned.

"It is an undiscovered landscape - no one's laid eyes on it," Stewart Jamieson, a glaciologist at the UK's Durham University and the lead author of the study, told AFP.

"What is exciting is that it's been hiding there in plain sight," Jamieson added, emphasizing that the researchers had not used new data, only a new approach.

The land underneath the East Antarctic Ice Sheet is less well known than the surface of Mars, Jamieson said.

The main way to "see" beneath it is for a plane overhead to send radio waves into the ice and analyze the echoes, a technique called radio-echo sounding.

But doing this across the continent - Antarctica is bigger than Europe - would pose a huge challenge. So the researchers used existing satellite images of the surface to "trace out the valleys and ridges" more than two kilometers below, Jamieson said.

The undulating ice surface is a "ghost image" that drapes gently over these spikier features, he added.

When combined with radio-echo sounding data, an image emerged of a river-carved landscape of plunging valleys and sharply peaked hills similar to some currently on the Earth's surface.

It was like looking out the window of a long-haul flight and seeing a mountainous region below, Jamieson said, comparing the landscape to the Snowdonia area of northern Wales.

The area, stretching across 32,000 square kilometers, was once home to trees, forests and probably animals. But then the ice came along and it was "frozen in time", Jamieson said.

Exactly when sunshine last touched this hidden world is difficult to determine, but the researchers are confident it has been at least 14 million years. Jamieson said his "hunch" is that it was last exposed more than 34 million years ago, when Antarctica first froze over.