Truth behind Antarctic 'ghost' mountains revealed - Stuff.co.nz

Researchers have probed the depths under Antarctic ice to reveal a map of the Gamburtsev Mountains. Credit: Zina Deretsky, National Science Foundation, Gamburtsev topography by Abdulhakim Abdi, Lamont-Doherty Earth Observatory of Columbia University

Scientists believe they have uncovered the truth behind an enormous "ghost" mountain range buried below Antarctica.

The Gamburtsevs were first discovered in the 1950s, taking the science world completely by surprise.

Far from the flat and featureless rock expected under the Antarctic ice, a craggy range the size of the European Alps was found in the deep.

Survey data now suggests the mountains first formed more than a billion years ago, a study published in the journal Nature says.

The Gamburtsevs are thought to be the location where the ice sheet we know today began its march across the frozen continent.

Unravelling the mountains' history will therefore inform climate studies, helping scientists understand both past changes on Earth and possible future scenarios.

"Surveying these mountains was an incredible challenge, but we succeeded and it's produced a fascinating story," Dr Fausto Ferraccioli from the British Antarctic Survey (BAS) told BBC News.

Dr Ferraccioli was a principal investigator on the AGAP (Antarctica's Gamburtsev Province) project, completed in 2009.

To map the mountains scientists flew an aircraft back and forth across Antarctica, scanning the Earth with radar. Other instruments recorded the local gravitational and magnetic fields and seismometers were used to probe the ground.

The scientists believe the collision of continents to form the landmass known as "Rodina" first gave life to the range more than a billion years ago.

The impact pushed up the mountains, also creating a dense, cold "root" that sat deep in the Earth's crust.

While the mountains eroded over the course of hundreds of millions of years, only the root remained. And when, 250-100 million years ago, the crust began to pull apart again the root was rejuvenated.

Warmed by the movement, it pushed the land up, re-forming the Gamburtsevs.

Rivers and glaciers formed deep valleys. It was those glaciers, the researchers say, that became the mountain's demise, spreading and entombing them in layer of ice no known as the East Antarctic Ice Sheet.

"This research really solves the mystery of how you can have young-looking mountains in the middle of an old continent," said US principal investigator Dr Robin Bell from the Lamont-Doherty Earth Observatory of Columbia University.

"In this case, the original Gamburtsevs probably completely eroded away only to come back, phoenix-like. They've had two lives," she told BBC News.

Next on the agenda is retrieving rock samples and ice from the mountains, to confirm the model.

Scientists believe the range may have ice more than a million years old - at least 200,000 years older than the most ancient ice currently held.

- Stuff