Antarctic 'Alps' mapped

'Ghost peaks' mapped under ice

By Jonathan Amos Science reporter, BBC News

The scale of the AGAP project required international co-operation

Scientists have completed their mission to map one of the most extraordinary mountain ranges on Earth.

The Gamburtsevs are a set of peaks equal in size to the European Alps, but they are hidden deep under the ice in the middle of the Antarctic continent.

The survey data gathered by the multi-national team working in harsh, sub-zero temperatures will help resolve the mystery of why the range exists at all.

Their presence, when first discovered in the 1950s, was totally unexpected.

Scientists thought the interior of the continent would be relatively flat.

Modern-day remote-sensing technology reveals quite the opposite - a very jagged landscape.

The data will be analysed by researchers in the coming months

"We can confirm they are there; we've seen them under the ice," said Dr Fausto Ferraccioli from the British Antarctic Survey.

"Not only are they similar in dimension to the European Alps, but they are also similar in aspect: we see very sharp peaks and valleys which are remarkably similar to the Alps themselves," he told BBC News.

"It all adds to the mystery - from the tectonic perspective of how these mountains were created; and from the glacial history perspective of how the East Antarctic ice sheet was formed and didn't erode these peaks."

The AGAP (Antarctica's Gamburtsev Province) project comprised scientists, engineers, pilots and support staff from the UK, the US, Germany, Australia, China and Japan.

They established two field camps deep in the Antarctic interior.

Aircraft swept back and forth across the ice, mapping the shape of the sub-glacial mountains using ice-penetrating radar.

Other instruments measured the local gravitational and magnetic fields.

EXPLORING THE SUBGLACIAL GAMBURTSEV MOUNTAINS 1. Aircraft used radar to detect ice thickness and layering, and mapped the shape of the deeply buried bedrock 2. The planes also conducted gravity and magnetic surveys to glean more information about the mountains' structure 3. By listening to seismic waves passing through the range, scientists could probe rock properties deep in the Earth

Information on the deeper structure of the Gamburtsevs was gleaned from a network of seismometers that listened to earthquake signals passing through the rock from the other side of the globe.

"The temperatures at our camps hovered around -30C, but three kilometres beneath us at the bottom of the ice sheet we saw liquid water in the valleys," explained AGAP US co-leader Dr Robin Bell, of the Lamont-Doherty Earth Observatory at Columbia University, New York.

AGAP was a flagship expedition for International Polar Year (IPY), a concerted effort by the science community to better understand both the Antarctic and the Arctic.