Wednesday, July 2, 2008

Hidden area beneath Antarctic ice revealed

By Richard Gray, Science Correspondent
Last Updated: 7:01pm BST 21/06/2008

With jagged mountain ranges, plunging valleys and majestic lakes, Antarctica has scenery to rival any beauty spot in the world – except that no-one has ever seen the continent's hidden landscape.
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For more than 25 million years, the fifth biggest continent on the planet has remained locked under a massive ice sheet that has concealed its secrets through out the whole of human history.

Entire mountain ranges, volcanoes, rivers, waterfalls and even new forms of life are waiting to be discovered beneath the ice.

Now scientists are hoping to reveal the secrets of this hidden Antarctic landscape for the first time with one of the biggest exploration projects undertaken in more than three decades.

Using new technology they aim to peer through the ice, which can be up to three miles thick in places, to create the most complete picture of what the ground beneath is really like.

Robotic submarines will also be sent down through shafts drilled into the ice to search the depths of lakes that have been found under the ice sheets for new forms of bacteria and other small organisms that scientists believe could be thriving there.

Their research promises to reveal more about this lost continent than has ever been known before.

"We know more about the surface of Mars than we do about the land beneath the ice in Antarctica," explained Professor Martin Siegert, one of the leaders behind the exploration projects and head of geosciences at the University of Edinburgh.

"People often forget that there is land beneath all the ice, and it is of fundamental value to us in understanding how the ice flows and the impact it will have on sea level rise."

Only the occasional tip of a rocky mountain peeking through the frozen, inhospitable wastes hints at the mysterious landscape below.

Antarctica has not always been a frozen land, and around 40 million years ago it had a climate that was warmer than the UK is currently.

Ice sheets began to form on the continent 30 million years ago and now it is almost completely covered by a barren ice sheet, where temperatures fall to -89 degrees C.

In places the ice is known to be three miles thick and the intense pressure created has scoured huge valleys and basins out of the rock, so that in some areas the solid ground is more than a mile below sea level.

Together with a British Antarctic Survey project to survey another part of Antarctic, the Edinburgh scientists behind the ICECAP project will use specially equipped aircraft to map 3.8 million square miles, about a third of the continent.

The planes, which will be Basler long range and Twin-Otter short range aircraft, will use high definition radar to penetrate the ice and image the landscape below, while gravity meters and magnetic meters will measure the type of rocks of which the land is made up.

A separate project is also aiming to explore on of the deep water lakes that have been found beneath the antarctic ice.

These subglacial lakes, as they are known, are formed in basins that are carved out by the huge quantities of ice above the land.

The extremely high pressures created by the ice pushing down on the ground can cause the ice at the base of the ice sheets to melt to form lakes and rivers, despite the cold temperatures.

This occurs because water fills a smaller volume when it is a liquid than when it is solid, so when under high pressures the water will become liquid more easily and the heat from the ground can be enough to melt it.

One of the biggest such subglacial lakes, as they are known, discovered so far is Lake Vostok in East Antarctica. It is thought to be more than 150 miles long and 50 miles wide.

Almost nothing is known about these lakes and what they hold, including possible new life forms.

Professor Siegert and his colleagues are now planning to send a robotic submarine into one lake, known as Lake Ellsworth in West Antarctica.

The remote controlled robot will then explore the dark water searching for microscopic life that may have been evolving for millions of years in the harsh conditions.

Dr Fausto Ferraccioli, the aero-geophysics group leader at the British Antarctic Survey, said: "There could be hundreds more of these lakes beneath the ice, and entire mountain ranges waiting to be found."