Alister Doyle, PlanetArk 25 Feb 09;
"Unless we have a basic understanding of how ice sheets work, any sort of predictive model (for rising sea levels) won't match reality"
OSLO - Jagged mountains the size of the Alps have been found entombed in Antarctica's ice, giving new clues about the vast ice sheet that will raise world sea levels if even a fraction of it melts, scientists said on Tuesday.
Using radar and gravity sensors, the experts made the first detailed maps of the Gamburtsev subglacial mountains, originally detected by Russian scientists 50 years ago at the heart of the East Antarctic ice sheet.
"The surprising thing was that not only is this mountain range the size of the Alps, but it looks quite similar to the (European) Alps, with high peaks and valleys," said Fausto Ferraccioli, a geophysicist at the British Antarctic Survey who took part in the research.
He told Reuters that the mountains would probably have been ground down almost flat if the ice sheet had formed slowly. But the presence of jagged peaks might mean the ice formed quickly, burying a landscape under up to 4 km (2.5 miles) of ice.
Ferraccioli said the maps were "the first page of a new book" of understanding how ice sheets behave, which in turn could help predict how the ice will react to global warming.
Antarctica, bigger than the United States, has been swathed in ice for about 35 million years, and contains enough of it to raise world sea levels by about 57 meters (187 feet) if it ever all melted. So even a fractional melt would affect coasts around the globe.
"Unless we have a basic understanding of how ice sheets work, any sort of predictive model won't match reality," Ferraccioli said.
The U.N. panel on climate change says that greenhouse gases, mainly emitted by burning fossil fuels, will bring more heatwaves, floods and droughts, and raise sea levels.
The team of experts from Australia, Britain, Canada, China, Germany, Japan and the United States also found water below the ice, using survey aircraft that flew 120,000 km (75,000 miles).
"The temperatures at our camps hovered around minus 30 Celsius (minus 22 Fahrenheit), but 3 km (2 miles) beneath us at the bottom of the ice sheet we saw liquid water in the valleys," Robin Bell, of the Lamont-Doherty Earth Observatory at Columbia University, said in a statement.
Many sub-glacial lakes have been found in Antarctica in recent years.
Geologists say that mountain ranges such as the Alps or the Himalayas form in collisions between continents. The last time Antarctica was exposed to such forces was 500 million years ago.
"The mystery here is that the Alps are only 50 to 60 million years old, while here we have a mountain range that may perhaps be as old as 500 million years," Ferraccioli said.
(Editing by Kevin Liffey)
Scientists discover Alps-scale mountain range under Antarctic ice
Scientists have discovered a massive mountain range, the size of the Alps and named the Gamburtsev range, two miles under the world's largest ice sheet in the Antarctic.
Louise Gray, The Telegraph 24 Feb 09;
Researchers flew aircraft 75,000 miles over six weeks braving average temperatures of -30 Celsius mapping the ancient Gamburtsev range.
They predicted a flat plateaux but instead found a range similar in height and shape to the Alps - with massive peaks as high as Mount Blanc and deep valleys.
Water, turned to liquid due to the pressure of East Antarctic Ice Sheet above, could be seen in rivers and lakes nestled in valleys.
One lake, named Vostok, was an incredible 187 mile (300km) long making it similar in size to North American Great Lake, Lake Ontario.
Scientists hope the findings will aid predictions about the effects of climate change on ice sheets and challenge long-held views that the ice sheet formed over millions of years.
The new research suggests they formed in a fraction of the time and the area could have been ice free at some points in history.
This means any rapid fluctuation in global temperature could have a much faster effect on the formation of ice sheets than previously thought.
The research was conducted by the Antarctica's Gamburstev Province (AGAP) - a team of scientists, engineers, pilots and support staff from seven nations.
They used state of the art radar, aeromagnetic and gravity sensors to map 386,000sq miles (1,000,000sq km) of the Gamburtsev range 4km under the East Antarctic Ice Sheet.
Geophysicist Dr Fausto Ferraccioli of British Antarctic Survey led the UK science effort.
He said: "We now know that not only are the mountains the size of the European Alps but they also have similar peaks and valleys.
"And this adds even more mystery about how the vast East Antarctic Ice Sheet formed.
"If the ice sheet grew slowly then we would expect to see the mountains eroded into a plateau shape. But the evidence now suggests it formed quickly.
"Our big challenge now is to dive into the data to get a better understanding of what happened. Our findings are like the the first page of a big book."
Mountain range as large as Alps found under Antarctic ice
Subglacial mountains mapped by scientists 2.5 miles under ice
Alok Jha, guardian.co.uk 24 Feb 09;
A mountain range as large as the European Alps is hidden under 2.5 miles of ice in the east of Antarctica, scientists have revealed. The range includes peaks up to 3,000m above sea level and raises questions over how the massive ice sheets on the continent formed.
The subglacial mountains were first detected by Russian researchers more than 50 years ago and are named after a Soviet geophysicist, Grigoriy Gamburtsev. But, despite a small survey carried out in the 1970s, the size and shape of the Gamburtsev mountain range has remained a mystery.
"When we went out to the ice, we knew there was a potentially elevated region there, but we had no idea what it looked like," said Fausto Ferraccioli, a geophysicist at the British Antarctic Survey who led the UK team within the international mapping project. "We now see that this mountain-range is the size of the Alps, but it looks like them too — it has all these fresh-looking peaks and valleys."
The seven-nation research team that produced the map worked for weeks in the harsh conditions around Dome A, the highest point on the Antarctic ice sheet. The average temperature was a chilling -30C. To examine the buried mountains, they flew aeroplanes fitted with radar, magnetic and gravity sensors over the ice, with the measurements allowing them to "see" the rock beneath.
Researchers constructed a map that revealed a mountain range at least 800km long and up to 400km wide, covering an area the same size as the Euopean Alps, at more than 200,000 square kilometres. Their survey also showed peaks of 3,000m above sea level and valleys down to 1,000m below sea level. The highest peak in the Alps, Mont Blanc, rises more than 4,800m above sea level but the valleys in this area are typically just 500m deep.
This vast range between the peaks and valleys surprised the scientists — such high mountains, which are normally the result of collisions between tectonic plates, should not exist in the centre of an ancient continent. "We're in the middle of an ancient pre-Cambrian craton, so we shouldn't have mountains there at all," said Ferraccioli.
The new maps also raise questions about how the ice sheets formed. The Gamburtsev mountains are thought to be the nucleus around which the vast 10m-square-kilometre East Antarctic ice sheet, the biggest mass of ice in the world, formed. If the ice grew slowly, the scientists would have expected to see a plateau under the sheet, with the moving ice and water having eroded the peaks of the mountains.
"But the presence of peaks and valleys could suggest that the ice sheet formed quickly – we just don't know. Our big challenge now is to dive into the data to get a better understanding of what happened."
Robin Bell, of the Lamont-Doherty Earth Observatory at Columbia University, highlighted another surprise: "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. The radar [data] let us know that it was much warmer at the base of the ice sheet."
Ferraccioli said the new map, completed as part of the International Polar Year, was just the start of their understanding of the Gamburtsev mountains. "I like to compare this to the first page of a new book — a huge new dataset which will provide us with an understanding of the mountains and the origin of the Antarctic ice sheet." The survey planes flew a criss-cross path which charted the area with 20 times more detail than previous maps of the area. The research team plans to release more data about the mountain range, including the maps of another 400km of mountains.
The next steps include studying the different layers of ice in the sheet, to work out where they could drill to find the oldest ice. Such ice cores can provide detailed histories of past climate change on Earth and indicated how the planet will respond to greater concentrations of CO2 in its atmosphere. Scientists will also refine the magnetic and gravitational measurements to reveal further details of the submerged mountains.
