February 24, 2009

Antarctic Alps

File this (via the UK Guardian) under "way cool":
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.

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."
Meanwhile now they tell us that they know very little about how about how these ice sheets formed. Is it any surprise that we're just as confounded when they disappear?

Photo courtesy NOAA

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