Scientists unearth origins of Antarctic subglacial mountain range
The mystery behind the Gamburtsev Mountain Range in eastern Antarctica has piqued the interest of scientists since 1958. Questions about how this range emerged and impacted the spread of glaciers across the continent millions of years ago resulted in no answers... until now. A team of scientists from Europe and the United States has discovered the origins and evolution of this subglacial mountain chain. The findings are published in the journal Nature. From 2008 to 2009, scientists from Germany, the United Kingdom and United States surveyed the interior of Antarctica by air, using ice-penetrating radar, gravity metres and magnetometers to identify the peaks and valleys hidden below the ice. The researchers point out that continents collided a billion years ago, smashing together the oldest rocks that experts thought to be the Gamburtsev mountains. This collision generated a thick crustal root deep beneath the range. While these prehistoric mountains eroded with time, the cold dense root did not move. The supercontinent Gondwana, which Antarctica was a part of, split sometime between 250 and 100 million years ago. This action resulted in the warming of the crustal root and the East Antarctic Rift pushed land upwards again, changing the mountains. They say rivers and glaciers generated deep valleys and raised peaks to form a landscape that is similar to the Alps in Europe. Created 34 million years ago, the 10 million square kilometres East Antarctic Ice Sheet is about as big as Canada. 'It has been almost a billion years since the Gamburtsev first formed,' explains Robin Bell, a geophysicist at Columbia University's Lamont-Doherty Earth Observatory in the United States, and one of the authors of the study. 'This work shows that very old mountains can rise again, like a Phoenix from the ashes. The Gamburtsevs rose from the long eroded East Antarctic craton.' Commenting on the results, co-author Carol Finn from the U.S. Geological Survey says: 'We are accustomed to thinking that mountain building relates to a single tectonic event, rather than sequences of events. The lesson we learned about multiple events forming the Gamburtsevs may inform studies of the history of other mountain belts.' Lead author Fausto Ferraccioli from the British Antarctic Survey (BAS) says the East Antarctic rift system is the piece that helped the team put the puzzle together. 'It was fascinating to find that the East Antarctic rift system resembles one of the geological wonders of the world - the East African rift system - and that it provides the missing piece of the puzzle that helps explain the Gamburtsev Subglacial Mountains,' Dr Ferraccioli says. 'The rift system was also found to contain the largest subglacial lakes in Antarctica.' Next on the agenda is to drill through the ice and collect rock samples for the first time ever. 'Amazingly, we have samples of the moon but none of the Gamburtsevs,' Dr Bell comments. 'With these rock samples we will be able to constrain when this ancient piece of crust was rejuvenated and grew to a magnificent mountain range.'For more information, please visit:British Antarctic Survey (BAS):http://www.antarctica.ac.uk/Nature:http://www.nature.com/
Countries
Germany, United Kingdom