Origins of Gamburtsev Sublacial Mountains Explained
17.11.2011 - Land & Geology, Antarctic
An international team of scientists from seven nations recently published in Nature their findings regarding the origins of the Gamburtsev Subglacial Mountains, located 3 km beneath the East Antarctic Ice Sheet. How the mountains formed is a mystery that has interested scientists since they were first discovered in 1958 as they are high, located in the middle of an ancient craton, yet have a youthful appearance for mountains.
During the International Polar Year (2007-2008), researchers from the Antarctica’s Gamburtsev Province (AGAP) project flew two twin-engine aircraft equipped with ice penetrating radars, gravity meters and magnetometers over the part of the East Antarctic Ice Sheet where the Gamburtsev Mountains lie. Analyzing the data they gathered, the team was able to describe the geological processes that have taken place over the past billion years to create the East Antarctic Rift System (a 3,000 km fracture extending from Antarctica to India).
One billion years ago, several landmasses collided, pushing the oldest rock of the Gamburtsevs together and forming a thick, crustal root deep beneath the mountains. Later, when the Gondwana Supercontinent (what is now South America, Africa, Antarctica, Australia and the Indian subcontinent) began to break up 250 – 100 million years ago, this caused the old crustal root to warm once again. Together with the East Antarctic Rift, the crustal root pushed the land upwards again, reforming mountains and thus creating the modern Gamburtsevs.
Intricate glacier and river systems carved deep valleys in the Gamburtsevs, giving them a spectacular landscape, resembling that of the Alps. Ever since the Antarctic Ice Sheet formed some 34 million years ago, the Gamburtsevs have been protected from further erosion.
According to the article’s lead author, Dr. Fausto Ferraccioli from the British Antarctic Survey, the key to piecing together the puzzle of their origin was discovering similarities between the East Antarctic and East African Rift Systems. Co-author Carol Finn from the US Geological Survey, these findings have significant implications for understanding mountain formation and ice sheet evolution within continental interiors, as the formation of the Gamburtsevs involved more than one tectonic event.
The next steps will be to retrieve the first rock samples from the Gamburtsevs to find out exactly when the mountain range formed, according to co-author, Dr. Robin Bell of Columbia University’s Lamont-Doherty Earth Observatory.