Friday 31 October, 2014

Mystery surrounding Antarctic’s Gamburtsev Subglacial Mountains solved

Published On: Fri, Nov 18th, 2011 | Geology | By BioNews

The Gamburtsev Subglacial Mountains in Antarctica formed as a result of multiple tectonic events, rather than a single event, a new study has claimed.

The discovery made by researchers funded by the National Science Foundation (NSF) may have at last answered a 50 year-old conundrum surrounding the formation of the mountain since their discovery in 1958.

According to the researchers, a remarkably long geological history explains the formation of the mountain range buried beneath the vast East Antarctic Ice Sheet in the least explored frontier on Earth, where the Antarctic Ice Sheet first formed.

Around one billion years ago, before animals and plants evolved on Earth, several continents collided, pushing up a mountain range and forming a thick crustal root.

While the mountain range eroded away, the root was preserved, and over time, events rejuvenated the roots and rifting allowed more uplift to reform the mountains and the ice sheet preserved them.

Around 250-100 million years ago–when dinosaurs walked the Earth–rifting paved the way for the supercontinent Gondwana to break apart, which included Antarctica, causing the old crustal root to warm.

This rejuvenated crustal root, together with the East Antarctic Rift forced the land upwards again reforming the mountains. Rivers and glaciers carved deep valleys and this helped uplift the peaks to create the spectacular landscape of the Gamburtsevs, which resemble the European Alps.

The East Antarctic Ice Sheet, which formed 34 million years ago and covers 10 million square kilometers of our planet, an area the size of Canada, protected the mountains from erosion.

NSF led the multi-national effort and was the lead U.S. agency for the IPY, a concentrated deployment by scientists of 60 nations to the Polar Regions.

During IPY, a seven-nation team made up the Antarctica’s Gamburstev Province (AGAP) project, consisting of scientists from Australia, Canada, China, Germany, Japan, the United Kingdom and the United States.

“Resolving the contradiction of the Gamburtsev high elevation and youthful Alpine topography but location on the East Antarctic craton by piecing together the billion year history of the region was exciting and challenging,” Carol Finn, co-author on the paper, said.

“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. The youthful look of any mountain range may mask a hidden past,” he added.

The study has been published in the journal Nature.

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