The birth of the Gamburtsev Subglacial Mountains buried beneath the vast East Antarctic Ice Sheet — a puzzle mystifying scientists since their discovery in 1958 — is finally solved, according to press releases from NSF and British Antarctic Survey.
International team of scientists explored the Gamburtsev Subglacial Mountains during the International Polar Year 2007–09 by using two twin-engine aircraft equipped with ice penetrating radars, gravity meters and magnetometers.
By analyzing the new data, the researchers describe the extraordinary processes — which took place over the last billion years — that created and preserved a root beneath the mountains and the East Antarctic rift system — a 3,000km long fracture in the earth’s surface that extends from East Antarctica across the ocean to India. This week’s journal Nature reports the findings.
One billion years ago, before animals and plants evolved on Earth, several continents collided, crushing the oldest rocks of the mountain range together. This event formed a thick crustal root extending deep beneath the mountain range. Over time these ancient mountains were eroded but the cold dense root was left behind.
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.
“Understanding the origin of the Gamburtsevs was a primary goal of our International Polar Year expedition. 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. The rift system was also found to contain the largest subglacial lakes in Antarctica”, said lead author Dr. Fausto Ferraccioli from British Antarctic Survey.
“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,” added Carol Finn of the U.S. Geological Survey, a co-author on the paper.
These discoveries in central East Antarctica have significant implications for understanding mountain building and ice sheet evolution within continental interiors.
Source link: https://www.sci.news/othersciences/geophysics/antarcticas-mountains-mystery-solved.html