How did a giant mountain range form beneath a mile of Antarctic ice?

The Gamburtsev Mountains are over 750 miles long and nearly 9,000 feet tall, making them roughly the same size as the Alps. But nobody has ever even seen these mountains, because they're located deep beneath the Antarctic ice sheet.

First discovered in 1958, the Gamburtsev Mountains might literally be the biggest mystery on the planet. How could a mountain range of such immense size be buried so far beneath anywhere between 2000 feet and a mile of snow and ice? It's not an easy question to answer - as Columbia geophysicist Robin Bell points out, we have plenty of rock samples from the Moon and other far distant objects, and yet none from an Alps-sized mountain range on our own planet.

As such, scientists have to rely on more indirect methods to piece together the range's origins. An international team used a mix of ice-penetrating radar, gravity meters, and magnetometers to peer through the ice and figure out the exact contours of the peaks and valleys that make up the Gamburtsevs. From this data, they've been able to piece together a likely history of Earth's only literally unclimbable mountains.

How did a giant mountain range form beneath a mile of Antarctic ice?

According to their research, the mountains first formed a billion years ago during a massive collisions of continents. This causes the rocks that make up the Gamburtsev Mountains to smash together, but more importantly they created a thick root deep in the crust below the mountain range. Over the ensuing hundreds of millions of years, these first Gamburtsevs were eroded away, leaving only the crustal root.

It was from that root that the new Gamburtsevs would form somewhere between 250 and 100 million years ago, as the southern supercontinent Gondwanaland broke part. This process warmed up the root, and this in turn pushed land back upwards, full of rivers and glaciers that over time carved a spectacular mountain range. The East Antarctic Ice Sheet formed about 34 million years ago and completely covered the Gamburtsevs, protecting from further erosion but leaving them completely hidden from the rest of the world.

Robin Bell explains this remarkable process:

"It has been almost a billion years since the Gamburtsev first formed. 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. 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 team next hopes to drill down to the mountains to retrieve the first actual samples from the mountains. From there, well...perhaps I spoke too soon when I declared these mountains unclimbable. If nothing else, an expedition down there would make for one hell of a movie, even if it's not possible to actually do it here in reality.

Via Nature. Top image of above-ground Antarctic mountains by eliduke on Flickr. Second image by Zina Deretsky/NSF.