Giant Subglacial Trench Deeper Than the Grand Canyon Discovered in Antarctica

What lies beneath the Antarctic Ice has long remained a mystery. Now, scientists have uncovered a massive, ancient subglacial trough that's deeper than the Grand Canyon. The discovery reveals a little bit more about the region and its distinct and unusual features.

Finding this subglacial canyon wasn't easy, though. The researchers charted the Ellsworth Subglacial Highlands, an ancient mountain range buried beneath several kilometers of Antarctic Ice. In order to do so, they combined data from satellites and ice-penetrating radars towed behind snowmobiles and onboard small aircraft. In all, they spent three seasons investigating and mapping the region.

The newly discovered canyon is about three kilometers deep and is more than 300 kilometers long. In addition, it's about 25 kilometers across. In fact, there are places along the canyon where the floor is more than 2,000 meters below sea level.

The discovery of the canyon was actually serendipitous. The researchers acquired ice penetrating radar data from both ends of the hidden valley, but had no information to tell them what was in between. Satellite data was then used to fill the gap; despite being covered b ice, the valley was so vast it could be seen from space.

So how did this deep valley form? Both the mountain range and valley were probably carved millions of years ago by a small icefield similar to those of the present-day Antarctic Peninsula. The new findings show where and how the West Antarctic Ice Sheet originated and grew. More importantly, it provides clues about the size and shape of the ice sheet in West Antarctica in a warmer global climate.

"To me, this just goes to demonstrate how little we still know about the surface of our own planet," said Neil Ross, one of the researchers, in a news release. "The discovery and exploration of hidden, previously-unknown landscapes is still possible and incredibly exciting, even now."

The findings are published in the journal Geological Society of America Bulletin.