What Lies Beneath the Antarctic Ice Sheet?

The Antarctic ice sheet that for centuries hid a massive canyon has slowly been releasing even more secrets about what lies beneath all that ice. For the past few years, researchers have been studying the area beneath the ice, one of the largest unsurveyed land surfaces on Earth. Most recently, a team of glaciologists from the University of California, Irvine, have released a detailed topography map of the area.

The map, part of the BedMachine project, and the related findings were published in the journal Nature Geoscience. Researchers say the study will help reveal the regions of the continent that will likely be most vulnerable to climate warming.

"There were lots of surprises around the continent, especially in regions that had not been previously mapped in great detail with radar," lead author Mathieu Morlighem, UCI associate professor of Earth system science, said in a statement. "Ultimately, BedMachine Antarctica presents a mixed picture: Ice streams in some areas are relatively well-protected by their underlying ground features, while others on retrograde beds are shown to be more at risk from potential marine ice sheet instability."

Some of the most interesting results from the project, according to the university's release, are the discovery of "stabilizing ridges that protect the ice flowing across the Transantarctic Mountains; a bed geometry that increases the risk of rapid ice retreat in the Thwaites and Pine Island glaciers sector of West Antarctica; a bed under the Recovery and Support Force glaciers that is hundreds of meters deeper than previously thought, making those ice sheets more susceptible to retreat; and the world's deepest land canyon below Denman Glacier in East Antarctica."

The map was created using ice thickness data from 19 research institutes from as far back as 1967, as well as ice shelf bathymetry (depth) measurements from NASA, and seismic information.

Hiding the world's largest canyon

Several years ago, geologists studying satellite imagery of the remote Princess Elizabeth Land in East Antarctica discovered evidence of a massive subglacial canyon system buried beneath the ice.

Tipped off by the physical hints, the team of researchers utilized radio-echo sounding to pull back the white curtain and peer through the ice. What they found was an absolute monstrosity of geology, a canyon system believed to be more than 685 miles long and as much as 0.6 mile deep. In some places, the measurements failed simply because they were too deep to be recorded. And there's more:

"Linked to the canyons, a large subglacial lake may exist that may be the last remaining large (more then 62 miles in length) subglacial lake to be discovered in Antarctica," the authors wrote in a paper published in Geology. It's estimated that this subglacial lake alone may cover as much as 480 square miles.

The geologists believe the canyon system was likely carved out by water. Because it's so ancient, however, it's not clear if it formed before or after it was entombed in ice.

"Discovering a gigantic new chasm that dwarfs the Grand Canyon is a tantalizing prospect," study co-author professor Martin Siegert from the Grantham Institute at Imperial College London told IANS. "Our international collaboration of U.S., U.K., Indian, Australian and Chinese scientists are pushing back the frontiers of discovery on Antarctica like nowhere else on Earth."