A team of researchers surveying Antarctica have discovered what they believe to be a canyon that's as deep as the Grand Canyon, but much longer. According to the study, published this month in the journal Geology, what could be the world's largest canyon may cut across nearly 700 miles of East Antarctica, reaching depths of over half a mile. The Grand Canyon is less than half that length, at around 277 miles long.
In 2013, scientists discovered a massive canyon under the Greenland ice sheet that already overshadowed the Grand Canyon, but this new Antarctic canyon would dwarf both formations. Greenland's canyon is estimated to be at least 460 miles long and also around half a mile deep in some places. There are also a number of other canyons around the world not covered in ice that rival the size and depth of the Grand Canyon.
The only obstacle in the way of knowing for certain whether the Antarctic canyon is as big as it initially appears is the Antarctic ice sheet. Researchers are already addressing this uncertainty by taking airborne radio-echo sounding measurements that can confirm the size and extent of the canyon and connected lake system. This data should be available by the end of 2016.
This giant chasm truly is located at the end of the earth in an area where the topology is less well-known than that on Mars. Scientists often refer to the region as one of Antarctica's two 'Poles of Ignorance.'
From what the researchers can determine from the satellite imagery and small sections of the canyon for which they have radio-echo sounding data, the shape of the landscape beneath the ice sheet appears to have been carved by ancient water. Either this water was there before the ice sheet grew or it could have been created by water flowing under the ice.
According to co-Author Professor Martin Siegert, from the Grantham Institute at Imperial College London in the UK, "discovering a gigantic new chasm that dwarfs the Grand Canyon is a tantalizing prospect" but also one with real-world applications.
Siegart said that the stability of Antarctica is threatened by global warming, and that better understanding the buried landscape will help scientists determine how the ice sheets respond to changes in climate.
The Antarctic Ice Sheet covers nearly 5.4 million square miles, around the area of the contiguous United States and Mexico combined. If the entire Antarctic Ice Sheet melted, sea level would rise by around 200 feet. According to the National Snow and Ice Data Center, while most of Antarctica is yet to see dramatic warming, an area of the region that juts out into warmer waters north of Antarctica has warmed by 4.5 degrees Fahrenheit since 1950.
The findings of the new study also show that the massive canyon may be connected to a heretofore undetected sub-glacial lake that could be nearly 780 square miles in area.
"Our analysis provides the first evidence that a huge canyon and a possible lake are present beneath the ice in Princess Elizabeth Land," said Dr. Stewart Jamieson, a lead researcher on the study from Durham University in the UK, in a statement. "It’s astonishing to think that such large features could have avoided detection for so long."