You’re looking at the most detailed map yet of the Antarctic landmass. Stripped clean of all its ice, the polar continent exhibits a number of interesting features, including vast mountain ranges, sprawling plains — and the lowest gorges and valleys that have ever been seen on Earth.
The map, which was compiled by scientists working at the British Antarctic Survey, was pieced together by a system called Bedmap2. It was a technique that pulled information from satellite imagery, radio echoes of ice thickness, seismic techniques, and cartographic data.
Among the more surprising discoveries was a new deepest point. The area immediately under Byrd Glacier in Victoria Land is 1.7 miles (2.8 kilometers) below sea level. That’s 400 meters deeper than the previously identified deepest point.
BAS has put together a quick synopsis of Antarctica's more interesting features:
- The volume of ice in Antarctica is 4.6% greater than previously thought
- The mean bed depth of Antarctica, at 95 metres, is 60 m lower than estimated
- The volume of ice that is grounded with a bed below sea level is 23% greater than originally thought meaning there is a larger volume of ice that is susceptible to rapid melting. The ice that rests just below sea level is vulnerable to warming from ocean currents
- The total potential contribution to global sea level rise from Antarctica is 58 metres, similar to previous estimates but a much more accurate measurement
LiveScience describes the landscape and its geological history:
Like Alaska's mighty Yukon, a broad river once flowed across Antarctica, following a gentle valley shaped by tectonic forces at a time before the continent became encased in ice. Understanding what happened when rivers of ice later filled the valley could solve certain climate and geologic puzzles about the southernmost continent.
The valley is Lambert Graben in East Antarctica, now home to the world's largest glacier. Trapped beneath the ice, the graben (which is German for ditch or trench) is a stunning, deep gorge. But before Antarctica's deep freeze 34 million years ago, the valley was relatively flat and filled by a lazy river, leaving a riddle for geologists to decode: How did Lambert Graben get so steep, and when was it carved?
The key to Lambert Graben's history was found in layers of sediments just offshore, in Prydz Bay. In a new study, Stuart Thomson, a geologist at the University of Arizona (UA) in Tucson, looked into the past by decoding sands deposited by the river, and the messy piles left behind by the glacier. The river sands are topped with a thick layer of coarser sediment that signals the onset of glacial erosion in the valley, the researchers found. The erosion rate more
"The only way that could happen is from glaciers," he said. "They started grinding and forming deep valleys."