What lies below the Antarctica ice sheet? Rocky mountains, canyons and...

Antarctica is hiding mountains and canyons under its ice sheet, a new map of the landscape underneath has revealed. Assembled by a team of international scientists led by the British Antarctic Survey (BAS), it is the most detailed map of a region that lies below the ice of Antarctica.

Bedmap3 has been created using survey data spanning a whopping six decades, all acquired not just by high-tech instruments like satellites, but also by dog-drawn sledges.

The map has been published in the journal Scientific Data.

What the map shows is Antarctica without its 27 million cubic km of ice, revealing the location of its tallest mountains and even some of its deepest canyons. The map of Antarctica also changes the previous belief of where the thickest overlying ice is on the continent. As per previous data, this site was Astrolabe Basin, in Adélie Land. 

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However, as per new calculations, the thickest overlying ice is in an unnamed canyon at 76.052°S, 118.378°E in Wilkes Land. The ice here is 4,757 metres thick, or to put it in context, more than 15 times the height of the Shard, the UK's tallest skyscraper.

Scientists say the new map will help them learn more about Antarctica and how it might change owing to a warming climate since the scientists can now study interactions between the ice sheet and the bed.

Dr. Hamish Pritchard, a glaciologist at BAS and lead author on the study says it is like "pouring syrup over a rock cake—all the lumps, all the bumps, will determine where the syrup goes and how fast."

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He says, it is the same with Antarctica also, "some ridges will hold up the flowing ice; the hollows and smooth bits are where that ice could accelerate."

This is the third such map of Antarctica, with the first one coming in 2001. Bedmap3 is more refined than the previous two maps as it includes more than double the number of previous data points (82 million), rendered on a 500 m grid spacing.

More information has been gathered about East Antarctica including around the South Pole, along the Antarctic Peninsula and West Antarctic coastlines, and in the Transantarctic Mountains. The map also shows a better view of the deep valleys and huge rocky mountains cutting through the ice. 

It also offers a better view of the height and shape of the ice sheet and the thickness of the floating ice shelves. The places where ice at the edge of the continent meets the ocean and begins to float are also well represented.

Peter Fretwell, mapping specialist and co-author at BAS, says, "In general, it's become clear the Antarctic Ice Sheet is thicker than we originally realized and has a larger volume of ice that is grounded on a rock bed sitting below sea level."