A detailed map of hidden landscapes beneath Antarctica's ice sheet reveals what really sits beneath the colossal frozen block.

The sheet, which covers an area of almost 14 million km², is the largest single mass of ice on Earth.

Scientists know less about the landscape hidden beneath than they do about the surface of Mars or Venus, as making observations through ice is difficult.

Now, they have combined a new mapping technique with satellite data to provide the most detailed view to date.

It reveals previously unknown features including thousands of subglacial hills and valleys, mountain ranges and deep canyons.

The team said their findings could provide crucial insight into the behaviour of Antarctica's ice sheet, which is retreating and thinning due to warming oceans and air.

Co–author Professor Robert Bingham from the University of Edinburgh's School of GeoSciences, said: 'Over millions of years Antarctica's ice sheet has sculpted a landscape consisting variously of flat plains, dissected plateaus and sharp mountains, all hidden under the present miles–thick ice cover.

'With this technique we are able to observe for the first time the relative distributions of these highly variable landscapes over the whole continent.'

For their study an international team, led by researchers from the University of Edinburgh, used a mapping technique called Ice Flow Perturbation Analysis (IFPA).

This identifies characteristic shapes in the glacial surface generated by the ice flowing over hills and valleys.

They combined IFPA data with the latest satellite observations to reveal the landscape across the whole continent, including previously unchartered regions.

Previous research has shown that rough areas of subglacial land – such as jagged hillsides and sharp mountain ridges – can slow the retreat of Antarctica's glacial sheet by providing frictional resistance against the ice flowing towards the sea.

The latest map serves as an important guide to inform scientists where future surveys should be focused.

It will also help develop more accurate projections of where and how much sea levels could rise in the future, the team says.

'Because making scientific observations through ice is difficult, we know less about the landscape hidden beneath Antarctica than we do about the surface of Mars or Venus,' lead author Dr Helen Ockenden said.

'So it's really exciting that this new method allows us to use satellite measurements of the ice surface to fill all of the gaps in our maps, revealing new details about mountain ranges, canyons and geological boundaries.'

Mathieu Morlighem from Dartmouth College, US, said: 'Understanding the landscape beneath Antarctica is really important for ice–sheet models.

'In particular, rougher areas with more hills can really slow down the retreat of the ice sheet, and so this new map will help our models to produce better projections of where and how much sea levels will rise in the future.'

Co–author Professor Andrew Curtis said the method they used to project ice surface information down from satellites 'provides a completely new way to see through ice sheets'.

'Over several years we have proven that it works well in detailed tests and this application across all of Antarctica demonstrates its power,' he added.

The findings were published in the journal Science.