The team, made up of scientists from the USA, UK and Australia, used ice-penetrating radar to create the first high-resolution topographic map of the region. ‘We knew almost nothing about what was going on, or could go on, under this part of the ice sheet, and now we’ve opened it up and made it real,’ said Duncan Young of the University of Texas at Austin, the study’s lead author.

The resulting map revealed vast channels cut through mountain ranges by ancient glaciers as the East Antarctic ice sheet advanced and retreated between 34 and 14 million years ago. The data will help to improve models of the future behaviour of the ice sheet and its potential impact on global sea levels.

‘We chose to focus on the Aurora Subglacial Basin because it may represent the weak underbelly of the East Antarctic Ice Sheet, the largest remaining body of ice and potential source of sea-level rise on Earth,’ said Donald Blankenship, one of the study’s co-authors.

The basin lies several kilometres below sea level, and there are fears that seawater could penetrate beneath the ice, causing portions of the ice sheet to collapse and float away. Indeed, the current study demonstrated that the ice sheet has been significantly smaller in the past.

July 2011