Rivers not ice carved Antarctic landscape

Picture: Stefan Christmann/BBC NHU/PA Wire
Picture: Stefan Christmann/BBC NHU/PA Wire
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The mountainous landscape lurking under the ice sheet of Antarctica was shaped by rivers during a warmer era in the earth’s history, according to Scottish researchers.

The findings are contrary to previously held beliefs that the continent’s rugged geography was carved out by glaciers.

Academics from the University of Edinburgh and Durham University studied the ground beneath the Antarctic ice sheet and compared it to other southern continents to reconstruct how the landscape would have looked before it was frozen over.

They have concluded that the mountains and valleys of Antarctica were formed millions of years ago, after the landmass separated from what are now Australia, India and Africa, but before it was inundated by ice.

They believe this improved knowledge of how Antarctica’s landscape evolved could be vital in understanding how the ice sheet might react as the planet continues to heat up due to climate change.

“It is remarkable to stand on the slopes of a mountain in South Africa and realise that their exact equivalents lie preserved in ice in Antarctica,” said study leader Professor David Sugden, from the University of Edinburgh’s School of Geosciences.

“The pre-glacial landscape of Antarctica is less well known than the surface of the moon and Mars, and yet it plays a part in how the continent’s ice sheet responds to global warming.

“Learning how it has evolved will help us to better forecast future changes.”

Co-researcher Dr Stewart Jamieson, from the geography department at Durham, added: “The research is an integral part of an effort by the scientific committee on Antarctic research to try to understand how the Antarctic ice sheet might respond to climates that are warmer than present.”

The study shows West Antarctica has a similar landscape and evolved in a similar way to regions such as southern Africa, Australia and Madagascar.

Characteristics such as river valleys, plains, mountain escarpments and basins are the same.

Antarctica was formed after the break-up of the ancient supercontinent Gondwana, which incorporated about half the global landmass.

The process, which shaped lands of the southern hemisphere, began 160 to 180 million years ago.

The formation of ice sheets, which are up to 4km thick in places, in Antarctica began around 34 million years ago.

Knowledge of the pre-glacial landscape helps pinpoint where glaciers first formed.

It also helps determine the nature and stability of the ice sheet bed, which is useful for predicting future changes.

The research was funded by the Natural Environmental Research Council.