Antarctic rocks clue to global warming

20 February 2003

Rock samples collected by scientists in Antarctica will lead to a greater understanding of the consequences of sustained global warming.

The Australian Antarctic Division's major expedition to the remote Prince Charles Mountains, some 500 kms inland from Australia's Mawson station, returned to Hobart today aboard the resupply ship Polar Bird. The expedition was a joint Australian-German program.

Expedition leaders Professor Chris Wilson and Dr Norbert Roland said that the expedition was an outstanding success, both in terms of the tremendous logistical support that was provided and the extensive scientific work."

Parliamentary Secretary for the Antarctic Dr Sharman Stone agreed, stating "the expedition was a great piece of international cooperative research."

Scientists expect that samples recovered from the rarely visited Prince Charles Mountains will provide significantly better information on the geological and glaciological structures of the continent.

"This information will improve knowledge of the processes by which landform and ice interact – an essential part of understanding global warming," said Dr Wilson.

In studying the isolated Prince Charles Mountains, and the nearby Gamburtsev Mountains which are completely covered by ice, the expedition has also used them as 'dip sticks' to measure the past height of the ice sheet by mapping the height of old glacial deposits above the current ice surface.

As Australia and eastern Antarctica were once joined and have similar geological characteristics, the research will also reveal much more about the physical processes that formed Australia.

Samples have been collected to identify which periods of mountain building were important to the growth of the modern mountains in Antarctica and the ice sheet that drapes them.

A major surprise has been the discovery that some time over 500 million years ago, the area was not mountainous but a deep basin that accumulated sediment.

The expedition was the first in the region to use both field geology and airborne geophysics and was assisted by the use of a fixed-wing Twin Otter aircraft, carrying instruments for measuring the magnetic properties and density of the underlying rocks. These measurements will allow the mapping of rock hidden by the ice sheet.

The Prince Charles Mountains' current exposure above the ice plateau reveals the best geological cross section through east Antarctic and their investigation will help reveal the physical history and past climates in the most poorly understood mountain outcrop in the region.