'Investigating the Cryospheric Evolution of the Central Antarctic Plate’ (ICECAP), is an ambitious International Polar Year project studying the underlying geology and the structure of the East Antarctic Ice Sheet and its subglacial processes. The project will explore the vast Aurora and Wilkes subglacial basins to uncover information critical to ice sheet modelling and an understanding of the role of the East Antarctic ice sheet in global climate and sea level rise.
From their base at Australia’s Casey station, scientists from the United States, the United Kingdom and Australia will explore the Aurora Subglacial Basin over the 2008–09 and 2009–10 summer seasons. This basin, about the same area as New South Wales, is one of Antarctica’s least surveyed regions, and is believed to hold the thickest ice — more than 4.5km deep. (A second campaign, based at McMurdo, will explore the Wilkes Subglacial Basin).
The ICECAP team will use instruments fitted to a Basler BT-67 turboprop aircraft, to measure the glaciological and geological properties of the basins. East Antarctica was previously regarded as less responsive to climatic changes than the smaller marine-based West Antarctic ice sheet, but recently numerous subglacial lakes have been discovered beneath East Antarctica , indicating that the ice sheet is potentially more mobile than if it were frozen everywhere to the bedrock. Satellites also show that the Totten Glacier, which dominates the ice drainage of the Aurora basin, is thinning near the coast.
On board the aircraft, high resolution ice-penetrating radar will image the underside of the ice sheet and layers within the ice, providing insight into bedrock conditions and past ice flow. At the same time a gravity sensor and magnetometer will measure the density and composition of the rock lying beneath the ice, exploring the geological character of this region, which was joined to Australia until the breakup of the Gondwana supercontinent. The aircraft will also carry a laser altimeter to map the ice surface, and GPS receivers to accurately locate the aircraft.ICECAP connects with several other projects. For example, the Australian Antarctic Division is also collaborating on aerial survey work around Dome A through the 'Antarctica’s Gamburtsev Province’ (AGAP) project . Results from AGAP and ICECAP will be combined, and also connected to the deep ice core record from Vostok, using earlier survey data.
Data collected through ICECAP and AGAP, about the ice structure and conditions at the ice-bedrock interface, will be used to improve computer models of ice flow for Antarctica. This will improve estimates of ice sheet stability, and forecasts of its reaction to climate change and impacts on global sea level.
The Australian Antarctic Division air link will be pivotal to ICECAP, enabling senior project scientists to participate by removing the barriers of time and distance. ICECAP operations from the Casey ski-way will be supported by communications and air ground support personnel, with additional support from Casey station and Antarctic Division Headquarters.
ICECAP is led by Don Blankenship from the Jackson School of Geosciences at the University of Texas at Austin, while the British and Australian contingents are being led by Martin Siegert from the School of Geosciences at the University of Edinburgh, and Tas van Ommen from the Australian Antarctic Division. The universities of Bristol, Cambridge and Melbourne are also involved.
ROLAND WARNER and JASON ROBERTS
ACE CRC and AAD