December 8, 2006
ABC
Hobart scientists are heading to Antarctica to study the cause of enormous cracks forming in the Amery Ice Shelf.
Photo: The Amery Ice Shelf, is the largest ice shelf in East Antarctica. The last major calving event on the Amery occurred in 1962-63 and the study involves a section at the front of the shelf, affectionately called 'loose tooth'. The 'loose tooth' area covers about 30 by 30 km (roughly 19 - 22 miles). The fracture runs east-to-west and is moving at approximately 10-14 meters a day. In one year, the fracture will extend further eastwards by about 4-5 km (2 1/2-3 miles) and it will widen as it breaks off from the main ice shelf. The ice shelf itself is moving forwards in a northerly direction at about 1300 meters/yr. (Helicopter view of the 'loose tooth' fracture on Amery Ice Shelf by R. Coleman)
The cracks began forming around a decade ago and are growing at three to five metres a day.
The fractures threatened to break off a 900-square-kilometre (347-square-miles) piece of the Amery Ice Shelf, which is about the size of Tasmania.
Scientists want to know what is causing these cracks, as the last recorded activity in this part of eastern Antarctica was in the 1960s.
The head of the research, Professor Richard Coleman, says there is not enough evidence to blame global warming.
"It may be in a 50- to 60-year cycle but we would need more data to say whether it's increasing in terms of carving events due to warming of the ice shelf," he said.
Professor Coleman says with the ice already floating, it will not increase ocean levels.
http://www.abc.net.au/news/newsitems/200612/s1807679.htm