Huge Iceberg Peels Off Antarctic Ice Shelf
© Environment News Service (ENS) 2000
March 23, 2000
WASHINGTON, DC, March 23, 2000 (ENS) - A large iceberg broke off the Ross Ice Shelf in Antarctica near Roosevelt Island early this week. Scientists say the massive iceberg could drift to sea within the next few days.
The iceberg has begun peeling away from the main ice sheet only 200 miles (322 kilometers) east of the National Science Foundation's McMurdo Station as measured from the berg's western edge.
Among the largest ever observed, the iceberg is about 170 miles long by 25 miles wide (274 kilometers by 40 kilometers). Its 4,250 square mile (11007 square kilometer) area is almost as large as the state of Connecticut.
The iceberg was formed from glacial ice moving off the Antarctic continent and calved along pre-existing cracks in the Ross Ice Shelf.
The splitting off of the iceberg moves the northern boundary of the ice shelf about 25 miles (40 kilometers) to the south, a loss that would normally take the ice shelf as long as 50 to 100 years to replace.
Cracks in the Antarctic ice shelf have been closely observed since the advent of remote sensing by satellite and are of particular interest to scientists studying the possible effects of global warming. The breakoff of this iceberg is believed to be part of a normal process in which the ice sheet maintains a balance between constant growth and periodic losses.
Such a berg might bounce against the main ice shelf for several days, sometimes breaking apart, before drifting to sea. National Science Foundation (NSF) supported researcher Doug MacAyeal at the University of Chicago is already at work modeling the potential path of the iceberg, based on the science of iceberg drift dynamics.
Polar scientists are concerned that it could drift into McMurdo's shipping lanes, which are used to supply the scientific research station at McMurdo during the Southern summer, which begins in October. The rate and direction of drift and the breakup of an iceberg depend on the ocean tides in the area.
McMurdo, Antarctica's largest station, is the logistics hub of the U.S. Antarctic Program. Established in December 1955, it has airports and a seaport, research laboratories and support facilities. It is built on the bare volcanic rock of Hut Point Peninsula on Ross Island, the most southerly solid ground that is accessible by ship.
The National Science Foundation at McMurdo through the U.S. Antarctic Program, coordinates most U.S. scientific research in the Antarctic.
McMurdo Station serves as a gateway for field teams studying astronomy, atmospheric sciences, biology, earth science, environmental science, geology, glaciology, marine biology, oceanography and geophysics.