Ice Shelf


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Related to Ice Shelf: Larsen B Ice Shelf

ice shelf

[′īs ‚shelf]
(oceanography)
A thick sheet of ice with a fairly level or undulating surface, formed along a polar coast and in shallow bays and inlets, fastened to the shore along one side but mostly afloat and nourished by annual accumulation of snow and by the seaward extension of land glaciers.

Ice Shelf

 

a glacier that is floating or partially resting on the bottom and flowing from the shore into the sea in the form of a plate that diminishes in thickness toward the edge and terminates in a cliff.

The ice shelf is a continuation of land ice sheets. More rarely, it is formed by the accumulation of snow on sea ice and by the cementing together of accumulations of icebergs by snow and ice. Ice shelves are found almost exclusively in Antarctica. Their total area is 1,460,000 sq km; the volume is about 0.6 million cu km; and the thickness varies from 200–1,300 m at the land edge to 50–400 m at the sea edge. The accumulation area usually encompasses the entire upper surface and the coastal section of the lower surface where ice forms; in the marginal zone the ice melts on the bottom (up to 1 m per year). A large part of the loss occurs from the breaking off of icebergs (a volume at times of thousands of cu km). The rate of movement of the ice shelf, which increases toward the edge, varies from 300–800 m to 1,800 m and more per year. (The largest ice shelf is the Ross Ice Shelf.)

REFERENCES

Shumskii, P. A. “Oledenenie Antarktidy.” In the collection Osnovnye itogi izucheniia Antarktiki za 10 let. Moscow, 1967.
Atlas Antarktiki, vol. 2. Leningrad, 1969.
References in periodicals archive ?
Channels under the ice shelf caused by flowing melt-water an estimated 11 million years ago left behind formations known as "tunnel valleys," which caused severe shrinking and growing.
However, the sudden disintegrations of Larsen A and B in 1995 and 2002 respectively, and the ongoing speed-up of glaciers which fed them, focused scientific interest on their much larger neighbour, Larsen C, the fourth-biggest ice shelf in Antarctica.
The calving of the iceberg, which is likely to be named A68, reduces the size of the Larsen C Ice Shelf by around 12% and will change the landscape of the Antarctic Peninsula forever, the scientists said.
In the ensuing months and years, the ice shelf could either gradually regrow, or may suffer further calving events which may eventually lead to collapse," lead investigator Adrian Luckman said.
The Larsen C ice shelf has now been reduced in sized by a record 10 percent.
The iceberg is one of the largest recorded and its future progress is difficult to predict," said Adrian Luckman, professor at Swansea University and lead investigator of Project MIDAS, which has been monitoring the ice shelf for years.
This [mechanism] allows the ice shelf to break apart way further inland from the inside out.
Science in Progress: Ross Ice Shelf Programme," Antartica New Zealand, http://www.
The crack completely cuts through the ice shelf but it does not go all the way across it once it does, it will produce an iceberg roughly the size of the state of Delaware.
The projections show that similar levels of melt may occur across coastal Antarctica near the end of this century, raising concerns about future ice shelf stability.
Satellite images reveal that a crack in Larsen C rapidly extended tens of kilometers across the ice shelf in 2014.
The study predicts that what remains of the once-prominent ice shelf, a thick floating platform of ice, most likely will "disintegrate completely" before the end of this decade.