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The Shape of the Ice: Using Maps to Learn About Antarctic Topography data | hook | main | background & resources | student Background 98% of Antarctica is covered with ice. The ice has formed from snowfall over hundreds of thousands of years. This is despite the fact that the interior receives less that 5 centimeters of precipitation annually. Most of this ice is contained in an ice sheet that has an average thickness of over 2000 meters. This makes Antarctica the highest continent on Earth. The largest portion is the East Antarctic Ice Sheet which reaches a maximum thickness of 4,776 meters. Drilling projects have produced ice cores that indicate that the ice at the base of the sheet is about 500,000 years old. The ice sheet been present in some form for several million years. The East Antarctic Ice Sheet is land-based which means it rests on bedrock that is mostly above sea level. The smaller West Antarctic Ice Sheet contains only one-eighth as much ice. It is a marine-based ice sheet, resting mainly on rock that lies below sea level. The underlying bedrock has been depressed about 600 meters due to the immense weight of the ice. Much of it lies below sea level, especially under West Antarctica. The ice flows outward toward the edges of the continent. At the South Pole this movement is about 10 meters each year. Much of the West Antarctic Ice Sheet moves down fast-moving ice streams (up to 1 km/year) to the Ross and Ronne ice shelves. Several ice shelves are found along the edge of the continent. Though connected to the land, they float on the surface of the sea. They are often hundreds of feet thick. Eventually, the ice breaks off from ice shelves and glaciers forming icebergs which drift north and finally melt. Resources and Reference Materials International Centre for Antarctic Information and Research website http://www.iac.org.nz ANTARCTICA 1996, Children's Television Workshop, a booklet prepared by the National Science Foundation. Multiple copies are available at low cost. 1-800-228-4630 ANTARCTICA: GLACIOLOGICAL AND GEOPHYSICAL FOLIO A series of beautifully detailed maps of Antarctic ice and rock. Published by the Scott Polar Research Institute http://www.spri.cam.ac.uk.publist.htm USGS Learning Web, hypercard animations of the Antarctic Ice Sheet. http://www.usgs.gov/education/animations Back to: TEA Activities Page |