Glaciers are large persistentbody of ice that forms wherethe accumulation of snowexceeds its ablation (meltingand sublimation) over manyyears.
The sheer weight of a thick layer of iceand the fact that it deforms as a"plastic" material, combined withgravitys influence, causes glaciers toflow very slowly. Movement along theunderside of a glacier is slower thanmovement at the top due to thefriction created as it slides along thegrounds surface.
Approximate Worldwide Area Covered by Glaciers square kilometers)Antarctica 11,965,000 Total glacier without iceshelves and ice rises) coverage is nearly 15,000,000 squareGreenland 1,784,000 kilometers, or aCanada 200,000 little less than theCentral Asia 109,000 total area of theRussia 82,000 South American continent. TheUnited States 75,000 including Alaska) numbers listed doChina and Tibet 33,000 not include smallerSouth America 25,000 glaciated polar islands or otherIceland 11,260 small glaciatedScandinavia 2,909 areas, which isAlps 2,900 why they do notNew Zealand 1,159 add up to 15,000,000.)Mexico 11Indonesia 7.5Africa 10
Ice Sheets Ice Shelves -enormous continental - occur when ice sheets masses of glacial ice extend over the sea, and snow expanding and float on the water. over 50,000 square In thickness they range kilometers from a few hundred meters to over 1000 meters
Ice Caps Ice Streams & Outlet Glaciers -miniature ice sheets, -channelized glaciers covering less than that flow more 50,000 square rapidly than the kilometers. They surrounding body of form primarily in polar and sub-polar ice regions that are relatively flat and high in elevation.
Ice fields Mountain Glaciers - similar to ice caps, - develop in high except that their mountainous flow is influenced regions, often by the underlying flowing out of ice topography, and they are typically fields that span smaller than ice several peaks or caps. even a mountain range.
Valley Glaciers Piedmont Glaciers -commonly originating -occur when steep from mountain glaciers or ice fields, these valley glaciers spill glaciers spill down into relatively flat valleys, looking much plains, where they like giant tongues. spread out into -may be very long, bulb-like lobes. often flowing down beyond the snow line, sometimes reaching sea level.
Cirque Glaciers Hanging Glaciers -found high on -also called ice mountainsides and aprons, these tend to be wide glaciers cling to rather than long. steep -named for the mountainsides. bowl-like hollows they occupy.
Tidewater Glaciers -valley glaciers that flow far enough to reach out into the sea. -responsible for calving numerous small icebergs.
•Glacial Erosion•Formation of GlacialLandforms
•provides drinkingwater•irrigates crops•help generateHydroelectric Power
Muir Glacier, located in Glacier Bay, Alaska, photographed by W. Field in Aug. 1941 (left)and B. Molnia in Sep. 1976 (middle) and Aug. 2004 (right). Note how the glacier hasretreated and exposed rock in 1976 that has since become lush vegetation in 2004.
The Larsen Ice Shelf in Antarctica, March 21, 1998. Taken at the beginning of theAntarctic winter, the ice shelf is clearly visible. Notice that sea ice is forming over theocean to the right the ice shelf.
The massive lobe of Malaspina Glacier is clearly visible in this photograph taken from aSpace Shuttle flight in 1989. Agassiz Glacier is to the left of Malaspina Glacier, andtowards the top of the photograph Seward Ice Field is just visible.
Retreating mountain glaciers in Bhutan. This satellite image shows the termini of severalglaciers in the Himalayan mountains of Bhutan. The glaciers have been receding over thepast few decades, and lakes have formed on the surfaces and near the termini of manyof the glaciers.
Glacier at the head of Canon Fiord, Ellesmere Island, Canada