Kame
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A kame is a geological feature, an irregularly shaped hill or mound composed of sand, gravel and till that accumulates in a depression on a retreating glacier, and is then deposited on the land surface with further melting of the glacier. Kames are often associated with kettles, and this is referred to as kame and kettle topography.
With the melting of the glacier, streams carry sediment to glacial lakes, building kame deltas on top of the ice. However, with the continuous melting of the glacier, the kame delta eventually collapses on to the land surface, furthering the "kame and kettle" topography.
Kame terraces are frequently found along the side of a glacial valley and are the deposits of meltwater streams flowing between the ice and the adjacent valley side. These kame terraces tend to look like long flat benches, with a lot of pits on the surface made by kettles. They tend to slope downvalley with gradients similar to the glacier surface allong which they formed, and can sometimes be found paired on opposite sides of a valley.
Kames are sometimes compared to drumlins, but their formation is distinctively different. A drumlin is not originally shaped by meltwater, but by the ice itself and has a quite regular shape. It occurs in fine grained material, such as clay or shale, not in sands and gravels. And drumlins usually have concentric layers of material, as the ice successively plasters new layers in its movement.
Kames are not normally located in proximity to one another, however in Edmonton, Alberta, Canada numerous kames are found nearby, forming the Prosser Archaeological Site. The Fonthill Kame in southern Ontario is in a densely populated area. In the United States examples can be found in Wisconsin and at the Sims Corner Eskers and Kames National Natural Landscape in Washington.
In Ontario, there are two provincial parks, both designated as IUCN category Ia nature reserves, which were created to protect important and undisturbed kame features. They are Minnitaki Kames Provincial Park and Bonheur River Kame Provincial Park.
[edit] See also
[edit] References
- Easterbrook, Don J. (1999). Surface Processes and Landforms. Upper Saddle River, New Jersey: Prentice Hall, 352-357. ISBN 0-13-860958-6.
- Tarbuck, Edward J.; Frederick K. Lutgens (2002). Earth: An Introduction to Physical Geography. Upper Saddle River, New Jersey: Prentice Hall, 351. ISBN 0-13-092025-8.
- Trenhaile, Alan (2007). Geomorphology: A Canadian Perspective. Don Mills, Ontario: Oxford University Press, 187-8. ISBN 0-19-542474-3.
