Basal sliding
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Basal Sliding is the act of a glacier sliding over the bed before it due to meltwater under the ice acting as a lubricant. This movement very much depends on the temperature of the area, the slope of the glacier, the bed's sediment size, the amount of meltwater from the glacier, and the overall glaciers size. The movement that happens to these glaciers as they slide is that of a jerky motion where any seismic events, especially at the base of glacier, can cause movement. Most movement is found to be caused by pressured meltwater or very small water saturated sediments underneath the glacier. This gives the glacier a much smoother surface in which to move as opposed to a harsh surface that tends to slow the speed of the sliding. Although meltwater is the most common source of basal sliding, it has been shown that water-saturated sediment can also play up to 90% of the basal movement these glaciers make.
The most activity seen from basal sliding is within thin glaciers that are resting on a steep slope, and this most commonly happens during the summer seasons as opposed to the winter due to the fact that the sun melts away some of the glacier thats exposed. Factors that can slow or stop basal sliding relate to the glaciers composition and also the surrounding enviroment. Glacier movement is resisted by debris, whether it is inside the glacier or under the glacier. This can affect the amount of movement that is made by the glacier by a large percentage especially if the slope on which it lies is low. The traction caused by this sediment can halt a steadily moving glacier if it interfers with the underlying sediment or water that was helping to carry it.
[edit] See also
[edit] Reference
- Easterbrook, D. J. 1999. “Surface Processes and Landforms,” 2nd ed. Prentice-Hall, Inc. p. 297-300.
