Glacial motion

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Glacial movement is a glacier motion, which can be likened to a river of ice. It has played an important role in sculpting many landscapes. Most of the world's lakes occupy the basins that are rubbed by glaciers. Glacial movement can be rapid (up to 30 m/day, observed on Jakobshavn IsbrÃÆ'Â| in Greenland) or slow (0.5 m/year on a small glacier or in the center of the ice sheet), but usually about 1 meter/day.

Video Glacial motion

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Glacier motion occurs from four processes, all driven by gravity: basal sliding, glacial earthquakes producing fractional movements of large sections of ice, bed deformation, and internal deformation.

• In the case of basal sliding , the entire glacier slid over the bed. This type of movement is enhanced if the soft sediment bed, if the glacier base is melted and if the melt water is common.
• Bed deformation is thus usually limited to shifting areas. Seasonal melt depth and penetration beneath the glaciers indicate seasonal acceleration and the deceleration of ice flow affecting all ice layers.
• Some glaciers under the globe of glacial glacial borders of Manhattan and as high as the Empire State Building can move 10 meters in less than a minute, a surprise enough to produce moderate seismic waves. " There is an increase in the pattern of this ice earthquake - "Earthquakes ranged from six to 15 per year from 1993 to 2002, then jumped to 20 in 2003, 23 in 2004, and 32 in the first 10 months of 2005." A glacier that froze up to his bed did not experience basal sliding.
• Deformation internally occurs when the ice weight causes ice crystal deformation. This happens most easily near the glacier bed, where the pressure is highest. There are glaciers that move mainly through sliding, glacial earthquakes, and others that move almost entirely through deformation.

Maps Glacial motion

Movement terminus and balance of mass

If the terminus glacier moves ahead faster than melt, the net result is advanced. Glacier rejuvenation occurs when more material misses from terminus than is recharged by the stream to the region.

Glaciologists consider that the tendency of mass balance for glaciers is more fundamental than the progress or decline of individual glacier tips. In the years since 1960, there was a noticeable drop in the overall volume of glaciers worldwide. This decrease correlates with global warming. As thin lumps, due to loss of mass it will slow down and crevassing will decrease.

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Landscape and geology

Studying the glacial movement and the resulting landscape requires tools from different disciplines: physical geography, climatology, and geology are one of the areas sometimes grouped together and called earth sciences.

During the Pleistocene (the last ice age), a large sheet of ice called a continental glacier develops in most of the earth. This continental glacier movement creates many familiar glacial landscapes. As the glaciers expand, due to accumulated ice and snow weights, they destroy and flatten surface rocks, creating eroded landforms like striations, cirques, and hanging valleys. Then, as the glaciers retreat leaving behind crushed rock and sand, settling land forms are created, such as moraines, eskers, drumlins, and kames. The stone walls found in New England (northeastern United States) contain a lot of glacial erratic, rocks dragged by miles of glaciers from the origin of their bedrock.

At some point, if the Alpine glacier becomes too thin it will stop moving. This will result in the end of basal erosion. The flow that flows from the glacier will then become clearer as the glacial flour is reduced. Lakes and ponds can also be caused by glacial movements. The lake kettle is formed when the glacier retreats leaving the bottom of the ice. Moraine stranded lake occurs when the flow (or snow runoff) is blocked by glacial.

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See also

• Cryoseism
• Glacial earthquakes
• the glacier lake overflow

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References

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External links

• How the glaciers are formed and flow
• Glacier mass balance trends
• Glacial facial animation
• Go forward and retreat from Columbia Glacier in Prince William Sound
• Physical geography of the glacial landscape
• Links to more online glacier resources
• Climate Research Glacier North Research

Source of the article : Wikipedia