what is a glacier?

Question

may be related to cold region

Answer 1

A huge mass of ice slowly flowing over a land mass, formed from compacted snow in an area where snow accumulation exceeds melting and sublimation.

Answer 2

any large mass of perennial ice that originates on land by the recrystallization of snow or other forms of solid precipitation and that shows evidence of past or present flow. A glacier occupying an extensive tract of relatively level land and exhibiting flow from the centre outward is commonly called an ice sheet.

Exact limits for the terms large, perennial, and flow cannot be set. Except in size, a small snow patch that persists for more than one season is hydrologically indistinguishable from a true glacier. One international group has recommended that all persisting snow and ice masses larger than 0.1 square kilometre (about 0.04 square mile) be counted as glaciers.

Answer 3

A glacier is a large, long-lasting river of ice that is formed on land and moves in response to gravity. A glacier is formed by multi-year ice accretion in sloping terrain. Glacier ice is the largest reservoir of fresh water on Earth, and second only to oceans as the largest reservoir of total water.
Glaciers can be found on every continent, including on the greater Australian continent. Glaciers are more or less permanent bodies of ice and compacted snow that have become deep enough and heavy enough to flow under their own weight.

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Answer 4

Glacier

An immense field or stream of ice, formed in the region of perpetual snow, and moving slowly down a mountain slope or valley, as in the Alps, or over an extended area, as in Greenland.

Answer 5

A glacier is a field of densely packed ice that is so Harvey that it crushes anything beneath it into dust if it is rock! and a glacier can only be in very cold climates or it would melt. the ice in the glacier is in part three thousand years old the deeper you go into to it .

Answer 6

glacier is the huge blocks of ice

Answer 7

A large patch of ice, usually snow-covered, usually on the side of a mountain, that remains frozen all year round.

Answer 8

its a big chunk of ice that can pust a bunch of rocks together. their are glacier parks.

Answer 9

See, in high altitude regions,,,,,,,,,,,,,, water converts into ice due to very less temperature,,,,,,,,,,,,,

due to anomalous behavious of water,,,,,,,,,,,,,, that is its starts expanding at 4 degree celcius,,,,,,,,,,, only surface area of water gets convert to the ice,,,,,,,,, but the inner regions always remain in liquid form i.e. water,,,,,,,,,,,,,,,

such conditons are very terrible,,,,,,,,,,,,,, becoz many of the times animals including human unable to judge the thickness of ice,,,,,,,,,,,, and get trapped in that cold water and unable to move upward becoz the upper portion of water again converted into ice,,,,,,,


such form of conditions of ice and water is called glacier,,,,

Answer 10

glacier, moving mass of ice that survives year to year, formed by the compacting of snow into névé and then into granular ice and set in motion outward and downward by the force of gravity and the stress of its accumulated mass. Glaciers are usually found in high altitudes and latitudes.
Classification

Glaciers are of four chief types. Valley, or mountain, glaciers are tongues of moving ice sent out by mountain snowfields following valleys originally formed by streams. In the Alps there are more than 1,200 valley glaciers. Piedmont glaciers, which occur only in high latitudes, are formed by the spreading of valley glaciers where they emerge from their valleys or by the confluence of several valley glaciers. Small ice sheets known as ice caps are flattened, somewhat dome-shaped glaciers spreading out horizontally in all directions and cover mountains and valleys. Continental glaciers are huge ice sheets whose margins may break off to form icebergs (see iceberg). The only existing continental glaciers are the ice sheets of Greenland and Antarctica, but during glacial periods they were far more widespread. Glaciers may be classified as warm or cold depending on whether their temperatures are above or below −10°C (14°F).

Geological Impact

Glaciers alter topography, and their work includes erosion, transportation, and deposition. Mountain glaciers carve out amphitheaterlike vertical-walled valley heads, or cirques, at their sources. They transform V-shaped valleys into U-shaped valleys by grinding away the projecting bases of slopes and cliffs and leveling the floors of the valleys; in this process tributary valleys are frequently left “hanging,” with their outlets high above the new valley floor. When the tributary valleys contain streams, waterfalls and cascades are formed, such as Bridal Veil Falls of Yosemite National Park. Elevations over which glaciers pass usually are left with gently sloping sides in the direction from which the glacier approached (stoss sides) and rougher lee sides. Humps and bosses of rock so shaped are known as roches moutonnées.

The debris from glacial erosion is carried upon, within, and underneath the ice. The debris frozen into the underside of the glacier acts as a further erosive agent, polishing the underlying rock and leaving scratches, or striae, running in the direction of the movement of the glacier. Glacial deposits are often known as till or drift. The melting of the ice in summer forms glacial streams flowing under the ice, while the retreat of a large glacier sometimes leaves a temporary glacial lake, such as the ice age Lake Agassiz. Fjords generally owe their origin to glaciers.

Glacial Movement

A glacier moves as a solid rather than as a liquid, as is indicated by the formation of crevasses (see crevasse). The center of a glacier moves more rapidly than the sides and the surface more rapidly than the bottom, because the sides and bottom are held back by friction. The rate of flow depends largely on the volume of ice in movement, the slope of the ground over which it is moving, the slope of the upper surface of the ice, the amount of water the ice contains, the amount of debris it carries, the temperature, and the friction it encounters. Glaciers are always in movement, but the extent of the apparent movement depends on the rate of advance and the rate of melting. If the ice melts at its edge faster than it moves forward, the edge of the glacier retreats; if it moves more rapidly than it melts, the edge advances; it is stationary only if the rate of movement and the rate of melting are the same.

The causes of glacial movement are exceedingly complex and doubtless are not all operative on the same glacier at the same time. Important elements in glacial movement are melting under pressure followed by refreezing, which may push the mass in the direction of least resistance; sliding or shearing of layers of ice one on top of the other; and rearrangement of the granules when pressure causes melting. Sudden, rapid movements of glaciers, called glacier surges, have been observed in Alaskan and other glaciers, with evidence for such abnormal movements as the crumpled lines of surface debris found on them. It is thought that the relatively sudden movement and melting of glaciers may be indicative of climate warming.


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