Glaciers Short History And Amazing Images Collection

Short History Of Glaciers:

A huge mass of ice slowly flowing over a land mass. Glaciers form over many years from packed snow in areas where snow accumulates faster than it melts. A glacier is always moving, but when its forward edge melts faster than the ice behind it advances, the glacier as a whole shrinks backward.

Large mass of perennial ice that forms on land through the recrystallization of snow and that moves forward under its own weight. The term ice sheet is commonly applied to a glacier that occupies an extensive tract of relatively level land and that flows from the centre outward. Glaciers occur where snowfall in winter exceeds melting in summer, conditions that prevail only in high mountain areas and polar regions. Glaciers occupy about 11 of the Earth's land surface but hold roughly threetofourths of its fresh water. 99 of glacier ice lies in Antarctica and Greenland.

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. 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. 

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. 

The world's glaciers are slowly disappearing. Global temperatures have risen by about 1 degree Fahrenheit over the last century with winter temps having risen as much as 7 degrees Fahrenheit in the Arctic region. 

Images:

 Glaciers  Amazing Image

 Glacier Beautiful Scenery 

   Glacier Amazing Image

  Glaciers   Amazing Image

 Glaciers Beautiful Scenery

Beautiful Scenery Of Glacier

Beautiful Scenery Of Glacier

Beautiful Scenery Of Glacier