What is a Glacier ?
Glacier is defined as an extended mass of ice formed by snow that falls and accumulates with the years and moves very slowly, either descending means from high mountains to down, as in the valley glaciers, or moving outward from centers of accumulation, as in continental glaciers.
For Example : Himalayas and some other mountains like in North and South America Continental glaciers (ice sheets, ice caps) are massive sheets of glacial ice that covers the land masses. Continental glaciers are currently eroding deeply into the bedrock of Antarctica and Greenland (These are the largest ice sheets).
- Glaciers which are larger than 50000.sq kilometers are called as ice sheets.
- Glaciers move 20 to 30 meters a day. When the glaciers moves sometimes it results in earthquakes.
- Glaciers are present in 50 counties around the world.
- Actually valleys are formed by the glaciers and some of them are shaped by rivers.
How do Glaciers Form
In Order to form a glacial ice, It will take a considerable amount of snow accumulation, it is imperative that more snow accumulate in the winter than that which melts in the summer.
Those are when snow remains in one location long enough to transform into ice. Inputs come from precipitation (snow) and avalanches from the glacier sides. The majority of the snow falls in highland areas; this is known as the zone of accumulation where snow is stored. As snow continues to fall, layers build up with the underlying layers being compressed. This compression squeezes the air out of the snow resulting in ice formation. Over time this mass begins to slowly move downhill under the force of gravity. It is estimated to move between 7 and 10 km per year. This movement (flow) causes the land to undergo erosion such as abrasion and plucking. In the lowlands, it will begins to slowly melt, known and ablation, and evaporation will take place to a certain extent. These are the glaciers outputs.
The procedure will exceed accumulation in summer and in lower altitudes where temperatures are higher. If over a period of time, the annual rate of accumulation exceeds ablation, then it will advance. If ablation exceeds accumulation, it will retreat. At present the majority of the world’s remaining glaciers are retreating.
Accumulation : The buildup of the glacier due to snow being compacted into ice.
Ablation : The melting of the ice is mainly during the summer months and generally at the end of snout of the glacier”.
Calving : The splitting at the end of the glacier into smaller sections. These could become icebergs, if the glacier snout ended in the sea.
Glaciations : The effect of large masses of ice on the landscape. Compressed snow accumulates to eventually form ice and create a glacier.
Ice Sheets : These are large masses of ice which cover an entire land surface. Antarctica is the best example, as the ice sheet covers the entire continent Snout – the lower end of the glacier.
Snout : The lower end of the glacier.
Valley Glaciers : This is the Output in whole glacier process. Most commonly there are two types . These are confined by the valley sides that have already been carved out by a river. Valley glaciers can be found in all the main mountain ranges of the world, such as the Franz Josef Glacier in the Southern Alps of New Zealand, and the Rhone Glacier in Switzerland.
Features of Glaciers
Pyramid Peaks (The highland areas which were created by erosion.
Cirques or carries means starting point of glaciers.
Glacial Trough – u shaped valley cut by glacier.