What is glacier and what are the types of glacier? Geo Thinking

Glacier and its Types

Glacier:

   The moving ice mass downslope under the impact of gravity is called Glacier. About 10% of the Earth's surface is now covered by glaciers. About 2-3 million years BP glaciers extended over almost one third of the Earth's lithospheric surface. Glaciers are formed due to accumulation of ice above Snow Line under extreme cold climate. Snow Line is generally defined as a zone between permanent and seasonal snow. In fact snowline denotes that height above which there is permanent snow cover and thus it corresponds to the the level where average temperature is always below freezing point during the warmest month of the year. The snow line is at the lowest height ( 0 m or sea level ) in the Polar region and and increases equatorward where it tends to between 500 to 6000 m. The estimated number of all types of glaciers all over the world ranges between 70,000 and 200,000. The areas of accumulation huge volume of ice are called snow-fields which generate of different dimensions. The glaciers grow by gradual transformation of Snow into granular snow, then into firn or neva and finally into solid glacial ice. Snow is a fluffy mass of loosely pact snowflakes of very low density having an open feather-like appearance. Semi-compacted snow due to the weight of overlying snow is transformed into granular snow of denser form. Such angular snow is called firn or neve. Further compaction of granular snow produces pure solid glacial ice. 

Types of glaciers:-

Glaciers are generally divided into 22 broad categories viz. (a) Mountain or valley glaciers,  and (b) Continental glaciers.

       The body of ice moving down from under the impact of gravity through the valley Border ed by Rock Valley walls in the mountains is called mountain Glacier or Valley Glacier.

       Continental glaciers are, in fact extensive ice sheets. These are called continental glaciers because they cover most part of the continent. At present the the biggest Continental glaciers are Antarctic Continental Glacier and Greenland ice sheets. The Antarctic Continental Glacier having an average thickness of 400 m and covering an area of 8 million square kilometres.

A photo of glacier:-