UNIT 8 Surface processes Biology and Geology 3. Secondary Education TYPES OF GLACIERS

UNIT 8 Types of glaciers What is a glacier? Glaciers are enormous masses of ice which are formed due to accumulation, compaction and re-crystallisation of the snow deposited in very cold regions (the majority of them remote) of the earth’s surface. There are two main types of glacier: Alpine or valley glaciers Alpine or valley glaciers Polar cap glaciers Polar cap glaciers Click on a type of glacier to find out more Biology and Geology 3. Secondary Education

UNIT 8 Valley or alpine glaciers These are found in high mountains and they normally flow down valleys that were previously occupied by water currents, which is why they are called Alpine or valley glaciers. There are thousands of glaciers of this kind around the world. They are small compared to polar glaciers. Types of glaciers Biology and Geology 3. Secondary Education

UNIT 8 They can be short, or can have tongues which are hundreds of kilometres in length, which sometimes divide into a number of tongues. They advance down the valleys very slowly (they move just a few centimetres a day) and their action on the surface creates the characteristic U- shaped valleys. Valley or alpine glaciers Types of glaciers These are found in high mountains and they normally flow down valleys that were previously occupied by water currents, which is why they are called Alpine or valley glaciers. There are thousands of glaciers of this kind around the world. They are small compared to polar glaciers. Biology and Geology 3. Secondary Education

UNIT 8 Polar cap glaciers They are large accumulations of ice which cover enormous areas compared to Alpine glaciers:10% of the earth’s surface, in fact. They are located in the polar regions, which are very favourable areas for the accumulation of ice due to the low level of solar radiation they receive. Types of glaciers Biology and Geology 3. Secondary Education

UNIT 8 They flow in all directions from the different areas of accumulation, concealing the entire surface. When they reach the bays on the coast, they form large, flat masses of floating ice called ice shelves. Ice shelf Polar cap glaciers They are large accumulations of ice which cover enormous areas compared to Alpine glaciers:10% of the earth’s surface, in fact. They are located in the polar regions, which are very favourable areas for the accumulation of ice due to the low level of solar radiation they receive. Types of glaciers Biology and Geology 3. Secondary Education

UNIT 8 There are only two glaciers of this type: - At the North Pole: in Greenland, it covers 1.7 million Km 2 with a thicknesses of between 1,500 and 3,000 metres. - At the South Pole: the Antarctic encompasses 13.9 million Km 2 with a maximum thickness of 4,500 metres. Polar cap glaciers Types of glaciers Biology and Geology 3. Secondary Education