GLACIERS AND FORMATION OF GLACIERS

GLACIERS & FORMATION OF GLACIERS

• In simple terms, a glacier is a large body of ice that moves slowly.
• It mostly lives in the valleys of high mountains and the colder Polar Regions.
• However, not every big chunk of ice is a glacier.
• The area of ice must be at least 0.6 square miles and more than 164 feet thick to be called a glacier. Snow is the main thing that glacier ice is made of.
• In other words, glaciers form in places where it snows more in the winter than it melts in the summer.
• Extremely low temperatures in these places make it possible for a lot of snow to pile up and freeze.
• Every year, when this happens, snow slowly builds up. The places where snow stays all year are known as snowfields.
• It takes a lot of snow to build up enough for glacier ice to form.
• It's very important that the snow that falls in the winter be much heavier than the snow that melts in the summer.
• Water crystals in the shape of hexagons are snowflakes. You should know, though, that layers of soft snowflakes are not yet glacier ice.
• The snowflakes that are buried under it get much more tightly packed together as more snow falls.
• When the snowflakes are packed closely together, they become round, while the hexagonal snowflakes lose their shape.
• The round grains that are buried deep become tightly packed over time, forcing out a lot of the air that is trapped between them.
• Firn are the snowflakes that look like grains. They take about a year to form.

Types of Glaciers

Alpine glaciers

• They look like mountain chains.
• They form high up in the mountains and look like bowls.
• The ice below the pulling glacier starts to melt and is pushed into a valley as the glacier grows.

Valley glaciers

• These are big mountain glaciers that stay in valleys with steep walls.
• Most of the time, they follow the line of an old river bed.
• They carry rock pieces that they discover along the way or that fall into them.
• Valley glaciers moving downhill cause a lot of erosion, which shapes the valley into a U shape instead of the V shape that rivers usually make in the early stages of erosion.

Piedmont Glacier

• When a big Alpine glacier moves to the base of a mountain range, it forms a pitched glacier.
• It can grow bigger than its valley source when it's at the base of a mountain range.
• They keep getting bigger because mountain glaciers keep feeding them.

Cirque glacier

• When glaciers wear away rock, they leave behind a valley that looks like an amphitheater.
• The mountain's cirque ice looks like bowls.
• Most of the glaciers in the Cirque are not very big—less than one km across.
• As the glaciers fall, they join with other glaciers to form a wider valley glacier.

Tidewater Glaciers

• When Alpine glaciers melt and fall into the ocean, these types of glaciers rise.
• Later, pieces of them break off and float on the water as icebergs.

Ice sheet

• When a lot of ice moves downhill in every direction without being stopped, it's called an ice sheet.
• The ice sheet in Greenland is a prime example of one.

Icecap

• An icecap is a dome-shaped glacial mass that is not limited in any way.
• It has the ability to move in any way.
• It can cover an island or mountain group all the way around.
• An ice cap turns into an ice sheet when it covers more than 50,000 square kilometers.