Landforms of Glacial erosion

Cirques:
A cirque is a large armchair-shaped hollow high up in the mountains. It has three steep sides and may contain a lake. it is the birth place of a glacier.

It is formed by snow collecting in the mountain hollows was compressed to form ice. The ice plucked rocks from the sides of the hollow. It used them to deepen the and widen the hollow by abrasion. The ice continued to build up until it overflowed the hollow and began to move down hill. As the Glacier finally moves away and the ice finally melts a small lake , called a tarn will be trapped in th hollow

Here is a picture to help you understand.

I got this image from About.com
An example of this a cirque is the Coomshingaun in the Comeragh Mountains.


Aretes:
An Arete is a narrow steep-sided ridge.

When two cirques form side by side the land between them was eroded until only a narrow ridged remained.

When three or more cirques form around one mountain, only a steep-sided remnant of the original mountain remains. this is called a Pyramidal peak.


This is an example of aretes and pyramidal peaks. I got this image from www.uwsp.edu.

Glaciated valleys:
A Glaciated or U- shaped valley has a wide, flat floor and steep sides. It normally follows a direct coarse.
After the glacier moved out if the cirque it moved down the mountainside, taking the easiest route available. That route was through the existing river (V-shaped valley) valley.
The glacier widened, deepened and straightened the river valley changing it to a U-shaped valley. In doing this it cut off the heads off the interlocking spurs, leaving truncated spurs.

I got this image from www.geo.umn.edu

How Ice Erodes.

As ice moves, it shapes the landscape by erosion.It does this by Plucking and Abrasion.

Plucking- As the ice moves, there is some melting at the base of the glacier. If the ice stops, this meltwater freezes and sticks on to the rock. As the glacier moves forward again, it pulls or plucks chunks of rocks from it.

Abrasion- As the plucked rocks are carried away by the ice, they scrape or scratch the surface over which the glacier passes, like a giant sheet of sandpaper. These scratches are called striae.

I got this information from a book called New Geo by Liam Ashe and Kieran McCarthy and this image from Wikimedia.

The different types of Glaciers

There are two main types of Glaciers-Alpine Glaciers which are found in the mountain terrains, and Continental Glaciers-which can cover larger areas.

The smallest Alpine Glaciers form in mountain valleys and are known as Vally Glaciers. Larger Glaciers can cover the entire mountain, mountain chain or even a volcano. this type in known as an ice cap.

The largest glaciers are Continental Glaciers. Antarctica and Greenland are the only place where these glaciers currently exist. These regins contain vast amounts of fresh water.

This image is a picture of a Glacier in Greenland and i got it from instablogimages.

How Glaciers are formed

Glaciers are formed when snow remains in the same place all year round.
Each year the new layer of snow compresses the previous layers. The compression forces the snow to re-crystallize, forming grains around the same shape and size as grains of sugar. Gradually the grain grow larger and the air pockets between the grains get smaller.
This causes the snow to slowly compact and increase in density. After about two winters the snow turns into firn which is and intermediate state between snow and glacier ice. At this point it is about half as dense as water.
Over time, larger ice crystals form and become so compressed that the air pockets are very tiny. In very old glacial ice, crystals can reach several inches in length. For most glaciers this process takes over a hundred years.

Image of a Glacier

This is an image of a Glacier making its way down the mountain. I got this image from a site called Omega which is the Development of Operational Monitoring System for European Glacial Areas

What is a Glacier?

A Glacier is commonly Known as a Frozen river made out of ice and snow. This is the easy way of putting it.
The more difficult way is a mass of land ice, formed by the further recrystallization of firn, flowing continuously from higher to lower elevations.
This term covers all such ice accumulations from the extensive continental glacier to tiny snowdrift glaciers

or

A multiyear surplus accumulation of snowfall in excess of snow melt on land and resulting in a mass of ice at least 0.1 km 2 in area that shows some evidence of movement in response to gravity. A glacier may terminate on land or in water
As you can see there are many different explanations for the Glacier which may confuse you but i assure you that they are all quite simple.

Introduction

Hello and welcome to the wonderful cold world of "Glaciers"!!! This is my Enviormentional studies Project and i will be up dating this blog for the next five weeks. Durning these weeks i will be posting new and intresting facts about glaciers! Such as how they were formed,different types of glaciers, what effects that they have on the earths surface and how they shape the earth,how they transport materials such as rocks to other areas and also many other intresting and gripping facts!!I will also include some tourist attractions and areas which you can visit yourself and see just how intresting they can be!!!!