During the last Ice Age, which ended approximately 10,000 years ago, 32 percent of Earth's land area was covered with glaciers. Glaciers are not landforms. The action of glaciers, however, creates landforms. It is a process known as glaciation. Glacial ice is an active agent of erosion, which is the gradual wearing away of Earth surfaces through the action of wind and water. Glaciers move, and as they do, they scour the landscape, "carving" out landforms. They also deposit rocky material they have picked up, creating even more features. The work of present-day glaciers, however, is slow and confined to certain areas of the planet. Less obvious but far more reaching has been the work of Ice Age glaciers. Many of the distinctive features of the northern landscapes of North America and Europe were formed by glaciers that once covered almost one-third of the planet's land surface.


U-shaped Valley




*The diagram above shows a few landforms that glaciers can produce.  Cirques, horns, and arêtes are commonly found in areas of high elevation.  Arêtes are a sharp-edged ridge of rock formed between adjacent cirque glaciers.  Cirques are
a bowl-shaped depression carved out of a mountain by an alpine glacier.  Within cirques a lake is sometimes found in the central depression, called a tarn. Finally, horns are a high mountain peak that forms when the walls of three or more glacial cirques intersect.  These features are usually well defined and recognizable.  Closer to sea level glaciers tend to form moraines. The pictures above and below both include moraines and other associated landforms that are carved by glaciers.  



glacial movement diagram


*The diagrams above show the process of glaciations from start to finish.  The glacier begins as an enormous ice mass with an accumulation zone, the area of a glacier where mass is increased through snowfall at a greater rate than snow and ice is lost through ablation and an ablation zone, the area of a glacier where mass is lost through melting or evaporation at a greater rate than snow and ice accumulate.  When the glacier begins to melt, or lose its accumulation zone, glacial landforms start to reveal themselves.  Quite commonly a moraine landscape is formed with different features such as hummocks, eskers, outwash plains, kettle lakes, and ice-walled lake plains.  Most of these features are pictured above. 

There are many different type of moraines such as a lateral moraine, a moraine deposited along the side of a valley glacier.  In the first diagram there is a medial moraine, which is a moraine formed when two adjacent glaciers flow into each other and their lateral moraines are caught in the middle of the joined glacier.  Along with moraines, eskers are commonly found in the once glacial landscapes.  An esker is a long, snakelike ridge of sediment deposited by a stream that ran under or within a glacier.  Another common feature is a kettle, a shallow, bowl-shaped depression formed when a large block of glacial ice breaks away from the main glacier and is buried beneath glacial till, then melts. If the depression fills with water, it is known as a kettle lake.