This outline was created by a student! Thanks Janice.
Water, Wind, and Ice Shape the Earth’s Surface
I. Glaciers carve land and move sediments.
1. Glacier- large mass of ice that moves over the land
2. Till- the sediment left directly on the ground surface by a retreating glacier
3. Moraine- a deposit of till left behind by a retreating glacier
4. Kettle Lake- a bowl-shaped depression that is formed by a block of ice from a glacier that becomes filled with water
II. Glaciers are moving bodies of ice.
A. Form in cold regions where more snow falls than melts each year.
1. On a mountain, the weight of a heavy mass of ice causes snow to flow downward.
2. On flatter land, the ice spreads out as an ice sheet.
B. As glaciers form, move and melt away, they shape landscapes.
III. Extent of Glaciers:
A. Glaciers cover about 10 percent of Earth’s land surface.
1. Glaciers have expanded during long, cold periods and disappeared during long, warm periods.
2. There are two major types of glaciers: alpine glaciers and continental glaciers.
B. Alpine Glaciers:
1. Form in mountains and flow down valleys.
2. As alpine glaciers move, they cause erosion, breaking up rock and carrying away the resulting sediment.
3. At the lower end of these glaciers, melting can occur. This drops sediment, causing streams to carry it away.
4. If thrown into the ocean, big blocks of ice may break off and become icebergs.
1. They can cover entire continents.
2. They are much larger than alpine glaciers.
3. Also called ice sheets, continental glaciers cover most of Greenland and Antarctica today.
IV. Glaciers deposit large amounts of sediment.
A. Glaciers shape the land as they melt and retreat.
1. As glaciers move, a large amount of sediment is transported.
2. Abrasion occurs and leaves visible markings when the movement of glaciers takes place.
3. When glaciers expand and advance, the deposits of sediment, or till, are left visible on the ground.
1. The ridges of till deposited at the sides of a glacier are called lateral moraines.
2. The till that marks the farthest advance is called an end moraine.
3. The till that is deposited along the bottom of a glacier is called a ground moraine.
1. Melting glaciers leave behind depressions that may eventually become lakes.
2. Landscapes shaped by glaciers are often filled with kettle lakes, (Michigan, Wisconsin, and Minnesota).
3. Many large lakes are the result of ice ages.
4. The Great Lakes were formed thousands of years ago when an ice sheet moved over the land and melted.