Glaciers are large masses of ice that originate on land from compacted snow and move due to gravity. During an ice age, large ice sheets form on continents and flow outward, carving U-shaped valleys and depositing unsorted sediment called till. Valley glaciers are smaller glaciers confined to mountain valleys that flow due to plastic deformation and basal sliding between the ice and bedrock.

1. 7.1 Glaciers

2. Ice Age
• A period of time when much of Earth’s land is
covered by glaciers.

3. Glacier
• A thick mass of ice originating on land from
the compaction and recrystallization of snow
that shows evidence of past or present flow

4. Snowline
• Lowest elevation in a particular area that
remains covered in snow all year.

5. Valley Glacier
• A glacier confined to a mountain valley, which
in most instances had previously been a
stream valley.

6. Ice sheet
• Enormous ice masses that flow in all
directions from one or more centers and cover
everything but the highest land.

7. Till
• Sediment of different sizes deposited directly
by a glacier

8. Moraine
• A ridge of unsorted sediment left by a glacier

9. Glacial trough
• V-shaped or U-shaped valley cut by glacial
movement.

10. Key Concept
• A valley glacier is a stream of ice that flows
between steep rock walls from a place near
the top of the mountain valley

11. Key Concept
• Ice sheets are sometimes called continental
ice sheets because they cover large regions
where the climate is extremely cold. They are
huge compared to valley glaciers.

12. Key Concept
• The movement of glaciers is referred to as
flow. Glacial flow happens two ways : plastic
flow and basal slip.

13. Key Concept
• The glacial budget is the balance or lack of
balance between accumulation at the upper
end of a glacier and loss, or wastage, at the
lower end.

14. Key Concept
• Many landscapes were changed by the
widespread glaciers of the recent ice age.

15. Key Concept
• Glaciers are responsible for a variety of
erosional landscape features, such as glacial
troughs, hanging valleys, cirques, arêtes, and
horns.

16. Key Concept
• Glacial drift applies to all sediments of glacial
origin, no matter how, where, or in what form
they were deposited. There are two types of
glacial drift: till and stratified drift.

17. Key Concept
• Glaciers are responsible for a variety of
depositional features, including moraines,
outwash plains, kettles, drumlins, and eskers.