Glaciers & Glaciation

1. Glaciers & Glaciation

2. Glacier: a large, long-lasting mass of ice, formed on land that moves under the influence of gravity and its own weight Glaciers form by accumulation and compaction of snow Packed snow becomes firm Then refreezes to ice Glaciers

3. Glaciation Types • Alpine glaciation: found in mountainous regions • Continental glaciation: exists where a large part of a continent is covered by glacial ice Cover vast areas

4. Two types of glaciers Alpine Glaciers Continental Glaciers

5. Features of Alpine Glaciation

6. Arete Horn A sharp, jagged, knife-edge ridge between two cirques or glaciated valleys. A steep-sided, pyramid- shaped peak produced by headward erosion of several cirques.

7. Cirques Glacial Valley Horn Arete

8. Hanging Valley A glacial trough of a tributary glacier elevated above the main trough.

9. a lake in a cirque Tarns

10. Glacier Braided Stream Outwash Plain A plain formed by a blanket-like deposition of glacial outwash.

11. U-shaped Valleys

12. Glacial Till Glacial Sediments ___________________ Unsorted and unstratified sediments that collect directly from the melting of ice. Unstratified sheets of clayey silt that are transported beyond the margins of a glacier by wind and/or braided streams ______________________ Loess

13. Moraines Moraines are large piles of rocks composed of Unsorted Till (glacial debris) Unsorted Till

14. Lateral Moraines Medial Moraines

15. Drumlins Ice Flow

16. Kettles A round lake in a depression in glacial drift... formed by melting of an isolated block of ice.

17. Kame A steep-sided mound of stratified drift... that formed in contact with glacial ice.

18. Erratic A boulder that was carried far from its source by a glacier.

19. Esker A long, narrow, sinuous ridge of stratified drift... deposited by meltwater streams flowing beneath the glacier.