1. Glaciers 8.3

2. What are Glaciers?
Glaciers are large blocks of ice that carve out valleys and shape the continents.
They pick up sediment (till) and deposit it in the form of moraines.
Glaciers form in areas that receive snow all year or are cold enough to retain snow all year

5. How do Glaciers Form?
As snow accumulates, it condenses to form firn, which is part ice.
Eventually the weight continues to compact until it is pure ice.

6. Types of Glaciers
Valley (Alpine)Glaciers
Continental Glaciers

7. Valley Glaciers and Formations
These form high in the mountains.
They form:
Horns
U-Shaped Valleys
Hanging Valleys
Aretes
Cirques

8. Horns – Peaks left after glaciers carve around all sides of a rock

9. U-Shaped Valleys – The shape of the valley created by the glacier

10. Hanging Valley – A valley formed from a tributary leading to a larger valley.

11. Arete – A divide between 2 glaciers

12. Cirque – A depression formed at the beginning of a glacier.

14. Continental Glaciers
Continental glaciers are massive ice sheets miles thick that can cover entire continents (Greenland and Antarctica).
They are responsible for creating much of the terrain here in Illinois.
They create the following features:
Drumlins
Eskers
Kames
Kettles (Lakes)

18. Currently, we are in a warm interglacial that began about 11,000 years ago. The last period of glaciation, which is often informally called the “Ice Age,” peaked about 20,000 years ago. At that time, the world was on average probably about 10°F (5°C) colder than today, and locally as much as 40°F (22°C) colder.

20. Drumlins – Formed when glaciers smooth over old moraines

21. Eskers – Sediment deposited from streams flowing under a glacier

22. Kames – hills deposited at the end of a glacier as it retreats

26. Kettles – Depressions formed when large blocks of ice are left and melted