Aim: What are Glaciers?

I. Glacier – found at high altitudes and high latitudes. These are locations where more snow falls during the winter than melts in the summer. The snow accumulates and compaction and recrystallization changes it to glacial ice.

A. Alpine Glacier – glaciers found in high mountains.

1. Cirques – bowl-shaped holes that are gouged out from alpine glaciers.

B. Continental Glaciers - large ice sheets like those found in Antartica and Greenland.

1. Glacial till – unsorted sediment that glaciers carry, push, or drag as they move. These sediments may range in size from large boulders to the finest clay.

a. Large fragments in ice form parallel striations or grooves in the surface indicating the direction the glacier was moving.

b. Erratics – large boulders scattered over a landscape from melting ice.

2. Glacial valley is in the shape of a “U”

3. Moraine – feature that is made of till.

4. Terminal Moraine – a ridge marking the farthest advance of a glacier.

5. Outwash plain – a broad area in front of the terminal moraine deposited by water from the melting glacier.

6. Kettle holes – depressions resulting from melting block of ice that were buried in either the moraine or the outwash.

7. Drumlins – hills shaped like the back of the spoon. Also, can indicate the direction in which the glacier was moving.

8. Most of the soils found in New York State and Pennsylvania are thin, rocky, and poorly developed, made of weathered glacial till.

Glacier Movement