Cornell Notes:

• Essential Question: What evidence do past glaciers leave behind?

• Left-side questions: • - How much ice did there used to be??• - How do glaciers weather and erode the

land?• - What does it look like? (Warning: Crazy

amounts of vocab coming up!)

This map shows a portion of North America’s present-day coastline compared to the coastline that existed during the last ice age maximum 18 000 years ago.

The North American coastline that would exist if present-day ice sheets in Greenland and Antarctica melted.

Figure 18.18BGlaciers are capable of great erosion and sediment transport.Glaciers erode the land primarily in two ways:

Plucking, or a lifting of rocks, and abrasionRocks within the ice acting like sandpaper to smooth and polish the

surface below.Rock flour is pulverized rock produced by the movement of the glacier. Striations (grooves in the bedrock) are created as the glacier slides past.

How do glaciers erode the land?

Figure 18.14AGlacial abrasion created the

scratches and grooves in this bedrock.

Glacially polished granite

What evidence does Glacial Erosion leave behind?

Certain types of special landforms can be created by glacial erosion. These include:

glacial troughs – As a glacier widens, deepens, and straightens a valley, it transforms a v-

shaped valley into a u-shaped glacial trough.hanging valleys – After a glacier has receded,

the valleys of tributary glaciers are left standing above the main glacial trough and are termed

hanging valleys.

Landforms Created by Glacial Erosion

cirques – a bowl-shaped depression at the head of a glacier that was a depression

where snow could accumulate, thus starting the formation of the glacier.arêtes – sharp-edged ridges that are

formed when cirques grow and the divide separating them becomes very narrow.

Landforms Created by Glacial Erosion

horns – several cirques surrounding a single mountain create the spires of rock

called horns.fiords - glacial troughs that became

submerged as the ice left the valley and sea levels rose following the Ice Age

Erosional Landforms Created by Alpine Glaciers

Figure 6.10 C

The Matterhorn in the Swiss Alps

Figure 6.12

Figure 6.10 (top right)

Figure 6.10 (middle right)

Figure 6.10 (bottom right)

Figure 6.11A

Figure 6.11B