MondayMarch 21, 2011

(Landforms Created by Glacial Erosion; Glacial Deposits)

The Launch PadMonday, 3/21/11

Why are most glaciers in the world today

receding?

The Launch PadMonday, 3/21/11

More ice is melting every summer than can be replaced by

snowfall the next winter. This could be caused by a gradual

increase in world temperatures (global warming.)

Announcements??

Assignments For This Six-Weeks Date Issued Date Due

Video Quiz - Lakes, Rivers, and Other Water Sources 2/27 2/27

WS - Running Water and Groundwater (Part 1) 2/25 3/4

PowerPoint Project – Rivers (P5 only)

2/28 3/3

WS - Running Water and Groundwater (Part 2) 3/2 3/9

Video Quiz - Groundwater 3/3 3/3

Cornell Notes - Ice 3/8 3/9

WS - Ice 3/9 ??

Continue Worksheet

Ice

Landforms Created by Glacial Erosion

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

Glacial DepositsGlaciers pick up and transport a huge load of debris as they slowly

advance across the land.Ultimately, these materials are deposited when the ice melts.

In regions where glacial sediment is deposited, it can play a significant role in forming the physical landscape.

Long before the theory of an extensive Ice Age was proposed, much of the soil and rock debris covering portions of Europe was recognized as

coming from elsewhere.At the time, these foreign materials were believed to have been

“drifted” into their present positions by floating ice during an ancient flood.

Therefore, the term drift was applied to this sediment.Today, glacial drift is a term for sediments of glacial origin, no matter

how, where, or in what form they were deposited.

Glacial DepositsTypes of Glacial Drift

Till refers to material that is deposited directly by ice.

Glacial DepositsTypes of Glacial Drift

Stratified drift is a sorted sediment deposited by meltwater.

Glacial DepositsTypes of Glacial Drift

Boulders found in till or lying free on the surface are called

glacial erratics if they are different from the bedrock

below.Erratics must have been

derived from a source outside the area where they are

found.