Erosion and DepositionbyGlaciers

Chapter 4: Topic 8

Animation Links http://highered.mcgraw-hill.com/sites/0072402466/student_view0/

chapter12/animations_and_movies.html# http://phet.colorado.edu/en/simulation/glaciers

Glacier You Tube vids The great lakes – YouTube Glaciers (3 min) Yakety Sax Glacier Cartoon formation of glacier

Study Guide- Item #1

1.       A glacier is an enormous mass of ____________________ __________________. They are formed of accumulated and compressed layers of _____________________ that pile up year after year in cold places.

moving ice

snow

Study guide – item #2

___________ ____________ form in high elevations such as the peaks of large mountains. These are also known as ___________________ glaciers since they flow down the slopes of mountains through valleys originally carved out by streams.

Alpine glaciers

valley

Alpine (valley) glacier

Study guide- item #3

These types of glaciers (alpine) _____________________ and _________________________ the valleys into a broad ___________ shape.

widen

straighten

U

Valley Glaciation

Glacial Valley (U-shaped)

Study guide – item #4

____________________ _________________________ form near the North and South poles and cover huge amounts of land area. These are pancake-shaped and move outward in all directions form the center. All glacial movement is the result of the force of ________________________ moving ice from higher to lower elevation.

Continental glaciers

gravity

Continental glacier

Study guide- item #5

The size of a glacier changes due to changes in _________________________ - the averages in temperature and precipitation over an extended period of time. This can cause the terminus (the outer or lower edge of the glacier) to appear to move.

• Advance- glaciers grow during periods of global cooling and cover more land (“ice age”)

• Retreat – glaciers shrink and cover less land as a result of global ________________.

climate

warming

Glacial / Interglacial cycles

Study guide- item #6

The most recent ice age ended about __________________________ years ago. At this time, much of midwest (including Ohio) and northeast U.S. was covered by a large continental glacier. The remnants of this glacier covers Greenland today. This glacier started retreating as a result of global warming that continues today. The erosional effects of this glacier created the _________ ______ when it retreated. These are a major source of fresh water, recreation, and transportation today.

10, 000

Great Lakes

The Great Lakes and Finger lakes

Formation of Great Lakes

Formation of glacial lakes through differential abrasion

Hard rock Soft rock Hard rock

glacier

Hard rock Soft rock Hard rock

glacier

Hard rock Soft rock Hard rock

Glacial lake

Glacial Grooves- Kelley’s Island

Great Lakes profile

Study guide- item #7

The movement of large, heavy glaciers over the land has the power to erode, weather, and deposit rock. Continental glaciers ___________________ the landscape by scraping and eroding features. Alpine glaciers carve out ____________________ features in the mountain rocks through which they flow. These include:

 

smooth

rugged

Northern and western Ohio (glaciated)

Southeastern Ohio (unglaciated)

#7- continued

__________________________________ - sharp, pyramid-shaped peaks at the tops of mountains.

Horns

The Matterhorn

#7 - continued

__________________________________ - jagged ridges formed between two or more cirques or glacial valleys.

Aretes

#7- continued

__________________________________ - bowl-shaped depressions where glacial ice cuts into mountain walls.

Cirques

#7- continued

__________________ ________________ - smaller stream valleys that join a glacial valley by way of a steep, vertical drop. These often result in very tall waterfalls.

Hanging valleys

Yosemite Valley, CA

Study guide- item #8

The moving ice in glaciers has the power to erode (transport) everything from small soil particles to huge boulders. The material carried and eventually deposited by glaciers is called _______________ ____. Eventually this material gets deposited where the ice carrying it melts. This occurs at the terminus (outer or lower edge) of the glacier.

Glacial drift

Study guide- item #9

Glacial deposits form in one of two ways. If the drift is dropped down directly by the melting ice, it creates an unsorted (mix of different size) deposit known as ___________________. This type of deposit often forms ridges at the edge of the glacier called ___________________________.

Till (glacial till)

Moraines (terminal moraines)

MORAINE

A moraine

Glacial Erratics (till deposit)

This boulder was transported hundreds of miles by a glacier!

Study Guide- item #10

Glacial deposits are often sorted by streams of meltwater flowing from the glacier as it melts. These streams erode and deposit drift by size. These sorted deposits are known as _______ __________. These deposits form a type of alluvial fan called an

___________ __________.

 

Stratified drift

Outwash plain

Outwash

Outwash plain (stratified drift)

Outwash Plain

Study guide – item #11

Within these deposits it is common for blocks of ice that have broken away from the retreating glacier to become buried within the stratified drift. As these melt, they form small, round lakes called _______ _____________.

 

Kettle lakes

Outwash

Outwash plain (stratified drift)