1. Glaciers Prentice Hall Chapter 8, Section 4
By Rusty Sturken
December,
Duluth Middle School
Sixth Grade Earth Science

2. Glaciers
A glacier is any large mass of ice that moves slowly over land.
*Glaciers only form in areas where more snow falls than melts
*Snow builds up year after year
*Pressure on the snow at the bottom turns it into ice
*Gravity pulls the glacier downhill

3. Glaciers
A valley glacier is a long, narrow glacier that forms high in a mountain valley * flows a few centimeters to a few meters per day
A continental glacier is a glacier that covers much of a continent or large island
*much larger than valley glaciers
*spreads out like pancake batter
* cover Antarctica and Greenland

4. Glaciers Valley glacier Continental glacier
pubs.usgs.gov/of/2004/1216/images/mendenhall.gif

5. Continental Glaciers
Continental glaciers cover about 10% of Earth’s surface
The glacier covering Antarctica is over 14 million square kilometers and 2 kilometers thick
An Ice Age is a time when continental glaciers cover large parts of Earth’s surface
* The last ice age ended 10,000 years ago.
* Ice has covered 1/3 of Earth

6. Glacial Erosion
The two processes by which glaciers erode the land are plucking and abrasion
Plucking is the process when glaciers pick up rocks as they flow over the land, the rock freezes to the bottom of the glacier
Abrasion is the grinding away of rock by other rock particles carried in water, ice, or wind. Rocks frozen to the bottom of a glacier scrape across rocks on the Earth’s surface.

7. Glacial Deposition
When a glacier melts, it deposits the sediment it eroded from the land, creating various landforms.
Till is the mixture of sediments that a glacier deposits directly on the surface of the Earth.
A moraine is a ridge of till deposited at the edge of a glacier.
A terminal moraine is the ridge of till at the farthest point reached by a glacier.

8.
Great website

9. Moraines Terminal moraines and end moraines are the same thing

10. Long Island, N.Y. is a terminal moraine from the last ice age

11. Glaciers

12. Formations from glaciers
Moraines
Cirques(bowls)
Arêtes
Horns
Fiords
U-shaped valleys
Glacial lakes
Kettle lakes
Background photo from:
Teton Glacier in Grand Teton National Park, Wyoming

13. See Page 272 Prentice Hall Science Explorer, Earth Science
2002, 2001 Pearson Education, Inc.

14. See Page 273 Prentice Hall Science Explorer, Earth Science
2002, 2001 Pearson Education, Inc.

15. Cirque A bowl-shaped hollow eroded by a glacier
Logan Mountains, Northwest Territories, Canada

16. Arête A sharp ridge separating two cirques (bowl-shaped hollows)
z.about.com/d/geology/1/0/K/K/arete.jpg

17. Horn
Sharpened peak formed when glaciers carve away the sides of a mountain.
Glacier N.P.

18. Fiord Form when sea level rises, filling a glacier-cut valley

19. Kettle Forms when depression in till fills with water

20. Fiord/ U-shaped valley

21. Glacial Lakes Form in long basins created by plucking and abrasion
Great Lakes
Finger Lakes in New York
Also excellent website
Excellent website

22. Pictures for backgrounds Better font Animation
THANK YOU to all of my Sixth Grade students who helped me improve my Powerpoints
You helped me with:
Pictures for backgrounds
Better font
Animation
Figuring out what works or doesn’t
I still have a long way to go