Chapter 19- Glacial Modifications Of Terrain

Question 1

What impacts do glaciers have on the landscape?

Answer 1

Erode → Transport → Deposit

Question 2

How much of Earth’s land surface was covered by ice during Pleistocene glaciation?
How much today?

Answer 2

-approx. 30%
-today: approx. 10%
Contemporary glaciation ongoing in Antarctica/Greenland ice sheets and scattered mountain
glaciers.

Question 3

Erosion

Answer 3

plucking and abrasion, or transportation via meltwater (glacial flour or glacial milk)

Question 4

Glaciations past and present:
How long did the Ice Age last?

Answer 4

-about 100,000 years
At least five major ice ages in Earth’s history.
Earliest > 2 billion years ago; most recent began 3 million years ago.

Question 5

Are we currently in an ice age?

Answer 5

yes, we are in the interglacial period

Question 6

Accumulation zone

Answer 6

upper portion of a mountain glacier where annual build up exceeds any
ice loss.

Question 7

Ablation zone

Answer 7

lower portion of a mountain glacier with a net annual loss of ice from
melting/sublimation.

Question 8

Continental Ice Sheets
How do they develop and flow?

Answer 8

Erosion by ice sheets can create Roche Moutonnée
- Deposition by ice sheets can create moraines, kettles, and drumlins
- Glaciofluvial (meltwater) features include outwash plains, eskers, kames, and lakes

Question 9

Mountain glaciers

Answer 9

• Erosion creates cirques, arêtes, horns, U-shaped valleys
• Deposition creates lateral moraines, recessional moraines, terminal moraines

Question 10

Theoretical causes of the Pleistocene Glaciations?

Answer 10

Milankovitch Cycles (wobbling Earth orbit), variations in solar output, variations in
atmospheric CO2