Glaciers, Deserts, and Wind

Question 1

What type of glaciers exist, ands where is each type found?

Answer 1

1. Valley: a stream of ice that flows between steep rock walls from a place near the top of the mountain valley.
2. Ice sheet: enormous ice masses that flow in all directions from one or more centers and cover everything by the highest land. The only present-day ice sheets are:
   
   • Greenland
   • Antarctica

Question 2

How do glaciers move/flow?

Answer 2

1. Plastic flow: movement within the ice (>50m deep) where the pressures make the ice “plastic” instead of brittle.
2. Basal slip: gravity causes the entire mass to slip down

Question 3

What is the “glacial budget”?

Answer 3

The balance (or lack of balance) between accumulation of ice at the upper end of a glacier(zone of accumlulation) and its loss at the lower end (zone of wastage). Determines if the glacier is advancing, retreating, or stationary.

Question 4

What are five landscape features caused by Glacial Erosion?

Answer 4

1. Glacial valleys and troughs: a V-shaped valley carved by a river is turned into a U-shaped trough by a glacier.
2. Hanging valleys: side glaciers may receed before the main one and thus not cut so deep as the main valley resulting in hanging valleys and great waterfalls.
3. Cirques: Bowl-shaped depressions surrounded on 3 sides by steep rock walls as glaciers “pluck” rocks from near the head of glacial valleys
4. Aretes: snaking, sharp-edged ridges
5. Horns: pyramid-like peaks.

Question 5

What does the term Glacial Drift refer to?

Answer 5

The movement of all sediments of glacial origin, no mater how, where, or what form they were deposited.

The two types are:

• Stratified: sediment laid down by glacial meltwater.
• Till: material deposited directly by the glacier (rock debis)

Question 6

What 5 depositional landscape features are glaciers responsible for?

(Depositional means made up of deposits carried by glaciers.)

Answer 6

1. Moraines: layers or ridges of till (deposits) left by melting glacier.
2. Outwash plains: “milky” fast-moving meltwater emerging from the base of glaciers form ramp-like accumulations downstream.
3. Kettles: small depressions formed when a small block of ice becomes buried and later melts.
4. Drumlins: stream-like hills composed of till
5. Eskers: snake-like ridges composed of sand and gravel that were deposited by streams once flowing in tunnels beneath glaciers.

Question 7

What is “calving”

Answer 7

Large piece of ice break off the fronts of glaciers in a process called “calving”. Calving creates iceburgs where the glacier meets the ocean. (Only about 10% of an iceburg is visible above water because they float very low in the water.)