Glaciers T8: Periglacial processes and formation of features

Question 1

What is a periglacial environment?

Answer 1

An area subject to glacial processes but does not have a glacier on it. They have a mean annual temperature of less than 3 degrees c.

Question 2

what are the 3 periglacial processes?

Answer 2

1. Zonal processes
2. Intra zonal processes
3. Azonal processes

Question 3

what are zonal processes?

Answer 3

Processes that are unique to the periglacial domain.

Question 4

What are intrazonal processes?

Answer 4

The operate at a higher intensity or frequency in periglacial zones.

Question 5

What are azonal processes?

Answer 5

They operate at a greater intensity or efficiency outside the periglacial zone.

Question 6

What is permafrost?

Answer 6

Permanently frozen ground.

Question 7

What are the 3 types of permafrost?

Answer 7

1. Continuous permafrost
2. Discontinuous permafrost
3. Sporadic permafrost

Question 8

What is continuous permafrost?

Answer 8

Where the entire landscape is underlain by permafrost.

Question 9

What is discontinuous permafrost?

Answer 9

The landscape consists of areas of permafrost and unfrozen ground.

Question 10

What is sporadic permafrost?

Answer 10

Isolated bodies of permafrost within largely unfrozen ground.

Question 11

How does permafrost move?

Answer 11

1. Frost heave

2. solifluction

Question 12

What is frost heave?

Answer 12

It is a result of ice crystals forming around grains fo soil. As the ice expands the ground is pushed up creating a dome shape.

Question 13

What is solifluction?

Answer 13

It is the movement of the layer of the active layer caused by a lack of friction due to a boil up of water.

Question 14

What are the 4 types of periglacial landforms?

Answer 14

1. Patterned ground
2. Tundra polygons and ice wedges
3. Solifluction lobes
4. Pingos

Question 15

What is patterned ground ?

Answer 15

It is a symmetrical arrangement of stones on the surface of soil in cold areas. It either creates circles, polygons or stripes and its due to frost heave.

Question 16

What is a tundra polygon?

Answer 16

They are a network of cracks that penetrate the surface of permafrost due to contraction stress. When the cracks fill with snow and ice, ice wedges form.

Question 17

What are solifluction lobes?

Answer 17

The downslope movement of soil in response to freezing and thawing of ground , this leads to lobe shaped masses of debris, known as solifluction lobes.

Question 18

What are pingos?

Answer 18

Pingos are a dome created on the ground due to the upward expansion of ice. There are two types of pingos.

1. open system: The growth of the ice core is hydraulic.
2. closed system: They are hydrostatic, they from due to the downward growth of permafrost.

Question 19

What are the 3 factors that effect periglacial weathering?

Answer 19

1. Climate- Temperature fluctuations increase frost weathering.
2. Moisture- rock disintegration is more effective in wet climates.
3. Rock structure- Rocks response to weathering effects landforms.

Question 20

What are the 4 types of weathering landforms?

Answer 20

1. Talus slopes
2. Protalus slopes
3. Blockfields
4. Trim line

Question 21

What is a talus slope?

Answer 21

A steep slope that debris piles up on to create an angle of response. The slope readjusts to new debris and movement.

Question 22

What is a portals slope?

Answer 22

An accumulation of debris that falls down a steep slope. can also be formed by landslides or avalanche.

Question 23

What is a blockfield?

Answer 23

Freeze thaw weathering breaks up the top layer of rock, covering the underlying rock with jagged, angular boulders.

Question 24

What is trim line?

Answer 24

A line on the side of a valley formed by glacier. The line marks the most recent highest extent of the glacier.