Glaciers

Question 1

How much of the earths water is found in glaciers?

Answer 1

2.15%

Question 2

Define glacier

Answer 2

a thick mass of ice that accumulates naturally over hundreds or even thousands of years, and deforms (flows) under its weight

Question 3

What are the two (three) necessary criteria to form glaciers?

Answer 3

1) precipitation of snow
2) snow falls exceed summer falls

8/*annual average temperature must therefore be below zero

Question 4

Glacial ice results from accumulation of packing snow, what are the steps of compaction of the snow?

Answer 4

1) snow
2) granular snow
3) firn
4) glacial ice

*air is gradually forced out and pore space is reduced as the snow gets more compact

Question 5

Where do glaciers develop?

Answer 5

-areas of high altitude (mountainous regions)

-areas of high latitude (polar regions)

Question 6

What is the snowline?

Answer 6

the elevation above which snow does not completely melt

Question 7

What are the two main types of glaciers?

Answer 7

1) ice sheets (unconfined)
2) alpine glaciers (confined)

Question 8

Name the parts of alpine glaciers (top to bottom)

Answer 8

1) zone of accumulation (where more snow falls than melts)

———-equilibrium line———–
(boundary between two zones)

2) zone of ablation (where more melting then snowing happens)

—————terminus—————
(the lowest end of a glacier)

3) outwash plain (flat land formed by meltwater streams)

Question 9

What is the glacial budget?

Answer 9

the balance (or lack thereof) between the gain and loss of ice

Question 10

What does it mean when the glacial budget is negative- a negative budget?

Answer 10

-when ablation exceeds accumulation
-results in the retreat of the terminus

Question 11

What does it mean when the glacial budget is positive- a positive budget?

Answer 11

-when accumulation exceeds ablation
-results in the advancement of the terminus

Question 12

What does it mean when the glacial budget is neutral- a neutral budget?

Answer 12

-when accumulation and ablation come into balance
-terminus remains relatively stationary

Question 13

What are the two ways glaciers erode the land?

Answer 13

1) abrasion
2) plucking

Question 14

What does glacial erosion form?

Answer 14

1) glacial structures (striations, grooves, roche moutonnée)
2) glacial landscape (alpine regions)
3) glacial deposits

Question 15

what are striations?

Answer 15

parallel groves/ scratches that can appear on various surfaces, due to a variety of reasons such as glacial movement

Question 16

What are glacial grooves?

Answer 16

long, linear troughs carved into bedrock by the glacial movement

Question 17

What are roches moutonnée

Answer 17

asymmetrical bedrock hills formed by glacial erosion

Question 18

What is a V- shaped valley?

Answer 18

formed by glacial river/ steam that over time builds a narrow crevasse that water flows down

Question 19

What is a U- shaped valley?

Answer 19

-When glaciers move through pre-existing V-shaped valleys
-U-shape with steep, straight sides and a flat or rounded bottom

Question 20

What is a glacial cirque?

Answer 20

These are bowl-shaped depressions at the head of a glacial valley, formed by the erosive action of glaciers

Question 21

What are glacial horns

Answer 21

When multiple arêtes converge, they can form a steep, pyramid-shaped peak called a horn
*glaciers erode a mountain peak from three or more sides, creating a sharp, pointed peak.

Question 22

What are glacial arrets?

Answer 22

These are sharp, jagged ridges formed between two or more cirques that have eroded back to back
*two glaciers erode a mountain ridge, leaving a sharp, jagged crest between them

Question 23

What is a Fjord?

Answer 23

A fjord is a flooded U-shaped valley- filled with sea water

Question 24

What is a hanging valley?

Answer 24

a smaller side valley left ‘hanging’ above the main U-shaped valley. formed by a tributary glacier
-waterfalls can often be seen

Question 25

What are glacial deposits?

Answer 25

-glaciers pick up particles and debris of all shapes and sizes and they transport them as they move

Question 26

How can the particles being transported by glaciers be deposited?

Answer 26

-directly by glacier -glacial meltwater

Question 27

Name other types of glacial deposits

Answer 27

outwash plain, moraines, eskers, drumlines, kettles, kames, erratic block

Question 28

end moraine vs ground moraine

Answer 28

- ground moraine: forms as a layer of till deposited beneath a glacier as it melts, when glacial ablation exceeds accumulation -end moraine: forms at the edge of a glacier when the glacier's advance stops and the glacier's budget is at equilibrium

Question 29

What is an esker?

Answer 29

Long, winding ridges of sediment deposited by meltwater streams flowing within or beneath a glacier

Question 30

what is a lateral moraine?

Answer 30

lateral moraines form along the sides of a glacier

Question 31

What is a drumline?

Answer 31

They are elongated hills composed of glacial till, shaped by the flow of ice

Question 32

What are kames?

Answer 32

they are hills or mounds of sediment deposited by meltwater streams flowing out of a glacier

Question 33

What are kettles?

Answer 33

they are depressions or holes in an outwash plain formed by the melting of blocks of ice left behind by retreating glaciers, which become buried in sediment

Question 34

what is an erratic block?

Answer 34

they are large boulders transported and deposited by glaciers in locations that are geologically unusual for that type of rock