glacial systems

Question 1

over what time period did the Pleistocene last

Answer 1

1.8 million years ago until 11700 years ago

Question 2

what was the name of the ice sheets which covered Briton in the last glacial maximum

Answer 2

Scandinavian ice sheets

Question 3

what are the 4 types of glacial environment

Answer 3

polar - areas of permanent ice , Antarctica and Greenland

periglacial - on the edge of permanent ice . permanently frozen ground , Canada , Alaska

alpine - mountain areas- European alps

glacial - found in the edges of ice sheets and in mountainous regions , Himalayas and andes

Question 4

what happens in the zone of accumulation

Answer 4

inputs exceed outputs

Question 5

what are factors for the accumulation zone

Answer 5

higher altitude means increased snow fall

new snow means albedo effect which keeps it cooler reflecting the sunlight

strong winds means snow is blown into hollows and basins - accumulating

Question 6

what is the albedo effect

Answer 6

ice and snow surfaced reflect more light keeping them cooler

Question 7

what are the 3 factors keeping glaciers cold

Answer 7

latitude

albedo effect

altitude

Question 8

what is the main input in the accumulation zone

Answer 8

snow.

turns to compacted ice over years

avalanches and mountain slides can be inputs

Question 9

what happens in the ablation zone and what are its factors

Answer 9

output exceed inputs

lower altitude means less snowfall and higher temperatures

melting

sublimation

evaporation

calving

Question 10

what are the 2 zones within a glacier

Answer 10

accumulation zone

ablation zone

Question 11

what are the outputs in the ablation zone

Answer 11

calving

evaporation

sublimation

melting

Question 12

what is the equilibrium line

Answer 12

the boundary where gains and loses are balanced

Question 13

what is the glacial budget

Answer 13

considers the balance between inputs and outputs

Question 14

what happens to the glaciers mass balance across a year

Answer 14

mass balance varies across a year

in summer ablation will be at its highest due to rapid melting of ice

in winter high snowfall and limited melting results in accumulation being higher than ablation

Question 15

what are the characteristics of a warm based glacier

Answer 15

found at lower latitudes often in alpine environments

water present throughout the glacier which helps with movement

move much more than cold based glaciers . 20-200m per year

Question 16

how far do cold base glaciers move a year

Answer 16

cms Per year

Question 17

how far do warm based glaciers move per year

Answer 17

20-200 m

they erode and move large amounts of material

Question 18

cold base glacier characteristics

Answer 18

found in polar regions in the arctic and Antartica

glacial ice remains frozen to the bedrock so limited movement

movement is cms per year

Question 19

which glaciers can slide down mountains due to basal siding

Answer 19

warm based glaciers

Question 20

what is basal sliding

Answer 20

siding of a glacier over bedrock due to meltwater at glaciers base

Question 21

why does basal sliding occur

Answer 21

small obstacles create pressure points

increase of pressure causes melting - pressure melting point is reached

melting allows glacier to slide over the obstacle

meltwater refreezes on the downside of the obstacle and pressure reduces

this melting and freezing is called REGELATION

Question 22

what is regelation

Answer 22

the melting and freezing which occurs in basal sliding

Question 23

how do cold based glaciers move

Answer 23

internal deformation

Question 24

which glaciers does internal deformation take place

Answer 24

warm and cold based glaciers

Question 25

how big it the rate of movement by internal deformation

Answer 25

1-2 cm per day

Question 26

what is intergranular movement

Answer 26

individual ice crystals slipping and sliding over one another ice crystals within a glacier tend to orientate themselves in a direction of ice movements - means they can slide past each other

Question 27

what is intragranular movement

Answer 27

individual ice crystals becoming deformed or fractured because of the stress from the glaciers mass from gravity . ice deforms and moves downhill due to poverty

Question 28

3 characteristics of extensional flow

Answer 28

slope steepens velocity increases ice thins

Question 29

3 characteristics of compressional flow

Answer 29

slope decreases velocity decreases ice thickens - erosion

Question 30

what are the different factors affecting ice movement

Answer 30

temperature of ice - in some places the temperature is so cold the ice freezes to the bedrock which causes slower movement gravity - downhill force causing the ice to move . steeper gradient means greater pull meltwater - lubricants the base of the ice enabling it to slide downhill friction - mass of ice - heavier the ice the more potential energy needed . more force needed

Question 31

what are geomorphological processes

Answer 31

natural process which shape the earths landscape

Question 32

what is weathering

Answer 32

breakdown or disintegration of rock in its original position or just below the ground surface

Question 33

what is the process of frost shattering

Answer 33

water seeps into cracks and freezes when reaches bellow 0 C - it expands by 9% in volume this enlarges cracks and pores overtime cracks enlarge and chunks of rocks break away and pile up as scree

Question 34

what is nivation and where does it take place

Answer 34

nivation makes hollows deeper by freezing and thawing snow gets into hollows and increases the size of the hollows every time ice freezes it expands and breaks bits of rocks when the snow melts the meltwater carries broken rock and debris away eventually the rock becomes deeper and wider

Question 35

what are the 3 glacial processes

Answer 35

transportation erosion deposition

Question 36

what are the 2 main forms of erosional processes

Answer 36

abrasion plucking

Question 37

what is abrasion

Answer 37

the sandpapering affect of ice as it grinds over the landscape

Question 38

where do the scratches in the bedrock come from and why are they useful what are they called ?

Answer 38

come from large rocks carried beneath the ice which scrape on the rocks they are called striations useful for studying the direction of ice flow in the post glacial environments

Question 39

what is plucking

Answer 39

meltwater freezes the bedrock to the base of the glacier. any loose rocks will be plucked away by the glacier.

Question 40

what landform is caused by plucking and abrasion and basal sliding

Answer 40

roche moutonnée

Question 41

how is abrasion shown in a Roche moutonnee

Answer 41

steep sided edge formed by abrasion with evidence of striations on the surface

Question 42

roche moutonnée and basal sliding

Answer 42

ice slides over obstacle due to pressure melting point and melting at the base (basal sliding )

Question 43

where is plucking in a Roche moutonnee

Answer 43

jagged downvalley ice would refreeze on the down valley of the obstacle then move, plucking away the rock

Question 44

what are the 3 types of glacial transportation

Answer 44

supraglacial englacial subglacial

Question 45

what supraglacial

Answer 45

weathered material carried on top of the ice

Question 46

englacial

Answer 46

once supraglacial material , now buried by snowfall and carried in the ice

Question 47

subglacial

Answer 47

material carried beneath the ice , dragged by the overlying glacier