❄️ glaciation sg2a

Question 1

what are the 5 geomorphic processes

Answer 1

weathering
mass movement
erosion
transportation
deposition

Question 2

what are the 3 types of weathering

Answer 2

physical
chemical
biological

Question 3

what are the 3 main mass movements

Answer 3

slumps
slides
rockfalls

Question 4

what are the 2 main types of glacial erosion

Answer 4

abrasion: when debris in glacier scours surface, wearing it away
plucking: when meltwater gets in cracks in surface and freezes and becomes attached to glacier, pulling away pieces of rock

Question 5

supraglacial debris

Answer 5

carried on surface

Question 6

englacial debris

Answer 6

carried within the glacier

Question 7

subglacial debris

Answer 7

transported at the base of the glacier

Question 8

glacial till

Answer 8

material carried directly by the ice
- angular
- unsorted
- no orientation
- not stratified

Question 9

glacial fluvial material

Answer 9

deposited by meltwater
- quite smooth
- sorted
- orientated same direction
- not stratified

Question 10

what is a corrie

Answer 10

circular steep sided hollow high up on a mountain side. armchair shaped hollow

Question 11

how does ftw create a corrie

Answer 11

• takes place on back wall creating supraglacial debris
• takes place in bergschrund crevasse
• erodes base of glacier

Question 12

how does rotational movement form a corrie

Answer 12

glacier moves under its own weight creating rotational movement which erodes base of glacier and creates armchair shape

Question 13

how does pressure create a corrie

Answer 13

pressure on back wall = erosion

Question 14

how does ftw form a corrie in an interglacial period

Answer 14

• ftw continues on steep slopes = rockfalls into tarn
• can create scree slopes at base of back wall

Question 15

how does pressure release weathering form a corrie in an interglacial period

Answer 15

• takes place on base so hollow will deepen further

Question 16

how does biological weathering modify a corrie in interglacial period

Answer 16

vegetation may grow due to warmer temps = roofs grow into the cracks

Question 17

what flows of energy form a corrie

Answer 17

• height and weight determines potential energy & PMP
• when PMP is reached thermal energy is created at base = meltwater = basal sliding = kinetic energy
• as glacier leaves hollow and thins, potential energy is reduced = less kinetic energy
• rocks have potential energy. when’s gravity overcomes friction = FTW

Question 18

what flows of materials form a corrie

Answer 18

• origin: FTW=debris created which would fall down crevice
• movement: rotational slip = abrasion by the materials
• deposition: some is deposited building lip
• modification: post glaciation = FTW continues = back wall steeper

Question 19

what is an arête

Answer 19

knife edge between 2 corries

Question 20

how do arêtes form

Answer 20

• snow falls in hollows and create corries
• as the 2 corries share a backwall, as they erode and back steeper an arête is formed

Question 21

what is a pyramidal peak

Answer 21

isolated point caused by erosion of 3+ corries into same mountain

Question 22

how does a pyramidial peak form

Answer 22

same as arête but 3 backwall’s eroding into eachother

Question 23

what is a glacial trough

Answer 23

a valley that a glacier runs through

Question 24

how does a glacial trough form

Answer 24

• begins as v shaped valley with a stream flowing through it
• as glacial period begins, snow begins to fall into it and through diagnosis, a glacier is formed
• there may often be a tributary glacier from higher up
• FTW on the high mountains creates sub glacial debris
• this erodes sides and bottom of valley creating u shaped valley
• post glacial: tributary glacier turns into a hanging valley which often has a waterfall, often a misfit stream flowing through middle

Question 25

what is a truncated spur

Answer 25

where a glacier has eroded through a interlocking spur

Question 26

what is a hanging valley

Answer 26

tributary glacier hanging above main glacier (waterfall post glacial)

Question 27

what is a misfit stream

Answer 27

river in an interglacial trough that almost seems out of place

Question 28

what is a ribbon lake

Answer 28

forms in rock basin on floor of interglacial trough

Question 29

what flows of energy create a glacial trough

Answer 29

• height and mass determine potential energy
• mass determines PMP
• PMP reached = thermal energy at base = meltwater = basal sliding = kinetic energy
• tributary glaciers add mass = potential energy increased
• interglacial period = warmer = more thermal energy = glacier melts

Question 30

what flows of material create a glacial trough

Answer 30

origin: FTW = rockfall & plucked debris from valley floor
movement: basal sliding causes abrasion with deepens & steepens
deposition: rock basin may be dammed by terminal moraine
modification: FTW may create scree slopes

Question 31

what is a roche moutonnee

Answer 31

a rounded mass of rock smoothed and striated by ice that has flowed over it

Question 32

how is a roche mountonnee formed

Answer 32

• on stoss end: PMP is reached as ice approaches rock = ice melts = basal sliding & some abrasion
• on lee end: pressure release = ice refreezes = FTW & plucking of material which creates jagged edge

Question 33

what does a roche mountonnee look like in an interglacial period

Answer 33

• smooth, rounded stoss end due to abrasion & some striation marks
• steep and jagged lee end due to FTW & plucking

Question 34

how have flows of energy formed a roche mountonnee

Answer 34

stoss end: thermal energy due to pressure melting & basal sliding = thermal energy
lee end: pressure reduced = thermal energy lost so water refreezes

Question 35

how have flows of material formed a roche mountonnee

Answer 35

origin: subglacial material FTW & plucking up stream
movement: moves due to regelation = abrasion, FTW & plucking on lee end