glacial landforms changing w climate + fluvio landforms

Question 1

how are fluvial glacial landforms created?

Answer 1

produced by meltwater from glaciers

Question 2

how is this environment created in the immediate wake of a glacial period?

Answer 2

ablation begins to dominate the glacial system and glacier melts and retreats as long term climatic conditions alter

Question 3

what is the importance of glacial meltwater?

Answer 3

1. melting snow helps to enlarge the shallow nivation hollows that eventually become corries
2. helps to lubricate the base of the glacier
3. transports moraine beneath a glacier, tools for erosion
4. if it refreezes, it can bind the base to broken fragments
5. often forms river- both below and atop
6. erode channels and form distinctive depositional features

Question 4

what is outwash?

Answer 4

the distinctive sediment only deposited by glacial meltwater

Question 5

how is outwash different to till?

Answer 5

1. smaller- meltwater streams have less energy so carry finer material
2. smooth and rounded- by contact with water and by attrition
3. sorted- horizontally with largest material further up valley
4. stratified- vertically with distinct seasonal and annul layers

Question 6

what are Kames?

Answer 6

hill or hummock composed of stratified sand and gravel laid down by glacial meltwater

Question 7

what is the sediment of a kame like?

Answer 7

the sediment consists of sand and gravels and builds up into mounds as the ice melts and more sediment is deposited on top of old debris

Question 8

what will often happen to Kames?

Answer 8

they will collapse when the ice melts back and leaves mounds unsupported

Question 9

What are Kame terraces and how are they formed?

Answer 9

differential specific heat capacity of the valley and glacier, leading to supraglacial streams which deposit material along the valley side

Question 10

what happens to kame terraces in the summer

Answer 10

when the walls warm up in the summer the warm rock helps to melt the ice nearest to it, forming a long depression or trough along which meltwater flows

Question 11

why are deposits sorted in kame terraces and how does this make a kame identifiable?

Answer 11

because they are transported by water which allows them to be distinguished from lateral moraine deposits which exhibit no sorting

Question 12

what are Eskers?

Answer 12

long, sinuous ridges composed stratified of sand and gravel laid down by glacial meltwater

Question 13

how are Eskers formed?

Answer 13

1. material is deposited in subglacial tunnels as the supply of meltwater decreases (may carry huge amounts of debris under pressure in confined tunnels at the base of the glacier)
2. the snout retreats, the point of deposition will gradually move backwards
3. leaving behind a long sinuous ridge composed of stratified sand and gravel

Question 14

What is an outwash plain?

Answer 14

an extensive, gently sloping area of sand and gravel that form in front of a glacier

Question 15

what is an outwash plain a result of?

Answer 15

result of the outwash of sediment carried by meltwater streams and rivers losing their energy

Question 16

what is the composition of outwash plain?

Answer 16

coarse material which is found near to the glacier, and finer clay, which is carried across the plain before being deposited

Question 17

how are outwash plains drained?

Answer 17

typically drained by braided streams, river channels subdivided by numerous isles and channels

Question 18

how are braided channels formed?

Answer 18

1. begin with a mid-channel bar which grows downstream, discharge decreases after a flood and the coarsest particles are deposited
2. as discharge decreases finer material is then added to the bar
3. when exposed channel bars are stabilised by vegetation and become more permanent features

Question 19

what happens to unvegetated bars?

Answer 19

they are unstable and often move, form and reform with successive flood

Question 20

named example and dimensions of an esker

Answer 20

trim esker near Dublin
14.5km long, 4-15m tall

Question 21

named example and dimensions of Kame

Answer 21

yorkshire dales , 2km long 2m high

Question 22

when is a glacial fluvio period?

Answer 22

exist as a result of climate change at the end of glacial periods
during inter glacial lasting 10,000-15,000

Question 23

how are glacial fluvio landforms formed?

Answer 23

produced by meltwater released during deglaciation

Question 24

how is a delta kame formed?

Answer 24

en-glacial streams losing energy at the
base of a glacier or a supraglacial stream
losing energy as it enters a ice marginal static lake
deposits material as it loses energy
eg East Lothian, Scotland

Question 25

discharge in meltwater rivers

Answer 25

have high discharge in the summer months and lower in winter
eg glacier d’Argentière
discharge is 0.1-1.5 cumecs in winter
but 10-11 cumecs in summer

Question 26

how does volcanic activity impact discharge levels?

Answer 26

jokulhaulps - volcanic activity below a glaciers causing sudden melting
eg after 2010 eyjafjallajokul discharge was 2500 cumecs

Question 27

what do beaded eskers show?

Answer 27

larger beads imply slower rate of retreat

Question 28

modification of glacio fluvial landforms

Answer 28

repeated advance and retreat of glaciers erode and change shape of landforms
colonisation by vegetation - increased chemical weathering eg chelation
temperatures rise = more accumulation of outwash material in pro glacial zone
kames and eskers exposed in greater length during retreat
eg Sòlheimajökull retreating at 100m/year, a pro-glacial lake may form at snout