fluvioglacial landforms

Question 1

eskers

Answer 1

• long winding, ridges of sand and gravel that run in the same direction as the glacier
• they are deposited by meltwater streams flowing in subglacial tunnels
• when the glacier retreats and the stream dries up, the load remains as the esker is made of sorted and stratified materials
• eskers show where glacial tunnels used to be and can be several hundreds of km in lenfth and 50m high

Question 2

kames

Answer 2

stratified mounds of sorted sand and gravel found on the valley floor near the snout of the glacier
- supraglacial meltwater streams collect in depressuons in the ice and lose velocity
- this reduces their carrying capacity , so debris is depositied in layers. when the ice metls, the debris is dumped on the valely floor.

Question 3

kame terraces

Answer 3

piles of deposits left agained the valley walls
- thet are formed by meltwater streams that run betweeen the glacier and the valley sides
- they look like lateral moraine, but they are sorted layers

Question 4

meltwater channels

Answer 4

• meltwater strams can form troughs in the landscape called meltwater channels
• melt water streams ahve a lot of errosive power, so the meltwater channels they prodeuce are deep and wide
• when the glacier has retreated, shallow streams run through the deep meltwayter channels left behind.
• if the meltwater has hugh sediment load, braided streams may form

Question 5

sandurs/outwash plain

Answer 5

it is a layer of gravel, sand and clay that forms in front of where the snout of the glacier used to be

• meltwater flowes out of the glacier, and carries the sediment with it
• sediment is sorted into layers
  1) gravel gets droped firstbecause it is the heaviest abd forms at the bottom of the plain
  2) clay is dropped last and gets carried the furthest away from the snout because it is the lightest- forms the top layer of the outwashplain

Question 6

kettle holes aka kettle hole lakes

Answer 6

• the retreating glacier can leave behind blocks of ice on a sandur
  -as these blocks of ice melt, they will reveal individual depressions and any overlying sediment whill collape into the deression

Question 7

proglacial lakes

Answer 7

• form infornt of glacies when the terminal moraine dams the flow of meltwater streams
• as meltwater streams flow into a proglacial lake, they slow down and deposite their sediment on the ice (this is called delta)
• each layer of sediment is known as a varve