glacial landforms

• u shaped valleys


  glacier moves through

  flat bottom

  high side walls
• hanging valley


  a tributary valley that enters a glacial trough at a considerable height above its floor

  stops when they meet

  ice melts
• misfits streams


  river in a glacial valley

  not meant to be there
• corrie example


  Cwm Idwal in Wales

  
• corrie features


  steep back wall

  armchair depression

  corrie lip

  moraine

  bergschrund
• corrie processes


  plucking on back wall

  abrasion of bedrock

  rotational flow in the middle
• ice wedge polygon example

  north of Alaska

  
• ice wedge polygon features


  same pattern as stone polygon on top

  trough and a rim
• ice wedge polygon process

  - cold temps form cracks in ground surface

  - fill with meltwater during warmer periods

  - water freezes and expands, crack widens

  - over time large cracks open up
• ice wedge polygon after glaciation?

  crack may become filled with finer sediment
• what is scree?


  broken rocks that lay upon a steep slope

  usually on valley sides

  - angular > weathered by freeze thaw and periglacial processes
• what is felsenmeer?


  large areas of broken rocks

  bottom of the valley

  - angular > weathered by freeze thaw and periglacial processes
• kettle hole example


  Sunfish lake

  
• kettle hole features


  rounded
• kettle hole processes


  - blocks of ice that are separated from the main glacier

  - cold conditions, isolated ice blocks become partially buried in meltwater sediments

  - ice blocks melt + leave kettle holes
• pingo example


  Tuktoyaktuk, Canada

  
• pingo features


  rounded ice cored hills

  huge collection of water in soil

  must be v wet and cold

  - up to 90m in height

  - 800m in diameter
• pingo processes


  - water trapped within the ground freezes, expands and pushes the land above it upwards

  - hyrdrolaccolith (underground pool of water) perennial ice formations that melt and reform seasonally

  - frost heave
• what is an ognip?

  a collapsed pingo
• closed system ognip?


  - underneath a body of water (lake or pond)

  - water on top

  - lots of surface water ie moat
• open system ognip?


  - formed in areas with lots of groundwater

  - bottom of valley
• solifluction lobes features? (periglacial)

  tongue shaped

  series of lobes in a step-like feature

  bedrock underneath
• solifluction lobes process


  - meltwater infiltrates into soil and saturates it quickly as lower layer is permanently frozen

  - saturation reduces friction between particles within soil

  - saturated soil flows downhill and rests

  - large stones pushed upwards and to front creating a stone bank
• solifluction lobe

  
• patterned ground, stone polygons and stone striping

  - result of frost heave

  - hexagonal shape created

  - on slopes exceeding 60 degrees hill is too steep for stones to rest on and stone stripes are formed
• stone polygons example


  Glen Rosa, Scotland

  1.5 m in diameter

  - valley floor

  
• stone polygon features


  - sorted stone (large on outside, rolled down > small on top)

  - deflated or dipped area in between stones

  - hexagon
• stone polygon processes


  - result of frost heave

  - large circles of stones are formed as temp fluctuates (o and -4)
• Kame terrace example


  Glen Rosa

  - thickness up to 100m

  - side of the glacial valley

  
• kame terrace features


  mounds of sediment (irregular shape)

  sands & gravel (small material)

  sorted deposits (transported by meltwater)

  flat, long benches

  sub angular

  sorted

  stratified

  unconsolidated
• kame terrace processes


  - deposition > sediment along the front of a slowly melting or stationary glacier

  - formed by actions of meltwater streams that flow along the sides of the ice, trapped against it by the valley walls
• nivation hollow example


  Glen Rosa

  - found everywhere

  
• nivation hollow features


  long established snow patches

  debris
• nivation hollow processes


  - physical weathering

  - frost shattering

  - prolong action of freeze thaw

  - debris is moved by meltwater flowing
• esker example


  glen rosa

  5-50m in height

  500m in width

  
• esker features


  - sinuous, serpentine, meandering + fluvial mound of sediment

  - sub rounded

  sorted

  stratified

  unconsolidated
• esker processes


  deposition

  river flowing (turbulent) in a glacier

  glacier retreats sediments get deposited in a mound
• medial moraine example


  glen rosa

  100-1000m

  found between 2 glaciers

  
• medial moraine features


  angular rocks

  aligned in the direction of flow

  unsorted

  unstratified

  unconsolidated

  pile of rocks

  pyramidal shape
• medial moraine processes


  plucking + freeze thaw

  (no pattern) deposition