Geography glacial erosion and deposition

  1. how was a u shaped valley formed
  2. a v shaped valley is occupied by a glacier
    • glacier moves downhill by gravity
    • plucking and abrasion deepen widen and straighten the valley
    • after glaciation a steep-sided flat bottomed valley is left
    • if the valley had inter locking spurs they will have been
    • truncated
    • often a mis-fit stream or ribbon lake is found on the valley
    • floor
    • Image Upload 2Image Upload 4Image Upload 6
  3. how was a corrie formed
    • snow gathers in holoow on north facing slope
    • glacier moves downhill by gravity
    • plucking steepens the back wall
    • abrasion deepens the hollow
    • rotational movement leads to rocklip where erosive power is least
    • after glaciation an arm chair shapped hollow is left, often with a corrie lochan or tarn
    • frost shattering continues on backwall casuing scree
    • Image Upload 8
  4. how is an arete formed
    • two corrie seroding back to back
    • plucking narrows the distance between two backwalls
    • after glaciation, a narrow knife edge ridge seperates the two corries
    • this is known as an arete
  5. how is a pyramidal peak formed
    • three or more corries eroding back to back on the same mountain
    • plucking narrows the distance between the back walls
    • after glaciation a pointed, horn shaped peak is left
    • frost shateering continues on summit
    • Image Upload 10
  6. how is a hanging valley formed
    • glacier moves down a main v shaped valley
    • erodes by pucking and abrasion and the valley gets deeper and wider
    • a smaller glacier erodes a tributery valley
    • it is eroded less deeply
    • after glaciation the smaller valley is higgher than the main valley
    • a waterfall is often formed
  7. how is terminal moraine formed
    • glacier picks up moraine and transports it
    • glacier melts and the moraine is deposited at the snout of the glacier
    • a ridge of angular, unsorted rocks is left
    • the ridge marks the furthest point the glacier reached
  8. how is an outwash plain formed
    formed when sorted sand and gravel is washed out of the glacier by meltwater (water melting from the glacier) and deposited as a large flat area in front of the terminal moraine
  9. how are drumlins formed
    • drumlins are egg shaped mounds formed when the glacier moulds till beneath it, to form streamlined moulds
    • they have a steep blunt end (stoss) and a gently sloping end (lee)
    • the ice moved towards the pointed end (lee)
    • Image Upload 12
  10. how is an esker formed
    Eskers are formed by melt water from the glacier

    Meltwater flows in tunnels beneath the glacier

    • Stream carries sand and gravel and when this is deposited it
    • fills up the tunnels

    • When ice melts a long meandering ridge is left in the shape
    • of a tunnel
Card Set
Geography glacial erosion and deposition
formation of glacial erosion and deposition