geo

• Long shore drift

  Due to prevailing winds, waves tend to approach a beach at roughly a 45-degree angle, the swash carries the material (sand, shingle) and travels up the beach in the same direction as the breaking wave. The water then returns down the beach. This is called backwash. Due to gravity the backwash and any material it is carrying tends to go straight down the beach. The result is that material is transported along the beach in a zig-zag movement. This movement of beach material is longshore drift. The prevailing winds cause longshore drift to move in a certain direction.
• bar

  first four of spit. Due to the absence of a river to carry materials out to sea, the spit can grow right across the bay to form a bar. A bar may also form where a sand bank develops off shore but waves slowly move the sand band towards the coast until it joins the mainland. A lagoon is normally found on the landward side of the bar. Over time this will be filled due to the disposition to form a salt marsh.
• Tombolo

  First four of spit. The spit will continue to grow outwards and may connect to an island providing a link to the mainland. This is called a tombolo
• pyramidal peak

  Corrie formation. When this happens on all sides of the mountain it means that a number of corries form back to back. As these corries get deeper through erosion & aretes form between them a sharp top of the mountain is left called a pyramidal peak.
• Arete

  Corrie formation. Two corries form a back to back this leaves a sharp edge running between them called an arete.
• Snow accumulation in north facing hollows

  • Less sun
• Snow build up

  1. Increased weight

  2. Squeezes air out of snow

  3. Forming firn (neve)

  4. Forming glacial ice
• Glacier

  Formed, moves downhill due to gravity
• Abrasion

  1. Angular rock embedded in ice

  2. Grinds the hollow

  3. Deepening it
• Plucking

  1. Ice freezes on to bedrock

  2. Pulling loose rocks away from the backwall

  3. Leaving it jagged and steep

  4. Material may aid abrasion later
• Rotational sliding

  1. Weight of glacier pushes down

  2. Over deepening the hollow
• Freeze-thaw weathering

  1. Steepening the back wall

  2. Scree slopes may form
• Friction

  1. Causes ice to slow down at the front edge

  2. Allowing a rock lip to form
• Corrie

  • Can be filled in by rain water
  • Forming a tarn/lochan
• Example of a corrie

  • Brown Cove
• Moraine

  Material transported by a glacier
• Formation of moraine

  1. Freeze thaw and plucking remove material from the sides of the valley

  2. Material falls in front of the glacier

  3. Glacier advances and "bulldozes" rock and soil in front of it - gathered from ground and surface moraine
• Terminal moraine

  Marks the furthest point that a glacier reaches
• Terminal moraine

  • Forms a jumbled mass of unsorted material that stretches across the valley floor
  • Can form a natural dam, creating a moraine dammed lake after the ice has retreated
• Drumlin

  Elongated hills made up of unsorted glacial deposits
• Formation of drumlins

  1. Melting ice deposits large amounts of moraine (till) under the ice

  2. Glacier becomes overloaded with sediment and deposits it

  3. Small obstacle on the ground acts as a trigger point and till/boulder clay can build up around it
• Drumlin

  • Steep 'stoss' slope faces up-valley
  • More gently-sloping 'lee' slope faces down-valley
  • May be reshaped by further ice movements after being originally deposited
  • If the ice starts to advance again the glacier erodes the moraine into streamlined mounds
• Drumlins

  • Found in swarms or in a 'basket of eggs' topography
• Esker

  Meandering ridge where melt water streams form under the ice and carve tunnels through the glacier (through melting)
• Formation of eskers

  1. Melt water streams transport moraine through the glacier

  2. Melt water streams lose energy and deposit their load

  3. Tunnel fills up
• Esker deposits

  • Steep sided ridges of sorted material (e.g. sand and gravel)
  • Fluvio glacial - sorted by size, dropping larger stones at the base and smaller deposits at the top
  • Deposited stones are often rounded as they have been shaped by the flowing water
• As the glacier retreats, the esker deposits are left in the shape of the melt water tunnel
• Formation of a U-shaped valley

  1. Snow accumulates over time in a north/north-east facing hollow

  2. Snow compacts to form nevee

  3. Nevee compacts to form ice

  4. During periods of glaciation, the glacier advances to fill the V-shaped valley

  5. Glacier has greater power to erode than a river due to its size

  6. Glacier carves its own route due to gravity

  7. Glacier 'bulldozes' its way through the valley, removing interlocking spurs to form truncated spurs

  8. Glacier plucks rocks from the sides, making the sides steeper

  9. Rocks trapped in the ice abrade the base of the valley, making it deeper

  10. Freeze-thaw action produces scree that falls into the glacier, further abrading the base

  11. When the temperature increases, the glacier melts and retreats

  12. Erratic are deposited and scree falls into the valley, creating a U-shaped valley

  13. The river returns as a misfit stream
• Snow accumulates over time in a north/north-east facing hollow
• Snow compacts to form nevee, which then compacts to form ice
• During periods of glaciation, the glacier advances to fill the V-shaped valley
• The glacier has greater power to erode than a river due to its sheer size
• The glacier carves its own route as it moves due to gravity
• The glacier 'bulldozes' its way through the valley, removing interlocking spurs to form truncated spurs
• The glacier plucks rocks from the sides, making the sides steeper
• Rocks trapped in the ice act like sandpaper to abrade the base of the valley, making it deeper
• Freeze-thaw action produces scree that falls into the glacier, further abrading the base
• When the temperature increases, the glacier melts and retreats
• Erratic are deposited and scree falls into the valley, creating a U-shaped valley
• The river returns as a misfit stream