Glaciation Flashcards
plucking
glacial erosion
- glacial ice melts due to friction as it moves over obstacle
- it refreezes due to pressure from the ice above
- it refreezes in the cracks in the rock and when the glacier moves forward it rips the rock from the ground
abrasion
glacial erosion
- rocks stuck to the base of the glacier scour and scrape the land below like sandpaper
- striations are scratches formed as a result of abrasion
freeze thaw weathering
glacial erosion
- water collects in the cracks of a rock and freezes, expanding by 9%, exerting pressure on the surrounding rock, deepening the cracks
- the water melts running deeper into the rock and the process repeats
- this repeated freezing and thawing eventually breaks apart the rock into smaller fragments
formation of a corrie
summary
- snow collects in north facing hollows which receive less sunlight meaning it lies for longer
- layers of snow compact into glacial ice called nevee or firn
- the mass of ice increases and weight and gravity causes rotary action called rotational slip
- plucking occurs
- abrasion occurs
- the bergschrund - a gap at the back of the glacier - allows meltwater and rock fragments into the glacier increasing erosive power, it also allows frost shattering to occur
- friction at the front of the glacier as it rotates out of the hollw decreases erosive power making a lip
- ice melts to form corrie and tarn
red tarn, lake disrtict
formation of a pyramidal peak
summary
- corrie formation
- when three or more corries form back to back a pyramidal peak is formed
helvellyn, lake district
formation of a u-shaped valley
summary
- glacier forms - snow builds up and compacts into nevee/firn
- glacier flows down existing v-shaped valley
- plucking and abrasion steepen, deepen and straighten the valley
- interlocking spurs become truncated spurs
- tributary valleys form hanging valleys
barrowdale, lake district
formation of a ribbon loch
summary
- formation of u-shaped valley
- the glacier reaches an area where the rock is softer and the glacier hollows out that area of the valley floor much deeper than the rest
- after the ice has melted the hollow is filled with water from a misfit stream to form a ribbon loch
thirlmere, lake district
alternatively the glaciers power can increase during colder periods creating a deeper section
terminal moraine
glacial depositional features
- ridge across the valley made of unsorted glacial deposits
- formation: glacier pushes sediments as it moves, when it reaches lower altiudes the temperatures rise, the glacier deposits morraine as it melts
- marks the furthest point the glacier reached
drumlin
glacial depositional features
- elongated hill made of unsorted glacial deposits
- formation: glacier becomes overloaded with sediments so deposits it steamlining it as it goes over it; when the ice melts slightly the moraine is deposited and streamlined; when the glacier reaches a small obsticle this acts as a trigger point for deposit
- basket of eggs topography
stoss = steep end; lee= flatter end
eskers
glacial depositional features
- meandering ridges formed by meltwater streams in or underneath the glacier - as the glacier melts the subglacial streams deposit the load on the floor to form eskers
- as its fluvioglacial deposit it is sorted by size
- stones are more rounded due to attrition
attrition
erosion
when the rocks hit off each other, chipping away and rounding them
national park
definition
area recognised for natural beauty, economic potential and is protected by strict regulation to preserve the environment.
honey-pot site
definition
area that is planned to attract tourism
footpath erosion
conflicts in LDNP
conflict
- the ground is trampled stopping grass growing; it gets muddy and the path is worn away
solutions
- signposts - people wont read them
- cloche netting - protects ground but looks unnatural
- stone pitching - looks unnatural
- fix the fells holiday - educates small number of people
scaffel pyke, lake district
traffic congestion
conflicts in LDNP
conflict
- park on side of narrow roads
- restricted parking in honeypot sites
- congestion
solutions
- bus timetables on attraction leaflets - encourages public transport, not always convinient
- park and ride - people like to have their own car
- large car parks on edge of honeypot site - reduces congestion
keswick, lake district
