Physical Lanscapes in the UK - Glaciers Flashcards
How many years ago was the last ice age
22,000
What is a glacier
A large amount of ice/snow that originates on land and moves downwards
Glacier formation
- Glaciers form when snow remains in the same area year-round and slowly transforms to ice
- New layers of snow bury and compress the previous layers
- This compression forces the snow to re-crystalline, forming small sugar like grains
- Grains get larger and air pockets get smaller, snow slowly compacts and increases in density
- The snow turns to firn/neve - a state between snow and glacier ice
- This process takes more than 100 years
Freeze thaw weathering
Rainwater enters the cracks
Temperature drops and water freezes to ice
Ice expands forcing the rock apart - Expansion by 9-11%
Once the rock breaks in two and then it breaks into smaller pieces
The process repeats
Abrasion
Rocks at the bottom of the glacier grind over the bedrock - creates sharp grooves called striations
Plucking
A glacier moves over an area of rock, friction causes glacier to melt and water seeps into cracks - freeze thaw weathering occurs
Rotational Slip
The mass of the ice and slope act to make the ice move down slope in a curved or rotational movement
Till
Debris that is transported by glaciers in various ways
Bulldozing
When a glacier moves forwards it can act like an earth mover
Bulldozing rocks and debris to create a high ridge = moraine
3 ways till is carried in a glacier
Supraglacial - top
Englacial - middle
Subglacial - bottom
2 types material that forms when glacial till is deposited
Moraine Till - Angular Rocks and boulders
Outwash - Rounded rocks due to attrition by river erosion
4 types of moraine
Lateral
Medial
Ground
Terminal
Glacial Deposition - What and Why
When ice loses enrgy it starts to drop materials
Unsorted mixture of material is deposited anywhere
Lateral Moraine
Runs along the edges of the glacial trough
Medial Moraine
When two lateral moraines merge a large ridge of rock forms - thick dark strip running down the glacier
Ground Moraine
Gets lodged and deposited under the glacier
Terminal Moraine
Ridge that is made up of bulldozed material, by the snout of the glacier and allows glacier to advance
Landforms resulting from transportation and deposition
Drumlins
Erratics
The 4 types of Moraine
What are drumlins
Egg-shaped hills made up of mounds of till
What do drumlins show
The tapered end points in the direction of ice flow
How are drumlins formed
Ice from glaciers bulldozes a u-shaped valley
What are a group of drumlins called
A swarm
What are erratics
Large boulders that sit on top of a different type of rock on the landscape
Where are erratics transported
Far from the origin
Travel huge distances
Formation of a corrie and tarn
Snow accumulates in north face slopes
Snow can no longer hold weld - compressed into ice
Ice freezes at the bottom of the hollow - plucking occurs making the back wall steeper
Freeze-thaw weathering occurs at the top of the slope producing scree which is incorporated into glacier
Ice slides downhill, due to abrasion wearing away at the base of the corrie - corrie deepens
Less erosion at front of glacier - corrie lip forms
Ice in Corrie melts and tarn forms in centre
What is an Arête
Ridge formed by two back to back corries
What is a Corrie
A bowl shaped hollow with steep back walls and ridges
What is a Tarn
A small round lake in a Corrie
What is a Pyramidal Peak
When three or more corries form a single peak were the arêtes meet
What is glacial trough
The process of:
A glacier passing through a v-shaped valley and taking out the sides forming a v-shaped valley - by abrasion and plucking
What is a Hanging valley
Tributaries that water escapes from forms waterfalls
Which are referred to as hanging valleys
What are truncated spurs
The sides along the glacial trough
How are truncated spurs formed
Powerful ice removes obstacles, leaving a clear path
Forming a u-shaped valley
What are ribbon lakes
Long thin lakes that collect meltwater and rainwater
How are ribbon lakes formed
Different rates of erosion occur at different rock types - hard and soft
Some parts of the valley floor are over-deepened (soft)
Soft and hard rock examples
Soft = clay
Hard = graphite
AN example of an upland area in the Uk affected by glaciation
The Lake District
Two physical characteristics of the Lake District
Mountains and ridges
Wide steep sided U-shaped valley
State two human characteristics of the Lake District
Agriculture and Farming
Infrastructure - homes, energy, transport
Economic Activity in the Lake District
Tourism - Home to thousands of visitors a year
Quarrying - Lake District has tough rock, can be used for kitchens and pavement
Forestry - Fast growing trees in the Lake District are well suited for the weather
Farming - high quality livestock and healthy environment
Why is there conflict in the Lake District
Different Land Use
Conflict between tourists and locals
Tourists increase house prices - unaffordable for locals
Conflict between tourists and environment agency
Bikers erode footpath - ruin natural area
Conflict between quarrying and conservation
Quarrying destroys natural landscape making it unattractive
Conflict between locals and conservation
Wind turbines cause visual pollution
Reservoirs destroy habitats and disrupt water flow - economic benefits & reduce flooding
Honey Pot Site
A place of natural or human interest that attracts people in large numbers
This puts pressure on the environment and local population
Tourist attractions in the Lake District
Lake Windermere (Honeypot Site)
- Water sports
- Boating and fishing
Helvellyn (mountain Landscapes)
- Hiking
Ambleside (small town)
- Historic houses and gardens
- Beatrix potter’s house
Social Impacts of tourists
Almost 50 million people visit each year - pressure on facilities
Traffic congestion on narrow roads
High demand for properties - locals can’t afford
Jobs are seasonal
Environmental impacts of tourism
Foot path erosion
Pollution - traffic and litter
Economic impacts of tourism
Employment is boosted from tourism
Businesses are promoted by tourism
Jobs are seasonal
Management strategy for traffic congestion
Public transport is encouraged - bus routes for hikers
‘Give the driver a break’ - encouraged to not use cars
Management strategy for footpath erosion
Volunteers work with local groups to restore footpaths - local stone and sheep wool = more resilient
Encouraging people to stay on footpaths - more signs
Planting plants that withstand trampling - reduces erosion
