Glacial Environments Flashcards
Define the process of abrasion
Where the glacier moves pebbles against the rock, acting like sandpaper which smoothes the rock out.
Define the process of plucking
Plucking is a process of erosion which occurs during glaciation where ice and glacier moves over the surrounding rock and pulls away chunks which leaves gauges and jagged from frozen debris plucked from the rock
What is basal sliding?
During the immersion basal sliding occurs when meltwater lubricates the glacier enabling it to slide downhill
What is internal deformation?
During the winter, internal deformation occurs when the glacier becomes frozen to the rocky surface, and the sheer weight of the ice deforms the rock and the glacier slowly moves downhill.
What is a glaciated environment?
A glaciated environment is one where glaciers transport sediment with ice and is deposited where the ice melts. Features that occur at glacial environments can be deposition, erosion, etc.
What is an example of a relict area in the UK?
Snowdon
Define a glacier.
A glacier is a slowly moving mass of ice formed by the accumulation and composition of snow from mountains which is compressed to for, the ice which moves slowly downhill, where features such as erosion and deposition occur.
What is the difference between erosion and weathering?
Erosion tends to involve the movement of weathered / eroded rock or soil, whereas weathering is the wearing down of rock which cannot move
What is freeze-thaw weathering?
Freeze thaw-weathering occurs when the water continually enters cracks in the rock where it freezes overnight and the ice expands which eventually breaks the rock apart and weathers it away.
What is moraine?
Moraine is sediment transported by a glacier, and is specifically a mass of rock fragments resulted from freeze-thaw weathering and erosion from the idea transported by a glacier
Define ground moraine.
The material dragged underneath the glacier and left behind when the ice melts
Define Lateral moraine.
Formed at the edges of a glacier, and mostly scree material which has fallen off the valley sides due to freeze thaw weathering when the ice melts, and this moraine forms a low ridge on the valley side
Define medial moraine -
When attributing glacier joins the main glacier two lateral moraine will merge to form a single line of sediment called medial moraine which runs down the centre of the main glacier. On melting, the medial moraine forms a ridge down the centre of a valley
Define terminal moraine.
Terminal moraine is huge amounts of material pile up at the snout of a glacier forming a high ridge across the valley
Which part of the glacier flows the fastest?
The centre of the glacier flows faster than the edges, and the top of a glacier flows faster than the bottom. This is due to FRICTION with the bedrock and valley sides.
What is the process of freezing and refreezing called?
Regelation
What is attrition?
Attrition is the sediment carried often in rivers or in the sea that are formed by rocks and pebbles constantly colliding with each other which wears them away as they gradually become smaller, rounded and smoother.
How are corries formed?
Corries are formed when snow accumulates in the hollow which is compressed into ice. Freeze thaw weathering and plucking steepen the back wall, while the rotational slip and abrasion gouges the hollow deeper. Scree and moraine from freeze-thaw weathering and plucking accumulate above the tarn once the ice has melted. This is now called a Corrie.
How is an arête formed?
An arête is formed when two back-to-back corries meet to create a very steep ridge in between
How is a pyramidal peak formed?
A pyramidal peak is formed when 3 corries meet and has 3 steep edges
What are striations?
Striations are formed by rock being carried underneath the glacier and as it is dragged underneath the glacier it leaves deep scratches in the rock
What is the difference between plucking and abrasion?
Abrasion causes smoother surfaces, whereas plucking causes more jagged surfaces
What is the name of the landform formed then abrasion and plucking occurs?
Roches Moutonées
Note
Abrasion and plucking can remove even the hardest of rock because they are so powerful
What is a truncated Spurs?
A steep edged valley which can be found in the Lake District, Snowdonia, etc.
What is a misfit stream?
The stream inside a U-Shaped valley
What are hanging valleys?
Hanging valleys are where streams meet a truncated Spur to form a waterfall (!)
What are ribbon lakes?
Ribbon lakes are formed when glaciated ice melts into shallow areas leaving water behind
What are glacial troughs?
Glacial troughs are steep sided, wide and flat bottomed valleys which are formed by abrasion. Individual glaciers which occupy the river valleys erode through abrasion forming the U-Shapes glacial troughs
What is a truncated spur?
A truncated spur is formed when a glacier cannot flow around existing interlocking Spurs, and so must cut straight through them forming steep edged truncated Spurs
What are hanging valleys?
Hanging valleys are smaller tributary valleys above the main glaciated trough. They are formed when the smaller glaciers could not erode down to the same level as the glacier. They are often measured by waterfalls.
What are ribbon lakes?
Long, narrow lakes often 10s of metres deep, most of which resulting from severe erosion of the glacial trough. This happens when the ice becomes thicker after a tributary glacier has joined or alternatively where a weaker bond of rock has eroded more easily.
What are erratics?
Erratics are large chunks of rock left behind after glacial melting with a unique geology to their surroundings
What is glacial till?
Glacial till is the collective term for sediment transported by a glacier
What are drumlins?
Drumlins can be formed from rapid movement or glacial ice which deposits the material. They are elongated mounds of glacial till which gets deposited UNDERNEATH THE ICE
What are kettle holes?
Kettle holes are depositional landforms formed when a glacier moves over a hole in the ground, and ice the glacier has moved completely over it, the idea remains in the hole, but melts, causing a small lake (kettle hole)
How can one determine direction of e flow in drumlins?
Steeper side indicates the direction from which the ice moved
What is a problem with determining direction of glacial movement from drumlins?
It can be difficult to determine direction of the ice flow because they can be altered by the glacier?
Why are erratics useful?
They an indicate history of a glacier through their paths of the past
What are some activities in the highland areas of the Lake District?
Hiking
Rock climbing
Zip lining
(Providing economic opportunity through tourism and local adventure seekers)
What are some activities in lowland areas of the Lake District?
Walking
Fishing
Horse riding
Boating
(Provides economic opportunity through tourism or local adventure seekers)
SEE BOOK FOR TABLE ON ADVANTAGES AND DISADVANTAGES OF -
FARMING
FORESTRY
QUARRYING
TOURISM
.
Advantages of wind farms in the Lake District
Provides power to residents
Means energy can be provided from a renewable source as opposed to diesel
Positive for the long term for the environment
Disadvantages of wind farms in the Lake District
Impacts views of landscape
Very environmentally damaging in the short term (destroys environment, ecosystems, etc)
Construction of turbines may decrease levels of tourism
Local landowners may be forced to sell their land
Why is the Lake District a popular attraction?
Famous mountains, eg. Hellvellyn Famous lakes, eg. Windermere Fascinating landforms (formed by glaciers for example) Inspiration for writers Scenery Scenic towns and villages Popular activities such as hiking Etc
Advantages of tourism in the Lake District
Provides job opportunities
Supports local economy
New businesses can be supported and made
Tourists are happy taking part in activities
Disadvantages of tourism in the Lake District
More people means more waste so more damage to environment
More tourists means more damage to landscape because of erosion and travelling by car or by feet
Prices increase in shops for locals due to tourism season
