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.
