1.5 Glacial Landscapes and Processes (Paper 1) Flashcards
Describe the extent of the ice covering the UK during the last Ice age
Ice covered:
- all of Scotland
- the North of England
- most of Wales
- all of Northern Ireland
How long ago was the last ice age?
About 20,000 years ago
What is a glacier?
A mass of ice that covers the land
Why are glaciers important in explaining the UK’s physical landscapes?
As glaciers move, they erode the landscape, creating many of the UK’s physical landscapes
What causes a glacier to move?
The weight of the ice and gravity pulling it down hill
What is the main weathering process in a cold environment?
Freeze-thaw weathering
What is freeze-thaw weathering?
When water gets into the cracks in a rock, it freezes, expanding to form ice. This puts pressure on the rock. As the ice thaws, it reduces in size, releasing the pressure. This repeating process causes the rock to break apart
When glaciers move downhill, which two erosional processes happen?
- Plucking
- Abrasion
What is meant by ‘plucking’?
When meltwater on the bototm or sides of a glacier refreeze to surrounding rock. As the glacier moves, loose fragments of rock are pulled (‘plucked’) from the surface, leaving behind a jagged surface
What is ‘abrasion’?
Debris picked up by the glacier then scours (scrapes and scratches) the valley floor as the glacier moves over the landscape. It acts like ‘sandpaper’
What is ‘rotational slip’?
The curved movement of a glacier across a hollow in the landscape
What is ‘bulldozing’?
As a glacier moves, it pushes debris forward
What is ‘moraine’?
The accumulation of till that is deposited by the glacier
What is ‘till’?
Broken rock fragments left behind by a glacier. It is comprised of angular material of different sizes (unsorted)
When does deposition occur?
When ice melts
What is ‘outwash’?
The finer pieces of sediment that have been broken down and rounded by attrition, that have been washed away by meltwater and deposited
Name the 7 landforms created by glacial erosion
- Arête
- Pyramidal peak
- Corries
- Truncated spurs
- Hanging valleys
- Glacial troughs
- Ribbon lakes
What is an arête?
A narrow, steep sided ridge formed between two corries
What is a pyramidal peak?
A pointed peak of a mountain caused when three corries have formed on a mountainside
What is a corrie?
Large hollowed out depressions located on the hillsides
What are the characteristics of a corrie?
- Steep back wall
- Raised ‘lip’ at the front
- Sometimes contain a tarn (lake)
What process causes a corrie?
Erosion. As the ice moves by rotational slip, it erodes the hollow shape into the hillside
What is a ‘tarn’?
A lake left behind when glacial ice melts in a corrie
What is a ‘ribbon lake’?
When a glacier moves, it erodes the landscape, leaving hollows in the ground. Meltwater sits in these long, thin hollows leaving behind a ‘ribbon lake’
What is a ‘truncated spur’?
Ice is unable to flow around interlocking spurs that may have formed within the valley. As a result, the glacier cuts straight through leaving behind cliff like edges on the valley sides