Glaciation Revision Flashcards
What is the process of snow accumulation in a corrie?
Snow accumulates in a north facing hollow, which is shaded from the sun, allowing snow to accumulate.
How is glacial ice formed in a corrie?
Accumulated snow compresses to form glacial ice.
What causes ice to move downhill in a glacier?
Ice moves downhill due to gravity.
What is plucking in glacial erosion?
Plucking steepens the backwall, where ice freezes onto rocks and pulls them out as the glacier moves.
What is abrasion in glacial erosion?
Abrasion occurs when rocks embedded in the ice scrape away at the base.
What is freeze-thaw weathering?
Freeze-thaw weathering is when water enters cracks in rocks, freezes, expands the cracks, and causes rocks to break apart.
What is a bergschrund crevasse?
A bergschrund crevasse may open up at the back of the corrie, allowing meltwater and rocks to reach the base of the glacier.
What is an example of a corrie?
An example is Brown Cove.
How is an arete formed?
An arete is formed when two corries erode towards each other, creating a sharp-ridged edge.
What is an example of an arete?
An example is Striding Edge.
How is a pyramidal peak formed?
A pyramidal peak is formed when three or more corries erode towards each other, turning a rounded peak into a pointed one.
What is an example of a pyramidal peak?
An example is the Matterhorn.
How is a U-shaped valley formed?
Former interlocking spurs may be cut off by the glacier, creating truncated spurs.
What is a misfit stream?
A misfit stream runs along the floor of a U-shaped valley as it no longer fits the width of the valley floor.
What is an example of a U-shaped valley?
An example is Glen Coe.
How is a ribbon lake formed?
A ribbon lake is formed when softer rock is eroded deeper than surrounding hard rock.
What can create a dam for a ribbon lake?
Terminal moraine can create a dam.
What is an example of a ribbon lake?
An example is Loch Muick.
How is a hanging valley formed?
A hanging valley is formed when tributary valleys are filled with smaller glaciers that have less erosive power.
What characterizes hanging valleys?
These valleys are suspended above the main valley and are usually categorized by waterfalls.
What is terminal moraine?
Terminal moraine is a ridge across a valley made up of till/boulder clay.
How does terminal moraine form?
As the glacier moves, it pushes sediment in front of its snout, and when the glacier melts, it deposits material.
What does terminal moraine mark?
Terminal moraine marks the furthest point the glacier has traveled.
What is a drumlin?
Drumlins are elongated mounds made up of unsorted material, including till and boulder clay.
How do drumlins form?
Drumlins form when a glacier becomes overloaded with sediment and deposits it while still moving.
What are the characteristics of a drumlin?
The steep ‘stoss’ side faces up-valley, while the gently-sloping ‘lee’ side faces down-valley.
What is an esker?
Eskers are meandering ridges formed by meltwater streams either within or underneath the glacier.
What materials make up an esker?
Eskers are made up of meltwater sands and gravels, sorted by size.
How are stones in an esker deposited?
Larger stones are deposited first by flowing water, and they tend to be more rounded due to erosion.
