Landforms Of Glacial Erosion Flashcards
Types of glacial erosion
Abrasion - the scouring away of base and sides by material in the ice. Produces strait ions and rock flour.
Plucking - friction between ice and rock causes melting. Water freezes back onto the rocks and pulls them away as the glacier moves.
Leaved behind a jagged landscape.
Corrie
Found at the top of pyramidal peaks.
It is an armchair shaped hollow with a steep back wall and over deepened basin.
Starts at a dip in the rock. The hollow is deepened by nivation. There is debris via freeze thaw that gets into the hollow via bergschrund crevasse; this material allows abrasion and rotational flow to deepen the basin, leaving a rock lip.
If it fills with water, it is known as a tarn.
Truncated spur
A glacier, being more powerful than a river, can power through the landscape.
It does not meander through interlocking sports, instead, cuts through them, leaving a steep cliff with a lack of vegetation.
Ribbon lake
A lake that has formed in a trough basin. They are anywhere in a glacial valley but the top.
E.g. Wast water, lakes
Fjord
During glaciation, the glacier cuts a deep U shaped glacial trough that it below sea level in its lower course.
Post glaciation, sea levels rise and flood the valley.
E.g. Milford sound, N.Z
Roche moutinée
A mass of more resistant rock attached to the valley floor.
Ice moved over the upstream sides, causing striations.
It plucks on the downstream side, causing a jagged edge.
Knock and lochan
Hills and hollows in lowland areas.
Erosion deepened the hollows which fill with water (lochan) and the mounds that surround it are the knock.
E.g. Scottish lowlands
Crag and tail
Similar to roche moutinée BUT ice flows the other way.
The glacier plucks the upstream side and moraines are deposited on the downstream side.
E.g. Edinburgh castle is built on a crag.
Hanging valley
The main glacier carves the valley much deeper than the tributary glacier (due to the volume of ice in the glacier)
Post glaciation, tributary is left high and a waterfall connects the valleys
E.g. Church beckon, Conniston
