Abrasion, crushing, plucking (quarrying) and basal melting.
1 of 9
Explain what is meant by 'abrasion'.
Rock fragments frozen into the base of moving ice grind down bedrock, eroding it and generating fine eroded material rock flour.
2 of 9
Explain what is meant by 'crushing'.
The pressure exerted by rock fragments embedded at the base of ice can chip fragments off the bedrock below.
3 of 9
Explain what is meant by 'plucking'.
Plucking removes chunks of bedrock (in fractured and jointed rock) by freezing water around them so they are pulled away by the ice mass as it moves over the top.
4 of 9
Explain what is meant by 'basal melting'.
The process is similiar to abrasion in rivers, but differs because water flowing at the base of ice can be under pressure, making abrasion a more powerful force.
5 of 9
Give some evidence for abrasion.
Glacially eroded rock surfaces often have striations: long, parallel scratches 1-10mm wide, tracing the path of eroding rock fragments.
6 of 9
Give some evidence for crushing.
Micro-features called chattermarks (wedge or crescent shaped depressions) are evidence of fracturing by crushing forces.
7 of 9
Give some evidence for plucking.
Plucking removes chunks of bedrock (in fractured and jointed rock) by freezing water around them so they are pulled away by the ice mass as it moves over the top.
8 of 9
Give some evidence for basal melting.
This process is similiar to abrasion in rivers, but differs because water flowing at the base of ice can be under pressure, making abrasion a more powerful force.
9 of 9
Other cards in this set
Card 2
Front
Explain what is meant by 'abrasion'.
Back
Rock fragments frozen into the base of moving ice grind down bedrock, eroding it and generating fine eroded material rock flour.
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