glacial erosions

Question 1

plucking/quarrying

Answer 1

Plucking happens when a glacier moves over bedrock that has cracks. The ice melts a bit and refreezes around the protuding rocks.

As the glacier moves forward, it pulls these rocks away, leaving a rough, jagged surface behind.

roche moutonee

Question 2

abration

Answer 2

• occurs when debris carried by a glacer scrapes the valley walls and floor.
• the scraping of one rock against another can leave behind striations on the rock face
• striations record the direction in which the glacier moved

Question 3

crushing

Answer 3

crushing is where the weight of ice exerts pressure on the bedrock below
- it chips the rock into large fragments
- fractures in the rock can deepen and expand, this is called dialation

Question 4

basal melting

(meltwater erosion)

Answer 4

meltwater can cause abrasion, erosion by hydrolic action, attrition and corrosion

When meltwater is under high pressure, it can carve out channels and hollows beneath the glacier

Question 5

freeze-thaw weathering

Answer 5

creates cracks in rocks by water moving into a crack, freezing and expanding by 9%, then thaws when the temperature rises

this continuous cylce weekens the rock causing it to shatter