Glacial Erosion+transportation

Question 1

What processes erode the valley floor?

Answer 1

Abrasion and plucking

Question 2

What is plucking?

Answer 2

When the ice is in contact with the rock surface freezes around the rock and as the glacier moves forwards it plucks the rocks away from the valley

Question 3

What is abrasion?

Answer 3

Debris carried along by the glacier that scrapes martial off the valley walls + floor

Question 4

What occurs in meltwater erosion?

Answer 4

Glaciers produce large amounts of meltwater that make the streams powerful enough to erode the valley floor through erosion processes

Question 5

What is weathering?

Answer 5

First shattering - breaks off the back and side walls of the valley
-meltwater freezes in cracks,expanding and breaking away at the rocks

Question 6

What are the three main ways debris is transported in a glacier?

Answer 6

Supraglacial - material carrier in top of the glacier surface

Englacial - carried within the body of the glacier

Subglacial- moved along at the base of the glacier

Question 7

What is the unsorted deposited material called?

Answer 7

Till ( or Boulder clay)

Question 8

Where is ablation till and lodgement till deposited?

Answer 8

Lodgement - spread on the valley floor beneath the glacier

Ablation till - dropped by the glacier as it melts

Question 9

what is freeze shattering/thaw?

Answer 9

when water fills the cracks and then freezes causing them to expand by 9%
this creates pressure on the rocks and eventually enlarging them
this process occurs over and over again and results in rock breaking up then appearing as scree

Question 10

what is frost heave?

Answer 10

when the active layer begins to refreeze (periglacial) and ice crystals develop
this increases the volume of soil and causes upward expansion of the soil surface