Lithosphere- Glaciation

Question 1

Glacial ice

Answer 1

Snow falls and accumulates
Snow slightly melts, meltwater sinks and freezes deeper
Snow compacts expelling air
Névé
Buried beneath new snow and called firn
Continues to be compacted from additional weight

Question 2

Plucking

Answer 2

Glacial ice melts (friction) and as it goes over an obstacle like a rock mass. The water refreezes because of the overlaying pressure of ice. It freezes in cracks and crevices, as the glacier moves, loose pieces of rock are pulled/ torn out.

Question 3

Abrasion

Answer 3

The rock debris embedded in the glacier, scrapes, scours and grinds against the valley floor. This wears away the underlying rock. Also provides additional rock material to assist in the process. The debris itself is also worn down to a fine powder which helps add abrasive capabilities.

Question 4

Freeze thaw weathering

Answer 4

Water seeps into cracks and pores in the rock, it freezes overnight when temperatures drop below 0°, expanding the volume and so exerting pressure on the crack.
When temperatures rise again, the ice melts and more water seeps into the widened crack.
This process repeats and eventually chunks of rock break away.

Question 5

Lateral moraine

Answer 5

Forms along the sides of the glacier
From plucked material and material fallen from the valley sides
After retreat these form mounds running along the base of the valley walls

Question 6

Medial moraine

Answer 6

At the point where two glaciers merge
Where two lateral moraines join together
Causes dark lines running through the centre of a glacier

Question 7

Ground moraine

Answer 7

Collects at the base of the glacier

May be deposited when the glacier retreats or may be transported further down the valley by meltwater

Question 8

Terminal moraine

Answer 8

Marks endpoint of the glacier at its furthest extent

Material is pushed to the snout of the glacier and forms a mound running from one side of the valley to the other