N5 geography

Question 1

What is plucking

Answer 1

Ice attaches to a rock face and, under the influence of gravity, pulls away large pieces from it. This results in steeper landscapes

Question 2

What is abrasion

Answer 2

Rocks trapped between moving ice and the stationary rock below act like sandpaper, carving a deep and smooth pathway in their wake. Leads to deeper and smoother terrains.

Question 3

What is frost shattering (freeze thaw weathering)

Answer 3

Water infiltrates the tiny pores in rocks. As it freezes, it expands, causing the rock to eventually crack or shatter. This action can lead to cracks in rocks widening by as much as 9%.
Produces jagged rock surfaces.

Question 4

Explain the formation of a corrie(3 steps)

Answer 4

1. Before glaciation: Snow accumulates in a north-facing hollow as it doesn’t receive direct sunlight.As more snow accumulates, the air between snowflakes gets compressed, leading to the formation of ice.
2. During glaciation: Plucking forms a steep back wall. Abrasion results in a deep and smooth base. Frost shattering affects the peak, rendering it jagged. Rotational slip aids the corrie’s movement out of the hollow. As the glacier moves uphill out of the hollow, it loses energy. This leads to the deposition of rocks, forming the corrie lip.
3. After glaciation: As temperatures increase, the glacier starts to melt. Remaining ice in the glacier converts to meltwater, which is retained by the corrie lip, creating a tarn or corrie lochan.

Question 5

Explain the formation of an arête

Answer 5

Aretes form when two corries develop back-to-back. As these corries expand due to erosion, they carve deeper into the mountain, leading to a narrow ridge between them. One of the main erosive forces shaping aretes is frost shattering. This occurs when water infiltrates cracks in the rock, freezes, and expands. As this cycle repeats over time, larger pieces of rock are dislodged from the back wall of each corrie. The continuous frost shattering makes the ridge between the two corries increasingly jagged and pronounced, accentuating the knife-edge appearance. With the ongoing erosion and frost action, the ridge eventually takes on the distinctive, narrow profile of an arete, becoming a striking feature in the landscape.