erosional landforms

Question 1

where do erosional and depositional landforms occur?

Answer 1

upper course: erosional landforms
middle course: erosional and depositional landforms
lower course: depositional landforms

Question 2

define a ‘v-shaped valley’:

Answer 2

a narrow, steep-sided valley, formed as a result of vertical erosion by a stream or a river.

Question 3

how are v-shaped valleys created?

Answer 3

• a river transports material along its bed, known as its load
• the material cuts downwards because of erosive processes such as abrasion and hydraulic action (vertical erosion), creating steep-sided banks
• the banks are left unsupported and they collapse, forming a v-shape (v-shape valley)

Question 4

define ‘interlocking spurs’:

Answer 4

ridges of high ground that project into v-shaped valleys. they occur on alternate sides of the valley and interlink like the teeth of a zip.

Question 5

explain the formation of interlocking spurs:

Answer 5

in the upper course, the river doesn’t have a huge amount of energy to erode, so when the river meets areas of hard rock that are difficult to erode, it has to wind around them. a series of hills form on either side of the river called spurs. as the river flows around these hills, they become interlocked.

Question 6

what is a river drainage basin?

Answer 6

the catchment area of land drained by the river. it’s surrounded by a watershed, which is the area of surrounding highland that separates different drainage basins.

Question 7

what is a waterfall?

Answer 7

a sudden fall of water over a steep drop.

Question 8

what is a gorge?

Answer 8

a deep, narrow valley with steep rocky sides creates as a waterfall retreats.

Question 9

describe the formation of a waterfall:

Answer 9

1. waterfalls form in the upper course. a band of hard rock overlays a band of soft rock. falling water and rock particles erode the soft rock below the waterfall, creating a plunging pool.
2. water and debris swirl around, eroding the rock through corrosion, further deepening the plunge pool and creating an overhang of hard rock.
3. hard rock overhang above the plunge pool collapses as its weight is no longer supported
4. erosion continues and the waterfall retreats upstream, leaving behind a gorge.