Slopes

Question 1

Name the main topographic features of South Africa

Answer 1

Great - & Little Karoo(Karoo Basin), Plateau(1000m+ altitude), Great Escarpment(borders plateau), Kalahari Depression, Cape Fold Mountain(2 belts surround little karoo)

Question 2

Identify the highest and lowest points of the Plateau and Great Escarpment

Answer 2

Lowest - Kalahari depression

Highest - Drakensberg

Question 3

Name the 4 types of slopes. What is the difference

Answer 3

1. Primary slopes- These form due to crustal forces (Folding, faulting)
2. Primary erosion slopes- Slope has formed due to erosion of the land.
3. Secondary erosion slopes - Form from weathering/erosion of primary- and primary erosion slopes
4. Deposition slopes - Form from deposited weathered material

Question 4

Define endogenic

Answer 4

Forces that occur underground/internally. I.e folding or faulting

Question 5

define exogenic

Answer 5

Forces that occur above surface/externally. I.e erosion or deposition

Question 6

How are slopes classified

Answer 6

1) Gradient:
1. 1. Gentle slope- angle is low; contours are widely spaced
1. 2. Steep slope- angle is high; contours are close together
2) Shape:
2. 1. Concave- Upper angle is high and lower angle is low; Contours are close at the top and wide at the bottom
2. 2. Convex- Upper angle is low and lower angle is high; Contours are wide at the top and close at the bottom

Question 7

How can people use slopes

Answer 7

1. Settlement - People build on slopes when there is no space or for view. The north-facing slope that is popular in SA
2. Agriculture - Steep slopes for forestry; Gentle slopes for vineyards. To prevent soil erosion for farming, contour ploughing is needed.
3. Recreational - Hiking, skiing, mountaineering etc
4. Communication - Transport routes on mountains follow the contour of the land.

Question 8

Name the 5 elements of a slope

Answer 8

Crest, Free face, Talus, Knickpoint, Pediment,

Question 9

Briefly explain the 5 elements of a slope

Answer 9

1. Crest - Convex slope at the top of a slope
2. Free face/cliff - exposed rock, weathering widens joints
3. Talus - Formed from eroded material from the cliff. Rat of accumulation is similar to the rate of erosion
4. Knickpoint - Sharp change in gradient at base of Talus
5. Pediment - Low-angle concave

Question 10

Explain the difference between humid and arid areas with regard to slopes

Answer 10

Humid - The slopes are covered in soil and vegetation because the more material collects on the slope than is removed
Arid - the rate of transportation of weathered material is > the rate of new weathered material

Question 11

explain the theory of Slope Decline

Answer 11

Humid climate

1. Steep slopes develop by rivers eroding vertically
2. Become less steep due to water washing down the slope. Continues till the land is almost a flat plain AKA peneplain
3. Upper part is convex and the lower part is concave

Question 12

Explain the theory of Slope Replacement

Answer 12

1. landform starts as a straight rock slope with uniform resistance/ equal weathering.
2. As talus accumalates, the steep slope is replaced with a gentler slope
3. Slope doesn’t lower and mid part is concave

Question 13

Explain the concept of Slope Retreat

Answer 13

Semi-arid climate

1. Steep slopes are created when rivers erode vertically into uplifted land.
2. Erosion continues till the removal of the weathered material is = to the supply of new material
3. The crest, scarp, and talus erode back parallel to themselves.
4. Pediment grows and eventually becomes a flat plain AKA pediplain.
5. AKA Parallel retreat ( eroding backwards, but no loss of height)