O-LevelGeographyThe natural environment2217/12 · May/June 2012 · Q325 Marks

(a) Study Photograph F (Insert), which shows a river valley.

(a)(i)Describe the shape of the valley shown in Photograph F.[1]
(a)(ii)Describe two features of the river shown in Photograph F.[2]
(a)(iii)Suggest three ways in which the river shown in Photograph F could be carrying out erosion.[3]
(a)(iv)Name and describe two methods by which rivers transport their load. Method 1 Description Method 2 Description[4]
(b)Study Photograph G (Insert), which shows rocks where biological weathering is taking place.
(b)(i)Describe how biological weathering has occurred in the area shown.[3]
(b)(ii)Explain why biological and chemical weathering are rapid in areas which are hot and wet.[5]
(c)Describe and explain the process of freeze-thaw weathering. Include fully labelled diagrams.[7]

This question uses a diagram from the original paper, which isn't shown here. Open the full paper from the past papers archive to see it.

Mark scheme

Marking points from the official mark scheme (May/June 2012). The mark or mark type is shown in brackets.

[1] (a) (i) V-shaped/steep sided
[2] (a) (ii) Ideas such as: irregular long profile/waterfalls/rapids; debris in channel/rocky; shallow/low depth; narrow; turbulent/white water; winding/twisting; low volume/small etc.
[3] (a) (iii) hydraulic action/weight/power of water/loosening of unconsolidated/soft materials/pressuring of air in cracks; abrasion/corrasion/river uses load it is carrying to erode/sandpapering action etc. corrosion/solution/chemicals/acids in water/dissolve rocks; attrition/particles hitting each other are reduced in size
[4] (a) (iv) materials being pushed/rolled along (traction); materials being picked up by water and bounced along the bed/series of hops (Saltation); materials suspended/carried within the water (Suspension); materials dissolved in the water (Solution)
[3] (b) (i) Ideas such as: seeds fall into cracks in rocks; plants/roots grow in cracks; cracks widened/stress exerted; rocks broken apart; organic acids help decomposition of rocks etc.
[5] (b) (ii) Ideas such as: rate of chemical weathering doubles with every rise of 10°C; as there is presence of water for solution (dev); large amounts of rainfall which is acidic due to natural reaction between carbon dioxide and oxygen cause more chemical weathering; more biological weathering as there is far more plant/tree growth; therefore there will be more animals to cause biological weathering (dev) and more likelihood of tree roots in cracks/organic acids etc. (dev); more rapid release of CO2 from decay of plants etc.
[7] (c) Level 3 (7 marks) Comprehensive and accurate statements describing/explaining the process of freeze-thaw weathering including appropriate labelled diagrams (s).