O-LevelGeographyThe natural environment2217/12 · May/June 2015 · Q325 Marks

(a) Study Photographs A, B and C (Insert), which show the results of different types of weathering.

(a)(i)What is meant by weathering?[1]
(a)(ii)Match the three types of weathering listed with the Photographs A, B and C by completing the table below. Type of weathering Photograph Biological Exfoliation Freeze-thaw[2]
(a)(iii)Explain how rocks are weathered by exfoliation.[3]
(a)(iv)Explain how freeze-thaw weathering occurs.[4]
(b)(i)Study Fig. 5, which shows information about weathering. [Figure 5] Using Fig. 5 only, describe how rock type and soil cover influence the rate of weathering.[3]
(b)(ii)Describe and explain how climate influences the rate of weathering.[5]
(c)Describe and explain the distribution of fold mountains. You should refer to named examples.[7]

Mark scheme

Marking points from the official mark scheme (May/June 2015). The mark or mark type is shown in brackets.

[1] (a) (i) Breakdown of rock in situ (or alternative wording)/ decomposition or disintegration of rock
[2] (ii) C (Biological) A (Exfoliation) B (Freeze-thaw) All 3 correct = 2 marks 1 or 2 correct = 1 mark
[3] (iii) heating during day/high temperatures during the day; cooling during night/low temperatures at night (or alternative heating and cooling); rock/outer layer expands when heated; rock/outer layer contracts when cooling; (or alternative expansion and contraction); (outer layer of) rock peels/(outer layer of) rock falls off/peels like an onion.
[4] (iv) water enters cracks in rocks; temperatures fall below 0C/temperature falls below freezing; ice forms/water freezes; takes up more space than water/it expands; enlarges crack/widens the joints; pieces of rock break off/scree forms; temperatures rise and ice melts; repeated process etc.
[3] (b) (i) faster rate of weathering if rock is soluble/high rate of solution; faster rate if rock is jointed/if rock has many lines of weakness; faster rate if soil is thick etc. NB: Accept vice versa answers. Focus is on description not explanation. References to hard or soft rock and rainfall and temperature are irrelevant.
[5] (ii) more weathering when it is hot or vice versa; more weathering when rainfall is high or vice versa; more/especially chemical weathering/carbonation/oxidation (dev); as it speeds up the reactions; as plants grow more quickly; more/especially biological weathering (dev); more exfoliation/physical weathering where alternate hot and cold temperatures; more freeze-thaw/physical weathering when temperatures fluctuate around zero etc.
[7] (c) Level 1 (1–3 marks): Statements including limited detail describing and/or explaining the distribution of fold mountains. Level 2 (4–6 marks): Refers to at least one named example More developed statements describing and/or explaining the distribution of fold mountains. NB: MAX 5 if no named or inappropriate example. Accept names of mountains or mountain ranges. One example is fine. Level 3 (7 marks): Uses at least one named example. More developed statements describing and explaining the distribution of fold mountains. Including some place specific reference. (If there are three developed descriptive statements, explanation can be at L1 to award this level and vice versa). Content Guide: Answers are likely to refer to; plate movement, continental plates meet/collision margins, subduction/continental and oceanic plates meet/destructive margins, plate density, uneven distribution, narrow belts, uplift etc. Place specific reference could consist of: named plates mountains mountain ranges