Question 1 Report
At a field camp in the Sahara, Fig. 1 shows a geologist examining a mesa. The flat top is made of hard rock, but softer layers below have been worn back. A smaller flat-topped remnant stands nearby. The group is studying how differential erosion changes desert landscapes over time.
(a) Which landform is the smaller remnant most likely to be: butte, delta or ox-bow lake? [1]
(b) Outline why the hard cap rock is important in the formation of a mesa. [2]
(c) Draw a dashed line on Fig. 1 to show one possible future cliff position after erosion. [2]
(a) Butte [1] (b) Cap rock is more resistant to erosion [1]; it protects softer rock beneath until undercutting causes cliff retreat [1]. (c) Dashed line set back from a present mesa cliff face, roughly parallel to it [2]
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