Paper 3 · June 2023 · Fluvial Geomorphology
The Masembura 1:50 000 extract shows steep sided hill masses rising to trigonometrical stations at 1315.8 m and 1317.2 m, standing well above a gently undulating plateau surface cut across the same granite. What is the most likely explanation for these hills?
AThey are terminal moraines, ridges of unsorted debris left along the front of an ice sheet that formerly covered the plateau surface and stood still long enough for the material it carried to be dumped in place.
BThey are volcanic cones built up by successive eruptions above a hot spot beneath the plateau.
CThey are resistant granite masses that survived while more heavily jointed rock around them was weathered and stripped away.
DThey are fold mountains raised by compression where two continental plates collided along this part of the craton.
Explanation
On the Zimbabwe craton the granite is not uniformly jointed. Where jointing is close, weathering penetrates and the rock is stripped to form the plateau surface; where the granite is massive and sparsely jointed it survives as an inselberg or dwala with bare exfoliating domes, which is what the contour packing on the extract shows.
Derived from ZIMSEC Advanced Level Geography 6037/3 Paper 3 Practical Test, June 2023 session, Q2