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Question

Difficulty: MediumRelief and Major Landforms of Africa

Match each major African relief feature listed in Column A with its corresponding structural and geological origin in Column B.

  • Ahaggar MassifAn elevated highland complex in the central Sahara formed by broad mantle-plume uplift of ancient Precambrian crystalline basement rocks.
  • Congo BasinA vast interior cratonic downwarp creating a saucer-shaped drainage basin surrounded by elevated plateaus.
  • East African Rift ValleyA major linear trough formed by crustal extension, bounded by steep parallel normal fault scarps.
  • Cape Fold BeltAn ancient belt of fold mountains formed by crustal compression during the Palaeozoic era.

Answer

Ahaggar Massif pairs with the elevated Precambrian crystalline highland in the Sahara; Congo Basin pairs with the vast interior cratonic downwarp; East African Rift Valley pairs with the extension-formed linear trough bounded by normal fault scarps; Cape Fold Belt pairs with the ancient Palaeozoic fold mountain belt.
Each feature correctly matches its structural type: the Ahaggar Massif is an uplifted crystalline basement block in the Sahara; the Congo Basin is a classic continental downwarp (basin structure); the East African Rift Valley is an extensional fault trough; and the Cape Fold Belt is an ancient Palaeozoic fold mountain range.

Step-by-Step Solution

1
Analyze the geological classification of Saharan high massifs such as the Ahaggar.
Identify that the Ahaggar Massif consists of exposed Precambrian basement rocks uplifted into a high plateau complex.
Swell uplift in northern and central Saharan shield regions formed high interior basement massifs.
2
Examine the formation mechanism of the interior African drainage depressions like the Congo Basin.
Identify the Congo Basin as an epeirogenic downwarp (basin-and-swell structure).
Continental basin-and-swell tectonics in Africa created broad central depressions surrounded by rimming highlands.
3
Identify the structural process producing the East African Rift System.
Match it to extensional faulting and graben formation bounded by normal fault scarps.
Tensional forces pull the crust apart, causing central blocks to sink relative to adjacent horsts.
4
Classify the fold mountain structures of Southern Africa.
Match the Cape Fold Belt to Palaeozoic crustal compression and folding.
Unlike the Cenozoic young fold mountains of the Atlas, the Cape ranges represent older Palaeozoic orogenic activity.

Key Concept

Structural classification and tectonic origin of major landforms of Africa
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Topics

Relief and Major Landforms of Africa

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