The interior physiography of Africa is dominated by a characteristic basin-and-swell structure, forming vast inland depressions such as the Congo, Chad, and Kalahari Basins separated by intervening high plateaus. Which of the following geological processes responsible for this broad landscape architecture contrasts it structurally from the East African Rift System?
- Widespread epeirogenic warping of the stable Precambrian crystalline shield, resulting in broad crustal sagging and gentle uplift rather than localized rift faulting.Cevap
- BIntense alpine orogenic folding along convergent plate boundaries that buckled the continental crust into alternating synclinal valleys and anticlinal ridges.
- CVertical displacement along massive horst fault blocks produced by severe horizontal compression across the continental interior.
- DExtensive lower-course river erosion and chemical weathering that dissolved upper sedimentary layers to form deep structural hollows.
Cevap
Widespread epeirogenic warping of the stable Precambrian crystalline shield, resulting in broad crustal sagging and gentle uplift rather than localized rift faulting.
The interior relief of Africa is famously described as a 'basin and swell' topography. Because the continent is anchored by an ancient, stable crystalline shield, continental forces express primarily through epeirogenesis—slow, large-scale vertical crustal warping. Downwarping forms immense inland basins (such as the Congo, Chad, and Kalahari Basins), while upwarping creates intervening swells and plateaus. This structural flexing contrasts directly with localized tensional rifting seen in the East African Rift System.
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Basin and Swell Structure of Africa via Epeirogenic Warping