Examkin

Question

Difficulty: HardRelief and Major Landforms of Africa

The Ruwenzori Mountains located along the border of the Democratic Republic of the Congo and Uganda differ fundamentally in their structural origin from nearby prominent peaks such as Mount Kilimanjaro and Mount Kenya within the East African Rift System. Which of the following best explains this geological distinction?

  1. The Ruwenzori Mountains were formed by tectonic uplift of a basement block (horst) between parallel faults, whereas Mount Kilimanjaro and Mount Kenya were built up by volcanic eruptions along the rift zone.Answer
  2. B
    The Ruwenzori Mountains resulted from alpine folding of marine sedimentary strata during the Tertiary period, whereas Mount Kilimanjaro was produced by rift valley subsidence and graben formation.
  3. C
    The Ruwenzori Mountains are depositional landforms accumulated by upper-course river action, whereas Mount Kilimanjaro was shaped predominantly by wind erosion and mass wasting.
  4. D
    The Ruwenzori Mountains represent a series of eroded volcanic plugs, whereas Mount Kilimanjaro and Mount Kenya formed through compressional faulting and crustal warping.

Answer

The Ruwenzori Mountains were formed by tectonic uplift of a basement block (horst) between parallel faults, whereas Mount Kilimanjaro and Mount Kenya were built up by volcanic eruptions along the rift zone.
The correct answer accurately contrasts the tectonic origins of landforms in East Africa. The Ruwenzori Range is an exceptional block mountain (horst) formed by the upward displacement of crystalline basement rock between parallel faults within the East African Rift system. In contrast, nearby peaks like Mount Kilimanjaro and Mount Kenya were created through intense volcanic activity, where repeated lava flows and pyroclastic materials accumulated around eruptive vents along the rift fractures.

Step-by-Step Solution

1
Identify the geological landform classification of the Ruwenzori Mountains.
The Ruwenzori Range consists of pre-Cambrian metamorphic crystalline basement rocks uplifted between fault lines (a horst mountain).
Unlike most high East African mountains, Ruwenzori is non-volcanic.
2
Identify the structural origin of Mount Kilimanjaro and Mount Kenya.
Both are massive volcanic cones (stratovolcanoes) formed by lava extrusion associated with rifting along the East African Rift System.
Tectonic extension allowed mantle magma to erupt and accumulate high volcanic peaks.
3
Compare the origins to select the correct structural distinction.
Ruwenzori represents horst block uplift, while Kilimanjaro and Mount Kenya represent volcanic accumulation.
Distinguishing block mountains from volcanic landforms within the rift belt is essential for understanding African relief.

Key Concept

Horst (Block Mountain) vs Volcanic Landform Origins in the East African Rift System
Estimated Time:2m 0s
Rate this question

Topics

Relief and Major Landforms of Africa

More questions from this topic