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Zorluk: OrtaDrainage Systems: Major Rivers and Lakes of Africa

Lake Victoria is the largest lake in Africa by surface area, yet it differs fundamentally in origin from neighbouring Great Lakes such as Lake Tanganyika and Lake Malawi. Which of the following geological processes best explains the formation of Lake Victoria?

  1. Broad crustal downwarping of the plateau region lying between the eastern and western rift branchesCevap
  2. B
    Extensive faulting and deep subsidence along a linear rift valley graben floor
  3. C
    Damming of a major river drainage network by volcanic lava flows and glacial moraines
  4. D
    Marine transgression followed by water entrapment during continental uplift

Cevap

Broad crustal downwarping of the plateau region lying between the eastern and western rift branches
The correct answer identifies broad crustal downwarping as the origin of Lake Victoria. Tectonic stresses associated with the uplift of the surrounding rift shoulders caused the central East African plateau to sag gently downward, creating a vast, shallow saucer-shaped basin.

Adım Adım Çözüm

1
Differentiate between the structural types of African lakes
Lakes in East Africa are broadly classified into deep tectonic rift lakes (located inside fault grabens) and shallow basin lakes (located in crustal depressions).
Geological origin determines Lake Victoria's distinct saucer shape and shallow depth relative to its enormous surface area.
2
Analyze the formation mechanism of Lake Victoria
Tectonic forces caused the plateau between the Eastern (Gregory) Rift and Western Rift to warp downward, forming a huge, shallow basin that intercepted regional river flow.
This downwarping reversed and diverted pre-existing river systems into the central depression, filling it to form Lake Victoria.

Anahtar Kavram

Crustal Downwarping vs. Rift Valley Lake Formation
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Konular

Drainage Systems: Major Rivers and Lakes of Africa

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