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Difficulty: MediumPhysical Geography of the World

With reference to tectonic plate boundaries and associated geomorphic features, consider the following statements:
1. Deep ocean trenches are characteristic relief features of continental-continental convergent plate boundaries.
2. The formation of the Himalayan mountain range is a classic result of convergence between the Indian Plate and the Eurasian Plate.
3. Volcanic activity is minimal or absent along continental-continental collision zones compared to oceanic-continental subduction zones.

Which of the statements given above is/are correct?

  1. A
    1 and 2 only
  2. 2 and 3 onlyAnswer
  3. C
    1 and 3 only
  4. D
    1, 2 and 3

Answer

Statements 2 and 3 are correct.
The uplift of the Himalayas is driven by the continental collision of the Indian and Eurasian plates. Furthermore, because both colliding continental blocks are light and buoyant, subduction-driven volcanism is virtually absent compared to subduction zones involving dense oceanic crust. Deep ocean trenches only form where oceanic crust subducts, making the option containing statements 2 and 3 only correct.

Step-by-Step Solution

1
Analyze Statement 1 regarding landforms at continental-continental convergent boundaries.
Deep ocean trenches (e.g., Mariana Trench) form where oceanic lithosphere subducts into the mantle. When two continental plates collide, neither plate subducts deeply due to low density, resulting in mountain crustal thickening rather than deep trench formation. Hence, Statement 1 is incorrect.
Identify the tectonic setting responsible for oceanic trenches vs. folded mountains.
2
Evaluate Statement 2 regarding the tectonic origin of the Himalayas.
The collision between the Indo-Australian (Indian) Plate and the Eurasian Plate is the textbook example of a continental-continental convergent boundary that uplifted the Himalayas. Hence, Statement 2 is correct.
Verify regional geomorphological examples of plate collision.
3
Evaluate Statement 3 regarding volcanism at continental collision boundaries.
Unlike oceanic-continental convergence where hydrated oceanic slab subduction fuels volcanic arcs (e.g., the Andes), continental-continental collision lacks continuous subduction of basaltic/oceanic crust, leading to minimal or absent volcanic activity. Hence, Statement 3 is correct.
Understand magma generation mechanisms across different convergent boundary types.

Key Concept

Plate Tectonic Landforms and Convergent Boundary Dynamics
Estimated Time:1m 15s
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Topics

Physical Geography of the World

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