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SSC Selection Post 2024 PYQ — Question 50

SSC Selection Post - Higher Secondary Level - 25 June 2024 - Shift 2 • General Awareness • Q50

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The highly viscous, mechanically-weak and ductile region of Earth's upper mantle is called:

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Correct answer: B

Explanation

The correct answer is Option 2 i.e. asthenosphere.

  • The highly viscous, mechanically-weak and ductile region of Earth's upper mantle is called asthenosphere.
  • The asthenosphere is a denser and weaker layer located beneath the lithospheric mantle, extending from about 100 kilometers (62 miles) to 410 kilometers (255 miles) below the Earth's surface. Due to the high temperature and pressure in this zone, rocks become semi-molten, softening and partially melting.
  • The asthenosphere is generally more viscous than the lithosphere. The boundary between these two layers, known as the lithosphere-asthenosphere boundary (LAB), marks a significant change in ductility, which is the ability of material to deform under stress.
  • This boundary is crucial for geologists and rheologists, who study the flow and deformation of Earth’s materials.