Question

Difficulty: MediumInternal and External Structure of the Earth

Match each structural layer or boundary of the Earth listed in Column A with its defining physical characteristic or compositional property in Column B.

  • Mohorovičić DiscontinuityBoundary separating the solid silicate crust from the underlying mantle
  • Gutenberg DiscontinuityBoundary marking the transition between the solid mantle and liquid outer core
  • LithosphereRigid outermost shell comprising the entire crust and uppermost solid mantle
  • AsthenosphereDuctile, semi-fluid upper mantle layer responsible for convection currents

Answer

Mohorovičić Discontinuity matches the boundary separating the crust from the mantle; Gutenberg Discontinuity matches the boundary between the mantle and outer core; Lithosphere matches the rigid outermost shell of crust and upper mantle; Asthenosphere matches the ductile semi-fluid upper mantle zone.
Each structural zone corresponds accurately to its physical state and boundary depth: the Mohorovičić discontinuity separates the crust from the mantle, the Gutenberg discontinuity separates the mantle from the outer core, the lithosphere represents the rigid outermost shell, and the asthenosphere represents the ductile upper mantle region.

Step-by-Step Solution

1
Identify seismic boundaries
Mohorovičić discontinuity separates crust from mantle, while Gutenberg discontinuity separates lower mantle from outer core.
Seismic velocity changes sharply at structural compositional transitions.
2
Distinguish physical state layers
Lithosphere is brittle/rigid outermost zone; Asthenosphere is ductile/semi-fluid underlying zone.
Mechanical properties differ based on temperature and pressure regimes.

Key Concept

Earth's Internal Discontinuities and Mechanical Spheres
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