Question

Difficulty: MediumInternal and External Structure of the Earth

Match each layer or region of the Earth's structure listed in Column A with its correct physical property and composition in Column B.

  • SialLighter granitic continental crust predominantly composed of silica and alumina
  • SimaDense basaltic ocean floor layer composed predominantly of silica and magnesium
  • AsthenosphereSemi-fluid, plastic zone in the upper mantle that enables tectonic plate movements
  • BarysphereInnermost high-density metallic core consisting mainly of iron and nickel

Answer

Sial matches the lighter granitic continental crust (silica and alumina); Sima matches the dense basaltic oceanic crust (silica and magnesium); Asthenosphere matches the semi-fluid upper mantle zone enabling tectonic movement; Barysphere matches the innermost high-density metallic core (iron and nickel).
Sial is the lighter granitic layer rich in silica and aluminum forming continents. Sima is the denser basaltic layer rich in silica and magnesium forming ocean floors. The asthenosphere is the weak, semi-fluid region of the upper mantle supporting plate convection. The barysphere is the innermost heavy core composed of iron and nickel.

Step-by-Step Solution

1
Identify chemical compositions of the crustal layers
Sial stands for Silica + Alumina (continental), while Sima stands for Silica + Magnesium (oceanic).
Acronyms in physical geography directly correspond to dominant chemical elements in Earth's crust.
2
Analyze upper mantle mechanical properties
The asthenosphere is ductile and semi-fluid, located beneath the rigid lithosphere.
High temperatures allow asthenospheric rocks to slowly deform plastically, permitting lithospheric movement.
3
Classify the deep metallic interior
The barysphere refers specifically to the core region (Nife) composed of heavy metals like iron and nickel.
Barysphere originates from Greek root words implying 'heavy sphere'.

Key Concept

Internal Structure and Composition of the Earth
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