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Zorluk: OrtaInternal and External Structure of the Earth

The Earth's outer crust is divided into continental and oceanic layers based on density and mineral composition. Which of the following statements correctly describes the sial layer of the Earth's crust?

  1. A
    It forms a continuous layer under the ocean floors composed mainly of basaltic rocks created through marine sediment deposition.
  2. It forms the lighter upper continental crust composed predominantly of silica and aluminium, floating above the denser sima layer.Cevap
  3. C
    It consists of loose surface debris moved down slopes under the direct force of gravity across continental margins.
  4. D
    It represents the dense metallic core of the Earth dominated by molten iron and nickel below the mantle.

Cevap

The sial layer forms the lighter upper continental crust composed predominantly of silica and aluminium, floating above the denser sima layer.
The sial layer forms the discontinuous outer layer of the Earth's crust found mainly on continents. It is composed chiefly of granitic rocks rich in silica and aluminium, with a lower density that allows it to float upon the continuous, denser sima layer underneath.

Adım Adım Çözüm

1
Identify the chemical composition and position of the sial layer.
Sial derives its name from Silica (Si) and Aluminium (Al) and makes up the upper continental crust.
Geophysical composition divides the outer crust into upper sial and lower sima.
2
Compare the density of sial relative to sima.
Sial has an average density of about 2.7 g/cm³, making it lighter than the underlying sima (density ~3.0 g/cm³).
Due to its lower density, continental sial floats upon the denser basaltic sima layer.

Anahtar Kavram

Chemical zonation of the Earth's crust (Sial vs. Sima)
Tahmini Süre:1m 0s
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Konular

Internal and External Structure of the Earth

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