Structure of the Earth (Definition of Terms, Characteristics)

Topic Content:

The arrangement of the earth’s crust from the surface to the interior is;

• Sial
• Sima
• Mantle
• Core

The internal (or inner) structure of the Earth is made up of three concentric layers which are:

i. Crust (Lithosphere) – made up of the sial and sima

ii. Mantle (Mesosphere) and

iii. Core (Barysphere)

1. The Crust or Lithosphere:

The Crust is a thin layer of rocks and minerals, which lies above the Earth’s Mantle. This layer is composed of two types of crust; Oceanic and Continental.

The Oceanic crust is denser and thinner and mainly composed of basalt.  The Continental crust is less dense, thicker, and composed mainly of granite. It sustains life and forms the soil. It is divided into upper and lower parts, these are;

– The upper part of the earth’s crust forms the continents, it