THE INTERNAL STRUCTURE OF THE EARTH

The internal or inner structure of the earth is made up of three concentric layers which are

• Crust ( lithosphere)
• Mantle (Mesophere)
• Core ( Barysphere)
  
  credit
  THE CRUST OR LITHOSPHERE

CHARACTERISTICS

The crust is sub-divided into upper and lower parts which are:-

• The upper part of the earth crust consist of granite rocks and forms the continent.
  The main minerals here are silica and aluminium collectively referred to as sial.
  The upper earth crust has average density of 27

• The lower part of the earth crust consists of basait rocks and aso form the ocean floor.
  The sial, therefore is lighter than the sima.
  The sial and sima 48km below the surface of the continent
  The lithosphere lies above the mantle
  The lower crust has a density of 3.0

THE MANTLE OR MESOSPHERE

CHARACTERISTICS

• The mantle is found just beneath the crust
  It is about 2897km thick
  It is very dense
  Its main minerals is olivine
  Its is plastic and in semi liquid form
  Has average density of about 3.3
  It is a middle layer which surround the one

THE CORE OR BARYSHPERE

CHARACTERISTICS

• The core is the innermost part of the earth.
  It is about 3476km in radius or width all around
  It contains two minerals, iron and nickel
  The temperature of the core is estimated to be as high as 2000c