Geography Series - 5

Hey Guys, today we’ll have learn about Interior of Earth.

1)    The Crust : mainly SiAl (Silica + Aluminium)

·       Outermost solid part of the earth., brittle in nature

·       Thickness of crust more at continental areas (it is around 30 Kms) than at oceanic areas (where it is around 5 km).

·       At major mountains, thickness is as high as 70 Kms.

·       Rock density is around 3 g/cm³ in continent areas.

·       At oceanic area, rock is mainly basalt with density around 2.7 g/cm^3.

2)    Mantle: mainly SiMa (Silica + Magnesium)

·       Portion of interior beyond crust.

·       Extends from Moho’s discontinuity to depth of 2900 Kms.

·       Upper portion of Mantle is called asthenosphere (astheno means weak) – depth upto 400 Kms; main source of magma; density (3.4 g/cm³ ) more than crust.

·       Crust + upper mantle = lithosphere (its thickness ranges from 10-200 km).

·       Lower Mantle – beyond asthenosphere and is in solid state.

3)    The Core: mainly NiFe (Nickel + Iron)

·       Core-Mantle boundary located at 2900 km depth.

·       Outer core is in liquid state while inner in solid state.

·       Density at core mantle boundary is around 5g/cm³ & at centre is around 13g/cm³

^{There are zone of separation also known as discontinuities between above layers (i.e. Core, Mantle and Core) which are as under:}

 

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• ·     Magnetic property of Earth is due to outer core. Outer core rotates. Magnetic property helps in saving earth life. Why?? (I want answer from you guys)
  
  
  ·       As depth inside earth increases, pressure increases, temperature increases, Density increases.
  
  
  This was about the interior of earth. It’s good to remember discontinuity names as they may sometimes be asked directly in the examination.

 In the next article, we will study about different types of rocks.

Let us know how you are finding the series and there is always a scope for improvement. So, do tell us how we can further improve.

 Ciao !