Standard Ninth Maharashtra Board Geography chapter 2 --> Interior of the Earth.

1. 2. INTERIOR OF THE
EARTH
GEOGRAPHY

2. Lets compare a COCONUT with our EARTH
We know that,
A coconut surface is hard so let’s call it
a “CRUST”
The soft white part , let’s
call it “MANTLE”
And this, let’s assume it
to be the core
Soft white part
“MANTLE”
Hard outer surface
“CRUST”
THE “CORE”

3. CRUST MANTLE
CORE
INNEROUTER

4. The Crust:
Crust is the uppermost layer of the earth
The crust is the thinnest of all layers when compared to the mantle
and the core
The crust is divided into two parts
> Continental crust
> Oceanic crust

5. Continentalcrust
The relatively thick part of the earth’s crust
which forms the large land mass is called the continental crust.
Granite rocks are mainly found in this layer.
The continents are mainly composed of Silica and
Aluminum.
Oceanic crust
The relatively thin part of the earth’s crust which
underlines the ocean basins is called the oceanic crust.
Basalt and gabbro rocks are mainly found in this layer.
It is made up of Silica and Magnesium.

6. The Mantle:
• Lies below the CRUST
Mantle
Upper
mantle
Lower
mantle

7. QUICK KNOWLEDGE:
Have you thought
Why the Himalayan range are so high
Or what causes the volcanos to erupt?

8. QUICK KNOWLEDGE:
All this is due to internal the
energy inside the earth.
This energy causes
movements leading to the
formation of mountains,
volcano, etc.
This movement is known as
ENDOGENIC MOVEMENT

9. Properties and characteristics
• Upper layer is more in liquid state.
• This liquid state is called MAGMA
• This layer is also known as ASTHENOSPHERE
• Mantle begins at the depth of 42km.
• When the depth reaches 2400km to 2900km
• The temperature rises between 2200o
to 2500o
UPPER MANTLE

10. Properties and characteristics
• The endogenic movements occurring in this
layer (The mantle) releases internal energy
• These movements cause the Mountain-
building
riffs, volcanic eruption, earthquake, etc.
• It is estimated that the mantle extends upto
a
a depth of 2870km
• Average density=4.5gm/cm
• The density increases with increasing depth
UPPER MANTLE
THE LOWE
MANTLE
HAS A DENSITY OF
5.7 gm/cm

11. The CORE
• The core starts from around the depth of about
2900km from the earth’s surface.
• The thickness of the core is about 341km.
CORE
OUTER CORE INNER CORE

12. Properties and characteristics
• The outer core is liquid or semi-liquid in nature .
• The secondary waves cannot pass-through the core.
• The secondary waves gets absorbed in this layer.
• The primary waves travel through this layer and when
passing, their speed decreases.
• It extends from around 2900km to 5100km.
• The temperature of the liquid is around 5000
o
C.
OUTER CORE

13. Properties and characteristics
INNER CORE
• The inner core is in solid state .
• Iron and nickel are the major elements found here
• The density of the inner core is around 13.3 gm/cm.
• It extends from around 5150km to 6371km.
• The temperature here is almost equivalent to the
surface temperature of the sun.