Mountains, valleys, plains and plateaus
are the major land form features found on the earth's surface.
But what is inside the earth?
Let's go into the video.
We can use the structure of an onion as an analogy
to learn the interior of the earth
Earth is
made of different layers like an onion.
The outermost layer is called the crust.
Unlike onion
layers, the crust is not uniformly thick.
Thickness of the crust varies from 5 kilometers
to 70 kilometers.
It is thin
under oceans and thick under the continents.
Especially in mountain regions like the Alps
and
the Himalayas, the thickness will be very high.
The mantle is the next layer found below the crust.
It is found upto the depth of 2900 kilometers.
The
mantle is composed of silicate rocks that
are rich in magnesium.
These semi molten rock
materials are called magma.
The mantle is divided into outer mantle
and inner mantle.
The top
most part of the mantle is relatively weak.
This weak layer of the mantle is called the
asthenosphere.
The crust and uppermost layer of the mantle
form the lithosphere.
Its thickness
varies from 10 kilometers to 200 kilometers.
The core is the next layer found below the mantle.
The core is made of heavy metals like nickel
and iron
with iron constituting around 80% of the core.
Outer core, which is in liquid state
extends from the depth
of 2900 kilometers to the depth of 5100 kilometers.
Inner core which is in solid state
extends from the depth
of 5100 km to the depth of 6400 km approximately
The transition zone between different layers is called
discontinuity in geological studies.
Mohorovic discontinuity is found between
the crust and the mantle.
Gunternberg discontinuity is
found between
the mantle and the core.
Kola super deep borehole, located in Russia
is the
deepest point reached from earth surface by drilling.
And, it measures around 12.2 kilometers.
Thank
you for watching this video
