earth, layers of earth, crust, mantle, core, lithosphere, rocks, type of rocks,weathering, soil

1. In search of earth’s secrets

2. The temperature and pressure inside the
Earth increases with depth. The
variations in pressure is due to the weight
exerted by the overlying layers. The
temperature at the centre of the Earth is
about 5000 c. remember that even iron
melts at 1538c.

4. The
comparati
vely thin
outer shell
of the
Earth.
Approxim
ately 40
km thick.
Two parts-
continenta
l crust,
oceanic
crust.
Located
beneath
crust.
Extends upto
2900 km
from the
crust.
Two parts-
upper
mantle,
lower
mantle.
Central
part of the
Earth.
From 2900
km to 6371
km.
Two parts-
outer core,
inner core.
CRUST MANTL
E
COR
E

5. The crust and the
upper part of the mantle
together are known as
lithosphere.
The part beneth the
lithosphere, where the
materials exist in a
partially motlen state rock
material (lava) that comes
out during volcanic
eruptions.

6. Rocks
The lithosphere acquires its
name from the material with
which it is made (litho means
rock). If you look arround you
can see rocks of different
colours and hardness.
.

7. This diversity is due to
its constituents. The
constituents of rocks are
called minerals. More than
two thousand minerals such
as silica, mica, hematite,
bauxite, etc have been
identified on Earth.
Based on the mode of
formation, rocks can be
classified into three-igneous,
sedimentary, and
metamorphic

8. Rocks
Igneous
rocks
Sedimentar
y rocks
Metamorph
ic rocks
Igneous rocks ; are formed
by the. molten rock material
rising through the fissures in
the crust and solidifying
either on the surface of the
Earth or within in the crust
itself. Eg; granite, blasat

9. Metamorphic rocks ; when rocks
undergo physical and chemical
changes due to high temperature
and pressure metamorphic rocks
are formed. Eg ; marble, slate.
Sedimentary rocks ; Rocks
undergo weathering in course of
time. The debris so formed will
be deposited in the low region as
layers. These materials gradually
get lithified and transformed into
sedimentary rocks. Eg ;
sandstone, limestone.

10. The rocks may not remain in their
original form forever. They are
subjected to several changes over
time. Observe the diagram.

11. weathering

14. Soil evolves

15. The soil today is formed by prolonged
processes like weathering of rocks and
decomposition of organic matter. It is
estimated that more than a thousand years is
required for the formation of an inch-thick
layer of soil.
Following diagram shows the factors
which influencing soil formation.

16. THANK YOU
RAHANA.N
K
KSTC