ROCKS

1. POWER POINT
UNIT - IN SEARCH OF EARTH’S
SECRETS
LESSON - ROCKS
By,
Raji. R
Social science
Reg.no 16914303020

2. LITHOSPHERE AND ASTHENOSPHERE
 The crust and the upper part of the mantle
together are known as lithosphere.
 The part beneath the lithosphere, where the
materials exist in a partially molten state is
known as asthenosphere.
 This is the source of the molten rock material
(lava) that comes out during volcanic eruptions.

3. Rocks
 The lithosphere acquires its name from the
material with which it is made ('lithos' means rock).
 If you look around you can see rocks of different
colours and hardness. 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.

6. The rocks may not remain in their original form forever. They
are subjected to several changes over time. Observe the
diagram (Fig.3.3)