Grade 9 Natural Science

1. LESSON 4
ROCKS

2. Types of rocks in the Lithosphere
There are THREE rock types:
1.Igneous rocks e.g. Granite
2.Sedimentary rocks e.g. Sandstone
3.Metamorphic rocks e.g. Marble

3. 1) Igneous rocks
The temperature in the mantle is extremely high and is
hot enough to melt rocks.
When the rocks melt they form molten rock (thick liquid)
called magma.
When the magma cools down it forms igneous rock.
Examples of igneous rocks are basalt and granite.

4. Molten rock called magma

5. Granite mining

6. Igneous rocks

7. 2) Sedimentary rocks
Rivers and wind can transport tiny fragments of rock called
sediments.
When sediments are deposited into shallow lakes or
oceans, they form layers.
Over millions of years the layers of sediments harden and
form sedimentary rock.
Examples: chalk, limestone, sandstone and shale.
Sedimentary rocks may contain fossils of animals and
plants.

9. 3) Metamorphic rocks
Rocks which are exposed to the extreme pressures of moving tectonic
plates, or extreme temperature of magma, can undergo chemical changes
which changes their mineral structure.
Examples of metamorphic rocks are marble and slate.

10. Properties of each type of rock :

11. THE END