There are three main types of rocks: igneous, sedimentary, and metamorphic. Igneous rocks form from the cooling and solidification of magma either below or above the ground. Sedimentary rocks form from the compression of sediments and organic materials. Metamorphic rocks form from the alteration of existing igneous and sedimentary rocks through heat, pressure, and chemical changes. Rocks continuously change between these forms through the rock cycle as they are weathered, buried deep underground, and altered by melting.

1. PRESENTED BY:
Halima khatun

2. ROCKS
• A rock is a naturally
occurring solid mixture of
one or more minerals, or
organic matter
• Rocks are classified by
how they are formed,
their composition, and
texture
• Rocks change over time
through the rock cycle

3. TYPES OF ROCKS

5. IGNEOUS ROCK
• Igneous rock begins as magma.
• Magma can form:
 When rock is heated
 When pressure is released
 When rock changes composition
• Magma is a mixture of many minerals

6. ORIGIN— Where rocks are
formed
• Below ground = from
magma (intrusive
igneous rock)
• Above ground = from
lava (extrusive
igneous rock)

7. IGNEOUS ROCK

8. SEDIMENTARY ROCK
• Sedimentary rock is
formed by erosion.
• Formed from
sediments (rock
fragments, mineral
grains, animal & plant
remains) that are
pressed or cemented
together.

9. TYPES OF SEDIMENTARY ROCK
• Clastic (also called
Detrial)—made of
broken pieces of
other rocks
• Organic—remains of
plants and animals
are deposited in
thick layers

10. TYPES OF SEDIMENTARY ROCK
• Chemical—minerals
dissolved in lakes,
seas, or underground
water
• E.g. Rock Salt—made
from evaporation of
sea waters

11. METAMORPHIC ROCK
• Rocks that have changed due to intense
temperature and pressure
• “Meta” means “change” and morphosis
means “form” in Greek
• Igneous, sedimentary and other metamorphic
rocks can change to become metamorphic
rocks

12. METAMORPHIC ROCK FORMATION
• Metamorphic rocks are
formed by heat and
pressure changing one
type of rock into
another type of rock.
• Metamorphic rocks
form near lava
intrusion, at plate
subdution zone and in
deep mountain roots.

13. METAMORPHIC ROCK

14. ROCK CYCLE
• Some igneous rocks are weathered and eventually buried
and converted into sedimentary (secondary) rocks.
• Other igneous rocks are transformed into metamorphic
(tertiary) rocks by heat, pressure and chemical change.
• Sedimentary and metamorphic rocks at the edges of the
tectonic plates are sub ducted back into the mantle, where
they are melted and can eventually be released as magma
and form new igneous rocks.
• Sedimentary rocks can be transformed into metamorphic
rocks by heat, pressure and chemical change.
• Metamorphic rocks can be weathered, buried and
converted into sedimentary rocks

15. ROCK CYCLE