Rocks form through three main processes: igneous, sedimentary, and metamorphic. Igneous rocks form when magma or lava cools and crystallizes. Sedimentary rocks form through the compaction and cementation of sediments over time. Metamorphic rocks were originally igneous or sedimentary rocks that were subjected to heat and pressure within the Earth, transforming their composition and structure.

1. FORMATION OF ROCKS
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2. WHAT IS A ROCK?
• Rock or stone is a natural
substance, a solid aggregate of
one or more minerals or
mineraloids.
• For example, granite, a common
rock, is a combination of the
minerals quartz, feldspar and
biotite.

3. THREE MAJOR WAYS OF
FORMATION OF ROCK
• Igneous rocks
• Sedimentary rocks
• Metamorphic rocks

4. IGNEOUS ROCKS
• Igneous rocks are rocks which
have crystallized from a melt or magma.
• The melt is made up of various
components of pre-existing rocks which
have been subjected to melting either
at subduction zones or within
the Earth's mantle.
• The melt is hot and so passes upward
through cooler country rock.
• As it moves, it cools and various rock types
will form through a process known
as fractional crystallization.
• Igneous rocks can be seen at mid ocean
ridges, areas of island arc volcanism or
in intra-plate hotspots.

5. SEDIMENTARY ROCKS
• Sedimentary rocks are formed through
the gradual accumulation of sediments:
for example, sand on a beach or mud
on a river bed.
• As the sediments are buried they get
compacted as more and more material
is deposited on top.
• Eventually the sediments will become
so dense that they would essentially
form a rock.
• This process is known as lithification.

6. METAMORPHIC ROCKS
• Metamorphic rocks are rocks which once
existed as igneous or sedimentary rocks
but have been subjected to varying
degrees of pressure and heat within the
Earth's crust.
• The processes involved will change the
composition and fabric of the rock and
their original nature is often hard to
distinguish.
• Metamorphic rocks are typically found in
areas of mountain building.

7. ROCK FORMATIONS
Bryce Canyon National Park The Wave

8. ROCK FORMATIONS
Yehliu Geopark Svartifoss

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