Rocks

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ROCKS

• Presentation by SRESTHO

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WHAT ARE ROCKS?
A rock is any naturally occurring solid mass or
aggregate of minerals or mineraloid matter. It is
categorized by the minerals included, its
chemical composition and the way in which it is
formed. Rocks are usually grouped into three main
groups
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WHAT ARE ROCKS MADE OF?
. Rocks are made of minerals, like quartz,
calcite, feldspars, and micas. Most rocks are
made from more than one mineral, but there are
quite a few kinds that are made from only one
mineral. Minerals are not rocks, rocks are made
of minerals.
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TYPES OF ROCK

• IGNEOUS ROCKS
• SEDIMENTARY ROCKS
• METAMORPHIC ROCKS

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WHAT IS A ROCK CYCLE
The rock cycle is the process by which rocks of
one kind change into rocks of another kind. There
are three main kinds of rocks igneous rock,
metamorphic rock, and sedimentary rock. Each of
these rocks can change into the other kinds by
physical processes cooling, melting, heat,
weathering / erosion.
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IGNEOUS ROCKS
Igneous Rock is formed when a magma cools
underground or when it erupts unto the surface
of the ground, cools . Magma that erupts onto the
surface is called lava. When magma cools slowly
underground the crystals are large enough to see.
When it cools quickly on the surface, the
crystals are very small and you would need a
magnifier or a microscope to see them. Sometimes,
when the magma cools very quickly, it forms a
kind of black glass that you cannot see through.
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TYPES OF IGNEOUS ROCKS

• Intrusive igneous rocks-Intrusive igneous rocks
  forms when hot molten lava cools below the
  earths surface. It is slow to cool, when it
  finally hardens it is intrusive igneous rocks.
• Extrusive igneous rocks-Extrusive igneous rocks
  forms when in which hot magma from inside the
  Earth flows out (extrudes) onto the earths
  surface and when it cools down it becomes
  extrusive igneous rocks.

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SEDIMENTARY ROCKS
Sedimentary Rocks can be formed in different
environments at the surface of the earth or
within water bodies. Some rocks are formed as
chemicals precipitate from seawater, or through
accumulation of organic material such as animal
shells or plant debris.
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METAMOPHIC ROCKS
Metamorphic Rock is formed by great heat, or
pressure, or both. The pressure can come from
being buried very deep in the earth's crust, or
from the huge plates of the earth's crust pushing
against each other. The deeper below the surface
of the earth, the higher the temperature, so deep
burial also means high temperatures. Another way
that high temperatures occur is when magma rises
through the earth's upper crust. It is very hot
and bakes the rock through which it moves. Hot
liquids or gases from the magma also can cause
chemical changes in the rock around the magma.
The process of metamorphic rocks takes more than
1000 years
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THE ENDI HOPE YOU LIKED THE PRESENTATIONTHANKYOU