By Paige Black
Emily.black@smail.astate.edu
TYPES OF ROCK
WHAT ARE ROCKS?
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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
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Igneous Rocks
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Sedimentary Rocks
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Examples: granite, basalt, pumice, flint
Examples: limestone, chalk, sandstone
Metamorphic Rocks
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Examples: slate, marble, quartzite
IGNEOUS ROCKS
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These are rocks that solidified directly from magma.
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Magma can form:
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When rock is heated
When pressure is released
When rock changes composition
Magma freezes between 700˚C and 1,250˚C.
Magma is a mixture of many minerals.
IGNEOUS ROCKS
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Types of Composition:
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Felsic- light colored rocks that are rich in elements such as
aluminum, potassium, silicon, and sodium
Mafic- dark colored rocks that are rich in calcium, iron, and
magnesium, poor in silicon
Coarse-grained- takes longer to cool, giving mineral crystals
more time to grow
Fine-grained- cools quickly with little to no crystals
IGNEOUS ROCKS
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Types of Formation:
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Intrusive- magma pushes into surrounding rock below the
Earth’s surface
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Extrusive- magma erupts onto the Earth’s surface (lava),
cools quickly with very small or no crystals formed
SEDIMENTARY ROCKS
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The rocks are formed when igneous rocks are
eroded as a sediment under the sea.
Sediments are moved from one place to
another.
Sediments are deposited in layers, with the
older ones on the bottom.
The layers become compacted and cemented
together.
SEDIMENTARY ROCKS
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Three Types:
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Clastic- made of fragments of rock
cemented together with calcite or quartz
o
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Chemical- minerals crystallize out of
solution to become rock
o
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Example: Sandstone
Example: Halite (Rock Salt)
Organic- any accumulation of sedimentary
debris caused by organic processes
o
Example: Coal
METAMORPHIC ROCKS
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Means “change in form”
Changes with temperature and pressure, but
remains solid
Usually takes place deep in the Earth
Make up a lot of the Earth’s crust
METAMORPHIC ROCKS
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Two Types:
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Contact- when magma is injected into the surrounding rock
solid. Increased temperature changes the composition of
the rock, minerals are changed into new minerals.
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Regional- changes in great masses of rock over a wide area.
Large pieces of the Earth’s crust collide and the rock is
deformed and chemically changed by heat and pressure.
METAMORPHIC ROCKS
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Two Types of Texture:
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Foliated- contain aligned grains
of flat minerals
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Example: Slate
Non-foliated- mineral grains are
not arranged in bands or plains
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Example: Marble
3 TYPES OF ROCKS
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Igneous
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Sedimentary
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Metamorphic
RESOURCES
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http://jersey.uoregon.edu/~mstrick/AskGeoMan/geo
Querry13.html
http://en.wikipedia.org/wiki/Igneous_rock
http://en.wikipedia.org/wiki/Sedimentary_rock
http://en.wikipedia.org/wiki/Metamorphic_rock
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