Types of Rock

choppedspleenMechanics

Feb 21, 2014 (3 years and 5 months ago)

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Types of Rock

There are 3 types of rock:


Sedimentary

Metamorphic

Igneous

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Sedimentary Rock


Deposition

Small particles of rock formed by
weathering are transported into the sea
where they are deposited (sink) and
form a sediment.

At this stage dead creatures may
become trapped within the sediment
giving rise to fossils.

Over millions of years, the pressure of
the layers formed above and the
effects of salts cement the sediment
together to give sedimentary rocks like
sandstone and mudstone.

Fast flowing water

Slow water

Pressure

sedimentation

cementation

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Sedimentation + effects of pressure and minerals.


Layers of
sediments

getting older

Sedimentary Rock


Sedimentation

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Sedimentary Rock
-

Evaporation

Some sedimentary rock is formed in
a different way.

Certain minerals are dissolved in
seas and lakes.

Over millions of years these seas or
lakes have dried up.

As the water disappeared the
dissolved minerals precipitated.

Chalk and limestone, common in the
UK, are often formed in this way.

Dissolved minerals

Precipitation

Pressure

evaporation

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Sedimentary Rock
-

appearance

Sedimentary rocks consist of lots of
small particles and may be soft and
crumbly

They do not normally contain crystals
but may have
fossils

trapped within
them.

When viewing a whole cliff face of
sedimentary rock it is often possible to
see layers where slightly different
sediments have been deposited.

Sedimentary rocks consist of lots of
small particles.

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Sedimentary Rocks

sandstone

limestone

chalk

sandstone

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sandstone

orangey coloured rock

looks like lots of sand grains stuck together

quite soft

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limestone

grey/white coloured rock

mostly made from crushed sea
-
shells

may contain fossilised shells

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chalk

grey/white coloured rock.

mostly made from crushed sea
-
shells

may contain fossilised shells

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Match the rock with the description:

Rock

Picture

Sandstone

Limestone

Mudstone and shale

Chalk

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Metamorphic Rock
-

formation

Metamorphic rocks are formed by the effect of extreme
pressures and temperatures deep within the Earth.

This alters the structure of the existing rock.

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Metamorphic Rock
-

properties

They are usually denser and harder than
sedimentary rocks.

They often have
layer

structures of crystals
caused by the effect of heat and pressure.

They sometimes show distortions caused
by the movements that led to their
formation. This may give rise to wavy or
zig
-
zag patterns within the rock.

Regular layers of crystals that
sometimes also have a wavy or
zig
-
zag arrangement


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Metamorphic Rocks

marble

slate

Enlargements on next two slides
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marble

High temperatures cause the shells in limestone to break
down into crystals giving a harder smoother rock.

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slate

Pressure and some heat makes the particles in mudstone
line up in one direction. This makes a rock that can be
split into sheets.

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Which description goes with the rock?

Description

Rock

Dark grey rock used for roofing
because it is easily split into thin
layers.

Marble


Smooth, hard white rock often used
for kitchen cutting “boards.”

Mica


Transparent sheets are used as an
insulator in some electrical devices.
It is also ground up and used as a
“filler” in plastics, and cosmetics
such as lipsticks.


Slate


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Igneous Rocks
-

Formation

Deep within the ground is molten rock called magma.
Sometimes this bursts through the surface in the form
of volcanoes.

Igneous rocks are
formed when molten
magma cools and
solidifies.

This may happen within
the ground, or in the
case of volcano lava,
above ground.



magma

intrusive
igneous rock

extrusive
igneous rock

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Igneous Rocks


Rate of Solidification

The appearance of igneous rocks is
affected by how fast they cool.

Rocks formed within the ground are known as
intrusive igneous

rocks . They cool slowly
and this gives time for large crystals to grow.

Rocks formed once the magma has
burst through the surface are called
extrusive igneous
.

They cool quickly.

As a result crystals are much smaller.

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Igneous Rocks
-

intrusive

granite

A hard grey rock consisting of randomly arranged crystals.

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pumice

Extrusive igneous rocks, like pumice and basalt, do not have large
crystals and tend to be less dense than intrusive rocks like granite.

Igneous Rocks
-

extrusive

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basalt
-

pillars

Igneous Rocks
-

extrusive

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Igneous Rocks


Properties

Igneous rocks are hard.

They contain crystals. The the size of the crystals
depends on how quickly the rock solidified.

The crystals are disordered (unlike some
metamorphic rocks.)

They never contain fossils.

Igneous rocks consist of a
disorderly collection of crystals

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Am I igneous, sedimentary or metamorphic?


sedimentary

igneous (ext)

metamorphic

sedimentary

sedimentary

igneous (intr)

metamorphic

Type

I contain many fossils.

I am pumice.

My particles are arranged in bands
that are easily split apart.

I contain many small grains
“cemented” together.

I am mudstone.

I contain some really big crystals.

I am formed by heat and pressure.

Description

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Rock Formation

sea

volcano

Igneous rocks

basalt

Igneous rocks

granites

rocks rise

to surface by

uplift and erosion

rocks are broken

up by the action

of weather

magma

Metamorphic rocks
slate and marble

Sedimentary rocks

mudstone

slow

solidification

high pressure

and temperature

transportation

and deposition

rises to
surface

where it

cools
rapidly

melt

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Rocks take part in a rock cycle.


Molten ___________ solidifies at or near the
surface of the Earth to form ___________
rocks.


These undergo ___________ where they are
broken up by ___________ and chemical
processes.

magma

igneous

weathering

physical

Fill in the gaps in the sentences.

magma

igneous

weathering

physical

sedimentary

metamorphic

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The fragments of rock are carried to the
___________ by rivers. Here they sink and form
___________ rocks.


Over millions of years heat, ___________ and
movement may change these sedimentary rocks
into ___________ rocks. Some of these will
sink deep into the Earth and turn into
___________ and the cycle is repeated.


sea

sedimentary

pressure

metamorphic

magma

Fill in the gaps in the sentences.

magma

igneous

pressure

sea

sedimentary

metamorphic

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What type of rocks do these diagram represent?

igneous

metamorphic

sedimentary

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A

Intrusive Igneous

B

Extrusive Igneous

C

Metamorphic

D

Sedimentary


1. What type of rock is granite?

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A

Intrusive Igneous

B

Extrusive Igneous

C

Metamorphic

D

Sedimentary


2. What type of rock is slate?

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A

Intrusive Igneous

B

Extrusive Igneous

C

Metamorphic

D

Sedimentary


3. What type of rock is limestone?

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A

Intrusive Igneous

B

Extrusive Igneous

C

Metamorphic

D

Sedimentary


4. What type of rocks are pumice and basalt?

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A

Intrusive Igneous

B

Extrusive Igneous

C

Metamorphic

D

Sedimentary


5. What type of rock is mudstone?

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A

Pumice

B

Limestone

C

Slate

D

Granite


6. What type of rocks is made from
mudstone or shale?

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A

1

B

2

7. In this diagram showing a cross section of a
volcano, where would granite form?

1

2