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Rocks
Chapter 3
Earth’s Surface
Rock Cycle
3.1
Rocks are made of minerals
 Rock
– a naturally formed solid that is
usually made up of one or more types of
minerals.
 Rocks
and minerals are different!
 Minerals are always made of the same
elements in the same proportions.
 Rocks do not have to have the same
elements and proportions.
Rocks are all around
 Earth
is built almost entirely of rock.
 Below the crust, Earth is made of solid and
molten rock.
 Rocks can change, but this is a long slow
process.
Rock Cycle
 Rock
Cycle – the natural process that
form, change, break down and re-form
rocks.
 There is no beginning and end to the
cycle.
 There is no particular order, rocks can go
back and forth between processes.
Rock Types
 Igneous
Rock – forms when molten rock
cools and becomes solid.
 Sedimentary Rock – forms when pieces of
older rocks, plants and other material get
pressed or cemented together.
 Metamorphic Rock – forms when heat or
pressure causes older rocks to change
into new types of rocks.
Rock Cycle
 Fill
in the blanks on the rock cycle
handout.
 Check
 Paste
that you filled it out correctly!
the completed rock cycle into your
science notebook.
Igneous Rocks
3.2
Magma and Lava form
different igneous rocks
 Igneous
rocks form when molten rock
cools and becomes solid.
 Magma is molten rock inside Earth.
 Lava is molten rock at Earth’s surface.
 Igneous
rocks are classified based on their
mineral composition and crystal size.
Origin of Igneous Rocks:
(where they form)
 Intrusive
igneous rock – forms when
magma cools inside the Earth
 Extrusive
igneous rock – forms when lava
cools on Earth’s surface
Textures of Igneous Rocks
 The
texture of an igneous rock depends
on how quickly the magma or lava cools.
 Texture is the size of the mineral crystals.
 Slow
cooling allows time for crystals to
form. Intrusive
 Fast cooling leaves no time for crystals to
form. Extrusive
Composition of Igneous Rocks
 Most
igneous rocks are made up of
silicate minerals.
 Remember silicate minerals are the most
common group in Earth’s crust.
 Igneous
rocks high in silica are light in
color.
 Igneous rocks low in silica are dark in
color.
Intrusive
 Formed inside crust
 Large crystals due
to slow cooling
Extrusive
 Formed at surface
 Small crystals due
to fast cooling
Review and compare
High Silica
 Light in color
 Granite and
ryholite
Low Silica
 Dark in color
 Basalt and gabbro
Review and compare
Igneous rocks last a long time
 Intrusive
 As
Rock formations
magma pushes up toward Earth's
surface, it makes channels and other
formations underground. Igneous
rock can be left at the surface as other,
weaker types of rock have been worn
away.
Igneous rocks last a long time
 Extrusive
 Lava
Rock Formations
that is low in silica, such as basalt
lava, flows easily and spreads out in thin
sheets over great distances.
 Lava with more amounts of silica does not
flow easily and tends to volcanoes with
steep sides.
Hypothesis writing
 If
20 mL of water are put in 4 different
containers
 Then the water from the ________________
will evaporate the fastest
 Because ________________________
Sedimentary Rocks
3.3
 Materials
that make up sediments
 3 Groups of Sedimentary Rocks

The processes that form Sedimentary Rocks
 Sedimentary
 This
Rocks record the past
is the outline for the notes Do not write
it yet
Materials that makeup
Sediments
 Sediments
– materials that settle out of
water or air
1. Pieces of rocks
2. Pieces of minerals
3. Plant remains
4. Animal remains
Sediments
 Sediments
are the small particles that
form together to make sedimentary rocks
 Are the result of weathering and erosion
 Can be transported by wind and water
Groups of Sedimentary Rocks
A.
Rock Particles
1.
Pressure – layers of sediment get pressed
together to form rock
Older layers are at the bottom
2.
Crystalized minerals cement particles
together
Groups of Sedimentary Rocks
B.
Plants or shells get pressed together
1.
2.
Coal – made of plant remains
Limestone – made of shells of ocean
organisms
Groups of Sedimentary Rocks
C.
Minerals re-form from water


When water evaporates minerals are left
behind
Rock salt and gypsum are examples
Recording the past
 Fossils
 Evidence
of wind and water in the past
Metamorphic Rocks
3.4