Transcript The Rock Cycle

The Rock Cycle
 Once
igneous, metamorphic, and
sedimentary rocks are formed, do
they stay in the same form
forever?
No, rocks can change over time
Igneous rock can change into
sedimentary rock or into
metamorphic rock.
 Sedimentary rock can change into
metamorphic rock or into igneous
rock.
 Metamorphic rock can change into
igneous or sedimentary rock.

In other words…
 Any
rock can become any
other kind of rock.
 What causes these changes
to happen?
Two major processes cause
rocks to change:
1.
Plate Tectonics
2. Weathering & Erosion
Plate Tectonics Review

According to Plate Tectonic Theory, the surface
of the Earth is broken into large plates.
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The position of tectonic plates
changes over time. Plates are in
constant motion.
The edges of these plates, where
they move against each other, are
sites of intense geological activity,
such as
 Earthquakes & volcanoes
 Subduction (as rocks move deeper
they undergo heat and pressure)
 Uplift (such as mountain building)

Erosion is
another
major
process that
modifies the
earth’s
surface.
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What causes erosion?
 Wind, Water, and Gravity
With time, erosion breaks down all the
rock material at the earth’s surface and
redistributes it, carrying it to other
places.
The eroded rock pieces, called
sediments, drop from the wind or water
to make a layer. This is called
deposition because the sediments have
been “deposited” on the bottom of a
river or on the ocean floor or on land.
Compaction and Cementation
 When
the deposited layers
gets buried under other layers
of sediment, they go through
compaction and cementation
(also known as “lithification”)
becoming sedimentary rock.
Sedimentary Rock Layers
Grand Canyon National Park
Sedimentary Rock
Sandstone, Lower Antelope Canyon, Arizona
IGNEOUS ROCK
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Igneous rock forms when magma cools
and makes crystals.
Magma is a hot liquid made of melted
minerals. When it pours out on Earth's
surface, magma is called lava. The
minerals can form crystals when they cool.
Igneous rock can form underground,
where the magma cools slowly. This forms
intrusive igneous rocks.
Or, igneous rock can form above ground,
where the magma cools quickly. This
forms extrusive igneous rocks.
Intrusive Igneous Rocks
Gabbro
Granite
Extrusive Igneous Rocks
Obsidian
Pumice
Rhyolite
METAMORPHIC ROCK
Metamorphic rocks are formed by heat
and pressure.
 Heat “bakes” the rock. The rock does
not melt, but it does change. It forms
crystals, and if it has crystals already, it
forms larger crystals.
 Because this rock changes, it is called
metamorphic.
 Metamorphosis can occur in rocks when
they are heated to 300 to 700 degrees
Celsius.

Metamorphic Rocks
Marble
Migmatite
Gneiss
pronounced “nice”
THE ROCK CYCLE
 Landforms
made of metamorphic
rocks and igneous rocks can be
broken up and washed away by
streams through erosion.
 New sediments from these
landforms can make new
sedimentary rock.
 The
rock cycle never stops.
Color-Code your Diagram
 Color
the product ovals (what
the rock becomes) YELLOW
 Circle the 3 main types of
rock in RED
 Underline the processes (what
happens to the rock) in GREEN
DIAGRAM QUESTIONS
Examine your Rock Cycle diagram.
With your partner, answer the following questions on a sheet of
lined paper.
1. List the 3 processes that igneous rock can experience (follow
the arrows).
2. List the 3 processes that metamorphic rock can experience.
3. List the 3 processes that sedimentary rock can experience.
4. What type of rock does magma become?
5. What types of rock can become sediment?
6. Describe a path that sedimentary rock can follow to become
igneous rock? Use arrows.
Refer to your diagram to answer the following questions:
7. Metamorphic Rock goes through ___________________
to become Magma.
8. Magma undergoes _____________________________
and __________________________ to become Igneous
Rock.
9. Igneous Rock experiences ________________________
to become Sediment.
10. Sediment goes through the processes of
_______________ and _________________to become
Sedimentary Rock.
11. Sedimentary Rock undergoes _______________________
to become Metamorphic Rock.
12. Write down two DIFFERENT paths that an igneous rock
could take to become an igneous rock in the future.
Include the names of all the steps it goes through in each
path.
Resources
http://www.cotf.edu/ete/modules/msese/ea
rthsysflr/rock.html