Download What is the rock cycle?

Unit 4 Lesson 2 The Rock Cycle
Copyright © Houghton Mifflin Harcourt Publishing Company
Unit 4 Lesson 2 The Rock Cycle
Indiana Standards
• 7.2.2 Recognize that the earth possesses a
magnetic field that is detectable at the surface
with a compass.
• 7.2.5 Describe the origin and physical properties
of igneous, metamorphic and sedimentary rocks
and how they are related through the rock cycle.
Copyright © Houghton Mifflin Harcourt Publishing Company
Unit 4 Lesson 2 The Rock Cycle
Let’s Rock!
What is rock?
• Rock is a naturally occurring solid mixture of one
or more minerals and organic matter.
• Most rock is made of minerals, but some rock is
made of nonmineral material that is not organic,
such as glass.
• Rocks are always changing through time.
Copyright © Houghton Mifflin Harcourt Publishing Company
Unit 4 Lesson 2 The Rock Cycle
What processes change rock?
• Natural processes make and destroy rock. They
change each type of rock into other types of rock
and shape Earth’s features.
• Different natural processes influence the type of
rock that is found in each area of Earth’s surface.
Copyright © Houghton Mifflin Harcourt Publishing Company
Unit 4 Lesson 2 The Rock Cycle
What processes change rock?
• Water, wind, ice, and changes in temperature can
change rock in a number of ways.
• Weathering is the process by which rock is
broken down by water, wind, ice, and changes in
temperature.
Copyright © Houghton Mifflin Harcourt Publishing Company
Unit 4 Lesson 2 The Rock Cycle
What processes change rock?
• Erosion is the process by which sediment is
moved from one place to another.
• Sediment comes to a rest in a process called
deposition.
Copyright © Houghton Mifflin Harcourt Publishing Company
Unit 4 Lesson 2 The Rock Cycle
What processes change rock?
• Heat and pressure can change rock.
• Rock that is buried can be squeezed by the weight
of rock or layers of sediment on top.
• With enough temperature and pressure, buried
rock can change into metamorphic rock.
Copyright © Houghton Mifflin Harcourt Publishing Company
Unit 4 Lesson 2 The Rock Cycle
What processes change rock?
• In some cases, the rock gets hot enough to melt
and form magma, or molten rock.
• If the magma reaches Earth’s surface, it is called
lava.
Copyright © Houghton Mifflin Harcourt Publishing Company
Unit 4 Lesson 2 The Rock Cycle
Classified Information!
What are the classes of rocks?
• Igneous rock forms when magma cools and
hardens.
• Sedimentary rock forms when sediment from
older rocks gets pressed and cemented together.
• Metamorphic rock forms when pressure,
temperature, or chemical processes change
existing rock.
Copyright © Houghton Mifflin Harcourt Publishing Company
Unit 4 Lesson 2 The Rock Cycle
What are the classes of rocks?
• The three types of sedimentary rocks are clastic,
chemical, and organic.
• Clastic sedimentary rock forms when layers of
sediment are compacted to form solid rock.
• Chemical sedimentary rock forms when dissolved
minerals come out of a solution.
• Organic sedimentary rock is made of the remains
of ancient organisms.
Copyright © Houghton Mifflin Harcourt Publishing Company
Unit 4 Lesson 2 The Rock Cycle
What are the classes of rocks?
• Igneous rocks can be classified as intrusive or
extrusive.
• Intrusive igneous rocks form when magma cools
and hardens beneath Earth’s surface.
• Extrusive igneous rocks form on Earth’s surface
when lava cools and hardens.
Copyright © Houghton Mifflin Harcourt Publishing Company
Unit 4 Lesson 2 The Rock Cycle
What are the classes of rocks?
• Metamorphic rock is classified by whether or not
the minerals form distinct layers or bands.
• Foliated metamorphic rocks form when mineral
grains in the rock are arranged in layers.
• Nonfoliated metamorphic rocks do not have
distinct bands.
Copyright © Houghton Mifflin Harcourt Publishing Company
Unit 4 Lesson 2 The Rock Cycle
Rock! ‘n’ Roll
What is the rock cycle?
• Any of the rock types can be changed into another
of the three types.
• The series of processes in which rock changes
from one type to another is called the rock cycle.
• A rock’s identity can be changed by factors such
as temperature, pressure, weathering, and
erosion.
Copyright © Houghton Mifflin Harcourt Publishing Company
Unit 4 Lesson 2 The Rock Cycle
What is the rock cycle?
• Igneous rock that is exposed can break down into
sediment.
• Igneous rock beneath Earth’s surface can change
into metamorphic rock.
• Heat and pressure can change sedimentary rock
into metamorphic rock.
• Metamorphic rock can melt and form magma.
Copyright © Houghton Mifflin Harcourt Publishing Company
Unit 4 Lesson 2 The Rock Cycle
What is the rock cycle?
• Describe what happens in each part of the rock
cycle.
Copyright © Houghton Mifflin Harcourt Publishing Company
Unit 4 Lesson 2 The Rock Cycle
How do tectonic plate motions affect
the rock cycle?
• Tectonic plate motions can move rock around,
exposing it to different conditions.
• Uplift is the rising of regions of the crust to
higher elevations, causing more erosion.
• Subsidence is the sinking of regions of the crust
to lower elevations, causing basins where
sediment is deposited.
Copyright © Houghton Mifflin Harcourt Publishing Company
Unit 4 Lesson 2 The Rock Cycle
How do tectonic plate motions affect
the rock cycle?
• Tectonic plate motions can pull apart Earth’s
surface, creating new surfaces that can be eroded.
• A rift zone is a set of deep cracks that forms
between two tectonic plates that are pulling apart.
Copyright © Houghton Mifflin Harcourt Publishing Company
Unit 4 Lesson 2 The Rock Cycle
Cliff Dwellings
• Ancient people used rock for their shelter and art.
Some of the works they produced in rock are still
seen today.
• The ancient Puebloans in Colorado constructed a
castlelike dwelling known as the Cliff Palace.
• Another group of ancient people carved an
elaborate castlelike dwelling in a wall of rock in
Jordan.
Copyright © Houghton Mifflin Harcourt Publishing Company