ACTIVITY 9.2 ͵ FILLING OUT THE SUMMARY CHART
What Will We Do?
We will synthesize and organize the concepts and processes we have been learning to better
understand plate tectonics.
Procedure
Complete the summary chart. You will find it helpful to use the word/concept bank (Activity
9.1) and cross section (Activity Sheet 9.1) that you have already created. Be as descriptive
and detailed as possible.
Convergent
Subduction
Convergent Collision Transform
No volcanoes
No volcanoes
Volcanoes
Volcanoes form on the
continental plate, in a line
parallel to plate boundary.
Earthquakes
Earthquakes under the
surface following the
subducting plate
Many earthquakes as
plates collide and crumple
Many earthquakes as
plates scrape alongside
each other
Trenches
Trench in ocean running
parallel to plate boundary
No trenches
No trenches
DirecƟon of
Movement
Plates moving toward each Plates moving toward each Plates moving alongside
other
other
each other
Type of Plates
(Oceanic or
ConƟnental)
Both. Oceanic plate
subducts underneath
continental plate.
Two continental plates
Two continental plates or
two oceanic plates
Highest mountains in
world at this boundary
No mountains
Mountains
Mountains form on the
continental plate in a line
parallel to plate boundary
(volcanoes if active).
LESSON 9: WHAT DO WE KNOW ABOUT PLATE TECTONICS? 63
Convergent
Subduction
Convergent Collision Transform
No islands
No islands
No islands
Thin oceanic plate
Two thick continental
plates
Two thin oceanic plates or
two thick continental
plates
Density of Rocks
Thin oceanic plate has
higher density than thick
continental plate.
Two thick continental
plates with lower density
Oceanic plates are higher
density than continental
plates.
No ocean floor involved
No new ocean floor
New Ocean Floor
No new ocean floor
formed (ocean floor is
being recycled).
Islands
Thin or Thick Plates
Thick continental plate
Other
Making Sense
Use the drawings of boundary types to answer the following questions.
1. Which cross section(s) represent a convergent boundary? What makes the three cross
sections different?
A convergent boundary is shown in cross sections A, B, C. The three cross sections differ in the
types of plates that are moving toward each other.
Cross section A: Oceanic plate material is moving toward continental plate material.
Cross section B: Two slabs with oceanic plate material are moving toward each other.
Cross section C: Two slabs with continental plate material are moving toward each other.
64 HOW IS THE EARTH CHANGING?
Volcanoes form on the
continental plate in a line
parallel to plate boundary.
Earthquakes under the
surface following
subducting plate.
Trench forms as one
plate subducts beneath
another, runs parallel to
plate boundary.
Volcanoes form
immediately above
hot spot.
Volcanoes form as
magma erupts through
continent.
Volcanoes sometimes form as
islands formed.
Not common
Not common
Earthquakes directly tracing
plate boundary.
No trenches
No trenches
No trenches
Plates moving towards
each other.
One plate moving
over fixed hot spot.
Plates moving
away from each
other.
Two oceanic plates.
Either one
continental plate or
one oceanic plate.
One continental
plate.
No mountains.
Mountains (active
volcano immediately
above hot spot).
Islands form on
one plate as other
plate subducts
Islands form if
hotspot is
beneath oceanic
plate.
No mountains
No islands
Plates moving away from
each other.
Two oceanic plates.
Mountains ridge at
spreading center
Islands can form
if magma rises to
surface of ocean
and solidifies.
Two thin oceanic
plates.
One thin oceanic
plate or one thick
continental plate.
One think
continental plate.
Two thin oceanic
plates.
Two higher density
oceanic plates.
Oceanic plate is
higher density.
Continental plate
is lower density.
One lower density
continental plate.
Two higher density
oceanic plates.
No new ocean floor
formed.
New ocean floor
created as continents
split apart.
New ocean floor created at
spreading center.
No new ocean floor
formed.