How are these like the mantle?
Convection Currents!
Hot magma rises towards the crust, cooler magma sinks towards the
core, and heats up again. This creates a circular movement that moves
the oceanic crust and continental crust above.
Convection Current Animation:
What do you observe?
http://education.sdsc.edu/optiputer/flash
/convection.htm
Oceanic vs. Continental Crust
Introductory Video
https://www.youtube.com/watch?v=HrKTuCDierM
https://www.youtube.com/watch?v=HrKTuCDierM
3 Types of Boundaries
What are the differences
between these pictures?
3 Types of
Boundaries Notes
Transform Boundary
Divergent Boundary
Convergent Boundary
Transform Boundary
Boundary where plates slide
past each other.
Hint: A way, or hint, to remember this is the
word TRAINS. TRAINS and TRANSform are very
similar words. Think of 2 trains that travel on
different tracks that are parallel to each other. They
don’t collide, but slide past each other in opposite
directions, just like the plates at a transform
boundary.
Transform Boundary
Draw this picture in the “Picture
box.”
Fault
Earthquakes
Transform boundary:
- boundary where plates
slide past one another.
- Faults form at these
boundaries
Transform boundary:
Transform Boundary
Events that happen at this
boundary:
Earthquakes
Transform Boundary
Geographic Features that
happen at this boundary:
Fault
How does an earthquake
happen at a transform
boundary?
When plates slide past each other,
pressure is applied to the rock and
builds up. When enough pressure
builds up, huge areas of rock
suddenly shift or break, causing an
earthquake.
Fault
A fault is a crack in Earth’s
crust where movement
occurs (usually just at a
transform boundary).
Earthquake
Shaking of the ground due
to built up pressure
suddenly releasing, causing
the ground to shake.
Convergent Boundary
HINT: CONvergent is where
plates COMe together.
1. Convergent Boundary:
continental-continental
Boundary where 2
continental plates collide.
Since neither can sink, they
push up as they collide.
Draw the following picture in the
“picture” box for continentalcontinental.
Convergent; continental-continental
1. Convergent Boundary:
continental-continental
Events:
• Earthquakes
1. Convergent Boundary:
continental-continental
Geographic Features
• Mountain ranges: formed
by colliding plates pushing
rock upward for millions
of years.
2. Convergent
Boundary:
continental-oceanic
3. Convergent Boundary:
continental-oceanic
Where an oceanic plate and
continental plate meet. The
oceanic crust sinks under
the continental crust, going
into the mantle.
Draw the following picture
in the “Picture” box.
Trench
Earthquakes
Convergent Boundary:
continental-oceanic
Events:
• Earthquakes
• Crust is destroyed (melts
into magma)
• Oceanic crust subducts
Convergent Boundary:
continental-oceanic
Geographic Features
•
•
•
Volcanoes/volcanic mountains
Trench
Subduction zone
Convergent Boundary:
continental-oceanic
Use the following slides to
find the vocabulary words
for the definitions on your
sheet.
Convergent; oceanic-continental
http://www.scec.org/education/k12/learn/plat
e4.htm
Convergent: OceanicContinental
Convergent boundary:
http://geology.com/nsta/convergent-boundary-oceanic-continental.gif
How do volcanoes happen?
Subduction forms a trench & the area around the trench is
called the “subduction zone.”
As the oceanic plate is
pushed under the
continental, it is pushed
deeper into the Earth &
begins to melt. The
melted rock reaches the
surface through
volcanoes.
Volcano:
An opening in Earth’s crust through
which melted rock, gases, and ash can
be released.
Are created when an oceanic plate is
pushed under the
continental & begins to
melt. The melted rock
reaches the surface
Volcanic Mountains
-The subduction forces melted rock up
through the crust, where it hardens.
-Over time the igneous
rock builds up, forming
volcanic mountains.
These can be on the
continent or on the
ocean floor.
3. Convergent
Boundary:
oceanic-oceanic
3. Convergent Boundary:
oceanic-oceanic
Boundary where 2 oceanic
plates collide. The more
dense plate slides under the
less dense plate.
Draw the following picture
in the “picture” box.
Trench
Earthquakes
Convergent; oceanic-oceanic
http://www.scec.org/education/k12/learn/plat
e4.htm
Convergent; oceanic-oceanic
http://www.scec.org/education/k12/learn/plat
e4.htm
3. Convergent Boundary:
oceanic-oceanic
Events:
• Earthquakes
• Crust is destroyed (melts
into magma)
• Oceanic crust subducts
3. Convergent Boundary:
oceanic-oceanic
Geographic Features:
• Volcanic island arc
• Volcanic islands
• Underwater volcanoes/volcanic
mountain
• Subduction zone
• trench
Use the following slides
to find the vocabulary
words for the definitions
on your sheet.
They are not necessarily
in order.
Read carefully.
Underwater volcanoes/volcanic
Underwater
mountain:
volcano
As the subducting plate melts,
the magma rises to the ocean
floor, cools &
hardens. As it
piles up, these
are created.
Volcanic Island:
Over more time, the volcanic
Volcanic
mountains underwater grow tallIsland
enough to rise
out of the
water and
form volcanic
islands.
Volcanic Island Arc:
An arch- shaped mountain
belt made of only
volcanoes.
Volcanic
Island Arc
Trench:
Crack between plates at a
convergent boundary. Where the
plates come together and
Trench
subduction happens.
Trench
Volcanic
Island Arc
2. Convergent Boundary: oceanic-oceanic
Subduction: process of an
oceanic plate sliding
under another plate.
Subduction Zone:
Place where an oceanic
plate slides under another
plate.
Subduction
Zone
Divergent Boundary
Where plates move away
from each other.
Divergent
Boundary
Divergent Boundary:
Draw the following picture
in the “Picture” box.
Rift valley where magma is
Mid-ocean ridge
Divergent: Oceanic-Oceanic
Divergent Boundary:
Events:
• earthquakes
• New crust is created
• Sea-floor spreading
Divergent Boundary:
Geographic Features
•
•
•
Mid-ocean ridge
Rift
Rift valley
Divergent Boundary:
Use the following slides to
fill in the vocabulary words
for the definitions in your
notes.
Divergent Boundary:
Mid-ocean ridge
Rift valley
Mid-ocean ridge:
Lava comes out of the rift,
gradually hardening into
rock to create an
underwater chain of volcanic
mountains on either side of
the rift.
Rift:
Crack between plates
through which melted
rock rises up to form
new crust.
Rift valley:
Rift in the valley
between the mountains.
Sea-floor spreading:
When melted rock rises
through rifts on the sea floor
and creates new oceanic
crust, it pushes the older
crust away from the rift. The
older crust is eventually
destroyed at a convergent
boundary.