Transcript What happens when two tectonic plates come together?

What happens when two
tectonic plates come together?
AKS 17b2
Deformation
• The process by which a rock changes shape.
The forces are called stress.
Three ways it can change
1 – compression is the stress when an object is
squeezed
2- tension is the stress that occurs when an
object is stretched
3 - shearing is the stress when objects push past
each other.
Boundary
• A place where tectonic plates touch. Stress
occurs here
• Three types of boundaries–
Divergent – pulls apart
Convergent – pushes together
Transform – slides beside
Using your hands demo
Divergent – move hands apart
Convergent – move hands together
Transform – move hands back and forth
Practice plate boundaries!
Practice
Practice
1 = convergent, 2 = divergent, 3 =
transform
a. Which happens when two boundaries slide
past each other.
b. What happens when two boundaries come
together.
c. What happens when two boundaries push
apart.
Divergent boundaries
- Where tectonic plates are pulling apart
- Always oceanic plate and oceanic plate
- Magna rises toward surface and pushes plates
apart
- Makes new crust
- Causes seafloor spreading
- produces the mid-oceanic ridge
Watch this!
http://geology.com/nsta/divergent-boundarycontinental.gif
IN YOUR OWN WORDS, DESCRIBE WHAT IS HAPPENING HERE.
Transform boundary
where plates push past each other.
Can be continental or oceanic plates.
Ex: San Andreas fault in California
In your own words, what is happening
here?
Watch this!
http://geology.com/nsta/transform-boundary.gif
1 = divergent, 2 = transform
a.
b.
c.
d.
e.
Magma comes close to the surface
Happens only with oceanic plates
Happens when tectonic plates push apart
Happen with any kind of tectonic plate
Happens when tectonic plates slide past each
other
f. Results in sea-floor spreading and mid-ocean
ridges
Convergent boundary
Where boundaries push together.
Can be continental and continental
Can be oceanic and continental
Can be oceanic and oceanic
Continental and continental
convergent boundary
Results in plates being pushed up and creates
mountains
Watch this!
http://geology.com/nsta/convergentboundary.gif
Oceanic vs. continental
Results in the most dense (oceanic) layer being
subducted. This creates a subduction zone, an
area where one layer is pushed under the
other and is remelted and recycled. May result
in volcanoes
Watch this!
http://geology.com/nsta/convergent-boundaryoceanic-continental.gif
Oceanic and oceanic convergent plates
- results in a subduction zone
- May result in volcanoes and volcanic islands.
Watch this!
• http://geology.com/nsta/convergentboundary-oceanic-oceanic.gif
1= divergent, 2= convergent, 3 =
transform
a. Results in seafloor spreading
b. Results in mountains
c. Happens when tectonic plates slide past each
other
d. Happens when tectonic plates push together
e. Happens when tectonic plates pull apart
f. Creates the mid-oceanic ridge
Identify the boundary
A
B
C