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 apartConvergent – pushes togetherTransform – 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-boundary-continental.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. Magma comes close to the surfaceb. Happens only with oceanic platesc. Happens when tectonic plates push apartd. Happen with any kind of tectonic platee. Happens when tectonic plates slide past each
otherf. Results in sea-floor spreading and mid-ocean
ridges
Convergent boundary
Where boundaries push together.
Can be continental and continentalCan be oceanic and continentalCan be oceanic and oceanic
Continental and continental convergent boundary
Results in plates being pushed up and creates mountains
Watch this!
http://geology.com/nsta/convergent-boundary.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-boundary-oceanic-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/convergent-boundary-oceanic-oceanic.gif
1= divergent, 2= convergent, 3 = transform
a. Results in seafloor spreadingb. Results in mountainsc. Happens when tectonic plates slide past each
otherd. Happens when tectonic plates push togethere. Happens when tectonic plates pull apartf. Creates the mid-oceanic ridge
Identify the boundaryA B
C
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