Plate Tectonics Plate Tectonics
Dec 31, 2015
What is Plate TectonicsWhat is Plate Tectonics
• The Earth’s crust and upper mantle are broken into sections called plates
• These plates move around on top of the asthenosphere like rafts
LithosphereLithosphere
• The crust and part of the upper mantle = lithosphere
–Less dense than the material below it so it “floats”
AsthenosphereAsthenosphere
• The “plastic” layer below the lithosphere
• The plates of the lithosphere float on the asthenosphere
2 Types of Plates2 Types of Plates
• Ocean plates - plates below the oceans
• Continental plates - plates below the continents
Divergent BoundariesDivergent Boundaries
• Boundary between two plates that are moving apart or rifting
Convergent BoundariesConvergent Boundaries
• Boundaries between two plates that are colliding
• There are 3 types…
Type 1Type 1• Ocean plate colliding with a
less dense continental plate• Subduction : occurs where the
more dense plate slides under the less dense plate
Type 2Type 2
• Ocean plate colliding with another ocean plate
• The more dense plate slides under the less dense plate creating a subduction zone called a TRENCH
Type 3Type 3
• A continental plate colliding with another continental plate–a place where folded and thrust
faulted mountains form.
Transform Fault BoundariesTransform Fault Boundaries
• Boundary between two plates that are sliding past each other
• EARTHQUAKES along faults
Questions...Questions...
• What are the three types of boundaries?
• What direction do plates go for each?
• Which boundary has a subduction zone…what occurs at a subduction zone?
Convection CurrentsConvection Currents
• Hot magma in the Earth moves toward the surface, cools, then sinks again.
• Creates convection currents beneath the plates that cause the plates to move.
New sea-floor is produced at what New sea-floor is produced at what type of boundary?type of boundary?
A. convergent
B. divergent
C. transfo
rm
D. I
don’t kn
o...
0 000
A. convergent
B. divergent
C. transform
D. I don’t know
Mt. Everest was produced by this Mt. Everest was produced by this type of plate boundary.type of plate boundary.
A. convergent
B. divergent
C. transfo
rm
D. I
Don’t Kno...
0 000
A. convergent
B. divergent
C. transform
D. I Don’t Know